DRAFT
Development Document for
Effluent Limitations Guidelines
and Standards of Performance
PULP, PAPER, AND
PAPERBOARD INDUSTRY
• Prepared by Wapora, Inc.
J for the
oi -r United States
5 S Environmental Protection Agency
o
Under Contract Number 68-01-1514
Dated: June 1973
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NOTICE
The attached document is a DRAFT CONTRACTOR'S REPORT. It includes
technical information and recommendations submitted by the Contrac-
tor to the United States Environmental Protection Agency ("EPA")
regarding the subject industry. It is being distributed for review
and comment only. The report is not an official EPA publication and
it has not been reviewed by the Agency.
The report, including the recommendations, will be undergoing exten-
sive review by EPA, Federal and State agencies, public interest
organizations and other interested groups and persons during the
coming weeks. The report, and in particular the contractor's rec-
ommended effluent limitations guidelines and standards of performance,
is subject to change in any and all respects.
The regulations to be published by EPA under Sections 304(b) and 306
of the Federal Water Pollution Control Act, as amended, will be
based to a large extent on the report and the comments received on it.
However, pursuant to Sections 304(b) and 306 of the Act, EPA will also
consider additonal pertinent technical and economic information which
is developed in the course of review of this report by the public and
within EPA. EPA is currently performing an economic impact analysis
regarding the subject industry, which will be taken into account as
part of the review of the report. Upon completion of the review pro-
cess, and prior to final promulgation of regulations, an EPA report
will be issued setting forth EPA's conclusions concerning the subject
industry, effluent limitations guidelines and standards of performance
applicable to such industry. Judgments necessary to promulgation of
regulations under Sections 304(b) and 306 of the Act, of course,
remain the responsibility of EPA. Subject to these limitations, EPA
is making this draft contractor's report available in order to en-
courage the widest possible participation of interested persons in
the decision making process at the earliest possible time.
The report shall have standing in any EPA proceeding or court proceed-
ing only to the extent that it represents the views of the Contractor
who studied the subject industry and prepared the information and
recommendations. It cannot be cited, referenced, or represented in
any respect in any such proceedings as a statement of EPA's views
regarding the subject industry.
U.S. Environmental Protection Agency
Office of Air and Water Programs
Effluent Guidelines Division
Washington, D.C. 20460
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ERRATA
Beginning with Referenc
each reference cited in the text
lower number in the
e XXIV in the text,
thereafter corresponds to the next
reference list.
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DEVELOPMENT DOCUMENT FOR
EFFLUENT LIMITATIONS GUIDELINES
AND STANDARDS OF PERFORMANCE
FOR THE
PULP, PAPER, AND PAPERBOARD INDUSTRY
Prepared For
The
United States Environmental Protection Agency
June 1973
WAPORA, Inc.
6900 Wisconsin Avenue
Bethesda, Maryland 20015
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QRaft
ABSTRACT
This document presents the findings of an extensive study of a segment
of the pulp and paper industry by WAPORA, Inc. for the purpose of rec-
ommending to the United States Environmental Protection Agency effluent
limitations guidelines and standards of performance in compliance with
Sections 304(b) and 306 of the Federal Water Pollution Control Act
Amendments of 1972 (the "Act").
The subcategories of pulp and paper mills included in this study were
unbleached kraft, kraft~NSSC (with cross-recovery), NSSC sodium base,
NSSC ammonia base and waste paperboard.
Effluent limitations guidelines are set forth for the degree of effluent
reduction attainable through the application of the "Best Practicable
Control Technology Currently Available", and the "Best Available Tech-
nology Economically Achievable", which must be achieved by existing
point sources by July 1, 1977 and July 1, 1983, respectively. The "New
Source Standards of Performance" sets forth the degree of effluent
reduction which is achievable through the application of the best avail-
able demonstrated control technology, processes, operating methods, or
other alternatives. The proposed guidelines recommend biological waste
treatment as the base technology for 1977, and major internal mill
improvement, biological waste treatment and physical-chemical waste
treatment as the base control and treatment technologies both for 1983
and new sources.
Supportive data and rationale for development of the proposed effluent
limitations guidelines and new source performance standards are con-
tained in this report.
iii
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DfZ$ •
CONTENTS
Section Page
I. CONCLUSIONS 1
II. RECOMMEND AT IONS 3
III. INTRODUCTION ..... 7
Purpose and Authority 7
Summary of Methods Used for Development of
the Effluent Limitations Guidelines and
Standards of Performance 8
General Description of Industry Segments. .... 9
Products 10
Daily Capacity and Distribution 10
Annual Production 13
Pulp and Paper Making Processes . 16
Unbleached Kraft ..... 16
NSSC Process 19
Sodium Base NSSC - Kraft Mills With Cross
Recovery 24
Waste Paperboard 26
IV. SUBCATEGORIZATION OF THE INDUSTRY 29
Factors of Consideration 29
Rationale for Selection of Subcategories. .... 30
Raw Materials. 30
Production Processes 30
Products Produced 31
Age and Size of Mills 31
Geographical Locations 31
V. WATER USE AND WASTE CHARACTERIZATION 33
Wood Preparation 33
Pulping Processes 36
Neutral Sulfite Semi-Chemical 36
Unbleached Kraft 45
Waste Paperboard Mills 50
Paper Machines 53
v
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CONTENTS (Continued)
Section Page
VI. SELECTION OF POLLUTANT PARAMETERS 55
Wastewater Parameters of Significance 55
Rationale for Selection of Identified
Parameters 55
Biochemical Oxygen Demand. „ 55
Suspended Solids 55
PH ....... 55
Color 5g
Nitrogen ^
Other Parameters Indicating Presence of
Pollutants «... 55
VII. CONTROL AND TREATMENT TECHNOLOGIES 57
Summary 57
In-Plant Measures 1 57
Unbleached Kraft 62
Sodium Base Neutral Sulfite Semi-Chemical. . .
Ammonia Base Neutral Sulfite Semi-Chemical . . gg
Waste Paperboard gg
External Treatment Technology 72
Removal of Suspended Solids 72
BOD Reduction . 73
Sludge Dewatering and Disposal 79
By-Product Usage 83
Irrigation and Land Disposal of Effluents .... 85
Kraft Linerboard Mill Applications 85
NSSC Corrugating Board Mills 86
Waste Paperboard Mill 86
Color Removal 87
Sources of Color 87
Lime Treatment 89
Other Color Removal Systems 91
Comparison of System Efficiency 93
Operation Considerations 95
vi
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CONTENTS (Continued)
Section Page
VII. Advanced Waste Treatment 102
(contd)
Introduction 102
Turbidity and Colloidal and Suspended Solids . 103
Dissolved Salts and Dissolved Solids 107
Trace Refractory Organics 112
Monitoring 127
Flow Measurement ..... 127
Sampling 131
Analysis ....... 131
Records and Reporting 132
VIII. COSTS, ENERGY, NON-WATER QUALITY ASPECTS, AND
IMPLEMENTATION REQUIREMENTS 133
Costs 133
Energy Requirements 134
Non-Water Quality Aspects of Control and
Treatment Technologies 137
Air Pollution Potential 137
Noise Potential 138
Solid Wastes and Their Disposal 139
Byproduct Recovery 141
Implementation Requirements 142
Availability of Equipment 142
Availability of Construction Manpower. .... 148
Construction Cost Index 148
Land.Requirement 149
Time Required to Construct Treatment
Facilities 149
IX. BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY
AVAILABLE 151
Introduction 151
Effluent Reduction Attainable Through the
Application of Best Practicable Pollution
Control Technology Currently Available 152
vii
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CONTENTS (Continued)
IX. Identification of Best Pollution Control
(contd) Technology Currently Available 153
Internal Control 153
External Treatment 155
Rationale for the Selection of Best
Pollution Control Technology Currently
Available 156
Age and Size of Equipment and Facilities. . 156
Process Change 157
Engineering Aspects of Control
Technique Applications 157
Non-water Quality Environmental Impact. . . 157
Cost of Application in Relation to
Effluent Reduction Benefits 158
Processes Employed 158
X. BEST AVAILABLE TECHNOLOGY ECONOMICALLY
ACHIEVABLE 159
Introduction 159
Effluent Reduction Attainable Through the
Application of Best Available Technology
Economically Achievable 159
Identification of the Best Available
Technology Economically Achievable 161
Internal Controls . 161
External Treatment 162
Rationale for the Selection of Best
Available Technology Economically
Achievable 162
Age and Size of Equipment and Facilities. . 162
Process Changes 163
Engineering Aspects of Control Technique
Applications 163
Non-water Quality Environmental Impact. . . 163
Cost of Application in Relation to
Effluent Reduction Benefits 164
Processes Employed. . 164
viii
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CONTENTS (Continued)
Section Page
XI. NEW SOURCE PERFORMANCE STANDARDS 167
Introduction 167
Effluent Reduction Attainable Through the
Application of New Source Performance
Standards 167
Identification of Technology for New Source
Performance Standards 169
Rationale for Selection of Technology for
New Source Performance Standards 169
Type of Process Employed and
Process Changes 169
Operating Methods 169
Batch as Opposed to Continuous
Operations 169
Use of Alternative Raw Materials and
Mixes of Raw Materials 170
Use of Dry Rather than Wet Processes
(Including Substitution of Recoverable
Solvents for Water) 170
Recovery of Pollutants as Byproducts .... 170
Pre-treatment Requirements for Discharges
to Municipal Systems 170
XII. ACKNOWLEDGEMENTS 171
XIII. REFERENCES 173
XIV. GLOSSARY 181
APPENDIX 187
ix
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FIGURES
Page
1 DISTRIBUTION OF UNBLEACHED KRAFT, NSSC, AND KRAFT 14
NSSC MILLS IN THE U.S. (1973)
2 DISTRIBUTION OF WASTE PAPERBOARD MILLS IN THE U.S. 15
(1973)
3 KRAFT PULPING PROCESS DIAGRAM 17
4 KRAFT RECOVERY SYSTEM PROCESS FLOW DIAGRAM 20
5 FOURDRINIER PAPER MACHINE PROCESS DIAGRAM 21
6 NEUTRAL SULFITE SEMI-CHEMICAL PULP PROCESS 23
DIAGRAM
7 PROCESS FLOW DIAGRAM OF SPENT LIQOUR RECOVERY SYSTEMS 25
AT COMBINED KRAFT -NSSC MILLS
8 WASTE PAPERBOARD MILL PROCESS DIAGRAM 27
9 LONG TERM BOD OF BARKER EFFLUENT 38
10 SETTLING RATE OF BARKER SCREENING EFFLUENT 40
11 BOD LOAD OF NSSC PULPING 42
12 SUSPENDED SOLIDS LOSSES FROM NSSC PULPING 43
13 PROCESS FLOW AND MATERIAL DIAGRAM FOR A 250 46
TON-A-DAY NSSC MILL
14 RELATIONSHIP BETWEEN TOTAL SOLUBLE SOLIDS, BOD, 47
CONDUCTANCE & LIGHT ABSORPTION IN KRAFT PULPING
DECKER FILTRATE EFFLUENT
15 PROCESS FLOW AND MATERIALS DIAGRAM FOR A 1,000 49
TON-A-DAY KRAFT LINERBOARD MILL
16 PROCESS FLOW AND MATERIALS DIAGRAM OF A WASTE 51
PAPERBOARD MILL
17 EFFLUENT TREATMENT AT NEUTRAL SULFITE SEMI-CHEMICAL 74
CORRUGATING BOARD MILLS THAT INCINERATE SPENT COOKING
LIQUOR
18 PROCESS FLOW DIAGRAM OF LINERBOARD MILL EFFLUENT 76
TREATMENT
xi
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19
20
21
22
23
24
25
26
27
28
29
30
31
32
80
84
90
92
96
121
128
129
130
143
14*
146
147
150
EFFLUENT TREATMENT AT WASTE PAPERBOARD MILLS
SLUDGE DEWATERING AND DISPOSAL
MASSIVE LIME PROCESS FOR COLOR REMOVAL
EFFLUENT TREATMENT PILOT PLANT
COLOR REMOVAL IN LIME TREATMENT AS A FUNCTION OF
SOLUBLE Ca IN WATER
ECONOMY IN SCALE - CARBON ABSORPTION SYSTEMS
EFFECTS OF TOWER DEPTH ON AMMONIA REMOVAL
EFFECTS OF HYDRAULIC LOADING ON AMMONIA REMOVAL
AT VARIOUS DEPTHS
EFFECTS ON PACKING SPACING ON AMMONIA REMOVAL
TOTAL WATER POLLUTION CONTROL EXPENDITURES
WASTEWATER TREATMENT EQUIPMENT SALES
ENGINEERING NEWS RECORD CONSTRUCTION COST INDEX
LAND REQUIRED FOR WASTE WATER TREATMENT
TIME REQUIRED TO CONSTRUCT WASTE WATER FACILITIES
CONVENTIONAL & TURNKEY CONTRACTS
xli
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TABLES
Page
1 Classification by SIC Code of Unbleached Kraft, NSSC,
and Waste Paperboard Products 11
2 Wood Washing 33
3 Analysis of Wet Drum Barking Effluents 35
4 Analysis of Hydraulic Barking Effluents 37
5 Sewer Losses From Wet Barking Operations 39
6 Neutral Sulfite Corrugating Boardmill Effluent
Characteristics 44
7 Waste Paperboard Mill Waste Loadings 52
8 Reuse of Effluent From Different Unit Operations 64
9 Values for Color Discharged from Various Pulping
Processes 88
10 Unit Process Flow and Color Distribution in Individual
Kraft Pulping Effluents 88
11 Color Removal in Biological Oxidation - Carbon
Adsorption Sequence at 15 GPM 94
12 Color Removal By Primary Clarification - Carbon
Adsorption Sequence 94
13 Color Removal By Time Treatment - Carbon Adsorption
Sequence at Soluble Calcium Range of 69-83 mg/1 97
14 Removal of Color and TOC By FACET Carbon Adsorption
Following Lime Treatment for 12~Day Period 98
15 Waste Water Renovation - Summary of Results 99
16 Renovated Water Analysis - Unbleached Kraft Linerboard
Total Mill Effluent (Pilot Plant Run No. 1) 100
17 Renovated Water Analysis - Unbleached Kraft Linerboard
Total Mill Effluent (Pilot Plant Run No. 2) 101
18 Summary of Results of Treatment By Reverse Osmosis 106
xiii
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TABLES
(cont .d)
Page
19 Total Solids Removal - Reverse Osmosis 109
20 Behavior of Major Chemical Constituents in Renovation
System 111
21 Pretreatment Requirements for Ion Exchange 113
22 Results of Granular Activated Carbon Column Pilot
Plant Treating Unbleached Kraft Mill Waste 115
23 Results of Activated Carbon Pilot Plants Treating
Unbleached Kraft Mill Effluent 119
24 Treatment Costs I35
25 Power Costs 136
xiv
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DRAFT
SECTION I
CONCLUSIONS
Notice
This document is a preliminary draft. The conclusions
which have been reached reflect the technical judgment
of WAPORA, Inc. based on information developed in con-
junction with our subcontractors, and with the assis-
tance of the Environmental Protection Agency and the
cooperation of the National Council of the Pulp and
Paper Industry on Air and Stream Improvement. It is
being circulated for comment on its technical accuracy
and policy implications.
For the purpose of establishing effluent limitations guidelines and stan-
dards of performance, the segments of the pulp and paper industry which
were studied have been subcategorized as follows:
Unbleached Kraft
Neutral Sodium Sulfite Semi-Chemical (NSSC) - Sodium Base
NSSC - Ammonia Base
Kraft - NSSC (with cross-recovery)
Waste Paperboard
Within each identified subcategory, factors such as age, size of plant,
process employed, climate, and waste treatability confirm and sub-
stantiate this subcategorization for the purpose of establishing ef-
fluent limitations and performance standards to be achieved through
the application of recommended treatment and control technologies.
At this time, some mills within each subcategory are achieving the 1977
requirement of best practicable technology currently available. It is
estimated that increases in production costs to achieve this level will
range from less than $1.00 per ton up to $14.00 per ton depending upon
specific mill conditions relating to available technologies at that
location. This technology level suggests biological waste treatment as
the basic treatment process and limitations on BOD^, suspended solids,
and pH range are set forth.
Best available technology economically achievable is a requirement for
1983, and a few mills in the subcategories studied are currently
achieving this for most identified pollutants. The estimated increases
in production costs of upgrading existing mills from the 1977
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
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DRAFT
requirements to those of 1983 range from less than $1.00 per ton up to
$7.00 per ton, depending on specific mill conditions. This technology
level suggests major internal mill improvements, biological waste treat-
ment, and some physical-chemical waste treatment as the basic treatment
and control technologies, and limitations on BOD5, suspended solids, pH
range, color, and nitrogen are set forth.
New source performance standards are proposed which reflect internal im-
provements which can be achieved through effective design and layout of
mill operations. Standards are set forth on BOD^, suspended solids, pH
range, color, and ammonia at levels above those cited for existing
mills by 1977. The basic treatment and control processes which are
suggested as a means of meeting these performance standards are similar
to those Dronosfid for pxisfinp mills hv
2
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
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DRAFT
SECTION II
RECOMMENDATIONS
INTRODUCTION
Based upon the information shown in the body of this report, the follow-
ing effluent limitations guidelines and standards of performance are rec-
ommended for the subcategories studied.
The allowable pounds of pollutants per ton of production are to be based
upon monthly averages of daily values as determined from industrial re-
cords. It is expected that values on any given day could exceed these
guidelines. Further, values may be adjusted to reflect variations in i .
performance as a result of changes in materials mix, ambient air temper- S&ftufltl) «•
ature effprt on wasfp treatment .process performed, and other local con-
ditions.
Production capacity is defined as the total production off the machine,
including reprocessed broke. Daily production, in air-dry tons, is de-
fined as the highest average level sustained for seven consecutive opera-
ting days of normal production.
Values are intended to reflect the net pounds per ton of product which
are attributed to the industrial operation, and do not account for
"background" pollutional loads which may have existed in the process
water prior to use by the industry.
BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY AVAILABLE
Recommended Effluent Guidelines, L 'L. 0
Pounds Per Short Ton of Production /vkCaUA um<»
Subcategory BOD^ Suspended Solids pH Range
Unbleached Kraft
4.0
6.0
7.5-8.5
NSSC-Sodium Base
10.0
10.0
7.2-7.8
NSSC-Ammonia Base
10.0
I—4
o
o
7.2-7.8
Kraft-NSSC
(with cross recovery)
7.0
7.0
7.5-8.5
Waste Paperboard
2.0
2.0
6.0-7.5
3
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
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DRAFT
BEST AVAILABLE TECHNOLOGY ECONOMICALLY FEASIBLE
Recommended Effluent Guidelines,
Pounds Per Short Ton of Production
^xrtuso
Subcategory
bod5
Suspended
Solids
pH Range
Color
Unbleached Kraft
2.0
3.0
7.5-8.5
12.0
NSSC-Sodium Base
3.5
5.0
ho
1
00
7.0
NSSC-Ammonia Base
3.5
5.0
7.2-7.8
7.0
'liraf t-NSSC
3.5
3.5
7.5-8.5
8.0
(with cross recovery)
Waste Paperboard
1.0
1.0
6.0-7.5
N/A
In addition, effluent limitation guidelines are recommended for nitro-
gen on NSSC ammonia base mills. However, no specific limitation has
been established because of the extreme restriction at this time on
meaningful data. Currently, only two such mills exist and preliminary
indications are that discharges in the range of 7.5-10.0 kilograms per
metric ton (15-20 pounds per short ton) can occur. No technology for
the removal of nitrogen has been applied within the pulp and paper in-
dustry, and only very limited technology has been applied in other in-
dustries, especially at the concentrations cited. Further, the allow-
able limitations are to a large degree dependent upon local conditions.
Extensive studies on effective methods for the removal of nitrogen must
be carried out as a means of establishing effluent limitations. Assum-
ing that adequate technology exists at the time, limitations of 2 kilo-
grams per metric ton (4 pounds per short ton) or less should be imposed.
4
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
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DRAFT
RECOMMENDED NEW SOURCE STANDARDS OF PERFORMANCE
Pounds Per Short Ton of Production
Subcategory BOD5 Suspended pH Range Color
Solids
Unbleached Kraft
3.5
5.0
7.5-8.5
25.0
NSSC-Sodium Base
5.0
6.0
7.2-7.8
20.0
NSSC-Ammonia Base
5.0
6.0
7.2-7.8
20.0
Kraf t-NSSC
4.5
6.0
7.5-8.5
22.0
(with cross recovery)
Waste Paperboard
1.5
1.5
6.0-7.5
N/A
In addition, new source standards of performance are recommended for
nitrogen on NSSC ammonia base mills. However, no specific limitation
has been established because of the extreme restriction at this time on
meaningful data. Currently, only two such mills exist and preliminary
indications are that discharges in the range of 7.5-10.0 kilograms per
metric ton (15-20 pounds per short ton) can occur. No technology for
the removal of nitrogen has been applied within the pulp and paper in-
dustry, and only very limited technology has been applied in other in-
dustries, especially at the concentrations cited. Further, the allow-
able limitations are to a large degree dependent upon local conditions.
Extensive studies on effective methods for the removal of nitrogen
must be carried out as a means of establishing performance standards.
Assuming adequate technology exists at the time, limitations of 4.0-
6.0 kilograms per metric ton (eight-12 pounds per short ton) or less
should be imposed.
/food Dftitflfi/i (KjmmjdV 1st !
5
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
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SECTION III
INTRODUCTION
PURPOSE AND AUTHORITY
Section 301(b) of the Federal Water Pollution Control Act, as amended
in 1972, requires the achievement by not later than July 1, 1977, of
effluent limitations for point sources, other than publicly owned
treatment works, which are based on the application of the best practi-
cable control technology currently available as defined by the Adminis-
trator pursuant to Section 304(b) of the Act. Section 301(b) also
requires the achievement by not later than July 1, 1983, of effluent
limitations for point sources, other than publicly owned treatment
works, which are based on the application of the best available tech-
nology economically achievable which will result in reasonable further
progress toward the national goal of eliminating the discharge of all
pollutants, as determined in accordance with regulations Issued by the
Administrator pursuant to Section 304(b) of the Act.' Section 306 of
the Act requires the achievement by new sources of a federal standard
of performance providing for the control of the discharge pollutants
which reflects the greatest degree of effluent reduction which the
Administrator determines to be achievable through the application of
the best available demonstrated control technology, processes, opera-
ting methods, or other alternatives, Including, where practicable, a
standard permitting no discharge of pollutants.
Section 304(b) of the Act requires the Administrator to publish within
one year of enactment of the Act, regulations providing guidelines for
effluent limitations setting forth the degree of effluent reduction
attainable through the application of the best control measures and
practices achievable including treatment techniques, process and pro-
cedure innovations, operation methods, and other alternatives. The
regulations proposed herein set forth effluent limitations guidelines
pursuant to Section 304(b) of the Act for the unbleached kraft, neutral
sulfite semi-chemical (NSSC), and waste paperboard segments of the pulp,
paper, and paperboard point source categories.
Section 306 of the Act requires the Administrator, within one year af-
ter a category of sources is included in a list published pursuant to
Section 306(b)(1)(A) of the Act, to propose regulations establishing
federal standards of performance for new sources within such catego-
ries. The Administrator published in the Federal Register of January 16,
1973, (38 F.R. 1624), a list of 27 source categories. Publication of
the list constituted announcement of the Administrator's intention of
establishing, under Section 306, standards of performance applicable to
new sources within the pulp, paper, and paperboard point source cate-
gories, which were included within the list published January 16, 1973.
7
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This report proposes such standards for the unbleached kraft, neutral
sulfite semi-chemical, and waste paperboard segments of these point
source categories.
SUMMARY OF METHODS USED FOR DEVELOPMENT OF THE EFFLUENT LIMITATIONS
GUIDELINES AND STANDARDS OF PERFORMANCE
The effluent limitations guidelines and standards of performance pro-
posed herein were developed in the following manner. The point source
category was first subcategorized for the purpose of determining whether
separate limitations and standards are appropriate for different seg-
ments within a point source category. Possible subcategorization was
evaluated upon raw material used, product produced, manufacturing pro-
cess employed, and other factors. The raw waste characteristics for
each resultant subcategory were then identified. This included an
analysis of 1) the source and volume of water used in the process em-
ployed and the sources of waste waters in the plant and 2) the con-
stituents (including thermal) of all waste waters including toxic con-
stituents and other constituents which result in taste, odor, and color
in water or aquatic organisms. The constituents of waste waters which
should be subject to effluent limitations guidelines and standards of
performance were identified.
The full range of control and treatment technologies existing within
each subcategory was identified. This included an identification of
each distinct control and treatment technology, including both inplant
and end-of-process technologies, which are existent or capable of being
designed for each subcategory. It also included an identification in
terms of the amount of constituents (including thermal) and the chemi-
cal, physical, and biological characteristics of pollutants, of the
effluent level resulting from the application of each of the treatment
and control technologies. The problems, limitations, and reliability
of each treatment and control technology and the required implementa-
tion time were also identified. In addition, the non-water quality
environmental impact, such as the effects of the application of such
technologies upon other pollution problems, including air, solid waste,
noise, and radiation were also identified. The energy requirements of
each of the control and treatment technologies were identified as well
as the cost of the application of such technologies.
The information, as outlined above, was then evaluated in order to de-
termine what levels of technology constitute the "best practicable
control technology currently available;" "best available technology
economically achievable;" and the "best available demonstrated control
technology processes, operating methods, or other alternatives." In
identifying such technologies, various factors were considered. These
included the total cost of application of technology in relation to the
effluent reduction benefits to be achieved from such application, the
age of equipment and facilities involved, the process employed, the
8
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engineering aspects of the application of various types of control
techniques or process changes, non-water quality environmental impact
(including energy requirements), and other factors.
The extensive data base for identification and analyses was derived
from a number of sources. These sources included EPA research and
demonstration project Information, including previous EPA industrial
waste and state-of-the-art treatment studies of the pulp and paper in-
dustry; published literature; Refuse Act Permit Program (RAPP) applica-
tions; and National Council of the Pulp and Paper Industry for Air and
Stream Improvement NCASI). This data base was verified by on-site
surveys of 17 mills of which 12 included sampling and analysis of waste
streams conducted during the term of this contract. References used in
developing the guidelines for effluent limitations and standards of
performance for new sources reported herein are included in Section XIII
of this document.
GENERAL DESCRIPTION OF INDUSTRY SEGMENTS
Paper is made from raw materials which contain adequate amounts of
cellulose fiber, its basic component. The cellulose fibers must first
be separated from other constituents of the fiber source and flberlzed.
This function is the pulping process. During the 19th century, the use
of wood began to supplant cotton and linen rags, straw, and other less
plentiful fiber sources. Today, it accounts for over 98 percent of the
virgin fiber used in papermaklng.
There are several methods used for pulping wood. In some, it is cooked
with chemicals under controlled conditions of temperature, pressure,
time and liquor composition (1). The various processes utilize differ-
ent chemicals or combinations of them. In other methods, wood is
reduced to a fibrous state by mechanical means or a combination of
chemical and mechanical action. The repulping of waste paper is a
hydraulic and mechanical process.
r.ue early use of kraft pulping, an alkaline chemical process, was con-
current with the ascendancy of wood as a paper raw material. The pro-
cess was first patented in this country more than 100 years ago and is
currently the dominant pulping method. This position was achieved
largely for two reasons: 1) Recovery, because of the cost of the chemi-
cals utilized, is an economic necessity to the process and in the 1930's
successful chemical recovery techniques were applied; 2) The process
was found to be adaptable to nearly all wood species and its application
to southern yellow pines, which were unsuitable for other processes,
resulted in a rapid expansion of kraft pulping (2).
The principles basic to the neutral sulfite semi-chemical process —
1) chemical treatment of chips followed by grinding or fiberizing and
2) cooking with a neutral or slightly alkaline sodium sulfite solution —
9
-------
were also advanced in the 19th century. However, it was not until their
advantages were demonstrated in the 1920's at the U.S. Forest Products
Laboratory that the first NSSC mill began operation in 1925 for the
production of corrugating board (2). The process gained rapid accep-
tance particularly because of its ability to utilize the vast quanti-
ties of inexpensive hardwoods previously considered unsuitable for
producing quality pulps (3). Also, the quality of stiffness which hard-
wood NSSC pulps impart to corrugating board (2), and the large demand
for this material, have promoted a rapid expansion of the process.
The future of NSSC pulping is closely tied to the development of eco-
nomic systems for chemical recovery or non-polluting chemical disposal.
In the past, the small size of the mills, the low organic content and
heat value of the spent liquor, and the low cost of cooking chemicals
provided little incentive for large capital investment for recovery
plants (2).
Waste paper has been recycled in this country since the mid-1850's.
Today, about 21 percent of the paper and paperboard produced is reused
as a raw material for new products. In 1972, 11.4 million metric tons
(12.6 million short tons) were reclaimed. Waste paperboard mills con-
sumed about 75 percent of this total (4).
Products
Unbleached kraft pulps are particularly suitable for producing liner-
board, a paperboard used as the smooth surface facing in "corrugated"
boxes, wrapping paper, and paper for grocery bags and shipping sacks.
About 95 percent of NSSC pulp is used to manufacture the corrugated
medium for corrugated boxes but it is also a component of other prod-
ucts which do not require the maximum tearing resistance or folding
endurance such as white paper and newsprint (2). Waste paperboard is
most familiar in a wide variety of commercial packaging which does re-
quire a folding capability, such as bottle carriers.
An expanded itemization of the products of these industrial segments
appears in Table 1. This list, from the Bureau of the Census, Census of
Manufactures, groups the products according to Standard Industrial
Classifications and Illustrates product versatility. "Combination
paperboard" is the Census term for waste paperboard which refers to the
fact that although waste paper is the primary furnish, a small per-
centage of virgin pulp is frequently used.
Daily Production Capacity and Distribution
1973 industry data show that there are approximately 29 mills in the
U.S. which produce nothing other than unbleached kraft pulp and paper
and/or paperboard. Their total dally capacity is about 18,140 metric
10
-------
TABLE 1
CLASSIFICATION BY SIC CODE OF
UNBLEACHED KRAFT, NSSC, AND WASTE PAPERBOARD PRODUCTS
SIC Product Code Product
2621
26217
26217 10
26217 30
26217 50
26217 60
26216
26216 01
26216 14
26216 17
26216 29
2631
26311
26311 10
26311 30
26311 50
26311 70
26311 90
26313
26313 10
26313 30
26314
26314 10
26314 30
26314 50
Papermill products, except building paper
Unbleached kraft packaging & industrial converting
paper
Wrapping
Shipping sack
Bag & sack, other than shipping sack
Other converting (18 pounds and over)
Coarse paper
Unbleached kraft paper:
Wrapping
Shipping sack
Bag & sack (other than shipping sack)
Other converting (18 pounds and over)
Paperboard mill products
Unbleached kraft packaging & industrial converting
paperboard
Unbleached linerboard
Corrugating medium
Folding carton type paperboard
Tube, can & drum paperboard
Other unbleached packaging & industrial converting
kraft paperboard
Semi-chemical paperboard
Corrugating medium
Other semi-chemical paperboard
Combination paperboard: Shipping containerboard
Linerboard
Corrugating medium
Container chip and filler board
Continued - next page
11
-------
TABLE 1. Contd.
26315
26315
10
26315
30
26315
50
26315
70
26315
90
26316
26316
10
26316
30
26316
50
26316
60
26317
26317
30
26317
50
26317
70
26317
90
Combination paperboard: Bending
Bending chip
Kraftlined
Whitelined
Clay coated
Other combination bending paperboard
Combination paperboard: Nonbending
Plain chip
Newsllned
Whitelined
Other combination nonbending paperboard
Special combination packaging & Industrial con-
verting paperboard
Gypsum linerboard
Tube, can & drum stock
Fanelboard & vallboard stock
Other special combination packaging & indus-
trial converting paperboard
12
-------
tons (20,000 short tons) for pulp and nearly 22,675 metric tons (25,000
short tons) for paper and board production. Twenty-one separate NSSC
mills with a total daily capacity of 5455 metric tons (6025 short tons)
for producing pulp and 6004 metric tons (6620 short tons) for paper and
board are recorded. The total daily capacity of eight unbleached kraft
and NSSC mills operating at the same site is as follows:
Kraft pulp — 8492 metric tons (9363 short tons)
NSSC pulp — 1971 metric tons (2173 short tons)
Paperboard — 9452 metric tons (10,421 short tons approx.)
One hundred and thirty-eight waste paperboard mills having a dally pro-
duction capacity of about 19,047 metric tons (21,000 short tons) are
also shown.
Mills which fall within these segments of the pulp and paper Industry
are listed in Appendix 1.
The size range of these mills in terms of paper and board capacity is:
Unbleached kraft — 181 metric tons (200 short tons to
1701 metric tons (1875 short tons)
NSSC — 91 metric tons (100 short tons) to
635 metric tons (700 short tons)
Vaste paperboard — 13.6 metric tons (15 short tons) to
907 metric tons (1000 short tons)
One 771-metric ton (850-short ton) unbleached kraft pulp mill, which is
of median size, consumes approximately 1200 cords of wood dally. An
"average" 227-metric ton (250-short ton) NSSC utilizes about 100 cords
per day.
The geographic distribution of the kraft and NSSC mills, and that of the
joint kraft-NSSC operations, is shown in Figure 1. Figure 2 illustrates
the distribution of the waste paperboard mills.
Annual Production
A total of over 15.4 million metric tons (17 million short tons) of un-
bleached kraft pulp and nearly 3.6 metric tons (4 million short tons) of
NSSC pulp were produced in the U.S. in 1972 according to preliminary
American Paper Institute (API) statistics. Total unbleached kraft paper
and paperboard production was 15.6 metric tons (17.2 million short tons);
NSSC paperboard, 3.6 million metric tons (4.0 million short tons); and
waste paperboard 6.9 metric tons (7.6 million short tons) (5). These
totals Include production of mills which manufacture other products in
addition to those to which this report is addressed.
13
-------
Figure 1
DISTRIBUTION OF UNBLEACHED KRAFT, NSSC, AND KRAFT-NSSC MILLS IN THE U.S. (1973)
MINN
N DAK
S DAK.
IOWA
NEBR
COLO
KANS.
«• MEX
OKLA.
TEX.
dJ Unbleached Kraft
O NSSC
A Kraft-NSSC
-------
Figure 2
DISTRIBUTION OF WASTE PAPERBOARD MILLS IN THE U.S. (1973)
-------
Other products and segments of the industry will be covered in a subse-
quent report.
PULP AND PAPERMAKING PROCESSES
Unbleached Kraft
Wood, the fiber raw material of unbleached kraft pulp arrives at the
pulp mill as logs or as chips. Barked logs can be chipped directly for
use. Bark is removed from unbarked logs in a wet or dry process and the
logs are then chipped for conveyance to the digester, a large steel
pressure vessel heated with steam to about 150°C. Here the chips are
cooked in either a batch or continuous operation to dissolve ligrin and
separate the celluloslc fibers. The cooking liquor contains a mixture
of caustic soda and sodium sulfide, which necessitate, because of high
chemical costs and high liquor concentrations, a chemical recovery sys-
tem which is integral to the process. This system and its role in the
preparation of cooking liquor are described in ensuing paragraphs.
The unbleached kraft process is described as a "full-cook" process
since cooking is completed to the point at which the wood will be fiber-
ized upon being blown from the digester. In modern practice, the pulp
is ejected to a blowtank.
The pulp, along with the "spent cooking liquor" (called "black liquor"),
is then transferred to a "brown-stock" chest, or tank, and thence to
vacuum drum washers or continuous dlffusers where the "spent liquor" is
separated by counter-current washing. In older mills, the pulp is
"blown" directly to the diffusers from the digester.
Chemical recovery necessitates a high degree of liquor separation with
as little dilution as is possible to minimize heat requirements of
evaporation (2)(6). Three stages of washing, which may employ blow-
tank condensate reuse, are common but, in some cases, four are used. In
some newer installations a combination of vacuum washers and diffusers
is employed (7). Some continuous digesters contain liquor separation
and diffusion washing zones within the digester body and in some kraft
mills, the pulp is screened and/or refined prior to brown-stock washing
to effect certain economies in washing and improvements in pulp quality
(2).
After washing, the pulp is diluted and screened to remove knots, uncook-
ed chips, resin particles, etc., and is then ready for production of
unbleached paper and paperboard or thickening to a high consistency for
further processing, storage, or lapping for shipment.
The kraft pulping process is illustrated in Figure 3.
16
-------
FIGURE 3
KRAFT PULPING PROCESS DIAGRAM
LEGEND
CHEM. S LIQUORS
PROCESS WATER
BACK WATER
EFFLUENT
STEAM & GASES
REJECTS
BY-PRODUCTS
WOOD CHIPS
STEAM-
r~
i
i
I
i
TURPS *-
1
EFFLUENT
DIGESTER
TURP
RECOVERY
BLOW TANK
I OFF
I GASES
i a
HOT WATER
RECOVERY
WATER
FIBERIZER
KNOTTERS
BLACK
LIOUOR
SEAL
BOX
U — --REJECTS
WASHERS
_L
PULP
OFF
GASES
i
EVAPS.
k
TALLOIL
B. L.O.
T
AIR
EFFLUENT
~¦OFF GASES
PRECIPITATOR
1
RECOVERY
FURNACE
CONTACT
EVAP
[ 1
l
1
MIX TANK
¦H
PROCESS
WATER
DISSOLVING
TANK
CHEMICAL
MAKE - UP
I
|
DREGS -
DREGS
WASHER
n
i_
MUD
WASHER
u
-L.
•OFF GASES
SCRUBBER
WHITE LIQUOR
CLARIFIER
1
I
I
~
GREEN LIOUOR
CLARIFIER
1
I
I
*
— CAUSTICIZER
LIME KILN
SLAKER
LIME
GRITS
17
-------
Evaporation and Recovery of Heat and Chemicals
"Weak black liquor" comes from the washing operation and contains about
10 percent solids. In addition to the inorganic cooking chemicals, it
contains organic wood constituents separated in the pulping process.
