United States Office of Water EPA821-R-97-015
Environmental Protection 4303 October 1997
Agency
Technical Support Document
for Best Management Practices for
Spent Pulping Liquor Management,
Spill Prevention, and Control
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Technical Support Document for
Best Management Practices for
Spent Pulping Liquor Management,
Spill Prevention, and Control
U.S. Environmental Protection Agency
Office of Science and Technology
Engineering and Analysis Division
401 M Street, S.W.
Washington, D.C. 20460
October 1997
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DISCLAIMER
This report has been reviewed and approved for publication by the Engineering
and Analysis Division, Office of Science and Technology. This report was prepared with the
support of Eastern Research Group, Inc. (Contract No. 68-C5-0013) under the direction and
review of the Office of Science and Technology. Neither the United States Government nor
any of its employees, contractors, subcontractors, or their employees make any warrant,
expressed or implied, or assumes any legal liability or responsibility for any third party's use
of or the results of such use of any information, apparatus, product, or process discussed in
this report, or represents that its use by such party would not infringe on privately owned
rights.
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TECHNICAL SUPPORT DOCUMENT
FOR
BEST MANAGEMENT PRACTICES FOR
SPENT PULPING LIQUOR MANAGEMENT, SPILL PREVENTION, AND CONTROL
TABLE OF CONTENTS
Page
SPECIALIZED DEFINITIONS ; . . . viii
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_i
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 4.7
5.0 COMPOSITION AND TOXICITY OF PULPING LIQUORS, SOAP, AND
TURPENTINE 5.1
5.1 Kraft Mill Black Liquor 5-1
5.2 Sulfite Pulping Liquors (Red Liquors) 5-2
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 5-5
5.6 Toxic and Hazardous Pollutants Found in Turpentine and
Soap 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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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 7-4
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 8-8
8.2.1 Applicability of BMP Regulation to Pulping
Liquors Other Than Spent Pulping Liquor 8-9
8.2.2 Requirements for Specific BMP Equipment Items 8-9
8.2.3 Costs of BMP Compliance 8-9
8.2.4 Recovery of Liquor Solids Under BMP Regulation 8-9
8.2.5 Monitoring of BMP Implementation 8-10
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 Papergrade Kraft Mill 9-5
9.3.2 Canadian Bleached Papergrade Kraft Mill 9-7
9.4 General Conclusions ..-...' 9-9
10.0 REFERENCES 10-1
Attachment A: BEST MANAGEMENT PRACTICES REGULATION
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LIST OF TABLES
Page
3-1 Extractive Compounds Associated with Wood Pulping
Operations 3-3
4-1 Comparison of Kraft and Sulfite Pulping Processes . . . 4-8
5-1 Inorganic Content of Black Liquors (Weight Percent, Dry Solids
Basis) , . . . 5-9
5-2 Components in Black Liquors (Weight Percent, Dry Solids ;
Basis) 5-10
5-3 Composition of Calcium Base and Magnesium Base Sulfite
Pulping Liquors i ... 5-11
5-4 ' Composition of Ammonia Base and Sodium Base Sulfite Pulping
Liquors ; . . 5-12
5-5 Composition of Typical Fresh NSSC Pulping Liquors j . . 5-13
5-6 Composition of Typical Spent NSSC Pulping Liquors 5-14
5-7 Minimum Lethal Concentrations to Daphnia and Fathead >
Minnows of Components of Kraft Pulp Mill Wastewaters . 5-15
5-8 Critical Concentrations (Minimum Lethal Doses) to Fish of
Components of Sulfate (Kraft) Liquors . 5-16
5-9 Toxic Wastewater Pollutants and Hazardous Air Pollutants Found
in Spent Pulping Liquors . 5-17
5-10 Major Components Found in Kraft Condensate Prior to
Separation of Turpentine . 5-19
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 a Typical
Bleached Kraft Mill 6-7
IV
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LIST OF TABLES (Continued)
Page
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 (%) 7-10
7-2 Pulping Liquor Storage Capacity - Sulfite Mills Tank Volume
(Gallons) and Typical Operating Level (%) 7-11
9-1 BMP Implementation Status for Spent Pulping Liquor Control
Systems at Bleached Kraft and Soda Mills, and Sulfite Mills 9-12
9-2 BMP Investment Cost Estimates for Bleached Papergrade Kraft
and Soda Mills 9-13
9-3 BMP Investment Cost Estimates for Papergrade Sulfite Mills . 9-14
9-4 Effects of Spent Pulping Liquor Control Systems on POTW
Effluent Quality at a Southern U.S. Bleached Papergrade Kraft
Mill Discharging to POTW 9-15
9-5 Quantified Effluent Reduction Benefits From Spent Pulping
Liquor Control System at a Kraft Mill Without Secondary
Treatment . 9-16
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LIST OF FIGURES
Page
4-1 Kraft Process Simplified Schematic Diagram '-,. . . . 4-9
4-2 Kraft Pulping and Chemical Recovery Simplified Schematic
Diagram 4-10
4-3 Ammonia Base Sulfite Pulping Simplified Schematic Diagram 4-11
4-4 Calcium Base Sulfite Pulping Simplified Schematic Diagram 4-12
4-5 Sodium Base Sulfite Pulping Simplified Schematic Diagram 4-13
4-6 Magnesium Base Sulfite Pulping Simplified Schematic Diagram ...... 4-14
4-7 Sulfite Recovery Systems Currently in Use '. . . 4-15
4-8 Semi-Chemical Pulping Mill Utilizing Continuous Digestion
Simplified Schematic Diagram . . . i . . 4-16
4-9 Fluidized Bed System For Treatment of NSSC Waste Liquor ;
Simplified Schematic Diagram 4-17
7-1 Black Liquor Solids vs. Conductivity 7-12
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8-1 Wastewater Treatment Influent COD Levels With and Without
BMPs 8-14
9-1 Effect of Spent Pulping Liquor Control Systems on POTW
Effluent Flow at a Kraft Mill '. . . 9-17
9-2 Effect of Spent Pulping Liquor Control Systems on POTW
Influent COD Levels at a Kraft Mill 9-18
9-3 Effect of Spent Pulping Liquor Control Systems on POTW ;
Effluent COD Levels at a Kraft Mill 9-19
9-4 Effect of Spent Pulping Liquor Control Systems on TSS Levels
at a Kraft Mill 9-20
9-5 Effect of Spent Pulping Liquor Control Systems on BOD5
Levels at a Kraft Mill 9-21
9-6 Effect of a Major Turpentine Spill at a Kraft Mill on Effluent
BOD5 9-22
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SPECIALIZED DEFINITIONS
(1) Action Level: A daily pollutant loading that when exceeded triggers
investigative or corrective action. Mills determine action levels by a
statistical analysis of six-months of daily measurements collected at the
mill. For example, the lower action level may be the 75th percentile of
the running seven-day averages (that value exceeded by 25 percent of
the running seven-day averages) and the upper action level may be the
90th percentile of the running seven-day averages (that value exceeded
by 10 percent of the running seven-day averages).
(2) Equipment Items in Spent Pulping Liquor, Soap, and Turpentine
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, soap, or turpentine. Sometimes referred to as
"equipment items."
(3) Immediate Process Area: The location at the mill where pulping,
screening, knotting, pulp washing, pulping liquor concentration, pulping
liquor 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.
(4) Intentional Diversion: The planned removal of spent pulping liquor,
soap, or turpentine from equipment items in spent pulping liquor, soap,
or turpentine service by the mill for any purpose including, but not
limited to, maintenance, grade changes, or process shutdowns.
(5) Mill: The owner or operator of a direct or indirect discharging pulp,
paper, or paperboard manufacturing facility.
(6) Senior Technical Manager: The person designated by the mill manager
to review the BMP Plan. The senior technical manager shall be the
chief engineer at the mill, the manager of pulping and chemical
recovery operations, or other such responsible person designated by the
mill manager who has knowledge of and responsibility for pulping and
chemical recovery operations.
(7) Soap: The product of reaction between the alkali in kraft pulping liquor
and fatty acid portions of the wood, which precipitate out when water is
evaporated from the spent pulping liquor.
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(8) Spent Pulping Liquor. For kraft and soda mills "spent pulping liquor" '^.
means black liquor that is used, generated, stored, or processed at any MB
point in the pulping and chemical recovery processes. For sulfite mills ^^
"spent pulping liquor" means 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).
(9) Turpentine: A mixture of terpenes, principally pinene, obtained by the
steam distillation of pine gum recovered from the condensation of
digester relief gases from the cooking of softwoods by the kraft pulping
process. Sometimes referred to as sulfate turpentine.
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TECHNICAL SUPPORT DOCUMENT
FOR
BEST MANAGEMENT PRACTICES FOR
SPENT PULPING LIQUOR MANAGEMENT, SPILL PREVENTION, AND CONTROL
1.0 INTRODUCTION
This document presents information for Best Management Practices (BMPs) for bleached
papergrade kraft and soda, and papergrade sulfite mills. EPA promulgated these BMPs
pursuant to section 304(e), section 307(b) and (c), section 402(a), and section 501 (a) of the
Clean Water Act (CWA) for mills subject to 40 CFR Part 430, Subpart B - Bleached
Papergrade Kraft and Soda, and Subpart E - Papergrade Sulfite.
The BMPs establish controls that will reduce the release of toxic, conventional, and non-
conventional pollutants to navigable waters. The principal objective of the BMPs is to
prevent losses and spills of spent pulping liquor (also referred to as "black liquor" at kraft
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mills) from equipment items in pulping liquor service; the secondary objective is to contain,
collect, and recover, or otherwise control, spills, losses and intentional liquor diversions that
do occur. The BMPs also apply 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 (e.g., kraft
black liquor and 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 EPA's Emergency Response Notification System shows that only a
few pulping liquor spills have resulted from catastrophic failures of bulk liquor storage tanks.
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1.0 Introduction ^^
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. In addition, mill operators intentionally divert pulping liquors from the
process during certain maintenance operations and during process start-ups and shut, downs
(20).
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 minimized. 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.
These BMPs focus on controlling spent pulping liquor losses and intentional liquor diversions
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 are a significant contribution to untreated
wastewater loadings and discharge loadings of color, oxygen-demanding
substances, and non-chlorinated toxic compounds from chemical pulp
mills. ;
(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
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1.0 Introduction
from kraft mills and volatile hazardous air pollutants (HAPs) from all
chemical pulp mills implementing these BMPs.
This document presents information on BMPs for controlling losses of spent pulping liquor,
soap and turpentine. Section 2.0 summarizes EPA's legal authority to promulgate BMP
requirements. 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, soap and turpentine are described in Section 5.0. Sources of
pulping liquor losses are described in Section 6.0. Current industry practices regarding spent
pulping liquor management, spill prevention, and control are reviewed in Section 7.0, along
with discussion of spill containment measures for soap and turpentine. The BMP
requirements are described hi Section 8.0. Estimated costs, effluent reduction benefits, and
current industry status with respect to implementing BMPs are presented in Section 9.0.
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2.0 LEGAL AUTHORITY
In the BMP regulation codified at 40 CFR 430.03, EPA is requiring mills with pulp
production in the Bleached Papergrade Kraft and Soda Subcategory (Subpart B) and the
Papergrade Sulfite Subcategory (Subpart E) to implement BMPs to prevent or otherwise
contain leaks and spills and to control intentional diversions of spent pulping liquor, soap, and
turpentine. These BMPs apply to direct and indirect discharging mills within these
subcategories and are intended to reduce wastewater loadings of non-chlorinated toxic
compounds and hazardous substances. The same BMPs will also remove, as an incidental
matter, significant loadings of color and certain oxygen-demanding substances in pulping
liquors that are not readily degraded by biological treatment. EPA also expects incidental
reductions in conventional water pollutants and certain air pollutants as a result of the BMPs.
EPA's legal authority to promulgate this BMP regulation is found in Section 304(e), Section
307(b) and (c), Section 308(a), Section 402(a)(l)(B), Section 402(a)(2) and Section 501 (a) of
the Clean Water Act, 33 U.S.C. § 1251, et seq. EPA also relies on 40 C.F.R. § 122.44(k).
This BMP regulation is also consistent with the Pollution Prevention Act of 1990, 42 U.S.C. §
13101, et seq.
For authority to impose BMPs on direct discharges, EPA relies in part on section 304(e) of
the Clean Water Act. EPA is authorized under section 304(e) to publish regulations on a
categorical basis for certain toxic or hazardous pollutants for the purpose of controlling plant
site runoff, spillage or leaks, sludge or waste disposal, and drainage from raw material
storage, when the Administrator determines (1) that such incidents are associated with or
ancillary to the industrial manufacturing or treatment process of point sources within the class
or category, and (2) that the incidents may contribute significant amounts of toxic or
hazardous pollutants to navigable waters. The BMPs in today's regulations are directed,
among other things, at preventing or otherwise controlling leaks, spills and intentional
diversions of phenol, acetic acid, benzoic acid, carbon disulfide, p-cresol, formaldehyde,
formic acid, hydrogen sulfide, methyl mercaptan, and sodium hydroxide from spent pulping
liquor at mills with pulp production in Subparts B and E. See Chapter 5. EPA has
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2.0 Legal Authority
designated phenol as a toxic pollutant under CWA section 307(a)(l), see 40 C.F.R. § 401,15,
and has designated acetic acid, benzoic acid, carbon disulfide, p-cresol, formaldehyde, formic
acid, hydrogen sulfide, methyl mercaptan, and sodium hydroxide as hazardous substances
under CWA section 311, see 40 C.F.R. § 116.4. Turpentine, in turn, is ignitable, which is a
characteristic of section 311 hazardous substances under 40 CFR Part 302. Turpentine and
the wastes from which it is derived (foul condensates) also contain two listed section 311
hazardous substances-hydrogen sulfide and methyl mercaptan~and the priority pollutants
phenol and toluene. Soap has a very high BOD5 content and contains materials that exhibit
significant toxicity to fish (see Section 5.6 for further discussion).
