NC0000272_Tech. Support Doc. BMPs_19960517

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J,�\SED ST41ES
i A ' UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
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< WASHINGTON, D.C. 20460
f,I,J,`cFDT�'GS
^. OFFICE OF
WATER
MAY 2 8 lone
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WATER?UALP SECTION
ASHEVILL REGIONAL OFFICE
May 17, 1996
Dear Reviewer:
Enclosed please find a preliminary draft of the document titled "Technical Support
Document for Best Management Practices Programs, Spent Pulping Liquor Management, Spill
Prevention, and Control" for the pulp and paper industry. This document has been prepared as
part of the U.S. Environmental Protection Agency's efforts to develop effluent limitations
guidelines and standards for this industry.
I would appreciate your review of this document. Because our schedule for this
rulemaking is on an accelerated basis, please return your comments to me within 30 days to the
following address:
U. S. Environmental Protection Agency
Engineering and Analysis Division(4303)
401 M Street S.W.
Washington, D.C. 20460
Sincerely,
Ronald P.Jrd dan
Engineering and Analysis Division
Enclosure
�6i} Recycled/Recyclable
Primed with Soyranota It*on paper thm
Contains at Is=50%recycled Neer

Addressees:
Dave Cochrane, EPA Region I
Andrew Seligman,EPA Region II
Richard Paiste, EPA Region III
Dee Stewart,Region IV
Marshall Hyatt, Region IV
Dave Soong, EPA Region V
Craig Weeks, EPA Region VI
Jeremy Johnstone, EPA Region IX
Patricia Bowlin,EPA Region IX
Dan Bodien,EPA Region X
Jane Engert,EPA OECA(2223 A)
Gregory Currey, EPA OWM(4203)
Brad Mahanes, EPA OECA(2243A)
Penny Lassiter, EPA OAR, OAQPS On?)
Mike Creason, Georgia Department of Natural Resources
Randy Teles4 Michigan Department of Environmental Quality
Joe DiMura,NewYork Department of Environmental Conservation
Forrest Westall,North Carolina Department of Environmental Health and Natural Resources
Mike Witt, Wisconsin Department of Natural Resources
John Daniel, Virginia Department of Environmental Quality
Marc Crooks, Washington Department of Ecology
Jessica Landman,NRDC
Lauren Blum, EDF
Mark Van Putten, NWF
Mark Floegel, Greenpeace
John Banks, Penobscot Nation Department of Natural Resources
Cathy Marshall, American Forest&Paper Association
Tom Kemeny, Georgia-Pacific Corporation
Ray Andreu,Buckeye Cellulose Corporation
Bill Hodgins, Union Camp Corporation
Doug Barton, The National Council of the Paper Industry for Air and Stream Improvement
Alan Lindsey, International Paper Co.
Curtis Barton, Stone Container Corporation
Tom Siegrist, Champion International
Alan Stinchfield, James River Corporation
Sara Kendall, Weyerhaeuser Paper Co.

DRAFT
TECHNICAL SUPPORT DOCUMENT
FOR
BEST MANAGEMENT PRACTICES PROGRAMS
SPENT PULPING LIQUOR MANAGEMENT, SPILL
PREVENTION, AND CONTROL
May 1996
Engineering and Analysis Division
Office of Science and Technology
Office of Water
U.S. Environmental Protection Agency
Washington, D.C. 20460
NRJ-088
0327-01.nq

TECHNICAL SUPPORT DOCUMENT
FOR
BEST MANAGEMENT PRACTICES PROGRAMS
SPENT PULPING LIQUOR MANAGEMENT, SPILL PREVENTION, AND CONTROL
Table of Contents
Page
1.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
2.0 LEGAL AUTHORITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
3.0 WOOD COMPOSITION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
4.0 WOOD PULPING AND CHEMICAL RECOVERY SYSTEMS . . . . 4-1
4.1 Pulping Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4.1.1 Mechanical Pulp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4.1.1.1 Stone Groundwood Pulp . . . . . . . . . . . . . . . . . . . 4-1
4.1.1.2 Refiner Mechanical Pulp . . . . . . . . . . . . . . . . . . 4-2
4.1.1.3 Thermomechanical Pulp . . . . . . . . . . . . . . . . . . . 4-2
4.1.2 Semi-Chemical Pulp . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
4.1.3 Chemical Pulp . . . . . . . . _ . . . . . . . . . . . . . . . . . . . . . . 4-3
4.2 Pulping and Chemical Recovery Systems . . . . . . . . . . . . . . . . . 4-5
4.2.1 Kraft and Soda Pulping . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
4.2.2 Sulfite Pulping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
4.2.3 Semi-Chemical Pulping . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
5.0 COMPOSITION AND TOXICITY OF PULPING LIQUORS . . . . . . 5-1
5.1 Kraft Mill Black Liquor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
5.2 Sulfite Pulping Liquors (Red Liquors) . . . . . . . . . . . . . . . . . . . 5-3
5.3 Semi-Chemical Pulping Liquors . . . . . . . . . . . . . . . . . . . . . . . . 5-3
5.4 Toxicity of Pulping Liquors . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
5.5 Toxic Pollutants Found in Spent Pulping Liquors . . . . . . . . . . . 5-6
6.0 SOURCES OF SPENT PULPING LIQUOR LOSSES . . . . . . . . . . . . 6-1
6.1 Kraft and Soda Mills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
6.2 Sulfite Mills and Semi-Chemical Mills . . . . . . . . . . . . . . . . . . . 6-2
6.3 Summary of Reported Pulping Liquor Spills . . . . . . . . . . . . . . 6-2
6.4 Untreated Wastewater Loadings for Kraft Mill . . . . . . . . . . . . 6-4
6.5 Untreated Wastewater Loadings for Sulfite Mill . . . . . . . . . . . 6-5
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0327-01.nq i

Table of Contents (Continued)
Page
7.0 SPENT PULPING LIQUOR MANAGEMENT, SPILL PREVENTION, AND
CONTROL: CURRENT INDUSTRY PRACTICE . . . . . . . . . . ... . . 7-1
7.1 Kraft and Soda Mills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
7.1.1 'Management Commitment . . . . . . . . . . . . . . . . . . . . . . 7-3
7.1.2 Equipment Requirements . . . . . . . . . . . . . . . . . . . . . . . 7-5
7.1.3 Economical Recovery of Spent Kraft Pulping Liquors . . 7-7
7.2 Sulfite Mills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-9
8.0 BMP REGULATORY APPROACH, REQUIREMENTS, AND
IMPLEMENTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1
8.1 Regulatory Approach and Regulatory Requirements . . . . . . . . 8-1
8.2 Implementation Guidance for Permit Writers and Pretreatment
Authorities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
8.2.1 Applicability of BMP Regulation to Pulping Liquors
Other Than Spent Pulping Liquor . . . . . . . . . . . . . . . . . 8-6
8.2.2 Requirements for Specific BMP Equipment Items . . 8-6
8.2.3 Costs of BMP Compliance . . . . . . . . . . . . . . . . . . . . . . 8-7
8.2.4 Recovery of Liquor Solids Under BMP Regulation . . . . 8-7
8.2.5 Monitoring of BMP Implementation . . . . . . . . . . . . . . . 8-8
9.0 ESTIMATED COSTS AND EFFLUENT REDUCTION BENEFITS 9-1
9.1 Current Status of Spent Pulping Liquor Spill Prevention and
Control Systems in United States . . . . . . . . . . . . . . . . . . . . . . . 9-1
9.2 Equipment Costs for BMP Implementation at Pulp and Paper
Mills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2
9.3 Costs and Effluent Reductions - Mill Case Studies . . . . . . . . . . 9-4
9.3.1 Southern U.S. Bleached Kraft Mill . . . . . . . . . . . . . . . . 9-5
9.3.2 Canadian Bleached Kraft Mill . . . . . . . . . . . . . . . . . . . . 9-7
9.4 General Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-9
References
ATTACHMENT A Best Management Practices Regulation
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0327-01.nq ll

LIST OF TABLES
Page
3-1 Extractive Compounds Associated with Wood Pulping Operations . . . . . . . . 3-3
4-1 Comparison of Kraft and Sulfite Pulping Processes . . . . . . . . . . . . . . . . . . . . 4-9
5-1 Inorganic Content of Black Liquors (Weight Percent, Dry Solids Basis) . . . . 5-7
5-2 Components in Black Liquors (Weight Percent, Dry Solids Basis) . . . . . . . . . 5-8
5-3 Composition of Calcium Base and Magnesium Base Sulfite Pulping Liquors . 5-9
5-4 Composition of Ammonia Base and Sodium Base Sulfite Pulping Liquors . . . 5-10
5-5 Composition of Typical Fresh NSSC Pulping Liquors . . . . . . . . . . . . . . . . . . 5-11
5-6 Composition of Typical Spent NSSC Pulping Liquors . . . . . . . . . . . . . . . . . . 5-12
5-7 Minimum Lethal Concentrations to Daphnia and Fathead Minnows of
Components of Kraft Pulp Mill Wastewaters . . . . . . . . . . . . . . . . . . . . . . . . 5-13
5-8 Critical Concentrations (Minimum Lethal Doses) to Fish of Components of
Sulfate (Kraft) Liquors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14
5-9 Toxic Wastewater Pollutants and Hazardous Air Pollutants Found in Spent
Pulping Liquors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15
6-1 Summary of Reported Pulping Liquor Spills, EPA Emergency Response
Notification System (ERNS) Database (January 1988 - March 1993) . . . . . . . 6-6
6-2 Typical Untreated Wastewater Loadings From an Ideal Bleached Kraft
Mill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
6-3 Examples of Untreated Wastewater Loadings for Two Sulfite Mills . . . . . . . 6-8
7-1 Black Liquor Storage Capacity - Kraft and Soda Mills, Tank Volume
(Gallons) and Typical Operating Level (%) . . . . . . . . . . . . . . . . . . . . . . . . . 7-11
7-2 Pulping Liquor Storage Capacity - Sulfite Mills, Tank Volume (Gallons) and
Typical Operating Level (%) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-12
`Ri-0sa
0327-01.nt Ill

LIST OF TABLES (Continued)
Page
9-1 BMP Implementation Status for Spent Pulping Liquor Control Systems at
Bleached Kraft Mills, Soda Mills, and Sulfite Mills . . . . . . . . . . . . . . . . . . . . 9-13
9-2 BMP Investment Cost Estimates for Kraft Mills . . . . . . . . . . . . . . . . . . . . . . 9-14
9-3 BMP Investment Cost Estimates for Sulfite Mills . . . . . . . . . . . . . . . . . . . . . 9-15
9-4 Effects of Spent Pulping Liquor Control Systems on POTW Effluent Quality
at a Southern U.S. Kraft Mill Discharging to POTW . . . . . . . . . . . . . . . . . . 9-16
9-5 Quantified Effluent Reduction Benefits From Spent Pulping Liquor Control
System at a Kraft Mill Without Secondary Treatment . . . . . . . . . . . . . . . . . . 9-17
NRu-0ss
0327-01.n� iv

LIST OF FIGURES
Page
4-1 Kraft Process, Simplified Schematic Diagram . . . . . . . . . . . . . . . . . . . . . . . . 4-11
4-2 Kraft Pulping and Chemical Recovery, Simplified Schematic Diagram . . . . . 4-12
4-3 Ammonia Base Sulfite Pulping, Simplified Schematic Diagram . . . . . . . . . . . 4-13
4-4 Calcium Base Sulfite Pulping, Simplified Schematic Diagram . . . . . . . . . . . . 4-14
4-5 Sodium Base Sulfite Pulping, Simplified Schematic Diagram . . . . . . . . . . . . . 4-15
4-6 Magnesium Base Sulfite Pulping, Simplified Schematic Diagram . . . . . . . . . . 4-16
4-7 Sulfite Recovery Systems Currently in Use . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17
4-8 Semi-Chemical Pulping Mill Utilizing Continuous Digestion, Simplified
Schematic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-18
4-9 Fluidized Bed System For Treatment of NSSC Waste Liquor, Simplified
Schematic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19
7-1 Black Liquor Solids vs. Conductivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-13
8-1 Wastewater Treatment Influent COD Levels Without BMPs . . . . . . . . . . . . . 8-11
8-2 Wastewater Treatment Influent COD Levels With BMPs . . . . . . . . . . . . . . . 8-12
9-1 Effect of Spent Pulping Liquor Control Systems on POTW Effluent Flow at
a Kraft Mill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-18
9-2 Effect of Spent Pulping Liquor Control Systems on POTW Influent COD
Levels at a Kraft Mill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-19
9-3 Effect of Spent Pulping Liquor Control Systems on POTW Effluent COD
Levels at a Kraft Mill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-20
9-4 Effect of Spent Pulping Liquor Control Systems on TSS Levels at a Kraft
Mill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-21
9-5 Effect of Spent Pulping Liquor Control Systems on BOD, Levels at a Kraft
Mill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-22
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0327-01.nj v

LIST OF FIGURES (Continued)
Page
9-6 Effect of Spent Pulping Liquor Control Systems on a Turpentine Spill at a
KraftMill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-23
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0327-01.nq vi

TECHNICAL SUPPORT DOCUMENT
FOR
BEST MANAGEMENT PRACTICES PROGRAMS
SPENT PULPING LIQUOR MANAGEMENT, SPILL PREVENTION, AND CONTROL
1.0 INTRODUCTION
The Federal Water Pollution Control Act of 1972 (also known as the Clean Water Act
(CWA)) established several programs to restore and maintain the quality of the nation's
surface waters. For point source industrial dischargers, one of the most important programs
involved the development and implementation of technology-based effluent limitations
guidelines and standards for discharges to surface waters (direct discharges) and
pretreatment standards for industrial discharges to Publicly Owned Treatment Works
(POTWs) (indirect discharges). Section 304(m) of the Water Quality Act of 1987 requires
that the U.S. Environmental Protection Agency (EPA) review and revise, as necessary,
technology-based effluent limitations guidelines and standards promulgated pursuant to
Sections 301, 304, and 306.
The Engineering and Analysis Division (EAD) within EPA's Office of Water has the
primary responsibility for conducting the periodic review of technology-based effluent
limitations and standards applicable to industrial categories, including the Pulp, Paper and
Paperboard Point Source Category. EAD's responsibilities include:
(1) Gathering, developing, and evaluating background information and data
regarding industrial process operations; types and quantities of pollutants
generated; process and non-process water use; effectiveness and cost of
process changes and wastewater treatment methods; and financial and
economic status of the industry;
(2) Ensuring the adequacy and validity of engineering, scientific, and economic
data and findings used as support for the effluent limitations guidelines and
standards;
(3) Developing effluent limitations guidelines for existing direct discharges; new
source performance standards for new direct discharges; pretreatment
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1.0 Introduction
standards for existing and new indirect discharges; and Best Management
Practices (BMPs) programs for proposal and promulgation by the EPA
Administrator; and
(4) Developing technical information that may be required by judicial review of
promulgated effluent guidelines and standards.
There are six types of technology-based effluent limitations guidelines and standards:
Abbreviation Effluent Limitations Guideline or Standard
BPT Best Practicable Control Technology Currently Available
BAT Best Available Technology Economically Achievable
BGT Best Conventional Pollutant Control Technology
NSPS New Source Performance Standards
PSES Pretreatment Standards for Existing Sources
PSNS Pretreatment Standards for New Sources
EPA promulgates these technology-based effluent limitations and standards for three major
classes of pollutants: (1) conventional pollutants; (2) priority pollutants; and (3) non-
conventional pollutants. Conventional pollutants are those defined in Section 304(a)(4) of
the CWA, or designated by the EPA Administrator pursuant to Section 304, namely total
suspended solids (TSS), biochemical oxygen demand (BODS), oil and grease, fecal coliform,
and pH. Analytical measures of TSS, BOD3, and oil and grease are not chemical-specific
determinations; they are aggregate measures of suspended particulates, oxygen-demanding
substances, and freon-extractable substances in water, respectively. Specific compounds
contributing to these measures may or may not exhibit toxic effects and may or not be
among the 126 designated priority pollutants as defined by the CWA. The priority
pollutants are specifically designated elements or compounds that exhibit toxic effects in
aquatic systems. If these pollutants are determined to be present at significant levels, they
must be regulated by categorical technology-based effluent limitations guidelines and
standards pursuant to Section 301(b)(2)(A) of the CWA. Non-conventional pollutants are
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0327-01.nq
1-2

1.0 Introduction
all other pollutants that are neither the 5 listed conventional pollutants nor the 126 toxic
pollutants designated as priority pollutants. Non-conventional pollutants may be aggregate
measures such as chemical oxygen demand (COD) or adsorbable organic halides (AOX),
or specific elements or compounds such as chlorine (02), ammonia-nitrogen (NH3-N), or
2,3,7,8-tetrachlorodibenzofuran (2,3,7,8-TCDF). Non-conventional pollutants can be non-
toxic (e.g., iron at low levels) or exhibit toxic effects (e.g., 2,3,7,8-TCDF). If determined to
be present at significant levels, non-conventional pollutants must be regulated by categorical
effluent limitations guidelines and standards pursuant to Section 301(b)(2)(A) of the CWA.
As part of its review of the. industry, EPA identified the following pollutants or pollutant
parameters as present in pulp, paper, and paperboard wastewaters and determined they
should be subject to limitation under BPT, BCt, and BAT effluent limitations guidelines;
NSPS; PSNS; and PSES, as appropriate:
Conventional Pollutants: Biochemical oxygen demand (BODO
Total suspended solids (TSS)
pH .
Priority Pollutants: 2,3,7,8-Tetrachlorodibenzo p-dioxin (2,3,7,8-TCDD)
Chloroform
Pentachlorophenol (PCP)
2,4,6-Trichlorophenol
Non-Conventional Pollutants: Adsorbable organic halides (AOX)
Chemical oxygen demand (COD)
2,3,7,8-Tetrachlorodibenzofuran (2,3,7,8-TCDF)
Tetrachlorocatechol
Tetrachloroguaiacol
Trichlorosyringol
2,4,5-Trichlorophenol
314,5-Trichlorocatechol
3,4,5-Trichloroguaiacol
3,4,6-Trichlorocatechol
3,4,6-Trichloroguaiacol
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1.0 Introduction
Non-Conventional Pollutants: 4,5,6-Trichloroguaiacol
(Continued) 2,3,4,6-Tetrachlorophenol
For the Pulp, Paper and Paperboard Point Source Category, EPA has promulgated effluent
limitations guidelines for the conventional pollutants TSS, BOD,, and pH for various
subcategories based on BCT. Effluent limitations guidelines and standards for the priority
and non-conventional pollutants will be based on BAT, PSES, and PSNS. For new sources,
EPA is promulgating standards for all pollutants selected for regulation based on NSPS.
Effluent limitations guidelines and standards are implemented through National Pollutant
Discharge Elimination System(NPDES) permits issued by EPA or authorized state agencies
pursuant to Section 402 of the CWA, and through pretreatment programs administered by
state agencies and designated municipal pretreatment authorities.
In addition to pollutant-specific effluent limitations guidelines and standards, EPA has
promulgated BMPs pursuant to Section 304(e), 307, and Section 402(a)(1)(B) of the CWA
for Subcategory B - Bleached Papergrade Kraft and Soda, and Subcategory E - Papergrade
Sulfite. EPA anticipates promulgating similar BMPs for the following proposed
subcategories at a later time:
Subcategory A Dissolving Kraft
Subcategory C Unbleached Kraft
Subcategory D Dissolving Sulfite
Subcategory F Semi-Chemical
Subcategory H Non-Wood Chemical
The BMPs establish controls which will reduce the release of toxic, conventional, and non-
conventional pollutants to navigable waters. The principal objective of the BMPs is to
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1.0 Introduction
prevent losses and spills of spent pulping liquor (also referred to as 'black pulping liquor")
from equipment items in pulping liquor service; the secondary objective is to contain, collect,
and recover, or otherwise control, spills and ii_ --s that do occur. The BMPs are also
applicable to pulping by-products, such as turpentine and soap, for mills that process these
items.
Economic operation of kraft and sulfite pulping processes is predicated on the recovery of
inorganic pulping liquor chemicals and energy from the organic material dissolved from the
wood supply during the pulping processes. However, the nature of pulp screening/ washing
and pulping liquor recovery systems is such that losses of spent pulping liquors (i.e., kraft
black liquor, sulfite red liquor) are routine. Liquor is lost from seals on brownstock
washers, pumps and valves in liquor service, knotters and screens, sewered evaporator boil-
out solutions, and other intentional liquor diversions during maintenance, startups and
shutdowns. Spent pulping liquor is also lost in spills resulting from process upsets, tank
overflows, mechanical breakdowns, operator errors, and construction activities. Research
into spill incidents reported through EPXs Emergency Response Notification System shows
that only a few pulping liquor spills have resulted from catastrophic failures of bulk liquor
storage tanks. Mechanical failure was cited in 45% of reported liquor spills, human error
in 20%, tank overfilling in 16%, and intentional diversions in 4%. The cause of 13% of the
spills was reported as unknown.
Liquor losses and spills not only adversely affect economic operation of the pulping process
but can also adversely affect wastewater treatment system operations and lead to increased
effluent discharges of conventional and toxic pollutants. These wastewater treatment
systems operate most effectively when influent variability is minimised. Thus, achievement
of minimum effluent discharges is only possible at mills where routine liquor losses,
intentional liquor diversions, and unintentional liquor spills are effectively controlled.
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1.0 Introduction
EAD has emphasized the control of spent pulping liquor losses from chemical pulp mills to
control toxic pollutants for the following reasons:
(1) Spent pulping liquor spills and intentional liquor diversions are a principal
cause of upsets and loss of efficiency in biological wastewater treatment
systems that are nearly universally used for the treatment of chemical pulp
mill wastewaters. The resulting interference with biological treatment system
operations can lead to pass-through of conventional pollutants, priority
pollutants, and non-conventional pollutants that would otherwise be treated
or removed.
(2) Losses of pulping liquor contribute significant portions of the untreated
wastewater loadings and discharge loadings of color, oxygen-demanding
substances, and non-chlorinated toxic compounds from chemical pulp mills.
The non-chlorinated, non-conventional pollutants that exhibit toxic effects
will not be regulated with compound-specific effluent limitations guidelines
and standards as part of BAT, NSPS, PSES, or PSNS.
(3) Prevention and control of spent pulping liquor losses is a form of pollution
prevention that will result in less demand for pulping liquor make-up
chemicals; increased energy efficiency through recovery of liquor solids; more
effective and less costly wastewater treatment system operations; and reduced
formation of wastewater treatment sludges.
(4) Control of spent pulping liquor losses will result in incidental reductions in
atmospheric emissions of Total Reduced Sulfur (TRS) compounds from kraft
mills and volatile hazardous air pollutants (HAPs) from all chemical pulp
mills.
The purpose of this document is to present EAD's findings with respect to spent pulping
liquor loss control from pulping and chemical recovery operations and to present the BMPs
for chemical pulp mills. Section 2.0 establishes EPA's legal authority to promulgate BMPs
as part of the categorical effluent limitations guidelines and standards. Wood composition
is described in Section 3.0. The major chemical pulping and recovery processes are briefly
reviewed in Section 4.0. The chemical composition and toxicity of pulping liquors are
described in Section 5.0. Sources of pulping liquor losses are described in Section 6.0.
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1.0 Introduction
Current industry practices regarding spent pulping liquor management, spill prevention, and
control are reviewed in Section 7.0. EPA's BMPs are described in Section 8.0. Estimated
costs, effluent reduction benefits, and current industry status with respect to implementation
of spent pulping liquor BMPs are presented in Section 9.0. References are provided at the
end of the document. Tables and figures appear at the end of each section.
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0327-0I.nq 1.7