The weak black liquor is concentrated to about 40 to 45 percent solids
in long-tube multiple-effect evaporators and the resulting viscous mass
is called "strong black liquor." This is then concentrated further to
a consistency of 60 to 65 percent solids in the recovery furnace con-
tact evaporator or in a concentrator.
Cooking chemicals lost in pulping and washing are replaced with make-up
chemical, usually sodium sulfate, or a residue with a high content of
this salt (8). Acid sludge from oil treatment, raffinate from by-pro-
duct production, NSSC waste liquor, and ash from incineration of NSSC
liquor are examples of such residues. Salts captured from the recovery
furnace stack gases are also reintroduced into the system. Sulfur and
caustic soda are sometimes used to adjust the sulfidity.
The strong black liquor is then burned and the heat recovered in an
especially designed boiler. During burning, the organic sodium com-
pounds are converted to soda ash and sulfates to sulfides on the floor
or reducing section of the furnace. The molten smelt of salts is
dissolved in water to form "green liquor." This is clarified by sedi-
mentation and then causticized with lime to convert the soda ash to
caustic soda. After causticizing, the combined Na2S - NaOH solution is
known as "white liquor." This is settled and sometimes filtered through
pressure filters, adjusted to the desired strength or concentration for
cooking with weak black liquor, and stored for use in the pulping pro-
cess.
The lime mud (calcium carbonate) obtained on settling this white liquor
is washed and dewatered on rotary vacuum filters or centrifuges and
burned in rotary or fluidized kilns to form quick lime. This is hy-
drated with green liquor in slakers for reintroduction to the recovery
cycle.
The following chemical equations describe the chemical recovery process
( 8):
Burning:
Na2S04 + 2 C
Na£ + CO2
Causticizing:
Na2CC>3 + Ca (OH) 2 NaOH + CaC03
Na2S + C02
Na2C03
18
-------
Reburning: (of mud)
CaCOg CaO + CO2
Slaking:
CaO + H20 Ca(0H)2
The recovery system is illustrated in Figure 4.
Unbleached Kraft Paper and Faperboard
Paper is made by depositing, from a dilute water suspension of pulp, a
layer of fiber on a fine screen which permits the water to drain through
but which retains the fiber layer (2). This layer is then removed from
the wire, pressed, and dried. Two general types of machines and varia-
tions thereof are commonly employed. One is the cylinder machine in
which the wire is placed on cylinders which rotate in the furnish, and
the other is the fourdrinier In which the furnish is deposited upon an
endless wire belt.
Generally, kraft paper is manufactured on fourdrinier machines and paper-
board on either fourdrinier or cylinder machines. The primary opera-
tional difference between the two is the flat sheet-forming surface of
the fourdrinier and the cylindrical-shaped mold of the cylinder machine.
However, the type of machine used has little bearing on the raw waste
load.
The water which drains through the paper machine is known as white water
and contains suspended fiber, pulp fines, and chemicals used as additives
in the paper or board. In the case of unbleached kraft products, few
additives are required other than alum and starch, and, in some bag and
sack stock, wet-strength resins. The manufacture of llnerboard involves
a minimum of additives. It is, therefore, common to reuse white water
from these operations, first in the paper and board making operation
itself, and then in the pulping process. Fiber is collected and returned
to the system.
The continuous paper sheet is sent through a series of pressing and dry-
ing machines before emerging as the basic product. A flow sheet of the
fourdrinier operation Is presented in Figure 5.
NSSC Process
There are three main features of the NSSC process (9):
1. Impregnation of hardwood chips with cooking liquor
19
-------
FIGURE 4
KRAFT RECOVERYSYSTEM
PROCESS FLOW DIAGRAM
STRONG
*
BLACK
LIQUOR
STORAGE
ELECTROSTATIC
PRECIPITATOR
T
trt
OFF
GASES
J.
_L
RECOVERY
FURNACE
SALT~I_
CAKE J
T
SALT CAKE
DISSOLVING
TANK
WATER
WEAK
WASH
WATER
GREEN
LIQUOR
CLARIFIER
DREGS
SCRUBBER
¦LIME
WASHER
GRITS
SLAKER
CAUSTICIZING
DREGS
WHITE
LIQUOR
CLARIFIER
I
FILTER
UNDERFLOW
FRESH
WATER
WHITE
LIQUOR
STORAGE
PRODUCT
WATER
CHEMICALS-
STEAM
20
-------
FOURDRINIER PAPER MACHINE
PROCESS DIAGRAM
PRODUCT
EFFLUENT
PROCESS
WATER
DRIER
SECTION
PRESS
SECTION
PULP
CHEST
RICH WHITE
WATER TANK
FOURDRINIER
SECTION
REFINERS
MACHINE
SCREENS
SAVE-ALL
MACHINE
CHEST
COUCH PIT
WIRE
PIT
FILTERED
WHITE WATER
TANK
LEGEND
PRODUCT & RAW MAT'L
PROCESS WATER
BACK WATER
EFFLUENT
21
-------
2. Cooking at high temperature
3. Mechanical fiberizing
While some mills buy the cooking chemical, it is more commonly prepared
on the premises by burning sulfur and absorbing it in soda ash or ammo-
nia, depending on which base is utilized. Newer mills employ continuous
digesters although a large percentage of NSSC pulping still occurs in
batch digesters which have been converted from other processes.
Maximum temperature is adjusted according to retention time in the
digester (9). A short cook, 10-20 minutes at approximately 200°C is
characteristic of screw digesters. In verticle or rotating spherical
digesters, a period of one to three hours at temperatures ranging from
160°-175°C is typical.
In some mills, the softened chips as they come from the digester are
compressed in one or more stages of screw pressing. This facilitates
maximum recovery of spent liquor and partial washing with minimum dilu-
tion (2). Either from this stage or directly from the digester they are
sent to a disk mill for fiberizing. The chips then undergo vacuum or
pressure washing, screening, and/or centrifugal cleaning. Digester re-
lief and blow gases are condensed, and In some mills the condensate is
used in pulp washing.
The pulp is conveyed to an agitated chest where it is diluted with white
water from the paper mill to the desired consistency for feed to the
secondary refiners servicing the papermaking operation. In making cor-
rugating board, a small percentage of repulped waste paper is added to
give the product desired characteristics.
The NSSC pulping process is Illustrated in Figure 6.
Recovery or Burning of Cooking Chemicals
Chemical recovery in the Bodium base NSSC process is considerably more
difficult than in the kraft process. The spent liquor is low in solids
with a relatively high proportion of inorganic to organic constituents,
and, thus, does not burn easily. Other factors which complicate recovery
are a relatively high liquor viscosity and relatively low sodium-to-
sulfur ratio (1).
Because of these factors many mills simply evaporate and burn the spent
liquor without recovery. Evaporation is commonly accomplished in multi-
ple-effect evaDorators. The concentrated liquor is burned for disposal
or recovery in a fluidized bed reactor or a specially designed furnace.
In sodium base mills, the fluidized bed combusion units produce sodium
sulfate which is suitable for use in kraft mill liquor systems.
22
-------
FIGURE 6
NEUTRAL SULFITE SEMI-CHEMICAL
PULP PROCESS DIAGRAM
CHIP
STORAGE
TO ATMOSPHERE
I
STEAM
COOKING
LIQUOR
1
STACK
GASES
SO*-CO£
r~"
DIGESTOR
<
ABSORBER
A
»
"
1
BLOW
TANK
SULFUR
DIOXIDE
1
1
i
i
1
1
REFINERS
SODIUM
CARBONATE
STOCK
PREP.
WASHER
1
WHITE
EVAPORATOR
SHREDDER
WATER TANK
LIQUOR
RECOVERY OR
BURNING
PAPER MACH.
SAVE-ALL
PRODUCT
PROCESS
WATER
EFFLUENT
COND.
EVA P.
FLOOR DRAINS
WASHOUTS
OVERFLOWS
PRODUCT 8 RAW MATL.
CHEM. a LIQUORS
PROCESS WATER
BACK WATER
STEAM & GASES
EFFLUENT
COOLING HtO
23
-------
*»%
Recovery of sodium base NSSC liquor alone is presently limited to a few
large mills. The simplest recovery practice for these mills is to send
the liquor to a nearby kraft recovery system which is called cross-
recovery.
No successful system has been developed for chemical recovery in ammo-
nia base NSSC mills. In the two mills utilizing this base, the spent
liquor is incinerated. The combustion products are gaseous with a negli-
gible residue of inorganic ash (10)(11).
Corrugating Medium
Corrugating board or medium Is manufactured on either a cylinder or four-
drinier machine. The machine molds the corrugation into the paper in
the wet stage of the process so as to vary paper thickness at the corru-
gations (12). The sheet is more crush-resistant than that obtained in
the old method of crimping a uniform-thickness sheet in a secondary
operation.
Sodium Base NSSC-Kraft Mills with Cross Recovery
As noted above, the simplest and most economic solution to the sodium
base NSSC recovery problems is cross recovery with an adjacent kraft
mill. Such a joint operation Is also feasible In that both elements of
boxboard — linerboard and corrugating medium — are produced at the
same site (1). In addition, the NSSC liquors replace the salt cake
(sodium sulfate) used as make-up in the kraft cooking liquor.
At a three to one or greater ratio of kraft to NSSC production, all of
the NSSC spent liquor can be absorbed efficiently in the kraft recovery
system (9). This can, of course, be a drawback in limiting NSSC mill
size. On the other hand, this arrangement may be the only feasible
course in the future for small NSSC mills for which elaborate indepen-
dent recovery systems are economically out of the question.
Problems which have been encountered with handling NSSC spent brown
liquor in a kraft system are:
1. Lower solids content
2. Lower heat value
3. Increased scaling in evaporation
4. Increased liquor viscosity
5. Interference with byproduct recovery
Because of the corrosion problem in the evaporators some mills evaporate
the two separately. However, they are handled together successfully at
some Installations. The alternative methods are illustrated in Figure 7.
24
-------
N5
Ln
KRAFT PULP
WASHERS
WEAK
BLACK LIQUOR
600 TON
PULP EQUIVALENT
CHEMICAL
MAKE-UP
FIGURE 7
PROCESS FLOW DIAGRAM OF
SPENT LIQUOR RECOVERY SYSTEMS AT
COMBINED KRAFT - NSSC MILLS
EVAPORATORS
STRONG
BLACK LIQUOR
RECOVERY
FURNACE
__JL_
SDISSOLVING
B TANK
NSSC
SPENT LIQUOR
200 TON
PULP EQUIVALENT
ALTERNATE
E
NSSC
EVAPORATORS
p*"r.a*
Sr
CAUSTIC
SYSTEM
4
KRAFT
WHITE LIQUOR
-------
The kraft recovery system Itself is not changed because of the addition
of the NSSC liquor. Operators simply monitor the controls and accom-
modate the input
Waste Paperboard
To convert waste paper to secondary fiber, waste paper, sufficient water
to provide desired consistency of four to six percent, and chemicals are
charged at a controlled rate to a pulper along with steam. In this
operation, the paper follows water circulating in a large open vat and
is repeatedly exposed to rotating impeller blades. Over a period of
time it is ripped, shredded, and finally defibered (13). The pulper
operation may be batch, continuous, or a combination of both. A junker
is usually attached which, through centrifugal action, collects and
removes extraneous solid materials and papers not suitable for use.
The stock is then passed to centrifugal cleaners, and finally to a thick-
ener which may be preceded by pressure screens. Reject material is
dewatered for disposal, and the stock is stored for use or goes directly
to the refiners which serve the paper machines.
The removal of modern contaminants found in waste paper, including
plastic containers, polystyrene packing material, and other plastic
coatings and lamlnants (13) has required some refinements to the basic
process. Some mills also have systems for dispersing the bituminous
asphalt found in some reclaimed laminated kraft bags. This type system
subjects the fiber to a heat and pressure environment in a press and
digester (8).
The paper forming section of the board machine, or wet end, employed
depends on the type of product made. Both fourdrinier and cylinder ma-
chines and some special devices as well are used (14). Variations and
exceptions occur throughout the Industry, although in general, a four-
drinier is used to make a single stock sheet and a cylinder machine a
multi-ply sheet or heavy board. During recent years, cylinder machines
have been replaced by variations of the so-called "dry-vat" principle
in order to produce a multi-stock sheet at higher speeds.
A process flow diagram of a typical waste paperboard mills is shown In
Figure 8.
26
-------
FIGURE 8
WASTE PAPER BOARD MILL
PROCESS DIAGRAM
r
WHITE
WATER
CHEST
SAVE-ALL
- STEAM
iL
PULPER
CLEANERS
THICKENER
DUMP
CHEST
REFINERS
MACHINE
CHEST
MACHINE
SCREENS
L
TT
FORMING
SECTION
MACHINE
PIT
EFFLUENT
CHEM.
JUNKER
TRASH
TO
DUMP
P
REJECTS
PROCESS
WATER
MIXING BOX
REJECTS
T"
t
d-
nziii
LINER
PULPER
1
DUMP
CHEST
REFINERS
MACHINE
CHEST
MIXING BOX
MACHINE
SCREENS
PRESS
SEC
ION
DRIER
SECTION
PRODUCT
LE6END
PROD. 8 RAW MATL
CHEMICALS
PROCESS WATER
BACK WATER
STEAM
REJECTS
EFFLUENT
27
-------
SECTION IV
SUBCATEGORY ZATION OF THE INDUSTRY
FACTORS OF CONSIDERATION
This study is concerned with the unbleached kraft, neutral sulfite semi-
chemical, and waste paperboard segments of the pulp and paper industry.
In order to identify any relevant, discrete subcategories of these seg-
ments of the industry, the following factors were considered:
1. Raw materials
2. Production processes
3. Products produced
4. Size and age of mills
5. Waste water characteristics and treatability
6. Geographical location
After analyzing these factors, it is concluded that the subcategorization
is defined as follows:
1. UNBLEACHED KRAFT means the production of pulp without bleaching
by a "full cook" process, utilizing a highly alkaline sodium hydroxide
and sodium sulfide cooking liquor. This pulp is used principally to
manufacture linerboard, the smooth facing of "corrugated boxes," but is
also utilized for other products such as grocery sacks.
2. SODIUM BASE NEUTRAL SULFITE SEMI-CHEMICAL (NSSC) means the pro-
duction of pulp without bleaching utilizing a neutral sulfite semi-
chemical cooking liquor having a sodium base. Mechanical fiherizing
follow8 the cooking stage, and the principal product made from this pulp
is the corrugating medium in the corrugated box "sandwich."
3. AMMONIA BASE NEUTRAL SULFITE SEMI-CHEMICAL (NSSC) means the pro-
duction of pulp without bleaching, using a neutral sulfite semi-chemical
cooking liquor having an ammonia base. Mechanical fiberizing follows the
cooking stage, and the pulp is used to manufacture essentially the same
products as is sodium base NSSC.
A. UNBLEACHED KRAFT — NSSC (Cross Recovery) means the production of
unbleached kraft and sodium base NSSC pulps wherein the spent NSSC liquor
is recovered, at least 75 percent of the operating time, within the un-
bleached kraft recovery process. The products made are the same as out-
lined above for the unbleached kraft and NSSC subcategories.
5. WASTE PAPERBOARD means the production of paperboard products from
a wide variety of waste papers such as corrugated boxes, box board, and
29
-------
newspapers without bleaching and without wood pulping. Small quantities
of virgin wood pulp may, in some cases, be admixed with the waste paper
furnish.
RATIONALE FOR SELECTION OF SUBCATEGORIES
Raw Material
Wood is the primary raw material of all pulping processes. While there
are differences in types of wood utilized, such differences have only
a minor impact upon waste water characteristics and treatability. For
example, a surveyed mill using southern pine had a raw waste loading
BOD5 of 14 kilograms per metric ton (28 pounds per Bhort ton) while a
similar surveyed mill using western pine had a raw waste loading BOD5
value of 15.5 kilograms per metric ton (31 pounds per short ton). This
difference is not significant in light of other data from 35 similar
mills using many different woods which had a typical range of 15 to 20
kilograms of BOD5 per metric ton (30 to 40 pounds of BOD5 per short ton)•
Raw materials used in the preparation of cooking liquors, however, differ
widely among pulping processes. The highly alkaline liquor used in
unbleached kraft produces waste water characteristics different from the
neutral NSSC liquors, for example. Sodium base NSSC utilizes neutral
sodium sulfite cooking liquor as described in Section III. This pro-
duces distinctly different waste water characteristics, as shown in
Section V, than the unbleached kraft process. Ammonia base NSSC utilizes
ammonia as a principal raw material in the preparation of cooking liquor.
This produces a waste water high In nitrogen, in contrast to other pulp-
ing wastes which are very low in nitrogen, as delineated in Section V.
Waste paperboard does not utilize wood as a raw material and therefore
no pulping chemicals are required. Its principal raw material Is waste
paper. Waste water characteristics from the manufacture of waste paper-
board differ widely from those which result from any of the pulping
processes.
Production Processes
All chemical pulping processes are similar in that each utilizes diges-
tion of wood chips with a chemical cooking liquor and removal of the
spent liquor from the cellulose pulp. Process differences among the
various pulp types relate primarily to the preparation, use, and recov-
ery of the cooking liquor. In the case of waste paperboard, no pulp-
ing is involved.
Pulp or waste paper furnish Is used to manufacture paper or paperboard
on papermaking equipment which has been described in Section III. The
papermaking operation Is similar for all products of the subject indus-
try segments.
30
-------
Thus, dissimilarities In production processes relate primarily to differ-
ences in raw materials utilized and end-products manufactured.
Products Produced
Section III discusses in considerable detail the vide variety of pro-
ducts produced by these segments of the industry and they are reviewed
briefly above. While the differences in characteristics and end-use of
the products are substantial, these differences do not of themselves
produce significant variations in waste water characteristics.
Age and Size of Mills
There is a substantial variation in age as well as size of mills in the
industry. Mills built over 40 years ago are still operating, as well as
mills built as recently as 1971. Most, if not all, of the older mills,
however, have been substantially upgraded and expanded so that most of
them are not "old" in the production sense. Waste water characteristics
from the "old" mills therefore do not show significant differences from
those of the "new" mills. For example, a surveyed "old" mill built in
1955 but expanded over several years through 1971, had 14 kilograms of
BOD5 per metric ton (28 pounds of BOD5 per short ton) of production in
the raw waste, whereas a "new" mill built in 1971 had an almost identi-
cal 14.5 kilograms of BOD5 per metric ton (29 pounds of BOD5 per ton). In
the case of ammonia base NSSC mills, age and size are not factors
since this is a relatively new process and only two mills are cur-
rently operating in the United States. One of these is scheduled for
shutdown in 1974.
Geographical Location
Waste water characteristics and treatability do not differ significantly
with geographical location, Irrespective of the raw materials and pro-
cess employed and the products produced. Climatic differences, however,
have an important effect upon treatability, and a lesser effect upon
waste water characteristics. This accounts for the inclusion of temper-
ature effects as an influencing factor in the standards.
31
-------
SECTION V
WATER USE AND WASTE CHARACTERIZATION
WOOD PREPARATION
Wood, the primary fiber raw material for unbleached kraft and NSSC
pulps, is received at the mills in various forms and consequently must
be handled in a number of different ways ( 2 ) . Some mills receive
chips from saw mills or barked logs which can be chipped directly. In
these instances, little, if any, water is employed in preparation of the
wood and no effluent is produced. Host mills receive roundwood in short
lengths with the bark remaining on it, and, since the bark interferes
with the pulping process and product quality, it must be removed.
Logs are frequently washed before dry or wet barking in order to remove
silt ( 15 ). In most installations a water shower is activated by the
log itself while on the conveyer so that a minimum of water is used.
The actual quantity discharged per unit of wood handled or pulp pro-
duced is most difficult to ascertain because of the wide weight varia-
tion in stick size and the fact that all the wood barked at some instal-
lations is not pulped, a portion going to lumber. However, the limited
data available indicate that this flowage amounts to about 380 to 1140
liters (1Q0 to 300 gallons) per cord of wood washed.
It is established that this effluent is very low in color and BOD (16 )
and that its suspended solids content is largely silt. Hence, it is
generally disposed of on the land together with grits and dregs from
the pulp mill and/or ashes from the boiler plants, or combined with the
general flowage to the treatment works. Effluent flowage and range of
losses from such operations are shown in Table 2.
TABLE 2
WOOD WASHING
Effluent Flow
100 to 300 Gal./Ton/Prod.
bod5
1 to 8 ///Ton/Prod
Total Suspended Solids
5 to 55 ///Ton/Prod.
Color
< 50 Units
33
-------
Most of the pulpwood used in the United States is small in diameter
and is barked dry in drums. However, when large diameter or long
wood is used, wet barking is commonly employed. The latter operation
is pretty much limited to northern mills and its use is presently de-
clining.
Wet barking of logs is accomplished by one of three methods: by drums,
pocket barkers, or hydraulic barkers (2)(17). Slabs are generally
handled by hydraulic units as is the larger diameter and long round-
wood.
The wet drum barker consists of a slotted drum equipped with internal
staves which knock the bark from the wood as the drum rotates in a pool
of water. The bark falls through the slots and is removed with the
overflow of water. These units handle from seven to 45 cords of wood
daily. Frequently the water supplied to them is spend process water
and recycling within the barking unit itself is often practiced. Bar-
kers of this type contribute from 7.5 to 10 kilograms of BOD (15 to 20
pounds) per metric ton of wood barked, and from 15 to 50 kilograms (30
to 100 pounds) per metric ton of suspended solids. Examples of the
BOD^ and suspended solids concentration of this waste water with the
barkers using fresh process water are shown in Table 3.
Wet pocket barkers are stationary machines which abrade bark from timber
by jostling and gradually rotating a confined wood stack against an end-
less chainbelt equipped with projections called "dogs" which raise the
wood pile allowing bark to pass between the chains. Water is sprayed
through apertures in the side of the pocket at rates of between 1254 and
2280 liters per minute (330 and 600 gpm) for pockets of 2.8 and 5.7
cords per hour, respectively. The use of this process is rapidly de-
clining in the United States.
Hydraulic barkers employ high-pressure water jets to blow the bark from
the timber which is either conveyed past them or rotated under a moving
jet which traverses the log. The volume of water employed is generally
from 19,000 to 45,600 liters (5000 to 12,000 gallons) per cord of wood
barked depending upon log diameter.
Water discharged from all three types of wet barking is generally com-
bined with log wash water, and then coarse screens are used to remove
the large pieces of bark and wood slivers which are conveyed away con-
tinuously. The flowage then passes to fine screens. These are of the
drum, fixed vertical, or horizontal vibrating type, having wire mesh or
perforated plate media with openings in the range of 0.127 to 0.254
centimeters (0.05 to 0.10 inches). Screenings are removed and mixed
with the coarse materials from the initial screenings, the mixture being
dewatered in a press prior to burning in the bark boiler. Press water,
which is combined with the fine screen effluent, is very minor in vol-
ume. The total waste flow, which amounts to about 19,000 to 26,600
liters (5000 to 7000 gallons) a cord, generally carries from 0.454 to
4.54 kilograms (one to 10 pounds) of BOD^ and 2.72 to 25 kilograms (six
to 55 pounds) of suspended solids per ton of product.
34
-------
TABLE 3
ANALYSIS OF WET DRUM BARKING EFFLUENTS
MILL
TOTAL SUSPENDED
SOLIDS
mg/1
NON-SET
SOLIDS
mg/1
% ASH
OF
S. S.
BODs
mg/1
COLOR
UNITS
1
2017
69
—
480
20
2
3171
57
21
605
50
3
2875
80
18
987
50
-------
The combined discharge contains bark fines and silt, the latter vary-
ing greatly in quantity since its presence is due mainly to soil adher-
ing to the logs. In dry weather the percentage of silt in relation to
bark fines is low as is the case when logs are stored in or transported
by water. However, attachment of mud in wet weather can make this
material a major percentage of the total suspended matter passing the
fine screens.
Fine screen effluent following hydraulic barkers has been analyzed by
several investigators (18 ) (19 ) (20 )} and examples are shown in
Table 4. It can be concluded from the data included in these publi-
cations that these effluents have a total suspended solids content
ranging from 521 to 2350 mg/1 with the ash content running from 11 to
27 percent. The latter is generally below 15 percent for clean logs.
BODc values range between 56 and 250 mg/1. These low values are due
to the fact that the contact of the water with the bark is short and
no grinding action on the wood takes place. Hence leaching of wood
and bark solubles are minimized. The water originally employed is all
fresh process water, since the close clearances of the high pressure
pumping systems supplying water to the jets will not tolerate the
presence of suspended solids in the water.
Such low values are not the case with drum and pocket grinding where
attrition in contact with water over an appreciable period of time
takes place. Also, spent pulping process waters already high in BOD
and color are not infrequently used for these barking processes which
raise further the ultimate level of organics in the screened effluent.
While wet drum and pocket barker fine screen discharge is not greatly
different from that of hydraulic barkers in suspended solids content,
the BOD5 can be considerably higher (16 )(18 ).
BOD values are also greatly affected by the specie of wood barked and
the season in which the wood was cut since wood juices and water ex-
tractables are responsible for it. That contributed by the suspended
matter present is a minor fraction of the total BOD. Curves presented
by Blosser (19 ), as shown in Figure 9, indicate that the 15-day
values are about twice those of the five day with little further demand
exerted after this period. Table 5 illustrates sewer losses from
wet barking operations, while Figure 10 shows' settleability character-
istics of barker screening effluent.
PULPING PROCESSES
Neutral Sulfite Semi-chemical
In most NSSC mills liquor is prepared by burning sulfur and absorbing it
in soda ash or ammonia, depending on base utilized. This part of the
36
-------
TABLE 4
ANALYSIS OF HYDRAULIC BARKING EFFLUENTS
MILL
TOTAL SUSPENDED
SOLIDS
mg/1
NON-SET
SOLIDS
mj»/l
% ASH
OF
S.S.
BODs
mg/1
COLOR
UNITS
1
2362
141
27
85
< 50
2
889
101
14
101
< 50
3
1391
180
17
64
< 50
4
550
66
11
99
< 50
5
521
53
13
121
< 50
6
2017
69
21
56
< 50
7
2000
<3 200
19
97
—
8
600
41
10
250
35
-------
FIGURE 9
LONG TERM BOD OF BARKER EFFLUENT
( AFTER FINE SCREENS)
RAW
FILTERED
10 15
DAYS INCUBATION
20
25
38
-------
J
TABLE 5
SEWER LOSSES FROM WET BARKING OPERATIONS
Mill # Eff. Flow BOD5 Total Susp. Solids
Thous. Gal./Ton Prod. #/Ton Prod. #/Tori Product
1 2.7 1.2 6.4
2 2.4 1.8 7.6
3 3.5 12.0 5.5
4 6.0 6.0 30.0
5 3.0 2.5 22.8
6 1.0 2.0 10.0
7 5.6 19.0 18.0
8 1.0 11.5 30.0
9 7.5 .20.1 34.0
39
-------
FIGURE 10 SETTLING RATE OF
BARKER SCREENING EFFLUENT
20 40 60 80
RETENTION TIME (MINUTES)
100
3240 1620 1000 810 646
CLARIFIER SURFACE LOADING-GAL./FT.2/DAY
40
-------
DRAFT
process produces only small quantities of liquid wastes other than
floor drainings, equipment wash-up, and cooling waters which can
frequently be used as process water.
Digester-relief and blow gases are condensed, and in some mills the
condensate is used for pulp washing. Pulp wash water together with
drainings from the blow tank are delivered to the recovery or liquor
burning system, or in the case of some sodium base mills to an adjunct
kraft recovery system.
From the washers the pulp is conveyed to an agitated chest where it is
diluted with white water from the paper mill to the desired consistency
for feed to the secondary refiners serving the papermaking operation.
Other than spent liquor, the pulping and washing operations discharge
little waste water since the small amount of residual liquor solids
present in pulp is carried through the machine system passing out with
the overflow white water (21 ).
The final effluent from NSSC mills is low in volume because of the high
degree of recycle commonly practiced in both the pulping and papermaking
operations. For the same reason it is high in BOD^. Without recovery
or incineration of the liquor, effluents would range from 1500 to
5000 mg/1 with a suspended solids content of from 400 to 600 mg/1. The
color and COD content would be correspondingly high (22 ). Overall
process losses in BODs and total suspended solids without recovery in
relation to pulp yield are shown in Figures 11 and 12.
Sodium base NSSC mills which practice extensive internal recycle and
other in-plant measures, as described in Section VII, have succeeded
in reducing raw waste pollutants to the lower levels shown in Table 6.
For example, Lowe (23 ) cites BOD5 loadings of 28.5 kilograms per metric
ton (57 pounds per short ton) at a flow of 7094 liters per metric ton
(1700 gallons per ton). As flow is progressively reduced through more
extensive in-plant measures, BOD^ is reduced to 14.5 kilograms per
metric ton (29 pounds per short ton) at 2921 liters per metric ton (700
gallons per ton). The lower value cannot be sustained, however, because
of operational problems outlined by Lowe ( 23 ) and in Section VII.
Similarly, Nelson et al. ( 24 ) reported short-term average of 5.5 kilo-
grams per metric ton (11 pounds per short ton) for BOD5. Again, oper-
ating difficulties are cited at this low level, and daily variations of
BOD range up to 25 kilograms per metric ton (50 pounds per short ton)
and higher. For the same mill, Nelson ( 24 ) reported a goal of about
50 kilograms per metric ton (100 pounds per short ton) of BOD^ after
installation of liquor recovery.
The effluent of a surveyed sodium-base NSSC mill utilizing recycle con-
tained 13 kilograms per metric ton (26 pounds per short ton) of BOD^
41
-------
FIGURE 11
BOD LOAD OF NSSC PULPING
(WITHOUT RECOVERY)
700
600
Z>
Q.
>
a:
o
UJ
u.
o
z
p
500
400
K
UJ
Q.
m
Q
g
cn
o
z
3
O
CL
300
200
100
RANGE
55 60 65 70 75 80
PERCENT PULP YIELD
42
-------
FIGURE 12 SUSPENDED SOLIDS LOSSES FROM NSSC PULPING
(WITHOUT RECOVERY)
120
no
Q.
>-
§
ID
CD 100
Z
e
\
(/>
Q
-J
O
(D
90
a
z
Ul
Q.
(/)
3
(/)
2
o
u.
o
O)
o
z
3
o
0.
80
70
\
\
\
\
\
\
\
\
\
\
\
\
\
\
\
PERCENT YIELD
43
-------
TABLE 6
NEUTRAL SULFITE CORRUGATING BOARDNILL EFFLUENT CHARACTERISTICS
(Mills with Liquor Recovery)
Mill it
Effluent Volume
Thous. Gal,/Ton
BOD,
#/Ton
T.S.S.
#/Ton
1
9.1
30
15
2
4.8
64
12
3
7.2
43
9
4
6.0
27
17
5
1.7
57
8
6
11.3
71
43
7
10.0
90
28
8
10.4
42
33
0
25.6
47
23
10
20.0
69
46
11
7.0
43
100
12
10.3
22
37
13
24.0
150
40
hb
-------
DRAFT
during the survey period lasting several days.
Total dissolved solids is frequently measured in the raw waste from
NSSC mills, since it is a relatively rapid indicator of upsets. As
dissolved solids exceed 1.5 percent due to increased recycle, Lowe( 23 )
reports increased operating problems. A surveyed sodium base mill re-
ported no operating problems due to total dissolved solids at the much
lower level of 0.2 percent. Nelson et al. ( 24 ) reported difficulties
in meeting wet strength requirements of the product when total dissolved
solids of the recirculated white water reached 3.7 percent.
An ammonia base NSSC mill has similar waste water characteristics, with
the exception of nitrogen. A surveyed mill had raw waste characteris-
tics of 16.5 kilograms per metric ton (33 pounds per short ton) of
suspended solids, 32.5 kilograms per metric ton (65 pounds per short ton)
of BOD^, and about 0.2 percent total dissolved solids. Kjeldahl nitro-
gen, however, reached a concentration of 220 mg/1 in this mill, whereas
sodium-base NSSC mills have a typically low nitrogen concentration of
only a few mg/1.
A process flow and materials diagram for a 250 ton per day NSSC corru-
gating board mill is shown in Figure 13.
Unbleached Kraft
The waste water resulting from unbleached kraft pulping comes primarily
from three areas of the process. The effluent from pulp washing, which
separates the spent liquor from the pulp, formerly consisted mainly of
decker filtrate water containing spent cooking liquor solids and ac-
counted for a high percentage of the total effluent. Today, the use of
hot stock washing, as discussed in Section VII, has considerably re-
duced the waste load generated in the washing operation.
Relationships between solids concentration of this waste water and BOD,.,
light absorbence, and conductivity are shown in Figure 14 ( 25 ). It
is obvious that the relationship of dissolved solids to the three other
parameters of waste strength is linear and of very similar slope. From
this it can be concluded that effluent strength as measured by these
parameters is a direct function of pulp washing efficiency and that con-
ductivity can be employed as an accurate monitoring index for the pulp
washing operation. The magnitude of this relationship can be disturbed
somewhat by loss of liquor to the vacuum system or to floor drains due
to foaming on the washers.
The second area of waste water sources is condensate streams. Relief
condensate from the digesters is condensed and the turpentine is
45
-------
Figure 13
COOLING
WATER
VACUUM
PUMPS
I
X
1
EVAPORATOR
CONDENSER
1.61 MG
1.10 MG
T
0.28 MG
r
PROCESS
HATER
AUXILIARY
EQUIPMENT
I
1
0.32 MG
0.66 MG
BOILERS
J
CHEMICAL
ASH
WOOD
DIGESTERS
BLOW
CHIPS
* *
TANK
200 CORDS
D.S. 200,500 §
LIQUOR
BURNING
D.S. 155,000 §
LIQUOR *
SCREEN
EVAPORATORS
CHEMICALS
BREAKER
REFINER
| D.S. 155,500
0.23 MG
WASHERS
WASTE PAPER
AND BROKE
BREAKER
BEATER
D.S. 55,000 I
i
REJECTS '
REFINER
0.40 MG
GRIT AND
STOCK
JUNK
CLEANING
REFINER
DECKER
PROCESS FLOW AMD MATERIALS DIAGRAM
FOR A 250 TON A DAY NSSC CORRUGATING
BOARO MILL
LEGENDS
D.S.- Dissolved Solids
MG - Million Gallons
STOCK
CHEST
NSSC PULP
STOCK
CHEST
50 Tons FIBER
PAPERBOARD
250 tors
SCREENS
i
i--
1
SURGE
TANK
~T
BLENDEO
STOCK
FILTER
D.S. 40,000 #
PAPER
MACHINE
SEWER
1.95 MG
46
-------
¦ts
111
o
z
U1
m
L_CC
. o
©m
_j <
o
w
to
2.0" 3,000' 1,000
1.6-
UJ
a e
f *
§ §
O X
o 2
FIGURE" 14
2500
1.2 ¦ 2P00-
0.8- Ij500
0.4-¦ 1,000
to
o
o
CQ
800 -
600 -
400 -
200
RELATIONSHIP BETWEEN TOTAL
SOLUBLE SOLIDS/ BOD, CONDUCTANCE
8 LIGHT ABSORPTION IN KRAFT
PULPING DECKER FILTRATE EFFLUENT
1.000
2p00
3000
4.000
TOTAL SOLUBLE SOLIDS, (mg/l)
-------
DRAFT
recovered from it by decantation. The residual water from this opera-
tion is sewered. Blow and evaporation condensates are contaminated
mainly with methanol, ethanol, and acetone, with'the extent of their
content a function of the wood species pulped ( 26 ). When surface con-
densers are employed on the evaporators, the volume of this stream is
low and its BOD^ can be reduced by air stripping in a cooling tower (27 )
or by stream .stripping ( 28 ). These condensates are frequently reused
for pulp washing.
All chemical recovery operations and other minor losses constitute the
last BOD,, source from kraft pulping.
Losses per ton of product from kraft pulping itself are difficult to
determine because of the common practice of reusing water from inte-
grated papermaking operations into the pulp mill ( 29 )•
A process flow and materials diagram for a 907 metric ton (1000 short
ton) a day draft linerboard mill is shown in Figure 15.
Total BOD5 raw waste load from unbleached kraft mills, including both
pulping and papermaking operations, is typically in the 15 to 20 kilo-
grams per metric ton (30 to 40 pounds per short ton) range. The sur-
veyed mills were in the lower region of this range, averaging 155
kilograms per metric ton (31 pounds per short ton). Suspended solids
data for 35 mills were within a typical range of 10 to 15 kilograms
per metric ton (20 to 30 pounds per short ton). Surveyed mills, how-
ever, averaged 18 kilograms per metric ton (36 pounds per short ton).
This difference is most probably explained by the fact that most mills
use a filter paper method of determining suspended solids, whereas
"Standard Methods"( 30 ) was used in the surveyed mills. The latter
test method generally yields higher results.
Raw waste color APHA units are typically in the 500-1500 range, and
one of the surveyed mills fell in the low end of this range at 567 units,
while a second surveyed mill, on a short term test, measured 286 color
units.
The impact of in-plant measures, as described in Section VIII, is evi-
dent in the surveyed mills as compared with previous typical ranges of
data. All of the surveyed mills had reduced their flows to the 40,173
to 54,249 liters per metric ton (10,000 to 13,000 gallons per short ton)
range. In contrast, an earlier report on 35 mills indicated a range of
83,460 to 125,190 liters per metric ton (20,000 to 30,000 gallons per
short ton). Haynes ( 29 ) reported in 1966 on 19 unbleached kraft
mills with a median water usage of 121,017 liters per metric ton
(29,000 gallons per short ton). The details of methods utilized to ac-
complish this flow reduction, with concommitant reductions in pollution
levels in the raw waste, are described in Section VII.
48
-------
WHITE LIQUOR
PURCHASED
CHIPS
r:
CHIPPERS
CHIP SCREENS
DRUM BARKERS
Wood 2190 Tons
546,000 Gal. Water 1
FINES
48 tons
BARK
BOILER
BARK
673 tons
WASH
WATER
'
r
SUMP
I
-X.
ROUND WOOD
1168 Cords
150,000 Gal.
SEWER
Cooling Water 208,200 Gal.
Wash Water
250,000 Gal.