The Administrator has determined that leaks, spills and intentional diversions of spent pulping
liquor containing these pollutants are associated with various chemical pulping processes
discussed in Chapter 6, infra. The Administrator has also determined, for the reasons set forth
in Chapter 5, that failure to prevent or control the leaks, spills and intentional diversions of
spent pulping liquor could cause significant amounts of phenol and the identified hazardous
substances to enter the Nation's waters. In addition to phenol and the § 311 hazardous
pollutants identified above, EPA has also identified a number of other toxic compounds hi
spent pulping liquors from bleached papergrade kraft and sulfite mills that can have
significant adverse effects on navigable waters. These toxic pollutants are identified in Table
5-9, infra. Chapter 5, infra, also discusses the effects of spent pulping liquor and soap on the
toxicity of mill effluent. EPA intends that the BMPs established hi this regulation will
control the toxic effects of these pollutants. As the U.S. Court of Appeals for the D.C.Circuit
observed after reviewing the goals of the Clean Water Act and its legislative history, "The
indications are abundant that EPA was intended to possess broad latitude in identifying and
regulating suspected toxics." NRDC v. EPA. 822 F.2d 104, 118 (D.C. Cir. 1987)(upholding
EPA regulation requiring information in permit applications regarding effluent characteristics);
see Statement of Sen. Muskie (Dec. 15, 1977), 95th Cong., 2d Sess., reprinted in A
Legislative History of the Clean Water Act of 1977, Vol. 3, at 453-54 (1978) (citing a spill of
mirex to illustrate need for § 304(e) authority, even though mirex is not designated as a §
307(a) toxic pollutant or a § 311 hazardous substance).
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2.0 Legal Authority
For authority to impose BMPs on direct discharges, EPA also relies on sections 402(a) and
501(a) of the Clean Water Act and 40 C.F.R. § 122.44(k) of EPA's regulations. Under
section 402(a)(l), the Administrator is authorized to issue a permit "upon condition that [the]
discharge will meet either all applicable requirements under sections 301, 302, 306, 307, 308,
and 403 of this Act, or prior to the taking of necessary implementing actions relating to all
such requirements, such conditions as the Administrator determines are necessary to carry out
the provisions of this Act." EPA's authority to establish permit conditions under this section
is very broad. See NRDC v. Costle. 568 F.2d 1369, 1380 (D.C. Cir. 1977). As applied in
this context, section 402(a)(l) authorizes EPA to establish controls on "any pollutant, or
combination of pollutants," for which EPA has not yet promulgated effluent limitations
guidelines or standards under sections 301 or 306 that would be applicable to the permittee in
question. With the exception of pH, total suspended solids (TSS) and biochemical oxygen
demand (BOD), EPA has not promulgated effluent limitations guidelines or standards
applicable to Subparts B and E for the pollutants associated with spent pulping liquor, soap,
or turpentine. See Tables 5-1 through 5-9. While EPA expects that the BMPs will result in
incidental removals of TSS and BOD, the BMPs are intended to prevent or control the
releases of the other pollutants identified in the tables cited. In addition, section 402(a)(2),
read in concert with section 501 (a), authorizes EPA to prescribe as wide a range of permit
conditions as the Agency deems appropriate in order to assure compliance with applicable
effluent limits. (Section 501 (a) authorizes the Administrator to carry out her functions
through regulation.) EPA has determined that mills without an adequate BMP program, such
as that codified in the BMP regulation, may experience undetected and uncontrolled leaks and
spills that could disrupt the efficiency of their treatment systems, thus resulting in exceedances
of the BAT limitations and NSPS promulgated for Subparts B and E. See, e.g.. Chapter 1.
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Moreover, EPA's regulations at 40 C.F.R. § 122.44(k) specifically require permit writers to
impose, when applicable, BMP permit conditions to control or abate the discharge of
pollutants in any case when "[njumeric effluent limitations are infeasible" or when "[t]he
practices are reasonably necessary to achieve effluent limitations and standards or to carry out
the purposes and intent of [the] CWA." 40 C.F.R. § 122.44(k)(2) & (3), EPA has
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2.0 Legal Authority
determined that it is infeasible to establish numeric effluent limitations for each pollutant
likely to be controlled by BMPs because leaks and spills in particular tend to be accidental,
unpredictable releases and EPA is unable to specify with any degree of certainty the quantities
of pollutants to be regulated. See NRDC v. Costle. 568 F.2d at 1380. Moreover, numerical
effluent limitations are best suited for operational discharges deemed to represent application
of best available (or demonstrated) technologies or implementation of numeric water quality
criteria; they are not as effective or efficient as BMPs to prevent leaks and spills. Finally, the
stated goal of the Clean Water Act is to eliminate the discharge of pollutants into the Nation's
waters. CWA section 101(a)(l). EPA has determined that BMPs, by preventing or '
controlling leaks, spills or intentional diversions, are an important step toward that goal,
particularly with respect to toxic and other pollutants. See CWA section 101(a)(l) & (3).
Therefore, EPA has determined that BMPs applicable to all pollutants in a mill's spent
pulping liquor, soap, and turpentine were necessary in order to carry out the purposes of the
Clean Water Act and hence are authorized under section 402(a)(l) and 40 CFR 122 44(k)
41
Although a requirement to establish and implement BMP plans of the type described in this
regulation could be imposed on a case-by-case basis under authority of section 402(a)(l) and
40 C.F.R. § 122.44(k), EPA has decided to promulgate the requirement on a categorical basis
for the class of facilities subject to Subparts B and E of Part 430 under section 304(e) and
under its broad authority conferred by section 501(a). Section 304(e) expressly authorizes
EPA to promulgate BMPs by regulation on a categorical basis. The spent pulping liquors,
soap, and turpentine covered by these BMPs contain numerous toxic pollutants and hazardous
substances subject to section 304(e), and hence may be controlled by regulation. In addition,
section 501 (a) authorizes the Administrator to prescribe such regulations as are necessary to
carry out her functions under the Act. EPA has determined that the BMP program of the type
specified in § 403.03 is necessary to ensure that each pulp and paper mill with pulp
production in Subparts B or E prevent or otherwise contain leaks and spills, and that they
control intentional diversions, of spent pulping liquors, soap and turpentine. While the BMP
regulation is intended to provide considerable flexibility to mills in designing their BMP
programs, EPA has also determined that the various BMPs specified in the regulation
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2.0 Legal Authority
represent the minimum elements of any effective BMP program. By codifying them into a
regulation of general applicability, EPA intends to promote expeditious implementation of a
minimum BMP program and to assure uniform and fair application of the baseline
requirements. EPA also believes that the regulation represents an appropriate and efficient
use of its technical expertise and resources that, when exercised at the national level, will
relieve state permit writers of the burden of implementing this aspect of the Clean Water Act
on a case-by-case basis. Thus, in order to ensure that minimal BMPs are in place for mills in
Subparts B and E and to promote efficient administration of the NPDES permit program,
EPA is promulgating BMPs for Subparts B and E by regulation.
EPA also relies on Section 308(a) as authority to require mills to develop and implement a
BMP Plan as prescribed in § 430.03, and to perform attendant monitoring and reporting
functions. Section 308(a) authorizes EPA, among other things, to require owners or operators
of point sources to establish and maintain records, make reports, install, use and maintain
monitoring equipment, sample effluent, and provide such other information as the
Administrator may require in order to carry out the objectives of the Act. Among other
things, EPA expects that the permitting authority will be able to use the information to
monitor the mills' compliance with the regulation's BMP implementation requirements. See
Sections 308(a)(2) and 402(a)(2). In addition, EPA expects that information provided by
mills under § 430.03 will assist EPA to evaluate the effectiveness of the BMP program it has
designed.
An important aspect of the BMP program codified by EPA is the flexibility it provides to
mills in deciding how to implement the various specified measures. This is consistent with.
the legislative history for Section 304(e), which EPA regards in this rulemaking as sensible
direction for the BMPs, even when imposed under other CWA authorities. Statement of Rep.
Roberts (Dec. 15, 1977), 95th Cong., 2d Sess., reprinted in A Legislative History of the Clean
Water Act of 1977, Vol. 3, at 341 (1978). It is also consistent with EPA's practice of not
prescribing specific technologies to achieve the performance objectives. By granting mills
considerable flexibility to choose the most cost-effective strategies for preventing and
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2.0 Legal Authority
otherwise controlling leaks, spills and intentional diversions of spent pulping liquors, soap,
and turpentine, EPA intends to maximize the opportunity for the individual point source to
consider various factors, e.g., the facility's age, type of pulp processes, the physical
configuration of the mill, and mill-specific constraints associated with recovery boilers and Ğ
evaporator and treatment systems, when implementing the BMP program.
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For authority to impose BMPs on indirect discharges, EPA relies on Sections 307(b) and (c)
of the Clean Water Act. 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. To determine whether pollutants associated with spent pulping liquors,
soap, and turpentine that are indirectly discharged by mills in Subparts B and E interfere with
POTW operations or pass through untreated, EPA reviewed data collected from 1988 through '
1992 at a POTW that receives effluent from a bleached papergrade kraft mill. See Chapter ;
9.3.1. Prior to 1990-91, the mill had virtually no facilities for control and collection of spent Jtjjk
pulping liquor leaks and spills. POTW discharge monitoring records show the fully treated
effluent exhibited consistent chronic toxicity to Daphnia from April 1988 until June 1991.
The data further show that the toxic effects of the POTWs effluent have been reduced since
implementation by the mill of effective spent pulping liquor management and spill prevention
control. See Chapters 5.4 and 9.3.1 and Tables 9-1, 9-2 and 9-3. These effluent toxicity
effects can be related to the wood extractive components that are measurable by COD and are
found in leaks and spills of spent kraft and sulfite pulping liquors that interfere with the
performance of biological treatment systems and allow toxic pollutants to pass through
inadequately treated. Indeed, evidence of such interference and pass through was found in
data from this mill and the POTW, which showed higher mass effluent loadings for COD,
TSS, and BOD before the mill implemented a BMP program. After the BMP program was
implemented, mass effluent loadings of these pollutants were reduced. Data for COD, in
particular, indicated that short-term interference of POTW operations previously observed at
higher COD levels was being mitigated. See Chapter 9.3.1. These data led EPA to conclude
that leaks and spills of spent pulping liquor interfered with POTW operations. Data from the
2-6
-------
2.0 Legal Authority
mill also show the effect of inadequate turpentine coiitrdl on POTW operations and caused
pass through of pollutants. See Chapter 9.3.1. Soap can also exhibit toxic effects on aquatic
life and biological treatment systems. See Chapter 5.6. EPA also considered a case study of
an incident in 1993 where a diversion of pulping liquor debilitated the mill's secondary
treatment system and killed fish in the receiving water. See Chapter 8 for a more detailed
discussion of this incident. Because direct discharging mills using these BMPs achieve very
high removals and because POTWs cannot achieve similar removals in the absence of BMPs
employed by the indirect discharger, EPA has determined that pollutants in spent pulping
liquor, soap and turpentine, in the absence of controls on leaks, spills and intentional
diversions, can cause disruption and interference and do pass through POTWs. For this
reason, EPA is including as part of its pretreatment standards the requirement that mills
implement BMPs in accordance with this regulation. EPA was unable to establish numeric
PSES for the pollutants of concern because the interference occurred only sporadically in
response to infrequent and unpredictable leaks and spills. However, EPA concluded that the
BMP Program codified in section 430.03 will minimize the interference and pass through
attributable to those pollutants and perhaps prevent it altogether.
2-7
-------
-------
3.0 WOOD COMPOSITION
The principal components of wood are cellulose, hemicelluloses, lignin, and extractives.
Cellulose is a linear polysaccharide consisting of \5-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 differs considerably from that 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 giucomannan (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. Lignin 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 as 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 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
3-1
-------
3.0 Wood Composition
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 specifically as
"priority pollutants" under the CWA by EPA.
3-2
-------
3.0 Wood Composition
table 3-1
Extractive Compounds Associated with Wood Pulping Operations
Extractive Compound
Kraft Pulping
Sulfite Pulping
Mechanical Pulping
Resin Acids
Abietic
Dehydroabietic
Isopimaric
Palustric
Pimaric
Sandaracopimaric
Neoabietic
/
S
S
/
/
S
/
/
^
S
S
S
S
S
S
S
^
/
/
/
^
Unsaturated Fatty Acids
Oleic
Linoleic
Linolenic
Palmitoleic
S
S
S
S
S
S
S
S
/
/
/
/
Diterpine Alcohols
Pirnarol
Isopimarol
Abienol
12E-abienol
13-epimanool
/
/
/
^
/
Juvabiones
Juvabione
Juvabiol
A! '-dehydrojuvabione
A l'-dehydrojuvabiol
S
S
S
S
/
/
/
t/'
Lignin Degradation Products
Eugenol
Isoeugenol
3,3 '-dimethoxy-4,4'-dihydroxystilbene
S
S
S
Sources: Kringstad and Lindstrom, 1984 (1); Springer, 1986 (2); Leach and Thakore, 1974 (3).
3-3
-------
-------
4.0
WOOD PULPING AND CHEMICAL RECOVERY SYSTEMS
4.1
Pulping Processes
In 1992, the United States pulp and paper industry produced nearly 66 million tons of wood
pulp by the following processes (6):
Process
Bleached Sulfate (Kraft)
Unbleached Sulfate
Semi-Chemical
Thermomechanical
Groundwood and Refiner
Total Sulfite
Dissolving and Special Alpha
Other
Total
Percent of Production
45.0
33.7
6.2 .
5.4
4.4
2.2
2.1 *
-1.0
100.0
Thousands of Tons
29,703
22,228
4,101
3,584
2,917
1,427
1,383
600
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.
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
i
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.
i
4.1.1.3 Thermomechanical Pulp
Thermomechanical pulp is produced by preheating wood chips with steam before refining (as
described hi Section 4.1.1.2). The heat acts to soften the lignin, which binds the wopd 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 blending with 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-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
4-2
-------
4.0 Wood Pulping and Chemical Recovery Systems
used; it ranges from 65 to 85%. Most sdmi-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
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):
Type of Mill
Kraft and Soda Mills
Dissolving Grade Kraft
Papergrade Kraft
Papergrade Soda
Total
Sulfite Mills
Dissolving Grade Sulfite
Papergrade Sulfite
Total
Number Ğf Mills
3
107
2
112
4
11
15
Ntunber of Mills Wjtfc
Bleaching
3
85
2
90
4
10
14
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
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 (TN^SO^} and
4-3
-------
4.0 Wood Pulping and Chemical Recovery Systems
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 55% 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 (i.e., soap)
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 brownstock (unbleached) pulp manufactured for production of bleached
pulp is characterized by two measures: (1) the Kappa Number1, and (2) the Permanganate
number or K Number. The K Number is a short test that can be performed within one hour
and produces results that are about one-third lower than corresponding Kappa Numbers for
softwood pulps and 30 percent lower for hardwood pulps. Kappa Numbers for conventionally
pulped, kraft softwood brownstock pulps are generally in the range of 28 to 34; those for
kraft brownstock hardwood pulps are in the range of 14 to 18. Kappa Numbers for
!TAPPI Test Methods T236CM-85 (Kappa number) and UM251 (K number) (Reference 34).
