EPA
Group I, Phase II
Development Document For
Effluent Limitations Guidelines
(BPCTCA)
for the
BLEACHED KRAFT, GROUNDWOOD,
SULFITE, SODA, DEINK AND
NON-INTEGRATED PAPER MILLS
Segment of the
PULP, PAPER, AND PAPERBOARD
Point Source Category
\
UNITED STATES ENVIRONMENTAL
PROTECTION AGENCY
DECEMBER 1976
-------
DEVELOPMENT DOCUMENT
for
EFFLUENT LIMITATIONS GUIDELINES
(BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY AVAILABLE)
for the
BLEACHED KRAFT, GROUNDWOOD, SULFITE, SODA,
DEINK, AND NON-INTEGRATED PAPER MILLS SEGMENT
of the
PULP, PAPER, AND PAPERBOARD MILLS
POINT SOURCE CATEGORY
Russell E. Train
Administrator
Andrew w. Breidenbach, Ph.D.
Assistant Administrator for
Water and Hazardous Materials
Eckardt C. Beck
Deputy Assistant Administrator
for Water Planning and Standards
Robert B. Schaffer
Director, Effluent Guidelines Division
Craig Vogt and Richard Kinch
Project Officers
December 1976
Effluent Guidelines Division
Office of Water and Hazardous Materials
U.S. Environmental Protection Agency
Washington, D.C. 20460
-------
ABSTRACT
This document presents the findings of an extensive study of
the following segment of the pulp and paper industry:
groundwood, sulfite, bleached kraft, soda, deink, and non-
integrated paper mills, for the purpose of developing
effluent limitations for existing sources in compliance with
Sections 301 and 304, of the Federal Water Pollution Control
Act Amendments of 1972 (the "Act").
The subcategories of pulp, paper, and paperboard point
source category established in this study are the following:
1. Bleached Kraft: Dissolving Pulp
2. Bleached Kraft: Market Pulp
3. Bleached Kraft: Fine Papers
H. Bleached Kraft: B.C.T. Papers
5. Papergrade Sulfite (Blow Pit Wash)
6. Papergrade Sulfite (Drum Wash)
7. Dissolving Sulfite Pulp
8. Soda
9. Groundwood: Chemi-mechanical (CMP)
10. Groundwood: Thermo-mechanical (TMP)
11. Groundwood: Fine Papers
12. Groundwood: C.M.N. Papers
13. Deink
1U. Non-Integrated Fine Papers
15. Non-Integrated Tissue Papers
16. Non-Integrated Tissue Papers (fwp)
This subcategorization does not include two types of
operations by non-integrated paper mills. These operations
are non-integrated paper mills producing coarse and
specialty papers. Effluent limitations will be developed
for these types of mills at a later date.
Effluent limitations are set forth for the degree of
effluent reduction attainable through the application of the
"Best Practicable Control Technology Currently Available,"
which must be achieved by existing point sources by July 1,
1977.
The identified technology for July 1, 1977, is good inplant
waste water management followed by preliminary screening,
primary sedimentation, and biological treatment. The 1977
limitations can be met by mills utilizing only biological
treatment, but a combination of inplant controls and
biological treatment may be more cost-effective.
111
-------
Supportive data and rationale for development of the
effluent limitations and standards of performance are
contained in this report.
IV
-------
TABLE OF CONTENTS
Section Title Page
I Conclusions 1
II Recommendations 3
III Introduction 11
Purpose and Authority 11
Summary of Methods used for Development of the
Effluent Limitations and Standards 11
Selection of Mills for on-site Survey
in 1973-74 12
Mill Survey Program 14
Data Handling and Computer Program 16
Inplant Control Survey Program 18
General Description of Industry Segments 19
Products 24
Daily Production Capacity 29
Mill Characterization: Daily Production 30
Size Distribution 33
Geographical Distribution of Mills 35
Annual Production 35
Pulp and Papermaking Processes 35
Wood Preparation 35
Mechanical Pulping 46
Stone Groundwood 47
Refiner Groundwood 47
Thermo-mechanical 50
Cold Soda 50
Chemi-groundwood 50
Bleaching of Mechanical Pulp 51
Bleaching with Peroxides 51
Bleaching with Hydrosulfites 53
Process Variables 53
Description of Process 55
Type of Hydrosulfite Used 57
Chemical Pulping of Wood 58
Sulfite 59
Bleached Kraft 63
Soda 66
Bleaching of Chemical Pulp 69
Oxygen bleaching 72
Displacement Bleaching 79
Bleaching of Dissolving Pulps 79
Deinked Pulp 81
Bleaching of Deinked Pulp 84
Papermaking 84
-------
Section Title
IV Subcategorization of the Industry 89
Factors of Consideration 89
Definition of Subcategories 90
Rationale for Selection of Subcategories 93
Raw Materials 94
Production Processes 109
Products Produced 112
Age and Size and Mills 113
Geographical Location 122
Subcategory Rationale 126
Bleached Kraft Subcategories 126
Sulfite Subcategories 136
Groundwood Subcategories 144
Soda Subcategory 147
Deink Subcategory 147
Non-integrated Paper Mills
Subcategories 148
V Water Use and Waste Characterization 153
Use of Water in Pulp and Paper
Manufacture 154
Wood Preparation 160
Log Transport and Defreezing Operations 160
Log Washing and Chip Washing/Dethawing
Operations 162
Barking Operations 163
Wet Barking Raw Waste Characteristics 169
Pulping Processes 172
Groundwood Subcategories 172
Development of Subcategory RWL 179
Sulfite Subcategories 188
Papergrade Sulfite Subcategories 188
Development of Subcategory RWL 192
Dissolving Sulfite Subcategories 203
Development of Subcategory RWL 206
Bleached Kraft Subcategories 214
Development of Subcategory RV7L 228
Bleached Kraft Dissolving Pulp
Subcategory 228
Bleached Kraft Market Pulp Subcategory 231
Bleached Kraft BCT Papers Subcategory 233
Bleached Kraft Fine Papers Subcategory233
Soda Subcategory 238
Development of Subcategory RWL 242
Deink Subcategory 244
Development of Subcategory RWL 245
Papermaking 250
Water Use and Reuse 250
Waste Water Characteristics 252
Development of Subcategory RWL 256
VI
-------
Section Title page
Non-integrated Fine Papers Subcategory 256
Non-Integrated Tissue Papers
Subcategory 261
Non-Integrated Tissue Papers (fwp)
Subcategory 261
VI Selection of Pollutant Parameters 265
Waste Water Parameters of Significance 265
Rationale for Parameters not Selected 277
VII Control and Treatment Technologies 281
Internal Technologies 282
General 282
Groundwood Subcategories 284
Sulfite Subcategories 285
Bleached Kraft Subcategories 286
Soda Subcategory 291
Bleaching of Chemical Pulps 291
Deink Subcategory 295
Papermaking 296
NI Fine Papers Subcategory 299
NI Tissue Papers Sutcategory 299
Identification of BPCTCA Internal Technology 399
External Technologies 329
Removal of Suspended Solids 329
Reduction of BODjj 334
Aerated Stabilization Basins (ASB) 335
Activated Sludge (A) 337
Ditch Aeration 338
Rotating Biological Surfaces 332
Trickling Filters 339
Two Stage Biological Treatment 339
Impact of Temperature Variations 34Q
BOD15 Kinetics 34!
Variations in Process Supply, Water
Temperature, and Consumption 342
Heat Transfer 343
Effects on Biological Treatment Systems 344
Sludge Handling and Disposal 34o
Irrigation and Land Disposal of Effluents .,54
Foam Control
Treatment Systems for Removal of Zinc
External Treatment and Effluent Characteristics
at Surveyed Mills
Bleached Kraft Mills
soda Mills
Groundwood Mills
Deink Mills
Sulfite Mills
NI Fine Papers Mills
vn
-------
Section Title
Page
NI Tissue Papers Mills 403
Variability of Effluent Discharges from
Surveyed Mills 406
Unit Processes Used in Cost Development 425
VIII Costs, Energy, Non-Water Quality Aspects 447
Development of Costs 447
Internal Technology Costs 45^
External Treatment Technology 453
Impact of Climate Variations 474
Energy Requirements 492
Waste Sludge Disposal 492
Costs of Sludge Disposal 495
Cost of SSL Recovery 5Q3
Retrofit Costs 5Qg
Alternative Technology 5*2
Incineration 512
Zinc Removal 525
Air Pollution Potential 534
Noise Potential 538
By-Product Recovery 538
By-Products of Kraft Pulping 539
By-Products of Sulfite Pulping 541
Implementation Requirements 544
Availability of Equipment 544
Availability of Construction Manpower 543
Construction Cost Index 548
Land Requirements 549
Time Required to Construct Treatment
Facilities 549
IX Best Practicable Control Technology Currently
Available 555
Introduction 555
Effluent Reduction Attainable Through BPCTCA 555
Allowances for Wet Woodyard Operations 555
Effluent Limitations for Non-Continuous
Dischargers 553
Identification of BPCTCA 553
Rationale for Selection of BPCTCA 554
Age and Size of Equipment and Facilities 554
Processes Employed 554
Non-water Quality Environmental Impact
Cost of Application in Relation to Effluent
Reduction Benefits
Rationale for Selection of Effluent Limitations
Bleached Kraft subcategories ___
Groundwood Subcategories
Sulfite Subcategories
Soda Subcategory
Vlll
-------
Section Title
Deink Subcategory 584
Non-Integrated Paper Mills Subcategories 585
Pretreatment Requirements 591
X Acknowledgements 593
XI References 595
XII Glossary 625
XIII Terminology Index 633
IX
-------
LIST OF TABLES
Number Title Page
1 BPCTCA Effluent Limitations in
kg/kkg (Ibs/ton) 4
2 Allowances for Wet Barking Operations
Effluent Limitations in kg/kkg (Ibs/ton) 5
3 Allowances for Log Washing or Chip
Washing Operations Effluent Limitations
in kg/kkg (Ibs/ton) 6
4 Allowances for the Use of Log Flumes
or Log Ponds Effluent Limitations
in kg/kkg (Ibs/ton) 7
5 Effluent Limitations for Non-Continuous
Dischargers 8,9,10
6 Summary of Surveyed Mills 15
7 Parameters Measured and Abbreviations 17
8 Bleaching Symbols 23
9 Products of Subject Industry Segment 25,26,27
10 Distribution of Mills 32
11 Tabular Description of Non-Integrated
Papermaking Mills 36
12 1972 Production by Pulp Type and
Paper Grades 45
13 Comparison of Bleaching Agents for
Aspen Groundwood 57
14 Common Sequences Used to Bleach Kraft
Pulp to Various Degrees of Brightness 78
15 Samples of Shrinkage of Various Types
of Paper on Deinking 83
16 Subcategory Raw Waste Loads - BPCTCA 95
17 Bleached Kraft Subcategories, Wood
Type vs Raw Waste Load 97
XI
-------
Number Title Page
18 Bleach Kraft Effluent Characteristics 100
19 Bleached Kraft Hardwood/Softwood vs
Product 104
20 Sulfite Subcategories - Age/Wood Type
vs Raw Waste Load 105
21 Bleached Kraft Subcategories, Age
vs Raw Waste Load 115
22 Raw Waste BOD vs Number of Machines 123
23 Bleached Kraft Brightness vs Bleaching 128
24 Brightness vs Bleach Stage, Kraft Pulping 129
25 Bleached Kraft Mills, Brightness and
Bleach Plant Sequences 132
26 Bleached Kraft Subcategories: Market
Pulp and Dissolving Pulp Mills, Brightness
Levels and Bleach Plant Sequences 135
27 Papergrade Sulfite Process Variables
vs Raw Waste Load 139
28 Brightness vs Bleach Stage, Sulfite
Pulping 141
29 Groundwood, Raw Waste Load vs Brightness 146
30 Comparison of 1965 vs 1972-3 Water Use 155
31 Mercury in Waste Waters 156
32 Zinc in Waste Waters 157
33 Log Washing Effluents 162
34 Log Washing Effluent Characteristics 163
35 Analysis of Wet Drum Barking Effluents 165
36 Raw Waste Characteristics - Wet
Drum Barking 167
37 Analysis of Hydraulic Barking Effluent 170
38 Hydraulic Barker Effluents 171
xii
-------
Number Title Page
39 Raw Waste Characteristics - Debarking
Operations 173
40 Summary of Woodyard Operations Raw
Waste Characteristics 174
41 Raw Waste Load - GW-Chemi-Mechanical
Subcategory 180
42 Raw Waste BOD5_ - GW: Thermo-Mechanical
Mills 183
43 BOD5_ vs Groundwood Yield 184
44 Raw Waste Load - GW-Fine Papers Subcategory 185
45 Raw Waste Load - GW-CMN Papers Subcategory 186
46 Zinc Raw Waste Loads - Groundwood Mills 189
47 Typical Effluent Loadings from Individual
Processes in a Sulfite Pulp Mill 190
48 Mill Characteristics and Raw Waste Loads,
Sulfite Mills 194
49 Sulfite Mills: Age, Location,
Climate, Treatment 195
50 Impact of Neutralization of SSL on
Condensate BOD_5 Levels 198
51 Papergrade Sulfite (Blow Pit Wash)
Subcategory Raw Waste Characteristics 199
52 Papergrade Sulfite (Drum Wash) Subcategory
Raw Waste Characteristics 200
53 Papergrade Sulfite Subcategories -
Barometric and Surface Condensers -
Raw Waste Characteristics 201
54 Papergrade Sulfite Subcategories - Summary
of Raw Waste Characteristics 204
55 Characteristics of Dissolving Sulfite
Pulps 20?
56 Dissolving Sulfite Pulps - Raw Waste
Characteristics 211
Kill
-------
Number Title Page
57 Dissolving Sulfite Pulps - Summary: Raw
Waste Characteristics 212
58 Volume and Characteristics of
Kraft Bleaching Wastes (5) 220
59 Kraft Bleaching Raw Waste Characteristics 221
60 Raw Waste Characteristics of Various
Stages of Bleaching 222
61 Constituents of Five Stage Bleaching
Effluent 223
62 Raw Waste Color Data from Surveyed Mills 225
63 Color Waste Loads - Bleached Kraft Mills 226
64 Raw Waste Load, BK: Dissolving Pulp
Subcategory 229
65 Raw Waste Characteristics - Bleached
Kraft: Dissolving Pulp Mills 230
66 Raw Waste Load, Bleached Kraft-Market
Pulp Subcategory 232
67 Raw Waste Load, BK-BCT & Market Mills 234
68 Raw Waste Load - BK-Fine & MKT Mills 235
69 Raw Waste Load, Bleached Kraft-Fine
Paper Subcategory 239
70 Raw Waste Load: Bleached Kraft Mills,
Multiple Subcategory Mills 240
71 Raw Waste Load, Soda Subcategory 243
72 Solids and BOD5_ Loading From Deinking
Mill Operations 246
73 Deink Mill Shrinkage 247
74 Raw Waste Load, Deink Mills 249
75 Raw Waste Load - Deink Subcategory 251
76 Estimated Water Usage for Papermaking 253
xiv
-------
Number Title page
77 Estimated Water Usage for Fourdrinier
Showers 254
78 Estimated Non-Equilibrium Papermaking
Losses 257,258,259
79 Raw Waste Load, NI Fine Subcategory 260
80 Raw Waste Load, NI Tissue Subcategory 262
81 Raw Waste Load, NI Tissue (FWP)
Subcategory 263
82 BPCTCA Internal Measures Used at Surveyed
Mills 301
83 Internal Control Technology Used for
BPCTCA Cost Analysis 302
84 Mill Size (Used for Cost Analysis) 303
85 Month of Maximum Average BOD at Final
Discharge for Surveyed Mills with ASB 347
86 External Technologies Currently in Use 359
87 Bleached Kraft Mills, Final Effluent
Characteristics 379
88 Bleached Kraft Mills, Biological Treatment:
Effluent Characteristics (mg/1) 381
89 Bleached Kraft Mills, Final Effluent
Characteristics: Mills with ASB's 386
90 Bleached Kraft Mill, Final Effluent
Characteristics: Mills with A's 387
91 Bleached Kraft Mills, Final Effluent
Characteristics: Mills with ASB's or
A1s without PS 388
92 Bleached Kraft Mills, Final Effluent
Characteristics: Mills with ASB's or
A1s with PS or C 389
93 Bleached Kraft Mills, Final Effluent
Characteristics vs Type of Treatment
Facilities 390
xv
-------
Number Title Page
94 Soda Subcategory: Final Effluent
Characteristics 392
95 Groundwood Mills: Final Effluent
Characteristics 393
96 Deink Mills: Final Effluent Characteristics
97 Sulfite Mills: Biological Treatment Data
98 Sulfite Mills: Biological Treatment:
Influent vs Effluent (BOD5J 3gg
99 Influent vs Effluent: BOD5_ - Best Mills
100 NI Fine Papers Subcategory: Final
Effluent Characteristics 404
101 NI Tissue Papers Mills: Final
Effluent Characteristics 405
102 Effluent Variability Ratios 409,410,411
103 Variability of Mills with Activated
Sludge Treatment Systems 417
104 Daily BOD5_ Variability: Raw Waste
vs Final Effluent 423
105 Variability Factors 425
106 Variability Factors for Non-Continuous
Dischargers 426
107 Hon-Continuous Dischargers - Final
Effluent Concentration Variability 427
108 Non-Continuous Dischargers - Final Effluent
Concentration Variability 428
109 Design Criteria for Cost Analysis 442,443
110 BPCTCA Waste Water Characteristics 448
111 Model Mill Sizes 450
112 Number of Paper Machines:
Model Mills 452
113-129 Effluent Treatment Costs: Aerated
Stabilization and Activated Sludge
(All Subcategories) 458-473
xvi
-------
Number Title page
130 Total Mill Energy Requirements:
Baseline and Additional 493,494
131 Economics of MgO Recovery 506,507
132 Surveyed Mills Used to Determine
Retrofit Costs 513,514
133 Basis for Retrofit Cost Determination
GW, S, SO, D, F Subcategories 515
134 Basis for Retrofit Cost Determination
BK Subcategories 516
135 Basis for Retrofit Cost Determination
T Subcategories 517
136 Retrofit Effluent Treatment Costs
GW, S, SO & DE Segments 518
137 Retrofit Effluent Treatment Costs
BK Segment 519
138 Retrofit Effluent Treatment Costs
NI Segment 520
139 Unsurveyed Mills Requiring Retrofit,
Bleached Kraft Segment 521
140 Retrofit Cost for Bleached Kraft Segment 522
141 Retrofit Cost for Tissue Segment 523
142 Zinc Removal Technology - Capital and
Operating Costs 536
143 Mills Manufacturing Spent Sulfite
Liquor By-Products 542
144 BPCTCA Effluent Limitations 557
145 Effluent Limitations for Non-Continuous
Dischargers 559-561
146 Variability Factors for Non-Continuous
Dischargers 562
147 Cost of BPCTCA vs Effluent Reduction
Benefits 566
xvn
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Number Title
Page
148 BPCTCA Variability Factors 569
149 Basis for BPCTCA Effluent Limitations 570
150 Bleached Kraft Subcategories, Best
Mills: Final Effluent Characteristics 572,573
151 Groundwood Subcategories: Best Mills 578
152 Deink Subcategory: Basis for Effluent
Limitations 586
153 NI Tissue Mills: Basis for Effluent
Limitations 590
154 Conversion Table 638
XVlll
-------
LIST OF FIGURES
Number Title Page
1 Distribution of U.S. Groundwood Mills 3-7
2 Distribution of U.S. Sulfite Mills 38
3 Distribution of U.S. Bleached Kraft and
Soda Mills 39
4 Distribution of U.S. Deinked Mills 40
5 Distribution of U.S. Non-Integrated Fine
Paper Mills 41
6 Distribution of U.S. Non-Integrated Tissue
Mills 42
7 Stone Groundwood Pulp Mill Process Flow
Diagram 48
8 Refiner Groundwood Pulp Mill Process
Flow Diagram 49
9 Brightening and Bleaching Groundwood and
Cold Soda Pulps Process Flow Diagram 52
10 Sulfite Pulp Mill Process Flow Diagram 51
11 Magnesium Base Sulfite Recovery System
Process Flow Diagram 62
12 Bleached Kraft Pulping Process Flow Diagram 55
13 Kraft Chemical Recovery Process QJ
14 Kraft Recovery System Process Flow Diagram 53
15 Chemical Reaction Involved in the Soda Pulp
Mill Recovery System 70
16 Four Stage Kraft Pulp Bleach Plant Process
Flow Diagram 73
17 Three Stage Sulfite Pulp Bleach Plant
Process Flow Diagram 74
18 Oxygen Bleach Plant at Surveyed Mill 124 75
xix
-------
Number Title Page
19 Oxygen Bleach Plant at Swedish Mill 76
20 Planned Displacement Bleach Plant at
Surveyed Mill 121 80
21 Deinking Plant Process Flow Diagram 85
22 Three Stage Deinked Pulp Bleach Plant
Process Flow Diagram 86
23 Paper Manufacturing Process Flow Diagram 88
24 Raw Waste Flow vs Type of Wood 98
25 Raw Waste BOD_5 vs Type of Wood 99
26 Raw Waste Flow vs Type of Wood -
Bleached Kraft 102
27 Raw Waste BOD.5 vs Type of Wood -
Bleached Kraft 103
28 Bleached Kraft Segment, Production
vs BODS 118
29 Bleached Kraft Segment, Production
vs Flow 119
30 Non-Integrated Fine, Production vs
Flow 120
31 Non-Integrated Fine, Production vs
BODS 121
32 BOD vs Number of Machines Bleached Kraft
Segment 124
33 Bleach Kraft Segment, Brightness
vs Flow 130
34 Bleach Kraft Segment, Brightness vs
BODS 131
35 NI Fine % C+F vs BODS 149
36 NI Fine % C+F vs Flow 150
37 Wet Barking Process Diagram 164
38 Effluent Characteristics: Groundwood Mill 176
xx
-------
Number Title Page
39 Effluent Characteristics: Sulfite Mill 193
40 Effluent Characteristics: Sulfite
Dissolving Mill 208
41 Effluent Characteristics: Bleached
Kraft Mill 215
42 Effluent Characteristics: Soda Mill 241
43 Effluent Characteristics: Deink Mill 248
44-65 Internal Control Schematics 305-333
66 Effect of Temperature on Biological
Treatment System 248
67 Surveyed Mill External Treatment:
Schematics 360-378
68 Bleached Kraft Mills, Biological Treatment:
Effluent Characteristics 382
69 Bleached Kraft Mills, Biological Treatment:
Influent vs Effluent (BODS) 383
70 Sulfite Mills, Biological Treatment:
Influent vs Effluent (BODS) 400
71 Influent vs Effluent: BOD5_ -
Best Mills 402
72 Daily Effluent BOD Data for Mill 117 407
73 Daily Maximum BODS Variability 413
74 Daily Maximum TSS Variability 414
75 30 day Maximum BOD'S Variability 415
76 30 day Maximum TSS Variability 416
77 Daily Maximum BODS Variability for
NI Tissue Mills 419
78 Daily Maximum TSS Variability for
NI Tissue Mills 420
79 30 day Maximum BODS Variability for
NI Tissue Mills 421
xxi
-------
Number Title Page
80 30 day Maximum TSS Variability for
NI Tissue Mills 422
81 Non-Continuous Dischargers - Final Effluent
Concentration Variability - BOD5_: Max. Day 429
82 Non-Continuous Dischargers - Final Effluent
Concentration Variability -
BOD5_: Max. 30 Days 430
83 Non-Continuous Dischargers - Final Effluent
Concentration Variability - TSS: Max. Day 431
84 Non-Continuous Dischargers - Final Effluent
Concentration Variability -
TSS: Max. 30 Days 432
85-87 Schematics: Model Mill External
Treatment Technology 444-446
88 Effluent Treatment Facility:
Northern Climate 473
89 Landfill Capital Costs: 40% Sludge 499
90 Landfill Operating Costs: 40% Sludge 500
91 Landfill Transportation Costs: 40% Sludge 501
92 Sludge Incineration: Capital Costs 526
93 Sludge Incineration: 0 & M Costs -
40% Sludge 527
94 Sludge Incineration: 0 & M Costs -
30% Sludge 528
95 Sludge Incineration: 0 & M Costs -
20% Sludge 529
96 Sludge Incineration - Energy
Requirements 530
97 Sludge Incineration - Fuel Requirements -
40% Sludge 531
98 Sludge Incineration - Fuel Requirements -
30% Sludge 532
99 Sludge Incineration - Fuel Requirements -
20% Sludge 533
xxn
-------
Number Title Page
100 Zinc Removal Treatment Facility Costs 535
101 Total Water Pollution Control Expenditures 545
102 Waste Water Treatment Equipment Sales 545
103 Engineering News Record Construction
Cost Index 559
104 Minimum Area Required for Wastewater
Treatment 551
105 Time Requirement to Construct Wastewater
Facilities Conventional and Turnkey Contracts 553
XXlll
-------
-------
SECTION I
CONCLUSIONS
For the purpose of establishing effluent limitations, the
bleached kraft, groundwood, sulfite, soda, deink and
nonintegrated paper mills segment of the pulp, paper, and
paperboard point source category has been subcategorized as
follows:
Groundwood: Chemi-mechanical
Groundwood: Thermo-mechanical
Groundwood: CMN Papers
Groundwood: Fine Papers
Bleached Kraft: Dissolving Pulp
Bleached Kraft: Market Pulp
Bleached Kraft: BCT Papers
Bleached Kraft: Fine Papers
Soda
Papergrade Sulfite (Blow Pit Wash)
Papergrade Sulfite (Drum Wash)
Dissolving Sulfite Pulp
Deink
Non-Integrated Fine Papers
Non-Integrated Tissue Papers
Non-Integrated Tissue Papers (FWP)
Factors such as age, size of plant, raw material, process
employed, product, climate, and waste treatability confirm
and substantiate this subcategorization for the purpose of
establishing effluent limitations to be achieved through the
application of identified treatment and control
technologies.
The 1977 requirement of best practicable technology
currently available (BPCTCA) suggests biological waste
treatment as the basic treatment process for all except the
non-integrated tissue papers subcategory. Primary treatment
is suggested for the latter. Limitations are set forth for
BODji, total suspended solids, pH, and zinc.
-------
-------
SECTION II
RECOMMENDATIONS
INTRODUCTION
The effluent limitations for existing sources are shown in
Tables 1, 2, 3, 4 and 5 for BPCTCA.
The average of daily values for 30 consecutive days should
not exceed the maximum 30 day average shown in the tables.
The value for any one day should not exceed the daily
maximum as shown in the tables. For non-continuous
dischargers, annual average limitations are presented in
kg/kkg (Ibs/ton); maximum 30 day averages and daily maximums
are presented in mg/1. 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 5.0 to 9.0.
Production shall be defined as the annual off-the-machine
production (including off-the-machine coating where
applicable) divided by the number of operating days during
that year. Paper production shall be measured in the off-
the-machine moisture content whereas market pulp shall be
measured in air-dry-tons (10% moisture). Production shall
be determined for each mill based upon past production
practices, present trends, or committed growth.
-------
TABLE 1
BPCTCA
EFFLUENT LIMITATIONS IN KG/KKG(lbs/ton)
Subcategory
Maximum 30 Day Average
Maximum Day
BODS
Dissolving Kraft
Market Kraft
BCT Kraft
Fine Kraft
Papergrade Sulfite (Blow
Bisulfite-Surface
Bi sulf i te-Barometr ic
Acid Sulfite Surface
12.
8.
7.
5.
25
05
1
5
(24.5)
(16.1)
(14.2)
(11.0)
20
16
12
11
TSS
.05
.4
.9
.9
(40
(32
(25
(23
.1)
.8)
.8)
.8)
BODS
23.6
15.45
13.65
10.6
(47.2)
(30.9)
(27.3)
(21.2)
TSS
37.3
30.4
24.0
22.15
(74.6)
(60.8)
(48.0)
(44.3)
Pit Wash)
16.
18.
16.
Acid Sulfite-Barometric 18.
Papergrade Sulfite (Drum
Bisulfite-Surface
Bisulfite-Barometric
Acid Sulfite-Surface
Wash)
13.
15.
15.
Acid Sulfite-Barometric 16.
Continuous Digesters
Dissolving Sulfite
Nitration
Viscose
Cellophane
Acetate
GW-Chemi-Mechanical
GW-Thermo-Mechanical
GW-CMN Papers
GW-Fine Papers
Soda
Deink
NI Fine Papers
NT Tissue Papers
NI Tissue Papers (FWP)
ph for all subcategories
Subcategory
GW-Chemi-Mechanical
GW-Thermo-Mechanical
GW-CMN Papers
GW-Fine Papers
19.
21.
23.
25.
26.
7.
5.
3.
3.
7.
9.
4.
6.
7.
shall
55
05
8
5
9
3
5
9
85
55
05
0
45
05
55
9
6
1
4
25
25
1
(33.1)
(36.1)
(33.6)
(37.0)
(27.8)
(30.6)
(31.0)
(33.8)
(39.7)
(43.1)
(46.1)
(50.0)
(52.9)
(14.1)
(11.1)
( 7.8)
( 7.2)
(14.2)
(18.8)
( 8.5)
(12.5)
(14.2)
23
28
23
28
23
28
23
28
28
38
38
38
38
10
8
6
6
13
12
5
5
9
.65
.1
.65
.1
.65
.1
.65
.1
.95
.05
.05
.05
.05
.65
.35
.85
.3
.2
.95
.9
.0
.2
be within the range
Maximum
0.17
0.13
0.15
Zinc*
(47
(56
(47
(56
(47
(56
(47
(56
(57
(76
(76
(76
(76
(21
(16
(13
(12
(26
(25
(11
(10
(18
of
.3)
.2)
.3)
.2)
.3)
.2)
.3)
.2)
.9)
.1)
.1)
.1)
.1)
.3)
.7)
.7)
.6)
.4)
.9)
.8)
.0)
.4)
5.0
30-day Average
(0.
(0.
(0.
0.135 (0.
34)
26)
305
27)
31.8
34.7
32.3
35.55
26.7
29.4
29.75
32.5
38.15
41.4
44.3
48.05
50.8
13.5
10.6
7.45
6.85
13.7
18.1
8.2
11.4
13.7
to 9.0
(63.6)
(69.4)
(64.6)
(71.1)
(53.4)
(58.8)
(59.5)
(65.0)
(76.3)
(82.8)
(88.6)
(96.1)
(101.6)
(27.0)
(21.2)
(14.9)
(13.7)
(27.4)
(36.2)
(16.4)
(22.8)
(27.4)
43.95
52.2
43.95
52.2
43.95
52.2
43.95
52.2
53.75
70.65
70.65
70.65
70.65
19.75
15.55
12.75
11.75
24.5
24.05
11.0
10.25
17.05
(87.9)
(104.4)
(87.9)
(104.4)
(87.9)
(104.4)
(87.9)
(104.4)
(107.5)
(141.3)
(141.3)
(141.3)
(141.3)
(39.5)
(31.1)
(25.5)
(23.5)
(49.0)
(48.1)
(22.0)
(20.5)
(34.1)
Maximum Day
0.34
0.26
0.30
0.275
(0.68)
(0.52)
(0.60)
(0.55)
*Applicable only to mills using zinc hydrosulfite
-------
TABLE 2
BPCTCA
ALLOWANCES FOR WET BARKING OPERATIONS
EFFLUENT LIMITATIONS IN kg/kkg (Ibs/ton)
Subcategory
Dissolving Kraft
Market Kraft
BCT Kraft
Fine Kraft
Papergrade Sulfite
Blow Pit Wash
Papergrade Sulfite
Drum Wash
Dissolving Sulfite
GW-Chemi-Mechanical
GW-Thermo-Mechanical
GW-CMN Papers
GW-Fine Papers
Soda
Maximum 30 Day Average
BOD5
1.7
1.2
1.2
1.0
1.45
1.6
0.35
0.45
0.45
0.55
0.55
1.1
(3.4)
(2.4)
(2.4)
(2.0)
(2.9)
(3.2)
(0.7)
(0.9)
(0.9)
(1.1)
(1.1)
(2.2)
TSS
3.75
2.85
3.1
2.85
3.95
3.95
0.1
1.45
1.45
1.1
1.1
2.8
(7.5)
(5.7)
(6.2)
(5.7)
(7.9)
(7.9)
(0.2)
(2.9)
(2.9)
(2.2)
(2.2)
(5.6)
Maximum Day
BODs TSS
3.2 (6.4) 6.9 (13.8)
2.3 (4.6) 5.3 (10.6)
2.25 (4.5) 5.75 (11.5)
1.95 (3.9) 5.3 (10.6)
2.7 (5.4) 7.5 (15.0)
3.05 (6.1) 7.5 (15.0)
0.7 (1.4) 0.15 (0.3)
0.9 (1.8) 2.6 (5.2)
0.9 (1.8) 2.7 (5.4)
1.15 (2.3) 2.0 (4.0)
1.1 (2.2) 1.95 (3.9)
2.05 (4.1) 5.25 (10.5)
-------
TABLE 3
BPCTCA
ALLOWANCES FOR LOG WASHING OR CHIP WASHING OPERATIONS
EFFLUENT LIMITATIONS IN KG/KKG (IBS/TON)
Maximum 30 Day Average Maximum Day
Subcategory BODS TSS BODS TSS
Dissolving Kraft 0.2 (0.4) 0.4 (0.8) 0.35 (0.7) 0.7 (1.4)
Market Kraft 0.1 (0.2) 0.3 (0.6) 0.2 (0.4) 0.6 (1.2)
BCT Kraft 0.15 (0.3) 0.35 (0.7) 0.25 (0.5) 0.65 (1.3)
Fine Kraft 0.1 (0.2) 0.3 (0.6) 0.2 (0.4) 0.55 (1.1)
Papergrade Sulfite
Blow Pit Wash 0.1 (0.2) 1.35 (2.7) 0.15 (0.3) 2.55 (5.1)
Papergrade Sulfite
Drum Wash 0.2 (0.4) 1.35 (2.7) 0.35 (0.7) 2.55 (5.1)
Dissolving Sulfite 0.1 (0.2) 0.1 (0.2) 0.15 (0.3) 0.15 (0.3)
GW-Chemi-Mechanical 0.05 (0.1) 0.15 (0.3) 0.05 (0.1) 0.25 (0.5)
GW-Thento-Mechanical 0.05 (0.1) 0.15 (0.3) 0.05 (0.1) 0.3 (0.6)
GW-CMN Papers 0.05 (0.1) 0.15 (0.3) 0.15 (0.3) 0.2 (0.4)
GW-Fine Papers 0.05 (0.1) 0.15 (0.3) 0.15 (0.3) 0.2 (0.4)
Soda 0.1 (0.2) 0.25 (0.5) 0.15 (0.3) 0.5 (1.0)
-------
TABLE 4
BPCTCA
ALLOWANCES FOR THE USE OF LOG FLUMES OR LOG PONDS
EFFLUENT LIMITATIONS IN KG/KKG (IBS/TON)
Maximum 30 Day Average Maximum Day
Subcategory BODS TSS BODS TSS
Dissolving Kraft 0.35 (0.7) 0.8 (1.6) 0.6 (1.2) 1.45 (2.9)
Market Kraft 0.2 (0.4) 0.6 (1.2) 0.4 (0.8) 1.15 (2.3)
BCT Kraft 0.25 (0.5) 0.7 (1.4) 0.45 (0.9) 1.25 (2.5)
Fine Kraft 0.2 (0.4) 0.6 (1.2) 0.35 (0.7) 1.15 (2.3)
Papergrade Sulfite
Blow Pit Wash 0.2 (0.4) 0.9 (1.8) 0.35 (0.7) 1.7 (3.4)
Papergrade Sulfite
Drum Wash 0.35 (0.7) 0.9 (1.8) 0.7 (1.4) 1.7 (3.4)
Dissolving Sulfite 0.1 (0.2) 0.1 (0.2) 0.15 (0.3) 0.15 (0.3)
GW-Chemi-Mechanical 0.05 (0.1) 0.3 (0.6) 0.15 (0.3) 0.55 (1.1)
GW-Thento-Mechanical 0.1 (0.2) 0.35 (0.7) 0.15 (0.3) 0.6 (1.2)
GW-CMN Papers 0.1 (0.2) 0.25 (0.5) 0.25 (0.5) 0.45 (0.9)
GW-Fine Papers 0.05 (0.1) 0.25 (0.5) 0.2 (0.4) 0.4 (0.8)
Soda 0.2 (0.4) 0.55 (1.1) 0.3 (0.6) 1.1 (2.2)
-------
TABLE 5
BPCTCA
EFFLUENT LIMITATIONS FOR NGN-CONTINUOUS DISCHARGES
Subcategory
Dissolving Kraft
Market Kraft
BCT Kraft
Fine Kraft
Papergrade Sulfite (Blow Pit Wash)
Bisulfite-Surfaoe
Bisulfite-Baronetric
Acid Sulfite-Surfaoe
Acid Sulfite-Barometric
Papergrade Sulfite (Drun Wash)
Bisulfite-Surface
Bisulfite-Barcmetric
Acid Sulfite-Surface
Acid Sulfite-Baronetric
Continuous Digesters
Dissolving Sulfite
Nitration
Viscose
Cellophane
Acetate
GW-Chemi-Mechanical
GW-ThernD-Mechanical
GW-CMN Papers
GW-Fine Papers
Soda
Deink
NI Fine Papers
NI Tissue Papers
NI Tissue Papers (FWP)
Annual Average
kg/kkg (Ibs/ton)
Maximum 30 Day Average
BODS
6.9 (13.8)
4.5 ( 9.0)
4.0 ( 8.0)
3.1 ( 6.2)
9.3 (18.6)
10,15 (20.3)
•9.45 (18.9)
10.4 (20.8)
7.8 (15.6)
8.6 (17.2)
8.7 (17.4)
9.5 (19.0)
11.15 (22.3)
12.1 (24.2)
12.95 (25.9)
14.05 (28.1)
14.85 (29.7)
3.95 ( 7.9)
3.1 ( 6.2)
2.2 ( 4.4)
2.0 ( 4.0)
4.0 ( 8.0)
5.3 (10.6)
2.4 ( 4.8)
3.5 ( 7.0)
4.0 ( 8.0)
TSS
11.05 (22.1)
9.0 (18.0)
7.1 (14.2)
6.55 (13.1)
13.0 (26.0)
15.45 (30.9)
13.0 (26.0)
15.45 (30.9)
13.0 (26.0)
15.45 (30.9)
13.0 (26.0)
15.45 (30.9)
15.9 (31.8)
20.9 (41.8)
20.9 (41.8)
20.9 (41.8)
20.9 (41.8)
5.85 (11.7)
4.6 ( 9.2)
3.75 ( 7.5)
3.45 ( 6.9)
7.25 (14.5)
7.1 (14.2)
3.25 ( 6.5)
2.85 ( 5.7)
5.05 (10.1)
BODS
56
48
50
45
93
86
95
87
78
73
87
80
91
82
87
95
100
165
65
41
41
52
97
71
69
71
TSS
86
94
86
92
126
126
126
126
126
126
126
126
126
137
137
137
137
94
94
68
68
92
126
92
54
86
Maximum Day
mg/1
BCD5
98
84
88
78
162
150
166
153
136
127
153
140
159
143
153
166
176
114
114
72
72
91
169
124
120
124
TSS
168
182
168
178
245
245
245
245
245
245
245
245
245
266
266
266
266
182
182
133
133
178
245
178
105
168
-------
TABLE 5 (Gont.)
ALLOWANCES (ANNUAL AVERAGE)
Subcategory
Dissolving Kraft
Market Kraft
BCT Kraft
Fine Kraft
Papergrade Sulfite (Blow Pit Wash)
Bisulfite-Surfaoe
Bisulfite-Baronetric
Acid Sulfite-Surfaoe
Acid Sulfite-Baronetric
Papergrade Sulfite (Drum Wash)
Bisulfite-Surfaoe
Bisulf ite-Barometric
Acid Sulfite-Surfaoe
Acid Sulfite-Barometric
Continuous Digesters
Dissolving Sulfite
Nitration
Viscose
Cellophane
Acetate
GW-Chemi-Mechanical
GW-ThentD-Mechanical
GW-CMI Papers
GW-Fine Papers
Soda
Wet Barking
kg/kkg (Ibs/ton)
BODS
0.95
0.7
0.65
0.55
0.8
OJ
0Ts
0.8
0.9
0.9
0.9
0.9
0.9
0.2
0.2
0.2
0.2
0.25
0.3
0.3
0.35
0.6
(1.9)
(1.4)
(1.3)
(1.1)
(1.6)
(1.6)
(1.6)
(1.6)
(1.8)
(1.8)
(1.8)
(1.8)
(1.8)
(0.4)
(0.4)
(0.4)
(0.4)
(0.5)
(0.6)
(0.6)
(0.7)
(1.2)
TSS
2.0
1.55
1.7
1.55
2.2
2.2
2.2
2.2
2.2
2.2
2.2
2.2
2.2
0.05
0.05
0.05
0.05
0.8
0.75
0.6
0.6
1.55
(4.0)
(3.1)
(3.4)
(3.1)
(4.4)
(4.4)
(4.4)
(4.4)
(4.4)
(4.4)
(4.4)
(4.4)
(4.4)
(0.1)
(0.1)
(0.1)
(0.1)
(1.6)
(1.5)
(1.2)
(1.2)
(3.1)
Log or Chip Washing
kg/kkg (Lbs/ton)
BODS
0.1
0.1
0.05
0.05
0.05
0.05
0.05
0.05
0.1
0.1
0.1
0.1
0.1
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
(0.2)
(0.2)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.2)
(0.2)
(0.2)
(0.2)
(0.2)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
TSS
0.2
0.15
0.2
0.15
0.75
0.75
0.75
0.75
0.75
0.75
0.75
0.75
0.75
0.05
0.05
0.05
0.05
0.1
0.05
0.1
0.1
0.15
(0.4)
(0.3)
(0.4)
(0.3)
(1.5)
(1.5)
(1.5)
(1.5)
(1.5)
(1.5)
(1.5)
(1.5)
(1.5)
(0.1)
(0.1)
(0.1)
(0.1)
(0.2)
(0.1)
(0.2)
(0.2)
(0.3)
Log Flumes or Ponds
kg/kkg (Ibs/ton)
BCD5
0.2
0.15
0.1
0.1
0.1
0.1
0.1
0.1
0.2
0.2
0.2
0.2
0.2
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.1
(0.4)
(0.3)
(0.2)
(0.2)
(0.2)
(0.2)
(0.2)
(0.2)
(0.4)
(0.4)
(0.4)
(0.4)
(0.4)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.2)
TSS
0.4
0.35
0.35
0.3
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.05
0.05
0.05
0.05
0.15
0.15
0.15
0.15
0.35
(0.8)
(0.7)
(0.7)
(0.6)
(1.0)
(1.0)
(1.0)
(1.0)
(1.0)
(1.0)
(1.0)
(1.0)
(1.0)
(0.1)
(0.1)
(0.1)
(0.1)
(0.3)
(0.3)
(0.3)
(0.3)
(0.7)
-------
TABIE 5 (Cont.)
ZINC
Annual Average
Subcategory kgAkg (Ibs/ton)
GW-Chemi-Mechanical 0.115 (0.23)
GS^Therno-Mechanical 0.085 (0.17)
GW-CMJ Papers 0.10 (0.20)
GW-Fine Papers 0.09 (0.18)
10
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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 lr 1977, of effluent limitations for point
sources, other than publicly owned treatment works, which
are based on the application of the best practicable control
technology currently available (BPCTCA) as defined by the
Administrator pursuant to Section 30<»(b) of the Act.
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
procedure innovations, operation methods, and other
alternatives. The information herein sets forth effluent
limitations guidelines pursuant to Section 30U(b) of the Act
for the groundwood, sulfite, bleached kraft, soda, deink and
the non-integrated paper mills segment of the pulp, paper,
and paperboard point source category.
SUMMARY OF METHODS USED FOR DEVELOPMENT OF THE EFFLUENT
LIMITATIONS AND STANDARDS OF PERFORMANCE
A literature search and screening program were undertaken in
order to identify all the mills in the segment. Directories
which describe the production processes and products
manufactured by each mill in the pulp and paper industry
were used, along with industry journals, direct mill
contact, and contractor knowledge.
Next, information describing the waste water treatment
facilities and the quantity and quality of the waste water
discharged by each mill was tabulated. In this effort,
assistance was provided by EPA regional offices which
provided NPDES data and other pertinent information.
Various state pollution control agencies also cooperated in
furnishing waste water discharge and additional data. The
National Council for Air and Stream Improvement also
provided considerable assistance. It was particularly
11
-------
valuable in verifying data obtained from other sources which
appeared to need clarification and/or substantiation. In
addition, an in-depth literature search was conducted to
strengthen the data base and to provide information on the
internal and external control technologies used by the
various mills.
This program culminated in the tabulation of approximately
358 mills that qualify for inclusion in this study. In this
total, each mill site is counted only once, even though it
may encompass multiple physical facilities housing more than
one pulping and/or papermaking process. While there is
considerable variation in reporting numbers of "mills11
within the industry, this approach was used because of its
relationship to the total raw waste load of an industrial
complex.
Selection of Mills for On-Site Survey Conducted in 1973-74
Screening sheets were prepared showing, by mill, information
and data pertaining to production, raw waste loads, final
effluent qualities, and external treatment facilities.
Evaluation of this information indicated that it was an
adequate basis upon which to select those mills that would
provide the broad-based in-depth information necessary to
subcategorize the segment and to identify BPCTCA. It should
be noted that information was subsequently updated and
corrected as the study progressed.
These mills were candidates for on-site surveys which were
to be made to assure the reliability and validity of the
performance ascribed to them. The purpose of the on-site
mill inspections was evaluation of the production processes
and waste treatment facilities and to verify the quality of
the production and waste water data generated by the mill.
The selection of a mill as a survey candidate was made on a
descending order of priorities. First priority was an
operating treatment facility that included biological
treatment of the entire process waste water. Second
priority was the quality of the final discharge after
treatment and the quantity of waste per unit of production
generated by the mill. Predicated on these criteria, 74
mills appeared to be candidates for mill survey; of these,
44 were bleached kraft, nine, in groundwood, one, soda, and
four each in the remaining three. Except for bleached kraft
all of the mills with biological treatment were selected.
Twenty-five of the 44 mills in bleached kraft utilizing
12
-------
secondary treatment were selected, and the remaining 19
mills were eliminated for one or more of the following
reasons:
1. The available data indicated poor performance of
treatment facilities.
2. The mill used two or more pulping processes
involving substantial unbleached kraft and/or semi-chemical
pulp production. The waste generated by such complex mills
would therefore not be representative of any single segment
included in this study.
3. Abnormally high raw waste values suggested minimal
utilization of internal controls.
4. Waste water discharge data were not available.
5. Non-standard analytical procedures and/or flow
measuring devices were used.
The 25 bleached kraft mills selected adequately represent
bleached kraft manufacturing in terms of raw materials, pro-
duction processes, geographic locations, internal and
external control practices, and age and size of mill. This
was not the case, however, with the mills with biological
treatment in the other parts of the segments. Therefore, it
was necessary to select mills for survey, other than
bleached kraft, on the basis of well-operated primary
treatment facilities and/or available raw waste data to
broaden the data base for subcategorization and to define
waste water characteristics for each subcategory. In
addition, considerations of raw material usage, processes,
number of production units, geographic location, internal
and external control practices, and age and size of mill
were balanced among additional selections. As a result, the
total number of mills selected for on-site survey reached
10U, or over 25 percent of all the mills in this segment.
Records on waste treatment facilities, waste water
discharge, and productifor processes were also obtained on
10 additional mills.
I
Following these original data collection efforts, the
resulting data base was evaluated to determine how
representative the available data was of each subcategory.
From this analysis, additional efforts were made to collect
data from an additional 70 mills and further data from
approximately 30 mills previously surveyed. Collection of
the additional information and data involved on-site
surveys, written correspondence, and telephone surveys. The
13
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data collected from mills previously surveyed has been
combined with the data from the original survey efforts in
most cases but in several cases the added data are
identified in this report with the original mill code
followed by an "A" (i.e. 101A). The number of mills
surveyed and the percent that this represents of the total
number of mills in each segment is shown in Table 6.
The mill survey program resulted in a very extensive data
base with detailed information and data on approximately 200
mills. The waste water data collected during the sampling
efforts represented at least 12 months of daily discharge
and production values. For 30 to 40 mills of these mills,
the collected data represented two to three years of mill
operations.
Mill Survey Program
A comprehensive mill survey format was developed for
completion at the mill site by a survey team. The format
was designed to make it possible to equate the information
obtained at one mill with that of all mills included in the
survey and to evaluate the many variables associated with
production processes and waste treatment.
The analytical test procedures used by each mill were
documented and the deviations from standard methods employed
for several waste water parameters were noted. The type of
flow measuring and sampling devices used were also recorded
and evaluated as to their reliability. Information
regarding the production capacity and raw materials used by
the mill was obtained, and the dates on which production
facilities and/or waste treatment facilities were installed,
modified, or updated were established.
The survey form was also designed to quantify to the extent
possible the internal and external technologies employed at
each mill and the extent to which these technologies were
used. It was accompanied by single-line block diagrams of
the production process and waste streams generated by each
process. Similar diagrams of the waste treatment facilities
were sketched showing the sampling and flow measurement
points for which the mill had 12 months of records. Such
records of data on all routinely tested streams and
parameters were requested.
14
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TABLE 6
SUMMARY OF SURVEYED MILLS
Segment
Total No.
of Mills
Groundwood
Sulfite
Bleached Kraft
Soda
Deink
Fine
Tissue
39
30
74
3
17
46
74
283
Mills with Percent No. of Percent
Secondary of Mills of
Treatment (1973) Segment Surveyed Segment
8 21 22 56
6 20 24 80
42 56 40 52
1 33 3 100
6 35 15 88
4 9 21 46
4 5 25 34
70 150 53
15
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Data Handling and Computer Program
The production and waste treatment records obtained were
subjected to detailed screening and evaluation to 1)
eliminate obviously erroneous data and 2) code each waste
stream for which mills did have usable records in order to
develop a uniform and consistent data format for computer
programming. The evaluation and coding program culminated
in the completion of Survey Form Number 7. This form
provided the computer programmer with the mill code number,
the kkg/day (tons/day) of production attributable to each
mill, the waste streams described by the data, and the
parameters to be used for computer input. Parameters tested
by one or more mills are identified in Table 7. Together
with the abbreviations used in computer outputs. It should
be noted particularly that non-standard test methods are
identified in the computer analysis by the letter "N"
following the abbreviation. Such data must be used very
cautiously since it is not comparable to data obtained by
standard methods. The definition of standard methods for
all parameters except color was derived from Standard
Methods for the Examination of Water &_ Waste Water, 13th
edition (191). In the case of color, the method outlined in
National Council for Air and Stream Improvement Bulletin 253
(192) was used to define the standard method. For total
suspended solids, either the fiberglass method described in
current editions of Standard Methods or the asbestos method
described in earlier editions was taken as the standard
metnod.
The computer program provided the following data output for
each of the "computerized" mills:
1. Annual means for individual waste streams for all
parameters for which there were data.
2. Monthly averages for all available parameters on the
total raw waste and the final discharge.
3. The 30-maximum-day values for all waste parameters
available for the final discharge.
4. Three types of statistical plots for all available
final effluent parameters for 45 surveyed mills. To the
extent possible the mills selected for these plots used
biological treatment facilities; for those segments in which
few mills have biological treatment mills with well operated
primary treatment facilities were included. The three plots
can be described as follows: (a) frequency distribution
16
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Table 7
PARAMETERS MEASURED AND ABBREVIATIONS
Parameter
5-Day Biochemical
Oxygen Demand
Temperature
Total Suspended Solids
Color
Turbidity
Zinc
Phosphate
pH
Nitrogen
Ammonia Nitrogen
Settleable Solids
Chemical Oxygen Demand
Total Solids
Total Volatile solids
Abbrevi ations*
BODj> or BOD
Temp
TSS
Color
Turbid
ZINC
POU
PH
N or Nitrogen
NH4 or Ammonia
Setslds
COD
TS
TVS
*The letter "N" following the abbreviation was used to
designate a non-standard method of laboratory analysis.
17
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histogram; (b) a cumulative probability plot; (c)
chronological plot.
From the cumulative probability plot the minimum data value,
maximum data value, mean value, standard deviation,
coefficient of variation, and number of data days are
determined for each parameter plotted. The chronological
plot is actually three plots of a given parameter. One plot
is of the daily data value; the next is the average of four
calendar days; and the third plot is the 30-calendar-day
moving average. In all cases, missing data are excluded
from the averaging calculation and the averages are
determined from the actual data available within the
calendar time specified — i.e., four days or 30 days.
Extensive analyses of the data were conducted to determine
effluent variability and these analyses are described in
Section VII.
Inplant Control Survey Program
Subsequent to the completion of the survey program described
above, a new survey program was initiated to collect
extensive data on the use and potential use of inplant
controls for raw waste load reduction within the segment of
the industry included in this report. Although the program
was not complete at the time of publication of this
Development Document, items related to BPCTCA have been
completed and are presented in Section VII.
18
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GENERAL DESCRIPTION OF INDUSTRY SEGMENTS
Paper is made from raw materials which contain adequate
amounts of cellulose fiber, its basic component. The
cellulose must first be separated from other constituents of
the fiber source and fiberized. This is the function of the
pulping process. During the 19th century, wood began to
supplant cotton and linen rags, straw, and other less
plentiful fiber sources. Today, wood accounts for over 98
percent of the virgin fiber used in papermaking.
This report deals exclusively with wood pulp and products
made primarily from it and the reclamation of waste papers.
There are several methods used for pulping wood. In some,
it is cooked with chemicals under controlled conditions of
temperature, pressure, time, and liquor composition (1).
These processes use different chemicals or combinations of
them. In other methods, wood is reduced to a fibrous state
by mechanical means alone or by a combination of chemical
and mechanical action.
Mechanical pulp is commonly called groundwood. In the basic
process, stone groundwood pulp is made by tearing fiber from
the sides of short lengths of logs called billets with a
grindstone; pulp produced by passing wood chips through a
disc refiner is termed refiner groundwood. In the chemi-
groundwood (chemi-mechanical) process, the billets are first
pressure impregnated with a dilute solution of sodium
sulfite before grinding; in cold soda pulping, chips are
steeped in a caustic solution and refined. Such
pretreatment softens the wood so that less power is required
for grinding. In a new process, thermo-mechanical pulping,
chips are first softened with heat and then refined under
pressure. These general descriptions are subject to
modification in practice.
Although groundwood pulp was initially shunned by the makers
of fine paper when the basic process was introduced in this
country in the last century, today it is considered a very
versatile pulp and is put to many uses. Its initial success
in the manufacture of paper was its acceptance for newsprint
and that is still its primary market. The major
disadvantage of groundwood, impermanence, is offset by the
economy of its production, especially for the manufacture of
the wide range of "throw-away" products demanded by 20th
century Americans -tissues, toweling, paper plates, etc. —
and the millions of "paperbacks" printed every year. The
mechanical pulps of more recent vintage — refiner, cold
19
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soda, chemi-groundwood, and thermo-mechanical — are also
components of diversified products.
Both of the major chemical pulping processes used in the
United States today, sulfite and kraft (or sulfate) , had
their origins in the 19th century. Kraft was commercially
developed in the early 1900's and it was the soda process,
the alkaline forebear of kraft, which was the competitor of
sulfite pulping for some grades of pulp during the 19th
century. With the ascendancy of the kraft process, most
soda mills converted to kraft in order to produce a stronger
pulp, and subsequent developments have minimized the
differences between the two (2). Currently, there are only
two major mills which report the production of soda pulp
from wood fiber. These mills are engaged in the manufacture
of fine papers.
Sulfite pulps are associated with both tissue and fine
papers and in combination with other pulps, they have many
papermaking capabilities. In addition, dissolving pulps,
the highly purified chemical cellulose used in the
manufacture of rayon, cellophane, and explosives, were
produced solely by the sulfite process for many years.
Sulfite pulping developed using calcium as the sulfite
liquor (2) because of an ample and cheap supply of limestone
(calcium carbonate). The use of calcium as a sulfite base
has declined in recent years because 1) the difficulty and
expense of recovering or burning spent liquor from this base
was not economic to the operation and the absence of non-
polluting disposal methods precluded their compliance with
water quality standards and/or effluent limitations; and 2)
the diminishing availabilities of soft woods which are most
suitable for calcium-base pulping (3)(4). In addition, 3)
attempts to use more than about 10 percent of the spent
liquor in various by-products failed. As a result, most
acid sulfite mills have changed to a soluble base
magnesium, ammonia, or sodium — which permits recovery or
incineration of the spent liquor. Several mills have
switched to the kraft pulping process (4)(5). During the
1973-4 survey period, only nine mills used a calcium base;
nine employed magnesium, 10 used ammonia, and four used
sodium. Only four sulfite mills have been built since the
1940's — two of them in Alaska. Three of these mills
produce chemical cellulose or specialty pulps, and the
fourth manufactures tissue grades.
Kraft is currently the dominant pulping method and over 80
percent of the chemical pulp produced in this country is
made by this process. Three major developments were
20
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primarily responsible for this achievement. First, chemical
recovery, because of the cost of chemicals used, is an
economic necessity to this process, and, in the 1930«s,
successful recovery techniques were applied and since have
been vastly improved. Second, the process was found to be
adaptable to nearly all wood species and its application to
southern pines resulted in a rapid expansion of kraft
pulping (2). Third, new developments in kraft bleaching
techniques spurred another dramatic growth period just after
World War II.
Sulfite, the naturally brightest unbleached pulp and the
most easily bleached one, had been preeminent in the light-
color grades (3). Kraft, bleached by new processes which
retained its superior strength, began to replace sulfite in
many bleached papers. Kraft made further inroads on
traditional sulfite markets with the production of
dissolving pulps and kraft pulps for greaseproof and tissue
papers (3). Today, a broad spectrum of printing and fine
papers, tissue, food and milk containers, and boxes and
containers of many other varieties are manufactured from
bleached kraft pulp.
However, acid sulfite pulps do possess distinct properties
which are superior for some products. These include special
grades of dissolving pulps, tissues, and some grades of fine
paper.
Although wood supplies the fiber for the great majority of
pulp produced in this country, about 21 percent of the paper
and paperboard produced annually is reused as a raw material
for new products. Large quantities of this, are used in
coarse products such as waste paperboard, building papers,
etc.f without extensive pretreatment. (The manufacture of
these products is covered in earlier EPA Development
Documents) .
Some reclaimed papers, however, are deinked before reuse.
Deinked pulp provides an important fiber source which is
competitive in cost, conserves wood resources, and, in some
cases, improves product quality when incorporated in the
furnish (6). Deinking of waste paper was in commercial
operation during the last century although the large scale
operations existing today developed much more recently. In
addition to removing ink, fillers, coatings, and other non-
cellulosic materials must also be removed in order to
reclaim useful pulp. These materials are added to modern
papers to impart special characteristics (such as superior
printing qualities, gloss, wet strength, grease resistance,
etc.) (6). Deinked pulp is used in business, bank, and
21
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printing papers, tissues and toweling, as liner for some
paperboards, and in molded products and newsprint.
Unbleached pulp is brown in color primarily because of the
lignin content of the wood. It is bleached to modify or
remove the color bodies in order to produce a light colored
or white product. Bleaching techniques are also used in the
manufacture of dissolving pulps.
The degree of bleaching pulp for paper manufacture is
measured in terms of units of brightness and is determined
optically by established TAPPI methods (7). Partially
bleached pulps (semi-bleached) are employed in newsprint,
food containers, computer cards, and similar papers. Fully
bleached pulp is used for white paper products. By
different degrees of bleaching, pulp of the desired
brightness can be manufactured up to a level of 96 on the
brightness scale of 100. These techniques are described in
detail in a TAPPI monograph (8).
Bleaching is frequently performed in several stages in which
different chemicals are applied. The symbols commonly used
to describe a bleaching sequence are shown and defined in
Table 8. The table can be used to interpret bleaching
"shorthand," which is used extensively in later sections of
this report. For example, a common sequence in kraft
bleaching, CEDED, is interpreted as follows:
Chlorination & Washing
Alkaline Extraction & Washing
Chlorine Dioxide 6 Washing
Alkaline Extraction & Washing
Chlorine Dioxide & Washing
Almost all sulfite pulps are bleached, but usually a shorter
sequence such as CEH is sufficient to obtain bright pulps.
This sequence involves chlorination, alkaline extraction,
and hypochlorite application, each followed by washing.
Some mills manufacture paper and/or paperboard which do not
make pulp. These are called non-integrated paper mills and
the pulp they use is either shipped from another of the
company's facilities or is purchased. Pulp mills which do
not have attendant papermaking operations are a major source
of pulp for these mills, and some integrated mills also sell
"market" pulp.
The papermaking process is generally the same regardless of
the type pulp used or the end product produced. A layer of
fiber is deposited, from a dilute water suspension of pulp,
22
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Taole 8
BLEACHING SYMBOLS
A - Acid Treatment or Dechlorination
C - Chlorination
D - Chlorine Dioxide
E - Alkaline Extraction
H - Hypochlorite
HS - Hydrosulfite
O - Oxygen
P - Peroxide
PA - Peracetic Acid
W - Water Soak
( ) - Simultaneous Addition of the Respective Agents
/ - Successive Addition of the Respective Aqents without
Washing in Between
23
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on a fine screen, called the "wire", which permits the water
to drain through and retains the fiber layer (2) . This
layer is then remo'ved from the wire, pressed, and dried.
Two basic types of paper machines and variations thereof are
commonly employed. One is the cylinder machine in which the
wire is on cylinders which rotate in the dilute furnish, and
the other is the fourdrinier in which the dilute furnish is
deposited upon an endless wire belt. Generally, the
fourdrinier is associated with the manufacture of paper and
the cylinder with paperboard.
Products
Table 8 illustrates the diversity of papers manufactured by
integrated pulp and paper mills and non-integrated paper
mills. The various grades are delineated according to end
use and/or furnish.
Although this list represents the production of the mills
subject to this report by grade, a complete tally of their
products as listed in industry directories would include
numerous other terminologies. Since this multiplicity of
nomenclature essentially defines specialized uses of
products which themselves fall within the generic grade
classifications of Table 9, they are not separately itemized
here.
The major fundamental differences in the various papers are
durability, basis weight, thickness, flexibility,
brightness, strength, and color. These characteristics are
a function of raw material selection, pulping methods,
and/or papermaking techniques.
As has already been noted, some pulps are naturally more
adaptable for certain paper grades than for others. This is
influenced by fiber length, strength, and other factors
which can be controlled by the woods employed, the selection
of a pulping process, cooking chemicals, length of cook,
etc. With improved techniques and the ability to mix pulps
to achieve desired properties, however, few paper grades are
uniquely a product of one pulp only.
In addition to variations in stock preparation and sheet
control on the paper machine, the papermaking operation may
enhance the basic qualities of paper, or achieve other
properties — such as wet strength, greaseproofness,
printing excellence, etc. -- through the use of additives.
These include a variety of substances such as starch, clay,
and resins used as fillers and coatings.
24
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Table 9
PRODUCTS OF INDUSTRY SEGMENT (1)
PAPER
I. Newsprint
II. Printing-Writing Papers
A. Uncoated Groundwood
1. Publishing & Printing
2. Converting
B. Coated Papers
C. Uncoated Book
1. M.S.,E.F., Etc. (2) & Super Calendered
2. Offset
3. Envelope
4. Tablet
D. Papers Made from Chemical Wood Pulp
1. Bond & Writing
2. Form Bond
3. Ledger
U. Mimeograph
5. Duplicator
6. Manifold
7. Papeterie & Wadding
8. Body Stock for Commercial & Copying
9. Other Technical & Reproduction Paper
10. Opaque Circular
11. Colored School
E. Cover & Text Papers
(1) Excerpted from Paper and Paperboard Statistics 1973,
American Paper Institute, and API's Paper, Paperboard, Wood
Pulp Capacity 1971-1974.
(2) Machine Finish, English Finish.
25
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Table 9 - Cont'd.
F. Thin Papers
1. Carbonizing
2. Condenser
3. Ciqarette
G. Bleached Eristols
1. Tabulating Index
2. Tag
3. File Folder
4. Index Bristol
5. Postcard
6. Coated Bristol
III. Unbleached Kraft 8 Bleached Packaging Papers
A. Unbleached Kraft Papers
1. Wrapping
2. Bag & Sack
3. Shipping Sack
4. Other Converting
B. Bleached Packaging Papers
1. Wrapping
2. Bag 6 Sack
3. Shipping Sack
4. Other Convering
IV. Glassine, Greaseproof, 5 Vegetable Parchment
V. Special Industrial Papers
VI. Tissue Papers
A. Sanitary Tissue
1. Toilet
2. Facial
3. Napkins
4. Sanitary Napkins
5. Towels
6. Wipers
B. Non-Sanitary Tissue
1. Wa xi ng
2. Wrapping
3. Industrial Cellulose
4. Miscellaneous
26
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Table 9 - Contd.
PAPEREGARD
Bleached(3)
Milk Cartons
Folding Cartons
Heavyweight Cup, Rounded Nested Food Containers, & Cup Lids
Plate, Dish, 6 Tray
Other Packaging
Linerboard
Non-Packaging
Unbleached(4)
Linerboard
Boxboard (Folding Carton)
Chip and Filler Boards
(3)Paperboard made from 85S or more bleached chemical wood pulp.
(4)Solid unbleached wood pulp paperboard.
27
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The grades listed in Table 9 are, for the most part, self-
explanatory, and definitions according to industry usage may
be found in the publication Paperq Paperboard, Wood Pulp
Capacity 1971-197U of the American Paper Institute (API)
(9). However, for purposes of this study, the many separate
grades have been grouped under four major headings:
newsprint, fine papers, tissue, and coarse papers.
Newsprint is, of course, separately identified in Table 9.
Tissue, too, is clearly set apart except that, in the
context of this report, glassine, greaseproof, and vegetable
parchment are included in the tissue segment. These papers
are basically a tissue sheet treated with additives to serve
specific purposes. For example, glassine is a lightly waxed
tissue familiar as candy wrappers and envelope windows.
Fine papers include all printing and writing papers. Coarse
papers include: kraft packaging papers (used for grocery
and shopping bags, heavy wrapping paper, and sacks for
shipping sugar, flour, cement, and other commodities);
paperboard (the materials of boxes, cartons, and other
containers); and the less expensive industrial papers.
While unbleached kraft linerboard (the smooth facing on
"corrugated boxes") produced by integrated unbleached kraft
pulp and paper mills was the subject of an earlier study,
some mills covered by this investigation also produce
linerboard and other unbleached kraft paperboards. This is
also true of several non-integrated mills and a few
integrated mills which make other pulps in addition to
unbleached kraft, although their tonnage of the latter is
very small in comparison with the output of the large
unbleached kraft mills.
Special industrial papers include paper and boards of all
weights, calipers, and furnishes designed for specialized
end uses, such as abrasive and absorbent papers, cable
papers, electrical insulation, vulcanized fiber , resin-
impregnating stock, and similar grades (9). Thus, in
grouping them in toto as "coarse" papers, some
inconsistencies occur within the usual meaning of that term.
It is felt, however, that their production is more closely
related to coarse paper manufacture than to the other
segments,
Paperboard is, of course, a type of paper and the terms
"paper" and "paperboard" generally imply physical
differences only, some of which overlap in gradation.
Further, many mills produce, or have the capability to
produce, both products interchangeably. Therefore, they
28
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will not be treated separately in this report except when
necessary for clarification, and the phrase "paper/board" or
"paper" will be applied for simplification.
Many finished products made from the grades enumerated in
Table 8 do not arrive at the retail market directly from the
paper mill. While some mills have attendant operations
which convert their own stock into boxes, bags, envelopes,
paper plates, wall paper, food and milk containers, etc.,
much of the raw stock is sold to manufacturers of these
items. Whether or not the converting operations are
conducted on-site at the paper mill, they constitute a
separate and dry operation.
Daily Production Capacity
The daily production capacity of mills is an important con-
sideration in this report for two reasons. First, it is a
useful means of classifying mills, as discussed below.
Second, its correlation with waste water data makes it
possible to express pollutants discharged in pounds per ton
of product, the value used in effluent limitations
guidelines and standards.
Traditionally, limits on waste discharges were based on an
allowable concentration for each pollutant parameter. This
type of value, mg/1 (or ppm), is also used in this report to
characterize certain waste streams. However, the kilogram
per 1000 kilograms (pounds-per-ton) of product concept
equalizes the limitations among all mills, regardless of
size. In this report it is often expressed in the
abbreviated metric (English) unit expression "kg/kkg
(Ib/ton)." All waste parameter values reported in kg/kkg
(lb/ton) are based on an annual average of daily production.
"Ton" means a 907.20-kilogram or a short ton (2000-pound).
It should be pointed out that any averaging techniques used
in this report use the English units as the controlling
units and are presented with the corresponding metric
values. This point is especially important when any
"rounding-off" calculations and averaging techniques are
involved.
Except as otherwise noted, production includes the total
weight of product off the paper machine(s) plus pulp
dryer(s) where applicable, as reported by mills. Paper
machine production is in air-dry-tons (ADT). Pulp intended
for use offsite is expressed as "air dry" weight including
10 percent moisture. Where off-machine coaters were used,
the coat weight was included in the production weight
wherever sufficient data were available. In the case of on-
29
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machine coaters, the coat weight is automatically included
in the reported paper machine production weight. Where the
data furnished by mills did not meet these criteria, they
were converted to provide a uniform data base.
Mill Characterization According
to DailyProduction
Numbered among the mills discussed in this report are many
so-called complex mills — i.e., mills which produce more
than one variety of pulp or multiple paper grades.
The basis used for classifying complex pulp and integrated
mills was the pulping process which accounts for the largest
daily production capacity. For example, a mill with a daily
capacity to produce 340 kkg (375 tons) of groundwood pulp,
122 kkg {135 tons) of sulfite, 453 kkg (500 tons) of
newsprint, and 41 kkg (45 tons) of sulfite specialties was
classified as groundwood.
Strict application of this criterion, however, would result
in placing some of these mills in the segment covered in
EPA|S Development Document for the Unbleached Kraft and
Semi-Chemica1 Pulp Segment of the Pulp, Paper, and
Pa per board Mills Point Source Category (305|:. This is
particularly true where the production of unbleached kraft
is involved. The earlier study of this subcategory was
limited to those mills which produce no pulp other than
unbleached kraft. Thus, mills which have attendant kraft
bleaching or another pulping capacity fall within the scope
of this report although their largest production tonnage may
be unbleached kraft pulp. This is also the case with two
mills which produce more substantial quantities of semi-
chemical pulp, another subcategory covered by the above
Development Document, but which by virtue of their other
production were subject to this investigation. In these
instances, the mills have been grouped with those most
representative of their other pulping operations.
It is recognized, too, that application of the product
tonnage criterion to some non-integrated paper mills is
perhaps somewhat imprecise due to the fact that many of
these mills report the production of many grades
encompassing more than one product without accompanying
tonnage breakdowns. However, it is felt that the general
accuracy of the classification is sufficient to support the
statistical estimates of this section of the report.
30
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There are 38 groundwood mills; of these, 28 produce
groundwood pulp only. Nine additional groundwood operations
appear as bleached kraft and two as sulfite, making a total
of 49 U.S. groundwood mills. (Those mills producing a
different type of groundwood pulp used in building products
are not included) .
Twenty-nine mills produce sulfite pulp, 21 of which produce
sulfite pulp only. Four mills produce sulfite in addition
to groundwood, and four produce bleached kraft and NSSC.
Seventy-four mills are defined as bleached kraft, and five
are listed in conjunction with groundwood operations for a
total of 79. Thirty-eight produce bleached kraft only.
There are two soda ash pulp mills and an additional very
small soda operation with attendant sulfite and semi-
chemical pulping.
There are 17 deinking mills, 14 of which reclaim fiber for
the manufacture of fine papers and tissue and three which
produce newsprint. In addition, there is one
groundwood/deinking mill and one sulfite/deinking
combination.
A breakdown of these mills is shown in Table 10.
There are 46 non-Integrated fine paper mills and 74 non-
integrated tissue mills.
31
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Table 10
DISTRIBUTION OF MILLS
Type
Groundwood
Sulfite
Soda
Deink
No. of Mills
28 Groundwood
2 Groundwood/Bleached Kraft
1 Groundwood/Unbleached Kraft
3 Groundwood/Bleached/Unbleached Kraft
3 Groundwood/Sulfite
1 Groundwood/Deinked
38 Total
22
U
_a
30
Bleached Kraft 38
16
3
6
1
2
_
74
Sulfite
Sulfite/Groundwood
Sulfite/Bleached Kraft/NSSC
Total
Bleached Kraft
Bleached/Unbleached Kraft
Bleached Kraft/Groundwood
Bleached/Unbleached Kraft/Groundwood
Bleached/Unbleached Kraft/Sulfite
Bleached Kraft/Semi-Chemical
Bleached/Unbleached Kraft/Semi-Chemical
Bleached Kraft/Sulfite/Semi-Chemical
Total
2 Soda
17 Deink
32
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Size Distribution
The relative size of mills which produce only the one
designated type of pulp is illustrated as follows:
Groundwood
Sulfite
Bleached Kraft
Soda
Deinked
(Fine Paper
& Tissue)
(Newsprint)
Capacity
kkq (tons) /day
Largest
Mill
834 (920)
580 (640)
1379 (1520)
635 (700)
Median
Mill
181 (200)
209 (230)
454 (500)
222 (245)
Smallest
Mill
18 (20)
91 (100)
27 (30)
127 (140)
499 (550) 87 (96) 37 (41)
408 (450)* 272 (300)* 222 (245)*
*Paper production; pulp tonnage not published,
33
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Complex mills in groundwood, sulfite, and bleached kraft are
considered in size ranges as follows:
Capacity
kkg (tons) /day
Largest Median Smallest
Mill Mill Mill
Groundwood 1020 (1125) 172 (190) 18 (20)
Sulfite 771 (850) 209 (230) 25 (28)
Bleached Kraft 1379 (1520) 499 (550) 27 (30)
The total daily capacity of the mills listed in Table 10 has
been tabulated by pulp type. These figures, presented
below, represent the best estimates which can be made
utilizing published information and information gathered
during the course of the project. It must be emphasized,
however, that they are approximate only. This is especially
the case of the bleached kraft total because the
differential between bleached and unbleached production is
not always clearly identified.
Total Capacity
Pulp kkg (tons)/day
Groundwood 11,654 (12,850)
Sulfite 8,344 (9,200)
Bleached Kraft 72,379 (79,800)
Soda 907 (1,000)
Deinked 2,721 (3,000)
A separate breakdown is not presented for bleached and
unbleached groundwood and sulfite. There is relatively very
little sulfite pulp which is not bleached before use, and
groundwood undergoes many varying degrees of brightening or
bleaching, a tabulation of which would be imprecise.
Six sulfite mills and three bleached kraft mills produce
dissolving grades of pulp. The total capacity of these
sulfite mills is 2721 kkg (3000 tons) per day, and the kraft
34
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capacity is 2857 kkg (3150) tons per day; these figures,
however, include some bleached papermaking pulps. These
mills are included in the sulfite and kraft segment
tabulations.
The approximate total daily paper/board capacity for all
mills listed in the groundwood segment is 16,417 kkg (18,100
tons)/day; for the sulfite segment, 5442 kkg (6000
tons)/day; bleached kraft, 61,676 (68,000); soda, 1270
(1400); and deinked, 4535 (5000).
Size distribution of the non-integrated papermaking mills
appears in Table 11.
Geographic Distribution of Mills
The geographic distribution of the groundwood, sulfite,
bleached kraft and soda, deinked, non-integrated fine, and
non-integrated tissue mills are shown in Figures 1 through
6, respectively. The numbers refer only to the mills
designated according to the criteria discussed earlier.
Annual Production
Total annual production for 1972 of the products associated
with the subject industry is tabulated in Table 12 for
purposes of comparison.
PULP AND PAPERMAKING PROCESSES
Wood Preparation
Wood arrives at pulp mills in various forms and consequently
must be handled in a number of different ways. Some mills
receive their wood supply as logs, although the trend is
toward the use of purchased chips, or, in some cases,
sawdust and other residues of sawmill operation. For
example, in 1972 reclaimed chips and wood residues accounted
for 84 percent of the total wood volume consumed in pulp and
paper production in the Pacific Northwest (16).
The use of whole tree chipping (WTC) in the Northeast, Lake
States and South has increased considerably over the past
few years. This practice is particularly useful in mixed
stands of timber and for thin diameter material. It does
not require limbing and topping which are the most expensive
parts of wood handling. The use of cutter knives and blades
to cut up tree boles, branches and bark greatly increases
the yield of material per acre and 10-100% increases have
been found. A side benefit is that fewer roads are
35
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TABLE 13
TABULAR DESCRIPTION OF NON-INTEGRATED PAPERMAKING MILLS
00
Type of Mill
Fine Papers
Tissue
Coarse Papers
No. of
Mills
56
72
72
Total Capacity
kkg (tons) /day*
6651
(7333)
5465
(6025)
6295**
(6940)**
largest Mill
kkg (tons) /day
472
(520)
726
(520)
653
(720)
Smallest Mill
kkg (tons) /day
10.8
(12)
6.3
(7)
2.7
(3)
Median Mill
kkg (tons) /day
81.6
(90)
42.6
(47)
54
(60)
* Approximate.
** This figure is low due to nunfoer of mills not reporting tonnage.
-------
FIGURE 1
CO
""•4
DISTRIBUTION OF U.S. GROUNOWOOD MILLS O Groundwood
•»*.,
IMINNESCIA — ^.--.
'
,
r-^tx-j—T.JL
: l« .OKL
ARKANSAS i—*tENN
C.L^AUTYPE
STATE OUTLINE
UNITED STATES
-------
FIGURE 2
OJ
CO
DISTRIBUTION OF U.S. SULFITE MILLS
\ TMz&\ Q
VrasrV \ \
J«.—..«_ OKLAHOMA H^ _„_..—.—^ ^"""wPSSEE '**
/ 7£tflS ! -ARKANSAS ^ TtNN!^ X ^ *,^m
PP1I rvtoST "
* * ft ".Jf^-J! _
C.LJEAJJTYPE
STATE OUTLINE
UNITED STATES
-------
FIGURE 3
CJ
in
DISTRIBUTION OF U.S. BLEACHED KRAFT Bleached Kraft
AND SODA MILLS [—I .„.,
I I aoda
CLEARTYPE
STATE OUTLINE
UNITED STATES
-------
FIGURE 4
DISTRIBUTION OF U.S. DEINKED MILLS
CLEAR TYPI-
ST ATE Ol'TLINE |
UNITED STATfS
-------
FIGURE 5
DISTRIBUTION OF U.S. NON-INTEGRATED
FINE PAPER MILLS
O /
/••••'•W*-u -T--L j
• »•• — .. •JK,A"C'.-A |
CLLAUTyPK i
STATK (U'TI.INE I
uxrrrn STATES
-------
FIGURE 6
^ DISTRIBUTION OF U.S. NON-INTEGRATED TISSUE MILLS (^Tissue
^^~\
• NORTH DAXOTA""^" '••—%
j ll.VNNrSCIA
i \
.' I
CLEARTYPE
STATE OUTLINE
UNITED STATES
-------
necessary which are required for heavy-duty trucks. Thus,
there are lower costs per cubic foot of fiber produced.
However, the use of WTC in pulping process is still in the
developmental stage because of the increased required
maintenance of mill equipment, the added mill processing
equipment needed to process the WTC, impacts upon product
qualities, and increased waste water loadings.
Some of the most difficult problems are the inclusion of
sand, dirt, and abrasive materials as well as too much bark
in the WTC chips. This causes problems not only with the
cutting blades but also with mill equipment. The upkeep of
the mill equipment involves an increased cost of $10-$20 for
each dollar of field equipment used for debarking. This
equipment upkeep is necessitated by the unbarked chips
included with other material for pulping. The major pulps
produced from barky chips are semichemical pulp and
unbleached kraft. Several companies are now using 5% and up
to 30% WTC chips while unbleached kraft mills can use 2-5%
WTC chips. Several companies are using pulps with 5-15%
bark.
One company currently has in use over 275 WTC chipping
units. It is estimated that up to three times increase in
productivity per man hour can be obtained using field
chipping. One company estimated that in five years 80% of
their chips will be field chipped WTC wood.
Barked logs received at a mill are chipped directly for use
or cut into billets of suitable lengths for the stone and
chemi-groundwood processes. Bark is removed from unbarked
logs on the premises.
Most of the pulpwood used in the United States is small in
diameter and is barked dry in drums. When large diameter or
long wood is used, wet barking may be employed although this
practice is declining. The most common mechanisms for wet
barking are drum and hydraulic barkers (2)(3U) since the wet
pocket barker is now largely outmoded. Slabs are generally
handled by hydraulic units as is the large and longer round-
wood.
The wet drum barker consists of a slotted drum equipped with
internal staves which knock the bark from the wood as the
drum rotates in a pool of water. The bark falls through the
slots and is removed with the overflow of water.
Wet pocket barkers are stationary machines which abrade bark
from logs by jostling and slowly rotating confined wood
billets against each other. The bark passes out between the
43
-------
continuous chains which confine the logs. Water is sprayed
through apertures in the side of the pocket to soften the
bark and aid in its removal.
Hydraulic barkers employ high-pressure water jets to blow
the bark from the logs which is either conveyed past them or
rotated under a moving jet which traverses the log.
44
-------
Table 12
1972 PRODUCTION BY PULP TYPE AND PAPER GRADES
1000 kkg 1000 Tons
Pulp(l)
Special alpha &
dissolving 1,521 1,677
Sulfite 1,931 2,129
Bleached kraft 12,672 13,971
Soda 127 140
Groundwood 4,188 4,617
Paper(2)
Newsprint 2,360 2,602
Tissue 3,106 3,425
Fine papers 9,087(3) 10,019(3)
Coarse papers 10,310 11,367
(l)U.S.Bureau of the Census data.
(2)Contractor grouping of American Paper Insti-
tute data.
(3)Includes papers of textile fibers not subject
to this report.
45
-------
Wood Consumption
Typical wood consumption of median size mills is as follows:
Groundwood 120 cords/day
Sulfite 2U5 cords/day
Bleached Kraft 850 cords/day
Soda ' 125 cords/day
(It should be noted that conversions between cords and
tons should not be attempted without data on specific
situations. The reason for this is that a cord is a
measure of volume (U ft x U ft x 8 ft), while a ton is,
of course, a measure of weight. Variations in wood
species, density, diameter, straightness of log, etc.,
make conversions between the two units impossible for
general situations.)
Mechanical Pulping
The energy used in producing conventional groundwood pulp —
stone or refiner — is mechanical. Modified groundwood
processes such as the cold soda (chemi-mechanical) and
chemi-groundwood methods employ a mild chemical treatment
ahead of mechanical fiberizing. The latter processes are
considered here as mechanical pulping, however, because the
chemical pretreatment is much milder and the mechanical
action more drastic than is the case in semi-chemical
pulping. In thermo-mechanical pulping, an off-shoot of
refiner groundwood, the pretreatment is accomplished with
heat and pressure. The cold soda and chemi-groundwood pulps
are produced and used as a direct substitute for groundwood
(10) or as supplements to special furnishes. All mechanical
pulps contain practically all of the wood substance and
yields are generally 85 to 90 percent of the bone dry weight
of the wood processed while semi-chemical pulps fall within
the 60 to 80 percent yield range (2).
The type of wood economically available is a factor in
selection of the groundwood process applied. Softwood does
not necessarily require pretreatment (10) and has thus been
the traditional raw material of the stone groundwood
process, and more recently of the refiner method. The high
energy requirements of grinding untreated hardwood are
overcome by the processes which incorporate pretreatment.
Thus, their development made possible the use of large
stands of hardwood for mechanical pulping. Sawmill wastes
are another source of raw material for the mechanical
processes which use wood chips.
46
-------
Stone Groundwood
In this process, billets are fed to the grinders by hand or
automatically from a belt or chain conveyor (2) and are
forced hydraulically against the large rotating grindstone,
specifically designed for the purpose. The pocket-type
grinder is most common although the magazine, ring, and
continuous or chain types are being installed in new mills
(10). The grinding occurs in the presence of a large
quantity of water which acts as both a coolant and a carrier
to sluice the pulp from the body of the grinder. The pulp
slurry is diluted to a consistency of from 0.6 to 0.8
percent and is passed through coarse and fine screens and a
centri-cleaner to remove dirt and slivers. Over-size
rejects may be passed through a disc refiner and returned to
the system ahead of the fine screens. The pulp slurry is
then thickened on a decker to between 10 and 15 percent
consistency and discharged to a stock chest for mill use,
bleached, or thickened further for transport to other mills
(2) either in the form of wet lap at about 25 percent
consistency or nodules containing 50 percent fiber. A
diagram of the stone groundwood process is presented in
Figure 7.
Refiner Groundwood
The availability of saw mill waste as a low-cost wood source
led to the development and exploitation of the refiner
groundwood process which has the additional advantage of
using less power then stone grinding (11)(12). The chips
are first washed and two stages of refining are generally
employed in the pulp mill, the fiber receiving a third
refining in the paper mill. Disc type refiners are used
which contain one fixed and one rotary disc between which
the wood passes together with a stream of water. A double-
disc type unit is used mainly for refining rejects. The
pulp is discharged from the refiners at a consistency of
about eight percent and moved by a high-density pump to the
secondary units. Here it is diluted to low consistency and
subsequently fine screened and freed of dirt in centri-
cleaners. Screen rejects are refined and returned to
process ahead of the screens. After cleaning the pulp is
handled in the same manner as stone groundwood as shown in
the process flow diagram in Figure 8.
47
-------
FIGURE 7
STONE GROUNDWOOD PULP MILL
PROCESS FLOW DIAGRAM
PROCESS
WATER
i
REJECTS
REFINER
t
ALTERNATE
1
PULP DRYER
DEBARKED
ROUNDWOOD
J
1
GRINDERS
1
COARSE
SCREENS
J
1
FINE
SCREENS
J
CENTRICLEANERS
L
WHITE OVERFLOW
^ . u/flTFB - -— . . .h»
CHEST
1
FIBER
r i
DECKER
1
STOCK
CHEST
J
BLEACH OR
BRIGHTENING
FACILITIES
—1
*
PAPERMAKING
i
_^
.L
r~
L
1
"\
SEWER
.EGEND:
— — MAIN PROCESS
oLOONUAKY rRUCtSo
PROCESS WASTE LINE
48
-------
FIGURE 8
REFINER GROUNDWOOD PULP MILL PROCESS FLOW DIAGRAM
WOOD CHIPS
DEBARKED
ROUNDWOOD
CHIPPER
CHIP
STORAGE
REJECTS
REFINER
CHIP
WASHER
PRIMARY
REFINER
FEED
CONVEYOR
SECONDARY
REFINER
FINE
SCREENS
CENTR (CLEANERS
a DECKER
T
WHITE WATER
TANK
PROCESS WATER
MAKEUP
FIBER
WHITE
WATER*
SAVEALL
STOCK
CHEST
r
BLEACH OR
BRIGHTENING
FACILITIES
ALTERNATE
PULP
DRYER
SEWER
PAPERMAKING
LEGEND:
——• MAIN PROCESS
SECONDARY PROCESS
PROCESS WASTE LINE
-------
Thermo-Mechanical
A. recent development in refiner groundwood is equipment in
which the chips are pre-softened with heat and refined under
pressure in the range of 110-130°C (230-266°F). This
process is called thermo-mechanical pulping. Pulp
properties, such as longer fibers, are developed which make
this pulp a suitable replacement for a percentage of the
more expensive chemical pulp added to newsprint furnish to
provide adequate strength (92). Thermo-mechanical pulping
(TMP) is relatively new to the U.S. and a number of mills
have installed TMP as part of their pulp production
capacity. One mill recently started production which
produces tissue products using exclusively TMP. At the end
of 1975, it was reported that a total of 15 mills in the
U.S. were using TMP with a total TMP production of 2041
kg/kkg (2250 tons/day) (37) (306).
Cold Soda
In the production of cold soda pulp, chips are soaked either
at atmospheric pressure for two hours or under forced
pressure for shorter periods of time in liquor containing 20
to 40 mg/1 of caustic soda (2). The caustic expended varies
from two to 10 percent of the weight of the wood depending
on the wood species used and the pulp quality desired. The
liquor is recycled after fortification. Subsequent
separation of chips and liquor may be accomplished by
gravity or screw or roll presses may be employed. The
treated chips are then handled in a manner similar to that
used in manufacturing refiner groundwood (2)(3).
Chemi-Groundwood
The liquor used in chemi-groundwood pulping contains from 60
to 180 mg/1 of sodium sulfite buffered with one-sixth to a
third that amount of soda ash. Hardwood billets are first
impregnated with the liquor and then cooked for periods
ranging from a half hour to six hours at a maximum
temperature of 135 to 150°C (278-302°F) (2). This is
followed by grinding on stones under operating conditions
very similar to those of stone groundwood. This pulp is
stronger than conventional groundwood (11).
50
-------
Bleaching of Mechanical Pulp
While mechanical pulps have many desirable qualities for the
manufacture of low-cost papers, they are not naturally
sufficiently bright for the better grades (2). Too, the
brightness varies with the characteristics of the wood raw
material. For example, northeastern spruce and balsam will
generally produce a groundwood pulp in the brightness range
of 57 to 65 units while the pulps from west coast species
such as western hemlock range in the low 50*s. Thus,
bleaching is undertaken when necessary to satisfy the
demands of various end products.
The most common bleaching agents used for stone and refiner
groundwood are hydrosulfites and peroxides, and, in some
cases, both are used sequentially as shown in Figure 9.
Hydrosulfite systems can improve brightness by as much as
eight to 12 standard brightness units in a single stage
operation and up to 15 to 20 units in a two stage operation
with peroxide (2) . Peroxide alone has capabilities in the
range of eight to 12 or more units.
Bleaching with Peroxides
In peroxide bleaching, hydrogen peroxide is generally used
although sodium peroxide is sometimes employed (2) (10). A
solution of from 0.5 to 1.5 percent hydrogen peroxide or its
oxygen equivalent of sodium peroxide is applied to the pulp.
Frequently a small amount of magnesium sulfate — 0,24 to
0.48 gm/1 (1 to 2 lb/500 gal) of bleach solution -is used
for stabilization purposes. The pH of the pulp is first
adjusted to 10.5 with caustic soda which requires from 1.0
to 3.0 percent NaOH. Sodium silicate or sulfamic acid
sometimes replaces the caustic soda since they are capable
of sequestering metallic ions which catalyze peroxide
decomposition or discolor the product. Groundwood pulp is
generally bleached with peroxide at between 38 and 49°C (100
and 120°F). consistencies of bleaching range from four to
35 percent. The pulp is usually subsequently neutralized
with sulfur dioxide to prevent reversion.
In some instances, refiner groundwood is subjected to
refiner bleaching — i.e., a solution of peroxide is added
to the disc refiner employed for fiberizing. The bleaching
reaction thus begins while the pulp is refined and is
subsequently completed after discharge by maintaining the
pulp at discharge temperature, 77 to 93°C (170 to 200°F),
for about 15 minutes (2) .
51
-------
FIGURE 9
BRIGHTENING AND BLEACHING GROUNDWOOD
AND COLD SODA PULPS
PROCESS FLOW DIAGRAM
CAUSTIC
SODA
SULFUR
DIOXIDE
HYDROSULFITE
STOCK
CHEST
«
„
*
MIXER
I
,
PEROXIDE
TOWER
J
1
,
NEUTRALIZATION
TANK
MIXER
PEROXIDE
PROCESS
WATER
STEAM
HYOROSULFITE
TOWER
ALTERNATE
PULP
DRYER
BLEACHED
STOCK
CHEST
PAPERMAKING
LEGEND'-
MAIN PROCESS
SECONDARY PROCESS
-------
Some mills mix nodulated (pressed and shredded) pulp with
sodium silicate and hydrogen peroxide in tank cars or truck
tankers utilizing the tankage in transit as a reaction
vessel for the bleaching operation.
Peroxide solutions are prepared at the mill by batch or
continuous methods, and may contain either hydrogen or
sodium peroxide or both. Epsom salts, sodium silicate,
sodium and/or hydrogen peroxide is replaced by caustic soda
(2). In the case of a sodium peroxide solution, sulfuric
acid is used to replace the hydrogen peroxide.
Bleaching with Hydrosulfites
The brightening of groundwood pulp with hydrosulfites began
on the Pacific Coast. The process was introduced for the
production of newsprint, by Dr. Hirshkind of the Great-
Western Electro Chemical Company in the 1930's. Since this
early application, hydrosulfite use has expanded to include
the bleaching of groundwood pulp for all types of products.
Hydrosulfites have not found much use in the bleaching of
chemical pulps because the organic materials that
hydrosulfites react with are removed during cooking.
Hydrosulfites - more properly known as dithionites - are
well known reducing agents. There are two major
hydrosulfite salts used, zinc and sodium. Several methods
for their utilization in a bleaching system exist. The
selections of a hydrosulfite and the system parameters are
dependent on the degree of brightness desired and species
being bleached.
Process Variables
The effectiveness of hydrosulfite bleaching depends on the
following process variables: 1) wood species and quality, 2)
chemical treatments, 3) point of application, 4)
temperature, and 5) pH. Pulp consistency is sometimes
considered a process variable, but under normal conditions
deviations have a negligible effect on system operation
(330).
Bleaching with zinc hydrosulfite was originally applied to
groundwood from western hemlock and balsam fir. As use of
the process spread to other parts of the country, it became
apparent that brightening levels were dependent on the type
and quality of wood used. Bleaching tests of aspen
groundwood at the Kimberly Clark Corporation, Kimberly,
Wisconsin, showed that extended storage, as well as rot,
surface defects, knots and dirt decrease possible brightness
53
-------
gains (331). Tests with different species of wood have also
shown differences in respective brightness levels attained
(332).
Hydrosulfite application involves selection of the
appropriate salt. Previously, zinc hydrosulfite was used
most often; however, zinc discharge limitations have
encouraged a conversion to sodium hydrosulfite. The
combination of a hydrosulfite and peroxide in a multistage
bleach system is another possible application that will be
discussed in greater detail.
The addition of sequestering agents to reduce the effect of
metal ions in the pulp has been used as a pretreatment to
zinc hydrosulfite bleaching. The presence of metallic ions,
particularly iron, is thought to decrease possible
brightness gains and increase the amount of color reversal
as well as the amount of bleach used. Yankowski reported
that the addition of sodium tripolyphosphate had no effect
on initial brightness; however, EDTA was found to retard
brightness loss (333). Barton noted an increased level of
initial brightness with sodium tripolyphosphate, but could
only justify its use with zinc hydrosulfite concentrations
in excess of 6.5 kg/kkg (13 Ib/ton) (334). The use of
complexing agents must be evaluated in terms of the desired
degree of brightness and the level of contamination of the
pulp and process water (2). This indicates reasons for
varying types and amounts of hydrosulfite used in different
mills.
Several items affect the bleaching process, two of these are
described below.
1. Temperature
Temperature has a considerable effect on the degree of
consumption of zinc hydrosulfite and the time required
to achieve desired levels of brightness. Barton showed
that for concentrations below 7.5 kg/kkg (15 Ib/ton) of
hydrosulfite the effect of temperature is greatly
diminished. He concluded from this that the use of
steam to increase reaction temperature cannot be
justified unless a hydrosulfite concentration in excess
of 4 kg/kkg (8 Ib/ton) is to be used (334). There
appears to be a period of maximum brightness for each
temperature. If the stock is held at an elevated
temperature beyond this optimum time period, brightness
reductions will be experienced (332).
54
-------
Operating temperatures as low as 100°F with reaction
times of 6 hours have been used to achieve a maximum
response (333). Most bleach systems, however, utiliz?
temperatures in the range of 130-160°F and reaction
times of 1-2 hours (332r 331, 335).
2. p_H
Tests show zinc hydrosulfite to be most effective when
used in the pH range of 4.5-6.0, with an optimum value
at 5.6 (333r 334, 335, 336). Optimum pH, however, is
dependent on the quantity of the bleaching agent being
added. Lower pH values require smaller amounts of zinc
hydrosulfite, but below a pH of 4.5 corrosion becomes
the limiting factor (334) . Although there exists an
optimum, adjustment of the stock pH will not yield a
sufficient increase in brightness to justify the cost in
most cases. The only exception being if the pH is below
4.0 (335).
Description of Process
There are two basic methods of single-stage hydrosulfite
bleaching - hydrosulfite addition at the grinders or
refiners and after the deckers. These two processes along
with pulp washing and multistage bleaching with hydrosulfite
and peroxide will be discussed.
The major requirements for successful addition of
hydrosulfite to the pulp are that it be done rapidly,
thoroughly and in the absence of oxygen. If this cannot be
accomplished, substantial reductions in brightness attained
will occur (2, 334) requiring increased bleach usage. It is
also important that consideration for the process variables
already discussed be taken to insure maximum brightening.
In bleach treatment following the grinders or refiners, pulp
flowing from the receiving chest is screened to remove large
shives. Zinc hydrosulfite is added and mixed by pumping,
and the stock proceeds to the retention chests. Since the
temperature of the pulp leaving the chest is in the range of
130-140°F, conditions are ideal for good hydrosulfite
consumption without steam addition. The temperature and
consistency of the pulp following the grinder is especially
well suited to the application of low hydrosulfite
concentrations and short detention times (332, 337). In
most cases, hydrosulfite addition following the grinders is
found in the production of low brightness pulp such as that
used in the manufacture of newsprint.
55
-------
HycJrosulfite addition following the deckers is incorporated
when a higher degree of bleaching is desired. Chemical
concentrations of 1 to 2 percent and detention times of 1 to
; hours are necessary to achieve the brightness levels
desired. Since normal temperatures range from 120-1UO°F,
increasing the temperature with steam will give more
complete consumption of the hydrosulfite. In recent years,
however, many requirements for certain levels of brightness
have been lowered. This is because of an increased demand
for groundwood pulp for coated paper production. Coated
paper pulp can be several points lower initially than that
for filled sheets of the same brightness (33U). Therefore,
the need to increase temperatures has also been reduced. If
bleaching takes place following the deckers, washing of the
pulp can be done immediately before it passes to the paper
machine. This minimizes mill process discoloration and
increases bleaching effectiveness (332).
Multistage bleaching of groundwood is currently being used
to achieve brightness increases of 12-16 points. The two-
stage system most commonly employed is composed of peroxide
bleaching followed by hydrosulfite application. As the
brightness of the first stage approaches 80 units (G.E.),
the response of the pulp to the hydrosulfite stage is
greatly reduced. For a total brightness increase of 14 to
15 points, an increase of 10 points can be expected from the
first peroxide stage, employing a medium density application
of 2.5 percent peroxide and 1 to 5 points from the second
stage at a low density application of 0.8 percent
hydrosulfite (338). Richardson reports data concerning
brightness increases for various strengths of peroxides and
hydrosulfites for a two-stage system and for a three-stage
hydrosulfite-peroxide-hydrosulfite system (331).
Washing of hydrosulfite bleached pulp is not necessarily a
required procedure. It is practiced primarily to reduce the
corrosive effect of the spent liquor. Low pHfs promote the
decomposition of hydrosulfite into the thiosulfate ion,
which increases the corrosive effect of white water (2).
Barton and Atwood report that if zinc hydrosulfite is used
with correct procedures, corrosion is not a problem and
washing is not necessary (335). Washing was viewed as
essential, however, for the protection of equipment in
another operation (332). The impact of washing on color
reversal has not been conclusively determined, but it
appears small.
56
-------
Type of Hydrosulfite Used
The effectiveness of sodium and zinc hydrosulfite for
bleaching groundwood pulp is equivalent in many applications
(335, 337). Because the reactive component of zinc
hydrosulfite (ZnSK>4) and sodium hydrosulfite (Na2S.2O4.) is
the S2!O4_ radical, an equivalency of 1 Ib sodium hydrosulfite
to 1.11 Ibs zinc hydrosulfite exists (2). However, a
difference in visual color has been noted in many
applications with the zinc hydrosulfite producing a blue-
white color and the sodium hydrosulfite a yellow-white
color, both at the same reflectance brightness. For this
reason, zinc hydrosulfite has been preferred in many
operations. Masak, however, experienced considerably better
results with sodium hydrosulfite for the bleaching of aspen
groundwood, as indicated by Table 13 (331).
TABLE 13
COMPARISON OF BLEACHING AGENTS FOR ASPEN GROUNDWOOD
Zinc Hydro Sodium Hydro
Bleaching Brightness Gain 3.16 3.79
Hydrosulfite Per Ton, Lb 9.95 4.74
Hydro/Ton/Point Gained, Lb 3.15 1.24
The following is a comparison of sodium hydrosulfite versus
zinc hydrosulfite for bleaching groundwood pulp:
1. Less chemical is required to accomplish bleaching when
using sodium hydrosulfite (2).
2. Sodium hydrosulfite is more effective than zinc
hydrosulfite following a peroxide bleaching stage (339).
3. Zinc hydrosulfite is not stable above a pH of 8 and only
works well from pH 4.5 to 6.0, while sodium hydrosulfite
is stable up to pH 11.0 but its effectiveness is greatly
reduced below pH 6.0 (2, 335).
4. Sodium hydrosulfite is not as corrosive as zinc
hydrosulfite (2).
5. Use of zinc hydrosulfite may require additional waste
water treatment to reduce zinc concentrations, however,
using sodium hydrosulfite will not necessitate
additional treatment steps.
57
-------
6. Zinc hydrosulfite provides improved bleaching capability
with increases in temperature of up to 200°F.
7. Zinc hydrosulfite provides greater solution and bleach
stability than sodium hydrosulfite, particularly at high
temperatures and low pH's (2, 337).
8. Zinc hydrosulfite provides a degree of protection from
bacterial attack and acts as a deterrent to slime growth
(2, 332, 337).
9. Zinc hydrosulfite may be prepared on site from zinc dust
and sulfur dioxide, while sodium hydrosulfite presents
some problems with storage and handling because it can
oxidize when moistened (335).
10. As temperatures increase, the alkaline reaction produces
a yellowness in the bleached pulp when sodium
hydrosulfite is used as the bleaching chemical (332).
The final choice of which salt to use in commercial
applications will depend on product, economics,
environmental impact, and the particular system employed in
bleaching the pulp (337).
Chemical Pulping of Wood
As the term implies, the energy used in chemical pulping to
separate cellulose fibers from other wood components derives
from chemical application. Wood is cooked in batch or
continuous digesters, large pressure vessels, with solutions
of various chemicals to the point at which non-cellulosic
constitutents are dissolved and the fibers can be liberated
by blowing the digester, or by jets of dilution water in the
blow pit (3). Other than a simple "opener" device used in
conjunction with the blowing of some high lignin content
sulfite pulps (2) , no subsequent mechanical devices are
necessary.
Thus, chemical pulping methods are described as "full cook"
processes. This differentiates them from the mechanical
operations described above and semi-chemical pulping, which
employ both chemical pretreatment and mechanical energy in
varying relative degrees of strength.
In some cases in chemical pulping, screenings (incompletely
pulped wood fragments) may be refined and returned to the
process to increase yield. However, as long as the entire
stock is not subject to refining, the process is considered
chemical (3).
58
-------
The range of pulp yields obtained from chemical processes
are lower than those of mechanical and semi-chemical
pulping. In general, the sulfite papermaking pulp range is
from 45-60 percent, and kraft and soda, 40-55 percent. The
yield range for dissolving pulps is from 30-40 percent.
Softwoods are the primary fiber raw material of the sulfite
process, and both soft and hardwood are used in kraft and
soda pulping.
Sulfite
The sulfite process is used to make two distinctly different
types of pulp — papermaking grades and dissolving grades.
The basic process is the same for both, although there are
significant differences in cooking temperatures, strength of
chemical application, and bleaching practices. The
following discussion of sulfite pulping is generally
applicable to both. The major differences in its
application to dissolving pulp are noted at the end of this
discussion, and the variations in bleaching are covered
under "Bleaching of Chemical Pulp."
In the sulfite process, wood chips are cooked with acidic
solutions of the sulfites of calcium, magnesium, ammonia, or
sodium. The cooking liquor is manufactured at the mill from
purchased and recovered chemicals(4).
Sulfurous acid is prepared by absorbing sulfur dioxide in
water. Sulfur dioxide is made at the mill by burning sulfur
or is purchased in liquid form either of which is
supplemented by that returned to process from the sulfur
dioxide recovery system.
In calcium base mills, calcium is supplied either in the
form of calcium carbonate or calcium oxide; the base is
reacted with sulfurous acid and is not usually recovered
from the spent liquor. In ammonia base mills, aqua ammonia
is reacted with sulfurous acid. If the chemical is
purchased in the anhydrous form, it is first put into solu-
tion. Ammonia, too, is not recovered. Magnesium oxide and
caustic soda are purchased as make-up base for the magnesium
and sodium base recovery systems which retain about 90
percent of the base in the system (17) through recovery.
When cooking is completed, the pulp is blown into a blow
tank. It is then delivered to multi-stage vacuum washers on
which countercurrent washing separates the spent liquor from
the pulp. In some cases, blow pits rather than tanks are
employed where the pulp is washed by diffusion of wash water
59
-------
through the pulp mass. It is possible to recover 95 percent
of the liquor solids by vacuum washing, but the limit is
about 85 percent from displacement washing in blow pits. A
15 percent liquor concentration is obtainable by vacuum
washing while the highest solids concentration attainable by
blow-pit washing is about 10 percent (5). Off-gases are
passed to an absorption system for recovery of their sulfur
dioxide content (17). After washing, the pulp is diluted,
screened, centrifugally cleaned, and deckered to the desired
stock chest consistency for bleaching. A process diagram is
presented in Figure 10.
