EPA
Development Document for Effluent Limitations Guidelines
and New Source Performance Standards for the
UNBLEACHED KRAFT
& SEMICHEMICAL PULP
Segment of the Pulp,Paper,and
Paper board Mills
Point Source Category
May 1974
1 U.S. ENVIRONMENTAL PROTECTION AGENCY
% Washington, D.C. 20460
\'
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DEVELOPMENT DOCUMENT
for
EFFLUENT LIMITATIONS GUIDELINES
and
NEW SOURCE PERFORMANCE STANDARDS
for the
UNBLEACHED KRAFT AND SEMICHEMICAL PULP
SEGMENT OF THE
PULP, PAPER AND PAPERBOARD MILLS
POINT SOURCE CATEGORY
Russell E. Train
Administrator
James L. Agee
Assistant Administrator for Water
and Hazardous Materials
y1
Allen Cywin
Director, Effluent Guidelines Division
Craig Vogt
Project Officer
May 1974
Effluent Guidelines Division
Office of Water and Hazardous Materials
U.S. Environmental Protection Agency
Washington, D.c. 20460
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Abstract
This document presents the findings of a study of the unbleached kraft,
semi-chemical and paperboard segment of the pulp, paper, and paperboard
industry for the purpose of developing effluent limitations for existing
sources and standards of performance for new sources to implement
Sections 30U (b) and 306 of the Federal Water Pollution Control Act
Amendments of 1972 (The "Act"). The first phase of the study is limited
to unbleached kraft mills, neutral sulfite semi-chemical (NSSC) mills,
unbleached kraft-NSCC (cross recovery) mills, and paperboard from waste
paper mills.
Effluent limitations 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 Technology
Economically Achievable," which must be achieved by existing point
sources by July 1, 1977, and July 1, 1983, respectively. "Standards of
Performance for New Sources" set forth the degree of effluent reduction
which is achievable through the application of the best available
demonstrated control technology, processes, operating methods, or other
alternatives.
The identified technology for July 1, 1977, is good in-plant waste water
management followed by preliminary screening, primary sedimentation, and
biological treatment. The 1977 limitations can be met by mills
utilizing only secondary treatment, but a combination of in-plant
controls and biological treatment may be more cost effective.
The identified technology for July 1, 1983, is in-plant waste water
controls and secondary treatment. The identified in-plant controls may
require some major changes in existing processes and design
modifications to existing equipment. In addition, filtration with
possibly chemical addition and coagulation is identified for TSS
reduction. Physical-chemical treatment for color removal is identified
for four of the five subcategories.
The identified technology for new source performance standards is in-
plant waste water controls and secondary treatment. Physical-chemical
treatment for color removal is identified for two subcategories. The
identified in-plant controls and external treatment systems are
available for implementation as they have all been demonstrated at mills
within the subcategories under study.
Supportive data and rationale for development of the effluent
limitations and standards of performance are contained in this report.
m
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CONTENTS
Section Page
I Conclusions 1
II Recommendations 3
Best Practicable Control Technology
Currently Available 3
Best Available Technology Economically
Achievable 4
New Source Performance Standards 6
III Introduction 9
Purpose and Authority 9
Summary of Methods Used for Development of the
Effluent Limitations Guidelines and
Standards of Performance 10
General Description of Industry Segments 15
Products 19
Daily Production Capacity and Distribution 19
Annual Production 20
Pulp and Papermaking Process 20
Unbleached Kraft 20
NSSC Process 25
Kraft-NSSC (Cross Recovery) 30
Paperboard from Waste Paper 32
IV Subcategorization of the Industry 35
Factors of Consideration 35
Rationale for Selection of Subcategories 36
Raw Material 36
Production Processes 37
Products Produced 38
Age and Size of Mills 39
Geographical Location 39
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V Water Use and Waste Characterization
Wood Preparation 45
Pulping Processes 52
Unbleached Kraft 52
Sodium Base NSSC 58
Ammonia Base NSSC 64
Kraft -NSSC (Cross Recovery) 71
Paperboard from Waste Paper 71
Paper Machines 80
VI Selection of Pollutant Parameters 83
Waste Water Parameters of Significance 83
Rationale for Selection of Identified Parameters 83
Biochemical Oxygen Demand (5 day-20 c) 83
Suspended Solids 84
pH 85
Color 86
Ammonia Nitrogen 87
Rationale for Parameters Not Selected 88
Settleable Solids 88
Turbidity 88
Coliform Organisms 89
Resin Acids 90
Polychlorinated Biphenyls 90
VII Control and Treatment Technologies 91
Unbleached Kraft 94
Internal Technologies 94
External Technologies 104
Removal of Suspended Solids 104
BOD5 Reduction 107
Two Stage Biological Treatment 112
Temperature Effects 113
Sludge Dewatering and Disposal 114
By-product Usage 117
Color Removal 119
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CONTENTS
Section
Additional Reductions of Suspended Solids
and Refractory Organics '*'
NSSC-Sodium Base lbb
Internal Technologies 155
External Technologies 1"
NSSC-Ammonia Base 164
Internal Technologies 164
External Technologies 164
Kraft-NSSC (Cross Recovery) 173
Paperboard from Waste Paper 1 76
Internal Technologies 176
External Technologies 177
Irrigation and Land Disposal of Effluents 181
Unbleached Kraft 181
NSSC 182
Paperboard from Waste Paper 182
VIII Costs, Energy, Non-Water Quality Aspects
and Implementation Requirements 183
Rationale for Development of Costs 183
Development of Effluent Treatment Costs 183
Energy Requirements 198
Non-Water Quality Aspects of Control and
Treatment Technologies 201
Air Pollution Potential 201
Noise Potential 201
Solid Wastes and Their Disposal 203
By-product Recovery 205
Implementation Requirements 207
Availability of Equipment 207
Availability of Construction Manpower 210
Construction Cost Index 210
Land Requirements 211
Time Required to Construct Treatment Facilities 211
IX Best Practicable Control Technology Currently Available 215
Introduction 215
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section
CONTENTS
Effluent Reduction Attainable Through the
Application of Best Practicable Control
Technology Currently Available 216
Identification of Best Practicable Control
Technology Currently Available 217
Internal Controls 217
External Treatment 220
Rationale for Selection of Best Practicable Control
Technology Currently Available 221
Age and Size of Equipment and Facilities 221
Process Changes 221
Non-Water Quality Environmental Impact 221
Cost of Application in Relation to Effluent
Reduction Benefits 222
Processes Employed 223
Rationale for Selection of Effluent Limitations 223
Unbleached Kraft 223
NSSC-Ammonia Base 226
NSSC-Sodium Base 227
Kraft'NSSC (Cross Recovery) 227
Paperboard from Waste Paper 232
All Subcategories-pH Range 232
Best Available Technology Economically Achievable 237
Introduction 237
Effluent Reduction Attainable Through Application
of the Best Available Technology Economically
Achievable 238
Identification of the Best Available Technology
Economically Achievable 240
Internal Controls 240
External Treatment 241
Rational for Selection of the Best Available
Technology Economically Achievable 242
Age and Size of Equipment and Facilities 242
Process Changes 242
Engineering Aspects of Control Technique
Applications 242
Non-water Quality Environmental Impact 242
Cost of Application in Relation to Effluent
viii
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CONTENTS
section
Reduction Benefits 243
Processes Employed 243
Rationale for Development of BATEA Effluent
Limitations 244
XI New Source Performance Standards 247
Introduction 247
Effluent Reductions Attainable Through the
Application of New Source Performance
Standards 247
Identification of Technology to Achieve the New
Source Performance Standards 249
Rationale for Selection of Technology for New
Source Performance Standards 249
Type of Process Employed and Process Changes 249
Operation Methods 249
Batch as Opposed to Continuous Operation 250
Use of Alternative Raw Materials and Mixes
of Raw Materials 250
Use of Dry Rather Than Wet Processes (Including
Substitution of Recoverable Solvents for Water) 250
Recovery of Pollutants as By-products 250
Cost of Application in Relation to Effluent
Reduction Benefits 251
Rationale for Development of New Source Performance
Standards 251
XII Acknowledgements 253
XIII References 255
XIV Glossary 265
Appendices 271
ix
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TABLES
TABLES Pa3e
1. BPCTCA Effluent Limitations. 3
2. BATEA Effluent Limitations. 4
3. NSPS. 6
U. Short Term Survey Data comparison. ™
5. Number of Mills Per Source of Information. 16
6. Pulp and Paper Industry - Pulp Production. 1°
7. Size vs Raw Waste Characteristics - Unbleached Kraft. 40
8. Size vs Raw Waste Characteristics - Paperboard from
Waste Paper. 41
9. Analysis of Wet Drum Barking Effluents. 46
10. Analysis of Hydraulic Barking Effluents. 48
11. Sewer Losses from Wet Barking Operations. 50
12. Raw Waste Characteristics - Unbleached Kraft
(Literature Data), 55
13. Raw Waste Characteristics - Unbleached Kraft
(Mill Records) . 56
14. Raw Waste Characteristics - NSSC - Sodium Base
(Mill Records). 62
15. Raw Waste Characteristics - NSSC -* Sodium Base
(Literature) . 63
16. Evaporation Plant Waste Load Reduction and Secondary
Condensate Discharge Loads - NSSC - Ammonia Base. 68
17. Raw Waste Characterization - NSSC - Ammonia Base. 69
18. Raw Waste Characteristics - NSSC - Ammonia Base. 70
19. Raw Waste Characteristics - Unbleached Kraft -
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Page
NSSC (Cross Recovery). 73
20. Raw Waste Characteristics - Paperboard from Waste 74
Paper (Literature Data).
21. Raw Waste Characteristics - Paperboard from Waste
Paper (Mill Records). yg
22. Raw Waste Characteristics - Summary. go
23. Summary of Internal Technologies. 02
2H. Summary of External Technologies. 93-94
25. Reuse of Effluent from Different Unit Operations. gg
26. Mill Data - Unbleached Kraft. jQ5
27. Mill Effluent Data - Unbleached Kraft. I0g
28. Vacuum Filtration Rates of Sludges. -iic
29. Sources of color. 12Q
30. Unit Process Flow and Color Distribution in Individual
Kraft Pulping Effluent. 12Q
31. Color Reduction by Minimum Lime Treatment. 123
32. Color Removal in Biological Oxidation - Carbon
Adsorption Sequence. 129
33. Color Removal by Primary Clarification - Carbon
Adsorption Sequence. 129
3U. Color Removal by Lime Treatment - Carbon Adsorption
Sequence at Soluble Calcium Range of 69-83 mg/1. 132
35. Removal of Color and TOC by FACET Carbon Adsorption
Following Lime Treatment for 12 Day Period. 133
36. Waste Water Renovation - Summary of Results. 134
37. Renovated Water Analysis - Unbleached Kraft Linerboard
Total Mill Effluent (Pilot Plant Run No. 1) . 135
38. Renovated Water Analysis - Unbleached Kraft Linerboard
Total Mill Effluent (Pilot Plant Run No. 2) . 136
39. Results of Granular Activated Carbon Column Pilot
Plant Treating Unbleached Kraft Mill Waste. 14g
xii
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Page
40. Results of Activated Carbon Pilot Plants Treating
Unbleached Kraft Mill Effluents. 149
41. Mill Data - NSSC - Sodium Base. 158
42. Mill Effluent Data - NSSC - Sodium Base. 159
43. Summary of Results of Treatment by Reverse Osmosis. 162
44. Mill Data - NSSC - Ammonia Base. 165
45. Mill Effluent Data - NSSC - Ammonia Base. 166
46. Mill Data - Unbleached Kraft - NSSC (Cross Recovery). 174
47. Mill Effluent Data - Unbleached Kraft - NSSC
(Cross Recovery) . ''5
48. Mill Data - Paperboard from Waste Paper. 178
49. Mill Effluent Data - Paperboard from Waste Paper. 179
50. Internal Control Technologies Used in the Development
of costs. 186-190
51. External Control Technologies Used in the Development
of costs. 191-192
52. Effluent Treatment Cost and Quality for Unbleached
Kraft Mill. 193
53. Effluent Treatment Cost and Quality for NSSC - Sodium
Base Mill. 194
54. Effluent Treatment Cost and Quality for NSSC - Ammonia
Base Mill. 195
55. Effluent Treatment Cost and Quality for Kraft - NSSC
(Cross Recovery) Mill. 196
56. Effluent Treatment Cost and Quality for Paperboard from
Waste Paper Mill. 197
57. Power Costs. 199
58. Energy Requirements. 200
59. BPCTCA Effluent Limitations. 216
60. Cost of Application of BPCTCA. 222
xlii
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Page
61. Best Performers - Mill Data - Unbleached Kraft. 224
62. Best Performers - Mill Effluent Data - Unbleached
Kraft. 225
63. Best Performers - Mill Data - NSSC - Sodium Base. 228
6tt. Best Performers - Mill Effluent Data - NSSC -
Sodium Base. 229
65. Best Performers - Mill Data - Unbleached Kraft - NSSC -
(Cross Recovery). 230
66. Best Performers T Mill Effluent Data - Unbleached
Kraft - NSSC (Cross Recovery). 231
•6^. -Best Performers - Mill Data - Paperboard from Waste
Paper. 234
68. Best Performers - Mill Effluent Data - Paperboard
from Waste Paper. . 235
69. BATEA Effluent Limitations. 238
70. Cost of Application of BATEA. 243
71. Applicable External Technologies in the Development
of BATEA Limitations. 245
72. NSPS. 248
73. Cost of Application of NSPS. 251
7U. Applicable External Technologies in the Development
of standards for New Sources. 252
XIV
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Figures
Page
1. Distribution of Unbleached Kraft, NSSC, and Unbleached
Kraft - NSSC Mills in the U.S. (1973) 21
2. Distribution of Paperboard from Waste Paper Mills in
the U.S. (1973) 22
3. Kraft Pulping Process Diagram 24
U. Kraft Pulping Recovery System Process Flow Diagram 26
5. Fourdrinier Paper Machine Process Diagram 27
6. Neutral Sulfite Semi-Chemical Pulp Process Diagram 29
7. Process Flow Diagram of Spent Liquor Recovery Systems
at Combined Unbleached Kraft - NSSC Mills
8. Paperboard from Waste Paper Mill Process Diagram
34
9. Raw Waste Characteristics vs Size of Mill -
Unbleached Kraft 42
10. Raw Waste characteristics vs Size of Mill -
Paperboard from Waste Paper 43
11. Long Term BOD of Barker Effluent 49
12. Settling Rate of Barker Screening Effluent 51
13. Relationship between Total Soluble Solids, BOD,
Conductance 6 Light Absorption in Kraft Pulping
Decker Filtrate Effluent 53
14. Process Flow and Materials Diagram for a 907 Metric
Ton-A-Day Kraft Linerboard Mill 54
15. BOD Load of NSSC Pulping 59
16. Suspended Solids Losses from NSSC Pulping 60
17. Process Flow and Materials Diagram for a 227 Metric Ton
Per Day NSSC Mill 65
18. Process Flow and Materials Diagram of a Paperboard from
Waste Paper Mill 72
19. Process Flow Diagram of Mill Effluent Treatment 109
xv
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Page
20. Sludge Dewatering and Disposal 118
21. Massive Lime Process for Color Removal 122
22. Minimum Lime Process for Color Removal 124
23. Minimum Lime Process for Color Removal with
Lime Recovery 126
2U. Activated Carbon Pilot Plant 128
25. Color Removal in Lime Treatment as a Function of Soluble
Ca in Water 131
26. Simplified Ultrafiltration Flow Schematic 139
27. Simplified Amine Treatment Process Flow Diagram 140
28. Economy in scale - Carbon Absorption Systems 151
29. Effects of Tower Depth on Ammonia Removal at Various
Depths 170
30. Effects of Hydraulic Loading on Ammonia Removal at
Various Depths 171
31. Effects on Packing Spacing on Ammonia Removal 172
32. Total Water Pollution Control Expenditures 208
33. Wastewater Treatment Equipment Sales 209
3U. Engineering News Record Construction Cost Index 212
35. Land Required for Waste Water Treatment 213
36. Time Required to Construct Waste Water Facilities
Conventional and Turnkey Contracts 214
xv 1
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SECTION I
CONCLUSIONS
For the purpose of establishing effluent limitations and standards of
performance, the unbleached kraft, neutral sulfite, semi-chemical and
paperboard segments of the pulp, paper and paperboard manufacturing
industry have been subcategorized as follows:
Unbleached Kraft
Neutral Sulfite Semi-Chemical (NSSC) - Sodium Base
NSSC - Ammonia Base
Unbleached Kraft - NSSC (Cross-Recovery)
Paperboard from Waste Paper
Within each identified subcategory, factors such as age, size of plant,
process employed, climate, and waste treatability confirm and
substantiate this subcategorization for the purpose of establishing
effluent limitations and new source performance standards to be achieved
through the application of identified treatment and control
technologies.
An extensive search for information and data for mills within the above
subcategories resulted in a very broad data base. Information and data
were gathered from all possible sources including mill records, waste
water sampling surveys, technical and trade associations, literature,
NPDES permit applications, and interviews with industry authorities.
The effluent limitations and performance standards were based upon
extensive analysis of the accumulated information and data as described
above. Identification of the technology levels of BPCTCA, BATEA, and
NSPS were made and effluent qualities which could be achieved by each of
the technologies were determined.
Evaluation of all available information and data resulted in the
selection of the following significant waste water parameters for which
limitations were developed:
Biochemical Oxygen Demand (five day-20°C) (BOD5)
Total Suspended solids (TSS)
PH
Color (not including Paperboard from Waste Paper Mills)
Ammonia Nitrogen (NSSC-Ammonia Base only)
Limitations have been set forth for BOD5, TSS, and pH for July 1, 1977.
The identified technologies of BPCTCA include good in-plant waste water
management followed by external controls of preliminary screening,
primary sedimentation, and biological treatment. The 1977 limitations
can be met by mills using only secondary treatment, but a combination of
in-plant controls and biological treatment may be more cost effective.
It is estimated that increases in production costs to achieve the 1977
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effluent limitations will range from less than $0.91 per metric ton
($1.00 per short ton) up to $12.70 per metric ton ($14.00 per short ton)
depending upon specific mill conditions relating to available
technologies at the particular mill.
Limitations have been set forth for BOD5, TSS, and pH for July 1, 1983.
Also, color limitations have been set forth for four subcategories. In
addition, ammonia nitrogen limitations are recommended but not specified
for one subcategory. The identified technologies of BATEA include in-
plant waste water controls and secondary treatment. The identified in-
plant controls may require some major changes in existing processes and
design modifications to existing equipment. In addition, coagulation
and filtration are identified for TSS reduction, and physical-chemical
treatment is identified for color removal for four of the five
subcategories. The estimated increases in production costs of upgrading
existing mills from BPCTCA to BATEA range from less than $0.91 per
metric ton ($1.00 per short ton) up to $6.35 per metric ton ($7.00 per
short ton) depending upon specific mill conditions.
For new sources, standards have been set forth on BOD^, TSS, and pH for
all subcategories and color for two subcategories. The identified
technologies for new sources includes in-plant waste water controls and
external treatment. The external treatment consists of secondary
treatment and for two subcategories, physical-chemical treatment for
color reduction. The in-plant controls reflect internal improvements
which can be achieved through effective design and layout of mill
operations. The identified in-plant controls and external treatment
systems are available for implementation as they have all been
demonstrated at mills within the subcategories under study.
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SECTION II
RECOMMENDATIONS
Based upon the technology described in this report, the following
effluent limitations and standards of performance are for the
subcategories studied.
Best Practicable Control Technology Currently Available
The effluent limitations for best practicable control technology
currently available (BPCTCA) are shown in Table 1.
Table 1
BPCTCA Effluent Limitations
Values in kg/kkg (Ibs/ton)
Subcategory
Unbleached Kraft
NSSC-Ammonia
NSSC-Sodium
Unbleached
Kraft-NSSC
Paperboard from
Waste Paper
BOD5
30 Day Dally Max
2.8 (5.6) 5.6 (11.2)
4.0 (8.0) 8.0 (16.0)
4.35(8.7) 8.7 (17.4)
TSS
30 Day Daily Max
6.0 (12.0) 12.0 (24.0)
5.0 (10.0) 10.0 (20.0)
5.5 (11.0) 11.0 (22.0)
4.0 (8.0) 8.0 (16.0) 6.25(12,5) 12.5 (25.0)
1.5 (3.0) 3.0 (6.0) 2.5 (5.0) 5.0 (10.0)
pH for all subcategories shall be within the range of 6.0 to 9.0
The maximum average of daily values for any 30 consecutive day period
should not exceed the 30 day effluent limitations shown above. The
maximum for any one day should not exceed the daily maximum effluent
limitations as shown above. The limitations shown above are in
kilograms of pollutant per metric ton of production (pounds of pollutant
per short ton of production). Production is defined as the annual
average production off the machine (air dry tons). Effluents should
always be within the pH range of 6.0 to 9.0.
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The TSS parameter is measured by the technique utilizing glass fiber
filter disks as specified in Standard Methods for the Examination of
water and Wastewater (13th Edition) (1)7
Best Available Technology Economically Achievable
The effluent limitations for best available technology economically
achievable (BATEA) are shown in Table 2.
Table 2
BATEA Effluent Limitations
Values in kg/kkg (Ibs/ton)
Subcateqory
Unbleached
Kraft
NSSC - Ammonia
NSSC - Sodium
Unbleached
Kraft - NSSC
Paperboard from
Waste Paper
BOD5
30 Day Daily Max
TSS
30 Pay
Daily Max
1.35
3.2
2.25
1.6
0.65
(2.
(6.
(*•
(3.
(1.
7)
<0
5)
2)
3)
2.7
6.4
4.5
3.2
1.3
(5
(12
(9
(6
(2
.<»)
.8)
.0)
• <*)
• 6)
1.
2.
2.
2.
0.
85
6
5
1
8
(3
(5
(5
(<*
(1
.7)
.2)
.0)
.2)
.6)
3.7
5.2
5.0
4.2
1.6
(7.4)
(10.4)
(10.0)
(8.4)
(3.2)
Subcateqory
Unbleached
Kraft
NSSC - Ammonia
NSSC - Sodium
Unbleached
Kraft - NSSC
Paperboard from
Waste Paper
Color
30 Day Daily Max
10 (20) 15 (30)
75 % removal
75 % removal
12.5 (25) 18.75 (37.5)
pH for all subcategories shall be within the range of 6.0 to 9.0
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The maximum average of daily values for any 30 consecutive day period
should not exceed the 30 day effluent limitations shown above. The
maximum for any one day should not exceed the daily maximum effluent
limitations shown above. The limitations are in kilograms of pollutant
per metric ton of production (pounds of pollutant per short ton of
production). Production is defined as the annual average production off
the machine (air-dry-tons). Effluents should always be within the pH
range of 6.0 to 9.0.
Effluent limitations are needed for ammonia nitrogen for NSSC-ammonia
base mills only. However, no specific limitations have been established
because of the extreme lack of meaningful data, and because of the lack
of applied technology for ammonia nitrogen removal at the concentrations
cited. Currently, only two such mills exist and preliminary indications
are that discharges in the range of 7.5-10,0 kg/kkg (15-20 Ibs/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. Extensive studies on effective methods for the removal of
nitrogen in these concentrations must be carried out before specific
effluent limitations can be established.
The TSS parameter is measured by the technique utilizing glass fiber
filter disks as specified in Standard Methods for the Examination of
Water and Wastewater (13th Edition) (1).
The color parameter is measured by the NCASI testing method as described
in NCASI Technical Bulletin J253 (See Appendix V) (2). The above color
limitations of 75% removal for both sodium and ammonia base NSSC will be
changed to kilograms of color per metric ton of production (pounds of
color per short ton of production) at a later date when the color
removal technologies have been proven through further development.
Color units are to be assumed equal to mg/1 in determining kilograms
(pounds) of color per metric ton (short ton) of production.
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New Source Performance Standards
The new source performance standards (NSPS) are shown in Table 3.
Subcateqorv
Unbleached
Kraft
NSSC - Ammonia
NSSC - Sodium
Unbleached
Kraft - NSSC
Paperboard from
Waste Paper
Table 3
New Source Performance Standards
Values in kg/kkg (Ibs/ton)
BODS
30 Day
Daily Max
1.55 (3.1) 3.1 (6.2)
3.75 (7.5) 7.5 (15.0)
2.6 (5.2) 5.2 (10.4)
1.9 (3.8) 3.8 (7.6)
0.75 (1.5) 1.5 (3.0)
TSS
30 Day Daily Max
3.75 (7.5) 7.5 (15.0)
3.75 (7.5) 7.5 (15.0)
3.85 (7.7) 7.7 (15.4)
4.0 (8.0) 8.0 (16.0)
2.0 (4.0) 4.0 (8.0)
Subcateaorv
Unbleached
Kraft
NSSC - Ammonia
NSSC - Sodium
Unbleached
Kraft - NSSC
Paperboard from
Waste Paper
Color
30 Bay _ Daily Max
10 (20) 15 (30)
12.5 (25) 18.75 (37.5)
pH for all subcategories shall be within the range of 6.0 to 9.0
The maximum average of daily values for any 30 consecutive day period
should not exceed the 30 day standards shown above. The maximum for any
one day should not exceed the daily maximum standards shown above. The
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standards are in kilograms of pollutant per metric ton of production
(pounds of pollutant per short ton of production) . Production is
defined as the annual average production off the machine (air-dry-tons) .
Effluents should always be within a pH range of 6.0 to 9.0.
The TSS parameter is measured by the technique utilizing glass fiber
filter disks as specified in Standard Methods for the Examination of
and Wastewater (13th Edition) (1).
The color parameter is measured by methods described in NCASI Technical
Bulletin #253 (See Appendix V) (2) . Color units are to be assumed equal
to mg/1 in determining kilograms (pounds) of color per metric ton (short
ton) of production.
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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, operating
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 paperboard from waste paper segments
of the pulp, paper, and paperboard point source categories.
Section 306 of the Act requires the Administrator, within one year after
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 categories.
The Administrator published in the Federal Register of January 16, 1973,
(38 FR 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.
The limitations in this document identify (in terms of chemical,
physical, and biological characteristics of pollutants) the level of
-------
pollutant reduction attainable through the application of the best
practicable control technology currently available and the best
available technology economically achievable. The limitations also
specify factors which must be considered in identifying the technology
levels and in determining the control measures and practices which are
to be applicable within given industrial categories or classes.
In addition to technical factors, the Act requires that a number of
other factors be considered, such as the costs or cost-benefit study and
the nonwater quality environmental impacts (including energy
requirements) resulting from the application of such technologies.
SUMMARY OF METHODS USED FOR DEVELOPMENT OF THE EFFLUENT LIMITATIONS
gyiDELINES^AND STANDARDS OF PERFORMANCE
The basic procedures used in developing the effluent limitations and
standards of performance are discussed below.
The unbleached pulping segments, exclusive of groundwood, acid sulfite,
and soda pulping segments, of the pulp and paper industry were
subcategorized based on an evaluation of available data in terms of raw
materials, process differences, waste loads, products produced, age and
size of mills, and geographical locations. The resultant subcategories
include:
1. Unbleached kraft
2. Neutral sulfite semi-chemical (NSSC) - Sodium base
3. NSSC - Ammonia base
U. Unbleached kraft - NSSC (Cross Recovery)
5. Paperboard from Waste Paper
Summary Discussion of Data Sources
The extensive data and information base which was used in the
development of the effluent limitations was generated by the methods
discussed below. The sources of data and information included the
following:
1. Mill records
2. National Council for Air and Stream Improvement, Inc. (NCASI),
specifically Special Reports 73-02 (3) and 73-03 (4)
3. American Paper Institute (API)
U. Short term verification survey results
5. EPA National Pollutant Discharge Elimination
System (NPDES) Applications
6. Literature
7. Personal interviews with recognized authorities in
the pulp and paper industry.
Mill Records
10
-------
Data were accumulated from mill records which covered in most cases at
least 12-13 months operating time. Most of the mill data were a result
of daily sampling and analysis. The mill data were carefully screened
in order to have an accurate set of data for each mill. For many of the
mills, a survey of sampling and analytical techniques was made in order
to determine the validity of the data. In addition, many mill waste
waters were also sampled for a period of 3-7 days with samples being
split between the mill laboratory and the contractor's laboratory.
NCASI
NCASI Special Reports 73_-£2 (3) an^ X2~£l («*) presented suspended solids
and BOD£ data for mills using activated sludge or aerated stabilization
basins treatment systems, respectively. The NCASI carefully screened
the data before inclusion in the publications. The data were from mill
records and represented an average of a year's operation.
API
The API provided EPA data and information as a result of coordination of
industry comments and technical meetings between the API and EPA.
Short Term Surveys
As mentioned previously, surveys were conducted of several mills for 3-7
days with a basic objective of evaluation of mill data. Twenty-four
hour composites of hourly samples were taken of the mills' waste water
during the surveys. Sampling and analytical techniques were conducted
using EPA accepted procedures. It should be noted that the resulting
data was not directly utilized in determining effluent limitations
because of the short duration of the surveys. The main objective of the
surveys was to determine the validity of the mills' data.
NPDES Applications
Data from NPDES applications represent an average operating condition
for the mills. The data frequently does not compare to data from other
sources for the same mills. Thus, the NPDES data was only used as a
comparison check to other data.
Literature
Frequently, the mill effluent data in published literature are not
correlated with the particular mill which the data represents. Also,
the reliability of the data are sometimes questionable since sampling
and analytical methods are usually not presented and the time frame
which the data represents is frequently omitted. Thus, mill effluent
data from literature sources were not directly used in determining the
II
-------
effluent limitations. However, the information and data presented in
literature do provide information on the most recent pollution control
technologies, and these sources were used as background information.
Use of Information and Data to Develop Effluent Limitations Guidelines
With the objective to identify mills which could be considered as
representing the best existing practicable control technology, a list of
every mill in each of the subcategories was compiled and is shown in
Appendix I. All available information regarding the internal processes
employed, types of products, waste treatment facilities in operation,
and quantity/quality of the waste water discharge was then tabulated for
each mill.
The above information was evaluated to determine which mills should be
investigated further by on-site surveys. The main criteria used during
the evaluation was the quantity of waste water discharge and quality of
the discharge as characterized by BOD5 and suspended solids. The former
tended to indicate the extent of in-plant control practices and the
latter the extent and performance capabilities of waste treatment
facilities. This effort resulted in a list of mills which included ten
unbleached kraft mills, six NSSC mills, seven combination kraft-NSSC
mills, and twelve paperboard from waste paper mills.
Other factors, such as production mix, age of mill, type of raw
materials used, type of digester and recovery systems, and reliability
of daily treatment records were then weighed to select mills for on-site
surveys as candidate mills exhibiting best demonstrated performance.
This procedure further reduced the list of potential candidates to 14 in
the pulping subcategories and 10 in the paperboard from waste paper
subcategory.
Prior to sending a sampling survey team to the above mills, a
reconnaissance team was sent to the mills selected from the above list.
At that time the mill personnel were briefed on the objectives of the
project, the information that was necessary for the successful
completion of the project, and the work program to be carried out by the
sampling survey team. A copy of the reconnaissance and mill survey
questionnaires is shown in Appendix IV. At that time the availability
of laboratory facilities, and the feasibility of obtaining verification
data by a field survey were determined. A tour of the plant and the
treatment facilities, and a review of the available mill records on
waste streams, both internal and external, were made. The objective of
this effort was to verify that the mill was a candidate mill exhibiting
best demonstrated performance and that the mill records could be
validated by a field survey team. The type of cost records and
information required for the project was described at this time so that
the mill would have the time to compile the information which was
required by the sampling survey team. The pre-survey visit eliminated
three candidate mills from the survey effort for the following reasons:
12
-------
flood conditions at one mill made it impossible to obtain good flow
measurements of the waste stream; and two mills were engaged in major
construction in the pulp mill which exerted an abnormal influence on the
waste water generated.
The field survey team consisted of three to seven people, depending on
the particular mill studied. The goal was to obtain analytical and flow
data on various in-plant controls and external treatment systems.
Samples were collected every hour and composited every 24 hours for
three to seven days. During the survey, composited samples were split
between the mill laboratory personnel and the survey team. Samples were
analyzed on-site by the survey team or by an independent laboratory.
All analyses were performed following methods described in Standard
Methods for the Examination of Water and Wastewater (13th Edition) (1)
or equivalent EPA accepted methods (See Appendix IV, Exhibit 2). A
typical example of the results is tabulated in Table H. One objective
of this effort was to generate an "analytical procedure factor" to be
applied to the 12 month data collected from the mill. This was to
attempt to place all data from all surveyed mills on the same analytical
base. The biggest variation and most difficulty experienced in this
procedure was in suspended solids since some mills used filter paper
with a funnel and others used asbestos or fiberglass pads with a gouch
crucible. In almost all mills, the comparative BOD5 values fell within
the limits of accuracy of the test. However, development of the
"analytical factor" did not prove to be feasible because of the wide
variations in testing procedures and much of the data did not correlate
between procedures.
The 12-month mill data, subject to any cautions indicated from the
testing procedures, were used as the basis of a broad based data bank
for each of the subcategories under study. The tons per day of
production for each mill was corrected to air dry tons (ADT) as
required. Some mill data for raw waste load were found not to include
all waste water discharges and corrections to the data were made where
necessary. The data were generally developed from 12 months of daily
records from each mill. The data presented in the following sections
are believed to be in accordance with accepted standards of the
analytical procedures verified by survey programs with an exception for
total suspended solids data which includes some mill data which were
determined by non-standard methods. The procedure used to develop the
suspended solids data presented in this report is identified as to (1)
Standard Methods (SM) which is the result of EPA accepted analytical
procedures or (2) Non-standard Methods (NSM) which is the result of
analytical techniques not following EPA accepted procedures. The NSM
data is presented but was not used in determining effluent limitations.
In addition to the above accumulated data and information, 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 in-plant and
end-of-process technologies, which are existent or capable of being
13
-------
Table 4
Short Term Survey Data Comparison
(Mill UK_2)
Date: Analysis
May 1973 BY BODS
7 Mill
EPA
8 Mill
EPA
9 Mill
EPA
10 Mill
EPA
330
265
400
280
NA
232
260
268
Raw Waste
TSS pH
NA
NA
547
270
632.1
637
384
534
10.5
NA
8.7
NA
3 8.3
NA
10.4
NA
Color
NA
NA
290
680
220
130
330
220
Primary
BOD5 TSS
430
331
430
302
240
282
250
299
NA
NA
478
66
151
332
144
476
Effluent
pH Color
9.5
NA
9.7
10.2
9.8
9.3
9.3
9.6
NA
NA
540
400
290
230
220
560
Secondary
BODS TSS
130
104
130
118
110
115
130
112
NA
NA
109
34
115
91
120
125
Effluent
pH Color
8.0
NA
8.0
8.4
9.1
8.4
8.0
8.0
NA
NA
360
270
470
340
440
560
Final Effluent
BODS TSS pH
34
30.5
33
36
21
24.7
22
26
NA
NA
83
64
77
66
163
89
7.4
NA
7.9
8.2
8.4
7.8
7.6
8.0
Color
NA
NA
400
230
400
448
400
700
Units: Color - APHA Color units
pH - pH values
TSS, BODS - milligrams per liter
-------
designed for each subcategory. It also included an identification in
terms of the amount of constituents and the chemical, 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 implementation time
were also identified. In addition, the nonwater quality environmental
impact, such as the effects of the application of such technologies upon
other pollution problems, including air, solid waste, noise, and
radiation was 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 to determine 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 and size of equipment and facilities involved, the process
employed, the 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 accumulation of data from the above sources resulted in a large data
base and is presented in Table 5. As shown in the table, the total
number of mills included in the subcategories under study is 218 of
which approximately 83 discharge to municipal systems. Of the 135 mills
discharging to receiving waters, raw waste data from mill records was
available for 64 mills. Final effluent data for mills which have
biological treatment systems were available for 30 mills.
All of the above sources were used in developing the effluent
limitations. However, it should be pointed out that the data sources
are not equal in reliability and thus, they were weighted accordingly.
The data from mill records were used as the major source in conjunction
with data from the NCASI publications and the API. Data from these
three sources were used as the basis for the effluent limitations. The
data from other sources were used mainly as backup data from which to
check the accumulated data. The short term survey data represents
essentially a little more than one data point over a year's time and
thus should be within the range of the year's operating data. The NPDES
data were used as a comparison check. Data from literature were used as
background information.
GENERAL DESCRIPTION OF INDUSTRY SEGMENTS
Paper is made from raw materials which contain adequate amounts of
cellulose fiber. The cellulose fibers must first be separated from
15
-------
TABLE 5
NUMBER OF MILLS PER SOURCE OF INFORMATION
* Subcategory of Mills Municipal
Unbleached 27 0
Kraft
NSSC- 14 1
Sodium
NSSC- 2 0
Ammonia
Kraft- 10 0
NSSC
Paperboard- 165 83
Waste Paper
Totals 218' 84
(a) Effluents from biological treatment
(b) One of the nine mills only had primary treatment
Discharging
'o Receiving
Waters
27
13
2
10
82
134
Mill Records, NCASI
NPDES
Applications
23
12
1
10
16
62
Literature
14
13
0
0
42
69
Sampling
Surveys
4
1
1
2
4
12
Raw
Waste
24
6
1
10
23
64
Final ( .
Effluent^ '
12
3
1
4
9o»
30
Best
Performers
6
1
0
y
r-
3
8
18
-------
other constituents of the fiber source and fiberized. 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, wood pulp accounts for over 98 percent of the virgin
fiber used in papermaking.
There are several methods used for pulping wood. In some, it is cooked
with chemicals under controlled conditions of temperature, pressure,
time, and pulping liquor composition (5). The various processes utilize
different 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.
The early use of kraft pulping, an alkaline chemical process, was con-
current with the ascendancy of wood as a papermaking raw material. The
process was first patented in this country more than 100 years ago and
is currently the dominant pulping method accounting for nearly 58% of
the total industry production. Table 6 shows production figures for the
segments of the pulp and paper industry. Kraft pulping is the dominant
pulping method largely for two reasons: 1) Recovery, because of the
cost of the chemicals 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 (6).
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 -—
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 (6). The process gained rapid accep-
tance particularly because of its ability to utilize the vast quantities
of inexpensive hardwoods previously considered unsuitable for producing
quality pulps (7). Also, the quality of stiffness which hardwood NSSC
pulps impart to corrugating board (6), 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 nonpolluting 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 (6).
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.H million metric tons
-------
(12.6 million short tons) were reclaimed. Paperboard from waste paper
mills consumed about 75 percent of this total (8).
Table 6
Pulp and Paper Industry
Pulp Production (excluding builders board)
Pulp 6 Paper Segments Metric Tons/year (Tons/Year) % of Production
Groundwood pulp
NSSC
Unbleached kraft
Unbleached kraft-NSSC
Bleached kraft
Bleached sulfite
Unbleached sulfite
Soda pulp
Paperboard from waste paper
Pulp from waste paper (**)
4,188,000
3,449,000
15,677,000
(*)
11,220,000
1,629,000
302,000
127,000
6,670,000
3,507,000
(4,617,000)
(3,803,000)
(17,285,000)
(*)
(12,371,000)
(1,796,000)
(333,000)
(140,000)
(7,354,000)
(3,867,000)
8.9
7.4
33.6
(*)
24.0
3.5
0.6
0.2
14.3
7.5
TOTALS 46,770,000 (51,566,000) 100.0
(*) Production figures for Unbleached kraft-NSSC are reported
in the separate values for unbleached kraft and NSSC.
(**) Used as furnish for the segments listed above
(except paperboard from waste paper).
Sources of data:
a. Post's 1973 Pulp and Paper Directory.
b. API (verbal discussions).
c. State-of-theTArt Review of Pulp and
Paper Waste Treatment-EPA
18
-------
Products »
Unbleached kraft pulps are particularly suitable for producing liner-
board which is a paperboard that is used as (1) the smooth surface
facing in "corrugated" boxes, (2) wrapping paper, and (3) 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 products which do not require the maximum tearing
resistance or folding endurance such as white paper and newsprint (6).
Paperboard made from waste paper is most familiar in a wide variety of
commercial packaging which does require a folding capability, such as
bottle carriers.
Daily Production Capacity and Distribution
The 1973 industry data show that there are approximately 27 mills in the
United States which produce nothing other than unbleached kraft pulp and
paper and/or paperboard. Their total daily capacity is about 18,140
metric tons (20,000 short tons) for pulp and nearly 22,675 metric tons
(25,000 short tons) for paper and board production. Sixteen 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 ten
unbleached kraft and NSSC mills operating with cross recovery 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)
One hundred sixty-five paperboard from waste paper mills having a daily
production capacity of about 19,047 metric tons (21,000 short tons) are
also shown.
Mills which fall within these subcategories of the pulp and paper
industry are listed in Appendix I.
The size range of these mills in terms of paper and board capacity is:
Unbleached Kraft — 181-1701 metric tons (200-1875 short tons)
NSSC-Sodium — 91-635 metric tons (100-700 short tons)
NSSC-Ammonia — 453 - 508 metric tons (500 - 560 short tons)
Unbleached Kraft-NSSC — 604-1905 metric tons (666-2100 short tons)
Paperboard from
Waste Paper — 13.6-907 metric tons (15-1000 short tons)
19
-------
The geographic distribution of the kraft and NSSC mills, and that of the
joint kraft-NSSC operations, are shown in Figure 1. Figure 2
illustrates the distribution of the paperboard from waste paper mills.
Annual Production
A total of over 15.U 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 United States in 1972 according to
preliminary American Paper Institute (API) statistics. Total unbleached
kraft paper and paperboard production was 15.6 million metric tons (17.2
million short tons); NSSC paperboard, 3.6 million metric tons (U.O
million short tons); and paperboard from waste paper, 6.9 million metric
tons (7.6 million short tons) (9). These totals include production of
mills which manufacture other products in addition to those to which
this report is addressed.
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 lignin and
separate the cellulosic 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 fiberized
upon being blown from the digester. In modern practice, the pulp is
ejected to a blowtank.
The pulp, along with the "spent cooking liquor" is then transferred to a
"brown-stock" chest, or tank, and thence to vacuum drum washers or
continuous diffusers where the spent cooking liquor is separated by
counter-current washing. In older mills, the pulp is "blown" directly
to the diffusers from the digester.
20
-------
Figure 1
DISTRIBUTION OF ITFBLEACHED KRAFT, NSSC, AND CTAFT-NSSC MILLS IK THE U.S. (1973)
Unbleached Kraft
NSSC
Kraft-NSSC
-------
Figure 2
DISTRIBUTION OF WASTE PAPERBOARD MILLS IN THE U.S. (1973)
-------
Chemical recovery necessitates a high degree of liquor separation with
as little dilution as is possible to minimize heat requirements of
evaporation (6) (10). 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 (11). Some continuous digesters contain liquor separation
and diffusion washing zones within the digester body, and in many 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
(6).
After washing, the pulp is diluted and then screened to remove knots,
uncooked chips, pitch particles, etc., and is 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.
"Weak black liquor" comes from the washing operation and contains about
10-16 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 U5 to 50 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 contact
evaporator or in a concentrator.
Cooking chemicals lost in pulping and washing are replaced with a make-
up chemical, usually sodium sulfate, or a residue with a high content of
this salt (12). 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 reduced 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 Na£S - 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-
23
-------
FIGURE 3
KRAFT PULPING PROCESS DIAGRAM
LEGEND
CHEM. a LIQUORS
PROCESS WATER
BACK WATER
EFFLUENT
STEAM a GASES
REJECTS
BY-PRODUCTS
r-J EFFLUENT
-------
drated with green liquor in slakers for reintroduction to the recovery
cycle.
The fcraft chemical recovery system is shown in Figure 4 (5).
Paper Production
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 (6). This layer is then removed from
the wire, pressed, and dried.
Two general types of machines and variations 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
paperboard on either fourdrinier or cylinder machines. The primary
operational 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 linerboard 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
drying 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 (13):
1. Impregnation of hardwood chips with cooking liquor
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.
25
-------
FIGURE
KRAFT PULPING CHEMICAL RECOVERY
white liquor
storage
WOOD
CHIPS
\
digester
WATER, b'°W pit
X
pulp washer
weak black
liquor storage
evaporator
mud
washer I
WATER
mud
thickener
LIME
STONE
dregs
washer
molten
chemical
weak liquor
storage
strong black
liquor storage
recovery
furnace
NEW SALT
CAKE
26
-------
FIGURE 5
FOURDRINIER PAPER MACHINE
PROCESS DIAGRAM
OVERFLOW
FILTERED
WHITEWATER
TANK
i
SAVE-ALL
J
PULP
CHEST
<
REFINERS
_ 1
MACHINE
CHEST
RICH WHITE
WATER TANK
COUCH PIT
WIRE PIT
MACHINE
SCREENS
FOURDRINIER
SECTION
PROCESS
WATER
PRESS
SECTION
DRIER
SECTION
LEGEND
PRODUCT and RAW MAT'L
PROCESS WATER
REFUSE WATER
EFFLUENT
27
-------
Maximum temperature is adjusted according to retention time in the
digester (13). A short cook, 1C-20 minutes at approximately 200°C. is
characteristic of screw digesters. In vertical 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
dilution (6). 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
relief 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 sodium 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 (5).
Because of these factors many mills simply evaporate and burn the spent
liquor without recovery. Evaporation is commonly accomplished in multi-
ple-effect evaporators. 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 combustion units produce sodium
sulfate which is suitable for use in kraft mill liquor systems.
Recovery of sodium base NSSC liquor alone is presently limited to a few
large mills. Three of the 1U sodium base NSSC mills under consideration
in this report — i.e., those which employ no other pulping processes —
have chemical recovery systems. Three others incinerate the liquor and
two discharge to city sewers. For these mills, the simplest recovery
practice, which is called "cross recovery", is to send the liquor to a
nearby kraft recovery system.
No successful system has been developed for chemical recovery in ammonia
base NSSC mills. In the two mills utilizing this base, the spent liquor
28
-------
FIGURE 6
NEUTRAL SULFITE SEMI-CHEMICAL
PULP PROCESS DIAGRAM
CHIP
STORAGE
TO ATMOSPHERE
STEAM
STACK
GASES
SOt- COt
*
I
.J
I""
[- *
DIGESTOR
BLOW
TANK
REFINERS
COOKING
LIQUOR
ABSORBER
SULFUR
DIOXIDE
SODIUM
CARBONATE
h
SEAL
PIT
EVAPORATOR
LIQUOR
RECOVERY OR
BURNING
FLOOR DRAINS
WASHOUTS
OVERFLOWS
UJ
WASHER
SHREDDER
PRODUCT
PRODUCT a RAW MATL.
CHEM. ft LIQUORS
PROCESS WATER
BACK WATER
STEAM a GASES
EFFLUENT
STOCK
PREP.
L_
WHITE
WATER TANK
r
EFFLUENT
PAPER MACH.
SAVE - ALL
PROCESS
WATER
I
EVAP. COND.
COOLING HZ0
29
-------
is incinerated. The combustion products are gaseous with a negligible
residue of inorganic ash (14) (15).
Paper Production
Production of paper from NSSC pulp is similar to the operations in
unbleached kraft mills as discussed previously.
Kraft-NSSC (Cross Recovery)^
A substantial number of kraft pulp mills have an accessary sodium base
neutral sulfite semi-chemical pulp mill. In most instances these are
kraft linerboard mills employing pine as a raw material from forest
areas where appreciable hardwood species grow as well. These mixed
hardwoods are harvested separately but simultaneously with the pine,
cooked by the sodium base NSSC process, and manufactured into
corrugating board. This product is compatible with linerboard since
both are required to produce container board. Such combined pulp
production also provides the simplest and most economic means for
disposing of the sodium base NSSC spent liquor since it can be intro-
duced into the kraft recovery system at one point or another to provide
make-up chemicals to the kraft liquor system. The latter requires
elements present in the NSSC liquor, sodium and sulfur, to produce white
liquor, the kraft cooking agent. Alternative methods for introducing
the spent brown NSSC liquor into the system are illustrated in Figure 7.