4-4
-------
4.0 Woojl Pulping and Chemical Recovery Systems
unbleached sulfite pulps are lower than for kraft pulps, 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 pulphig 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 to 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 direct contact evaporation design recovery boilers;
Further concentrating strong black liquor in concentrators to "heavy
black liquor," typically greater than 65% liquor solids;
Adding salt cake (Na2SO4) 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 most of the inorganic
chemicals are recovered in molten form as smelt. Some of the
inorganic chemicals are recovered as the catch in air emission control
systems on the recovery furnaces;
4-5
-------
4.0 Wood Pulping and Chemical Recovery Systems
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 lime
kiln to form lime (CaO) for reuse in the causticizing circuit.
Cited references should be consulted for more detail 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 (H2SO3) and bisulfite ion (HSO 3.) 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 to 2, while "bisulfite" pulping is
conducted under less acidic conditions in the range of pH 3 to 5 (8). !
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)
4-6
-------
4.0 Wood Pulping and Chemical Recovery Systems
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).
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.
4-7
-------
4.0 Wood Pulping and Chemical Recovery Systems
Table 4-1
Comparison of Kraft and Sulfite Pulping Processes
Process Characteristic
Cellulosic Raw Material
Principal Reaction in Digester
Composition of Cooking Liquor
Cooking Conditions
Chemical Recovery
Pulp Characteristics
Typical Paper Products
Kraft,lProeess
Almost any kind of wood, soft or
hard
Hydrolysis of lignins to alcohols
and acids; mercaptans are formed
12.5 % solution NaOH,
Na2S, and Na2CO3
2 to 5 hours at 340-350 °F and
100-135 psi
Most of process is devoted to
recovery of cooking chemicals,
with energy recovery from
burning organic matter dissolved
in liquor. Chemical losses are
replenished with salt cake,
Na2S04.
Brown color; difficult to bleach;
strong fibers; resistant to
mechanical refining
Strong brown bag and wrapping;
multiwall bags; gumming paper;
building paper; white papers from
bleached kraft; paperboard for
cartons, containers, and corrugated
board
Sulfite Process
Any hardwood and non-resinous
softwood; must be of good color
and free of certain hydroxy
Ephenolic compounds
Sulfonation and solubilization of
lignin with bisulfite; hydrolytic
splitting of cellulose-lignin
7 % by weight SO2, of which 4.5
% is present as sulfurous acid,
and 2.5 % Ca, Na, NH3 or
Mg(HSO3)2 ;
6 to!2 hours at 257-320
90-1 10 psi ;
and
SO2 relief gas recovered; Mg or
Na liquor recovered after wood
digestion and washing. Ammonia
can be recovered in some
ammonia-base pulping systems.
Dull white color; easily bleached;
fibers weaker than kraft fibers
Book paper, bread wrap, sanitary
tissue
Sources: EPA, 1982 (5); Green and Hough, 1992 (9); Ingraber, et al., 1985 (11).
4-8
-------
4.0 Wood Pulping and Chemical Recovery Systems
Figure 4*-l
Kraft Process
Simplified Schematic Diagram
CHIPS
1
Blow Tank
I
Washers
1 '
Weak Black
I
=====
White Liquor
=O PULP
Contaminated
Condertsate
\
Strong Black
I
White Liquor
Oarffier
Lime
Mud
Lime Mud
Washer
Weak Liquor
Storage
Grits
1
i
Slaker
Lime
Lime
Kiln
Water
t
Recovering
Furnace
Smelt
h
Dissolving
Tank
Drags
Source: Smook, 1989 (8)
4-9
-------
4.0 Wood Pulping and Chemical Recovery Systems
Figure 4-2
Kraft Pulping and Chemical Recovery
Simplified Schematic Diagram
Source: Green and Hough, 1992 (9)
4-10
-------
4.0 Wood Pulping and Chemical Recovery Systems
Figure 4-3
Ammonia Base Sulfite Pulping
Simplified Schematic Diagram
COMBUSTION CHAMBER
ABSORPTION TOWER
STORAGE r-ğ SCRUBBER
LOW PRESSURE ACCUM.
HIGH PRESSURE ACCUM.
BURNER GAS
COOKING ACID
SPENT LIQUOR
SULFITE PULP
Source: Libby, 1962 (10)
4-11
-------
O)
g
§
1
s
S-
s,
a
o
o
~=
two
f 2
,2* w
s .2
PW p
Ğ
s g
w §
a> d
en W
<5 M
il
;s o,
Ğ s
U.s
ON
o
o
00
4-12
-------
4.0 Wood Pulping and Chemical Recovery Systems
Figure 4-5
Sodium Base Sulfite Pulping
Simplified Schematic Diagram
WOOD CHIPS
WATER MĞ MAKEUP SULFUR MAKEUP SPENT LIQUOR
TOWCR
ACID f~
AC1O STORAGE
PL
P
LOW PRESSURE ACC.
ħ
[HICK PRESSURE ACC.I
L__^
COOKtNC ACID
L_
EVAPORATORS
H 5 SMELT SO^ FLUE CAS
AI
-------- 1
j - -
'I55OLVER j-Ğ-i
^
RELIEF r-^-j CARBONATION TOWER
OLOW CA3
BLOWTANK
] -
SPENT
LiQUOB
SVLFITIKC TOWER
COMOEKSATE
SULFITE PULP
Source: Libby, 1962 (10)
4-13
-------
4.0 Wood Pulping and Chemical Recovery Systems
Figure 4-6
Magnesium Base Sulfite Pulping
Simplified Schematic Diagram
WOOD
CHIPS MAGNESIA MAKEUP
i-
ğ i
GAS MqO -Ğ
1 ?
L *
1 -j ABSORPTION T
J
[STORAGE | p-fs^
,. 1 1 ..
[ LOW PRESSURE
HIGH PRESSURE
1
COOKING i
L_
i
, *
STEAM _{ DIGESTER
^
BLOW GAS _| BLOWTANB
WATER S
,
OWER ]-J
-RUB8ER(-J
i
ACCUM. ] ,
1 ..
ACCUM. |
>.CIO
h
h
Ul
-^-
-FUR
i
j
fT
L
i .
RELl
SPE
MAKEUP SPENT
.
EVAPORATORS
1 f
* L_
BOILER
FURNACE
}
L CYCLONE
| j
CAS MgO
EF
NT LIQUOR _
1
-vĞ
QU1
1
~\
1
p>p
^"-CONDENSATE
* STEAM
f
*
SULFITE PULP
Source: Libby, 1962 (10)
4-14
-------
4.0 Wood Pulping and Chemical Recovery Systems
Figure 4-7
Sulfite Recovery Systems Currently in Use
Magnesium Base
Ammonium Base
Incinerate
Evaporate .
Wet Combination
- Dispose
- Burn
- Pyrolyze
- Dry
Calcium Base Evaporation
and Burning
Recover by-products -
Lime Precipitate
Thermally Precipitate
Treat Biologically
Evaporate and Burn to
Magnesium .Oxide and SO,
Ion Exchange
Incinerate
Evaporate and Dry
Evaporate and Burn
Lignin Chemicals -
Yeast (protein)
Alcohol
Babcock & Wilcox, Lenzing. Piakt
Copeland Fluid Bed
- No Recovery
- Recovery SO2
- Recover NH3 and SO2
Ion Exchange
Base Exchange
Pyrolyze
Ammonium Base
Evaporation and
Burning
- Na
- Mg
-* Ca
Evaporate and Burn-
Incinerate
Evaporate and Burn Under
Oxidizing Conditions
Wet Combustion -ğ [Zimmerman
Electrolyze
Ion Exchange
Evaporate and Pyrolyze
Precipitate
Recover by-products
Treat biologically
with AI(OH)3 -j. |Sonoco~
Fluid Bed Copeland & Dorr-Oliver
SCA
Lignin Chemicals T* font Paper)
Yeast (Protein) ' '
Alcohol -ğ JQnt7
coo ^ nt.
Evaporate and Burn Under Reducing Conditio^i
Oxidize directly to sulfite
Separate sulfide
Leach and oxidize to sulfite
Strip as HzS with^
^ NaHCO3 -ğ [Rauma
CO2. NaHSO3
Organic acid
Acid exchange resin
Isolate sodium carbonate
Leach and centrifuge -* [ RAS |
Crystallize -ğ [Tampella Raurna ]
Soxirce: Ingruber, et al., 1985 (11)
4-15
-------
CO
&
o
8
s
a
a
c
a
P-
-a
I
cc
4
I
OJD
S
on
CO
O
1 s
"S Ğ
§ &D
U .S3
.
"= 1
s s
P
-------
4.0 Wood Pulping and Chemical Recovery Systems
! Figure 4>-9
Fluidized Bed System For Treatment of NSSC Waste Liquor
Simplified Schematic Diagram
TTcĞr\ l_l 1 t
FROM MILL
WEAK LIQUOR
STORAGE
ğ -10 x notion
r
!" TR7PLEF EFFECT ^~]
EVAPORATORS
-*- V J M J M
il i 1
v_ vL v
v 'J v- t. V *,
1
i ATMOSPHERE
CONCENTRATED!
LIQUOR STORAGE 1
ğSX SOUO3 I 1
1 . _J f^n
| x WEAK
I r^ ^LIQUOR
^ - II - _^_^ I ' /WET\
1 c, .M^.-rtrrv U*J~1 SCRUBBER
FLUIOIZEO n [ i
8FO rrrt ONF *- 1
REACTOR 1 J ^x. ^ -rn
\ / T ' WEAK
\ } Y - " LIQUOR
\ / __DUST STORAGE
\ / RETURN
/>nrr/^\ -ğ
/I B^0<^ *
f , atoFtr
'))\ \r/// ^
' 1 ' '* '' ^^
^~^ SOLID PRODUCT
'
-------
-------
5.0 COMPOSITION AND TOXICITY OF PULPING LIQUORS, SOAP, AND
TURPENTINE
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
Sodium (Na)
Sulfur (S)
Carbon (C)
Hydrogen (H)
Oxygen (O)
Potassium (K)
Chloride (Cl)
Inerts
Percent of Black Liquor Solids
19.2
4.8
35.2
3.6
35.2
1.0
0.1
0.2
Liquors that have greater heating values (up to 6,500 BTU/lb of liquor solids) will tend to
have a higher fraction of carbon, and less oxygen and sodium; the opposite is true of liquors
that have lower heating values (9).
The primary inorganic constituents in black liquor include:
Sodium Hydroxide (NaOH);
Sodium Sulfide
5-1
-------
5.0 Composition and Toxicity of Pulping Liquors
Sodium Carbonate
Sodium Sulfate
Sodium Thiosulfate (Na2S2O3); and
Sodium Chloride (NaCl).
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 bla.ck
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 hi 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
Alkali Lignin
Hydroxy Acids
Extractives
Acetic Acid
Formic Acid
Methanol
Sulfur (S)
Sodium (Na)
Percent of Black Liquor
30-45
25-35
3-5
5
3
1
3-5
17-20
i
Solids
o
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
5-2
-------
5.0 Composition and Toxicity of Pulping Liquors
sodium base sulfite pulping liquors (11). The ammonia base liquors have higher levels of
organic materials, as measured by BOD5, 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 hi 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 mmimum lethal concentrations of several compounds for certain species ofDaphnia
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
i
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 ha Table 5-8.
5-3
-------
5.0, Composition and Toxicity of Pulping Liquors
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; I
Upgrade No. 1 Mill evaporators; and ;
Improve soap recovery.
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 25% and 20%,
respectively. Of the eight recommendations to reduce effluent toxicity, the two with the
highest priority (arid 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). In another well documented case, a large
release of spent pulping liquor and contaminated condensate resulted in failure of the
wastewater treatment plant which, in turn, resulted in an NPDES permit exceedanceiand a.
moderate fish kill in the receiving river (32, 33).. Also, 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
-------
5.0 Composition and Toxicity of Pulping Liquors
combined industrial and municipal wastewater volume treated at the POTW. 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 toxicity effluent limitations. 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, at which time installation of most of the spent pulping liquor spill
prevention and control facilities was completed (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, coinciding with implementation of 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 sulfite red liquor at 882 jig/L, and in samples of hardwood and softwood kraft
black liquor at concentrations ranging from 1,200 micrograms per liter (/ig/L) to more than
50,000 ju,g/L, which exceeds the water quality criteria for phenol. See 45 Fed. Reg. 79318,
5-5
-------
5.0 Composition and Toxicity of Pulping Liquors
79338 (November 28, 1980) and supporting record. Based on this information, EPA has
determined that spills, leaks or intentional diversions of spent pulping liquor could contribute
significant amounts of phenol to U.S. waters. One softwood black liquor sample was
analyzed for zinc and found to contain 272 ^g/L. This level, though significant, is below
chronic and acute water quality standards (31). However, it has been EPA's longstanding
view that me appearance of a chemical on the section 307(a) toxic pollutant list indicates the
potentially toxic effects of its discharge. See 44 Fed. Reg. 32854, 32897 (June 7, 1979)
(promulgation of general 304(e) BMP regulations).
In addition, the following compounds found in spent pulping liquors and/or turpentine (and
the wastes from which it is derived) have been identified in EPA's list of hazardous
substances as codified at 40 C.F.R. §116.4: acetic acid, benzoic acid, carbon disulfide, p-
cresol, formaldehyde, formic acid, hydrogen sulfide, methyl mercaptan and sodium hydroxide.
EPA has examined the levels of these substances present in spent pulping liquor and, in the
case of hydrogen sulfide and methyl mercaptan, turpentine as they relate to potential releases
that are preventable through implementation of BMPs. "Average" preventable daily releases,
"maximum" releases (determined by adjusting the average daily release to account for
variability in release volumes at a mill prior to implementation of BMPs), and a "catastrophic"
spill (based on failure of a 300,000 gallon spent pulping liquor storage tank) were used as a
basis for quantifying the potential avoided releases of hazardous substances listed. The
analysis showed that potential releases of acetic acid and formic acid exceeded the "minimum
reportable quantity limit", as defined in 40 CFR 302.4, for both the maximum release and
catastrophic spill scenarios (35). Therefore, EPA has determined that spills, leaks, or
intentional diversions of spent pulping liquors and turpentine could contribute significant
amounts of hazardous substances to U. S. waters.