NaOH
Sulfur
Water 1 ,000,000 Gal
DIGESTERS
BLOW TANKS
FIBERIZER
HOT STOCK
REFINER
Tons
TURPENTINE
STORAGE
TURPENTINE
DECANTER
J
OD
HOT STOCK
SCREENS
-tf
WASHERS
TALL OIL
SOAP
Turps. 14 Tons
Sulfur 1.4 Tons
Water 16,000 Gal.
CHEMICAL
MAKE-UP
SEWER
STRONG
BLACK LIQUOR
<&-
Sulfur 4.3 Tons
Water 2,000,000 Gal .
EVAPORATORS
NaOH
Sulfur
5.4 Tons
4.6 Tons
Na OH
Sulfur
33 Tons
'3 Tons
WEAK
BLACK LIQUOR
wi
HIGH DENSITY
STORAGE
B.L.
OXIDATION
SEWER
WHITE LIQUOR
STORAGE
Mud 500 Tons
NaOH 5.0 Tons
Sulfur 1.1 Tons
Water 76,000 Gal.
NaOH 135 Tons|
Water
RECOVERY
STACK
X
Di s.Org.1100 Tons
NaOH 600 Tons
Sulfur 50 Tons
Water 220,000 Gal.
Cooling Water
11 MGD
NaOH 600 Tons .
Sulfur 58 Tons
Dis.Org. 1150 Tons
Water 2,400,000 Gal.
RECOVERY
BOILER
DISSOLVING
TANK
1 ,200,000 Gal.
MUD WASHER
1
WHITE LIQUOR
CLARIFIER
NaOH 580 Tons
Sulfur 60 Tons
Inerts 10 Tons
CAUSTICIZER
CaO 140 Tons
Inerts 12 Tons
VENTURI
SCRUBBER
Water 10,000 Gal.
LIME KILN
LIME KILN
STACK
I
SLAKER
LIME
MAKE-UP
SAVE-ALL
~e=
MACHINE
CHEST
GREEN LIQUOR
CLARIFIER
I
LINERBOARD
1,000 Tons(OD)j
4-
DREGS
WASHER
GRITS
DREGS
BROKE
BEATER
r
-O-
PAPER MACHINE
CHEMICALS
Make-Up Water 403,400 Gal.
Figure 15
PROCESS FLOW AND MATERIALS DIAGRAM
FOR A I ,000 TON A DAY KRAFT
LINERBOARD MILL
Inerts 5 Tons
Water 24,100 Gal.
£
SEWER
Dis.Org. 11 Tons
Fiber & Add. 9 Tons
NaOH 4.5 Tons
Sulfur .46 Tons
Water 1,000,000 Gal.
-------
Waste Paperboard Mills
The raw waste load of waste paperboard mills is generated in the stock
preparation area and is mainly a function of the type of raw materials
and additives used. In general, the higher the percentage of kraft
or neutral sulfite waste paper used in the furnish, the higher the BOD
value per ton of product. Conversely, the higher the percentage of
waste newsprint of groundwood origin used in the furnish, the lower the
BOD^ per ton of product. Mills whose wastes have the higher BOD value
generally include those that employ an asphalt dispersion system in the
stock preparation process in order to melt and disperse the asphalt
found in corrugated waste paper. This system subjects the fiber to a
heat and pressure environment in a press and digester which contributes
to the higher BOD loads. A process flow and materials diagram of a
typical waste paperboard mill in shown in Figure 16.
Effluent volume, BOD^, and total suspended solids data for 42 mills
have been collected and are presented in Table 7. These were compiled
from data collected by the Michigan Water Resources Commission (31),
the Wisconsin Water Resources Commission (32), and the NCASI (33).
The volume of effluent ranged from 13,760 to 100,150 liters per metric
ton (3.3 to 24.0 thousand gallons per short ton) of product and it is
known that at three mills the effluent has been virtually eliminated
through clarification and water reuse. However, these mills manufac-
ture a small number of products of coarse grade which makes this pro-
cedure possible.
The minimum quantity of water required also depends on whether or not
food packaging grades of board are produced. If they are not, a re-
duction of discharge to the three to four thousand gallon per ton level
may be achieved. If they are, reuse is somewhat restricted since taste-
and odor-producing substances tend to accumulate in the system and ad-
versely affect the product. Slimicide usage is likewise limited since
some of these also impart odors. Hence, the minimum practical discharge
for a mill producing foodboard is generally considered to be about seven
to 10 thousand gallons per ton of product. Practically all products
can be produced in this effluent range.
Total suspended solids losses for the 42 mills listed range from 4.0 to
61.5 kilograms per metric ton (8 to 123 pounds per short ton) of product;
27 containing 20 kilograms per metric ton (40 pounds per short ton ) or
under. This value depends upon the type of save-all employed for fiber
recovery and the application of the more effective types is contingent
upon the kinds of waste paper used and the products manufactured. All
mills of this type can employ a cylinder-type save-all and, while it is
50
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BROKE 1
5 Tons j
TILLER
PULPER
0 574 MG
81 tons
'1°,
I
573 KG
CLEANING
SYSTEM
Z.014 HG
84 Tons
0 144 MG
79 Tons
REJECTS
1 ton
Sweetener Stock
J——
VAC. FILTER
Recovered Fiber
SAVE-ALL
1 44 MG
4 Tons
THICKENER
W W TANK
1 87 MG
5 Tens
0 713 MG
1 Ton
WHITE WATER
TANK
4-
BACK LINER
PIIIPCR
SELECT
UASTE PAPER
IfiiiL. 397 M' I , is]
iwteri y——
TOP LINER
W W TANK
TOP LINER
PULPER
BACK
LINER
0U*P
CHEST
0 086 HG
TOP LINER
DUMP
CHEST
HI-GRADE WASTE
PAPEP-VIRGIN PULP
BROKE
5 Tons
PAPER MACHINE
DRIER
SECTION
3 072HG
05Tons
PRESS
SECTION
PRODUCT
100 Tons
0 66 0 MG
1 0 Tons
0 072 MG
1 T°"
FORMING
SECTION
1 304 MG
2 Tons
0 713 KG
\ 0 Tons
0.843 MG-18 5 Tons
3 935 NG-84 Tons
0 693 MG-15 5 Tons
MACHINE SCREENS
O 069 MG
0 765 MG-1 5 Tons
3 316 MG- 6 Tons
0 636 MG-1 5 Tons
MACHINE PIT
O 108 MG
4 Tons
1.217 MG
3 Tons
7 O Tons |
! O 466 MG
^J'ons
TREATMENT
SYSTEM
O 144 MG 1
2-0 Tons J
y
1.325 MG
7 0 Tons
STOCK
CHEST
0 57 HG
80 Tons
0 101 IIG
18 Tons
BACK LINER
MACHINE CHEST
0 086 MG
15 Tons
0 574 MG
80 Tons
J1
FILLER m
MACHINE CHEST
Figure 16
PROCESS FLOW DIAGRAM AND MATERIALS
OF A
WASTE PAPERBOARD HILL
LEGEND
STOCK
PROCESS kATER
FRESH WATER
EXTENSIVE UATER RE-USE
-------
TABLE 7
WASTE PAPERBOARD MILL WASTE LOADINGS
Mill
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Eff. Vol.
bod5
T.S.S
M gal/ton
///ton
j/ 7tOP
11.0
36
122
16.3
42
123
8.5
15
87
14.3
22
98
4.0
16
8
10.8
13
20
21.6
14
40
10.0
16
42
20.0
36
28
9.7
20
33
9.5
18
28
10.0
19
18
9.5
75
67
6.7
12
14
15.0
67
106
12.4
23
42
10.3
24
59
3.3
32
21
11.5
12
21
5.8
18
34
15.8
16
27
12.5
42
76
9.3
22
30
5.8
16
18
13.4
10
21
12.7
24
30
7.5
35
33
19.2
29
40
6.6
46
29
16.6
16
65
13.0
36
40
11.4
22
43
6.0
17
68
9.5
14
32
10.0
25
16
10.4
20
14
8.6
12
14
24.0
25
54
10.0
25
70
10.4
20
16
8.6
12
14
12,5
26
18
52
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not the most effective type, it serves to separate usable from unusable
fiber and ordinarily restricts losses to less than 20 kilograms per
metric ton (40 pounds per short ton). It also serves to protect efflu-
ent treatment systems from slugs of fiber and clarifiers from flotation
problems.
BOD^ values ranged from 5 to 37.5 kilograms per metric ton (10 to 75
pounds per short ton) of product, 30 of the 42 being less than or equal
to 12.5 kilograms per metric ton (25 pounds per short ton). Over and
above that portion of the BOD imparted to the waste by fibrous organic
materials, residual pulping liquor, starch, and other adhesives, such as
glutens, account for mogt of it. Hence, there is no in-process control
that can be exercised over the BOD losses other than the reduction of sus-
pended solids. This accounts for the wide variation observed. Some hy-
drolysis of cellulose takes place during the process adding to the
dissolved BOD.
These wastes are generally substantially neutral though for some grades
of board lean toward the acid side due to the large amount of alum used
as sizing. They seldom, however, contain mineral acidity and can be
treated biologically without neutralization. They generally contain rel-
atively little true color unless such is imparted by the water supply,
but can be quite turbid due to the presence of clay or titanium dioxide
used in the process or entering the system with the waste paper. They
are not toxic, but can have a high bacteria count, these organisms being
largely Enterobacter aerogenes. Concentrations of suspended solids,
BOD , and COD are similar to those of strong sanitary sewage and they
respond well to the treatment methods applied to sewage.
PAPER MACHINES
The manufacture of paper involves two relatively discrete process systems
in terms of quantity and quality of water utilizations, namely the wet
end and the dry end of the machine. Refined pulp stock is discharged
to the machine chest from which it enters the wet end of the paper
machine. The stock is pumped to a headbox, or stuff box, which meters
the quantity of stock to the paper machine. Process water is added
to reduce the stock consistency to 0.25-0.5 percent either in the
headbox or the vat, depending on whether the forming section is a
cylinder or fourdrinier machine.
The stock deposits on a cylinder or fourdrinier wire and excess machine
white water passes through the wire. A large portion of this white
water is recycled back through the machine stock loop, and the excess is
pumped to a white water collection chest for reuse in the stock prepara-
tion area. Any remaining excess goes to a save-all for fiber collection
and white water clarification. These showers clean areas which tend to
develop fiber buildup and represent the largest portion of raw waste
53
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water generated by a paper machine.
The sheet is carried by cloth felts to the forming and press sections
where additional quantities of water are removed. Felt cleaning
showers which add more excess water are used. They are required, how-
ever, in order to maintain the drainability of the felt. The sheet
passes through the drier section to the dry end where water use is
generally low in volume and consists principally of cooling water.
If on-machine coating is practiced it involves a coating kitchen in
which the coating is made up to specifications and applied in successive
applications to the sheet. The presence of this operation generates
a low volume waste water relatively high in BOD^ and dissolved solids.
Many mills utilize a broke pulper on the dry end of this machine. This
represents the largest single water use in this area and is generally
recycled white water. However, this system component is responsible
for creating process water system imbalances of the greatest magnitude.
Since a dry end break requires that the entire tonnage of the machine
be reduced to pulp consistency the volume of water needed to accomplish
this is very high. The imbalance created depends on. the duration of
the break and generally is reflected by an increase of volume with an
attendant increase in suspended solids and, to a lesser extent, BOD,,
and dissolved solids in the mill effluent. During this period the
treatment facilities may be subject to two or three times the average
waste load generated by the mill. The subsequent impact on the per-
formance of the mill waste treatment facilities is not documented,
however. Since treatment capabilities are a function of time and pounds
of contaminant per unit of time, the impact must exert an influence
which is hidden in the 24-hour average waste load data reported by
the mill.
The impact of this system on a mill practicing near complete recycling
of process water is probably more critical. Normal operation requires
facilities for recycling process water within the machine loop and the
stock preparation loop, and from one loop to the other. To accommodate
a dry end or wet end break, the process water system must be capable of
responding quickly to the need for a large volume of process water at
either the wet end or dry end of the machine without utilizing fresh
water make-up. This system must also have the capacity to bring this
volume of water back into the process water system without losses to
the mill discharge sewer.
54
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SECTION VI
SELECTION OF POLLUTANT PARAMETERS
WASTE WATER PARAMETERS OF SIGNIFICANCE
A thorough analysis of the literature, mill records, sampling data which
has been derived from this study, and the Corps of Engineers permits
demonstrates that the following constituents represent pollutants accord-
ing to the Water Pollution Control Act for the subcategories under study:
BOD
suspended solids
PH
color
nltrogeh
RATIONALE FOR SELECTION OF IDENTIFIED PARAMETERS
Biochemical Oxygen Demand (5-day, 20*0
This parameter is a measure of the amount of biologically degradable or-
ganic matter which is present in the waste stream. Failure to substan-
tially reduce the amount of BOD5 in the waste stream before discharge to
receiving waters would adversely affect water quality by consuming large
amounts of dissolved oxygen. Although the amount of B0D5 per ton of
product In the discharge from an industrial process varies to a large
degree between subcategories, and even significantly from mill to mill
within a given subcategory, its treatability is essentially constant.
Measurement of BOD5 requires uniform procedures and trained personnel.
It is difficult to use as a control indicator of waste treatment per-
formance because of the five day test period which is required.
Suspended Solids
Pulp mill and waste paperboard operations contain appreciable organic
matter in solution. However, suspended solids can represent up to 30 per
cent of the total BOD5. Suspended solids are those solids which can be
removed from the waste stream by sedimentation in a quiescent zone, and
are usually determined In the laboratory by filtration. Coarse and
floating matter Is not included in an analysis of suspended solids. Re-
moval of suspended solids, including biological solids, substantially
reduces both the organic and inorganic pollutant load otherwise exis-
tent in the effluent from a mill.
E«
The effluent from a typical biological treatment process will normally
55
-------
have a pH In the range of 6.0 to 8.5, which is not detrimental to most
receiving waters. However, the application of some technologies for the
removal of color, solids, and nitrogen can result In major adjustments
in pH. The effluent limitations which are cited insure that these ad-
justments are compensated prior to final discharge of treated wastes in
order to avoid harmful effects within the receiving waters.
Color
Color is defined as either "true" or "apparent" color. In "Standard
Methods for the Examination of Water and Wastewater" (30), the true
color of water is defined as "the color of water from which the turbid-
ity has been removed." Apparent color Includes "not only the color due
to substances in solution, but also due to suspended matter." In the
various chemical pulping processes, lignin and lignln derivatives are
solubllized and removed from the wood during the cooking process. The
spent cooking liquors containing these highly colored compounds are
removed from the pulp in a washing sequence following the cooking pro-
cess. The wash water is highly colored, and large amounts of color are
ultimately discharged to the receiving stream despite some recovery
operations.
Nitrogen
Nitrogen is a nutrient which can cause excessive growth of algae and
other aquatic vegetation when discharged in significant quantities.
Pulp and papermaking waste flows normally contain only minor concen-
trations of this nutrient, and nitrogen compounds must often be added
to provide desired biological waste treatment efficiencies. As a result,
effluent limitations on nitrogen are not considered necessary, although
a monitoring program should be established to insure that nitrogen com-
pounds do not pass through the biological treatment process as a result
of excessive use. The one exception regarding limitations is for the
ammonia base NSSC subcategory. Large quantities of ammonia nitrogen
can be released to the waste water from the industrial process itself.
Failure to substantially reduce this pollutant could be highly detrimen-
tal to receiving waters.
OTHER PARAMETERS INDICATING PRESENCE OF POLLUTANTS
Both COD and TOC are indicators of the presence of pollutants and of the
efficiencies of the treatment and control technologies being applied.
Therefore, effluents from treatment facilities should be monitored for
each of these parameters. Both COD and TOC are a measure of organic and
some inorganic matter in the waste stream. As such, they are more Inclu-
sive than BOD5. Unfortunately, no consistent ratios have been establish-
ed within the pulp and paper industry between BOD5 and these other two
parameters. However, properly developed COD and TOC results can be an
effective control indicator of waste treatment performance since tests
can be completed rapidly and can be generally related to BOD5 within a
given mill.
56
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SECTION VII
CONTROL AND TREATMENT TECHNOLOGIES
SUMMARY
Waste waters discharged from the subject subcategories of the industry
to receiving waters can be reduced to required levels by conscientious
application of established ln-plant process loss control and water re-
cycle measures and by well designed and operational external treatment
facilities of established efficiency. Present technology will not
achieve zero discharge, except in a few cases where land availability
and soil conditions permit small mills to employ irrigation and seepage.
This section describes both the in-plant and external technologies which
are either presently available or under intensive development to achieve
various levels of pollutant reduction. External technology is used to
treat the residual waste concentration levels to achieve the final re-
duction of pollutant discharge to the receiving water bodies. In some
cases the "ln-plant" and "external" technologies merge. For example,
a mill may employ extensive suspended solids removal equipment intern-
ally, reusing both the clarified water for manufacture and the recovered
solids in the product, whereas another similar mill may depend to a
greater extent on "external" suspended solids removal to arrive at a
similar end point.
IN-PLANT MEASURES
Generally, mills which reduce raw waste pollutant loads concommitantly
reduce effluent flowage through recycle. An example selected from two
surveyed unbleached kraft mills will illustrate this point. The raw
waste load of one such mill contained 22.5 kilograms of BOD5 per metric
ton (45 pounds of BOD5 per short ton) of production using 58,422 liters
of water per metric ton (14,000 gallons of water per short ton). The
effluent of the second mill contained only 17 kilograms of BOD5 per
metric ton (34 pounds of BOD5 per short ton) at a 41,731 liter of water
per metric ton (10,000 gallons of water per short ton) flow.
All subject subcategories use similar stock preparation/paper machine
systems to manufacture the mill product. Since all such systems utilize
similar technology to control waste discharges, they are considered
together, and all such techniques apply to all subcategories except as
noted.
Large quantities of water are necessary to form a sheet of paper. Typi-
cally, the fibrous stock is diluted to about 0.5 percent consistency
before entering the paper machine itself. Such dilutions are necessary
57
-------
in order to provide uniformity of dispersion of the fibers in the sheet
of paper, as well as to provide other desired qualities such as smooth-
ness. Most of this water must be removed in the papermaking process,
since only a small amount of moisture, typically five to eight percent
by weight, is retained in the final sheet.
A high percentage of this water is removed in the forming section of the
machine. In the case of a fourdrinier machine, the water is removed
by rolls, called table rolls, or foils located under the endless-felt
screen or "wire" onto which the dilute stock is fed. Additional water
is removed by suction boxes and a suction couch roll which transfers
the sheet from the wire to the felt. In a cylinder machine, the water
drains through the screen-covered drums which are immersed in vats con-
taining the dilute stock.
After leaving the forming section of the machine, the sheet of paper or
board contains about 80 percent moisture. A press section employing
squeeze rolls, sometimes utilizing vacuum, is used to further reduce
moisture to a level of about AO percent. The remaining moisture is
removed by steam-heated drying rolls.
Water leaving the forming and press sections is called white water, and
approximates 104,325 liters per metric ton (25,000 gallons per short ton)
of paper or board. Due to recycling, only a relatively small portion
of the total Is wasted. Typically, in a mill utilizing extensive recy-
cle, only 2087 to 20,865 liters of white water per metric ton (500 to
5000 gallons of white water per short ton) is discharged from the system.
As shown in the process flow diagrams for each of the subcategories in
Section V, water is used in the manufacture of pulp and paper for a
variety of purposes including washing, cooling, transporting, chemical
preparation, gland seals, vacuum pump seals, felt washing, and washups.
In addition, water is a necessary material in the chemical-mechanical
process of "hydrating" or "brushing" pulp fibers during stock prepara-
tion in order to promote the bonding characteristics required to form a
sheet of paper or board.
These uses of water, and the technology available to reduce pollutant
loadB in the raw waste water, are discussed below.
Recycling of this white water within the stock preparation/papermaking
process has long been practiced in the industry, as discussed in Sec-
tion V. In the last 10 years, further strides in reuse have been made.
Problems associated with increased reuse usually manifest themselves in
reduced machine speed and/or product quality. Slime growth due to in-
crease of BOD and temperature have been encountered. This problem can
be reduced by the proper application of blocides, by better housekeep-
ing, and by design for higher liquor velocities in pipelines, shorter
detention times in tanks, and avoidance of pockets in the system. Scale
buildup is another problem which can be reduced, principally by chemical
58
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and mechanical design techniques. Buildup of dissolved solids can also
cause product quality problems, but in the typical case, reuse is lim-
ited by slime growth and scale buildup.
Most mills employ a save-all to recover fibrous and other suspended
material escaping from the paper machine. This is considered by many
mills to be a necessity for both economic and pollution control reasons,
although some mills can obtain equivalent results by other means. Save-
alls are of three principal types. First is the older drum type which
employs a rotating screen-covered drum immersed in a vat containing the
waste water. The water passes through the drum, leaving a mat of fiber
which is removed continuously for reuse. Second is the newer disc type,
which utilizes a series of screen-covered discs on a rotating shaft
immersed in the vat. The action is similar to the drum save-all, but
the disc type has the advantages of greater filtering area per unit
volume and the use of vacuum, both of which reduce space requirements.
In both of these types of save-alls a side-stream of "sweetener" fibrous
stock is added to the influent to improve the efficiency of suspended
solids removal in the main influent feed. The recovered fiber is then
removed from the save-all for reuse directly in the manufacturing
process. The third type is the dissolved air flotation save-all (DAF).
In this type unit air bubbles, formed on the addlton of air under pres-
sure, attach themselves to the fibers, causing them to float to the sur-
face, where a continuous mechanical rake recovers them for reuse.
The disc type has enjoyed recent popularity because of its flexibility
and higher removal efficiencies in most cases. In addition it pro-
vides a positive barrier for fibers preventing their introduction
into the clarified white water. DAF units are still pupular, however,
in waste paperboard mills.
Clarified effluent from save-alls is on the order of 10,433-25,038 liters
per metric ton (2500-6000 gallons per short ton) (15), with a suspended
solids content of 120 milligrams or less per liter (one pound or less
per 1000 gallons), whereas the influent may contain 2398 milligrams or
more per liter (20 pounds or more per 1000 gallons).
All or a part of the clarified effluent may be discharged directly to a
sewer, but most mills reuse a significant portion of the effluent for
such services as (15):
1. Vacuum pump seals 5. Pulp washing
2. Machine showers 6. Pulp mill recovery chemical
dilutions
3. Stock cleaner elutrlatlon
4. Cooling waters
7. Wash-ups
8. Consistency regulation dilution
59
-------
9. Barometric evaporator con- 10. Repulping of broke and pur-
denser 8 (pulp mill) chased fiber
Vacuum pumps are utilized In paper mills to provide a vacuum source to
accelerate the removal of water from fourdrlnler machines, presses,
save-alls, and other devices. Most such pumps are of the ring seal type,
which require large amounts of water. This water provides a seal be-
tween the moving parts of the pump, and is necessary to avoid backflow
of air to the vacuum side. Water used for this purpose approximates
10,433 to 16,692 liters per metric ton (2500 to 4000 gallons per short
ton). It must be sufficiently free of suspended solids to avoid plug-
ging of the orifices or other control devices used to meter it to the
pump. Further, it must not be corrosive to the mechanical parts of the
pump, and it must be relatively cool (typically less than 32°C (90°F))
to permit development of high vacuums of 0.67-0.74 atm. (20-22 in. Hg.)
For lower vacuum requirements 0.17-0.40 atm. (5-12 in. Hg.), somewhat
higher temperatures are permissible.
As more Intensive recycle is employed In machine systems, the signifi-
cance of this volume of seal water Increases. The use of mechanical
seals has reduced the volume of seal water, but they have so far not
proven satisfactory In many applications. Reduction of seal water usage
la an area which requires more Btudy and development.
Meantime several methods are used to minimize fresh water requirements,
depending on product as well as mill configuration. Seal water is
collected and passed through for reuse directly back to the pumps or to
another water-using system. The use of excess white water for vacuum
pump sealing, before discharge to sewer or back to process, Is also
practiced. Another procedure 1b to utilize the discharged vacuum pump
water for cooling of heat exchangers.
Seal water Is also used on packing glands of process pumps, agitators,
and other equipment employing rotating shafts. It cools bearings, and
lubricates the packing, and minimizes leakage of the process fluid.
Even though the amount of water used per packing is small — generally
in the range of 1.86 to 11.34 liters per minute (0.5 to 3 gpm) — the
total usage is quite extensive because of the large number of rotating
shafts required In the processes. The total usage may approximate 4173-
8346 liters per metric ton (1000-2000 gallons per short ton) of paper or
board. Methods used to control and reduce quantities required include
proper maintenance of packings and flow control of individual seal water
lines. In some cases, seal water which leaks from the packing can be
collected and reused, usually after filtering.
Water showers are used In both the forming and pressing sections to clean
the wire, felts, and other machine elements subject to contact with the
stock. Formerly, large volumes of fresh water were used for this pur-
pose. In recent years, attention has focused on the use of recycled
60
-------
white water on showers, and this trend has increased with the develop-
ment of self-cleaning showers. Even with self-cleaning showers, however,
a suspended solids content of less than 120 milligrams per liter (one
pound per thousand gallons) is generally desired to avoid plugging.
Concurrently, the use of high pressure (up to 52 atm. or 750 psig), low
volume showers using fresh water has Increased. These are employed
where product, operability, cleanliness, or other factors mitigate
against the use of white water showers. In many such cases, it is possi-
ble to operate these high pressure showers on a time cycle, so that flow
occurs only a small percentage, 10 to 20 percent, of the time.
Showers are also used on grooved presses to keep the grooves clean and
operable. Grooved presses were developed within the last 10 years and
have enjoyed increasing popularity because of their efficiency in water
removal, and lower capital and operating cost than the suction (i.e.,
vacuum) presses which they replace. Recycle of this shower water, usual-
ly after filtering to remove fibrous and other suspended solids, is
commonly employed.
Whether recycled water or lower volumes of fresh water are used for
showers, a reduction in fresh water usage and its concomitant waste
water flow results. Significantly, this reduction also decreases the
fiber losses to sewer.
Since the 1950's, free-discharge cleaners have been used increasingly to
remove dirt and other undesirable materials from the dilute stock prior
to its application to the paper machine. These cleaners are the cyclonic
type and operate on the centrifugal force principle, utilizing hydraulic
pressure drop as the source of energy. They increase cleaning effi-
ciency through a continuous discharge of rejects although significant
quantities of usable fiber are also rejected. To reduce such losses,
the cleaners are usually arranged in stages, to that the rejects from
previous stages are sent through subsequent stages of smaller size. Re-
jects from the last stage have a consistency of about three percent and
are usually sewered. Well designed and operated cleaner systems reject
one-half to one percent of production from the final stage. To reduce
such losses further, elutrlatlon water is added or In some cases, a
closed-discharge cleaner replaces the free-discharge unit in the final
stage. Either method reduces sewer losses.
Cooling water is used for bearings, particularly in older mills using
sleeve bearings instead of the anti-frlctlon bearings used in new or
rebuilt mills. Cooling water is not contaminated and can be collected
and reused either directly (after heat removal), or indirectly by dis-
charge into the fresh water system, if heat buildup is not a problem.
Similarly, water used to cool brake linings in paper rewind applications
may be reused. Water used to cool condensate from the steam dryers can
similarly be reused, but because of high heat loads cooling of this
water by cooling towers or other means would usually be necessary. None
of the mills surveyed in this study cooled this water. However, one
61
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mill surveyed returned dryer condensate directly to the feed water heat-
er at the boiler plant under 1.20-1.34 atra pressure (three-five psig
pressure), thereby reducing the cooling water requirement. This approach
could be used more generally where dryers are operated at pressures above
1.34 atm.(five psig).
While reduction of cooling water wastage does not, per se, reduce the
level of pollutants in the waste water, it does reduce the volume of
waste to be treated, thereby reducing the capital and, in some instances,
operating cost of waste treatment facilities.
Reuse areas numbered five through 10 may utilize save-all effluent as
make-up and are discussed in other sections of this report.
Unbleached Kraft
Barking of wood prior to pulping is most commonly performed by dry pro-
cesses which require very little water. This practice is preferred over
wet barking from the viewpoint of reducing raw waste load. Where wet
barking is employed, however, the B0D5 and suspended solids losses are
not a major percentage of the total waste, as pointed out in Section V.
Treatment consists of screening followed by settling to remove fine sus-
pended solids (principally silt). Heavy duty mechanically-raked clari-
fiers are preferably employed, with a design rise rate of 40,741-48,890
liters per square meter per day (1000-1200 gallons per square foot per
day) and a retention time of two hours ( 8 ). Clarified effluent may
be added to the mill biological treatment system. Settled solids are
removed continuously and are readily dewatered for disposal.
In dry drum barking which is employed by many linerboard mills, the
wood is sprayed with water on entering the drum to remove soil and
loose bark. From 0.83 to 1.67 liters per metric ton (0.2 to 0.4 gallons
per short ton) of product is used and in some instances the water is
settled and recycled. Overflow from settling ponds is discharged to
treatment systems.
Many linerboard mills receive wood in the form of chips either direct
from the forest or, more generally, from saw mills. In these cases, no
barking is required. As the forest products Industry continues its
trend toward maximum utilization of the tree, it is likely that more
wood will be delivered as chips and less round wood will be barked by
pulp mills, thus reducing or eliminating waste water discharges from
this source.
After cooking, pulp is washed to remove the dissolved wood substances
and spent cooking chemicals. Older practice was to dilute the pulp to
about one percent consistency after washing in order to promote effec-
tive screening for the removal of knots and shives. Thickening on a
decker was then required to raise the consistency for storage purposes.
62
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The water removed by the decker typically accounted for about one-third
of the total BOD5 loss from the mill.
Modern practice reduces this loss substantially by a process modification.
After cooking, the pulp is passed through a fibrilizer which fractionates
the knots remaining with the pulp. The pulp then passes through a spe- '
daily designed hot stock screen which effectively removes shives prior
to washing. This sequence avoids the need for dilution of the pulp for
screening after washing, so losses from this source are reduced. This
practice is preferred for unbleached kraft pulps from the waste water
viewpoint. Rejected knots and shives, if not recooked, are disposed of
on the land and are not permitted in the mill sewer system.
In the kraft recovery process, inert materials originating in the wood
and other raw materials must be removed. Inert grits from the lime-slak-
ing operation are generally removed for disposal on the land as are dregs
from the white and green liquor clarification steps. This practice reduces
the suspended solids loss to the sewer.
Condensates from the recovery system evaporators and from condensed blow
tank vapors account for about one-third of the total BOD5. Table 8 ( 34 )
shows typical reuse points for these condensates. Methanol accounts for
about 80 percent of their organic content and for most of the BOD5 ( 35 ).
Other alcohols, ketones, and small quantities of phenolic substances,
sulfur compounds, and terpenes account for the remainder. Because of
the odorous compounds, reuse of condensates has been restricted by air
pollution considerations. This led, about 10 years ago, to the develop-
ment of technology to remove such compounds. Steam stripping of conden-
sates has been studied extensively for this purpose (36)(37)(34), but
no application has been made as yet on unbleached kraft mills in the
United States. It should be pointed out that from the cost viewpoint
some mills may find it advantageous to discharge untreated condensates
to their biological treatment systems which will effectively treat the
organic compounds.
A rule of thumb sometimes used in the industry is that one-third to one-
half of the BOD5 suspended solids in the raw waste are due to spills,
overflows, and wash-ups which occur when the production process is not in
equilibrium. These losses occur due to a variety of factors including
breakdown of equipment, routine maintenance, planned shutdowns and
startups, power failures, and grade changes. For economic reasons,
efforts are made to minimize these occurrences, but even under the best
of circumstances, they occur regularly and therefore should be taken in-
to consideration in any waste management program.
An example occurred during a survey of one mill which experienced an un-
usual short-term black liquor loss. This caused raw waste BOD5 to in-
crease from 17 to 29 kilograms per metric ton (34 to 58 pounds per short
ton). Suspended solids increased from 11 to 18.5 kilograms per metric
ton (22 to 29 pounds per short ton). Such shock loads can Interfere
63
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TABLE 8
REUSE OF EFFLUENT FROM DIFFERENT UNIT OPERATIONS
Type of Effluent gal/ton
Place of Reuse
Blow gas conden-
sate, direct
Blow gas conden-
sate, Indirect
1500-5900
Average:
about 2000
350-400
Cooling-water for 1500-5900
blow-gas condenser, Average:
indirect about 2000
Turpentine-
decanter
10-165
Average:
50
1. Brown stock washing
2. Screen room or decker operation
3. Hot water supply
4. Mud washing
5. Dissolving of additives
1. None (Sewered)
1. Hot water supply
2. Brown stock washing
3. Bleached stock washing
4. Screen room or decker operation
1. Showers on knotter
2. Showers on brown-stock washers
Cooling water for
turpentine conden-
ser
650-2400 1. Hot water supply
2. Screen room
3. Boiler make-up water
4. Direct blow-heat condenser
Evaporator
condensate
Evaporator
barometric
effluent
Cooling water for
evaporator surface
condensers
675-2800
Average:
about
1500-2000
8000-15000
1. Brown stock washing
2. Lime kiln scrubber
3. Cooking liquor preparation
4. Mud-washing or dreg washing
5. Woodyard
6. Wash-ups
7. Sewer
8. Boiler make-up water
1. Transport of barc-boiler fly ash
2. Recycled through cooling-tower
1. Hot water supply
2. Machine showers in paper mill
Evaporator seal
pit, discharge
from surface
condensers
400-1550
1. Brown stock washing
64
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with external treatment operation, reducing its removal efficiency.
Short-term biological processes are particularly susceptible to upset
from shock loads.
The following practices should be employed to eliminate or minimize
non-equilibrium losses:
1. Evaporators should be periodically "boiled out" to remove
scale and other substances which interfere with efficient
operation. A storage tank should be provided to contain
the flushed material, which can then be slowly returned
to the process when it is again in operation.
2. Storage facilities should be provided for weak black liquor,
strong black liquor, and recovery plant chemicals and li-
quors. These should be adequately sized to avoid overflows
In approximately 90 percent of process upsets. Provision
can be made to return these stored materials to the origi-
nating subprocess at a later time.
3. Production curtailments should be made as required to
avoid overflows which cannot be otherwise prevented, if
such overflows would cause treatment plant upset or in-
creased discharge of pollutants. Sewer segregation can be
utilized, especially in new mills, to minimize these im-
pacts, in conjunction with-adequate storage.
4. Continuous monitoring within mill sewers (especially conduc-
tivity) should be employed to give immediate warning of un-
known spills so that corrective action can be promptly taken.
5. Personnel should be trained to avoid such spills where
possible, and to take immediate corrective action when
they occur.
6. Storage lagoons located prior to biological treatment may
be provided to accept longer term shock loads. The con-
tents can then be gradually returned to process or to
treatment without detriment to treatment operations or to
receiving waters.
Sodium Base Neutral Sulfite Semi-Chemical
Water reuse and upset control in this subcategory of mills have been
described in detail in the literature ( 24 ) ( 21 ) ( 38 ) • The practices of
one tightly closed NSSC mill (i.e., with maximum reuse) are illustrative
of possible internal modifications to maximize reuse and upset control (24).
The principal direct uses of water in this operation which consists of
an NSSC pulp mill and a closely integrated paper mill are identified as:
65
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1. Chip cooking
2. Certain fourdrinier showers
3. Pump shaft seals
Indirect uses of fresh water Include:
1. Vacuum pump seal coater
2. Losses from indirect steam heating
3. Cooling and condensing systems
Excess white water is used, without treatment, for dilution injection in
the digesters and in the screw presses used for separation of strong
cooking liquor prior to evaporation and burning.
During dally wood pulp production of 181.4 metric tons (200 short tons),
some 90,800 kilograms (200,000 pounds) of dissolved solids are produced.
Seventy five percent of this amount is removed in the combined screw
pressate and digester blow liquors, reduced to 21 percent solids by
indirect evaporation, and supplied to the fluldlzed bed reactor. Addi-
tional solubles are introduced into the overall system via the 86.2 me-
tric tons (95 short tons) of waste paper utilized dally.
The remaining soluble solids remain with the pulp as it proceeds to the
stock preparation/papermaking system. Routinely a high percentage of
these solubles remains with the paperboard as manufactured, but two
principal sewer losses occur. One Is "carryover" into the vacuum pump
seal water. The other represents non-equilibrium losses due to shut-
downs, equipment failures, and other factors mentioned in the above sub-
section on unbleached kraft mills.
Emphasis is placed on controlling the effects of these non-equilibrium
upsets. These efforts include:
1. Prevention of spills by process control modifications.
2. Redirection of overflow pipes to trenches leading to "con-
taminated" surge vessels for ultimate reuse.
3. Individual revisions of level controls and storage tanks to
minimize overflows and spills.
4. Redundant installation of key pumps and other equipment to
avoid losses due to equipment failure and routine mainte-
nance .
5. Monitoring systems to alert operating personnel of potential
and actual spills so that corrective action can be promptly
Initiated.
66
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It will be recognized that most of these techniques are the sane in
principle, if not in detail, to those in-plant measures applicable to
unbleached kraft mills.
From the engineering viewpoint, it is readily evident that none of
the above measures represent novel technology. What is novel, however,
is the "systems approach" to a complex manufacturing operation having
variables and potential loss points measured in the hundreds or even
thousands. This kind of effort, however, is necessary and recommended
to effect a significant reduction in raw waste loads — particularly
surge loads — with their adverse Impact upon external treatment facili-
ties and final effluent quality.
The beneficial effect of such a program can be illustrated by the follow-
ing "before" and "after" raw waste data ( 24 ):
Before Extension After Extension
Parameter Reuse Reuse
APHA0 Color Units 600 275
B0D5 1187 56
Conductivity (meromhas) 4300 500
With these and further improvements funded partially by EPA, this mill
is now in a position to install a reverse osmosis system to handle
unavoidable final spills (39). For this system to operate economically
it Is Imperative to reduce the volume of waste water to be treated.
While this program will not result In zero discharge of pollutants, it
is expected that very significant reductions, over and above those
itemized above, will occur.
Another mill (21) has applied similar techniques In reuse of white
water, but has taken a different approach in disposal of spent NSSC
liquor. As In the above case, Intensive reuse results in white water
characteristics approaching those of the spent liquor itself. For ex-
ample, white water solubles approach the three to four percent figure in
both mills. Since both mills make corrugating medium, the corresponding
levels of solubles (primarily spent cooking liquor) can be tolerated in
the end product. This is not true of many other subcategory grades.