Kraft recovery systems can absorb spent liquor from an NSSC mill
producing about one-^third the tonnage of the kraft operation assuming
that adequate evaporator capacity is provided to accept the NSSC brown
liquor which is generally more dilute and lower in heat value than the
kraft black liquor. One mill has been able to increase this ratio
through a process employing crystalization of soda ash from the green
liquor for use in preparing NSSC cooking liquor. This limitation has
also been overcome by cooking the hardwood with green liquor, although
the pulp produced has less desirable characteristics than NSSC.
Problems which have been encountered in handling NSSC spent liquor in
kraft recovery plants are as follows:
1. Low solids content of NSSC liquor which dilutes kraft black
liquor to a degree where considerable additional evaporator
capacity and steam is required.
2. Lower heat value of NSSC liquor solids which requires evapo-
ration of combined liquors to a higher consistency making
forced feed necessary in the final evaporation effects due
to higher liquor viscosity.
3. Increased evaporator fouling and scaling problems and
the need for frequent boil-out.
4. Corrosion problems resulting from the presence of NSSC liquor
components in the system.
30
-------
FIGURE 7
METHODS EMPLOYED FOR THE INTRODUCTION OF
SPENT SODIUM BASE IJSSC LIQUOR INTO THE KRAFT RECOVERY SYSTEM
KRAFT
DIGESTERS
MSSC
LIQUOR
BLOW
TANK
PULP
WASHERS
Al T #9
c-.;_ ."L.L.- ftfe- .
EVAPORATORS
STACK
EVAPORATORS
NSSC
EVAPORATOR
STRONG
BLACK LIQUOR
J_
RECOVERY
FURNACES
DISSOLVING
TANK
WHITE
LIQUOR
CAUSTIC
SYSTEM
31
-------
5. Interference with the separation of tall oil from the kraft
black liquor.
6. The release of hydrogen sulfide on combining the two liquors
due to the low pH of the NSSC liquor.
These problems have differed in intensity from mill to mill and have
largely been overcome by various means depending upon individual circu-
stances. Separate evaporation of the brown liquor is practiced at some
mills to overcome fouling and scaling as well as tall oil separation
difficulties. Introduction of the NSSC liquor as dilution in the kraft
digesters has been practiced to reduce evaporation problems. The use of
stainless steel evaporator tubes and pH control have been successful in
arresting corrosion and hydrogen sulfide release. The practices
employed for handling NSSC in kraft systems are fully documented in
TAPPI Monograph *32 (16). Details of this practice are also reviewed
in standard textbooks on wood pulping (5) (6) (13).
While limitations of 1:3 on the basis of NSSC to kraft pulping may
appear severe, this is not usually the case because the large size of
modern linerboard mills still allows an economic size NSSC operation.
Paper Production
Production of paper in unbleached kraft-NSSC mills is similar to the
operations as discussed previously for unbleached kraft mills.
Paperboard from Waste Paper
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 (17). 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
thickener 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 laminants (17) has required some refinements to the basic
process. Some mills also have systems for dispersing the bituminous
32
-------
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 (12).
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 (18). 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 paperboard from waste paper mill is
shown in Figure 8.
-------
FIGURE 3
WASTE PAPER BOARD MILL
PROCESS DIAGRAM
r - - _.
i
C T C AM
b 1 t AM
CHtM.
LEGEND
PROD. 8 RAWMAT'L
CHEMICALS
PROCESS WATER
BACK WATER
STEAM
REJECTS
EFFLUENT-
34
-------
SECTION IV
SUBCATEGORIZATION OF THE INDUSTRY
FACTORS OF CONSIDERATION
This study is concerned with the unbleached kraft, neutral sulfite semi-
chemical, and paperboard from waste paper segments of the pulp and paper
industry. In order to identify any relevant, discrete subcategories of
these segments of the industry, the following factors were considered:
1. Raw materials
2. Production processes
3. Products produced
U, Size and age of mills
5. Waste water characteristics and treatability
6. Geographical location
After analyzing these factors, it was concluded that the pulp and paper
segments under study should be divided into the five subcategories
listed below:
Unbleached Kraft
Sodium Base Netural Sulfite Semi-Chemical
Ammonia Base Neutral Sulfite Semi-Chemical
Unbleached Kraft - NSSC (Cross Recovery)
Paperboard from Waste Paper
The subcategories are 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
also utilized for other products such as grocery sacks.
2- SODIUM BASE JSEUTRAI. SULFITE SEMI-CHEMICAL means the production
of pulp without bleaching utilizing a neutral sulfite cooking liquor
having a sodium base. Mechanical fiberizing follows the cooking stage,
and the principal product made from this pulp is the corrugating medium
or inner layer in the corrugated box "sandwich."
3. AMMONIA BASE NEUTRAL SULFITE SEMI-CHEM|CAL means the production
of pulp without bleaching, using a neutral sulfite 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.
H. UNBLEACHED KRAFT—NSSC {Cross Recovery) means the production of
unbleached kraft and sodium base NSSC pulps in the same mill wherein the
35
-------
spent NSSC liquor is recovered within the unbleached kraft recovery
process. The products made are the same as outlined above for the
unbleached kraft and NSSC subcategories, respectively.
5. PAPERBOARD FROM WASTE PAPER means the production of paperboard
products from a wide variety of waste papers such as corrugated boxes,
box board, and newspapers without doing bleaching, de-inking, or wood
pulping operations. Mills which produce paperboard products principally
or exclusively from virgin fiber are not included within this
subcategory which only covers those mills using waste paper for SOX or
more of their fibrous materials,
RATIONALE FOR SELECTION JDF^SyBCATEgpRIEg
The rationale discussed below is supported by raw waste loadings
presented in Table 22 in Section V.
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, assuming normal unit operations, by-product recovery, and in-
plant controls, a surveyed mill using southern pine had a raw waste
loading BOD5 of 1U kg/kkg (28 Ibs/ton) while a similar surveyed mill
using western pine had a raw waste loading BOD5 value of 15.5 kg/kkg (31
Ibs/ton). This difference is not significant in light of other data
from 35 similar mills using many different woods which had a typical
BOD5 range of 15 to 20 kg/kkg (30 to 40 Ibs/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
produces 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 pulping wastes which are very low in nitrogen, as
delineated in Section V.
Paperboard from waste paper 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
paperboard from waste paper differ widely from those which result from
any of the pulping processes. Within the paperboard from waste paper
subcategory, many different grades of paper are used for furnish, such
as newspapers, magazines, or old corrugated boxes. The different grades
of waste paper used as raw stock can have an effect upon the raw waste
36
-------
water characteristics and could be a basis for further
subcategorization. However, further subcategorization of mills
utilizing waste paper as their only raw material was not feasible
because of the following factors: (1) Mills have historically utilized
various grades of waste paper as they become available from market
conditions depending on product demand and waste paper cost and
availability. To further subcategorize within the paperboard from waste
paper subcategory based on the type of waste paper could discourage
waste paper recycling in that NPDES permits would be issued for a period
of years based on the specific type of waste paper being utilized at
that time. The resultant effluent limitations in the permits could
limit the mills' potential for responding to market waste paper
availabilities and product demand. (2) The waste paper utilized as
furnish are frequently mixed grades of waste paper. The quantity of a
specific grade of waste paper within the mixed grade is generally
unknown as mills generally do not keep this information in their
records. Thus, data are generally not available to accurately determine
the relationship between waste water characteristics and type of
furnish. (3) As shown in Tables U8 and 49 in Section VII, paperboard
from waste paper mill effluents can be efficiently treated by biological
treatment, and quality final effluents can be achieved by biological
treatment for a relatively wide range of raw waste characteristics.
Therefore, further subcategorization of the paperboard from waste paper
subcategory was not justified.
Thus, raw materials produce distinctly different waste water
characteristics and were a basis for subcategorization.
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 paperboard from waste paper,
no pulping 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. Since the cooking liquors and pulping processes do result
in varying waste water characteristics, process differences were used as
a basis for subcategorization.
37
-------
Products Produced
Section III discusses the wide variety of products produced by these
segments of the industry. 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
and thus have been considered but not used as a basis to subcategorize
the industry segment under study.
Specifically within the paperboard from waste paper subcategory, mills
produce both food grade and non-food grade products. The production of
food grade products generates larger quantities of waste water and raw
waste loads because health considerations preclude the reuse of certain
waste waters and reclaimed fiber. The exclusive production of food
grade products occurs in very few mills as most mills that produce food
grade products from waste paper also produce nonfood grade products.
Mill P-18 in Table 21 in Section V produces a combination of grades and
at any given time may be producing food grade products on one or two of
its machines while making non-food grade on the other. As shown in
Table 21, there is a difference between the raw waste characteristics in
terms of flow and suspended solids between mill P-18 and, for example,
mills P-16 and P-21 which make non-food grades exclusively. However,
Table U9 in Section VII reveals that there is little difference in the
final effluent in terms of kg/kkg (pounds per ton) of BOD5 and suspended
solids. This indicates that both are treatable by primary clarification
and biological treatment. In addition, the raw waste characteristics
presented in Table 21 in Section V for mill P-23, which is the only mill
in the country identified as producing food grade products exclusively,
shows relatively high TSS and flow characteristics and average BOD£
levels in comparison to the subcategory averages shown in Table 22 in
Section V. As discussed in Section V, mill P-23 possibly could reduce
its flow significantly without detriment to the food grade products.
Also, effluents from the food grade mill are treatable to levels
equivalent to non-food grade mills as shown in Table 49 in Section VII.
It should be noted that the data presented in Table 19 for mill P-23 is
the effluent from the equivalent of primary treatment. Thus, since it
is common practice to produce both food grade and non-food grade at the
same mill and because varying raw waste loads can be reduced to
acceptable levels in the final effluents by biological treatment, the
paperboard from waste paper subcategory was not further subcategorized
based on product.
It should be emphasized that mills making food grade products
principally or exclusively from virgin fiber are not included in this
subcategory. This subcategory covers only those mills using waste paper
for 80% or more of their fibrous raw material.
38
-------
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 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 kg/kkg (28 Ibs/ton) of
production in the raw waste, whereas a "new" mill built in 1971 had an
almost identical 14.5 kg/kkg (29 Ibs/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 currently operating in the United States.
Even though there is a variation in the size of mills and in raw waste
characteristics from these mills, there is no correlation between the
size of mills and their raw waste loads. Data on the size of mills and
their raw waste loads are presented in Tables 7 and 8 for the unbleached
kraft and paperboard from waste paper subcategories, respectively.
These two subcategories are presented as examples because they have the
largest number of mills within the subcategories for the segments being
studied and also have the largest amount of data available for analyses.
The data are presented graphically in Figures 9 and 10. Multiple
regression analyses of the data showed no correlation between the mills'
production and raw waste load.
Thus, the age and size of mills do not justify further subcategorization
of the industry segments under study.
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. However, the local climate can
affect biological treatment processes as climatic effects can (1) slow
biological oxidation processes through lower biological activity due to
extremely cold waste water temperatures, and (2) decrease biological
treatment efficiencies during the fall and spring when waste water
temperatures are changing and also the biological community. These
effects can be minimized in the design of the biological treatment
systems as described in Section VII. In addition other factors
frequently have a greater effect upon final effluent qualities than
climate. Also, the effects of climate can be accounted for in the
development of effluent limitations by inclusion of mills located in all
geographical locations in the data base. Thus, the industry segments
were not further subcategorized based upon geographical location or
climate.
39
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TABLE 7
Mill
UK-21
UK-11
UK-23
UK-13
UK-19
UK-20
UK-18
UK- 7
UK- 6
UK- 4
UK- 3
UK-14
UK-17
UK-2 4
UK- 2
UK-16
UK-12
UK- 8
UK- 1
UK- 5
UK- 9
UK-15
UK-10
UK-2 2
SIZE VS RAW WASTE CHARACTERISTICS
UNBLEACHED KRAFT
Production
kkg/day (tons/day)
218(240)
346(382)
372(410)
453(500)
499(550)
544(600)
635(700)
641(707)
732(807)
751(828)
794(875)
816(900)
816(900)
816(900)
824(909)
939(1035)
952(1050)
997(1099)
1020(1125)
1201(1324)
1376(1517)
1451(1600)
1464(1614)
1696(1870)
BODS
kg/kkg (Ibs/ton)
28(56.0)
19.9(39.9)
37(74.0)
12(24.0)
23.5(47.0)
24(48.0)
18(36.0)
12.5(25.0)
21.2(42.5)
15.5(31.0)
14(28.0)
13(26.0)
17.8(35.7)
58(116.0)
12.2(24.5)
15(30.0)
9(18.0)
19(38.0)
13.5(27.0)
19(38.0)
17.2(34.5)
15(30.0)
35(70.0)
40
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TABLE 8
SIZE VS RAW WASTE CHARACTERISTICS
Mill
P- 8
P-19
P-12
P-23
P- 2
P- 1
P-20
P-22
P-10
P-ll
P- 4
P- 9
P-21
P-15
P- 5
P- 3
P-14
P- 7
P- 6
P-18
P-16
P-13
P-17
PAPERBOARD FROM WASTE PAPER
Production
kkg/day (tons/day)
50(55)
56(62)
63(70)
73(80)
89(98)
91(100)
91(100)
91(100)
91(100)
91(100)
114(126)
136(150)
145(160)
145(160)
154(170)
163(180)
181(200)
185(204)
190(210)
245(270)
272(300)
272(300)
440(485)
BODS
kg/kkg (Ibs/ton)
15(30)
4( 8)
13(26)
12.5(25)
15(30)
7.5(15)
7.5(15)
9(18)
10(20)
18.5(37)
12(24)
12.5(25)
9.5(19)
16.3(32.5)
13.5(27)
12(24)
20(40)
5.5(11)
7(14)
5.5(11)
10(20)
16.5(33)
6(12)
-------
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FIGURE 10
RAW WASTE CHARACTERISTICS vs SIZE OF MILL
PAPERBOARD FROM WASTE PAPER
(Tons/day) kkg/day
to 5
496
441
385.8
330.7
275.6
220.5
209.5
198.4
187.4
176.4
165.3
154.3
143.3
132.3
121
110
99
88
77
66
55
450
400
350
300
250
200
190
180
170
160
150
140
130
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90
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40
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X
•
Scale Change X X
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v
x x
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X
x
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-
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1 2 34 56 78 9 10 11 12 13 14 15 16 17 18 19 20
kg/kkg 3OD5
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40
Ibs/ton
-------
-------
SECTION V
WATER USE AND WASTE CHARACTERIZATION
Usage of water and resultant waste water characteristics for the general
operations of (1) wood preparation, (2) pulping processes, and (3) the
paper machine are discussed in this section. Since a relatively
thorough discussion of wood preparation is presented, it should be noted
that raw waste loads resulting from wood preparation are much less than
loads resulting from pulping processes and paper production, and usually
wood preparation operations utilize waste water from another unit within
the mill. In addition, waste water characteristics are reported in this
section as averages for the amount of data available unless otherwise
noted.
WOOD_PREPARATIQN
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 (6). 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. Most 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 ( 19 ). 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 produced
is most difficult to ascertain because of the wide weight variation in
stick size and the fact that not all the wood barked at some instalr-
lations is pulped, a portion going to lumber.
It is established that this effluent is very low in color and BOD£ (20)
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 or ashes from the boiler plants, or combined with the general
flowage to the treatment works. 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 declining.
Wet barking of logs is accomplished by one of three methods: by drums,
pocket barkers, or hydraulic barkers (6) (21). Slabs are generally
handled by hydraulic units as is the larger diameter and long roundwood.
The wet drum barker consists of a slotted drum equipped with internal
45
-------
staves which knock the bark from the wood as the drum rotates in a pool
f)f water. The bark falls through the slots and is removed with the
overflow of water. These units handle from 7 to 45 cords of wood daily.
Frequently the water supplied to them is spent process water, and
recycling within the barking unit itself is often practiced. Barkers of
this type contribute BOD5 from 7.5 to 10 kilograms per metric ton (15-20
Ibs/short ton) of wood barked, and from 15 to 20 kilograms per metric
ton (30-40 Ibs/short ton) of suspended solids. Examples of the BOD5 and
suspended solids concentration of this waste water with the barkers
using fresh process water are shown in Table 9.
Wet pocket barkers are stationary machines which abrade bark from timber
by jostling and gradually rotating a confined wood stack against an end-
less chainbel-t 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 hours, 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 (5,000 to 7,000 gallons) a cord, generally carries from 0.5 to
5.0 kg/kkg (1.0 to 10 Ibs/ton) of BOD5 and from 3.0 to 27.5 kg/kkg (6.0
to 55 Ibs/ton) of TSS.
ANALYSIS OF WET DRUM BARKIN6_EFFLUENTS*
TOTAL SUSPENDED
SOLIDS SSASH BOD5
mg/1 IHS/1 mg/1
2017 — 480~
3171 21 605
2875 18 987
*The water source for wet drum barkers is frequently a waste water which
has been recycled from some other source.
46
-------
The combined discharge contains bark fines and silt, the latter varying
greatly in quantity since its presence is due mainly to soil adhering 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 ( 22 ) ( 23 ) ( 24 ) , and examples are shown in
Table 10. 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. BOD5_
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 is 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 BOD5. and
color are sometimes 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 ( 20 ) ( 22 ).
BOD5 values are also greatly affected by the species of wood barked and
the season in which the wood was cut since wood juices and water ex-
tractables are responsible for it. The BOD5. contributed by the
suspended matter present is a minor fraction of the total BOD5_. The
curves presented in Figure 11, indicate that the 15-day values are about
twice those of the five day with little further demand exerted after
this period (23). Table 11 illustrates sewer losses from wet barking
operations, while Figure 12 shows settleability characteristics of
barker screening effluent.
47
-------
TABLE 10
ANALYSIS OF HYDRAULIC BARKING EFFLUENTS
TOTAL SUSPENDED
SOLIDS % ASH
MILL gig/1 mg/1
L-ll 2362 27
L-22 889 14
L-33 1391 17
L-4U 550 11
L-55 521 13
L-66 2017 21
L-77 2000 19
L-88 600 10
IOD5
585
101
64
99
121
56
97
250
COLOR
APHA
UNITS
50
50
50
50
50
50
35
48
-------
120
FIGURE 11
LONG TERM BOD OF BARKER EFFLUENT
( AFTER FINE SCREENS)
RAW
FILTERED
100
80
•>
60
ID
Q
O
CD
40
/
20
V
10 15
DAYS INCUBATION
20
25
49
-------
TABLE 11
SEWER
Mill
L-1
L-2
L-3
L-4
L-5
L-6
L-7
L-8
1>9
LOSSES FROM WET BARKING OPERATIONS
Effluent Volume
Kiloliter/kkg
(lOOO^gal/tonl
11.3 (2.7)
10
1U
25
12
4
23
4
31
.0
.6
.0
.5
.2
.4
.2
.3
(2.
(3.
(6.
(3.
(1.
(5.
(1-
(7.
«)
5)
C)
0)
0)
6)
0)
5)
BOD5
kg/kicg
Jibs/ton)
0.
0.
6.
3.
1.
1.
9.
5.
11.
6 (1.
9 (1.
0 (12.
0 (6.
25 (2.
0 (2.
5 (19.
75(11.
05(20.
2)
8)
0)
0)
5)
0)
0)
5)
1)
TSS
kg/kkg
Jibs/ton)
3.
3.
2.
15.
11.
5.
9.
15.
17.
2
8
75
0
U
0
0
0
0
(6.
(7.
(5.
(30.
(22.
(10.
(18.
(30.
(34.
«)
6)
5)
0)
8)
0)
0)
0)
0)
50
-------
FIGURE 12
SETTLING RATE OF
BARKER SCREENING EFFLUENT
100
90
O
H-
U
D
O
U)
CE
O
tn
o
ui
o
z
ui
80
70
60
50
20
40 60 80
RETENTION TIME (MINUTES)
100
1
I
I
3240 1620 1000 810 648
CLARIFIER SURFACE LOADING-GAL./FT.2/DAY
51
-------
POLPINGJPHOCESS
A summary of raw waste characteristics for each of the subcategories is
presented in Table 22 at the end of this section.
Unbleached Kraft
The waste water resulting from unbleached kraft pumping 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-
counts for a high percentage of the total effluent. Today, the use of
hot stock washing, as discussed in Section VII, has considerably reduced
the waste load generated in the washing operation.
Relationships between solids concentration of this waste water and BOD5,
light absorbence, and conductivity are shown in Figure 13 ( 25 ). It
should be noted that the relationships shown in Figure 13 will vary
somewhat depending upon the specific case. 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 conductivity 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
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 BOD5 can be reduced by air stripping in a cooling tower (27)
or by steam stripping ( 28 ). These condensates are frequently reused
for pulp washing.
All chemical recovery operations and other minor losses constitute the
last BOD5 source from kraft pulping.
Losses per unit of production 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 kraft linerboard mill is shown in Figure 14.
As shown in Tables 12 and 13, total BOD5 raw waste load from unbleached
kraft mills, including both pulping and papermaking operations, is
52
-------
en
to
UJ
o
z
Ul
CD 3
•£ E
*8o
^00 IO
i < f
201
O
I.6'
I.2
0.8
o
jpoo- ipoo
2.500
2pOO-
0.4- IOO- 200
FIGURE- 13
to
0
O
DQ
800
600
1,500- 400
RELATIONSHIP BETWEEN TOTAL
SOLUBLE SOLIDS, BOD, CONDUCTANCE
& LIGHT ABSORPTION IN KRAFT
PULPING DECKER FILTRATE EFFLUENT
2pOO 3pOO
TOTAL SOLUBLE SOLIDS, (ma/1)
4.000
-------
WHITE LIQUOR
PURCHASED
CHIPS
WASH WATER
Na
Su
Ua
!
-* 1 — -= 1 — 1
f*
CHIP rCREEfr
i1 — ^
fur sg Tons * — *—
er 1 ,000,000 Gal . i , I_|
i TURPENTINE if
1 STORAGE
Turps. 14 Tons
Sulfur 1 .4 Tons
Water 16,000 Gal .
NaOH 5.4 Tons
Sulfur 4.6 Tons
CHIPPERS
FINES
48 tons
Cool ing Water
^
•*
BARK
BOILER *~~
DRUM BARKERS
|
BARK
673 tons
1 '
SUMP
I i 1
) \ ROUND WOOD
> 1 1168 Cords
! 150,000 Gal. _
"
208,200 Gal.
W TANKS
— TURPENTINE
DECANTER
CHEMICAL
MAKE-UP
FIBERIZER
7
J
<—
Na OH 33 Tons
Sulfur 13 Tons
TALL OIL
SOAP
f
STRONG
^
^ HOT STOCK
REFINER ,
T- 1
X . Sulfur 4.3 Tons
SEWER Water 2,000,000
BLACK LIQUOR ~~
Dis
' ' NaO
B . L . Ua f-
OXIDATION
t
^ HOT c
I SCRE
c
Gal .
TOCK
ENS
WEAK
BLACK
LIQUOR
Wash Water
250,000 Gal.
1
*•
SEWER
WASHERS
h- 1
HIGH DENSITY
STORAGE
.Org.1100 Tons Cooling Water riaOH 600 Tons
H 600 Tons n MGD Sulfur 58 Tons
fur 50 Tons Dis.Org. 1 1 50 Tons
er 220,000 Gal. Water 2,400,000 Gal.
SEWER
WHITE LIQUOR
STORAGE
Mud 500 Tons
NaOH 5.0 Tons
Sulfur 1.1 Tons
Water 76,000 Gal
Water 10,000 Gal.
Figure u
PROCESS FLOW AND MATERIALS DIAGRAM
FOR A 1,000 TON A DAY KRAFT
LINERBOARD MILL
Inerts 5 Tons
Water 24,100 Gal.
Dis.Org. 11 Tons
Fiber & Add. 9 Tons
NaOH 4.5 Tons
Sulfur .46 Tons
Water 1,000,000 Gal.
-------
Mill
1
2
3
L-UK
L-UK
L-UK
L-UK U
L-UK 5
L-UK 6
L-UK 7
L-UK 8
L-UK 9
L-UK 10
L-UK 11
L-UK 12
L-UK 13
L-UK lU
FLOW
kiloliters/kkg
(1000 gal/ton)
108
Ul
79
12
50
125
62
7(10)
2(19)
5( 3)
1(12)
1(30)
6(15)
25( 6)
50(12)
112.6(27)
50(12)
ltl.7'10)
66.7(16)
37.5( <»)
TABLE 12
RAW WASTE CHARACTERISTICS
UNBLEACHED KRAFT
BOD 5
kg/kkg
(ibs/ton)
21 (1»?)
11(22)
19(38)
17.5(35)
16.5(33)
9(18)
15(30)
13(26)
13.5(27)
50.5(101)
16.5(33)
*: Analytical Technique unknown.
Note: Mills L-UK 1 through L-UK ih are from the literature and thus no
identification is possible.
TSS*
kg/kkg
(Ibs/ton)
15(30)
20(UO)
6(12)
".5(19)
12.5(25)
11.5(23)
3>4.5(6o)
6(12)
15(30)
26.^(53)
27.5(55)
69.5(130)
-( - )
13.5(?7)
55
-------
TABLE 13
RAW WASTE CHARACTERISTICS
UNBIEACHED KRAFT
TSS
ka/kkg
Mill (1000 gal/ton) (Ibs/ton) (Ibs/ton)
FLOW
kiloliters/kkg
(1000 gal/ton)
39. 2( 9.4)
50(12.0)
39. 6( 9.5)
85.5(20.5)
60(14.4)
64.2(15.4)
112.6(27.0)
43.4(10.4)
43.4(10.4)
55.5(13.3)
43.8(10.5)
-
-
-
-
-
-
-
-
-
-
-
-
BODS
kg/kkg
(Ibs/ton)
13.5(27.0)
12.2(24.5)
14(28.0)
15.5(31.0)
19(38.0)
21.2(42.5)
12.5(25.0)
19(38.0)
17.2(34.5)
-
19.9(39.9)
9(18.0)
12(24.0)
13(26.0)
15(30.0)
15(30.0)
17.8(35.7)
18(36.0)
23.5(47.0)
24(48.0)
28(56.0)
35(70.0)
37(74.0)
UK-1 39.2( 9.4) 13.5(27.0) 10.5(21)*
UK-2 50(12.0) 12.2(24.5) 18.7(37.5)*
UK-3 39.6( 9.5) 14(28.0) 28(56)
UK-4 85.5(20.5) 15.5(31.0) 19.5(39)
UK-5 60(14.4) 19(38.0) 19.5(39)
UK-6 64.2(15.4) 21.2(42.5) 23.3(46.6)
UK-7
UK-8
UK-9 43.4(10.4) 17.2(34.5) 11.6(23.2)*
TJK-10
UK-11 43.8(10.5) 19.9(39.9) 19.1(38.1)
UK-12
UK-13
-------
typically in the 12 to 20 kilograms per metric ton (24 to 40 Ibs/ton)
range. The average raw waste BODS load for mills in Table 12 was 16.4
kg/kkg (32.8 Ibs/ton) with a range of 11 to 21 kg/kkg (22 to 42 Ibs/ton)
(not including mills L-UK-6, L-UK-7, and L-UK-12, inclusion of which
would disproportionately affect the average). The average raw waste
load for mills in Table 13 was 16.9 kg/kkg (33.8 Ibs/ton) with a range
of 12 to 28 kg/kkg (24 to 56 Ibs/ton) (not including mills UK-12, UK-22,
UK-23, and Uk-24, inclusion of which would disproportionately affect the
average). The average BOD5 raw waste load for mills UK-1 through UK-11
in Table 13, for which daily data over one year's time was available was
16.4 kg/kkg (32.8 Ibs/ton) with a range of 12.25 to 21.25 kg/kkg (24.5
to 42.5 Ibs/ton). The data presented in Table 13 is more recent data
than the data in Table 12, and it should be pointed out that the mills
in Table 12 may be included in Table 13 since identification of the
mills was not available.
The total suspended solids raw waste load for unbleached kraft mills are
generally reported to be within a range of 10 to 15 kg/kkg (20 to 30
Ibs/ton). The mills in Table 12 average 15 kg/kkg (30 Ibs/ton) with a
range of 6 to 27.5 kg/kkg (12 to 55 Ibs/ton) (not including UK-6, UK-7,
and UK-12). However, the technique utilized for TSS analysis is unknown
for mills in Table 12. The mills using SM in Table 13 average 21.9
kg/kkg (43.8 Ibs/ton) with a range of 19 to 28 kg/kkg (38 to 56
Ibs/ton), but data resulting from SM was available for only five of the
24 mills listed. Raw waste color APHA color units (CU) 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 inplant measures to reduce raw waste loads and flow is
evident in the flow data presented in Tables 12 and 13. The flows
averaged 57,550 liters/kkg (13,800 gal/ton) for the mills in Table 12
(not including L-UK-6, L-UK-7, and L-UK-12). The average flow in Table
13 was 52,550 liters/kkg (12,600 gal/ton) with a range from 39,200 to
85,480 liters/kkg (9,400 to 20,500 gal/ton) for mills UK-1 through UK-11
(except mill UK-7, inclusion would disproportionately affect the
average). In 1966, 19 unbleached kraft mills were reported (29) to have
a median water usage of 121,017 liters/kkg (29,000 gal/ton). The
details of methods utilized to accomplish this flow reduction, with
concomitant reductions in pollution levels in the raw waste, are
described in Section VII.
57
-------
Sod.'*.urn Base Neutral Sulfite Semi-chemical
In most sodium base NSSC mills, liquor is prepared by burning sulfur and
absorbing it in soda ash or ammonia, depending on base utilized. This
part of the 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.
The final effluent from sodium base NSSC mills is relatively 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.5. Without recovery or incineration of the liquor, effluents
would range from 1500 to 5000 mg/1 with a suspended solids content of
from UOO to 600 mg/1. The color and chemical oxygen demand (COD)
content would be correspondingly high ( 30 ) . Overall process losses in
BODjj and total suspended solids without recovery in relation to pulp
yield are shown in Figures 15 and 16, respectively.
As described briefly above, the raw waste load from NSSC mills is
dependent upon several factors including water use, cooking liquor
disposal or recovery, and the amount of waste paper used as furnish.
Many mills utilize old corrugated boxes or corrugated box clippings as a
portion of their furnish. The raw waste load per ton of pulp furnish is
much different for furnish from old corrugated than that from NSSC pulps
and has been reported to be approximately 10 kg BOD5_ per kkg of pulp (20
Ibs BOD.5 per ton of pulp) . The BOD5 is generally a result of the
solubilization of the starch used as a binder in corrugated board and by
the residual BOD5_ left in the corrugated box from the original kraft and
NSSC processes (31).
58
-------
FIGURE 15
cc
o
UJ
z
oc.
ui
a.
I
a.
700
600
500
400
300
200
100
BOD LOAD OF NSSC PULPING
(WITHOUT RECOVERY)
55
60
65
70
75
80
PERCENT PULP YIELD
59
-------
FIGURE 16 SUSPENDED SOLIDS LOSSES FROM NSSC PULPING
(WITHOUT RECOVERY)
z> no
Q.
s
Ul
m too
•z
p
Q
tf>
O
Z.
LU
Q.
O
U_
O
O
Z
o
a.
90
80
70
60
\
\
\
\
\
\
\
\
\
\
\
\
\
\
65
70
75
80
85
PERCENT YIELD
60
-------
The raw waste load is also affected by the methods used to dispose or
recover the waste liquor. Evaporation and incineration which is
commonly practiced by NSSC mills has been reported to contribute up to
one third of the total BOD5 raw waste load. The additional waste load
is due to the evaporator condensate plus the carryover of spent liquor
solids which occurs during evaporation.
Raw waste data for NSSC mills are shown in Tables 14 and 15. The
identity of mills in Table 15 was not available and some of these mills
may be included in Table 14. The average BOD5 raw waste load for mills
in Table 15 was 25.2 kg/kkg (50.4 Ibs/ton) with a range of 11 to 45
kg/kkg (22 to 90 Ibs/ton) (not including L-NS-13; inclusion would
disproportionately affect the average). The average TSS raw waste load
was 12.3 kg/kkg (24.6 Ibs/ton) with a range of 4 to 23 kg/kkg (8-46
Ibs/ton) (not including L-NS-13), but the TSS analytical techniques are
unknown. The average effluent flow for mills in Table 14 was 42,950
liters/kkg (10,300 gal/ton) with a range of 20,000 to 106,700 liters/kkg
(4,800 to 25,600 gal/ton) (not including NS-5, inclusion of which would
disproportionately affect the average).
The effects of furnish and waste liquor handling can be seen in Table
14. The BOD5 raw waste load for mill NS-1 was 8.5 kg/kkg (17 Ibs/ton)
while the BOD5 raw waste load for mill NS-2 was 31 kg/kkg (62 Ibs/ton).
The effluent flow was nearly the same for the mills and thus the
difference in raw waste loads apparently relates to the type of furnish
and the waste liquor handling systems. Mill NS-1 utilizes waste paper
for approximately 33X of its furnish whereas mill NS-2 uses waste paper
for only 6% of its furnish. Also, mill NS-1 spray irrigates it strong
waste liquor and mill NS-2 recovers the waste liquor through evaporation
and incineration. The data presented in Table 14 for mills NS-3, NS-4,
and NS-5 may indicate that the effects of waste liquor handling are much
more significant than the amount of waste paper utilized as furnish in
affecting the raw waste load.
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 15
(32) . For example, BOD5 loadings of 28.5 kilograms per metric ton (57
Ibs/ton) at a flow of 7094 liters/kkg (1700 gallons per ton) have been
reported (33) . As flow is progressively reduced through more extensive
in-plant measures, BOD5 can be reduced to 14.5 kilograms per metric ton
(29 Ibs/ton) at 2921 liters/kkg (700 gallons per ton). The lower value
cannot be sustained, however, because of operational problems ( 32 )
discussed in Section VII.
61
-------
TABLE 14
RAW WASTE CHARACTERISTICS
NSSC - SODIUM BASE
FLOW Waste Paper BODS' TSS
kiloliters/kkg Furnish kg/kkg kg/kkg
Mill (1000 gal/ton) % (Ibs/ton) (Ibs/ton) Remarks
NS-1 44.6(10.7) 33 8.5(17) 8.5(17) (a)
NS-2 48.8(11.7) 6 31(62) 17.5(35) (b)
NS-3 - 33 35(70)* - (b)
NS-4 - 27-37 24(48)* - (b)
NS-5 - 17-21 31(62)* - (b)
* per kkg(ton)pulp
(a) Spent liquor is spray irrigated.
(b) Evaporation and incineration of spent liquor.
Notes: Data for mills NS-1 and NS-2 are from mill records of daily
discharge data over one year's time. Data for mills NS-3, NS-4,
and NS-5 are from mill reports to the NCASI of annual waste loads.
62
-------
TABLE 15
Raw Waste Characteristics
NSSC - Sodium Base
Mill
L-NS-1
L-NS-2
L-NS-3
L-NS-4
L-NS-5
L-NS-6
L-NS-7
L-NS-8
L-NS-9
L-NS-10
L-NS-r 1 1
L-NS-1 2
L-NS-1 3
Flow
kiloliters/kkg
|1000 qal/ton)
38.
20.
30.
25.
7.
47.
41.
43.
106.
83.
29.
43.
100.
0
0
0
0
1
2
7
4
8
5
2
0
2
(9.
(4.
(7.
(6.
(1-
(11.
(10.
(10.
(25.
(20.
(7.
(10.
(24.
D
8)
2)
0)
7)
3)
0)
")
6)
C)
0)
3)
0)
BOD5
kg/kkg
(Ibs/ton)
15.
32.
21.
13.
28.
30.
45.
21.
23.
29.
21.
11.
75.
0
0
5
5
5
5
0
0
5
5
5
0
0
(30)
(64)
(43)
(27)
(57)
(71)
(90)
(42)
(47)
(69)
(43)
(22)
(150)
TSS*
kg/kkg
(Ibs/ton)
7.5 (15)
6.
4.
8.
4.
21.
14.
16.
11.
23.
50.
17.
20.
0
5
5
0
5
0
5
5
0
0
5
0
(12)
(9)
(17)
(8)
(43)
(28)
(33)
(23)
(46)
(100)
(37)
(40)
*Note: TSS measuring techniques unknown.
63
-------
Similarly, others (33) have reported a short-term average of 5.5 kg/kkg
(11 Ibs/ton) for BOD5. Again, operating difficulties are cited at this
low level, and daily variations of BOD5 range up to 25 kg/kkg (50
Ibs/ton) and higher. ~
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, reports of increased
operating problems have been reported (32). A surveyed sodium base mill
reported no operating problems due to total dissolved solids at the much
lower level of 0.2 percent. Others (33) reported difficulties in
meeting wet strength requirements of the product when total dissolved
solids of the recirculated white water reached 3.7 percent.
A process flow and materials diagram for a 227 kkg per day (250 ton per
day) sodium base NSSC corrugating board mill is shown in Figure 17.
Neutral gulfite Semi^Chemical (Ammonia Base)
The ammonia base process is similar to the sodium base process described
above, except that ammonia is utilized in the preparation of cooking
liquor in place of sodium. Waste water characteristics of the two
processes are similar, as shown in Table 22, except for the nitrogen
concentration in the liquid wastes from the ammonia base mills.
The wood preparation step does not generate a significant waste stream
since it is essentially a bark removal and chipping operation. This
generates a small stream of approximately 37.8 - 56.7 liters (10-15
gallons) per minute emanating from the chip washer.
The initial phase of pulp preparation begins with heating the chips in a
steaming vessel. The chips are then conveyed by a series of horizontal
and vertical screw feeders upward through the cooking liquor and into
the digester. The cooking liquor consists of ammonium sulfite, produced
on site, and anhydrous ammonia. The pressure and temperature in the
digestor are controlled by injection of live steam. The digested chips
are fed continuously to refiners where they pass between stationary and
rotating discs, after which the refined pulp passes into a blow tank to
be mixed and diluted to the proper consistency. The vapor and steam
from the blow tank are condensed and used elsewhere. From the blow
tank, the pulp goes into a two-stage, counter-current washer and then
into a high density storage chest. From here the pulp is pumped to the
secondary refiner and into the blend chest. The weak black liquor from
the washers, and any other wasted cooking liquor, goes to the
evaporators. The vapor off the evaporators is condensed and goes to the
sewer while the remaining black liquor is burned in a liquor disposal
unit.
The paper production stage begins after the pulp has been washed, re-
fined and blended. Pulp is removed from the blend chest and processed
64
-------
Figure 17
r n - - -
I *
COOLING
WATER
1.61 MG
r-"
PROCESS _!
WATER j
0.66 MG j_
VACUUM
PUMPS
1 .10 MG
|_
~r
1
AUXILIARY l
EQUIPMENT 1
0.32 MG |
1
BOILERS
0.14 MG
wnnn fc
CHIPS 4 -~
b. B
DIGESTERS » T
200 CORDS D'S- 200'500 *
CHEMICALS
IBR
RE
HA^TE P/WP ., »
AND BROKE
BRFAKFR ^f
BEATER
1 1
f f
JUNK 1 ""
PROCESS FLOW AND MATER
FOR A 250 TON A DAY NSSC
BOARD MILL
LEGENDS
D.S.- Dissolved
STOCK
CLEANING
1
ALS DIAGRAM
CORRUGATING
Solids
i n
t
EVAPORATOR
CONDENSER I
0.28 MG
_t _^_
CHEMICAL
ASH
A
LIQUOR
1 1 4 D.S.
I » 1
LOW LIQUOR to Fv«pnBaTnp<;
ANK SCREEN EVAPORATORS
ii | D.S. 155,500
I 0.23 MG
qNER ~~H MASHERS 1 REJECTS '
D.S. 55,000 1 M
PrriNrir — ^B
irltl1 * SCREENS
}.40 MG
f -"M-^
1 1 T
1 '' 1
1 STOCK I . 1
I CHEST | |
[ NSSC PULP _ BLENDED
1 * STOCK
to STOCK f
CKER — » CHEST |
50 Tons FIBER FI
1
1
155,000 *
V— *
J D.S. 500 #
W
RGE ^_
NK
i
1
TER
D.S. 40,000 »
t
ll PAPERBOARD |L PAPER
II 250 tons 1^ MACHINE
SEWER
1.95 MG
65
-------
through refiners, the third and last refining step. Before going to the
paper machine, the pulp passes through cleaners and screens. Excess
white water from the paper machine flows through a disc-type saveall,
where wood fiber is recovered.
Waste Water Flow
There are five sources of waste water in the manufacturing process: 1)
the evaporators, 2) the powerhouse and maintenance, 3) the pulp mill, U)
the paper machine, and 5) the waste paper plant. The latter, however,
is an insignificant source.
In the surveyed mill which produced 453 metric tons (500 short tons) per
day, all chips are washed before entering the digester for removal of
sand and dirt. Reuse-water from the hot water tank in the pulping area
is used as wash water. According to a mill study on July 17, 1972, the
chip washer contained the following effluent load:
Flow 81.3 liters/min (21.5 gpm)
SS 78.8 mg/1
Total Solids 98 mg/1
Nonvolatiles 7.6% (of total solids)
The chips washer discharges directly to a drainage ditch leading to the
holding pond. The above numbers refer to the raw solids load before
discharge into the holding pond.
No raw water is used in the pulping area. The most significant point
for water usage is at the washers where reuse water from the paper ma-
chine vacuum system is used.
Excepting floor drains, the water discharge into the pulp mill sewer
comes from the screw feeder and the paper machine saveall. To accom-
plish sufficient high dry solids content in the chips before the
digester, water is pressed out of the chips in the screwfeeder. The
screwfeeder effluent is a low flow high BOD5 concentrated stream which
contributes about 18-20 percent to the total raw BOD5 load of the mill
(Jan. 1972). A study carried out by the mill in Nov. - Dec. 1971 showed
the following effluent load from the screw feeder:
Flow 340 liters/min (90 gpm)
BOD5 4260 mg/1 (range 2180-6080)
BOD5 2090 kg/day (4600 Ibs/day)
The saveall overflow is highly variable both in flow and concentrations
depending on the amount of clarified water taken for reuse. It is also
high in BOD.5 load since it contains the dry solids loss from the
washers. This stream discharges to the pulp mill sewer.
The weak liquor recovered in the washing plant is evaporated in a qua-
druple evaporator unit to about 52 percent dryness. The thick liquor is
66
-------
burned in the recovery boiler, or disposed of on land or sold. The
combustion products are gaseous with a negligible redsidue of inorganic
ash. The gaseous products contain significant sulfur dioxide emissions.
Fresh water is used in the evaporation plant vacuum system and in the
boiler area as makeup water to the boilers. The cooling water to the
surface condenser may be recycled through a cooling tower.
The most significant effluent stream is the secondary condensate. The
condensate can be separated in three streams.
- combined condensate from middle effects
" condensate from the surface condenser
-* direct cooling water from the spray condenser and steam ejector.
The combined condensate plus the surface condenser condensate can be
diverted in one stream and discharged through a boilout tank. This
stream contains a high BOD5 and ammonia load.
The waste loads to the evaporation plant and the effluent from the plant
are summarized below for two tests during 1972 and 1973 in Table 16. As
can be seen, the condensate BODJ5 and ammonia concentrations experience
wide variations.
Effluent is discharged from the following points in the paper machine
area:
- floor drains
- gland water
- felt conditioners
- centri-cleaners
The effluent discharges to a separate sewer and is metered separately.
Table 17 shows raw waste characteristics for the combined condensates
sewer, the papermill sewer, and the total mill sewer. Table 18 shows
the raw waste characteristics of the surveyed mill based on mill records
of daily discharge data over a year's time. The average raw waste BOD5.
for the mill was 33.75 kg/kkg (67.5 Ibs/ton) and the TSS raw waste was
17 kg/kkg (34 Ibs/ton) based on KSM.
67
-------
Table 16
Evaporation Plant Waste Load Reduction and
Secondary Condensate Discharge Loads
March 1.1972
(gpm)
Flow liters/min
BOD5 mg/1
kg/day (Ibs/day)
% of Mill Load
% Reduction: Evap-
oration plant
NH3-N mg/1
kg/day (Ibs/day)
% Reduction Evap-
oration plant
January 1973
Flow liters/min (gpm)
NH3-N mg/1
kg/day (Ibs/day)
Weak Black
Liquor
983 (260)
37,900
49,900 (110,000)
81
7,000
9,260 (20,400)
69
680 (180)
9,600
9,400 (20,700)
Combined
Condensate
839 (222)
7,520
8,540 (18,800)
60-75
2,600
2,910 (6,400)
1,750 (3,860)
68
-------
Table 17
Raw Waste Characterization
NSSC - NH3-N
Combined Paper Mill Total Mill
Condensate Sewer Sewer
Flow kiloliters/day (MGD) 1,020 (0.27) 7,180 (1.9) 12,470 (3.3)
BODS* mg/1 6,120 620 630
BODS* kg/day (Ibs/day) 6,260 (13,800) 4,470 (9,840) 7,850 (17,300)
Suspended Solids mg/1 5 970 620
Suspended Solids kg/day (Ibs/day) 5 (11) 6,950 (15,300) 7,760 (17,100)
Kjeldahl Nitrogen mg/1 2,180 285 210
Kjeldahl Nitrogen kg/day (Ibs/day) 2,230 (4,910) 2,050 (4,520) 2,640 (5,810)
Ammonia Nitrogen mg/1 1,700 100 150
Ammonia Nitrogen kg/day (Ibs/day) 1,740 (3,830) 750 (1,650) 1,880 (4,130)
* Soluble
-------
Table 18
Raw Waste Characteristics
NSSC - Ammonia Base
Flow BODS TSS*
kiloliters/kkg kg/kkg kg/kkg
Mill (1000 gal/ton) (Ibs/ton) (Ibs/ton)^
N-1 3U.8 (8.33) 33.75 (67.5) 17 (34)
*NSM
70
-------
Kraft - NSSC (Cross Recovery)
Methods employed for introducing spent sodium base NSSC liquor into a
kraft recovery system are illustrated in Figure 7 in Section III. While
this is the simplest and most economic solution to the recovery problems
of this process, it can create some operational difficulties in recovery
which must be overcome, as is discussed in Section III.
Assuming solution of these problems, if ttoe ratio of the NSSC operation
does not exceed 1:3 of the kraft production, the waste characteristics
are not seriously altered. At this ratio, the BOD5 and total suspended
solids losses are increased to a small degree over those of kraft
recovery alone. NSSC pulp does not wash as well as kraft and thus, more
fines pass off in the effluent . However, in modern operations these
increases are not anticipated to exceed 10 percent of an equivalent
amount of kraft pulp alone on the basis of the 1:3 production ratio.
Treatability by biological oxidation processes is not altered by the
addition of NSSC pulping to kraft production and electrolyte
concentration of the effluent is not altered appreciably.
The raw waste characteristics for unbleached kraft-NSSC (cross recovery)
mills are shown in Table 19. The average raw waste BOD5_ load for the
mills in Table 19 was 19.4 kg/kkg (38.8 Ibs/ton) with a range from 14 to
27 kg/kkg (28 to 54 Ibs/ton) (not including mill X-10, inclusion of
which would disproportionately affect the average. The average raw
waste TSS load was 20.5 kg/kkg (41 Ibs/ton) with a range from 12.45 to
28.5 kg/kkg (24.9 to 57 Ibs/ton), but data were only available for two
mills which were using SM. The average flow for mills X-1 through X-4
was 58,380 liters/kkg (14,000 gal/ton) with a range from 43,370 to
74,230 liters/kkg (10,400 to 17,800 gal/ton).
Paperboard from Waste Paper
The raw waste load of paperboard from waste paper 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
BOD5 value per ton of product. Mills whose wastes have the higher BOD5
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 BODf> loads. A process flow and materials
diagram of a typical paperboard from waste paper mill is shown in Figure
18.