The weak red liquor separated from the pulp is evaporated to
a consistency of 50 to 60 percent solids which is suitable
for burning (18). Because of scaling problems, special
evaporation units of the switching type are required for
calcium base liquor. Also, forced feed evaporators must be
used for ammonia base liquor because of its high viscosity.
In the magnesium base process, the ash produced on burning
the liquor is magnesium oxide which is recovered in cyclones
and returned to the liquor manufacturing section of the mill
(1) . The smelt obtained on burning sodium base liquor is
solidified and redissolved under controlled conditions so
that the soda ash and sodium sulfide present can be
separated by differential solubility. The sodium sulfide is
reacted with carbonic acid to form hydrogen sulfide which is
burned to produce sulfur dioxide. The latter is reacted
with the soda ash obtained from the smelt to form sodium
bisulfite cooking liquor, and the carbon dioxide produced is
employed in the sodium sulfide reaction (1)(19). Ammonia
base liquor is burned either in a typical recovery furnace
or a fluidized bed unit and sulfur dioxide is stripped from
the off-gases for use in the liquor preparation unit. A
process flow diagram of a magnesium base sulfite recovery
system is presented in Figure 11.
In the preparation of sulfite dissolving pulps, the wood is
cooked at a higher temperature than for papergrade pulps
(159) . Cooking is continued until most of the lignin and
part of the cellulose are dissolved whereas in papermaking
pulps only the lignin is dissolved (340). The resulting
spent liquor thus has a higher solids content when burned.
In addition to screening to remove bark and wood particles
after the pulp is washed, it is often sent through special
"side-hill" screens for thickening and to separate resinous
materials (159) (180) .
60
-------
FIGURE 10
SULFITE PULP MILL
PROCESS FLOW DIAGRAM
WOOD CHIPS
1
RED LIQUOR
SYSTEM
CONDENSATE
.,
ALTERNATE
1
PULP DRYER
DEBARKED
ROUNDWOOD
1
J
H
*
DIGESTERS
i
pi nW TANK
1 *
J
1 L^
1
SCREENS
,
1
STOCK
CHEST
1
1
BLEACH
PLANT
PAPERMAKING
SULFUR
BURNER
i
+ GAS
% VI'
- OnnKING h . .n.^.i. . .JM,
LIQUOR ABSORHIION
i_ i wisvsn TOWFR
""' ~ STORAGE | '' iwficn
RECOVERY ' f "
CA" S02
GAS * scnUDDCn « LIQUOR
* oOKUbBCR « BASE
p *
1 j
* — ' PROCESS _J
- WATFR
* 1
1
-ii *.
7
S
-------
FIGURE 11
MAGNESIUM BASE SULFiTE RECOVERY SYSTEM
PROCESS FLOW DIAGRAM
PROCESS
WATER
OFF
| *GAS
So2 * J
SULFUROUS
ACID
RECOVERY
WEAK
RED LIQUOR
FROM WASHERS
1
1 STRONG
LIQUOR
CONTACT
EVAPORATORS
I
I
MAGNESIUM
OXIDE
RECOVERY
I —
COOKING
PREPARATION
CONDENSATE
_ ^
RED
FURNACE
J
i
SEWER
- Mgo LEGEND:
«"™™^~ MAIN PROCESS
SECONDARY PROCESS
PROCESS WASTE LINE
62
-------
Bleached Kraft
Both paper grades and dissolving pulp are also made by the
kraft process. Here, too, the fundamentals of the process
are the same for both but there are variations in details as
noted below.
Wood chips are cooked in a solution consisting primarily of
a mixture of caustic soda and sodium sulfide which is known
as white liquor. The pulp characteristics desired determine
the percentage of sulfide used in the liquor. Both batch
and continuous digesters are employed although the latter
are more common in operations in which only one grade of
pulp is cooked (2) .
In order to make kraft pulps more amenable to bleaching, the
chips are sometimes steamed in the digester for a short
period prior to the addition of the cooking liquor (2) (3).
This is called pre-hydrolysis and is a necessary adjunct to
the production of dissolving pulps by the kraft process.
In this step, the chips are loaded into the digester which
is then partially or totally filled with water and the whole
mass is heated, usually by means of direct steam injection.
As the temperature rises, wood acids are released and the pH
drops rapidly from approximately 7.0 to 3.5 (189). The
acidic conditions degrade and solubilize hemicellulose
molecules in the wood thus removing materials detrimental to
the cooking process. After about two hours the kraft liquor
is introduced to start the cooking stage (189). Kraft
dissolving pulp is discussed further under "Bleaching of
Chemical Pulp."
Because the chemical cost is high, chemical recovery has
always been accessory to the kraft process. This is
accomplished by burning the spent liquor and in so doing
sufficient heat is generated to sustain the pulping process.
The recovery system and its role in the preparation of
cooking liquor are described in ensuing paragraphs.
When cooking is completed the chips are "blown" from the
digester to a tank where they separate into fibers. Steam
from the tank goes to an accumulator for heating process
water. Drainings are frequently returned to the white
liquor used in succeeding cooks.
The pulp is transferred, along with the "spent cooking
liquor" (called "black liquor"), to a "brown-stock" chest,
or tank, and from there to vacuum drum washers or continuous
diffusers where the spent liquor is separated by
63
-------
counter-current washing. In older mills, the pulp is "blown"
directly to the diffusers from the digester.
Chemical recovery necessitates a high degree of liquor
separation with as little dilution as is possible to
minimize heat requirements of evaporation (2)(20) — i.e., a
high percentage of solids must be retained in the liquor in
high concentration. Thus, three stages of washing are
common and, in some cases, four are used. In some newer
installations a combination of vacuum washers and diffusers
is employed (21). When continuous digesters are equipped
for internal diffusion washing the pulp requires only one or
two stages of external washing.
After washing, the pulp is diluted and screened to remove
knots, incompletely cooked chips, resin particles, etc. It
is then deckered to a consistency suitable for bleaching.
In modern bleached kraft mills, a decker is used which has
been adapted to provide a final wash shower which enhances
bleaching performance.
The kraft pulping process is illustrated in Figure 12.
The liquor separated from the pulp in the washing operation
is called "weak black liquor" and contains about 10 to 14
percent solids. In addition to the inorganic cooking
chemicals, it contains organic wood constituents separated
in the pulping process. The weak black liquor is
concentrated to about 40 to 45 percent solids in long tube
multiple effect evaporators and the resulting viscous mass
is called "strong black liquor." This is then concentrated
further to a consistency of 60 to 65 percent solids in the
recovery furnace contact evaporator or in a concentrator.
Cooking chemicals lost in pulping and washing are replaced
with make-up chemical, usually sodium sulfate, or a residue
with a high content of this salt (5). Acid sludge from tall
oil treatment, neutral sulfite semichemical (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 compounds are converted to soda ash and
sulfates to sulfides on the floor or reducing section of the
furnace. The molten smelt of salts is dissolved in water to
form "green liquor." This is clarified by sedimentation and
64
-------
FIGURE 12
BLEACHED KRAFT PULPING
PROCESS FLOW DIAGRAM
OFF
GAS
PULP DRYER
—— MAIN PROCESS
SECONDARY PROCESS
PROCESS WASTE LINE
65
-------
then causticized with lime to convert the soda ash to
caustic soda. After causticizing, the combined sodium
sulfide-caustic soda 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 the white liquor is
stored for use in the pulping process.
The lime mud (calcium carbonate) obtained from settling this
white liquor is washed and dewatered on rotary vacuum
filters or centrifuges and burned in rotary or fluidized bed
kilns to form quick lime. This is hydrated with green
liquor in slakers for reintroduction to the recovery cycle.
Equations describing the chemical recovery process are shown
in Figure 13. (5) The kraft recovery system is illustrated
in Figure 14.
Soda
The only major difference today between the soda and kraft
processes and their recovery systems is that sulfur is
present in kraft liquor and because of this black liquor
oxidation is practiced at a number of kraft mills (3). All
the recovery systems of both are designed to burn all the
organic matter present in the black liquor rather than
producing black ash as in the old soda process (30).
In the soda process wood chips are cooked in a solution of
caustic soda containing 6.1 to 6.6 pounds of active alkali
per cubic foot of liquor. When pulping is complete the
contents of the digester are blown into a tank. Exhaust
steam passes through a cyclone to remove entrained black
liquor which is sent to the recovery plant. This steam and
that contained in the relief gases is condensed in a heat
exchanger used for heating process water before entering the
atmosphere. Knots are removed from the pulp which is then
washed on countercurrent drum washers generally in three
stages. The pulp is then diluted, screened, and deckered to
stock chest consistency.
The weak black liquor from the washers is concentrated to 40
percent solids content in long tube multiple effect
evaporators and then to about 65 percent in a recovery
furnace stack evaporator. The liquor is then burned in the
recovery boiler. The molten ash, which consists almost
entirely of sodium carbonate, is dissolved in weak wash
water and the make-up chemical — purchased and recovered
soda ash -- is added to form green liquor. Also, the make-
up chemical can be sodium hydroxide to the white liquor
66
-------
FIGURE 13
KRAFT CHEMICAL RECOVERY PROCESS
Burning:
Na2S04 + 2 C - »»Na2S + 2C02
Causticizing:
Na2C03 + Ca (OH)2 2NaOH + CaC03
Reburning: (of mud)
CaC03 - ^ CaO + C02
Slaking:
CaO + H20 -
67
-------
FIGURE 14
KRAFT RECOVERY SYSTEM PROCESS FLOW DIAGRAM
WEAK BLK. LIQUOR
FROM BROWNSTOCX
WASHERS
1 ,
i
CONDENSATE
TALL OIL
RECOVERY
r^
ELECTROSTATIC
PRECIPITATOR
i
GAS
SALT CAKE
r*
EVAPORATORS
1 1
\
STRONG BLACK
LIQUOR
STORAGE TANK
, 1
\
RECOVERY
FURNACE
1
I
DISSOLVING
TANK
STEAM
'
'
BLACK
LIQUOR
OXIDATION
i
CON!
EVAPO
<
1
FACT
RATOR
•
MIX TANK
REUSE
OR
SEWER
PROCESS
WATER
r-+0fF
^ GAS
SCRUBBER
i
GAS
LIME KILN
1
t
LIME
MUD
FILTER
1
«-
U
NC
I
ER-
FLOW
GREEN
LIQUOR
CLARIFIER
UNDER- DREGS
FLOW* WASHER
1
SLAKER
1
CAUSTICIZING
1
WHITE
LIQUOR
CLARIFIER
GRITS
DISPOSAL
MAIN PROCESS
SECONDARY PROCESS
PROCESS WASTE LINE
68
-------
rather than sodium carbonate to the green liquor. The green
liquor is clarified and causticized with lime to convert the
sodium carbonate to sodium hydroxide. The lime mud is
settled and filtered from the solution which is now
designated a white liquor. This is filtered through a
pressure filter and stored for use in the digesters. Lime
mud is dried and burned to calcium oxide which is slaked and
used again for causticizing. The kiln is equipped with a
venturi scrubber for dust collection which generally uses
weak wash from the causticizing system. This is returned to
the process carrying recovered lime and some soda (21).
The soda pulping process is identical to that of kraft
pulping illustrated in Figure 12. The reactions involved
are shown in Figure 15.
Bleaching of Chemical Pulp
The chemicals most commonly employed for bleaching chemical
pulps are chlorine, calcium or sodium hypochlorite, and
chlorine dioxide. Alkalies such as caustic soda and calcium
hydroxide are used for extracting chlorinated reaction
products from treated pulp. In some instances, hydrogen
peroxide or sodium peroxide or peroxyacetic acid are used in
the finishing stages of bleaching (22). Sulfur dioxide or
sodium sulfite (1)(8) can be used as neutralizing and anti-
chlor reagents and in some instances to stabilize pulp
brightness. However, the chlorine compounds and alkalis are
the most commonly applied chemicals.
Chlorine and caustic soda are either purchased in liquid
form or, in rare cases, manufactured at the mill by
electrolysis of sodium chloride. Hypochlorites are
generally manufactured on site by treatment of milk of lime
or caustic soda with chlorine, strengths produced vary with
intended use since this chemical is used not only for
bleaching, but, in the case of dissolving pulps, to control
the ultimate pulp viscosity.
Chlorine dioxide, because of its instability, is
manufactured at mills which use it by one of four methods.
These arc the Mathieson process, a modification thereof, the
R-2 process, and the Solvay process. They all employ sodium
chlorate and sulfuric acid. Sulfur dioxide is also used in
both the Mathieson processes, and sodium chloride is added
in the modified Mathieson method and R-2 technique.
Methanol is substituted for sulfur dioxide in the Solvay
process (8) (2U) .
69
-------
FIGURE 15
CHEMICAL REACTION INVOLVED IN THE
SODA PULP MILL RECOVERY SYSTEM
Liquor
Combustion
Causticizing
Calcining
Slaking
R Na + A
C + 02
C02 + Na20
Na2C03 + Ca(OH)2—*-
CaC03 + A —*- CaO
C + Na20
+ CaC03 1
CaO + H20
Ca(OH)2
70
-------
Other bleaching chemicals are purchased in their common form
and treating solutions are prepared according to process
needs. These are employed in relatively small quantities as
compared to the major bleaching agents.
Bleaching is ordinarily performed in a number of stages.
This is done to preserve the strength of the pulp by
avoiding excessively rigorous chemical treatment and to
control consistency and temperature in accordance with the
demands of the particular treatment applied. Each stage
consists of a reaction tower in which the pulp is retained
in contact with a particular chemical agent for the optimum
period of time. It is then washed on vacuum washers or
diffusers and discharged to the next stage. Consistency in
the reactors generally ranges from 3.5 to 12 percent and
temperatures range from ambient in the chlorination stage,
to 60°C (1UO°F) in extraction stages, 35°C (95°F) in hypo-
chlorite stages, and 82.2°C (180°F) in chlorine dioxide
treatment.
The chemical concentrations employed depend upon the
consistency, the temperature, the number of stages, the
specific chemicals used, the species of wood from which the
pulp was produced, and the degree to which it was cooked, as
well as the quality of product desired. Three stages are
generally used in semibleached kraft operations and for
bleaching of sulfite paper grade pulps. Since kraft pulps
are dark in color, particularly when made from softwoods,
high-bright kraft pulps usually require more stages.
Normally five are used although some mills employ six or
more (25)(26). Three stages may be used for low-brightness
soda pulp and four stages for high brightness.
Table 14 shows the most common sequences used to bleach
kraft pulp to various degrees of brightness.
For high bleach kraft pulp, the CEDED sequence appears to be
favored. Ten mills report using it against 14 employing
other sequences, most different from the other. CHHD is
used by a few mills as a means of reducing color in the
bleaching effluent. Mills which partially bleach kraft most
commonly employ a CED sequence while a few either modify
this procedure or add another hypochlorite stage. The CEH
sequence is frequently used for bleaching paper grade
sulfite pulps, although additional or other stages may be
used by mills producing several different grades. CEH is
also used by one mill for semi-bleached soda pulp; one soda
mill employs CEHP for fully bleached pulp and another uses
CEHD.
71
-------
A typical four stage kraft bleach plant is shown in Figure
16, and Figure 17 illustrates a three stage sulfite
bleachery.
Oxygen Bleaching
Oxygen bleaching is a very recent development and is
presently used in only six mills throughout the world.
Three of these are in Sweden, where the process was
initiated, and there is one each in France (122), South
Africa (40), and the U.S.
The U.S. mill bleaches kraft pulp with a three stage
bleaching sequence, D/C OD, which is illustrated in Figure
18 (187) (188). It achieves a brightness equivalent to that
obtained by the more costly five and six stage sequences
such as CEDED and CEHDED. The pulp is being used in nearly
every paper grade and provides quality equal to that of
conventionally bleached pulp. It is also reported to be
less susceptible to brightness reversion.
Subsequent to the C102/C12 treatment, SO2 is added to the
stock flow and the pulp is then pressed to a consistency of
27 to 52 percent. It next receives a five percent caustic
solution. When it enters the oxygen reactor the high
consistency pulp is fluffed to increase fiber exposure to
the oxygen atmosphere (177). It is reacted at 121°C (260°F)
for 20-30 minutes with oxygen produced on-site from the
atmosphere (23). A final Clo^ stage completes the sequence.
Another oxygen bleaching stage has been in use in a Swedish
kraft mill since November, 1973. In contrast to the
sequence of the U.S. mill, the process there employs the
oxygen stage first in an OC/DEDED sequence (140) (Figure
19) . The pulp is of high quality with brightness in excess
of 92, and has the same physical strength as pulp previously
bleached by a C/DEDED sequence.
The advantages of oxygen bleaching in relation to pollution
control are that the bleach plant waste waters can be
recycled to the pulp mill where they can be evaporated and
burned along with the black liquor. However, the
introduction of additional inorganic and organic loads from
the oxygen bleaching operations can only be accomplished if
adequate evaporator and recovery furnace capacity are
available. Since most of the existing mills were designed
with recovery systems designed to handle only black liquor,
the necessary capacity is sometimes unavailable, and the
additional capacity can be made available either through
installation of the necessary capacity for evaporation and
72
-------
FIGURE 16
FOUR STAGE KRAFT PULP BLEACH PLANT PROCESS FLOW DIAGRAM
L
P
CHLORINE
STEAM
/•
v/
r»
\_
L
r
CAUSTIC
TOWER
1
WASHER
L
r
HYPOCHLORITE
TOWER
I
WASHER
L
j r
CHLORINE
SEAL PIT
1
CAUSTIC
SODA
CAUSTIC WASTE
SEAL PIT
1
HYPOCHLORITE
PREPARATION
CHLORINE
DIOXIDE
PREPARATION
PROCESS
WATER
PULP
DRYER
LEGEND:
^-^ MAIN PROCESS
SECONDARY PROCESS
PROCESS WASTE LINE
73
-------
FIGURE 17
THREE STAGE SULFITE PULP BLEACH PLANT
PROCESS FLOW DIAGRAM
PROCESS
WATER
STEAM
fr»
*.
BROWN
STOCK
CHEST
rL
T
CHLORINE
TOWER
J
1
WASHER
L
r
CAUSTIC
TOWER
L
I
WASHER
L
1
HYPOCHLORITE
TOWER
L
r
WASHER
1
CHLORINE
ACID WASTE
SEAL PIT
CAUSTIC
SODA
CAUSTIC
WASTE
SEAL PIT
HYPOCHLORITE
PREPARATION
SULFUR
DIOXIDE
^
1
I
jj
BLEACHED
STOCK
CHEST
r:
ALTERNATE
PULP
DRYER
PAPERMAKING
SEWER
LEGEND:
^—— MAIN PROCESS
SECONDARY PROCESS
PROCESS WASTE LINE
74
-------
FIGURE is
OXYGEN BLEACH PLANT AT SURVEYED MILL 124
PROCESS
WATER _r_
>
r>
*
BROWN
STOCK
CHEST
i CHLORINE
PREPARATION
CHLORINE
DIOXIDE
TOWER
CHLORINE
TOWERS
1, SULFUR
DIOXIDE
PRESS
ML CAUSTIC
*f SODA
MIXING
COLUMN
1
OXYGEN
REACTOR
1
BLOW TANK
1
WASHER
1 CHLORINE
PREPARATION
CHLORINE
DIOXIDE
TOWER
J
WASHER
1
PULP
STORAGE
-|
SULFUR
DIOXIDE
LE6E
•M^^H
~1
-J
*1
^j
^1
1
. _J
~
1
1
i
SEWER
ND:
• MAIN PROCESS
- SECONDARY PROCESS
- PROCESS WASTE LINE
75
-------
FIGURE 19
OXYGEN BLEACH PLANT AT SWEDISH MILL
BROWN
STOCK
CHEST
MIXING
TANK
OXYGEN
REACTOR
BLOW
TANK
TWO
STAGE
WASHERS
HIGH DENSITY
STORAGE TANK
CAUSTIC
TOWER
n
STEAM
CAUSTIC
SODA
OXYGEN
PROCESS
WATER
MIXING
TANK
1
CHLORINE
TOWER
I
WAS
HER
r
LI
CHLORINE
CHLORINE
DIOXIDE
PREPARATION
I.
r
CAUSTIC
SODA
r
WASHER
CHLORINE
DIOXIDE
TOWER
WASHER
CAUSTIC
TOWER
WASHER
CHLORINE
DIOXIDE
TOWER
WASHER
BLEACHED PULP
STOCK CHEST
SEWER
LEGEND:
| MAIN PROCESS
SECONDARY PROCESS
PROCESS WASTE LINE
76
-------
recovery or by reduction in the pulp production. One
company has estimated that a reduction in pulp production of
approximately five percent would be required to implement
oxygen bleaching using existing equipment (328).
77
-------
Table 1U
COMMON SEQUENCES USED TO BLEACH KRAFT PULP
TO VARIOUS DEGREES OF BRIGHTNESS
Range of Bleaching
G.E. Brightness sequence(See Table 8)
70 to 80 CEH
CEHH
80 to 85 CHEH
CIHEH
CC/HEHH
CED
85 to 92 CEHD
CHED
CEHDD
CC/H ED/H
CEDED
CEDHED
Steam and alkali (caustic soda, at present) are added to
pressed stock of approximately 35 percent consistency which
is reacted with oxygen, after fluffing, for 30 minutes at
95-100°C (203-212°F). In order to meet a requirement of
sulfur emission standards the caustic soda used in the "O"
stage can be reclaimed and used in the cooking liquor pre-
paration to reduce its sulfidity at a considerable cost
saving (140). This stage is followed by the remaining
stages of the sequence in conventional equipment.
Some experimental work has been done with ozone as a
bleaching agent. Since it is more a delignifying agent than
a bleaching agent (11), it could be used most effectively as
a first stage in bleaching. However, when large amounts of
ozone are charged in one stage, a dramatic drop in the
viscosity of the pulp occurs (11). This can be overcome
with the use of several stages although at considerable
cost. Also, the production capacity of existing ozone
generators is too small for bulk use of this chemical.
78
-------
DisplacementBleaching
Two U.S. companies are installing a new displacement
bleaching process which has been in pilot operation in
Finland. Bleaching chemicals are displaced through a pulp
mat rather than being conventionally mixed into the pulp
(185). Very rapid bleaching can be accomplished due to high
reaction rates. Filtrate withdrawal at one stage is
fortified with make-up chemical and reused (186). In the
first such system in this country, the bleaching tower will
be 15 feet in diameter and 80 feet in height (186). It will
accommodate four stages of bleaching, stacked in the tower
so that the unbleached pulp moves sequentially from bottom
to top as shown in Figure 20.
Bleaching of Dissolving Pulps
Dissolving pulps are always bleached, and, in addition,
usually must undergo one or more additional reactions such
as chemical purification, deresination, ash removal, etc.
Most of these steps are combined in a complex bleaching and
purification process (2) .
The actual bleaching for both sulfite and prehydrolysis-
kraft is accomplished by standard procedures as described
above. CEHD is used by some sulfite dissolving mills,
although others employ a five-stage process which may or may
not include a chlorine dioxide stage. The use of this
chemical, however, is indispensable for the production of
dissolving grades from kraft pulp.
The purpose of the caustic extraction stage in bleaching
dissolving sulfite pulps is somewhat different from its
function in bleaching sulfite paper grade pulps. In the
latter, this stage is used to remove partially bleached
material solubilized in the chlorination stage. In the
manufacture of dissolving pulp, the extraction stage is much
more drastic in terms of caustic concentrations and degree
of heat in order to dissolve a specific fraction of the
cellulose itself which is not suited to the manufacture of
rayon (159). Over 45 kg (100 Ib) of caustic may be added
per kkg (ton) of pulp and reaction temperatures exceed the
boiling point while only about 14 kg (30 Ib) of caustic
under warm conditions are required for paper grade pulp
(180). In dissolving pulp bleaching, this step dissolves
from 15 to 30 percent of the pulp, depending on the grade of
cellulose desired (340).
For kraft dissolving grades, the unbleached pulp is purified
in the bleach plant to remove all traces of lignin and
79
-------
FIGURE 20
PLANNED DISPLACEMENT BLEACH PLANT
AT SURVEYED MILL 12! (179)
BLEACHED PULP
STOCK CHEST
PROCESS
WATER
WEAK CAUSTIC
LIQUOR
CAUSTIC
SODA
r~
f
ALKALINE
WASTE TO
MILL OR SEWER
BROWN
STOCK
CHEST
h
1
t
J
__SECOND ClOp
STAjp:-^""1
{
SEC
"~EX-^R*
s-w
QND
iGE
J
__£IRS'T ClOo
STAGE--^*^"
i
r Fifbt
^^AGE
DISPLACEMENT
TOWER
WEAK CIO?
LIQUOR
1 t
J
WEAK CI02 +
LIQUOR 'J
i |
1
,, CHLORINE 1
PREPARATION |
i
*
SEWER
LEGEND:
MAIN PROCESS
PROCESS WASTE LINE
80
-------
hemicellulose. This is done by means of a five to eight
stage process, typically consisting of chlorination, caustic
extraction, hypochlorite bleaching, chlorine dioxide
bleaching, further caustic extraction followed by more
chlorine dioxide and hypochlorite. Lignin is removed by
chlorine and chlorine dioxide and hemicellulose by caustic
extraction (189) . The extreme hot alkaline extraction
conditions designed for sulfite dissolving, described above,
are not useful for the kraft dissolving process in which the
alpha cellulose level is determined largely by cooking
procedures (8).
Deinked Pulp
A variety of waste papers are deinked to make several grades
of pulp. Most waste paper used in this manner must be
sorted and carefully classified since 1) not all papers are
suitable for deinking; 2) certain types are desirable for
some types of reclaimed pulps and are not suitable for
others; and 3) papers which can be processed successfully by
one process could be troublesome if mixed with papers
requiring different treatment (2) .
Waste paper is preferably sorted at its source (homes,
offices, stores, factories, printers, or manufacturers of
paper products such as boxes, envelopes, etc.); otherwise it
must be sorted by the dealer, or at the mills. Sorting at
the source is becoming more common today for two reasons.
One, sorted waste papers bring higher prices both to the
generator and the dealer than mixed bales. Second, sorting
at the mill is an expensive hand operation.
Some mills are able to buy overruns of specific publications
which are uniform in character. This makes for a successful
operation since sorting is not required and the deinked
product is more uniform.
High groundwood content papers are deinked for use in tissue
or molded products, and for liner in board mills. These
papers are not as suitable for fine or printing paper
operations. Papers which contain plastics, latex, exotic
inks, and other non-dispersible materials cause difficulties
in deinking, degrade the product, or generate troubles on
the paper machine. Wet strength papers are given separate
treatment because of their resin content.
Details of the deinking process used to produce pulp for
fine papers depend upon the characteristics of the waste
paper, but the process consists primarily of an alkaline
cook to which dispersants, detergents, and solvents are
81
-------
added. The process is essentially a laundering operation in
which the sizes, any coating binder, and the pigment vehicle
in the ink are dissolved or dispersed and the ink pigment
released, along with filler and coating agents such as clay,
calcium carbonate, and titanium dioxide. Adhesives such as
starch and glue are also dissolved and dispersed. The
process is essentially the same in all mills except that
somewhat different process units may be used from a variety
of specific pieces of equipment. The equipment and process
are described in detail in a TAPPI monograph (27).
The waste paper is generally cooked in a pulper at a
consistency of between five and eight percent and a
temperature ranging from 80° to 99°C (180° to 210°F).
Cooking time is determined generally by examination of a
sample from the pulper. During this step a trash boot and a
ragger may be used to remove trash, rags, rope, wire, etc.
The stock is then usually screened at about one to two
percent consistency, after which it is ready for cleaning.
This is accomplished by passing the stock at about 0.5
percent consistency through centri-cleaners and fine
screens. Generally countercurrent washing is employed on
washers of various types. Some mills employ flotation for
separating the fiber from the undesirable materials and
others use various kinds of deckering or thickening
equipment. Fiber leaves the washers and is delivered to a
stock chest at six to 15 percent.
Deinking practices in a tissue or mglded pulp mill do not
vary appreciably from the above. However, cooking
temperatures for papers high in groundwood content are
generally lower — 38° to 71°C (100° to 160°F) with a pH
below 10. In addition, sodium peroxide is frequently added
to the cooking liquor since its bleaching action tends to
prevent browning of the pulp.
A considerable shrinkage of the raw stock occurs in deinking
because of the filler and coating materials washed from it
along with large quantities of fiber fines when appreciable
groundwood is present. The shrinkage for common grades of
waste paper is shown in Table 15 (27).
Newsprint is deinked by a proprietary process employing a
special detergent. The pulp produced is suitable for
conversion on high-speed newsprint paper machines with the
addition of little, if any, long fiber stock and may not
require bleaching. Shrinkage is reported to run around 15
percent.
82
-------
In some non-deinking operations considerable quantities of
books, envelope cuttings, and flyleaf shavings, and similar
unprinted scrap is repulped and washed free of fillers,
adhesives, and sizing materials. Although ink removal is
not involved, shrinkage and attendant sewer losses from such
operations are similar to those from deinking.
At some paper mills relatively small amounts of selected
kinds of waste paper are deinked from time to time for use
in furnishes employed in the production of particular
specialties. In such cases, almost the entire operation,
including bleaching, is carried out in Hollander beaters
(28). This may be the case also with the reclamation of
fiber for use as liner in board mills.
Table 15
SAMPLES OF SHRINKAGE
OF VARIOUS TYPES OF PAPER
ON DEINKING
XAsh ^Shrinkage
Bond 2 10
Ledger 5 15
Offset 12 19
Book 20 3U
Gummed 10 40
Coated 25 U2
Coated 30 50
83
-------
Bleaching of Deinked Pulp
Deinked fibers consisting primarily of bleached chemical
pulp are bleached in one stage with chlorine or calcium or
sodium hypochlorite. From two to five percent of available
chlorine is commonly used. Consistencies of the pulp
bleached range from three to as high as 12 percent; tower
type bleaching is used for the higher consistencies. When
pulps containing considerable lignin are bleached after
deinking, the three-stage CED process commonly applied to
kraft and sulfite pulps is employed (6). In this process,
three percent of chlorine is applied to a dilute slurry of
the pulp at ambient temperature. The pulp is then thickened
and treated with caustic soda at 38°C (100°F) which is
followed by washing and treatment with hypochlorite. A
variety of equipment and variations of this process are in
use. Pulps high in groundwood are bleached by the methods
employed for groundwood alone and variations thereof
employing caustic soda, peroxides, and hydrosulfites.
Bleaching decreases the yield in the range of from 2.9 to
five percent (28) (8) .
A process flow diagram of a deinking operation with single
stage bleaching is presented in Figure 21 and a similar
diagram of a three stage bleaching system for deinked pulp
is shown in Figure 22.
Papermakinq
In stock preparation, pulp, either purchased or produced on
site, is resuspended in water to a consistency of four to
six percent. The stock is mechanically treated in beaters
or continuous refiners to "brush" or fray the individual
fibers to obtain the necessary matting which produces the
desired strength in the paper. This process also cuts the
fibers to some degree. In cases where good formation is de-
sired, such as fine papers, the stock is also pumped through
a Jordan which further cuts the fibers, with a minimum of
brushing, to the necessary length. The amount of brushing
and cutting varies with the type of pulp and the end product
requirements. In a few cases, no mechanical treatment is
needed. Chemical additives may be added either before or
after stock preparation. The most common additives are alum
and rosin used for sizing/ which prevents blotting of ink.
Fillers such as clay, calcium carbonate, and titanium
dioxide are added where opacity and brightness of the paper
are important. A wide variety of other additives such as
wet strength resins, dyestuffs, and starches may be used,
depending on end-use requirements.
84
-------
FIGURE 21
DEINKING PLANT PROCESS FLOW DIAGRAM
COOKING
CHEMICALS
MACHINE
WHITE
WATER
PROCESS
WATER
WASTE
PAPER
COOKER
RECYCLE
EXTRACTOR
DEFLAKER
SCREENS
CENTRIFUGAL
CLEANERS
WASHERS
S DECKER
BROWN
STOCK
CHEST
BLEACH
PLANT
BLEACHED
STOCK
CHEST
STEAM
PAPERMAKING
REJECTS
TO
LANDFILL
I
J_
SEWER
LEGEND:
— MAIN PROCESS
— SECONDARY PROCESS
— PROCESS WASTE LINE
85
-------
FIGURE 22
THREE STAGE DEINKED PULP BLEACH PLANT
PROCESS FLOW DIAGRAM
PROCESS
WATER
BROWN
STOCK
CHEST
CHLORINE
TOWER
WASHER
CAUSTIC
TOWER
WASHER
HYPOCHLORITE
TOWER
CENTRIFUGAL
CLEANERS
WASHERS
8 DECKER
BLEACHED
STOCK
CHEST
PAPERMAKING
CHLORINE
CAUSTIC
SODA
HYPOCHLORITE
PREPARATION
-_
—*
SEWER
LEGEND:
— MAIN PROCESS
SECONDARY PROCESS
PROCESS WASTE LINE
86
-------
Either a fourdrinier or cylinder forming machine may be used
to make paper/board. The primary operational difference
between the two types is the flat sheet-forming surface of
the fourdrinier and the cylindrical-shaped mold of the
cylinder machine. The type of machine used has little
bearing on the raw waste load.
In the fourdrinier operation, dilute pulp, about 0.5 percent
consistency, flows from the headbox onto the endless wire
screen where the sheet is formed and through which the water
drains. A suction pick-up roll transfers the sheet from the
wire to two or more presses which enhance density and
smoothness and remove additional water. It then leaves the
"wet end" of the machine at about 35 to 40 percent
consistency and goes through dryers, heated hollow iron or
steel cylinders, in the "dry end."
In the cylinder operation, a revolving wire-mesh cylinder
rotates in a vat of dilute pulp picking up fibers and
depositing them on a moving felt. The pressing and drying
operations are the same as described above. The cylinder
machine has the capacity to make multi-layered sheets which
accounts for its principal use in the manufacture of
paperboard.
Because of its higher speed and greater versatility, the
fourdrinier is in more common use than the cylinder machine.
In either case, coatings may be applied in the dry end or on
separate coating machines. After initial drying on the
paper machine, the sheet may be treated in a size press, and
then further dried on the machine. Calender stacks and
breaker stacks may be employed to provide a smoother finish,
either after drying or while the sheet is still partially
wet.
A flow sheet of the fourdrinier operation is presented in
Figure 23.
87
-------
FIGURE 23
PAPER MANUFACTURING PROCESS FLOW DIAGRAM
PURCHASED
PULP
SLUSH PULP
FROM INTEGRATED
PULP MILL
PROCESS
| , WATER
t
i
NON-INTEGRATED
PAPER MILL
PULP
CHEST
i FILTERED
a WHITF VUATFR ,- - , - -•».
TANK
REFINERS
i t
ALTERNATE
MACHINE
CHEST
FIBER ^AVFAI i
I
r
CENTRIFUGAL
CLEANERS
RICH WHITE
WATER TANK
I L * _
1 ^
MACHINE
SCREENS
COUCH PIT
.....mnifc A MCI
WIRE PIT
I L ^i
1
FOURDRINIER
SECTION
COATER ^~| |
N
PRESS
SECTION
SIZE «•- K-j 1
PRESS -»|n |
!«!
! 1
DRYER
SECTION
DRYER *J U 1
SECTION *^
CALENDER
I
PAPER
PRODUCT
-*j
t
SEWER
LEGEND:
MAIN PROCESS
PROCESS WASTE LINE
88
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SECTION IV
SUBCATEGORIZATION OF THE INDUSTRY
FACTORS OF CONSIDERATION
This section is concerned with sutcategorization of the
industry as it relates to BPCTCA. Subcategories were
established in order to determine effluent limitations and
standards of performance and pretreatment standards for the
groundwood, sulfite, bleached kraft, soda, deink, and non-
integrated paper mills segment of the pulp and paper
industry. In order to identify any relevant, discrete
subcategories, the following factors were considered:
1. Raw materials
2. Production processes
3. Products produced
14. Size and age of mills
5. Waste water characteristics and treatability
6. Geographical location (including climate)
After analyzing these factors, it is concluded that the
segment should be divided into the following 16
subcategories:
1. Bleached Kraft: Dissolving Pulp
2. Bleached Kraft: Market Pulp
3. Bleached Kraft: Fine Papers
4. Bleached Kraft: Paperboard, Coarse, Tissue (B.C.T.) Papers
5. Papergrade Sulfite: Blow Pit Washing
6. Papergrade Sulfite: Drum Washing
7. Dissolving Grade Sulfite Pulp
8. Soda
9. Groundwood: Chemi-mechanical (CMP)
10. Groundwood: Thermo-mechanical (TMP)
11. Groundwood: Fine Papers
12. Groundwood: Coarse, Molded, News (C.M.N.) Papers
13. Deink
11. Non-Integrated (NI) Fine Papers
15. Non-Integrated Tissue Papers
16. Non-Integrated Tissue Papers from Waste Paper (F.W.P.)
Analysis of the above factors resulted in excluding two
types of non-integrated paper mills from the effluent
limitations and standards. These operations included those
non-integrated paper mills producing coarse and specialty
papers. Effluent limitations and standards will be
developed for these types of mills at a later date.
89
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DEFINITIONS OF SUBCATEGORIES
The subcategories are defined as follows:
1. BLEACHED KRAFT; DISSOLVING PULP. This subcategory
includes mills which produce a highly bleached pulp by a
"full cook" process, utilizing a highly alkaline sodium
hydroxide and sodium sulfide cooking liquor. Included in
the manufacturing process is a "pre-cook" operation termed
pre-hydrolysis. The principal product made by this process
is a highly bleached and purified dissolving pulp used
principally for the manufacture of rayon and other products
requiring the virtual absence of lignin and a very high
alpha cellulose content.
2. BLEACHED KRAFT; MARKET PULP. This subcategory
includes mills which produce a bleached pulp by a "full
cook" process utilizing a highly alkaline sodium hydroxide
and sodium sulfide cooking liquor. The product made by this
process is papergrade market pulp.
3. BLEACHED KRAFT; FINE PAPERS. This subcategory
includes the integrated production of bleached kraft pulp
and paper. Integrated production is considered to be pulp
and paper manufacturing operations where all or part of the
manufactured pulp is processed into paper at common or
adjacent sites. The bleached kraft pulp is produced in a
"full cook" process utliizing a highly alkaline sodium
hydroxide and sodium sulfide cooking liquor. The principal
products are fine papers which include business, writing,
printing papers, and market pulp.
H. BLEACHED KRAFT; PAPERBOARD, COARSE, TISSUE
(B.C.T.) PAPERS . This subcategory includes the integrated
production of bleached kraft pulp and paper. Integrated
production is considered to be pulp and paper manufacturing
operations where all or part of the manufactured pulp is
processed into paper at common or adjacent sites. The
bleached kraft pulp is produced in a "full cook" process
utilizing a highly alkaline sodium hydroxide and sodium
sulfide cooking liquor. The principal products include
paperboard (B), coarse papers (C), tissue papers (T) and
market pulp.
5. PAPERGRADE SULFITE; BLOW PIT WASHING. This
subcategory includes integrated production of sulfite pulp
and paper. The sulfite pulp is produced in a "full cook"
process using an acidic cooking liquor of sulfites of
calcium/ magnesium, ammonia, or sodium. Following the
cooking operations, the spent cooking liquor is separated
90
-------
from the pulp in the blow pits. The principal products made
by this process are tissue papers, newspapers, fine papers,
and market pulp.
6. PAPERGRADE SULFITE; DRUM WASHING. This
subcategory includes the integrated production of sulfite
pulp and paper. The sulfite pulp is produced in a "full
cook" process using an acidic cooking liquor of sulfites of
calcium, magnesium, ammonia, or sodium. Following the
cooking operations, the spent cooking liquor is washed from
the pulp on vacuum or pressure drums. Also included are
mills using belt extraction systems for pulp washing. The
principal products made from pulp manufactured by this
process are tissue papers, fine papers, newspapers, and
market pulp.
7. DISSOLVING GRADE SULFITE PULP. This subcategory
includes mills which produce a highly bleached and purified
pulp from softwoods by a "full cook" process using strong
solutions of sulfites of calcium, magnesium, ammonia, or
sodium. The pulps produced by this process are viscose,
nitration, cellophane, or acetate grades and are used
principally for the manufacture of rayon and other products
that require the virtual absence of lignin.
8. SODA. This subcategory includes the integrated
production of bleached soda pulp and paper. The bleached
soda pulp is produced by a "full cook" process utilizing a
highly alkaline sodium hydroxide cooking liquor. The
principal products are fine papers which include printing,
writing, and business papers.
9. GROUNDWOOD; CHEMI-MECHANICAL (CMP). This
subcategory includes the integrated production of chemi-
mechanical groundwood pulp and paper. The chemi-mechanical
groundwood pulp is produced utilizing a chemical cooking
liquor to partially cook the wood followed by mechanical
defibration by refining with or without brightening,
resulting in yields of 90% or greater. The principal
products include fine papers, newsprint, and molded fiber
products.
10. GROUNDWOOD; THERMO-MECHANICAL (TMP). This
subcategory includes the production of thermo-mechanical
groundwood pulp and paper. The thermo-mechanical groundwood
is produced by a brief cook utilizing steam, with or without
the addition of cooking chemicals such as sodium sulfite,
followed by mechanical defibration by refiners which are
frequently under pressure with or without brightening, and
resulting in yields of approximately 95% or greater. The
91
-------
principal products of this process are market pulp, fine
papers, newsprint, and tissue papers.
11. GROUNDWOOD; FINE PAPERS. This subcategory
includes the integrated production of groundwood pulp and
paper. The groundwood pulp is produced, with or without
brightening, utilizing only mechanical defibration by either
stone grinders or refiners. The principal products are fine
papers which include business, writing, and printing papers.
12. GROUNDWOOD; COARSE, MOLDED, NEWS (C.M.N.I PAPERS.
This subcategory includes the integrated production of
groundwood pulp and paper. The groundwood pulp is produced,
with or without brightening, utilizing only mechanical
defibration by either stone grinders or refiners. The
principal products made by this process include coarse
papers (C), molded fiber products (M), and newsprint (N).
13. DEINK. This subcategory includes the integrated
production of deinked pulp and paper. The deinked pulp is
usually brightened or bleached from waste papers in which an
alkaline treatment is utilized to remove contaminants such
as ink and coating pigments. The principal products include
printing, writing, and business papers, tissue papers, and
newsprint.
14. NON-INTEGRATED (N.I.) FINE PAPERS. This
subcategory includes non-integrated (NI) mills which produce
fine papers from wood pulp or deinked pulp prepared at
another site. The principal products of this process are
printing, writing, business, and technical papers.
15. NON-INTEGRATED TISSUE PAPERS. This subcategory
includes non-integrated (NI) mills which produce tissue
papers from wood pulp or deinked pulp prepared at another
site. The principal products of this process include facial
and toilet papers, glassine, paper diapers, and paper
towels.
16. NON-INTEGRATED TISSUE FROM WASTE PAPER (F.W.P.j.
This subcategory includes non-integrated (NI) mills which
produce tissue papers from waste papers (FWP) without
deinking. The principal products made by this process
include facial and toilet papers, glassine, paper diapers,
and paper towels.
92
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RATIONALE FOR SELECTION OF SUBCATEGORIES
The 16 subcategories were determined by extensive
evaluations of the relationships between raw materials,
production processes, products produced, size and age of
mills, waste water characteristics and geographic location
and their effect on raw waste loads, treatability of wastes
and available treatment technologies. These effects and
their contribution to the development of subcategories is
described below. The specific rationale used to determine
each of the 16 subcategories will follow this section.
The basic approach used to technically develop the
subcategories was to first classify the industry by
manufacturing process. The resultant broad classification
was:
A. Chemical Pulping
B. Mechanical Pulping
C. Non-Integrated Paper Mills
D. Deink Paper Mills
The chemical pulping classification was further divided as
follows:
A. Bleached Kraft Pulping and Papermaking
B. Sulfite Pulping and Papermaking
C. Soda Pulping and Papermaking
The division of the pulp and paper industry into the above
specific processes is based upon the premise that raw waste
loads are related to the specific manufacturing process
involved.
These specific process classifications were then thoroughly
evaluated to determine the relationships between the
manufacturing processes and the other factors of
consideration previously described and the resulting process
effluents. This analysis resulted in the development of 16
subcategories for which BPCTCA effluent guidelines would be
determined.
In addition, two groups of mills (coarse paper mills and
specialty paper mills) within the non-integrated paper mills
classification were eliminated from consideration at this
time, because adequate data were not available to support
subcategorization of these groups of mills and develop
effluent limitations.
93
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In evaluating the possibilities for subcategories within the
pulp and paper industry, treatability of wastes was of
primary concern, especially raw waste flow and BOD5 loads.
Many of the technologies identified in this document are for
the reduction of TSS; however, the two primary factors of
external treatment design are flow and BOD5 which were used
as the primary basis for subcategorization.
Table 16 presents the resultant subcategories and the
average raw waste loads associated with each of the
subcategories. These were used to develop effluent
limitations for each subcategory.
RAW MATERIALS
Raw materials were used as a basis for subcategorization.
The primary raw materials used in pulp and paper making can
generally be classified as follows: (1) wood fiber, (2)
chemicals for cooking and bleaching liquors, and (3)
papermaking additives. These three basic raw materials
result in distinctly different raw waste loads depending
upon the specific process used to manufacture a specific
product.
Wood is the primary raw material of nearly all virgin fiber
pulping processes. Consideration was given to
subcategorization on the basis of wood type, but significant
relationships between type of wood and raw waste loads could
not be determined for any of the wood pulping subcategories;
therefore, subcategorization based primarily upon the type
of wood could not be justified.
In production of kraft pulp at a Roe 6 chlorine number, an
unbleached yield of 46% for southern pine has been reported
to be typical (3). With 2% shrinkage in screening and
cleaning, and 9% in bleaching, the softwood yield would be
41%. Sawdust and some species could be somewhat lower,
spruce somewhat higher. A bleached yield of 42% has been
reported to be typical for northern spruce and 43% for
Douglas Fir. Hardwood yield at a Roe 3 chlorine number
would relate to a digester yield of 54% (3). With 1%
shrinkage in screening and cleaning and 7% in bleaching, the
hardwood bleached yield would be 50%. The percentage of
wood not retained as fiber is in either the black liquor,
the screen room effluent, or the bleaching effluent.
Softwood kraft pulp is generally more difficult to bleach to
the same brightness, and greater shrinkage and higher
unbleached lignin content than hardwood kraft result. The
hardwood kraft is also easier to screen and clean and
94
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TABLE 16
SUBCATEGOKY RAW WASTE LOADS
BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY AVAILABLE
Subcategory
FLOW
kl/kkg(kgaI/ton)
BOD 5
kg/kkg(Ibs/ton) mg/L
TSS
kg/kkg (Ibs/ton) mg/L
Dissolving Kraft
Market Kraft
BCT Kraft
Fine Kraft
Soda
GW-Chemi-Mechanica1
GW-Thermo-
Mechanical
GW-CMN Papers
GW-Fine Papers
Papergrade Sulfite
(Blow Pit Wash)
Bisulfite-Surface
Bisulfite-
Barometric
Acid Sulfite-
Surface
Acid Sulfite-
Barometric
Papergrade Sulfite
(Drun Wash)
Bisulfite-Surface 186
Bisulfite-
Baronetric
Acid Sulfite-
Surface
Acid Sulfite-
Barometric
Continuous
Digesters
Dissolving Sulfite
Nitration 275
Viscose 275
Cellophane 275
Acetate 275
Deink 102
NI Fine Papers 63
NI Tissue Papers 96
NI Tissue Papers
(FWP) 105
230
173
148
129
142
113
88
99
91
(55.1)
(41.6)
(35.4)
(30.9)
(34.1)
(27.0)
(21.1)
(23.8)
(21.9)
66.5
38.0
38.4
33.6
43.3
95.5
39.2
17.4
16.7
(133)
(75.9)
(76.7)
(67.2)
(86.5)
(191)
(78.4)
(34.8)
(33.3)
289
219
260
261
304
848
446
175
182
113
45
66.5
75
142.5
52
39.9
48.5
52.5
(226)
( 90)
(133)
(150)
(285)
(104)
(79.8)
( 97)
(105)
491
259
450
582
1002
462
453
489
575
186
221
186
221
221
186
221
227
(44.5) 116 (232)
(53.0) 116 (232)
(44.5) 121 (242)
(53.0) 121 (242)
625
525
652
547
90
90
90
90
(180)
(180)
(180)
(180)
485
407
485
407
(44.5)
(53.0)
(44.5)
(53.0)
(54.5)
(66.0)
(66.0)
(66.0)
(66.0)
(24.4)
(15.2)
(22.9)
134
134
103.5
103.5
139.5
137
156
181.5
202
90
10.8
11.5
(168)
(168)
(207)
(207)
(279)
(274)
(312)
(363)
(404)
(180)
(21.5)
(22.9)
453
380
558
468
614
498
567
659
734
885
170
120
90
90
90
90
90
92.5
92.5
92.5
92.5
202.5
30.8
34.7
(180)
(180)
(180)
(180)
(180)
(185)
(185)
(185)
(185)
(405)
(61.6)
(69.4)
485
407
485
407
396
336
336
336
336
1990
486
363
(25.2)
14.5
(29.0)
138
110.5 (221)
1052
95
-------
produces less rejects. Softwood kraft pulping yields
turpentine and even with removal in a turpentine decanter,
the condensates contain a higher turpentine content than
hardwood.
As the above discussion indicates, it would be expected that
production of kraft pulp with hardwoods would result in
lower raw waste loads. However, examination of wood types
and raw waste loads at the surveyed bleached kraft mills
showed that no significant relationships were apparent. As
an example of the examinations of the total raw waste load
in relation to the type and characteristics of the wood for
the pulping subcategories. Table 17 is presented showing the
raw waste flow and BOD5_ values in relationship to the type
of wood for the bleached kraft subcategories. In addition,
Figures 24 and 25 present raw waste flow and BOD5 values,
respectively, relative to the percent hardwood and softwood
used at each mill. An analysis of Figures 24 and 25 do not
show a definite relationship relating the specific effects
of wood type on raw waste loads. It appears that the raw
waste load is more impacted by other more significant
factors than the type of wood.
Because of the multitude of interplaying factors on raw
waste load, efforts were made to attempt to subtract out
several items and isolate the impacts of hardwood and
softwood. These items included: woodyard operations,
continuous or batch digesters, and five versus six stages of
bleaching. Adjustment of mill raw waste loads used the
following for the above items: 3.0 kg/kkg (6.0 Ibs/ton), 2.5
kg/kkg (5.0 Ibs/ton), and 41.7 kl/kkg (10.0 kgal/ton) ,
respectively; however, these assumed adjustment factors were
based upon theory, and data were unavailable from mill
survey information and data to confirm them. The analysis
is discussed below.
A total of 6 market pulp mills, 12 BCT paper mills, and 14
fine paper mills are tabulated in Table 18. Mills1 130,
187, 122, 149, 161, 101, 116 and 134 were not used for the
analysis primarily because of insufficient or inappropriate
data. This left 24 mills for the analysis. Half of the
mills have the more recent survey data to use for analysis
and half have older data. To compare the change on raw
effluent data during the two years separating the surveys,
10 mills were determined to have both 1973 and 1975 data
available. The effect of the two years represented by the
more recent data is an average reduction in raw waste flow
of 4% and BOD5_ of 13%. Thus an adjustment was made for the
other mills with 1973 data amounting to 5.4 kl/kkg (1.3
kgal/ton) flow and 5 kg/kkg (10 Ib/ton BOD5_) . In addition,
96
-------
TABLE 17
Mill Code
Market Pulp
126
140
114
139
186
BCT Papers
105
109
111
121
100
113
117
131
122
Fine Papers
112
118
119
132
101
103
106
107
110
120
135
136
Dissolving Pi-
127
108
510
Wood Type
% Softwood
55
0
69
45
95
67
78
43
70
45
50
100
80
80
0
33
37
78
50
52
83
50
33
0
16
67
100
84
20
BLEACHED KRAFT MILLS
WOOD TYPE VS RAW WASTE LOAD
Flow
k1/kkg(kga1/ton)
180.0 (43.1)
78.8 (18.9)
176.0 (42.3)
85.1 (20.4)
188.0 (45.0)
162.
167.
138.
158.
152.
139.
205.
159.
(38.9)
(40.0)
(33.
(37.
(36.
(33.
(49.
(38.
.1)
.9)
.5)
.3)
•2)
1)
123.0 (29.5)
126.0
125.0
89.0
81.0
152.0
168.0
160.0
118.0
106.0
132.0
169.0
120.0
(30.1)
(30.0)
(21.3)
(23.8)
(36.4)
(40.2)
(38.4)
(28.3)
(25.3)
(31.7)
(40.6)
(28.7)
252.0 (60.5)
306.0 (73.3)
131.0 (31.5)
^
kg/kkg(1bs/ton)
28.0 (56.0)
(55.4)
(93.0)
(82.4)
37.5 (75.0)
27.
46.
40.
29.
20.
21.
36.
26,
37.
34,
44,
31.
49,
37.
36.4 (72.7)
35.6 (71.2)
(58.9)
(59.8)
(89.0)
29.5
29.9
45.2
37.0 (74.0)
29.9 (59.8)
45.2 (90.3)
29.0
(58.7)
(40.6)
(42.4)
(72.5)
(52.2)
(74.9)
(59.0)
(88.3)
(62.1)
(99.3)
(74.4)
(58.0)
37.3 (74.0)
85.5 (171.0)
76.0 (152.0)
97
-------
Figure 24
Raw Waste Flow vs. Type of Wood
(Softwood-Hardwood)
325^
BLEACHED KRAFT MILLS
300
2504'
200] •
150.
100
50.
*• % Softwood i
90 80 70 60 50 40 30 20 10 0 .
~~l 1 i i I I i i I " I
10 20 30 40 50 60 70 80 90 100
% Hardwood-*
-------
Figure 25
Raw Waste BCDs vs. Type of Wood
(Softwood - Hardwood)
Bleached Kraft Mills
LOO
90
80
70
I
10
20
I
30
60
40
<-% Softwood
50
T~
50
% Hardwood-*
40
60
30
'"T
70
20
~ T
80
10
90
100
-------
TABLE 1R
BLEACH KRAFT EFFLUENT CHARACTERISTICS *
Mill
No.
Effl.
Data
i
Mkt.
'rodi
EC:
Market Pulp
114
126
130
139
140
187
BCT
100
105
109
111
113
117
121
122
131
138
149
161
Fine
101
103
106
107
110
112
116
118
119
120
132
134
135
136
1975
1975
1975
1975
1975
1975
Papers
1973
1973
1973
1975
1975
1975
1973
1973
1975
1975
1975
—
Papers
1973
1973
1975
1973
1973
1973
1975
1973
1975
1973
1973
1973
1973
1973
100
100
100
100
100
100
20
—
—
—
29
33
10
30
20
15
—
16
45
50
57
25
30
—
—
—
—
35
—
—
40
5
—
—
—
—
—
80
100
100
100
71
67
90
70
80
85
100
84
—
—
—
—
—
—
—
—
—
—
—
—
40
Fine
Furnish 7-
Purch. Other
45
50
43
75
70
100
100
100
100
65
100
100
60
55
10
25
27
50
20
12
10 GW
20 WP
S.W.
45
57
78
53
50
100
70
80
100
37
52
83
100
33
0
0
33
34
0
0
30
63
Wet
Wdrm.
Hatch Bleach Raw Effl.Load/Ton
Dig. Stg. Flow BOn TSS
(kgal) (Ib) (Ib)
X
X
X
X
X
X
807
1/2
X
X
X
X
X
1/7
X
X
X
X
6
5
5
5
5
5
4/6
4/6
4
4 1/2
4 1/2
4
5
•IA
4
4
4
4
4
5
5
41.5
40.0
74.9
27.6
20.1
31.4
41.2
38.1
40.0
32.3
2«.0
45.2
37. 9
29.5
38.1
32.5
13.3
37.2
A3. 4
37.3
27.0
24.0
26.4
35.4
25.7
1^.2
31.2
19.5
22.3
40.3
28.7
92.8
54.7
104
79.8
55.9
135
8°.0
72.7
71.2
54.5
52.6
67.0
5". 8
90.3
121
98.0
28.5
57.6
74.9
69.0
81.6
55.4
49. It
88.6
40.6
38.1
96.0
47.0
61.7
74.4
58.0
31.3
45.0
145
—
—
— ~
63.7
—
255
107.9
103. 3
—
—
104
—
80
64.1
121
139
97.8
—
116
—
—
—
80.3
124
256
165
146
1.57
*Data shown is for theoretical analyses only (see text).
100
-------
an adjustment was made for 6 stage bleaching, wet woodrooms
and batch digesters. To determine the passible effects of
softwood versus hardwood on kraft raw waste, the mills were
split into increments of 20% softwood and the average
adjusted flow and BOD5_ were determined.
The data included in the analyses is based on 24 of the 32
mills listed in Table 18 with insufficient or inappropriate
data, accounting for dropping 8 mills from the comparison.
The results of the analyses are presented in Figures 26 for
flow and 27 for BOD^. As shown, there appears to be a
tendency for mills using hardwoods to have lower raw waste
loads which confirms the previous theoretical discussion.
However, it must be emphasized that the above analyses were
limited by a number of constraints and that the analyses
were also theoretical; the analyses were unable to use as
much mill data as felt to be necessary to determine reliable
results because of either insufficient data or data that did
not fit the assumptions of the analyses and therefore could
not be properly included in the analyses; and the analyses
were limited to adjustment for only several items due to the
availability of data and thus did not examine several other
items which could overshadow the results, including the
extent of in-plant controls at each mill and the
effectiveness of the black liquor recovery (the recovery
factor which is discussed later in this section). Because
of the above limiting constraints, the conclusion that can
be drawn from the analyses is that in theory there is a
tendency for hardwoods to result in lower raw waste loads
than softwoods; however, as shown in Figures 2U and 25, the
actual manufacturing operations at the surveyed mills which
use varying amounts of hardwood or softwood do not correlate
with raw waste load because of the multitude of interplaying
factors which are present at every mill. It is not
realistic to simulate a theoretical "model" type facility
upon which to base subcategorization and effluent
limitations.
Subcategorization into mills producing bleached fine papers
and bleached kraft BCT papers appears to somewhat correlate
with the use of hardwoods or softwoods and any tendency
(real or theoretical) towards lower raw waste loads for
mills using hardwoods is taken into account in the
subcategorization as discussed below. Of the mills
compared, the following breakdown of products indicates the
possibility of other factors influencing the results. The
following data are offered to show that the end product
factors may also influence the curves in Figures 26 and 27.
It can be seen on Table 19 that 7 of the 10 bleached kraft
fine mills fall in the 60-100% hardwood group and all 9 of
101
-------
Adjusted
Flow
Kgal/ton I
40 j
FIGURE 26
RAW WASTE FLOW VS. TYPE OF WOOD *
BLEACHED KRAFT
o
ro
30
20
-t-
-I-
100
0
80
20
60
40
40
60
20
80
0 % Soft Wood
100 % Hard Wood
*Theoretical Analysis (See Text)
-------
FIGURE 27
RAW WASTE BODS^ VS. TYPE OF WOOD *
BLEACHED KRAFT
Adjusted
BODS^
lb/ton
60
50
o
to
40
30
-f-
100
0
80
20
60
40
40
60
20
80
0 % Soft Wood
100 % Hard Wood
^Theoretical Analysis (See Text)
-------
the bleached kraft BCT mills fall in the 40-100% softwood
group. This tends to agree with the average raw waste loads
in Table 16.
TABLE 19
BLEACHED KRAFT
HARDWOOD/SOFTWOOD VS. PRODUCT
% Softwood
0-20
20-40
40-60
60-80
80-100
% Hardwood
80-100
60-80
40-60
20-40
0-20
Total Mills
Averaged
4
5
6
5
3
Subcategory
Market BCT Fine
1
1
1
1
4
3
2
3
4
1
1
1
The limitations are therefore based on a cross section of
mills surveyed in the subcategories as established by
product and process factors without allowance for wood
species other than the inherent product related factors
present in the subcategory rationale.
As shown in Table 20 sulfite mills do not show an
appreciable effect of wood species on effluent load. The
sulfite processes are adapted to handle different wood
species and thus the effect of wood species on raw waste
load is largely overshadowed by process differences which
are described later in this section. Limits for dissolving
sulfite mills have been set for softwoods only because there
is only one known mill using any appreciable amount of
hardwoods and recent data received from that mill's
management have indicated that there may be some impact on
raw waste loads. However, there was insufficient data to
develop limitations.
In addition to the type of wood, consideration was given to
the condition of the wood (i.e. chips or logs) as it arrived
at the mill. This difference in raw materials relates to
the process factor because depending upon the form of the
wood, additional waste loads are generated by some mills
using wet log debarking processes. Mills receiving wood as
chips do not have this source of waste. In addition, the
season of the year in which the wood is harvested may have
some impact on waste loads in that the amount of water
extractable material underneath the bark and the difficulty
in bark removal may vary by the season. These variations.
104
-------
TABLE 20
SULFITE SUBCATBGORIES
AGE/WDCD TYPE VS RAW WASTE LOAD
Mill
Age
Years
Type Wood
% Softwood
Flow
kl/tag (legal/ton)
BODS
kg/kkg(lbs/ton)
Dissolving Sulfite
511
512
050
401
402
403
23
16
36
18
46
45
100
100
100
84
100
97
269 (64.4)
246
274
275
274
256
(58.9)
(65.8)
(66.0)
(65.8)
(63.8)
143 (286)
150
-
156
209
195
(299)
( - )
(311)
(417)
(390)
Papergrade Sulfite
060
006
007
052
051
053
068
056
062
066
065
063
071
059
70
49
67
85
54
6
43
122
76
75
-
77
54
69
75
100
100
100
100
0
100
5
100
0
0
30
70
100
227
117
176
170
251
86.7
254
231
174
186
197
199
208
173
(54.5)
(28.0)
(42.1)
(40.8)
(60.2)
(20.8)
(61.0)
(55.3)
(41.7)
(44.7)
(47.2)
(47.8)
(49.9)
(41.4)
140
61.5
44.9
79.0
114
95.5
112
116
74.5
-
77.5
89.0
121
110
(279)
(123)
(89.7)
(158)
(227)
(191)
(223)
(232)
(149)
( - )
(155)
(178)
(242)
(220)
105
-------
however, are relatively insignificant when compared to the
total waste load and flow generated in the woodyard
operations. In addition to debarking operations, additional
waste load is generated at some mills in (1) the use of
flumes for log transport and partial thawing of logs, (2)
log washing operations, and (3) the use of hot ponds for
thawing logs. These are not large sources of waste loads
but nevertheless their use constitutes an additional waste
load not present at mills using wood chips as their raw
material. There are a large number of mills which have dry
woodyards which means that mechanical conveyors are used to
transport the logs to dry drum debarkers. For mills located
in northern climates, the additional operations of thawing
logs, the bark, or the material frozen to the bark is
sometimes done in either hot ponds or hot transport flumes
prior to debarking. The use of steam prior to drum barkers
is an alternate technology to hot ponds or flumes which is
used by a number of mills. This process, however, does not
thaw the log, it only removes the material (dirt and rocks)
that is frozen to the surface of the logs. Consideration
was given to developing subcategories based upon chips vs.
logs because these operations result in an effluent waste
load not present from mills using only chips. However, the
wet woodyard operations are similar for all mills and thus
are not unique to any one type of mill. Instead of
subcategorization, additional allowances are included in the
BPCTCA effluent limitations for mills practicing wet
woodyard operations without regard to the subcategory (See
Section V and IX). It should be pointed out that provision
of an additional allowance for mills using woodyard
operations involving hot ponds or hot flumes for defreezing
logs is also taking the geographical location factor into
account since only mills located in Northern climates use
these operations.
The use of whole tree chips (WTC) was discussed briefly in
Section III as a possible change in raw materials which some
mills may use in the future as a substitute or as a
supplement for their present wood supply. While WTC may
provide additional fiber, laboratory studies have shown that
the use of WTC will result in (1) significant modifications
to the existing production process and the associated
equipment and (2) higher raw waste loads (307). However,
WTC is presently used by only a few mills for small part of
their total fiber supply and primarily upon an experimental
basis. Therefore, the use of WTC as a basis for
subcategorization is not appropriate at this time.
The source of wood fiber used as the raw material was used
as a basis for subcategorization. The sources of fiber are
106
-------
(1) wood (as described above), (2) pulp, and (3) waste
paper. Again, subcategorization by these fiber sources was
closely related with the process. Non-integrated paper
mills do not have wood pulping facilities and thereby depend
upon either pulp or waste paper as their fiber source.
Distinctly different BOD5_ loads result from the use of pulp
or waste paper as the fiber source. This is apparent in
Table 16 which shows the NI tissue papers subcategory BOD5_
raw waste load of 11.5 kg/kkg (22.9 Ibs/ton) which by
definition uses purchased pulp as the fiber source. By
comparison, the Deink subcategory raw waste BOD5_ is 90.0
kg/kkg (180 Ibs/ton). This subcategory uses waste paper as
a fiber source. Both of these subcategories produce the
same product but were subcategorized on the basis of raw
materials.
The chemicals used in preparation of the cooking liquors and
in the bleaching process can have significant effects upon
raw waste load, but again this is primarily a function of
the process and product factors. The subcategorization of
the industry used chemical cooking liquors as a basis and is
shown by the two distinct types of chemical pulping: kraft
and sulfite. Bleached kraft mills use a highly alkaline
cooking liquor resulting in BOD5 raw waste loads ranging
from 20 to 60 kg/kkg (40 to 120 Ibs/ton) depending upon
final product qualities. Sulfite mills, on the other hand,
use acidic cooking liquors resulting in BOD5 raw waste loads
ranging from 75 to 200 kg/kkg (150 to HQO Ibs/ton). The
difference between kraft and sulfite relate to the recovery
of the spent cooking chemicals and to the reuse of the
condensates. In addition, investigations have shown that
the BOD5_ of kraft black liquor is approximately 0.15 kg/kg
(0.15 Ib/lb) of solids, whereas comparable values for
sulfite spent liquor are approximately 0.23 to 0.30 kg/kg
(0.23 to 0.30 Ib/lb) of solids (307). The difference in
cooking liquors results in substantially higher raw waste
loads for sulfite mills with the same degree of liquor
recovery as kraft mills. Therefore, the maximum efficiency
in recovering spent cooking liquors, especially for sulfite
mills, is a necessity in minimizing raw waste loads.
Papermaking additives were used as a basis for
subcategorization primarily as they related to the final
products. The additives have a discernible effect upon raw
waste loads with the most significant effects shown by the
non-integrated paper mills. These mills do not engage in
wood pulping, but the wastes reflect the use of a wide
variety of fiber types, fillers, wet strength agents,
starches, resins, and other additives. While it would be
expected that the use of papermaking additives such as
107
-------
starches which contribute to the BOD5 raw waste load would
result in higher raw waste loads for mills producing fine
papers, it appears that the use of filler materials (i.e.
clays) which are also used by mills using starches outweighs
the impact of the added BOD5_ load due to starches. The
filler materials in fine papers are included in the off-the-
machine production figures used to calculate the kg BOD5/kkg
(Ib. BOD5/ton) of production. In addition, the use of some
papermaking additives such as retention aids tend to reduce
raw waste loads.
Mills producing papers with little or no filler content such
as tissue papers do not have this additive in their
production figures. These relationships are apparent in the
raw waste loads which were determined for the NI fine papers
and NI tissue papers subcategories. The BOD5 raw waste
loads were 10.75 kg/kkg (21.5 Ibs/ton) and 11.5 kg/kkg (22.9
Ibs/ton), respectively. The TSS raw waste loads were 30.8
kg/kkg (61.6 Ibs/ton) for NI fine and 34.7 kg/kkg (69.U
Ibs/ton) for NI tissue. The use of papermaking additives
was also used as a basis for subcategorization of groundwood
mills producing fine papers and CMN papers (papers with low
filler content) and bleached kraft mills producing fine
papers and BCT papers (papers with low filler content) . Of
course, the subcategorization of the groundwood and bleached
kraft subcategories was not entirely based upon raw
materials because process and product factors also had
significant impacts on raw waste loads.
The deink subcategory can be used as an example of how the
three basic classifications of raw materials (fiber,
chemicals, additives) were used in the development of the
subcategories. Deink mills are similar to non-integrated
paper mills in that deink mills have no chemical or
mechanical wood pulping on site, although chemicals are
added to disperse papermaking additives in the waste paper
furnish. In addition, both deink and non-integrated paper
mills purchase their fiber and manufacture similar products
by similar process. The most significant differences are in
the raw materials and in the manufacturing process which
must be used to produce the final product qualities.
Because waste paper is the fiber source rather than the
relatively much cleaner purchased pulp used by non-
integrated paper mills, chemicals must be used in the deink
manufacturing process to clean the waste paper to the
specifications demanded by product qualities. Similar
products are manufactured by deink mills and non-integrated
paper mills using various papermaking additives, but this
has lesser effects upon the raw waste load than the above
two factors. Deink mills were subcategorized separately
108
-------
from the non-integrated mills primarily because of the raw
materials used which in turn have a direct impact in
determining the manufacturing process. Because of the raw
materials, the primary purpose in the repulping of the waste
paper is to remove the non-fibrous materials, such as
pigments, starches, and inks (papermaking additives), and it
is actually a cleaning and bleaching process. On the other
hand, the primary purpose of non-integrated paper mills in
repulping purchased pulp is merely to separate the fibers
previous to forming the sheet of paper. These differences
have significant effects upon the raw waste load as can be
seen in Table 16 which shows the effluent flow to be similar
for deink mills and non-integrated paper mills but the BOD£
and TSS are significantly higher for deink mills.
PRODUCTION PROCESSES
Production processes were used as the primary basis for
subcategorization since . differences in waste water
characteristics and treatability are most significantly
affected by the manufacturing process. Of course, the
manufacturing process is closely related to raw materials
and final products, and these two factors are inherently
included in any evaluations involving the manufacturing
process.
All chemical pulping processes are similar in that each uses
digestion of wood chips with a chemical cooking liquor and
the removal of spent liquor from the cellulose pulp.
Process differences among the various pulp types which have
significant impacts on raw waste load relate primarily to
the preparation, use, and recovery of cooking liquor. Such
liquors are generally not used to make groundwood pulps,
although small quantities are applied in some grades. The
deinking process does not employ cooking liquors, although
chemical treatment is used in the separation of cellulose
fibers in waste papers. Non-integrated mills employ no
cooking chemicals.
It should be pointed out that recovery of the spent cooking
liquor appears to be the one most significant factor (the
"recovery factor") affecting raw waste loads at bleached
kraft, soda, and sulfite mills. The degree of efficiency of
cooking liquor recovery has a significant effect upon the
total mill raw waste load at the three types of mills. The
degree of spent liquor recovery is a function of the
efficiency of the pulp brownstock washing operations,
because the spent liquor which is not removed from pulp and
sent to the evaporators is carried with the pulp to the
screening and bleaching operations. In the screening and
109
-------
bleaching operations, the remaining spent liquor not removed
in washing is lost to the screen room or bleach plant
sewers, depending on the degree to which the screen room, is
"closed". Since the BOD5 of sulfite spent liquor is 50 to
100% higher than the BODj> of kraft black liquor, the degree
of spent liquor recovery is relatively more critical in
sulfite mills than in bleached kraft or soda mills in order
to minimize the raw waste load from the initial design
capacities of the spent liquor recovery system including
brownstock washers, evaporators, boilers, and chemical
recovery operations. Operating at beyond the design ratings
of each of the above operations would result in higher raw
waste loads due to inefficient liquor recovery. The
increasing demand for paper products over the years has put
increasing pressures upon mills to produce more pulp and
paper per day with existing facilities. Mills generally
will continue to increase production by eliminating the
minor bottlenecks and pushing the facilities beyond their
design rated capacities until an economic breakpoint is
reached, at which point major expansion of the existing
facilities becomes more economical. Production above design
capacity sometimes relates to inefficient spent liquor
recovery causing a loss of valuable cooking chemicals in
addition to higher waste water treatment costs due to the
higher raw waste loads. Consideration was given to
subcategorization based upon the degree of liquor recovery
within the bleached kraft, sulfite and soda subcategories,
but it was determined to be more appropriate to
subcategorize on the overall process and product factors,
rather than possibly inhibiting the potential production
expansions of mills within the subcategories. The BPCTCA
effluent limitations for the papergrade sulfite
subcategories were, however, differentiated for mills
practicing blow pit washing and drum washing which result in
different degrees of spent sulfite liquor recovery. For
these mills, the type of washing is actually a function of
the age of the mill. A discussion on subcategorization
based on blow pit versus drum washing in sulfite mills is
presented later in this section in the Sulfite Subcategory
Rationale.
As discussed previously, consideration was given to basing
subcategories on the use of logs or chips because additional
production processes are required for mills using logs. For
some mills using logs, additional sources of waste water are
generated depending primarily upon if the woodyard
operations use water for either thawing logs or bark,
transporting logs, washing logs, or debarking logs. The use
of these operations is frequently a function of the
geographical location of the mills. Mills in the Pacific
110
-------
Northwest frequently use wet debarking operations because
other methods of debarking are unacceptable due to the large
size of the logs (unique to the Pacific Northwest and
Alaska) used as raw materials. Mills located in Northern
climates, such as Minnesota or Maine, sometimes require
thawing operations during winter months to enhance the
debarking operation. Mills using these operations have an
additional source of waste over those mills not using
similar operations. Since the woodyard operations are
similar for bleached kraft mills, sulfite mills, soda mills,
and groundwood mills, additional allowances were provided in
the BPCTCA effluent limitations for mills using three types
of woodyard operations: (1) wet debarking, (2) log flumes
and hot ponds, and (3) log and chip washing/thawing
operations.
Virtually all of the industry use similar papermaking or
forming equipment to manufacture paper or pulp products, as
described in Sections III and V. Process differences in the
papermaking process relate primarily to the additives used
to produce specific product qualities (i.e. book paper vs.
paperboard) , and several subcategories were determined on
the basis of additives used in papermaking.
There are a number of operations within the papermaking
process that have the potential of some impact upon raw
waste load. Some of these include the following:
papermaking additives used, number of paper grades produced,
frequency of grade changes, form of the final out-the-door
product (i.e. sheets vs. rolls), and certainly the degree of
internal waste water control and reuse. Consideration was
given to subcategorization based upon the above operations,
and the primary impact on raw waste load was determined to
be the papermaking additives. As discussed previously,
several subcategories were determined on the basis of
additives. Because the number of grades and frequency of
grade changes at a mill varies as mills respond to market
conditions (i.e. mills may produce a large number of grades
with frequent changes for a few months and then market
conditions could change requiring only one or a few grades
with infrequent grade changes for the same mill), further
subcategorization was determined to be inappropriate.
Instead a large number of mills with available data which
had varying papermaking characteristics including numerous
and frequent grade changes, different final product forms,
and varying amounts of inplant control measures, were
included in the data base (upon which the effluent
limitations were based).
Ill
-------
The effects of the process differences on waste
characteristics can be seen in Table 16. It should be noted
that treatability of waste water is accounted for in the
subcategorization process by subcategorizating on the basis
of similar processes and raw materials which contribute
similar types of waste waters.
PRODUCTS PRODUCED
The wide variety of products produced by this segment of the
industry is discussed in Section III. Differences in waste
water characteristics generated are substantial but actually
these differences are more attributed to the process and raw
materials rather than products produced. For example,
tissue papers are manufactured by both bleached kraft and
sulfite mills yet the waste water characteristics of the
effluents generated by the manufacturing processes are
significantly different.
As shown previously, bleached kraft was divided into four
subcategories: (1) dissolving pulp, (2) market pulp, (3)
paperboard, coarse, and tissue papers, and (4) fine papers.
Within bleached kraft, the variations of the process used to
produce the above products is the most significant factor in
characterizing the waste waters rather than the products
themselves. Another example is the subcategorization of the
non-Integrated paper mills into NI fine papers and NI tissue
papers. The primary differences in waste water
characteristics from these mills relates to the additives
used in the papermaking process rather than to the products.
Of course, the qualities of the final product determine the
specific process, the process operating conditions, and the
papermaking additives which are used.
Newsprint manufacture can also be used as a further example
of different processes producing similar products.
Consideration was given to subcategorization on the basis of
newsprint manufacture as newsprint uses two specific types
of pulp: 65-80% groundwood and 20-35% chemical pulp.
Approximately 13 integrated mills manufacture newsprint;
however, these integrated mills are similar only in that
each produces groundwood pulp on-site and newsprint is the
final product (or one of many products). Table 16 shows
process information for 12 of the integrated mills producing
newsprint. The dissimilarities between the mills relates
primarily to process and products as several mills produce
100% newsprint using groundwood pulp along with either
bleached kraft, unbleached kraft, or sulfite pulps produced
on-site. In addition, nine of the 13 mills produce other
products besides newsprint. These differences in the
112
-------
process (as well as raw materials such as cooking liquors)
result in significant differences in the raw waste loads at
each of the mills. Mills that produce newsprint from on-
site groundwood pulping and purchased chemical pulp are not
included in the table. Thus, the products themselves were
considered and were used as a basis for subcategorization
but only as they related to the process and raw materials.
The dissolving sulfite subcategory was established on the
basis of products produced. Although the cooking liquor and
the process is similar to that of papergrade sulfite, the
raw wastes are significantly higher as is shown in Table 16.
Process differences were examined as a basis for
subcategorization such as bleaching sequence or % GE
brightness. It was found that various bleaching processes
could be used to produce a given grade pulp with a low
lignin content or alpha cellulose content. It was also
found that the % GE brightness was not a good indicator of
the lignin content of the pulp.
Since the uses of the dissolving pulp dictate the pulp
qualities required, a subcategory was established based on
products produced. One subcategory was determined for all
sulfite dissolving pulps and allowances were provided for
the four basic grades of sulfite dissolving pulps commonly
produced by the sulfite process. These are (1) nitration
grade, (2) viscose grade, (3) cellophane grade, and (U)
acetate grade. These four classifications are based on
products produced although it is obvious that the product
specifications determine the process requirements, which are
described later in this section. The pulp properties,
mainly the cellulose content and the viscosity of each of
these grades is varied to provide the properties which are
desirable for its particular end use.
AGE AND SIZE OF MILLS
There is a substantial difference in age as well as size
among mills in the industry. Mills built over 100 years ago
are still in operation along with the new ones built within
the last few years. Most of the older mills have been
substantially upgraded, modernized, and expanded, so that
they are not "old" in the production sense. Because of
this, differences in waste water characteristics related to
age of mill are not discernible in the data from surveyed
mills, thus substantiating the sufccategories defined by
other factors. The following examples from the bleached
kraft subcategories illustrate this point. Mill 111, built
in 1912 and modernized as recently as 1973, produced 667
113
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kkg/day (735 tons/day) with a raw waste BODji load of 29.5
kg/kkg (58.9 Ib/ton). Mill 112, built in 1969, produces
about the same tonnage, i.e. 580 kkg/day (610 tons/day),
with a nearly identical BOD5 load of 29.35 kg/kkg (58.7
Ib/ton). Mill 118 is much smaller, producing 174 kkg/day
(192 tons/day) and was built in 1867, rebuilt in 1951, and
modernized in 1964, and has a BOD5 raw waste load of 20.3
kg/kkg («0.6 Ib/ton). Table 21 compares the age of the
original facility for bleached kraft mills with the mills'
raw waste loads.
The use of the age of the original facility (the cornerstone
age) in evaluation of the impact of the age factor upon raw
waste loads is regarded as the only adequate method of
considering the age factor for this industry. Old mills
have generally continually upgraded and modernized their
production facilities in order to remain competitive with
newer mills using the latest technologies. Typical case
history of old mills upgrading, rebuilding, modernizing, and
expanding their facilities are shown below:
Mill
119
Year
186U
1930-1965
195U
1963-1966
Year
1912
1950
1950
196U
1966
1973
Year
1937
1955
1963
1968
1968
1968
1968
Activity
Built original facility
Added or rebuilt paper
machines No. 1,2,7,8
Converted from soda to kraft
Pulp mill expansion
Activity
Built original facility
Added bleach plant
Added number 5 paper
machine (P.M.)
Rebuilt number 5 P.M.
Number 3 recovery built
Rebuilt number 5 P.M.
Activity
Built original facility
New board machine added
New tissue machine added
New woodyard
Expanded pulp mill
New recovery
New tissue machine
114
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TABLE 21
BLEACHED KRAFT SEGMENT
AGE vs RAW WASTE LOAD
Mill Code
Market Pulp
126
140
114
139
186
BCT Papers
109
111
121
100
113
117
131
122
Fine Papers
134
112
118
119
132
101
103
106
107
110
120
135
Dissolving Pulp
127
108
Year Built*
1966
1969
1967
1968
1965
1041
1912
1954
1958
1951
1969
1928
1970
1888
1169
1867
1864
1890
1971
1964
1968
1964
1972
1937
1970
1954
1«»54
Flow
kl/kkg(kgal/ton)
180
78,8
176
85.1
188
167
138
158
152
139
205
159
123
252
306
(43.1)
(18.9)
(42.3)
(20.4)
(45.0)
(40.0)
(33.1)
(37.9)
(36.5)
(33.3)
(41.2)
(38.1)
(29.5)
100
126
125
89
81
152
168
160
118
106
132
169
(24.1)
(30.1)
(30.0)
(21.3)
(23.R)
(36.4)
(40.2)
(38.4)
(28.3)
(25.3)
(31.7)
(40.6)
(60.5)
(73.3)
BOD5,
kg/kkg(lbs/ton)
28.0
27.7
46.5
40.7
37.5
35.
29,
29.9
45.2
37.0
29.9
45.2
37.3
85.5
(56.0)
(55.4)
(93.0)
(82.4)
(75.0)
(71.2)
(58.9)
(59.8)
(89.0)
(74.0)
(59.8)
( - )
(Q0.3)
35.9
29.3
20.3
21.2
36.3
26.1
37.5
34.5
44.2
31.1
49.7
37.2
(71.8)
(58.7)
(40.6)
(42.41
(72.5)
(52.2)
(74.9)
(69.0)
(88.3)
(62.1)
(99.3)
(74.4)
(74.0)
(171)
* This data reflects the year the original facility was built and does not
show the major upgrades or expansion of the facilities.
115
-------
Although the above historical data concerning mill upgrades
and expansions is quite limited, the information on the
three mills does illustrate the fact that old mills have
upgraded their facilities so that they can remain
competitive with the newer mills. The cornerstone age of a
mill generally indicates the extent of physical restraints
at a facility which can have an impact on the difficulty of
installing new inplant controls in an old facility. Because
of this, the cornerstone age was examined in relation to raw
waste loads in order to determine the success of mills in
implementing internal controls and process upgrades and
modifications. As shown in Table 21, there is no apparent
correlation existing between age and raw waste loads for
bleached kraft mills. In addition. Table 20 presents age
and raw waste load data for sulfite mills and again no
correlation is apparent.
Consideration was given to subcategorization based upon the
age of the process equipment from which the raw waste load
is generated. However, the efforts showed that the only
feasible way in most cases of examining raw waste loads in
relationship to the age of the process equipment was to only
evaluate the newest mills which had not upgraded or
modernized any of the process equipment. There are numerous
sources of raw waste load in the pulp and papermaking
process and a multitude of associated process equipment.
Older mills, such as the three mills listed above, have
continually upgraded and modernized their process equipment
in order to remain competitive and in some cases in order to
meet the requirements of environmental regulatory agencies.
The constant upgrading or replacement of process equipment
or even replacement of parts of a piece of process equipment
certainly does not lend itself to determination of a
specific age for each piece of equipment and evaluation of
raw waste loads associated with those equipment ages.
The exception to the above discussion of the difficulties in
determination of the age factor based upon process equipment
is in the papergrade sulfite subcategories. As discussed
previously, the most significant factor affecting raw waste
load for the chemical pulping subcategories is the degree of
spent liquor recovery. The type of equipment used in pulp
washing is critical to recovering the maximum amount of
spent liquor. Because of the necessity in the bleached
kraft and soda subcategories to recover the cooking
chemicals, mills have upgraded and replaced their previous
pulp washing systems and have installed the more efficient
countercurrent brownstock pulp washing systems. For
recovery of the spent sulfite liquor (SSL), sulfite mills
employ either blow pit washing or counter-current vacuum
116
-------
drum washing (or in some cases pressure drum washing or
vacuum belt extraction) which is similar to bleached kraft
and soda mills. All sulfite mills have not upgraded their
pulp washing equipment primarily because the economic
incentive for recovering as much of the spent liquor as
possible does not always apply to sulfite. Therefore, some
sulfite mills are still using the older blow pit washing
systems which are not as efficient as the newer vacuum drum
washing systems (29). This has resulted in separate
subcategories for blow pit washing and drum pulp washers.
In addition the type of cooking liquor, (i.e. acid sulfite
or bisulfite) and the type of evaporator condensers, (i.e.
barometric or surface) were found to have a significant
effect on raw effluent load and flow. These differences
have been accounted for by providing additional allowances
to the effluent limitations for the acid sulfite process and
for barometric condensers in the papergrade sulfite
subcategories. All of these factors are indirectly related
to the age of the mill. The older sulfite mills have mostly
blow pit washing, acid sulfite cooking acid, and barometric
condensers (if they have evaporators). Many newer or
recently improved mills have drum type pulp washers,
bisulfite cooking acid, and evaporators with surface
condensers.
Another example of older equipment resulting in higher
effluent flows is in kraft bleach plants. Newer mills with
all 317 stainless steel bleach washers can take advantage of
extensive recycle of bleach filtrates to reduce effluent
flow. Older bleach plants with 316 stainless steel washers
or poorer encounter extensive corrosion with some filtrate
recycle and thus have to use more fresh water and have
increased effluent flow. This factor is not as large as the
factors for sulfite mills shown above. Thus an allowance
for the older equipment was not made, but in effect the
bleached kraft limitations are based on the older equipment
since the mills included in the data base upon which the
effluent limitations were based did not include any mills
with the newer, 317 stainless steel bleach washers.
Figures 28 and 29 graphically display the size and effluent
characteristics of the bleached kraft mills for which data
were available. This figure demonstrates the apparent lack
of correlation between size of mill and raw waste flow and
BOD5. To further illustrate the point. Figures 30 and 31
show size versus flow and BODj> for the non-integrated fine
paper subcategory. An analysis of the impact on raw waste
load of the number of pulp/paper machines at mills within
the subcategories was made and the results showed that
significant correlations did not exist. As an example.
117
-------
~ co°
03 mo.
,00
uo
o
DO
00°
BLEfiCHED KRRFT SEGMENT
PRODUCTION VS BODS
x
FIGURE 28
X
X X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
17.00 314.00 51.00 68.00 85.00 102.00 119.00 136.00 153.00 170.00
PRODUCTION TON/DOT *iO'
-------
0 =
f—
\
BLE'flCHED KRRFT SEGMENT
PRODUCTION VS
FLOW
FIGURE 29
34. (
51.00 SS.C'P
PRODUCTION
8=.. 00
I ON /THY
102.00
xir;
119. OC
i3o.or
170.00
-------
N
PRGDUC
I FINE
TION VS
FLOW
FIGURE 30
o:c
C_D
o —
o
o
0 =
70.00 1HO.OO 210.00 260.00 350.00 >420.00
PRODUCTION TON/DflT
490.OC 560.00
630.00
700.OC
-------
I X
« I
O ;
"I
NI PINE
PRODUCTION VS BODS
FIGURE 31
/C.OO 140.00 ?1C.OO ?80.00 350.00 420.00 490.00 550.00 630.00 700.00
PRODUCTION TON/DRY
-------
Table 22 presents several data points for three types of
mills and shows that no significant differences due to this
factor may be detected within the sutcategories. As further
substantiation of this point, Figure 32 shows that no
significant correlation exists between number of machines
and raw waste load within the bleached kraft subcategories
which is used as an example.
Thus, age and size of mills were considered but were not
used as primary basis for subcategorization except as noted
above for the papergrade sulfite subcategories.
GEOGRAPHICAL LOCATION (INCLUDING CLIMATE)
Mills are widely dispersed throughout the United States,
from Maine to Alaska, and from Minnesota to Louisiana.
Despite this dispersion, the data from surveyed mills in the
same subcategories do not reveal significant differences in
raw waste loads as affected by geographical location.
The type and physical and chemical characteristics of wood
used in pulping processes is a function of the geographical
location; however, evaluation of the impacts on raw waste
load determined that no significant correlations exists
between the type and characteristics (as a function of
geographical location) of the wood and raw waste loads.
Mills using wet woodyard operations receive additional
allowances in the BPCTCA effluent limitations. These wet
woodyards were also discussed previously in the raw
materials section and are generally a function of
geographical location. Mills which use hydraulic debarking
are generally located in the Pacific Northwest and Alaska,
because these mills require this specialized type of
debarking due to the large diameters of the logs which they
process. Logs in other parts of the country are usually
smaller and can be debarked using drum defcarkers without the
use of water. In some cases, however, mills require the use
of water in the drum debarkers for a specific purpose such
as thawing the logs during winter months if the mill is
geographically located where winters are extreme. Thus, the
geographical location factor was examined and was taken into
account through provision of additional allowances for those
mills located where the woodyard operations necessitate the
use of operations which generate additional waste loads.
Although geographical location can have an effect upon BODJ5
removal efficiencies of biological treatment systems as a
result of temperature extremes caused by climatic
conditions, the effects of temperature variations can be
122
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Table 22
RAW WASTE BOD VS. NUMBER OF MACHINES
Mill
Code
2
3
5
112
119
150
151
262
265
Segment
Groundwood
Groundwood
Groundwood
Bleached Kraft
Bleached Kraft
Soda
Soda
Fine
Fine
No. of
Machines
1
4
8
2
8
2
7
1
6
Raw Waste BOD
kg/kkg (Ib/ton)
20,
16,
18
24.5
23.5
57
49.5
9
11
(41)
(33)
(36)
(49)
(47)
(114)
(99)est,
(18)
(22)
123
-------
12
10
(O
LU
o
U. 6
O
tr.
UJ _
00 5
A A
10 20 30 40 50 60
(20) (40) (60) (80) (100) (120)
AVERAGE ANNUAL RAW WASTE BOD
Kg/KKg (LB/TON)
FIGURE 32
BOD VS NUMBER OF MACHINES
BLEACHED KRAFT SEGMENT
124
-------
minimized through effective design and operation of the
biological treatment facilities (See Section VII) . Any
temperature effects upon adequately designed and operated
facilities are taken into account in the determination of
effluent limitations as discussed in Sections VII, IX, X,
and XI.
Geographical location was, therefore, considered but not
used as a basis for subcategorization.
125
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SUBCATEGORY RATIONALE
The rationale for the development of each subcategory is
discussed below:
Bleached Kraft Subcategories
The raw waste characteristics generated during pulp and
paper manufacturing can be considered to be affected by two
basic variables: (1) process variables and (2) waste water
variables. The process variables relate to the specific
manufacturing operations used to produce the desired final
product. Waste water variables relate to the recovery and
reuse of individual process waste streams, which include
internal control measures used to recover chemicals and
fibrous materials. The process variables generally
determine to what extent waste water can be reused, because
of the desired end product requirements.
The process variables relate to the specific manufacturing
operations used to produce pulp and paper from fibrous raw
materials. The major component parts of the process
variables include: (1) wood preparation, (2) pulping, (3)
bleaching, and (4) product-making. The variation in these
processes, which are necessary for different products,
produce distinct differences in waste water characteristics.
The condition of the wood (chips vs. logs or frozen) that is
received at the mill may vary the wood preparation processes
and affect raw waste load. A primary process variable in
wood preparation operations which has an impact on waste
water characteristics is the use of debarking processes
requiring water as an integral part of the process such as
hydraulic debarking. The primary process variable for
pulping is the degree of cooking which can be characterized
by such measurements as yield loss and KAPPA number. The
factors affecting pulping include (a) the cook
characteristics, such as the length, and temperature and
pressure, and (b) the strength and chemical makeup of the
cooking liquor. The primary process variable for bleaching
is the degree of bleaching. The factors affecting bleaching
include (a) the bleaching sequence (number and type of
bleaching steps) and (b) the individual bleach stage
characteristics, such as the strength and chemical make-up
of the bleach liquor and the length of the bleach (i.e.
time, temperature, and pressure). The primary process
variable for product-making is the final product qualities.
The factors affecting the waste water characteristics in the
papermaking process variable include the production of
market pulp or paper. For mills producing paper, the types
and quantities of additives used in determining the
126
-------
qualities of the final product can have an impact on the
waste water characteristics.
The waste water variables relate to the recovery of
chemicals and fibers and to the reuse of process waters. As
mentioned above, the waste water variables are a function of
the process variables since some recovery and reuse
practices are limited by the specifics of the raw materials,
manufacturing process, and final end product qualities. The
extent of the recovery and reuse procedures has a direct
impact upon the raw waste load. These recovery and reuse
procedures are discussed in Section VII and VIII and include
such items as the following: capacity of the brownstock
washers for recovery of the black liquor; capacity of the
evaporators; spill control and reuse systems for recovery of
such items as liquor spills, evaporator boilout, and
evaporator carryover; screen room water reuse and knots
recovery; landfill of grits and dregs; recovery of lime mud;
bleach plant jump stage count;ercurrent washing; and save-
alls and the reuse of white water.
The above discussion of process and waste water variable was
considered as a basis for subcategorization of the bleached
kraft mills. As is apparent from the discussion, the
process variables are used as the primary basis for
subcategorization since the process variables account for
variations in raw materials, manufacturing operations, and
final products. The waste water variables are considered
primarily in the establishment of raw waste loads for each
subcategory and in developing effluent limitations. These
are discussed in Sections V, IX, X, and XI. In addition to
evaluating the process variables, factors such as age and
size of mills and geographical location were examined to
determine any impacts upon the process variables which were
of significance and which may have an impact upon the waste
water characteristics. In the examination of the process
variables for the purpose of subcategorization, any
relationship between the recovery and reuse procedures used
specifically by one type of manufacturing operation were
applied to only that specific type of manufacturing
operation.
Mills using the bleached kraft process were subcategorized
into four separate subcategories and each is described by
the final product manufactured: (1) dissolving pulp, (2)
market pulp, (3) fine papers, and (1) BCT papers. The
process variables are inherent in sufccategorization by final
product since the product qualities relate directly to the
process variables. After evaluating the factors discussed
earlier, it was concluded that the most significant effects
127
-------
TABLE 23
BLEACHED KRAFT
BRIGHTNESS VS. BLEACHING
Brightness Bleach
% G.E. Sequences
to 75 CEH
75-80 CEHH, CED, CHEH
80-85 CHEH, CEHEH, CED, CEHDP, CEHD
85-90 CEHD, CHED, CEDED, CEHDP
90 plus CEHEDP
128
-------
TABLE 24
BRIGHTNESS (GE, X) VS BLEACH STAGE
KRAFT PULPING
Wood type:
Sequence:
Brightness
Sequence:
Brightness
Sequence:
Brightness
50% Jack pine
Unbleached
27.7
Unbleached
27.7
Unbleached
27.7
& 50
C
C
C
Ponderosa Pine
H D
55
H
63.5
D
84.2
D
66.8
D
89
P
90.3
D
88.0
Wood type:
Sequence:
Brightness
Unbleached
23.2
Southern Pine
C E
26.1
H
68.7
D
88
P
92.2
Wood type: Southern Hardwoods
Sequence: Unbleached C E H
Brightness 22.1 37.8 40.8 74.3
1.2
P
90.6
Wood type: West Coast Softwoods
Sequence: Unbleached C
Brightness 23.1
Sequence: Unbleached C
Brightness 23.1
E
26.3
H
74.4
D
60.5
D
86.1
E
64.7
P
89.7
D
88.8
129
-------
O""- I
o
o
!L ERC;HEy K hHF-' [ S E C M r N i
BRIGHTNESS VS FLOW
FIGURE 33
i *
o; *
^
^0.00 81.00 82.00 83.00 84.00 85.00 86.00 87.00 88.00 89.00 90.00
BRIGHTNESS
-------
CO
QDo_
in
o
BLEHCHED KRRFT SEGMENT
BRIGHTNESS VS BODS
FIGURE 34
x
X
X
x
x
X
X
X
X
X
"eo.30
si. oo
ss.?-: ay.co es. oo ?ri.ao
BP ! GH • N-SS
87. oo ae.oo eg.oo 90.00
-------
TABLE 25
BLEACHED KRAFT MILLS
BRIGHTNESS AND BLEACH PLANT SEQUENCE
Mill
100
101
102
103
104
104
105
106
107
108
109
110
111
112
113
114
116
117
118
119
120
121
122
124
125
125
125
125
126
127
127
130
131
131
132
133
134
135
136
138
139
140
141
141
143
164
164
182
185
186
187
510
510
80,88
85
84
84-85
90
65,80
88-90
90
90
88
92
88 - HW
Brightness(GE,S
83
84-88
87
86-88
85
80
85
89
89
84-92
80-87
84 - SW,
82-85
90
88
88-92
87
81-83
84
82.5
85
87
80-86
88
69-72
80
78-80
87-89
87-89
87-92
87-92
88-91
80
85
84
87
86
88
78-84
Bleach Sequence
CEHDH
CEHDH
CEDED
CEHED
CEHED
CEHH
CEHDED - SW, CEHDD - HW
CEDED
CEDE/HD
CHEDED
CEDED
CEDED
CEHDED - SW, CEHED - HW
CEDED
CHDED - HW, CEHDEDD - SW
CEHDED
CEHD
CEHH
CEHD
CHHD
CHEHED - SW, CHEDH - HW
CEDED - SW, CEHED - HW
CEDED
D/COD
CEH
CED
CEHH
CEHED
CEDED
CEHDED
CEHD, CEHDED
CEHED
CEHED
CEHDED
CEHP
CEHHD
CEDED - SW, CEHD - HW
CEDED
CEHDH - SW, CHEHD - HW
CEHHD
CEDED
CEHED
CEHED
CEHH, CEH
CEHD
CEHDED
CEH
CEHD
CEHDEDDS
CEHDED
CEDE/HD
CEHEDH
C/DEHDEDHHS
SW
HW
Softwood
Hardwood
132
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upon effluent characteristics are process and product
factors rather than several other factors such as age, size,
location or raw materials.
The effect of bleaching upon raw waste loads was evaluated
and found to have some discernable effect upon raw waste
loads, but specific relationships between the degree of
bleaching and raw waste loads could not be documented.
Although brightness test results indicate the extent of
bleaching of a given pulp, there is no data to substantiate
a relationship between yield loss and brightness throughout
the subcategories. Depending on the final product and the
way individual mills chose to implement their bleaching
technology, a variety of bleaching sequences and chemical
applications have resulted. The most critical stage in the
bleaching process is the chlorination stage, which is
universally applied as the first stage throughout the kraft
subcategories. The chlorination stage in conjunction with
the second stage, which is either caustic soda or
hypochlorite, accounts for the majority of the yield loss in
the kraft bleaching process. The yield loss at this stage
of the bleaching process could be expected to be about the
same regardless of final pulp brightness accomplished by
chemical application in subsequent stages. The incremental
difference in yield is not significant enough for a given
pulp to correlate with brightness. Table 23 is presented as
an example of the different brightness levels that can be
achieved with the various stages of bleaching of hardwood
pulps, and to show the decreasing incremental increases in
brightness levels with added bleaching stages (2). Further
examples are shown in Table 2H which shows the brightness
levels associated with each stage of bleaching for various
wood types (308) .
Consideration was given to subcategorization based upon the
number and type of bleach stages and corresponding
brightness levels. Figures 33 and 34 illustrate the lack of
correlation between brightness levels and raw waste flow and
BOD5, respectively. Data in Table 25 shows that mills
producing pulp for use in their own integrated paper
operations generally produce pulps in the 80-88 brightness
range whereas market pulp mills producing 100% pulp for use
elsewhere generally accomplish higher brightness in the 88-
92 brightness range. Examination of available data
indicated that integrated bleached kraft mills generally
have lower raw waste loads than mills producing market pulp.
Dissolving pulp is cooked and bleached to a higher degree
than regular market kraft pulp and pulp mill spent liquor
which reaches the raw waste stream will contribute a
133
-------
proportionally higher amount of BODS than either market pulp
or pulp from an integrated operation. Table 26 summarizes
the brightness and bleaching sequences used by mills in the
bleached kraft market pulp and dissolving pulp
subcategorie s.
Table 25 indicates that mills producing kraft pulp for
integrated paper operations as well as mills producing kraft
pulp for market both use a large variety of bleach
sequences. Available data indicate that with the exception
of kraft pulp produced for dissolving applications, there is
no basis for subcategorization of bleached kraft mills based
on bleaching sequences regardless of the end use of the
bleached pulp. The bleached kraft mills producing
dissolving pulp, bleach to a higher brightness than regular
market pulp mills, but as previously mentioned, their
pulping process contributes a higher degree of BOD5_ to the
raw waste load.
Consideration was also given to subcategorization of mills
producing semi-bleached kraft pulps for use in newsprint and
other paper products. However, using the same rationale
applied previously in that final brightness is not a
significant measure of the effect of bleaching on raw waste,
and the fact that many of the mills producing semi-bleached
kraft also produce fully bleached pulp, establishment of a
separate subcategory could not be justified.
Mills that produce bleached kraft papers can generally be
classified by the amounts of additives in the paper grades.
These mills can be divided into two general groups; those
that use relatively large amounts of additives such as
starch, resins, and fillers and those that use very few
additives. Available data indicates that raw waste loads
from mills producing high additive bleached kraft grades,
primarily fine papers, are lower than mills producing
significantly lower additive grades such as paperboard,
coarse papers, and tissue type products made from bleached
kraft. It would be expected that mills producing fine
papers would have a higher BODji raw waste load than mills
producing BCT papers because of the BOD5 associated with
such additives as starches. However, it appears that
evaluation of EOD5_ data on a kg/kkg (Ibs/ton) basis results
in the additional BOD5 associated with the papermaking
additives is more than offset by the additional weight of
the additives in the final product. In addition, process
variables have some impact on the raw waste loads between
fine and BCT papers manufacture since end product qualities
relate the process variables. Raw wastes generated during
the manufacturing of products in each of these two groupings
134
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TABLE ?F
BLEACHED KRAFT SUBCATEGORIES
MARKET PULP AND DISSOLVING PULP MILLS
BRIGHTNESS LEVELS AND BLEACH PLANT SEQUENCES
Mill
114
126
130
139
140
185
186
187
108
127
510
510
Brightness(G.E.,%)
Bleached Kraft Market Pulp Subcategory
88-92
87-89
88-91
88
85
88-90
90
90
Bleach Sequence
CEHDED
CEDED
CEHED
CEDED
CEHED
CEHDEDDS
CEHDED
CEDE/HD
Bleached Kraft Dissolving Pulp Subcategory
84-92 CHEDED
87-92 CEHD, CEHDED
88 CEHEDH
92 C/DEHDEDHHS
135
-------
of papers are significantly different and are shown in Table
16.
The process factors as mentioned above have some impact on
raw waste load between mills producing fine papers from
bleached kraft and those producing paperboard, tissue, and
coarse papers from bleached kraft. The manufacturing
processes and pulp mill operating parameters are directly
related to the required qualities of the final product.
However, available data does not show this impact to be
significant although it is acknowledged and inherently
considered through subcategorization on the basis of final
products produced.
Sulfite Subcategories
Mills using sulfite pulping to produce pulp and paper were
divided into the following subcategories:
1. Papergrade Sulfite: Blow Pit Washing
2. Papergrade Sulfite: Drum Washing
3. Dissolving Grade Sulfite Pulp
Examination of the process variables of the 30 sulfite mills
distinctly separated two groups of mills: (1) mills
producing papergrade pulp and paper and (2) mills producing
dissolving pulp. Further examination resulted in
subcategorization of the papergrade sulfite mills on the
basis of type of pulp washing system, i.e., blow pit or drum
washing. The rationale used in determining these
subcategories is discussed below.
The impact of woodyard operations on raw waste loads were
discussed previously in this section and the previous
discussion also applied to sulfite mills. A total of 12
sulfite mills of the 30 presently operating in the U.S. use
wet woodyards for all or some of their wood preparation. As
discussed in Section V, only two mills use wet woodyards for
processing all of their fiber source (roundwood). The other
mills with wet woodyards purchase chips varying from 10 to
66% of their total fiber source. In addition, several mills
use wet debarking for only a portion of their roundwood
using dry processes for the rest. Because of these varied
woodyard operations and since woodyard operations are
similar for all subcategories which use wood as the basic
raw material, subcategorization of sulfite mills based on
woodyard operations was not suitable. Instead, provisions
were established for mills using wet woodyard operations
which in effect increases the effluent limitations for the
mills using wet woodyards in an amount which would 'be
136
-------
attributable to the additional sources of waste water
generated in the woodyard.
Aside from the woodyard operations which are taken into
account through additional provisions, the primary variables
which can have impacts on raw waste load from sulfite mills
include the following: (1) digestion, (2) washing and
screening, (3) spent sulfite liquor evaporation and
recovery, (4) bleaching, and (5) product making.
For papergrade sulfite mills, the degree of spent liquor
recovery was determined to be the most significant factor
influencing a mill's raw waste load. Only three of the 30
sulfite mills do not recover any of the SSL. These mills
wash the pulp in blow pits and discharge the washwater to
the effluent discharge. This operation has the highest
effluent BODji and is not considered BPCTCA. About half of
the sulfite mills wash in blowpits but recover the spent
liquor. Use of blow pit washing systems generally result in
recoveries of the SSL ranging from 80 to 85% whereas vacuum
or pressure drum washing achieves recoveries of SSL of 90 to
98%. Maximum recovery of the SSL is critical to minimizing
raw waste loads, and therefore, mills using blow pit washing
systems generally have higher raw waste loads than mills
using vacuum or pressure drum washing systems. Therefore,
separate subcategories were established for papergrade
sulfite mills with blow pit and drum washing systems.
