Handbook of Pollution Prevention and Cleaner Production Vol. 2: Best Practices in the Wood and Paper Industries

William Andrew is an imprint of Elsevier The Boulevard, Langford Lane, Kidlington, Oxford, OX5 1GB, UK 30 Corporate Drive, Suite 400, Burlington, MA 01803, USA First edition 2010 Copyright Ó 2010, Nicholas P. Cheremisinoff and Paul E. Rosenfeld. Published by Elsevier Inc. All rights reserved The rights of Nicholas P. Cheremisinoff and Paul E. Rosenfeld to be identified as the authors of this work has been asserted in accordance with the Copyright, Designs and Patents Act 1988 No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangement with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein). Notices Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary. Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility. To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein. British Library Cataloguing in Publication Data Cheremisinoff, Nicholas P. Best practices in the wood and paper industries. 1. Forest products industrydEnvironmental aspects. 2. Paper industrydEnvironmental aspects. 3. Wood-pulp industrydEnvironmental aspects. 4. Best management practices (Pollution prevention) I. Title II. Rosenfeld, Paul E. 674.8’4-dc22 Library of Congress Control Number: 2009938289 ISBN: 978-0-08-096446-1 For information on all William Andrew publications visit our website at elsevierdirect.com Printed and bound in the United States of America 09 10 11 12 11 10 9 8 7 6 5 4 3 2 1

Acknowledgements

While there are a large number of individuals who have helped to shape and contribute to this volume, we thank them all but wish to acknowledge two individuals in particular. First, we wish to acknowledge Mr Christopher Cagney Waller, B.S. in civil engineering from UCLA class of 2009, who is currently doing an internship at SWAPE under the guidance of Dr Paul Rosenfeld. Mr Waller was instrumental in editing the manuscript, in conducting research for information used in certain sections, and in preparing draft notes for the authors. The second individual we wish to acknowledge is Mr Dennis Davis of Somerville, Texas. Mr Davis worked at a wood-treating facility for more than 30 years. He provided his time and insight into the handling and operational practices of wood-treating plants. His intimate knowledge of specific practices helped to clarify a number of issues concerning the evolution of fugitive emissions at these types of facilities. Mr Davis was also a great inspiration on a personal level. He has been diagnosed with an incurable cancer associated with his many years of working in the industry sector. Throughout his illness he has shown great resolve, fortitude, and an unwavering sense for living every day to the fullest. The authors wish to thank Elsevier for their continued interest in working with us and for their efforts in the fine production of this volume.

About the authors

Nicholas P. Cheremisinoff is a chemical engineer specializing in the safe handling and management of chemicals and hazardous materials with more than 35 years of industry and applied research experience. He earned his B.Sc., M.Sc., and Ph.D. degrees in chemical engineering from Clarkson College of Technology. He is a consultant to industry and foreign governments, private sector corporations, international lending institutions such as the World Bank Organization, the US Export–Import Bank, donor agencies including the US Agency for International Development and the US Trade and Development Agency, the European Union, the US Department of Energy and the US Department of Defense, and has served as a technical consultant and advisor on industrial waste, worker safety, environmental management, and process safety. Additionally, he has served as consultant and advisor to various foreign ministries on policymaking issues concerning environmental management and responsible industry practices, including the governments of Jordan, Ukraine, the Russian Federation, and Nigeria. He is the author, co-author, or editor of 160 technical reference books. Paul E. Rosenfeld is an environmental chemist with over 20 years of experience. His focus is fate and transport of environmental contaminants, risk assessment, and ecological restoration. His project experience ranges from monitoring and modeling of pollution sources as they relate to human and ecological health. Dr Rosenfeld has investigated and designed cleanup programs and risk assessments for contaminated sites containing pesticides, radioactive waste, PCBs, PAHs, dioxins, furans, volatile organics, semi-volatile organics, chlorinated solvents, perchlorate, heavy metals, asbestos, odorants, petroleum, PFOA, unusual polymers, and fuel oxygenates. He received a B.A. in Environmental Studies from UC Santa Barbara, an M.S. in Environmental Science, Policy and Management from UC Berkeley, and a Ph.D. from the University of Washington.

Preface

This is the second volume in a series on cleaner production and pollution prevention. The intent of the series is to provide guidance on best management practices, technologies, and approaches to managing environmental aspects. The world is currently in the midst of the worst financial recession in more than 70 years. While the Chairman of the Federal Reserve announced in August of 2009 that signs of recovery show that the world financial meltdown is ending, the fact remains that unemployment is at an all-time high, with official figures in the league of 10% to unofficial estimates soaring to 20% in the USA. The media has touted the recovery as a jobless recovery – which simply means that unemployment is likely to remain high for some time, and productivity low. Looking back to the era of the last Great Depression, it took a world war and subsequent reconstruction to return industrial levels of production to normality. But in both the war years and postwar years of growth, prosperity and technological innovations, industrial activities ran with little oversight. Industrial activities consumed natural resources at paces we now acknowledge as both unsustainable and environmentally damaging. While strict environmental regulations introduced throughout the decades stretching from the early 1970s through to the mid-1990s curtailed the environmental footprint created by industry, both the new and likely next generation are still faced with an aftermath of damages to groundwater, soil, the air we breathe, and global climate change that need to be addressed. And if we misplace priorities and decide that the only way to return to prosperity is by placing environmental protection at a low priority, as was clearly national policy under the last administration in the USA, then we will simply continue down a path of destruction that has global consequences. It is both unrealistic and irresponsible to separate environmental management from infrastructure investments and business strategies and policies. Companies that make it a policy and overall strategy to only meet their minimum statutory requirements are in fact not managing both the financial and environmental aspects of their businesses responsibly. This narrow-minded approach to environmental stewardship simply is a license to pollute, because if a particular standard or regulation has not been enacted, then industry can do as it pleases with the wastes generated from manufacturing. As an example, the American Wood Preservers’ Association and the Association of American Railroads have argued for decades that there are no definitive studies that link carcinogenicity with the hundreds of chemicals that make up coal tar creosote, and with

xii

Preface

pentachlorophenol, and arsenical chemicals used in the preservation of wood. To argue differently would severely restrict the use of and even result in delisting of these chemicals since they are all registered pesticides. Despite industry, academic, medical, and governmental studies including and predating those of the National Institute of Occupational Safety and Health (NIOSH), the American Conference of Governmental Industrial Hygienists (ACGIH), the International Agency for Research on Cancer (IARC) and the Occupational Safety and Health Administration (OSHA), the wood-preserving industry continued to take a stand that as long as these chemicals are used within industry guidelines, the risks to communities, the consumer, and the environment are minimal. In short, industry knows best and will ensure that workers and neighboring communities will not be affected by exposures to such chemicals. Prior to 1992 wood-treating companies could allow these chemicals to drip and spill on to bare ground. There are wood-treating facilities in the USA that have been operating for 100 years and have eight or more decades of cumulative spills to property. In 1992 the US Environmental Protection Agency (EPA) finally got around to saying enough is enough. This practice contaminates the groundwater and creates airborne emissions that may enter into communities. So the EPA passed a standard requiring drip pads to be installed to collect the spills and drips that the industry had allowed for nearly a century. The industry understood that the chemicals it uses are toxic, linked to cancers, and can contaminate groundwater and storm water. It is no leap in logic that when contaminated groundwater and storm water travel off the plant property it carries these same chemicals for people to come into contact with from well water or when walking through puddles or swimming in lakes or fishing in streams. But because there were no statutory standards, the industry could ignore these pathways to toxic exposures. Prior to the 1990s, with the introduction of boiler industrial furnace (BIF) standards, many wood-treating facilities could burn toxic sludge and treat wood in wood-waste boilers legally. A number of facilities grandfathered 30-year-old boilers with minimal to no air pollution controls prior to these standards, burning their wastes in an uncontrolled manner, and introducing millions of pounds of polycyclic aromatic hydrocarbons (PAHs) and dioxins into the atmosphere, exposing neighboring communities. The science, technologies, and tools were there 40 years ago for stack testing, monitoring, and controlling stack emissions – but these cost money, and if there are no regulations or required standards, why should a company reduce its profits by installing and operating such equipment? This kind of sounds like a child – if you tell your 8-year-old to do what he or she thinks is best, even with warnings against consequences, what do you think they will do? On the whole, the wood-preserving industry has historically operated its facilities like toxic waste dumps. It buried, spilled, burned, stockpiled, and lagooned hundreds of millions of tons of toxic waste on properties that bordered residential communities. Since 1980, the EPA has classified 56 wood-preserving sites as Superfund sites. At about 40 of these sites, the EPA has completed the

Preface

xiii

process of selecting a cleanup strategy for the soil, sludge, sediments, and water contaminated by wood treatment wastes. If we conservatively assume that remediation costs are $20 million per site, then the cost to American taxpayers can exceed $1.1 billion. Add to this the costs for medical monitoring for communities that have been exposed to air pollution or whose groundwater has been contaminated, or continue to receive toxic emissions from contaminated soils that become airborne, or are subjected to the pollution from wood-waste boilers, as well as healthcare costs from workers and community members who are battling illnesses from chemical exposures, then the costs to society are staggering. New Jersey and New York are states that have banned the manufacture and use of creosote-treated wood. We believe this is a prelude to the demise of the industry and has long been overdue. The industry on the whole has misrepresented the dangerous nature of the chemicals it uses, has failed to act responsibly in reporting its emissions accurately, has not been transparent in quantifying its emission sources, and has misrepresented that the benefits these products bring to society outweigh the negative impacts. Many will argue that modern wood-treating plants are not environmentally damaging because there are better technologies, industry understands more, and there are stringent regulations and environmental enforcement today. But we think old habits are hard to break. While the gross housekeeping and uncontrolled waste burying and burning has been eliminated, wood-treating facilities simply do not report accurate and transparent air emissions. The same problem exists within the pulp and paper industry. The standard approach in the USA to reporting air pollution emissions is by means of calculation and not measurement. To the company, the US EPA’s AP-42 is relied upon for the application of emission factors to calculate yearly emissions and report these under the Toxics Release Inventory program, which is a legal requirement. The objective of TRI is to inform the public of pollution in their communities and to provide a basis to monitor industry activity. But emission factors are based on measurements reported by industry itself more than 30 years ago. AP-42 emission factors are not plant specific, they are not necessarily representative of all plants, they are not based on statistical sampling for a large number of facilities, they do not reflect the age and inefficiencies of older operating equipment, and they do not consider upsets and transient operating conditions that occur on a regular basis at operating plants. In examining AP-42 emission factors for the wood-treating industry, we find that emission factors for a mere eight PAHs out of a possible 130 chemicals found in this product are reported, and further all of the factors provided by industry are referenced to ambient conditions and not actual handling conditions. The same publication offers no reasonable guidelines to account for the effect of surface area with exposures from treated wood, which has a direct impact on the magnitude and duration of fugitive emissions from the surfaces of treated wood. The pulp and paper industry has similar if not identical shortcomings in its reporting of emissions. It bases emissions reporting on self-reported emissions using emission factors that were measured in the 1960s and 1970s. Stack testing

xiv

Preface

and independent emissions monitoring are performed under steady-state conditions, with upsets rarely reported or required to be reported. Such practices are unreasonable, especially based on the human health risk tools and precision of monitoring instrumentation we have available today. Furthermore, we believe that many companies simply have ignored the financial benefits associated with good environmental performance. Good environmental performance is not simply about meeting statutory requirements. It’s about staying ahead of the game. At the end of the day, business is in business to make business. The basis for our capitalist society is to make profits. When companies are short-sighted and only meet the minimum requirements of statutes, they expose the corporation, shareholders, and employees to financial liabilities from cleanup damages, future enforcement actions, and communities that seek retribution from the negative impacts of the manufacturing operations. The intent of this volume, as with others, is to focus on best management practices and technologies that may help to continually improve environmental performance. A commitment to continual environmental performance is increasingly becoming the standard of care for smart industry leaders. The term ‘‘best practices’’ does not necessarily mean the most costly. A decade ago, best practices simply meant good housekeeping. Practices such as source reduction, chemical substitution, leak detection and repair programs, measurement and monitoring, adaptation of environmental management information systems, and a whole gambit of other low-cost tools and practices can assist facilities to better manage their environmental aspects. This volume contains seven chapters. The first five chapters focus on the wood-preserving industry; however, Chapter 5 has information and discussions that are relevant to both the wood-treating and pulp and paper industry sectors. Chapter 1 provides an overview of the properties and applications of chemicals used in wood treating. Chapter 2 provides a working overview of wood-treating technology with focus on tie and utility pole treatment. Chapter 3 discusses pollution sources and methods of controlling air emissions. Chapter 4 focuses on calculation methods for air emissions from wood-treating plants. Discussions of wood-waste combustion are included in this chapter. Chapter 5 deals with pollution prevention practices in the wood-treating sector, along with discussions on conducting an initial environmental review, the application of environmental management information systems, and the structure and benefits of an environmental management system. Chapter 6 addresses the technologies, sources of pollution, and chemicals of concern and pollution control technologies within the pulp and paper sector. Chapter 7 covers pollution prevention and best practices for the sector. In this last chapter a spotlight on black liquor gasification as an emerging technology is given. Nicholas P. Cheremisinoff Ph.D. Paul E. Rosenfeld Ph.D.

1 Wood-preserving chemicals 1.1 Introduction This chapter describes the chemicals that are used in the preservation of wood. The chapter is followed by a discussion of pressure-treated wood manufacturing technologies. An understanding of both the toxic nature of chemicals used and manufacturing steps is critical to identifying and responsibly managing the many forms of pollution and waste generated in the production of treated wood products. As described in later chapters, a wood-treating plant generates both fugitive and point sources of pollution. While many of these are better managed today, historically the industry has been among the worst polluters, leaving toxic legacies that are likely to be a concern for present and future generations. The industry overall has lagged in adopting good housekeeping and source reduction practices that have been available for more than 70 years. Much of this can be attributed to an industry structure that is historically based on small fragmented business units and enterprises. The USA almost stands as an island unto itself with the industry’s continued dependence on creosote coal tars, pentachlorophenol, and arsenicals. While these chemicals unquestionably provide superior product performance as pesticides designed to kill, they bring with them negative impacts to workers, neighboring communities, and the environment. For more than 30 years the National Institute of Occupational Safety and Health (NIOSH, 1977a) and the Occupational Safety and Health Administration (OSHA, 1978) have labeled creosote as a dangerous chemical that is linked to cancer. The US Environmental Protection Agency (EPA, 1984) has defined creosote, pentachlorophenol, and arsenical treating formulations as chemicals that are potential carcinogens. Austria, India, Indonesia, New Zealand, Sweden, Switzerland, the EU/EEA member states, and Belize are among the international community that have banned, or placed severe restrictions on, the use of pentachlorophenol because of its link to carcinogenicity and the fact that the product contains dioxins. Both New York and New Jersey have banned all use of creosote in treated wood manufacturing as of 2008. There is overwhelming consensus from the scientific community and governmental organizations that the chemicals used by the US wood-preserving industry are dangerous and cancer causing. Companies that continue to use such chemicals have an obligation to employ the best available technologies and practices that eliminate these materials from entering into the air and into surface water run-off that may enter into receiving bodies or pass through communities, and from contaminating groundwater.

Handbook of Pollution Prevention and Cleaner Production Vol. 2 Copyright Ó 2010 by Elsevier Inc. All rights reserved.

2

Handbook of Pollution Prevention and Cleaner Production

1.2 Wood types and products The feedstock material used by the industry sector is wood, of which there are several varieties. Primary types of wood exploited by the industry are Douglas fir, southern pine, oak, and mixed hardwood. The products made to service the rail industry are crossties, switches (switch ties), pilings, poles, crossarms, lumber and timber, and fence posts. A crosstie is also referred to as a railroad tie or a tie. The British call a railroad tie a sleeper. It is one of the cross-braces that support the rails on a railway track. Figure 1.1 shows a stack of crossties as they are typically bundled for shipment to a customer. Rail tracks are used on railways which, together with switches, guide trains without the need for steering. The tracks consist of two parallel steel rails, which are laid upon sleepers (crossties) that are embedded in ballast to form the railroad track. The rail is fastened to the ties with spikes, lag screws, bolts, or clips such as Pandrol clips. Figure 1.2 shows crossties arranged in a track. On average, about 3000 railroad ties are used per mile of track. A rail profile is a hot rolled steel profile of a specific shape or cross-section (an asymmetrical I-beam) designed for use as the primary component of railway track. Railway rails are subject to very high stresses and have to be constructed of very-high-quality steel. Minor flaws in the steel that pose no problems in reinforcing rods for buildings can, however, lead to broken rails and dangerous derailments when used on railway tracks. The rails represent a substantial fraction of the cost of a railway line. Only a small number of rail sizes are made by the steelworks at one time, so a railway must select the nearest suitable size. Worn, heavy rail from a mainline is often reclaimed and downgraded for reuse on a branchline, siding or yard.

Figure 1.1 Stack of creosote-treated railroad ties.

Wood-preserving chemicals

3

Figure 1.2 Railroad ties comprising a section of track.

Track ballast forms the trackbed upon which railroad ties are laid. It is packed between, below, and around the ties. It is used to facilitate drainage of water, to distribute the load from the railroad ties, and also to keep down vegetation that might interfere with the track structure. This also serves to hold the track in place as the trains roll by. It is typically made of crushed stone, although ballast has sometimes consisted of other, less suitable materials. The term ‘‘ballast’’ comes from a nautical term for the stones used to stabilize a ship. Good-quality track ballast is made of crushed natural rock with particles between 28 and 50 mm in diameter; a high proportion of particles finer than this will reduce its drainage properties, and a high proportion of larger particles result in the load on the ties being distributed improperly. Angular stones are preferable to naturally rounded ones, as these interlock with each other, inhibiting track movement. Soft materials such as limestone are not particularly suitable, as they tend to degrade under load when wet, causing deterioration of the line; granite, although expensive, is one of the best materials in this regard (Ellis, 2006). Usually, a baseplate (i.e. a tie plate) is used between the rail and wood sleepers, to spread the load of the rail over a larger area of the sleeper. Sometimes spikes are driven through a hole in the baseplate to hold the rail, while at other times the baseplates are spiked or screwed to the sleeper and the rails clipped to the baseplate. Tie plates add to the stability of track, lengthen the life of wood ties, and provide uniform wear on the rail head. Tie plates are available in single- or double-shoulder design (see Figure 1.3). Steel rails can carry heavier loads than any other material. Railroad ties spread the load from the rails over the ground and also serve to hold the rails a fixed distance apart (the gauge). Ties are laid across the ballast at intervals of about two feet (roughly 3000 ties per mile). The rails are then laid atop the ties, perpendicular to them. If the ties

4

Handbook of Pollution Prevention and Cleaner Production

Figure 1.3 Examples of tie plates.

are wood, tie plates are then set atop the ties on the rail flange, and then spikes or bolts are driven through the tie plates into the ties to clamp down the rails. Historically, US railroads have used driven rail spikes to hold the rail to the tie, while European railways favor square-headed bolts that are screwed into the wood. For concrete ties, steel clips (e.g. the Pandrol clip) are used to fasten the rails. After this is done, additional ballast is then added to fill the spaces between and around the ties to anchor them in place. The ties serve as anchors and spacers for the rails, while providing a slight amount of give to accommodate weather and settling. The ties are ‘‘floating’’ in the top of the ballast. Failure of a single tie is generally insignificant to the usability and safety of the rails. Rails lie somewhat freely in tie plates and sliding movement of the rail through the plate is possible, leading to creeping rails or misaligned or unevenly spaced ties. To prevent this, anchors are placed transversely under the rail at each side of the tie to prevent slippage of the rail and the tie relative to each other. The tie anchor is usually a spring-loaded clip placed with a hammer blow (driven) or with a special lever (wrench). Wood is a versatile and effective material for use as a crosstie. However, the key properties of wood will vary with class of wood type. In order to allow for the potential use of a broad range of wood types, the wood tie properties need to be considered in terms of the categories of wood. The material properties noted herein are based on a collection of data reported from various sources on the Web and are consistent with those presented in the Manual for Railway Engineering of the American Railway Engineering and Maintenance of Way Association (AREMA, 2007). Table 1.1 provides wood property values using the following parameters: 1. Dimensions are for a standard main line wood crosstie and are based on the AREMA specification that allows a ¼-inch reduction in width and depth. The unit of measure is inches. 2. Volume is defined as the total amount of space occupied by the crosstie and is calculated based on the dimensions shown. The unit of measure is cubic feet. 3. Density is mass per unit volume and is based on reported values derived from the testing of small clear specimens of wood using ASTM procedure D-143 and US Forest Service data. Actual whole tie values may differ. The unit of measure is pounds per cubic foot.

1. Dimensions Length (in) Width (in) Depth (in)

Nominal 102 9 7

2. Volume (ft3)

Oak

Northern mixed hardwoods

Southern mixed hardwoods

Southern yellow pine

Softwood

Douglas fir

102 8.75 6.75

102 8.75 6.75

102 8.75 6.75

102 8.75 6.75

102 8.75 6.75

102 8.75 6.75

3.49

3. Density (pcf) (lb/ft3)

69.4

3.49 65.3

3.49 58.9

3.49 62.1

3.49 53.4

3.49 59.7

4. Weight (lb)

238

227

205

216

196

208

5. Moment of inertia (in4)

224

224

224

224

224

224

66.4

66.4

66.4

66.4

66.4

66.4

6. Section modulus (in3) 7. Modulus of elasticity (MOE)

106

1.22

1.29

0.95

8. Modulus of rupture (MOR) (psi)

72F

9392

8893

6810

670

418

Janka Ball

883

690

558

591

9. Rail seat compression test (psi) 10. Material surface hardness test (lb) 11. Static bending strength (in-kips) 12. Stiffness; load/deflection (in) 13. Single tie lateral push test (lb)

0.165 1950

0.157 1900

1.07

1.60

10,508

7144

9299

523

632

430

594

587

565

371

556

453

698

475

618

0.212 1800

1.49

0.134 1850

0.187 1700

Wood-preserving chemicals

Table 1.1 Typical material and tie strength properties

0.125 1800

5

6

Handbook of Pollution Prevention and Cleaner Production

4. Weight is the density multiplied by the volume. The unit of measure is pounds. 5. Moment of inertia (MOI) is a measure of the rectangular shape of the crosstie and is calculated around its neutral axis calculated based on the defined dimensions and a rectangular cross-section. The unit of measure is inches4. 6. Section modulus is a measure of the shape of the crosstie and is calculated by dividing the MOI by the greatest distance of the section from the neutral axis, calculated from dimensions and rectangular cross-section. The unit of measure is inches3. 7. Modulus of elasticity (MOE) is the rate of change of unit stress with respect to unit strain under uniaxial loading within the proportional (or elastic) limits of the material. This parameter is a measure of the stiffness of the crosstie, i.e. the relationship between load (stress) and deflection (strain). Values are average reported ones derived from testing of small clear specimens of wood using ASTM procedure D-143 and US Forest Service data. Actual whole tie values may differ. Unit of measure is pounds per square inch. 8. Modulus of rupture (MOR) is a measure of the maximum load-carrying capacity or strength of the crosstie and is defined as the stress at which the material breaks or ruptures (based on the assumption that the material is elastic until rupture occurs). Reported values are those derived from testing of small clear specimens of wood using ASTM procedure D-143 and US Forest Service data. Actual whole tie values may differ. The unit of measure is pounds per square inch. 9. The rail seat compression test is a measure of the crushing strength or load-carrying capacity of the crosstie at the rail seat (under the tie plate) and is defined as load per unit area at which compression of the wood occurs. The unit of measure is pounds per square inch. 10. The material surface hardness (Janka Ball) test is a measure of the surface hardness of the crosstie and is defined as load necessary to push a two-inch-diameter steel ball 0.25 inches into the tie surface. The unit of measure is pounds. 11. Static bending strength is a measure of the strength of the crosstie and is based on a load/deflection test carried out to failure of the wood material (test similar to C-stiffness load/deflection test). The unit of measure is inch-kips. 12. C-stiffness load/deflection is a measure of the flexibility of the crosstie and is based on a load deflection test in which a load of 10,000 lb is applied to the center of the crosstie, which is supported from below at two points 60 inches apart. The deflection is measured. The unit of measure is inches. 13. The single-tie lateral push test is a measure of the lateral resistance of a single crosstie in ballasted track and is representative of the relative resistance of the track to lateral movement in the ballast. Values are based on field tests taken by the US Department of Transportation and are based on ‘‘minimum’’ value for consolidated track adjusted to account for differences in density (weight) of the different crosstie wood materials. The unit of measure is pounds.

1.3 Chemicals used in preservation 1.3.1

Coal-tar creosote

Coal-tar creosote is a brownish black/yellowish dark green oily liquid with a characteristic sharp odor, obtained by the fractional distillation of crude coal tars. The approximate distillation range is 200–400 C as reported in

Wood-preserving chemicals

7

Table 1.2 General properties of creosote Property

Value

Synonyms

Coal-tar creosote, creosote oil, coal-tar oil, creosote P1

CAS nos.

8001-58-9; 90640-80-5 (anthracene oil); 61789-28-4

Molecular mass

Variable (complex mixture of hydrocarbons)

Boiling range

~200–400 C

Density

1.00–1.17 g/cm3 at 25 C

Viscosity

4–14 mm2/s at 40 C

Flash point

Above 66 C

Ignition temperature

500 C

Octanol/water partition coefficient (log Kow)

1.0

Solubility in organic solvents

Miscible with many organic solvents

Solubility in water

Slightly soluble/immiscible

the general public literature. Table 1.2 summarizes the general properties of creosote. The chemical composition of creosotes is influenced by the origin of the coal and also by the nature of the distilling process. This means that creosote components are rarely consistent in their type and concentration. According to the US EPA there are six major classes of compounds in creosote (Willeitner and Dieter, 1984; US EPA, 1987): 

 



 

aromatic hydrocarbons, including polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs (nonheterocyclic PAHs can constitute up to 90% of creosote by weight), and benzene, toluene, ethylbenzene and xylene compounds (known collectively as BTEX); tar acids/phenolics, including phenols, cresols, xylenols, and naphthols (tar acids, 1–3 weight %; phenolics, 2–17 weight %); tar bases/nitrogen-containing heterocycles, including pyridines, quinolines, benzoquinolines, acridines, indolines, and carbazoles (tar bases, 1–3 weight %; nitrogencontaining heterocycles, 4.4–8.2 weight %); aromatic amines, such as aniline, aminonaphthalenes, diphenylamines, aminofluorenes, and aminophenanthrenes, cyano-PAHs, benzacridine, and its methylsubstituted congeners; sulfur-containing heterocycles, including benzothiophenes and their derivatives (1–3 weight %); oxygen-containing heterocycles, including dibenzofurans (5–7.5 weight %).

Table 1.3 provides chemical analyses of several coal-tar creosotes as reported by the US EPA, including the source data that were assembled in the reporting.

8

Table 1.3 Chemical analyses of coal-tar creosotesa Chemical analysis (weight %)b

Aromatic hydrocarbons Indene Biphenyl

Tar acids/phenolics Phenol o-Cresol m-, p-Cresol 2,4-Dimethylphenol Naphthols

(B)

(C)

(D)

(E)

(F)

(G)

0.8*/1.6

2.1

1–4

0.8c

0.6 1.3

0.43 1.45

0.87 4.1

1.3/3.0* 0.9*/1.7 1.2*/2.8 2.0*/2.3

11

13–18 12–17 12.0

7.6 0.9c 2.1c

9.0*/14.7 7.3/10.0* 2.3/3.0* 21* 3.0* 2.0* 4.0* 7.6/10.0* 7.0/8.5* 1.0/2.0*

3.1 3.1

9.0 7–9

8.3c 5.2c

12.32 3.29 7.51 3.42 0.15 12.51 5.03

11.4 8.87 11.5 5.16 0.1 5.86 6.33

12.2

12–16

16.9c 8.2d

10.21 0.45 0.9

6.7 0.54 0.8

1–3.3

2–7

12.9 2.2 4.5 1.6 0.2 5.8 4.6 3.1 11.2 3.1 1.7

2–3 1–5

7.5c 5.3c

4.6 3.7 2.2 0.5 0.22 0.5–1.0 0.2 0.2 0.1

4.41 2.0

2.27 1.13

0.2–2.2 0.1–1.5

0.26

0.17

0.21 <0.1

<0.05 <0.05

0.24 0.10 0.24 0.12 0.12

0.56

0.24 0.2 0.6 0.48

2.6/3.0*

3.0 5.6

5.9 3.4 2.2 3.4

2.2

1 0.43c

(H)

0.4–1.2

0.16–0.3

2.31 0.59

0.02–0.16

Handbook of Pollution Prevention and Cleaner Production

PAHs Naphthalene 1-Methylnaphthalene 2-Methylnaphthalene Dimethylnaphthalenes Acenaphthylene Acenaphthene Fluorene Methylfluorenes Phenanthrene Methylphenanthrenes Anthracene Methylanthracenes Fluoranthene Pyrene Benzofluorenes Benz[a]anthracene Benzo[k]fluoranthene Chrysene Benzo[a]pyrene Benzo[e]pyrene Perylene

(A)

1

2.4

2d 2.0d 0.7d 4d 0.3d 3.9d 2d 2.8d 3.1d 2d

0.59 0.18 0.29

0.58 0.30 0.05

0.89 0.59 0.5

0.7

0.53

0.22

0.2

1.5

0.12

0.05d

0.21

0.3c

0.4 1.0

0.3 0.78

0.5 0.73

3.9c

3.7 23.1

<0.1 6.14

<0.1 5.59

Aromatic amines Aniline Sulfur-containing heterocycles Benzothiophene Dibenzothiophene Oxygen-containing heterocycles/furans Benzofuran Dibenzofuran Other unspecified components

5.0*/7.5

1.1

4–6

0.1

Wood-preserving chemicals

Tar bases/nitrogen-containing heterocycles Indole Quinoline Isoquinoline Benzoquinoline Methylbenzoquinoline Carbazole Methylcarbazoles Benzocarbazoles Dibenzocarbazoles Acridine

a

Adapted from Heikkila¨ (2001). Key: (A) From Lorenz and Gjovik (1972); with asterisk (*) from a literature survey; without asterisk, our own measurements of main components in an AWPA standard creosote. (B) From Nestler (1974); six creosotes, four unspecified, and two fulfilled the US federal specifications I and III. (C) From Andersson et al. (1983); Rudling and Rosen (1983); creosote used in the impregnation of railway ties. (D) From Wright et al. (1985). (E) From ITC (1990); AWPA standard creosote P1 (AWPA P1). (F) From Nylund et al. (1992); sample of German creosote; about 85 compounds were identified. (G) From Nylund et al. (1992); sample of former Soviet creosote; about 85 compounds were identified. (H) From Schirmberg (1980); three different creosote samples, all fulfilling the British standard BS 144/73/2. c Concentration in PAH fraction. d Concentration in nitrogen compound fraction. b

9

10

Handbook of Pollution Prevention and Cleaner Production

Creosotes used in wood preservation are classified according to national/ international standards in terms of specifications – e.g. American Wood Preservers’ Association (AWPA) standards P1 and P2 and the Western European Institute for Wood Preservation creosote grades A, B, and C. Prior to 1994, creosote could contain up to 20% phenolic compounds; in 1994, however, this was limited to 3% (EC, 1994). In recent years, legislation in many countries has required that the benzo[a]pyrene content of creosote be reduced. The EU (European Committee for Standardization, 2000) finalized a standard on classification and methods of testing for creosotes. European industry uses only creosote grades B and C with a benzo[a]pyrene content lower than 50 mg/kg (0.005 weight %) and, for grade C, lower volatile compounds (European Committee for Standardization, 2000). In contrast, the USA has been protective of this industry and has allowed lax requirements for coal-tar creosote. Coal-tar creosote (CAS 8001-58-9) is the most common form of creosote used in the workplace. It is referred to by the EPA as simply ‘‘creosote’’. It is a thick, oily liquid that is typically amber to black in color, and is a distillation product of coal tar. It has a burning, caustic taste. Coal-tar creosote is the most widely used wood preservative in the USA. It is used as a wood preservative and waterproofing agent for log homes, railroad ties, telephone poles, marine pilings, and fence posts. It is also a restricted-use pesticide, and is used as an animal and bird repellant, insecticide, animal dip, fungicide, and a pharmaceutical agent for the treatment of psoriasis. Because of its lethal properties, both Canada and the European Union have restricted its use and are moving towards a total ban of the product. There are approximately 300 chemicals that constitute the major compositional mix in coal-tar creosote; however, there can be up to 10,000 different chemicals in all within a typical mixture. Common synonyms are creosote (coal tar); AWPA #1; brick oil; coal creosote; coal-tar creosote; coal-tar oil (DOT); creosote (wood); creosote oil; creosote P1; creosotum; cresylic creosote; dead oil; heavy oil; liquid pitch oil; naphthalene oil; preserv-o-sote; RCRA Waste number U051; sakresote 100; tar oil; UN 1136 (DOT); and wash oil. Coal tar (CAS 8007-45-2) and coal-tar pitch (CAS 67996-93-2) are the byproducts of the high-temperature treatment of coal to make coke or natural gas. These chemical products are usually thick, black or dark brown liquids or semisolids with a naphthalene-like odor. Coal tar has a sharp, burning taste. Because of its dangerous properties both Canada and the European Union have banned the product. Coal-tar creosotes, coal tar, and coal-tar pitch are similar in composition, with the major chemicals in them that can cause harmful health effects being PAHs, phenol, and cresols. Approximately 75–85% or more of the coal tar mixture is comprised of PAHs. Coal-tar pitch is a residue produced during the distillation of coal tar and is distinct from coal tars and coal-tar creosotes. The pitch is a shiny, dark brown to black residue containing PAHs and methyl and polymethyl derivatives along

Wood-preserving chemicals

11

with heteronuclear components. Properties of PAHs are reported on the OSHA website (http://www.osha.gov/dts/sltc/methods/organic/org058/org058.html). The International Agency for Research on Cancer (IARC, 1987) defines coaltar creosote as ‘‘the fractions or blends of fractions specifically used for timber preservation’’. The US EPA simply refers to this mixture as ‘‘creosote’’. Bedient et al. (1984) have reported that mixture composition varies across production lots and manufacturers, but that an average composition contains about 85% PAHs and 2–17% phenolic compounds. The National Institute for Occupational Safety and Health (NIOSH, 1977b) defines coal-tar pitch as the tar distillation residue produced from coking. This means that the grade of pitch can vary significantly since distillation conditions such as residence time and temperature have first-order effects on the composition of the pitch. The product is comprised mainly of condensed ring aromatics, which includes two- to six-ring systems, along with minor components of phenolics and aromatic nitrogen bases. Weyand et al. (1991) and Guillen et al. (1992) have shown that the number of chemical components in coal-tar pitch is of the order of many thousands. Since commercial creosote mixtures come from different sources, which rely on different distillation parameters as well as sources of coal, one may expect that the creosote components are inconsistent in type and concentration. Weyand et al. reported two- to 20-fold differences in concentrations of several PAHs from a study of four coal tars. The IARC has determined that coal-tar creosote is a probable human carcinogen. The US EPA has determined that coal-tar creosote is a probable human carcinogen, and that coal-tar pitch is a confirmed human carcinogen. The EPA classified coal-tar creosote as a carcinogen in the 1992 Toxics Release Inventory (TRI). Skin cancer and cancer of the scrotum have resulted from longterm exposure to low levels of these chemicals, especially through direct contact with skin during wood treatment or manufacture of coal-tar-creosote-treated products, or in coke or natural gas factories. Cancer of the scrotum in chimney sweeps has been associated with prolonged skin exposure to soot and coal-tar creosote. Eating food or drinking water contaminated with a high level of creosotes causes a burning in the mouth and throat, as well as stomach pains. Brief exposure to large amounts of coal-tar creosote can result in a rash or severe irritation of the skin, chemical burns of the surfaces of the eye, convulsions, mental confusion, kidney or liver problems, unconsciousness, or even death. Longer exposure to lower levels of coal-tar creosote, coal tar, or coal-tar pitch by direct contact with skin or by exposure to the vapors from these mixtures can also result in sun sensitivity causing damage to skin in the forms of reddening, blistering, or peeling. Longer exposures to the vapors of the creosotes, coal tar, or coal-tar pitch can also cause irritation of the respiratory tract. The NIOSH recommended exposure limits (RELs) are time-weighted average (TWA) concentrations for up to a 10-hour working day during a 40-hour working week. A short-term exposure limit (STEL) is designated by ‘‘ST’’

12

Handbook of Pollution Prevention and Cleaner Production

preceding the value; unless noted otherwise, the STEL is a 15-minute TWA exposure that should not be exceeded at any time during a working day. A ceiling REL is designated by ‘‘C’’ preceding the value. Any substance that the NIOSH considers to be a potential occupational carcinogen is designated by the notation ‘‘Ca’’. The OSHA permissible exposure limits (PELs) are reported in Tables Z-1, Z-2, and Z-3 of the OSHA General Industry Air Contaminants Standard (29 CFR 1910.1000). Unless noted otherwise, PELs are TWA concentrations that must not be exceeded during any 8-hour work shift of a 40-hour working week. An STEL is designated by ‘‘ST’’ (short term) preceding the value and is measured over a 15-minute period unless noted otherwise. OSHA ceiling concentrations (designated by ‘‘C’’ preceding the value) must not be exceeded during any part of the working day; if instantaneous monitoring is not feasible, the ceiling must be assessed as a 15-minute TWA exposure. In addition, there are a number of substances from Table Z-2 (beryllium, ethylene dibromide, etc.) that have PEL ceiling values that must not be exceeded except for specified excursions. For example, a ‘‘5-minute maximum peak in any 2 hours’’ means that a 5-minute exposure above the ceiling value, but never above the maximum peak, is allowed in any 2 hours during an 8-hour working day. Because creosote and coal-tar products have such a broad composition of dangerous chemicals, a safe exposure level to the generic chemical itself is meaningless. From an inhalation exposure standpoint, the concern is for harmful PAHs. Benzo[a]pyrene is an example of one of these PAHs. It is one of the most studied of these hydrocarbons, and it is a ‘‘fingerprint’’ chemical for detecting the presence of PAHs. The benzo[a]pyrene content of coal tar is between 0.1% and 1% and it contributes to the serious potential health effects for employees exposed to emissions. Four other examples of PAH chemicals are anthracene, phenanthrene, pyrene, and carbazole, all of which are major components in creosote. PAHs are regulated by both the OSHA and EPA. Because these agencies regulate PAHs under slightly different definitions in relation to sources of emission, they refer to them by different names. The OSHA refers to them as coal-tar pitch volatiles (CTPVs) because, by definition, they come from both coke ovens and coal tar, which is derived from the coking process. The EPA calls them coke oven emissions (COEs), which by definition only relates to emissions from coke ovens. Both agencies, however, are referring to the same group of chemicals, including those of particular concern, the PAHs. The term CTPV (COE) is understood to mean ‘‘benzene-soluble fraction’’ and is therefore a measure of the presence of anthracene, benzo[a]pyrene, phenanthrene, acridine, chrysene, and pyrene (i.e. the benzene-soluble fraction is the sum of those components collected in a sample and determined to be soluble in benzene). CTPVs or COEs from hot industrial processes volatilize and then condense from coal or hot tar as soon as they contact normal (ambient) air temperature. CTPVs evaporate from the surface of hot coal tar during tar-processing

Wood-preserving chemicals

13

operations. COEs (including PAHs) escape at coke ovens during coal charging (filling an oven), coking, and coke pushing (removal of coke room an oven). In the case of wood-treating plants, CTPVs escape from treating cylinders when the wood product is removed after the treating cycle. The vapor pressure of CTPVs and COEs is so low at normal temperature that they are treated as particulate matter. Because they are particles, they can be removed from the air by particulate filters when process temperatures are near ambient. The standards to bear in mind are:    

OSHA General Industry PEL – 0.2 mg/m3 OSHA Construction Industry PEL – 0.2 mg/m3 TWA ACGIH threshold limit value (TLV) – 0.2 mg/m3 TWA; Appendix A1 (Confirmed Human Carcinogen) NIOSH REL – 0.1 mg/m3 TWA; Cyclohexane Extractable Fraction, Potential Carcinogen.

Standard procedures and analytical methods are provided by the OSHA (for recommended detailed analytical and sampling procedures, go to http://www. osha.gov/dts/sltc/methods/organic/org058/org058.html). In the OSHA sampling method, air samples are collected by drawing known amounts of air through cassettes containing glass fiber filters (GFFs). The filters are analyzed by extracting benzene and gravimetrically determining the benzene-soluble fraction (BSF). If the BSF exceeds the appropriate PEL, then the sample is analyzed by high-performance liquid chromatography (HPLC) with a fluorescence (mL) or ultraviolet (UV) detector to determine the presence of selected PAHs. The following are OSHA-recommended target concentrations that should not be exceeded in the workplace environment:       

0.20 0.15 8.88 0.79 9.00 3.27 2.49

1.3.2

mg/m3 for coal-tar pitch volatiles (PEL) mg/m3 for coke oven emissions (PEL) mg/m3 (1.22 ppm) for phenanthrene mg/m3 (0.11 ppm) for anthracene mg/m3 (1.09 ppm) for pyrene mg/m3 (0.35 ppm) for chrysene mg/m3 (0.24 ppm) for benzo[a]pyrene.

Pentachlorophenol

Pentachlorophenol (commonly referred to as PCP or Penta; CAS 87-86-5) is a chlorinated hydrocarbon. Its molecular structure is that of a phenol group with five chlorine atoms. Pentachlorophenol (C6HCl5O) is a synthetic fungicide that is part of the organochloride family. It has historically been used as a pesticide, herbicide, and wood preservative chemical. A major use of PCP has been as a wood preservative for power line and telephone poles, cross-arms and fence posts. PCP was first produced in the 1930s and has been marketed under various names, including Santophen, Pentachlorol, Chlorophen, Chlon, Dowicide 7, Pentacon, Penwar, Sinituho and Penta. It is available in two forms, PCP itself or

14

Handbook of Pollution Prevention and Cleaner Production

as the sodium salt of PCP, which dissolves readily in water. In the past, it has been used as a herbicide, insecticide, fungicide, algaecide, disinfectant and as an ingredient in antifouling paint, and in some agricultural seed applications (for nonfood uses), leather, masonry, wood preservation, cooling tower water, rope, and in paper mill systems. Common synonyms are: penta-ate; pentachlorophenate sodium; pentachlorophenol, sodium salt; pentachlorophenoxy sodium; pentaphenate; phenol, pentachloro-, sodium derivative monohydrate; sodium PCP; sodium pentachlorophenate; sodium pentachlorophenolate; and sodium pentachlorophenoxide. The standard AWPA P8 defines the properties of pentachlorophenol preservative. Pentachlorophenol solutions for wood preservation contain no less than 95% chlorinated phenols, as determined by titration of hydroxyl and calculated as pentachlorophenol. The performance of pentachlorophenol and the properties of the treated wood are influenced by the properties of the solvent used. The AWPA P9 standard defines solvents and formulations for organic preservative systems. A commercial process using pentachlorophenol dissolved in liquid petroleum gas (LPG) was introduced in 1961, but later research showed that field performance of PCP/LPG systems was inferior to that of PCP systems. Thus, PCP/LPG systems are no longer used. The heavy petroleum solvent included in AWPA P9 Type A is recommended as preferable for maximum protection, particularly when wood treated with pentachlorophenol is used in contact with the ground. The heavy oils remain in the wood for a long time and do not usually provide a clean or paintable surface. Pentachlorophenol in AWPA P9, Type E solvent (dispersion in water), is only approved for above ground use in lumber, timber, bridge ties, mine ties, and plywood for southern pines, coastal Douglas fir, and redwood. In the pressure process method of preserving wood, the wood is placed in a pressure-treating vessel, where it is immersed in PCP and then subjected to applied pressure. In the nonpressure process method, PCP is applied by spraying, brushing, dipping, and soaking. Utility companies save millions of dollars in replacement poles, because the life of these poles increases from approximately 7 years for an untreated pole to about 35 years for a preservative-treated pole using this chemical. In some instances we have learned that wood-treating facilities in the past have added PCP to creosote production runs on an intermittent basis when fungicide problems have occurred. PCP is highly toxic and carcinogenic. These factors are almost intuitive when one considers the synthesis route. PCP can be produced by the chlorination of phenol in the presence of catalyst (anhydrous aluminum or ferric chloride) and a temperature of up to approximately 191 C. This process results in a product that is only 84% and 90% pure. During the process several contaminants, including other polychlorinated phenols, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans, are produced. These impurities are more toxic than the PCP itself. The World Health Organization (http://www.inchem.org/documents/ehc/ehc/ ehc71.htm#SectionNumber:2.1) notes many more impurities in technical PCP,

Wood-preserving chemicals

15

depending on the manufacturing method. Among these are chlorophenols, particularly isomeric tetrachlorophenols, and several microcontaminants, mainly polychlorodibenzodioxins (PCDDs), polychlorodibenzofurans (PCDFs), polychlorodiphenyl ethers, polychlorophenoxyphenols, chlorinated cyclohexenons and cyclohexadienons, hexachlorobenzene, and polychlorinated biphenyls (PCBs). Table 1.4 provides PCP compositional data compiled and reported by the World Health Organization. The quality of PCP depends on the source and date of manufacture. Furthermore, analytical results may be extremely variable, particularly with regard to earlier results, which should be considered with caution. Some early studies from the 1970s report chlorinated 2-hydroxydiphenyl ethers, which may be converted to dioxins during gas chromatography, thus giving a false indication of a higher level of PCDDs. Unlike these ‘‘predioxins’’, other isomers are not direct precursors of dioxins, and are labeled ‘‘isopredioxins’’ in early studies. The toxicity of PCDDs and PCDFs depends both on the number and the position of chlorine substituents. Thus a precise characterization of PCP impurities is essential. The presence of highly toxic 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-T4CDD) has been confirmed once in commercial PCP samples at concentrations up to 1100 ng/kg. The higher polychlorinated dibenzodioxins and dibenzofurans are more characteristic of PCP products. Hexachlorodibenzo-p-dioxin (H6CDD), which is considered highly toxic and carcinogenic, has been reported by the World Bank Organization (WBO) at levels of 0.03–35 mg/kg. Also octachlorodibenzop-dioxin (OCDD) is present in relatively high amounts in unpurified technical PCP. The identification of 2-bromo-3,4,5,6-tetrachlorophenol as a major contaminant in some commercial PCP samples (ca. 0.1%) has been reported. The thermal decomposition of PCP or Na-PCP results in significant amounts of PCDDs and PCDFs, depending on the thermolytic conditions. Pyrolysis of alkali metal salts of PCP at temperatures above 300 C results in the condensation of two molecules to produce OCDD. PCP itself forms traces of OCDD only on prolonged heating in bulk and at temperatures above 200 C. Beginning in 1984, the US EPA recommended restricted use of PCP. The following are EPA-approved precautions:  





Logs treated with pentachlorophenol should not be used for log homes. Wood treated with pentachlorophenol should not be used where it will be in frequent or prolonged contact with bare skin (for example, chairs and other outdoor furniture), unless an effective sealer has been applied. Pentachlorophenol-treated wood should not be used in residential, industrial, or commercial interiors except for laminated beams or building components that are in ground contact and are subject to decay or insect infestation, and where two coats of an appropriate sealer are applied. Sealers may be applied at the installation site. Wood treated with pentachlorophenol should not be used in the interiors of farm buildings where there may be direct contact with domestic animals or livestock that may crib (bite) or lick the wood.

Technical RhonePoulenc (86%)

104,000 <1000 ns

ns ns ns

50,000 20 ns

70,000 ns 70,000

<0.05 ns <0.5 <0.5 <1.0

<0.05 ns 1 6.5 15

<0.2 <0.2 9 235 250

<0.001 ns 3.5 130 600

<0.01 ns 5 150 600

ns ns 30 80 80

ns ns <0.5 <0.5 <0.5

ns ns 3.4 1.8 <1.0

<0.2 <0.2 39 280 230

ns 0.2 10 60 150

ns ns ns ns ns

ns

ns

400

ns

ns

ns

Technical Dow (88.4%)

Technical Dow (98%)

Technical Dow (90.4%)

30,000 ns ns

44,000 <1000 62,000

2700 500 5000

Dibenzo-p-dioxins (mg/kg PCP) TetrachloroPentachloroHexachloroHeptachloroOctachloro-

<0.1 <0.1 8 520 1380

<0.05 ns 4 125 2500

Dibenzofurans (mg/kg PCP) TetrachloroPentachloroHexachloroHeptachloroOctachloro-

<4 40 90 400 260

Hexachlorobenzene

ns

Handbook of Pollution Prevention and Cleaner Production

Technical Dow (ns)

Technical Dyn. Nobel (87%)

Technical Monsanto (84.6%) Phenols (mg/kg PCP) TetrachloroTrichloroHigher chlorinated phenoxyphenols

16

Table 1.4 WBO-reported impurities (mg/kg PCP) in different technical PCP products

Wood-preserving chemicals



 

   



17

In interiors of farm buildings where domestic animals or livestock are unlikely to crib (bite) or lick the wood, pentachlorophenol-treated wood may be used for building components that are in ground contact and are subject to decay or insect infestation, and where two coats of an appropriate sealer are applied. Sealers may be applied at the installation site. Do not use pentachlorophenol-treated wood for farrowing or brooding facilities. Do not use treated wood under circumstances where the preservative may become a component of food or animal feed. Examples of such sites would be structures or containers for storing silage or food. Do not use treated wood for cutting boards or countertops. Only treated wood that is visibly clean and free of surface residue should be used for patios, decks, and walkways. Do not use treated wood for construction of those portions of beehives that may come into contact with the honey. Pentachlorophenol-treated wood should not be used where it may come into direct or indirect contact with public drinking water, except for uses involving incidental contact such as docks and bridges. Do not use pentachlorophenol-treated wood where it may come into direct or indirect contact with drinking water for domestic animals or livestock, except for uses involving incidental contact such as docks and bridges.

The following are OSHA safe exposure limits:    

PEL – 0.5 mg/m3 (skin) PEL TWA – 0.5 mg/m3 (skin) ACGIH TLV – 0.5 mg/m3 TWA (skin); Appendix A3 (Confirmed Animal Carcinogen with Unknown Relevance to Humans) NIOSH REL – 0.5 mg/m3 TWA (skin).

According to the United Nations Environment Programme (UNEP, 1991/1996) extensive use of PCP to treat wood, and to a lesser extent use in homes and gardens, together with its physical characteristics, indicate that there is likely to be widespread human exposure occurring partially through skin contact, but mainly through inhalation, which is the most dangerous route of exposure to PCP. The UNDP has reported that this has been confirmed by many reports of its occurrence in the general environment and its presence in body fluids, both in the general population and in exposed workers. Airborne levels of PCP production and woodpreservation facilities have ranged from several mg/m3 to more than 300 mg/m3 in some work areas. Domestic use, such as indoor application of wood preservatives and paints based on PCP or PCP-treated wood or indoor wood panels or boards, has historically led to high concentrations in the indoor atmosphere. Pentachlorophenol is not listed under the Pesticide Safety Directorate as being authorized for use in the UK. The primary UK legislation controlling pesticides is the Food and Environmental Protection Act (FEPA 1985 – as amended) and the Control of Pesticides Regulations (COPR 1986) made under this act. The UK legislation implementing the relevant EU Directive on releases to water is found in the ‘‘Surface Waters (Dangerous Substances) (Classification) Regulations, 1997 (SI 1997/2560)’’. It is also controlled under the UK Pollution Prevention

18

Handbook of Pollution Prevention and Cleaner Production

and Control Regulations. Pentachlorophenol is also regulated under EC Council Directive 76/769/EEC relating to restrictions on the marketing and use of dangerous substances and preparations, Council Directive EC 76/464/EEC on the discharge of certain dangerous substances to the aquatic environment, 96/61/ EEC on integrated pollution prevention and control, and EC Directive 76/464: ‘‘Pollution of the aquatic environment by dangerous substances’’ (plus daughter directives); it is also on the list of 11 substances under review as potential ‘‘priority hazardous substances’’ under the proposed Water Framework Directive. Directive 86/280/EEC sets limit values on the discharge of pentachlorophenol to water. It is a UK ‘‘Red List’’ pollutant, the presence of which in the environment is of particular concern. Internationally it is listed as a substance for priority action on its control under the OSPAR and Helsinki Conventions. The US EPA is reassessing PCP as part of its re-registration program for older pesticides. Federal law directs EPA to periodically re-evaluate older pesticides to ensure that they continue to meet current safety standards. Pentachlorophenol was one of the most widely used biocides in the USA before regulatory actions to cancel and restrict certain nonwood-preservative uses of pentachlorophenol in 1987. Pentachlorophenol is a standardized oil-borne preservative listed in the AWPA Book of Standards under P8, Section 1. It now has no registered residential uses. The production of pentachlorophenol for wood preservation began on an experimental basis in the 1930s. In 1947 nearly 3200 metric tons of pentachlorophenol were reported to have been used in the USA by the commercial woodpreserving industry. Before the 1987 Federal Register Notice that canceled and restricted certain nonwood uses, pentachlorophenol was registered for use as a herbicide, defoliant, mossicide, and as a disinfectant. As of 2002, approximately 11 million pounds of pentachlorophenol were produced (http://www.epa. gov/pesticides/factsheets/chemicals/pentachlorophenol_main.htm).

1.3.3

Inorganic arsenicals

Inorganic arsenicals are those wood-preserving chemicals that contain arsenic. Arsenic is a naturally occurring semi-metallic element with an atomic weight of 74.92. Pure arsenic (which is rarely found in nature) exists in three allotropic forms: yellow (alpha), black (beta), and gray (gamma). Many inorganic arsenic compounds are found in the environment, frequently occurring as the sulfide form in complex minerals containing copper, lead, iron, nickel, cobalt, and other metals. Arsenic compounds occur in trivalent and pentavalent forms; common trivalent forms are arsenic trioxide and sodium arsenite, and common pentavalent forms are arsenic pentoxide and the various arsenates. Arsenic and arsenic compounds occur in crystalline, powder, amorphous, or vitreous forms. Elemental arsenic has a specific gravity of 5.73, sublimes at 613 C, and has a very low vapor pressure of 1 mmHg at 373 C. Many of the inorganic arsenic compounds occur as white, odorless solids with specific gravities ranging from about 1.9 to more than 5. Arsenic trioxide, the most common arsenic compound in commerce, melts at 312 C and boils at 465 C (ATSDR, 2000). In water,

Wood-preserving chemicals

19

elemental arsenic is insoluble, calcium arsenate and arsenites are sparingly soluble, and arsenic trioxide, arsenic pentoxide, and other arsenicals are soluble. Arsenic pentoxide, potassium arsenite, and the sodium salts are soluble in ethanol. Arsenic, arsenic pentoxide, arsenic trioxide, the calcium arsenites, lead arsenate, and potassium arsenate are soluble in various acids. When heated to decomposition, arsenic compounds emit toxic arsenic fumes. The end-use distribution of inorganic arsenic compounds in the USA has varied over the years. Inorganic arsenic compounds were widely used as pesticides from the mid-1800s to the mid-1900s and were used in medicine until the 1970s, primarily for treatment of leukemia, psoriasis, and asthma. By the mid1970s, arsenic use shifted from pesticides to wood preservatives, and by 1980 wood preservatives were the primary use. Since about the mid-1990s, arsenic trioxide used in wood preservation has accounted for 86–90% of total USA arsenic consumption. Wood treated with chromated copper arsenate (CCA), known as ‘‘pressure-treated wood’’, has been used widely to protect utility poles, building lumber, and foundations from decay and insect attack. Wood preservatives are expected to remain the major domestic use for arsenic; however, a voluntary phase-out of CCA for certain residential uses (e.g. in wood for decks, play structures, fencing, and boardwalks) that went into effect on 31 December 2003 will reduce this use of arsenic. CCA will continue to be used in wood products for industrial use. The USA is the world’s leading consumer of arsenic; however, arsenic has not been produced in the USA since 1985, when production of 2200 metric tons (4.9 million pounds) was reported. All arsenic metal and compounds consumed in the USA now are imported. Before 1985, US arsenic production varied widely, reaching a peak of 24,800 metric tons (54.7 million pounds) in 1944. Average annual production was 12,200 metric tons (26.9 million pounds) from 1935 to 1959 and 5100 metric tons (11.2 million pounds) from 1960 to 1985. US imports of arsenic and arsenic compounds increased as production decreased, with annual averages of about 8300 metric tons (18.3 million pounds) from 1935 to 1959, 11,300 metric tons (24.9 million pounds) from 1960 to 1985, and 23,300 metric tons (51.4 million pounds) from 1986 to 2002. Annual exports reached a peak of 4200 metric tons (9.3 million pounds) in 1941, but since 1985 have ranged from 36 to 1350 metric tons (79,000 to 3 million pounds). Arsenic imports are mainly in the form of arsenic trioxide; arsenic metal generally accounts for about 3–5% of imports. Inorganic arsenic compounds are known human carcinogens. Epidemiological studies and case reports of humans exposed to arsenic compounds for medical treatment, in drinking water, or occupationally have demonstrated that exposure to inorganic arsenic compounds increases the risk of cancer. Cancer tissue sites include the skin, lung, digestive tract, liver, bladder, kidney, and lymphatic and hematopoietic systems (organs and tissues involved in the production of blood). Skin cancer has been reported in individuals exposed to arsenic for therapeutic reasons, sometimes in combination with other cancers, such as angiosarcoma (blood-vessel tumors) of the liver, intestinal and bladder

20

Handbook of Pollution Prevention and Cleaner Production

cancer, and meningioma (tumors of the membranes covering the central nervous system); however, only skin cancer has been clearly associated with medical use of arsenic in epidemiological studies (http://ntp.niehs.nih.gov/ntp/roc/eleventh/ profiles/s015arse.pdf).

1.3.4

Water-borne preservatives

Water-borne preservatives are used when cleanliness and paintability of the treated wood are required. Several formulations involving combinations of copper, chromium, and arsenic have shown high resistance to leaching and good performance in service. Water-borne preservatives are included in specifications for items such as lumber, timber, posts, building foundations, poles, and piling. Historically they have been used extensively by the railroad industry and for general construction markets. The AWPA has reported that dual treatment (water-borne copper-containing salt preservatives followed by creosote) is possibly the most effective method of protecting wood against all types of marine borers. The AWPA standards have recognized this process as well as the treatment of marine piles with high retention levels of ammoniacal copper arsanate (ACA), ammoniacal copper zinc arsenate (ACZA), or chromated copper arsenate (CCA). Water-borne preservatives leave the wood surface comparatively clean, paintable, and free from objectionable odor. CCA and acid copper chromate (ACC) must be used at low treating temperatures (38–66 C (100–150 F)) because they are unstable at higher temperatures. Because water is added to the wood in the treatment process, the wood must be dried after treatment to the required moisture content for the end use intended. As already noted, inorganic arsenicals are a restricted-use pesticide. Standard wood preservatives used in water solution include ACC, ACZA, and CCA (Types A and C). Other preservatives in AWPA P5 include alkylammonium compound (AAC) and inorganic boron. Water-borne wood preservatives, without arsenic or chromium, include ammoniacal copper quat (ACQ) (Types B and D), copper bis(dimethyldithiocarbarmate) (CDDC), ammoniacal copper citrate (CC), and copper azole Type A (CBA-A), for above ground use only. The following is a brief description of the major water-borne preservatives: 



Acid copper chromate (ACC). This contains 31.8% copper oxide and 68.2% chromium trioxide (AWPA P5). The solid, paste, liquid concentrate, or treating solution can be made of copper sulfate, potassium dichromate, or sodium dichromate. Use of ACC is generally limited to cooling towers that cannot allow arsenic leachate in cooling water. Ammoniacal copper zinc arsenate (ACZA). This is used in the USA but not in Canada. It is commonly used on the West coast for the treatment of Douglas fir. Wood heated with ACZA performs and has characteristics similar to those of wood treated with CCA. ACZA contains approximately 50% copper oxide, 25% zinc oxide, and 25% arsenic pentoxide dissolved in a solution of ammonia in water (AWPA P5). The weight of ammonia is at least 1.38 times the weight of copper oxide.

Wood-preserving chemicals







 



21

To aid in solution, ammonium bicarbonate is added (at least equal to 0.92 times the weight of copper oxide). A similar formulation, ammoniacal copper arsenate (ACA), is used in Canada. Chromated copper arsenate (CCA). Type A is only being used by a few treaters in California. CCA Type A is high in chromium. Service data on treated poles, posts, and stakes installed in the USA since 1938 have shown that CCA Type A provides excellent protection against decay fungi and termites. CCA Type B (I-33) is a formulation whose commercial use in the USA started in 1964, but it is no longer used in significant quantities. CCA Type B is high in arsenic and has been commercially used in Sweden since 1950. CCA Type C (Wolmanmently) is the most common formulation of CCA being used. Type C composition was selected by AWPA technical committees to encourage a single standard for CCA preservatives. Ammoniacal copper quat (ACQ). There are basically two types of ACQ preservatives (AWA P5): Type B (ACWB; ammoniacal) and Type D (ACWD; amine-based). ACQ is used for many of the same applications as are ACZA and CCA, but it is not recommended for use in salt water. ACFB, the ammoniacal formulation, is better able to penetrate difficult-to-treat species such as Douglas fir and it provides a more uniform surface appearance. Copper bis(dimethyldithiocarbamate) (CDDC). This is a reaction product formed in wood as a result of the dual treatment of two separate treating solutions. The first treating solution contains a maximum of 5% bivalent copper–ethanolamine (2aminoethanol), and the second treating solution contains a minimum of 2.5% sodium dimethyldithiocarbamate. Ammoniacal copper citrate (CC). This has 62.3% copper as copper oxide and 35.8% citric acid dissolved in a solution of ammonia in water (AWPA P5). Copper azole Type A (CBA-A). This has 49% copper as Cu, 49% boron as boric acid, and 2% azole as tebuconazole dissolved in a solution of ethanolamine in water (AWPA P5). Inorganic boron (borax/boric acid). Borate preservatives are readily soluble in water, are highly leachable, and should only be used above ground where the wood is protected from wetting. They are effective against decay, termites, beetles, and carpenter ants. Borates are odorless and can be sprayed, brushed, or injected. They will diffuse into wood that is wet. Borates are widely used for log homes, natural wood finishes, and hardwood pallets. Compounds are derived from the mineral sodium borate, which is the same material used in laundry additives.

1.3.5

Other wood-preserving chemicals

Copper naphthenate Copper naphthenate is an organometallic compound that is a dark-green liquid imparting this color to the wood. Weathering turns the color of the treated wood to light brown after several months of exposure. The wood may vary from light brown to chocolate brown if heat is used during treatment of the wood. The AWPA P8 standard defines the properties of copper naphthenate, and AWPA P9 covers the solvents and formulations for organic preservative systems. Copper naphthenate has been used commercially since the 1940s for many wood products. It is a reaction product of copper salts and naphthenic acids,

22

Handbook of Pollution Prevention and Cleaner Production

which are usually obtained as by-products in petroleum refining. Copper naphthenate is not a restricted-use pesticide but is handled as an industrial pesticide. It may be used for superficial treatment, such as by brushing with solutions with a copper content of 1–2%.

Chlorothalonil Chlorothalonil (CTL; tetrachloroisophthalonitrile) is an organic biocide that is used to a limited extent for mold control in CCA-treated wood (AWPA P8). It is effective against wood decay fungi and wood-destroying insects. The CTL has limited solubility in organic solvents and very low solubility in water, but it exhibits good stability and leach resistance in wood. The solvent used in the formulation of the preservative is AWPA P9 Type A.

Chlorothalonil/chlorpyrifos Chlorothalonil/chlorpyrifos (CWCPF) is a preservative system composed of two active ingredients (AWPA P8). The ratio of the two components depends upon the retention specified. Chlorothalonil is an effective fungicide, and chlorpyrifos is very effective against insect attack. The solvent used for formulation of this preservative is specified in AWPA P9.

Oxine copper (copper-8-quinolinolate) Oxine copper (copper-8-quinolinolate) is an organometallic compound. The formulation consists of at least 10% copper-8-quinolinolate, 10% nickel-2ethylhexanoate, and 80% inert ingredients (AWPA P8). It is used as a standalone preservative for above-ground use for sapstain and mold control and is also used for pressure treating. A water-soluble form can be made but the solution is corrosive to metals. Oxine copper solutions are greenish brown, odorless, toxic to both wood decay fungi and insects, and are reported to have a low toxicity to humans and animals. Because of its low toxicity to humans and animals, oxine copper is the only EPA-registered preservative permitted by the US Food and Drug Administration for treatment of wood used in direct contact with food. Some examples of its uses in wood are commercial refrigeration units, fruit and vegetable baskets and boxes, and water tanks. Oxine copper solutions have also been used on nonwood materials, such as webbing, cordage, cloth, leather, and plastics.

Zinc naphthenate Zinc naphthenate is similar to copper naphthenate but is less effective in preventing decay from wood-destroying fungi and mildew. It is light colored and does not impart the characteristic greenish color of copper naphthenate, but it does impart an odor. Water-borne and solvent-borne formulations are available.

Wood-preserving chemicals

23

Zinc naphthenate is not used for pressure treating and is not intended as a standalone preservative.

Bis(tri-n-butyltin) oxide Bis(tri-n-butyltin) oxide, commonly called TBTO, is a colorless to slightly yellow organotin compound. It is soluble in many organic solvents but insoluble in water. It is not used for pressure treating or as a stand-alone preservative for inground use. TBTO concentrate contains at least 95% bis(tri-n-butyltin) oxide by weight and 38.2–40.1% tin (AWPA P8). This preservative has lower toxicity, causes less skin irritation, and has better paintability than does pentachlorophenol, but it is not effective against decay when used in ground contact. TBTO is recommended only for above-ground use, such as millwork. It has been used as a marine antifoulant, but this use has been almost eliminated because of the environmental impact of tin on shellfish.

3-Iodo-2-propynyl butyl carbamate 3-Iodo-2-propynyl butyl carbamate (IPBC) is a preservative intended for nonstructural, above-ground use only (e.g. millwork). It is not used for pressuretreating applications such as decks. The IPBC preservative is included as the primary fungicide in several water-repellent/preservative formulations under the trade name Polyphase and marketed by retail stores. It is not an effective insecticide. Water-borne and solvent-borne formulations are available. Some formulations yield an odorless, treated product that can be painted if dried after treatment. IPBC is also being used in combination with didecyldimethylammonium chloride in a sapstain-mold formulation (NP-I). IPBC contains 97% 3-iodo2-propynyl butyl carbamate, with a minimum of 43.4% iodine (AWPA P8).

Alkylammonium compound Alkylammonium compound (AAC) or didecyldimethylammonium chloride (DDAC) is a compound that is effective against wood decay fungi and insects. It is soluble in both organic solvents and water, and is stable in wood. It is used as a component of ammoniacal copper quat (ACQ; a water-borne preservative) for above-ground and ground contact and is a component of NP-1 for sapstain and mold control.

Propiconazole Propiconazole is an organic triazole biocide that is effective against wood decay fungi but not against insects (AWPA P8). It is soluble in some organic solvents. It has low solubility in water and is stable and leach resistant in wood. It is currently used for above-ground and sapstain control application in Europe and Canada. Solvents used in the formulation of the preservative are specified in either AWPA P9 Type C or Type F.

24

Handbook of Pollution Prevention and Cleaner Production

4,5-Dichloro-2-N-octyl-4-isothiazolin-3-one This is a biocide that is effective against wood decay fungi and insects. It is soluble in organic solvents but not in water, and is stable and leach resistant in wood. This biocide is not currently being used as a wood preservative. The solvent used in the formulation of the preservative is specified in AWPA P9 Type C.

Tebuconazole Tebuconazole (TEB) is an organic triazole biocide that is effective against wood decay fungi. It is soluble in organic solvents but not in water, and it is stable and leach resistant in wood. Currently, TEB has no commercial application at present. The solvents used in the formulation of this preservative are specified in either AWPA P9 Type C or Type F.

Chlorpyrifos Chlorpyrifos (CPF) is a preservative (see AWPA P8) that is very effective against insect attack but not fungal attack. If fungal attack is a concern, then CPF should be combined with an appropriate fungicide, such as chlorothalonil/chlorpyrifos or IPBC/chlorpyrifos.

Water-repellent and nonpressure treatments Water-repellent preservatives retard the ingress of water when wood is exposed above ground. Preservatives help reduce dimensional changes in the wood as a result of moisture changes when the wood is exposed to rainwater or dampness for short periods. As with any wood preservative, the effectiveness in protecting wood against decay and insects depends upon the retention and penetration obtained. Preservatives are most often applied using nonpressure treatment like brushing, soaking, or dipping. Since the focus of this section of the volume is on pressure-treated wood, we only discuss this in passing. Preservative systems containing water-repellent components are sold under various trade names. Many are sold to the public for household and farm use. Federal specification TT-W-572 stipulates that such preservatives be dissolved in volatile solvents, such as mineral spirits, and do not cause appreciable swelling of the wood. The preservative chemicals in Federal specification TT-W-572 may be one of the following:    

not less than 5% pentachlorophenol; not less than 1% copper in the form of copper naphthenate; not less than 2% copper in the form of copper naphthenate for tropical environments; not less than 0.045% copper in the form of oxine copper for uses when foodstuffs will be in contact with the treated wood.

Wood-preserving chemicals

25

References American Railway Engineering and Maintenance of Way Association (AREMA), 2007. Manual for Railway Engineering, Chapter 30, Section 30-A-1. Andersson, K., Levin, J.O., Nilsson, C.A., 1983. Sampling and analysis of particulate and gaseous polycyclic aromatic hydrocarbons from coal tar sources in the working environment. Chemosphere 12, 197–207. ATSDR, 2000. ‘‘Toxicological Profile for Arsenic’’. NTIS Accession No. PB2000108021. Atlanta, GA: Agency for Toxic Substances and Disease Registry. pp. 466. Bedient, P.B., Rodgers, A.C., Bouvette, T.C., et al., 1984. Groundwater Quality at a Creosote Waste Site. Groundwater 22, 318–329. EC, 1994. European Parliament and Council Directive 94/60/EC of 20 December 1994, amending for the 14th time Directive 76/769/EEC on the approximation of the laws, regulations and administrative provisions of the Member States relating to restrictions on the marketing and use of certain dangerous substances and preparations. Official Journal of the European Communities. L365:1. Ellis, I., 2006. Ellis’ British Railway Engineering Encyclopedia. Available at Lulu.com. European Committee for Standardization, 2000. Derivates from coal pyrolysis d coal tar based oils: Creosotes d specifications and test methods. Brussels, European Committee for Standardization, pp. 1–11 (Project Reference 00317007 prEN 14998; CEN/TC 317/WG2). Guillen, M.D., Iglesias, M.J., Dominguez, A., et al., 1992. Polynuclear Aromatic Hydrocarbon Retention Indices on SE-54 Stationary Phase of the Volatile Components of a Coal Tar Pitch: Relationships between Chromatographic Retention and Thermal Reactivity. Journal of Chromatography. 591, 287–295. Heikkila¨, P. 2001. Respiratory and dermal exposure to creosote [Dissertation]. Kuopio, University of Kuopio (Kuopio University Publications C. Natural and Environmental Sciences 120). Available at http://www.uku.fi/vaitokset/2001/. International Agency for Research on Cancer (IARC), 1987. Monographs on the Evaluation of Carcinogenic Risk to Humans. Supplement 7, Vols 1–47. IARC, World Health Organization. ITC, 1990. Information about coal-tar creosote for wood preservation. Prepared by Tar Industries Services (TIS) for International Tar Conference, Paris, March, pp. 1–79. Lorenz, L.F., Gjovik, L.R., 1972. Analysing creosote by gas chromatography: relationship to creosote specifications. Proceedings of the Annual Meeting of the American Wood-Preservers’ Association 68, 32–42. National Institute of Occupational Safety and Health (NIOSH), 1977a. Criteria for a Recommended Standard – Occupational Exposure to Coal Tar Products. NIOSH, Washington, DC, September. National Institute of Occupational Safety and Health (NIOSH), 1977b. Criteria for Recommended Standard: Occupational Exposure to Coal Tar Products, NIOSH-78– 107. SRI International for US Department of Health and Human Services, NIOSH, Cincinnati, OH. Nestler, F.M., 1974. Characterization of wood-preserving coal-tar creosote by gas – liquid chromatography. Analytical Chemistry 46, 46–53. Nylund, L., Heikkila¨, P., Hameila, M., Pyy, L., Linnainmaa, K., Sorsa, M., 1992. Genotoxic effects and chemical compositions of four creosotes. Mutation Research 265, 223–236.

26

Handbook of Pollution Prevention and Cleaner Production

Occupational Safety and Health Administration (OSHA), 1978. Occupational Guidelines for Coal Tar Pitch Volatiles. OSHA, Washington, DC, September. Rudling, J., Rosen, G. 1983. Kemiska ha¨lsorisker vid tra¨impregnering II. Stockholm, Arbetarskyddsstyrelsen (Report No. Underso¨kningsrapport 1983:11) [cited in Heikkila¨, 2001]. Schirmberg, R., 1980. [The concentration of polycyclic aromatic compounds in some creosotes.] Analytical report to the Finnish Wood Preservers’ Association. Helsinki, Finnish Institute of Occupational Health (in Finnish) [cited in Heikkila¨, 2001]. United Nations Environment Programme (UNEP), 1991/1996. Joint FAO/UNEP Programme for the Operation of Prior Informed Consent. Food and Agriculture Organization of the United Nations, UNEP, Rome/Geneva, 1991, amended 1996. US Environmental Protection Agency (EPA), 1984. Wood Preservative Pesticides: Creosote, Pentachlorophenol and Inorganic Arsenicals, Position Document 4. EPA, Washington, DC, July. US Environmental Protection Agency (EPA), 1987. Weyand, E.H., Wu, Y., Patel, S., et al., 1991. Urinary Excretion and DNA Binding of Caol Tay B6C3FI Mice Following Ingestion. Chemical Research and Toxicology 4 (4), 466–473. Willeitner, H., Dieter, H., 1984. Steinkohlenteero¨l. Holz als Roh- und Werkstoff 42, 223–231. Wright, C.W., Later, D.W., Wilson, B.W., 1985. Comparative chemical analysis of commercial creosotes and solvent refined coaldII. Materials by high resolution gas chromatography. Journal of High Resolution Chromatography, & Chromatography Communications 8, 283–289.

2 Wood-preserving technology 2.1 Introduction Wood preservation involves the pressure or thermal impregnation of chemicals into wood. The process results in long-term resistance to attack by fungi, bacteria, insects, and marine borers. This has the economic advantage of reducing maintenance costs for industry sectors such as the railroad industry, which faces significant costs for replacement of ties. On average, approximately 3000 railroad ties are needed for every mile of track that is installed. Hence the longer ties remain in service, the lower the maintenance costs for supporting rail operations. This chapter provides a description of the technologies and equipment used. As noted in the first chapter, there are two general classes of wood preservatives: oils, such as creosote and petroleum solutions of pentachlorophenol; and waterborne salts that are applied as aqueous solutions. The effectiveness of the preservative varies and can depend not only upon its composition, but also upon the quantity injected into the wood, the depth of penetration, the conditions to which the treated material is exposed in service, and the species of wood treated. There is considerable art in the preservation of wood, for which other authoritative references may be consulted. The intent of this volume is to examine pollution and waste management, and ways to responsibly manage these, and as such only a cursory examination of the manufacturing technologies from the standpoint of product performance is made.

2.2 General facility overview Figure 2.1 provides a simplified overview of a wood-treating plant. In examining this flow chart there are 12 unit processes seen to be involved: 



Chemical delivery (1) and storage (2) – for large-scale production facilities the chemicals are delivered usually in bulk form in tanker cars by rail. Creosote and oil are offloaded into a loading rack and typically sent to above-ground storage tanks (see Figure 2.2, for example). In the case of products like chromated copper arsenate (CCA), these are often delivered in drums and then mixed with water on site in blending tanks. For pentachlorophenol, there are a variety of ways in which this product is received at a facility, such as in solid form (in which case it is blended in oil in on-site blending tanks), in solution form usually in oil contained in drums or, for large-scale shipments by rail tanker cars, as a suspension in oil. Blend and working tanks (3) – because it is expensive to use straight runs of creosote, blend formulations are used. The American Wood Preservers’ Association (AWPA) provides specific formulations for various blends of creosote in extender oils (often Number 5 or 6 oils). This reduces the cost of production and maximizes

Handbook of Pollution Prevention and Cleaner Production Vol. 2 Copyright Ó 2010 by Elsevier Inc. All rights reserved.

28

Handbook of Pollution Prevention and Cleaner Production

WASTE WATER & AIR EMISSIONS

WOOD RECEIVING AND STORAGE4 STACK AIR EMISSIONS

STORAGE TANKS2

STEAM FOR PLANT

LOAD ONTO TRAMS

NAPHTHA

SAW MILL CUTTING, SIZING, SHAVING5

OPEN AIR SEASONING

CHEMICAL DELIVERY1

BLEND AND WORKING TANKS3

~ 14 MONTHS6

VAPOR DRYING

LOAD ONTO TRAMS8

(12 HOURS)7

TREATING CYLINDERS

(18-23 HOURS)9

DRIP PAD10

12

TREATED WOOD TO STOCK YARD11

WOOD WASTE BOILER

Figure 2.1 Generalized flow scheme for a wood-treating plant.

Figure 2.2 Tankers delivering creosote coal tar and extender oil to a treating plant.

Wood-preserving technology















29

serviceability of the product. Typical blend ratios include 70/30 (i.e. 70% extender oil and 30% creosote) and 50/50 blends. Working tanks are used to recover unused treating chemicals from the treating cycle. Wood receiving and storage (4) – untreated wood is received at plants generally in large quantities and must be staged and examined to ensure it meets quality inspection criteria. Saw mill (5) – these are saw mill and debarking operations. For many plants precut timbers in rough form are purchased from suppliers and final shaping, sizing, cutting, and finishing operations are performed. Considerable wood waste is generated in these operations. Seasoning (6 and 7) – untreated wood that is received must be dried before being chemically treated. This process is referred to as seasoning. Seasoning can be performed by a variety of techniques, including natural, thermal, or by means of chemical treatment. Tram loading and treating (8 and 9) – once the wood has been shaped and seasoned it is loaded on to special cars called trams and inserted into retorts that are called treating cylinders. This is the heart of the process, where chemicals are impregnated into the wood, accomplishing the process of preservation. Drip pad (10) – since about 1992 wood-treating plants have been required by law to operate with a concrete staging area where the treated wood that is removed from the retort is allowed to sit until all excess chemicals on the surface of the wood stop dripping. Prior to this, many treatment plants simply allowed chemicals to drip on to the bare ground, resulting in contamination of soil, groundwater and surface water run-off. Treated wood stock yard (11) – a certain amount of wood is maintained in an on-site inventory in a stock yard area. Many of the larger plants in the USA are hundreds of acres in size in order to accommodate several months of back inventory. Boilers (12) – Figure 2.1 shows a wood waste boiler, but boiler operations may also be natural gas fed only. The purpose of a boiler is to generate steam, which is used predominantly to operate the treating cylinders. Wood waste boilers have been an effective means of managing the wood waste generated from on-site sawmill operations. A few facilities have been innovative in applying cogeneration technologies where both steam and electricity are generated. Some wood-treating facilities have grossly abused this technology by burning treated wood and process sludge in the past, generating harmful dioxins and polycyclic aromatic hydrocarbons (PAHs).

2.3 Timber preparation When wood is harvested (referred to as ‘‘green’’ wood), the material contains significant amounts of free water trapped in the wood cell cavities. The presence of this water slows down the permeation of the preservative chemical and also promotes wood rot. The wood moisture must first be reduced prior to chemical treatment (typically down to 15% moisture for railroad ties). The replacement of the water with the preservative is what imparts good weathering and resistance to attack. The timber that is treated must be sound and suitably prepared. The wood has to be well peeled and then seasoned or conditioned in the treating cylinder before treatment. It is also highly desirable that all machining be completed before

30

Handbook of Pollution Prevention and Cleaner Production

treatment in order to avoid post-treatment and the generation of hazardous waste. Machining may include incising to improve the preservative penetration in woods that are resistant to treatment, in addition to the operations of drilling or boring of holes. Peeling round or slabbed products is necessary to enable the wood to dry quickly enough to avoid decay and insect damage, and to allow the preservative to evenly penetrate the article. Even strips of thin inner bark may prevent satisfactory penetration from occurring. Any patches of bark left on during treatment usually fall off in time, thus exposing untreated wood and allowing decay to reach the interior of the article. There are a number of reasons why wood must be seasoned prior to treatment. First, seasoning reduces gross weight and hence subsequent shipping and handling costs are reduced. Additionally, seasoning imparts dimensional stability, increases strength, increases fastener holding power and joint strength, increases electrical resistance, improves paintability and glueability, and finally also improves the thermal properties of wood. Drying wood below the fiber saturation point also renders it impervious to biological degradation, provided the wood remains dry. Attack by wood-destroying fungi is prevented. Moisture reduction is accomplished by using air-seasoning or artificial conditioning treatments. In natural seasoning, unseasoned wood is exposed to the open air. The wood dries slowly until it comes into approximate equilibrium with the relative humidity of the air. A problem with this approach is that some wood species will rot before the air-drying process is complete. Figure 2.3 is a photograph showing how wood is typically stacked in a stockyard. Precut ties are stacked in a configuration to allow natural air currents to pass through rows and over the surfaces of ties to aid in moisture vaporization. Because certain wood species will rot before air drying can be completed, wood is also artificially conditioned by one of three primary methods: (1) steaming and vacuum; (2) boiling under vacuum (commonly referred to as the

Figure 2.3 Green ties in a stockyard undergoing air seasoning.

Wood-preserving technology

31

Boulton process); and (3) kiln drying. A fourth method is naphtha vapor drying, but this method has largely been abandoned. It does, however, have some historical importance because of the pollution problems it created. Conditioning treatments remove a substantial amount of moisture from the wood and also serve to heat the wood to a more favorable treating temperature. Steaming and Boultonizing have the added effect of disinfecting the wood. In segregated systems, conditioning is performed in separate clean cylinders that do not contain any preservative. Steaming and vacuum methods of conditioning are used primarily for treating southern pine poles. Steaming and vacuuming are generally performed in a dedicated cylinder but past, and likely current practice, at some facilities is to perform the step in the same cylinder used for treating the wood. In this process, the wood charge is heated with live steam. Then, a vacuum is drawn. The Boulton process is used primarily for Douglas fir and hardwoods. It is usually performed in the same cylinder used to treat the wood. In this process, the cylinder is charged with green wood, and then heated preservative is used to heat the wood charge for 1–24 hours. At that point, a vacuum is drawn. The preservative is returned to the work tank. This step is referred to as ‘‘blowback’’ from the practice of using compressed air to blow the preservative back into the work tank. While most treatment systems rely on pumps to withdraw preservative from the treatment cylinder and return it to the work tank, and in fact do not actually blow back the preservative, the term is still used to refer to this step of the process. Wood-drying kiln technologies include conventional, dehumidification, solar, vacuum, and radio frequency. Conventional wood-drying kilns are of either packagetype (side loader) or track-type (tram) construction. Many hardwood lumber kilns are side-loader kilns in which fork trucks are used to load lumber packages into the kiln. Softwood lumber kilns are typically track types in which lumber packages are loaded on kiln/track cars for loading the kiln. Modern high-temperature, high-airvelocity conventional kilns can typically dry 1-inch-thick green lumber in 10 hours down to a moisture content of 18%. In contrast, 1-inch-thick green ‘‘red oak’’ requires about 28 days to dry down to a moisture content of 8%. The heat is typically introduced into a kiln by running steam through a series of fin/tube heat exchangers controlled by on/off pneumatic valves. Less common are proportional pneumatic valves or electrical actuators. Humidity is removed via a system of vents. In general, cool dry air is introduced at one end of the kiln while warm moist air is expelled at the other. Hardwood conventional kilns also require the introduction of humidity via either steam spray or cold water misting systems to prevent the relative humidity inside the kiln from dropping too low during the drying cycle. Fan directions are typically reversed periodically to ensure even drying of larger kiln charges. Softwood lumber kilns generally operate at temperatures below 240 F. Hardwood lumber kiln drying schedules typically keep the dry bulb temperature below 180 F. Difficult-to-dry species do not exceed 140 F. Dehumidification kilns are similar to conventional kilns with comparable drying times. Heat is primarily supplied by an integral dehumidification unit,

32

Handbook of Pollution Prevention and Cleaner Production

which also serves to remove humidity. Auxiliary heat is often provided early in the schedule, where the heat required may exceed the heat generated by the direct heating unit. Solar kilns are conventional kilns, typically built to keep initial investment costs low. Heat is provided via solar radiation, while internal air circulation is typically passive. Newer wood-drying technologies include the use of reduced atmospheric pressure to attempt to speed up the drying process. A variety of vacuum technologies exist, varying primarily in the method by which heat is introduced into the wood charge. Hot water platen vacuum kilns use aluminum heating plates with the water circulating within as the heat source, and typically operate at significantly reduced absolute pressure. Discontinuous and SSV (superheated steam vacuum) use atmosphere to introduce heat into the kiln charge. Discontinuous technology allows the entire kiln charge to come up to full atmospheric pressure, the air in the chamber is then heated, and finally vacuum is pulled. SSV kilns run at partial atmospheres (typically around one-third of full atmospheric pressure) in a hybrid of vacuum and conventional kiln technology (SSV kilns are significantly more popular in Europe, where the locally harvested wood is easier to dry versus species found in North America). Radiofrequency þ vacuum (RF/ V) kilns use microwave radiation to heat the kiln charge, and typically have the highest operating cost due to the heat of vaporization being provided by electricity rather than local fossil fuel or waste wood sources. The air emissions produced by wood kilns, including their heat source, can be significant. Typically, the higher the operating temperature of the kiln, the more emissions are generated (per pound of water removed). This is especially true in the drying of thin veneers and in the high-temperature drying of softwoods. Figure 2.4 is a photograph of a conventional kiln used in the conditioning of poles. Vapor drying is a form of chemical conditioning that has been performed in the past using a solution of naphtha. A tie plant in Somerville, Texas, for example, used naphtha for the seasoning of railroad ties. The advantage of this technique is that it can reduce the time required over air seasoning. Air seasoning can take 12–14 months whereas chemical treatment can accomplish moisture removal within 7 hours. In this practice the green wood is charged to the treating cylinder (retort), the cylinder is then filled with naphtha and the temperature is raised. The naphtha extracts the water, creating a solution of sap water in the petroleum hydrocarbon. The cylinder is then drained and a vacuum is pulled. Then the creosote oil mixture is introduced to begin treatment. This is analogous to the Boulton process, but instead of using the treating chemical creosote, a petroleum solvent is employed for the purpose of seasoning. The recovered naphtha/sap water solution is run to a still and the naphtha is recovered in an overhead condenser. The sap water becomes a waste stream. Because the separation is not perfect, the waste stream contains significant amounts of naphtha. A problem with naphtha is that among other constituents, it contains benzene, which is a carcinogen, and hence it must be carefully managed. Naphtha

Wood-preserving technology

33

Figure 2.4 A kiln in operation seasoning poles.

treatment also has a major disadvantage in that an inferior product is made. The Somerville Tie Plant railroad ties were discovered in the late 1980s to have nearly one-third of the service life over a properly treated railroad tie. Properly treated railroad ties may last 30 or more years in service depending on conditions in the field. The reduced service life is attributed to the deleterious effect of xylene found in naphtha, which negatively impacts the lubricating properties of creosote. Xylene levels were reported in a company study as being an important quality control parameter that needs to be kept at low levels in order to maximize creosote impregnation of the wood.