Effluent volume, BOD5, and total suspended solids data for 42 mills have
been collected and are presented in Table 20. The data were compiled
71
-------
BROKE 1~ ~| 0 574 MG
5 Tons I 2.014 HG 0.144 MG
HASTE J
PAPER 1
// Ions
REJECTS
2 Tons
1.18 HG
p LPER UUI-IP CUSI p 1.™ -j THICKENER
j 1 ton j
1 1 .44 MG W.W. TANK
CHEST
0.57 MG
1 80 Tons
- K87 HG RLUNLK
11 D10Mi Vflr FTITFQ Recovered Fiber 1
rllpf-F T/IMl; 1 » VAL. H L 1 LK 1
SURGE TANK |— SAVE-ALL
r~0.
i
i
713o'n'G 0.5 Tons J 1.181 MG | TANK 0.086 HG PULPER
CLEAR HELL ' 15 Tons
1 SELECT
i WASTE PAPER
f '
0.101 MG TOP LINER 1 I TflP 1 INFR
( ( i 1Q7 Mf "" W.W. TANK | | PULPER
DUMP CHEST
h
n.Ottfi MG |
m-\ TOP LINER
1 DUMP CHEST
IUATER! fo 216 Mt]! t' *
1 \ f 18 Tons
Tj HI-GRADE WASTE
i | PAPF.n-VIRGIN PULF
n.ioi MG ' ^ I
i BROKE |
5 Tons i <
i PAPER HACH NE ' 1 1
DRIER
SECTIDN
PRESS FORM NG 0.843 MG-18.5 Tons
).0?2MG SECTrorj 5FCT ™ 3.935 MG-84 Tons
IUSIons 0.693 HG-15.5 Tons
0.216 MG , < 1
PRODUCT
100 Tons
|
__ 0.101 MG
1 0.66 0 MG
| 1.0 Tons
1 Ton " • 1
0.07? MG : °- ' MG MACHINE SCREENS 1
Ton i i 1
0.283 MG A.
1 'on 3.3 6 MG- 6 Tons
1 .304 Mn t . ._
2 Tons 0.636 MG-1 .5 Tons
"*• I ' *i 4 \ ,
0.713 MG I
.0 Tons 0.069 MG | |
O *
t~ "" 4 Tons
1 .217 HG
I ! ' 3 Tons
7.0 Tons i 1
[TREATMENT
SYSTEM
^Tons
pHiT^ ,m . 7-0 Tons
J 2.0 Tons
^ SCREEN P* °''12 MG
J 6 Tons
1
HEAD BOXES
l_ — 1
MACHINE CHEST
0.101
18 To
HBACK LINER
MACHINE CHEST
^
f1G
s
0.086 MG
15 Tons
0.574 MG
80 Tons
H FILLER
MACHINE CHEST
J Fignr
PROCESS FLOW DI
HASTE PA
L
STOCK
PROCESS WATER
FRESH WATER
6 18
SGRAM AND MATERIALS
]F A
ERBOARD MILL
GEND
EXTENSIVE WATER RE-USE
-------
TABLE 19
PAW WASTE CI^APACTFRISTICS
UNBLEACHED KPAFT - NSCC (CROSS RECOVTRY)
Mill
X -
X -
y _.
X -
X —
x -
x -
x -
X -
X -
1
2
3
4
5
6
7
8
9
10
FLOW
kiloliters/kkg
(1000 gal/ ton)
57.5(13.8)
58.8(14.1)
43.4(10.4)
74.2(17.8)
-
-
-
-
-
-
EOD5
kcr/kkcr
(Ibs/ton)
24(48)
17(33.9)*
16.3(32.6)
-( -)
14(28)
15.5(31)
17.5(35)
21.5(43)
27(54)
42.5(85)
TSS
kcA>-"
(Ibs/ton)
28.5(57)
9.709.4)*
12.5(24.9)
* Primary Treatment Effluent; TSS: NSM.
Notes: Data for mills X - 1 through X - 4 are from rill records of
daily discharge data over one. year's tine. Data for mills
X - 5 through X - 10 are from, mill reports to the MTASI of
annual average waste loads.
73
-------
TABLE 20
PAPERBOARD FROM WASTE PAPER RAW WASTE CHARACTERISTICS
~ Effluent Volume BOD5 ~ TSS*
Kiloliters/kkg kg/kicg kg/kkg
Mill (1000 gal/ton^ Jibs/ton)
__
L-P-1 45.9 (11.0) 78.0 (36) 61.0~(122)
L-P-2 61.9 (16.3) 21.0 (12) 61.5 (123)
L-P-3 35.5 (8.5) 7.5 (15) 43.5 (87)
L-P-4 59.7 (14.3) 11.0 (22) 49.0 (98)
L-P-5 16.7 (4.0) 8.0 (16) 4.0 (8)
L-P-6 45.1 (10.8) 6.5 (13) 10.0 (20)
L-P-7 90.1 (21.6) 7.0 (14) 20.0 (8)
L-P-8 41.7 (10.0) 8.0 (16) 21.0 (42)
L-P-9 83.5 (20.0) 18.0 (36) 14.0 (28)
L-P-10 40.5 (9.7) 10.0 (20) 16.5 (33)
L-P-11 39.6 (9.5) 9.0 (18) 14.0 (28)
L-P-12 41.7 (10.0) 9.5 (19) 9.0 (18)
L-P-13 39.6 (9.5) 37.5 (75) 33.5 (67)
L-P-14 28.0 (6.7) 6.0 (12) 7.0 (14)
L-P-15 62.6 (15.0) 32.5 (67) 53.0 (106)
L-P-16 51.7 (12.4) 11.5 (23) 21.0 (42)
L-P-17 43.0 (10.3) 12.0 (24) 29.5 (59)
L-P-18 13.8 (3.3) 16.0 (32) 10.5 (21)
L-P-19 48.0 (11.5) 6.0 (12) 10.5 (21)
L-P-20 24.2 (5.8) 9.0 (18) 17.0 (34)
L-P-21 65.9 (15.8) 8.0 (16) 13.5 (27)
L-P-22 52.2 (12.5) 21.0 (42) 38.0 (76)
L-P-23 38.8 (9.3) 11.0 (22) 15.0 (30)
L-P-r24 24.2 (5.8) 8.0 (16) 9.0 (18)
L-P-25 55.9 (13.4) 5.0 (10) 10.5 (21)
L-P-26 53.0 (12.7) 12.0 (24) 15.0 (30)
L-P-27 31.3 (7.5) 17.5 (35) 16.5 (33)
L-P-28 80.1 (19.2) 14.5 (29) 20.0 (40)
L-P-29 25.1 (6.6) 23.0 (46) 14.5 (29)
L-P-30 69.3 (16.6) 8.0 (16) 32.5 (65)
L-P-31 54.2 (13.0) 18.0 (36) 20.0 (40)
L-P'32 47.6 (11.4) 11.0 (22) 21.5 (43)
L-P-33 25.0 (6.0) 8.5 (17) 34.0 (68)
L-P-34 39.6 (9.5) 7.0 (14) 16.0 (32)
L-P-35 41.7 (10.0) 12.5 (25) 8.0 (16)
L-P-36 43.4 (10.4) 10.0 (20) 7.0 (14)
L-P-37 35.9 (8.6) 6.0 (12) 7.0 (14)
L-P-38 100.1 (24.0) 12.5 (25) 27.0 (54)
L-P-39 41.7 (10.0) 12.5 (25) 35.0 (70)
L-P-40 43.4 (10.4) 10.0 (20) 8.0 (16)
L-P-41 35.9 (8.6) 6.0 (12) 7.0 (14)
L-P-42 52.2 (12.5) 13.0 (26) 9.0 (18)
*Analytical technique unknown.
74
-------
from data collected by the Michigan Water Resources Commission (34), the
Wisconsin Water Resources Commission (35), and the NCASI (36). The
volume of effluent ranged from 13,760 to 100,150 liters/kkg (3,300 to
24,000 gal/ton) with an average of 45,870 liters/kkg (11,000 gal/ton).
It is known that at three of the mills the effluent has been virtually
eliminated through clarification and water reuse. However, these mills
manufacture a small number of products of coarse grade which makes this
procedure 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 12,510 - 16,680 liters/kkg (3,000-4,000
gal/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 adversely affect the product. Slimicides usage is
likewise limited since some of these also impart odors. Hence, the
minimum practical discharge for a mill producing food board is generally
considered to be about 29,190-41,700 liters/kkg (7,000-10,000 gal/ton).
Practically all products can be produced in this effluent range. As
discussed in Section IV, mills frequently produce food board in
conjunction with non-food board and therefore minimum practical flows
range anywhere from 16,680-41,700 liters/kkg (4000-10,000 gal/ton).
Total suspended solids losses for the 42 mills listed range from 4.0 to
61.5 kg/kkg (8 to 123 Ibs/ton) of product; 27 containing 20 kg/kkg (40
Ibs/ton) or under. The average TSS for the mills in Table 20 was 19.2
kg/kkg (38.4 Ibs/ton) (not including mill L-P-1 and mill L-P-2,
inclusion of which woul'd disproportionately affect the average) . The
identity of the mills in Table 20 is not available and thus the TSS
analytical measurement techniques are unknown. 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 not the most effective type, it
serves to separate usable from unusable fiber and ordinarily restricts
losses to less than 20 kg/kkg (40 Ibs/ton). It also serves to protect
effluent treatment systems from slugs of fiber and clarifiers from
flotation problems.
BOD5 values ranged from 5 to 37.5 kg/kkg (10 to 75 Ibs/ton) of product,
30 of the 42 being less than or equal to 12.5 kg/kkg (25 Ibs/ton).
Residual pulping liquor, starch, and other adhesives, such as glutens,
accounted for most of the BOD5. Raw waste characteristics are also
shown in Table 21 for 23 mills which may be included in Table 20 since
the identification of the mills in Table 20 are not available. The
average BOD5 raw waste load for all mills in Table 21 was 11.25 kg/kkg
(22.5 Ibs/ton) with a range of 4 to 20 kg/kkg (8 to 40 Ibs/ton). The
average BOD5 raw waste load was 12.7 kg/kkg (25.4 Ibs/ton) and 9.0
kg/kkg (1sTo Ibs/ton) for mills P-1 through P-14 and mills P-15 through
P-23, respectively. The TSS raw waste load for mills P-16 through P-23
ranged from 2.8 to 81 kg/kkg (5.6 to 162 Ibs/ton). Effluent flows
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TABLE 21
RAW WASTE CHARACTERISTICS
Mill
P-l
P-2
P-3
P-4
P-5
P-6
P-7
P-8
P-9
P-10
P-ll
P-12
P-13
P-14
P-15
P-16
P-17
P-18
P-19
P-20
P-21
P-22
P-23
PAPERBOARD FROM WASTE PAPER
FLOW
kiloliters/kkg
(1000 gal/ton)
68.4(16.4)
12. 1( 2.9)
19. 6( 4.7)
38. 8( 9.3)
5( 1.2)
47.5(11.4)
9.6(
38. 8(
3)
3)
139.3(33.4)
BODS
kg/kkg
(Ibs/ton)
7.5(15)
15(30)
12(24)
12(24)
13.5(27)
7(14)
5.5(11)
15(30)
12.5(25)
10(20)
18.5(37)
13(26)
16.5(33)
20(40)
16(32)
10(20)
6(12)
5.5(11)**
4( 8)
7.5(15)
9.5(19)
9(18)
12.5(25)
TSS
kg/kkg
(Ibs/ton)
72.5(145)*
9( 18)
35( 70)
4.8(9.5)
6.5( 13)
2.8(5.6)
7.5( 15)
81(162)
*NSM
**Primary Treatment Effluent
Notes: Data for mills P-l through P-14 are from mill reports to the
NCASI of annual average waste loads. Data for mills P-15 through
P-23 are from mill records of daily or weekly discharge data
over one year's time.
76
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averaged 29,940 liters/kkg (7,180 gal/ton) with a range of 5000 to
68,400 liters/kkg (1,200 to 16,400 gal/ton) (not including mill P-23).
Mill P-23 produces all food board and has a correspondingly high flow as
described earlier, of 139,300 liters/kkg (33,400 gal/ton). However, it
is reported that the mill P-23 flow is atypically high and could
possibly be reduced to relatively lower levels without detriment to the
products.
The raw waste load discharged by the mills in this industry is a matter
of some interpretation as the tendency to treat waste water for reuse
prior to biological treatment has become more typical for the industry.
The practice has taken the form of the use of in plant treatment facili-
ties or an out of plant primary clarifier for the removal of suspended
solids from the process white water prior to reuse on the wet end and
other selected areas in the mill. The recovered solids are recycled for
reuse in the stock system in either case and the excess water not
returned to the mill represents the waste volume discharged to
biological treatment or to municipal waste treatment facilities. The
raw waste load attributable to the mills using the above systems is the
volume of waste water after reuse. Those mills that practice only
nominal reuse of process water but 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 reuse. A comparison of the raw waste load of mills using any
one of the three different systems described above in response to their
pollution control problem shows that the primary clarifier effluent of
each is the most equatable parameter. That this is the most
representative raw waste load for a mill is supported by the nearly
industry wide practice of recycling all primary clarifier sludge back to
the process. Under these conditions the clarifier influent does not
represent the actual waste load leaving the mill.
The use of this criterion for defining raw waste loads for mills in this
category becomes more significant when considering the fourth response
to pollution abatement which is receiving wider use in this industry.
This requires the recycle of process water to the extent that the fresh
water use for process purposes equals the evaporation rate from the
process system. The waste water that is generated is both the raw waste
load and final discharge for these mills. This waste is generally the
result of intermittent discharges from holding basins used to contain
the many variables associated with production requirements including
excessive stock dumps, grade changes, or mill wash ups. Achievement of
this goal is made by differing routes. One approach utilizes a well
designed in-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 industry which have been built within the last ten years that
have designed into the process plans at the engineering stage the
concept of complete process water recycle. This approach utilizes one
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or the other of both solids removal systems described above and includes
extensive noncontact cooling water collection and recycled fresh water
systems used in noncontaminating areas and discharged separately to the
environment without treatment. In addition, selective process water use
and recycle practices are designed into the plant at the engineering
phase. One such mill was included in 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 on the final discharge, however, the waste load
discharged to the environment was significantly lower than the discharge
from mills with primary settling and biological treatment facilities.
Using data obtained at mills practicing all four methods of treatment
and recycle, the following comparisons can be made. The BOD5 of the
discharge by mills with secondary treatment facilities averaged 0.65
kg/kkg (1.3 Ibs/ton) and that for the mill without biological treatment
but with near complete recycle achieved 0.075 kg/kkg (0.15 Ibs/ton) BOD5_
and far lower waste loads than achieved by the other mills in total
suspended solids. However, for this mill the concentrations of
contaminants were considerably higher in the final discharge to the
environment. Perhaps more importantly the concentrations of dissolved
solids attributable to the extensive recycle of process water reached
significantly high levels, 1800 mg/1 BOD5 and 7500 mg/1 total dissolved
solids (TDS), which this particular production process was able to
tolerate.
Evaluation of the results obtained by the four basic approaches made by
this industry to the pollution control effort supports the fact that the
waste waters generated respond well to the biological treatment process
for the reduction of BOD5 and to a lesser extent, except with near
complete recycle, dissolved solids. The waste is generally deficient in
phosphorus and nitrogen making necessary the addition of nutrients to
achieve good biological treatment performance and is low in heavy metals
concentration, rarely exceeding one mg/1.
These wastes are substantially neutral although some grades of paper
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
relatively 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.
The turbidity varies over a wide range depending on the production grade
being run in the mill. However, evaluation of the data obtained during
the survey program carried out at mills in this subcategory demonstrates
that clarification followed by biological treatment reduces the
turbidity from 200 to 700 JTU (Jackson Turbidity Units) to 15 to 35 JTU.
It can be concluded that the installation of treatment facilities for
the reduction of BOD5 will generally reduce turbidity to acceptable
levels.
78
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Historically, the raw waste water for mills in this industry 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 the reuse factor
becomes paramount when characterizing the waste loads discharged to the
environment on an industry-wide basis.
There are other factors that exert an adverse influence on the quantity
and quality of the waste water generated by paperboard from waste paper
mills on an intermittent basis. Virtually all mills change from one
grade of product to another during an operating cycle. The frequency of
this occurrence varies from two or three changes in a 24-hour period to
only once in three or four days. The effect on the waste water
generated may be negligible or quite obvious, depending on the
difference in the grade change being made. Generally the suspended
solids increases with an attendant increase in BODJ5. The duration of
this import is from perhaps 15 minutes to one hour after which the waste
stream returns to normal conditions. Production scheduling generally
avoids following a production grade with a completely different grade in
order to reduce the interim period of production that meets neither
grade specification. This, therefore, tends to minimize the impact of
grade change on waste water quality except where it is unavoidable.
Mill washups occur perhaps once a week; however, in recent years many
mills have extended their operating period to 14 and 21 day cycles.
This extended period frequently coincides with a felt or wire life cycle
which permits a felt or wire to be changed during a scheduled mill
shutdown. A mill shut down largely influences the suspended solids
content of the waste stream. These solids have accumulated in various
tanks and chests throughout the process system over the operating cycle
and are generally considered to be undesirable for return to the
production process. Some mills reuse a substantial amount of the solids
generated by a washup, others reuse virtually none. In either case the
primary clarifier removes these solids from the waste stream and the
excess is disposed of via the clarifier underflow system to sludge
dewatering ponds or vacuum filtration prior to land disposal.
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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 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
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, however, 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 BOD5_ 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, BOD5_ 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 performance of the
mill waste treatment facilities is not documented, however. Since
treatment capabilities are a function of time and kilograms 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.
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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.
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TABLE 22
SUMMARY
RAW WASTE CHARACTERISTICS
FLOW
Subcategory
Unbleached
Kraft
NSSC-
co Ammonia
ro
NSSC-
Sodium
Kraft-
NSSC
Paperboard
Waste Paper
kiloliters/kkg
(1000 gal/ ton)
Range
39.2-85.5
(9.4-20.5)
_ '
(-)
20.0-106.7
(4.8-25.6)
43.4-74.2
(10.4-17.8)
5.0-68.4
(1.2-16.4)
Ave
52.5
(12.6)
34.8
(8.3)
42.9
(10.3)
58.4
(14.0)
29.9
(7.2)
BOD5
kg/kkg
(Ibs/ton)
Range
12-28
(24-56)
_
(-)
11-45
(22-90)
14-27
(28-54)
4-20
(8-40)
Ave
16.9
(33.8)
33.5
(67.0)
25.2
(50.4)
19.4
(38.8)
11.2
(22.5)
TSS
kg/kkg
(Ibs/ton)
Range
19-28
(38-56)
_
(-)
4-23
(8-46)
12.4-28
(24.9-57)
2.8-81
(5.6-162)
Ave
21.9
(43.8)
17*
(34)*
12.3**
(24.6)**
20.5
(41)
(-)
*NSM
**TSS Analytical Technique unknown
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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 all of the other sources discussed
previously demonstrates that the following constituents represent
pollutants according to the Water Pollution Control Act for the
subcategories under study:
Biochemical Oxygen Demand (5-day, 20°C)(BOD5)
Total Suspended Solids
PH
Color (Not including Paperboard from Waste Paper)
Ammonia Nitrogen (NSSC-Ammonia base only)
RATIONALE FOR SELECTION OF IDENTIFIED PARAMETERS
Biochemical Oxygen Demand (5-day, 20°C) (BOD5)
Biochemical oxygen demand (BOD) is a measure of the oxygen consuming
capabilities of organic matter. The BODJj in pulp and paper mill
effluents is a result of the various pulp and paper making processes as
shown in Sections III and V. The BOD5 does not in itself cause direct
harm to a water system, but it does exert an indirect effect by
depressing the oxygen content of the water. Sewage and other organic
effluents during their processes of decomposition exert a BOD£, which
can have a catastrophic effect on the ecosystem by depleting the oxygen
supply. Conditions are reached frequently where all of the oxygen is
used and the continuing decay process causes the production of noxious
gases such as hydrogen sulfide and methane. Water with a high BOD£
indicates the presence of decomposing organic matter and subsequent high
bacterial counts that degrade its quality and potential uses.
Dissolved oxygen (DO) is a water quality constituent that, in
appropriate concentrations, is essential not only to keep organisms
living but also to sustain species reproduction, vigor, and the
development of populations. Organisms undergo stress at reduced DO
concentrations that make them less competitive and able to sustain their
species within the aquatic environment. For example, reduced DO
concentrations have been shown to interfere with fish population through
delayed hatching of eggs, reduced size and vigor of embryos, production
of deformities in young, interference with food digestion, acceleration
of blood clotting, decreased tolerance to certain toxicants, reduced
food efficiency and growth rate, and reduced maximum sustained swimming
speed. Fish food organisms are likewise affected adversely in
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conditions with suppressed DO. Since all aerobic aquatic organisms need
a certain amount of oxygen, the consequences of total lack of dissolved
oxygen due to a high BOD5 can kill all inhabitants of the affected area.
If a high BOD5 is present, the quality of the water is usually visually
degraded by the presence of decomposing materials and algae blooms due
to the uptake of degraded materials that form the foodstuffs of the
algal populations.
Total Suspended Solids (TSS^
Total suspended solids (or suspended solids) is a measure of
nondissolved solids in the waste water which are trapped or "suspended"
on a test filter medium. Suspended solids in pulp and paper mill
effluents are generally fibrous materials lost in the pulping of wood
and production of paper. Most of these suspended solids can be removed
by primary treatment with most of the remainder removed by secondary
treatment. The suspended solids discharged from pulp and paper mill
secondary treatment systems are generally biological organisms generated
in the secondary treatment system in the removal of BOD5, and thus are
not characteristic of the suspended solids in the raw waste. The
biological suspended solids in pulp and paper mill effluents have the
following detrimental effects upon receiving waters: (1) increases in
turbidity of the receiving water resulting in reduced light transmission
and accompanying effects, such as reduced photosynthesis, (2)
degradation of aesthetic values, (3) settling of suspended solids to the
bottom of receivng waters, and (H) exertion of BOD by the biological
suspended solids. The BOD exerted by the biological suspended solids is
only partially measured by the BOD.5 test as the BOD2C) would be more
descriptive of the oxygen consuming effects. A general description of
suspended solids and effects upon receiving waters is given below.
Suspended solids include both organic and inorganic materials. The
inorganic components include sand, silt, and clay. The organic fraction
includes such materials as grease, oil, tar, animal and vegetable fats,
various fibers, sawdust, hair, and various materials from sewers. These
solids may settle out rapidly and bottom deposits are often a mixture of
both organic and inorganic solids. They adversely affect fisheries by
covering the bottom of the stream or lake with a blanket of material
that destroys the fish-food bottom fauna or the spawning ground of fish.
Deposits containing organic materials may deplete bottom oxygen supplies
and produce hydrogen sulfide, carbon dioxide, methane, and other noxious
gases.
In raw water sources for domestic use, state and regional agencies
generally specify that suspended solids in streams shall not be present
in sufficient concentration to be objectionable or to interfere with
normal treatment processes. Suspended solids in water may interfere
with many industrial processes, and cause foaming in boilers, or
encrustations on equipment exposed to water, especially as the
temperature rises. Suspended solids are undesirable in water for
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textile industries; paper and pulp; beverages; dairy products;
laundries; dyeing; photography; cooling systems, and power plants.
Suspended particles also serve as a transport mechanism for pesticides
and other substances which are readily sorbed into or onto clay
particles.
Solids may be suspended in water for a time, and then settle to the bed
of the stream or lake. These settleable solids discharged with man's
wastes may be inert, slowly biodegradable materials, or rapidly
decomposable substances. While in suspension, they increase the
turbidity of the water, reduce light penetration and impair the
photosynthetic activity of aquatic plants. Solids in suspension are
aesthetically displeasing. When they settle to form sludge deposits on
the stream or lake bed, they are often much more damaging to the life in
water, and they retain the capacity to displease the senses. Solids,
when transformed to sludge deposits, may do a variety of damaging
things, including blanketing the stream or lake bed and thereby
destroying the living spaces for those benthic organisms that would
otherwise occupy the habitat.
When of an organic and therefore decomposable nature, solids use a
portion or all of the dissolved oxygen available in the area.
pH, Acidity, and Alkalinity
The effluent from a typical biological treatment process will normally
have a pH in the range of 6.0 to 9.0, which is not detrimental to most
receiving waters. However, the application of some technologies at pulp
and paper mills for the removal of color, solids, and nitrogen can
result in major adjustments in pH. The effluent limitations which are
cited insure that these adjustments are compensated prior to final
discharge of treated wastes in order to avoid harmful effects within the
receiving waters. A general description of pH, acidity, and alkalinity
and their effects upon receiving waters follows.
Acidity and alkalinity are reciprocal terms. Acidity is produced by
substances that yield hydrogen ions upon hydrolysis and alkalinity is
produced by substances that yield hydroxyl ions. The terms "total
acidity" and "total alkalinity" are often used to express the buffering
capacity of a solution. Acidity in natural waters is caused by carbon
dioxide, mineral acids, weakly dissociated acids, and the salts of
strong acids and weak bases. Alkalinity is caused by strong bases and
the salts of strong alkalies and weak acids.
The term pH is a logarithmic expression of the concentration of hydrogen
ions. At a pH of 7, the hydrogen and hydroxyl ion concentrations are
essentially equal and the water is neutral. Lower pH values indicate
acidity while higher values indicate alkalinity. The relationship
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between pH and acidity or alkalinity is not necessarily linear or
direct.
Waters with a pH below 6.0 are corrosive to water works structures,
distribution lines, and household plumbing fixtures and can thus add
such constituents to drinking water as iron, copper, zinc, cadmium and
lead. The hydrogen ion concentration can affect the "taste" of the
water. At a low pH water tastes "sour". The bactericidal effect of
chlorine is weakened as the pH increases, and it is advantageous to keep
the pH close to 7. This is very significant for providing safe drinking
water.
Extremes of pH or rapid pH changes can exert stress conditions or kill
aquatic life outright. Dead fish, associated algal blooms, and foul
stenches are aesthetic liabilities of any waterway. Even moderate
changes from "acceptable" criteria limits of pH are deleterious to some
species. The relative toxicity to aquatic life of many materials is
increased by changes in the water pH. Metalocyanide complexes can
increase a thousand-fold in toxicity with a drop of 1.5 pH units. The
availability of many nutrient substances varies with the alkalinity and
acidity. Ammonia is more lethal with a higher pH.
The lacrimal fluid of the human eye has a pH of approximately 7.0 and a
deviation of 0.1 pH unit from the norm may result in eye irritation for
the swimmer.
Color is defined as either "true" or "apparent" color. In Standard
Methods for the Examination of Water and Wastewater (U) , the true color
of water is defined as "the color of water from which the turbidity 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 lignin derivatives are
solubilized 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.
Color has the following detrimental effects upon receiving waters: (1)
color retards sunlight transmission and interferes with photosynthesis
thereby reducing the productivity of the aquatic community; (2) color
alters the natural stream color which detracts from the visual appeal
and recreational value of the receiving waters; (3) color has effects
upon downstream municipal and industrial water users, such as higher
water treatment costs, difficulties in water treatment, and a multitude
of industrial process operating problems; (4) color bodies complex with
metal ions, such as iron or copper, forming tar-like residues which
remove the metals from the stock available to stream organsims for
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normal metabolism, and the complexes can have direct inhibitory effects
on some of the lower scale of organisms in the aquatic community and
thereby reduce the productivity of the receiving water; (5) color,
derived from lignin, is an indicator of the presence of potentially
inhibitory compounds and in addition may have direct inhibitory effects
upon some of the lower scale organisms in the food chain, (6) color in
receiving waters affects fish movements and fish productivity, and (7)
color bodies exert a long term BOD (20-60 days up to 100 days) not
measured by the BOD5 test.
Color limitations in Sections X and XI are for color as measured by the
techniques specified in NCASI Technical Bulletin *253 (December 1971)
(See Appendix V) (2).
Ammonia Nitrogen
Nitrogen is a nutrient which can contribute to 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. 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 detrimental to
receiving waters. A general description of ammonia nitrogen and the
detrimental effects to receiving waters is given below.
Ammonia is a common product of the decomposition of organic matter.
Dead and decaying animals and plants along with human and animal body
wastes account for much of the ammonia entering the aquatic ecosystem.
Ammonia exists in its non-ionized form only at higher pH levels and is
the most toxic in this state. The lower the pH, the more ionized
ammonia is formed and its toxicity decreases. Ammonia, in the presence
of dissolved oxygen, is converted to nitrate (NO3) by nitrifying
bacteria. Nitrite (NO2), which is an intermediate product between
ammonia and nitrate, sometimes occurs in quantity when depressed oxygen
conditions permit. Ammonia can exist in several other chemical
combinations including ammonium chloride and other salts.
Nitrates are considered to be among the poisonous ingredients of
mineralized waters, with potassium nitrate being more poisonous than
sodium nitrate. Excess nitrates cause irritation of the mucous linings
of the gastrointestinal tract and the bladder; the symptoms are diarrhea
and diuresis, and drinking one liter of water containing 500 mg/1 of
nitrate can cause such symptoms.
Infant methemoglobinemia, a disease characterized by certain specific
blood changes and cyanosis, may be caused by high nitrate concentrations
in the water used for preparing feeding formulae. While it is still
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impossible to state precise concentration limits, it has been widely
recommended that water containing more than 10 mg/1 of nitrate nitrogen
(NO3-N) should not be used for infants. Nitrates are also harmful in
fermentation processes and can cause disagreeable tastes in beer. In
most natural water the pH range is such that ammonium ions (NHU+)
predominate. In alkaline waters, however, high concentrations of un-
ionized ammonia in undissociated ammonium hydroxide increase the
toxicity of ammonia solutions. In streams polluted with sewage, up to
one half of the nitrogen in the sewage may be in the form of free
ammonia, and sewage may carry up to 35 mg/1 of total nitrogen. It has
been shown that at a level of 1.0 mg/1 un-ionized ammonia, the ability
of hemoglobin to combine with oxygen is impaired and fish may suffocate.
Evidence indicates that ammonia exerts a considerable toxic effect on
all aquatic life within a range of less than 1.0 mg/1 to 25 mg/1,
depending on the pH and dissolved oxygen level present.
Ammonia can add to the problem of eutrophication by supplying nitrogen
through its breakdown products. Some lakes in warmer climates, and
others that are aging quickly are sometimes limited by the nitrogen
available. Any increase will speed up the plant growth and decay
process.
RATIONALE FOR PARAMETERS NOT SELECTED
Settleable Solids
Settleable solids are a measure of that fraction of suspended solids
which settles after one hour in a quiescent vessel. While a few mills
have measured Settleable solids, reliable data are not generally or
widely available. Since Settleable solids are measured as a part of the
suspended solids, settleable solids are not considered a separate
pollutant.
Turbidity
Turbidity is an expression of the optical property of the fine suspended
matter in a sample of water. The suspended matter may be clay, silt,
finely divided organic and inorganic matter, plankton, and other
microscopic organisms. The suspended matter causes light to be
scattered and absorbed rather than transmitted in straight lines through
the sample. The paperboard from waste paper subcategory has been
reported having mill effluents which may have high turbidities.
However, turbidity is not considered as a pollutant parameter because
treatment systems installed to reduce BOD5 will also reduce turbidity.
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Coliform Organisms
The fecal coliform test is the most valid microbiological parameter for
pulp and paper effluents presently available. The excessive densities
of fecal coliforms and more specifically, Klebsiella pneumoniae, as
measured by the fecal coliform test, in pulp and paper mill effluents
are significant. Klebsiella can complicate E. coli detection, they can
be pathogenic, and they are coliforms by definition. In addition,
Klebsiella are found in the intestinal tract of approximately 30% of
humans and 40% of animals. Klebsiella reflect the high nutrient levels
in pulp and paper mill wastes. With adequate treatment for reduction of
nutrients, densities of Klebsiella and also total coliforms should be
significantly reduced.
Coliforms are not included as a separate pollutant parameter because (1)
an adequate data base is lacking for the pulp and paper industry, (2)
adequate biological treatment should reduce fecal coliform levels to
less than 1000/100 mis, and (3) disinfection techniques for reduction of
coliforms in pulp and paper mill effluents may be more harmful to the
environment than the coliforms. A general description of coliforms is
given below.
Fecal coliforms are used as an indicator since they have originated from
the intestinal tract of warm blooded animals. Their presence in water
indicates the potential presence of pathogenic bacteria and viruses.
The presence of coliforms, more specifically fecal coliforms, in water
is indicative of fecal pollution. In general, the presence of fecal
coliform organisms indicates recent and possibly dangerous fecal
contamination. When the fecal coliform count exceeds 2,000 per 100 ml
there is a high correlation with increased numbers of both pathogenic
viruses and bacteria.
Many microorganisms, pathogenic to humans and animals, may be carried in
surface water, particularly that derived from effluent sources which
find their way into surface water from municipal and industrial wastes.
The diseases associated with bacteria include bacillary and amoebic
dysentery. Salmonella gastroenteritis, typhoid and paratyphoid fevers,
leptospirosis, chlorea, vibriosis and infectious hepatitis. Recent
studies have emphasized the value of fecal coliform density in assessing
the occurrence of Salmonella. a common bacterial pathogen in surface
water. Field studies involving irrigation water, field crops and soils
indicate that when the fecal coliform density in stream waters exceeded
1,000 per 100 ml, the occurrence of Salmonella was 53.5 percent.
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Resin Acids
Soaps of resin acids (isopimaric, abietric, and dehydroabietric) have
been identified as causing 80 percent of the biologically deleterious
effects of unbleached kraft mill effluent. Studies in Canada indicates
that these compounds are contained mainly in combined condensates rather
than black liquor. The most recent studies indicate that a reduction in
biologically deleterious effects can be achieved by a well designed and
operated biological treatment system. This parameter is not considered
as a separate pollutant parameter for any of the subcategories because
adequate biological treatment systems generally will reduce resin acids.
However, data are lacking to determine the extent of the reductions.
Polychlorinated Biphenvls
Polychlorinated biphenyls (PCB's) are chemically and thermally stable
compounds found in paper and paperboard manufacture and are known to
cause deleterious effects upon biological organisms. They have been
shown to concentrate in food chains and few restrictions on their
control exist at present. Recycled office papers are the main source in
the paper industry at present, although occasionally paperboard extracts
show evidence of Monsanto1s Aroclor 1254 (PCB) from environmental and
other sources. Quantities of PCB in recycled paperboard are generally
between 1 and 10 mg/1, but may be more or less. Functional barriers or
lines in paperboard are seen to provide food stuff protection until
PCB's are purged from the system through process waters, volatilization
and paper destruction. This parameter is not considered as a separate
pollutant parameter for any of the subcategories because an adequate
data base does not exist.
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SECTION VII
CONTROL AND TREATMENT TECHNOLOGIES
Waste water effluents discharged from the subject subcategories of the
industry to receiving waters can be reduced to required levels by
conscientious application of established in-plant process control
together with water recycle measures and by well designed and operated
external treatment facilities. Present technology will not allow
achievement of zero discharge.
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 for each of the subcategories. In
some cases the "in-plant" and "external" technologies merge. For
example, a mill may employ extensive suspended solids removal equipment
internally, 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.
Tables 23 and 24 summarize internal and external alternative
technologies which are in present use or under development.
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Table 23
SUMMARY OF INTERNAL TECHNOLOGIES
Subcateqorv
Unbl. NSSC
Kraft Ammon.
Paperboard
NSSC Kraft- from
Sodium _NSS_c_ Waste Paper
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
I. PULP MILL
A. General
Gland water reduction/reuse
Vacuum pump seal water
reduct ion/r eus e
Internal spill collection
B. Wood Handling
Dry Handling
Wet Handling with recycle
C. Digestion S Pulp Washing
Hot stock screening
Knot removal and/or reuse
Wash water reuse
D. Spent Cooking Ligugrs
Chemical recovery
Land disposal or sale
Condensate reuse
Dregs recovery
II. PAPER_MILL
Reuse of white water
Saveall system
Shower water reduction/reuse
Gland water reduction/reuse
Vacuum pump seal water
reduction/reuse
Internal spill collection
Note: Data were generally not available to accurately determine
the percentage use by mills in each subcategory of the
internal technologies.
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
92
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Table 24
SUMMARY,OF EXTERNAL TECHNOLOGIES
I Technologies in general use.
BASIC FUNCTION
Screening
Neutralization
Suspended Solids
Removal
BODS removal
Foam control
ALTERNATIVE TECHNOLOGIES
Traveling, self-cleaning
Fixed bars
Automatic pH control
Manual pH control
Mechanical Clarifier (C)
Earthen Basin (L)
Dissolved Air Flotation (DAF)
Aerated Stabilization Basin (ASB)
Activated Sludge (AS)
Storage oxidation (SO)
Chemical
Mechanical
Estimated percentage use of above alternatives by subcategory:
TECHNOLOGY
(C)
(L)
(DAF)
(ASB)
(AS)
(SO)
UNBLEACHED
KRAFT,
50
30
*10
50
*10
45
NSSC
AMMONIA
50
*10
10
50
*10
*10
NSSC
SODIUM
20
10
10
40
*10
*10
KRAFT
NSSC
80
10
10
60
*10
40
PAPERBOARD
FROM
WASTE^PAPER
80
15
*10
30
30
*10
* means "less than"
Note: Mills discharging into public sewers are excluded from above
percentage estimates.
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Table 24 (Cont'd)
II Advanced technologies.
BASIC FUNCTION ALTERNATIVE TECHNOLOGIES
Color removal Lime treatment
Activated carbon
Coagulation-alum
Reverse osmosis
Suspended Solids Removal Filtration (i.e. sand or multi-media)
III Color Removal Technologies - Stage of Development
Treatment Type of Installation
Lime Treatment Full Scale
Activated Carbon Pilot Scale
Coagulation - Alum Full Scale
Reverse Osmosis Full Scale
Resin Adsorption Full Scale
Ultrafiltration Pilot Scale
Amine Treatment Bench Scale
Ion Flotation Bench Scale
UNBLEACHED KRAFT
Internal Technologies:
Available methods for reduction of pollutant discharges by internal
measures include effective pulp washing, chemicals and fiber recovery,
treatment and reuse of selected waste streams and collection of spills
and prevention of "accidental" discharges. Internal measures are
essentially reduction of pollutant discharges at their origin and result
in recovery of chemicals, by-products, and in conservation of heat and
water.
Generally, mills which reduce raw waste pollutant loads concomitantly
reduce effluent flowage through recycle. An example selected from two
surveyed unbleached kraft mills illustrates this point. The raw waste
BOD5 load of one such mill was 22.5 kg/kkg (45 Ibs/ton) using 58,422
liters/kkg (14,000 gal/ton). The effluent of- the second mill contained
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only 17 kkg/kkg (34 Ibs/ton) of BOD5 at a 41,731 liters/kkg (10,000
gal/ton)flow.
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, the BOD5 and suspended solids losses are not a
major percentage of the total waste, as pointed out in Section V.
However, as mills reduce their raw waste loads through internal
controls, the waste loads from wet barking may become more significant
as it will be a larger percentage of the total waste load. Elimination
of raw waste loads from wet barking can be achieved through total
recycle of the barking water. A closed system for wet barking installed
at a mill in California completely is presently very near to a
successful closed system.
Treatment of wet barking effluents consists of screening followed by
settling to remove fine suspended solids (principally silt). Heavy duty
mechanically-raked clarifiers 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 (12) .
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/kkg (0.2 to 0.4 gal/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.
The water removed by the decker typically accounted for about one-third
of the total BOD.5 loss from the mill.
Normal practice now 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 specially designed hot stock screen which effectively
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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 as raw waste loads are substantially reduced. 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-
slaking 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.
Kraft mill condensates are recognized to be the principal BOD
contributors to the effluent load from unbleached kraft mills.
Consequently, considerable effort has been spent by most kraft
operations to consume internally as much of these condensates as
possible by substituting them for normal fresh water make-up
applications. Most commonly the recycling of condensates has occurred
in brown stock washing and in causticizing make-up. Use of condensates
in stack scrubbers for lime kilns and disolving tank vents is also a
common practice. Direct disposal of condensates has been successfully
accomplished by large scale spray irrigation in locations where suitable
soil and groundwater conditions are available.
Despite the extensive condensate recycling practices, these waste
streams still constitute, collectively, a most serious source of air and
water pollution from unbleached kraft operations.
Many of the problems related to condensates evolve from the recycling
practices themselves. Ideally, recycling of waste streams assumes that
the waste stream is totally consumed in the process - that the polluting
materials are destroyed by incineration or homogeneously assimilated
into the process streams. This of course is not entirely correct when
speaking of condensates. Since condensates in general are black liquor
distillates, a large fraction of the offending chemical substances
involved are volatile substances which are not amenable to the basic
black liquor processing scheme. If this were not so, the materials
would not have distilled during the formation of the condensate stream.
Recycling the condensate may result in a gradual increase in the
concentration of the volatiles in the process stream involved.
Consequently, distillate slip streams from the process may become
enriched with these volatiles to the extent that serious air and water
pollution problems occur in areas where no serious problems exist
without the recycling practices. The observed increase 4n &°®
concentration of multi-effect evaporator condensate with extensive
recycling of condensates to brown stock washers may serve as an example.
Recycling of condensates to the causticizing system may also result in
similar problems. Elevated temperatures at the recovery dissolving
tank, slaking and causticizing area, and lime kiln area, may provide a
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means for purging recycled volatiles from condensates to the atmosphere.
Since many of these volatiles are malodorous, it is obvious that the
kraft mill odor problem may be greatly enhanced by the recycling
practice. Normally innocuous emission sources, such as tank vents and
vacuum pump exhausts, may also become fortified through extensive
condensate recycling.
Operational problems may also occur with extensive condensate recycling.
Increased wet strength additive usage has been linked with the
application of multi effect evaporator condensate on brown stock
washing. Momentary black liquor carry-over in condensate streams
recycled to the causticizing area may seriously disrupt the normal
liquor-making process. Unquestionably, many of the side effects of the
recycling practices have yet to be defined.
For a large part the condensate streams from the continuous pulping
process differs markedly from the batch process. The continuous
digester blow generally occurs at a lower temperature and pressure than
that of the batch cook. The evolution of distillates in this function
is inconsequential in comparison to the batch counterpart. Relief
condensate, characteristic of the batch cook, does not occur as such in
the continuous cook. However, condensate from continuous digester
steaming vessels may be compared with the batch relief condensate.
Condensates from the recovery system evaporators and from condensed blow
tank vapors account for about one-third of the total BODS. Table 25
shows typical reuse points for these condensates. Methanol accounts for
about 80 percent of their organic content and for most of the BOD5 (38) .
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 (37) (38) (39).
Steam stripping has been successfully applied at least at one bleached
kraft mill, and another is planning to air strip condensates. It should
be noted that this technology is transferable from bleached to
unbleached kraft mills.
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TABLE 25
REUSE OF EFFLUENT FROM DIFFERENT UNIT OPERATIONS
Kiloliters/kkg
Type of Effluent (gal/ton) Place of Reuse
Blow gas condensate,
direct
Blow gas condensate,
indirect
Cooling-water for
blow-gas condenser,
indirect
Turpentine-decanter
underflow
Cooling water for
turpentine condenser
Evaporator
condensate
Evaporator
barometric
effluent
Cooling water for
evaporator surface
condensers
Evaporator seal
pit, discharge
from surface condensers
5.7 - 22.H
(1500-5900)
Average
8.6 (2000)
1133 - 1.52
(350 - 400)
1500 - 5900
Average:
8.6 (2000)
0.038 - 0.63
(10 - 165)
Average:
0.19 (50)
2.U7 - 9.12
(675 - 2440)
2.56 - 10.6
(675 - 2800)
Average:
about
5.7 - 7.6
30.« - 57.0
(8000 - 150CO)
1.52 - 5.89
(HOO - 1550)
Brown stock washing
Screen room or decker
operation
Hot water supply
Mud Washing
Dissolving of additives
None (Sewered)
Hot water supply
Brown stock washing
Bleached stock washing
Screen room or decker
operation
Showers on knotter
Showers on brown-stock
washers
Hot water supply
Screen room
Boiler make-up water
Direct blow-heat condenser
Brown stock washing
Lime kiln scrubber
Cooking liquor preparation
Mud-washing or dreg washing
Woodyard, Wash-ups, Sewer
Boiler make-up water
Transport of bark-boiler
fly ash
Recycled through
cooling-tower
Hot water supply
Machine showers in
paper mill
Brown stock washing
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A rule of thumb sometimes used in the industry is that one-third to one-
half of the BOD5 and 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. The mill experienced an unusual short-term
black liquor loss. This caused raw waste BOD5 to increase from 17 to 29
kg/kkg (34 to 58 Ibs/ton Suspended solids increased from 11 to 18.5
kg/kkg (22 to 29 Ibs/ton). Such shock loads can interfere 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. It should be noted that in the 1950's the flushed
material was usually sewered, but presently most operations have the
capability of returning the material to the liquors from the pulp
washing system or to a special storage tank from where the material
can be returned to the process (40).
2. Storage facilities should be provided for weak black liquor,
strong black liquor, and recovery plant chemicals and liquors.
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 originating subprocess at a later time.
3. if overflows would cause treatment plant upset or increased
discharge of pollutants, production curtailments should be made as
required to avoid overflows if the overflows cannot be prevented by
some other means. Sewer segregation can be utilized, especially in
new mills, to minimize these impacts, in conjuction with adequate
storage.
4. Continuous monitoring within mill sewers (especially conduc-
tivity) should be employed to give immediate warning of unknown
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.
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6. Storage lagoons located prior to biological treatment should be
provided to accept longer term shock loads. The contents can then
be gradually returned to process or to treatment without detriment
to treatment operations.
In the stock preparation paper machine systems large quantities of water
are necessary to form a sheet of paper. Typically, the fibrous stock is
diluted to about 0.5 percent consistency before entering the paper
machine itself. Such dilutions are necessary 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 smoothness. 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-belt
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 60 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/kkg (25,000 gal/ton). Due to recycling,
only a relatively small portion of the total is wasted. Mills which
utilize varying amounts of extensive recycling discharge only 2,087 to
20,865 liters/kkg ton (500 to 5000 gal/ton) white water 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
loads 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 Section
V. In the last 10 years, further strides in reuse have been made.
100
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Problems associated with increased reuse usually manifest themselves in
reduced machine speed and/or product quality. Slime growth due to in-
crease of BOD5 and temperature has been encountered. This problem can
be reduced by the proper application of biocides, 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
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. In addition, corrosion is a
significant factor in increased recycling within the white water system.
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
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 addition of air under pressure, attach themselves
to the fibers, causing them to float to the surface, 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 provides
a positive barrier for fibers preventing their introduction into the
clarified white water. DAF units are still popular, however, in
paperboard from waste paper mills.
Clarified effluent from save-alls is on the order of 10,433-25,038
liters/kkg (2900-6000 gal/ton) (19), 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 (19) :
101
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1. Vacuum pump seals
2. Machine showers
3. stock cleaner elutriation
4. Cooling waters
5. Pulp washing
6. Wash-ups
7. Consistency regulation dilution
8. Barometric evaporator condensers (pulp mill)
9. Repulping of broke and purchased fiber
Vacuum pumps are utilized in paper mills to provide a vacuum source to
accelerate the removal of water from fourdrinier machines, presses,
save-alls, and other devices and thus the vacuum pump demand for water
is somewhat product dependent. Most such pumps are of the ring seal
type, which require large amounts of water. This water provides a seal
between 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/kkg (2500 to 4000 gal/ton). It must be
sufficiently free of suspended solids to avoid plugging of the orifices
or other control devices used to meter it to the pump. The formation of
scale inside of the pumps can be a problem. 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 extensive recycling 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
is an area which requires more study and development.
Presently, 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 is 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/kkg (1000-2000 gal/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
102
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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 purpose. In recent years, attention has focused on the use of
recycled white water on showers, and this trend has increased with the
development of self-cleaning showers. Even with self-r 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 possible 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,
usually 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
efficiency through a continuous discharge of reject although significant
quantities of usable fiber are also rejected. To reduce such losses,
the cleaners are usually arranged in stages, so that rejects from
previous stages are sent through subsequent stages of smaller size. Re-
jects from the last stage have a consistency 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, elutriation 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-friction 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-
103
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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
mill surveyed returned dryer condensate directly to the feed water heat-
er at the boiler plant under 1.20-1.34 atm 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).