Several mills are using vacuum drum pulp washing systems but
are achieving SSL recoveries similar to those achieved by
mills with blow pit washing systems. This may be attributed
to operating the recovery system beyond its design capacity.
Also significantly affecting raw waste from sulfite mills is
the type of cooking liquor used in pulping, i.e., acid
sulfite or bisulfite. Analysis of the recent survey data
suggested an added allowance for raw waste loads resulting
from acid sulfite cooking. The effect on raw waste load is
not as great as the type of pulp washing but the difference
is significant and thus, an allowance for acid sulfite
cooking of papergrade pulp is included in the effluent
limitations. One reason for the higher waste load from acid
sulfite pulping is the higher BOD5 load in the evaporator
condensates than in the condensate from bisulfite liquor
which is at a higher pH. Acid sulfite cooking liquor
contains a high percentage of free SO^ (excess SO2) and has
an initial pH of approximately 1-2. The base is usually
calcium but may also be a soluafcle base such as sodium,
magnesium, or ammonium (2). Bisulfite cooking liquor
contains a predominance of bisulfite ion in the 3 to 6 pH
range with little or no true free (excess) SO2:. The base
137
-------
must be more soluable than calcium, i.e., sodium, magnesium,
or ammonium (2).
The use of barometric condensers or the use of surface
condensers is another variable that can have an impact on
the raw waste load. As shown in Table 27, approximately
half of the papergrade sulfite mills have surface condensers
and half have the older direct contacting barometric
condensers. Three mills have no condensers (those with no
SSL recovery). The primary impact upon raw waste load by
the type of condensers used is upon the raw waste flow since
the raw waste BOD5 would be expected to be similar for
either type of condenser. The use of barometric condensers
usually result in higher flows to treatment than the use of
surface condensers (29). Cooling water from surface
condensers can be used as process water throughout the
plant. Since surface condensers are not considered a BPCTCA
technology for papergrade sulfite mills, an allowance for
flow was made for mills with barometric condensers.
The use of bleaching processes can be a significant process
variable which can have impacts upon raw waste loads.
Sulfite pulp in contrast to kraft pulp is relatively light
in color with brightness levels commonly in the low 50's (%,
G.E.) prior to bleaching. Because of this, bleaching of
sulfite pulp is not as extensive as in bleaching kraft pulp,
and papergrade sulfite mills commonly use one or three
stages of bleaching. Bleaching at sulfite mills producing
dissolving pulp is discussed later. The bleach plants at
papergrade sulfite mills, as discussed in Section V, most
commonly are CEH and a number of mills have used one stage
bleaching, H. Mills producing products such as newsprint
which do not require high brightness levels do not bleach
pulp and thus do not have the added source of raw waste load
from the bleach plant. Consideration was given to
establishing subcategories similar to kraft subcategories of
unbleached papergrade sulfite and bleached papergrade
sulfite; however, the available information and data were
inadequate to determine the precise impact upon raw waste
loads of not using bleaching operations. Instead of
establishing a separate subcategory for unbleached sulfite
mills, the effluent limitations were based upon raw waste
loads by mills which use bleaching processes (i.e., the
higher raw waste loads).
Consideration was also given to subcategorization based upon
the degree of bleaching since it would be expected that
higher degrees of bleaching (i.e. higher brightness levels)
would result in higher raw waste loads. Similar to the
previous discussion of the bleached kraft subcategories,
138
-------
TABLE 27
PAPERGRADE SULFITE PROCESS VARIABLES VS. RAW WASTE LOAD
Mill
069
006
007
052
051
053
058
070
068
056
062
066
065
067
063
071
059
064
Washing
Blow Pit(BP) Yield
Drum(D)
BP
D
D
BP
BP
D
BP
BP
BP
BP
D
D
D
BP
BP
BP
D
BP
I
47
44-68
46
43
48
43
43
50
47
45
45
47
47
54
43
Cooking Evaporator
Liquor Liquor Condenser Raw Waste
Recovery Acid Sulfite(A) Barometric(B) Flow
Base
CA/NH3
Mg
Mg
NH3
NH3
NH3
NH3
CA
NH3
CA
NH3
CA
NH3
NH3
CA
CA
Mg
CA
X
0
98
98
85
81
98
0
85
50
70
90
95
90
45
86
70
95
84
Bisulfite(B)
A & B
B
B
B
A
B
A
B
A & B
B
B
A
B
A
A
A
B
A
Surface (S)
None
S
B
B
B
S
None
B S
S
B
S
S
B
B
B
S
S
B
BODS
kl/kkg(kgal/con) kg/kkg(lbs/ton)
208
117
176
170
251
87
229
_
254
231
174
186
197
384
199
208
173
-
(50.
(28.
(42.
(40.
(60.
(20.
(55.
{ -
(61.
(55.
(41-
(44.
(47.
(92.
(47.
(49.
(41-
( -
0)
0)
1)
8)
2)
8)
D
)
0)
3)
7)
7)
2)
0)
8)
9)
4)
)
450
61
44
79
114
95
450
107
112
116
74
192
77
120
89
121
110
105
,0
.5
.9
.0
.0
.5
.0
.0
.0
.0
.5
.0
.5
.0
.0
.0
.0
.0
(900.0)
(123.0)
( 89.7)
(158.0)
(227.0)
(191.0)
(900.0)
(214.0)
(223.0)
(232.0)
(149.0)
(383.0)
(155.0)
(240.0)
(178.0)
(242,0)
(220.0)
(210.0)
-------
Table 28 illustrates the incremental increases in brightness
levels associated with each stage of bleaching for hardwoods
and softwoods. The two examples shown are quite similar in
the increases in brightness through each stage of bleaching.
As discussed previously, most of the papergrade sulfite
mills use three stages of bleaching (CEH) which would
correspond to the first three stages of bleaching in Table
28. It would be expected that raw waste loads would be
slightly higher from mills using three stages of bleaching
than mills using one stage; however, the data presented in
Section V do not show significant differences in raw waste
loads between mills using one stage or three stages of
bleaching. It was determined that the primary impact of
bleaching is if bleaching operations are used or are not
used.
The type of product manufactured by papergrade sulfite mills
is a process variable which appears to have a relatively
insignificant impact on raw waste load when compared to the
other impacts on raw waste load, such as the degree of SSL
recovery. This is in contrast to the bleached kraft
subcategories in which the type of product was determined to
be a significant process variable. This difference can be
attributed to the spent liquor recovery practiced at bleach
kraft and sulfite mills and to the relative magnitude of the
raw waste loads at two types of mills as discussed
previously and as can be observed in Table 16.
Consideration was given to subcategorization of papergrade
mills based upon the products of newsprint, fine papers,
tissue papers, and market pulp. Sulfite mills producing
newsprint as discussed previously generally do not bleach
their pulp, commonly operate in conjunction with groundwood
pulping, and representative data were not available. It was
determined that these mills could be best included in the
papergrade sulfite subcategory which has effluent
limitations based upon raw waste loads representative of
mills using bleaching processes. Sulfite mills producing
tissue papers have similar raw waste loads to sulfite mills
producing fine papers as shown in Section V. Thus,
subcategorization of mills producing fine papers could not
be justified. Market pulp mills were considered as a
separate subcategory. Unlike bleached kraft, however, in
which higher raw waste loads can be attributed to purer
grades of pulp (i.e. higher degrees of washing, cleaning and
bleaching), the waste loads associated with market sulfite
mills are affected more by the degree of SSL recovery. As
discussed in Section V, six mills produce market pulp but
four of these mills also produce other products. Of the two
mills producing 100% market pulp, one mill (Mill 058) has no
SSL recovery. This leaves only one mill (Mill 056)
140
-------
Table 28
Brightness (G.E.%0) vs Bleach Stage
Sulfite Pulping
Wood type: Northeast Softwoods
Sequence: Unbleached C E H D
Brightness: 52.1 50.9 60.3 82.7 92.9
Wood type: Northern Harwoods
Sequence Unbleached
Brightness: 52.4
C
53.8
E
61.9
H
83.7
D
94.3
141
-------
producing market pulp with waste loads representative of
BPCTCA. Data from this mill are not significantly different
from other papergrade sulfite mills; therefore,
subcategorization based upon final product was not
justified. As previously developed, additional allowances
are provided for sulfite mills with barometric condensers
and for mills using acid sulfite cooking liquor. In
addition, an allowance was provided for sulfite mills with
continuous digesters.
There are six sulfite mills producing dissolving grade
sulfite pulp as discussed in Section V. The determination
of the dissolving sulfite subcategory was on the basis of
products produced. Dissolving pulps are highly purified
forms of cellulose which are used in the manufacture of
rayon, cellophane, methyl cellulose, ethyl cellulose, nitra-
cellulose, cellulose acetate, and other cellulose
derivatives. Dissolving sulfite differs from papergrade
sulfite pulp in that it contains a higher percentage of
alpha cellulose and a lower percentage of hemi-celluloses.
The extra degree of purity is obtained primarily by hot
caustic extraction during the bleaching operations. Also
the cooking conditions are sometimes somewhat more severe
than for papergrade pulp (i.e., a higher cooking temperature
and a shorter cooking time). The unbleached yields for
dissolving pulps are about the same as for papergrade
sulfite pulp. Most of the additional purification required
by the dissolving pulps comes in the bleaching, more
specifically in the hot caustic extraction stage. For this
reason the shrinkage in the hot caustic extraction is the
most important factor in identification of the different
grades of dissolving pulps.
There are four basic grades of dissolving wood pulp which
are commonly produced by the sulfite process. These are:
(1) nitration grade, (2) viscose grade, (3) cellophane grade
and (4) acetate grade. The properties, mainly the alpha
cellulose content and the viscosity of each of these grades
is varied to provide the properties which are desirable for
its particular end use. The base effluent limitations for
sulfite dissolving pulp were established for nitration grade
pulp, and additional allowances because of the higher raw
waste loads are allowed for viscose, cellophane and acetate
grades.
Nitration grade dissolving sulfite pulp has a hot caustic
extraction shrinkage of 8-12% and an alpha cellulose content
of 92% or higher. For most end uses the purity of nitration
grade pulp is not as critical as for acetate grade pulps.
One exception to this is for explosive grade pulp which
142
-------
requires an extremely pure pulp with an alpha cellulose
content of 98%. Nitration grade pulps find their end uses
entirely in non-fiber purposes, which are used primarily in
the manufacture of plastics and lacquers.
Viscose grade dissolving sulfite pulp has a hot caustic
extraction shrinkage of 13-17% and is used in the
manufacture of rayon, which is the largest use of dissolving
pulp. Pulp to be used for rayon manufacture generally has
an alpha cellulose content in the range of 88 to 91%.
Cellophane grade dissolving pulp has a hot caustic
extraction shrinkage of 17-23% and an alpha cellulose
content of 89% and higher. The most important property of
this pulp is its solution viscosity, because it determines
the viscosity of the casting solution. Uniformity of
viscosity is essential (1A - Heuser, The Chemistry of
Cellulose, 1947). A viscosity value of 20 centipoises (cp)
(3) is standard. The difference between the cellophane and
viscose grades is that cellophane grade pulp undergoes a
slightly higher degree of hot caustic extraction.
Acetate grade dissolving sulfite pulp has a hot caustic
extraction shrinkage of 24% or higher. Acetate pulps
normally have an alpha cellulose content of 95.0-96.5 (3).
Acetate grade pulp is used for both textile fiber purposes
and for non fiber purposes. The fiber uses include regular
tenacity yarn and acetate filament yarn. The requirements
of pulp used in the manufacture of cellulose acetate are
much stricter than those for rayon grades. This pulp must
be relatively free of pentosans, degraded cellulose and
other non-cellulosic materials. These materials in the pulp
produce a hazy solution, lower the yield, reduce the
recovery of chemicals and impare the physical and chemical
properties of the cellulose derivitives.
In summary, since the various grades of sulfite dissolving
require different levels of pulp purity and since these
specifications determine the process variables to be used,
and significantly impact the raw waste loads, the dissolving
sulfite subcategory was determined on the basis of products
produced and additional allowances are provided for the
different grades of pulp.
The geographical location was also considered in determining
appropriate subcategorization for sulfite mills. As
discussed previously, the allowance for wet woodyards is
also related to geographical location since woodyard
operations are frequently specific to the size of logs
available to the mill or the climate at the mill. Many
143
-------
sulfite mills are located in Northern climates and thereby
the design and operation of external treatment facilities
should take into account the effects of extremely cold
temperatures upon biological treatment effectiveness.
Activated sludge systems with short detention times are
generally considered adequate to overcome any problems
associated with temperature. In addition to the need for
activated sludge systems to allow for climatical extremes, a
number of mills have limited availability of land to be used
for the biological treatment systems. These mills will
probably use activated sludge systems which require much
less land than aerated stabilization basins (ASB). However,
activated sludge systems tend to cost more than ASBs and
therefore, costs of activated sludge systems were determined
in addition to costs of aerated stabilization basins for
each of the subcategories as shown in Section VIII.
Groundwood Subcateqories
Mills using groundwood pulping were sufccategorized into four
separate subcategories based upon process variables. These
subcategories include the following: groundwood: chemi-
mechanical, groundwood: thermo-mechanical, groundwood: fine
papers, and groundwood: CMN papers. Distinct differences in
the manufacturing process between these subcategories result
in differences in raw waste characteristics and are shown in
Table 16.
Groundwood pulp contains essentially all of the material
contained in the basic wood which unlike chemical pulps
gives very high yields (90-98%). Since extensive bleaching
is not done on groundwood pulps, the major variables are
reduced to the pulping process and the type of paper
produced. The most significant process variable for mills
using chemi-mechanical and the thermo-mechanical process is
the pulping process. Mills producing paper by the chemi-
mechanical (or cold soda) use a pulping process involving a
short digestion of the wood chips with a cooking liquor
followed by mechanical refining at atmospheric pressure.
Mills using the thermo-mechanical refining also use a
"digestion" process prior to mechanical refining but the
differences are that the thermo-mechanical cook is much
shorter, no cooking liquor is usually used (generally a
steaming process), and the first stage of mechanical
refining is usually done under pressure.
The difference in raw waste characteristics are significant
between the two processes as the BOD5 characteristics for
the chemi-mechanical and thermo-mechanical processes are
144
-------
95.5 kg/kkg (191 Ibs/ton) and 39.2 kg/kkg (78.U Ibs/ton) ,
respectively.
The most significant process variable for mills using the
groundwood process (without any digestion or cooking stage)
is the type of paper produced. No significant effects upon
raw waste characteristics of the type of groundwood process
used, stone or refiner, are shown by the available data. In
addition, the effects of brightening were considered as a
basis for subcategorization but were eliminated by
developing the subcategorization based upon representative
mills that do use brightening as part of their process.
Thus, the few mills that do not brighten their pulps would
have lesser raw waste characteristics than the subcategory
averages. Table 29 presents brightness levels and RWL for
groundwood mills and as shown, mills producing CMN papers
have brightness levels significantly lower than mills
producing fine papers. Any impacts upon RWL or brightening
are thus taken into account in establishing two
subcategories. Mills using the stone or refiner groundwood
process produce a wide array of products including fine
papers, newspapers, coarse papers, and molded pulp products.
The distinction between these products is primarily in the
quantity of additives used to produce the desired product
qualities. Coarse papers (C), molded pulp products (M), and
newspapers (N) use very few, if any, additives whereas mills
producing fine papers use additives which make up 10 to 35%
by weight of the final product. In addition to differences
in the additives used to produce either fine papers or CMN
papers, the type of pulp used to produce these types of
papers differs distinctly between the two types of mills.
The pulp manufactured by groundwood pulping is characterized
by short fibers. In order to produce papers with adequate
strength, a blend of the short fibers with longer fibers
produced by chemical pulp (i.e. kraft or sulfite) is
necessary. The proportion of short fibers to long fibers is
determined by the qualities of the final product. Products
such as CMN papers require up to 30% long fibers whereas
higher grade products such as fine papers require about 50%
long fibers. Thus, groundwood mills producing CMN or fine
papers characteristically use purchased pulp which is
blended with their groundwood pulps in varying proportions
depending upon the type of paper being manufactured.
Therefore, the significant process variables that were
determined for groundwood mills were related to the final
product which in turn determined the amount of additives
used and the proportions of groundwood and purchased pulps
used. On the basis of the type of paper produced, separate
subcategories were thus established.
145
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Table 29
Groundwood
Raw Waste Load vs. Brightness
Mill
.P.
01
Flow
kl/kkg(kgal/ton)
BOD5
kg/kkg(!Fs/ton)
Brightness
Subcategory
2
3
5
13
19
20
8
9
10
14
15
16
17
99.7
106.0
97.6
107.0
78.8
83.0
114.0
53.0
113.0
108.0
108.0
886.3
12.5
(23.9)
(25.5)
(23.4)
(25.7)
(18.9)
(19.9)
(27.4)
(12.7)
(27.0)
(25.8)
(25.8)
(20.7)
( 3.0)
18.6 (37.1)
16.3 (32.5)
16.6 (33.1)
13.5 (27.0)
20.9 (41.8)
12.8 (25.6)
18.9 (37.7)
18.1 (36.1)
21.5 (43,0)
(6.6 (13.2)
19.5 (39.0)
19.1 (38.2)
9.8 (19.5)
74
73
68
73
80
73
60
57
57
55
60
60
75
Fine
Fine
Fine
Fine
Fine
Fine
CMN
CMN
CMN
CMN
CMN
CMN
*
Mill 17 produces market pulp
-------
Soda Subcateqory
Because of similarities of the process variables among the
soda mills, one subcategory was developed. Each mill
produces fine papers by the soda pulping process. In
addition, the mills purchase market pulp to supplement their
own manufactured pulp in making fine papers. Each of the
mills is relatively old with the newest mill, mill 150 which
has recently closed, being built in 1923. The bleaching
operation at these mills is similar except that mill 150 has
a shorter bleach sequence and thereby does not bleach to as
high a brightness as mills 151 and 152. Higher bleaching
generally results in higher effluent loads but, as the
discussion of bleaching for bleached kraft mills indicated,
the majority of the raw waste load is generated in the first
three stages of bleaching. Mill 150 is the "newest" soda
mill with the lowest amount of bleaching yet the effluent
loads from mill 150 are higher than mills 151 and 152, and
this is probably related to the recovery factor similar to
bleached kraft mills. Thus, one subcategory was developed
because the process variables were similar and the
differences in the raw waste characteristics are related to
the waste water variables.
Deink Subcateqory
One subcategory which includes all deink mills was
established for mills which deink waste papers. The deink
manufacturing process uses waste paper as its primary source
of raw materials. The purpose of the pulping process is to
separate the fibers and to remove the unfibrous materials
(i.e. papermaking additives, inks). A wide array of
products are manufactured including fine, tissue and
newspapers.
The principal effects upon raw waste characteristics are
related to (1) the type of waste paper used as raw materials
and (2) the end product qualities. The data shown in
Section V is broken into two products, fine papers and
tissue papers, and shows some differences in raw waste
characteristics between mills producing the two product
types. It should be emphasized, however, that deink mills
commonly purchase pulp to be used as a supplementary source
of fiber and the data presented in Section V does not
represent 100% deink pulp use at each of the mills except as
noted. In addition, several mills use waste paper which is
not deinked as a third source of fiber. Consideration was
given to subcategorization based upon the type of product
produced, but raw materials generally have a more
significant impact upon raw waste characteristics. Because
147
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market, conditions for waste paper change with demand for
available waste paper supplies, raw wastes from deinking
operations can be affected. The raw wastes are also
affected by the relative percentages of virgin fiber and
waste paper. Therefore, effluent limitations and standards
were based upon mills using 100% deink pulp for the
production of final products. (See Section V) .
Non-Integrated Paper Mills Subcategories
The non-integrated paper mills were subcategorized into
three subcategories based upon process variables. The three
subcategories include non-integrated mills using purchased
pulp to produce (1) fine papers and (2) tissue papers and
(3) non-integrated mills using waste paper without deinking
to produce tissue papers. In addition a number of non-
integrated paper mills were excluded from this study because
of a lack of an adequate data base upon which subcategories
and effluent limitations could be established. Effluent
limitations will be developed for these mills at a later
date. Included in this group are non-integrated paper mills
producing coarse papers and specialty papers. Non-
integrated mills for which adequate data were available can
generally be divided into mills that use relatively large
amounts of papermaking additives (i.e. clays and fillers,
wet strength agents, starches, and rosins) and mills that
use very few additives. The products made by these two
types of mills can be classified as either fine papers
(relatively more additives) and tissue papers (relatively
few additives). Additional raw waste load generally results
from the use of additives, such as the use of starches which
is a source of BODJ5. Also, mills producing fine papers use
upwards of 8 to 10% by weight of additives and frequently as
much as 33% additional weight is added to the sheet of
paper. Consideration was given to subcategorization of
mills producing fine papers based upon the amount of
additives used, but no significant relationships between the
amount of additives and raw waste characteristics could be
determined. Figures 35 and 36 illustrate the lack of
correlation between clays and fillers (C&F%) in the sheet of
paper and the raw waste characteristics. Each point on the
figures represents the data from a single non-integrated
fine paper mill.
Therefore, the use of additives in the papermaking process
to produce the desired end products of either fine papers or
tissue papers was determined to be the most significant
factor upon raw waste characteristics, and the subcategories
of non-integrated fine papers and non-integrated tissue
papers were developed accordingly. Even though the use of
148
-------
BODS IBS/TON
J.OO M.OO 8.00 12.00 16.00 30.00 24.00 28.00 32.00 36.00 MO.00
& 1 i_ i 1 i _i j _j J j
01
o
vl_
O
X
K X
M <
PI »
rn
K
-------
o-
o
NI FINE
% C + F vs FLOW
FIGURE 36
5.00
7. SO iO.OO 52.10 5-5.00
Z C+F
17.50
20.00
2?. 50
25.00
-------
additives by mills producing fine papers is an added source
of BOD.5 and over those mills producing tissue papers, the
average BOD5 raw waste load for NI fine paper mills is 10.75
kg/kkg (21.5 Ibs/ton) which is less than the average BOD5
raw waste load for NI tissue paper of 11.5 kg/kkg (22.9
Ibs/ton) . It appears that the added sources of BOD5_
(additives) at NI fine paper mills are more than compensated
for by the additional weight of the additives in the sheet
of paper when examined on a kilograms of BOD5 per 1000
kilograms of product (Ibs/ton) basis.
The subcategorization of non-integrated tissue mills into
two subcategories was based upon the type of raw materials
used as a source of fiber: purchased pulp or waste paper.
The use of waste paper has significant impact upon raw waste
treatability as well as upon raw waste characteristics. The
differences in raw waste characteristics are shown in Table
16 and the differences in treatability are shown in Section
VII.
151
-------
SECTION V
WATER USE AND WASTE CHARACTERIZATION
Water is important in the manufacture of pulp and paper.
The major uses are similar 'industry-wide although the
amounts typically used may vary from subcategory to
subcategory. Data on total water use of mills in each
subcategory are available both from the mill surveys
conducted during this project and from the literature (See
list of references).
Through its contact with and transport of other raw
materials, the water absorbs other substances and is
characterized at the end of its use in a mill as waste
water. The material it ultimately contains, and the amount,
varies to some degree among subcategories as discussed in
Section IV, and from one waste stream to another in the same
mill.
To address the total water use and raw waste load character-
istics of integrated mills as represented in the bulk of the
survey data, all of the applicable subprocesses of each
pulping subcategory will be discussed as one entity. This
is in contrast to the separate process descriptions of
pulping, bleaching, and papermaking of Section III.
Two subprocesses are common to most subcategories: wood
preparation and papermaking.
In the case of wood preparation, variations in waste waters
produced result from very localized conditions, as discussed
below, and are not a function of the pulping or other
processes. Thus, the description of its contribution, which
usually accounts for a very small portion of the total
waste, applies to all pulping subcategories.
Paper, paperboard, and market pulp are made on similar
equipment within all subcategories with similar water uses
and sources of waste water. Therefore, the market pulp and
papermaking operation are also discussed in detail. In
addition, the survey data presented by subcategory will,
where applicable, include the papermaking waste stream
unless otherwise indicated.
Water usage per kkg (ton) of production has declined drama-
tically in recent years due to increased emphasis on water
reuse and reduction of fresh water uses. This is
153
-------
demonstrated in Table 30 which compares 1965 data (87) with
data from surveyed mills. While the subcategorization of
mills used in the 1965 data does not agree precisely with
that used in this report it may be seen that water use
declined substantially since 1965. For example, the average
flow of individual median flow values for bleached kraft and
sulfite segments decreased by some 20-30 percent over this
period. Data for nonintegrated mills are not included in
Table 30 because the 1965 subcategorization of these mills
is not comparable with that employed in this report. Of
course, these comparisons can only be considered as
generalizations since mill data included in the 1965 figures
are probably not all the same as the surveyed mills.
However, the point that effluent volume per kkg (ton) of
production has been significantly reduced between 1965 and
1973 through inplant reuse measures is valid.
In order to obtain an overview of levels of mercury and zinc
in waste waters, grab samples of raw waste and final
discharge streams were collected at most of the surveyed
mills and analyzed for these parameters. Tables 31 and 32
present the results of the sampling program. The data
should only be used as an estimate of the mercury and zinc
levels at each mill since the data represents only one grab
sample per mill stream.
Use of Water in Pulp and Paper Manufacture
The major process applications of fresh and reused water in
pulp and/or paper mills include where applicable:
Wood Preparation
In wood preparation, water is used for four basic purposes:
(1) defreezing logs and chips, (2) log transport, (3)
debarking operations, and (4) log and chip washing.
Pulping
Fiberizing of wood, waste paper, or purchased pulp occurs in
the presence of water in all pulping processes whether this
is accomplished in mechanical grinders, chemical cooking, or
pulpers. In mechanical processes utilizing a grindstone,
its surface is cooled, cleaned, and lubricated with a stream
of water which also carries away the pulp; the chips are
conveyed through the refiners on a stream of water in other
mechanical processes. Water is added to the digester along
with the chips in chemical pulping, and to the pulper in
154
-------
TABLE 30
WATER USE
1965 vs 1973
Type of Mill
Groundwood
Sulfite
Bleached Kraft
Soda
Deink
Flow
1965(1)
200(48)
288(69)
180(43)
290(70)
138(33)
kl/kkg (kgal/ton)
1973(2)
91.5(22)
208(50)
146(35)
108(26)
87.5(21)
(1) Reference #83
(2) Data from Surveyed Mills
Note - Groundwood Segment includes only
GW-Fine and GW-CMN mills
- Sulfite Segment includes Sulfite
papergrade
- Bleached Kraft includes BCT and
Fine mills
155
-------
Table 31
MERCURY IN WASTE WATERS
en
Subcategory
Groundwood
Sulfite
Dissolving Sulfite
Bleached Kraft
Soda
Deink
Fine Paper
Tissue
Coarse
Raw Waste
Average ppb
1.65
2.73
1.65
1.32
0.52
2.05
2.06
1.72
1.05
Averages in
Final Discharge ppb
1.11
2.81
1.65
1.71
0.39
2.68
1.89
1.09
1.54
Kg*/KKg
1.05
5.10
4.33
2.21
0.55
2.18
1.78
2.12
1.93
(lb*/ton)
(2.1)
(10.2)
(8.65)
(4.41)
(1.11)
(4.36)
(3.55)
(4.24)
(3.86)
No. of
Samples
10
3
4
22
3
6
17
12
8
*Times 10 to the minus 4 power.
-------
Table 32
ZINC IN WASTE WATERS
Subcategory
Groundwood
Sulfite
Dissolving Sulfite
Bleached Kraft
Soda
Deink
Fine Paper
Tissue
Coarse
Raw Waste
Average ppm
1.04
0.234
0.312
0.413
0.208
1.41
0.22
1.09
0.85
Averages in
Final Discharge ppm
1.88
0.175
0.312
0.211
0.369
0.62
0.33
0.161
0.104
Kg/KKg
0.19
0.011
0.10
0.031
0.016
0.076
0.018
0.024
0.013
(Ib/ton)
(0.39)
(0.023)
(0.20)
(0.062)
(0.031)
(0.153)
(0.036)
(0.048)
(0.027)
No. of
Samples
10
3
4
22
3
6
17
12
8
-------
deinking. Water is also used to prepare cooking liquors.
Subsequently, water serves to convey the pulp in a slurry to
and through the remaining operations.
Pulp Washing
Water is used to wash or separate the spent cooking liquors
from the pulp and to transport the spent liquor, the pulp,
and the wastes to their next respective operations.
Dilution
Water is used to dilute the pulp slurry to facilitate
screening, cleaning, and other processes.
Deckering
Although this is primarily a thickening operation, one of
the common practices is to use the equipment to provide a
final wash stage to separate the pulp and the spent cooking
liquors.
Chemical Recovery
In kraft and soda pulp mills water is used in the recovery
system for several purposes such as dissolving the molten
smelt from the furnace, lime mud washing, and lime kiln
scrubbing (see Section III). In sulfite recovery systems,
water is used to dissolve smelt, to absorb recovered sulfur
dioxide, and for scrubbing off-gases. This is not a
comparatively large use in either case.
Bleaching
Water is used in preparing bleach solutions and in washing
between stages and at the end of the process. The amount of
water use ranges from a simple one stage brightening of
groundwood pulp with no washing to complex five and six
stages of chemical pulp bleaching.
Papermaking
Water is used in stock preparation which may involve several
steps such as beating and refining to develop desired pulp
characteristics for specific grades of paper. It is also
158
-------
employed to dilute the furnish to appropriate consistency
for application on the paper machine, and for solution and
conveyance of additives.
Non-Process Applications
The non-process water uses include lubrication and sealing
of moving parts such as shafts and vacuum pumps, steam for
the process and space heating, cooling waters, and for
washing equipment and floor areas.
159
-------
WOOD PREPARATION
In the preparation of wood for pulping operations, there are
three general types of woodyard operations which use water
in the processing steps. These include (1) log transport by
flumes and log defreezing in hot ponds, (2) log washing and
chip washing/thawing operations, and (3) debarking of logs.
Each of these operations are discussed below along with the
characteristics of the waste water generated as a result of
the operations.
It is recognized that the different types of pulping have
considerably different yields and that in order to produce
similar amounts of pulp and paper, different quantities of
wood will be required depending upon the pulping process.
The three basic types of pulping include groundwood,
papergrade chemical pulping (kraft, sulfite, and soda), and
dissolving chemical pulps (kraft and sulfite), and they use
the following quantities of wood in producing one ton of
pulp: one cord, 1.7-2.3 cords, and 2.5-3.0 cords,
respectively (341). Thus, it follows that more wood must be
processed in the woodyard (and thus more waste water is
generated) for dissolving pulp mills than for papergrade
chemical pulping or for groundwood mills. Therefore,
consideration of the differences in yield were included in
the data analyses used to determine the raw waste
characteristics for the three types of woodyard operations.
Where data were available and the type of pulping operation
was known, the raw waste data were converted to a common
yield basis (i.e. groundwood) in order to include all
available data from various types of mills with similiar
woodyard operations in determining the raw waste loads
associated with the woodyard operations. The following
conversion factors were used in the data analyses:
Groundwood: 1.0
Papergrade Chemical Pulp: 2.0
Dissolving Pulp: 2.75
Log Transport and Defreezing Operations
In handling appreciable quantities of wood, flumes have been
found to have many advantages: there is practically no
limiting factor to the lengths of flumes in a storage yard
and they can be curved when necessary to fit the topography.
Flume velocity and flow vary according to capacity and wood
density. Softwood will travel in a flume at a velocity of
1.8 m/sec (6 ft/sec), while hardwood, which partially sinks,
will require a velocity of 2.4 m/sec (8 ft/pec) or more.
160
-------
Normal flume width for Southern pine is from 76.2 to 102 cm
(30 to 40 in.) and maximum log sizes will dictate flume
width. Water quantities will vary from 757 I/sec (12,000
gpm) in small flumes up to 1,893 I/sec (30,000 gpm) for
larger installations. Usually two pumps are used; for
example, a flume designed for 1,893 I/sec (30,000 gpm) would
have two pumps. Typical flume design and capacity would be
the following: a 213 m (700 ft.) long flume with a capacity
of 80 to 100 cords/hr of softwood, a slope of 0.167 cm/m (2
in./lOO ft.), a velocity of 1.8 m/sec (6 ft/sec), a minimum
of 1,514 I/sec (24,000 gpm), and two pumps at about 93.2 kw
(125 hp.) each.
Flume waste water, which contains various amounts of bark
and silt, is generally treated in a "bark and grit removal
system." This consists of settling chambers for grit,
traveling water screens or disc screens for removing bark
arid the necessary drag conveyors for cleaning grit chambers.
Bark from the flume can be introduced into the bark system
at any point prior to reaching the bark hog. It is not
uncommon to dump the bark back into barking drums and into
the bark collection conveyors. One disadvantage of this
method is the increased amounts of bark fines. In some
areas, grit disposal becomes a problem due to large volume.
There is always a considerable amount of very fine bark that
falls out in the grit chambers and is carried out with the
grit. A vibrating screen can be used to further separate
fine bark and grit; the grit is generally hauled away for
disposal.
Flume Effluent Characteristics
After the flume water has been used for a certain amount of
time, the water is run through the grit removal and
screening systems one last time and is then discharged. Raw
waste characteristics for flume waste water from mill 151
are shown below:
Flow: 3.2 kl/kkg GW (0.76 kgal/ton GW)
BOD: 0.38 kg/kkg GW (0.77 Ibs/ton GW)
TSS: 6.35 kg/kkg GW (12.7 Ibs/ton GW)
The above data has been converted to groundwood (GW)
production using the conversion factors above. Thus, to
estimate the raw waste loads that would be generated at a
dissolving pulp mill, the flume RWL characteristics shown
above would be multiplied by 2.75 (i.e. flow would be 8.8
kl/kkg (2.1 kgal/ton)).
161
-------
Information and data were unavailable for log pond
defreezing operations but it is expected that effluent
characteristics would be similiar for both flumes and log
pond defreezing operations.
Log Washing and Chip Washing/Dethawing Operations
In a number of mills, log washing is provided before dry or
wet barking by water showers. The water showers helps to
remove silt which clings to the log during storage (32). In
most installations, the shower is activated by each log
while on the conveyor so that a minimum of water is used.
Table 33 presents data from reference (33) showing the raw
wastes associated with log washing operations but
information is not available which details the type of
mill (s) that the data represents (i.e., groundwood, chemical
pulping).
Table 33
Log Washing Effluents (33)
Flow 0.417 to 1.25 kl/kkg (0.1 to 0.3 kgal/ton)
BODS 0.5 to 4.0 kg/kkg (1.0 to 8.0 Ibs/ton)
TSS 2.5 to 27.5 kg/kkg (5.0 to 55 Ibs/ton)
Color < 50 units
More recent data for log washing operations from surveyed
mills are shown below in Table 34 and the average flow and
BODS loads for the three mills were used as the basis for
the allowance for log washing operations. Since data were
unavailable for chip washing and thawing operations and
because log and chip washing/thawing operations are similar,
the raw .waste characteristics for log washing operations
were also used as representative of chip washing and thawing
operations.
162
-------
Table 34
Log Washing Effluent Characteristics
Flow
Mill kg/kkg GW (kgal/ton GW)
402 2.3
064 1.1
141
Ave. 1.7
Barking Operations
(0.56)
(0.26)
( ~ )
(0.41)
BOD 5
kq/kkq GW fibs/ton GW)
0.30
0.20
0.33
0.28
(0.60)
(0.40)
(0.66)
(0.55)
Depending upon a number of factors at each mill including
the type of wood, size of the logs, and condition of the
logs (i.e., frozen), mills use either wet or dry barking
operations. Dry barking operations are most commonly done
in rotating drums but a number of mills use ring barkers.
Wet barking operations include drum barkers, pocket barkers,
and hydraulic barkers. These operations and the raw waste
characteristics associated with each operation are discussed
below. Figure 37 presents a process diagram for wet barking
operations (342).
Drum Barking
Wood is fed into a rotating cylindrical shell with a
horizontal longitudinal axis. The cylinder or drum is
slotted and equipped with internal staves which knock the
bark from the wood as the drum rotates. The bark falls
through the slots in the drum and is generally removed by
conveyors. In wet barking operations a constant depth of
water is kept in the drum which is a solid vat section with
annular rings to keep the water within the drum. Removal of
the bark is facilitated by the overflow of water at the
section ends. In some cases, this section is part of a
three section system which includes two dry barking drums;
the wet barking drum, in this case, can be put at the head
of the system to facilitate thawing and removal of silt or
at the end of the system to accomplish final barking and
cleansing of the wood. Typical size and capacity for a drum
barker is 12 feet in diameter and 68 feet in length with a
capacity of 7 to 45 cords/hr. The water sprays involved in
wet barking provide 500 to 1,500 gpm at a temperature of 100
to 200°F if used for thawing. Typical loadings of wet
barking effluents are found in Table 35.
163
-------
PROCESS
WATER
1
FIGURE 37
WET BARKING PROCESS DIAGRAM
cr>
LOG
STORAGE
PROCESS
BACK WATER
1
i
LOG
WASHER
i
1 1
1 i
WET DRUM
POCKET OR
HYDRAULIC BARKER
I
i
DEBARKED
LOGS
OFF GASES
Mt
CYCLONE
COARSE
SCREENING
BARK
PRESS
BARK
BOILER
ASH TO LAND
DISPOSAL
f
+
I
DIVERSION
BOX
1
i
EFFLUENT
PRCHDUCT &
RAW MAT!,
PROCESS WATER —
BACK WATER
GASES
BARK, ASH
RESIDUE -1"*--*"*-*
EFFLUENT
-------
TABLE 35
ANALYSIS OF WET DHJM BARKING EFFLUENTS
TSS
mg/i
NON-SET.
SOLIDS
mg/1
% ASH
OF
SS
BOD5
mg/1
COLOR
UNITS
en
en
2017 69 480 20
317 57 21 605 50
2875 80 18 987 50
-------
Spent process water is frequently used in wet drum barkers
and recycling within the barking unit itself is often
practiced. Barkers of this type contribute from 7.5 to 10
kg of BOD5 (15 to 20 Ib) and from 15 to 50 kg (30 to 100 Ib)
of suspended solids per kkg (ton) of wood barked. The bark
and waste water removed with the overflow are generally
thoroughly screened. A common method of bark disposal is to
burn it as fuel in the mill boilers. To do this, it must be
dewatered and then pressed to remove excess moisture. This
pressed bark fuel will provide approximately 9000 Btu/lb of
dry weight. Water discharged from the drums is combined
with pre-wash water from sprays, and primary or coarse
screens are then used to remove large pieces of bark and
wood slivers. The primary screening effluent contains from
2000 to 4000 ppm of combustible suspended solids in addition
to varying forms of ash in the form of silt. The waste
water is then passed through the secondary screening
devices, usually flat-bed vibrating screens. The secondary
screening effluents have suspended solids contents ranging
from 200 to 2500 mg/1 with 10% to 40% of the suspended
solids being ash. Secondary screening effectively removes
most of the large material and 55% to 90% of the residual
suspended solids may pass a 100 mesh screen when fine media
is used. About 30 to 60 minutes of sedimentation will
essentailly remove 70% to 95% of remaining suspended solids,
depending of silt content and efficiency of secondary
screening. The BOD5> of the barker effluent ranges from 60
to 120 mg/1 with the bulk of the BODjj lying either in the
dissolved solids fraction or that fraction passing the 200 -
mesh sieve (7U microns). Table 36 (3U3) presents data on
raw waste characteristics from mills using wet drum barkers
but it should be noted that the type of pulping process is
unknown for these mills.
Pocket Barking
Pocket barkers are stationary machines which grate the bark
from timber by jostling and rotating a confined wood stack
against a chain belt with a system of moving bars with
spikes which rip and tear the attached bark. Loosened bark
falls through the chains and is removed. Wet pocket barking
is facilitated by water sprayed through apertures in the
sides of the pocket. Quantities of water used vary but
typical values are between 330 and 600 gpm for pockets of
2.8 and 5.7 cords/hr., respectively. Also, for wet pocket
barkers, a flume is generally used to catch both the
overflow and the falling bark. The flume carries waste
water and bark to the screening operations. A typical
pocket-barking machine is driven by an electric motor which
requires 40 hp. for barking 6.6 feet long wood and 67 hp.
166
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Table 36
Raw Waste Characteristics (343)
Wet Drum Barking
Mill
AC
CE
EG
GI
IK
KM
MO
OQ
OS
Ave.
Flow
kl/kkg(kgal/ton)
10
9
(2.4)
(2.2)
13 (3.1)
23 (5.5)
(2.6)
(1.0)
(5.0)
(1.0)
(6.7)
11
4
21
4
28
BOD5
kg/kkg/(lbs/ton)
0.6
0.9
6.0
3.0
1.8
1.0
9.5
5.8
10.0
(1.2)
(1.8)
(12.0)
(6.0)
(3.6)
(2.0)
(19.0)
(11.6)
(20.0)
TSS
kg/kkg/(lbs/ton)
3.2
3.8
2.7
15.0
11.4
5.0
(6.4)
(7.6)
(5.4)
(30.0)
(22.8)
(10.0)
13.8(3.3)
4.3 (8.6)
9.0 (18.0)
15.0 (30.0)
17.0 (34.0)
9.1 (18.2)
167
-------
for barking 13.2 feet long wood. Barking residuals lends
themselves to either direct incineration or disposal by
landfill due to their high dry solids content (UO-U5
percent).
Hydraulic Barking
Hydraulic barkers emply high-pressure water jets to blast
the bark off logs which are either conveyed past them or
rotated under a moving jet which transverses the log. There
are two classes of hydraulic barking: 1) machines through
which the logs are fed axially and 2) machines through which
the logs are fed transversely. The volume of water employed
by the high-pressure jets of hydraulic barkers is generally
from 19.0 to 45.U kl (5.0 to 12.0 kgal) per cord of wood
barked depending upon log diameter.
Axial - Feed Machines There are several different types of
axial-feed machines. In one, the jet nozzles are fixed to a
rotating ring through which the logs are fed. In another
type, a nozzle is fixed to each end of a pair of arms
positioned on either side of the path of the logs. The arms
are spun so that the nozzles, which are pointed slightly
inward, direct a cone of high pressure water from each arm
onto the surface of the log. In another method, two or
three nozzles are mounted on horizontal pivots around a
circular arc in the vertical plane and are oscillated up and
down while directing their spray inward against logs fed
either simply or spirally past them. In a variation of this
method, five nozzles are mounted on the face of a ring so
that they point radially inward. The ring is oscillated
through an angle of 80° as the wood is passed through it.
Strips of bark left on large diameter logs are removed by
indexing the logs through a small angle and passing them
through the barker again. Most axial-feed barkers handle
regular wood of small diameter, but some can bark logs up to
60 inches in diameter.
Traversing - Jet Machines In this method, the log is
positioned on the barker and then rotated around its
longitudinal axis while a jet of high-pressure water
traverses its length. Earlier models were of the lathe type
in which the jet was moved relatively slowly along the
length of the log, a single traverse giving complete
coverage of its surface. On these machines, bark removal
started at one end of the log and progressed gradually
towards the other. Conventional models utilize a double-
acting cylinder which carries the jet nozzle rapidly back
and forth over the length of the log so that strips of bark
are consecutively blasted from it as it rotates. Traversing
168
-------
jet machines are commonly built to handle logs up to 72
inches in diameter by 24 feet long and in some cases up to
40 feet long.
Wet Barking Raw Waste Characteristics
Water reguirements are quite stringent for hydraulic
barking; salt water cannot be used due to its corrosive
effects, and fresh water is usually carefully filtered to
remove the silt and other particles which might otherwise
cause excessive wear of barker components. The amount of
water utilized in hydraulic barking varies from 400 to 1600
gpm and from 400 to 1600 hp is needed to deliver this water
at barking pressure which range from 800 to 1600 psi.
Typical capacity is 1500 psi pressure for a flow of 1200 gpm
with yields of 10 cords/hour production. Approximately 1200
hp is required for the pumps alone to provide that flow
rate.
Water discharged from all three types of wet barking is
usually combined with log washing waste water, and coarse
screens are used to remove the large pieces of bark and wood
slivers. The flow then passes to fine screens. Screenings
are removed and mixed with the coarse materials from th6
initial screenings and the mixture is dewatered in a press
prior to burning in a bark boiler. Press water, which is
combined with the fine screen effluent, is relatively minor
in volume. The total waste flow, which amounts to about
19.0 to 26.5 kl (5.0 to 7.0 kgal) a cord, generally carries
from 0.5 to 5.0 kg/kkg (1 to 10 Ib/ton) of BOD5_ and 3.0 to
27.5 kg/kkg (6 to 55 Ib/ton) of suspended solids.
The combined discharge contains bark fines and silt. The
quantity of the latter varies greatly from wet to dry
weather since its presence is due mainly to soil adhering to
the logs. The added bark fines and silt are removed by
primary treatment and have negligible impacts on the final
effluent qualities.
The fine screen effluents following hydraulic barkers (32)
(33) (35) of eight wood handling operations are analyzed in
Table 37 which indicates a total suspended solids content
ranging from 520 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 the the
contact of the water with the bark is short and no grinding
action on the wood takes place. Also, the water employed is
all fresh process water. Table 38 shows recent data on
169
-------
TftRT.K 37
ANALYSIS OF HYDRAULIC BARKING EFFLUENTS*
Mill
Code
AB
CD
EF
GH
U
KL
MN
CP
TSS
ng/1
2362
889
1391
550
521
2017
2000
600
NON-SET.
SOLIDS
ng/1
141
101
180
66
53
69
<200
41
% ASH
OF
SS
27
14
17
11
13
21
19
10
BOD5
mg/1
85
101
64
99
121
56
97
250
COLOR
UNITS
<50
<50
<50
<50
<50
<50
35
* Flow data not available
-------
mBLE 38
HYDRAULIC BARKER EFFLUENTS*
Mill
AA
BB
CC
DD
EE
FF
FF
Flow
kl/day(kgal/day)
816(900)
816(900)
1179 (1300)
1633(1800)
363(400)
1270 (1400)
1270(1400)
BODs
118
71
58
72
114
34**
29
TSS
110
128
116
135
183
234**
64
Production
cords/day
940
385
910
1130
330
NA
MA
* Data represents clarifier effluents treating hydraulic barker waste waters.
** Clarifier influent.
171
-------
effluent characteristics of clarifier effluents treating
hydraulic barker waste waters for seven mills.
Such low BOD5_ values are not the case with drum and pocket
grinding which involve attrition in contact with water over
an appreciable period of time and frequently use spent
pulping process waters already high in BOD5 and color (35)
(36). The suspended solids content is not appreciably
different. The wet drum barking effluents of three
operations are analyzed in Table 35. Effluent volumes were
unavailable.
Table 39 presents raw waste data for surveyed mills using
either hydraulic or drum debarking operations. The data in
Table 39 has been converted to groundwood pulp production
using the factors discussed previously.
BOD5 values of barking effluents are also affected by the
species of wood barked and the season in which the wood was
cut due to variables in wood juices and water extractables.
Because these waste waters are such a small fraction of the
total raw waste load from a mill, the impacts on raw waste
load of the variables associated with the species of wood
and the season in which the wood was cut are generally
immeasurable.
Table 40 summarizes the raw waste characteristics for each
of the three basic types of woodyard operations. The data
is per the type of production shown and was used as the
basis for the woodyard effluent limitations as shown in
Section IX.
PULPING PROCESSES
GROUNDWOQD SUBCATEGORIES
As discussed in section III, the types of groundwood and
chemical-mechanical pulps produced by grinding wood billets
or chips are as follows;
1. Stone groundwood
2. Refiner groundwood
3. Chemi-groundwood
4. Cold soda
5. Thermo-mechanical
Mechanical power is the essential force in the production of
all five although the latter three processes involve a pre-
softening step which, in the case of chemi-groundwood and
172
-------
Table 39
Raw Waste Characteristics
Debarking Operations
Mill
Flow
kl/kkg GW (kgal/ton GW)
Hydraulic Debarkers
184
Oil
402
511
060
073
070
AA
BB
OC
DD
EE
Ave.
401
063
067
Ave.
Total
54.6
46.7
5.4
17.5
16.7
10.8
6.3
3.8
8.8
5.4
5.8
4.6
15.4
Drum Debarkers
12.1
3.8
26.3
14.2
Ave. 15.4
(13.1)
(11.2)
( 1.3)
( 4.2)
( 4.0)
( 2.6)
( 1.5)
( 0.9)
( 2.1)
( 1.3)
( 1.4)
( 1.1)
( 3.7)
( 2.9)
( 0.9)
( 6.3)
( 3.4)
( 3.7)
BCD 5
kg/kkg GW (Ibs/ton GW)
3.0
1.1
0.3
3.3
11.8
1.2
3.0
0.5
0.7
0.4
0.5
0.6
2.2
1.3
4.3
2.2
2.6
2.3
(5.9)
(2.1)
(0.6)
(6.6)
(23.5)
(2.4)
(6.0)
(1.0)
(1.4)
(0.7)
(1.0)
(1.2)
(4.4)
(2.5)
(8.5)
(4.3)
(5.1)
(4.5)
173
-------
Table 40
Sutttary of WDodyard Operation's
Raw Waste Characteristics
Type of Pulping
Woodyard
Operation
Groundwood
Papergrade Kraft,
Soda, Sulfite
Dissolving
Pulp
Debarking
Flow (1)
BODs (2)
15.4
21.3
(3.7)
(5.1)
3.7 (7.4)
5.1 (10.2)
5.1
7.0
(10.2)
(14.0)
Log/Chip Wash
Flow (1)
BODs (2)
1.7
2.5
(0.4)
(0.6)
0.4
0.6
(0.8)
(1.2)
0.6
0.9
( 1.1)
( 1.7)
Flume/Pond
Flow (1)
BODs (2)
3.3
3.3
(0.8)
(0.8)
0.8
0.8
(1.6)
(1.6)
1.1
1.1
( 2.2)
( 2.2)
(1) Flow in kl/fekg (kgal/ton)
(2) BODS in kg/kkg/ (Ibs/ton)
174
-------
cold soda, includes the use of chemicals. This reduces the
power requirement and produces pulps with somewhat different
characteristics (2) (5) .
Effluents produced by all of these pulping methods contain
suspended solids and dissolved organic matter, both of which
contribute to the BOD5 (5) (37) . In addition, chemi-
groundwood and cold soda process waters contribute
electrolytes which contain some ions in the form of residual
and spent chemicals. Most of these are combined with
organic matter.
Raw waste characteristics of a groundwood mill are
summarized in Figure 38 which is presented as an example of
a groundwood mill with the effluent characteristics shown in
order to demonstrate the relative contributions of the
pulping and papermaking operations to the total raw waste
load. Effluent volume from the pulp mill can be expected to
range between 8.3 and 16.7 kl/kkg (2.0 and U.O kgal/ton).
For example. Mill 13 had an effluent volume from the pulp
mill of 13.6 kl/kkg (3.26 kgal/ton). In addition, mill 017
is a groundwood mill which manufactures market pulp only and
has a raw waste flow of 12.5 kl/kkg (3.0 kgal/ton).
Differences in discharge volume are generally due to
equipment variations and the species of wood pulped, with
more fresh water usually required for resinous wood.
Clarified white water from papermaking operations is
frequently a partial source of process water used in the
groundwood pulping and contains additional electrolytes in
the form of papermaking additives (2) .
The suspended solids present in groundwood effluents consist
primarily of fiber fines, ray cells, and hydrated wood dust.
They are over 90 percent combustible, and while they are
mostly settleable, they will not thicken to a substantial
degree and seldom produce a sludge of over two percent
solids (5) . This is due to hydration produced by grinding
and the small particle size of these solids. Data gathered
during an earlier study (5) shows a range of total suspended
solids in groundwood pulping effluents as follows:
175
-------
FIGURE 38
EFFLUENT CHARACTERISTICS: GROUNDWOOD MILL
PROCESS
WATER
PULP MILL
3,000 GAL/TON
36 LB TSS/TON
PAPER MILL
21,000 GAL/TON
92 LB TSS/TON
RAW
WASTE
24,000 GAL/TON
38 LB BODg/TOr
128 LB TSS/TON
6.1 pH
176
-------
Total Suspended Solids Range
Type of Pulp kq/kkq (lb/ton|
Stone 5.5 - 10.5 (11-21)
Refiner 15 - 29.5 (30-59)
Chemi-groundwood 7.5 - 16 (15-32)
Cold Soda 12 - 18.5 (24-37)
There are no data from surveyed mills to verify the above
TSS ranges, since very few mills measure pulp mill wastes
alone. Surveyed mill data on total raw waste TSS, however,
show no discernible relationship between TSS and the types
of groundwood pulping processes. The raw load TSS data show
a range of 21 kg/kkg (42 Ib/ton) to 80.5 kg/kkg (161
Ib/ton), with chemi-mechanical Mills 001 and 012 at the low
and high ends of this range, i.e., 23.3 kg/kkg (46.6 Ib/ton)
and 80.5 kg/kkg (161 Ib/ton) respectively. Mills 004 and
002 on the other hand, fall in the middle of this range with
TSS values of 29,1 kg/kkg (58.1 Ib/ton) and 60.5 kg/kkg (121
Ib/ton), respectively. These mills are refiner and stone
groundwood mills, respectively.
Dissolved organic materials present in groundwood waste
waters consist of wood sugars and cellulose degradation
products as well as resinous substances. In effluents free
of appreciable fiber the dissolved organics account for
about three-quarters of the BOD5. The BODj> discharge of the
various groundwood pulping processes range7 according to the
above study (5) , as follows:
BOD5
Type of Pulp kg/kkg(Ib/ton)
Stone 4 - 9.5 (8-19)
Refiner 9-16 (18-32)
Chemi-groundwood 34.5 - 40.5 (69-81)
Cold Soda 36.5 - 50.5 (73-101)
The higher values observed for pulps whose manufacture
involves the use of conditioning chemicals are due to the
solubilizing and peptizing effects on the organics present
177
-------
in the wood. Data from surveyed mills tend to support this
conclusion through comparison of Stream 9 values. Mills 1
and 12, which add chemicals and are in the chemi-mechanical
subcategory, have raw waste BODJ51 s which are significantly
higher than those presented above and average about 95.0
kg/kkg (190 Ibs/ton). Mills not employing chemicals or a
"pre-softening" step, on the other hand, generally have a
much lower BOD5 with a typical value of about 17.5 kg/kkg
(35 Ib/ton). It should be pointed out that the data from
surveyed mills did not support the above differences in BOD5_
raw waste loads for mills using stone groundwood and mills
using refiner groundwood.
In cold soda pulping, 18 to 45 kg/kkg (40 to 80 Ibs/ton) of
sodium are added. Some of the sodium ion remains adsorbed
on or chemically bound to the pulp; another portion appears
in the effluent chemically bonded to organics such as resins
and lignins; and a third is a residual of unreacted chemical
also present in the effluent. The chemi-groundwood process
which employs sodium sulfite and caustic soda contributes
sulfur as well, in the range of 2.5 to 5 kg/kkg (5 to 10
Ibs/ton).
The production of market pulp at groundwood mills
demonstrates that most of the effluent flow and about one
third to one half of the BOD5_ in the effluent is associated
with the production of paper. Mill 017 produces groundwood
market pulp and has a raw waste flow of 12.5 kl/kkg (3.0
kgal/ton) and a BOD5_ of 9.75 kg/kkg (19.5 Ibs/ton). This is
substantially less than the raw waste loads for groundwood
mills producing papers which range from 52.9 kl/kkg (12.7
kgal/ton) to 115 kl/kkg (27.6 kgal/ton) for flow and from
9.95 kg/kkg (19.9 Ibs/ton) to 21.45 kg/kkg (42.9 Ibs/ton)
for BODj> for surveyed mills.
The pH of all groundwood effluents, except cold soda, is in
the neutral range, somewhat on the alkaline side.
The color of groundwood effluents from most of the woods
pulped is generally under 100 mg/1.
As discussed in Section III, groundwood pulp is generally
bleached or brightened with hydrogen or sodium peroxide,
sodium or zinc hydrosulfite, or sodium sulfite. In
practice, the pH is usually adjusted to between 4.5 and 7.0
depending upon the bleaching agent and sometimes complexing
chemicals are added to overcome the effect of heavy metals
that may be present, such as iron and manganese. Buffers
and catalytic agents in trace quantities are also sometimes
used. Since groundwood can be bleached at high consistency.
178
-------
it is frequently accomplished in stock chests. Bleaching
agents are not washed from the pulp and thus, the residues
of bleaching appear in the white water of the paper machine
system. As shown in Table 29 in Section IV, data from
surveyed mills do not demonstrate any clear relationship
between degree of bleaching, as measured by pulp brightness,
and resulting raw waste flow or BODf>. It is quite apparent
that any impacts of the degree of bleaching upon raw waste
load are taken into account through the subcategorization
into two subcategories: groundwood fine papers and
groundwood CMN papers. As shown in the table the mills
producing fine papers bleach to brightness levels in the 70
to 80 range while mills producing CMN produce papers in the
55 to 60 range.
The higher concentration of zinc in groundwood effluents are
undoubtedly attributable to the use of zinc hydrosulfite.
Most mills are now abandoning the use of this chemical in
favor of alternate bleaching agents such as sodium
hydrosulfite.
Development of Subcategory Raw Waste Loads
The development of the raw waste loads (RWL) for each of the
groundwood subcategories is discussed below. The resultant
raw waste loads were used in developing the effluent
limitations for each subcategory and in determining the
costs presented in Section VIII.
GW: Chemi-Mechanical Subcategory
Two mills are included in the chemi-mechanical subcategory.
These mills use similar pulping processes to manufacture
distinctly different products, fine papers and molded pulp
products. Both mills purchase in varying amounts pulp and
waste paper as additional sources of fiber. The raw waste
BOD5_ characteristics and flow volume for the mills is very
similar; as discussed in Section IV, this indicates that the
most significant effect upon the RWL is the pulping process.
Mill 001 has a BOD5; RWL of 48.5 kg/kkg (97.0 Ibs/ton)
whereas mill 012 has a BOD5 RWL of 53.0 kg/kkg (106
Ibs/ton). Similarly, effluent flow values are 84.6 kl/kkg
(20.3 kgal/ton) and 81.3 kl/kkg (19.5 kgal/ton),
respectively. Mill 001 uses 5031 chemi-mechanical pulp and
50% purchased pulp; while Mill 012 uses 45% chemi-mechanical
pulp, 45% purchased pulp, and 10% waste paper. Using 10.75
kg/kkg (21.5 Ibs/ton) of BOD5_ attributable to paper made
from purchased pulp and 12.5 kg/kkg (25.0 Ibs/ton) of BOD5_
attributable to paper made from waste paper, the
contribution of BOD5> from the production of 100% chemi-
179
-------
oo
o
TABIE <*1
RAW WASTE LOAD - GW-CHEMI-MECHANICAL SUBCATEGORY
Actual
Mill
01
12
Manufacture (%) *
GW PP WP
50 50 0
45 45 10
Average
Production
kkg/day (tons/day)
97 (107)
326
(359)
Flow
kl/kkg (kgal/ton)
84.6 (20.3)
81.
83.
3 (19
0 (19
.5)
.9)
BOD5
kg/kkg (Ibs/ton)
48.5 ( 97.0)
53.
50.
0 (106.0)
5 (101.0)
mg/1
573
652
609
TSS
kg/kkg (Ibs/ton)
23.3 ( 46.6)
80.5
52.0
(161.0)
(104.0)
Calculated
Mill
01
12
* GW:
PP:
WP:
Production
kkg/day (tons/day)
97 (107)
Average
Groundwood Pulp
Purchased Pulp
Waste Paper
326
(359)
Flow
kl/kkg (kgal/ton)
121 (29.0)
104
112
(25
(27
.0)
.0)
BODs
kg/kkg (Ibs/ton)
86.5 (173)
105
96
(209)
(191)
mg/1
713
1000
848
TSS**
kg/kkg (Ibs/ton)
23.3 ( 46.6)
80.5
52.0
(161.0)
1104.0)
** Actual TSS Values
mg/1
275
990
627
mg/1
275
990
462
-------
During an on-site plant survey by an EPA representative to a
non-integrated thermo-mechanical mill in Sweden, the mill's
RWL BOD5_ was reported to be 21.25 kg/kkg (42.5 Ibs/ton) with
an effluent flow of 17.1 to 27.5 kl/kkg (4.1 to 6.6
kgal/ton). The effluent flow corresponds relatively well
with the flow data for the pulping operations at mills 013
and 017 which were presented previously.
The thermo-mechanical mill, mill 041, which began operations
in the Fall of 1975 has reported that the effluent treatment
facilities have been designed for a flow of approximately
41.7 kl/kkg (10.0 kgal/ton) with hopes of actually operating
at 20.8 kl/kkg (5.0 kgal/ton) (39). However, recent data
from the mill indicate flows of 88.0 kl/kkg (21.1 kgal/ton).
Table 42 presents the raw waste load data for mills 028 and
041. Mill 028 produces construction type papers and
achieves a BOD5 raw waste load of approximately half that
being discharged by mill 041. However, the flow raw waste
flows are about the same for the two mills. Since there is
not an extensive amount of data available, the subcategory
raw waste loads were based upon mill 041. The
groundwood:thermo-mechanical raw waste load which were used
as the basis for the effluent limitations are therefore
shown below:
Flow: 88.0 kl/kkg (21.1 kgal/ton)
BOD5: 39.2 kg/kkg (78.4 Ibs/ton)
TSS: 39.9 kg/kkg (79.8 Ibs/ton)
In mechanical pulping, the yield gives an excellent
indication of the effluent BOD5_ characteristics. Generally,
the higher the yield, the less the BODJ5 PWL will be. Table
43 shows the yields and BOD5 RWL for chemi-mechanical,
thermo-mechanical, and groundwood processes, and as shown
the yield is related to the inclusion of the pre-softening
step.
181
-------
mechanical pulp at each mill was calculated similar to the
bleached kraft subcategories discussed later. The estimated
BOD5 raw waste load for mill 001 and mill 012 which
represents on-site production of exclusively chemi-
mechanical pulp into paper products of 86.25 kg/kkg (172.5
Ibs/ton) and 104.25 kg/kkg (208.5 Ibs/ton), respectively.
Similarly, flow due to paper made from the chemi-mechanical
process was calculated based upon 62.6 kl/kkg (15.0
kgal/ton) for purchased pulp and 41.7 kl/kkg (10.0 kgal/ton)
for waste paper. The representative flows for mill 001 and
mill 012 were 121 kl/kkg (29.0 kgal/ton) and 10U kl/kkg
(25.0 kgal/ton) , respectively. As discussed previously, raw
waste TSS values do not generally correlate between mills
because of the differences in internal measures used to
control the loss of fiber. The RWL for these mills are
summarized in Table HI and are shown below:
Flow: 112 kl/kkg (27.0 kgal/ton)
BODS: 96.0 kg/kkg (191 Ibs/ton)
TSS: 52.0 kg/kkg (10U Ibs/ton)
GW: Thermo-Mechanical Subcategory
The thermo-mechanical process is relatively new in this
country, and it has been reported that at least 15 mills
were using the thermo-mechanical process by the end of 1975
with approximately 2,041 kkg (2250 tons) per day of
production capacity. (37) (306). The majority of the mills
presently operating thermo-mechanical systems are operating
in conjunction with some other pulping process such as
bleached kraft, sulfite, or stone groundwood. Because of
the mixture of pulping operations at these mills, waste
water data representing exclusively that discharged by the
thermo-mechanical process were only available from two
mills: mills 028 and 041.
Thermo-mechanical pulping has been practiced in the Swedish
pulp and paper industry since 1967. Data received from IVL
(Swedish Pollution Control Company), Stockholm, Sweden,
showed that BOD7_ RWL for thermo-mechanical pulping was 16-18
kg/kkg (32-36 Ib/ton) and an additional 15 kg/kkg (30
Ibs/ton) if peroxide bleaching was practiced. IVL reports a
conversion factor for BOD7_ to BOD5_ of 0.85. The above data
were based upon sampling of effluents from two thermo-
mechanical mills in Sweden. Thus, the maximum BOD5 that
would be expected from mills practicing thermo-mechanical
pulping and peroxide bleaching is 28.0 kg/kkg (56.0
Ibs/ton).
182
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TABLE 42
RAW WASTE BOD5
GW: THERMO-MECHANICAL MILLS
Flow BOD5. TSS
Mill k1/kkg(kga1/ton) kg/kkg(lbs/ton) kg/kkg(1bs/ton)
028 86.7(20.8) 19.8(39.6) 49.2(98.3)
041 88.0(21.1) 39.2(28.4) 39.9(79.3)
183
-------
Table 43
BOD5 vs Groundwood Yield
Pulping Process
Chemi-Mechanical
Thermo-Mechanical
Groundwood
Pre-
Softening
Step
20 mins.
2-7 mins.
None
Chemical
Addition
Yes
Sometimes
No
Yield BOD5.
% kg/kkg (Ibs/ton)
80-95
90-97
90-98
95.5
39.0
17.5
(191)
(78)
(35)
GW: Fine Papers Subcategory
Table 44 is a summary of the data from which the groundwood
fine papers subcategory RWL were developed. As shown in
Table 44, many of these mills purchase pulp and/or waste
paper as a supplementary source of fiber. Also, the
papermaking additives content of the final products ranges
from 10 to 35% by weight. Since groundwood mills producing
fine papers generally purchase supplementary fiber (market
pulp or waste paper) and since no significant relationships
exist for the mills in Table 44 between RWL and the amount
of fiber purchased, the subcategory RWL was developed by
averaging the flow, BOD5_, and TSS data shown in the table.
Mill 021, as noted in the table, uses the thermo-mechanical
process for 10% of their total production and since the flow
value of 51.7 kl/kkg (12.4 kgal/ton) is significantly lower
than the other mills flows, the RWL for mill 021 was not
included in the calculation of the subcategory averages.
The subcategory RWL would, however, fce lower if mill 021
were included. The subcategory raw waste loads are
therefore the following:
Flow: 91.3 kl/kkg (21.9 kgal/ton)
BODS: 16.7 kg/kkg (33.3 Ibs/ton)
TSS: 52.5 kg/kkg (105 Ibs/ton)
GW: CMN Papers Subcategory
Table 45 shows manufacturing information and effluent
characteristics for groundwood mills producing coarse (C)
papers, molded pulp products (M) , and/or news (N) papers.
Also, shown is mill 017 which is a small mill producing 29
kkg (32 tons) per day of market (mkt) groundwood pulp.
As shown in Table 45, mills in the GW:CMN subcategory
purchase additional fiber to Supplement the groundwood pulp
184
-------
TABLE 44
RAW WASTE LOAD - GW-FINE PAPERS SUBCATBGOKf
oo
en
Manufacture (%)
Production
Flow
BODS
TSS
Mill
03
19
05
20
02
13
21**
GW
30
30
30
33
55
55
40*
PP
40
25
55
33
30
30
25
WP
10
35
5
0
0
0
15
C&F
20
35
10
33
15
15
20
kkg/day (tons/day) kl/kkg (kgal/ton)
492
453
498
537
193
457
517
(542)
(499)
(549)
(592)
(213)
(504)
(570)
Average
106.3
78.8
97.6
83.0
99.7
83.0
51.7
91.3
(25.5)
(18.9)
(23.4)
(19.9)
(23.9)
(19.9)
(12.4)
(21.9)
kg/kkg(lbs/ton)
16.3
20.9
18.0
12.8
18.6
13.5
15.2
16.7
(32.5)
(41.8)
(35.9)
(25.6)
(37.1)
(27.0)
(30.4)
(33.3)
mg/L.
153
265
183
154
187
163
294
182
kg/kkg (Ibs/ton)
66.0
42.5
51.5
41.4
60.5
49.0
32.8
52.5
(132)
(85.0)
(103 )N
(82.8)
(121)
( 98)N
(65.5)
(105)
mg/L
621
539
526
499
610
590
633
575
*10% of total production is reported as thermo-inechanical
**Mot included in the average (see text)
-------
TABLE 45
RAW WASTE LOAD - GW-CMN PAPERS SUBCATEGORY
Manufacture (%) Production
Flew
00
Mill
09
10
08
14
04
16
15
17*
GW
80
80
70
75
55
65
90
100
PP
20
20
30
25
20
30
0
0
WP
0
0
0
0
25
5
10
0
Product
N
N
N
N,C
C
M
M
Mkt
kkg/day (tons/day)
342
904
374
96
72
69
113
29
(377)
(997)
(412)
(106)
( 79)
( 76)
(125)
( 32)
Average
kl/kkg (kgal/ton)
52.9
112.6
115.1
107.6
113.0
86.3
107.6
12.5
99.2
(12.7)
(27.0)
(27.6)
(25.8)
(27.1)
(20.7)
(25.8) '
( 3.0)
(23.8)
kg/kkg(lbs/ton)
19.6
21.4
20.3
12.0
9.9
19.1
19.5
9.7
17.4
(39.2)
(42.9)
(40.7)
(24.0)
(19.9)
(38.2)
(39.0)
(19.5)
(34.8)
mg/1
370
191
177
112
88
221
181
779
175
kg/kkg ( Ibs/tonL
21.0
-
68.0
63.0
33.0
62.0
78.0
12.5
48.5
(42.0)
( - )
(136)N
(126)N
(66.0)
(124)
(156)
(25.0)
(97.0)
mg/1
397
-
591
586
292
718
725
999
489
*Not included in subcategory average (see text)
Code: N - Newspaper
C - Coarse Paper
M - Molded Pulp Products
Mkt - Market Pulp
-------
produced on-site which is similar to groundwood mills
producing fine papers. However, the amount of purchased
additional fiber is significantly different between mills
producing CMN papers and mills producing fine papers. As
shown in Tables 44 and 45, respectively, mills in the GW:
fine papers subcategory manufacture 30-5531 of their total
product by on-site groundwood pulping whereas mills in the
GW:CMN papers subcategory generally manufacture 65 to 80%
on-site. The amount of market pulp purchased to supplement
the groundwood pulp produced on-site is generally a function
of the type of paper produced; i.e. manufacture of
newspapers requires a blend of 65-80% groundwood pulp (short
fibers) and 20-35X chemical pulp (long-fibers) .
The GW: CMN papers subcategory PWL was determined by
averaging the RWL data presented in Table 45. Non-standard
TSS results for Mills 008 and 014 appear high, and since
they cannot be included in the averaging, the two highest
values. Mills 015 and 016, were averaged to obtain the
subcategory raw waste load TSS. Data for Mill 017 were not
included as the mill produces market pulp and the data
showed effluent flows of 12.5 kl/kkg (3.0 kgal/ton) which
were significantly below all other mills in the subcategory.
The subcategory raw waste loads are summarized in Table 45
and are shown below:
Flow:
BODS:
TSS:
99.2 kl/kkg (23.8 kgal/ton)
17.4 kg/kkg (34.8 Ibs/ton)
48.5 kg/kkg (97.0 Ibs/ton)
Zinc Raw Waste Loads
Groundwood mills using zinc hydrosulfite in the
manufacturing process discharge significantly higher zinc
levels than those mills using another bleaching agent or
those mills that do not bleach their pulps. Data were
available from two mills which use zinc hydrosulfite.
Mill 008 produces approximately 263 kkg (290 tons) per day
of bleached groundwood pulp and purchases approximately 109
kkg (120 tons) per day of bleached kraft pulp, which is used
to manufacture 354 kkg (390 tons) per day of newsprint
(approximately 49 percent is standard newsprint and 51
percent is printing grade paper).
The zinc hydrosulfite used in bleaching is manufactured on
site with 0.907 kkg (1.0 tons) per day of zinc dust utilized
in this process. The brightness achieved after bleaching
with the zinc hydrosulfite is 63 to 64.
187
-------
Mill 141 is a bleached kraft mill which produces an average
of 635 kkg (700 tons) per day of bleach kraft pulp and 272
kkg (300 tons) per day of groundwood pulp. The groundwood
pulp is bleached, when required, to a brightness of 60 to
62. The mill produces approximately 698 kkg (770 tons) per
day of paper products consisting of tissue, towels, and
kraft specialty. It also produces between 290 to 317 kkg
(320 and 350 tons) per day of market pulp. Zinc RWL data
for the two mills are presented in Table 46.
SULFITE SUBCATEGORIES
Mills using sulfite pulping processes were subcategorized
into the papergrade sulfite (Blow Pit Wash), papergrade
sulfite (Drum Wash), and the dissolving sulfite pulp
subcategories. Within the papergrade sulfite subcategories,
allowances have been established for woodyard operations,
type of cooking liquor, the use of surface or barometric
condensers, and the use of continuous digesters. Within the
dissolving sulfite pulp subcategory, allowances were
established for woodyard operations and four different
grades of pulp. The raw waste characteristics are discussed
below.
Papergrade sulfite Subcategories
Sulfite pulp mills which employ spent sulfite recovery
discharge between 63.0 and 125 kl (15.0 and 30.0 kgal) of
effluent per kkg (ton) of pulp. This volume approaches 209
kl (50.0 kgal) per kkg (ton) of pulp in some cases (2) (5).
(It should be noted that the survey data discussed below
represents the total waste stream.) The major pollutional
characteristics of this effluent are BOD5_, suspended solids,
color, and acidity.
Typical data given in the literature on the individual waste
streams emanating from the pulping and bleaching process are
shown in Table 47 (41) (42) (44). Overall losses amount to
about 300 kg (600 Ibs) of total solids, 22.5 kg (45 Ibs) of
suspended solids, and close to 150 kg (300 Ibs) of BOD5_ per
kkg (ton) of pulp produced. The pH value is in the range of
2.5 to 3.2. Solubles present consist of lignosulfonates,
lower fatty acids, alcohols, ketones, and pentose and hexose
sugars (43) as well as a number of miscellaneous complex
compounds such as cymene (30). The lignin fraction is
largely responsible for the color of the effluent, the
degree of which depends upon the efficiency of the liquor
separation and recovery system as well as the base employed
and the wood species pulped (44).
188
-------
TABLE 46
ZINC RAW WASTE LOADS
GRDUNDWOOD MILLS
Flow cms(ingd)
Min.
Ave.
Max.
Production kg(tons)/day 402(443)
Mill
008 a
0.38(8.6)
0.44(10.0)
0.48(11.0)
Mill
0082
0.37(8.4)
0.41(9.3)
0.45(10.2)
Mill
1413
1.0(23.2)
1.4(32.4)
1.7(37.7)
366(403)
256(282)
pH
Min.
Ave.
Max.
Zinc (mg/L)
Min. Day
Max. Day
Ave. Day
Max. 30 Day
Zinc kg/kkg(lbs/ton)
Max. Day
Max. 30 days
5.3
5.9
6.5
2.2
13.7
5.9
8.8
1.3(2.6)
0.9(1.7)
5.5
5.9
6.2
1.3
15.5
5.7
7.8
1.5(3.0)
0.8(1.5)
8.5
9.5
10.7
0.05
1.3
0.4
-
0.6(1
0.2(0
.25)
.38)
5/1/75 to 4/30/76
1/1/75 to 4/30/75
4/1/75 to 3/31/76
Includes groundwood production only
189
-------
Table 47
TYPICAL EFFLUENT LOADINGS FROM INDIVIDUAL
PROCESSES IN A SULFITE PULP HILL
Process Source
Blow Tank
Condensates
Liquor Losses
Screening
Washing & Thickening
Acid Plant Wastes
Boiler Blow Down
Total
Bleaching
Volume
1/kkg
(sal/ton)
7,928
(1,900)
4,590
(1,100)
31,298
(7,500)
25,038
(6,000)
31,298
(7,500)
1,251
(300)
417
(100)
101,823
(24,400)
50,077
(12,000)
Total
Solids
kg/kkg
(Ib/ton)
123.5
(247)
23.5
(47)
52.5
(105)
13.5
(27)
65.5
(131)
5
(10)
11
(22)
294.5
(589)
100
(200)
Suspended
Solids
kg/kkg
(Ib/ton)
0.5
(1.0)
0.05
(0.1)
10.5
(21.0)
4.0
(8.0)
4.0
(8.0)
2.5
(5.0)
1.0
(2.0)
22.5
(45.1)
7.5
(15.0)
BODc
kg/kkg
(Ib/ton)
:,8
(IK)
33
(66)
26.5
(53)
A
(8)
9
(18)
Neg.
Neg.
130.5
(261)
15
(30)
PH
Ranee
2.2-2.9
2.3-3.1
2.2-2.6
5.4-5.7
2.4-3.9
1.2
2.5-3.2
5.0-5.8
-------
As discussed in Section III, the most common method for
bleaching paper grades of sulfite pulp is the three stage
chlorine-alkaline extraction-hypochlorite (CEH) sequence
(8); in recent years, some sulfite mills have used a stage
of chlorine dioxide. Generally, the chemical requirements
of the CEH sequence range from two to six percent of chlo-
rine, 1.0 percent of caustic soda, and from 0.5 to 0.9
percent calcium hypochlorite for bleaching most paper grade
sulfite pulps (2) . Some mills produce a bleached pulp with
a single chlorine or hypochlorite treatment. Others produce
a variety of specialty grades by adjusting the number of
sequences and degrees of chemical treatment in accordance
with the type of pulp desired (91). As many as six stages
are employed for high grade pulps. The bleached pulp is
sometimes treated with sulfur dioxide to remove heavy metals
and retard reversion.
A three stage bleaching operation which does not recycle
discharges about 50.1 kl/kkg (12.0 kgal/ton) of waste water.
Recycling the hypochlorite stage effluent as wash water in
the caustic extraction step can reduce this quantity to
below 41.7 kl/kkg (10.0 kgal/ton). Single stage bleaching
produces about 16.7 kl/kkg (4.0 kgal/ton) of effluent while
125 to 250 kl/kkg (30.0 to 60.0 kgal/ton) is discharged from
bleach plants producing specialty pulps.
The total solids content of the combined effluent of a three
stage bleaching operation ranges from 100 to 125 kg/kkg (200
to 250 Ib/ton) of product and the total suspended solids
from 7.5 to 15 kg/kkg (15 to 30 Ib/ton). The latter are
largely fiber fines which have passed through washer wires.
The BODJ5 ranges from 5 to 30 kg/kkg (10 to 60 Ib/ton) (4)
and color from 10 to 20 kg/kkg (20 to 40 Ib/ton) (77). The
pH is on the acid side generally ranging from 2.5 to 3.5.
The major electrolytes present in these waste waters are the
chlorides of sodium and calcium which amount to about 20 to
25 kg/kkg (40 to 50 Ib/ton).
Effluents from one stage bleacheries contain from 50 to 87.5
kg/kkg (100 to 175 Ib/ton) of total solids and 2.5 to 5
kg/kkg ( 5 to 10 Ib/ton) of total suspended solids. The
BOD5 ranges between 3.5 and 5 kg/kkg (7 and 10 Ib/ton) and
color from 7.5 to 10 kg/kkg (15 to 20 Ib/ton) (90).
Wastes from the on-site manufacture of bleaching chemicals,
such as calcium hypochlorite, are described in the ensuing
section on kraft bleaching.
191
-------
Figure 39 is presented to show the basic contributing waste
streams for a papergrade sulfite mill with the effluent
characteristics shown.
Development of Subcategory Raw Waste Loads
The development of the raw waste loads (RWL) for the
papergrade sulfite subcategories is discussed below. The
resultant raw waste loads were used in developing the
effluent limitations for each subcategory and in determining
the costs presented in Section VIII. As discussed in
Section III, mill visits were made to 18 of the 24 mills in
these subcategories for the purpose of gathering information
and data concerning manufacturing operations and effluent
characteristics. In addition, information and data on every
papergrade sulfite mill was available from Reference 29.
Beyond that contained within the published report (29) , the
raw data sheets were available to support the information
and data summarized in the report. Thus, the subcategory
RWL's were based upon the information and data accumulated
from the plant surveys and upon the supporting information
and data from Reference 29.
Tables 48 and 49 shows information and data for each mill in
the papergrade sulfite subcategories (also the dissolving
sulfite subcategory which will be discussed later) and was
derived from survey data and from the information and data
included in Reference 29 and the supporting raw data sheets.
Table 49 presents information for each sulfite mill
pertaining to the mill location, age, mean minimum and mean
maximum monthly ambient air temperatures for each mill, and
the type of external treatment system which is already
inplace or planned. Mentioned above, most mills use SSL
recovery systems or are presently installing these systems.
As shown in Table 48, 21 of the 24 mills presently have SSL
recovery systems and thereby, as discussed in Sections IV,
VII, and VIII is considered as part of BPCTCA which includes
internal controls commonly practiced by the industry. The
symbols used in Table 48 in the columns entitled "Products"
and "Other Pulping Processes" can be interpreted as follows:
F: fine papers, N: Newspapers, T: Tissue papers, P: Market
pulp, C: Coarse papers, B: paperboard, GW: groundwood, NSSC:
Neutral Sulfite Semi-chemical, BK: bleached kraft, and WP:
waste paperboard. In addition, the column entitled
"Woodyard-Water Use" indicates the use of wet barking
procedures at the mills. Also, the column entitled "Type
Condenser" shows if mills are using barometric (B), surface
(S) or vapor recompression (V) type condensers in their
waste liquor recovery systems. The column entitled "pH to
192
-------
FIGURE 39
EFFLUENT CHARACTERISTICS: SULFITE MILL
PROCESS
WATER
PULP MILL
RECOVERY UNIT
BLEACH PLANT
35,000 GAL/TON
180 LB BODg/TON
50 LB TSS/TON
PAPER MILL
15,000 GAL/TON
10 LB BODg/TON
110 LB TSS/TON
V
RAW
WASTE
50,000 GAL/TON
190 LB BOD5/TOf
160 LB TSS/TON
193
-------
Table 48
Mill Characteristics and Raw Waste Loads
Sulfite Mills
Sulfite Total Other Woodyard Pulp Washing Type Cooking Type SSL pH
Production Production Major Pulping Water Blow Vacuum Bleaching Type Wood Liquor Cooking Yield Recovery to
Mill kkg/day (tons/day) Products Processes %Chips Use Pit Drum Sequence Condenser %SW Base Liquor % % Eva
Dissolving Sulfite
511
512
050
401
402
403
544(600)
579(638)
435(480)
408(450)
449(495)
440(485)
544(600)
579(638)
435(480)
408(450)
449(495)
440(485)
Viscose
Cello-
phane
Acetate
Nit/eel
Acetate
Acetate
_
-
-
—
-
-
10
20
0
40
25
30
Papergrade Sulfite
072
069
060
006
007
052
051
053
058
070
068
181
184
056
062
066
065
067
063
071
059
OG4
147
635(700)
435(480)
204(225)
209(230)
149(164)
100(110)
209(230)
317(350)
127(140)
562(620)
771(850)
390(430)
272(300)
136(150)
161(177)
136(150)
317(350)
104(115)
112(124)
92(102)
218(240)
73(00)
109(120)
1180(1300)
544(600)
366(370)
381(420)
512(564)
100(110)
209(230)
- (-)
127(140)
925(1020)
1179(1300)
1052(1160)
1111(1225)
236(150)
335(369)
408(450)
- C-)
136(150)
221(244)
92(102)
399(440)
245(270)
286(315)
F,N
F,T
F
P,N
N
C,B
F
T
P
T,B,P
T,P
T
B,C,F,P
P
F
T
T
T
F
F
F
G
F
GW
-
NSSC
GW
GW
-
-
-
-
GW,WP
GW,WP
BK
BK,NSSC
-
-
-
-
-
-
-
-
BK
BK
60
06
10
60
100
100
100
100
10
50
100
66
43
25
77
100
-
0
0
5
100
0
0
Wet
Wet
Dry
Wet
Wet
Wet
Dry
Dry
Wet
Wet
-
-
-
-
Dry
Wet
-
Wet
Wet
Dry
Dry
-
-
Wet
Wet
Dry
-
-
-
—
-
-
Yes
Yes
-
-
-
Yes
Yes
-
Yes
Yes
Yes
Yes
-
Yes
-
-
-
Yes
Yes
Yes
-
Yes
Yes
4 -stage
4-stage
Yes
4-stage
-
4-stage
3 -stage
1-stage
cont.
3-stage
3-stage
-
Yes (b)
2 -stage
-
-
3-stage
-
4-stage
-
3-stage
2-stage
Yes
-
-
-
2-stage
-
-
CEHH
CEHH
CEHD
CEH,CEDP,
CEHP
CECHD,CHED
None
CEH,H
CEH
NONE
CEH (a)
NONE
CEH
H
C-H
CEHDP
CEH
CH, CEH, CEHD
CEH,CNH,
CEHD
CEH
CEH
H
H
H
CEH
CEH
CEH
CER
CE/HP
V
S
S
S
B
S
S
NONE
B
S
B
B
B
S
NONE
B,S
S
B
B
B
S
S
B
B
B
S
S
B
NONE
100
100
100
84
100
97
100
75
75
100
100
100
100
0
0
100
100
92
100
5
100
0
0
40
30
70
100
ino
-
Mg
Mg
NH3
Mg
Na
NH3
Mg
Ca/NH3
NH3
Mg
Mg
NH3
NH3
NH3
NH3
Ca
NH3
Mg
Mg
Ca
NH3
Ca
NH3
NH3
Ca
Ca
Mg
Ca
-
B
A
B
A
A
B
B
B
B
B
B
B
A
B
A
B
A/B
B
A
B
B
A
B
A
A
A
B
A
-
34
36
46
47
38
35
50
47
51
46
50
44/68
46
45
47.5
43
43
48
40
50
47
-
45
45
47
47
52
"T
-
97
96
-
98
85
98
95
0
85
98
98
85
81
98
0
85
95(d)
80
81
70
90
95
90
45
86
70
95
Q/l
0
4.5
4.0
-
3.5/5.
(c)
-
3.8-4.
-
3.8
4.2
3.3-3.
2.5-5.
2.0
4.2
-
4.3
2.0
4.2
2.0
2.7
-
2.5-3.
-
2.5
2.2
3.4
-
-
-
5
0
8
0
0
Ta)10-20% of time
(b) Recently installed (data available for both)
(c) Neutralized to 5.5
(d) 95% for one pulping unit, none for the other
-------
TABLE 49
SULFITE MILLS
AGE, LOCATION, CLIMATE, TREATMENT
Hi 11 Age{years)
Dissolving Sulflte
511 23
512 16
050 36
401 18
402 46
403 45
Papergrade Sulftte
072 75
069 77
060 70
006 49
007 67
052 85
051 54
053 6
058 47
070 47
068 43
181 69
184 44
056 122
062 76
066 75
065
067 85
063 77
071 54
059 69
064 72
147
Location
North
North
Southeast
Northwest
Northwest
Northwest
Northeast
Northeast
Northeast
Northwest
Northwest
Northwest
Northwest
East
Northwest
Northwest
Northwest
Northwest
Northwest
Northcentral
Northcentral
Northcentral
Northcentral
Northcentral
Northcentral
Northcentral
Northcentral
Northcentral
Northcentral
Mean Minimum and
Maximum Monthly
Temperature C
Low Hfgh
7.1
0.1
8.8
4.3
4.3
3.6
-15,0
-6.9
-12.2
0
1.1
4.0
3.6
-8,6
4.3
2.6
3.7
4.2
3.4
-7.5
-8.4
-8.8
-8.8
-17.8
-11.1
-17.8
-9,2
-16.1
14.9
13.0
32.0
15.
15.
.9
.9
14.9
27.2
21.0
30.0
28.3
27.7
19.4
19.8
26.6
16.9
16.1
16.9
19,8
17.8
-12.6
22
22
21
21
21
20.0
21.6
21.8
27.0
19.3
Land
Limited
Yes
Yes
No
No
No
Yes
No
No
Yes
No
No
No
No
No
Yes
Yes
Yes
No
No
No
No
No
No
No
Yes
No
No
No
Biological Treatment
In Place Planned
ASB-C
ASB
ASB
ASB
ASB
AS
AS
AS
ASB
AS
AS
ASB
Close
AS
Close
AS
AS
ASB
AS
M
AS
M
TF
AS
AS
Close
-------
evap." presents data from mill questionnaires on the pH of
the SSL prior to evaporation.
The most significant effects upon effluent characteristics
involve the following operations: (1) woodyard, (2) pulp
washing and spent sulfite liquor recovery, (3) type of
condenser, (4) type of cooking liquor, and (5) bleaching.
As discussed in Section IV, the effluent waste loads from
woodyard operations are considered in developing effluent
limitations by the establishment in Section IX of separate
allowances for woodyard operations.
The efficiency of SSL removal from the pulp has significant
impacts on RWL and the two types of systems primarily in use
for separating the SSL from the pulp are (a) blow pit and
(b) vacuum (or pressure) drum. Blow pit washing systems do
not separate the SSL from the pulp as efficiently as vacuum
drum (or pressure) washers and thereby higher effluent
characteristics generally result from mills using blow pit
washing systems. Certainly, the application of SSL recovery
is the most significant factor impacting RWL since without
SSL recovery the BOD5 discharged is in the order of 450
kg/kkg (900 Ibs/ton). Application of SSL recovery reduces
BOD5 levels to 75.0 kg/kkg (150 Ibs/ton) to 125 kg/kkg (250
Ibs/ton) depending upon the degree of efficiency of SSL
recovery. There are still three mills continuing to operate
without SSL recovery and two mills operating with only
partial recovery. It is presently anticipated that all
three mills without SSL recovery will close their sulfite
pulping operations. For example, mill 147 uses sulfite
pulping without SSL recovery in conjunction with bleached
kraft pulping at the same mill. Mill 147 produces 109 kkg
(120 tons) per day of sulfite pulp in addition to the 363
kkg (400 tons) per day of bleached kraft pulp. It is
anticipated that the sulfite pulping at mill 147 will be
shut down with the bleached kraft operation continuing.
Mill 069 which does not have SSL recovery is also planning
to close but the production will be transferred (substitute
production) to a new bleached kraft mill which is being
built by that company near the sulfite mill site. Mill 058
produces approximately 127 kkg (140 tons) per day of
bleached slush pulp without use of SSL recovery and has
planned to shut down the mill since at least 1967.
The data shows that the type of cooking liquor used by
sulfite mills can have some impact on the BOD5 raw waste
load. The impact is due to the use of either very acidic
sulfite cooking liquor (described as acid sulfite) with the
pH of the liquor less than 3.0 or the use of bisulfite
cooking liquors which have a pH between 3.0 and 6.0. Use of
196
-------
either acid sulfite or bisulfite cooking liquor impacts the
BOD5_ load in the condensate. Mills using bisulfite cooking
liquors generally have lesser BODjj loads in the condensate
because of the higher pH of the spent sulfite liquor. This
same effect could be achieved by mills using acid sulfite
cooking liquors by neutralization of the spent cooking
liquor but this internal control is only practiced by a few
mills and is thus not considered part of the BPCTCA (See
Table 50 for BODS load reductions associated with
neutralization) . Therefore, a separate allowance has been
established in Section IX for mills using acid sulfite
cooking liquors because of the higher raw waste loads
experienced by those mills.
The use of barometric type condensers in the SSL recovery
system generally results in higher flows than the use of
surface or vapor recompression type condensers. In
addition, the bleaching, ranging from one to five stages,
can have some impact on effluent characteristics, and data
have shown that the primary differences between mills are in
the production of either bleached pulp and paper or
unbleached pulp and paper. Differences in effluent
characteristics are not apparent between mills with
different bleaching sequences, such as a mill with one
stage, H, or a mill with the most common sequence of three
stages, CEH. As presented in the bleached kraft discussion,
papermaking can also have impacts on RWL but for sulfite
mills, the impact of papermaking is relatively less
significant than the other factors discussed above. Thus,
as shown by the data presented in Table 47, the most
significant impacts on raw waste load at sulfite mills
include the following: the degree of recovery (blow pit
washing or vacuum (or pressure) drum (or belt extraction)
washing, the type of condensers (barometric or surface), the
type of cooking liquor (acid or bisulfite), and the use of a
bleaching process. In addition, one mill uses a continuous
digester for pulping and because of operational difficulties
experienced by the mill due to the use of sulfite liquor and
the continuous digestion process, the mill reports higher
raw waste loads than mills using batch digesters. As
discussed in Section IV, two subcategories were established,
blow pit washing and vacuum drum washing, with allowances
for barometric or surface condensers, acid or bisulfite
cooking liquor, and for continuous digesters.
The raw waste loads for the blow pit and drum wash
subcategories and the allowances for barometric/surface
condensers and type of cooking liquor were derived from the
data presented in Tables 51, 52 and 53. The flow averages
were determined using mills in both blow pit and drum wash
197
-------
Table 50
Inpact of Neutralization of SSL
on Condensate BOD 5 Levels
kg/kkg/ (Ibs/ton)(a)
BOD5
Uncollected
SSL pH Condensate Bleach Plant Total
3.0 70 (140) 40 (80) 110 (220)
4.0 60 (120) 40 (80) 100 (200)
5.0 50 (100) 40 (80) 90 (180)
6.0 40 ( 80) 40 (80) 80 (160)
7.0 30 ( 60) 40 (80) 70 (140)
(a) Data in unbleached production
198
-------
Table 51
Papergrade Sulfite (Blow Pit Wash) Subcategory
Raw Waste Characteristics
Mill Flew BOD 5
kl/kkg (kgal/ton) kg/kkg/ (Ibs/ton)
Bisulfite
070 ( - ) 107 (214)*
056 231 (55.3) 116 (232)
052 170 (40.8) 79.0 (158)*
Ave. ( - ) 116 (232)
Acid Sulfite
071 208 (49.9) 121 (242)
051 251 (60.2) 114 (227)*
064 - ( - ) 105 (210)*
063 199 (47.8) 89.0 (178)*
Ave. ( - ) 121 (242)
Not used in average (see text)
199
-------
Table 52
Papergrade Sulfite (Drum Wash) Subcategory
Raw Waste Characteristics
Mill Flow BCD 5
kl/kkg (kgal/ton) kg/kkg (Ibs/ton)
Bisulfite
062 174 (41.7) 74.5 (149)
059 173 (41.4) 110 (220)
053 86.7 (20.8) 95.5 (191)
006 117 (28.0) 62.5 (123)
007 176 (42.1) 44.9 (89.7) *
065 197 (47.2) 77.5 (155)
Ave. - 84.0 (168)
Acid Sulfite
068 254 (61.0) 112 (223)
066 186 (44.7) 192 (383)*
051 248 (59.4) 95.0 (190)
Ave. 104 (207)
Not used in average (See Text)
200
-------
Table 53
Papergrade Sulfite Subcategories
Barometric and Surface Condensers
Raw Waste Characteristics
Mill Flow
056
052
063
051
007
065
060
071
062
059
053
006
068
066
kl/kkg
Barometric Condensers
231
170
199
251
176
197
227
Ave. 221
Surface Condensers
208
174
173
86.7
117
254
186
Ave. 186
(kga I/ton)
(55.3)
(40.8)*
(47.8)
(60.2)
(42.1)*
(47.2)
(54.5)
(53.0)
(49.9)
(41.7)
(41.4)
(20.8)*
(28.0)
(61.0)
(44.7)
(44.5)
Not included in average (See text)
BCDS
kg/kkg (Ibs/ton)
116 (232)
79.0 (158)
89.0 (178)
114 (227)
44.9 (89.7)
77.5 (155)
140 (279)
121 (242)
74.5 (149)
110 (220)
95.5 (191)
61.5 (123)
112 (223)
192 (383)
201
-------
subcategories as shown in Table 53f since differences in
flow between mills are primarily related to the type of
condensers used by the mills and not to the type of pulp
washing equipment or type of cooking liquor. The
differences in RWL BOD5_ attributable to differences in
cooking liquor are due to the differences in the pH of the
SSL going to the evaporators resulting in different
condensate BOD5_ loads. The differences in the pulp washing
equipment is in the efficiency of SSL recovery and it would
not be expected that flow would be impacted, only the BOD£.
This is demonstrated by mill 051 which recently replaced the
blow pit washing system with a vacuum belt extraction system
(similar to vacuum drum washing). Data were available for
both periods of operation and while the BOD5 raw waste load
was reduced from 113.5 kg/kkg (227 Ibs/ton) to 95 kg/kkg
(190 Ibs/ton), the flow remained essentially the same, 251
kl/kkg (60.2 kgal/ton) versus 248 kl/kkg (59.4 kgal/ton),
respectively. Therefore, the average subcategory flow for
barometric condensers was the same in both the blow pit and
drum wash subcategories and similarly for surface
condensers.
Several of the data points included in Tables 51, 52 and 53
were not included in determining the subcategory averages
because of the reasons discussed below. In Table 53, the
flows for mills 052 and 007 were excluded because the mills
do not bleach their pulps. Mill 053 was excluded because,
being constructed in the late 1960s, the mill segregated the
pulp mill and paper mill waste streams which resulted in
significantly lower flows. In Table 51, mill 052 was
excluded because the mill does not bleach the pulp, and mill
070 is a complex mill for which a representative BOD5_ raw
waste value was not available. The 107 kg/kkg (214 Ibs/ton)
was derived by excluding the contribution of purchased pulp
but the mill also includes waste paperboard production,
chemi-mechanical pulp production, and a chemical by-product
plant. Thus, a representative BOD5_ raw waste load for the
sulfite pulp and paper production could not be calculated.
Because of differences in the data, it was determined to be
most appropriate to use mill 071's EOD5_ raw waste load
(which was the highest of the four mills) to represent acid
sulfite blow pit sulfite production and exclude mills 051,
063, and 064. In Table 52, mill 007 was excluded because
the mill does not bleach and mill 066 was excluded because
the data for the mill in the table is inconsistent with
previous data for that mill. The mill reported that in-
plant controls had been installed but the more recent data
showed a very large increase in the BOD.5 raw waste load, 130
kg/kkg (260 Ibs/ton) to 191.5 kg/kkg (383 Ibs/ton). The
mill management only accounted for approximately 20 kg/kkg
202
-------
(40 Ibs/ton) of the increase and thus the data was excluded.
It should be pointed out that in every case except for mill
066, inclusion of the excluded mill data points in averages
presented in Tables 51, 52 and 53 would result in lower raw
waste BOD5_ and flows.
Table 54 summarizes the raw waste loads which were
determined for each of the subcategories and allowances from
the data in Tables 51, 52 and 53. In addition, an allowance
for the mill using a continuous digester is provided in
Section IX, and the allowance was based upon the mill's raw
waste flow and BOD5_ (mill 060) of 227 kl/kkg (54.5 kgal/ton)
and 139.5 kg/kkg (279 Ibs/ton), respectively. As discussed
previously, TSS was not used as a basis for
subcategorization or for the effluent limitations (final
effluent TSS is more related to raw waste BOD5 than raw
waste TSS) . Because of this, TSS data were not presented in
Tables 51-54. The raw waste TSS used in developing the
costs presented in Section VIII were averages of mills 051,
066, and 071 from previous representative data periods. The
average raw waste TSS for these mills was 89.5 kg/kkg (179
Ibs/ton).
Dissolving Sulfite Subcategory
Over 60 percent, frequently up to 70 percent, of the wood
used to produce sulfite dissolving pulp becomes waste. This
organic material is carried away in the effluent streams
(159). The major areas of its concentration are the spent
cooking liquor ("red liquor") evaporator condensates, side-
hill screen rejects, and bleach plant effluent (159).
In this pulping process, the spent liquor carries a very
heavy solids load since cooking is continued until most of
the lignin and part of the cellulose are dissolved (180).
As a result, four stages of washing, usually countercurrent,
are generally required. This removes about 95 percent of
the lignin from the pulp (180) which in turn generates a
larger solids load in the evaporator condensate of
dissolving sulfite mills than is the case with sulfite mills
producing papermaking grades.
The side-hill screens (equipment unique to dissolving pulp
manufacture which is used in addition to conventional
screens) thicken the pulp and can account for approximately
18.9 kl/min (5000 gpm) of waste water which contains about
three percent of the pulp, ray cells, sand, and residual red
liquor (180) (159) .
203
-------
Table 54
Papergrade Sulfite Subcategories
Sunrnary of Raw Waste Characteristics
Subcategory Flow BCO5
kl/kkg (kgal/ton) kg/kkg (Ibs/ton)
Blow Pit Wash
Bisulfite/Barometric 221 (53.0) 116 (232)
Acid Sulfite/Barometric 221 (53.0) 121 (242)
Bisulfite/Surface 186 (44.5) 116 (232)
Acid Sulfite/Surface 186 (44.5) 121 (242)
Drum Wash
Bisulfite/Baroretric 221 (53.0) 84 (168)
Acid Sulfite/Barometric 221 (53.0) 104 (207)
Bisulfite/Surface 186 (44.5) 84 (168)
Acid Sulfite/Surface 186 (44.5) 104 (207)
204
-------
A great deal of material, including beta and gamma
cellulose, is extracted from dissolving pulp in bleaching
(5) (52). The caustic extraction stage alone dissolves about
10-16 percent of the pulp, depending on the grade of
cellulose desired (180). The wash water from this stage is
much higher in BOD5_ than the comparable stream in the
bleaching of sulfite papermaking pulps.
The hypochlorite stages create further losses but little
BOD5_ load since the cellulose modification they perform is
an oxidizing process (180) .
Sulfite dissolving bleachery effluents contain from 50 to
100 kg/kkg (100 to 200 Ib/ton) of total suspended solids.
As reported by two sources, the BODj> ranges from 100 to 225
kg/kkg (200 to 450 Ib/ton) (91) (5). The pH value ranges
between 2.0 and 3.0 and the electrolyte content is usually
about double that of sulfite papermaking bleachery
effluents.
Mills 401 and 511 practice spent sulfite liquor (SSL)
recovery and obtain raw waste BOD5_ loadings of 136 kg/ kkg
(271 Ib/ton) and 130 kg/kkg (260 Ib/ton), respectively.
Mill 050 has recently installed an SSL recovery system and
prior to start-up the BOD5_ raw waste loading was 740 kg/kkg
(1480 Ib/ton). The mill projects that this value will drop
to 137.5 kg/kkg (265 Ib/ton) when operating at its design
efficiencies.
Flow from surveyed dissolving sulfite mills varies from 246
to 275 kl/kkg (58.9 to 66.0 kgal/ton). TSS data are limited
and only data for mill 511 were available which had a TSS
raw waste of 92.5 kg/kkg (185 Ib/ton).
As discussed in Section IV, mills within the dissolving
sulfite pulp subcategory produce four different grades of
pulp including (1) nitration, (2) viscose, (3) cellophane,
and (4) acetate which are described primarily by the degree
of purification of the pulp. Process differences between
mills relate to the pulping and bleaching operations. The
most significant difference is in the bleaching operations
and specifically in the second stage of bleaching, the
caustic extraction stage. Mills producing the highest grade
of pulp, acetate grade, use a very strong caustic liquor in
the extraction stage resulting in yield losses during
caustic extraction of 24% and higher.
Several parameters are used for determining the grade of
pulp including yield loss, shrinkage in the hot caustic
extraction stage, viscosity, alpha content, caustic usage,
205
-------
and the percentage of pulp which is soluble in 18% NaOH at
20°C (S18). Available data show that use of alpha content
and viscosity to define the different grades of pulp is
complexed by the fact that some overlap in values is
experienced between the grades. Use of yield loss,
shrinkage in the hot caustic extraction stage, amount of
caustic consumed, and the S18 values tend to be somewhat
more descriptive of the grades of pulp. These parameters
are presented in Table 55 for each grade of pulp (309).
The yields shown in Table 55 for the dissolving sulfite
mills were derived from the background information from
Reference 29 and do not entirely agree with the above yield
ranges for each grade. The differences may relate to the
fact that the information from Reference 29 did not specify
the grade of pulp associated with the yield data, and
several of the mills produce more than one grade of
dissolving pulp as well as producing some papergrade pulp.
As discussed previously, the key step in the production of
the various grades of dissolving pulp is the caustic
extraction stage in the bleaching process. In this stage of
bleaching, caustic is largely consumed by degradation
reactions of the hemicelluloses and the more caustic that is
consumed, the greater the purification, the more
hemicelluloses removed, the lower the yield, and the more
BOD5 generated. In order to achieve the higher grades of
pulp, increased temperatures in the caustic extraction stage
are frequently used ranging from 100°C for nitration grade
pulps to 1UO°C for acetate grade pulps.
Figure 40 is presented to show the relative contributions of
the basic unit processes to the total waste load for a
dissolving sulfite mill with the effluent characteristics
shown.
Developmentof Subcategory Raw Waste Loads
The development of the raw waste loads (RWL) for the
dissolving sulfite subcategories is discussed below. The
resultant raw waste loads were used in developing the
effluent limitations for each subcategory and in determining
the costs presented in Section VIII.
The dissolving sulfite subcategories includes six mills,
five of which are located in the Pacific Northwest (and
Alaska), and one is located in Florida. Information and
data on manufacturing operations and effluent
characteristics were collected for effluent limitations
development by on-site surveys at all six mills. In
addition to the information and data collected during the
206
-------
Table 55
Characteristics of Dissolving Sulfite Pulps (309)
Grade of Shrinkage in Hot Total
Pulp Caustic Extraction Stage Yield
Nitration
Viscose
Cellophane
Acetate
8-12
13-17
17-20
24 and above
37
36
34
31
Caustic
Consumed S18
kg/kkg (Ibs/ton) %
144 (288)
125 (250)
150 (300)
175 (350)
5.3-6.5
4.5-5.3
2.9-4.5
<2.9
207
-------
FIGURE 40
EFFLUENT CHARACTERISTICS: SULFITE DISSOLVING MILL
PROCESS
WATER
PULP MILL
AND
LIQUOR RECOVERY
25,000 GAL/TON
60 LB BOD5/TON
BLEACH PLANT
AND
PULP DRYER
41,000 GAL/TON
205 LB BOD5/TON
RAW
WASTE
66,000 GAL/TON
265 LB BODc/TON
185 LB TSS7TON
203
-------
mill surveys, Reference 29 provided supplementary
information and data in the form of a published report and
the supporting raw data sheets which were summarized in the
report.