Problems occur with increased reuse as discussed in the subsection above.
An NSSC mill (21) has delineated these problems as process water usage
approached 6260 liters per metric ton (1500 gallons per short ton):
1. Variable paper quality due to wet streaks In wet felts
2. Decreased wet felt life due to plugging from fines
67
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3. Increased slime deposits
4. Higher maintenance costs due to Increased cleaning of
machine elements
5. Higher corrosion rates
6. Increased calcium scaling
7. Greater chemical demands for sized and wet strength grades
8. Buildup of contaminants from waste paper
9. Increased Incidence of sheet breaks, particularly at the
presses, due to "stickiness" caused by solubles buildup
and to apparent reduction in wet web strength
To minimize the above problems, fresh water usage was increased to 8346
liters per metric ton (2000 gallons per short ton) from 6260 liters per
metric ton (1500 gallons per short ton).
Ammonia Base Neutral Sulfite Semi-Chemical
Ammonia base and sodium base NSSC pulping are separate subcategories in
that the two bases produce different waste characteristics. However,
they are essentially the same process in terms of equipment used and the
manufacturing steps involved, with the exception of spent liquor hand-
ling in some cases. Therefore, the sources of waste water would gener-
ally vary only as they typically vary from mill to mill without a sub-
category, and thus, -offer a potential for water reuse similar to that
described above for sodium base mills. Ammonia base mills, however,
have experienced somewhat more difficulty in reduction of waste flow
volume through reuse because of the buildup of ammonia within the pro-
cess system.
The techniques and methods for reducing upset and spills described for
both the kraft and sodium base NSSC mills, or some modification of them,
are equally applicable to this subcategory.
In the newest mill of this type — there are only two in operation —
design efforts are underway to eliminate a waste stream which contributes
about 18-20 percent of the total raw BOD5 load of the mill. This is
from the screwfeeder utilized to press water from the chips before the
digester to achieve a sufficiently high dry solids content.
The additional Internal control needed in this type of mill Is one which
will reduce ammonia concentrations in the waste stream. One proposal 1b
to channel the primary cooling water into the weak black liquor as it
68
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enters the evaporators (40), thus lowering the pH and inhibiting con-
version of ammonium to ammonia.
Waste Paperboard
The raw waste load discharged by waste paperboard mills is a matter sub-
ject to some interpretation since the tendency to treat waste water for
reuse prior to biological treatment has become typical in the Industry.
This practice Involves either the use of internal treatment or an extern-
al plant primary clarifier for the removal of suspended solids from the
process white water prior to water reuse on the wet end of the paper
machine and other selected areas in the mill. The recovered solids are
recycled for reuse in the stock system in both cases. The excess water
not returned to the mill for reuse represents the waste volume discharge
to external biological treatment or to municipal waste treatment facili-
ties.
Mills which practice only nominal reuse of process water or provide
primary biological and secondary solids removal facilities generate a
primary clarifier effluent waste load that equates to the raw waste load
of the mills practicing extensive reuse. In order to compare the raw
waste load of mills using any one of the three different systems, it
appears that the primary clarifier effluent of each is the most equita-
ble parameter. That this is the most representative raw waste load for
a mill is supported by the industry-vide practice of recycling all pri-
mary clarifier sludge back to the process. Under these conditions the
clarifier influent does not represent the actual waste load leaving the
process.
The use of this criterion for defining raw waste loads for mills
becomes more significant when considering the fourth response to
pollution abatement in this subcategory — i.e., almost total recycle
of treated waste water. This requires the recycle of process water to
the extent that the fresh water used for process purposes nearly equals
the evaporation rate from the process system. In addition to small
steady-state discharges, the waste water generated by these mills is
mostly the result of intermittent discharges from holding basins used
to contain the many variable flows associated with production require-
ments. These Include excessive stock dumps, grade changes, and mill
wash-ups, as discussed in Section VII.
Achievement of recycle is made by differing routes. One approach utilizes
a well-designed ln-plant treatment facility with safeguards designed into
the system to accommodate process variations and upsets. Another utilizes
the outer plant primary clarifier effluent with surge storage tanks and
screening equipment on the water return to the mill to Insure reliability
of the quality of the recycle water.
There are a few mills in this subcategory, built within the last ten
69
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years, in which the concept of nearly complete process water recycle was
designed into the process at the engineering stage. This approach
utilizes one or the other of the two solids removal systems described
above. It also Includes extensive non-contact cooling water collection
and recycled fresh water systems used in non-contaminating areas and
discharged separately to the environment without treatment . In addition,
It utilizes deslgned-in selective process water use and recycle prac-
tices.
One such mill was surveyed during this study in order to obtain reliable
information regarding the waste loads generated in the process water
systems and the final effluent. This mill did not employ biological
treatment systems on the final discharge. The waste loads discharged to
the environment were significantly lower in terms of gallons per day,
pounds per ton, and pounds per day than discharges from mills with secon-
dary settling and biological treatment facilities. The BOD5 discharged
by mills with secondary treatment facilities averaged 0.25 kilograms
per metric ton (0.5 pounds per short ton); the mill without biological
treatment, but with near complete recycle, achieved 0.075 kilograms
per metric ton of BOD5 (0.15 pounds per ton). The waste loads of the
latter mill were also far lower than achieved by the other mills In
total suspended solids and total dissolved solids — i.e., 0.075 and 0.5
kilograms per metric ton (0.15 and 1.0 pounds per ton) respectively ver-
sus an average of 0.75 and 12.5 kilograms per metric ton (1.5 and 25.0
pounds per short ton). However, the concentrations of these pollutants
were considerably higher in the final discharge to the environment. Al-
so, the concentrations of dissolved solids attributable to the exten-
sive recycled process water system reached significantly high levels
which this particular production process was able to tolerate.
Evaluation of the results obtained by the four basic approaches to the
pollution control effort of this subcategory supports the fact that
the waste waters generated respond well to the biological treatment pro-
cess for the reduction of suspended solids, BOD5, and, to a lesser
extent, except with near complete recycle, dissolved solids. The waste
Is generally deficient in phosphorus and nitrogen making the addition of
these nutrients necessary to achieve good biological treatment perform-
ance. The waste is generally low In heavy metals concentration, rarely
exceeding one milligram per liter, and typically at or below the test
concentration limits.
Historically, the raw waste water for mills in this subcategory has been
characterized in terms of a particular manufacturing process and by the
raw materials used in the process. The realization of near complete
reuse of process water by some mills Indicates that this factor becomes
paramount when characterizing the waste loads discharged to the environ-
ment on an industry wide basis. In order to compare the results achieved
by the various systems described above it becomes necessary to reduce
the pollutant-measuring parameter to pounds per day and then to pounds
per ton of product. This criterion provides a more accurate measure of
70
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pollutant load and a more valid basis for comparison than can be obtained
using concentrations of pollutant.
Based on the data cited above, this study shows that very extensive re-
use of process water produces a significantly reduced final waste load
than is achieved by mills practicing moderate to fairly extensive reuse
of process water plus biological treatment.
71
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EXTERNAL TREATMENT TECHNOLOGY
Waste treatment requirements do not vary appreciably within or among the
five subcategories studied. Although there are variations in concentra-
tions and specific waste constituents, the general classes of compounds
which can be expected to occur in their wastes derive from the pulping
of virgin wood fiber or repulping of waste fiber and are, thus, charac-
teristic of them all. These substances are dissolved organic components
of wood such as lignins, tannins, sugar, and cellulose degradation pro-
ducts. They make up the bulk of the oxygen demanding waste of these
subcategories.
Other compounds such as adhesives, sizing material, starches, and resin-
ates are used in making many paper and paperboard grades. Depending on
product use, other additives may be employed. The residual of all of
these substances in the waste load, or combinations of them, can be treat-
ed with the same group of technologies.
Kraft and NSSC pulping employ chemicals with a resulting Increase in
chemical waste constituents. However, chemical recovery in kraft mills,
recovery or liquor incinceration in sodium base NSSC mills, or cross
recovery between the two drastically limit chemical discharge. Waste
paper is flberized by hydraulic and mechanical means so there is no
comparable chemical use or discharge from waste paperboard mills.
Removal of Suspended Solids
The physical process of removing suspended organic and inorganic mate-
rials, commonly termed primary treatment, is accomplished either by
sedimentation or flotation, or a combination thereof. Screening ahead
of treatment units is particularly useful for barking and wood washing
effluents and is necessary in all cases to remove trash materials which
could seriously damage or clog succeeding equipment. Automatically
cleaned screens, operating in response to level control, are commonly
employed and represent preferred practice.
Primary treatment can be accomplished In mechanical clarlfiers, flota-
tion units, or sedimentation lagoons. Although the latter enjoyed wide-
spread use in the past, the large land requirement, coupled with
Inefficient performance and high cost for cleaning, has made them less
popular in recent years (8).
Dissolved air flotation has been applied to effluents from waste paper-
board mills and has achieved removal efficiencies of up to 98 percent of
the suspended solids (41). The relatively high cost of flotation
equipment, its requirements for flocculating chemicals, high power re-
quirements, and its mechanical complexity make it unsuitable for appli-
cation in other than the capacity of a save-all, except where space is
at a premium. Also, its capacity to handle high concentrations and
shock loads of solids is somewhat limited.
72
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The most widely used method for sedimentation of pulp and paper wastes
Is the mechanically-cleaned quiescent sedimentation basin (8). Large
circular tanks of concrete construction are normally utilized with ro-
tating sludge scraper mechanisms mounted in the center. Effluent
usually enters the tank through a well which is located on a center
pier. Settled sludge is raked to a center sump or concentric hopper and
is conveyed to further concentration or disposal by solids handling
pumps. Floating material is collected by a surface skimmer attached to
the rotating mechanism and discharged to a hopper.
At kraft and NSSC mills, clarlfier diameters range from 9.14 to 106.68
meters (30 to 350 feet) and overflow rates from 15,970 to 82,702 liters
per square meter per day (392 to 2030 gallons per square foot per day)
overflow. A design overflow rate of 24,444-28,518 liters per square
meter per day (600-700 gallons per square foot per day) and a detention
time of four hours with a solids loading of 20.49-81.94 square meters per
metric ton (200-800 square feet per short ton) of dry solids per dav is
recommended (42). More conservative design, however, is in the 12,200-
20,400 liters per square meter per day (300-500 gallons per square
foot per day) range. A survey of 12 mills in the five subcategories
indicates that the majority of the plants have primary clarlflers with
overflow rates ranging from approximately 8148-28,518 liters per square
meter per day (200-700 gallons per square foot per day). The role of
the clarlfier in the effluent treatment system of an NSSC mill Is
illustrated in Figure 17.
A properly designed and installed mechanical clarlfier is capable of
removing over 95 percent of the settleable suspended solids from all
the effluents produced by the subcategories studied. The removal
efficiency of this fraction of the total suspended solids is the true
measure of performance for this device since it cannot be expected to
separate those solids which will not settle under the most favorable
conditions. The settleable solids content of linerboard mill effluents
average 85 percent of the total suspended solids.
Because of the biodegradable nature of a portion of the settleable
solids present In the effluents of these mills, clarification results
in some BOD reduction. However, this reduction is lower for these
subcategories than for some other segments of the industry since pulp
mill and waste paperboard operations contain appreciable organic matter
in solution. Tabulated data for a number of mills showed a BOD5 reduc-
tion effected by settling is less than 20 percent for linerboard mills
and less than 30 percent for waste paperboard mills.
BOD Reduction
BOD reduction is generally accomplished by biological means, again be-
cause of the relative biodegradability of most of the organic substances
In the waste • Lignin is the one major exception. Advances in reduction
73
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BAR
SCREENS
MILL
EFFLUENT
LAND
DISPOSAL
FIGURE 17
EFFLUENT TREATMENT AT NEUTRAL SULFITE
SEMI-CHEMICAL CORRUGATING BOARD MILLS
THAT INCINERATE SPENT COOKING LIQUOR
CLARIFIER
I
I
I
i
SLUDGE
DEWATERING
AERATED
BASIN
SETTLING
BASINS
OUTFALL
FLOW METER
C>
'
-------
of internal chemical losses and recycling have removed most of the toxic
factors which interfere with biological activity.
While BOD reduction by biological methods represents common practice to-
day, it should be understood that other methods discussed under "Color
Removal" and "Advanced Waste Treatment" may, in the future, avoid the
need for biological treatment to reduce BOD.
Common current biological treatment practice Is the use of very large
storage oxidation basins, aerated stabilization basins, or to a lesser
extent, the activated sludge process and modifications thereof. The
storage oxidation basin is the most widely used method in kraft pulping,
followed closely by the aerated stabilization basin (34). The activated
sludge process is used by only nine kraft mills, and a trickling filter
is presently being employed by two kraft mills for pretreatment (3A).
A process flow diagram of linerboard effluent treatment is shown in
Figure 18.
Since the oxidation basin is a relatively low-rate process, large land
areas are required, making it unsuitable for many locations. Because of
the availability of land, and the warmer climate which helps to maintain
consistent biological activity, most natural oxidation basins are found
in the southern states (8). Ninety percent BOD removal efficiency for
an 82-day detention time stabilization basin treating unbleached kraft
waste Is reported (34). Design loading rates of 56 kilograms BOD per
hectare per day (50 pounds BOD per acre per day) for natural oxidation
basins to achieve 85-90 percent removal in warm climates were also
reported (43). A survey of four mills with loadings of 59.4 kilograms
BOD per hectare per day (53 pounds BOD per acre per day) or less showed
BOD removals ranging from 80-93 percent, while basins averaging 112-336
kilograms BOD per hectare per day (100-300 pounds BOD per acre per day)
had removals in the 23-55 percent range. For shallow basins an oxygena-
tion rate of 67.3 kilograms BOD per hectare per day (60 pounds BOD per
acre per day) is used for design purposes.
By Installing aeration equipment in a natural basin, Its ability to
assimilate BOD per unit of surface area Is greatly Increased. The
aerated stabilization basin, as used by all subcategories, originally
evolved out of the necessity of increasing performance of existing natu-
ral basins due to increasing effluent flows and/or more stringent water
quality standards. It soon became apparent that the process had many
applications in the pulp and paper industry and, as a consequence, sig-
nificant use of this waste treatment process began in the early to mid-
sixties.
Due to its Inherent acceleration of the biological process, the aerated
stabilization basin requires much less land than the natural stabiliza-
tion basin and because of the long reaction period less nutrient addition
than that required for activated sludge. Typically, 0.21 hectares per
million liters (two acres per MGD) of the aerated stabilization basin
75
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STRONG WASTE
HOLDING BASIN
CLEAN
COOLING WATER
LOW SUSP.SOLIDS
.EFFLUENTS
DIVERSION
CHAMBER
DISCHARGE
REG.BASIN
HIGH SUSP.SOLIDS
EFFLUENTS
SPILLAGE &
WASH-OUTS
IN-STREAM
DIFFUSER
FLOW METER
BAR
SCREENS
ASH
BASIN
WOOD YARD
RUN OFF
WOOD
WASHINGS
INORGANIC
WASTES
FIGURE 18
METERING
PUMP
COLLf
WE
XTION
ILL
DECANTATION
EFFLUENTS
1 f
FROM SLUDGE
HANDLING
SETTLING
BASINS
PROCESS FLOW DIAGRAM
LINERBOARD MILL EFFLUENT TREATMENT
CLARIFIERS
nnr
ALTERNATE
SETTLING
BASINS
STORAGE
OXIDATION
ALTERNATE
AERATED
OXIDATION
ALTERNATE
SECONDARY
CLARIFIER
AERATION
TANKS
1.
TO SLUDGE
CONDITIONING
AND DISPOSAL
1
I
I
WASTE
ACT. SLUDGE
t
RETURN ACTIVATED SLUDGE
-------
compared with 4.8 hectares per million liters (40 acres per MGD) for
natural basins for equivalent treatment levels (34 ). Detention times
in the aerated stabilization basin normally range from five to 15 days,
averaging less than 10 days. Of the 12 mills studied in these cate-
gories, nine mills employed aerated stabilization basins, most with less
than 10 days detention time.
Due to the relatively long aeration time, the buildup of sludge solids
is considerably less than for higher rate processes, particularly where
primary clarification is employed. Typical rates are 45.4 to 90.8 grams
(0.1 to 0.2 pounds) of sludge generated for each 454 grams (pound) of
BOD removed (8). The sludge is removed as formed by endogenous respira-
tion, sludge loss in the effluent, and sedimentation within the aeration
basin. However, discharge of untreated waste to an aerated stabiliza-
tion basin without prior clarification can result in a buildup of sludge
which after a period of time will impede its efficiency. An unbleached
kraft mill in the study group reported a significant loss in operating
efficiency after a period of eight years, at which time approximately
25 percent of the aerated lagoon was filled with sludge. Dredging of
the sludge returned the process to a high operating efficiency.
Most mill wastes are deficient in nitrogen and phosphorus. Many of the
mills studied found it necessary to add these nutrients to the aeration
basin. Nitrogen, in particular, is added in almost every case by mills
in four of the subcategories. Reported optimum ratios of BOD to nitro-
gen are 50:1 with four days aeration, and 100:1 with 10-15 days aeration
(43). The exception is, of course, the effluent of ammonia base NSSC
mills which is high in nitrogen as discussed in Section V.
Aeration is normally accomplished using either gear driven turbine-type
aerators, direct-drive axial flow-pump aerators, and, in a few cases,
diffused aerators. Oxygenation efficiencies under actual operating con-
ditions range from 0.61 to 1.52 kilograms of oxygen per kilowatt per
hour (one to 2.5 pounds of oxygen per horsepower per hour), depending
on the type of equipment used, the amount of aeration power per unit
lagoon volume, basin configuration, and the biological characteristics
of the system. A dissolved oxygen level of 0.5 mg/1 remaining in the
lagoon liquid is required to sustain aerobic conditions (44). Design
experience indicates that 1.1 to 1.3 kilograms of oxygen per kilogram
BOD5 (1.1 to 1.3 pounds oxygen per pound B0Ds)are required to maintain
adequate DO for waste oxidation and endogenous respiration at the bio-
logical mass produced.
Although the activated sludge process has been employed for many years
to treat domestic sewage, it was first applied to pulp and paper mill
waste in 1953 (43). The process is similar to the aerated stabilization
basin except that It is much faster, usually designed for four to eight
hours of total detention time. The biological mass grown in the aera-
tion tank are settled in a secondary clarlfler and returned to the
aeration tank, building up a large concentration of active biological
77
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material. Since there is approximately 2000-4000 mg/1 of active sludge
mass in the aeration section of this process, as opposed to 50-200 mg/1
in the aerated stabilization basin, dissolved and suspended organic mat-
ter are removed much more rapidly, greatly reducing necessary tank vol-
ume as well as required detention time. Since biological organisms are
in continuous circulation througout the process, complete mixing and
suspension of solids in the aeration basin is required. The active
microbial mass consists mainly of bacteria, protozoa, rotifers, fungi,
and cyntomnemotodes. Because the process involves Intimate contact of
organic waste with biological organisms, followed by sedimentation, a
high degree of BOD and solids removals are obtained.
The contact stabilization process Is a variation of activated sludge
wherein two aeration steps are utilized rather than one. First, the
Incoming waste is contacted for a short period with active organisms
prior to sedimentation. Settled solids are then aerated for a longer
period to complete waste assimilation. Contact stabilization has been
applied successfully to integrated kraft mill effluent, while conven-
tional activated sludge is used at most other mills.
Activated sludge plants treating pulp and paper waste have been loaded
up to 2.41 kilograms of BOD5 per cubic meter (150 pounds of BOD5 per
1000 cubic feet) of aeration tank volume per day (8). Of the 12 mills
studied two utilized activated sludge treatment with primary and
secondary clarification. In both cases, tank loadings were less
than 0.80 kilograms of BOD5 per cubic meter (50 pounds of BOD5 per 1000
cubic feet) with one system operating at less than 0.24 kilograms of
BOD5 per cubic meter (15 pounds of BOD5 per 1000 cubic feet). Detention
times ranging from 2.5 to 8.5 hours with loading rates ranging from 601
to 2084 kilograms of BOD5 per cubic meter (37.5 to 130 pounds of BOD5
per 1000 cubic feet) have been reported (43). In all cases nitrogen and
phosphorus were added. A loading of 41 to 144 grams of BOD5 per day per
kilogram of mixed liquor suspended solids (0.2 to 0.7 pounds of BOD5 per
day per pound) for optimum sedimentation in the secondary clari-
fier was suggested.
The secondary clarifier performs the function of sedimentation of the
active microbial mass for return to the aeration tank. Rates of about
211 liters per day per square meter (600 gallons per day per square foot)
have been suggested ( 34). For a more conservative approach, secondary
clarifier rise rate should not exceed 141 liters per day per square meter
(400 gallons per day per square foot)(8). It is advisable to design
secondary clarifiers for lower loading rates as periodic episodes of
sludge bulking or poor sedimentation arising from variable loading and
aeration can occur.
Due to the fact that the sludge volume is greatly reduced in the acti-
vated sludge system, the endogenous respiration of the sludge mass is
considerably lessened. Thus, there are additional quantities of excess
sludge, one kilogram of excess sludge per kilogram of BOD (one pound of
78
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excess sludge per pound of BOD), which must be disposed of.
As in the case of the aerated stabilization basin, aeration can be
accomplished by mechanical or diffused aeration. The more efficient and
more easily maintained mechanical method is preferred by the pulp and
paper industry. Oxygen requirements where activated sludge processes
are utilized are in the range of one kilogram of oxygen per kilogram of
BOD5 (one pound of oxygen per pound of BOD5) removed.
Short detention times and low volumes make the activated sludge process
more susceptible to upset due to shock loads. When the process is dis-
rupted, several days are usually required to return the biological
activity and high BOD removal rates back to normal. Thus, particular
attention is required to avoid such shock loads in mills utilizing this
process. The greater shock load tolerance of aerated stabilization
basins, lower nutrient requirements, reduced sludge handling problems,
and lower cost, explains the general preference for this type of treat-
ment. Exceptions occur particularly where the high cost or unavaila-
bility of land dictates the use of the activated sludge porcess with its
much lower land requirement. One such use is in waste paperboard mills
located in urban areas. An effluent treatment flow diagram appears in
Figure 19.
Trickling filter usage in all subcategories is very limited, primarily
due to the inability of such systems to accomplish high degrees of BOD
removal at high loading levels (43). A kraft mill employing trickling
filters with artificial plastic media achieved 50 percent reduction of
BOD with 50 percent recycle at a loading rate of 80.16 kilograms of
BOD5 per cubic meter of media per day (500 pounds of BOD5 per 100 cubic
feet of media per day) (43).
SLUDGE DEWATERING AND DISPOSAL
Due to their high organic content, the dewaterlng and disposal of sludges
resulting from the treatment of kraft linerboard, NSSC corrugating board,
and waste paperboard mill effluent can pose a major problem and cost more
than the treatment Itself. In early practice, these sludges were placed
in holding basins from which free water from natural compaction and rain-
fall was decanted. When a baBin was full, it was abandoned, or, if
sufficient drying took place, the cake was excavated and dumped on waste
land. In this case, the basin was returned to service.
Odor problems from drying, as well as land limitations, have demanded the
adoption of more advanced practices. These are covered in detail in NCASI
Technical Bulletin No. 190 (42) and are described briefly below.
In the case of many waste paperboard mills which discharge into public
sewerage systems, effluent treatment sludges are handled with those con-
tributed by sanitary sewage. Methods are set forth in FWPCA Manual of
79
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00
o
MILL
EFFLUENT
CLARIFIER
BAR
SCREENS
WASTE
SLUDGE
FIGURE 19
EFFLUENT TREATMENT AT
WASTE PAPERBOARD MILLS
RETURN ACTIVATED SLUDGE
ALTERNATE
AERATION
TANK
SECONDARY
CLARIFIER
AERATED
BASIN
OUTFALL
LAND
DISPOSAL
SETTLING
BASINS
-------
Practice No. 20(45) and their effects on the overall process are de-
scribed in the literature (46).
Depending on the performance of devatering equipment, in some cases it
is either necessary or desirable to prethicken sludges. This is accom-
plished by gravity thickeners of the "picket-fence" type or by providing
a high level of sludge storage capacity in mechanical clarifiers. Small
mills sometimes employ high conical tanks which serve as both storage
tanks and thickeners. These have side wall slopes in excess of 60° but
contain no mechanism.
Sludges from waste paperboard mills can generally be thickened to a con-
sistency in excess of four percent dry solids by prethickening. If
activated sludge from secondary treatment is included, this figure can
be somewhat lower. Prethickening is generally not necessary for un-
bleached kraft sludges.
Vacuum filters are in common use for dewatering sludges from the pulping
and papermaking processes considered in this report. They produce cakes
ranging from 20 to 30 percent solids. Filtration rate ranges observed
for each subcategory are as follows:
Vacuum Filtration Rates of Sludges
Product Drv Kr/M2/Ht Drv 0/ ft2 Air
Unbleached Kraft 39 to 93 8 to 19
Waste Paperboard 10 to 29 2 to 6
Corrugated Board 10 to 64 2 to 13
Observed capacities for the poorly filterable sludges can generally be
about doubled by chemical conditioning with ferric chloride, alum, or
polyelectrolytes at a cost of from $2.72 to $4.54 per metric ton ($3.00
to $5.00 per short ton) of dry solids. Such treatment Is generally
necessary when activated sludge is included in the sludge to be dewatered
since the addition of 20 percent of this material on a dry solids basis
can reduce filtration rates as much as 50 percent.
Complete vacuum filter installations, including all accessories, range
from $4306 to $5382 per square meter of filter area ($400 to $500 per
square foot of filter area). Although a number of different types of
filters are in service, coil or belt types are the most popular among
recent installations. At one mill using coil filters, average cake
content of 23 percent was reported, with an influent sludge concentration
of 3.3 percent. Loading rates averaged 27.37 kilograms solids per square
meter of filter area per day (5.6 pounds solids per square foot of filter
81
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area per day). After initial problems, filter availability exceeded
96 percent and cleaning problems were minor (47).
In practice, the higher the consistency of the feed, the more effective
centrifuges are in terms of solids capture in relation to through-put
as well as to reduced cake moisture. Moisture is generally lower than
in cakes produced by vacuum filters. Cakes range from 25 to 35 percent
dry solids content and are in a pelletized easily handleable form. To
operate effectively, centrifuges must capture in excess of 85 percent of
the solids in the feed stream.
Centrifuges cost from $106 to $159 per liter per minute ($400 to $600
per gpm) of feed capacity. At a two percent solids feed consistency,
this is equivalent to 97.6 kilograms of dry solids (215 pounds of
dry solids) daily at 90 percent capture.
The application of drying beds for dewatering sludges is limited to small
mills and they are not constructed as elaborately as are those employed
for sanitary sewage. They generally consist only of multiple beds of
gravel or cinders without a complex underdrain system.
Detailed experiments on this method of dewatering waste paperboard mill
sludge set forth parameters of good practice and area requirements (48).
The latter vary naturally with the climate, although adjustments as to
the depth of sludge deposited and its initial moisture content are also
involved. The most effective depth is less than one foot.
Sludge can be removed for disposal on the land as soon as it becomes
"spadeable" or handleable with earth moving equipment. For paperboard
mill sludges, this condition is reached at about 25 percent solids con-
tent. Further drying occurs upon the land if initial drying is suffi-
cient.
Some sludges, including those from llnerboard mills, can be dewatered to
a solids content approaching 40 percent by pressing (49). . "V"-type
presses are most commonly used but others have proven suitable. First
efforts to employ presses involved the handling of sludge cakes obtained
from vacuum filtration which contained on the order of 20 percent solids.
Recent efforts have been toward direct use of presses on thickened liner-
board sludge, thus eliminating the first dewatering step.
Generally, pressing is followed by incineration in air-entrained incine-
rators which can bum the pressed sludge without supplemental fuel since
little further drying is required (50). Semi-chemical corrugating board
operations and waste paperboard mills of normal size, however, do not
supply enough sludge to support the operation of even a small Incinerator.
Future developments may permit incineration of sludges from such opera-
tions in existing fossil fuel-fired power boilers.
Sludge is also incinerated at some llnerboard mills in boilers burning
82
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bark or hog fuel. In this case, the pressed sludge is mixed with the
bark or fuel before Introduction into the furnace (42).
Both types of operation are described by Aspitarte et al. (50) and cost
figures are presented. The cost of air-entrained Incineration was
$14.33 per metric ton ($13 per short ton) and that for burning with hog
fuel was $12.68 per metric ton ($11.5 per short ton) of dry solids.
These figures agree with those presented by Coogan and Stovall (51),
Bishop and Drewl (52), and others.
Since most of the linerboard mills are large and located on large sites
not proximate to habitation, land disposal of sludge has been the most
common method employed. In many cases, basins have been utilized and
abandoned when they became full. Since water decanted from such basins
has a high BOD resulting from the degradation of cellulose, it is neces-
sary to return it to the treatment system. With time, the BOD5 in the
decanted waters becomes quite elevated, greatly increasing treatment
costs (47).
The sludge dewatering and disposal operation is illustrated in Figure 20.
Byproduct Usage
Interest has been stimulated in utilizing sludge from kraft mills in low
grade products such as roofing felts, but lack of uniformity mitigates
against such practice. Aspitarte (50) et al. experimented with the use of
this material as an organic soil supplement and with hydromulching.
Incorporation of high sludge levels into soil, after standing for a year,
increased bean and corn crops for two successive plantings as compared to
control crops. However, equivalent amounts of sludge added to the soil
each year caused reduction in crop yields which was apparently due to
nitrogen unavailability. In the hydromulching tests which sludge
was applied to a simulated highway cut, sludge with or without the
addition of bark dust was found to be competitive with a commercial
product for establishing a grass stand.
Interest in production of bacterial protein from celluloslc sludges
continues to attract the attention of researchers despite the failure
to date of similar products to gain a foothold in the market in this
country. A satisfactory product has been produced by growing thermo-
monospora fusca, a strongly cellulolytlc thermophylic organism on low
lignln pulp mill fines (53). This process is attractive in that acid
hydrolysis of the cellulose prior to fermentation is not required. The
observed substantial reduction of organic matter which is attained is of
considerable Interest.
83
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SLUDGE FROM
TREATMENT PLANT
WASTE SLUDGE
METER
GRAVITY
THICKENER
STACK
(OFF-GASES)
FILTERS
ALTERNATE
INCINERATOR
CENTRIFUGES
ALTERNATE
ALTERNATE
DISPOSAL AREA
DRYING BEDS
FILTRATES TO
TREATMENT PLANT
SLUDGE DEWATERING AND DISPOSAL
FIGURE 20
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IRRIGATION AND LAND DISPOSAL OF EFFLUENTS
Total mill effluentB of pulp and paper mills, as well as specific ones
having particularly undesirable properties, have been disposed of by
means of irrigation and land disposal. Examples of specific effluents
handled in this manner are cooking liquors, foul condensates, and turpen-
tine decanter water.
The advantage of land disposal, when properly practiced, is that a very
high degree of purification is obtained on passage through the soil so
that the water finally reaching either the adjacent stream or ground
water is practically devoid of suspended matter, BOD, and color. The
disadvantages are 1) the relatively small volume that can be disposed of
per acre per day,37,850 to 113,550 liters (10,000 to 30,000 gallons)
under most soil conditions, and 2) freezing problems during the winter
months. In some instances, this process is applied only during the cri-
tical months when temperatures are high, stream flowages low, and crops,
which Increase the allowable application rate appreciably, can be grown.
The use of land for the disposal of pulp and paper mill effluents has
been applied in the following forms:
1. Seepage ponds
2. Direct application to fallow soil with a wide range of textures
by both spray and ridge-and-furrow distribution
3. Application by similar means to soils whose absorption capacity
has been modified by development of suitable cover vegetation
4. Controlled effluent application designed to produce crops by
use of suitable irrigation practices.
Since these effluents contain little in the way of the basic fertilizer
elements, any value they add to the soil other than their irrigating
effect is the increased water-holding capacity and friability induced by
the stable organic matter present. The use of land disposal and irriga-
tion for disposing of these wastes has been described in detail by
Gellman (54). An assessment of the effectiveness of Irrigation on crop
growth and the parameters for application of water, BOD, cellulose, and
sodium for soils of different character and textures are set forth.
Kraft Linerboard Mill Applications
Although considerable demonstration work has been done on the use of
kraft mill effluents for irrigating fodder crops, com, vegetables, and
pine trees, there are at present no linerboard mills making large scale
use of this means of disposal. Detailed studies of the effects of kraft
mill effluents on the soil and its productivity have been published by
85
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Vercher, et al.(55) which Indicate the suitability of such effluents
for irrigation. However, after applications and trials made to date,
this technique has received only minimal acceptance by these mills on a
full scale (8).
The major problem is the large volume of effluent produced due to the
high production capacity of the mills now operating and the correspond-
ingly large land areas needed. For example, at an application rate of
8,346 liters per metric ton (20,000 gallons per short ton) of product,
2025 hectares (5000 acres) of land would be required for a 970 metric
tons per day (1000 short tons per day) linerboard operation. With large
land areas, transporting the effluent incurs both extensive capital and
operating costs, exceeding those for the common types of waste treat-
ment. This procedure would also necessitate the mill engaging in a busi-
ness sideline unless there was a neighboring agricultural operation to
contract for the waste water. The possibility of spraying the effluent
in woodlands to enhance tree growth has been explored but appears unat-
tractive both from the standpoint of its cost and the value received in
terms of increased wood yield.
At the present time only one unbleached kraft mill uses land disposal to
any extent. It employs seepage ponds seasonally following secondary
treatment of the effluent. The major purpose of this is to prevent
direct discharge of the treated effluent to the receiving stream during
the summer months.
NSSC Corrugating Board Mills
Land disposal of both spent cooking liquor and wash and machine waters
from NSSC mills has been described by Voights (56) and others. Such
disposal was at one time practiced by a number of mills, although only
two continue the practice today. This is primarily due to the increas-
ing popularity of cooking liquor disposal by pyroprocesses and treating the
remaining waste streams by the treatment methods common to the industry.
Thus, only the two most successful of the land disposal systems remain
in operation, one of which uses land disposal for spent cooking liquor,
and the other employs seepage drains for the entire effluent.
Waste Paperboard Mills
There has been no use of irrigation for the disposal of waste paperboard
mill effluents. Two mills, both located on small streams have, however,
irrigated fields growing fodder crops during the summer months with
treated effluent. This procedure proved very effective for one mill
because of its small size and correspondingly small land area require-
ment.
86
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COLOR REMOVAL
For more than twenty years, the pulp and paper industry has been activer
ly engaged in research for the reduction of color, primarily in kraft
mill effluents. These efforts have been directed particularly to those
cases where color discharge has created aesthetic problems due to the
high clarity of the particular receiving waters. The bulk of the re-
search has concentrated on development of lime precipitation techniques
because of the relative economics of this compared to other techniques,
and the familiarity with and availability of lime handling systems in
kraft mills. The overriding initial problem with the lime approaches
was the generation of large volumes of gelatinous, difficult to dewater
sludges. Several schemes were developed to overcome this problem and
full-scale systems have been installed in recent years. Color removal
efficiencies of 85 to 90 percent are being achieved. In two unbleached
kraft mills, the lime sludge is recovered, dewatered, and incinerated
in the lime kiln.
Considerable research has been performed on other color removal tech-
niques, principally activated carbon, reverse osmosis, and slum preci-
pitation. Alum precipitation was found to be economical in one instance
where alum mud from the nearby manufacture of alum is the primary
chemical source. A full-scale installation of this system is planned.
Activated carbon and reverse osmosis have been considered as polishing
treatment in conjunction with other processes, for producing a highly
treated effluent for discharge. Additionally, they have been considered
as a treatment process producing an effluent suitable for recycling.
The latter concept appears promising. However, full-scale testing has
not been tried to date.
Sources of Color
In the various chemical pulping processes, llgnin and lignin derivatives
are solubillzed and removed from the wood during the cooking process.
The spent cooking liquors, containing these highly colored compounds,
are removed from the pulp in a washing sequence following the cooking
process. The wash water is highly colored. In the kraft process,
however, this wash water is sent to the recovery area where the cooking
chemicals are recovered and the organic materials are burned in the
recovery furance. The washing and recovery operations are efficient;
however, losses of cooking liquor and the discharge of evaporator con-
densate result in a reddish brown effluent. Additionally, most un-
bleached kraft mills discharge the water removed from the pulp on the
last operation before going to the paper mill known as the unbleached
stock decker. The discharge from this operation is the most significant
colored effluent from the production of unbleached kraft pulp. Average
values of color discharged from kraft and NSSC pulping and from un-
bleached kraft papermaklng operations are shown in Tables 9 and 10 (34).
87
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TABLE 9
VALUES FOR COLOR DISCHARGED FROM VARIOUS PULPING PROCESSES (3)
Pounds of Color Units*
Effluent Per Ton of Product
Kraft Pulping 50 to 300
Kraft Papermaking 3 to 8
* Pound of color units (AP11A color Units) x 10"*^ x 8.34
TABLE 10
UNIT PROCESS FLOW AND COLOR DISTRIBUTION
IN INDIVIDUAL KRAFT PULPING EFFLUENTS (3)
Flow Thous. Gal/Ton Color Units
Paper Mill 11.4 10
Pulp Mill 0.9 520
Evaporators 0.1 3760
Recovery 0.2 20
88
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Lime Treatment
The development of the lime color reduction process has been traced by
several authors (57)(58)(34)(8), A brief review of this history is in
order. In the early 1950's, Moggio reported the results of a laboratory
program in which several coagulants were tested for their effectiveness
in reducing the color of kraft pulping and bleaching effluents (59). This
investigation measured the effectiveness of alum, ferric sulfate, lime,
sulfuric acid, char, clay, activated carbon, activated silica, ferric
chloride, chlorinated copperas, phosphoric acid, waste pickle liquor,
and a barium alumina silicate compound. In general, Moggio found that
good color reduction could be obtained with several of the agents. It
was concluded, however, that the cost of chemical treatment was prohib-
itive with the exception of lime treatment which afforded the possi-
bility of lime recovery In the normal mill process. In addition to the
prohibitive costs of chemical treatment, a large volume of difficult
to dewater gelatinous sludge formed in the chemical treatment processes
was cited as a major problem.