2.0 LEGAL AUTHORITY
EPXs legal authority for establishing these BMPs is found in Section 304(e), Section
307(b) and (c), Section 402(a)(1), and Section 501(a) of the CWA.
Section 304(e) provides as follows:
'The Administrator, after consultation with appropriate Federal and State
agencies and other interested persons, may publish regulations, supplemental
to any effluent limitations specified under subsections (b) and (c) of this
section for a class or category of point sources, for any specific pollutant which
the Administrator is charged with a duty to regulate as a toxic or hazardous
pollutant under section 307(a)(1) or 311 of this Act, to control plant site
runoff, spillage or leaks, sludge or waste disposal, and drainage from raw
material storage which the Administrator determines are associated with or
ancillary to the industrial manufacturing or treatment process within such class
or category of point sources and may contribute significant amounts of such
pollutants to navigable waters. Any applicable controls established under this
subsection shall be included as a requirement for the purposes of section 301,
302,306,307, or 403, as the case may be, in any permit issued to a point
source pursuant to section 402 of this Act."
With respect to spent pulping liquor, the BMPs are directed at preventing and
controlling spills, leaks, and intentional diversions of spent pulping liquors associated
with the various chemical pulping processes to minimise discharges of priority pollutants
(e.g., phenol and certain toxic metals). An added benefit is the reduced discharge of
non-conventional pollutants present in spent pulping liquors that exhibit toxicity in
aquatic systems. An incidental benefit is the reduced discharge of conventional
pollutants (TSS and BODS) and non-conventional pollutants (COD, color, resins, and
fatty acids) associated with the spent pulping liquors. The toxic pollutants addressed by
these BMPs would otherwise enter navigable waters in significant amounts, thus justifying
GPA's exercise of its authority under Section 304(e).
NRJ-088
0327-01.nri 2-1

2.0 Legal Authority
Section 402(a)(1) authorizes the EPA Administrator to issue a permit for the discharge
of a pollutant or pollutant(s) "... upon condition that such discharge will meet . . . such
conditions as the Administrator determines are necessary to carry out the provisions of
this Act." Among other things, this provision authorizes the permitting authority to
impose BMPs in NPDES permits on a case-by-case basis.
EPA has concluded for the reasons set forth below and elsewhere in this document that
all pulp and paper mills subject to Subparts B or E should be required to prepare and
implement a BMP Plan for spent pulping liquors, soap, and turpentine. To provide for
consistency and administrative convenience, EPA has decided to establish its BMP
conditions on a categorical basis, rather than on a permit-by-permit basis. However, the
BMP regulation reserves considerable discretion and flexibility to individual permittees
to determine the appropriate type and mix of BMPs at their facilities.
Consistent with 40 Code of Federal Regulations (CFR) §122.44(k), BMPs specified under
Section 402(a)(1) of the CWA -- whether by regulation or on a permit-by-permit basis --
are not limited to the implementation of BMPs established under CWA Section 304(e).
Rather, they may also be imposed to: 1) control or abate the discharge of any pollutant
whenever the derivation of numeric effluent limitations is infeasible or when the
practices are reasonably necessary to achieve effluent limitations and standards, or 2)
fulfill the purposes and intent of the CWA.
As set forth in more detail in Sections 5.0 through 9.0, EPA has determined that
implementation of BMP Plans will significantly reduce the discharge of priority
pollutants and other pollutants that exhibit toxic effects in the environment. EPA
believes that controlling spent pulping liquors and abating their toxic effects, in particular
through BMPs, fulfills the purposes and intent of the CWA and is a step toward the
CWA's goal of eliminating the discharge of toxic pollutants (Section 101(a)(3)).
NRI-088
0327-01.nd 2-2

2.0 Legal Authority
As authority for imposing the BMP requirement on indirect dischargers subject to
Subparts B or E, EPA relies on Section 307(b) and (c) of the CWA. Pretreatment
standards for new and existing sources under Section 307 are designed to prevent the
discharge of pollutants that pass through POTWs or that interfere with or are otherwise
incompatible with treatment processes or sludge disposal methods at POTWs. For
example, based on data collected from 1988 through 1992 at a POTW, EPA has
determined that black liquor spills and leaks from an industrial user mill contributed
significantly to chronic toxicity to Daphnia in the fully treated POTW effluent. The data
further show that the toxic effects of the POTW's effluent have been reduced since
implementation of effective spent pulping liquor management, spill prevention, and
control at the mill (see Sections 5.5 and 9.4). Therefore, EPA has determined that
pollutants in black pulping liquor, in the absence of controls on spills, leaks, and
intentional diversions, can cause interference and pass-through at POTWs. For this
reason, EPA believes that it is appropriate to include as part of its pretreatment
standards the requirement that mills prepare and implement BMP Plans in accordance
with this regulation.
Under Section 501(a), the Administrator has authority to prescribe such regulations as
are necessary to carry out her functions under the Clean Water Act. The promulgation
of BMPs on a categorical basis to control toxic pollutants and other pollutants of concern
not only promotes efficient administration of the NPDES permit program and the
pretreatment program, but also provides an important step, consistent with Section 304,
307, and 402, of achieving the goals of the CWA.
NPJ-088
0327-01.n� 2-3

3.0 WOOD COMPOSITION
The principal components of wood are cellulose, hemicelluloses, lignin, and extractives.
Cellulose is a linear polysaccharide consisting of B-D-glucosy ranose units linked by (1-4)-
glucosidic bonds. Cellulose molecules are bundled together in wood to form microfibrils,
which in turn build up to form fibrils, and finally cellulose fibers. About 40% of most wood
is cellulose that has a molecular weight of greater than 10,000. (1)
Hemicelluloses are composed of different carbohydrate units. Unlike cellulose,
hemicelluloses are branched to various degrees, and their molecular masses are much lower.
The content and type of hemicellulose found in softwoods differ considerably from those
found in hardwoods. In softwoods, galactoglucomannans (15-20% by weight),
arabinoglucuronoxylan (5-10%), and arabinogalactan (2-3%) are the most common
hemicelluloses; in hardwoods, glucuronoxylan (20-30%) and glucomannan (1-5%) are the
most common hemicelluloses. (1)
Lignin is essentially an aromatic polymer. It is formed in wood by an enzyme-initiated
dehydrogenative polymerization of a mixture of three different 4-hydroxyarylpropenyl
alcohols. The proportions of these alcohols vary with different wood species. Softwood
lignin is largely a polymerization product of coniferyl alcohol. The aromatic content of
softwood lignin, expressed as monomeric phenol, is about 50%. In hardwoods, lignin is
formed by copolymerization of coniferyl and sinapyl alcohols. Cigna is probably chemically
linked to hemicelluloses. The relative molecular mass of native lignin is considered infinite.
Lignin imparts rigidity to the fiber walls and acts s a bonding agent between fibers. (1)
"Extractives" are components of the wood that can be extracted by organic solvents such as
ethanol,acetone, or dichloromethane. Extractives include aliphatic extractives,which consist
of fats and waxes; phenolic extractives, which consist of hydrolyzable tannins, flavonoids,
ligands,stilbenes, and tropolines; and terpenoid compounds (found only in softwoods),which
include mono-, sesqui-, and diterpenes; and various resin acids. The amount of extractives
NFU-088
0327-01.nn 3-1

3.0 Wood Composition
in wood varies greatly (1.5 to 5%), depending on the species, place of growth, and age of
the tree (1). Many of the compounds classified as extractives, particularly the resin and fatty
acids, which are discharged in wastewaters from pulping operations, have been found to be
toxic to aquatic life (2,3,4,5). Table 3-1 summarizes some of the extractives found in
wastewaters from kraft, sulfite, and mechanical pulping operations. Although many of these
compounds exhibit toxicity to aquatic life, they have not been designated as "priority
pollutants" under the CWA by EPA.
NPJ-088
0327-01.ntj 3-2

3.0 Wood Composition
Table 3.1
Extractive Compounds Associated with Wood Pulping Operations
Extractive Kraft Sulfite Mechanical
Compound Pulpmg Pulping Pulping
Resin Acds
Abietie / ! I
Dehydroabine J J !
19CQIIDaIiC ! J J
Pimanc / ! /
Smduecopmanc J J J
Neasbiebe
Uossmnted Psdy Acids
oleic J I
Linoleic J J J
Lmolceic
Pahuitolcie !
Diterpioe Aleobols
Pimarol !
60pimarol !
Abieool J
12E-abieaol J
13ep®aood J
Juvsbianes
Jwsbione ! J
Ju abiol J !
s1'dchydrajwabicnc ! /
a l'dehydrojwabiol
Ligoin DegndaGco Products
Eugenol J
lsoeugeool
3,3'-0imcthoxyJ,4'dihydmxysWbese !
Sources: Kringstad and Lindstrom, 1984 (1); Springer, 1986 (2); Leach and Thakore, 1974 (3).
RJ-088
0327-01.rtrj 3-3

4.0 WOOD PULPING AND CHEMICAL. RECOVERY SYSTEMS
4.1 Pulsing Processes [Note - 1994 or 1995 data will be used in final report]
In 1992, the United States pulp and paper industry produced nearly 66 million tons of wood
pulp by the following processes (6):
Process Percent of Production Thousands of Tons
Bleached Sulfate (Kraft) 45.0 29,703
Unbleached Sulfate 33.7 22,228
Semi-Chemical 6.2 4,101
Thermomechanical 5.4 3,584
Groundwood and Refiner 4.4 2,917
Total Sulfite 2.2 1,427
Dissolving and Special Alpha 2.1 1,383
Other —1.0 600
Total 1 100.0 65,943
The distinguishing characteristics and major products associated with these pulping processes
are summarized below.
4.1.1 Mechanical Pulp
4.1.1.1 Stone Groundwood Pulp
Stone groundwood pulp is produced by forcing logs against a grindstone by mechanical
pressure. Nearly all of the log is converted into a low-grade pulp used primarily for
newsprint and other products where permanence is not an important factor. Lignin, which
binds wood fibers together, imparts color to pulp, and causes paper to yellow, is not
removed in this process. Other products made from stone groundwood pulp include towels,
inexpensive writing paper, and molded products such as egg cartons.
NRJ-088
0327-01.nn 4-1

4.0 Wood Pulping and Chemical Recovery Systems
For newsprint production, groundwood pulp is usually blended with about 20 % chemical
pulp for added strength. Groundwood pulp is usually not bleached; if it is bleached, it is
not bleached to a high degree of brightness. The frayed and broken fibers obtained from
groundwood pulping are quick to absorb printing inks and thus are suitable for high-speed
printing.
4.1.1.2 Refiner Mechanical Pulp
In this process, wood chips are passed through double-disc steel refiners, where the fibers
are mechanically separated rather than ground on a stone. The fibers are frayed for better
bonding, but they are not chopped indiscriminately as in the stone groundwood process.
Consequently, refiner mechanical pulp is stronger than stone groundwood pulp and is more
suitable for certain uses where strength is an important factor.
4.1.1.3 Thermomechanical Pulp
Thermomechanical pulp is produced by preheating wood chips with steam before refining
(as described in Section 4.1.1.2). The heat acts to soften the lignin, which binds the wood
fibers together and promotes fiber separation. This process results in a stronger pulp than
that produced by the groundwood process and minimizes the need for more expensive
chemical pulp in newsprint production.
4.1.2 Semi-Chemical Pulp
In this process, wood chips are processed in a relatively mild chemical solution before
mechanical refining for fiber separation, usually with disc refiners. The chemical solution
most often consists of a sodium sulfite/sodium carbonate liquor which acts to soften the
lignin and promote fiber separation; thus, the product is often called neutral sulfite semi-
vtu-osa
0327-01.nr 4-2

4.0 Wood Pulping and Chemical Recovery Systems
chemical (NSSC) pulp. Other pulping liquors and chemical solutions may also be used to
produce semi-chemical pulp. The yield of semi-chemical pulping depends on the specific
process used; it ranges from 65 to 8517o. Most semi-chemical pulp is not bleached and is
used for corrugated board, newsprint, and specialty boards. Bleached NSSC pulp can be
used to manufacture writing and bond papers, offset papers, tissues, and towels.
4.1.3 Chemical Pulp [Note - 1994 or 1995 data will be used for final report]
More than 90% of the wood pulp manufactured in the United States is produced by the
kraft (sulfate) and sulfite chemical pulping processes (6). The purposes of chemical pulping
are to remove lignin to facilitate fiber separation and to improve the papermaking
properties of the fibers. The kraft process is the most widely used commercial process by
far, accounting for more than 88% of U.S. wood pulp production in 1992 (6). Dissolving
kraft and sulfite mills are operated to produce high-grade cellulose pulp for selected product
applications. Soda pulping is similar to kraft pulping, except that sulfur is not intentionally
added to the cooking liquor. A summary of the number of mills using various pulping
processes is provided below (7):
Number of Mills With
Type of Mill Number of Mills Bleaching
Kraft and Soda Mills
Dissolving Grade Kraft 3 3
Papergrade Kraft 107 85
Papergrade Soda 2 2
Total 112 90
Sulfite Mills
Dissolving Grade Sulfite 4 4
Papergrade Sulfite 11 10
Total 15 14
NRJ-M
0327-01.nr 4-3

4.0 .Vood Pulping and Chemical Recovery Systems
.Kraft'pulping entails treating wood chips in the range of 170°C under pressure with an
alkaline pulping liquor that contains sodium hydroxide (NaOH) and sodium sulfide (Na2S).
The pulping liquor and pulping conditions promote cleavage of the various ether bonds in
the lignin. The lignin degradation products dissolve in the liquor. Sodium sulfate (Na2S0,)
and lime (CaO) are used to replenish the pulping liquor as part of the chemical and energy
recovery operations associated with the process. Depending on pulping conditions, as much
as 90-95% of the lignin can be removed from wood in kraft pulping (1). The yield for kraft
pulping is typically about 50%. In kraft pulping for the production of bleached pulp, more
than 55010 of the total weight of wood is dissolved in the pulping liquor.
Portions of the wood polysaccharides, especially those associated with the hemicelluloses,
and most of the wood extractives, are dissolved in the kraft pulping liquor. If softwood is
the raw material, the extractives can be recovered as by-products such as sulfate turpentine
and tall oil. Turpentine contains a mixture of the lower terpenes, whereas raw tall oil
consists mainly of fatty and resin acids. The content of residual extractives in unbleached
(brownstock) pulp is low (1).
After separation from the pulp, the spent pulping liquor is evaporated to a high
concentration and then burned in a recovery boiler to recover energy and inorganic
chemicals, which are used to re-constitute fresh pulping liquor (1).
By comparison, lignin is solubilized in the sulfite process through sulfonation at elevated
temperatures. The pulping liquor contains sulfur dioxide and alkaline oxides (sodium,
magnesium, or calcium) (1). Ammonia is also used as a base chemical for sulfite pulping.
The lignin content of unbleached or brownstock pulp manufactured for the production of
bleached pulp is characterized by the Kappa number, or the permanganate number(K No.).
Kappa numbers for conventionally pulped unbleached softwood kraft pulp are generally in
NRJ-088
0327-01.nq 4-4

4.0 Wood Pulping and Chemical Recovery Systems
the range of 28 to 35, while those for hardwood kraft pulp may range from 14 to 18. For
softwood pulp, permanganate numbers are about one-third lower than corresponding Kappa
numbers, and for hardwood pulp, about 30% lower. Kappa numbers and permanganate
numbers for sulfite pulp are lower than for kraft pulp, reflecting the lower amount of lignin
present. Kappa numbers for brownstock pulp that is not bleached may range from less than
60 to more than 100, which is a reflection of the higher yield desired for linerboard and
other unbleached grades.
The distinguishing characteristics of the kraft and selected sulfite pulping processes are
presented in Table 4-1 and are discussed further below.
4.2 Pulping and Chemical Recovery Systems
4.2.1 Kraft and Soda Pulping
Figures 4-1 and 4-2 provide simplified schematic diagrams of the kraft pulping and chemical
recovery processes (8,9). Kraft pulping is economical because of the relatively efficient
recovery of pulping chemicals and the energy from the pulping liquor. The kraft recovery
system consists of the following major components:
• Collecting 'weak black liquor" washed from pulp (12-20% liquor solids) and
concentrating the liquor in multiple effect evaporators to "strong black liquor"
(typically 50% liquor solids);
• Oxidizing black liquor, if required, for odor control at mills equipped with
older design recovery boilers;
• Further concentrating strong black liquor in concentrators to "heavy black
liquor", typically >65% liquor solids;
NRJ-0sa
0327-01.nn 4-5

4.0 Wood Pulping and Chemical Recovery Systems
• Adding salt cake (Na,,SO4) to make up soda losses (for mills with extensive
TRS controls and sulfur recovery, most soda losses are made up with sodium
hydroxide);
• Incinerating heavy black liquor in a recovery furnace, where the released
energy is converted to steam and the inorganic chemicals are recovered in
molten form as smelt;
• Dissolving the smelt in a solution of weak wash from the causticizing circuit
to form "green liquor';
• Causticizing the green liquor with lime to form"white liquor" for return to the
digesters for pulping; and
• Reburning lime mud consisting of calcium carbonate (CaCO3) in a time kiln
to form lime (CaO) for reuse in the causticizing circuit.
Cited references should be consulted for more detailed information regarding kraft pulping
and recovery operations and the design of chemical process equipment. The processes for
soda pulping and chemical recovery are essentially the same as those for kraft pulping; the
main difference between these processes is that soda pulping does not involve the use of
sulfur compounds to facilitate delignification. Hence, the TRS-related odor problems
associated with kraft pulping do not occur. Soda pulping results in a lower yield and pulp
strength than the kraft process. Soda pulping is most often used to pulp hardwoods.
4.2.2 Sulfite Pulping
Schematic diagrams for typical ammonia, calcium, sodium, and magnesium base sulfite
pulping processes are presented as Figures 4-3 to 4-6, respectively (8,10). Mixtures of
sulfurous acid (H,SO,) and bisulfite ion (HSO ,_) are used to solubilize lignin. The lignin
is removed from the cellulose as salts of lignosulfonic acid, and the lignin molecular
structure remains largely intact. Sulfite pulping is performed over a wide range of pH.
"Acid sulfite" denotes pulping with an excess of free sulfurous acid at pH 1-2, while
vtu-M
0327-01.n� 4-6