Tables 48 and 49 present available information and data for
each of the six mills. As shown in Table 48, the only mill
that uses blow pit pulp washing and barometric condensers is
mill 402 and thus, BPCTCA for the dissolving sulfite
subcategories includes full SSL recovery with four stage
vacuum drum pulp washing using surface or vapor
recompression condensers (See Sections VII and VIII). The
selection of the internal controls portion of BPCTCA as
above represents a somewhat different situation for
dissolving sulfite mills than, as previously discussed, for
papergrade sulfite mills. Five of the six dissolving
sulfite mills are using four stage vacuum drum pulp washing
and surface or vapor recompression condensers, whereas
approximately half of the papergrade sulfite mills are still
using blow pit pulp washing and barometic condensers. Thus,
the internal controls portion of BPCTCA for dissolving
sulfite mills represents a higher degree of control than
does the papergrade sulfite technology.
Determination of raw waste loads associated with the
production of the four grades of dissolving sulfite pulp was
based upon information and data from a number of sources
including mill surveys and mill data, literature, and
correspondence with companies involved in dissolving sulfite
manufacture. Since three of the six mills use bisulfite
cooking liquor and because separate allowances are
established in Section IX for the four grades of pulp, it
was determined to be most appropriate not to establish a
separate allowance for bisulfite cooking liquor but to add
to the raw waste loads for those mills an equivalent amount
of BOD5_ that would represent the impact of bisulfite cooking
liquor. Table 50 presents BOD5_ data associated with
neutralization of SSL which can also be used as a basis for
the difference between the expected raw waste load from
mills using acid sulfite or bisulfite cooking liquors (29).
Other sources have reported the impact of neutralization to
be approximately 17.5-20.0 kg/kkg (35-40 Ibs/ton) (349).
Therefore, in determining representative BOD5_ raw waste
loads for each grade of pulp, a value of 20 kg/kkg (40
Ibs/ton) was added to the reported BOD5_ raw waste loads for
those mills which either used bisulfite cooking liquors or
that neutralized the SSL. Table 56 summarizes the data used
in determining the raw waste loads and Table 57 summarizes
the raw waste loads used in determining the costs in Section
VIII and the effluent limitations in Section IX.
209
-------
The data presented in Table 56 has been carefully examined
and in a number of cases the presented data is a result of
some adjustment of the raw data in order to present data of
a common basis. For example, mill 402 produces both
papergrade and dissolving pulps and the raw data was
adjusted (see bleached kraft discussion for similar type
calculations) to represent production of only dissolving
pulps. Mill 401 also produces both papergrade and
dissolving pulps but at separate times. Thus/ data
representing only the production of dissolving pulp at mill
401 was used in determining the raw waste loads. The BOD5_
data presented for mill 403 represents full recovery of the
SSL (95%) and the data required adjustment to full recovery
because the mill's SSL system is still in start-up stages
and recovery efficiencies appear to be in the range of 70 to
80%. The flow data presented for mill 403 is equivalent to
the flow that the mill has reported that will require
treatment after separation of cooling waters. It should
also again be noted that data for mills 512, 401, and 511
have been increased by 20 kg/kkg (40 Ibs/ton) to take the
impact of SSL neutralization or use of bisulfite cooking
liquor into account.
The raw waste flow of 275 kl/kkg (66.0 kgal/ton) in Table 57
which was used for each of the pulp grades is based not on
the average flow for each grade but on the flow from mill
401 (highest raw waste flow of all the mills). Differences
in flow between grades are not expected except for the
impact of yield on total production, since the process
differences between grades of pulp relate primarily to the
caustic extraction stage in the bleaching process where
operating parameters of temperature, time, and chemicals are
varied, not the use of process water. Therefore, since the
data showed flows in a relatively narrow range of 246 kl/kkg
(59 kgal/ton) to 275 kl/kkg (66 kgal/ton), the raw waste
flow for all pulp grades was conservatively determined to be
275 kl/kkg (66 kgal/ton).
The data presented in Tables 56 and 57 represents the
production of dissolving pulp from softwoods. Mill 401
reported that hardwoods had a significant impact on the raw
waste loads over production with the use of softwoods. The
mill reported that production of nitration grade pulp using
softwood resulted in a BOD5_ raw waste load of 118 kg/kkg
(236 Ibs/ton) whereas use of hardwoods to produce nitration
grade pulp resulted in BOD5_ loads of 166 kg/kkg (332
Ibs/ton). Since mill 401 is the only mill using appreciable
amounts of hardwood, the raw waste loads and effluent
limitations in Section IX are based on pulp production from
softwoods. It should be noted that mill 403 reportly uses
210
-------
Table 56
Dissolving Sulfite Pulps
Raw Waste Characteristics
Flow
kl/kkg (kgal/ton)
BOD5
kg/kkg/ (Ibs/ton)
Source
Remarks
Nitration Grade
Ave. -
136
138
(272)
(276)
137 (274)
(a)
(b)
Added for Neut.
Viscose Grade
246 (58.9)
163 (325)
150 (299)
(a)
Mill 512
Added for Neut,
Ave. 246 (58.9)
156 (312)
Cellophane Grade
275 (66.0)
269 (64.4)
Ave. 272 (65.2)
Acetate Grade
274 (65.8)
274 (65.8)
256 (63.8)*
Ave. 274 (65.8)
176
187
156
143
(352)
(374)
(311)*
(286)*
(a)
(b)
Mill 401
Mill 511
182 (363)
209
195
(417)
(390)
Mill 050
Mill 402
Mill 403
Added for Neut.
Added for Neut.
Added for Bisulfite
See Text
See Text
202 (404)
* Not included in average
(a) American Paper Institute
(b) Weyerhauser Corp.
211
-------
Table 57
Dissolving Sulfite Pulps
Summary : Raw Waste Characteristics
Grade of Pulp Flow BOD5
kl/kkg (kgal/ton) kg/kkg (Ibs/ton)
Nitration 275 (66.0) 137 (274)
Viscose 275 (66.0) 156 (312)
Cellophane 275 (66.0) 181.5(363)
Acetate 275 (66.0) 202 (404)
212
-------
approximately three per cent hardwoods in the mill's pulp
production, but this is not considered to be a significant
factor in the mill's waste loading because of the small
percentage of hardwoods used.
Each of the dissolving sulfite mills for which flow data
were available have wet barking operations (except mill 050)
and the effluent generated from these operations are
included in the mill's reported raw waste loads. Because
the flow data was directly included in the raw waste flows
used in determining the effluent limitations, and the BOD5_
data were partly from actual mill data and partly from
correspondence with companies reporting BOD5_ loads
associated with specific grades of pulp, the debarking
allowances in Section IX were determined using only the BOD5_
loads shown previously in Table 57 and not the flows (the
flows from the debarking operations were already included in
the subcategory averages). The exception is mill 050 whose
flow shown in Table 56 is from a period prior to the
installation of SSL recovery and it is expected that the
mill's flow would decrease significantly now that the SSL
recovery system is operating.
213
-------
BLEACHED KRAFT SUBCATEGORIES
Effluent volume from the kraft pulping operation alone
ranges from 41.7 to 10U kl/kkg (10.0 to 25.0 kgal/kkg).
This volume depends upon the grade of pulp manufactured,
further processing which may be involved, and cooling water
requirements. The latter vary with the type of condensing
devices employed in the mill as well as local ambient water
and air temperatures. Except where salt or brackish water
is used for cooling, the water is frequently reused as
process water. Also, mills which produce unfilled paper can
return a considerable amount of white water to the pulp mill
which replaces a substantial portion of fresh water
(87) (58). Water use in all kraft mills is integrated to
some degree among the various subprocesses which results in
considerable dilution of the pulping waste. The major waste
streams are digester and evaporator condensates, decker seal
pit water, and the recovery plant effluent although in some
of the older mills these individual streams are seldom
separated (59) (60) (54). The recovery stream generally
contains miscellaneous waste waters such as floor and tank
apron drainings and storage tank overflows. In addition,
boiler plant and water treatment plant wastes are sometimes
sewered with the recovery unit. In other mills they are
discharged to lagoons with the water-borne solid wastes such
as fly ash, grits, and dregs.
Figure U1 summarizes the unit process waste characteristics
of a bleached kraft mill with the effluent characteristics
that are shown. The figure is presented to show the
relative contributions of the unit processes to the total
raw waste load, but should not be interpreted as
representing the typical bleached kraft mill.
The quantity of the various materials in the effluent stream
depends to a considerable degree on the efficiency of the
recovery and associated operations as well as the
effectiveness of provisions for handling cleaning
operations, process upsets, and equipment failures. The
very high efficiency of modern recovery installations
results, as a general rule, in lower losses than those of
older units. Many older mills have completely rebuilt or
replaced the original equipment and reach efficiency levels
similar to those of new mills (58). Examples from surveyed
mill data support this conclusion and have been presented in
Section IV. High sewer losses will invariably occur,
however, when these systems are overloaded irrespective of
their age. Variations in raw waste quality will also occur
throughout periods of normal operation (62) due to
214
-------
FIGURE 41
EFFLUENT CHARACTERISTICS: BLEACHED KRAFT MILL
PROCESS
WATER
WOODYARD
PULP MILL
RECOVERY
AND
CAUSTICIZING
BLEACH PLANT
PAPER MILL
215
1,000 GAL/TON
2 LB BOD5/TON
8 LB TSS/TON
15 LB COLOR/TON
7.5pH
6,000 GAL/TON
23 LB BODg/TON
17 LB TSS/TON
65 LB COLOR/TON
9.6pH
5,000 GAL/TON
10 LB BOD5/TON
27 LB TSS/TON
5 LB COLOR/TON
8.4pH
I 1,000 GAL/TON
16 LB BODg/TON
9 LB TSS/TON
65 LB COLOR/TON
2.0pH
(ACID WASTE)
(ALKALINE WASTE)
8,000 GAL/TON
15 LB BOD5/TON
5 LB TSS/TON
145 LB COLOR/TON
!0.2pH
8,000 GAL/TON
12 LB BOD5/TON
34 LB TSS/TON
5 LB COLOR/TON
7.1 pH
RAW
WASTE
39,000 GAL/TON
78 LB BOD5/TON
100 LB TSS/TON
300 LB COLOR/TON
215
-------
irregularities in equipment operation as well as periodic
wash-up procedures which contribute to the sewer losses.
Pollutional components of kraft pulping effluents include
suspended solids, dissolved organics, and electrolytes.
Also, inorganic ions are attached to organic compounds such
as lignins, resins, and fatty acids.
The quantity of total suspended solids can vary widely but
on the average runs between 20 to 30 kg/kkg (40 to 60
Ibs/ton) for well operated mills. They are largely fiber
fines and wood debris plus about five to 10 percent
dispersed inorganic material. They account for from 10 to
20 percent of the five-day BOD5 and contribute substantially
to the COD. Most of the total suspended solids are settle-
able (63), and the resulting sludge thickens well and
dewaters readily by established means. The sludge cakes are
low in ash and can be incinerated (61)(65).
The dissolved organics fall into two classes: those which
are amenable to biological decomposition and those which are
not. The former include methanol, ethanol, turpenes,
acetone from the condensates, (66)(67) and fatty acids, and
other cellulose decomposition products of spent cooking
liquor origin (68) (60). This fraction accounts for over 80
percent of the BOD5_ of kraft mill effluent. The average
BOD5_ load amounts to 12.5 to 25 kg/kkg (25 to 50 Ib/ton) and
the concentration of the final effluent generally ranges
from 150 to 300 mg/1 (59) (54). Data from three surveyed
mills tends to support these figures. Mill 103, for
example, has a pulp mill effluent BOD5 load of 18.45 kg/kkg
(36.9 Ib/ton). The comparable figure for Mill 108 which is
a dissolving pulp mill is 23.5 kg/kkg (47.0 Ib/ton) and for
Mill 122 is 17.5 kg/kkg (35.0 Ib/ton).
The non-degradable organic fraction is largely responsible
for the color of kraft effluents. It is generally caused by
lignins and tannins and is commonly measured by comparison
with the platinum-cobalt standards. Based on this standard,
kraft pulping effluents normally contain from 500 to 2000
mg/1 of color units during periods of normal operation.
This amounts to 50 to 400 kg/kkg (100 to 800 Ib/ton) of
color units (69)(70). These values can rise considerably if
carry-over in the black liquor evaporators or pulp washing
problems occur.
Both degradable and refractory organics contribute to the
COD of kraft pulping effluents which is a measure of the
total oxidizable content of the waste. Together with some
inorganic sulfides they produce COD values of 500 to 950
216
-------
mg/1 in normal mill effluents (71). Roughly 37.5 to 75
kg/kkg (75 to 150 Ib/ton) of COD of product are ususally
discharged from these mills. No fixed ratio between the
BOD5 and COD has been established.
A number of other oxidation methods have been employed for
analyzing kraft pulp mill waste waters (72). The most
noteworthy of these is a technique using combustion and
infrared detection of the carbon dioxide formed (73). This
technique measures total carbon (TC), but it has been
modified to measure total organic carbon (TOC) and total
organic matter (TOM) from which the total oxygen demand
(TOD) can be computed. TOD values developed by this method
correlate well with COD test data (72). However, since the
BOD5_ values measure only readily biologically oxidized
materials and the ratio of these substances to the total or-
ganic content of kraft effluents fluctuates continually, no
correlation between BOD5_ and total chemical oxygen
consumption can be anticipated. Because of the complexity
of operation and instrument cost, the infrared methods have
been largely limited in application to research and as a
measure of the effectiveness of advanced waste treatment
systems. However, «*hen fully developed they may be adapted
to effluent monitoring (7U) .
Substances harmful in very low concentrations to aquatic
life have been found in kraft pulping effluents. These
consist mainly of sulfides, mercaptans, resin acids, fatty
acid soaps, and turpenes (75) (76), but some less common and
more complex compounds demonstrating toxic properties have
also been identified (77). Generally these substances are
present in concentrations of less than five mg/1. Some of
them, such as sulfides and mercaptans, are rapidly destroyed
by natural oxidation but others, such as resin acid soaps,
are more stable. They are, however, removed by biological
treatment and it has been demonstrated that toxicities of
kraft mill effluents are significantly reduced by biological
treatment (78).
The electrolyte content of kraft mill effluent normally
ranges from 1500 to 3000 mg/1. The salts comprising this
fraction of the waste derive from the mill's water supply,
paper machine white water used in the pulp mill, the pulping
process, and boiler blow-down. Those contributed by process
are mainly sulfates and carbonates of sodium and calcium
together with some more complex sodium compounds containing
sulfur. Most effluents are almost devoid of nitrogen and
phosphorus compounds although in some instances, phosphates
are present due to their use in boilers and detergents.
217
-------
The pH of the pulping effluent is on the alkaline side
ranging normally from 9.0 to 10.0 due to the presence of
sodium carbonate. From time to time a small amount of
sodium hydroxide drives this value somewhat higher.
Ordinarily, however, the total alkalinity is low
particularly when paper machine white water which contains
some acidity is used in the pulp mill.
The condensates and drainings from prehydrolysis of the
chips in kraft dissolving pulp mills contain wood solubles
with a BOD5 value of 30 to 60 kg/kkg (60 to 120 Ib/ton) for
softwoods and 90 to 100 kg/kkg (180 to 200 Ib/ton) for
hardwoods and amount to approximately 0.13 kl/kkg (0.3
kgal/ton) in volume (79). These condensates and drainings
are normally evaporated and burned in the recovery boiler.
The manufacture of chlorine or caustic soda for pulp
bleaching produces a small amount of inorganic waste
containing impurities from the purchased salt (mainly salts
of the alkaline earth metals) together with some unreacted
sodium chloride. Pulp mills no longer employ mercury cells
in producing chlorine (94). Therefore, generally only very
low levels of mercury are found in the effluent. There are
two operations located adjacent to pulp mills in which
chlorine and caustic are produced by this method but these
are classified as chemical plants and are subject to
separate effluent limitations (45).
The only waste produced by hypochlorite manufacture is
washout from the absorption towers employed. The solids
contained in the waste are inorganic in nature, containing
insoluble impurities present in the chemicals, such as
silica and sulfates of alkaline earth metals.
The wastes from the manufacture of chlorine dioxide are
concentrated solutions which amount to 4.17 to 8.3 1 (0.5 to
1.0 gal) per kg (Ib) of C102 produced, or about 25 to 42 1
(6 to 10 gal) per kkg (ton) of pulp bleached. They consist
primarily of sodium sulfate and sulfuric acid, together with
a small quantity of residual chemicals which vary with the
process employed. Because of their sulfuric acid content,
they are sometimes employed in converting soap skimmings to
tall oil before they are introduced into the kraft recovery
system as chemical make-up (24). In this step the acid
present is converted to sodium sulfate, the primary make-up
compound, and, on the average, such wastes can supply up to
25 percent of the total salt cake make-up of the kraft mill.
By 1969, all but five of 67 bleached kraft mills producing
chlorine dioxide disposed of the waste in the recovery
218
-------
system, although there is wide variation as to the point
where it is introduced. Through this procedure most of the
inorganic chemical is converted to white liquor constituents
(NaOH and Na2S), and when unreacted methanol is present, it
is burned in the recovery furnace.
Other chemicals are used in the bleaching process in
relatively small quantities and contribute to the mill
effluent only to a very minor degree.
Effluent from modern bleach plants is normally discharged
only from the chlorination and extraction stages since
effluents from other stages are reused utilizing
countercurrent washing techniques.
The combined effluent contains the impurities from the
process water supply, substances extracted from the pulp,
and chemicals added in the process in modified form. For
example, caustic soda appears as the cation of the extracted
organics. Because of the dilute nature of the effluents and
their chloride content, their introduction into the kraft
recovery system is not presently feasible.
The major polluting factors contributed by bleaching
effluents to surface waters are BOD5, color, and pH,
although chlorides, COD, and suspended solids must also be
considered. Figures for BODS, suspended solids, and color
which were derived from a previous study are presented in
Table 58 (5). These data may be compared to that obtained
from surveyed mills as shown in Table 59. Flow, for
example, is much lower than reported in Table 58, ranging
from 6.0 to 90.4 kl/kkg (1.44 to 21.67 kgal/ton). Likewise,
BOD5_ is significantly lower in surveyed mills, ranging from
1.25 to 16.0 Jcg/kkg (2.5 to 32 Ib/ton), whereas that
reported in Table 58 suggests a minimum value of 15 kg/kkg
(30 Ib/ton). Similarly, both TSS and color, as obtained
from surveyed mills, are significantly lower than reported
in Table 58. No clear cut explanation can be made of these
differences, but it is logical to assume that the surveyed
mill results, which represent 1972-3 operation, reflect the
beneficial effects of recent efforts directed toward water
conservation and reuse (particularly by jump stage counter-
current washing) , whereas the data reported in Table 58
represent operations prior to 1970. A breakdown of the
contribution of the various stages of the CEDED bleach plant
is shown in Table 60 (81). Flow from a five stage bleachery
has been reported about 41.7 kg/kkg (10.0 kgal/ton). The
solids and chloride losses for this type of bleaching are
shown in Table 61.
219
-------
Table 58
VOLUME AND CHARACTERISTICS OF KRAFT BLEACHERY WASTES (5)
Effluent
Volume
1000 1/kkg
(100 gal. ton)
Semi-Bleaching
ro
o
High-Bleaching
Dissolving Pulp (Soft Wood)
Dissolving Pulp (Hard Wood)
75-104
(18-25)
104-146
(25-35)
209-250
(50-60)
230-289
(55-70)
BOD
kg/kkg
(Ib/ton)
15-17.5
(30-35)
20-30
(40-60)
60-75
(120-150)
250-350
'500-/00)
Total S..sp.
Solids Color
kg/kkg mg/1
7.5-10 2500-3000
(15-20)
10-15 4000-6000
(20-30)
65-75 >5000
(130-150)
95-100 >5000
(190-200)
PH
Range
4-5
3-4
2-3
2-3
-------
Table 59
KRAFT BLEACHING RAW WASTE CHARACTERISTICS (BLEACH PLANTj_
ro
ro
MILL
CODE
100
101
103
104
108
117
122
124
125
FLOW
kl/kkg
23.7
30.2
70.3
40.0
90.4
39.1
23.9
6.0
42.2
(kgal/ton)
(5.69)
(7.24)
(16.86)
(9.59)
(21.67)
(9.37)
(5.73)
(1.44)
(10.12)
BOD
kg/kkg
4.55
10.9
12.9
1.25
12.11
16.0
4.78
2.52
7.52
(Ib/ton)
(9.09)
(21.83)
(25.77)
(2.50)
(24.23)
(32.0)
(9.55)
(5.04)
(15.03)
TSS
kg/kkg
2.88
2.24
3 . 21
O.S6
l.'-.S
4 . ">8
2.94
9.51
1.95
(Ib/ton)
(5.76)
(4.48)*
(6.41)*
(1-72)
(2.39)
(9.17)*
(5.88)
(19.02)*
(3.90)*
COLOR
rr.3/1 kp,/kkt; (lb/ ton)
525 15.9 (31.74)
1326 51.9 (103.8)
1397 8.4 (16.8)
* TSS(N)
25.4
(50.8)
-------
Table 60
RAW WASTE CHARACTERISTICS OF
VARIOUS STAGES OF BLEACHING
ro
ro
ro
Bleaching Stage
Chlorination
Extraction
Finishing Stages (BED)
Total
kg/kkg
O.b/ton)
BODS
5.0
(10.0)
7.1
(14.2)
5.5
(11.0)
17.6
(35.2)
Color (pr.)
43.8
142.2
21.9
-------
Table 61
CONSTITUENTS OF FIVE STAGE BLEACHING EFFLUENT
9/ton (3
7% Shrinkage
Total Dissolved Solids 340
Dissolved Inorganics 205
Dissolved Organics - 135
^ Cl - from Chlorine 125
ro Cl - from Dioxide 16
NaOH 50
Na2S04 14
-------
Effluent concentrations at a water usage of 41.7 kl/kkg
(10.0 kgal/ton) will amount to around 400 mg/1 of BOD5, 1600
mg/1 COD, and 2400 mg/1 of color for the combined waste of a
five-stage bleachery.
The pH value of the combined waste is on the acid side due
to mineral acidity from hydrochloric acid formed by reaction
of the chlorine compounds employed. The degree of acidity
depends upon the amount of active alkali remaining in the
caustic extract and the neutralizing chemical used after the
final chlorine dioxide stage. These effluents generally
range from pH 3.0 to 4.0.
The overall shrinkage in kraft pulp weight during bleaching
ranges from four to ten percent and is due mainly to the
removal of dissolved substances since fiber losses are
generally less than 0.5 percent. This accounts for the
normally lower suspended solids content of kraft bleaching
effluents and explains why these wastes are frequently by-
passed around clarification devices at pulp mills.
The simple dissolved organics present in bleachery effluents
are low molecular weight substances (83). They primarily
include methanol, methy-ethyl ketone, and formic acid
although small quantities of oxalic, malonic, fumaric, and
succinic acids, and acetaldehyde are also present as well as
some chlorinated compounds.
The complex dissolved organics have been found to represent
only two percent of the total non-volatile organics. These
are color bodies present in chlorination and caustic
extraction wastes. They are described in NCASI bulletins
(84) (85) reporting on studies conducted at the New York
State University College of Forestry. The color bodies
produced by chlorination were chlorine-containing lignin,
i.e., unsaturated acidic lignin fragments having few of the
aromatic properties of the lignins themselves although
lignin derived. Those color bodies found in caustic extract
were comparatively low molecular weight, chlorine-
substituted acidic materials displaying no aromatic charac-
teristics. It appears then that the chlorination stage
forms color bodies by lignin oxidation and the extraction
stage produces them by chlorine substitution.
Raw waste color data of bleach plant effluents from surveyed
mills have been presented in Table 59. Total raw waste
color data from these mills are shown in Table 62. Total
raw waste color data and final treated effluent data for
surveyed mills are presented in Table 63. Included in the
table are mills in each of the four bleached kraft
224
-------
r.i
en
Table 62
RAW WASTE COLOR DATA FROM SURVEYED MILLS
MILL
CODE
101
117
119
mg/1
843
634
616
COLOR
kg/kkf*
135.5
122
60
(Ib/ton)
(271)
(244)
(120)
Average 106 (212)
-------
TABLE 63
COLOR WASTE LOADS - BLEACHED KRAFT MILLS
Mil 1
101
105
106
no
112
114
116
117
119
125
127
Subcategory
F. Mkt
BCT
F.Mkt
F, Mkt, 6W
F
Mkt
F
BCT-Mkt
F
BCT-GW
D1ss,
FLOW
k1/day(kMl/day)
158.5 (38.0)
162.2 (38.9)
157.2 (37.7)
97.6 (23.4)
110.1 (26.4)
178.9 (42.9)
130.9 (31.4)
205.6 (49.3)
97.2 (23.3)
103.8 (24.9)
229.8 (55.1)
Stream 09
CU kg/kkg (Ibs/ton)
855 135.5 (271)
1500 243 (486)
( - )
1980 193 (386)
( - )
( - )
( - )
593 122 (244)
617 60 (120)
( - )
( - )
Stream 79
CU
805
1110
1760
917
572
1730
580
1070
468
2032
1800
kg/kkg
127.5
180
277
89.5
63
310
76
220
45.5
211
413.5
(Ibs/ton)
(255)
(360)
(554)*
(1»)
(126)
(620)
(152)
(440)
( 91)
(422)*
(827)
Treatment
ASB-PS
ASB-PS
ASB-PS
ASB-C
ASB-C
ASB
ASB
ASB
AS
ASB-PS
ASB
Test
Method
Fisher
Taylor
Helllgi
APHA a
NCASI
Std. Mi
NCASI
Oregon
NCASI
Hellig
Hach Ci
Hellige Comparator pH=7.0
Stream 59
-------
subcategories, and as such considerable ranges of color
values are shown. Differences between raw waste data and
final effluent data indicate a reduction in color across
biological treatment from 10 to 50% which is higher than
previously reported reductions of around 10% (86). This
color reduction may be associated with the apparent color
rather than the true color depending upon the specific color
analytical measurement technique since TSS and turbidity are
being reduced across the biological treatment system. The
color for the final effluent values varies from a low of
45.5 kg/kkg (91.0 Ibs/ton) to a high of 413 kg/kkg (827
Ibs/ton) with a range of color units from 468 to 2032. The
relatively wide range of values reported can be partially
explained by (1) the extent of pulping and bleaching at a
particular mill as indicated by the subcategory and by (2)
the type of analytical procedures used in measuring the
color. The test methods used by the surveyed mills are
shown in Table 63 and the effects, if any, on the color
values reported have not been reconciled at this time. The
highest color values of 413.5 kg/kkg (827 Ibs/ton) in Table
63 is for surveyed mill 127 which a dissolving kraft mill
and should be at the high end of the range due to the
characteristics of the dissolving kraft process; i.e. low
yield, high bleaching. In comparing Tables 59 and 62, it
may be seen that bleach plant color as measured in kg/kkg
(Ib/ton) is only about 25 percent of total raw waste. This
percentage is substantially lower than the 70 to 80 percent
rule-of-thumb figure. The explanation may be in the
difficulty of separating bleach plant flows in order to
obtain representative samples, or in the fact that only
three surveyed mills reported bleach plant effluent color
data.
One undesirable characteristic of bleachery waste water is
foaming. The caustic extraction effluent is primarily
responsible for this propensity which increases if the
caustic and chlorination stage effluents are directly mixed.
The effect is avoided to a considerable degree if the two
streams are mixed with the pulp and paper mill effluents at
different points in the effluent collection system to allow
dilution of the extraction stream before mixing occurs.
However, some foaming cannot be entirely avoided and
measures may need to be taken for its control.
The only kraft bleach plant in the country using oxygen as
one stage is designed so that except during startup it uses
fresh water only for equipment seals, washer and press wire
cleaning showers, and chemical supply (chlorine and chlorine
dioxide water and caustic dilution) (190). This amounts to
about 6.3 kl/kkg (1.5 kgal/ton) of fresh water.
227
-------
Approximately 11.4 kl/kkg (3.0 kgal/ton) of white water are
used for wash water and seal tank make-up (177).
Currently, approximately 378.5-757 1 (100-200 gpm) of the
"O.2" stage effluent which contains highly concentrated BOD5_
losses and color is sent to treatment (177) . The remainder
is used internally to dilute the stock from 28 percent
consistency as it enters the "o^" stage to 12 percent as it
leaves (177) .
There has been limited operating experience with
displacement bleaching since two such systems have been
recently installed. Pilot plant operations indicate that
bleached pulps of market quality can be produced by this
process without washing between stages and that effluent
flow can be reduced to the amount of water introduced with
fresh chemicals (185) .
Development of Subcategory Raw Waste Loads
The development of the raw waste loads (RWL) for the four
bleached kraft subcategories is discussed below. The
resultant raw waste loads were used in developing the
effluent limitations for each subcategory and in determining
the costs presented in Section VIII. Following the
discussion, data for several mills are presented in Table 70
but the data were not used in the development of the
subcategory raw waste loads because of the complexity of the
mills (i.e., several different pulping processes on site,
several types of products manufactured at each mill, and
therefore each mill fit partially into a number of
subcategories) .
Bleached Kraft Dissolving Pulp Subcategory
Each of the three mills in the bleached kraft dissolving
pulp subcategory were surveyed and extensive data were
available for all three mills. Table 64 summarizes the raw
waste characteristics for each mill including mills 108, 510
and 127. Each of the three mills produce some papergrade
quality pulps. The raw waste loads attributable to the
production of papergrade pulp were subtracted from the
actual raw waste loads and thus, the calculated values in
Table 65 represent the raw waste loads which would result
from the production of 100X dissolving grade pulp. The raw
waste flow and BOD5_ values from the bleached kraft market
pulp were used for adjusting the raw waste loads (see
bleached kraft fine papers for adjustment methodology) . The
TSS values in Table 64 were unadjusted (see bleached kraft
fine papers). The calculated values in Table 65 show
228
-------
TABLE
64
RAW WASTE LOAD
BLEACHED KRAFT
DISSOLVING KRAFT SUBCATEGORY
ro
ro
Mill
Production
Flow
BOD5
TSS
kkg/day (tons/day)
108 824 (908)
127** *
510
Average
kl/kkg (kgal/ton)
306
252
131
230
(73.3)
(60.5)
(31.5)
(55.1)
kcj/kkg(lbs/ton)
85.5
37.3
76.0
66.5
(171)
(74.6)
(152)
(133)
mg/L
280
148
578
289
kcf/kk£ ( Ibs/torO
139
87.0
-
113
(277)
(174)
( - )
(226)
mg/L
549
379
-
492
Confidential
**Based upon 100% dissolving
-------
TABLE 65
RAW WASTE CHARACTERISTICS
BLEACHED KRAFT: DISSOLVING PULP MILLS
Flow BOD^ TSS % Dissolving
Mill k1/kkg(kg1/ton) kg/kkg(1bs/ton) kg/kkg(1bs/ton) Pulp Production
103
127
510
252 (60.6)
234 (56.1)
131 (31.5)
ACTUAL
61.0 (122.0)
33.1 ( 66.1)
104.0 (208.0)*
139.0 (277)
87.0 (174)
- ( - )
60
75
74
*includes prehydrolysate
CALCULATED
108 306 (73.3) 85.5 (171.0) 139.0 (277)
127 252 (60.5) 37.3 ( 74.6) 87.0 (174)
510 131 (31.5) 76.0 (152.0) - ( - )
Average 230 (55.1) 66.5 (133.0) 113.0 (226)
230
-------
differences in flow and BOD5 between the mills but
examination of the manufacturing processes and the in-plant
controls at the mills do not explain the differences. The
differences in the BOD5_ RWL may possibly be attributable to
the differences in in-plant control measures used for
disposal of prehydrolysate. It should be pointed out that
two of the three mills presently evaporate and burn the
prehydrolysate, and the third mill (mill 510) is planning to
install a similar system in the near future. The RWL BOD5_
of 104 kg/kkg (208 Ibs/ton) in Table 65 for mill 510
includes sewering of the prehydrolysate.
The mill management expects that the present BOD5_ RWL will
be reduced by approximately 40% when the prehydrolysate is
no longer discharged along with the process waste waters.
The calculated values in Table 65 take this into account
with an allowance for 5% return of BOD^ as condensate. As
shown in Table 64, the average RWL for the bleached kraft
dissolving pulp subcategory are the following:
Flow: 230 kl/kkg (55.1 kgal/ton)
BOD5: 66.5 kg/kkg (133 Ibs/ton)
TSS: 113 kg/kkg (226 Ibs/ton)
Bleached Kraft Market Pulp Subcategory
The data from surveyed mills in the bleached kraft market
pulp subcategory are summarized in Table 66. The mills in
Table 66 represent market pulp mills in all sectors of the
country. The mills were built during the 1960's (except
mill 130:1953) and no significant correlation between RWL
and the age of mills exists. The size of the mills ranged
from around 272 kkg (300 tons) to nearly 907 (1000 tons) of
pulp per day with no significant correlation between size
and RWL. Each of the mills produces exclusively highly
bleached market pulp by similar manufacturing operations.
The differences in BOD5_ RWL, TSS RWL, and effluent volumes
between mills in Table 66 is primarily attributed to the
extent of internal pollution control measures in use by each
mill as discussed in Section VII.
As shown in Table 66, the average RWL for the bleached kraft
market pulp subcategory are the following:
Flow: 173 kl/kkg (41.6 kgal/ton)
BOD5: 38.0 kg/kkg (75.9 Ibs/ton)
TSS 45.0 kg/kkg (90 Ibs/ton)
Data were available for seven of the eight mills in the
bleached kraft market pulp subcategory; however, data from
231
-------
TABLE 66
raw msTE i/cmo
BLEACHED KRAFT
PUIP SUBCMBGORY
Mill
Production
Flow
BODs
TSS
ro
co
IV)
kkg/day (tons/day)
126
114
139
130
185
186**
140***
Average
480
641
883
366
610
544
288
(529)
(707)
(973)
(404)
(673)
(600)
(318)
kl/kkg (kgal/ton)
180
176
85.1
284
143
188
78.8
173
(43.1)
(42.3)
(20.4)
(68.2)
(34.2)
(45.0)
(18.9)
(41.6)
kg/kkg(lbs/ton)
28.0
46.5
40.7
41.7
32.4
37.5
27.7
38.0
(56.0)
(93.0)
(82.4)*
(83.4)
(64.7)
(75.0)
(55.4)*
(75.9)
mg/L
156
264
478
147
227
200
351
219
kg/kkg ( Ibs/ton) mg/
22.5
15.7
70
72.5
-
-
72.5
45.0
(45.0)
(31.3)
(140)
(145)
( -)
( -)
(145)
(90)
125
89
823
254
-
-
920
259
* Calculated using 15% BOD removal by primary treatment.
** Not included in subcategory average (insufficient data).
*** Not included in subcategory average (see text).
-------
mills 186 and 140 were not included in the overall
subcategory average. The data for mill 186 were
insufficient relative to the extensive amount of data for
the other mills, and the data for mill 140 showed both flow
and BOD5 values which were significantly lower than other
mills in Table 66. It should be pointed out that inclusion
of both mill 186 and mill 140 would have resulted in a
subcategory RWL which is less than that determined (Flow:
161 kl/kkg (38.5 kgal/ton) , BOD5: 37.8 kg/kkg (75.6
Ibs/ton) ) . The TSS data from mill 140 was used in
determining the TSS RWL because TSS RWL data for mills 126,
114, and 185 were unavailable and TSS measurements at mill
130 were conducted using non-standard analytical techniques
(TSSN) .
Bleached Kraft BCT Papers Subcategory
Raw waste characteristics for mills producing bleached kraft
BCT papers and for mills producing BCT papers and market
pulp are summarized in Table 67. As shown in the table, the
average RWL for the bleached kraft BCT papers subcategory
are the following:
Flow: 148 kl/kkg (35.4 kgal/ton)
BODS: 38.4 kg/kkg (76.7 Ibs/ton)
TSS: 66.5 kg/kkg (133 Ibs/ton)
Bleached Kraft Fine Papers
Table 68 presents raw waste load data for bleached kraft
mills producing fine papers and for mills producing fine
papers and market pulp. The size of the mills included in
the table range from less than 181.4 kkg/day (200 tons/day)
to more than 1451 kkg/day (1600 tons/day) and no significant
correlation between raw waste load and size exists. The age
of the mills in the table varies from 1864 to 1970; mill
119, built in 1864, has a lower raw waste load than mill
112, built in 1969, which demonstrates that old mills can
reduce raw waste loads to equivalent or better than new
mills through upgrading of equipment and installation of
inplant control technologies. As more fully discussed in
Section IV, relationships between age of mill and raw waste
load generally do not exist. Approximately half of the
mills in the table produce some market pulp in addition to
fine papers, and several mills purchase pulp as a
supplementary source of fiber. Mills 120 and 110 produce
some groundwood pulp in addition to bleached kraft and mill
136 produces approximately 40% BCT papers. Mill 116
produces 100% fine papers but uses both purchased pulp and
waste paper as supplementary fiber sources. These
233
-------
TABLE 67
RAW WASTE LOAD
BLEACHED KRAFT
BCT PAPERS AND MARKET PULP MILLS
Mill
105
109
ro 111
OJ
121
113
122
100
138
131
Average
Production
kkg/day(tons/day)
1017 (1121)
996 (1098)
667
1214
( 735)
(1338)
1055 (1163)
540 ( 595)
931 (1027)
( 996)
( 791)
903
717
Flow
kl/kkg (kgal/ton)
162 (38.9)
167
138
158
139
123
152
131
159
148
(40.0)
(33.1)
(37.9)
(33.3)
(29.5)
(36.5)
(31.3)
(38.1)
(35.4)
BOD 5
kg/kkg(Lbs/ton)
36.4 (72.7)
35.6
29.5
29.9
37.0
45.2
44.5
49.0
-
38.4
(71.2)
(58.9)
(59.8)*
(74.0)
(90.3)
(89.0)
(98.0)*
(- )
(76.7)
mg/L
224
213
213
189
266
367
293
375
-
260
TSS
kg/kkg(lbs/ton)
128 (255)
54.0 (108)
- ( - )
- ( - )
52.0 (104)
31.6 (63.2)
- ( -)
- ( - )
66.5 (133)
Products %
mg/L BCT Market
100
764 100
392 100
90
70
507 70
208 80
80
80
450
0
0
0
10
30
30
20
20
20
Calculated using 15% BOD5 removal by primary treatment.
-------
TABLE 68
RAW WASTE LOAD
BLEACHED KPAFT
FINE PAPERS & MARKET PULP MILLS
Mill
116
118
134
119
132
112
ro
OJ
^ 136
103
135
106
101
107
110
120
Average
Production
kkg/day (tons/day)
1043 (1150)*
174
857
521
378
580
1497
385
585
486
516
255
1015
1052
( 192)
( 945)
( 575)
( 417)
( 640)
(1650)
( 425)
( 645)
( 536)
( 569)
( 281)
(1119)***
(1160)****
Flow
kl/kkg(kgal/ton)
140 (33.5)
125
93
89
81
110
120
168
169
160
152
154
100
130
125
(30.0)
(22.3)
(21.3)
(19.5)
(26.4)
(28.7)
(40.2)
(40.6)
(38.4)
(36.4)
(27.0)
(24.0)
(31.2)
(30.0)
BOD5
kg/kkg(lbs/ton)
49.7 (99.4)
20.3
30.9
21.2
23.5
24.7
29.0
37.5
37.2
34.5
26.1
40.8
27.7
48.0
32.3
(40.6)
(61.7)
(42.4)
(47.0)
( 49.4)
( 58.0)
( 74.9)
( 74.4)
( 69.0)
( 52.2)
( 81.6)
( 55.4)
( 96.0)
( 64.6)
356
189
322
239
289
224
242
223
221
215
182
264
277
369
258
TSS
kg/kkg(lbs/ton)
220 (439)
-
82.5
43.3
128.0
78.5
69.5
70.0
44.7
52.5
-
58.0
124.0
90.0
( -)
(165.0)
( 86.6)
(256.0)
(157.0)
(139. 0)N
(140)
( 89.3)
(105)
-
(116.0)
(248.0)
(180)
P
mg/L
1571
-
887
488
1570
656
384
413
279
344
-
580
953
719
urchased
Pulp %
50
0
20
0
50
25
12
0
0
0
0
10
10***
0**
Product %
Fine Market
100
100
100
100
100
100
95**
50
60
45
55
75
70
65
0
0
0
0
0
0
5
50
40
55
45
25
30
35
* 30% purchased pulp, 20% waste paper
** 55% fine papers, 40% BCT
*** ln* of production by groundwood
**** 5% of production by groundwood
N
Non-standard methods TSS analytical measurement technique.
-------
differences in production processes, sources of fiber, and
type of product can have impacts upon the raw waste load
discharged by each mill.
In determining the bleached kraft fine papers subcategory
raw waste load, the mill raw waste loads were adjusted to
simulate production of 100X fine papers from pulp
manufactured on-site. The differences in production, fiber
sources, and final products were taken into account where
relatively accurate adjustment factors were available and
where the differences were considered to have significant
impacts on the raw waste load. In several cases, there were
multiple factors which overly complexed the adjustment
process and these mills were not included in the subcategory
average.
The methodology used to adjust those mills using purchased
pulp as a supplementary fiber sources is discussed below and
used the following factors in adjusting for purchased pulp:
Flow: 63.4 kl/kkg (15.2 kgal/ton)
BODS: 10.75 kg/kkg (21.5 Ibs/ton)
These factors were derived from the non-integrated fine
papers subcategory raw waste load as shown in Table 68. In
addition, adjustments to the RWL for mills 110 and 120 were
made for the contribution of the groundwood pulping
operations at those two mills. The factors used are shown
below and were derived from the flow and BODS RWL for the
groundwood: fine papers subcategory.
Flow: 91.3 kl/kkg (21.9 k gal/ton)
BODS: 16.7 kg/kkg (33.3 Ibs/ton)
No adjustments were made for TSS because significant
correlations between TSS raw waste loads and production
processes do not exist as a general rule due to the internal
practices on fiber control in use by pulp and paper mills.
In any event, the primary pollutant factors in the raw waste
load which are of concern in the development of the raw
waste loads are flow and BODji. The flow and BOD5_ values
have a direct impact upon the effluent limitations whereas
the TSS in the raw waste from pulp and paper mills are
generally removed by primary treatment. The TSS in final
effluents from adequately designed and operated systems
which are preceded by adequate primary treatment are more
related to the raw waste BOD5_ than to the raw waste TSS.
The TSS raw waste loads were primarily used in the
development of the costs presented in Section VIII.
236
-------
Two sample calculations are presented below for mills
and 110 to demonstrate the use of the purchased pulp and
groundwood factors, respectively. It should be noted that
all calculations presented below are in metric units of
kl/kkg for flow and BOD5 values, respectively.
A = B - X C
Y
A = Flow or BOD5_ representing on-site production of
100% of pulp into paper
B = Flow or BOD5_: Actual mill values
C = Flow or BODf>: Purchased Pulp Factors
X = Percentage of purchased pulp
y = Percentage of on-site manufactured pulp
Mill 13
-------
Adjust flow for Groundwood:
A. = 104- (0.1) (91.3) = 105.5 kl/kkg
0.9
Adjust BODS for Purchased Pulp:
A = 27.7- (0.1) (10.75) = 29.6
0.9
Adjust BODS for Groundwood:
A = 29.6- (0.1) (16.65) = 31.05 kg/kkg
0.9
Table 69 presents the adjusted raw waste loads for bleached
kraft mills which represent the production of fine papers
and market pulp from 100% on-site bleached kraft
manufactured pulp. The TSS raw waste loads are the actual
values for each mill as discussed previously. As shown in
the table, the average raw waste load for the bleached kraft
fine papers subcategory are as follows:
Flow: 129 kl/kkg (30.9 kgal/ton)
BOD5: 33.6 kg/kkg (67.2 Ibs/ton)
TSS: 75.5 kg/kkg (151 Ibs/ton)
SODA SUBCATEGORY
Approximately 83.5 to 125 kl/kkg (20.0 to 30.0 kgal/ton) of
effluent are generated in soda pulping, the specific volume
depending largely on cooling requirements. Reuse of paper
machine water in the pulp mill is limited by the fillers
used in the manufacture of printing papers from soda pulp
which render this water unsuitable unless it is clarified to
a high degree.
There are four major effluent streams from the pulp
production process: the decker seal pit water, the digester
relief condensates, the bleach plant effluent, and the
recovery plant discharge which includes miscellaneous waste
waters such as boiler plant and water treatment plant
effluents. In Figure U2, the first two flows are combined
into the "pulp mill" flow, since waste data are not
available for the individual streams. The major pollutional
characteristics of the combined effluents are suspended
solids, BODji, and color. The suspended solids, fiber fines,
and debris are mostly settleable and are more than 90 per-
cent combustible (5) . Normal BOD5_ and TSS values range from
238
-------
TABLE 69
RAW WASTE LOAD
BLEACHED KRAFT
FINE PAPERS SUBCATEGORY
Production
Mill kkg/day(tons/day)
r\>
CO
118
134
1X9
132
112
103
135
106
101
107
110
174
686
521
190
435
385
585
486
516
229
812*
( 192)
( 756)
( 575)
( 209)
( 480)
( 425)
( 645)
( 536)
( 569)
( 253)
( 895)
Flow
kl/kkg(kgal/ton)
120
Average
999
(1102)
**
125
100
89
81
126
168
169
160
152
118
106
132
(30.0)
(24.1)
(21.3)
(23.8)
(30.1)
(40.2)
(40.6)
(38.4)
(36.4)
(28.3)
(25.3)
(31.7)
129
(30.9)
BOD5
kg/kkg (Ibs/ton) mg/L
33.6 (67.2)
TSS
kg/kkg (Ibs/ton) nxj/L
20.3
35.9
21.2
36.3
29.3
37.5
37.2
34.5
26.1
44.2
31.1
49.7
(40.6)
(71.8)
(42.4)
(72.5)
(58.7)
(74.9)
(74.4)
(69.0)
(52.2)
(88.3)
(62.1)
(99.3)
189
357
239
365
-
223
221
215
182
374
294
376
—
82.5
43.3
128.0
-
69.5
70.0
44.7
52.5
-
58.0
124.0
_
(165.0)
( 86.6)
(256.0)
-
(139. 0)N
(140.0)
( 89.3)
(105.0)
-
(116.0)
(248.0)
^
821
488
1290
-
384
413
279
344
-
550
938
261
75.5 (151.0)
586
*10% of production by groundwood
**5% of production by groundwood
-------
TABLE 70
RAW WASTE LOAD
BLEACHED KRAFT MTT.Tfi
MULTIPLE SUBCATEGORY MILLS
-C.
o
Mill
104
125
501
102
166
110
Production
kkg/day ( tons/day)
1196 (1319)
1243
1256
925
1029
1015
(1370)
(1385)
(1020)
(1135)
( 119)
Flow
kl/kkg(kgal/ton)
219 (52.5)
104
199
142
126
100
(24.9)
(47.7)
(33.0)
(30.2)
(24.0)
BODS
kg/kkg (Ibs/ton)
40.1 (80.2)
28.4 (56.7)
- <-,
21.3 (42.5)
30.1 (60.2)
27.7 (55.4)
116
1043 (1150)
131 (31.4)
56.0 (112)
182
273
428
TSS Remarks
kg/kkg(Ihs/ton) mg/L
55.0 (-)
- (-)
45.7 (91.4)
62.0 (124)
58.0 (116)
198 (395)
Fine Papers & BCT
Papers
BK & Groundwood, BCT
Papers
Market Pulp & BCT
Papers
322 BK & Groundwood, BCT
Papers
494 BK, UK, Groundwood,
Fine and BCT Papers
580 BK & Groundwood,
Market Pulp & Fine
Papers
1508 BK & Waste Papers,
Fine Papers
-------
FIGURE 42
EFFLUENT CHARACTERISTICS: SODA MILL
PROCESS
WATER
PULP MILL
13,000 GAL/TON
29 LB BOD5/TON
49 LB TSS/TON
9.3pH
LIQUOR RECOVERY
2,000 GAL/TON
8 LB BOD5/TON
31 LB TSS/TON
9.9 pH
BLEACH PLANT
7,500 GAL/TON
29 LB BOD5/TON
7 LB TSS/TON
6.3 pH
PAPER MILL
7,500 GAL/TON
30 LB BOD5/TON
68 LB TSS/TON
5.7pH
RAW
WASTE
30,000 GAL/TON
96 LB BOD5/TON
155 LB TSS/TON
8.2 pH
241
-------
200 to 300 mg/1 or about 20 to 30 kg (HO to 60 Ib) per kkg
(ton) of pulp produced. BOD5_ values are in the same range.
Color ranges from 800 to 1500 mg/1 during periods of normal
operation.
Soda pulping effluents contain some components inimical to
aquatic life (50). These are resin acid soaps and turpene
derivatives. Since sulfur is not used in the process, the
effluent appears to have a slightly lower toxicity level
than kraft. However, like kraft effluents it can give rise
to foaming.
Soda pulp bleaching effluents are similar to those of kraft
and contain 10 to 20 kg (20 to HO Ib) of BOD5> per kkg (ton)
of pulp bleached (See Figure 42). The volume ranges between
50.1 to 75.1 kl/kkg (12.0 to 18.0 kgal/ton). Color of these
effluents will vary with the species of wood from which the
pulp was produced.
The above data cited from literature sources for soda
pulping operations tends to be somewhat higher than more
recent data obtained from the surveyed mills which reflects
the efforts in recent years to reduce pollution loads.
Figure U2 is presented as an example of a soda pulp and
paper mill with the effluent characteristics shown in order
to show the relative contributions of the unit process
operations to the total raw waste load.
Development of Soda Subcategory Raw waste Loads
The development of the raw waste loads (RWL) for the soda
subcategory is discussed below. The resultant raw waste
loads were used in developing the effluent limitations for
the soda subcategory and in determining the costs presented
in Section VIII.
The surveyed soda mills are old, but have been modernized
since 1965. All make fine papers from various percentages
of purchased pulp and of soda pulp manufactured on-site.
Since the on-site surveys of the soda mills, one of the
mills, mill 150, has shut down operations and therefore.
Table 71 only presents raw waste loads for the other two
soda mills. Both of the mills use purchased pulp as a
supplementary source of fiber in producing fine papers. As
in the bleached kraft fine papers sutcategory, the raw waste
loads were adjusted to simulate the production of fine
papers from pulp manufactured on-site. The methodology used
to adjust the actual raw waste loads was discussed
previously in the development of the bleached kraft fine
242
-------
TABLE 71
RAW WASTE IDAD
SODA SUBCATEGORY
Actual
Mill
151
152
Mill
151
152
Production
kkg/day (tons/day)
634 (699)
553 (610)
Average
Flow
kl/kkg(kgal/ton)
118 (28.2)
170 (40.7)
Average 144 (34.5)
Flow
kl/kkg (kgal/ton)
108 (26.0)
111 (26.6)
110 (26.3)
BODS
kg/kkg (Ibs/ton)
52.5 (105)
34.0 (68.0)
43.3 (86.5)
BODS TSS Purchased
kg/kkg (Ibs/ton) mg/L kg/kkg (Ibs/ton) mg/L Pulp %
47.7 (95.3) 439 - - 12
23.3 (46.6) 210 143 (285) 1290 46
35.5 (71.0) 324 143 (285) 1299
Calculated
TSS
mg/L kg/kkg (Ibs/torj mg/L
446 - ( - )
200 143 (285)* 1290*
301 143 (285) 991
*TSS is actual value
-------
papers subcategory raw waste loads. Table 71 shows the
actual mill raw waste load data and the calculated raw waste
load data. The resultant average soda subcategory raw waste
loads are the following:
Flow: 142 kl/kkg (34.1 kgal/ton)
BOD5: 43.3 kg/kkg (86.5 Ibs/ton)
TSS: 143 kg/kkg (285 Ibs/ton)
DEINK SUBCATEGORY
The major sources of effluent from the deinking process are
the washers and centri-cleaners; the remaining streams
consist mainly of miscellaneous white water overflows,
floor drainage, washup, and cooling waters. In older
operations deinking fine papers, the total effluent ranged
between 62.6 and 104 kl (15.0 and 25.0 kgal) per kkg (ton)
of waste paper processed depending upon the quality of the
product produced and equipment used. More recent data from
surveyed mills indicates that several mills have
substantially reduced their flows in recent years. Mills
217 and 204 which manufacture fine papers and mills 213 and
215 which manufacture tissue papers all have flows of about
50.0 to 54.2 kl/kkg (12.0 to 13.0 kgal/ton). Approximately
41.7 kl (10.0 kgal) of water are required per kkg (ton) of
newsprint deinked (6). In decoating operations producing a
crude pulp for use in board products, the wash water is
sometimes settled and reused; cutting the total discharge to
under 20.9 kl (5.0 kgal) per kkg (ton) of waste paper
processed.
Clarified white water from papermaking operations may supply
a considerable portion of the water used for washing and
cleaning. The entire waste water flow from a single-stage
bleaching operation can also be used in deinking for
dilution and preliminary wash water. However, effluent
discharged from three stage bleacheries, 50.1 to 83.5 kl
(12.0 to 20.0 kgal) per kkg (ton) of pulp bleached, is not
generally suitable for reuse because of its color.
The major polluting characteristics of deinking effluents
are BOD5_ and suspended solids, both settlcable and dispersed
(88) (89). Organics present include adhesives, products of
hydrolysis and fiber lost in the process. Inorganics derive
from mineral fillers, ink pigments, and other materials
separated from the fiber in waste paper as well as chemicals
used in the process. Included in the latter are dissolved
electrolytes and detergents which add to the total solids
and foaming propensities of receiving waters.
244
-------
The electrolytes are primarily sodium salts. Up to 30 kkg
(60 Ibs) of these salts as Na+ are added to the cooking
liquor per kg/Jckg (ton) of waste paper processed and most
appear in the effluent. Cooking also contributes other
inorganics present in the waste paper such as aluminum
hydrate.
Sodium silicate used as a cooking liquor component will
account for the presence of silica in the effluent and
calcium can be present as a product of calcium hypochlorite
bleaching. Bleaching may also contribute some chloride ion.
Color can be a factor in deinking and attendant bleaching
operations although it is a minor one in comparison to the
color values which result from the manufacture and bleaching
of chemical pulps. Extensive data for color of deinking
wastes are not available.
Table 72 gives a range of values for the solids and BOD5_
content of total deinking waste, including bleaching. This
data is not directly comparable to the surveyed mill data,
since the former is based upon kkg (tons) of waste paper
handled, while the latter is based upon kkg (tons) of paper
produced. Table 72 indicates that BOD5 and TSS appear to be
in the neighborhood of 50 kg/kkg (100 Ib/ton) and 150 kg/kkg
(300 Ib/ton), respectively, on the basis of weight of waste
paper handled. These high losses can be expected when
considering the shrinkage data obtained from surveyed mills.
Shrinkage is the percent loss of weight of waste paper in
the deinking process. This loss appears in the waste water
primarily as BOD5_ and TSS. As shown in Table 73, shrinkage
values range from 18 to 25 percent.
Figure 43 is presented as an example of a deink mill with
the final effluent characteristics shown in order to show
the relative contributions of the deink mill and the paper
mill to the total raw waste load.
Development of Deink Subcategory Raw Waste Load
The development of the raw waste loads (RWL) for the deink
subcategory is discussed below. The resultant raw waste
loads were used in developing the effluent limitations and
costs presented in Sections VIII and IX.
The raw waste load data for mills in the deink subcategory
are summarized in Table 74. As shown, data were available
for 12 of the approximately 17 mills in the subcategory. As
discussed in Section IV, consideration was given to
establishing two subcategories for the deink mills and as
such, Table 74 is divided into two groups of mills. The
245
-------
Table 72
SOLIDS AND BODS LOADING FROM
DEINKING MILL OPERATIONS
(Based on Waste Paper Handled)
PO
JS,
CD
Effluent
Volume
1000 1/kkg
(1000 gal/ton)
117
(28)
104
(25)
125
(30)
71
(17)
50
(12)
88
(21)
TSS
#/ton
100
(200;
250
(500)
225
(450)
195
(390)
300
(600)
380
(760)
BODS
///ton
39
(78)
4*?. 5
(95)
50
(100)
37.5
<>3)
40
(80)
57.5
(115)
-------
Table 73
Deink Mill Shrinkage
PERCENT
MILL SHRINKAGE
203 2.3
204 21
207 18
208 20
-------
FIGURE 43
EFFLUENT CHARACTERISTICS: DEINK MILL
PROCESS
WATER
DEINK
MILL
PAPER MILL
I
11,000 GAL/TON
71 LB BOD5/TON
180 LB TSS/TON
!0.5pH
9,000 GAL/TON
4 LB BOD5/TON
80 LB TSS/TON
8.9pH
RAW
WASTE
20,000 GAL/TON
75 LB BODg/TON
260 LB TSS/TON
9.3 pH
-------
TABLE 74
RAW WASTE LOAD
DEINK MILLS
Mill Manufactured (%) Products
D PP WP C&F
Production
kkg/day(tons/day)
Flow
kl/kkg (kgal/ton)
BODS TSS
kg/kkg (Ibs/ton) rog/L kg/kkg (Ibs/ton) mg/L
203 35
217 75
204 25
210 25
207 15
Average
212 100
214 100
206 100
216 60
213 50
215 25
211 3
Average
Average
33
0
50
50
70
0
0
0
20
0
10
0
(all
12
0
5
5
0
0
0
0
20
50
65
67
mills)
20
25
20
20
15
0
0
0
0
0
0
0
F
F
F
F
F
T
T
T
T
T
T
T
349
293
181
291
245
82
44
717
72
30
120
70
(385)
(323)
(200)
(321)
(270)
( 90)
( 48)
(790)
( 79)
( 33)
(132)
( 77)
75.1
55.0
55.5
80.1
162.6
85.5
100.5
140.7
87.2
106.3
50.4
52.9
127.2
96.3
91.7
(18.0)
(13.2)
(13.3)
(19.2)
(39.0)
(20.5)
(24.1)
(35.9)
(20.9)
(25.5)
(12.1)
(12.7)
(30.5)
(23.1)
(22.0)
53.5
91.5
27.5
34.7
-
5
92.5
-
63.5
72.5
16.8
62
61.5
57
(107)
(183)
( 55)
(69.4)
( - )
(104)
(185)
( - )
(127)
(145)
( - )
(33.6)
(124)
(123)
(114)
713
1662
496
433
-
826
920
-
729
682
-
317
487
638
621
155
194.5
99.5
92
89
147
296.5
-
162
253
-
55.5
144
208
172
(310)
(389)
(199)N
(184)
(178)N
(294)
(593)
( - )
(324)
(506)
(-_
(lll)N
(288)N
(415)
(343)
2065
3534
1794
1149
547
2136
2950
-
1859
2379
-
1132
1132
2154
1869
-------
mills manufacturing fine (F) papers are shown in the top
group and those manufacturing tissues (T) papers are shown
in the lower group. Also, shown in the table is
manufacturing information including the percentage of the
total product as made up by purchased pulp, waste paper (not
deinked), deinked waste papers, and clays and fillers (C6F).
As shown in the table, the average RWLs for deink mills
producing fine papers are less than for mills producing
tissue papers. However, it was determined that the
establishment of one subcategory was appropriate and that
the subcategory RWL should be based upon mills which deink
100% of the pulp, namely mills 206, 212, 214, and 217.
Clays and fillers are not considered to add substantially to
the flow, and therefore the flow for mill 217 was based upon
clays and fillers not being included in the production. As
shown on Table 75, averaging the FWL for those mills
resulted in the following subcategory FWL:
Flow: 102 kl/kkg (24.4 kgal/ton)
BOD5: 90.0 kg/kkg (180 Ibs/ton)
TSS: 202.5 kg/kkg (405 Ibs/ton)
These values are higher than the average for all mills shown
in Table 74 and were used due to the nature of the deinking
process (i.e., deinking is basically a cleaning process and
as such the type of waste paper used as the fiber source has
significant effects upon the effluent characteristics;
changes in market conditions have direct effects upon the
availability and use of the type of waste paper and thus use
of a conservative RWL was determined more appropriate than
using the direct average of all mills).
PAPERMAKING
As used in this discussion, the term "papermaking" includes
stock preparation as well as the forming, drying, and
ancillary processes which occur on the paper machine itself.
Paperboard is made on similar equipment within all
subcategories with similar water uses and similar sources of
waste water. Therefore, papermaking for all subcategories
is discussed together, but attention will be drawn to
significant differences among the sufccategories.
Water Use and Reuse
Water is used for a wide variety of purposes in papermaking.
Definitive data on quantities used are lacking for two
principal reasons. First, there has been an increasing
trend toward reuse within the industry involving the
250
-------
TKBLE 75
RAW WASTE LOAD
DEINK SUBCATEGCKy
Mill Production Flow BODs
kkg/day (tons/day) kl/kkg (kgal/ton) kg/kkg (Ibs/ton) mg/L
TSS
kg/kkg(Ibs/ton) mg/L
217*
212
214
206
366
82
44
717
(404)
( 90)
( 48)
(790)
68.8
100.5
140.7
87.2
(16.5)
(24.1)
(35.9)
(20.9)
114
925
-
63.5
(229)
(185)
(127)
1662
920
-
729
243
296.5
162
(486)
(593) N
-
(324)
3534
2950
-
1859
Average
101.7 (24.4)
* Adjusted for 25% C & F (See text)
251
-------
transport of waste water from one subprocess for use in one
or more different subprocesses. For example, machine white
water is used for consistency regulator dilution in both the
stock preparation and papermaking areas. Reuse quantities
are rarely metered separately. Second, the complexity of
the subprocesses and their interconnections, together with
the many individual use points of fresh water, makes it
almost impossible to meter each usage of fresh water. The
overall effect of reuse, however, is to reduce the quantity
of fresh water, and hence the quantity of waste water
leaving the entire process. This effect is discussed later
in this section.
Because of the limited amounts of published data, estimates
have been made of individual usages of water based upon
general engineering design values and upon information
obtained at surveyed mills. The use points and their
estimated flows are shown in Table 76. It must be
emphasized that these are gross values, including, in most
cases, substantial reuse. Therefore, as discussed below,
the sum of individual uses will exceed the total fresh water
usage by a substantial amount.
The extent of reuse depends on many factors including
product requirements, manufacturing demands, length of
production run, and engineering considerations. Every
surveyed mill engaged in papermaking reuses water in the
process to some extent, and most of them reported continuing
programs to reuse more. All of them reuse furnish dilution
water which is the largest use shown in Table 76. Because
considerable effort has been made by some mills to minimize
fresh water use for cleaning of fourdrinier wires, estimates
of this use and reuse were obtained from some surveyed mills
and are shown separately in Table 77. Further discussion of
these results is deferred to Section VII.
Wastewater Characteristics
In a papermaking area, the principal waste water discharges
are as follows:
1. Excess white water from seal pits or other tank
overflows
2. Rejects from stock cleaning devices (centrifugal
cleaners, screens, and junk traps)
3. Felt and wire cleaning waters
252
-------
Table 76
ESTIMATED WATER USAGE FOR PAPERMAKING
Use
Flow, gal/ton
ro
en
CO
1. To fiberize stock and convey it from one subprou^ss to another
2. To clean equipment such as wires, cylinder molds, and felts during pro-
duction, and to knock down foam
3. To "hydrate" and/or cut the fibers to provide proper strength and fiber
length
4. To dilute the furnish for cleaning, forming, :nd for consistency regulation
5. To dissolve, disperse, dilute, and/or convey additives alum, starch, and
fillers
6. To lubricate and seal moving parts such as shafts and vacuum pumps
7. To provide steam for processing and space heating (net)
8. To cool equipment and process fluids
9. To wash up equipment and adjacent floor areas after production runs
6000
See Table 26
Included
in 1
50,000
0-2000
2000-6000
500
2000-10,000
500-2000
-------
Table 77
ESTIMATED WATER USA"F, FOR u'CURDKI.NIER SHOWERS
SUBCATEGORY
Groundwocd
Sulfite
Bleached Kraft
Soda
Deink
Non-Integrated
Fine Papers
Non-Integrated
Tissue Papers
Non-Integrated
Coarse Papers
MILL
COD::
00"
012
013
014
050
053
056
105
124
125
126
151
205
207
250
252
257
261
262
265
267
300
305
309
310
312
351
353
THOUSAND GALLONS PER TON
V.11ITE WATER
2.0
(some)
3.9
1.8
0.5
1.0
6.8
5.8
4.3
3.0
5.0
5.4
FRESH WATER
3.2
0.8
1 3
2.7
2.2
32
10
2.6
2.2
1.8
0.4
7.2
1.2
0.2
4.3
1.0
6.8
12
90
6.3
(some)
14
TOTAL
3.?
2.8
1.3+
2.7
2.2
32
10
6.5
2.2
3.6
0.5
1.4
14
5.5
1.2
6.0
8.6
2.7
1.0
9.8
12
10
90
18
6.3
5.0+
5.4
14
254
-------
4. Spills, washups, discharge of tank dregs, and
other non-equilibrium losses
5. Cooling water discharges
6. Boiler blowdown and other miscellaneous discharges.
Sources of BOD5 in waste waters are the organic raw
materials used as the constituents of paper. Cellulose is
foremost, comprising 80 percent or more of the weight of
most papers. Rosin sizings and starch or protein adhesives
also contribute to BODS^ loadings, as do many special organic
chemicals such as wet strength resins. Some or all of these
constituents, including cellulose fibers, are in the solid
or precipitated state, and therefore also contribute to TSS
loadings. Fillers and coating pigments such as clay and
titanium dioxide are responsible for virtually no BOD!5, but
add to TSS loadings.
Most losses from papermaking are undesirable from the
economic as well as the pollution viewpoint, since they are
valuable materials which could otherwise be incorporated in
the sheet and sold. Data breakdowns on principal losses as
listed above are not available because of sewer
interconnections and reuse complications. Each item is
discussed below, with estimates of such losses where
available.
Excess white water results from necessary additions of fresh
water to the process system. While measures are available
to reduce these losses by means of savealls, as discussed in
Section VII, some material inevitably escapes to sewer. The
saveall effluent contains some remaining TSS, and may have
significant BODji since the saveall cannot remove dissolved
BOD^. Centrifugal cleaner rejects are reduced to approxi-
mately 0.1-1.0 percent of production, but nevertheless
represent a significant source of TSS loss. Rejects also
contain significant BOD5^ Felt and wire cleaning waters are
frequently diverted to sewer, and usually contain only minor
loadings of TSS and BODjj.
Non-equilibrium losses can be very significant. Generally,
one-quarter to one-half of total paper mill BODji and TSS
loadings are due to these losses which are related to
production upsets due to machine startups, shutdowns, and
washups, dumping of tank remnants at end of runs, electrical
and steam outages, and equipment failure. Because of inter-
connected sewers, data breakdowns within the above list are
not available.
255
-------
A special effort was made at surveyed mills to obtain
estimates of nonequilibrium losses, since these may have a
significant surge impact upon treatment facilities. Few
data were available, however. Those obtained are shown in
Table 78.
Water is used to cool condensate from paper machine steam-
heated dryers. This use may account for 8.3 to 16.6 cu. m
per kkg (2000 to 4000 gal/ton). In addition, water is used
to cool gear boxes, brake drums, lubricating oil systems,
bearings, and other miscellaneous equipment. Mills which
generate electricity from steam may use large volumes of
water for condenser cooling. These are normally discharged
separately and not admitted to process sewers or treatment
facilities. Normally fresh water is used for cooling to
minimize fouling problems on heat exchangers and because it
is the lowest temperature water available. Several mills
collect the major cooling water effluents to supplement
fresh water process needs. Cooling waters rarely contain
significant loadings of BOD5 or TSS.
Boiler blowdowns and other miscellaneous discharges also
rarely contain significant amounts of BODJ3 and TSS.
Phosphates used in boiler water treatment and discharged in
the blowdowns are beneficial to biological treatment systems
as a partial source of phosphorus nutrient. Data for
papermaking operations of mills surveyed in integrated
pulping subcategories have been presented above. It is
probably that these losses are not completely
representative, however, since some pulp mill losses may be
included. On the other hand, some papermaking white waters
may be returned to the pulp mill and therefore not be
represented as papermaking losses.
Development of Non-Integrated Subcategory Raw Waste Loads
The development of the raw waste loads (RWL) for the non-
integrated paper mill subcategories is discussed below. The
resultant raw waste loads were used in developing effluent
limitations for each subcategory and in determining the
costs presented in Section VIII.
Non-Integrated Fine Papers Subcategory
The raw waste loads of the surveyed non-integrated fine
paper mills are shown in Table 79. The mills included in
Table 79 produce fine papers with the percentage of clays
and fillers shown. As shown, the flow ranges from 25.8 to
137.6 kl/kkg (6.2 to 33.0 kgal/ton) with an average of 63.4
kl/kkg (15.2 kgal/ton). The BOD5 RWL has a range from 7.15
256
-------
Table 78
ESTIMATED NON-EQUILIDRIUM PAPERMAKI^G LOSSES
ro
SUBCATECORY
Groundwood
Suifite
Bleached
Kraft
Soda
Deink
Fine Paper
Tissue
Coarse Paper
MILL START UP
CODE BOD5 TSS
010 0.25(0.5)-2
012
014
052
101
102
107
113 4.5(9)-208
116 6.35(0.7)-1248 0.65(1.3)-124S
119
121 0.3(0.6)
126 1.5(3) 1.5(3)
151
152 0.6(1.2)-12 1.2(2.4)-12
204
205
261
266
267
306
308
315 2.45(4.9)-! 4.9(9.8)-!
353 15.5(31)-365
360
SHUTDOWN
BODc TSS
0.25(0.5)-8
(5.5)11 11(22)
4.5(9)
1.5(3)-36
2.25(4.5)-2
1(2) 4(3)
4.5(9)-2C3
0.65(1.3)-1248 1.3(2.6)-1248
12(2.'*)
0.65(1.3)
1.5(3) 1.5(3)
1.05(2.1) 0.65(1.3)
1.6(3.2)-6 3.53(7.i)-6
20(40)-25
2.5(5)-24
2.15(4.3)-104 4.3(S.6)-1C4
9(13)-52
1.45(2.9)-26
2.45(4.9)-! 4.9(9.8)-!
8(16)-365
0.8(1.6) 0.1(0.2)
NOTE: Nuabers following hyphen indicate estimated number of occurrences per year.
-------
Table. 78 (C0nt.)
MILL
SUBCATEGORY CODE
Groundwood 010
012
014
Sulfite 052
Bleached
Kraft 101
102
107
113
116
119
121
126
ro
wi Soda 151
00 152
Deink 204
205
Fine Paper 261
266
267
Tissue 306
303
315
Coarse Paper 353
360
GRADE CHANGE
BOD_ TSS
5.5(ll)-224 ll(22)-224
15(30)-120
0.85(1.7)-288 1.75(3.5)-288
0.4(0.8) 0.55(1.1)
1.2(2.4)-52 2..'.(4.8)-52
9(18)
4.3(8.6)-1095 8.5(17)-1095
9(18)-104
4.15(8.3)-52
8 (16) -365
WIRE CHANGE
EOD5 TSS
0.15(0.3)-45
5.5(ll)-33 ll(22)-33
0.9(1.8)
4.5(9)-5
0.65(1.3)-36 1.3(2.6)-36
0.65(1.3)
1.5(3) 1.5(3)
1.2(2.4)-12 24(48)-12
2.25(4.5)-2
1.45(2.9)-6
0.8(1.6) 0.1(0.2)
NOTE: Numbers following hyphen indicate estimated number of occurrences per year.
-------
a 78 (Cont.)
MILL WAS HUP
SUB CATEGORY
Groundwood
Sulfite
Bleached
Kraft
Soda
Deink
Fine Paper
Tissue
Coarse Paper
CODE BOD5
010
012 5.5(ll)-248
014
052
101
102
107
113
116
119
121
126 1.5(3)
151
152 0.6(1.2)-52
204
205
261
266
267
306 0.05(0.1)-52
308
315
353
360 0.35(0.7)
TSS
0.05(0.1)-310
ll(22)-248
2.5(5)-100
1.5(3)-36
3.75(7.5)
1.5(3)
2.0(4.0)-52
0.3(0. 6)-52
1.45(2.9)-26
5.5(ll)-35
0.05(0.1)
NOTE: Numbers following hyphen indicate estimated number of .ccurrences per year.
-------
TABLE 79
RAW WASTE IDAD
MI FINE PAPERS SUBCATEGORY
Mill
272
253
266
261
257
255
250
276
281
275
270
265
284
402
269
277
279
274
C&F(%)
-
5
9
9
10
10
10
10
10
10
10
12
15
15
20
20
25
25
Average
Production
kkg/day (tons/day)
73 ( 80)
218
217
100
180
57
84
48
380
373
18
415
389
269
101
573
561
18
(240)
(239)
(110)
(199)
( 63)
( 93)
( 53)
(364)
(411)
( 20)
(458)
(374)
(297)
(111)
(632
(618)
( 20)
Flow
kl/kkg(kgal/ton)
37.9 ( 9.1)
77.1
49.2
26.3
39.6
37.9
53.8
39.2
73.0
90.5
108.0
69.2
25.8
57.5
99.7
80.5
37.5
137.6
63.4
(18.5)
(11.8)
( 6.3)
( 9.5)
( 9.1)
(12.9)
( 9.4)
(17.5)
(21.7)
(25.9)
(16.6)
( 6.2)
(13.8)
(23.9)
(19.3)
( 9.0)
(33.0)
(15.2)
BOD5
kg/kkg (Ibs/ton)
10.9 (21.8)
7.3
12.8
8.6
9.1
-
-
19.1
-
-
11.3
11.2
7.6
7.5
-
16.1
-
7.1
10.7
(14.7)
(25.6)
(17.3)
(18.3)
( - )
( - )
(38.3)
( - )
( - )
(22.7)
(22.4)
(15.2)
(15.0)
( - )
(32.3)
( - )
(14.3)
(21.5)
mg/L
287
95
260
329
229
-
-
489
-
-
105
162
294
130
-
201
-
52
170
TSS
kg/kkg (Ibs/ton)
23.6 (47.2)N
31.1
22.8
22.1
38.4
-
-
38.4
-
-
31.0
29.2
30.3
43.5
18.2
123.5
-
-
30.8
(62.3)
(45.7)
(44.3)N
(76. 8) N
( - )
( - )
(76.9)
( - )
( - )
(62.0)
(58.4)N
(60.7)
(87.1)
(36.4)
(247)N
( - )
( - )
(61.6)
mgA
622
404
464
863
959
-
-
981
-
-
-
422
1174
757
183
153
-
-
486
N Non-standard methods TSS analytical measurement technique.
-------
to 38.3 Ibs/ton) with an average of 10.75 kg/kkg (21.5
Ibs/ton). The TSS RWL has an average of 30.8 kg/kkg (61.6
Ibs/ton). The subcategory RWL are therefore the following:
Flow: 63.4 kl/kkg (15.2 kgal/ton)
BOD5_: 10.75 kg/kkg (21.5 Ibs/ton)
TSS: 30.8 kg/kkg (61.6 Ibs/ton)
Non-Integrated Tissue Papers Subcategory
Information and data on the surveyed non-integrated tissue
mills are summarized in Table 80. Table 80 is divided into
two groups of mills, one using 100% purchased pulp and the
other using varying percentages of purchased pulp and waste
paper. The averages for each group show no difference in
effluent flow volumes with a slightly higher BOD5_ RWL for
mills using some waste paper. As shown in Table 80, the
subcategory RWL are the following:
Flow: 95.9 kl/kkg (22.9 Ibs/ton)
BOD_5: 11.5 kg/kkg (22.9 Ibs/ton)
TSS: 34.7 kg/kkg (69.4 Ibs/ton)
Consideration was given to subcategorizing on the basis of
waste paper usage because of the slightly higher RWL
attributed to mills using waste paper. Evaluation of final
effluent data following external treatment showed that
similar final effluent characteristics could be achieved by
similar treatment systems for mills using varying
percentages of purchased pulp and waste paper and thereby
further subcategorization was not warranted. However, mills
using 100% waste paper showed significantly higher external
treatment effluent characteristics due to increased
proportions of soluble BOD5_ in the waste water. Thus, a
separate subcategory was established for mills using 100%
waste paper to produce tissue papers.
Non-Integrated Tissue Papers (fwp) Subcategory
Information and data were available from four mills using
100% waste paper to produce tissue papers. Table 81
summarises the RWL data for these four mills. As shown, the
data are based upon few data points except for mill 320.
The average for all mills irregardless of the number of data
points was 105 kl/kkg (25.2 kgal/ton) with a range of values
from 27.9 to 205 kl/kkg (6.7 to 49.1 kgal/ton). Both the
high and low flow values are atypical of non-integrated
paper mills and were therefore excluded. Flows from mills
320 and 330 were averaged to obtain the flow basis of the NI
tissue (fwp) subcategory RWL. The BODS data shown in Table
261
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TABI£ 80
RAW WASTE LOAD
MI TISSUE SUBCATEGORY
Mill Manufactured (%)
PP WP
308
325
318
315
306
252
319
208
329
302
310
324
328
334
309
333
259
326
100
100
100
100
100
100
100
Average
60
62
65
70
70
70
70
80
80
85
-
Average
Average (for
0
0
0
0
0
0
0
40
38
35
30
30
30
30
20
20
15
-
all mills)
Size
kkg/day ( tons/day)
141
111
113
926
20
94
67
205
42
258
71
229
18
148
176
59
(156)
(122)
(125)
(1021)
( * )
( * )
( 22)
(104)
( 74)
(226)
( 46)
(285)
( 78)
(253)
( 20)
(163)
(194)
( 65)
Flow
kl/kkg(kgal/ton)
m.o
130.9
140.5
66.3
43.4
47.9
120.1
94.2
61.3
153.9
50.9
96.7
97.2
150.5
94.6
69.6
133.4
73.8
72.5
95.9
95.5
(26.6)
(31.4)
(33.7)
(15.9)
(10.4)
(11.5)
(28.8)
(22.6)
(14.7)
(36.9)
(12.2)
(23.2)
(23.3)
(36.1)
(22.7)
(16.7)
(32.0)
(17.7)
(17.4)
(23.0)
(22.9)
BODs
kg/kkg(lbs/ton)
15.1
-
-
8.7
-
-
7.3
10.4
22.8
-
11.7
7.4
15.9
10.0
13.6
14.6
-
9.6
-
11.8
11.5
(30.2)
( - )
( - )
(17.4)
( - )
( - )
(14.7)
(20.8)
(45.7)**
( - )
(23.5)
(14.8)
(31.8)
(20.0)
(27.3)
(29.3)
( - )
(19.2)
( - )
(23.7)
(22.9)
TSS
kkg/kkg(lbs/ton)
32.2
-
-
25.7
-
-
35.8
32.2
72
-
36.6
22.4
35.6
10.4
51.5
25.2
-
32.1
-
35.3
34.7
(64.4)
( - )
( - )
(51.5)N
( - )
( - )
(71.7)N
(64.4)
( 145)**
( - )
(73.3)N
(44.8)
(71.2)N
(20.9)N
( 103)
(50.4)^
( - )
(64.3)
( - )
(70.7)
(69.4)
* Trade Secret
** Not included in subcateqory average
N Non-standard methods TSS analytical measurement technique.
-------
TABLE 81
RAW WASTE LOADS
NI TISSUE (FWP) SUBCATEGORY
Production FLOW-NOV* BOD5 TSS
Mill kkg/day (tons/day) kl/kkg (kgal/ton) kg/kkg(Ibs/ton) kg/kkg (Ibs/ton)
no
o^
CO
330
320
313
312
18
60
34
14
(20)
(66)
(37)
(15)
79
109
27
205
.2
.0
.9
.0
(19
(26
( 6
(49
.0)-NA
.D-3
.7)-345
.l)-29
11
13
11
.6
.0
.5
—
(23
(26
(23
.2)**
.0)
.0)**
—
-
88.0 (176)
-
133.0 (266)
* NCV = Nunber of Values reported
** Primary treatment effluent
-------
81 is also limited as the mills 330 and 313 only have
primary treatment effluent data. A BOD5_ removal rate of 20%
through primary treatment was used to calculate the BOD5_ RWL
of 14.5 kg/kkg (29.0 Ibs/ton). The TSS RWL was based upon
the NI tissue mill's RWL (See Table 80).
264
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SECTION VI
SELECTION OF POLLUTANT PARAMETERS
WASTE WATER PARAMETERS OF SIGNIFICANCE
After a thorough analysis of the literature, mill records,
survey and NPDES data, the following pollutant parameters
have been identified and should be controlled:
BOD5
Total Suspended Solids
PH
Color (Not including Groundwood, Deinked, and Non-Integrated
subcategories)
Ammonia Nitrogen (Ammonia base Sulfite and Ammonia Base
Dissolving Sulfite only)
Zinc (Groundwood subcategories only)
Selection of Pollutant Parameters
The U.S. Environmental Protection Agency published (Federal
Register, Volume 38, No. 199, pp. 28758-28670, October 16,
1973) 40 CFR 136 "Guidelines Establishing Test Procedures
for the Analysis of Pollutants." Seventy-one pollutant
parameters were covered. This list with the addition of pH,
which was not included, provides the basis for the selection
of pollutant parameters for the purpose of developing
effluent limitations and standards. All listed parameters
are selected except for those excluded for one or more of
the following reasons:
1. Not harmful when selected parameters are controlled
2. Not present in significant units
3. Not controllable
4. Control substitutes a more harmful pollutant
5. Insufficient data available
6. Indirectly controlled when selected parameters are
controlled.
7. Indirectly measured by another parameter
265
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Environmental Effects of Waste Waters from Pulp and Paper
Mills
Serious aquatic and marine biology problems have been
ascribed to the discharge of pulping wastes into surface
waters (50) (51). Some of these include deoxygenation,
toxicity to fish, and interference with shell fish spawning.
Biological imbalance in streams has also occurred due to
slime growths engendered by wood sugars and fatty acids
present in the wastes (53)(54) (55). Such growths clog
fishing nets and thus shorten fishing time and pose a
difficult net cleaning problem. In many cases, unsightly
accumulations develop upon or become attached to objects in
contact with the water. Field and laboratory studies have
demonstrated that slime growth can be inhibited by any
process capable of reducing the amount of sugar and related
compounds discharged and that waste receiving effective
biological treatment will not normally cause infestations of
these organisms (56).
A further stream problem is the presence of ammonia in
effluents from ammonia base sulfite pulping. The effluent
from one such mill was found to contain from 96 to 189 mg/1
of NH3-N (57). This must be considered in terms of the
ultimate maximum concentration which will result in a body
of fresh water from its utilization of oxygen in oxidizing
to nitrates and in terms of the public health significance
in relation to downstream use of the water for potable
purposes.
266
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Biochemical Oxygen Demand (BOD5)
Biochemical oxygen demand (BOD) is the quantity of oxygen
required for the biological and chemical oxidation of
waterborn substances under ambient or test conditions.
Materials which may contribute to the BOD include:
carbonaceous organic materials usable as a food source by
aerobic organisms; oxidizable nitrogen derived from
nitrites, ammonia and organic nitrogen compounds which serve
as food for specific bacteria; and certain chemically
oxidizable materials such as ferrous iron, sulfides,
sulfite, etc. which will react with dissolved oxygen or are
metabolized by bacteria. In most industrial and municipal
waste waters, the BOD derives principally from organic
materials and from ammonia (which is itself derived from
animal or vegetable matter).
The BOD of a waste exerts an adverse effect upon the
dissolved oxygen resources of a body of water by reducing
the oxygen available to fish, plant life, and other aquatic
species. Conditions can be reached where all of the
dissolved oxygen in the water is used resulting in anaerobic
conditions and the production of undesirable gases such as
hydrogen sulfide and methane. The reduction of dissolved
oxygen can be detrimental to fish populations, fish growth
rate, and organisms used as fish food. A total lack of
oxygen due to the exertion of an excessive BOD can result in
the death of all aerobic aquatic inhabitants in the affected
area.
Water with a high BOD indicates the presence of decomposing
organic matter and associated increased bacterial
concentrations that degrade its quality and potential uses.
A by-product of high BOD concentrations can be increased
algal concentrations and blooms which result from
decomposition of the organic matter and which form the basis
of algal populations.
The BOD5 (5-day BOD) test is used widely to estimate the
pollutional strength of domestic and industrial wastes in
terms of the oxygen that they will require if discharged
into receiving streams. The test is an important one in
water pollution control activities. It is used for
pollution control regulatory activities, to evaluate the
design and efficiencies of waste water treatment works, and
to indicate the state of purification or pollution of
receiving bodies of water.
Complete biochemical oxidation of a given waste may require
a period of incubation too long for practical analytical
267
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test purposes. For this reason, the 5-day period has been
accepted as standard, and the test results have been
designated as BOD5_. Specific chemical test methods are not
readily available for measuring the quantity of many
degradable substances and their reaction products. Reliance
in such cases is placed on the collective parameter, BODJ5,
which measures the weight of dissolved oxygen used by
microorganisms as they oxidize or transform the gross
mixture of chemical compounds in the waste water. The
biochemical reactions involved in the oxidation of carbon
compounds are related to the period of incubation. The
five-day BOD normally measures only 60 to 80% of the
carbonaceous biochemical oxygen demand of the sample, and
for many purposes this is a reasonable parameter.
Additionally, it can be used to estimate the gross quantity
of oxidizable organic matter.
The BOD5_ test is essentially a bioassay procedure which
provides an estimate of the oxygen consumed by
microorganisms utilizing the degradable matter present in a
waste under conditions that are representative of those that
are likely to occur in nature. Standard conditions of time,
temperature, suggested microbial seed, and dilution water
for the wastes have been defined and are incorporated in the
standard analytical procedure. Through the use of this
procedure, the oxygen demand of diverse wastes can be
compared and evaluated for pollution potential and to some
extent for treatability by biological treatment processes.
The BOD5 test is also an indicator of the total organic load
that is being discharged to a receiving stream. Compounds
contributing to this total organic waste load found in pulp
and paper mill wastes include terpenes, resin acids, fatty
acids, phenols, formic acid, acetic acid, sacharinic acids
and other small organic acids. These compounds also
contribute to the toxicity of a pulp and paper mill waste.
A report entitled "Organic Compounds in Aerated
Stabilization Basin Discharge" published in TAPPI in October
1975 indicates that biological treatment sytems are very
successful in eliminating several of the above compounds
from kraft mill waste waters. Resin acids, fatty acids,
terpenes, hydrocarbons, and phenols were found to be reduced
to the same extent as the overall BOD removal efficiency.
The available tests for toxicity are quite expensive,
complicated, and subject to many variabilities. Data exists
to show that toxicity of pulp mill wastes can be reduced to
acceptable levels with appropriate reductions of BOD in the
waste. Oil and grease in a pulp and paper waste is not
readily discernible by the normal test methods because of
268
-------
interferences from lignins and other wood products. Foam is
a parameter that is generally considered unacceptable in a
receiving water. Again it is generally assumed that oil and
grease can be reduced to an acceptable level with an
appropriate reduction of BODji and foam can be reduced with
BOD5> reduction and installation of proper technology.
Total Suspended Solids (TSS)
Suspended solids include both organic and inorganic
materials. The inorganic components discharged by pulp and
paper mills include sand, silt, clay and other papermaking
additives. The organic fraction includes such materials as
fiber and other wood components such as lignin, tannins, and
sugars. These solids may settle out rapidly and bottom
deposits are often a mixture of both organic and inorganic
solids. Solids may be suspended in water for a time, and
then settle to the bed of the stream or lake. These 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.
Suspended solids in water interfere with many industrial
processes, cause foaming in boilers and incrustations on
equipment exposed to such water, especially as the
temperature rises. They are undesirable in process water
used in the manufacture of steel, in the textile industry,
in laundries, in dyeing, and in cooling systems.
Solids in suspension are aesthetically displeasing. When
they settle to form sludge deposits on the stream or lake
bed, they are often damaging to the life in water. 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 nature, solids use a portion or all of the
dissolved oxygen available in the area. Organic materials
also serve as a food source for sludgeworms and associated
organisms.
Disregarding any toxic effect attributable to substances
leached out by water, suspended solids may kill fish and
shellfish by causing abrasive injuries and by clogging the
gills and respiratory passages of various aquatic fauna.
Indirectly, suspended solids are inimical to aquatic life
because they screen out light, and they promote and maintain
the development of noxious conditions through oxygen
269
-------
depletion. This results in the killing of fish and fish
food organisms. Suspended solids also reduce the
recreational value of the water.
Of special interest is the BODj> or oxygen demand exerted due
to the microbial floe which are discharged from secondary
treatment facilities. The microbial solids in secondary
effluent are not inert and will exert an oxygen demand as
the microbes continue to metabolize. The predominant
metabolic reaction is endogenous respiration which exerts
the remaining oxygen demand. The endogenous oxygen demand
is exerted at a slow, continuing rate. The traditional five
day BOD5 test will not provide a complete estimate of the
total demand of the solids. The total oxygen demand will be
exerted after a long period of time and hence a long term
BOD5 test is necessary to obtain a reasonable estimate of
such a demand. Therefore it is in the best interest of the
receiving water to reduce the suspended solids level of a
discharge to as low a level as possible.
Most suspended solids of mill origin can be removed by
proper treatment, as described in Section VII. Suspended
solids of biological origin which are generated by
biological treatment are included in the test.
The deposition and accumulation of organic material from
municipal, industrial, and agricultural sources can result
in a decrease in dissolved oxygen in bottom sediments and
other chronic effects which are detrimental to a freshwater
or marine ecosystem. The adverse effects of sludge deposits
can occur independently of the condition of the overlying
water. Anaerobic sediments will kill benthic organisms that
require oxygen in the sediments to survive. If bottom
deposits become anaerobic, hydrogen sulfide, methane and
carbon dioxide gases can be produced. These ebullient gases
can effect unstable bottoms and raise mats of decaying
organic matter which are odiferous and aesthetically
unpleasing. In addition to sulfides, ammonia is produced
from the decomposition of protein and both these materials
may be toxic to aquatic life. Filling in of aquatic
environments by the sediments and the release of nutrients
by decomposition contribute to eutrophication. Low
dissolved oxygen concentrations in sediments can kill the
eggs of important fish that deposit them on the bottom (such
as salmon and trout) or build nests {such as bass and
bluegills). Suspension of organic sediments of oxygen
demanding sludge during rainfall and increasing river
velocities and turbulence, can exert an oxygen demand on the
overlying waters and may result in massive fish kills.
Sludge deposits also can harbor pathogenic microorganisms
270
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that may increase in numbers because of growth supported by
organic nutrients in the decaying deposit.
Acidity and Alkalinity - pH
Although not a specific pollutant, pH is related to the
acidity or alkalinity of a waste water stream. It is not a
linear or direct measure of either, however, it may properly
be used as a surrogate to control both excess acidity and
excess alkalinity in water. The term pH is used to describe
the hydrogen ion - hydroxyl ion balance in water.
Technically, pH is the hydrogen ion concentration or
activity present in a given solution. pH numbers are the
negative logarithm of the hydrogen ion concentration. A pH
of 7 generally indicates neutrality or a balance between
free hydrogen and free hydroxyl ions. Solutions with a pH
above 7 indicate that the solution is alkaline, while a pH
below 7 indicates that the solution is acid.
Knowledge of the pH of water or waste water is useful in
determining necessary measures for corrosion control,
pollution control, and disinfection. Waters with a pH below
6.0 are corrosive to water works structures, distribution
lines, and household plumbing fixtures and such corrosion
can add constituents to drinking water such as iron,
copper, zinc, cadmium, and lead. Low pH waters not only
tend to dissolve metals from structures and fixtures but
also tend to redissolve or leach metals from sludges and
bottom sediments. The hydrogen ion concentration can affect
the "taste" of the water and at a low pH, water tastes
"sour".
Extremes of pH or rapid pH changes can exert stress
conditions or kill aquatic life outright. 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. For example, metalocyanide complexes can
increase a thousand-fold in toxicity with a drop of 1.5 pH
units. Similarly, the toxicity of ammonia is a function of
pH. The bactericidal effect of chlorine in most cases is
less as the pH increases, and it is economically
advantageous to keep the pH close to 7.
*The term toxic or toxicity is used herein in the normal
scientific sense of the word and not as a specialized
term referring to section 307 (a) of the Act.
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Acidity is defined as the quantitative ability of a water to
neutralize hydroxyl ions. It is usually expressed as the
calcium carbonate equivalent of the hydroxyl ions
neutralized. Acidity should not be confused with pH value.
Acidity is the quantity of hydrogen ions which may be
released to react with or neutralize hydroxyl ions while pH
is a measure of the free hydrogen ions in a solution at the
instant the pH measurement is made. A property of many
chemicals, called buffering, may hold hydrogen ions in a
solution from being in the free state and being measured as
pH. The bond of most buffers is rather weak and hydrogen
ions tend to be released from the buffer as needed to
maintain a fixed pH value.
Highly acid waters are corrosive to metals, concrete and
living organisms, exhibiting the pollutional characteristics
outlined above for low pH waters. Depending on buffering
capacity, water may have a higher total acidity at pH values
of 6.0 than other waters with a pH value of 4.0.
Alkalinity: Alkalinity is defined as the ability of a water
to neutralize hydrogen ions. It is usually expressed as the
calcium carbonate equivalent of the hydrogen ions
neutralized.
Alkalinity is commonly caused by the presence of carbonates,
bicarbonates, hydroxides and to a lesser extent by borates,
silicates, phophates and organic substances. Because of the
nature of the chemicals causing alkalinity, and the
buffering capacity of carbon dioxide in water, very high pH
values are seldom found in natural waters.
Excess alkalinity as exhibited in a high pH value may make
water corrosive to certain metals, detrimental to most
natural organic materials and toxic to living organisms.
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. Appreciable irritation will
cause severe pain.
Some data is available which shows that in certain
subcategories, improved coliform and total suspended solids
reductions took place at a pH in the 5 to 55 range. Other
data did not show this but did show that there may be an
optimum pH for each particular mill or subcategories. Where
data was limited for certain subcategories it could not be
shown whether or not a pH of less than 6 would improve
suspended solids levels.
272
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Since the Agency considers reduction of suspended solids a
necessary part of BPCTCA it is recommended that the
allowable pH range for the pulp and paper subcategories in
this document be 5.0 to 9.0 to provide flexibility to the
industry to adjust pH levels to obtain optimum suspended
solids reduction. This range is within the range where the
acidity content in the waste stream is primarily due to the
carbon dioxide equilibrium and should be easily buffered by
most receiving waters.
Color
Color is defined as either "true" or "apparent" color. In
Standard Methods for the Examination of Water and Wastewater
(191) , 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 process. The wash water is
highly colored, and large amounts of color are ultimately
discharged to the receiving stream despite some recovery
operations.
Colored effluents may have the following detrimental effects
upon receiving waters; 1) color retards sunlight
transmission and may interfere with photosynthesis thereby
reducing the productivity of the aquatic community; 2)
natural stream color is altered, thus detracting 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 organisms for 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
may affect fish movements and fish productivity, 7) color
bodies exert a long term BOD5 (20-60 days up to 100 days)
not measured by the BODi> test.
273
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Ammonia (NH_3)
Ammonia occurs in surface and ground waters as a result of
the decomposition of nitrogenous organic matter. It is one
of the constituents of the complex nitrogen cycle. It may
also result from the discharge of industrial wastes from
chemical or gas plants, from refrigeration plants, from
scouring and cleaning operations where "ammonia water" is
used from the processing of meat and poultry products, from
rendering operations, from leather tanning plants, and from
the manufacture of certain organic and inorganic chemicals.
Because ammonia may be indicative of pollution and because
it increases the chlorine demand, it is recommended that
ammonia nitrogen in public water supply sources not exceed
0.5 mg/1.
Ammonia exists in its non-ionized form only at higher pH
levels and is 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 (NO_3) 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 objectionable
components of mineralized waters. Excess nitrates cause
irritation to the gastrointestinal tract, causing diarrhea
and diuresis. Methemoglobinemia, a condition characterized
by cyanosis and which can result in infant and animal
deaths, can be caused by high nitrate concentrations in
waters used for feeding. Ammonia can exist in several other
chemical combinations, including ammonium chloride and other
salts. Evidence exists that ammonia exerts a toxic effect
on all aquatic life depending upon the pH, dissolved oxygen
level, and the total ammonia concentration in the water. A
significant oxygen demand can result from the microbial
oxidation of ammonia. Approximately 4.5 grams of oxygen are
required for every gram of ammonia that is oxidized.
Ammonia can add to eutrophication problems by supplying
nitrogen to aquatic life. Ammonia can be toxic, exerts an
oxygen demand, and contributes to eutrophication.
Pulp and papermaking waste flows normally contain only minor
concentrations of this nutrient, and nitrogen compounds must
often be added to provide desired biological waste treatment
efficiencies. As a result, effluent limitations on nitrogen
274
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are not considered necessary except for ammonia base sulfite
and ammonia base dissolving sulfite mills.
Insufficient data exists to determine representative ammonia
nitrogen levels discharged by these mills, but sparse data
indicate that their effluents contain 1 to 3 kg/kkg (2 to 6
Ib/ton). No technology is currently available or
anticipated for 1983 for removing ammonia nitrogen at the
flows and concentrations found in these effluents.
Zinc (Zn)
Occurring abundantly in rocks and ores, zinc is readily
refined into a stable pure metal and is used extensively as
a metal, an alloy, and a plating material. In addition,
zinc salts are also used in paint pigments, dyes, and
insecticides. Many of these salts (for example, zinc
chloride and zinc sulfate) are highly soluble in water;
hence, it is expected that zinc might occur in many
industrial wastes. The major source of zinc from pulp and
paper mills is due to the use of zinc hydrosulfite as a
bleaching agent in groundwood mills. On the other hand,
some zinc salts (zinc carbonate, zinc oxide, zinc sulfide)
are insoluble in water and, consequently, it is expected
that some zinc will precipitate and be removed readily in
many natural waters.
In soft water, concentrations of zinc ranging from 0.1 to
1.0 mg/1 have been reported to be lethal to fish. Zinc is
thought to exert its toxic action by forming insoluble
compounds with the mucous that covers the gills, by damage
to the gill epithelium, or possibly by acting as an internal
poison. The sensitivity of fish to zinc varies with
species, age, and condition, as well as with the physical
and chemical characteristics of the water. Some
acclimatization to the presence of the zinc is possible. It
has also been observed that the effects of zinc poisoning
may not become apparent immediately so that fish removed
from zinc-contaminated to zinc-free water may die as long as
i»8 hours after the removal. The presence of copper in water
may increase the toxicity of zinc to aquatic organisms,
while the presence of calcium or hardness may decrease the
relative toxicity.
A complex relationship exists between zinc concentrations,
dissolved oxygen, pH, temperature, and calcium and magnesium
concentrations. Prediction of harmful effects has been less
than reliable and controlled studies have not been
extensively documented.
275
-------
Concentrations of zinc in excess of 5 mg/1 in public water
supply sources cause an undesirable taste which persists
through conventional treatment. Zinc can have an adverse
effect on man and animals at high concentrations.
Observed values for the distribution of zinc in ocean waters
varies widely. The major concern with zinc compounds in
marine waters is not one of actute lethal effects, but
rather one of the long term sublethal effects of the
metallic compounds and complexes. From the point of view of
accute lethal effects, invertebrate marine animals seem to
be the most sensitive organisms tested.
A variety of freshwater plants tested manifested harmful
symptoms at concentrations of 10 mg/1. Zinc sulfate has
also been found to be lethal to many plants and it could
impair agricultural uses of the water.
276
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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 of water is related to the amount of suspended and
colloidal matter contained in the water. It affects the
clearness and penetration of light. The degree of turbidity
is only an expression of one effect of suspended solids upon
the character of the water. Turbidity is in part measured
by the total suspended solids test and thereby, turbidity is
not considered as a separate pollutant.
Chemical Oxygen Demand (COD)
The chemical oxygen demand (COD) is a purely chemical
oxidation test devised as an alternate method of estimating
the total oxygen demand of a waste water. Since the method
relies on the oxidation-reduction system of chemical
analyses rather than on biological factors, it is more
precise, accurate, and rapid than the BOD test. The COD
test is widely used to estimate the total oxygen demand
(ultimate rather than 5-day BOD) to oxidize the compounds in
a waste water. It is based on the fact that organic
compounds, with a few exceptions, can be oxidized by strong
chemical oxidizing agents under acid conditions with the
assistance of certain inorganic catalysts.
The COD test measures the oxygen demand of compounds that
are biologically degradable and of many that are not.
Pollutants which are measured by the BODj> test will be
meausred by the COD test. In addition, pollutants which are
more resistant to biological oxidation will also be measured
as COD. COD is a more inclusive measure of oxygen demand
than is BODJ5 and will result in higher oxygen demand values
than will the BODj> test.
The compounds which are more resistant to biological
oxidation are becoming of greater and greater concern not
only because of their slow but continuing oxygen demand on
the resources of the receiving water, but also because of
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their potential health effects on aquatic life and humans.
Many of these compounds result from industrial discharges
and some have been found to have carcinogenic, mutagenic and
similar adverse effects, either singly or in combination.
Concern about these compounds has increased as a result of
demonstrations that their long life in receiving waters -
the result of a slow biochemical oxidation rate - allows
them to contaminate downstream water intakes. The commonly
used systems of water purification are not effective in
removing these types of materials and disinfection such as
chlorination may convert them into even more hazardous
materials.
Thus the COD test measures organic matter which exerts an
oxygen demand and which may affect the health of the people.
It is a useful anlytical tool for pollution control
activities. It provides a more rapid measurement of the
oxygen demand and an estimate of organic compounds which are
not measured in the BODS^ test.
The relationship between COD and BODjj before treatment is
not necessarily the same after treatment. Therefore, the
effluent limitations will include the BOD5 parameter, since
insufficient information is available on the COD effluent
levels after treatment.
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 U0% 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.
A geometric mean density of fecal coliforms of 1000/lOOmls
or less is generally indicative of adequate treatment.
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Resin Acids
Soaps of resin acids (isopimaric, abietric, and
dehydroabietric) have been identified as causing
biologically deleterious effects in kraft mill effluents.
Studies in Canada indicate that these compounds are
contained mainly in combined condensates rather than black
liquor. The most recent studies indicate that a reduction
in adverse 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.
Polychlorinated Biphenyls
Polychlorinated biphenyl (PCB) is a generic term covering a
family of partially or wholly chlorinated isomers of
biphenyl. The commercial mixtures generally contain 40-60%
chlorine with as many as 50 different detectable isomers
present. The PCB mixture is a colorless, viscous fluid
relatively insoluble in water that can withstand very high
temperatures without degradation. PCB's do not conduct
electricity, and the more highly chlorinated isomers are not
readily degraded in the environment.
PCB's can be used in paints, inks, and plastics. They are
also found in hydraulic system, in the manufacture of
transformers and capacitors, and in the wastes from the
reprocessing of certain papers.
The major uses of PCB's are a result of its nonconductivity
and persistence. These uses can be grouped in three major
categories: open uses, partially closed system uses, and
closed system uses. Open uses include paints, inks,
plastics, and paper coatings. The PCB's in all of these
products contact with the environment and can be leached out
by water. The so-called carbonless carbon paper contains
PCB's in the encapsulated ink and is claimed to be
responsible for the PCB's found extensively in recycled
paper. PCB's have been used as plasticizers in polyvinyl
chloride (PVC) and chlorinated rubbers.
Uses of PCB's in partially closed systems include the
working fluid in heat exchangers and hydraulic systems.
These systems have a potential for leakage of the PCB fluid
either during use or after being discarded.
The electrical industry is the single major consumer of
PCB's, mainly in a closed loop system in transformers and
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capacitors. The fluid is generally sealed into the unit so
that the loss, if any, is small. Transformers and
capacitors account for about 63% of all PCB use.
It is not known exactly how PCB1s are released into the
environment or in what quantities. Analyses of water
samples from 30 major tributaries to the Great Lakes
indicate widespread contamination, with 71% of all samples
having detectable concentrations (greater than 10 parts per
trillion). PCB's have been found in all organisms analyzed
from the north and south Atlantic, even in animals living
under 11,000 feet of water. It is reported that one-third
of the human tissue sampled in the United States contains
more than one part per million (ppm) of PCB's.
Once in the environment, PCB's appear to persist for a very
long time. Evidence for this can be seen in the fact that
in most areas of the continent and throughout the Atlantic
Ocean more PCB than DDT is found in the animals, even though
three times more DDT is produced each year, and all of it is
put directly into the environment. Based on present
available data, it seems safe to assume that PCB's are
present in varying concentrations in every species of
wildlife on earth.
Liver damage is a common effect of PCB's while the
occurrence of edema, skin lesions, and reproductive failure
depends on the species. Hatchability of eggs is noticeably
decreased by exposure to PCB's. These compounds have been
shown lethal and subsetal effects on fish and animals,
including reduced reproduction of the species and abnormal
young.
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SECTION VII
CONTROL AND TREATMENT TECHNOLOGIES
INTRODUCTION
Present control and treatment technology precludes zero
discharge of pollutants in virtually all subcategories
although a few non-integrated paper mills have approached
this goal. As discussed in Section V, however, significant
water use reductions have occurred in every subcategory
during recent years and new means are continually being
found for increased water reuse.
The pollution loads of effluents discharged to receiving
waters from all subject subcategories can be reduced to
required levels by conscientious application of established
in-plant process controls and water recycle measures
together with well designed and properly operated external
treatment facilities.
This section describes both the internal and external
technologies which are presently available to achieve
various levels of pollutant reduction for each of the
subcategories. In come cases "in-plant" and "external"
technologies merge. For example, a mill may employ
extensive suspended solids removal equipment internally,
reusing the clarified water in the process 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.
The use of various internal and external treatment
technologies in each subcategory is discussed more
specifically later in this section. In those discussions,
where numbers of mills are given by type of pulp produced,
these numbers refer to the mills assigned to that particular
subcategory according to the criteria discussed in Section
III. This is done to eliminate the duplication of mills
which would occur if complex pulping operations were
reported in more than one subcategory.