Based on the results of this early work, research continued towards
development of the lime precipitation process. The overriding problem
in this work continued to be the difficulty of dewaterlng the lime-
organic sludge. Specific studies were conducted for resolving the
sludge problem with limited success (60)(61). In an Investigation of the
surface reaction process (62(63)(64), In which effluent was filtered
through a precoat of hydrated lime, it was successful in the laboratory.
However, operational problems with the pilot plant scale system forced
this process to be abandoned.
Continuing efforts to Improve the dewaterlng of the lime sludge led to
consideration of using large dosages of lime for color reduction. It
was believed that a large quantity of rapidly draining material would
reduce the effect of the organic matter on dewaterlng. This thinking
led to the development and patenting of the "massive lime" process by
the National Council for Steam Improvement (65). In this process, the
mill's total process line is slaked and reacted with a highly colored
effluent stream. The line sludge is then settled, dewatered, and used
for caustlcizing green liquor. During the causticizing process, the
color bodies are dissolved in the white liquor and eventually burned in
the recovery furnace. A flow diagram of the patented process is shown
in Figure 21.
Although the massive lime process had been demonstrated as an effective
color removal system, the process was not taken beyond the pilot stage
for several years. The first large scale application of the process
was at the Sprlnghill, Louisiana mill of International Paper (66). This
plant was operated from February, 1970 to August, 1971. The results of
this operation are presented in a later section.
The massive lime process, as developed, relied on high concentrations of
lime (on the order of 20,000 mg/1). Because of this, only a relatively
small effluent stream could be treated with the quantity of lime used
89
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LIME
STORAGE
KILN
LIME
MAKE-UP
C02
LIME RECLAIMER
SLAKER
DECOLORIZED
EFFLUENT
BLEACHERY EFFLUENT
CLARIFIER
UNDERFLOW
FILTRATE
LIME MUD
TO KILN
GREEN LIQUOR
WHITE LIQUOR
CLARIFIER
MUD
WASHER
CAUSTICIZING
VACUUM
FILTER
MASSIVE LIME PROCESS FOR COLOR REMOVAL (5)
FIGURE 21
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OR/* T
for causticizlng green liquor. Additionally, the use of this process
required modifications to the recovery system. These restrictions and
the need for color removal from total unbleached kraft mill effluents
led to the Independent development of three lime precipitation pro-
cesses employing a "minimum" lime dosage for decolorization followed by
various methods of sludge disposal or recovery. Two of these systems
are now in full-scale operation on the total mill effluent from the
production of unbleached kraft pulp at Interstate Paper Co., in Riceboro,
Georgia and Continental Can Company in Hodge, Louisiana ( 67 )( 68 ). The
Hodge mill also produces NSSC. Lime dosages at both mills are about
1000 mg/1. At the Interstate mill, the lime sludge is not recovered.
Continental Can, however, dewaters the lime sludge by centrifuge and
recovers the lime in the process lime kiln.
Other Color Removal Systems
Although lime treatment methods have been the only color removal pro-
cesses installed on a full scale basis to date, research is ongoing for
other processes. These include activated carbon, reverse osmosis and
other membrane techniques, resin separation, ion exchange, and other
coagulation systems.
Activated Carbon
Timpe and Lang ( 34 ) have reported on the use of activated carbon in
combination with other treatment processes on a pilot scale for the
treatment of unbleached kraft mill effluent. The treatment sequences
were:
1. Primary clarification; activated carbon
2. Lime treatment; clarification; activated carbon
3. Clarification; biological oxidation; activated carbon
The flow diagram of the pilot system is shown in Figure 22. Two carbon
systems were evaluated. The first used four standard down-flow columns
for series or parallel operation. The second system is called the
FACET (Fine Activated Carbon Effluent Treatment) system and is a multi-
stage countercurrent, agitated system with continuous countercurrent
transfer of both carbon and liquor from stage to stage. It uses a
carbon size between standard granular and powdered classifications.
The system is the subject of a patent application.
In the lime-carbon system, lime dosages were from 318 to 980 mg/1 CaO,
and is referred to by the authors as "micro" lime treatment as compared
to the "minimum" lime treatment used by others, ( 66 )( 67 )( 68). With
these dosages, the authors state that recarbonation of the effluent is
unnecessary for reuse of the treated effluent. It should be noted that
the Intent of this investigation was to treat the effluent to a degree
allowing reuse in the mill. In this respect they were not necessarily
91
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ume-3, n r
CO
LIME TREATER
CARBONATOR pH
ADJUST-
MENT
FILTER ACT1VATEO CARBON COLUMNS
ACTIVATED CARBON
CLARIFICATION
No. 2 MILL EQUIU3RATION OR
EFFLUENT BIO-OXIDATION BASIN
SPENT
CARBON
FACET
CONTACTORS
FILTER
STORAGE
TANK
FIGURE 22 - EFFLUENT TREATMENT PILOT PLANT
-------
Do &
KM:-' a
looking for a combination of systems capable of producing an effluent
suitable for discharge.
Smith and Berger ( 69 ) investigated the efficiency of activated carbon
absorption preceded by massive lime treatment, carbonation, and extended
aeration in a batch treatment pilot plant. This process was also
evaluated without the extended aeration step.
Thibodeaux and Berger (70) made similar studies on a pilot scale. They
investigated the effects of massive lime treatment, biological oxida-
tion, and absorption in granular carbon columns. McGlasson, et al.(71)
investigated the effect of activated carbon as a polishing step follow-
ing biological oxidation and lime treatment. This process was tested on
total kraft mill effluent on a semi-pilot plant scale and was also run
without the lime treatment step to test the effectiveness of carbon in
reducing the effluent color.
Coagulation Techniques
Smith and Chrlstman ( 72 ) tested the effects of alum and ferric chloride
for the removal of color from kraft mill effluents in the laboratory.
Tests were run on both hard and softwoods. The optimum dosage of alum
on hardwood wastes was found to be 150 mg/1. A color reduction of
89 percent was achieved from an initial color of 710 units. Softwood
kraft effluent was found to require a dosage of 300 mg/1. Ferric
chloride coagulation of softwood waste required an optimum dosage of
286 mg/1 and produced 87 percent removals.
Middlebrooks, et al. reported on the laboratory investigation of alum
and six organic polyelectrolytes for the removal of color from kraft
mill wastewater (73). They report little difference in the perfor-
mance of the six polyelectrolytes. Alum produced good results, but
resulted In approximately three times the volume of sludge. Color
removals averaged 95 percent.
Comparison of System Efficiencies
Timpe and Lang ( 34 ) report that the biological-carbon treatment sequence
utilizing four columns in series reduced color of total kraft effluent
to 212 units which they state is too high for reuse in some areas of the
mill. This is shown in Table No. 11. They estimate an additional three
columns would be required to produce the goal of 100 color units.
The primary clarification-carbon system tested by Timpe again used
four columns. Color was reduced to 185-202 units. This is shown in
Table No. 12. As with the biological-carbon system, it was estimated
that an additional three columns would be required to reach 100 color
units.
93
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TABLE 11
COLOR REMOVAL IN BIOLOGICAL OXIDATION -
CARBON ADSORPTION SEQUENCE AT 15 GPM (2.3 GPM/Fr2) ( 74 )
Range Average
Feed to bio-oxidation, APHA CU 430-2500 1100
Feed to carbon, APHA CU 460-1100 740
Product from carbon, APHA CU 42-400 212
Removal by bio-oxidation plus filter,% - 33
Removal by carbon, % of feed to carbon - 71
Total removal % feed to bio-oxidation - 81
Rate of removal by carbon, CU/g hr 0.51-1.00 0.77
Note: Color measured at pH 7.6 after 0.8 micron Millipore filtration.
TABLE 12
COLOR REMOVAL BY PRIMARY CLARIFICATION -
CARBON ADSORPTION SEQUENCE ( 74 )
Trial 1
Trial
Flow rate, gpm
10
5
Flow rate, gpm/ft
1.42
0.71
Feed to carbon, APHA CU
925
1160
Product from carbon, APHA CU
185
202
Removal by carbon, %
80
83
Rate of removal by carbon, Cu/g hr
0.69
0.46
Note: Color measured at pH 7.6 after 0.8 micron Millipore filtration.
94
-------
DRAFT
The clarification-lime-carbon system produced the best results of the
three systems. In the lime treatment system, the investigators found
that color removal increased from 70 percent at a dissolved Ca concen-
tration of 80 mg/1 to 86 percent at a Ca concentration of 400 mg/1.
Lime dosages ranged from 318 to 980 mg/1. This reduction is shown
graphically in Figure 23. Color removal in the carbon columns
(2 columns in series) was also found to be dependent on Ca concentra-
tion. Color in the effluent remained at about 60 units at calcium
concentrations above 80 mg/1. TOC levels after carbon treatment also
varied with Ca concentration, remaining fairly constant with Ca con-
centrations above 80 mg/1. TOC levels after carbon treatment also
varied with Ca concentration, remaining fairly constant with Ca concen-
trations above 40 mg/1. Color removal through the carbon columns in
the soluble calcium range of 69-83 mg/1 averaged an additional 21 per-
cent, to give an overall reduction of 90 percent. This is shown in
Table 13. Water of this quality was considered suitable for reuse.
Operation of the FACET system following lime treatment, as reported by
Timpe, produced similar results to the two carbon columns after filtra-
tion. This is shown in Table 14.
Smith and Berger (70) report a total color removal in the four stage
(lime - carbonation - oxidation - carbon) system of 99.5 percent. In
the three stage system (no oxidation) the total removal was again 99.5
percent. This is shown in Table 15.
Thibodeaux and Berger (70) report that the color of unbleached kraft
effluent was reduced to 10 and 15 units in two separate pilot runs
using the massive lime-biological-carbon system. Raw effluent color
was 4800 and 3000 units respectively. This is shown in Tables 16 and
17.
McGlasson, et al report that finalvcolor of 40 units was readily achiev-
able by a biological oxidation, lime, carbon treatment system.
Operation Considerations
Timpe and Lang (74 ) concluded that the use of a sand filter ahead of
the carbon system did not provide enough benefit to warrant considera-
tion in a full-scale installation. They also noted concentrated bio-
activity in the top one- or two-foot layer of the first column in
series which caused plugging. Backwashing was required every one or
two days. It was also noted that mechanisms other than adsorption con-
tributed substantially to color removal. This mechanism has been
referred to as a coagulation of the colloidal color bodies at the surface
of the carbon particle. In the section on "System Efficiencies," it was
explained that in Timpe's lime-carbon system, lime dosages were recom-
mended to control the dissolved calcium concentration at about 80 ppm.
95
-------
CO
%
rv
nr
Q.
of
O
—I
o
o
<
3C
D.
<
u,
O
-J
<
>
o
cS
LLi
cc
100
90
80
70
60
50
40
30
20
10
0
—
•° -D
cPc>
cro
-o
/o
o
o
—
o
1
1 1
1
1
1
1
40 120 200 280 360
0 80 160 240 320 400
SOLUBLE CALCIUM FROM LIME TREATER, MG/L
FIGURE 23 COLOR REMOVAL IN LIME TREATMENT AS A
FUNCTION OF SOLUBLE Ca IN WATER (74)
-------
TABLE 13
COLOR REMOVAL BY LIME TREATMENT - CARBON ADSORPTION
SEQUENCE AT SOLUBLE CAICIUM RANGE OF 69 - 83 rag/1 (25)
lime dosage, CaO, rag/1 523
pH of feed to carbon adsorption 11.3
flow rate to carbon adsorption, gpm 10
No. of carbon columns 2
Color, TOC,
Concentrations: APHA pH 7,6 mg/1
to lime treatment 852 272
to carbon columns 252 177
from carbon columns 76 100
% removals from feed to lime treatment:
in lime treatment 70 35
in carbon adsorption 21 28
total 91 63
97
-------
TABLE 14
REMOVAL OF COLOR AND TOC BY
FACET CARBON ADSORPTION FOLLOWING LIME TREATMENT FOR 12-DAY PERIOD
10/20 THROUGH 11/6 (25)
Conditions:
Water feed rate 10 gpm
Carbon feed rate 2,7 lb/hr = 4.5 lb/1000 gal
Carbon in system 605 lb
Carbon slurry density 14.3 g/100 ml slurry
Stages 3
Color, C.U. TOC
Removals: APHA pH 7,6 mg/1
Feed 157 158
Product 73 101
Percent removal 54 36
Removed, mg/g carbon 214 136
Removal rate, mg/g x hr 0.71 0.46
98
-------
TABLE 15
WASTE WATER RENOVATION—SUMMARY OF RESULTS (69)
5-DAY BOD COLOR
Four-stage process Three-stage process Four-stage process Three-stage process
Treatment
Step mg/liter 7. Removal mg/liter X Removal Units % Removal Units % Removal
Raw
Max.
1430
265
12,000
5250
Kin.
225
206
1,000
240
Avg.
723
221
5,200
3558
Lime
Max.
740
144
1,000
450
Min.
170
69
90
10
Avg.
395
45.5
102
54
358
93
185
95
Biol.
Max.
135
1,000
Min.
21
200
Avg.
48
88
365
0
Carb on
Max.
80
84
15
55
Min.
0
15
10
0
Avg.
23
53
32
68.5
13
96.5
23
87.5
Total
23
97
32
85.5
13
99.5
23
99.5
Tests Conducted on Bleached and Unbleached Kraft Effluents.
-------
TABLE 16
RENOVATED WATER ANALYSIS (70)
UNBLEACHED KRAFT LINERBOARD TOTAL HILL EFFLUENT
PILOT PLANT RUN NO. 1 50 GALLON BATCH OPERATION ( )
Constituent
Turbidity, ppm
Color, units
pH
Hardness, ppm CaC03
Dissolved solids, ppm
Chloride, ppm
COD, ppm
BOD, ppm
Na., ppm
Desired Range
5-25
0-80
6.5-7.7
5-200
50-500
10-150
0-12
0-5
Effluent
4800
8.7
107
3380
110
Lime
tat"
Obtaine
Bio
Treatmen
Carbon
818
1400
140
11.5
7.1
2510
140
460
1130
65
200
9.1
86
2650
36
201
8
1600(d)
10
10
8.7
61
2500
36
1
2
1400
Notes: (a) 8.40 lbs, reburned lime slaked and added to raw effluent (equivalent to
20,000 ppm Ca(0H)2).
(b) Extended aeration for 10 days. One'gallon fertile lake water added as seed
material. NH^OH, HNO3 and H3PO4 added as nutrient. H2SO4 added to neutralize.
(c) Carbon columns containing 12x40 mesh activated carbon furnished by Pittsburgh
Carbon. Contact time in the carbon bed was 8.2 minutes.
(d) Possible NH/+ interference.
-------
TABLE 17
RENOVATED WATER ANALYSIS . (70)
UNBLEACHED KRAFT LINERBOARD TOTAL MILL EFFLUENT
PILOT PLANT RUN NO. 2 50 GALLON BATCH OPERATION
Obtained by Treatment
Constituent
Turbidity, ppm
Color, units
pH
Hardness, ppm CaC03
Dissolved Solids, ppm
Chloride, ppm
COD, ppm
BOD, ppm
Na, ppm
Desired RanRe
5-25
0-80
6.5-7.7
5-200
50-500
10-150
0-12
0-5
Effluent
Lime
(a)
Bio
(b)
Carbon
(c)
Notes: (a)
(b)
(c)
Ca (0H)2).
Extended aeration for 8 days. C
material. HNO3, H3PO4 added as nutrient
3000
100
200
15
7.5
12.1
8.2
8.5
-
964
1000
866
4190
2610
3070
2800
160
200
130
130
1430
740
(135)(d)
(80)
(d)
320
230
230
230
added
to rav effluent
(equivalent
to 7500
ppm
gallon
fertile lake water added as
seed
H2SO4 added to neutralize.
Carbon columns containing 12x40 mesh activated carbon furnished by Pittsburgh
Carbon. Contact time in carbon bed was 1.6 minutes.
(d) Estimate, incubator problems.
-------
A benefit of this, as reported, Is the elimination of the necessity to
carbonate the effluent to remove the calcium. Higher dosages could make
carbonation required prior to reuse of the effluent. The lime treatment
system also produced a sludge that dewatered readily to 70 percent
solids. The authors also state that lime treatment to higher dissolved
calcium levels of 400 mg/1, followed by carbonation and carbon tteat-
ment did not Improve color reductions.
Timpe and Lang are enthusiastic about the possibilities of the FACET
system. They state that the rate of TOC removal was 4.7 times the rate
of removal in columns. Also, the degree of color removal was the same
as in the columns, but with one-fifth the amount of carbon. More work
is planned.
The work performed by Timpe has been directed towards reuse of the
treated effluent. A6 such, the degree of treatment obtained is less
than typical discharge standards. At this time, the effect of recycled
effluent on mill processes has not been tested. Timpe and Lang are
confident the kraft process contains unit processes by which any buildup
in contaminants due to recycling can be purged from the system (75).
Smith and Berger (69) found that elimination of biological oxidation in
the lime - carbonation - biological - carbon sequence did not affect
color reduction and BOD reduction remained about 85 percent when treat-
ing effluents with a moderate raw BOD. They point towards further
research toward improved BOD reduction in the lime stage and use of
more effective carbons. They also look to requirements for advanced
treatments leading to recycle of waste waters and see the possible
elimination of biological systems as recycle becomes more Important.
It should be noted that some of the above references on color removal
apply to the bleached kraft segment of the industry, which will be
the subject of a later report. Such references are included here
because they also apply, directly or indirectly, to the unbleached
kraft subcategory of this report. More specific discussions on
trials on bleached kraft mills will be presented in the subsequent
report.
ADVANCED WASTE TREATMENT (AWT)
Introduction
In order to establish reasonable effluent guidelines, the current and
future status of various Advanced Waste Treatment systems, and the
applicability to the subcategories of the pulp and paper industry under-
standably must be evaluated. Specifically, areas of concern are:
1. Removal of turbidity and colloidal and suspended solids
2. Removal of dissolved salts and dissolved solids
3. Removal of refractory organics
4. Removal of nutrlentB
102
-------
FT
High race filtration, either sand or mixed media, has been used for
effluent polishing in the domestic field, but to date has not been used
in the pulp and paper industry subcategories under study for effluent
treatment. Reverse osmosis has been extensively investigated for possi-
ble application within the pulp and paper industry. All of the work,
however, has been undertaken on a pilot plant basis. The progress made
with reverse osmosis systems within the past five years suggests that it
could in the future be a very valuable tool in waste treatment for
removal of color and suspended and total dissolved solids. At present
this method seems particularly applicable to NSSC mills. While many of
the mechanical problems have been solved, membrane life and flux rates
have not progressed to the extent where large scale applications can be
considered. If membrane life can be improved and flux rates increased,
then the total costs could be lowered.
The AWT system which has been evaluated for the removal of dissolved
salts and dissolved solids incorporates unit operations of reverse
osmosis and ion exchange. In addition, specific methods for the removal
of phosphorus and nitrogen compounds have been considered.
Ion exchange has been extensively employed for treating water, but its
application to waste treatment has been negligible. Research and pilot
plant projects have been undertaken to determine its efficiency for
removing dissolved salts and dissolved solids from waste streams. De-
pending on the type of ion exchange process, regenerate disposal could
be a problem. In addition to the removal of total dissolved solids and
dissolved salts, specific ion exchange processes for the removal of
nitrogen and phosphorus compounds have been employed in several domes-
tic facilities but not in the treatment of pulp and paper waste flows,
primarily because only the ammonia NSSC base mills are high in nitrogen.
Phosphorus compounds are not a problem in the industry.
The AWT systems which have been considered for the removal of trace
refractory organics are activated carbon, chlorination, and oxonatlon.
The activated carbon process has demonstrated its applicability to the
treatment of municipal wastes at full plant scale while pilot and labora-
tory studies have shown the potential of its use in the treatment of
pulp and paper mill wastes. The potential of chlorination and ozonation,
however, Is not well documented. While there has been limited investi-
gations concerning the general use of chlorination or ozonation for the
removal of trace refractory organics, there are no plant scale operations.
Turbidity and Colloidal and Suspended Solids
The primary advanced waste treatment systems for the removal of turbid-
ity and colloidal and suspended solids are: 1) sedimentation, coagula-
tion, and flocculatlon followed by settling; 2) filtration; and 3) re-
verse osmosis. The majority of the work undertaken for coagulation and
flocculatlon of pulp and paper mill wastes for the subcategories under
study has been undertaken in conjunction with color removal.
103
-------
Filtration, either sand or multi-media, is a commonly used process in
the advanced waste treatment of domestic waste waters for removal of
suspended solids. Its use, however, for the removal of turbidity and
colloidal and suspended solids from mill effluents is not documented in
the literature.
The reverse osmosis (hyperfiltration) process has received considerable
attention within the pulp and paper industry during the past several
years as a possible economic means of sufficiently treating the spent
pulping process waters for major internal reuse. The initial work with
membranes was in conjunction with an electrodialysis system ( 76 )•
Electrodialysis investigations of pulp liquors provided important back-
ground on new membrane processes such as ultrafiltration and reverse
osmosis. The application of reverse osmosis membranes has been centered
on concentrations of dilute streams in the range of one-half to one per-
cent suspended solids ( 39 ) ( 77 ).
The Pulp Manufacturers Research League and The Institute of Paper
Chemistry have investigated the reverse osmosis process for treatment
of pulp and paper mill waste waters under a project partially sponsored
by the Office of Research and Monitoring of the Environmental Protec-
tion Agency (77). Their studies led to confirming trials conducted in
field demonstrations ranging from 18,900 to 189,300 liters per day
(5000 to 50,000 gallons per day) on five different waste flows. The
five field demonstrations were undertaken on:
1. Ca Base Pulp Washing and Cooling Waters
2. NSSC White Water
3. NH3^Base Pulp Wash Water (also Calcium Hypochlorite Bleach
Effluent)
A. Kraft Bleach Effluent (also Kraft Rewash Water)
5. Chemimechanical Pulping Wash Water
Their study concluded that the reverse osmosis process is an important
new tool for concentrating and recovering solutes in dilute pulp and
papermaking effluents (77). They obtained membrane rejections of 90
to 99 percent for most components in the feed with the exception of low
molecular weight salts and volatiles which were less well rejected.
One mill has also undertaken detailed studies for the use of reverse
osmosis as a unit operation for producing water suitable for process
reuse under a program also partially funded by the office of Research
and Monitoring of the Environmental Protection Agency^( 39 ). This study
included the operation of proprietary reverse osmosis equipment on a
pilot basis by vendors simultaneously and continuously on the same feed.
This allowed the development of operating techniques applicable to the
104
-------
particular feed and development of design criteria for the design of a
full scale production facility. This study also concluded that the
reverse osmosis process is effective in concentrating the dilute waste
stream while producing a clarified water flow that can be recycled for
process purposes ( 39). The concentrated stream would be directed to
the fluidized bed reactor operating as part of their chemical recovery
system. Three basic types of reverse osmosis membrane surfaces are
available:
1. Capillary fiber
2. Sheet membrane (spiral round)
3. Tubular
Tubular membranes have been found to be the most suitable in the work
that has been undertaken because capillary fiber and sheet membranes
were more subject to clogging problems (77). Most of the work with
reverse osmosis has been concerned with the use of cellulose acetate
membranes, but some work with dynamic membranes, or replaceable mem-
branes, is receiving more attention as it could substantially reduce
the cost of reverse osmosis systems ( 76)( 78).
It is stated by Beder, et al that the reverse osmosis process would
best fit into a treatment scheme following primary treatment, prior to
activated carbon polishing if the benefits derived from the improved
solids removal and the elimination of pretreatment with massive lime
and large scale activated carbon are greater than the incurred loss of
membrane capacity resulting from lower flux rates (79). While hyper-
filtration is very effective in removing color and macromolecular
organic compounds, certain lower weight molecular organic compounds
are not rejected by the reverse osmosis process and activated carbon
polishing would be required, for certain uses.
Johnson, et al state that if color removal only is necessary, the ultra-
filtration which is not as effective as hyperfiltration in removal of
organic matters and solids, but is very effective in color removal,
would be satisfactory ( 78)•
The efficiency of the reverse osmosis process for several pulp and
papermaking waste waters are presented in Table 18 (77).
The waste flows had to be pretreated by passage through a 40 mesh
screen and the temperature adjusted to a safe operating range to
protect the cellulose acetate membranes (below A0°C) ( 77)
105
-------
The extensive pilot testing undertaken by a sodium base NSSC mill
showed general rejections by the reverse osmosis process as follows
( 76 ):
Total Solids - 99.7%+
BOD5 - 98.6%+
Color-Optical Comparator - 99.6%+
Na - 99.5%+
Color-Spectrophotometer - 99.8%+
The mixed media polishing filters can be used with or without addition
of chemicals. This polishing filter is necessary when high quality
water is required, but if the water is to be used for discharge to a
natural stream, the use of such a filter is probably not justifiable
(80 ).
The work by the Institute of Paper Chemistry indicated that fouling of
reverse osmosis membranes by suspended particles, colloidal suspensoids
TABLE 18
SUMMARY OF RESULTS OF TREATMENT BY REVERSE OSMOSIS (77)
REPORTED REJECTION - %
WASTE TOTAL
FLOW SOLIDS BOD COD BASE COLOR WATER RECOVERY
Calcium Sulfite 87-98 69-89
NSSC 96-98 87-95
Ammonium Sulfite 93-96 77-94
Kraft Bleach 91-99 85-97
87-95 95-99Ca
99
80-90
96-98 82-95Na
99+
72-92
92-97 92-98NH3
99
65
97-99 83-95Na
99+
—¦
106
-------
DRAFT
of large molecular weight organics, etc., could be partially controlled
by pretreatment, by periodic pressure pulsations, and by periodic wash-
ing of the membrane surfaces (39). Self-cleaning, high velocities of
flow were found to be the most likely means of maintaining high flux
rates through the membrane, especially with the newer high performance,
tight surface membranes that became available in 1971. It was reported
that minimum velocities of 0.61 meters per second (2 feet per second)
overcame concentrative polarization, but 0.91 meters per second (3.0
feet per second) were required to maintain adequate mass transfer
rates (39). It was also stated that concentration polarization did
not appear to seriously affect performance at operating pressures below
55.4 atm. (800 psig).
Present commercial hyperfiltration membranes cannot be operated at tem-
peratures much above ambient and cooling of many pulping effluents is
therefore necessary. Dynamically formed membranes, however, have been
shown to suffer less from these disadvantages and may be preferrable
when a high degree of salt removal is not required (78). In addition,
ultrafiltration membranes are more open than the more tight reverse
osmosis (hyperfiltration) membranes and while rejection for colored
ligonsulfonates are high, other components are rejected to a much less
satisfactory degree. Research is being carried out to develop improved
rejection with ultrafiltration membranes because it has higher flux
rates than hyperfiltration and the advantages of simplified equipment
design (76). In addition, a major roadblock delaying the practical
use of reverse osmosis in waste treatment lies in the several causes of
short life expectancy in the membrane system. Membrane manufacturers
should be encouraged to obtain goals of a minimum three-year life
expectancy for these membranes (77). In addition, membrane develop-
ment should include a capability for operating at wider ranges of pH
and temperature (77) and higher flux rates.
Dynamic membrane studies should be advanced to achieve higher levels of
solid rejection without serious reduction in permeate rates and flux
rates. The development of these membranes could substantially improve
performance and cost parameters ( 78)( 81) ( 71).
Dissolved Salts and Dissolved Solids
Processes which can be used for the purposes of removing dissolved salts
and dissolved solids from pulp and papermaking waste flows are of pri-
mary concern. In work undertaken by Beder and Gillespie (79), it is
stated that process water for bleached and unbleached kraft production
should contain less than 500 and 250 mg/1 of total dissolved solids,
respectively. In addition, chlorides, because of their corrosive nature
should be less than 150 mg/1. The ultimate goal of the current federal
water pollution control legislation will require that certain portions
of the waste stream be treated to achieve the above TDS and chloride
levels if substantial reuse is undertaken. The prime unit processes
107
-------
DRAFi
that could be employed to achieve high degrees of TDS and chloride re-
movals are reverse osmosis and ion exchange.
Pilot work at a sodium base NSSC mill (39) showed average soluble solids
rejections of 99+ percent, with product water soluble solids ranging
from below 100 mg/1 to about 760 mg/1 depending on the percent of feed
solids. Average rejection of sodium was 99+ percent, with product water
sodium ranging from less than 20 mg/1 to about 180 mg/1 depending on
the percent of feed solids.
Table 19 shows the total solids removals with reverse osmosis achieved
in the work undertaken by the institute of Paper Chemistry (77).
The reported data from pilot and laboratory work indicated that reverse
osmosis is very effective in removing TDS and chlorides from selected
pulp and paper industry flows. The ultimate concentration of each
element, however, will be dependent on the initial concentrations and
the recovery and treatment processes preceding reverse osmosis.
Ion exchange has been a well-known method for softening and de-ionizing
water, but application to wastewater treatment has been negligible pri-
marily because high molecular weight organic compounds present in waste-
water have a deleterious affect on most anion exchange materials and
disposal of regenerates is a major problem. New types of resins have
been developed, however, that are less affected by organics. As pointed
out by the work undertaken by Kreusch and Schmidt ( 82) separation
techniques using ion exchange demineralization are known, but their
application to waste treatment is not generally practiced, nor is there
sufficient information on such a system to predict performance.
As pointed out in the work undertaken by Timpe, et al, ( 34), the DESAL
process is a de-ionization technique based upon two weak electrolyte
ion exchange resins. The advantages of this process over conventional
ion exchange process are claimed to be:
1. Ability to treat brackish waters at concentrations of 500
to 3000 ppmdissolved solids with negligible leakage.
2. Stoichiometric amount of regenerates required for regen-
eration versus conventional methods which require 200 to
300 percent of stoichiometric amount; therefore, regenera-
tion costs are significantly less.
3. High degree of utilization of theoretical capacity.
The DESAL Process uses three beds of weak ion exchange resins in a cyclic
process. The first bed is a weak base anion exchange resin; the second
bed, a de-alkalization unit, is a weak acid cation exchange resin; while
the third bed is in the free base form for carbonation. The alkaliza-
tion and de-alkalization units can be regenerated with ammonia and
108
-------
draft
TABLE 19
TOTAL SOLIDS REMOVAL (77J
REVERSE OSMOSIS
Waste Flow
Calcium Sulfite
NSSC
Ammonium Sulfite
Kraft Bleach
Feed g/1
18.47-11.05
10.75-5.72
10.31-50.48
/
% Rejection Effluent Cone. Range g/1
87-98
96-98
94-97
2.04 - 0.37
0.68 - 0.32
6.44 - 0.66
109
-------
DRAFT
sulfuric acid, respectively. At exhaustion, the third unit is in the
bicarbonate form, so the direction of flow through the three units is
reversed and the cycle repeated.
The work undertaken by Kreusch and Schmidt ( 82 ) involved ion exchange
studies on sewage effluent from an activated sludge plant.
The waste was pretreated prior to ion exchange with a system that con-
sisted of lime clarification, dual media filtration, and granular
activated carbon filtration to reduce the total phosphate, suspended
solids, and total organic carbon of the wastewater prior to ion exchange.
The investigations included the performance of the following resins :
1. Weak Base Anion Exchange - Bicarbonate Form
2. Strong Acid Cation Exchange - Hydrogen Form
3. Weak Base Anion Exchange - Free Base Form
4. Weak Acid Cation Exchange - Hydrogen Form
5. Weak Acid: Strong Acid Cation Exchange - Hydrogen Forms
Kreusch and Schmidt's ( 82 ) work concluded that the ion exchange pro-
cess with the weak base anion exchange resin - bicarbonate form was not
sufficiently established to use on domestic sewage containing less than
500 mg/1 of dissolved solids. Their work did show, however, that a
system using a strong acid cation exchange resin and a weak base anion
exchange resin can be used without difficulty for a waste water contain-
ing as much as 500 mg/1 of total dissolved solids. In addition, a weak
acid cation exchange resin can be very efficient as the first resin to
demineralize certain waste waters.
The work undertaken by Linstedt et al.(83) showed that a cation-anion
exchange system was very effective in the removal of major ions from a
domestic secondary effluent. The results of this work are shown in
Table 20( 82).
Timpe et al.( 34) state that ion exchange for the de-ionization of par-
tially renovated waste waters is technically feasible for domestic and
pulp and paper mill wastes. In order to successfully use ion exchange
processes, the majority of organics and suspended solids must be re-
moved from the waste stream. In the laboratory work undertaken by
Gregory and Phond (84), the effluent from a well-operated domestic
activated sludge plant was used without any additional treatment. In
the work reported by Berger and Thibodeaus (70) which consisted of
laboratory sized columns and equipment, the selected kraft mill waste
stream was clarified and treated with lime and activated carbon prior
to ion exchange, while the domestic waste used by Kreusch and Schmidt
( 82) was similarly treated.
110
-------
TABLE 20 (83)
BEHAVIOR OF MAJOR CHEMICAL CONSTITUENTS IN RENOVATION SYSTEM
Concentration or Value
Ca++ as CaCOn (mg/1)
Na+ (tng/1)
Cl~ (ng/1)
S04" (tng/1)
Alkalinity as CaC03(mg/l)
COD (ng/1)
Solids
Total (ng/1)
Fixed (tng/1)
Volatile (X)
Turbidity (JTU)
pH
Before
After
After
After
After
Coagu-
After
Recar-
After
Carbon
Cation
Anion
lation
Settling
bonation
Sand
Adsorption
Exchange
Exchange
62
205
62
0
49
44
44
-
-
0.7
-
53
48
42
-
-
-
2.5
145
130
127
-
-
-
0
175
260
139
-
-
-
5.9
131
102
-
61
16
12.5
10.8
431
377
336
254
233
68
24
312
257
237
172
170
42
15
27.6
31.8
29.7
32.3
27.0
38.2
37.5
16
1.5
2.3
4.1
0.23
0.25
0.23
7.3
11.4
7.6
8.0
8.8
3.0
4.8
£
"Tt
-------
DRAFT
If the waste streams are not properly pretreated prior to Ion exchange,
severe operational problems due to clogging will be encountered. With
biological treatment, the waste stream probably would require a minimum
o£ mixed media filtration for suspended solids removal as pretreatment.
Depending on the organic nature of the secondary effluent, it may have
to be pretreated with activated carbon, or reverse osmosis. If the
total dissolved solids of the waste stream exceeds 3000 mg/1, pretreat-
ment with reverse osmosis may be necessary to keep cost of ion exchange
within reason.
Proper disposal of waste regenerates associated with the use of ion
exchange treatment of waste waters must be fully recognized. Effective
regeneration requires regenerate volumes in excess of stoichiometric
quantities. Strong resins require large excesses while weak resins
only require small excesses. In order to greatly reduce the regenerate
volume to be treated, the ion exchange process should consider fraction-
ation of the total effluent during regeneration and'use (82). Acid
wastes are easily neutralized, but precipitated sludges and neutral
brines must be satisfactorily disposed of. Waste regenerant ammonium
hydroxide from the anion exchange resin can be treated with hydrated
lime, with the liberated ammonia recovered and reused.
A summary of common pretreatment requirements prior to the ion exchange
process is presented in Table 21 ( 85).
Trace Refractory Organlcs
The advanced waste treatment systems studied for the removal of- trace
refractory organlcs Include the following: 1) activated carbon, 2)
chlorination, and 3) ozonation. The activated carbon process has
demonstrated its applicability to the treatment of municipal wastewater
at full plant scale. Pilot plants and laboratory studies^have shown the
potential for treatment of pulp and paper mill wastes with activated
carbon. However, the potential of the other processes is not well docu-
mented and there are no plant scale operations utilizing them. The
removal of one specific refractory organic, color, is discussed in de-
tail in a separate subsection.
Activated carbon has been used at water treatment plants to remove or-
ganlcs that caused taste and odor problems in drinking water supplies.
The use of activated carbon as a step in the physical-chemical treatment
process for domestic waste waters or as an add-on to an existing biolo-
gical treatment system is well documented ( 82). Many researchers have
studied the use of activated carbon as a tertiary process for the treat-
ment of pulp and paper mill wastes ( 86)( 87)( 88)( 89)( 90)( 94).
Coates and McGlasson (90) found that activated carbon was capable of
reducing color, COD, BOD, and odor in kraft mill effluents to very low
concentrations.
112
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draft
Constituent
Suspended Solids
Organics
Oxidants
Iron and Manganese
TABLE 21 (85)
PRETREATMENT REQUIREMENTS
FOR ION EXCHANGE
Problem
Blinds resin particles
Large molecules (e.g.,
humic acids) foul strong
basic resins
Slowly oxidizes resins
Functional groups
become labile
Pretreatment Required
Coagulation and filtration
Carbon adsorption or use of
weak base resins only
Avoid prechlorination
Coats resin particles Aeration
113
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One of the highest concentrations of BOD in the whole kraft pulp mill
waste discharge is contained in the evaporator condensate ( 86). Most
of the BOD and COD of the condensate waste is exerted by dissolved
organic material. Hansen and Burgess ( 86 ) found that 75 percent of
the BOD, COD, and TOD could be removed from the condensates by activated
carbon adsorption.
Activated carbon is characterized by an extremely large surface area per
unit weight (450-1800 sq. m/g) (74). This large surface area is one
feature of activated carbon which results in its large adsorption
capacity. It can be separated into two general clissifications; powdered
and granular. The ultimate adsorption capacities of both powdered and
granular carbons are essentially equal (74); however, powdered carbon
has faster adsorption rates than granular (91) (90). The number of
carbon manufacturers and their particular specifications is very numer-
ous. The selection of a specific carbon cannot be made, however, with-
out first testing the carbon under consideration with the particular
effluent to be treated ( 92 )•
The activated carbon process has various configurations which include:
use of granular or powdered carbon, contact in a column or slurry,
fixed or moving beds, upflow or downflow of Influent, series or parallel
arrangement, and continuous or periodic wasting and regeneration of
spent carbon. Treatability of a particular waste by activated carbon
is described by various analytical adsorption isotherm equations which
are covered in depth in the literature. The Freundlich equation is
probably the most frequently used to determine adsorption Isotherm.