5.6 Toxic and Hazardous Pollutants Found in Turpentine and Soap
Turpentine and soap (tall oil), commonly called wood extractives, are normal components of
kraft mill spent liquor resulting from cooking the wood in a mixture of alkaline chemicals
5-6
-------
5.0 Composition and Toxicity of Pulping Liquors
under the normal manufacturing conditions. By weight, extractives comprise about 5% of
wood, but in terms of total COD are about 8% because of the high carbon content of many of
the compounds. Some components, such as methanol, are a result of chemical reactions that
degrade other constituents of the wood, particularly lignin. However, the majority of the
compounds come from the resinous material in softwood, commonly called pitch. For
practical purposes there are virtually no similar components in hardwoods.
Crude sulfate turpentine (generally known as simply "turpentine" in the kraft industry) is a
complex mixture of volatile compounds obtained from the pitch component of wood.
Turpentine leaves the kraft manufacturing process with the foul condensates formed when
steam from the cooking and black liquor evaporation is condensed.
Turpentine is relatively easy to separate from the digester blow condensate, both batch and
continuous, by decanting it and removing the top layer containing the insoluble turpentine.
Crude turpentine is often sold to reprocessors who purify it for sale to end users. It is also
frequently used as a fuel in the mill, effectively destroying all organic components, including
the priority pollutants.
Table 5-10 shows the major components of kraft foul condensates and their location in the
process. Two of the compounds listed as phenolics are phenol and toluene. Both compounds
are on the list of priority pollutants. Many other compounds found in crude turpentine are
extremely toxic and in addition, turpentine is ignitable.
There is no specific data available on the fraction of the contaminants in the foul condensates
that remain with the separated turpentine, but in view of the relatively simple flotation type
separation systems used, and the well known tendency for the separation to fail from time to
time due to carry-over of black liquor, it is apparent that most of the contaminants found in
the condensates were also found in the turpentine at least on occasion.
5-7
-------
5.0 Composition and Toxicity of Pulping Liquors
In addition to high BOD5 content1, soap and some of its constituents have been shown to be
highly toxic to fish, with minimum lethal concentration levels similar to listed hazardous
substances (see Tables 5-7 and 5-8). A 1947 NCASI technical bulletin (12) identified
sulfides, mercaptans, and soap components as the kraft pulping liquor constituents with
greatest potential for harming aquatic life if released in abnormally large quantities. :
Reported to be as high as 850,000 to 950,000 mg/L at one mill (26).
5-8
-------
5.0 Composition and Toxicity of Pulping Liquors
Table 5-1
Inorganic Content of Black Liquors
(Weight Percent, Dry Solids Basis)
Constituent
Sodium Carbonate
Sodium Sulfate
Active Alkali as Na2O
Sodium
Potassium
Sulfur
SulfatedAsh
Average
8.7
3.2
6.0
18.7
1.4
3.8
62.1
Minimum
6.6
0.9
3.9
17.2
0.4
2.6
57.3
Maximum
12.3
8.3
8.6
20.5
2.7
6.2
69.2
Source: Green and Hough, 1992 (9)
5-9
-------
,5.0 Composition and Toxicity of Pulping Liquors
Table 5-2
Components in Black Liquors
(Weight Percent, Dry Solids Basis)
Component
Lignin
Hemicellulose and
Sugars
Extractives
Saccharinic Acids
Acetic Acid*
Formic Acid*
Other Organic Acids
Methanol
Unknown Organic
Compounds
Inorganic Salts
Organically Combined
Sodium
Unknown Inorganic
Compounds.
Sulfur
Sodium
Total
Pine Liquor
28.9
1.14
6.69
3.52
4.48
5.5
19.0
18.6
10.1
2.08
100
JMne Liquor
30.7
0.11
2.53
2.08
2.7
2.22
29.5
18.5
10.3
1.35
100
Bine Liquor
31.1
1.3
5.7
18.8
5.2
3.1
5.8
20.3
8.7
100
l*ine Liquor
42
3.83
3.37
25.6
25.6
100
Spruce Liquor
41
f
3
1 28
i 5
3
: i
>
-,
; 3
' 16
! 100
*§ 311 hazardous substance
Source: Green and Hough, 1992 (9)
5-10
-------
5.0 Composition and Toxicity of Pulping Liquors
fable 5-3
Composition of Calcium Base and Magnesium Base
Sulfite Pulping Liquors
Characteristic
Pulp Yield (%)
Liquor Volume^1)
(m3/ODT)
pH
TOC (kg/ODT)
BOD(kg/ODT)
COD (kg/ODT)
Dissolved Organics
(kg/ODT)
Dissolved Inorganics
(kg/ODT)
UV Lignin (kg/ODT)
Total Sugars
(kg/ODT)
Reduced Sugars
(kg/ODT)
TEF(3)
Calcium Base
Mill 3
46
9.28
5.3
NT(2)
357
1,533
1,043
250
800
264
238
422
Magnesium Base \
mm i
54
6.56
3.4
NT(2)
169
807
651
173
469
94
32
316
M014B
45
5.61
3.3
NT(2)
275
1,144
913
79
533
165
180
NT(2)
Average
50
6.08
NT(2>
222
975
782
126
501
129
106
Notes:
(1) Estimated liquor volume a few minutes before "blow."
(2) NT - Not Tested.
(3) TEF - Toxicity Emission Factor
(100%/96hr LC50, %) x Liquor Volume (m3/ODT pulp)
(TEF approach in Table 5-3 was not developed by EPA.) '
Source: Ingruber, et al., 1985 (11)
5-11
-------
5.0 Composition and Toxicity of Pulping Liquors
Table 5-4
Composition of Ammonia Base and Sodium Base Sulfite Pulping Liquors
Characteristic
Pulp Yield
(%)
Liquor Vol(I)
(m3/ODT)
pH
TOC
(kg/ODT)(4)
BOD
(kg/ODT)
COD
(kg/ODT)
Dissolved
Organics
(kg/ODT)
Dissolved
Inorganics
(kg/ODT)
UV Lignin
(kg/ODT)
Total Sugars
(kg/ODT)
Reduced
Sugars
(kg/ODT)<4>
TEF^3^
Ammonia Ba$& (4 Mills)
Average ^
42.5
9.46
NT(2)
413
1,728
1,223
12.5
892
288
212
3,663
Minimum
41
9.11
1.5
NT(2)
319
1,553
1,167
7.0
822
210
160
3,313
Maximum
45
9.73
3.3
NT(2)
464
1,872
1,283
20
1,009
329
257
4,378
Sodium Base {12 Mills)
Average
62
7.10
.
697
235
938
595
226
410
137
74
714
Minimum
50
4.92
2.1
322
151
476
188
95
202
52
11
423
Maximum
80
10.67
4.8
1,652
371
1,757
1,178
: 348
853
; 278
218
1,208
Notes:
Source:
(1) Estimated liquor volume a few minutes before "blow."
(2) NT - Not Tested.
(3) TEF - Toxicity Emission Factor
(100%/96hr LC50, %) x Liquor Volume (m3/ODTpulp) \
(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.
Ingraber, et al., 1985(11) ;
5-12
-------
5.0 Composition and Toxicity of Pulping Liquors
Table 5-5
Composition of Typical Fresh NSSC Pulping Liquors
Chemical Compound
Sodium Sulfite
Sodium Hydroxide *
Sodium Sulfate
Sodium Thiosulfate
Sodium Sulfide
Total Sodium
Total Sulfur
Concentration
(grams/liter as chemical)
133
5.8
3.2
<0.1
< 0.1
53.0
35.1
*§ 311 hazardous substance
Source: Ingruber, et al., 1985 (11)
5-13
-------
5.0 Composition and Toxicity of Pulping Liquors
Table 5-6
Composition of Typical Spent NSSC Pulping Liquors
Characteristic
pH
Total Solids (%)
Volatile Solids (%)
(percent of Total Solids)
BOD5 (mg/1)
Acetate (mg/1)
Wood Sugars (mg/1)
(mostly pentoses)
Lignin (mg/1)
Oxygen Consumption (mg/1)
From KMnO4
From Ag-catalyzed dichromate-
Average
. 12
47.9
25,000
18,000
7,000
45,000
65,000
100,000
Minimum
6.5
8
43
16,000
12,000
5,000
25,000
55,000
83,000
Maximum
8.5
22
52
50,000
20,000
10,000
;85,000
142,000
235,000
Source: NCASI, Technical Bulletin 83
5-14
-------
5.0 Composition and Toxicity of Pulping Liquors
Minimum Lethal Concentrations to Daphnia and Fathead Minnows of
Components of Kraft Pulp Mill Wastewaters
Compound
Sodium Hydroxide *
Sodium Sulfide
Sodium Sulfate
Methyl Mercaptan *
Sodium Sulfite
Hydrogen Sulfide *
Sodium Carbonate
Sodium Sulfate
Crude Sulfate Soap
Sodium Salts of Fatty Acid Fraction of Sulfate Soap
Sodium Salts of Resin Acid Fraction of Sulfate Soap
Minimum Lethal Concentration
(parts per million)
Daphnia
100
10
5,000
1.0
300
1.0
300
5000
5.0-
10.0
1.0
3.0
Fathead Minnows
100
3.0
1,000
0.5
1.0
250
100
5.0
5.0
1.0
*§ 311 hazardous substance
Source: NCASI, 1947 (12)
5-15
-------
5.0 Composition and Toxicity of Pulping Liquors
Table 5-8
Critical Concentrations (Minimum Lethal Doses) to Fish of Components of
Sulfate (Kraft) Liquors
Component :_
Sodium Hydroxide *
Sodium Sulfide
Methyl Mercaptan *
Hydrogen Sulfide *
Formaldehyde *
Crude Sulfate Soap
Unsaponified Fraction of Sulfate Soap
Sodium Salts of Saponifiable Fraction of Sulfate Soap
Sodium Salts of Fatty Acids
Sodium Salts of Resin Acids
Sodium Oleates
Sodium Linoleate
Sodium Salts of Abietic Acid
Phytosterol
Sodium Tbiosulfate
Sodium Sulfate
Sodium Chloride
Sodium Hydrogen Sulfide *
Sodium Sulfide (as Sulfide)
'
-------
Table 5-9
Toxic Wastewater Pollutants and Hazardous Air Pollutants Found in Spent
Pulping Liquors
Analyte
Acetone
Benzoic acid
Benzyl alcohol
Benzanthrone
Bis(2-ethylhexyl)
phthalate
Butyl benzyl
phthalate
Carbon disulfide
p-Cresol
p-Cymene
p-Dioxane
Hexanoic acid
Methanol
Methyl ethyl ketone
Phenol
Alpha-Terpineol
1,3,5-Trithiane
Beryllium
Lead
Manganese
Regulatory
Status
HS
HAP,PP
PP
HAP,HS
HAP.HS
HAP
HAP
HAP
HAP
HAP, PP,
HS
PP
PP
Black Liquor Samples
MiB 3
SW
#g&
ND(500)
5,780
1,370
ND(500)
ND(IOO)
ND(IOO)
ND(IOO)
ND(IOO)
1,140
ND(IOO)
ND(IOO)
377,000
4,030
1,990
4,930
73,300
ND(0.06)C
ND (5.4)c
76.4C
Mill 5
HW
&£&
9,190
4,660
ND(IOO)
ND(500)
ND(IOO)
ND(IOO)
149
ND(IOO)
ND(IOO)
890
ND(IOO)
NA
2,410
1,230
322
ND(500)
NA
NA
NA
MiH 5
SW \
/Ğg/l* :
3,880
14,000
885
ND(500)
ND(IOO)
ND(IOO)
892
ND(IOOO)
ND(IOO)
ND(IOO)
ND(IOOO)
. NA
1,250
15,000
827
193,000
NA
NA
NA
Milt 6A
SW
;*g/La
2,500
ND(50)
ND(10)
75.1
ND(10)
ND(10)
19.0
ND(10)
ND(10)
ND(10)
ND(10)
535,000
442
523
ND(10)
ND(50)
NA
NA
NA
MIH6B
SW
P&t*
NA
3,480
ND(IOO)
ND(500)
351
370
NA
ND(IOO)
180
NA
ND(IOO)
366,000b
-------
Table 5-9 (Continued)
Analyte
Sodium
Zinc
Regulatory
Status
HS
PP
* 1"
'., * ,''."' ]*"
' " "' ', ' ' -"\f '
' ' ' ,' '''' t'%*
Black Liquor Samples
mm 3
sw
/Ч&
139,000°
14.9°
Mil! 5
HW
Ag/L
NA
NA"
Mill 5
sw
pg/L
NA
NA
MiH 6A
SW
vzfr?
NA
NA
MSH6B
sw ;
pg/t-
13,300,000
272 |
Bed
Uquor
Sample
Mm?
sw
V£fl>
NA
NA
HVV - Hardwood.
SW - Softwood.
HAP - Hazardous air pollutant
PP - §307a Priority pollutant.
HS - §311 Hazardous substance.
ND - Not detected (at reported detection limit).
NA - Not analyzed.
aConverted from units of jtg/kg to /xg/L.
An average of several grab samples is shown.
°Units are mg/kg (sample contained 6.6% solids).
5-18
-------
Table 5-10
- 7- ? V .4
Major Components Found in Kraft Condensate Prior to Separation of
Turpentine
Hydrogen
sulfide, ppm
Methyl
mercaptan, ppm
Dimethyl sulfide,
ppm
Dimethyl
disulfide, ppm
Methanol, ppm
Ethanol, ppm
Acetone
MEK, ppm
Teipenes, ppm
Phenolics, ppm
Guaiacol, ppm
Resin acids, ppm
Batch Digester
Vent Condensate
30-270
20-5,300 ~
15-7,400
5-4,100
1,800-12,000
90-3,200
8-420
27
0.1-5,500
12
Batch Digester
Plow
Condensafe
1-230
40-340
40-190
2-210
250-9,100
20-900
5-95
720-9,200
Continuous
Digester Flash-
Steam
Condensate
210
70
570-8,900
1,950-8,800
Evaporator
Combined
Condensate
1-90
1-30
1-15
1-50
180-700
1-190
1-15
1-3
60-1,100
1-10
25-230
Evaporator
Condenser
Condensate
1-240
1-410
1-15
1-50
180-1 ,200
1-130
1-16
2
450-2,500
3
Stripper Feed
5-660
5-720
10-1,000
10-150
140-10,000
20-1,100
1 15-500
20-25
800-13,000
1-82
Source: Blackwell et al (36).