4.0 Wood Pulping and Chemical Recovery Systems
"bisulfite" pulping is conducted under less acidic conditions in the range of pH 3-5 (8). The
use of digester blow pits, as shown on Figures 4-3 to 4-6, has been supplanted with the use
of digester blow tanks throughout the sulfite pulping industry to control digester blow gas
emissions.
The primary differences among the sulfite pulping methods lie in the base chemical used
for pulping and the extent of chemical recovery possible. Other than heat recovery from
calcium base weak liquors, there are no feasible means for calcium recovery from calcium
base liquors due to the formation of calcium sulfate. By-products or co-products (ligno-
sulfates, yeasts) can be derived from calcium base weak liquors through additional
processing, but calcium is not returned to the process from those operations. In most
ammonia base sulfite pulping, sulfur is recovered as SO2 from burning the weak liquor, but
ammonia is combusted and lost from the system (Figure 4-4).
The recovery systems for sodium base sulfite pulping are somewhat similar to kraft recovery
systems in that the weak liquor is concentrated with evaporators and combusted in recovery
boilers. A molten smelt is recovered and reconstituted, and sulfur is recovered as SO2 and
reused to prepare fresh cooking acid (Figure 4-5). Recovery of magnesium base liquors is
accomplished in specially designed recovery furnaces where, unlike kraft recovery boilers,
no smelt is produced. Rather, the combustion products are carried through the furnace and
recovered as magnesium oxide in cyclonic separators. The separators are followed by
gas/liquid contactors, where the remaining particulates and SO2 are scrubbed with a
magnesium hydroxide solution to regenerate the cooking liquor (Figure 4-6).
A number of commercial sulfite liquor recovery systems are available. Figure 4-7 presents
a summary of sulfite recovery systems currently in use (11).
VRt-098
0327-01.nq 4-7

4.0 Wood Pulping and Chemical Recovery Systems
4.2.3 Semi-Chemical Pulping
Figures 4-8 and 4-9 provide simplified schematic diagrams of a semi-chemical pulp mill
utilizing continuous digestion and a fluidized bed system for treatment of NSSC waste
liquor, respectively. Semi-chemical pulping liquors may range from sodium hydroxide alone
(cold soda) to alkaline sulfite liquors to mixtures of sodium hydroxide and sodium carbonate
to kraft green or white liquors. At semi-chemical mills co-located at kraft or sulfite pulp
mills, pulping liquors are processed by cross-recovery with kraft or sulfite liquors. Where
cross recovery is not feasible, the fluidized bed system illustrated in Figure 4-9, or a similar
system, is usually used.
nlu-0as
0327-01.n j 4-8

4.0 Wood Pulping and Chemical Recovery Systems
Table 4-1
Comparison of Kraft and Sulfite Pulping Processes
Process Characteristic Kraft Process Sulfite Process
Cellulosic Raw Material Almost any kind of wood, Any hardwood and non-resinous
soft or hard softwood; must be of good
color and free of certain hydroxy
phenolic compounds
Principal Reaction in Digester Hydrolysis of lignins to alcohols Sulfonation and solubilization of
and acids; mercaptans are ligain with bisulfite; hydrolytic
formed splitting of cellulose-lignin
Composition of Cooking Liquor 12.5 % solution NaOH, 7 % by weight SO,, of which 45
Na2S, and NaZCO, % is present as sulfurous acid,
and 25 % Ca, Na, NH, or
Mg(HS03)2
Cooking Conditions 2-5 hours at 340-350 OF and 6-12 hours at 257-320 OF and
100-135 psi 90-110 psi
Chemical Recovery Most of process is devoted to SO2 relief gas recovered; Mg or
recovery of cooking chemicals, Na liquor recovered after wood
with energy recovery from , digestion and washing.
burning organic matter dissolved Ammonia can be recovered in
in liquor- Chemical losses are some ammonia-base pulping
replenished with salt cake, systems.
Na2SO,.
Pulp Characteristics Brown color; difficult to bleach; Dull white color; easily
strong fibers; resistant to bleached; fibers weaker than
mechanical refining kraft fibers
NRr-osa
0327-ot.ail 4-9

4.0 Wood Pulping and Chemical Recovery Systems
Table 4-1
(Continued)
Process Characteristic Kraft Process Sulfite Process
Typical Paper Products Strong brown bag and wrapping; Book paper, bread wrap,
multiwall bags; gumming paper; sanitary tissue
building paper; white papers
from bleached krah; paperboard
for cartons, containers, and
corrugated board
Sources: EPA, 1982 (5); Green and Hough, 1992 (9); Ingruber, et al., 1985 (11).
NRJ-088
0327-01.nq 4-10

4.0 Wood Pulping and Chemical Recovery Systems
Figure 4-1
Kraft Process
Simplified Schematic Diagram
CYs
WM«
O,.«« 771 WM4l Quv lwn. .�w
C T-z
W,31yr
WMY llpp
�a+P
8b Tank
Un1,wkb
T1licwwr,f
W,31�«3 GM3
PULP si,w« llme ume
— Kiln
Wo,w Bloch _
U�5br", Slw�
W~
Evyp,ew� Ca3rtiM,C CrM1l Lkp O-w IIIa�9, a4
C4M,ww,13 ct ow Wally
Bemv,nnq SnrN DhMw9 WaY
finxc� law w
Source: SmOok, 1989 (8)
NRt-088
0327-0t.nd 4-11

4.0 Wood Pulping and Chemical Recovery Systems
Figure 4-2
Kraft Pulping and Chemical Recovery
Simplified Schematic Diagram
Aso �ae1P
0
0
e a
0
F
ti
6
s\as Fkm
Gas
Cookwn E�sA
l+vua
Hecn�ery
Baler
ayes.
sus\
G
Wlvle Co�roarsa
cwar C Blsm lglar
_ IanI Sa
Kr pp
Predplabs
MUe
Waster
Smell
Slaker
Green
Up"
CWUNN,
(- Dregs
Waeter
Source: Green and Hough, 1992 (9)
NRJ-088
0327-01.nd 4-12

4.0 Wood Pulping and Chemical Recovery Systems
Figure 4-3
Ammonia Base Sulfite Pulping
Simplified Schematic Diagram
t
BURNER NHAOH
+I COMBUSTION CHAMBER ABSORPTION TOWER
1 COOLER STORAGE SCRUBBER
FAN LOW PRESSURE ACCUM.
I
BURNER GAS - HIGH PRESSURE ACCUM
COOKING ACID
DIGESTER
—+ RELIEF
BLOW PIT SPENT LIQUOR
SULFITE PULP
Source: Libby, 1962 (10)
NRJ-088
0327-01.ncj 4-13

4.0 Wood Pulping and Chemical Recovery Systems
Figure 4-4
Calcium Base Sulfite Pulping
Simplified Schematic Diagram
WATER PURIFICATION
BOILER STEAM STEAM
FUEL FURNACE STACK GAS
RCUEF
LIMESTONE
SPENT
-� GAS �
0 0
< W SPENT V
SuI.iUR-�-
T GAS BLOW
O u OF w G GASES
MELTER GAS COOLER J fK0 LOW HIGH
PRESSURE PRESSURE SPENT
Lt= �� ACCU M. ACCUM. BPLOW AND
AIR BURNER FAN IO IT WASH
LIQUORS
COMBUSTI N
CHAMBER
-- -- PULP
WATER
WASHERS KNOTTER3 RIFFLERS SCREENS UNBLEACHED
EPULP
WASH WATER TAILINGS PRODUCT
Source: Libby, 1962 (10)
NR-M
Dan-Dt.nd 4-14

4.0 Wood Pulping and Chemical Recovery Systems
Figure 4-5
Sodium Base Sulfite Pulping
Simplified Schematic Diagram
WGDO CMIIS WATER NR Y ^IMNP SVLEuw A EYE BENT LIQ 0
OWER
ACID
I ACID STORAG[ EVARORATORS CONOEMBATf.
XROMp
1101"IE STEAK
LOW RRESSERE ACC ruw"ACE
MIGN racswaE ACC. N S SPELT SOI EL-E GK
2
'- CgORING ACID I OISSOLVEII
STE-u OIGESTER REVEE CARBONATION TOWER II _
iLUE GA3
ENt
BUT+ GN GI. IT vOVM St-LIFTING TOYER
I
SULIM PE
Source: Libby, 1962 (10)
NRf.oas
0327-01.nq 4-15

4.0 Wood Pulping and Chemical Recovery Systems
Figure 4-6
Magnesium Base Sulfite Pulping
Simplified Schematic Diagram
WOOD CHIPS MAGNESIA MAKEUP WATER SULFUR MAKEUP SPENT LIQUOR
GAS M90
ABSORPTION TOWER EVAPORATORS CONDENSATE
STORAGE SCRUBBER
BOILER I STEAM
LOW PRESSURE ACCUM. FURNACE
N.GN PRESSURE ACCU,. CYCLONE
I
cns Mgo
COOKING ACID
STEAM DIGESTER RELIEF
BLOW GAS BLOW PIT .SPENT LIQUOR
SULFITE PULP
Source: Libby, 1962 (10)
N RJ-oss
0327-01.nIj 4-16

4.0 Wood Pulping and Chemical Recovery Systems
Figure 4-7
Sulfite Recovery Systems Currently in Use
Dispose
Incinerate Burn--. Calcium Base Evaporation
Spent Sulfite Evaporate Pyrolyze and Burning
Liquor Wet Combinalion Dry
Lignin Chemicals L gnosol
Calcium Base Recover by-products Yeast(protein)
Alcohol
Lime Precipitate
Thermally Precipitate
Treat Biologically
Evaporate and Burn to Babcock 6 Wilcox, LenLng, Flakt
Magnesium Base - Magnesium Oxide and so,—�
Ion Exchange Copeland — Fluid Bed
Incinerate
Evaporate and Dry Ir--� No Recovery
Evaporate and Burn Recovery SO, Ammonium Base
Recover NH3 and SO, Evaporation and
Ammonium Base Burning
Ion Exchange Na Recover NH,
Base Exchange Mg—+ Evaporate and Burn, and SO,
Pyrolyze LLLL----.... Ca
Incinerate I with AI(OH), - Sonoco
Evaporate and Burn Under y Flwd Bed Copeland 8 Dorrover
Oxidizing Conditions -0
Wet Combustion Zimmerman
Electrolyze
Ion Exchange
Sodium Base
Evaporate and Pyrotyze - SCA
Precipitate Lignin Chemicals ->• Ont. Paper
Recover by-products Yeast(Protein)
Treat biologically Alcohol Onl. Paper
Evaporate and Burn Under Reducing Conditions
Oxidize directly to sulfite Ebara
Separate sulfide
Leach and oxidize to sulfite RAS
Strip as H,S with
Smelt NaHCO, — Rauma Tampeua
CO,, NaHSO, Slora
Na,S+Na,CO, Organic acid
Acid exchange resin
Isolate sodium carbonate
F-_ Leach and can trifu RAS
Crystallize Tampella Rauma
Source: Ingruber, et al., 1985 (11)
NRJ-088
0327-01.nr; 4-17

4.0 Wood Pulping and Chemical Recovery Systems
Figure 4-8
Semi-Chemical Pulping Mill Utilizing Continuous Digestion
Simplified Schematic Diagram
Cnp..uznnq
wosners
O"Ps Sieom
Impregn0hon
cook,nq
liquid
Sieomm9 0igesler i
+essel _-
Reliners =_ Pop
stornoroge
I Rehners
Sltom
Source: Smook, 1989 (8)
NRJ 088
0327-0I.nq 4-18

4.0 Wood Pulping and Chemical Recovery Systems
Figure 4-9
Fluidized Bed System For Treatment of NSSC Waste Liquor
Simplified Schematic Diagram
WEAK LIQUOR WASTE ATMOSPHERE FROM MILL
VENT
CONCENTRATED
LIQUOR STORAGE
ua wuoa
WEAK
[:S,OTAKLIQUOR - LIQUOR
ORAGEWETa SCRUBBER
FLU OOIZED
BED CYCLONE
*UIDIZING
TO
WEAK
TRIPLE E FECT LIQUOR
EVAPORATORS DUST STORAGE
RETURN
SOLID PRODUCT
AIR
Source: Smook, 1989 (8)
NTU-M
0327-01.nq 4-19

5.0 COMPOSITION AND TOXICITY OF PULPING LIQUORS
5.1 Kraft Mill Black Liquor
The chemical composition of black liquor is of particular interest because of the adverse
impact pulping liquors can have on biological wastewater treatment facilities, the potential
for discharge of chemicals toxic to aquatic life, and the emission of TRS and HAPs to the
air.
Weak black liquor recovered from brownstock pulp washing may have a liquor solids
content ranging from about 12% to as high as 20%, depending on the brownstock washing
systems used and the mill's operating practice. The typical elemental analysis for black
liquor from a bleached kraft mill with a pulp mix of 80/20 softwood/hardwood and a higher
heating value (HHV) of 6,030 British thermal units per pound (BTU/lb) of liquor solids is
as follows (8):
Constituent Percent of Black Liquor Solids
Sodium (Na) 19.2
Sulfur (S) 4.8
Carbon (C) 35.2
Hydrogen (H) 3.6
Oxygen (0) 35.2
Potassium (K) 1.0
Chloride (Cl) 0.1
Inerts 0.2
Liquors that have greater heating values (up to 6,500 BTU/lb of liquor solids) will tend to
have a larger fraction of carbon, and less oxygen and sodium; the opposite is true of liquors
that have lower heating values (9).
N RJ-0as
0327-01.nq 5-1

5.0 Composition and Toxicity of Pulping Liquors
The primary inorganic constituents in black liquor include:
• Sodium Hydroxide (NaOH);
• Sodium Sulfide (Na=S);
• Sodium Carbonate (Na2CO3);
• Sodium Sulfate (NaZSO,);
• Sodium Thiosulfate (NazS203); and
• Sodium Chloride (NaCI).
These compounds originate from the white liquor used for pulping, although small amounts
may also be introduced with the wood (9). Table 5-1 presents a summary of the inorganic
content of black liquors measured at 27 kraft mills (9). Dissolved wood substances in black
liquors consist of four types of substances: (1) ligneous materials (polyaromatic in
character); (2)saccharinic acids (degraded carbohydrates); (3)low-molecular-weight organic
acids; and (4) extractives (resins and fatty acids) (9). The organic constituents are combined
chemically with sodium hydroxide in the form of sodium salts. Considerable differences in
liquor quality from pulpwoods are reported, particularly between softwoods and hardwoods
(9). Typical ranges of black liquor solids are listed below:
Constituent Percent of Black Liquor Solids
Alkali Lignin 30-45
Hydroxy Acids 25-35
Extractives 3-5
Acetic Acid 5
Formic Acid 3
Methanol 1
Sulfur (S) 3-5
Sodium (Na) 17-20
xr-0ss
0327-01.nq 5-2

5.0 Composition and Toxicity of Pulping Liquors
Table 5-2 presents supplemental detailed data for black liquor components for four pine
liquors and one spruce liquor (9).
5.2 Sulfite Pulping Liquors (Red Liquors)
Table 5-3 presents the compositions of one calcium base and two magnesium base sulfite
pulping liquors, and Table 5-4 presents the compositions of four ammonia base and twelve
sodium base sulfite pulping liquors (11). The ammonia base liquors have higher levels of
organic materials, as measured by BOD3, COD, and dissolved organic compounds;are about
an order of magnitude more toxic than calcium base and magnesium base liquors; and are
about five times more toxic than sodium base liquors. The toxicity emission factors (TEFs)
presented in Tables 5-3 and 5-4 are based on static 96-hour bioassays and are factored to
the volume of liquor production. The presence of ammonia compounds in ammonia base
liquor is the likely cause of the higher toxicity.
5.3 Semi-Chemical Pulping Liquors
The compositions of typical NSSC fresh and spent pulping liquors are presented in Tables
5-5 and 5-6, respectively (11).
5.4 Toxicity of Pulping Liquors
The toxicity of wood pulping liquors has been extensively studied for many years. The
National Council of the Paper Industry for Air and Stream Improvement, Inc. (NCASI,
formerly the National Council of the Pulp, Paper and Paperboard Industries for Stream
Improvement) conducted studies with the Institute of Paper Chemistry in the 1940s and
1950s to determine the toxicity of components of kraft mill pulping wastes (12,13,14).
NCASI reported minimum lethal concentrations of several compounds for certain species
NF-J-M
0327-Ot.nd 5-3

5.0 Composition and Toxicity of Pulping Liquors
of Daphnia and Pimephales promelas (fathead minnows). These concentrations are
summarized in Table 5-7.
The results presented in Table 5-7 show that hydrogen sulfide, methyl mercaptan, crude
sulfate soap, and sodium salts of fatty and resins acids are among the components of black
liquor that are toxic to Daphnia and freshwater minnows. Minimum lethal concentrations
in the low parts per million (ppm) were found for these compounds.
McKee and Wolf also summarized compilations of toxicity data for components of sulfate
(kraft) liquors to fish (15). These data (some of which are included in Table 5-7) are
presented in Table 5-8.
More recent studies of in-mill toxicity at a northern Ontario (Canada) bleached kraft mill
resulted in the following recommendations to reduce effluent toxicity (in priority ranking)
(16):
• Improve black liquor spill control system;
• Provide total countercurrent recycle of brownstock washers;
• Dedicate No. 1 Mill to hardwood production;
• Improve condensate system;
• Improve digester plant;
• Eliminate liquor carryover to blow heat condensate;
• Upgrade No. 1 Mill evaporators; and
• Improve soap recovery.
Nlu-0sa
0327-01.nry 5-4

5.0 Composition and Toxicity of Pulping Liquors
At this mill, the pulp mill sewer was found to contribute 55% of the effluent toxic loading,
while the combined condensate and (bleach plant) acid sewer contributed 2517o and 20%,
respectively. Of the eight recommendations to reduce effluent toxicity, the two with the
highest priority (and five of the eight recommendations), were directed at reducing the
amount of black liquor lost from the processes. Improvements to the black liquor spill
control system were cited as the measures that would have the greatest impact on reducing
effluent toxicity.
Toxic impacts to the aquatic environment by compounds associated with kraft pulping
liquors have also been reported. A large spill of black liquor from a kraft mill resulted in
"massive fish mortalities" at the time of the spill. It was estimated that natural
recolonization of the river by native fish would take several years (17). Sublethal toxic
effects in rainbow trout have been attributed to the accumulation of dehydroabietic acid
discharged from a kraft mill (18).
At a large southern United States bleached kraft paperboard mill, the process wastewater
effluent is discharged to a local POTW; this wastewater comprises more than 95% of the
combined industrial and municipal wastewater volume treated at the POTW (19). The
POTW provides biological treatment with an aerated stabilization basin similar to those
installed at many kraft mills. A portion of the pulp produced at the mill is bleached. Prior
to 1990-1991, the mill had essentially no facilities for the control and collection of black
pulping liquor spills and leaks. POTW discharge monitoring records show the fully treated
effluent exhibited consistent chronic toxicity to Daphnia from April 1988 until June 1991.
During 1989 and early 1990, when the mill was undergoing extensive upgrading, POTW
operating records document over 100 incidents of black pulping liquor losses from the mill.
During that time, there were numerous violations of the POTW NPDES permit effluent
limitations for TSS, BOD5, and tonicity effluent limitations (19). The NPDES permit for the
Nar-0ss
0327-01.nq 5-5

5.0 Composition and Tonicity of Pulping Liquo
POTW required acute and chronic toxicity testing using Daphnia and fathead minnows. The
permit contained a limitation of no acute toxicity in whole effluent and a chronic toxicity
limit No Observable Effect Level (NOEL) of 66%.
NPDES permit operating data for the period of December 1988 through December 1992
showed intermittent acute toxicity of the effluent to Daphnia from mid-1989 through early
1990, and consistent chronic toxicity to Daphnia until mid-1991, when most of the spent
pulping liquor spill prevention and control facilities were installed at the mill (19).
The mill underwent a major upgrade during much of 1989 and early 1990. A series of
construction problems resulted in heavier-than-normal black liquor losses to the sewer,
which hampered POTW operations. POTW performance with respect to conventional
pollutant discharges improved in 1992. Improvements in effluent toxicity and POTW
operations after 1991 were attributed primarily to effective spent pulping liquor
management, spill prevention, and control at the mill (see Section 9.4).
5.5 Toxic Pollutants Found in Spent Pulping Liquors
EPA collected samples of spent pulping liquors from four kraft mills and one sulfite mill for
analysis of toxic wastewater pollutants and volatile organic compounds, including HAPs.
The results of these analyses are presented in Table 5-9. These data show that phenol was
detected in samples of hardwood and softwood kraft black liquor at concentrations ranging
from 1,200 micrograms per liter (µg/L) to more than 50,000 µg/L, and in sulfite red liquor
at 882 µg/L. Zinc was found in the one softwood black liquor sample analyzed for metals
at nearly 15 µg/kg (micrograms per kilogram, or parts per billion).
Nx1-0sa
0327-01.n[ 5-6

5.0 Composition and Toxicity of Pulping Liquors
Table 5-1
Inorganic Content of Black Liquors
(Weight Percent, Dry Solids Basis)
Constituent Average Minimum Maximum
Sodium Carbonate 8.7 6.6 12.3
Sodium Sulfate 3.2 0.9 8.3
Active Alkali as Na,O 6.0 3.9 8.6
Sodium 18.7 17.2 20.5
Potassium 1.4 0.4 2.7
Sulfur 3.8 2.6 6.2
Sulfated Ash 62.1 57.3 69.2
Source: Green and Hough, 1992 (9)
NRJ-088
0327-01.nq 5-7