The products manufactured are a crucial determinant in the
degree of recycle possible for a given operation (181). For
example, in contrast to the non-integrated papermaking
operations mentioned above, there is no proven combination
of systems by which bleached kraft and other chemical pulp
mills can be designed and operated at zero discharge on a
continuous basis (182). One of the surveyed paper mills, on
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the other hand, has no pulping capacity and produces less
than 18.14 kkg/day (20 tpd) of coarse toweling paper, a
product whose specifications permit complete recycle of
process water. Another mill, producing 36 kkg/day (40 tpd)
of tissue, accomplishes zero discharge by clarifying and
filtering white water for use as paper machine showers and
seal water, although some white water is directly recycled
for stock preparation and dilution. This is economic for
this small mill because of its product and size in relation
to its arid geographic location.
INTERNAL TECHNOLOGIES
General
Internal control measures are procedures to reduce pollutant
discharges at their origin, some of which result in the
recovery of chemicals, fiber, and by-products as well as
conservation of heat and water. Similar methods are
available to all subject subcategories and include, where
applicable, effective pulp washing, chemical and fiber
recovery, treatment and reuse of selected waste streams,
collection of spills, and prevention of accidental
discharges. New processes to reduce pollutant loads are
continually being developed and are being incorporated into
new mills and, where feasible are being retrofitted into
existing mills.
Generally, mills which reduce raw waste loads concomitantly
reduce effluent flow through recycle.
A waste management program should include control of losses
which occur when the production process is not in
equilibrium such as spills, overflow, and wash-up. These
losses may account for one-third to one-half of the
suspended solids and BOD5 of the raw waste and can result
from a variety of factors, as discussed in Section V. These
include breakdown of equipment, routine maintenance, planned
shutdowns and startups, power failures, and grade changes.
Whereas mill production operations may be regarded as a
continuous sequential balanced series of unit operations, in
fact there exists a discontinuity in practice which makes
spills, overflows, and accidental discharges a common
problem as regards both internal control and influences on
external waste treatment facilities. Continuous monitoring
within mill sewers (especially conductivity) should be
employed to give immediate warning of unknown spills so that
corrective action can be taken promptly. Personnel should
be trained to respond with immediate remedial procedures in
addition to avoiding such spills. In some instances
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automatic diversion devices operated by conductivity
measuring instruments are employed.
Best practice also includes the use of storage facilities
adequately sized to avoid overflows in at least 90 percent
of process upsets and during maintenance procedures such as
periodic evaporator "boil out". Provision should be made to
return these stored materials to the originating subprocess
at a later time.
If overflows would cause treatment plant upset or increased
discharge of pollutants, production should be curtailed as
necessary if the overflows cannot be prevented by some other
means. Sewer segregation can be used, especially in new
mills, to minimize these impacts, in conjunction with
adequate storage.
Storage lagoons located prior to treatment may be provided
to accept longer term shock loads, the contents of which can
then be gradually returned to the process or diverted to
treatment without detriment to treatment operations.
Provision of storage lagoons also provides some period of
time to correct malfunction of external treatment operations
or offers temporary facilities for solids sedimentation if
properly designed to satisfy such uses. Fresh water used to
cool bearings, variable speed couplings, brake linings in
paper rewind applications, and similar areas throughout a
mill can be collected and reused. It is not contaminated
and can be recycled either directly after heat removal or
indirectly by discharge into the fresh water system if heat
buildup is not a problem.
Water used to cool condensate from steam dryers can
similarly be reused but because of high heat loads it is
usually necessary to cool this water with cooling towers or
other means. It is practical in some cases to return dryer
condensate directly to the feed water heater at the boiler
plant under 1.2-1.34 atm pressure (3-5 psig pressure),
thereby reducing the cooling water requirement. This
approach is more feasible where dryers are operated at
pressures above 1.34 atm (5 psig). While a reduction in
cooling water discharge does not minimize the pollutant
load, it does reduce the total volume of waste water to be
treated, thus decreasing the capital and, in some instances,
operating cost of waste treatment facilities.
Seal water is used on packing glands of process pumps,
agitators, and other equipment employing rotating shafts.
It cools bearings, lubricates the packing, minimizes leakage
of the process fluid and is commonly used in vacuum pumps as
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the vacuum seal. Even though the amount of water used per
packing is small -- generally in the range of 2 to 11 1/min
(0.5 to 3 gpm) — the total used is quite extensive because
of the large number of rotating shafts involved and may
approximate 4173-8346 1 (1000-2000 gal) per kkg (ton) of
product. This can be much higher with the extensive use of
water ring vacuum pumps. Methods used to reduce quantities
of water required include proper maintenance of packings and
flow control of individual seal water lines or installation
of mechanical seals. In some cases, seal water which leaks
from the packing can be collected and reused, usually after
filtering.
As discussed in Section III, barking of wood prior to
pulping is most commonly performed by dry processes which
require very little water. This practice is more desirable
than wet barking from the standpoint of raw waste loads.
The small amounts of effluent from dry barking are
preferably settled and recycled but are normally disposed of
on the land or combined with the general flow of mill
effluent.
Reduction of waste loads from wet barking can be achieved
through recycle of most of the barking water. If recycled
water is to be used in hydraulic barking, however, a high
degree of solids removal must be attained to prevent erosion
within pumps and barker nozzles. For this reason, the reuse
of water for this purpose is seldom if ever practiced.
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 roundwood will be barked
by pulp mills, thus reducing or eliminating waste water
discharges from this source.
Groundwood Subcategories
Raw wastes from groundwood mills can be reduced by good
housekeeping, water reuse, and recycling of screen rejects.
Most of the mills studied practice good housekeeping,
keeping spills to a minimum and controlling the use of
excessive amounts of gland seal water. However, it was
found that rejects from pulp screening are sewered in some
mills. They should be passed through a reject refiner as
described in Section III and returned to the process ahead
of the screens.
Water recycle is widely practiced in integrated groundwood
pulp and paper mills. More than 90 percent of the surveyed
mills recycle some paper machine white water either for
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reuse on showers or more commonly as makeup water in the
pulp mill. In some modern newsprint mills the groundwood
operation is completely closed with all waste water
appearing in the paper machine effluent.
Fifty-seven percent of the mills surveyed in 1973 and 1974
employ either vacuum or flotation savealls to reduce losses
from paper machines and 64 percent collect and reuse some
process hot water. Less than 10 percent of these mills are
reusing vacuum pump seal water or cooling waters. A more
detailed description of the BPCTCA technology used to reduce
effluent loads from paper mills is given later in this
section under Papermaking.
Steam softening is employed in some refiner groundwood mills
to soften the chips sufficiently for the refiners without
the expense and additional effluent involved in chemical
addition such as is employed in the cold soda or chemi-
groundwood processes. This steam softening does not,
however, constitute thermo-mechanical pulping as described
in Section III.
Total * recycling of effluent has been tried in two of the
chemi-groundwood mills studies. Trials have been abandoned
because of the severe equipment and piping corrosion
encountered. A total rebuild of the mill water system would
be required using expensive corrosion resistant material
throughout.
Water reuse in a bleached groundwood pulp mill is limited by
brightness reversion after bleaching. Several mills report
pilot studies to reduce discharge flow but no successful
zero discharge processes have been developed at this stage.
Sulfite Subcategories
The eighteen sulfite mills surveyed in 1973 and 1974
represent 62 percent of the mills in the sulfite and
dissolving sulfite subcategories. The waste load of this
subcategory is being reduced through switching to kraft
pulping, changing from a calcium to a soluble base and
evaporating and disposing of the liquor by burning (with or
without chemical recovery), or producing by-products from
it.
As discussed in Section V, the performance of sulfite
recovery systems is less effective in reducing sewer losses
than that of kraft systems because of the large quantity of
acetates and formates appearing in the condensates.
Although methods for the recovery of acetic and formic acid
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in soluble form have been developed (47)(48)(49), the market
for these acids is such that it does not represent a
dependable means of solving the problem of their disposal on
a continuous basis for more than an occasional mill.
Presently on-going research (290) involving steam stripping
and activated carbon adsorption of volatiles for
fractionation may produce a commercial process for removal
of methanol, acetic acid and furfural from sulfite
condensates. However, by neutralizing the spent liquor, a
large percentage of the BODJ5 normally contained in the
condensates can be retained in the liquor and ultimately
burned.
A. total of eight mills manufacture by-products ranging from
simple evaporates used for road binder and cattle food
additives to some more sophisticated formulations and
intermediates used in adhesives, dispersants, tanning
agents, drilling mud additives, etc. Since all of these
products account for only about 10 percent of the liquor
solids produced and for other reasons as well, they do not
represent a complete or permanent solution of the liquor
problem. Two mills produce food yeast and one mill alcohol
from fermentation processes utilizing the wood 'sugars
contained in sulfite liquors.
Two mills (95) which have converted from calcium to
magnesium base and incorporated liquor recovery have
achieved BOD5 reductions of 82 and 87 percent.
All of the mills surveyed recirculate some white water for
use on machine showers and the majority of them use high
pressure showers. These mills also collect and reuse some
process hot water. Paper machines in the surveyed sulfite
mills all incorporate savealls to reduce suspended solids in
their effluent.
Internal technology for effluent reduction in the bleaching
of sulfite pulps is included in a later section, Bleaching
of Chemical Pulps.
Bleached Kraft Subcategories
In older practice, the decker filtrate accounted for a major
portion of the sewer losses in bleached kraft mills. After
washing, the pulp was diluted to about one percent
consistency in order to promote effective 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 which contained spent liquor
not removed in the washing process typically accounted for
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one-third or more of the total BOD5 loss from the mill.
Improved washing techniques have now reduced this loss to
below a third of the total loss in terms of BOD5_.
Attempts to apply hot stock refining to reduce the dilution
requirement before screening have not been successful in
bleached pulp production. Newer type deckers actually
provide an additional washing stage which is beneficial to
the bleaching operation and lowers the pollution load
contained in the bleach plant effluent due to spent liquor
carryover (297). In addition less bleaching chemical is
required when the brown stock is well washed (298) (8).
While there is a potential for further reducing the
pollutants in the decker filtrate by providing greater
washing capacity, it has been pointed out (20) that this
procedure, if carried too far, succumbs to the law of
diminishing returns. Beyond a range of soda loss of 7.5 to
10 kg (15 to 20 lb) per kkg (ton) of pulp, the recovered
liquor is diluted to a point where evaporation capacity arid
attending heat requirements exceed the benefits derived.
Digester and evaporator condensates are also recognized as
principal BOD5_ contributors to the effluent load from kraft
mills. Consequently, considerable effort is expended in
most kraft operations to consume as much of these
condensates internally as possible by substituting them for
normal fresh water make-up applications. The condensates
are more frequently used in brown stock washing and in
causticizing make-up. Use of condensates in lime kiln stack
scrubbers and dissolving tank make-up is also a common
practice (58).
Despite the extensive condensate recycling practices, these
waste streams still constitute, collectively, a source of
air and water pollution from kraft operations. Many of the
problems related to condensates evolve from the recycling
practices themselves. In ideal waste recycle the waste
stream would be totally consumed in the process — i.e., the
polluting materials destroyed by incineration or
homogeneously assimilated into the process streams. This,
of course, is not entirely the case with condensates. Since
condensates in general are black liquor distillates, a large
fraction of the offending chemical substances involved are
volatile substances which are not amendable 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 thus
result in a gradual increase in the concentration of the
volatiles in the process stream involved. Consequently,
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distillate slip streams from the process may become enriched
with these volatiles to the extent that air and water
pollution problems occur in areas where no problems exist
without the recycling practices.
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 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 increased by the recycling
practice. Normally innocuous emission sources, such as tank
vents and vacuum pump exhausts, may also become fortified
through extensive condensate recycling.
Extensive condensate recycling may also create operational
problems. For example, the necessity for increasing wet
strength additive usage has been linked to multi-effect
evaporator condensate in brown stock washing. In addition,
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.
The condensate streams from the continuous pulping process
differ markedly from those of batch operations. The
continuous digester blow generally occurs at a lower
temperature and pressure than that of the batch cook. Thus,
the evolution of distillates in this function is
inconsequential in comparison to their production by a batch
counterpart. On the other hand, relief condensate,
characteristic of the batch cook, does not occur as such in
the continuous cook. However, condensates from continuous
digester steaming vessels may be compared with batch
digester relief condensate.
As mentioned previously the reuse of condensates is commonly
practiced by a large number of mills and the problems
associated with the reuse of condensates can generally be
taken into account through careful application for each
mill. Since each mill situation is slightly different in
some aspect, the reuse of condensates for a particular mill
depends upon the interrelationships between the
manufacturing equipment, the final product qualities, and
the extent of air and water pollution abatement facilities
on-site. Some mills have determined that reuse of
condensates on the brownstock washers is beneficial and that
the problems of odor and corrosion can be handled
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satisfactorily whereas other mills have determined that use
of condensates in the causticizing area is the better place
for reuse. The point is, that while problems can be created
by reuse of condensates, many mills have successfully reused
condensates and have solved the problems through careful
application of control technology for each particular
situation.
Methanol accounts for about 80 percent of the organic
content of evaporator condensates and for most of the BODj>
(96). Other alcohols, ketones, and small quantities of
phenolic substances, sulfur compounds, and turpenes account
for the remainder. Because of the odorous compounds, reuse
of those condensates has been restricted by air pollution
considerations. This led, about 10 years ago, to a search
for technology to remove such compounds. Steam stripping of
condensates has been studied extensively for this purpose
(97) (98) (59) (99) and has been successfully applied at two
bleached kraft mills in this country and by several abroad.
Recently reported application of steam stripping technology
applied to kraft condensates indicates that 75 percent of
the condensate BODf> due principally to methanol, may be
removed without difficulty and without odor problems (291).
Since methanol is readily oxidized by biological treatment
there is a valid question as to whether it is more
economical to remove it by stripping or in the effluent
treatment plant. It is likely that the answer to this
question is different from mill to mill and varies with
consideration of the other materials removed, and with the
relative costs of steam and electric power.
Air stripping combined with biological treatment in packed
towers has been tested on a large scale (100). While this
procedure is effective in achieving a measurable BOD5
reduction it releases odorous substances into the
atmosphere.
Inert materials originating in the wood and make-up
chemicals must be removed from the kraft chemical recovery
and cooking liquor preparation process. These are contained
in the dregs settled from the green liquor and in the grits
separated in the lime slaker. Separate land disposal of
these materials as practiced by most mills lowers the total
suspended solids content of the raw waste.
An alternative method of kraft chemical recovery is under
study. This hydropyrolysis recovery process (101) subjects
the black liquor to pretreatment which produces a low ash
char and a liquor containing essentially all of the sodium.
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A standard power boiler is used to burn the char and recover
its heat value and conventional recausticizing converts the
liquor to white liquor. The process offers economic,
environmental, and safety advantages as well as the
opportunity to produce new byproducts, particularly
activated carbon from the char. A recent EPA report (292)
on this work indicates development of a microlime-carbon
process capable of producing an effluent from unbleached
kraft production suitable for mill reuse.
Laboratory and pilot experiments have been conducted into
the use of oxygen in the pulping process. It was found
(103) that soda-oxygen pulping produced a nontoxic waste
water which was lower in color and had less tendency to foam
than effluents from kraft pulping to the same degree of
delignification. Interest in the several oxygen pulping
means under investigation is evident in this country as well
as Japan and the Scandinavian countries. A recent symposium
(293) served to update progress in this area of research.
Over half of the 74 bleached kraft mills were surveyed in
1973 and 1974. All of the surveyed mills are making
considerable use of a large number of the internal controls
mentioned above for the reduction of raw waste effluent.
Most of these mills are utilizing technologies which do not
require major process changes while 40 percent have made
major process or equipment modifications to reduce the level
of pollutants discharged.
All bleached kraft mills surveyed are reducing the quantity
of fresh water usad for brown stock washing through reuse of
decker filtrates for countercurrent washing. Sixty-two
percent of the mills are making extensive use of these
methods.
Seventy percent of the surveyed mills segregate knots,
dregs, grits, and similar materials from their liquid
effluent for disposal in a semisolid form. Black liquor and
stock spill collection systems are installed in 46 percent
of the surveyed mills while 62 percent collect evaporator
boil-out and over 80 percent reuse some evaporator
condensates. Collection and reuse of process hot water is
widely practiced in this subcategory, being used in 92
percent of the mills surveyed.
All surveyed paper mills associated with bleached kraft
pulping were found to be reusing at least a portion of
machine white water although only 20 percent are using high
pressure showers. In addition all these mills are making
use of savealls with 62 percent of the mills using this
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equipment extensively. Thirty-eight percent of these paper
mills are able to reuse vacuum pump seal water.
Soda Subcategory
Since this process, including chemical recovery is today
almost identical to kraft, most of the same control
technology can be applied to reduce the effluent discharge.
The major difference is the absence of sulfur from the soda
process, and thus almost no odor is created. All three soda
mills were included in survey visits. All these mills
recycle decker filtrate for brownstock washing with two
mills making extensive use of this technology. Two of the
three mills segregate knots and dregs for separate disposal
and also use spill collection and reuse of contaminated
condensates to reduce the discharge of pollutants.
All three mills also collect and reuse process hot water,
employ savealls and recycle white water with two of the
three using high pressure showers. One mill reuses vacuum
pump seal water and cooling water.
Bleaching of Chemical Pulps
High reduction of the pollution losses from bleach plants at
chemical pulping mills can only be effected by process
change despite the drastic reductions in effluent volume
frequently possible to achieve. While water recycle in
bleach plants has advanced remarkably in recent years, with
flow from high brightness bleaches dropping to as low as
25,000 1 (6000 gal) of fresh water per kkg (ton) of product
(10U) , no reduction in pollution load accompanies water
economy. This is because conventional bleaching is
dependent upon the removal of color bodies and in doing this
chemically, some hydrolysis occurs and some materials are
leached from the pulp. These pollutants are not normally
recoverable because of their dilute nature and high chloride
content which is corrosive to recovery systems (299) and
which in high concentration in the smelt can cause
explosions. Water recycle does, however, reduce the total
volume of water requiring treatment with consequent savings
in size and cost of treatment plants.
Some reduction of bleach plant pollution load can be
achieved by controlling digestion where possible in order to
remove more lignin in the brown stock washer, leaving less
to be discharged at the bleach plant.
Reduction in effluent flows can be achieved by
countercurrent recycling of shower and seal box waters.
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This is possible in most bleach plant configurations,
eliminating flows to sewers from downstream stages. Three
main types of countercurrent washing are used in bleacheries
direct, split-flow, and jump stage. Direct
countercurrent washing produces the least effluent. Some
countercurrent washing is practiced by 90 percent of the
bleached kraft mills surveyed. The jump stage process is
used by a majority of the surveyed sulfite and dissolving
sulfite mills and to some extent by all three soda mills.
The use of countercurrent flow in existing mills, however,
is restricted in that serious corrosion problems are
encountered when washers contacted by chlorine dioxide
filtrates are not of 317 stainless steel. Partial or
jumpstage washing can be used with some savings when washer
and pipeline material prohibit a complete recycle system.
Paper mill white water or excess mill hot water can be used
as make-up water or for the final stage washer and fresh
water added only in time of process problems. The use of
317 stainless steel eliminates shower corrosion but shower
pluggage has caused problems in some mills. Some
readjustment of chemical dosing rates are required as is pH
adjustment in some systems.
In several mills in addition to limiting water use
countercurrent washing has considerably reduced steam
requirements (104). Laboratory and mill trials have shown
(105) a potential for considerable reduction in water use in
bleacheries by eliminating some pulp washing without
affecting brightness and chemical consumption. In a five
stage operation bleaching softwood kraft pulp, it was
possible to eliminate washing after the first chlorine
dioxide stage. In a five stage hardwood kraft bleachery,
the wasing following both the first chlorine dioxide and the
second caustic extraction stages was successfully
eliminated. Countercurrent washing should be discontinued
when dirt is encountered in the bleach plant to avoid
prolonged dirt problems.
Rapid chlorine dioxide bleaching at intermediate consistency
has been found to be chemically feasible and appears
practical economically, using less chemicals, water, and
steam (108). Operating conditions, especially temperature
and pH, are more critical and must be controlled more
carefully. Suitable equipment is being developed for this
process and is being installed in a southern mill.
In kraft mills where prehydrolysis is practiced, as is the
case in all kraft dissolving mills, the bleachery losses can
292
-------
be reduced if the prehydrolysis step is accompanied by a
soft cook. In this case more organic matter goes to the
recovery furnace with the spent cooking liquor. In some
instances the prehydrolysate is added to the weak black
liquor as a means of disposal. Because of the low solids
content of the hydrolysate this is a relatively high cost
practice and requires that higher than normal evaporation
capacity be provided. While low in solids compared to weak
liquor, the prehydrolysate contains wood sugars and wood
acids providing an added BOD5 load if discharged to external
treatment facilities. It appears possible that membrane
processes might provide suitable fractionation of the
several components to produce by-products of value.
Prehydrolysate is used as a nutrient source for growth of
food yeasts in the USSR.
A process change for reducing high losses from the
production of sodium base sulfite dissolving pulp has been
evaluated for a southern mill (118). In simplified terms,
soda based pulp from the digester stage is drained of a
portion of the waste liquor and passed directly to the hot
caustic extraction stage without washing. After hot caustic
extraction, the pulp is washed and the wastes removed in
washing are added to the digester waste and the combined
wastes are then concentrated and burned. It is also
possible to use the concentrated caustic liquor as salt cake
make-up in the kraft process. This is expected to achieve
90 percent reduction in BOD^ and color.
Other process changes such as oxygen bleaching give promise
of reducing bleachery losses, especially with respect to
color bodies and inorganic materials, particularly
chlorides. There are indications (106) (117) that the wash
water from oxygen bleaching stages can be introduced into
the kraft recovery system since it is relatively free of
chlorides. However, magnesia is added in this process (140)
and it could result in accumulative problems in the liquor
system. A change to oxygen bleaching involves high capital
investment in the bleachery and a plant to produce oxygen
and, since other bleaching stages continue to use chlorine
compounds, not all bleach plant effluent is eliminated.
However, the existance of a mill operated oxygen production
plant, producing in excess of that needed for bleaching,
allows for other oxygen uses as black liquor oxidation or
supplemental addition to the lime kiln as required.
Laboratory studies do indicate (105) , with 100% reuse of
oxygen stage effluent, large reductions in BOD5 (81%), COD,
chlorides and color (89-92%). Such oxygen stage effluent is
evidently easily handled by conventional secondary treatment
293
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facilities as BOD5_ reductions ranging from 75-97% were
obtained employing aeration periods of 1 to 10 days. The
U.S. kraft mill with an operating oxygen bleaching system
predicts that recycling the oxygen stage effluent to brown
stock washing could result in BOD5 and color reductions of
about 60 and 90 percent respectively from the levels
produced by the conventional CEDED sequence (177). As a
further refinement on this approach, experiments have
indicated that the use of an oxygen stage alone as part of a
brown stock washing system would result in very clean
bleaching (81) and reduce BODJ> and color of total mill raw
waste load by UQ and 70% respectively obtained by a
reduction in the bleach load of 70-80% BOD5 and in excess of
90% color difference as compared to conventional bleaching
sequences.
The findings from pilot oxygen bleaching have been more
fully reported (291) and support earlier information as to
significant BOD5_ and color reductions when oxygen bleaching
is employed.
A Swedish kraft mill employing oxygen bleaching as a first
stage, has incorporated a large surge tank 510,000 1
(135,000 gal) for effluent control. By containing the
oxygen stage wash water with digester and screening system
effluent, it anticipates reducing the BOD5 load more than 50
percent and discharged color by 70 percent over conventional
systems.
It has been found (110) (111) that oxygen bleaching can also
be successfully employed as a pre-bleaching stage for
sulphite pulps. The oxygen stage is capable of delignifying
pulps to a low lignin content with simultaneous preservation
of viscosity. The advantages of the process in chemical
recovery and water pollution control are only achieved with
a sodium base cooking process in which the oxygen bleaching
stage provides a sodium make-up.
As noted in Section V, pilot plant experience indicates that
washing between stages may be eliminated by the new
displacement bleaching process and effluents reduced to the
amount of water introduced with new chemicals.
Continued progress is reported for the Rapson process
(112) (113) (11U) in which bleaching wastes concentrated by
recycling are introduced into the recovery system with the
black liquor. Chloride content of the liquor system is
controlled by evaporating white liquor to a sufficiently
high concentration to allow sodium chloride to crystalize
out (115). Total chlorides in the system are reduced by
294
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replacing most of the chlorine used in the chlorination
stage by an equivalent amount of chlorine dioxide (116).
The salt obtained can be used in the production of chlorine
dioxide by the R-4 process (117). The Rapson process has
been tested in a pilot plant and a full scale operation is
being installed at a Canadian mill. Both of these processes
are described in Section III.
Deink Subcategory
No dominant system for secondary fiber pulping and deinking
has emerged from the many different systems developed for
these processes. The significant differentiations are
whether the process is batch or continuous, hot or cold, low
consistency or high consistency, and whether it uses
countercurrent washing or flotation as the main ink
separation process.
Pulp which is still contaminated after the process should
not be discharged to the sewer but should be run over a wet
lap machine for disposal or sale to a mill capable of using
a lower grade of stock.
The flotation deinking system does not remove clay and
dissolved contaminants so it has a cleaner effluent than a
washing system. However, these contaminants appear in the
paper mill effluent unless a closed water system is used in
this area. A special solvent process is the only truly
closed system (119); the contaminant removal operation
generates no liquid effluent, and the contaminants are
discharged in a dry state. The economics of this process,
however, are such that only one small plant is in operation
in the U.S.
Data was obtained from 53 percent of the 17 mills in this
subcategory in the 1973 and 1974 surveys. Of these nine
mills, 67 percent reported using countercurrent brownstock
washing and 50 percent were found to be operating spill
collection systems. Seventy-five percent of the mills using
multistage bleaching are making extensive use of
countercurrent washing in the bleachery. Process changes
have recently been made in 22 percent of the surveyed mills
to reduce the liquid effluent.
All paper machines associated with the surveyed deinking
plants recycle white water with 66 percent using extensive
recycle and 50 percent using high pressure showers. Paper
machine savealls are used in 66 percent of these mills and
almost 90 percent of those surveyed reuse some cooling water
and vacuum pump seal water.
295
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Papermaking
Since the papermaking process is virtually identical in all
subcategories, this discussion is applicable to each of
them.
Recycling of white water within the stock
preparation/papermaking process has long been practiced in
the industry. In the last 10 years further strides in reuse
have been made. Problems associated with increased reuse
usually manifest themselves in reduced machine speed and/or
product quality. Slime growth due to increase of BODJ5 and
temperature has been encountered. This problem can be
reduced by the proper application of biocides, by better
housekeeping, and by design for higher liquid velocities in
pipelines, shorter detention time 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 limited by slime growth and scale buildup.
Combinations of temperature and dissolved solids buildup can
interfere with sizing and other chemical reactions. In
addition, corrosion is a significant factor in increased
recycling within the white water system.
Most mills employ a saveall 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. Savealls are of
three principal types. The older type consists of a screen
covered drum immersed in a vat through which the water
passes leaving a mat of fiber. This is removed continuously
for reuse directly in the manufacturing process. A number
of improved variations of this device are in use which
employ filtration through the mat of fiber. These include
the cloudy port drum vacuum filter and traveling wire
devices operating on the same principle. Second is the
newer disc type, which uses a series of screen-covered discs
on a rotating shaft immersed in the vat. The action is
similar to the drum saveall, 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 savealls 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 third type is the dissolved air flotation saveall
(DAF). In this type unit air bubbles, formed on the
dissolution of air under pressure, attach themselves to the
296
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fibers, causing them to float to the surface where a
continuous mechanical rake collects them for reuse.
The disc type saveall 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 thus preventing problems arising on reuse.
Clarified effluent from savealls is on the order of 10.43-
25.04 kl/kkg (2,500-6,000 gal/ton) (58), with a suspended
solids content of 120 mg/1 or less, whereas the influent may
contain 2398 mg/1 or more.
All or a part of the clarified effluent may be discharged
directly to an outfall sewer, but most mills reuse a
significant portion of it for such services as (58):
1. Vacuum pump seals
2. Machine showers
3. Stock cleaner elutriation
U. 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
Water showers are used in both the forming and pressing
sections of the paper machine 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-cleaning showers, however, a suspended solids
content of less than 120 mg/1 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. These presses were developed within the
last 10 years and have enjoyed increasing popularity because
of their efficiency in water removal, and lower capital and
297
-------
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.
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
rejects 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.
Rejects from the last stage have a consistency of about
three percent and are usually sewered. Well designed and
operated cleaner systems reject one-half to one percent of
the weight of the feed to the primary stage. To reduce such
losses further, elutriation water is added at the final
stage. In some cases, a closed discharge cleaner replaces
the free-discharge unit in the final stage.
Vacuum pumps are used in paper mills to provide a vacuum
source to accelerate the removal of water from fourdrinier
machines, presses, savealls, 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 and stationary parts of the pump, and is
necessary to avoid backflow of air to the vacuum side.
Water used for this purpose approximates 10.U3 to 16.69
kl/kkg (2500 to UOOO 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.
Further, it must not promote formation of scale inside the
pumps or corrode their mechanical parts, and it must be
relatively cool (typically less than 34 °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 significance of water used to seal or lubricate packings
for rotating shafts increases. These shafts are used for
pumps, agitators, refiners, and other rotating equipment.
The use of mechanical seals as an alternative has reduced
the volume of seal water, but they have so far not proven
298
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satisfactory in many applications. Reduction of seal water
usage is an area which reqiures more study and development.
In the meantime, several methods are used to minimize fresh
water requirements depending on product as well as mill
configuration. Seal water is collected and passed through
for reuse directly back to the pumps or to another water-
using system. The use of excess white water for vacuum pump
sealing, before discharge to sewer or back to process, is
also practiced. Another procedure is to use the discharged
vacuum pump water for cooling of heat exchangers.
Fine Paper Subcategory
All modern fine paper mills recycle most of the machine
waters and employ a saveall system to capture materials lost
through the fourdrinier wire (120). These employ
sedimentation, filtration, and flotation with the separated
materials being returned to the papermaking process and a
portion of the clarified water returned for stock
preparation and other uses in the paper machine system.
In the 32 percent of the 56 mills in the non-integrated fine
paper subcategory surveyed in 1973 and 1974 the most common
factor limiting water reuse was found to be product quality.
Many mills experienced a reduction in product quality when
excessive recycle produced a build-up of dirt or high
dissolved solids in the process water. Three mills are
experimenting with total recycle by using mixed media
filtration or other fine filtration processes after
conventional solids removal in a clarifier or flotation
unit.
Ninety-four percent of the mills surveyed are recycling
white water and 89 percent use savealls. Some hot water is
collected and reused in 73 percent of survey mills while
vacuum pump seal water or cooling water is reused in 44
percent of mills.
Tissue Subcategories
There are 72 tissue mills in this sufccategory and 26 percent
of them were included in the 1973 and 1974 survey. All the
mills surveyed are recycling at least a portion of machine
white water and more than 50 percent are using high pressure
showers to reduce water use. Ninety-four percent of survey
mills are using savealls to reduce effluent solids with the
flotation saveall being widely used. While the flotation
units give poor results on many effluents, this is not the
case in tissue mills where solids removal up to 90 percent
299
-------
are consistently obtained and one mill with two stages of
flotation averages 94 percent removal.
Pilot tests using a lean-water system successfully improved
the performance and increased the capacity of the saveall in
one tissue mill (121). This system involves taking rich
white water from the wire trap and feeding it onto the sheet
by means of a secondary headbox. A final white water of
lower consistency than that of conventional methods was
produced.
More than 60 percent of the tissue mills surveyed reuse
cooling water and vacuum pump seal water.
IDENTIFICATION OF BPCTCA INTERNAL TECHNOLOGY
General
In order to identify internal control procedures used to
reduce raw waste loads, a comprehensive survey program was
undertaken beginning in September 1975. In-depth data on
operating internal controls and on the potential for
additional waste reduction methods have been collected from
fifty-six (56) bleached kraft, groundwood, sulfite, soda,
deink and non-integrated paper mills. Based upon all
available data the internal controls technology representing
BPCTCA were identified. These technologies and the extent
of their application at the surveyed mills are shown on
Table 82.
A description of each of the twenty-one (21) internal
control technologies with appropriate schematic diagrams
follows. These descriptions form the bases for the internal
control costs presented in Section VIII. For the purpose of
calculating costs, controls were applied to the various
subcategories as shown on Table 83.
High Level Alarms on Tanks
High level alarms are installed on all pulp and paper mill
stock and chemical tanks. The operators are alerted as soon
as a tank starts to overflow to the sewer, so that the
duration of a spill is kept as short as possible. Tankage
will vary according to mill size and subcategory. Table 84
shows the number of alarms included for typical mill sizes.
Each paper machine has three chemical tanks and four stock
tanks. Each pulp dryer has two stock tanks.
300
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TABLE 82
BPCTCA INTERNAL ^lEASUUKS USED AT SURVEYED HILLS
(All Figures are Percentages)
NUMBER OF MILLS
Usage - Y=Yes, N=No, U=Unknown
High Level Alarms on Tanks
Use of Mill Haste Water In
Woodyard
Decker Filtrate For Sulfite
Pit Dilution or Vacuum
Washer Showers
Knot Collection Disposal
or Reuse
Turpentine Collection
Soap Collection
Prehydrolysate Disposal
by Burning
Sulfite Red Liq. Evap.
and Disposal
Counter Current Washing
for Deink
Evaporator Condensates for
Brown Stock Washer Showers
Close up Screen Room with
Reuse of Decker Filtrate
Recook Screen Room Rejects
Jump Stage Countercurrent
Hash in Bleach Plant with
Reuse of Chlorination
Filtrate
Use of CL02 Haste Acid For
Tall Oil Mfg.or Add to Bl.
Liq. for Recovery
Reuse Kiln Scrubber Water
Use of Green Liq. Dregs Filter
Evaporator Condensate for
Causticizing Make-up
White Water Showers for
Wire Cleaning
White Water Storage for
Upsets S Pulper Dilution
Broke Storage & Overflow Prev. 50-38-12
Install Saveall
(1) Screen Room Close-up is not considered BPCTCA for kraft but vany of those wills report that their screen rooms are closed.
Key: GWD * Groundwood-Cherai Mechanical, Groundwood-Therrno Mechanical, Groundwood-Fine, Groundwood-CMN: BKD =• Bleached Kraft-Dissolving;
BKM - Bleached Kraft-Market; BKP = Bleached Kraft-BCT, Bleached Kraft-Finer SO = Soda; DI = ne,tnk; HF - %>n Integrated-Tissue,
Non Integrated-Tissue (FWP): DS = Dissolving Sulfite; PS = Paper Grade Sulfite-Blow Pit Wash, Paper Grade Sulfite-Drum Wash,
cm
8
Y-N-U
12-38-50
63-25-13
50-38-12
75-25-0
«KD
2
Y-'i-?r
50-50-0
100-0-0
0-100-0
mo-o-o
100-0-0
100-0-0
100-0-0
] 00-0-0
0-50-50
100-0-0
100-0-0
100-0-0
100-0-0
100-0-0
0-50-50
BKM
6
Y-N-U
67-33-0
50-33-17
33-50-17
100-0-0
33-50-17
50-50-0
17-83-0
50-17-33
(1)
33-33-33
67-33-0
83-17-0
67-33-0
67-33-0
50-33-17
50-17-33
BKP
18
Y-M-II
72-0-28
28-39-33
33-39-28
72-0-28
44-28-28
50-22-28
22-39-39
44-22-44
(1)
56-11-33
39-39-22
50-28-22
28-39-33
28-39-33
39-33-28
50-22-28
28-0-72
44-6-50
89-0-11
SUBCATEGORY
SO DI SF NT DS
13543
Y-N-T1 Y-N-U Y-N-lt Y-N-U Y-N-U
0-100-0 33-0-67 60-0-40 50-25-25 67-33-0
100-0-0 0-100-0
0-100-0 67-0-33
100-0-0 33-67-0
100-0-0
67-33-0
100-0-0
100-0-0 0-50-50
0-100-0
0-100-0 33-67-0
0-100-0
0-100-0 67-33-0 80-0-20 100-0-0
100-0-0 67-33-0 40-20-40 100-0-0
100-0-0 100-0-0 80-20-0 75-0-25
100-0-0 100-0-0 100-0-0 100-0-0
PS
6
Y-N-U
67-33-0
17-50-33
17-67-17
100-0-0
100-0-0
67-0-33
50-33-17
50-50-0
17-33-50
33-33-33
100-0-0
-------
TABLE 83
INTERNAL CONTROL TECHNOLOGY USED FOR BPCTCA COST ANALYSIS
(X Denotes Usage)
GWD BKD BKM BKP SO DI NF NT DS PS
High Level Alarms on Tanks
Use of Mill Waste Water in Woodyard
Decker Filtrate for Sulfite Pit
Dilution or Vacuum Washer Showers
Knot Collection Disposal or Reuse
Turpentine Collection
Soap Collection
Prehydrolysate Disposal by Burning
Sulfite Red Liq. F.vap. & Disposal
Counter Current Washing For Deink
Evaporator Condensates for Brown
Stock Washer Showers
Close up Screen Room with Reuse of
Decker Filtrate
Recook Screen Room Rejects
Jump Stage Countercurrent Wash
in Bleach Plant with Reuse of
Chlorination Filtrate
Use of CL02_ Waste Acid for Tall
Oil Mfg. or Add to Bl.Liq.
for Recovery
Reuse Kiln Scrubber Water
Use of Green Liq. Dregs Filter
Evaporator Condensate for
Causticizing Make-up
White Water Showers for
Wire Cleaning
White Water Storage for Upsets
& Pulper Dilution
Broke Storage & Overflow Prev.
Install Saveall
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
X XX
X
X
X
X
X X
XXX
XXX
XXX
X
X
X
X
X
X
X
X
X
X
Key: GWD = Groundwood-Chemi Mechanical, Groundwood-Thermo Mechanical, Groundwood-
Fine, Groundwood-CMN; BKD = Bleached Kraft-Dissolving; BKM = Bleached Kraft -
Market; BKP = Bleached Kraft-BCT, Bleached Kraft-Fine; SO = Soda; DI = Deink;
NF = Non Integrated-Tissue, Non Integrated-Tissue (FWP); DS = Dissolving
Sulfite; PS = Paper Grade Sulfite-Blow Pit Wash, Paper Grade Sulfite-Drum Wash.
302
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TABLE 84
MILL SIZE (USED FOR COST ANALYSIS)
oo
o
Subcategory
1. Groundwood: Chemi Mechanical
2. Groundwood: Thermo Mechanical
3. Groundwood: CMN
4. Groundwood: Fine
5. Bleached Kraft: Dissolving Pulp
6. Bleached Kraft: MKT
7. Bleached Kraft: BCT Papers
8. Bleached Kraft: Fine
9. Soda
10. Deink
11. Mon Integrated Fir.e Paper
12. Non Integrated Tissue Paper
13. Non Integrated Tissue Paper (FWP)
14. Dissolving Sulfite Pulp
15. Paper Grade Sulfite: Blow Pit Wash
16. Paper Grade Sulfite: Drum Wash
Very Small
Tons No. No.
Day Mach. Alarm
15
15
Small
Tons
Day
100
100
75
150
250
250
80
30
35
35
160
160
No.
Mach.
2
2
2
2
2
5
3
2
3
3
3
3
No.
Alarm
11
11
11
11
36
48
18
8
12
12
23
23
Tons
Day
300
300
150
300
600
350
670
670
300
230
100
110
110
550
550
550
Medium
No. "
Mach
3
3
2
3
1
1
3
5
2
3
2
3
3
1
7
7
No.
Alarm
15
15
11
15
30
28
40
48
36
18
8
12
12
13
39
39
Tons
Day
600
600
500
550
1000
700
1300
1300
700
500
280
450
450
Large
No.
Mach.
4
4
3
5
2
2
4
9
5
5
5
5
5
No.
Alarm
22
22
18
15
44
30
56
76
48
26
20
20
20
-------
Use of Mill Wastewater in Woodyard (Figure
This system consists of facilities to utilize bleach plant
effluent, namely caustic effluent, for woodyard operations.
Caustic effluent will be used for flume makeup, washdown
hoses and wood showers. Flume water is recycled with a
traveling screen removing floating material and a grit
system to remove heavy materials. Showers on the traveling
screen utilize caustic effluent. This system is based on
dry barking, however, if a wet drum is used caustic effluent
should also be used in the drum.
A level control in the flume actuates two control valves on
the caustic effluent line coming from the bleach plant.
When level in the flume is low the valve on the caustic line
to the sewer will close and the valve on the line to the
flume will open. If no caustic effluent is available, flume
level will be maintained by a manually controlled fresh
water line. The same is true for showers on the traveling
screen and on hoses.
Decker Filtrate For Sulfite Pit Dilution or Vacuum Washer
Showers (Figure 45)
This system uses the decker filtrate from the decker seal
tank to wash the brown stock in the blow pit and then
dilutes it to about 3% so it can be pumped to the screen
room. This system also includes a storage tank in which the
effluent from the end of a blow pit wash (the cleanest
effluent) is stored and used for the first part of the next
wash. This serves two purposes. First, it reduces the
amount of filtrate required for washing by about 4.17 kl/kkg
(1,000 gal/ton). Secondly, it increases the solids content
of that portion of the effluent going to the evaporators,
thus reducing solids going to the sewer.
This system operates on an entirely batch basis in which
five (5) steps are involved. These are as follows:
1. The brown stock is washed with recycled wash from the
last part of the previous wash and the effluent is sent
to the evaporators.
2. The pulp is then washed with decker filtrate and the
effluent is sent to the evaporators.
3. The pulp washing continues with decker filtrate and the
effluent sewered because evaporator capacity to handle
the low solids wash water is impractical.
304
-------
CAUSTIC
SEAL
TANK
r'
WOODYARD
SUPPLY
TANK
FRESH WATER.
HOSES
FRESH
WATER
l
NEW
EXISTING
1
I
i !
V V
SHOWER
SUPPLY
|
-
OJ
o
in
* /
>y / r-
TRAVELING J A
SCREEN ;' /
I
-1J-— -
-rf— -
/ i
-y/ xX
y' *
1 /
FLUME
*l
«!
S1
x-
r—^
CIRCULATING
PUMP
WASTE WATER USE IN WOODYARD
FIGURE 44
-------
CO
o
PULP FROM
DIGESTER
BLOW PIT
DECKER DRAIN
PUMP
, J
-0x3-
L.
NEW
EXISTING
RECYCLE
WASH
WATER
TANK
-fxl-
.TO EVAPORATOR
VIA STORAGE TANK
DECKER FILTRATE FOR BLOW PIT WASHING
FIGURE 45
-------
4. The pulp washing continues with decker filtrate and the
effluent is sent to the storage tank.
5. The pulp is then diluted and pumped to the screen room.
Knot Collection and Disposal or Reuse (Sulfite) (Figure 46)
This system collects the rejected knots at the brown stock
knotters, washes them to remove any recoverable fiber,
drains and conveys them to a waste bin for storage until
they can be trucked away to landfill. As an alternate they
can be conveyed directly to the hog fuel system.
The system will consist of:
1. A chute from the knotter to a dewatering screen.
2. A drainer where the knots are washed by showers using
weak black liquor from the third stage brown stock
washers.
3. A filtrate tank where the drainer filtrate is collected
to be pumped to the interstage repulper between second
and third stage brown stock washers.
U. A 100-foot belt conveyor to carry the knots to a second
chute which will drop them into a bin to be stored until
they can be trucked to landfill or sent to the hog fuel
boiler.
Knot Collection and Recooking (Kraft) (Figure U6)
The knot recook system is almost identical to the knot
disposal system proposed for sulfite mills. The only
difference being that in this system the knots, after being
washed to remove the loose fiber are conveyed to a chip bin
or onto a chip conveyor. It is assumed that the conveyor
needed for this is the same as the one proposed for the
disposal system, thus the cost estimates for the two systems
are identical.
Turpentine Collection (Figure 47)
The turpentine system utilizes the gas condensate which
would be going to sewer from the existing heat exchanger on
digester relief piping which is a part of the heat recovery
system.
Turpentine is collected in a tank providing for ten days
production. A pump and piping is provided to fill a
307
-------
KNOT COLLECTION & RECOOKING OR DISPOSAL
FROM BLOW TANK
KNOTTER
'I
>L
^ WBL FROM 3— STAGE BROWN WASHER FILTRATE TANK
DRAINER
ir STOCK TO BROWN STOCK WASHERS
TO INTERCHANGE REPULPER BETWEEN
2— a 3— STAGE B.S. WASHERS
CONVEYOR
-NEW
EXISTING
WASTE
DISPOSAL
(SULFITE)
I I
I t
r—J L-
I
1 CHIP
| BIN
I (KRAFT)
I
L
303
FIGURE 46
-------
CO
o
10
FROM DIGESTER
WATER
-CXh
DECANTING TANK
.1
VENT
FLAME ARRESTER
SEPARATOR
TURPENTINE
STORAGE TANK
SEAL LEG
KILN
VENT
FRESH WATER SUPPLY
TO R.R.
TANK CAR
OR TANK TRUCK
X
-CXh
TRANSFER PUMP
TURPENTINE RECOVERY SYSTEM
•NEW
EXISTING
FIGURE 47
-------
railroad tank car or tank truck. The raw turpentine is
shipped to a turpentine distillation plant.
The complete system consists of a decanting tank, collection
tank, and pump. The decanter is vented through a separator,
flame arrester, with the vented gas turned in the lime kiln.
Soap Collection (Figure 48)
Soap is collected from 28% solids black liquor from the
third evaporator effect to a soap settling tank, which is
sized for one hour retention. Another pump returns black
liquor from the bottom of the retention tank to the fourth
evaporator effect. Soap is skimmed from the top of the
retention tank and pumped to a soap collection tank. A
second pump delivers soap to the mill tall oil system or to
commercial transport for sale. A small tank and soap pump
are used for skimming soap from the top of the weak liquor
storage tanks and pumping it to the settling tank.
Prehydrolysate Disposal by Burning
Each system is unique and includes proprietary information.
Therefore, the system used to arrive at the cost estimates
will not be described.
Sulfite Red Liquor Evaporation and Disposal (Figure U9)
Sulfite liquor is evaporated and stored for disposal. The
system is applicable to soluble base sulfite mills, namely
those mills using Na, Ng, or NH_3 base liquors. Ca base
liquor would scale conventional multiple effect evaporators.
The system collects weak red liquor from existing vacuum
washers at 12% solids. Four hours storage is provided. The
liquor is evaporated in a set of five body four effect
evaporators to a solids content of 50% in the 454 kkg (500
tons) per day model mill. The concentrated liquor can then
be sold or incinerated. A mill with blow pit washing would
have to install an extra evaporator effect.
Counter Current Washing For Deink (Figure 50)
By addition of a heat exchanger, and adequate storage with
related pumps and piping the first stage washer filtrate is
used for deink pulper dilution. This control assumes that
clarified paper machine white water is being used on the
third stage deinked unbleached pulp washer. The heat
exchanger is required to heat the first stage filtrate for
use in deink pulping. Common washing techniques would use
310
-------
NEW
EXISTING
WEAK
LIQUOR |
STORAGE
I MULTI - !
!EVAPORATOR I
X
-EX-
-{xj
SETTLING
TANK
-M-
LOADING
PUMP
-{XJ-
-CXh
COLLECTION
PUMP
TO TANK CAR OR
>
TALL OIL SYSTEM
SOAP COLLECTION SYSTEM
FIGURE 48
-------
CO
»—'
rsi
STEAM
5 BODY - 4 EFFECT
EVAPORATORS
COMBINED
CONDENSATE
T
to
Q-
CONCENTRATED
RED LIQUOR
STORAGE
— 0
— T-IX3-4— 1
, _ r
CLEAN
CONDENSATE
O
i—xj
COOLING
WATER
I 1
FIRST RED !
STOCK WASHES'
SEAL TANK
1
STEAM
'WARM WATER
CONDENSATE
TO DISPOSAL
OR INCINERATOR
NEW
EXISTING
VENT
SULF1TE RED LIQUOR EVAPORATION
FIGURE 49
-------
TO PULPER
DILUTION
SCREEN
WHITE WATER FROW
rf
I PAPER MACHINE
! STOCK
I
I
SCREE
DILUTION
>
FROM
t-JIMG
NEW -
EXISTING ---
DE-i'MK fv'ilLU; UMSLEACHED STOCK COUNTER-CURRENT WASHING
FIGURE 50
-------
sidehill screens or gravity drums however this control would
be compatable with any style.
Evaporator Condensate for Brown Stock Washer Showers
(Figure 51)
It is recognized that there is not enough digester and
combined evaporator condensate for both causticizing and
brown stock washer requirements. Causticizing requirements
will utilize condensate from evaporator effects two, three
and four. Effects five and six and surface condenser
condensate will be available for brown stock washing. In a
seven effect evaporator train, the first body may be split
into two effects, with steam to these effects being
condensed as clean condensate and pumped back into the
boiler condensate return system.
In this system, condensate for brown stock washer showers
for a model mill of 363 kkg (UOO tons) per day will be
available as follows:
No. 5 effect U.1 I/sec (65 gpm)
No. 6 effect a. 5 I/sec (72 gpm)
Surface condenser 5.7 I/sec (90 gpm)
Digester blow condensate U.2 I/sec 167 gpm)
Total 18.5 I/sec (294 gpm)
Additional flow make-up will be required. This may come
from decker filtrate and/or.fresh water.
The system consists of a facility for approximately four
hours of combined condensate storage; pumping systems to
deliver the flow to storage (assumed to be available when
developing the costs presented in Section VIII) and from
storage to the washer showers; conductivity monitoring and
control systems to sewer condensates which may become
contaminated with black liquor; and alarm systems to allow
transfer to fresh water when condensates are unavailable for
use on the washers.
Close Up screen Room With Reuse of Decker Filtrate (Figure
52)
The model mill to which this control was applied operated by
sewering secondary cleaner and screen rejects. In closing
up the screen room, a third stage of cleaning was added and
the existing atmospheric screens were replaced with pressure
screens. The equipment required to refine the secondary
screen rejects and return them to the „ secondary screen is
314
-------
BLOW STEAM CONDENSATE FOR BROWN STOCK WASHER SHOWERS
FROM SURFACE
CONDENSER
FROM DIGESTER
BLOW CONDENSER
FW MAXE-UP
?*w *
CO
I—'
01
vy
CONOENSATE
STORAGE
TANK
FRESH WATER SUPPLY
i 1 HEATER
I L 1
CONOENSATE
—**4zJc»
*4-
CONDENSATE PUMP
EVAPORATOR CONOENSATE NOT
USED IN CAUSTICIZING
STEAM
1-f.
V
I
l
/ r •
' /
/
LAST STAGE
BROWN STOCK WASHER
•NEW
-EXISTING
FIGURE 51
-------
SCREEN ROOM CLOSE-UP
CLEANERS
PRIMARY SECONDARY] TERTIARY
WATER
316
FIGURE 52
-------
included. The new screens are located on a new mezzanine
inside the existing building. A new primary screen supply
pump is also included.
Recook Screen Room Rejects (Figure 53)
The proposed system will take secondary screen rejects which
were previously assumed to be sewered, and pass them over a
rejects drainer. The dewatered rejects will then be
conveyed to and deposited in the chip hopper to be recooked
in the digester.
The system as described would find application in a bleached
kraft mill. In sulfite mills it is considered undesirable
to recook screen rejects for quality reasons, so in these
mills the screen rejects could be dewatered and conveyed to
an appropriate location to be picked up and hauled to
landfill. The capital cost for a system to dewater and
recook or for a system to dewater and haul to landfill is
the same.
In groundwood manufacture the refining of screen room
rejects is a part of the pulping process and will not be
considered a separate internal control. None of the
groundwood mills visited during the surveys were sewering
screen rejects.
Jump Stage Counter Current Wash in Bleach Plant with Reuse
of Chlorination Filtrate (Figure 54)
The filtrate from the second chlorine dioxide washer will be
used on the showers for first chlorine dioxide washer and
the filtrate from the first chlorine dioxide washer will be
used on the showers for the chlorine washer. The filtrate
from the second caustic washer will be used on the first
caustic washer. Jump stage instead of straight
countercurrent washing is necessary if the first and second
caustic washers are either 304 ss or rubber covered (less
corrosion resistant than 317 ss).
The model mill is a 726 kkg (800 tons) per day bleached
kraft mill with two bleach plants.
A displacement ratio of 1.2 to 1 was used on all washers.
Consistency of mat leaving the washers is 12% A.D. Filtrate
from the chlorine washer is used for dilution after brown
stock decker. Inlet washer vat consistency is 1% A.D.
System was costed on the basis of new pumps being installed
for the countercurrent flows.
317
-------
DECKER
FILTRATE
NEW
EXISTING
CO
I—»
OD
^-1 SECONDARY
/' -\ SCREEN
• -X-.
{ 1
1 1
i I
PRIMARY |
REJECTS 1
j i
REJECT "
DRAINER
~-^
^
T
TO UNSCREENED
STOCK CHEST
CHIPS
RECOOK SCREEN REJECTS
FIGUREv 53
-------
JUMP STflGE COUNTERCURRENT
WASHING IN BLEACH PLANT
00
FIGURE 54
-------
CLO2 Waste Acid Use (Figure 55)
This system consists of one pump and piping from the
plant to the tall^oil acid storage tank and the weak black
liquor tank. Mills'which make tall oil could use some but
probably not all of the waste acid for that purpose. The
waste acid not used in making tall oil can be added to the
weak black liquor storage tank. Care must be taken to
insure adequate dilution of waste acid by the weak black
liquor.
The system estimated was for a 363 kkg (400 tons) per day
mill using part of the waste acid in making tall oil and the
balance in the weak black liquor.
Reuse Kiln Scrubber Water Process Description (Figure 56)
In this system the waste water from the kiln scrubber is
pumped to either the lime mud washer or to the lime mud
storage tank. In both cases the lime dust taken out of the
air by the scrubber is recycled rather than sewered. The
basis used is 1.1 1(0.3 gal) per minute of scrubber water
for each daily ton of production.
Use of Green Liquor Dregs Filter (Figure 57)
The dregs from the green liquor clarifier is pumped to a
vacuum filter. The solids from the filter is disposed of in
landfill and the filtrate will go back to the weak wash
tank.
The costs were estimated for the following conditions:
1. The existing green liquor dregs pump is used to pump the
dregs to the filter.
2. The filter is installed on a fabricated steel stand
inside the existing lime kiln building.
3. The solids are collected in a dumpster and hauled to
landfill.
4. The filtrate is pumped back to the weak wash tank.
Evaporator Condensate For Causticizing Makeup (Figure 58)
Evaporator condensate from the second, third, and fourth
effects are pumped to a holding tank for use in the
causticizing and lime recovery area. Evaporator condensate
is used at the kiln scrubber, lime mud dilution from
320
-------
GO
PO
ZL.
WEAK BLACK
LIQUOR
TANK
ZL
ACID '
STORAGE '
TANK [
I
CL02
WASTE
ACID
STORAGE
TANK
NEW
EXISTING
CHLORINE DIOXIDE V/ASTE ACID USE
FIGURE 55
-------
oo
ro
NEW
EXISTING
LIME KILN
LJ
I
-X
SCRUBBER
I I
I I
-LJ
! 1
FROM W.L. CLARIFIES
r
I I
MUD WASHER
I i
L. ,___,
I TO WK. LIQ. STORAGE
I
I
TO MUD TANK
KILN SCRUBBER WATER
FIGURE 56
-------
GREEN LIQUOR DREGS FILTER
OJ
ro
CO
1 1
GUf BN —••fr'wWB.*
1 LIQMOt |-vn-
I
aARIFIE* 1
no. i !
~l_— £\ — ^
1 1
GREEK 1
LIQUOR 1
' |
1
| CtARIFIER
NO. 2
>««*'
SEAL WATER
fxi
db
H-C
n
1 1
* i
i
j.
"
i
rt
X"*X
"^*a
( ) jo ycnK
X — ' WASH TA
SEPARATOR
DREGS
MIXER
r — i LEGEND
I— p-J - , NEW
I I EXISTING
1 DREGS 1
1 WASHER '
| TO SEWER
TO FILTER
HOOD EXHAUST
£~
\i \
i»<^~^
^ ® I/ « \
DREGS
""*" ULIER
UK • | TO LANDFILL
/
-------
EVfiPQRATQR COMPENSATE USED FOR CAUSTICIZING MAKE-UP
5
o
1A
ri ri n ri n
: . . i : ! ;
• • i «
It »1 ..... * I * I *' '
: : ,' .
" ' I
r4 1r\, j
iMM.MM.n
v 4 V ' •...-•
L
-Hr-
CONDEMSATE
STORAGE
324
r
I NOT
! MCUL
TO LIME MUD
STORAGE
TO VE»TU»»
SCSUBIEB
TO WO
FILTER
TO D9CGS
MSMCR
TOMUD
WISMEK
TO SLAKE*
CLASSIC IE*
L E 6 C • 0
NEW
FIGURE 58
-------
storage, mud filter shower, dregs filter showers, and mud
washer dilution. A conductivity probe is used to detect
liquor carry over so that black liquor is kept out of the
causticizing and lime recovery system. The holding tank
uses fresh water for low level control.
Paper Machine White Water Showers For Wire Cleaning (Figure
59)
Clarified white water from the paper machine containing low
additives and fillers, allows installation of self cleaning
white water showers. In this system the white water would
be used for fourdrinier showers. The system includes a
white water supply pump, and supply piping and showers. A
fresh water backup supply header is provided, with controls
for introduction of fresh water in event of low pressure in
the white water line.
White Water Storage For Upsets and Pulper Dilution (Figure
60)
This system consists of a storage tank to hold the white
water which over flows from the existing white water tank
and from the cloudy side of the saveall seal tank.
The white water from this tank is used in the pulper. The
tank was sized to hold white water needed for pulping, white
water needed for dilution after pulping, plus a safety
factor of 50%.
The cost estimate is based on a 45 kkg (50 tons) per day
paper machine in a non-integrated fine paper mill using a
1,816 kg (4,000 Ibs) per batch pulper. A non-integrated
mill may need a system for each machine since each machine
usually has its own saveall and depending on the variability
of furnish may have its own pulper.
Broke Storage and Overflow Prevention (Figure 61)
A broke storage system in most cases will be required for
each machine. In some instances where machines run the same
grades one system may be used for more than one paper
machine, but this case would be the exception rather than
the rule.
This system consists of a tank large enough to handle 30
minutes production of wet broke at a consistency typical of
broke from the couch. The broke tank will supplement the
existing broke system which may become overloaded because of
a grade change break. When the system settles the wet broke
325
-------
CO
ro
FOURDRINIER SHOWERS
O
NEW
EXISTING-
O
XXX
FRESH WATER SUPPLY-
ix] 1
CLARIFIED
WHITE
WATER
CHEST
WHITE WATER SHOWERS FOR WIRE CLEANING
FIGURE 59
-------
SAVE - ALL
NEW ! •
EXISTING
ro
L
PAPER MACHINE ]
1
I
1
1 "
r ' -, OVERFLOW
i EXISTING J 1
1 WHITE WATER j X
! STORAGE TANK! |
T
i
i
i
.-!-.<• -J
I ' % 1
1 IT \ |
I ' \ 1
L j _ \ i
/ ^
i
!
r- [ T -, OVERFLOW r ^
! 1 ^ 1 -^r j PULPER , J
I CLOUDY J CLEAR , | t
! SIDE ' SIDE ! Ns /
[_ ]_ J \ /
SEAL TANK '
*•
r y
L A
p -iQVERFUOW
NEW —i 1
WHITE WATER ^LS) "^
fc STORAGE TANK _J
— p
,_--
_ fcx3 £-*• I
V^HITE WATER STORAGE FOR UPSETS AND PULPER DILUTION
WHITE WATER
TRANFER PUMP
FIGURE 60
-------
NEW
EXISTING
AGITATOR
FROM PAPER MACHINE
00
ro
oo
TO PULPES
EXISTING
BROKE
STORAGE
TANK
1
1
!«
1
1
1
1
1
I
\
NEW BROKE
STORAGE TANK
BROKE STORAGE AND OVERFLOW PREVENTION
FIGURE 61
-------
can be pumped back into the existing system through the same
line.
The model mill for this system is a 91 kkg (100 tons) per
day machine making fine paper. The consistency of the broke
is 3.5%. The required storage capacity of this system is
49,200 1 (13,000 gal).
Install Saveall (Figure 62-65)
To properly cover all of the affected subcategories with
accuracy, estimates were prepared for the installation of
vacuum disc filters on tissue machines, newsprint machines,
and board machines. Two tissue machine saveall estimates
were prepared. Some of the smaller machines may install
deckers since the cost would be considerably less and there
may not be room for a vacuum saveall; however, all of the
estimates are based on disc filters.
Most of the savealls being installed today are vacuum disc
filters. It was noted, however, that more than half of the
savealls on fine paper machines in the mills surveyed were
flotation savealls. For this reason, flotation savealls
were included in the development of model fine paper mills.
EXTERNAL TECHNOLOGIES
External technologies are those processes which are employed
after the effluent leaves a mill for the reduction of
suspended solids, BOD5_, etc. before it enters the receiving
waters. These technologies are described in terms of their
general application in the industry. Subsequently, use of
these technologies by mills in the various subcategories is
discussed, followed by a discussion of the detailed design
criteria used for developing the costs which are presented
in Section VIII.
Removal of Suspended Solids
Screening is always necessary to remove trash materials
which could seriously damage or clog treatment equipment.
Automatically cleaned screens, operating in response to
level control, are commonly employed and generally represent
preferred practice. Screens are particularly useful for
barking and wood washing effluents.
The physical process of removing suspended organic and
inorganic materials is accomplished by sedimentation (with
or without flocculants or coagulants), flotation, or
filtration.
329
-------
CO
CO
o
PAPER MACHINE
VACUUM SAVEALL
ALTERNATE I
DISC SAVEALL
L E G E » D
NEW
EXISTING
FROM DRY END REPULPER
I "if "
il
BLEND
CHEST
SWEETENER
i
COUCH !
PIT
FIGURE 62
-------
PAPER MACHINE
VACUUM SAVEALL
ALTERNATE I I
DISC SAVEALL
FIGURE 63
-------
PAPER MACHINE
VACUUM SAVEALL
ALTERNATE I I I
DISC SAVEALL
GO
GO
ro
1 \
f 1
h *
ft*C\.._ £*|
L>< ? 1
\^_S ' • '
1 LOW PRESSURE ^,
\ HIGH FBFSSurfr -r ;
I FRESH (
V WATER '
X—
L E G E H
NEW
EXISTINO
FROM DRY END PULPER
SWEETENER
I
CLOUDY
WHITE
Oil
COUCH /
PIT
FIGURE 64
-------
PAPER MACHINE FLOTATION SAVEALL
CO
CO
CO
DILUTION
MATER
COAGULANT AID
fWf
MILL WATER
WHITE
WATER
CHEST
•m
C )
^>>
FLOTATION
o
COMPRESSED AIR
S SAVEALL /•% .x-
r \ *^
X*
f ~~\
VL ^x
f NORHALLt-«0» SPM
TAILINGS
SCREENS
Sl
m||FROM WIRE PIT
Sg .
iS ' FLAT MI
'£ ! SEAL TANK
TO HACMINE
\-/ I
FIGURE 65
-------
Sedimentation can be accomplished in mechanical clarifiers,
flotation units, or sedimentation lagoons. Although the
latter enjoyed widespread use in the past, the large land
requirement coupled with inefficient performance and high
cost of cleaning has made them less popular in recent years
(5).
The most widely used method for sedimentation of pulp and
paper wastes is the mechanically-cleaned quiescent
sedimentation basin (5). Large circular tanks of concrete
construction are normally used with rotating 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.
Dissolved air flotation has been applied to effluents from
pulp and paper mills and has achieved removal efficiencies
of up to 98 percent of the suspended solids (123). The
relatively high cost of flotation equipment, however, along
with its requirements for flocculating chemicals, high power
requirements, and its mechanical complexity make it
unsuitable for application in other than the capacity of a
saveall, except where space is at a premium. Its ability to
handle high concentrations and shock loads of solids is
somewhat limited. It normally is not efficient on wastes
containing pigments, fillers, or fines. Because of the
blinding and plugging nature of pulp and paper wastes, fine
screens, micro-strainers, and pressure filters are not
commonly used for suspended solids removal. Adequate
screening systems cost approximately the same as an
equivalent clarifier and have more inherent problems (124).
Because of the biodegradable nature of a portion of the
settleable solids present in the effluent of these mills,
clarification results in some BODJS reduction.
Reduction of BOD5
BODji reduction is generally accomplished by biological means
because of the relative biodegradability of most of the
organic substances in the waste except lignin. Advances in
reducing internal chemical losses and recycling have removed
most of the factors which interfere with biological
activity.
334
-------
Currently, the most common biological treatments used in the
pulp and paper industry include the use of large storage
oxidation basins, aerated stabilization basins, and the
activated sludge process and modifications thereof.
Biochemical oxygen demanding materials can be precipitated
from most pulp and paper mill wastes by the use of
coagulating chemicals but the percentage reduction obtained
is small compared to that obtained in biological treatment.
The principal benefit obtained from biological treatment is
to avoid depletion of dissolved oxygen in receiving waters.
Fish are particularly sensitive to depressed levels of
dissolved oxygen, as are many other forms of aquatic life.
Other benefits include the destruction of toxicity to
aquatic life (125) reduction in foaming tendencies (126),
and reduction of turbidity-producing inorganic coating
additives. High degree treatment also eliminates the
tendency of pulping effluents to stimulate slime production
in receiving waters (55). Biological treatment fails to
remove color since color bodies are not oxidized and at best
only a fraction of them are absorbed into the biomass.
There is generally a slight decrease in color levels through
biological treatment.
The first type of biological treatment adopted in the
industry was storage oxidation. This consists of large
natural or man-made basins of various depths which rely on
natural reaeration from the atmosphere. Since storage
oxidation is a relatively low-rate process, large land areas
of suitable topography and remoteness from dwellings are
required, making it unsuitable for many locations. Because
of the availability of land, most oxidation basins are found
in the southern states.
It is imperative that settleable solids be effectively
removed ahead of these basins since if they are deposited
therein they will decompose and add a large BOD5_ load to the
waste water.
BOD5_ loadings for which these basins are designed are from
56 to 67 kg/ha surface area/day (50 to 60 Ib/ac/day).
Retention times range from 20 to over 60 days.
This method of treatment has two principal advantages. It
is capable of handling (buffering) accidental discharges of
strong wastes without upset and has no mechanical devices
with inherent maintenance problems. Thus they perform well
on a continuous basis. Generally, this method also
accomplishes significant removal of suspended solids.
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Aerated Stabilization Basins
The aerated stabilization basin, as used in all
subcategories, evolved out of the necessity of increasing
performance of existing oxidation fcasins due to increasing
effluent flows and/or more stringent water quality
standards. Induced aeration provides a greater supply of
oxygen and allows a substantial reduction of retention time
over the oxidation basin. To fully realize the potential of
this method nitrogen and phosphorus nutrients must usually
be added since most pulp and paper effluents are deficient
in these elements. These additions are usually made in the
form of ammonia and phosphoric acid. The longer the
retention period of the waste undergoing biological
oxidation, the lower the nutrient requirement. Eight to 10
days retention and frequently up to 15 days are commonly
used in order to obtain BOD5_ levels which are less than 30
mg/1 (127) (128) (129). The specific detention time used
depends upon the characteristics of the waste waters to be
treated.
Aeration is normally accomplished using either gear-driven
turbine type surface aerators or direct-drive axial flow-
pump aerators. Diffused air can te employed but is less
efficient. Recently a downflow bubble aerator has been
developed for use in deep basins. Oxygenation efficiencies
under actual operating conditions range from 0.61 to 1.52 kg
of oxygen/kw/hr (1.0 to 2.5 Ib of oxygen hp/hr) 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 (130) (131). It is necessary
to maintain a dissolved oxygen (DO) level of 0.5 mg/1 in the
basin to sustain aerobic conditions.
BOD5_ and suspended solids levels, oxygen uptake, and
dissolved oxygen levels throughout the basins are related to
aerator location and performance and basin configuration.
There have been extensive studies of (132) eleven existing
basins which have developed aids for the design of future
basins.
Some sludge accumulates in the bottom of these basins but is
relatively inert and can be removed with periodic cleaning.
Sludge accumulation diminishes as the detention time and
degree of mixing within the basin increases. At some mills
a settling basin or clarifier follows the aeration unit in
order to improve effluent clarity.
Aerated stabilization basins provide a high degree of BOD5_
reduction without very extensive land use in comparison with
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natural oxidation basins and at capital and operating costs
lower than those for highly accelerated oxidation processes.
Activated Sludge
The activated sludge process is similar to the ASB except
that it is much faster, usually being designed for four to
eight hours of total retention. The biological mass grown
in the aeration tanks is settled in a secondary chamber and
returned to the aeration tanks, building up a large
concentration of active biological material. Since there
are approximately 3000-4000 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, oxidation is much
more rapid. Loadings in excess of 1.6 kg of BOD5/cu m (100
Ib of BOD5_/1000 cu ft) of aeration capacity per day are
obtainable, allowing the use of relatively small aeration
tanks. Since biological organisms are in continuous
circulation throughout the process, complete mixing and
suspension of solids in the aeration basin is required.
Mechanical surface aerators similar to those used in aerated
stabilization basins are normally used although diffused air
is used in some cases.
Rates of about 24,445 1/day/sq m (600 gal/day/sq ft) are
used for the secondary clarifier settling the activated
sludge. The waste activated sludge is the major difficulty
of this process as it is extremely slimy and must be mixed
with more freely draining materials such as primary sludge,
bark, or fly ash before it can be successfully dewatered.
Experimental work employing centrifugal thickening and heat
treatment is now underway in the hope of finding a solution
to this problem. Carry-over of suspended solids has also
been a problem with this process.
Short detention times and low volumes make the activated
sludge process more susceptible to upset due to shock loads.
When the process is disrupted, several days are usually
required to return the biological activity and high BOD5_
removal rates back to normal. Thus, particular attention is
required to avoid such shock loads in mills utilizing this
process. The greater shock load tolerance of aerated
stabilization basins, lower nutrient requirements, reduced
sludge handling problems, and lower cost, explains their
general popularity. Exceptions occur particularly where the
high cost or unavailability of land dictates the use of the
activated sludge process with its much lower land
requirements.
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The contact stabilization process is a variation of
activated sludge in which two aeration steps are used 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
conventional activated sludge is used at most other mills.
Another form of the activated sludge process uses high
purity oxygen for oxygenation within a closed activated
sludge tank. Pilot plant studies (133) indicate that such
plants can operate at very high active sludge levels (5000-
7000 mg/1) at high dissolved oxygen concentrations (greater
than 5 mg/1) with high overall utilization of oxygen feed
gas (greater than 90 percent) and give BOD5_ reductions to
levels frequently less than 30 mg/1. The amount of
secondary sludge produced is reported to be less than is
generated by conventional activated sludge and can be
successfully dewatered on a vacuum filter at low primary to
secondary ratios and low feed consistencies without chemical
conditioning.
Mill 124 operates the first such system in the pulp and
paper industry.
Ditch Aeration
The oxidation ditch treatment process is essentially an
extended aeration or activated sludge process providing
aeration in excess of 24 hours. For economy and simplicity,
an oval-shaped earthen ditch is used for the aeration tank
and air is provided by a horizontally mounted aeration rotor
or brush aerator. The ditch overflow is clarified and the
settled sludge returned to the aeration basin.
A pilot plant using nutrient addition on kraft effluent
(134) demonstrated 68 to 80 percent BOD5 removal at one-day
detention and 80 to 94 percent efficiency at two-day
detention.
Rotating Biological surfaces
Pilot studies have been done on the application of the
rotating biological surface (RBS) concept for biological
treatment of pulp and paper effluents (135). The RBS
process can be described as a dynamic trickling filter.
Plastic discs, supported on a common shaft rotating at from
7 to 17 rpm, serve as a media for biological growth. The
rotating discs are approximately 40 percent submerged in a
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vat having a constant flow of waste water. In pilot tests,
the RBS process has demonstrated its ability to provide high
levels of BOD5 and TSS reduction (301) (302). Biological
solids generated have a low sludge volume and exhibit good
settling characteristics although dewatering properties are
similar to those of activated sludge. The RBS process
recovers quickly from organic and hydraulic overloads, has
no major operational difficulties, and has low maintenance
and manpower requirements. Ninety percent BOD5 removal has
been demonstrated (300) with a BOD5 loading of 1.2 kg/100 sw
m (2.5 lb/1000 sq ft) of disc surface area per day and
detention time greater than 2 hr.
Trickling Filters
The use of trickling filters in all subcategories is very
limited, primarily due to the inability of such systems to
accomplish high degrees of BOD5_ removal at high loading
levels (136). 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 64. 3 kg of
BOD5/CU m of media/day (500 Ib of BOD5/100 cu ft of
media/day) (136) .
Small plastic media filters are sometimes used as pre-
cooling towers and as such also remove some BOD5.
One mill surveyed during this project uses a trickling
filter for treatment of effluent from an integrated
groundwood and kraft pulping and papermaking operation.
This installation suffered from a continual problem of
filter media plugging with fungus growths until a
satisfactory biocide was developed and used.
One pilot study (300) reported up to 72 percent BOD5 removal
at loadings of 1 kg/cu m (62 Ib BOD5/1000 cu ft) per day
but, the efficiency dropped sharply as the loading was
increased. When the loading exceeded 3.2 kg/cu m (200
lb/1000 cu ft) per day the BOD5_ removal was below UO
percent.
Two-Stage Biological Treatment
Two stage biological treatment, consisting of two biological
treatment systems, usually in series can be employed in an
attempt to enhance the BODjS removal obtained with either-
single stage. For example, a trickling filter may precede
an aerated stabilization basin or an activated sludge
system. This arrangement may be employed where the second
stage is required because of insufficient performance of the
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trickling filter alone. It may also be used in cases where
cooling of the waste is desired and in these cases, the
trickling filter serves as a partial cooling tower, and also
accomplishes some BOD£ reduction.
Two stage aerated stabilization basins, operated in series,
have recently been employed in this industry to minimize
adverse temperature effects. Examples include Mills 006 and
007. For the first stage, a detention time of two days or
more is typical, 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 handling surges of flow or pollutant load. Under
conditions of proper design and operation, including
nutrient addition, BODji levels of less than 20 mg/1 can be
expected with these systems.
A two stage biological system currently employed by some
southern bleached kraft mills uses an aerated stabilization
basin followed by storage oxidation. Typically, detention
time of the former is eight to 1U days and for the latter is
eight to 40 days. In these installations, BODji levels of 10
to 25 mg/1 are commonly being achieved. For mills with
adequate land and other favorable factors, this system may
be the most economical approach.
Other combinations of two biological treatment systems are,
of course, possible, but many would not be practical or
economical.
Impact of Temperature Variations
All biological treatment systems are responsive to
temperature particularly to large and/or sudden changes in
water temperature due to climatic influences, spills and the
like. The effect of temperature variations on aerobic
biological systems has been demonstrated in both theory and
practice, and temperature is of importance in the choice of
treatment processes as well as subsequent design and
operation. Pelczar and Reid (137) have stated that all
processes of growth are dependent on chemical reactions, and
the rates of these reactions are influenced by environmental
conditions including temperature. The discussion below
presents theoretical and operational data on temperature
variations and their effects, included is an evaluation of
the effect of temperature on the performance of most of the
biological waste water treatment facilities at mills within
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the subcategory including the resultant variations of both
BOD5_ and TSS removals across such biological systems.
BODS Kinetics
The BOD5 parameter is a measurement of the dissolved oxygen
used by microorganisms for the biochemical oxidation of
organic matter in a waste water. The BOD5 of a waste water
can be broken down into two stages: a first stage in which
the carbonaceous matter is oxidized; and a second stage in
which nitrification occurs. The oxidation of the
carbonaceous or organic matter is directly linked to the
presence of bacteria and other organisms in the waste water.
For a stated set of environmental conditions, growth of
microorganisms will follow a predictable and reproducible
pattern closely allied to the amount BOD5 present in a waste
water and its rate of utilization by the microorganisms
present (310).
The heterogeneoius population of bacteria found in aerobic
biological systems treating waste waters at temperatures
such as those resulting from the production of pulp and
paper encompass three classified groupings of bacteria.
These are the psychophiles, mesophiles, and the thermophilic
organisms.
Seasonal waste water temperature variations encountered in
the biological treatment systems employed by the industry
will primarily change the specific growth rate of the
heterogeneous population and to a lesser extent the relative
distribution of the types of bacteria comprising the
population. McKinney (311) has depicted the rate of growth
for mesophilic organisms with the maximum rate occurring in
the range of 35° to UO°C. Similar growth rate-temperature
distributions exist for both psychrophilic and thermophilic
organisms, optimal growth rate for pyschrophiles occurring
in the range of 10° to 15°C and for thermophiles 60° to
65°C. (312) However, the predominant group found at all
normal operating temperatures in aerobic systems are the
mesophiles, with minor contributions to the total population
coming from the other two groups. (313).
A number of studies have been conducted to quantify various
aspects of microbial growth, temperature, BOD reduction and
the like. Degradation of BOD in pulp and paper wastes has
been evaluated and found to proceed at rates similar to
other waste sources (314) (315) (316) (317) (318) (319)
(320) (321).
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It has been stated that soluble BOD5_ removal by
microorganisms approximates first-order kinetics.
Mathematically, a temperature decrease of 10°C from the
optimal temperature would necessitate an increase in
detention or reaction time of approximately 35 percent to
attain the same effluent BODjj level as that attained at the
optimal temperature. Similarly, an increase in temperature
of 10°C would theoretically shorten the detention time by 25
percent to realize the same soluble effluent BODjj level.
The above concept subsequently is of substantial practical
importance in treatment plant design since flexibility in
design for both microbial and hydraulic detention times
allows treatment systems to sustain efficient operation over
a wide range of conditions, e.g., increased microbial
(sludge) recirculation rates to increase waste/microbe
contact time when microbial activity is reduced in colder
temperatures. Additional studies relate the practical
effects of changes in temperature and BOD and suspended
solids removal to performance for specific systems (322).
Variations in Process Supply, Water Temperature and
Consumption
Water consumption varies between mills in the subcategories,
and factors affecting water consumption, and thus waste
water generation include, among others, process and
processing equipment employed, production rate versus design
capacity of the mill, housekeeping practices, mill upsets,
and required heat balances within the production complex.
A number of mills use surface water supplies as their source
of process waters. Seasonal variations in the temperatures
of these water sources influence water consumption at such
mills. This variable consumption is due mainly to the
maintenance of proper heat balances within the facility.
Data from 25 mills for which adequate data were available
were analyzed and the following variations in consumption as
a function of the season were derived:
Water Usage
Season kl/kkq (k gal/ton)
Winter 114 (27.3)
Yearly Average 120 (28.7)
Summer 172 (30. U)
Winter data were selected on the basis of the coldest 30
consecutive day average biological treatment effluent
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temperature, while summer data were selected on the basis of
the warmest 30 consecutive day average effluent temperature.
As previously discussed, seasonal variations in process
water supply temperatures affect the volume of waste water
generated per kkg (ton) of product produced. Coincident
with the above are variations in raw waste water
temperatures which are also seasonally dependent. Data from
two bleached kraft mills have yielded the following seasonal
temperature variations:
Influent Temperature, °C Data Months
Mill £ Summer Winter Summer Winter
110 40 30 7/73 2/73
119 47 34 8/74 2/75
Heat Transfer
Because the temperature of raw waste waters resulting from
the production of pulp and paper are normally greater than
ambient air temperatures, a transfer of heat from the waste
waters being treated to the atmosphere will occur. Ford, et
al, (323) have stated that heat loss from a mechanically
aerated basin is mainly a function of the differential
temperature between the waste water and air, the aerator
spray cloud, and the surface area and detention time of the
basin. It (324) (325) has been estimated that with low speed
aerators, the heat loss from an aerated basin will
approximate 1400 BTU/HP-Hr.°C difference between the ambient
air and aeration basin temperatures.
Temperature losses across an aeration basin with a detention
time of 10 to 13 days were reviewed and analyzed. Two time
periods were used in the analysis of data from this bleached
kraft mill (Mill f110). Summer data were for the month of
July 1973 and winter data were for the month of February
1973. The results were as follows:
Average Temperature, °C
Season Influent Effluent
»
Summer 40 34
Winter 30 21
As can be seen, summer temperature loss averaged 6°C, while
winter temperature loss approximated 9°C. In addition,
since most aeration basins are designed to approximate
completely mixed reactors, it may be assumed that the
temperature of the contents of the aeration basin approaches
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that of the temperature of the effluent from the basin. In
the above case, summer basin temperature would approximate
34°C, while winter basin temperature would approach 21°C.
Thus, the seasonal variation in basin temperature was 13°C
for the data periods investigated.
Available data on effluent temperatures from secondary
treatment facilities have shown the following average
seasonal variations:
Season Effluent Temperature, °C
Winter 13
Yearly Average 21
Summer 29
These temperatures represent the average 30 consecutive day
minimum and maximum values encountered at each reporting
mill.
Effects on Biological Treatment Systems
Aerobic biological treatment has received wide application
by the pulp and paper industry. Numerous process variations
are currently being used and these various processes employ
different detention times and loading rates, dependent upon
the waste water characteristics and the required degree of
treatment. The following is a summary of the majority of
biological treatment systems and their associated average
design criteria.
Aeration F/M
System Time Organic Loading Ratio
High Purity
Oxygen 1.5-2.0 Hrs. 100-150# BOD/1000 CF 0.7
Rotating Biological
Surfaces 2-3 Hrs. 2-3 Gal/SF/Day 1.0
Activated
Sludge 6-8 Hrs. 50# BOD/1000 CF 0.3-0.5
Extended
Aeration 1-3 Days 15-20* BOD/1000 CF 0.1
Aerated Stabilization
Basin 10 Days 50* BOD/Ac-Ft/Day 0.1
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The above design aeration periods are normally based on a
yearly average daily waste water flow rate. Daily flow rate
variations can alter these established detention times by as
much as 50 percent in the case of activated sludge systems
or as little as 5 percent for aerated stabilization systems.
Temperature reductions through waste treatment systems is
primarily a function of surface area, thus detention time.
As can be seen above, the various biological treatment
systems in use by the industry use varying detention times.
Consequently, the temperature reduction impact will vary for
each system depending on the facility location and the
particular detention time employed.
As noted earlier, temperature reductions in biological
treatment systems will have a twofold effect: (1) decreased
biological activity resulting in increased BOD5 levels in
the effluent and (2) increased solids in the effluent as a
result of incomplete biooxidation and decreased settling
rates. consequently, these phenomena result in a reduction
in the treatment efficiencies unless loading rates,
detention times, or numbers and types of treatment
components are altered to account for this.
While in some industries (e.g., food commodities), changes
are not so apparent, seasonal temperature variations have
been found to have some influence upon the effluent quality
from biological treatment facilities used by pulp and paper
mills in terms of both effluent BOD5 and TSS levels. Data
from the 25 mills indicated the following average changes
over annual average effluent quality values:
Time of Year**
Summer Winter
BOD5* -15% +15%
TSS* + 156 +25%
* Ib/Ton Basis
**Based on warmest and coldest effluent temperatures.
As can be seen from the above, summer operation yielded 15
percent less BOD5_ and a 1 percent increase in TSS in the
final discharge over what was experienced on a yearly basis.
Similarly, winter operations resulted in a 15 percent
increase in BOD5_ and a 25 percent increase in TSS in the
final discharge over what was experienced on a yearly basis.
Comparison of summer to winter values yield an overall
change of 30 percent in BOD5_ and a 21 percent change in TSS.
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It should be noted once again that the above data are
average values and no differentiation has been made between
subcategories, type of secondary treatment system employed,
or geographical location of the facilities.
Of the mills surveyed in this study, 22 with aerated
stabilization basins had temperature data available at their
final discharge. A tabulation of the months in which the
maximum monthly average BODf> at final discharge occurs for
these mills (Table 85) shows that 77 percent had their
maximum BOD!> discharge during the colder months, December to
March, with a remainder randomly distributed throughout the
year.
In an attempt to quantify this apparent low temperature
effect, monthly average final BODf> was plotted against
temperature and a correlation of BOD5 versus temperature was
obtained for 13 ASB's. The ratio of final BODJ5 during cold
months to final BODf> for the warmer months for the 13 was
plotted against detention time in the biological treatment
system as shown in Figure 66.
This figure also includes similar plots for eight hour short
detention biological treatment plants. These eight results
give a scatter of results around 1.0 indicating little
temperature dependence of these treatment systems.
Regarding ASB systems, the data were not sufficient to
warrant any definitive conclusions.
Summary
Temperature changes may have a bearing on the design and
performance of most treatment systems currently used by the
pulp and paper industry. The effects of temperature on
treatment efficiencies are presently being experienced by
mills located in many states. Consequently, in design of
treatment systems located in different locations,
consideration should be given to the impact of temperature
upon variations in effluent quality.
The impact of temperature reductions on treatment
efficiencies will differ for each process considered. On
some systems, the impact will be minimal, where on other
systems it may be pronounced. In such instances, the
consistent attainment of required effluent limitations may
not be achieved unless supplemental treatment is provided.
Ambient air temperature variations will have the greatest
impact on aerated stabilization basin systems. These
systems have the greatest temperature reduction and lowest
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TABLE 85
MONTH OF MAXIMUM AVERAGE BOD AT FINAL DISCHARGE
FOR SURVEYED MILLS WITH ASB (73-74 SURVEY DATA)
Month of Temp of Discharge
Max BOD at for Month of
Mill Code Final Discharge Max BODS °C
001 February 20.2
005 November 18.1
006 February 16.5
007 February 17.6
051 April 17.8
052 November . 19.6
100 February 16.3
101 February 4.4
106 March 14.2
109 June 36.0
110 February 10.4
113 February 15.2
114 May 25.1
116 March 27.7
117 January 14.6
121 December 17.0
125 February 13.6
203 January 10.5
204 September 27.6
205 December 5.8
263 March 13.1
359 January 5.6
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3.0
CO
CO
o
CD
m
2.0
CO
^3-
ro
DAY 2 DAYS
4 DAYS 6 DAYS 8 DAYS 10 DAYS 12 DAYS 14 DAYS
DETENTION TIME THROUGH TREATMENT SYSTEM
16 DAYS
18 DAYS
FIGURE 66
EFFECT OF TEMPERATURE ON BIOLOGICAL TREATMENT SYSTEMS
-------
operating temperature because of their long detention
periods. The rate of biological activity will be altered
because of the above. In addition, ASB systems do not use a
formal solids capture or settling process following
aeration. Quite often only a quiescent zone is provided for
this unit operation, and such zones generally yield less
than optimal solids liquid separation, even under ideal
conditions.
The extended aeration system also will be affected; however,
the impact will not be particularly severe. The detention
time (1-3 days) will permit variations in operating
temperatures. However, in general this variation will not
be as significant as in ASB systems. The solids are
captured in a clarification process, consequently, the
increase in effluent solids should be less than that of an
ASB system. This system, in general, should be capable of
consistently meeting effluent limitations even in the most
rigorous climate areas.
Variations in removal efficiencies as a result of ambient
air temperature fluctuations for high rate systems should be
negligible. These systems either have extremely short
detention times, i.e., small temperature decreases, or the
processes are enclosed.
Therefore, designs and operations of treatment systems
should take into account the impacts of temperature upon
biological treatment effectiveness.
Sludge Handling and Disposal
The disposal of sludges obtained from the clarification of
pulp and papermaking effluents is still a major problem
despite many years of research development work, field
studies, and applications. 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 sludge cake was excavated and dumped on waste land
and the basin was returned to service. Odor problems from
drying unthickened sludge as well as land limitations have
now demanded the adoption of more advanced practices (64).
These practices include mechanical dewatering, improved
landfilling techniques as described in Section VTII, and
incineration.
In practically all systems, the dewatering operation
operation is more efficient and economic when the feed
sludge solids content is high. Hence, it is desirable, even
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if not necessary, to prethicken sludge. This may be
accomplished by providing a high level of sludge storage
capacity within the mechanical clarifier or by gravity
thickeners of the "picket-fence11 type. Small mills
sometimes employ high conical tanks which contain no
mechanism but have wall slopes in excess of 60° and which
act as both storage tanks and thickeners.
If the proportion of excess secondary solids to primary
solids is high as in the activated sludge system, it may be
necessary to utilize dissolved air flotation to prethicken
the secondary sludge prior to blending it with the primary
sludge for final dewatering.
Vacuum filters are in common use for dewatering sludges from
pulping and papermaking and produce cakes ranging from 20 to
30 percent solids. The filtration rates vary greatly
depending on the nature of the sludge.
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
$3.30 to $5.50 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.
A number of different types of filters are in service, with
the continuous rotary vacuum filter, similar to the drum
filter used in pulp washing being widely used. Among recent
installations coil or belt types are the most popular.
Centrifuges have proven successful in dewatering pulp and
paper mill sludges and generally produce cakes with moisture
contents similar to those generated by vacuum filters.
The application of drying beds for dewatering sludges is
limited to small mills and they are not constructed as
elaborately as are those employed for sanitary sewage. They
generally consist only of multiple beds of gravel or cinders
without a complex underdrain system.
Additional water cen be removed from vacuum filter and
centrifuge sludge cakes by pressing; cakes approaching 50
percent solids can be obtained.
Recent efforts have been toward direct use of presses on
thickened sludge, thus eliminating the first dewatering step
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Pressing is normally employed when incineration is
to be used for disposal since it reduces or eliminates the
need for supplementary fuel to maintain combustion.
Pressing may become more common as a process preceding
landfill, however, as an aid in preventing groundwater
contamination from leachate. This is elaborated upon in
Section VIII.
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. Several factors have made
such practices generally undesirable, however. Odors form
upon decomposition of these materials, there is a potential
for pollution of nearby surface waters, and affected lands
are eliminated from potential future uses. If proper
techniques are applied as described in Section VIII,
however, landfilling of sludges from the pulp and paper
industry should continue to be a viable alternative for
ultimate sludge disposal.
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 (144) experimented with the use of this material
as an organic soil supplement and with hydromulching. The
incorporation of high sludge levels into soil, after
permitting it to stand 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 successive year caused a reduction in crop yields
which was apparently due to nitrogen unavailability. In the
hydromulching tests when 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. Primary sludge is being applied to the land at
loads (dry solids) of 224-448 kkg/ha (100-200 tons/ac).
Cottonwoods are planted with planned harvest and
reapplication of sludge in three to five years.
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 fusca, strongly
cellulolytic thermophylic organism on low lignin pulp mill
fines (145). This process is attractive in that acid
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hydrolysis of the cellulose prior to fermentation is not
required. The substantial reduction of organic matter
attained is of considerable interest. Preliminary tests
show that the thermo-monospora fusca is palatable and
nontoxic as animal feed and could be competitive in cost
with other protein sources.
The recycling of primary clarifier sludge from the
manufacture of uncoated and/or unfilled papers is
successfully being used in several sufccategories, mainly in
unbleached coarse pulp production. In addition, a limited
number of nonintegrated paper mills have successfully
recycled the sludge back into the broke system. It appears
possible that any non-integrated paper mill producing
unpigmented papers could recycle part or all of their
primary sludge back into the paper making process. Primary
sludge from a mill producing pigmented papers has been
recycled to reclaim the reuseable fillers by incineration.
Although the process was successful, the cost of the
recovered filler was higher than delivered virgin filler
rendering the system economically unjustified for the time
being.
The following is a description of a primary sludge recycling
system from one non-integrated paper mill producing 227 kkg
(250 tons) /day of fine uncoated papers, white and colored.
The mill operates on purchased bleached kraft pulp.
The primary clarifier receives approximately 15 MLD (4 MGD)
from the fine paper mill with all influent passing over a
Cowan screen prior to entering the clarifier. All of the
sludge (23 to 27 kkg (25 to 30 tons)/day) is recycled.
Sludge is pumped at 10 to 14% from the primary clarifier to
a sludge storage tank in the mill's bleach plant. From
storage the sludge is pumped to the suction of the
unbleached broke storage tank pump. The sludge is then
blended with a stream of unbleached broke (36 kkg (40
tons)/day) by a manually operated valve. The combined stock
is then pumped to a belt thickener and on to a single bleach
tower. All cleaning of the pulp, including the sludge, is
in the primary and secondary centricleaners located in the
bleach plant. This mill reports good clean pulp and no
problems in the production of their papers with the use of
sludge in the process.
Pulp and paper mill sludge can be incinerated in either
combination (bark/fossil fuel/sludge) toilers or in waste
water sludge incinerators of the multiple hearth or
fluidized bed type.
352
-------
The principles of sludge burning are essentially the same
for all of the types of incineration equipment that are
currently in use for conventional sludge burning (1). The
efficient incineration of any material requires:
1. Time - The time necessary for combustion to take place
2. Temperature - The heat necessary to accomplish combustion
3. Turbulence - The agitation necessary to mix the waste and
expose new surfaces to the heat.
Incineration of sludges involves two basic steps:
1. A drying step where the heat of combustion is
utilized to evaporate moisture from partially dewatered
sludge prior to charging it to the combustion zone.
2. A combustion step where the sludge is burned. In
this step, carbon, nitrogen, hydrogen, sulfur and other
elements present are oxidized in the presence of excess
air.
With the multiple hearth incinerator, sludge enters the top
of the cylindrical unit and is dropped onto the top hearth.
Rotating "rabble" arms rake the sludge across the hearth,
first toward the center of the hearth, where it then drops
downward onto the next hearth. Here the rabble arms rake
the sludge back across the hearth toward the periphery where
it then drops downward to the next hearth, and repeats the
cycle.
As the material passes down through the furnace, four
mechanisms of sludge burning take place; first, the drying
process takes place, in the upper hearths, as moisture is
driven off by rising hot combustion gases; second, the
volatile solids in the sludge are burned; third, the fixed
carbon in the solids are burned; fourth, the red hot ash
cools. In the last hearth, the ash is raked out of the
incinerator and removed for disposal.
With a fluidized bed incinerator a mass of inert particles,
usually silica sand, is retained in suspension by an upward-
moving stream of hot air within a reactor vessel. In this
state, the particles exhibit the properties of a fluid, thus
the name fluidized bed incineration. Air for the fluidizing
medium is supplied by air blowers. The sludge is then fed
into the unit where it mixes with the fluidized sand bed due
to the boiling action of the bed itself. Water in the
sludge is evaporated and the combustible solids are
oxidized.
353
-------
With either of these incinerator systems, auxiliary fuel
must be burned to achieve the necessary heat to assist in
combustion, if the sludge is not autocombustible (i.e., if
the heat value of the sludge is not high enough to generate
the heat necessary to evaporate the water present in the
sludge). Steam, plus the gaseous products of combustion of
the organics and auxiliary fuel, plus the fine inert ash
solids suspended in waste stream, exit from the top of the
reactor. The exhaust gases are normally cleaned in a
venturi scrubber and cooled in a multi-tray cooling tower.
The ash drops to the bottom of the tower and the ash slurry
is removed for disposal.
Irrigation and Land Disposal of Effluents
Total effluents of some non-integrated paper mills, have
been disposed of by means of irrigation and land disposal.
Specific effluents from pulp mills such as cooking liquors,
foul condensates, and turpentine decanter water, have also
been treated in this manner.
The advantage of land disposal, when properly practiced, is
that a very high degree of purification occurs as the water
passes through the soil. Approximately 20 percent or more
of the waste is evaporated by this process. When the
remaining waste finally reaches either the adjacent stream
or ground water, it is practically devoid of suspended
matter, BODji, and color. The disadvantages are 1) the
relatively small volume that can be disposed of per acre per
day, 37,850 to 113,550 1 (10,000 to 30,000 gal) under most
soil conditions, and 2) freezing problems during the winter
months. 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
354
-------
U. Controlled effluent application designed to produce
crops by use of suitable irrigation practices.
Since these effluents contain little in the way of 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 irrigation for
disposing of these wastes has been described in detail in
the literature (1U6). An assessment of the effectiveness of
irrigation on crop growth and the parameters for application
of water, BODI5, cellulose, and sodium for soils of different
character and textures are set forth.
Foam Control
Effluent foaming in receiving waters is a problem
experienced particularly by kraft and soda pulp mills since
alkaline liquors have a strong propensity to impart this
quality to water. Other waste constituents can do likewise
but these are the most common offenders in both treatment
plants and receiving streams. Some paper mill wastes can
also cause this effect due to residual amounts of additives
present in the white water discharged, as can coating
kitchen wash waters.
There is relatively little literature on the measurement of
foaming capacity or its control in pulp and paper effluents
despite the fact that control methods are well established,
widely used, and quite effective. A method has been
developed (126) for comparing foaming potential based upon
methods employed in the detergent industry which appears to
be the only technique presently available to measure this
factor in pulp and paper effluents.
Foaming problems are common within kraft and soda mills
themselves and these difficulties are frequently the cause
of the problem in effluents, foais or black liquor being
carried directly into sewers. In-mill sewering arrangements
can also give rise to foaming. This can be avoided by
rearranging the sewer system to prevent direct admixture of
alkaline and acid waste waters within them and correcting
arrangements and pumping systems which give rise to air
entrapment, a major cause of foaming in itself. Maximum
control of black liquor losses is mandatory if foaming is to
be kept at a reasonable level both during effluent treatment
and in discharge.
Since some biological treatment processes depend upon
aeration of the waste, foam is bound to develop. Under
355
-------
normal conditions with most wastes this can be maintained at
a minimum level by in-plant control or by the use of surface
sprays installed in treatment basins. In most instances
with good mill loss control, foam levels will stabilize in
treatment units and not become unmanageable. Biological
treatment is effective in itself in reducing foaming
tendencies.
Treatment Systems for Removal of Zinc
The removal of zinc from waste waters by groundwood mills
using zinc hydrosulfite as a bleaching agent can be achieved
through either (1) chemical coagulation and clarification or
by (2) changing to another chemical bleaching agent such as
sodium hydrosulfite. Several alternative chemical
coagulation and clarification technologies and their
application to industrial and municipal waste waters are
discussed below.
In the zinc segment of the nonferrous metals manufacturing
industry, treatment for removal of zinc levels ranging from
5 to 243 mg/1 includes a lime application and settling
process. The treatment consists of adding a milk of lime
slurry to the waste water to precipitate the hydroxide of
the heavy metals and reduce dissolved sulfate concentrations
through the formation of gypsum. Sufficient lime is needed
to adjust the pH to between 10 and 11.5. Also, settling may
have to be aided by adding small quantities of organic
polyelectrolytes.
In the copper, nickel, chromium, and zinc segment of the
electroplating industry, treatment for removal of typical
zinc concentrations of 32 mg/1 consisted of neutralization,
neutralization and precipitation, and clarification. This
system of treatment was reported to be capable of
effectively treating effluents from plants of any size and
reducing metal ion concentrations in the effluent to 0.5
mg/1 or less. A holding tank prior to treatment was
recommended for manufacturers who experience wide ranges in
pH. A pH of 8.8 was recommended in the neutralization and
precipitation portion of the treatment system.
Zinc hydroxide formed by the neutralization portion of the
treatment is a gel-like floe which settles very slowly.
Metal ions such as ferric ions should be added to the waste
water as a coagulating aid, and a polyelectrolyte could be
added after the ferric ion to further improve settling of
the zinc hydroxide floe. Further removals can be
accomplished by use of polishing filters or sand filters
after clarification. Levels of 0.3 mg/1 zinc are reported
356
-------
to be commonly achieved with this technology beginning with
about 32 mg/1.
Removal of zinc to the 0.1 to 1.0 mg/1 range at a municipal
treatment plant receiving pretreated industrial waste with
concentrations of 2 to U mg/1 in the raw waste influent was
discussed by Daniels (346). Zinc was one of five metals
present in the waste water. A three-stage removal system
for these heavy metals was discussed. It consists of a pH
adjustment stage, sedimentation augmented by chemical
coagulation/flocculation, and additional removal by
filtration if levels of zinc below 1 mg/1 are required.
The chemicals involved in each of the portions of the
treatment may be caustic, lime, or soda ash for pH
adjustment (pH in the 7.5 to 9.0 range are used), ferrous or
ferric chloride, aluminum sulfate, or lime for coagulating
and a synthetic organic polyelectrolyte for flocculating.
The method of chemical application at the municipal plant
was to utilize existing portions of the treatment system to
accomplish mixing and settling of the metal hydroxides
formed. Ferric chloride was added in a flume prior to the
grit chamber at a dosage of 18.3 mg/1 and an anionic
polymer, Purifloc A23, was added at the grit chamber. The
raw influent zinc concentration over a 280-day test period
averaged 2.8 mg/1 with the primary clarifier effluent being
1.2 mg/1 and the final effluent averaged 0.9 mg/1. This
resulted in an average removal efficiency of 68 percent.
Daniels pointed out that the removal efficiency for
insolubilized metals in existing plants will be governed
principally by the hydraulic conditions in the clarification
process.
It should be noted that zinc removal was not the primary
purpose involved in this treatment method and through
optimization of chemical application points, concentrations,
and pH levels best suited for forming zinc hydroxide in the
waste water, better removal efficiencies could be expected.
Zinc removal at a viscose rayon manufacturing plant was
discussed in another report (3U7) . One object of the work
done at this waste water plant was to perfect the operation
by which excess acid was neutralized and the soluble zinc
was precipitated and removed.
Caustic soda was added up to 285 mg/1 of soluble zinc
sulfate until a pH of 9.5 was reached and most of the zinc
357
-------
was precipitated. A coagulant aid was used in the clarifier
at an approximate rate of 0.4 mg/1 to promote settling.
A nonferrous metal and alloy fabricating plant in England
reported on their experience with developing a treatment
system for the removal of heavy metals in their waste water
below a maximum total value of 1 mg/1 (348). The metals
found in the waste water were copper, chromium, zinc nickel,
and iron. The method of treatment required to remove these
metals to a total concentration below 1 mg/1 was
neturalization, clarification and filtration.
A three-stage pH adjustment structure, using a lime slurry
application, with mixing, is used to achieve a pH of 8.7+^
0.1 with an influent range to the structure of 1 to 7. The
zinc effluent concentrations resulting from this treatment
were from 0.23 to 2.30 mg/1. Filtration with six pressure
sand filters were then added after clarification to meet the
discharge requirement. Zinc effluent concentrations
resulting from the filtration ranged between 0.07 and 0.50
mg/1.
External Treatment and Effluent Characteristics at Surveyed
Mills
Table 86 summarizes the approximate use of
technologies by mills within the sufccategories
this report. Figure 67 presents schematic
containing information and data on the external
facilities at most surveyed mills with biological
facilities. The treatment facilities and the
effluent characteristics for surveyed mills are
below.
Bleached Kraft Mills
external
covered in
drawings
treatment
treatment
resulting
discussed
Extensive effluent data were available for 32 bleached kraft
mills that have biological treatment facilities. The
influent BOD5_ and effluent flow, BOD5, and TSS
characteristics are presented in Table 87 along with the
type of treatment facility at each mill. Aerated
stabilization basins (ASB) or activated sludge systems (A)
are used by most surveyed mills and many mills follow the
ASB or A with either post storage ponds (PS) or clarifiers
(C). In addition, one mill, mill 132, uses a natural
aeration basin (NAB) without mechanical aeration for its
biological treatment system.
The data presented in Table 87 represents in most cases from
12 to 24 months of daily data. Several mills use non-
358
-------
TABLE 86
EXTERNAL TECHNOLOGIES CURRENTLY IN USE (1973)
Data are approximate percentages of use in each subcategory.
SUBCATEGORY
GROUNDWOOD
BLEACHED
KRAFT
SULFITE
DISSOLVING
SULFITE
SODA
DE INKED
TISSUE
FINE
PRIMARY
CLARIFICATION
60
60
50
100
65
40
40
30
BIOLOGICAL
A*
10
10
5
5
5
TREATMENT
ASB**
20
40
10
33
35
15
5
5
POST
STORAGE
35
50
25
20
35
25
* Activated Sludge
** Aerated Stabilization Basin
359
-------
O)
Cl
O
Figure 67
EXTERNAL TREATMENT FACILITIES
Bleached Kraft Segment
Mill Code
100
C-ASB-PS
101
C-ASB-PS
102
C-ASB-PS
Bleach Plant
Air Injection
4 days
11.85 Hp
7 days
Bleach Plant Strong Liquor
20 days
850 Hp
15 days
02 Injection
Existing Creek Flow
4 days
750 Hp
9.5 days
Woodyard
Bleach Plant
-------
Figure 67 - (cont'd)
Go
en
EXTERNAL TREATMENT FACILITIES
Bleached Kraft Segment
Mill Code
103
C-ASB-PS
104
C-A
105
C-ASB-PS
Bleach Plant
Bleach Plant
Caustic Ext. Bleach Plant Acid Sewer
-------
OJ
GI
ro
Figure 67 - (cont'd)
EXTERNAL TREATMENT FACILITIES
Bleached Kraft Segment
Mill Code
106
C-ASB-PS
107
C-A-ASB
108
C-A
Bleach Plant
10 days
400 Hp
Paper Mill
•*• \ 5 hours
Sludge Return
Mill
/ Holding \
\ Pond /
58 days
Spray Irrigation
Bleach Plant
I
Nutrient
-------
Figure 67 - (cont'd)
EXTERNAL TREATMENT FACILITIES
Bleached Kraft Segment
Mill Code
109
C-ASB
6 days
1500 Hp
Nutrients
110
C ASB-C
Nutrients
111
C-ASB
8 days
1650 Hp
-------
OJ
0.