2.4 Wood treating To appreciate the technologies used to treat wood, we must recognize some of the characteristics of wood. While we generally consider wood to be a solid material, it must be borne in mind that it is plant material containing plant cells. The basic wood cell is often referred to as a fiber or a longitudinal tracheid. A simple physical model is to pinch a soda straw at both ends. This in essence is what wood fiber looks like, i.e. it is long, slender, and hollow. The thickness of the cell wall varies, as does the size of the cell cavity. Early wood or spring wood cells usually have thin walls and large cavities. Late wood or summer wood cells usually have thick walls and small cavities. Each growing season produces both early wood and late wood. Each new annual growth ring is formed just beneath the bark of the tree. The cell walls of wood fibers consist of small bits of cellulose imbedded in a matrix of hemicellulose. A thin layer of lignin cements all of these wood fibers together, much like the mortar in a brick wall. All of these constituents are sugars formed from carbon, hydrogen, and oxygen. The cavities of adjacent cells are interconnected by tiny passageways called pits. While these pits often act as simple holes through adjacent cell walls, their structure

34

Handbook of Pollution Prevention and Cleaner Production

is more complicated and they are sometimes obstructed. Water in the living tree moves from cell to cell by means of these pits. The movement of water in drying lumber or utility poles is often helped along by these pits. Similarly, the impregnation of wood with chemical solutions or oils is aided by the presence of these pits. Another consideration before discussing the technologies is wood species. Hardwoods have vessels but softwoods do not. The open ends of vessels are called pores. Hardwoods are sometimes called porous woods because of these vessels. Several specialized longitudinal cells are joined together end to end in each vessel. The diameter and distribution of the vessels vary among wood species. Oak, elm, and ash have large vessels in the early wood portion of each annual ring. Poplar, maple, and gum have smaller vessels distributed evenly throughout the wood. Tree species with needles and cones such as pines, spruces, true firs, and Douglas fir are called softwoods. Broad-leaf tree species such as oaks, maples, gum, and yellow poplar are called hardwoods. The wood of the softwood species is made up mostly of longitudinal fibers with a small percentage of rays. The hardwood species usually have larger rays and contain a significant volume of vessels. Douglas fir and southern pine are the principal softwood species used for preservative treatment. This includes construction lumber and round timbers. Oak and gum are the most commonly used hardwoods, with most of these in the form of rail ties. The reader undoubtedly knows that each new growth ring is formed between the bark and the wood of the previous season. This new wood is superimposed upon the wood of the previous season. This new wood will live as conductive tissue for about 15 years. It is referred to as sapwood because its function is to conduct water from the root system to the crown of the plant. Annual rings that have served their time and are covered by 15 or so newer layers of wood die. There then follows a period of transformation from sapwood to heartwood. The new heartwood becomes a disposal area for waste products of respiration occurring in other parts of the tree. Rays are a means of transporting these waste products into the heartwood. The nature of these chemicals varies from one tree species to another. Color, odor, and toxicity to decay fungi are the variables. The principal significance of sapwood and heartwood to the wood-preserving industry is that heartwood is difficult to treat. The dry sapwood of southern pine is relatively easy to impregnate with preservative solutions. The heartwood segment of these same timbers or lumber is difficult to impregnate. This pattern follows with other species also, except that the ease of treating the sapwood diminishes. Preservative effectiveness is influenced by a number of variables, including the protective value of the preservative chemical, the method of application, the extent of penetration, and the retention of the preservative in the treated wood. Even with an effective preservative, good protection cannot be expected with poor penetration or substandard retention levels. The species of wood, proportion of heartwood and sapwood, heartwood penetrability, and moisture content are some of the variables that influence the results of treatment. For various wood products, the preservatives and retention levels listed in Federal Specification TT-W-57I and the AWPA Commodity Standards should be consulted. Table 2.1 provides a listing of some of the standards relied upon by the industry.

Application

Creosote

Creosote solutions

Creosote– petroleum

Pentachlorophenol, P9, Type A

AWPA standard

Ties (crossties and switch ties)

6–8

7–8

7–8

0.35–0.4

C2/C6

Poles (lengths > 16 ft) – utility

7.5–16

7.5–16

7.5–16

0.30–0.85

C4

Poles (lengths > 16 ft) – building: round and sawn

9–13.5

NR

NR

0.45–0.68

C4/C23/C24

Posts (lengths < 16 ft) – agricultural, round and sawn, fence

8–10

8–10

0.40–0.50

NR

C2/C5/C16

Posts (lengths < 16 ft) – commercial: residential construction, round and sawn, fence

8–12

8–12

8–12

0.50–0.60

C2/C5/C15/C23

Posts (lengths < 16 ft) – highway construction: fence, guide, sign and sight

8–10

8–10

8–10

0.40–0.50

C2/C5/C14

Posts (lengths < 16 ft) – highway construction: guardrail and spacer blocks

10–12

10–12

10–12

0.50–0.60

C2/C5/C14

Piles – salt water, borer hazard moderate

20

20

NR

NR

C3/C14/C18

Piles – salt water, borer hazard severe

NR

NR

NR

NR

Piles – dual treatment

20

20

NR

NR

C3/C14/C24

Bridge and mine ties – salt water

25

25

NR

NR

C2/C9

Bridge and mine ties – soil and fresh water

10

10

10

0.5

C2/C9

Bridge and mine ties – above ground

8

8

8

0.4

C2/C9

Wood-preserving technology

Table 2.1 Standards and retentions (in lb of treating chemicals per ft3 wood treated) according to AWPA standards

35

36

Handbook of Pollution Prevention and Cleaner Production

Wood-treating (wood-preserving) technologies are classified as pressure processes and nonpressure processes. Those technologies that are based on pressure impregnate the wood with preservative under force. In contrast, nonpressure processes involve technologies that are based on thermal practice in which heat is applied, or by means of nonthermal processes, such as brushing, spraying, dipping, and soaking. Nonpressure processes generally rely on oilborne preservatives. In pressure processes treatment is accomplished in steel cylinders or retorts, which we have referred to as treating cylinders. A standard size used by the industry is 2–3 m (6–9 ft) in diameter and up to 46 m (150 ft) or more in length. These vessels are built to withstand working pressures up to 1720 kPa (250 pounds per square inch, psi). The wood is loaded on special carts called tram cars and moved into the retort (treating cylinder), which is then closed and filled with preservative. Figures 2.5–2.7 show railroad ties being loaded and unloaded from a treating cylinder. Applied pressure forces preservatives into the wood until the desired amount has been absorbed. Three processes, the full cell, modified full cell, and empty cell, are used. The processes are distinguished by the sequence in which vacuum and pressure are applied to the retort. The terms ‘‘empty’’ and ‘‘full’’ refer to the level of preservative retained in the wood cells. The full-cell process achieves a high level of retention of preservative in the wood cells, but less penetration than the empty-cell process. The empty-cell process achieves relatively deep penetration with less preservative retention than does the full-cell process.

Figure 2.5 A small locomotive (referred to as a switch engine) used to push wood into treating cylinders.

Wood-preserving technology

37

Figure 2.6 Ties being removed from a treating cylinder.

The various types of treating processes are summarized in Table 2.2. A review of this table will provide the reader with a general understanding of the general technologies. Figure 2.8 shows a photograph of a treating cylinder. Treatment pressures vary from about 345 to 1723 kPa (50 to 250 psi), depending on the wood species and the ease with which the wood takes the treatment. The most common pressure range is from about 862 to 1207 kPa (125 to 175 psi).

Figure 2.7 Closeup photo of the front end of a loaded tram. Typically 55–60 ties can be loaded on to a single tram. Tram trains may be 17 car lengths or more.

General description

Operational steps

Full cell (Bethel)

Used when maximum preservative retention levels are desired, such as when treating timbers with creosote for protection against marine borers. In addition to creosote, the full-cell process is also used with water-borne preservatives.

1. The charge of wood is sealed in the treating cylinder, and an initial vacuum is applied for approximately half an hour to remove as much air as possible from the wood and from the cylinder. 2. The preservative, either heated or at ambient temperature depending on the system, enters the cylinder without breaking the vacuum. 3. After the cylinder is filled, it is pressurized until no more preservative will enter the wood or until the desired preservative retention is obtained. 4. At the end of the pressure period, the pressure is released, and the preservative is removed from the cylinder. 5. A final vacuum may be applied to remove the excess preservative that would otherwise drip from the wood. If the wood is steam-conditioned, the preservative is introduced after the vacuum period following steaming. In segregated systems, the steam conditioning and preservative application steps are conducted in separate cylinders. The final steps in the process are the unloading of the retort and storage of the treated wood.

Modified full cell

Generally used for the application of water-borne preservatives. Method is similar to the full-cell process except for the initial vacuum levels.

The modified full-cell process uses less vacuum than the full cell; the vacuum levels are determined by the wood species being treated and the preservative retention levels desired. Steps essentially same as full-cell methods.

Empty cell

Achieves deep preservative penetration with a relatively low net preservative retention level. If oil preservatives are used, the empty-cell process most likely will be used, provided it will yield the desired retention level. Compressed air is used to drive out a portion of the preservative absorbed during the pressure period.

The Rueping process and the Lowry process are the two most commonly used emptycell processes. Both use compressed air to drive out a portion of the preservative absorbed during the pressure period (see descriptions below).

Handbook of Pollution Prevention and Cleaner Production

Process

38

Table 2.2 Summary of major wood-treating processes

Variation of the empty-cell process.

Compressed air is forced into the treating cylinder containing the charge of wood to fill the wood cells with air prior to preservative injection. Pressurization times vary with wood species. For some species only a few minutes of pressurization are required, while more resistant species may require pressure periods of 30 minutes to 1 hour. Air pressures used typically range from 172 to 690 kPa (25 to 100 psi) depending on the net preservative retention desired and the resistance of the wood. After the initial pressurization period, preservative is pumped into the cylinder. As the preservative enters the treating cylinder, the air escapes into an equalizing or Rueping tank at a rate that maintains the pressure within the cylinder. When the treating cylinder is filled with preservative, the pressure is raised above that of the initial air and maintained until the wood will take no more preservative or until enough has been absorbed to leave the desired preservative retention level after the final vacuum. After the pressure period, the preservative is removed from the cylinder and surplus preservative is removed from the wood with a final vacuum. This final vacuum may recover 20–60% of the gross amount of preservative injected. The treating cylinder is then unloaded and the treated wood stored.

Lowry process

Empty-cell process without the initial air pressure.

Preservative is pumped into the treating cylinder without either an initial air pressurization or vacuum, trapping the air that is already in the wood. After the cylinder is filled with the preservative, pressure is applied and the remainder of the process is identical to the Rueping process. The advantage of the Lowry process is that full-cell equipment can be used without the accessories required by the Rueping process, such as an air compressor, an extra tank for the preservative, or a pump to force the preservative into the cylinder against the air pressure. However, both processes are widely used.

Wood-preserving technology

Rueping process

39

40

Handbook of Pollution Prevention and Cleaner Production

Figure 2.8 A typical treating cylinder.

Many woods are sensitive to high treating pressures, especially when hot. The AWPA standards permit a maximum pressure of 1034 kPa (150 psi) in the treatment of Douglas fir, 862 kPa (125 psi) for redwood, and 1723 kPa (250 psi) for oak. Even lower pressures are reportedly used on such woods in commercial practice. The AWPA CI standard requires that the temperature of creosote and creosote solutions, as well as that of the oil-borne preservatives, during the pressure period should not exceed 93 C (200 F) for western red cedar and 99 C (210 F) for all other wood species. With a number of water-borne preservatives, especially those containing chromium salts, maximum temperatures are limited to avoid premature precipitation of the preservative. The AWPA specifications require that the temperature of the preservative during the entire pressure period should not exceed the maximum of 49 C (120 F) for acid copper chromate and CCA, and 60 C (150 F) for ammoniacal copper arsenate, ammoniacal copper citrate, ammoniacal copper quat (ACQ) Type 8, ACQ Type D, ammoniacal copper zinc arsenate, copper azole Type A, and copper bis(dimethyldithiocarbamate). The limit for inorganic boron is 93 C (200 F). The terms penetration and retention refer to a property of the treated article that is important to the quality of the preservative treatment. Penetration levels vary widely, even in pressure-treated material. In most species, heartwood is more difficult to penetrate than sapwood. As a general rule, species differ greatly in the degree to which their heartwood may be penetrated. For this reason, incising is used. Incising tends to improve penetration of preservative in many refractory species, but those highly resistant to penetration will not have deep or uniform penetration, even when incised. Penetration in unincised heart faces of these species may occasionally be as deep as 6 mm (1/4 in) but is often not more than 1.6 mm. The deeper penetration is highly desirable to avoid exposing untreated wood when checks occur.

Wood-preserving technology

41

Complete penetration of the sapwood is considered to be the ideal in all pressure treatments. It can often be accomplished in small-size timbers of various commercial woods, and with skillful treatment it may often be obtained in piles, ties, and structural timbers. Practically, however, the operator cannot always ensure complete penetration of sapwood in every piece when treating large pieces of round material with thick sapwood – for example, poles and piles. Therefore, specifications permit some tolerance. Preservative retentions are expressed in terms of pounds per cubic foot of wood. CCA salt treatments range from 0.25 pounds per cubic foot for aboveground applications and 0.40 pounds per cubic foot for ground contact applications to 0.60 pounds per cubic foot for permanent wood foundations. Creosote and penta-petroleum retentions range from 8 to 16 pounds per cubic foot.

3 Pollution and pollution controls 3.1 Introduction Wood-treating plants generate fugitive and point sources of air emissions plus both solid and liquid wastes. A point source is an emission that is fixed and/or uniquely identifiable, such as a stack or vent. Fugitive emissions are those emissions entering into the atmosphere that are not released through a stack, vent, duct, pipes, storage tank, or other confined air stream. These emissions include area emissions and equipment leaks. Examples of point sources of air emissions are vents from storage tanks, stack emissions from boilers, and treating cylinder vents. Examples of fugitive sources of air emissions are vapors resulting from leaking piping components, pumps and compressors, off-gassing from the surfaces of warm freshly treated wood, treating cylinder vapors that are not captured during final stages of vacuum, chemical vapors from surface ponds, fugitive dust emissions from machinery and vehicular traffic on plant roads and in stockyards, diesel and other combustion system exhausts, kiln emissions, fugitive dusts resulting from on-site remediation and construction projects, and vapors from channels and ditches that may be contaminated with treating chemicals and oils. Among the liquid wastes are sap water generated in the treatment process, boiler blowdown, and contaminated storm water run-off to outfalls. Solid wastes can consist of sawdust, shavings and bark from timber preparation operations, damaged treated wood and off-spec treated product, sludge from treating cylinders, treated kiln sticks, and contaminated adsorbents generated from the cleanup of incidental spills. This chapter discusses the major waste and emission streams. The fate and transport of major pollution streams are considered in this chapter along with various control technologies and practices. Pollution prevention practices are discussed in the latter part of this chapter.

3.2 Sources of waste and pollution 3.2.1

Solid wastes

The primary sources of solid wastes in a wood-treating plant are from timber preparation processes, sludge generated in the retorts (treating cylinders), sludge generated from wastewater treatment, off-spec and damaged treated wood, sweepings and adsorbents from incidental spills and drippings of treating chemicals, and miscellaneous sources such as kiln sticks. Handbook of Pollution Prevention and Cleaner Production Vol. 2 Copyright Ó 2010 by Elsevier Inc. All rights reserved.

44

Handbook of Pollution Prevention and Cleaner Production

The largest waste stream is by far the waste generated from timber preparation. In a very general sense, large amounts of woody residues and wood waste are generated annually in the USA. In 2002, an estimated 240 million metric tons were generated during the extraction of timber from US forest lands, from forestry cultural operations, in the conversion of forest land to nonforest uses, in the initial processing of round wood timber into usable products, in the construction and demolition of buildings and structures, and in the manufacture, use, and disposal of solid wood products (http://www.treesearch.fs.fed.us/pubs/ 9135). The major sources of waste wood are timber harvesting and processing residues, which include woody forest residues and primary timber-processing mill residues, and urban wood waste, which includes construction and demolition (C&D) waste and municipal solid waste (MSW). Each type of waste wood differs in recyclability. Timber harvesting and processing generated nearly 178 million metric tons of woody residues in 2002, with 86 million metric tons being unused and deemed available for recovery. In comparison, urban waste wood in the MSW and C&D waste streams totaled 63 million metric tons of waste wood, with 27 million metric tons remaining unused and deemed available for recovery. These estimates are based on published waste generation rates and recoverability, measures of economic activity, and trends in virgin wood use in specific markets. In wood-treating plants wood wastes comprising bark, sawdust, shavings, and pieces of cut timber represent a valuable source of clean biomass fuel (see Figure 3.1 as an example). This waste stream may be burned in wood-waste boilers, for example, to generate steam and electricity, or processed in gasifiers to generate thermal and electrical energy, or to make diesel fuel via syngas conversion technologies. The other forms of waste are toxic. These wastes cannot simply be burned in a wood-waste boiler because they contain treating chemicals and potentially can

Figure 3.1 Sawdust generated in the timber preparation stage of a pole-treating plant.

Pollution and pollution controls

45

result in the formation of dioxins as products of incomplete combustion. These wastes also can no longer be buried or spread on to property as was typically practiced a mere 20 years ago. Some wood-treating plants, for example, collected the sludge from treating cylinders and spread it about their property to fill in potholes on plant roads and as a covering to suppress fugitive dust. Other irresponsible actions included feeding toxic sludge into wood-waste boilers, thus generating dangerous polycyclic aromatic hydrocarbons (PAHs), dioxins, and furans, which poisoned communities. One facility studied (the Somerville Tie Plant) had a practice of applying sand to the track area in front of its treating cylinders in order to improve the traction of its switch engine (a switch engine is a small company-owned locomotive that pushes trams into treating cylinders and removes them when the treating cycle is complete). The undercarriages and wheels of the trams dragged the sand into treating cylinders, where it became contaminated with treating chemicals. When the trams were removed, a sludge containing 50% sand along with water and treating chemicals was dragged out on a daily basis. To dispose of this waste the Somerville Tie Plant spread the sludge about its property and burned large amounts of this waste in its woodwaste boiler. This created dioxins and PAH contaminants found in later years in attic dust sampling of people’s homes and in a local school. Another older practice discovered at tie-treating plants is the use of kiln sticks. In order to improve the penetration of treating chemicals into wood, the practice of inserting wooden slats between layers of poles and rail ties to be treated was performed. Wood that is stacked on to trams is tightly packed, and as such not all surfaces receive the benefit of exposure to treating chemicals during the treatment process. The kiln sticks create a gap between layers of wood, thus allowing creosote coal tar and pentachlorophenol oil mixes to coat the surfaces of the wood being treated in the retort. While this practice improves product quality, it also creates a toxic waste stream. At the Somerville Tie Plant, for example, a reported 1 ton per day of this waste stream was generated. Prior to the enforcement of the Resource Conservation and Recovery Act (RCRA) in the industry sector, vast amounts of these wastes were burned in wood-waste boilers and in conical tepee burners, and buried in unlined landfills within the properties of wood-treating plants. A simple pollution prevention practice that eliminates this waste stream is to use chains instead of kiln sticks. The amount of these different toxic waste streams generated depends on the operating practices and level of productivity at any particular plant. For example, the sludge buildup in treating cylinders varies. Some cylinders may require annual cleaning, generating as little as a drum of waste to many drums. The practice of sanding areas, or poorly designed trams with low-hanging undercarriages, can drag materials into and out of treating cylinders as well as cause accumulation. If the wood to be treated contains a lot of surface dirt, grit, and sawdust, these materials become contaminated and accumulate, causing a significant sludge management problem over time. Poor housekeeping practices can also contribute to toxic sludge accumulation. Studies made of the Koppers Grenada Tie Treating Plant in Mississippi, the

46

Handbook of Pollution Prevention and Cleaner Production

Somerville Tie Plant in Texas, and several others show that, historically, woodtreating plants had horrendous housekeeping problems. Creosote coal tar spills generally occurred on a daily basis, with plants only beginning to account for these incidental spills through monitoring and improved housekeeping practices beginning in the early to mid-1990s. The single-most operational and technological change that has improved housekeeping and reduced sludge management has been statutory requirements for installing and maintaining drip pads (described later in this chapter). Quality control also plays a major role in toxic waste reduction. Facilities that do not have formal ISO 9001 quality assurance for their products generally face the risk of high levels of rejects or off-spec production. If some of the off-spec production or waste is attributed to the treatment part of the process then solid wastes can add up over time to significant levels. To illustrate the magnitude of wastes that can build up over time the following is an analysis of the Somerville Tie Plant. This facility is currently one of the largest wood-treating plants in the world. Up until the 1980s it was touted as the largest plant in the USA. Because the facility made railroad ties at high production rates, it handled very large quantities of raw materials (wood) and chemicals. Large production volumes of any product imply that even when small quantities of wastes are produced as by-products from manufacturing, the quantities of wastes can become significant over time. By way of a simple analogy, if a secretary makes one mistake in the preparation of a document then there is a single page in that one document that becomes waste. If there are 20 secretaries that make one mistake in each of the documents they prepare, then there are 20 waste pages that enter the trash. If the workforce or the number of documents handled increase by fivefold and there are the same or similar mistakes in each document, then there are 100 pieces of waste paper that must be disposed of. The focus of ISO 9000 is to quantify defects, identify the causes for defects, and then to devise corrective actions aimed at reducing inefficiencies in order to improve quality and productivity. Fifteen to twenty years ago the Somerville Tie Plant did not have nor did it rely on ISO 9001 quality control and assurance practices. At the same time, wastes were not monitored or accounted for, and hence the operators of the facility did not have an understanding of the magnitude of waste generated at any point in time. The following references are a few publications that document how wastes are generated from poor quality control practices:     

The Benefits of ISO 9000 (http://www.scribd.com/doc/7600435/Benefits-of-ISO9000) Introduction to ISO 9000 (http://www.qualityservices.ca/Selling9K-2l.pdf) Article in Quality Digest magazine (http://www.qualitydigest.com/dec06/articles/ 03_article.shtml) Bendavid-Val and Cheremisinoff (2001) Cheremisinoff (2001).

Pollution and pollution controls

47

Using the production records for tie insertions, the number of defective ties that may have been produced due to the lack of an ISO 9001 program, assuming conservatively that only 2% of production was lost from poor handling practices and derailments, was calculated. The number of defective ties was then converted to a mass basis using the standard dimensions and weight of a railroad tie. These calculated defects are as follows: 







Between 1960 and 1969 the facility made approximately 8,275,000 ties. At a 2% defect rate, the number of defective ties was 165,500 over that 10-year period. This is equivalent to 14,895 tons of treated scrap wood. A daily average based on this calculation is 4.1 tons of waste. Between 1970 and 1979 the facility made approximately 15,150,000 ties. At a 2% defect rate, the number of defective ties was 303,000 over that 10-year period. This is equivalent to 27,270 tons of treated scrap wood. A daily average based on this calculation is 7.5 tons of waste. Between 1980 and 1989 the facility made approximately 12,860,000 ties. At a 2% defect rate, the number of defective ties was 257,200 over that 10-year period. This is equivalent to 23,148 tons of treated scrap wood. A daily average based on this calculation is 6.3 tons of waste. Between 1990 and 1994 the facility made approximately 5,965,000 ties. At a 2% defect rate, the number of defective ties was 119,300 over that 5-year period. This is equivalent to 10,737 tons of treated scrap wood. A daily average based on this calculation is 5.9 tons.

In total, the number of rejects is equivalent to 281 miles of track (there are approximately 3000 ties per mile of track that is laid), which is more than the distance from Washington, DC to New York City. The average over the entire 34 production years examined is 5.9 tons per day of treated wood scrap just from rejected, damaged, and defective treated railroad ties. By way of further examples, Figure 3.2 shows a relatively small pile containing approximately 11 reject or damaged ties. This is equivalent to more than 1 ton of

Figure 3.2 A pile of scrap ties making up a total of more than a ton of waste.

48

Handbook of Pollution Prevention and Cleaner Production

Figure 3.3 Rejects making up a total of more than 5 tons of waste.

treated scrap; Figure 3.3 shows a photograph of a pile of treated scrap at another treating plant. There is over 5 tons of waste in this small pile. Even if the estimates made above are off by a factor of 2 or 3, the quantities of solid wastes generated represent a formidable amount of waste material to manage. Additionally, these types of wastes lead to the generation of other waste streams. Rejects generated during treatment can cause the facility to try to salvage damaged or off-spec production lots by cutting, reshaping, and dapping cut ends of treated wood articles. The scrap created during post-treatment represents additional treated waste. Well-run plants today do not generally generate such large quantities of scrap. Many facilities in more modern times have adopted ISO 9000 and have certified their products under an ISO 9001 quality assurance program. Twenty or more years ago, there was a very different situation, with facilities generally creating large amounts of solid waste and allowing irresponsible poor housekeeping practices to contaminate soil, groundwater, and surface water run-off (see Figures 3.4 and 3.5 for examples from years gone by, showing poor operating conditions). The historical photographs shown help the reader to appreciate how environmentally damaging the industry was until RCRA enforcement actions took hold, beginning in the mid to late 1980s.

3.2.2

Liquid wastes

In addition to solid and semi-solid wastes such as sludge, wood-treating plants generate significant amounts of wastewater. Freshly cut and green wood contains excess moisture that must be removed before it is suitable for treatment. The process of removing moisture is referred to as seasoning. Green timber may contain sizeable amounts of water. Rietz (1957) reported that a southern pine log 16 feet long and 15 inches in diameter may contain 70 gallons of water; a white oak log 16 feet long and 18 inches in diameter with 3-inch sapwood may

Pollution and pollution controls

49

Figure 3.4 Photograph obtained from the Somerville Texas Historical Society of the Somerville Tie Plant in the 1940s or earlier.

contain 126 gallons or 1050 pounds of water. On a weight basis the latter figure represents 56.7% of the total weight of the log. Wood in service will eventually assume a moisture content level that is proportional to or consistent with the relative humidity of its surroundings. In other words, wood will absorb moisture from the atmosphere (i.e. it is

Figure 3.5 Photograph obtained from the Somerville Texas Historical Society of the Somerville Tie Plant in the 1920s.

50

Handbook of Pollution Prevention and Cleaner Production

hygroscopic) until the vapor pressure of the water in the wood balances the partial pressure of the water vapor in the surrounding air. The equilibrium moisture content varies with climatic conditions. Hence, wood left to season naturally only reaches an equilibrium level of moisture with the surrounding atmosphere and hence still contains significant amounts of water at the time of treatment. Removal of free water (i.e. sap) from cell cavities has little effect on the wood properties other than to reduce its unit weight. Removal of ‘‘imbibed’’ or hygroscopic moisture from the cell walls affects both physical and mechanical properties. The free water is removed first during seasoning since energy needed to break hygroscopic bonds is completely used to evaporate free water from the surface of the wood. The moisture content at which all free water is removed from cell cavities but none of the hygroscopic moisture from the cell walls, is called the ‘‘fiber saturation point’’. For many wood species the fiber saturation point occurs at a moisture content of roughly 25–30%. Moisture in this case is expressed as a percentage of the oven dry weight of the wood. Wastewater generation at a plant depends not only on the treating technology used, but also on the moisture level of the wood at the time of treatment. Seasoning costs money. If the wood is seasoned in a kiln, there is a cost for energy. If the wood is chemically seasoned, as with naphtha in a Boulton-type process, there is both the cost for chemicals and fuel for energy. And if wood is seasoned naturally in a stockyard, there is the cost to maintain inventories for 12–14 months, with additional costs incurred because some of the stockpile will spoil or rot in the field. The optimum moisture level for treating wood varies

Figure 3.6 Aeration ponds, which are a primary treatment site for an on-site wastewater treatment plant at a wood-treating facility.

Pollution and pollution controls

51

among facilities and generally considers a trade-off between product quality and costs. During the treatment process, the treating chemicals (creosote coal tars and pentachlorophenol) displace some of the wood’s remaining moisture, thus generating a wastewater stream containing sap water and treating chemicals. Additionally, during the final vacuum stage of the treating cycle, vapors withdrawn from the retorts are generally condensed adding to the wastewater stream. (Note, with arsenicals like chromated copper arsenate (CCA), water is used as a part of the process and is recycled back through treating cylinders through a make-up tank; hence no wastewater is generally created.) Modern treating plants manage wastewater in on-site wastewater treatment works. These generally tend to be primary treatment works that allow facilities to discharge the effluent to a municipal sewer system (see Figure 3.6). Most of these systems did not come into operation at wood-treating plants in the USA until the late 1980s. Prior to this, wood-treating plants managed wastewaters in unlined earthen pits, generally recovering a portion of creosote coal tars and oils by skimming and recycling. These were very crude and inefficient recovery systems. Such impoundments were not maintained and often overflowed, introducing contaminated water into surface water run-off and into groundwater. Figures 3.7–3.10 are photographs taken at a wood-treating facility in Louisiana ca. mid-1980s before surface impoundments were closed under the RCRA. They help to illustrate the poor and environmentally damaging practices used by some facilities during that time period. Figure 3.11 is a photograph taken in more recent times, showing environmental problems still persist but clearly not to the extent of the pre-1990 era. Some facilities historically used land farming to attempt to dispose of wastewater as a low-cost technology. As an example, pentachlorophenol (PCP) has a tendency to biodegrade. The addition of lime and tilling for aeration aids in

Figure 3.7 Photograph of a surface pond at a Louisiana wood-treating plant during the mid-1980s. Ponds were used to contain wastewater contaminated with creosote and pentachlorophenol.

52

Handbook of Pollution Prevention and Cleaner Production

Figure 3.8 Photograph of a drainage way from a surface pond at the same Louisiana wood-treating plant during the mid-1980s.

the biodegradation of the PCP. This practice, however, was found to be environmentally unfriendly because the breakdown of PCP was not complete and studies on experimental programs did not confirm the elimination of dioxins and other carcinogenic compounds contained in the commercial chemical. The practice did little more than create multiple pathways for pollution because it aggravated contamination of groundwater and surface water run-off as well as introduced air emissions at facilities.

Figure 3.9 Photograph of a surface pond at the same Louisiana wood-treating plant during the mid-1980s. The facility managed its wastewater in an earthen pond and claimed it was a water treatment works because it skimmed creosote coal tars from the pond and recycled it.

Pollution and pollution controls

53

Figure 3.10 Photograph of the same facility’s surface pond from the 1980s. Notice the heavy tar contamination along the banks of the pond.

An equally serious problem, more so from a historical practices viewpoint, is drippage. When treated wood is removed from a retort it is warm and coated with the treating chemicals. While a final vacuum is applied to the cylinder to help remove condensable vapors, this stage is not 100% efficient in the recovery of residual chemicals. Consequently, freshly treated wood when immediately removed from the treating cylinder has a tendency to drip. The drippings are referred to as kickback.

Figure 3.11 Photograph taken in 2008 at a wood-treating plant in Louisiana showing pond area contaminated with creosote coal tar.

54

Handbook of Pollution Prevention and Cleaner Production

Studies at the Koppers Grenada Tie Treating Plant in Mississippi reported kickback as much as 2 or more pounds of chemicals per thousand cubic feet of wood treated. The historical practice at wood-treating plants was to allow this kickback to accumulate on bare ground along the track areas in front of cylinders and in stockyards. Decades of this practice contributed to significant levels of groundwater contamination that have migrated off-site into communities and in surface water run-off. The practice was gradually eliminated in the early 1990s with the introduction of mandatory requirements for treating facilities to use drip pads. Drip pads have virtually eliminated the problem of kickback at the treatment platform. Placing this in a little better context, it was not until 1990 that the US Environmental Protection Agency (EPA) listed wastes from wood-preserving processes as hazardous. After this recognition or legal definition for woodpreserving wastes as hazardous, facilities were required to install concrete pads, called drip pads. Drip pads facilitate the handling of these wastes. There are design and operating standards for drip pads used to manage these hazardous wastes. These standards are briefly described later in this chapter. While the use of drip pads has contained and controlled spillage and kickback at the treatment platform, these same standards do not apply to stockyards. The combination of enforcement of spill prevention and contingency plans and drip pads are essential tools for preventing the recurrence of historical environmentally damaging practices. These facilities in general handle many millions of pounds of chemicals on a yearly basis. The use of high production volumes generally leads to incidental spills that must be managed aggressively (see

Figure 3.12 Spill on drip pad area. Maintaining the drip pad free from cracks and surface deterioration is crucial to containing incidental spills.

Pollution and pollution controls

55

Figure 3.13 Providing berms around stockpiled treated wood stock helps to spread contamination from kickback.

Figures 3.12 and 3.13, which again emphasize that site contamination problems and the potential for air, surface, and groundwater emissions are ever-present at these plants).

3.2.3

Air emissions

There are multiple sources of air emissions from wood-treating plants. Examples are shown in Figures 3.14–3.24, and include:       

fugitive vapor emissions from leaking piping aperture; fugitive dust from heavy machinery traffic; point source emissions from the stacks of boilers; air emissions from cylinder venting episodes; fugitive air emissions from the opening of treating cylinder doors; off-gassing from the surfaces of freshly treated wood; vaporization losses from treated wood stored in on-site stockyards.

Individually these emission sources may represent small mass quantities of emissions of harmful chemicals, but cumulatively they are sizeable and subject to varying intensities depending on both seasonal conditions and production levels. Air emissions are viewed as being the more problematic issues at woodtreating facilities because by and large they are not controlled nor has the

56

Handbook of Pollution Prevention and Cleaner Production

Figure 3.14 Leaking valve where semi-volatile and volatile chemicals evaporate into the atmosphere, creating air pollution.

industry sector made reasonable efforts to accurately quantify them. Separate discussions are presented later in this chapter and in a subsequent chapter.

3.3 Drip pads Drip pads are hazardous waste management units that are unique to the woodpreserving industry. The history of drip pads is closely linked to the EPA’s decision to list wood-preserving process wastes as hazardous. The wood-preserving

Figure 3.15 An equipment component leak that contributes to air emissions from the volatilization of semi-volatile and volatile chemicals.

Pollution and pollution controls

57

Figure 3.16 Another example of leaking piping aperture, which contributes to air emissions from the volatilization of semi-volatile and volatile chemicals.

industry uses a standard process to produce treated wood products that are resistant to natural decay. The following discussion is taken from the EPA standard (US EPA, 2001). Fresh lumber is treated with a preservative solution and then placed on a concrete pad, where it remains until any excess solution not absorbed by the wood has stopped dripping. Once the dripping stops, the wood is transferred to a storage yard and all excess preservative that has dripped on to the drip pad is removed as waste.

Figure 3.17 Fugitive emissions resulting from the opening of cylinder doors during the removal of treated wood.

58

Handbook of Pollution Prevention and Cleaner Production

Figure 3.18 Closeup shot of fugitive emissions resulting from the opening of cylinder doors during the removal of treated wood.

On 6 December 1990, the EPA promulgated regulations listing certain woodpreserving process wastes as hazardous (55 FR 50450). The listings specifically include wastewaters, process residuals, preservative drippage, and spent formulations from wood-preserving operations using chlorophenolic formulations (F032), creosote formulations (F034), and inorganic preservatives containing arsenic or chromium (F035). Once the EPA listed these wastes as hazardous, the concrete pads typically used for collecting the drippage became subject to regulation under RCRA Subtitle C as hazardous waste management

Pollution and pollution controls

59

Figure 3.19 Off-gassing of semi-volatile emissions from surfaces of freshly treated wood.

units. Since the drip pads had never been regulated and did not resemble any of the existing hazardous waste management units (e.g. tanks or containers), there were no protective regulations for drip pad owners and operators to follow. To ensure proper waste management, the EPA developed unit-specific standards for the design, installation, operation, and closure of drip pads at the same time as the new wood-preserving listings were promulgated. A hazardous waste drip pad is a non-earthen structure consisting of a curbed, free draining base that is designed to convey excess preservative drippage, precipitation, and surface water run-on from treated wood operations to an associated collection system. Drip pads, as defined in x260.10, are exclusive to the wood-preserving industry. Preservative solutions are commonly applied to

Figure 3.20 Fugitive dust emissions in a stockyard. Soil that has become contaminated from drips and kickback are attrited and become airborne when heavy machinery runs over contaminated areas.

60

Handbook of Pollution Prevention and Cleaner Production

Figure 3.21 Photograph of tankage at a wood-treating plant. The vents on tanks are a point source of breathing and working losses of chemicals.

wood products using a pressure-treating process. Once the preservative solution has been applied to the wood, it is removed from the process unit and excess solution is allowed to drip from the wood on to drip pads. As a result of this process, excess solution dripping from the wood becomes a solid waste and,

Figure 3.22 A wood-fired boiler for generating steam at a wood-treating plant. Generally combustion systems are an appropriate technology for managing wastes unless they are used to burn toxic sludge and treated wood without proper combustion and air pollution controls.

Pollution and pollution controls

61

Figure 3.23 Treated poles laid out to dry. The larger the surface area of exposure, the greater the mass emissions of chemicals.

depending on the type of preservative used, a hazardous waste. A drip pad is used solely for the collection and temporary accumulation or storage of excess wood preservative prior to its removal from the unit. Regulated drip pads will be found only at wood-preserving facilities. The design standards for hazardous waste drip pads are codified in xx264.573 and 265.443. Drip pads must be designed and constructed of non-earthen materials that have enough structural strength to prevent failure of the unit under the weight of the waste, preserved wood products, personnel, and any moving equipment used in wood-preserving operations. The remainder of the

Figure 3.24 Stacked treated ties. The free surfaces of the ties are exposed to the atmosphere and are a source of continual air emissions.

62

Handbook of Pollution Prevention and Cleaner Production

drip pad design requirements is specifically intended to control the liquid and semi-liquid wood-preserving wastes that are stored or accumulated on the drip pad. To prevent wastes from running over the edges of the flat drip pad surface, the unit must be constructed with a raised curb or berm around the perimeter of the pad. In order to simplify removal of wastes from the drip pad, the surface must be sloped toward a collection unit, such as a sump. Unless this collection unit has enough capacity to hold precipitation run-on and preservative drippage, or unless the pad is protected from precipitation (e.g. indoors or covered), a storm water run-on and run-off control system must be used. All new and existing drip pads must be in compliance with these design criteria. Additional drip pad design standards include measures to prevent infiltration of liquid waste into or through the unit’s structure. Impermeable sealers, coatings, or covers can reduce the quantity of waste absorbed into the unit itself. Infiltration protection, especially for porous materials like concrete, is important because when liquid wastes migrate into the structure, the likelihood of an uncontrolled release into the environment increases. As a result, drip pads will be more susceptible to cracking and deterioration, and removal of all wastes from the unit becomes more difficult. Because absolute impermeability is not feasible, the EPA introduced a performance standard for permeability of the surface coating in the regulations. In general, the required level of protection can be achieved using most of the sealers, coatings, and covers commercially available. The EPA intends the drip pad design standards to prevent migration of waste from the unit into the surrounding environment. Provision of an underlying synthetic liner and leak detection system can prevent waste migration into adjacent subsurface soil, groundwater, or surface water. No specific permeability criteria are designated for a drip pad liner, but the unit’s leak detection system must be able to signal releases from the pad at the earliest practicable time. For all pads constructed after 24 December 1992, the EPA also mandates the installation of a leak collection system to remove wastes accumulating on the synthetic liner. In addition, any sumps or other collection devices used in association with a hazardous waste drip pad are regulated as hazardous waste tanks, and the owner and operator of the unit must comply with all applicable provisions in Subpart J of Part 264/265. When the regulations were first promulgated, a new drip pad was required to conform to the standards for both surface impermeability and liners and leak detection. Since that time, the EPA has revised the drip pad management standards; now owners and operators of new drip pads may choose between these two options. The EPA does not recommend one option over the other, but believes that, in the long run, installation of a liner and leak detection system will require less maintenance and be less costly than repeated applications of surface coatings. Prior to use for hazardous waste management, the owners and operators of new drip pads must implement one of the design options. All existing drip pads (i.e. drip pads that were constructed or for which a binding contract was made prior to 6 December 1990) must be sealed, coated, or covered with an impermeable

Pollution and pollution controls

63

material meeting regulatory specifications. An existing drip pad that already has a surface coating will need no further upgrading to comply with federal standards. An existing unit that is upgraded to include a liner and leak detection system is no longer subject to the surface coating requirements. Before such an upgrade is completed, however, the owner or operator must develop and submit a written plan for modifying the unit to the Regional Administrator. The plan must include a description of all proposed repairs and upgrades, as well as a schedule by which modifications will be made. An independent, qualified, registered, professional engineer must certify that the proposed plan will bring the drip pad into compliance with all applicable liner, leak detection, and leak collection standards (xx264.571/265.441). A drip pad must be maintained free of cracks and show no signs of corrosion or other forms of deterioration. Drip pads must also be cleaned frequently to allow for weekly inspections of the entire drip pad surface without interference from accumulated wastes and residues. The manner and frequency of cleaning required is determined on a case-by-case basis. The facility’s operating log must document the date, time, and method of each cleaning, and all cleaning residues must be managed as hazardous wastes under RCRA Subtitle C. In addition to occasional cleaning, drippage and precipitation must be emptied into a collection system as often as necessary to prevent waste from overflowing the curb around the perimeter of the unit. All collection tanks must be emptied as soon as possible after storms to ensure that sufficient containment capacity is available to accommodate continued run-off. Three types of inspections are required for drip pads. First, an existing drip pad must be inspected to ensure that the unit is still protective of human health and the environment, and thus fit for continued use. Until the unit is in full compliance with the current standards, an independent, qualified, registered, professional engineer must prepare an annual written assessment of the drip pad’s integrity. Each assessment must document the extent to which the drip pad meets current design and operating standards (xx264.571/265.441). Second, xx264.574/265.444 require newly installed or upgraded existing drip pads to be inspected to verify that the unit was properly constructed and that no damage occurred prior to use. During this inspection, an independent, qualified, registered, professional engineer must certify that the drip pad achieves all applicable design standards in xx264.573/265.443. Finally, all new and existing drip pads must be inspected weekly and after storms to ensure that the units and their associated liquid collection systems are functioning properly and to detect any deterioration of or leaks from the units. Upon inspection, if a drip pad shows any deterioration, the affected portion of the unit must be removed from service for repairs in accordance with specified procedures. If hazardous wastes have been released into the environment, all appropriate cleanup measures must be taken, and the release may be reportable under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and the Emergency Planning and Community Right-to-Know Act (EPCRA).

64

Handbook of Pollution Prevention and Cleaner Production

Figure 3.25 Drip pad at a pole-treating facility.

Figure 3.25 shows a closeup photograph of a drip pad at a pole-treating facility. Figure 3.26 shows the wastes from a drip pad being placed into drums and manifested for off-site shipment to a disposal facility. The introduction of drip pads to the wood-preserving industry dramatically improved housekeeping and waste management practices. Drip pad standards do not necessarily apply to treated wood stockyards. There are no examples where the use of such pads has been found at operating facilities. Stockyards are still a source of kickback; however, provided the operator has a monitoring program that identifies and immediately cleans up drips, the need for drip pads is considered discretionary by the EPA.

Figure 3.26 Wastes from a drip pad being placed into drums and manifested for off-site shipment to a disposal facility.

Pollution and pollution controls

65

3.4 Fate and transport When released to groundwater, coal-tar creosotes form non-aqueous-phase liquids (NAPLs). These NAPLs tend to be a long-term source of dissolvedphase organic plumes in groundwater. NAPLs that are present in the subsurface at saturations significantly above their residual saturation can be removed by enhanced recovery technologies; however, NAPLs that are at or below their residual saturations are trapped in the formation and are not readily recoverable. The long-term management of dissolved plumes originating from a coal-tar creosote source is a technical challenge. For some sites stabilization of the source may be the best practical solution to decrease the contaminant mass loading to the plume and associated off-site migration. At the bench scale, the deposition of manganese oxides, a permanganate reaction by-product, has been shown to cause pore plugging and the formation of a manganese oxide layer adjacent to the non-aqueous phase liquid creosote, which reduces post-treatment mass transfer and hence mass loading from the source (Thomson et al., 2008). The alternative approach to residual NAPL recovery described is an example of in situ NAPL management. In situ chemical oxidation for source area stabilization entails the use of a permanganate chemical oxidizer that is flushed through an aquifer zone containing residual NAPLs. The oxidant is not meant to remove NAPL mass entirely. Rather, as the oxidant migrates through the targeted source area, (bio)geochemical reactions between the organic constituents of interest (COIs) and the oxidant cause the destruction and stabilization of NAPL via a two-step process: (i) oxidation and (ii) dissolution. The biochemical oxidation processes destroy COIs present in the dissolved phase, thereby increasing the dissolution of COIs from the NAPL into the groundwater. The more water-soluble, lower-molecular-weight NAPL constituents are then released and chemically oxidized at a proportionally higher rate, thus leading to a ‘‘hardening’’ or chemical ‘‘weathering’’ of the residual NAPL mass. The selective removal of the more labile constituents causes a net increase in the viscosity of the NAPL, yielding a more stable NAPL source that is less susceptible to dissolution processes. In addition, the oxidation reaction precipitates manganese dioxide (MnO2) and results in the formation of a chemical ‘‘shell’’, which further isolates the ‘‘weathered’’ NAPLs. As such, the flux of COIs into the dissolved phase is decreased, allowing natural attenuation processes to more effectively manage COI plumes (http://www.adventusgroup.com/projects/proj_ isbs_beazer.shtml). Creosote in soils will tend to persist for decades, especially where there is high organic or sediment content. Since the 1970s there have been numerous studies aimed at developing low-cost remediation practices such as bioremediation through land farming and various groundwater bidegradation technologies. These studies have shown varying degrees of success, but none has proven to be universal.

66

Handbook of Pollution Prevention and Cleaner Production

A study by Mueller et al. (1991) used shake-flask studies to examine the rate and extent of biodegradation of PCP and 42 components of coal-tar creosote present in contaminated groundwater recovered from the American Creosote Works Superfund site, Pensacola, FL. The ability of indigenous soil microorganisms to remove these contaminants from aqueous solutions was determined by gas chromatographic analysis of organic extracts of biotreated groundwater. Changes in potential environmental and human health hazards associated with the biodegradation of this material were determined at intervals by Microtox assays and fish toxicity and teratogenicity tests. After 14 days of incubation at 30 C, indigenous micro-organisms effectively removed 100%, 99%, 94%, 88%, and 87% of measured phenolic and lower-molecular-weight PAHs and S-heterocyclic, N-heterocyclic, and O-heterocyclic constituents of creosote respectively. However, only 53% of the higher-molecular-weight PAHs were degraded, and PCP was not removed. Despite the removal of a majority of the organic contaminants through biotreatment, only a slight decrease in the toxicity and teratogenicity of biotreated groundwater was observed. Data suggest that toxicity and teratogenicity are associated with compounds difficult to treat biologically and that one may not necessarily rely on indigenous microorganisms to effectively remove these compounds in a reasonable time span; to this end, alternative or supplemental approaches are necessary. The investigators concluded that similar measures of the toxicity and teratogenicity of treated material may offer a simple, yet important, guide to bioremediation effectiveness. In addition to possible human and food chain contact with creosote and PCP from contaminated groundwater and soils, there is concern about workers at wood-treating plants and neighboring communities coming into contact with air pollution. While a likely pathway for exposure to airborne contaminants from the suspension of contaminated soils may result in ingestion, the AWPI (American Wood Preservers Institute) and industry members have often argued that the vapor pressures of the constituents found in creosote along with PCP are so low that volatilization of any appreciable amount that could cause adverse health effects is improbable. As discussed in the next chapter, the industry has promulgated this unsubstantiated claim by creating calculations for air emissions estimates that dramatically under-report mass emissions from treated wood surfaces. To understand this pathway of exposure better, we need to consider the process of vaporization. McDermott (2006) states ‘‘the higher the vapor pressure, the higher the airborne concentration possibility’’. Volatile compounds have vapor pressures greater than 1 mmHg (133.32 Pa) at ambient temperature and exist entirely in the vapor phase when airborne. As examples, benzene and toluene have vapor pressures well above 1 mmHg. A comparison of the vapor pressures of these pure chemicals shows that benzene is 3.8 times more volatile than toluene at normal (ambient) temperature and pressure conditions (vapor pressure of benzene ¼ 13.172  103 Pa at 25 C; vapor pressure of toluene ¼ 3.4664  103 Pa at 25 C; ratio of vapor pressures ¼ 13.172  103 Pa/3.4664  103 Pa ¼ 3.8). These chemicals are known as volatile organic compounds (VOCs).

Pollution and pollution controls

67

PAHs are semi-volatile chemicals. Mackay et al. (1999) noted that ‘‘semivolatile compounds have vapor pressures of 107 to 1 mmHg and can be present in both the vapor and particle state’’. They further noted that ‘‘nonvolatile compounds have vapor pressures of less than 107 mmHg and are found exclusively in the particle-bound state when in air’’. Many PAHs undergo sublimation. Sublimation is the term for when matter undergoes a phase transition directly from a solid to a gaseous form, or vapor, without passing through the more common liquid phase between the two. It is a specific case of vaporization. The best-known example of a material that undergoes sublimation is dry ice, or frozen carbon dioxide. PAHs behave in the same manner. These facts mean that although PAHs are characterized as having low vapor pressures, they are still volatile. Furthermore, vapor pressure is temperature dependent. Any chemical’s vapor pressure, and hence its volatility, depends on temperature. When treating chemicals are applied to treat wood, they coat the surface of the wood and are thus subject to volatilization. Additionally, chemicals that impregnate the fibrous pore structure of the wood are not chemically bound to wood fibers but rather are trapped within the porous structure. It is well known that these chemicals will diffuse to the surface of the wood and then evaporate. Like vaporization, the diffusion process is temperature dependent, and hence the higher the temperature of the treated wood, the greater the mass flux or rate of diffusion to the surface. Wood that undergoes pressure treatment is generally at temperatures between 190 F (360 K) and 210 F (372 K) or above. When treated wood is removed from the retort it is at an elevated temperature. The consequence is that the PAHs contained in creosote coal tars have higher vapor pressures and are more volatile than when they are at ambient temperature conditions. When treated wood is held on a drip pad, the process of volatilization slows down compared to the point at which it is first removed from the cylinder because the wood begins to cool, but this process takes many hours. Wood may be held at a drip pad for up to 24 hours, during which time off-gassing occurs. The US EPA’s AP-42 notes that the diffusional process by which PAHs migrate to the surface and then volatilize into the atmosphere increases during the first several days, but then begins to slow down. Emissions have been reported to continue for up to 90 days, but thereafter the rate of volatilization is low and remains relatively constant. When treated wood is stored in stockyards, the treated poles are exposed to sunlight. While the ambient air temperature may be temperate, surfaces that are exposed to direct sunlight will reach temperatures that can be 40 C or more higher than ambient air depending on the time of day and the angle at which sunlight strikes their surfaces. A study by the US Forest Service (1963) on skin temperatures of wooden surfaces exposed to direct sunlight reported temperatures as high as 170–179 F (350–355 K) on exposed roof shingles. Such temperature levels are generally exceptions but may last an hour or more each day, with more typical temperatures of 160–169 F (344–349 K) for 20 hours

68

Handbook of Pollution Prevention and Cleaner Production

and 150–159 F (339–344 K) for 43 hours. When treated wood is subjected to these elevated temperatures, the vapor pressures of the PAHs are raised and they become more volatile than under ambient conditions. The above discussion explains why considering volatilization at the temperatures in which wood is treated and handled is important to air emissions. Figure 3.27 provides a plot of literature-reported values of vapor pressures for different PAHs and PCP. The data plotted in this figure are on semi-logarithmic coordinates of vapor pressure versus the inverse of absolute temperature. Each chemical shows a linear relationship on this plot. Because the relationships are linear, they can be empirically fitted to an equation. This equation is known as the Clausius–Clapeyron relation and has the general form: lnðPÞ ¼ Hvap =Rð1=Tex Þ þ c

(3.1)

where P ¼ vapor pressure (Pa), Tex ¼ temperature (K), Hvap ¼ heat of vaporization, and R ¼ universal gas constant expressed in the appropriate units of measurement. Moore (1962) and others demonstrated this relationship as an equation of state more than 40 years ago and have proven that careful measurements of vapor pressure of any chemical at different temperatures can be used to estimate

10,000.0000 1,000.0000 100.0000

VAPORPRESSURE (Pa)

10.0000 1.0000 0.1000 0.0100 0.0010 0.0001

ACENAPHTHYLENE ACENAPHTHENE FLUORENE PYRENE BENZO[A]PHENANTHRENE 9,10-BENZOPHENANTHRENE

0.00001

ANTHRACENE BENZO[A]PYRENE

0.000001

PERYLENE FLUORANTHENE

0.0000001

PENTACHLOROPHENOL NAPHTHALENE

0.00000001 0.0015

0.0020

0.0025

0.0030

0.0035

1/T (K)

Figure 3.27 Vapor pressure–temperature data from the literature.

0.0040

Pollution and pollution controls

69

its heat of vaporization. A material’s heat of vaporization is defined as the amount of heat required to convert a unit mass of a liquid at its boiling point into vapor without an increase in temperature. Table 3.1 provides linear regression fits of the data plotted in Figure 3.27. The parameters provided in the table allow application of equation (3.1) to calculate vapor pressures. These correlations are considered further in the next chapter for estimating emission factors. Figure 3.27 helps to illustrate that the most volatile chemical is naphthalene. The chemical’s odor is generally what is smelled by neighborhoods in close proximity to wood-treating plants. Even at room temperature this chemical readily sublimates and gives off a characteristic odor, which is detected at a very low odor threshold. The figure also shows that vapor pressures vary significantly over temperature and, hence, relying on an ambient reference state temperature to arrive at a conclusion that mass emissions of PAHs are too low to pose potential health risks is not reasonable.

3.5 Case studies Since 1980, the EPA has classified 56 wood-preserving sites as Superfund sites. At about 40 of these sites, the EPA has completed the process of selecting a cleanup strategy for the soil, sludge, sediments, and water contaminated by wood treatment wastes. The EPA’s process for selecting a cleanup strategy at a Superfund site is described in the record of decision (ROD), which summarizes the basis for the decision and describes the remedial strategy. The EPA’s work with wood-treating sites has generated about 47 RODs for 40 such sites.

3.5.1

Koppers Wood Treating Company (a.k.a. Koppers Company Incorporated Forest Production Group), Carbondale, Jackson County, IL (http://www.atsdr.cdc.gov/HAC/PHA/kopperswood/ kwt_p1.html#back)

The site occupies about 136 acres along North Marion Street on the northeastern edge of Carbondale in Jackson County. Land surrounding the site is used for residential, agricultural, commercial, and industrial purposes. An abandoned railroad track borders the southern edge of the site. The nearest homes are immediately south of the track at the western end of the facility. A combination of cultivated, undeveloped, and wooded land is north and east of the site. Only a few rural residential dwellings are scattered throughout the immediate area. An Illinois Central Railroad yard is on the land west of the Koppers facility. The site was a wood-treating facility that began operation in 1905. It was formerly one of the world’s largest creosote treatment plants. The site remained active until July 1991. A similar Koppers facility near Galesburg, IL, is listed on the federal National Priorities List (NPL).

Chemical

Hvap/R

c

Temp. range (8K)

Coefficient of fit

Fluorene

10,602.9

32.869

298–324

0.9978

Merk Index; Handbook of Chemistry and Physics, 49th ed.; Goldfarb and Suuberg (2008)

Acenaphthylene

8928.2

29.336

297–320

0.9769

Merk Index; Handbook of Chemistry and Physics, 49th ed.; Goldfarb and Suuberg (2008)

Acenaphthene

9462.4

30.566

297–316

0.9999

Merk Index; Handbook of Chemistry and Physics, 49th ed.; Goldfarb and Suuberg (2008)

Pyrene

12,295.1

33.414

298–381

0.9994

Merk Index; Handbook of Chemistry and Physics, 49th ed.; Goldfarb and Suuberg (2008)

Benzo[a]phenanthrene

13,218.2

31.416

372–409

0.9966

Goldfarb and Suuberg (2008)

9,10-Benzophenanthrene

14,622.7

35.685

368–399

0.9985

Goldfarb and Suuberg (2008)

Anthracene

11,708.6

32.294

298–418

1.0000

Merk Index; Handbook of Chemistry and Physics, 49th ed.; Goldfarb and Suuberg (2008)

Benzo[a]pyrene

14,174.5

33.493

298–424

0.9987

Merk Index; Handbook of Chemistry and Physics, 49th ed.; Goldfarb and Suuberg (2008)

Perylene

15,535.3

35.540

298–432

0.9987

Merk Index; Handbook of Chemistry and Physics, 49th ed.; Goldfarb and Suuberg (2008)

Fluoranthene

12,583.9

35.130

298–359

0.9982

Merk Index; Handbook of Chemistry and Physics, 49th ed.; Goldfarb and Suuberg (2008)

Pentachlorophenol

12,583.9

12.265

273–582

0.9693

Merk Index; Handbook of Chemistry and Physics, 49th ed.

Naphthalene

ln(p) ¼ 10.0896  2926.61/ (t þ 237.332) p ¼ vapor pressure (torr), t ¼ temperature ( C)

0.9999

Fowler et al. (1968)

70

Table 3.1 Best-fit correlations for vapor pressures of PAHs and pentachlorophenol

Data sources

Handbook of Pollution Prevention and Cleaner Production

Pollution and pollution controls

71

Three off-site environmental incidents have been reported in the history of the facility: 





In 1939, creosote was reportedly diverted into a wastewater lagoon at the eastern portion of the site by a northern drainage ditch to prevent a fire. Heavy rains then caused a breach of the lagoon berm, spilling wastewater, creosote, and sludge into an off-site spill area and Glade Creek. In the summer of 1962, a fish kill occurred in the Big Muddy River due to phenol poisoning. The cause of this incident was traced to an apparent overflow of a lagoon at the Koppers site. Koppers and the Illinois Department of Conservation agreed to an out-of-court settlement for restocking the river. In 1981, two cows grazing on land next to the Koppers wood-treating site died. An autopsy on one of the two deceased cows revealed the cow had ingested creosotecontaining material. This incident led to the IEPA (Ilinois Environmental Protection Agency) conducting a preliminary remedial investigation at the Koppers site.

The variety of wood-treating products used during facility operation included:      

grade 1 creosote – undiluted creosote; 60–40 creosote – 60% creosote and 40% coal tar; PCP – 7.5% pentachlorophenol in fuel oil; fluoro–chrome–arsenate–phenol (FCAP) – mixture of sodium fluoride, sodium arsenate, sodium chromate, and dinitrophenol; chromated zinc chloride (CZC) – mixture of zinc chloride and sodium chromate; noncombustible fire retardant (Non-Com) – mixture of ammonium sulfate, ammonium phosphate, boric acid, borax, and dicyandiamide.

Information recording periods of use of these chemicals is not complete. The most recent wood treatment process used only 60–40 creosote. The wood was treated in pressure-vacuum cylinders powered by steam produced by a woodfired boiler. After treatment, the preserved wood was moved on to drip tracks to air dry. A drain system was in place to collect run-off from the drip track area. Besides the run-off waste, production wastes were also generated. Koppers treated the run-off and production wastes at the facility in an oil–water separator for reclamation of the oil. In June 1986, Koppers entered into an Administrative Order of Consent (AOC) with the US EPA and IEPA to perform corrective actions and other response measures at the site. Before 1988, the Koppers facility treated wastewater by collecting the effluent from the oil–water separators in a wastewater lagoon/spray irrigation field system. In November 1988, the city of Carbondale began accepting wastewater from Koppers. When Koppers abandoned the lagoon system, they generated more wastewater than they could transport and store, so they evaporated wastewater into the atmosphere by heating it in open-topped tanks. When Koppers was evaporating the water, the surrounding community complained about a strong, creosote-like odor originating from the facility. In July 1991, Koppers ceased operations at their Carbondale facility; the company dismantled and removed most of the equipment and buildings. Storage

72

Handbook of Pollution Prevention and Cleaner Production

tanks, the office building, and the wastewater treatment plant are all that remain at the site. Limited soil excavation around the work tanks and treatment cylinders was conducted at the time of dismantling; however, most of the visibly contaminated soil remains on the site. To control the shallow contaminated groundwater discharging into Glade Creek, Koppers installed a grout blanket in the bed of the creek. The grout blanket is about 700 feet long and 30 feet wide, extending from bank to bank. The grout blanket collects and conveys the groundwater that is visibly contaminated with creosote to a collection manhole where the material is periodically collected. The collected material is then treated on the site in the activated sludge wastewater treatment plant. Carbondale is in the southeastern portion of Jackson County, IL. The 1990 US Census reported the population of Carbondale at approximately 32,000 people. This number includes Southern Illinois University (SIU) students who reside within the city limits. The SIU campus is in the southern portion of Carbondale, 2 miles southwest of the Koppers site. The enrollment at SIU is approximately 24,000. The population within a 4-mile radius of the site is approximately 38,000 people. The nearest populated area is a residential neighborhood immediately south of the western end of the facility. This lower-income neighborhood has a population of about 1600 comprised predominantly of African Americans. According to the 1990 US Census, the average age of this population is 28 years. A few scattered homes are in the rural area immediately north of the site. Most of those dwellings are along Reed Station Road. Cedar Lake, which is about 8 miles south of the Koppers site, supplies the drinking water for Carbondale and the surrounding area. Surface water leaving the site has no connection to Cedar Lake. Most of the dwellings in the rural area north and northeast of Koppers are connected to the Lakeside Water District, which also receives water from the Cedar Lake supply system. Prior to 1992, about 40 homes in that area had private wells. Four private wells were within 1 mile north of the site. Three of the wells were at homes and the fourth well, at a barn, is used for watering livestock. In September 1992, public water was provided to the area. Glade Creek flows through the western portion of the site, around the northern edge, and then past the eastern end of the site. Glade Creek merges with Piles Fork Creek and then flows into Crab Orchard Creek about 1 mile downstream of the site. Surface water draining from the site flows into Glade Creek and Piles Fork Creek. Site-impacted shallow groundwater also discharges into Glade Creek. Both Glade Creek and Piles Fork Creek typically have low flow rates and become intermittent during dry periods, which makes them generally unattractive for recreational use such as swimming or fishing. Neither of the creeks is used as drinking water sources; however, in some areas, the water is available to livestock. Piles Fork Creek is used as the receiving stream for treated waste from the Carbondale sewage treatment plant. Crab Orchard Creek is also not a drinking water source for humans,

Pollution and pollution controls

73

but it may be used for recreational purposes such as wading, swimming, and sport fishing. Crab Orchard Creek ultimately flows into the Big Muddy River. Before 1993, the community of Royalton used the Big Muddy River as its drinking water supply, but the Royalton water treatment plant was about 9 miles upstream of the Crab Orchard Creek confluence. In 1993, Royalton connected to the Rend Lake Water District. The Big Muddy River is not used as a public water supply downstream of this confluence. Recreational use of the Big Muddy River includes boating, swimming, and sport and commercial fishing.

3.5.2

Hart Creosoting Co., Jasper, Jasper County, TX (http://www.epa.gov/earth1r6/6sf/pdffiles/0601975.pdf)

The site is in the Remedial Action phase of the Superfund process. The EPA signed the Preliminary Close-Out Report on 12 September 2008, documenting the construction completion at the site. The EPA and State of Texas completed the Final Inspection at the site on 10 September 2008. The EPA initiated site construction on 17 December 2007. The EPA started the remedial action at the site on 20 September 2007. It approved the final remedial design for the site on 20 September 2007. The EPA conducted a removal action in 1995 to remove existing tanks, structures and equipment, remove liquid waste for off-site disposal, drain the on-site impoundments, stabilize the remaining sludge, and consolidate the sludge and contaminated soil into an on-site waste cell. The EPA conducted a Remedial Investigation/Feasibility Study (RI/FS) and baseline risk assessment for the site in 2004 and conducted a Supplemental Remedial Investigation (SRI) in 2006. The RI and FS Reports were finalized in September 2006. The RI was conducted to further characterize the nature and extent of contamination originally documented by the earlier investigations and to provide data to support the completion of human health and ecological risk assessments. The FS report was completed to evaluate technologies and remedial alternatives for the purpose of selecting a final remedial alternative to address the risks presented in the final RI report. The EPA held a public meeting on 15 August 2006, at the City of Jasper First National Bank in Jasper, to present the proposed plan, to answer questions on the remedial alternatives, and to present the EPA’s preferred alternative for addressing cleanup of the site. The RI/FS reports and Proposed Plan for the site were made available to the public on 26 July 2006. The documents are in the Administrative Record file and the information repository is maintained at the EPA Docket Room in Region 6, at the TCEQ offices in Austin, TX, and at the Jasper City Library. The notice of the availability of these documents was published in the Jasper Newsboy on 26 July 2006. A record of decision was signed on 21 September 2006.

74

Handbook of Pollution Prevention and Cleaner Production

To date, the EPA has spent approximately $2.6 million for removal action and design work at this site. The EPA’s actions taken to date have considerably lessened the potential for undue human health or environmental exposure.

3.5.3

Higgins Wood Preserving Co., Lufkin, Angelina County, TX (http://www.tceq.state.tx.us/remediation/superfund/state/ higgins.html)

The Higgins Wood Preserving site in Lufkin is bounded on the west side by N. Timberland Drive (US 59), on the east side by Warren Street, and on the north by Paul Avenue. From as early as 1937, and until 1973, several wood-creosoting activities were conducted on this site. All of the operations used creosote, and reportedly at least one used PCP, to treat wood products. The land was sold as a shopping center site in 1976, and the former holding ponds were filled in and graded over. As much as 125,000 gallons of creosote residue were left on the bottom. In 1980, creosote leachate was detected in the drainage ditches on the site. The following are Superfund actions taken to date: 



 

         

25 September 1990 – a legal notice was published in the Texas Register (15 TexReg 5623-5624) describing the site, proposing the site to the state Superfund registry, and announcing that a public meeting to receive citizen comments would be held at the Lufkin City Council Chambers on 24 October 1990. October 1992 – a Texas Natural Resource Conservation Commission agreed order was signed by all potentially responsible parties to pay for a remedial investigation, and establishing rules, responsibilities and enforcement options for responsible party cleanup under monitoring supervision of the state. 12 November 1992 – remedial investigation under way. 1 September 1993 – effective date of the creation of the Texas Natural Resource Conservation Commission (TNRCC) from the joining of the Texas Water Commission and the Texas Air Control Board and a portion of the Texas Department of Health. 7 September 1994 – Phase I remedial investigation under way. 17 April 1996 – Phase I report received and reviewed, Phase II remedial investigation under way. 10 October 1996 – Phase II report received and reviewed, Phase III remedial investigation under way. 19 March 1999 – feasibility study under way. 19 March 1999 – human health risk assessment completed. 26 May 1999 – a work plan was completed for assessing the practicability of remediating the groundwater. June–December 1999 – access agreements were negotiated for investigation activities on private properties. 18 February 2000 – field work completed for technical impracticability demonstration. 30 January 2001 – the TNRCC approved the final feasibility study report. 28 March 2001 – notices were sent to PRPs (Potentially Responsible Party) informing them that the RI/FS administrative order had been completed and they had

Pollution and pollution controls



  







75

30 days to advise the TNRCC of their intent to either enter the Voluntary Cleanup Program (VCP) or proceed under Superfund. 16 April 2001 – the Higgins site committee sent a letter declaring intent to enter the Voluntary Cleanup Program. As a part of entering the VCP, the past oversight costs must be paid by the PRPs. 29 January 2002 – the TNRCC Voluntary Cleanup Program completed the review of the application and assigned a project number (VCP 1397). 30 January 2002 – an updated copy of the community relations plan was prepared for the Higgins Wood Preserving site. 22 March 2002 – a legal notice was published in the Texas Register (27 TexReg 2323) proposing to delete the site from the state Superfund registry in accordance with 30 TAC x335.344(c) and inviting comment prior to, or at, a public meeting to be held on 25 April 2002 at the TNRCC offices, 12100 Park 35 Circle Austin, TX 78753, 512-239-2920, Building D, Room 264. Remediation of the site will be monitored by the Voluntary Cleanup Program. 25 April 2002 – a public meeting was held at the TNRCC offices to receive comments on the proposal to delete Higgins Wood Preserving from the state Superfund registry. No comments were received challenging the deletion in accordance with 30 TAC x335.344(c). Remediation of the site will be monitored by the Voluntary Cleanup Program. 7 June 2002 – a legal notice was published in the Texas Register (27 TexReg 50145015) officially deleting Higgins Wood Preserving from the state Superfund registry in accordance with 30 TAC 335.344(b). Favorable comments regarding the proposed deletion were received at the public meeting. No further remedial action was planned. 1 September 2002 – effective date of the name change from Texas Natural Resource Conservation Commission (TNRCC) to Texas Commission on Environmental Quality (TCEQ).

3.5.4

The American Creosote Works site, Pensacola, FL (US EPA, 1989a)

The 18-acre American Creosote Works (Pensacola plant) site is located in a dense, moderately commercial and residential area of Pensacola, FL. A woodpreserving facility operated at this site from 1902 to 1981. During this time, process wastewater containing PCP was discharged into unlined, on-site surface impoundment ponds. Before 1970, these impoundment ponds were allowed to overflow through a spillway into neighboring bays. After 1970, wastewater was discharged to designated on-site spillage areas. Additional discharges occurred during periods of heavy rainfall when the ponds overflowed. In March 1980, the city found considerable quantities of oily, asphaltic, creosote material in the groundwater near the site. Because of the threat posed to human health and the environment, the EPA and the state performed an emergency cleanup in 1983. This included dewatering the ponds, treating the water, and discharging treated water into the city sewer system. The sludge in the ponds was then solidified and capped. The EPA signed a record of decision (ROD) in 1985 requiring all on-site and off-site contaminated solids, sludge, and sediment to be placed in an on-site RCRA-permitted landfill. A second ROD, signed in 1989, addresses remediation

76

Handbook of Pollution Prevention and Cleaner Production

of contaminated surface soil. A future ROD will address treatment of contaminated subsurface soil, sludge, and groundwater. The primary contaminants of concern affecting the surface soil are organics, including dioxins, carcinogenic PAHs, and PCP. The selected remedial action for this site includes: 

   

excavating and treating 23,000 cubic yards of PAH-contaminated soil using solidphase bioremediation at an on-site land treatment area, with monitoring of dissolved oxygen, pH, nutrients, and soil moisture content; disposal of treated soil on site in the excavated areas or by spreading the soil over the entire site; spraying collected drain water over the treatment area to moisten soil; repairing fences around the site, monitoring the site cap; implementing groundwater use restrictions.

The estimated cost for this approach is $2,275,000.

3.5.5

The Koppers site, Oroville, CA (US EPA, 1989b)

The Koppers site is a 200-acre operating wood-treating plant in Butte County, CA. Nearby land use is mixed agricultural, residential, commercial, and industrial. Although there is a history of wood-treating operations at the site, they were greatly expanded in 1955 when Koppers Company Inc. became the owner and operator. PCP, creosote, and CCA solutions are among the chemicals that have been used at this site. Wastewater discharge and other site activities have resulted in contamination of unlined ponds, soil, and debris. PCP was detected in on-site groundwater in 1971 and in residential wells in 1972. Pursuant to a state order, Koppers conducted cleanup activities from 1973 to 1974, including groundwater pumping and discharge to spray fields and off-site disposal of contaminated debris, and process changes, including construction of a wastewater treatment plant. In 1986, Koppers provided nearby residents an alternate water supply for domestic uses. Following a 1987 explosion and fire at a PCP wood-treatment process facility, the EPA issued a removal order requiring cleanup of fire debris and removal and stabilization of surface soil. The present ROD addresses the remaining contamination in on-site soil and groundwater affected. The primary contaminants of concern are PAHs, PCP, dioxins and furans, and metals including arsenic and chromium. The selected soil remedy includes:  



on-site biodegradation of 110,000 cubic yards of PCP-contaminated soil; excavation and soil washing of 200,000 cubic yards of soil contaminated with woodtreating wastes with disposal of treated soil on site and treatment of residual contamination in the washing fluid in an on-site treatment facility; installation of a low-permeability cap over the wood-treating process area (an interim remedy) and down gradient extraction wells, and excavation and chemical fixation of 4000 cubic yards of soil contaminated with metals, followed by on-site disposal.

Pollution and pollution controls

77

The groundwater remedy includes pumping and treatment of approximately 22,000,000 cubic yards of groundwater using activated carbon, reinjection of treated waste to the groundwater, and formalization of the provision of an existing alternate water supply and extension, if needed, of the water supply during implementation of the remedy. According to the ROD the estimated cost for this cleanup strategy was $77,700,000. The EPA has had some difficulties implementing bioremediation at the Koppers site. It found that the soil excavated for a bioremediation treatability study was contaminated with more dioxin than anticipated. This caused the cancellation of the treatability study and a switch to a removal action, placing soil in an RCRA-approved landfill. The soil-washing pilot test showed that soil washing was not capable of meeting cleanup standards. Bioremediation effectively destroyed PCP but was not effective in reducing dioxins. The owner is re-evaluating soil remedies for the remainder of this site.

3.5.6

The Koppers site, Morrisville, NC (US EPA, 1992)

The 52-acre Koppers Morrisville site is a wood-laminating facility in Morrisville, Wake County, NC. Surrounding land use is a mixture of commercial, light industrial, and rural residential. The site has been used by lumber companies since 1896. In 1962, Koppers began treating wood at the site using PCP and isopropyl ether injected into wood. Process wastes were put into unlined lagoons. Koppers discontinued wood treatment in 1975, but past woodtreatment processes and associated disposal activities have left the site contaminated with PCP, dioxins, and isopropyl ether, affecting the soil, groundwater, and surface water. In 1989, in response to state studies of water contamination from the site, nearby residents began using public water lines instead of wells to obtain drinking water. In 1990, the EPA required extensive studies of the soil, groundwater, drainage pathways and ponds, and also determined that additional studies were needed to further assess contamination of the surface soil in the lagoon and wood-treatment process areas. In 1992, the EPA completed an ROD for the site that specified incineration as the primary remedy and basecatalyzed decomposition (BCD) as the ‘‘contingency remedy’’ whose use would be dependent upon the results of a treatability study. One driving force for providing for an alternative to incineration was the strong interest of the community. The primary strategy was off-site incineration of soil involving:   

excavation of contaminated soils from lagoon and process areas and transportation to an off-site permitted incineration facility; extraction of contaminated groundwater from within the plume via extraction well(s) and piping it to an on-site carbon adsorption treatment unit; use of institutional controls including fencing of the pond, lagoon, and woodtreatment process areas.

78

Handbook of Pollution Prevention and Cleaner Production

Base-catalyzed dehalogenation was selected as a contingency cleanup strategy. According to the 1992 ROD, BCD could substitute for off-site incineration if it proved itself in treatability studies. BCD would involve the excavation of contaminated soils from the lagoon and process areas, and transportation to an on-site BCD treatment system. According to the ROD, the estimated cost for the selected cleanup strategy was $11,500,000. The treatability study with BCD was completed in August 1993. The results showed that BCD was effective in treating soil contaminated with both PCP and dioxins. However, it may be premature to consider BCD a general technology for wood-treatment site cleanup. The size of this demonstration was very small compared to other wood-treatment sites. The BCD demonstration involved only 700 cubic yards of soil; the amounts of soil requiring treatment at some of the largest contaminated wood-treatment sites are as much as 100 times larger. Another concern raised by one EPA wood-treatment site manager is that the results from this BCD trial seem to show significant stack emissions, presumably from the thermal desorption stage, that are equal to or greater than those that would be seen if incineration had been used instead of BCD. For BCD to be considered successful at this site, it had to achieve 7 parts per billion (ppb) or lower dioxin levels in the treated soil. However, the soil levels were fairly low to begin with and dioxin soil concentrations were probably not very important for the choice of BCD as a soil cleanup technology. The neighboring community was brought into the treatability study process. More than 100 citizens were invited to observe the results of the BCD treatability study. According to one EPA official involved with the study, the citizen involvement was very helpful in the overall process of developing the alternative. A new ROD has been approved that specifies BCD as the primary means of treating contaminated soil. Koppers, as the principally responsible site owner, is in the process of awarding a contract to build a full-scale on-site BCD treatment facility.

3.5.7

The Arkwood Inc. site, Omaha, AR (US EPA, 1990)

The 15-acre Arkwood site is a former wood-treatment facility in Boone County, AR. Land use in the vicinity of the site is primarily agricultural and light industrial. Approximately 200 residences are located within 1 mile of the site, and 35 domestic water supply wells are within 1.5 miles of the site. Groundwater on or near the site is highly susceptible to contamination as a result of underground cavities, enlarged fractures, and conduits that hinder monitoring and pumping. From 1962 to 1973, Arkwood operated a PCP and creosote wood-treatment facility at the site. In 1986, the site owner dismantled the plant. State investigations conducted during the 1980s documented PCP and creosote contamination in surface water, soil, debris, and buildings throughout the site. Contaminated surface features at the site include the wood-treatment

Pollution and pollution controls

79

facility, a sinkhole area contaminated with oily waste, a ditch area, a wood storage area, and an ash pile. In 1987, the EPA ordered the site owner to perform an immediate removal action that included implementing site access restrictions, such as fencing and sign postings. The present ROD addresses remediation of all affected media and provides the final remedy for the site. The primary contaminants affecting the soil, sludge, debris, and groundwater are organics including PCP, PAHs, and dioxins. The selected remedial action for this site includes:       

excavating approximately 21,000 cubic yards of contaminated soil and sludge followed by soil washing; on-site incineration of approximately 7000 cubic yards of materials that exceed cleanup levels; incineration of any free oil wood-treating material; using washed and decontaminated materials and any residual ash for backfilling; covering the site with a soil cap and planting revegetation; site access restrictions including fencing; monitoring of drinking and groundwater and connecting affected residences to municipal water lines.

According to the ROD, the cost of this approach would be $10,300,000.

3.5.8

The United Creosoting site, Conroe, TX (US EPA, 1989c)

The 100-acre United Creosoting site in Conroe, Montgomery County, TX, is occupied by a residential subdivision, a distributing company, and a construction company. From 1946 to 1972, the United Creosoting Company operated a wood-preserving facility at the site. PCP and creosote were used in the wood-preservation process, and process wastes were stored in waste ponds. During 1980, the county used soil and waste pond backfill from the site on local roads. After residents living near the improved roadways experienced health problems, the county sampled and compared leachate composition from the affected roadways and the site. They determined that leachate from both the site and the roadways was contaminated with PCP. Roadway soil was subsequently removed and disposed of using land farm treatment. In 1983, in response to contaminated stormwater run-off from the former waste pond areas, the property owner was directed under terms of an EPA Administrative Order to regrade contaminated soil, divert surface water drainage away from the residential portion of the site, and cap the contaminated soil. The present ROD specifies a final remedy for contaminated soil at the site and complements a 1986 ROD that determined that no action was necessary to remediate shallow groundwater. The primary contaminants of concern affecting the soil are organics including PAHs, PCP, and dioxins.

80

Handbook of Pollution Prevention and Cleaner Production

The selected remedial action for this site includes: 

 

excavation and on-site treatment of 94,000 cubic yards of soil containing contaminants that exceed target action levels using critical fluid extraction with liquid propane; off-site incineration of residues containing the concentrated contaminants produced by this technology; recycling or discharge of wastewater generated during the treatment process, spreading treated soil on the commercial portion of the site, and backfilling residential areas with clean fill.

According to the ROD, the estimated cost for this remedial action is $22,000,000. However, based on a signed contract for a major portion of the remedial activities and estimates for the remainder of the work, the expected cost of this cleanup is now expected to exceed $34,000,000.

References Bendavid-Val, A., Cheremisinoff, N.P., 2001. Green Profits: A Manager’s Handbook to ISO 14001 and Pollution Prevention. Butterworth-Heinemann, Oxford. Cheremisinoff, N.P., 2001. Pollution Prevention Practice Handbook. Marcel Dekker, New York. Fowler, L., Trump, W.N., Vogler, C.E., 1968. Vapor Pressure of Naphthalene: New Measurements between 40 deg. and 180 deg. Journal of Chemical Engineering Data 13 (2), 209–210. Goldfarb, J.L., Suuberg, E.M., 2008. Vapor Pressures and Enthalpies of Sublimation of Ten Polycyclic Aromatic Hydrocarbons Determined via the Knudsen Effusion Method. Journal of Chemical Engineering Data 53, 670–676. Mackay, B., Shiu, W.-Y., Ma, K.-C., 1999. Physical–Chemical Properties and Environmental Fate and degradation Handbook. Chapman & Hall, Boca Raton, FL. McDermott, H.J., 2006. Air Monitoring for Toxic Exposures. John Wiley, New Jersey. Moore, W.J., 1962. Physical Chemistry, third ed. Prentice-Hall, Englewood Cliffs, NJ, pp. 103–107. Mueller, J.G., Middaugh, D.P., Lantz, S.E., Chapman, P.J., 1991. Biodegradation of Creosote and Pentachlorophenol in Contaminated Groundwater: Chemical and Biological Assessment. Applied Environmental Microbiology 57 (5), 1277–1285. Rietz, R.C., 1957. Importance of Dry Lumber. Report No. 1779. US Forest Products Laboratory, Madison, WI. Thomson, N.R., Fraser, M.J., Lamarche, C., Barker, J.F., Forsey, S.P., 2008. Rebound of a Coal Tar Creosote Plume Following Partial Zone Treatment with Permanganate. Journal of Contaminant Hydrology 102 (1–2), 154–171. US Environmental Protection Agency (EPA), 1989a. Region 4, ‘‘Record of Decision: American Creosote Works Inc. Site.’’ EPA, Atlanta, GA, 5 January. US Environmental Protection Agency (EPA), 1989b. Region 9, ‘‘Record of Decision: Koppers Co. Inc. (Oroville Plant) Site.’’ EPA, San Francisco, CA, September. US Environmental Protection Agency, 1989c. Region 6, ‘‘Record of Decision: United Creosoting Co. Site.’’ EPA, Dallas, TX, September.

Pollution and pollution controls

81

US Environmental Protection Agency (EPA), 1990. Region 6, ‘‘Record of Decision: Arkwood, Inc. Site.’’ EPA, Dallas, TX, September. US Environmental Protection Agency (EPA), 1992. Region 4, ‘‘Record of Decision: Koppers Site (Morrisville Plant).’’ EPA, Atlanta, GA, December. US Environmental Protection Agency (EPA), 2001. Drip Pads, 40 CFR Parts 264/265, Subpart W. Updated October 2001. EPA530-K-02–008I. US Forest Service, 1963. Study of Temperature in Wood Parts of Houses Throughout the United States. US Forest Research Note FPL-012, August.

4 Air pollution from wood treatment 4.1 Introduction This chapter attempts to bring some rationalization to the methods for estimating air emissions from wood-treating plants. Facilities do not measure their air emissions. They apply calculation procedures based on methodology and formulae provided in the US Environmental Protection Agency (EPA)’s AP-42 publication. There are several problems with this approach, including the following: 1. Emission factors reported in AP-42 for the industry sector are unreliable and incomplete. For example, there are no emission factors reported for wood-treating plants that use pentachlorophenol, and only a few polycyclic aromatic hydrocarbons (PAHs) are considered. 2. AP-42 emission factors do not account for temperature excursions that are known to increase volatile and semi-volatile chemical vaporization. 3. The methodology defined in AP-42 for estimating fugitive air emissions from the surfaces of freshly treated wood does not accurately reflect stacking configurations, which can vary among wood treaters. Stacking configuration has a first-order effect on air emissions and improper estimation of the effective surface area of exposure can lead to conservatively low predictions of air emissions. 4. Because facilities are only required to report calculated yearly emissions under the Toxics Release Inventory program, seasonal effects are never considered by wood treaters. When treated wood is stored in open areas and exposed to direct sunlight, surface temperatures during hot summer months can be many degrees higher than the surrounding ambient air, and as such may result in excessive emissions at times, thus placing workers and neighboring communities at risk from acute exposures to poor air quality. 5. AP-42 does not provide any emission factors for volatile organic compounds (VOCs) in wood-treating plants. VOCs are largely ignored despite the fact that the material safety sheets of treating chemical suppliers disclose that benzene and other VOCs are present in their products.

The industry and the AWPI (American Wood Preservers Institute) have argued since the 1970s that the chemicals used in the preservation of wood are not carcinogens despite overwhelming scientific and governmental supported investigations to the contrary. Virtually all of the emission factor data provided in AP-42 are from industry-reported studies or studies promoted by the AWPI. The industry has not been transparent in its emissions reporting and has established and promoted conservative estimation methods for air emissions because it is to its advantage.

Handbook of Pollution Prevention and Cleaner Production Vol. 2 Copyright Ó 2010 by Elsevier Inc. All rights reserved.

84

Handbook of Pollution Prevention and Cleaner Production

4.2 Emission sources The following is a list of common emission sources at wood-treating plants: 1. 2. 3. 4. 5. 6. 7. 8. 9.

vapors from the surfaces of freshly treated wood; vapors emitted during the treating cycle; kiln emissions; losses and leaks from valves and piping aperture; tank breathing and working losses; vapors from surface ponds and drainage ditches; dust emissions from on-site heavy machinery traffic; boiler emissions; emissions from fuel-burning operations such as internal combustion engines, compressors, heaters; 10. conical or tepee burner emissions; 11. land farming and other on-site waste management activities that can result in fugitive air emissions.

Not all of these emission sources may be found at every wood-treating plant. In order to prepare an accurate estimate of emissions, the on-site activities need to be carefully considered in preparing an emissions inventory. The emission sources listed fall into two general categories: fugitive and point sources. A point source is an emission that is fixed and/or uniquely identifiable, such as a stack or vent. Fugitive emissions are those emissions entering into the atmosphere that are not released through a stack, vent, duct, pipes, storage tank, or other confined air stream. These emissions include area emissions and equipment leaks. For creosote coal tars, the emissions of concern are PAHs from all of the sources identified. For pentachlorophenol (PCP), the emissions of concern are dioxins and furans from all of the sources identified. The constituents of both creosote and PCP themselves are semi-volatile chemicals that vaporize from surfaces that are exposed to the atmosphere. When spilled or dripped on to soil, contaminated airborne dust particles become suspended in the air when heavy machinery travels over these areas. Chromated copper arsenate (CCA) does not vaporize. It is a salt that is prepared in a solution of water and when applied to wood, the chemical remains with the treated wood. Spills and drippage on to land areas where heavy machinery travels are a source of fugitive dust emissions that contain arsenic and chromium from the residues. Low levels of fugitive emissions will also occur from the treating process and when mixing is performed in open systems. While the contributions of each of the sources to any one facility’s overall emissions may be modest to small, cumulatively they may contribute to significant mass emissions. Additionally, emissions can worsen during different times of the year depending on environmental conditions. Not all of the possible emission sources are considered in this chapter. Focus is placed on those sources that generally are under-reported because of a lack of clarity in calculation procedures provided in the published literature.

Air pollution from wood treatment

85

The reader may wish to examine the discussion on volatilization in Section 3.4. Empirical correlations provided for vapor pressures of PAHs are referred to and used in the foregoing discussions.

4.3 Emission factors 4.3.1

Emission factor definition and reliability of data

The US Environmental Protection Agency (EPA) publishes Compilation of Air Pollutant Emission Factors, best known as AP-42. The first official version was published in 1972. Supplements to AP-42 have been routinely published to add new emission source categories and to update existing emission factors. According to the EPA: An emission factor is a representative value that attempts to relate the quantity of a pollutant released to the atmosphere with an activity associated with the release of that pollutant. Emission factors usually are expressed as the weight of pollutant divided by the unit weight, volume, distance, or duration of the activity that emits the pollutant.

The EPA further reports that the emission factors presented in AP-42 may be appropriate to use in a number of situations, including making source-specific emission estimates for area-wide inventories for dispersion modeling, developing control strategies, screening sources for compliance purposes, establishing operating permit fees, and making permit applicability determinations. For the wood-preserving industry AP-42 Section 10.8, titled ‘‘Wood Preserving’’, is an essential reference, especially when emissions are not measured by a facility but are estimated based on calculation. Section 10.8 consists of five sections, which cover: (1) an introduction to the publication; (2) a description of the wood-preserving industry, including a characterization of the industry, a description of the different process operations, a characterization of emission sources and pollutants emitted, and a description of the technologies used to control emissions resulting from these sources; (3) a review of emission data collection (and emission measurement) procedures; (4) information on how the AP-42 section was developed, including a review of specific data sets and a description of how candidate emission factors were developed; and (5) recommended emissions calculation methods, which constitute the core of AP-42 Section 10.8, ‘‘Wood Preserving’’. It is reasonable to expect that any methodology and procedure used for the purpose of quantifying air emissions should be reproducible and provide representative emissions. It is, however, impossible to provide precise air emissions data in any industry sector based on the current limitations of available knowledge. The reason for this statement is that the favored method among all US industrial facilities is to estimate emissions by calculation methods that rely

86

Handbook of Pollution Prevention and Cleaner Production

solely on emission factors that are arithmetic averages of emissions reported from different plants. While technologies within any one industry sector are the same, operational practices can vary widely, thereby resulting in emission factors that significantly vary from one facility to another. A good example is the refining industry. The EPA has reported in industry sector books that no two refineries are the same. Since no two refineries are the same, then the average emission factors reported in the refining sector AP-42 supplement cannot be viewed as precise representations of any one facility. The same may be said for wood-treating facilities, with an even greater degree of concern for the accuracy of emission factors for the reasons explained below. The basic argument that has been adopted in support of AP-42 methodology for emissions quantification is that application of recommended emission factors on average is believed to represent the mass emissions from any one facility. And since neither the American Wood Preservers’ Association (AWPA) nor any major wood-treating company has developed alternative methods for more accurately quantifying air emissions, we are presently stuck with the information in AP-42. In developing the collection of emission factors, the EPA relied on a variety of sources within the Office of Air Quality Planning and Standards (OAQPS) and from outside organizations including those generated by the AWPA, the Railway Tie Association, and specific facilities within the industry, which provided reviews and comments of draft versions of Section 10.8. To screen out unusable test reports, documents, and information from which emission factors could not be developed, the EPA applied the following criteria: 1. Emission data must be from a primary reference: a. Source testing must be from a referenced study that does not reiterate information from previous studies. b. The document must constitute the original source of test data. For example, a technical paper was not included if the original study was contained in the previous document. If the exact source of the data could not be determined, the document was eliminated. 2. The referenced study should contain test results based on more than one test run. If results from only one run are presented, the emission factors must be down rated. 3. The report must contain sufficient data to evaluate the testing procedures and source operating conditions (e.g. one-page reports were generally rejected).