External Technologies
External control technologies for the treatment of unbleached kraft
effluents are discussed below. Specifically, these technologies include
technologies for reduction of suspended solids, BODS, and color. Data
on eleven unbleached kraft mills which have secondary treatment and for
which secondary treatment effluent data were available are shown in
Tables 26 and 27. Specifically, Table 26 shows production, flow, type
of treatment, and the TSS analytical measurement technique for each
mill. Table 27 shows BOD.5 and TSS data for the mills' raw waste and
final effluents (Note: AA is the annual average of daily values and MM
is the maximum monthly average of daily values). The data generally
represent a full year's operation and have been derived from mill
records by either EPA or the NCASI.
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 clarifiers, 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 (12) .
Dissolved air flotation has been applied to effluents from paperboard
from waste paper mills and has achieved removal efficiencies of up to
98 percent of the suspended solids (Ul). The relatively high cost of
flotation equipment, its requirements for flocculating chemicals, high
power requirements, and mechanical complexity make it unsuitable for
application in other than the capacity of a save-all, except where space
104
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TABLE 26
MILL DATA
UNBLEACHFD KRAFT
Mill
UK-1
UK-2
UK-3
UK-4
UK-5
(JK-6
UK-7
UK-8
UK-9
UK-10
UK-11
Production-AA
kkg/day
(tons/day)
1020 (1125)
824 ( 909)
794( 875)
751( 828)
1201(1324)
732( 807)
641( 707)
997(1099)
1376(1517)
1464(1614)
346 ( 382)
Flow-AA
kiloliters/kkg
(1000 gal/ton)
39.2
50
39.6
85.5
60
64.2
112.5
43.4
43.4
55.5
43.8
(9.4)
(12.0)
( 9.5)
(20.5)
(14.4)
(15.4)
(27.0)
(10.4)
(10.4)
(13.3)
(10.5)
Treatment
Methods
ASB
ASB-SO
ASB-SO
ASB-SO
ASB
ASB-SO
ASB-SO
SO
ASB
ASB-SO
ASB-SO
TSS
Methods
SM*
SM*
SM
SM
SM
SM
SM
SM
NSM
NSM
SM
* Final effluents: SM, raw waste: NSM
-------
TABLE 27
Mill
UK-1
UK-2
UK-3
UK-4
UK-5
UK-6
UK-7
UK-8
UK-9
UK-10
UK-11
MILL EFFLUENT DATA
UNBLEACHED KRAFT
(All values in kg/kkg (Ibs/ton) except as noted)
Raw Waste
Final Effluent
AA
BODb
13.5(27)
12.2(24.5)
14(28)
15.5(31)
19(38)
21.2(42.5)
-
19(38)
17.2(34.5)
-
19.9(39.9)
AA
TSS
10.5(21)
-
28(56)
19.5(39)
19.5(39)
23.3(46.6)
-
-
11.6(23.2)
-
19.1(38.1)
AA
BODS
1.4(2.8)
1.3(1.6)
1.3(1.7)
4.3(8.7)
2.1(4.3)
4.5(2.2)
2.1(4.2)
2.3(4.7)
4.3(8.7)
3.1(6.1)
2.8(5.7)
MM
BODS
2.3(4.6)
1.3(2.7)
2.2(2.4)
5.2(11.5)
3.1(6.1)
3.7(7.4)
3.1(6.2)
3.3(6.6)
9.7(19.5)
5.7(11.4)
4.9(9.9)
MM
BODS*
50
25
32
69
55
43
27
75
-
-
-
AA
TSS
4.7(9.4)
2.2(4.5)
1.05(2.1)
7.1(14.2)
5.6(11.2)
2.5(5.0)
3.6(7.2)
2.9(5.9)
4.7(9.4)
1.0(2.0)
3.7(7.4)
MM
TSS
6.1(12.1)
3.8( 7.6)
1.4( 2.8)
8.8(17.7)
7.1(14.2)
3.9( 7.9)
4.6( 9.3)
3.5( 7.0)
8.2(16.5)
1.6( 3.3)
4.8( 9.6)
MM
. TSS*
119
69
37
101
124
46
34
69
-
-
-
-------
is at a premium. Also, its capacity to handle high concentrations and
shock loads of solids is somewhat limited.
The most widely used method for sedimentation of pulp and paper wastes
is the mechanically cleaned quiescent sedimentation basin (12). 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, clarifier diameters range from 9.1U 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 survey of 12 mills in the five subcategories indicates that
the majority of the plants have primary clarifiers with overflow rates
ranging from approximately 8148-28,518 liters per square meter per day
(200-7CO gallons per square foot per day) .
A properly designed and installed mechanical clarifier 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 BOD5 reduction. Tabulated data for a number of mills showed a BOD5
reduction effected by settling is less than 20 percent for linerboard
mills.
BOI)g Reduction
BOD5 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
of internal chemical losses and recycling have removed most of the
factors which interfere with biological activity.
While BOD5 reduction by biological methods represents common practice
today, it should be understood that other methods discussed under "Color
Removal" may, in the future, avoid the need for biological treatment to
reduce BODS.
107
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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. BOD5_
reductions of 85-95* are presently being achieved. The aerated
stabilization basin is the most widely used method in kraft mill
effluent treatment (42). Storage oxidation ponds are used by many mills
in conjunction with aerated stabilization basins. The activated sludge
process is not used by unbleached kraft mills, and a trickling
(roughing) filter is presently being employed by two kraft mills for
pretreatment (42). A process flow diagram showing alternate biological
effluent treatment systems is shown in Figure 19.
Since the storage 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 (12). Ninety percent BOD5
removal efficiency for an 82-day detention time stabilization basin
treating unbleached kraft waste is reported (42). Design loading rates
of 56 kilograms BOD5 per hectare per day (50 pounds BOD5 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 BOD5, per hectare per day (53 pounds BOD5_ per
acre per day) or less showed BOD5 removals ranging from 80-93 percent,
while basins averaging 112-336 kilograms BOD5 per hectare per day (100-
300 pounds BOD5, per acre per day) had removals in the 23-55 percent
range. For shallow basins an oxygenation rate of 67.3 kilograms BOD5.
per hectare per day (60 pounds BOD5 per acre per day) was reported to be
used for design purposes.
By installing aeration equipment in a natural basin, its ability to
assimilate BOD5 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
natural 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,
significant use of this waste treatment process began in the early to
midsixties.
Due to its inherent acceleration of the biological process, the aerated
stabilization basin requires much less land than the natural stabiliza-
tion basin. Because of the long reaction period, it requires 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 compared with 4.8 hectares per million liters (40
acres per MGD) for natural basins for equivalent treatment levels (42).
Detention times in the aerated stabilization basin normally range from
five to 15 days, averaging about 10 days.
108
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FIGURE 19
o
10
SPILLAGE &
WASH-OUTS
LOW SUSP. SOLIDS
. EFFLUENTS
HIGH SUSP. SOLIDS
EFFLUENTS
WOOD
WASHINGS
INORGANIC
WASTES
CLEAN
COOLING WATER
IN-STREAM
DIFFUSER
STRONG
WASTE
HOLDING BASIN
!
DIVERSION
CHAMBER
BAR
SCREENS
AS
BAS
H
IN
WOOD YARD
RUN OFF
DISCHARGE
REG. BASIN
FLOW METER
•»
METERING
PUMP
COLLECTION
WELL
1
DECANTATION
EFFLUENTS
f
F
M-
PROCESS FLOW DIAGRAM
MILL EFFLUENT TREATMENT
L
f
ROM SLUDGE
HANDLING
r*i rtnTC"Ti~nc
CLARIFIERS
1
ALTERNATE
SETTLING
BASINS
I
STORAGE
OXIDATION
^^•w
ALTERNATE
-
SETTLING
BASINS
AERATED
OXIDATION
ALTERNATE
SECONDARY
CLARIFIER
I
I
AERATION
TANKS
1
I
1
1
if
*
TO SLUDGE
CONDITIONING
AND DISPOSAL
1
1
1
1
1
1
J
WASTE
L _ 1
RETURN ACTIVATED SLUDGE
-------
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 (one pound)
of BOD5 removed (12). The sludge is removed as formed by endogenous
respiration, sludge loss in the effluent, and sedimentation within the
aeration basin. However, discharge of untreated waste to an aerated
stabilization 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.
After dredging the sludge, the process returned 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.5 to nitro-
gen are 50:1 with four days aeration, and 100:1 with 10-15 days aeration
(43) .
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 (D.O.) level of 0.5 mg/1 remaining in the
lagoon liquid is required to sustain aerobic conditions (44) .
Generally, it was reported that 1.1 to 1.3 kilograms of oxygen per
kilogram BOD5. (1.1 to 1.3 pounds oxygen per pound BODS) are required to
maintain adequate D.O. for waste oxidation and endogenous respiration of
the biological 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 is settled in a secondary clarifier and returned to the
aeration tank, building up a large concentration of active biological
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 throug out 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,
no
-------
and cyntomnemotodes. Because the process involves intimate contact of
organic waste with biological organisms, followed by sedimentation, a
high degree of BOD5 and solids removals is obtained.
The contact stabilization process is a variation of activated sludge in
that 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 BODS per cubic meter (150 pounds of BODS per
1000 cubic feet) of aeration tank volume per day (12). Of the mills
studied in all subcategories 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 BODS 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 BODS per 1000 cubic feet) have been reported (43). In all
cases nitrogen and phosphorus were added.
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 reported (42).
Due to the fact that the volume of bio-mass in the activated sludge
process is greatly reduced because of hydraulic detention time, the
endogenous respiration of the concentrated sludge is considerably
lessened. Thus, there are additional quantities of excess sludge, 3/4
kilogram of excess sludge per kilogram of BOD5 (3/4 pound of excess
sludge per pound of BODS), which must be disposed.
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 were reported in the range of one kilogram of oxygen per
kilogram of BOD5 (one pound of oxygen per pound of BODS) 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 BODJ5 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.
in
-------
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 process with its
much lower land requirement. One such use is in paperboard from waste
paper 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 BODS
removal at high loading levels (43). A kraft mill employing trickling
filters with artificial plastic media achieved 50 percent reduction of
BOD5 with 50 percent recycle at a loading rate of 80.16 kilograms of
BOD5 per cubic meter of media per day (500 pounds of BODS per 100 cubic
feet of media per day) (43). Another mill indicated that research had
shown in order to achieve SOX reduction in BODS, the loading rate had to
be 16 kilograms of BOD5. per cubic meter of media per day (100 pounds of
BOD5 per 1000 cubic feet of media per day) (45).
Two-Stage Biological Treatment
Two-stage biological treatment is employed as an alternative for BODS
removal obtained with a single stage. This concept consists of two
biological treatments systems, usually arranged in series. In the
literature (46). a two-stage system is described which employs the
activated sludge process in both stages in the treatment of municipal
water. The authors note that sludge may be returned or wasted within
each stage, or that excess sludge from one stage may be recycled to the
other. A principal advantage of this particular arrangement is that the
sludge flows may be utilized to maximize BOD5_ removal.
Other combinations of biological treatment may be employed in a two-
stage arrangment. For example, a trickling filter may precede an
aerated stabilization basin or an activated sludge system. This
arrangment may be employed where the second stage is required because of
insufficient performance of the trickling filter alone. It may also be
used in cases where cooling of the waste is required before further
biological treatment may proceed. In the latter case, the trickling
filter serves as a partial cooling tower, and also accomplishes some
BOD5_ reduction. *
Two-stage aerated stabilization basins, operated in series, may have
particular appeal for this industry. This arrangement usually requires
less land than a single unit, and can be expected to provide better
treatment on an equal-volume basis. For the first stage, a detention
time up to two days or more is usually recommended, and up to 10 days or
more for the second stage. If sufficient land is available at
reasonable cost, this system is usually a less expensive approach than a
two-stage system involving activated sludge. It has the further
advantage of providing more detention time which is helpful in treating
surges of flow or pollutant load. In colder climates, however, arrange-
ments using aerated stabilization basins are more susceptible than
112
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activated sludge to decreased wintertime performance. This, in turn,
relates to the greater heat loss of the aerated stabilization basin due
to its greater detention time as compared to activated sludge. Under
conditions of proper design and operation, including nutrient addition
and surge basins located prior to biological treatment, BODS removals of
well over 90 percent can ultimately be expected to be achieved with this
system.
A two-stage biological system currently employed by some Southern un-
bleached kraft mills utilizes an aerated stabilization basin followed by
storage oxidation ponds. Typically, detention time of the former is
eight to 14 days and for the latter is eight to 60 days. In these
installations, overall BOD5 removals (compared to raw waste) of 85-95
percent are being achieved, with 55-70 percent removal after the first
stage. These data do not, however, reflect usage of nutrients. It is
probable that the addition of surge basins, coupled with nutrient
addition, proper aeration and mixing capacity, will ultimately permit
BOD5 reductions of well over 90 percent in these systems. For mills
with adequate land and other favorable factors, this system may be the
most economical approach. The low removal efficiencies in the aerated
stabilization basins are considered to be normal practice as
historically, the storage oxidation pond was first utilized as the only
biological treatment for reduction of pollutants at these mills. As
environmental pressures mounted, many mills then installed ASBs as a
treatment step prior to the storage oxidation ponds. The ASB's were
thus designed as part of a two-stage biological system with reliance
upon the storage oxidation pond for further reduction of pollutants.
The aerated basins were designed such that the storage oxidation ponds
are utilized to further remove BOD5 to the normally accepted secondary
treatment removal efficiencies of 85-95% for the total two stage system.
Other combinations of two-stage biological treatment are,'of course,
possible. These would include use of activated sludge followed by an
aerated stabilization basin, storage oxidation, or trickling filters.
Such combinations, with rare exceptions, would not usually be the more
economical or practicable solution, however.
Temperature Effects
All biological treatment systems are sensitive to temperature. Optimum
temperature for these systems is generally in the 16° to 38°C (60° to
100°F) range. BODjj removal efficiency is usually lessened as
temperature of the waste water drops significantly below or rises
significantly above this range.
Temperatures over 38°C may be encountered in warm climates where heat is
also added to the waste stream during processing. Cooling towers or
trickling filters have been employed to reduce these higher temperatures
prior to biological treatment. In colder climates, waste water
113
-------
temperature is likely to drop below 16°C in the winter, particularly
where detention time of the biological unit exceeds 12 to 24 hours.
With greater detention times, heat loss to atmosphere from the treatment
unit generally becomes significant. Thus activated sludge units, which
are usually designed for two to 10 hours detention, are less susceptible
to reduction of BOD£ removal efficiency in cold climates than are
aerated stabilization basins or storage oxidation basins.
The lessened efficiency of BOD5 removal can be mitigated in colder
climates by improved design of aeration and mixing factors. Two-stage
aerated stabilization basins are likely to perform better in cold
temperatures than a single stage of greater total detention time.
Sludge Dewatering and Disposal
Due to their high organic content, the dewatering and disposal of
sludges resulting from the treatment of kraft linerboard 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 rainfall was decanted. When a basin
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 (47) and are described briefly below.
Depending on the performance of dewatering 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.
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. For comparison, filtration rate
ranges observed for each subcategory are as shown in Table 28.
114
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TABLE 28
Vacuum Filtration Rates of Sludges
Product Dry kg/m2/hr Dry .J/ft2/hr
Unbleached Kraft 39 to 93 8 to 19
Paperboard from 10 to 29 2 to 6
Waste Paper
NSSC 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 area per day). After initial problems, filter
availability exceeded 94 percent and cleaning problems were minor (48).
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
115
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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 paperboard mill sludge
set forth parameters of good practice and area requirements (49). 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 linerboard mills, can be dewatered to
a solids content approaching 40 percent by pressing (50). "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 linerboard sludge, thus eliminating the first dewatering step.
Generally, pressing is followed by incineration in air-entrained incine-
rators which can burn the pressed sludge without supplemental fuel since
little further drying is required (51) . Semi-chemical corrugating board
operations and paperboard from waste paper 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 operations in existing fossil fuel-fired power
boilers.
Sludge is also incinerated at some linerboard mills in boilers burning
bark or hog fuel. In this case, the pressed sludge is mixed with the
bark or fuel before introduction into the furnace (47).
Both types of operation are described in the literature (51) (52) (53),
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 ($11.50 per short ton) of dry solids.
Land disposal, via dumping or lagooning, has been a common means of
disposing of waste sludges and other solid wastes from many pulp and
paper mills. Odors formed upon decomposition of these materials, the
potential for pollution of nearby surface waters, and the elimination of
affected lands from potential future usages, have made such practices
generally undesirable. If disposed of using proper sanitary landfill
techniques however, most solids from the pulp and paper industry should
create no environmental problems. In the rare cases where sludges may
contain leachable quantities of taste or odor imparting, toxic, or
116
-------
otherwise undesirable substances, simple sanitary landfilling may not be
sufficient to protect groundwater quality.
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. Several researchers (51) 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 in 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.
Several mills are presently experimenting with using the sludge as a
soil supplement in reclaiming land for growing pulp wood. Application
of primary sludge to the land at loads (dry solids) of 224-148
kkg/hectare (100-200 tons per acre) are being practiced. Cbttonwoods
are being grown with planned harvest and reapplication of sludge in
three to five years following planting.
Interest in production of bacterial protein from cellulosic 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 f usca, a strongly cellulolytic thermophylic organism on low
lignin pulp mill fines (54). 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.
117
-------
oo
SLUDGE FROM
TREATMENT PLANT
1
WASTE SLUDGE
METER
1
GRAVITY
THICKENER
1
1
1
1
1
I
1
1
I
m
MMM*BM
—m
^^^^•B
•I
FILTERS
ALTERNATE
CENTRIFUGES
ALTERNATE
DRYING BEDS
_1
1
1
*
1
I
1
__rfrt\_«-M
1
1
1
*
— VI
—
— *
FILTRATES TO
TREATMENT PLANT
STACK
(OFF-GASES)
•
1
•
1
INCINERATOR
" * AbHtS
ALTERNATE
, LAND
DISPOSAL AREA
t
1
1
1
1
J
SLUDGE DEWATERING AND DISPOSAL
FIGURE 20
-------
Color Removal
For more than twenty years, the pulp and paper industry has been active-
ly engaged in research for the reduction of color, primarily in kraft
mill effluents. The bulk of the research 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, alum preci-
pitation, resin absorption, ion flotation, ultrafiltration, and amine
treatment. Alum precipitation was found to be economical in one
instance where alum mud from the nearby manufacture of alum is the
primary chemical source. The alum precipitation technique has recently
been applied in full scale but a number of operating problems have
occurred.
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 yet been completed.
Sources of color
In the various chemical pulping processes, lignin and lignin derivatives
are solubilized 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, with the
exception of the stock decker discharge, where the cooking chemicals are
recovered and the organic materials are burned in the recovery furnace.
The washing and recovery operations are efficient; however, losses of
cooking liquor and the discharge of evaporator condensate and decker
filtrate result in a reddish brown effluent. Average values of color
discharged from unbleached kraft papermaking operations are shown in
Tables 29 and 30 (42) .
119
-------
TABLE 29
SOURCES OF COLOR
Effluent kg/kkg jib/ton)^*
Kraft Pulping 25-150 (50-300)
Kraft Papermaking 1.5*4 (3-8)
*Based on APHA color units"
TABLE 30
UNIT PROCESS FLOW AND COLOR DISTRIBUTION
IN INDIVIDUAL KRAFT PULPING EFFLUENTS
kiloliters/kkg
Unit Process .(1.000. gal/ton) Color Units
Paper Mill 47.6 (11.4) 10
Pulp Mill 3.8 (0.9) 520
Evaporators 0.4 (0.1) 3760
Recovery 0.8 (0.2) 20
Caustic House 3.3 (0.8) 20
120
-------
Lime Treatment
The development of the lime color reduction process has been traced by
several authors (12) (42) (55) (56). Based on the results of early work,
research was directed towards development of the lime precipitation
process with the overriding problem of the difficulty of dewatering the
lime-organic sludge. Specific studies were conducted for resolving the
sludge problem with limited success (57) (58). Continuing efforts to
improve the dewatering of the lime sludge led to consideration of using
large dosages of lime for color reduction. In this process (massive
lime process), the mill's total process lime is slaked and reacted with
a highly colored effluent stream. The lime sludge is then settled,
dewatered, and used for causticizing green liquor. During the
causticizing process, the color bodies are dissolved in the white liquor
and eventually burned in the recovery furnace. Demonstration of the
massive lime treatment system for unbleached kraft waste waters has been
conducted on a 2000 liters/min (530 gpm) basis (59). Two phases of
operation were conducted on unbleached kraft decker effluent. Over 91
percent of the average 1,640 APHA CU were removed during operations
which had very little white water reuse in the decker pulp washing
operations. When nearly all of the water used in the decker system was
white water, the removal efficiency dropped to 74 percent of the initial
900 APHA CU. A flow diagram of the process is shown in Figure 21.
The massive lime process, as developed, relies on high concentrations of
lime (on the order of 20,000 mg/1) (60). Because of this, only a
relatively small effluent stream could be treated with the quantity of
lime used for causticizing 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 processes 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
(61) (62) .
The results of one of the mill's operations show that color is removed
from unbleached kraft waste waters under conditions of widely varying
raw waste color loads. A relatively constant effluent color of 125-150
APHA CU was obtained independent of influent color levels. The mill
influent color levels were generally in the range of 1000-1400 APHA CU.
With a lime dosage of 1000 mg/1, removal efficiencies were consistently
well above 80 percent. Results of the color removal operations are
shown in Table 31 and a flow diagram is shown in Figure 22.
121
-------
ro
ro
LIME
MAKE-UP
LIME
SLAKER
BLEACHERY EFFLUENT
UNDERFLOW
VACUUM
FILTER
KILN
I
CLARIFIES
FILTRATE
•GREEN LIQUOR
u
WHITE LIQUOR
CLARIFIER
CAUSTICIZING
C02
LIME RECLAIMER
DECOLORIZED
EFFLUENT
LIME MUD
TO KILN
MUD
WXSHER
MASSIVE LIME PROCESS FOR COLOR REMOVAL (9)
FIGURE 21
-------
Averages *
TABLE 31
Color Reduction by Minimum Lime Treatment
Month
November 1968
December 1968
January 1969
February 1969
March 1969
April 1969
May 1969
June 1969
July 1969
August 1969
September 1969
October 1969
November 1969
December 1969
Data Points
7
1
3
8
12
8
10
11
13
12
7
12
9
3
Inf 1 uent
1060
1500
2100
2470
1230
1300
690
1230
1430
1150
1450
1750
1690
1800
APHA Color Units
Effluent %
110
150
160
170
105
110
83
95
110
no
140
135
150
170
Reducti on
88
90
91
91
91
84
84
90
91
90
90
92
91
90
1360
120
89.5
Weighted averages by number of data points per month.
123
-------
LIME STORAGE TANK
VARIABLE SPEED
SCREW CONVEYOR
(10 MOD MAX)
S MOD
14000* BOD/DAY
BIOCHEMICAL TREATMENT LAKE
650 ACRES - 900 MG
(180 DAYS RETENTION)
MOTORIZED SLUICE GATE
EFFLUENT LIFT PUMPS
3500 GPH 50' TDH
HOLDING LAGOON 48 MG
Figure 22
Minimum Lime Process for Color Removal (55)
-------
The other full scale installation of the minimum lime process is at an
unbleached kraft-NSSC (cross recovery) mill, and the system has been
operating for more than two years. As shown in Figure 23, effluent from
the mill following grit and trash removal is pumped to a clarifier where
approximatey 1000 mg/1 of lime is added to the clarifier influent.
About 60* of the lime, most of the color bodies, and virtually all of
the settleable solids settle to the clarifier bottom. The sludge is
removed, thickened by centrifuge, and burned in the mills' lime kiln.
The overflow from the clarifier is treated with carbon dioxide using
lime kiln stack gas which converts the soluble lime to insoluble lime.
The insoluble lime is removed in a second clarifier and also burned in
the lime kiln (63) .
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. Specifically, research into color removal systems
for bleached kraft mills which may through further work be applicable to
unbleached mills are such systems as resin adsorption, ion flotation,
ultrafiltration, and high molecular weight amine purification.
Coagulation Techniques
The effects of alum and ferric chloride for the removal of color from
kraft mill effluents was investigated in the laboratory (6U) . 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.
Laboratory investigation was conducted of alum and six organic
polyelectrolytes for the removal of color from kraft mill waste water
(65). Little difference was reported in the performance of the six
polyelectrolytes was reported. Alum produced good results, but resulted
in approximately three times the volume of sludge. Color removals
averaged 95 percent.
125
-------
Figure 23
Color Reduction by Minimim Lime With Lime Recovery
LIME KILN
LIME
STORAGE
ro
ot
MILL
EFFLUENT
SLAKER
" *"!
GRIT
CHAMBER
! COLOR C02
'; CLARIFIER i
j ' •'••>:
^^^Z^^' CARBONATION
i BASIN
CARBONATION
CLARIFIEP
.v---d ' I •>••
'^^<^^
'• ^:^
j7
OUTLET
BASIN
COLOR SUTDGE
COLOR SLUDGE CENTRIFUGE STORAGE TANK !
CAUSTIC MUD
-. STORAGE TAtJK
I'*'
LIME MUD
VACUUM
FILTER
TO KILN
-------
Activated Carbon
Researchers (42) 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 24. 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.
The lime-carbon system is referred to by the authors as "micro" lime
treatment as compared to the "minimum" lime treatment used by others,
(60) (61) (62) (63). 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 an extent allowing reuse in the mill. In this
respect they were not necessarily looking for a combination of systems
capable of producing an effluent suitable for discharge.
Other researchers (66) 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.
Similiar investigations were also (67) made on a pilot scale. They
investigated the effects of massive lime treatment, biological
oxidation, and absorption in granular carbon columns. In addition one
reacher investigated the effect of activated carbon as a polishing step
following 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 (68).
127
-------
1 ii ' 1
°* ' 1! '
j 4- i
^
•• | lr
'(!
tir
T_C°Z
I! ;..
» i
-> SLUDGE
LIME TREATER CARBONATOR
pH
ADJUST-
MENT
ro
00
FILTER ACTIVATED CARBON COLUMNS
STORAGE
TANK
No. 2 MILL
EFFLUENT
CLARIFICATION
tQUIUBRATION OR
BIO-OXIDATION BASIN
r- ACTIVATED CARBON
LL
?s
CONTACTORS
FILTER
STORAGE
TANK
FIGURE 24
ctivod
Car":; or; lilot Plant
-------
Comparison of System Efficiencies
It was reported 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
(42). This is shown in Table 32. It is estimated that an additional
three columns would be required to produce the goal of 100 color units.
The primary clarification-carbon system tested used four columns. Color
was reduced to 185-202 units. This is shown in Table 33. As with the
biological-carbon system, it was estimated that an additional three
columns would be required to reach 100 color units.
TABLE 32
CARBON ADSORPTION SEQUENCE AT 57 1/min. (15 qpm; 2.3 qpm/ft2)
Range
Feed to bio-oxidation, APHA CU 430-2500
Feed to carbon, APHA CU 460-1100
Product from carbon, APHA CU 42-400
Removal by bio-oxidation plus filter,*
Removal by carbon, % of feed to carbon
Total removal % feed to bio-oxidation
Rate of removal by carbon, CU/g hr 0.51-1.00
Average
11CO
740
212
33
71
81
0.77
Note: Color measured at pH 7.6 after 0.8 micron Millipore filtration.
TABLE 33
COLOR REMOVAL BY PRIMARY CLARIFICATION - CARBON ADSORPTION
Flow rate, liters/min(gpm)
Flow rate, Iiters/min/ft2(gpm/ft2)
Feed to Carbon, APHA CU
Product fronj Carbon, APHA, CU
Removal by Carbon
Rate of Removal by Carbon CU/g hr
Trial_l
37.8(10)
5.4(1.42)
925
185
80
0.69
Trial 2
18.9(5)
2.7(0.71)
11160
202
83
0.46
Note: Color measured at pH 7.6 after 0.8 micron Millipore filtration.
129
-------
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 25. Color removal in the carbon columns (2
columns in series) was also found to be dependent on Ca concentration.
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 percent,
to give an overall reduction of 90 percent. This is shown in Table 3U.
Water of this quality was considered suitable for reuse.
Operation of the FACET system following lime treatment produced similar
results to the two carbon columns after filtration. This is shown in
Table 35.
A total color removal in the four stage (lime - carbonation - oxidation
- carbon) system of 99.5 percent was reported (61). In the three -
stage system (no oxidation) the total removal was again 99.5 percent.
This is shown in Table 36.
As shown in Tables 37 and 38, 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.
Operation Considerations
It was concluded that the use of a sand filter ahead of the carbon
system did not provide enough benefit to warrant consideration in a
full-scale installation (69). The investigators also noted concentrated
bioactivity 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 the lime-carbon system, lime
dosages were recommended to control the dissolved calcium concentration
at about 80 mg/1. 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 <*00 mg/1 followed by carbonation and
carbon treatment did not improve color reductions.
130
-------
CO
Q.
fief
O
_i
O
O
:E
Q.
U-
O
100
90
80
70
60
50
40
30
g 20
S 10
Xp
^ 0
'O
O
I I 1 I I 1 I I I I
40 120 200 280 360
0 80 160 240 320 400
SOLUBLE CALCIUM FROM LIME TREATER,' MG/L
FIGURE 25 COLOR REMOVAL IN LIME TREATMENT AS A
FUNCTION OF SOLUBLE Ca IN WATER (74)
-------
Table 34
COLOR REMOVAL BY LIME TREATMENT - CARBON ADSORPTION
SEQUENCE AT SOLUBLE CALCIUM RANGE OF 69 - 83 mg/1 (29)
lime dosage, CaO, mg/1 523
pH of feed to carbon adsorption 11.3
flow rate to carbon adsorption, gpm 10
No. of carbon columns 2
Color, TOG,
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
132
-------
Table 35
REMOVAL OF COLOR AND TOG BY
FACET CARBON ADSORPTION FOLLOWING LIME TREATMENT FOR 12-DAY PERIOD
10/20 THROUGH 11/6 (29)
Conditions:
Water feed rate 10 gpm
Carbon feed rate 2.7 Ib/hr = 4,5 lb/1000 gal
Carbon in system 605 Ib
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
133
-------
Table 36
WASTE WATER RENOVATION—SUMMARY OF RESULTS (25)
5-DAY BOD
COLOR
CO
Treatment
Step
Raw
Lime
Biol.
Carbon
Total
Max.
Min.
Avg.
Max.
Min.
Avg.
Max.
Min.
Avg.
Max.
Min.
Avg.
Four-s tage
mg/ liter
1430
225
723
740
170
395
135
21
48
80
0
23
23
process Three-stage process Four-stage process
% Removal nig/liter
265
206
221
144
69
45.5 102
88
84
15
53 32
97 32
% Removal Units % Removal
12,000
1,000
5,200
1,000
90
54 358 93
1,000
200
365 0
15
10
68.5 13 96.5
85.5 13 99.5
Three-stage process
Units
5250
240
3558
450
10
185
55
0
23
23
% Removal
95
87.5
99.5
Tests Conducted on Bleached and Unbleached Kraft Effluents.
-------
Table 37
RENOVATED WATER ANALYSIS (26)
UNBLEACHED KRAFT LINERBOARD TOTAL MILL EFFLUENT
PILOT PLANT RUN NO. 1 50 GALLON BATCH OPERATION
u>
en
Constituent
Turbidity, ppm
Color, units
PH.
Hardness, ppm CaCOjj
Dissolved solids, ppm
Chloride, ppm
COD, ppm
BOD, ppm
Na, ppra
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
818
1400
Obtained by Treatment
Bio^"'Carbon^
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 Ibs, reburned lime slaked and added to raw effluent (equivalent to
20,000 ppm Ca(OH)2).
(b) Extended aeration for 10 days. One gallon fertile lake water added as seed
material. NH^OH, HN03 and H3P04 added as nutrient. ^804 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 38
RENOVATED WATER ANALYSIS (26)
CO
-EACHED KRAFT LINERBOARD TOTAL MILL EFFLUENT
: PLANT RUN NO. 2 50 GALLON BATCH OPERATION
Obtained by Treatment
isired Range
5-25
0-80
6.5-7.7
5-200
50-500
10-150
0-12
0-5
-
Effluent
_
3000
7.5
-
4190
160
«.
1430
320
Lime(a)
_
100
12.1
964
2610
200
—
740
230
Bio ,
_
200
8.2
1000
3070
130
_
(135)
230
(c
Carbon^ '
_
15
8.5
866
2800
130
_
(80) (*
230
Constituent
Turbidity, ppm
Color, units
pH
Hardness, ppm
Dissolved Solids, ppm
Chloride, ppm
COD, ppm
BOD, ppm
Na, ppm
Notes: (a) 2.87 Ibs. returned lime slaked and added to raw effluent (equivalent to 7500 ppm
Ca (OH)2).
(b) Extended aeration for 8 days. One gallon fertile lake water added as seed
material. HNO^, H^PO^ added as nutrient. HjSO^ added to neutralize.
(c) Carbon columns containing 12x40 mesh activated carbon furnished by Pittsburgh
Carbon. Contact time in carbon bed was 1.6 minutes.
(d) Estimate, incubator problems.
-------
The authors 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 has been directed towards reuse of the
treated effluent. As 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. They are confident the
kraft process contains unit processes by which any buildup in
contaminants due to recycling can be purged from the system (70).
Others (71) found that elimination of biological oxidation in the lime -
carbonation •*• biological - carbon sequence did not affect color
reduction, and BOD5 reduction remained about 85 percent when treating
effluents with a moderate raw BOD5. They point towards further research
toward improved BOD5 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.
Resin Adsorption
Most research effort on color removal by resin adsorption has been done
on bleached kraft effluents. A full scale resin adsorption color
removal systems is operating in Sweden at a bleached kraft mill and at
least one additional system is being installed at a mill in Japan (72) .
In addition, pilot scale studies have been conducted at mills in western
Canada (73) at an eastern United States mill (74).
The resin adsorption systems do show potential for removal of color from
unbleached kraft mills as research is continuing on the application of
resin adsorption systems to unbleached kraft mills. However, the resin
adsorption systems will not be discussed in detail in this report since
most work has been conducted on bleached kraft mills.
Ion Flotation
The ion flotation technique for removal of color from kraft mill
effluents has been operated on a bench scale in western Canada (75).
The system basically involves the addition of a surfactant ion of the
opposite charge to the ionic species (color bodies) which is to be
removed. The surfactant ion combines with the color bodies to form a
precipitate which is buoyed to the surface by passage of air through the
solution (i.e., dissolved air flotation) and removal of the resulting
froth layers removes the color.
The bench scale studies have shown that a very substantial removal of
color could be obtained. The optimum color removal conditions were
found to exist in the pH range of 3.0 to 5.0 at a surfactant dosage of
500 mg/1. Color removal efficiencies were reported to be over 95% under
these conditions.
137
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The ion flotation system shows potential for color removal. However,
additional research is necessary into (1) application to unbleached
kraft effluents, and (2) techniques to regenerate the surfactant.
Ultrafiltation
Ultrafiltration techniques for color removal have been investigated on a
pilot scale on bleached kraft mill caustic extract effluent and decker
effluents (76). Color removals of 90-97% were obtained but plugging of
the membrane cartidges was troublesome.
Figure 26 shows the basic ultrafiltration flow schematic.
Ultrafiltration is a membrane process and as such is related to reverse
osmosis. The ultrafiltration process uses a semi-permeable membrane
with an applied hydrostatic pressure as the driving force. The waste
water is passed through the membrane, and solutes whose sizes are larger
than the membrane pore size are retained and concentrated at the surface
of the membrane. The concentrated solutes are removed in solution.
Before full scale application of ultrafiltration, additional research
needs to be conducted into the problems of membrane plugging and to
determine the long term membrane cartidge life.
High Molecular Weight Amine Treatment
The use of high molecular weight amines for the removal of color from
pulp mill effluents was first investigated in France and then more
recently in Canada. Amines (in a water-immiscible solvent) have been
shown to react with the color bodies in kraft mill effluents and to form
a precipitate which can be separated and redissolved in a strong
alkaline solution such as white liquor for regeneration of the amine.
Results of bench scale investigations have shown that the amine
decolorization technique is capable of removing 90-99% of color from
kraft mill effluents. The basic amine treatment process is shown in
Figure 27.
138
-------
PERMEATE
CO
ID
° «-
0
0 •
o
-°
-
. o . QO
MEMBRANE
. p.p.
MEMBRANE
• DISSOLVED SALTS
O COLOR BODIES
SIMPLIFIED ULTRAFILTRATION FLOW SCHEMATIC
Figure 26
-------
MILL EFFLUENT
SO
CAUSTIC
SOLUTION
AMINE
-COLOUR BODIES
PRECIPITATE
TREATED EFFLUENT
AMINE
SOLUTION
MAKE-UP
REGENERATED
AMINE SOLUTION
THIRD-PHASE
EMULSION
SPENT
CAUSTIC
SOLUTION
SIMPLIFIED AMINE TREATMENT PROCESS FLOW DIAGRAM
Figure 27
-------
Treatment Systems for Additional Reductions of Suspended Solids and
Refractory Organics
Treatment technologies for additional reductions (over those previously
discussed) of suspended solids and refractory organics are discussed
below.
Suspended Solids
Flocculation, Coagulation, and Sedimentation for Suspended Solids Removal
To avoid rapid plugging of final filters, an additional step to remove
suspended solids contained in biological treatment effluents may be
required.
Traditional treatment systems have utilized rapid-mix and flocculation
basins ahead of sedimentation tanks for chemical clarification. The
rapid mix is designed to provide a thorough and complete dispersal of
chemical throughout the waste water being treated to insure uniform ex-
posure to pollutants which are to be removed. In-line blenders can be
used as well as the traditional high-powered mixers which may require as
much as 0.35 kilowatts/MLD (1 horsepower/MGD). In essence, the rapid
mix performs two functions, the one previously noted (mixing) and a
rapid coagulation. These functions are enhanced by increased
turbulence.
Flocculation promotes the contact, coalescence and size increase of
coagulated particles. Flocculation devices vary in form, but are gener-
ally divided into two categories. These are mechanically mixed and
baffled flocculators. Baffled basins have the advantage of low
operating and maintenance costs, but they are not normally used because
of their space requirement, inability to be easily modified for changing
conditions and high head losses. Most installations utilize horizontal
or vertical shaft mechanical flocculators which are easily adjusted to
changing requirements.
Solids-contact clarifiers have become popular for advanced waste water
treatment in recent years because of their inherent size reduction when
compared to separate mixing, flocculation and sedimentation basins in
series. Their use in water clarification and softening was carried over
to waste treatment when chemical treatment of waste waters was
initiated. Theoretically, the advantage of reduced size accrues to
their ability to maintain a high concentration of previously-formed
chemical solids for enhanced orthokinetic flocculation or precipitation
and their physical design, whereby three unit processes are combined in
one unit. In practice, this amounts to savings in equipment size and
capital costs.
141
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Problems have occurred with the sludge-blanket clarifiers for reasons
which include possible anaerobic conditions in the slurry, lack of
individual process control for the mixing, flocculation and
sedimentaiton steps; and uncontrolled blanket upsets under varying
hydraulic and organic loading conditions. The major allegation is the
instability of the blanket, which has presented operational problems in
the chemical treatment of waste waters. Possibly the most effective
method of control to date, other than close manual control, has been to
mimimize the blanket height to allow for upsets. The advantages of
higher flow rates and solids-contacting are maintained, but the added
advantage of the blanket is minimized. Another possibility which has
not been fully evaluated is the use of sludge-blanket sensors for
automatic control of solids wasting.
Solids-contact clarifiers have been used for the treatment of secondary
and primary effluents, as well as for the treatment of raw, degritted
waste water. Lime as the treatment chemical has been used with overflow
rates from 20,400 to 40,700 liters per day per square meter (1200 to
1700 gpd/sq ft) in solids-contact units, while iron compounds and alum
have been used at lower values, usually between 48,900 to 69,300 liters
per day per square meter (500 and 1000 gpd/sq ft) . All of these rates
come from pilot studies of less than 3.78 MLD (1 MGD) capacity, and may
be subject to change at a larger scale due to differences in hydraulics.
Polymer treatment can also influence the choice of overflow rates for
design if their cost can be economically justified when compared to the
cost of lower overflow rates. Detention times in these solids-contact
basins have ranged from just over one to almost five hours. Sludge
removal rate is dependent on the solids concentration of the underflow,
which is a function of the unit design as well as the chemical employed.
These pilot plants have reported lime sludge drawoffs from 0.5 to 1.5
percent of the waste water flow at concentrations of from 3 to 17
percent solids. Alum and iron sludges have not been monitored
extensively, but drawoffs have been reported to be 1 to 6 percent of the
flow with 0.2 to 1.5 percent solids.
Much of the design information necessary for solids-contact clarifiers
has been obtained from water treatment experience. This is not sur-
prising in that the principles of treatment are identical. The charac-
teristics of the solids that are formed and separated are the source of
differences. The organic matter contained in the chemically created
sludges causes the sludge to become lighter and also more susceptible to
septicity due to the action of micro-organisms. The former condition
suggests lower hydraulic loadings, while the latter suggests higher
ones, given a set physical design. Since sludge septicity is neither
universal nor uncontrollable, a lower design overflow rate may comprise
much of the necessary adjustment to waste treatment conditions from
those of water treatment. As indicated previously, design overflow
rates from 48,900 to 69,300 liters per day per square meter (1200 to
1700 gpd/sq ft) for lime treatment and from 20,400 to 40,700 liters per
day per square meter (500 to 1000 gpd/sq ft) for alum or iron treatment
have been successful at less than 3.78 MLD (1 MGD) capacity. Cold
142
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weather peak flow conditions will probably constitute the limiting
condition, as water treatment practice has shown that overflow rates are
reduced by as much as 50 percent at near-freezing temperature.
Wastewater will probably not reach such low temperatures in most areas,
but the effects are significant.
Mixed-Media Filtration
Mixed (multi) media filters are similar to conventional single media
deep-bed sand filters, but employ more than one filter media. Typical
arrangements employ garnet, sand, or anthracite.
Conventional sand filters have the finer mesh material on top of the
bed, with courser grades below. Flow is downward. Thus most of the
suspended solids are trapped in the top inch or two of the bed. Certain
types of suspended solids, such as those from biological treatment,
rapidly plug the top of the bed, requiring very frequent backwashes.
Multi-media filters have been designed with the objective of overcoming
this disadvantage of single-media filters. Large size media is employed
on the top layer, over a second layer of finer media. Usually
anthracite coal is used in the top layer, and sand in the lower layer.
Thus larger particles of suspended solids are trapped in the top layer,
and finer particles in the lower layer. The result is to extend the
filter "run" before backwashing is required. An extension of this
principle is to add a third, finer, layer of garnet below the sand
layer. Since some intermixing of layers occurs, there tends to be a
continuously decreasing particle size of media as depth increases. The
different media are selected so that the top bed has the lowest specific
gravity, and successively lower beds have successively higher specific
gravities. With this arrangemnet, the bed layers tend to maintain their
respective physical locations during and after the turbulence created by
backwashing. Typical arrangements for dual media filters are anthracite
(specific gravity 1.6) over sand (specific gravity 2.65). A layer of
garnet (specific gravity 4.2) is imposed below the sand for a three-
media filter.
Studies on municipal wastes have indicated that multi-media filters
outperform single-media sand filters. Better removal of suspended
solids was obtained with longer runs and at higher flow rates per unit
area of filter bed.
Refractory Ororanics
The advanced waste treatment systems studied for the removal of trace
refractory organics include the following: 1) activated carbon, 2)
chlorination, and 3) ozonation. The activated carbon process has
demonstrated its applicability to the treatment of municipal waste water
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-
143
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merited 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-
ganics 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 (78). Many researchers have
studied the use of activated carbon as a tertiary process for the treat-
ment of pulp and paper mill wastes. One of the studies (79) found that
activated carbon was capable of reducing color, COD, BODS, and odor in
kraft mill effluents to very low concentrations.
One of the highest concentrations of BODE> in the whole kraft pulp mill
waste discharge is contained in the evaporator condensate (80) . Most of
the BODS and COD of the condensate waste is exerted by dissolved organic
material. Several researchers (80) found that 75 percent of the BODS,
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 (<*50-1800 sq. m/g) (69) . This large surface area is one
feature of activated carbon which results in its large adsorption
capacity. It can be separated into two general classifications;
powdered and granular. The ultimate adsorption capacities of both
powdered and granular carbons are essentially equal (69); however,
powdered carbon has faster adsorption rates than granular (81) (82).
The number of carbon manufacturers and their particular specifications
is very large. The selection of a specific carbon cannot be made,
however, without first testing the carbon under consideration with the
particular effluent to be treated (83).
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 has been
reported. This is partially due to the fact that adsorption is not the
only mechanism responsible for the removals of organics through carbon
columns. Three functions describe the operation of carbon columns (8U);
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
one study (66) , renovated waste water suitable for reuse can be obtained
144
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without a biological oxidation step, particularly if the renovation
process starts with a moderate BOD5 to 200-300 mg/1. Table 39 presents
the pilot plant results obtained by this study.
Other researchers (81) found that adsorption equilibrium increased 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
effluents (85). Also, carbon columns do a relatively poor job of
removing turbidity and associated organic matter (83). Some highly
polar organic molecules such as carbohydrates will not be removed
through carbon columns (80) (83). However, most of these materials are
biodegradable and would not be present in appreciable quantities in a
well bio-oxidized secondary effluent (83) .
Results of laboratory rate studies (82) 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. The researchers considered five
different contact systems during their laboratory 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, the countercurrent agitated tank system
was considered as 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.
U. 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
145
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Table 39
RESULTS OF GRANULAR ACTIVATED CARBON COLUKN
PILOT PLANT TREATING UNBLEACHED KRAFT MILL WASTE
BOD, mg/1
COD, mg/1
SS, mg/1
Turbidity, J.U.
Color, Units
Odor
PH
T.S. mg/1
Columns*
Preceded by Line
Precipitation and
Biological Oxidation
Influent
48
—
—
—
—
365
—
ww
Effluent
23
—
—
—
—
13
—
'
Removal
52%
—
—
—
—
96%
—
•
Columns*
Preceded by Lime
Precipitation
Influent
102
—
—
—
—
185
—
"rm
Effluent
32
—
—
—
—
23
—
^~
'Removal H Influent
!
69%
—
—
—
—
88%
—
•M
82
320
115
35
28
—
11.9
1285
Effluent
12
209
74
35
0
—
10.5
1205
Removal
852
35%
36%
0%
100%
—
12%
6%
*Colunns loaded at 3.6 - 4.0 gpm/ft2
-------
down with the carbon due to flocculation.
They reported that the processes investigated for separating the
powdered carbon from the treated waste water were not 100 percent
effective and filtration of the waste water 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. Other
research (80) has showed that 70-75 percent of the organic matter from
kraft evaporator condensate could be removed with O.U6 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 results of the
work conflict with those reported by 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 this study may have been contaminated with black
liquor carry over.
One research program (69) ran extensive pilot plant tests for treating
unbleached 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. <•
U. 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
criterion 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 kiloliter (2.5 pounds of carbon per 1000 gallons) treated.
147
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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 liters) treated.
It was found that non-adsorptive mechanisms accounted for a significant
amount of color and TOC removal in the clarification-carbon process. It
was felt that the removals were not due to any biological degradation
which might 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 backwashing process (69). 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 is the subject of a patent application (69) 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. The FACET
system showed distinct advantages over the column adsorption system
(69). Table 40 tabulates the pilot plant results obtained from the
above investigation.
The use of granular activated carbon for the removal of trace refractory
organics 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. It has been reported that the control of pH or
temperature, though advantageous to the operation of the process, would
be economically impractical (82) .
Several others (86) utilized a carbon slurry to treat municipal wastes.
They reported a tendency of the compacted slurry in the quiescent
concentrator to form a gelatinous mass. It became necessary to agitate
the gel to reliquefy it for easy removal.