However, poor correlation between Isotherm results and column tests
have been reported. This is partially due to the fact that adsorption
is not the only mechanism responsible for the removals of organlcs
through carbon columns. Three functions describe the operation of
carbon columns (93); adsorption, biological degradation, and filtration.
Most of the researchers studying activated carbon have made one common
assumption — i.e., that the effluent from the carbon system should be
of a sufficient quality to permit reuse as process water. According
to Smith and Berger ( 88 ), renovated waste water suitable for reuse can
be obtained without a biological oxidation step, particularly If the
renovation process starts with a moderate BOD5 to 200-300 mg/1. Table 22
presents the pilot plant results obtained by Smith and Berger.
Weber and Morris ( 94 ) and others found that adsorption equilibrium in-
creased with a decrease in pH. The effect on the rate of adsorption
with changes in temperature is not well defined.
Activated carbon will not remove certain low molecular weight organic
substances, particularly methanol, a common constituent of pulping efflu-
ents (89)> Also, carbon columns do a relatively poor job of removing
turbidity and associated organic matter (92 ). Some highly polar or-
ganic molecules such as carbohydrates will not be removed through
114
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TABLE 22 (88)
RESULTS OF GRANULAR ACTIVATED CARBON COLUMN
PILOT PLANT TREATING UNBLEACHED KRAFT MILL WASTE
Columns*
Preceded by Lime
Columns*
Precipitation and
Preceded by Lime
Biological Oxidation
Precipitation
Influent
Effluent
Removal
Influent
Effluent
Removal
Influent
Effluent
Removal
BOD, mg/1
48
23
52%
102
32
69%
82
12
85%
COD, mg/1
—
—
—
—
—
—
320
209
35%
SS, mg/1
—
—
—
—
—
—
115
74
36%
Turbidity, J.U.
—
—
—
—
—
—
35
35
0%
Color, Units
—
—
—
—
—
—
28
0
100%
Odor
365
13
96%
185
23
88%
—
—
—
PH
—
—
—
—
—
—
11.9
10.5
12%
T.S. mg/1
1285
1205
6%
~Columns loaded at 3.6 - 4.0 gpm/ft2
-------
carbon columns (92 )(86 ). However, most of these materials are bio-
degradable and would not be present in appreciable quantities in a
well bio-oxidized secondary effluent (92 ).
Results of laboratory rate studies, by Davies and Kaplan (91 ), using
powdered activated carbon to treat municipal secondary effluents,
showed that 90 percent of equilibrium adsorption capacity could be
obtained in less than five minutes using turbulent mixing. Davies and
Kaplan considered five different contact systems during their labora-
tory Investigation. The systems considered were:
1. Countercurrent agitated tank adsorption
2. Flotation adsorption
3. Diffusion adsorption
4. Packed bed columnar adsorption
5. Upflow column adsorption
Based on their investigation, Davies and Kaplan considered the counter-
current agitated tank system the most promising of the five systems for
the following reasons:
1. The secondary effluent did not have to be filtered prior
to contact.
2. Variable secondary effluent flow rates and effluent COD
concentrations could be readily handled,
3. Maintenance costs were low.
4. Design and operation was simple.
5. The system was truly continuous.
6. COD removals to approximately 5 mg/1 could be achieved.
7. The potential existed for treating primary treatment
plant effluent.
8. Both suspended solids and colloidal material were brought
down with the carbon due to flocculation.
Davies and Kaplan reported that the processes investigated for separat-
ing the powdered carbon from the treated wastewater were not 100 per-
cent effective and filtration of the wastewater was necessary to
remove the carbon. In a full scale operation, the necessity to filter
the effluent might make the use of powdered carbon economically
impractical.
116
-------
Tests by Hansen and Burgess ( 86 ) showed that 70-75 percent of the or-
ganic matter from kraft evaporator condensate could be removed with 0.46
kilograms of carbon per kiloliter (3.8 pounds of carbon per 1000 gallons)
of waste water. It was also determined that an extended contact time
(over 1 hour) showed insignificant additional COD removal. However,
even after six hours of contact there was an effect on the removal of
toxicity which was attributed to other various constituents. The re-
sults of the work by Hansen and Burgess conflict with that reported
by Tempe and others. Other researchers have reported that activated
carbon is not effective in removing low molecular weight organics such
as methanol and other major constituents of evaporator condensates from
the kraft pulping operation. The condensate used by Hansen and Burgess
may have been contaminated with black liquor carry over.
Timpe and Lang (74) ran extensive pilot plant tests for treating un-
bleached kraft mill effluent with activated carbon. Their 114 liter
per minute (30 gpm) pilot plant utilized four different treatment pro-
cesses. They were as follows:
1. Clarification followed by downflow granular carbon columns.
2. Lime treatment and clarification followed by granular carbon
columns.
3. Biological oxidation and clarification followed by granular
carbon columns.
4. Lime treatment and clarification followed by FACET (Fine
Activated Carbon Effluent Treatment). (Subject of a
patent application.)
All treatment processes were operated in the attempt to obtain a treated
effluent with less than 100 APHA color units and less than 100 mg/1 TOC
which would be suitable for reuse. The lime-carbon treatment achieved
the desired effluent criteria and was considered the most economical of
three processes utilizing carbon columns. A relatively small lime dos-
age of 320-600 mg/1 CaO without carbonation prior to carbon treatment
was reported to be the optimum operating condition for the lime-carbon
process. It should be emphasized that the lack of carbonation was a
criteria for optimum treatment. It was determined that the effluent
should contain about 80 mg/1 Ca for successful optimization of treatment.
The required fresh carbon dosage was 0.30 kilograms of carbon per kilo-
liter (2,5 pounds of carbon per 1000 gallons) treated.
With biological oxidation and clarification followed by carbon columns,
the fresh carbon dosage was 0.96 kilograms of carbon per 1000 gallons
(8 pounds of carbon per 1000 gallons) treated.
It was found that non-adsorptive mechanisms accounted for a significant
amount of color and TOC removal in the clarification-carbon process.
117
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It was felt that the removals were not due to any biological degradation
which night have occurred within the carbon columns. It was determined
that the color in colloidal form coagulated on the carbon surface. The
color colloids were subsequently removed as large settleable solids
during the backwashlng process (74). The method of disposal or recycle
of the backwash water was not discussed. The disposal of backwash water
is a major item and cannot be Ignored on full scale designs.
The FACET system studied by Timpe and Lang is the subject of a patent
application (74). It is a multi-stage, countercurrent, agitated system
with a continuous transfer of both carbon and liquid. One of the major
aspects of the FACET system is the use of an Intermediate size carbon
endeavoring to combine the advantages of both powdered and granular
carbon while minimizing their limitations. Equipment size and carbon
inventory are decreased due to the increased adsorption rate of the
intermediate carbon. Timpe and Lange reported that the FACET system
showed distinct advantages over the column adsorption system. Table 23
tabulates the pilot plant results obtained from Timpe and Lang's investi-
gation.
The use of granular activated carbon for the removal of trace refractory
organlcs is technically sound. However, when this degree of treatment
is obtained, the ability to reuse the effluent for process water is
desirable. Powdered activated carbon has not been widely utilized be-
cause of difficult handling problems encountered in carbon recovery and
regeneration (91). Davies and Kaplan (35) reported that the control
of pH or temperature, though advantageous to the operation of the pro-
cess, would be economically Impractical.
Beebe and Stevens (95) utilized a carbon slurry to treat municipal
wastes. They reported a tendency of the compacted slurry in the quie-
scent concentrator to form a gelatinous mass. It became necessary to
agitate the gel to reliquefy it for easy removal.
Davies and Kaplan (91) studied the use of powdered carbon columns.
They found that the columns became clogged with colloidal matter within
a few hours of operaton and pressure drops became prohibitive. They
tried the upflow contact process, but the bed could not be stabilized
and serious channeling occurred resulting in poor COD removal efficien-
cies. Polyelectrolyte flocculation was determined to be the most econom-
ical method to recover spent powdered carbon. It was also determined
that a suspended solids concentration- of 500 mg/1 or more must be main-
tained in the carbon slurry to assure flocculation efficiency.
Bishop et al. (92) ran pilot plant tests on domestic secondary effluent
and reported that organic matter which was adsorbed on the carbon went
septic and produced a breakthrough of turbidity and organic matter.
Timpe and Lang (74) reported similar results. They observed an H£S
odor in the treated effluent which indicated some biological activity
within the first two feet of the carbon column which caused some plugging
118
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TABLE 23
RESULTS OF ACTIVATED CARBON PILOT PLANTS
TREATING UNBLEACHED KRAFT MILL EFFLUENT
Description Of
Carbon Process
Columns
Preceded By
Biological
Oxidation &
Clarification
Inf.
Eff.
Removal
Columns
Preceded By
Primary
Clarification
Columns
Preceded By
Priaary
Clarification
Columns
Preceded By
Lime Treatment
& Clarification
Inf.
Eff. I Removal
Inf.
Eff.
Removal
Inf. IEff. I Renoval
FACET System
Ir.f. I Eff. I Re-oval
Hydraulic
Load, gpm/ft
Carbon
Contact Time, Mln.
BOD, mg/1
TOC, mg/1
Turbidity, J.D.-
Color, Units
Fresh Carbon
Dosage
lb. carbon/
1000 gal.
pH
2.13
I
Cranular
I
140
148
740
57
212
61Z
71Z
1.42
I
Cranular
220
925
83
185
20.5
0.71
I
Cranular
62Z
80Z
310
1160
121
202
28
61Z
83Z
1.42
I
Granular
I
108
I
26Z Removal
177
252
100
5-15
76
2.5
11.3
3.A.
!
Intermediate
44Z
70Z
158
157
101
73*
3.9
l
36Z
54Z
^Filtered
>
-------
problems If the columns were not backwashed every day or two. They
felt because of the low dissolved oxygen concentration that the bio-
logical activity was anaerobic. Chlorlnatlon of the Influent to the
carbon columns appears to eliminate sliming problems caused by bio-
logical activity within the columns.
Timpe and Lang ( 74 ) reported lower rates of adsorption, resulting in
larger projected capital and operating costs, for the biological-carbon
and primary-carbon processes for treating unbleached kraft mill effluent.
The lower rates of adsorption were believed to be caused by coagulation
of colloidal color bodies on the carbon surface. They also determined
that the use of sand filters prior to the activated carbon was not
necessary. The carbon columns operated with a suspended solids concen-
tration of 200 mg/1 without problems when backwashed every day or two.
Filtration or coagulation of the effluent from the FACET process was
necessary in order to remove that formed on the outer surfaces of the
activated carbon granules.
Figure 24 ( 85) Indicates the estimated cost per pound of COD removed
for various influent and effluent COD concentrations and various design
flows.
Chemical oxidation using chlorine or hypochlorite is an accepted means
of disinfection for water supplies and wastewater effluents. Chlorlna-
tlon has also been found useful for the removal of ammonia nitrogen and
odors from wastewater. However, the use of chlorlnatlon for the removal
of trace refractory organics is not a well-documented process. Culp and
Culp (96) report that the costs indicate that chlorine oxidation is
not competitive with activated carbon adsorption for removal of relative-
ly large quantities of COD from municipal wastes. It may offer an
alternate for the removal of very small quantities of organics which
have not been removed by activated carbon or as a temporary means of
reducing the soluble BOD in the absence of adsorption equipment. No
literature has been found that directs its attention specifically to the
applicability of chlorlnatlon to the pulp and paper industry.
Holm (97) conducted a seven-month study of chlorlnatlon of approximately
303 million liters per day (80 mgd) of effluent from a conventional
activated sludge process treating municipal wastewater. He determined
that chlorlnatlon caused a substantial reduction in the BOD5. The BOD
decreased an average of 34.5 percent. Very good effluent or effluent
from a bulking plant was not significantly Improved. Effluent of 12 to
30 mg/1 of BOD was noticeably improved. Holm also monitored the suspended
solids, PO4, and TOD. He found that the suspended solids concentration
increased about 20 percent. He theorized that some of the soluble com-
pounds were "precipitated" into a suspended state by the chlorine. The
PO4 and TOD were not significantly affected by chlorlnatlon. Melners
(98) studied chlorine oxidation, catalyzed with ultraviolet radiation,
for the treatment of domestic wastewater. He found that chlorine will
slowly oxidize only a small fraction of dissolved organic material in
120
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FIGURE 24
ECONOMY IN SCALE - CARBON ADSORPTION SYSTEMS
INFLUENT COD
(EFFLUENT COD
200mq/l
50 mq/I)
INFLUENT COD = 500-700mq/l
(EFFLUENT COD 150 mq/I)
/
40 60 80 MGD
PLANT DESIGN CAPACITY
1. Costs based on ENR = 1400.
2. Unit costs assume an annual capital recovery
factor of 0.0877.
3. Costs include initial carbon inventory, carbon
handling system, and regeneration facilities.
-------
the dark, but in the presence of ultraviolet radiation, rapid ellnina"
tion of large amounts of COD and TOC is possible.
The most Important factor involved in the process vas the selection of
the source of radiant energy. Meiners determined that short-wavelength
radiation (below 300 mu) is more effective than long-wavelength radia-
tion in promoting the chlorine oxidation process. Radiation of 254 mu
was about six times more effective than polychromatic radiation between
300-370 mu. He found that the rate of organic oxidation was increased
by increased radiation intensity; however, lower intensities produce
more overall organic oxidation for a specific amount of absorbed radiant
energy than do higher intensities. It was also established that the
chlorine consumption was directly proportional to the amount of radiant
energy absorbed, regardless of Intensity. The effectiveness of treat-
ment is dependent on the penetration achieved by the ultraviolet radia-
tion. However, the correlation of treatment efficiencies with influent
color and turbidity concentrations was not reported.
Quantum efficiency is the amount of organic oxidation obtained from a
given amount of absorbed radiant energy. Meiners observed higher
quantum efficiencies at low intensities and an increase in quantum
efficiency as the oxidation proceeded.
Meiners determined that mercury-arc lamps were the most practical source
of radiant energy. However, the ideal mercury-arc lamp Is presently
not commercially available. Of those presently available, the low
pressure mercury-arc is probably the most practical.
The most rapid rate of oxidation and the most efficient use of chlorine
was obtained at pH 5. However, the most economic operation may be at
ambient pH values without the addition of caustic for pH control.
Meiners also determined that chlorine concentrations above 5 mg/1 pro-
duced no significant Increase in the oxidation rate. High concentrations
of chlorine were wasteful of chlorine and wasteful of radiant energy.
It was concluded that an optimum chlorine concentration below 5 mg/1
might be established where oxidation rates could be maximized and
chlorine consumption minimized.
Ozone has been used for a number of years at water treatment plants as
a deodorant and disinfectant. It has recently been utilized at munici-
pal wastewater treatment plants to deodorize gases which are emitted
and to disinfect the effluent. Ozone is a very effective disinfectant
and oxidizing agent. It is about thirteen times more soluble in water
than oxygen (99 ). Hulbers et al.( 99 ) have determined that ozone
effectively reduces the COD and TOC content of effluents from municipal
wastewater treatment plants, as well as odors, color, and pathogenic
organisms.
Residual ozone decomposes very rapidly. It has a half-life in drinking
122
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water of about 20 minutes (99). Because of the instability of ozone,
it must be produced at its point of use. The most common methods of
producing ozone are (99):
1. Silent electric discharge in air or oxygen
2. Photochemical conversion of air or oxygen
3. Electrolysis of sulfuric acid
Photochemical conversion is used only where small quantities in very low
concentrations are required. Silent electric discharge is the only
practical and economical method for large-scale production of ozone. In
general, for large ozone usage, use of oxygen with recycle is a more
economical system than using air ( 99 ).
Because of the expense involved, the use of ozonation to oxidize organics
has not in the past been considered a practical form of tertiary treat-
ment. Huibers et al> (99) have studied the use of ozone as a tertiary
treatment process for domestic secondary wastewater effluent. However,
no investigation of its applicability to the pulp and paper Industry
has been found.
Huibers et al.( 99) conducted laboratory scale tests, about 37.85 liters
per hour (10 gallons per hour),on the use of ozone to oxidize organics
remaining in effluent from municipal secondary wastewater treatment
plants. Effluent from a treatment plant using trickling filters was
treated with ozone and virtually all the color, odor, and turbidity were
removed. No living organisms remained, and the COD was below 15 mg/1.
Ozone concentrations from 11 mg/1 to 48 mg/1 as oxygen proved equally
effective.
Rates of COD and TOC removal were very dependent on agitation rates.
Removals were increased approximately twofold using high-shear contacting
rather than low-shear countercurrent contacting. Cocurrent contacting,
mixing effluent and ozone in an injector, proved more desirable than the
use of a turbine agitator. For effective ozonation, good agitation must
be considered the prime objective in contractor design (99).
Low pH resulted in lower reaction rates, but higher ozone utilization
efficiencies.
Ozone oxidizes many compounds which resist biological oxidation. However,
the most readily blo-oxidlzable organics also consume ozone the most
efficiently ( 99)• Chemical clarification prior to ozonation will re-
move a portion of the TOC that is resistant to oxidation by ozone result-
ing in lower final TOC level and less ozone consumption. Ozonation
efficiency was high when COD and TOC concentrations were high. However,
the effluent had an unacceptably high COD and TOC content. Huibers et al.
123
-------
concluded that effluents having high organic content (COD above 40 mg/1)
are more economically treated by a combination of chemical clarification
and ozonation. Effluents with a low organic content require only ozona-
tion.
Because of the short life of ozone and the slow reaction of ozone with
many organics, It was concluded that the best treatment would be achieved
with multi-stage, high-shear, gas-liquid contacting. The half-life of
ozone is approximately twenty minutes. From this, they determined that
a residence time of ten minutes per stage was reasonable. One hour was
needed for a COD reduction from 35-40 mg/1 to 15 mg/1. Therefore, six
stages were necessary. With the required amount of ozone being added
to each stage as it was needed, an overall ozone efficiency as high as
90 percent was obtained.
Chen and Smith (100) reported that ozonation, catalyzed with activated
Iteney-Nickel removed 85 percent of the COD and 60 percent of the T0C
from secondary treatment effluents in two hours under favorable condi-
tions.
Huibers et al*( 99) concluded that tertiary treatment with ozone has
potential of an automated, trouble-free operation with low maintenance.
Initially, they thought that the ammonia in the waste would react with
the ozone but found that this was not the case.
The reduction of TOC is caused by organic molecules decomposing and
giving off carbon dioxide (99). This rate of decomposition was reduced
only at a pH below 7. A lower pH resulted in lower rates of COD
removal because the activity of dissolved ozone was enhanced by higher
pH. Lime dosage resulted in high pH, while alum-acid coagulants gave
the lowest pH. A pH from 6.0 to 7.0 seemed to be optimum for multistage,
cocurrent ozonation.
Removal of Nutrients
Both phosphorus and nitrogen have received considerable attention in the
past five to 10 years because when added to surface waters, excessive
growth of algae and other aquatic vegetation can result. Most pulp and
papermaklng waste flows, fortunately, normally only contain minor concen-
trations of these elements. The effluents of ammonia base NSSC mills
which are high In nitrogen are an exception. When biological processes
are employed to treat the waste flows of the other subcategories, both
phosphorus and nitrogen compounds must therefore be added to provide the
desired treatment efficiencies. The quantities added, however, should
be only those necessary to provide proper biological treatment and the
residual nutrients resulting from these additives should be negligible.
The majority of work being undertaken for treatment of residual pulp
and papermaklng effluents suggest treatment systems that exclude bio-
logical treatment. Because of the above, it is felt that specific
124
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processes for the removal of phosphorus and/or nitrogen will not be
required except in the case of an ammonia base NSSC mill. Therefore,
the information which follows concerns only nitrogen removal.
A selective ion exchange system for the removal of ammonia nitrogen has
been developed (96 )(101)(102) but has not been applied to ammonia base
NSSC mills. The process uses a natural zeolite, clinoptilolite which is
selective for ammonium ions. Regeneration of the clinoptilolite can be
accomplished with a lime slurry which yields an alkaline aqueous ammoni-
ous solution. The spent regenerate can then be processed through an
air stripping tower to remove the ammonia, with recycle of the regenerate
(96 )(101)(102). The work undertaken by Battelle-Northwest (102),
showed that the ammonia can be destroyed by electrolysis of the regener-
ant, which results in the production of chlorine that reacts with the
ammonia to produce nitrogen gas. A preliminary design report was pre-
pared for the design of a 28.39 million liter per day (97.5 mgd) ammonia
ion exchange system to serve the South Tahoe Water Reclamation Plant
(96 ) (102) •
In the work undertaken by Battelle-Northwest and the South Tahoe Public
Utility District (102), ammonia removal of 93 to 97 percent was reported
with a clarified and carbon treated secondary effluent and clarified
raw sewage with a 378,500 liters per day (100,000 gpd) mobile pilot
plant. Ninety-four percent ammonia removal was obtained with a single
29.26 meter (96 foot) deep bed at 150-bed volumes of Tahoe tertiary
effluent, while with a two-column semi-countercurrent operation with
1.43 meter (4.7 foot) deep beds operating at an average of 250-bed
volumes, 97 percent ammonia removal was obtained. Ammonia removal
averaged 93 percent at an average of 232-bed volumes with clarified raw
sewage treated by the two-column, semi-countercurrent operation.
In the work undertaken by the University of California (101), an average
ammonia removal of 95.7 percent was obtained in demonstration studies on
three municipal wastes having an NH3-N content of about 20 mg/1. It is
stated that ammonia removal to less than 0.5 mg/1 NH3-N is technically
feasible, but only with shorter runs and greater regenerate requirements.
When using selective Ion exchange for ammonia removal, the processing of
wastewaters with high Ng+ concentrations may require clarification of
the regenerate to avoid plugging of the bed with Mg (OH)2 (102)* In
addition, Culp (96) states that secondary effluents may require clari-
fication by plain filtration to prevent fouling of the zeolite beds.
Ammonia removal by selective ion exchange is probably best suited in
areas where prolonged periods of freezing weather are encountered and
where very high degrees of ammonia removal must be maintained. Air-
stripping and biological nitrlfication-denitrification may be used in
the warmer climates at a lower cost, but at a somewhat lower efficiency.
NitrlfIcation-denitrifIcation refers to the biological treatment process
utilized to convert nitrogen compounds (generally ammonia) to nitrates
125
-------
i
and nitrates to nitrogen gas. The biological nitrification-denitrifica-
tlon process has been extensively Investigated and reported (96 )(103)
(104)(105) (106) •
The nitrifying bacteria are very sensitive to poisoning by simple sub-
stances, including heavy metals and free ammonia. Before this process
can be used with industrial wastes, therefore, careful testing must be
conducted under realistic conditions.
Eckenfelder, et al. (85) list the following factors that will influence
nitrification:
1. Dissolved oxygen level should be above 1.0 mg/1.
2. pH of activated sludge system should be in the range
of 7.5-8.5.
3. The growth rate of the nitrifiers is temperature related.
Nitrification below 5°C Is minimum, while optimum tempera-
ture is about 32°C.
4. Growth rate of nitrifiers is reduced by chlorates, cyanides,
alkaloids, mercaptans, urethanes, guanldlnes, methylamine,
and nitrourea.
The ammonia stripping process can be generally summarized, as follows:
1. Raising the pH of the water to 10.5-11.5;
2. Formation and reformation of water droplets (can be
easily accomplished in a stripping tower);
3. Circulation of large quantities of air.
Items 1 and 2 above are the same requirements applied to conventional
cooling towers and explains the adaptability of these towers to the
removal of ammonia.
There are very few stripping towers that have been designed for treatment
of wastewaters. As reported by Eckenfelder (85), those towers which
have been constructed were for the treatment of low strength municipal
wastewaters. The most well known work done with air stripping of ammonia
has been done on municipal wastes at Lake Tahoe. A countercurrent strip-
ping tower, 7.62 meters (25 feet) high, 1.83 meters (6 feet) widet and
1.22 meters (4 feet) in depth was used to investigate the various param-
eters affecting air stripping of ammonia. The results of these are
shown in Figures 25, 26, and 27. It is apparent from these figures that
the design of air stripping towers can be such to accommodate any de-
sired ammonia removal up to 90-95 percent removal when ambient air
temperatures are above 20°C. As reported by Culp (96 ) the efficiency
126
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of the tower was substantially reduced below 20°C. Data obtained with
operation of the tower during winter conditions at Lake Tahoe indicated
that the average lower limit of the process will be in the range of
50-60 percent ammonia removal.
The limitations of the use of ammonia stripping towers was first realized
with the winter operations at Lake Tahoe. These limitations are out-
lined as follows (106):
1. When the air temperatures are at 9°C, or below, freezing
problems can occur which will restrict air flow.
2. Ammonia solubility Increases at the lower temperatures,
which results in higher treatment costB.
3. A calcium carbonate scale formation results on the tower
because the lime treated wastes are saturated with CaC03.
The scale could be flushed from the Lake Tahoe Tower, but
at the EPA's Blue Plains Pilot Plant It was hard and
adhered to the tower fill.
Based on the current status of ammonia stripping towers, they probably
will only be used in warm climates. In addition, the hard scale prob-
lems have to be solved.
MONITORING
A necessary element of effective implementation of a program on efflu-
ent limitations guidelines and standards of performance is proper moni-
toring of effluent waste characterises by individual mills. The
following procedures are recommended.
Flow Measurement
A properly designed, installed, and operated flow sensing device should
be utilized to measure the entire flov at each point source. Such
device should be capable of measuring flow over the entire flow range
encountered. The sending device should be recalibrated at least once
each calendar quarter. More frequent recalibrations may be required if
necessary to assure the required accuracy. Detailed records of all
recalibrations should be maintained.
Each flow sensing device should be equipped with a flow integrator capa-
ble of totalizing flow over the required composite period, and over the
entire flow range. Accuracy of the flow sensing-totallzlng train should
be at least within the limits of accuracy of best practicable equipment
currently available, which normally will not exceed +6 percent of actual
flow. Each such device should be equipped with an accurate means of
indicating Instantaneous flow rate, and should be located near the
127
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FIGURE 25
EFFECT OF TOWER DEPTH ON AMMONIA REMOVAL
-J
£
o
s
LU
en
<
h-
2
LU
O
C£
UJ
Ql
100
80
24' Depth
~ 60
Z-
o
40
20
<
c
.
-------
FIGURE 26
EFFECTS OF HYDRAULIC LOADING ON AMMONIA REMOVAL AT VARIOUS DEPTHS
N5
o
bJ
CC
< 60
<
O
2
<
LlJ
O
cr
LU
Q.
100
80
40
20
~*~V v6 1
\ -P-0-
\ A M
\ ®
\ A
i
-s——
©
~
24' Depth
\
\
> {>
>
201 Depth
\/
/
/
^ ^ A
**A
*
12'Depth
«sN
A
A '
—
A
A
1.0
2.0
3.0
40
5.0
6.0
SURFACE LOADING RATE (GPM/FT )
-------
FIGURE 27
EFFECTS ON PACKING SPACING ON AMMONIA REMOVAL
4 x 4 Ir
. Packinc
3 (plastic
truss be
:rs)
-------
flow sensing device. A flow recording device capable of recording flow
rate over a 24-hour period should also be provided for each flow sens-
ing device.
Each such device must be kept as clean as possible, and protected Inso-
far as feasible from the weather and from all factors which may adversely
affect Its operation, maintenance, or accuracy.
Sampling
An automatic compositing sampler should be Installed at or near each
flow sensing device to take a periodic or continuous and representative
sample of the flow passing through the flow sensing device at the time
the sample is taken. The sampling interval should not exceed five
minutes at normal average flow rate. Each liquid withdrawal should be
a quantity whose volume bears a constant relationship to the flow rate
at the time the withdrawal Is made. Each such withdrawal should be
deposited in a light-free compositing container which is maintained at
the temperature prescribed by "Standard Methods for the Examination of
Water and Wastewater" (30). All materials in contact with the sample
should be corrosion-resistant, non-contaminating to the pollutant
analyses described below, and easily cleanable. All surfaces of
the sampling train exposed to the sample must be kept as clean as Is
reasonably possible and all reasonable precautions should be utilized
to maintain the sampler in correct and continuous operation.
The composite sample (or a representative alliquot of thr composite)
should be removed at least every 24 42 hours for analysis, on operating
as well as non-operating days. The flow integrator reading should be
recorded at this time. Persons handling samples shall be trained and
competent in such procedures.
Analysis
Each composite sample (or alliquot) should be analyzed as prescribed by
"Standard Methods for the Examination of Water and Wastewater" for
the following constituents:
1. BOD5;
2. Suspended solids;
3. pH;
4. Total phosphorus;
5. Total kjeldahl nitrogen;
6. The sum of nitrite nitrogen plus nitrate nitrogen.
All analyses should be conducted by trained and competent personnel.
131
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Records and Reporting
The following detailed records should be maintained and kept available
for Inspection for at least three years:
1. Flow meter calibration, recalibration, and malfunction records;
2. Sampler maintenance and malfunction records;
3. Analytical methods used, bench records, results, data, and
summaries;
4. Production tonnage data, how and where measured, and con-
version calculations to moisture-free basis.
Monthly reports should be submitted to the appropriate agency by certi-
fied mail on a monthly basis, and each monthly report should consist of
at least three parts:
1. A dally data sheet for each separate point source discharge;
2. A summary report for the month;
3. A dated cover letter naming the month for which the report
applies, and explaining in complete detail the boxes which have
been checked (if any) on the accompanying daily data sheet(s)
and summary report forms.
132
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SECTION VIII
COSTS, ENERGY, NON-WATER QUALITY ASPECTS,
AND IMPLEMENTATION REQUIREMENTS
COSTS
Actual treatment costs vary to a significant degree from mill to mill,
depending upon the design and operation of production facilities and
other local conditions. Effluent treatment costs which have been re-
ported by the industry itself demonstrate this variance. The projected
costs of achieving the effluent limitations which are proposed herein
have been developed for typical mill sizes in each of the subcategories
under study.
Frequently there is more than one combination of unit processes avail-
able to achieve the proposed effluent limitation guidelines. Where this
is the case the more expensive combination has been considered from a
cost standpoint.
Costs of effluent treatment which are presented have considered the
following:
Investment Coat
Design
Land
Mechanical and electrical equipment
Instrumentation
Site preparation
Plant sewers
Construction work
Installation
Testing
Annual Cost
Interest
Depreciation
Operation and maintenance
Operation and maintenance costs include labor, parts, chemicals, insur-
ance, taxes, solid waste disposal, quality control, monitoring, and
administration. Cost of energy is not included. Productivity increases
or byproduct revenues as a result of improved effluent control are sub-
tracted so that the operation and maintenance costs reported are the
net costs.
133
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All costs are expressed In terms of August 1971 prices. This Is compar-
able to the following cost Indices:
Index
Index @ August 1971
164.5
EPA Treatment Plant Construction Cost
Index (1957-59 - 100)
EPA Sewer Line Construction Cost
166.8
Index (1957-59 « 100)
*ENR Construction Cost Index (1913 ® 100)
1614
ENR Labor Cost Index (1949 ¦ 100)
420
Table 24 illustrates the costs for the recommended treatment
and control technologies for the subject subcategories. Each cost shown
reflects the total amount necessary to upgrade a mill which has only
minimal internal control of spills, minimal recycling and recovery, and
no treatment of waste waters to the specified technology level. It
should be recognized that most mills have some existing capability be-
yond this base line, thus resulting in reduced costs over those shown.
ENERGY REQUIREMENTS
As previously stated, the costs shown above do not Include energy costs.
Specific energy and power prices have been developed based on the follow-
ing:
External treatment
power cost ¦ l.lc/KWH
fuel price - $0.24/million Kg Cal ($0.95/million BTU)
Internal treatment
steam ¦ $1.86/metric ton ($2.05/short ton)
power ¦ 0.6/KWH
The lower power unit price used for internal treatment takes into con-
sideration the lower cost of power generated by the mill, while power
from external sources is assumed for external treatment.
Power costs are reported on Table 25 as annual expenditures.
* Engineering News Record
134
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TABLE 24
TREATMENT COSTS, $000
Type of Cost Technology Level
I II III*
Unbleached Kraft — 1000 Ton/Day
Total Investment Cost 10,270 14,733 7,897
Total Annual Cost 2,427 3,677 1,612
Depreciation and Interest 1,440 2,356 1,175
Operation and Maintenance 987 1,321 437
Kraft-NSSC — 1000 Ton/Day
Total Investment Cost 8,897 14,501 7,555
Total Annual Cost 2,590 3,965 1,760
Depreciation and Interest 1,697 2,695 1,168
Operation and Maintenance 893 1,270 592
NSSC Sodium Base — 250 Ton/Day
Total Investment Cost 3,488 6,008 1,457
Total Annual Cost 1,073 1,586 293
Depreciation and Interest 497 901 208
Operation and Maintenance 576 685 85
NSSC Ammonia Base — 250 Ton/Day
Total Investment Cost 1,406 3,971 1,792
Total Annual Cost 302 823 365
Depreciation and Interest 184 606 260
Operation and Maintenance 118 217 105
Waste Paperboard — 100 Ton/Day
Total Investment Cost 983 1,223 709
Total Annual Cost 215 252 126
Depreciation and Interest 137 178 89
Operation and Maintenance 78 74 37
* Costs for Level III treatment and control technology do not Include
expenditures necessary for Internal mill Improvements. Sufficient
data was not available to establish this portion of the costs.
135
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TABLE 25
POWER COSTS, $000
Type of Mill
Technology Level
Unbleached kraft
1000 ton/day
Kraft-NSSC
1000 ton/day
NSSC-Sodlum Base
250 ton/day
NSSC-Ammonla Base
250 ton/day
Waste Paperboard
100 ton/day
248
232
121
73
44
II
499
503
165
llO^)
42
mTT)
446
362
52
65
23
(1) Costs for removal of nitrogen are not included because of lack of
sufficient data.
(2) Costs for level III treatment and control technology do not include
expenditures necessary for internal mill improvements. Sufficient
data was not available to establish this portion of the costs.
136
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NON-WATER QUALITY ASPECTS OF CONTROL AND TREATMENT TECHNOLOGIES
Air Pollution Potential
There is virtually no potential for an air pollution problem arising
from the external treatment of effluents from unbleached kraft, sodium
base NSSC, or waste paperboard mills, or from unbleached kraft and
sodium base NSSC mills utilizing cross recovery, although such problems
are encountered in sludge disposal.
The physical processes employed in suspended solids removal by these
subcategories do not Involve any activity which would create air pollu-
tion, since detention times rarely exceed six hours, a period which is
not conducive to development of anaerobic or other odors. The subse-
quent biological processes are aerobic in nature when properly designed
and operated, and the products of decomposition consist almost entirely
of carbon dioxide, water, sulfates, and a trace of nitrates, all of
which are odorless. The absence of objectionable odor has been con-
firmed by innumerable field observations by contractor personnel and
regulatory officials. The only odors detectable were the characteristic
odor of wood extractants. These are similar both in terms of character
and intensity to those present in nature.
There are, however, air pollution problems associated with the treatment
of wastes in the ammonia base NSSC subcategory. These take two forms.
First is the odor of ammonia arising from the treatment Itself. While
ammonia is not present in high concentrations, the odors can be objec-
tionable under low-wind conditions close to the treatment site. Second-
ly, the synergistic combination of gaseous ammonia with other elements
in the atmosphere, such as sulfur dioxide, is believed to be responsible
for a localized atmospheric haze under certain conditions. Similar
combinations may be responsible for observed damage to new growth ends
of pine trees.
Odors can arise from land disposal of liquid sludges as a result of
their anaerobic decomposition. These derive primarily from organic
acids and hydrogen sulfide produced on reduction of sulfates dissolved
in the water content of the sludges. Dewatering prior to disposal on
the land arrests such decomposition and represents an adequate odor con-
trol measure, as do land fill practices.
Presently sludge lagooning is largely limited to unbleached kraft mills
on large sites. The low level of odor produced is generally confined to
company property. The practice of decanting free water from lagoons and
returning it to the treatment system has noticeably reduced the odor
level in their immediate environs.
Incineration of sludges produced in the effluent treatment processes
can, without appropriate control equipment, result in the discharge of
particulates to the atmosphere. However, emission control devices are
137
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available to meet state regulatory requirements in most instances. In-
cinerators are either sold with Integral emission control appliances
or are equipped with them on installation. Gaseous pollutant emissions
from such Incinerators are negligible.
In-mill controls which effect a reduction in fiber and additive losses
such as save-alls, recycling of process waters, and removal of dregs and
grits in the unbleached kraft recovery process are not producers of air
pollution. On the other hand, recovery of cooking chemicals in the
kraft process, which, in addition to its principal function of conserv-
ing expensive raw materials, also serves to reduce chemical waste load,
produces odorous sulfur compounds. When these escape the recovery fur-
nace to the atmosphere, they become the major air pollution problems of
the mill. These emissions and measures to control them are described
in a report prepared for an EPA predecessor agency entitled "Control of
Atmospheric Emissions in the Wood Pulping Industry" (107).
Noise Potential
There are no official records of public noise problems arising from the
operation of effluent treatment works by the subject subcategories of
mills. However, based on many years of contractor association with in-
dustry operations, it can be stated that public complaints engendered by
such noise are very infrequent. This is due in all probability to the
remote location of most large treatment works or to their confinement,
in some Instances, to manufacturing or utility areas. Also, the noise
level of most of the devices employed for treatment is generally lower
than that of some manufacturing machinery.
The sources of noise are for the most part air compressors or mechanical
surface aerators supplying air to treatment processes, vacuum pumps*and
centrifuges involved in sludge dewatering, and fans serving sludge
incinerators. With the exception of surface aerators, these devices are
most frequently operated in buildings which serve to muffle their noise.
Small surface aerators are generally found In small mills which are more
likely to be located closer to habitation. Units of this size, particu-
larly those not driven through gear boxes, produce little noise. The
problem of noise emanating from gear boxes is the subject of an extensive
investigation by the Philadelphia Gear Company which manufactures many
of these units. It is anticipated that this study will lead to a reduc-
tion in noise from these sources. Noise produced by the large aerator
units which are usually operated away from built-up areas is neither
high-level nor far-carrying.
It can be concluded that noise produced by equipment used for treating
pulp and paper mill effluent is not a major public problem at present.