A final set of reference materials was compiled after a review of the pertinent reports, documents, and information according to these criteria. The following was applied by the EPA as the basis for rejecting some data as outliers: 1. test series averages reported in units that cannot be converted to the selected reporting units; 2. test series representing incompatible test methods (i.e. comparison of EPA Method 5 front half with EPA Method 5 front and back halves); 3. test series of controlled emissions for which the control device is not specified; 4. test series in which the source process is not clearly identified and described;

Air pollution from wood treatment

87

5. test series in which it is not clear whether the emissions were measured before or after the control device.

Any test data sets that were not excluded were assigned a quality rating. The rating system used was as follows: 









A – Excellent: developed only from A- and B-rated test data taken from many randomly chosen facilities in the industry population. The source category is specific enough so that variability within the source category population may be minimized. B – Above average: developed only from A- and B-rated test data from a reasonable number of facilities. Although no specific bias is evident, it is not clear if the facilities tested represent a random sample of the industries. The source category is specific enough so that variability within the source category population may be minimized. C – Average: developed only from A-, B-, and/or C-rated test data from a reasonable number of facilities. Although no specific bias is evident, it is not clear if the facilities tested represent a random sample of the industry. In addition, the source category is specific enough so that variability within the source category population may be minimized. D – Below average: the emission factor was developed only from A-, B-, and/or Crated test data from a small number of facilities, and there is reason to suspect that these facilities do not represent a random sample of the industry. There also may be evidence of variability within the source category population. Limitations on the use of the emission factor are noted in the emission factor table. E – Poor: the emission factor was developed from C- and D-rated test data, and there is reason to suspect that the facilities tested do not represent a random sample of the industry. There also may be evidence of variability within the source category population. Limitations on the use of these factors are footnoted.

AP-42 Section 10.8 notes that the use of these criteria is somewhat subjective and depends to an extent upon the individual reviewer. For the emissions factors reported for fugitive air emissions from treated wood, the majority of the data have been rated ‘‘C–D’’ by the EPA. Because of the uncertainties that the EPA reports for the emission factors published in Section 10.8, we have consulted the scientific literature for additional sources of emission factors.

4.3.2

Fugitive emissions from treated wood

AP-42 Section 10.8 provides emission factors for calculating these emissions, but only for some PAHs. There are limitations with the emission factors reported in AP-42: 1. AP-42 does not provide emission factors for VOCs. Creosote contains benzene and other VOCs. The general literature shows that benzene is found in trace amounts in creosote coal tars. Wood treaters also use diesel and fuel oil as an extender for the PCP and creosote coal-tar mixes. These products contain

88

Handbook of Pollution Prevention and Cleaner Production

benzene, xylene, toluene, and ethylbenzene, as does coal-tar creosote. Just because the wood-preserving industry has not provided emission factors for AP-42 for these constituents it does not mean they are not emitted from a woodpreserving plant. 2. The emission factors reported in AP-42 are average values from different woodtreating plants. These include tie-, pole-, and lumber-treating plants. AP-42 reported emission factors do not distinguish the sources of emission factors provided by industry to the EPA nor does AP-42 report the statistical variances of the data. It only states that overall the factors are of poor quality. Some emission factor data reported are based on single measurements. This means that emissions calculated using the formulae and emission factors in Section 10.8 are not precise, nor can a reasonable confidence limit be placed on calculated emissions. 3. AP-42 emission factors do not take into account the effect of temperature. The EPA notes in Section 10.8 that a correction for wood temperature is important to obtaining accurate estimates of the fugitive emissions; however, it only provides a temperature correction for a single PAH, naphthalene.

Gallego et al. (2008) have reported on the emissions of VOCs, in particular aromatic hydrocarbons containing one benzene ring and furans, and PAHs from wood treated with creosote. The VOCs and PAHs were identified and quantified in both the gas and particulate phases. As noted in Chapter 3 PAHs are semi-volatile compounds, and as such they enter the atmosphere both as vapors and as particulate matter. The main components of the vapors identified as released from the creosote-treated wood studied by Gallego and co-workers were naphthalene, toluene, m- and p-xylene, ethylbenzene, o-xylene, isopropylbenzene, benzene, and 2-methylnaphthalene. VOC emission concentrations ranged from 35 mg/m3 of air on the day of treatment to 5 mg/m3 8 days later. PAH emission concentrations ranged from 28 mg/m3 of air on the day of treatment to 4 mg/m3 8 days later. The air concentrations of PAHs in particulate matter were composed predominantly of benzo[b,j]fluoranthene, benzo[a]anthracene, chrysene, fluoranthene, benzo[e]pyrene, and 1-methylnaphthalene. The emission concentrations of particulate PAHs varied between 0.2 and 43.5 ng/m3. The investigators reported calculated emission factors of VOCs and PAHs. The Gallego investigation was performed on creosote-treated poles. Gallego et al. report that the emissions up to day t can be determined using the following integrated equation:    E C1 ¼ (4.1) 1  eC2 t g=m2 C2 A where E ¼ mass emitted in grams, A ¼ emission area of the poles in square meters, t ¼ time in days, and C1 and C2 are emission constants. Equation (4.1) is referenced to a temperature of 80 F. The values of the emission constants C1 and C2 are reported in Table 4.1. Gallego et al. also provide temperature corrections for the emissions parameters. The investigators using EPA methodology derived the following

Air pollution from wood treatment

89

Table 4.1 Emission constants reported by Gallego et al. (2008) Creosote compound

C1 (g/m2/day)

C2 (dayL1)

Benzene Toluene Ethylbenzene m- and p-Xylene o-Xylene Isopropylbenzene Benzonitrile Phenol Naphthalene 2-Methylnaphthalene 1-Methylnaphthalene Biphenyl 1-Ethylnaphthalene 2,6-Dimethylnaphthalene 1,2-Dimethylnaphthalene Benzofuran Dibenzofuran Benzo[b]thyophene Acenaphthylene Acenaphthene Fluorene Phenanthrene Anthracene Fluoranthene Pyrene Benzo[a]anthracene Chrysene Benzo[b,j]fluoranthene Benzo[k]fluoranthene Benzo[a]pyrene Indeno[1,2,3-c,d]pyrene Benzo[g,h,i]perylene Dibenzo[a,h]anthracene Indene 2-Methylnaphthalene 1-Methylnaphthalene

0.016 0.049 0.054 0.396 0.027 0.032 0.011 0.032 0.572 0.019 0.002 0.016 0.001 0.003 0.002 0.003 n.d. 0.001 2.40E04 0.029 0.003 n.d. 3.70E05 n.d. 2.50E05 n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 0.040 0.019

0.202 0.158 0.189 0.466 0.194 0.185 0.111 0.067 0.247 0.054 0.011 0.054 0.095 0.144 0.111 0.303 n.d. 0.301 0.055 0.017 0.032 n.d. 0.239 n.d. 0.035 n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. n.d. 0.034 0.060

expression, which accounts for both the temperature of the treated wood and the time from which it is removed from the treating cylinders:    E ðC1 =C2 Þ  ¼ (4.2) 1  eC2 t e8531ð1=a1=540Þ A 0:643 where a ¼ T þ 460 and T ¼ temperature in degrees fahrenheit ( F). Equation (4.2) allows calculation of creosote emissivity at temperature

90

Handbook of Pollution Prevention and Cleaner Production

T ( F). The formula gives the accumulated mass of PAHs emitted until time t (days). No emission constants were reported by Gallego et al. for the following PAHs: dibenzofuran, phenanthrene, fluoranthene, benzo[a]anthracene, chrysene, benzo[b,j]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3c,d]pyrene, benzo[g,h,i]perylene, dibenzo[a,h]anthracene, and indene. These compounds were not detected in the measurements made by Gallego et al. This does not mean that such chemicals are not emitted, only that the data source obtained in the study had nondetects. AP-42 acknowledges that these chemicals are emitted from freshly treated wood surfaces that have been treated with creosote. Section 10.8 does provide emission factors for several PAHs all referenced to 80 F. The emission factors are provided in Table 4.2, where t is defined as earlier (time in days since removal for treating cylinder). AP-42 provides a temperature correction for naphthalene: TCFnaph ¼ e11;161ð1=a1=540Þ :

(4.3)

While it would seem that the combination of the Gallego et al. study and the emission factors reported in AP-42 provide sufficient information to precisely calculate the PAH emissions from the surfaces of freshly treated wood, there are significant differences between the two sets of published data. Table 4.3 provides a side-by-side comparison of the calculated emissions using the emission factors reported in the literature (Gallego et al.) and AP-42 for the PAHs that are reported in both publications. Table 4.3 shows that AP 42 emission factors result in higher emissions for all of the PAHs, with differences ranging between 5 and 677 times higher emissions than those calculated using the Gallego et al. published emission factors. On average, the difference between the emissions computed using AP-42 emission factors and those reported by Gallego et al. is 143 (i.e. AP-42 provides mass emissions that are 143 times greater than those calculated using the emission factors published in the literature, for the same reference temperature).

Table 4.2 AP-42 emission factors for PAHs PAH

Emission factor (lb/1000 ft2 wood treated)

Naphthalene Acenaphthylene Acenaphthene Fluorene Phenanthrene Anthracene Fluoranthene Pyrene

E E E E E E E E

¼ 6.31  5.78e0.0357t ¼ 0.0912  0.0844e0.0633t ¼ 3.04  2.82e0.0446t ¼ 1.68  1.59e0.0515t ¼ 2.19  2.13e0.0544t ¼ 0.0995  0.0891e0.0759t ¼ 0.0998  0.0957e0.0838t ¼ 0.0203  0.0195e0.0939t

Naphthalene

Acenaphthylene

Acenaphthene

Fluorene

Anthracene

Pyrene

Month

AP-42

Gall. Diff. AP-42 Gall. Diff. AP-42 Gall. Diff. AP-42 Gall. Diff. AP-42 Gall. Diff. AP-42 Gall. Diff.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Sum

1023 1182 1516 1570 2368 2705 2986 3085 1867 1804 1626 679 22,411

243 267 314 321 425 466 500 511 361 353 329 188 4278

Ave. diff.

4.2 4.4 4.8 4.9 5.6 5.8 6.0 6.0 5.2 5.1 4.9 3.6 5.0

11.6 11.6 11.6 11.6 11.6 11.6 11.6 11.6 11.6 11.6 11.6 11.6 139.3

0.2 0.2 0.3 0.3 0.4 0.4 0.4 0.5 0.3 0.3 0.3 0.2 3.8

56 51 42 41 31 28 26 25 37 37 40 74 40.8

325 325 325 325 325 325 325 325 325 325 325 325 3901

32 36 43 44 59 66 71 72 50 49 45 24 592

10.0 9.1 7.6 7.4 5.5 5.0 4.6 4.5 6.5 6.7 7.2 13.4 7.3

182 182 182 182 182 182 182 182 182 182 182 182 2189

3.0 3.3 4.0 4.1 5.5 6.1 6.5 6.7 4.6 4.5 4.2 2.3 54.7

61 55 46 45 33 30 28 27 39 40 44 81 44.1

15 15 15 15 15 15 15 15 15 15 15 15 176

0.02 0.02 0.02 0.02 0.03 0.03 0.03 0.03 0.02 0.02 0.02 0.01 0.28

916 834 708 691 522 476 444 434 615 629 675 1182 677

2.86 2.86 2.86 2.86 2.86 2.86 2.86 2.86 2.86 2.86 2.86 2.86 34.29

0.02 0.03 0.03 0.03 0.04 0.05 0.05 0.05 0.04 0.04 0.03 0.02 0.45

117 105 88 86 64 58 54 52 76 78 84 155

Air pollution from wood treatment

Table 4.3 Comparison of mass emissions calculated using different emission factors for 1 year of treated wood production from a pole plant

84.6

91

92

Handbook of Pollution Prevention and Cleaner Production

Gallego et al. relied on AP-42 methodology to calculate their published emission factors. But the investigation was limited to stacked poles. The emission factors are not based on conditions that simulate actual handling conditions at a wood-treating plant. Relying on Gallego et al.’s emission factors would result in mass emissions that may underestimate the fugitive emissions for this source term. Considering AP-42 emission factors alone would also underestimate mass emissions because no temperature correction terms are provided for PAHs other than naphthalene, and emission factors for only eight PAHs are reported. We have found no examples where wood-treating facilities actually measure air emissions that are reported under the Toxics Release Inventory (TRI) program. Mass emissions are calculated from the limited guidelines provided under AP-42, and as such only fugitive emissions for a few PAHs are reported by wood-treating facilities. Facilities do perform spot air quality monitoring through Occupational Safety and Health Administration (OSHA)-type inspections. These are generally conducted by a company industrial hygienist (IH). We examined the IH reports from several wood-treating plants and found these to be inadequate. Early reports published by the National Institute of Occupational Safety and Health (NIOSH) from the late 1970s and early to mid-1980s for limited inspections at woodtreating facilities also proved to be inconclusive. These studies were unreliable because measurements most often were for personal monitoring for coal-tar pitch volatiles (CTPVs) and grab samples did not show statistical significance. One study at the Somerville Tie Plant in Texas performed in the early 1980s showed that more than 40% of CTPVs found to exceed OSHA threshold limit values (TLVs) obtained from the corporate IH person were discounted. It was argued that the data were suspect and inconsistent with low measurements. While that may be true, such disagreement would logically mandate retesting, which was never performed. Since wood-treating plants do not monitor these fugitive air emissions, we argue that conservative calculation methods are the best approach to determining risks from exposure. We do not think that it is reasonable to apply calculations that are known to underpredict mass emissions, as has been the practice of the industry since the TRI program began. The purpose of TRI reporting is to keep the public informed of potentially dangerous emissions and to benchmark and monitor industry efforts to reduce emissions. The fugitive emissions reported by wood treaters are not within the spirit of TRI and are not reflective of accurate and transparent reporting based on the above observations. While we do not believe the foregoing recommended calculation method is precise, we do think that it offers reasonable conservatism for estimating emissions. It is the responsibility of wood-treating facilities to confirm by measurement and monitoring what their true emissions are and to verify whether their calculation procedures are representative of the emissions resulting from their operations. Unless facilities bother to make actual measurements, they should be obliged to make calculations that possibly err on the high side in

Air pollution from wood treatment

93

order to allow for reasonable safety margins when assessing community and worker exposures. To calculate the most probable fugitive mass emissions, we recommend the use of AP-42 emission factors for those chemicals reported in Table 4.2. Equation (4.3) is also recommended to account for temperature effects for naphthalene emissions. To calculate the most probable fugitive mass emissions for other PAHs where no emission factors are reported in AP-42, we recommend that the emission factors reported in Table 4.1 be applied, but that calculated mass emissions be multiplied by factors of 5 and 143 to represent lower and upper bounds of probable emissions. The use of a range for probable emissions can be used as a basis to assess possible impacts on community exposures to varying degrees.

Factors influencing precision of mass emission calculations In addition to unreliable and incomplete emission factors, other parameters that influence the calculations are skin temperature, treated wood stacking configuration, and handling practices. The US Forest Service (1963) has published a study on the skin temperature of wood exposed to direct sunlight. Temperatures as high as 170–179 F (350– 355 K) on exposed roof shingles have been recorded. Such temperature levels are generally exceptions but may last an hour or more each day, with more typical temperatures of between 160–169 F (344–349 K) for 20 hours and 150– 159 F (339–344 K) for 43 hours. When freshly treated wood is subjected to elevated temperatures, it is logical that the vapor pressures of the PAHs increase and they become more volatile. It is also logical that higher skin temperatures will tend to increase the pore diffusion rate of chemicals. As noted by the correlations in Table 4.2, emissions actually reach a state of equilibrium and there is a steady-state level by which volatilization may continue for up to 90 days or slightly beyond. AP-42 emission factor expressions are empirical correlations that are based on an average fit of data. They are not precise enough to discriminate between temperature effects that are most critical during the first several hours and days when treated wood surfaces are still wet with chemicals from treatment. Since vapor pressure (see Chapter 3) is temperature dependent, assuming wood to be at an equilibrium temperature with ambient conditions is not a reasonable assumption when calculating fugitive air emissions resulting from surface volatilization. A simple analogy is to walk across your backyard deck barefoot on a sunny day. Readers who have done so will recognize that the soles of one’s feet will feel scorched and burned despite the fact that the surrounding air is temperate. That is because heat is absorbed by the deck. Assuming that exposed wood surfaces are at ambient temperature conditions when performing fugitive emission calculations leads to conservatively low emission estimates and subsequent under-reporting. To illustrate this further, consider Table 4.4, which compares the vapor pressures for different PAHs that

94

Handbook of Pollution Prevention and Cleaner Production

Table 4.4 Effect of temperature on PAH volatility Temperature (8K) Chemical

298 (ambient)

350 (skin temperature)

Relative volatility

Fluorene Acenaphthylene Acenaphthene Pyrene Benzo[a]phenanthrene 9,10-Benzophenanthrene Anthracene Benzo[a]pyrene Perylene Fluoranthene Naphthalene

6.645E02 5.356E01 3.052E01 3.919E04 2.400E06 1.539E06 9.153E04 7.735E07 6.229E08 8.271E04 3.442E01

1.313Eþ01 4.592Eþ01 3.415Eþ01 1.800E01 1.747E03 2.257E03 3.138E01 9.069E04 1.439E04 4.388E01 2.179Eþ00

198 86 112 459 728 1466 343 1172 2311 531 6

make up creosote. The last column is the relative volatility (ratio of vapor pressures at the two temperatures). The comparison shows that vapor pressure and hence volatility increases by many orders of magnitude when we consider the skin temperature of wood that has been treated. Skeptics may argue that even several-order-of-magnitude increases in vapor pressure still result in very low levels of volatilization because the values are so low to begin with. This is indeed a valid observation, but it ignores surface area effects. Fugitive mass emissions are a function not only of temperature and the vapor pressures of the chemicals in question, but the surface area available for vaporization. Consider your cup of coffee – the open surface of the cup is the only area exposed to the surrounding atmosphere and hence the rate at which the liquid cools and evaporates into the room is controlled by ambient temperature conditions, the temperature of the liquid, and a well-defined open cup surface area. But if you tip the cup over and spill the coffee on the table, the surface area exposed to the room’s atmosphere is now many times greater and hence the rate of volatilization increases accordingly. AP-42’s guidance on surface area available to volatilization is inadequate to say the least. We must remember that this publication has been around since the 1990s, and apparently no guidance was provided before AP-42. Essentially the US EPA guidance is the following. Considering the total surface area of treated wood as a basis to calculate emissions is reported to be inaccurate because it would grossly overstate the true surface area of exposure. It is argued that wood is stacked in tight configurations and therefore the exposed surface areas available for volatilization to occur are a small fraction of the actual areas exposed to the atmosphere (see photographs in Chapter 3, for example). It is therefore recommended that the effective surface area be calculated by assuming

Air pollution from wood treatment

95

10% of the total surface area of wood treated. AP-42 goes on to say that assuming 10% of the total surface area of treated wood is likely too conservative, but then offers no alternative. The problem with this guideline is that it ignores the handling practices at wood-treating facilities – not surprising since practically all of the information found in AP-42 is based on information provided by the industry itself. The industry has omitted the fact that treated wood very often does not remain in a tightly packed configuration. A detailed study of the wood-handling practices of the Somerville Tie Plant shows that historically it maintained very low inventories of treated wood in its stockyards, and had a practice of breaking tramloads of treated wood down and loading them on to gondola cars virtually on the day of production. Belt feeders were used such that treated ties were individually fed along belt feeders and loaded into railcars, and in doing so ties tumbled and rolled, exposing entire surfaces. A pole plant owned by Roy O. Martin in Louisiana was examined. Here we found that treated poles were laid out side by side in stockyards (see the aerial photograph in Figure 4.1). There is no possible way that 10% of the total surface area is representative of the actual exposed surface area available for volatilization to occur with such a stacking configuration. The effective area in this example is closer to 70%. Handling practices that have an effect on surface area exposure are not simply related to stacking configuration. How the facility handles the treated product and how quickly it loads and transports the product impact on exposed surface

Figure 4.1 A pole plant where treated poles are staged side by side.

96

Handbook of Pollution Prevention and Cleaner Production

areas and subsequent emissions. If low inventories are maintained and stacking configurations are broken down, then the treated product is in motion continually, exposing large surface areas. Many facilities match their productions to the needs of customers through specialty orders. Not all treaters make only poles or only railroad ties. Lumber and specialty products have different configurations, require different handling procedures, and require different standing inventories. Let’s take an example of a plant that makes 700,000 railroad ties per year (a medium-sized plant). Assuming all the ties made are to a standard railroad tie dimension, then the total surface area of the wood made over a year is 17,178,000 ft2 (a single ties has a total surface area of about 24.5 ft2). This is equivalent to about 47,063 ft2 per day. But if we assume that only 10% of the surface area represents the exposed area for volatilization to occur, then there is only 4706 ft2 from which vapors may become mobile in the atmosphere. This smaller surface area is not necessarily troublesome except when we consider the fact that treating cycles may vary between 7 and 22 hours depending on the treater’s operating conditions. Hence, every time treated wood is pulled from a series of retorts, another 4706 ft2 of surface area is exposed. Each fresh surface area displays the maximum emissions because the wood is warm and coated with treating chemicals. And if the treated product is broken down from its configuration on the trams within several hours or more, as is the practice at many facilities, the exposed surface areas are many times greater and at peak emissions. Wood treaters do not make these practices apparent in their emissions reporting. AP-42 does not even consider these factors – not surprising since the basis for AP-42 calculations is what the industry itself reports. To illustrate to the reader the importance of the factors that impact on the precision of mass emission calculations, Table 4.5 shows a set of sample calculations in which a comparison is made between AP-42’s computation procedures and those offered in this chapter. Remember that the EPA’s method only accounts for a few PAHs, does not account for the skin temperature of the wood, and recommends that 10% of the total wood surface area be used as the effective area. The difference between the total PAH emissions between the two methods is a factor of 2 using the most conservative basis of the calculation method described in this section. At the upper bound of emission estimation, the total mass emissions are nearly 28 times greater than those estimated using the AP-42 guidance document. In our opinion these differences are unreasonable. The industry has both a moral and statutory obligation under the TRI program to report emissions as accurately as possible. Accurate emissions can only be determined by measurement and monitoring. Since the industry does not invest in air quality measurement instrumentation and does not generally perform monitoring, it should be obliged to rely on conservative calculation methods. By conservative, we mean relying on assumptions that may tend to overestimate emissions. Public health officials in the USA and most other countries have argued for more than a generation that it is better to err on the side of caution than to run the risk of

Air pollution from wood treatment

97

Table 4.5 Comparison between two methods of calculated fugitive emissions Pollutant

AP-42 method (lb)

Lower bound estimatea (lb)

Upper bound estimatea (lb)

Benzene Toluene Ethylbenzene m- and p-Xylene o-Xylene Isopropylbenzene Benzonitrile Phenol Naphthalene 2-Methylnaphthalene 1-Methylnaphthalene Biphenyl 1-Ethylnaphthalene 2,6-Dimethylnaphthalene 1,2-Dimethylnaphthalene Benzofuran Phenanthrene Fluoranthene Benzo[b]thyophene Acenaphthylene Acenaphthene Fluorene Anthracene Pyrene 2-Methylnaphthalene 1-Methylnaphthalene Total

– – – – – – – – 22,411 – – – – – – – 2665 203 – 139 3901 2189 176 34 – – 31,719

673 2368 2359 10,163 1162 1415 641 2331 22,411 1496 214 1260 63 153 116 99 2665 203 33 139 3901 2189 176 34 3596 1442 61,305

19,244 67,737 67,481 290,674 33,239 40,480 18,318 66,661 22,411 42,790 6119 36,033 1795 4363 3331 2844 2665 203 952 139 3901 2189 176 34 102,856 41,246 877,882

a

The following assumptions were used in model calculations. The facility in this example is located in Louisiana. For temperature effects the following apply: 1. 2. 3.

Seasonal temperature effects were accounted for by consulting the monthly average temperatures for the city the facility is located in (http://www.losc.lsu.edu/cgi-bin/newsmonthly.py). The facility stockpiles its treated wood largely in rows in uncovered areas. Wood skin temperatures were accounted for by adding 40 F to mean ambient temperature conditions. When treated wood is removed from the treating cylinders it is at a temperature close to the conditions within the retort. It is also in a tightly packed configuration, and takes many hours to almost a day to equilibrate with ambient air conditions as it sits on the drip pad. Therefore, a temperature of 175 F was assumed for the first day from which a charge of poles has been removed from the cylinders.

For exposed surface area effects the following apply: 1. 2.

3.

For the first day of production in a month it was assumed that the treated wood was staged at the drip pad in a tightly packed configuration and had an effective surface area of 10%. It is assumed all treated products (poles) are shipped on 30-day cycles. No inventory is maintained on site, and the treated poles are held in the stockyard until the end of the month. The wood is assumed to have an effective surface area of 70% based on field stockpile observations. At the end of the month, the treated wood is loaded on to flat beds. During this process 100% of the surface area is exposed for vaporization. The model computation assumes all shipping is performed in a single day.

98

Handbook of Pollution Prevention and Cleaner Production

chemically induced illnesses. Relying on a conservative approach enables facilities to benchmark air emissions and to establish targets of reduction using controls and pollution prevention. However, the industry has no incentive to do this, because if it reported higher emissions than calculated by the methods entrenched in AP-42, pollution fees would increase, the public would become more educated and aware, and facilities would have to invest in pollution controls and possibly more costly practices to reduce emissions.

4.3.3

Process emission factors

Section 10.8 of AP-42 provides process emission factors. No attempt has been made to assess the accuracy of the method. We only restate the method below so that the reader has a single source from which to prepare an air emissions inventory. The reader can refer to the following tables in AP-42 (Section 10.8): Tables 4-7–4-12. It may be surprising to see that emission factors are generally based on only a couple of measurements without any indication as to whether controls were used or not. Table 4-12 in AP-42 is a summary of the creosote woodpreserving emission factor data. The four steps in the empty-cell treatment process during which emissions occur are: conditioning, preservative filling/air release, preservative return/blowback, and vacuum. The EPA states in Section 10.8 that no complete sets of data exist for all four steps for any of the pollutants. For example, there are VOC emission data for the conditioning (Boulton) and preservative return/blowback steps only; for naphthalene, there are emission data for the conditioning (Boulton), preservative filling/air release, and vacuum steps only. To provide estimates of the emission factors for the complete empty-cell process, the EPA filled the data gaps for each pollutant using ratios of the emission factors for process steps for which data were available as follows: 1. For conditioning, the emission factor data gaps were filled by dividing the preservative filling/air release value by the average of the ratios of the preservative filling/ air release values to the conditioning values; this average equals 0.0337. For example, for fluoranthene, the conditioning value was estimated as: (2.0  108)/ (0.0337) ¼ 5.9  107. 2. For preservative filling/air release, the EPA filled the emission factor data gaps by multiplying the preservative filling/air release value by the average of the ratios of the preservative filling/air release values to the conditioning values; this average equals 0.0337. For example, for VOCs, the preservative filling/air release value was estimated to be: (5.1  103)  (0.0337) ¼ 1.7  104. 3. For preservative return/blowback, the EPA filled the emission factor data gaps by multiplying the conditioning value by the ratio of the preservative return/blowback value to the conditioning value for VOCs; this ratio equals 0.0131. For example, for anthracene, the preservative return/blowback value was estimated to be: (1.1  107)  (0.0131) ¼ 1.4  109.

Air pollution from wood treatment

99

4. For the vacuum step, the emission factor data gaps were filled by multiplying the preservative filling/air release value by the average of the ratios of the preservative filling/ air release values to the vacuum step values; this average equals 2.93. For example, for pyrene, the vacuum step value was estimated to be: (1.7  108)  (2.93) ¼ 5.0  108.

If the reader is confused and wonders what kind of accuracy is possible from the above estimates (especially since in most cases only two values were available for each pollutant), be comforted by the fact that you are not alone. The woodpreserving industry has been operating in the USA for well over 100 years and yet has recorded only a handful of emissions to constitute emission factors that have no real statistical significance. Quantifying air emissions appears not to be a priority for the AWPI and its industry supporters. Table 4-13 in AP-42 shows the emission factors for each step in the process for each pollutant for which test data were available to the EPA. Table 4-14 is the same table with the additional emission factors that were estimated using the gap-filling procedures described above. Table 4-14 also shows the emission factors for the total treatment process with and without conditioning by the Boulton process. These emission factors for the total process are the sum of the factors for the individual steps in the process. These data are summarized in Table 4.6. The emission factors reported in the table are mass emissions in pounds per cubic foot of wood treated. The emission factors reported by the EPA in Table 4.6 are also a concern because we are not convinced that they include the fugitive emissions that occur when cylinder doors are opened and closed during the treatment process, and there are no provisions in TRI reporting that require treaters to report and monitor situations when cylinder door seals leak or unexpected releases from ruptured cylinder door seals occur. Some of the photographs in Chapter 3 show that significant emissions occur when wood is removed from cylinders and when fresh charges are made immediately after unloading. The US EPA (DaRos et al., 1982) has measured fugitive emissions that occurred from cylinder spillage and vapors released during unloading/charging operations. It has noted that these sources are close to employee work areas. The EPA collected air samples directly above the access doors during unloading/ charging using EPA Method 5 and XAD-2 cartridges; the fugitive emissions released were reported to appear as a dense white plume (see Figures 3.17 and 3.18 in Chapter 3). The EPA also obtained grab samples from a vacuum vent common to both PCP and creosote treating cylinders, which were analyzed on site for total hydrocarbons. The grab samples were also tested for low-molecular-weight hydrocarbons, including benzene, toluene, and ethylbenzene. Significant concentrations of organic compounds were reported to be emitted. The vacuum vent was determined as the greatest fugitive air emission source, with rates varying from 0 to 360 g/min of organics. The reader may again refer to Section 10.8 for process emission factors for the CCA process. Those emission factors are even more mysterious than for creosote, and essentially report negligible emissions.

100

Table 4.6 Summary of EPA process emission factors for empty-cell processesa Total without conditioning

6.7E05 1.2E07 3.4E07 1.4E09 1.5E09 1.4E09 5.5E10 7.4E10 3.3E08 7.8E10 4.3E07 7.8E09 5.0E08 9.7E07 2.1E08 6.6E09

5.0E04 3.8E07 4.4E07 3.9E09 1.1E08 1.1E08 4.1E09 5.6E09 2.5E07 3.5E09 1.0E06 5.9E08 2.3E08 3.0E06 2.1E07 5.0E08

5.8E03 9.9E06 2.8E05 1.3E07 1.4E07 1.3E07 4.8E08 6.4E08 2.9E06 6.7E08 3.5E05 6.8E07 3.9E06 7.9E05 1.9E06 5.8E07

7.4E04 6.3E07 1.7E06 1.6E08 1.6E08 1.6E08 6.1E09 8.2E09 3.7E07 8.4E09 1.8E06 8.7E08 7.8E08 4.6E06 2.8E07 7.4E08

6.9E05

5.1E04

6.0E03

7.5E04

Pollutant

Preservative filling/air release

Preservative return/ blowback

VOCs Acenaphthene Acenaphthylene Anthacene Benzo[a]anthracene Benzo[b]flouranthene Benzo[k]fluoranthene Benzo[a]pyrene Carbazole Chrysene Dibenzofuran Fluoranthene Fluorene Naphthalene Phenanthrene Pyrene

5.1E03 9.3E06 2.6E05 1.1E07 1.2E07 1.1E07 4.2E08 5.6E08 2.5E06 5.9E08 3.3E05 5.9E07 3.8E06 7.4E05 1.6E06 5.1E07

1.7E04 1.3E07 8.7E07 1.1E08 3.9E09 3.7E09 1.4E09 1.9E09 8.4E08 4.1E09 4.1E07 2.0E08 4.9E09 6.2E07 4.8E08 1.7E08

Total

5.3E03

1.7E04

a

3

Emission factors in units of lb/ft of wood treated. Does not include emissions from preservative return/blowback associated with Boulton process.

b

Handbook of Pollution Prevention and Cleaner Production

Vacuum

Total with conditioning by Boultonb

Conditioning by Boulton processb

Air pollution from wood treatment

101

For guidance on procedures for estimating emissions from PCP emissions, one may travel along the same path as Sir Percival in search of the Holy Grail. We have not been able to identify any authoritative studies that report emission factors for wood treatment using PCP. The European Union has relied on the UK National Emissions Inventory (http://www.airquality.co.uk/reports/empire/naei/ annreport/annrep96/sect6_2.htm). The UK relies on an emission factor of 3% of the wood content used in the production of treated wood to estimate annual emissions (i.e. 3% of PCP used in wood production is assumed to be lost to volatilization). There is one study (Ingram and Tarlton, 2005) on PCP use that is widely cited. This paper contains a review of the literature related to vaporization of organic wood preservatives, PCP, and creosote from treated samples of lumber. These studies are related to the effects of temperature, carrier solvents, coatings, and other experimental parameters. A re-examination of the results from experiments related to temperature effects on the vaporization of organic wood preservatives from treated wood is also included. A semi-empirical equation that correlates the boiling point of creosote components and PCP with air concentrations of test specimens at different temperatures is described. One of the important observations from this study was that vaporization of PCP was lower for samples where P9 Type A oil was the carrier solvent. The other important observation in this study was that a 20–30 C increase in temperature resulted in a three- to fourfold increase in airborne PCP concentration. This observation indicated that PCP evaporated from the surface of the treated wood into the surrounding atmosphere at a rate related to the partial vapor pressure of PCP. The measured concentrations of PCP in air followed the pressure–temperature relation as predicted by the Clausius– Clapeyron relation described in Chapter 3. The study, however, is not useful for extracting emission factors.

4.3.4

Emissions from support equipment and piping components

DaRos et al. (1982) reported that fugitive emissions from valves and fittings occur during transfer of preservative formulation, raising concerns that these incidents occur in areas where workers may be exposed. Figures 3.12 and 3.14– 3.16 in Chapter 3 illustrate that not much has changed since 1982, since our photographs were taken at wood-treating plants in 2008 and 2009. The US EPA Protocol, dated November 1995, entitled 1995 Protocol for Equipment Leak Emission Estimates (EPA-453/R-95-017, ‘‘the 1995 EPA Protocol’’) presents four different methods for estimating equipment leak emissions. The methods, in order of increasing refinement, are:    

Method Method Method Method

1: Average Emission Factor Method. 2: Screening Value Range Method. 3: Correlation Equation Method. 4: The Unit-specific Correlation Equation Method.

102

Handbook of Pollution Prevention and Cleaner Production

In general, a more refined method requires more data and provides more reliable fugitive hydrocarbon emission estimates. It is also more costly to implement and hence is not relied upon. In the Average Emission Factor Method and the Screening Value Range Method, emission factors are combined with equipment counts to estimate emissions. This is the least-cost methodology. To estimate emissions with the Correlation Equation Method, organic vapor analyzer (OVA)-measured concentrations (screening values) for all equipment components are individually entered into correlation equations or counted as either default zeros or pegged components. In the Unit-specific Correlation Equation Method, screening and actual mass emissions are measured for a select set of individual equipment components at a site and then used to develop unit-specific correlation equations and pegged source factors. Screening values for all components are then entered into these unit-specific correlation equations and pegged source factors to estimate emissions. The four different methods of the US EPA can be applied and used to estimate fugitive emissions. Detailed discussion of the methods is presented in the 1995 EPA Protocol. Another source is the American Petroleum Institute (API) document, dated July 1997, entitled Calculation Workbook for Oil and Gas Production Equipment Fugitive Emissions, which provides step-by-step example calculations using each of the estimation methods outlined in the 1995 EPA Protocol. However, some of the factors and correlation equations associated with the first three methods have been corrected and revised. Method 4 is not affected because it calls for the collection of site-specific data that are then used to develop unit-specific correlation equations and factors. Component counting, component screening, and leak quantification must use the methods specified in Sections V, VI, and VII of the guidelines for the unit-specific equations and factors to be acceptable to the local districts.

Method 1: Average Emission Factor Method This method is recommended by the EPA when no reliable screening data are available. However, we fail to see why wood-preserving plants cannot generate an accurate inventory of emission sources and perform screening audits. There are no technological reasons for a facility not to be able to generate such information. The following five steps are used: 1. Components are separated into types such as nonflange connectors, flanges, openended lines, pump seals, valves, and other components. 2. Each component type is further separated into service types such as gas, light liquid, or heavy liquid if there are different emission factors for each service type. 3. The total number of components in each group (component type/service type) is then determined. 4. The number of components in each group is multiplied by the corresponding average emission factor to obtain the subtotal of emissions from the group. 5. The subtotals of emissions from all groups are then added to provide the total emissions from the facility.

Air pollution from wood treatment

103

Tables 4.7 and 4.8 provide some emission factors for different equipment. The emission factors are expressed in scientific notation, which means that the decimal point has been moved. If the exponent is negative, move the decimal point to the left. If the exponent is positive, move the decimal point to the right. If the exponent is zero, the decimal point does not move. For example, if a number is expressed as 2.0E1, move the decimal point one place to the left to get 0.20. If a number is expressed as 2.0þE2, move the decimal point two places to the right to get 200. If a number is expressed as 2.0þE0, the decimal point does not move. The number is 2.0. The precision of the calculation procedures depends on the accuracy of the emissions source inventory as well as how representative the emission factors are of a particular facility. AP-42 notes that emission factors can be site specific and depend on the age and condition of equipment, as well as the level of maintenance required to maintain it in operating conditions.

Method 2: Screening Value Range Method The Screening Value Range Method was formerly known as the Leak/No Leak Method. This method uses the screening data (instrument screening values, ‘‘SVs’’) to calculate the mass emission rates based on the component leak level (below 10,000 ppm ¼ no leak; 10,000 ppm or greater ¼ leak). Some parts of the USA define leaks at levels lower than 10,000 ppmv. A region may choose to apply the 10,000 ppmv emission factors to all components above their leak definition. Such a policy will generally result in a conservative estimation of emissions. The California Air Pollution Control Offices Association (CAPCOA) recommends that facilities that record individual screening values for each component may prefer to use the Correlation Equation Method (Method 3) or the Unit-specific Correlation Equation Method (Method 4). The application of Method 2 (Screening Value Range) requires the completion of the following five steps: 1. Components are separated into types (i.e. nonflange connectors, flanges, open-ended lines, pump seals, valves, others). 2. Each component type is further separated into service types (gas, light liquid, or heavy liquid) if there are different emission factors for the service types. 3. The total number of components in each group (component type/service type) with screening values below 10,000 ppmv is determined. The total number of components in each group with screening values of 10,000 ppmv or more is then determined. 4. The number of components in each subgroup (component type/service type/screening value range) is multiplied by the corresponding screening value range factor to obtain the subtotal of emissions from the subgroup. 5. The subtotals of emissions from all subgroups are added to give total emissions from the facility.

The reader may refer to the CAPCOA publication for emission factors from other emission source types. The facility needs to maintain an accurate

104

Table 4.7 Emission factors for natural gas-fired enginesa Description Standard ‘‘rich-burn ’’ engines May include:  Natural gas process heaters  Natural gas production, compressors  Natural gas production, flares excluding SO2

Emission factor

Control efficiency

CO NOx PM10 PM2.5 SO2 VOCs

3794 lb/MMCF natural gasb 2254 lb/MMCF natural gasb 9.69 lb/MMCF natural gasb 9.69 lb/MMCF natural gasb 0.60 lb/MMCF natural gasb 30.2 lb/MMCF natural gasb

Three-way catalyst CO – 80%c NOx – 90%c VOCs – 50%c

CO NOx PM10 PM2.5 SO2 VOCs

568 lb/MMCF natural gasb 4162 lb/MMCF natural gasb 0.079 lb/MMCF natural gasb 0.079 lb/MMCF natural gasb 0.60 lb/MMCF natural gasb 120.4 lb/MMCF natural gasb

Oxidation catalyst CO – 80%c VOCs – 50%c

a Report all ‘‘standard’’ engine emissions together, and report all ‘‘lean-burn’’ emission engines together. For facilities with both ‘‘standard’’ and ‘‘lean-burn’’ emission engines, report ‘‘standard’’ engines and ‘‘lean-burn’’ emission engines as separate emission units. Split the total fuel gas between the two different types of engines based on your best estimate of the relative amount of fuel burned in each type of engine at the facility. Group all natural gas combustion equipment with standard ‘‘rich-burn’’ or lean-burn engines. For example, you may group all standard ‘‘rich-burn’’ engines, natural gas process heaters, production compressors, and flares together. b The emission factors listed are derived from AP-42 Chapter 3.2 (Tables 3.2-2 and 3.2-3). c The control factors listed above can only be used if documentation is on file showing that the catalyst was inspected and maintained. If actual control efficiencies are different than those listed above, use the actual control efficiency. Source: obtained from the Michigan Department of Environmental Quality, Fact Sheet No. 9845 (Rev. 10/2006).

Handbook of Pollution Prevention and Cleaner Production

‘‘Lean-burn’’ engines May include:  Natural gas process heaters  Natural gas production, compressors  Natural gas production, flares excluding SO2

Pollutant

Air pollution from wood treatment

105

Table 4.8 Emission factors for various equipment Description

Pollutant

Emission factor

Control efficiency

CO NOx PM10 SOx VOCs

35 lb/MMCF natural gas 140 lb/MMCF natural gas 3.0 lb/MMCF natural gas 0.6 lb/MMCF natural gas 2.8 lb/MMCF natural gas

VOCs

36 lb/1000 gal-year crude oil (storage capacity)

Vapor recovery system – 95% Flare – 95%

VOCs

1.1 lb/1000 gal crude oil (throughput)

Vapor recovery system – 95% Flare – 95%

VOCs

2.0 lb/1000 gal crude oil

Vapor recovery system – 95%

Process heatersa

Tank storageb Fixed roof tank – breathing loss Fixed roof tank – working loss Truck loading

a

Process heaters include process heaters as a separate emission unit if they were not grouped with natural gas-fired engines. The emission factors for process heaters come from the US EPA’s Factor Information Retrieval (FIRE) data system, which can be accessed at http://cfpub.epa.gov/oarweb/ index.cfm?action¼fire.main. (Emission factors from Chapter 1.4 (Table 1.4-1) of the US EPA’s AP42 Compilation of Air Pollutant Emission Factors may also be used to calculate emissions from process heaters.) b You may also use the US EPA Tanks 4.0 software to estimate emissions from tank storage. This software can be downloaded at www.epa.gov/ttn/chief/software/tanks/index.html. Source: obtained from the Michigan Department of Environmental Quality, Fact Sheet No. 9845 (Rev. 10/2006).

inventory and should verify that emission factors are representative of the facility, the latter of which is not a requirement among the standards. Facilities do not have a standardized procedure for monitoring and classifying leaks and fugitive emissions, which introduces additional sources of errors into the inventory.

Method 3: Correlation Equation Method This method is based on the application of values presented in Table 4.9. The following are recommended guidelines published in the CAPCOA guidance document: 

Default zero factors should apply only when the screening value, corrected for background, equals 0.0 ppmv (i.e. the screening value is indistinguishable from the background reading).

106

Handbook of Pollution Prevention and Cleaner Production

Table 4.9 1995 EPA correlation equations and factorsa

Component Default zero type/service type factor (kg/h)b Valves/all Pump seals/all Othersf/all Connectors/all Flanges/all Open-ended lines/all

7.8E06 1.9E05 4.0E06 7.5E06 3.1E07 2.0E06

Pegged factor (kg/h)d

Correlation equation (kg/h)c

10,000 ppmv 100,000 ppmv

2.27E06(SV)^0.747 5.07E05(SV)^0.622 8.69E06(SV)^0.642 1.53E06(SV)^0.736 4.53E06(SV)^0.706 1.90E06(SV)^0.724

0.064 0.089 0.082 0.030 0.095 0.033

0.138 0.610e 0.138 0.034 0.095 0.082

a Technical corrections and adjustments were made to the refineries and marketing terminals bagged data, obtained by use of the blowthrough method, to account for the hydrocarbon leak flow rate. b The default zero factors apply only when the screening value (SV), corrected for background, equals 0.0 ppmv (i.e. the screening value is indistinguishable from background reading). The default zero factors were based on the combined 1993 refinery and marketing terminal data only; default zero data were not collected from oil and gas production facilities. c The correlation equations apply for actual screening values, corrected for background, between background and 9999 ppmv, and can be used for screening values up to 99,999 ppmv at the discretion of the local district. d The 10,000 ppmv pegged factors apply for screening values, corrected for background, equal to or greater than 10,000 ppmv, and are used when the correlation equations are used for screening values between background and 9999 ppmv. The 100,000 ppmv pegged factors apply for screening values reported pegged at 100,000 ppmv and are used when the local district authorizes use of the correlation equations for screening values between background and 99,999 ppmv. e Only three data points were available for the pump seals 100,000 ppmv pegged factor. f The ‘‘other’’ component type includes instruments, loading arms, pressure-relief valves, vents, compressors, dump lever arms, diaphragms, drains, hatches, meters, and polished rod stuffing boxes. This ‘‘others’’ component type should be applied for any component type other than connectors, flanges, open-ended lines, pumps, or valves. However, if an acceptable emission estimate exists that more accurately predicts emissions from the source, then that emission estimate applies (e.g. positiveflowing junction boxes in SCAQMD). Source: SBCAPCD Report, dated 1 May 1997, entitled Review of the 1995 Protocol: The Correlation Equation Approach to Quantifying Fugitive Hydrocarbon Emissions at Petroleum Industry Facilities.







The correlation equations apply for actual screening values, corrected for background and 9999 ppmv, and should be used for screening values up to 99,999 ppmv at the discretion of the local district. The 10,000 ppmv pegged factors apply for screening values, corrected for background, equal to or greater than 10,000 ppmv, and should be used when the correlation equations are used for screening values between background and 9999 ppmv. The 100,000 ppmv values are used when the local district authorities use the correlation equations for screening values between background and 99,999 ppmv. Where multiple instrument screening values apply as with quarterly inspections, the average of the calculated mass emission estimates during the reporting period should be used.

Air pollution from wood treatment

107

The following steps are applied in this method: 1. Record each individual component screening value. 2. Group the data component type into three categories of screening ranges: default zeroes range, correlation equations range, and pegged source range. 3. Multiply the number of components with instrument screening values in the default zeroes range by the appropriate default zero factors. 4. Enter each individual component screening value that is within the correlation equations range into its appropriate correlation equation. 5. Multiply the number of components with instrument screening values in the pegged range by the appropriate pegged values. 6. Sum up all the calculated emissions to obtain an estimate of the total emissions from the facility.

The CAPCOA guidance document provides a detailed example that the reader may refer to. This method is believed to be more accurate than the previous two methods but is cumbersome to apply.

Method 4: The Unit-specific Correlation Equation Method This method requires the facility to collect site-specific data that are then used to develop unit-specific correlation equations and factors. These are subject to approval by state regulatory agencies. In principle we believe this to be the most precise method because the facility essentially develops a site-specific emission factor or correlation for emission factors that is specific to the equipment and controls. This type of empirical approach is reasonable and is analogous to the development of control equations that are generally used throughout the chemical industry in guiding operators in the control of chemical reactors. Generally the development of such empirical correlations that can then be applied to standard emission calculations that are well documented for different types of components like valves, diaphragms, seals, and flanges implies further that the empirical correlations will have well-defined statistics such as mean, standard deviation, range, and confidence limits. Examples of published empirical correlations include the various API (1987, 1991, 1996, 1997) algorithms for determining evaporation losses from storage tanks and product loading/unloading terminals, and leak-rate correlations for converting leak screening data to emissions rates (US EPA, 1995; GRI Canada, 1998). But these published correlations carry with them the same inherent flaws that accompany emission factors themselves; in other words they are based on average reported values and are not necessarily representative of a facility. We are still faced with applying an underlying assumption that on average the calculated emissions are the same for any one facility and only production rates influence the amount of emissions. In all of these methods (and indeed this is the basis for applying AP-42) on average all facilities will generate the same amount of pollution per unit of production since the manufacturing and control technologies are

108

Handbook of Pollution Prevention and Cleaner Production

approximately the same. Because the industry appears to rely almost entirely on calculations that use average emission factors that are not verified as being site specific, we have concluded that there is gross under-reporting of fugitive emissions.

4.3.5

Emissions from kilns

Kiln drying is a process that results in green or (semi-) air-dried wood being stacked into large rooms or containers, which are then raised to high temperature (>212 F) to drive off the moisture in the wood. During the drying process, VOCs are also expelled. Thus the process results in the emission of VOCs from the kiln and emissions from the fueling operation, which are often gas or distillate oil. Estimates should be made, therefore, for both of these pollutants. There are few reliable emission factors reported in the literature. Emission factors generally must be developed by actual testing of kiln units. Emissions are also dependent on the wood species. A draft memo published by the North Carolina Department of Air Quality (NC DENR, 1998) reports emission factors of 2.11 pounds of VOC per 1000 board feet for steam-heated kilns for pine and 0.211 for hardwood; however, it states that these are extrapolations and in lieu of more precise information recommends a general emission factor of 3.4 pounds of VOC per 1000 board feet for steam-heated kilns, based on limited tests of a plant it cited. Another study published in the Forest Products Journal (Milota, 2000) reported 1–4 lb of total organic emissions per 1000 board feet of softwood lumber. Forintek Canada Corp. prepared a Power Point presentation summarizing the state of knowledge of kiln emission factors (http://www.forestprod.org/ drying06barry.pdf). The company reported that hazardous air pollutants emitted during kiln drying include acetaldehyde, acrolein, benzene, ethanol, formaldehyde, methanol, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), toluene, and other chemicals. While some emission factors are reported in their presentation, they are mill specific and are not recommended for calculation purposes. The Forintek presentation provides hazardous air pollutant relative abundances of different species (Table 4.10). Emissions from kilns and dryers include wood dust and other solid particulate matter (PM), VOCs, and condensable PM. If direct-fired units are used, products of combustion such as carbon monoxide (CO), carbon dioxide (CO2), and nitrogen oxides (NOx) are also emitted. The condensable PM and a portion of the VOCs leave the dryer stack as vapor but condense at normal atmospheric temperatures to form liquid particles or mist that creates a visible blue haze. Both the VOCs and condensable PM are primarily compounds evaporated from the wood, with a smaller constituent being combustion products. Quantities emitted are dependent on wood species, dryer temperature, fuel used, and other factors including season of the year.

Air pollution from wood treatment

109

Table 4.10 Relative abundance (%) of hazardous air pollutants Wood species

Acetaldehyde

Acrolein

Ethanol

Formaldehyde

Methanol

Lodge pine Black spruce White spruce

6.62 17.16 8.38

0.22 0.15 0.23

3.56 1.82 4.34

0.34 0.71 0.93

4.71 12.69 12.31

Average

10.72

0.20

3.24

0.66

9.90

The PM and PM10 emissions from strand dryers can be controlled with an electrified filter bed (EFB) and a wet electrostatic precipitator (WESP). These electrostatic control devices provide efficient control of PM and PM10, but lesser control of condensable organic pollutants in the exhaust streams from dryers. Regenerative thermal oxidizers (RTOs) can be used to control emissions of VOCs and condensable organics from strand dryers or veneer dryers. An RTO can also control emissions of CO from direct-fired dryers. Thermal oxidizers destroy these pollutants by burning them at high temperatures. The RTOs are designed to preheat the inlet emission stream with heat recovered from the incineration exhaust gases. Up to 98% heat recovery is possible, although 95% is typically specified. Gases entering an RTO are heated by passing through preheated beds packed with a ceramic medium. A gas burner brings the preheated emissions up to an incineration temperature between 788 and 871 C (1450 and 1600 F) in a combustion chamber with sufficient gas residence time to complete the combustion. Combustion gases then pass through a cooled ceramic bed, where heat is extracted. By reversing the flow through the beds, the heat transferred from the combustion exhaust air preheats the incoming gases to be treated, thereby reducing auxiliary fuel requirements. The above information may be applied to developing approximate fugitive emissions from the kiln itself. Separate computations for the fueling operations should also be made using methodology and emission factors provided in AP42’s section on combustion and fueling operations.

4.3.6

Tank emissions

Tank emissions are a point source at any facility. Section 7 of AP-42 describes procedures and emission factors for estimating emissions. The emission-estimating equations presented in Section 7.1 were developed by the American Petroleum Institute (API). The API retains the copyright to these equations, but has granted permission for the non-exclusive, noncommercial distribution of this material to governmental and regulatory agencies. However, the API reserves its rights regarding all commercial duplication and distribution of its material. Therefore, the material presented in Section 7.1 is available for public

110

Handbook of Pollution Prevention and Cleaner Production

use, but the material cannot be sold without written permission from the API and the US EPA. There are six basic tank designs used for organic liquid storage vessels: fixed roof (vertical and horizontal), external floating roof, domed external (or covered) floating roof, internal floating roof, variable vapor space, and pressure (low and high). Loss mechanisms associated with each type of tank are provided in Section 7.1.2 of AP-42. A vertical fixed-roof tank consists of a cylindrical steel shell with a permanently affixed roof, which may vary in design from cone- or dome-shaped to flat. Losses from fixed-roof tanks are caused by changes in temperature, pressure, and liquid level. Fixed-roof tanks are either freely vented or equipped with a pressure/vacuum vent. The latter allows the tanks to operate at a slight internal pressure or vacuum to prevent the release of vapors during small changes in temperature, pressure, or liquid level. The fixed-roof tank is the least expensive to construct and is generally considered the minimum acceptable equipment for storing organic liquids. Horizontal fixed-roof tanks are constructed for both above-ground and underground service and are usually constructed of steel, steel with a fiberglass overlay, or fiberglass-reinforced polyester. Horizontal tanks are generally small storage tanks with capacities of less than 40,000 gallons. Horizontal tanks are constructed such that the length of the tank is not greater than six times the diameter to ensure structural integrity. Horizontal tanks are usually equipped with pressure/vacuum vents, gauge hatches and sample wells, and manholes to provide access to these tanks. In addition, underground tanks must be cathodically protected to prevent corrosion of the tank shell. The potential emission sources for above-ground horizontal tanks are the same as those for vertical fixed-roof tanks. Emissions from underground storage tanks are associated with changes in the liquid level in the tank. Losses due to changes in temperature or barometric pressure are minimal for underground tanks because the surrounding earth limits the diurnal temperature change, and changes in the barometric pressure result in only small losses. An external floating-roof tank (EFRT) consists of an open-topped cylindrical steel shell equipped with a roof that floats on the surface of the stored liquid. The floating roof consists of a deck, fittings, and rim seal system. Floating decks are constructed of welded steel plate and are of two general types: pontoon or double-deck. With all types of external floating-roof tanks, the roof rises and falls with the liquid level in the tank. External floating decks are equipped with a rim seal system, which is attached to the deck perimeter and contacts the tank wall. The purpose of the floating-roof and rim-seal system is to reduce evaporative loss of the stored liquid. Some annular space remains between the seal system and the tank wall. The seal system slides against the tank wall as the roof is raised and lowered. The floating deck is also equipped with fittings that

Air pollution from wood treatment

111

penetrate the deck and serve operational functions. The external floating-roof design is such that evaporative losses from the stored liquid are limited to losses from the rim-seal system and deck fittings (standing storage loss) and any exposed liquid on the tank walls (withdrawal loss). An internal floating-roof tank (IFRT) has both a permanent fixed roof and a floating roof inside. There are two basic types of IFRTs: tanks in which the fixed roof is supported by vertical columns within the tank, and tanks with a selfsupporting fixed roof and no internal support columns. Fixed-roof tanks that have been retrofitted to use a floating roof are typically of the first type. EFRTs that have been converted to IFRTs typically have a self-supporting roof. Newly constructed IFRTs may be of either type. The deck in IFRTs rises and falls with the liquid level and either floats directly on the liquid surface (contact deck) or rests on pontoons several inches above the liquid surface (noncontact deck). The majority of aluminum internal-floating roofs currently in service have noncontact decks. A floating roof minimizes evaporative losses of the stored liquid. Both contact and noncontact decks incorporate rim seals and deck fittings for the same purposes previously described for external floating roof tanks. Evaporative losses from floating roofs may come from deck fittings, nonwelded deck seams, and the annular space between the deck and tank wall. In addition, these tanks are freely vented by circulation vents at the top of the fixed roof. The vents minimize the possibility of organic vapor accumulation in the tank vapor space in concentrations approaching the flammable range. Domed external (or covered) floating roof tanks have the heavier type of deck used in EFRTs as well as a fixed roof at the top of the shell like IFRTs. Domed EFRTs usually result from retrofitting an EFRT with a fixed roof. This type of tank is very similar to an IFRT with a welded deck and a self-supporting fixed roof. AP-42 notes that as with IFRTs, the function of the fixed roof is not to act as a vapor barrier, but to block the wind. Like IFRTs, these tanks are freely vented by circulation vents at the top of the fixed roof. The deck fittings and rim seals, however, are identical to those on EFRTs. In the event that the floating deck is replaced with the lighter IFRT-type deck, the tank would then be considered an IFRT. Variable vapor space tanks are equipped with expandable vapor reservoirs to accommodate vapor volume fluctuations attributable to temperature and barometric pressure changes. The two most common types of variable vapor space tanks are lifter roof tanks and flexible diaphragm tanks. Lifter roof tanks have a telescoping roof that fits loosely around the outside of the main tank wall. The space between the roof and the wall is closed by either a wet seal, which is a trough filled with liquid, or a dry seal, which uses a flexible coated fabric. Flexible diaphragm tanks use flexible membranes to provide expandable volume. They may be either separate gasholder units or integral units mounted atop fixed-roof tanks. Variable vapor space tank losses occur during tank filling when vapor is displaced by liquid. Loss of vapor occurs only when a tank’s vapor storage capacity is exceeded.

112

Handbook of Pollution Prevention and Cleaner Production

Two classes of pressure tanks are in general use: low pressure (2.5–15 psig) and high pressure (higher than 15 psig). Pressure tanks generally are used for storing organic liquids and gases with high vapor pressures and are found in many sizes and shapes, depending on the operating pressure of the tank. Pressure tanks are equipped with a pressure/vacuum vent that is set to prevent venting loss from boiling and breathing loss from daily temperature or barometric pressure changes. High-pressure storage tanks can be operated so that virtually no evaporative or working losses occur. In low-pressure tanks, working losses can occur with atmospheric venting of the tank during filling operations. No correlations are available to estimate vapor losses from pressure tanks. Emissions from storage occur because of evaporative loss of the liquid during product storage and as a result of changes in the liquid level. The emission sources vary with tank design, as does the relative contribution of each type of emission source. Emissions from fixed-roof tanks are a result of evaporative losses during storage (known as breathing losses or standing storage losses) and evaporative losses during filling and emptying operations (known as working losses). EFRTs and IFRTs are emission sources because of evaporative losses that occur during standing storage and withdrawal of liquid from the tank. Standing storage losses are a result of evaporative losses through rim seals, deck fittings, and/or deck seams. The two significant types of emissions from fixed-roof tanks are storage and working losses. Storage loss is the expulsion of vapor from a tank through vapor expansion and contraction, which are the results of changes in temperature and barometric pressure. This loss occurs without any liquid level change in the tank. The combined loss from filling and emptying is called working loss. Evaporation during filling operations is a result of an increase in the liquid level in the tank. As the liquid level increases, the pressure inside the tank exceeds the relief pressure and vapors are expelled from the tank. Evaporative loss during emptying occurs when air drawn into the tank during liquid removal becomes saturated with vapor and expands, thus exceeding the capacity of the vapor space. Fixed-roof tank emissions vary as a function of vessel capacity, vapor pressure of the stored liquid, utilization rate of the tank, and atmospheric conditions at the tank location. Several methods are used to control emissions from fixed-roof tanks. Emissions from fixed-roof tanks can be controlled by installing an internal floating roof and seals to minimize evaporation of the product being stored. The control efficiency of this method ranges from 60% to 99%, depending on the type of roof and seals installed and on the type of organic liquid stored. Vapor balancing is another means of emission control. Vapor balancing is most common in the filling of tanks at gasoline stations. As the storage tank is filled, the vapors expelled from the storage tank are directed to the emptying gasoline tanker truck. The truck then transports the vapors to a centralized station, where a vapor recovery or control system is used to control emissions. Vapor balancing can have control efficiencies as high as 90–98% if the vapors

Air pollution from wood treatment

113

are subjected to vapor recovery or control. If the truck vents the vapor to the atmosphere instead of to a recovery or control system, no control is achieved. Vapor recovery systems collect emissions from storage vessels and convert them to liquid product. Several vapor recovery procedures may be used, including vapor/liquid absorption, vapor compression, vapor cooling, vapor/ solid adsorption, or a combination of these. The overall control efficiencies of vapor recovery systems are as high as 90–98%, depending on the methods used, the design of the unit, the composition of vapors recovered, and the mechanical condition of the system. In a thermal oxidation system, the air/vapor mixture is injected through a burner manifold into the combustion area of an incinerator. Control efficiencies for this system can range from 96% to 99%. Total emissions from floating-roof tanks are the sum of withdrawal losses and standing storage losses. Withdrawal losses occur as the liquid level, and thus the floating roof, is lowered. Some liquid remains on the inner tank wall surface and evaporates. For an IFRT that has a column-supported fixed roof, some liquid also clings to the columns and evaporates. Evaporative loss occurs until the tank is filled and the exposed surfaces are again covered. Standing storage losses from floating-roof tanks include rim-seal and deck-fitting losses, and for IFRTs also include deck-seam losses for constructions other than welded decks. Other potential standing storage loss mechanisms include breathing losses as a result of temperature and pressure changes. Rim-seal losses can occur through many complex mechanisms, but for EFRTs the majority of rim-seal vapor losses have been found to be wind induced. No dominant wind loss mechanism has been identified for internal floating-roof or domed external floating-roof tank rim-seal losses. Losses can also occur due to permeation of the rim-seal material by the vapor or via a wicking effect of the liquid, but permeation of the rim-seal material generally does not occur if the correct seal fabric is used. Testing has indicated that breathing, solubility, and wicking loss mechanisms are small in comparison to the wind-induced loss. The rim-seal factors presented in this section incorporate all types of losses. The rim-seal system is used to allow the floating roof to rise and fall within the tank as the liquid level changes. The rim-seal system also helps to fill the annular space between the rim and the tank shell, and therefore minimizes evaporative losses from this area. A rim-seal system may consist of just a primary seal or a primary and a secondary seal, which is mounted above the primary seal. The primary seal serves as a vapor conservation device by closing the annular space between the edge of the floating deck and the tank wall. Three basic types of primary seal are used on external floating roofs: mechanical (metallic) shoe, resilient filled (nonmetallic), and flexible wiper seals. Some primary seals on EFRTs are protected by a weather shield. Weather shields may be of metallic, elastomeric, or composite construction and provide the primary seal with longer life by protecting the primary seal fabric from deterioration due to exposure to weather, debris, and sunlight. A secondary seal may be used to provide some

114

Handbook of Pollution Prevention and Cleaner Production

additional evaporative loss control over that achieved by the primary seal. Secondary seals can be either flexible wiper seals or resilient-filled seals. The reader may refer to Section 7.1.3 of AP-42 for emission estimation procedures. These procedures are valid for all petroleum liquids, pure volatile organic liquids, and chemical mixtures with similar true vapor pressures. It is important to note that in all the emission estimation procedures the physical properties of the vapor do not include the noncondensables (e.g. air) in the gas but only refer to the condensable components of the stored liquid. The emission estimation procedures have been used as the basis for the development of a software program to estimate emissions from storage tanks. The software program entitled ‘‘TANKS’’ is available via the EPA’s website at www.epa.gov/ttn/chief/software/tanks/.

4.3.7

Fugitive emissions from spills

Common practice in the industry has been to stockpile liquid wastes in unlined surface impoundments. This practice was eliminated in the mid to late 1980s through enforcement of the Resource Conservation and Recovery Act (RCRA). Unfortunately, the practice was used so widely for many decades, with impoundments that covered land areas exceeding an acre or more at some facilities, that groundwater was significantly impacted at certain sites, which continue to require aggressive treatment through current times. At the time of operation of these impoundments, significant air emissions occurred. Emissions largely included PAHs and VOCs. The strength of these historical air emissions largely depended on the size of the ponds and compositions of the waste streams. Ponds that largely contained sap water and occasional blowdown from cylinder vent condensates would have been less severely affected than facilities that attempted to rely on large area impoundments as recovery systems, albeit poor for coal-tar creosotes and oil. While this practice has been eliminated, spills continue to occur at facilities. Spill contingency and prevention plans have been devised to minimize these events at facilities, but their effectiveness depends almost entirely on a facility committed to minimizing these events with aggressive monitoring and education of workers. To calculate the emissions resulting from sizeable spills, the EPA’s calculation procedure from ‘‘Risk Management Guidance for Offsite Consequence Analysis’’ (US EPA Publication EPA-550-B-99-009, April 1999) can be consulted. This publication provides the following recommended formula for calculating the fugitive emissions from a pool of liquid: E ¼ ð0:1268APM0:667 u0:78 Þ=T;

(4.4)

where E ¼ evaporation rate of the liquid (kg/min), u ¼ wind speed just above the pool liquid surface (m/s), M ¼ pool liquid molecular weight, A ¼ pool surface area (m2), P ¼ vapor pressure of the pool liquid at the pool temperature (kPa),

Air pollution from wood treatment

115

and T ¼ pool liquid ambient temperature ( K; assumed to be the same as ambient conditions).

4.3.8

Fugitive dust emissions

Older facilities that have been in operation for many years, especially those predating the RCRA rules, are likely to have soil on the property that is contaminated from historical spills and poor housekeeping practices. Vehicular traffic over plant roads and through stockyards creates dust that becomes airborne. AP-42 Section 13.2.3 (November 2006) can be consulted to calculate the amount of fugitive dust emissions. AP-42 provides the following equation to calculate the mass of particulate emissions from the suspension of loose material on road surfaces within the plant: E ¼ kðSL =2Þ0:65  ðW=3Þ1:5  C;

(4.5)

where E ¼ particulate emission factor, k ¼particle size multiplier (from Table 13.2.1-1, AP-42; sample values reported in the table are 1.1 g/vehicle mile traveled (VMT) for PM2.5 and 7.3 g/VMT for PM10), sL ¼ road surface silt loading (g/m2; for sL Table 13.2.1-4 reports silt contents for paved roads at industrial facilities), W ¼ average weight of vehicles, C ¼ emission factor for 1980s vehicle fleet exhaust, brake wear, and tire wear (from Table 13.2.1-2, C ¼ 0.1005 g/vehicle kilometer traveled (VKT) for PM2.5 and 0.1317 g/VKT for PM10).

4.4 Wood-waste burning 4.4.1

Waste sources and types

Wood-treating plants generate significant amounts of waste wood in the form of bark, sawdust, wood chips, and trimmings. Provided this scrap does not come into contact with treatment chemicals, it is a good source of biomass fuel that can be used to generate electricity and steam. When mixed with treated wood and/or process sludge, both special engineering and operational practices are needed to ensure an ultra-high degree of combustion efficiency in order to prevent the formation of dioxins, furans, and PAHs. Given the typically low moisture (10%), sulfur (<0.3%), nitrogen (<0.4%), and ash (<2%) contents, as well as a high heating value (>21 kJ/g) and bulk density compared to other biomass fuels, many treated woods, such as telephone poles, transmission poles and railroad ties, are a potentially attractive renewable fuel for co-firing in industrial wood-waste boilers. Such treated woods are available in large quantities and often have very high landfill disposal costs (up to $80/ton) to utilities and other industries. Process sludge, on the other hand, is not a good source of renewable fuel for co-firing. These wastes contain many inert materials that lower combustion efficiency, and toxic metals, and often

116

Handbook of Pollution Prevention and Cleaner Production

have a high moisture content, which further lowers combustion efficiency. Up until the early 1990s with the introduction of the boiler industrial furnace (BIF) rules, many wood-treating facilities indiscriminately co-fired wood-waste boilers with this type of waste without any regard for the pollution generated. Today there is ongoing concern that wood-treating facilities that do continue to burn treated wood wastes generate significant pollution. The possibilities for treated wood recycling are limited, because the treating chemicals can easily diffuse in undesirable areas like the interiors of buildings, or in soil and groundwater. The production of particleboard from treated wood is also questionable due to the same concerns. Similar reasons inhibit the use of treated wood residues in landspreading. Here, the danger of biocide release by uncontrolled leaching needs to be considered. Combustion of either treated wood or process sludge results in the formation of both fly and bottom ashes that will contain not only dioxins, furans, and PAHs, but heavy metals as well. The term fly ash refers to the lighter particulate matter that is emitted from the stack of the boiler, whereas bottom ash is the heavier particulate matter that settles out on to the grate of the furnace. Fly ash can be controlled using mechanical types of air pollution controls such as multiclones, wet scrubbers, electrostatic precipitators, or fabric filters (called baghouses). The ash itself may be considered toxic as it will contain heavy metals. Creosote coal tars are derived from coal, which contains a wide range of metals including arsenic, cadmium, chrome, and lead. These tend to partition during combustion, concentrating in the bottom ash of the boiler. As such the ash must be managed responsibly either in secure landfills or by vitrification methods. Combustion is a complex series of chemical reactions, but from a physical standpoint may be described as the rapid combination of oxygen with a fuel, such as natural gas or wood, resulting in the release of heat. Most fuels contain carbon and hydrogen, and the oxygen usually comes from air. Combustion generally consists of the following overall reactions: Carbon þ Oxygen/Carbon dioxide þ Heat Hydrogen þ Oxygen/Water vapor þ Heat: Stoichiometric or perfect combustion is obtained by mixing and burning exactly the correct proportions of fuel and oxygen so that no oxygen remains at the end of the reaction. If too much oxygen is supplied, the mixture is lean and the reaction is oxidizing. This results in a flame that is relatively shorter. If too much fuel is supplied, the mixture is rich and the reaction is reducing. This typically results in a flame that is relatively longer and sometimes smoky. In terms of chemistry, combustion is a chemical reaction in which an oxidant reacts rapidly with a fuel to liberate stored energy as thermal energy, most often in the form of high-temperature gases. Small amounts of electromagnetic energy (light), electric energy (free ions and electrons), and mechanical energy (noise) are also produced during the combustion process.

Air pollution from wood treatment

117

Conventional hydrocarbon fuels contain primarily hydrogen and carbon, in elemental form or in various compounds. Their complete combustion produces carbon dioxide (CO2) and water (H2O); however, small quantities of carbon monoxide (CO) and partially reacted flue gas constituents (gases and liquid or solid aerosols) also form. Most conventional fuels also contain small amounts of sulfur, which is oxidized to sulfur dioxide (SO2) or sulfur trioxide (SO3) during combustion, and noncombustible substances such as mineral matter (ash), water, and inert gases. Flue gas is the product of complete or incomplete combustion and includes excess air (if present), but not dilution air. Fuel combustion rate depends on three factors:   

the rate of the chemical reaction of the combustible fuel constituents with oxygen; the rate at which oxygen is supplied to the fuel (the mixing of air and fuel); and the temperature in the combustion zone.

The reaction rate is fixed by fuel selection. Increasing the mixing rate or temperature increases the rate of combustion. When engineers refer to complete combustion of hydrocarbon fuels, they infer that all hydrogen and carbon in the fuel is oxidized to form H2O and CO2. Generally, for complete combustion to be accomplished excess oxygen or excess air must be supplied beyond the amount theoretically required to oxidize the fuel. Excess air is usually expressed as a percentage of the air required to completely oxidize the fuel. In stoichiometric combustion of a hydrocarbon fuel, the fuel is reacted with the exact amount of oxygen required to oxidize all carbon, hydrogen, and sulfur in the fuel to CO2, H2O, and SO2. Therefore, exhaust gas from stoichiometric combustion theoretically contains no incompletely oxidized fuel constituents and no unreacted oxygen (i.e. no CO and no excess air or oxygen). The percentage of CO2 contained in products of stoichiometric combustion is the maximum attainable and is referred to as the stoichiometric CO2, ultimate CO2, or maximum theoretical percentage of CO2. Stoichiometric combustion is seldom if ever realized in practice in simple or conventional combustion equipment because of imperfect mixing and finite chemical reaction rates. For economy and safety, most combustion equipment is designed to operate with some excess air. The purpose of this is to ensure that fuel is not wasted and that combustion is complete despite variations in fuel properties and in the supply rates of fuel and air. The amount of excess air to be supplied to any combustion equipment depends on four primary factors: 1. 2. 3. 4.

the expected variations in fuel properties and in fuel and air supply rates; the equipment application; the degree of operator supervision required or available; the control requirements for the machine used to burn fuel.

As a general rule, in order to achieve maximum efficiency, combustion at low excess air is desirable.

118

Handbook of Pollution Prevention and Cleaner Production

The term incomplete combustion refers to a condition when a fuel element is not completely oxidized during combustion. For example, a hydrocarbon may not completely oxidize to carbon dioxide and water, but may form partially oxidized compounds, such as carbon monoxide, aldehydes, and ketones. Conditions that promote incomplete combustion include such factors as: 1. insufficient air and fuel mixing (causing local fuel-rich and fuel-lean zones); 2. insufficient air supply to the flame (providing less than the required quantity of oxygen); 3. insufficient reactant residence time in the flame (preventing completion of combustion reactions); 4. flame impingement on a cold surface (quenching combustion reactions); 5. flame temperature that is too low (slowing combustion reactions).

When incomplete combustion occurs the combustion process uses fuel inefficiently, and it can be hazardous because carbon monoxide and various products of incomplete combustion are generated as air pollution. For chemical engineers in particular, combustion is a challenging subject because the combustion reactions are complex. The reaction of oxygen with the combustible elements and compounds in fuels occurs according to fixed chemical principles, including:     

chemical reaction equations; law of matter conservation – the mass of each element in the reaction products must equal the mass of that element in the reactants; law of combining masses – chemical compounds are formed by elements combining in fixed mass relationships; chemical reaction rates; oxygen availability – oxygen for combustion is normally obtained from air, which is a physical mixture of nitrogen, oxygen, small amounts of water vapor, carbon dioxide, and inert gases.

For practical combustion calculations (i.e. within everyday engineering accuracy), dry air consists of 20.95% oxygen and 79.05% inert gases (nitrogen, argon, and so forth) by volume, or 23.15% oxygen and 76.85% inert gases by mass. For calculation purposes, nitrogen is assumed to pass through the combustion process unchanged (although small quantities of nitrogen oxides form and, in the case of incomplete combustion, nitrated PAHs are formed). Other important factors in combustion are:   

flammability limits; ignition temperature; heating value.

Fuel burns in a self-sustained reaction only when the volume percentages of fuel and air in a mixture at standard temperature and pressure are within the upper and lower flammability limits or explosive limits (UEL and LEL). Both temperature and pressure affect these limits. As the temperature of the mixture increases, the upper limit increases and the lower limit decreases. As the pressure

Air pollution from wood treatment

119

of the mixture decreases below atmospheric pressure, the upper limit decreases and the lower limit increases. This is a well-understood principle and one that has been experimentally determined by many investigators and reported by the National Fire Protection Association (NFPA) as well. The term ignition temperature refers to the lowest temperature at which heat is generated by combustion faster than heat is lost to the surroundings and combustion becomes self-propagating. Table 4.11 provides some typical values for the ignition temperatures of common materials. The fuel–air mixture will not burn freely and continuously below the ignition temperature of a material unless heat is supplied, but chemical reaction between the fuel and air may occur. Ignition temperature is affected by a large number of factors. Combustion produces thermal energy or heat. The quantity of heat generated by complete combustion of a unit of specific fuel is constant and is termed the heating value, heat of combustion, or caloric value of that fuel (Table 4.12). The heating value of a fuel can be determined by measuring the heat evolved during combustion of a known quantity of the fuel in a calorimeter, or it can be estimated from chemical analysis of the fuel and the heating values of the various chemical elements in the fuel. Higher heating value, gross heating value, or total heating value are terms that include the latent heat of vaporization and is determined when water vapor in the fuel combustion products is condensed. Conversely, lower heating value or net heating value is obtained when the latent heat of vaporization is not included. When the heating value of a fuel is specified without designating higher or lower, it generally means the higher heating value in the USA. (The term lower heating value is mainly used for internal combustion engine fuels.) Heating values are usually expressed in Btu/ft3 for gaseous fuels, Btu/gal for liquid fuels, and Btu/lb for solid fuels. Heating values are always given in relation to a certain reference temperature and pressure, usually 60, 68, or 77 F and 14.696 psia, depending on the particular industry practice.

Table 4.11 Typical ignition temperatures of common fuels in fuel–air mixtures Substance

Temperature (8F)

Activated coke Carbon monoxide Hydrogen Methane Propane n-Butane Ethylene Acetylene Sulfur Hydrogen sulfide

1220 1128 968 1301 871 761 914 763–824 374 558

120

Handbook of Pollution Prevention and Cleaner Production

Table 4.12 Typical heating values of materials found in common fuels Substance

Higher heating value (Btu/lb)a

Specific volume (ft3/lb)b

Carbon (to CO) Carbon (to CO2) Carbon monoxide Hydrogen Methane Ethane Propane Butane Acetylene Sulfur (to SO2) Sulfur (to SO3) Hydrogen sulfide

3950 14,093 4347 61,095 23,875 22,323 21,669 21,321 21,502 3980 5940 6537

– – 13.5 188 23.6 12.5 8.36 6.32 14.3 – – 11

a

Values standardized to 60 F, 30 inHg, dry. For gases saturated with water vapor at 60 F, deduct 1.74% of the value to adjust for gas volume displaced by water vapor. b Values reported at 32 F and 29.92 inHg.

With incomplete combustion, not all fuel is completely oxidized and the heat produced is less than the heating value of the fuel. Therefore, the quantity of heat produced per unit of fuel consumed decreases, implying lower combustion efficiency. Not all heat produced during combustion can be used effectively. The greatest heat loss is the thermal energy of the increased temperature of hot exhaust gases above the temperature of incoming air and fuel. Other heat losses include radiation and convection heat transfer from the outer walls of combustion equipment to the environment. Now let’s focus on the burning of wood. The combustion of wood has three requirements: fuel, air, and heat. If any one of these is removed, burning ceases. When all three are available in the correct proportion, combustion is selfsustaining because the wood itself releases more than enough heat to initiate further burning. The rate at which wood burns is controlled by the amount of air. A lack of air causes wood to smolder and produce pollutants. Too much air will cool the fire and waste heat. Another very important aspect of combustion is the energy content of the wood fuel, i.e. the Btu (British thermal units) content. Energy content is greatly affected by the moisture content and weight of the wood. For example, hardwood and softwood at 50% moisture will contain about 4700 Btu per pound. The same wood at 20% moisture will contain about 6200 Btu per pound. Hardwood has about twice the weight as softwood and twice the heat content. The same is true with wood chips – 4000 Btu per pound green (50% moisture content) and 7400 Btu per pound dry (10% moisture content).

Air pollution from wood treatment

121

Taking these factors into consideration, let’s examine the stages of wood burning. Wood combustion may be simply described as undergoing three distinct stages of burning, where all three stages occur simultaneously:  



Stage 1. The wood is heated to evaporate and drive off moisture. Stage 2. Starting at about 500 F (260 C) wood begins to break down chemically and volatile matter is vaporized. The vapors contain 50–60% of the heat value of the wood. These vapors have to be heated to 1100 F (593 C) at a minimum in order to burn. If not, smoke is generated that can coat heat exchange surfaces and chimneys with creosote, and produce harmful PAHs and dioxins. Stage 3. Once the volatile gases are released, the remaining material (charcoal) burns at temperatures above 1500 F (815 C).

The process described is idealized, but it gives us a simplified working framework to better characterize the nature of wood combustion. A final term we introduce is that of destruction and removal efficiency (DRE), which is most appropriately related to incineration. Incineration is different from normal combustion in the sense that the objective is to completely consume fuel or rather any toxins contained in the fuel or harmful products produced as a result of the combustion process. This term is important because some woodtreating facilities operate wood-waste boilers for the purpose of generating steam and chemicals can enter the feed to boilers that are used for this purpose. A primary measure of incineration performance is the characteristic known as DRE for polyorganic hydrocarbons (POHCs). DRE is an explicit RCRA performance standard that requires the achievement of 99.99% DRE performance (‘‘four nines’’) for non-polychlorinated biphenyl (PCB) and nondioxin waste. Dioxin-containing or dioxin-forming wastes require incineration facilities that are capable of achieving 99.9999% DRE (‘‘six nines’’). When chemicals such as creosote or PCP are introduced into the fuel by means of chemical spills, process sludge from treating cylinders, or treated wood scrap, PAHs, dioxins, dibenzofurans, and other hazardous air pollutants can be generated. These pollutants need to be controlled through appropriate combustion controls, by retrofitting the combustion equipment with air pollution controls, by preventing chemicals from entering the fuel feed, and through continuous emissions monitoring. Incineration under controlled conditions is considered the most appropriate destruction method for treated wood wastes. Oehme and Zuller (1995) and Chagger et al. (1998) have noted that the advantages of incineration include:  

 

volume reduction; lower net CO2 emissions (the carbon dioxide released during combustion of biomass equals that taken up during growth; full or partial replacement of fossil fuels with wood or biomass would therefore reduce net emissions of CO2); the possibility of substituting other fuel types for energy production (because of the good calorific value and low sulfur content); the removal of residues of environmental concern.

122

Handbook of Pollution Prevention and Cleaner Production

As noted, it is well known that polychlorodibenzodioxins and polychlorodibenzofurans are always formed during wood combustion via precursors like phenols and lignin or via de novo reactions in the presence of particulate carbon and chlorine. When waste wood is burnt, the levels of dioxins and furans in the flue gas emissions are significantly lower than those obtained from other sources. Even nontreated wood contains small amounts of chlorine, which means that dioxin emissions can only be minimized, but not eliminated (Salthammer et al., 1995). According to new EC regulations regarding the classification of biomass and of waste combustion systems, many biomass residues (e.g. nondangerous wood residues) will be subject to severe dioxin emission regulations, because a perfect separation of ‘‘clean’’ wood and ‘‘nonclean’’ varieties (i.e. from demolition, containing laminates or particleboard) is often impossible at the post-consumer level. This compromises a large part of the potential use of biomass combustors, in particular in small-scale applications. The severity of pollution depends on both the composition and concentration of the waste streams that are co-fired and the combustion dynamics, which are limited by the boiler design and the types of pollution controls employed. Here we make an important distinction in that wood-waste boilers typically used by the industry are classical combustion systems that differ from incinerators. The role of combustion equipment is to burn a relatively clean fuel in an efficient manner for the purpose of generating steam and electricity. It is a practice that aims to convert waste to energy. Incineration has a very different objective. The objective of incineration is to apply energy to efficiently and completely destroy certain chemicals of concern. Incineration does not or should not concern itself with how efficiently a waste is converted into a useful energy form, but rather its objective is to supply as much energy as possible in order to destroy chemical toxins. Historical practice by the industry sector shows that it has generally not bothered to make this distinction, but rather has abused legitimate waste to energy projects by attempting to incinerate wastes such as sludge, arguing these sources to be fuel supplements. A primary measure of incineration performance is the characteristic known as DRE for POHCs. This explicit RCRA performance standard requires the achievement of 99.99% DRE performance (‘‘four nines’’) for non-PCB and nondioxin waste. Dioxin-containing or dioxin-forming wastes require incineration facilities that are capable of achieving 99.9999% DRE (‘‘six nines’’). Unless the six nines of destruction can be demonstrated though stack testing, an industrial wood-waste boiler cannot be considered an appropriate device for burning treated wood or process sludge. There is considerable controversy in the literature on reported emission factors for treated wood-waste burning. We believe that only emission factors based on stack testing measurements followed by continuous emissions monitoring (CEM) should be employed to ensure that pollution emissions do not pose harm to communities. The foregoing discussion summarizes emission factors reported in the literature. While we have relied on such data in ascertaining historical impacts on communities, uncertainties in the application of these

Air pollution from wood treatment

123

factors only permit ranges of probable emissions to be calculated to within scientific certainty. In this day and age, where stack testing and monitoring instrumentation are sophisticated and precise, it is irresponsible not to employ such tools to accurately quantify, report, and control stack emissions.

4.4.2

Dioxins and furans

A dioxin is a compound that contains the dibenzo-p-dioxin nucleus, and a furan is a compound that contains the dibenzofuran nucleus. The term isomer refers to compounds with the same empirical formula. The term homolog refers to compounds within the same series (e.g. chlorodibenzo-p-dioxin (CDD) or chlorodibenzofuran (CDF)), but with a different number of chlorine atoms (tetra-CDD, penta-CDF, etc.). The tetrachlorinated derivatives 2,3,7,8-TCDD and 2,3,7,8-TCDF represent the most toxic compounds of their respective families. CDDs and CDFs have no known technical use and are not intentionally produced. They are formed as unwanted by-products of certain chemical processes during the manufacture of chlorinated intermediates and in the combustion of chlorinated materials. The toxicity equivalency factor (TEF) method is an interim procedure for assessing the risks associated with exposures to complex mixtures of CDDs/ CDFs. This method relates the toxicity of the 210 structurally related pollutants (135 CDFs and 75 CDDs), and the toxicity of the most highly studied dibenzop-dioxin, 2,3,7,8-TCDD. The TEF method is used as a reference when analyzing the toxicity of the other 209 compounds (i.e. in terms of equivalent amounts of 2,3,7,8-TCDD). This approach simplifies risk assessments, including assessments of exposure to mixtures of CDDs and CDFs such as incinerator fly ash, hazardous wastes, contaminated soils, and biological media. In 1989 an international effort adopted a common set of TEFs. This set of TEFs was agreed upon and implemented. It is called the International TEFs/89 (I-TEFs/89). Toxicity estimates, expressed in terms of toxic equivalents (TEQs), or equivalent amounts of 2,3,7,8-TCDD, are generated by using the TEF to convert the concentration of a given CDD/CDF into an equivalent concentration of 2,3,7,8-TCDD. The I-TEQs/89 are obtained by applying the I-TEFs/89 to the congener-specific data and summing the results. CDDs are white solids. The most toxic and most extensively studied of the CDDs is 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD). This compound is extremely lipophilic, exhibiting a high degree of solubility in fats, oils, and relatively nonpolar solvents. 2,3,7,8-TCDD is only sparingly soluble in water. Most CDDs are rather stable toward heat, acids, and alkalis, although heat treatment with an alkali (under conditions similar to alkaline extraction of tissue) completely destroys octachlorodibenzo-p-dioxin (OCDD). CDDs begin to decompose at about 930 F (500 C), and at about 1470 F (800 C) virtually complete degradation of 2,3,7,8-TCDD occurs within 21 seconds. CDDs are susceptible to photodegradation in the presence of ultraviolet light, and undergo

124

Handbook of Pollution Prevention and Cleaner Production

photoreductive dechlorination in the presence of an effective hydrogen donor (US EPA, 1984). Dibenzofuran is relatively stable toward alkalis and acids. The EPA has reported that the pyrolysis of this compound for 1.4 seconds in nitrogen at 0.6 atm and 1536 F (830 C) caused only 4.5% decomposition, and no decomposition is observed below 1536 F (830 C). The products of decomposition are toluene, styrene, indene, durene, naphthalene, water, hydrogen, carbon, o-ethylphenol, and polyphenyl ether. Alkyl- or halogen-substituted dibenzofurans are expected to be less soluble in water and more soluble in organic solvents than dibenzofuran because these compounds are less polar than dibenzofuran (US EPA, 1983). Dioxins and furans are emitted into the atmosphere from a wide variety of processes such as waste incineration, combustion of solid and liquid fuels in stationary sources for heat and power generation, crematories, iron and steel foundries/scrap metal melting, combustion-aided metal recovery, kraft pulp and paper production/black liquor combustion, internal combustion engines, carbon regeneration, forest fires, organic chemical manufacture and use, and Portland cement manufacture. These same air pollutants may be introduced through domestic activities such as barrel burning of trash, outdoor barbecues, and the use of wood-burning stoves and fireplaces. The concentrations of pollutants and subsequent emission factors can be many times greater than those observed from industrial-size boilers and incinerators; however, the infrequent use of such activities makes them low-level sources of air pollution. Let’s maintain perspective in that an industrial wood-waste boiler at a typical wood-treating plant operates 24/7 and generates several million pounds of air emissions on an annual basis. The contribution to air pollution that may impact neighboring communities is orders of magnitude beyond domestic activities, especially in small communities. Tables 4.13–4.15 have been compiled from the literature. They provide emission factors for different combustion systems. For comparison, Table 4.16 provides emission factors for burning wood waste in stoves and other nonindustrial combustion systems. While the reported emissions vary widely, there are some generalities that can be stated: 1. The greatest dioxin emissions are reported for wood that has been exposed to salts where there are measurable chlorine levels. This is logical since the presence of chlorine will promote dioxin formation. 2. Paper mill boilers generally have the greatest dioxin emissions. There are various reasons for this, explained in later chapters. 3. Process sludge feed systems generate high levels of dioxins. Regardless of the system or pollution controls employed, dioxin emissions are problematic when co-firing is done with this type of feed.