The use of powdered carbon columns was also studied (82) . The
researchers 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
efficiencies. Polyelectrolyte flocculation was determined to be the
most economical method of recovering spent powdered carbon. It was also
determined that a suspended solids concentration of 500 mg/1 or more
must be maintained in the carbon slurry to assure flocculation
efficiency.
148
-------
Table 40
RESULTS OF ACTIVATED CARBON PILOT PLANTS
TREATING UNBLEACHED KRAFT MILL EFFLUENT
Description Of
Carbon Process
Hydraulic
Load, gpm/ft
Carbon
Contact Time, Min.
BOD, mg/1
TOC, mg/1
Turbidity, J.U.-
Color, Units
Fresh Carbon
Dosage
Ib. carbon/
1000 gal.
?H
Columns
Preceded By
Biological
Oxidation &
Clarification
Inf.
2
Eff. .
.13
Granular
140
148
740
57
212
8
Removal
61Z
71Z
Columns
Preceded By
Primary
Clarification
Inf.
1.
Eff.
42
1
Granular
220
925
83
185
20.5
Removal
62Z
80Z
Columns
Preceded By
Prinary '
Clarification
Inf.
0
Eff . i Removal
71
Granular
310
1160
121
202
28
61Z
83%
Columns
Preceded By
Lime Treatment
& Clarification
Inf.
1.4
Eff.
2
Granular
103
26Z Rei
177
252
Aval
100
5-15
76
2.5
11.3
Removal
44Z
70Z
FACET System
Inf.
N.
Eff. 1 Sa=oval
A.
Intermediate
158
157
101
73*
3.9
1
36%
542
*?Utered
-------
Pilot plant tests on domestic secondary effluent were conducted (83) and
results showed that organic matter which was adsorbed on the carbon went
septic and produced a breakthrough of turbidity and organic matter. An
H2S odor in the treated effluent was observed which indicated some
biological activity within the first two feet of the carbon column which
caused some plugging problems if the columns were not backwashed every
day or two. They felt because of the low dissolved oxygen concentration
that the biological activity was anaerobic. Chlorination of the
influent to the carbon columns appears to eliminate sliming problems
caused by biological activity within the columns.
Lower rates of adsorption, were reported (69) , 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 28 (87) 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 waste water effluents. Chlorina-
tion has also been found useful for the removal of ammonia nitrogen and
odors from waste water. However, the use of chlorination for the
removal of trace refractory organics is not a well-documented process.
Several researchers (78) report that the costs indicate that chlorine
oxidation is not competitive with activated carbon adsorption for
removal of relatively 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 BODJ5 in the absence of
adsorption equipment. No literature has been found that directs its
attention specifically to the applicability of chlorination to the pulp
and paper industry. However, a demonstration project has recently been
completed on the chlorination of pulp and paper mill effluents and the
results should soon be available.
A seven-month study of chlorination was conducted (88) of approximately
303 million liters per day (80 mgd) of effluent from a conventional
activated sludge process treating municipal waste water. It was
determined that chlorination caused a substantial reduction in the BODS.
The BODS 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 EOD5 was noticeably improved. The researcher also
150
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FIGURE 28
ECONOMY IN SCALE - CARBON ADSORPTION SYSTEMS
INFLUENT COD = 50O-700mq/l
(EFFLUENT COD 150 mq/l)
0
INFLUENT COD 200mq/l
(EFFLUENT COD 50 mq/l)
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.
Costs include initial carbon inventory, carbon
handling system, and regeneration facilities.
-------
monitored the suspended solids, POU, and TOD. He found that the
suspended solids concentration increased about 20 percent. He theorized
that some of the soluble compounds were "precipitated" into a suspended
state by the chlorine. The PO<* and TOD were not significantly affected
by chlorination. Chlorine oxidation, catalyzed with ultraviolet
radiation, was studied for the treatment of domestic waste water (89).
They found that chlorine will slowly oxidize only a small fraction of
dissolved organic material in the dark, but in the presence of
ultraviolet radiation, rapid elimination of large amounts of COD and TOC
is possible. The most important factor involved in the process was the
selection of the source of radiant energy. Short-wavelength radiation
(below 300 mu) is more effective than long-wavelength radiation in
promoting the chlorine oxidation process. Radiation of 254 mu was about
six times more effective than polychromatic radiation between 300-370
mu. 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 treatment is
dependent on the penetration achieved by the ultraviolet radiation.
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 has been observed.
Mercury-arc lamps are 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.
Chlorine concentrations above 5 mg/1 produced 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 municipal
waste water 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. Others (90) have determined that ozone effectively reduces the
152
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COD and TOC content of effluents from municipal waste water treatment
plants, as well as odors, color, and pathogenic organisms.
Residual ozone decomposes very rapidly. It has a half-life in drinking
water of about 20 minutes. Because of the instability of ozone, it must
be produced at its point of use. The most common methods of producing
ozone are (90):
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 (90) .
Because of the expense involved, the use of ozonation to oxidize
organics has not in the past been considered a practical form of
tertiary treatment. No investigation of its applicability to the pulp
and paper industry has been found.
Laboratory scale tests were conducted (90) with about 37.85 liters per
hour (10 gallons per hour) on the use of ozone to oxidize organics
remaining in effluent from municipal secondary waste water 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 (90).
Low pH resulted in lower reaction rates, but higher ozone utilization
efficiencies.
Ozone oxidizes many compounds which resist biological oxidation.
However, the most readily bio-oxidizable organics also consume ozone the
most efficiently (90). Chemical clarification prior to ozonation will
remove a portion of the TOC that is resistant to oxidation by ozone
resulting in lower final TOC level and less ozone consumption.
Ozonation efficiency was high when COD and TOC concentrations were high.
153
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However, the effluent had an unacceptably high COD and TOC content. It
was concluded that effluents having high organic content (COD above UO
mg/1) are more economically treated by a combination of chemical
clarification and ozonation. Effluents with a low organic content
require only ozonation.
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*
It has been reported (91) that ozonation, catalyzed with activated
Raney-Nickel removed 85 percent of the COD and 60 percent of the TOC
from secondary treatment effluents in two hours under favorable condi-
tions.
Also, it has been concluded (90) 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 (90). 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,
concurrent ozonation.
154
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NEUTRAL SULFITE SEMI-CHEMICAL-SODIUM BASE
Internal Technologies
Water reuse and upset control in this subcategory of mills have been
described in detail in the literature (29) (33) (92). 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
(33).
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:
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 daily wood pulp production of 181.U metric tons (200 short tons),
some 90,800 kilograms (200,000 pounds) of dissolved solids are produced.
Approximately, 68,100 kilograms (150,000 pounds) of this amount are
removed in the combined screw pressate and digester blow liquors,
reduced to 21 percent solids by indirect evaporation, and supplied to
the fluidized bed reactor. Additional solubles are introduced into the
overall system via the 86.2 metric tons (95 short tons) of waste paper
utilized daily.
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.
155
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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.
<*. Redundant installation of key pumps and other equipment to avoid
losses due to equipment failure and routine maintenance.
5. Monitoring systems to alert operating personnel of potential and
actual spills so that corrective action can be promptly initiated.
6. Storage lagoons located prior to biological treatment may be
provided to accept longer term shock loads.
7. Personnel should be trained to avoid such spills where possible,
and to take immediate corrective action when they occur.
It will be recognized that most of these techniques are the same in
principle, if not in detail, as 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 facilities and
final effluent quality.
One mill may soon install a reverse osmosis system to handle unavoidable
final spills (93). 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 (29) 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 (29) has delineated these problems as process water
usage approached 6260 liters/kkg (1500 gal/ton):
156
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1. Variable paper quality due to wet streaks in wet felts
2. Decreased wet felt life due to plugging from fines
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/kkg (2000 gal/ton) from 6260 liters/kkg (1500 gal/ton).
The techniques and methods of internal controls for the stock
preparation and paper machine operations as described for unbleached
kraft mills are equally applicable to this subcategory.
External Technologies
Although there are variations in concentrations and specific waste
constituents, the general classes of compounds which occur in these
wastes are similar to those occurring in unbleached kraft wastes. Thus,
treatability and treatment systems for NSSC-sodium are similar to the
systems discussed previously in unbleached kraft. Specifically, the
discussions of suspended solids removal and BOD5 removal apply to NSSC-
sodium mills also. Data on two NSSC sodium base mills which have
secondary treatment and for which secondary treatment effluent data were
available are shown in Tables 41 and 42. Specifically, Table 41 shows
production, flow, type of treatment, and the TSS analytical measurement
technique for each mill. Table 42 shows BOD5 and TSS data for the
mills* raw waste and final effluents (Note: AA is the annual average of
daily values and MM is the maximum monthly average of daily values) .
The data generally represent a full year's operation and have been
derived from mill records by either EPA or the NCASI.
As shown in Table 24, color removal techniques on NSSC waste waters
primarily include reverse osmosis. Reverse osmosis has been extensively
investigated for possible application within the pulp and paper
157
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01
oo
* Clarifier-ASB-Clarifier
return sludge
TABLE 41
MILL DATA
NSSC - SODIUM BASE
Mill
NS-1
NS-2
Production-AA
kkg/day
(tons/day)
336(370)
521(574)
Flow-AA
kiloliters/kkg
(1000 gal/ton)
44.6(10.7)
48.8(11.7)
Treatment
Detention (Days)
ASB SO
3 14
5* 0
Aeration
in HP
ASB
515
1200
TSS
Methods
SM
SM
-------
TABLE 42
MILL EFFLUENT DATA
NSSC - SODIUM BASE
Mill
NS-1
NS-2
*mg/l
Raw
AA
BODS
8.5(17)
31(62)
Waste
AA
TSS
8.5(17)
17.5(35)
(All values in kg/kkg (Ibs/ton) except as noted)
Final Effluent
AA
BODS
0.75(1.5)
3.2(6.4)
MM
BODS
1.3(2.7)
4.3(8.7)
MM AA
BODS* TSS
1.6(3.2)
97 13.3(26.6)
MM
TSS
3.2(6.5)
18.7(37.5)
MM
TSS*
424
-------
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 initial work with membranes was in conjunction with an electrodia-
lysis system (94). Electrodialysis investigations of pulp liquors
provided important background on new membrane processes such as ultra-
filtration 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 percent suspended solids (95) ' (96) .
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 Protection
Agency (94). Their studies led to confirming trials conducted in field
demonstrations ranging from 18,900 to 189,300 liters per day (500 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)
4. Kraft Bleach Effluent (also Kraft Rewash Water)
5. Chemi-mechanical 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 (94). 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 (95). This study
included the operation of proprietary 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
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
160
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process purposes (93) . The concentrated stream would be directed to the
fluid!zed 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 (96). 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 (94) (97).
i
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 (98). While hyperfiltration is very effective in removing
color and macromolecular organic compounds, certain lower weight
molecular organic compounds are not rejected by the reverse osmosis
process.
If color removal only is necessary, the ultrafiItration as described
previously which is not as effective as hyperfiltration in removal of
organic matters and solids, but is very effective in color removal,
would be satisfactory (97) .
The efficiency of the reverse osmosis process for NSSC pulp and
papermaking waste waters is presented in Table U3 (96).
The waste flows had to be pretreated by passage through a UO mesh screen
and the temperature adjusted to a safe operating range to protect the
cellulose acetate membranes (below UO°C) (96).
The extensive pilot testing undertaken by a sodium base NSSC mill showed
general rejections by the reverse osmosis process as follows (9U):
Total Solids 99.7X
BOD5 98.6%
Color-Optical Comparator 99. 6X
Color-Spectrophotometer 99.8%
The work by the Institute of Paper Chemistry indicated that fouling of
reverse osmosis membranes by suspended particles, colloidal suspensoids
161
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TABLE 43
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 87-95 95-99Ca 99 80-90
NSSC 96-98 87-95 96-98 82-95Na 99+ 72-92
Ammonium Sulfite 93-96 77-94 92-97 92-98NH3 99 65
Kraft Bleach 91-99 85-97 97-99 83-95Na 99+
162
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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 (95) . 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
(95). 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 preferable when
a high degree of salt removal is not required (97). In addition,
ultrafiltration membranes are more open than the more tight reverse
osmosis (hyperfiltration) membranes and while rejection for colored
ligonsulfonates is high, other components are rejected to a much less
satisfactory degree. Research is being carried out to develop improved
rejection with ultrafiltration membranes because they have higher flux
rates than hyperfiltration and the advantages of simplified equipment
design (94). 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 (96) . In addition, membrane development
should include a capability for operating at wider ranges of pH and
temperature (96) 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 (64) (97) (99) .
163
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NSSC-AMMONIA BASE
Internal Technologies
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 unbleached 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 is
to channel the primary cooling water into the weak black liquor as it
enters the evaporators (100), thus lowering the pH and inhibiting con-
version of ammonium to ammonia. The techniques and methods of internal
controls for the stock preparation and paper machine operations as
described for unbleached kraft mills are equally applicable to this
subcategory.
External Technologies
Although there are variations in concentrations and specific waste
constituents, the general classes of compounds which occur in these
wastes are similar to those occurring in unbleached kraft wastes. Thus,
treatability and treatment systems for NSSC- ammonia are similar to the
systems discussed previously in unbleached kraft. Specifically, the
discussions of suspended solids removal and BOD5 removal apply to NSSC-
ammonia mills also. Data on one NSSC ammonia base mill which has
secondary treatment and for which secondary treatment effluent data were
available is shown in Tables UU and 45. Specifically, Table UU shows
production, flow, type of treatment, and the TSS analytical measurement
technique for the mill. Table 45 shows BOD5 and TSS data for the mills'
raw waste and final effluents (Note: AA is the annual average of daily
values and MM is the maximum monthly average of daily values). The data
represent a full year's operation and have been derived from mill
164
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Production-AA
kkg/day
Mill (tons/day)
N-l
390(430)
TABLE 44
MILL DATA
NSSC - Armonia Base
Flow-AA Treatment
kiloliters/kka Detention(Days)
(1000 gal/ton) ASB
32.5(7.8)
12
SO
3-14
Aeration
in HP
ASB
500
TSS
Method
NSM
165
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TABLE 45
MILL EFFLUENT DATA
NSSC - Ammonia Base
(All values in kg/kkg(lbs/ton) except as noted)
Raw Waste Final Effluent
AA AA AA MM MM AA MM MM
Mill BOD5 TSS BOD5 BODS BOD5* TSS TSS TSS*
N-l 33.7(67.5) 17(34) 5.8(11.7) 13.1(26.3) 335 4.2(8.5) 9.4(18.9)
*mg/l
Note: TSS: NSM
166
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records by EPA. As discussed for NSSC - sodium base, removal of color
by reverse osmosis is equally applicable to NSSC - ammonia base mills.
As mentioned previously, ammonia base NSSC mill effluents contain high
concentrations of ammonia for which removal technologies have not yet
been demonstrated for the pulp and paper industry. A discussion of
potential ammonia removal technologies follows.
Ammonia Nitrogen Removal
A selective ion exchange system for the removal of ammonia nitrogen has
been developed (78) (101) 102) but has not been applied to ammonia base
NSSC mills. The process usep 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
(78) (101) (102). Work showed that the ammonia can be destroyed by
electrolysis of the regenerant, which results in the production of
chlorine that reacts with the ammonia to produce nitrogen gas (102). A
preliminary design report was prepared 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 (78) (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, 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
waste waters with high Mg+2 concentrations may require clarification of
the regenerate to avoid plugging of the bed with Mg (OH)2 (102) . In
addition, it has been stated that secondary effluents may require clari-
fication by plain filtration to prevent fouling of the zeolite beds
(78).
167
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Ammonia removal by selective ion exchange is probably best suited to
areas where prolonged periods of freezing weather are encountered and
where very high degrees of ammonia removal must be maintained. Air-
stripping and biological nitrification-denitrification may be used in
the warmer climates at a lower cost, but at a somewhat lower efficiency.
Nitrification-denitrification refers to the biological treatment process
utilized to convert nitrogen compounds (generally ammonia) to nitrates
and nitrates to nitrogen gas. The biological nitrification-denitrifica-
tion process has been extensively investigated and reported (78) (103)
(10U) (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.
The following factors will influence nitrification (87):
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 temperature is
about 32°C.
U. Growth rate of nitrifiers is reduced by chlorates, cyanides,
alkaloids, mercaptans, urethanes, guanidines, methylamine, and
nitrourea.
The denitrifying bacteria convert the nitrite and nitrate nitrogen
resulting from the nitrification reaction to nitrogen gas.
The three basic requirements for denitrification to proceed are the
following (107):
1. An organic carbon source which can be utilized by the
dentrifying bacteria. "*-
2. An anaerobic environment.
3. A pH of about 6.5.
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);
168
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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.
Discussion of two stripping towers that have been designed for treatment
of waste waters is given below. The most well known work done with air
stripping of ammonia has been done on municipal wastes at Lake Tahoe
(75). A countercurrent stripping tower, 7.62 meters (25 feet) high,
1.83 meters (6 feet) wide, and 1.22 meters (4 feet) in depth was used to
investigate the various parameters affecting air stripping of ammonia.
The results of these are shown in Figures 29, 30, 31. It is apparent
from these figures that the design of air stripping towers can be such
as to accommodate any desired ammonia removal up to 90-95 percent
removal when ambient air temperatures are above 20°C. As reported (87) ,
the efficiency 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. In addition, a stripping
tower has been used in conjunction with barometric type evaporator
condensers for treatment of final and combined condensates in at least
one pulp and paper mill. The mill at 771 metric tons (850 short tons)
removed about 6 kg/metric ton (12 Ibs/ton) and reduced raw water intake
by 30,200-37,800 kiloiters/day (8-10mgd).
The limitations of the use of ammonia stripping towers were first
realized with the winter operations at Lake Tahoe. These limitations
are outlined 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 costs.
3. A calcium carbonate scale formation results on the tower because
the lime treated wastes are saturated with CaCO3. 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 packing.
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.
169
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Figure 29
EFFECT OF TOWER DEPTH ON AMMONIA REMOVAL
24' Depth
_J I0°
/
//
^0
/
>*' f
~T1
If
. //A
/ /
II
1
OL if/
r\\L
•* f
u
j«S__— ,
/v Xs s
fa"*'
C/ ^^
V
/
^ A
A H^
ts " •*!» ** *]'^ """' "~ \*"y™ ^v>
v)" >vO <>' ~ 1 £> i^ -0— 3
0
A
»•
s^
A
\
3® <
-^***A
^
1 VMJ
Depth '
* ** —
12' Depth
.
1 ;
^— * • "
A
200 400 600 800
CUBIC FEET AIR/GALLON TREATED
170
-------
Fi gyre 3C
EFFECTS OF HYDRAULIC LOADING ON AMMONIA REMOVAL AT VARIOUS DEPTHS
100
i 80
UJ
o:
< so
o
h-
2
O
UJ
CL
40
20
0
24' Depth
201 Depth
12' Depth
1.0 2.0 3.0 4.0 5.0 6.0
SURFACE LOADING RATE (GPM/FT2)
-------
Figure 31
EFFECTS ON PACKING SPACING ON AMMONIA REMOVAL
l/2 x 2 In. Packing (redwood slats)
4x4In. Packing (plastic truss bars)
Note'24 Ft. Packing Depth
500 1,000 1,500 2,000 2,500 3,000 4£GO
CUBIC FEET AIR/GALLON TREATED
-------
KRAFT-NSSC (CROSS RECOVERY)
As shown in Tables 23 and 24, internal and external control technologies
applicable to unbleached kraft mills also apply to kraft-NSSC mills with
cross recovery and have been discussed previously. Data on four
unbleached kraft-NSSC (cross recovery) mills which have secondary
treatment and for which secondary treatment effluent data were available
are shown in Tables 46 and 47. Specifically, Table 46 shows production,
flow, type of treatment, and the TSS analytical measurement technique
for each mill. Table 47 shows BODJ3 and TSS data for the mills' raw
waste and final effluents (Note: AA is the annual average of daily
values and MM is the maximum monthly average of daily values). The data
generally represent a full year's operation and have been derived from
mill records by either EPA or the NCASI.
173
-------
T3\BLE 46
PELL DATA
UNBLEACHED KRAFT-NSSC (CROSS RECOVERY)
Production-AA Flow-AA Treatment Aeration
kkg/day kiloliters/kkg Detention Time (Days) in HP - TSS
Mill (tons/day) (1000 gal/ton) ~A§B ScfASB Method
X-l 1110(1224) 57.5(13.8) 7.5 0 900 SM
X-2 635(700) 58.8(14.1) 7 0 460 NSM
X-3 1824(2011) 43.4(10.4) 18 4 1000 34
X-4 1215(1340) 74,3(17.8) 11 5 1060 94
-------
TABLE 47
MILL EFFLUENT DATA
UNBLEACHED KRAFT-NSSC (CROSS RECOVERY)
(All values in kg/kkg (Ibs/ton) except as noted)
Raw Waste Final Effluent
AA
BODS
24(48)
16.9(33.9)**
16.3(32.6)
AA
TSS
28.5(57)
9.7(19.4)**
13.4(24.9)
AA
BODS
2.7(5.5)
4.8(9.7)
3.3(6.7)
2.7(5.5)
MM
BODS
3.5(7.1)
6.0(11.9)
4.7(9.5)
3.9(7.8)
MM
BODS*
66
100
105
51
AA
TSS
5(10)
3.7(7.5)
2.8(5.6)
2.9(5.7)
MM
TSS
6.4(12.8)
5.7(11.4)
3.4(6.9)
5.1(10.3)
MM
TSS*
118
98
72
69
Mill
X-l
X-2
X-3
-> X-4
-j
en
*mg/l
**Primary Treatment Effluent
-------
PAPERBOARD FROM WASTE PAPER
Internal Technologies
A paperboard from waste paper mill utilizes water in its process
exclusive of steam generation for the following purposes:
1. Water used for the preparation and transport of fiber through
the papermaking process. This is generally recycled water; however,
process water that escapes from one stock system to another represents a
contribution to the mill effluent to the extent that this intersystem
loss occurs. Reduction of the loss of process water from one stock
system to another is one type of in-plant control that can be utilized
to reduce the raw waste load generated by many mills in this category.
2. Shower water used principally to remove the build-up of fibrous
materials on the wet end of the machine which is detrimental to the
formation of the product. This water enters the system via shower
nozzles and accounts for the largest contribution to the volume of raw
waste water generated. The use of recycled process water instead of
fresh water for this purpose is essential if major reductions in waste
loads generated are to be realized.
3. Water used to permit process equipment to perform its design
function. Typical applications are the seal and cooling waters used on
pumps, agitators, drives, bearings, vacuum pumps, and process controls.
This represents a significant contribution to the volume of waste water
generated by the process. In-plant control systems have been developed
in many mills that minimize or eliminate this source of waste water
generation. The introduction of this source of water to the process
system is generally under automatic control and will, in the event of
undetected control malfunction, contribute substantially to the waste
water volume generated by a mill. Reliable control of these sources of
waste water must be included in any in-plant water control system
designed to minimize the waste load generated by a mill.
U. Water utilized as non-contact cooling water. The segregation
and discharge of this water without treatment has been achieved by many
mills and represents in-plant control technology which is essential if
near total recycle of process water is a goal.
The water utilization and control technologies described if implemented
would make possible very significant reductions in waste loads generated
by mills in this category. There are a number of mills that have
achieved near total recycle of process water using these or variations
of these control technologies. However, for many mills in the industry
near total recycle could present a number of production related
problems. Those mills that use predominately corrugated waste paper in
their furnish could experience excessive dissolved solids buildup in the
process water systems which may not be the case for those mills that use
predominantly news, mixed, and magazine waste papers. Corrugated waste
176
-------
paper contains adhesives that are relatively high in starch content.
This adhesive is dissolved during the stock preparation process and due
to its solubility becomes part of the process water system.
The presence of these dissolved solids has no significance for a mill
discharging 41,700 liters/kkg (10,000 gal/ton) or more. However, for a
mill practicing near complete recycle the attending dissolved solids
buildup could create production problems of considerable magnitude.
Similar problems could be experienced by those mills that employ on
machine coating when near complete process water recycle systems are
implemented. Mills that produce food board from a waste paper furnish
may experience increasing problems in meeting regulations established by
government health authorities due to objectionable odors or other
considerations attributable to the implementation of extensive process
water recycle concepts.
These are a few of the product grades that have increasing significance
as near complete recycle of process water is considered by many mills in
this subcategory. Mills that produce a similar grade of product for
most of their production time will experience fewer problems if
extensive recycle of process water is implemented. However a majority
of mills in this subcategory produce these and many other production
grades, including food board, all of which can be affected to a greater
or lesser extent if a near total recycle of process water system has
been implemented.
As shown in Table 23, only a few of the internal control technologies
(as discussed for unbleached kraft) for the pulping operation apply.
However, all of the control technologies for the stock preparation and
paper machine operations apply as were discussed previously for
unbleached kraft.
External Technologies
Since waste paper is fiberized by hydraulic and mechanical means there
are no comparable chemical constituents in the mill effluents to the
other subcategories resulting from pulping processes. However, the
waste treatability is similar to that of the other subcategories, and
the external technologies for primary and secondary treatment as
discussed previously also apply to paperboard from waste paper mills.
Data on nine paperboard from waste paper mills, eight of which have
secondary treatment and for which secondary treatment effluent data were
available, are shown in Tables 48 and 49. Specifically, Table 48 shows
production, flow, type of treatment, and the TSS analytical measurement
technique for each mill. Table 49 shows BOD5 and TSS data for the
mills' raw waste and final effluents (Note: AA is~the annual average of
daily values and MM is the maximum monthly average of daily values).
The data generally represent a full year's operation and have been
derived from mill records by either EPA or the NCASI.
177
-------
48
MILL DATA
PAPERBOARD FROM WASTE PAPER
Production-AA
kkg/day
Mill (tons/day)
P-15 145(160)
P-16 272(300)
P-17 440(485)
P-18 245(270)
P-19 56 (62)
P-20 91(100)
P-21 145(160)
P-22 91(100)
P-23 73 (80)
Flow-AA
kiloliters/kkg
(1000 gal/ton)
68.4(16.4)
12. 1( 2.9)
19. 6( 4.7)
38. 8( 9.3)
5.0( 1.2)
47.5(11.4)
9.5( 2.3)
38. 8( 9.3)
139.3(33.4)
Treatment
C-ASB
C-ASB-C
ASB-SO
C-AS-C
C-AS-C
C-ASB-HP
C-ASB
ASB-DAF
DAP
Aeration
in HP
100
300
120
40
120
60
TSS
Method
NSM
SM
SM
SM
SM
SM
SM
SM
SM
CO
-------
TABLE 49
Mill
P-15
P-16
P-17
P-18
P-19
P-20
P-21
P-22
P-23
MILL EFFLUENT DATA
PAPERBOARD FROM WASTE PAPER
Raw Waste
AA
BODS
16.2(32.5)
10(20)
6(12)
5.5(11)**
4(8)
7.5(15)
9.5(19)
9(18)
12.5(25)
AA
TSS
72.5(145)
9(18)
35(70)**
4.7(9.5)
6.5(13)
2.8(5.6)
7.5(15)
81(162)
*mg/l
** Primary Treatment Effluent
.ues kg/kkg (Ib/ton) except as noted)
AA
BODS
1.6(3.3)
0.25(0.5)
0.55(1.1)
0.15(0.3)
0.1(0.2)
1.1(2.2)
0.3(0.6)
1.0(2.0)
4.0(8.0)
MM
BODS
2.4(4.9)
0.7(1.4)
1.6(3.2)
0.35(0.7)
0.15(0.3)
1.9(3.8)
0.7(1.4)
1.2(2.4)
7.1(14.3)
MM
BODS*
52
58
82
09
17
42
74
31
21
Final Effluent
AA
TSS
6.3(12.7)
1.3(2.6)
0.8(1.6)
0.9(1.9)
1.0(2.0)
1.4(2.8)
0.55(1.1)
1.8(3.6)
4.5(9.0)
MM
TSS
8.7(17.4)
3.6(7.3)
2.0(4.0)
1.5(3.1)
2.1(4.2)
2.7(5.4)
1.7(3.5)
2.9(5.9)
9.4(18.9)
MM
TSS*
223
301
103
40
383
61
186
75
28
-------
In the case of many paperboard from waste paper mills which discharge
into public sewerage systems, effluent treatment sludges are handled
with those contributed by sanitary sewage. Methods are set forth in
FWPCA Manual of Practice No. 20 (107) and their effects on the overall
process are described in the literature (108).
Sludges from paperboard from waste paper mills can generally be
thickened to a consistency in excess of four percent dry solids by
prethickening. If activated sludge from secondary treatment is included
this figure can be somewhat lower.
180
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IRRIGATION AND LAND DlgPQSAL^OF^EFFLUENTS
Total mill effluents 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
turpentine 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, BOD5, 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, and (3) the potential for imparting taste, odors, or other
undesirable characteristics to groundwaters. In some instances, this
process is applied only during the critical 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 (110).
An assessment of the effectiveness of irrigation on crop growth and the
parameters for application of water, BODS, cellulose, and sodium for
soils of different character and textures are set forth.
Unbjj,eached Kraft
Although considerable demonstration work has been done on the use of
kraft mill effluents for irrigating fodder crops, corn, 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
(111) which indicate the suitability of such effluents for irrigation.
181
-------
However, after applications and trials made to date, this technique has
received only minimal acceptance by these mills on a full scale (12).
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
8,3U6 liters/kkg (20,000 gal/ton) of product, 2,025 hectares (5^000
acres) of land would be required for a 970 metric tons per day (1,000
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 treatment. This
procedure would also necessitate the mill engaging in a business
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
Land disposal of both spent cooking liquor and wash and machine waters
from NSSC mills has been described (112). 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 increasing 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.
Paperboard from Waste Paper
There has been no use of irrigation for the disposal of paperboard from
waste paper 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
requirements.
182
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SECTION VIII
COSTS, ENERGY, NON-^WATER QUALITY ASPECTS
AND IMPLEMENTATION REQUIREMENTS
RATigNALE^FOR DEVELOPMENT OF COgTS
This section of the report summarizes the costs of internal and external
effluent treatment associated with technology levels of BPCTCA, BATEA,
and New Source Standards of Performance. The cost functions used are
for conventional treatment methods based on industry experience with
full scale installations and equipment suppliers' estimates. For more
advanced processes, where full scale installations are few or
nonexistent, the cost estimates are largely based on experience with
pilot installations and on estimates from and discussions with equipment
suppliers.
It should be recognized that actual treatment costs vary largely from
mill to mill depending upon the design and operation of the production
facilities and local conditions. Furthermore, effluent treatment costs
reported by the industry vary greatly from one installation to another,
depending upon bookkeeping procedures. The estimates of effluent
volumes and treatment methods described in this section are intended to
be descriptive of the segments of the industry that they cover.
However, the industry is extremely heterogeneous in that almost every
installation has some uniqueness which could be of importance in
assessing effluent treatment problems and their associated costs.
For each technology level, the cost of effluent treatment has been
summarized for five case studies with regard to type and size of mill.
The case situations studied are as follows:
Production Capacity
Type of Mill kkg/day (tons/day)
Unbleached kraft (linerboard) 907 (1000)
NSSC - Sodium base 227 (250) *
NSSC - Ammonia base 227 (250) *
Kraft - NSSC (Cross Recovery) 907 (1000)
Paperboard from Waste Paper 91 (100)
* includes use of 50 tons/day waste paper
Development of Effluent Treatment Costs
183
-------
costs of effluent treatment are presented as investment and annual
costs. The annual costs are further broken down into capital costs and
depreciation. Investment costs are defined as the capital expenditures
required to bring the treatment or control technology into operation.
These include the traditional expenditures such as design, purchase of
land and all mechanical and electrical equipment, instrumentation, site
preparation, plant sewers, all construction work, installation and
testing, etc.
The capital costs are the financial charges on the capital expenditures
for pollution control.
The depreciation is the accounting charges which reflect the
deterioration of a capital asset over its useful life. Straight line
depreciation has been used in all case study cost calculations.
Operation and maintenance costs are those costs required to operate and
maintain the pollution abatement equipment. They include labor, parts,
chemicals, energy, insurance, taxes, solid waste disposal, quality
control, monitoring and administration, etc. Productivity increases or
by-product revenues as a result of improved effluent control are
subtracted so that the operation and maintenance costs reported are the
net costs.
All costs in this report are expressed in terms of August 1971 prices.
This is comparable to the following cost indexes:
Indexes Index 3 August 1971
EPA Treatment Plant Construction Cost 164.5
Index (1957^59 = 100)
EPA Sewer Line Construction cost 166.8
Index (1957-59 = 100)
Engineering News Record (ENR)
Construction Cost index (1913 =100) 1614
ENR Labor Cost Index (1949 = 100) 420
Effluent treatment or control technology is grouped into internal and
external measures. The internal and external treatment technologies
which were used to develop treatment costs are shown below. It should
be noted that the treatment systems that are shown below may be
different than the identified treatment systems in Sections IX, X, and
XI. The reason for these differences is that costs were developed for
the most expensive case (within practical limits) in order to determine
the impact upon the industry.
Available methods for reduction of pollutant discharges by internal
measures include effective pulp washing, chemicals and fiber recovery.
184
-------
treatment and reuse of selected waste streams and collection of spills
and prevention of "accidental" discharges. Internal measures are
essentially reduction of pollutant discharges at their origin and result
in recovery of chemicals, by-products, and in conservation of heat and
water.
As discussed in Appendix III, the cost of BPCTCA, BATEA, and NSPS for a
model mill within each subcategory were developed using the internal and
external control technologies in Tables 50 and 51, respectively. It
should be noted that the resulting costs include all of the internal
technologies whereas, it is not expected that all of the internal
technologies need to be installed for a particular mill to meet the
limitations. Thus, the resultant costs are for the most expensive
situation in order to determine the maximum economic impact.
The costs of the effluent treatment and resulting pollutant reductions
are shown in Tables 52, 53, 5U, 55, and 56 for unbleached kraft, NSSC-
sodium base, NSSC-ammonia base, unbleached kraft-NSSC (cross recovery) ,
and paperboard from waste paper subcategories, respectively.
The treatment unit operations are grouped into pre-, primary, secondary,
and tertiary treatment and sludge dewatering and disposal.
Pretreatment includes those processes which are used as required to
prepare the effluent for the subsequent treatment steps.
Primary treatment is designed to remove suspended solids and is usually
the first major external treatment step.
The primary purpose of secondary treatment is to remove soluble BOD5..
The tertiary treatment steps are designed to remove suspended solids and
BOD5 to degrees which are not obtainable through primary and secondary
treatment processes, or to remove substances which are refractory to the
primary and secondary treatment steps.
185
-------
Table 50
Internal Control Technologies Used in the
Development of Costs
Unbleached Kr aft
BPCTCA
BATEA
NSPS
addition of spill collection provisions for chemicals and fibers
installation of low volume, high pressure self cleaning showers on
all paper machines
filtering and reuse of press waters
pressure screening (hot-stock)
segregation and reuse of white waters
collection and reuse of vacuum pump seal waters
installation of savealls
gland water reduction
expanded process water reuse
separation of cooling water and recovery of heat
reuse of fresh water filter backwash
control of spills whereby major pollutional loads bypass
the waste water treatment system to a retention basin and
are ultimately either reused, gradually discharged into the
treatment system, or treated separately
reduction of pulp wash and extraction water
expanded process water reuse
separation of cooling water and recovery of heat
reuse of fresh water filter backwash
control of spills whereby major pollutional loads bypass
the waste water treatment system to a retention basin and
are ultimately either reused, gradually discharged into the
treatment system, or treated separately
reduction of pulp wash and extraction water
186
-------
Table 50 (Cont'd)
NSSC-Sodium
BPCTCA
- addition of liquor recovery system
installation of low volume, high pressure self cleaning
showers on paper machines
filtering and reuse of press water
segregation and reuse of white waters
collection and reuse of vacuum pump seal waters
installation of savealls
gland water reduction
BATEA
NSPS
expanded process water reuse
separation of cooling water and recovery of heat
reuse of fresh water filter backwash
control of spills whereby major pollutional loads bypass
the waste water treatment system to a retention basin and
are ultimately either reused, gradually discharged into the
treatment system, or treated separately
reduction of pulp wash and extraction water
expanded process water reuse
separation of cooling water and recovery of heat
reuse of fresh water filter backwash
control of spills whereby major pollutional loads bypass
the waste water treatment system to a retention basin and
are ultimately either reused, gradually discharged into the
treatment system, or treated separately
reduction of pulp wash and extraction water
187
-------
Table 50 (Cont'd)
NS SC-Ammon i a
BPCTCA
segregation and reuse of white waters
collection and reuse of vacuum pump seal waters
installation of savealls
gland water reduction
BATEA
NSPS
expanded process water reuse
separation of cooling water and recovery of heat
reuse of fresh water filter backwash
control of spills whereby major pollutional loads bypass
the waste water treatment system to a retention basin and
are ultimately either reused, gradually discharged into the
treatment system, or treated separately
reduction of pulp wash and extraction water i
expanded process water reuse
separation of cooling water and recovery of heat
reuse of fresh water filter backwash
control of spills whereby major pollutional loads bypass
the waste water treatment system to a retention basin and
are ultimately either reused, gradually discharged into the
treatment system, or treated separately
reduction of pulp wash and extraction water
188
-------
Table 50 (cont'd)
Unbleached Kraft-NSSC (Cross Recovery
BPCTCA
addition of spill collection provisions for chemicals and fibers
- installation of low volume, high pressure self cleaning showers on
all paper machines
filtering and reuse of press waters
- pressure screening (hot-stock)
- collection and reuse of vacuum pump seal waters
installation of savealls
gland water reduction
BATEA
NSPS
expanded process water reuse
separation of cooling water and recovery of heat
reuse of fresh water filter backwash
control of spills whereby major pollutional loads bypass
the waste water treatment system to a retention basin and
are ultimately either reused, gradually discharged into the
treatment system, or treated separately
reduction of pulp wash and extraction water
expanded process water reuse
separation of cooling water and recovery of heat
reuse of fresh water filter backwash
control of spills whereby major pollutional loads bypass
the waste water treatment system to a retention basin and
are ultimately either reused, gradually discharged into the
treatment system, or treated separately
reduction of pulp wash and extraction water
189
-------
Table 50 (Cont'd)
Paper-board from Waste Paper
BPCTCA
BATEA
NSPS
land disposal of junk materials
installation of low volume, high pressure self cleaning
showers on paper machines
filtering and reuse of press water
segregation and reuse of white waters
collection and reuse of vacuum pump seal waters
installation of savealIs
gland water reduction
land disposal of junk materials
installation of low volume, high pressure self cleaning
showers on paper machines
filtering and reuse of press water
segregation and reuse of white waters
collection and reuse of vacuum pump seal waters
installation of savealls
gland water reduction
land disposal of junk materials
installation of low volume, high pressure self cleaning showers on
paper machines
filtering and reuse of press water
segregation and reuse of white waters
collection and reuse of vacuum pump seal waters
installation of savealls
gland water reduction
190
-------
Table 51
External Control Technologies Used in the
Development of Costs
BPCTCA
Screening, primary, and secondary treatment are provided to total mill
effluents for all subcategories, where the screening is by bar screens
and primary sedimentation in mechanical clarifiers.
Secondary treatment is provided by nutrient addition and one or two
stage biological treatment. An emergency spill basin is installed prior
to the secondary treatment step.
All mill effluents receive foam control treatment, monitoring and
automatic sampling prior to entering the receiving waters through
diffusers.
The sludge is dewatered by vacuum filter and sludge press and sanitary
landfilled for kraft and kraft-NSSC mills, while the sludge is
dewatered by vacuum filters and sanitary landfilled for NSSC mills and
for paperboard from waste paper mills (or reused back into the process).
The screenings are burned in bark burners in case of kraft mills,
kraft-NSSC mills, and the NSSC mills. The screenings are sanitary
landfilled in case of paperboard from waste paper mills.
BATEA
All mill effluents are screened by bar screens, and are subjected to
primary solids separation in mechanical clarifiers and secondary
treatment by nutrient addition and two stage biological treatment. All
mill effluents have mixed-media filtration with, if necessary, chemical
addition and coagulation. Unbleached kraft and kraft-NSSC (cross
recovery) mills have color removal by lime treatment. NSSC-sodium base
and NSSC-ammonia base mills have color removal by reverse osmosis.
All mill effluents receive foam control treatment, monitoring and
automatic sampling prior to entering the receiving waters through
diffusers.
Screenings from the kraft mill and the kraft - NSSC mill effluents are
burned in sludge incinerators, and screenings from the NSSC - Sodium and
NSSC - Ammonia base mills are burned in existing bark boilers.
191
-------
Table 51 (Cont'd)
Primary sludges and waste activated sludge are thickened in gravity
sludge thickeners, and dewatered mechanically by vacuum filters and
presses prior to ultimate disposal.
Ultimate sludge disposal for kraft mills and kraft-NSSC mills is by
incineration, and for other subcategories by sanitary landfilling.
NSPS
All mill effluents are screened, receive primary solids separation in
mechanical clarifiers, and secondary treatment by nutrient addition, and
two stage biological treatment.
Unbleached kraft and kraft - NSSC (cross recovery) mills have color
removal by lime treatment. All effluents receive foam control,
monitoring and automatic sampling prior to entering the receiving water
through diffusers.
Screenings from the kraft mill, the kraft-NSSC mill, the NSSC - Sodium
and NSSC - Ammonia mills are burned in existing bark burners. The
screenings from paperboard from waste paper mills are disposed of by
sanitary landfilling.
Primary sludge and wasted activated sludge are thickened in gravity
thickeners prior to mechanical dewatering by vacuum filters and presses.
Sludges from unbleached kraft mills and Kraft-NSSC mills are
incinerated, while all other sludges are disposed of by sanitary
landfilling.
192
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Table 52
Effluent Treatment Cost and Effluent Quality
for 907 mtpd (1000 tpd) Unbleached Kraft (linerboard Mill)
a.
b.
c.
d.
TSS
BOD5
Color
I
0.
0.
0.
kg/kkg
35
25
-
None
E
0.
0.
0.
(Pounds
(70)
(50)
kiloliters/kkg
T I
0. 2160
394
0. 324
0. 70
Per Ton)
3
12
Pre
E
1820
' ' 480
254
226
(6)
(24)
-
T
3980
874
578
296
BPCTCA
I E
5397 4873
1542 1133
810 630
732 503
6.0 (12.0)
2.8 ( 5.6)
-
T I
10270 6197
2675 1739
1440 1079
1235 660
1
1
10
BATEA
E
8536
2437
1277
1160
.85 (3.7)
.35 (2.7)
(20)
T
14733
4176
2356
1820
NSPS
I E
NA 10652
NA 2892
NA 1588
NA 1304
3.75 (7.5)
1.55 (3.1)
10 (20)
T
10327
2751
1570
1181
(1000 gal/ ton)
104 (25) 50 (12)
Data are in $1000"s unless otherwise indicated.
I = Costs for Internal controls
E = Costs for External controls
T = Sum of costs I and E
46 (11) 37.5 (9) 37.5 (9)
a = Investment cost
b = Total annual cost (sum of c and d)
c = Interest cost plus Depreciation cost
at 15% per year.
d = Operating and Maintenance cost (including
energy and power) per year.
-------
Table 53
Effluent Treatment Cost and Quality
for 227 mtpd (250 tpd) NSSC - NA Mill
None
I
a 0.
b 0.
c 0.
d 0.
kg/kkg
TSS
BODS
Color
E
0.
0.
0.
0.
T
0.
0.
0.
0.
I
1785
744
268
476
Pre
E
602
171
81
90
T I
2387 2350
915 869
349 352
566 517
BPCTCA
E T I
1138 3488 2670
325 1194 964
145 497 401
180 697 563
BATEA
E
2038
409
306
103
T
4708
1372
706
666
(Ibs/ton)
37
175
kiloliters/kkg
.5
(75)
(350)
20 (40)
45 (90)
5.5 (11)
4.35 (8.7)
2
2
75%
.5 (5.0)
.25(4.5)
Removal
(1000 gal/ton)
NSPS
NA
NA
NA
NA
1592
413
239
174
1457
356
219
137
3.85 (7.7)
2.6 (5.2)
62.5 (15)
50 (12)
41.7 (10)
20.8(5)
20.8(5)
-------
Table 54
Effluent Treatment Cost and Quality
for 227 mtpd (250 tpd) NSSC NH3 Mill
None
I E T I
a - -
b - -
c - -
d -
kg/kkg (Ibs/ton)
TSS
BODS
Color
Pre
E T I
- - 0
0
0
- - 0
5
4
BPCTCA
E
1406
375
184
191
do)
(8)
T
1406
375
184
191
I
221
95
49
46
2.6 (5
3.2 (6
BATEA
E
1975
561
280
281
.2)
.4)
T
2196
656
329
327
75% removal
NA
NA
NA
NA
E
1954
528
284
244
i792
430
260
171
3.75 (7.5)
3.75 (7.5)
kiloliters/kkg (1000 gal/ton)
VO
171
33
(8)
25 (6)
25 (6)
-------
Table 55
Effluent Treatment Cost and Effluent Quality
for 907 mtpd (1000 tpd) Kraft - NSSC Mill
I
a 0.
b 0.
c 0.
d 0.
TSS
BODS
Color
None
E
0.
0.
0.
0.
kg/kkg
T
I
0. 2501
0.
0.
0.
440
360
80
Pre
E
T I
1460 3961 5229
400
190
210
880 1888
550 1193
290 695
BPCTCA
E T I
3668 8897 6269
934 2822 2067
504 1697 1432
430 1125 635
BATEA
E
8232
2401
1263
1138
T
14501
4468
2695
1773
(Ibs/ton)
35 (70)
30 (60)
—
kiloliters/kkg
(1000
3.5
24.5
gal/ton)
(7)
(49)
—
6.25 '12. 5)
4.0 (8.0)
—
2.1
1.6
12,5
(4.2)
(3.2)
(2:)
NSPS
I
NA
NA
NA
NA
E
9864
2848
1514
1334
4.0
2.9
12.5
T
9580
2705
1471
1234
(8.0)
(3.8)
(25)
92 (22) 75 (18)
54 (13)
33 (8)
33 (8)
-------
VD
•-J
Table 56
Effluent Treatment Cost and Quality
for 91 mtpd (100 tpd) Paperboard from Waste Paper
None
I
a 0.
b 0.
c 0.
d 0.
kg/kkg
TSS
BODS
E
0.
0.
0.
0.
T
0.
0.
0.
0.
I
105
29
15
14
Pre
E
314
76
42
34
T I
419 422
105 104
57 63
48 41
BPCTCA
E T I
561 983 422
155 259 104
74 137 63
81 122 41
BATEA
E T I
801 1223 NA
190 294 NA
115 173 NA
75 116 NA
NSPS
E
415
103
57
46
T
314
76
42
34
(Ibs/ton)
40 (80)
35 (70)
kiloliters/kkg (1000
4 (8)
15 (30)
2.5 (5.0)
1.5 (3.0)
0.8 (1.6)
0.65 (13)
2.0
0.75
(4.0)
(1.5)
gal/ton)
50 (12)
25 (6)
12.5 (3)
8.3 (2)
8.3 (2)
Note: In going from *) to **) practical considerations dictate that the internal
investment be made at BPCTCA. Therefore although a decrease in internal water
use is expected between BPCTCA and BATEA, the total required investment is given
in BPCTCA.
-------
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
following:
External treatment
power cost = 1.10/KWH
fuel price = $0.2t/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 57 as annual expenditures.
Estimated energy requirements for application of BPCTCA, BATEA, and NSPS
are shown in Table 58.
198
-------
Type of Mill
TABLE 57
POWER COSTS, $1000
Technology Level
Unbleached Kraft
907 kkg/day (1000 tons/day)
NSSC-Sodium Base
227 kkg/day (250 tons/day)
NSSC-Ammonia Base
227 kkg/day (250 tons/day)
Kraft-NSSC
907 kkg/day (1000 tons/day)
Paperboard from Waste paper
91 kkg/day (100 tons/day)
BPCTCA
2H8
121
73
232
BATEA
<*99
1U7
88(1)
503
H2
NSPS (2)
609
65
91(1)
509
27
(1) Costs for removal of nitrogen are not included because of lack of
sufficient data.