5-19
-------
-------
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. In the
absence of adequate collection and recovery (or controlled rate of release to the wastewater
treatment plant), intentional diversions can have the same adverse impacts as a spill of similar
size. Unintentional losses result from fiber and liquor spills, equipment leaks, tank
overfillings, and process upsets.
9
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. 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
6-1
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6.0 Sources of Spent Pulping Liquor Losses
Losses from knotters and screens at mills without fiber and liquor
recovery systems for those sources. :
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 j
i
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 Pulping Liquor 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
6-2
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6.Q Sources of Spent Pulping Liquor Losses
directed to wastewater treatment systems. Despite these limitations, the information regarding
the causes of the spills is informative and useful for planning new and upgraded pulping
liquor spill, prevention, and control programs.
A summary of the pulping liquor spills is provided in Table 6-1. The 82 reported incidents
included 59 black liquor spills, 12 white liquor spills, 10 green liquor spills, and 1 red liquor
spill at a sulfite mill. Table 6-1 provides a breakdown of spills between those spilled to land
(soil) and those spilled to water (sewer system, basins, wastewater treatment plant, or
receiving waters). Those spills to water that reach receiving waters without being contained
or treated are further broken out on Table 6-1. ,
j
It can be seen that the largest portion of reported small spills (<1,000 gallons) do not reach
receiving waters, whereas more than half of the reported spills greater than 10,000 gallons did
reach receiving waters. Approximately 40% of those spills of unknown volume were reported
to have reached receiving waters. The two spills of greater than 50,000 gallons included a
96,000-gallon black liquor spill in Maine and a 90,000-gallon green liquor spill in Florida.
The ERNS reports do not include information on the effect of the spills on wastewater
treatment plants or the extent of pass-through (20).
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
6-3
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6.0 Sources of Spent Pulping Liquor Losses
included improper closure of valves and vehicular accidents inside and outside the pulp mills
(20).
6.4 Untreated Wastewater Loadings 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 BOD5 loading from decker filtrate and intermittent,
uncontrolled losses is attributable to black liquor (2). :
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 AOX and BOD5
have been attributed to poor brownstock washing. However, 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 BMP discussion or in 40 CFR 430.03,
since improved brownstock washing is a part of the model process technology trains
considered in the development of BAT, NSPS, PSES, and PSNS for bleached papergrade
kraft and soda mills.
Table 6-2 provides untreated wastewater loadings from a typical bleached kraft mill (2).
These data indicate that pulping and chemical recovery processes account for nearly 15
kilograms (kg) BOD5 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
BOD5 loading from pulping and chemical recoveiy operations originates hi foul condensates
and losses of spent pulping liquor.
6-4
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6.0 Sources of Spent Pulping Liquor Losses
NCASI estimates that the BOD5 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 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 lower limit 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 typical kraft mill is also reported at 5
kg/ADMT for pulping and chemical recovery operations (2).
6.5 Untreated Wastewater Loadings for Sulfite Mill
Table 6-3 presents approximate untreated wastewater loadings normalized to pulp production
for two sulfite mills. At both mills, most of the BOD5 wastewater loading is associated with
Ğ ....
pulping and chemical recovery operations. For the calcium-based sulfite pulp 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.
Based on data supplied in survey questionnaires, the overall BOD5 levels in untreated
wastewaters from ammonia-based mills and specialty mills are similar to those shown in
Table 6-3. By virtue of the use of similar processing steps and equipment, these mills should
exhibit comparable BOD5 and TSS loadings for the pulping, recovery and washing areas.
6-5
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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)
Volume Spilled
(gallons)
<100
100 to < 1,000
1,000 to < 5,000
5,000 to < 10,000
10,000 to < 50,000
> 50,000
Unknown Volume
Total
Number of Reported Spills j
Total
21
12
15
5
2
27
82
Media Affected
Laftd
18
7
9
1
1
11
47
Water
(All Types)*
-3
5
6
4
1
16
35
Receiving
Waters
3
! 5
5
:
[ 3
1
'. 11
I 28
Source: EPA ERNS, 1993 (20)
"Includes sewer system, WWTP, basins, and direct to receiving waters.
6-6
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6.0 Sources of Spent Pulping Liquor Losses
Table 6-
Typical Untreated Wastewater Loadings From a Typical Bleached Kraft
Mill
Process
Wood Yard
Pulping
Recovery
Bleaching
Paper Manufacturing
TOTAL
Flow
(ra3/AğMT (%))
0.7 ( 4.8)
21 (14.3) .
17 (11.9)
48 (33.3)
52 (35.7)
138.7 (100)
TSS
@Eg/AI>MT{%)>
3.1 ( 6.2)
4.9 (10.0)
11.1 (22.5)
4.9 (10.0)
25.3(51.3)
49.3 (100)
B01>5
(kg/ADMT (%ğ
0.8 ( 2.3)
9.4(26.3)
4.1 (11.4)
12.7 (35.4)
8.9 (24.6)
35.9 (100)
Source: Springer, 1986 (2)
6-7
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6.0 Sources of Spent Pulping Liquor Losses
Table 6-3
Examples of Untreated Wastewater Loadings for Two Sulfite Mills
Process
Mill E - Calcium
Acid Making, Pulping,
Washing, Bleaching
External Recovery
Wet Air Oxidation
Paper Machines
TOTAL
Mill F - Magnesium
Pulping and Recovery,
Washing, Bleach Plant
Paper Machines
TOTAL
Flow
(m.J/ADMT (%))
;
67 (47)
76 (53)
143 (100)
TSS
(kg/ADMT<%)>
32.9 (57)
2.5 (4)
22.2 (39)
57.6 (100)
34.1 (41)
48.1 (59)
82.2 (100)
BO%
(kg/ADMT (%))
69.1 (38) !
77.0 (42) ;
18.5 (10)
17.7 (10)
182.3 (100)
71.2 (80)
18.1 (20)
89.3 (100) '
Source: EPA Mill Visit Reports: Mills E and F; 1992
Pulp, Paper and Paperboard Effluent Limitations Guidelines
6-8
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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 by EPA 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 subject to the BMP regulation 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 papergrade kraft and soda and papergrade sulfite mills subject to the BMP
regulation promulgated at 40 CFR 430.03, 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;
7-1
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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 i
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
by NCASI in 1974 (21). NCASI Technical Bulletin No. 276 contains recommended
7-2
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7.0 Spent Pulping Liquor Management, Spill Prevention, and Control:
Current Industry Practice
approaches for spill containment for all aspects of pulp and paper mill operations, sewer
monitoring, and management programs.
7.1.1 Management Commitment
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-through
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 losses; others use COD analyses of
grab or daily composite samples. At one mill, operators use a one-day BOD5 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 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
7-3
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7.0 Spent Pulping Liquor Management, Spill Prevention, ;and Control:
Current Industry Practice
visited two of the oldest bleached kraft mills in the United States, both originally constructed
in the early 1900s. Each of these mills has two pulping lines. 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 ernphasis
i
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 effluent treatment systems to achieve
similar effluent quality from an equivalent mill with poor spill control. 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. Technical personnel at these mills believe that operator training and awareness is
the most significant feature of then- effective spill control programs.
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
necessary 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 waslu'ng
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;
7-4
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7.0 Spent Pulping Liquor Management, Spill Prevention, and Control:
Current Industry Practice
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 in critical
process areas (e.g., digesters, evaporators, recovery boilers, brownstock washers, knotters, and
screens) and to provide liquor collection sumps for each area. These mills 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 mill 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 of pulping liquor losses 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
7-5
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7.0 Spent Pulping Liquor Management, Spill Prevention, and Control:
Current Industry Practice
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 immediately.
Based on an evaluation of mills 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 and diverting stormwater "run-on" from entering liquor collection sumps, to
the extent practical. 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 BOD5. Soap is a material that is high in
organic content (850,000 to 950,000 mg/L of BOD5 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
7-6
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7.0 Spent Pulping Liquor Management, Spill Prevention, and Control:
Current Industry Practice
tanks through proper operation and design, and frequent visual inspections and secondary
containment where feasible. EPA site visits and the NCASI BMP survey have shown that
most mills provide secondary containment for turpentine storage tanks and have taken
measures to prevent turpentine and soap spills from reaching wastewater treatment systems.
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:
Energy value;
Cost of replacement chemicals, primarily equivalent saltcake;
Reduction in BOD5 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 papergrade kraft mill (27) is presented below.
The value of recovered chemicals is significant in cases where mills purchase saltcake.
However, for today's bleached papergrade 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
7-7 .
-------
7.0 Spent Pulping Liquor Management, Spill Prevention, and Control:
Current Industry Practice
liquor solids will also reduce the BOD5 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%.
Where a mill lacks sufficient evaporator capacity, the break-even cost will be higher because
the mill will need to allow for increasing the evaporator capacity. Conversely, there could be
substantial investment and operating cost savings hi 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 rand
green liquors at kraft mills will likely be cost-effective in many cases.
7-8
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7.0 Spent Pulping Liquor Management, Spill Prevention, and Control:
Current Industry Practice
7.2 Sulfite Mills
At the sulfite mills evaluated, spent pulping liquor management, spill prevention, and control
programs include many of the same features described above for kraft and soda mills. 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 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.
7-9
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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
Weak Liquor
Strong Liquor
Strong Waste or
Spill Tank
Fiber Salvage
Intermediate
Liquor
Wastewater
Diversion Basin
Mil! A
1760 ADMT/day
852,000 (25 - 84%)
852,000 (25 - 84%)
177,000 (50%)
837,000 (0%)
57,000 (20 - 35%)
MHIB
770 ABMT/day
1,500,000 (75%)
152,000 (90%)
345,000 (0%)
345,000 (0%)
5,000,000
Mill C
680 ADMT/rfay
686,000 (25 - 75%)
158,000 (60 - 70%)
1,500,000 (30 - 35%)
i
Source: EPA Project Files: Mill Visit Reports; Mills A, B, and C; 1992
Pulp, Paper and Paperboard Effluent Limitations Guidelines
7-10
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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
Accumulators
Fresh Acid Storage
Weak Liquor Storage
Strong Liquor Storage
Diversion Tank or Basin
MSUE
18ft ABMlYday
65,000 (80%)
95,500 (70%)
85,000 (50%)
88,000 (60%)
1,200,000 (40%)
MfflF :
21fl ADMT/day
50,000 (50%)
300,000 (65%)
1,650,000 (50%)
1,650,000 (50%)
Not specified
MiHG
. 140 ABMT/day
5,000,000
Source: EPA Project Files: Mill Visit Reports; Mills, E, F, and G; 1992
Pulp, Paper and Paperboard Effluent Limitations Guidelines
7-11
-------
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7-12
-------
8.0 BMP REGULATORY APPROACH, REQUIREMENTS, AND IMPLEMENTATION
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
implement Best Management Practices (BMPs) to prevent and control spent pulping liquor
losses, other than those losses associated with normal brownstock pulp washing, and to
prevent and control losses of turpentine and soap. Mills subject to the regulation are further
required to prepare and maintain a BMP Plan addressing elements noted later, and to review
and revise the plan as specified hi the regulation. For direct dischargers, this requirement will
be implemented through their NPDES permits. Existing direct dischargers are subject to the
compliance dates established in the regulation, while new sources must comply immediately
upon commencing discharge except where noted. As pretreatment standards, these BMP
requirements apply directly to indirect dischargers, subject to the compliance dates established
in the regulation.
In many respects, the BMP Plan will be similar to the Spill Prevention Countermeasure and
Control (SPCC) Plans for oil spill prevention and control (see 40 CFR 112.7). The primary
objective of the BMPs is to proactively prevent losses and spills of spent pulping liquors,
soap, and turpentine; a secondary objective is to reactiyely 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 then- mills.
The BMPs are as follows:
1. The mill must return diverted or spilled liquor to the process to the
maximum extent practicable as determined by the mill, recover such
materials outside the process, or discharge spilled or diverted material at
a rate that does not disrupt the receiving wastewater treatment system.
Based on EPA's review of effective BMPs at selected mills,
preventative maintenance practices, standard operating procedures and
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8.0 BMP Regulatory Approach, Requirements, and Implementation
engineering controls are essential elements to ensure the objectives of
the BMP regulation are met on a mill-by-mill basis. :
i
2. The mill must establish a program of regular visual inspections (e.g.
once per day) of process areas with equipment items in spent pulping
liquor, soap, and turpentine service, 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, of
leaking equipment that cannot be repaired during normal operations.
The mill must also identify conditions under which production will be
curtailed or halted to repair leaking equipment or to prevent spent
pulping liquor, soap, and turpentine leaks and spills. Under the repair
program, the mill must also establish a process for tracking repairs over
time to identify equipment that may need to be upgraded or replaced,
based on the frequency and severity of leaks, spills, or failures. Regular
visual (and auditory) inspections by knowledgeable operators pan
provide an effective early warning system to detect leaks, spills and to
learn about possible equipment malfunctions before they turn into more
significant problems.
3. The mill must operate continuous, automatic monitoring systems that the
mill determines are necessary to detect and control leaks, spills, and
intentional diversions of spent pulping liquor, soap, and turpentine.
These monitoring systems should be integrated with the mill process
control system and may include, e.g., high level monitors and alarms on
storage tanks; process area conductivity (or pH) monitors and alarms;
and process area sewer, process wastewater, and wastewater treatment
plant conductivity (or pH) monitors and alarms.
4. The mill must establish 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 in spent
pulping liquor, soap, and turpentine service. The refresher training must
be conducted at least annually and should include consideration of
improved BMPs as a result of experience gained in the previous year.
The framing must be documented, and records of training must be
maintained for three years. EPA believes that initial and refresher
training is necessary to ensure that operators, maintenance and;
supervisory personnel are familiar with the BMPs selected for '
implementation at the mill, and to ensure their effective implementation.