5.0 Composition and Toxicity of Pulping Liquors
Table 5-2
Components in Black Liquors
(Weight Percent, Dry Solids Basis)
Pine Pine Pine Pine Spruce
Component Liquor Liquor Liquor Liquor Liquor
Lignin 28.9 30.7 31.1 42 41
Hemicellulose and 1.14 0.11 1.3
Sugars
Extractives 6.69 2.53 5.7 3
Saccharinic Acids 18.8 28
Acetic Acid 3.52 2.08 5.2 3.83 5
Formic Acid 4.48 2.7 3.1 3.37 3
Other Organic Acids 5.5 2.22
Methanol 1
Unknown Organic 19.0 29.5 5.8 25.6
Compounds
Inorganic Salts 18.6 18.5 20.3 25.6
Organically Combined 10.1 10.3 8.7
Sodium
Unknown Inorganic 2.08 1.35
Compounds
Sulfur 3
Sodium 16
Total 100 100 100 100 100
Source: Green and Hough, 1992 (9)
NRJ-088
0327-01.nq 5-8

5.0 Composition and Toxicity of Pulping Liquors
Table 5-3
Composition of Calcium Base and Magnesium Base
Sulfite Pulping Liquors
Characteristic Calcium Base Magnesium Base
Mill 3 Min 1 Mill 4B Average
Pulp Yield (%) 46 54 45 50
Liquor Volume"' 9.28 6.56 5.61 6.08
(m'/ODT)
pH 5.3 3.4 3.3
TOC (kg/ODT) NV NI" NTH Nf'A
BOD (kg/ODT) 357 169 275 222
COD (kg/ODT) 1,533 807 1,144 975
Dissolved Organics 1,043 651 913 782
(kg/ODT)
Dissolved Inorganics 250 173 79 126
(kg/ODT)
LTV Lignin (kg/ODT) 800 469 533 501
Total Sugars 264 94 165 129
(kg/ODT)
Reduced Sugars 238 32 180 106
(kg/ODT)
TEFa) 422 316 NTH
Notes: (1) Estimated liquor volume a few minutes before 'blow.'
(2) NT- Not Tested.
(3) TEF - Toxicity Emission Factor
(100%196hr LC, %)x Liquor Volume (m'/ODT pulp)
(TEF approach in Table 5-3 was not developed by EPA.)
Source: Ingruber, et al., 1985 (11)
NRJ-088
0327-01.nn 5-9

5.0 Composition and Toxicity of Pulping Liquors
Table 5-4
Composition of Ammonia Base and Sodium Base
Sulfite Pulping Liquors
Ammonia Bue(4 KAU) Sadism Bun(12 M Us)
Characteristic Avenge Minimum Maxmi m Avenge Minim= Maximum
Pulp Yield(%) 42.5 41 45 62 50 80
Liquor Vor' 9.46 9.11 9.73 7.10 4.92 10.67
(m'/ODT)
pH — 1.5 3.3 — 2.1 4.8
TOC(tg/ODT7^ NN' NTn Nrm 697 1 322 1,652
BOD(:g/OD7) 1 413 319 464 233 151 371
COD(kg/ODT) - 1,728 1,553 1.972 938 476 1,757
Dissolved 1,223 1,167 1,283 595 188 1,178
Organics
(kg/OD7)
Dissolved 12.5 7.0 20 226 95 348
Inorganics
(kg/OD7)
W Lignin 892 822 1.009 410 202 $53
(kg/OD1)
ToW Sugar 288 210 329 137 52 278
(kg/ODT)
Reduced 212 160 257 74 11 219
Sugar
(kg/ODT)"
TEF" 3,663 3,313 4,378 114 423 1,208
Notes: (1) Estimated liquor volume a few minutes before 'blow.
(2) NT- Not Tested.
(3) TEF - Toxicity Emission Factor
(100%196hr LC,, %)x Liquor Volume (m'/ODT pulp)
(TEF approach in Table 5-4 was not developed by EPA.)
(4) Results for TOC and Reduced Sugars for sodium base liquor are based on data for 8
mills and 11 mills, respectively. Results for all other parameters are based on data for
12 mills.
Source: Ingruber, et al., 1985 (11)
IVR3-08a
0327-01.nq 5-10

5.0 Composition and Toxicity of Pulping Liquors
Table 5-5
Composition of Typical Fresh NSSC Pulping Liquors
Concentration
Chemical Compound (grams/liter as chemical)
Sodium Sulfite 133
Sodium Hydroxide 58
Sodium Sulfate 3.2
Sodium Thiosulfate < 0.1
Sodium Sulfide < 0.1
Total Sodium 53.0
Total Sulfur 35.1
Source: Ingruber, et al., 1985 (11)
N RJ-088
0327-ot.nn 5-11

5.0 Composition and Toxicity of Pulping Liquors
Table 5-6
Composition of Typical Spent NSSC Pulping Liquors
Characteristic Average Minimum Maximum
pH 6.5 8.5
Total Solids (%) 12 8 22
Volatile Solids (%) 47.9 43 52
(percent of Total Solids)
BODS (mg/1) 25,000 16,000 50,000
Acetate (mg/1) 18,000 12,000 20,000
Wood Sugars (mg/1) 7,000 5,000 10,000
(mostly pentoses)
Lignin (mg/1) 45,000 25,000 85,000
Oxygen Consumption (mg/1)
From KMnO, 65,000 55,000 142,000
From Ag-catalyzed 100,000 83,000 235,000
dichromate
Source: NCASI, Technical Bulletin 83
:.Rw88
0327-01.np 5-12

5.0 Composition and Toxicity of Pulping Liquors
Table 5-7
Minimum Lethal Concentrations to Daphnia and Fathead Minnows
of Components of Kraft Pulp Mill Wastewaters
Minimum Lethal Concentration
(parts per million)
Fathead
Compound Daphnia Minnows
Sodium Hydroxide 100 100
Sodium Sulfide 10 3.0
Sodium Sulfate 5,000 1,000
Methyl Mercaptan 1.0 0.5
Sodium Sulfite 300 --
Hydrogen Sulfide 1.0 1.0
Sodium Carbonate 300 250
Sodium Sulfate 5000 100
Crude Sulfate Soap 5.0 - 10.0 5.0
Sodium Salts of Fatty Acid Fraction 1.0 5.0
of Sulfate Soap
Sodium Salts of Resin Acid Fraction 3.0 1.0
of Sulfate Soap
Source: NCASI, 1947 (12)
N4RI-088
0327-0I.an 5-13

5.0 Composition and Toxicity of Pulping Liquors
Table 5-S
Critical Concentrations (Minimum Lethal Doses) to Fish
of Components of Sulfate (Kraft) Liquors
Critical Concentration
Component (milligrams per liter)
Sodium Hydroxide 100.0
Sodium Sulfide 3
Methyl Mercaptan 05
Hydrogen Sulfide 1.0
Formaldehyde 50
Crude Sulfate Soap 5.0
Unsaponified Fraction of Sulfate Soap 6.0
Sodium Salts of,Saporiifiable Fraction 3.0
of Sulfate Soap
Sodium Salts of Fatty Acids 5.0
Sodium Salts of Resin Acids 1.0
Sodium Oleates 5.0
Sodium Linoleate 10.0
Sodium Salts of Abietic Acid 3.0
Phytosterol 3.0
Sodium Thiosulfate 5.0
Sodium Sulfate 100
Sodium Chloride u00
Sodium Hydrogen Sulfide 0.5
Sodium Sulfide (as Sulfide) 1.2
Source: McKee and Wolf, 1963 (15)
NRJ-0sa
0329-01.nry 5-14

5.0 Composition and Toxicity of Pulping Liquors
Table 5-9
Toxic Wastewater Pollutants and Hazardous Air Pollutants
Found in Spent Pulping Liquors
Sulfite
Red
Kraft Mill Black Liquors Liquors
Regulatory Hardwood Softwood Softwood Softwood Softwood
Pollutant Status (µg/L) (µg/L) (µg/kg) (µg/L) (µg/L)
Acetone - 9,189 3,879 15,040 ND (500) 2,325
Benzoic Acid - 4,660 13,985 ND (5000) 5,784 8,999
Benzyl Alcohol - ND (100) 885 ND (1000) 1,374 ND (53)
Benzanthrone - ND (500) ND (500) 7,509 ND (500) ND (10)
Carbon Disulfide HAP 149 892 114 ND (100) ND (10)
p-Cresol HAP ND (100) ND (1000) ND (1000) ND (100) 100
p-Cymene HAP ND (100) ND (100) ND (1000) 1,141 418
p-Dioxane HAP 890 ND (100) ND (60) ND (100) ND (10)
Hexanoic Acid ND (100) ND (1000) ND (1000) ND (100) 1,633
Methyl Ethyl HAP 2,407 1,247 2,660 4,027 ND (50)
Ketone
Phenol HAP, PP 1,233 14,985 52,296 1,990 882
a-Terpineol 322 827 ND (1000) 4,933 65
1,3,5-Trithiane ND (500) 193,214 ND (1000) 73,305 ND (263)
Manganese NA NA NA 76.40* NA
Sodium NA NA NA 138,910 * NA
Zinc PP NA NA NA 14.87* NA
Notes: (1) NAP - Hazardous Air Pollutant
(2) PP - Priority Pollutant
(3) ND - Not Detected (at reported detection limit)
(4) NA - Not Analyzed
(5) * - Units are µglkg (sample contained 6.6 % solids)
Source: EPA Project File: Pulp, Paper and Paperboard Point Source Category
NR1-038
0327-01.nq 5-15

6.0 SOURCES OF SPENT PULPING LIQUOR LOSSES
6.1 Kraft and Soda Mills
Losses of black liquor from kraft and soda pulping and chemical recovery processes arise
from "normal' process operations, including maintenance practices; planned startups and
shutdowns of evaporators, concentrators, and recovery boilers; grade changes; other
intentional liquor diversions; and losses from screen rooms, brownstock washers, and
deckers. Unintentional losses result from fiber and liquor spills, equipment leaks, tank
overfillings, and process upsets.
The main difference between kraft and soda pulping is that sulfur compounds are not added
in soda pulping. Soda pulping is less efficient than kraft pulping, which results in more
black liquor production per ton of pulp and correspondingly larger recovery systems at soda
mills than at equivalent-sized kraft pulp mills. Because of the absence of sulfur compounds,
soda mills are not characterized by strong TRS odors and thus do not have the extensive
TRS control systems common to kraft mills. Otherwise, the pulping and chemical recovery
systems are similar for the two processes. Based on evaluations conducted at several kraft
mills and at one soda mill, EPA identified the following significant sources of black liquor
losses from normal process operations:
• Leaks from seals on brownstock washers;
• Leaks from seals on pumps and valves in black liquor service;
• Intentional liquor diversions during shutdowns, startups, grade changes, and
equipment maintenance;
• Sewered evaporator boil-out solutions;
• Decker losses at older mills with open screen rooms; and
• Losses from knotters and screens at mills without fiber and liquor recovery
systems for those sources.
vx.wss
0327-01.nq 6-1

6.0 Sources of Spent Pulping Liquor Losses
Process upsets, equipment breakdowns,tank overfillings,construction activities,and operator
errors were identified as the most common sources of unintentional black liquor and
causticizing area sewer losses.
6.2 Sulfite Mills and Semi-Chemical Mills
Although the pulping systems at sulfite and semi-chemical mills are based on different
process chemistry and different chemical recovery facilities, spent pulping liquor losses from
normal process operations and unintentional losses at these mills arise from many of the
same types of sources as at kraft and soda mills.
6.3 Summary of Reported Pulpine Liauor Spills
Through its Emergency Response Notification System (ERNS), EPA maintains a database
of reported spills of oil and other materials. The ERNS Standard Report Database was
searched for the period January 1988 to March 1993 using key words relating to pulping
liquors (e.g., black liquor, green liquor, white liquor, red liquor, pulping liquor) to
determine the reported number of pulping liquor spills, the volume of spilled material, the
affected media, and the reported causes of the spills (20). The ERNS Standard Report
Database does not contain information about environmental impacts caused by spills.
The reporting of spills by the industry does not appear to be uniform. Some of the reported
spills were minor in nature and were confined to the mills. On the other hand, relatively
large sewer losses of black liquor observed at a number of mills over the past few years do
not appear in the ERNS Standard Report Database. Hence, the information obtained from
the ERNS Standard Report Database is not considered a comprehensive measure of pulping
liquor losses across the industry, especially with regard to spills and losses confined to mills
and directed to wastewater treatment systems. Despite these limitations, the information
NRJ-098
0327-01.n� 6-2

6.0 Sources of Spent Pulping Liquor Losses
regarding the causes of the spills is informative and useful for planning new and upgraded
pulping liquor spill, prevention, and control programs.
Table 6-1 presents a summary of the reported pulping liquor spills. Of the 82 reported
spills, 1 was a red liquor spill from a sulfite mill, 59 were black liquor spills, 10 were green
liquor spills, and 12 were white liquor spills. About 25% of the smaller spills (less than
1,000 gallons) reached mill sewer systems or receiving waters. About 50% of the larger
spills (greater than 1,000 gallons) were spills to water, and most of these spills reached
receiving waters. The, extent to which these spills passed through wastewater treatment
systems was not discernable from the available ERNS reports. More than 40% of the spills
of unknown volume reached receiving waters. The two largest reported spills were a 96,000-
gallon black liquor spill from a pulp mill located in Maine and a 90,000-gallon green liquor
spill from a Florida pulp mill. Eighteen spills were caused during loading, unloading, and
transportation operations.
The reported causes of pulping liquor spills were as follows:
• Mechanical Failure (45%);
• Human Error (20%);
• Tank Overfilling (16%);
• Deliberate (4%);
• Weather (1%);
• Power Failure (1%); and
• Unknown (13%).
Many of the mechanical problems involved malfunctioning valves, flanges, and pumps;
pipeline corrosion; and a lack of preventive maintenance. In addition to tank overfillings,
which resulted primarily from human error, liquor losses attributed to human error also
included improper closure of valves and vehicular accidents inside and outside the pulp
mills.
NFU-08a
0327-01.nq 6-3

6.0 Sources of Spent Pulping Liquor Losses
6.4 Untreated Wastewater Loadines for Kraft Mill
Of the untreated BOD5 wastewater loading at a kraft pulp mill with open screen rooms,
about one-third can be attributed to decker filtrate; one-third to one-half can be attributed
to intermittent, uncontrolled losses; and the balance can be attributed to sewered
contaminated condensates (2). Much of the BODS loading from decker filtrate and
intermittent, uncontrolled losses is attributable to black liquor (2).
Spent pulping liquor losses to .the pulp after brownstock washing (i.e., soda losses
attributable to residual liquor remaining in the brownstock pulp after washing) are not
included in this report. The reduction of brownstock washing losses is an important aspect
of process optimization, as well as a pollution prevention technique, particularly at bleached
kraft mills, because the increased formation of chlorinated organics and higher sewer
loadings of COD, AOX, and BOD5 have been attributed to poor brownstock washing.
Improved brownstock washing is included as an integral part of each model BAT, NSPS,
PSES, and PSNS process technology train considered by EPA for bleached kraft and soda
mills.
Table 6-2 provides typical untreated wastewater loadings from an ideal bleached kraft mill
(2). These data indicate that pulping and chemical recovery processes account for nearly
15 kilograms (kg) BODs per air-dried metric ton (ADMT) of pulp, or nearly 38% of the
total raw waste loading. For an unbleached kraft mill, the raw waste loading from pulping
and chemical recovery processes would approach 60% of the total mill loading. Nearly all
of the BODS loading from pulping and chemical recovery operations originates in foul
condensates and losses of spent pulping liquor.
NCASI estimates that the BODs loading to the recovery circuit from weak black liquor is
360 kg/ADMT of pulp (21). NCASI also advises kraft mill operators to assume 2% liquor
Nlu-088
03?7-0l.nq 6-4

6.0 Sources of Spent Pulping Liquor Losses
losses in estimating emissions for Superfund Amendments and Reauthorization Act (SARA)
Section 313 reporting purposes (22). These estimates imply that BOD5 raw wastewater
loadings from "normal' liquor losses are slightly more than 7 kg/ADMT. The practical
maximum reduction in BOD5 raw wastewater loadings that can be attained from spill
prevention is reported at 5 kg/ADMT, and the estimated BOD5 raw waste loading from a
state-of-the-art kraft mill is reported at 5 kg/ADMT for pulping and chemical recovery
operations (2).
6.5 Untreated Wastewater Loadings for Sulfite Milt
Table 6-3 presents approximate untreated wastewater loadings normalized to pulp
production for two sulfite mills. At both mills, most of the BODS wastewater loading is
associated with pulping and chemical recovery operations. For the calcium base mill, the
relatively high untreated BOD5 wastewater loadings result from the external (off-site)
recovery of lignin chemicals, in which wastewaters and condensates are processed at an
adjacent facility and returned to the mill for treatment and discharge.
utu-0ss
0327-01.nd 6-5

6.0 Sources of Spent Pulping Liquor Losses
Table 6-1
Summary of Reported Pulping Liquor Spills
EPA Emergency Response Notification System (ERNS) Database
(January 1988 - March 1993)
Number of Reported Spills
Media Affected
Volume Spilled Water Receiving
(gallons) Total Land (All Types) Waters
< 100 21 18 3 3
100 to < 1,000 12 7 5 5
1,000 to < 5,000 15 9 6 5
5,000 to < 10,000 -- -- --
10,000 to < 50,000 5 1 4 3
> 50,000 2 1 1 1
Unknown Volume 27 11 16 11
Total 82 47 35 28
Source: EPA ERNS, 1993 (20)
N RJ-M
0327-01.nq 6-6

6.0 Sources of Spent Pulping Liquor Losses
Table 6-2
Typical Untreated Wastewater Loadings From an
Ideal Bleached Kraft Mill
FlowM(100)
BODS
Process (m3/ADMT (%)) %)) (kg/ADMT (%}}Wood Yard 0.7 ( 4.8) .2) 0.8 ( 2.3)Pulping 21 (14.3) 0.0) 9.4 (26.1)Recovery 17 (11.9) .5) 4.1 (11.4)Bleaching 48 (33.3) .0) 12.7 (35.4)Paper Manufacturing 52 (35.7) .3) 8.9 (24.6)TOTAL 138.7 (100) 0) 35.9 (100)
Source: Springer, 1986 (2)
NN P J-088
0327-01.nq 6-7

6.0 Sources of Spent Pulping Liquor Losse.
Table 6-3
Examples of Untreated Wastewater Loadings for Two Sulfite Mills
Flow TSS BODS
Process (m'/ADMT(%)) (kg/ADMT (%)) (kg/ADMT (%))
Mill E - Calcium
Acid Making, 32.9 (57) 69.1 (38)
Pulping, Washing,
Bleaching
External Recovery -- 77.0 (42)
Wet Air Oxidation 2.5 (4) 185 (10)
Paper Machines 22.2 (39) 17.7 (10)
TOTAL 57.6 (100) 1823 (100)
Mill F - Magnesium
Pulping and 67 (47) 34.1 (41) 71.2 (80)
Recovery, Washing,
Bleach Plant
Paper Machines 76 (53) 48.1 (59) 18.1 (20)
TOTAL 143 (100) 82.2 (100) 893 (100)
Source: EPA Project Files: Pulp, Paper and Paperboard Effluent Limitations Guidelines
V RJ-088
0327-01.nq 6-8

7.0 SPENT PULPING LIQUOR MANAGEMENT, SPILL PREVENTION, AND
CONTROL: CURRENT INDUSTRY PRACTICE
7.1 Kraft and Soda Mills
Current industry practice with regard to spent pulping liquor management, spill prevention,
and control was evaluated through, the performance of numerous mill visits and an
evaluation of the results of a NCASI BMP survey of kraft and sulfite mills (23). Site visits
were conducted at more than 30 kraft mills, 5 sulfite mills, and 1 soda mill. These mills
were selected for site visits based on age, size, discharge status (direct and indirect), and
pulping practice (kraft mill, soda mill, ammonia base, magnesium base, and calcium base
sulfite). The kraft and soda mills ranged from mills constructed in the early 1900s to
relatively new greenfield mills constructed in the mid to late 1980s. The age of the sulfite
mills ranged from 70 to 90 years. The NCASI BMP survey elicited responses from more
than 60 mills; site visits were conducted at many of these mills.
Information obtained from the mill visits and the BMP survey was used to classify each
bleached kraft and sulfite mill into one of three BMP implementation categories. These
initial mill classifications were supplemented and verified by mill operators through the
American Forest and Paper Association (AF&PA) for virtually all bleached kraft and
papergrade sulfite mills currently subject to the BMP regulation, as well as for dissolving
kraft and dissolving sulfite mills (24).
Based on findings from the mill visits and on information provided by several mill operators,
industry efforts at kraft spent pulping liquor management, spill prevention, and control can
be classified as either mostly proactive or mostly reactive. The proactive spent pulping
liquor management programs are characterized by the following features:
• Management of process operations to minimize variability to the maximum
extent possible;
nRr-0sa
0327-01.nd 7-1