(2) Costs for NSPS treatment and control technology do not include
expenditures necessary for internal mill improvements. Sufficient
data were not available to establish this portion of the costs.
199
-------
INS
O
CD
Unbleached Kraft
907 kkg/day (1000 tons/day)
NSSC-Sodium Base
227 kkg/day (250 tons/day)
NSSC-Ammonia Base
227 kkg/day (250 tons/day)
Kraft-NSSC
907 kkg/day (1000 tons/day)
Paperboard
91 kkg/day (100 tons/day)
TABLE 58
ENERGY REQUIREMENTS
BPCTCA
kwh (kwh)
kkg
54
108
106
70
120
(ton)
(60)
(119)
(117)
(77)
(132)
BATEA
kwh (kwh)
kkg
106
135
190
122
217
(ton)
(117)
(149)
(210)
(135)
(239)
NSPS
kwh (kwh)
kkg
91
116
161
113
211
(ton)
(100)
(127)
(178)
(125)
(233)
-------
NON-WATER QUALITY ASPECTS OF CONTROL AND TREATMENT TECHNOLOGIES
Air Pollution Potential
There are several potential air pollution problems associated with the
external treatment of effluents from mills in each of the subcategories.
When properly designed and operated, primary and biological treatment do
not produce odors associated with anaerobic decomposition. However,
biological treatment of unbleached kraft and NSSC waste waters does
result in very localized odors, especially when mechanical aeration is
employed. The odor is characterized as wood extractives.
There are 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 objectionable under
low-^wind conditions close to the treatment site. Secondly, 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 improper 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 inhibits such decomposition, thus reducing odors.
The use of sanitary landfill practices will also mitigate odor problems.
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
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
201
-------
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" (113) .
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 reduction 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 preyent.
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.
202
-------
Sg^id 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:
UNBLEACHED KRAFT MILLS
(and Kraft-NSSC)
Bark
Rejects and Screenings
Grits and Dregs
Log wash Water
Ash
Waste Paper
Garbage
Trash
NSSC MILLS
Bark
Rejects and Screenings
Chemical Ash
Ash
Waste Paper
Garbage
Trash
PAPERBOARD FROM WASTE PAPER 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 by-product 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 usable
land. Grits and dregs from the causticizing system of the recovery
plant are inorganic solids which are generally water carried to a land
203
-------
disposal site. This is facilitated by their small quantity which
amounts to about 22.5 kg/kkg (45 Ibs/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. Wet 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 paperboard from waste paper mills, trash, such as rags, wire and
other metals, glass, and plastics, is removed in the breaker beater and
stock cleaning operations. This material, and grit from the rifflers,
is 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 EPA1s Office of Solid
Waste Management Programs (EPA Contract No. 68-03-0207).
204
-------
By-product Recovery
The unbleached kraft process is the only subject subcategory in which
significant quantities of by-products are recovered. The two major
saleable by-products 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 (114) and cooking variables. A
1969 study (115) reported yields ranging from 6.3-17.9 liters/kkg (1.5-
4.3 gal/ton) of pulp; its market value was estimated at 18£-36£/kkg
(200-402/short ton) ; and its recovery was calculated to represent
approximately one percent diminution 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 in the manufacture 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 (13).
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 (115).
Tall oil yield per metric ton of kraft peaked in 1968 at about 47.5
kg/kkg (95 Ibs/ton) and has declined to about 34 kg/kkg (78 Ibs/ton) in
1973. (116). Normal variations occur depending on the fatty content of
the wood, skimmer efficiency, and other factors. Efficiency of recovery
now averages about 75-80 percent (117).
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 kkg ($80 per ton), a 25 percent increase over
the past five years (116). The economic incentive for increased soap
recovery 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
necessity for more frequent boil-out during which liquor losses inevita-
bly occur. Frequent skimming of the weak liquor storage tanks is needed
205
-------
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
(117).
Mill practices which will permit more complete recovery of turpentine
and tall oil are forecast. For example, shorter storage of chips or
precooking 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.
On the other hand there are factors which will inhibit recovery of these
by-products. 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 (117). Use of more hardwood,
sawmill wastes, immature wood, and outside chip storage are other
adverse factors (116).
Production of other by-products, 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 by-product recovery in the next decade.
206
-------
IMPLEMENTATION REQUIREMENTS
Availability of Equipment
v
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 32 shows 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 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, replacement of existing facilities, and the construction
of advanced waste treatment facilities.
Figure 33 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
follows the trend shown in Figure 32.
The data in Figures 32 and 33 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
207
-------
L
208
-------
602
MILLIONS OF DOLLARS
J
81
-------
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
distribution of waste water treatment equipment to industry. In various
areas, certain suppliers may be more successful than others; however,
this seems to be related more to the effectiveness of the sales
activities than to as geographical limitations. The use of independent
metal fabricators as subcontractors to manufacture certain pieces of
equipment further reduces geographical limitations.
Equipment delivery schedules may vary substantially depending upon the
manufacturer, the current demand, and the specific equipment in
question. Obviously, the 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 although there is still some concern about localized problems
(118). 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 6U4. 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.U percent over an 11 year period of
approximately five percent per year.
210
-------
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.U 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 first three months of 1973
saw some escalation of costs due to allowable materials price gains
(106). 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. This is shown in Figure 34.
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 18.9 MLD (5 MGD) ,
18.9 - 37.8 MLD (5-10 MGD), and over 37.8 MLD (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 36 that it
should be possible in all cases to meet the implementation requirements
of the July 1977 deadlines.
211
-------
ZIZ
CONSTRUCTION COST INDEX
OZ
ZF>
21 z
z M
^^^
OF u>
-------
in
U)
tt
U
4
UJ
IOOO
500
100
50
NATURAL
STAB 1LIZ AT»ON
AERATED
STABILIZATION!
PRIMARY
ACTIVATED SLUDG»E.
213
FIGURE 35
LAND REQUIRED FOR
'WASTEWATER. TREATMENT
-------
SIZE
IViGD
UNDER 5
COMV.
UMSER 5
TURNKEY
5-10
COMV
5-10
turner
OVER IO
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OVER IO
TURNKEY
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M J J A
PRELIMtMARY ENGINEERING
FIMAL DESIGN ENGINE.ERIMG FIGURE •*&
BID AND CONSTRUCTION AWARD
TlN^B t?EQU\RtD TO
CONSTRUCTION COMSTRUCT WASTtWA-TtR F^C\LtT\E^
COKIVEMTIOKJAU < TURK1KEY COK1TCIAC.TS
-------
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 was also be given to:
a. the total cost of application of technology in relation to the
effluent reduction benefits to be achieved from such application;
b. the size and age of equipment and facilities involved;
c. the process 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 a subcategory.
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.
215
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- ATTAINABLE THROUGH THE APPLICATION OF BEST
PRACTICABLE CONTROL TECHNOLOGY CURRENTLY AVAILABLE
Based upon the information contained in Sections III through VIII and in
the Appendices in this report, a determination has been made that the
point source discharge limitations for each identified pollutant, as
shown in Table 59, can be obtained through the application of the best
practicable pollution control technology currently available.
Table 59
BPCTCA Effluent Limitations
Values in kg/kkg (1bs/ton)
Subcateqory
Unbleached Kraft
NSSC-Ammonia
NSSC-Sodium
Unbleached
Kraft-NSSC
Paperboard from
Waste Paper
BOD5
30 Day Daily Max
2.8 (5.6) 5.6 (11.2)
4.0 (8.0) 8.0 (16.0)
4.35(8.7) 8.7 (17.4)
TSS
30 Day Daily Max
6.0 (12.0) 12.0 (24.0)
5.0 (10.0) 10.0 (20.0)
5.5 (11.0) 11.0 (22.0)
4.0 (8.0) 8.0 (16.0) 6.25(12.5) 12.5 (25.0)
1.5 (3.0) 3.0 (6.0) 2.5 (5.0) 5.0 (10.0)
pH for all subcategories shall be within the range of 6.0 to 9.0
The maximum average of daily values for any thirty consecutive day
period should not exceed the 30 day effluent limitations shown above.
The maximum for any one day should not exceed the daily maximum effluent
limitations as shown above. The limitations shown above are in
kilograms of pollutant per metric ton of production (pounds of pollutant
per short ton of production). Production is defined as the annual
average level of production off the machine (air dry tons). Effluents
should always be within the pH range of 6.0 to 9.0.
The TSS parameter is measued by the technique utilizing glass fiber
filter disks as specified in Standard Methods for the Examination of
Water and Wastewater (13th Edition) (1).
216
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IDENTIFICATION OF BE.ST PRACTICABLE CONTROL TECHNOLOGY
AVAILABLE
Best practicable control technology currently available is the same for
all subject subcategories with regard to external treatment of indus-
trial wastes. However, applicable technology in normal use varies
between subcategories for internal control measures. The internal
controls identified are in common use among the subcategories.
Approximately 60-100* of mills within the subcategories studied use some
or all of the identified internal controls. The following is a
discussion of both these internal and external controls. It should be
emphasized that it is not expected that all of the internal controls
listed are needed for mills to meet the limitations. Also, the internal
controls, as well as the external controls, are identifications (not
requirements) of pollution control technologies which can be utilized to
meet the BPCTCA limitations. In addition, mills have the option for
pollutant reduction by well designed and operated external treatment
systems or by a combination of both internal and external controls which
may prove to be more cost effective.
Internal Control
Unbleached Kraft
a. Hot Stock Screening
As explained in Section VII, this is a process modification in which
the pulp is passed through a fibrolizer 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. This should be accomplished without
increasing black liquor concentrations in the white water system.
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. Also,
storage facilities can be supplied to contain weak black liquor,
strong black liquor, and recovery plant chemicals and liquors from
process upsets for ultimate return to the system or for gradual
discharge to the waste water treatment system such that no treatment
upset occurs.
c. Efficient Pulp Washing
The efficient recovery of black liquor is predicated upon efficient
pulp washing which can be accomplished by multi-stage countercurrent
washers. Multi-stage countercurrent washers minimize water usage
and result in efficient liquor recoveries.
217
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NSSC - Sodium Base
a. Non-Polluting Spent Liquor Disposal
Spent liquor disposal can be accomplished by partial evaporation
followed by incineration in a fluidized bed reactor or other com-
parable unit. Efficient liquor disposal is predicated upon good
pulp washing efficiencies.
NSSC - Ammonia Base
a. Non-Polluting Spent Liquor Disposal
Spent liquor disposal can be accomplished by partial evaporation
followed by incineration. Efficient liquor disposal is predicated
upon good pulp washing efficiencies.
Kraft - NSSC (cross recovery)
a. Hot Stock Screening
As explained in Section VII, this is a process modification in which
the pulp is passed through a fibrolizer 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. This should be accomplished without
increasing black liquor concentrations in the white water system.
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. Also,
storage facilities can also be supplied to contain weak black
liquor, strong black liquor, and recovery plant chemicals and
liquors from process upsets for ultimate return to the system or for
gradual discharge to the waste water treatment system such that no
treatment upset occurs.
c. Efficient Pulp Washing
The efficient recovery of black liquor is predicated upon efficient
pulp washing which can be accomplished by multi-stage countercurrent
washers. Multi-stage countercurrent washers minimize water usage
and result in efficient liquor recoveries.
218
-------
Paperboard from Waste^Paper
a. Land Disposal of Junk Materials
Extraneous matter found in waste paper, such as metals, plastics,
and rags, can be efficiently removed from the process and disposed
of in approved landfills.
All Subcateqories (Paper Machines)
a. Water Showers
Fresh water showers used to clean wire, felt, and other machine
elements (of both fourdrinier and cylinder machines) can be low-
volume and high-pressure; white water showers can be low pressure,
high-volume, and self-cleaning.
b. Segregation of White Water Systems
The segregation of white water systems can be designed to permit
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 can be employed to remove felt
hairs prior to press water reuse.
d. Collection System for Vacuum Pulp Seal Water
Seal water can be collected for partial reuse and/or cascade to or
from other water users.
e. Save-all with Associated Equipment
An effective save-all can 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, can be exercised.
219
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External Treatment
a. Suspended Solids Reduction
This step involves removal of suspended solids from the raw waste
stream. It can incorporate 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.
b. BOD5 Reduction
The treatment system for reduction of BOD5 is biological oxidation with
nutrient addition. The treatment system can consist of the activated
sludge process (AS), aerated stabilization basins (ASB), and/or storage
oxidation ponds (SO).
c. Biological Solids Removal
The treatment system should provide for removal of biological solids by
either mechanical clarifiers, stilling ponds (or a SO following an ASB),
or a quiescent zone in an ASB which is beyond the influence of the
aeration equipment.
d. Sludge Disposal
When compatible with other unit processes, sludge disposal can often be
carried out in a stilling pond. However, this necessitates periodic
dredging, removal, and disposal of solids. Where activated sludge and
mechanical clarification are utilized, sludge handling can be
accomplished through sludge thickening followed by sludge dewatering and
by vacuum filtration or centrifugation, and ultimate solids disposal.
Disposal can be accomplished by either sanitary landfilling or
incineration. Combustion can be carried either in a sludge incinerator,
the power boiler, or the bark boiler in unbleached kraft pulp mill
operations.
220
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RATIONALE FOR THE SELECTION OF BEST PRACTICABLE POLLUTION CONTROL
TECHNOLOGY CURRENTLY 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
duplicated as mill size expands. Consequently, there is no significant
variation in either the waste water characteristics or in the waste
water loading rates between mills of varying sizes.
Process Change
Application of the best practicable control technology currently
available does not require major changes in existing industrial
processes for the subcategories studied. The identified in-plant
systems representing BPCTCA have previously been installed at most mills
and are thus in common use. Incorporation of any 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.
The in-plant technology to achieve these effluent limitations is
practiced and generally in common use within the subcategories under
study. The concepts are proven, available for implementation, and
applicable to the wastes in question. The waste treatment techniques
are also broadly applied within many other industries. The technology
identified 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 in operation and maintenance of waste
treatment facilities. However, these procedures are commonly practiced
in pulp and paper 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 unless
sanitary landfilling techniques are properly instituted.
221
-------
The technology cited will not create any significant increase in noise
levels beyond those observed in well designed municipal wastewater
treatment systems which currently are being approved by the Federal
government for construction in populated areas. Further, no hazardous
chemicals are required as part of this technology.
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 (less than one per cent) and should not be great enough to
warrant concern on either a national or regional basis.
t of Application in gelation to Effluent Reduction Benefits
Based upon the information contained in Section VIII and the Appendices
of this report, the total projected costs of BPCTCA reflect an increase
of production expenses as shown in Table 60.
Table 60
Cost of Application of BPCTCA (1971 Cost Index)
Production Total Annual Increase in Costs
kkg/day Cost, Incl. $/kkg
Subcategorv _ (tons/day) ____ ___ Ener3y_ _ ($/ton) ________
Unbleached Kraft 907 (1CCO) $2,675,000 8. 43 (7.65)
NSSC-Sodium Base 227 (250) $1,194,000 15.04 (13.65)
NSSC-Ammonia Base 227 (250) $375,000* 4.74 (4.30)*
Kraft-NSSC
(Cross Recovery) 907 (1000) $2,922,COC 8.60 (7.80)
Paperboard from
Waste Paper 91 (100) $259,000 9.53 (8.64)
*Cost data for internal mill improvements was not available.
Thus, these costs reflect only the external treatment identified.
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 paperboard from waste paper subcategory which is based upon 30C
days/year. It should be emphasized, however, that most mills have
already carried out many of these improvements. Consequently, their
increased costs would be less than those shown above.
222
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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.
RATIONALE FOR SELECTION OF EFFLUENT LIMITATIONS
The determination of the BPCTCA limitations shown in Table 59 were made
through the consideration of all available data for the subcategories
under study. On consideration of the data contained in Sections III, V,
VII, VIII, and in the Appendices of this report, specific mills were
selected as "best performers" based upon effluent qualities being
achieved by the mills within the subcategories. The mills were selected
to be representative of mills within the specific subcategory, and this
included an analysis of pollution control technologies utilized by each
mill as being practicable for all mills within each subcategory.
The 30 day limitations were essentially determined by using the average
of the best performers maximum month of pollutant discharged, as this
accounts for variations in the final effluent qualities as affected by
such factors as raw waste or extreme climatic conditions. The daily
maximum limitations were determined by doubling the 30 day limitations.
The factor of two resulted from an analysis of data relating daily
maximum to maximum month.
Unbleached Kraft
Tables 61 and 62 show mills selected as best performers for the
unbleached kraft subcategory. The mills were selected as representative
of BPCTCA and included are six of seven unbleached kraft mills achieving
the best final effluent qualities in the country. The mill achieving
the best final effluent quality in this subcategory was mill UK-3, but
the mill's external treatment system was judged to be atypical of the
subcategory and was thereby not included as a best performer. The
treatment system included an ASB followed by a storage oxidation pond
with a detention time in excess of 240 days. Storage oxidation ponds
are utilized at nearly 50% of unbleached kraft mills and common sizes
range up to 60 days detention time. The large land area utilized by
mill UK-3 for its storage oxidation pond was judged to be atypical, as
the large land areas may not be available at all unbleached kraft mill
sites. In addition, it was determined that the BPCTCA included both
stages of treatment at the mills utilizing ASBs followed by storage
oxidation ponds as discussed in Section VII. Therefore, because of the
large land areas necessary for the storage oxidation ponds, the effluent
limitations were determined so that a mill with a well designed and
operated ASB should be able to achieve effluent qualities comparable to
the ASB-storage oxidation pond system.
223
-------
TABLE 61
ro
ro
Mill
UK-1
UK-2
UK-5
UK-6
UK-7
UK-8
Ave.
Production-AA
kkg/day
(tons/day)
1020(1125)
825(909)
1201(1324)
732(807)
641(707)
997(1099)
BEST PERFORMERS
MILL DATA
UNBLEACHED KRAFT
Flow-AA
kiloliters/kkg
(1000 gal/ton)
39.2(9.4)
50(12.0)
60(14.4)
64.2(15.4)
112.6(27.0)
43.7(10.4)
51.40-2.3)*
Treatment
Detention Times (Days)
ASB SO
7.5
18
10
10
7.6
0
0
51
0
8
7
60
Aeration
in HP
ASB
375
480
1500
1050
1100
*not including UK-7
-------
TABLE 62
BEST PERFORMERS
MILL EFFLUENT DATA
UNBLEACHED KRAFT
(AH values in kg/kkg (Ibs/ton) except as noted)
Raw Waste
Final Effluent
ro
in
Mill
UK-1
UK- 2
UK-5
UK-6
UK- 7
UK- 8
AA
BODS
13.5(27)
12.2(24.5)
19(38)
21.2(42.5)
-
19(38)
AA
TSS
10.5(21)**
-
19.5(39)
- -
-
-.
AA
BOD5
1.4(2.8)
0.8(1.6)
2.1(4.3)
2.2(4.5)
2.1(4.2)
2.3(4.7)
MM
BODS
2.3(4.6)
1.3(2.7)
3.1(6.1)
3.7(7.4)
3.1(6.2)
3.3(6.6)
MM
BODS*
50
25
55
43
27
75
4
2
5
2
3
2
AA
TSS
.7(9.4)
.2(4.5)
.1(11.2)
.5(5.0)
.6(7.2)
.9(5.9)
6
3
7
3
4
3
MM
TSS
.1(12.1)
.8(7.6)
.1(14.2)
.9(7.9)
.6(9.3)
.5(7.0)
MM
TSS*
119
69
124
46
34
69
Average
* mg/1
**NSM
17(34.0)
21.5(43)
1.8(3.7)
2.8(5.6)
46
3.6(7.2) 4.8(9.7)
77
-------
The BODJ5 limitations for unbleached kraft mills were determined by
averaging the maximum month of pollutant discharge for the mills shown
in Tables 61 and 62. However, the TSS limitations were based on mill
UK-1 and not on an average of the best performers' TSS levels. As
discussed above, mills using storage oxidation ponds use large land
areas not always available at all unbleached kraft mills and since
storage oxidation ponds reduce TSS levels below the levels achieved by
ASBs, the limitations were based on mill UK-1.
As shown in Table 61, the average flow rate for the best performers was
61,720 liters/kkg (14,800 gal/ton) with a more representative average of
51,290 liters/kkg (12,300 gal/ton) excluding the mill UK-7 flow rate
which disproportionately affects the average. The average flow rate for
unbleached kraft mills as presented in Table 22 was 52,540 liters/kkg
(12,600 gal/ton). Thus, the average of the best performers was very
close to the average for all mills in the subcategory. Another source
stated the average for the subcategory was 41,700 liters/kkg (10,000
gal/ton) (40) which indicates that the average of the best performers'
flow rates was 8,340 liters/kkg (2,000 gal/ton) greater than the average
for the subcategory. This may indicate that the mills selected as best
performers had less than the average extent of in-plant controls. In
addition, the average raw waste BOD.5 for the best performers was 17.0
kg/kkg (34 Ibs/ton) which is very near the average for the subcategory
of 16.9 kg/kkg (33.8 gal/ton). Since the flow rate and the raw waste
BOD5 indicate the extent of internal controls applied within mills, the
above discussion indicates that the extent of internal controls at the
best performers is very near the average for the entire subcategory.
NSSC-Ammonia Base
Mill N-1 in Tables 44 and 45 which is the one mill which had biological
treatment of the two in the subcategory was not selected as
representative of BPCTCA. Analysis of the final effluent data as well
as data from primary and ASB effluents and analysis of some of the
treatment system design paramters showed that the treatment system
appeared to be underaerated to adequately reduce the raw waste load. In
addition, several operating problems in the treatment system were
apparent, such as high levels of TSS (300-400 mg/1) in the ASB influent
from the clarifier.
The BOD5 limitations were determined by using the maximum month BOD5
concentration of 100 mg/1 for mill NS-2 of the NSSC-sodium base
subcategory and the maximum month flow rate for mill N-1. The TSS
limitations were determined using the maximum month flow rate for mill
N-1 and a TSS concentration of 120 mg/1 which has been shown to be
achievable by ASB treatment systems in the unbleached kraft and
unbleached kraft-NSSC (cross recovery) subcategories.
226
-------
NSSC-Sodium Base
Tables 63 and 64 shows the mill selected as the best performer for the
NSSC-sodium base subcategory. Mill NS-1 was not included as a best
performer because the mill was considered to be an atypical mill. Mill
NS-1 spray irrigates the spent cooking liquor whereas the more common
practice includes evaporation and incineration of the waste liquor which
adds significantly to the raw waste load. Also, mill NS-1 uses waste
paper for approximately one third of the furnish whereas mill NS-2 uses
about 6%. This can also have some effect on the raw waste load.
The BOD5 limitations were based upon the maximum month of BOD5 discharge
from mill NS-2. Mill NS-2 has been experiencing difficulties with
sludge bulking from their clarifiers as the maximum month TSS discharge
was 18.75 kg/kkg (37.5 Ibs/ton) or 428 mg/1. Thus, the TSS limitations
were not entirely based on mill NS-2 but was determined by using the
maximum monthly flow rate for NS-2 and a TSS concentration of 120 mg/1.
The concentration value was demonstrated by ASB treatment systems in the
unbleached kraft and unbleached kraft-NSSC (cross recovery)
subcategories.
As shown in Table 22, the average flow rate and raw waste BOD5 load for
sodium base NSSC mills was 42,950 liters/kkg (10,300 gal/tonT and 25.15
kg/kkg (50.3 Ibs/ton), respectively. The flow rate and raw waste BOD5_
load for the best performer, NS-2, are 48,790 liters/kkg (11,700
gal/ton) and 31 kg/kkg (62 Ibs/ton), respectively. This indicates that
excessive internal controls are not needed for all mills to meet the
limitations as demonstrated by mill NS-2. Mill NS-2 reduced their
higher than average raw waste load to acceptable BPCTCA levels through
external treatment.
Unbleached Kraft-NSSC (Cross Recovery^
Tables 65 and 66 shows mills selected as best performers for the
unbleached kraft-NSSC (cross recovery) subcategory. Mill X-2 is not
included as the mill discharges a portion of its raw waste to gravel
beds for six to nine months per year and thus is an atypical treatment
system.
The BOD5. limitations for the unbleached kraft-NSSC (cross recovery)
subcategory were determined by averaging the maximum month of pollutant
discharged for the mills shown in Table 66. However, the TSS
limitations were based on mill X-1 which used an ASB. Mills X-3 and X-4
used two stage treatment systems of ASB-storage oxidation ponds. The
rationale for the methodology used in determining the TSS limitations
were discussed previously for unbleached kraft mills.
As shown in Tables 65 and 66, the average flow rate and raw waste BOD5.
loads for the best performers were 58,380 liters/kkg (14,000 gal/tonT
and 20.15 kg/kkg (40.3 Ibs/ton), respectively. The flow rate is equal
to the subcategory average and the BOD5. raw waste load is higher than
227
-------
Mill
NS-1
NS-2
* Clarifier-ASB-Clarifier
return sludge
Production-AA
kkg/day
(tons/day)
336(370)
521(574)
TABLE 63
BEST PERFORMERS
MILL DATA
NSSC - SODIUM BASE
Flow-AA
kiloliters/kkg
(1000 gal/ton)
44.6(10.7)
48.8(11.7)
Treatment
Detention (Days)
ASB SO
14
0
Aeration
in HP
ASB
515
1200
TSS
Methods
SM
SM
ro
CD
-------
TABLE 64
BEST PERFORMERS
MILL EFFLUENT DATA
NSSC - SODIUM BASE
Mill
NS-2
*mg/l
ro
ro
vo
(All values in kg/kkg (Ibs/ton) except as noted)
Raw Waste Final Effluent
AA AAAA MM MM AAMMMM
BODS TSS BODS BODS BODS* TSS TSS TSS*
31(62) 17.5(35) 3.2(6.4) 4.3(8.7) 97 13.3(26.6) 18.7(37.5) 424
«
-------
Mill
X-l
X-3
X-4
Production-AA
kkg/day
(tons/day)
1110(1224)
1824(2011)
1215(1340)
TABLE 65
BEST PERFORMERS
MILL DATA
UNBLEACHED KRAFT-NSSC (CROSS RECOVERY)
Flow-AA
kiloliters/kkg
(1000 gal/ton)
57.5(13.8)
43.4(10.4)
74.3(17.8)
Treatment
Detention Time
ASB
7.5
18
11
(Days)
SO
0
4
5
Aeration
in HP
ASB
900
1000
1060
TSS
Method
SM
SM
SM
Ave,
58.4(14.0)
-------
Ave.
TABLE 66
BEST PERFORMERS
MILL EFFLUENT DATA
UNBLEACHED KRAFT-NSSC (CROSS RECOVERY)
(All values in kg/kkg (Ibs/ton) except as noted)
Raw Waste Final Effluent
Mill
X-l
X-3
X-4
AA
BODS
24(48)
16.3(32.6)
AA
TSS
28.5(57)
13.4(24.9)
AA
BODS
2.7(5.5)
3.3(6.7)
2.7(5.5)
MM
BODS
3.5(7.1)
4.7(9.5)
3.9(7.8)
MM
BODS*
66
105
51
AA
TSS
5(10)
2.8(5.6)
2.9(5.7)
MM
TSS
6.4(12.8)
3.4(6.9)
5.1(10.3)
MM
TSS*
118
72
69
20.2(40.3)
20.5(41.0)
3.0(5.9) 4.1(8.1)
74
3.6(7.1) 5.0(10.0)
*mg/l
**Primary Treatment Effluent
86
-------
-------
the subcategory average of 19.4 kg/kkg (38.8 Ibs/ton). As described
previously, the above comparison of flow rates and raw waste BOD5 loads
indicates that the extent of internal controls at the best performers is
very near the average for the entire subcategory.
Paperboard from Waste Paper
Tables 67 and 68 present data from mills selected as best performers in
the paperboard from waste paper subcategory. The selected mills have
either activated sludge or aerated stabilization basin treatment
systems.
The BOD5 and TSS 30-day limitations were based upon the maximum month
BOD5 and TSS values for the mills in Table 68. The average BOD5 raw
waste load for the mills selected as best performers was 8.5 kg/kkg
(16.9 Ibs/ton) which is less than the subcategory average of
approximately 11.25 kg/kkg (22.5 Ibs/ton). Thus, the limitations were
adjusted to reflect the higher waste load.
The data presented in Tables 18 and 49 indicates that raw waste BOD5
from paperboard from waste paper mills can be efficiently removed by
either activated sludge or aerated stabilization basins treatment
systems. The percentage removals for the mills selected as best
performers (NOTE - all paperboard from waste paper mills with secondary
treatment and available data are included as best performers) average
93% with a range of 85-97.5X. Thus, even though the average BOD5 raw
waste load was higher for the subcategory than that for the best
performers, the mills with higher than average raw waste loads should be
able to meet the limitations through demonstrated efficient treatment.
All Subeateqories: pH Range
The pH range of 6.0-9.0 in receiving waters is satisfactory for aquatic
life as specified in the draft document by the National Academy of
Sciences (NAS) on Water Quality Criteria. Thus, the effluent
limitations of pH range 6.0-9.0 were chosen for all subcategories.
233
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TABLE 67
BEST PERFORMERS
MILL DATA
PAPERBOARD FROM WASTE PAPER
Mill
P-15
^P-16
«S»P-17
P-18
P-19
P-20
P-21
P-22
Ave.
Production-AA
kkg/day
(tons/day)
145(160)
272(300)
440(485)
245(270)
56(62)
91(100)
145(160)
91(100)
Flow-AA
kiloliters/kkg
(1000 gal/ton)
68.4(16.4)
12. 1( 2.9)
19. 6( 4.7)
38. 8( 9.3)
5.0( 1.2)
47.5(11.4)
9.5( 2.3)
38. 8( 9.3)
30. Q( 7.2)
Treatment
C-ASB
C-ASB-C
ASB-SO
C-AS-C
C-AS-C
C-ASB-HP
C-ASB
ASB-DAF
Aeration
in HP
100
300
120
40
120
60
TSS
Method
NSM
SM
SM
SM
SM
SM
SM
SM
-------
TABLE 68
BEST PERFORMERS
MILL EFFLUENT DATA
PAPERBOARD FROM WASTE PAPER
ro
o>
in
Mill
P-15
P-16
P-17
P-18
P-19
P-20
P-21
P-22
AA
BODS
16.2(32.5)
10(20)
6(12)
5.5(11)**
4(8)
7.5(15)
9.5(19)
9(18)
Raw Waste
AA
TSS
72.5(145)
9(18)
-
35(70)**
4.7(9.5)
6.5(13)
2.8(5.6)
7.5(15)
.ues kg/kkg (Ib/ton) except as noted)
AA
BODS
1.6(3.3)
0.25(0.5)
0.55(1.1)
0.15(0.3)
0.1(0.2)
1.1(2.2)
0.3(0.6)
1.0(2.0)
MM
BODS
2.4(4.9)
0.7(1.4)
1.6(3.2)
0.35(0.7)
0.15(0.3)
1.9(3.8)
0.7(1.4)
1.2(2.4)
MM
BODS*
52
58
82
09
17
42
74
31
Final Effluent
AA
TSS
6.3(12.7)
1.3(2.6)
0.8(1.6)
0.9(1.9)
1.0(2.0)
1.4(2.8)
0.55(1.1)
1.8(3.6)
MM
TSS
8.7(17.4)
3.6(7.3)
2.0(4.0)
1.5(3.1)
2.1(4.2)
2.7(5.4)
1.7(3.5)
2.9(5.9)
MM
TSS*
223
301
103
40
383
61
186
75
Aves. 8.5(16.9)
10.9(21.9)
*mg/l
** Primary Treatment Effluent
0.6(1.3)
1.1(2.3)
46
1.1(2.2) 2.4(4.8)
164
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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
determined by identifying the very best control and treatment technology
employed by a specific point source within a given subcategory, or by
applying technology from other industry areas where it is transferrable.
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
application of the technology;
f. non-water quality environmental impact, including energy
requirements.
This level of technology emphasizes both in-plant process improvements
and external treatment of waste waters. It will, therefore, require
existing mills to implement significant internal process changes for
water reuse and chemical recovery and recycle as well as to apply more
advanced waste treatment processes and other improved internal and
external controls in order to meet the effluent limitations. In some
cases, the industry may be required to conduct applied research and
demonstration studies in order to firmly establish the most economical
approach toward meeting the limitations. Such studies on the removal of
color and nitrogen, where applicable, will be undoubtedly desirable.
237
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EFFLUENT REDUCTION ATTAINABLE^THROUGH APPLICATION OF THE BEST AVAjLABLE
TECHNOLOGY ECONOMICALLY ACHIEVABLE ~ ~ ~
Based upon the information contained in Sections III through VIII and
the appendices of this report, a determination has been made that the
point source discharge limitations for each identified pollutant as
shown in Table 69 can be obtained through the application of best
available technology.
Table 69
BATEA Effluent Limitations v
Values in kg/kkg (Ibs/ton)
BODS
TSS
Subcateqory
Unbleached
Kraft
NSSC - Ammonia
NSSC - Sodium
Unbleached
Kraft - NSSC
Paperboard from
Waste Paper
30 Day
Daily Max
30Dav
DailvMax
1.35
3.2
2.25
1.6
0.65
(2.7)
(6.1)
(U.5)
(3.2)
(1.3)
2.7
6.U
4.5
3.2
1.3
(5.
(12.
(9.
(6.
(2.
<*)
8)
0)
4)
6)
1.
2.
2.
2.
0.
85
6
5
1
8
(3.
(5.
(5.
(4.
(1.
7)
2)
0)
2)
6)
3.7
5.2
5.0
a. 2
1.6
(7.
(10.
(10.
(8.
(3.
<»)
<*)
0)
<0
2)
Subcategorv
Unbleached
Kraft
NSSC •* Ammonia
NSSC - Sodium
Unbleached
Kraft - NSSC
Paperboard from
Waste Paper
Color
Daily._Max_
10 (20)
75% removal
75% removal
12.5 (25)
15
(30)
18.75(37,5)
pH for all subcategories shall be within the range of 6.0 to 9.0
238
-------
The maximum average of daily values for any 30 consecutive day period
should not exceed the 30 day effluent limitations shown above. The
maximum for any one day should not exceed the daily maximum effluent
limitations shown above. The limitations are in kilograms of pollutant
per metric ton of production (pounds of pollutant per short ton of
production). Effluents should always be within the pH range of 6.0-9.0.
Production is defined as the annual average production off the machine
(air dry tons) .
Effluent limitations are needed for nitrogen for NSSC ammonia base mills
only. However, no specific limitations have been established because of
the extreme lack of meaningful data. Currently, only two such mills
exist and preliminary indications are that discharges in the range of
7.5-10.0 kg/kkg (15-20 Ibs/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. Extensive studies on effective
methods for the removal of nitrogen in these concentrations must be
carried out before specific effluent limitations can be established.
The TSS parameter is measured by the technique utilizing glass fiber
filter disks as specified in Standard Methods for the Examination of
and Wastewater , (13th Edition) (1) .~
The color parameter is measued by the NCASI testing method as described
i-n NCASI Technical Bulletin $,253 (2) . The above color limitations of
75% removal for both sodium and ammonia base NSSC subcategories will be
changed to kilograms of color per metric ton of production (pounds of
color per short ton of production) at a later date when the technology
has been proven through further development. Color units are to be
assumed equal to mg/1 in determining kilograms (pounds) of color per
metric ton (short ton) of production.
239
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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
implement 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 without decreasing
washing efficiencies;
d. extensive internal reuse of process waters;
e. separation of cooling waters from other waste water streams, and
subsequent heat removal and reuse;
f. extensive 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.), the same modifications and procedures are applicable to and
capable of implementation by all paper machine systems, including
paperboard from waste paper mills.
240
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External Treatment
Section IX of the report describes best practicable external control
technology currently available. Application of that technology in
conjunction with several additional recognized and potential
technologies described in Section VII constitutes best available
technology economically achievable. The additional external processes
applicable to this more advanced technology are as follows:
a. BOD5 Reduction
The treatment system for reduction of BOD| is biological
oxidation with nutrient addition.
b. Suspended solids Reduction
In addition to the technologies i<3enl4fie4 in Sectj.cn IX,
suspended solids can be further jreduc
-------
RATIONALE FOR THE SELECTION OF THE BEST AVAILABLE TECHNOLOGY
ECONOMICALLY ACHIEVABLE
Age and Sige of Equipment and Facilities
There is a wide range, in both size and age, among mills in the
subcategories studied. However, internal operations of most older mills
have been upgraded, and some of these mills currently operate very
efficiently. The technology for updating of older mills is well
established, and does not vary significantly from mill to mill within a
given subcategory. Studies have also shown that waste treatment plant
performance 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 Ibs/ton
of product), between mills of varying sizes.
Process Changes
Application of the best available technology economically achievable may
require some major changes in existing industrial processes for the sub-
categories studied. Incorporation of additional systems, treatment
processes, and control measures can be accomplished through changes in
piping, through design modifications to existing equipment, and through
installation of additional equipment. Such alternations can be carried
out on all mills within a given subcategory.
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
transferable. However, sufficient research and pilot work has been
carried out on all parameters to demonstrate the feasibility of
achieving the limitations after completion of additional study. 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
dewatered sludges disposed of on land can present an odor problem unless
sanitary landfilling techniques are properly instituted.
The technology cited will not create any significant increase in noise
levels beyond those observed in well designed municipal wastewater
242
-------
treatment systems which currently are being approved by the Federal
government for construction in populated areas. Further, no hazardous
chemicals are required as part of this technology.
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 subcategories under study are not
substantial and should not be great enough to warrant concern on either
a national or regional basis.
Cost of Application in Relation to Effluent Reduction Benefits
Based upon the information contained in Section VIII and the Appendices
of this report, total projected cost of upgrading a mill incorporating
best practicable control technology currently available to the level of
best available technology economically achievable reflects an increase
in production expenses as shown in Table 70 (1971 price index).
Table 70
Cost af Application of BATEA
Production Total Annual Increase in Costs
kkg/day Cost Incl. $/kkg
Subcategory (tong/day^ ^ Energy _ i$/tgn)
Unbleached Kraft 907 (1000) $1,505,000 4.74 (4.30)
NSSC-Sodium Base 227 (250) $465,000 5.85 (5.31)
NSSC-Ammonia Base 227 (250) $383,000 4.83 (4.38)
Kraft-NSSC 907 (1000) $1,645,000 5.18 (4.70)
Paperboard from
Waste Paper 91 (100) $35,000 1.29 (1.17)
Th.ese increases reflect both all internal mill and external waste
treatment improvements, with the exception of nitrogen removal for NSSC
ammonia base mills. Sufficient data were not available on this
parameter. The increases are based on 350 days of production per year
except for the paperboard from waste paper subcategory which is based
upon 300 days per year.
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.
243
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RATIONALE FOR DEVELOPMENT OF BATEA EFFLUENT LIMITATIONS GUIDELINES
The rationale used in developing the BATEA effluent limitations for
BOD5, TSS, pH, and Color is discussed below.
The BOD5 BATEA limitations were determined by applying the estimated
BOD5 reductions for each applicable external control technology to the
projected BOD5. raw waste load for mills in 1983 as estimated by the
application of the identified internal controls. The estimated
efficiencies of BODjj removal for each external treatment technology
utilized in determining the BATEA limitations are shown below:
External Technology BOD5 Removal
Color Removal-minimum lime 15%
Biological Treatment 90%*
Coagulation 6 Filtration 15X
*95X used for Paperboard from Waste Paper Subcategory
The above percentage reductions were applied to the projected raw waste
loads (estimated by application of the internal controls described
previously) as applicable to each subcategory as shown in Table 71. It
should be noted that the BOD5 attributable to the application of reverse
osmosis for color removal was not estimated for NSSC mills in the
calculations. The above discussions describe the expected performances
on an annual basis. To determine the 30-day limitations, a ratio of
maximum month to annual average of 1.5 was applied. It is expected that
variations in final effluent qualities will be less than those
experienced by mills with BPCTCA of approximately 1.5 - 1.8 (maximum
month to annual average), as the BATEA should reduce the variations in
treatment efficiencies.
The TSS limitations were determined by using the BPCTCA limitations as a
base and applying the estimated TSS reductions as estimated by the
application of the BATEA. The calculations took into account the
relationship of TSS in the final effluent from biological treatment
systems and the BOD5 in the raw waste. Generally, the TSS levels are
directly affected by the BOD5 raw waste load, as the TSS in biological
treatment system effluents generally are biological organisms generated
in the removal of BOD5.. Also, the TSS limitations were based on the
application of the technology of coagulation and filtration which was
conservatively estimated to remove 60% of TSS from the biological
treatment effluent.
Analysis of the mill data showed that the common ratio of maximum day to
maximum month was approximately 2.0 for both BOD5. and TSS. Thus, the
daily maximum limitations were determined by applying 2.0 to the 30-day
limitations.
244
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TABLE 71
APPLICABLE EXTERNAL TECHNOLOGIES IN
DEVELOPMENT OF BATEA LIMITATIONS
Raw Waste
kg/kkg Color Biological
Subcategory (Ibs/ton) Removal Treatment
Unbleached 12.5(25) X X
Kraft
^ NSSC- 17.5(35) X
£ Sodium
NSSC- 25(50) X
Ammonia
Kraft- 15(30) X X
NSSC
Paperboard- 10(20) X
Waste Paper
-------
pH Range
The pH range of 6.0-9.0 in receiving waters is satisfactory for aquatic
life as specified in the draft document by the National Academy of
Sciences (NAS) on Water Quality ^Criteria. Thus, the effluent
limitations of pH range 6.0-9.0 were chosen for all subcategories.
Color
Unbleached Kraft
Minimum lime treatment systems have demonstrated that consistent
effluent levels of 125-150 CD can be attained independent of influent
color levels. Massive lime treatment systems have achieved effluent
levels of 200-250 CU. Using the BATEA and NSPS water usage of 37,560
liters/kkg (9,000 gal/ton) and demonstrated achievable color levels of
250 CU, the 30-day limitations were determined. The daily maximum was
determined by applying 1.5 to the 30-day limitations as the daily values
generally have been approximately SOX higher than the long term average.
Kraft - NSSC (Cross Recoyervl
The levels of color being achieved by minimum lime treatment systems
vary from near 100 CU to near 500 CU with the typical range between 300
to 380 CU. Based upon the projected effluent flow rate of 33,360
liters/kkg (8,000 gal/ton) and 380 CU, the effluent limitations were
determined. The daily maximum was determined by applying 1.5 to the 30-
day limitations as the daily values generally have been approximately
50% higher than the long term average.
NSSC - Ammonia Base, Sodium Base '
Reverse osmosis has not yet been demonstrated at full mill scale.
However, pilot scale studies have indicated that at least 75X reduction
of color should be achievable. Thus, the effluent limitations were
chosen as 75% removal of color.
246
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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.
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;
EFFLUENT REDUCTIONS ATTAINABLE THROUGH THE APPLICATION OF NEW SOURCE
PERFORMANCE STANDARDS ~ ~
Based upon the information contained in Sections III through VIII and in
the appendices of this report, a determination has been made that the
point source discharge standards for each identified pollutant shown in
Table 72 can be obtained through the application of proper technology.
247
-------
Subcategory
Unbleached
Kraft
NSSC - Ammonia
NSSC - Sodium
Unbleached
Kraft - NSSC
Paperboard from
Waste Paper
Table 72
New Source Performance Standards
Values in kg/kkg (Ibs/ton)
BOD5
30 Day
Daily Max
1.55 (3.1) 3.1 (6.2)
3.75 (7.5) 7.5 (15.0)
2.6 (5.2) 5.2 (10.U)
1.9 (3.8) 3.8 (7.6)
0.75 (1.5) 1.5 (3.0)
TSS
30 Day
3.75 (7.5)
3.75 (7.5)
3.85 (7.7)
U.O (8.0)
2.0 (4.0)
Daily Max
7.5 (15.0)
7.5 (15.0)
7.7 (15.U)
8.0 (16.0)
4.0 (8.0)
Subcategorv
Unbleached
Kraft
NSSC - Ammonia
NSSC - Sodium
Unbleached
Kraft - NSSC
Paperboard from
Waste Paper
Color
30 Day Daily Max
10 (20) 15 (30)
12.5 (25) 18.75 (37.5)
pH for all subcategories shall be within the range of 6.0 to 9.0
The maximum average of daily values for any 30 consecutive day period
should not exceed the 30 day standards shown above. The maximum for any
one day should not exceed the daily maximum standards shown above. The
standards are in kilograms of pollutant per metric ton of production
(pounds of pollutant per short ton of production). Effluents should
always be within the pH range of 6.0 to 9.0.
Production is defined as the annual average production off the machine
(air dry tons) .
248
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The TSS parameter is measued by the technique utilizing glass fiber
filter disks as specified in Standard Methods for the Examination of
Water and Wastewater, (13th Edition) ("T™
The color parameter is measued by methods described in NCASI Technical
Bulletin |253 (2). Color units are to be assumed equal to mg/1 in
determing kilograms (pounds) of color per metric ton (short ton) of
production.
IDENTIFICATION OF TECHNOLOGY TO ACHIgVE T.HE NEW SOURCE PERFORMANCE.
STANDARDS
The technology to achieve the new source performance standards should
consist of the bejt available control technology economically achievable
as described in Section X with the follow ng changes:
External Controls
Coagulation and filtration is not included for any of the subcategories.
Color reduction for NSSC - sodium base and NSSC - ammonia base mills is
not included.
RATIONALE FOR SELECTION OF TECHNOLOGY FOR NEW SOURCE PERFORMANCE
STANDARDS
Type of Process Employed and Process Changes
No radical new in-plant processes are proposed as a ...eans of achieving
new source performance standards for the subcategories studied. The
internal control technologies which are identified have all been
demonstrated in mills within thr subrategories uncu_-r study.
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. The primary areas of operational change will
pertain to required activities for recycle, reuse, and spill control, as
well as for optimal performance of waste water treatment facilities.
249
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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.
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 mills if an effective and
economical method for removal of nitrogen does not become available
through further study.
Use of Dry £ather 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 suffici-
ently 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 by-products 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 by-product sale the
recovery of which is not presently economically feasible.
250
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Cost of Application in gelation to Effluent ReductionirBenefits
Based upon the information contained in Section VIII and the Appendices
of this report, the total projected cost of NSPS technology reflects an
increase in production expenses as shown in Table 73 (1971 price index) .
Table 73
Cost of Application of NSPS
Subcategory
Unbleacned Kraft
NSSC-Sodium
NS S C -Ammon i a
Kraft-NSSC
Paperboard from
Waste Paper
Production
kkg/day
(tons/day)
907 (10CO)
227 (250)
227 (250)
907 (1000)
91 (100)
Total Annual
Cost Incl.
Energy
$2,198,000
$402,000
$526,000
$2,264,OCO
$103,000
Increase in Costs
$/kkg
$6.92 (6.28)
$5.06 (4.59)
$6.63 (6.01)
$7.13 (6.47)
$3.78 (3.43)
These increases reflect both all internal and external identified
control technologies. The increases are based on 350 days of production
per year except for paperboard from waste paper which is based on 300
days per year.
RATIONALE FOR DEVELOPMENT OF NEW SOURCE PERFORMANCE STANDARDS
The New Source Performance Standards are based upon the best
demonstrated control technology processes and operating methods as
determined for the subcategories under study. The standards were
developed by essentially the same methodology as described for the BATEA
limitations. The major differences, shown in Table 74, was not
including coagulation and filtration for TSS reduction and reverse
osmosis for color reduction in the identified technologies for new
sources, as these were determined to be not completely demonstrated in
the pulp and paper industry.