5. The mill must prepare a brief report that evaluates each spill of spent
pulping liquor, soap, or turpentine that is not contained at the immediate
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8.0 BMP Regulatory Approach, Requirements, and Implementation
process area and any intentional diversion of spent pulping liquor, soap,
or turpentine that is not contained at the immediate process area. The
report must 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
as necessary to prevent recurrence. Discussion of the reports must be
included as part of the annual refresher training.
6. The mill must establish 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 such review is to prevent leaks
and spills of spent pulping liquor, soap, and turpentine during the
planned modifications, and to ensure that construction and supervisory
personnel are aware of possible liquor diversions and of the requirement
to prevent leaks and spills of spent pulping liquors, soap, and turpentine
during construction.
7. The mill must install and maintain secondary containment (i.e.,
containment constructed of materials impervious to pulping liquors) for
spent pulping liquor bulk storage tanks equivalent to the volume of the
largest tank plus sufficient freeboard for precipitation. An annual tank
integrity testing program, if coupled with other containment or diversion
structures, may be substituted for secondary containment for spent
pulping liquor bulk storage tanks.
8. The mill must install and maintain secondary containment for turpentine
bulk storage tanks.
9. The mill must install and maintain curbing, diking or other means of
isolating soap and turpentine processing and loading areas from the
wastewater treatment facilities.
10. The mill must conduct wastewater monitoring to detect leaks and spills,
to track the performance and effectiveness of the BMPs, and to detect
trends in spent pulping liquor losses (see section 8.2.5 below).
Mill owners or operators are required to prepare and implement a BMP Plan for spent pulping
liquor, soap, and turpentine. EPA expects this plan to be proactive. The detailed provisions
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8.0 BMP Regulatory Approach, Requirements, and Implementation
i
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 are;as:
Management Commitment and Approval;
Employee Awareness and Training;
Preventive Maintenance;
Work Practices;
Surveillance and Repair Programs;
Engineering Analyses;
Engineering Controls and Containment;
Dedicated Monitoring and Alarm Systems; and
Monitoring of BMP Implementation.
As part of the BMP Plan development, each mill must conduct 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, soap, and
turpentine service ~ to determine the magnitude and routing of potential leaks, spills, and
intentional diversions of spent pulping liquors, soap, and turpentine during the following
periods of operation:
Startups and shutdowns;
Maintenance;
Production grade changes;
Storm or other weather events;
Power failures; and
Normal operations.
Maximum advantage for niinimizing the potential for spent pulping liquor losses can be taken
through thoughtful engineering analyses of affected process areas at each mill. i
Each mill must also conduct 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
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8.0 BMP Regulatory Approach, Requirements, and Implementation
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, must be provided for spent pulping liquor
bulk storage tanks. Alternatively, mill operators may substitute an annual tank integrity
testing program for hard secondary containment for spent pulping liquor bulk storage tanks,
provided that the annual tank integrity testing program is coupled with other containment or
diversion structures. Hard secondary containment must be provided for turpentine storage
\
tanks to ensure that spills or losses of turpentine do not adversely affect wastewater treatment
facilities. The flexibility to use a tank integrity testing program in lieu of secondary
containment for spent pulping liquor bulk storage tanks is provided because the number of
spill incidents relating to catastrophic tank failures has been relatively small, and at some
mills, the location of process equipment and storage tanks would make installation of full
secondary containment facilities difficult and costly in relation to the possible benefits.
The plan must include an analysis of the need for (and benefits of) continuous, automatic
monitoring systems to detect and control leaks and spills of spent pulping liquor, soap, and
turpentine. The monitoring plan and analysis should be conducted in conjunction with the
overall engineering analysis of containment, curbing, stream segregation, operating practices,
etc.
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.
The plan must include a description of the monitoring program implemented to track the
performance and effectiveness of the BMPs. The plan must include the statistically-derived
action levels required by the BMP regulation and must also specify the period of time that the
mill determines the action levels may be exceeded without triggering the responses specified
in the regulation.
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8.0 BMP Regulatory Approach, Requirements, and Implementation
The plan must include 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 are
determined by the publication date of the regulation. i
The BMP Plan must be reviewed by the senior technical manager at the mill. The BMP Plan
must be approved and signed 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 person signing the BMP Plan must
certify to the NPDES permitting or pretreatment control authority that the BMP Plan (or
amendments) has been prepared in accordance with the requirements of the regulation and in
accordance with good engineering practices. Since the mill manager is ultimately responsible
for approving the financial and human resources required to implement the plan, the plan
must be reviewed and signed by the mill manager. ;
Each mill subject to the BMP regulation must amend its BMP Plan whenever there is a
change in mill design, construction, operation, or maintenance that materially affects the
potential for leaks or spills of spent pulping liquor, turpentine, or soap from the immediate
process areas. Also, each mill subject to the regulation must complete a review and
evaluation of the BMP Plan five years after the first BMP Plan is prepared and, except when
amendment is required earlier due to mill changes, once every five years thereafter. As a
result of this review and evaluation, the mill must amend the BMP Plan within three months
of the review if the mill determines that any new or modified management practices and
engineered controls are necessary to reduce significantly the likelihood of spent pulping
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8.0 BMP Regulatory Approach, Requirements, and Implementation
liquor, soap, and turpentine leaks, spills, or intentional diversions from the immediate process
areas, including a schedule for implementation of such practices and controls.
Except as noted below for new sources, indirect discharging mills subject to .this section must
meet the deadlines below. Also, except for new sources, NPDES permits must require direct
discharging mills subject to this section to meet the deadlines below. If a deadline has passed
at the time the NPDES permit containing the BMP requirement is issued, the NPDES permit
must require immediate compliance with BMP requirements).
Upon commencing discharge, new sources subject to the regulation must implement all of the
BMPs specified in the regulation, prepare the BMP Plan, and certify to the permitting or
pretreatment authority that the BMP Plan has been prepared in accordance with the regulation,
except that the action levels must be established not later than 12 months after commencement
of discharge, based on six months of monitoring data obtained prior to that date.
The milestones and compliance dates for the BMP regulation are as follows:
Milestone Compliance Date
1. Prepare BMP Plans and certify to the permitting 12 months after date of
or pretreatment control authority that the BMP publication1
Plan has been prepared in accordance with 40
CFR 430.03, not later than
2. Implement all BMPs specified in 40 CFR 12 months after date of
430.03 (c) that do not require the construction publication
of containment or diversion instructions or the
installation of monitoring and alarm systems not
later than
3. Establish initial action levels required by 40 12 months after date of
CFR 430.03 (h) not later than publication
1 This is the date the regulation is published in the Federal Register.
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8.0 BMP Regulatory Approach, Requirements, and Implementation
Milestone Compliance Date
4. Commence operation of any new or upgraded 24 months after date of
continuous, automatic monitoring systems that publication
the mill determines to be necessary under 40
CFR 430.03(c)(3) (other than those associated j
with construction of containment or diversion
structures), not later than
5. Complete construction and commence operation 36 months after date of
of any spent pulping liquor, collection, publication
containment, diversion, or other facilities,
including any associated continuous monitoring
systems, necessary to fully implement BMPs !
specified in 40 CFR 430.03(c), not later than :
6. Establish revised action levels required by 40 45 months after 4ate of
CFR 430.03(h) as soon as possible after fully publication
implementing BMPs specified in 40 CFR '.
. 430.03(c), but not later than !
The time frames stated above were revised from compliance dates contained in the original
proposal. These new milestone dates were developed based upon comments received by EPA
and further consideration of the activities that must be completed for each milestone. The
completion of the BMP Plan involves a number of complex engineering analyses that will
require detailed examination of drawings, operating procedures, and maintenance recbrds.
The development of construction and monitoring approaches and schedules, required for the
plan, will involve both engineering and operating personnel examining "incident scenarios"
and alternative approaches. Supported by comments, EPA has determined that the BMP Plan
and certain BMP elements related to the existing systems can be completed in 12 months
(milestones 1, 2, and 3). Upon completion of the plan, an additional 12 months is allowed for
specification of monitoring equipment, procurement, delivery, and installation (milestone 4).
From the completion of the plan, 24 months are provided for those elements of the BMP
implementation that require construction (sumps, tanks, valves, piping, curbs, etc.). This time
span is provided to accommodate detailed engineering, design, specification, procurement,
scheduling of equipment shutdowns, construction mobilization and construction (milestone 5).
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8.0 BMP Regulatory Approach, Requirements, and Implementation
8.2 Implementation Guidance for Permit Writers and Pretreatment
Authorities
As described above, mill owners or operators will be required to develop and implement
BMPs using practices and procedures 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, soap and turpentine, EPA
anticipates that similar BMPs and controls may 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, soap and turpentine as part of the BMP
regulation codified at 40 CFR 430.03. 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. Permitting and pretreatment authorities have additional authority
under Section 402 of the CWA and the NPDES permit and pretreatment regulations at 40
CFR §403.5 and 122.44(k) 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 or equivalent
containment for soap and turpentine processing areas, are required by the BMP regulation.
Otherwise, the BMP 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
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8.0 BMP Regulatory Approach, Requirements, and Implementation
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, except that spent pulping liquor bulk storage
tanks require secondary containment or annual integrity testing.
8.2.3 Costs of BMP Compliance
As part of its effort to characterize the economic impact of the effluent limitations giiidelines
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 hi Section
9.0 are reasonable based on comparisons made with actual costs incurred by mill operators
who have implemented effective BMP programs and based on 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.
f
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 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
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8.0 BMP Regulatory Approach, Requirements, and Implementation
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 action levels as a measure of organic loading at the point
influent enters the wastewater treatment system or at another key location or locations in the
mill sewer system representative of the pollutant loading of spent pulping liquor, soap, and
turpentine to the wastewater treatment system. It also involves responding to exceedances of
these action levels with investigative and corrective actions, as appropriate. The BMP
regulation requires mill owners or operators to establish initial action levels based on at least
six months of monitoring data, and to revise these levels after the BMP Plan has been fully
implemented. Exceedances of the action levels will not constitute violations of NPDES
permits or pretreatment standards; however, failure to conduct the required BMP monitoring,
or failure to conduct investigative or corrective actions when the action levels are exceeded
(as described in the regulation), would constitute permit or pretreatment standard 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. COD can measure those
pollutants characteristic of spent pulping liquors that are somewhat toxic and refractory to
biological treatment. 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 miirwastewater monitoring characteristics could include
Total Organic Carbon (TOC), a simplified one-day BOD5 test, or another similar short-term
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8.0 BMP Regulatory Approach, Requirements, and Implementation
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
regulation provides flexibility for mill owners or operators to select any reasonable measure of
organic loading and/or spent pulping liquor losses. The BMP regulation requires daily
monitoring of the wastewater treatment system influent or, alternatively, daily monitoring at
other locations selected to isolate possible sources of spent pulping liquor, soap, or turpentine
from the other possible sources of organic-containing wastewaters that are tributary to the
wastewater treatment system. At each location, EPA expects that 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.
Mill owners or operators must establish statistically-derived upper and lower action 'levels
based on six months of monitoring data. EPA expects that these data will reflect normal mill
operations, with no data reflecting abnormal spills or losses of spent pulping liquor, soap or
turpentine. For example, running seven-day average 75th- and 90th-percentile values may be
I
derived and used as upper and lower control levels. When the lower action level is; exceeded,
mill operators must initiate appropriate investigative actions to determine the cause of such
occurrence (e.g., potential abnormal liquor losses). EPA anticipates that most mills:also
would initiate corrective actions at this point if appropriate. If the upper action level is
exceeded for the period of time specified in the BMP Plan, mill operators must initiate
corrective actions to bring the monitored mass loadings of COD, TOC, or another organic
measure to a level below the lower action level as soon as practicable. Subject to reissuance
dates of NPDES permits (for direct dischargers), existing dischargers must establish an initial
set of action levels within 12 months from date of publication of the regulation and a revised
set of action levels after the BMPs have been fully implemented, but not later than 45 months
from the date the regulation is published. New dischargers must establish action levels not
later than 12 months after commencement of discharge. '
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8.0 BMP Regulatory Approach, Requirements, and Implementation
The approach taken here is consistent with industry practice for the monitoring of many
process variables and process or equipment conditions. Process annunciator panels typically
supply an alert to operators, warning that they should examine a "developing" situation, such
as a tank filled to an abnormally high, though not critical, level or pressure at a pump
discharge lower than normal. That same annunciator would provide an alarm, usually in the
form of sound and a flashing light, when action is needed immediately, e.g., when damage or
an irretrievable process upset is imminent. The same philosophy which has led to this process
control approach can reasonably be applied to the monitoring of spent pulping liquor since
some loses, such as leaks at pump seals, will develop gradually and can be investigated and
repaired in response to a lower action level, while a major pipe joint failure should be dealt
with by immediate action if the loss rate threatens the downstream treatment capacity, as
indicated by the higher action level.
It may become necessary for the mill to establish interim action levels due to changes in mill
systems and operations not associated with the implementation of BMPs. These interim
action levels are a temporary measure to respond to significant changes in mill design,
operation, production, or maintenance that result in the existing action levels becoming
obsolete (ineffective in prompting timely investigation or action) prior to the establishment of
the revised (post-implementation) action levels. Examples might be the startup of a new fiber
line, long-term shutdown of a fiber line, or replacement/upgrade of a major equipment
component that impacts the wastewater discharge rate significantly.
Perhaps the clearest illustration of both the potential effectiveness of BMPs and the need for
initial and revised action levels is found hi the actual experience of a mill that carried out a
BMP program involving many of the elements required in the BMP regulation. This mill,
located in the southeastern U.S., implemented a spent pulping liquor spill prevention program
in 1990 and 1991. Figure 8-1 presents the 7-day running average COD data for a year prior
to the implementation of the spill prevention measures (1988) and the first year after
implementation (1992). The figure also includes example action levels shown at the 75th and
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8.0 BMP Regulatory Approach, Requirements, and Implementation
90th percentile levels of COD for each year. These data provide evidence of the effectiveness
of BMPs in several ways (19).
First, it is clear that the baseline COD has been substantially reduced, as illustrated by the fact
that the darker line (1992 data) is, at almost all times, lower than the 1988 data plot This is
also evident from the lower COD values represented by the 1992 example action leyels as
compared to the 1988 action levels shown on the figure. !