7.0 Spent Pulping Liquor Management, Spill Prevention, and Control:
Current Industry Practice
• A high level of management commitment, and operator awareness and
training (operators are required to address spent pulping liquor losses);
• Extensive preventive maintenance programs for spent pulping liquor
equipment;
• Automated spill detection and spent pulping liquor recovery systems in the
pulping and recovery areas that are maintained and operated by pulping and
recovery personnel;
• Secondary containment and/or high-level alarms on weak and strong spent
pulping liquor tanks;
• Frequent operator surveillance of spent pulping liquor equipment and tanks,
and immediate repairs to this equipment;
• Sufficient capacity (250,000 gallons to > 1,000,000 gallons) for the storage of
spilled materials and planned liquor diversions;
• Systems to recover fiber and spent pulping liquor from knotting and screening
operations; and
• Secondary monitoring and diversion systems for all major mill sewers that
serve pulping, recovery, and recausticizing areas.
In the reactive spent pulping liquor management programs, spill response is emphasized
more heavily than spill prevention. Wastewater treatment plant operators most often use
conductivity monitoring systems to detect problems in the major mill sewers and at the
influent to the treatment plant. Typically, it is their responsibility to notify pulping and
chemical recovery superintendents of any detected problems. In these instances, the pulping
and chemical recovery areas of the mills generally do not have primary responsibility for
spill detection.
For many of the proactive pulping liquor management programs, engineering controls and
monitoring systems observed at kraft and soda mills are consistent with those recommended
NRI-OBa
0327-01.nri 7-2

7.0 Spent Pulping Liquor Management, Spill Prevention, and Control:
Current Industry Practice
by NCASI in 1974 (21). NCASI Technical Bulletin No. 276 contains recommended
approaches for spill containment for all aspects of pulp and paper mill operations, sewer
monitoring, and management programs.
7.1.1 Management Commitment
Bleached kraft mills equipped with oxygen delignification systems and effective spent
pulping liquor management and control systems are characterized by relatively low effluent
discharges of COD (< 25 to 38 kg/ADMT of unbleached pulp produced) and BODS (< 2
kg/ADMT), and by low variability in the effluent discharges. Operators at mills with
effective control systems stress the importance of management commitment, operator
awareness and training, preventive maintenance, and daily management of,spent pulping
liquor inventories. These factors are cited as more important than the presence of
collection and containment systems. The emphasis at these mills is clearly on proactive
approaches to prevent spent pulping liquor losses and spills at the process areas, rather than
on reactive responses to losses and spills that occur.
At mills with effective spent pulping liquor control systems, operators conduct walk-throughs
of critical process areas at least once per shift to identify problems. The operators can
initiate minor repairs, such as tightening pump packings, on the spot. More extensive
repairs are addressed through work order systems, and repairs are completed quickly.
Mill operators of the most effective spent pulping liquor control systems also conduct daily
trend analyses of sewer losses at critical locations to detect low-level leaks and spills at an
early stage. Most operators use conductivity to measure tosses; others use COD analyses
of grab or daily composite samples. At one mill, operators use a one-day BODS test to
detect losses of spent pulping liquor and soap. The results are plotted daily, and statistical
process control is used to assist the operators in identifying trends and target areas for
NRJ-088
0327-01.nrf 7-3

7.0 Spent Pulping Liquor Management, Spill Prevention, and Control:
Current Industry Practice
surveillance and repair. The target sewer-loss levels are reviewed periodically and reduced
over time as part of a continuous improvement program. At this mill, shift operators are
provided with information to determine spent pulping liquor loss control performance, as
well as tools to correct problems as they arise, within established parameters.
Most engineers agree that it is easier to install effective spill control systems during the
design and construction of new mills than to retrofit such systems into old mills. However,
EPA visited two of the oldest bleached kraft mills in the United States, both originally
constructed in the early 1900s. One mill discharges an average of 21 kg COD/ADMT, and
the other mill discharges 28 kg COD/ADMT. Color discharges average 43 kg/ADMT and
28 kg/ADMT, respectively. These data are monthly averages.
Each of these two mills has oxygen deligniflcation on one pulping line, which represents
roughly half of the mill's total pulp production. Each mill also has dry debarking, effective
brownstock washing, closed screen rooms, spill sumps with conductivity alarms in all black
liquor areas (about five sumps at each mill), and conventional secondary biological
treatment systems. Both mills have spent pulping liquor spill storage tanks considerably
smaller than those discussed in Section 9.0 of this report. Neither mill has any staff
dedicated to spill control, but the philosophy of "do not spill" is evident in all production
activities. This philosophy has been developed by formal training and continuous emphasis
on avoiding spills in daily management and supervisory activities. Neither mill has any
accounting of the labor cost of spill control. Although such costs are not trivial, they are
certainly less than the costs for installing extensive tertiary effluent treatment systems to
achieve similar effluent quality from an equivalent mill with poor spill control. Technical
personnel at these two mills believe that operator training and awareness is the most
significant feature of their effective spill control programs.
RJ-088
0327-01.ncj 7-4

7.0 Spent Pulping Liquor Management, Spill Prevention, and Control:
Current Industry Practice
7.1.2 Equipment Requirements
As described above, mill operators confirm that the non-hardware aspects of spent pulping
liquor management and control are, by far, the most important aspects of minimizing liquor
losses and adverse impacts on wastewater treatment systems. Nonetheless, some hardware
is required to effectively control and manage intentional spent pulping liquor diversions and
unintentional losses and spills. Effective systems are designed with the following concepts:
• Identification of discrete spill collection areas in process areas with the
potential for significant liquor and fiber losses (i.e., brownstock washing lines,
evaporators, digesters, recovery boilers, tank farms, etc.) and installation of
strategically located liquor collection sumps in each area;
• Diversion of clean streams from potential spill areas to avoid dilution of
recovered spent pulping liquors;
• Collection of diverted or spilled liquor at the highest possible liquor solids
concentration;
• Return of collected liquor and fiber to the process at appropriate locations;
• Curbing and diking to isolate critical process areas (including soap and
turpentine processing areas) from the wastewater treatment facilities; and
• Conductivity monitoring at strategic locations to detect losses and spills.
Mill operators can divert floor trench drains around brownstock washers by gravity flow to
collection tanks. To further avoid dilution, weak spent pulping liquor can be used for
washdowns in the washer areas. Many operators collect concentrated evaporator boil-out
solutions and liquor diverted from recovery boilers during maintenance for reclamation
before dilution with other waters. Several mills have installed fiber reclaim tanks and fiber
filters to recover fiber from losses in the digester and washer areas. As noted above, the
approach taken by many mill operators is to establish discrete spill and liquor recovery areas
:vtu-oss
0327-01.nq 7-5

TO Spent Pulping Liquor Management, Spill Prevention, and Control:
Current Industry Practice
in critical process areas (e.g., digesters, evaporators, recovery boilers, browmstock washers,
knotters, and screens) and to provide liquor collection sumps for each area. These mulls use
flow-through conductivity-actuated liquor collection sumps to collect liquor at preset
conductivity levels that reflect liquor solids concentrations that can be recovered
economically.
Figure 7-1 provides a plot of black liquor solids versus (vs.) conductivity for a southern
unbleached kraft mull for a range of 0 to 16% black liquor solids (25). These data show a
high correlation between conductivity and the percent of liquor solids. Although these
results may not be directly applicable to all kraft mills, they are presented to demonstrate
the high correlation of conductivity to liquor solids, which supports the use of conductivity
as a surrogate measure for day-to-day mill operations.
There are two approaches regarding the volume of spent pulping liquor storage capacity that
is needed to operate effective spill control systems. One approach holds that the volume
of available capacity should be as large as possible to allow for the collection of large
volumes of spilled or diverted liquor. The other approach holds that the volume of
available spill storage capacity should be as low as possible to foster minimal process
variability, more effective liquor management, and preventive maintenance.
The latter approach was found at the mills that have been operating effective spent pulping
liquor control systems for many years. The large-capacity approach appears to be more
prevalent in mills that are currently investigating and installing spent pulping liquor
containment systems. Thus, mill operators with long and successful experience in spent
pulping liquor spill control favor minimal-capacity liquor spill storage tanks, while many of
those working on theoretical new designs of spent pulping liquor systems favor large-capacity
liquor spill storage tanks. At mills where spill storage capacity is large, there is the potential
for shift operators to pass a problem to the next shift rather than to deal with it
NRJ-M
0327-01.nrj 7-6

7.0 Spent Pulping Liquor Management, Spill Prevention, and Control:
Current Industry Practice
immediately. Based on an evaluation of trills with effective spent pulping liquor control
systems, a moderate amount of liquor spill capacity is necessary, but the amount should be
minimized to foster spill prevention, rather than spill collection and control. A summary
of black liquor storage capacity data for two kraft mills and one soda mill are presented in
Table 7-1. Pulping liquor storage capacity data for three sulfite mills are presented in
Table 7-2.
Process area curbing and diking are also important to isolate process areas from wastewater
treatment systems by diverting spilled or diverted spent pulping liquor to appropriate liquor
collection sumps. Process area curbing and diking for soap and turpentine processing areas
help prevent adverse impacts on wastewater treatment systems from spills and losses of
these materials, which can be high in toxic materials and BOD,. Soap is a material that
is high in organic content (850,000 to 950,000 milligrams per liter (mg/L) of BOD, reported
for one mill (26)) and toxic to aquatic life and micro-organisms in biological treatment
systems. Soap does not contribute significantly to conductivity; thus, soap spills and losses
are not detected by conductivity-based monitoring systems unless pulping liquor is also
present. Turpentine is also highly toxic and also does not contribute significantly to
conductivity. Consequently, it is important to minimize the risk of accidental losses of these
materials from processing areas and storage tanks through proper operation and design and
frequent visual inspections.
7.1.3 Economical Recovery of Spent Kraft Pulping Liquors
The concentration of black liquor solids at which dilute black liquors can be economically
recovered depends on several factors. The benefits of recovering black liquor losses are as
follows:
`Ri-093
0327-Ot.nrl 7-7

7.0 Spent Pulping Liquor Management, Spill Prevention, and Control:
Current Industry Practice
• Energy value;
• Cost of replacement chemicals, primarily equivalent saltcake;
• Reduction in BODS load on the effluent treatment system; and
• Reduction in color and COD discharge in the treated effluent.
The energy value and cost of replacement chemicals can readily be calculated on a mill-
specific basis, while the values associated with effluent reductions are more difficult to
ascertain. A brief discussion of liquor solids levels that may be economical to recover at a
typical bleached kraft mill (27) is presented below.
The value of recovered chemicals is significant in cases where mills purchase saltcake.
However, for today's bleached kraft mills, where high chlorine dioxide substitution and
effective brownstock washing are becoming the norm, there is usually an excess of saltcake.
It is likely that less than half of the bleached kraft mills in the United States can assign a
credit for recovered saltcake, and that very few mills will be able to do so in the future as
brownstock washing and bleaching operations are upgraded.
Assuming a typical evaporator steam economy of 4.5 (kg of water evaporated per kg of
steam) and a recovery boiler efficiency of 60%, the combustion of 1 kg of black liquor solids
produces sufficient steam to evaporate about 18 kg of water. The recovery of 1 kg of black
liquor solids will also reduce the BOD, load on the effluent treatment system by about 0.15
kg, which in turn will reduce operating costs by approximately 5 cents. This amount is
equivalent to the cost of steam to evaporate about 6 kg of water.
Therefore, in most bleached kraft mills where excess saltcake is produced, the financial
value of recovering 1 kg of black liquor solids is equivalent to evaporating about 24 kg water
(18 kg + 6 kg). In this case, the break-even liquor solids concentration, the point at which
evaporation costs are equal to the value of the recovered liquor, is approximately 4%. At
mills where recovered liquor will offset the need to purchase saltcake, the economical liquor
solids concentration for recovery can be as low as 1%.
vxt-0as
0327-01.nq 7-8

7.0 Spent Pulping Liquor Management, Spill Prevention, and Control:
Current Industry Practice
Where a mill lacks sufficient evaporator capacity, the break-even cost will be higher because
an allowance for increasing the evaporator capacity will be required. Conversely, there
could be substantial investment and operating cost savings in cases where spent pulping
liquor spill recovery systems reduce or eliminate the need for treatment of the effluent color
or the expansion of a biological treatment system. Any cost credits for reducing effluent
color or COD will depend on the alternative costs of compliance with each mill's discharge
requirements for these pollutants, if any.
Some mills collect dilute spent pulping liquors down to 1% liquor solids and less. These
mills are driven by the need to control effluent color. Other mills collect liquor solids to
the point where the value of the recovered fiber, chemicals, and energy exceeds the cost of
evaporating dilute liquors. These mills collect spent pulping liquor at liquor solids
concentrations of 2 to 5%. As described above, this determination is highly mill-specific and
depends on available evaporator capacity and saltcake balance.
Although not required by the BMP regulation, spill prevention and control for white and
green liquors at kraft mills will likely be cost-effective in many cases.
7.2 Sulfite Mills
At the sulfite mills, spent pulping liquor management, spill prevention, and control programs
include many of the same features described above for kraft and soda mills; however, none
of the surveyed sulfite mills have automated spent pulping liquor spill detection and
recovery systems in the pulping and chemical recovery areas. One mill has a fiber and
liquor recovery system at the brownstock washers. Most of the mills do not have full
secondary containment for weak and strong spent pulping liquor tanks. High-level alarms
on liquor tanks appear to be standard practice. All mills are equipped with pH and/or
conductivity meters and alarms at strategic locations to identify spills or upsets. Some mills
vtu-0as
0327-01.nd 7-9

7.0 Spent Pulping Liquor Management, Spill Prevention, and Control:
Current Industry Practice
have diversion tanks or ponds for large spent pulping liquor diversions or spills. Protection
of the wastewater treatment facilities is the main objective for these systems. One sulfite
mill reported an extensive proactive spent pulping liquor spill prevention and control
program that included all of the elements described above for the kraft mills (28). The
following techniques can be used to substantially minimize spent pulping liquor losses from
most sulfite mills (2,28):
• Spill collection systems for the digester, pulp washing, and screening areas
with recovery of fiber and spent pulping liquor losses;
• High-level alarms on spent pulping liquor and stock tanks;
• Flow recorders and continuous monitors and samplers on major process area
sewers;
• Collection of tank overflows from heavy to weak liquor tanks;
• Extra equipment capacity to handle spills and upset conditions; and
• An ability to return heavy liquor and compatible boil-out solutions to weak
liquor tanks instead of the sewer.
Ntu-0ss
0327-01.nn 7-10

7.0 Spent Pulping Liquor Management, Spill Prevention, and Control:
Current Industry Practice
Table 7-1
Black Liquor Storage Capacity - Kraft and Soda Mills
Tank Volume (Gallons) and Typical Operating Level (%)
Tank Mill A Mill B Mill C
Weak Liquor 852,000 (25 - 84%) 1,500,000 (75%) 686,000 (25 - 75%)
852,000 (25 - 84%)
Strong Liquor 177,000 (50%) 152,000 (90%) 158,000 (60 - 70%)
Strong Waste or 837,000 ( 0%) 345,000 ( 0%) 1,500,000 (30 - 35%)
Spill Tank
Fiber Salvage 57,000 (20 - 35%)
Intermediate 345,000 ( 0%)
Liquor
Wastewater 5,000,000
Diversion Basin
Source: EPA Project Files: Pulp, Paper and Paperboard Effluent Limitations Guidelines
iv-0as
0327-01.nn 7-11

7.0 Spent Pulping Liquor Management, Spill Prevention, and Control:
Current Industry Practice
Table 7-2
Pulping Liquor Storage Capacity - Sulfite Mills
Tank Volume (Gallons) and Typical Operating Level (%)
Tank Mill E Mill F Mill G
Accumulators 65,000 (80%) 50,000 (50%)
95,500 (70%)
Fresh Acid Storage 85,000 (50%) 300,000 (65%)
Weak Liquor Storage 88,000 (60%) 1,650,000 (50%)
Strong Liquor Storage 1,650,000 (50%)
Diversion Tank 1,200,000 (40%) Not specified 5,000,000
or Basin
Source: EPA Project Files: Pulp, Paper and Paperboard Effluent Limitations Guidelines
NP.t-0sa
0327-01.nd 7-12

7.0 Spent Pulping Liquor Management, Spill Prevention, and Control:
Current Industry Practice
Figure 7-1
Black Liquor Solids vs. Conductivity
80
y 60
0
t
� Co
—
o
40
a o
a
C
U 20
0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Black Liquor % Solids
R Squared = 0.976
Source: PCA, 1995 (25)
NIU-0M
0327 01nrl 7-1 3

8.0 'BMP REGULATORY APPROACH, REQUIREMENTS, AND
IMPLEMErTATION
8.1 Regulatory Approach and Regulatory Requirements
EPA's regulatory approach for controlling losses of spent pulping liquor is to require, by
regulation, that the owner or operator of each chemical pulp mill subject to the regulation
develop and implement Best Management Practice Plans (BMP Plans) to prevent and
control spent pulping liquor losses, other than those losses associated with normal
brownstock pulp washing. For direct dischargers, this requirement will be implemented
through their NPDES permits. For indirect dischargers, this requirement will be
immediately applicable, subject to the compliance dates established in the regulation.
In many respects, the BMP Plans will be similar to the Spill Prevention Countermeasure and
Control (SPCC) Plans that are prepared for oil spill prevention and control (see 40 CFR
112.7). The primary objective of the BMP Plans is to prevent losses and spills of spent
pulping liquors, soap, and turpentine; a secondary objective is to collect, contain, recover,
or otherwise control spills and losses that do occur. Pulp mill operators should ensure that
no leaks or spills of spent pulping liquors are visible in their mills.
Under EPA's regulatory approach, mill owners or operators will be required to prepare a
proactive BMP Plan for spent pulping liquor, soap, and turpentine within general objectives
and guidelines. The detailed provisions of each BMP Plan will be developed by mill
operators and will be tailored to the specific circumstances at each mill. The BMP Plan
should address the following general areas:
• Management Commitment and Approval;
• Employee Awareness and Training;
• Preventive Maintenance;
• Work Practices;
• Surveillance and Repair Programs;
• Engineering Analyses;
NRJ-M
asn-oi.nd 8_1

8.0 BMP Regulatory Approach, Requirements, and Implementation
• Engineering Controls and Containment;
• Dedicated Monitoring and Alarm Systems; and
• Monitoring of BMP Implementation.
L ,
The BMP Plans prepared by the mills must contain the following twelve key elements:
1. An indication of approval and commitment of resources by mill management.
2. A program of initial and refresher training of operators, maintenance
personnel, and other technical and supervisory personnel who have
responsibility for operating, maintaining, or supervising the operation and
maintenance of spent pulping liquor equipment and systems. The refresher
training must be conducted annually. The training must be documented, and
records of training must be maintained for inspection by federal and state
regulatory personnel.
3. Development and implementation of preventive maintenance practices,
standard operating procedures, work practices, engineering controls, and
monitoring systems to prevent spent pulping liquor losses and to divert spent
pulping liquor to containment facilities such that the diverted or spilled liquor
may be returned to the process or metered to the wastewater treatment
system.
4. A program of regular visual inspections (at least once per operating shift or
once per day) of spent pulping liquor equipment and a program for repair of
leaking equipment. The repair program must encompass immediate repairs
when possible, and quick repair during the next maintenance outage, for
leaking equipment that cannot be repaired during normal operations. The
mill must also establish conditions under which production will be curtailed
or halted to repair leaking equipment or to prevent spent pulping liquor
losses. Under the repair program, repairs should be tracked over time to
identify equipment that may need to be upgraded or replaced, based on the
frequency and severity of leaks or failures.
5. A detailed engineering review of the pulping and chemical recovery
operations, including but not limited to, process equipment, storage tanks,
pipelines and pumping systems, loading and unloading facilities, and other
appurtenant spent pulping liquor pulping and recovery equipment, to
NR3-osa
0327-01.nq 8_2

8.0 BMP Regulatory Approach, Requirements, and Implementation
determine the magnitude and routing of potential leaks, spills, and intentional
spent pulping liquor diversions during the following periods of operation:
• Startups and shutdowns;
• Maintenance;
• Grade changes;
• Storm events;
• Power failures; and
• Normal operations.
6. A detailed engineering review of existing spent pulping liquor containment
facilities to determine whether there is adequate capacity for the collection
and storage of anticipated intentional spent pulping liquor diversions with
sufficient contingency space for the collection and containment of spills, based
on good engineering practice. Secondary containment equivalent to the
volume of the largest spent pulping liquor storage tank, plus sufficient
freeboard for precipitation, should be provided for bulk storage tanks.
Alternatively, mill operators may substitute a periodic tank integrity testing
program for hard secondary containment for spent pulping liquor storage
tanks. Hard secondary containment must be provided for turpentine storage
tanks.
The engineering review must also consider the potential for contamination of
stormwater from the immediate process areas (from digesters, evaporators,
recovery boilers,etc.). Segregation and collection of contaminated stormwater
from the process areas must be considered.
7. An implementation schedule not to exceed 36 months for the construction of
any spent pulping liquor containment or diversion facilities necessary to fully
implement the BMP Plan. An implementation schedule not to exceed 24
months should also be prepared for the installation or upgrade of continuous,
automatic monitoring systems,including but not limited to,high-level monitors
and alarms on existing storage tanks, process area conductivity (or pH)
monitoring and alarms, and process wastewater and wastewater treatment
plant conductivity (or pH) monitoring and alarms. The exact compliance
dates will be determined by the promulgation date of the regulation for
indirect dischargers, and by a combination of the promulgation date and the
NPDES permit issuance date for direct dischargers.
NRJ-088
0327-0t.nd 8-3