Industrial boilers generate considerably less dioxins than residential or small farm application-type combustion systems. When properly operated

Type of combustor

Flue gas cleaning system

Stick wood boiler (35 kW)

Cyclone

Stick wood boiler (35 kW)

Cyclone

Automatic chip burner (110 kW) under stoker Automatic chip furnace (150 kW) pre-oven grate firing Automatic chip furnace (150 kW) pre-oven grate firing Automatic chip furnace (150 kW) pre-oven grate firing Automatic chip furnace (150 kW) pre-oven grate firing Pilot scale batch type, three-cell incinerator 150 kW prototype pre-oven furnace 150 kW prototype pre-oven furnace

Emission factor (ng I-TEQ/kg dry wood)

0.024

0.23

Natural beech wood sticks Natural beech wood sticks Natural wood chips

0.043

0.41

0.267

2.57

Cyclone

Natural wood chips

0.083a

0.79

Cyclone

Natural wood chips

0.217a

2.08

Ceramic filter

Chipboard chips

0.024

0.29

Ceramic filter

Chipboard chips

0.095

0.91

Wet scrubber

Aspen bark (0.007% Cl)

0.020

Ceramic filter and SCR catalyst

Natural wood

0.083b, 0.836c, 0.052d 0.015 0.016 0.030 0.303 0.498 0.880e

Pine chips Pine chips Cl-free chipboards Pine chips Pine chips Wood chips

Continued

125

Pre-oven furnace (35 kW) Pre-oven furnace (35 kW) Pre-oven furnace (150 kW) Under stoker firing (230 kW) Under stoker firing (230 kW) Moving grate firing (450 kW)

Fuel

Dioxin emission (ng I-TEQ/dscm at 11% O2)

Air pollution from wood treatment

Table 4.13 Dioxin emissions in gases from uncontaminated wood combustion

Type of combustor Moving grate firing (2 MW) Moving grate firing (16 MW) Wood-dust burner (9.6 MW) Wood-dust burner (9.6 MW) 30 kW wood boiler (full load) 30 kW wood boiler (low load) Grate combustion chamaber

a

Cyclone and fabric filter (with active carbon and lime) Electric filter Cyclone; bag filter Cyclone/electric filter Multiclone None None

Fuel

Dioxin emission (ng I-TEQ/dscm at 11% O2)

Bark chips Bark chips Pine chips Pine chips Pieces of beech Pieces of conifers Uncontaminated wood

0.019 0.006 0.004 0.006 0.0025–0.0075 0.00375–0.01 0.156f,g, 0.008g,h

Wood chips Wood chips Wood chips Pine wood (100%) Wood pellets Wood pellets

0.007g,h 0.050g,h 0.039g,h 0.0783g 0.0636 0.0273

Emission factor (ng I-TEQ/kg dry wood)

0.53i 0.21i

Sampling at approximately 350 C, before the ceramic filter. In raw gas. c After filter. d In clean gas. e Furnace has previously been operated with urban waste wood. Before the test run with uncontaminated wood, the furnace and the boiler were thoroughly cleaned and operated for some days with uncontaminated wood. f UF uncontaminated wood (forestry wood chips, log wood or chloride- and heavy metal-free chipboards). g No precise base used to express the data. h SCR, selective catalytic reduction. i ng I-TEQ/kg fuel. Source: Lavric et al. (2004). b

Handbook of Pollution Prevention and Cleaner Production

11 MW heating plant I MW heating plant 0.6 MW heating plant 13.8 MW boiler 19 kW stoker boiler, 100% load 19 kW stoker boiler, 26% load

Flue gas cleaning system

126

Table 4.13 Dioxin emissions in gases from uncontaminated wood combustiondcont’d

Air pollution from wood treatment

127

Table 4.14 Dioxin emissions in gases from waste-wood combustion

Type of combustor Dutch oven boiler

Flue gas cleaning system Cyclone and fabric filter Multi-cyclone

Fuel

Salt-laden wood waste Quad-cell wood-fired Wood waste and boilers sawdust from nonindustrial logging operations Laboratory conditions None PCP-impregnated sawdust, 550 C Laboratory conditions None PCP-impregnated sawdust, 650 C Laboratory conditions None Utility pole Automatic chip furnace None Wood-waste chips (150 kW) – pre-oven from demolition grate firing of buildings Automatic chip furnace Cyclone Wood-waste chips (450 kW) – pre-oven from demolition grate firing of buildings Automatic chip furnace Cyclone and Wood-waste chips (850 kW) – grate firing fabric filter from demolition of buildings Automatic chip furnace Cyclone and ESP Wood-waste chips (1800 kW) – grate firing from demolition of buildings Mill A (power boiler) Scrubber and ESP Salt-laden hog fuel Mill B (power boiler) Scrubber and ESP Salt-laden hog fuel (0.24% and 0.42% Cl) Mill C (power boiler) Scrubber and ESP Salt-laden hog fuel

Emission factor (ng I-TEQ/kg of dry wood) 17.1 0.64

1.26–2.72 0.89–2.635 1.74 170.7

173.3

26.0

92.0

240–270 71

23

Source: Lavric et al. (2004).

with appropriate combustion controls and pollution control equipment, wood-waste boilers constitute a reasonable technology for waste-to-energy programs for treated wood that is metered in relatively small amounts compared to the total feed. Most permits that we have reviewed show this limit to be about 5% (i.e. about 5% of the total wood feed may be treated wood waste). When abused as in the past, where process sludge and treated wood were co-fired relying on poor feed arrangements and combustion control protocols, large-scale pollution problems can occur. While process sludge may also be handled in wood-fired boilers under very carefully controlled combustion conditions, we do not recommend this approach

128

Table 4.15 Dioxins measured in ashes and soot Type of combustor

Ceramic filter and SCR system

Wood Nontreated wood and wood impregnated with inorganic wood preservative (boron, chromium, and copper) Nontreated wood and wood impregnated with inorganic wood preservative (boron, chromium, and copper) Natural wood, good combustion

Ceramic filter and SCR system

Natural wood, good combustion

117

Ceramic filter and SCR system

Waste wood, good combustion

22.3

Two-stage furnace

0.07

0.66 21.2

215 52.1

0.04

38.8

89.6

372

Handbook of Pollution Prevention and Cleaner Production

Fuel

Two-stage furnace Two-stage furnace

Prototype 150 kW boiler (moving grate with precombustion zone) Prototype 150 kW boiler (moving grate with precombustion zone) Prototype 150 kW boiler (moving grate with precombustion zone)

Furnace ash Bottom ash Fly ash (ng I-TEQ/kg) (ng I-TEQ/kg) (ng I-TEQ/kg)

PM controls

Mill A (power boiler) Mill B (power boiler) Mill D (power boiler – Dutch oven-type furnace) Fixed bed, batch operated small-scale incinerator Kiln

Cyclone and injection system for potassium hydroxide Scrubber and ESP Scrubber and ESP

3133

722

Multiclone and ESP

Salt-laden hog fuel Salt-laden hog fuel (0.24% and 0.42% Cl) Hog (bark) fuel (0.69% Cl)

Cyclone

Paper and wood

48

24

Bag filter or ESP

Wood chips (demolition waste) Sludge Sludge Medical wastes plus wood chips (demolition waste) Wood chips (demolition waste) Spruce wood

310

6700

390 37 61

3300 89 48,000

97

1200

23

5

Kiln Kiln Stoker Stationary-floor fluidized bed 50 kW automatically charged multi-fuel furnace for domestic applications

Waste wood, good combustion

None

4300–5400 2000–2100 8000

61

Air pollution from wood treatment

850 kW heating system (moving grate, primary and secondary air)

Source: Lavric et al. (2004).

129

130

Handbook of Pollution Prevention and Cleaner Production

Table 4.16 Dioxin emissions from non-industrial combustion systems Combustion system Gaseous emissions Household stoves, open (6 kW) Household stoves, closed (6 kW) Batchwise operated masonry heater Conventional wood stove Conventional wood stove Noncatalytic, advanced technology wood stove 6.3 MW district heating 5 kW stove, normal operation 5 kW stove, reduced combustion Household stoves, closed (6 kW) Household stoves, closed (6 kW)

Municipally owned incinerator with cyclone 5 kW stove, normal operation 5 kW stove, reduced combustion

Fuel

Emission factor (ng I-TEQ/kg dry wood)

Natural beech wood sticks

0.077

Natural beech wood sticks

1.25

Untreated beech logs with small share of bark Maple Spruce Maple

0.626 0.270–0.330 0.200–0.240 0.850–1.010

Wood chips Birch, air-dried firewood

0.026 5.1

Birch, air-dried firewood

0.61

Charcoal used for grilling meat Household waste consisting of 2⁄3 paper and 1⁄3 plastic

0.04

Tree, leaves

4.6

Birch, kiln-dried furniture wood Birch, kiln-dried furniture wood

1.9

Furnace ash/bottom ash/fly ash Smoke house Wood 6 kW fireplace Charcoal used wood stove for grilling meat Stove Natural wood Stove Beech, log with 2.5% plastic Stove Beech, log with 30% packing material Stove Painted wood Stove Beech, log with 5% PVC Open-air incineration Wood scrap of broken buildings and houses Fire site Houses and buildings a

ND, no data.

3230

0.64

NDa/ND/0.03 0.55/ND/ND ND/32/ND ND/12-17/ND ND/594-1334/ND ND/380-553/ND 2240/ND/ND ND/63.2-2080/ND

ND/442/ND

Air pollution from wood treatment

131

because we have found too many examples where systems fail and high levels of dioxins were suspected. The wide range of emission factors presented in Tables 4.11–4.13 clearly show that combustion conditions as well as the type of combustion system employed determine how polluting stack emissions can be. Poorly designed and operated systems will generate as much dioxin and PAH emissions as fireplaces, barrel burning, and small-scale non-industrial incinerators. Another concern is that commercial systems that have been permitted for co-firing of wastes have achieved operating status by demonstrating that they are capable of achieving 99.999% DRE under an ideal set of operating conditions. We found no examples where startup or transient operational conditions resulting in stack opacity excesses caused a facility to report these emissions on a mass basis. Unless facilities monitor and control these situations, the frequency of such events may produce excessive levels of stack emissions. For this and other reasons explained earlier, we believe that CEM is critical to the operation of wood-fired boilers and that automated controls that shut off the feed of alternative waste fuels should be an integral part of the system design. Little attention has been given to gasification. In contrast to conventional wood-fired boilers, these systems operate at higher temperatures and are much more versatile in achieving high DREs of both dioxins and PAHs, and in providing energy recovery options. Further discussion of gasification systems is provided in Chapter 5.

4.4.3

PAH emissions

Wenborn et al. (1999) have surveyed the literature for PAH emission factors for industrial combustion of wood. Table 4.17 summarizes the emission factors they identified. The investigators note that there are limited measurement data available and that there is high uncertainty in the activity data for industrial wood combustion. The lower bound figures reported in Table 4.17 are for the range of PAH emission factors from industrial combustion of wood as reported by US data for industrial wood-burning plants with end-of-pipe emission control technology. The investigators report a Radian Corporation 1995 study but do not provide the full reference. The upper bound emission factors are the default emission factors developed in their study for domestic wood combustion, which is assumed to broadly represent industrial plants with poor combustion and no emission controls. Emission factor data from additional literature sources cited in the study are taken into account. The default (‘‘best’’) emission factors for UK plants have been taken as the middle of the emission factor range in the table. The width of the emission factor ranges shows the significant uncertainty in the estimated emissions.

132

Handbook of Pollution Prevention and Cleaner Production

Table 4.17 PAH emission factors in mg/metric ton of wood for industrial wood combustion PAH

Minimum Maximum Best estimate (default) Data quality

Naphthalene Acenaphthylene Acenaphthene Fluorene Anthracene Phenanthrene Fluoranthene Pyrene Benzo[a]anthracene Chrysene Benzo[b]fluoranthene Benzo[k]fluoranthene Benzo[a]pyrene Dibenzo[a,h]anthracene Indeno[1,2,3-c,d]pyrene Benzo[g,h,i]perylene

2800 90 10 30 30 230 40 30 10 10 1 10 2 1 2 4

90,030 78,600 3100 8300 6500 24,400 6900 7300 5000 3800 1500 500 1300 20 90 1000

46,600 39,300 1600 4200 3300 12,300 3400 3700 2500 1900 800 300 650 10 40 500

Total

3300

238,340

121,100

D D D D D D D D D D F F D F F D

Source: Wenborn et al. (1999).

4.5 Emission factors for other wood manufacturing practices The focus of the first four chapters and the next is on wood preserving; however, the wood production industry sector is more diversified than wood treating. Other wood manufacturing sectors include:          

pulpboard manufacturing particleboard manufacturing plywood manufacturing medium-density fiberboard (MDF) manufacturing oriented strandboard (OSB) manufacturing hardboard (HB) manufacturing fiberboard (FB) manufacturing laminated veneer lumber manufacturing furniture manufacturing miscellaneous.

Each of these manufacturing sectors generates air emissions from various process operations. A good source of information on emission factors is the EPA’s electronic WebFIRE (http://cfpub.epa.gov/oarweb/index.cfm?action¼fire. main). A summary of the emission factors for the above manufacturing sectors

Air pollution from wood treatment

133

downloaded from the US EPA’s WebFIRE library is tabulated in the Appendix. In applying the emission factors reported in the table the reader should note the following column entries:     

Source – identifies the emission source. Pollutant – denotes the air pollutant. Method of control – indicates whether the emission factor was measured from a source that was uncontrolled or had a pollution control. Value – emission factor value in scientific notation. For example, a value of 1.2Eþ02 is the same as 120. Emission factor:  Unit – the unit that the emission factor is reported in.  Measure – the per-unit basis of the emission factor.  Material – the per-unit basis of material that the emission factor is reported for.  Action – the action under which the per unit basis of the emission factor was measured. As an example, the first entry in the table is for the emission source ‘‘Paperboard, general’’. The uncontrolled emission factor reported for VOCs is 0.2 lb of VOCs per ton of finished product.  EF quality – the EPA’s rating of the reported emission factor. See earlier in the chapter for an explanation of the EPA’s rating system.

References Chagger, H.K., Kendall, A., McDonald, A., Pourkashanian, M., Williams, A., 1998. Formation of Dioxins and Other Semi-volatile Organic Compounds in Biomass Combustion. Applied Energy 60 (2), 101–114. DaRos, R.M., Willard, H.K., Wolbach, C.D., 1982. Emissions and Residue Values from Waste Disposal During Wood Preserving. EPA-600/S2-82-062. US Environmental Protection Agency, Cincinnati, OH, August. Forintek Canada Corp., 2006. Canadian Lumber Kiln VOC Emissions; http://www. forestprod.org/drying06powerpoints.html Gallego, E., Roca, F.J., Perales, J.F., Guardino, X., Berenguer, M.J., 2008. VOCs and PAHs Emissions from Creosote Treated Wood in a Field Storage Area. Science of the Total Environment 402, 130–138. Ingram Jr., L.L., Tarlton, K., 2005. Effect of Physical Properties of Pentachlorophenol and Creosote Components on Vaporization from Treated Wood: Review of Prior Data. Forest Products Journal 55 (6) 86–89. Lavric, E.D., Konnov, A.A., De Ruyck, J., 2004. Dioxin Levels in Wood Combustion – A Review. Biomass and Bioenergy 26, 115–145. Milota, M.R., 2000. Emissions from Wood Drying, the Science and the Issues. Forest Products Journal; http://www.allbusiness.com/agriculture-forestry/forestry-loggingforest-nurseries/710042-1.html, accessed 1 June. NC DENR, 1998. Estimating Emissions from Generation and Combustion of ‘‘Waste’’ Wood, First Draft. Prepared for Division of Air Quality by Wood Waste and Furniture Emissions Task Force 15 July.

134

Handbook of Pollution Prevention and Cleaner Production

Oehme, M., Zuller, M., 1995. Levels and Congener Patterns of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in Solid Residues from Wood Fed Boilers: Influence of Combustion Conditions and Fuel Type. Chemosphere 30 (8), 1527– 1539. Salthammer, T., Klipp, H., Peek, R.D., Marutzky, R., 1995. Formation of Polychlorinated Dibenzo-p-dioxins (PCDD) and Polychlorinated Dibenzofurans (PCDF) During the Combustion of Impregnated Wood. Chemosphere 30 (11), 2051–2060. US Environmental Protection Agency (EPA), 1983. Health and Environmental Effects Profile for Tetra-, Penta-, and Hexachlorodibenzofurans, EPA-600/X-84/114. Office of Health and Environmental Assessment, EPA, Cincinnati, OH, p. 1–1. US Environmental Protection Agency (EPA), 1984. Health Assessment Document for Polychlorinated Dibenzo-p-dioxins, EPA-600/8-84-014A. Office of Health and Environmental Assessment, EPA, Washington, DC, pp. 3–5. US Environmental Protection Agency (EPA), 1995. US Forest Service, 1963. Study of Temperature in Wood Parts of Houses Throughout the United States. US Forest Research Note FPL-012, August. Wenborn, M.J., Coleman, P.J., Passant, N.R., Lymberidi, E., Sully, J., Weir, R.A., 1999. Speciated PAH Inventory for the UK, Report AEAT-3512/REMC/20459131/ISSUE 1. AEA Technology Environment, Culham, Abingdon, UK, August.

5 Pollution prevention and best practices for the wood-preserving industry 5.1 Introduction This chapter provides general guidance on pollution prevention and best practices for wood-treating facilities. While modern wood-treating plants are considerably less polluting than they were two decades ago, we still classify this as a ‘‘dirty’’ industry if, for no other reason, because of its dependence on chemicals that are toxic and carcinogenic. The National Institute of Occupational Safety and Health (NIOSH, 1977) has reported that: . based on a review of the toxicologic and epidemiologic evidence presented, it has been concluded that some materials contained in coal-tar pitch, and therefore in coal tar, can cause lung and skin cancer, and perhaps cancer at other sites. Based on a review of experimental toxicologic evidence, it is also concluded that creosote can cause skin and lung cancer. While the evidence on creosote is not as strong as that on pitch (in part because of difficulties in chemical characterization of such mixtures), the conclusion on the carcinogenic potential of creosote is supported by information on the presence of polynuclear aromatic hydrocarbons and imputations and evidence of the carcinogenicity of such hydrocarbons.

The American Wood Preserves Institute (AWPI) and railroad industry have argued since the late 1970s, when the US Environmental Protection Agency (EPA) first sought to ban creosote, pentachlorophenol, and arsenical treating chemicals, that there are no effective substitutes for these chemicals. Indeed, the scientific and industry studies all support that these chemicals are the most effective in killing pests and fungi, and in destroying agents that cause the decay of engineered wood articles. The market for treated wood products made from these chemicals is driven by the railroad and utilities sectors, who have ignored that there are other engineered materials that are more environmentally friendly that can replace their use. Figures 5.1 and 5.2 show photographs of concrete railroad ties and utility poles as examples. These photographs were taken in Ukraine. Throughout most of Europe, many parts of Latin America, and in the Middle and Far East, steel and concrete have been employed for decades in lieu of treated wood products for the same structural applications shown in these photographs. Both steel and concrete have better weather resistance and longer service life compared to any treated wood article, and they are completely impervious to the pests that treated wood is supposed to destroy. Handbook of Pollution Prevention and Cleaner Production Vol. 2 Copyright Ó 2010 by Elsevier Inc. All rights reserved.

136

Handbook of Pollution Prevention and Cleaner Production

Figure 5.1 Photograph of concrete railroad ties.

It has long been argued that the cost of making steel or concrete utility poles and railroad ties is greater than that of treated wood. The cost savings argument offered by proponents of chemically treated wood is not defensible when we take into consideration the costs incurred from environmental and health-related damage inflicted by the wood-preserving industry. Since 1980, the EPA has classified 56 wood-preserving sites as Superfund sites. At about 40 of these sites, the EPA has completed the process of selecting a cleanup strategy for the soil, sludge, sediments, and water contaminated by wood treatment wastes. If we conservatively assume that remediation costs are $20 million per site then the cost to American taxpayers can exceed $1.1 billion. Add to this the costs for medical monitoring for communities that have been exposed to air pollution or whose groundwater has been contaminated, or continue to receive toxic emissions from contaminated soils that become airborne, or are subjected to the pollution from wood-waste boilers, as well as healthcare costs from workers and community members who are battling illnesses from chemical exposures, then the manufacturing costs savings vanish. Both New Jersey and New York have banned the manufacture and use of creosote-treated wood. We believe this is a prelude to the demise of the industry and has long been overdue. The industry

Pollution prevention and best practices for the wood-preserving industry

137

Figure 5.2 Photograph of concrete utility pole in service.

on the whole has misrepresented the dangerous nature of the chemicals it uses, has failed to act responsibly in reporting its emissions accurately, has not been transparent in quantifying its emission sources, and has misrepresented that the benefits these products bring to society outweigh the negative impacts. Until the use of these chemicals is eliminated or is more severely restricted as in other industrialized nations, the industry should be obliged to use the best available technologies and practices to control emissions and discharges. The following section provides a summary of recommended practices.

5.2 Recommended best management practices and technologies Wood-treating facilities should have written Spill Prevention and Countermeasures Plans. Employees should be trained and programs should be strictly enforced. Elements that should be included are: 1. Spills of any size should be responded to immediately. Spills should be contained by diking and using appropriate adsorbents to soak up and amalgamate the chemical.

138

Handbook of Pollution Prevention and Cleaner Production

2. No spilled material should be fed to wood-waste boilers. 3. Consolidated spilled materials should be drummed, segregated, provided with proper hazardous waste labels and placards, provided with secondary containment, properly manifested, and shipped for off-site disposal in accordance with the Department of Transportation (DOT) HMR181 regulations (HMR stands for Hazard Materials Regulations). 4. Spill incidents should be monitored. The number of spills occurring over any one period should be documented and posted for employees to gauge progress towards elimination. Targets should be established to reduce spill-related incidents. 5. For every spill incident a root cause analysis should be performed so that formal recommendations leading to corrective actions are made to prevent recurrence. The causes and the recommendations should be relayed to workers in a timely and efficient manner. 6. Facilities should invest in, train, and apply an environmental management information system (EMIS). There are a number of EMIS software packages that are commercially available that will enable the environmental manager to monitor spill incidents both graphically and in tabular form. These same software systems are equipped with calendar and email functions that allow the environmental manager to quickly disseminate information, recommendations, findings, and corrective actions in an automated and timely fashion. 7. Corrective actions identified from root cause assessments of spills should focus on preventive measures. Examples include preventive maintenance, more frequent worker training and education, or operational changes. 8. Bulk storage facilities should be designed and constructed to contain any leaks or spills. 9. Drums, carboys, or other containers of coal-tar products should be closed while they are being moved or handled. Material from these containers shall be transferred carefully to prevent splashes, spills, or other circumstances by which employees may come into contact with coal-tar products. 10. Leaking containers should be isolated in adequately ventilated areas, or the coal-tar products contained therein shall be transferred to an intact container. Employees performing such operations should wear appropriate personal and respiratory protective equipment. 11. Shipping containers to be recycled should be completely drained and securely sealed. Coal-tar products should be cleaned from the outside surfaces of these containers. 12. Coal-tar products shall be transferred to or from tank trucks, cars, or other vessels only at facilities designed and designated for such operations. The wheels of the tank vehicle should be chocked, and vessels secured. Warning signs should be displayed, and barriers erected to prohibit entry of unauthorized personnel. Connections of the tank and the transfer system should be compatible and clearly identified. Only trained, authorized persons may carry out the procedures. The tank car or truck must be electrically grounded and bonded to the transfer line and receiving tank.

For drip pads: 1. Frequent inspections for surface cracks, fissures, and other signs of deterioration should be made. The US EPA has drip-pad standards that explain recommended inspection frequencies and maintenance practices.

Pollution prevention and best practices for the wood-preserving industry

139

2. Adapt EMIS software applications so that inspections and repairs are placed on automated emails for assignments, followup, and completion of work orders. 3. Drip pads should be equipped with either overhead sheds or secondary containment in order to prevent storm water from becoming contaminated. 4. Workers that are instructed to steam clean drip pads should wear respirators. Steaming action will produce aerosols that contain treatment chemicals. These may be inhaled or ingested by workers.

To minimize drippage (known as kickback): 1. Treated wood should be held within cylinders under vacuum and on drip pads until kickback is eliminated. There are no standard guidelines for these lengths of times or vacuum conditions. They are a function of the plant’s operating conditions. Guidelines should be established based on experience. a. Kickback can be measured by visual observation and also by collecting samples on the drip pad. Operators should gather such data in order to establish minimum written guidelines that can be incorporated into standard operating procedures (SOPs). 2. Treated wood should be stockpiled only in areas where there is appropriate capping and/or barriers for containment. 3. Visible signs of staining in treated wood staging areas should be documented, tested for contaminants, and remediated.

To minimize and control fugitive emissions and worker exposures: 1. Frequent air monitoring near cylinder doors should be performed. Action levels for respiratory protection should be established based on the air monitoring results. When in doubt, operators should be required to have respiratory protection. 2. Treated wood that is free from kickback should be held on site for the minimum amount of time. It is generally a good idea to maintain low inventories of treated wood since volatile emissions may persist for more than 90 days. 3. Workers should not be permitted to handle freshly treated wood without appropriate respiratory protection and chemical protective clothing. Freshly treated wood emits the highest levels of fugitive emissions and without impervious gloves, clothing and other skin protection, workers can be exposed through skin adsorption. 4. Treated wood stacking configurations should be changed in accordance with seasonal conditions. Summer months expose treated wood surfaces to high skin temperatures, making polycyclic aromatic hydrocarbons (PAHs) more volatile. Calculations show that mass emissions can be twofold greater during July and August in states like Louisiana than at other times during the year. This can lead to acutely poor air quality for both workers and neighbors. Other techniques include covering wood or placing plastic shielding around freshly treated wood to reduce fugitive air emissions. 5. Older facilities should test exposed soils for PAHs, pentachlorophenol, dioxins, and/ or arsenic if these chemicals were historically used or treated wastes were burned and ash buried on the property. Poor housekeeping practices were common among older facilities even less than a decade ago. Long-term poor housekeeping practices may have contaminated soils in certain areas of plant properties. These can be continuing sources of fugitive contaminated dust emissions resulting from heavy machinery and vehicular traffic across plant roads and in stockyard areas.

140

Handbook of Pollution Prevention and Cleaner Production

6. Airborne dust samples should be periodically collected and sampled for coal-tar pitch volatiles (CTPVs) and other contaminants to ascertain potential worker and community exposures. Dust suppressant methods such as water spraying or spraying with biodegradable oil–water mixtures should be practiced to control these emissions. 7. Inspect cylinder door seals before loading and after unloading visually and perform pressure testing on cylinders at least once per year. Seal ruptures can lead to catastrophic spills and air emission releases. Root causes for such events should be thoroughly investigated and a root cause analysis performed to identify causes and remedies. Such events should be monitored and reported along with aggressive spill monitoring and reporting. The health and safety manager should incorporate inspections, tracking, scheduled maintenance, and corrective actions into the EMIS. 8. Install overhead hoods above treating cylinder doors to collect fugitive emissions and treat these with either wet scrubber or selective catalytic reduction (SCR) burner technologies. This will make the system self-contained and eliminate all doubt of fugitive emissions from cylinders. 9. Most facilities vent cylinder emissions to knockout drums with spargers. The chemical industry has long recognized this technology to be a minimal method of control for volatile organic compound (VOC) emissions. For PAH emissions knockout drums are even less efficient since PAHs are not highly soluble. This technology can be upgraded using SCR burner technologies.

To reduce sludge and other solid wastes: 1. Clean treating cylinders on a regular basis. Many facilities generally inspect and clean treating cylinders on a yearly basis. More frequent and aggressive schedules may be needed depending on the operating conditions, service factors, and quality of wood treated. 2. Inspect all wood that is charged to treating cylinders. Establish a practice whereby all foreign matter including sand, grit, and sawdust is removed from green wood prior to treatment. This will not only reduce the generation of sludge, but will achieve cost savings by reducing the need for more frequent cylinder cleanings as well as improve product quality. 3. Discontinue the use of wooden spacers. Some facilities use kiln sticks to separate wood articles charged on trams to cylinders in order to improve the chemical coverage. These spacers result in a solid waste stream. They can be replaced with metal chains or spacers that can be reused. 4. Insist on high-purity chemical feedstocks. Creosote coal tars and extended oils should have low and tight product specs for moisture and inert materials. Insist on assays from chemical suppliers. This will not only reduce sludge generation but will result in direct cost savings since chemicals are purchased in bulk. This practice will also improve treated wood product quality. 5. If any facility is currently operating without an ISO 9001 product quality assurance certification of its products, it should consider going out of business. In this day and age there is no excuse not to have the practices of ISO 9000 quality control and assurance fully implemented at a plant and along the company’s supply chain. The principal objective of ISO 9000 is to continually improve product quality by adopting a policy of zero defects. Tracking defects, identifying root causes, and implementing corrective actions to reduce them on a continual basis can reduce waste and inefficiency. The obvious benefit from improved quality are direct cost savings, ability to

Pollution prevention and best practices for the wood-preserving industry

141

command premium prices for superior products, and reduced solid and chemical wastes. 6. Frequently inspect and clean storage tanks. Sludge accumulation in tanks can result in periodic downstream transfers, which contaminate treating cylinders and result in more costly cleanouts and cleanup of kickback.

To reduce point source emissions: 1. Eliminate the use of conical and tepee burners. These are rarely used today compared to a decade ago, but still some facilities may rely on them. They are highly polluting even when untreated wood is the only material being burned. 2. Consider replacing wood-burning boilers with natural gas-fired boilers or, at the very least, retrofit for co-firing. Natural gas is the cleanest burning fuel. The combustion of untreated wood still produces dioxins. 3. If wood-fired boilers continue to be employed for steam generation, test for chlorine levels in the wood fuel and make sure wood fuel is not stored in locations where salts and chlorine can be absorbed into the wood waste. The presence of chlorine will promote dioxin formation. 4. Some facilities have waste-to-energy programs where they accept and burn treated wood scrap such as railroad ties. We do not necessarily oppose this concept provided safeguards are implemented to eliminate dioxin and furan production. Permits to operate boilers generally require demonstration through formal stack testing. A problem we perceive is that permits are violated during startup and transient modes of operation, and facilities often become lax in operational requirements, which leads to periods of unacceptable stack emissions. We therefore recommend the following: a. Perform continuous emissions monitoring (CEM). Periodic opacity monitoring unto itself is unreliable and subject somewhat to interpretation. b. Low and tight metals specs should be established for treated waste wood that is accepted as a fuel supplement. c. A specification should be established for moisture and grit content. The fuel supplement should be treated wood – not sludge, grit, sand, metal, or other foreign objects. This requires a well-defined set of feed quality assurance protocols. d. The treated wood should be metered into the main feed stream at specified rates. Metering does not mean dumping drum loads of treated scrap on to a conveyor belt as we have identified at some facilities. The treated scrap should be chipped to a certain size fraction and fed by means of a double auger according to a tightly controlled mass rate that is consistent with the operating permit. e. Only treated waste that meets a minimum calorific content should be accepted. This minimum level is often tied to the operating permit, but not always. In any case, it should be greater than the Btu content of the primary feed (untreated wood) in order to ensure hotter, more efficient burning. f. Stack testing should be extended to confirm that post-dioxin formation does not occur in pollution controls. Electrostatic precipitators, for example, have been found to operate in particle temperature and residence time regimes that promote dioxin formation via the mechanism of de novo synthesis. De novo synthesis can be controlled or eliminated by proper air irrigation and adoption of wall rapping mechanisms on the control device. g. Backup or secondary pollution controls should be considered. Most wood-waste boilers are only equipped with simple primary pollution controls such as cyclones,

142

Handbook of Pollution Prevention and Cleaner Production

multi-clones, or baghouses. These are inadequate because they are dry collection devices. PAH emissions from wood-waste boilers are both particulate matter and gaseous. Secondary pollution controls are needed to ensure PAHs achieve at least three nines of destruction and removal efficiency (DRE). Afterburners or SCR technologies are the most dependable types of pollution controls for this purpose. h. Furnace grates should be regularly inspected to minimize ash buildup and reentrainment. The ash should be tested and classified for heavy metals and contained and disposed of in accordance with Resource Conservation and Recovery Act (RCRA) rules. i. Boiler operators should be trained licensed operators only and should be required to take yearly refresher or recertification programs. j. The treated wood feed system should be equipped with automatic shutoff controls such that when stack opacities exceed allowable limits, the supplemental fuel feed shuts down.

To reduce worker exposure, the following is the standard of care that was established by the NIOSH in 1977 and reiterated by the Occupational Safety and Health Administration (OSHA, 1978). These have been the best practices recommended by these authoritative bodies for the past 30 years: 1. Occupational exposure to coal-tar products should be controlled so that employees are not exposed to coal tar, coal-tar pitch, creosote, or mixtures of these substances at a concentration greater than 0.1 mg/m3 of the cyclohexane-extractable fraction of the sample, determined as a time-weighted average (TWA) concentration for up to a 10-hour work shift in a 40-hour working week. 2. All containers of coal-tar products should bear the following labels in addition to, or in combination with, label information required by other statutes, regulations, or ordinances: HARMFUL TO THE SKIN, OR IF INHALED OR SWALLOWED CAUSES BURNS OF EYES AND SKIN AND MAY CAUSE CANCER Do not breathe dust, fume, or vapor Do not get in eyes, on skin, or on clothing Do not take internally Use only with adequate ventilation Wear goggles, face shield, gloves, and protective clothing when handling In case of contact, immediately flush eyes with plenty of water or skin with soap and water. Remove contaminated clothing and shoes. Wash clothing before reuse. Call physician in case of chemical or thermal burns. 3. In all areas where there is occupational exposure to coal-tar products the following list should be posted in readily visible locations at or near all entrances to the area and on or near all equipment used for handling or containing coal-tar products: DANGER CANCER HAZARD AUTHORIZED PERSONNEL ONLY COAL-TAR PRODUCTS IRRITATING TO SKIN AND EYES NO SMOKING OR EATING

Pollution prevention and best practices for the wood-preserving industry

143

4. The NIOSH recommends that employers use engineering controls when needed to keep the concentration of airborne coal-tar products at or below the limit specified. Employers should also provide protective clothing and equipment impervious to coal-tar products to employees whenever liquid coal-tar products may contact the skin or eyes. Emergency equipment should be located at wellmarked and clearly identified stations and should be adequate to permit all personnel to escape from the area or to cope safely with the emergency on re-entry. 5. The NIOSH recommends cup-type or rubber-framed chemical safety goggles be worn by employees engaged in activities in which coal-tar products may come in contact with the eyes. When employees are exposed to airborne coal-tar products at concentrations in excess of the limits specified a respiratory protective device with a full face piece is required; this will also provide adequate eye protection as required by 29 CFR 1910.133. a. Full-length, plastic face shields (20 cm minimum) shall be worn, in addition to safety goggles, by employees working where contact with coal-tar products is likely, except where full-face-piece respirators are being worn. 6. For protective clothing the NIOSH recommends that employers provide, and require employees working with creosote to wear, gloves, protective sleeves, aprons, jackets, trousers, caps, and shoes as necessary to prevent skin contact with creosote. These garments shall be made of a material resistant to penetration by creosote, such as polychloroprene, polyethylene, rubber, or other suitable material. a. Employers shall provide, and shall require employees working with creosote to wear, suitable clothing to prevent skin contact with coal tar. These garments shall be made of a material resistant to penetration by coal tar. For employees working with heated coal-tar pitch, employers shall require use of protective clothing sufficient to prevent skin contact. 7. The NIOSH recommends that the employer ensure that, at the completion of the work shift, all protective clothing is removed only in the changing rooms. It further recommends that the employer shall ensure that contaminated protective clothing that is to be cleaned, laundered, or disposed of is placed in a closed container in the changing room. 8. At the beginning of employment or assignment for work that may involve exposure to coal-tar products in the occupational environment, the employer shall inform each employee of the hazards of such employment and of the possible injuries resulting from exposure to coal tar products. This comes under the Hazard Communication Act, better known as Right-to-Know. The employee shall be instructed in the proper procedures for safe handling and use of coal-tar products, in the operation and use of protective systems and devices, and in appropriate emergency procedures. Employers are required to institute a continuing education program, conducted by persons qualified by experience or special training, to ensure that all employees have current knowledge of job hazards, proper maintenance procedures, cleanup methods, and correct use of respirators. a. The instructional program shall include a description of the medical and environmental surveillance procedures and the advantage to the employee of participation in these procedures. Required information shall be recorded on a ‘‘Material Safety Data Sheet’’. This information shall also be made available in the work area and kept on file, readily accessible to employees at any place of employment where exposure may occur.

144

Handbook of Pollution Prevention and Cleaner Production

9. Spills and leaks of creosote shall be cleaned up immediately. Employees engaged in cleanup operations shall wear suitable protective clothing, equipment, and respiratory devices. Spills and leaks of other coal-tar products shall be cleaned up after allowing necessary time for cooling. Employees instructed and trained in the procedures for safe decontamination or disposal of equipment, materials, and waste shall perform or directly supervise cleanup operations. All other persons shall be excluded from the area of the spill or leak until cleanup is complete and safe conditions have been restored. 10. Storage conditions should be controlled to prevent overheating and pressure buildup in containers of coal-tar products. Transfer and storage systems should be designed and operated to prevent blockage by condensed coal-tar products. 11. Emergency showers and eyewash fountains should be provided at locations readily accessible to all areas where coal-tar products may contact the skin or eyes. 12. Protective clothing, respirators, goggles, and other personal protective gear that has been contaminated by coal-tar products shall be thoroughly washed or cleaned before reuse by any employee. Persons who launder or clean contaminated protective equipment shall be advised of the hazards associated with handling such equipment and of procedures needed to prevent these hazards. The NIOSH has reported that contaminated shoes increase the risk of skin contact with coal-tar products and should be decontaminated or discarded. 13. Employers should ensure that all protective equipment is regularly inspected and maintained and that damaged items are repaired or replaced. 14. Each operation in each work area shall be sampled at least once every 3 months. If an employee is found to be exposed to airborne coal-tar products at concentrations in excess of the limit specified by the NIOSH/OSHA, the exposure of that employee shall be measured at least once a week, control measures shall be initiated, and the employee shall be notified of the extent of the exposure and of the control measures being implemented to reduce the concentration of airborne coal-tar products to or below the limit. Such monitoring shall continue until two consecutive determinations, at least 1 week apart, until the employee is no longer exposed to airborne coal concentrations greater than the threshold limit value (TLV) limit whereby monitoring may then be resumed.

To improve overall environmental performance, facilities should formally adopt and implement an environmental management system (EMS). A formal EMS when properly implemented will enable a facility to not only meet its minimum compliance obligations but to exceed them. We believe that most of industry is fixated on meeting compliance obligations as opposed to good environmental performance. The basis for this statement is that it is common among companies to heavily discount and even ignore those costs for compliance associated with intangible elements leading to future liabilities because of a false sense of security derived from meeting minimum current regulatory obligations. When a company looks at their operations only from a compliance standpoint, there is a tendency to focus on current regulations with perhaps no more than a few years of foresight into how regulations may become more stringent over time and their subsequent impacts to their business. While no one has a crystal ball that can predict changing regulatory climate, history has shown that over the long run and worldwide, there has been

Pollution prevention and best practices for the wood-preserving industry

145

a tightening of regulations across all forms of pollution media. Clearly companies are in a position to assess their potential liabilities and, if nothing else, determine with some degree of confidence that their business operations pose certain risks, and that those risks can result in financial liabilities at some point in time. Future liabilities when sizeable, and especially for large companies that have ‘‘deep pockets’’ and can sometimes be big targets for the press, can be especially vulnerable. Future liabilities associated with large remedial actions from past environmental damages run the risks of incurring negative impacts from the less tangible costs such as a negative public image and loss of investor confidence. But even when the more astute business decision-makers realize the risks, there are various reasons or, perhaps more appropriately, excuses for discounting future and less tangible costs: 1. ‘‘We don’t have a crystal ball and can’t predict with reasonable accuracy how regulations may change or become more restrictive in the years to come.’’ 2. ‘‘There are no formal guidelines for unsafe exposures that currently exist for the chemical wastes we generate. We therefore don’t believe the added costs for segregation, stabilization, on-site treatment or off-site disposal to a secure location are justified.’’ 3. ‘‘We meet our regulatory obligations. Everything we do is within what is allowed by the state we operate our business in. Since we are following the law, we have no exposure.’’ 4. ‘‘We convinced our state environmental regulators that our current waste management practices are adequate and they are issuing us permits. We have nothing to worry about now and in the future.’’ 5. ‘‘We don’t need to worry about any future liabilities because we engaged a company that will manage our wastes. But in addition we cleverly structured an agreement whereby they accept 100% of all the liabilities associated with the wastes we have contracted them to remove from our property and dispose of.’’

These types of anecdotal statements have led to tens of millions of dollars in legal fees over disputes that are in the league of hundreds of millions of dollars in settlement damages, plus they have placed large numbers of communities at continued risks from exposure to poor environmental practices that were not regulated in years past, but certainly could have been averted with readily available technologies and commonsense practices.

5.3 Cleaner production through gasification We suggest gasification as one area of cleaner production technology investment for the industry sector. Gasification is the process where carbonaceous materials, such as biomass or coal, react with steam or a limited amount of air or oxygen, producing a gaseous fuel. The products of gasification are mainly carbon monoxide and hydrogen, with minor amounts of carbon dioxide, methane, and other hydrocarbons. Gasification differs from normal combustion, the aim of

146

Handbook of Pollution Prevention and Cleaner Production

which is to efficiently burn the fuel and create a hot gas stream that can be used to generate steam in a boiler. In a conventional wood-waste boiler, a balance between the mixture of oxidizer (air) and fuel must be achieved in order to ensure high combustion efficiency. The art of good combustion also requires that the combustion system must be robust enough to provide adequate mixing or turbulence, residence time, and high enough temperatures in order to achieve extremely high DREs that ensure PAHs and dioxins are not generated as products of incomplete combustion. Because this balancing act can be difficult to achieve depending on the composition and variation in properties of the feed, especially when alternative fuels such as treated wood or sludge are fed to the boiler, pollution controls must also be added. In contrast, gasification simplifies the balancing act and removes the need for an operator to control the air-to-fuel ratio within a critical range. Gasification as a general technology is rather old. The gasification process was originally developed in the 1800s to produce town gas for lighting and cooking. Wood gasifiers, called Gasogene or Gazoge`ne, were used to power motor vehicles in Europe during World War II fuel shortages. The economies of a wartime environment forgave the unfavorable economics of these systems and in postwar times, when the world returned to inexpensive oil for decades, this technology fell into the lost annals of history. The energy crisis of the 1970s brought a renewed interest. The technology was perceived as a relatively cheap indigenous alternative for small-scale industrial and utility power generation in those developing countries that suffered from high world market petroleum prices and had sufficient sustainable biomass resources. In the beginning of the 1980s at least 10 (mainly European) manufacturers were offering small-scale wood- and charcoal-fired power plants (up to approximately 250 kWel). At least four developing countries (Philippines, Brazil, Indonesia, India) started gasifier implementation programs based on locally developed technologies. Hundreds of biomass gasification systems were installed through donor-financed projects and local entrepreneurs in a large number of developing countries. In Western countries coal gasification systems became of interest during the 1980s as an alternative for the utilization of natural gas and oil in dedicated heating applications. Technology development was mainly addressed to fluidized-bed gasification systems for coal, but also for biomass. These were typically in the range of 10–100 MWth. Currently the development of gasification systems is directed to the production of electricity and heat in advanced gas turbinebased co-generation units. There are three fundamental steps to gasification: 1. Pyrolysis – particles are heated (>700 C (1292 F)) in the absence of oxygen and release volatile matter. The following reaction occurs: Fuel þ Heat / Hydrogen þ Tars þ Methane þ Char. 2. Combustion – volatile products and some of the char reacts with oxygen to form carbon dioxide and carbon monoxide, which provides heat for the subsequent gasification reactions. Pyrolysis and combustion are very rapid processes. The reaction is: Char þ Tars þ Methane þ Oxygen / Carbon dioxide þ Carbon monoxide.

Pollution prevention and best practices for the wood-preserving industry

147

3. Gasification – the char reacts with carbon dioxide and steam to produce carbon monoxide and hydrogen. The resulting gas is called producer gas or syngas (or wood gas when fueled only by wood). The reaction is: Char þ Carbon dioxide þ Steam / Carbon monoxide þ Hydrogen.

A typical composition of wood gas is 51% nitrogen, 27% carbon monoxide, 14% hydrogen, 4.5% carbon dioxide, 3% methane, and 0.5% oxygen. Rezaiyan and Cheremisinoff (2005) have studied small-scale gasification systems that use coal, mixed municipal refuse, and various biomass feedstocks. None of these systems has reported any detectable levels of dioxins, furans, or PAHs. The overall advantages of gasification are a smaller environmental footprint achieved through:     

reduced carbon dioxide emissions (greenhouse gas); reduced fossil fuel consumption; reduced SO2 and NOx emissions (acid rain gases); expanded range of uses of gas over solid fuels; allowing a method to produce hydrogen for fuel cells.

The technology is well suited for paper mill wastes and is discussed in a later chapter. While the process itself is relatively straightforward and even somewhat simple, there are a host of gasifier configurations and process innovations, each having certain operational and cost advantages. Characteristic of the several types of gasifiers is the way in which the fuel is brought into contact with the gasification stage. Four common types of reactors are:    

the up-draught or counter-current gasifier; the down-draught or co-current gasifier; the cross-draught gasifier; the fluidized-bed gasifier.

Up-draught or counter-current gasifiers are fixed-bed systems. In this configuration the biomass is fed in at the top of the reactor and moves downwards as a result of the conversion of the biomass and the removal of ashes. The air intake is at the bottom and the gas leaves at the top. The biomass moves in countercurrent to the gas flow, and passes through the drying zone, the distillation zone, the reduction zone, and the hearth zone. In the drying zone the biomass is first dried. In the distillation or pyrolization zone the biomass is decomposed in volatile gases and solid char. The heat for pyrolization and drying is mainly delivered by the upwards-flowing producer gas and partly by radiation from the hearth zone. In the reduction zone many reactions take place involving char, carbon dioxide, and water vapor, in which carbon is converted and carbon monoxide and hydrogen are produced as the main constituents of the producer gas. In the hearth zone the remaining char is combusted providing the heat, the carbon dioxide, and water vapor for the reactions involved in the reduction zone. Advantages of this type of gasifier are its simplicity, high charcoal burn-out and internal heat exchange, resulting in low gas exit temperatures and high

148

Handbook of Pollution Prevention and Cleaner Production

gasification efficiencies. Because of the internal heat exchange the fuel is dried in the top of the gasifier and therefore fuels with a high moisture content (up to 60% wet basis) can be used. This type of gasifier can process relatively smallsized fuel particles and accepts some size variation in the fuel feedstock. Drawbacks are the high amounts of tar and pyrolysis products, because the pyrolysis gas is not combusted. This is of minor importance if the gas is used for direct heat applications, in which the tars are simply burnt. If the gas is used for engines, extensive gas cleaning is required, which can add sizeable costs to the operation and investment. A variation is the down-draught or co-current gasifier. In this configuration the biomass is fed in at the top and the air intake is also at the top or from the sides. The gas leaves at the bottom of the reactor, so the fuel and the gas move in the same direction. The same zones can be distinguished as in the up-draught gasifier, although the order is somewhat different. The biomass is dried and pyrolized in the drying and distillation zones respectively. These zones are heated by radiation and partially by convection heat from the hearth zone, where a portion of the char is burnt. The pyrolysis gases also pass through this zone to be burnt as well. The extent to which the pyrolysis gases are actually burnt depends on design, the biomass feedstock, and the skills of the operator. After the oxidation zone the remaining char and the combustion products carbon dioxide and water vapor pass to the reduction zone, where the reduction reactions take place forming CO and H2. The primary advantage of a down-draught gasifier is the production of a gas with a low tar content that is nearly suitable for engine applications. Drawbacks of the down-draught gasifier are:  

 

high amounts of ash and dust particles in the gas due to the fact that the gas has to pass the oxidation zone collecting small ash particles; relatively strict requirements on fuel, which has to be uniformly sized in the range of 4–10 cm to achieve regular flow, no blocking in the throat, and enough ‘‘open space’’ for the pyrolysis gases to flow downwards and to allow heat transport from the hearth zone upwards – therefore pelletization or briquetting of the biomass is often necessary; the moisture content of the biomass must be less than 25% (on a wet basis); the relatively high temperature of the leaving flue gases resulting in a lower gasification efficiency.

This type of gasifier is used in power production applications in a range from 80 up to 500 kWel or more. Cross-draught gasifiers are adapted for the use of charcoal. Charcoal gasification results in very high temperatures (>1500 C) in the hearth zone, which can lead to material problems. Advantages of the system lie in the very small scale at which it can be operated. In developing countries, installations for shaft power under 10 kWel are common. This is possible due to the very simple gas-cleaning train (cyclone and a bed filter). A drawback is the minimal tarconverting capability, resulting in the need for high-quality charcoal.

Pollution prevention and best practices for the wood-preserving industry

149

Open-core gasifiers are designed to gasify fine materials with low bulk density (e.g. rice husks). Because of the low bulk density of the fuel no throat can be applied in order to avoid bridging of the fuel, which causes hampering or even stopping of the fuel flow. Special devices, like rotating grates, may be included to stir the fuel and to remove the ash. Rice husk gasifiers in particular require continuous ash removal systems because of the high ash content of rice husks, resulting in large volumes of ash (~55% of the initial fuel volume). The bottom of the gasifier is set in a basin of water by which the ash is removed. There are only a few commercial up-draught power gasifiers in operation, with all systems located in South America. In the 1940s and 1950s in Europe, however, a considerable number of systems were functioning on a diversity of fuels like wood residues and agricultural wastes. The last European up-draught power gasifier (in Germany) was decommissioned for environmental reasons (water pollution due to tarry residues). Hence most current fixed-bed gasifiers are of the down-draught type. Most down-draught gasifiers are provided with a V-shaped ‘‘throat’’; the oxidation zone is located in the narrowest part of this throat. The aim of this throat is to create a concentrated high-temperature zone and to force all pyrolysis gases through this zone in order to crack the tar. Air is fed directly into this zone by either a central air supply pipe or by air inlet nozzles located at the walls of the throat. In the choice of the throat diameter a compromise has to be found between decreasing the risk that tar-loaded gases escape from the oxidation zone and the flow rate of the fuel and the gas velocities in the throat. The latter should not be too high, to prevent ash being swept and collected by the gas stream causing high dust contents. More recent reactor designs are double walled. The producer gas is conducted through the space between the walls, allowing for heat exchange between the producer gas and the fuel in the pyrolysis and drying zone of the reactor. The effectiveness of this heat exchange is greatly improved when small reactor diameters are applied, enlarging the heat exchange surface area significantly. In some designs the pyrolysis gases that condense on the cover are drained through a pipe and collected in a tank. In the Delacotte gasifier system the pyrolysis gases are collected at the top of the gasifier and partly combusted and partly cracked in a separate reactor. The flue gases are then fed into the hearth zone of the gasifier and used to partly burn and partly gasify the charcoal. A relatively tar-free producer gas is the result. While there are a variety of gasifier designs, thus far fixed-bed gasifiers capable of producing a tar-free producer gas remain elusive. The turndown ratio for each basic type of gasifier is generally viewed as unsatisfactory. There are also operational and safety concerns. Explosions may occur as a result of leakage of combustible gases through the fuel feeding system, the ash discharge system or any other leakage point. After shutdown of a gasifier, combustible gases will remain in the equipment. If the gasifier is ignited again without venting the equipment in advance with fresh air, the combustible gases are still present and

150

Handbook of Pollution Prevention and Cleaner Production

may explode during ignition of the gasifier. To reduce the risk of explosions gasifiers should be located in well-vented rooms or in the open air. Fuel blockages may occur in the throat of the gasifier. These blockages are caused by an inappropriate combination of fuel properties, like morphology, size distribution, ash content and behavior, bulk density, and the flow properties of the derived char. The particular gasifier design needs to be adapted to the fuel properties. Corrosion may be a problem, especially on surfaces in the high-temperature areas of the gasifier such as the throat. Corrosion can be caused by too high temperatures and/or contaminants in the feedstock. The gasifier design should be adapted to lower the temperature and/or to use other heat-resistant materials. For relatively clean biomass feedstocks, corrosion is generally not an issue. Tar production can be an issue. Excessive tar production may be caused by inappropriate fuel properties like morphology, size distribution and moisture content, and inappropriate flow behavior of the char. Excessive tars may also be produced during periods of unsteady-state operation or too-low part load operation. The design of a gasifier should be appropriate to the fuel properties. The fluidized-bed gasifier has had greater success and is likely more suitable to mixed wood-waste streams containing supplemental fuels seen in the woodpreserving industry. Fluidized-bed gasification was originally developed to overcome the operational problems with fixed bed systems, particularly for fuels with high ash content. These systems are very suitable for larger capacities (larger than 10 MWth) in general. The features of fluidized-bed gasification are comparable with those of fluidized-bed combustion. Compared to fixed-bed gasifiers the gasification temperature is relatively low (750–900 C). In contrast, in fixed-bed gasifiers the temperature in the hearth zone may be as high as 1200 C, in charcoal gasifiers even 1500 C. Fuel is fed into a hot (sand) bed, which is in a state of suspension (bubbling fluidized bed) or circulating (circulating fluidized bed). The bed behaves analogously to fluid and is characterized by high turbulence (Cheremisinoff and Cheremisinoff, 1984). Fuel particles mix rapidly with the bed material, resulting in fast pyrolysis and a relatively large amount of pyrolysis gases. Because of the low temperatures the tar conversion rates are not excessive. The advantages of fluidized-bed reactors in comparison with fixed-bed reactors are:  



compact construction because of high heat exchange and reaction rates due to the intensive mixing in the bed; flexibility to changes in fuel characteristics such as moisture and ash content, along with ability to deal with fluffy and fine-grained materials with high ash contents and/ or low bulk density; low ash melting points due to the low reaction temperatures.

Disadvantages are:  

high tar and dust content of the produced gas; high producer gas temperatures containing alkali metals in the vapor state;

Pollution prevention and best practices for the wood-preserving industry

  

151

incomplete carbon burn-out; complex operation because of the need to control the supply of both air supply and solid fuel; the need for power consumption for the compression of the gas stream.

Carbon burn-out in circulating fluidized-bed gasifiers is better than in bubbling fluidized beds. The flexibility in particle size is not that high as compared to fluidized-bed combustion; for gasification relatively fine fuel particle sizes are preferred. Steam or pure oxygen is often used as a fluidizing and gasifying agent instead of air. If the gasification is done with pure oxygen the caloric value of the producer gas will be higher because of the absence of nitrogen (coming from the air) in the producer gas. However, production of oxygen is expensive and therefore it is only feasible in large-scale applications, for example in the largescale coal gasification power plant in Buggenum (the Netherlands). For the scale of biomass applications especially in wood preserving, however, an oxygen factory is not expected to be economic. Pressurized fluidized-bed gasification is likely well suited for wood-treating plants, especially if the opportunity exists to generate and sell power off site. These are suitable for power production in relatively large-scale applications ( 5 MWel) gas turbines. When used in a gas turbine, the producer gas has to be fed into the combustor at high pressures (10–25 bar, depending on the gas turbine design). As a consequence the hot producer gas from an atmospheric gasifier has to be cooled and compressed, resulting in a high level of internal power consumption. Gas cooling is necessary because the temperature of the gas increases due to the compression, and also the temperature resistance of compressors is limited. In addition, hot gases require large volumes and additional work is needed for compression. An alternative approach is to gasify under pressurized conditions, delivering producer gas at the pressure of the gas turbine combustor. Advantages of this approach are:   

low level of internal power consumption; compact design implying low specific investment costs; decrease of sintering behavior of the ash.

Whatever gasifier system is chosen, the downstream applications are flexible and offer significant green incentives. As an example, Primenergy (http://www. primenergy.com/Projects_detail_LittleFalls.htm) is a company that specializes in gasification. This company describes a scheme for wood-based biomass feed using a solid feed rate of 288 tons per day. A thermal oxidizer exhaust is used to produce 50,000 pounds per hour of high-pressure, superheated steam and to provide 35 million Btu per hour of thermal energy for drying duty. Superheated steam is sent to a backpressure turbine to produce approximately 1 MW of electricity and exhaust process steam for use in a host ethanol plant. Conceptually this same approach could be employed to operate drying kilns, provide steam to retorts, and generate electricity at a wood-treating plant. The

152

Handbook of Pollution Prevention and Cleaner Production

Primenergy process application is for an ethanol distillery. While the industry application is a far cry from a wood-treating plant, the plant internal applications are the same. Microturbines are a key to generating electricity for small economies of scale, as would be the case at medium-sized wood-treating plants. Microturbines are small combustion turbines that produce between 25 and 500 kW of power. Microturbines were derived from turbocharger technologies found in large trucks or the turbines in aircraft auxiliary power units (APUs). Most microturbines are single-stage, radial flow devices with high rotating speeds of 90,000–120,000 revolutions per minute. Some manufacturers have developed alternative systems with multiple stages and/or lower rotation speeds. Microturbines are well suited for wood-treating plants. These small combustion turbines are approximately the size of a refrigerator, with outputs of 25–500 kW. Microturbines offer a number of potential advantages over other technologies for small-scale power generation. These include their small number of moving parts, compact size, light weight, greater efficiency, lower emissions, lower electricity costs, and ability to use waste fuels. They can be located on sites with space limitations for the production of power, and waste heat recovery can be used to achieve efficiencies of more than 80%. By way of further background, turbines are essentially classified by the physical arrangement of their component parts: single-shaft or two-shaft, simple-cycle or recuperated, inter-cooled, and reheat. The machines generally rotate at more than 40,000 rpm. Bearing selection, whether the manufacturer uses oil or air, depends on the application. Single-shaft is the more common design because it is simpler and less expensive. Conversely, the split shaft is necessary for machine drive applications because it does not require an inverter to change the frequency of the AC power. Microturbines can also be classified as simple-cycle or recuperated. In simple-cycle, or unrecuperated, turbines, compressed air is mixed with fuel and burned under constant pressure. The resulting hot gas is allowed to expand through a turbine to perform work. Simple-cycle microturbines have lower cost, higher reliability, and more heat available for co-generation applications than recuperated units. Recuperated units use a sheet metal heat exchanger that recovers some of the heat from an exhaust stream and transfers it to the incoming air stream. The preheated air is then used in the combustion process. If the air is preheated, less fuel is necessary to raise its temperature to the required level at the turbine inlet. Recuperated units have a higher thermal-toelectric ratio than with unrecuperated units and can produce 30–40% fuel savings. These machines are compact in size, have relatively low capital costs, have low operations and maintenance costs, and are equipped with automatic electronic controls. A final application of the syngas product resulting from gasification is diesel production. Wood-treating plants use diesel oil to operate a variety of support equipment, plus it is suitable as an extender for the wood-preserving chemicals.

Pollution prevention and best practices for the wood-preserving industry

153

The syngas can serve as a feedstock to manufacture diesel and other liquid fuels. This can be accomplished by conversion of the syngas using the Fischer–Tropsch (FT) process. The FT process is a catalyzed chemical reaction in which carbon monoxide and hydrogen are converted into liquid hydrocarbons of various forms. Typical catalysts used are based on iron and cobalt. The principal purpose of this process is to produce a synthetic petroleum substitute for use as synthetic lubrication oil or as synthetic fuel. The original FT process is described by the following chemical equations: CH4 þ

1 O2 ¼ 2H2 þ CO 2

ð2n þ 1ÞH2 þ nCO ¼ Cn H2nþ2 þ nH2 O: The resulting hydrocarbon products are refined to produce the desired synthetic fuel. Carbon dioxide and carbon monoxide are generated by partial oxidation of the wood fuel. The utility of the process is primarily in its role in producing fluid hydrocarbons or hydrogen from a solid feedstock. Non-oxidative pyrolysis of the wood produces syngas, which can be used directly as a fuel without being taken through Fischer–Tropsch transformations. If liquid petroleum-like fuel, lubricant, or wax is required, the FT process can be applied. Finally, if hydrogen production is to be maximized, the water gas shift reaction can be performed, generating only carbon dioxide and hydrogen and leaving no hydrocarbons in the product stream. Shifts from liquid to gaseous fuels are relatively easy to make. Since the invention of the original process by the German researchers Franz Fischer and Hans Tropsch, working at the Kaiser Wilhelm Institute in the 1920s, many have been devised, and the term ‘‘Fischer–Tropsch’’ now applies to a wide variety of similar processes (Fischer–Tropsch synthesis or Fischer–Tropsch chemistry). The process was invented in petroleum-poor but coal-rich Germany in the 1920s, to produce liquid fuels. It was used by Germany and Japan during World War II to produce alternative fuels. Currently, two companies have commercialized their FT technology. Shell in Bintulu, Malaysia uses natural gas as a feedstock and produces primarily lowsulfur diesel fuels. Sasol in South Africa uses coal as a feedstock and produces a variety of synthetic petroleum products. The process is today used in South Africa to produce most of the country’s diesel fuel from coal by the company Sasol. The process was used in South Africa to meet its energy needs during its isolation under apartheid. This process has received renewed attention in the quest to produce low-sulfur diesel fuel in order to minimize the environmental impact from the use of diesel engines. A small US-based company, Rentech, is currently focusing on converting nitrogen-fertilizer plants from using a natural gas feedstock to using coal or coke, and producing liquid hydrocarbons as a byproduct. Also, Choren in Germany and Changing World Technologies (CWT) have built FT plants or use similar processes. The FT process is a well-established technology and is already applied on a large scale.

154

Handbook of Pollution Prevention and Cleaner Production

5.4 Commitment to pollution prevention and environmental management systems For those readers who are unfamiliar with an environmental management system (EMS) and how pollution prevention is integral to the management system, we offer the following discussion. According to the International Organization for Standardization (ISO), an EMS is ‘‘that part of the overall management system which includes organizational structure, planning activities, responsibilities, practices, procedures, processes and resources for developing, implementing, achieving, reviewing and maintaining the environmental policy’’. The elements of an EMS are outlined below.

5.4.1

Policy

Top management needs to clearly define the organization’s environmental policy. This written policy statement can apply to facilities, sites, and programs, appropriate to the scale of operation and impact of activities governed by the policy. Format and length can vary, but the policy must commit to relevant environmental legislation and regulations. It must provide a framework for setting and reviewing goals. The policy needs to be communicated to all employees, the public, and in fact along the entire supply chain that interacts with a business. The very first step in the implementation of ISO 14001 involves Clause 4.2, which recommends that a company make a commitment to pollution prevention as its top priority. There are no ‘‘boiler-plate’’ policy statements and indeed these statements can range from very general commitments to complying with environmental regulations and protecting the environment and reducing waste and pollution, to statements that reflect very specific targets and goals. The Environmental Policy statement can in fact reflect not just an overall policy but rather be viewed as a vision statement with specific targets and goals to achieve. The above examples reflect very specific goals and targets and are embedded within the general policy statements that commit to acting in a responsible manner for public safety, workforce safety, conserving resources, protecting the environment, and meeting compliance. They in turn are a reflection of core values, which relate back to good business practices that have to do with being profitable, competitive, sustainable, and acting in a responsible manner. Table 5.1 is a checklist that can aid in formulating the environmental policy statement.

5.4.2

Planning

Planning begins with identifying the environmental aspects of activities the organization controls (i.e. the components of those activities that are likely to interact with the environment) and understanding how those aspects impact on the environment. In a practical sense, once the policy and commitment on the part of top management are established and the message becomes clear

Pollution prevention and best practices for the wood-preserving industry

155

Table 5.1 Environmental policy checklist To what extent do the following statements apply to your policy? Not at all ¼ 1 point, absolutely ¼ 5 points 1. The environmental policy of your company is written 2. It is defined by management 3. Employees participated in defining the policy 4. It is reviewed at regular intervals 5. When changes occur in the company it is adapted 6. Employees are informed about the policy 7. It covers compliance with environmental legislation 8. It covers commitment to continuous improvement of environmental performance 9. The following site-related areas are taken into account: a. Energy b. Raw materials and water c. Waste d. Noise e. Production processes f. Product planning g. Environmental performance of contractors and suppliers h. Prevention of accidents i. Dealing with accidents j. Environmental protection and personnel k. Environment and public relations 10. The policy is understandable for employees 11. It is understandable for those outside of the company 12. It is goal oriented 13. It has well-defined targets for improvement 14. It is credible 15. It serves as a guide for employees 16. It helps employees to identify with the company 17. It is followed up with concrete measures and goals 18. It fits with the ability of management and employees 19. It is consistent with the overall goals of the company 20. It is supported and put into practice by management 21. It incorporates the needs of day-to-day operations and opens up possibilities as opposed to being a constraint Total Maximum no. of points possible (100%) ¼ 155 points Score obtained (%) ¼ points

1

2

3

4

5

156

Handbook of Pollution Prevention and Cleaner Production

throughout an organization, the company needs to embrace the environmental aspects in order to move forward with implementing an EMS. While there are formal definitions floating around, the authors have devised one that helps to integrate cleaner production/pollution revention (CP/P2) more readily into the EMS. An environmental aspect (EA) can be defined as those impacts other than those related to the final product that are created by any unit process, operation, practice, piece of equipment, or feature of a production (manufacturing) operation. The role of the planning stage of an EMS is to identify the negative environmental aspects and then devise ways to eliminate them or minimize the negative impacts. In short, the planning stage of an EMS directs our attention to determining many if not all of the negative EAs. Once EAs and their impacts have been identified, criteria can be applied to rank or prioritize them. This establishes a rational decision-making basis for systematically reducing the negative impacts on a schedule that is consistent with the business goals and longer-term strategies that address such crucial issues as growth and sustainability of the company as a whole. By defining and establishing a priority as to which EAs should be addressed first, based on well-defined criteria, management can then establish goals and targets requirements. This will then allow the company to define environmental action plans for each of the EAs and place them on a schedule for resources and implementation. The process or activity by which EAs are defined is known as an initial environmental review (IER). Examples of how EAs are ranked are provided in the book Green Profits (Cheremisinoff and Bendavid-Val, 2001).

5.4.3

Implementation and operation

As the term implies, this step in the implementation of an EMS is putting the environmental action plans into effect. This step, however, is not just implementing corrective actions or changes that reduce and eliminate EAs, but also embraces programs for training and awareness, establishing avenues for communication inside and outside the organization, maintaining documentation, and planning for operational control and emergency response. Just some of the key issues that will need to be addressed are pollution prevention, continuous improvement, and compliance for reducing identified impacts and the development of managerial programs for achieving them, including a mechanism for identifying applicable legal and other issues that encompass defining roles and responsibilities. 

Checking and corrective action. An organization must measure its performance – against its own targets and objectives, its operational controls, and its compliance with relevant laws and regulations. Specifically, an EMS must define how nonconformance with the ISO standard will be handled and how corrective measures will be taken. But in addition, checking and corrective action is the basis by which continual improvement of environmental performance is achieved. From this standpoint, it is also the basis that renews top management’s commitment to the EMS and further refines the policy and vision of a company. This unto itself is not a simple task

Pollution prevention and best practices for the wood-preserving industry



157

because the larger and more complex an organization is, the more EAs there are to manage. Furthermore, there are cost impacts from actions. And in a practical sense that is what an EMS reduces to – namely, controlling the costs, whether present-day or based on future liabilities, and impacts of environmental management. Senior management must have a clear understanding that P2 and corrective actions from environmental action plans are working not simply to reduce emissions and noncompliance, but are also capturing financial savings, whether it be from reductions achieved in reduced pollution fees or from improved efficiencies, operational performance, energy demand reductions, raw material use savings, improvements to product quality and labor efficiency, and others. Table 5.2 illustrates what many companies often track. Overwhelmingly the category of environmental benefits are tracked and reported by companies that have embraced an EMS. But to business leaders and decision-makers, environmental benefits are most readily understood in terms of dollars. And in fact, for investors, lending institutions, insurance carriers, and partners – it is the dollar savings associated with good environmental performance that are best related to using performance tracking as a means of stewardship when it comes to environmental management. In devising the proper approach to checking and corrective action, the proper metrics need to be defined, and along with the proper metrics, an appropriate environmental management information system (EMIS) must be selected and applied. These terms are discussed further later in this chapter. Management review. To build in continuous improvement, top management must periodically review the system and address necessary changes. This starts the process of continual improvement all over again.

Plan, do, check, and revise are the basic elements of any EMS. Environmental management systems can add significant value for any company, large or small, in a variety of ways. For example, they can:            

provide a cost-effective corporate environmental framework; reduce risks of regulatory noncompliance by systematically tracking applicable requirements; provide a basis for discussing flexibility in regulatory interpretations; help maintain stakeholder confidence by demonstrating reliable environmental protection; provide a basis for self-correction, and mitigating fines and penalties if noncompliance does occur; integrate the principles and cost savings of pollution prevention activities; help sites and programs focus on the most important environmental aspects of their activities; provide an integrating framework for environmental health and safety (ES&H) activities; facilitate deployment of new technologies at sites; provide a basis for ‘‘benchmarking’’ against competitors, within industry sectors and against sector operations; provide vision and stability for staff members and decision-makers in turbulent times; demonstrate responsibility, accountability, and continuous improvement in managing a company’s sites, programs, and assets;

158

 

Handbook of Pollution Prevention and Cleaner Production

bolster investor and public confidence, which can further provide a competitive edge; demonstrate environmental leadership across the private sector.

Implementing an EMS does not alter the basic obligation to comply with applicable requirements or the requirements themselves. Moreover, environmental management systems do not by themselves guarantee effectiveness of the management system itself. Though compliance is already a requirement, an EMS provides ways to make achievement of that end more sustainable For example, an EMS requires a mechanism for systematically identifying applicable legal requirements. An EMS enables a company to focus on improving overall environmental performance by being proactive in the management of its environmental aspects. By being proactive, companies can avoid gaps and lapses in compliance when requirements come into play, and that can curtail future negative impacts from changing and ever-tightening regulations that command greater levels of responsible care. An EMS provides the overall management framework within which the activities will be conducted. Thus an EMS can be used to deploy or amplify the effectiveness of other ES&H initiatives. An EMS can help managers and an entire organization to work smarter, faster, cheaper, and to accomplish more with less. Improved management leads to more efficient and effective performance, and will allow greater control over environmental support costs. A planned comprehensive periodic audit of the EMS is important to ensure that it is effective in operation and is meeting specified goals, and the system continues to perform in accordance with relevant regulations and standards. The audits are designed to provide additional information in order to exercise effective management of the system, providing information on practices that differ from the current procedures or offer an opportunity for improvement. In addition to the audit, there is a requirement for management review of the system to ensure that it is suitable (for the organization and the objectives) and effective in operation. The management review is the ideal forum to make decisions on how to improve for the future. The ISO have developed a series of standards and guidelines in the field of environment that are known collectively as the ISO 14000 series. The various standards and guidelines in the series are listed in Table 5.2. Many North American companies justify the investment in an EMS in order to minimize liabilities associated with noncompliance. Cleaner production/pollution prevention (CP/P2) is a primary driver in achieving the many benefits, including improved compliance. From a more general standpoint, CP/P2 does not just focus on regulated wastes or pollution, but all forms of wastes. In a perfect world 100% of the raw materials, energy, and labor input needed to manufacture a useful product would be transformed into that product. Limitations in hardware, technology, engineering, and human error result in only partial conversion of raw materials and energy into useful products demanded by society. The remainders are by-products and lost energy. Some of the

Pollution prevention and best practices for the wood-preserving industry

159

Table 5.2 Standards and guidelines within the ISO 14000 standards Series

Subject

Standards

ISO 14000

Environmental management systems

ISO 14001 ISO 14004

ISO 14010

Guidelines for environmental auditing

ISO 14010 ISO 14011 ISO 14012

ISO 14020

Environmental labels and declarations

ISO 14020 ISO 14021 ISO 14012

ISO 14030

Evaluating environmental performance

ISO 14031

ISO 14040

Life-cycle analysis

ISO 14040 ISO 14041 ISO 14042 ISO 14043

ISO 14050

Understanding terms and definitions

ISO 14050

byproducts are hazardous while others are not, yet they are still among the waste streams that must be dealt with. All unusable by-products, including lost energy, are forms of pollution. In fact, the terms ‘‘pollution’’ and ‘‘waste’’ as used in this volume are interchangeable. The aim of CP/P2 is to find economical ways to prevent the formation of the by-products, lost energy, and inefficiencies, and to reduce human error and minimize the use of raw materials per unit of production. Clearly the more one is able to reduce ‘‘pollution’’, the more efficient a manufacturing operation becomes, and hence the more profitable the company becomes. By applying CP/P2 practices, technologies, and attitudinal practices among management and employees in managing pollution, the dependence on ‘‘endof-pipe’’ solutions can be reduced or even eliminated altogether. CP/P2 has been applied to raw material extraction, manufacturing, agriculture, fisheries, transportation, tourism, hospitals, energy generation and information systems. Attitudinal changes within an organization are as crucial as the application of the proper CP/P2 technologies and best practices. A change in attitude on the part of company directors, managers, and employees is crucial to gaining the most from CP/P2 programs, and indeed an EMS works most effectively within the context of a proactive ‘‘pollution’’ management scheme. CP/P2 is the application of know-how aimed at improving efficiency, adopting better management techniques, improving housekeeping practices, and refining company policies and procedures. Typically, the application of

160

Handbook of Pollution Prevention and Cleaner Production

technical know-how results in the optimization of existing processes. There are a number of ways in which technical improvements can be achieved:    

by changing manufacturing processes and technology; by changing the nature of process inputs (ingredients, energy sources, recycled water, etc.); by changing the final product or developing alternative products; by on-site reuse of wastes and by-products.

Common types of CP/P2 options include the following:   





Housekeeping improvements to work practices, safety, and proper maintenance can produce significant benefits. These options are typically low cost/no cost. Process optimization improvements. Optimizing existing processes can reduce resource consumption. These options are typically low to medium cost. Raw material substitution. Some environmental problems can be avoided by replacing hazardous materials with more environmentally benign materials. These options may require changes to process equipment. The application of new technologies. Adopting new technologies can reduce resource consumption and minimize waste generation through improved operating efficiencies. These options are often highly capital intensive, but payback periods can be attractive. New product design is an important option. Changing product design can result in benefits throughout the life cycle of the product, including reduced use of hazardous substances, reduced waste disposal, reduced energy consumption, and more efficient production processes. New product design is a long-term strategy and may require new production equipment, pilot testing, plant trials, and marketing efforts.

When a company invests in a CP/P2 program and technologies, they replace end-of-pipe pollution control technologies that add to the costs of production. They also reduce the risks to a company. Any waste that is generated must be dealt with in an environmentally effective manner. Whenever a waste is generated it remains a liability forever. Even if that waste is not regulated at the time it is being generated and the practices and technologies of the day are relied upon, there are no guarantees that it will not become a recognized hazard or regulated waste in the future. The less waste that is generated, the less liability exists for a company. If some of the waste can be recycled or reclaimed, then not only is liability reduced, but some cost recovery may be possible to help pay for the management of the waste. But ideally if one can eliminate or minimize the waste to begin with, then not only will the cost for treatment, transport, and disposal be reduced or eliminated, but the risks or financial exposures to a company are eliminated. This is not only good business sense, but it is most certainly acting in a responsible manner with regard to public safety and the protection of the environment. When CP/P2 options and pollution controls are carefully evaluated and compared, the CP/P2 options are often more cost-effective overall. The initial investment for CP/P2 options and for installing pollution control technologies may be similar, but the ongoing costs of pollution control will generally be greater than

Pollution prevention and best practices for the wood-preserving industry

161

for CP/P2. But in addition, the CP/P2 options will generate savings through reduced costs for raw materials, energy, waste treatment, and regulatory compliance. The environmental benefits of CP/P2 can be translated into market opportunities for ‘‘greener’’ products and ‘‘green label’’. Companies that factor environmental considerations into the design stage of a product are generally well placed to benefit from the marketing advantages of any future ecolabeling schemes. Among the reasons to invest in CP/P2 are:        

improvements to product and processes; savings on raw materials and energy, thus reducing production costs; increased competitiveness through the use of new and improved technologies; reduced concerns over environmental legislation; reduced liability associated with the treatment, storage, and disposal of hazardous wastes; improved health, safety, and morale of employees; improved company image; reduced costs of end-of-pipe solutions.

CP/P2 depends only partly on new or alternative technologies. It can also be achieved through improved management techniques, different work practices, and many other ‘‘soft’’ approaches. CP/P2 is as much about attitudes, approaches, and management as it is about technology. CP/P2 approaches are widely and readily available, and methodologies exist for its application. Because environmental issues are complex, companies are adopting a more systematic approach to environmental management. An EMS provides a company with a decision-making structure and action program to bring CP/P2 into the company’s strategy, management, and day-to-day operations. As EMSs have evolved, a need has arisen to standardize their application. There are a variety of voluntary EMS standards that have been developed by industry groups and consensus standards bodies, the best known of which is ISO 14001. In essence, when an EMS is structured around a dedicated CP/P2 program, a company takes a proactive stance against pollution management. In contrast to companies that react to problems, wastes, and out-of-compliance issues on a case-by-case basis, the combination of an EMS and CP/P2 program identifies causes for waste generation, noncompliance, losses and inefficiencies, and focuses on identifying alternatives to systematically reduce these. We close this chapter and our coverage of the wood-preserving sector with guidance on conducting an initial environmental review (IER). We strongly believe all wood-preserving facilities should conduct such an exercise, whether they have a good perceived environmental track record or not. The primary objective of an IER is to obtain the information necessary to progress the program and implement the EMS, identify early savings, and identify areas of noncompliance and liabilities. This is accomplished by: 

reviewing company policies, aims, and objectives in light of the requirements of the program;

Aspect

162

Table 5.3 Legal and due diligence compliance checklist Check

Permits and/or licences For construction or modification of new or existing sites, facilities, and installations For storm water permit For NPDES permit POTW sewer discharge permits For air emissions permits For title V permits For RCRA permits For hazard communication and right-to-know training Community emergency planning and response For respiratory fit testing program For OSHA programs (e.g. lock-out, tag-out, other) For 40-hour hazwopper training Listing all areas where documentation is incomplete or under development: Due diligence monitoring and reporting Hazard communication training records Pulmonary fit testing for respirators Industrial hygiene and medical monitoring records Spill response and contingency plan documentation

Handbook of Pollution Prevention and Cleaner Production

For underground storage tanks (registrations)

Pollution prevention and best practices for the wood-preserving industry

Preventive maintenance documentation for air pollution controls Preventive maintenance documentations for storm water treatment equipment Preventive maintenance documentation for wastewater treatment Stack testing documentation Industrial hygiene air-quality monitoring Accident reporting records Spill incident reporting records Storm water monitoring records Odor and other complaints records and company responses Plans, lists, photographs Layout plan of the site showing buildings, tanks, open storage facilities, and other significant installations and facilities up to (and including) the site borders. If known, the zones of protected water and the noise sensitivity level of the site and neighborhood should be shown Map of the vicinity (municipal or district level) showing site location and its proximity to towns, rivers, lakes, etc. (approx. scale 1:1000 to 1:5000) General photos, aerial photos of the site Plans of the gas and sewage systems on the site; details on purpose, age, and materials used Plan of tank facilities and storage capacities above ground and underground with features (e.g. with double walls, protective structures) and technical data; date of installation or approval and last check) Waste disposal procedures and/or list of waste and its disposal procedures List of special waste and related disposal procedures Purchasing statistics/inventories of pollutant materials and toxins

163

Continued

164

Table 5.3 Legal and due diligence compliance checklistdcont’d Aspect

Check

Examinations, reports, contracts Environmental impact assessment reports Soil analysis reports, laboratory examinations of the soil of the site and off-site Groundwater monitoring data and well registration Materials flow analyses Wastewater analyses Reports on noise measurements Waste disposal and transporter contracts Copies of correspondence with the authorities, e.g. Environmental Protection Agency Summary reports on incidents Input–output/life-cycle assessments Risk analyses carried out by insurance companies or consultants Copies of incidents recorded by the authorities and others (including those reported internally) Internal procedures Internal safety procedures Internal instructions and guidelines, etc. on pollutants, e.g. CFCs, asbestos, PCBs, others Documentation on procedures to prevent accidents and accident investigations

Handbook of Pollution Prevention and Cleaner Production

Reports on measurements of atmospheric discharges

Pollution prevention and best practices for the wood-preserving industry

  



165

identifying current liabilities or areas of noncompliance and legal requirements that the site or company must comply with; identifying ‘‘early-start’’ initiatives and producing plans for their implementation; reviewing data collection and management arrangements to identify gaps in and produce recommendations for the improvement of data and monitoring management systems; identifying information and data requirements necessary to begin quantifying waste, inefficiencies, losses, and pollution.

Once data have been collected and organized, they can be used to help generate the following:   

a baseline of resource use and environmental performance against which future improvements can be measured; benchmarking the historical/current resource use and environmental performance of the company, site, or processes against typical and good practice; producing an inventory of resource wastage in the company or site, ideally and where appropriate in the form of a complete process map.

The IER guides the rest of the program; hence it is crucial that it is objective and carried out by a person(s) with adequate experience and expertise. An IER provides a broad picture of the environmental aspects within a business’s activities and provides the information by which it can begin planning for corrective actions. The primary aims of such an objective review are to obtain the necessary information to progress the EMS, as well as to identify early savings and areas of noncompliance and liabilities. The checklist (Table 5.3) and audit questionnaires (Boxes 5.1–5.9) included here can be used as a starting basis for identifying key environmental aspects when performing an IER. Readers can modify the questionnaires as appropriate for their facility.

Box 5.1 IER audit questionnaire – Part 1: water 1.1 1. 2. 3. 4. 5. 6. 7. 8.

Consumption Where does the company’s water supply originate? Consider all different sources, e.g. public water supply, groundwater, lakes. How much does your company pay for water per m3? Is the company’s water supply subject to seasonal restrictions due to specific climatic conditions, e.g. drought, flooding? How much water does the company abstract (m3 per year)? Differentiate according to the sources. How much water is consumed (m3 per year)? How is water delivered to the facility? Does the facility monitor the quality of your water supply before it is consumed? Can the facility identify water consumption according to usage, i.e. volume used for processing, cleaning, etc. and the percentage of overall volume which this represents?

Continued

166

Handbook of Pollution Prevention and Cleaner Production

Box 5.1 IER audit questionnaire – Part 1: waterdcont’d 9. 10. 11. 12. 13.

1.2 1. 2. 3.

4. 5. 6. 7. 8. 9. 10. 11.

12. 13. 14. 15.

Is the level of water consumption measured and recorded on a regular basis? Has the facility developed procedures for measuring and recording the volume and quality of water consumed? If so, what are these procedures? What pollutant substances come into contact with water during use, e.g. disinfectants? Have procedures been developed regarding handling of water pollutant substances? If so, what are these procedures? Does the company reuse process water before discharging it? If so: a. what volume of water is reused (m3 per year)? b. what percentage of overall water consumption does this reused water represent? c. what is the water reused for? d. have you identified measures that could be implemented to reduce water consumption? If so, were best practices and clean technologies considered when measures were identified? e. have any of these measures been implemented? If so, what are these measures, and have the results of implementing them been recorded and evaluated to see how effective they are?

Wastewater Does the facility have past records of the volume (m3 per year) and types of wastewater discharged from your site? Can the facility locate all physical points on the site from which wastewater is discharged? What different types of wastewater are discharged from your site? What volume of wastewater is generated by your site (m3 per year)? Differentiate according to the different types. What is the origin of each type of wastewater discharged, e.g. cooling, cleaning? What are the physical, chemical, and biological properties that should be regularly monitored in wastewater? Is wastewater monitored before being discharged? Is the concentration of pollution in wastewater measured and recorded regularly? If so, how often is the concentration of pollution measured? Are the quantities of all pollutant substances detected measured and recorded? What are the different types of methods and devices used for measuring wastewater pollution and quality? Are the devices used by the company to measure wastewater pollution and quality checked on a regular basis to ensure that they are working properly? Have procedures been developed regarding: a. monitoring and measurement of wastewater pollutant content and quality b. recording these measurements c. use and checking of wastewater measurement devices What are these procedures? Where are the different types of wastewater generated discharged to? What is the area of water into which the wastewater is discharged used for, e.g. drinking water supply, agriculture, leisure activities? Have procedures been developed regarding wastewater discharge? If so, what are these procedures? Does the facility monitor the quality of water in the area into which your wastewater is discharged on a regular basis?

Continued

Pollution prevention and best practices for the wood-preserving industry

167

Box 5.1 IER audit questionnaire – Part 1: waterdcont’d 16.

1.3 1. 2. 3. 4.

5.

6. 7.

8. 9. 10.

11. 12. 13.

What measures, if any, have been identified to reduce the amount of wastewater generated by site activities, and reduce and/or eliminate wastewater pollution? a. Which ones were implemented? b. Have the results of implementing them been recorded and evaluated to see how effective they are?

Wastewater management Does the facility have on-site wastewater treatment facilities? If so, what volume is treated (m3 per year) and what percentage of overall wastewater does this represent? What treatment process(es) are used for which type(s) of wastewater? Have procedures been developed regarding internal wastewater treatment? If so, what are these procedures? Is treated wastewater reused in your company? If so: a. how much wastewater is reused (m3 per year) and what percentage of the overall volume of wastewater does this represent? b. what is the treated wastewater used for? c. where is wastewater discharged to once it has been treated? d. does the facility monitor the quality of water in the area into which the treated wastewater is discharged on a regular basis? Does the facility have contracts with external companies to treat or dispose of wastewater? If so: a. do these companies have to meet any environmental requirements? b. what are these requirements? c. where is the water transported to for treatment and disposal? Are on-site treatment facilities regularly checked to ensure that they function properly? Are any wastewaters discharged to a public sewer that is connected to a POTW? If so: a. how much is discharged per year (m3)? b. what pretreatment is done? c. how is the effluent monitored? d. who performs the monitoring? What are the primary wastewaters parameters monitored and controlled to? a. List each effluent parameter and provide ranges of reported/measured values. Is wastewater used for any on-site land application? If so how much per year and for what purpose? Are there any records of accidental water pollution such as spills or unplanned releases to the sewer or land in the past? a. What were the reasons for past accidents? b. What were the environmental and human impacts of past accidents? c. What measures and/or procedures have been introduced to reduce and/or eliminate the risk of such accidents happening again? What would be the impact of an accidental discharge of materials used by the company into its water system or directly into the natural environment? What precautionary measures have been taken in order to isolate wastewater in the case of an accident, e.g. leakage, spillage? What emergency procedures does the facility have in the case of accidental water pollution?

Continued

168

Handbook of Pollution Prevention and Cleaner Production

Box 5.1 IER audit questionnaire – Part 1: waterdcont’d 1.4 1.

2. 3. 4. 5.

Costs and savings Do you know all the costs associated with: a. water consumption, e.g. water charges? b. wastewater discharge? c. internal wastewater treatment, e.g. investment in treatment installations? d. external wastewater treatment, e.g. services provided by external companies? Has the facility identified potential or realized cost savings from reducing or eliminating water consumption, discharge, and/or pollution, e.g. reduced water charges? What are the costs for discharge to the POTW sewer (m3/year)? If on-site treatment or pretreatment is used, does the facility know what it is costing them per m3? Prepare a list of the costs and savings that are already identified.

Box 5.2 IER audit questionnaire – Part 2: soil and groundwater 2.1 1. 2. 3.

4.

5.

6.

7.

Impacts Has a history of operations on the site since they began been compiled in order to determine possible soil and groundwater pollution? Do you know what substances should be monitored in terms of soil and groundwater pollution? Have any analyses of the soil and groundwater been done to check for pollution below and around your site (either by the company or by an external party)? If so, have the results of such analyses been recorded? Has any pollution been detected in the soil and/or groundwater below or around your site? If so: a. do you know when (before or after your activities began on the site) this pollution dates from and how it occurred? b. are soil and groundwater analysed regularly to check for pollution (either internally or by external companies)? c. does the facility know about the different devices for measuring soil and/or groundwater pollution? d. are any devices used by the company to measure soil and/or groundwater pollution checked regularly to ensure they are working properly? Have procedures been developed regarding: a. analysis of the content of soil and/or groundwater? b. recording the results of these analyses? c. use and checking of soil and groundwater pollution measurement devices? If so, what are these procedures? Have all areas on the site where the ground should be made impermeable been identified in order to avoid soil and/or groundwater pollution, e.g. chemical storage areas? If so, have all of these areas been made impermeable? If the facility operates an on-site dump or landfill, have they established a management/ remediation plan for this area once it has reached its full capacity?