Mill Code
112
C ASB-C
113
C ASB
114
C-ASB-PS
Figure67 - (cont'd)
EXTERNAL TREATMENT FACILITIES
Bleached Kraft Segment
3.75 days
600 Hp
4 Return Sludge
Nutrients
15 days
1990 Hp.
-------
Figure 67 - (cont'd)
EXTERNAL TREATMENT FACILITIES
Bleached Kraft Segment
CJ
CTl
cn
Mill Code
116
C-ASB
117
C-ASB
118
C-A
By-Pass
1.25 days
75b Hp
Nutrients
14 days
480 Hp
4.6 hours
0.75 days
420 Hp
4 hours
-------
OJ
a-.
Figure 67 _ (cont'd)
EXTERNAL TREATMENT FACILITIES
Bleached Kraft Segment
Mill Code
119
C-A
120
C-A
121
C-ASB-PS
Nutrients
( 761 gpd/ft2 I'
7 hours
Sludge Return
Return Sludge
Nutrient
7 days
-------
Figure 67 - (cont'd)
EXTERNAL TREATMENT FACILITIES
Bleached Kraft Segment
Mill Code
122
C-ASB-PS
12 days
900 Hp
197 days
125
C-ASBPS
127
C-ASB
8.5 days
1920 Hp
-------
Mill Code
130
C-ASB
CO
Ctt
00
136
C-A
Figure 67 - (cont'd)
EXTERNAL TREATMENT FACILITIES
Bleached Kraft Segment
6.6 hours
2500 Hp
-------
Figure 67 ~ (cont'd)
EXTERNAL TREATMENT FACILITIES
Bleached Kraft Segment
Mill Code
131
C-ASB
6.5 days
1250 Hp
-------
Figure 67 - (cont'd)
EXTERNAL TREATMENT FACILITIES
Soda Segment
Mill Code
152
C-ASB
00
--J
o
150
C-TF-C
Trickling Filter
2091 gpd/ft2
-------
GO
--J
Mill Code
001
C-ASB-PS
002
C-A
003
C-TF-C
Figure 67 - (cont'd)
EXTERNAL TREATMENT FACILITIES
GroundwoodSegment
Nutrients
12 hours
240 Hp
Sludge Return I
Nutrients
Wet Well
Trickling
I Filter J ^ |697gpd/ft'
Sludge Return
-------
Figure 57- (cont'd)
EXTERNAL TREATMENT FACILITIES
Groundwood Segment
Code
005
C-ASB
-------
CJ
-^1
t J
Figure 67 - (cont'd)
EXTERNAL TREATMENT FACILITIES
Sulfite Segment
Mill Code
51
C-ASB
52
C-ASB
53
C-A
Weak Wash, Yeast Plant, Recovery, & Bleach Plant
Nutrients
7 hours
10 days
375 Hp
Pulp
Mill
Nutrients
Paper Making
Return Sludge
-------
Figure 67 - (cont'd)
EXTERNAL TREATMENT FACILITIES
Sulfite Segment
Mill Code
006
CASE
Nutrients
12.6 days
1200 Hp
Nutrients
007
C-ASB
6 days
1100 Hp
Nutrients
401
ASB-PS
7-8 days
3200 Hp
Sludge Retain
-------
CO
*-J
en
Mill Code
203
C-ASB
204
C-ASB
205
C-ASB
Figure 67 - (cont'd)
EXTERNAL TREATMENT FACILITIES
DEINK Segment
Nutrients
1.4 days
180 Hp
6 days
180 Hp
-------
Figure 67 - (cont'd)
EXTERNAL TREATMENT FACILITIES
DEINK Segment
Mill Code
206
C-ASB-C
By-Pass
5 days
k \ /
1400 Hp
Sludge Return
5.3 hours
216
C-A
Return Sludge
-------
Figure 67 - (cont'd)
EXTERNAL TREATMENT FACILITIES
Fine Segment
Mill Code
250
C-ASB
251
ASB
20 Hp
45 days
10 Hp
45 days
257
C-ASB-C
-------
Figure 67 - (cont'd)
EXTERNAL TREATMENT FACILITIES
Fine Segment
Mill Code
263
C-ASB
CO
^1
00
-------
TABLE 87
BLEACHED KRAFT MILLS
FINAL EFFLUENT CHARACTERISTICS
CO
—I
Final
Effluent Flow
Mill
127
108
114
130
140
105
109
111
121
117
113
122
100
138
131
116
118
134
119
132
112
136
103
106
101
107
110
120
104
125
501
166
Raw
Waste
BODS
kl/kkcL(kqal/ton) mgA
233.0
231.0
179.0
256.0
80.5
162.0
167.0
142.0
158.0
204.0
141.0
123.0
155.0
133.0
159.0
140.0
125.0
93.0
97.2
81.3
110.0
120.0
171.0
171.0
159.0
187.0
100.0
130.0
219.0
108.0
199.0
126.0
(55.9)
(55.4)
(42.9)
(61.5)
(19.3)
(38.9)
(40.0)
(34.1)
(37.9)
(49.0)
(33.7)
(29.5)
(37.2)
(32.0)
(38.1)
(33.5)
(30.0)
(22.3)
(23.3)
(19.5)
(26.4)
(28.7)
(40.9)
(40.9)
(38.2)
(44.8)
(24.0)
(31.2)
(52.5)
(25.9)
(47.7)
(30.2)
153
295
276
120
350
224
213
213
189
146
260
367
293
375
-
356
189
332
240
289
224
242
232
204
182
264
277
369
183
288
-
237
Final Effluent
BODS
Treatment
C-ASB
C-ASB
C-ASB
SB-ASB
SB-ASB
C-ASB-PS
C-ASB
C-ASB
C-ASB-PS
C-ASB
C-ASB
C-ASB-PS
C-ASB-PS
C-ASB
C-ASB
C-ASB
C-A
C-ASB-C
C-A
SB-NAB
C-ASB-C
C-A
C-ASB-PS
C-ASB-PS
C-ASB-PS
C-A-PS
C-ASB-C
C-A
C-A
C-ASB
C-ASB
C-ASB
kg/kkg
5.4
8.5
4.6
2.9
7.2
2.6
6.2
3.2
4.4
2.8
4.8
11.7
11.5
4.4
6.9
8.8
8.2
7.6
1.1
6.8
1.5
3.8
2.3
3.1
1.5
3.3
3.4
3.6
7.3
3.2
11.9
3.1
(Ibs/ton)
(10.7)
(16.9)
( 9.2)
( 5.8)
(14.4)
( 5.1)
(12.4)
( 6.3)
( 8.7)
( 5.5)
( 9.6)
(23.3)
(22.9)
( 8.8)
(13.7)
(17.6)
(16.3)
(15.1)
( 2.2)
(13.5)
( 2.9)
( 7.6)
( 4.6)
( 6.2)
( 2.9)
( 6.6)
( 6.8)
( 7.1)
(14.6)
( 6.3)
(23.8)
( 6.2)
mgA
23
37
26
11
90
16
37
22
28
13
34
95
74
33
43
63
65
81
11
83
13
32
31
18
9
18
34
27
33
29
60
27
TSS
kg/kkg
8.6
11.1
3.8
6.5
7.3
-
17.0
6.5
5.7
4.8
-
13.6
5.8
9.1
-
39.4
13.5
24.2
3.3
5.0
15.4
29.9
1.6
3.5
2.1
12.1
7.0
13.8
13.6
6.1
15.9
5.4
(Ibs/ton)
(17.1)
(22.2)
( 7-. 5)
(13.0)
(14.5)
( - )
(34.0)
(13.0)
(11.3)
( 9.6)
( - )
(27.2)
(11.5)
(18.1)
( - )
(78.7)
(26.9)
(48.3)
( 6.5)
( 8.9)
(30.7)N
(59.8)
( 3.2)
( 6.9)
( 4.2)
(24.1)
(13.9)
(27.6)
(27.2)
(12.1)
(31.7)
(10.8)
mgA
37
48
21
25
90
-
102
46
36
23
-
Ill
37
68
-
282
107
260
33
55
139
250
21
20
13
64
69
106
62
56
80
46
Subcategory
Diss.
Diss.
MKT
MKT
MKT
BCT
BCT
BCT
BCT
BCT
BCT-MKT
BCT-MKT
BCT-MKT
BCT-MKT
BCT-MKT
Fine
Fine
Fine
Fine
Fine
Fine
Fine
Fine-MKT
Fine-MKT
Fine-MKT
Fine-MKT
Fine-MKT
Fine-MKT
Fine-BCT
BCT-MKT
BCT-MKT
Fine-BCT
N Non-standard methods TSS analytical measurement technique.
-------
standard analytical techniques for TSS measurement and data
for those mills are qualified in the table by the letter
"N". The TSSN data is presented only for information
purposes and was not used in any data analyses.
The final effluent BODS concentrations from the 32 bleached
kraft mills in Table 87 are arrayed in order of increasing
concentrations in Table 88. The table also presents the
type of biological treatment system, the influent BOD5_
concentration, and the effluent TSS concentration. Figure
68 presents a graphic display of the BOD5_ and TSS data
presented in Table 88. The BOD5_ is plotted as the primary
parameter with the attendant TSS concentrations. Figure 68
shows an obvious break point between 38 mg/1 and 43 mg/1
above which the slopes increase sharply. The average BOD5_
concentration for the 24 mills achieving BOD5_ concentration
up to 43 mg/1 is 25 mg/1 while the average BOD5_ for all 32
mills is 38 mg/1. The average TSS concentrations for the
best 24 mills excluding mills using non-standard analytical
methods and (excluding mill 136 which has deficiencies in
the design of the secondary clarifiers resulting in very
high TSS concentrations) is 47 mg/1 and for all of the mills
in the table is 71 mg/1. While only final effluent
concentrations are plotted in Figure 68 and not
corresponding influent concentrations, the "break-point" in
final effluent BOD5_ qualities represents a break in control
technologies in use by the bleached kraft mills for which
data were available. Those below 38 to 43 mg/1 are more
representative of BPCTCA than those with effluents qualities
above 43 mg/1. The primary impact on the effluent qualities
from the bleached kraft mills is the design and operation of
the treatment systems. While influent BOD5_ concentrations
do have some impact on effluent BOD5_ and TSS concentrations
(assuming adequate primary treatment for removal of raw
waste TSS), Figure 69 is presented to illustrate that low
levels of BOD5_ are being achieved by bleached kraft mills
with BOD5_ influent concentrations ranging from 120 mg/1 to
375 mg/1.
Examination of the treatment technologies in use at the
mills included in Figure 69 shows that the higher BOD5_ and
TSS concentrations being achieved are apparently due to
treatment system design deficiencies. In addition, several
of the best 24 mills are discharging high concentrations of
TSS while achieving low concentrations of BOD_5 (i.e. mills
136, 109, and 120). This indicates that the treatment
system design was deficient for its control of TSS. For
example, mill 109 is achieving 37 mg/1 BOD5_ but discharging
an average of 102 mg/1 TSS. As shown in Figure 67, the
treatment system at mill 109 has an ASB with 1500 hp which
380
-------
TABLE 88
BLEACHED KRAFT MILLS
BIOLOGICAL TREATMENT: EFFLUENT CHARACTERISTICS (mg/L)
Mill
101
130
119
117
112
105
106
107
111
127
114
166
120
121
125
103
136
104
138
110
113
109
108
131
501
116
118
100
134
132
140
122
Subcategory
Fine-Mkt
Mkt
Fine
BCT
Fine
BCT
Fine-Mkt
Fine-Mkt
BCT
DISS
Mkt
Fine-BCT
Fine-Mkt
BCT
BCT-Mkt
Fine-Mkt
Fine
Fine-BCT
BCT-Mkt
Fine-Mkt
BCT-Mkt
BCT
Diss
BCT-Mkt
BCT-Mkt
Fine
Fine
BCT-Mkt
Fine
Fine
Mkt
BCMflct
Treatment
C-A5B-PS
SB-ASB
C-A
C-ASB
C-ASB-C
C-ASB-PS
C-ASB-PS
C-A-PS
C-ASB
C-ASB
C-ASB
C-ASB
C-A
C-ASB-PS
C-ASB
C-ASB-PS
C-A
C-A
C-ASB
C-ASB-C
C-ASB
C-ASB
C-ASB
C-ASB
C-ASB
C-ASB
C-A
C-ASB-PS
C-ASB-C
SB-NAB
SB-ASB
C-ASB-PS
Raw
Waste
BODS
182
120
240
146
224
224
204
264
213
153
276
237
369
189
288
232
242
183
375
277
260
213
295
-
-
426
189
293
332
289
350
367
Final Effluent
BODS TSS
9
11
11
13
13
16
18
18
22
23
26
27
27
28
29
31
32
33
33
34
34
37
37
43
60
63
65
74
81
83
90
95
13
25
33
23
139N
-
20
64
46
37
21
46
106
36
56
21
250
62
68
69
-
102
48
-
80
282
107
37
260
55
90
111
N Non-standard methods TSS analytical measurement technique
381
-------
140
1
120-
100.
§
I
00 -P
oo ti
80_
40J
Figure 68
Bleadhed Kraft Mills
Biological Treatment: Effluent Characteristics
o
O TSS
A BOD5
ND (No Data)
N (Won Standard
methods)
i Off the Scale
O
A A
A A
ND
A A
ND
ND
1 1 i 1 \ 1 i T
(n/N+l)x 100
1 - 1
Note: Each Point
represents the final
effluent concentration
from a single bleached
kraft mills
biological treatment
system.
II III I I I
-------
420
380
340
300
260
O
CO
C
Ol
4-
•5 2201
18C
14C
Figure 69
Bleached Kraft Mills
Biological Treatment: Influent vs. Effluent (BOD5)
IOC
20
60 I
Effluent BODS (mg/1)
383
100
-------
is adequate for BOD5_ removal but has only six days of
detention time. The adequate aeration capacity and the six
days of detention time allow adequate oxidation of the
soluble BOD5_, but the biological organisms are apparently
still in the log or declining growth phases rather than in
the endogeneous respiration growth phase. Adequate designs
of aerated stabilization basins include detention times into
the endogeneous respiration growth phase. Detention times
for ASB's of eight to 14 days are normally considered
adequate to achieve low levels of both BOD5_ and TSS in the
final effluents. Thus, adequate aeration capacity and
detention times are both a necessity in achieving low levels
of both BOD5 and TSS in the final effluent from biological
treatment systems.
For mills using activated sludge treatment systems, proper
design of the secondary clarifiers is one of the cirtical
parameters necessary to achieve low concentrations of TSS.
Mill 136, for example, is achieving BOD5 concentrations in
the final effluent of 32 mg/1 but discharging 250 mg/1 TSS.
The secondary clarifier overflow rates at mill 136 are
considerably higher than 20,371 Ipd/sq.m (500 gpd/ft.2) to
24, HH5 Ipd/sq.m (600 gpd/sq.ft) which are normally
considered as adequate overflow rates for secondary
clarifiers. The mill is presently planning to modify the
secondary clarifiers and reduce the overflow rates. In
addition to reducing the TSS levels in the final effluent,
the BOD5_ levels will probably also be reduced due to more
effective treatment and solids capture. Another example of
the impact of inadequate design on the final effluent
qualities is mill 101. As shown in Figure 67, mill 104 uses
an activated sludge treatment system to achieve average BOD5_
and TSS concentrations of 33 mg/1 and 62 mg/1, respectively.
The overflow rates of the primary and secondary clarifiers
at mill 104 are 32,593 Ipd/sq.m (800 gpd/sq.ft.) and 48,890
Ipd/sq.m. (1200 gpd/sq.ft.), respectively, both of which are
well above the normally accepted design overflow rates of
20,371 Ipd/sq.m. (500 gpd/sq.ft.) to 24,445 Ipd/sq.m (600
gpd/sq.ft.). A recent study by mill 104 indicated that
modification of the secondary clarifiers to an overflow rate
of 28,519 Ipd/sq.m. (700 gpd/sq.ft.) would result in
significantly reduced TSS concentrations in the final
effluent. It should be pointed out that inadequate primary
treatment can have detrimental impacts on final effluent
qualities and modifications to the primary treatment may be
necessary in addition to modifications to the secondary
clarifiers.
In summary, the information and data presented in Table 88
and Figures 67, 68 and 69 show that influent BOD5_
384
-------
concentrations can have some impact, but the design and
operation of the treatment facilities at the bleached kraft
mills for which data were available is the primary impact on
final effluent qualities. For example, mills 138 and 120
have influent BOD!? concentrations of 375 mg/1 and 369 mg/1,
respectively, and achieve effluent BOD5 concentrations of 33
mg/1 and 27 mg/1, respectively. Only one of the 32 mills in
Table 88 has a higher influent BOD5 and that mill is mill
116 with 426 mg/1. As shown in Figure 67, mill 116 uses an
ASB to achieve effluent BOD5 and TSS concentrations of 63
mg/1 and 282 mg/1, respectively. The ASB has only two days
of detention which is inadequate for EOD5 and TSS reduction.
Thus, the break-point in the curve in Figure 68 represents a
change in technology as examination of the treatment systems
at the mills achieving BOD5 concentrations above 43 ing/1
indicates that their treatment systems are deficient in some
aspect of their design or operation (i.e. mill 132
inadequate aeration capacity, mill 122 - inadequate aeration
capacity, mill 100 - inadequate detention time).
Finding that the design and operation of the treatment
systems at the bleached kraft mills had more impact upon
final effluent qualities than influent qualities, an
analysis was made of the impact of the type of treatment
facilities upon final effluent. Tables 89, BO, 91 and 92
present influent and effluent data from mills using ASB'd,
A's, ASB's and A's without post storage ponds or clarifiers,
and Averages are ASb's and A's with post storage ponds or
clarifiers, respectively. Averages are presented in the
tables for all mills in each respective table and for the
best mills in each table as determined from the previous
discussions (i.e. Table 88 and Figure 68). The averages for
each table are summarized in Table 93 with the corresponding
number of mills which were used to determine the average.
It should be pointed out that the same mills were used to
determine the BODJ5 and TSS averages and the reason that
Table 93 shows less mills in the TSS column than the BOD5_
column is because several mills either did not have TSS data
available or measured TSS by non-standard analytical
techniques. Examination of the averages for the best mills
in Table 93 shows that mills with post storage ponds or
clarifiers following their ASB's or A's generally achieved
the lowest BOD]5 and TSS concentrations in their final
effluents. However, the differences in BODji are
insignificant among the four categories of treatment systems
which range from 22 mg/1 to 28 mg/1. Mills using A's only
achieved an average of 67 mg/1 of TSS but data were only
available for three mills, two of which apparently had
design deficiencies relating to TSS reduction. The most
significant difference between the capabilities of the
385
-------
TABLE 8Q
BLEACHED KRAFT MILLS
FINAL EFFLUENT CHARACTERISTICS
MILLS WITH ASB'S
Final
Effluent Flow
Mill
130
117
111
127
114
166
125
138
113
109
108
131
501
116
132
140
kl/kkg (kgal/ton)
256.0
204.0
142.0
233.0
179.0
126.0
108.0
133.0
141.0
157.0
231.0
159.0
199.0
140.0
81.3
80.5
(61.5)
(49.0)
(34.1)
(55.9)
(42.9)
(30.2)
(25.9)
(32.0)
(33.7)
(40.0)
(55.4)
(38.1)
(47.7)
(33.5)
(19.5)
(19.3)
Raw
Waste
mg/L
120
146
213
153
276
237
288
375
260
213
295
-
-
356
289
350
Final Effluent
BODS
Treatment
SB-ASB
C-ASB
C-ASB
C-ASB
C-ASB
C-ASB
C-ASB
C-ASB
C-ASB
C-ASB
C-ASB
C-ASB
C-ASB
C-ASB
SB-NAB
SB-ASB
kg/kkg
2.9
2.8
3.2
5.4
4.6
3.1
3.2
4.4
4.8
6.2
8.5
6.9
11.9
8.8
6.8
7.2
(Ibs/ton)
( 5.8)
( 5.5)
( 6.3)
(10.7)
( 9.2)
( 6.2)
( 6.3)
( 8.8)
( 9.6)
(12.4)
(16.9)
(13.7)
(23.8)
(17.6)
(13.5)
(14.4)
mg/1
11
13
22
23
26
27
29
33
34
37
37
43
60
63
83
90
TSS
kg/kkg
6.5
4.8
6.5
8.6
3.8
5.4
6.1
9.1
-
17.0
11.1
-
15.9
39.4
5.0
7.3
(Ibs/ton)
(13.0)
( 9.6)
(13.0)
(17.1)
( 7.5)
(10.8)
(12.1)
(18.1)
( - )
(34.0)
(22.2)
( - )
(31.7)
(78.7)
( 8.9)
(14.5)
mg/L
25
23
46
37
21
46
56
68
-
102
48
-
80
282
55
90
Subcategory
MKT
BCT
BCT
Diss.
MKT
Fine-BCT
BCT-MKT
BCT-MKT
BCT-MKT
BCT
Diss.
BCT-MKT
BCT-MKT
Fine
Fine
MKT
Average
(all
mills) 151 (38.7) 255
Average
(best
mills) 173 (41.6) 234
5.7 (11.3) 39
4.7 ( 9.3) 28
10.4 (20.8) 70
7.9 (15.7) 47
-------
TABLE 90
BLEACHED KRAFT MILLS
FINAL EFFLUENT CHARACTERISTICS
MILLS WITH A'S
co
Final
Effluent Flow
Mill kl/kkg (kgal/ton)
119 97.2
112 110.0
120 130.0
136 120.0
104 219.0
118 125.0
Average
(all
mills) 133
Average
(best
mills) 135
(23.3)
(26.4)
(31.2)
(28.7)
(52.5)
(30.0)
(32.0)
(32.4)
Raw
Waste
BODS
mg/L"
240
224
369
242
183
189
241
252
E
Treatment kg/kkg
C-A 1.1
C-ASB-C 1.5
C-A 3.6
C-A 3.8
C-A 7.3
C-A 8.2
4.3
3.5
Final Effluent
!OD5
(Ibs/ton)
(2.2)
(2.9)
(7.1)
(7.6)
(14.6)
(16.3)
( 8.5)
( 6.9)
mg/L
11
13
27
32
33
65
30
23
kg/kkg
3.3
15.4
13.8
29.9
13.6
13.5
14.8
10.2
TSS
(Ibs/ton)
( 6.5)
(30.7)N
(27.6)
(59.8)*
(27.2)
(26.9)
(29.6)
(20.4)
33
139
106
250
62
107
112
67
Subcategory
Fine
Fine
Fine-MKT
Fine
Fine-BCT
Fine
* Excluded from the average of the best.
N Non-standard methods TSS analytical measurement technique.
-------
TABLE '»'
BLEACHED KRAFT MILLS
FINAL EFFLUENT CHARACTERISTICS
MILLS WITH ASB's OR A's WITHOUT PS
CO
00
oo
Final
Effluent Flow
Mill
130
119
117
111
127
114
166
120
138
125
136
104
113
109
108
131
501
116
118
132
140
kl/kkg
256.0
97.2
204.0
142.0
233.0
179.0
126.0
130.0
133.0
108.0
120.0
219.0
141.0
167.0
231.0
159.0
199.0
140.0
125.0
81.3
80.5
(kgal/ton)
(61.5)
(23.3)
(49.0)
(34.1)
(55.9)
(42.9)
(30.2)
(31.2)
(32.0)
(25.9)
(28.7)
(52.5)
(33.7)
(40.0)
(55.4)
(38.1)
(47.7)
(33.5)
(30.0)
(19.5)
(19.3)
Raw
Waste
BOD5
rog/L
120
240
146
213
153
276
237
369
375
288
242
183
260
213
295
-
-
356
189
289
350
Treatment
C-ASB
C-A
C-ASB
C-ASB
C-ASB
C-ASB
C-ASB
C-A
C-ASB
C-ASB
C-A
C-A
C-ASB
C-ASB
C-ASB
C-ASB
C-ASB
C-ASB
C-A
SB-NAB
SB-ASB
Final Effluent
Average
(all
mills)
Average
(best
mills)
156
165
(37.4)
(39.7)
252
241
BODS
TSS
kg/kkg (Ibs/ton) mg/L
2.9
1.1
2.8
3.2
5.4
4.6
3.1
3.6
4.4
3.2
3.8
7.3
4.8
6.2
8.5
6.9
11.9
8.8
8.2
6.8
7.2
( 5.8)
( 2.2)
( 5.5)
( 6.3)
(10.7)
( 9.2)
( 6.2)
( 7.1)
( 8.8)
( 6.3)
( 7.6)
(14.6)
( 9.6)
(12.4)
(16.9)
(13.7)
(23.8)
(17.6)
(16.3)
(13.5)
(14.4)
11
11
13
22
23
26
27
27
33
29
32
33
34
37
37
43
60
63
65
83
90
kg/kkg (Ibs/ton) mg/L Subcategc
6.5
3.3
4.8
6.5
8.6
3.8
5.4
13.8
9.1
6.1
.25.4
13.6
-
17.0
11.1
-
15.9
39.4
13.5
5.0
7.3
(13.0)
( 6.5)
( 9.6)
(13.0)
(17.1)
( 7.5)
(10.8)
(27.6)
(18.1)
(12.1)
(50.8)*
(27.2)
( - )
(34.0)
(22.2)
( - )
(31.7)
(78.7)
(26.9)
( 8.9)
(14.5)
25
33
23
46
37
21
46
106
68
56
250
62
_
102
48
-
80
282
107
55
90
MKT
Fine
BCT
BCT
Diss.
MKT
Fine-BCT
Fine-MRT
BCT-MKT
BCT-MKT
Fine
Fine-BCT
BCT-MKT
BCT
Diss.
BCT-MKT
BCT-MKT
Fine
Fine
Fine
MKT
5.5 (10.9) 38
4.5 ( 8.9) 27
11.3 (22.6) 81
8.4 (16.8) 52
*Exclvded from the average of the best
-------
TABLE q2
BLEACHED KRAFT MILLS
FINAL EFFLUENT CHARACTERISTICS
MILLS WITH ASB's or A's with PS or C
CO
00
Mill
101
105
106
107
121
103
110
100
134
122
Average
(all
mills)
Average
(best
mills)
Flow
kl/kkg(kgal/ton)
159 (38.2)
162
171
187
158
171
100
155
93
123
148
158
(38.9)
(40.9)
(44.8)
(37.9)
(40.9)
(24.0)
(37.2)
(22.3)
(29.5)
(35.5)
(37.9)
BODS
mgA
182
224
204
264
189
232
277
293
332
367
256
225
Treatment
C-ASB-PS
C-ASB-PS
C-ASB-PS
C-A-PS
C-ASB-PS
C-ASB-PS
C-ASB-C
C-ASB-PS
C-ASB-C
C-ASB-PS
BODS
kg/kkg (Ibs/ton)
1.5 ( 2.9)
2.6
3.1
3.3
4.4
2.3
3.4
11.5
7.6
11.7
5.1
2.9
( 5.1)
( 6.2)
( 6.6)
( 8.7)
( 4.6)
( 6.8)
(22.9)
(15.1)
(23.3)
(10.2)
( 5.8)
9
16
18
18
28
31
34
74
81
95
40
22
TSS
kg/kkg
2.1
-
3.5
12.1
5.7
1.6
7.0
5.8
24.2
13.6
8.4
5.3
(Ibs/ton)
( 4.2)
( -)
( 6.9)
(24.1)
(11.3)
( 3.2)
(13.9)
(11.5)
(48.3)
(27.2)
(16.7)
(10.6)
13
-
20
64
36
21
69
37
260
111
70
37
Subcategory
Fine-MKT
BCT
Fine-MKT
Fine-MKT
BCT
Fine-MKT
Fine-MKT
BCT-MKT
Fine
BCT-MKT
-------
TABLE 93
BLEACHED KRAFT MILLS
FINAL EFFLUENT CHARACTERISTICS VS TYPE OF
TREATMENT FACILITIES
Type of
Treatment
g ASB
A
ASB & A
ASB/A & PS/C
ASB
A
ASB & A
ASB/A & PS/C
Flow
kl/kkg (kgal/ton)
All Mills
151
133
156
148
Best
173
135
165
158
(38.7)
(32.0)
(37.4)
(35.5)
Mills
(41.6)
(32.4)
(39.7)
(37.9)
BODS
255
241
252
256
234
252
241
225
BODS
kg/kkg(Ibs/ton)
5.7 (11.3)
4.3
5.5
5.1
4.7
3.5
4.5
2.9
( 8.5)
(10.9)
(10.2)
( 9.3)
( 6.9)
( 8.9)
( 5.8)
39
30
38
40
28
23
27
22
No. Of
Mills
16
6
21
10
12
5
16
7
TSS
kg/kkg(lbs/tOR)
10.4 (20.8)
14.8
11.3
8.4
7.9
10.2
8.4
5.3
(29.6)
(22.6)
(16.7)
(15.7)
(20.4)
(16.8)
(10.6)
«4/L
70
112
81
70
47
67
52
37
No. of
Mills
14
5
19
9
10
3
14
6
ASB Aerated Stabilization Basin
A Activated Sludge System
PS Post Storage
C Clarifier
-------
treatment systems is that mills using ASB's or A's with PS
or C achieved lower TSS concentrations (37 mg/1) than mills
using ASB's or A's (52 mg/1). However, the difference is
actually not very large and it appears that high quality
effluents can be achieved with any of the treatment systems.
Soda Mills
Two mills in the soda subcategory have biological treatment
facilities and the effluent data is summarized for these
mills in Table 94. Schematics of the treatment facilities
at these mills are shown in Figure 67. It should be pointed
out that mill 150 has recently shut down.
Mill 150 used a trickling filter system and did not achieve
comparable effluent qualities with mills using systems
representative of BPCTCA.
Mill ISO's BODJ5 and TSS concentrations were 222 mg/1 and 150
mg/1, respectively, and mill 152 achieved 28 mg/1 BOD5_ and
107 mg/1, respectively. The treatment facilities used by
mills 150 and 152 are not considered to be representative of
BPCTCA as indicated by the effluent qualities. The BOD5_
concentrations of mill 152 are high quality; however, the
TSS concentrations indicate deficiency in design and/or
operation of the treatment facilities. The mill treatment
system as displayed in Figure 67 consists of a clarifier
followed by an ASB with five days of detention time. The
ASB appears to have adequate aeration capacity for reduction
of BOD5_ but the detention time is much less than normal
design which appears to have significant impact upon TSS
concentrations in the final effluent. In addition, the
primary clarifier overflow rate of 38.7 klpd/m2. (950
gpd/ft2) is nearly 50% higher than design flow rates
considered to be representative of BPCTCA. This could
certainly have an effect upon the level of TSS in the final
effluent.
Groundwood Mills
Four groundwood mills have biological treatment systems,
mills 001, 002, 003 and 005. The effluent data for these
mills has been summarized in Table 95, and the schematics of
the treatment facilities are illustrated in Figure 67.
Mill 003 uses a trickling filter which does not achieve
effluent qualities comparable to the biological treatment
systems employed by the other groundwood mills. Two mills
have ASB's, mill 001 (SB-ASB-C) and mill 005 (SB-ASB) . The
detention times of these ASB's are eight days and the
391
-------
Table 94
Soda Subcategory
Final Effluent Characteristics
Final Raw
Effluent Waste Final Effluent
11 Flow BODS Treatment BQD5 TSS
kg/kkg(kgal/ton) mg/U kg/kkgTJbT/ton) mg/L kg/kkgTJb"s/ton) mg/
150 158 (37.9) 359 C-TF 35.1 (70.2) 222 23.7 (47.4) 15C
152 111 (26.6) 216 C-ASB 3.1 ( 6.2) 28 11.9 (23.7) 107
392
-------
TABLE 95
GRQUNDWOOD MILLS
FINAL EFFLUENT CHARACTERISTICS
Mill
001
003
005
s °02
CO
Final
Effluent
Flow
kl/kkg (kgal/ton)
91.8 (22.0)
106.3
97.6
98.4
(25.5)
(23.4)
(23.6)
Raw
Waste
BC05
mg/1 Treatment
529 SB-ASB-C
177 C-TF-C
183 SB-ASB
187 C-A
Final Effluent
POD5_
kg/kkg (Ibs/ton)
2.1 ( 4.1)
8.0
2.1
2.3
(15.9)
( 4.1)
( 4.6)
mg/1
22
75
21
23
TSS
kg/kkg (Ibs/ton)
3.2 ( 6.4)
7.9
2.5
7.3
(15.7)
( 4.9)
(10.8)
35
74
25
55
Subcategory
GW CMP
CW Fine
GW Fine
GW Fine
-------
systems are achieving high quality effluents. Mill 002 has
an activated sludge treatment system which discharges 23
mg/1 BOD5_ and 55 mg/1 TSS.
Deink Mills
The deink subcategory includes five mills which employ
biological treatment systems, Mills 203, 204, 206 and 216.
Final effluent characteristics for these mills are
summarized in Table 96 and the schematics of the treatment
systems are shown in Figure 67.
Mills 203 and 204 use clarifiers followed by aerated
stabilization basins. None of these systems are
representative of BPCTCA as indicated by the relatively high
levels of BOD5_ and TSS in the final effluents and by
analysis of the design and operations of the treatment
systems. Mill 203 "s treatment system is generally
underdesigned: the clarifier overflow rate of 30,557 Ipd/sq
m (750 gpd/sq. ft.) is higher than the normally accepted
design overflow rates of 20,371 Ipd/sq.m (500 gpd/sq.ft.) to
24,445 Ipd sq.m. (600 gpd/sq.ft.); the detention time of the
ASB of 7.2 days is less than adequate designs for the
strength of deink mill waste waters which would be between
eight to 14 days; and the ASB is underaerated with only 735
hp. Mill 204 uses an ASB with only 1.4 days of detention
time and 180 hp, both of which are inadequate for effective
reduction of the raw waste loads.
Mills 206 and 126 use a modified activated sludge system and
a conventional activated sludge system, respectively. Final
effluent characteristics are shown in Table 96, and it
appears that mill 216 was experiencing difficulties of
solids capture in the secondary clarifier even though the
primary and secondary clarifier have design overflow rates
better than the above normally accepted rates. The
importance of primary clarification in achieving effective
reductions in raw waste load prior to biological treatment
has been demonstrated by mill 217. Mill 217 employs only
primary treatment using a clarifier with design overflow
rates of 15,367 Ipd/sq.m. (377 gpd/sq.ft.) and removes
nearly two-thirds of the raw waste BOD5_.
Sulfite Mills
Effluent data for the nine mills in the sulfite
subcategories that have biological treatment data are
presented in Table 97. As shown on the table, several items
should be noted when evaluating the raw waste and final
effluent data from these mills. Mills 006 and 007 have
394
-------
Table 96
Deink Mills
Final Effluent Characteristics
OO
-------
CTi
Table 97
Sulfite Mills
Biological Treatment Data
Influent to Treatment
Effluent from Treatment
Mill
a/
006"
a/
007"
051
052
053
a/
073
d/
184"
401
512
a/
b/
c/
d/
e/
Treatment
ASB
ASB
ASB
ASB
A
c/
OA
£./
OA
ASB-C
c/
OA
Includes groundwood pul
Non-standard method
Oxygen activated sludge
Includes bleached kraft
Oxygen activated sludge
BOD 5, mq/1
377
281
388
432
2645
497
277
3630
654
ping
pilot plant
and NSSC pulping
treatability studies
BOD5, mg/1
57
51
65
96
70
42
27
83
48
TSS, mg/1
b/
95
b/
62
60
b/
39
94
84
56
—
65
Subcategory
Papergrade
Papergrade
Papergrade
Papergrade
Papergrade
Papergrade
Papergrade
Dissolving
Dissolving
-------
groundwood pulping operations on-site and the waste water
from both the sulfite and groundwood pulping operations are
combined and discharged to the biological treatment system.
These mills are included in the sulfite table since the raw
waste load is much more significantly affected by the
sulfite operation than the groundwood operation. Mill 073
also has groundwood pulping; however, the impact of the
groundwood wastes on the total mill raw waste load is less
significant than at mills 006 and 007 because the percentage
of total groundwood pulp of the total mill production is
less. Mill 052 produces papergrade high yield unbleached
products and thus is not necessarily representative of
papergrade sulfite mills. In addition, the treatment system
at mill 052 is presently underdesigned and therefore the
effluent data is not indicative of BPCTCA. Mill 053 has
separate treatment systems for the pulp mill wastes and the
paper mill wastes. Mill 401 is a dissolving sulfite mill
that only treats a portion of the mill waste waters. Data
for mills 073 and 512 came from extensive pilot plant
investigations utilizing oxygen activated sludge. At mill
073 the total mill discharge was treated whereas at mill 512
only a portion of the total mill discharge was treated.
Data for mill 184 came from treatability studies performed
utilizing oxygen activated sludge. Mill 184 has bleached
kraft as well as NSSC pulping operations which contribute to
the raw waste load.
The treatment systems in use at the present time by sulfite
mills primarily include aerated stabilization basins.
However, many sulfite mills without biological treatment are
investigating systems employing air activated sludge and
oxygen activated sludge. These systems offer many
advantages such as reduced land requirements and operational
flexibility. In addition to data from full scale biological
treatment systems presently in use, extensive pilot plant
studies have been conducted at a number of sulfite mills,
and data have been used from these mills where extensive
data were available. Schematics of mill external treatment
systems are presented in Figure 67. Evaluation of the
design parameters of the aerated stabilization basin at mill
052 show that the system is underdesigned. For these
reasons the effluent data from this mill were not used in
determining effluent BODY'S attainable with biological
treatment. Table 98 presents biological treatment influent
vs. effluent (BOD5) data.
Because of the limited number of mills with adequated
designed and properly operated biological treatment systems
and in order to include as much data as possible in the
development of the effluent limitations, all available
397
-------
TABLE 9R
SULFITE MILLS
BIOIJOGICAL TREATMENT: INFLUENT vs. EFFLUENT (BOD5)
Mill Influent BODS, nq/1 Effluent BODS, mg/1
006 377 57.0
007 281 51.0
051 388 64.7
053 2645 70.0
073 298 36.0
073 625 58.0
073 548 48.0
073 444 23.0
073 534 32.0
073 432 42.0
184 • 286 34.0
184 267 20.0
401 3630 83.0
512 727 74.6
512 774 58.0
512 574 49.5
512 622 34.1
512 648 41.0
401 4210 138.0
401 4099 142.0
401 3897 190.0
401 1984 76.0
401 1962 102.0
401 1475 84.0
398
-------
biological treatment data from mills using either full scale
and pilot plant biological treatment systems were included
in the analyses which were used as a basis for the effluent
limitations for the sulfite sutcategories. Table 98
presents all available influent and effluent BOD5 data from
sulfite mills using either a full scale biological treatment
system or a pilot plant system. It should be noted that
several data points are shown in the table for the same
mills. This is a result of different operating conditions
at the mills. A regression analysis was perfromed on the
data and it was determined that the best fit of the data is
described by the following relationship:
Log BOD5 Eff = O.U96 Log BOD^ Inf + 0.309
BOD?> Eff = Concentration of final effluent BODjj
BOD5 Inf - Concentration of biological treatment
influent BOD5
The data in Table 98 is graphically displayed in Figure 70.
In order to further substantiate the above relationship for
sulfite mills, all available BOD5 data for mills in other
subcategories using biological treatment systems were
examined to determine a corresponding relationship between
influent and effluent BODj> levels. It should be noted that
this data analysis used data from mills using only full
scale biological treatment systems, because many more mills
in the other subcategories use full scale biological
treatment systems and data were available. The data is
presented in Table 99 and is graphically displayed in Figure
71. A regression analysis was performed on the data (all
data including sulfite data) and the following relationship
was determined to represent a best fit of the data:
Log BOD5 Eff = 0.601 Log BOD5 Inf -0.020
BOD5 Eff = Concentration of final effluent BODj>
BODj> Inf = Concentration of biological treatment
influent BOD5
Comparison of effluent levels predicted by the two
relationships using the same influent values shows that
lower effluent levels (or better treatment efficiencies) are
predicted by the relationship which used all of the data.
Therefore, the data from sulfite mills represents a lesser
degree of treatment than the data in Table 99 from other
mills which are in the bleached kraft, groundwood, and deink
subcategories.
399
-------
2.5
2.0
O
o
CQ
fc:
§1.5.
Figure 70
Sulfite Mills
Biological Treatment: Influent vs. Effluent
Log BOD5 Eff=0.496 Log BOD5 Inf. + 0.309
1.0
I
2.0
2.5
3.0
LOG INFLUENT BOD5
3.5
.0
-------
TABLE 99
INFLUENT VS. EFFLUENT: BODS
BEST MILLS
Influent Effluent
BODS BODS
Mill mg/L mg/L
127 131 23
108 295 37
114 276 26
130 120 11
105 224 16
109 213 37
111 213 22
121 189 28
117 146 13
113 260 34
138 375 33
125 288 30
119 240 11
103 223 34
136 242 32
106 204 18
166 237 27
101 182 9
107 264 18
104 183 33
110 277 34
120 369 27
001 205 22
005 183 21
002 187 23
206 683 51
216 687 52
Note: Mills 001, 005, 002 are Groundwood mills; Mills 206, 216 are
deink mills; and the rest of the mills are bleached kraft mills.
401
-------
FIGURE 71
INFLUENT VS. EFFUOT BODS: BEST MILLS
2.25.
2.00-
1.00
0.75
2.00
2.25
2. 50
log eff = 0.601 to? Inf - 0.020
A Bleached Kraft
D Groundwood & Deink
o Sulfite
2.75 3.oO
IJOG INFUUENT BOD
3. 25
3.50
3.75
40
-------
NI Fine Paper Mills
The NI fine paper subcategory includes two mills with
biological treatment, Mills 257 and 284. Effluent
characteristics are given in Table 100.
Neither mill is achieving relatively high quality effluent
BOD5_ and TSS. Mill 257 has an activated sludge system;
however, the primary clarifier is under designed (overflow
rate equals 32,630 Ipd/m2 (801 gpd/ft2)). Mill 284 uses a
rotating biological surface (RBS) but does not achieve high
quality effluent. Even though the RBS at mill 284 does not
achieve effective reduction of the raw waste load, the final
effluent qualities are less than the effluent limitations.
Mill 284 uses inplant controls as an alternative to
effective external treatment and achieves a lower than
average raw waste flow rate. The mill is presently
achieving the effluent limitations (on a kg/kkg (Ibs/ton)
basis) through the combination of good internal controls and
some external treatment.
Other mills in the subcategory use only primary treatment.
However, mill 261 with a clarifier and conservative water
usage (similar to mill 284) achieves a BODj> discharge of
1.65 kg/kkg (3.3 Ibs/ton) which is substantially below the
2.4 kg/kkg (4.8 Ibs/ton) upon which the limitation is based.
NI Tissue Mills
The NI tissue subcategory limitations are based upon primary
treatment. Table 101 summarizes the effluent
characteristics of NI tissue mills for which data were
available. Treatment systems used by these mills include
clarifiers, settling basins, and dissolved air flotation.
All of the above treatment systems are considered capable of
achieving BPCTCA levels. Only one mill's treatment system
was substantially inadequate; Mill 325 which has a DAF and a
resultant effluent BOD5> load 5 times higher than the
average. DAF treatment systems can be used to attain low
levels of BODJ5 as illustrated by Mill 306 which discharges
the lowest BOD5> load of the NI tissue mills.
The identified external treatment system for the NI Tissue
Papers (fwp) subcategory includes biological treatment
because of the higher amounts of soluble BOD!3 in the raw
waste load from mills using waste paper as their source of
fiber. NI mills producing tissue from purchased pulp are
able to obtain relatively effective primary treatment since
most of the BODj> in the raw waste load is associated with
the fibrous materials in the raw waste. However, the use of
403
-------
o
-e»
TABLE
NI FINE PAPERS SUBCATEGORY
FINAL EFFLUENT CHARACTERISTICS
Mill
266
261
257
255
250
281
275*
265
284
277
279
274
Raw
Waste
Flow BODS
kl/kkg (kgal/ton) mg/1
49.2 (11.8) 260
26
40
37
.3
.9
.9
53.8
73
90
69
25
80
37
138
.0
.5
.2
.8
.5
.5
.0
( 6
( 9
( 9
(12
(17
(21
(16
( 6
(19
( 9
(33
.3) 329
.8) 229
.1)
.9)
.5)
.7)
.6) 162
.2) 294
.3) 201
.0)
.0) 52
Treatment
C
C
C-A
C
SB
SB
C
C
C-RBS-C
C
SB
SB
BODS
kg/kkg (Ibs/ton)
4.4 ( 8.7)
1.7
3.4
-
4.8
2.6
14.7
5.6
2.9
10.6
8.7
4.6
( 3.3)
( 6.7)
( - )
( 9.7)
( 5.2)
(29.3)
(11.2)
( 5.7)
(21.1)
(17.3)
( 9.1)
mg/1
88
63
82
-
90
36
162
81
110
131
230
33
TSS
kg/kkg (Ibs/ton)
1.3 ( 2.6)
-
2.4
6.3
0.8
1.7
11.7
-
2.7
-
7.4
2.0
( - )
( 4.8)
(12.5)
( 1.5)
( 3.4)
(23.4)
( - )
( 5.3)
( - )
(14.7)
( 4.0)
mg/1
26
-
59
165
14
23
129
-
102
-
196
14
* 20% Deink
-------
TABLE 101
NI TISSUE PAPERS MILLS
FINAL EFFLUENT CHARACTERISTICS
Raw Waste
Final Effluent
30B
325
318
315
306
252
319
208
329
302
310
324
309
333
259
326
330
313
A:
8:
Flow BODS
kl/kk9(kgal/ton) kg/kkgQbs/ton) mg/L
115.5 (27.7) 16.7 (33.4
130,9 (31.4)
140.5 (33.7) - (
66.3 (1!
43.4 1!
48.0 1
120.1 21
145
_
-
j.9 8.7 (17.4) 131
3.4
.5
3.8 7.3
-
'
14.7 61
61.3 (14.7) 22.8 (45,7) 373
153.9 (36.9)
-
50.9 (12.2) 11.7 (23. S
96.7 (23.2) 7.4
94.7 (22.7) 13,6
[14.8
27.3
231
76
144
69.6 (16,7) 14.6 (29.3) 210
133.4 3
73.8 1
2.0)
7.7) 9.6
72.6 (17.4)
- 1
19.2
79.2 (19.0) - ( -
27.9
5.7)
, -
130
.
-
-
TSS
kg/kkg(1bs/ton) mg/L
30.1
.
.
25.7
.
_
35.8
72.0
.
60.3
51.5
71.7
145
™
36.6 ( 73.3
22.4
44.8
51.5 (103.0
25.2
32.1
.
-
50.4
64.3
-
261
N 388N
N 299N
1180
N 720N
232
544
N 362N
436
-
Treatment
C
OAF
C
DAP
OAF
C-PS
SB
C
C
C-PS
C
SB
C
C
C.OAF
C
C
C-PS
BflDS
TSS
kg/kkg(lbs/ton mg/L kg/kkg(lbs/t
4.5 ( 9.1
17,5
3.5
4.4
1.0
3.4
2.5
6.2
6.1
35.1
7.1
39
134
25
3.8
-
4.6
8.9) 67
2.0
6.9
5.0
12.4
12.2
1 23
72
i 21
101
40
-
1.1
.
7.7
9.3
w
2.2
m
3.2 (6.4
3.5 (7.1
3,3 ( 6.6) 65 - { -
2.7
5.5) 28
1.4 ( 2,8) 15
1,9
4,8
3.8
9.6
3.9 ( 7.9
2.4 4.9
) 27
i 36
i 54
34
3.0
1.5 (3.0
1.9
11.6 (23.2) 146
11.5 (23.0) 411
_
.
3.9
•*
»
33
33
23
52
23
31
16
26
Subcategory
A
A
A
A
A
A
A
A,B
A,B
A,B
A.B
A,B
A.B
A,B
A.B
A.B
B
B
NI Tissue Papers
N! Tissue Papers (FWP)
-------
waste paper results in higher amounts of soluble BOD5 (from
papermaking additives - i.e., starch) in the raw waste which
require biological oxidation to be effectively removed.
The need for biological treatment is demonstrated by mills
330 and 313 which employ only primary treatment for effluent
reduction. As shown in Table 80 in Section V, the primary
effluent qualities from both mills are approximately 11.5
kg/kkg (23.0 Ibs/ton) of BOD5 which is equal to the NI
Tissue Papers Subcategory raw waste load. Thus, further
reductions by biological treatment are required in order to
achieve high quality effluents. None of the four mills in
the NI Tissue Papers (fwp) subcategory for which data were
available presently employ biological treatment systems.
Variability of Effluent Discharges from Surveyed Mills
Because of the wide variety of factors which impact on the
performance of biological treatment concepts employed by the
various mills, an analysis was conducted to quantify as much
as possible any variability attributable to these factors.
It is apparent that the treated effluent from pulp and paper
mills varies on a daily basis. The extent of the variation
is illustrated by Figure 72 which gives the effluent BOD5_
from an ASB for mill 117. The effluent from properly
designed and operated waste treatment may vary due to a
variety of factors including changes in raw materials,
production rates, final product, climatic conditions,
treatment system operation, and sampling and analysis
techniques. As a general matter, variability in the extreme
is due to the coincident impact of several of these factors
simultaneously or a major spill or climatic catastrophe.
A common indicator of the pollution characteristics of the
discharge from a plant is the long-term average of the
effluent load, which has been used as a point of departure
in the variability analysis and subsequently in developing
the annual average basis for the effluent limitations.
Statistical analyses can be used to compute short-term
limits (30 day average or daily) which should not be
exceeded, provided that the plant is designed and run in the
proper way to achieve the desired long-term average load.
Variability associated with properly designed and operated
treatment plants was assessed using statistical analyses of
all plants where sufficient data were available to determine
these variances for day-to-day and 30 day operations.
Maximum thirty-day averages were examined by calculating the
"moving" thirty calendar day averages (each 30 day period
406
-------
FIGURE 72
DAILY EFFLUENT BODS DATA FOR MILL 117
o
•xj
z
o
II.O -
iO.O -
9.0 -
8,0 -
7.0 -
6.0 -
in
™ 5.0-
4.0 -
3.0 -
2.0 -
1.0 -
0.0
«/***
*
» t
,*» *
* * *
. ** * * **
OCT
31 3O 31 31
NOV DEC JAN FEB
28
MAR
31
APR
MONTHS
-------
contained at least 8 days of data before the average was
calculated). The maximum 30 day average divided by the
annual average for each plant was then examined.
Daily maxima were examined from the following approaches:
(a) Actual Daily Maximum
(b) Normal Probability
(c) Log Normal Probability
(d) Three Parameter Log Normal Probability
The actual daily maximum approach was found to fail to
incorporate all relevant elements of the data set and did
not permit derivation of a meaningful confidence level.
Normal probability consistently yielded positive
coefficients of symmetry which underestimates excursions
whereas, log normal probability consistently yielded
negative coefficients of symmetry which tend to over-
estimate excursions. For accurate predictions of excursions
using normal or log normal probability the distribution
should be symmetric, that is the coefficient of symmetry
should be zero. By adding a constant to the data set prior
to log normal probability analysis the symmetry can be
adjusted to zero and the resultant predictions using this
analysis (3 parameter log) is more accurate than normal or
log normal analyses. A summary of the resultant variability
factors is presented in Table 102. An "A" or "B" following
a mill code indicates a more recent data set with the "B"
data being the most recent.
In order to account for process differences, variability was
separately analyzed for bleached kraft, groundwood, sulfite,
deink, soda, non-integrated tissue papers, and non-
integrated fine paper mills. The results of these analyses
were that bleached kraft had the highest variabilities of
the integrated mills. Inasmuch as all of the other process
groups failed to have as many plants with biologocal
treatment and that a broader data range for assessing the
variability of some of the process groups is desirable, a
comparison was made between the variability of different
process groups. Although the higher variability sets from
soda, deink, sulfite, and groundwood are less than the upper
level values of the bleached kraft variability numbers, the
variability sets of soda, deink, sulfite and groundwood are
not statistically different from bleached kraft. Since the
variability of pulp and paper mill effluent from biological
treatment did not appear to be due to differences in process
type, the data sets were combined into a single set for the
last step of variability analysis which thereby expanded the
variability basis.
408
-------
TABLE 102
EFFLUENT VARIABILITY RATIOS
Mill
Code
1
1A
IB
2
2A
2B
3
4
4A
5
SB
6
7
8
9
10
13
13A
14
51
52
53
100
100B
101
101A
10 IB
103
10 3A
10 3B
104
105
106
107
107A
107'
108
108.
109
110
BODs Daily
Variability Ratio
BODs 30-Day
Variability Ratio
Annual Average BOD?
kg/kkg(Ibs/ton)
32
36
61
48
07
70
68
71
71
87
46
21
89
60
28
29
03
57
79
12
64
59
29
19
42
58
33
4.03
02
54
2.13
98
58
52
31
62
19
88
2.27
1.66
2.56
2.13
2.27
-
1.33
1.33
-
2.29
-
1.73
1.44
-
-
-
1.45
-
1.24
1.55
1.28
1.78
2.68
-
2.39
1.34
-
2.35
_
1.73
1.52
2.81
1.52
1.71
-
1.31
-
1.42
1.72
2.06
0.76
1.00
2.81
3.58
2.28
7.95
3.39
4,46
2.36
2.04
4.57
4.97
17.7
15.7
21.5
7.72
9.35
5,95
14.0
16.3
1.74
14.2
11.4
1.25
2.95
1.47
11.8
8.50
6.65
2.55
4.60
2.90
2.70
3.30
9.15
8.45
6.50
3.15
( 4.12)
( 1.52)
( 1.99)
( 5.61)
( 7.15)
( 4.55)
(15.9 )
( 6.78)
( 8.91)
( 4.71)
( 4.07)
( 9.14)
( 9.93)
(35.49)
(31.43)
(42.98)
(15.44)
(18.7 )
(11.9 )
(28.0 )
(32.5 )
( 3.47)
(28.4 )
(22.9 )
( 2.5 )
( 5.9 )
( 2.93)
(23.5 )
(17.0 )
(13.3 )
( 5.1 )
( 9.2 )
( 5.8 )
( 5.4 )
( 6.59)
(18.3 )
(16.9 )
(13.0 )
( 6.3 )
TSS Daily
Variability^ Ratio
2.89
2.94
5.76
5.99
5.37
2.70
4.95
2.88
2.88
2.35
2.95
2.66
6.65
2.13
63
94
44
96
39
3.12
2.59
2.73
2,17
2.34
3.86
TSS 30-Day
Variability Ratio
1.81
2.34
2.57
1.62
2.19
1.75
2.00
1.24
2.02
1.16
1.80
1,58
1.82
2.01
2.14
2.54
Annual Average TSS
kg/kkg (Ibs/ton)
3.20 ( 6.4 )
2.29
7.87
6.90
5.41
7.53
1.88
2.29
2.22
( 4.57)
(15.74)
(13.8 )
(10.8 )
(15.06)
( 3.75)
( 4.57)
( 4.43)
2.47 ( 4.93)
-
_
1.48
5.73
1.35
2.25
2.1
4.75
-
3.84
12.3
4.70
12,1
11.1
7.10
(21.8))
( 2.56)
( 2.96)
(11.5 )
( 2.7 )
( 4.5 )
( 4.2 )
( 9.5 )
( 2.7 )
( 7.67)
(24.6 )
( 9.4 )
(24.1 )
(22.2 )
(14.2 )
-------
EFFLUENT VARIABILITY RATIOS
(Oont.)
MiU
Oode
11QA
111A
U1B
112
113
113A
114
114A
116
116B
117
117A
118
119
120
121
122
125
12 7A
127B
134
136
140
150
152
203
204
205
205B
206
207
208
252
254
255
256
257
257A
BOD5 Daily
Variability Ratio
1.81
15
24
15
40
4.49
58
68
78
97
06
10
2.44
2.32
2.48
3.35
3.12
62
06
2.13
64
88
56
48
94
44
55
37
60
94
04
2.01
6.77
2.37
BCDs 30-Day
Variability Ratio
1.51
1.51
1.19
2.57
Annula Average BOD 5
kg/kkg(lbs/ton)
95
54
71
1.16
76
65
78
49
52
78
69
2.14
1.85
1.49
1.42
1.37
1.60
,72
,27
.18
79
,26
1.55
1.56
1.44
3.70
3.17
1.45
4.55
4.98
6.30
2.95
8.75
8.80
2.20
2.85
5.75
1.10
3.55
4.60
6.75
3.25
6.80
5.35
7.55
3.80
7.2
35.2
12.6
14.8
5.95
5.05
4.19
3.15
23.6
7.10
3.45
4.48
6.80
4.61
3.45
( 7.4 )
( 6.34)
( 2.9 )
( 9.1 )
( 9.95)
(12.6 )
( 5.9 )
(17.5 )
(17.6)
( 4.4 )
( 5.7 )
(11.5 )
( 2.2 )
( 7.1 )
( 9.2 )
(13.5 )
( 6.5 )
(13.6 )
(10.7 )
(15.1 )
( 7.6 )
(14.4 )
(70.3 )
(25.1 )
(29.6 )
(11.9 )
(10.1 )
( 8.38)
( 6.3 )
(47.1 )
(14.2 )
( 6.9 )
( 8.95)
(13.6 )
( 9.22)
( 6.9 )
IBS Daily
Variability Ratio
2.68
2.30
2.21
2.76
2.92
1.89
1.82
3.38
2.45
2.99
3.32
4.91
3.33
1.88
2.38
2.68
2.01
2.95
2.60
7.65
3.16
3.94
TSS 30-Day
Variability Ratio
1.72
1.28
1.59
1.27
.55
,00
.03
,31
.82
.63
1.26
1.32
1.46
1.57
3.61
1.81
Annual Average TSS
kg/kkg(lbs/ton)
6.75 (13.5 )
6.75 (13.5 )
6.5 (13.0 )
2.90
3.75
40.9
39.4
2.58
11.3
10.9
0.87
( 5.8 )
( 7.5 )
(81.8 )
(78.7 )
3.25 ( 6.5 )
6.65
5.95
6.05
7.95
8.55
24.1
29.9
7.25
(13.3 )
(11.9 )
(12.1 )
(15.9 )
(17.1 )
(48.2 )
(58.8 )
(14.5 )
24.8 (49.6 )
( 5.16)
(22.5 )
(21.8 )
( 1.73)
9.10 (18.2 )
-------
TABLE 102
EFFLUENT VARIABILITY RATIOS
(Cone.)
Mill
Code
259
261
262
262A
263
264
265
266
266A
269
271
277
284
302
303
306
308
309
310
313
315
318
325
329
333
350
351
353
357
358
361
382
359
BODS Dally
Variability Ratio
2.37
4.78
1.94
2.42
3.07
1.37
2.66
2.31
.54
.06
.87
.00
.83
.86
.54
2.51
2.90
2.91
3.21
08
60
34
48
70
82
28
32
25
77
37
4.46
3.16
BODS 30-Day
Variability Ratio
1.57
1.15
1.75
1.37
1.50
1.27
1.48
Annual Average BOD5
kg/kkg(lbs/tDn)
1.19
1.40
1.15
1.30
1.33
1.57
1.30
1.99
1.67
3.56
3,80
1.57
5.60
6.20
4.35
0.85
7.15
10.60
2.85
3.30
5.45
1.02
4.95
1.80
2.80
11.50
4.45
3.55
17.60
6.10
4.80
1.84
4.75
6.80
0.23
5.45
4.99
5.45
3.65
( 3.97)
( 3.33)
( 7.11)
( 7.60)
( 3.14)
(11.20)
(12.40)
( 8.70)
( 1.70)
(14.30)
(21.10)
( 5.69)
( 6.60)
(10.90)
( 2.03)
( 9.90)
( 3.60)
( 5.60)
(23.00)
( 8.90)
( 7.10)
(35.10)
(12.20)
( 9.60)
( 3.68)
( 9.50)
(13.60)
( 0.46)
(10.90)
( 9.97)
(10.90)
( 8.30)
TSS Daily
Variability Ratio
2.88
2.03
3.46
2.33
2.20
2.83
2.64
2.53
3.02
4.05
3.60
2.55)
9.61
7.18
TSS 30-Day
Variability Ratio
1.64
1.22
2.20
1.28
1.28
1.63
1.58
1.63
1.47
1.76
1.34
4.03
2.29
Annual Average TSS
kg/kkg(Ibs/ton)
1.22 ( 2.44)
2.28 ( 4.56)
1.01 ( 2.02)
1.31 ( 2.62)
4.60 ( 9.20)
5.20 (10.40)
2.65 ( 5.30)
5.60 (11.20)
3.01 ( 6.01)
4.65 ( 9.30)
3.55 ( 7.10)
0.92 ( 1.83)
5.20 (10.40)
5.85 (11.70)
-------
Figure 73 illustrates that daily variability of BODjj for
individual mills. The analysis was used to quantify a
relationship such that mills with activated sludge or
aerated stabilization basins regardless of climate or
process type under proper design and operation will
discharge a reasonably consistent effluent quality. As
illustrated by Figure 73, the daily BODjj variability level,
3.42, was exceeded by 5 mills; however, documentation of the
reasons for the "outliers" was available. In a similar
manner TSS daily variability was examined as shown in Figure
74. Seven variability points do exceed the variability
limit, 3.38. Recent data from mill 101 slightly exceeds the
TSS daily maximum variability ratios; however, this mill
operates a hold and release system and is not subject to the
daily maximum (kg/kkg (Ibs/ton)) effluent limitations. It
should be noted that three mills which exceeded the
variability limit for one year of data improved with time so
that more recent data has a variability less than the
variability basis; two variability points are attributable
to mill 002 which has had sampling and ammoniator problems;
and the three remaining mills have excessive BOD5 discharge
and require treatment system upgrading. Figure 75
illustrates the derivation of the 1.78 variability basis for
the BOD5> maximum 30 day average. All major deviations from
the majority of mills are explained by system failure,
system changes, or demonstrated improvements that have
occurred. One treatment system showed a value well beyond
the acceptable BOD5 annual average and therefore needs
upgrading.
The TSS maximum 30 day average variability ratio, 1.82, (see
Figure 76) (in the range of TSS annual average basis) has
some outliers one of which showed significant improvement
with additional data; two had documented system failure; the
rest are excluded due to inadequate treatment, i.e., mill
100 has apparent deficiencies in treatment (only four days
detention in the ASB).
In addition to specific processes, consideration was given
to variability due to location or treatment system. This
was examined as illustrated by Table 103 which presents the
variability of mills with activated sludge processes, the
identified treatment system for northern climates.
Activated sludge variability appears consistent with the
levels predicted resulting from the examination of all mills
with biological treatment and only one outlier exists, 30
day TSS for mill 197. All other values are within the
range. The most recent data for mill 107 which were
analyzed for the TSS daily maximum resulted in a daily
412
-------
Figure 73
Daily Maximum BOD5_
Variability of Pulp and Paper Mill Effluents
> Indicates going from one
data set to a more recent data
set for the same mill.
a - Process and treatment
changes (mill 001)
b - Sampling and ammoniator
problems (mill 002)
c - Aerator failures
d - Aerator failures
e - Clarifier outage
(mill 113)
(mill 106)
(mill 114)
16
17
Annual Average BODS (Ibs/ton)
-------
6.5
6.0
5.5
£ 5.0
4.5
4.0
3.5
3.0
2.5
2.0
0
Figure 74
Daily Maximum TSS
Variability of Pulp and Paper Mill Effluents
» a
Variability Basis
*
*
8 10 12 14 16 18 20 22 24 26
Annual Average TSS (Ibs/ton)
Indicates going from one
data set to a more recent
data set for the same mill
a-- Inadequate treatment
(Mill 100).
b - Sampling and ammoniator
problems (Mill 002).
c - Operating Procedures
(Kill 127)
-------
o
4J
10
ce
>,
2.8
2.6 L
2.4
2.2
L 2.0
10
£
10
> 1.8
1.6
1.4
1.2
1.0
Figure 75
Average 30 Consecutive Days
BOD5_ Variability of Pulp and Paper Mill Effluents
• e
Indicates going from
one data set to a more
recent data set for the
same mill.
a - Process and treat-
ment changes (Mills 1)
b - Aerators shut down
to conserve energy
(Mill 125).
c - Sampling and arnmoni-
ator problems ( Mill 2)
d - Aerator failures
(Mill 113).
e - Aerator failures
(Mill 106).
* Variability Basis
0
7 8 9 10 11 12
Annual Average BOD5_ (Ibs/ton)
13
14
15 16
17
18
-------
2.8 |_
2.6
° 2.4
4->
$ 2.2 -
4° 2.0
s_
IO
1.8
Figure 76
Average 30 Consecutive Days
TSS Variability of Pulp and Paper Mm Effluents
Indicates going from one
one data set to a more
recent data set from the
same mi 11.
a - Inadequate treatment
system (Mill 100}
b - Inadequate treatment
system (Mill 4)
c - Aerator failures (Mill
106).
d - Sampling and ammonlator
problems (Mill 2}
Variability Basis
1.6
1.4
1.2
1.0
u »
• •
*
*
i i i 1 i i » i i i i I i i
10 12 14 16 18 20 22 24
Annual Average TSS (Ibs/ton)
26
-------
TABLE 103
VARIABILITY OF MILLS WITH
ACTIVATED SLUDGE TREATMENT SYSTEMS
Mill
Code
104
107
112
118
119
257
Daily BOD_5
Variability
Ratio
2.54
2.58
3.24
3.10
2.44
2.37
30 Day Average
BOD5^ Variability
Ratio
1.73
1.52
1.19
1.78
1.49
1.56
Daily TSS
Variability
Ratio
2.59
3.22
-
-
3.38
_
30 Day Average
TSS Variabilit.
Ratio
1.82
2.14
-
-
1.55
_
417
-------
maximum variability ratio of 2.17. This strongly indicates
that the maximum 30 day average variability factor will be
substantially less than 1.82.
In a similar manner, non-integrated mills were analyzed for
variability. The NI fine papers subcategory does not
contain any mills with properly designed and operated
biological treatment systems. Since the recommended
treatment for NI fine paper mills is biological treatment,
the variability factors established for soda, deink,
sulfite, groundwood and bleached kraft mills (for whick the
recommended treatment is also biological treatment) were
also applied to NI fine paper mills. Analyses of the
variability of NI fine mills with biological treatment and
mills with primary treatment (achieving BOD5 and TSS levels
less than the subcategory annual average bases) indicated
there was little difference in variability from the
integrated mills. It should be noted that variability
factors for NI Fine, if considered separately, are generally
lower than those used for the integrated mills.
Because of basic treatment system differences (i.e., primary
versus biological), non-integrated tissue mills were
analyzed separately. The approach setting forth the
variability limit is the same as the integrated mills.
Figures 77, 78 79 and 80 illustrates the variability of
these mills.
An analysis was conducted to evaluate whether differences in
influent variability between mills accounts for differences
in effluent variability between mills. Table 104 compares
influent and effluent daily BOD5 variability for all
surveyed mills with raw waste load and final effluent data.
Examination of the influent versus effluent variability does
not yield any observable relationships that would indicate
influent variability should be directly used in deriving
effluent variability relationships.
The variability ratios developed are shown in Table 105.
In this course of simultaneously accounting for differences
in processes, climate, treatment systems, sampling accuracy
and the like, the ultimate predicted variability is manifest
of a practical extreme case. The confidence that the daily
variability limit will not be exceeded is greater then 99X
for most all cases and does exceed 99.9% for a number of
mills. For example, the following bleached kraft data sets
exceeded the 99.9% confidence level for the established
daily BOD5_ variability level: 101A, 105, 108, 109, 110,
110A, 111A, 116, 117, 117A, 119, 121, 122, 134 and 136 -
418
-------
6.0
5.5
o 5.0
4.5
S 4.0
s_
-------
Figure 78
Dally Maximum TSS
Variability of NI Tissue Paper Mills
a - Numerous clarifier
failures (Mill 318).
ro
o
9
8:
7
6
5
4
3
2
1
0
Variability Basis
J L
_L
456789
Annual Average TSS (Ibs/ton)
10 11 12
-------
Figure 79
Average 30 Consecutive Days
Variability of NI Tissue Paper'Mills
a - Treatment start-up
and experimentation (Mill 308),
2.0
1.8
1.6
S 1.4
1.2
1.0 i i i
Variability Basis
J I I L
23456 7
Annual Average BOD5/ton
10
-------
Figure 80
Average 30 Consecutive Days
TSS Variability of NI Tissue Paper Mills
ro
r\>
2.2
° 2.0
1.8
.a
* 1.6
1.4
1.2
1.0
Variability Basis
J_
4 5 6 7 8 9 10
Annual Average TSS (Ibs/ton)
11
-------
Table 104
Daily BOD5_ Variability Raw Waste vs Final Effluent
Mill
Code
001
002
003
004
005
051
100
101
103
104
105
108
110
124
125
150
152
203
204
253
257
258
260
261
264
265
270
302
303
308
309
315
Raw Waste
Variability*
Final Effluent
Variability*
,31
,20
.48
,70
,60
,95
,23
,90
,70
,85
,78
,76
,05
.80
.33
.43
.32
.59
.74
.81
.25
.79
.01
.96
.11
.66
.06
.19
.61
.65
.90
32
48
68
71
87
2.12
4.29
,42
,03
,54
,49
.62
2.27
3.35
1.88
1.56
1.48
1.94
2.37
2.49
1.83
2.86
2.51
2.90
2.08
Treatment
System
SB-ASB-C
C-A
C-TF-C
SB-SB-SB
SB-ASB
C-ASB
C-ASB-PS
C-ASB-PS
C-ASB-PS
C-A
C-ASB-PS
C-ASB
C-ASB-C
C-ASB-PS
C-TF-C
C-ASB
C-ASB
C-ASB
C-A
C-PS
FL
C
C
FL
"Ratio of Maximum day to annual average values
423
-------
Table 105
Variability Factors
Bleached Kraft Soda, Groundwood, Sulfite, Deink,
NI Fine Papers, and NI Tissue (fwp) Subcategories
Parameter Maximum 30 Days Maximum Day
BOD5_ 1.78 3.42
TSS 1.82 3.38
NI Tissue Papers Subcategory
Parameter Maximum 30 Days Maximum Day
BOD5_ 1.79 3.25
TSS 1.76 3.60
424
-------
greater than half the bleached kraft data sets (without
documented treatment system failures).
Non-Continuous Dischargers: Effluent Variability Ratios
In order to determine the average of 30 consecutive days and
maximum day effluent limitations in terms of concentrations
for non-continuous dischargers, variability factors were
determined through a data analysis using final effluent BOD^
and TSS concentration data, which were similar to the
analyses discussed above which used kg (Ibs) of BODS^ or TSS
as a basis. Since the analyses were similar, the
appropriate Tables and Figures are presented in this section
but the analyses will not be further discussed. Table 106
presents variability factors for non-continuous dischargers,
Tables 107 and 108 present the final effluent data used as
the basis for the variability factors, and Figures 81, 82,
83 and 8U graphically display the effluent variability data.
Unit Processes Used In Cost Development
In order to develop the estimates of costs presented in
Section VIII, it was necessary to develop external treatment
trains for the various subcategories. The following is a
description of the unit processes which make-up the
treatment trains.
Preliminary Treatment
Many foreign objects enter mill sewers, either through mill
floor drains or process sewers. These objects, such as wood
chips, bark, wet strength paper, etc., could interfere with
the treatment processes or increase wear on the process
equipment. Consequently, it is necessary that these objects
be removed from the mill sewers prior to treatment. A
mechanically cleaned bar screen is generally used by most
pulp and paper mills for preliminary treatment. The high
solids mill sewers flow into this facility, with the low
solids sewers bypassing it. The bar screen used is a
mechanically operated, self-cleaning travelling bar screen
with a bar spacing of 1-2 inches. A bypass channel and
manual bar screen are incorporated into the facility to
allow for screening during periods of maintenance on the
mechanical bar screen. A "dumpster" unit is used for
containment of the removed solids.
It is advantageous to monitor and sample the flow to the
treatment process. Therefore, the preliminary treatment
facility includes the necessary flumes and monitoring and
sampling equipment for complete flow measurement and
425
-------
TABLE 106
VARIABILITY FACTORS FOR
NON-CONTINUOUS DISCHARGERS
Parameter Maximum 30 Days Maximum Day
1.86 3.25
TSS 1.80 3.50
426
-------
TABLE
107
NON-COWTINUCUS DISCHARGERS
FINAL EFFLUENT OONCEOTRATION VARIABILITY
Mill
Annual
Average
gA
BOD5
Ratio of
Maximum Day
to An.Av.
TSS
Ratio of
Maximum Day
to An. Av.
001
001A
001B
002
002A
003
004
004A
005
006
007
008
041B
051
052
053
100
100B
101
101A
101B
103
10 3B
104
105
106
107
10 7A
107B
108
109
110
110A
11 IB
112
113
113A
114
114A
116
116B
117
117A
118
119
120
121
122
125
127B
134A
149B
150
161B
203
204
205
20 5B
206
257A
270B
279B
308B
318B
330B
333B
401B
22
11
11
27
37
77
34
35
24
58
53
149
41
60
96
29
90
58
8
10
11
65
33
30
16
28
17
21
21
38
38
32
36
18
12
33
36
34
18
67
60
11
14
53
11
27
28
53
29
?Q
20
82
18
225
44
197
112
93
63
31
81
51
8
47
19
120
44
06
88
64
64
36
83
54
52
2.85
2.20
2.19
1.61
5.18
2.01
1.63
2.65
3.87
07
76
73
29
63
69
64
09
32
56
58
3.21
66
83
15
99
24
22
25
56
65
06
69
80
10
2.15
67
54
15
18
2.38
2.53
55
07
96
93
49
43
15
36
48
39
27
18
39
80
94
26
1.85
33
28
74
75
71
18
18
23
46
21
10
52
12
15
15
28
23
56
28
87
73
75
67
43
16
23
313
256
34
106
41
47
54
IS
37
261
27
51
47
110
49
29
56
21
53
37
71
2.66
3.10
5.87
6.19
2.65
.40
.62
4.
2.
2.35
2.99
93
70
18
51
55
05
3.79
86
53
2.78
3.21
2.51
3.67
2.71
2.60
3.04
3.47
1.88
1.81
3.44
3.37
2.38
2.96
2.35
4.66
3.27
1.87
7.70
3.00
2.98
2.60
79
93
64
84
02
05
2.40
427
-------
TABLE 108
NON^DNTINUOUS DISCHARGERS
FINAL EFFLUENT CONCENTRATION VARIABILITY
BOD5
TSS
Mill
1
1A
2
2A
3
4
5
6
51
52
53
100
101
101A
103
104
105
106
107
107A
108
109
110
110A
112
113
113A
114
114A
116
117
117A
118
119
120
121
122
125
127A
134A
152
204
Annual
Average
tng/L
22
11
27
39
77
34
24
58
60
96
29
90
8
10
65
30
16
28
17
21
38
38
32
36
12
33
36
34
18
67
11
14
53
11
27
28
29
29
82
112
Ratio of
Max, 30 days
to An.Av.
1.57
2.30
2.47
2.33
1.42
1.25
2.27
1.73
1.43
1.24
1.86
2.30
2.03
1.50
2.78
1.68
1.53
2.82
1.51
1.78
1.46
1.39
1.55
1.52
1.06
2.60
2.06
2.40
2.01
1.15
1.
1,
1,
1,
1,
86
62
68
61
51
1.61
2.02
1.75
1.49
1.52
Annual
Average
mg/1
33
74
75
71
18
23
53
46
21
10
12
15
28
56
28
87
75
67
34
23
313
34
106
41
47
54
35
261
217
Ratio of
Max. 30 days
to An .Ay.
1.75
2,
2.
1,
2,
1,
1.
53
68
55
07
78
66
1.96
1.34
1.93
1.16
1.78
1.59
1.78
2.06
2.19
2.26
1.80
2.40
2.34
1.26
,39
.02
,03
.27
,57
,46
.21
1.56
428
-------
•£»
rxj
FIGURE 81
NON-CONTINUOUS DISCHARGERS
FINAL EFFHJENT CXJCBNTRATTON VARIABILITY
BODs: Maximum Day
a - Process and Treatment
changes (Mill 001}
b - Sampling and Amnroniator
problems (Mill 002)
c - Aerator failures (Mill 113)
d - Aerator failures (Mill 106)
e - Clarifier Outage (Mill 114)
0 10
20
30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200
Annual Average BODs (mg/1)
-------
OJ
o
§. 3.0
a
>,2.9
-3
o 2.6J
m
| 2.4-
-3 2.2
-u
* 2.0.
3 1-8
| 1-6
1.4
1.2
1.0
FIGURE 82
NON-CONTINUOUS DISCHARGERS
FINAL EFFLUENT CONCENTRATION VARIABILITY
BODs Maximum 30 days
a - Process and treatment
changes (Mill 001)
b - Aerators shut down to
conserve energy (Mill 125)
c - Sampling and ammoniator
problems (Mill 002)
d - Aerator failures (Mill 113)
e - Aerator failures (Mill 106)
f - Clarifier ontage (Mill 114)
186 mg/1 variability ratio
ID 20 30 40 50
60 708090 100 110 120 130 140 150 160 170 180 190 200
Annual Average BODs (mg/1)
-------
a
8.0
7.0
6.0
£ ^ 5.0
ir
•H
i-l
•t-l
"§ 3.0
2.0-
10
FIGURE 83
NON-CONTINUOUS DISCHARGERS
FINAL EFFLUENT ONCENTROTION VARIABILITY
TSS: Maximum Day
a - Inadequate treatment (Mill 100)
b - Sampling and anmoniator
problems (Mill 0023
c - Operating procedures (Mill 127)
350 nq/1variability ratio
0 IB 30 35 40 50 55 70 80 S'6 100 110 120 130 145 150 160 170 180 190 200
Annual Average TSS (rag/1)
-------
T
%
Ǥ
B
&
•8
o
ro
X
I
-H
4J
2
-H
r-4
•H
•8
1
3.0.
2.8
2.6
2,1
. H
2.2
2.0
1.8.
1.6
1.4
1.2
1.0
FIGURE 84
NON-CONTINUOUS DISCHARGERS
FINAL EFFLUENT CONCENTRATION VARIABILITY
TSS: Maximum 30 days
a - Inadequate treatment
.1 system (Mill 100)
* b - Inadequate treatment
^ system (Mill 4)
c - Aerator failures (Mill
^c A* d - sanpling and aimxaniator
A problems (Mill 002)
T ± e - Aerator failures (Mill
L / f - Clarifier outage (Mill
A /
A°- /
i
l\ * A * ~ 180 mg/1 variability ratio
A 1 A A
A
A
A
4
A
106)
113)
114)
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200
Annual Average TSS (irg/1)
-------
sampling. The capital costs prepared for the preliminary
treatment facility include the necessary excavations, back
fill, concrete, mechanical equipment, flow monitoring
equipment (with necessary ancillary equipment), and the
superstructure.
Mill Effluent Pumping
Normally, the topography of the effluent treatment site is
not conducive to gravity flow through the entire treatment
process. Consequently, it is necessary to construct an
effluent pumping facility which is capable of pumping the
maximum daily flow of the treatment facility. The pumping
facility used includes a wet well and dry well. The mill
effluent flows into the wet well (with detention time of
five minutes at maximum daily flow), while the variable
speed pumps are located in a dry well adjacent to the wet
well. The construction costs prepared for the mill effluent
pumping facility include excavation, backfill, concrete,
pumps, variable speed controls, ancillary piping and
equipment, and superstructure.
Primary Clarification
Sizing of primary clarification equipment used in the
development of costs is based on internal fiber recovery
being accomplished to the degree of economic justification.
Therefore, external fiber recovery for reuse has not been
considered in the treatment process design. All mill sewers
containing suspended solids are combined prior to primary
clarification, with total removal being accomplished by
mechanical clarification. For purposes of determining the
amount of sludge produced, reductions by primary
clarification of 75 to 85 percent of total suspended solids
were used. The clarifier selected for this report is a
heavy-duty thickener type with rotary sludge scraper, and
scum removal facilities. The size of these units are based
on an average design overflow rate of 600 gpd/ft 2. The
rotary sludge scraper mechanism is sized for a torque rating
of 15 (D) 2. For flows in excess of five (5) mgd, two
parallel units, each capable of 50 percent of the daily
flow, were used. Waste solids are withdrawn by pumping from
the primary clarifier at an anticipated solids content of 3-
4 percent to either a sludge lagoon or a mechanical
dewatering device. Scum collected in the clarifier
discharges into a storage tank where it is then pumped for
dewatering. The capital costs prepared for primary
clarification include excavation, backfill, concrete,
mechanical, electrical, and instrumentation equipment, scum
433
-------
facilities, waste sludge pumps, and yard piping related to
unit construction.
Sludge Lagoon
Waste solids pumped from the mechanical clarifier can be
dewatered in a lagoon. In a sludge lagoon the waste solids
are allowed to settle, the decanted water recycled back to
the waste treatment system. In addition, a sludge lagoon
may serve as an emergency solids disposal area when the
mechanical dewatering facilities are down due to mechanical
malfunction. The lagoon costed in this report provides
sufficient capacity for five years' detention of 20 percent
solids. The capital cost includes the required earthwork to
construct such a facility.
Aeration
BOD5_ reduction in pulp and paper wastes is generally
accomplished by biological treatment. Oxygen required for
biological treatment may be supplied either by mechanical
surface aerators or a diffused air system. The costs
presented in this report are based on the use of mechanical
surface aerators. The aeration equipment is sized to
provide sufficient oxygen for BOD5_ reduction and to ensure
proper mixing. Depending on the particular biological
treatment process selected, oxygenation requirements will
differ.
One of the most used biological treatment processes by the
pulp and paper industry is the Aerated Stabilization Basin
(ASB). Standard design criteria for aeration of an ASB
system suggests providing approximately 1.25 Ibs 02/lbs
BOD5_. For this report, it was assumed that the efficiency
of the mechanical aerators under actual operating conditions
is approximately 1.75 Ibs 02/hp-hr. This varies depending
on type of equipment and the characteristics of the system
(temperature, basin configuration, biological
characteristics, alpha and beta).
The activated sludge system with its many process variations
has had limited use by the pulp and paper industry. For
cost analysis in this report, a high rate activated sludge
system was considered. This system requires approximately
one pound of oxygen per pound of BODJ5 removed. Mechanical
aerator performance for this system is assumed to be the
same as that listed above for an ASB.
434
-------
Aerated Stabilization Basin
Biological treatment by aerated stabilization basins has
received wide acceptance by the pulp and paper industry.
Aerated Stabilization Basins provide a high degree of BODj>
reduction with minimal decreases in efficiencies due to
shock loadings. In general, however, pulp and paper wastes
are deficient in the nutrients (nitrogen and phosphorus)
required for optimum biological treatment. Consequently, it
is necessary to add these nutrients, usually in the form of
ammonia and phosphoric acid, to the biological treatment
system. The nutrients are added in proportion to the
organic (BOD5) loading of the facility. The ratio used for
the cost analysis is 100:5:1, BOD5:N:P.
The basins chosen for preparation of the cost curves is a
single cell earthen-construction basin. In most instances
the basins are constructed in areas where the soils are
impervious, or can be made impervious by lining with an
impervious soil. For cost purposes it is assumed that an
impervious soil liner will be required to make the basin
watertight. The cost of a synthetic liner is not included.
The sizing of the aerated stabilization basins were
evaluated on both organic loading rate and detention time
design criteria. The design detention time is 14 days,
which assumed 13 days of aeration with one day of quiescent
settling. The design organic loading is 50* BODj>/Ac-
ft./Day. The basin sizes obtained for the above cited
detention time and organic loading were compared to
determine which criteria was the governing value.
The capital costs prepared for the aerated stabilization
basin include excavation, dike construction, impervious soil
material, nutrient feed systems, yard piping, stone slope
protection and the instrumentation and electrical costs
associated with the basin size.
Activated Sludge Basin
The activated sludge process has numerous modifications in
detention times, organic loadings, and oxygenation. The
process selected for consideration in this report is
commonly referred to as the conventional activated sludge
process (6 to 8 hours detention time). The short detention
time and variations in loadings (hydraulically and
organically) make this process susceptible to upsets due to
shock loadings. It is recommended that an equalization
basin be included with this system to even out hydraulic and
organic loads to the system.
435
-------
As stated previously, pulp and paper wastes are deficient in
nutrients (nitrogen and phosphorus). The nutrients are
added in proportion to the organic (BODjj) loading to the
facility. A BOD5_:N:P ratio of 100:5:1 is used for cost
analysis in this report.
Final clarifiers are required with the activated sludge
basin to allow separation of the biological mass and treated
stream. A large portion of these solids are recycled back
to the activated sludge basin to maintain the biological
mass in the aeration basin. this biological mass is
necessary to achieve high removal efficiencies. The high
rate activated sludge system also generates large quantities
of biological solids which are not oxidized as in ASB
systems. It is necessary, therefore, to continuously remove
excess biological solids. These excess solids (waste
activated sludge) can be extremely gelatinous with a solids
concentration of approximately 0.5-1.0 percent. A
discussion of the methods for disposal of these excess
solids is presented in Section VIII.
Since the activated sludge process has high horsepower
requirements, an earthen basin would be susceptible to
erosion. Consequently, the costs prepared for the activated
sludge basin are based on a two-cell concrete tank. The
cells would be operated in parallel to provide operational
flexibility. The clarifiers associated with the activated
sludge process are described in a subsequent process item.
As in the ASB system, sizing of the activated sludge system
is based on both detention time and organic loading. The
detention time is eight hours (excluding recycle) while the
organic loading rate is 50 Ibs BOD5/1000 Cu. Ft. of
aeration volume. The governing value was selected for cost
analysis in this report.
The capital costs prepared for the activated sludge basins
(presented as a function of the basin capacity) includes
excavation, tank construction, concrete, nutrient feed
systems, yard piping, electrical and instrumentation costs
associated with the basin size.
Equalization Basin
An equalization basin is required quite often to minimize
upsets due to fluctuation in pH valuations, and hydraulic
and organic variations. This is particularly true of the
activated sludge process. The equalization basin utilized
for cost analysis provides a 12-hour detention time for
equalization of process upsets and hydraulic peaks. The
436
-------
basin utilized is a concrete tank with control facilities to
equalize the flow. The capital costs include excavation,
tanks construction, concrete, backfill, and yard piping.
Vacuum Filtration
Various unit process are used by the pulp and paper industry
for sludge dewatering (both primary and secondary solids).
The method which has gained the widest acceptance in the
industry is vacuum filtration. A vacuum filter consists of
a rotary drum covered with a wire mesh on coil springs which
is partially submerged in the waste solids. The rotary drum
is divided into a series of compartments which are placed
under a vacuum when submerged in the waste solids. The drum
rotates so that when a compartment reaches the top of the
circle the vacuum is released. A filter cake is built up on
the filter media, and as it descends in rotation, this
filter cake is removed from the filter media prior to re-
submergence in the waste solids. The efficiency of vacuum
filtration operation is greatly affected by the consistency
and properties of the waste solids being dewatered. The
dewatering operation is more efficient and economical when
the waste sludge solids to the filter are in a range of 3 to
5 percent. Consequently, often times it is advantageous to
prethicken the waste sludge solids prior to vacuum
filtration. This is particularly true when dewatering waste
solids from a biological system.
The waste sludge (primary, excess biological solids, and
solids from an ASB clari-flocculator) obtained from each
treatment process is unique. The sludge obtained from each
process requires detailed analyzation prior to actual design
of dewatering facilities.
Waste sludge obtained from primary clarification usually has
a solids content of 3 to 5 percent. These sludges normally
contain fibrous material and wood particles which enhance
its filterability. A filter rate of 6f Dry Solids/ sq.ft.
Filter Area/Hour is normally used for dewatering of primary
waste solids. This filter loading rate for primary solids
can often times be achieved without the addition of
chemicals; however, occasionally chemicals are required to
obtain a filter cake of 20 to 30 percent solids.
As described previously, the waste biological solids
obtained from an activated sludge system can be extremely
gelatinous. This type of sludge is quite difficult to
dewater because of its consistency and requires thickening
prior to vacuum filtration. Once thickened, the waste
biological solids can be combined with primary waste solids
437
-------
for vacuum filtration. When thickened waste biological
solids are combined with primary solids, filter rates of
4#/Sq.Ft./Hour are normally obtained with the addition of
chemicals to aid the vacuum filtration process. Solids
removal by clarification following an ASB is not a common
practice in the pulp and paper industry. However, as solids
removal becomes more important, industry will require such
facilities. The solids in the effluent of an ASB are
difficult to settle and dewater. Consequently, it is
anticipated that a flocculant (such as alum) might be added
at dosage rates of 100 to 300 mg/1 in order to obtain
efficient solids removal.
The capital costs prepared for vacuum filtration of waste
solids include: solids storage tank and pumping, building,
mechanical equipment and appropriate ancillary equipment,
process piping, electrical, instrumentation, and a standby
vacuum filter unit. The operation and maintenance costs
include disposal of the solids to a landfill site.
Sludge Press
Many times it is advantageous to provide additional solids
dewatering after vacuum filtration prior to ultimate
disposal, particularly if the solids are to be burned. This
is normally achieved by use of a V-Press. A V-Press will
normally raise the solids concentration to 35 to 40 percent
solids. A screw conveyor feeds solids into a gap between
two revolving press wheels. These wheels carry the solids
around till a so-called "pinch point" is reached. At this
point the maximum pressure is exerted on the solids. The
pressed solids are then released as the wheels gradually
diverge. A screw conveyor then discharges the solids into a
receiving container. The filtrate from the pressing
operation is then recycled back to the treatment system.
The capital costs for pressing of waste solids following
vacuum filtration include mechanical equipment and ancillary
equipment, electrical and instrumentation, and building.
Flotation Thickening
As cited previously, waste biological and/or biological-
chemical solids from the secondary clarification process
require thickening before they can be efficiently dewatered.
If these solids are not thickened prior to vacuum
filtration, the capacity of the vacuum filter is greatly
reduced. Air flotation was selected as the thickening
process used for the development of costs. Air flotation
requires addition of a flocculant such as a polymer to
assist in the thickening process. The polymer is added to
438
-------
tne waste solids prior to introduction into the flotation
unit.
Air flotation requires the diffusion of air into the waste
solids. This may be accomplished by a so-called
"pressurization system". Basically, three types of
pressurization systems are available-total, partial, and
recycle pressurization. In a total pressurization system,
the entire waste solids stream is pressured in an air
saturation tank. The partial pressurization system
withdraws a portion of the influent waste solids flow to be
pressurized and saturated with air. This pressurized flow
is then discharged back to the influent line. In recycle
pressurization, a portion of the effluent from the flotation
unit is pressurized and saturated with air and recycled back
to the influent.
The pressurized influent enters the flotation unit where the
diffused air bubbles are allowed to surface. Diffusion of
the air bubbles promotes coagulation and ultimate thickening
of the waste solids. The coagulated solids (thickened
sludge) are then removed for vacuum filtration. It is
anticipated that air flotation will increase the secondary
waste solids to 3 to 4 percent solids. The filtrate and
scum from the air flotation is recycled back to the
treatment process. As in vacuum filtration, there are
numerous process variables that can be evaluated in sizing
air flotation units. For this study it was assumed that the
hours of operation of the flotation thickening equipment
would vary depending on the solids loading. The following
hours of application v/ere assumed:
Secondary Solids - ft/Day Hours/Week
0-5,000 42
5,000-20,000 84
20,000-60,000 126
An air flotation loading rate of 2# Dry Solids/Sq.Ft./Hour
was used in design of these facilities. The capital costs
for air flotation thickening of waste biological and
biological-chemical solids include building process
equipment, chemical feed system, electrical,
instrumentation, and ancillary equipment.
439
-------
Secondary Clarification
Secondary clarification is required with an activated sludge
system to provide separation of the biological mass and
treated stream. In addition, they are often required after
an ASB system for supplemental solids removal. The
clarifier most effective for secondary solids separation is
the contact type. The effluent from the activated sludge
basin or ASB system flows into a flocculation chamber in the
clarifier. In this chamber flocculants such as alum and
polymer are added to the waste water stream. Low speed
mixers disperse the flocculants throughout the chamber
allowing for coagulation and floe formation. The waste
water stream then flows into the clarifier area for solids
separation.
For flows in excess of five (5) mgd, two parallel units,
each capable of 50 percent of the daily flow, were assumed
to be used. The design overflow rate for the clarifiers,
excluding flocculation area, is 500 gpd/sq.ft. The drive
mechanism would be rated for a torque of 10 (D)2.
In an activated sludge system, most of the biological solids
settled in the secondary clarifiers are recycled to the
aeration basin to maintain an active biological mass in the
aeration basin. Pumping capacity is provided for a maximum
recycle rate of 75 percent of the average daily flow with an
average recycle rate of 40 percent of the average daily
flow.
The capital costs presented for secondary clarification
include excavation, backfill, concrete, recycle pumps,
mechanical equipment, electrical, instrumentation, yard
piping, and ancillary equipment for proper operations.
Neutralization
Pulping processes significantly change the pH of a waste
water. Such variations in pH can affect the waste treatment
process; therefore, it is necessary to add chemicals (acid
and/or caustic) and flash mix the waste water for
neutralization.
The capital cost for pK adjustment includes excavation,
backfill, concrete, mixer, chemical feed system, etc. The
flash mix tank provides one minute detention time at peak
flow with a mixer sized at 1 Hp/1000 gal. capacity of mix
tank.
440
-------
Flow Monitoring Structure
In order to monitor the unit processes and overall
efficiency of the treatment process, it requires
installation of flow monitoring structures throughout the
process. The flow monitoring structure considered in this
study includes a Parshall flume and automatic sampling
equipment.
Foam Control
In many installations, foam control is very critical.
Included in this study, as required, is a foam tank with
adequate capacity for storage of foam. As the foam builds
up in the facility, it eventually settles because of its
inability to support its own weight. The foam tank provides
for a five-minute hydrqulic capacity.
Outfall Sewer
The outfall sewer is defined as the sewers required to
connect the mill to the treatment facility and the treatment
facility to the diffuser. Thus, for this cost analysis, one
(1) mile of outfall sewer is assumed to be required to make
these connections.
Diffuser
Discharge from the outfall sewer is assumed to be through a
multiple-port diffuser which will facilitate mixing of the
treatment facility effluent with the receiving water. Such
induced mixing will minimize any horizontal and vertical
stratification of the effluent in the receiving waters. The
costs presented in this report assume that the diffuser is
of standard design and that moderate underwater conditions
will be encountered. Standard design recommends 10 to 15
feet of diffuser/mgd; therefore, 12 feet/mgd was used. This
can vary substantially depending on the desired and required
diffusion characteristics. The capital costs include
excavation backfill, laying and jointing of the diffuser
pipe.
Summary
A summary of the design criteria discussed above is
presented on Table 109. Schematic flow diagrams of the
alternative treatment trains which are the basis for the
Section VIII cost estimates are shown on Figures 85, 86 and
87.
441
-------
TABLE 109
Design Criteria
for
Cost Analysis
Hydraulic
Peak flow rate = 2X Annual Average
Mill Effluent Pumping
Pump station with 2-4 variable speed pumps. The number of pumps
varies with facility capacity.
The pumps located in a pit adjacent to the wetwell.
Primary Clarification
Number of Units: 2 for flows in excess of 5 MGD
Overflow Rate: 600 gpd/ft.2 (Q design)
Side Water Depth: 12 feet
Torque: 15 (D)2_
Neutralization
Number of Units: 1
Detention Time: 1 in in. at peak daily flow
Mixer: 1 HP/1,000 gal.
Sludge Lagoon
Detention Time: 5 years at 20% solids
Primary SoJ.ids Dewatering
Vacuum Filter
///D Hours Operation/Week
20,000-50,000 84 hours
50,000- 126 hours
Loading Rate: 6 #/S.F./Hr.
Number of Units include 1 standby
Aerated Stab_i_liza^ion Basin
Number of Basins: 1
Loading Rate:
Biological - 50 //BOD/AC-FT/DAY
Detention - 14 days, 13 days Aeration; 1 day Settling
Aeration Required:
1.75 //02/HP-HR
1.25 //02///BODR
442
-------
TABLE 109 (Cont.)
Side Water Depth: 12 feet
Nutrient Feed System:
Feed Capacity: 100:5:1
Activated Sludge Basin
Number of Basins: 2
Loading Rate:
Biological - 50 //BOD/1000 FTJ3
Detention Time - 8 hours
Aeration Required:
1.0 //02///BODR
Side Water Depth: 12 feet
Nutrient Feed System:
Feed capacity: 100:5:1
Secondary Clarification
Number of Units: 2 for flows in excess of 5 MGD
Type: Solids Contact Type
Overflow Rate: 500 gpd/Ft2.
Side Water Depth: 12 feet
Torque: 10(0)2^
Recycle Pumps
Pump Capacity: 25-75% (Q Avg.)
Head: 40 feet TDH 70% efficiency
Average Capacity: 40% (Q Avg.)
Solids Dewatering (Primary and Secondary)
Vacuum Filtration:
Hours Operation: Same as Primary Dewatering
Loading Rate:
Without Wood Fines - 4 ///SF/HR
Number of Units including 1 standby
Flotation Thickening
Hours of Operation:
tf/D HRS/WEEK
0-5,000 42
5,000-20,000 84
20,000-60,000 126
Loading Rate: 2///SF/HR
Foam Tank
Detention time: 5 minutes
Freeboard: Maintain 12 feet for foam buildup
443
-------
FIGURE 85
SCHEMATIC FLOW DIAGRAM
ACTIVATED SLUDGE ALTERNATIVE
BPCTCA EFFLUENT TREATMENT TECHNOLOGY
-------
-"\ -^-
\
FIGURE 86
SCHEMATIC FLOW DIAGRAM
AERATED STABILIZATION BASIN ALTERNATIVE
BPCTCA EFFLUENT TREATMENT TECHNOLOGY
-------
FIGURE 87
SCHEMATIC FLOW DIAGRAM
NON INTEGRATED TISSUE
BPCTCA EFFLUENT TREATMENT TECHNOLOGY
-------
SECTION VIII
COSTS, ENERGY, 6 NON-WATER QUALITY ASPECTS
In establishing effluent limitations, the costs, energy, and
the non-water quality aspects of the technology suggested
for compliance with the effluent limitations have been
assessed. Previous sections have discussed many of the
internal control technologies and the external treatment
technologies available for compliance with the effluent
limitations. This section summarizes the costs, energy, and
non-water quality impact of the suggested control and
treatment technologies for compliance with the effluent
limitations. The non-water quality aspects to be addressed
are:
1. Air pollution
2. Noise Pollution
3. Solid waste
4. By-product recovery
5. Implementation
DEVELOPMENT OF COSTS
Compliance with the effluent limitations requires
implementation of internal controls and effluent treatment.
Based on the extensive data analysis efforts, raw waste
water and final effluent characteristics were established
for each subcategory, using the installed technology. The
waste water characteristics used for cost analysis are
presented in Table 110.
As mentioned previously, capital and operating costs have
been determined for implementation of the technology to
comply with the effluent limitations. Based on anticipated
capital and operating expenditures, an economic analysis has
been completed to determine the economic impact of the
limitations. The economic analysis addressed such areas as:
(1) price effects, (2) closure and production effects, (3)
short-term capacity constraints, and (4) balance of trade.
The segment of the pulp, paper, and paperboard point source
category included in this study has been divided into 16
subcategories. These 16 subcategories include between 250
and 300 mills located throughout the United States in
various climates and site locations. The raw waste
characteristics and mill sizes vary. Detailed assessment of
the capital expenditures for implementation of the
limitations is difficult. Full assessment of costs for each
447
-------
TABLE no
BPCTCA
WASTE WATER CHARACTERISTICS
(Data in kgal/ton for Flow and ]b/ton for all others)
Groundwood Chemi-mechanical
Flow
BOD
TSS
Groundwood Thermo-niechanical
Flow
BOD
TSS
Groundwood Fine
Flow
BOD
TSS
Groundwood CMN
Flow
BOD
TSS
Bleached Kraft Dissolving
Flow
BOD
TSS
Bleached Kraft Market
Flow
BOD
TSS
Bleached Kraft BCT
Flow
BOD
TSS
Bleached Kraft Fine
Flow
BOO
TSS
Soda
Flow
BOD
TSS
Deink
Flow
BOD
TSS
Nonintegrated Fine
Flow
BOD
TSS
Nonintegrated Tissue
Flow
BOD
TSS
Nonintegrated Tissue (FWP)
Flow
BOD
TSS
Paper Grade Sulfite - Blow Pit
Flow
BOD
TSS
Paper Grade Sulfite - Vacuum Drum
Flow
BOD
TSS
Dissolving Sulfite - Nitration
Flow
BOD
TSS
Dissolving Sulfite - Acetate
Flow
BOD
TSS
Raw Waste
27.0
191.0
104.0
21.0
78.4
79.8
21.9
33.3
105.0
23.8
34.8
97.D
55.1
133.0
226.0
41.6
75.9
90.0
35.4
76.7
133.0
30.9
67.2
150.0
34.1
86.5
285.0
24.4
180.0
405.0
15.2
21,
61,
22.9
22.9
69.4
25.2
29.0
221.0
53.0
242.0
180.0
53.0
207.0
180.0
66.0
274.0
185.0
66.0
404.0
185.0
Final Effluent
7.9
11.5
4.9
9.0
4.0
6.9
4.4
7.5
13.8
22.1
9.0
17.6
8.0
16.2
6.2
13.1
8.0
K.5
10.6
14.2
4.8
6.6
7.0
5.7
7.2
10.4
20.8
30.9
19.0
30.9
29.7
41.8
448
-------
specific plant would require numerous treatability-pilot
plant studies, soil investigations, engineering designs,
etc.
The actual control and treatment technology costs vary at
each individual facility depending upon the design and
operation of the production facilities and local conditions,
and 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 represent those of the subcategories covered by this
report. However, the industry is somewhat heterogeneous in
that almost every installation has some uniqueness which
could be of importance in assessing effluent treatment
problems and their associated costs. Consequently, the cost
analyses performed to assess the overall industry costs were
determined by the "model" mill approach. "Pre-engineering"
cost estimates developed by the economic analysis are
considered to have a variability of plus or minus 20
percent. The model mill approach provides a representative
impact of the effluent limitations on industry as a whole.
For compliance with BPCTCA costs of both internal and
external technology were established for various sizes of
"model" mills in each subcategory in order to reflect the
significance of mill size upon the costs of implementing the
technology.
The number of "model" mill sizes and their production sizes
were selected from the size range of existing mills so that
the ratio of one size to the next approximated 3:1. The
selected mill sizes for each subcategory are shown in Table
111. It must be emphasized that utilization of "model"
facilities requires that numerous premises be made.
Discussion of these premises are presented later.
All costs presented in this Section except as noted are in
terms of June, 1974 dollars. Since construction costs
escalate, this may be adjusted by appropriate cost indices
to represent the time reference necessary. The most
accepted and used cost index in the engineering field is the
Engineering News Record (ENR) construction cost index. The
ENR index value of 1,995 used in this report was taken from
the "U.S. - 20 Cities Average" for June, 1974.
449
-------
TABLE 111
MODEL MILL SIZES
kkg/day (tons/day)
Subcategory
Sulfite Vacuum Drum
Sulfite Blowpit
Dissolving Sulfite
Deink
Dissolving Kraft
Market Kraft
BCT Kraft
Fine Kraft
Groundwood Chemi-Mech.
Groundwood Thermo-Mech.
Groundwood C-M-N
Groundwood Fine
Soda
Nonintegrated Fine
Nonintegrated Tissue
Nonintegrated Tissue (FWP)
Very
Small
14(15)
14(15)
Small
145(160)
145(160)
73(80)
227(250)
227(250)
91(100)
91(100)
68(75)
136(150)
27(30)
32(35)
32(35)
Medium
430(530)
480(530)
499(550)
209(230)
544(600)
318(350)
608(670)
608(670)
272(300)
272(300)
136(150)
272(300)
272(300)
91(100)
100(110)
100(110)
454(500)
907(1000)
635(700)
1179(1300)
1179(1300)
544(600)
544(600)
454(500)
497(550)
635(700)
254(280)
408(450)
408(450)
450
-------
Internal Control Technologies
As a result of past and recent reconnaissance surveys an
analysis of internal control technologies was completed.
Discussions in Section VII presented the control
technologies identified for compliance with BPCTCA. The
development of cost data for the internal control technology
originated from such flow schematics as presented
previously. A model facility was then selected for basing
equipment layouts, including pumps, piping, valving, tanks,
controls, etc. Table 112 presents the number of paper
machines used, where appropriate, as a basis for internal
control cost development.
Capital costs were then prepared for the various
technologies. Various sources such as Process Plant
Construction Estimating and Engineering Standards, equipment
manufacturer quotations, and contractor prices for similar
work were used in estimating the costs. Miscellaneous
materials and installation labor were included in the
installed costs. All costs were quoted or adjusted to June
1974 dollars. Factors such as freight, engineering and
contingencies are included in the total capital control
technology costs.
The costs developed for the "model" internal mill were then
factored for mills and subcategories of different size or
type from that used for the base estimate. The exponent-
based technique of estimating was utilized in adjusting the
costs. The appropriate exponent factors were used on this
type of equipment or construction. Such methodology
provides a reliable technique for preliminary evaluations
such as those required for an overall industry assessment
Each internal control as applied to a subcategory was
reviewed for net variable cost or savings by subtracting
maintenance and operating (materials, power, chemicals,
labor) from savings in power, fiber, heat and chemicals.
Previous cost analyses had assumed that savings were
adequate to cover operating and maintenance costs. However,
cases were found where this was not the case and net
variable (operating and maintenance) costs have been
included in the summary tables. Where a net savings
occurred, the operating and maintenance costs have been
shown as zero in order to be conservative.
451
-------
TABLE 112
NUMBER OF PAPER MACHINES
MODEL MILLS
Sulfite - Vacuum Drum
Sulfite - Blow Pit
Dissolving Sulfite
Deink
Dissolving Kraft
Market Kraft
BCT Kraft
Fine Kraft
Groundwood Chemi-Mech.