8.0 BMP Regulatory Approach, Requirements, and Implementation
8. A program of "boards of review" to evaluate each spill not contained in the
immediate process area and any unusual, intentional spent pulping liquor
diversions. The boards of review should be conducted as soon as possible,
generally within two or three business days after the event, and should be
attended, as practical, by the involved operators (or their supervisors),
maintenance personnel, process engineering personnel, and representatives of
mill management and environmental control staff. A brief report must be
prepared for each board of review. The report must describe the
circumstances leading to the incident, the corrective actions taken, and the
recommended changes to operating and maintenance practices to prevent
recur: :ce. A summary of the boards of review reports should be made part
of the annual refresher training. The reports prepared for the boards of
review must be maintained for inspection by federal or state regulatory
personnel.
9. A program to review beforehand any modifications to the pulping and
chemical recovery facilities and any construction activities in the pulping and
chemical recovery areas. The purpose of these reviews is to ensure that spent
pulping liquor spill prevention and control is considered as part of the
planned modifications, and that construction and supervisory personnel are
aware of possible liquor diversions and the potential for causing liquor spills
or losses during construction.
10. A continuous BMP implementation monitoring program to track the
performance and effectiveness of BMPs in terms of untreated wastewater
loadings of COD, TOC, or other measure of organic loading. This program
must include daily wastewater treatment system influent (or mill sewer system
influent) and effluent monitoring for COD, TOC, or other short-term
measures of organic loading; establishment and revision, as appropriate, of
mill-specific control limits for untreated wastewater mass loadings; and a
quarterly reporting program for the NPDES permit or pretreatment authority.
11. A review and certification of the BMP Plan by the mill technical manager,
pulping area production manager, or other person of similar responsibility
designated by the mill manager. A certification by a Registered Professional
Engineer familiar with the facility and the requirements of the BMP
regulation, although desirable, is not required by this regulation. The
technical manager or other person certifying the BMP must attest that it has
been prepared in accordance with the requirements of the regulation and in
accordance with good engineering practices.
`Rr-088
0327-01.nt 8-4

8.0 BMP Regulatory Approach, Requirements, and Implementation
12. A review and update of the BMP Plan as necessary, at least every three years,
or whenever there are significant changes to the mill's pulping and chemical
recovery facilities.
Owners or operators of mills that directly discharge wastewater will be required to prepare
and implement their BMP Plans by the date on which the NPDES permit conditions
imposing the BMP requirements are issued, or by the relevant deadline listed below,
whichever is later. If a deadline specified in the regulation has passed at the time the
permit is issued, the permit will require immediate compliance with all BMP requirements
subject to such deadlines at the time it is issued. Owners or operators of mills that
indirectly discharge wastewater will be required to prepare and implement their BMP Plans
in accordance with the schedule listed below. Owners or operators of new mills will be
required to develop their BMP Plans before discharging any wastewater and to implement
their BMP Plans after the first discharge of wastewater from the mill.
The milestones and compliance dates for the BMP regulation are as follows:
Milestone Compliance Date
1. Complete BMP Plan and implement engineering 6 months after
analyses, preventive maintenance, work practices, promulgation date
surveillance and repair programs, and employee
training.
2. Establish initial organic loading control limits. 6 months after
promulgation date
3. Complete construction of dedicated monitoring and 24 months after
alarm systems. promulgation date
4. Complete construction of engineering controls and 36 months after
containment, and associated monitoring and alarm promulgation date
systems.
5. Establish revised organic loading control limits. 45 months after
promulgation date
Nrv-M
0327-01.nq S_5

8.0 BMP Regulatory Approach, Requirements, and Implementation
The complete text of the BMP regulation is provided in Attachment A.
8.2 Implementation Guidance for Permit Writers and Pretreatment Authorities
As described above, mill owners or operators will be required to develop and implement
spent pulping liquor BMP Plans that are tailored to the specific circumstances at each mill.
To assist in the implementation of the regulation through the NPDES permit and
pretreatment programs, implementation guidance for permit writers, pretreatment
authorities, and the industry is provided in Sections 8.2.1 through 8.2.5.
8.2.1 Applicability of BMP Regulation to Pulping Liquors Other Than Spent
Pulping Liquor
Although the BMP regulation is specific to spent pulping liquors, EPA anticipates that
similar BMPs and controls will be implemented for white liquor, green liquor, and fresh
sulfite pulping liquor at many mills; however, mill owners or operators are obligated to
address only spent pulping liquor as part of the BMP regulation. The regulation does not
mandate that any particular types of controls be installed, nor that spent pulping liquor be
recovered at any particular liquor solids concentration. Permit writers and pretreatment
authorities have additional authority under Section 402 of the CWA and the NPDES permit
and pretreatment regulations in Sections 403.8 and 122.44(k) of the CWA, respectively, to
extend BMP requirements to other pulping liquors and other substances at pulp and paper
mills, where they deem appropriate.
8.2.2 Requirements for Specific BMP Equipment Items
Secondary containment for turpentine storage tanks, and curbing or diking for soap and
turpentine processing areas, are required by the BMP regulation. Otherwise, the BMP
NRu-0as
0327-01.nq 8-6

8.0 BMP Regulatory Approach, Requirements, and Implementation
regulation does not mandate that specific equipment items, monitoring systems, or alarm
systems be used to comply with the regulation. EPA intends that mill owners or operators
should have maximum flexibility to address management and control of spent pulping liquor
at their mills, within the context of general regulatory requirements. The specific types of
equipment described in Section 9.0 were selected by EPA for the purpose of developing
estimated industry-wide costs to comply with the regulation. Although these equipment
items and associated control strategies are among those judged to be appropriate and
effective, mill owners or operators are not constrained by the regulation to use any
particular equipment item or control strategy.
8.2.3 Costs of BMP Compliance
As part of its effort to characterize the economic impact of the effluent limitations
guidelines and standards on the pulp and paper mills, EPA estimated industry-wide costs
to comply with the BMP regulation (see Section 9.0). EPA believes the cost estimates
presented in Section 9.0 are reasonable based on comparisons made with actual costs
incurred by mill operators who have implemented effective BMP programs, and on a review
of independent cost estimates provided by several mill operators. The BMP regulation does
not require that mill owners or operators incur a specific cost to comply with the regulation.
8.2.4 Recovery of Liquor Solids Under BMP Regulation
As described in Section 7.0, the level of liquor solids that may be economical to recover is
mill-specific and depends on factors such as saltcake balance, available evaporator capacity,
and the need to control effluent color and other pollutants. The BMP regulation does not
mandate that mill owners or operators recover dilute liquors at a particular liquor solids
concentration (e.g., 1% black liquor solids). The intent of the regulation is that mill owners
or operators will determine an appropriate target level of liquor solids recovery as part of
Nw-0sa
0327-01.nrl 8-7

8.0 BMP Regulatory Approach, Requirements, and Implementation
the engineering review that is required by the regulation. As mills are modernized and
upgraded, EPA anticipates that new pulping and chemical recovery facilities, including
additional evaporator capacity,will be designed and installed to achieve more effective spent
pulping liquor control.
8.2.5 Monitoring of BMP Implementation
EPA is requiring monitoring of the BMP implementation at pulp and paper mills for two
reasons: (1) to provide a framework for monitoring the performance and effectiveness of
BMPs on a continuing basis; and (2) to establish an early warning system to detect trends
in spent pulping liquor losses that might not otherwise be obvious. The BMP monitoring
program involves establishing upper operating control limits on a measure of organic loading
at the influent to the wastewater treatment system or at another key location or locations
in the mill sewer system, and responding to exceedances of these control limits with
investigative and corrective actions, as appropriate. The BMP regulation requires mill
owners or operators to establish initial control limits based on at least six months of
monitoring data, and to revise these limits after the BMP Plan has been fully implemented.
Exceedances of the upper control limits will not constitute violations of NPDES permits or
pretreatment permits; however, failure to conduct the required BMP monitoring, or failure
to conduct investigative or corrective actions when such limits are exceeded, would
constitute permit violations.
EPA believes that COD is among the best, if not the best, pulp mill wastewater
characteristic that can be monitored to fulfill this provision of the BMP regulation. The test
method for COD is highly reproducible and can be performed in a short period of time,
unlike the BOD5 test method. It also has the advantage of being responsive to losses of
turpentine and soap, unlike conductivity, which is not responsive to these materials.
Alternative pulp mill wastewater monitoring characteristics could include Total Organic
NRJ-0sa
0327-01.nq 8-8

8.0 BMP Regulatory Approach, Requirements, and Implementation
Carbon (TOC), a simplified one-day BOD, test, or another similar short-term measure of
organic loading. The objective is to use an analytical method that can be performed within
one day of sampling, which will allow for timely data assessment.
The BMP regulation requires daily monitoring of the wastewater treatment system influent
(or an alternative sewer system location), as well as the wastewater treatment system
effluent. At each location, mass loadings of COD, TOC, or another short-term measure of
organic loading will serve as a primary indicator of how well the mills are implementing
their BMP Plans. Daily effluent monitoring for the same constituent is also required to
assess possible impacts on the wastewater treatment system on a continuing basis.
Mill owners or operators are required to establish statistically-derived, running seven-day
average 75th- and 90th-percentile upper control limits that reflect normal mill operation,
with no abnormal spills or losses of spent pulping liquor, soap, or turpentine. When the
75th-percentile upper control limit is exceeded, mill operators are required to initiate
appropriate investigative actions to determine potential abnormal liquor losses and to
initiate corrective actions, as appropriate. If the 90th-percentile upper control limit is
exceeded, mill operators are required to initiate corrective actions to bring the monitored
mass loadings of COD, TOC, or another organic measure to a level below the established
control limit.
Figures 8-1 and 8-2 present actual 1988 and 1992 COD data for a mill that installed spent
pulping liquor spill controls during 1990 and 1991. Figure 8-1 shows the wastewater
treatment influent COD levels without BMPs; Figure 8-2 shows the wastewater treatment
influent COD levels with BMPs. As shown on the figures, if appropriate corrective actions
had been implemented, several exceedances of the control limits may have been avoided.
The exceedance of the upper control limits shown on Figure 8-2 during mid-1992 coincided
with a violation of a NPDES permit effluent limitation (see Figure 9-6).
tiRJ-M
0327-01.nry 8-9

8.0 BNIP Regulatory Approach, Requirements, and Implementation
The BMP regulation requires that mill owners or operators provide quarterly reports to
NPDES and pretreatment authorities that show the established upper control limits, daily
influent and effluent monitoring data, seven-day running average dam- and brief narrative
descriptions of any corrective actions taken to bring influent mass loadings within the
established upper control limits. As noted above, exceedances of the influent upper control
limits will not constitute violations of NPDES permits or pretreatment permits; however,
failure to conduct influent and effluent monitoring, or failure to conduct remedial measures
to bring the influent mass loadings below the established upper control limits within a
reasonable amount of time, would constitute permit violations.
Mill owners or operators must establish upper control limits for influent or sewer system
mass loadings within 6 months after the preparation of the initial BMP Plan. The control
limits must be revised no later than 9 months after implementation of the final BMP Plan
(see regulatory provisions provided in Attachment A).
NRJ-088
0327-01.nq 8-10

8.0 BMP Regulatory Approach, Requirements, and Implementation
Figure 8-1
Wastewater Treatment Influent COD Levels Without BMPs
ro 500
b
6
+00 75th Percentile 90th Percentile
U
CD
m
a
r=
IC
(D 300
Cb C ---------- ---- ---- -
- - - - - ------ -
m
Q
C 200
ado
� 100
1988
Source: EPA, 1993 (19)
NR34M
0327-0l.nd

8.0 BMP Regulatory Approach, Requirements, and Implementation
Figure 8-2
500 Wastewater Treatment Influent COD Levels With BMPs
U
C*
O
T
\- 400
Q
O
U
75th Percentile Mh Percentile
ZZ
c
m 300
rn
w
m
- --------- - -------- ----- - - - -
a
c 200
cc
N
Q
c
100 -- -
Source: EPA, 1993 (19) 1992
NRl-088
0327-0Lnq 8-12

9.0 ESTIMATED COSTS AND EFFLUENT REDUCTION BENEFITS
This section presents a discussion of the methods that were used to estimate industry-wide
costs to fully implement BMP Plans for spent pulping liquor at pulp and paper mills.
9.1 Current Status of Spent Pulping Liquor Spill Prevention and Control
Svstems in United States
A wide variety of spent pulping liquor spill prevention and control practices exist in the pulp
and paper mills in the United States. Many older and complex mills have been operating
proactive, highly effective spent pulping liquor spill prevention and control systems for many
years. Many other mills have fairly limited spill prevention and control systems. EPA
evaluated the current status of the industry using information obtained during mill visits, the
results of the NCASI BMP survey, and follow-up contact with the AF&PA (24). The mills
were divided into three categories, based on the status of their spent pulping liquor spill
prevention and control systems, as follows:
Category 1: Mills with most of the major components of a spent pulping liquor
control system in place. Incremental investment costs at these mills
are not expected to exceed 10% of the estimated total investment costs
(excluding costs for preparation of initial BMP Plan) (see Section 9.2).
Category 2: Mills with some of the major equipment items of a spent pulping
liquor control system in place (e.g., a few liquor collection sumps,
liquor storage tanks, sewer conductivity monitoring, etc.). At these
mills, as much as 60% of the estimated total investment costs may be
necessary to fully implement a BMP Plan.
Category 3: Mills with relatively little spent pulping liquor control equipment in
place. At these mills, as much as 90% of the estimated total
investment costs may be required to implement a BMP Plan.
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0327-01.nd 9-1

9.0 Estimated Costs and Effluent Reduction Benefits
Table 9-1 presents the status of spent pulping liquor BMP implementation at pulp and paper
mills. A summary of this status is presented below:
Percent of Mills Percent of Mills in Percent of Mills in
Type of Mill in Category I Category 2 Category 3
Kraft and Soda Mills 26% 29% 45%
Sulfite Mills 20% 33% 47%
9.2 Equipment Costs for BMP Implementation at Pulp and Paper 'Mills
To develop the industry-wide costs, kraft and sulfite mills were first classified by the level
of complexity of their pulping and chemical recovery systems. Single line mills were defined
as mills with one fiberline (e.g., one continuous digester or one set of batch digesters, one
or two pulp washing lines, etc.). Moderately complex mills were defined as mills with two
fiberlines. Complex mills were defined as mills with more than two fiberlines, multiple sets
of evaporators, and multiple recovery boilers. Complex mills are usually older mills that
have been modernized and expanded. These classifications are independent of pulp
production capacity because the complexity of a mill is most often the primary factor that
drives investment costs for the installation of spent pulping liquor spill prevention and
control systems.
For each level of mill complexity, the types of equipment necessary to operate effective spill
control systems were determined. This equipment included liquor collection sumps, liquor
storage capacity, fiber reclaim tanks, process area curbing and diking, turpentine and soap
containment for kraft mills that process softwood, conductivity monitoring and high-level
tank alarms, and costs for engineering analyses, initial BMP Plan preparation, and operator
training. Based on information obtained from mill visits and the results of the NCASI BMP
vx.t-pas
0327-01.nrt 9-2 .

9.0 Estimated Costs and Effluent Reduction Benefits
survey, EPA determined that single line kraft mills will require up to five liquor collection
sumps (relatively small 4'x4'x4' or 4'x4'x8' concrete sumps equipped with conductivity-
actuated liquor recovery pumps). Moderately complex mills will require up to 9 sumps, and
complex mills will require up to 12 sumps. Each type of mill was assigned one 500,000-
gallon spent pulping liquor storage tank for the collection of recovered liquor. One fiber
reclaim tank was assigned for single line mills, and two fiber reclaim tanks were assigned
for the moderately complex and complex mills. The amount of process area curbing and
diking, conductivity monitoring, turpentine and soap containment, and engineering analyses
for initial BMP Plan preparation required for each type of mill was a function of the mill
complexity. A similar process was followed for sulfite mills; however, there are no sulfite
mills with more than one line.
Table 9-2 presents a summary of estimated BMP investment costs for kraft mills to fully
implement effective spent pulping liquor spill prevention and control systems. Table 9-3
presents similar information for sulfite mills. These cost estimates were prepared assuming
the mills had no spill control equipment in place. The total investment costs for each type
of mill are summarized below:
Kraft Mill
Type of Mill Investment Costs Sulfite Mill Investment Costs
Single Line Mills $ 2,150,000 $ 1,300,000
Moderately Complex Mills $ 3,250,000 None
Complex Mills $ 4,050,000 None
Based on information obtained from mill visits, NCASI BMP questionnaire responses, and
reports in the literature, EPA determined that the following items contribute to the annual
costs for implementing spent pulping liquor BMPs:
N RJ-0sa
0327-m.nd 9-3

9.0 Estimated Costs and Effluent Reduction Benefits
• Evaporation of recovered liquor;
• Operation and maintenance of new equipment;
• Tank integrity testing program; and
• Operator training.
The BMP implementation items that contributed to annual cost savings at the mills were
as follows:
• Recovered fiber;
• Recovered pulping chemicals;
• Recovered energy; and
• Reduced wastewater treatment costs for power, nutrient addition, and
sludge disposal.
Most mill operators did not complete the cost sections of the NCASI BMP questionnaires;
the operators who did complete this section generally show a net annual cost savings from
implementation of spent pulping liquor BMPs of$0.20 to $1.00 per ton of brownstock pulp.
A few mills reported net annual costs ranging from $0.01 to $0.35 per ton of brownstock
pulp. A few available reports and other sources of cost data for spent pulping liquor BMP
implementation show annual net cost savings in the range of $500,000 to $750,000, and
payback periods of less than 4 to 8 (19,29).
9.3 Costs and Effluent Reductions - Mill Case Studies
Case studies of cost and effluent reductions resulting from spent pulping liquor
BMP implementation at two kraft mills are presented below.
.Nw-osa
0327-01.nil 9-4

9.0 Estimated Costs and Effluent Reduction Benefits
9.3.1 Southern U.S. Bleached Kraft Mill
Table 9-4 and Figures 9-1 through 9-5 show the impacts of pulping liquor BMPs
implemented at a southern kraft mill that pulps southern pine and discharges process
wastewaters to an adjacent POTW (19). The process wastewater discharge from the mill
accounts for more than 95% of the POTW influent flow. The mill has no on-site wastewater
treatment facilities, and prior to 1991, had virtually no pulping liquor spill prevention and
control facilities. Primary and secondary wastewater treatment have been provided by the
POTW. From 1990 to 1991, the mill installed an extensive pulping liquor spill prevention
and control system for black liquor, green liquor, white liquor, and lime mud. The system
includes several process area liquor collection sumps and refurbished oil storage tanks that
are used to collect pulping liquor. The mill also partially closed a screen room. Relatively
minor operational changes were also instituted at the POTW during that period; however,
the POTW was not upgraded in terms of additional unit operations or additional treatment
capacity.
The first full year of operation of the black liquor spill prevention and control system at the
mill was 1992. Production of brownstock pulp during 1992 was about 6% less than that for
1988. The annual average POTW effluent flow for 1992 was <3% lower than the 1988
annual average, but about 3% higher when normalized to pulp production. Although there
was little change in the total mill wastewater volume resulting from the BMPs (on an
average basis), maximum flows to the POTW were reduced, and there was a marked
decrease in the variation in the effluent flow. Table 9-4 presents a tabular summary of the
changes in the mill's effluent as a result of the black pulping liquor BMP implementation.
Figure 9-1 depicts the reduced wastewater flow to the POTW that occurred after the BMP
implementation.
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0327-01.nq 9-5

9.0 Estimated Costs and Effluent Reduction Benefits
The distribution of POTW influent COD data presented on Figure 9-2 shows a marked
reduction in POTW COD influent loadings. In particular, the 80th percentile to the
maximum value COD loadings were lower after spent pulping liquor controls were
implemented. The overall reduction in the average BOD5 influent loadings was about 20%.
POTW effluent data for COD, TSS, and BOD5, normalized to annual pulp mill production,
showed significant reductions in 95th percentile effluent mass loadings (see Figures 9-3
through 9-5 and Table 9-4).
The reductions in the annual average effluent mass loadings for COD, TSS, and BOD5 were
27%, 57%, and 17%, respectively. The most significant reductions were at the higher
percentile mass loadings, suggesting that effective spent pulping liquor controls reduced
short-term adverse impacts on POTW operations. The reductions in effluent loading were
not always associated with reductions in maximum flows. Although the average POTW
influent COD loading was reduced by 22%, the average POTW effluent loading was reduced
by 27%. These results suggest that the spent pulping liquor controls resulted in removal of
a greater portion of COD material from pulping liquor that is refractory to conventional
biological treatment.
The mill had a spill of turpentine during May 1992, which impacted POTW performance
for late May and part of June 1992. Although not discernable on Figures 9-3 through 9-5,
the adverse impact of the spill resulted in the higher percentile mass loadings of COD, TSS,
and BOD5 shown on these figures. The impact of the spill is more clearly shown on Figure
9-6, which provides a time-series plot of seven-day average POTW effluent BOD5 for 1992.
These results clearly demonstrate the importance of providing proper containment for
turpentine process areas and bulk storage tanks as part of a pulp mill BMP Plan. Had
effective controls been in effect at the time of the spill, it could have been contained, and
the adverse impacts on POTW operations (interference and pass-through) could have been
avoided.
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0327-01 nq 9-6