Efforts underway to reduce the noise level of mechanical equipment in
general, stimulated by industrial health protection programs, will assist
in preventing it from becoming one.
138
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Solid Wastes and Their Disposal
In addition to sludges produced by effluent treatment, the following
wastes are or can be produced at mills in the subcategories covered by
this survey:
LINERBOARD MILLS
(and Kraft-NSSC)
Bark
Rejects and Screenings
Grits and Dregs
Log Wash Water
Ash
Waste Paper
Garbage
Trash
NSSC CORRUGATING BOARD MILLS
Bark
Rejects and Screenings
Chemical Ash
Ash
Waste Paper
Garbage
Trash
WASTE PAPERBOARD MILLS
Trash
Waste Paper
Fly Ash
Garbage
Linerboard mills which bark roundwood on the premises produce sufficient
bark to fire a boiler for steam generation so the necessity for its dis-
posal is eliminated. Others receive their wood supply in the form of
chips which are a byproduct of lumbering operations, and no bark is
involved.
Rejects and screenings from linerboard mills are either reprocessed,
burned in incinerators or in the bark-fired boilers, or disposed of by
land fill. The latter procedure represents no problem for most of these
mills because of the large mill sites containing considerable waste land.
Grits and dregs from the causticlzlng system of the recovery plant are
139
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Inorganic solids which are generally water carried to a land disposal
site. This is facilitated by their small quantity which amounts to
about 22.5 kilograms per metric ton (45 pounds per short ton) of pulp
produced.
Ash from bark' and coal-fired boilers and screening rejects are as a
rule discharged hydraulically to ash ponds. There the solids settle and
compact and the clear supernatant water is discharged to the mill efflu-
ent system. In some instances, ash and rejects are hauled to a disposal
area away from the mill site. Vet handling of these materials avoids
their being blown into the atmosphere.
Overflow from log washing operations which contains silt and fine bark
particles generally joins the stream carrying ash from the mill.
Waste paper, garbage, and trash attendant to production or accessory
operations and activities are either Incinerated on the site or hauled
away for disposal by contractors engaged in this business.
NSSC corrugating board mills generate most of the kinds of solid wastes
created at linerboard mills and handle them in a similar manner. One
exception is that most of these mills are relatively small operations
which do not produce enough bark to justify a steam-generating bark
boiler. The bark is usually disposed of in incinerators designed for
this purpose.
At NSSC mills where spent liquor is burned in fluidized bed units, ash
consisting of a mixture of sodium carbonate and sodium sulfate Is pro-
duced. This is usually sold to kraft mills to be used as a make-up
chemical replacing salt cake in the recovery system.
At waste paperboard mills, trash such as rags, wire and other metals,
glass, and plastics are removed in the breaker beater and stock cleaning
operations. This material and grit from the rlfflers are disposed of by
land fill on the mill premises or hauled to a suitable location for
disposal in this manner.
The remaining solids wastes such as ash, waste paper, etc., are handled
as described above.
Particulate emissions from incineration of bark and other solid wastes
must be controlled by effective devices such as bag filters or scrubbers.
Research has recently been conducted on solid wastes generated in the pulp
and paper industry and their disposal for EPA's Office of Solid Waste
Management Programs (EPA Contract No. 68-03-0207).
140
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Byproduct Recovery
The unbleached kraft process is the only subject subcategory in which
significant quantities of byproducts are recovered. The two major sale-
able byproducts of this process are turpentine and tall oil, both in a
crude form which is usually refined elsewhere.
Digester relief gases are the source of crude sulfate turpentine. The
gases are condensed and the crude oil fractions decanted from the water
fraction. The turpentine requires distillation to remove the objection-
able odor of the sulfur compounds present. Generally crude turpentine
is shipped from the mills for rectification by chemical plants.
Turpentine yields vary with wood specie (108) and cooking variables. A
1969 study (109) reported yields ranging from 6.3-17.9 liters per metric
ton (1.5-4.3 gallons per short ton) of pulp; its market value was esti-
mated at 18c-36c/metric ton (20c~40c/short ton); and its recovery was
calculated to represent approximately one percent dimunition of the
pollution load in terms of BOD5. Its removal from the mill effluent is
actually of much greater significance since it has a high toxicity level
for aquatic life. It is used primarily in paint thinners and the manu-
facture of insecticides.
A light fraction of the distilled turpentine contains dimethyl sulfide
which can be removed and converted to dimethyl sulfoxide, an excellent
industrial solvent ( 9 ).
Tall oil components are recovered from kraft black liquor at various
points in the chemical recovery system in the form of sodium soap skim-
mings. These are acidified with sulfuric acid to produce tall oil and
the spent acid which consists primarily of sodium sulfate is returned to
the black liquor as chemical make-up. Tall oil consists of a mixture of
resin and fatty acids, and its derivatives are used to make adhesives,
emulsions, paints, disinfectants, and soaps (109).
Tall oil yield per metric ton of kraft peaked in 1968 at about 47.5 kilo-
grams per metric ton (95 pounds per short ton) and has declined to about
39 kilograms per metric ton (78 pounds per short ton) in 1973. (110).
Normal variations occur depending on the fatty content of the wood, skim-
mer efficiency, and other factors. Efficiency of recovery now averages
about 75-80 percent (HI).
Fluctuations in price also occur due to market factors and a considerable
range may be found In the literature. The most recent price quoted is
$72.56 per metric ton ($80 per short ton), a 25 percent increase over
the past five years (110). The economic incentive to increased soap re-
covery may expand the corollary benefits of recovery which have a direct
bearing on raw waste load.
The presence of soap in black liquor accelerates fouling of the evapora-
tors which in turn affects required heat differences. This creates the
141
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necessity for more frequent boil-out during which liquor losses inevita-
bly occur. Frequent skimming of the weak liquor storage tanks is needed
in addition to evaporator skimming to prevent soap being pulled into the
evaporator feed during low liquor inventory. The resultant foaming can
create evaporator upset which will require boil-out to restore stability
(110).
Mill practices which will permit more complete recovery of turpentine
and tall oil are forecast. For example, shorter storage of chips or pre-
cooking extraction would prevent the loss of turpentine and tall oil by
oxygenation prior to pulping. Solvent extraction of the soap from black
liquor could improve recovery efficiencies (111).
On the other hand there are factors which will inhibit recovery of these
byproducts. Increased use of continuous digesters will reduce the yield
of turpentine thus creating a need for an economic method of turpentine
recovery from the black liquor in continuous processes. Mixing pine and
hardwood black liquors reduces the recovery of tall oil and separate
liquor tanks will be required (111). Use of more hardwood, sawmill
wastes, immature wood, and outside chip storage are other adverse fac-
tors (110).
Production of other byproducts, such as methanol, acetic acid, tars,
etc., on a commercial scale is not yet economically feasible. Effluent
limitations and standards are expected to stimulate Increased research
on byproduct recovery in the next decade.
IMPLEMENTATION REQUIREMENTS
Availability of Equipment
Since 1966, when federal water pollution control expenditures began,
various federal and private organizations have analyzed the projected
levels of water pollution control activity and their economic impact on
the construction and equipment industries. As a result, a plethora of
studies has been developed which Is related to the levels of municipal
and industrial water pollution control construction and the respective
markets for waste water treatment equipment. Less information is avail-
able concerning the actual and anticipated levels of expenditure by any
specific Industry.
In recent years, the trend in the waste water equipment industry has
seen the larger firms acquiring smaller companies in order to broaden
their market coverage.
Figure 30shows graphically past expenditures and projected future out-
lays for the construction of industrial waste water treatment facilities,
as well as total water pollution control expenditures. Obviously, the
level of expenditures by industry is related to the federal compliance
142
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-P-
U>
5
i
o
Q
u.
o
0
1
3
2
C.O
70
T2.
YEAR
7A
7Cp
76
i«?ao
figure 28
TOTAL WATER POLLUTION
CONTROL EXPENDITURES
-------
schedule. This will Increase until industry is in compliance with
federal standards. Once that occurs, the level of spending will return
to a level commensurate with the construction of new facilities, replace-
ment of existing facilities, and the construction of advanced waste
treatment facilities.
Figure 29 shows past expenditures for and projected future trends in
total sales of waste water treatment equipment and the dollar amounts
attributable to industrial and municipal sales. This curve closely
follow8 the trend shown in Figure 28.
The data in Figures 30 and 31 related to industrial water pollution
expenditures include only those costs external to the industrial activ-
ity. Internal process changes made to accomplish water pollution control
are not included.
Recent market studies have projected the total available production
capacity for water and waste water treatment equipment. Most of them
have indicated that the level of sales is currently only 30-40 percent
of the total available plant capacity. Several major manufacturers were
contacted to verify these figures and indications are that they are
still accurate. A partial reason for this overcapacity is that the de-
mand for equipment has been lower than anticipated. Production capacity
was increased assuming federal expenditures in accord with funds author-
ized by Congress and conformance to compliance schedules.
For the immediate future, increased demands for waste water treatment
equipment can be absorbed by the existing overcapacity. Long term
requirements will probably necessitate expansion of production capacity
in various product lines where the demand is expected to Increase dra-
matically — specifically, advanced treatment systems and waste solids
handling equipment.
It should also be noted that the capacity to produce waste water treat-
ment equipment could be expanded significantly through the use of inde-
pendent metal fabricators as subcontractors. Even at the present time
Independent fabricators are used by some equipment manufacturers when
work loads are heavy and excessive shipping costs make it desirable to
use a fabricator close to the delivery site.
There appear to be no substantial geographical limitations to the distri-
bution of waste water treatment equipment to industry. In various areas,
certain suppliers may be more successful than others; however, this
seems to be more related to the effectiveness of the sales activities
rather than to as geographical limitation. The use of independent metal
fabricators are subcontractors to manufacture certain pieces of equip-
ment further reduces geographical limitations.
Equipment delivery schedules may vary substantially depending upon the
manufacturer, the current demand, and the specific equipment in question.
144
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900
800
TOO ••
4>oo
soo-
4-00
300-
zoo ¦ -
IOO ¦¦
196.6.
6>8
lO
"72.
YEAR
I*) SO
FIGURE. 29
WASTE WATER. TREATMENT
EQUIPMENT SALtS
-------
-C>
ON
X
u>
0
Z
»-
o
u
Z
0
K
u
3
tit
z
8
3000
ZCoOO
2700
JULY 1977
/ i"3£»0 ±
JUL.V 1983
3040 ±
1800
1400
IOOO
6>oe
1955
I960
I9«
1970
1973 1915 I«il7
I9BO
1983
YEAR
FIGURE 30
ENGINEERING NE.WS RECORD
CONSTRUCTION COST lMDfc*.
-------
IOOO
NATURAL —
STAB1LIZA"
500
lOO
SO
¦AERATED _J
STABILIZATION!
IO
<
ACTIVATED SLUDG»E
\o
IS
5
O
FLOW - MGD
FIGURE 31
LAND REQUIRED FOR
WASTEWATER. TREATMENT
147
-------
Obviously, Che greater the demand or the more specialized the equipment,
the greater the delivery time.
Availability of Construction Manpower
After consultation with the Associated General Contractors of America
and other industry groups, it is concluded that sufficient manpower
exists to construct any required treatment facilities.
This conclusion has reportedly been substantiated by EPA in an Indepen-
dent study (112) although there is still some concern about localized
problems. The Bureau of Labor Statistics has been requested to conduct
another study.
Construction Cost Index
The most detailed study and careful analysis of cost trends in prior
years still leave much to be desired in predicting construction costs
through the next ten years.
During the years 1955 through 1965 there was a very consistent price
rise. The Engineering News Record (ENR) Construction Cost Index in
January 1955 was 644. With slight deviations from a straight line,
costs rose at a steady rate to an index of 988 in December 1965. This
represented an increased cost of 53.4 percent over an 11 year period
of approximately five percent per year.
The first six months of 1966 saw an Increase of 6.6 percent then leveled
off abruptly only to rise sharply again in 1967 at a rate of 6.2 percent,
then increasing to 9.4 percent in 1968.
The increase in costs continued to rise at about 10.5 percent per year
through 1970. During 1971, construction costs rose at the unprecedented
rate of 15.7 percent primarily due to larger Increases in labor rates.
With the application of federal wage and price controls in 1972, the
rate of Increase dropped to 8.7 percent. The firBt three months of 1973
saw some escalation of costs due to allowable materials price gains.
EPA determined the increase in Treatment Plant Construction Cost during
this period to be 3.1 percent. This compares with a rise of only 0.9
percent during the previous three months.
The opinion of some officials of the Associated General Contractors is
that,the rate of cost increase for general construction work, including
waste water treatment and industrial construction, should average no
more than five to six percent over the next several years. This is,
therefore, the basis used for extension of the ENR Index curve at an
annual six percent increase for construction costs through the year 1983.
148
-------
This is shown in Figure 32.
Land Requirements
Land requirements for a number of external treatment systems have been
evaluated and are shown in Figure 35 for a range of plant sizes, in-
cineration or off-site disposal of dewatered sludge has been assumed.
Should sludge lagoons be used on site, additional land would be required.
Time Required to Construct Treatment Facilities
The time required to construct treatment facilities has been determined
for a range of plant sizes and for two different project contract possi-
bilities. The treatment sizes evaluated were under five MGD, five to 10
MGD, and over 10 MGD. The contract bases evaluated were 1) separate
engineering and construction and 2) turnkey performance. The components
considered for both approaches included preliminary engineering, final
design engineering, bid and construction award, and construction.
It is concluded from reviewing the data shown in Figure 34 that it should
be possible in all cases to meet the implementation requirements of the
July 1977 deadlines.
149
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SITE
IV.GD
UMOcR 5
COMV.
UNDER 5
TURNKEY
5-10
COMV
5-10
turnkey
On
o
OVER IO
COSJV
OVER IO
TURNKEY
197&
JFMAMJJASOND
1975
JFM A M J J A S 0 N 0
J I I I I I J
197b
JFM AMJJ ASOND
_J _ 1 _L _J__L
1977
J F H AMJJ A
PRELIMINARY ENGINEERING
FINAL DESIGN ENGINEERING
bid Ann rnNSTRiirTinN award
CONSTRUCT I ON
FIGURE 32
TltvIE T?&QLMR£D TO
CONSTRUCT WASTE:WATTtR FAC\UT\ES
COMV£KlTIOKJA\_ 4 TURKlKEiY COJT^ACT.5
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DRAFT
SECTION IX
BEST PRACTICABLE CONTROL
TECHNOLOGY CURRENTLY AVAILABLE
INTRODUCTION
The effluent limitations which must be achieved by July 1, 1977 are to
specify the degree of effluent reduction attainable through the appli-
cation of the Best Practicable Control Technology Currently Available.
Best Practicable Control Technology Currently Available is generally
based upon the average of the best existing performance by plants of
various sizes, ages, and unit processes within the industrial subcate-
gory.
Consideration must also be given to:
a. the total cost of application of technology in relation to the
effluent reduction benefits to be achieved from such applica-
tion;
b. the size and age of equipment and facilities involved;
c. the processes employed;
d. the engineering aspects of the application of various types of
control techniques;
e. process changes;
f. non-water quality environmental impact (including energy re-
quirements) .
Also, Best Practicable Control Technology Currently Available emphasizes
treatment facilities at the end of a manufacturing process but includes
the control technologies within the process itself when the latter are
considered to be normal practice within an industry.
A further consideration is the degree of economic feasibility and engi-
neering reliability which must be established for the technology to be
"currently available." As a result of demonstration projects, pilot
plants, and general use, there must exist a high degree of confidence in
the engineering and economic practicability of the technology at the
time of commencement of construction or installation of the control fa-
cilities .
151
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
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DRAFT
EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION OF BEST PRACTI-
CABLE POLLUTION CONTROL TECHNOLOGY CURRENTLY AVAILABLE.
Based upon the information contained in Sections III through VIII of
this report, a determination has been made that the following point
source discharge guidelines for each identified pollutant can be ob-
tained through the application of the best practicable pollution con-
trol technology currently available:
Recommended Effluent Guidelines,
Pounds Per Short Ton of Production
Subcategory
BODc
Suspended Solids
pH Range
Unbleached Kraft 4.0
NSSC-Sodium Base 10.0
NSSC-Ammonia Base 10.0
Kraf t-NSSC
(With Cross Recovery) 7.0
Waste-Paperboard 2.0
6.0
10.0
10.0
7.0
2.0
7.5-8.5
7.2-7.8
7.2-7.8
7.5-8.5
6.0-7.5
The allowable pounds of BOD^ and suspended solids per short ton of pro-
duction are to be based upon monthly averages of daily values as deter-
mined from industrial records. It is expected that values on any given
day could exceed these guidelines. Further, values may be adjusted to
reflect variations in performance as a result of changes in materials
mix, ambient air temperature^ effect on waste treatment process perfor-
mance, and other local conditions.
Production capacity is defined as the total production off the machine,
including re-processed broke. Daily production, in air-dry tons, is
defined as the highest average level sustained for seven consecutive
operating days of normal production.
Values are intended to reflect the net pounds per ton of product which
are attributed to the industrial operation, and do not account for "back-
ground" pollutional loads which may have existed in the process water
prior to use by the industry.
Effluent limitation guidelines on color and nitrogen are not applicable
to best pollution control technology currently available.
152
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
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DRAFT
IDENTIFICATION OF BEST POLLUTION CONTROL TECHNOLOGY CURRENTLY AVAILABLE
Best pollution control technology currently available is the same for
all subject subcategories with regards to external treatment of indus-
trial wastes. However, currently available and applicable technology
varies between subcategories for internal control measures. The follow-
ing is a discussion of both these internal and external controls.
Internal Control
Unbleached Kraft (pulp mill only)
a. Hot Stock Screening
As explained in Section VII, this is a process modification in
which the pulp is passed through a fibrilizer to fractionate
knots and then through a hot stock screen to remove shives.
This sequence avoids the need for dilution of the pulp for
screening and subsequent decker sewer losses.
b. Spill and Evaporator Boil-Out Storage
Evaporators are periodically "boiled out" to restore efficient
operation. The material flushed can be stored in a tank to be
slowly returned to the process upon resumption of operation.
Storage facilities can also be supplied to contain weak black
liquor, strong black liquor, and recovery plant chemicals and
liquors during process upsets for similar return to the system.
Sodium Base Neutral Sulfite Semi-Chemical (pulp mill only)
a. Pre-Refining Before Washing
This step should be accomplished in order to improve washing
efficiency.
b. Liquor Recovery
Liquor recovery can be accomplished by partial evaporation fol-
lowed by incineration in a fluidized bed reactor or other com-
parable unit.
153
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
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DRAFT
Ammonia Base Neutral Sulfite Semi-Chemical (pulp mill only)
a. Pre-Refining Before Washing
This step should be accomplished in order to improve washing
efficiency.
b. Non-Polluting Liquor Disposal
If there are operating problems in ammonia liquor incineration,
alternate methods for non-polluting disposal such as land dis-
posal where practicable, sale as a byproduct, etc., must be em-
ployed .
Kraft-Sodium Base Neutral Sulfite Semi-Chemical (pulp mill only)
a. Hot Stock Screening
As explained in Section VII, this is a process modification in
which the pulp is passed through a fibrilizer to fractionate
knots and then through a hot stock screen to remove shives.
This sequence avoids the need for dilution of the pulp for
screening and subsequent decker sewer losses.
b^ Spill and Evaporator Boil-Out Storage
Evaporators are periodically "boiled out" to restore efficient
operation. The material flushed can be stored in a tank to be
slowly returned to the process upon resumption of operation.
Storage facilities can also be supplied to contain weak black
liquor, strong black liquor, and recovery plant chemicals and
liquors during process upsets for similar return to the system.
Waste Paperboard
a. Land Disposal of Junk Materials
Extraneous matter found in waste paper, such as metals, plas-
tics, and rags, should be efficiently removed from the process
and disposed of on the land.
154
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
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Paper Machines (All subcategories)
a. Water Showers
Fresh water showers used to clean brine, felt, and other machine
elements (of both fourdrinier and cylinder machines) should be
low-volume and high-pressure; white water showers should be low-
pressure, high-volume, and self-cleaning.
b. Segregation of White Water Systems
The segregation of white water systems should be designed to per-
mit maximum reuse within the stock preparation/machine systems
and in the pulp mill and to permit only low fiber content white
water to enter the sewer.
c. Press Water Filtering
A vibrating or centrifugal screen should be employed to remove
felt hairs prior to press water reuse.
d. Collection System for Vacuum Pump Seal Water
Seal water should be collected for partial reuse and/or cascade
to or from other water users.
e. Save-all with Associated Equipment
An effective save-all should be employed to recover fibrous and
other suspended material which escapes from the paper machine.
f. Gland Water Reduction
Flow control of individual seal water lines to equipment packing
glands, or equivalent measures, should be exercised.
External Treatment
a. Suspended Solids Reduction
This step involves removal of suspended solids from the incoming
raw waste stream. It can incorporate either 1) an earthen
stilling basin; 2) mechanical clarification and sludge removal;
3) and/or dissolved air flotation. Solids dewatering screens
can also be incorporated prior to solids settling as a means of
removing coarse solids.
155
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
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DRAFT
b. BOD reduction
Biological oxidation is employed throughout the subject sub-
categories of mills. Two processes are used primarily, i.e.
1) high-rate activated sludge and 2) aerated stabilization
basins. Secondary support processes which can also be incor-
porated are 1) roughing filters and 2) natural oxidation
ponds following biological treatment.
c. Secondary solids removal
Where activated sludge is utilized for biological oxidation,
secondary mechanical clarification can be utilized for second-
ary solids removal. Stilling ponds can be incorporated after
aerated stabilization basins for removal of secondary solids.
Depending upon the design and configuration of the aerated basins,
a stilling pond can consist merely of a quiescent zone beyond the
influence of aeration equipment, but within the general confines
of the aerated basin itself.
d. Sludge disposal
When compatible with other unit processes, sludge disposal can
often be carried out in a stilling pond. However, this neces-
sitates periodic dredging, removal, and disposal of solids.
Where activated sludge and mechanical clarification are utilized,
ultimate sludge disposal can be accomplished through sludge
thickening by vacuum filtration or centrifugation, followed by
sludge dewatering and ultimate solids disposal. Disposal can be
accomplished by either land disposal or incineration. Combustion
of sludges can be carried either in a sludge incinerator, the
power boiler, or the bark boiler in unbleached kraft pulp mill
operations.
RATIONALE FOR THE SELECTION OF BEST POLLUTION CONTROL TECHNOLOGY CUR-
RENTLY AVAILABLE
Age and Size of Equipment and Facilities
There is a wide range, in both size and age, among mills in the subcate-
gories studied. However, internal operations of most older mills have
been upgraded, and some of these mills currently operate very efficient-
ly. The technology for upgrading of older mills is well established,
and does not vary significantly from mill to mill within a given sub-
category. Studies have also shown that waste treatment plant perfor-
mance does not relate to mill size. Most mills within a subcategory are
constructed on a "modular" concept, where key process elements are
156
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
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DRAFT
duplicated as mill size expands. Consequently, there is no significant
variation in either the waste water characteristics or in the waste
water loading rates, in kilograms per metric ton (in pounds per short
ton of product), between mills of varying sizes.
Process Change
Application of best technology currently available does not require
major changes in existing industrial processes for the subcategories
studied. Incorporation of additional systems, treatment processes, and
control measures can be accomplished in most cases through changes in
piping, and through design modifications to existing equipment. Such
alterations can be carried out on all mills within a given subcategory.
Engineering Aspects of Control Technique Applications
The technology to achieve these effluent limitations is practiced within
the subcategories under study. The concepts are proven, available for
implementation, and applicable to the wastes in questions. The waste
treatment techniques are also broadly applied within many other indus-
tries. The technology required will necessitate improved monitoring of
waste discharges and of waste treatment components on the part of many
mills,.as well as more extensive training of personnel on operation and
maintenance of waste treatment facilities. However, these procedures
are currently practiced in some mills and are common practice in many
other industries.
Non-water Quality Environmental Impact
Application of the activated sludge waste treatment process offers a
potential for adverse impact upon air quality if dewatered sludges are
incinerated. However, proper selection and operation of particulate
emission control equipment can minimize this impact. Dredged or dewa-
tered sludges disposed of on land can present an odor problem if a solid
waste disposal program is not properly implemented. Procedures are
available for its control which are utilized where applicable within
subcategories under study or in other industries. Methods for solution
of either of these problems do not create significant environmental im-
pacts.
The technology cited will not create any significant increase in noise
levels beyond those observed in well designed municipal wastewater treat-
ment systems which currently are being approved by the federal govern-
ment for construction in populated areas. Further, no hazardous chemi-
cals are required as part of this technology.
157
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
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DRAFT
The greatest proportion of energy consumed will be for pumping and for
biological treatment. The total energy requirements for implementation
of best available technology for the categories under study are not sub-
stantial and should not be sufficient enough to warrant concern on
either a national or regional basis. However, it should be cautioned
that no investigation has been made in this study on the cumulative
effect of energy requirements when all industries within the country
simultaneously implement best available technology levels.
Cost of Application in Relation to Effluent Reduction Benefits
Subcategory
Size-Short
Tons/Day
Total annual
cost, incl.
energy
Increase in
Production Costs
$/short ton
Unbleached Kraft 1000 $2,675,000
NSSC-Sodium Base 250 1,194,000
NSSC-Ammonia Base 250 375,000
7.65
13.65
4.30
Kraft-NSSC
(With Cross Rec.) 1000
Waste Paperboard
100
2,922,000
259,000
7.80
8.64
These increases reflect both all internal mill and external waste treat-
ment improvements. They are based on 350 days of production/year except
for the waste paperboard subcategory which is based upon 300 days/year.
It should be emphasized, however, that most mills have already carried
out many of these improvements. Subsequently, their increased costs
would be less than those shown above.
Processes Employed
All mills within each subcategory studied utilize the same basic produc-
tion processes. Although there are deviations in equipment and produc-
tion procedures, these deviations do not significantly alter either the
characteristics or the treatability of the wastewater generated.
158
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
-------
DRAFT
SECTION X
BEST AVAILABLE TECHNOLOGY
ECONOMICALLY ACHIEVABLE
INTRODUCTION
Best available technology economically achievable is to be achieved not
later than July 1, 1983. It is not based upon an average of the best
performance within a given subcategory under study, but has been deter-
mined by identifying the very best control and treatment technology em-
ployed by a specific point source within a given subcategory, or by
applying technology from other industry areas where it is transferr able.
Consideration was also given to:
a. the age of equipment and facilities involved;
b. the process employed;
c. the engineering aspects of the application of various types of
control techniques:
d. process changes;
e. cost of achieving the effluent reduction resulting from applica-
tion of the technology ;
f. non-water quality environmental impact, including energy require-
ments .
This level of technology emphasizes both internal process improvements
and external treatment of waste waters. It will, therefore, require
existing mills to implement significant internal changes on water reuse
and chemical recovery and recycle as well as to apply more advanced
waste treatment processes and other improved internal and external con-
trols in order to meet the suggested effluent guidelines. In some cases,
the industry may be required to conduct applied research and demonstra-
tion studies in order to firmly establish the most economical approach
toward meeting the guidelines. Such studies on the removal of color
and nitrogen, where applicable, will undoubtedly be desirable.
EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION OF BEST AVAILABLE
TECHNOLOGY ECONOMICALLY ACHIEVABLE
Based upon the information contained in Sections III through VIII of
this report, a determination has been made that the following point
159
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
-------
DRAFT
source discharge guidelines for each identified pollutant can be ob-
tained through the application of best available technology:
Recommended Effluent Guidelines,
Pounds per short Ton of Production
Subcategory BOD5 Suspended pH Range Color
Solids
Unbleached Kraft 2.0
NSSC-Sodium Base 3.5
NSSC-Ammonia Base 3.5
Kraft-NSSC
(With Cross Recovery) 3.5
Waste Paperboard 1.0
In addition, effluent limitation guidelines are recommended for nitro-
gen on NSSC ammonia base mills. However, no specific limitation has
been established because of the extreme restriction at this time on
meaningful data. Currently, only two such mills exist and preliminary
indications are that discharges in the range of 7.5-10.0 kilogram per
metric ton (15-20 pounds per short ton) can occur. No technology for
the removal of nitrogen has been applied within the pulp and paper in-
dustry, and only very limited technology has been applied in other in-
dustries, especially at the concentrations cited. Further, the allow-
able limitations are to a large degree dependent upon local conditions.
Extensive studies on effective methods for the removal of nitrogen must
be carried out as a means of establishing effluent limitations. Assum-
ing that adequate technology exists at the time, limitations of h pounds
per ton or less should be imposed.
The allowable pounds of BOD5 and suspended solids per ton of production
are to be based upon monthly averages of daily values as determined from
industrial records. It is expected that values on any given day could
exceed these guidelines. Further, values may be adjusted to reflect
variations in performance as a result of changes in materials mix, ambi-
ent air temperature, effect on waste treatment process performance, and
other local conditions.
Production capacity is defined as the total production off the machine,
including reprocessed broke. Daily production, in air-dry tons, is de-
fined as the highest average level sustained for seven consecutive
3.0 7.5-8.5 12.0
5.0 7.2-7.8 7.0
5.0 7.2-7.8 7.0
3.5 7.5-8.5 8.0
1.0 6.C-7.5 N/A
160
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
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DRAFT
operating days of normal production.
Values are intended to reflect the net pounds per ton of product which
are attributed to the industrial operation, and do not account for "back-
ground" pollutional loads which may have existed in the process water
prior to use by the industry.
IDENTIFICATION OF THE BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE
The best available technology economically achievable consists of the
best practicable control technology currently available as defined in
Section IX of this report. It also includes the following additional
internal mill improvements and external advanced waste water treatment
practices.
Internal Controls
Pulping operations of all applicable subcategories will be able to imple-
ment modifications and operating procedures for:
a. reuse of fresh water filter backwash;
b. control of spills whereby major pollutional loads bypass the
waste water treatment system to a retention basin and are ulti-
mately either reused, gradually discharged into the treatment
system, or treated separately;
c. reduction of pulp wash and extraction water;
d. intensive internal reuse of process waters;
e. separation of cooling waters from other waste water streams, and
subsequent heat removal and reuse;
f. intensive reduction of gland water spillage.
With the exception of the procedures pertaining to reuse of fresh water
filter backwash (a.) and reduction of pulp wash and extraction water
(c.), these same modifications and procedures are applicable to and ca-
pable of implementation by all paper machine systems, including waste
paperboard mills.
161
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
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DRAFT
External Treatment
Section IX of the report describes best practicable external control
technology currently available. Application of that technology in con-
junction with several additional recognized and potential technologies
described in Section VII constitutes best available technology econom-
ically achievable. The additional external processes applicable to this
more advanced technology are as follows:
a. suspended solids removal through either coagulation and floccu-
lation followed by settling, filtration, or reverse osmosis;
b. BOD^ reduction through the application of two-stage biological
treatment;
c. trace organics removal through either carbon adsorption or chlo-
rination;
d. color reduction by application of either lime precipitation or
carbon adsorption;
e. possible nitrogen reduction by use of either ion exchange, ni-
trification-denitrification in the biological process, or ammo-
nia stripping.
RATIONALE FOR THE SELECTION OF BEST AVAILABLE TECHNOLOGY ECONOMICALLY
ACHIEVABLE
Age and Size of Equipment and Facilities
There is a wide range, in both size and age, among mills in the subcate-
gories studied. However, internal operations of most older mills have
been upgraded, and some of these mills currently operate very efficient-
ly. The technology for upgrading of older mills is well established,
and does not vary significantly from mill to mill within a given sub-
category. Studies have also shown that waste treatment plant perfor-
mance does not relate to mill size. Most mills within a subcategory are
constructed on a "modular" concept, where key process elements are
duplicated as mill size expands. Consequently, there is no significant
variation in either the waste water characteristics or in the waste
water loading rates, in kilograms per metric ton (in pounds per short
ton of product), between mills of varying sizes.
162
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
-------
DRAFT
Process Changes
Application of best available technology economically achievable does
not require major changes in existing industrial processes for the sub-
categories studied. Incorporation of additional systems, treatment pro-
cesses, and control measures can be accomplished in most cases through
changes in piping, and through design modifications to existing equip-
ment. Such alterations can be carried out on all mills within a given
subcateory.
Engineering Aspects of Control Technique Applications
The technology to achieve most of these effluent limitations is either
practiced within the pulp and paper industry by an outstanding mill in a
given subcategory, or is demonstrated in other industries and is trans-
ferable. Possible exceptions are for color removal and nitrogen reduc-
tion. However, sufficient research and pilot work has been carried out
on both parameters to demonstrate the feasibility of achieving the
guidelines after completion of additional study. In fact, several full
scale color removal systems currently exist, and support the position
that color guidelines can ultimately be met. The technology required
for all best available treatment and control systems will necessitate
sophisticated monitoring, sampling, and control programs, as well as
properly trained personnel.
Non-water Quality Environmental Impact
Application of the activated sludge waste treatment process offers a
potential for adverse impact upon air quality if dewatered sludges are
incinerated. However, proper selection and operation of particulate
emission control equipment can minimize this impact. Dredged or dewa-
tered sludges disposed of on land can present an odor problem if a solid
waste disposal program is not properly implemented. Procedures are
available for its control which are utilized where applicable within
subcategories under study or in other industries. Methods for solution
of either of these problems do not create significant environmental im-
pacts .
The technology cited will not create any significant increase in noise
levels beyond those observed in well designed municipal wastewater treat-
ment systems which currently are being approved by the federal govern-
ment for construction in populated areas. Further, no hazardous chemi-
cals are required as part of this technology.
163
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
-------
DRAFT
The greatest proportion of energy consumed will be for pumping and for
biological treatment. The total energy requirements for implementation
of best available technology for the categories under study are not sub-
stantial and should not be sufficient enough to warrant concern on
either a national or regional basis. However, it should be cautioned
that no investigation has been made in this study on the cumulative
effect of energy requirements when all industries within the country
simultaneously implement best available technology levels.
Cost of Application in Relation to Effluent Reduction Benefits
Based upon the information contained in Section VIII of this report, to-
tal projected cost of upgrading a mill incorporating best practicable
control technology currently available to the level of best achievable
technology economically feasible reflects an increase in production ex-
penses as follows:
Subcategory
Size-Short
Tons/Day
Total annual
cost, incl.
energy
Increase in
Production cost
$/short ton
Unbleached Kraft 1000
NSSC-Sodium Base 250
NJ5SC-Ammonia Base 250
Kraft-NSSC 1000
(With Cross Recovery)
$1,501,000
557,000
558,000
1,646,000
4.30
6.36
6.36
4.70
Waste Paperboard
100
35,000
1.17
These increases reflect both all internal mill and external waste treat-
ment improvements, with the exception of nitrogen removal for NSSC ammo-
nia base mills. Sufficient data was not available on this parameter.
The increases are based on 350 days of production per year except for
the waste paperboard subcategory which is based upon 300 days per year.
Processes Employed
There is a wide range, in both size and age among mills in the subcate-
gories studied. However, internal operations of most older mills have
been upgraded, and some of these mills currently operate very efficient-
ly. The technology for upgrading of older mills is well established,
and does not vary significantly from mill to mill within a given sub-
category. Studies have also shown that waste treatment plant perfor-
mance does not relate to mill size. Most mills within a subcategory are
164
NOTICE; THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
-------
DRAFT
constructed on a "modular" concept, where key process elements are
duplicated as mill size expands. Consequently, there is no significant
variation in either the waste water characteristics or in the waste
water loading rates, in kilograms per metric ton (in pounds per short
ton of product), between mills of varying sizes.
165
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
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DRAFT
SECTION XI
NEW SOURCE PERFORMANCE STANDARDS
INTRODUCTION
This level of technology Is to be achieved by new sources. The term
"new source" Is defined in the Act to mean "any source, the construction
of which is commenced after the publication of proposed regulations pre-
scribing a standard of performance." Such commencement of construction
can occur within the near future, certainly before either the 1977 or
1983 compliance dates for either best practicable or best achievable
technologies. Therefore, new source performance standards utilize best
practicable control technology currently available as a base, but also
encompass additional treatment and control technologies through the
application of improved production processes which are designed to reduce
pollutant loads.
Consideration has also been given to:
a. The type of process employed and process changes;
b. Operating methods;
c. Batch as opposed to continuous operations;
d. Use of alternative raw materials and mixes of raw materials;
e. Use of dry rather than wet processes (Including substitution
of recoverable solvents for water);
f. Recovery of pollutants as by-products;
g. Pre-treatment requirements for discharges to municipal systems.
EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION OF NEW SOURCE
PERFORMANCE STANDARDS
Based upon the information contained in Sections III through VII of this
report, a determination has been made that the following point source
discharge standards for each identified pollutant can be obtained through
the application of proper technology:
167
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA,
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OR AFT
RECOMMENDED NEW SOURCE STANDARDS OF PERFORMANCE
Pounds Per Short Ton Of Production
Subcategory
BODs
Suspended Solids pH Ranee
Color
Unbleached Kraft
3.5
5.0
7.5-8.5
25.0
NSSC-Sodium Base
5.0
6.0
7.2-7.8
20.0
NSSC-Ammonia Base
5.0
6.0
7.2-7.8
20.0
Kraft-NSSC (Cr. Rec.)
4.5
6.0
7.5-8.5
22.0
Waste Paperboard
1.5
1.5
6.0-7.5
N/A
In addition, performance standards are recommended for nitrogen
on NSSC-ammonla base mills. However, no specific limitation has been
established because of the extreme restriction at this time on meaning-
ful data. Currently, only two such mills exist and preliminary indica-
tions are that discharges in the range of 7.5-10.0 kilograms per metric ton
(15-20 pounds per short ton) can occur. No technology for the removal
of nitrogen has been applied within the pulp and paper industry, and
only very limited technology has been applied in other Industries,
especially at the concentrations cited. Further, the allowable limita-
tions are to a large degree dependent upon local conditions. Extensive
studies on effective methods for the removal of nitrogen must be carried
out as a means of establishing effluent limitations. Assuming adequate
technology exists at the time, limitations of 4.0-6.0 kilograms per me-
tric ton (eight-12 pounds per short ton) or less should be imposed.