Groundwood Thermo-Mech.
Groundwood C-M-N
Groundwood Fine
Soda
Nonintegrated Fine
Nonintegrated Tissue
Nonintegrated Tissue (FWP)
3
3
2
2
2 Tissue
1 Board
5
2
2
2
2
2
3
3
3 Tissue
2 Board
5
3
3
2
3
2
2
3
3
4
3
9
4
4
3
5
5
5
5
5
Tissue
Board
452
-------
External Treatment Technology
As part of the data analysis efforts design criteria and
operating procedures were reviewed so that representative
design criteria and standard operating procedures could be
established for the cost analysis. The design criteria and
the technologies representing BPCTCA were discussed in
Section VII. In order to estimate the costs for
implementation of these design criteria and technologies it
was necessary to develop a model facility. These "model"
facilities are based on unit processes, yard piping layouts,
methods and materials of construction, site and soils
characteristics, unit construction costs, and operational
procedures.
The treatment technology items were then sized for the
design criteria discussed at various design flows chosen for
estimating. Quantity estimates were prepared for large
equipment and material items such as tanks, basins, yard
piping, etc. Several manufacturers were contacted to obtain
quotations for major pieces of process equipment. A
percentage of the equipment price was added to the equipment
cost for installation and startup of the equipment.
The construction costs for these facilities are those
defined as the capital expenditures required to implement
the treatment technology. Included in these costs are the
traditional expenditures for such items as mechanical and
electrical equipment, instrumentation, yard and process
piping, earthwork, unit construction, site preparation and
grading, equipment installation and testing, and
engineering.
The sum of both the quantity estimates and process equipment
estimates comprise the base capital cost. For estimates of
this nature, it is not feasible to obtain detailed estimates
for items such as electrical, instrumentation, process
piping, and site preparation. Therefore, these items are
included in the capital construction costs as a percentage
of the base capital cost. These percentages vary for the
different, control technologies. A contingency of 15 percent
of the base capital cost is included in each control
technology to cover miscellaneous work items that cannot be
accounted for in estimates of this nature. The sum of the
base capital cost and the applicable percentages comprise
the basic cost of construction.
453
-------
The annual operating costs are those associated with proper
and continued operation of the facility. These flow
variable costs are subdivided as follows:
1. Operational labor
2. Maintenance labor
3. Energy Requirements
4. Chemicals
Operator labor costs are based on the annual manhours
required to perform the tasks for proper operation,
administration, quality control, monitoring, etc., for the
"model" treatment facility. The maintenance costs are the
annual manhours required for preventative maintenance tasks
such as lubrication, equipment inspection, minor parts
replacement, painting, etc. Major equipment repair and/or
replacement and miscellaneous yard work is considered to be
done by the existing mill personnel. The costs estimated,
therefore, do not include major equipment repair or
replacement. Depreciation accounting, includes costs for
writeoff or replacement of the equipment.
The number of operational manhours for each control
technology was determined on the basis that the available
manpower is 80 percent efficient. In addition, 15 percent
of the annual manhours for operation and maintenance was
added for general supervision of personnel and public
relations.
An assessment of the energy requirements to implement each
treatment technology presented in this report are based upon
anticipated horsepower demands and operational time. The
basis for the external energy requirements is that process
equipment, excluding pumps and aerators, would require
approximately 75 percent of the installed available
horsepower for that equipment.
Wastewaters generated by the pulp & paper industry are
generally deficient in nutrients which are necessary for
optimum biological treatment efficiencies. Consequently,
nitrogen and phosphorous compounds are often times needed to
supplement those naturally present in the waste water.
Ammonia and phosphoric acid are the nutrient supplements
used in the cost analysis.
Chemicals are normally required to optimize the solids
dewatering processes. The chemical costs developed are
based on anticipated quantities required to optimize
operation of the particular solids dewatering technology.
454
-------
Once these capital operating costs were estimated for the
treatment technologies, cost curves were developed for each
treatment technology. These cost curves related standard
design parameter (flow, BOD, TSS, etc.) to a capital or
operation expenditure. Based on the raw waste and final
effluent characteristics developed through the data
analysis, costs were developed for the specific "model"
mills. The methodology utilized allows for variations in
peak flows, quantity of solids generated, BOD loading, etc.
Annual Fixed Charges
The annual fixed charges are those operating costs which are
directly related to the capital expenditure for construction
of the pollution abatement facilities. These charges
commonly include such items as depreciation on the control
technology and the interest on the capital borrowed for
construction. In addition, such costs as maintenance
materials, spare parts, insurance and taxes are often times
considered part of the annual fixed charges.
The useful life of each structure and mechanical unit varies
depending on the physical wear or duty of it. Such pieces
of mechanical equipment which experience high service wear
may have a useful life of 5-10 years as compared with a
structure such as a building etc. which will have a useful
life of 40-50 years. Depreciation costs are those
accounting charges for the eventual replacement of a given
asset (equipment or structure) at the end of its useful
life.
Depreciation of the capital assets may be by accumulation of
digits (rapid depreciation) or method of averages (straight-
line) . Recent tax regulations allow for the rapid
depreciation (60 month) of capital assets for pollution
abatement. Review of data from private communications
indicates that this is not a widely used method. In
general, firms depreciate over a longer period of about 16
years. This is confirmed by NCASI Special Report No. 75-02
which indicates rapid amortization of only $7.8 million of
$424.6 million capital expenditures for pollution abatement
(345). The average annual depreciation rate presented in
this report is 6.9 percent. Consequently, this results in a
reasonable depreciation charge of approximately 7.0 percent
per year. Weighted depreciation will vary depending on the
complexities of the system. A system with large quantities
of earthwork and structures may have a depreciation rate of
6 percent as compared to a system with complex mechanical
equipment having a useful life of 10-15 years (i.e. 8
percent).
455
-------
Interest are those annual charges for financing the capital
expenditures for construction of a facility. Such financing
may be through corporate bonds, conventional lending
markets, or by tax exempt-municipal revenue bonds.
Municipal revenue bonds have lower interest rates as
compared to corporate bonds.
Recently, municipal revenue bonds have been used to finance
industrial pollution abatement facilities. Triple A rated
state and local Government Bonds interest rates are
estimated to be 6-7 percent during the next year.
Fluctuations in the bond markets caused by financial
difficulties of major metropolitan areas are not likely to
affect the interest costs over the long term. Some mills
will be required to finance their facilities through either
corporate bonds or conventional lending markets. Such bonds
are likely to have interest rates of 9-10 percent.
Based on this it is reasonable to assume that the average
interest rate may be 8 percent with actual rates varying
from 6-10 percent. NCASI Special Report 7:5-02 states that
tax exempt bonds were used by 29 percent of the mills.
Those using these bonds had an interest rate averaging 6.5
percent. This is felt to substantiate the assumed average 8
percent interest rate.
Insurance and taxes are commonly included in the annual
fixed charges. The actual rate for these charges may vary
significantly dependent upon such items as mill location
insurance coverage and tax credits. Based on available data
from industry and government these charges may vary from 1.5
to 2.5 percent of the capital investment. However, in many
areas of the country, there are local property tax credits.
Consequently, use of insurance and local property taxes at 1
percent of the capital expenditure are felt to be
reasonable.
A mill normally maintains an inventory of spare parts for
the major equipment items. Such an inventory allows a mill
to minimize the "down" time of a technology item. In
addition, many maintenance supplies are necessary for proper
maintenance of the process equipment. These items were
considered to represent 0.5 percent of the investment.
For the purposes of calculating annual costs, an average
fixed charge of 16.5 percent of the capital expenditure was
used which includes all of the above items. It should be
noted that these charges may vary from 13 percent to as high
as 20.5 percent and the use of 16.5 percent is for
illustrative purposes. This is dependent upon several
456
-------
items, such as the complexities of the system installed,
financing availability, insurance coverage, property tax
credits, spare parts inventory, and maintenance materials.
Summary
The capital, operating, and annual fixed charges for the
internal and external technologies have been summarized in
this section. The costs presented herein have been
developed for the purpose of assessing the overall industry
expenditure for compliance with the promulgated effluent
limitations. Each production facility or waste treatment
facility has some uniqueness which may be of importance in
assessing the mill's effluent treatment program and the
associated cost of waste treatment.
The cost for land may vary from $500 per acre to $10,000 per
acre depending on the particular location of a facility.
The pulp and paper mills located through the United States
vary in location from densely populated areas to isolated
mills located several miles from neighboring communities.
Consequently, the costs associated with land acquisition may
vary significantly from mill to mill. Therefore, in
determining the costs of achieving the BPCTCA effluent
limitations, land acquisition has not been included.
The "model" mill approach has been used for assessing the
cost of implementing the treatment and control technology.
Tables 113-129 summarize the anticipated expenditure for
each of the "model" mills. The capital costs have been
developed as discussed above. The operation and maintenance
costs include operation and maintenance labor, energy
requirements, and chemicals. The annual fixed charges
include depreciation and interest, insurance, taxes, spare
parts, and miscellaneous maintenance materials. These items
are included as 16.5 percent of the investment costs and are
for illustrative purposes only. Total annual costs include
operation and maintenance and the annual fixed charges.
For each of the subcategories, except non-integrated tissue,
alternative costs are presented for two biological systems:
aerated stabilization system and activated sludge system.
457
-------
TABLE 113
DISSOLVING KRAFT SUBCATEGORY
BPCTCA Effluent Treatment Costs
(all costs in thousands of dollars)
Ol
oo
Mill Size: 600 TPD
Internal
External
Total
Mill Size: 1000 TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Aerated Stabilization Basin
Capital Ann. Fixed Oper. & Total
Cost Charges Maint. Ann. Cost
1,240 205 -- 205
14,680 2,425 1,435 3,860
15,920 2,630 1,435 4,065
1,725 285 — 285
20,515 3,385 1.960 5,345
22,240 3,670 1,960 5,630
Activated Sludge
Capital Ann. Fixed Oper. & Total
Cost Charges Maint. Ann. Cost
1,240 205 — 205
19,015 3,140 1,650 4,790
20,255 3,345 1,650 4,995
1,725 285 — 285
26,770 4,420 2,525 6,945
28,495 4,705 2,525 7,230
-------
TABLE 114
MARKET KRAFT SUBCATEGORY
BPCTCA Effluent Treatment Costs
(all costs in thousands of dollars;
Mill Size: 350 TPD
Internal
External
Total
Mill Size: 700 TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Aerated Stabilization Basin
Capital Ann. Fixed Oper. & Total
Cost Charges Maint . Ann. Cost
865 145 — 145
8,650 1,425 530 1,955
9,515 1,570 530 2,100
1,355 225 — 225
13,490 2,225 920 3,145
14,845 2,450 920 3,370
Activated Sludge
Capital Ann. Fixed Oper. £< Total
Cost Charges Maint. Ann. Cost
865 145 — 145
10,830 1,785 725 2,510
11,695 1,930 725 2,655
1,355 225 — 225
17,145 2,830 1,210 4,040
18,500 3,055 1,210 4,265
-------
TABLE 11 5
BCT KRAFT SUBCATEGORY
BPCTCA Effluent Treatment Costs
(all costs in thousands of dollars)
CTl
o
Mill Size: 250 TPD
Internal
External
Total
Mill Size: 670 TPD
Internal
External
Total
Mill Size: 1300 TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Capital
Cost
1,965
6', 275
8,240
4,020
11,330
15,350
6,555
17,390
23,945
Aerated Stabilization
Ann. Fixed Oper.
Charges Maint.
325
1,035 435
1,360 435
665
1,870 915
2,535 915
1,080
2,870 1,550
3,950 1,550
Basin
& Total
Ann. Cost
325
1,470
1,795
665
2,785
3,450
1,080
4,420
5,500
Capital
Cost
1,965
7,730
9,695
4,020
14,490
18,510
6,555
22,765
29,320
Activated
Ann. Fixed
Charges
325
1,275
1,600
665
2,390
3,055
1,080
3,755
4,835
Sludge
Oper. &
Maint.
600
600
1,190
1,190
1,970
1,970
Total
Ann. Cost
325
1,875
2,200
665
3,580
4,245
1,080
5,725
6,805
-------
TABLE 116
FINE KRAFT SUBCATEGORY
BPCTCA Effluent Treatment Costs
(all costs in thousands of dollars)
Mill Size: 250 TPD
Internal
External
Total
Mill Size: 670 TPD
Internal
External
Total
Mill Size: 1300 TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Capital
Cost
1,800
5,860
7,660
2,870
10,575
13,445
5,570
15,870
21,440
Aerated Stabilization
Ann. Fixed Oper.
Charges Maint .
300
965 430
1,265 430
470
1,745 895
2,215 895
920
2,620 1,515
3,540 1,515
Basin
& Total
Ann. Cost
300
1,395
1,695
470
2,640
3,110
920
4,135
5,055
Capital
Cost
1,800
7,310
9,110
2,870
13,655
16,525
5,570
20,810
26,380
Activated
Ann. Fixed
Charges
300
1,205
1,505
470
2,255
2,725
920
3,435
4,355
Sludge
Oper. &
Maint.
1,225
1,225
1,175
1,175
1,935
1,935
Total
Ann. Cost
300
2,430
2,730
470
3,430
3,900
920
5,370
6,290
-------
TABLE 117
GROUNDWUOD CHEMI-MECH. SUBCATEGORY
BPCTCA Effluent Treatment Costs
(all costs in thousands of dollars)
Mill Size: 100 TPD
Internal
External
Total
Mill Size: 300 TPD
Internal
External
Total
Mill Size: 600 TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Capital
Cost
430
4,115
4,545
745
7,780
8,525
1,100
11,925
13,025
•
Aerated Stabilization
Ann. Fixed Oper.
Charges Maint .
70
680 290
750 290
125
1,285 670
1,410 670
180
1,970 1,175
2,150 1,175
Basin
& Total
Ann. Cost
70
970
1,040
125
1,955
2,080
180
3,145
3,325
Capital
Cost
430
4,480
4,910
745
8,745
9,490
1,100
13,700
14,800
Activated
Ann. Fixed
Charges
70
740
810
125
1,445
1,570
180
2,260
2,440
Sludge
Oper. &
Maint.
425
425
880
880
1,515
1,515
Total
Ann. Cost
70
1,165
1,235
125
2,325
2,450
180
3,775
3,955
en
IN)
-------
TABLE 118
GROUNDWOOD THERMO-MECH. SUBCATEGORY
BPCTCA Effluent Treatment Costs
(all costs in thousands of dollars)
Mill Size: 10° TPD
Internal
External
Total
Mill Size: 300 TPD
Internal
External
Total
Mill Size: 600 TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Capital
Cost
430
2,905
3,335
745
5,340
6,085
1,100
8,095
9,195
Aerated Stabilization
Ann. Fixed Oper.
Charges Maint
70
480 200
550 200
125
880 395
1,005 395
180
1,335 645
1,515 645
Basin
& Total
Ann. Cost
70
680
750
125
1,275
1,400
180
1,980
2,160
Activated Sludge
Capital
Cost
430
2,325
2,755
745
4,370
5,115
1,100
6,800
7,900
Ann. Fixed Opcr. &
Charges Maint.
70
385 220
455 220
125
720 420
845 420
1*0
1,120 675
1,300 675
Total
Ann. Cost
70
605
675
125
1,140
1,265
180
1,795
1,975
01
CO
-------
TABLE
GROUNDWOOD FINE PAPERS SUBCATEGORY
BPCTCA Effluent Treatment Costs
(all costs in thousands of dollars)
Mill Size: 150 TPD
Internal
External
Total
Mill Size: 300 TPD
Internal
External
To ta 1
Mill Size: 550 TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Capital
Cost
, 450
3, 540
3,990
800
5,150
5,950
1,410
7,350
8,760
Aerated Stabilization
Ann. Fixed Oper.
Charges Maint
75
585 225
660 225
130
850 335
980 335
230
1,215 500
1,445 500
Basin
& Total
Ann. Cost
75
810
885
130
1,185
1,315
230
1,715
1,945
Activated Sludge
Capital
Cost
450
4,090
4,540
800
6,070
6,870
1,410
8,800
10,210
Ann. Fixed Oper, &
Charges Maint,
75
675 310
750 310
130
1,000 440
1,130 440
230
1,450 640
1,680 640
Total
Ann. Cost
75
985
1,060
130
1,440
1,570
230
2,090
2,320
-------
en
tn
TABLE i20
GROUNDWOOD CMN PAPERS SUBCATEGORY
BPCTCA Effluent Treatment Costs
(all costs in thousands of dollars)
Mill Size: 75 TPD
Internal
External
Total
Mill Size: 150 TPD
Internal
External
Total
Mill Size: 500 TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Capital
Cost
335
2',570
2,905
500
3,690
4,190
1,205
7,290
8,495
Aerated Stabilization
Ann. Fixed Oper.
Charges Maint
55
425 160
480 160
85
610 225
695 225
200
1,205 460
1,405 460
Rasin
& Total
Ann. Cost
55
585
640
85
835
920
200
1,665
1,865
Capital
Cost
335
2,970
3,305
500
4,305
4,805
1,205
8,740
9,945
Activated
Ann. Fixed
Charges
55
490
545
85
710
795
200
1,445
1,645
Sludge
Oper. &
Maint.
230
230
315
315
590
590
Total
Ann. Cost
55
720
775
85
1,025
1,110
200
2,035
2,235
-------
TABLE 121
SODA SUBCATEGORY
BPCTCA Effluent Treatment Costs
(all costs in thousands of dollars)
Mill Size: 300 TPD
Internal
External
Total
Mill Size: 700 TPD
Internal
External
To ta 1
Mill Size: TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Aerated Stabilization Basin
Capital Ann. Fixed Oper. & Total
Cost Charges Maint. Ann. Cost
1,875 310 — 310
7 ,'815 1,290 675 1,965
9,690 1,600 675 2,275
3,780 625 — 625
12,930 2,135 1,245 3,380
16,710 2,760 1,245 4,005
Activated Sludge
Capital Ann. Fixed Oper. & Total
Cost Charges Maint. Ann. Cost
1,875 310 — 310
9,505 1,570 835 2,405
11,380 1,880 835 2,715
3,780 625 — 625
16,000 2,640 1,960 4,600
19,780 3,265 1,960 5,225
-pi
C)
CTl
-------
TABLE 122
PAPER GRADE SULFITE (BLOW PIT) SUBCATEGORY
BPCTCA Effluent Treatment Costs
(all costs in thousands of dollars)
CT)
CT)
Mill Size: 1 60 TPD
Internal
External
Total
Mill Size: 530 TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Mill Size: TPD
Internal
External
To ta 1
Aerated Stabilization Basin
Capital Ann. Fixed Oper. & Total
Cost Charges Maint. Ann. Cost
3,330 550 565 1,115
7,545 1,245 530 1,775
10,875 1,795 1,095 2,890
7,620 1,260 1,605 2,865
15,785 2,605 1,390 3,995
23,405 3,865 2,995 6,860
Activated Sludge
Capital Ann. Fixed Oper. &
Cost Charges Maint.
3,330 550 565
8,745 1,440 745
12,075 1,990 1,310
7,620 1,260 1,605
18,985 3,130 1,825
26,605 4,390 3,430
Total
Ann. Cost
1,115
2,185
3,300
2,865
4,955
7,820
-------
-------
TABLE 123
PAPER GRADE SULFITE (VACUUM DRUM) SUBCATEGORY
BPCTCA Effluent Treatment Costs
(all costs in thousands of dollars)
Internal
External
Total
Mill Size:
Internal
External
Total
Mill Size: 16QTPD
Internal
External
Total
Mill Size: 530 TPD
Internal
External
Total
Mill Size: TPD
Aerated Stabilization
Capital
Cost
3,330
7,210
10,540
7,260
14,935
22,555
Ann. Fixed
Charges
550
1,190
1,740
1,260
2,465
3,725
Oper .
Maint
565
590
1,155
1,605
1,400
3,005
Basin
& Total
Ann. Cost
1,115
1,780
2,895
j
\
2,865
3,865
6,730
Capital
Cost
3,330
8,465
11,795
7,620
17,380
25,000
Activated
Ann. Fixed
Charges
550
1,400
1,950
1,260
2,870
4,130
Sludge
Oper . &
Maint .
565
700
1,265
1,605
1,655
3,260
Total
Ann. Cost
1,115
2,100
3,215
2,865
4,525
7,390
TPD
-------
TABLE 124
DISSOLVING SULFITE - NITRATION SUBCATEGORY
BPCTCA Effluent Treatment Costs
(all costs in thousands of dollars)
oo
Mill Size: 550 TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Aerated Stabilization Basin
Capital Ann. Fixed Oper. & Total
Cost Charges Maint. Ann. Cost
4,695 775 1,665 2,440
17,430 2,875 1,560 4,435
22,125 3,650 3,225 6,875
Activated Sludge
Capital Ann. Fixed Oper. & Total
Cost Charges Maint. Ann. Cost
4,695 775 1,665 2,440
21,525 3,550 2,040 5,590
26,220 4,325 3,705 8,030
-------
TABLE "125
DISSOLVING SULFITE - ACETATE SUBCATEGORY
BPCTCA Effluent Treatment Costs
(all costs in thousands of dollars)
en
Mill Size: 550 TPD
Internal
Ex tc- rnal
Total
Mill Size: TPD
Internal
External
Total
Aerated Stabilization Basin
Capital Ann. Fixed Oper. & Total
Cost Charges Maim. Ann. Cost
4,695 775 1,665 2,440
20,330 3,355 1,950 5,305
25,025 4,130 3,615 7,745
.
!
1
Mill Size: TPD j
Internal
External
Tot a 1
Mill Size: TPD
Internal
External
Total
Activated Sludge
Capital Ann. Fixed Oper. & Total
Cost Charges Maint. Ann. Cost
4,695 775 1,665 2,440
24,290 4,010 2,595 6,605
28,985 4,785 4,260 9,045
-------
TABLE 126
DEINK SUBCATEGORY
BPCTCA Effluent Treatment Costs
(all costs in thousands of dollars)
Mill Size: 80 TPD
Internal
External
Total
Mill Size: 230 TPD
Internal
External
Total
Mill Size: 500 TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Capital
Cost
790
3,900
4,690
1,475
7,105
8,580
2,810
11,290
14,100
Aerated Stabilization
Ann. Fixed Oper.
Charges Maint .
130
645 310
775 310
245
1,170 650
1,415 650
465
1,865 1,160
2,330 1,160
Basin
& Total
Ann. Cost
130
955
1,085
245
1,820
2,065
465
3,025
3,490
Activated Sludge
Capital
Cost
790
4,325
5,115
1,475
7,985
9,460
2,810
12,805
15,615
Ann. Fixed Oper. &
Charges Maint.
130
715 410
845 410
245
1,320 795
1,565 795
465
2,115 1,355
2,580 1,355
Total
Ann. Cost
130
1,125
1,255
245
2,115
2,360
465
3,470
3,935
-------
TABLE 127
NI FINE PAPERS SUBCATEGORY
BPCTCA Effluent Treatment Costs
(all costs in thousands of dollars)
Mill Size: 30 TPD
Internal
External
Total
Mill Size: 100 TPD
Internal
External
Total
Mill Size: 280 TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Capital
Cost
215
1,085
1,300
435
1,875
2,310
1,165
3,160
4,325
Aerated Stabilization
Ann. Fixed Oper.
Charges Maint
35
180 105
215 105
70
310 165
380 165
190
520 255
710 255
Basin
& Total
Ann. Cost
35
285
320
70
475
545
190
775
965
Capital
Cost
215
1,250
1,465
435
2,320
2,755
1,165
4,300
5,465
Activated
Ann. Fixed
Charges
35
205
240
70
385
455
190
710
900
Sludge
Oper. &
Maint.
135
135
200
200
305
305
Total
Ann. Cost
35
340
375
70
585
655
190
1,015
1,205
-------
TABLE 128
NONINTEGRATED TISSUE SUBCATEGORY
BPCTCA Effluent Treatment Costs
(all costs in thousands of dollars)
Mill Size: 15 TPD
Internal
External
Total
Mill Size: 35 TPD
Internal
External
Total
Mill Size: HO TPD
Internal
External
Total
Mill Size: 450 TPD
Internal
External
Total
Aerated Stabilization
Capital
Cost
225
550
775
430
840
1,270
840
1,520
2,360
2,380
3,300
5,680
Ann. Fixed
Charges
35
90
125
70
140
210
140
250
390
395
545
940
Oper.
Maint.
75
75
90
90
135
135
260
260
Basin
& Total
Ann. Cost
35
165
200
70
230
300
140
385
525
395
805
1,200
Activated Sludge
Capital Ann. Fixed Oper. & Total
Cost Charges Maint. Ann. Cost
-------
TABLE 129
BPCTCA Effluent Treatment Costs
(all costs in thousands of dollars)
Mill Size: TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Mill Size: TPD
Internal
External
Total
Aerated Stabilization
Capital
Cost
225
1,185
1,410
430
1,710
2,140
840
3,010
3,850
2,380
6,475
8,855
Ann. Fixed
Charges
35
195
230
70
280
350
140
495
635
395
1,070
1,465
Oper .
Maint
110
110
150
150
260
260
620
620
Basin
& Total
Ann. Cost
35
305
340
70
430
500
140
755
8Q5
395
1.6QO
2,085
Capital
Cost
225
1,445
1,670
430
2,140
2,570
840
3,920
4,760
2,380
8,720
11, 100
Activated
Ann. Fixed
Charges
35
240
275
70
355
425
140
645
785
395
1,440
1,835
Sludge
Oper. &
Maint.
150
150
205
205
335
335
110
710
Total
Ann. Cost
35
390
425
70
560
630
140
980
1,120
395
2,150
2,545
-------
IMPACT OF CLIMATE VARIATIONS
Effluent treatment systems constructed in northern climates
often require more design consideration than facilities
constructed in the south. Problems associated with winter
or cold climate operation require that certain provisions be
included. For instance, in the south, most mills construct
their facilities with open pump pits, above ground piping,
exposed process equipment, etc. Mills located in the north,
however, are unable to utilize such designs.
The operational costs associated with a treatment facility
located in the north in general may te greater than that for
a southern facility. These increased operational costs can
be attributed to (1) increased energy unit costs, and (2)
maintenance of additional facilities.
A major factor contributing to increased capital and
operating expenditures for northern climates is variations
in temperature. Such variations, as discussed in Section
VII, can have an impact on the BOD5 and TSS levels in the
effluents of aerobic biological treatment systems. In order
for the mills located in the northern climates of the United
States to meet the effluent limitations, it is necessary
that they utilize an aerobic biological system which
minimizes the effects of cold climate. From investigations
it can be concluded that the decrease in removal
efficiencies across biological systems is related to the
temperature drop across the system. Consequently, systems
utilizing short detention times which minimize the heat
transfer through the system should reduce the effects of
temperature variations.
Cost estimates for systems capable of complying with the
effluent limitations in northern climates have been prepared
to assess economic impact. These estimates were prepared
for a representative northern mill to provide a basis for
comparison with national averages. This is discussed in
more detail below.
After review of the various pulp and paper subcategories, it
was determined that the Fine Kraft subcategory best
represented the average capital expenditure required for
construction of an effluent treatment facility. Of course,
several categories were reported as having higher
expenditure and there were several categories with less
expenditures. A 608 kg/day (670 TPD) fine kraft mill was
selected as the representative mill. Influent and effluent
concentrations specified herein for BPCTCA were utilized in
preparation of the cost estimates.
474
-------
Several unit processes are common to all of the aerobic
biological treatment systems considered. The additional
processes included in the systems are (1) preliminary
treatment, (2) mill effluent pumping, (3) primary
clarification, (U) neutralization, (5) secondary
clarification, (6) foam control, (7) outfall with multi-port
diffuser, (8) air flotation, (9) vacuum filtration, (10) V-
press, and (11) emergency sludge lagoon.
The four (4) alternative treatment systems considered were:
1. Conventional Activated Sludge - Conventional activated
sludge systems are normally designed with a detention
time of 6-8 hours. Because of the short detention
times, this process is subject to severe upsets because
of variations in waste water flows and shock loadings.
An equalization basin (12-hour detention) is included in
this system to minimize process shock loadings and
upsets of the treatment system. The process design
criteria are:
Detention Time 6-8 hours
F/M Ratio 0.3-0.5
Organic Loading 50f BOD/1000 FT3
02 Transfer 1.75* 02/HP-Hr
O2. Requirement 1.0* O2/BODR
2. Extended Aeration - Because of the larger detention
times in the aeration basin, process upsets will not be
as critical as with a short-term activated sludge
system. Therefore, an equalization basin has not been
included in this cost study. It is recognized and noted
that in certain mills such a facility could potentially
be required. The process design criteria are:
Detention Time 30 Hours
F/M Ratio 0.1
Organic Loading 20-40* BOD/1000 FT3_
O2 Transfer 1.75* 02/HP-Hr.
O2. Requirement 1.25* O.2/*BODR
3. High-Purity Oxygen - A manufacturer of high-purity
oxygen equipment was contacted to obtain suggested
design criteria and budgetary cost estimates for a high-
purity oxygen system. From this and other data, the
following design criteria has been developed:
Detention Time 1.8 Hours
F/M Ratio 0.65
Organic Loading 138* BOD/1000 FT3_
475
-------
An equalization basin is included in the system for
minimization of process upsets.
4. Rotating Biological Surfaces - Rotating Biological
Surfaces have received limited acceptance by the pulp
and paper industry in northern climates. Typical design
criteria are:
Detention Time 2.0 Hours
F/M Ratio 1.5
Organic Loading 2.2 Gal/Day/FT2_
An enclosure was provided to house the process
equipment. Again, an equalization basin was provided.
As mentioned previously, minimization of temperature
reduction through an aerobic biological treatment system is
essential. Each of the above described systems should
minimize temperature reduction through the system because of
its relatively short detention time. The equalization basin
suggested for use in several of the systems is a tank which
would be constructed at the maximum economical depth to
minimize surface area. Temperature reductions through these
equalization basins would be less than those for a
comparable aerated facility where mixing exposes
substantially additipnal water to the ambient temperature.
The extended aeration system considered utilizes an aeration
period of approximately 30 hours. This system would be more
susceptible to a temperature drop, with a corresponding
decrease in BOD.5 rate and increase in suspended solids in
the effluent. This is primarily due to the detention time
and the exposed surface area.
The costs presented in Tables 113-129 were for
representative "model" mills. Construction in the north
potentially could require a slight increase in capital and
operation expenditure, while one in the south may require
slightly less expenditure due to process considerations.
Figure 88 presents the anticipated capital expenditures
required for construction of an effluent treatment facility
in northern climates.
Technology applicable to northern climates are included in
Tables 113-129, in that costs for activated sludge systems
have been included in addition to aerated stabilization
basins.
476
-------
A sample calculation showing how the costs presented in
Tables 113-129 were developed is shown on the following
pages. For illustrative purposes the example is a 608
kkg/day (670 TPD) BCT bleached kraft mill.
477
-------
co
cr
o
o
UJ
CO
cr
o
o
CO
o
o
100
FIGURE sa
EFFLUENT TREATMENT
FACILITY
NORTHERN CLIMATE
100
670 TPD
FINE KRAFT MILL
478
-------
SAMPLE CALCULATION
Subcategory: BCT Bleached Kraft
Mill Size: 670 Tons Per Day
Technology level: BPCTCA
INTERNAL COSTS
A. Capital Costs
Item 1 High Level Alarms on Tanks
Item 4 Use of Mill Wastewater in Woodyard
Item 7 Decker Filtrate for Sulfite Pit Dilution
or Vacuum Washer Showers
Item 8 Knot Collection and Disposal or Reuse
Item 9 Turpentine Collection
Item 10 Soap Collection
Item 14 Evap. Cond. for B.S. Washer Showers
Item 16 Recook Screen RM Rejects
Item 17 Jumpstage Counter Current Washing in
Bleach Plant with Reuse of Chlorina-
tion Filtrate
Item 20 Chlorine Dioxide Waste Acid Use
Item 24 Reuse Kiln Scrubber Water
Item 25 Use of Green Liquor Dregs Filtrate
Item 26 Evap. Cond. for Causticizing Make-up
Item 29 Paper Machine w.w. Showers for Wire
Cleaning
Item 34 W.W. Storage for Upset & Pulper Dilution
Item 35 Broke Storage & Overflow Prevention
Item 37 Install Save-all Board - $ 489,600
Tissue - 1,205,600
Total Capital Cost
Int. & Dep. @ 16.5%
Capital Cost
$ 18,800
60,600
260,200
60,000
92,000
118,600
162,600
29,600
159,400
42,800
8,500
91,300
93,300
187,400
542,000
399,300
1,695,200
$4,021,600
663,600
479
-------
B. Energy requirement for BPCTCA internal controls. KW-HR/Ton
figures reflect net energy savings or loss from all BPCTCA
controls. Thermal and electrical energy were considered
and converted to KW-HR.
Item 1 High Level Alarms on Tanks
Item 4 Use of Mill Wastewater in Woodyard
Item 7 Decker Filtrate Vacuum Washer
Showers
Item 8 Knot Collection and Disposal or Reuse
Item 9 Turpentine Collection
Item 10 Soap Collection
Item 14 Evap. Cond. for B.S. Washer Showers
Item 16 Recook Screen Room Rejects
Item 17 Jumpstage Counter Current Washing in
Bleach Plant with Reuse of Chlori-
nation Filtrate
Item 20 Chlorine Dioxide Waste Acid Use
Item 24 Kiln Scrubber Water
Item 25 Green Liquor Dregs
Item 26 Evap. Cond. for Causticizing Make-up
Item 29 W.W. Showers for Wire Cleaning
Item 34 W.W. Storage for Upset & Pulper Dilution
Item 35 Broke Storage & Overflow Prevention
Item 37 Save all Installation (Tissue)
Net KW-HR/Ton
KW-HR/Ton
Negligible
.36
3.30
.37
7.2
1.05
.99
.09
9.8
.22
.20
.34
.32
2.05
1.0
Negligible
56.2
Additional
Additional
Additional
Additional
Saving1
Additional
Additional
Additional
o
Additional
Additional
Additional
Additional
Additional
Additional
Additional
Additional
Additional
69
Additional'
^-Savings in Thermal Energy - BTU/Ton Converted to KW-HR/Ton for
670 Ton/Day BCT Kraft Mill; 1348 x 670 = 9.03 x 105 KW-HR
Day
(9.03 x 105) (360 Days/Yr) (3414.4 BTU ) = 1.11 x 1012 BTU/Year
KW-HR
Saving @ 31.70/106 BTU
$1.89 x 106/Year
2Does not include thermal energy savings of 863.8 KWH-ton.
480
-------
C. Operating and Maintenance Costs
1. The details of operating and maintenance cost calculations are
illustrated using item 14, Evaporator Condensates for Brown
Stock Washer Showers.
For 670 TPD BL Kraft Mill
Electrical Requirement: 2-20 HP Pumps Continuous Service
(40 HP) (.746 KW/HP) = 29.8 KW
(29.8 KW) (24 Hr/Day) = 715.2 KWHR/Day
(715.2 KWHR/Day)/(360 T/Day) = 1.987 KWHR/Ton Pulp
Electrical Cost @ $18.50/1000 KWHR
(2 KWH/Ton) (670 Ton/Day) (360 Day/Year) ($18.50/1000 KWH)
= $8,900/Yr.
Water Savings:
(970 GPM) (1440 Min/Day) (360 Day/Year) = 503 x 106 Gal/Yr
(503 x 106 Gal/Yr) ($70/106 Gal) = $35,200/Year
Heat Cost:
A. Base system using fresh water to raise water temperature
from 60°F to 140°F
(503 x 106 Gal/Yr) (8.34 ///Gal) (1 BTU///°F) (140-60) =
3.36 x 1011 BTU/Yr
(3.36 x 1011 BTU) ($1.70/106 BTU) = $570,500/Yr
Yr
B. New system w/evap. Condensate to raise water temperature
from 100°F to 140°F
(503 x 106 Gal/Year) (8.34 ///Gal) (1 BTU///°F) (140-100) =
167,800 x 106 BTU/Yr.
(167,800 x 106 BTU/Year) ($1.70/106 BTU) = $285,300/Year
Net Heat Savings $570,500 - 285,300 = $285,200/year
Net Savings = Heat Savings - Electrical Costs + Water Savings
= 285,200 - 8,900 + 35,200
= $311,500/Year
Maintenance Cost:
5% per year of initial capital investment
(.05) (162,600) = $8,100/Year
481
-------
Item 14 contains no fiber or chemical savings. However, for all items
which result in chemical and fiber savings these savings were calcu-
lated in a similar manner to the heat and water savings illustrated
above using appropriate chemical costs from the September 1974 issue
of Chemical Marketing Reporter. The following costs were derived by
averaging the costs for each item obtained during the 1975 EPA Survey
of pulp and paper mills:
Fuel Oil - $0.28/gallon;
Treated Water - $70.30/106 gallons;
Raw Water - $36.00/106 gallons;
Purchased Electricity - $18.50/103 gallons;
Steam - $1.70/106 BTU.
The maintenance cost was varied from 3 to 5 percent per year of initial
capital investment depending on the type of equipment involved.
482
-------
2.
(+ indicates savings, - indicates net cost per year)
Item 1t
1
4.
7.
8.
9.
10.
14.
16.
17.
20.
24.
25.
26,
29,
34.
35.
37. Board
Tissue
Operating
Cost
Negligible
+ 1,300
+ 42,400
+ 66,800
Negligible
4,700
+ 311,500
400
+1,254,500
1,000
900
1,200
+ 12,400
+ 4,700
4,000
Negligible
38,000
57,000
Maintenance
Cost
- 20,000
- 1,800
- 13,000
- 3,000
- 2,800
- 5,900
- 8,100
- 1,200
—
- 2,100
400
- 4,600
- 2,800
- 5,200
- 16,300
- 12,000
- 14,700
- 36,200
Chemical &
Fiber Savings
Variable
—
+109,500
+ 71,000
+395,800
+479,700
—
+ 24,000
—
+335,000
+ 62,600
+ 25,100
—
—
+ 81,700
+ 25,500
+300,400
+450,600
Total Savings
Per Year
Savings
500
+ 138,900
+ 134,800
+ 393,000
+ 469,100
+ 303,400
+ 22,400
+1,254,500
+ 331,900
+ 61,300
+ 19,300
+ 9,600
500
+ 61,400
+ 13,500
+ 247,700
+ 357,400
NOTE: Only Negative Savings Items (4 & 29) were used
in summary Table columns for operating and
maintenance costs.
483
-------
EXTERNAL TECHNOLOGY
A. Design Parameters
WASTE CHARACTERISTICS
'1973"
Flow, kgal/ton
BOD, Ib/ton
TSS, Ib/ton
09 BOD, Ib/day
09 TSS, Ib/day
Flow, mgd (A.A.)
Design Flow, mgd (1.5/1.3)
79 BOD, Ib/day
79 TSS, Ib/day
Control Technologies
Hydraulically Controlled
Desing Flow, mgd
56% of Design Flow
for Clarification
09
50
85.0
110.0
79
77.8
37.2
"BPCTCA"
09 79
35.4
76.7
133
8.0
16.2
'1973"
56,950
73,700
33.5
38.7
52,160
24,910
38.7
21.7
09 BOD, Ib/day
79 BOD, Ib/day
BOD Removal, Ib/day
% BODR
09 TSS, Ib/day
79 TSS, Ib/day
TSS Removal, Ib/day
% TSSR
Sludge Lagoon
20% - 5 yrs, mg
56,950
52,160
4,790
8
73,700
24,910
48,790
66
53
484
-------
BPCTCA
09 BOD, Ib/day 51,390
09 TSS, Ib/day 89,110
Flow, mgd (A.A.) 23.7
Design Flow, mgd (1.5/1.3) 27.3
79 BOD, Ib/day 5,360
79 TSS, Ib/day 10,850
Control Technologies
Hydraulically Controlled
Design Flow, mgd 27.3
485
-------
Aerated Stabilizated Basin
Activated Sludge
09 BOD, Ib/day 51,390
% BODD (1973) 8
K
BOD Applied 47,279
Aerated Stabilization
Basin
Hydraulic Control 382
(rag)(14 day)
Organic Control 308.1
(mg)(50 Ib BODA/AC-FT)
79 BOD, Ib/day 5,360
BOD Removal, BODA~BOD79 41,919
Aerators (ASB), HP 1996.1
1.25 (BODR)(1.6)/(24) (1.75)
09 BOD, Ib/day 51,390
% BODD (1973) 8
K
BOD Applied 47,279
Activated Sludge
Hydraulic Control 9.1
(rag)(8 hrs)
Organic Control 7.09
(mg)(50 Ib BODA/1000 CF)
79 BOD, Ib/day 5,360
BOD Removal, BODA-BOD7q 41,919
/\ * ^
Equil. Basin 13.7
(12 hours detention time)
Activated Sludge, HP 1,597
(BODR) (1.6)/(24) (1.75)
486
-------
SOLIDS PRODUCTION
ACTIVATED SLUDGE
09 TSS, Ibs/day 89,110
% TSSR Ibs/day
Primary Clarification 58,813
(1)
09 - TSSR, Ibs/day
39 TSS 30,297
79 TSS 10,850
.3 (39-79) TSS
Ibs/day 5,834
(2)
.7 (BODR)
(3) 29,343
Total Solids
(l)+(2)+(3) 93,990
Secondary Solids
(2)+(3) 35,177
SOLIDS PRODUCTION
AERATED STABILIZATION BASIN
09 TSS, Ibs/day 89,110
% TSSR (1973) 66
TSSR, Ibs/day 58,813
Primary Clarification
Total Solids 58,813
487
-------
oo
oo
B. Costs
Technology
1. Preliminary
2. Pump Station
3. Primary Clar.
4. Sludge Lagoon
5. Neutralization
6. Equil. Basin
7. Aerators
8. Aeration Basin
9. Sec. Clarification
10. Flotation Thickening
11. Vacuum Filtration
12. Press
13. Monitoring
14. Foam
15. Outfall
16. Diffuser
17. Black Liquor Lagoon
TOTAL COSTS - thousand dollars
(16.5%) ANNUAL FIXED CHARGES - thousand dollars
AERATED STABILIZATION BASIN
(All
Design Parameter
21.7 mgd
38.7 mgd
21.7 mgd
5.3 mg
mgd
mg
1996 HP
382 mg
mgd
thousand Ib/day
58.8 thousand Ib/day
58.8 thousand Ib/day
38.7 mgd
38.7 mgd
38.7 mgd
38.7 mgd
1.68 mgd
liars
costs in thousand dollars)
Capital Costs Operation Costs & Maintenance
190 13
850 72
1,700 26
530
1,700 285
4,100 166
1,075 281
200 31
68 40
85
502
230
100
$11,330 $914
$ 1,870
-------
ACTIVATED SLUDGE
00
IO
Technology
1. Preliminary
2, Pump Station
3. Primary Clar.
4, Sludge Lagoon
5. Neutralization
6. Equil. Basin
7, Aerators
8. Aeration Basin
9. Sec. Clarification
10. Flotation Thickening
11. Vacuum Filtration
12. Press
13. Monitoring
14, Foam
15. Outfall
16. Diffuser
17. Black Liquor Lagoon
TOTAL COSTS - thousand
(All costs in thousand dollars)
Design Parameter Capital Costs
21.7 mgd 190
38.7 mgd 850
21.7 mgd 1,700
5.3 mg 530
mgd
13.7 mg 1,100
1597 HP 1,400
9.1 mg 1,600
27.3 mgd 3,250
35.2 thousand Ib/day 1,150
94.0 thousand Ib/day 1,512
94.0 thousand Ib/day 220
38.7 mgd 68
38.7 mgd 85
38.7 mgd 502
38,7 mgd 230
1.68 mgd 100
dollars $14,487
Operation Costs& Maintenance
13
72
26
220
175
66
177
362
39
40
$1,190
(16.5%) ANNUAL FIXED CHARGES - thousand dollars
$ 2,390
-------
C. Energy Requirements
Technology
1. Preliminary
2. Pump Station
3. Primary Clar.
4. Sludge Lagoon
5. Neutralization
6. Equil. Basin
7. Aerators
8. Aeration Basin
9. Sec. Clarification
10. Flotation Thickening
11. Vacuum Filtration
12. Press
13. Monitoring
14. Foam
15. Outfall
16. Diffuser
17. Black Liquor Lagoon
TOTAL EXTERNAL ENERGY
AERATED STABILIZATION BASIN
(Energy in thousand KW-HR/YR)
Design Parameter
21.7 mgd
38.7 mgd
21.7 mgd
mg
mgd
mg
1996 HP
mg
mgd
thousand Ib/day
58.8 thousand Ib/day
58.8 thousand Ib/day
mgd
mgd
mgd
mgd
mgd
- thousand KW-HR/YR
Power
14
2,450
115
14,000
320
145
17,044
-------
Technology
1. Preliminary
2. Pump Station
3, Primary Clar.
4, Sludge Lagoon
5. Neutralization
6, Equil. Basin
7. Aerators
8. Aeration Basin
9, Sec. Clarification
10. Flotation Thickening
11. Vacuum Filtration
12. Press
13. Monitoring
14, Foam
15. "Outfall
16. Diffuser
17. Black Liquor Lagoon
ACTIVATED SLUDGE
(Energy in thousand KW-HR/YR)
Design Parameter
21.7 mgd
38.7 mgd
21,7 mgd
mg
mgd
mg
1597 HP
mg
27.3 mgd
35.2 thousand Ib/day
94,0 thousand Ib/day
94.0 thousand Ib/day
mgd
mgd
mgd
mgd
rag
Power_
14
2,450
115
11,000
1,200
620
1,000
250
TOTAL EXTERNAL ENERGY - thousand KW - HR/YR
16,659
-------
ENERGY REQUIREMENTS
Assessment of the impact of the effluent limitations on
energy consumption requires determination of the baseline
energy consumption. Such assessment of baseline conditions
must include steam generation in addition to electrical
consumption. Table 130 presents the baseline energy
requirements for each subcategory. In completing this
assessment, actual mill energy data has been utilized.
Based on anticipated operating hours and steam requirements
the baseline requirements were developed.
In estimating the energy consumption of the control and
treatment technologies, equipment manufacturers were
contacted to determine electrical requirements of an
operation of the major process equipment items. Based on
the anticipated horsepower demands and operational times,
the energy consumption was determined for the control and
treatment technologies. Electrical energy projections for
BPCTCA are also shown in Table 130 on a per kkg (ton) of
production basis.
WASTE SLUDGE DISPOSAL
During the past several years, a large number of waste water
treatment systems have been installed to treat the waste
water from the pulp and paper industry. One common
characteristic of nearly all of these treatment systems is
that they remove solids from the waste water stream. At
some larger mills the quantity of waste water solids may be
as great as 136 kkg (150 tons) per day on a dry weight
basis. When dewatered to a dryness of 40% solids, this
quantity of sludge will require approximately 363 cu m (480
cubic yards) per day, or 129,520 cu m (105 acre-feet) per
year of disposal capacity.
The disposal of this quantity of waste water sludge
represents a substantial environmental problem to the pulp
and paper industry. The waste water sludges may originate
in the primary clarifiers, in which case they would consist
primarily of wood fibers, bark, grit, and paper fillers, or
they may originate in the secondary clarifiers, in which
case they would consist primarily of biological solids
generated in the secondary treatment process. The industry
has developed many diverse methods of dewatering these
sludges to minimize handling and disposal problems. They
are either thickened and dewatered to a solids content of 17
to 30% on vacuum filters or centrifuges, or dewatered to a
solids content of from 40 to 50% on one of several pressing
492
-------
TABLE 130
TOTAL MILL ENERGY REQUIREMENTS
BASELINE AND ADDITIONAL
Subcategory
Groundwood
chemi-mech,
Groundwood
thermo-mech.
Groundwood Fine
Groundwood CMN
Dissolving Kraft
Market Kraft
BCT Kraft
Fine Kraft
Soda
Deink
Nonintegrated Fine
Nonintegrated Tissue
Steam Mil BTU/ton
17
16
15
15
24
23
24
24
24
11
9
7
(FWP) 8
Elect. KW-HR/ton
1700
1800
1900
1800
1050
1000
1300
1400
1300
500
700
425
425
Baseline
Total KW-HR/ton
6680
6485
6290
6190
8075
7735
8325
8425
8325
3720
3335
2475
2765
Additional
BPCTCA
140
68
43
46
1301
861
1391
881
182
130
30
67
87
-------
TABLE 130 (Continued)
TOTAL MILL ENERGY REQUIREMENTS
BASELINE AND ADDITIONAL
Subcategprj Steam Mi 1 BTU/1on
Sulfite - Blow Pit
Sulfite - Vacuum Drum
Dissolving Sulfite -
Nitration
Dissolving Sulfite -
Acetate
23
23
23
23
Elect.KW-HR/ton
1250
1250
1600
1600
Baseline
Total KW-HR/ton
7735
7735
8085
8085
Additional
BPCTCA
1400
1368
1400
1471
Does not include thermal energy savings of 864 KW-HR/ton for jump stage counter current washing.
-------
systems. As the solids content of the sludge increases, the
cost of the dewatering system also increases.
The following is a discussion of the land disposal systems
associated with sludges dewatered in accordance with BPCTCA.
This technology includes the pressing of sludges to a solids
concentration of at least 10%. Because of the problems and
costs associated with the land disposal of waste water
sludges, some mills incinerate the sludges in hogged fuel
boilers to recover some of the energy value in the wood
fibers or in conventional sludge incineration systems,
without heat recovery. No conventional multiple hearth or
fluidized bed sludge incineration systems are now operating
in the pulp and paper industry due to operating problems and
the high operating costs of these systems.
It is recognized that many mills have not installed pressing
systems to dewater their waste water sludges. In these
instances, the mills are faced with the task or disposing of
waste water sludge with a solids content of approximately
20%. The problems associated with the disposal of this
sludge are significantly greater than those associated with
the disposal of a 40% sludge. These problems as well as
techniques for overcoming them are discussed later.
The primary environmental problem associated with the
disposal of waste water sludges is the potential for
contaminating ground and surface waters. Ground and surface
water contamination will occur when leachate generated by
the sludge comes in contact with uncontaminated waters.
Leachate will be formed if rainfall or runoff is permitted
to contact the sludge or if sludge is placed directly into
ground or surface water. Leachate is also formed as water
drains from the sludge after it is placed on the land. If a
sludge containing 20% solids and 80% water is landfilled,
water will be forced out of the landfilled sludge by gravity
and compression.
The landfilled sludge will ultimately reach an equilibrium
condition with a solids content of from 40 to 50%. Sludge
generated at a daily rate of 45 kkg (50 tons) (dry basis) at
20% solids may release as much as 113,550 1 (30,000 gallons)
per day of highly contaminated leachate through this
process. On the other hand, a similar quantity of waste
water sludge pressed to a solids content of approximately
45% solids will give up practically no leachate in this
manner.
Because of the potential for the contamination of water,
guidelines have been developed by many state environmental
495
-------
protection agencies to minimize the impact of the disposal
of sludge and other solid wastes on the environment. The
primary objective of nearly all the regulations is to
minimize the contact between the waste water sludge and
water. These guidelines normally specify the soils which
are acceptable for solid waste disposal and which will
assure that the impact on ground and surface waters is
minimized. With acceptable soils, groundwater and bedrock
are generally located at least five feet below the surface.
These soils must also contain sufficient silt or fine
material to permit only a slow rate of infiltration. It
should be noted, however, that in many cases adverse
environmental impacts will result when large volumes of
sludge with a 20% solids content are placed on suitable
soils. Because of this factor, great care must be taken in
the design, development, and operation of landfills with a
solids content of 20%-30%. When landfilling sludges which
have a solids content of 40K-5051, the potential for adverse
environmental impact is much less.
If it is not possible to acquire a potential sludge disposal
area which meets all criteria, it may be necessary to modify
the site to make it acceptable to the applicable approval
agencies. These modifications might include leachate
collection and treatment, surface water diversion, or
regrading the disposal area with suitable soil.
As noted earlier, sludges containing only 20X-30SI solids can
release up to 113,550 1 (30,000 gal) per day and more of
highly contaminated (BOD5 over 1000 mg/1) leachate. Even
suitable soils may not have the ability to accept this
loading without adversely affecting ground and surface
waters. Therefore, even prior to using sites which meet the
criteria, studies should be completed to establish the use
of the water resources within the drainage area and to
determine the ability of the soils to accept these loadings.
As a result of these studies, it may be determined that
design criteria similar to those for an unsuitable site are
necessary.
If the soils at a proposed landfill site will not provide
adequate protection for the water resources, provisions must
be made in the design, development and operation to provide
the required protection. This protection will normally
include containment of the sludge using natural soils or
synthetic liners. The leachate may then be collected
without migrating directly to ground or surface water. Once
collected, the leachate must be treated in one of several
potential systems:
496
-------
1. If the landfill is located close to a waste water
treatment system, it can be transported to that facility
for processing. Prior to doing this, however, the
impact of the additional loading on the treatment system
must be evaluated. This approach is now being employed
at operating pulp and paper mill waste water sludge
landfills.
2. If the landfill site is remotely located, the leachate
may be treated by a land application system.
Alternative systems include:
a. Spray Irrigation
b. Flood Irrigation
c. Overland Flow
The use of these systems is dependent on climatic, soils
and other conditions which must be considered during
design. Pulp and paper sludge landfill systems have
been designed using these leachate management
techniques.
3. If the alternatives listed above are not feasible,
biological (aerobic or anaerobic) or a physical-chemical
treatment system could be constructed.
The volume of leachate generated can be minimized by proper
design and operation. This can best be accomplished by:
1. Developing the landfill in small phases which minimizes
the area of sludge exposed to precipitation and reduces
the area of the landfill to be maintained.
2. Closing each phase of the landfill upon completion
utilizing a relatively impervious cover followed by
seeding.
3. Proper control of surface drainage outside of the fill
area to assure diversion of all surface runoff away from
the sludge and the leachate collection system.
Another problem associated with the land disposal of waste
water sludges is the acquisition of acceptable sites.
Acceptable sites must have proper soils and topography, must
be located within an acceptable distance from the mill, and
must be obtainable. The number of sites of adequate size
meeting all of these criteria is limited for each mill.
Once a potential site has been identified, further obstacle
to implementation is the gaining of public acceptance and
ultimately the necessary approvals. Regardless of the
497
-------
location of the disposal area, there will normally be at
least some public opposition to its use, even when all
environmental regulations are being met. A major
environmental goal of the pulp and paper industry over the
next several years should be to place emphasis on the proper
management of sludge landfills in order to establish
credibility and gain public acceptance of these practices.
This public acceptance will be important in the future as
new disposal sites are required.
Costs of Sludge Disposal
Estimates for the costs associated with the disposal of
waste water sludges from the pulp and paper industry have
been developed. The costs are based on 1974 prices. These
costs are based upon the land disposal of sludge which has
been dewatered to a solids concentration of 40X. Figure 89
shows the capital costs associated with the development,
site clearing, site preparation, drainage control, leachate
management (as required for sludges with 40-50% solids
concentrations), access roads, gates, fencing, and
equipment. Land costs are excluded. The costs are
presented in terms of dollars per dry ton of sludge
generated per day and are based on a site with a life of
five years. This life was selected since sites with more
than five years' life may be difficult to acquire.
The initial development costs would not change significantly
with sites with longer lives because the development would
be completed in phases comprising no more than five year
increments. Future development would be completed in
conjunction with routine operation and maintenance
procedures.
Operational costs are also presented for sludge landfills in
Figure 90. The costs are presented in terms of dollars per
dry ton of sludge landfilled per day, and include labor,
equipment operation and depreciation, miscellaneous
equipment rental needed for landfill operations, cover
material, learning and seeding for completed portions of the
fill, and supervision and monitoring. The costs are
developed on the basis that the landfill would be attended
during one shift per day.
Sludge hauling costs have been developed as shown in Figure
91 to reflect the costs of transporting waste water sludge
from the dewatering facility to the landfill. Because the
location of sludge disposal sites varies from mill to mill,
curves have been developed for three different haul
distances: 1) two mile round trip; 2) ten mile round trip;
498
-------
ISO T
QC
4
o
o
to
3
O
o
o
_l
<
E
o
IOO -
LANDFILL CAPITAL COSTS
WASTEWATER SLUDGE at 40% SOLIDS
5O -
O
20
40
I
60
80
100
I
120
TONS/DAY-WASTEWATER SLUDGE
DRY BASIS
I4O I6O
FIGURE 89
-------
12 n
LANDFILL OPERATING COSTS
WASTEWATER SLUDGE at 40% SOLIDS
V)
Q
10 -
en
o
o
o:
o
z
o
(rt
o
o
o
a:
IU
a.
o
8 -
6 -
4 -
2 -
2O
40 60 80 IOO
TONS/DAY-WASTEWATER SLUDGE
DRY BASIS
120
140 160
FIGURE 90
-------
10 -
LANDFILL TRANSPORTATION COSTS
WASTEWATER SLUDGE at 40% SOLIDS
8 -
U1
o
o
tn
o
z
o
o
o
o
or
LU
(L
O
6 -
4 -
HAUL MILES FOR ROUND TRIP
20 MILES
10 MILES
2 MILES
2 -
50 100
TONS/DAY WASTEWATER SLUDGE
DRY BASIS
150
FIGURE 91
-------
3) twenty mile round trip. Included in these costs are
labor, truck operations and maintenance, and truck
depreciation. Excluded is the cost of placing the sludge in
the truck because of the number of variables. At some
facilities sludge falls directly from the dewatering system
into the vehicle. This requires minimum rehandling of the
sludge and minimizes the cost of sludge loading. At other
facilities sludge is hauled only 8 hours per day, but is
dewatered 24 hours per day. Under these conditions, sludge
must be stored. Front-end loaders are commonly used to load
the trucks for transport to the disposal area. This
analysis is based on hauling sludge in ten to twelve cubic
yard, ten wheel, dump trucks.
It must be noted that these curves have been developed for
sludge dewatered to a solids concentration of 4031. If
sludge is dewatered ot a concentration of only 20%, the
disposal and transportation costs will increase
significantly. One dry ton of sludge at a 20% solids
concentration will occupy approximately 50-75% more volume
than one dry ton of sludge dewatered to a solids
concentration of 40%. This increased volume of material
will have a direct impact on the sludge hauling costs. The
land disposal cost of a 20% sludge will be greater because
of increased land and cover requirements. The disposal
costs will be further increased because of the handling
problems associated with the wetter sludge and the much
greater potential for leachate generation. A leachate
control system must be an integral part of a landfill,
designed to receive a 20% sludge. Any sludge landfill
designed to receive waste water sludge at concentrations of
20% must include detailed provisions for the management of
the leachate which will drain from the sludge once it is
placed on the land. Natural soils cannot be depended upon
to provide adequate protection to the environment when large
volumes of 20% sludge are landfilled. The cost of the
additional provisions for leachate control are beyond the
costs shown in the figures which are applicable only for
pressed sludge.
The costs of sludge disposal by landfill, as presented
above, have been included in the model mill capital and
operating costs shown in Tables 113-129.
502
-------
COST OF SSL RECOVERY
A study of the economics of an MgO recovery system for a
453.5 kkg (500 ton) per day magnesium bisulfite pulp mill
was conducted and the results are discussed below and
presented in Table 131. Costs were computed at Fall 1974
prices. The Engineering News Record was used to adjust
costs that were not directly available at 1974 prices.
It was found that for a new sulfite mill producing 453.5 kkg
(500 ton) per day of unbleached pulp it would cost $774,000
per year or $4.63 per kkg ($4.20 per ton) of pulp to cover
the fixed plus operating costs of the MgO recovery system.
The firing of spent liquor in the recovery furnace produces
a net flow of 73,550 kkg (162,000 pounds) of steam per hour
from the boiler. Therefore, the capacity of the power
boiler required for a new mill can be reduced from 109,415
kg (241,000 pounds) to 35,865 kg (79,000 pounds) of steam
per hour. The lower cost of the smaller boiler results in a
$1,040,000 savings in capital expense which could be
credited to offset a fraction of the capital expenditure of
$31,250,000 required for the MgO recovery installation.
Since the total capital cost for the MgO recovery system
includes the equipment required for the regeneration of
magnesium bisulfite cooking liquor, the cost for a new mill
would also reflect the savings incurred by the elimination
of the liquor preparation system that would have been
installed in a calcium base sulfite mill. This capital
savings amounts to $621,000.
For an existing sulfite mill, the capital savings on
equipment mentioned above were not included in the cost
calculations. The total fixed plus operating cost for the
addition of an MgO recovery system in an existing mill was
determined to be $1,059,000 per year or $6.28 per kkg ($5.70
per ton) of pulp produced.
The operating costs include additional costs and savings
realized due to the operation of the MgO recovery system
compared with the operating costs of a calcium base sulfite
mill without recovery. Costs under consideration included
the difference in costs of chemicals, electricity, manpower,
maintenance, and fuel.
The cost of chemicals was determined by comparing the cost
of chemicals for calcium base liquor to the cost of makeup
chemicals for magnesium base liquor with a chemical recovery
system. The chemical savings amounts to $1,015,000 per year
for the magnesium base liquor.
503
-------
The additional electrical requirement for the operation of
the liquor recovery system is 181 KWH per kkg (164 KWH per
ton) of pulp. At an average cost of $12 per 1000 KWH, this
results in an electrical cost of $360,000 per year.
Operation of the recovery system requires four men at an
estimated annual cost of $16,000 per man, which covers the
costs of salary, overtime and overhead. The manpower
requirements of the MgO recovery system amount to $256,000
annually.
Maintenance cost information was supplied by an equipment
manufacturer (326). The total maintenance cost for the
recovery system amounted to $500,000 per year. This figure
is a typical maintenance expenditure for an existing MgO
recovery system of similar size. However, it was noted that
this figure could probably be reduced in the future due to
familiarization with the recovery process and design
revisions in the trouble areas. The equipment manufacturer
also supplied order of magnitude capital cost estimates for
power boilers and the MgO recovery system.
Fixed costs of the recovery system include interest and
depreciation and were calculated as 15% of the total
investment. The fixed costs amount to $4,688,000 per year.
The greatest savings incurred by the installation of an MgO
recovery system is the savings in fuel due to the burning of
spent sulfite liquor. The net heat available from the
recovery boiler was calculated by first determining the
gross heat produced in the boiler and then subtracting the
heat required to operate the recovery system. Heat required
for the system includes the heat needed to evaporate the
liquor from 13% solids to 56% solids in a qunituple effect
evaporator plus heat needed to evaporate the remaining water
in the liquor fired to the boiler plus steam required to
operate soot blowers. Converting the net heat available to
its equivalent amount of No. 6 fuel oil, at $10 per barrel,
a saving of $3,730,000 per year results.
With the relative cost of fuel rising, MgO recovery becomes
more attractive. For the 453.5 kkg (500 ton) per day mill
used in the calculations, the break even point for the
magnesium base liquor recovery system installed in a new
mill would be at a price of No. 6 fuel oil of $12.10 per
barrel. For an existing mill the system would break even at
a fuel oil cost of $12.85 per barrel. These break even
figures are calculated using Fall 1974 prices and are
contingent on the stability of other prices used in the
computations.
504
-------
It should also be noted that a mill would not consider a
capital expenditure solely on economic considerations unless
that expenditure would be paid for in a minimum of 5 years
through profits generated through the operation of the
system. Therefore, the evaluation indicates that a mill
would not make the decision to install an MgO recovery
system purely for economic gain but other factors may
justify the installation of recovery systems, such as
physical location of the mill, shortage of chemicals, or
pollution control, since the annual cost of the MgO system
is generally less than two percent of the selling price of
the paper products.
In addition, this general analysis does not eliminate the
possibility of a specific mill making an MgO recovery system
profitable. The variation in capital cost of the recovery
system is the determinant in the profitability of the
specific installation. One mill has reported that the MgO
recovery installation in their 544 kkg (600 ton) per day
mill showed an appreciable return one year after it was put
on line in September 1969 (327) . The profitability of the
system can be attributed to the modification of existing
equipment, availability of space and short piping runs.
505
-------
Table 131
ECONOMICS OF MgO RECOVERY - NEW MILL 500 T/D
VARIABLE OPERATING COSTS
$100Q/yr.
+ 160
Base Costs
Sulfur Costs
Electrical Costs
Manpower Costs
Maintenance Costs
Chemical Savings of MgO
System as compared to Ca.
Chemical Savings of MgO
System as compared to Ca.
$12/1000 KWH
4 men, 4 shifts, $16,000/man
Net Heat Available
Expressed as t6
Oil
FIXED COSTS
Fixed Costs -
Recovery System
Fixed Costs -
Power Boiler
Fixed Costs -
Liquor Prep.
NET OPERATING COST
15% of Investment
Fixed cost savings incurred
by reduction in Power Boiler
size
Savings incurred by eliminna-
tion of Ca Base Liquor
preparation
TOTAL FIXED COST
TOTAL YEARLY COSTS
Total Cost
Total Fixed Cost + Net
Operating Cost
+ 855
- 360
- 256
- 500
+ 25
Total MgO Recovery System
Savings due to smaller power
boiler required
Savings due to elimination
of Ca Base Liquor Preparation + 11
71.3 Ib. f6 Oil/10«» BTU +3730
f6 Oil d $10./bbl.
+ 3665
-4688
+ 156
+ 93
-4439
- 774
+ Denotes Credit
- Denotes Cost
506
-------
Table 131 (Cont'd)
ECONOMICS OF MqO RECOVERY - NEW MILL 500 T/D
INVESTMENT COSTS
Investment Cost
Investment Savings
Investment Savings
Cost of Total recovery
system, Estimate by Babcock
& Wilcox
Due to Reduction in power
boiler size
Due to elimination of Ca base
liquor making system
Million Dollars
31.25
l.OU
.62
NET INVESTMENT COST
ECONOMICS OF MqO RECOVERY - EXISTING MILL 500 T/D
VARIABLE OPERATING COSTS
Base Costs
Sulfur Costs
Electrical costs
Manpower Costs
Maintenance Costs
Neat Heat Available
MgO w/recovery compared to
Ca w/o recovery
Mg/0 w/recovery compared to
Ca w/o recovery
$12/1000 KWH
4 men, U shifts, $16,000/man
Expressed as No. 6 Fuel Oil
3> $10/bbl
NET OPERATING COST
FIXED COST 15% of Investment
TOTAL YEARLY COST
29.59
$1000/yr.
+ 160
+ 855
- 360
- 256
- 500
+ 3730
Operating and Fixed Cost
+ 3629
-U688
-1059
TOTAL INVESTMENT COST
+31,250
507
-------
RETROFIT COSTS
Capital investment costs for mills that must upgrade their
external waste water treatment facilities in order to be in
compliance with the effluent limitations were determined and
are presented below. These costs were predicated on the
following criteria.
1. "Retrofit costs" are determined using only mills with
existing suspended solids removal and biological treatment
facilities. This selection criteria is based on evaluation
of all the pertinent data generated by this study which
established that BPCTCA for all mills in each subcategory is
primary and biological treatment. Mills in the tissue FWP
(predominantly a waste paper furnish) subcategory require
primary and biological treatment but mills using
predominantly virgin pulp are an exception in that these
mills require only primary treatment for EPCTCA. Therefore
the mills in this subcategory that were selected to
determine "retrofit costs" include mills with only primary
treatment facilities.
2. A table listing all mills for each subcategory was
prepared describing the mill size, production and reported
treatment trains. Using the criteria described above,
selection of all the mills in each subcategory or segment to
be used for the determination of retrofit costs were made.
3. Retrofit costs are based on the difference between the
annual average BODJi and TSS actually achieved by each
selected surveyed mill and the average of the annual
averages achieved by the mills used to establish the
effluent limitations for the subcategory. This difference
represented the additional BOD5 and TSS removal required for
each mill. The annual average waste water volume and the
additional BOD5 and TSS removal required for each mill was
then developed. This information as well as mill size and
treatment train is tabulated by the segment in Table 132.
Using the procedures and selection criteria described above
the methodology for the determination of "retrofit costs"
for each subcategory or segment was as follows:
Groundwood Mills
The groundwood segment includes the following subcategories:
chemi-mechanical, thermo-mechanical, groundwood making fine
paper and groundwood making coarse, news and molded paper
products. There are a total of 19 mills that were surveyed
and 20 mills that were not surveyed in this segment and only
508
-------
three mills qualified for determination of retrofit costs.
The remaining mills either discharged to a municipal system,
have no treatment facilities, have only primary treatment
facilities or are in compliance with the effluent
limitations. The design criteria on which "retrofit costs"
are based are described in Table 133. "Retrofit costs11 for
the three mills selected are shown in Table 136.
Sulfite Mills
The sulfite segment includes the sulfite and dissolving
sulfite subcategories. There are 11 mills in this segment
that were subject to detailed survey and 17 mills that were
not. There were only two mills in the entire segment that
qualified for determination of retrofit costs. The
remaining mills discharged to a municipal sewer, have no
treatment, have only primary treatment or are in compliance
with the effluent limitations. The design criteria on which
these costs are based is described in Tatle 133. "Retrofit
costs" for the two mills shown in Table 136 represents the
total costs for the entire sulfite segment.
Soda Subcategory
The two mills listed in Table 132 for the soda subcategory
are the mills that qualify for development of "retrofit
costs" for this subcategory. The costs to upgrade the waste
water treatment facilities for these two mills, i.e.,
"retrofit costs" are shown in Table 136. The design
criteria on which these costs are based is described in
Table 133.
Deink Subcategory
Four mills listed in Table 132 in this subcategory qualified
for selection to determine retrofit costs. The remaining
mills in this subcategory discharged to a municipal system,
have no treatment, have primary treatment only, or are in
compliance with the effluent limitations. The "retrofit
costs" developed for these four mills therefore represent
the costs for the entire subcategory which are shown in
Table 136. The design criteria on which these costs are
based is described in Table 133.
Non-Integrated Fine PaperSubcateqory
The two mills shown in Table 132 provide the basis for
determining "retrofit costs" for this subcategory. The
other mills in this subcategory discharged to a municipal
509
-------
system, have no treatment, have primary treatment only, or
are in compliance with the effluent limitations. The
retrofit costs for this subcategory are shown in Table 138
and the design criteria on which they are based are shown in
Table 133.
Bleached Kraft Mills
The bleached kraft market pulp, dissolving pulp, fine paper
and BCT subcategories are included in this segment. The
twenty-two mills listed in Table 132 under the bleached
kraft segment are those that require the determination of
"retrofit costs." In addition to these mills there are ten
more that were not surveyed, for which retrofit costs must
be determined. There is insufficient data available for
these unsurveyed mills to develop adequate design criteria
on which to base "retrofit costs." Therefore those costs
developed for the surveyed mills which are based on the
design criteria shown in Table 134 approximate retrofit
costs for the unsurveyed mills. The total retrofit costs
for the entire bleached kraft segment were derived using the
procedures described below.
Surveyed Mills
Two of the twenty-two bleached kraft mills listed in Table
132 required no additional capital costs to achieve
compliance. Improved operation and additional chemical
usage appeared to be the probable solution for these mills.
The remaining twenty mills require various improvements in
existing treatment facilities in order to achieve the
additional BODji and TSS removals shown. The design criteria
shown in Table 134 applies for from one to as many as four
mills, all of which are included in the twenty surveyed
mills. The costs to provide the additional treatment
indicated are shown in Table 140 under the surveyed mills
section. The retrofit costs used for the various treatment
levels required are shown in Table 137.
Unsurveyed Mills
The ten mills that require additional treatment facilities
are listed in Table 139, showing mill size and waste water
volume for each mill. The average mill size is 1092 kkg/day
(1200 T/D) and volume is 113.4 MLD (30 MGD) ; therefore, the
retrofit costs developed for the surveyed mills that
averaged 910 kkg/day (1000 T/D) and 121 MLD (32 MGD) were
used to determine retrofit costs for these unsurveyed mills.
Using Table 134, it can be seen that there are ten surveyed
mills requiring from two to ten days additional retention
510
-------
time in their aeration basin. The ten unsurveyed mills all
use aeration basins and it was assumed that the amount of
additional treatment known to be required by the surveyed
mills could reasonably be expected to be required by the
unsurveyed mills. Therefore the retrofit costs developed
for the surveyed mills, increased by a factor of 1.2 to
reflect the larger size of the unsurveyed mills was used to
determine the retrofit cost for these mills. It was also
assumed that the number of mills requiring the differing
levels of treatment would be the same for the ten unsurveyed
mills as was experienced by the ten surveyed mills. The
results of these calculations are shown in Table 140. The
total retrofit costs for the entire segment is also shown in
this table.
Tissue Mills
The tissue subcategories includes the tissue made from
virgin pulp and tissue made from waste paper subcategories.
BPCTCA for the former subcategory is primary treatment and
for the latter, primary treatment plus biological treatment.
The thirteen mills listed in Table 132 are those surveyed
mills that require the determination of retrofit costs. In
addition, there are eleven mills that were not surveyed for
which retrofit costs must be determined. There is
insufficient data available for these unsurveyed mills to
develop adequate design criteria on which to base retrofit
costs. Therefore, those costs developed for the surveyed
mills which are based on the design criteria shown in Table
135 were used to determine approximate retrofit costs for
the unsurveyed mills. The total retrofit costs for the
tissue subcategories were derived using the procedures
described below.
Surveyed Mills
The surveyed mills listed under the tissue segment in Table
132, require various improvements in existing treatment
facilities in order to achieve the additional BODJ5 and TSS
removals shown. The design criteria shown in Table 135 were
derived by grouping the mills by size and whether they used
predominantly virgin pulp or waste paper. The first three
treatment levels shown in Table 135 are for ten mills that
require primary treatment only, i.e., tissue subcategory.
The last treatment level is for three mills that require
biological treatment, i.e., tissue (FWP) subcategory. The
costs to achieve these various treatment levels are shown in
Table 138. These costs are multiplied by the number of
mills to which they apply and a total for each level of
treatment is obtained for each of the four levels of
511
-------
treatment required. These final retrofit costs are shown in
Table 141 under the surveyed mills section.
Unsurveyed Mills
The eleven unsurveyed mills that require additional
treatment facilities are listed in Table 141. For purposes
of developing retrofit costs for these mills, the cost
developed for the surveyed mills for the group of mills that
averaged 39.1 kkg/day (43 T/D) in size, see Table 138, was
used for the first ten mills. To determine the cost for the
eleventh unsurveyed mill, 191 kkg/day (210 T/D), the
retrofit cost developed for the mills that averaged 146
kkg/day (160 T/D) was used, see Table 138. A correction
factor was employed in each calculation to reflect the
difference in size between the unsurveyed mill and the
surveyed mill. The list of unsurveyed mills and the results
of these calculations is shown in Table 141 under the
unsurveyed mills section. The total retrofit costs for the
entire tissue segment is also shown in this table.
ALTERNATIVE TECHNOLOGY
The costs presented in Tables 113-129 represent the costs
for technologies discussed in Section VII and shown in
Figures 85, 86 and 87. As discussed previously, each mill
is unique and because of site or mill specific conditions
alternative technology may be required by a particular mill
for compliance with the limitations. An example might be a
groundwood mill using zinc hydro-sulfite for bleaching. In
order to meet the zinc regulations it may require
supplemental technology or zinc removal. Alternative
technology identified include, but are not limited to, zinc
removal, and incineration.
The cost estimates for these technologies have been
developed as discussed previously. However, the cost index
is approximately 2470 which corresponds to September 1976.
Incineration
At the present time, the most common method for the disposal
of pulp and paper mill waste water sludge is landfilling, as
discussed previously. Generally, sufficient land has been
available to provide the necessary area for the disposal of
these sludges. However, due to land availability and the
adverse impacts of improperly operated facilities,
alternative sludge processing and disposal alternatives
512
-------
TABLE 132
SURVEYED MILLS USED TO DETERMINE
RETROFIT COSTS
Mill
Code
Tons/
Day
Treatment
Train
Flow
M.G.D.
///Day To
BOD
Be Removed
TSS
Groundwood
003
002A
004A
051
052
150
152
140
108
120
110A
136
134
104A
116
118
132
103
107A
112
121A
135
113A
109A
100
501
122A
lllA
102A
542
217
71
296
101
300
638
320
1000
1160
1132
1650
T45
1342
1150
192
417
425
310
6/ 0
1351
936
1177
1119
.1027
1305
598
772
1020
C-TF-C
C-A
SB-SB-SB
C-ASB
C-ASB
C-TF
C-ASB
Blec..
SB-ASB
C-ASB
ASB
ASB
ASB
ASB
A
ASB
A
*
ASB
A
ASB
A?B
ASB
ASB
A
ASB
ASB
ASB
ASB
ASB
13.8
4.9
2.1
Sulfite
ib.b
4.1
Soda
12.0
17.0
:.h.-:d Kraft
6.0
55
36.1
27.8
47.4
21.0
70.2
36.1
5.0
8.1
18.4
9.4
16.9
48 . L'
33.0
39.8
43.8
37.1.
66.1
17.3
?5.0
34.7
6,179
586
277
240
537
19,000
i.e.
2,300
6,300
580
906
3,300
8,978
13,554
13,685
1,133
3,294
7,055
i.e.
i.e.
1,080
1,578
2,539
4,923
21,362
21,745
12,030
i.e.
36,108
3,848
1,259
i.e.
503
i.e.
24,000
24,000
1,200
4 , 000
19,952
3,736
83 , 655
37,044
27,511
83,605
N.A.
i.e.
I . C .
3,689
13,824
O.K.
4,733
N.A.
24 ; 170
i.e.
96,315
i.5,608
772
3,976
I". &» — In -Co
N.A. - No I. Applicable
~ Oy1daLton Lagoon
513
-------
TABLE 132
(continued)
Mill
Code
210
205A
284
257A
252
303
308A
318
333
337
259A
312
313
330
208A
302
329
i.e.
N.A.
Tons/
Day
320
100
375
187
49
45
160
125
163
36
194
15
37
20
104
226
74
= In Compl
Treatment
Train
SB-PS
C-ASB
C-ASB-C
C-A
C-PS
FI
C
C
C
C
C-FI
C-ASB-PS
C-PS
C
C
C-PS
C
lance
Flow
M.G.D.
Deink
6.2
1.9
Fine
2.3
1.9
T^ „ 0.. .
_i_oi>u.c
0.6
2.8
4.4
4.2
5.2
4.5
3.4
0.7
0.2
0.4
1.5
2.8
2.7
#/Day To
BOD
6,003
245
262
430
54
239
560
188
652
508
446
N.A.
644
352
707
226
488
Be Removed
TSS
i.e.
N.A.
i.e.
N.A.
i.e.
N.A.
304
438
N.A.
72
i.e.
590
N.A.
N.A.
62
N.A.
96
= Not Applicable
514
-------
TABLE 133
BASIS ir", Kr.TU'U i'f COST Un.TRMIHATICU:
The fc.l lowing list represents the addition;;! removal requirements to be achieved by
exist in;; primary aiv!. secondary trcarrcnt facilities.
Tons/
75
EOD
TSS
Day MGD 8/\)ay Added Tr entrant Required 9 /Day Added Treatment Required
GrundwcKx! Sejiriftnc
560 13.0 fi20C
220 5.0 60')
2.0
300
Aerators ^ J days retention 4000 Chsriica] fcr.d only
Aerators only in con- Nonf
pliance
Arrator- only " None
300 17.0 300 Aerators only
100 4.0 600 Aerators only
500 none
In con- "ona
pliance
600
300
850
AOO
320
200
100
375
200
17.0 11000
12.0 l°uOO
18.0 300
7.0 8200
6.0 6000
3.0 1000
2.0 300
2.5 270
2.0 450
Aerators + 6 days retention 2AOOO
Aerators + 8 days retention 2ACOO
De ink Sep.rent
Aerators on.ly 3000
Aerators + A days retention 2700
Aerarors + 3 days retention In con-
pliancc
A=r=tcrc- cr.ly 3000
Aerators only 300(5
_S c_gn ant
Aerators only
Aerators only
Chr.nical feed + sludge h<1r!aJ.^ng
Lhc-mical fead + sludge handling
Chsnical fe-d only
Chemical feed only
Ch--icnl feed
Chemical feed
In com- None
pliance
2000 Chemical feed
515
-------
TABLK 134
DASIS FOr, UV.THOFIT COST DLTUilMI^ATION
The following list represents tin additional rc.roval rcquirrnents to be achieved by
existing primary and secondary treatmenr facilities in the bleached kraft sepr.ent.
AIL ASK TRi:Arn-::T I-Y.CILITIES
9 OF Tons/
Mills Day
1
1
4
3
2
2
2
1
2
•^
320
1000
1000
1000
1000
1000
MOO
-, ~ ~ ~
250
1 i1 3 ')
MG!)
6.0
55.0
32.0
32.0
32.0
32.0
32.0
~ ~ -^
7.0
57.0
BOD
I-/ Day
2400
0600
1000
3000
3000
13000
22000
i ~ ~ ^
loon
.:.•< ,U.;
Added Tr
Aerators
Aerators
Aerators
Aerators
Aerators
Aeracors
Aerators
AU. ACTI
,,v,-.,r.ion
! '. ;.- /^i-.;.'
?atri2nt Required
only
+ 3
only
+ 2
-!• A
+ 6
-!- o
VAT;:;;
.1^.1. !•/
days
days
ilays
days
days
PI.Ul
..tct"
rotc.nt .Ion
rs tuition
retention
ri u;nt ion
rr.t^ntion
.
SlrJ;;c
TSS
if /Day
1200
4000
7000
28000
19000
50000
13000
~~ - ~
:::T FACIL
jono
26000
Added Tre
None
Chemical
Clicrilc.-il
Chemical
C.h.or;ical
Clerical
+ Clarifi
Clerical
-.
ITIES
Ch^ir,,!
Choi.iicril
atnent Required
feed
fec-d
fc-cd
feed
f^ed
only
only
+ sludpr.
•f sludge
+ sludfrv!
hanc
In IK
bant
er for 16 I'.GI)
fco.d
-
O.od
i:'.' Ju
+ iillld^.-?
,
for 57 ^
h.in;
j
GD
Lin:1, f.-ir II i I:ICT. ar
Co bo si'-.r.-.l
'.•;vo ;\~t'.'~v U.;i
516
-------
TABLE 135
BASIS FOR RETROFIT COST DETERMINATION
The following list represents the additional removal requirements to be achieved by
existing primary and secondary treatment facilities in the tisane segment.
TISSUE FROM 60% PURCHASED PULP OR MORE
AVG. // OF AVG. BOD TSS
T/D MILLS MGD ///DAY ///DAY ADDED TREATMENT REQUIRED
43 3 2.6 270 270 Chemical feed + full primary system
for 1.3 MGD. Us? clarifiers
160 4 4.3 460 500 Chemical feed + full primary system
for 1.0 MGD. IV- clarificrs
135 3 2.3 475 80 Chemical feed -<- full primary system
TISSUE (fwp-90% WASTE PAPER OR MORE)
25 3 0.4 500 330 Aerator,, •!• 4 dc.yq retention for 0.4 MG>.
NOTE: Added serm.orr,, chenical feed, & a.li'.ilp^ handli;';.; fzzi lit.i^j «ire to b::
for pounds per day of addxcional r<_:-oval r^.qu.'.ciJ . Addici'.c^pl dayn retenti
a>rc to be r.ado for the ".&•)' s Ghev.Ti . Full priT-.:;ry sy.-j-^!:; -,a:Iudes p;:rping
.. . :.
nencs ohown.
517
-------
Table 136
RETROFIT
EFFLUENT TREATMENT COSTS
(All Costs In Thousands Of Dolla:-s)
Mill Size
Retrofit Costs
oo
ns/Day
560
220
'/.•
300
100
600
300
400
320
200
B00r
MGD ///Day
13.0 6200
5.0 6UO
2.0 300
17.0 300
4.0 600
17.0 ll.OOC
12.0 19,000
7.0 8200
6.0 6000
3.0 1000
TSSr
f//Day
4000
None
None
500
None
24,000
24,000
2700
None
30CO
Additional
Investment Cost
Groundwood Segment
1540
50
30
Sulfite Segment
25
45
Soda Segment
3870
4430
Deink Segment
1820
1430
125
Additional
Operating Cost
450
15
10
10
10
1040
1130
435
285
55
Depreciation &
Interest
230
10
5
5
5
580
665
275
215
20
Operatii
Kainten,
220
5
5
5
5
460
465
160
70
35
-------
Table 137
"5TROFIT
EFFLUENT TREATMENT COSTS
(All Costs In Thousands Of Dollars)
Mill Size
Tons /Day
320
1000
1000
1000
Ol
S icoo
1000
1000
1000
250
1230
M^D
6
55
3?
32
32
32
32
32
7
57
EODr
///Day
2'iQO
esco
1000
3000
cOOO
13,000
22,000
36,000
1000
10,000
TSSr
///Day
1200
4000
7000
2800
IS 00
50,000
13,000
9000
3000
26,000
Retrofit Coses
Additional Additional
Investment Cost Operating Cost
Bleached Kraft Segment
150 40
2980 1130
125 345
311q 1050
3930 1170
6570 1730
5410 1470
6250 1630
Bleached Kraft Segment
Waste Activated Sludge
110
6885
227C
ciation &
.terest
25
445
20
470
590
985
810
940
20
1035
Operating &
Maintenance
15
685
325
580
580
745
660
740
75
1235
-------
Table
RETROFIT
EFFLUENT TREATMENT COSTS
(All Costs In Thousands Of Dollsrs)
Ions/Day
375
200
Hill Size
BOD
MGD
2,5
2.0
r
///Day
270
450
TSS-
///Day
Retrofit Costs
Additional
Investment Cost
Additional
Operating Cost
2000
Fine Segment
25 10
85 40
Depreciation &
Interest
5
15
Operating &
Maintenance
5
25
43
160
135
2.6
4.3
2.3
270
460
475
270
500
80
Tissue Segments
630 175
600 165
405 125
95
90
60
80
75
65
25
0.4
330
Tissue (fwp)
520
105
80
25
-------
Table 1.39
UNSURVEYED MILLS ~ REQUIRING RETROFIT
BLEACHED KRAFT SEGMENT
Code ly'D MGU
179 1700 NA
173 1500 24.0
149 1500 42.0
177 1500 35.0
167 1600 38.0
180 1300 20.0
171 920 30.0
161 725 36.0
174 720 29.0
187 640 20.0
Average 1/00 30.0
521
-------
Table HO
RETROFIT CCf/I'S TOR THii BLEACHED KRAFT SEGMENT
Surveys '1 v i 11 r-
Number Cost Per y-vll Total Cost
of Mil.'.s $,1000 1L>_2PJL_
1 150 150
1 2,980 2,980
4 125 500
3 3,115 9,345
2 3,930 7,860
2 6,570 13,140
2 5,410 10,820
2 6,250 6,250
1 110 220
2 6,885 13,770
Unsui'vtv'-cd Mills
Number Cost Per Mill Size Total Cost
of_Mm_s $1,000 Factor $1,000
3 3,115 1.2 11,214
2 3,930 1.2 9,432
2 6,570 1.2 15,768
2 5,410 1.2 12,984
1 6,250 1.2 7,500
TOTAL COST PER SEGMENT 121,933
522
-------
Table 141
RETROFIT COSTS FOR THE TISSUE SEGMEN
Surveyed Mills
Number ^ -erage
of Mills T/D
3
4
3
3
43
160
135
25
Unsurvevcd Mills
Mill
Cojjg
607
609
335
344
339
338
336
348
329
327
612
Aver
T/D
10
20
30
30
30
35
3u
40
50
75
210
Cost Per Mill
$1,000
630
600
405
520
Factor
1
1
1
1
Total Cost
$1,000
1,890
2,400
1,215
1,560
Cost Per Mill
$1,000
630
630
630
630
630
630
630
630
630
630
600
Factor
10/43
20/43
30/43
30/43
30/43
35/43
~r l i n
JU/ ^ J
40/43
50/43
75/43
210/160
Total Cost
$1,000
147
293
440
440
440
513
527
586
735
1,099
788
TOTAL COST PER SEGMENT
13,073
523
-------
should be considered. One potentially viable alternative is
incineration followed by land disposal of the residue (ash).
This section presents capital and operating costs for
incineration systems designed to process waste water sludge
from a dissolving sulfite system. It is reasonable to
assume that sludge dewatering will be optimized prior to
incineration.
To demonstrate the impact of various dewatering systems
costs have been developed for incineration of sludges at a
solids concentration of 20, 30 and 40 percent. As
definitive heat values for the various sludges are
unavailable costs have been developed for sludges at 2220
kg-calories/kg (UOOO BTU/lb), 3330 kg-calories/kg (6000
BTU/lb) and U440 kg-calories/kg (8000 BTU/lb) of dry solids.
It is assumed that the incinerator will be operated 24 hours
per day for five days per week. Three day sludge storage
facilities are included.
The following equipment was used for costing:
One multiple hearth incinerator
Air pollution control equipment
Ash handling equipment
Sludge feed conveyor
Auxiliary fuel system including fuel storage
Fuel and water piping
Controls and instrumentation
Electrical system
Sludge storage tanks, transfer pumps and mixers
Building
Because of high incinerator costs, general practice has been
not to provide a backup incinerator unit. During periods of
extended incinerator downtime, the sludge would normally be
landfilled.
The BTU rating of the sludges must be taken into
consideration when calculating the quantity of auxiliary
fuel that will be required to assist in burning the sludge.
The lower the BTU rating of the dry solids, the greater the
524
-------
quantity of auxiliary fuel will be required. Where the BTU
rating of the dry solids is high enough, the sludge is
autocombustible; i.e., there is sufficient heat value in the
dry solids to sustain combustion without supplying auxiliary
fuel. Generally, where a sludge has a solids content
greater than 30%, and the heat value of the dry solids is
greater than 3,330 kg-calories/kg (6,000 BTU/lb), the sludge
will be autocombustible in a multiple hearth incinerator.
Curves have been developed for the capital cost and
operating costs for various sludge production rates. Figure
92 presents the capital costs for construction of
incinerator the annual operating curves have been present in
Figures 93, 94 and 95 for various percent solids contents
and various BTU ratings of dry solids. Included in these
costs are operation and maintenance, labor, fuel and energy
requirements. Fuel oil is also required as mentioned
previously to supplement combustion when the percent solids
content of the sludge is less than approximately 30%, and/or
the heat value of the dry solids is less than 3330 kg-
calories/kg (6,000 BTU/lb). Electrical energy requirements
for incinerator operation include: incinerator rabble arm
drives, air blowers, ash handling drives, sludge feed
equipment drives, sludge storage tank mixers, transfer
pumps, fuel oil pumping, ventilation blowers, and lighting.
These requirements have been used to develop the energy
curves shown in Figures 96, 97, 98 and 99.
Zinc Removal
The costs developed for Tables 113-129 assume that sodium
hydro-sulfite is used for bleaching. If a mill employs zinc
hydro-sulfite for bleaching or if the zinc discharge from a
mill is in excess of acceptable limitations it may be
necessary to install technology for zinc removal.
Technology discussed previously for zinc removal consists of
a rapid mix pH adjustment structure (two stage), coagulant
addition immediately following pH adjustment, and
flocculatant addition.
Capital and operating costs were determined for the
treatment system described above at three design flows;
18,925 cu m/day (5 mgd) , 56,775 cu m/day (15 mgd) and 94,625
cu m/day (25 mgd). Since primary clarification is BPCTCA
technology it was assumed that it was installed previously.
The capital costs include costs for structures, equipment
and chemical storage facilities. The operating costs
include operation and maintenance labor, chemicals (lime
ferric chloride, and an anionic polymer), and energy
requirements. Figure 100 summarizes the costs for zinc
525
-------
o
3000 -|
2800 -
2600 -
2400 -
g 2200 -
2000 -
O
o
_, 1800 -\
1400 -
1200-
1000 '
800 -
FIGURE 92
SLUDGE INCINERATION
CAPITAL COSTS
COSTS BASED ON 5 DAY
PER WEEK INCINERATION.
Till II
0 5 10 15 20 25 30 (
TONS/DAY OF DRY SOLIDS PRODUCED BY TREATMENT FACILITY
526
-------
SLUDGE INCINERATION
OPERATION & MAINTENANCE COSTS
so n
60 -
O
Q
UJ
o
3
o
o
OL
Q.
O
in
o:
o
u- 40
D
g 20
o
BTU/lb ,>,.TnrnM...cT.P, .
40% SOLIDS CONTENT OF SLUDGE
(I) BTU RATING OF DRY SOLIDS
(2) COSTS BASED ON 5 DAY PER
WEEK INCINERATION
'.3) INCINERATION SELF- SUSTAINING;
MO AUXILIARY FUEL REQUIRED
10
15
20
25
3O
TONS/DAY OF DRY SOLIDS PRODUCED BY TREATMENT FACILITY
(2)
FIGURE 93
-------
SLUDGE INCINERATION
V)
tc
OPERATION & MAINTENANCE COSTS
30% SOLIDS CONTENT OF SLUDGE
en
r
-------
I2O -i
-. 100 -
o
o
S 80
o
a
o
cr
a.
S 60
O
V)
>
o
u. 40
O
o
20 -
SLUDGE INCINERATION
OPERATION & MAINTENANCE COSTS
20% SOLIDS CONTENT OF SLUDGE
(l! BTU RATING OF DRY SOLIDS
(2i COSTS BASED ON 5 DAY PER
WEEK INCINERATION
10
15
20
25
30
TONS/DAY OF DRY SOLIDS PRODUCED BY TREATMENT FACILITY
(2)
FIGURE 95
-------
FIGURE 96
SLUDGE INCINERATION
(t)
ENERGY REQUIREMENTS
O
01
% 900
g 800
600
O
^500
> 400
0 350
O 300
z 250
O
I 200
I 50
100
DGE
2 3 4 5 6 7 8 9 10 15 20 25 30 3540 50 60
TONS/DAY OF DRY SOLIDS PRODUCED BY TREATMENT FACILITY*2'
(I) ELECTRIC ENERGY ONLY
(2) ENERGY REQUIREMENTS BASED ON 5 DAY
PER WEEK INCINERATION
530
-------
FIGURE 97
SLUDGE INCINERATION
(3)
FUEL REQUIREMENTS
40% SOLIDS CONTENT OF SLUDGE
o
UJ
o
D
O
O
cr
Q.
V)
g
_i
o
U)
>-
cr
o
u.
o
z
o
fc
o
_J
-I
UJ
X
UJ
K
3
a
ui
a:
_j
UJ
3
U.
1.2-t
1.0-
0.8-
0.6-
0.4-
0.2-
(I) BTU RATING OF DRY SOLIDS
(2) FUEL REQUIREMENTS BASED ON 5 DAY
PER WEEK INCINERATION
(3) FUEL OIL-ASSUMED 140,000 BTUs/GAL
(4)INCINERATION SELF-SUSTAINING,
NO AUXILLARY FUEL REQUIRED
0
10
15
20
25
30
TONS/DAY OF DRY SOLIDS PRODUCED BY TREATMENT PLANT
(2)
531
-------
FIGURE 98
SLUDGE INCINERATION
(3)
FUEL REQUIREMENTS
4.0 -t
30% SOLIDS CONTENT OF SLUDGE
o
01
o
o
o
o
CE
0.
3.0-
jjOOO BTU/lb
(I)
g
o
i
u.
o
Z
o
»-
N.
2.0-
1.0-
CD
Z
O
V)
»-
Z
ui
Z
ui
o
UI
tt
_l
ui
3
U.
0.8-
0.6-
O.4-
0.0-
0
(I) BTU RATING OF DRY SOLIDS
(2) FUEL REQUIREMENTS BASED ON 5 DAY
PER WEEK INCINERATION
(3) FUEL OIL-ASSUMED 140,000 BTUs/GAL
(4) INCINERATION SELF-SUSTAINING,
NO AUXILLARY FUEL REQUIRED
10
15
20
25
30
TONS/DAY OF DRY SOLIDS PRODUCED BY TREATMENT PLANT
(2]
532
-------
FIGURE 99
SLUDGE INCINERATION
(3)
FUEL REQUIREMENTS
20% SOLIDS CONTENT OF SLUDGE
a
UJ
u
r>
a
o
cc
£L
u.
o
z
o
3
m
z
o
V)
I-
z
UJ
z
UJ
a:
O
UJ
a:
_i
UJ
10-
8-
6-
2-
4000 BTU/lb
(II
,8000 BTU/lb(l)
(I) BTU RATING OF DRY SOLIDS
(3) FUEL REQUIREMENTS BASED ON 5 DAY
PER WEEK INCINERATION
(3) FUEL OIL-ASSUMED 140,000 BTU's/GAL
0 5 10 15 20
TONS/DAY OF DRY SOLIDS PRODUCED BY TREATMENT PLANT
25 30
(2)
533
-------
removal technology. The resultant costs for zinc removal
for the "model" mill sizes are presented in Table 142.
AIR POLLUTION POTENTIAL
There are several potential air pollution problems
associated with the internal and external pollution control
technology used by mills in each of the subcategories
particularly those employing the kraft pulping process.
Most properly designed and operated primary and secondary
waste water treatment facilities from pulp and paper making
operations do not produce odors associated with anaerobic
decomposition. However, it must be noted that odors
associated with anaerobic decomposition are detectable by
the human nose in very small concentrations and do not
necessarily constitute a health or property damage hazard.
Some of these odors are sulfurous in nature while others are
characteristic of wood extractives.
Waste water treatment facilities associated with the kraft
pulping process have the greatest potential for offensive
odor generation. The presence of total reduced sulfur (TRS)
compounds in kraft mill waste waters is generally a result
of the incomplete recovery of spent pulping liquors. The
extent of the liquor losses encountered is a function of,
among others, process operational control practices
employed, uncorrected process design deficiencies, a mill's
production vs. design rate, and the practical efficiency
limitations of the kraft process itself. Specific areas
which are controlled to reduce TRS potential compounds in
kraft mill effluent to treatment include:
1. The brown stock washing process
2. The direct sewering of evaporator condensate and
condensed digester blow tank gases
3. Liquor spills and/or leaks throughout the entire pulping
complex
H. The sulfur content of the process liquors
Once the TRS compound has been entrained in a mill's waste
water, a number of physical, chemical and biological
conditions govern the rate and extent to which these
compounds will be transferred from the waste water to the
surrounding atmosphere. They are:
534
-------
FIGURE 100
ZINC REMOVAL TREATMENT FACILITY COSTS
looocr
loo
FLOW- mgd
535
-------
TABLE 142
ZINC REMOVAL TECHNOLOGY
CAPITAL AND OPERATING COST
Groundwood Subcategory
Model Mill
Capital
Cost
Annual
Fixed
Cost
Annual
Operating
Cost
Total
Annual
Cost
ui
(A)
Chemi-Mechanical
Thermo-Mechanical
Fine
CMN
100 TPD
300 TPD
600 TPD
100 TPD
300 TPD
600 TPD
150 TPD
300 TPD
550 TPD
75 TPD
150 TPD
500 TPD
$113,000
187,000
250,000
93,000
163,000
214,000
125,000
168,000
216,000
89,000
134,000
214,000
$18,600
30,900
41,200
15,300
26,900
35,300
20,600
27,700
35,600
14,700
22,100
35,300
$ 46,000
108,000
173,000
38,000
83,000
144,000
53,000
88,000
142,000
35,000
57,000
139,000
$ 64,900
138,000
214,200
53,300
109,900
179,300
73,600
115,700
177,600
49,000
79,100
174,300
-------
1. The concentration, solubility, degree of ionization and
partial pressure of the specific compounds in typical
kraft mill waste water as well as the temperature, pH,
and dissolved solids concentration of the waste water.
2. The rate of renewal of the air/water interface and the
degree of turbulence that the waste water is subjected
to throughout the entire treatment process.
3. The treatment system detention time and the
bioassimilation capacity of the secondary process for
the TRS potential compounds.
4. The possible bacterial reduction of sulfate to hydrogen
sulfite throughout the entire treatment system.
It should be pointed out that the TRS reduction achieved
inside the mill to reduce the waste water treatment plant
emissions may either induce a different environmental impact
or displace the location of the existing TRS impact. For
example, the removal of TRS compounds from internal process
streams and the subsequent recovery could lead to the
formation of additional particulate and gaseous emissions.
If the mills emission control system is incapable of
handling the additional load, subsequent primary and
secondary impacts associated with the increased mill
discharge could result.
Odors can also result from improper disposal of sludges
resulting from their anaerobic decomposition. These derive
primarily from organic compounds and hydrogen sulfide
produced by reduction of sulfates in the aqueous phase of
the sludges. Optimum dewatering of the sludges prior to
disposal can help this potential problem. The use of good
sanitary landfill practices can also help minimize odors.
Incineration of sludges produced in the waste water
treatment process can eliminate the landfill decomposition
odor problem, but at the same time it can present another
potential air pollution problem, namely the control of
incinerator flue gases. These gases primarily contain
particulate pollutants in them, but with high sulfur content
sludges, sulfur dioxide can also be a problem. Emission
control technology is readily available and has been fully
demonstrated which can be applied to sludge incinerators and
pollutants are commonly reduced to acceptable levels.
537
-------
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, on the basis
of many year's of observation of industry 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, particularly 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 populated areas is usually
neither high-level nor far-carrying.
It can be concluded that noise produced by equipment used
for treating pulp and paper mill effluent is not a major
public problem at present. Efforts underway to reduce the
noise level of mechanical equipment in general stimulated by
industrial health protection programs, will assist in
preventing it from becoming one.
BY-PRODUCT RECOVERY
By-products can be defined as those materials produced by
wood pulping that can be removed from the pulping and/or
chemical recovery process and sold. They do not include
chemicals recovered and reused in the process such as sodium
and sulfur compounds in a kraft operation which are employed
in the preparation of fresh cooking liquor.
538
-------
For the most part, the pulp mill sells the basic material
used in marketable by-products to chemical plants which
manufacture the final products. These are produced either
through purification of the raw materials or by chemical
reaction and separation. If preparation of the raw
materials for shipment from the pulp mill is required, this
operation may contribute a portion of the pulp mill waste
load unless the effluent can be absorbed by the recovery
plant for its chemical or heat value.
By-Products Of Kraft Pulping
Many kraft mills recover two by-products from the pulping
process other than chemicals that are reused — tall oil and
crude turpentine (60) . These materials are present to the
greatest degree in pine species, particularly those common
to the south. They are not usually recovered in mills where
other woods low in these substances are pulped.
Tall oil is a mixture of the resin and fatty acids present
in wood which are saponified during the pulping process and
separated from the black liquor during concentration or
cooling (162). Southern pine species contain approximately
90 to 150 kg (180 to 300 Ib) of this material per kkg (ton)
of air dried pulp produced (60) . It is skimmed from
concentrated black liquor storage tanks in the form of
sodium soap (163) . Some mills convey the soap directly to
tank cars in which it is shipped to chemical plants for use
in manufacturing a number of marketable products including
detergents, adhesives, paints, disinfectants, special oils,
soaps, and plasticizers (164) (163).
Other mills acidulate the soap to produce the oil prior to
shipping. This is generally accomplished by adding 30 to 50
percent sulfuric acid to the soap and separating the oil
from the dregs by decantation or centrifuging. some
acidulation plants operate on a batch and others on a
continuous basis (60) . BODj> and COD values for tall oil are
0.72 and 1.25 kg (1.58 and 2.76 Ib) per kg (Ib) of tall oil,
respectively. The process produces dregs which consist of a
strong solution of sodium sulfate together with precipitated
lignins and other residues of black liquor origin. These
are returned to the pulp mill recovery system in order to
reclaim the chemical and heat values contained therein
(165). Thus, the wastes from tall oil collection,
processing, and shipping are minor in quantity. They
consist of wash water from cleaning floors, equipment, and
loading platforms and are, for the most part, intermittent
in nature.
539
-------
Pine woods contain from 6 to 18 1 of turpentine (1.5 to 4.3
gal.) per kkg (ton) of air dried pulp. The quantity depends
upon the specific wood species pulped, tree age, soil
conditions, seasonal changes, and climatic conditions as
well as the type and length of time of storage (60) (166).
Most of the substance appears in the digester relief
condensate from which it is recovered. The gases leaving
the digester are passed through a cyclone in which black
liquor is separated out for entry into the recovery system.
The steam-turpentine mixture then goes to a surface
condenser, the condensate from which is sent to a storage
tank. There the water and turpentine separate by gravity
and the turpentine is decanted off for storage or shipping
(167). The water fraction is sewered with the other
condensates or, in some instances, disposed of on the land.
Crude turpentine is shipped to chemical plants for
rectification after which it is sold for use as a solvent or
fractionated to separate specific ingredients. Some of
these are used as base compounds in the production of other
chemicals (168), such as dimethyl sulfoxide, an excellent
industrial solvent (169).
Some turpentine remains in the decanted water which joins
the general condensate stream. In some mills anti-
dispersants are used to enhance the separation and thus
reduce the quantity of turpentine lost to the sewer.
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 (168).
On the other hand there are factors which will inhibit
recovery of these 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 (170). Use of more
hardwood, sawmill wastes, immature wood, and outside chip
storage are other adverse factors (163).
Production of other by-products, such as methanol, acetic
acid, tars, etc., from kraft mills on a commercial scale is
not yet economically feasible. Effluent limitations and
540
-------
standards are expected to stimulate increased research on
by-product recovery in the next decade.
By-Products Of Sulfite Pulping
While in recent years the number of sulfite mills producing
and marketing by-products has not increased, eight mills
continue such production and, in some instances, enjoy a
concomitant decrease in waste load (52) (171). Presently
about 10 percent of the spent sulfite liquor produced in
this country is used and there is little indication that
this quantity will increase (172) (173) (174). Sulfite mills
marketing by-products are shown in Table 143.
These by-products derive from the spent pulping liquor and
digester and evaporator condensates. The liquor products
include 1) those which use the whole liquor itself; 2)
products made from the liquor sulfonate fraction, 3) and
those obtained by fermentation of the sugar fraction.
Cymine is separated from the condensates removed from the
digester relief system (3) and formic acid, acetic acid and
furfural are components of the evaporator condensate (179).