9.0 Estimated Costs and Effluent Reduction Benefits
Whole effluent toxicity data reported by the POTW show that intermittent acute toxicity to
Daphnia and Pimephales pmmelas was eliminated, as was intermittent chronic toxicity to
Pimephales promelas. Consistent chronic toxicity to Daphnia was substantially reduced,
except during the period of the turpentine spill.
The mill's total investment costs for the spill prevention and control systems, including
refurbishment of two fuel oil storage tanks, was about $4 million dollars (1990-1991). The
mill estimates that the net annual cost savings for recovery of black liquor at 3 to 4% liquor
solids is about $500,000, excluding the cost savings for recovered fiber,which have not been
measured or estimated. The costs incurred at this mill are in line with those presented in
Table 9-2 for BMPs for control of spent pulping liquor, if they are adjusted upward about
$500,000 to $750,000 to account for additional controls for white liquor, green liquor, and
lime mud.
9.3.2 Canadian Bleached Kraft Mill
Another BMP implementation case study involves a Canadian bleached kraft mill with two
fiberlines. The No. 1 pulp mill began operations during 1948 and is now dedicated to
hardwoods, principally aspen. The No. 2 pulp mill began operations during 1978 and
processes mainly black spruce (29,30). The spent pulping liquor spill prevention and control
system was installed in response to a control order issued by the Ontario Ministry of
Environment before the installation of secondary treatment in 1987. Spent pulping liquor
spill prevention and control was identified as the highest-priority project for reducing final
effluent toxicity at the mill (29,30).
NPJ-068
0327-01.nq 9-7

9.0 Estimated Costs and Effluent Reduction Benefits
The major elements of the upgraded spill prevention and control system were:
• Reactivation of the original pulp mill spill tank;
• Installation of a new 120,000-gallon spill tank;
• Installation of a conductivity-activated sump in the No. 2 pulp mill, and
routing of gland water and decker white water around the sump;
• Prevention of softwood fibers from entering the No. 1 pulp mill's hardwood
line;
• Collection of spilled spent pulping liquor in as concentrated a form as
possible;
• Upgrading of the sewer monitoring network; and
• Development of a computer monitoring system for 15 wastewater streams and
37 tanks and vessels.
The capital cost for the upgraded spill prevention and control system was reported at
$2,400,000(1985 Canadian dollars) (29,30). The net annual operating savings were reported
as follows (1985 Canadian dollars):
Savings in Recovered Chemicals $ 700,000
Savings in Recovered Fiber 250,000
Cost of Extra Evaporation of Recovered Liquor (200,000)
Net Annual Savings $ 750,000
From these data, EPA estimated a return on investment of 31% and a payback period of
3.2 years. Mill operators reported that the break-even point for the recovery of dilute black
liquor is about 4% liquor solids, and that recovery of very dilute liquors (< 2% liquor
NRJ-088
0327-01.nij 9-8

9.0 Estimated Costs and Effluent Reduction Benefits
solids) is avoided by collecting spilled or lost liquor before its dilution with other
wastewaters (29,30).
The effluent reduction benefits experienced by the Canadian bleached kraft mill are
described in Table 9-5. The operators at this mill attributed these effluent reduction
benefits to the upgraded spent pulping liquor controls. The effluent reduction benefits were
attained before the installation of an aerated stabilization basin that was completed during
1989 (29,30).
9.4 General Conclusions
Based on the results of these case studies and on other information presented in this report,
EPA believes that improved management of spent pulping liquor and effective spill
prevention and control can result in the following effluent reduction benefits:-
• Reduced mass loadings of priority, non-conventional, and conventional
pollutants in untreated wastewaters, and reduced toxicity of raw waste
loadings prior to biological treatment;
• Reduced toxicity in biologically treated pulp mill effluents;
• Reduced wastewater flows and discharges of priority, non-conventional, and
conventional pollutants;
• Reduced potential for catastrophic spills of spent pulping liquor directly into
waterways; and
• Reduced potential for upsets to wastewater treatment facilities from in-mill
spills, and reduced potential for increased discharges of unchlorinated and
chlorinated toxic compounds, effluent toxicity, and conventional and non-
conventional pollutants (BOD5, COD, and TSS) associated with treatment
system upsets.
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0327-01.nq 9-9

9.0 Estimated Costs and Effluent Reduction Benefits
Non-water quality environmental impacts from improved spent pulping liquor control
systems include:
• Reduced incidental emissions of volatile HAPs, including methanol and
methyl ethyl ketone;
• For kraft mills, reduced incidental atmospheric emissions of odor-causing
TRS compounds, including hydrogen sulfide, methyl mercaptan, dimethyl
sulfide, and dimethyl disulfide;
• Improved energy efficiency resulting from the combustion of black liquor
solids that would otherwise be lost to the sewer (a net increase in energy use
will occur if very dilute weak liquors are processed);
• Improved process efficiency, including a reduced need for make-up chemicals
and more efficient utilization of operating and supervisory personnel; and
• Reduced environmental impacts associated with the manufacture and
transportation of make-up chemicals no longer required at the pulp mill
because of increased spent pulping liquor recovery.
For a typical kraft mill with no BMPs in place, EPA estimates that the average incremental
untreated wastewater BODS loading reduction attainable from effective black liquor spill
prevention and control is about 5 kg/ADMT of brownstock pulp (2). Accordingly, for mills
with adequate black liquor spill prevention and control programs, there will be no
incremental untreated wastewater BOD5 loading reduction, and only limited incremental
costs for preparation of the BMP Plan and minor facility upgrades. For mills with
marginally adequate programs, EPA estimates that the average incremental untreated
wastewater BOD3 loading reduction will be about 2.5 kg/ADMT. For mills with inadequate
programs, the estimated average incremental untreated BOD5 loading reduction will be
about 5 kg/ADMT. For sulfite mills, EPA assigned effluent average loading reductions of
2.5 kg/ADMT for half of the mills, and 5 kg/ADMT for the other half of the mills. The
YRJ-0MS
0327-01.nq 9-10

9.0 Estimated Costs and Effluent Reduction Benefits
reduction in untreated wastewater BOD, loadings will, in turn, result in reduced effluent
loadings.
EPA's conclusions regarding spent pulping liquor management and BMP implementation
are as follows:
• Spent pulping liquor management and spill control systems, as well as spill
control systems for other chemicals such as turpentine and soap,are important
for economic operation of kraft pulping and recovery systems, for minimizing
adverse impacts on wastewater treatment systems, and for producing optimum
effluent quality. Such systems are essential for minimizing effluent discharges
from chemical pulp mills.
• Spent pulping liquor management and control systems are best implemented
through a combination of spent pulping liquor management systems and
operating practices (non-hardware) and spill collection and recovery systems
(hardware). Spill and loss prevention, rather than spill collection, is essential
for effective spent pulping liquor management.
• Approximately 26% of the bleached kraft and soda mills in the United States
have essentially complete- spent pulping liquor management and control
systems, approximately 29% have partial systems, and approximately 45%
would require major upgrades to fully implement effective control systems.
Sulfite mills in the United States are estimated to have a status similar to the
bleached kraft mills.
• Collection and recovery of kraft black liquor at liquor solids concentrations
of 3 to 4% will be cost-effective at most kraft mills. Consequently, emphasis
must be placed on collecting spent liquor at concentrations greater than 3 to
4%. Some mills collect and recover spent liquor at lower liquor solids
concentrations because of effluent color considerations. Evaporator hydraulic
capacity is likely to be a limiting factor that will prevent many mills from
recovering spent pulping liquor at low liquor solids concentrations.
• Two case studies show that for mills with few spent pulping liquor control
systems in place, liquor spill prevention and control can be cost-effective. The
return on investment may not be exceptionally high; however, substantial cost
savings could occur at mills where effective spent pulping liquor management
:vtu-M
0327-01.n4 9-11

9.0 Estimated Costs and Effluent Reduction Benefits
and spill control systems can be installed instead of effluent color treatment
systems or upgraded biological treatment systems.
• Additional benefits associated with effective spent pulping liquor management
that cannot be quantified include: a cleaner environment resulting from
reduced effluent discharges, reduced secondary environmental impacts
achieved through the use of recovered chemicals, and reduced risk of effluent
limitation exceedances.
v
utu-088
0327-0t.nq 9_12

9.0 Estimated Costs and Effluent Reduction Benefits
Table 9-1
BMP Implementation Status for Spent Pulping Liquor Control Systems at
Bleached Kraft Mills, Soda Mills, and Sulfite Mills
BMP Implementation Status
Number of Mills Number of Mills in Number of Mills
in Category 1 Category 2 in Category 3
Pulping Process (10% costs) (up to 60%costs) (up to 90%costs)
Bleached Kraft and Soda 22 25 37
Dissolving Kraft 1 0 2
Total 23 25 39
Papergrade Sulfite 3 3 5
Dissolving Sulfite 0 2 2
Total 3 5 7
Sources: EPAProjectFiles:Pulp,Paper and Paperboard Effluent Limitations Guidelines
NCASI, 1994 (23)
AF&PA, 1995 (24)
Ntu-0ss
0327-01.nq 9-13

9.0 Estimated Costs and Effluent Reduction Benefits
Table 9-2
BMP Investment Cost Estimates for Kraft Mills
Mill Complexity
EPA Model
BMP Technology Single Line Moderately Complex Complex
$ 750,000 $ 1,350,000 $ 1,800,000
Liquor Collection Sumps (up to 5 sumps) (up to 9 sumps) (up to 12 sumps)
Liquor Storage Capacity 600,000 60 ,000 600,000
(one 500,000-gallon tank)
150,000 300,000 300,000
Fiber Reclaim Tank(s) (one tank) (two tanks) (two tanks)
Process Area Curbing 200,000 300,000 400,000
and Diking
Turpentine and Soap 150,000 250,000 350,000
Containment
Sewer Conductivity Monitoring 150,000 250,000 350,000
and Storage Tank Alarms
Initial BMP Plan Preparation 150,000 200,000 250,000
and Initial Operator Training
Total $ 2,150,000 $ 3,250,000 $ 4,050,000
Source: EPA Project Files: Pulp, Paper and Paperboard Effluent Limitations Guidelines
n to-0Ba
0327-01.nq 9-14

9.0 Estimated Costs and Effluent Reduction Benefits
Table 9-3
BMP Investment Cost Estimates for Sulfite Mills
EPA Model BMP Technology Single Line
$ 450,000
Liquor Collection Sumps (up to 3 sumps)
Liquor Storage Capacity 300,000
(one 200,000-gallon tank)
150,000
Fiber Reclaim Tank
Process Area Curbing 150,000
and Diking
Sewer Conductivity Monitoring 100,000
and Storage Tank Alarms
Initial BMP Plan Preparation 150,000
and Initial Operator Training
Total $ 1,300,000
Note: All sulfite mills have a single fiber line.
Source: EPA Project Files: Pulp, Paper and Paperboard Effluent Limitations Guidelines
NRJ-088
0327-01.nr 9-15

9.0 Estimated Costs and Effluent Reduction Benefits
Table 9-4
Effects of Spent Pulping Liquor Control Systems on POTW Effluent Quality
at a Southern U.S. Kraft Mill Discharging to POTW
POTW Effluent 1988 1992 Percent
Characteristic FEMuent Quality Effluent Quality Change
Flow (m'/ADMT)
95th Percentile 154 140
Median 120 127 + 5.8
Mean 117 121 + 3.4
Standard Deviation 24.2 17.9
Coefficient of Variation 0.21 0.15 - 29
COD (kg/ADMT)
95th Percentile 54.7 41.1
Median 373 26.9 - 28
Mean 37.7 27.6 - 27
Standard Deviation 10.8 8.52
Coefficient of Variation 0.29 0.31 + 6.8
TSS (kg/ADMT)
95th Percentile 10.4 5.08
Median 5.11 2.15 - 58
Mean 5.61 2.41 - 57
Standard Deviation 2.93 1.30
Coefficient of Variation 0.52 0.54 + 3.8
BODS (kg/ADMT)
95th Percentile 4.23 3.65
Median 1.90 1.49 . 23
Mean 2.09 1.73 - 17
Standard Deviation 1.14 1.04
Coefficient of Variation 0.55 0.60 + 9.0
Source: EPA, 1993 (19)
NRJ-088
0327-Ol.nd 9-16

9.0 Estimated Costs and Effluent Reduction Benefits
Table 9-5
Quantified Effluent Reduction Benefits From Spent Pulping
Liquor Control System at a Kraft Mill Without Secondary Treatment
Effluent March July Percent
Characteristic 1982 1985 Reduction
Flow (m'/adt) 135 106 21 %
BOD (kg/adt) 40 29 27 %
TSS (kg/adt) 8.6 5.3 38
Dissolved 200 145 27 %
Solids (kg/adt)
Sodium 146 108 26 %
(kg
Na,SO,/adt)
Toxic 1,060 335 68 %
Contribution
(TV m'/adt)
Note: TU- Toxic units calculated as the reciprocal of the LC,using static bioassays multiplied by 100.
Toxic units were converted to toxic contribution in m'ladt by multiplying the toxic units by the flow
of the effluent and dividing by mill production. Bioassays were conducted using juvenile rainbow
trout (Salmo gairdneri).
Sources: Scroggins, 1986 (29)
Sikes and Almost, 1986 (30)
NRJ-088
0327-OLnn 9-17

9.0 Estimated Costs and Effluent Reduction Benefits
Figure 9-1
Effect of Spent Pulping Liquor Control Systems on POTW Effluent Flow at a Kraft Mill
200
b
M 150
3 100
aCi
- - 1988
W
50 ,' — 1992
O
0
0 20 40 60 80 100
Effluent Flow Distribution M
NIU4M
0327.01.nd 9-18

9.0 Estimated Costs and Effluent Reduction Benefits
Figure 9-2
Effect of Spent Pulping Liquor Control Systems on POTW Influent COD Levels at a Kraft Mill
400
ti
0 300 - - - 1988
Q --- 1992
Y
O
V 200
w
m
w
o 100
0 0 20 40 60 80 100
NIU-088
0327-01.nq 9-19

9.0 Estimated Costs and Effluent Reduction Benefits
Figure 9-3
Effect of Spent Pulping Liquor Control Systems on POTW Effluent COD Levels at a Kraft Mill
80
— -1988 /
60 — 1992 /
Q �
Q �
o,
V 40
w
aCi '
W �
a 20
0 0 20 40 60 80 10O
Effluent COD Distribution (°.61
NPJ4=
037/-01.nq 9-20

9.0 Estimated Costs and Effluent Reduction Benefits
Figure 9-4
Effect of Spent Pulping Liquor Control Systems on TSS Levels at a Kraft Mill
25
20
Q — - 1988
Q �
15 — 1992
Cn
� 1
10
W '
2 — '
O
5 _
i
0
0 20 40 60 80 100
Effluent TSS Distribution 1°4l
NRJ-0BB
0327-01.nj 9-21

9.0 Estimated Costs and Effluent Reduction Benefits
Figure 9-5
Effect of Spent Pulping Liquor Control Systems on BODS Levels at a Kraft Mill
8
p 6 — - 1988 /
Q
— 1992 /
to /
m4 /
C �
m �
ra i
W
2
Q
0
0 20 40 60 80 100
Effluent BOD5 Distribution (%l
NRJ-088
032MI,nq 9-22

9.0 Estimated Costs and Effluent Reduction Benefits
Figure 9-6
Effect of Spent Pulping Liquor Control Systems on a Turpentine Spill at a Kraft Mill
8
Weekly Average_NPDES Permit Limit
6
u�
— — — — — — — — — — — — — — — — — — — — - - — — —
m
c
3 4
W
Coo
i
Q 2
z
3
J F M A M J J A S O N D
NRJ-088
0327-01ni 9-23

References
1. Kringstad, KP. and K. Lindstrom. Spent Liquors from Pulp Bleaching.
Environmental Science and Technology, 18(8), 236A, 1984.
2. Springer, AM. Industrial Environmental Control - Pulp and-Paper Industry. John
Wiley and Sons, Inc. New York, New York, 1986.
3. Leach, J.M. and A.N. Thakore. Isolation of Toxic Constituents of Kraft Pulp Mill
Effluents. CPAR Report No. 11-4. Canadian Forest Service. Ottawa, Ontario, 1974.
4. Leach, J.M. and A.N. Thakore. Identification and Treatment of the Toxic Materials
in Mechanical Pulping Effluents. CPAR Report No. 149-2. Canadian Forest Service.
Ottawa, Ontario, 1974.
5. Development Document for Effluent Limitations Guidelines and Standards for the
Pulp, Paper and Paperboard Point Source Category. U.S. Environmental Protection
Agency. Washington, D.C., October 1982. (EPA 440/1-82/025) .
6. Statistics of Paper, Paperboard & Wood Pulp - 1993. American Forest and Paper
Association. Washington, D.C., September 1993.
7. 1990 National Census of the Pulp, Paper and Paperboard Manufacturing Facilities.
U.S. Environmental Protection Agency. Washington, D.C., 1990.
8. Smook, G.A. Handbook for Pulp and Paper Technologists. Joint Textbook
Committee of the Paper Industry. TAPPI, Technology Park, Atlanta, Georgia and
Canadian Pulp and Paper Association, Montreal, Canada, 1989.
9. Green, R.P. and G. Hough. Chemical Recovery in the Alkaline Pulping Process
(Third Edition). TAPPI Press. Atlanta, Georgia, 1992.
10. Libby, E.C. Pulp and Paper Science and Technology, Volume 1 - Pulp. Joint
Textbook Committee of the Paper Industry. McGraw-Hill Book Company. New
York, New York. 1962.
11. Ingruber, O.V., M.J. Kocurek, and A. Wong. Pulp and Paper Manufacture, Volume
4, Sulfite Science and Technology. Joint Textbook Committee of the Paper Industry.
TAPPI, Technology Park, Atlanta, Georgia, and CPPA, Montreal, Quebec, Canada,
1985.
12. NCASI. The Toxicity of Kraft Pulping Wastes to Typical Fish Food Organisms.
Technical Bulletin No. 10. National Council of the Paper Industry for Air and
Stream Improvement, Inc. New York, New York, May 1947.
NPJ-098
0327-01.nq Ref-1

References
13. NCASI. A Study of the Toxic Components of the Waters of Five Typical Kraft Mills.
Technical Bulletin No. 16. National Council, of the Paper Industry for Air and
Stream Improvement, Inc. New York, New York. April 1948.
14. NCASI. The Effects of Kraft Mill Waste liquors and Some of Their Components on
Certain Salmonid Fishes of the Pacific Northwest. Technical Bulletin No. 51.
National Council of the Paper Industry for Air and Stream Improvement, Inc. New
York, New York, May 1952,
15. McKee, J.E., and H.W. Wolf. Water Quality Criteria, Second Edition,Publication 3-
A. The.Resources Agency of California, State Water Resources Control Board.
Sacramento, California, February 1963 (Reprint December 1971).
16. Scroggins, R.P. In-Plant Toxicity Balances for a Bleached Kraft Pulp Mill. Pulp &
Paper Canada 87(9): T344-348, September 1986.
17. Kleyhans, C.J., G.W. Schulz, J.S. Engelbrecht, and R.J. Rousseau. The Impact of a
Paper Mill Effluent Spill on the Fish Populations of the Elands and Crocodile Rivers
(Incomati System, Transvaal). ISSN 0378-4738=Water SA, Vol. 18, No. 2, April
1992.
18. Fox, M.E. Dehydroabietic Acid Accumulation by Rainbow Trout (Salmo gairdneri)
Exposed to Kraft Mill Effluent. Journal of Great Lakes Research, 3:155-161, 1977.
19. EPA Region 4 File Information, 1993.
20. U.S. EPA Emergency Response Notification System (ERNS): Data reported for the
period January 1988 to March 1993. U.S. Environmental Protection Agency,
Washington, D.C., 1993.
21. NCASL Spill Prevention and Control Aspects' of Paper Industry Wastewater
Management Programs. Technical Bulletin No. 276. National Council of the Paper
Industry for Air and Stream Improvement, Inc. New York, New York, August 1974.
22. NCASI. Chemical Specific Information - SARA Section 313 Reporting. National
Council of the Paper Industry for Air and Stream Improvement, Inc. Gainesville,
Florida, March 1989.
23. BMP Questionnaire. National Council of the Paper Industry for Air and Stream
Improvement, Inc. Medford, Massachusetts, November 1994.
NPJ-088
0327-01.nq Ref-2