The allowable pounds of BOD5 and suspended solids per ton of production
are to be based upon monthly averages of dally values as determined
from industrial records. It is expected that values on any given day
could exceed these guidelines. Further, values may be adjusted to
reflect variations in performance as a result of changes in materials
mix, ambient air temperature effect on waste treatment process performed,
and other local conditions.
Production capacity is defined as the total production off the machine,
including reprocessed broke. Daily production, in air dry tons, is de-
fined as the highest average level sustained for seven consecutive opera-
ting days of normal production.
Values are intended to reflect the net pounds per ton of product which
are attributed to the industrial operation, and do not account for
"background" pollutional loads which may have existed In the process
water prior to use by the industry.
168
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
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DRAFT
IDENTIFICATION OF TECHNOLOGY FOR NEW SOURCE PERFORMANCE STANDARDS
The technology available for new source performance standards consists
of the best practicable control technology currently available as de-
fined in Section IX of this report. It also Includes limited application
of additional internal mill Improvements and external advanced waste
water treatment practices as defined in Section X of this report for
best available technology economically achievable.
It is expected that "new source" mills will not be able to realize
maximum efficiency in the limited application of best available tech-
nology economically achievable since additional study is required before
the full potentials of some of the technologies can be identified.
However, "new source" mills have an advantage over existing mills in
areas of recovery, recycle, reuse, and spill control. These improvements
can be more readily incorporated into new mill designs than into existing
mills which must be modified.
rationale for selection of technology for new source performance
STANDARDS
Type of Process Employed and Process Changes
No radical new ln-plant processes are proposed as a means of achieving
new source performance standards for the subcategories studied. Similar-
ly, the changes which may be required within existing industrial pro-
cesses will only necessitate changes in piping, addition of monitoring
and control systems, and other minor changes.
Operating Methods
Significant revisions in operating methods, both in-plant and at the
waste water treatment facility, will be necessary. However, these im-
provements are not beyond the scope of well-trained personnel, and are
currently being practiced in other Industries. The primary areas of
operational change will pertain to required activities for recycle, re-
use, and spill control, as well as for optimal performance of waste
water treatment facilities.
Batch as Opposed to Continuous Operations
For the subcategories studied, it was determined that batch as opposed
to continuous operations are not a significant factor in waste load
characteristics and no additional control of pollutants could be achieved
through the use of one type process over the other.
169
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
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DRAFT
Use of Alternative Raw Materials and Mixes of Raw Materials
The raw materials requirements for a given mill in each of the subcate-
gories studied do vary, depending upon supply and demand, desired end
product, and other conditions. However, alteration of raw materials as
a means of reducing pollutants is not considered feasible over the long
term even though such a change could possibly realize benefits of short
duration in a given instance. The one possible exception to this could
be alternatives for the NSSC-ammonia base mill if an effective and
economical method for removal of nitrogen does not become available
through further study.
Use of Dry Rather than Wet Processes (Including Substitution of
Recoverable Solvents for Water)
For the subcategories studied, It was determined that technology for dry
pulping or papermaking processes does not exist nor is it in a suffi-
ciently viable experimental stage to be considered here.
Recovery of Pollutants as Byproducts
As discussed In Section VIII of this report, recovery of some potentially
polluting materials as byproducts Is economically feasible and commonly
practiced in unbleached kraft mills. In addition, ash from incineration
of sodium base NSSC spent liquor is sold to kraft mills to be used as
make-up chemical which avoids the necessity for Its disposal. It Is
anticipated that these performance standards will motivate increased
research on recovering other materials for byproduct sale the recovery
of which is not presently economically feasible.
Pre-treatment Requirements for Discharges to Municipal Systems
None of the pollutant parameters identified in Section VI of this report,
with the possible exception of nitrogen and pH, can be expected to dis-
rupt or interfere with the normal operation of a municipal waste water
treatment system which is designed to accommodate the industrial pollu-
tant load discharged to it from any mill within the subcategories
studied. In the case of pH, some pre-treatment may be required if it
can be shown that the normal pH range in the waste discharged from a
given mill exceeds 6-8.5. For nitrogen, pre-treatment will be necessary
if the levels discharged will disrupt any biological process being em-
ployed .
170
NOTICE: THESE ARE TENTATIVE RECOMMENDATIONS BASED UPON^IN-
FORMATION IN THIS REPORT AND ARE SUBJECT TO CHANGE BASED
UPON COMMENTS RECEIVED AND FURTHER INTERNAL REVIEW BY EPA
-------
SECTION XII
ACKNOWLEDGEMENTS
WAPORA, Inc., and its subcontractors, E. C. Jordan Co. and EKONO, grate-
fully acknowledge the assistance and guidance of the Effluent Guidelines
Division of EPA throughout all phases of the work which culminate in this
report. Appreciation is also extended to companies who granted access
to their mills and treatment works for field surveys and for the assistance
lent by mill personnel to field crews. The operating records furnished
by these manufacturers and information supplied by other individuals in
the industry contributed significantly to the project. The cooperation
of the National Council for Air and Stream Improvement in providing
liaison with the industry was an invaluable asset, and this service is
greatly appreciated. Thanks are also extended to the American Paper
Institute for its continued assistance.
171
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1
2
3
4
5
6
7
8
9
10
11
12
13
14
SECTION XIII
REFERENCES
Casey, J. P., Pulp and Paper, Chemistry and Chemical Technology,
Vol. I Pulping and Bleaching, 2nd Ed., Interscience Publishers,
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Pulp and Paper Manufacture, Vol. I: The Pulping of Wood, 2nd Ed.,
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Brown, R. W. , et. al., "Semi-Chemical Recovery Processes and
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Paper, Paperboard, Wood Pulp Capacity, 1971-1974, American Paper
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Axelsson, 0., "Some Views on Brown Stock Washing," International
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Chemical Recovery in the Alkaline Pulping Processes, TAPPI
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Gehm, H. W., State~of-the~Art Review of Pulp and Paper Waste
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Rydholm, S. A., Pulping Processes, Interscience Publishers, New
York (1965).
Bryan, W. P., "inland's Tennessee Mill Was First Designed for
Ammonia Base NSSC," Paper Trade Journal, Sept. 25 (1972).
Moore, J. L., "Ammonia Base Sulphite Pulping at Inland Container,"
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Pulp and Paper Manufacture, Vol. II: Control, Secondary Fiber
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Britt, K.W., Handbook of Pulp and Paper Technology, 2nd Ed., Van
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173
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15. Kleppe, P. J., and Rogers, C. N., Survey of Water Utilization and
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16. Private Communication (1970).
17. Kronis, H., and Holder, D. A., "Drum Barker Effluent," Pulp and
Paper Magazine of Canada, 69, 62 Feb. (1968).
18. Draper, R. E., and Mercier, F. S., "Hydraulic Barker Effluent
Clarifier at Woods Products Division, Weyerhaeuser Co.," Proceed-
ings 11th Pacific Northwest Industrial Waste Conf. (1962).
19. Blosser, R. 0., "Practice in Handling Barker Effluents in Mills in
the United States," NCASI Technical Bulletin No. 194 (1966).
20. Pollutional Effects of Pulp and Papermill Wastes in Puget Sound,
FWQA, U.S. Dept. of the Interior (1967).
21. Lowe, K. E., "Control of Effluent at a NSSC Mill by Reuse of White
Water," TAPPI 7th Water and Air Conf. (1970).
22. Vilbrant, F., "Report on Semi-Chemical Wastes," NCASI Technical
Bulletin No. 28 (1949).
23. Nelson, W. R., et. al., "Process Water Reuse and Upset Control
Modifications at an Integrated NSSC Mill," TAPPI Environmental
Conference (1973).
24. South, W. D., "New Approaches to In-Plant Land Control and Monitor-
ing," NCASI Technical Bulletin No. 248, Part II, 2 (1971).
25. Wilson, D. F., Johanson, L. N., and Hrutfiord, B. F., "Methanal,
Ethanal, and Acetone in Kraft Pulp Mill Condensate Streams,"
TAPPI 55, 8 (1972).
26. Estridge, R. B., Thibodeaux, L. J., et. al., "Treatment of Selected
Kraft Mill Wastes in a Cooling Tower," TAPPI 7th Water and Air
Conf. (1970)
27. Bergkvist, S., and Foss, E., "Treatment of Contaminated Condensates
in Kraft Pulp Mills, "international Congress on Industrial Waste
Water, Stockholm (1970).
28. Haynes, D. C., "Water Reuse — A Survey of the Pulp and Paper
Industry." TAPPI, 49, 9 (1966).
174
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29. Standard Methods for the Examination of Water and Wastewater,
APHA, AWWA, and WPCF, American Public Health Assoc., Inc.,
New York (1971).
30. Michigan Water Resources Commission, "Reports on Kalamazoo River."
31. Wisconsin State Department of Health, Pulp and Paper Advisory
Committee Report (1965).
32. Bishop, F.W., et al., "Biological Waste Treatment Case Histories
in the Pulp and Paper Industry," NCASI Technical Bulletin No. 220
(1968).
33. Timpe, W.G., Lang, E., and Miller, R.L., Kraft Pulping Effluent
Treatment and Reuse - State of the Art, Environmental Protection
Technology Series EPA-R2-73-164 (1973).
34. Hrutfiord, B.F., el al., Steam Stripping Odorous Substances from
Kraft Effluent Streams, EPA-R2-73-196, April (1973).
35. Matteson, M.J. , et al., "SEKOR II: Steam Stripping of Volatile
Organic Substances from Kraft Pulp Mill Effluent Streams,"
TAPPI 50, 2 (1967).
36. Maahs, H.G., et al., "SEKOR III: Preliminary Engineering Design
and Cost Estimates for Steam Stripping Kraft Pulp Mill Effluents,"
TAPPI 50, 6 (1967).
•j ,,
37. Nelson, W. R., and Walraven, G. 0., A Role for Reverse Osmosis
in a Neutral Sulfite Semichemical Pulp and Paperboard Mill,"
Purdue University Industrial Waste Conf. XXIII (1968).
38. Morris, D. C., Nelson, W. R., and Walraven, G. O., "Recycle of
Papermill Waste Waters and Application of Reverse Osmosis,"
0RM, EPA Program #12040 FUB, Jan. (1972).
39. Associated Water and Air Resources Engineers, Inc., Waste
Characterization and Treatment Evaluation of an Ammonia-Laden
Pulp and Paper Mill Waste, Prepared for Inland Container Corp.,
Dec. (1971).
40. Gould, M., and Walzer, J., "Mill Waste Treatment by Flotation."
41. Follett, R., and Gehm, H. W., "Manual of Practice for Sludge
Handling in the Pulp and Paper Industry," NCASI Technical
Bulletin No. 190 (1966.
42. Edde, H., "A Manual of Practice for Biological Waste Treatment
in the Pulp and Paper Industry," NCASI Technical Bulletin No. 214
(1968) .
175
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43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
DRAFT
Gellman, I., "Aerated Stabilization Basin Treatment of Mill
Effluents," NCASI Technical Bulletin No. 185 (1965).
Sludge Dewatering, Manual of Practice No. 20, FWPCA (1969).
Gehm, H. W., "Effects of Paper Mill Wastes on Sewage Treatment
Plant Operation," Sewage Works Journal, 17,.510 (1945).
Lindsey, A. M., "Dewatering Paper Mill Sludges by vaccum Filtra-
tion," Purdue Univ. Industrial Waste Conf. XXIII (1968).
Voegler, J., "Drainability and Dewatering of White Water Sludges,"
NCASI Technical Bulletin No. 35 (1950).
Stovall, J. H., and Berry, D. A., "Pressing and Incineration of
Kraft Mill Primary Clarifier Sludge," TAPPI 6th Water and Air
Conf. (1969).
Aspitarte, T. R., et. al., "Pulp and Paper Mill Sludge Utilization
and Disposal," TAPPI Environmental Conf. (1973),
Coogan, F. J., and Stovall, J. H., "incineration of Sludge from
Kraft Pulp Mill Effluents," NCASI Technical Bulletin No. 185
(1965).
Bishop, F. W., and Drew, A. E., "Disposal of Hydrous Sludges
from a Paper Mill," TAPPI Water and Air Conf. (1971).
Harkin, J. M., and Crawford, D. L., "Bacterial Protein from Paper
Mill Sludges," TAPPI Environmental Conf. (1973).
Gellman, I., "Reduction of Paper, Paperboard and Weak Pulping
Wastes by Irrigation," Pulp and Paper Magazine of Canada, T-221,
March (1960).
Vercher, B. D., et. al., "Paper Mill Waste Water for Crop
Irrigation and Its Effects on the Soil," Louisiana State Univ.,
Agricultural Experiment Station Bulletin No. 604 (1965).
Voights, D., "Lagooning and Spray Disposal of NSSC Pulp Mill
Liquors," Purdue Univ. Industrial Waste Conf. X (1955).
Berger, H. F., "Development of an Effective Technology for Pulp
and Bleaching Effluent Color Reduction," NCASI Technical Bulletin
No. 228 (1969). ,
Spruill, E. L., Draft of final report, Color Removal and Sludge
Disposal Process for Kraft Mill Effluents, EPA Project #12040
DRY (1973) .
176
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58. Moggio, W. A., "Experimental Chemical Treatments For Kraft Mill
Wastes," NCSI Technical Bulletin No. 50 (1952).
59. "Treatment of Calcium-Organic Sludges Obtained From Lime Treatment
of Kraft Pulp Mill Effluents - Part I," NCSI Technical Bulletin
No. 62 (1955).
60. "Treatment of Calcium-Organic Sludges from Lime Treatment of Kraft
Pulp Mill Effluents - Part II," NCSI Technical Bulletin No. 75
(1955).
61. "Development Studies on the Removal of Color from Caustic Extract
Bleaching Effluent By the Surface Reaction Process - Part I,"
NCSI Technical Bulletin No. 107 (1958).
62. Berger, H. F., and Brown, R. I., "The Surface Reaction Method for
Color Removal From Kraft Bleachery Effluents," NCSI Technical
Bulletin No. 119 (1&59).
63. "Development Studies on the Removal of Color from Caustic Extract
Bleaching Effluent by the Surface Reaction Process - Part II,"
NCSI Technical Bulletin No. 122 (1959).
64. Herbert, A. J., "A Process for Removal of Color from Bleached
Kraft Effluents Through Modification of the Chemical Recovery
System," NCSI Technical Bulletin No. 157 (1962). U.S. Patent
#3,120,464.
65. Oswalt, J. L., and Lund, J. G., Jr., Color Removal from Kraft
Pulp Mill Effluents by Massive Lime Treatment, EPA Project 12040
DYD (1973) .
6'5. Davis, C. L., Color Removal from Kraft Pulping Effluent by Lime
Addition, Interstate Paper Corporation, EPA Project 12040 ENC
(1971) .
67. Spruill, E. L., Color Removal and Sludge Recovery from Total.Mill
Effluent. Paper presented at TAPPI Environmental Conference,
Houston, Texas (1972).
68- Smith, D. R., and Berger, H. F., "waste Water Renovation," TAPPI
51 (1968).
69. Berger, H. F., and Thibodeaux, L. J., "Laboratory and Pilot Plaht
Studies of Water Reclamation," NCASI Technical Bulletin No. 203
(1967).
70. McGlasson, W. G., et. al., "Treatment of Pulp Mill Effluents With
Activated Carbon," NCSI Technical Bulletin No. 199 (1967).
177
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draft
71. Smith, S. E., and Christman, R. F., "Coagulation of Pulping
Wastes for the Removal of Color," Journal of the Water Pollution
Control Federation, V. 41, No. 2, Part I (1969).
72. Middlebrooks, E. J., et. al, "Chemical Coagulation of Kraft Mill
Wastewater," Water and Sewage Works, V. 116, No. 3 (1967).
73.. Timpe, W. G., and Lang, E. W., "Activated Carbon Treatment of
Unbleached Kraft Effluent for Reuse, Pilot Plant Studies," TAPPI
Environmental Conference (1973).
74. Private Communication, St. Regis Paper Company, 1973.
75. Leitner, Gordon F., "Reverse Osmosis For Waste Water Treatment -
What? When?, TAPPI 8th Water & Air Conference (1971).
76. Wiley, A. J., Dubey, G. A., and Bansal, J. K., Reverse Osmosis
Concentration of Dilute Pulp and Paper Effluents, The Pulp Manu-
facturers Research League and The Institute of Paper Chemistry
for EPA, Project #12040 EEL, Feb (1972).
77. Johnson, J. S., Jr., Minturn, R. E., and Moore, G. E., Hyper-
filtration (Reverse Osmosis) of Kraft Pulp Mill and Bleach Wastes,
Chemistry Division, Oak Ridge National Laboratory (unpublished)
(1973) .
78. Beder, H., and Gillespie, W. J., "The Removal of Solutes From
Pulp Mill Effluents by Reverse Osmosis," TAPPI 53, 5 (1970).
79- Smith, R., and McMichael, W. F., Cost and Performance Estimates
For Tertiary Wastewater Treatment Processes, Federal Water Pol-
lution Control Administration, June (1969).
80. Bishop, H. K., Use of Improved Membranes in Tertiary Treatment by
Reverse Osmosis, McDonnell Douglas Astronautics Company for EPA,
Program #17020 DHR, Dec. (1970).
81. Kreusch, E., and Schmidt, K., Wastewater Demineralization by Ion
Exchange," Culligan International Co. for the EPA, Project
#17040 EEE, Dec (1971).
82. Linstedt, K. D., Houck, C. P., and O'Connor, J. T., "Trace Element
Removals in Advanced Wastewater Treatment Processes," Journal of
the Water Pollution Control Federation, 43, 7, July (1971).
83. Gregory, J., and phond, R. V., "wastewater Treatment by Ion
Exchange," Water Research (Great Britain), Pergamon Press (1973).
84. Eckenfelder, W. W., Jr., Krenkel, P. A., and Adams, C. A.,
Advanced Waste Water Treatment, American Institute of Chemical
Engineers, New York (1972).
178
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85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
DRAFT
Hansen, S. P., and Burgess, F. J., "Carbon Treatment of Kraft
Condensate Wastes," TAPPI, 51, 6 (1968).
Rimer, A. E., et. al., "Activated Carbon System For Treatment of
Combined Municipal and paper Mill Waste Waters in Fitchburg,
Mass., TAPPI, 54, 9 (1971).
Smith, D. R., and Berger, H. F., "Waste Water Renovation," TAPPI,
51, 10 (1968).
Timpe, W. G., et al., "The Use of Activated Carbon For Water
Renovation In Kraft Pulp and Paper Mills," Seventh TAPPI Water
and Air Conf. (1970).
Coates, J., and McGlasson, W. G., "Treatment of Pulp Mill
Effluents With Activitated Carbon," NCASI Technical Bulletin No.
199 (1967) .
Davies, D. S., and Kaplan, R. A., "Activated Carbon Eliminates
Organics," Chemical Engineering Progress, 60, 12 (1964).
Bishop, D. F., et al., "Studies on Activated Carbon Treatment,"
Journal WPCF, 39, 2 (1967).
Vanier, C., et. al, Carbon Column Operation in Waste Water Treat-
ment, Syracuse University, Syracuse, New York, Nov. (1970).
Weber, W. J., Jr., and Morris, J. C., "Kinetics of Adsorption in
Columns of Fluidized Media," Journal WPCF, 37, 4 (1965).
Beebe, R. L. , and Stevens, J. I., "Activated Carbon System for
Wastewater Renovation," Water and Wastes Engineering, Jan. (1967).
Culp, R. L., and Culp, G. L., Advanced Waste Treatment, Van
Nostrand Reinhold, New York (1971).
Holm, J. D., "A Study of Treated Wastewater Chlorination," Water
and Sewage Works, April (1973).
Meiners, A. F., Light-Catalyzed Chlorine Oxidation For Treatment
of Wastewater, Midwest Research Institute, for Water Quality
Office, EPA, Sept. (1970).
Huibers, T. A., et. al., Ozone Treatment of Secondary Effluents
From Wastewater Treatment Plants, Robert A. Taft Water Research
Center Report No. TWRC-4, April (1969).
Chen, J. w., and Smith, G. V. , Feasibility Studies of Applications
of Catalytic Oxidation in Wastewater, Environmental Protection
Agency, Southern Illinois University, for EPA, Nov. (1971).
179
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100
101
102
103
104
105
106
107
108
109
110
111
Optimization of Ammonia Removal by Ion Exchange Using Clinoptilo-
lite, University of California for EPA, Project #17080 DAP,
Sept. (1971).
Wastewater Ammonia Removal by Ion Exchange, Battelle - Northwest
for EPA, Project #17010 EEZ, Feb. (1971).
Johnson, Walter K., and Vania, George B., Nitrification and
Denitrification of Waste Water, University of Minnesota for
EPA, Research Grant Number WP 01028, Jan. (1971).
Nitrogen Removal From Wastewaters, Federal Water Quality Research
Laboratory, Advanced Waste Treatment Research Laboratory,
Cincinnati, Ohio, Oct. (1970).
Shindala, Adnan, "Nitrogen and Phosphorus Removal From Waste-
waters - Part I," Water and Sewage Works, June (1971).
Shindala, Adnan, "Nitrogen and Phosphorus Removal From Waste-
waters - Part II," Water and Sewage Works, July (1971).
Hendrickson, E. R. , et al., Control of Atmospheric Emissions in
the Wood Pulping Industry, DHEW, NAPCA Contract No. CPA 22-69-18,
Mar. (1970).
Drew, J., and Pyland, G. D., Jr., "Turpentine from the Pulpwoods
of the United States and Canada," TAPPI 49, 10 (1966).
Resource Engineering Associates, "State of the Art Review on
Product Recovery," FWPCA Contract No. 14-12-495, Nov. (1969).
Ellenbe, R. W., "Why, Where and How U.S. Mills Recover Tall Oil
Soap," Paper Trade Journal, June 25 (1973).
Barton, J. S., "Future Technical Needs and Trends of the Paper
Industry, By-Products Usages," TAPPI 56, 6 (1973).
"Availability of Construction Manpower," Engineering News Record,
June 7 (1973).
180
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DRAFT
SECTION XIV
GLOSSARY
Act
Federal Water Pollution Control Act, as amended in 1972.
Air Dry Ton
Measurement of production including moisture content, which usually
varies between four and ten percent.
Bark
The protective covering of a tree.
Barking
Removal of bark from logs in a wet or dry process.
Black Liquor
Spent liquor recovered from a kraft digester up to the point of its
incineration in the recovery plant.
Bleaching
The brightening and delignification of pulp by addition of chemicals
such as chlorine.
Boil-Out
A procedure, usually utilizing heat and chemicals, to clean process
equipment such as evaporators, heat~exchangers and pipelines.
Broke
Partly or completely manufactured paper that does not leave the machine
room as salable paper or board; also paper damaged in finishing opera-
tions such as rewinding rolls, cutting, and trimming.
Cellulose
The fibrous constituent of trees which is the principal raw material
of paper and paperboard.
181
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r"; H;- f^V
Chemi-Mechanical Pulp
Pulp produced mechanically by grinding or refining after presoaking of
wood with caustic soda/sodium sulfite solution.
Chest
A tank used for storage of wet fiber or furnish.
Chips
Small pieces of wood used to make pulp.
Coatings
Materials such as clay, starch, alum, synthetic adhesives, etc., applied
to the surface of paper or paperboard to impart special characteristics.
Color Unit
A measure of color concentration in water using APHA methods.
Consistency
The weight percent of solids in a solids-water mixture used in the
manufacture of pulp or paper.
Cooking
Heating of wood, water, and chemicals in a closed vessel under pressure
to a temperature sufficient to separate fibrous portion of-wood by dis-
solving lignin and other nonfibrous constituents.
Cooking Liquor
The mixture of chemicals and water used to dissolve lignin in wood
chips.
Countercurrent Washing
I
Pulp washing in which fresh water is added only at the last stage and
the effluent from this stage is then used as wash water for the previous
stages .
Decker
A mechanical device used to remove water or spent cooking liquor from
pulp.
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Digester
A pressure vessel used to cook wood chips in the presence of cooking
liquor and heat.
Dregs
The inert rejects from the chemical recovery process of pulp mill.
External Treatment
Technology applied to raw waste streams to reduce pollutant levels.
Extraction Water
Water removed during a pulp manufacturing process.
Felt
An endless belt of wool or plastic
during the papermaking process
Fiber
used to convey and dewator the sheet
The cellulosic portion of the tree used to make pulp, paper and paper-
board .
Furnish
The mixture of fibers and chemicals used to manufacture paper.
Gland
A device utilizing a soft wear resistant material used to minimize
leakage between a rotating shaft and the stationary portion of a
vessel such as a pump
Gland Water
Water used to lubricate a gland. Sometimes called "packing water."
Grade
The type of pulp or paper product manufactured.
Green Liquor
Liquor made by dissolving chemicals recovered from the kraft process
in water and weak liquor preparatory to causticizing.
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p~>, r>
f- y-
In Plant Measures
Technology applied within the manufacturing process to reduce or
eliminate pollutant in the raw waste water. Sometimes called .
"internal measures."
Level I
Best practicable control technology .
Level II
Best available technology economically achievable.
Level III
New source performance standards.
Lignin
The chemically complex dark-colored portion of tree used in nature
to bind the cellulose fibers together.
Packing Water
See Gland water.
Pulp
Cellulosic fibers after conversion from wood chips.
Pulper
A mechanical device resembling a large-scale kitchen blender used to
separate fiber bundles in the presence of water prior to papermaking
Re.jects
Material unsuitable for pulp or papermaking which has been separated
in the manufacturing process.
Save-all
A mechanical device used to recover papermaking fibers and other
suspended solids from a waste water or process stream.
Screenings
Rejects from a pulp mill separating device such as a screen.
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Sheet
The web of paper or paperboard as manufactured on a paper machihe.
Spent Cooking Liquor
Cooking liquor after the digesting operation, containing lignaceous as
well as chemical materials.
Stock
Wet pulp with or without chemical additions.
Suction Box
A rectangular box with holes or slots on its top surface, used to suck
water out of a felt or paper sheet by the application of vacuum.
Suction Couch Roll
A rotating roll containing holes through which water is sucked out of
a paper sheet on a fourdrinier machine, by the application of vacuum.
Sulfidity
In kraft pulping, the percentage ratio of Na2S, expressed as Na20, to
active alkali.
Virgin Wood Pulp (or fiber)
Pulp made from wood, as contrasted to waste paper sources of fiber.
White Liquor
Liquors made by causticizing green liquors; cooking liquor.
White Water
Water which drains through the wires of a paper machine which contains
fiber, filler, and chemicals.
Wire
An endless moving belt made of metal or plastic, resembling a window
screen, upon which a sheet of paper is formed on a fourdrinier machine.
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APPENDIX 1
MILLS WHICH EXEMPLIFY PHASE I SUBCATEGORIES
Unbleached Kraft Mills
Unljax, Inc.
Elizabeth, Louisiana
Pineville Kraft Corp.
Pineville, Louisiana
Georgia Kraft Co.
Mahrt, Alabama
Union Camp Corp.
Montgomery, Alabama
MacMillan Bloedel United, Inc.
Pine Hill, Alabama
Crown Zellerbach Corp.
St. Francisville, Louisiana
Gulf States Paper Corp.
Tuscaloosa, Alabama
International Paper Co.
Camden, Arkansas
Arkansas Kraft Corp.
Morrilton, Arkansas
Weyerhaeuser Co.
Pine Bluff, Arkansas .
Container Corp. of America
Femandlna Beach, Florida
Alton Box Board Co.
Jacksonville, Florida
St. Regis Paper Co.
Jacksonville, Florida
Georgia Kraft Co.
Krannert, Georgia
St. Regis Paper Co.
Montlcello, Mississippi
International Paper Co.
Vicksburg, Mississippi
Albemarle Paper Co.
Roanoke Rapids, North Carolina
International Paper Co.
Gardiner, Oregon
Weyerhaeuser Co.
Springfield, Oregon
Georgia-Pacific Corp.
Toledo, Oregon
Tennessee River Pulp and Paper Co
Counce, Tennessee
Owens-Illinois, Inc.
Orange, Texas
Georgia Kraft Co.
Macon, Georgia
Continental Can Co., Inc.
Port Wentvorth, Georgia
Interstate Paper Corp.
Riceboro, Georgia
Owens-Illinois, Inc.
Valdosta, Georgia
Westvaco Corp.
Charleston, South Carolina
South Carolina Industries, Inc.
Florence, South Carolina
Crown Zellerbach Corp.
Port Townsend, Washington
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APPENDIX 1. Contd.
NSSC-Kraft Mills
Great Northern Paper Co.
Olinkraft, Inc.
Cedar Springs, Georgia
West Monroe, Louisiana
Union Camp Corp.
Weyerhaeuser Co.
Savannah, Georgia
Valliant, Oklahoma
International Paper Co.
Western Kraft Corp.
Bastrop, Louisiana
Albany, Oregon
Continental Can Co.
Boise Cascade Corp.
Hodge, Louisiana
Wallula, Washington
NSSC Mills
(Sodium Base)
Weston Paper and Manufacturing Co.
Container Corp.
Terre Haute, Indiana
Circlevllle, Ohio
Celotex Corp.
Stone Container Corp.
Dubuque, Iowa
Coshocton, Ohio
Consolidated Packaging Corp.
Celotex Corp.
Fort Madison, Iowa
Sunbury, Pennsylvania
Wescor Corp.
Mead Corp.
Hawesville, Kentucky
Harriman, Tennessee
Hoerner Waldorf Corp.
Temple Industries, Inc.
Ontonagon, Michigan
Dlboll, Texas
Menasha Corp.
Owens-Illinois, Inc.
Otsego, Michigan
Big Island, Virginia
Hoerner Waldorf Corp.
Mead Corp.
St. Paul, Minnesota
Lynchburg, Virginia
Groveton Papers Co.
Green Bay Packaging, Inc.
Groveton, New Hampshire
Green Bay, Wisconsin
Georgia-Pacific Corp.
Owens-Illinois, Inc.
Lyons Falls, New York
Tomahawk, Wisconsin
Georgia-Pacific Corp.
Plattsburgh, New York
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APPENDIX 1 . Contd.
NSSC Mills (Ammonia Base)
Mead Corp.
Sylva, North Carolina
Inland Container Corp.
New Johnsonville. Tennessee
Waste Paperboard Mills In the U.S.
National Gypsum Co. Colonial Board Co.
Annlston, Alabama Manchester, Connecticut
Stone Container Corp.
Mobile, Alabama
Sonoco Products Co.
City of Industry, California
Federal Paper Board Co.
Los Angeles, California
L.A. Paper Box & Board Mills
Los Angeles, California
Sonoco Products Co.
Richmond, California
Kaiser Gypsum Co.
San Leandro, California
Container Corp. of America
Santa Clara, California
Georgia-Pacific Corp.
Santa Clara, California
U.S. Gypsum Co.
South Gate, California
Flbreboard Corp.
Stockton, California
Flberboard Corp.
Vernon, California
Robertson Paper Box Co.
Montville, Connecticut
Federal Paper Board Co.
New Haven, Connecticut
Simklns Industries, Inc.
New Haven, Connecticut
Federal Paper Board Co.
Versailles, Connecticut
Container Corp. of America
Wilmington, Delaware
U.S. Gypsum Co.
Jacksonville, Florida
Simklns Industries, Inc.
Miami, Florida
Sonoco Products Co.
Atlanta, Georgia
Austell Box Board Corp.
Austell, Georgia
Alton Box Board Co.
Cedartovn, Georgia
Alton Box Board Co.
Alton, Illinois
Packaging Corp. of America
Denver, Colorado
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APPENDIX 1 , Contd.
Waste Paperboard Mills in the U.S.,
Container Corp. of America
Chicago, Illinois
Prairie State Paper Mills
Joliet, Illinois
Nabisco, Inc.
Marseilles, Illinois
Federal Paper Board Co.
Morris, Illinois
Quaker Oats Co.
Pekin, Illinois
Packaging Corp. of America
Quincy, Illinois
Sonoco Products Co.
Rockton, Illinois
Kleffer Paper Mills, Inc.
Brownstown, Indiana
Container Corp. of America
Carthage, Indiana
Beveridge Paper Co.
Indianapolis, Indiana
Alton Box Board Co.
Lafayette, Indiana
Vlncennes Paper Mills Inc.
Vincennes, Indiana
Container Corp. of America
Vabash, Indiana
Packaging Corp. of America
Tama, Iowa
Packaging Corp. of America
Hutchinson, Kansas
Contd.
Yorktowne Paper Mills of Maine,
Gardiner, Maine
Keys Bibre Co.
Watervllle, Maine
Chesapeake Paper Board Co.
Baltimore, Maryland
Simkins Industries, Inc.
Cantonsvllle, Maryland
Federal Paper Board Co., Inc.
Whitehall, Maryland
Bird and Son, Inc.
East Wapole, Massachusetts
Haverhill Paperboard Corp.
Haverhill, Massachusetts
Sonoco Products Co.
Holyoke, Massachusetts
Perkit Folding Box Corp.
Hyde Park, Massachusetts
Lawrence Paperboard Corp.
Lawrence, Massachusetts
Newark Boxboard Co.
Natick, Massachusetts
Michigan Carton Co.
Battle Creek, Michigan
Simplex Industries
Constantine, Michigan
Packaging Corp. of America
Grand Rapids, Michigan
Brown Co.
Kalamazoo, Michigan
Lawrence Paper Co.
Lawrence, Kansas
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APPENDIX 1 , Contd.
Waste Paperboard Mills in the U.S., Contd.
National Gypsum Co.
Kalamazoo, Michigan
Time Container Corp.
Monroe, Michigan
Union Camp Corp.
Monroe, Michigan
Mead Corp.
Otsego, Michigan
Rockford Paper Mills, Inc.
Rockford, Michigan
Weyerhaeuser Co.
White Pigeon, Michigan
U.S. Gypsum Co.
N. Kansas City, Missouri
Groveton Paper Board, Inc.
Groveton, New Hampshire
Hoague Sprague Div., USM Corp.
West Hopkinton, New Hampshire
MacAndrevs & Forbes Co.
Camden, New Jersey
U.S. Gypsum Co.
Clarks, New Jersey
Whippany Paper Board Co.
Clifton, New Jersey
Georgia-Pacific Corp.
Delalr, New Jersey
National Gypsum Co.
Garwood, New Jersey
Boyle Co.
Hershey City, New Jersey
Davey Co.
Jersey City, New Jersey
National Gypsum Co.
Millington, New Jersey
Newark Boxboard Co.
Newark, New Jersey
Morris Paper Board Co.
Patterson, New Jersey
Lincoln Paper Mills, Inc.
Ridgefield Park, New Jersey
Whippany Paper Board Co.
Whippany, New Jersey
Sonoco Products Co.
Amsterdam, New York
Climax Mfg. Co.
Carthage, New York
Brown Co.
Castelton-on-Hudson, New York
Columbia Corp.
Chatham, New York
Cornwall Paper Mills Co.
Cornwall, New York
Beaverboard Co., Inc.
Lockport, New York
Mantlsco Paper Co., Inc.
Marcellus, New York
Columbia Corp.
North Hooslch, New York
Boundary Paper Mills, Inc.
North Tonawanda, New York
U.S. Gypsum Co.
Oakfield, New York
Federal Paper Board Co.,
Piermont, New York
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Waste Paperboard Mills in the U.S.,
Warrensburg Board & Paper Corp.
VJarrensburg, New York
Carolina Paper Board Corp.
Charlotte, North Carolina
Federal Paper Board Co.
Roanoke Rapids, North Carolina
Crown-Zellerbach Corp.
Baltimore, Ohio
Tecumseh Corrugated Box Co.
Brecksville, Ohio
Container Corp. of America
Cincinnati, Ohio
Mead Corp.
Cincinnati, Ohio
St. Regis Paper Co.
Coschocton, Ohio
Stone Container Corp.
Franklin, Ohio
U.S. Gypsum Co.
Gypsum, Ohio
Loroco Industries, Inc.
Lancaster, Ohio
Diamond International Corp.
Lockland, Ohio
Massllon, Paper Co.
Massllon, Ohio
Diamond International Corp.
Middletown, Ohio
Middletown Paperboard Co.
Middletown, Ohio
Sonoco Products Co.
Munroe Falls, Ohio
Contd.
Packaging Corp. of America
Rittman, Ohio
Federal Paperboard Co., Inc.
Steubenville, Ohio
Packaging Corp. of America
Delaware Water Gap, Pennsylvania
Brandywine Paper Corp.
Downingtown, Pennsylvania
Sonoco Products Co.
Downingtown, Pennsylvania
American Paper Products Co.
Lancaster, Pennsylvania
National Gypsum Co.
Milton, Pennsylvania
Container Corp. of America
Philadelphia, Pennsylvania
Crown Paper Board Co.
Philadelphia, Pennsylvania
Newman & Co., Inc.
Philadelphia, Pennsylvania
Federal Paper Board Co.
Reading, Pennsylvania
Interstate Interior Corp.
Reading, Pennsylvania
Tim-Bar Paper Co.
Reading, Pennsylvania
Whlppany Paper Board Co.
Reigelsvllle, Pennsylvania
Westvaco Corp.
Williamsburg, Pennsylvania
St. Regis Paper Co.
York, Pennsylvania
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APPENDIX 1, Contd.
Waste Paperboard Mills in the U.S., Contd.
Yorktowne Paper Mills, Inc.
York, Pennsylvania
Carotell Paper Board Corp.
Taylors, South Carolina
Container Corp. of America
Chattanooga, Tennessee
Tennessee Paper Mills, Inc.
Chattanooga, Tennessee
Sonoco Products Co.
Newport, Tennessee
TXI Paper Products, Inc.
Dallas, Texas
U.S. Gypsum Co.
Galena Park, Texas
Federal Paper Board Co., Inc.
Richmond, Virginia
Fiberboard Corp.
Sumner, Washington
Container Corp. of America
Tacoma, Washington
Banner Fibreboard Co.
Wellsburg, Washington
Beloit Box Board Co.
Belolt, Wisconsin
Menosha Corp.
Menosha, Wisconsin
St. Regis Paper Co.
Milwaukee, Wisconsin
Filter Materials, Inc.
Waupaca, Wisconsin
U.S. Paper Mills Corp.
West De Pare, Wisconsin
Federal Paper Board Co.
Richmond, Virginia
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