A second result of the implementation of the spill prevention program is the reductipn in the
magnitude of the of the COD excursions as illustrated by the heights of the peaks in the data
which for the most part correspond to major spent pulping liquor spills or intentional
diversions. The major spike in the 1992 data, occurring in June, was a result of a major
turpentine spill. Had the turpentine tanks and handling equipment been included in the spill
prevention program, as required by the new BMP regulation, this release may not have
occurred and the overall improvement illustrated by the comparison of the 1992 and 1988
data would have been even larger. This turpentine spill and its strong detrimental impact
upon the operation of the POTW is discussed later in Section 9.3.1 (19).
A review of an incident that occurred at kraft pulping mill in the Southeastern U.S. in July of
1993 provides further evidence of both the efficacy and cost-effectiveness of the
implementation of BMPs as called for in 40 CFR 430.03. This mill experienced a process
upset that resulted in a significant amount of foul condensate and spent pulping liquor being
sewered. When the color of the waste water treatment plant influent raised suspicions of
abnormally high chemical loadings, a number of "defensive measures" were taken by the
WWTP operators to maintain the health of the treatment process. Nonetheless, within two
days, the treatment plant outfall exhibited depleted oxygen levels and, shortly thereafter,
suspended solids in the effluent exceeded permit levels. Efforts to augment the plant bacteria
inventory did not reverse the trends and a fish kill resulted downstream of the plant outfall.
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8.0 BMP Regulatory Approach, Requirements, and Implementation
State officials ordered a shutdown of the mill while measures were taken to clean up and
restore the WWTP to effective and consistent operation.
Actions taken after the incident provide additional evidence that BMPs are effective hi
reducing the level of pollutants hi the mill effluent and in reducing the potential for major
incidents that can render the associated waster water treatment plant ineffective. First, a
detailed analysis of the incident showed that the absence of a feedback signal that would have
provided the operators with indication of a valve position (open/closed status) allowed the
upset condition to progress unchecked for some time. Had the failure of the valve to open in
response to a operator command been evident from a feedback indicator signal, the upset
could have been controlled early and the contaminated condensate could have been retained
and returned to the process, rather than sewered. This type of analysis is illustrative of the
incident review element of the BMP plan and should virtually eliminate a repeat of the
specific type of incident involved here. Additionally, the type of engineering analysis
required to develop a BMP plan for this particular mill may have uncovered the potential for
problems associated with the absence of a valve position indicator hi the control room for this
and other key valves and may have proactively avoided the upset, rather than the retrospective
approach noted above.
A second message from this particular case/incident is contained in the findings of a study of
the incident commissioned by the mill as part of the Consent Order that resulted from the
NPDES permit violation. This study was carried out by an engineering firm during the six
months immediately following the incident. The contractor examined the rate of BOD losses
associated with spills (by subtraction of "baseline" BOD levels in the effluent) before and
after the incident and found a 57% reduction in these losses. After examining the changes hi
the mill as a result of the incident, the contractor attributed the improved performance to:
Review of the incident with operating personnel;
Adjustments to brownstock washer operation;
Operational and design changes in the evaporator area;
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8.0 BMP Regulatory Approach, Requirements, and Implementation
Improved in-mill communications; and
Supplemental training for pulp mill and evaporator personnel.
It is important of note that the mill estimated the financial cost of the incident and resulting
NPDES permit exceedance to total $2,997,730, mostly attributable to a 7.5 day mill shutdown.
to restore the waste water treatment plant to effective operation. The company was also
required to spend an additional $500,000 on plant improvement measures aimed at pollution
prevention. In summary, the financial consequences of this single incident were
approximately equal to the full implementation cost of BMPs as required by 40 CFR 430.03
(32, 33).
8-16
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8-17
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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 folly implement BMPs for spent pulping liquor, soap, and turpentine at pulp and
paper mills.
9.1 Current Status of Spent Pulping Liquor Spill Prevention and Control
Systems 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 model 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 model 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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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:
Type of Mill
Kraft and Soda Mills
Sulfite Mills
Percent of Mills
4n Category 1
26%
20%
Percent of Mills in
Category 2
29%
33%
Percent of Mills in
Category 3
45%
47%
9.2
Equipment Costs for BMP Implementation at Pulp and Paper Mills
To develop the industry-wide costs, bleached papergrade kraft and soda and papergrade 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
wife 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, EPA determined the types of equipment necessary to
operate effective spill control systems. 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
survey, EPA determined that single line kraft mills will require up to five liquor collection
9-2
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9.0 Estimated Costs and Effluent Reduction Benefits
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 and containment
measures for soap and turpentine. 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:
Type of Mill
Single Line Mills
Moderately Complex Mills
Complex Mills
Kraft Mil
Investment Costs
$ 2,150,000
$ 3,250,000
$ 4,050,000
Sulfite Mill Investment Costs
$ 1,300,000
None
None
9-3
-------
9.0 Estimated Costs and Effluent Reduction Benefits
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:
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 years (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 bleached papergrade kraft mills are presented below. The first case
9-4 :
-------
9.0 Estimated Costs and Effluent Reduction Benefits
study also provides anecdotal evidence supporting the need for adequate containment of
turpentine as a part of an effective BMP program.
9.3.1 Southern U.S. Bleached Papergrade 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 less than 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.
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 hi 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.
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 promelas 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 Papergrade 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 hi 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).
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;
9-7
-------
9.0 Estimated Costs and Effluent Reduction Benefits
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 (less than 2% liquor 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
9-8
-------
9.0 Estimated Costs and Effluent Reduction Benefits
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, soap, and turpentine and
effective spill prevention and control can result hi 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, soap,
and turpentine 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.
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;
9-9
-------
9.0 Estimated Costs and Effluent Reduction Benefits
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 BOD5 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 BOD^ 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 reduction in untreated wastewaiter
BOD5 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.
9-10
-------
I
9.0 Estimated Costs and Effluent Reduction Benefits
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 hi the United
States have essentially complete spenit 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.
t
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%. [This is achieved by strategically
locating sumps, curbs and other diversion and collection systems so that
the spent liquor is recovered prior to (mixing with wastewaters or
already diluted spent liquor. Some mills collect and recover spent
liquor at lower liquor solids concentrations because of effluent color
considerations. Evaporator hydraulic i capacity is likely to be a limiting
factor that either will prevent many mills from recovering spent pulping
liquor at low liquor solids concentrations or require upgrades to
evaporators and/or appurtenant equipment to meet local requirements
(e.g., color limits).
Two case studies show that for mills jwith 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 coujd occur at mills where effective
spent pulping liquor management and spill control systems can be
installed instead of effluent color treatment systems or upgraded
biological treatment systems. i
I -
Additional benefits associated with effective spent pulping liquor
management that cannot be quantified include: a cleaner internal mill
environment for mill staff, and a cleaner receiving water environment
resulting from reduced effluent discharges, reduced secondary
environmental impacts achieved through the use of recovered chemicals,
and reduced risk of effluent limitation exceedances.
9-11
-------
9.0 Estimated Costs and Effluent Reduction Benefits
I
Table 9-1
BMP Implementation Status for Spent Pulping Liquor Control Systems at
Bleached Kraft and Soda Mills, and Sulfite Mills
Pulping Process
Bleached Kraft and Soda
Dissolving Kraft
Total
Papergrade Sulfite
Dissolving Sulfite
Total
^ , , , ' '
BMP Implementation Status
Number of Mills
in Category 1
(10 % costs) ^
22
1
23
3
0
3
Number of Mills in
Category 2
(up to 60 % costs)
25
0
25
3
2
5
Number of Mills
in Category 3
(np to 90 % co;sts)
37
2
39
5
2
7;
Sources: EPA Mill Visit Reports
NCASI, 1994 (23)
AF&PA, 1995 (24)
9-12
-------
9.0 Estimated Costs and Effluent Reduction Benefits
Table 9-2
BMP Investment Cost Estimates for Bleached Papergrade Kraft
and Soda Mills
B3PA Model BMP Technology
Liquor Collection Sumps
Liquor Storage Capacity (one
500,000-gallon tank)
Fiber Reclaim Tank(s)
Process Area Curbing and Diking
Turpentine and Soap Containment
Sewer Conductivity Monitoring
and Storage Tank Alarms
Initial BMP Plan Preparation and
Initial Operator Training
Total
Mill Complexity
Single Lane
$750,000
(up to 5 sumps)
600,000
150,000
(one tank)
200,000
150,000
150,000
150,000
$2,150,000
Moderately
Complex
$1,350,000
(up to 9 sumps)
600,000
300,000
(two tanks)
300,000
250,000
250,000
200,000
$3,250,000
Complex; :
$1,800,000
(up to 12 sumps)
600,000
300,000
(two tanks)
400,000
350,000
350,000
250,000
$4,050,000
Note: Derived from EPA Mill Site Visit Reports, EPA project files and Reference 23.
9-13
-------
9.0 Estimated Costs and Effluent Reduction Benefits
Table 9-3
BMP Investment Cost Estimates for Papergrade Sulfite Mills
EPA Model BMP Tecimology
Liquor Collection Sumps
Liquor Storage Capacity
(one 200,000-gallon tank)
Fiber Reclaim Tank
Process Area Curbing and Diking
Sewer Conductivity Monitoring and Storage Tank Alarms
Initial BMP Plan Preparation and Initial Operator Training
Total
Single JUtoe '
$450,000
(up to 3 sumps)
300,000
150,000 !
150,000 !
100,000
150,000 ;
$1,300,000
Note:
All sulfite mills have a single fiber line.
Derived from EPA Mill Visit Reports, EPA project files, and Reference 23.
9-14
-------
:: 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. Bleached Papergrade Kraft Mill Discharging to
POTW
POTW Effluent Characteristic
1988 Effluent
Quality
1992 Effluent
Quality
Percent Change ;
Flow (m3/ADMT)
95th Percentile
Median
Mean
Standard Deviation
Coefficient of Variation
154
120
117
24.2
0.21
140
127
121
17.9
0.15
+ 5.8
+ 3.4
-29
COD (kg/ADMT)
95th Percentile
Median
Mean
Standard Deviation
Coefficient of Variation
54.7
37.3
37.7
10.8
0.29
41.1
26.9
27.6
8.52
0.31
-28
-27
+ 6.8
TSS (kg/ADMT)
95th Percentile
Median
Mean
Standard Deviation
Coefficient of Variation
10.4
5.11
5.61
2.93
0.52
5.08
2.15
2.41
1.30
0.54
-58
-57
+ 3.8
BOD5 (kg/ADMT)
95th Percentile
Median
Mean
Standard Deviation
Coefficient of Variation
4.23
1.90
2.09
1.14
0.55
3.65
1.49
1.73
1.04
0.60
-23
- 17
+ 9.0
Source: EPA, 1993 (19)
9-15
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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 Characteristic
Flow (m3/adt)
BOD (kg/adt)
TSS (kg/adt)
Dissolved Solids (kg/adt)
Sodium (kg Na-^SC^/adt)
Toxic Contribution (TU m3/adt)
March 1982
135
40
8.6
200
146
1,060
Jwly 1985
106
29
5.3
145
108
335
Percent Reduction
21 %
27%
38%
27%
26%
68%
Note: TU - Toxic units calculated as the reciprocal of the LC50 using static bioassays multiplied by
100. Toxic units were converted to toxic contribution in m3/admt 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).
i
Sources: Scroggins, 1986 (29)
Sikes and Almost, 1986 (30)
9-16
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10.0 REFERENCES
1. Kringstad, K.P. and K. Lindstrom. Spent Liquors from Pulp Bleaching.
Environmental Science and Technology, 18(8), 236A, 1984.
2. Springer, A.M. 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.G. 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.
10-1
-------
10.0; References
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.
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, I.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 RJ. 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: City of Port St. Joe, Florida (1988-1992); St.
Joe Forest Products Company (1988-1992).
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. NCASI. 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.
10-2
-------
10.0 References
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.
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 10, 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.
31. Summary Report for Pulp and Paper Mills Sampling Program, EPA Contracts
68-CO-0032 and 68-C5-0013, June 1996.
32. Incident Report for Inland-Rome NPDES Permit Exceedances, Filed with
Georgia Department of Natural Resources, July 1993.
33. Pulp Mill and Evaporator Area Process Review, Prepared for Inland Container
Corporation by Rust Engineering, December 1993.
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, 10.0 References
34. TAPPI Test Methods, 1996-1997, TAPPI Process, Atlanta, Georgia, ISBN 0-
89852-334-6, 1996. '
35. Memorandum to Gary Amendola, from Dan Eisemann, Eastern Research
Group; Subject: Estimated Mass of Hazardous Substances Released in a Black
Liquor Spill Event; July 28, 1997.
36. Blackwell, B.R., W.B. MacKay, F.E. Murray and W.K. Oldham. 1979.
Review of kraft foul condensates - source quantities, chemical composition, and
environmental effects. TAPPI Vol. 62 No. 10, October 1979.
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ATTACHMENT A
BEST MANAGEMENT PRACTICES REGULATION
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§430.03 Best Management Practices for spent pulping liquor, soap, and turpentine
management, spill prevention, and control
(a) Applicability. This section applies to direct and indirect discharging pulp, paper,
and paperboard mills with pulp production in Subparts B (Bleached Papergrade Kraft and
Soda) and E (Papergrade Sulfite).
(b) Specialized definitions. (1) Action Level: A daily pollutant loading that when
exceeded triggers investigative or corrective action. Mills determine action levels by a
statistical analysis of six months of daily measurements collected at the mill. For example,
the lower action level may be the 75th percentile of the running seven-day averages (that
value exceeded by 25 percent of the running seven-day averages) and the upper action level
may be the 90th percentile of the running seven-day averages (that value exceeded by 10
percent of the running seven-day averages).
(2) Equipment Items in Spent Pulping Liquor, Soap, and Turpentine 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, soap, or turpentine. Sometimes referred to as
"equipment items." -
(3) Immediate Process Area: The location at the mill where pulping, screening,
knotting, pulp washing, pulping liquor concentration, pulping liquor 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.
(4) Intentional Diversion: The planned removal of spent pulping liquor, soap, or
turpentine from equipment items in spent pulping liquor, soap, or turpentine service by the
mill for any purpose including, but not limited to, maintenance, grade changes, or process
shutdowns.
(5) Mill: The owner or operator of a direct or indirect discharging pulp, paper, or
paperboard manufacturing facility subject to this section.