References
24. Personal Communication from Catherine A. Marshall, Director, Environmental
Affairs, American Forest & Paper Association, Washington, D.C. to Ronald P.
Jordan, Engineering and Analysis Division, Environmental Engineer, U.S.
Environmental Protection Agency, Washington, D.C., September 8, 1995.
25. Personal Communication from Virginia C.Holton,Regional Environmental Manager,
Packaging Corporation of America, Valdosta, Georgia to Ronald P. Jordan,
Environmental Engineer, U.S. Environmental Protection Agency, Washington, D.C.,
September 8, 1995.
26. Personal Communication from Danforth Bodien, U.S. Environmental Protection
Agency, Region W, Seattle, Washington to Gary Amendola, Amendola Engineering,
Lakewood, Ohio, March 1995.
27. Personal Communication from Neil MCCubbin,N.McCubbin Consultants Inc.,Foster
Quebec to Gary Amendola, Amendola Engineering, Lakewood, Ohio, November
1995.
28. Personal Communication from J. Floyd Byrd, Lawrenceburg, Indiana to Gary
Amendola, Amendola Engineering, Lakewood, Ohio, August 31, 1992.
29. Scroggins, R.P. In-Plant Toxicity Balances for a Bleached Kraft Pulp Mill. Pulp &
Paper Canada 87(9): T344-348, September 1986.
30. Sikes, J.E.G. and S. Almost. Black Liquor Spill Control at Terrace Bay. Pulp &
Paper Canada, 87(12):T496-500, December 1986.
Nw-08
0327-01.nq Ref-3

ATTACHMENT A
BEST MANAGEMENT PRACTICES REGULATION

40 CFR Part 430.03
THE PULP, PAPER, AND PAPERBOARD POINT SOURCE CATEGORY
§430.03 Best management practices plans for spent pulping liquor management, spill
prevention, and control
(a) Applicability
The provisions of this part are applicable to direct and indirect discharge pulp,paper
and paperboard mills with pulp production in Subparts B (Bleached Papergrade Kraft and
Soda) and E (Papergrade Sulfite).
(b) Specialized Definitions
(1) Board of Review: A meeting among process operators,maintenance personnel,
process engineering personnel, environmental control staff and representatives of mill
management conducted as soon as practicable after a spill or intentional diversion of spent
pulping liquor that is not contained within the immediate process area. The purpose of the
board of review is to review the circumstances leading to the incident, to review the
effectiveness of the corrective actions taken, and to develop changes to equipment and
operating and maintenance practices to prevent recurrence.
(2) Immediate Process Area: The location at the mill where pulping, screening,
knotting, pulp washing, pulping liquor concentration or processing and chemical recovery
facilities are located, generally the battery limits of the aforementioned processes.
"Immediate process area" includes spent pulping liquor storage and.spill control tanks
located at the mill, whether or not they are located in the immediate process area.
(3) Spent Pulping Liquor: For kraft and soda mills "spent pulping liquor' shall
mean black liquor that is used, generated, stored or processed at any point in the kraft
pulping and chemical recovery processes. For sulfite mills "spent pulping liquor' shall mean
any intermediate,final or used chemical solution that is used,generated,stored or processed
at any point in the sulfite pulping and chemical recovery processes (e.g., ammonium,
calcium, magnesium and sodium base sulfite liquors).
NRJ-088
0327-01.nj

(4) Equipment in Spent Pulping Liquor Service: Any process vessel, storage
tank, pumping system, evaporator, heat exchanger, recovery furnace or boiler, pipeline,
valve, fitting, or other device that contains,processes, transports, or comes into contact with
spent pulping liquor.
(5) Interference: "Interference" shall have the meaning set out at §403.3.
(6) Pass Through: "Pass through" shall have the meaning set out at §403.3.
(7) Senior Technical Manager: The person designated by the mill manager to
review and certify the BMP Plan. The senior technical manager may be the chief engineer
at the mill or the manager of pulping and chemical recovery operations, or other such
responsible person designated by the mill manager.
(c) Preparation, Certification and Review of BMP Plan
(1) Owners or operators of pulp,paper, or paperboard mills with pulp production
in Subparts B or E shall prepare and implement a Best Management Practices Plan,
hereafter referred to as "BMP Plan," for each such mill. The BMP Plan shall contain the
elements set out in, and be prepared and implemented in accordance with, §430.03(d), (e)
and (f).
(2) Schedules for Preparing BMP Plans
(A) Indirect Dischargers. Owners and operators of indirect discharging mills
subject to this section shall prepare BMP Plans not later than [insert date six months after
promulgation].
(B) Direct Dischargers. Each NPDES permit for mills subject to this section
issued after [insert date of promulgation] shall include the requirements imposed by this
section. Owners and operators of direct discharging mills subject to this section shall
prepare BMP Plans by the date specified in the NPDES permit conditions imposing these
requirements, or not later than [insert date six months after promulgation], whichever is
later.
(C) New Sources. Notwithstanding the compliance schedules authorized in (A)
and (B) above, owners or operators of new sources subject to this section shall develop BMP
Plans, and these plans shall be implemented upon commencement of discharging.
NRJ-088
0327-01.nq A-2 .

(3) Not later than 30 days after preparation of the initial BMP Plan required by
this part, the owner or operator shall certify to the NPDES permit or pretreatment
authority, as appropriate, that the BMP Plan has been prepared. The owner or operator
shall notify the NPDES permit or pretreatment authority each time the BMP Plan has been
reviewed and/or amended in accordance with this part. Such notification shall be reported
not later than 30 days from completion or the modification. The owner or operator shall
maintain, at the mill to which the BMP Plan applies, a current copy of the BMP Plan and
supporting records available for review by the Regional Administrator or his designee during
normal business hours.
(4) The owner or operator shall not be required to obtain approval of the initial
BMP Plan required by this part, or subsequent amendments thereto, from the NPDES
permit or pretreatment authority; however, in the event of spills of spent pulping liquor,
turpentine or soap to navigable waters, or in the event of upset of privately-owned or
publicly-owned treatment works to the extent any effluent limitation or discharge prohibition
is exceeded, or to the point where "interference" or "pass through" at a publicly-owned
treatment works occurs, the NPDES permit or pretreatment authority, at its discretion, may
conduct a review of the BMP Plan and implementation of the BMP Plan by the owner or
operator as part of any compliance or enforcement proceeding.
(d) Objectives and Key Elements of the BMP Plan
The primary objective of the BMP Plan shall be to prevent losses and spills of spent
pulping liquors from equipment items in pulping liquor service, and to prevent losses and
spills of soap and turpentine. The secondary objective shall be to contain, collect, and
recover at the immediate process area, or otherwise control, those spills and losses of spent
pulping liquor, soap and turpentine that do occur.
The BMP Plan shall contain the following key elements:
(1) approval by the mill manager;
(2) engineering analyses,
(3) engineered controls and containment,
(4) work practices,
(5) preventive maintenance,
Nm-0as
0327-01."q A-3

(6) dedicated monitoring and alarm systems,
(7) surveillance and repair programs,
(8) employee training, and
(9) continuous wastewater treatment influent monitoring and tracking program.
(e) Preparation of the BMP Plan
The BMP Plan shall be prepared in accordance with good engineering practice. If
the initial BMP Plan calls for additional management practices, facilities or procedures,
methods, or equipment not fully operational, the details of the installation and the
operational startup should be explained. The complete BMP Plan shall contain the
elements described below:
(1) The BMP Plan shall be certified by the senior technical manager at the mill
and approved and signed by the mill manager.
(2) A detailed engineering review of the pulping and chemical recovery
operations, including but not limited to process equipment, storage tanks, pipelines and
pumping systems, loading and unloading facilities, and other appurtenant pulping and
chemical recovery equipment items in spent pulping liquor, turpentine and soap service, to
determine the magnitude and routing of potential leaks, spills and intentional diversions of
spent pulping liquors during the following periods of operation:
(i) process startups and shutdowns;
(ii) maintenance;
(iii) grade changes;
(iv) storm events;
(v) power failures; and
(vi) normal operations.
(3) A detailed engineering review of existing spent pulping liquor containment
facilities for the purpose of determining whether there is adequate capacity for collection
and storage of anticipated intentional liquor diversions with sufficient contingency for
collection and containment of spills, based upon good engineering practice. Secondary
containment(containment constructed of materials impervious to pulping liquors)equivalent
to the volume of the largest tank plus sufficient freeboard for precipitation should be
provided for bulk storage tanks. In lieu of secondary containment for bulk storage tanks,
vw-osa
0327-01.nn A-4

the owner or operator may elect to substitute a periodic tank integrity testing program and
other containment or diversion structures. The engineering review shall also consider the
need for process wastewater diversion facilities to protect end-of-pipe wastewater treatment
facilities from adverse effects of spills and diversions of spent pulping liquors; the potential
for contamination of storm water from the immediate process areas; and, the extent to
which segregation and/or collection and treatment of contaminated storm water from the
immediate process areas is appropriate.
(4) Secondary containment shall be provided for bulk turpentine storage tanks.
Curbing and/or diking or other means of isolating soap and turpentine processing areas
from the wastewater treatment facilities shall be provided.
(5) Development and implementation of preventive maintenance practices,
standard operating procedures, work practices, engineered controls and monitoring systems
to prevent spent pulping liquor losses and to divert spent pulping liquors to containment
facilities such that the diverted or spilled liquors may be returned to the process to the
maximum extent feasible as determined by the owner or operator, or metered to the
wastewater treatment system.
(6) A program of regular visual inspections (e.g., at least once per operating shift
or once per day) of equipment items in spent pulping liquor service and a program for
repair of leaking equipment items. The repair program shall encompass immediate repairs
when possible, and identification for repair during the next maintenance outage those
leaking equipment items that cannot be repaired during normal operations. The owner or
operator of the mill shall also establish conditions under which production will be curtailed
or halted to repair leaking equipment items or prevent liquor losses. The repair program
shall include tracking repairs over time to identify those equipment items where upgrade or
replacement may be warranted based upon frequency and severity of leaks or failures. The
owner or operator shall maintain logs showing the date spent pulping liquor leaks were
detected, the type of spent pulping liquor spilled or leaked (e.g., weak black liquor,
intermediate black liquor, strong black liquor), an estimate of the magnitude of the spill or
leak, the date of first attempt at repair, and the date of final repair. The logs shall be
NRJ-098
032MI.nq A-5

maintained at the mill for a period of three years for review by the Regional Administrator
or his designee during normal working hours.
(7) A program of initial and refresher training of operators, maintenance
personnel, and other technical and supervisory personnel who have responsibility for
operating, maintaining or supervising the operation and maintenance of equipment items
and systems in spent pulping liquor service. The refresher training shall be conducted
annually(once per calendar year). The training shall be documented and records of training
shall be maintained at the mill for review by the Regional Administrator or his designee
during normal working hours. The records of initial and annual refresher training shall be
maintained for a period of three years for review by the Regional Administrator or his
designee during normal working hours.
(8) A program of 'boards of review' to evaluate each spill not contained at the
immediate process area and any intentional diversion of spent pulping liquor not contained
in the immediate process area. The boards of review shall be conducted as soon as
practicable after the event and shall be attended, to the extent practicable, by the involved
process operators or their immediate supervisors, maintenance personnel, process
engineering personnel, environmental control staff and representatives of mill management.
A brief report shall be prepared for each board of review. The report shall describe the
equipment items involved, the circumstances leading to the incident, the effectiveness of the
corrective actions taken to contain and recover the spill or intentional diversion, and plans
to develop changes to equipment and operating and maintenance practices to prevent
recurrence. Summaries of the boards of review shall be included as part of the annual
refresher training. The reports of boards of review shall be maintained at the null site for
a period of three years for inspection by the Regional Administrator or his designee.
(9) A program to review any planned modifications to the pulping and chemical
recovery facilities and any construction activities in the pulping and chemical recovery areas
before these activities commence. The purpose of the reviews shall be to ensure that spent
pulping liquor spill prevention and control is considered as part of the planned
modifications, and that construction and supervisory personnel are aware of possible liquor
diversions and the potential for spills of spent pulping liquors during construction.
YRJ-W
0327-01.nd A-6

(10) The owner or operator shall conduct daily 24-hour composite monitoring of
the influent and effluent of the wastewater treatment system for Chemical Oxygen Demand
(COD), Total Organic Carbon (TOC), or other short-term measure of organic content that
can be completed on a daily basis. For indirect dischargers, monitoring shall be conducted
of the pulp and paper mill effluent discharged to the POTW prior to mixing with
wastewaters from other sources. Not later than six months after certification of the BMP
Plan by the senior technical manager, the owner or operator shall establish upper control
limits for wastewater treatment system influent mass loadings of COD, TOC, or other
measure of organic content. Such upper control limits shall be based on the 75th percentile
and 90th percentile of the seven-day running average wastewater treatment system influent
mass loadings. Whenever the seven-day running average influent mass loading exceeds the
75th percentile upper control limit, the owner or operator shall initiate an investigation to
determine the cause of such occurrence, and initiate corrective action as appropriate.
Whenever the 90th percentile upper control limit is exceeded, the owner or operator shall
initiate corrective action to bring the wastewater treatment system influent mass loading
below the established upper control limits.
Not later than nine months after implementation of the BMP Plan (including
construction of any new spent pulping liquor collection and/or control systems), the owner
or operator shall establish new 75th percentile and 90th percentile upper control limits, and
conduct monitoring of COD, TOC or other measure of organic content; and conduct
investigative and corrective actions as described above.
During the term of the NPDES permit or pretreatment permit, the owner or
operator shall report to the NPDES permit or pretreatment authority on a quarterly basis
the results of the monitoring program for COD, TOC or other measure of organic content.
The report shall include daily wastewater treatment system influent and effluent
concentrations and mass discharges, the established or revised 75th percentile and 90th
percentile upper control limits, and the running seven-day average wastewater treatment
system influent mass loadings. The report shall also include brief narrative descriptions of
any corrective actions taken to respond to exceedances of the 90th percentile upper control
limit. Exceedances of the wastewater treatment system influent upper control limits shall
`x3-0sa
0327-01.nq A-7

not be considered violations of the NPDES or pretreatment permit. Failure to respond to
an exceedance of the 90th percentile upper control limits may constitute a violation of the
NPDES or pretreatment permit.
(f) Schedules for Implementing BMPs Specified in BMP Plans
(1) Indirect Dischargers. Indirect dischargers subject to this section shall
implement the BMPs specified in their BMP Plans no later than dates set forth below:
(A) Construction of any pulping liquor collection, containment or diversion
facilities necessary to fully implement the BMP Plan -- [insert date 36 months after
promulgation]
(B) Installation or upgrade of any continuous, automatic monitoring systems
necessary to fully implement the BMP Plan, including but not limited to, high level monitors
and alarms on existing storage tanks, process area conductivity (or pH) monitoring and
alarms, and process area sewer, process wastewater, and wastewater treatment plant
conductivity (or pH) monitoring and alarms, not later than [insert date 24 months after
promulgation].
(C) Commence implementation of all other aspects of the BMP Plan not later
than [insert date 6 months after promulgation].
(D) Establish initial upper control limits not later than [insert date 6 months after
date of promulgation].
(E) Establish revised upper control limits as soon as possible after preparation of
BMP Plan, but not later than [insert date 45 months after date of promulgation].
(2) Direct dischargers. Owners and operators of direct discharging mills subject
to this section shall implement their BMP Plans by the date on which the NPDES permit
conditions imposing these BMP requirements are issued or in accordance with the deadlines
set forth in (1) above, whichever is later. If a deadline for implementing certain BMPs set
forth in (1) above has passed at the time the permit containing the BMP requirements is
issued, the permit shall require immediate implementation of those BMPs.
(3) New Sources. Notwithstanding the compliance schedules authorized in(1)and
(2) above, owners or operators of new sources shall implement all of the BMPs specified
in their BMP Plans upon commencing discharge, except that upper control limits from
Nw-0sa
0329-01.nd A-8

paragraph (e)(10) shall be established not later than [insert date 12 months after
promulgation], based upon the prior six months of monitoring data.
(g) Review and Certification of BMP Plan
No BMP Plan shall be effective to satisfy the requirements of this part unless it has
been reviewed by the senior technical manager at the mill, certified to by such senior
technical manager, and approved by the mill manager. By means of this certification, the
senior technical manager, having examined the mill and being familiar with the provisions
of this part, shall attest that the BMP Plan has been prepared in accordance with good
engineering practices. Such certification shall in no way relieve the owner or operator of
the mill of the obligation to prepare and fully implement the BMP Plan in accordance with
§430.03(e), as required by paragraph (a) of this section.
(h) Review of BMP Plan by NPDES Permit or Pretreatment Authority
The owner or operator of a mill for which a BMP Plan is required by paragraph (a)
of this section shall maintain a complete copy of the plan and associated records of
implementation as required by this section at such mill at all times and shall make such plan
available to the Regional Administrator or his designee for on-site review during normal
working hours or off-site review upon request.
(i) Amendment of BMP Plan
(1) The owner or operator of a mill subject to §430.03 shall amend the BMP Plan
for such mill in accordance with §430.03(e) whenever there is a change in mill design,
construction, operation or maintenance which materially affects the potential for spills or
losses of spent pulping liquor from the immediate process areas.
(2) Notwithstanding paragraph (h)(1) of this section, the owner or operator of a
mill subject to §430.03 shall complete a review and evaluation of the BMP Plan at least
once every three years from the date such mill becomes subject to this part. As a result of
this review and evaluation, the owner or operator shall amend the BMP Plan within three
months of the review to include any management practices or technologies that would
significantly reduce the likelihood of spent pulping liquor spills and losses from the
immediate process areas.
NRJ-0Sd
0327-01.nq A-9

(3) No amendment to a BMP Plan shall be effective to satisfy the requirements
of this section unless it has been certified by the senior technical manager at the mill and
approved by the mill manager in accordance with §430.03(e).
NRM88
0327-01.nq A-10

Attachment A
40 CFR Part 430.03 - Best Management Practices
Summary of Regulatory Provisions and Changes from Proposed Regulation
Regulatory Provision Draft Final Regulation Proposed Regulation Comments
Applicability Subpart B-13.1. Papergrade Kraft & Soda Subpart A - Dissolving Kraft Final regulation will apply only to Subparts A
Subpart E - Papergrade Sulfite Subpart B-Bl. Papergrade Kraft & Soda and B (subcategories where BAT effluent
Subpart C - Unbleached Kraft limitations guidelines are being promulgated).
Subpart D - Dissolving Sulfite BMPs for other Subparts to be addressed in
Subpart E - Papergrade Sulfite subsequent regulations.
Subpart F - Semi-Chemical
Subpart H - Non-Wood Chemical Pulp
Materials regulated Spent pulping liquors (black liquors at All pulping liquors (green, white and Final regulation focused on spent pulping
kraft and soda mills; all used pulping black liquors at kraft and soda mills; liquors, turpentine and soap as materials with
liquors at sulfite mills) all intermediate, fresh and spent toxic components. Turpentine and soap were
Turpentine pulping liquors at other mills) added because these materials, if spilled or
Soap lost, can adversely affect wastewater
treatment operations and lead to increased
discharges of toxic and conventional
pollutants.
BMP Plan elements Approval of mill management Approval of mill management Changes from proposed regulation include:
Engineering analyses Engineering analyses
Secondary containment for turpentine Secondary containment for bulk liquor (1) modification of secondary containment
storage tanks only; tank integrity storage tanks; process area curbing provisions to allow for substitution of tank
testing may be substituted for liquor and diking integrity testing in place of secondary
tanks Preventive maintenance, work practices, containment for bulk liquor storage tanks;
Preventive maintenance, work practices, SOPS, engineered controls, and
SOPS, engineered controls, and monitoring and alarm systems (2) requirement for secondary containment
monitoring and alarm systems Visual inspection and repair programs for turpentine storage tanks and process area
Visual inspection and repair programs Initial and refresher employee training curbing and diking for turpentine processing
Initial and refresher employee training Boards of review for spills or losses not and soap processing and storage areas; and
Boards of review for spills or losses not contained with immediate process
contained with immediate process areas - (3) continuous monitoring and tracking of
areas Pre-construction review wastewater treatment system influent COD,
Continuous monitoring program Implementation schedule or other measure of organic loading, for early
Pre-construction review warning and tracking BMP Plan progress.
Implementation schedule
NRl-M
0327-01.nry A-11

Attachment A
(Continued)
Regulatory Provision Draft Final Regulation Proposed Regulation Comments
BMP Plan preparation Certified by senior technical manager Certified by registered professional Final regulation provides flexibility for BMP
Approved by mill manager engine: Plan certification.
Approved by mill manager
Implementation of BMP Indirect dischargers - through regulation Implemented through regulation Final regulation provides more specific
Direct dischargers - through regulation requirements regarding schedules.
or NPDES permits, depending upon
timing of permit issuance
New Sources - through NPDES permits
Compliance schedules Plan preparation Plan Preparation Final regulation provides more time for
Indirect dischargers - 180 days after Direct and Indirect dischargers - 120 preparation of initial BMP Plan and ,
promulgation days from date of promulgation installation of monitoring and alarm systems.
Direct dischargers - schedule in New Sources - prior to discharging
NPDES permit; compliance upon
issuance of permit for deadlines past Plan Implementation
at time of issuance Direct and Indirect dischargers - not 0
New Sources - available upon later than 18 months for monitoring,
commencing discharge alarms, etc.; not later than 36 months
for full BMPs
Plan Implementation
Indirect dischargers - not later than 6
months for initial upper control limits;
not later than 24 months for
monitoring, alarms, etc.; not later than
36 months for full BMPs; not later
than 45 months for final upper control
limits
Direct dischargers - schedule in
NPDES permit; compliance upon
issuance for deadlines past at time of
issuance
New Sources - implementation upon
commencement of discharges; not
later than 12 months for upper
control limits
N RJ-088
0127-01-a[ A-12