251
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TABLE 74
APPLICABLE EXTERNAL TECHNOLOGIES IN
DEVELOPMENT OF STANDARDS FOR NEW SOURCES
Raw Waste
kg/kkg Color Biological
Subcategory (Ibs/ton) Removal Treatment
Unbleached 12.5(25) X X
Kraft
NSSC- 17.5(35) X
Sodium
<3 NSSC- 25(50) X
Ammonia
Kraft- 15(30) X X
NSSC
Paperboard- 10(20) X
Waste Paper
-------
SECTION XII
ACKNOWLEDGEMENTS
The Environmental Protection Agency wishes to acknowledge the
contributions of WAPORA, Inc., and its subcontractors, E. C. Jordan Co.
and EKONO, Inc., who prepared the original draft of this document. The
efforts of Mr. E. N. Ross, Dr. Harry Gehm, Mr. William Groff, Dr. Howard
Eddy, and Mr. James Vamvakias are appreciated.
Craig D. Vogt, Project Officer, Effluent Guidelines Division, through
his assistance, leadership, advice, and reviews has made an invaluable
contribution in the preparation of this report. Mr. Vogt provided a
careful review of the draft report and the original Development Document
and suggested organizational, technical and editorial changes.
Special thanks are due George Webster, previously with the Effluent
Guidelines Division, for his efforts on the draft report and the
original Development Document.
Appreciation is expressed for the contributions of several individuals
within the Environmental Protection Agency: David Lyons of the Permit
Assistance and Evaluation Division, Kirk Willard and Ralph Scott,
National Environmental Research Center at Corvallis, Oregon; Irving
Susel of the Economic Analysis Division; Charles Cook of the Monitoring
and Data Support Division; and Richard Williams, Mark Moser, William
Kirk, John Riley, Ernst Hall, and Allen Cywin of the Effluent Guidelines
Division.
Appreciation is extended to Gary Fisher and Taffy Neuburg of the
Effluent Guidelines Division for their efforts in data handling and
computer analysis. The efforts of Karla Jean Dolum for her continuous
assistance throughout the project are appreciated. Thanks are also due
to the many secretaries who typed and retyped this document: Jan Beale,
Pearl Smith, Acqua Delaney, Karen Thompson, Jane Mitchell, Barbara
Wortman and Laura Noble.
The cooperation of the National Council for Air and Stream Improvement
in providing liaison with the industry and technical assistance were
invaluable assets, and this service is greatly appreciated. Thanks are
also extended to the American Paper Institute for its continued
assistance.
Appreciation is also extended to companies who granted access to their
mills and treatment works from field surveys and for the assistance lent
by mill personnel to field crews. The operation records furnished by
these manufacturers and information supplied by other individuals in the
industry contributed significantly to the project.
253
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SECTION XIII
REFERENCES
1. American Public Health Assn., (APHA), AWWA, WPCF, Standard Methods
for the Examination of Water and Wastewater, New York 1971.
2. National Council for Air and Stream Improvement, Inc. Technical
Bulletin 253, December 1971. ~
3. Buckley, D. B. and McKeown, J. J., An Analysis of the Performance
of Activated Sludge and Aerated Stabilization Basin Systems in
Controlling the Release of Suspended Solids in Treated Mill Effluents
to Receiving Waters, NCASI Special Report No^ 73-02, April 1973.
H. Buckley, D. B. and McKeown J. J., An Analysis of the Performance
of activated Sludge and Aerated Stabilization Basin Systems in
Controlling the Release of Suspended Solids in Treated Mill Effluents
to Receiving Waters, NCASI Special Report No. 73-03, August 1973.
5. Casey, J. P., Pulp and Paper, Chemistry and Chemical Technology,
Vol. I Pulping and Bleaching, 2nd Ed., Interscience Publishers, Inc.,
New York (1960).
6- Pulp and Paper Manufacture. Vol.__!_; The Pulping of good, 2nd Ed.,
McGraw-Hill Book Co., New York (1969).
7. Brown, R. W., et. al., "Semi-Chemical Recovery Processes and
Pollution Abatement, Pulp and Paper Magazine of Canada, T-202,
March (1960).
8. Paper, Paperboard, Wood Pulp Capacity/1971-1974, American Paper
Institute, October (1972) .
9. A Year of Environmental and Economic Progress in the Paper Industry,
American Paper Institute (1972).
10. Axelsson, O., "Some Views on Brown Stock Washing," International
Congress on Industrial Waste Water, Stockholm (1970).
11. Chemical Recovery in the Alkaline Pulping Processes. TAPPI
Monograph No. 32 (1968).
12. Gehm, H. W., State-of-the-Art Review of Pulp and Paper Waste
Treatment, EPA Contract No. 69-01-0012, April (1973).
13. Rydholm, S. A., Pulping Processes,Interscience Publishers ,
New York (1965) .
255
-------
l«t. Bryan, W. P., "Inland'jj Tennessee Mill Was First Designed for
Ammonia Base NSSC," Paper Trade Journal, September 25, (1972).
15. Moor, J. L., "Ammonia Base Sulphite Pulping at Inland Container,"
Paper Trade Journal, November 20, (1972),
16. Whitney, TAPPI Monograph #32.
17. Britt, K. W., Handbook of Pulp and Paper Technology,2nd Ed., Van
Nostrand Reinhold Co., New York (1970).
8• Pulp and Paper Manufacture, Vol. Ill; Papermakincf andnPaperbpard
Making. 2nd Ed., McGraw-Hill Book Co., New York (1970)
19. Kleppe, P. J., and Rogers, C. N., Survey of Water utilization and
Waste coiitrgj. Practices in the Southern Pulp and Paper Industry,
Water Resources Research Institute of the University of N.C.,
OWRR Project No. A-036-NC, June (1970).
20. Private Communication (19t"0) .
21. Kronis, H., and Holder, D. A., "Drum Barker Effluent," Pulp and
Paper Magazine of Canada, 69, 62 February (1968).
22. Draper, R. E., and Mercier, F. S., "Hydraulic Barker Effluent
Clarifier at Woods Products Division, Weyerhaeuser Co.," Proceed-
ings llth Pacific Northwest Industrial Waste Conf. (1962).
23. Blosser, R. O., "Practice in Handling Barker Effluents in Mills in
the United States," NCAS|_Teghn;Lcal^ Bulletin,,jo^.lga (1966).
2U. Pollutional Effects of Pulp and Papermill Wastes in Puget Sound,
FWQA, U.S. Dept. of the Interior (1967),
25. South, W. D., "New Approaches to In-Plant Land control and Monitoring,"
NgASJ TechnicalBulletin No, 248, Part II, 2 (1971).
26. Wilson, D. F. Johanson, L. N., and Hrutfiord, B. F., "Methanal,
Ethanal, and Acetone in Kraft Pulp Mill Condensate Streams,"
TAPPX-55, 8 (1972).
27. Estridge, R. B., Thibodeaux, L. J., et. al., "Treatment of Selected
Kraft Mill Wastes ift a Cooling Tower," TAPPI 7th Water and Air
Conf. (1970) .
28. Bergkvist, S., and Foss, E., "Treatment of contaminated Condensates
in Kraft Pulp Mills, "International Congress on Industrial Waste
Water, Stockholm (1970).
256
-------
29. Haynes, D. C., "Water Reuse — A Survey of Pulp and Paper Industry,"
TAPPI, 49. 9 (1966).
30. Vilbrant, F., "Report on Semi-Chemical Wastes," NCASI Technical
Bulletin, No. 28 (1949).
31. Voigts, D., Presentation at EPA-API Technical Hearing (April 4, 1974).
32. Lowe, K. E., "control of Effluent at a NSSC Mill by Reuse of White
Water," TAPPI 7th Water and Air Conf. (1970).
33. Nelson, W. R. et al., "Process Water Reuse and Upset Control
Modifications at an Integrated NSSC Mill," TAPPI Environmental
Conference (1973).
34. Michigan Water Resources Commission, "Reports on the Kalamazoo River."
35. Wisconsin Stdte Department of Health, Pulp and Paper Advisory
Committee Report (1965) .
36. Bishop, F. W., et al., "Biological Waste Treatment Case Histories
in the Pulp and Paper Industry," NgASI Technical Bulletin No. 220
(1968) .
37. Hrutfiord, B.F., el al.. Steam Stripping Ordorous Substances from
Kraft Effluent Streams, EPAJ-R2-73~164 (1973^.
38. Matteson, M.J., et al., "SEKOR II: Steam- Stripping of Volatile
Organic Substances from Kraft Pulp Mill Effluent Streams,"
TAPPI 50. 2 (1967).
39. Maahs, H.G., et al., "SEKOR III: Preliminary Engineering Design
and Cost Estimates for Steam Stripping Kraft Pulp Mill Effluents,"
TAPPI 50. 6 (1967).
40. Fry, Keith, Presentation at EPA-API Technical Hearing (April 4, 1974).
41. Gould, M., and Walzer, J., "Mill Waste Treatment by Flotation."
42. Timpe, W.G., Lang, E., and Miller, R.L., Kyaft Pulping Effluent
Treatment and Reuse - State of the Art, Environmental Protection
Technology Series EPA-&2-73-164 (1973).
43. Edde, H_, "A Manual of Practice for Biological Waste Treatment
in the Pulp and Paper industry," NCASI Technical Bulletin No. 214
(1968) .
44. Gellman, I., "Aerated Stabilization Basin Treatment of Mill
Effluents," NCASJC^Technical Bulletin No. 185 (1965).
257
-------
45. Amberg, Herman, Crown Zellerbach Corp., Camas, Washington (March 1974)
46. Fair, Geyer, Okun, Water and Wastewater Engineering.
John Wiley & Sons, 1968.
47. Follett, R., and Gehm, H. W., "Manual of Practice for Sludge
Handling in the Pulp and Paper Industry," NCASI Technical
Bulletin No. 190 (1966).
48. Lindsey, A. M., "Dewatering Paper Mill Sludges by Vaccum Filtration,"
Purdue University Industrial Waste Conference XXIII (1968).
49. Voegler, J., "Drainability and Dewatering of White Water Sludges,"
NCASI Technical Bulletin No^ 35 (1950).
50. Stovall, J. H., and Berry, D. A., "Pressing and Incineration of
Kraft Mill Primary Clarification Sludge," TAPPI 6th Water and Air
Conf. (1969).
51. Aspitrate, T. R., et. al., "Pulp and Paper Mill Sludge Utilization
and Disposal," TAPPI Environmental Conf. (1973).
52. Coogan, F. J., and Stovall, J. H., "Incineration of Sludge from
Kraft Pulp Mill Effluents," NCASI_Technical_Bulletin No. 185 (1965)
53. Bishop, F. W., and Drew, A. E., "Disposal of Hydrous Sludges from
a Paper Mill," TAPPI Water and Air Conf. (1971)
54. Harkin, J. M., and Crawford, D. L., "Bacterial Protein from Paper
Mill Sludges," TAPPI Environmental Conf. (1973).
55. Berger, H. F., "Development of an Effective Technology for Pulp
and Bleaching Effluent Color Reduction," NCASI Technical Bulletin
No. 228 (1969).
56. Spruill, E. L., Draft of final report. Color Removal and Sludge
Disposal Process for Kraft Mill Effluents, EPA Project f12040
DRY (1973)
57. "Treatment of Calcium-Organic Sludges Obtained From Lime Treatment
of Kraft Pulp Mill Effluents - Part I," NCASI Technical Bulletin
No. 62 (1955) .
58. "Treatment of Calcium-Organic Sludges from Lime Treatment of Kraft
Pulp Mill Effluents - Part KK," NCASIJTechnical^Bulletin No. 75,
(1955).
258
-------
59. Interstate Paper Corp., Color, Remoyaj. from Kraft Pulping Effluent
by Lime Addition, EPA Grant #~WPRD~183-01-68, December 1971.
60. Oswalt, J. L., and Lund, J. G., Jr., Color Removal from Kraft
Pulp Mill Effluents by Massive Lime Treatment, EPA Project 12040
DYD (1973)7
61. Davis, C. L., Color Removal from Kraft Pulping Effluent by Lime
Addition, Interstate Paper Corporation, EPA Project 120UO ENC
(1971).
62. Spruill, E. L., Color Removal and Sludge Recovery from TotalMj.ll
Effluent, TAPPI Environmental Conference, Houston, Texas (1972) .
63. Spruill, E.L., "Long Term Experience with Continental Can's Color
Removal System." TAPPI Environmental Conference, New Orleans, La.,
April 1974.
64. Smith, S. E., and Christman, R. F., "Coagulation of Pulping
Wastes for the Removal of Color," Journal of the Water Pollution
Control Feder ation, V. 41, No. 2, Part I™ 19 6 9) 7
65. Middlebrooks, E. J., et. al, "Chemical Coagulation of Kraft Mill
Wastewater," Water and SSwage, Works, V. 116, No. 3 (1967).
66. Smith, D. R., and Berger, H. F., "Waste Water Renovation," TAPPI,
51, 10 (1968).
67. Berger, H. F., and Thibodeaux, L. J., "Laboratory and Pilot Plant
Studies of Water Reclamation," NCASI Technical Bulletin No. 203
(1967).
68. McGlasson, W. G., et. al., "Treatment of Pulp Mill Effluents With
Activated Carbon," NCASI Technical_Buj.letin_No,.._199 (1967) .
69. Timpe, W. G., and Lange, E. W., "Activat'ed Carbon Treatment of
Unbleached Kraft Effluent for Reuse, Pilot Plant Studies," TAPPI
Environmental Conference (1973).
70. Private Communication, St. Regis Paper Company, 1973.
71. Smith, D. R., and Berger, H. F., "Waste Water Renovation," TAPPI
51 (1968) .
72. Private Communication, Uddeholms Aktiebolag, Skoghall, Sweden, Feb. 1974.
73. Private Communication, Dow chemical Co., May 1974.
74. Rock, S. L., Kennedy D.C., and Bruner, A., "Decolorization of
Kraft Mill Effluents with Polymeric Absorvents," Presented at
259
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TAPPI Environmental Conference, New Orleans, La., April 1974.
75. Envirocon Ltd., Vancouver, Canada, "Ion Flotation for Colour Removal
from Kraft Mill Effluents." Progress Summary No. 3 (c). August 1973.
76. Fremont, H. A., Tate D.C., and Goldsmith, R.L., Color Removal
from Kraft MillTEffluents by Ultrafiltratipn. EPA-660/2-73-019,
December 1973.
77. Pulp and Paper Reserach Institute of Canada, Pointe Claire, Que.,
The Use of High Molecular Weight Amines for the Purification of Pulp
Mill Effluents, Project Report 1-2, Environment Canada Forestry
Service, September 1971.
78. Gulp, R. L., and Gulp, G. L., Advanced Waste Treatment. Van
Nostrand Reinhold, New York (1971).
79. Coates, J., and McGlasson, W. G., "Treatment of Pulp Mill
Effluents With Activitated Carbon," NCASI Technical Bulletin No^
199 (1967).
80. Hansen, S. P., and Burgess, F. J., "Carbon Treatment of Kraft
Condensate Wastes," TAPPI,, 51, 6 (1968).
81. Weber, W. J., Jr., and Morris, J. C., "Kinetics of Adsorption in
Columns of Fluidized Media," Journal WPCF, 37, 4 (1965).
82. Davies, D. S., and Kaplan, R. A., "Activated Carbon Eliminates
Organics," Chemical Engineering Progress, 60, 12 (1964).
83. Bishop, D. F., et al., "Studies on Activated Carbon Treatment,"
Journal WPCF. 39, 2 (1967).
84. Vanier, C., et al.. Carbon Column Operation in Waste Water Treatment,
Syracuse University, Syracuse, New York, Nov. (1970).
85. Timpe, W. G., et al., "The Use of Activated Carbon for Water Renovation
in Kraft Pulp and Paper Mills," Seventh TAPPI Water and Air
Conference (1970).
86. Beebe, R. L., and Stevens, J. I., "Activated Carbon System for
Wastewater Renovation," Water and Wastes Engineering, Jan. (1967).
87. Eckenfelder, W. W., Jr., Krenkel, P. A., and Adams, C. A.,
Advanced Waste Water Treatment. American Institute of Chemical
Engineers, New York (1972).
88. Holm, J. D., "A Study of Treated Wastewater Chlorination," Water
and Sewage Works, April (1973).
260
-------
89. Meiners, A. F.f Light-Catalyzed Chlorine Oxidation for Treatment
of Wastewater, Midwest Research Institute, for Water Quality
Office, EPA, September (1970).
90. 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).
91. 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).
92. Nelson, W. R., and Walraven, G. O., "A Role for Reverse Osmosis
in a Neutral Sulfite Semichemical Pulp and Paperboard Mill,"
Purdue University Industrial Waste Conf. XXIII (1968).
93. Morris, D. C., Nelson, W. R., and Walraven, G. O., "Recycle of
Papermill Waste Waters and Application of Reverse Osmosis,"
ORM, EPA Program f12040 FUB, January (1972).
94. Leitner, Gordon F., "Reverse Osmosis For Waste Water Treatment -
What: When?, TAPPI 8th Water 8 Air Conference (1971).
95. Morris, D.C., Nelson, W.R., and Walraven, G.O., Recycle of
Papermill Waste Waters and Application of Reverse Osmosis,
ORM, EPA Program #12040 FUB, Jan. (1972) .
96. 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).
97. 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).
98. Beder, H., and Gillespie, W. J., "The Removal of Solutes From
Pulp Mill Effluents by Reverse Osmosis," TAPPI_53, 5 (1970).
99. Bishop, H. K., Use of Unproved Membranes in Tertiary Treatment by
Reverse Osmosis, McDonnell Douglas Astronautics Company for EPA,
Program #17020 DHR, Dec. (1970).
100. 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) .""
261
-------
101. Optimization of Ammonia Removal by Ion Exchange Using Clinoptilo-
lite. University of California for EPA, Project #17080 DAP,
Sept. (1971).
102. Wastewater Ammonia Removal by Ion Exchange, Battelle-Northwest
for EPA,~Project~#170lO EEZ, Feb. (1971)7
103. Johnson, Walter K., and Vania, George B., Nitrification and
Devitrification of Waste Water, University of Minnesota for
EPA, Research Grant Number WP 01028, January (1971).
104. Nitrogen^ Remgyal^From Wastewaters, Federal Water Quality Research
Laboratory, Advanced Waste Treatment Research Laboratory,
Cincinnati, Ohio, Oct.. (1970).
105. Shindala, Adnan, "Nitrogen and Phosphorus Removal From Waste-
waters - Part I," Water and Sewage Works. June (1971).
106. Shindala, Adnan, "Nitrogen and Phosphorus Removal From Waste-
waters - Part II," Water and Sewage works, July (1971).
107. Young, James C., Advanced Waste Water Treatment Concepts, General
Filter Co.
108. sludge Dewatering, Manual of Practice No. 20, FWPCA (1969).
1C9. Gehm, H. W., "Effects of Paper Mill Wastes on Sewage Treatment
Plant Operation," Sewage Works.Journal, 17, 510 (1945).
110. Gellman, I., "Reduction of Paper, Paperboard and Weak Pulping
Wastes by Irrigation," Pulp and Paper Magazine of Canada, T-221,
March (1960) .
111. Vercher, B. D., et. al., "Paper Mill Waste Water for Crop
Irrigation and Its.Effects on the Soil," Louisiana State Univ.,
Agriculturgl_Exp.erimeQt Station Bulletin No. 60U. (1965) .
112. Voights, D., "Lagooning and Spray Disposal of NSSC Pulp Mill
Liquors," Purdue University Industrial Waste Conference X (1955).
113. Hendrickson, E. R., et al.. Control of^Atmospheric Emissions in
the^Wogd Pulping Industry, DREW, NAPCA Contract No. CPA 22-69-18,
March (1970).
11U. Drew, J., and Pyland, G. D., Jr., "Turpentine from the Pulpwoods
of the United States and Canada," TAPPI_U9, 10 (1966).
115. Resource Engineering Associates, "State of the Art Review on
Product Recovery," FWPCA Contract No. ltt-12-495, Nov. (1969) .
262
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116. Ellenbe, R. W., "Why, Where, and How U.S. Mills Recover Tall Oil
Soap," Paper Trade Journal. June 25 (1973).
117. Barton, J. S., "Future Technical Needs and Trends of the Paper
Industry, By-Products Usages," TAPPI 56. 6 (1973).
118. "Availability of Construction Manpower," Engineering News Record,
June 7 (1973).
263
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SECTION XIV
GLOSSARY
Act
Federal Water Pollution Control Act, as amended in 1972.
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 the
liquor being incinerated 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.
Cbemi-;>Mecbanical Pulp
Pulp produced mechanically by grinding or refining after presoaking of
wood with caustic soda/sodium sulfite solution.
265
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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 NCASI methods.
Consistency
A 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
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.
Denitrification
Bacterial mediated reduction of nitrate to nitrite. Other bacteria may
act on the nitrite reducing it to ammonia and finally N2 gas. This
reduction of nitrate occurs under anaerobic conditions. The nitrate
266
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replaces oxygen as an election acceptor during the metabolism of carbon
compounds under anaerobic conditions.
Digester
A pressure vessel used to cook wood chips in the presence of cooking
liquor and heat.
Dregs
The inert rejects from the green liquor clarifier of a pulp mill.
External treatment
Technology applied to raw waste streams to reduce pollutant levels.
Extraction Water
Water removed during a pulp manufacturing process.
An endless belt of wool or plastic used to convey and dewater the sheet
during the papermaking process.
The cellulosic portion of the tree used to make pulp, paper and paper-
board.
Eurnish
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."
The type of pulp or paper product manufactured.
267
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Green Liquor
Liquor made by dissolving chemicals recovered from the kraft process in
water and weak liquor preparatory to causticizing.
In Plant Measures
Technology applied within the manufacturing process to reduce or
eliminate pollutants in the raw waste water. Sometimes called "internal
measures" or "internal controls".
Nitrification
Bacterial mediated oxidation of ammonia to nitrite. Nitrite can be
further oxidized to nitrate. These reactions are brought about by only
a few specialized bacterial species. Nitrosomonias sp. and Nitrpcoccus
sp. oxidize ammonia to nitrite which is oxidized to nitrate by
Nitrobacter sp.
Nitrogen fixation
Biological nitrogen fixation is carried on by a select group of bacteria
which take up atmospheric nitrogen (N2) and convert it to amine groups
or for amino acid synthesis.
Packing Water
See Gland water.
Pulp
Cellulosic fibers after conversion from wood chips.
A mechanical device resembling a large-scale kitchen blender used to
separate fiber bundles in the presence of water prior to papermaking.
Rejects
Material unsuitable for pulp or papermaking which has been separated in
the manufacturing process.
Sanitary Landfill
A sanitary landfill is a land disposal site employing an engineered
method of disposing of solid wastes on land in a manner that minimizes
environmental hazards by spreading the wastes in thin layers, compacting
the solid wastes to the smallest practical volume, and applying cover
material at the end of each operating day.
268
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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.
Shjves
Bundles of fiber which have not been defiberized.
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
Sulfidity is a measure of the amount of sulfur in kraft cooking liquor.
It is the percentage ratio of Nas, expressed as NaO, 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 wire of a paper machine which contains
fiber, filler, and chemicals.
269
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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.
270
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I
II
III
Figure 1
2
3
U
5
6
7
IV Exhibit 1
Exhibit 2
Figure 8
APPENDICES
List of Mills per Subcategory
NPDES Data
Development of Costs
Spill Control Installations
Spill Basin and Controls
Page
273-287
289-292
293
301
302
VI
VII
Capital and Operation Cost for Raw Waste Screening
306
Construction Cost of Earthern Settling Ponds 308
Capital and Operating Cost for Mechanical Clarifiers
309
Aerated Lagoon Treatment Plant 311
Completely Mixed Activated Sludge 314
Preliminary Mill Survey Format 323-325
Verification Program - Detailed Instructions
for Field Survey Teams. 326-332
NCASI Color Measurement Technique 333-336
Typical Calibration Curve 336
Abbreviations 337-338
Conversions 339
271
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APPENDIX I
MILLS LISTED BY SUBCATEGORY
UNBLEACHED KRAFT MILLS
Georgia Kraft Co.
Mahrt, Alabama
Union Camp Corp
Montgomery, Alabama
MacMillan Bloedel United, Inc.
Pine Hill, Alabama
Gulf States Paper Corp.
Tuscaloosa, Alabama
International Paper Co.
Camden, Arkansas
Arkansas Kraft Corp.
Morrilton, Arkansas
Weyerhaeuser Co.
Pine Bluff, Arkansas
Alton Box Board Co.
Jacksonville, Florida
St. Regis Paper Co.
Jacksonville, Florida
Georgia Kraft Co.
Krannert, Georgia
Georgia Kraft Co.
Macon, Georgia
Continental Can Co., Inc.
Port Wentworth, Georgia
Interstate Paper Corp.
Riceboro, Georgia
273
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Owens-Illinois, Inc.
Valdosta, Georgia
Unijax, Inc.
Elizabeth, Louisiana
Pineville Kraft Corp.
Pineville, Louisiana
St. Regis Paper Co.
Monticello, 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
Westvaco Corp.
Charleston, South Carolina
South Carolina Industries, Inc.
Florence, South Carolina
Tennessee River Pulp £ Paper Co.
Counce, Tennessee
Owens-Illinois, Inc.
Orange, Texas
crown Zellerbach Corp.
1'ijit Towrisend, Washington
-------
KRAFT-NSSC MILLS
Great Northern Paper Co.
Cedar Springs, Georgia
Union Camp Corp.
Savannah, Georgia
International Paper Co.
Bastrop, Louisiana
Continental Can Co.
Hodge, Louisiana
Continental Can Co.
Hopewell, Virginia
Container Corp. of America
Fernandina Beach, Florida
Olinkraft, Inc.
West Monroe, Louisiana
Weyerhaeuser Co.
Valliant, Oklahoma
Western Kraft Corp.
Albany, Oregon
Boise Cascade Corp.
Wallula, Washington
275
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NSSC MILLS (SODIUM BASE)
Weston Paper and Mfg. Co.
Terre Haute, Indiana
Celotex Corp.
Dubuque, Iowa
Consolidated Packaging Corp.
Fort Madison, Iowa
Wescor Corp.
Hawesville, Kentucky
Hoerner Waldorf Corp.
Ontonagon, Michigan
Menasha Corp.
Otsego, Michigan
Hoerner Waldorf Corp.
St. Paul, Minnesota
Container Corp. of America
Circleville, Ohio
Stone Container Corp.
Coschocton, Ohio
Celotex Corp.
Sunbury, Pennsylvania
Mead Corp.
Harriman, Tennessee
Mead Corp.
Lynchburg, Virginia
Green Bay Packaging, Inc.
Green Bay, Wisconsin
Menasha Corp.
North Bend, Oregon
276
-------
NSSC MILLS (AMMONIA BASE)
Mead Corp.
Sylva, North Carolina
Inland Container Corp.
New Johnsonville, Tennessee
277
-------
PAPERBQARD FROM WASTE PAPER MILLS _IN_TJj.E U.S.
National Gypsum Co.
Anniston, Alabama
Stone Container Corp.
Mobile, Alabama
Sonoco Products Co.
City of Industry, California
Container Corp. of America
Los Angeles, California
Fontana Papers Inc.
Fontana, California
Federal Paper Board Co., Inc.
Los Angeles, California
Fiberboard Corp.
Los Angeles, California
L.A. Paper Box & Board Mills
Los Angeles, California
America Forest Products Corp.
Newark, California
Western Kraft Corp.
Port Hueneme, 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
Speciality Paper Mills Inc.
Santa Fe Springs, California
U.S. Gypsum Co.
South Gate, California
278
-------
Fibreboard Corp.
Stockton, California
Fibreboard Corp.
Vernon, California
Packaging Corp. of America
Denver, Colorado
Colonial Board Co.
Manchester, Connecticut
Robertson Paper Box Co.
Montville, Connecticut
Federal Paper Board Co., Inc.
New Haven, Connecticut
Simkins Industries, Inc.
New Haven, Connecticut
Federal Paper Board Co., Inc.
Versailles, Connecticut
Container Corp. of America
Wilmington, Delaware
U.S. Gypsum Co.
Jacksonville, Florida
Simkins Industries, Inc.
Miami, Florida
Sonoco Products Co.
Atlanta, Georgia
Austell Box Board Corp.
Austell, Georgia
Alton Box Board Co.
Cedartown, Georgia
Alton Box Board Co.
Alton, Illinois
Aurora Paperboard Co.
Aurora, Illinois
Container Corp. of America
Chicago, Illinois
279
-------
Prairie State Paper Mills
Joldet, Illinois
Nabisco, Inc.
Marseilles, Illinois
Federal Paper Board Co., Inc.
Morris, Illinois
Quaker Oats Co.
Pekin, Illinois
Packaging Corp. of America
Quincy, Illinois
Sonoco Products Co.
Rockton, Illinois
Kieffer Paper Mills, Inc.
Brownstown, Indiana
Container Corp. of America
Carthage, Indiana
Clevepak Corp.
Eaton, Indiana
Beveridge Paper Co.
Indianapolis, Indiana
Alton Box Board Co.
Lafayette, Indiana
Vincennes Paper Mills Inc.
Vincennes, Indiana
Container Corp. of America
Wabash, Indiana
Packaging Corp. of America
Tama, Iowa
Packaging Corp. of America
Hutchinson, Kansas
Lawrence Paper Co.
Lawrence, Kansas
Yorktowne Paper Mills of Maine, Inc.
Gardiner, Maine
280
-------
Keys Fibre Co.
Waterville, Maine
Chesapeake Paper Board Co.
Baltimore, Maryland
Simkins Industries, Inc.
Cantonsville, Maryland
Simkins Industries, Inc.
Ilchester, 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
Perket Folding Box Corp.
Hyde Park, Massachusetts
Lawrence Paperboard Corp.
Lawrence, Massachusetts
Newark Boxboard Co.
Natick, Massachusetts
West Dudley Paper Co.
West Dudley, Massachusetts
Michigan Carton Co.
Battle Creek, Michigan
Simplex Industries
Constantine, Michigan
Packaging Corp. of America
Grand Rapids, Michigan
Brown Co.
Kalamazoo, Michigan
National Gypsum Co.
Kalamazoo, Michigan
281
-------
Consolidated Packaging Corp.
Monroe, Michigan
Time Container Corp.
Monroe, Michigan
Union Camp Corp.
Monroe, Michigan
Mead Corp.
Otsego, Michigan
Simplex Industries Inc.
Palmyra, Michigan
Rockford Paper Mills, Inc.
Rockford, Michigan
Weyerhaeuser Co.
White Pigeon, Michigan
U.S. Gypsum Co.
N. Kansas City, Missouri
Brown Products
Nashua, New Hampshire
Hoague Sprague Div., USM Corp.
West Hopkinton, New Hampshire
MacAndrews & Forbes Co.
Camden, New Jersey
U.S. Gypsum Co.
Clarks, New Jersey
Whippany Paper Board Co.
Clifton, New Jersey
Georgia-Pacific Corp.
Delair, New Jersey
National Gypsum Co.
Garwood, New Jersey
Boyle Co.
Jersey City, New Jersey
Davey Co.
Jersey City, New Jersey
282
-------
National Gypsum Co.
Millington, New Jersey
Newark Boxboard Co.
Newark, New Jersey
Morris Paper Board Co.
Patterson, New Jersey
Lowe Paper Co.
Ridgefield, New Jersey
Lincoln Paper Mills, Inc.
Ridgefield Park, New Jersey
Whippany Paper Board Co.
Whippany, New Jersey
Sonoco Products Co.
Amsterdam, New York
Latex Fiber Industries
Beaver Falls, New York
Laxtex Fiber Industries
Brownville, New York
Georgia Pacific Corp.
Buchanan, New York
Climax Mfg. Co.
Carthage, New York
Brown Co.
Castleton-on-Hudson, New York
Columbia Corp.
Chatham, New York
Cornwall Paper Mills Co.
Cornwall, New York
Sealright, Inc.
Fulton, New York
Beaverboard Co., Inc.
Lockport, New York
Martisco Paper Co., Inc.
Marcellus, New York
283
-------
Columbia Corp.
North Hoosick, New York
Boundary Paper Mills, Inc.
North Tonawanda, New York
U.S. Gypsum Co.
Oakfield, New York
Clevepak Corp.
Piermont, New York
Federal Paper Board Co., Inc.
Piermont, New York
Cottrell Paper Co. Inc.
Rock City Falls, New York
Foster Paper Co. Inc.
Utica, New York
Warrensburg Board & Paper Corp.
Warrensburg, New York
Columbia Corp.
Waloomsac, New York
Carolina Paper Board Corp.
Charlotte, North Carolina
Federal Paper Board Co.
P.oanoke 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
284
-------
U.S. Gypsum Co.
Gypsum, Ohio
Tecomseh Corrogated Box Co.
Jaite, Ohio
Loroco Industries, Inc.
Lancaster, Ohio
Diamond International Corp.
Lockland, Ohio
Chipboard Inc.
Massilon, Ohio
Massilon Paper Co.
Masilon, Ohio
Interstate Folding Box Co.
Miamisburg, Ohio
Continental Can Co. Inc.
Middleton, Ohio
Diamond International Corp.
Middletown, Ohio
Middletown Paperboard Co.
Middletown, Ohio
Sonoco Products Co.
Munroe Falls, Ohio
Packaging Corp. of America
Rittman, Ohio
Federal Paperboard Co., Inc.
Steubenville, Ohio
Toronto Paperboard Co.
Toronto, Ohio
National Gypsum Co.
Pryor, Oklahoma
Georgia - Pacific Corp.
Pryor, Oklahoma
Packaging Corp. of America
Delaware Water Gap, Pennsylvania
285
-------
Brandywine Paper Corp.
Downingtown, Pennsylvania
Sonoco Products Co.
Downingtown, Pennsylvania
American Paper Products Co.
Eden, Pennsylvania
American Paper Products Co.
Lancaster, Pennsylvania
Henry Molded Products Inc.
Lebanon, Pennsylvania
National Gypsum Co.
Milton, Pennsylvania
Connelly Containers Inc. of Philadelphia
Philadelphia, Pennsylvania
Container Corp. of America
Philadelphia, Pennsylvania
Crown Paper Board Co.
Philadelphia, Pennsylvania
Newman & Co., Inc.
Philadelphia, Pennsylvania
Beacon Paper Co.
Reading, Pennsylvania
Federal Paper Board Co., Inc.
Reading, Pennsylvania
Interstate Intercorr Corp.
Reading, Pennsylvania
Whippany Paper Board Co.
Riegelsville, Pennsylvania
Packaging Corp. of America
Stroudsburg, Pennsylvania
Westvaco Corp.
Williamsburg, Pennsylvania
St. Regis Paper Co.
York, Pennsylvania
286
-------
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. (2 mills)
Richmond, Virginia
Container Corp. of America
Tacoma, Washington
Fibreboard Corp.
Sumner, Washington
Halltown Paper Board Co.
Halltown, West Virginia
Banner Fibreboard Co.
Wellsburg, West Virginia
Beloit Box Board Co,
Beloit, Wisconsin
Menasha Corp.
Menasha, Wisconsin
St. Regis Paper Co.
Milwaukee, Wisconsin
U.S. Paper Mills Corp.
West De Pere, Wisconsin
287
-------
-------
Appendix II
NPDES DATA
UNBLEACHED KRAFT LINERBOARD MILLS
Mill
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Tons/ -Treatment
Day C L ASB AS SO SS CD
650 X
450 X
900 X X
940 X X
1000 X x X
1000 X x
900 X X
206 X X
1150 X x
1670 XX L
1200 X X L X
1585 X X
850 X x L
600
1000 X
750 X X
625 X
650 X X
1670 X X
1000 X
Flow
G/Ton
xlOOO
16.7
21.0
10.0
21.0
17.0
11.75
23.0
17.5
14.7
10.1
7.1
10.4
13.7
23.3
14.5
11.2
9.1
29.5
10.1
13.0
Discharge
TSS
/'/Ton
1.1
1.0
1.67
2.8
1.2
5.0
3.4
7.6
10.0*
5.8
36.0
0.56
16.8
5.9
34.2
24.1
10.3
35.5
34.8
3.7
20.8
BOD
///Ton
0.4
0.9
1.25
1.3
1.5
3.7
4.0
11.5
4.0*
2.3
6.5
3.2
10. 1
5.2
42.5
27.2
19.6
56.1
9.4
6.5
36.3
*Council of Economic Priorities Report 8/72
289
-------
Unbleached Kraft Linerboard Mills - Cont'd.
Flow
Discharge
Mill
No.
21
22
23
Tons/ Treatment
Day C L ASB AS SO SS
410 X
1450 X L
1250
G/Ton
CD xlOOO
75.8
6.3
30.4
40.0*
TSS
-------
NEUTRAL SULFITE SEMI-CHEMICAL MILLS (AMMONIA BASE)
Mill
No.
1
Mill
No.
1
2
3
4
5
6
7
8
9
10
*Council
Mill
No.
1
2
Tons/ Treatment
Day C L ASB AS SO SS CD
500 X X X
COMBINATION KRAFT AND NSSC MILLS
Tons/ Treatment
Day C L ASB AS SO SS CD
1320 X
1600 X X
2100 XX X
1955 X
666 X
1030 X
820 X X
770 X X
1680 X X
1464 XX L x
of Economic Priorities Report 8/72
PAPERBOARD FROM WASTE PAPER
Tons/ Treatment
Day C L ASB AS SO SS CD
125 X X L
115 X L
Flow
G/Ton
xlOOO
8.6
Flow
G/Ton
xlOOO
19.1
10.6
20.0
7.7
10.5
20.3
16.6
8.0
27.9
25.3
Flow
G/Ton
xlOOO
16.0
0.01
Discharge
TSS
///Ton
6.5
BOD
/'/Ton
18.0
Discharge
TSS
///Ton
4.7
7.4
12.7
10.3
10.0*
25.4
35.0*
26.8
42.0*
5.3
1.5
320.0
5.4
BOD
///Ton
2.0
7.3
6.0
13.0
12.0*
33.9
26.0
40.0
41.0*
8.8
3.1
132.0
9.4
Discharge
TSS
#/Ton
0.34
.07
BOD
///Ton
0.4
0.4
*Council of Economic Priorities Report 8/72
291
-------
Paperboard from W'as'te. Paper Mills- cont'd.
Flow
Discharge
Mill
No.
3
4
5
6
7
8
9
10
11
1 0
13
14
15
16
Tons/
Day
240
804
80
59.1
165
122
90
275
320
971;
250
850
150
80
C
X
X
X
X
X
X
X
X
X
X
X
Treatment G/Ton
L ASB AS SO SS CD xlOOO
L 8.4
X C 7.6
X 12.5
X 11.9
X L 4.6
5.7
X C 10.0
X L 2.3
X 8.4
X X 1.2
X X 3.5
0.18
X X
TSS
#/Ton
0.5
5.1
10.6
0.25
5.6
14.2
4.6
2.5
6.0
•51 f.
0.7
0.5
o.oo
BOD
#/Ton
21.1
2.7
0.3
0.17
7.4
15.3
3.0
1.0
1.4
Uc
0.1
0.4
.003
292
-------
Appendix III
Development of Costs
Pretreatment Technology
Internal Measures
The internal measures can be summarized as follows:
907 kkg/day (1000 tons/day) unbleached kraft linerboard
mill and 907 kkg/day (1000 tons/day) kraft - NSSC mill
-addition of spill collection provisions for chemicals and fibers
-installation of low volume, high pressure self cleaning showers on
all paper machines
-filtering and reuse of press waters
907 kkg/day (1000 tons/day) paperboard from waste paper mill
-land disposal of junk materials
-installation of low volume, high pressure self cleaning showers on
paper machines
-filtering and reuse of press water
227 kkg/day (250 tons/day) NSSC - Na mill
-addition of liquor recovery system
-installation of low volume, high pressure self cleaning showers on
paper machines
-filtering and reuse of press water
External Treatment
For all case mills the liquid external treatment consists of raw waste
screening by bar screens, primary treatment by mechanical clarifiers,
foam control, effluent monitoring and automatic sampling and outfall
system by diffuser.
The screenings are burned in bark burners in case of the kraft
linerboard mill, the kraft - NSSC mill and the NSSC - Na mill. The
screenings are sanitary landfilled in case of the paperboard from waste
paper mills.
The sludge is dewatered by vacuum filter and sludge press and sanitary
landfilled for kraft linerboard and kraft - NSSC mills, while the sludge
293
-------
is dewatered by vacuum filters and sanitary landfilled for the
paperboard waste paper mill and the NSSC - Na mill.
BPCTCA Technology
Internal Measures
The internal measures to bring the base mills up to BPCTCA technology
consist of the additions already made plus the following:
907 kkg/day (1000 tons/day) unbleached kraft linerboard mill and 907
kkg/day (1000 tons/day) kraft - NSSC mill
-evaporator boil-out storage tanks
-pressure screening (hot-stock)
-segregation and reuse of white waters
-collection and reuse of vacuum pump seal waters
-installation of savealls, and
-gland water reduction
907 kkg/day (1000 tons/day) paperboard from waste paper mill, 227
kkg/day (250 tons/day) NSSC - Na base mill and 227 kkg/day (250
tons/day) NSSC - NH3 base mill
-segregation and reuse of white waters
-collection and reuse of vacuum pump seal waters
-installation of savealls, and
-gland water reduction
External Measures
Screening, primary, and secondary treatment are provided to total mill
effluents for all case mills, where the screening is by bar screens and
primary sedimentation in mechanical clarifiers as was used when the
upgrading was done in the previous upgrading step.
Secondary treatment is provided by nutrient addition, aerated lagoon
treatment and biological solids separation in mechanical clarifiers. An
emergency spill basin is installed prior to the secondary treatment
step.
Foam control, flow monitoring and sampling and outfall system are as
used under previous upgrading step.
The solids dewatering and disposal process is the same as the one used
in the previous upgrading step.
BATEA Technology
294
-------
Internal Measures
The internal measures to bring the base mills up to BATEA consist of
BPCTCA installations plus the following additions:
907 kkg/day (1000 tons/day) unbleached kraft linerboard mill, 907
kkg/day (1000 tons/day) kraft - NSSC mill, 227 kkg/day (250
tons/day) NSSC - Na base mill, and 227 kkg/day (250 tons/day) NSSC -
NH3 base mill
-expanded process water reuse
-separation of cooling water and recovery of heat
91 kkg/day (1000 tons/day) paperboard from wastepaper mill
-no additional installations beyond those selected to bring these
mills up to BPCTCA.
External Measures
All mill effluents are screened by bar screens and are subjected to
primary solids separation in mechanical clarifiers and secondary
treatment by nutrient addition, activated sludge treatment and secondary
solids separation in mechanical clarifiers. An emergency spill basin is
provided prior to the secondary treatment step.
The 907 kkg/day (1000 tons/day) kraft linerboard mill, and the 907
kkg/day (1000 tons/day) kraft - NSSC mill effluents receive color
removal by lime treatment. The 227 kkg/day (250 tons/day) NSSC - sodium
base and ammonia base mills have reverse osmosis systems for color
removal.
All mill effluents receive further solids reduction by mixed media
filtration.
All mill effluents receive foam control treatment, monitoring and
automatic sampling prior to entering the receiving waters through
diffusers.
Screenings from the linerboard mill and the kraft - NSSC mill effluents
are burned in sludge incinerators, and screenings from the NSSC - Na and
NSSC - NH3 base mills are burned in existing bark boilers.
Primary sludges and waste activated sludge are thickened in gravity
sludge thickeners, and dewatered mechanically by vacuum filters and
presses prior to ultimate disposal.
295
-------
Ultimate sludge disposal for the kraft linerboard mill and the kraft -
NSSC mill is by incineration, and for the other mills by sanitary
landfilling.
NSPS Technology
Internal Measures
Internal measures are not costed because such measures are included in
the design of new mills.
External Measures
All mill effluents are screened, receive primary solids separation in
mechanical clarifiers, and secondary treatment by nutrient addition,
activated sludge treatment and secondary solids separation by mechanical
clarifiers. Emergency spill basins are provided ahead of the secondary
treatment step.
All effluents receive foam control, monitoring and automatic sampling
prior to outfall by diffusers.
The 907 kkg/day (1000 tons/day) unbleached kraft and kraft - NSSC (cross
recovery) mill effluents receive color removal by lime treatment.
Screenings from the kraft linerboard mill, the kraft - NSSC mill, the
NSSC - Na and the NSSC - NH3 mills are burned in existing bark burners.
The screenings from the other mills are disposed of by sanitary land-
filling.
Primary sludge and wasted activated sludge are thickened in gravity
thickeners prior to mechanical dewatering by vacuum filters and presses.
Sludges from the kraft linerboard mill and the kraft - NSSC mill are
incinerated, while all other sludges are disposed of by sanitary land-
filling.
INTERNAL TREATMENT
The following unit prices have been used for the internal measures:
Power 0.60 2/kwh
Heat 3.50 $/10« cal
Maintenance: 2.5% of capital cost, annually
296
-------
Costs of heat exchangers, storage tanks, pumps and pipes are estimated
according to Chemical Engineering, March 24, 1969, issue and updated to
August 1971 price levels.
It should be recognized that costs of internal process modifications may
vary greatly from mill to mill, and that cost of internal improvements
should be evaluated upon consideration of local conditions.
Spill and Evaporator Boilout Storage
Chemical spills are collected, pumped to storage and fed into the black
liquor evaporator plant. Fiber spills from floor drains are recovered
in a save-all and returned to the pulp line.
Investment costs for 907 kkg/day (1000 tons/day) Kraft Mill are:
$1000
Overdesign of evaporation plant (installation
of one additional effect) $1150
Chemicals storage tank (260000 gal) 100
Fiber storage tank (8000 gal) 5
Saveall 150
Pumps, pipes, valves U50
Instrumentation 100
Total $2000
Operating costs will be zero since value of recovered chemicals and
fibers will cover operating expenses. However, value of recovered
fibers and chemicals will not cover capital expenses.
NSSC-Na Copeland Recovery Process
Assumed process parameters and operating conditions of the copeland installatic
Pulping Process NSSC
Pulp Production, ADTPD 200
Yield, % 75
Washing efficiency, % 90
Chemical Requirements, LB/ton
Na2C03 UHO
Sulfur 95
Weak liquor concentration, % solids 10
Heat value on weak red liquor BTU/lb 5600
Waste liquor feed (1) 263 GPM 70.U t/hour
Cone, liquor product (2) 91 GPM 27.3 t/hour
Evaporation capacity 1 H20/hr 50
Steam requirements, TGPS/hr (3) 20
Air blower horsepower, HP
Connected 900
Operating 675
Process power requirements, kw
Connected 350
Operating 275
297
-------
(1) Sp. Gr.: 1.07, 10X solids
(2) Sp. Gr.: 1.20, 35X solids
(3) Triple-effect evaporation
Operational utilities required for application of Container -
Copeland Process:
Low pressure steam, ton/hr 20
High pressure steam, ton/hr 5
Electric Power, kw 780
Operating Cost
Steam 2.0U DOL/T steam, 8400 hours/year U29000 $/yr
Electric power (0.6 c/kwh, 8100 hours/year) 39000 $/yr
TOTAL U68000
Investment Cost Estimate
$1000
Evaporation plan (triple effect) a80
Liquor burning and chemical recovery 1,100
Feedwater treatment 100
Buildings (27 US DOL/cu ft) 280
Planning, Design, Etc. _ 10
TOTAL 2,060
(The cost does not include compressor station, electrical
supply station, outside piping, and turbines.)
Land Disposal of Junk Materials
The cost has been calculated on the basis of an external trans-
portation contract, and no capital cost has been assumed, The
cost of transportation has been estimated to 20 cent/ton-mile,
and cost of disposal to $1.5/ton. Transportation distance has
been taken to 10 miles. Amounts of junk materials are as shown
in flow diagrams, or:
For the paperboard from waste paper mill:
3 ton junk materials a day
3 ton/day (20 cent x 10 miles + 150 cent/ton) =
1050 cent/d
Paper Machine Controls
High pressure self cleaning, low volume showers for paper machine
and press water filter for removing felt hairs.
298
-------
The following paper machine widths have been assumed:
-1000 tons/day liner board machine 28 feet
-750 tons/day liner board machine 21 feet
-250 tons/day corrugated board machine 14 feet
-100 tons/day wastepaper board machine 14 feet
Capital cost has been calculated to 14 feet width and then
converted to other widths by using a liner factor.