Continued

Pollution prevention and best practices for the wood-preserving industry

169

Box 5.2 IER audit questionnaire – Part 2: soil and groundwaterdcont’d 2.2 1. 2. 3. 4. 5.

2.3 1. 2. 3. 4. 5. 6.

2.4 1. 2.

Treatment Has the company already been obliged to remediate or decontaminate polluted soil and/or groundwater underneath or around the site? Have the results of implementing these measures been recorded and evaluated to see how effective they were? What was remediated and how much? Was a formal site closure placed into effect? If so, for what reason? What were the costs of remediation?

Accidental releases Does the facility have records of accidental soil and/or groundwater pollution in the past? What were the reasons for past accidents? What was the environmental and human impact of past accidents? What measures and/or procedures have been introduced to reduce and/or eliminate the risk of such accidents happening again? What emergency procedures do you have in the case of accidental soil or groundwater pollution? Does the facility have a written Spill Response and Prevention Plan?

Costs Do you know the costs associated with preventing soil and/or groundwater pollution and with remediating or decontaminating polluted soil and/or groundwater? Make a list of the costs that you already know about.

Box 5.3 IER audit questionnaire – Part 3: atmospheric emissions and odors 3.1 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Impacts How do the climatic and geographical factors specific to the site influence the atmospheric emissions and odors caused by activities, e.g. exposure to prevailing winds? Does the facility have past records of the types and quantities of emissions/exhausts, and dust generated by their operations? Has an inventory been done of on-site activities that may cause an odor problem? Does the facility know which air pollutant substances should be monitored? Can the facility locate all points from which atmospheric emissions and odors are emitted? Can the facility identify the origin of these emissions, e.g. materials used during processing? What types and quantities of atmospheric emissions are generated by the on-site activities? Differentiate according to the source of emission. What effect do these emissions have on employee health and on the environment and residents in the immediate vicinity of the site? Are the quantities of atmospheric pollutants emitted regularly measured and recorded? Are solvents susceptible of emitting volatile organic compounds (VOCs) used in products and/or in the manufacturing processes?

Continued

170

Handbook of Pollution Prevention and Cleaner Production

Box 5.3 IER audit questionnaire – Part 3: atmospheric emissions and odorsdcont’d 11. 12. 13.

14.

15.

16.

3.2 1.

2. 3. 4.

3.3 1. 2. 3. 4. 5. 6.

3.4 1. 2.

3.

Does the facility know about the different types of devices that can be used to detect air pollutants? Are the devices used to measure atmospheric emissions checked on a regular basis? Have procedures been developed regarding: a. monitoring and measurement of atmospheric emissions? b. recording the results of monitoring and measurements? c. use and checking of atmospheric measurement devices? If so, what are these procedures? How many stacks are there at the facility? a. What air pollution controls are used on each stack? b. Are all permits in place for controls? Which ones are not permitted? c. Has stack testing been performed? When and what are the results? d. Is continuous stack monitoring performed? If so, what is monitored and how? Has the facility identified measures that would reduce and/or eliminate atmospheric emissions and/or odors? If so, were best practices and clean technologies considered when measures were identified? Have any of these measures already been implemented? a. If so, what are these measures and have the results of implementing these measures been recorded and evaluated to see how effective they are?

Treatment Do you have any on-site facilities for treating exhaust air before it is released into the atmosphere, e.g. dust filters? If so, what kind of facilities are used for which kind of emissions? Are each of the controls permitted? What are the dates for permit renewal for each point source control? Do you know about the different types of clean technologies available to treat or reduce air pollution?

Accidental releases Has an inventory been done of accidental atmospheric emissions in the past? What were the reasons for past unplanned releases? What were the environmental and human impacts of past accidents? What measures and/or procedures have been introduced to reduce or eliminate the risk of such accidents happening again? What would be the environmental impact of an accidental release into the air of pollutant substances used in your operations? What emergency procedures do you have in the event of accidental atmospheric pollution?

Costs Do you know the costs associated with reducing and/or eliminating atmospheric emissions, e.g. installation of filters? What are the costs for air permit renewals? a. Are these true costs that include management and labor? b. Can the hidden costs be broken out? Make a list of the costs that the facility already knows about.

Pollution prevention and best practices for the wood-preserving industry

171

Box 5.4 IER audit questionnaire – Part 4: noise and vibrations 4.1 1. 2. 3. 4. 5. 6. 7.

8.

9. 10. 11. 12. 13.

4.2 1. 2. 3. 4. 5. 6.

4.3 1. 2.

Impacts Has an audit been performed identifying the sources and levels of noise and vibrations under normal operating conditions? What are the different sources of noise and vibrations on the site of your activities? Have you had complaints about the noise of your activities from the local residents? If so, what have these complaints been about? Are noise and vibration levels monitored and recorded regularly at the source and at the limits of your site? Do you know about the different types of devices that can be used to measure noise levels and vibrations? Are the devices used by your company to measure noise levels and vibrations checked on a regular basis? Have measures to reduce and/or eliminate noise levels and vibrations been identified, e.g. soundproofing of premises, stopping deliveries at night time? If so, were best practices considered when measures were identified? Have any of these measures already been implemented? If so, what are these measures and have the results of implementing them been recorded and evaluated to see how effective they are? What specific engineering controls are there in place for noise control? What specific managerial tools are in place for noise control? What specific PPE is used for hearing protection of workers? Does the company conduct physical examinations for employees to check for hearing loss? How often? Are results published or accessible to employees? Does the company train employees on hearing loss prevention? Are the training records maintained?

Accidents Do the company have records of accidents that caused the level of noise or vibrations to become unacceptable for employees or local residents? What were the reasons for past accidents? What were the environmental and human impacts of past accidents? What measures and/or procedures have been introduced to ensure that such accidents do not happen again? What emergency procedures do you have if noise or vibrations reach unacceptable levels? Are employees aware of the TWA TLVs?

Costs Does the company know the costs associated with reducing noise and vibration levels, e.g. installation of soundproof walls? Make a list of the costs that you already know about.

172

Handbook of Pollution Prevention and Cleaner Production

Box 5.5 IER audit questionnaire – Part 5: energy 5.1 1. 2. 3. 4.

5. 6. 7.

8. 9.

10. 11.

12.

5.2 1. 2. 3. 4. 5.

5.3 1. 2. 3. 4. 5.

Consumption Are there past records of the amount of energy consumed by activities? Can you identify the points on your site at which energy is consumed? How much energy is consumed by your operations (kWh per year)? What types of and quantities of energy are used by your company? Differentiate between sources, e.g. fuel (m3 per year), gas (kWh per year), renewable and nonrenewable energy, and external supply and own production. How much energy is consumed per unit of production and per employee? What is the level of energy consumption for each source as a percentage of overall energy consumption, e.g. 75% natural gas, 25% electricity? Can you clearly show your energy consumption according to usage, e.g. amount used for processing, heating, etc. and the percentage this represents of overall energy consumption? Is the level of energy consumption measured and recorded on a regular basis? Do you operate heat recovery facilities, e.g. heat recovery from an incineration unit? If so: a. how much heat is recovered? b. what percentage of total consumption does this represent? c. what is the recovered heat used for? Have measures been identified to reduce energy consumption? If so, were best practices and clean technologies considered when these measures were identified? Have any of these measures been implemented? If so, what are these measures and have the results of implementing them been recorded and evaluated to see how effective they are? What are the various fuel sources used to supply energy? Can you develop yearly estimates for each source?

Impacts What atmospheric emissions are generated by your energy consumption, e.g. CO2? Are these emissions measured and recorded on a regular basis? Do you know about the different types of devices that can be used to measure emissions generated by your energy consumption? Are the devices used by your company to measure emissions generated by energy consumption checked on a regular basis? Have any regulatory problems been associated with any sources of energy users? If so, what?

Accidents Do you have a record of any accidents related to your energy facilities, e.g. broken thermostat leading to overheating and explosion of boiler? What were the reasons for past accidents? What were the environmental and human impacts of past accidents? What measures and/or procedures have been introduced to ensure that such accidents do not happen again? What emergency procedures do you have in the case of accidents relating to your energy facilities?

Pollution prevention and best practices for the wood-preserving industry

173

Box 5.5 IER audit questionnaire – Part 5: energydcont’d 5.4 1. 2. 3. 4. 5.

Costs and savings How much does your company pay per year for its energy consumption? Can you trace the changes in energy bills over time, and the reasons for changes? Do you know the costs associated with reducing energy consumption, e.g. installing a new heating system? Have you identified any potential or realized cost savings from energy efficiency? Make a list of the costs and savings that you already know about.

Box 5.6 IER audit questionnaire – Part 6: waste 6.1 1. 2. 3. 4. 5. 6. 7. 8. 9.

10.

11.

6.2 1. 2. 3. 4. 5.

Waste generation Does the company have past records of the amounts and types of waste generated by the operations? What types of waste are currently generated by on-site activities? Is the volume of waste generated measured and recorded regularly? How much solid waste is generated (tonnes per year)? Differentiate according to the types of waste. Can any of the wastes generated by activities be defined as hazardous? If so, which ones and why? Is the facility permitted as a Large Quantity, Small Quantity, or Conditionally Exempt Generator under RCRA legislation (for US facilitites)? How much hazardous waste is generated by the company (tonnes per year)? Differentiate according to the types of waste. What are the sources of the hazardous waste that are generated? Does the facility recycle or reuse any of your wastes internally? If so: a. what quantities and types of waste are reused? b. what percentage of overall waste does this represent? c. what are the waste materials reused for? Have any measures been identified for reducing, eliminating, and/or recycling wastes? If so, were best practices and clean technologies considered when these measures were identified? Have any of these measures been implemented? If so, what are these measures and have the results of implementing them been recorded and evaluated to see how effective they are?

Handling and storage How are the different wastes generated by the facility’s operations collected and stored? Can you clearly identify all points on your site where wastes are collected and stored? Are the contents of the storage containers clearly labeled? Are storage facilities inspected regularly to ensure they are intact and correctly labeled? What procedures have been introduced for collection and storage of the different wastes?

Continued

174

Handbook of Pollution Prevention and Cleaner Production

Box 5.6 IER audit questionnaire – Part 6: wastedcont’d 6. 7. 8. 9. 10. 11. 12.

6.3 1. 2. 3.

4. 5.

6.4 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.

6.5 1. 2.

What procedures and instructions have been introduced for handling hazardous wastes? Are there special storage conditions for hazardous waste before it is disposed of? Does the facility use any kind of electronic waste tracking system to manage stockpiling and disposal of wastes? Are drums stored on pallets? Are there written procedures for managing corroded and leaking drums? How often are waste storage locations inspected for rusted and leaking drums? Are there any air emissions problems associated with on-site waste stockpiles, e.g. airborne dusts?

Treatment Are there any internal treatment or pretreatment facilities for your waste materials? If so, what processes are used? Do you know about the different methods for treating the types of waste generated by your company? Are any materials recovered during treatment or pretreatment? If so: a. which materials are recovered and in what quantities? b. what are these materials used for? Have procedures been introduced regarding treatment of different types of waste? If so, what are these procedures? Does the facility have contracts with external waste treatment companies? If so, do these companies have to meet specific environmental requirements?

Disposal How are the different types of waste sorted before being disposed of or treated? Are there appropriate disposal channels for each type of waste? Where does waste end up once it has left the site of your operations? Are any of the waste materials recycled or reused externally? Do you return any waste directly to the supplier? If so, do you know if the supplier recycles or reuses this waste? Have procedures been introduced regarding disposal of different kinds of waste? If so, what are these procedures? Are records kept of hazardous waste disposal, e.g. consignment tracking numbers? Are hazardous wastes correctly sealed and labeled for transport purposes? Is any treatment or stabilization of wastes practiced? If so, describe them. Are any of the wastes ignitable? Are any of the wastes flammable? Are any of the wastes corrosive? Are any of the wastes toxic? Are any of the wastes classified as forming leachates? Does the facility track waste reduction performance over time?

Accidents Does the facility maintain records of past accidents during waste handling, storage, treatment, or disposal? What were the reasons for past accidents?

Pollution prevention and best practices for the wood-preserving industry

175

Box 5.6 IER audit questionnaire – Part 6: wastedcont’d 3. 4. 5.

6.6

what were the environmental and human impacts of past accidents? what measures and/or procedures have been introduced to ensure that such accidents do not happen again? what emergency procedures do you have in the event of accidents during waste handling, storage, treatment, or disposal?

Costs and savings

1.

Do you know all the costs associated with: a. waste disposal, e.g. collection fees? b. internal waste treatment or pretreatment, e.g. investment in treatment facilities? c. external waste treatment, e.g. fees paid to waste treatment companies? 2. Have you identified any potential or realized cost savings from reducing, eliminating, reusing, and/or recycling of waste, e.g. reduction of waste disposal fees? 3. Make a list of the costs and savings that you already know about.

Box 5.7 IER audit questionnaire – Part 7: raw materials 7.1 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.

Raw and operating materials Are there past inventories of the quantities and types of raw and operating materials used by the facility? What quantities and types of raw and operating materials are currently used? Are records of the cost and origin of these materials maintained? What are the raw and operating materials that you use made up of? Do you have a coding or classification system for the different types of materials? If you use materials that contain hazardous substances, are they clearly labeled? Do you have a register of hazardous materials bought, stored, processed, and transported by your company? What are the environmental impacts of producing your raw and operating materials? Do you have guidelines for purchasing raw and auxiliary materials? If so, what environmental criteria do they include, e.g. buy biodegradable cleaning products? Do suppliers of your materials have to meet specific environmental requirements? If so, what are these requirements? Can you follow the path of hazardous materials used by your company, from the time when they are purchased to when they are discharged from your company as waste? Have you identified measures for reducing and/or eliminating the amount of materials used? If so, what are these measures? Are storage areas for raw and operating materials clearly labeled and equipped depending on the types of materials stored, e.g. with fire protection devices? Is access to storage areas of hazardous materials regulated? Have you already implemented any of these measures? If so, what are these measures, and have the results of implementing them been recorded and evaluated to see how effective they are?

Continued

176

Handbook of Pollution Prevention and Cleaner Production

Box 5.7 IER audit questionnaire – Part 7: raw materialsdcont’d 7.2 1. 2. 3.

7.3 1. 2. 3. 4. 5.

7.4 1. 2.

3.

Semi-finished goods and office supplies Are records of the type, quantity, cost, and source of semi-finished goods and office supplies purchased by the company maintained? Do you have any guidelines for purchasing such goods? If so, what environmental criteria do they include, e.g. always buy recycled paper? Do suppliers of these goods have to meet any environmental requirements? If so, what are these requirements?

Packaging materials What quantities and types of packaging are used during delivery and storage of raw and operating materials, semi-finished goods, and office supplies? Do any of these materials contain any toxic or hazardous substances? Do you apply environmental criteria when deciding which packaging materials to use? If so, what are these criteria? Have you identified any measures for reducing and/or eliminating the amount of packaging used for delivery and storage of materials, semi-finished goods, and office supplies? Have any of these measures already been implemented? If so, what are these measures and have the results of implementing them been recorded and evaluated to see how effective they are?

Costs and savings Do you know the costs associated with reducing and/or eliminating usage of materials, semi-finished goods, and office supplies? Have you identified any potential or realized cost savings from measures to reduce, eliminate, and/or substitute the materials, semi-finished goods, and office supplies that you use? Make a list of the costs and savings that you already know about.

Box 5.8 IER audit questionnaire – Part 8: products 8.1 1. 2. 3.

Design Were any environmental criteria applied during the design of your existing products? If so, what are these criteria? Are environmental criteria applied when new products are designed, e.g. that products should be reusable, recyclable, easily disassembled? If so, what are these criteria? Are employees familiar with or been trained on Design for Environment and/or Life Cycle Tools?

Pollution prevention and best practices for the wood-preserving industry

177

Box 5.8 IER audit questionnaire – Part 8: productsdcont’d 8.2 1. 2. 3. 4. 5. 6.

8.3 1. 2.

8.4 1. 2. 3. 4.

8.5 1.

2.

3.

Packaging Has an inventory been done of the quantities and types of packaging used during storage, packaging, and transport of your finished products? What quantities and types of packaging are currently used for your finished products? Do the packaging materials that you use contain any toxic or hazardous substances? Do you apply any environmental criteria when choosing packaging materials? If so, what are these criteria? What percentage of the packaging used for your products is reusable or recyclable? Can purchasers of your products return the packaging to your company?

Usage Do you know the environmental impacts of your products when the final product is being used? Do you provide customers with information on minimizing environmental impact during usage?

Disposal Where are your products and their packaging disposed of once they have been used? Do you provide users of your products with instructions for disposal? Can users of your products return them to you at the end of their product life? Does your company have the capacity to recycle or reuse all or parts of returned products or their packaging? If so, which parts are reused and for what purposes?

Costs and savings Do you know the costs associated with: a. designing products in order to reduce their environmental impact? b. reducing, eliminating, and/or substituting materials used during manufacture? c. reducing, eliminating, and/or substituting materials used to package your products? d. collecting, recycling, and/or reusing your products at the end of their life? Have you identified potential and/or realized cost savings from: a. designing products in order to reduce their environmental impact? b. reducing, eliminating, and/or substituting materials used during manufacture? c. reducing, eliminating, and/or substituting materials used to package your products? d. collecting, recycling, and/or reusing your products at the end of their life? Make a list of the costs and savings that you already know about.

178

Handbook of Pollution Prevention and Cleaner Production

Box 5.9 IER audit questionnaire – Part 9: logistics 9.1 1. 2. 3. 4. 5.

6.

9.2 1. 2. 3.

Impacts What different types of transport are used by your company, and for what purposes, e.g. heavy vehicles for delivery of raw materials, rail for distribution of finished goods? Do you know the fuel efficiency and emission levels of the vehicles used by your company? If you use external delivery or distribution companies, do you consider the environmental impact of their services? Have you identified measures for reducing the environmental impact of transporting your goods, e.g. using other types of transport, conversion to low-emission vehicles? Have any of these measures been implemented? If so, what are these measures and have the results of implementing them been recorded and evaluated to see how effective they are? Is water used for vehicle washing and maintenance? How much? Are any water-efficient technologies and practices being used?

Costs and savings Do you know the costs associated with reducing or eliminating the environmental impacts of your logistics, e.g. cost of purchasing more fuel-efficient delivery trucks? Have you identified potential and/or realized cost savings from measures to reduce or eliminate the environmental impact of your logistics? Make a list of the costs and savings that you already know about.

References Cheremisinoff, N.P., Bendavid-Val, A., 2001. Green Profits: A Manager’s Handbook to ISO 14001 and Pollution Prevention. Butterworth-Heinemann, Oxford. Cheremisinoff, N.P., Cheremisinoff, P.N., 1984. Hydrodynamics of Gas–Solids Fluidization. Gulf, Houston, TX. National Institute of Occupational Safety and Health (NIOSH), 1977. Criteria for a Recommended Standard: Occupational Exposure to Coal Tar Products. NIOSH, Washington, DC, September. Occupational Safety and Health Administration (OSHA), 1978. Occupational Health Guideline for Coal Tar Pitch Volatiles. OSHA, September. Rezaiyan, J., Cheremisinoff, N.P., 2005. Gasification Technologies: A Primer for Engineers and Scientists. CRC Press, Boca Raton, FL.

6 Sources of air emissions from pulp and paper mills 6.1 Introduction Most of the environmental impact from this industry sector is associated with the manufacturing process (particularly with pulping), with the environmental fate of the product representing a secondary, but still significant concern. Paper products constitute the largest single fraction of municipal solid waste. The US Environmental Protection Agency (EPA) Municipal Solid Waste Factbook (http://www.epa.gov/epawaste/index.htm) notes that paper constitutes about 40% by weight of items discarded in municipal waste nationwide in 1995 before recycling, decreasing to about 32% after recycling. However, the effect of the product is due more to its quantity than to its characteristics, since paper is relatively benign. Manufacturing emissions, on the other hand, pose significant health risks to communities due to both the wide variety of hazardous air and water pollutants and the quantities. Toxics Release Inventory (TRI) data for 1999 (Table 6.1) show the emissions of the paper sector as a whole (SIC code 26) as a percentage of all sectors. The paper manufacturing sector was the third largest contributor of all industry sectors to total reported (TRI) air releases in 1999, behind electric utilities (41%) and the chemicals industry (14%). It was the fourth largest contributor to direct water releases, behind chemicals (30%), primary metals (24%), and food (19%). In terms of overall water use, the EPA Sector Notebook for the sector indicates that ‘‘the pulp and paper industry is the largest industrial process water user in the USA’’. Table 6.1 TRI data showing relative contributions of emissions from the paper industry to all others Releases to: Air Paper indus- 185,968,357 try (lb) All sectors (lb)

Water

Land

Off-site

Total

19,118,393

15,268,270

5,201,498

225,556,518

2,029,364,423 258,881,776 4,746,722,774 462,215,492 7,497,184,465

Paper indu- 9.2 stry (%)

7.4

0.3

Handbook of Pollution Prevention and Cleaner Production Vol. 2 Copyright Ó 2010 by Elsevier Inc. All rights reserved.

1.1

20.9

180

Handbook of Pollution Prevention and Cleaner Production

According to the US Department of Energy, the pulp and paper sector was responsible for 198.8 Tg CO2 equivalent (1 Tg, or teragram ¼ 1 million metric tons). The industry is one of the top five sectors in terms of total greenhouse gas impact (the others being electric power, petroleum refineries, chemicals, and iron and steel mills). This chapter will assist the reader in understanding the major sources of pollution, the chemicals of concern largely from an air pollution standpoint, and methods to estimate some of the releases through the application of emission factors.

6.2 Manufacturing technologies 6.2.1

Wood to paper

The production and use of paper is an enormous industry. Each year, about 300 million metric tons of paper and paperboard are produced worldwide, and the USA alone produces nearly 87 million metric tons per year. Paper is most commonly produced from pulp, which is a dry fibrous material prepared by chemically or mechanically separating fibers from wood. Production of all this pulp and paper requires a large amount of wood. Each year, the world consumes approximately 3.3 billion cubic feet of wood, and about 40% of this is used for paper and paperboard. Paper production requires additional ingredients, including water, sulfur, lime, clay, coal, dye or bleach, and starch. These ingredients are used throughout the pulping process, which will be discussed in this section.

6.2.2

Wood harvesting

To start the process, wood must be harvested from the forest or gathered by recycling. Trees used for pulping are softwood trees (spruce, pine, fir, larch, and hemlock) and hardwoods (eucalyptus, aspen, and birch). Wood is harvested through logging. Logging is the process of cutting down certain trees for timber or forest management purposes. Responsible logging and paper companies use sustainability techniques to ensure ample amounts of the raw materials (wood) needed for paper will be available. Illegal logging, such as clear cutting and timber theft, is a common problem in the industry. Unsafe and irresponsible forest harvesting can lead to the death of valuable and historic forests, a decrease in biodiversity, and legal and financial problems for the company in charge. Most companies, however, follow safe practices and use forests designated for logging. Trees designated for pulp production account for 16% of world pulp production, old growth forests account for 9%, and second- and third- and more generation forests account for the rest (Martin, 2004). Recycled sources of wood are also commonly used to produce pulp. Solid wastes from saw mills are a great source of wood chips and other scraps. These scraps are very cheap alternatives for two reasons: (1) they are waste and can be

Sources of air emissions from pulp and paper mills

181

obtained easily; (2) they are usually free of bark, which eliminates a later step of the process. Pulp mills also use recycled paper for raw materials. This is a very ecofriendly technique, but requires de-inking and other cleaning processes, which can add to production costs.

6.2.3

Cleaning and chipping

Once the wood is harvested, it must be shipped to the pulping plant. This is usually done on trucks (see Figures 6.1 and 6.2). The timber or pulpwood is brought to the plant and stored in piles. Then the wood is sent through the barking drum, where it is stripped of its bark and cleaned. Only sapwood and heartwood are used because bark contains relatively few useful fibers. After debarking, the wood is sent through a chipper to break it into smaller pieces. These chips are screened to ensure consistent size and quality. After chipping, the wood is ready for the pulping process (IFPC, 2009).

6.2.4

Mechanical pulping

There are two main pulping processes: chemical and mechanical. Both processes have the common goal of extracting cellulose from wood by dissolving the lignin that binds the cellulose fibers together. Mechanical pulping is the process in which wood chips are broken down into fibers using mechanical means only. Mechanical pulp was first produced in the mid-nineteenth century by grinding logs against a water-lubricated rotating stone-faced drum. The heat generated by grinding softens the lignin, and the mechanical forces separate the fibers to form ground wood. In the last two decades or so, new mechanical techniques using

Figure 6.1 Logging truck with crane. Source: Premier Alaska Inc., DBA Roland & Company; http://rolandandcompany.com/ 2005_projects/WES/index.html#n

182

Handbook of Pollution Prevention and Cleaner Production

Figure 6.2 Logging Crane Positions Logs for Transport.

refiners have been developed. In a refiner, wood chips are subjected to intensive shearing forces between a rotating steel disk and a fixed plate. Wood chips can also be steamed while being refined in a process called thermomechanical pulping. Steam treatment significantly reduces the total energy needed to make the pulp and decreases the cutting done to the cellulose fibers. Mechanical pulping destroys more of the wood fibers than chemical pulping, which leads to slightly weaker products. Mechanical pulp is often used for newsprint and paperboards. The main benefit of mechanical pulping is that almost all of the wood is used efficiently. Mechanical pulping yields 95% of the wood material used. This high yield efficiency helps keep manufacturing costs low. A negative side of mechanical pulping is that it is not self-sufficient in energy. Mechanical pulping uses approximately 1000 kilowatts per ton of pulp produced (EMT, 2008).

6.2.5

Chemical pulping

Chemical pulping is the other common pulping process. The four principal processes used in chemical pulping are kraft, sulfite, neutral sulfite semi-chemical (NSSC), and soda. The first three have great potential for causing air pollution. The kraft process alone accounts for over 80% of the chemical pulp produced in the USA. The specific process selected for implementation is chosen based on the desired product and wood species available, and by economic factors.

Sources of air emissions from pulp and paper mills

183

The main benefit of chemical pumping is that the pulp fibers produced are long and strong. These long fibers can be used to make much stiffer, stronger paper products. Chemical pulp is used for high-quality white paper and other quality paper products. Another reason why chemical pulping is sometimes preferred is its self-sustainability. The energy created from the combustion of its by-products can generate enough energy to run the whole process. The drawback to chemical pulping is that only 45% of the raw wood put in is returned as pulp. This low efficiency tends to drive up the total cost of production. Table 6.2 shows the benefits and statistics for each process.

6.2.6

Kraft pulping

Kraft pulping is the most common form of chemical pulping, at 80% of the total chemical pulping industry. Kraft pulping involves the digesting of wood chips at elevated temperature and pressure in ‘‘white liquor’’. White liquor is a water solution of sodium sulfide and sodium hydroxide. The lignin that binds the cellulose fibers together in the wood is chemically dissolved by this white liquor. The physical pulping of the wood chips is done in digester systems. Two common types of digester systems are batch and continuous systems. Most kraft pulping is done in batch digesters, although recently, continuous digesters are being installed more commonly. In a batch digester, once cooking is complete, the contents of the digester are moved to an atmospheric tank, usually referred to as a blow tank. The entire contents of the blow tank are sent to pulp washers. The pulp washers separate the pulp from the spent cooking liquor. The pulp then proceeds through various stages of washing and eventually bleaching, which will be discussed later in this section. A benefit of the kraft process is that it is designed to recover the cooking chemicals and heat. Spent cooking liquor and the pulp wash water are combined to form a weak black liquor that is concentrated in a multiple-effect evaporator system to about 55% solids. The black liquor is then further concentrated to about 65% solids. This can be done in a direct-contact evaporator, by bringing the liquor into contact with the flue gases from the recovery furnace, or in an indirect-contact condenser. The strong black liquor is then fired in a recovery Table 6.2 Comparison of pulping processes Mechanical pulp

Chemical pulp

Energy consumption

1000 kW/ton of pulp

Self-sufficient

Percent yield

95

45

Fiber length

Short/broken

Long/intact

Paper strength

Lower

High

Production costs

Lower

Higher than mechanical

Source: EMT (2008).

184

Handbook of Pollution Prevention and Cleaner Production

furnace. Combustion of the organics dissolved in the black liquor provides the energy for the pulping process and for converting sodium sulfate to sodium sulfide. Some mills require more energy than the recovery furnace can provide. These mills use conventional industrial boilers or wood boilers to provide that necessary power. Solid wood wastes are commonly used in these boilers, making chemical pulping plants self-sufficient. Inorganic chemicals present in the black liquor collect as a molten smelt at the bottom of the furnace. This smelt is dissolved in water to form green liquor, which is transferred to a causticizing tank, where quicklime (calcium oxide) is added to convert the solution back to white liquor for return to the digester system. A lime mud precipitates from the tank and it is calcined in a lime kiln to regenerate quicklime. Kraft pulping produces a large amount of pollution. Particulate emissions from the kraft process occur largely from the recovery furnace, lime kiln, and the smelt dissolving tank. These emissions are mainly sodium salts, with some calcium salts from the lime kiln. They are caused mostly by carry-over of solids and sublimation of condensation of the inorganic chemicals. Particulate control is provided in a number of ways (see the sustainability/pollution control section for various control techniques and devices). The chemical emissions of the kraft process are what give pulp mills their distinctive odor. Reduced sulfur compounds, such as hydrogen sulfide, methyl mercaptan, dimethyl sulfide, and dimethyl disulfide, are all constantly emitted by the kraft process. These compounds have a very low odor threshold and can have serious adverse health effects. The major source of hydrogen sulfide is the direct-contact evaporator, in which the sodium sulfide in the black liquor reacts with the carbon dioxide in the furnace exhaust. Methyl mercaptan and dimethyl sulfide are formed in reactions with the wood component, lignin. These compounds are emitted from many points within a mill, but the main sources are the digester/blow tank systems and the direct contact evaporator. Odor and chemical emission control is difficult and will be discussed in a later section (US EPA, 1995b).

6.2.7

Acid sulfite pulping

Acid sulfite pulp is produced similarly to kraft pulp, except different chemicals are used in the cooking liquor. Instead of the caustic solution used to dissolve the lignin in the wood, sulfuric acid is employed. A bisulfate of sodium, magnesium, calcium, or ammonium is used to buffer the cooking solution. The digestion process occurs under high pressure and high temperature, in either batch mode or continuous digesters, and in the presence of a sulfurous acid/bisulfate cooking liquid. When cooking is completed, the contents of the digester are either discharged at high pressure into a blow pit or pumped into a dump tank at a lower pressure. The spent sulfite liquor (red liquor) is then drained through the bottom of the tank. After that it is treated and then discarded, incinerated, or sent to a plant for recovery of heat and chemicals.

Sources of air emissions from pulp and paper mills

185

Due to the variety of cooking liquor bases used, there are numerous schemes for heat and/or chemical recovery. Calcium-based systems, which are usually found in older mills, do not have a practical chemical recovery system and the spent liquor is usually discharged or incinerated. In ammonium base operations, heat can be recovered by combusting the spent liquor, but the ammonium base is thereby consumed. In sodium or magnesium base operations, the heat, sulfur, and base can all feasibly be recovered. If the spent red liquor is recovered, it is concentrated in a multiple-effect evaporator and a direct-contact evaporator to achieve 55–60% solids. This strong liquor is added to a furnace and burned, producing steam to operate the digesters, evaporators, etc. and to meet other power requirements. When magnesium base liquor is burned, magnesium oxide can be recovered from the flue gas combustion produces. This fine white powder, usually collected by cyclones, is then water slaked and used as circulating liquid in a series of venturi scrubbers. When sodium base liquor is burned, the inorganic compounds are recovered as a molten smelt containing sodium sulfide and sodium carbonate. This smelt can be processed further to absorb sulfur dioxide from the flue gas and sulfur burner. Some sodium base mills sell this smelt to kraft mills in order to produce green liquor. Sulfur dioxide is considered the major pollutant of concern from sulfite pulp mills. A major SO2 source is the digester and the blow pit. Sulfur dioxide is present in the intermittent digester relief gases, as well as in the gases given off at the end of the cook when the digester contents are discharged into the blow pit. The amount of sulfur dioxide emitted to the atmosphere from these streams depends on the pH of the cooking liquor, the pressure at which the digester contents are discharged, and the effectiveness of the absorption systems employed for SO2 recovery. Additional sources of sulfur dioxide are the recovery system and the various pulp washing, screening, and cleaning operations (US EPA, 1995b).

6.2.8

Neutral sulfite semi-chemical (NSSC) pulping

During NSSC pulping, wood chips are cooked in a neutral solution of sodium sulfite and sodium carbonate. Lignin in the wood reacts with sulfite ions, and the sodium bicarbonate acts as a buffer to maintain a neutral solution. The major difference between all semi-chemical techniques and those of kraft and acid sulfite processes is that only a portion of the lignin is removed during the cook. The pulping process is completed by mechanical disintegration. This method achieves pulp to wood returns as high as 60–80%, as opposed to 50–55% for all other chemical processes. Some NSSC mills dispose of their spent liquor, some mills recover the cooking chemicals, and some, when operated in conjunction with kraft mills, mix their spent liquor with the kraft liquor as a source of makeup chemicals. When recovery is employed, the steps involved are similar to the sulfite process.

186

Handbook of Pollution Prevention and Cleaner Production

Particulate emissions from NSSC plants are only a concern when recovery systems are involved. A potential gaseous pollutant is sulfur dioxide, and hydrogen sulfide can be produced by NSSC mills that use kraft-type recovery furnaces (US EPA, 1995b).

6.2.9

Soda pulping

Soda pulping was one of the first chemical pulping methods. The main difference between soda pulping and other chemical pulping processes is the makeup of the cooking liquor. Sodium hydroxide is used as the primary cooking chemical for soda pulping. The soda process has limited use for easy pulped materials like straws and some hardwoods, and generally is an outdated technique.

6.2.10 Bleaching After exiting the digester, the pulp/liquor combination is sent through a series of washers and screeners. Eventually the liquor is separated and discharged or recovered, and the pulp is ready for bleaching. Bleaching can be done in a number of different ways. Most methods are compromises between cost, quality, and environmental safety. Mechanical pulps are bleached differently than chemical pulps. Bleaching is a process that reduces lignin, and mechanical pulp contains too much lignin to be practically removed by bleaching. Therefore, the goal of bleaching mechanical pulp (also referred to as brightening) is to remove only the color-causing groups known as chromophores. Alkaline hydrogen peroxide is the most commonly used bleaching agent for mechanical pulp. The amount of base is less than that used in bleaching chemical pulps, and the temperatures involved are lower. These conditions allow alkaline peroxide to selectively oxidize non-aromatic conjugated groups responsible for absorbing visible light. Sodium dithionite is the other main reagent used to bleach mechanical pulps. The brightness gained from bleaching mechanical pulps is temporary. Exposure to air and light can produce new chromophores from residual lignin. This is why newspaper yellows as it ages (Singh, 1979). Chemical pulps contain far less lignin than mechanical pulps. Therefore, the goal of chemical pulp bleaching is to remove essentially all of the residual lignin. Bleaching, or delignification, is rarely a single-step process, and is frequently composed of four or more discrete steps. These steps are given a letter of designation. These letters of designation and their meanings are described in Table 6.3. Bleaching sequences are strings of stages put together. Three common bleaching sequences are: (1) chlorinated – CEHEH; (2) elemental chlorine-free (ECF) – DEDED; or (3) ECF – OXZEPY. In the past, chlorination was the most popular chemical pulp bleaching technique, but it created many environmental and health problems. When elemental chlorine is added to pulp, reactions occur between the chlorine atoms and the lignin. These reactions create chlorinated organic compounds. These

Sources of air emissions from pulp and paper mills

187

Table 6.3 Bleaching stages Symbol

Stage

pH

Temp. (8C)

Description

A

Acid wash

B

Boron hydride, NaBH4

C

Chlorination

2

20–25

Elemental chlorine (Cl2) is added to the pulp. Cl2 is an effective delignifying agent. As it breaks lignin bonds, it adds chlorine atoms to the lignin degradation products, thus producing significant amounts of chlorinated organic material. This organic material can lead to serious environmental hazards, which will be discussed below

D

Chlorine dioxide

3.5–4

60–80

Chlorine dioxide (ClO2) is a highly selective chemical that can both delignify and brighten pulp. It oxidizes lignin, but does not add chlorine atoms on to lignin fragments. This greatly reduces the amount of chlorinated organic material produced

E

Alkaline extraction

12

45–95

The goal of this stage is to remove colored components from partially bleached pulps that have been rendered soluble in dilute warm alkali solutions

F

Formamidine sulfuric acid

H

Sodium hypochlorite

11–11.5

30–60

Sodium hypochlorite (NaOCl) is an inexpensive delignifying agent formed by mixing elemental chlorine with alkali at the mill

M

Chlorine monoxide

N

Nitrogen compounds

Acid wash to remove metals

Continued

188

Handbook of Pollution Prevention and Cleaner Production

Table 6.3 Bleaching stagesdcont’d Symbol

Stage

pH

Temp. (8C)

Description

O

Oxygen

>7

85–95

In the oxygen delignification stage the pulp is treated with oxygen in a pressurized vessel at elevated temperature in an alkaline environment. Oxygen removes lignin and modifies other coloring components

P

Peroxide

65–80

Hydrogen peroxide (H2O2) is mainly used to brighten mechanical and recycled pulps in the final stages of bleaching. Peroxide is used to prevent pulp from losing its brightness over time

Paa

Peracetic acid

Q

Chelatin

Chelatin is added to control the brightness-restricting and reversion effects of iron salts and other heavy metals in the pulp

W

Wash

The pulp is washed to remove reactants from the previous stage

X

Xylanase (enzyme)

Xylanase-based enzymatic pretreatment results in easier bleaching and delignification of the pulp, causing a bleachboosting effect. This is typically used in totally chlorine-free (TCF) pulp

Y

Sodium hydrosulfite

5.5

60–75

Reductive bleaching. Good for recycled pulp

Z

Ozone

2.5

<65

Ozone (O3) is an effective delignifying and brightening agent. Ozone attacks the cellulose fibers as well as the lignin, however

Source: Paper on Web (PW), 2009.

Sources of air emissions from pulp and paper mills

189

compounds build up in the spent liquor, which is burned later in the process. Incomplete combustion of this liquor, and therefore these inorganic compounds, leads to the release of highly toxic and carcinogenic chemicals: dioxins and furans. Since dioxins and furans are toxic and carcinogenic, the use of elemental chlorine as a bleaching and delignifying agent has been regulated. Elemental chlorine-free (ECF) and totally chlorine-free (TCF) pulp production is more common now. ECF pulp uses chlorine dioxide as the bleaching agent. Chlorine dioxide is an effective delignifying agent, and it does not lead to the production of chlorinated organic chemicals. TCF pulp is what it sounds like: pulp created using no chlorine at all. Additional bleaching stages, such as a xylanase stage, are required but quality comparable to chlorinated pulp is produced. Both techniques have shown great reduction in dioxin and furan production (PW, 2009).

6.2.11 Finishing After the pulp has been successfully bleached and delignified, it is dried and ready for shipment to the actual paper production plant. Once there, it is combined with dyes, rosin, alum, clay, and possibly titanium dioxide. After that the pulp is pressed, dried, and turned into a number of different paper products.

6.2.12 Waste reduction/pollution control/sustainability The paper industry is an energy-consuming giant. Worldwide, the paper industry is the fifth largest consumer of energy, accounting for 4% of total global energy use. It also creates waste on a very large scale. It has been estimated that by 2020 paper mills will produce 500 million tons of paper and paperboard per year. Great efforts are needed to ensure that the environment is protected during the production, use, and recycling/disposal of this enormous volume of material. Solid wastes are not the only pollutants that the paper industry must control. Pulp and paper is the third largest industrial polluter to air, water, and land in both Canada and the USA. The industry as a whole releases well over 100 million kg of toxic pollution each year. Both the public and the paper industry know that a sustainable balance, where enough paper is produced and the environment remains unharmed, is necessary in order to keep our way of life intact. In order to achieve sustainability, paper companies are implementing techniques to control waste and emissions. These techniques vary from reducing the overall use of energy to using new technologies to help control emissions. The paper industry understands how important sustainability is. If they destroy the world’s forests then their wood supply will be cut off. Also, consumers demand products that are produced responsibly. Many businesses and personal consumers will not buy paper that is not certified by the Sustainable Forestry Initiative (SFI). The SFI is a nonprofit organization founded by the American Forest and Paper Association to provide a forest certification program.

190

Handbook of Pollution Prevention and Cleaner Production

Additional pressure to reduce waste and emissions comes from agencies such as the EPA. The EPA will penalize a company if its emissions or waste exceeds certain limits. Different mills and plants have different restrictions, but all of them have some sort of regulation. In the future, these restrictions will undoubtedly become stricter. There are many tasks and responsibilities that must be handled in order to achieve sustainability. One major goal of the paper industry today is to completely eliminate the use of elemental chlorine. Chlorine is often used for bleaching the wood pulp, but plants using elemental chlorine produce large amounts of dioxins. Dioxins are some of the most toxic chemicals in the atmosphere, and the uncontrolled release of dioxins is prohibited. In order to reduce the amount of dioxins produced, many pulp mills have switched from chlorine to chlorine dioxide. Plants that do not use elemental chlorine produce elemental chlorine-free (ECF) pulp. Plants that do not use any chlorine-based bleaching techniques create totally chlorine-free (TCF) pulp. ECF and TCF plants release far fewer dioxins than the standard chlorine bleaching plants. In addition, using nonchlorine bleaching agents reduces water pollution in plants’ effluent flows. Due to lack of regulations and consumer demand, only 6% of kraft pulp is bleached without chlorine chemicals. Stricter laws and sanctions need to be implemented in order to convince paper mills to stop using chlorine. Due to the damage that chlorine bleaching inflicts on the environment and human health, the EPA ratified the ‘‘cluster rule’’. The final pulp and paper cluster rule protects human health and the environment by reducing toxic releases to the air and water from US pulp and paper mills. Since the cluster rule has been in effect, all major pulp mills have switched to ECF pulping. Another way paper companies are trying to reach sustainability is by replanting trees. Paper companies devastate forests in order to get the wood supply they need to produce all the necessary paper. In order to make sure that their wood supply does not run out, these companies plant millions of trees a year. Reforestation is not purely beneficial, however. Reforestation is commonly criticized for creating a lack of biodiversity. Paper companies only replant trees that they can use to produce paper, but the forests they destroy involve more than just trees. Shrubs, vines, and bushes are neglected when trees are artificially planted in forests. A careful eye must be kept on reforested areas to make sure that the diversity of the ecosystem is not being damaged by reforestation. Due to the amount of water needed for paper production, a large aspect of sustainability is water resources management. International Paper, a large paper corporation in the USA, used 148 million cubic meters of water in 2006. Paper production requires water for two purposes. Water is used directly in the papermaking process and it is used as a noncontact coolant. The water that is used in the cooling towers is not altered in any way except for a small increase in temperature. The process water, however, will end up with all the waste and pollution from pulping. This water contains a number of different chemicals

Sources of air emissions from pulp and paper mills

191

depending on the specific pulping process. In order to maintain a clean, abundant water supply, effluent water must be treated and returned into the natural waterways. Most modern plants will recycle a lot of their wastewater within the mills themselves. This is a great way to reduce the total water influent and waste at the same time. In fact, International Paper saw a decrease of 2.4% in total water influent and a decrease of 7.1% in total water effluent from 2004 to 2006. Improvements like these are necessary steps towards a safe, sustainable paper industry (International Paper, 2008). Solid waste is another concern for the paper industry. Huge amounts of solid waste are produced every year. International Paper alone sent over one million tons to landfills in 2006. New recycling and reduction techniques are needed in order to achieve a sustainable industry. One way the paper industry is reducing its solid waste is by beneficially applying the waste to the land. This is mainly done by producing fertilizer from the solid waste produced. A rapidly growing technique of solid waste reuse is incineration. Waste materials can be burned to create necessary energy or heat for the paper-making process. International Paper Company reused over 400,000 tons of solid waste through incineration in 2006. This was a 39% increase in the amount burned compared to 2004. This also led to a 10% decrease in the amount of solid waste International Paper sent to the landfill. These improvements are helpful, but landfills are still being filled at an alarming rate. The paper industry has to continuously fight to reduce its solid waste in order to survive in the future (International Paper, 2008). Reducing solid and water waste is important, but it won’t help control chemical and particulate matter emissions. Particulate emissions from the kraft process occur largely from the recovery furnace, the lime kiln, and the smelt dissolving tank. These emissions are mainly sodium salt, with some calcium salts from the lime kiln. They are caused mostly by carry-over of solids and sublimation and condensation of the inorganic chemicals. Particulate control is provided on recovery furnaces in a variety of ways. In mills with either a cyclonic scrubber or cascade evaporator as the direct-contact evaporator, further control is necessary, as these devices are generally only 20– 50% efficient. Most often in these cases, an electrostatic precipitator (ESP) is employed after the direct-contact evaporator, for an overall particulate control efficiency from 85% to >99%. Auxiliary scrubbers may be added at existing mills after a precipitator or venturi scrubber to supplement older and less efficient primary particulate control devices. The following is a discussion on commonly used particulate control devices.

Cyclones Cyclones (see Figure 6.3) are devices used for removing particles from a gas stream by vortex separation. A high-speed rotating flow is established within a cylindrical or conical container. Air flows in a spiral pattern, traveling the length of the cylinder before exiting the cyclone via a straight stream flowing in

192

Handbook of Pollution Prevention and Cleaner Production

PROCESS CYCLONE SCHEMATIC

CLEAN GAS

DIRTY GAS

DUST

Figure 6.3 Simple cyclone. Source: Hutter, G.M., Meridian Engineering and Technology; http://www.meridianeng. com/airpolld.html

the center of the cyclone out of the top. Particles denser than air have too much inertia to follow the tight curve of the stream and strike the side walls. The particles then fall down to the bottom of the cyclone, where they can be removed. Increases in particle density, particle diameter, gas stream velocity, and rotational passes all lead to increased removal efficiencies. The maximum removal efficiency of cyclones is 90%. Limitations include low efficiency for small-diameter particles and high energy costs for volumetric flow requirements, and they are prone to internal corrosion/erosion (Hutter, 1997).

Incinerators An incinerator is a furnace for burning waste. Many paper and pulp mills incorporate them into their pollution mitigation systems. Incineration involves the high-efficiency combustion of certain solid, liquid, or gaseous wastes. The reactions may be self-sustaining based on the combustibility of the waste or require the addition of fuels. They may be batch operations or continuous as with flares used to burn off methane from landfills, and they may incorporate secondary control methods and operate at efficiency levels of 99.99%, as with hazardous waste incinerators. Volume of solid waste can be reduced by up to 95%. Combustion temperatures, contact time, and mass transfer are the major parameters affecting incineration performance. Limitations include high cost of supplementary fuel, high temperatures require good thermal loss control, and

Sources of air emissions from pulp and paper mills

193

INCINERATOR COMPONENTRY CLEAN ODORLESS EFFLUENT

CATALYST PREHEAT ZONE

CONTROL PANEL

BURNER FUMES FROM PROCESS

COMBUSTION AIR BLOWER

FAN

Figure 6.4 Incinerator components. Source: Hutter, G.M., Meridian Engineering and Technology; http://www.meridianeng. com/airpolld.html

hot surfaces, flashback, and explosive conditions (Hutter, 1997). Figure 6.4 shows a schematic of an incinerator.

Catalytic reactors Catalytic reactors (Figure 6.5) can perform similar thermal destruction functions as incinerators, but for selected gases only. They incorporate beds of solid catalytic material that the unwanted gases pass through typically for oxidation or reduction purposes, and have the advantages of lowering the thermal energy requirements and allow small, short-term fluctuations in stoichiometry. Efficiencies of 99.99% are possible with reduced energy costs. Limitations include possible short-circuiting of flow through bed, excessive oxidation and thermal failure, breakthrough of emissions as failure mode, abrasion and thermal shock of catalyst, poisoning of catalyst and drop in performance, and thick beds can cause high pressure drops and increased energy costs.

Wet scrubbers Wet scrubbers are devices that remove pollutants from a gas stream. The goal in absorption and wet scrubbing equipment is the removal of gases and particulate matter from an exhaust steam by causing the gaseous contamination to become

194

Handbook of Pollution Prevention and Cleaner Production

CATALYST BED AND TEMPERATURE PROFILE PRESSURE DROP

CATALYST BED

INLET

OUTLET

X

TEMP

X

Figure 6.5 A catalytic reactor.

dissolved into the liquid stream and the solids to be entrained in the liquid. The rate of gas transfer into the liquid is dependent upon the solubility, mass transfer mechanism, and equilibrium concentration of the gas in solution. Gas collection efficiencies in the range of 99% are possible. Limitations include high pressure drops required, internal plugging and corrosion, increased need for internal inspection, and gas and liquid chemistry control being necessary (Hutter, 1997). One common type of wet scrubber is the venturi scrubber. Venturi scrubbers consist of three sections: a converging section, a throat, and a diverging section. The inlet gas stream enters the converging section and, as the area decreases, gas velocity increases. Liquid is introduced either at the throat or at the entrance to the converging section. The inlet gas, forced to move at extremely high velocities in the small throat section, shears the liquid from its walls, producing an enormous number of tiny droplets. Particle and gas removal occur in the throat section as the inlet gas stream mixes with the fog of tiny liquid droplets. The inlet stream then exits through the diverging section, where it is forced to slow down (Brady and Legatski, 1977). Figure 6.6 shows a venturi scrubber.

Direct-contact evaporators Direct-contact evaporators are devices in which the liquid phase is vaporized by injection of a superheated gas. The superheated gas is injected into the liquid

Sources of air emissions from pulp and paper mills

195

Liquid inlet

Liquid inlet

Throat

Figure 6.6 Venturi scrubber. Source: Wikipedia.org, ‘‘Venturi Scrubber’’, 2009; http://en.wikipedia.org/wiki/Venturi_ scrubber

phase through submerged orifices of a distribution system. The gas forms bubbles that grow at the orifices until reaching a critical volume, at which point they detach (Kumar and Kuloor, 1970). After the formation stage, the bubbles ascend in the liquid column. The vapor is then removed from the system by the bubbles that reach the top of the liquid column (see Figure 6.7). Drawbacks include high energy costs and relatively low removal efficiencies.

Baghouses Baghouses (Figure 6.8), also known as fabric filters, use filtration to separate dust particulates from dusty gases. Dust-laden gases enter the baghouse and pass through fabric bags that act as filters. The bags can be of woven or felted cotton, synthetic, or glass-fiber material in either a tube or envelope shape. They are one of the most efficient and cost-effective types of dust collectors available and can achieve a collection efficiency of more than 99% for very fine particulates. This high efficiency is due to the dust cake formed on the surfaces of the bags. The filter cake is removed to hoppers by various shaking means. Limitations include plugging, short-circuiting, breakthrough, collection media fouling,

196

Handbook of Pollution Prevention and Cleaner Production

mg, xg

mv + m g, xv Tv

Tg dt Qv dc

Tvn

Tgn ms, Y, TL Qb

Qd H h

me, Ye, Te mL, Y, TL Tgd

Qp Tgb

Figure 6.7 Direct-contact evaporator. Source: Campos and Lage (2001).

SINGLE BAG SCHEMATIC EXHAUST

ΔP

REPRESSURING VALVE FILTERING MODE COLLECTION HOPPER

COLLAPSING (BAG CLEANING MODE)

Figure 6.8 Baghouses. Source: Hutter, G.M., Meridian Engineering and Technology; http://www.meridianeng. com/airpolld.html

Sources of air emissions from pulp and paper mills

197

accumulation of flammable gases and dusts, and unexpected bag failure due to changes in operating procedures (Hutter, 1997).

Electrostatic precipitators Electrostatic precipitators (ESPs; Figure 6.9), or electrostatic air cleaners, are particulate collection devices that remove particles from a flowing gas (such as air) using the force of an induced electrostatic charge. To produce the free ions and electric field, high internal voltages are required. ESPs are highly efficient filtration devices that minimally impede the flow of gases through the device, and can easily remove fine particles, such as dust and smoke, from the air stream. In contrast to wet scrubbers, which apply energy directly to the flowing fluid medium, an ESP applies energy only to the particulate matter being collected and is very efficient in its consumption of energy. Limitations include the large installation space required, high potential for ignition sources, and susceptibility to changes in moisture and resistivity (IUPAC, 2009).

Adsorption The process of adsorption involves the molecular attraction of gas-phase materials on to the surface of certain solids. This attraction may be chemical or physical in nature and is predominantly a surface effect. Certain materials like activated carbon charcoal possess a large internal surface area and the presence of physical attraction forces to adsorb large quantities of certain gases within their structure. The rate of adsorption is affected by the temperature,

Figure 6.9 Electrostatic precipitator. Source: Arizona State University, Electrical Engineering Department. ‘‘Electrical Engineering for Pollution Control’’, January 2003; http://www.eas.asu.edu/~holbert/ wise/electrostaticprecip.html

198

Handbook of Pollution Prevention and Cleaner Production

concentration, atmospheric pressure, and molecular structure of the gas. Limitations include the possible requirement of multiple units, flammable hydrocarbons, and chemical mixture problems (Hutter, 1997).

Odor control The pulping process uses sulfur compounds to break wood down into pulp. Some of these sulfur compounds escape the process and are released into the atmosphere. Sulfur compounds, such as hydrogen sulfide, dimethyl sulfide, and dimethyl disulfide, are famous for their pungent odor and very low odor thresholds. Pulp and paper mills usually do not have odor control devices, but emitted sulfur compounds can be reduced by process modifications and improved operating conditions. For example, black liquor oxidation systems, which oxidize sulfites into less reactive thiosulfates, can considerably reduce odorous sulfur emissions from the direct-contact evaporator, although the vent gases from such systems become minor odor sources themselves. Also, noncondensable odorous gases vented from the digester/blow tank system and multiple effect evaporators can be destroyed by thermal oxidation, usually by passing them through the lime kiln. Efficient operation of the recovery furnace, by avoiding overloading and maintaining sufficient oxygen, residence time, and turbulence, significantly reduces emissions of reduced sulfur compounds from this source as well. The use of freshwater instead of contaminated condensates in the scrubbers and pulp washers further reduces odorous emissions (US EPA, 1995b). Several new mills have incorporated recovery systems that eliminate conventional direct-contact evaporators. In one system, heated combustion air, rather than fuel gas, provides direct-contact evaporation. In another, the multiple-effect evaporator system is extended to replace the direct-contact evaporator altogether. In both systems, sulfur emissions from the recovery furnace/directcontact evaporator can be reduced by more than 99% (US EPA, 1995b). Controlling emissions is a vital part of a sustainable industry. Irresponsible pollution, especially of odorous chemicals, can damage the environment and the people who live in it. The EPA does its part to ensure safe breathing environments surrounding pulp and paper mills, but the leaders of the corporations have to do their part too. Companies usually do what is best economically and not what is best morally or socially. If an emission control initiative will negatively affect a company’s stock market value, the initiative will probably not go through. Therefore, it is important that the EPA and other government agencies continue to put pressure on all manufacturing plants to keep lowering emissions and waste every year. A good way to encourage ecoresponsibility is giving bonuses to plants that meet and exceed certain emission standards, and giving penalties to plants that do not perform well. Without these incentives, corporations will not go out of their way to improve emissions reduction, and the environment will continue to worsen (US EPA, 1995b).

Sources of air emissions from pulp and paper mills

199

6.3 Chemicals of concern and pollution sources 6.3.1

General information on pollution sources

The following provides a concise summary of the principal chemicals of concern and the sources of air emissions:  

 







Ammonia. Sources are digesters and the secondary treatment plant. This chemical is a concern because it is a precursor of fine particulate formation and it is an irritant. Carbon monoxide. Sources are the lime kiln and power boilers. This chemical is a concern because there is human visual impact at 50 ppm for 1 hour, death at more than 750 ppm, and vegetation impact at higher levels. Carbon dioxide. Sources are the effluent treatment system and power boilers. This chemical is a concern because it is a greenhouse gas. Carbonyl sulfide. The primary source is the recovery boiler. This chemical is a concern because it is a potential neurotoxin; acute (short-term) inhalation of high concentrations of carbonyl sulfide may cause narcotic effects in humans. Carbonyl sulfide may also irritate the eyes and skin in humans. Chlorine and chlorine dioxide. Sources are generation systems, extraction stage scrubbers, and bleach plant ‘‘upsets’’ such as explosions. Chlorine is present in almost all areas of a mill, including wood yards at facilities that rely on chlorine dioxide bleaching. Chlorine dioxide breaks down to release chlorine into the air and from the pulp. Chlorine and chlorine dioxide exposures can cause significant short-term peaks that exceed regulatory limits, and pose a health risk. Chlorine is a severe short- and long-term respiratory irritant at levels above 1 ppm (odor threshold 60–200 ppb); chlorine dioxide is a severe short- and long-term respiratory irritant at levels above 0.1 ppm (odor threshold 100 ppb; NIOSH, 1987). Both compounds kill at high levels. The characteristic response to short-term chlorine and chlorine dioxide exposure is reactive airway dysfunction syndrome (RADS), airway inflammation, and bronchial hyper-responsiveness, which may last for 3 years or more, and can result from one acute exposure. Adverse effects on immune system, blood, heart, and respiratory system have been reported from numerous reports in laboratory studies. Chloroform. Sources are the effluent treatment system and bleach plant. This chemical is a recognized carcinogen, suspected respiratory, cardiovascular or blood, liver and kidney toxicant, and endocrine and neurological disruptor. Dioxins and furans. Sources are the recovery boiler and the power boiler if burning ‘‘salty’’ hog fuel. Health effects associated with dioxins and the chemically similar polychlorinated biphenyls (PCBs), probably through action on the chemical messengers of the body, and passed on through the generations, include: reproductive effects, from low sperm count to endometriosis; hyperactivity; allergies and immune and endocrine system malfunctions; diabetes; low birth weight, poor motor coordination and lower IQ for children. Dioxins are classified as a human carcinogen by the International Agency for Research on Cancer (IARC) and they are recognized as tumor promoters, along with their other roles in modifying and disrupting growth functions. Adverse health effects include skin disease, immunosuppression, respiratory effects, cardiovascular effects, liver effects, reproductive toxicity, and they have a Carcinogenicity 2B rating.

200















Handbook of Pollution Prevention and Cleaner Production

Hydrogen chloride (part of particulate matter). The primary source is the recovery boiler. This chemical is a concern because it is a suspected gastrointestinal or liver toxicant, and respiratory and skin or sense organ toxicant. Methanol. Sources are the recovery boiler, oxygen delignification systems, and the effluent treatment system. Methanol has been accepted by the US EPA as a surrogate monitoring measurement for a wide range of the hazardous air pollutants (chlorinated compounds) that the USA requires polluters to report, and the US cluster rules now require mills to collect these gases and burn them in the fire zone of the recovery boiler. Methanol is a concern because it is a suspected developmental toxicant, neurotoxin, gastrointestinal or liver toxicant. Nitrogen oxides (NOx). Sources are the lime kiln, recovery boiler, power boiler, gas turbines, and brown stock washers. NO2 is an acute respiratory irritant at 1 ppm for 15 minutes. It is a harmful air contaminant, a precursor to smog, ground-level ozone, fine particulates, and acid rain. It is harmful to humans, vegetation growth, and health. Particulate matter (PM). Sources are the recovery boiler, lime kiln, smelt dissolving tank, power boilers, wood chip yard, and dust from landfills. PM can be material, such as wood, lime, or road dust, or chemical compounds created with carbon, metallic oxides and salts, acids, oils, etc. The greatest health impact is felt from particles of the smallest size – designated PM10 (microns) or less, and especially PM2.5 – which penetrate the lungs and stay there, frequently delivering a toxic load to the body. Fine particulates are linked to serious health impacts, including chronic bronchitis, asthma, and premature deaths. PM2.5 has been recognized to have the potential for the greatest health impact on a larger segment of the general public. Secondary particles are formed through chemical reactions involving the precursors NOx, volatile organic compounds (VOCs), sulfur oxides (SOx), and ammonia (NH3). The US Federal standard is 150 mg/m3; health impacts include children’s absenteeism due to asthma at 50 mg/m3. British Columbia has set a new air-quality objective of 25 mg/m3 for PM2.5; the Canadian Council of Ministers of Environment have determined a Canada Wide Standard for PM, focused on the fine fraction of PM, smaller than 2.5 microns, known as PM2.5, of 30 mg/m3 averaged over 24 hours, on be achieved by 2010. Phenols. Sources are power boilers, brown stock washers, chip bins, and the effluent treatment system. This chemical is a concern because it is a smog precursor, it kills fish, it is toxic on kidneys of humans, and it has a wide range of sensitive effects, including on blood, immune and nervous systems. Sulfur oxides (SO2, SO3, and solid sulfates). Sources are the recovery boiler, lime kiln, power boilers, brown stock washers, and chip bins. Anywhere sulfur-containing compounds, including oil and gas, are burned, there will be sulfur oxide emissions. These chemicals are irritating to eyes and respiratory system at 5 ppm for 10 minutes. SOx is a precursor to fine PM formation. Sulfuric acid is implicated in bronchitis, emphysema, eye, nose, and stomach irritations, and possible lung cancer in exposed workers. Total reduced sulfur compounds (including hydrogen sulfide, methyl mercaptan, dimethyl sulfide, and dimethyl disulfide). The primary source of these chemicals is the recovery boiler. These chemicals are associated with an extraordinary foul smell. They are toxic and heavier than air, thus traveling long distances to ground level. H2S irritates eyes at 50 ppm and causes death at 100 ppm. The human nose detects H2S at about 1 ppb.

Sources of air emissions from pulp and paper mills



201

Miscellaneous. Miscellaneous chemicals that are emitted as air pollution include alcohols, terpenes, acetaldehyde, nitrates, fungi (Aspergillus fumigatus and A. versicolor), bioaerosols (endotoxin), benzene and assorted substituted benzenes, chlorinated benzenes and phenolics, guaiacols, and various VOCs, many of them unquantified and unidentified, but including dichloroacetic acid methyl ester, 2,5dichlorothiophane, styrene, toluene and xylenes, all varying from day to day, depending on feed stock and ‘‘upsets’’ anywhere in the mill. The EPA has noted under the Clean Air Act that emissions from pulp and paper derive from chemicals used or by-products, and include alcohols, aldehydes, benzene, ketones, polyaromatic hydrocarbons (PAHs), and phenolics. All of these chemicals are associated with heart disease.

In addition to air emissions there are also solid wastes and significant liquid effluents, which include pulping liquors and bleaching effluents. Bleaching effluents contain chlorinated dioxins and furans, chloroform, and various other chlorinated compounds. The impact of the pulp and paper sector on greenhouse gas emissions is complicated, as atmospheric carbon dioxide is the ultimate carbon source for the sector’s product. Arguments have been made that as long as the carbon is sequestered in paper, it is not contributing to global warming. This viewpoint allows us to subtract a portion of the total greenhouse gas emissions attributable to the sector (primarily due to its energy consumption) to account for the carbon removed from the atmosphere. We actually like this argument within the context of durable products like construction materials, which have an expected lifetime measurable in decades. We may make the same argument for products like certain packaging materials made from plastics derived from renewable sources that are used as an alternative to plastics derived from fossil fuels. But in the case of paper products much of the output of the sector is returned to the atmosphere after a relatively short period of time. The products are either burned or deposited in landfills where they decompose biologically. Within the context of a normal life-cycle assessment, we find this argument to be frivolous. The National Emission Trends (NET) database reports air emissions data for certain key criteria pollutants (ozone precursors). Hazardous air pollutant emissions data are available from the TRI. For the pulp and paper sector, the total emissions are, to say the least, impressive. For criteria pollutants, 1999 reporting shows the following criteria pollutants:    

VOCs – 201,318 tons per year; nitrogen oxides (NOx) – 325,958 tons per year; fine particles, under 2.5 microns (PM2.5) – 65,237 tons per year; hazardous air pollutants (HAPs) – 23,952 tons per year.

For VOCs, the pulp and paper sector is the second highest emitter of all manufacturing sectors, second only to commodity chemicals. For NOx, pulp and paper is the fourth highest, behind electric power, oil and gas extraction, and commodity chemicals. For fine particles, it is second only to electric power. For HAPs, it stands fifth, behind commodity chemicals, construction, petroleum refining, and furniture.

202

Handbook of Pollution Prevention and Cleaner Production

As impressive as these figures are, they are dwarfed compared to those of two to three decades earlier. We can get a sense of this from the the American Forest and Paper Association (AF&PA) Progress Report of December 2002 (http:// www.afandpa.org/) in which the AF&PA lists a number of industry benchmarks, based on 1999 data from its members. Among the benchmarks listed for pulp and paper mills are: 





Water quality:  wastewater generation rate – 12,600 gallons per ton of production (a 44% reduction since 1975);  biological oxygen demand (BOD) – 2.9 pounds per ton of production (an 84% decrease since 1975);  total suspended solids (TSS) – 4.2 pounds per ton of production (a 68% decrease since 1975);  adsorbable organic halides (AOX) – less than 0.4 kilograms per metric ton of chemically bleached pulp (a 90% decrease since 1975). Air quality:  sulfur dioxide (SO2) – 9 pounds per ton of production (a 65% decrease since 1980);  nitrogen oxides (NOx) – 6 pounds per ton of production (a 23% decrease since 1980);  total reduced sulfur (TRS) – 0.9 pounds per ton of kraft pulp production. Solid waste (nonhazardous) generation rate – 287 pounds per ton of product (excluding wood wastes that include a number of persistent and bioaccumulative toxins (such as chlorinated dioxins and furans) that can impact the food chain, and can collect in sediments).

6.3.2

Chemical exposure and toxicological profiles of chemicals

The paper and allied products industry (SIC 26) can be broken down into two categories: pulp and paper mills that process raw wood fiber or recycled fiber to make pulp and/or paper, and converting facilities that use these primary materials to manufacture more specialized products such as paperboard boxes, writing paper, and sanitary paper. Pulp mills separate the fibers of wood or other materials, such as rags, linters, wastepaper, and straw, in order to create pulp. These mills commonly use chemical, semi-chemical, or mechanical processes in the creation of pulp and may create toxic co-products such as turpentine and tall oil. Paper mills primarily are engaged in manufacturing paper from wood pulp and pulp derived from other fibers. Most of the chemical emissions of the paper industry come from chemical wood pulping. Chemical wood pulping involves the extraction of cellulose from wood by dissolving the lignin that binds the cellulose fibers together. The four processes principally used in chemical pulping are kraft, sulfite, neutral sulfite semi-chemical, and soda. The first three of these display the greatest potential for causing air pollution. The kraft process alone accounts for over 80% of the chemical pulp produced in the USA. The choice of pulping process depends on

Sources of air emissions from pulp and paper mills

203

the desired product, wood species available, and economic considerations. Each process has a specific set of emissions. The kraft process is the digesting of wood chips at elevated temperature and pressure in ‘‘white liquor’’, which is an aqueous solution of sodium sulfide and sodium hydroxide. This process emits a wide variety of particulate matter and chemicals. Particulate emissions from the kraft process occur largely from the recovery furnace, lime kiln, and smelt dissolving tank. These emissions are mainly sodium salts, with some calcium salts. To control these particles a directcontact evaporator and an electrostatic precipitator (ESP) are used for overall removal efficiency between 85% and 99%. Kraft pulping also releases a lot of chemical emissions. Since the process is done in sodium sulfide solution, many of the chemicals released contain sulfur. Examples include hydrogen sulfide, sulfur dioxide, dimethyl sulfide, and dimethyl disulfide. These compounds are the major source of kraft mill odor emissions, and they can be detected easily due to their very low odor thresholds. Even though these kraft mills produce very odorous emissions, very few of them have odor-controlling devices. Not all kraft mill emissions are sulfur based. Some of the major chemicals that are released are methanol, ammonia, carbon monoxide, formaldehyde, phenol, hydrochloric acid, and sulfuric acid. Many of these pollutants are produced by side processes including steam power production. Most of the chemicals emitted are on the EPA’s hazardous air pollutants list, and they need to be monitored and controlled at the highest level possible. The EPA pays attention to and regulates these chemicals due to their individual health and environmental effects. This chapter describes each chemical, how they are produced and released, how humans and animals can be exposed, and what effects exposure can lead to (US EPA 1995b). The following chemicals are discussed:                  

Acetaldehyde Acrylonitrile Ammonia Benzene Chlorine disulfide Chlorine Chloroform Chromium(VI) Dioxin Ethylene glycol Formaldehyde Formic acid Hydrochloric acid Hydrogen fluoride Hydrogen sulfide Methanol Methyl mercaptan Pentachlorophenol

204

   

Handbook of Pollution Prevention and Cleaner Production

Phenol Sulfuric acid Sulfur dioxide Toluene.

Acetaldehyde Acetaldehyde (CASRN 75-07-0) is a VOC with the formula CH3CHO. It is a flammable, colorless liquid with a pungent, fruity odor. Green plants produce it as they break down their food, and it is also found naturally in ripe fruit, coffee, and bread. It is produced in large amounts (740 million pounds in 1989) by two companies in the USA. Acetaldehyde is most commonly used as an intermediate in the chemical production of acetic acid and other chemicals. Humans can be exposed to acetaldehyde in the workplace or in the environment following a release into air, water, soil, or groundwater. Eating ripe fruit, drinking coffee, and smoking a cigarette can also expose humans or animals to acetaldehyde. Once released into air, acetaldehyde immediately evaporates and disperses. It does not cause direct harm to the atmospheric environment by itself, but can contribute to the formation of photochemical smog in the presence of other VOCs. Acetaldehyde does not bind well with soil, so most of the underground contamination occurs in groundwater. The EPA has declared that acetaldehyde is a hazardous air pollutant (HAP). Health effects on humans and animals depend on the concentration and time of exposure. The health of the person or animal exposed, as well as the conditions of the environment, can also influence the effects of exposure. Acute inhalation exposure (25–200 ppm for 15–30 minutes) to humans can cause irritation of the eyes and respiratory tract, as well as altered respiratory function. Animals such as rats, exposed to acute inhalation of higher concentrations, showed skin and eye irritation and notable cellular alterations in the respiratory epithelium and hyperkeratosis of the forestomach (Appleman et al., 1986). Also, acute toxicity to aquatic life has been observed in concentrations in the range of 1– 100 mg/l. Human health effects associated with the chronic exposure to acetaldehyde are unknown. Evidence collected through animal studies show that exposure to acetaldehyde over long periods of time has numerous adverse effects. Rats exposed to 2200 or 5000 ppm for 6 hours per day, 5 days per week for 4 weeks experienced death, decreased organ weight, growth retardation, and severely damaged respiratory tracts. Animal studies also showed that long-term exposure to acetaldehyde caused an increase in nasal tumors. These and similar studies led the EPA to declare that acetaldehyde is a class B2, probable human carcinogen. The EPA also determined the reference concentration (RfC), the lethal dose (LD50) and lethal concentration (LC50), the least-observed-adverse-effect level (LOAEL), the no-observed-adverse-effect level (NOAEL), and the permitted exposure limit (PEL) (US EPA, 1991a). The values for these properties can be found in Table 6.4.

Sources of air emissions from pulp and paper mills

205

Table 6.4 Toxicological characterization data for acetaldehyde RfC

LD50 (rats)

LC50 (rats)

LOAEL

NOAEL

PEL

0.009 mg/m3

1.93 g/kg

36 g/m3 (30 min)

720 mg/m3

702 mg/m3

360 mg/m3

Source: US EPA (1991a).

The reference dose (Rfd) and reference concentration (RfC) are estimates (with uncertainty spanning perhaps an order of magnitude) of an applied dose or continuous inhalation exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. The LD50 and LC50 are the dose and concentration, respectively, required to kill at least 50% of the tested sample. The LC50 usually requires a given exposure time. The LOAED is the lowest concentration or dose that had an effect in a given trial, and the NOAEL is the highest concentration or dose where no effect is observed in a given trial. The permitted exposure limit is a concentration ceiling that cannot be exceeded in any occupational workplace.

Acrylonitrile Acrylonitrile (CASRN 107-13-1), also known as AN or vinyl cyanide, is a manmade VOC. It is a pungent smelling, colorless flammable liquid with the chemical formula CH2CHCN. Its vapors are highly flammable and can explode when exposed to an open flame. Five companies produce AN in the USA, and they produced a total of 2.5 billion pounds in 1993. AN is most commonly used to make acrylic and modacrylic fibers, but can also be used to produce highimpact plastics, packaging plastics, adiponitrile (a chemical involved in the production of nylon), dyes, drugs, and pesticides. Exposure to AN may occur in the environment following releases to air, water, soil, and groundwater. Humans can also be exposed to AN in the workplace, by smoking a cigarette, or by breathing automobile exhaust. AN can also be absorbed through skin contact. It is not likely to be stored in plants and animals, however, due to easy breakdown and removal. AN evaporates when exposed to air and dissolves in water. Once dissolved in water, AN has relatively slow evaporation and biodegration rates. AN can stay dissolved in water for 6–20 days. There is no evidence that AN directly harms the atmospheric environment, but it reacts with other VOCs to produce photochemical smog. The EPA has declared AN an air toxic. Health effects on humans and animals depend on the concentration and time of exposure. The health of the person or animal exposed, as well as the conditions of the environment, can also influence the effects of exposure. The symptoms of acute toxicity for AN resemble those of cyanide, which can adversely affect the nervous system, the blood, the kidneys, and the liver. There have been many instances of child mortality due to exposure to AN vapors, whereas adults experienced only mild symptoms when exposed to

206

Handbook of Pollution Prevention and Cleaner Production

the same environment. Prior to death, these children experienced respiratory malfunction, lip cyanosis, and tachycardia. Workers in a rubber manufacturing plant experienced irritation of the mucous membranes, nausea, headaches, and nervous irritability after being exposed to 15–100 ppm for 20–45 minutes. These symptoms abated when exposure ceased (Wilson et al., 1948). AN is also toxic to most aquatic species exposed acutely. A study done on snails showed a 100% mortality rate in a concentration of 0.24 mg/l for 24 hours. The results of studies in humans with long-term exposure to AN have been either negative or inconclusive for noncancer chronic effects. Studies on animals, however, have shown different results. Animals such as rats, rabbits, and monkeys showed signs of toxicity when exposed to concentrations of 50–200 ppm for 8 weeks. Their symptoms included irritation of the eyes and nose, gastrointestinal disturbances, and weakness of the hind legs. The animals recovered after exposure ceased. Cats and dogs showed even higher toxicity, including death, at the same concentration levels (Dudley et al., 1942). Also, exposure to pregnant animals orally or by inhalation showed signs of developmental toxicity, including malformations in fetuses. Table 6.5 shows values for significant properties of AN. Exposure to AN has been associated with cancer in humans. The EPA classifies AN as a B1, probable human carcinogen. This was based on a study that followed 1345 textile workers who were exposed to 5–20 ppm acrylonitrile. In 10 years of follow-up, there were 25 cases of cancer, and five of those cases were respiratory cancer. The expected number of respiratory cancer cases for that sample was 1.6 (O’Berg, 1980). This significant difference between expected and observed instances proved to the EPA that AN was indeed a carcinogen. Further laboratory experiments show that AN is also carcinogenic to animals (US EPA, 1991b).

Ammonia Ammonia (CASRN 7664-41-7) is another harmful chemical released by the paper industry. Ammonia, a.k.a. anhydrous ammonia, has a pungent odor and is usually found in gas form due to its boiling point of 33 C. The most common use of ammonia is the production of fertilizer: 83% of all ammonia is used in fertilizers. Ammonia is also commonly seen in household cleaning products in the form of ammonium hydroxide, which is simply ammonia dissolved in water. Producing the necessary amount of ammonia for the modern world is not an easy task, and it represents 1% of the world energy budget. Table 6.5 Toxicological characterization data for acrylonitrile RfC

LD50 (rats)

LC50 (rats)

LOAEL

NOAEL

PEL

0.002 mg/m3

93 mg/kg

470 mg/m3 (4 h)

43 mg/m3

10 mg/kg/day

4.3 mg/m3

Source: US EPA (1991b).

Sources of air emissions from pulp and paper mills

207

Ammonia can be released into the environment into air, water, soil, and groundwater. The most common releases of ammonia are effluent discharges from industrial processes and run-off from fertilized fields. Humans can be exposed to the hazards of ammonia through ingestion of contaminated food or water, inhalation or skin contact. The EPA has classified anhydrous ammonia as an extremely hazardous substance. Ammonia is very corrosive, a property that causes most of the negative human health effects. Much like most toxic volatile liquids, ammonia vapor can cause chemical burns of the respiratory tract, skin, and eyes upon inhalation. Upon contact with the water present in skin, mucous membranes, and eyes, it forms ammonium hydroxide, which is a highly ionized weak base that causes tissue necrosis. Specifically, ammonium hydroxide causes saponification of cell membrane lipids resulting in cell disruption and death. Additionally, it dehydrates cells, which initiates an inflammatory response, and further damages the surrounding tissues. Direct contact with liquid ammonia results in cryogenic injury in addition to the alkali burns. Airway blockage and respiratory insufficiency may be lethal outcomes of exposure to anhydrous ammonia vapors or concentrated aerosols. Ingestion of concentrated ammonium solutions may produce severe burns and hemorrhage of the upper gastrointestinal (GI) tract. Hemorrhaging and open wounds of the GI tract can lead to infection and necrosis. The negative effects that have been observed in humans exposed to ammonia gas and ammonium salt aerosols have also been observed in animals. Hepatic and renal effects have been reported in animals and humans (US EPA, 1991c). The US EPA (1991c) has released the toxicological properties for ammonia given in Table 6.6.

Benzene Benzene is another hazardous air pollutant that can result from the papermaking process. Benzene (CASRN 71-43-2) is an organic chemical compound with chemical formula C6H6. It is a colorless and highly flammable liquid, with a sweet smell. It is an important industrial solvent and precursor in the production of drugs, plastics, synthetic rubber, and dyes. It is a gasoline additive, but due to its health effects it is now highly controlled. The EPA has classified benzene as a hazardous air pollutant. Regulations and laws have been put into place since the 1970s in order to control and limit the amount of benzene released into the environment. Benzene can be absorbed into the system through inhalation, oral ingestion, and skin contact. Dermal Table 6.6 Toxicological characterization data for ammonia RfC

LD50 (rats)

LC50 (rats)

LOAEL

NOAEL

PEL

0.1 mg/m3

350 mg/kg

5.4 g/m3 (1 h)

17.4 mg/m3

6.4 mg/m3

35.5 mg/m3

208

Handbook of Pollution Prevention and Cleaner Production

absorption is rare, however, due to benzene’s rapid evaporation from the skin. Distribution throughout the body occurs quickly after exposure by all routes, and accumulation in fatty tissues is also apparent. Individual case reports of death from acute oral exposure to benzene have appeared in the literature since the early 1900s. The benzene concentrations ingested by the victims often were not known. However, lethal oral doses for humans have been estimated at approximately 125 mg/kg (Thienes and Haley, 1972). Accidental ingestion and attempted suicide with lethal oral doses of benzene have produced the following signs and symptoms: staggering gait, vomiting, shallow and rapid pulse, somnolence, and loss of consciousness followed by delirium, pneumonitis, collapse, and then central nervous system depression, coma, and death (Thienes and Haley, 1972). Human exposure to benzene occurs primarily via inhalation in the workplace, from gasoline vapors, tobacco smoke, and automotive emissions. Individuals exposed to benzene exhibit bone marrow depression, as evidenced by anemia (decreased red blood cell (RBC) count), leukopenia (decreased white blood cell (WBC) count), and/or thrombocytopenia (decreased platelet count). A depression of all three elements is called pancytopenia, and the simultaneous depression of RBCs, WBCs, and platelets, accompanied by necrosis of the bone marrow, is diagnostic of aplastic anemia. Patients with aplastic anemia also have exhibited bilirubinemia, changes in osmotic fragility of erythrocytes, shortened erythrocyte survival time, increased fecal urobilinogen, and mild reticulocytosis (Aksoy, 1991). The human occupational inhalation study of Rothman et al. (1996) was selected by the EPA as the principal study for determining the RfC and RfD of benzene. Table 6.7 summarizes the study’s findings. Benzene is also classified as a known human carcinogen (category A) by the EPA and American Conference of Governmental Industrial Hygienists (ACGIH). Significantly increased risks of leukemia, chiefly acute myelogenous leukemia, have been reported in benzene-exposed workers in the chemical industry, shoemaking, and oil refineries. Aksoy et al. (1974) reported effects of benzene exposure among 28,500 Turkish workers employed in the shoe industry; 26 cases of leukemia and a total of 34 leukemias or preleukemias were observed, corresponding to an incidence of 13/100,000 (by comparison with 6/ 100,000 for the general population). Numerous additional studies continue to show that benzene is a dangerous human carcinogen. These studies show that

Table 6.7 Toxicological characterization data for benzene RfD

RfC

LD50 (rats)

LC50 (rats)

LOAEL

NOAEL

PEL

0.004 mg/ kg/day

0.03 mg/m3

930 mg/kg

32.4 g/m3 (7 h)

24.6 mg/m3

1.7 mg/m3

3.24 mg/m3

Source: Rothman et al. (1996).

Sources of air emissions from pulp and paper mills

209

the control of benzene emissions is a vital part of keeping the human population safe (US EPA, 2003a).

Chlorine dioxide Chlorine dioxide (CASRN 10049-04-4; ClO2) is a yellow to reddish-yellow gas at room temperature that is stable in the dark but unstable in the light. It is a strong oxidizing agent that under oxidant demand conditions is likely to reduce to chlorite (CASRN 7758-19-2; ClO 2 ), another strong oxidizing agent. This strong oxidizing ability makes it useful as a drinking water disinfectant. Other uses of chlorine dioxide include bleaching textiles and wood pulp. This bleaching process is what releases chlorine dioxide into the atmosphere and paper mill effluents. The EPA has classified chlorine dioxide as a regulated toxic substance. Exposure can occur via inhalation, ingestion, or skin contact. Since ClO2 is gaseous at room temperature, inhalation and dermal exposure are more common than ingestion, but there are reports of oral exposure. Two studies have been conducted to assess the short-term toxicity of chlorine dioxide. In the first study (Lubbers et al., 1981), a group of 10 healthy male adults drank 1000 ml (divided into two 500-ml portions, separated by 4 hours) of a 0 or 24 mg/l chlorine dioxide solution. In the second study (Lubbers et al., 1984), groups of 10 adult males were given 500 ml distilled water containing 0 or 5 mg/l chlorine dioxide for 12 weeks. Neither study found any physiologically relevant alterations in general health. Several case reports of accidental inhalation exposure to chlorine dioxide have been reported in the literature. Elkins (1959) described the case of a bleach tank worker who died after being exposed to 19 ppm chlorine dioxide (52 mg/m3) for an unspecified amount of time. A different worker exposed at the same time survived. Elkins also stated that 5 ppm was definitely irritating to humans. In a case reported by Exner-Freisfeld et al. (1986), a woman experienced coughing, pharyngeal irritation, and headache after inhaling an unknown amount of chlorine dioxide inadvertently generated while bleaching flowers. Seven hours after exposure, the woman was hospitalized with cough, dyspnea, tachypnea, tachycardia, rales on auscultation, marked leukocytosis and decreased lung function (US EPA, 2000). Using these and other studies, the EPA and Occupational Safety and Health Administration (OSHA) have obtained the toxicology data for chlorine dioxide given in Table 6.8. Table 6.8 Toxicological characterization data for chlorine dioxide RfD

RfC

LD50 (rats)

LC50 (rats)

LOAEL

NOAEL

PEL

0.03 mg/kg/day

0.0002 mg/m3

292 mg/kg

2.07 g/m3

193 mg/m3

386 mg/m3

0.3 mg/m3

Source: US EPA (2000).

210

Handbook of Pollution Prevention and Cleaner Production

Chlorine Chlorine (CASRN 7782-50-5; Cl2) is a highly toxic, greenish-yellow gas with the very pungent odor that gives swimming pools their smell. Chlorine gas is a powerful oxidant and is used in bleaching and disinfectants. Due to its behavior and adverse effects on human health, chlorine has been classified as a hazardous air pollutant and a regulated toxic substance by the US EPA. Humans are most likely to be exposed to chlorine through inhalation of the gas. Severe acute effects of chlorine exposure in humans have been well documented since World War I, when chlorine gas was used in chemical warfare. Other severe exposures have resulted from the accidental rupture of chlorine tanks. These exposures have caused death, lung congestion, pulmonary edema, pneumonia, pleurisy, and bronchitis (Hathaway et al., 1991). Even concentrations as low as 5 ppm caused respiratory complaints, corrosion of the teeth, inflammation of the mucous membranes of the nose, and susceptibility to tuberculosis among chronically exposed workers (ACGIH, 1991). Molecular chlorine is rarely found in its liquid phase unless low temperatures and high pressures are involved. If, somehow, a person comes into contact with this liquid, frostbite burns of the skin and eyes may occur (Genium, 1992). Table 6.9 shows the toxicology data for chlorine. Chlorine is very toxic and can be lethal in relatively low concentrations. Storage and transfer of chlorine for our many modern processes must be done carefully. Accidental leaks and releases cause serious human health problems and damage to the environment and ozone layer. Therefore, the release and emissions of chlorine gas must be kept to a minimum (US EPA, 1994b).

Chloroform Chloroform (CASRN 67-66-3), also called trichloromethane, is a colorless, volatile liquid with a distinct odor. It is a nonflammable substance with the chemical formula CHCl3. It is slightly soluble in water and is readily miscible with most organic solvents. Because of chloroform’s volatility, it tends to escape from contaminated environmental media (e.g. water or soil) into the air, and may also be released as vapor from some types of industrial or chemical operations, including the paper production process. Therefore, humans may be exposed to chloroform by ingestion of contaminated drinking water, food, or soil, by dermal contact with contaminated media (especially water), and by inhalation of vapor (especially in indoor air). Table 6.9 Toxicological characterization data for chlorine RfD

LD50 (rats)

LC50 (rats)

LOAEL

NOAEL

PEL

0.1 mg/kg/day

N/A

850 mg/m3 (1 h)

N/A

14.4 mg/kg/day

3 mg/m3

Source: US EPA (1994b).

Sources of air emissions from pulp and paper mills

211

The EPA has declared chloroform a hazardous air pollutant and a toxic substance due to its adverse effects on human health. The workplace, or other indoor facilities, are the most common sites of exposure by inhalation. A number of epidemiological studies have been performed to investigate the occurrence of adverse effects in populations of workers exposed to chloroform vapors in the workplace. These studies show that long-term exposure to concentrations of 20–200 ppm (100–1000 mg/m3) of chloroform produces mainly neurological effects. The symptoms observed are fatigue, nausea, vomiting, lassitude, dry mouth, and anorexia (Phoon et al., 1983). Some studies have also observed effects on the liver, including jaundice, increased serum enzyme levels, and increased liver size (Bomski et al., 1967; Phoon et al., 1983). Drinking water is often contaminated with chloroform, and this leads to human exposure by ingestion. There have been no studies of toxicity or cancer incidence in humans chronically exposed to chloroform alone, but there have been a number of studies on cancer risk in humans exposed to chlorinated drinking water. Chlorinated drinking water typically contains chloroform. It should also be noted that humans exposed to chloroform in drinking water are likely to be exposed both by direct ingestion and by inhalation of chloroform gas released from the water into indoor air. Some of the studies conducted detected association between exposure to chlorinated water and cancer (mainly bladder cancer). The EPA has not declared chloroform a human carcinogen, however, because of the uncertainty of exactly what impurity in the water was actually increasing cancer incidences (US EPA, 1994a, 1998a). Table 6.10 shows the toxicological data for chloroform. Although the EPA and other regulatory agencies have declared chloroform dangerous, there is not enough data and evidence to fully understand chloroform’s effect on human health. If cities and countries continue to use chlorination to purify drinking water, it is important that researchers continue to study chloroform. If studies are not conducted, the future could be filled with unforeseen problems caused by chlorinated drinking water (US EPA, 2001).

Chromium(VI) Hexavalent chromium (CASRN 18540-29-9) is, and can react to form, many different dangerous chemicals that are released by the paper industry. Chromium(VI) refers to chemical compounds that contain the element chromium in the þ6 oxidation state. Chromium can exist as oxo species such as CrO3 and Table 6.10 Toxicological characterization data for chloroform RfD

LD50 (rats)

LC50 (rats)

LOAEL

NOAEL

PEL

0.01 mg/kg/day

1194 mg/kg

47 g/m3 (4 h)

12.9 mg/kg/day

NA

240 mg/m3

Source: US EPA (2001).