(6) Senior Technical Manager. The person designated by the mill manager to review
the BMP Plan. The senior technical manager shall be the chief engineer at the mill, the
manager of pulping and chemical recovery operations, or other such responsible person
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designated by the mill manager who has knowledge of and responsibility for pulping and
chemical recovery operations.
(7) Soap'. The product of reaction between the alkali in kraft pulping liquor and fatty
acid portions of the wood, which precipitate out when water is evaporated from the spent
pulping liquor.
(8) Spent Pulping Liquor: For kraft and soda mills "spent pulping liquor" means
black liquor that is used, generated, stored, or processed at any point in the pulping and
chemical recovery processes. For sulfite mills "spent pulping liquor" means 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-, or
sodium-based sulfite liquors).
(9) Turpentine: A mixture of terpenes, principally pinene, obtained by the steam
distillation of pine gum recovered from the condensation of digester relief gases from the
cooking of softwoods by the kraft pulping process. Sometimes referred to as sulfate
turpentine.
(c) Requirement to implement Best Management Practices. Each mill subject to this
section must implement the Best Management Practices (BMPs) specified hi paragraphs (1)
through (10) of this section. The primary objective of the BMPs is to prevent leaks- and spills
of spent pulping liquors, soap, and turpentine. The secondary objective is to contain, collect,
and recover at the immediate process area, or otherwise control, those leaks, spills, and
intentional diversions of spent pulping liquor, soap, and turpentine that do occur. BMPs must
be developed according to best engineering practices and must be implemented in a manner
that takes into account the specific circumstances at each mill. The BMPs are as follows:
(1) The mill must return spilled or diverted spent pulping liquors, soap, and turpentine
to the process to the maximum extent practicable as determined by the mill, recover such
materials outside the process, or discharge spilled or diverted material at a rate that does not
disrupt the receiving wastewater treatment system.
(2) The mill must establish a program to identify and repair leaking equipment items.
This program must include:
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(i) Regular visual inspections (e.g., once per day) of process areas with
equipment items in spent pulping liquor, soap, and turpentine service;
(ii) 'Immediate repairs of leaking equipment items, when possible. Leaking
equipment items that cannot be repaired during normal operations must be identified,
temporary means for mitigating the leaks must be provided, and the leaking equipment items
repaired during the next maintenance outage;
(iii) Identification of conditions under which production will be curtailed or
halted to repair leaking equipment items or to prevent pulping liquor, soap, and turpentine
leaks and spills; and
(iv) A means for tracking repairs over time to identify those equipment items
where upgrade or replacement may be warranted based on frequency and severity of leaks,
spills, or failures.
(3) The mill must operate continuous, automatic monitoring systems that the mill
determines are necessary to detect and control leaks, spills, and intentional diversions of spent
pulping liquor, soap, and turpentine. These monitoring systems should be integrated with the
mill process control system and may include, e.g., high level monitors and alarms on storage
tanks; process area conductivity (or pH) monitors and alarms; and process area sewer, process
wastewater, and wastewater treatment plant conductivity (or pH) monitors and alarms.
(4) The mill must establish 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
in spent pulping liquor, soap, and turpentine service. The refresher training must be
conducted at least annually and the training program must be documented.
(5) The mill must prepare a brief report that evaluates each spill of spent pulping
liquor, soap, or turpentine that is not contained at the immediate process area and any
intentional diversion of spent pulping liquor, soap, or turpentine that is not contained at the
immediate process area. The report must 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
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equipment and operating and maintenance practices as necessary to prevent recurrence.
Discussion of the reports must be included as part of the annual refresher training. \
i
(6) The mill must establish a program to review any planned modifications to the
pulping and chemical recovery facilities and any construction activities in the pulping and
i
chemical recovery areas before these activities commence. The purpose of such review is to
prevent leaks and spills of spent pulping liquor, soap, and turpentine during the planned
modifications, and to ensure that construction and supervisory personnel are aware of possible
liquor diversions and of the requirement to prevent leaks and spills of spent pulping liquors,
soap, and turpentine during construction.
(7) The mill must install and maintain secondary containment (i.e., containment
constructed of materials impervious to pulping liquors) for spent pulping liquor bulk storage
tanks equivalent to the volume of the largest tank plus sufficient freeboard for precipitation.
An annual tank integrity testing program, if coupled with other containment or diversion
structures, may be substituted for secondary containment for spent pulping liquor bulk storage
tanks.
f '
(8) The mill must install and maintain secondary containment for turpentine bulk
storage tanks.
(9) The mill must install and maintain curbing, diking or other means of isolating
soap and turpentine processing and loading areas from the wastewater treatment facilities.
(10) The mill must conduct wastewater monitoring to detect leaks and spills, to track
the effectiveness of the BMPs, and to detect trends in spent pulping liquor losses. Such
monitoring must be performed in accordance with paragraph (i) of this section.
(d) Requirement to develop a BMP Plan. (1) Each mill subject to this section
must prepare and implement a BMP Plan. The BMP Plan must be based on a detailed
engineering review as described in paragraphs (d)(2) and (3) of this section. The BMP Plan
i
must specify the procedures and the practices required for each mill to meet the requirements
of paragraph (c) of this section, the construction the mill determines is necessary to meet
those requirements including a schedule for such construction, and the monitoring program
i
(including the statistically derived action levels) that will be used to meet the requirements of
paragraph (i) of this section. The BMP Plan also must specify the period of time that the mill
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determines the action levels established under paragraph (h) of this section may be exceeded
\
without triggering the responses specified in paragraph (i) of this section.
(2) Each mill subject to this section must conduct 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, soap, and
turpentine service for the purpose of determining the magnitude and routing of potential
leaks, spills, and intentional diversions of spent pulping liquors, soap, and turpentine during
the following periods of operation:
(i) Process start-ups and shut downs;
(ii) Maintenance;
(iii) Production grade changes;
(iv) Storm or other weather events;
(v) Power failures; and
(vi) Normal operations.
(3) As part of the engineering review, the mill must determine whether existing spent
pulping liquor containment facilities are of adequate capacity for collection and storage of
anticipated intentional liquor diversions with sufficient contingency for collection and
containment of spills. The engineering review must also consider:
(i) The need for continuous, automatic monitoring systems to detect and control leaks
and spills of spent pulping liquor, soap, and turpentine;
(ii) 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, soap, and turpentine;
(iii) The potential for contamination of storm water from the immediate process areas;
and
(iv) The extent to which segregation and/or collection and treatment of contaminated
storm water from the immediate process areas is appropriate.
(e) Amendment of BMP Plan. (1) Each mill subject to this section must amend its
BMP Plan whenever there is a change in mill design, construction, operation, or maintenance
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that materially affects the potential for leaks or spills of spent pulping liquor, turpentine, or
soap from the immediate process areas.
(2) Each mill subject to this section must complete a review and evaluation of the
BMP Plan five years after the first BMP Plan is prepared and, except as provided in,
paragraph (e)(l) of this section, once every five years thereafter. As a result of this review
and evaluation, the mill must amend the BMP Plan within three months of the review if the
mill determines that any new or modified management practices and engineered controls are
necessary to reduce significantly the likelihood of spent pulping liquor, soap, and turpentine
leaks, spills, or intentional diversions from the immediate process areas, including a schedule
for implementation of such practices and controls: :
(f) Review and certification of BMP Plan. The BMP Plan, and any amendments
thereto, must be reviewed by the senior technical manager at the mill and approved and
signed by the mill manager. Any person signing the BMP Plan or its amendments must
certify to the permitting or pretreatment control authority under penalty of law that the BMP
Plan (or its amendments) has been prepared in accordance with good engineering practices
and in accordance with this regulation. The mill is not required to obtain approval from the
permitting or pretreatment control authority of the BMP Plan or any amendments thereto.
(g) Record keeping requirements. (1) Each mill subject to this section must maintain
on its premises a complete copy of the current BMP Plan and the records specified in
paragraph (2) of this section and must make such BMP Plan and records available to the
permitting or pretreatment control authority and the Regional Administrator or his or her
designee for review upon request.
(2) The mill must maintain the following records for three years from the date they
are created:
(i) Records tracking the repairs performed in accordance with the repair
program described in paragraph (c)(2) of this section;
(ii) Records of initial and refresher training conducted in accordance with
paragraph (c)(4) of this section;
(iii) Reports prepared in accordance with paragraph (c)(5) of this section; and
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(iv) Records of monitoring required by paragraphs (c)(10) and (i) of this
section.
(h) Establishment of wastewater treatment system influent action levels. (1) Each
mill subject to this section must conduct a monitoring program, described in paragraph (2) of
this section, for the purpose of defining wastewater treatment system influent characteristics
(or action levels), described in paragraph (3) of this section, that will trigger requirements to
initiate investigations on BMP effectiveness and to take corrective action.
(2) Each mill subject to this section must employ the following procedures in order to
develop the action levels required by paragraph (h) of this section:
(i) Monitoring parameters. The mill must collect 24-hour composite samples
and analyze the samples for a measure of organic content (e.g., Chemical Oxygen Demand
(COD) or Total Organic Carbon (TOC)). Alternatively, the mill may use a measure related to
spent pulping liquor losses measured continuously and averaged over 24 hours (e.g., specific
conductivity or color).
(ii) Monitoring locations. For direct dischargers, monitoring must be
conducted at the point influent enters the wastewater treatment system. For indirect
dischargers monitoring must be conducted at the point of discharge to the POTW. For the
purposes of this requirement, the mill may select alternate monitoring point(s) in order to
isolate possible sources of spent pulping liquor, soap, or turpentine from other possible
sources of organic wastewaters that are tributary to the wastewater treatment facilities (e.g.,
bleach plants, paper machines and secondary fiber operations).
(3) By the date prescribed in paragraph (j)(l)(iii) of this section, each existing
discharger subject to this section must complete an initial six-month monitoring program using
the procedures specified in paragraph (h)(2) of this section and must establish initial action
levels based on the results of that program. A wastewater treatment influent action level is a
statistically determined pollutant loading determined by a statistical analysis of six months of
daily measurements. The action levels must consist of a lower action level, which if exceeded
will trigger the investigation requirements described in paragraph (i) of this section, and an
upper action level, which if exceeded will trigger the corrective action requirements described
in paragraph (i) of this section.
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(4) By the date prescribed in paragraph O')(!)(vi) of this section, each existing
discharger must complete a second six-month monitoring program using the procedures
specified in paragraph (h)(2) of this section and must establish revised action levels based on
the results of that program. The initial action levels shall remain in effect until replaced by
revised action levels.
(5) By the date prescribed in paragraph (j)(2) of this section, each new source subject
to this section must complete a six-month monitoring program using the procedures specified
in paragraph (h)(2) of this section and must develop a lower action level and an upper action
level based on the results of that program.
(6) Action levels developed under this paragraph must be revised using six months of
monitoring data after any change in mill design, construction, operation, or maintenance that
materially affects me potential for leaks or spills of spent pulping liquor, soap, or turpentine
from the immediate process areas.
(i) Monitoring, corrective action, and reporting requirements. (1) Each mill subject
to this section must conduct daily monitoring of the influent to the wastewater treatment
system in accordance with the procedures described in paragraph (h)(2) of this section for the
purpose of detecting leaks and spills, tracking the effectiveness of the BMPs, and detecting
trends in spent pulping liquor losses.
(2) Whenever monitoring results exceed the lower action level for the period of time
specified in the BMP Plan, the mill must conduct an investigation to determine the cause of
such exceedance. Whenever monitoring results exceed the upper action level for the period of
' !
time specified in the BMP Plan, the mill must complete corrective action to bring the
wastewater treatment system influent mass loading below the lower action level as soon as
practicable.
(3) Although exceedances of the action levels will not constitute violations of an
NPDES permit or pretreatment standard, failure to take the actions required by paragraph
(i)(2) of this section as soon as practicable will be a permit or pretreatment standard violation.
(4) Each mill subject to this section must report to the NPDES permitting or
pretreatment control authority the results of the daily monitoring conducted pursuant to
paragraph (i)(l) of this section. Such reports must include a summary of the monitoring
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results, the number and dates of exceedances of the applicable action levels, and brief
descriptions of any corrective actions taken to respond to such exceedances. Submission of
such reports shall be at the frequency established by the NPDES permitting or pretreatment
control authority, but in no case less than once per year.
(j) Compliance deadlines. (1) Existing direct and indirect dischargers. Except as
provided in paragraph (j)(2) of this section for new sources, indirect discharging mills subject
to this section must meet the deadlines set forth below. Except as provided in paragraph
(j)(2) of this section for new sources, NPDES permits must require direct discharging mills
subject to this section to meet the deadlines set forth below. If a deadline set forth below has
passed at the time the NPDES permit containing the BMP requirement is issued, the NPDES
permit must require immediate compliance with such BMP requirements).
(i) Prepare BMP Plans and certify to the permitting or pretreatment authority
that the BMP Plan has been prepared in accordance with this regulation not later than [insert
date 12 months after date of publication};
(ii) Implement all BMPs specified in paragraph (c) of this section that do not
require the construction of containment or diversion structures or the installation of
monitoring and alarm systems not later than [insert date 12 months after date of publication}'.
(iii) Establish initial action levels required by paragraph (h)(3) of this section
not later than [insert date 12 months after date of publication}.
(iv) Commence operation of any new or upgraded continuous, automatic
monitoring systems that the mill determines to be necessary under paragraph (c)(3) of this
section (other than those associated with construction of containment or diversion structures)
not later than [insert date 24 months after date of publication}.
(v) Complete construction and commence operation of any spent pulping
liquor, collection, containment, diversion, or other facilities, including any associated
continuous monitoring systems, necessary to fully implement BMPs specified in paragraph (c)
of this section not later than [insert date 36 months after date of publication}.
(vi) Establish revised action levels required by paragraph (h)(4) of this section
as soon as possible after fully implementing the BMPs specified in paragraph (c) of this
section, but not later than [insert date 45 months after date of publication}.
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(2) New Sources. Upon commencing discharge, new sources subject to this section
must implement all of the BMPs specified in paragraph (c) of this section, prepare the BMP
Plan required by paragraph (d) of this section, and certify to the permitting or pretreatment
authority that the BMP Plan has been prepared in accordance with this regulation as required
by paragraph (f) of this section, except that the action levels required by paragraph (h)(5) of
this section must be established not later than 12 months after commencement of discharge,
based on six months of monitoring data obtained prior to that date in accordance with the
procedures specified in paragraph (h)(2) of this section.
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