Cost for each unit:
-4 shower pipes It feet 12,000
-2 pumps (10 kw) 2,000
-1 smith screens 1,000
-4 water saveall pans 3,000
-2 hair screens, smith 1,000
-tank, piping, hoses 4,000
-spares 1,000
-design, instrumentation,
electricity, installation, etc. ll^OOQ
TOTAL $35,000
The cost of this item for a 14 foot corrugated board machine:
Wire part 35,000
Press part 35,000
Cylinder forms 35,000
105,000
For kraft liner machines:
1000 tons/day 750 tons/day
Wire part 55,000 45,000
Press part 55^000 45^000
110,000 90,000
Spill Control
By spills it is are meant releases of wood fibers and/or process
additions to those which are "normal" for the process. The
release of the "normal" pollutant load for a process de-
pends upon the process design and equipment used, and
is therefore reasonably well defined or deterministic
in nature. The spills are caused by "accidents" or
mechanical failures in the production facilities and
are as such probabilistic in nature.
The accidental spills are in general of short duration and
299
-------
usually have a fiber and/or concentration of chemical sub-
stances which are several times those of the normal mill
effluents (1). Another undesirable property associated with
accidental spills is that they might not be intercepted
by the waste water collection system that finds its way into
the storm sewers and therefore bypasses all treatment waters.
The main sources of accidental losses are:
a) leaks and overflows from storage tanks
b) leaks and spills resulting from repairs, system
changes and mistakes in departments handling
strong liquor, and
c) overflows from screens and filters in departments
handling fiber
Controls of spills can be done by connecting overflow lines
to holding tanks equipped with pumps, a procedure which returns chemicals
to storage or to the recovery system, and fibers to the stock
chest.
Cost of spill control is based on systems shown schematically
in Figure 1, Appendix III.
Costs of spill controls are lump sums as shown in the cost
summary. These costs include construction costs and mechan-
ical and electrical equipment as shown in Figure 1, Appendix III.
Large Spills
Large accidental losses caused by mechanical failures can
be prevented by an effective control system, e.g., conduc-
tivity measurements in the waste water lines. As these losses
might render the effluent unsuitable for treatment, an
emergency spill basin is constructed to intercept these
wastes. The spill basin content is pumped back to the treatment
process at a rate which does not "upset" the treatment process.
Construction cost of the spill basin is based on a system
which is shown schematically in Figure 2, Appendix III.
Design Criteria for Spill Basin:
Volume: 12 hours of average flow
Pump Capacity: Basin volume returned to treatment
process in 12 hours at 30 feet head.
Basin: Earthen construction with 12 foot depth
300
-------
^H
.
V
-» —
Storage
Tank
mmmmmmm
t
To Recovery
\
Holding Tank
a) Control Of Chemical Spills And Losses
Stock
Storage
Holding Tank
b) Control Of Fiber Containing Spills
To Process
Emergency Overflow To
Treatment Plant
To Process
Emergency overflow to
treatment plant
Figure 1
Spill Control Installations
301
-------
Process Effluent
Sewer
Spill Basin
Figure 2 Spill Basin and Controls
To Treatment
Process
302
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Sewers
Plant Sewers
Plant sewers are defined as the gravity flow type conveyance facilities
within the boundaries of the treatment plant. These may be both closed
conduits and open channels. The capital costs of these items are
included under the respective treatment plant components.
Annual operation and maintenance costs of in-plant sewers have been
taken at a flat 0.50% of the estimated construction cost with no
differentiation between materials of construction, except as reflected
in the construction cost.
Interceptor Sewers
Interceptor sewers are defined as the conveyance facilities which
connect the mill to the treatment plant and the treatment plant to the
outfall system. Thus, they may vary from being insignificant in a
situation where land is available adjacent to the mill, whereas they may
amount to a large percentage of the treatment plant cost where long
interceptor sewers are required. For this reason no interceptor sewers
are included in this study.
Submarine Outfalls
The costs of these facilities are based on moderately severe
oceanographic conditions. Costs include pipe, excavation, laying and
jointing, backfill where necessary, provision of protection
against scour, a straight diffuser section at outlet and with multiple
outlets for efficient initial dilution, testing, and cleanup.
Annual operation and maintenance costs of outfall systems have been
taken at a flat 0.50X of the estimated construction cost.
Land Requirements and Costs
Land Requirements
A site suitable for an effluent treatment facility should have the
following properties:
- should be within a reasonable distance from the production
facilities so that long and expensive interceptor sewers
are eliminated.
- should be far enough from the production facilities so that
their expansion possibilities are not hampered.
303
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- should be at a suitable elevation relative to the production
facilities so that pumping costs are minimized, and ideally
allow for gravity flow through all treatment units.
- should allow for orderly future treatment plant expansion on land
which can be purchased at a reasonable price and with adequate
soil properties.
The two major factors affecting the area requirements for external waste
water treatment are the type of secondary treatment and the type of
sludge disposal. The approximate land requirements for the most
commonly used secondary treatment methods used in the pulp and paper
industry are shown below.
Land Requirement for different secondary treatment
methods
Treatment Method Land Requirements - Acre/MGD
Natural Stabilization 40.0
Aerated Stabilization 2.0
Activated Sludge O.OU
Land required for ultimate solids disposal depends on the
sludge quantities generated, moisture content, ash content
and method of placement.
Land requirement for different ultimate sludge
disposal methods (Disposed effluent at 12 feet
depth)
Disposal Condition Land Requirements
sq ft / ton dry solids
Thickened clarifier underflow, 5% solids 53.0
Centrifuge cake, 20X solids 16.5
Pressed cake, 35X solids 11.6
Incineration, 3% ash 0.15
Incineration, 12* ash 0.60
Land Costs
The value of land is often difficult to establish. Depending upon land
availability and alternate land use, the land cost might vary from $1.00
per square foot or more down to only a few cents per square foot. For
the purpose of this study a land cost selected was $4,000 per acre.
EXTERNAL TREATMENT
304
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Pretreatment
Pretreatmervt consists of screening only for all alternatives considered
in this report.
Total effluents from all mills considered in this study usually lose
coarse material in the form of chips, bark, wet strength paper, etc., in
quantities that require screening to avoid plugging of sludge lines and
escape of floating objects over overflow weirs.
Although vibrating screens have proven satisfactory when the flows are
small (2-4 MGD), traveling screens with one inch openings have been
recommended (2) and are used for all mills included in this study.
Design Criteria: Type: Travelling bar screens
Design Floy: Average daily
Bar Spacing: 1 inch
Capital Cost in $1,000 =
11 + .27 x Q + 7.64 X Q**.625
where: Q = average daily flow in MGD
(cost information from numerous individual
installations was also considered in all cases)
Capital cost and annual operation and maintenance costs for raw waste
screening are shown graphically in Figure 3, Appendix III.
Primary Treatment
Primary treatment is most economically done when all fibers containing
wastes are mixed before treatment. Besides the fact that large units
give lesser treatment costs than a series of smaller units, mixed
effluents generally also have improved settling characteristics, thus
decreasing the total treatment unit requirements. Internal fiber
recovery is assumed done to the maximum economic justifiable degree, so
that no external fiber recovery for reuse is considered in the treatment
process design.
Three unit operations for suspended solids separation have been
considered. These are:
a) settling ponds
b) mechanical clarifiers
c) dissolved air flotation
Settling Ponds - Design Criteria:
Construction: earthen construction, concrete inlet and outlet structures
Detention time: 24 hours
305
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Water depth: 12 feet
Sludge removal: manual
Cost Functions:
Capital cost in $1000 = 27.3 x**0.75
where: V = pond volume in million gallons
This construction cost function is based on work bin Reference (3). The
construction cost, which includes plant sewers, and all diversion -
inflow-, and outflow- structures, but excludes land costs, is shown
graphically in Figure U, Appendix III. The function is "verified" by
plotting data from the field survey phase on the same figure.
Operation Costs:
The operation cost of sedimentation ponds consists mainly of sludge
dredging and disposal which was estimated to cost $6.50 per ton of dry
solids removed.
Annual maintenance was estimated to be 1X of capital cost.
Primary Clarifiers
Construction: Circular heavy duty plow type rotary sludge scraper, scum
collection and removal facilities.
Overflow rate: 700 gpd/ft**2 (4) Widewater depth: 15 feet
Capital cost in $1000 (3) =
62x((1.5 - O.OOlQx1000./OR)**0.60
where: Q = flow in MGD
OR = overflow rate in gpd/ft**2
The construction costs include all mechanical and electrical equipment,
instrumentation, installation, and sludge pumps and plant sewers. Land
costs are not included. This cost of function is shown graphically in
Figure 5, Appendix III and includes data from the field survey phase of
the project.
Secondary Treatment
BOD removal, i.e. secondary treatment, in the pulp and paper industry is
usually done by a biological process. However, no single design of any
biological treatment process is applicable to all pulp and paper mill
effluents. Four different biological units in various combinations have
been considered in this report: a) biological filters, b) natural
oxidation ponds, c) aerated lagoons (or aerated stabilization basins) ,
and d) activated sludge treatment units.
Biological Filters
307
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In spite of a serious attempt to use biological filters, they have not
found widespread use in the pulp and paper industry. According to
Reference (6) , this fact is due to plugging problems and BOD5 loadings
which prohibit high efficiency removals. A summary (6) on tickling
filter performance shows BOD removals, ranging from 25 to 52X. With
these removal degrees it can be concluded that trickling filters can
only be used successfully as a roughing device prior to additional
treatment. Trickling filters are, therefore, not considered further in
this study.
Natural Oxidation Ponds
From a cost standpoint, this treatment method can only be considered
when large areas of "inexpensive" land are available. Another factor
limiting their use in the pulp and paper industry is that the effluent
colors are usually higher than those of sanitary wastes and,
consequently, the growth of the algae population might be prohibited or
reduced, resulting in lesser oxygen quantities available for the
biochemical process. However, for mills located in the South, where
climatic conditions are appropriate for photosynthetic activity
throughout the year and large land areas are often available, this
method is reasonably effective.
Decomposition products from the biological mass will accumulate on the
sludge bottom and may have to be removed periodically.
Design criteria:
Construction: earthen, unlined, concrete inlet and outlet structures
Loading rate: 50 Ib BOD/acre/day (7)
Liquid depth: 5 feet (7)
BOD removal: 85X
Cost functions: Capital cost in $1000 (3) = 62800 x A**0.74
where A = pond area in acres
The cost function includes all material and labor required for all earth
moving, bank stabilization, concrete work and plant sewers. Cost of
land is not included.
Operation cost was considered independent of pond size and estimated to
be $6000 annually.
Since the rate of metabolism is low and the detention time is long, it
is assumed that the biomass will lyse and no nutrient addition is
assumed necessary.
Maintenance cost is estimated to be 0.75X of the capital cost annually.
Aerated Lagoons
The aerated lagoon system used for the costing basis consists of two
aerated cells in series as shown in Figure 6, Appendix III. This system
310
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RAW
WASTEWATEfT
PRE-
TREATMENT
1
h
NUTRIENT
ADDITION
PRIMARY
TREATMENT
i
r ^
*•
FIRST
AERATION
CELL
DET. TIME
0.3^0 DYS
hi
^
SECOND
AERATION
CELL
OET. TIME
1.5- 10 DYS
K
P
SECONDARY
CLARIFIER
(OPTIONAL)
TREATED
^
EFFLUENT
I
SCREENINGS,
ETC.
SLUDGE
SLUDGE
Figure
Aerated Lagoon Treatment Plant
311
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was chosen because it usually gives better overall performance at lower
land requirements than the conventional single cell does. The aeration
system consists of mechanical surface turbine aerators. Minimum power
levels are assigned to ensure adequate mixing and oxygen distribution.
Nutrients are added in proportions to biological mass production and
solids wasted in the effluent. It is assumed that the biomass will lyse
and release nutrients to a large degree in the second cell, so that
nutrient addition is required only in the first cell. Nutrients have
been added in quantities as determined by Reference #8 in that H pounds
of nitrogen and 0.6 pounds of phosphorus should be provided per 100
pounds of BOD removed. Nutrient content in the influents are included
in these values.
Design Criteria: Aeration Cells
Construction:
earthen construction, stabilized banks, lined for
seepage prevention, concrete inlet and outlet
structures, two cells in series.
Liquid depth: 15 feet
Nutrient addition:
U pounds of nitrogen and 0.6 pounds of phosphorus
per every 100 pounds of BOD removed. Influent
nutrients are subtracted from these values.
Aerators:
Type: mechanical surface turbine aerators
Minimum power levels: 20 HP/MG in first cell (9)
6 HP/MG in second cell (9)
Secondary clarifiers:
Construction: Circular, concrete tanks, plow type rotary sludge
scraper
Overflow rate: 600 gpd/ft**2
Sidewater depth: 15 feet
Cost functions: Capital Costs in $1000:
Aeration cells (10) = 62.8 x A**0.7U
where A = total cell area in acres
Aerators (10) = 1.13 x HP**0.80
where HP = total horsepower installation
Secondary clarifiers (3) = 62.*((1.5-0.001Q)Q x 1000/QR)**0.60
312
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where Q = flow in MGD
QR = overflow rate in gpd/ft**2
Operating and Maintenance Costs:
Aeration Cells:
Annual aeration cell maintenance costs were taken to be 1.0 percent
of capital costs (10).
Nutrient costs were calculated on the basis of $250 per ton of
nitrogen and $380 per ton of phosphorus.
Sludge removal cost was based on the assumption that 0.2 ton of
sludge settles to the aeration basin bottom per ton of BOD removed
and that the unit price of sludge removal is $7.50/ton. This sludge
accumulation rate is representative of existing field installations
for aerated lagoons.
Operation cost estimates were based on work in Reference (11):
Annual cost: 18.5 x Q**0.25
where Q = average daily flow in MGD
Aerators:
Annual maintenance costs for the aerators were taken to be 10% of
installed aerator cost (10). Power cost used 1.1 cents/kwh.
Secondary Clarifiers:
Annual operation and maintenance costs were obtained from work in
Reference (5) and are:
1360 Q + 3537 x Q**0.5
Q = average daily flow in MGD
Activated sludge
All costs for activated sludge treatment considered in this study
are for completely mixed systems, and with biological reaction and
oxygen utilization rates representative of the particular effluents
undergoing treatment. The completely mixed system was selected
because of its ability to handle surges of organic loads and slugs
of toxicants. The activated sludge plant used for the costing basis
is shown in Figure 7, Appendix III.
Design Criteria:
Aeration Tank:
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Raw Waste Water
or
Primary Treatment
AERATION
• TANK
DETEN. TIME
1-5 HRS.
Recycled
Sludge
Secondary
Effluent
Figure 7 Completely Mixed Activated Sludge System
314
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Construction: reinforced concrete with pier mounted surface
aerators.
Liquid Depth: 15 feet
Nutrient addition: 4 pounds of nitrogen and 0.6 pounds of
phosphorous per every 100 pounds of BOD
removed. Influent nutrients are subtracted
from these values.
Aerators: Type: mechanical surface aerators
Secondary Clarifiers:
Construction: circular concrete tanks with rotary suction
type sludge collector
Sidewater depth: 15 feet
Cost Functions: Capital costs in $1000
Aeration tank (3) = 225 x V**0.71
where V = tank volume in million gallons
Aerators (3) = 1.75 x HP**0.81
where HP = total horsepower installed
Secondary Clarifiers (3) = 62.* (1.5-0.002Q)Q*1000.OR)**0.60
where Q = flow in MGD, including recycle
overflow rate in gpd/ft**2
Sludge recycle pumps (3) = 5.36 + 1.66 x Q
where Q = average daily flow in MG
Operation and Maintenance Costs
Cost of operation and maintenance of activated sludge system has been
calculated using a cost function developed in Reference 5. This cost
function includes operation and maintenance of aeration basins,
aerators, final sedimentation tanks and sludge return pumps:
Operation cost (tf/1000 gal) = R x (3.40 «• H.95/v**0.5
where V= basin volume in million gallons
R=retention time in days
The breakdown between operation and maintenance is 60% and HOX,
respectively (10).
315
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Power cost is calculated from the net horsepower requirements at
1. U/kwh.
Nutrient cost are calculated on the basis of $250 per ton of sludge and
$380 per ton of phosphorus.
Color Removal
Basis: "minimum lime" process
Costs include addition of lime kiln capacity, mixing eqmt.,
lime clarifier w/associated lime sludge thickening and
handling, necessary pumps, piping, instrumentation and
auxiliaries.
1000 T/D Unbleached Kraft Mill
capital: $1,800,000 + 35% engr.
legal and contingency = $2t43gzOOC
operating (maint., spares, power,
make-up chemicals, labor,
insurance and taxes) = $ 297,50C/yr
add: 15% of 2,430,000 interest + = 361.500
depr.
total annual cost = $ 662,000
less: energy cost at 10% of
297,500 = 120.000
annual cost less energy = $ 542,000
$542tOOO = $1.50/ton less energy
1000 x 350
T/D Days/Yr
120,000 = ^35/ton energy
1000 x 350 1.85/ton total
1000 T/D Cross-Recovery NSSC-Kraft Mill
capital: $1,500,000 + 35% = 12x025^000
operating (same basis as above) =
$ 280,000/yr
add: 15% of 2,025,000 depr+int. = 304^^00
total annual cost = $ 584,000
less: energy cost at 40% of
280,000 = 112T000
$ 472,000
$472,000 = $1.35/ton less energy
1000 x 350
112^000 = _0-32/ton energy
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1000 x 350 $1.67/ton total
Sodium Base NSSC-250 T/D
20C T/D mill (i.e. 250 T/D w/50 T/D wastepaper)
1 Capital cost $250,000 turnkey, 100GPM =
150,000 gal/day
Annual Costs
depr. + interest at 15% of $250,000 = $37,500
operating cost incl. energy
150.000 gal x 35C days x $0.95 2 = $50,000
day yr 1000 gal
increase by 40* to reflect higher unit costs
in 150,COO gal/day unit of w/500,000 gal/day
in 2.
$50,000 x l.<*0 = 10x000
total annual cost = $107,500
less: elec. power costs
HP = (IQOgpm) (600psi) = 60 HP for R.O
171U (,60)
+ est. for transfer pumps= 20_HP
total est. HP = 80 HP = 60kw
60kw $.011 x 2J*_hr x 350 days = power cpst=
kw-hr day yr 5,500
total annual cost
less power = $102^000
Cost Per Ton
$102,000 = $1.50 per ton (not
200T/D x 350 days/yr incl. power)
$5^500 = _£j.Z9 per ton (power)
200x350 $2.29 total cost per
ton
Ammonia Base - 200T/D+50T/D Waste Paper =25CT/D
No data available.
Assume same as sodium base.
317
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Mixed Media (Multi-Media) Filtration for Suspended Solids^Remoyal
1000 T/D Unbleached Kraft Mill
capital: $240,000 + 35% =
operating $123,000
add: 15X of 325,000 for int.+depr. = _ 18.500
total annual cost = $141,500
less: 35X of 123,000 for energy = __ 43,000
annual cost less energy = $ 98,500
198^,5 00 _ = $0.28/ton less energy
1000x350
T/D days/yr
_43X000_ = P_..12/ton
1000x350 $ .UO/ton total
1000 T/D Cross-Recovery Mill
capital: $210,000 * 35X = $284.000
operating $100,000
add: 15% of 284,000 (int.+depr. ) = __ 43,000
total annual cost = $143,000
less: energy at 35% of 100,000 = __ 35^000
annual cost less energy = $108,000
$108^000 = $.31/ton less energy
1000x350
35,000 = _.10_/ton energy
1000x350 $741/ton total
250 T/D NSSOSodium Mill
capital: $100,000 + 35% = $135^000
operating 37,000
add: 15% of 135,000 (int+depr.) = __ 20^000
total annual cost = $~57,000
less: energy at 35X of 37,000 = _ 13 f OOP
annual cost less energy = $ 44,000
44.000 = $.50/ton less energy
250x350
13 f 000 = _..15/ton energy
250x350 $.65/ton total
318
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capital: $120,000 + 35% = $162.000
operating 73,500
add: 15% of 162,000 = 21.000
total annual cost = $ 97,500
less: energy at 35% of 73,000 = 26,000
annual cost less energy = $71,500
$71,500 = $.82/ton less energy
250x350
26,000 = .30/ton energy
250x350 $1.10/ton total
Paperboard from Waste Paper 100/TD
capital: $75,000 + 35% = $101*000
operating $ 12,300
add: 15% of 101,000 = 15^000
total annual cost = $~27,300
less: energy at 35% of 12,300 = U^300
$ 23,000
23^000 = $0.76/ton less energy
100x300
U.300 = O.ltl/ton energy
100x300 $0.90/ton total
SLUDGE DEWATERING
The sludges drawn from the primary and secondary clarifiers require
dewatering prior to final disposal. A large number of unit operations
are available for this purpose, from which the specific selection
depends upon local conditions like sludge characteristics, proportion of
primary and secondary sludges, distance to ultimate disposal site, and
ultimate disposal considerations.
The units operations considered in this study are sludge settlings
ponds, gravity thickeners, vacuum filters centrifuges and sludge
presses. The selected sludge dewatering process might consist of one or
more sludge dewatering unit operations.
The dewatered sludge solids are usually disposed of either by
landfilling or incineration, according to local conditions and the level
of technology required. Sludge disposal by landfilling might give very
satisfactory solutions provided a suitable site can be found within a
reasonable distance from the mill.
319
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Possible harmful effects from landfilling are groundwater pollution by
leaching of chemical constituents or decomposition products and erosion
by precipitation. Thus, both soil conditions and climate must be
suitable to make sludge disposal by landfilling successful, or the
required site work might result in a very expensive solution.
Provided air pollution requirements are met, sludge incineration is,
from an environmental point of view, a very satisfactory solution, since
only inert ashes need to be disposed of. Although the solution is
usually quite expensive, especially for small installations, lack of
other solutions might make it the only alternative.
Cost of sludge dewatering and disposal commonly accounts for 30-50X of
the total treatment cost.
Cost Functions:
Sludge dewatering ponds: Capital cost in $1000 (3) = 125 x V**0.70
where V = volume in MG
The operation cost of sludge ponds consists mainly of sludge dredging
and disposal which was estimated to cost $6.50 per ton of dry solids
removed.
Annual maintenance cost was estimated to be 1% of capital cost.
Gravity Thickeners: capital cost in $1000 (3)
= (SA)(3U.+16.5/exp (SA/13.3)
where SA = surface area in thousands of square feet
Annual operation and maintenance costs of gravity sludge thickeners were
estimated to 8* of the capital cost.
Vacuum Filters: capital costs in $1000 (12) = U.70 x A**.58
where A = filter area in square feet
Operating and maintenance cost for vacuum filtration was based on the
following (3):
Labor: 0.5 man-hours per filter hour 3 $5.25 per hour
Power cost: 0.15 HP per square foot of filter 3)1.10 <*/kwh
Chemicals: $10.00 per dry ton for waste activated sludge, and
$1.00 per dry ton for primary sludges
Maintenance: 5% of capital cost, annually
Centrifuges: capital costs $1000 (12) = 15.65 * (HP)**0.4
where HP = total installed horsepower of the centrifuge.
Operation and maintenance costs have been calculated as follows:
Labor: 0.25 man-hours per hour of centrifuge operation 85.25 per
hour (3) .
320
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Power cost: 1.10
-------
6. Edde, H., "A Manual of Practice for Biological Waste Treatment in
the Pulp and Paper Industry," NCASI Technical Bulletin No.. 214. (1968) .
7. £ost of Clean Watert Industrial Waste Profile No^ 3, GWQA, U.S.
Department of the Interior (November 1967).
8. Helmers, E. N., J. D. Frame, A. F. Greenberg, and C. N. Sawyer,
"Nutritional Requirements in the Biological Stabilization of Industrial
Wastes," Sewage and Industrial Wastes, ND 23, Vol. 7 (1951) p. 884.
9. Eckenfelder, W. E., and D. L. Ford, Water Pollution Contrgl-
Experimental Procedures for Process Design. Pemberton Press, Austin,
Texa s.
10. EKONO, Study of Pulp and Paper Industry's Effluent Treatment^ A
Ssport Prepared for the Food and Agriculture Organization of the United
Nations. Rome, Italy, 1972. ~ ~
11. Development of Operator Training Materials, Prepared by Environmental
Science Services Corp., Stanford, Conn., under the direction of W. W.
Eckenfelder, Jr. for FWQA (August 1968).
12. Quirk, T. P., "Application of Computerized Analysis to Comparative
Costs of Sludge Dewatering by Vacuum Filtration and Centrifuge," Proc.t
23rd Ind. Waste Conf., Purdue University 1968, pp. 691-709.
Supplemental References
1) Draft of Pulp Mill In-Plant Control of Dissolved Organic Waste
Products for the U.S. Enviromental Protection Agency, Contract #68-01-
0765, May 1973, by EKONO Consulting Engineers.
2) Advanced Pollution Abatement Technology in the PujL£ and Paper
Industry, prepared for OECD, Paris, France, General Distribution,
February 28, 1973.
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APPENDIX IV
Exhibit 1
PRELIMINARY MILL SURVEY FORMAT
Information to be determined prior to mill survey.
1. PRE-VISIT INFORMATION - Obtain information describing the plant
prior to the reconnaissance survey. This could include magazine
articles describing the facilities, data or drawings furnished by the
mill, NPDES data, or any other pertinent information available. This
will enable us to get familiar with the mill before we meet with the
mill personnel.
2. EVALUATION OF EXISTING DATA - Check the availability of existing
data that the mill will make available for our inspection.
Included in this should be any drawings of the inplant or external
treatment facilities such as:
a. Layouts and sewer locations
b. Flow diagrams of treatment facilities
c. Flow diagrams of mill process areas
d. Water balance
e. Material balances
3. INITIAL MEETING - Establish what procedures will be required of us
during the sampling survey. For example, are there any areas of the
mill off limits or will the mill want someone with us at all times?
What safety requirements must we follow? Do we need safety shoes,
life preservers, hard hats, respirators, etc.? Can the mill supply
these?
4. INSPECTION OF MILL - In inspecting the various process areas of the
mill, we should identify the following:
a. Location of individual discharges to the process sewers.
b. Relative quality and type of individual discharges, i.e.,
clean, cooling water, contaminated, etc.
c. Types of sewers, i.e., open, closed, and direction of flow.
d. Location of existing flow measurement and sampling points and
type of equipment in use.
e. Tentative locations of additional sampling and gauging points.
323
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Where possible, an estimation of the average flow and possible
peak conditions will be indicated. Upstream conditions and
sewer characteristics will be inspected to ascertain that no
flooding or other problems will be encountered during measure-
ment.
f. Methods and procedures in use to prevent or intercept strong
spills.
g. Relative amount of process water reuse and adequacy of exist-
ing information such as flow diagrams to explain and document
the extent, methods, and equipment required for reuse.
5. INSPECTION OF EFFLUENT TREATMENT FACILITIES - In addition to loca-
tion of existing flow measurement and sampling points we should evaluate
the need for additional points and any special equipment needed. Sam-
pling points should be available at the following locations:
a. Primary influent
b. Primary effluent
c. Primary sludge
d. Secondary effluent
e. Secondary sludge (if any)
f. Chemical feed systems
g. Sludge disposal
h. Additional treatment facilities
6. LABORATORY FACILITIES - A complete check of the procedures used by
the mill in running its chemical and biological tests should be made by
the plant chemist or other responsible party.
Determine whether the mill will allow us to use its lab and/or personnel
during the survey. If the mill will allow us to use its facilities, a
complete list of equipment available should be made and a list of
supplies needed to perform the various tests.
If we can not use the mill's lab, we must determine where we intend to
have the samples tested and make the appropriate arrangements.
7. REVIEW INFORMATION AVAILABLE ON FRESH WATER USED AND WHERE USED -
a; Process
b. Sanitary
c. Cooling water
d. Other
Review records showing quantity and quality of fresh water and flow
measurement device used.
8. REVIEW INFORMATION AVAILABLE ON THE WASTE WATER DISCHARGE FROM THE
POWER PLANT -
324
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a. Determine water treatment facilities employed
b. Facilities used on water discharge
c. Frequency of waste discharges
d. Quality of discharge
9. COST INFORMATION - Determine or have the mill get for us (if they
will) any information on the cost of the internal and external treat-
ment facilities. This should include both capital and operating cost
for the facilities, preferably for a number of years. The method used
by the mill to finance the facilities and the number of years used to
write the expense off would be useful.
If possible the cost data should be gotten by area such as internal
treatment, primary, secondary, etc. Operating costs should include
labor, maintenance, chemicals, utilities, hauling, supplies, and any
other costs available from the mill.
10. TIME CONSIDERATIONS - Obtain any available information on the
following:
a. Time required to design the facility including the preliminary
study and final design.
b. Time to construct the facility.
c. Was construction bid after completion of engineering or done
turn-key?
d. What were delivery times for major pieces of equipment —
both internal and external?
e. What delays were encountered in getting approval by the various
regulatory agencies?
Determine the availability of any schedules, CPM or Pert charts for the
engineering dr construction.
325
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Exhibit 2
Verification Program
DETAILED INSTRUCTIONS FOR FIELD SURVEY TEAMS
A. Data Collection
The enclosed material is prepared for the guidance of field sampling and
verification crews following the preliminary Mill Reconnaissance Survey.
It is expected that these verification studies will follow along similar
lines at all field survey sites, therefore, it is intended that these
procedures be followed as closely as possible in order to provide uni-
formity to the verification program. Where mill conditions are unique,
adjustments in program operation may be necessary. If such conditions
are found, a justification for the adjustment in method should be pre-
pared, explaining the reasons for the deviations.
The material that follows is pertinent to a specific plant in that it
identifies specific sampling locations there. It is expected that other
plant sampling locations will be identified in similar fashion and the
sampling and analytical emphasis will be placed on those locations that
will have the greatest influence in the verification process.
In conjunction with the verification program it is expected that each
plant will have in its files records of its wastewater control opera-
tions, including daily analyses of the pertinent parameters, such as
BOD, SS VSS, pH, flows, production information, etc. Such data as is
available should be obtained for a period of at least 13 months (overlap
to account for end of year shutdown and startup) including not only
daily summary information but the laboratory bench sheets wherever
possible. Also, during the field visit every opportunity should be
taken to arrange for split samples between the plant lab and the field
operation as well as to exchange analytical results on locations that
are being sampled and analysed separately. These data will be most
valuable in the verification process to establish laboratory bias, if
any, of the results reported by the plant in question.
We have purposely selected the hourly grab sample method of sample and
composite preparation of the important waste stream components in order
to circumvent any errors that may be due to design or faulty operation
of any automatic samplers or other sample collection devices. In
reference to sampling of process streams within the plant it is of
utmost importance that every effort be made to obtain samples from the
following process wastewaters in the pulp mill and paper mill areas:
Pulp Mill
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wood handling and barking
digester and washings
causticizing
recovery
Paper MJL 11
wet end
dry end - with and without coating applications.
Integrated sampling programs are preferred, as outlined for the major
wastewater and treatment units; however, random grab samples will be
acceptable if the sampling locations are not amenable to a more precise
technique. In any case, every effort should be made to accommodate the
sampling to flow or other critical variations within the process under
study.
The analytical program exemplified by the attached pages described that
which is under way at a specific plant. Each mill study should be
programed to carry out these analyses on the significant waste streams
in accordance with parameters and frequencies listed. The locations at
which the analyses are to be performed will determine the sample
preservation method. It is recommended that all analyses be performed
with minimum delay following collection.
SAMPLING AND ANALYSES PROGRAM
I. Identify Sampling Locations as Exemplified below:
Station #
1. Process Water - raw
2. Heavy Liquor - raw
3. Clarifier inflow - raw
6. Clarifier Effluent - primary
Sample stations 1, 2, 3, and 6 once/hr. Measure Temp.,
Measure/record flow.
9. Final Effluent
Sample this station once/hr, when flowing. Measure Temp. °C,
when flowing. Measure/record flow, when flowing.
H. Ash Pond overflow
5. Color Pond overflow
7. Aeration Pond overflow
8. Stabilization Pond overflow
10. Non Process overflow
11. Raw Intake
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Sample stations H, 5, 7, 8, 1C, and 11 once every 2 hrs.
Measure/record Temp. Measure/record Flow, where measurable.
12. Clarifier Underflow
Sample at the beginning and end of the underflow pumping
operation.
13. Process Streams
Sample as often as in-process changes warrant.
II. SAMPLING INSTRUCTIONS
1. Fill sample collector completely; then pour out.
2. Fill again. Measure temperature immediately.
3. Stir rapidly; then pour off about 1 liter into sample bottle.
H. Mark (tag bottle) with Station f, time, flow, and temp.
5. Seal bottle, place in cooler, deliver to lab.
6. Keep sample in cooler until ready for compositing.
7. After returning from a sample run, enter the data collected
on the log sheet.
III. COMPOSITING INSTRUCTIONS
1. Arrange the hourly collections per sample station in the order
of increasing flow rate.
2. Determine the volumetric ratio of each sample by dividing the
lowest flow rate into each succeeding flow rate, i.e., flow
rate 100 G/M, 110, 120, 150, 180, 200, etc. Divide 100 into
each succeeding number to get ratios 1.1, 1.2, 1.5, 1.8, 2.0,
etc.
3. Stir the sample well. Measure the amount to be removed, i.e.,
500 Ml base x 1.2 = 600 Ml into a grad. cylinder. Transfer
into the compositing bottle for the sample station.
4. Attach tag giving number of composites and volume of each as
well as other pertinent data, i.e., station number, date,
period of composite.
5. Mix well. Remove appropriate volume for shipment back to the
main lab. The remainder will be used for analysis at the site.
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IV.. ANALYSES TO BE PERFORMED
Location
_- for
Analysis Test
STATION
6 789 10 11 12 13
PRIMARY SECONDARY SOLIDS
B. C. D. etc.
00
ro
ID
F
F
F
F
F/L
F/L
F
L
BOD5
PH
Suspended
Solids
V. SS.
Dissolved
Solids
Ash
Color
Metals -
D D
D D
D D
D D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
0
0
0
D
D
D
D
0
—
D*
D*
D*
(Fe. MN, Nl
Cr, Pb, Hg,
Cu, Zn)
Total N -
(Kjeldahl +
D*-
D*-
No2,No3)
L Total P.
F/L Sp. Cond. D
T T
T T
D D
Key to Number Codes
1 - Process Sewer
2 - Heavy Liquor
3 - Clarifier in
4 - Ash Pond Out
5 - Color Pond out
6 - Clarifier out
7 - Aeration Pont out
8 - Stabilization Pond
9 - Final Effluent
10 - Non-Process Sewer
11 - Raw Water Intake
12 - Clarifier Underflow
13 - Process Stream
A,B,C,D, etc refers
to location within
process
Key to Letter Codes
D - refers to daily composite
T - refers to total composite
0 - refers to daily composite, run one tine only
F - refers to Field analysis
L - refers to Home Laboratory analysis
D*- combine random grab samples If programmed
sampling cannot be carried out.
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V. METHODS TO BE USED FOR MILLS SURVEYS
Color^ NCASI Method
1. Measure 200 ml sample and adjust pH to 7.6 by adding 1. N NaOH or
1. N H2S04, while pH Meter is in sample.
2. Filter sample through 0.8 micron membrane.
3. Measure absorbance at U65 NM.
U. Read Color value from standard curve, prepared from pt. co. stan~
dard.
Suspended Solids/Volatile Suspended Solids
Use 5.5cm fiberglass filter which has been heat treated and weighed
prior to use.
Metals Determinations
To preserve samples for metals analyses, add 5 ml reagent grade HN03
per liter of sample. Preserve at least 1 liter of each sample that
is to have metals analyses. Also, save a 100 ml sample of the con-
centrated nitric acid used for preserving the metals samples. This
will be used to establish a reagent blank for the metals.
BODS
1. Select the appropriate dilutions (no less than two) for the sample
to be analysed.
2. Mix the composited sample well.
3. Transfer the appropriate volume with a pipette into a standard
300 ml BOD bottle.
U. Fill the BOD bottle into the neck with the dilution water; do not
overflow. Allow air bubbles to escape.
5. Measure and record initial D.O. with Probe.
6. If any water is lost after probe is removed, add dilution water so
that water level is into the neck of the BOD bottle.
7. Insert stopper carefully to avoid entrapment of air bubbles.
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8. Place bottle in incubator at 20°C + 1. Incubate 5 days + 2 hours.
9. Measure and record final D. O. with Probe.
10. Make appropriate corrections for seed and dilution water as follows:
a. Prepare 5% dilution of seed if aged primary or 50% dilution if
raw river water, following steps 3 through 9 above.
b. Calculate the D. O. equivalent of the seed plus dilution water
and record.
11. Use those dilutions that fall within the D. O. depletion limits
shown in Standard Methods p492.
12. Subtract the D. O. equivalent of the seed plus dilution water from
the final D. O. of each sample.
13. Multiply the net D. O. depletion by the dilution factor to give
the BOD value for the selected dilution.
14. a. If more than one dilution falls within the acceptable range,
report the average of the BOD's of the individual samples.
b. If all dilutions are depleted of D. O. report the highest
dilution as greater than .
c. If all depletions are less than 2 mg/1 D. O., report the lowest
dilution only.
15. Run a glocuse-glutamic standard, preferably with each day's run of
samples.
16. Run a duplicate dilution on approximately one-third of the samples
daily.
BOD Dilution Water
1. Use distilled water only as base. Check for D. O.; aerate if
necessary.
2. Check for copper with cuprethal reagent, or equivalent. This is
necessary if the dilution water is purchased, or is from a source
not previously checked for copper. Reject if Cu test is positive,
i.e., greater than 0.01 mg/1.
3. Withdraw a volume of dilution water sufficient for the day's samples.
4. Add appropriate volumes of mineral and buffer solutions. (Stan-
dard Methods p489-U91). Stir well.
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5. a. Add 2 ml seed/liter if primary effluent from municipal STP
is available.
b. If not available use raw river water (50 ml/1).
6. Check pH. Should be 7.2.
B. Data Analysis and Transmittal
1. Upon completion of each Field Survey prepare a critical analysis
of the verification program in which the following elements are considered.
An analysis of the variability of results between the plant
laboratory and the field study taking into account the split
samples, standards duplicates, etc., and the results reported
for each sample by the separate laboratories.
2. Based on your analysis, indicate the appropriate factors that need to
be applied to the available historical data that will bring these into
line with similar data being collected at other plants. Indicate how
and where each factor should be applied.
3. Transmit the raw data which were obtained during the verification
study including all analyses that were performed on all samples.
U. Transmit two copies of the 13 months of plant performance data which
are to be used to establish the performance expectations of the treatment
system being studied.
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APPENDIX V
A. TENTATIVE PROCEDURE FOR COLOR MEASUREMENT OF PULPING WASTES AND
THEIR RECEIVING WATERS - SPECTROPHOTOMETRIC METHOD.(2)
(1) INTRODUCTION
The color of pulping waste or its receiving water is considered to
be the color of the light transmitted by the waste solution after
removing the suspended material, including the pseudocolloidal
particles. It is recognized that the color characteristics of some
wastes are affected by the light reflection from the suspended
material in the wastes.
The term "color" is used herein to mean "true color"-that is, the
color of the water from which the turbidity has been removed.
(2) GENERAL DISCUSSION
(a) Principle; Color is determined by spectrophotometric
comparison of the sample with known concentrations of colored
solutions. The platinum-cobalt method of measuring color is given
as the standard method, the unit of color being that produced by 1
mg/1 platinum, in the form of chloroplatinate ion. The ratio of
cobalt to platinum may be varied to match the hue in special cases;
the proportion given below is usually satisfactory to match the
color of natural waters.
(b) Interference; Even a slight turbidity causes the measured
color to be noticeably higher than the true color; therefore, it is
necessary to remove turbidity before true color can be measured by
spectrophotometric comparison. The recommended method for removal
of turbidity is filtration through a membrane filter having a median
porosity of 0.8 microns.
The color value of a water is highly pH dependent, and invariably
increases as the pH of the water is raised. For this reason it is
necessary, when reporting a color value, to adjust the pH of all
samples to 7.6 with 1 N HCl or 1 N NaOH solution.
(c) Sampling; Samples for the color determination should be
representative and must be taken in clean glassware. The color
determination should be made within a reasonable period, as biologic
changes occurring in storage may affect the color and alter the pH
value.
(3) APPARATUS
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(a) Spectrophotometer. having absorption cells of the following
length for minimum detectable color.
Absorption cell Minimum Detectable
30 1
20 5
10 8
5 10
1 25
a narrow (10 mu or less) spectral bank and an effective operating
range from 400 to 700 mu.
(b) pH meter. for determining the sample pH.
(c) Eiitration_§v.S|iejT!» consisting of flask, vacuum source, filter
holder, and 0.8 micron porosity membrane filters.
CO PREPARATION^OF^STANDARPS
If a reliable potassium chloroplatinate standard solution cannot be
purchased from a laboratory supply house, it may be replaced by
chloroplatinic acid, which which the analyst can prepare from
metallic platinum. Commercial chloroplatinic acid should not be
used because it is very hygroscopic and therefore may vary in
platinum content. Potassium chloroplatinate is not hygroscopic.
Dissolve 1.246 g potassium chloroplatinate, K2PtC16 (equivalent to
0.500 g metallic platinum) and 1 g crystallized cobaltous chloride,
CoC12.6H2O (equivalent to about 0.25 g metallic cobalt) in distilled
water with 100 ml concentrated HC1 and dilute to 1 liter with
distilled water. This stock standard has a color of 500 units.
If potassium chloroplatinate is not available, dissolve 0.50C g pure
metallic platinum in aqua regia with the aid of heat; remove nitric
acid by repeated evaporation with fresh portions of concentrated
HC1. Dissolve this product together with 1 g crystallized cobaltous
chloride as directed above.
Prepare standards having colors of 25, 50, 100, 150, 200, and 250 by
diluting 2.5, 5.0, 10.0, 15.0, 20.0, and 25.0 ml stock color
standard with distilled water to 50 ml in stoppered volumetric
flasks. Protect these standards against evaporation and
contamination when not in use.
Transfer a suitable portion of each final solution to a 10 mm
absorption cell from a "matched set" of cells and measure the
absorbance at 465 mu. As reference use distilled water for
instrument calibration to zero absorbance.
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Construct a calibration curve by plotting absorbance values against
color units similar to the sample curve presented in Appendix V
Figure 8.
Appropriately lower color standards should be used for the
calibration curve with longer absorption cells. For example,
employing the 10 to 2C centimeter cells, use standards of 5, 10, 15,
20, 25, 50, 75 and 100 units of color, and develop the curve similar
to the appropriate cell length illustrated by the set of curves
presented in Figure 6 of the report.
(5) PROCEDURE
Preparation of sample: Select a 200 ml sample of waste or water,
adjust pH to 7.6 with HCl or NaOH as indicated in Section 2 (2). If
the overall volume change is greater than one per cent, discard
sample and start anew with stronger solutions of HCl or NaOH for the
pH adjustment. In any event, the volume change in the final sample
should be no more than one per cent.
Take a 50 ml aliquot of the pH adjusted sample and filter through a
0.8 micron porosity membrane filter pre-rinsed with distilled water.
Then transfer an appropriate portion of the filtered sample to a 1C
mm absorption cell and measure its absorbance at 465 mu, using
distilled water for the blank.
If the sample contains very high concentrations of turbidity (200 to
1000 J.T.U.) successively smaller aliquots of the sample should be
used per membrane filter. This possibility may requie filtration of
2 or 3 aliquots to accumulate sufficient sample to fill the
appropriate absorption cell. The guideline to follow in selection
of aliquot volume to filter should be based on the visual appearance
of a sudden rapid reduction in filtration rate through the filter.
This phenomenon would indicate the beginning of filter plugging, and
that possible loss of color would result on further filtration of
the sample. Filtration should be stopped immediately on this
occurrence, and the filter replaced with a clean prerinsed filter.
Prerinsing of the filter with distilled water is recommended to
prevent any change in pH resulting from use of "acid washed"
filters.
Calculate the color units in the sample by comparing the absorbance
reading with a standard curve secured by carrying out the procedure
indicated in Section H (2).
Report the color results in whole numbers and record as follows:
Color Units Record^tgNearest
1-100 1
101-500 5
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§
o
0.14
0.12
a. 10
<5.08
0.06
0.04
0.02
0.00
50
100
150
200 250
CHLOROPLATINATE - COLOR UNITS
FIGURE 8 TYPICAL CALIBRATION CURVE
300
350
10
n
ro
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A
AA
AB
An.Av.
APHA CU
API
AS
ASB
BATEA
BPCTCA
C
CD
COD
CU
DAF
g
gal/ton
gpd
gpd/sq.ft.
gpm
hp
kiloliters/kkg
kkg
APPENDIX VI
Abbreviations
Aeration
Annual Average
Alternating Basins
Annual Average
American Public Health Association Color Unit
American Paper Institute
Activated Sludge
Aerated Stabilization Basin
Best Available Technology Economically Achievable
Best Practicable Control Technology Currently Available
Clarifier
Controlled Discharge
Chemical Oxygen Demand
Color Unit
Dissolved Air Flotation
grams
Gallons per short ton
Gallons per day
Gallons per day per square foot
Gallons per minute
Horsepower
1000 Liters per metric ton
1000 Kilograms (one metric ton)
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kg/kkg
KWH
MGD, mgd
MLD
MM
Na
NCASI
NH3
NPDES
NSM
NSPS
NPDES
SM
SO
ss
ss
TF
ton
tons/day
TSS
Kilograms per 1000 kilograms
kilograms per metric ton
Kilowatt Hours
Million gallons per day
Million liters per day
Maximum Month
Sodium
National Council for Air and Stream Improvement, Inc.
Ammonia o
National Pollutant Discharge
Elimination System
Non-Standard Methods
New Source Performance Standards
Refuse Act Permit Program
Standard Methods
Storage Oxidation Pond
Suspended Solids (same as TSS)
Secondary Settling
Trickling Filter
Short ton (2000 pounds)
Short tons per day
Total Suspended Solids (same as SS)
338
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APPENDIX VII
METRIC UNITS
CONVERSION TABLE
MULTIPLY (ENGLISH UNITS)
ENGLISH UNIT ABBREVIATION
acre ac
acre - feet ac ft
British Thermal
Unit BTU
British Thermal
Unit/pound BTU/lb
cubic feet/minute cfm
cubic feet/second cfs
cubic feet cu ft
cubic feet cu ft
cubic inches cu in
degree Fahrenheit F°
feet ft
gallon gal
gallon/minute gpm
horsepower hp
inches in
inches of mercury in Hg
pounds Ib
million gallons/day mgd
mile mi
pound/square
inch (gauge) psig
square feet sq ft
square inches sq in
tons (short) t
yard y
by TO OBTAIN (METRIC UNITS)
CONVERSION ABBREVIATION METRIC UNIT
hectares
cubic meters
kilogram - calories
kilogram calories/kilogram
cubic meters/minute
cubic meters/minute
cubic meters
liters
cubic centimeters
degree Centigrade
meters
liters
liters/second
killowatts
centimeters
atmospheres
kilograms
cubic meters/day
kilometer
atmospheres (absolute)
square meters
square centimeters
metric tons (1000 kilograms)
meters
0.405
1233.5
0.252
0.555
0.028
1.7
0.028
28.32
16.39
0.555(°F-32)*
0.3048
3.785
0.0631
0.7457
2.54
0.03342
0.454
3,785
1.609
ha
cu m
kg cal
kg cal/kg
cu m/min
cu m/min
cu m
1
cu cm
°C
m
1
I/sec
kw
cm
atm
kg
cu m/day
km
(0.06805 psig +1)* atm
0.0929 sq m
6.452 sq cm
0.907 kkg
0.9144 m
* Actual conversion, not a multiplier
AU.S. GOVERNMENT PRINTING OFFICE:1974 583-414/82 1-3
339
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UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON. D.C. 20460
OFFICIAL BUSINESS
PENALTY FOR PRIVATE USE $300
AN EQUAL OPPORTUNITY EMPLOYER
POSTAGE AND FEES PAID
U.S. ENVIRONMENTAL PROTECTION AGENCY
EPA-339
WH-452
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