212

Handbook of Pollution Prevention and Cleaner Production

CrO2 4 , which are strongly oxidizing. In solution, it exists as hydrochromate 2 2 (HCrO 4 ), chromate (CrO4 ), and dichromate (Cr2O7 ) ionic species (Cotton and Wilkinson, 1980). Hexavalent chromium may exist in aquatic media as water soluble complex anions and may persist in water (Callahan et al., 1979). Humans can be exposed to chromium via inhalation, ingestion or skin contact. Cr(VI) is considerably more toxic than Cr(III). A cross-sectional study of 155 villagers reported the effects of environmental contamination of well water adjacent to a chromium alloy plant. Cr(VI) concentrations were reported as 20 mg/l, with an estimated dose rate of 0.57 mg/kg/day (Zhang and Li, 1987). Reported effects at this dose included oral ulcers, diarrhea, abdominal pain, indigestion, vomiting, leukocytosis, and presence of immature neutrophils. Other reports of toxic effects in humans are limited to case reports from accidental poisonings. Some Cr(VI) compounds (such as potassium tetrachromate and chromic acid) are potent oxidizing agents, and are thus strong irritants of mucosal tissue. Effects included metabolic acidosis, acute tubular necrosis, kidney failure, and death (Saryan and Reedy, 1988). Occupational exposure to chromium compounds has been studied in the chromate production, chrome-plating, chrome pigment, ferrochromium production, gold mining, leather tanning, and chrome alloy production industries. Mancuso and Hueper (1951) conducted a proportional mortality study of a cohort of chromate workers (employed for longer than 1 year from 1931 to 1949 in a Painesville, OH, chromate plant) in order to investigate lung cancer associated with chromate production. Of the 2931 deaths of males in the county where the plant is located, 34 (1.2%) were due to respiratory cancer. Of the 33 deaths among the chromate workers, however, 6 (18.2%) were due to respiratory cancer. Within the limitations of the study design, this report strongly suggested an increased incidence in cancer in the chromate production plant. Chronic or acute inhalation can also lead to metal fume fever, which is characterized by flu-like symptoms with metallic taste, fever, chills, cough, weakness, chest pain, muscle pain, and increased WBC count. Coughing, fever, weight loss, and pneumoconiosis are also common. Table 6.11 shows the toxicology data for chromium(VI). Chromium(VI) and all the compounds it associates with are highly dangerous. Any employees or neighbors of a chromium plant should take notice and necessary precautions to reduce their risk of cancer or other health effects (US EPA, 1998b). Table 6.11 Toxicological characterization data for chromium(VI) RfD

RfC

LD50 (rats) LC50 (rats)

0.003 8  106 52 mg/kg/day mg/kg mg/m3 Source: US EPA (1998b).

LOAEL

NOAEL

PEL

217 2.5 1 0.002 mg/m3 (4 h) mg/kg/day mg/m3 mg/m3

Sources of air emissions from pulp and paper mills

213

Dioxins A dioxin is a heterocyclic, organic, anti-aromatic compound with the chemical formula C4H4O2. The term ‘‘dioxins’’, however, is commonly used to describe hazardous air pollutants known as polychlorinated dibenzodioxins (PCDDs). These PCDDs are created by the combination of chlorine and heat, along with a few other necessary components. The release of dioxins is very common in combustion, chlorine bleaching, and manufacturing processes. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is the best known and most toxic PCDD. TCDD is one of the most, if not the most, toxic and carcinogenic substances known to man. TCDD has been given a 1 on the toxic equivalency factor (TEF), which is based on a scale from 0 to 1, 1 being the highest. Although it has the highest TEF rating possible, TCDD’s toxicity varies greatly from species to species. For example, in guinea-pigs, an LD50 of 0.6 mg/kg was recorded, as compared with an LD50 of greater than 5000 mg/kg in Syrian hamsters. Explanations for this variation include differences in the Ah receptor, such as size, transformation, and binding to the dioxin response element, pharmacokinetics (metabolic capacity, tissue distribution), and body fat content (Geyer et al., 1990; Pohjanvirta et al., 1998; van den Berg et al., 2000). TCDD is very dangerous because it bioaccumulates in fatty tissues very well, and takes a very long time to metabolize and remove from the body. Exposure to small concentrations over time can lead to the buildup of dangerous levels. Humans are mostly exposed to TCDD through inhalation of polluted air or ingestion of contaminated foods. The International Agency for Research on Cancer (IARC) classified TCDD as a Group 1 carcinogen. High levels of exposure have been shown by epidemiological studies to lead to an increased risk of tumors at all sites (Zambon et al., 2007). Noncancer effects on human health include a severe form of persistent acne, called chloracne, developmental abnormalities in the enamel of children’s teeth, central nervous system pathology, thyroid disorders, damage to immune systems, endometriosis, and diabetes. Studies performed on animals have shown even more adverse effects of exposure to TCDD. One study performed by Kociba et al. (1976) exposed rats to TCDD concentrations of 0.001–1 mg/kg/day. More than half of the rats that were exposed to 1 mg died within the trial period of 13 weeks plus 49 days of post-trial observation. The rats exposed to the lesser doses showed signs of increased liver weight. Smits-van Prooije et al. (1993) conducted a study on 30 pregnant rats. The rats were given a single dose of 0, 0.2, 0.6 or 1.8 mg/kg. Their pups were followed through to breeding about 1 year later. The high-dose pups had 2/16 successful pregnancies, compared to 15/17 and 11/17 at the 0.2 and 0.6 mg/kg doses. This study provides strong evidence for the fact that TCDD has adverse effects on mating behavior and fertility. There is not much toxicological data, such as LOAEL, NOAEL, RfC, and RfD for TCDD, but the known LD50 for rats is 0.043 mg/kg (Stahl et al., 1992). This is lower than the value for the previously discussed chemicals.

214

Handbook of Pollution Prevention and Cleaner Production

Dioxins are among the worst pollutants in the atmosphere today. They are very toxic and carcinogenic, and it is very hard to rid them from the human body. Present and future emission standards need to pay close attention to them in order to keep the public safe (Canady et al., 2001).

Ethylene glycol Another pollutant involved in the paper industry is ethylene glycol (CASRN 107-21-1). Ethylene glycol is an alcohol with two –OH groups (a diol), chemical formula C2H4(OH)2. In its pure form, it’s an odorless, colorless, syrupy, sweet tasting, toxic liquid with a melting point of 13 C. The major use of ethylene glycol is as a medium for convective heat transfer. It can be used as a deicing agent for aircraft and windshields or in chilled water air-conditioning systems. Exposure to ethylene glycol is usually through ingestion. Inhalation and skin contact can also occur, but since ethylene glycol’s boiling point is so high (197 C), it is rarely in gaseous form. Inhalation and skin contact may cause irritation, but there is low hazard for these types of exposure. Chronic exposure can cause kidney problems. Unlike the minor irritations experienced from inhalation and skin contact, the adverse effects of the ingestion of ethylene glycol are very harmful and can result in death. Due to its sweet taste, children and animals will occasionally consume large quantities of ethylene glycol if given access to antifreeze. Upon ingestion, ethylene glycol is oxidized to glycolic acid, which is then oxidized to oxalic acid, which is highly toxic. These chemicals lead to ethylene glycol poisoning, which is characterized by three stages. Stage 1 (0.5–12 hours) consists of neurological and GI symptoms. People may appear to be intoxicated, exhibiting symptoms such as dizziness, incoordination, nystagmus, headaches, slurred speech, and confusion. Irritation to the stomach may cause nausea and vomiting. Stage 2 (12–36 hours) is a result of accumulation of the organic acids formed by the metabolism of ethylene glycol. Symptoms consist of increased heart rate, high blood pressure, hyperventilation, and metabolic acidosis. Additionally, low calcium levels in the blood, overactive muscle reflexes, muscle spasms, and congestive heart failure may occur. If untreated, death most commonly occurs during this stage. Stage 3 (24–72 hours) is the result of kidney injury. Symptoms consist of acute tubular necrosis, red blood and excess proteins in the urine, lower back pain, decreased production of urine, and acute kidney failure. Kidney failure can be reversed, but can take months of supportive care. Table 6.12 shows the toxicological data for ethylene glycol. Table 6.12 Toxicological characterization data for ethylene glycol RfD

LD50 (rats)

2 mg/kg/day 4700 mg/kg Source: US EPA (1987).

LC50 (rats) LOAEL –

NOAEL

PEL

1000 mg/kg/day 200 mg/kg/day 125 mg/m3

Sources of air emissions from pulp and paper mills

215

Ethylene glycol poisoning can also occur in aquatic life forms, but high concentrations are needed for the effects to be fatal. Long-term effects on marine life are not substantial due to ethylene glycol’s readiness to biodegrade in water or on soil (US EPA, 1987).

Formaldehyde Formaldehyde (CASRN 50-00-0) is another chemical that is emitted by pulp and paper mills. It is the simplest aldehyde and has the formula CH2O. Formaldehyde is an intermediate in the combustion of methane as well as other carbon compounds. In addition to paper mills, forest fires, car exhausts, and cigarette smoke are all important sources of formaldehyde. Its boiling point is 19 C, so it is usually found in gaseous form, but both its liquid and vapor states are very flammable. Due to its low boiling point, it is usually found in aqueous solutions, called formalin. Oral exposure is usually to formalin and not formaldehyde itself. A saturated formalin solution is 37% formaldehyde by weight. The EPA has classified formaldehyde as a hazardous air pollutant and a controlled toxic substance due to its variety of adverse health effects. Exposure can occur through inhalation, ingestion, and contact with the skin and eyes. Exposure to human eyes can lead to irritation, chemical conjunctivitis, and corneal damage. Contact with the skin can cause irritation, skin sensitization, allergic reactions, and cyanosis of the extremities. Formaldehyde is toxic to both terrestrial and aquatic animals. Animals tested showed symptoms similar to those of humans. Exposure by inhalation is also hazardous to human health. Adverse effects of inhalation include nervous system effects, such as nausea, headache, dizziness, unconsciousness, and coma. Inhalation also leads to respiratory tract irritation. Severe asthma attacks can occur due to allergic sensitization of the respiratory tract. These attacks can lead to pulmonary edema. After inhalation occurs the exposed person or animal must be moved to fresh air to relieve the symptoms. Failure to do so can cause permanent damage or suffocation. Ingestion of pure formaldehyde is rare due to the scarcity of its liquid phase. Ingestion of formalin is much more common. Even though formalin is an aqueous solution, it is very harmful to humans and animals. Ingestion of formaldehyde may cause GI irritation with nausea, vomiting, and diarrhea. Large doses can cause nervous system depression, characterized by excitement, followed by headache, dizziness, drowsiness, and nausea. Advanced stages may cause collapse, unconsciousness, and coma. Ingestion can also be fatal or cause permanent blindness. Animals are also affected by the ingestion of formaldehyde. A study was conducted where formaldehyde was administered daily in test rats’ drinking water. Chronic ingestion led to many adverse effects, including decreased body weight, decreased water intake, decreased organ weight, increased brain weight, and digestive system damage (Til et al., 1989). Exposure to pregnant rats lead to increased numbers of resorption sites and decreased litter size. No effects on fetus size were reported (Marks et al., 1980).

216

Handbook of Pollution Prevention and Cleaner Production

Table 6.13 Toxicological characterization data for formaldehyde RfD

LD50 (rats)

LC50 (rats)

LOAEL

NOAEL

PEL

0.2 mg/kg/day

100 mg/kg

203 mg/m3

83 mg/kg/day

15 mg/kg/day

0.92 mg/m3

Source: US EPA (1991d).

Chronic exposure to formaldehyde is also dangerous. Repeated exposure may cause skin discoloration and thickening as well as nail decay. In addition, the OSHA and the ACGIH have labeled formaldehyde as a class A2 suspected human carcinogen. Chronic inhalation of formaldehyde has been associated with nasal and nasopharyngeal cancer in humans. Consequences of inhalation exposure have also been studied in rats, mice, hamsters, and monkeys. Evidence supporting formaldehyde as a carcinogen comes from positive studies in both sexes of two strains of rats and males of one strain of mice, all of which showed squamous cell carcinomas (Albert et al., 1982; Kerns et al., 1983; Tobe et al., 1985). These studies, as well as others, led to the toxicological data for formaldehyde given in Table 6.13.

Formic acid Formic acid (CASRN 64-18-6) is another pollutant released by the paper industry. It is the simplest carboxylic acid and has the chemical formula HCOOH. For humans, it functions as an important intermediate in chemical synthesis and a preservative and antibacterial agent in livestock feed. In nature it is used as venom by ants and bees. It is generally found in aqueous solution, but the pure liquid and vapor are combustible and highly corrosive. Exposure can occur through inhalation, ingestion, or skin contact. The adverse effects of exposure are similar to those of acids such as HCl. Contact with liquid is corrosive to the eyes and causes severe burns, an increase in tears, corneal edema, ulceration, and scarring. Skin contact may cause skin sensitization, an allergic reaction, corrosive burns, and ulceration. Inhalation may cause asthmatic attacks due to allergic sensitization of the respiratory tract, chemical burns to the respiratory tract, dizziness, nausea, itching, burning, and swelling of the eyes. Ingestion may cause severe digestive tract burns with abdominal pain, vomiting, and possible death. Central nervous system depression is also a common consequence. Ingestion may produce corrosive ulceration and bleeding and necrosis of the GI tract accompanied by shock and circulatory collapse. The EPA has not labeled formic acid as a hazardous air pollutant or a toxic substance, but that does not mean formic acid is not harmful. The EPA has also recently withdrawn its assessment of the oral RfD value. Table 6.14 shows the toxicological data for formic acid (US EPA, 1996).

Sources of air emissions from pulp and paper mills

217

Table 6.14 Toxicological characterization data for formic acid LD50 (rats)

LC50 (rats)

LOAEL

NOAEL

PEL

1100 mg/kg

15 g/m3 (15 min)

N/A

42 mg/m3

9 mg/m3

Source: EPA (1996).

Hydrochloric acid Hydrochloric acid (CASRN 7647-01-0) is used then released via effluent flows by the paper industry. It is a solution of hydrogen chloride (HCl) dissolved in water. HCl is a highly corrosive, strong acid, and can be a clear/ colorless or light yellow liquid. It is used in the chemical industry mainly as a chemical reagent in the large-scale production of vinyl chloride for polyvinyl chloride plastic and methylene diphenyl diisocyanate/TDI for polyurethane. Also, since HCl ionizes completely into H3Oþ and Cl, it can easily be used to produce salts like sodium chloride (NaCl). HCl is usually produced with a concentration between 0% and 38% kg HCl/kg. If the concentration of HCl is very low, approaching 0% HCl, the solution behaves similarly to liquid water. If the concentration is high, above 30%, the boiling point decreases rapidly and evaporation rate increases. Forty percent HCl is known as ‘‘fuming’’ hydrochloric acid because of its extremely high evaporation rate. Due to its corrosive behavior, the EPA has classified HCl at concentrations of 37% and higher as a toxic substance. Mucous membranes, skin, and eyes are all susceptible to this corrosion. Acute inhalation may cause coughing, hoarseness, inflammation, and ulceration of the respiratory tract, chest pain, and pulmonary edema in humans. Additionally, these symptoms are increased for humans who suffer from asthma. Animals subjected to inhalation exposure suffered from irritation and lesions of the upper respiratory tract and laryngeal and pulmonary edema. Acute oral exposure may cause corrosion of the mucous membranes, esophagus, and stomach, with nausea, vomiting, and diarrhea reported in humans. Dermal contact may produce severe burns, ulceration, and scarring. Animals also show signs of moderate to high toxicity from acute oral ingestion. Aquatic animals are affected heavily by HCl due to the pH shift that occurs when HCl is added to the water. Chronic exposure to hydrochloric acid is also dangerous for humans and animals. In humans, long-term exposure has been reported to cause gastritis, chronic bronchitis, dermatitis, and photosensitization. Prolonged exposure to low concentrations may also cause dental discoloration and erosion. Rats subjected to chronic inhalation tests experienced hyperplasia of the nasal mucosa, larynx and trachea, and lesions in the nasal cavity (US EPA, 1995a). Table 6.15 shows toxicity data for HCl obtained by the EPA.

218

Handbook of Pollution Prevention and Cleaner Production

Table 6.15 Toxicological characterization data for hydrochloric acid RfC

LD50 (rats)

LC50 (rats)

LOAEL

NOAEL

PEL

0.02 mg/m3

N/A

4.7 g/m3 (30 min)

15 mg/m3

N/A

7 mg/m3

Source: US EPA (1995a).

Hydrogen fluoride Hydrogen fluoride (CASRN 7664-39-3; HF) is a nonflammable, colorless gas that is often expelled from the paper-making process. A solution of HF in water is known as hydrofluoric acid. This acid is highly corrosive. HF is the principal industrial source of fluorine and a precursor to many important compounds, including pharmaceuticals and polymers such as Teflon. Hydrogen fluoride is on both the hazardous air pollutant and toxic substance lists released by the EPA. This is due to its highly corrosive behavior, which has numerous adverse effects on human health when ingested, inhaled, or contacted with the skin or eyes. In humans, inhalation can cause immediate or delayedonset pulmonary edema. Significant exposures via the dermal or inhalation routes may cause hypocalcemia and hypomagnesemia, and cardiac arrhythmias may follow. Acute renal failure has also been documented after an ultimately fatal inhalation exposure. Repeated exposure to excessive concentrations of HF over a period of years results in increased bone density and eventually may cause crippling fluorosis, which is a form of osteosclerosis (Hathaway et al., 1991). Ingestion of HF is also extremely dangerous. Consequences are similar to those for other acids. Ingestion may cause burns and ulceration of the respiratory tract, damage to the GI tract, and permanent damage to any tissue that comes in contact with the solution. Ingestion of an estimated 1.5 g of hydrofluoric acid produces sudden death. If the exposed person is lucky enough to survive the first ingestion, repeated ingestion of small amounts of HF may cause fluoride osteosclerosis (Gosselin et al., 1984). The EPA does not have a reference dose or a reference concentration established. The only two pieces of toxicology data on HF are its 1-hour LC50 in rats of 1.56 g/m3, and its OSHA permissible exposure limit (PEL) of 3.7 mg/m3 (OSHA, 2009).

Hydrogen sulfide Hydrogen sulfide (CASRN 7783-06-4; H2S) is a major emission and the primary source of odor of most paper mills. Most pulping processes use sulfur solutions and compounds to break down the lignin that binds the cellulose fibers together. Many of these sulfuric compounds escape as emissions and cause the smell characteristic of rotten eggs or flatulence. Synonyms of H2S, such as sewer gas and stink damp, give even more detail to its pungent odor. In addition to its smell, H2S is colorless, toxic, and flammable.

Sources of air emissions from pulp and paper mills

219

Exposure to humans mainly occurs due to inhalation and skin contact. Ingestion is highly unlikely because of its extremely low boiling point (60 C). Eye and skin contact may cause inflammation, irritation, and ‘‘gas eyes’’, symptoms of which include soreness, scratchiness, irritation, tearing, and burning. Above 50 ppm, there is an intense tearing, blurring of vision, and pain when looking at light. Exposed individuals may see rings around bright lights. Most symptoms disappear when exposure ceases; however, in serious cases, the eye can be permanently damaged. Inhalation of high concentrations of H2S can cause dizziness, headache, and nausea. Exposure to even higher concentrations can result in respiratory arrest, coma, or unconsciousness. Exposures to 30 minutes at concentrations of greater than 600 ppm have been fatal. Severe exposures that do not result in death may cause long-term symptoms such as memory loss, paralysis of facial muscles, or nerve tissue damage. A study by Burnett et al. (1977) showed hard evidence of these symptoms. A 19-year-old oil-rig worker had been exposed to unspecified concentrations of H2S, rendering him unconscious for an indeterminate amount of time. Upon resuscitation, he exhibited malaise, anterior chest pain, dyspnea, headache, nausea and vomiting, tearing of the eyes and photophobia, and coughed up blood. Upon arrival at the hospital for further treatment, his vital signs were normal and he was no longer in respiratory distress. He had severe photophobia and blepharospasms, but no signs of conjunctivitis. He also possessed a cough and some motor weakness of his right arm and leg. A neurologic examination and chest X-ray revealed no abnormalities. He was released from the hospital after a 3-day stay. Hydrogen sulfide has never been associated with an increased risk of cancer, so the EPA and similar agencies have declared it noncarcinogenic to humans. Additional toxicological data for H2S are shown in Table 6.16. Due to its odor, H2S is very easy to detect and distinguish. Since paper mills emit a relatively large amount of H2S, they are very unpleasant to work in or live by. There are sulfur control apparatuses in use today, but they can never keep the smell contained completely. Odor has been linked to health issues such as olfactory fatigue and recurring nausea. The paper industry needs to realize the problems that H2S causes, and hopefully they can invent a new process that does not require such ghastly chemicals (US EPA, 2003b).

Table 6.16 Toxicological characterization data for hydrogen sulfide RfD

RfC

LD50 (rats) LC50 (rats) LOAEL

0.003 mg/ kg/day

0.002 mg/ m3

N/A

Source: US EPA (2003b).

617 mg/m3 41.7 mg/ (5 min) m3

NOAEL

PEL

13.9 mg/ m3

27.8 mg/ m3

220

Handbook of Pollution Prevention and Cleaner Production

Methanol Methanol (CASRN 67-56-1) is the primary chemical emitted by the paper industry, and is ranked third among all chemicals for total releases into the environment (1992). Methanol, also known as methyl alcohol and wood alcohol, is a toxic chemical with the formula CH3OH. It is the simplest alcohol and is a light, colorless, volatile, flammable liquid with an odor similar to ethanol. It occurs naturally in wood and volcanic gases, and it can also be produced naturally by decaying organic material. Man-made production of methanol totalled 1.3 billion gallons a year (1992) in the USA alone. Its main industrial use is the production of methyl t-butyl ether, a gasoline additive, but it can also be used to produce other chemicals and commercial products. Humans can be exposed to methanol through air, water, soil, or groundwater. Methanol can enter the body by inhalation or consumption of contaminated food or water. It can also be absorbed through skin contact. Exposure can occur when using certain paint thinners, aerosol sprays, paints, windshield wiper fluid, or small engine fuel. The EPA has declared methanol an HAP due to its adverse health effects on humans. The nature and intensity of these effects depend on the concentration and time of exposure. The health of the person or animal exposed as well as the conditions of the environment can also influence the effects of exposure. Acute exposure to methanol is very dangerous and can be fatal. The ingestion of 80 ml is usually fatal for humans. Poisoning by nonlethal doses is common and involves three stages: (1) narcotic stage similar to ethanol; (2) latent period of 10–15 hours; (3) visual disturbances and central nervous system lesions, including headache, dizziness, nausea, and delirium that can lead to coma. In fact, blindness has been caused by the ingestion of as little as 20 ml. Once methanol is consumed, it is oxidized by the human liver to form formaldehyde and formic acid. This formic acid is responsible for the toxic effects of methanol. Table 6.17 describes important toxicity properties of methanol. Human health effects associated with chronic exposure to methanol are not completely known. Workers exposed repeatedly over long periods of time experienced adverse effects, including headaches, sleep disorders, and GI problems. In many cases, optic nerve damage was also apparent. Lab studies show that repeated exposure to large amounts of methanol in air or in drinking water cause similar adverse effects in animals (US EPA, 1988).

Table 6.17 Toxicological characterization data for methanol RfD

LD50 (rats)

LC50 (rats)

LOAEL

NOAEL

PEL

0.5 mg/kg/day 6.2–13 g/kg 85.1 g/m3 (1 h) 2.5 g/kg/day 10 mg/kg/day 4.3 mg/m3 Source: US EPA (1988).

Sources of air emissions from pulp and paper mills

221

Methyl mercaptan Methyl mercaptan (CASRN 74-93-1; CH4S), also known as methanethiol, is a toxic, extremely flammable, colorless gas with a smell similar to rotten cabbage. It occurs naturally in the blood and brain, and in other animals and plant tissues. It is one of the main chemicals that cause bad breath and the odor of flatulence. Kraft pulp mills emit methyl mercaptan during the pulping process. An odorous plume that contains methyl mercaptan can be detected thousands of feet away from a kraft mill. The odor is so easily detected that methyl mercaptan, and other thiols, are added to otherwise odorless natural gas to aid in leak detection. In addition, methyl mercaptan is a by-product of asparagus in roughly 50% of humans, and it is responsible for the distinct change in odor of the urine (Richer et al., 1989). The EPA has declared methyl mercaptan a regulated toxic substance due to its adverse effects on human health. Exposure to humans can occur by eye/skin contact, inhalation, or ingestion, but ingestion is very unlikely due to methyl mercaptan’s volatility. Ingestion can cause irritation of the mucous membranes, causing a burning feeling with excess salivation. Eye exposure to low concentrations will generally cause irritation to the conjunctiva. Repeated exposure to low concentrations is reported to cause conjunctivitis, photophobia, corneal bullae, tearing, pain, and blurred vision. Irritation can be caused by skin contact as well. The most common form of human exposure to methanethiol is through inhalation. Exposure may cause fever, cough, shortness of breath, a feeling of tightness and burning in the chest, pulmonary edema, respiratory failure and collapse. Headache, loss of smell, dizziness, staggering gait, and heightened emotions may occur. Memory loss, damage to the central and peripheral nervous system, tremor, convulsions, and coma may also result. Individuals exposed to high concentrations may develop acute hemolytic anemia and methemoglobinemia. Individuals with pre-existing conditions of the heart, lungs, blood, and nervous system may have increased susceptibility to the toxic effects of methyl mercaptan. Methyl mercaptan is on the EPA’s list of regulated toxic substances, but there is a limited amount of toxicological data on methyl mercaptan; the LC50 for rats by inhalation for 1 hour is 1.3 g/m3, and the OSHA PEL is 19.7 mg/m3 (BOC, 1996).

Pentachlorophenol Pentachlorophenol (CASRN 87-86-5; C6HCl5O; PCP) is a synthetic substance that is often emitted by wood treatment industries. The main use for PCP is wood preservation, not the production of pulp and/or paper. PCP has been detected in surface waters and sediments, rainwater, drinking water, aquatic organisms, soil, and food, as well as in human milk, adipose tissue, and urine.

222

Handbook of Pollution Prevention and Cleaner Production

As PCP is generally used for its properties as a biocidal agent, there is considerable concern about adverse ecosystem and health effects in areas of PCP contamination. The EPA has placed PCP on the Clean Air Act of 1990 list of hazardous air pollutants due to these adverse effects. Humans can be exposed to PCP by inhalation and skin contact, usually at the workplace, or by ingestion of contaminated drinking water and food. Short-term exposure by ingestion, to large amounts of PCP, can cause harmful effects on the liver, kidneys, blood, lungs, nervous system, immune system, and GI tract. Other consequences include elevated temperature, profuse sweating, uncoordinated movement, muscle twitching, and possible coma. Inhalation of PCP vapor can produce similar symptoms plus irritation of the skin and eyes. Chronic exposure to low levels of PCP, such that can occur at the workplace, can cause damage to the liver, kidneys, blood, and nervous system. Also, PCP has been classified as a B2, probable human carcinogen. There is inadequate data to fully declare PCP a human carcinogen, but there were a couple of studies to examine its cancer-causing potential. Gilbert et al. (1990) attempted to study the effects of exposure to PCP among a cohort of 182 men employed by the wood-treating industry in Hawaii. The workers had experienced a minimum of 3 months’ continuous employment treating wood between 1960 and 1981. The study showed elevated levels of urinary PCP among the wood treaters, but no morbidity or mortality endpoint was achieved. Studies in animals have provided the solid evidence on the cancerous effects of exposure to PCP. In one of these studies, conducted by NTP (1989), two different 90% pure preparations of PCP were tested in 2-year bioassays in mice. The incidences of hepatocellular adenomas and/or carcinomas were significantly increased in exposed test subjects compared to controls. Also, the incidences of benign and malignant pheochromocytomas of the adrenal medulla were also significantly greater in dosed mice than in controls. The EPA continues to study PCP and has released the toxicological data shown in Table 6.18. The full effects of exposure to PCP are not known. Continued studies concerning the carcinogenic and noncancerous health effects on humans are needed. Even though there is limited information and data concerning PCP, it is safe to say that it is harmful and needs strict regulation (US EPA, 1991e).

Table 6.18 Toxicological data for pentachlorophenol RfD

LD50 (rats) LC50 (rats)

0.03 mg/kg/day 27 mg/kg Source: US EPA (1991e).

LOAEL

NOAEL

PEL

5.5 g/mg3 (4 h) 10 mg/kg/day 3 mg/kg/day 0.5 mg/m3

Sources of air emissions from pulp and paper mills

223

Phenol Another chemical commonly emitted by the paper industry is phenol. Phenol (CASRN 108-95-2), also known as carbolic acid, has the chemical formula C6H5OH. It is a combustible, corrosive, toxic, white crystalline solid with a sweet tarry odor, commonly referred to as a ‘‘hospital smell’’. Phenol is moderately soluble in water and commonly seen in aqueous solutions. Since it is toxic to bacteria and fungi, phenol used to be used as an antiseptic, but now it is mainly used as an intermediate in the production of phenolic resins, which are used in the plywood, adhesive, construction, automotive, and appliance industries. Phenol is readily absorbed by inhalation, oral, and dermal routes. Once absorbed, phenol is widely distributed throughout the body, but the levels in the lung, liver, and kidney are often reported as higher than average. Elimination from the body is rapid, and phenol does not appear to accumulate significantly in the body. The EPA has established that phenol is a hazardous air pollutant due to its adverse effects on human and animal health. Exposure can occur through skin and/or eye contact, inhalation, and ingestion. Adverse effects caused by eye contact include severe burns, chemical conjunctivitis, corneal damage, and possible irreversible eye damage. Skin contact may lead to wrinkled discoloration followed by severe burns. If not properly taken care of, phenol solutions may be rapidly absorbed through the skin, causing systematic poisoning and possible death. Ingestion of phenol is harmful and can be fatal. Its nonfatal effects include depression of the central nervous system, characterized by excitement, followed by headache, dizziness, drowsiness, and nausea. Advanced stages may cause collapse, unconsciousness, and coma. Perforation and burning of the digestive tract are common consequences, as well as immediate pain and swelling in the throat, convulsion, and possible coma. Studies of animals exposed to phenol have shown further negative effects. Argus Research Laboratories (1997) held a large-scale oral toxicity study on rats. This study showed adverse effects similar to those in humans. Pregnant rats were also exposed to phenol, and the consequences of that included an increase in abortions and still births, decreased fetal weight, and an increase in litters with alterations. Exposure to phenol through inhalation also leads to adverse health effects and possibly death. Inhalation causes severe irritation of the respiratory tract with coughing, burns, and breathing difficulty. Other nonfatal problems include pallor, loss of appetite, nausea, vomiting, diarrhea, weakness, darkened urine, headache, sweating, convulsions, cyanosis, unconsciousness, fatigue, pulmonary edema, and coma. Inhalation of high concentrations may cause central nervous system depression, asphyxiation, and death. Phenol is toxic to aquatic animals, but it biodegrades rapidly, so contamination in water is usually short term. A common way phenol contaminates water is rain absorbing it from the atmosphere (US EPA, 2002). Table 6.19 shows the toxicological values for phenol.

224

Handbook of Pollution Prevention and Cleaner Production

Table 6.19 Toxicological characterization data for phenol RfD

LD50 (rats)

LC50 (rats)

LOAEL

NOAEL

PEL

0.3 mg/kg/day

317 mg/kg

316 mg/kg

120 mg/kg/day

60 mg/kg/day

19 mg/m3

Source: US EPA (2002).

Sulfuric acid Sulfuric acid (CASRN 7664-93-9), also known as hydrogen sulfate, is a highly corrosive, clear, colorless, odorless, strong mineral acid with the formula H2SO4. It is also one of the top 10 chemicals released (by weight) by the paper industry (US EPA, 2009). In modern industry, sulfuric acid is an important commodity chemical, and is used primarily for the production of phosphoric acid. It is also good for removing oxidation from iron and steel, so it is used in large quantities by metal manufacturers. Sulfuric acid is a very dangerous chemical. It is extremely corrosive and toxic. Exposure can occur from inhalation, ingestion, and through skin contact. Inhalation of H2SO4 may cause irritation and/or chemical burns to the respiratory tract, nose, and throat. Inhalation can also be fatal as a result of spasm, inflammation, edema of the larynx and bronchi, chemical pneumonitis, and pulmonary edema. Chronic inhalation is known to have caused kidney and lung damage in addition to nosebleeds, erosion of the teeth, chest pain, and bronchitis. The effects of ingesting sulfuric acid orally are just as bad as inhalation. Ingestion may cause systematic toxicity with acidosis, which can be fatal. It can also cause severe permanent damage to the digestive and GI tracts. Prolonged or repeated ingestion is not common because the first ingestion is usually the last. Skin or eye contact with sulfuric acid can be devastating. The burns induced are similar, and often worse, than those caused by hydrochloric acid. What makes sulfuric acid so dangerous is its exothermic reaction with water. When introduced to water or moisture, the solution reacts with the water to create hydronium ions. This reaction releases large amounts of heat to the environment. This reaction is so strong that concentrated sulfuric acid can char paper by itself (see Figure 6.10). Recurring contact with the skin is known to cause dermatitis, and repeated contact with the eyes can cause permanent visual problems. Another deadly property of sulfuric acid is its carcinogenicity. The International Agency for Research on Cancer (IARC) has classified ‘‘strong inorganic acid mists containing sulfuric acid’’ as a group 1 known human carcinogen. The ACGIH also classified sulfuric acid mists as a category A1 carcinogen. This only applies to mists, and not to liquid sulfuric acid and its solutions (ISU, 2000). Table 6.20 shows toxicology values for sulfuric acid.

Sulfur dioxide Sulfur dioxide (CASRN 7446-09-5; SO2) is another odorous pollutant released by the paper industry. Sulfur dioxide is a nonflammable, colorless, irritating gas.

Sources of air emissions from pulp and paper mills

225

Figure 6.10 Sulfuric acid (98%) on tissue paper. Source: Wikipedia; http://en.wikipedia.org/wiki/Sulfuric_acid

It has a suffocating odor, detectable at 3–5 ppm, and leaves an acidic taste in the mouth. It is toxic and corrosive, and highly soluble in water. Most man-made/ released SO2 is associated with the burning of fossil fuels. In nature, SO2 can be produced by volcanic eruptions. Much like hydrogen sulfide, SO2 is a primary reason paper mills smell the way they do. This odor is not only unpleasant, but can be harmful as well. The EPA lists SO2 as a regulated toxic chemical due to its adverse effects on human health. Inhalation of SO2 can cause corrosive irritation to the respiratory tract and mucous membranes. Excess exposure to concentrations above exposure limits may result in chemical pneumonitis (inflammation), pulmonary hemorrhage, and edema fluid buildup. Inhalation exposure has also resulted in death. In one study, an SO2 level of 150 ppm was measured during the re-enactment of an incident in which a 76-year-old asthmatic woman died of an asthma attack after inhaling vapors from a sulfite-based derusting agent used in her dishwasher (Huber and Loving, 1991). Actual SO2 levels were probably higher since the quantity of derusting agent used in the investigation was about 10% of the amount originally used by the woman. A concentration of 100 ppm is considered immediately dangerous to human life and health (HSDB, 1998). Table 6.20 Toxicological characterization data for sulfuric acid RfC

LD50 (rats)

LC50 (rats)

LOAEL

NOAEL

PEL

0.001 mg/m3

2.14 g/kg

510 mg/m3 (2 h)

380 mg/m3

N/A

1 mg/m3

Source: ISU (2000).

226

Handbook of Pollution Prevention and Cleaner Production

Exposure by oral ingestion is nearly impossible due to sulfur dioxide’s low boiling point (10 C). Exposure to skin and eyes can cause irritation and burning. High concentrations or long-term exposure can lead to impaired vision or vision loss. Since ingestion is not plausible there are no data regarding the RfD, NOAEL, or LOAEL. The two pieces of available toxicological data are the LC50 for rats of 6.6 g/m3 for 1 hour, and the OSHA PEL of 13 mg/m3. There is no definitive evidence for an increased cancer potential from SO2 in humans, but some studies have shown increased cancer risk. Several epidemiological studies have been conducted on copper smelter workers and pulp and paper workers who can be exposed to SO2 (IARC, 1992). A nested case–control study of lung cancer among 308 workers in a large chemical facility revealed significantly elevated risks for workers with moderate and high potential exposure (longer than 1 year) to SO2 (Bond et al., 1986). For workers who had been exposed, the odds ratio for lung cancer was 1.40. Although SO2 is not on the EPA’s hazardous air pollutants list, it is still a dangerous chemical. The odor is painful and irritating, and inhaling the chemical can lead to serious adverse health effects. Perhaps it’s time SO2 made the hazardous air pollutants list (US DHHS, 1998).

Toluene Toluene (CASRN 108-88-3) is another major chemical released by the paper industry. Toluene, a.k.a. methyl benzene, is a clear, flammable, water-insoluble liquid with the odor of paint thinner. It can be found naturally in petroleum crude oil. Exposure to toluene can occur through air, water, soil, and groundwater, but almost all of the toluene released as emissions is dispersed into the air. Industrial emissions, car exhausts, and cigarette smoke (cigarettes contain about 80 mg/cigarette) are three large sources of atmospheric toluene. The EPA has labeled toluene as an HAP and a toxic substance. Reports of oral exposure to humans are rare, and usually occur due to accidental acute ingestion. Ameno et al. (1989) reported 15 deaths by oral ingestion between 1977 and 1986. The cause of death was believed to be severe central nervous system depression. Caravati and Bjerk (1997) discussed a case where a 46-year-old man ingested nearly 1 quart of paint thinner containing toluene. The man experienced severe central nervous system depression, severe abdominal pain, diarrhea, and hemorrhagic gastritis. He recovered after 36 hours of supportive care. Repeated exposure to toluene can cause permanent central nervous system effects, and can damage the liver, kidney, and upper respiratory system. Exposure through inhalation is much more common. People ‘‘huff’’ or ‘‘sniff’’ paint, paint thinner, or glue in order to feel the euphoric effects of a large dose of toluene. Inhalation of toluene can lead to a variety of neurologic manifestations, including ataxia, tremor, anosmia, sensorineural hearing loss, dementia, corticospinal tract dysfunction, and epileptic seizures (Hormes et al., 1986). Hunnewell and Miller (1998) reported a case study where a 36-year-old chronic toluene abuser exhibited slurred speech, progressive ataxia, blurred vision, and

Sources of air emissions from pulp and paper mills

227

oscillopsia (jerky eye movement). High concentrations (10,000–30,000 ppm) can cause narcosis and death. A study in France on workers chronically exposed to toluene fumes reported leukopenia and neutropenia. Exposure levels were not given, but the average urinary excretion of hippuric acid, a metabolite of toluene, was given at 4 g/l compared to the normal level of 0.6 g/l (Sandmeyer, 1989). Table 6.21 shows toxicological data for toluene obtained by the EPA and OSHA. Reports and studies have shown that toluene does not contribute to the formation of cancer in humans. Both the OSHA and ACGIH had labeled it as a noncarcinogen. Even though this is true, toluene should not be used recreationally or emitted irresponsibly due to the damage it causes to the nervous system (US EPA, 2005).

6.4 Regulations The sector is subject to the same environmental regulations as other industry sectors, but the most significant recent rulemaking activities affecting the pulp and paper sector are referred to collectively as the Cluster Rules (1998). This refers to a set of air and water rules that were issued simultaneously. The rules include: the Pulp and Paper NESHAP, specifying air emission standards for pulping and bleaching operations; the Effluent Limitations Guidelines and related water-quality standards for the pulp, paper, and paperboard category.

 

Estimates of the emissions reductions expected include:   

a 64% reduction in HAPs (by 153,000 tons per year, down from 240,000 tons emitted during 1996); a 450,000 ton per year reduction in overall VOC emissions (as a consequence of implementing the technology needed to meet the HAP rules); an 87,000 ton per year reduction in emissions of odor-causing reduced sulfur compounds (as a consequence of new source performance standards).

The water-quality standards specified under the Cluster Rules regulate concentrations of dioxins and furans (specifically TCDD and TCDF), as well as adsorbable organic halogens (such as chloroform) and chemical oxygen demand (COD). The standards represent a compromise that allow the substitution of Table 6.21 Toxicological characterization data for toluene RfD

RfC

LD50 (rats) LC50 (rats) LOAEL

0.08 mg/kg/day 5 mg/m3 5.5 g/kg Source: US EPA (2005).

17.4 g/m3 (6 h)

NOAEL PEL

446 mg/kg/ 128 mg/ 753.7 mg/ m3 day m3

228

Handbook of Pollution Prevention and Cleaner Production

chlorine dioxide for elemental chlorine in the bleaching process. A stronger set of standards, which would have required technologies that avoided the use of chlorine altogether, was not chosen. The Regional NOx Transport Rule (1998) requires 22 eastern states to institute measures to decrease their overall emissions of nitrogen oxides. The affected states were required to have controls on large industrial sources in place by 2003, and to meet overall NOx limits by 2007. Since individual states have considerable flexibility in devising their own specific implementation plans, the effect on pulp and paper facilities has varied considerably, depending on location. New standards for emissions of ozone precursors and fine particles affect some pulp and paper mills, particularly those impacting on ozone nonattainment areas. The Regional Haze Rule was finalized in 1999. This calls for states to establish goals and develop long-term strategies for improving visibility, particularly in national parks and wilderness areas. Some pulp and paper mills located in certain regions (such as mills directly upwind of sensitive areas) have been called upon to meet more stringent emissions limits for particulates and aerosol precursors. The Total Maximum Daily Load (TMDL) program defines the maximum amount of pollutants a given body of water can receive and still meet waterquality standards. Due to their high water use, pulp mills generally tend to be among the most significant impactors of the water bodies on which they are situated. State agencies are responsible for establishing effluent reduction levels for individual facilities. The reader can obtain details of each of these rules from the EPA website at http://www.epa.gov/owow/tmdl/index.html.

6.5 Emission factors The pulp and paper sector relies on the application of AP-42 published emission factors to estimate reported emissions (see Chapter 4 for an explanation of emission factors and the AP-42 publication). In the AP-42 publication, emission factors are generally presented as a single value that is the mean of the emissions data set, with nondetects included at onehalf the method detection limit. A quality rating (A, B, C, D, or E) is assigned to each factor. Statistical tests are not used to identify possible outliers. A description of how factors for the emission unit were developed is usually available in a background information document covering types of emission units found in an industrial source category or subcategory, e.g. chemical wood pulping. These documents may or may not contain summaries of emission test data used to compute the average emission factor. Section 10.2, Chemical Wood Pulping, is the AP-42 publication relied upon by the sector for estimating emission sources. A problem with the information that

Sources of air emissions from pulp and paper mills

229

currently exists is that the data reported largely reflect emission testing done in the 1970s. There are placeholders for sections on pulp bleaching and papermaking. A supplement to this resource is the EPA’s electronic WebFIRE (http:// cfpub.epa.gov/oarweb/index.cfm?action¼fire.main) database, but this has a very limited amount of newer test information for some pulp and paper mill sources, with the most recent test reports being ca. 1990. Emission factors for industrial boilers are in AP-42 Chapter 1, and are reasonably up to date. Table 6.22 is a summary of the emission factors for the pulp and paper industry downloaded from the EPA’s WebFIRE library. In applying the emission factors reported in the table the reader should note the following column entries:     

Source – identifies the emission source. Pollutant – denotes the air pollutant. Method of control – indicates whether the emission factor was measured from a source that was uncontrolled or had a pollution control. Value – emission factor value in scientific notation. For example, a value of 1.2Eþ01 is the same as 12.0. Emission factor:  Unit – the unit that the emission factor is reported in.  Measure – the per-unit basis of the emission factor.  Material – the per-unit basis of material that the emission factor is reported for.  Action – the action under which the per-unit basis of the emission factor was measured. As an example, the first entry in the table is for the emission source ‘‘Digester relief and blow tank’’. The uncontrolled emission factor reported for methyl alcohol is 1.70 lb of methyl alcohol per ton of pulp processed.  EF quality – the EPA’s rating of the reported emission factor. Refer to Chapter 4 for an explanation of the EPA rating system.

6.6 Case studies The pulp and paper industry has previously and continues to contribute a significant environmental footprint that impacts on communities. The industry has struggled to control its environmental impacts on the whole to a greater extent than the wood-preserving sector. Despite significant gains over the past 30 years to reduce pollution, it continues to generate large emissions that place communities at risks. The following are brief case studies of environmental impacts and regulatory infractions.

6.6.1

International Paper Co., Jay, ME

International Paper Co. (IP) owns and operates the Androscoggin Mill in Jay, ME. In 1987, the workers of this mill went on strike for more than a year in order to protest worker health issues and other pollution issues. In July 1991, five criminal indictments were brought against the mill. The allegations included misrepresentation in its wastewater license application and the burning of unlicensed waste.

230

Table 6.22 Emission factors for pulp and paper Emission factor Source

Pollutanta

Sulfate (kraft) pulping Digester relief Methyl alcohol and blow tank Methyl ethyl ketone Washer/screens

Value

Unit

Measure

Material

Action

Uncontrolled

1.70Eþ00

lb

Tons

Pulp

Processed U

Uncontrolled

1.40E02

lb

Tons

Pulp

Processed D

Methyl ethyl ketone SOx

Uncontrolled Uncontrolled

2.70E02 1.00E02

lb lb

Tons Tons

Processed D Produced A

VOC

Uncontrolled

2.00E01

lb

Tons

Pulp Air-dried unbleached pulp Air-dried unbleached pulp

Methyl ethyl ketone

Uncontrolled

2.70E02

lb

Tons

Pulp

Processed D

Carbon monoxide

Uncontrolled

1.10Eþ01

lb

Tons

Produced

U

Chlorodibenzo-p-dioxin, chlorodibenzofurans, total Heptachlorodibenzop-dioxins, total

8.14E02 Electrostatic precipitator – high efficiency 2.05E03 Electrostatic precipitator – high efficiency

mg

Kilograms

Air-dried unbleached pulp Black liquor solids

Burned

U

mg

Kilograms

Black liquor solids

Burned

U

Produced

U

Handbook of Pollution Prevention and Cleaner Production

Multi-effect evaporator Recovery furnace/ direct contact evaporator

EF quality

Method of control

Hexachlorodibenzofurans, total Methyl ethyl ketone NOx

Octachlorodibenzop-dioxins, total Octachlorodibenzofurans, total Pentachlorodibenzop-dioxins, total Pentachlorodibenzofurans, total PM, filterable

Electrostatic 1.17E03 precipitator – high efficiency Uncontrolled 1.50E02 Uncontrolled 2.00Eþ00

Electrostatic 4.20E03 precipitator – high efficiency Electrostatic 3.45E04 precipitator – high efficiency Miscellaneous 3.80E04 control devices

mg

Kilograms

mg

Burned

U

Megagrams Air-dried unbleached pulp Kilograms Black liquor solids

Produced

U

Burned

U

lb lb

Tons Tons

Processed D Produced U

mg

Kilograms

Pulp Air-dried unbleached pulp Black liquor solids

Burned

U

mg

Kilograms

Black liquor solids

Burned

U

mg

Megagrams Air-dried unbleached pulp Kilograms Black liquor solids

Produced

U

Burned

U

Tons

Produced

U

mg

< 9.900E4 mg Electrostatic precipitator – high efficiency Uncontrolled 1.80Eþ02 lb

Black liquor solids

Air-dried unbleached pulp

231

Continued

Sources of air emissions from pulp and paper mills

Heptachlorodibenzofurans, Electrostatic 1.05E03 total precipitator – high efficiency HexachlorodibenzoElectrostatic 1.10E03 p-dioxins, total precipitator

232

Table 6.22 Emission factors for pulp and paperdcont’d Emission factor Source

Unit

Measure

Material

Action

EF quality

Electrostatic precipitator – medium efficiency Venturi scrubber

2.00Eþ00

lb

Tons

Air-dried unbleached pulp

Produced

A

4.80Eþ01

lb

Tons

Produced

A

PM, filterable

Scrubber

3.000E0– 1.500E1

lb

Tons

Air-dried unbleached pulp Air-dried unbleached pulp

Produced

A

PM10, filterable

Uncontrolled

1.68Eþ02

lb

Tons

Produced

U

PM2.5, filterable

Uncontrolled

1.50Eþ02

lb

Tons

Air-dried unbleached pulp Air-dried unbleached pulp

Produced

C

Carbon monoxide

Electrostatic precipitator Uncontrolled

1.91Eþ00

lb

Tons

Burned

U

1.00Eþ00

lb

Tons

Produced

U

Wet scrubber – medium efficiency

2.09E01

lb

Tons

Black liquor solids Air-dried unbleached pulp Black liquor solids

Burned

U

PM, filterable

PM, filterable

Smelt dissolving tank

NOx

NOx

Handbook of Pollution Prevention and Cleaner Production

Value

Pollutanta

Method of control

Electrostatic precipitator Uncontrolled

1.28Eþ00

lb

Tons

7.00Eþ00

lb

Tons

Wet scrubber – medium efficiency Venturi scrubber

1.84E01

lb

Tons

2.00E01

lb

Tons

PM, filterable

Packed scrubber

1.00Eþ00

lb

Tons

PM10, filterable

Uncontrolled

6.20Eþ00

lb

Tons

PM10, filterable

Venturi scrubber

1.80E01

lb

Tons

PM10, filterable

Packed scrubber 9.50E01

lb

Tons

PM2.5, filterable

Uncontrolled

5.10Eþ00

lb

Tons

PM2.5, filterable

Venturi scrubber

1.60E01

lb

Tons

PM, filterable

PM, filterable

PM, filterable

Black liquor solids Air-dried unbleached pulp Black liquor solids

Burned

U

Produced

U

Burned

U

Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp

Produced

A

Produced

A

Produced

U

Produced

C

Produced

C

Produced

C

Produced

C

233

Continued

Sources of air emissions from pulp and paper mills

NOx

234

Table 6.22 Emission factors for pulp and paperdcont’d Emission factor Source

Pollutanta

Unit

Measure

Material

Action

EF quality

Air-dried unbleached pulp Black liquor solids

Produced

C

Burned

U

Black liquor solids Air-dried unbleached pulp Black liquor solids

Burned

U

Produced

U

Burned

U

Black liquor solids Air-dried unbleached pulp

Burned

U

Produced

U

Air-dried unbleached pulp

Produced

U

Packed scrubber

8.50E01

lb

Tons

Sulfur dioxide

Wet scrubber – medium efficiency Electrostatic precipitator Uncontrolled

8.04E04

lb

Tons

2.99E03

lb

Tons

2.00E01

lb

Tons

1.14E01

lb

Tons

1.38E02

lb

Tons

VOCs

Wet scrubber – medium efficiency Electrostatic precipitator Uncontrolled

1.60E01

lb

Tons

Acetaldehyde

Uncontrolled

7.40E05

lb

Tons

SOx

TOCs

TOCs

Handbook of Pollution Prevention and Cleaner Production

Value

PM2.5, filterable

Sulfur dioxide

Lime kiln

Method of control

Uncontrolled

4.68E07

lb

Tons

Beryllium

Uncontrolled

7.80E06

lb

Tons

Cadmium

Uncontrolled

2.02E06

lb

Tons

Carbon monoxide

Uncontrolled

1.00E01

lb

Tons

Chromium

Uncontrolled

4.66E04

lb

Tons

Copper

Uncontrolled

2.80E05

lb

Tons

Fluoranthene

Uncontrolled

<3.480E6 lb

Tons

Heptachlorodibenzofurans, total

Uncontrolled

1.66E10

lb

Tons

Hexachlorodibenzofurans, total

Uncontrolled

8.40E11

lb

Tons

Hydrogen chloride

Uncontrolled

2.20E06

lb

Tons

Produced

U

Produced

U

Produced

U

Produced

U

Produced

U

Produced

U

Produced

U

Produced

U

Produced

U

Produced

U 235

Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp

Sources of air emissions from pulp and paper mills

Arsenic

Continued

236

Table 6.22 Emission factors for pulp and paperdcont’d Emission factor Source

Value

Unit

Measure

Material

Action

EF quality

Lead

Uncontrolled

1.09E04

lb

Tons

Produced

U

Manganese

Uncontrolled

3.50E05

lb

Tons

Produced

U

Mercury

Uncontrolled

2.90E07

lb

Tons

Produced

U

Nickel

Uncontrolled

1.29E04

lb

Tons

Produced

U

NOx

Uncontrolled

2.80Eþ00

lb

Tons

Produced

U

Octachlorodibenzop-dioxins, total

Uncontrolled

1.75E09

lb

Tons

Produced

U

Pentachlorodibenzofurans, total

Uncontrolled

1.07E10

lb

Tons

Produced

U

PM, filterable

Uncontrolled

5.60Eþ01

lb

Tons

Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp

Produced

U

Handbook of Pollution Prevention and Cleaner Production

Pollutanta

Method of control

5.00E01

lb

Tons

Air-dried unbleached pulp

Produced

A

5.00E01

lb

Tons

Produced

A

PM10, filterable

Uncontrolled

9.40Eþ00

lb

Tons

Produced

U

PM10, filterable

lb

Tons

Produced

C

PM10, filterable

Electrostatic 4.40E01 precipitator – medium efficiency Venturi scrubber 4.90E01

Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp

lb

Tons

Produced

C

PM2.5, filterable

Uncontrolled

5.90Eþ00

lb

Tons

Produced

C

PM2.5, filterable

Electrostatic precipitator – medium efficiency Venturi scrubber

4.20E01

lb

Tons

Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp

Produced

C

4.80E01

lb

Tons

Air-dried unbleached pulp

Produced

C

PM, filterable

PM2.5, filterable

Sources of air emissions from pulp and paper mills

Electrostatic precipitator – medium efficiency Venturi scrubber

PM, filterable

Continued 237

238

Table 6.22 Emission factors for pulp and paperdcont’d Emission factor Source

Value

Unit

Measure

Material

Action

EF quality

Polychlorinated dibenzo-pdioxins, total

Uncontrolled

2.84E09

lb

Tons

Produced

U

Polychlorinated dibenzofurans, total

Uncontrolled

8.46E10

lb

Tons

Produced

U

Selenium

Uncontrolled

4.04E07

lb

Tons

Produced

U

SOx

Uncontrolled

3.00E01

lb

Tons

Produced

A

2,3,7,8Tetrachlorodibenzofuran

Uncontrolled

< 0.000E0 lb

Tons

Produced

U

Tetrachlorodibenzofurans, total

Uncontrolled

2.54E10

lb

Tons

Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp

Produced

U

VOCs

Uncontrolled

2.50E01

lb

Tons

Produced

U

Pollutanta

Air-dried unbleached pulp

Handbook of Pollution Prevention and Cleaner Production

Method of control

Fluid-bed calciner

Liquor oxidation tower

Recovery furnace/ indirect contact evaporator

Methyl ethyl ketone

Uncontrolled

9.00E03

lb

Tons

Pulp

Processed D

VOCs

Uncontrolled

7.00E02

lb

Tons

Air-dried unbleached pulp

Produced

U

NOx

Uncontrolled

2.80Eþ00

lb

Tons

Produced

U

PM10, filterable

Uncontrolled

5.04Eþ01

lb

Tons

Produced

U

SOx

Uncontrolled

3.00E01

lb

Tons

Produced

U

VOCs

Uncontrolled

2.50E01

lb

Tons

Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp

Produced

U

Methyl ethyl ketone

Uncontrolled

1.00E02

lb

Tons

Pulp

Processed D

SOx

Uncontrolled

2.00E02

lb

Tons

Produced

U

VOCs

Uncontrolled

4.50E01

lb

Tons

Air-dried unbleached pulp Air-dried unbleached pulp

Produced

U

Carbon monoxide

Uncontrolled

1.10Eþ01

lb

Tons

Air-dried unbleached pulp

Produced

U

239

Continued

Sources of air emissions from pulp and paper mills

Turpentine condenser

240

Table 6.22 Emission factors for pulp and paperdcont’d Emission factor Source

Value

Unit

Measure

Material

Action

EF quality

NOx

Uncontrolled

1.90Eþ00

lb

Tons

Produced

U

PM, filterable

Uncontrolled

2.30Eþ02

lb

Tons

Produced

U

PM, filterable

Electrostatic precipitator – medium efficiency Uncontrolled

2.00Eþ00

lb

Tons

Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp

Produced

A

2.30Eþ02

lb

Tons

Produced

U

Electrostatic precipitator – medium efficiency Uncontrolled

1.50Eþ00

lb

Tons

Air-dried unbleached pulp Air-dried unbleached pulp

Produced

C

1.80Eþ02

lb

Tons

Produced

C

Electrostatic precipitator – medium efficiency

1.30Eþ00

lb

Tons

Air-dried unbleached pulp Air-dried unbleached pulp

Produced

C

PM10, filterable

PM10, filterable

PM2.5, filterable

PM2.5, filterable

Handbook of Pollution Prevention and Cleaner Production

Pollutanta

Method of control

8.00E01

lb

Tons

Air-dried unbleached pulp

Acetaldehyde

Uncontrolled

3.61E04

kg

Acetaldehyde

Uncontrolled

5.47E06

kg

Acetaldehyde

Uncontrolled

7.01E06

kg

Benzene

Uncontrolled

9.12E05

kg

Carbon tetrachloride

Uncontrolled

4.07E04

kg

Chlorine

Uncontrolled

1.07E06

kg

Chloroform

Uncontrolled

9.25E03

kg

Dichloromethane

Uncontrolled

6.91E05

kg

Ethylene dibromide

Uncontrolled

<2.010E 04

kg

Megagrams Air-dried bleached pulp Megagrams Air-dried bleached pulp Megagrams Air-dried bleached pulp Megagrams Air-dried bleached pulp Megagrams Air-dried bleached pulp Megagrams Air-dried bleached pulp Megagrams Air-dried bleached pulp Megagrams Air-dried bleached pulp Megagrams Air-dried bleached pulp

Produced

U

Produced

U

Produced

U

Produced

U

Produced

U

Produced

U

Produced

U

Produced

U

Produced

U

Produced

U 241

Uncontrolled

Sources of air emissions from pulp and paper mills

Other not classified

VOCs

Continued

242

Table 6.22 Emission factors for pulp and paperdcont’d Emission factor Source

EF quality

Megagrams Air-dried bleached pulp Megagrams Air-dried bleached pulp Megagrams Air-dried bleached pulp Megagrams Air-dried bleached pulp Tons Pulp Megagrams Air-dried bleached pulp Megagrams Air-dried bleached pulp

Produced

U

Produced

U

Produced

U

Produced

U

Produced

U

Tons

Produced

C

Value

Unit

Measure

Formaldehyde

Uncontrolled

3.23E03

kg

Methyl alcohol

Uncontrolled

2.68E03

kg

Methyl alcohol

Uncontrolled

3.91Eþ00

kg

Methyl alcohol

Uncontrolled

8.44E04

kg

Methyl ethyl ketone 1,1,1-Trichloroethane

Uncontrolled Uncontrolled

3.00E03 1.57E04

lb kg

Trichloroethylene

Uncontrolled

3.32E05

kg

SOx

Uncontrolled

4.00Eþ01

lb

Material

Air-dried unbleached pulp

Processed D Produced U

Handbook of Pollution Prevention and Cleaner Production

Sulfite pulping Digester/blow pit/ dump tank: all bases except calcium

Action

Pollutanta

Method of control

SOx

Uncontrolled

6.70Eþ01

lb

Tons

Air-dried unbleached pulp

Produced

C

Digester/blow pit/ dump tank: MgO with process change Digester/blow pit/ dump tank: NH3 with process change

SOx

Uncontrolled

2.00E01

lb

Tons

Air-dried unbleached pulp

Produced

B

SOx

Uncontrolled

4.00E01

lb

Tons

Air-dried unbleached pulp

Produced

B

Digester/blow pit/ dump tank: Na with process change

SOx

Uncontrolled

2.00Eþ00

lb

Tons

Air-dried unbleached pulp

Produced

C

Recovery system: MgO

PM, filterable

Uncontrolled

2.00Eþ00

lb

Tons

Air-dried unbleached pulp

Produced

U

SOx

Uncontrolled

9.00Eþ00

lb

Tons

Air-dried unbleached pulp

Produced

U

PM, filterable

Uncontrolled

7.00E01

lb

Tons

Air-dried unbleached pulp

Produced

U

SOx

Uncontrolled

7.00Eþ00

lb

Tons

Air-dried unbleached pulp

Produced

U

Recovery system: NH3

243

Continued

Sources of air emissions from pulp and paper mills

Digester/blow pit/ dump tank: calcium

244

Table 6.22 Emission factors for pulp and paperdcont’d Emission factor Source

Value

Unit

Measure

Material

Action

EF quality

Uncontrolled

4.00Eþ00

lb

Tons

Produced

U

SOx

Uncontrolled

2.00Eþ00

lb

Tons

Air-dried unbleached pulp Air-dried unbleached pulp

Produced

U

SOx

Uncontrolled

3.00E01

lb

Tons

Air-dried unbleached pulp

Produced

U

VOCs

Uncontrolled

3.50Eþ00

lb

Tons

Air-dried unbleached pulp

Produced

U

SOx

Uncontrolled

2.00E01

lb

Tons

Air-dried unbleached pulp

Produced

U

VOCs

Uncontrolled

3.50Eþ00

lb

Tons

Air-dried unbleached pulp

Produced

U

SOx

Uncontrolled

8.00Eþ00

lb

Tons

Air-dried unbleached pulp

Produced

U

Pollutanta

Recovery system: NaPM, filterable

Acid plant: NH3

Acid plant: Na

Acid plant: Ca

Handbook of Pollution Prevention and Cleaner Production

Method of control

Uncontrolled

3.50Eþ00

lb

Tons

SOx

Uncontrolled

1.20Eþ01

lb

Tons

Neutral sulfite semichemical pulping Digester/blow pit/ SOx dump tank

Uncontrolled

4.00Eþ00

lb

Tons

Fluid-bed reactor

NOx

Uncontrolled

1.60Eþ00

lb

Tons

PM10, filterable

Uncontrolled

2.82Eþ02

lb

Tons

VOCs

Uncontrolled

2.50E01

lb

Tons

SOx

Uncontrolled

2.00Eþ01

lb

Tons

Knotters/washers/ screens, etc.

Sulfur burner/ absorbers

Air-dried unbleached pulp Air-dried unbleached pulp

Produced

U

Produced

D

Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp Air-dried unbleached pulp

Produced

U

Produced

U

Produced

U

Produced

U

Air-dried unbleached pulp

Produced

U

Sources of air emissions from pulp and paper mills

VOCs

a

NOx, nitrogen oxides; PM, particulate matter; SOx, sulfur oxides; TOCs, total organic compounds; VOCs, volatile organic compounds. Source: US EPA WebFire.

245

246

Handbook of Pollution Prevention and Cleaner Production

The mill’s ability to continue operating was also at risk, because its landfill was approaching capacity, and permits and authorization for expansion looked unlikely. IP pleaded guilty to five felony counts for illegally storing and treating hazardous waste. Their total payout was $2.2 million in 1991. IP decided to hire multiple corporate-level employees in order to reinvent the mill’s business approach and turn the Androscoggin Mill into IP’s best environmental performer. Original plans to meet compliance were expanded into aggressive anti-pollution projects with cooperation from the Environmental Protection Agencies of the USA and the state of Maine. The main goal of these projects was to ‘‘close the loop’’ and reach sustainability for the mill. Many of the improvements to the mill started when President George H.W. Bush established the President’s Commission on Environmental Quality (PCEQ) to seek advice from the private sector on environmental issues (PCEQ, 1990). David Critchfield, IP’s director of regulatory affairs and recycling, attended on behalf of IP’s chief executive officer. The commission urged companies to integrate pollution prevention principles into corporate environmental programs, test new strategies, and share results. Recommendations relevant to Androscoggin Mill included:   

pursue pollution prevention projects; form public participation groups in communities where they operated and become more open to community involvement and input; take one facility and develop it into an environmental model, from which other facilities can learn.

Many companies adopted the third recommendation and chose to improve a facility that was already performing well, but IP decided to revamp the troubled Androscoggin Mill, and make a conscious effort to turn it into its best. The community also helped push IP towards improving Androscoggin Mill. As a result of citizens’ poor regard of mill environmental performance, the town of Jay instituted its own environmental ordinance, subjecting the mill to more restrictive local regulations along with those already established by the state and federal governments. Additional regulations added by this town ordinance included the installation of a regenerative thermal oxidizer, in order to reduce odorous chemical emissions, and more monitoring wells for the mill’s landfill. In a large pulp and paper mill, management of complex environmental programs requires the support and participation of workers and managers. This was difficult in an environment in which workplace communications were still poor after the strike and mill environmental infractions remained common. In fact, the recovery boilers were averaging 56 opacity (an optical measure of particulate emissions) incidents a year. In order to simplify and unify the process, each member of the boiler staff was given control over a specific section of equipment. As each came to know a section well, they developed the skill to maintain proper conditions, and therefore reduce emissions and infractions. External recognition, such as the IP Corporate Award for Environmental Excellence, maintained employee motivation and morale.

Sources of air emissions from pulp and paper mills

247

IP and the many environmental teams that it works with made improvements to many different sections of the mill. Biological oxygen demand (BOD) was reduced by introducing aerators into the wastewater treatment system. Mercury in the river was cut down significantly by switching to more responsible suppliers. For example, the mill decided to buy uncontaminated sulfuric acid from a nickel smelter instead of a lead smelter. After a few years the mercury content of the river dropped from 19.2 to 3.4 ppt. The mill switched from chlorine to chlorine dioxide in order to create an ECF pulp and to reduce dioxin and furan emissions. Discontinuing the use of elemental chlorine also reduced the risk of accidental release and employee exposure during handling and transport. Table 6.23 shows examples of how the Androscoggin Mill’s emissions were reduced. The Androscoggin Mill also took steps to reduce its solid and hazardous waste. In 1988, the mill operated an on-site landfill that averaged 1643 cubic yards of new waste a day, and was close to capacity. Increased efforts in recycling, pollution prevention, incineration, and beneficial reuse resulted in an average landfill rate in 2001 of 150 cubic yards per day. Hazardous waste was cut from 60,000 pounds in 1990 to 3260 pounds in 2000. Mill programs that helped achieve these reductions include:     



recycling wood, metals, and paper; compacting nonrecyclable paper into burnable pellets; improving lime-kiln operations to allow firing of all lime mud produced; selling flume grit to a contractor that processed it into landscape material (similar to peat or perlite used for potting media and erosion control); burning bark and sludge and incorporating the ash into AshCrete (a product developed by Stephen Groves – it is a cheap substitute for low-grade concrete, and is good for dikes, berms, and landfill control), a product developed at the mill; incorporating green liquor dregs into AshCrete.

Another interesting change that occurred at the Androscoggin Mill was the development of a tight industrial ecosystem. Several other companies have Table 6.23 Mill pollution prevention example Pollutant

Year

Discharges

Dioxin (2,3,7,8-TCDD)

1988 1996

88 pg/l Nondetecta

Furan (2,3,7,8-TCDF)

1988 1997

420 pg/l Nondetect

AOXb

1994 2000

1.44 lb/ton bleached pulp/day 0.52 lb/ton bleached pulp/day

a

Nondetect means less than 10 pg/l. AOX denotes adsorbable organic halides, chlorine-containing by-products formed during bleaching. Source: Hill et al. (2002). b

248

Handbook of Pollution Prevention and Cleaner Production

located facilities around the mill to take advantage of by-products and market opportunities. Some of these companies include the following: 

 

Specialty Minerals Inc. produces precipitated calcium carbonate (PCC). Specialty Minerals needed a source of carbon dioxide and an outlet for PCC, so they set up operations near the mill in 1997 using carbon dioxide emissions from a lime kiln. In return, the mill buys PCC at an attractive price and eliminates transportation costs. AshCrete production facilities. Androscoggin Energy is a natural-gas-burning facility, generating electricity with high-temperature steam (sold off-site) and selling low-temperature steam to meet a portion of the mill’s needs.

International Paper followed the PCEQ’s recommendation and developed a Public Advisory Committee (PAC). The PAC was founded in 1992 with its mission defined as to ‘‘. help identify environmental issues the Androscoggin Mill must address, and proactively assist in choosing the options. This will be accomplished by developing trust and respect for each other.’’ By 2000, the members of the PAC expanded that mission to ‘‘. act as a public board to identify and respond to the environmental, social, economic, and community issues that the Androscoggin Mill must address, and proactively assist in choosing sustainable options.’’ Over time the PAC and IP became respectful partners, both working to develop a safe, sustainable community. This case study shows that community involvement is an important factor in reforming pollution sources. Without pressure from the community, the operating body will have less incentive to comply with local standards. As seen from this case here, an active, constructive PAC, along with motivated corporate officials, can lead to drastic environmental performance improvements (Hill et al., 2002).

6.6.2

International Paper Co., Ticonderoga, NY

International Paper is not always as responsible as it was for the Androscoggin Mill in Jay, ME. Its plant in Ticonderoga, NY has been fined and sued numerous times for its poor, irresponsible environmental practices. The following is a timeline of law suits and violations that the plant has endured:  



 

1926 – International Paper Co. purchases a pulp mill that has been located in Ticonderoga since the late nineteenth century (Kovach, 1970). 1965 – the New York State Department of Environmental Conservation (NYSDEC) demands that IP constructs treatment systems for its plant. IP opts to build a new plant (the current facility) 10 miles north of the previous plant (Kovach, 1970). 1968–1970 – IP and the state of Vermont dispute over a 300-acre mass of sludge (20 feet thick in places) IP has deposited on the bed of Lake Champlain. IP denies that the sludge bed (on the lake’s floor, at the end of the Ticonderoga Cree, where the mill dumps its effluent) is the responsibility of IP (Kovach, 1970). 1970 – IP opens its current mill (Kovach, 1970). 1978 – Vermont land owners file a class-action suit against IP for damaging their property values (Barna, 1989).

Sources of air emissions from pulp and paper mills

   

   







 



 

249

1981 – more than 3 million gallons of fuel oil overflow a storage tank and run into the lake (Ellis, 1989). 1982 – nearly two million gallons of wastewater, only partially treated, is discharged into the lake (Ellis, 1989). 1983 – eight tons of dioxin-laced sludge from IP’s landfill breach a container dike and come to rest near a creek that runs into Lake Champlain (Ellis, 1989). 1986 – a landfill leachate collection pond overflows for longer than 4 days, spilling half a million gallons of liquid landfill drainage into a creek that runs into the lake (Ellis, 1989). 1987 – IP under-reports its chloroform emissions by 90%, claiming an emission of 4700 pounds instead of 47,000 pounds (Norton, 1989). 1988 – IP again emits 47,000 pounds of chloroform, making it the largest chloroform source in the state of New York (Norton, 1989). 1989 – IP offers Vermont land owners $5 million to drop their 1978 class-action suit. IP admits to no wrong doing (Barna, 1989) 1989 – IP Ticonderoga Mill manager R. Fred Chasse, in a guest editorial in the Burlington Free Press, points to incineration as the nation’s number one source of dioxin (Chasse, 1989). 1990 – a researcher for the Vermont Transportation Agency’s materials and research lab finds a new sludge bed, just north of IP’s diffuser pipe. The researcher, Richard Haupt, says the volume of sludge would cover a football field to a depth of 18 feet (Barna, 1990). 1990 – a 2-mile pipeline carrying leachate from one of the mill’s two landfills bursts, sending a million gallons of effluent into wetlands adjacent to Lake Champlain. An employee of the plant then breaks a beaver dam that was containing the waste, and it spills into Lake Champlain. IP is fined $65,000 by the state (Pulp and Paper Magazine, 1991). (Vermont officials only learn about this spill after Senator Elizabeth Ready’s constituents call her to report strange activities by IP along the lakeshore.) March 1991 – IP experiences a liquid waste spill. Company officials estimate the size of the spill as 300 gallons. Union representatives say more than 10,000 gallons were spilled (Maxwell, 1991). November 1991 – IP spills half a million gallons of partially treated wastes. A quarter of a million gallons flow into Lake Champlain (Barna, 1991). 1992 – in sworn testimony before a Senate Subcommittee on Labor, Stephen Perry, representing the United Brotherhood of Carpenters and the United Paperworkers International Union, said: ‘‘At Ticonderoga, New York, chlorine and chlorine dioxide spills were so commonplace that even the complaint officer was gassed during the inspection’’ (Senate Subcommittee, 1992). 1993 – the EPA fines IP $32,000 for violating the federal Right-to-Know law. The EPA charged IP with failing to notify the proper agencies following an accidental air release of 88 pounds of chlorine from Ticonderoga in July 1990 (PR Newswire, 1993). 1994 – IP is fined $175,000 by New York State Department of Environmental Conservation (NYSDEC) for air-quality permit violations. 1997 – IP burns 6 tons of tires in its power boiler to test their use as an alternative fuel. Neither IP nor NYSDEC officials notify environmental regulators in Vermont. The test burn comes to light as a result of inquiries made by VPIRG (Vermont Public Interest and Research Group) staffers (VPIRG, 1998).

250





Handbook of Pollution Prevention and Cleaner Production

2003 – IP officials from the Ticonderoga plant declare that no test data were taken at the 1997 test burn of tires when questioned at a public meeting in Middlebury, VT. Vermont officials find test data submitted to the NYSDEC that indicate mercury levels rose 200% and zinc levels rose 500% in fly ash. 2005 – IP resubmits a permit to test burn tires. The permit is found to be incomplete by the NYSDEC. IP officials state they will resubmit the permit and hope to test burn tires in the fall.

As you can see, IP has been extremely irresponsible in the past. Misreporting and trying to cover up spills are common practices at Ticonderoga. These actions will no longer be tolerated. If spills occur they must be dealt with properly and honestly. It is important that IP realizes that lying and cheating are no longer going to work. IP needs to step up as one of the world’s largest paper producers and lead by example. Without sustainability the paper industry is doomed, and irresponsible actions, such as the timeline discussed above, have to be stopped immediately.

6.6.3

Kimberly-Clark Corp., Everett, WA

International Paper is not the only paper company with environmental infractions. The sulfite mill in Everett, WA operated by Kimberly-Clark Corp. (K-C) was fined in 2000 for repeatedly discharging excess amounts of pollution into Port Gardner Bay. The Everett mill exceeded the plant’s permitted limits on 14 August and 19 September 2000 by 12,000 and 4600 pounds respectively. The state Department of Ecology fined the plant $20,000 for these infractions. This was not the first time the plant was fined. In December 1998, the ecology department fined K-C $6000 for suspended solids infractions. Carol Kraege, who manages the Department of Ecology’s industrial section, said: ‘‘KimberlyClark has continued to have problems with processing its waste sludge. The company also has had a history of violations for suspended solids.’’ According to the Department of Ecology, the Everett mill also violated pH limits outlined in its water-quality permit (Puget Sound Business Journal, 2000). Carol Kraege also said: ‘‘We hope this penalty will serve as a deterrent against additional permit violations.’’ Although Kimberly-Clark doesn’t want fines like this, $20,000 doesn’t make a scratch in K-C’s earnings. In 2008, KimberlyClark’s net earnings were nearly $20 billion (Kimberly-Clark, 2008). If the Department of Ecology wants to get their point across, then they need to inflate the penalties that infractions such as these induce. Multimillion dollar or exponentially increasing fines need to be implemented in order to stop repeat offenders. Each violation makes a difference to the overall environment, and huge corporations should not be allowed any leeway.

6.6.4

Irving Pulp and Paper, St John mill

On 8 February 2007, Irving Pulp and Paper’s St John mill released black liquor into the St John River. Irving Pulp and Paper pleaded guilty on 13 February in a New Brunswick provincial court for violating the Fisheries Act. The penalties

Sources of air emissions from pulp and paper mills

251

for this violation totaled $37,000. The money from the fine was divided between two conservationist organizations. One of those organizations was nonprofit, Atlantic Coastal Action Program (ACAP). This case study shows us that spills and infractions are still happening. Efforts must remain strong in order to eliminate spills altogether (CBC, 2009).

6.6.5

Packaging Corporation of America, Tomahawk, WI

Mill violations are not always related to the environment. Paper and pulp plants have to maintain a safe workplace for their employees. The Packaging Corporation of America’s (PCA) Tomahawk mill failed to provide this safe environment. On Tuesday, 29 July 2008, three mill workers were killed when a pulp storage tank exploded. The three men were performing maintenance on the tank used to hold recycled fibers. The explosion may have been caused when PCA broke the rules by allowing welding near explosive material. Brad Mitchell, a spokesman for the US Labor Department, says one citation alleges supervisors did not consider certain safety risks before allowing the welding to start. ‘‘Maintenance supervisors reviewing and authorizing a safe work permit did not include potential buildup of flammable gas in their consideration,’’ he said. The OSHA fined PCA $22,000 for the violations (Lehman, 2009). There is a chance that this explosion could have been prevented, if the Tomahawk mill had put more time and focus into safety. Three citations were given to the mill in 2006 and 2007. The most recent violation was last year when the company was cited, but not fined, for failing to keep an aisle cleared. PCA was cited twice in 2006 and paid nearly $900 to settle allegations that machines lacked proper safety guards. The OSHA also cited the company’s plants in Burlington and Colby in 2001 for safety violations. PCA should not allow these safety problems to occur. They are a very large company, producing more than 572 million tons and grossing $2.3 billion annually. A company with resources like this should have fully functional safety equipment. It is up to the OSHA and other organizations to put more pressure on companies that do not have safe work environments. Fining a $2.3 billion a year corporation $900, or even $20,000, is not going to change anything. Serious penalties need to be handed out for safety violations in order to prevent fatalities like the three that occurred in Wisconsin (Associated Press, 2009).

6.6.6

Fort James Operating Company Inc., Pennington, AL

On 16 January 2002, contract employees working to replace a pipe rack in the chemical wash area of the plant were exposed to high concentrations of hydrogen sulfide. The exposure occurred when sulfuric acid and wastewater were released simultaneously into the sewer system. The gas escaped through a manhole cover, killing two workers and injuring eight others. ‘‘Adding to the tragedy of these deaths and injuries is the fact that they could have been avoided,’’ said Lana Graves, the OSHA’s mobile area director. ‘‘Anticipating and preventing accidents is key to a safe workplace.’’

252

Handbook of Pollution Prevention and Cleaner Production

Fort James Operating Co. received a $70,000 willful citation (given when the department finds an employer intentionally or knowingly violated rules or knew that a violation was occurring and was plainly indifferent to correcting it) for failing to protect workers by installing engineering devices to control the addition of chemicals into the sewer system and to prevent accidental releases. The OSHA tacked on three additional citations totaling $21,000 for failing to tell contractors and their employees of the potential for hazardous chemicals in the area, provide chemical detection monitors, and install an alarm system to alert employees of a hazardous gas release (Smith, 2002).

6.6.7

Longview Fibre Co., Paper and Packaging Longview, WA

The Washington Department of Labor and Industries (L&I) initiated an investigation on 2 January 2004 following the death of 38-year-old Mark Greenland, an employee who was caught inside a paper cutter when another employee inadvertently started it up. The investigation led to the company being cited for three willful violations and one serious-repeat violation. Citations were issued for failure to:    

establish and implement procedures for deactivating and locking out equipment to prevent unexpected startup of machinery, and train employees on those procedures; provide retraining when procedures change or equipment is modified or when employees are assigned new job duties; conduct periodic inspections of energy control procedures; ensure that employees were following proper lock-out procedures.

The investigation held by the L&I found repeated company disregard for known lock-out/tag-out procedures and training, as evidenced by an injury in 1998 and a close call in 1999. Both of these incidents occurred on the same machine as the fatal injury in January 2004. Longview Fibre has been cited in the past for 11 serious violations related to lock-out/tag-out procedures. Penalties for the four citations totaled $203,100 (Smith, 2004). Several years later a settlement was reached by L&I, Longview Fibre, and the Association of Western Pulp and Paper Workers Union, Local 153. The settlement focuses on significant changes at the company, and a substantial commitment from the new owner and union to work cooperatively to keep the workplace safe. The terms of the agreement include the following:     

L&I will modify the violations from ‘‘willful’’ and ‘‘serious-repeat’’ to ‘‘serious’’. Longview Fibre agrees to pay the penalties, abate the cited violations, and dismiss its appeal of another citation issued in January 2007. The company agrees to establish a schedule for conducting comprehensive safety and health consultation, with the union fully involved. The company will work toward acceptance into the Voluntary Protection Program (VPP), an L&I program for achieving excellence in workplace safety and health. L&I will not schedule the company for inspection for 1 year, although inspections may be initiated by complaints, injuries, or a death.

Sources of air emissions from pulp and paper mills

253

In addition, Longview Fibre set up a $50,000 education fund for the daughters of the deceased (OHS Magazine, 2007).

6.6.8

International Paper Co., Vicksburg, MS

An explosion occurred on 3 May 2008 in an International Paper Co. mill in Vicksburg, MS. The explosion killed one person and injured 17 others. The OSHA fined IP $77,000 for a willful violation and a serious violation. The willful violation was for failing to start the recovery boiler with adequate steam and not developing safe procedures to start up the boiler when the primary power boiler is off-line. The serious violation was for failing to have written procedures to determine that an adequate amount of odorant was being added to the natural gas supply line coming into the power plant, an indicator that the highly volatile gas is present. Marcus Christopher Broome was killed in the blast and the 17 injured were contract workers who have never been identified by IP. Approximately 400 people were present at the mill at the time of the blast, including IP’s 306 regular employees (Associated Press, 2008).

References Aksoy, M., 1991. Hematotoxicity, Leukemogenicity and Carcinogenicity of Chronic Exposure to Benzene. In: Arinc, E., Schenkman, J.B., Hodgson, E. (Eds), Molecular Aspects of Monooxygenases and Bioactivation of Toxic Compounds. Plenum Press, New York, pp. 415–434. Aksoy, M., Erdem, S., Dincol, G., 1974. Leukemia in shoe workers exposed chronically to benzene. Blood Dec 44 (6), 837–841. Albert, R.E., Sellakumar, A.R., Laskin, S., Kuschner, M., Nelson, N., Snyder, C.A., 1982. Gaseous Formaldehyde and Hydrogen Chloride Induction of Nasal Cancer in the Rat. Journal of the National Cancer Institute 68 (4), 597–603. Ameno, K., Fuke, C., Ameno, S., et al., 1989. A Fatal Case of Oral Ingestion of Toluene. Forensic Science International 41, 255–260. American Conference of Governmental Industrial Hygienists (ACGIH), 1991. Documentation of the Threshold Limit Values and Biological Exposure Indices, sixth ed. ACGIH, \Cincinnati, OH. Appleman, L.M., Woutersen, R.A., Feron, V.J., Hooftman, R.N., Notten, W.R.F., 1986. Effect of Variable versus Fixed Exposure Levels on the Toxicity of Acetaldehyde in Rats. Journal of Applied Toxicology 6 (5), 331–336. Argus Research Laboratories, 1997. Oral (Gavage) Developmental Toxicity Study of Phenol in Rats. Protocol number 916-011. Argus Research Laboratories, Horsham, PA. Associated Press, 2008. Feds Fine International Paper after Mississippi Mill Explosion. http://74.125.155.132/search?q¼cache:http://www.insurancejournal.com/news/ southeast/2008/11/06/95270.htm 6 November. Associated Press, 2009. OSHA Cited Mill Three Times Before Explosion: Three Killed in Tuesday Explosion in Tomahawk. NBC 4 Milwaukee, May; http://www. todaystmj4.com/news/local/45688662.html. Barna, E., 1989. IP in $5 Million Settlement. Valley Voice. 25 July.

254

Handbook of Pollution Prevention and Cleaner Production

Barna, E., 1990. Mill Discharge into Lake is Considerable. Valley Voice. 23 January. Barna, E., 1991. International Paper Debate Heats Up. Vermont Business Magazine. December. BOC Gases, 1996. MSDS – Methyl Mercaptan. The BOC Group Inc., October; http:// www.vngas.com/pdf/g239.pdf Bomski, H., Sobolweska, A., Strakowski, A., 1967. Toxic Damage of the Liver by Chloroform in Chemical Industrial Workers. As cited in US EPA (1994d). Arch Gewerbepathol Gewerbehyg 24, 127–134. Bond, G.G., Flores, G.H., Shellenberger, R.J., 1986. Nested case-control study of lung cancer among chemical workers. Am J Epidemoil. 124, 53–66. Brady, J.D., Legatski, L.K., 1977. Venturi Scrubbers. In: Cheremisinoff, P.N., Young, R.A. (Eds), Air Pollution Control and Design Handbook, Part 2. Marcel Dekker, New York. Burnett, W.W., King, E.G., Grace, M., Eng, P., Hall, W.F., 1977. Hydrogen Sulfide Poisoning: Review of 5 Years’ Experience. Canadian Medical Association Journal 117, 1277–1280. Callahan, M.A., Slimak, M.W., Bagel, N., et al., 1979. Water-related Environmental Fate of 129 Priority Pollutants, vol. II. EPA/440/4-79-029. US EPA, Office of Water Planning and Standards, Office of Water and Waste Management, Washington, DC. Campos, F.B., Lage, P.L., 2001. Modeling and Simulation of Direct Contact Evaporators. Brazilian Journal of Chemical Engineering July; http://www.scielo.br/scielo. php?pid¼S0104-66322001000300007&script¼sci_arttext Canadian Broadcasting Corporation (CBC), 2009. Irving Pulp and Paper Fined $37,000 for Violating Fisheries Act. CBCnews.ca, 13 February; http://www.cbc.ca/canada/ new-brunswick/story/2009/02/13/nb-irving-fine.html#socialcomments Canady, R., Crump, K., Feeley, M., Freijer, J., Kogevinas, M., Malisch, R., Verger, P., Wilson, J., Zeilmaker, M., 2001. Safety Evalution of Certain Food Additives and Contaminants. WHO Food Additives Series, INCHEM; http://www.inchem.org/ documents/jecfa/jecmono/v48je20.htm#2.2.1 Caravati, E.M., Bjerk, P.J., 1997. Acute Toluene Ingestion Toxicity. Annals of Emergency Medicine 30, 838–839. Chasse, F., 1989. Paper Mill is not Lake’s Largest Polluter. Burlington Free Press. 14 November. Cotton, F.A., Wilkinson, G., 1980. Advanced Organic Chemistry: A Comprehensive Text, fourth ed. John Wiley, New York, pp. 719–736. Dudley, H.C., Sweeny, T.K., Miller, J.W., 1942. Toxicology of Acrylonitrile (Vinyl Cyanide). II. Studies of Effects of Daily Inhalation. Journal of Industrial Hygiene and Toxicology 24 (9), 255–258. Elkins, H.B., 1959. The Chemistry of Industrial Toxicology, second ed. John Wiley, New York, pp. 89–90. Ellis, K., 1989. Lake Champlain. Burlington Free Press. 5 November. Energy Manager Training (EMT), 2008. Pulp and Paper; http://www.energy managertraining.com/pulp_paper/Pulp_paper_process.htmforests.org/forest_to_ paper.htm Exner-Freisfeld, H., Kronenberger, H., Meier-Sydow, J., et al., 1986. Intoxication from Bleaching with Sodium Chlorite. The Toxicology and Clinical Course [German with English abstract]. Dtsch. Med. Wochenschr. 111 (50), 1927–1930. Genium, 1992. Material Safety Data Sheet No. 53. Genium, Schenectady, NY.

Sources of air emissions from pulp and paper mills

255

Geyer, H.J., Scheuntert, I., Rapp, K., Kettrup, A., Korte, F., Greim, H., Rozman, K., 1990. Correlation Between Acute Toxicity of TCDD and Total Body Fat Content in Mammals. Toxicology 65, 97–107. Gilbert, F., Minn, C., Duncan, R., Wilkinson, J., 1990. Effects of Pentachlorophenol and Other Chemical Preservatives on the Health of Wood-treating Workers in Hawaii. Archives of Environmental Contamination and Toxicology 19 (4), 603–609. Gosselin, R.E., Smith, R.P., Hodge, H.C., 1984. Clinical Toxicology of Commercial Products, fifth ed. Williams and Wilkins, Baltimore, MD. Hathaway, G.J., Proctor, N.H., Hughes, J.P., Fischman, M.L., 1991. Proctor and Hughes’ Chemical Hazards of the Workplace, third ed. Van Nostrand Reinhold, New York. Hazardous Substances Data Bank (HSDB), 1998. National Library of Medicine. National Toxicology Information Program, Bethesda, MD. February. Hill, M., Saviello, T., Groves, S., 2002. The Greening of a Pulp and Paper Mill: International Paper’s Androscoggin Mill, Jay, Maine. Journal of Industrial Ecology 6 (1). https://courses.washington.edu/uconj540/Readings/Greening%20a%20paper% 20mill.pdf. Hormes, J.T., Filley, C.M., Rosenberg, N.L., 1986. Neurologic sequelae of chronic solvent vapor abuse. Neurology 36, 698–702. Huber, A.L., Loving, T.J., 1991. Fatal Asthma Attack After Inhaling Sulfur Fumes. Journal of the American Medical Association 266 (16), 2225. Hunnewell, J., Miller, N.R., 1998. Bilateral Internuclear Ophthalmoplegia Related to Chronic Toluene Abuse. Journal of Neuroophthalmology 18, 277–280. Hutter, G.M., 1997. Reference Data Sheet on Air Pollution Control Devices. Meridian Engineering and Technology, May; http://www.meridianeng.com/airpolld.html Idaho Forest Products Commission (IFPC), 2009. From Wood to Paper; http://www. idahoforests.org/forest_to_paper.htm International Agency for Research on Cancer (IARC), 1992. IARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Man: Occupational Exposures to Mists and Vapours from Strong Inorganic Acids, and Other Industrial Chemicals, vol. 54. IARC, World Health Organization, Lyon, France. International Paper Company, 2008. Global Water Use. Sustainability; http://www. internationalpaper.com/Our%20Company/Sustainability/2Performance/WaterUse. html International Union of Pure and Applied Chemistry (IUPAC), 2009. Electrostatic Precipitator. Compendium of Chemical Terminology, Internet edition. Iowa State University (ISU), 2000. Sulfuric Acid. Chemistry Material Data Safety Sheets. Department of Chemistry, ISU, November; http://avogadro.chem.iastate.edu/ MSDS/H2SO4.htm Kerns, W.D., Pavkov, K.L., Donofrio, D.J., Gralla, E.J., Swenberg, J.A., 1983. Carcinogenicity of Formaldehyde in Rats and Mice after Long-term Inhalation Exposure. Cancer Research 43, 4382–4392. Kimberly-Clark Corporation, 2008. Shaping a Healthier World: 2008 Sustainability Report; http://www.kimberly-clark.com/pdfs/2008SustainabilityReport.pdf Kociba, R.J., Keeler, P.A., Park, C.N., Gehring, P.J., 1976. 2,3,7,8-Tetrachlorodibenzop-dioxin (TCDD): Results of a 13-week Oral Toxicity Study in Rats. Toxicology and Applied Pharmacology 35, 553–574. Kovach, W., 1970. Vermont Seeks Ruling Against New York and Paper Mill on Champlain Pollution. New York Times. 6 December.

256

Handbook of Pollution Prevention and Cleaner Production

Kumar, R., Kuloor, N.R., 1970. The Formation of Bubbles and Drops. Advances in Chemical Engineering 8, 255. Lehman, M., 2009. Tomahawk Mill Cited for Violations in Fatal Explosion. WRN News, 27 January; http://www.wrn.com/gestalt/go.cfm?objectid¼18E66438-5056B82A-37FE3E93E86E3D97 Lubbers, J.R., Chauhan, S., Bianchine, J.R., 1981. Controlled Clinical Evaluations of Chlorine Dioxide, Chlorite and Chlorate in Man. Fundamental and Applied Toxicology 1, 334–338. Lubbers, J.R., Chauhan, S., Miller, J.K., et al., 1984. The Effects of Chronic Administration of Chlorine Dioxide, Chlorite and Chlorate to Normal Healthy Adult Male Volunteers. Journal of Environmental Pathology, Toxicology and Oncology 5, 229–238. Mancuso, T.F., Hueper, W.C., 1951. Occupational Cancer and Other Health Hazards in a Chromate Plant: A Medical Appraisal. I. Lung Cancers in Chromate Workers. Industrial Medicine and Surgery 20, 358–363. Marks, T.A., Worthy, W.C., Staples, R.E., 1980. Influence of Formaldehyde and Sonacide (Potentiated Acid Glutaraldehyde) on Embryo and Fetal Development in Mice. Teratology 22, 51–58. Martin, S., 2004. Paper Chase. Ecology Communications Inc. Retrieved on 21 September 2007. Maxwell, L., 1991. Size of International Paper Spill in Dispute. United Press International. 8 March. National Institute of Occupational Safety and Health (NIOSH), 1995. Registry of toxic effects of chemical substances: Chlorine dioxide. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health Division of Standards Development and Technology Transfer, Technical Information Branch. National Toxicology Program (NTP), 1989. Technical Report on the Toxicology and Carcinogenesis Studies of Pentachlorophenol (CAS No. 87-86-5) in B6C3F1 Mice (Feed Studies). NTP Tech. Report No. 349. NIH Publ. No. 89–2804. Newswire, P.R., 1993. EPA Collects $32,000 in Penalties from International Paper Company for Violations of Right-To-Know Requirements. PR Newswire. 26 April. Norton, G., 1989. IP Reports: Chloroform Emissions Soar. Valley Voice. 25 July. O’Berg, M.T., 1980. Epidemiologic Study of Workers Exposed to Acrylonitrile. Journal of Occupational Medicine 22 (4), 245–252. Occupational Safety and Health Administration (OSHA), 2009. Hydrogen Fluoride. Health Guidelines. United States Department of Labor. http://www.osha.gov/SLTC/ healthguidelines/hydrogenfluoride/recognition.html OHS Magazine, 2007. Paper Mill Settles Lockout–Tagout Fatality Case after Years of Appeals. OHS Magazine. 7 September. http://ohsonline.com/articles/2007/09/papermill-settles-lockouttagout-fatality-case-after-years-of-appeals.aspx. Paper on Web (PW), 2009. Bleaching Stages and Sequences. Chemicals Used in Pulp and Paper Manufacturing and Coating; http://www.paperonweb.com/bleach.htm Phoon, W.H., Goh, K.T., Lee, L.T., et al., 1983. Toxic Jaundice from Occupational Exposure to Chloroform. Medical Journal of Malaysia 38, 31–34 (as cited in US EPA, 1998d). Pohjanvirta, R., Wong, J., Li, W., Harper, P.A., Tuomisto, J., Okey, A.B., 1998. Point Mutation in Intron Sequence Causes Altered Carboxyl-terminal Structure in the Aryl Hydrocarbon Receptor of the Most 2,3,7,8-Tetrachlorodibenzo-p-dioxin-resistant Rat Strain. Molecular Pharmacology 54, 86–93.

Sources of air emissions from pulp and paper mills

257

President’s Commission on Environmental Quality (PCEQ), 1990. Executive Order 12737 12 December, 55 F.R. 51681. Puget Sound Business Journal, 2000. Everett Paper Mill Fined $20,000. Puget Sound Business Journal, 21 November; http://seattle.bizjournals.com/seattle/stories/2000/ 11/20/daily8.html?q¼paper%20mill%20pollution%20infractions Pulp and Paper Magazine, 1991. IP’s Environmental Troubles Stacking Up. Pulp and Paper Magazine. June. Richer, C., Decker, N., Belin, J., Imbs, J.L., Montastruc, J.L., Giudicelli, J.F., 1989. Odorous Urine in Man After Asparagus. British Journal of Clinical Pharmacology 27 (5), 640–641. Rothman, N., Li, G.L., Dosemeci, M., et al., 1996. Hematotoxicity Among Chinese Workers Heavily Exposed to Benzene. American Journal of Industrial Medicine 29, 236–246. Sandmeyer, 1989. http://www.epa.gov/chemfact/s_toluen.txt Saryan, L.A., Reedy, M., 1988. Chromium Determinations in a Case of Chromic Acid Ingestion. Journal of Analytical Toxicology 12, 162–164. Senate Subcommittee on Labor Hearing on OSHA Reform, 1992. Fulfilling the Promise of a Safe and Healthy Workplace. Federal News Service. 17 March. Shaw Environmental, 2006. Phase II Site-wide RFI Report for the BNSF Railway Company – Somerville, Texas – vol. 1. Shaw Environmental Inc. September. Singh, R.P., 1979. The Bleaching of Pulp, third ed. TAPPI Press, Atlanta. Smith, S., 2002. OSHA Fines Paper Mill $91,000. EHS Today, 18 July; http://ehstoday. com/news/ehs_imp_35659/ Smith, S., 2004. Paper Mill Fined for Hazards Related to Employee. EHS Today, 18 July; http://ehstoday.com/news/ehs_imp_37087/ Smits-van Prooije, A.E., Lammers, J.H.C.M., Waalkens-Berendsen, D.H., Kulig, B.M., Snoeij, N.J., 1993. Effects of the PCB 3,4,5,3,4,5-Hexachlorobiphenyl on the Reproduction Capacity of Wistar Rats. Chemosphere 27, 395–400. Stahl, B.U., Kettrup, A., Rozman, K., 1992. Comparative Toxicity of Four Chlorinated Dibenzo-p-dioxins (CDDs) and Their Mixture. Part I: Acute Toxicity and Toxic Equivalency Factors (TEFs). Archives of Toxicology 66, 471–477. Thienes, H., Haley, T.J., 1972. Clinical Toxicology, fifth ed. Lea & Febiger, Philadelphia, pp. 124–127. Til, H.P., Woutersen, R.A., Feron, V.J., Hollanders, V.H.M., Falke, H.E., Clary, J.J., 1989. Two-year Drinking Water Study of Formaldehyde in Rats. Food and Chemical Toxicology 27, 77–87. Tobe, M., Kaneko, T., Uchida, Y., et al., 1985. Studies of the Inhalation Toxicity of Formaldehyde. National Sanitary and Medical Laboratory Service (Japan), pp. 1–94. TRC, 1999. Baseline Risk Assessment Report for BNSF Railway’s Inactive Ponds. Somerville, Texas Final Report. Prepared for the Burlington and Santa Fe Railway Company. Fort Worth, TXTRC Environmental Corporation, September. TRC, 2000. Final RCRA Facility Investigation of BNSF Facility. Prepared for the Burlington and Santa Fe Railway Company. Fort Worth, TXTRC Environmental Corporation, January. US Department of Health and Human Services (DHHS), 1998. Toxicological Profile for Sulfur Dioxide. Agency for Toxic Substance and Disease Registry, December; http:// www.atsdr.cdc.gov/toxprofiles/tp116.pdf US Environmental Protection Agency (EPA), 1987. 0238 – Ethylene Glycol (CASRN 107-21-1). Integrated Risk Information System, September; http://www.epa.gov/ ncea/iris/subst/0238.htm

258

Handbook of Pollution Prevention and Cleaner Production

US Environmental Protection Agency (EPA), 1988. 0305 – Methanol (CASRN 67-56-1). Integrated Risk Information System, September http://www.epa.gov/ncea/iris/ subst/0305.htm US Environmental Protection Agency (EPA), 1991a. 0290 – Acetaldehyde (CASRN 7507-0). Integrated Risk Information System, October; http://www.epa.gov/ncea/iris/ subst/0290.htm US Environmental Protection Agency (EPA), 1991b. 0206 – Acrylonitrile (CASRN 10713-1). Integrated Risk Information System, November; http://www.epa.gov/ncea/ iris/subst/0206.htm US Environmental Protection Agency (EPA), 1991c. 0422 – Ammonia (CASRN 766441-7). Integrated Risk Information System, May; http://www.epa.gov/ncea/iris/ subst/0422.htm US Environmental Protection Agency (EPA), 1991d. 0419 – Formaldehyde (CASRN 5000-0). Integrated Risk Information System, January; http://www.epa.gov/ncea/iris/ subst/0419.htm US Environmental Protection Agency (EPA), 1991e. 0086 – Pentachlorophenol (CASRN 87-86-5). Integrated Risk Information System, March; http://www.epa.gov/ncea/ iris/subst/0086.htm US Environmental Protection Agency (EPA), 1994a. Final Draft for the Drinking Water Criteria Document on Trihalomethanes. Prepared for Health and Ecological Criteria Division, Office of Science and Technology. US Environmental Protection Agency (EPA), 1994b. 0405 – Chlorine (CASRN 7782-50-5). Integrated Risk Information System; http://www.epa.gov/ncea/iris/subst/0405.htm US Environmental Protection Agency (EPA), 1995a. 0396 – Hydrogen Chloride (CASRN 7647-01-0). Integrated Risk Information System, July; http://www.epa.gov/ncea/ iris/subst/0396.htm US Environmental Protection Agency (EPA), 1995b. AP-42 Section 10.2 Chemical Wood Pulping, January; http://www.epa.gov/ttn/chief/ap42/ch10/final/c10s02.pdf US Environmental Protection Agency (EPA), 1996. 0055 – Formic acid (CASRN 64-18-6). Integrated Risk Information System, February; http://www.epa.gov/ncea/iris/subst/ 0055.htm US Environmental Protection Agency (EPA), 1998a. Health Risk Assessment/Characterization of the Drinking Water Disinfection Byproduct Chloroform. Prepared for Health and Ecological Criteria Division, Office of Science and Technology, Washington, DC. Prepared by Toxicology Excellence for Risk Assessment, Cincinnati, OH, under Purchase Order No. 8W-0767-NTLX, 4 November. US Environmental Protection Agency (EPA), 1998b. 0144 – Chromium (VI) (CASRN 18540-29-9). Integrated Risk Information System, September; http://www.epa.gov/ ncea/iris/subst/0144.htm US Environmental Protection Agency (EPA), 2000. 0496 – Chlorine Dioxide (CASRN 10049-04-4). Integrated Risk Information System, October; http://www.epa.gov/ ncea/iris/subst/0496.htm US Environmental Protection Agency (EPA), 2001. 0025 – Chloroform (CASRN 67-66-3). Integrated Risk Information System; October; http://www.epa.gov/ncea/iris/subst/ 0025.htm US Environmental Protection Agency (EPA), 2002. 0088 – Phenol (CASRN 108-95-2). Integrated Risk Information System, September; http://www.epa.gov/ncea/iris/subst/ 0088.htm

Sources of air emissions from pulp and paper mills

259

US Environmental Protection Agency (EPA), 2003a. 0276 – Benzene (CASRN 71-43-2). Integrated Risk Information System, April; http://www.epa.gov/ncea/iris/subst/ 0276.htm US Environmental Protection Agency (EPA), 2003b. 0061 – Hydrogen Sulfide (CASRN 7783-06-4). Integrated Risk Information System, July; http://www.epa.gov/ncea/ iris/subst/0061.htm US Environmental Protection Agency (EPA), 2005. 0118 – Toluene (CASRN 108-88-3). Integrated Risk Information System, September; http://www.epa.gov/ncea/iris/subst/ 0118.htm US Environmental Protection Agency (EPA), 2009. Releases: Chemical Report: Paper Industry. TRI Explorer, May. Accessed 15 July; http://www.epa.gov/tri/tridata/ index.htm Van den Berg, M., Peterson, R.E., Schrenk, D., 2000. Human Risk Assessment and TEFs. Food Additives and Contaminants 17, 347–358. Vermont Public Interest and Research Group, 1998. VPIRG Uncovers IP Plans to Burn Tires. VPIRG Update. Winter. Wilson, R.H., Hough, G.H., McCormick, W.E., 1948. Medical Problems Encountered in the Manufacture of American-made Rubber. Industrial Medicine 17 (6), 199–207. Zambon, P., Ricci, P., Bovo, E., Casula, A., Gattolin, M., Fiore, A.R., Chiosi, F., Guzzinati, S., 2007. Sarcoma Risk and Dioxin Emissions from Incinerators and Industrial Plants: A Population-based Case–Control Study (Italy). Environmental. Health 6 (19), 1–19. Zhang, J., Li, X., 1987. Chromium Pollution of Soil and Water in Jinzhou. Journal of Chinese Preventive Medicine 21, 262–264.

7 Pollution prevention and best practices for the pulp and paper industry 7.1 Introduction This final chapter provides general guidance on pollution prevention (P2) and cleaner production. Many of the general concepts on P2 and the ISO 14000 environmental management system discussed in Chapter 5 are equally applicable. The reader can refer back to Section 5.4 in particular for discussions. In terms of cleaner production, we return again to gasification as a technology that affords pulp and paper mills an important infrastructure investment into green power and overall reduction in the environmental footprint for the industry. Gasification technologies are now at the stage where they may be implemented at mills for black liquor gasification. Integrated plants capable of producing biofuels are perhaps only a few years away from commercialization, but interim investments into the basic building blocks are currently available. Investments into this technology for fully integrated facilities capable of producing electricity and biofuels can be in the range of $200–400 million. There are a number of cost and technical feasibility assessments that the Europeans in particular have focused on. While these investment levels appear high, the returns are attractive. Large-scale adoption of black liquor gasification technology in an integrated gasification combined-cycle (IGCC) configuration would allow production of more than 20,000 MW of green electricity in the USA alone. Alternatively, using the synthesis gas produced from black liquor gasification as feedstock for production of biodiesel would result in the equivalent of more than 280 million barrels of oil per year, which would displace approximately 7% of US oil imports with a domestically produced, renewable fuel. The last section of this chapter provides an audit form that can help guide environmental managers through an initial environmental review (IER). As noted in Chapter 5, the IER is a means by which the environmental aspects of the facility can be logically identified and corrective actions aimed at improving environmental performance can be prioritized.

7.2 General P2 practices In Chapter 8 of the Handbook of Pollution Prevention Practices, Cheremisinoff (2001) provides case studies and examples of successful P2 practices in this Handbook of Pollution Prevention and Cleaner Production Vol. 2 Copyright Ó 2010 by Elsevier Inc. All rights reserved.

262

Handbook of Pollution Prevention and Cleaner Production

industry sector. A summary of some of these efforts is provided below. The majority of these practices have been aimed at solid waste and wastewater reductions. The reader should note that pulp and paper are manufactured from raw materials containing cellulose fibers, generally wood, recycled paper, and agricultural residues. The main steps in pulp and paper manufacturing are: raw material preparation, such as wood debarking and chip making; pulp manufacturing; pulp bleaching; paper manufacturing; and fiber recycling. Pulp mills and paper mills may exist separately or as integrated operations. Manufactured pulp is used as a source of cellulose for fiber manufacture and for conversion into paper or cardboard. Pulp manufacturing starts with raw material preparation; this includes debarking (when wood is used as raw material), chipping, and other processes such as depithing (for example, when bagasse is used as the raw material). Cellulosic pulp is manufactured from the raw materials, using chemical and mechanical means. The manufacture of pulp for paper and cardboard employs mechanical and thermomechanical, chemimechanical, and chemical technologies. Mechanical pulping separates fibers by various techniques, which include disk abrasion and billeting. Chemimechanical processes involve mechanical abrasion and the use of chemicals. Thermomechanical pulps used for making newsprint and similar products are manufactured from raw materials by the application of heat or steam, in addition to mechanical operations. Chemimechanical pulping and chemithermomechanical pulping (CTMP) are similar methods but use less mechanical energy; these methods soften the pulp with sodium sulfite, carbonate, or hydroxide. Chemical pulps are manufactured by the method of cooking known as digesting. The raw materials are digested using the kraft (sulfate) and sulfite processes. Kraft processes produce a variety of pulps used mainly for packaging and high-strength papers and board. In this method, wood chips are cooked with caustic soda to produce brownstock, which is then washed with water to remove the cooking liquor for the recovery of chemicals and energy. This recovered cooking liquor is referred to as ‘‘black liquor’’ and in the past was sometimes called ‘‘black gold’’ because of its value for energy recovery. Note that pulp is also manufactured from recycled paper. Mechanical pulp can be used without bleaching to make printing papers for applications in which low brightness is acceptable – primarily, newsprint. For most printing, for copying, and for some packaging grades, the pulp has to be bleached. For mechanical pulps, most of the original lignin in the raw pulp is retained but is bleached with peroxides and hydrosulfites. In the case of chemical pulps (kraft and sulfite), the objective of bleaching is to remove the small fraction of lignin remaining after the digestion process. Oxygen, hydrogen peroxide, ozone, peracetic acid, sodium hypochlorite, chlorine dioxide, chlorine, and other chemicals are used to transform lignin into an alkali-soluble form. An alkali, such as sodium hydroxide, is necessary in the bleaching process to extract the alkali-soluble form of lignin.

Pollution prevention and best practices for the pulp and paper industry

263

In the bleaching process the pulp is washed with water. Oxygen is most often used in the first stage of bleaching. The trend is to avoid the use of any kind of chlorine chemicals and employ ‘‘totally chlorine-free’’ (TCF) bleaching. TCF processes allow the bleaching effluents to be fed to the recovery boiler for steam generation; the steam is then used to generate electricity. Elemental chlorine-free (ECF) processes use chlorine dioxide to bleach certain grades of pulp. The use of elemental chlorine for bleaching is not recommended. Only ECF processes are acceptable and, from an environmental perspective, TCF processes are preferred. The soluble organic substances removed from the pulp in bleaching stages that use chlorine or chlorine compounds, as well as the substances removed in the subsequent alkaline stages, are chlorinated. The chlorinated organic substances are toxic and include dioxins, chlorinated phenols, and other chemicals. It is not practical to recover chlorinated organics in effluents, since the chloride content causes excessive corrosion. Finished pulp is dried for shipment or may be used to manufacture paper on site (in an ‘‘integrated’’ mill). Paper and cardboard are made from pulp by deposition of fibers and fillers from a fluid suspension on to a moving forming device that also removes water from the pulp. The water remaining in the wet web is removed by pressing and then by drying, on a series of hollow-heated cylinders (for example, calender rolls). Chemical additives are added to impart specific properties to paper, and pigments may be added for color. The negative environmental impacts of the process result from the pulping and bleaching processes. In some processes, sulfur compounds and nitrogen oxides are emitted to the air, and chlorinated and organic compounds, nutrients, and metals are discharged to the wastewaters. As noted in the previous chapter, in the kraft pulping process, highly malodorous emissions of reduced sulfur compounds, measured as total reduced sulfur (TRS) and including hydrogen sulfide, methyl mercaptan, dimethyl sulfide, and dimethyl disulfide, are emitted, typically at a rate of 0.3–3 kilograms per metric ton (kg/t) of air-dried pulp (ADP; note that ADP is defined by convention as 90% bone-dry fiber and 10% water). The World Bank Organization (WBO, 1998) reports the following emissions as typical:    

particulate matter, 75–150 kg/t; sulfur oxides, 0.5–30 kg/t; nitrogen oxides, 1–3 kg/t; volatile organic compounds (VOCs), 15 kg/t from black liquor oxidation.

In the sulfite pulping process, sulfur oxides are emitted at rates ranging from 15 to over 30 kg/t. Other pulping processes, such as mechanical and thermomechanical methods, generate significantly lower quantities of air emissions. Steam- and electricity-generating units using coal or fuel oil emit fly ash, sulfur oxides, and nitrogen oxides. Coal burning can emit fly ash at the rate of 100 kg/t of ADP. The WBO also notes that wastewaters are discharged at a rate of 20–250 cubic meters per metric ton (m3/t) of ADP. Wastewaters are high in: biochemical

264

Handbook of Pollution Prevention and Cleaner Production

oxygen demand (BOD), at 10–40 kg/t of ADP; total suspended solids, 10–50 kg/t of ADP; chemical oxygen demand (COD), 20–200 kg/t of ADP; and chlorinated organic compounds, which may include dioxins, furans, and other adsorbable organic halides (AOX), at 0–4 kg/t of ADP. Wastewater from chemical pulping contains 12–20 kg of BOD/t of ADP, with values of up to 350 kg/t. For mechanical pulping, wastewater discharges are 15–25 kg BOD/t of ADP. For chemimechanical pulping, BOD discharges are three to 10 times higher than those for mechanical pulping. Phosphorus and nitrogen are also released into wastewaters. The main source of nutrients, nitrogen, and phosphorus compounds is raw material such as wood. The use of peroxide, ozone, and other chemicals in bleaching makes it necessary to use a complexing agent for heavy metals such as manganese. One of the greatest sources of solid wastes is wastewater treatment sludge (50–150 kg/t of ADP). Solid materials that can be reused include waste paper, which can be recycled, and bark, which can be used as fuel, whereas lime sludge and ash is typically disposed of in an appropriate landfill. The discharge of chlorine-based organic compounds (from bleaching) and of other toxic organics is of great concern from pulp and paper mills. The unchlorinated material is mostly black liquor that has escaped the mill recovery process. Some mills have been reporting 100% recovery, which is a major accomplishment compared to a decade earlier. Industry developments demonstrate that totally chlorine-free bleaching is feasible for many pulp and paper products but may not be able to produce certain grades of paper. There are a variety of P2 programs that the industry has focused on for reducing wastewater discharges and in some instances in minimizing air emissions. Some of the general areas where there has been limited success include:     

 



Use of energy-efficient pulping processes. Lowering esthetic specifications by accepting less bright products. For less bright products such as newsprint, thermomechanical processes and recycled fiber may have been used. The generation of effluents has been reduced through process modifications and recycle of wastewaters. Reduced effluent volume and treatment requirements have been achieved by using dry instead of wet debarking methods, through recovering pulping chemicals by concentrating black liquor and burning the concentrate in a recovery furnace. Recovering cooking chemicals by recausticizing the smelt from the recovery furnace and using high-efficiency washing and bleaching equipment. Minimize unplanned or nonroutine discharges of wastewater and black liquor, caused by equipment failures, human error, and faulty maintenance procedures, by training operators, establishing good operating practices, and providing sumps and other facilities to recover liquor losses from the process. Reducing bleaching requirements by process design and operation. The following measures have reduced emissions of chlorinated compounds to the environment: before bleaching, reducing the lignin content in the pulp (Kappa number of 10) for hardwood by extended cooking and by oxygen delignification under elevated

Pollution prevention and best practices for the pulp and paper industry

 

265

pressure; optimizing pulp washing prior to bleaching; using TCF or, at a minimum, ECF bleaching systems; using oxygen, ozone, peroxides (hydrogen peroxide), peracetic acid, or enzymes (cellulose-free xylanase) as substitutes for chlorine-based bleaching chemicals; recovering and incinerating maximum material removed from pulp bleaching; where chlorine bleaching is used, reducing the chlorine charge on the lignin by controlling pH and by splitting the addition of chlorine. Minimization of sulfur emissions to the atmosphere has been achieved by using a low-odor design black liquor recovery furnace. Using energy-efficient processes for black liquor chemical recovery, preferably aiming for a high solid content (say, 70%) has also proven effective in reducing emissions and achieving greater energy efficiency.

7.3 Cleaner production In the process of making paper the black liquor is first concentrated, and subsequently incinerated in recovery boilers, recovering the chemicals and generating steam for the plant (used to produce electricity in a steam turbine plant), with an estimated overall efficiency of 23% (Nilsson et al., 1995). While this co-generation technology is economical and well matched to the production demands for heat and electricity, recovery boilers are the largest point source of emissions at pulp and paper mills. High investments of recovery boilers, required pollution controls, and increasing electricity demand (and decreasing steam use) are incentives to invest in other co-generation options. Options are fluidized-bed combustion or gasification with gas turbine-based co-generation. Gasification produces a fuel gas with heating values of 3–4 MJ/Nm3 Higher Heating Value (HHV) using air or 89 MJ/Nm3 (HHV) using oxygen as gasifying medium (Grace and Timmer, 1995; Rezaiyan and Cheremisinoff, 2005). The gas must first be scrubbed to recover inorganic chemicals (e.g. alkalines, H2S) in order to prevent damage to the gas turbine and reduce emissions. The gas may be burned in a gas turbine or in steam boilers. Besides black liquor, a gasifier can also use wood wastes (bark and other residues) to produce fuel gas. Typically, this is around 5–10% of the pulp wood and would add 4 GJ per tonne of pulp to the 20–25 GJ/tonne pulp from the black liquor. Gasification can be classified as low-temperature (indirect) and high-temperature processes. A problem of low-temperature gasification is maintaining the right temperature to reduce tar formation and to avoid agglomeration of bed material. The low-temperature processes use a fluidized bed. Solid sodium carbonate is used as the bed material and is precipitated out (and reused). High-temperature processes use an entrained bed gasifier, from which the chemicals are recovered in the smelt (comparable to recovery boilers). The high temperatures lead to higher carbon conversion rates, but may lead to more corrosion. The synthesis gas from gasifiers could be converted into liquid fuels using catalytic synthesis technologies that are already commercially established today in the gas-to-liquids or coal-to-liquids industries. Biorefinery designs are reported for a reference mill in the southeastern USA, together with the associated

266

Handbook of Pollution Prevention and Cleaner Production

mass/energy balances, air emissions estimates, and capital investment requirements (TAPPI Journal, 2009). Biorefineries provide chemical recovery services and co-produce process steam for the mill, some electricity, and one of three liquid fuels: a Fischer–Tropsch synthetic crude oil (which could be refined to vehicle fuels at an existing petroleum refinery), dimethyl ether (a diesel engine fuel or propane substitute), or an ethanol-rich mixed-alcohol product. Compared with installing new Tomlinson power/recovery systems, biorefineries would require more capital investment and greater purchases of woody residues for energy use. However, because biorefineries would be more efficient, have lower air emissions, and produce a more diverse product slate, the internal rate of return (IRR) on the incremental capital investment is reported to lie between 14% and 18%, assuming a $50/barrel world oil price. The IRRs would more than double if federal and state financial incentives were captured and oil continues to approach and exceed $90/barrel. Industry-wide adoption of such biorefining in the USA would provide significant energy and environmental benefits. With fluidized-bed gasification, low-cost and potentially CO2-neutral solid fuels can be converted into combustible gas. This replaces expensive oil, natural gas, or coal. Low-grade fuels such as wood chips, wood waste, bark, demolition wood, straw and wastes such as in-origin classified recycled fuel (REF) and refuse-derived fuel (RDF) have been successfully gasified. A circulating fluid bed (CFB) gasifier is a multifuel system that tends to have robust operating ranges such that a mixture of different fuels can be used in the same unit. Looking to Europe as an example, about 30–150 MWth of biofuel energy is available within a 50 km radius of a power plant. For instance, by connecting a gasifier to a medium- or large-sized coal-fired boiler with a high efficiency steam cycle, local biomass sources can be converted to CO2-neutral power and heat at high efficiency, compared with stand-alone boilers with the same fuel input. A stand-alone power plant can also be based on the clean-gas gasification technology. In such a concept, clean gas is fired alone in a new gas-fired boiler, which can be designed for higher steam data than normal boilers utilizing wastebased fuels, resulting in high efficiency in electricity production. While we do not endorse any one design, developer or supplier, we note several systems that are now in a state of commercial readiness. Foster Wheeler, as one example (Palonen et al., 2005), has developed an atmospheric CFB gasification system that consists of a gasification reactor, a cyclone to separate the circulating-bed material from the gas, and a return pipe to return the circulating material to the bottom part of the gasifier. The components listed are refractory lined. From the cyclone, the hot product gas flows into an air preheater located below the cyclone. Gasification air is blown with a highpressure air fan through an air distribution grid at the bottom of the reactor, below a bed of particles. The air fluidizes the bed particles and conveys some of them out of the reactor and into the cyclone, where most of the solids are separated from the gas and returned to the lower portion of the gasifier. Both the gas and solids are extracted from the bottom of the cyclone.

Pollution prevention and best practices for the pulp and paper industry

267

The circulating solids contain char that is combusted with the fluidizing air, generating the heat required for the pyrolysis process and subsequent gasification reactions, which are endothermic. The circulating material also serves as a heat carrier and stabilizes the process temperatures. Coarse ash accumulates in the gasifier and is removed from the bottom with a water-cooled screw. Figure 7.1 illustrates the main components of the system. Foster Wheeler has had good commercial success with its CFB gasifier. The first system connected to a PC boiler was constructed in 1997 at the Kymija¨rvi power plant of Lahden La¨mpo¨voima Oy. The Kymija¨rvi power plant produces electric power (167 MWe) and district heat (240 MW) for the city of Lahti, Finland. The Lahti gasifier was connected to a 20-year-old Benson-type oncethrough boiler, the steam data of which are 125 kg/s, 540 C/170 bar/540 C/40 bar. The boiler was converted from heavy-oil firing to coal firing in 1982, and typically it operates at about 7000 hours annually, depending on the heat demand and electricity prices. The Lahti gasifier started commercial operation in 1998 and initially used biofuels such as bark, wood chips, sawdust, and

Figure 7.1 Simplified diagram of the Foster Wheeler CFB gasifier.

268

Handbook of Pollution Prevention and Cleaner Production

uncontaminated wood waste. Other fuels have also been tested subsequently, including in-origin classified waste fuel (REF), railway sleepers, and shredded tires. As a result of availability and price changes, the share of REF fuel has gradually increased at the expense of cleaner biofuels. Foster Wheeler has reported that the gasifier has operated well with varying fuel mixes, with availabilities of 96% or higher. Equally impressive is that the installed system had a significantly smaller environmental footprint. The following are reported reductions in stack emissions:        

CO2 – decrease by ~100,000 tons annually; NOx – decrease by 10 mg/MJ (5–10%); SOx – decrease by 20–25 mg/MJ; HCl – increase by 5 mg/MJ; CO – no change; particulates – decrease by 15 mg/m3; heavy metals – slight increase in some elements, base level low; dioxins, furans, PAHs, benzenes, and phenols – no change.

Following the success in Lahti, a gasification plant based on the same concept was constructed at the Electrabel Ruien power plant, which is the largest fossil fuel-fired power plant in Belgium. The gasifier was connected to the tangentially fired once-through boiler (steam values 180 bar/540 C) of Unit 5, which has a power output of 190 MWe. The new plant increases the use of renewable energy, thus reducing CO2 emissions. The Flemish legislation includes a system of green certificates to encourage the use of renewable energy. The fuel for the gasifier is fresh wood chips, but the gasifier can also utilize other types of fuel, such as bark, hard and soft board residues and dry, recycled wood chips, and the fuel moisture may vary between 20% and 60%. Depending on the fuel mix, the heat input to the boiler is normally 45–70 MW. The plant has been in commercial operation since 2003. ThermoChem Recovery International (http://www.forestencyclopedia.net/ fen_frame?link¼http://www.tri-inc.net/) has commercialized a low-temperature process, where black liquor is indirectly heated to produce a hydrogen-rich gas. This process also produces a dry solid inorganic smelt that reduces the potential for smelt-water explosion hazards. ThermoChem has two commercial plants installed: Trenton, Ontario and one in partnership with Georgia Pacific in Big Island, Virginia. A Swedish company, Chemrec AB (http://www.forestencyclopedia.net/fen_ frame?link¼http://www.chemrec.se/), uses a high-temperature gasification system. This system can work in parallel with existing Tomlinson recovery boilers or serve as a replacement for old boilers. This replacement system has the capacity to double the biobased electricity produced and increase pulping capacity by 5%. Chemrec systems have been used across Sweden as well as in partnership with the Weyerhaeuser mill in New Bern, North Carolina. The raw gases produced by the system can be converted to biobased syngas, which can be used on site or sold to the market. The soilds that are produced in the black

Pollution prevention and best practices for the pulp and paper industry

269

liquor can be problematic, particularly if the pulping chemicals were high in sulfur and sodium content. Gasification of black liquor has shown significant improvements over Tomlinson boilers with regard to SOx and NOx emissions and TRS levels, thus improving future pulp yields. Detailed studies have also demonstrated that, when combined with a gas turbine, black liquor gasification can produce enough energy to make the pulping industry a net exporter of energy. The Chemrec AB process is illustrated in Figure 7.2. Chemrec AB’s approach is not unlike other developers’. Their concept includes a conventional biomass boiler to make up the energy deficit that otherwise would result from the export of energy-rich biofuel from the pulp mill. This means that a feedstock swap is made – the ideal gasification feedstock black liquor is withdrawn from the pulp mill and replaced by any kind of low-grade biomass. The boiler fuel could be forestry or industrial wood waste, agricultural waste such as corn stover or wheat straw, purpose-grown biomass such as switchgrass or willow, or even the organic fraction of municipal waste. When using purpose-grown biomass, the only quality requirement is that the biomass burns well in a boiler. This means that the selection of what to grow can be based solely on productivity, production cost, and the environmental impact of the Black liquor Atomizing medium

Cooling water Boiler feed water*

Gasification

Oxygen REACTOR Separation of gas and smelt

Raw gas

GAS COOLER

QUENCH Particulate removal and gas cooling Green liquor Condensate Weak wash

Figure 7.2 Schematic of Chemrec AB process. Source: http://www.biomassmagazine.com/article.jsp?article_id¼2818

270

Handbook of Pollution Prevention and Cleaner Production

cultivation. Also, all parts and constituents of the biomass can be used. The result is very high land-use efficiency both in terms of amount of fuel possible to produce per acre and year and in terms of being able to use marginal land and low-input production methods, all important for sustainable biofuels production. These are also aspects that are important when we consider GHG (Greenhouse Gas) release from indirect land-use change. Gasification processes have high-energy feedstock flexibility and are capable of producing a range of green fuels, including dimethyl ether (DME), methanol, ethanol, synthetic diesel, synthetic gasoline, and biogas. Additionally, biofuels from a black liquor gasification process have an advantage in terms of well-to-wheel carbon dioxide emission reduction and energy efficiency. European studies performed by various research institutes of the auto and refinery industries and the Joint Research Centre of the European Commission examined different feedstocks, conversion processes, and fuel products. Synthetic diesel and DME from forest harvest residues over the black liquor gasification route both showed among the highest well-to-wheel greenhouse gas reduction and energy efficiency. In comparison with conventional combustion technology (Tomlinson boilers), pressurized black liquor gasification can increase the energy recovery in the pulping process from 65% using the most modern combustion equipment to about 75%. Compared with much of the existing installed equipment, of which the majority is 30 years of age or older, electric energy generation can increase by a factor of 2–3. The quality of green liquor from a gasifier can provide process advantages, since sodium and sulfur are recovered separately for recycling to the digester, offering the opportunity for increased pulp yield and quality. The causticizing load does increase, however, which is a disadvantage. In addition, the risk of a smelt-water explosion involved in conventional boiler technology is absent when gasifying black liquor, due to the small smelt inventory in the process. A good starting reference for the reader to obtain an overview of the technology is the Proceedings of the European Conference on Biorefinery Research in Helsinki (Laadalv, 2006), in which Chemrec presented a detailed presentation on its concept for a modern pulp mill with an integrated gasification system producing biofuels. There is no question that black liquor gasification is a promising alternative for recovery of energy and chemicals from spent pulping liquor. A key point is that because the organic fraction of black liquor comes from biomass, it is a carbon-neutral fuel and is therefore classified as a renewable energy resource. Large-scale adoption of black liquor gasification technology in an integrated gasification combined-cycle (IGCC) configuration would allow production of more than 20,000 MW of green electricity in the USA alone according to the Institute for Combustion and Energy Studies (http://www.eng.utah.edu/~whitty/ utah_blg/). Using the synthesis gas produced from black liquor gasification as feedstock for production of automotive fuels (e.g. biodiesel) would result in the equivalent of more than 280 million barrels of oil per year. This impressive figure represents replacing more than 7% of US oil imports with a domestically produced, renewable fuel.

Pollution prevention and best practices for the pulp and paper industry

271

7.4 Audit forms for initial environmental reviews The reader may refer back to Section 5.4 in Chapter 5 for a discussion of environmental management systems and the concept of conducting environmental reviews, or what we prefer to call initial environmental reviews (IERs). Regardless of how well a facility may be perceived to meet compliance obligations, conducting an IER and establishing regular inspections using audit forms aided by an environmental management information system (EMIS) will allow the facility to continually improve its environmental performance and further identify cost reduction opportunities. The authors discovered a reasonably detailed checklist for pulp and paper mills developed by the China–Canada Cooperation Project in Cleaner Production (http://www. chinacp.org.cn/eng/cpprojects/canada/cccpcp_index.html), which we recommend be used as a starting basis for the IER. We have modified the checklist and updated some sections for clarity. In performing the audit, it is advisable to depend on process flow sheets so that the facility can be logically reviewed in a systematic manner.

General information Name of the facility: Telephone Fax Email Web page (if applicable)

: : : :

Name of the general manager Telephone Fax Email

: : : :

Contact persons responsible for completing the checklist: Name and title Telephone Fax Email

: : : :

272

Handbook of Pollution Prevention and Cleaner Production

Facility operations What type and quantity of finished products are produced at the mill? Product

Quantity (tons/year) 1999

1998

Is the mill operating 7 days a week, 24 hours per day?

If not, indicate the operating schedule:

Indicate the turnaround (shut down) periods (if any):

How many employees are presently working at the mill?

What is the annual production of the mill for the following years? 2008 Production (tons/year)

What is the main source of energy?

What is the main source of fresh water?

What quantity of fresh water is used per day, per year? Per day: Per year:

2009

2010

Pollution prevention and best practices for the pulp and paper industry

List all water meters present in the mill (starting at the water intake and moving downstream through the process) and indicate their location: Water meter 1 2 3 4 5 6 7 8 9 10 (Continue on a separate page if necessary)

Location

Does the fresh water have to be treated before entering the paper-making process?

If the answer is yes, what type of treatment is applied?

List all pollution control devices: Atmospheric emission control device

Location

Is there a general flow sheet showing each section of the mill in detail? Attach to report.

Is there a mill plot plan showing all major departments/equipment? Attach to report.

273

274

Handbook of Pollution Prevention and Cleaner Production

Prepare a list of the major equipment present at the mill: Type of equipment

Year of installation

Type of equipment

Paper machine 1 Paper machine 2 Paper machine 3 Paper machine 4 Paper machine 5 Paper machine 6 Paper machine 7 Paper machine 8 Paper machine 9 Paper machine 10 Digester pulp line 1 Digester pulp line 2 Ble aching plant 1 Bleaching plant 2 Washing line 1 Washing line 2 Washing line 3 Washing line 4 Evaporator 1 Evaporat or 2 Recovery boiler Causticizing system Lime kiln Boiler 1 Boiler 2 Boiler 3 Boiler 4 Boiler 5 Turbo generator 1 Turbo generator 2 Turbo generator 3 Wastewater treatment plant Is the mill purchasing power from the grid or is it producing its own?

How much power is generated on site?

Year of installation

Pollution prevention and best practices for the pulp and paper industry

What type of generator is used?

What is the amount of steam required to produce the needed power?

Is the mill selling excess electricity to the grid?

Is the steam required in the process bought or is it produced on site?

What types of fuels are used (coal, oil, gas, biomass)? Type of fuel

If coal is used, give the following information: Sulfur content (%) Ash content (%) Calorific value

If oil is used, give its calorific value:

Is there a scrubber on the gas after burning?

What is the type of furnace used?

Quantity

275

276

Handbook of Pollution Prevention and Cleaner Production

What is the amount of fresh water required for steam generation?

Is steam condensate recovered? If yes, in which quantity? What is the amount of steam produced by the boilers? Are steam meters available for each department using steam? Raw materials Provide the following information concerning raw materials used: Type of raw material

Quantity used per year (tons/year)

Quantity used per day (tons/year)

Moisture content (%)

Silica content (%)

Does the moisture content of the raw materials remain constant all year around?

Where are the raw materials stored?

What is the typical storage period (number of days)?

Is the raw material screened before being used in the process?

Is fresh water used in the raw material screening and washing process?

If yes, what is the amount?

Pollution prevention and best practices for the pulp and paper industry

Raw material cooking – pulp manufacturing What are the chemicals used to cook the raw materials and what is their quantity? Chemical product

Quantity (tons)

Is anthraquinone used in the cooking process?

Provide the details of the recipe per digester and indicate the size of each digester:

Is the flow of the cooking liquor entering the digester monitored?

If yes, at which frequency?

Are the temperature and pressure inside the digester monitored?

If yes, what are their maximum values?

How long does it take to complete the cooking process for one digester?

277

278

Handbook of Pollution Prevention and Cleaner Production

What is the yield of the cooking process?

Is the cooked pulp blown or is it emptied on the floor?

If the pulp is blown, is there a heat recovery system coming after this step?

Are the flow and temperature of the pulp coming out of the digester monitored?

If yes, at which frequency?

Is the black liquor recycled in the cooking process?

Pulp washing, screening, and cleaning How many pulp washers are there at the mill?

What is the tonnage of pulp washed?

What is the quantity of fresh water used for pulp washing?

What is the consistency of the pulp entering the first washer?

What is the consistency of the pulp leaving the last washer?

Pollution prevention and best practices for the pulp and paper industry

279

What is the yield of the process after washing?

What is the Baume (% solids) of the washed pulp filtrate?

Following the pulp washers, how many screens are there?

What is the quantity of fresh water used for pulp screening?

What is the yield of the process after screening?

Are the flow rate and the pH of the black liquor monitored?

If yes, what are their average values? Flow rate =

pH =

What is the fiber content of the weak black liquor after the washing operation?

What is the Baume (% solids) of the black liquor after the washing operation?

How much of the production is rejected during this process and where?

Is there any additive used in this department such as defoamer, talc, or any pitch control agent?

280

Handbook of Pollution Prevention and Cleaner Production

Black liquor evaporation Is the black liquor recovered? If the black liquor is recovered, what is the recovery rate and how is it calculated?

How is it recovered (collected and sold, collected and reused, sent to the sewer or sent to an evaporator)?

Assuming the black liquor is evaporated, is there a multiple effect evaporator in operation at the mill?

What is the average flow of the weak black liquor to be evaporated?

What is the weak black liquor silica content?

What is the Baume (% solids) of the weak black liquor to be evaporated?

What is the Baume (% solids) of the strong black liquor after evaporation?

At which frequency does the evaporator have to be water washed?

What quantity of steam is used per ton of evaporated water?

Pollution prevention and best practices for the pulp and paper industry

281

Recovery boiler What is the type of recovery boiler in operation (cascade, low odor, other)?

What is the capacity of the recovery boiler in tons of solids burnt?

What is the normal flow of strong black liquor going to the recovery boiler?

Which product is used to light the recovery boiler (oil, propane, natural gas, other)?

Is there a scrubber or a precipitator that intercepts the gas coming out of the recovery boiler?

What is used to dissolve the smelt in the dissolving tank (weak cooking liquor or fresh water)?

What is the concentration of the green liquor in the dissolving tank?

282

Handbook of Pollution Prevention and Cleaner Production

Causticizing Are dregs removed from the green liquor?

If yes, how are they removed?

What is the temperature of the green liquor before adding lime?

What is the average flow of the green liquor going to the slaker?

What is the temperature in the last causticizing tank?

What is the retention time in the causticizers?

How is the lime mud separated from the cooking liquor, by filtration or by sedimentation?

Is the lime mud sent to a lime kiln to be converted to quicklime?

If not, where is the lime mud disposed of ?

Pollution prevention and best practices for the pulp and paper industry

283

Lime kiln Assuming lime mud is sent to a lime kiln

What is the average flow of lime mud going to the mud washer?

What is the average consistency of the lime mud going to the mud washer?

Is gas or oil used to heat the kiln?

What is the temperature in the calcining zone of the kiln?

What is the temperature of the gas leaving the kiln?

Is there a scrubber or a precipitator intercepting the gas coming from the kiln?

How much lime is produced per day?

Is the mill using lime rock or quicklime as raw material and what is the amount?

Bleaching agents Does the mill purchase any bleaching agents? If yes, indicate which ones, their quantity, and how they are delivered to the mill (by train or by truck): Bleaching agents purchased by the mill Chlorine Caustic soda Sodium hypochlorite Calcium hypochlorite

Quantity purchased (tons)

Delivery mode (train or truck)

284

Handbook of Pollution Prevention and Cleaner Production

Does the mill produce (on-site) any bleaching agents?

If yes, indicate which ones and the produced quantities. Bleaching agent

Quantity produced (tons)

Indicate the concentrations of the following bleaching agents: Bleaching agents Caustic soda Sodium hypochlorite Calcium hypochlorite

Concentration (mg/l)

Is the residue resulting from the preparation of hypochlorite landfilled or it is reused in the process?

If the residue is reused explain how and where:

Fill in the following table concerning bleaching agents storage: Bleaching agents

Storage type (tank, reservoir, other)

Pulp bleaching How many bleaching stages are there?

Capacity (l)

Pollution prevention and best practices for the pulp and paper industry

285

What are the chemicals used in the bleaching process (chlorine, chlorine dioxide, hydrogen peroxide, oxygen, ozone, etc.)?

Describe the bleaching sequence for each bleaching stage.

For each bleaching stage, provide the following information: Parameter Temperature (°C) Amount of chemicals used per ton of bleached pulp (kg/t) Typical retention time (minutes) Consistency (%) Chemical residual after each stage

Stage 1

Stage 2

Stage 3

What is the yield of the process after each bleaching stage? Yield (%) Stage 1 Stage 2 Stage 3 Stage 4 How are the chemicals controlled (automatically or by manual valves)?

Where is fresh water used in this process?

What is the quantity of fresh water used per ton of bleached pulp at each stage? Quantity of fresh water (liters) Stage 1 Stage 2 Stage 3 Stage 4

Stage 4

286

Handbook of Pollution Prevention and Cleaner Production

Paper-making process (refiners and paper machines) How many paper machines are there? Give the following information concerning each paper machine (PM): PM-1

PM-2

PM-3

PM-4

PM-5

PM-6

PM-7

PM-8

PM-9

PM-10

Are refiners used on the approach system of the paper machines? How many refiners are there? What is the freeness or SR degrees after refining? Width (m) Max. speed (m/min) Type of product Temperature in the wire pit (°C) Fourdrinier (F) or cylinder (C) in the forming section? Number of presses Is the sheet dried with heated cylinders? What is the steam pressure in the cylinders? Quantity of fresh water used per ton of paper produced (liters) Is there any control system on the paper machine for basis weight, humidity, etc.? What quantity of the excess water is recovered (liters)? How many days per month is the paper machine in operation?

At the end of the refining process, is the pulp centrifuged in order to remove any remaining impurities? If yes, are the residues directed to a disposal site? Give the loading pressures for each press of each paper machine: Press #1 Loading pressure PM-1 Loading pressure PM-2 Loading pressure PM-3 Loading pressure PM-4 Loading pressure PM-5 Loading pressure PM-6 Loading pressure PM-7 Loading pressure PM-8 Loading pressure PM-9 Loading pressure PM-10

Press #2

Press #3

Press #4

Pollution prevention and best practices for the pulp and paper industry

287

What is the pulp furnish for each paper machine: Raw material PM-1 Softwood Hardwood Reed Straw Recycled pulp De-inked pulp Raw material PM-3 Softwood Hardwood Reed Straw Recycled pulp De-inked pulp Raw material PM-5 Softwood Hardwood Reed Straw Recycled pulp De-inked pulp Raw material PM-7 Softwood Hardwood Reed Straw Recycled pulp De-inked pulp Raw material PM-9 Softwood Hardwood Reed Straw Recycled pulp De-inked pulp

Amount of pulp used (%)

Type of filler used

Amount of filler used

Amount of pulp used (%)

Type of filler used

Amount of filler used

Amount of pulp used (%)

Type of filler used

Amount of filler used

Amount of pulp used (%)

Type of filler used

Amount of filler used

Amount of pulp used (%)

Type of filler used

Amount of filler used

Raw material PM-2 Softwood Hardwood Reed Straw Recycled pulp De-inked pulp Raw material PM-4 Softwood Hardwood Reed Straw Recycled pulp De-inked pulp Raw material PM-6 Softwood Hardwood Reed Straw Recycled pulp De-inked pulp Raw material PM-8 Softwood Hardwood Reed Straw Recycled pulp De-inked pulp Raw material PM-10 Softwood Hardwood Reed Straw Recycled pulp De-inked pulp

Amount of pulp used (%)

Type of filler used

Amount of filler used

Amount of pulp used (%)

Type of filler used

Amount of filler used

Amount of pulp used (%)

Type of filler used

Amount of filler used

Amount of pulp used (%)

Type of filler used

Amount of filler used

Amount of pulp used (%)

Type of filler used

Amount of filler used

List the chemicals, such as pH adjuster, wet strength agents, starch, and sizing agents, that are added to the pulp.

288

Handbook of Pollution Prevention and Cleaner Production

What is the consistency of the pulp at the following sections of each paper machine? PM-1

Pulp consistency

Head box Couch press After press #1 After press #2 After press #3, if any After press #4, if any After dryer PM-4 Head box Couch press After press #1 After press #2 After press #3, if any After press #4, if any After dryer PM-7 Head box Couch press After press #1 After press #2 After press #3, if any After press #4, if any After dryer PM-10

Pulp consistency

Pulp consistency

PM-2

Pulp consistency

Head box Couch press After press #1 After press #2 After press #3, if any After press #4, if any After dryer PM-5 Head box Couch press After press #1 After press #2 After press #3, if any After press #4, if any After dryer PM-8

Pulp consistency

Pulp consistency

Head box Couch press After press #1 After press #2 After press #3, if any After press #4, if any After dryer

PM-3 Head box Couch press After press #1 After press #2 After press #3, if any After press #4, if any After dryer PM-6 Head box Couch press After press #1 After press #2 After press #3, if any After press #4, if any After dryer PM-9

Pulp consistency

Pulp consistency

Pulp consistency

Head box Couch press After press #1 After press #2 After press #3, if any After press #4, if any After dryer

Pulp consistency

Head box Couch press After press #1 After press #2 After press #3, if any After press #4, if any After dryer

Is the paper rejected during paper-making repulped and circulated back into the system?

Wastewater treatment plant Is the mill equipped with an operational wastewater treatment plant? If yes, fill in the following table: Type of treatment Primary Secondary (biological)

Description

Capacity (m3/h)

What is the average quantity of wastewater generated by the entire mill, per month or per year? Per day: Per year:

Are there any chemical analyses performed on the raw effluent arriving at the wastewater treatment plant?

Pollution prevention and best practices for the pulp and paper industry

289

If yes, which parameters are analyzed?

What percentage of all the mill's effluent is treated by the wastewater treatment plant?

If the percentage is less than 100%, specify which effluents are not treated:

Does the mill receive wastewater from other sources (factories, apartment buildings, etc.)? If yes, quantify: Wastewater source

Quantity (m3/day)

Are the effluents coming from the mill collected into separate sewers before arriving at the wastewater treatment plant?

What are the chemicals, if any, used to treat the wastewater?

Where are the removed solids disposed of?

What is the total flow rate of the treated effluent?

Is part of the treated effluent recycled back into the process? If yes, in which quantity? Where is the remaining portion of the treated effluent discharged?

290

Handbook of Pollution Prevention and Cleaner Production

Treated effluent monitoring Is the treated effluent sampled manually or automatically?

At what frequency does the mill sample its effluent before discharging?

What are the tests performed on the effluent samples and at which frequency? Parameters

Is the test performed?

Daily

Weekly

Monthly

pH Temperature TSS BOD COD AOX Toxicity

Does the mill measure the quantity of water used per ton of paper produced?

Does the mill correlate COD and TSS per ton of paper produced?

Are the analysis results compared to compliance levels on a daily basis?

What type of equipment is used to measure effluent flow rate?

Is the discharge point equipped with a Parshale flume?

Who, at the mill, receive(s) the monitoring results? Name

Title

Include tables of all the monitoring results for the last 3 months:

Other

Pollution prevention and best practices for the pulp and paper industry

291

References Cheremisinoff, N.P., 2001. Handbook of Pollution Prevention Practices. Marcel Dekker, New York. Grace, T.M., Timmer, W.M., 1995. A Comparison of Alternative Black Liquor Recovery Technologies. TAPPI Proceedings, 1995 International Chemical Recovery Conference, Atlanta, GA. Laadalv, I., 2006. Advances in Black Liquor Gasification. European Conference on Biorefinery Research in Helsinki. http://ec.europa.eu/research/energy/pdf/gp/gp_ events/biorefinery/bs3_02_landalv_en.pdf 19 and 20 October. Nilsson, L.J., Larson, E.D., Gilbreath, K.R., Gupta, A., 1995. Energy Efficiency and the Pulp and Paper Industry. ACEEE, Washington, DC. Palonen, J., Attikoski, T., Eriksson, T., 2005. The Foster Wheeler Gasification Technology for Biofuels: Refuse Derived Fuel (RDF) Power Generation; http://www.fwc. com/publications/tech_papers/files/TP_PC_05_05.pdf Rezaiyan, J., Cheremisinoff, N.P., 2005. Gasification Technologies: A Primer for Engineers and Scientists. Marcel Dekker, New York. TAPPI Journal, 2009. An Assessment of Gasification-based Biorefining at Kraft Pulp and Paper Mills in the United States, Part B: Results. TAPPI Journal, January; abstract, http://www.tappi.org/s_tappi/sec_publications.asp?CID¼11822&DID¼562430 World Bank Organization (WBO), 1998. Pollution Prevention and Abatement Handbook. World Bank Group, Washington, DC. July.

Appendix

Sourcea Pulpboard manufacture Paperboard, general Fiberboard, general

Particleboard manufacture Direct wood-fired rotary dryer, softwood

294

Emission factors for wood manufacturing sectors Method of control

Value

Unit

Measure

Material

VOCs PM, filterable PM10, filterable VOCs

Uncontrolled Uncontrolled Uncontrolled Uncontrolled

2.00E 01 6.00E 01 3.50E 01 2.50E+00

lb lb lb lb

Tons Tons Tons Tons

Finished Finished Finished Finished

Acetaldehyde Acetone Acetophenone Acrolein Benzaldehyde Benzene Biphenyl Butylbenzylphthalate Butyraldehyde Carbon monoxide Carbon sulfide Carbon tetrachloride 3-Carene Dibutyl phthalate Dichloromethane 2,5-Dimethylbenzaldehyde Dioctyl phthalate Ethane Ethylbenzene Formaldehyde Hexanal Hydrocarbons, total, as carbon Hydroquinone Isomers of xylene Isopropylbenzene Isovaleraldehyde

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.30E 8.40E 6.40E 4.50E 2.60E 9.90E 3.90E 1.40E 3.10E 6.80E 1.80E 1.20E 7.60E 2.30E 6.30E 3.30E

02 02 05 03 03 04 05 05 03 01 05 05 02 05 04 05

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

3.20E 04 1.50E 02 3.80E 06 2.50E 02 1.60E 02 1.00E+00

lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

Uncontrolled Uncontrolled Uncontrolled Uncontrolled

6.00E 5.50E 6.90E 5.20E

lb lb lb lb

Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried

05 04 05 04

Action

EF quality

Produced Produced Produced Produced

U E E U

material material material material material material material material material material material material material material material material

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D D D E D D E E C D D D D D E

wood wood wood wood wood wood

material material material material material material

Produced Produced Produced Produced Produced Produced

D D E C E C

wood wood wood wood

material material material material

Produced Produced Produced Produced

E D D E

product product product product

Appendix

Pollutantb

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Multiple cyclones Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

3.40E 02 2.60E 01 1.40E 02 2.80E 05 1.10E 04 4.90E 03 2.40E 03 1.40E 05 2.60E 05 5.80E 01 6.60E 03 3.90E 01 1.20E 01 2.00E 01 3.40E+00 9.30E 01 6.90E 01 3.20E 03 1.20E 04 4.50E 04 2.10E 03 1.20E 05 9.00E 05

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood

material material material material material material material material material material material material material material material material material material material material material material material

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D D D D D D E E D D D D D D D D D E E D D D

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.60E 03 9.00E 01 1.40E 05 5.38E+02 5.90E 01

lb lb lb lb lb

Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood

material material material material material

Produced Produced Produced Produced Produced

E D D D D

Hydrocarbons, total, as carbon NOx PM, condensable PM, filterable PM, filterable VOCs

Uncontrolled

4.80E 02

lb

Tons

Oven-dried wood material

Produced

E

Uncontrolled Uncontrolled Uncontrolled Electrified filter bed Uncontrolled

1.80E+00 4.80E 01 2.20E+00 2.80E 01 5.90E 02

lb lb lb lb lb

Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

Produced Produced Produced Produced Produced

D D D D E

wood wood wood wood wood

material material material material material

295

Continued

Appendix

Direct wood-fired rotary dryer, mixed soft/hardwoods

Limonene Methane Methyl alcohol Methyl bromide Methyl chloride Methyl ethyl ketone Methyl isobutyl ketone Methyl sulfide n-Hexane NOx Phenol a-Pinene b-Pinene PM, condensable PM, filterable PM, filterable PM10, filterable Propionaldehyde Styrene m-Tolualdehyde Toluene 1,1,1-Trichloroethane 1,2,4-Trimethylbenzene Valeraldehyde VOCs o-Xylene Carbon dioxide Carbon monoxide

Pollutantb

Direct wood-fired rotary dryer, hardwoods

Carbon monoxide Hydrocarbons, total, as carbon NOx PM, condensable PM, condensable PM, condensable PM, filterable PM, filterable PM, filterable PM, filterable VOCs Acetaldehyde Acetone Acrolein Benzaldehyde Benzene Butyraldehyde Camphene Carbon dioxide Carbon monoxide 3-Carene Chloroform Crotonaldehyde p-Cymene Dichloromethane 2,5-Dimethylbenzaldehyde Formaldehyde Hexanal Hydrocarbons, total, as carbon Isomers of xylene Isopropylbenzene Isovaleraldehyde

Direct wood-fired rotary dryer, softwood, green (>50% inlet moisture)

Method of control

Value

Unit

Measure

Material

Action

EF quality

Uncontrolled Uncontrolled

5.70E+00 2.00E 01

lb lb

Tons Tons

Oven-dried wood material Oven-dried wood material

Produced Produced

D D

Uncontrolled Uncontrolled Multiple cyclones Wet scrubber Uncontrolled Multiple cyclones Wet scrubber Electrified filter bed Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

9.20E 01 2.10E 01 2.10E 01 2.40E 02 3.30E+00 3.30E+00 9.30E 01 1.90E 01 2.40E 01 7.50E 02 1.90E 01 2.30E 02 1.20E 01 7.60E 03 3.00E 02 4.30E 02 5.73E+02 3.50E+00 4.30E 02 1.00E 04 1.00E 02 2.70E 02 1.80E 03 5.30E 03

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

material material material material material material material material material material material material material material material material

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D D D D D D D E D D E E D E E D D E E E D D E

Uncontrolled Uncontrolled Uncontrolled

1.40E 01 2.20E 02 3.90E+00

lb lb lb

Tons Tons Tons

Oven-dried wood material Oven-dried wood material Oven-dried wood material

Produced Produced Produced

D E D

Uncontrolled Uncontrolled Uncontrolled

4.80E 03 2.00E 03 1.80E 02

lb lb lb

Tons Tons Tons

Oven-dried wood material Oven-dried wood material Oven-dried wood material

Produced Produced Produced

D E E

wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood

material

Appendix

Sourcea

296

Emission factors for wood manufacturing sectorsdcont’d

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Multiple cyclones Uncontrolled Multiple cyclones Fabric filter Electrified filter bed Fabric filter Electrified filter bed Electrified filter bed Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled

4.30E 02 4.30E 02 1.10E 01 6.90E 03 2.70E+00 2.80E 02 1.40E+00 5.20E 01 1.10E+00 1.10E+00 2.20E+00 2.20E+00 1.40E+00 1.50E+00 2.00E 01 2.00E 01 6.40E 01 1.30E 02 3.60E 04 1.70E 01 1.10E 02 2.60E 02 1.30E 02 1.40E 02 4.70E+00 4.50E 04 5.90E 02 4.70E 02 3.30E 03 1.50E 02 8.20E 03 4.70E 03 5.50E 04 6.20E 03 1.30E+00

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood

material material material material material material material material material material material material material material material material material material material material material material material material material material material material material material material material material material material

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E D D D D D D D D D D E E E E E D E E E E D E E E D D E D E D E E D

Thermal oxidizer

1.30E 02

lb

Tons

Oven-dried wood material

Produced

E

297

Continued

Appendix

Direct wood-fired rotary dryer, mixed soft/ hardwoods, green

Limonene 1,5-Menthadiene Methyl alcohol Methyl isobutyl ketone NOx Phenol a-Pinene b-Pinene PM, condensable PM, condensable PM, filterable PM, filterable PM, filterable PM, filterable PM, filterable PM, filterable PM10, filterable Propionaldehyde Styrene Terpene o-Tolualdehyde p-Tolualdehyde Toluene Valeraldehyde VOCs o-Xylene Acetaldehyde Acetone Acetone Acrolein Benzaldehyde Benzene Benzene Hexanal Hydrocarbons, total, as carbon Hydrocarbons, total, as carbon

Sourcea

Isomers of xylene Isomers of xylene Isovaleraldehyde Methyl alcohol Methyl alcohol Methyl ethyl ketone NOx Phenol a-Pinene b-Pinene PM, condensable PM, filterable PM, filterable PM, filterable PM, filterable PM, filterable PM10, filterable Propionaldehyde Styrene Styrene Terpene o-Tolualdehyde p-Tolualdehyde Toluene Toluene Valeraldehyde VOCs VOCs o-Xylene o-Xylene Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol PM, condensable

Method of control

Value

Unit

Measure

Material

Action

EF quality

Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Multiple cyclones Fabric filter Electrified filter bed Fabric filter Electrified filter bed Electrified filter bed Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled

5.80E 03 7.50E 04 1.10E 03 5.90E 02 1.90E 03 3.40E 03 1.40E+00 7.90E 03 5.10E 01 1.10E 01 6.20E 01 2.00E+00 1.30E+00 2.70E 01 1.50E 01 1.50E 01 1.10E 01 4.20E 03 5.70E 04 7.40E 04 5.30E 02 6.60E 04 4.60E 03 5.90E 03 6.50E 04 4.00E 03 1.60E+00 1.30E 02 5.80E 04 7.50E 04 8.60E 03 1.60E+00

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

material material material material material material material material material material material material material material material material material material material material material material material material material material material material material material material material

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D E E D E D E D D D D E E E E E D D D E E E E D E E E E D E E D

Uncontrolled Uncontrolled

7.30E 02 1.20E 01

lb lb

Tons Tons

Oven-dried wood material Oven-dried wood material

Produced Produced

E D

wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood

Appendix

Direct natural gas-fired rotary dryer, softwood

Pollutantb

298

Emission factors for wood manufacturing sectorsdcont’d

Direct natural gas-fired rotary dryer, hardwood

Indirect natural gas-heated rotary dryer, softwood

Direct wood-fired tube dryer, hardwood, blowline blend, UF resin Batch hot press, UF resin

Acetaldehyde Acetone Acrolein Benzaldehyde Benzene Butyraldehyde Camphene

Multiple cyclones Uncontrolled Multiple cyclones Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.20E 01 4.20E 01 4.20E 01 2.00E+00 2.37E+02 4.20E 03 7.70E 01

lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood

material material material material material material material

Produced Produced Produced Produced Produced Produced Produced

D D D E D E E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

9.40E 01 3.11E+02 1.20E+00 2.80E 02 2.10E 01

lb lb lb lb lb

Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood

material material material material material

Produced Produced Produced Produced Produced

E E E E E

Uncontrolled Uncontrolled Multiple cyclones Electrified filter bed Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

2.40E 02 1.50E 01 2.20E+00 3.10E 01 2.80E 01 3.82E+01 1.20E 01 4.70E 02 4.30E 01

lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood wood wood

material material material material material material material material material

Produced Produced Produced Produced Produced Produced Produced Produced Produced

E D E E E D D D D

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

2.70E 01 2.70E 02 3.10E 01 3.00E 01 4.47E+02

lb lb lb lb lb

Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood

material material material material material

Produced Produced Produced Produced Produced

D D D E E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.10E 2.90E 5.40E 1.80E 3.00E 1.90E 4.40E

lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000

Produced Produced Produced Produced Produced Produced Produced

D D D E D E D

02 02 03 03 03 03 02

ft2 ft2 ft2 ft2 ft2 ft2 ft2

3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick

panel panel panel panel panel panel panel

299

Continued

Appendix

Direct natural gas-fired rotary dryer, softwood, green (>50% moisture)

PM, condensable PM, filterable PM, filterable VOCs Carbon dioxide Formaldehyde Hydrocarbons, total, as carbon VOCs Carbon dioxide Carbon monoxide Formaldehyde Hydrocarbons, total, as carbon NOx PM, condensable PM, filterable PM, filterable VOCs Carbon dioxide Carbon monoxide Formaldehyde Hydrocarbons, total, as carbon Methane Methyl alcohol NOx VOCs Carbon dioxide

300

Emission factors for wood manufacturing sectorsdcont’d

Sourcea

Pollutantb

Value

Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled Uncontrolled

2.20E 9.00E 3.60E 5.00E 3.50E 3.20E

Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled

2.30E 5.40E 1.00E 7.90E

Action

EF quality

panel panel panel panel panel panel

Produced Produced Produced Produced Produced Produced

D D D E D E

panel panel panel panel

Produced Produced Produced Produced

C D E C

3/4-inch-thick panel

Produced

E

3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E D D D D D E E D E D D D D E E D E

Unit

Measure

01 02 02 04 02 04

lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2

3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick

01 03 02 01

lb lb lb lb

1000 1000 1000 1000

ft2 ft2 ft2 ft2

3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick

Thermal oxidizer

1.80E 02

lb

1000 ft2

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Thermal oxidizer

1.10E 03 3.60E 02 3.60E 02 5.90E 01 5.20E 03 9.90E 03 1.70E 02 9.20E 02 1.10E 02 8.20E 03 4.00E 01 1.10E 01 2.30E 01 2.00E 01 1.60E 02 3.90E 03 1.10E+00 2.70E 02

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

Material

panel panel panel panel panel panel panel panel panel panel panel panel panel panel panel panel panel panel

Appendix

Carbon monoxide Carbon monoxide 3-Carene Crotonaldehyde p-Cymene 2,5-Dimethylbenzaldehyde Formaldehyde Formaldehyde Hexanal Hydrocarbons, total, as carbon Hydrocarbons, total, as carbon Isovaleraldehyde Limonene 1,5-Menthadiene Methyl alcohol Methyl ethyl ketone Methyl isobutyl ketone NOx NOx Phenol Phenol a-Pinene b-Pinene PM, condensable PM, filterable PM10, filterable Valeraldehyde VOCs VOCs

Method of control

Particleboard board cooler, UF resin

Flaker/refiner/hammermill, softwoods and mixtures containing softwoods

Acetaldehyde Butyraldehyde Formaldehyde Hexanal Methyl ethyl ketone a-Pinene b-Pinene Toluene 1,1,1-Trichloroethane Acetaldehyde Acetone Acrolein Benzaldehyde Butyraldehyde Carbon monoxide Crotonaldehyde Formaldehyde Hexanal Hydrocarbons, total, as carbon Isovaleraldehyde Methyl alcohol Methyl ethyl ketone Methyl isobutyl ketone Phenol a-Pinene PM, condensable PM, filterable Valeraldehyde VOCs Acetone Hydrocarbons, total, as carbon Methyl alcohol Phenol a-Pinene

Uncontrolled

9.90E 05

lb

1000 ft2 2

3/4-inch-thick panel

Produced

E

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E E E E E E D D E E E D E D E D

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.40E 6.20E 1.70E 2.00E 5.40E 1.10E 4.70E 2.20E 3.60E 8.30E 3.60E 4.20E 6.00E 1.50E 2.90E 1.50E 1.10E 6.90E

04 03 04 04 04 04 04 04 03 03 04 04 04 01 04 02 03 02

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000

ft ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick 3/4-inch-thick

panel panel panel panel panel panel panel panel panel panel panel panel panel panel panel panel panel panel

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

4.00E 8.10E 1.10E 3.20E 6.60E 5.00E 7.70E 1.50E 1.50E 9.10E 6.40E 9.40E

04 02 04 03 03 02 02 01 03 02 03 01

lb lb lb lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 Tons Tons

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

3/4-inch-thick panel 3/4-inch-thick panel 3/4-inch-thick panel 3/4-inch-thick panel 3/4-inch-thick panel 3/4-inch-thick panel 3/4-inch-thick panel 3/4-inch-thick panel 3/4-inch-thick panel 3/4-inch-thick panel Oven-dried wood material Oven-dried wood material

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E D E E D D D D E E D D

Uncontrolled Uncontrolled Uncontrolled

7.30E 03 4.50E 03 4.90E 01

lb lb lb

Tons Tons Tons

Oven-dried wood material Oven-dried wood material Oven-dried wood material

Produced Produced Produced

D E D

Appendix

Veneer press, UF resin

Continued

301

Sourcea

Sander

Plywood operations Hardwood plywood, veneer dryer, direct wood-fired, heated zones

Hardwood plywood, veneer dryer, direct wood-fired, cooling section Softwood plywood, veneer dryer, direct wood-fired, heated zones

Method of control

Value

Unit

Measure

Material

Action

EF quality

b-Pinene VOCs Acetone Hydrocarbons, total, as carbon Methyl alcohol Phenol a-Pinene VOCs

Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.50E 01 1.10E+00 5.10E 03 6.90E 02

lb lb lb lb

Tons Tons 1000 ft2 1000 ft2

Oven-dried wood material Oven-dried wood material Panel Panel

Produced Produced Produced Produced

D E E E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.30E 1.50E 4.80E 7.90E

02 02 02 02

lb lb lb lb

1000 1000 1000 1000

ft2 ft2 ft2 ft2

Panel Panel Panel Panel

Produced Produced Produced Produced

E E E E

Acetaldehyde Acetone Carbon monoxide Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol VOCs Hydrocarbons, total, as carbon VOCs Carbon dioxide Carbon monoxide Formaldehyde Hydrocarbons, total, as carbon NOx PM, filterable

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

5.20E 4.50E 2.30E 2.50E 5.30E

03 03 01 03 02

lb lb lb lb lb

1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

veneer veneer veneer veneer veneer

Produced Produced Produced Produced Produced

E E E E E

Uncontrolled Uncontrolled Uncontrolled

9.50E 03 6.30E 02 3.70E 03

lb lb lb

1000 ft2 1000 ft2 1000 ft2

3/8-inch-thick veneer 3/8-inch-thick veneer 3/8-inch-thick veneer

Produced Produced Produced

E E E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

4.50E 03 1.00E+02 3.20E+00 4.50E 02 8.30E 01

lb lb lb lb lb

1000 1000 1000 1000 1000

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

veneer veneer veneer veneer veneer

Produced Produced Produced Produced Produced

E D D D D

Uncontrolled Wet electrostatic precipitator Uncontrolled Uncontrolled Catalytic oxidizer Uncontrolled Catalytic oxidizer

1.70E 01 2.40E 01

lb lb

1000 ft2 1000 ft2

3/8-inch-thick veneer 3/8-inch-thick veneer

Produced Produced

D D

1.10E+00 6.20E 02 6.10E 02 5.90E 02 4.80E 02

lb lb lb lb lb

1000 1000 1000 1000 1000

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

Produced Produced Produced Produced Produced

E D E D E

Pollutantb

VOCs Acetaldehyde Acetaldehyde Acetone Acetone

ft2 ft2 ft2 ft2 ft2

ft2 ft2 ft2 ft2 ft2

veneer veneer veneer veneer veneer

Appendix

Softwood plywood, veneer dryer, direct natural gasfired, heated zones

302

Emission factors for wood manufacturing sectorsdcont’d

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Catalytic oxidizer Uncontrolled Catalytic oxidizer Uncontrolled

9.00E 03 5.70E 03 2.80E+01 6.40E 01 7.60E 03 6.40E 02 3.80E 02 2.10E+00

lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000

Catalytic oxidizer

3.00E 01

lb

1000 ft2 2

3.90E 03 8.10E 02 6.70E 02 3.60E 02 4.90E 03 1.90E 03 2.60E 03 1.20E 02 6.00E 03 5.50E 03 1.00E+00 4.10E 01 4.20E 01 7.90E 02 1.60E 03 1.50E 03 7.40E 03 2.50E+00 3.60E 01 3.40E 03 4.10E 03 1.00E 02 1.50E 03 3.80E 02

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000

ft ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

Uncontrolled Uncontrolled Uncontrolled

5.70E 03 1.00E 02 4.40E 02

lb lb lb

1000 ft2 1000 ft2 1000 ft2

veneer veneer veneer veneer veneer veneer veneer veneer

Produced Produced Produced Produced Produced Produced Produced Produced

D D D D E D E D

3/8-inch-thick veneer

Produced

E

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D D D E D D D D E D D D D D D D E E E E E E E

3/8-inch-thick veneer 3/8-inch-thick veneer 3/8-inch-thick veneer

Produced Produced Produced

E E E Continued

303

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Catalytic oxidizer Uncontrolled Uncontrolled Uncontrolled Uncontrolled Catalytic oxidizer Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Catalytic oxidizer Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

Appendix

Softwood plywood, veneer dryer, direct natural gas-fired, cooling section

Acrolein Benzene Carbon dioxide Carbon monoxide Carbon monoxide Formaldehyde Formaldehyde Hydrocarbons, total, as carbon Hydrocarbons, total, as carbon Isomers of xylene Limonene Methane Methyl alcohol Methyl alcohol Methyl ethyl ketone Methyl isobutyl ketone NOx Phenol Phenol a-Pinene b-Pinene PM, condensable PM, filterable Propionaldehyde Styrene Toluene VOCs VOCs Acetaldehyde Acetone Carbon monoxide Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol Phenol VOCs

Pollutantb

Hardwood plywood, veneer dryer, indirect-heated, heated zones

Acetaldehyde Acetone Carbon monoxide Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol Methyl isobutyl ketone Phenol VOCs Acetaldehyde Acetone Carbon monoxide Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol Methyl isobutyl ketone VOCs Acetaldehyde Acetaldehyde Acetone Acetone Acrolein Benzene Benzene Carbon monoxide Carbon monoxide 3-Carene Formaldehyde Formaldehyde Hydrocarbons, total, as carbon Hydrocarbons, total, as carbon

Hardwood plywood, veneer dryer, indirect-heated, cooling section

Softwood plywood, veneer dryer, indirect-heated, heated zones

Method of control

Value

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

4.30E 4.00E 8.80E 1.10E 2.30E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

4.10E 2.20E 3.00E 2.80E 3.20E 4.70E 9.90E 6.50E 6.20E

Action

EF quality

veneer veneer veneer veneer veneer

Produced Produced Produced Produced Produced

D D E D D

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

veneer veneer veneer veneer veneer veneer veneer veneer veneer

Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D D E D D E D D

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D E C D C D C C E E E C C D B

3/8-inch-thick veneer

Produced

D

Unit

Measure

Material

03 03 03 03 01

lb lb lb lb lb

1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

02 03 03 01 02 02 02 03 01

lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled

2.10E 02 2.90E 02 7.20E 01 1.70E 02 1.90E 03 1.30E 02 1.70E 03 1.30E 03 5.90E 04 4.00E 04 2.80E 02 6.20E 02 4.00E 02 1.40E 02 2.30E 03 1.50E+00

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

Thermal oxidizer

1.40E 01

lb

1000 ft2

Appendix

Sourcea

304

Emission factors for wood manufacturing sectorsdcont’d

Softwood plywood, veneer dryer, radiofrequencyheated

Softwood plywood press, PF resin

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

7.50E 04 8.00E 02 1.70E 02 3.90E 02 2.30E 03 1.50E 03 3.40E 03 5.00E 03 9.60E 01 2.60E 02 2.70E 01 1.00E+00 3.50E 01 1.00E 02 5.40E 03 6.20E 03 4.90E 02 5.40E 02 1.40E 03 1.50E 03 8.90E 04 3.50E 04 2.30E 01

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer veneer

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

C C C C D C C D C D C D D D D D D E D D D D D

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

4.00E 2.70E 1.70E 5.60E 6.00E 5.00E 2.80E 4.20E 6.50E 1.90E 2.10E

03 03 01 02 03 03 01 03 03 03 01

lb lb lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

veneer veneer veneer veneer veneer veneer veneer panel panel panel panel

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D D D E E E D D D D

Uncontrolled Uncontrolled

1.10E 02 1.40E 01

lb lb

1000 ft2 1000 ft2

Produced Produced

D D

3/8-inch-thick panel 3/8-inch-thick panel

305

Continued

Appendix

Softwood plywood, veneer dryer, indirect-heated, cooling section

Isomers of xylene Limonene 1,5-Menthadiene Methyl alcohol Methyl alcohol Methyl isobutyl ketone Phenol Phenol a-Pinene a-Pinene b-Pinene PM, condensable PM, filterable Methyl alcohol Methyl isobutyl ketone Phenol a-Pinene VOCs o-Xylene Acetaldehyde Acetone Formaldehyde Hydrocarbons, total, as carbon Limonene Methyl alcohol a-Pinene b-Pinene PM, condensable PM, filterable VOCs Acetaldehyde Acetone Formaldehyde Hydrocarbons, total, as carbon Limonene Methyl alcohol

Sourcea

Hardwood plywood press, UF resin

Hardwood plywood, combined dust BH, trim and core saws, composer, dry hog, hammermill. Softwood plywood, log steaming vat

Softwood plywood, dry veneer trim chipper

Pollutantb

Value

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

8.70E 7.10E 1.40E 9.80E 3.80E 8.30E 1.20E 2.50E 2.50E 4.70E 5.50E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

Action

EF quality

panel panel panel panel panel panel panel panel panel panel panel

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D D D D D D E D D D

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

panel panel panel panel panel panel

Produced Produced Produced Produced Produced Produced

D D D E U U

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

panel panel panel panel panel panel panel panel panel panel panel

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

U U U U U U U U U U U

ft2 ft2 ft2 ft2

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

panel panel panel panel

Produced Produced Produced Produced

U U U U

Unit

Measure

Material

04 04 03 02 02 02 01 01 02 03 02

lb lb lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

3.20E 5.70E 1.10E 4.70E 8.90E 1.90E

02 03 02 02 03 02

lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

2.90E 1.40E 4.70E 3.00E 7.30E 5.60E 6.40E 8.10E 8.20E 3.40E 5.90E

03 02 03 03 03 02 03 04 04 04 02

lb lb lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000

Uncontrolled Uncontrolled Uncontrolled Uncontrolled

8.70E 1.90E 3.20E 7.20E

03 03 02 02

lb lb lb lb

1000 1000 1000 1000

Appendix

Methyl ethyl ketone Methyl isobutyl ketone Phenol a-Pinene b-Pinene PM, condensable PM, filterable VOCs Acetone Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol Methyl isobutyl ketone Phenol VOCs Acetone Hydrocarbons, total, as carbon Methyl alcohol VOCs Acetaldehyde Acetone Methyl alcohol a-Pinene b-Pinene Acetaldehyde Acetone Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol Phenol a-Pinene VOCs

Method of control

306

Emission factors for wood manufacturing sectorsdcont’d

Softwood plywood, sanders and specialty saw

Softwood plywood, saws, hog, and sander

Hydrocarbons, total, as carbon Methyl alcohol a-Pinene VOCs Acetaldehyde Acetone Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol a-Pinene VOCs Acetaldehyde Acetone Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol a-Pinene VOCs

Medium-density fiberboard (MDF) manufacture Direct wood-fired tube dryer, Carbon monoxide Formaldehyde blowline blend, UF resin, Hydrocarbons, softwoods total, as carbon PM, condensable PM, filterable PM10, filterable VOCs Acetone Direct natural gas-fired tube Carbon monoxide dryer, nonblowline blend, Formaldehyde hardwoods Hydrocarbons, total, as carbon Methyl alcohol VOCs

Uncontrolled

5.60E 02

lb

1000 ft2

3/8-inch-thick panel

Produced

U

2

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

7.80E 3.60E 6.80E 2.80E 4.70E 1.80E 1.50E

03 02 02 03 03 03 01

lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000

ft ft2 ft2 ft2 ft2 ft2 ft2

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

panel panel panel panel panel panel panel

Produced Produced Produced Produced Produced Produced Produced

U U U U U U U

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.20E 2.30E 1.80E 9.20E 1.90E 3.40E 7.20E

02 02 01 04 03 04 02

lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2 ft2

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

panel panel panel panel panel panel panel

Produced Produced Produced Produced Produced Produced Produced

U U U U U U U

Uncontrolled Uncontrolled Uncontrolled

1.20E 02 2.70E 02 8.60E 02

lb lb lb

1000 ft2 1000 ft2 1000 ft2

3/8-inch-thick panel 3/8-inch-thick panel 3/8-inch-thick panel

Produced Produced Produced

U U U

Uncontrolled Uncontrolled Uncontrolled

4.00E+00 8.60E 01 4.80E+00

lb lb lb

Tons Tons Tons

Oven-dried wood material Oven-dried wood material Oven-dried wood material

Produced Produced Produced

D D D

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

5.90E 01 1.04E+01 1.60E+00 6.70E+00 1.60E 02 2.00E 01 8.50E 03 1.00E+00

lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

material material material material material material material material

Produced Produced Produced Produced Produced Produced Produced Produced

D D D E D D D D

Uncontrolled Uncontrolled

9.60E 01 1.20E+00

lb lb

Tons Tons

Oven-dried wood material Oven-dried wood material

Produced Produced

D E

wood wood wood wood wood wood wood wood

307

Continued

Appendix

Softwood plywood, dry plywood trim chippers

Sourcea

Pollutantb

Indirect-heated tube dryer, blowline blend, UF resin, softwoods

Acetaldehyde Acetaldehyde Acetone Camphene Carbon monoxide Carbon monoxide Formaldehyde Formaldehyde Hydrocarbons, total, as carbon Limonene Methyl alcohol Methyl isobutyl ketone NOx Phenol a-Pinene b-Pinene PM, condensable PM, condensable PM, condensable PM, condensable PM10, PM10, PM10, PM10,

Indirect-heated tube dryer, nonblowline blend, softwoods

filterable filterable filterable filterable

VOCs Acetone Carbon monoxide

Method of control

Value

Unit

Measure

Material

Action

EF quality

Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled

2.00E 02 5.10E 03 2.50E 02 1.20E 01 6.80E 02 1.60E+00 2.20E 01 1.50E 01 4.40E+00

lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood wood wood

material material material material material material material material material

Produced Produced Produced Produced Produced Produced Produced Produced Produced

D E D D D E C E D

Uncontrolled Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled Uncontrolled Fabric filter Fabric filter Wet electrostatic precipitator Uncontrolled Fabric filter Fabric filter Wet electrostatic precipitator Uncontrolled Uncontrolled Uncontrolled

1.10E 01 8.70E 01 4.90E 03 3.80E 01 2.30E 02 2.10E+00 4.30E 01 5.30E 01 1.40E 01 1.30E 01 1.30E 01

lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood wood wood wood wood

material material material material material material material material material material material

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D D E D D D D D D D

6.00E 1.10E 1.30E 1.30E

01 02 02 02

lb lb lb lb

Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood

material material material material

Produced Produced Produced Produced

D D D D

5.60E+00 5.50E 02 1.10E 01

lb lb lb

Tons Tons Tons

Oven-dried wood material Oven-dried wood material Oven-dried wood material

Produced Produced Produced

E D D

Uncontrolled Uncontrolled

8.50E 02 1.70E+00

lb lb

Tons Tons

Oven-dried wood material Oven-dried wood material

Produced Produced

D D

Uncontrolled Uncontrolled

7.40E 01 2.10E+00

lb lb

Tons Tons

Oven-dried wood material Oven-dried wood material

Produced Produced

D E

Appendix

Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol VOCs

308

Emission factors for wood manufacturing sectorsdcont’d

Indirect-heated second-stage tube dryer, blowline blend, softwoods

Acetaldehyde Formaldehyde Hydrocarbons, total, as carbon VOCs Acetaldehyde Acetone Benzene Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol a-Pinene Toluene VOCs

Oriented strandboard (OSB) manufacture Hot press, MDI resin Carbon monoxide Formaldehyde Hydrocarbons, total, as carbon Methylene(B)4phenylisocyanate NOx Medium-density fiberboard (MDF) manufacture Direct natural gas-fired rotary Acetone predryer, softwoods Carbon monoxide Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol a-Pinene VOCs Batch hot press, UF resin Acetaldehyde Acetone Acrolein

Uncontrolled Uncontrolled Uncontrolled

1.30E 02 2.60E 01 3.70E+00

lb lb lb

Tons Tons Tons

Oven-dried wood material Oven-dried wood material Oven-dried wood material

Produced Produced Produced

D C D

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

4.80E+00 3.50E 03 3.40E 03 7.30E 04 2.10E 02 1.30E 01

lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood

material material material material material material

Produced Produced Produced Produced Produced Produced

E D D D D D

Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.50E 5.50E 8.30E 1.80E

02 02 04 01

lb lb lb lb

Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood

material material material material

Produced Produced Produced Produced

D D D E

Uncontrolled Uncontrolled Uncontrolled

1.10E 01 6.40E 02 1.10E 01

lb lb lb

1000 ft2 1000 ft2 1000 ft2

3/8-inch-thick panel 3/8-inch-thick panel 3/8-inch-thick panel

Produced Produced Produced

D D D

Uncontrolled

2.10E 03

lb

1000 ft2

3/8-inch-thick panel

Produced

E

2

3/8-inch-thick panel

Produced

D

1.90E 02

lb

1000 ft

Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.90E 2.40E 7.60E 7.90E

02 01 03 01

lb lb lb lb

Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried

material material material material

Produced Produced Produced Produced

D D D D

Uncontrolled Uncontrolled Uncontrolled Uncontrolled

2.50E 2.80E 9.50E 1.40E

02 01 01 02

lb lb lb lb

Tons Tons Tons 1000 ft2

Produced Produced Produced Produced

D D E D

Uncontrolled

2.90E 02

lb

1000 ft2

Produced

D

lb

2

Oven-dried wood material Oven-dried wood material Oven-dried wood material 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard

Produced

E

Uncontrolled

1.20E 03

1000 ft

wood wood wood wood

309

Uncontrolled

Appendix

Indirect-heated tube dryer, blowline blend, UF resin, hardwoods

Continued

Sourcea

310

Emission factors for wood manufacturing sectorsdcont’d Method of control

Value

Unit

Measure

Material

Action

EF quality

Benzaldehyde

Uncontrolled

5.50E 04

lb

1000 ft2

E

lb

1000 ft

Produced

E

2

3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard

Produced

2

Produced

E

Produced

E

Produced

E

Produced

E

Produced

C

Produced

E

Produced

E

Produced

D

Produced

E

Produced

E

Produced

D

Produced

D

Produced

E

Produced

D

Produced

E

Produced

E

Butyraldehyde

Uncontrolled

2.40E 03

Carbon monoxide

Uncontrolled

3.40E 02

lb

1000 ft

Carbon monoxide

Thermal oxidizer

8.50E 02

lb

1000 ft2

Crotonaldehyde

Uncontrolled

1.10E 03

lb

1000 ft2

lb

1000 ft

2

1000 ft

2

2

2,5-Dimethylbenzaldehyde Formaldehyde

Uncontrolled Uncontrolled

2.50E 03 4.80E 01

lb

Formaldehyde

Thermal oxidizer

9.10E 03

lb

1000 ft

Hexanal

Uncontrolled

2.90E 03

lb

1000 ft2

Hydrocarbons, total, as carbon Hydrocarbons, total, as carbon Isovaleraldehyde

Uncontrolled

2.90E 01

lb

1000 ft2

lb

1000 ft

2

Uncontrolled

1.40E 03

lb

1000 ft

2

Methyl alcohol

Uncontrolled

5.60E 01

lb

1000 ft2

PM, filterable

Uncontrolled

1.80E 01

lb

1000 ft2

lb

1000 ft

2

2

PM, filterable

Thermal oxidizer

Thermal oxidizer

1.90E 02

4.00E 02

PM10, filterable

Uncontrolled

1.50E 01

lb

1000 ft

Propionaldehyde

Uncontrolled

5.40E 04

lb

1000 ft2

o-Tolualdehyde

Uncontrolled

7.00E 04

lb

1000 ft2

Appendix

Pollutantb

MDF board cooler, UF resin

Uncontrolled

1.00E 03

lb

1000 ft2 2

Valeraldehyde

Uncontrolled

2.40E 03

lb

1000 ft

VOCs

Uncontrolled

8.00E 01

lb

1000 ft2

VOCs

Thermal oxidizer

3.20E 02

lb

1000 ft2

lb

1000 ft

2

2

Acetaldehyde

Uncontrolled

1.00E 03

Acetone

Uncontrolled

9.20E 03

lb

1000 ft

Acrolein

Uncontrolled

2.20E 04

lb

1000 ft2

Benzaldehyde

Uncontrolled

9.90E 05

lb

1000 ft2

lb

1000 ft

2

2

Butyraldehyde

Uncontrolled

1.40E 03

Crotonaldehyde

Uncontrolled

2.60E 04

lb

1000 ft

2,5-Dimethylbenzaldehyde Formaldehyde

Uncontrolled

1.90E 04

lb

1000 ft2

Uncontrolled

4.20E 02

lb

1000 ft2

lb

1000 ft

2

2

Hexanal

Uncontrolled

6.50E 04

Hydrocarbons, total, as carbon Isovaleraldehyde

Uncontrolled

7.70E 02

lb

1000 ft

Uncontrolled

2.50E 04

lb

1000 ft2

Methyl alcohol

Uncontrolled

2.50E 02

lb

1000 ft2

lb

1000 ft

2

1000 ft

2

1000 ft

2

Methyl ethyl ketone PM, filterable PM10, filterable

Uncontrolled Uncontrolled Uncontrolled

1.10E 04 5.40E 02 3.80E 03

lb lb

3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

D

Produced

E

Produced

D

Produced

E

Produced

E

Produced

E

Produced

D

Produced

E

311

Continued

Appendix

p-Tolualdehyde

Emission factors for wood manufacturing sectorsdcont’d

Paddle blender, UF resin Former without blowline blend, UF resin (includes blender emissions) Former with blowline blend, UF resin

Sander

Saw and hogger (pulverizer)

Pollutantb

Method of control

Value

Unit

Measure

Material

Action

EF quality

o-Tolualdehyde

Uncontrolled

6.50E 05

lb

1000 ft2

Produced

E

p-Tolualdehyde

Uncontrolled

1.70E 04

lb

1000 ft2

Produced

E

Valeraldehyde

Uncontrolled

4.80E 04

lb

1000 ft2

Produced

E

2

Produced

E

Produced Produced

E E

Uncontrolled

1.30E 01

lb

1000 ft

Formaldehyde Methyl alcohol

Uncontrolled Uncontrolled

1.00E 02 4.80E 01

lb lb

Tons Tons

Acetone Formaldehyde

Uncontrolled Uncontrolled

5.30E 02 6.00E 02

lb lb

Tons Tons

Oven-dried wood material Oven-dried wood material

Produced Produced

E E

Methyl alcohol Acetone

Uncontrolled Uncontrolled

4.10E 01 6.40E 03

lb lb

Tons Tons

Oven-dried wood material Oven-dried wood material

Produced Produced

E D

Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol VOCs Acetone Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol Phenol Styrene VOCs Hydrocarbons, total, as carbon Methyl alcohol

Uncontrolled Uncontrolled

5.10E 03 5.60E 02

lb lb

Tons Tons

Oven-dried wood material Oven-dried wood material

Produced Produced

D E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.70E 6.70E 5.10E 2.70E 7.40E

02 02 03 03 03

lb lb lb lb lb

Tons Tons 1000 ft2 1000 ft2 1000 ft2

Oven-dried wood material Oven-dried wood material Panel Panel Panel

Produced Produced Produced Produced Produced

D E D D E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

4.30E 6.90E 1.40E 6.60E 1.10E

03 03 03 03 01

lb lb lb lb lb

1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2

Panel Panel Panel Panel Material

D D D E E

Uncontrolled

3.80E 01

lb

1000 ft2

Material

lb

2

Material

Produced Produced Produced Produced Reclaimed (trimmed) Reclaimed (trimmed) Reclaimed (trimmed)

VOCs

Uncontrolled

1.30E 01

1000 ft

E E

Appendix

VOCs

3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard Oven-dried wood material Oven-dried wood material

312

Sourcea

1.10E 01 1.10E 02 1.60E 01 7.60E 03 7.20E 02 6.70E 03 6.80E 02 6.00E+02 7.20E+02 5.30E+00 1.80E+00 6.60E 02 6.70E 02 2.20E 03

lb lb lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood wood wood wood wood wood wood wood

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D D D D D D C D B D D D D

Uncontrolled Thermal oxidizer Uncontrolled

1.30E 01 2.00E 02 6.70E+00

lb lb lb

Tons Tons Tons

Oven-dried wood Oven-dried wood Oven-dried wood

Produced Produced Produced

B D B

Thermal oxidizer

2.50E 01

lb

Tons

Oven-dried wood

Produced

D

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled Multiple cyclones Thermal oxidizer

1.00E 02 5.50E 02 1.40E 01 6.30E 02 1.00E 01 8.20E 03 8.90E 03 7.80E 03 7.00E 01 7.80E 01 1.50E 02 2.10E 02 2.90E+00 1.00E+00 1.50E+00 5.10E 01 1.00E 01

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D D D D D D D C D D D D D C B D

wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood

Continued

313

Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled

Appendix

Oriented strandboard (OSB) manufacture Acetaldehyde Direct wood-fired Acetaldehyde rotary dryer, Acetone softwoods Acetone Acrolein Benzene Camphene Carbon dioxide Carbon dioxide Carbon monoxide Carbon monoxide 3-Carene p-Cymene 1,2-Dichloroethylene, cis Formaldehyde Formaldehyde Hydrocarbons, total, as carbon Hydrocarbons, total, as carbon Isomers of xylene Isopropylbenzene Limonene 1,5-Menthadiene Methyl alcohol Methyl alcohol Methyl ethyl ketone Methyl isobutyl ketone NOx NOx Phenol Phenol a-Pinene b-Pinene PM, condensable PM, condensable PM, condensable

Sourcea

Pollutantb PM, condensable PM, condensable PM, condensable PM, PM, PM, PM, PM,

condensable filterable filterable filterable filterable

PM, filterable PM, filterable

Direct wood-fired rotary dryer, hardwoods

Wet electrostatic precipitator Thermal oxidizer Wet electrostatic precipitator Electrified filter bed Uncontrolled Multiple cyclones Thermal oxidizer Wet electrostatic precipitator Thermal oxidizer Wet electrostatic precipitator Electrified filter bed Uncontrolled Uncontrolled Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer

Value

Unit

Measure

Material

Action

EF quality

4.60E 01

lb

Tons

Oven-dried wood

Produced

D

9.80E 02 9.80E 02

lb lb

Tons Tons

Oven-dried wood Oven-dried wood

Produced Produced

E E

4.80E 01 4.10E+00 2.30E+00 3.00E 01 4.30E 01

lb lb lb lb lb

Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood

Produced Produced Produced Produced Produced

D C C D D

5.10E 02 5.10E 02

lb lb

Tons Tons

Oven-dried wood Oven-dried wood

Produced Produced

E E

5.60E 01 2.50E+00 1.10E 02 1.50E 02 8.10E+00 3.20E 01 6.20E 01 1.10E 01 4.10E 02 1.20E 02 2.00E 01 3.10E 02 1.00E 02 4.10E 03 6.80E+02 7.80E+02 5.50E+00 1.50E+00 1.10E 01 9.20E 02

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D D D C E E E E E E E D D B C B D B D

wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood

Appendix

PM, filterable PM10, filterable Propionaldehyde Toluene VOCs VOCs Acetaldehyde Acetaldehyde Acetone Acetone Acrolein Acrolein Benzene Benzene Carbon dioxide Carbon dioxide Carbon monoxide Carbon monoxide Formaldehyde Formaldehyde

Method of control

314

Emission factors for wood manufacturing sectorsdcont’d

PM, condensable PM, condensable PM, PM, PM, PM,

condensable filterable filterable filterable

PM, filterable PM, filterable PM, filterable PM, filterable PM, filterable PM10, filterable Propionaldehyde Propionaldehyde Styrene Sulfur dioxide Toluene VOCs VOCs

Uncontrolled

1.70E+00

lb

Tons

Oven-dried wood

Produced

B

Thermal oxidizer

1.50E 01

lb

Tons

Oven-dried wood

Produced

D

Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Multiple cyclones Wet electrostatic precipitator Thermal oxidizer Wet electrostatic precipitator Electrified filter bed Uncontrolled Multiple cyclones Wet electrostatic precipitator Thermal oxidizer Wet electrostatic precipitator Electrified filter bed Thermal oxidizer Electrified filter bed Electrified filter bed Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Thermal oxidizer

3.30E 01 7.20E 02 7.10E 03 6.30E 01 4.20E 01 2.80E 02 8.50E 03 1.90E+00 3.80E 01 3.80E 01

lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood wood wood wood

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E B D E D E E D

1.20E 01 1.20E 01

lb lb

Tons Tons

Oven-dried wood Oven-dried wood

Produced Produced

E E

4.50E 01 4.20E+00 5.20E+00 2.50E 01

lb lb lb lb

Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood

Produced Produced Produced Produced

C D D C

4.90E 02 4.90E 02

lb lb

Tons Tons

Oven-dried wood Oven-dried wood

Produced Produced

D D

9.30E 01 5.10E 01 5.10E 01 1.00E+00 3.40E 02 7.50E 03 3.40E 03 1.40E 02 1.30E 02 2.10E+00 2.60E 01

lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

C D D D E E E E E C E

wood wood wood wood wood wood wood wood wood wood wood

315

Continued

Appendix

Hydrocarbons, total, as carbon Hydrocarbons, total, as carbon Methyl alcohol Methyl alcohol Methyl ethyl ketone NOx NOx Phenol Phenol PM, condensable PM, condensable PM, condensable

316

Emission factors for wood manufacturing sectorsdcont’d

Sourcea

Pollutantb

Direct wood-fired rotary dryer, mixed (40–60% softwood, 40–60% hardwood)

Acetaldehyde Acetone Acrolein Butyraldehyde Carbon dioxide Carbon monoxide Crotonaldehyde Formaldehyde Hydrocarbons, total, as carbon NOx PM, condensable PM, condensable PM, condensable PM, PM, PM, PM, PM,

condensable filterable filterable filterable filterable

Value

Unit

Measure

Material

Action

EF quality

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.10E 01 3.90E 02 3.30E 02 1.70E 02 6.70E+02 5.90E+00 1.10E 02 3.40E 01 3.40E+00

lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood wood wood

Produced Produced Produced Produced Produced Produced Produced Produced Produced

D E E E E D E D D

Uncontrolled Uncontrolled Multiple cyclones Wet electrostatic precipitator Electrified filter bed Uncontrolled Multiple cyclones Wet scrubber Wet electrostatic precipitator Electrified filter bed Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Incinerator Incinerator Uncontrolled Incinerator Uncontrolled

5.10E 01 1.10E+00 1.50E+00 3.60E 01

lb lb lb lb

Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood

Produced Produced Produced Produced

D E E E

7.50E 01 4.70E+00 3.30E+00 1.30E+00 6.60E 01

lb lb lb lb lb

Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood

Produced Produced Produced Produced Produced

E D E E D

4.20E 01 9.80E 03 4.40E+00 3.30E+02 7.20E 01 3.60E 02 6.80E 01 6.00E+02 1.30E 01 2.40E 03 2.20E 03 4.20E 01

lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood wood wood wood wood wood

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E D E E D E E E E E E E

Appendix

PM, filterable Propionaldehyde VOCs Direct natural gas-fired rotary Carbon dioxide dryer, hardwoods Carbon monoxide Formaldehyde NOx Indirect-heated rotary dryer, Carbon dioxide hardwoods Carbon monoxide Formaldehyde Formaldehyde Hydrocarbons, total, as carbon

Method of control

Carbon dioxide Carbon monoxide Carbon monoxide Formaldehyde Formaldehyde Hydrocarbons, total, as carbon Hydrocarbons, total, as carbon Methyl alcohol Methyl alcohol NOx NOx Phenol PM, filterable PM10, filterable VOCs VOCs Hot press, PF resin (dry)

Carbon monoxide Formaldehyde NOx PM, filterable

Incinerator

1.30E 02

lb

Tons

Oven-dried wood

Produced

E

Incinerator Incinerator Incinerator Uncontrolled Incinerator Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Miscellaneous control devices Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled

7.40E 2.40E 2.60E 5.10E 1.80E 2.80E 7.20E 6.20E 5.20E 3.50E 3.70E

01 02 03 01 02 02 01 02 03 03 03

lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons 1000 ft2 1000 ft2 1000 ft2

Oven-dried wood Oven-dried wood Oven-dried wood Oven-dried wood Oven-dried wood Oven-dried wood Oven-dried wood Oven-dried wood 3/8-inch-thick panel 3/8-inch-thick panel 3/8-inch-thick panel

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E E E D E E E E E

6.22E+01 9.50E 02 2.10E 01 4.40E 02 4.20E 03 1.40E 01

lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

panel panel panel panel panel panel

Produced Produced Produced Produced Produced Produced

D D E D E D

Miscellaneous control devices Uncontrolled Miscellaneous control devices Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled Uncontrolled Miscellaneous control devices Uncontrolled Uncontrolled Uncontrolled Uncontrolled

5.30E 02

lb

1000 ft2

3/8-inch-thick panel

Produced

E

5.00E 01 1.00E 01

lb lb

1000 ft2 1000 ft2

3/8-inch-thick panel 3/8-inch-thick panel

Produced Produced

E E

4.90E 3.50E 7.20E 1.20E 1.00E 2.10E 6.10E

02 01 02 01 01 01 02

lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2 ft2

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

panel panel panel panel panel panel panel

Produced Produced Produced Produced Produced Produced Produced

D E D D E E E

2.60E 1.40E 1.40E 1.10E

03 01 03 01

lb lb lb lb

1000 1000 1000 1000

ft2 ft2 ft2 ft2

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

panel panel panel panel

Produced Produced Produced Produced

E E E E

ft2 ft2 ft2 ft2 ft2 ft2

317

Continued

Appendix

Indirect-heated (heated zones) conveyor dryer, hardwoods Hot press, PF resin

Hydrocarbons, total, as carbon NOx PM, filterable Sulfur dioxide VOCs VOCs PM, condensable PM, filterable PM10, filterable Acetaldehyde Acetone Acetone

Pollutantb

Hot press, MDI resin

PM, condensable PM, filterable VOCs Acetaldehyde Acetone Acetone Acetone Carbon dioxide Carbon monoxide Carbon monoxide Formaldehyde Formaldehyde Formaldehyde Hydrocarbons, total, as carbon Hydrocarbons, total, as carbon Hydrocarbons, total, as carbon Methyl alcohol Methyl alcohol Methyl alcohol Methylene(B)4phenylisocyanate Methylene(B)4phenylisocyanate NOx NOx Phenol Phenol Phenol a-Pinene b-Pinene PM, condensable PM, condensable

Hot press, PF resin (surface layers)/MDI resin (core layers)

Method of control

Value

Unit

Measure

Action

EF quality

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Catalytic oxidizer Thermal oxidizer Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Catalytic oxidizer Thermal oxidizer Uncontrolled

2.00E 02 1.30E 01 2.00E 01 1.00E 02 1.10E 02 6.20E 03 7.10E 03 4.03E+01 1.00E 01 2.20E 01 5.60E 02 2.40E 02 3.80E 03 5.10E 01

lb lb lb lb lb lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000

panel panel panel panel panel panel panel panel panel panel panel panel panel panel

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D E D D E D C B D B E C B

Catalytic oxidizer

5.60E 02

lb

1000 ft2

3/8-inch-thick panel

Produced

E

2

3/8-inch-thick panel

Produced

C

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

panel panel panel panel

Produced Produced Produced Produced

D E D D

3/8-inch-thick panel

Produced

E

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D C E D D D B D

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

Thermal oxidizer

2.50E 02

lb

1000 ft

Uncontrolled Catalytic oxidizer Thermal oxidizer Uncontrolled

2.50E 4.00E 6.20E 1.10E

01 02 03 03

lb lb lb lb

1000 1000 1000 1000

Thermal oxidizer

9.70E 06

lb

1000 ft2

lb lb lb lb lb lb lb lb lb

2

Uncontrolled Thermal oxidizer Uncontrolled Catalytic oxidizer Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled Thermal oxidizer

4.10E 2.70E 1.50E 6.80E 8.70E 3.20E 1.20E 1.50E 9.30E

02 01 02 03 03 01 01 01 02

1000 1000 1000 1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2

ft ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

Material 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

panel panel panel panel panel panel panel panel panel

Appendix

Sourcea

318

Emission factors for wood manufacturing sectorsdcont’d

Sanderdust metering bin

Raw fuel bin

3.70E 4.90E 1.10E 3.70E 6.70E 8.60E 2.70E 1.80E 3.60E 1.30E

01 02 01 02 01 02 02 03 03 01

lb lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

panel panel panel panel panel panel panel panel panel panel

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

B D E E C E D U U U

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

6.30E 6.40E 1.90E 1.60E 9.50E

02 02 02 01 02

lb lb lb lb lb

1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

panel panel panel panel panel

Produced Produced Produced Produced Produced

U U U U U

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

7.30E 4.60E 1.30E 1.20E 1.50E 3.00E 5.00E

04 02 02 01 03 04 02

lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2 ft2

3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick 3/8-inch-thick

panel panel panel panel panel panel panel

Produced Produced Produced Produced Produced Produced Produced

U U U U U U U

Uncontrolled Uncontrolled Uncontrolled

1.50E 03 3.20E 02 6.00E 02

lb lb lb

1000 ft2 1000 ft2 1000 ft2

3/8-inch-thick panel 3/8-inch-thick panel 3/8-inch-thick panel

Produced Produced Produced

U U U

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.10E 1.80E 8.50E 2.60E 7.40E

01 02 02 01 01

lb lb lb lb lb

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

Wood Wood Wood Wood Wood

material material material material material

Produced Produced Produced Produced Produced

D D E D D

Uncontrolled Uncontrolled Uncontrolled

1.00E+00 8.30E 02 1.10E+00

lb lb lb

Oven-dried tons Oven-dried tons Oven-dried tons

Wood material Wood material Wood material

Produced Produced Produced

D D E

tons tons tons tons tons

Continued

319

Hardboard (HB) manufacture Acetaldehyde Tube dryer, direct woodAcetone fired, blowline blend, Carbon monoxide PF resin, hardwood Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol Phenol VOCs

Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled Catalytic oxidizer Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled

Appendix

Blender, PF resin/MDI resin

PM, filterable PM, filterable PM10, filterable Sulfur dioxide VOCs VOCs VOCs Acetone Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol a-Pinene b-Pinene VOCs Hydrocarbons, total, as carbon Methyl alcohol a-Pinene b-Pinene VOCs Acetone Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol a-Pinene VOCs

320

Emission factors for wood manufacturing sectorsdcont’d

Pollutantb

Method of control

Value

Unit

Measure

Material

Action

EF quality

Tube dryer, direct natural gas-fired, blowline blend, PF resin, hardwood

Acetaldehyde Acetone

Uncontrolled Uncontrolled

9.60E 03 9.50E 03

lb lb

Oven-dried tons Oven-dried tons

Wood material Wood material

Produced Produced

E E

Acrolein Benzene Carbon dioxide Carbon monoxide Ethylbenzene Formaldehyde Hexanal Hydrocarbons, total, as carbon Isomers of xylene Methyl alcohol Methyl chloride Methyl ethyl ketone NOx Phenol PM, condensable PM, filterable Propionaldehyde Styrene Toluene Trichlorofluoromethane VOCs Acetaldehyde Acetone Acrolein Benzene Carbon monoxide Formaldehyde Methyl alcohol Methyl ethyl ketone Methyl isobutyl ketone Phenol

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

4.10E 03 8.80E 05 3.84E+02 6.70E 02 1.30E 04 1.10E+00 5.20E 02 3.20E+00

lb lb lb lb lb lb lb lb

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

tons tons tons tons tons tons tons tons

Wood Wood Wood Wood Wood Wood Wood Wood

material material material material material material material material

Produced Produced Produced Produced Produced Produced Produced Produced

E E E E E E E E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

5.60E 05 1.40E+00 1.90E 05 8.30E 04 4.40E 01 5.60E 02 5.70E 01 1.90E+00 4.10E 02 2.70E 03 2.30E 04 2.00E 05

lb lb lb lb lb lb lb lb lb lb lb lb

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

tons tons tons tons tons tons tons tons tons tons tons tons

Wood Wood Wood Wood Wood Wood Wood Wood Wood Wood Wood Wood

material material material material material material material material material material material material

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E E E E E E E E E E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

5.00E+00 5.30E 02 2.10E 02 3.70E 02 2.10E 03 4.90E 01 5.90E 02 4.70E 02 1.30E 03 3.40E 03 1.90E 03

lb lb lb lb lb lb lb lb lb lb lb

Oven-dried tons 1000 ft2 1000 ft2 1000 ft2 1000 ft2 1000 ft2 1000 ft2 1000 ft2 1000 ft2 1000 ft2 1000 ft2

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E E E E E E E E E

Board dryer, direct natural gas-fired, softwood, linseed oil binder, heated zones

Wood material 1/2-inch-thick panel 1/2-inch-thick panel 1/2-inch-thick panel 1/2-inch-thick panel 1/2-inch-thick panel 1/2-inch-thick panel 1/2-inch-thick panel 1/2-inch-thick panel 1/2-inch-thick panel 1/2-inch-thick panel

Appendix

Sourcea

Tube dryer, second stage, indirect heated, hardwood

Humidification kiln, indirect heated

Methyl alcohol Methyl alcohol Methyl ethyl ketone Methyl isobutyl ketone Phenol Phenol Propionaldehyde VOCs Acetone Carbon monoxide

Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.50E 8.70E 7.50E 4.60E 1.90E 2.00E 1.00E 6.10E 3.10E 7.60E

02 04 04 03 03 03 01 01 02 02

lb lb lb lb lb lb lb lb lb lb

1000 ft2 1000 ft2 1000 ft2 1000 ft2 1000 ft2 1000 ft2 1000 ft2 1000 ft2 Oven-dried tons Oven-dried tons

1/8-inch-thick panel 1/8-inch-thick panel 1/8-inch-thick panel 1/8-inch-thick panel 1/8-inch-thick panel 1/8-inch-thick panel 1/8-inch-thick panel 1/8-inch-thick panel Wood material Wood material

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E E E E E E D E

Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol Phenol VOCs Acetaldehyde Acetone Acrolein Benzene Carbon monoxide Cresol 2-Cresol Ethyl chloride Ethylbenzene Formaldehyde Hexanal Hydrocarbons, total, as carbon Isomers of xylene Methyl chloride Methyl ethyl ketone NOx Phenol Propionaldehyde Toluene VOCs

Uncontrolled Uncontrolled

1.70E 02 2.30E 01

lb lb

Oven-dried tons Oven-dried tons

Wood material Wood material

Produced Produced

D D

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

4.20E 3.90E 2.70E 1.80E 3.80E 8.70E 6.20E 1.60E 3.30E 2.10E 1.40E 3.20E 1.00E 1.10E 6.20E

02 02 01 03 03 03 06 01 04 04 05 05 03 02 01

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

Oven-dried tons Oven-dried tons Oven-dried tons 1000 ft2 1000 ft2 1000 ft2 1000 ft2 1000 ft2 1000 ft2 1000 ft2 1000 ft2 1000 ft2 1000 ft2 1000 ft2 1000 ft2

Wood material Wood material Wood material 1/8-inch-thick panel 1/8-inch-thick panel 1/8-inch-thick panel 1/8-inch-thick panel 1/8-inch-thick panel 1/8-inch-thick panel 1/8-inch-thick panel 1/8-inch-thick panel 1/8-inch-thick panel 1/8-inch-thick panel 1/8-inch-thick panel 1/8-inch-thick panel

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D E E D E E E E E E E E E E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

4.20E 1.20E 1.40E 2.80E 5.70E 7.70E 3.40E 7.60E

05 04 03 03 04 03 05 01

lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000

1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick

Produced Produced Produced Produced Produced Produced Produced Produced

E E E E E E E E

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

panel panel panel panel panel panel panel panel

321

Continued

Appendix

Tempering oven, direct natural gas-fired, hardwood

322

Emission factors for wood manufacturing sectorsdcont’d

Pollutantb

Hot press, PF resin

Acetaldehyde Acetaldehyde Acetone Acetone Formaldehyde Formaldehyde Hydrocarbons, total, as carbon Hydrocarbons, total, as carbon Isomers of xylene Methyl alcohol Methyl alcohol Phenol PM, condensable PM, filterable PM10, filterable Toluene VOCs VOCs o-Xylene Acetaldehyde Acetone Acrolein Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol Methyl ethyl ketone Phenol Propionaldehyde VOCs

Hot press, linseed oil binder

Method of control

Value

Uncontrolled Venturi scrubber Uncontrolled Venturi scrubber Uncontrolled Venturi scrubber Uncontrolled

1.60E 3.30E 5.50E 3.90E 1.40E 3.40E 4.20E

Action

EF quality

panel panel panel panel panel panel panel

Produced Produced Produced Produced Produced Produced Produced

D E D E D E D

1/8-inch-thick panel

Produced

E

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick

panel panel panel panel panel panel panel panel panel panel panel panel panel panel panel panel

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D E D E E E D E E D E E E E E

ft2 ft2 ft2 ft2 ft2

1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick

panel panel panel panel panel

Produced Produced Produced Produced Produced

E E E E E

Unit

Measure

02 03 03 03 02 03 01

lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000

Venturi scrubber

4.30E 02

lb

1000 ft2

Uncontrolled Uncontrolled Venturi scrubber Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Venturi scrubber Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

5.30E 2.40E 1.50E 1.00E 1.20E 1.40E 8.60E 1.10E 5.20E 5.20E 3.60E 3.60E 1.50E 5.70E 1.80E 5.80E

03 01 01 02 01 01 02 03 01 02 03 02 02 03 02 01

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

9.30E 4.50E 3.90E 3.10E 7.10E

02 03 03 02 01

lb lb lb lb lb

1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2 ft2

Material 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick 1/8-inch-thick

Appendix

Sourcea

Pressurized digester/refiner, hardwood

Former, vacuum system, wet, PF resin

Fiberboard (FB) manufacture Board dryer, indirect heated, softwood, starch binder, heated zones

Board dryer, indirect heated, softwood, 6–12% asphalt binder, heated zones

Fabric filter Uncontrolled

3.00E 02 4.10E 03

lb lb

1000 ft2 Oven-dried tons

1/8-inch-thick panel Wood material

Produced Produced

E E

Uncontrolled Uncontrolled Uncontrolled

1.00E 03 5.00E 03 3.00E 02

lb lb lb

Oven-dried tons Oven-dried tons Oven-dried tons

Wood material Wood material Wood material

Produced Produced Produced

E E E

Acetone Acrolein Formaldehyde Acetaldehyde Acetone Formaldehyde Methyl alcohol Methyl ethyl ketone Methyl isobutyl ketone Phenol Propionaldehyde

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

4.20E 2.40E 4.50E 5.80E 3.20E 2.60E 5.40E 3.00E 2.30E 7.10E 2.10E

03 03 03 03 03 04 02 04 04 04 04

lb lb lb lb lb lb lb lb lb lb lb

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

Wood Wood Wood Wood Wood Wood Wood Wood Wood Wood Wood

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E D D D D D D D D

Acetaldehyde Acetone Acrolein Carbon monoxide Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol Phenol a-Pinene Propionaldehyde VOCs Acetaldehyde Acetone Acrolein Carbon monoxide Formaldehyde Hydrocarbons, total, as carbon

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

9.70E 3.80E 5.70E 9.20E 9.30E 6.30E

04 03 04 02 03 02

lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2

1/2-inch-thick 1/2-inch-thick 1/2-inch-thick 1/2-inch-thick 1/2-inch-thick 1/2-inch-thick

panel panel panel panel panel panel

Produced Produced Produced Produced Produced Produced

E E E E E E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.70E 1.20E 1.30E 6.90E 8.20E 2.90E 4.80E 1.20E 2.90E 1.30E 1.10E

02 03 02 04 02 03 03 03 02 02 01

lb lb lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

1/2-inch-thick 1/2-inch-thick 1/2-inch-thick 1/2-inch-thick 1/2-inch-thick 1/2-inch-thick 1/2-inch-thick 1/2-inch-thick 1/2-inch-thick 1/2-inch-thick 1/2-inch-thick

panel panel panel panel panel panel panel panel panel panel panel

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E E E E E E E E D

tons tons tons tons tons tons tons tons tons tons tons

material material material material material material material material material material material

Continued

323

PM, filterable Hydrocarbons, total, as carbon Methyl alcohol VOCs Acetaldehyde

Appendix

Sander Log chipper, hardwood

324

Emission factors for wood manufacturing sectorsdcont’d

Sourcea

Atmospheric refiner and dump chest, softwood

Washer, softwood

Former, vacuum system, wet, 6–12% asphalt

Pollutantb

Value

Unit

Measure

Material

Action

EF quality

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

2.60E 1.40E 1.40E 1.40E 2.70E 3.90E 3.00E 6.10E 7.90E

02 03 02 01 03 03 04 04 01

lb lb lb lb lb lb lb lb lb

1000 ft2 1000 ft2 1000 ft2 1000 ft2 Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

tons tons tons tons tons

1/2-inch-thick panel 1/2-inch-thick panel 1/2-inch-thick panel 1/2-inch-thick panel Wood material Wood material Wood material Wood material Wood material

Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E E E E E E E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

3.40E 1.70E 8.40E 2.10E 7.20E 9.90E 2.60E 2.90E 9.60E 1.50E 4.70E 2.60E 1.90E

03 02 03 04 01 02 04 04 01 02 03 03 01

lb lb lb lb lb lb lb lb lb lb lb lb lb

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

tons tons tons tons tons tons tons tons tons tons tons tons tons

Wood Wood Wood Wood Wood Wood Wood Wood Wood Wood Wood Wood Wood

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E E E E E E E E E E E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.30E 2.30E 7.50E 1.40E 3.60E 1.50E

01 01 03 02 03 01

lb lb lb lb lb lb

Oven-dried tons Oven-dried tons 1000 ft2 1000 ft2 1000 ft2 1000 ft2

Wood material Wood material 1/2-inch-thick panel 1/2-inch-thick panel 1/2-inch-thick panel 1/2-inch-thick panel

Produced Produced Produced Produced Produced Produced

E E E E E E

Uncontrolled Uncontrolled Uncontrolled

1.40E 02 2.30E 03 1.70E 01

lb lb lb

1000 ft2 1000 ft2 1000 ft2

1/2-inch-thick panel 1/2-inch-thick panel 1/2-inch-thick panel

Produced Produced Produced

E E E

material material material material material material material material material material material material material

Appendix

Methyl alcohol Phenol a-Pinene VOCs Acetaldehyde Acetone Acrolein Formaldehyde Hydrocarbons, total, as carbon Isopropylbenzene Limonene Methyl alcohol Methyl ethyl ketone a-Pinene b-Pinene Propionaldehyde Toluene VOCs Acetaldehyde Acetone Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol VOCs Acetaldehyde Acetone Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol Toluene VOCs

Method of control

1.30E 02

lb

1000 ft2

3/8-inch-thick veneer

Produced

E

Uncontrolled Uncontrolled

1.60E 02 2.10E 01

lb lb

1000 ft2 1000 ft2

3/8-inch-thick veneer 3/8-inch-thick veneer

Produced Produced

E E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.80E 01 2.60E 01 2.90E 01 1.10E+00 2.90E 01 9.20E+00

lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft3 ft3

3/8-inch-thick veneer 3/8-inch-thick veneer Product Product Product Product

Produced Produced Produced Produced Produced Produced

E E E D D D

Uncontrolled Uncontrolled Uncontrolled Uncontrolled

3.10E+00 2.40E 01 1.04E+01 8.90E 02

lb lb lb lb

1000 1000 1000 1000

ft3 ft3 ft3 linear ft

Product Product Product Product

Produced Produced Produced Produced

D E E E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.60E 1.10E 1.40E 1.80E 2.80E

02 01 04 04 03

lb lb lb lb lb

1000 1000 1000 1000 1000

linear linear linear linear linear

ft ft ft ft ft

Product Product Product Product Product

Produced Produced Produced Produced Produced

E E E E E

Uncontrolled Uncontrolled

6.30E 04 3.50E 03

lb lb

1000 linear ft 1000 linear ft

Product Product

Produced Produced

E E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

6.20E 03 9.20E+02 1.30E+00 9.60E 02 1.60E 01

lb lb lb lb lb

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

tons tons tons tons tons

Wood Wood Wood Wood Wood

material material material material material

Produced Produced Produced Produced Produced

E D D D D

Uncontrolled Electrified filter bed Electrified filter bed Uncontrolled Uncontrolled Electrified filter bed

4.70E 01 3.30E 01 4.30E 01 2.90E 01 2.30E+00 3.10E 01

lb lb lb lb lb lb

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

tons tons tons tons tons tons

Wood Wood Wood Wood Wood Wood

material material material material material material

Produced Produced Produced Produced Produced Produced

D D D E D D Continued

325

Uncontrolled

Appendix

Laminated veneer lumber (LVL) manufacture LVL, veneer, indirect heated, Hydrocarbons, hardwood, heated zones total, as carbon VOCs LVL, veneer, indirect heated, Hydrocarbons, hardwood, cooling section total, as carbon PM, filterable VOCs LVL, press, PF resin Acetaldehyde Acetone Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol Propionaldehyde VOCs LVL, I-beam saw Hydrocarbons, total, as carbon Methyl alcohol VOCs I-joist manufacture, I-joist, Acetone curing chamber Formaldehyde Hydrocarbons, total, as carbon Methyl alcohol VOCs Laminated strand lumber LSL, rotary, direct Acrolein wood-fired, hardwood Carbon dioxide Carbon monoxide Formaldehyde Hydrocarbons, total, as carbon NOx PM, condensable PM, filterable VOCs LSL, conveyor, indirect NOx heated, hardwood PM, filterable

326

Emission factors for wood manufacturing sectorsdcont’d

Value

Unit

Measure

Material

Action

EF quality

Uncontrolled Uncontrolled Uncontrolled

7.00E 01 2.90E 02 9.00E 02

lb lb lb

1000 ft3 1000 ft3 1000 ft3

Product Product Product

Produced Produced Produced

E E D

Uncontrolled Uncontrolled Fabric filter Fabric filter Fabric filter Fabric filter

2.70E 01 4.40E 01 1.10E+00 5.20E 02 2.30E 01 4.10E 01

lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000

ft3 ft3 ft3 ft3 ft3 ft3

Product Product Product Product Product Product

Produced Produced Produced Produced Produced Produced

E E E E D D

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

9.90E 1.40E 6.20E 1.10E 2.80E 2.20E

05 04 03 01 04 04

lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2

Particleboard Particleboard Particleboard Particleboard Particleboard Particleboard

Processed Processed Processed Processed Processed Processed

E E E E E E

Miscellaneous wood working operations Wood-waste storage bin vent PM, filterable PM10, filterable Wood-waste storage PM, filterable bin load-out PM10, filterable

Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.00E+00 5.80E 01 2.00E+00 1.20E+00

lb lb lb lb

Tons Tons Tons Tons

Wood Wood Wood Wood

Processed Processed Processed Processed

C C C C

Medium-density fiberboard (MDF) manufacture Batch hot press, UF resin Methyl ethyl ketone

Uncontrolled

5.90E 04

lb

1000 ft2

Produced

E

Uncontrolled

3.00E 02

lb

1000 ft2

Produced

E

2

3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard Oven-dried wood Oven-dried wood Oven-dried wood Oven-dried wood Oven-dried wood

Produced

E

Produced Produced Produced Produced Produced

D D D D E

Pollutantb

LSL, press, MDI resin

Carbon monoxide Formaldehyde Methylene(B)4phenylisocyanate PM, condensable PM, filterable PM, condensable PM10, filterable PM, condensable PM10, filterable Acetaldehyde Butyraldehyde Formaldehyde Hexanal Methyl ethyl ketone 1,1,1-Trichloroethane

LSL, sander LSL, saw Furniture manufacture Veneer hot press, UF resin

NOx

Direct wood-fired tube dryer, unspecified pines

PM, condensable

Uncontrolled

2.60E 01

lb

1000 ft

Carbon monoxide PM, condensable PM, filterable PM10, filterable VOCs

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

4.00E+00 5.90E 01 1.00E+01 1.60E+00 6.60E+00

lb lb lb lb lb

Tons Tons Tons Tons Tons

Waste Waste Waste Waste

Appendix

Method of control

Sourcea

Indirect-heated tube dryer, unspecified pines Indirect-heated tube dryer, hardwoods Indirect-heated tube dryer, 50% softwood, 50% hardwood

Carbon monoxide Formaldehyde VOCs PM, filterable

Uncontrolled Uncontrolled Uncontrolled Uncontrolled

4.00E+00 8.60E 01 6.50E+00 1.40E+00

lb lb lb lb

Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood

Produced Produced Produced Produced

D E D E

Acetaldehyde Formaldehyde VOCs Acetaldehyde Acetone Acetophenone Acrolein Benzaldehyde Butylbenzylphthalate Butyraldehyde Crotonaldehyde p-Cymene Dibutyl phthalate Dichloromethane 2,5-Dimethylbenzaldehyde Dioctyl phthalate Formaldehyde Hexanal Isovaleraldehyde Methyl chloride Methyl ethyl ketone n-Hexane Naphthalene Phenol a-Pinene PM, condensable PM, filterable PM10, filterable Propionaldehyde a-Terpineol o-Tolualdehyde

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.30E 02 2.00E 01 4.70E+00 1.30E 02 2.50E 03 2.40E 04 2.20E 03 2.60E 03 2.40E 04 2.80E 03 1.90E 03 1.90E 04 1.80E 04 2.90E 03 3.80E 04

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E D E E E E E E E E E E E E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

2.70E 04 1.40E+00 2.60E 03 1.90E 03 1.50E 03 6.30E 03 1.40E 03 6.60E 04 2.00E 04 6.20E 03 7.30E 01 1.50E+00 2.80E 01 1.10E 03 2.20E 03 7.40E 04

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E E E E E E E E E E E E E E

327

Continued

Appendix

Direct wood-fired tube dryer, hardwoods

Sourcea

Continuous hot press, UF resin

Method of control

Value

Unit

Measure

Material

Action

EF quality

p-Tolualdehyde Trichlorofluoromethane 2,2,4-Trimethylpentane Valeraldehyde VOCs Carbon monoxide

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Thermal oxidizer

3.60E 03 1.40E 03 6.20E 04 2.10E 03 2.20E+00 8.50E 02

lb lb lb lb lb lb

Tons Tons Tons Tons Tons 1000 ft2

Produced Produced Produced Produced Produced Produced

E E E E E E

Formaldehyde

Uncontrolled

1.10E+00

lb

1000 ft2

Produced

E

2

Oven-dried wood Oven-dried wood Oven-dried wood Oven-dried wood Oven-dried wood 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Formaldehyde

Thermal oxidizer

9.10E 03

lb

1000 ft

NOx

Thermal oxidizer

5.10E 01

lb

1000 ft2

PM, condensable

Uncontrolled

1.40E 01

lb

1000 ft2

lb

1000 ft

2

2

Thermal oxidizer

1.60E 02

PM, filterable

Uncontrolled

1.70E 01

lb

1000 ft

PM, filterable

Thermal oxidizer

4.00E 02

lb

1000 ft2

VOCs

Uncontrolled

1.40E+00

lb

1000 ft2

lb

1000 ft

2

2

VOCs

Thermal oxidizer

3.20E 02

Acetaldehyde

Uncontrolled

5.10E 03

lb

1000 ft

Acetone

Uncontrolled

3.10E 03

lb

1000 ft2

Acrolein

Uncontrolled

1.20E 03

lb

1000 ft2

lb

1000 ft

2

1000 ft

2

Benzaldehyde Butyraldehyde

Uncontrolled Uncontrolled

5.50E 04 2.40E 03

lb

Appendix

Pollutantb

PM, condensable

Batch hot press, UF resin

328

Emission factors for wood manufacturing sectorsdcont’d

3.40E 02

lb

1000 ft2 2

Crotonaldehyde

Uncontrolled

1.10E 03

lb

1000 ft

2,5-Dimethylbenzaldehyde Formaldehyde

Uncontrolled

2.50E 03

lb

1000 ft2

Uncontrolled

3.00E 01

lb

1000 ft2

lb

1000 ft

2

2

Hexanal

Uncontrolled

2.90E 03

Isovaleraldehyde

Uncontrolled

1.40E 03

lb

1000 ft

PM, filterable

Uncontrolled

1.80E 01

lb

1000 ft2

PM10, filterable

Uncontrolled

7.50E 02

lb

1000 ft2

lb

1000 ft

2

2

Propionaldehyde

Uncontrolled

5.40E 04

o-Tolualdehyde

Uncontrolled

7.00E 04

lb

1000 ft

p-Tolualdehyde

Uncontrolled

1.00E 03

lb

1000 ft2

Valeraldehyde

Uncontrolled

2.40E 03

lb

1000 ft2

lb

1000 ft

2

2

VOCs MDF board cooler, UF resin

Uncontrolled

Uncontrolled

6.90E 01

Acetaldehyde

Uncontrolled

1.00E 03

lb

1000 ft

Acetone

Uncontrolled

2.10E 03

lb

1000 ft2

Acrolein

Uncontrolled

2.20E 04

lb

1000 ft2

lb

1000 ft

2

1000 ft

2

1000 ft

2

Benzaldehyde Butyraldehyde Crotonaldehyde

Uncontrolled Uncontrolled Uncontrolled

9.90E 05 1.40E 03 2.60E 04

lb lb

3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard

Produced

E

Produced

E

Produced

E

Produced

D

Produced

E

Produced

E

Produced

D

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

D

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

329

Continued

Appendix

Carbon monoxide

Sourcea

Pollutantb

Unit

Measure

Material

Action

EF quality

3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard 3/4-inch medium-density fiberboard

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Produced

E

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E E E E E E E E D C

1.90E 04

lb

1000 ft2

Uncontrolled

1.10E 01

lb

1000 ft2

Hexanal

Uncontrolled

6.50E 04

lb

1000 ft2

lb

1000 ft

2

2

Uncontrolled

2.50E 04

Methyl ethyl ketone

Uncontrolled

1.10E 04

lb

1000 ft

PM, filterable

Uncontrolled

5.40E 02

lb

1000 ft2

PM10, filterable

Uncontrolled

3.80E 03

lb

1000 ft2

lb

1000 ft

2

1000 ft

2

2

p-Tolualdehyde

Uncontrolled Uncontrolled

6.50E 05 1.70E 04

lb

Valeraldehyde

Uncontrolled

4.80E 04

lb

1000 ft

VOCs

Uncontrolled

2.00E 01

lb

1000 ft2

Acetaldehyde Acetone Acetophenone Acrolein Acrylonitrile Benzaldehyde Benzene Biphenyl Butylbenzylphthalate Butyraldehyde Carbon dioxide Carbon monoxide

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.00E 02 7.90E 03 6.40E 05 3.30E 03 8.90E 05 2.60E 03 2.20E 04 3.90E 05 1.40E 05 3.10E 03 5.70E+02 1.60E+00

lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

wood wood wood wood wood wood wood wood wood wood wood wood

Appendix

Value

Uncontrolled

o-Tolualdehyde

Particleboard manufacture Direct wood-fired rotary dryer, unspecified pines, <730 F inlet air

Method of control

2,5-Dimethylbenzaldehyde Formaldehyde

Isovaleraldehyde

330

Emission factors for wood manufacturing sectorsdcont’d

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.80E 1.20E 6.20E 2.30E 2.40E

05 05 03 05 05

lb lb lb lb lb

Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood

Produced Produced Produced Produced Produced

E E E E E

Uncontrolled Uncontrolled

6.60E 04 3.30E 05

lb lb

Tons Tons

Oven-dried wood Oven-dried wood

Produced Produced

E E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

3.20E 3.80E 3.00E 1.60E 6.00E 6.90E 5.20E 2.80E 1.10E 1.30E 8.10E 1.40E 3.30E

04 06 02 02 05 05 04 05 04 03 05 05 05

lb lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood wood wood wood wood wood wood

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E E E E E E E E E E E

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Fabric filter Electrified filter bed Uncontrolled Multiple cyclones Fabric filter Electrified filter bed Uncontrolled Electrified filter bed Uncontrolled

2.60E 05 1.70E 05 1.10E+00 4.60E 01 1.60E 01 3.00E 01 9.70E 01 1.30E+00 3.90E+00 2.50E+00 1.40E+00 8.50E 01 6.90E 01 6.40E 01 1.20E 04

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E B E E D D D D E E D D E E

331

Continued

Appendix

Carbon sulfide Carbon tetrachloride p-Cymene Dibutyl phthalate 1,4-Dichlorobutene, trans Dichloromethane 2,5-Dimethylbenzaldehyde Dioctyl phthalate Ethylbenzene Formaldehyde Hexanal Hydroquinone Isopropylbenzene Isovaleraldehyde Methyl bromide Methyl chloride Methyl ethyl ketone Methyl isobutyl ketone Methyl sulfide 4,4-Methylene dianiline n-Hexane Nitrobenzene NOx a-Pinene b-Pinene PM, condensable PM, condensable PM, condensable PM, filterable PM, filterable PM, filterable PM, filterable PM10, filterable PM10, filterable Styrene

Sourcea

Direct wood-fired rotary dryer, unspecified pines, >900 F inlet air

Pollutantb

Method of control

Value

Unit

Measure

Material

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

2.00E 03 6.60E 02 3.50E 04 1.70E 03 1.20E 05 9.00E 05 4.50E 03 2.90E 05 9.50E 01 5.50E 05 1.40E 05 5.50E 05 7.20E 02 1.60E 01 2.30E 02 1.20E 01 2.90E 02 3.00E 02 5.70E+02 1.60E+00 1.00E 04 1.00E 02 1.10E 02 2.20E 03 5.30E 03

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

1.70E 01 2.20E 02 2.00E 03 1.80E 02 9.20E 03 1.10E+00 1.90E+00 8.20E 01 3.00E 01

lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

Action

EF quality

wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E E E E E E D E E E E E E E E E D C E E E E E

wood wood wood wood wood wood wood wood wood

Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E E E B E E D

Appendix

Sulfur dioxide a-Terpineol m-Tolualdehyde Toluene 1,1,1-Trichloroethane 1,2,4-Trimethylbenzene Valeraldehyde Vinyl acetate VOCs m-Xylene o-Xylene p-Xylene Acetaldehyde Acetone Acrolein Benzaldehyde Butyraldehyde Butyraldehyde Carbon dioxide Carbon monoxide Chloroform Crotonaldehyde p-Cymene Dichloromethane 2,5-Dimethylbenzaldehyde Formaldehyde Hexanal Isopropylbenzene Isovaleraldehyde Methyl ethyl ketone NOx a-Pinene b-Pinene PM, condensable

332

Emission factors for wood manufacturing sectorsdcont’d

Direct wood-fired rotary dryer, hardwoods

PM, condensable PM, condensable

Fabric filter Electrified filter bed Uncontrolled Multiple cyclones Fabric filter Electrified filter bed Uncontrolled Electrified filter bed Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Packed-gas absorption column Multiple cyclones Electrified filter bed

9.70E 01 1.30E+00 3.90E+00 2.50E+00 1.40E+00 8.50E 01 6.90E 01 6.40E 01 1.10E 02 3.60E 04 2.00E 03 1.70E 01 1.10E 02 2.60E 02 2.10E 02 1.40E 02 8.20E+00 3.80E 03 4.50E 04 3.80E 03 5.70E+02 1.60E+00 2.10E 02 1.10E+00 4.30E 01 8.00E+00 9.00E 01 2.00E 03 1.10E+00 5.70E+02 1.60E+00 1.10E+00 1.30E 01 2.40E 02

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D D E E D D E E E E E E E E E D E E E D C E B D D D E D D C B E D

1.30E 01 8.70E 02

lb lb

Tons Tons

Oven-dried wood Oven-dried wood

Produced Produced

D D

333

Continued

Appendix

Direct wood-fired rotary dryer, southern yellow pine

PM, condensable PM, condensable PM, filterable PM, filterable PM, filterable PM, filterable PM10, filterable PM10, filterable Propionaldehyde Styrene Sulfur dioxide a-Terpineol o-Tolualdehyde p-Tolualdehyde Toluene Valeraldehyde VOCs m-Xylene o-Xylene p-Xylene Carbon dioxide Carbon monoxide Formaldehyde NOx PM, condensable PM, filterable PM10, filterable Sulfur dioxide VOCs Carbon dioxide Carbon monoxide NOx PM, condensable PM, condensable

Sourcea

Pollutantb PM, filterable PM, filterable

Direct natural gas-fired rotary dryer, unspecified pines

Direct wood-fired rotary final dryer, unspecified pines Direct wood-fired rotary predryer, Douglas fir

PM, filterable PM, filterable Sulfur dioxide VOCs Carbon monoxide Methane NOx PM, condensable PM, condensable PM, filterable PM, filterable PM, filterable VOCs Carbon monoxide

Carbon monoxide NOx PM, condensable PM, filterable PM, filterable

Batch hot press, UF resin

Uncontrolled Packed-gas absorption column Multiple cyclones Electrified filter bed Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Incinerator Electrified filter bed Uncontrolled Incinerator Electrified filter bed Uncontrolled Uncontrolled

Uncontrolled Uncontrolled Wet electrostatic precipitator Multiple cyclones Wet electrostatic precipitator Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

Value

Unit

Measure

Material

Action

EF quality

2.50E+00 9.30E 01

lb lb

Tons Tons

Oven-dried wood Oven-dried wood

Produced Produced

D D

2.10E+00 1.90E 01 2.00E 03 3.50E 01 1.20E 01 2.70E 01 3.10E 02 1.50E 02 6.40E 02 1.30E+00 2.20E 01 1.40E 01 9.00E 01 7.50E 01

lb lb lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood wood wood wood wood wood wood wood

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D E D D E D E E E E E D D

9.40E 01 2.10E+00 1.50E 01

lb lb lb

Tons Tons Tons

Oven-dried wood Oven-dried wood Oven-dried wood

Produced Produced Produced

D D D

7.40E 01 1.10E 01

lb lb

Tons Tons

Oven-dried wood Oven-dried wood

Produced Produced

D D

1.40E 1.30E 1.90E 1.80E 1.80E 9.00E 5.00E 3.20E

lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000

3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch

Produced Produced Produced Produced Produced Produced Produced Produced

E E E E E D E E

02 02 03 03 03 02 04 04

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

particleboard particleboard particleboard particleboard particleboard particleboard particleboard particleboard

Appendix

Acetaldehyde Acetone Acrolein Benzaldehyde Butyraldehyde Carbon monoxide Crotonaldehyde 2,5-Dimethylbenzaldehyde

Method of control

334

Emission factors for wood manufacturing sectorsdcont’d

2.60E 4.50E 1.10E 1.40E 5.40E 1.10E 6.10E 3.00E 1.60E 7.20E 4.70E 3.90E 9.40E 1.30E 2.00E

01 02 03 03 04 04 02 02 02 05 04 03 01 03 03

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch

particleboard particleboard particleboard particleboard particleboard particleboard particleboard particleboard particleboard particleboard particleboard particleboard particleboard particleboard particleboard

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E E E E D E D E E E D E E

Acrolein Benzaldehyde Butyraldehyde Crotonaldehyde Formaldehyde Hexanal Isovaleraldehyde Methyl ethyl ketone PM, condensable PM, filterable PM10, filterable Valeraldehyde VOCs

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

3.60E 4.20E 6.00E 2.90E 2.70E 1.10E 4.00E 1.10E 9.20E 1.40E 3.40E 1.50E 2.70E

04 04 04 04 02 03 04 04 03 02 03 03 01

lb lb lb lb lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch 3/4-inch

particleboard particleboard particleboard particleboard particleboard particleboard particleboard particleboard particleboard particleboard particleboard particleboard particleboard

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E E D E E E E E E E D

Thermal oxidizer

2.60E 01

lb

1000 ft2

Produced

D

lb

1000 ft

2

Produced

E

2

Produced

E

Produced

D

Produced

D

Oriented strandboard (OSB) manufacture Hot press, MDI resin Carbon monoxide Formaldehyde

Uncontrolled

6.40E 02

Methylene(B)4phenylisocyanate NOx

Uncontrolled

1.70E 03

lb

1000 ft

Uncontrolled

3.80E 02

lb

1000 ft2

NOx

Thermal oxidizer

2.80E 01

lb

1000 ft2

3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board

Continued

335

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

Appendix

Particleboard board cooler, UF resin

Formaldehyde Hexanal Isovaleraldehyde Methyl ethyl ketone a-Pinene b-Pinene PM, condensable PM, filterable PM10, filterable Propionaldehyde Toluene Valeraldehyde VOCs Acetaldehyde Acetone

336

Emission factors for wood manufacturing sectorsdcont’d

Sourcea

Pollutantb

Direct wood-fired rotary dryer, unspecified pines

Carbon dioxide Carbon dioxide Carbon monoxide Carbon monoxide Chromium Formaldehyde Formaldehyde NOx NOx PM, condensable PM, condensable PM, condensable PM, condensable PM, PM, PM, PM, PM,

Direct wood-fired rotary dryer, aspen

condensable filterable filterable filterable filterable

Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Multiple cyclones Thermal oxidizer Wet electrostatic precipitator Electrified filter bed Uncontrolled Multiple cyclones Thermal oxidizer Wet electrostatic precipitator Electrified filter bed Multiple cyclones Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Thermal oxidizer Electrified filter bed

Action

EF quality

wood wood wood wood wood wood wood wood wood wood wood wood wood

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

B B B C E D E B C D B D E

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood

Produced Produced Produced Produced Produced

D D C D E

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood wood wood wood wood wood wood

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D C E C D B B B C E B C D

Value

Unit

Measure

Material

6.00E+02 7.60E+02 5.80E+00 2.10E+00 6.30E 05 6.70E 02 3.40E 02 6.50E 01 6.00E 01 1.90E+00 4.10E 01 1.20E 01 8.30E 01

lb lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

4.90E 01 3.90E+00 2.10E+00 1.70E 01 2.00E 01

lb lb lb lb lb

Tons Tons Tons Tons Tons

6.10E 01 2.50E+00 1.40E 02 8.60E+00 3.30E 01 6.00E+02 7.60E+02 5.80E+00 2.10E+00 1.10E 01 6.50E 01 6.00E 01 3.50E 01

lb lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Appendix

PM, filterable PM10, filterable Sulfur dioxide VOCs VOCs Carbon dioxide Carbon dioxide Carbon monoxide Carbon monoxide Formaldehyde NOx NOx PM, condensable

Method of control

1.10E+00 1.20E+00 1.40E 02 2.20E+00 1.60E 03 3.00E 06 6.00E+02 7.60E+02 5.80E+00 2.10E+00 8.40E 02 1.70E 02 6.50E 01 6.00E 01 5.00E 03 1.90E+00 5.00E 01 1.20E 01 3.00E 01

lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood wood

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

D D E D E E B B B C D E B C E E D E D

4.00E 01 6.90E+00 3.60E 02 2.00E 01

lb lb lb lb

Tons Tons Tons Tons

Oven-dried Oven-dried Oven-dried Oven-dried

wood wood wood wood

Produced Produced Produced Produced

C D E D

PM, filterable PM10, filterable Sulfur dioxide VOCs VOCs Carbon dioxide Carbon monoxide Formaldehyde NOx Carbon dioxide

Electrified filter bed Electrified filter bed Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Multiple cyclones Thermal oxidizer Wet electrostatic precipitator Electrified filter bed Multiple cyclones Thermal oxidizer Wet electrostatic precipitator Electrified filter bed Electrified filter bed Thermal oxidizer Uncontrolled Thermal oxidizer Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

9.20E 01 1.00E+00 1.40E 02 1.60E+00 3.60E 02 3.30E+02 7.20E 01 3.60E 02 6.80E 01 1.20E+01

lb lb lb lb lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons Tons Tons Tons 1000 ft2

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

C D E B E E D E E B

Carbon dioxide

Thermal oxidizer

4.20E+01

lb

1000 ft2

Oven-dried wood Oven-dried wood Oven-dried wood Oven-dried wood Oven-dried wood Oven-dried wood Oven-dried wood Oven-dried wood Oven-dried wood 3/8-inch oriented strand board 3/8-inch oriented strand board

Produced

C

PM, PM, PM, PM,

Direct natural gas-fired rotary dryer, hardwoods

Hot press, PF resin

condensable filterable filterable filterable

337

Continued

Appendix

Direct wood-fired rotary dryer, hardwoods

PM, filterable PM10, filterable Sulfur dioxide VOCs Benzene Benzo[a]pyrene Carbon dioxide Carbon dioxide Carbon monoxide Carbon monoxide Formaldehyde Formaldehyde NOx NOx Phenol PM, condensable PM, condensable PM, condensable PM, condensable

338

Emission factors for wood manufacturing sectorsdcont’d

Sourcea

Method of control

Value

Unit

Measure

Material

Action

EF quality

Carbon monoxide

Uncontrolled

1.10E 01

lb

1000 ft2

Produced

B

Carbon monoxide

Thermal oxidizer

2.60E 01

lb

1000 ft2

Produced

D

Formaldehyde

Uncontrolled

4.30E 02

lb

1000 ft2

Produced

E

lb

1000 ft

2

Produced

E

2

3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board

Produced

D

Produced

D

Produced

E

Produced

D

Produced

D

Produced

E

Produced

E

Produced

D

Produced

B

Produced

C

Produced

B

Produced

D

Produced

D

Naphthalene

3.00E 03

NOx

Uncontrolled

3.80E 02

lb

1000 ft

NOx

Thermal oxidizer

2.80E 01

lb

1000 ft2

Phenol

Uncontrolled

5.30E 02

lb

1000 ft2

lb

1000 ft

2

2

PM, condensable

Uncontrolled

2.50E 01

PM, filterable

Uncontrolled

1.20E 01

lb

1000 ft

PM10, filterable

Uncontrolled

1.00E 01

lb

1000 ft2

Sulfur dioxide

Uncontrolled

3.70E 02

lb

1000 ft2

lb

1000 ft

2

1000 ft

2

2

VOCs Hot press, MDI resin

Uncontrolled

Carbon dioxide

Uncontrolled Uncontrolled

5.20E 01 1.20E+01

lb

Carbon dioxide

Thermal oxidizer

4.20E+01

lb

1000 ft

Carbon monoxide

Uncontrolled

1.10E 01

lb

1000 ft2

PM, condensable

Uncontrolled

4.60E 02

lb

1000 ft2

lb

2

PM, filterable

Uncontrolled

1.60E 01

1000 ft

Appendix

Pollutantb

Uncontrolled

3.70E 02

lb

1000 ft2

VOCs

Uncontrolled

4.50E 01

lb

1000 ft2

lb

1000 ft

2

2

Carbon dioxide

Uncontrolled

1.20E+01

Carbon dioxide

Thermal oxidizer

4.20E+01

lb

1000 ft

Carbon monoxide

Uncontrolled

1.10E 01

lb

1000 ft2

Carbon monoxide

Thermal oxidizer

2.60E 01

lb

1000 ft2

lb

1000 ft

2

1000 ft

2

2

Formaldehyde Formaldehyde Methylene(B)4phenylisocyanate Methylene(B)4phenylisocyanate NOx NOx

Uncontrolled Thermal oxidizer

6.30E 02 4.30E 03

lb

Uncontrolled

2.10E 03

lb

1000 ft

Thermal oxidizer

7.80E 05

lb

1000 ft2

Uncontrolled

3.80E 02

lb

1000 ft2

lb

1000 ft

2

2

Thermal oxidizer

2.80E 01

Phenol

Uncontrolled

1.90E 02

lb

1000 ft

Phenol

Thermal oxidizer

2.60E 03

lb

1000 ft2

PM, condensable

Uncontrolled

1.40E 01

lb

1000 ft2

lb

1000 ft

2

2

PM, condensable

Thermal oxidizer

8.20E 02

PM, filterable

Uncontrolled

3.70E 01

lb

1000 ft

PM, filterable

Thermal oxidizer

4.90E 02

lb

1000 ft2

PM10, filterable

Uncontrolled

1.10E 01

lb

1000 ft2

3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board

Produced

E

Produced

D

Produced

B

Produced

C

Produced

B

Produced

D

Produced

D

Produced

E

Produced

D

Produced

E

Produced

D

Produced

D

Produced

D

Produced

E

Produced

B

Produced

D

Produced

B

Produced

D

Produced

E

339

Continued

Appendix

Hot press, PF resin (surface layers)/MDI resin (core layers)

Sulfur dioxide

Sourcea

Plywood operations Particleboard drying (see 3-07-006 for more detailed particleboard SCCs) Waferboard dryer (see 3-07-010 for more detailed OSB SCCs)

Hardboard, Hardboard, Hardboard, Hardboard,

core dryer predryer pressing bake oven

Pollutantb

Method of control

Value

Unit

Measure

Material

Action

EF quality

Sulfur dioxide

Uncontrolled

3.70E 02

lb

1000 ft2

Produced

E

VOCs

Uncontrolled

5.60E 01

lb

1000 ft2

Produced

B

VOCs

Thermal oxidizer

4.00E 02

lb

1000 ft2

3/8-inch oriented strand board 3/8-inch oriented strand board 3/8-inch oriented strand board

Produced

D

Formaldehyde PM, filterable PM10, filterable

Uncontrolled Uncontrolled Uncontrolled

4.35E 01 6.00E 01 3.50E 01

lb lb lb

Tons Tons Tons

Dry product Material Material

Produced Processed Processed

U U U

Formaldehyde

Uncontrolled

lb

Tons

Dry product

Produced

U

Formaldehyde NOx Phenol SOx VOCs NOx NOx Formaldehyde NOx VOCs VOCs

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

4.000E 03– 1.900E0 6.80E 01 1.14E+01 9.20E 03 1.71E+00 4.09E+01 3.00E 01 7.00E 02 2.80E 01 1.00E 01 3.00E 03 4.50E 01

lb lb lb lb lb lb lb lb lb lb lb

Tons 1000 lb Tons 1000 lb 1000 lb Tons Tons Tons Tons Tons 10,000 ft2

Dry product Wafers/chips Waferboard Wafers/chips Wafers/chips Dry product Dry product Dry product Product Product 3/8-inch plywood

Produced Dried Produced Dried Dried Produced Produced Produced Produced Produced Produced

U U U U U U U U U U B

VOCs VOCs

Uncontrolled Uncontrolled

7.53E+00 1.30E+00

lb lb

10,000 ft2 10,000 ft2

3/8-inch plywood 3/8-inch plywood

Produced Produced

B B

VOCs VOCs

Uncontrolled Uncontrolled

1.90E 01 2.94E+00

lb lb

10,000 ft2 10,000 ft2

3/8-inch plywood 3/8-inch plywood

Produced Produced

B B

Carbon monoxide NOx Sulfur dioxide

Uncontrolled Uncontrolled Uncontrolled

5.10E+00 2.40E 01 5.80E 02

lb lb lb

1000 ft2 1000 ft2 1000 ft2

3/8-inch plywood 3/8-inch plywood 3/8-inch plywood

Produced Produced Produced

D D D

Appendix

Fir, sapwood, steam-fired dryer Fir, sapwood, gas-fired dryer Fir, heartwood, plywood veneer dryer Larch plywood, veneer dryer Southern pine plywood, veneer dryer Direct wood-fired dryer, nonspecified pine species veneer

340

Emission factors for wood manufacturing sectorsdcont’d

Direct wood-fired dryer, nonspecified fir species veneer

Direct wood-fired dryer, Douglas fir veneer

VOCs Carbon monoxide NOx Sulfur dioxide VOCs Carbon monoxide NOx Sulfur dioxide VOCs PM, condensable PM, filterable VOCs

Direct natural gas-fired dryer, nonspecified pine species veneer

Indirect-heated dryer, nonspecified fir species veneer Indirect-heated dryer, Douglas fir veneer

Carbon monoxide NOx PM, condensable PM, filterable VOCs PM, condensable PM, filterable VOCs PM, condensable PM, filterable PM, condensable PM, condensable PM, filterable PM, filterable

Indirect-heated dryer, poplar veneer

VOCs Formaldehyde VOCs

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Ionizing wet scrubber Wet electrostatic precipitator Wet electrostatic precipitator Wet electrostatic precipitator Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Wet electrostatic precipitator Wet electrostatic precipitator Uncontrolled Wet electrostatic precipitator Uncontrolled Wet electrostatic precipitator Uncontrolled Uncontrolled Uncontrolled

3.30E+00 5.10E+00 2.40E 01 5.80E 02 7.00E 01 5.10E+00 2.40E 01 5.80E 02 6.10E 01

lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000

4.50E 02

lb

2.60E 01 5.00E 01

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

plywood plywood plywood plywood plywood plywood plywood plywood plywood

Produced Produced Produced Produced Produced Produced Produced Produced Produced

E D D D E D D D E

1000 ft2

3/8-inch plywood

Produced

D

lb

1000 ft2

3/8-inch plywood

Produced

D

lb

1000 ft2

3/8-inch plywood

Produced

D

5.70E 01 1.20E 02 4.20E 01 7.90E 02 2.10E+00 1.00E+00 3.50E 01 2.70E+00 6.50E 02

lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000

2

3/8-inch 3/8-inch 3/8-inch 3/8-inch 3/8-inch 3/8-inch 3/8-inch 3/8-inch 3/8-inch

plywood plywood plywood plywood plywood plywood plywood plywood plywood

Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E E E D D D E

3.40E 02

lb

1000 ft2

3/8-inch plywood

Produced

E

8.20E 01 1.10E 01

lb lb

1000 ft2 1000 ft2

3/8-inch plywood 3/8-inch plywood

Produced Produced

D E

7.00E 02 4.00E 02

lb lb

1000 ft2 1000 ft2

3/8-inch plywood 3/8-inch plywood

Produced Produced

D E

1.30E+00 2.30E 03 3.30E 02

lb lb lb

1000 ft2 1000 ft2 1000 ft2

3/8-inch plywood 3/8-inch plywood 3/8-inch plywood

Produced Produced Produced

D E E

ft ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

3/8-inch 3/8-inch 3/8-inch 3/8-inch 3/8-inch 3/8-inch 3/8-inch 3/8-inch 3/8-inch

341

Continued

Appendix

Direct wood-fired dryer, hemlock veneer

342

Emission factors for wood manufacturing sectorsdcont’d

Sourcea

Pollutantb

Method of control

Value

Radiofrequency heated dryer, nonspecified pine species Plywood press, PF resin

PM, condensable PM, filterable VOCs PM, condensable PM, filterable VOCs Formaldehyde Formaldehyde VOCs VOCs

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Wet scrubber Uncontrolled Wet scrubber

6.00E 5.00E 2.20E 8.30E 1.20E 3.30E 4.20E 2.50E 2.10E 1.80E

PM, filterable PM10, filterable PM, filterable PM10, filterable PM, filterable PM10, filterable

Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled Uncontrolled

Plywood press, UF resin

Sawmill operations Log debarking Log sawing Sawdust pile handling

Unit

Measure

Material

03 03 01 02 01 01 03 03 02 02

lb lb lb lb lb lb lb lb lb lb

1000 1000 1000 1000 1000 1000 1000 1000 1000 1000

ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2 ft2

3/8-inch 3/8-inch 3/8-inch 3/8-inch 3/8-inch 3/8-inch 3/8-inch 3/8-inch 3/8-inch 3/8-inch

2.00E 02 1.10E 02 3.50E 01 2.00E 01 1.00E+00 3.60E 01

lb lb lb lb lb lb

Tons Tons Tons Tons Tons Tons

Logs Logs Logs Logs Sawdust Sawdust

plywood plywood plywood plywood plywood plywood plywood plywood plywood plywood

Action

EF quality

Produced Produced Produced Produced Produced Produced Produced Produced Produced Produced

E E E D D D E E E E

Processed Processed Processed Processed Processed Processed

E E E E E E

a

MDI, methylene diphenyl diisocyanate; PF, phenol – formaldehyde; UF, urea – formaldehyde. NOx, nitrogen oxides; PM, particulate matter; SOx, sulfur oxides; VOCs, volatile organic compounds. Source: EPA Web Fire.

b

Appendix

Index 1995 Protocol for Equipment Leak Estimates, 101–2 AAC see alkylammonium compound ACC see acid copper chromate Acetaldehyde, 204–5 ACGIH see American Conference of Governmental Industrial Hygienists Acid copper chromate (ACC), 21 Acid sulfite pulping, 184–5 ACQ see ammoniacal copper quat Acrylonitrile (AN), 205–6 ACZA see ammoniacal copper zinc arsenate Adsorption, 197–8 Aeration ponds, 50–1 AF&PA see American Forest & Paper Association Air emissions: kilns, 32 pulp/paper mills, 179–260 wood-treatment, 55–6 Air pollution from wood-treatment: emission factors, 85–115 emission sources, 84–5 fugitive emissions from treated wood, 87–98 introduction, 83 wood-waste burning, 115–32 Alkylammonium compound (AAC), 23 American Conference of Governmental Industrial Hygienists (ACGIH), 208, 210, 216, 224 American Creosote Works, Florida, 66, 75–6 American Forest & Paper Association (AF&PA), 202 American Petroleum Institute (API), 102, 107, 109 American Wood Preservers’ Association (AWPA): air emissions, 99 carcinogenicity of preservatives, 83 Commodity Standards, 34

creosotes, 10, 27, 40 pentachlorophenol, 14 propiconazole, 23 vapor pressures, 66 water-borne preservatives, 20 wood treating chemicals, 135 Ammonia, 206–7 Ammoniacal copper arsenate, 40 Ammoniacal copper citrate (CC), 21 Ammoniacal copper quat (ACQ), 21, 40 Ammoniacal copper zinc arsenate (ACZA), 20 AN see acrylonitrile AP-42 see Compilation of Air Pollution Emission Factors API see American Petroleum Institute Arkwood Inc. site, Omaha, 78–9 Arsenicals, inorganic, 18–20 Ashes and soot, dioxins, 128–9 Average emission factor method, 102–3 AWPA see American Wood Preservers’ Association Baghouses, 195–7 Base catalysed decomposition (BCD), 77–8 BCD see base catalysed decomposition Benzene, 32, 207–9 ‘‘Benzene-soluble fraction’’ (CTPVs), 12–13 Biological Oxygen Demand (BOD), 247, 263–4 Bis(tri-n-butyltin) oxide (TBTO), 23 Bleaching of pulp, 186–9 BOD see Biological Oxygen Demand Boulton process, 31–2 Bush, George, W., 246 C&D see construction and demolition Calculation Workbook for Oil and Gas Production Equipment Fugitive Emissions, 102 California Air Pollution Control Offices Association (CAPCOA), 103, 105, 107

344

CAPCOA see California Air Pollution Control Offices Association Catalytic reactors, 193 CBA-A see copper azole type A CC see ammoniacal copper citrate CCA see chromated copper arsenate CDD see chlorodibenzo-p-dioxin CDDC see copper bis(dimethyldithiocarbamate) CDF see chlorodibenzofuran CEM see continuous emissions monitoring CERCLA see Comprehensive Environmental Response, Compensation and Liability Act CFB see circulating fluid bed Changing World Technologies (CWT), 153 Chemicals: preservation, 6–25 pulping, 182–3, 186, 202 wood-preserving, 1–26 Chemimechanical pulping, 262 Chemithermomechanical (CTMP) pulping, 262 Chemrec AB, 268–70 Chlorine, 210 Chlorine dioxide, 209 Chlorodibenzo- p-dioxin (CDD), 123 Chlorodibenzofuran (CDF), 123 Chloroform, 210–11 Chlorothalonil, 22 Chlorpyrifos (CPF), 22, 24 Chromated copper arsenate (CCA), 19, 20–1, 27, 41, 51, 76, 84, 99 Chromium (VI), 211–12 Circulating fluid bed (CFB), 266–7 Classified recycled fuel (REF), 266, 268 Cleaner production through gasification, 145–53 Cleaner production/pollution prevention (CP/P2), 156, 158–61 Cleaning and chipping, 181 Coal tar pitch volatiles (CTPVs), 92 Coal-tar: creosote, 6–8, 9–11, 52–3 description, 10 pitch, 10 Coal-tar pitch volatiles (CTPVs), 13–14 COE see CTPV

Index

COIs see constituents of interest Compilation of Air Pollution Emission Factors (AP-42), 83, 85–8, 90, 92–6, 98–100, 103, 228–9 Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), 63 Constituents of interest (COIs), 65 Construction and demolition (C&D), 44 Continuous emissions monitoring (CEM), 122, 131 Copper azole type A (CBA-A), 21 Copper bis(dimethyldithiocarbamate) (CDDC), 21 Copper naphthenate, 21–2 Correlation Equation Method, 105–7 CP/P2 see cleaner production/pollution prevention CPF see Chlorpyrifos Creosote, 27, 40, 65–6 Creosote coal tar, 10–11, 46, 53 Critchfield, David, 246 Cross-draught gasifiers, 148 Crossties, 2–3 CTMP see chemithermomechanical CTPVs see ‘‘benzene-soluble fraction’’ CWT see Changing World Technologies Cyclones for removing particles, 191–2 Destruction and removal efficiency (DRE), 121–2, 131, 146 4-5-Dichloro-2-N-octyl-isothiazolin-3one, 25 Diesel production, 152–3 Dioxins: ashes and soot, 128–9 emissions, 125–6, 127 properties, 213–14 wood-waste burning, 123–31 Direct-contact evaporators, 194–6 Douglas Fir, 2, 31, 40 Down-draught (co-current) gasifier, 148 DRE see destruction and removal efficiency (DRE) Drip pads and wood-treatment, 54–5, 56–64, 67, 138–9 Drippage (kickback) and wood-treatment, 53–4, 139

Index

ECF see elemental chlorine-free EFB see electrified filter bed EFRT see external floating roof tank Electrified filter bed (EFB), 109 Electrostatic precipitator (ESP), 197, 203 Elemental chlorine-free (ECF) processes, 189–90, 247, 263 Emergency Planning and Community Right-to-Know Act (EPCRA), 63 Emission factors: air pollution from wood-treatment, 85–115 equipment, 105 natural gas-fired engines, 104 polycyclic aromatic hydrocarbons, 90–2 process, 100 pulp and paper, 230–45 pulp/paper mills, 228–9 treated wood production form pole plant, 91 wood manufacturing practices, 132–3 wood manufacturing sectors, 294–342 Emissions: air pollution from wood-treatment, 84–5 constants, 89 dioxins, 125–6, 127 fugitive, 97 dust, 115 from spills, 114–15 kilns, 108–9 point source, 141–2 polycyclic aromatic hydrocarbons, 131–2 support equipment/piping components, 101–8 tank, 109–14 EMS see environmental management system Environmental management system (EMS), 144, 156–9, 161–5 Environmental policy checklist, 155 EPCRA see Emergency Planning and Community Right-to-Know Act Equipment emission factors, 105 ESP see electrostatic precipitator Ethylene glycol, 214–15

345

European Union (EU) Directive on releases to water, 17 External floating roof tank (EFRT), 110–13 Finishing of pulp, 189 Fischer, Franz, 153 Fischer–Tropsch (FT) process, 153 Fluidized-bed gasifier, 150–1 Formaldehyde, 215–16 Formic acid, 216–17 Fort James Operating Company Inc., Pennington, 251–2 Foster Wheeler, 266–8 FT see Fischer–Tropsch Fugitive emissions, 97, 114–15, 139 Furans and wood-waste burning, 123–31 Gasification and cleaner production, 145–53 Gasogene, 146 Granite and track ballast, 3 Graves, Lana, 251 Green Profits, 156 ‘‘Green’’ wood, 29 Handbook of Pollution Prevention Practices, 261 HAP see hazardous air pollutant Hardwoods, 2, 31, 34 Hart Creosoting Co., Texas, 73–4 Hazardous air pollutant (HAP): acetaldehyde, 204 ammonia, 207 chloroform, 211 dioxins, 213 formaldehyde, 215 hydrogen fluoride, 218 methanol, 220 phenol, 223 toluene, 226 Toxic Release Inventory, 201 Heating values, 119–20 Higgins Wood Preserving Co., Texas, 74–5 Hydrochloric acid, 217–18 Hydrogen fluoride, 218 Hydrogen sulfide, 218–19

346

IARC see International Agency for Research on Cancer IERs see initial environmental reviews IFRT see internal floating roof tank IGCC see integrated gasification combined cycle Ignition temperature, 119 Incinerators, 192–3 Incomplete combustion, 118 Initial environmental reviews (IERs): audit forms, 271–90 audit questionnaire, 165–78 objectives, 161–5 Inorganic arsenicals, 18–20 Integrated gasification combined cycle (IGCC), 261, 270 Internal floating roof tank (IFRT), 111–13 Internal rate of return (IRR), 266 International Agency for Research on Cancer (IARC), 11, 213, 224 International Paper Co.: Jay, 229, 246–8 Ticonderoga, 248–50 Vicksburg, 253 3-Iodo-2-propynyl butyl carbamate (IPBC), 23 IRR see internal rate of return Irving Pulp and Paper, St John mill, 250–1 ISO standards: 9000, 46, 48 9001, 46–8 14000, 159 14001, 154 Jasper Newsboy, 73 Kilns: drying, 31–3 emissions, 108–9 sticks, 45 Kimberley-Clark Corp., Everett, 250 Koppers Grenada Tie Treating Plant, Mississippi, 45, 54 Koppers site, Morrisville, North Carolina, 77–8 Koppers site, Oroville, California, 76–7 Koppers Wood Treating Company, 69–73

Index

Kraege, Carol, 250 Kraft pulping, 182, 183–4, 202–3, 263 Legal and due diligence compliance checklist, 162–4 Liquid petroleum gas (LPG), 14 Liquid wastes from wood-treatment, 48–55 Longview Fibre Co., Longview, 252–3 LPG see liquid petroleum gas Manganese dioxide, 65 Manual for Railway Engineering, 4 Martin, Roy, O., 95 Mass emissions calculations, 93–8 Mechanical pulping, 181–2, 186 MEK see methyl ethyl ketone Methanol, 230 Methyl ethyl ketone (MEK), 108 Methyl isobutyl ketone (MIBK), 108 Methyl mercaptan, 221 MIBK see methyl isobutyl ketone Microturbines, 152 Municipal solid waste (MSW), 44 Municipal Solid Waste Factbook, 179 Naphthalene, 69 NAPLs see non-aqueous-phase liquids Naptha treatment, 32–3 National Emission Trends (NET), 201 National Fire Protection Association (NFPA), 119 National Institute of Occupational Safety and Health (NIOSH), 1, 11, 18, 92, 135, 142–4 National Priorities List (NPL), 69 Natural gas-fired engines emission factors, 104 NET see National Emission Trends Neutral sulfite semi-chemical (NSSC) pulping, 182, 185–6 NIOSH see National Institute of Occupational Safety and Health Non-aqueous-phase liquids (NAPLs), 65 Non-pressure processes for wood preserving, 36–7 Non-pressure treatments, 24 NPL see National Priorities List NSSC see neutral sulfite semi-chemical

Index

Oak, 2, 34 Occupational Safety and Health Administration (OSHA), 1, 11, 17, 92, 209, 216, 251–2 Odor control, 198 Office of Air Quality Planning and Standards (OAQPS), 86 Open-core gasifiers, 149 OSHA see Occupational Safety and Health Administration Oxine copper (Copper-8-quinolinolate), 23 PAC see Public Advisory Committee Packaging Corporation of America, Tomahawk, 251 PAH see polycyclic aromatic hydrocarbons Pandrol clips, 2, 4 Particulate matter (PM), 108–9 PCBs see polychlorinated biphenyls PCDDs see polychlorinated dibenzodioxins PCDFs see polychlordibenzofurans PELs see permissible exposure limits Pentachlorophenol (PCP): Arkwood Inc. site, 78–9 biodegradation, 51–2 carcinogenicity, 1 chemical delivery, 27 chemical spills, 121 emission sources, 84 fugitive emissions from treated wood, 87 Koppers site, Oroville, 76 process emission factors, 101 properties, 14–19, 221–2 vapor pressure, 66, 70 Permissible exposure limits (PELs), 12, 17 Phenol, 223–4 PM see particulate matter POHCs see polyorganic hydrocarbons Point source emissions, 141–2 Pollution: controls, 43–81 fate, 65–9 introduction, 43 transport, 65–9 waste sources, 43–56

347

Pollution prevention: pulp and paper industry cleaner production, 265–71 initial environment reviews, 271–90 introduction, 261 P2 practices, 261–5 wood-preserving industry best practice/technology, 137–45 cleaner production through gasification, 145–54 environmental management systems, 154–78 introduction, 135 Polychlordibenzofurans (PCDFs), 15 Polychlorinated biphenyls (PCBs), 14 Polychlorinated dibenzodioxins (PCDDs), 15, 213 Polycyclic aromatic hydrocarbons (PAH): chemical spills, 121 creosote coal tars, 84 destruction and removal efficiency, 131 emissions, 131–2 fugitive emissions spills, 114 treated wood, 88–90, 92–4 incomplete combustion, 146 Koppers site, Oroville, 76 mass emission calculations, 96 preservation of wood, 6–12 toxic sludge, 45 vaporization, 67–9, 70 wood-waste burning, 115–16 Polyorganic hydrocarbons (POHCs), 121–2 Preservation: chemicals, 6–24 wood, 27–41 President’ s Commission on Environmental Quality, 246, 248 Pressure processes for wood preserving, 36–41 Pressurized fluidized-bed gasification, 151–2 Process emission factors, 98–101, 100 Propiconazole, 23 Public Advisory Committee (PAC), 248 Pulp and paper industry, pollution prevention, 261–91

348

Pulp/paper mills: air emissions case studies, 229, 246–53 chemicals of concern, 202–27 emission factors, 228–9, 230–45 introduction, 179–80 manufacturing technologies, 180–98 pollution sources, 199–202 regulations, 227–8 Pulping processes, 181–9 Radian Corporation, 131 Rail: industry, 2 profiles, 2 tracks, 2 RCRA see Resource Conservation and Recovery Act RDF see refuse-derived fuel Recommended exposure limits (RELs), 11–12, 17 Record of decision (ROD), 69, 76–7, 78, 79, 80 REF see classified recycled fuel Refuse-derived fuel (RDF), 266 RELs see recommended exposure limits Resource Conservation and Recovery Act (RCRA), 45, 48, 51, 58, 63–4, 77, 121 ROD see record of decision Screening Value Range Method, 103–5 Seasoning of wood, 30 Short-term exposure limit (STEL), 11–12 Sludge reduction, 140–1 Soda pulping, 182, 186 Solid wastes from wood-treatment, 43–8 Somerville Tie Plant, Texas, 32–3, 45–6, 49, 95 Southern pine, 2 Standards/retentions for chemicals and wood treatment, 35 STEL see short-term exposure limit Stoichiometric combustion, 116 Sulfite pulping, 164–5, 182 Sulfur dioxide, 224–6

Index

Sulfuric acid, 224, 225 Support equipment/piping components emissions, 101–8 Tank emissions, 109–14 ‘‘TANKS’’ software, 114 TBTO see Bis(tri-n-butyltin) oxide TCDD see 2,3,7,8-tetra chlordibenzo-pdioxin TCF see totally chlorine-free Tebucanazole (TEB), 24 TEF see toxicity equivalency factor Teflon, 218 2,3,7,8-tetra chlordibenzo- p-dioxin (TCDD), 213 Threshold limit values (TLVs), 92, 144 Tie plates, 3–4 Tie strength properties, 4–6 Timber preparation, 29–33 Time-weighted average (TWA), 11–12 TLVs see threshold limit values Toluene, 226–7 Totally chlorine-free pulp (TCF), 189, 190 Toxicity equivalency factor (TEF), 123, 213 Toxics Release Inventory (TRI), 92, 179, 201 Track ballast, 3 TRI see Toxics Release Inventory Tropsch, Hans, 153 TWA see time-weighted average UNEP see United Nations Environment Programme Unit-Specific Correlation Equation Method, 107–8 United Creosoting Site, Conroe, Texas, 79–80 United Kingdom (UK): Pesticide Safety Directorate, 17 Pollution Prevention and Control Regulations, 17–18 United Nations Environment Programme (UNEP), 17 United States Environmental Protection Agency (US EPA): 1995 Protocol for Equipment Leak Estimates, 101–2

Index

acetaldehyde, 204 air emissions, 83 Air Pollution Emission Factors (AP-42), 83, 85–8, 90, 92–6, 98–100 American Creosote Works, 76–7 ammonia, 207 Arkwood Inc. site, Omaha, 79 average emission factor method, 102 benzene, 207 carcinogenicity, 135 carcinogens, 1 case studies, 69 chlorine, 190, 210 chlorine dioxide, 209 chloroform, 211 ‘‘cluster rule’’, 190 coal-tar creosote, 11 creosote, 7, 10 dioxins/furans, 124 drip pads, 62, 64 ethylene glycol, 215 formaldehyde, 215 formic acid, 216 fugitive emissions from spills, 114 Hart Creosoting Co., 73 hazardous air pollutants, 203 hydrochloric acid, 217–18 hydrogen fluoride, 218 hydrogen sulfide, 219 Koppers site, Oroville, California, 76–7 Koppers Wood-treating Co., Carbondale, 71 methanol, 220 methyl mercaptan, 221 Municipal Solid Waste Factbook, 179 pentachlorophenol, 15–18, 222 phenol, 223 polycyclic aromatic hydrocarbons, 12 pulp/paper mills and odor control, 198 Sector Notebook, 169 sulfur dioxide, 225 sulfuric acid, 224 Superfund sites, 136 tank emissions, 110, 114 toluene, 226 Unit-Specific Correlation Equation Method, 107 wood-preserving processes, 54, 56–9

349

United States (US) Forest Service, 67, 93 Up-draught (counter-current) gasifiers, 147 Vapor pressures, 66–9, 70 Volatile organic compounds (VOCs): Air Pollution Emission Factors, 83 acetaldehyde, 204 acrylonitrile, 205 fugitive emissions spills, 114 treated wood, 87–8, 104–5, 108 process emission factors, 98, 104–5, 108 pulp/paper sector, 201–2 Waste reduction/pollution control/ sustainability in paper industry, 189–98 Waste sources and wood-waste burning, 115–23 Wastewater treatment, 50–1 Water-borne preservatives, 20 Water-repellent treatments, 23 WBO see World Bank Organization Wet scrubbers, 193–4 WHO see World Health Organization Wood: drying, 31 growth rings, 34 harvesting, 180–1 manufacturing practices and emission factors, 132–3 paper manufacturing, 180 preservation technology general facility overview, 27–9 introduction, 27 maximum temperature for preservatives, 40 process summary, 38–9 timber preparation, 29–33 wood treating, 33–41 products, 2–6 properties, 33–4 seasoning, 30 standards, 35 treating, 33–41 types, 2–6 Wood manufacturing sectors, emission factors, 294–342

350

Wood-preservation: chemicals, 1–6, 6–25 industry and pollution prevention, 135–78 Wood-treatment: air emissions, 55–6 drip pads, 56–64 drippage, 53–4, 139 liquid waste, 48–55 plant layout, 27–8 preservation, 33–41 processes, 38–9 solid waste, 43–8

Index

Wood-waste burning: dioxins and furans, 123–31 polycyclic aromatic hydrocarbons, 131–2 waste sources, 115–23 World Bank Organization (WBO), 15–16, 263–4 World Health Organization (WHO), 14–15 Xylene, 33 Zinc naphthenate, 20–3