The first class of liquor products is made by treating the
raw liquor or evaporating it and bleeding off the
concentrate at various consistencies (40-65 percent) for
sale. The concentrated liquor of ammonia base sulfite mills
can be used directly in tanning (3). Sulfite spent liquor
is also sprayed on gravel roads (road binder) to reduce
dusting (2) (3).
The lignosulfonates are precipitated from raw liquor by the
Howard process (17). These materials can be used as oil
well drilling mud, tanning agents, dispersants, and soil
improvers. The precipitates can be reacted with other
chemicals to produce vanillin and other saleable materials
(175) (172) such as dispersing and emulsifying agents, some
of which are used in dyeing.
Fermentation products include ethanol and torula yeast which
is used as an animal and human food supplement (174). They
are produced from the raw liquor after the free sulfuj:
dioxide has been steam stripped and returned to the acid
plant.
The only major waste produced in the manufacture of spent
sulfite liquor evaporate are the condensates which amount to
about 6260 1 (1500 gals.) for the liquor equivalent of one
kkg (ton) of AD pulp (46). The combined condensates are
acid, free of suspended matter, and, if no appreciable
541
-------
TABLE 143
MILLS MANUFACTURING SPENT SULFITE LIQUOR BY-PROI)UCTS
Mill Code Products
070 F:t Hanoi
Lignin Products
051 Torula Yeast
061 Lignin Products
402 Lignin Products
063 Evaporate
052 Lignin Products
056 Evaporate
066 LignJ.n Products
542
-------
carry-over occurs in the evaporators, low in color. They
contain considerable BOD5 due to the presence of formic and
acetic acids, alcohols, and aldehydes (46).
Preneutralization of the liquor effectively reduces the BOD5_
range from 43 to 75 kg (85 to 150 Ib) per kkg (ton) of AD
pulp to 30 to 35 kg (60 to 70 Ib) (46)(44). It has been
shown that removal of the volatile materials from these
condensates by steam stripping, chemical reaction in the
vapor phase, or by activated carbon can reduce the COD about
75 to 80 percent (49). If the condensate is free of carry-
over, a corresponding reduction in BODJ3 will occur.
However, insufficient markets are available for the formic
and acetic acids that would be produced at the present time.
The lignosulfonates are separated from raw or concentrated
liquor of the following composition:
Percent of
Dry Solids
Lignosulfonic Acid 45-50
Reducing Sugars -
Hexoses 15
Pentoses 12
Other Carbohydrates 15
Inorganics 5
This separation is made by lime precipitation (176) from the
raw liquor or by chemical treatment of evaporate (178).
Effluents from precipitation processes contain the wood
sugars and other carbohydrates responsible for a large
portion of the BODjj of the liquor, and for this reason such
separations reduce the BOD5 waste load only about 20
percent. However, since the precipitate contains most of
the color bodies, the process removes over 80 percent of
this parameter.
There is little data available on specific pollutional
values of the effluents from production of marketable
products from precipitates. This is because such effluents
are not generally segregated and are difficult to relate to
production. However, it has been observed that effluent
from the manufacture of vanillin is very high in color and
susceptible to foaming (172).
Only one mill in the U.S. presently produces ethanol and of
the three that once produced torula yeast only two are in
543
-------
operation. After fermentation the spent beer from both
processes can be evaporated to produce a substantially
sugar-free lignosulfonate solution from which other products
can be made. The condensates produced are lower in BOD5_
than those obtained from raw liquor, ranging from 20 to 25
kg (40 to 50 Ib) per kkg (ton) of AD pulp. Since ethanol
production uses only the hexose sugars, it results in a BOD5_
reduction of less than 25 percent. This reduction is closer
to 50 percent in torula yeast production which uses both
hexose and pentose sugars. Yeast plant effluent ranges from
12,519 to 28,865 1 (3000 to 5000 gal.) for the liquor
equivalents of yeast cells. Generally such effluents
contain from 1500 to 3500 mg/1 of EOD5 and from 250 to 600
mg/1 of total suspended solids.
IMPLEMENTATION REQUIREMENTS
Availability of Equipment
s:ince 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 available
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.
i
Fagure 101 shows graphically past expenditures and projected
future outlays 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 102 shows past expenditures and projected future
trends in total sales of waste water treatment equipment and
the dollar amounts attributable to industrial and municipal
544
-------
Ul
**
Ul
m
1966
1980
YEAR
FIGURE 101
TOTAL WATER POLLUTION
CONTROL EXPENDITURES
-------
en
1966
74
76
78
1980
YEAR
FIGURE 102
WASTE WATER TREATMENT
EQUIPMENT SALES
-------
sales. This curve closely follows the trend shown in Figure
101.
The data in Figures 101 and 102 related to industrial water
pollution expenditures include only those costs external to
the industrial activity. 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 demand for equipment has been lower than
anticipated. Production capacity has increased assuming
Federal expenditures in accord with funds authorized by
Congress and conformance to compliance schedules.
For the immediate future, increased demands for waste water
treatment equipment can be absorbed by the existing
overcapacity. Long term requirements will probably
necessitate expansion of production capacity in various
product lines where the demand is expected to increase
dramatically — specifically, advanced treatment systems and
waste solids handling equipment.
It should also be noted that the capacity to produce waste
water treatment equipment could be expanded significantly
through the use of independent 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
geographical limitation. The use of independent metal
fabricators as subcontractors to manufacture certain pieces
of equipment further reduced 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.
547
-------
Availability of Construction Manpower
After consultation with the Associated General Contractors
of America and other industry groups, it has been concluded
that sufficient manpower exists to construct any required
treatment facilities. The Bureau of Labor Statistics has
been requested to conduct another study.
Construction cost Index
The most detailed study and careful analysis of cost trends
in prior years still leave much to be desired in predicting
construction costs through the next ten years.
During the years 1955 through 1965 there was a very
consistent price rise. The Engineering News Record(ENR)
Construction Cost Index in January 1955 was 644. With
slight deviations from a straight line, costs rose at a
steady rate to an index of 988 in December 1965. This
represented an increased cost of 53.4 percent over an 11
year period of approximately five percent per year.
The first six months of 1966 saw an increase of 6.6 percent
then leveled off abruptly only to rise sharply again in 1967
at a rate of 6.2 percent, then increasing to 9.4 percent in
1968.
The increase in costs continued to rise at about 10.5
percent per year through 1970. During 1971, construction
costs rose at the unprecedented rate of 15.7 percent
primarily due to larger increases in labor rates.
With the application of federal wage and price controls in
1972, the rate of increase dropped to 8.6 percent for the
year and continued at the same rate during the first six
months of 1973. The cost index curve began to level off
during the latter part of 1973 resulting in an increase of
6.8 percent for the year.
Cost predictions for extension of ENR Cost Index are
confused at this time. ENR in the 1974 first Quarterly Cost
Roundup (March 21, 1974) stated, "Predicting cost trends is
always difficult, but this year contractors face what is
perhaps the most bewildering period in a quarter century."
The strong inflationary forces now facing the United States
and the rest of the world are the worst hazard to cost
predictions. With what has previously been considered a
normal rate of inflation, it could be anticipated that
548
-------
expansion of industrial capacity would help to level off
current sharp price increases.
The long range outlook for the Construction Cost Index would
seem to be close to an annual increase of 8 percent, the
basis on which Figure 103 was drawn. This has been
confirmed by recent escalation rates. Developments in the
industry may require adjustments up or down from the
projected cost index for current program costs in any
particular year.
Land Requirements
In assessing a mills effluent treatment system, land
requirements are oftentimes critical. Many mills are
located remote from population centers, thus oftentimes land
is available for construction of treatment systems requiring
large areas. However, on the contrary many mills are
severely land limited. Often a mill must construct a
treatment facility requiring minimal land or they must
transport their waste waters many miles to available land.
The land requirements for a number of effluent treatment
facilities have been evaluated and are shown in Figure 104.
For comparative purposes the lands requirements have been
estimated for two subcategories, BCT Kraft and Papergrade
Sulfite - Blow pit. It is anticipated that one would be
hydraulically controlled while organic loading would control
the other subcategory. In addition, the impact of land
requirements of installing one versus two clarifiers is
presented. The land areas presented in this figure are
minimums, as compact unit process arrangements are assumed.
Also offsite disposal of dewatered sludge has been assumed.
Should sludge lagoons be used on-site, additional land would
be required. Actual land requirements for sludge lagoons
varies with storage volumes and sludge production. It
should be noted that the costs for land have been excluded
in the costs presented previously.
Time Required to Construct Treatment Facilities
The time required to construct primary and secondary
effluent treatment facilities has been estimated for a range
of plant sizes and for two different project contract
possibilities. The treatment plant sizes evaluated were
under 5 MGD, 5 to 20 MGD, and over 50 MGD. The contract
possibilities evaluated were for the engineering and
construction to be separate or on a turnkey basis.
549
-------
3800
3400
3000
o 2600
o
tL
(-
z
o
o
2200
1800
1400
1000
600
FIGURE 103
ENGINEERING NEWS RECORD
CONSTRUCTION COST INDEX
MA'
19
TCBE
2478
1976
T\
JU
.Y
19
97
*V
JU
.Y 1977
2650
1955
I960
1965
1970
1973 1975 1977
YEAR
550
-------
FIGURE 104
MINIMUM LAND REQUIREMENTS
EFFLUENT TREATMENT FACILITIES
/AERATED STABILIZATION
ACTIVATED SLUDGE
PRIMARY
CLARIFICATION
(ONE VERSUS TWO
CLARIFIERS)
3 4 S6789IO
20 30 40 SO 60 80 IOO
FLOW - MGD
* SLUDGE IS LANDFILLED OFF SITE
551
-------
Effective utilization of "turnkey" construction procedures
reduces the overall time requirements from conception to
start-up of an effluent treatment facility. If a mill was
under regulatory deadlines, it is anticipated that the
overall construction time might be reduced even more than
that shown in Figure 105 by carefully expediting the many
construction sub-contracts.
A small mill with relatively small effluent volume (See
Figure 105) could have its primary and secondary treatment
facilities in operation in less than 2.5 years if the
contract was handled on a turnkey basis. The majority of
the effluent treatment facilities handled with separate
engineering and construction contracts, plus the medium and
large mills handled with effective turnkey procedures, would
be completed in 2.5 to 4.5 years, assuming no external
treatment facilities were in place. If some treatment
facilities are existing, the construction time can be
shortened.
552
-------
Ul
U1
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SIZE
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CONV.
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TURNKEY
5-20
CONV.
5-20
TURNKEY
20-50
CONV.
20-50
TURNKEY
OVER 50
CONV.
OVER 50
TURNKEY
YEAR , YEAR 2
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1 PRELIMINARY ENGINEERING
FINAL DESIGN ENGINEERING p ,_,.
BID AND CONSTRUCTION AWARD
CONSTRUCTION TIHE REQUIRED TO
OMSTWCTI0" CONSTRUCT HASTEHATER FACILIT
CONVENTIONAL AND TURNKEY CONTR
J J * S 0 N D
i
I
-
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IES
ACTS
-------
-------
SECTION IX
BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY AVAILABLE (BPCTCA)
INTRODUCTION
The effluent limitations which must be achieved by July 1,
1977, specify the degree of effluent reduction attainable
through the application of the BPCTCA, which is generally
based upon the average of the best existing performance by
plants within the industrial subcategories as discussed in
detail below. In addition to the factors mentioned above,
consideration was given to:
a. the total cost of application of technology in
relation to the effluent reduction benefits to be
achieved from such application, including energy
requirements;
b. the engineering aspects of the application of
various types of control techniques;
c. the size and age of mills;
d. process changes;
e. non-water quality environmental impact.
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 or common practice within an industry.
A further consideration is the degree of economic
feasibility and engineering 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 facilities.
555
-------
EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION OF
BPCTCA
Based upon the information available to the Agency, a
determination has been made that the point source discharge
limitations for each identified pollutant, as shown in Table
144, can be attained through the application of the Best
Practicable Pollution Control Technology Currently
Available.
The average of daily values for 30 consective days should
not exceed the maximum 30 day average limitations shown.
The value for one day should not exceed the daily maximum
limitations shown in this table. The limitations shown are
in kilograms of pollutant per metric ton of production
(pounds of pollutant per ton of production). Effluents
should always be within the pH range of 5.0 to 9.0.
Production shall be defined as the annual off-the-machine
production (including off-the-machine coating where
applicable) divided by the number of operating days during
that year. Paper production shall be measured in the off-
the-machine moisture content whereas market pulp shall be
measured in air-dry-tons (10X moisture). Production shall
be determined for each mill based upon past production
practices, present trends, or committed growth.
Allowances for Wet Woodyard Operations
The discussion in Section V pointed out three primary
woodyard operations from which waste waters are generated:
(1) wet barking operations, (2) log and chip washing/thawing
operations, and (3) flumes and ponds for log transport and
defreezing. Wet barking operations shall be defined to
include hydraulic barking operations and wet drum barking
operations which are those drum barking operations that use
substantial quantities of water in either water sprays in
the barking drums or in a partial submersion of the drums in
a "tub" of water. Raw waste loads generated by these
operations are shown in Table 40 in Section V and the
additional allowances for mills using the operations are
shown in Tables 2, 3 and 4, respectively, in Section II.
The allowances shown in Tables 2, 3 and 4 may be added to
the effluent limitations in Table 144 and shall be
calculated using the proportion of the mill's total
production due to the use of logs and/or chips which are
subject to such operations.
The woodyard allowances were determined by adding the raw
waste load associated with the specific woodyard operation
556
-------
TflRT.B £44
BPCTCA
EFFLUENT LIMITATIONS IN KG/KKG(lbs/ton)
Subcategory
Dissolving Kraft
Market Kraft
BCT Kraft
Fine Kraft
BODS
12.25 (24.5)
8.05 (16.1)
7.1 (14.2)
5.5 (11.0)
TSS
20.05 (40.1)
16.4 (32.8)
12.9 (25.8)
11.9 (23.8)
Paper-grade Sulfite (Blow Pit Wash)
Bisulfite-Surface
Bisulfite-Barcmetric
Acid Sulfite Surface
Acid Sulfite-Barometric
16.55 (33.1)
18.05 (36.1)
16.8 (33.6)
18.5 (37.0)
23.65 (47.3)
28.1 (56.2)
23.65 (47.3)
28.1 (56.2)
Papergrade Sulfite (Drum Wash)
Bisulfite-Surface
Bisulfite-Barcmetric
Acid Sulf ite-Surface
Acid Sulf ite-Barcmetric
Continuous Digesters
Dissolving Sulfite
Nitration
Viscose
Cellophane
Acetate
GW-Chemi-Mechanical
GW-Thernio-Mechanical
GW-CMN Papers
GW-Fine Papers
Soda
Deink
NI Fine Papers
NI Tissue Papers
NI Tissue Papers (FNP)
13.9 (27.8)
15.3 (30.6)
15.5 (31.0)
16.9 (33.8)
19.85 (39.7)
21.55 (43.1)
23.05 (46.1)
25.0 (50.0)
26.45 (52.9)
7.05 (14.1)
5.55 (11.1)
3.9 ( 7.8)
3.6 ( 7.2)
7.1 (14.2)
9.4 (18.8)
4.25 ( 8.5)
6.25 (12.5)
7.1 (14.2)
23.65 (47.3)
28.1 (56.2)
23.65 (47.3)
28.1 (56.2)
28.95 (57.9)
38.05 (76.1)
38.05 (76.1)
38.05 (76.1)
38.05 (76.1)
10.65 (21.3)
8.35 (16.7)
6.85 (13.7)
6.3 (12.6)
13.2 (26.4)
12.95 (25.9)
5.9 (11.8)
5.0 (10.0)
9.2 (18.4)
pH for all subcategories shall be within the range of 5.0 to 9.0
Subcategory
GW-Chani-iytechanical
Q^-Therno-Mechanical
Qtf-cm Papers
GW-Fine Papers
Zinc*
Maximum 30-Day Average
0.17 (0.34)
0.13 (0.26)
0.15 (0.30)
0.135 (0.27)
Maximum Day
BODS
23.6 (47.2)
15.45(30.9)
13.65(27.3)
10.6 (21.2)
31.8 (63.6)
34.7 (69.4)
32.3 (64.6)
35.55(71.1)
26.7 (53.4)
29.4 (58.8)
29.75(59.5)
32.5 (65.0)
38.15(76.3)
41.4 (82.8)
44.3 (88.6)
48.05(96.1)
50.8 (101.6)
13.5 (27.0)
10.6 (21.2)
7.45(14.9)
6.85(13.7)
13.7 (27.4)
18.1 (36.2)
8.2 (16.4)
11.4 (22.8)
13.7 (27.4)
9.0
Maximum Day
0.34 (0.68)
0.26 (0.52)
0.30 (0.60)
0.275(0.55)
TSS
37.3 (74.6)
30.4 (60.8)
24.0 (48.0)
22.15(44.3)
43.95(87.9)
52.2 (104.4)
43.95(87.9)
52.2 (104.4)
43.95(87.9)
52.2 (104.4)
43.95(87.9)
522 (104.4)
53.75(107.5)
70.65(141.3)
70.65(141.3)
70.65(141.3)
70.65(141.3)
19.75(39.5)
15.55(31.1)
12.75(25.5)
11.75(23.5)
24.5 (49.0)
24.05(48.1)
11.0 (22.0)
10.25(20.5)
17.05(34.1)
*Applicable only to mills using zinc hydrosulfite
557
-------
(as determined in Section V) for the specific subcategory to
each respective subcategory total raw waste load as shown in
Table 16 in Section IV. Using the revised raw waste load,
the raw waste BOD5_ concentration was determined and used in
the relationships shown in Section VII relating biological
treatment influent and effluent BOD_5 concentrations. The
BOD5_ allowance was then determined using the predicted BOD5_
effluent concentration, the revised raw waste flow, and the
variability factors shown in Table 148. For the sulfite
subcategories, the relationship was the following:
Log BOD5_ Eff = 0.496 Log BOD5 Inf + 0.309
For the bleached kraft, groundwood, and soda subcategories,
the following relationship was used:
Log BOD5_ Eff = 0.601 Log BODS^ Inf - 0.020
As pointed out in the determination of raw waste loads for
the dissolving sulfite subcategory, the flow from wet
woodyard operations was already included in the subcategory
raw waste flow average and therefore only the BODS^ from the
woodyard operations was used in determining the allowances.
A number of the allowances shown in Tables 3 and 4 for log
and chip washing/thawing and for log flumes and ponds,
respectively, were rounded up to 0.05 kg/kkg (0.1 Ibs/ton)
and therefore, the values in the tables may appear
inconsistent in several cases.
The TSS allowances were determined using the revised flow
for each subcategory and the TSS concentrations shown in
Table 149 which were the basis for the TSS effluent
limitations.
Effluent Limitations for Non-Continuous Dischargers
Table 145 presents annual average effluent limitations in
kg/kkg (Ibs/ton) and average of 30 consecutive days and
maximum day effluent limitations in concentrations for non-
continuous dischargers. The average of 30 consecutive days
and maximum day limitations were developed using the annual
average limitations and the variability factors presented in
Table 146. The development of the variability factors is
discussed in Section VII. A non-continuous discharger is a
mill which is prohibited by the NPDES authority from
discharging pollutants during specific periods of time for
reasons other than treatment plant upset control, such
periods being at least 24 hours in duration. A mill shall
not be deemed a non-continuous discharger unless its NPDES
permit, in addition to setting forth the prohibition
558
-------
TftBUE 145
BPCTCA
EEFUJENT LIMITATIONS TOR NQN-COOTINUOUS DISCHARGERS
Subcategory
Dissolving Kraft
Market Kraft
BCT Kraft
Fine Kraft
Papergrade Sulfite (Blow Pit Wash)
Bisulfite-Surface
Bisulfite-Barcmetric
Acid Sulfite-Surface
Acid Sulfite-Baroroetric
Papergrade Sulfite (Drum Wash)
Bisulfite-Surface
Bisulfite-Baronetric
Acid Sulfite-Surface
Acid Sulfite-Barcmetric
Continuous Digesters
Dissolving Sulfite
Nitration
Viscose
Cellophane
Acetate
OT-Chemi-Mechanical
OJ-lhermD-Mechanical
Q*-CMN Papers
GW-Fine Papers
Soda
Deink
NI Fine Papers
NI Tissue Papers
NI Tissue Papers (FWP)
Annual Average
kg/kkg (Ibs/ton)
BCD5
6.
4.
4.
3.
9,
10.
9.
10.
7.
8.
8.
9.
11.
12,
12.
14.
14.
3.
3.
2.
2.
4.
5.
2.
3.
4.
9
5
0
1
3
15
45
4
8
6
7
5
15
1
95
05
85
95
1
2
0
0
3
4
5
0
(13
( 9
( 8
( 6
(18
(20
(18
(20
(15
(17
(17
(19
(22
(24
(25
(28
(29
( 7
( 6
( 4
( 4
( 8
(10
( 4
( 7
( 8
.8)
.0)
.0}
.2)
.6}
.3)
.9)
.8)
.6)
.2)
.4)
.0)
.3)
.2)
.9)
.1)
.7)
.9)
.2)
.4)
.0)
.0)
.6)
.8)
.0)
.0)
11.
9.
7.
6.
13.
15.
13.
15.
13.
15.
13.
15.
15.
20.
20.
20.
20.
5.
4.
3.
3.
7.
7.
3.
2.
5.
TSS
05
0
1
55
0
45
0
45
0
45
0
45
9
9
9
9
9
85
6
75
45
25
1
25
85
05
(22
(18
(14
(13
(26
(30
(26
(30
(26
(30
(26
(30
(31
(41
(41
(41
(41
.1)
.0)
.2)
.1)
.0)
.9)
.0)
.9)
.0)
.9)
.0)
.9)
.8)
.8)
.8)
.8)
.8)
(11-7)
( 9
( 7
( 6
(14
(14
( 6
( 5
(10
.2)
.5)
.9)
.5)
.2)
.5)
.75
.1)
Maximum 30 Day Average
mg/l.
Maximum Day
BODS
56
48
50
45
93
86
95
87
78
73
87
80
91
82
87
95
100
165
65
41
41
52
97
71
69
71
TSS
86
94
86
92
126
126
126
126
126
126
126
126
126
137
137
137
137
94
94
68
68
92
126
92
54
86
BODS
98
84
88
78
162
150
166
153
136
127
153
140
159
143
153
166
176
114
114
72
72
91
169
124
120
124
TSS
168
182
168
178
245
245
245
245
245
245
245
245
245
266
266
266
266
182
182
133
133
178
245
178
105
168
-------
TABLE 145(Cont.)
ALLOWANCES (ANNUAL AVERAGE)
cri
o
Subcategory
Dissolving Kraft
Market Kraft
BCT Kraft
Fine Kraft
Paper-grade Sulf ite (Blow Pit Wash)
Bisulfite-Surface
Bisulfite-Baronetric
Acid Sulfite-Surface
Acid Sulfite-Baronetric
Papergrade Sulfite (Drum Wash)
Bisulfite-Surface
Bisulfite-Baronetric
Acid Sulfite-Surface
Acid Sulfite-Barometric
Continuous Digesters
Dissolving Sulfite
Nitration
Viscose
Cellophane
Acetate
GW-Chemi-Mechan ica1
GW-Ttiermo-Mechanical
GW-CMN Papers
GW-Fine Papers
Soda
Wet Barking
kg/kkg (Ibs/ton)
BODS
0.95
0.7
0.65
0.55
0.8
0.8
0.8
0.8
0.9
0.9
0.9
0.9
0.9
0.2
0.2
0.2
0.2
0.25
0.3
0.3
0.35
0.6
(1.9)
(1.4)
(1.3)
(1.1)
(1.6)
(1.6)
(1.6)
(1.6)
(1.8)
(1.8)
(1.8)
(1.8)
(1.8)
(0.4)
(0.4)
(0.4)
(0.4)
(0.5)
(0.6)
(0.6)
(0.7)
(1.2)
TSS
2.0
1.55
1.7
1.55
2.2
2.2
2.2
2.2
2.2
2.2
2.2
2.2
2.2
0.05
0.05
0.05
0.05
0.8
0.75
0.6
0.6
1.55
(4.0)
(3.1)
(3.4)
(3.1)
(4.4)
(4.4)
(4.4)
(4.4)
(4.4)
(4.4)
(4.4)
(4.4)
(4.4)
(0.1)
(0.1)
(0.1)
(0.1)
(1.6)
(1.5)
(1.2)
(1.2)
(3.1)
log or Chip Washing
kg/kkg (Ibs/ton)
BODS
0.1
0.1
0.05
0.05
0.05
0.05
0.05
0.05
0.1
0.1
0.1
0.1
0.1
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
(0.2)
(0.2)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.2)
(0.2)
(0.2)
(0.2)
(0.2)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
IBS
0.2
0.15
0.2
0.15
0.75
0.75
0.75
0.75
0.75
0.75
0.75
0.75
0.75
0.05
0.05
0.05
0.05
0.1
0.05
0.1
0.1
0.15
(0.4)
(0.3)
(0.4)
(0.3)
(1.5)
(1.5)
(1.5)
(1.5)
(1.5)
(1.5)
(1.5)
(1.5)
(1.5)
(0.1)
(0.1)
(0.1)
(0.1)
(0.2)
(0.1)
(0.2)
(0.2)
(0.3)
Log Flumes or Ponds
kg/kkg (Ibs/ton)
BODS
0.2
0.15
0.1
0.1
0.1
0.1
0.1
0.1
0.2
0.2
0.2
0.2
0.2
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.1
(0.4)
(0.3)
(0.2)
(0.2)
(0.2)
(0.2)
(0.2)
(0.2)
(0.4)
(0.4)
(0.4)
(0.4)
(0.4)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.1)
(0.2)
TSS
0.4
0.35
0.35
0.3
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.05
0.05
0.05
0.05
0.15
0.15
0.15
0.15
0.35
(0.8)
(0.7)
(0.7)
(0.6)
(1.0)
(1.0)
(1.0)
(1.0)
(1.0)
(1.0)
(1.0)
(1.0)
(1.0)
(0.1)
(0.1)
(0.1)
(0.1)
(0.3)
(0.3)
(0.3)
(0.3)
(0.7)
-------
145 (Cont.)
ZINC
Annual Average
Subcategory kg/kkg (Ibs/ton)
(3«J-Cherai-Mechanical 0.115 (0.23)
GW-Ilienno-ffechanical 0.085 (0.17)
GW-CMN Papers 0.10 (0.20)
GW-Fine Papers 0.09 (0.18)
561
-------
TABLE
VARIABILITY FACTORS FOR
NON-CONTINUOUS DISCHARGERS
Parameter Haximum 30 Days MaximumDay
BQD5_ 1.86 3.25
TSS 1.80 3.50
562
-------
described above, requires compliance with the annual average
limitations shown in Table 145 and also requires compliance
with maximum day and average of 30 consecutive day effluent
limitations. The maximum day and average of 30 consecutive
day effluent limitations shall be in the form of
concentrations which reflect waste water treatment levels
that are representative of application of best practicable
control technology currently available.
In addition to the annual averages specified in Table 145,
the allowances (i.e., woodyard, type of sulfite cooking
liquor) provided in a number of subcategories are specified
in terms of annual average and can be added to the annual
average limitations for non-continuous dischargers. It
should be pointed out that some variation in the average of
30 consecutive day and maximum day effluent limitations
shown in Table 145 may be justified if a mill is achieving
the annual average effluent limitations in kg/kkg (Ibs/ton)
with an average raw waste flow which is less than the
subcategory average flow shown in Table 1U9. In this case,
the concentrations shown in Table 145 could be adjusted
correspondingly. It is suggested that variations from those
concentrations set forth in Table 145 be adjusted by the
following formula:
C = L x SF
MF
C = BOD5 or TSS concentration
L = BODj> or TSS concentration shown
in Table 145 for appropriate subcategory
MF = Mill flow (annual average)
SF = Subcategory flow shown in Table 149
IDENTIFICATION OF BEST PRACTICABLE CONTROL TECHNOLOGY
CURRENTLY AVAILABLE
Best Practicable Control Technology Currently Available
varies among the subcategories. The selected external
technology suggested as BPCTCA and the internal technologies
employed by the mills in each subcategory are discussed in
detail in Section VII and VIII.
It is emphasized here that these technologies are not of
themselves required. Due to economic, space, or other
factors, many mills may choose to use alternative
technologies. Conversely, some mills may choose
technologies in addition to those shown. For example,
biological treatment is not included for mills in the non-
integrated tissue subcategory. The reason is that many of
563
-------
these mills with only primary treatment have achieved equal
or better results than some others which also use biological
treatment. A specific mill within these subcategories may,
howeven, choose biological treatment as the most effective
method of meeting the limitations.
RATIONALE FOR THE SELECTION OF BEST PRACTICABLE 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 subcategories studied. However, internal operations of
most older mills have been upgraded, and most of these mills
currently operate very efficiently. The technology for
upgrading of older mills is well known within a given
subcategory. Studies have also shown that waste treatment
plant performance does not relate to mill size. There is no
significant variation in either the waste water
characteristics or in the waste water loading rates, in
kg/kkg (Ib/ton) , among mills of varying sizes. Figures are
presented in Section IV showing the insignificant
relationships between raw waste load and mill size.
Processes Employed
All mills within each subcategory studied use the same basic
production processes. Although there are deviations in
equipment and production procedures, these deviations do not
significantly alter the characteristics of the waste water
generated within each subcategory. Treatability of these
wastes is similar.
Application of best practicable control technology currently
available does not require major changes in existing
industrial processes for the sufccategories studied.
Incorporation of additional systems, treatment processes,
and control measures can be accomplished in most cases
through changes in piping, and through modifications of
existing equipment. Such alterations can be carried out at
mills within a given subcategory.
The technology to achieve these effluent limitations is
practiced within the subcategories under study. The
concepts are proven, available for implementation, and
applicable to the wastes in question. The waste treatment
techniques are also broadly applied within many other indus-
tries. The technology required will necessitate improved
monitoring of waste discharges and of waste treatment
564
-------
components on the part of many mills, and may require more
extensive training of personnel in the operation and
maintenance of waste treatment facilities. However, these
procedures are currently practiced in many mills and are
common practice in many other industries.
Non-Water Quality Environmental Impact
The technology cited will not create any significant
increase in odors, or in noise levels beyond those observed
in well-designed municipal waste water 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.
Cost of Application in Relation to Effluent Reduction
Benefits (Including Energy Requirements)
The total project costs of BPCTCA reflect an increase of
production expenses as shown in Tables 113 through 129 of
Section VIII. These increases reflect both all internal
mill and external waste treatment improvements. They are
based on 360 days of production per 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. The energy
requirements associated with the application of pollution
control technologies are described in Section VIII. The
total estimated cost of BPCTCA for all of the mills is $2.3
billion with associated total effluent reduction of
approximately 4,535 kkg (5,000 tons) per day of BOD5. Table
147 presents costs per kg (Ib) of BOD5 removed for each of
the subcategories.
RATIONALE FOR SELECTION OF EFFLUENT LIMITATIONS
The rationale used in developing the effluent limitations
for BOD5, TSS, and zinc (groundwood subcategories only), is
discussed below for each of the subcategories. Specifically
identified are the methods used to select the limitations
for the maximum 30 consecutive day average and the daily
maximum value for BOD5_ and TSS. To the extent possible, the
effluent limitations for both parameters are based on 12 to
24 months of data obtained from nearly 200 mills. The
procedure for selecting the mills in each subcategory whose
external pollution control facilities demonstrate a high
level of performance is also described in this section.
The development of the effluent limitations for each
subcategory are discussed in detail in the following
565
-------
TABLE 147
COSTS OF BPCTCA VS. EFFLUENT REDUCTION BENEFITS
Annual Costs
Sufacategory $ Millions $/1b BQD5 Removed
Dissolving Kraft 5.6 0,13
Market Kraft 3.4 0.20
BCT Kraft 5.5 0.17
Fine Kraft 5.1 0.18
Papergrade Sulfite
(Blow Pit Wash) 6.9 0.16
Papergrade Sulfite
(Drum Wash) 6.7 0.19
Dissolving Sulfite 7.7 0,10
GW-Chemi-Hechanical 3.3 0.08
GW-Thermo-Mechanical 2.2 0.14
GW-CMN Papers 1.9 0.33
GW-Fine papers 1.9 0.31
Soda 4.0 0.20
Deink 3.5 0.11
HI Fine Papers* 1.0 0.63
NI Tissue Papers* 1.2 0.51
NI Tissue Papers (FWP)* 1.7 0.55
*Production days per year: 330 days; all others: 360 days
Note: Costs were from cost tables in Section VIII and were
determined using ASB costs and the largest mill size
in the tables.
566
-------
paragraphs. The basic approach used in determining the
effluent limitations involved the following: (1) the
establishment of raw waste loads for each subcategory (see
Section V); (2) determination of external treatment
performance of the external treatment facilities at mills
within each of the subcategories (See Section VII). Where
the available data permitted, the performance was measured
by the absolute values of the quality of the effluents from
the external treatment facilities. Where data were not
available, data were incomplete, or the treatment facilities
were inadequate for mills within a subcategory, performance
was based upon similar subcategories using similar treatment
technologies and treating similar waste waters, as discussed
in detail below); and (3) establishment of the effluent
limitations using the raw waste loads and external treatment
performance as identified in the above efforts.
Specifically, the average effluent flow volume as determined
for each subcategory in Section V was used with the
appropriate BOD5. and TSS concentrations which were
determined through analysis of the relationship between
influent BODj> and effluent BOD5 and TSS concentrations as
presently being achieved by mills using well designed and
properly operated treatment facilities representative of
BPCTCA. The waste water flow (as well as the raw waste
BOD5) indicates the extent of inplant control measures in
use at mills within the subcategories, and use of the
average flow per subcategory in developing the effluent
limitations therefore reflects a level of inplant waste
water management technologies which are commonly practiced.
By using the average flow for each sufccategory, mills using
a normal level of inplant control measures and well designed
and operated external treatment will be able to achieve the
effluent limitations through the use of BPCTCA. It should
be pointed out that the flow, BODS^ and TSS raw waste loads
that were developed in Section V were also used in the
development of the costs in Section VIII.
The determination of the BODji and TSS concentrations
involved thorough evaluations of the external treatment
systems at mills within each of the subcategories. In
several cases, mills achieved high quality BODj>
concentrations in their effluents while the TSS
concentrations were very poor. In nearly every case, the
poor performance on TSS can be related directly to poor
design and operation of the facilities (i.e. the design was
based solely on BOD5 removal without regard to TSS removal).
The effluent limitations were developed on an annual average
basis and then multiplied by the variability factors
developed in Section VII to determine the maximum 30
567
-------
consecutive day and maximum day limitations. The
variability factors used in determining the effluent
limitations are shown in Table 148. The flow values
developed in Section V were based upon 12 to 2U months of
daily data or more when available. In addition, the final
effluent concentrations represent averages of 12 to 2U
months or more of daily data for the same data periods as
the raw waste load data for each mill. Table 149 presents
the flow, BOD5, and TSS values and the corresponding annual
average BOD5 and TSS values which were used as the basis of
the effluent limitations for each of the respective
subcategorres. It should again be emphasized that mill
sampling, flow measurement, and laboratory analytical
techniques were thoroughly evaluated to assure that the mill
data used in the development of the effluent limitations
were valid. Because of this, some mill data were eliminated
from consideration due to various deficiencies. For
instance, a number of mills measure TSS by non-standard
methods using a paper filter rather than by the standard
procedure of using a glass fiber filter. The two analytical
procedures yield widely different results and no correlation
exists between the two tests. TSS data as measured by non-
standard methods were thereby not used in determining
effluent limitations. In addition, the operating procedures
of the treatment facilities in use by the best mills were
examined to determine the adequacy of operation and the
impact upon final effluent characteristics. For those mills
with adequate designed treatment facilities representative
of BPCTCA and inadequate operating procedures during all or
part of the time (i.e. shutting down aerators during winter
months), the data representing the inadequate operations
were not used in determining the effluent limitations.
The achievability of the effluent limitations was examined
and it was determined that a large number of mills presently
comply with the effluent limitations. Compliance with the
effluent limitations was examined for mills for which
adequate data (one year) were available and for a mill to be
considered in compliance, the mill data did not exceed any
of the four limitations ( (1) maximum 30 day BOD5>, (2)
maximum daily BODjS, (3) maximum 30 day TSS, and (4) maximum
daily TSS) within the year of data. A number of mills were
determined to be in non-compliance with the effluent
limitations but this does not necessarily mean that those
mills will have difficulty in achieving the effluent
limitations. Exceeding any one of the four limitations for
one day or one month was counted as non-compliance and in
many cases, the excursions in the data were determined to be
the result of such items as sampling or analysis or
operating problems (i.e., power outage, aerators failure).
568
-------
Table 148
BPCTCA Variability Factors
Bleached Kraft Soda, Groundwood, Sulfite, Deink,
NI Fine Papers, and NI Tissue (fwp) Subcategories
Parameter Maximum 30 Days Maximum Day
BOD5_ 1.78 3.42
TSS 1.82 3.38
NI Tissue Papers Subcategory
Parameter Maximum 30 Days Maximum Day
BOD5_ 1.79 3.25
TSS 1.76 3.60
569
-------
TABLE
BASIS TOR BPCICA EFFLUENT LIMITATIONS
Subcategory
Dissolving Kraft
Market Kraft
BCT Kraft
Fins Kraft
Papergrade Sulfite (Blow Pit Wash)
Bisulfite-Surfaoe
Bisul f i te-Baronetric
Acid Sulfite-Surfaoe
Acid Sulfite-Barometric
Papergrade Sulfite (Dnm Wash)
Bis ulfite-Sur face
Bisulfite-Baremetric
Acid Sulfite-Surfaoe
Acid Sulfite-Baronetric
Continuous Digesters
Dissolving Sulfite
Nitration
Viscose
Cellophane
Acetate
GW-Chemi-Mechanical
GW-Thermo-Mechanical
CSf-CMN Papers
W-Fine Papers
Soda
Deink
NI Fine Papers
NI Tissue Papers
NI Tissue Papers (FWP)
Flow
kl/kkg (kgaI/ton)
230
173
148
129
186
221
186
221
186
221
186
221
227
275
275
275
275
113
88
99
91
142
102
63
96
105
(55.1)
(41.6)
(35.4)
(30.9)
(44.5)
(53.0)
(44.5)
(53.0)
(44.5)
(53.0)
(44.5)
(53.0)
(54.5)
(66.0)
(66.0)
(66.0)
(66.0)
(27.0)
(21.1)
(23.8)
(21.9)
(34.1)
(24.4)
(15.2)
(22.9)
(25.2)
EWL
BOD5
mg/L
289
219
260
261
625
525
652
548
453
380
558
468
614
498
567
659
734
848
446
175
182
304
885
170
120
138
Final Effluent (Annual Average)
BODs
mg/L
30
26
27
24
50
46
51
47
42
39
47
43
49
44
47
51
54
35
35
22
22
28
52
38
37*
38
TSS
mg/L
48
52
48
51
70
70
70
70
70
70
70
70
70
76
76
76
76
52
52
38
38
51
70
51
30*
48
BOD5
kg/kkg(lbs/ton)
6.9
4.5
4.0
3.1
9.3
10.15
9.45
10.4
7.8
8.6
8.7
9.5
11.15
12.1
12.95
14.05
14.85
3.95
3.1
2.2
2.0
4.0
5.3
2.4
3.5
4.0
(13.8)
< 9.0)
( 8.0)
( 6.2)
(18.6)
(20.3)
(18.9)
(20.8)
(15.6)
(17.2)
(17.4)
(19.0)
(22.3)
(24.2)
(25.9)
(28.1)
(29.7)
( 7.9)
( 6.2)
( 4.4)
( 4.0)
( 8.0)
(10.6)
( 4.8)
( 7.0)
( 8.0)
TSS
kg/klg(lbs/ton)
11.05
9.0
7.1
6.55
13.0
15.45
13.0
15.45
13.0
15.45
13.0
15.45
15.9
20.9
20.9
20.9
20.9
5.85
4.6
3.75
3.45
7.25
7.1
3.25
2.85
5.05
(22.1)
(18.0)
(14.2)
(13.1)
(26.0)
(30.9)
(26.0)
(30.9)
(26.0)
(30.9)
(26.0)
(30.9)
(31.8)
(41.8)
(41.8)
(41.8)
(41.8)
(11.7)
( 9.2)
( 7.5)
( 6.9)
(14.5)
(14.2)
( 6.5)
( 5.7)
(10.1)
* Basis for effluent limitations was kg/kkg(lbs/ton), not concentration; See text
-------
A total of 25 mills complied with both the daily maximum
BOD5_ and the maximum 30 day BOD5 limitations. Of these 25
mills, 12 mills complied with both the daily maximum TSS and
the maximum 30 day TSS limitations; however, TSS data were
not available for six of the 25 mills. Of the seven of the
25 mills for which TSS data were available, three mills
complied with one of the TSS limitations.
jBleached Kraft subcategories
Extensive effluent data were available for 32 bleached kraft
mills that have biological treatment facilities and the data
are summarized for the 32 mills in Table 87 in Section VII.
Of the 32 mills, 22 mills were determined to be best mills
as discussed in Section VII. The data for the best mills in
the bleached kraft subcategories are summarized in Table 150
which presents by subcategory the type of treatment system
in use at each mill, the raw waste BODjj concentration, and
final effluent flow, BOD5^ and TSS values. The BOD5_ and TSS
values are presented in both kg/kkg (Ibs/ton) and
concentrations. Details of the type of treatment system in
use by the best mills are shown in Figure 67 in Section VII.
In the bleached kraft subcategories, 12 mills were in
compliance with both the daily maximum BOD5 and the maximum
30 day BODfj effluent limitations. Of these 12 mills, five
mills complied with both the maximum 30 day TSS and the
daily maximum TSS limitations; however, data were
unavailable for three of the 12 mills. Two of the 12 mills
complied with the daily maximum TSS but exceeded the maximum
30 day TSS limitations, and two mills exceeded both the
daily maximum TSS and the maximum 30 day TSS limitations.
In addition, 7 other mills complied with at least one of the
limitations for BOD5 and TSS.
BleachedKraft Dissolving Pulp subcategory
Two of the three mills in the bleached kraft dissolving pulp
subcategory have biological treatment facilities and both
mills were determined to be best mills. As shown in Table
150, the average final effluent concentrations for BODS^ and
TSS for the two best mills are 30 mg/1 and 43 mg/1,
respectively. The effluent limitations were based upon the
following values;
Flow 230 kl/kkg (55.1 kgal/ton)
BOD5 30 mg/1
TSS U8 mg/1
571
-------
ISO
BLEACHED KRAFT SUBCATEQORIES
BEST MILLS: FINAL EFFLUENT CHARACTERISTICS
Mill
Dissolving Kraft
Final
Effluent
Flow
kl/kkg (kgal/ton)
127
108
Average
233
231
232
ui
Market Kraft
114 179
130 256
Average
218
(55.9)
(55.4)
(55.7)
(42.9)
(61.5)
(52.2)
131
295
213
276
120
198
Treatment
C-ASB
C-ASB
C-ASB
SB-ASB
BODS
kg/kkg (Ibs/ton)
5.4
8.5
4.6
2.9
3.8
(10.7)
(16.9)
6.9 (13.8)
( 9.2)
( 5.8)
( 7.5)
mg/L
23
37
30
26
11
18.5
TSS
kg/kkg (Ibs/ton)
8.6
11.1
9.9
3.8
6.5
5.2
(17.1)
(22.2)
(19.7)
( 7.5)
(13.0)
(10.3)
mg/L
37
48
43
21
25
23
BCT Papers
105
109
111
121
117
113
138
125
162
167
142
158
204
141
133
110
(38.9)
(40.0)
(34.1)
(37.9)
(49.0)
(33.7)
(32.0)
(26.4)
224
213
213
189
146
260
375
288
C-ASB-PS
C-ASB
C-ASB
C-ASB-PS
C-ASB
C-ASB
C-ASB
C-ASB
2.6
6.2
3.2
4.4
2.8
4.8
4.4
3.3
( 5.1)
(12.4)
( 6.3)
( 8.7)
( 5.5)
( 9.6)
( 8.8)
( 6.5)
16
37
22
28
13
34
33
30
17.0
6.5
5.7
4.8
9.1
6.1
(34.0)
(13.0)
(11.3)
( 9.6)
(18.1)
(12.2)
102
46
36
23
68
55
Average
148
(35.5)
239
4.0
( 7.9)
27
8.2
(16.4)
55
-------
TABLE 150
BLEACHED KRAFT SUBCATEGORIES
BEST MILLS; FINAL EFFLUENT CHARACTERISTICS
(cont.)
Mill
Final Raw
Effluent Waste
Flow BODS
kl/kkg (kgal/ton) wg/L
Final Effluent
BODS TSS
Treatmant kg/kkg (Itos/ton) mg/L kg/kkg(Ibs/ton)
u>
119
103
136
106
166
101
107
104
110
120
97.2
171
120
171
126
159
187
219
100
130
(23.3)
(40.9)
(28.7)
(40.9)
(30.2)
(38.2)
(44.8)
(52.5)
(24.0)
(31.2)
240
232
242
204
237
182
264
183
277
369
C-A
C-ASB-PS
C-A
C-ASB-PS
C-ASB
C-ASB-PS
C-A-PS
C-A
C-ASB-C
C-A
1.1
2.3
3.8
3.1
3.1
1.5
3.3
7.3
3.4
3.6
(2.25
(4.65
(7.6)
(6.25
(6.2)
(2.9)
(6.6)
(14.6)
(6.8)
(7.1)
11
31
32
18
27
9
18
33
34
27
Average
Average
(all mills)
243
235
24
25
3.3
1.6
29.9
3.5
5.4
2.1
12.1
13.6
7.0
13.8
6.9
7.5
( 6.5)
{ 3.2)
(59.8)*
( 6.95
(10.8)
( 4.2)
(24.1)
(27.2)
(13.9)
(27.6)
(13.8)
(14.9)
33
21
250
20
46
13
64
62
69
106
48
47
* Not included in averages.
-------
The above BOD5_ concentration is the average of the best
mills in the dissolving kraft subcategory. Since some mills
have been experiencing difficulties in achieving low levels
of TSS and the TSS value from mill 108 is relatively close
to the average for all of the best mills in the bleached
kraft subcategories, the TSS concentration from mill 108 was
used. The above flow, BOD5, and TSS values were used to
compute the annual average BOD5 and TSS values used as the
basis of the effluent limitations. The annual average
values were multiplied by the variability factors presented
in Table 148 in order to determine the maximum 30
consecutive days and maximum day effluent limitations.
Extensive TSS data were not available to determine
compliance for one of the mills, and of the two best mills
in the bleached kraft dissolving pulp subcategory both have
been determined to be in compliance with the daily maximum
BOD5_ and 30 day average BODjj and the one mill demonstrated
compliance with the maximum 30 day TSS limitation and only
exceeded the daily maximum limitation on one day out of 150
days of sampling data.
Bleached Kraft Market Pulp Suhcateqory
Four of the eight mills in the bleached kraft market pulp
subcategory have biological treatment facilities and data
were available for three of the four mills. As discussed in
Section VII, two of the three mills were determined to be
best mills. As shown in Table 150, the average final
effluent BOD5 and TSS concentrations for the two best mills
were 18.5 mg/1 and 23 mg/1, respectively. The average raw
waste BOD5 concentration for the two best mills was 198 mg/1
which is below the average subcategory BOD5 raw waste
concentration of 219 mg/1. The BOD5 effluent limitation was
therefore based upon mill 114's final effluent concentration
of 26 mg/1 which takes into account differences in the BOD5_
raw waste load.
The average final effluent TSS concentration for the best
mills was 23 mg/1 as shown in Table 150. However, the TSS
effluent limitation was based upon 52 mg/1 because of the
difficulty that some mills have been experiencing in
achieving low levels of TSS. The value of 52 mg/1 was
derived from the average final effluent TSS concentration
for the best mills in all four bleached subcategories which
use either ASB»s or A's without extensive post storage ponds
as shown in Table 91 in Section VII. The analysis in
Section VII of the effluent levels associated with the type
of treatment facility showed that final effluent TSS
concentrations were lower for mills using ASB's or A's
574
-------
followed by post storage ponds than for mills using only
ASB's or A's. Since some mills may not have the land
available necessary for installation of post storage ponds,
the final effluent TSS value was based upon the capabilities
of mills using only ASB's or A's.
The basis for the effluent limitations are therefore the
following:
Flow: 173 kl/kkg (41.6 kgal/ton)
BOD5_: 26 mg/1
TSS: 52 mg/1
The annual average BOD5_ and TSS values as determined from
the above were multiplied by the variability factors
presented in Table 148 to determine the maximum 30
consecutive day and maximum day effluent limitations.
Of the two best mills in the bleached kraft market pulp
subcategory, both were determined to be in compliance with
the maximum 30 day BOD5_, the daily maximum BOD5_, the maximum
30 day TSS, and the daily maximum TSS (except for one day
out of 194 sampling days for one of the mills) limitations.
Bleached Kraft BCT Papers Subcategory
As shown in Table 150, the average BOD5 and TSS
concentrations for the eight best mills in the bleached
kraft BCT papers subcategory were 27 mg/1 and 55 mg/1,
respectively. The average BOD5 raw waste concentration for
the best mills was 239 mg/1 which is slightly less than the
average for the subcategory of 260 mg/1. The raw waste BOD5_
concentrations of the best mills and the subcategory average
are relatively close and because the final effluent
concentration is more impacted by the treatment facility
than the raw waste BOD5_ as discussed in Section VII, no
adjustments in the final effluent BODj> value were determined
to be necessary. For example, mill 138 is achieving a final
effluent BODJ3 of 28 mg/1 with a raw waste BOD5_ of 375 mg/1.
Moreover, the average raw waste flow for the best mills is
118 kl/kkg (35.4 kgal/ton) which is nearly equal to the
subcategory raw waste flow of 148 kl/kkg (35.5 kgal/ton).
The average TSS concentration of the best mills was used as
the basis of the TSS effluent limitations except that the
TSS value from mill 109 was not included in the average
because the treatment system, as discussed in Section VII,
had design deficiencies relating to TSS reduction. The TSS
value from mill 121 was also not included because the mill
used a post storage pond following the ASB.
575
-------
The basis for the effluent limitations are therefore the
following:
Flow: 148 kl/kkg (35.a kgal/ton)
BOD5_: 27 mg/1
TSS: 48 mg/1
The annual average BOD5_ and TSS values as determined from
the above values were multiplied by the variability factors
in Table 148 in order to determine the maximum 30 day and
maximum day effluent limitations.
In the bleached kraft BCT papers subcategory, four of the
eight best mills complied with the daily maximum BOD5_ and
TSS maximum 30 day BOD5_ limitations. Of these four mills,
two complied with both the daily maximum TSS and the maximum
30 day limitations; however, one of the four mills did not
have TSS data available, and one mill of the four complied
with the maximum 30 day TSS but exceeded the daily maximum
TSS on only one day. In addition, one other mill complied
with the daily maximum BOD5, the daily maximum TSS, the
maximum 30 day TSS limitations, but exceeded the maximum 30
day BOD5_ limitation due to a two week period of unusually
high values.
Bleached Kraft Fine Papers Subcategory
As shown in Table 150, the average BODJ5 and TSS
concentrations for the ten of the eleven best mills
(excluding mill 112) in the bleached kraft fine papers
subcategory were 24 mg/1 and 48 mg/1, respectively. The
average BODji raw waste load for the ten best mills was 243
mg/1 which is nearly equal to the subcategory average of 261
mg/1. The TSS effluent limitations were based upon 51 mg/1
instead of the subcategory average of 48 mg/1 because only
the bleached kraft fine paper mills operating treatment
systems representative of BPCTCA and using treatment systems
without post storage ponds or ASB's followed by clarifiers
were included in the TSS averages (mills 107, 119, 166 and
104) .
The basis for the effluent limitations are therefore the
following:
Flow: 129 kl/kkg (30.9 kgal/ton)
BOD5: 24 mg/1
TSS: 51 mg/1
The annual average BOD5_ and TSS values as determined from
the above values were multiplied by the variability factors
576
-------
in Table 1U8 to determine the maximum 30 consecutive day and
maximum day effluent limitations.
In the bleached kraft fine papers sutcategory, six of the
eleven best mills complied with both the daily maximum BOD5_
and the maximum 30 day BOD5_ limitations. Of these six
mills, two complied with the daily maximum TSS and the
maximum 30 day limitations; however, TSS data were
unavailable for one of the six mills; two mills of the six
exceeded both the daily maximum TSS and the maximum 30 day
average TSS limitations. Also, one mill of the six complied
with the maximum 30 day TSS limitation, but exceeded the
daily maximum TSS limitation on one day out of 358 sampling
days; one additional mill complied with the maximum 30 day
TSS and daily maximum TSS limitations but due to aerator
failures exceeded the BOD5_ limitations.
Groundwood Subcategories
As discussed in Section VII, data were available for four
groundwood mills which have biological treatment systems.
Three of these mills were determined to be "best mills", and
the mills' effluent data are presented in Table 151.
The effluent limitations for the GW: CMN and the GW: Fine
Papers Subcategories were based upon an average of the final
effluent BOD5 and TSS concentrations of the three mills
included in Table 151. Mill 001, which is a chemi-
mechanical groundwood mill, is included in Table 151 because
of the similarity of BOD5_ load into biological treatment.
Mill 001's raw waste BOD5_ is 529, mg/1, as shown in Table 95
in Section VII, and is reduced by primary treatment to 205
mg/1. Thus, mill 001 was included in Table 151 because the
treatability of the waste waters are similar to groundwood
mill waste waters and the strength of the waste waters
receiving biological treatment are similar. The effluent
limitations were therefore based upon the demonstrated
achievable levels of BOD5_ and TSS and the subcategory raw
waste flows shown below:
Flow: 91.3 kl/kkg (21.9 kgal/ton) GW: Fine
Flow: 99.2 kl/kkg (23.8 kgal/ton) GW: CMN
BOD5: 22 mg/1
TSS: 38 mg/1
The effluent limitations for the thermo-mechanical and the
chemi-mechanical Subcategories were determined using the
average raw waste flow values (See Section V) and achievable
levels of BOD5_ and TSS determined through an examination of
the relationships between the influent BOD5 and the effluent
577
-------
TABLE 151
GROJNDWOOD SUBCATEGORIES
BEST MILLS
Mill
001
005
002
en
oo
Final
Effluent Flow
kl/kkg (kgal/ton)
91.8 (22.0)
97.6 (23.4)
98.4 (23.6)
Raw
Waste Final Effluent
BODS BOD5
mg/1 Treatment kg/kkg (Ibs/ton)
205* SB-ASB-C 2.1 (4.1)
183 SB-ASB 2.1 (4.1)
187 C-A 3.3 (4.6)
TSS
mg/1 kg/kkg (Ibs/ton)
22 3.2 (6.4)
21 2.5 (4.9)
23 5.4 (10.8)
Average
192
2.2
(4.3)
22
3.7
(7.4)
mg/1 Subcategpry
35 GW CMP
25 GW Fine
55 GW Fine
38
* Primary Treatment Effluent
-------
qualities. Both subcategories have raw waste BODj>
concentrations which are higher than the other two
groundwood subcategories. The estimated raw waste BOD5_
levels for the chemi-mechanical subcategory are 848 mg/1
(See Section V) which are substantially higher than any of
the other groundwood subcategories. Mill 001 has a raw
waste BOD5_ of 529 mg/1 and reduces the BOD5_ to 205 mg/1 by
primary treatment. Thus, some reduction of the raw waste
BOD5_ of 846 mg/1 can be expected but not necessarily as much
as mill 001 is demonstrating. Analysis of the chemi-
mechanical waste water treatability as demonstrated by mill
001 and comparison to other subcategories raw waste BOD5_
levels resulted in a BOD5_ level of 35 mg/1 on which the
effluent limitations were based. The thermo-mechanical
subcategory raw waste BOD5_ is 446 mg/1 which is higher than
the bleached kraft subcategory raw waste BOD5_ levels. Since
the biological treatability of groundwood waste waters is
similar to bleached kraft waste water as demonstrated by
groundwood mills 001, 002, and 005 which reduce their raw
waste BOD5_ levels of approximately 200 mg/1 to approximately
22 mg/1, the effluent limitations were based upon BOD5_
levels of 35 mg/1 and TSS levels of 52 mg/1. The level of
52 mg/1 was demonstrated to be achievable by mills using
only ASB's or A's without any post storage or clarifiers.
These levels are considered to be conservative since mill
001 has achieved levels of BOD5 and TSS of 22 mg/1 and 35
mg/1, respectively, with an influent BOD5 level to
biological treatment of 205 mg/1. The chemi-mechanical and
thermo-mechanical limitations were therefore based upon the
following:
Flow: 113 kg/kkg (27.0 kgal/ton):CMP
Flow: 88.0 kl/kkg (21.1 kgal/ton):TMP
BOD5: 35 mg/1
TSS: 52 mg/1
The annual average BODj> and TSS values as determined from
the above values for the four groundwood subcategories are
shown in Table 149 and were multiplied by the variability
factors presented in Table 148 in order to determine the
maximum 30 consecutive day and maximum day effluent
limitations.
In the groundwood subcategories two of the three best mills
complied with the daily maximum BOD5, the 30 day BOD5_, the
daily maximum TSS, and the 30 day TSS limitations; the third
mill had sampling and ammoniator problems which resulted in
excursions above the BOD5 and TSS limitations.
579
-------
The average of 30 consecutive days and maximum day zinc
effluent limitations for those mills using zinc hydrosulfite
in the manufacturing process were determined based upon an
effluent concentration of 1.5 mg/1 and 3.0 mg/lr
respectively, and the subcategory raw waste flows. The
above concentrations were based upon application of lime
coagulation and clarification technology to the zinc raw
waste load from mill 008 (shown in Section V) .
Sulfite Subcateqories
The effluent limitations for the sulfite subcategories were
determined through a slightly modified methodology than that
used for the other subcategories (i.e. bleached kraft)
because of (1) the higher raw waste loads associated with
the sulfite subcategories,(2) the limited application of
full scale biological treatment systems at sulfite mills,
and (3) the biological treatabilities of sulfite mill waste
waters. The effluent limitations were determined for each
sulfite subcategory by multipling the raw waste flow by the
achievable final effluent concentration which is similar to
the original methodology. The difference involves the
determination of the achievable BOD5 concentrations. The
raw waste flow used in the calculations was that determined
in Section V. The achievable effluent concentrations were
those determined through the analysis in Section VII which
examined the influent and effluent EOD5 concentrations for
sulfite mills using full scale biological treatment systems
as well as for mills using biological treatment pilot
plants. The design and operation of treatment facilities
treating sulfite mill waste waters were evaluated in order
to determine the relationships between influent and effluent
BOD5^ values for those mills for which extensive data were
available.
The sulfite manufacturing process results in much higher
BOD5_ raw waste loads than most of the other subcategories
ranging from less than 75 kg/kkg (150 Its/ton) to over 200
kg/kkg (400 Ibs/ton) with raw waste BOD5_ concentrations
ranging from less than UOO mg/1 to nearly 3,000 mg/1. The
subcategory average concentrations range from 400 mg/1 to
nearly 800 mg/1, and the raw waste concentrations in the
range of 2,000 to 3,000 mg/1 are actually associated with
the concentrated, low volume waste streams. Some sulfite
mills have segregated their waste streams and are treating
the high concentration, low volume waste streams in
biological treatment systems and treating the low
concentration, high volume waste streams by primary
treatment. The former waste streams are associated with the
pulping operations while the latter are from the papermaking
580
-------
operations. As discussed in Section VII, two mills, mills
053 and 401, are presently treating the highly concentrated
waste streams by biological treatment systems and the low
concentration streams by primary treatment.
Two mills, mills 051 and 052, are treating all of the waste
waters from both the pulping and papermaking operations.
However, the treatment facility at mill 052 has been
determined to be underdesigned and mill 51's treatment
facility has been determined to be operated at less than
maximum effectiveness. Mills 006 and 007 treat all of their
waste waters in biological treatment facilities but both
mills also employ groundwood pulping which has the effect of
diluting the raw waste load. Because of the limited
application of biological treatment systems representing
BPCTCA in the sulfite subcategories, data were used when
available from both full scale and pilot plant operations of
biological treatment facilities at sulfite mills.
The analyses of the influent and effluent data and the
biological treatment facilities were discussed in Section
VII. The results of a regression analysis are plotted in
Figure 70 in Section VII and the following relationship was
determined:
Log BODjj Eff = 0.496 Log BOD5 Inf + 0.309
Using the above relationship with the BOD5> raw waste
concentrations determined in Section V for each sulfite
subcategory and the allowances within each subcategory, the
following achievable BOD5_ effluent concentrations were
determined, which were used as the basis of the BOD5_
effluent limitations.
581
-------
Papergrade Sulfite (Blow Pit)
Bisulfite - Surface 50 mg/1
Bisulfite - Barometric 46 mg/1
Acid - Surface 51 mg/1
Acid - Barometric 47 mg/1
Papergrade Sulfite (Drum Wash)
Bisulfite - Surface 42 mg/1
Bisulfite - Barometric 39 mg/1
Acid - Surface 47 mg/1
Acid - Barometric 43 mg/1
Continuous Digesters 49 mg/1
Dissolving Pulp
Nitration Grade 44 mg/1
Viscose Grade 47 mg/1
Cellophane Grade 51 mg/1
Acetate Grade 54 mg/1
It should be pointed out that this methodology includes a
conservative factor in that the relationship above was
determined using influent to secondary treatment and the
achievable effluent concentrations were determined using raw
waste loads which are generally 10 - 15% higher than
biological treatment influent values.
Data from mill 051 has shown that BOD5_ levels less than 50
mg/1 can be achieved with full scale biological treatment
systems. The annual average BOD5_ concentration for mill 051
is 64.7 mg/1, but evaluation of the operation of the
treatment system has shown that BOD5 effluent concentrations
of less than 50 mg/1 can be consistently achieved when
operating at design efficiencies. During the winter months,
mill 051 shuts down two or three aerators.
The TSS effluent limitations were also determined using the
raw waste flow for each sulfite subcategory and achievable
TSS effluent concentrations. The achievable TSS
concentrations for each subcategory could not be determined
in a similar manner as the BODj> values because final
effluent TSS concentrations are impacted by both influent
TSS and influent BOD5 as well as the design and operation of
the treatment facilities. Extensive data were not available
in all cases in order to relate influent and effluent
values. Several of the mills using full scale systems
measure their TSS by non-standard methods (mills 006, 007,
052, 401). The only available TSS data from full scale
operations was from mill 051 and mill 053 which use an
aerated stabilization basin and an activated sludge system,
respectively. As shown in Table 81 in Section VII these
582
-------
mills were achieving average TSS concentrations of 60 mg/1
and 94 mg/1 with influent BODj> concentrations of 388 mg/1
and 2645 mg/1, respectively. Mill 051 as pointed out
previously was determined to operate the treatment facilites
at less than maximum effectiveness. Because of the limited
application of biological treatment systems, data were used
from both full scale and pilot plant operations in
determining TSS effluent concentrations that can be achieved
through proper application of BPCTCA. The papergrade
sulfite TSS effluent limitations were based upon 70 mg/1
which was the average of mills 051r 073, and 512 in Table
97. These three mills have raw waste concentrations most
representative of papergrade sulfite mills. The TSS
effluent limitations for the dissolving sulfite subcategory
was based upon 76 mg/1 as determined by averaging the TSS
data for mills 051, 073, 512, and 053 in Table 97.
Inclusion of mill 053 in the dissolving sulfite average was
due to the higher raw waste concentration at mill 053 which
is more representative of dissolving sulfite mills. It
should be pointed out that each TSS effluent limitation in
the papergrade subcategories including the allowances was
based on 70 mg/1 and each of the TSS allowances in the
dissolving sulfite subcategory were based upon 76 mg/1.
Using the raw waste flow value for each of the subcategories
as shown in Section V and the appropriate BOD5 and TSS
concentrations shown above, the annual average BOD5_ and TSS
values were determined. The maximum 30 consecutive days and
maximum day effluent limitations were determined by
multiplying the annual average values shown in Table 149 by
the variability factors in Table 148.
In the sulfite subcategories one mill presently complies
with the daily maximum BOD5_, the maximum 30 day BOD5_, and
the daily maximum TSS, and the 30 day TSS limitations.
Soda Subcategory
There are presently two mills in the soda subcategory, mills
151 and 152, and a third soda mill, mill 150, has recently
shut down operations. Mill 151 discharges its waste waters
to municipal treatment and mill 150 used a trickling filter
but as discussed in Section VII was ineffective in reducing
BOD5_ and TSS to acceptable levels. Mill 152 employs an ASB
to achieve final effluent BOD5_ and TSS qualities of 28 mg/1
and 107 mg/1, respectively. The treatment system in use by
mill 152 is deficient in the design for TSS reduction as
discussed in Section VII even though acceptable levels of
BOD5_ are being achieved.
583
-------
The effluent limitations were based upon BOD5 and TSS
concentrations of 28 mg/1 and 51 mg/1, respectively. The
BOD5_ value of 28 mg/1 was that being achieved by mill 152
and is similar to those levels being achieved by mills in
the bleached kraft subcategories. Following upgrading of
the treatment system for TSS reduction at mill 152, the
final effluent BOD5_ concentrations will probably be lower
due to more effective treatment and solids reduction. The
TSS value of 51 mg/1 was derived from the bleached kraft
fine papers subcategory. The soda manufacturing process is
very similar to the bleached kraft manufacturing process
(see Section III) and thereby the raw waste characteristics
and treatability are similar. Because of the similarities
in waste waters and treatabilities and since the treatment
facilities at mill 152 are not representative of BPCTCA, the
TSS effluent limitations were based upon 51 mg/1 which was
the basis for the bleached kraft fine papers subcategory TSS
effluent limitations.
The basis for the effluent limitations for the soda
subcategory are therefore the following:
Flow: 142 kl/kkg (34. 1 kgal/ton)
BOD5: 28 mg/1
TSS: 51 mg/1
The annual average BOD5_ and TSS values as determined from
the above values were multiplied by the variability factors
in Table 148 to determine the maximum 30 consecutive days
and maximum day effluent limitations.
In the soda subcategory, one mill complies with the daily
maximum BOD5_, the maximum 30 day average EOD5_, and the daily
maximum TSS, but has exceeded the maximum 30 day average
TSS.
Deink Subcateqory
Effluent data for the four deink mills for which data were
available with biological treatment facilities are shown in
Table 96 in Section VII. Schematics of the external
treatment facilities at these mills are presented in Figure
67. The treatment systems used by these mills involve
aerated stabilization basins, activated sludge, and a
modified activated sludge - aerated stabilization basin
system. Mill 300 is located in the Southwest and uses an
ASB followed by filtration to achieve total recycle of waste
waters. Table 213 presents influent and effluent waste
water characteristics for the deink mills which were used as
the basis of the effluent limitations and as shown, two of
584
-------
the four deink mills with biological treatment systems were
included. Since the deink process can create high raw waste
loads and have an effect upon final effluent qualities
depending upon the types of waste paper used, it was
determined to be necessary to increase the reliability of
the data base through inclusion of as many mills in Table
152 as appropriate.
The effluent limitations were therefore based upon the
following:
Flow: 102 kl/kkg (24.4 kgal/ton)*
BOD5_: 52 mg/1
TSS: 70 mg/1
*at 100% deink
The annual average BODjj and TSS values as determined from
the above are shown in Table 149 and were multiplied by the
variability factors in Table 148 in order to determine the
maximum 30 consecutive day and maximum day effluent
limitations.
In the deink subcategory, two mills complied with the daily
maximum BODJ5 and the maximum 30 day BOD5_ limitations. Of
these two mills, TSS data were unavailable for one of the
mills and the other mill exceeded the daily maximum TSS
limitation (4 times out of 359 data points) and the maximum
30 day limitation (one 30 day period was higher than the
limitation). One additional mill complied with the maximum
30 day BODJ5 and the maximum 30 day TSS limitations, but
exceeded the daily maximum TSS (once in 348 days of
sampling) and the daily maximum BOD5 limitations.
Non-Integrated Papers Mills Subcategories
Non-Integrated Fine Papers Subcategory
Effluent data for non-integrated fine paper mills are
summarized in Table 100 for those mills with primary and
secondary treatment systems. Schematics are presented for
non-integrated fine paper mills with biological treatment
facilities in Figure 67, Only two mills, 257 and 284, use
biological treatment systems for which data were available.
The final effluent BOD5_ concentrations for mills 257 and 284
were 86 mg/1 and 110 mg/1, respectively. In addition, the
TSS concentration for mill 284 was 102 mg/1. The average
BOD5 concentration for all the mills in Table 100 that have
primary treatment facilities was 86 mg/1 (excluding mill
279) indicating that primary treatment is not adequate to
585
-------
TABLE 3-52
DEINK SUBCATEGORy
BASIS FOR EFFLUENT UMtmTIONS
Ul
03
Mill Flow
kl/kkg (kgal/ton)
206
216
Average
87.2
76.3
81.7
(20.9)
(18.3)
(19.6)
Raw
Waste
BODs Treatment
683 C-ASB-C
687 C-A
685
BOD5
kg/kkg (Ibs/ton)
4.4 (8.8)
4.0 (7.9)
4.2 (8.4)
mg/1
51
52
52
TSS
kg/kkg (Ibs/ton)
8.0 (15.9)
3.7 ( 7.4)
5.9 (11.7)
mg/1
91
49
70
-------
achieve high quality effluents. The secondary treatment
systems in use by mills 257 and 281 were only achieving an
average BODj> concentration of 98 mg/1 which is also not a
high quality effluent indicating that the biological
treatment systems in use by the two mills are not
representative of BPCTCA.
Because no mills were demonstrating treatment systems
representative of BPCTCA, the effluent limitations were
based upon a BOD5 level of 38 mg/1 and a TSS level of 51
mg/1. Bleached kraft mills which used external treatment
systems representative of BPCTCA achieved final effluent
BOD5_ levels of 9 to 38 mg/1 with raw waste BOD5_ of 230 to
250 mg/1. Since less effective treatment would be expected
through treatment of lower raw waste BOD5_ levels (i.e., NI
fine papers: 170 mg/1), 38 mg/1 was used as the basis of the
BOD5_ effluent limitations. A level of 51 mg/1 was used for
the TSS limitations which is the same level as the bleached
kraft fine paper subcategory. The EODJ5 and TSS levels were
based upon the bleached kraft fine papers subcategory levels
since similar products are manufactured which result in
relatively similar waste waters in regards to the
papermaking operations. It should be pointed out that
several mills achieve or nearly achieve the effluent
limitations using only primary treatment. These mills use
extensive inplant controls as an alternative to external
controls representative of BPCTCA. The flow basis for the
effluent limitations was 63.3 kl/kkg (15.2 kgal/ton) as
determined in Section V.
The effluent limitations were therefore based upon the
following:
Flow: 63.3 kl/kkg (15.2 kgal/ton)
BOD5: 38 mg/1
TSS: 51 mg/1
The annual average BOD5_ and TSS values as determined from
the above and shown in Table 1U9 were multiplied by the
variability factors in Table 1U8 in order to determine the
maximum 30 consecutive day and maximum day effluent
limitations.
In the NI fine papers subcategory, two mills complied with
the daily maximum BOD5_, the maximum 30 day BOD5_, the daily
maximum TSS, and the maximum 30 day TSS limitations. One
mill had limited BOD£ data but did comply with the daily
maximum BODJ5 (data was insufficient for maximum 30 day BOD5_
and TSS comparisons as well as daily maximum TSS) . Two
mills complied with the maximum 30 day TSS and the daily
587
-------
maximum TSS but exceeded the BOD5 limitations. One mill
complied with the maximum 30 day TSS limitations but
exceeded the other limitations.
Non-Integrated Tissue Papers Subcategories
Table 101 shows effluent data for non-integrated tissue
mills and is divided into the following three groups: Group
1: 100% purchased pulp, Group 2: Purchased Pulp and Waste
Paper, Group 3: 100% Waste paper. BPCTCA for the non-
integrated tissue subcategory includes only primary
treatment as most of the BODji in the raw waste waters is
associated with the fibrous materials (TSS) in the mill
waste waters. In these cases, removal of the TSS also
removes a large amount of the raw waste BOD{>. Three forms
of primary treatment are used by NI tissue mills: (1)
clarifiers, (2) dissolved air flotation, and (3) settling
basins. Each of these is capable of achieving high quality
levels of BOD5_ and TSS in effluents from NI tissue mills.
Examination of the BOD5_ and TSS levels achieved by mills in
each of the three groups results in the following
conclusions:
(1) High quality effluents can fce achieved with primary
treatment by mills using 100% purchased pulp or by
mills using varying proportions of waste paper and
purchased pulp.
(2) Mills using 100% waste paper and primary treatment
cannot achieve similar quality effluents as mills
using purchased pulp with similar treatment
systems. This is due to higher levels of soluble
BODj> in the waste waters of mills using 100% waste
paper.
(3) Biological treatment is necessary for mills using
100% waste paper to achieve high quality effluents.
Since biological treatment is not the basis of the
limitations for NI tissue mills, the effluent limitations
were determined by averaging the final effluent BODji and TSS
values in kg/kkg (Ibs/ton) rather than using the RWL flow
and final concentrations. The NI tissue papers subcategory
effluent limitations are based upon the average of group 1
and 2 from Table 101.
The BOD5 and TSS values which were used as the basis of the
effluent limitations for the NI tissue papers subcategory
are therefore the following:
588
-------
BOD5: 3.5 kg/kkg (7.0 Ibs/ton)
TSS: 2.85 kg/kkg (5.7 Ibs/ton)
These values were determined from the data presented in
Table 153 along with their corresponding concentrations
using the subcategory raw waste flow of 95.5 kl/kkg (22.9
kgal/ton). In order to determine the maximum 30 consecutive
day and maximum day limitations, the annual average values
were multiplied by the variability factors in Table 148
which apply specifically to the NI tissue paper subcategory.
Because no mills were demonstrating treatment systems
representative of BPCTCA (biological treatment) for NI
tissue papers (fwp) mills, the effluent limitations were
based upon a BOD5_ level of 38 mg/1 and a TSS level of 48
mg/1. The bleached kraft segment achieved high quality
effluents ranging from 10 - 38 mg/1 and since non-integrated
tissue (FWP) mills are relatively small and have little
experience in achieving high quality levels of BOD5_ by
biological treatment, 38 mg/1 was used as the basis of the
BOD5_ effluent limitations. A level of 48 mg/1 was used for
the TSS limitation which was based upon the bleached kraft
BCT subcategory because of the similarities of the
papermaking operations.
The effluent limitations were therefore based upon the
following:
Flow: 105 kl/kkg (25.2 kgal/ton)
BOD5: 38 mg/1
TSS: 48 mg/1
The maximum 30 consecutive days and maximum day limitations
were determined by multiplying the annual average values
determined from the above values by the variability factors
shown in Table 148.
In the NI tissue subcategories, four mills complied with the
daily maximum BODj? and the maximum 30 day BOD5 limitations.
Of these 4 mills, two complied with both the daily maximum
TSS and the maximum 30 day TSS limitations; the other two
mills did not have TSS data available. In addition, three
mills having limited BOD5_ data complied with the daily
maximum BODjj limitation (data was insufficient for maximum
30 day BOD5_, and TSS comparisons except for one mill which
had limited TSS data and complied with the daily maximum TSS
limitation).
589
-------
Flow
Mill kl/kkg(kgal/ton)
en
to
o
308
325
318
315
306
252
319
208
329
302
310
324
309
333
259
326
115.5
130.9
140.5
66.3
43.4
48.0
120.1
61.3
153.9
50.9
96.7
94.7
69.6
133.4
73.8
72.6
(27.7)
(31.4)
(33.7)
(15.9)
(10.4)
(11.5)
(28.8)
(14.7)
(36.9)
(12.2)
(23.2)
(22.7)
(16.7)
(32.0)
(17.7)
(17.4)
Average 92.2 (22.1)
* Not included in averages
TABLE 153
NI TISSUE MILLS
BASIS FOR EFFLUENT LIMITATIONS
Raw Waste Load
BOD5
kg/kkgObs/ton)
16.7
8.7
7.3
22.8
11.7
7.4
13.6
14.6
9.6
(33.4)
(17.4)
(14.7)
(45.7)
(23.5)
(14.8)
(27.3)
(29.3)
(19.2)
TSS
kg/kkgdbs/ton)
30.1
25.7
35.8
72.0
36.6
22.4
51.5
25.2
32.1
( 60.3)
( 51.5)N
( 71.7)N
(145 )
( 73.3)N
( 44.8)
(103.0)
( 50.4)N
( 64.3)
12.5 (25.0)
41.7 ( 83.5)
Treatment
C
OAF
C
OAF
DAF
C-PS
SB
C
C
C-PS
C
SB
C
C
C, DAF
Final Effluent
BODS
kg/kkg(lbs/ton)
4.5 ( 9.1)
17.5 (35.1)*
3.5 ( 7.1)
4.4 ( 8.9)
1.0 ( 2.0)
3.4 ( 6.9)
2.5 ( 5.0)
6.2 (12.4)
6.1 (12.2)
3.3 ( 6.6)
2.7 ( 5.5)
1.4 ( 2.8)
1.9 ( 3.8)
4.8 ( 9.6)
3.9 ( 7.9)
2.4 ( 4.9)
3,5 ( 7.0)
TSS
kg/kkqObs/ton)
3.8
-
4.6
-
-
1.1
-
3.2
3.5
-
3.0
1.5
-
-
1.9
-
2.8
(7.7)
( - )
(9.3)
( - )
( „ )
(2,2)
( - )
(6.4)
(7.1
( - )
( - )
(3.0)
( - )
( - )
(3.9)
( - )
(5.7)
-------
PRETREATMENT REQUIREMENTS
No constituents of the effluent discharged from mills within
tne bleached kraft, groundwood, sulfite, soda, deink, and
non-integrated paper mills segment of the pulp, paper, and
paperboard point source category have been identified which
would interfere with, pass through, or otherwise be
incompatible with a well-designed and operated publicly
owned biological waste water treatment plant. The exception
to this, however, is the discharge of zinc from groundwood
mills which use zinc hydrosulfite as a bleaching agent.
Pretreatment standards on zinc which are equal to the BPCTCA
limitations were proposed for groundwood mills using zinc
hydrosulfite. The pretreatment standards can be achieved by
substituting sodium hyrosulfite for zinc hydrosulfite in the
bleaching process which is commonly practiced by many
groundwood mills.
591
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SECTION X
ACKNOWLEDGEMENTS
The Environmental Protection Agency wishes to acknowledge
the contributions of WAPORA, Inc., E. C. Jordan Co., and
General Data Systems, Inc. The efforts of E. N. Ross,
William Groff, and Dr. Harry Gehm of WAPORA; James
Vamvakias, Donald R. Cote, Martin Grant, Willard Warren and
Craig Aderman of E. C. Jordan; and John Rhinney of General
Systems Corporation (Maryland) are appreciated. Special
recognition is given to Donald R. Cote, E. C. Jordan Co.,
for his extensive efforts in providing the Agency with
technical assistance which was essentail to the successful
completion of the project.
Appreciation is expressed for the contributions of several
individuals within the Environmental Protection Agency:
John Riley, Effluent Guidelines Division, Bruce Diamond,
Office of General Counsel, Irving Susel and Ed Brandt,
Office of Planning and Evaluation, and Ernst Hall, Harold
Cougnlin, and Jeff Denit, Effluent Guidelines Division. The
support and direction by Allen Cywin, Office of Water and
Hazardous Materials, and Robert Schaffer, Effluent
Guidelines Division, were certainly appreciated.
Efforts by several members of the EPA working group/steering
committee deserve special acknowledgement and the technical
assistance and support provided to the project officer are
appreciated. Those members include: Danforth Bodien,
Region X, Joe Davis, Region III, Tom Doane, Region I, Frank
Early, NEIC-Denver, John Moebes, Region IV, John Schluter,
Region II, and Ralph Scott and Kirk Willard, National
Environmental Research Center at Corvallis, Oregon.
The assistance of Fred Zaiss, Office of Analysis and
Evaluation, in providing timely computer support is very
much appreciated.
The efforts of Arthur Shattuck, Effluent Guidelines
Division, are recognized and appreciated. Mr. Shattuck
prepared much of the recently acquired mill data for
computer input and conducted investigations into such
special tasks as woodyard and paper mill operations.
Appreciation is also extended to Charles G. Nichols,
Effluent Guidelines Division, for his assistance in revising
portions of the original draft report and in compiling the
many tables and figures. The efforts of Karla Jean Dolum
for her - continuous assistance throughout the project were
593
-------
invaluable. Of course, the accompaniment and enlightenment
provided by Creighton Karl and Cameron Kreig during evening
work sessions were essential to successful completion of the
project. Special recognition is given to Pearl Smith who
typed much of this document and has put up with the constant
harassment of the project officer. Assisting Pearl Smith
were Jane Mitchell, Doris Clark, Kaye Starr and Nancy
Zrubek.
The cooperation of the National Council for Air and Stream
Improvement in providing liaison with the industry and
technical assistance were appreciated. Thanks are also
extended to the American Paper Institute for its assistance.
Appreciation is also extended to companies who granted
access to their trtills 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.
594
-------
SECTION XI
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595
-------
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596
-------
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597
-------
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598
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52. Blosser, R. O., and Gellman, I.,"Characterization
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599
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63. Edde, H., "Settleable Solids Removal Practices in
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600
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601
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602
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-»
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11
-------
116. "Rapping with Rapson," Pulp & Paper, Oct. (1973) .
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6 (1973).
125. Warren, C.E., Biology of Water Pollution Control,
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127. Nowacki, J., "Nutrient Salt Reduction in the
Biological Purification of Kraft Mill Effluents,"
Fortachr Wassechen ihrev Grengzch til, 135 (1969).
128. Nowacki, J.r "Influence of Addition of Phosphorus
and Nitrogen to Pulp and Paper Mill Effluents,"
Pregeglad Papier 25, (6), 211, Poland, June
(1969) .
129. Tracy, J. C., "Secondary Waste Treatment Nutrient
and Aerator Studies", Southern Pulp and Paper
Manufacturer, Feb. 1970.
604
-------
130. Eckenfelder, W. W., Jr., Industrial Waste Water-
Control, Hill Book Co., New York (1966).
131. Edde, H., "Field Research Studies of Hydraulic
Mixing Patterns in Mechanically Aerated
Stabilization Basins," Proceedings International
Congress on Industrial Waste Waters, Stockholm
(1970) .
132. McKeown, J. J., and Buckley, D. B., "Mixing
Characteristics of Aerated Stabilization Basins,"
TAPPI 8th Water and Air Conf. (1971).
133. Grader, R. J., et al., "The Activated Sludge
Process Using High-Priority Oxygen for Treating
Kraft Mill Wastewater," TAPPI, 56, 4 (1973).
134. Ayers, K. C,, and Patton, T. H., Jr., "Biological
Treatment Alternatives for Kraft Effluents," TAPPI
8th Water and Air Conf. (1971).
135. Bennett, D. J., et al., "Pilot Application of the
Rotating Biological Surface Concept for Secondary
Treatment of Insulating Board Mill Effluents,"
TAPPI, 56, 12 (1973) .
136. Edde, H., "A Manual of Practice for Biological
Waste Treatment in the Pulp and Paper Industry,"
NCASI Technical Bulletin No. 190 (1966).
137. "Temperature Relationships in Aerobic Treatment and
Disposal of Pulp and Paper Wastes," NCASI Technical
Bulletin No. 191 (1966).
138. Pelzar, M.J., Jr., Reid, R.D., "Microbiology",
McGraw-Hill Book Company, 1972.
139. Benedict, A.M., and Carlson, D.A., "Temperature
Acclimation in Aerobic BlO-oxidation Systems,11
Journal Water Pollution Control Fed, 45, 10 (1973).
1UO. Serafin, J. F., and Axen, A., "Oxygen Bleaching at
Aspa Bruk Division of Munksjo A B, Sweden," TAPPI
Annual Meeting, Jan. 1416 (1974).
141. Oledal, J., "Use of the Multi-Roll Press for
Dewatering Clarifier Sludges," Paper Trade Journal,
Jan. 7 (1974) .
605
-------
142. Carpenter, W. L., "Mechanical Pressing of Primary
Dewatered Paper Mill Sludges," NCASI Technical
Bulletin No. 174 (1964).
143. "Great Lakes Has Copeland System to Handle Bark
Fines and Sludge," Paper Trade Journal, Oct. 2
(1972).
144. Aspitarte, T. R., et al., "Pulp and Paper Mill
Sludge Utilization and Disposal," TAPPI
Environmental Conf. (1973) .
145. Harkin, J. M., and Crawford, D. L., "Bacterial
Protein from Paper Mill Sludges," TAPPI
Environmental Conf. (1973) .
146. Vercher, B. D., et al., "Paper Mill Waste Water for
Crop Irrigation and Its Effects on the Soil,"
Louisiana State Univ. Agricultural Experiment
Station Bulletin No. 604 (1965).
147. Gehm, H. W., "Control of Sulfite Pulping Wastes in
the United States," Pure and Applied Chemistry, 29,
281 (1972) .
148. Gehm, H. W., "Factors Affecting the Appearance of
surface Waters," NCASI Technical Bulletin No. 227
(1969) .
149. Palladino. A. J., "Final Report -- Aeration
Development Studies,"
NCASI Technical Bulletin No. 12 (1959).
150. Blosser, R. 0., "Oxidation Pond Studies for
Treatment of Deinking Wastes,11 Purdue Univ.
Industrial Waste Conf. XVII (1962) .
151. Laing, W. M., "New secondary Aerated Stabilization
Basin at the Morraine Division of Kimberly-Clark
Corp.," Purdue Univ. Industrial Waste Conf. XXIV
(1969) .
152. MacAleese, J. E., "How Newton Falls Solved a Clean
Water Problem," Paper Trade Journal, Nov. 14
(1966) .
153. Flower, W. A., "Spray Irrigation for the Disposal
of Effluent Containing Deinking Waste," TAPPI, 52,
1267 (1969) .
606
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154. "Wisconsin Tissue Effluent Plant Pioneers European
Process Here," Paper Trgde Journal, March 11
(1970) .
155. Nadelman, A. H., "A Study of Practical Approaches
to Utilization of Solids from Deinking Mills,"
NCASI Technical Bulletin No. 67 (1964).
156. Davis, W. s., et al., "Recycling Fine Paper Mill
Effluent by Means of Pressure Filtration," TAPPI
Environmental Conf. (1972) .
157. Aldrich, L. C., and Janes, R. L., "White Water
Reuse on Fine Paper Machines," TAPPI Environmental
Conf. (1972) .
158. "New Approaches to In-Plant Load Control and
Monitoring," NCASI Technical Bulletin No. 248
(1971).
159. Mason, O.A., Statement by Alaska Lumber and Pulp
Co., Inc., for EPA Public Meeting Concerning
National Pollutant Discharge Elimination System
(NPDES) , Application No. Q71-OYD-2-000055 and
Proposed Permit.
160. "G-P's *Pipe Organ* Aeration System,"
Southern Pulpand Paper Manufacturer, May 10
71972) .
161. "K-C to Spend $92 Million at Coosa Pines Mill to
Boost Pulp Output and Control Pollution,"
Paper Trade Journal, May 20 (197/4) .
162. Tall oil and Its Uses, Pulp Chemicals Assn., New
York (1965) .
163. Ellerbe, R. W., "Why, Where and How U.S. Mills
Recover Tall Oil Soap," Pager Trade Journal, June
25 (1973).
164. "Resource Engineering Associates, "State-of-the-Art
Review on Product Recovery," FWPCA Contract No. 14-
12-495, Nov. (1969).
165. Stengle, W. B., "Crude Tall oil Manufacture,"
Southern Pulpand Paper Manufacturer, Dec. 10
(1971) .
607
-------
166. Drew, J., and Pylant, G. D., Jr., "Turpentine from
the Pulpwoods of the United States and Canada,"
TAPPI, 49, 10 (1966) .
167. Ores, J.,et al., Sulfate Turpentine Recovery, Pulp
Chemicals Assn., New York (1971).
168. "Tapping the Chemical Motherlode of the Southern
Pines," Chem 26/ Paper Processing, 9, 11 (1973).
169. Hearon, W. H., "The Lignin Dimethyl Sulfide
Process," Forest Products Journal, 7, 13 (1957).
170. Barton, J. S., "Future Technical Needs and Trends
of the Paper Industry, By-Products Usages,"
TAPPI, 56, 6 (1973).
171. Elgee, H., "A View of the Ligno-Sulfonate
Industry," AIChE Symposium Series, 133, 69 (1973).
172. Craig, D., "Justification for Pulp and Paper By-
products Development," AIChE Symposium Series, 133,
69 (1973) .
173. Pearl, I. A., "Utilization of By-Products of the
Pulp and Paper Industry," TAPPI, 52, 7 (1969).
174. Wiley, A. J., and Holderby, J. M., "Strong Spent
Sulfite Liquors: Utilization, By-Products and
Marketing," Pulp and Paper Magazine of Canada, 61,
3 (1960) .
175. "Chemicals from the Other Half of the Tree,"
Chemical and Engineering News, 41, 6 (1963).
176. Howard, G. C., U.S. Patent No. 1,699,845 (1929).
177. Serafin, J. F., and Axen, A., "Operating Experience
of the Chemetics1 Oxygen Bleaching Systems," TAPPI
Annual Meeting, Jan. 14-16 (1974).
178. Robeson, J. S., U.S. Patents No. 1,075,856;
1,075,857; 1,069,029; and 1,069,030 (1913).
179. Lang, C. J., and DeHaas, G. G., "Acetic Acid
Recovery from Sulfite Liquor," TAPPI, 53, 6 (1970).
180. Testimony of Roland J. Stanton, Technical Director,
Ketchikan Pulp Co., Ketchikan, Alaska, EPA Hearing,
608
-------
EPDES Permit Application No. 081-OY2-2-000094, Aug.
16 (1973) .
181. Gehm, H. W., "An Overview of Water Reuse Potential
in Pulp and Paper Manufacture," Paper presented to
AIChE, Washington, D.C., April 26 (1973).
182. Hendrickson, E. R., and Oglesby, H. S., "Process
Design and Operation for Zero Effluent Discharge,"
TAPPI, 57, 4 (197U) .
183. Haynes, D. C., "Water Recycling in the Pulp and
Paper Industry," TAPPI, 57, 4 (1974) .
184. "Cost of Achieving EPAfs BPCTCA and Zero
Discharge," Paper Trade Journal, April 15 (1974).
185. Gullichsen, J., "Status of Kamyr Displacement
Bleaching Project," Paper Trade Journal, July 30
(1973) .
186. "New Pulp Bleaching System to be Part of Eastex
Mill Expansion," Paper Trade Journal, Apr. 29
(1974) .
187. Serafin, J. F., and Andrews, D. H., "Oxygen
Bleaching Development from Laboratory Scale
Experiments to Full Scale Commercial Installation
and Operation," TAPPI Annual Meeting, Jan. 14-16
(1974) .
188. Lowe, K. E., "Chesapeake Launches Oxygen
Bleaching," Pulp and Paper, Oct. (1973).
189. Private Communication (1974).
190. Fary, D. A., and Schmitt, "Oxygen Bleaching at
Chesapeake Corporation," TAPPI Environmental Conf.,
Apr. 17-19 (1974) .
191. Standard Methods for the Examination of Water and
Wastewater, APHA, AWWA, and WPCF, American Public
Health Assn., Inc., New York (1971).
192. "An Investigation of Improved Procedures for
Measurement of Mill Effluent and Receiving Water
Color," NCASI Technical Bulletin No. 253 (1971).
193. Kreissl, J. F., "Granular Media Filtration of
Wastewater: An Assessment," EPA, National
609
-------
Environmental Research Center, Advanced Waste
Treatment Research Laboratory, Cincinnati, Ohio,
Jan. (1973).
19U. Cruver, J. E., "Reverse Osmosis for Water Reuse,"
Gulf Environmental System Co., Paper presented at
the National Conf. on Complete Water Reuse,
Washington, D.C., Apr. (1973).
195. Schwonke, P. A., and Davis, W. S.f "Enzyme Enhanced
Turbidity Removal through Primary Treatment,"
TAPPI, 56. 1 (1973).
196, Baumann, E. R.,"Design of Filters for Advanced
Wastewater Treatment," Iowa State University,
Department of Civil Engineering, Paper presented at
EPA Technology Transfer Design Seminar, Ames, Iowa,
June (1973) .
197. Weber, Walter J., Jr., Physico-chemical Processes
for Water Quality Control, Wiley-Interscience, New
York 1972.
198. Pilot Plant Studies of Turbidity and Residual Cell
Materia.1 Removal from Mill Effluent by_ Granular
Media Filtration. NCASI Tech. Bull. No. 266, May
1973.
199. Tchobanoglous, G., "Filtration Techniques in
Tertiary Treatment, Journal Water Pollution Control
Federation, 42, April 1970.
200. Tchobanoglous, G., and Eliassen, R., "Filtration of
Treated Sewage Effluent," Journal of the Sanitary
Engineering Division, ASCE, April 1970.
201. Gulp, G.L., and Hansen, S.P., "Extended Aeration
Polishing by Mixed Media Filtration", Water and
Sewage Works, February 1967.
202. Gulp, R. L., and Gulp, C.L., Advanced Wastewater
Treatment, Van Nostrand Reinhold, New York, 1971.
203. Vecchiolo, Jr., et. al., "Wastewater Reclamation
and Recharge, Bay Park, New York, Journal Sanitary
Engineering Division ASCE, April 1975.
204. Middlebrooks, E.J., et. al., "Evaluation of
Techniques for Algae Removal from Wastewater
Stabilization Ponds," Utah Water Research
610
-------
it>,! v v-taij :.-.t.;-A.e University, Logan, Utah,
January 1 ')'/«"'
205. Baunioum. v: '. , '"Deb-,,n of Filters for Advanced
Waste Water Treatment.," Project 1002-S, Engineering
Research .r-ost.i-Lut-ri., Iowa State University, Ames,
Iowa, June 19/3,,
206. Leitner, G, F. , "Reverse Osmosis For Waste Water
Treatment - What? When?," TAPPI 8th Water & Air
Conf . (1971) .
207. Morris, D. C.. , Nelson, W. R. , and Walraven, G. O. ,
Recycle of Paper Mill Wastewaters and Application
2f. Reverse Osmosis, Green Bay Packaging, Inc. , EPA
120UO FEB, Jan. (1972) .
208. Wiley, A. J.f Dubey, G. A., and Bansal, J. K. ,
Reverse Osmosis Concentration of Dilute Pulp and
Paper Effluents^ The Pulp Manufacturers Research
League and The Institute of Paper Chemistry, EPA
120UO EEL Feb.
209. Johnson, J. S., Jr., Minturn, R. E., and Moore, G.
E. , Hyper filtration (Reverse Osmosis) of Kraft Pulp
Miri and Bleach Wastes, Chemistry Division, Oak
Ridge National Laboratory (unpublished) (1973) .
210. Beder, H. , and Gillespie, W. J. , "The Removal of
Solutes from Pulp Mill Effluents by Reverse
Osmosis," TAPPI^JjjJ, 5 (1970).
211. Smith, R.f and McMichael, W. F. , Cost and
Performance Estimates for Tertiary Wastewater
Treatment Processes, FWPCA, U.S. Dept. of the
Interior, June (1969) .
212. Direct Filtration of Secondary Effluents, EPA
Technology Transfer Program, Engineering Research
Institute; Iowa State University, Ames, Iowa;
Newark, N-J,, Mar, 13-15 (197U) .
213. Ultra High Rate Filtration .of Activated Sludge
Plant Effluent, EPA office of Research and
Monitoring, Washington, D.C., Apr. (1973).
21 U. Nelson, W. R. , Walraven, G. O. , and Morris, D. C. ,
"Process Water Reuse and Upset Control Modification
at an Integrated NSSC Mill," TAPPI, 56, 7 (1973).
611
-------
215. McCuaig, W. B., Atkins, P. F.» Jr., and Lueck, B.
L., Physical/Chemical Treatment of Combined
Municipal Pulp and Paper pastes, TAPPI
Environmental Conf. (1971).
216. Bishop, H. K., Use of Improved Membranes in
Tertiary Treatment by Reverse Osmosis, McDonnell
Douglas Astronautics Company, EPA 17020 DHR, Dec.
(1970) .
217. Kreusch, E., and Schmidt, K., Wastewater
Deminerali za. tion by Ion Exchange, Culligan
International Co., EPA 17040 EEE, Dec. (1971).
218. Herbert, A. J., "A Process for Removal of Color
from Bleached Kraft Effluents through Modification
of the Chemical Recovery System," NCASI Technical
Bulletin No. 157 (1962), U.S. Patent i 3,120,164.
219. Berger, H. F., and Thibodeaux, L. J., "Laboratory
and Pilot Studies on Water Reclamation," NCASI
Technical Bulletin No. 203 (1967).
220. Linstedt, K. D., Houck, C. P., and O'Connor, J. T.»
"Trace Element Removals in Advanced Wastewater
Treatment Processes," Journal WPCF, 43, 7 (1971).
221. Gregory, J., and Dhond, R. V., "Wastewater
Treatment by Ion Exchange," WaterResearch (Great
Britain), Pergamon Press (1973).
222. Gulp, R. L. , and Gulp, G. L.,
Advanced Waste Treatment, Van Nostrand Reinhold,
New York (1971).
223. Optimiz ation of Ammonia Removal by Ion Exchange
Using Clinoptilolite, University of California, EPA
17080 DAP, Sept. (1971).
22U. Wastewater Ammonia Removal by Ion Exchange,
Battelle-Borthwest, EPA 17010 EEZ, Feb. (1971).
225. Johnson, W. K., and Vania, G. B., Nit r i ficati on and
Denitrification of Waste Water, University of
Minnesota, EPA Research Grant Number WP 01028, Jan.
(1971).
226. Nitrogen Removal From Wastewaters, EPA Federal
Water Quality Research Laboratory, Advanced Waste
612
-------
Treatment Research Laboratory* Cincinnati, Ohio,
Oct. (1970).
227. Shindala, A., "Nitrogen and Phosphorus Removal From
Wastewaters - Part I," Water and Sewage Works, June
(1971).
228. Shindala, A., "Nitrogen and Phosphorus Removal From
Wastewaters - Part II," Water and Sewage Works,
July (1971) .
229. Process Design Manual for Carbon Adsorption, EPA
Technology Transfer, Oct. (1973).
230. Hansen, S. P., and Burgess, F. J., "Carbon
Treatment of Kraft Condensate Wastes," TAPPI, 51, 6
(1968) .
231. Rimer, A. E., et al., "Activated Carbon System for
Treatment of Combined Municipal and Paper Mill
Waste Waters in Fitchburg, Mass.," TAPPI, 54, 9
(1971).
232. Smith, D. R., and Berger, H. F., "Waste Water
Renovation," TAPPI, 51, 10 (1968).
233. Timpe, W. G., The Use of Activated Carbon for Water
Renovation in Kraft Pulp and Paper Mills.. 7th
TAPPI Air and Water Conf., (1970).
234. Timpe, W. G., and Lang, E. W., "Activated Carbon
Treatment of Unbleached Kraft Effluent for Reuse -
Pilot Plant Results," TAPPI Environmental Conf.
(1973).
235. Coates, J. and McGlasson, W. G., "Treatment of Pulp
Mill Effluents With Activated Carbon," NCASI
Technical Bulletin No. 199 (1967).
236. Davies, D. S. and Kaplan, R. A., "Activated Carbon
Eliminates Organics," Chemical Engineering
Progress, 60, 12 (1964).
237. Bishop, D. F., et al.,"Studies on Activated Carbon
Treatment," Journal WPCF, 39, 2 (1967).
238. Vanier, C., et al., Carbon Column Operation in
Waste Water Treatment, Syracuse University,
Syracuse, New York, Nov. (1970) .
613
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239. Weber, W. J., Jr., and Morris, J. C., "Kinetics of
Adsorption in Columns of Fluidized Media," Journal
WPCF, 37, 4, (1965) .
240. Beebe, R. L., and Stevens, J. I., "Activated Carbon
System for Wastewater Renovation," Water and Wastes
Engineering, Jan. (1967).
241. Holm, J. D., "A Study of Treated Wastewater
Chlorination," Water and Sewage Works, Apr. (1973).
242. Meiners, A. F. , Light-Catalyzed Chlorine Oxidation
for Treatment of Wastewater, EPA, Water Quality
Office, Midwest Research Institute, Kansas City,
Missouri, Sept. (1970).
243. Huibers, T. A., et al., Ozone Treatment of
Secondary Effluents from Wastewater Treatment
Plants, EPA, Robert A. Taft Water Research center,
Report No. TWRC-4, Apr. (1969).
244. Chen, J. W., and Smith, G. V., Feasibility Studies
of. Appl icat ions of Catalytic Oxidation in
Wastewater, EPA, Southern Illinois University,
Carbondale, Illinois, Nov. (1971).
245. Eckenfelder, W. W., Jr., Krenkel, P. A., and Adams,
C. A., Advanced Waste Water Treatment, American
Institute of Chemical Engineers, New York (1972) .
246. Moggio, W. A., "Experimental Chemical Treatments
for Kraft Mill Wastes," NCASE Technical Bulletin
No., 50 (1952) .
247. Oswalt, J. L., and Lund, J. G. , Jr., Color Removal
from Kraft Pulp Mill Effluents by Massive Lime
Treatment, EPA 12040 DYD (1973).
248. Swanson, J. W., et al., Kraft Effluent Color
Characterization Before and After Stoichiometric
Lime Treatment, EPA 12040 DKD (1973).
249. Lowe, K. E., "Is Pulping Technology on Verge of
Revolution," Pulp and Paper, July (1974).
250. Private Communication, Interstate Paper Corporation
(1973).
614
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251. Rapson, W. H., and Reeve, D. W. , "Bleached Kraft
Pulp Mills Can be Made Free of Liquid Effluents,"
Paper Trade Journal, Oct. 16 (1972).
252. Ranhagen, G., "The Entirely Closed Mill - A Utopia
or a Realistic Approach," Paper Trade Journal, Jan.
22 (1973) .
253. Chang, H., Reeves, R. H., McKean, W. T. , and
Gratel, J. S., "Seminar on Soda-Oxygen Pulping Held
by North Carolina State University,"
Paper Trade Journal, Sept. 10 (1973).
254. Gilmont, P. L., "Water Requirements of Pulp
Bleaching - Survey of Mill Practice in the United
States," TAPPI, 50, 10 (1967).
255. Histed, J. A., and Nicolle, F. M. A., "Water Reuse
and Recycle in Kraft Bleacheries," Pulp and Paper
Magazine of Canada, 74, 12 (1973).
256. Histed, J. A., and Nicolle, F. M. A., "Water Reuse
and Recycle in the DcEDED Bleach Sequence," CPPA-
TAPPI Conf., Vancouver, B.C. Sept. (1973).
257. Gall, R. J., and Thompson, F. H., "The Anti-
Pollution Sequence - A New Route to Reduce
Pollutants in Bleach Effluent," TAPPI, 56, 11
(1973).
258. Improved Machinery, Inc., Impco Papribleach Pulp
Bleaching Process, (Trade Pamphlet), Nashua, N.H.
(1972).
259. Jamieson, A., Noreus, S., and Pettersson, B.,
"Advances in Oxygen Bleaching III, Oxygen Bleaching
Pilot Plant Operation," TAPPI, .54, 11 (1971).
260. Lescot, J. C., "Oxygen Bleaching - A Flexible
Process for Pollution Abatement," CPPA-TAPPI Conf.,
Vancouver, B.C., Sept. (1973).
261. Lowe, K. E., "Bleaching at Crossroads," Pulp &
Paper, Aug. (1973) .
262. Carpenter, W. L., McKean, W. T., Berger, H. F., and
Gellman, I., "A Comparison of Effluent
Characteristics from Conventional and Oxygen
Bleaching Sequences - Results of a Laboratory
615
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Study," CPPA-TAPPI Conf., Vancouver, B.C., Sept.
(1973).
263. Berger, H. F. , "Development of an Effective
Technology for Pulp and Bleaching Effluent Color
Reduction," NCASI Technical Bulletin No. 228,
(1969) .
26U. Spruill, E. L., Draft of Final Report, Color
Removal and Sludge Disposal Process for Kraft Mill
Effluents, EPA 12040 DRY (1973).
265. "Treatment of Calcium-Organic Sludges Obtained From
Lime Treatment of Kraft Pulp Mill Effluents -- Part
I," NCASI Technical Bulletin No. i&_2 (1955) .
266. "Treatment of Calcium-Organic Sludges Obtained From
Lime Treatment of Kraft Pulp Mill Effluents — Part
II," NCASI Technical Bulletin No. 75 (1955).
267. "Development Studies on the Removal of Color from
Caustic Extract Bleaching Effluent by the Surface
Reaction Process -- Part II," NCASI Technical
Bulletin No. 107 (1958) .
268. Berger, H. F., and Brown, R. I., "The Surface
Reaction Method for Color Removal from Kraft
Bleachery Effluents," NCASI Technical NCASI
Technical Bulletin No. 122 (1959).
269. "Development Studies on the Removal of Color from
Caustic Extract Bleaching Effluent by the Surface
Reaction Process — Part II," NCASI Technical
Bulletin No. 122 (1959) .
270. Davis, C. L., Color Removal from Kraft Pulping
Effluent b_Y Lime Addition, Interstate Paper
Corporation, EPA 120UO ENC (1971).
271. Spruill, E.L., Color Removal and Sludge Recovery
from Total Mill Effluent, TAPPI Environmental Conf.
(1972) .
272. Gould, M., Color Removal from Waste Effluents, U.S.
Patent 3,531,370 (1970).
273. Spruill, E. L., "Color Removal from Paper Mill
Waste," Proceedings Purdue Univ. Industrial Waste
Conf. XXV (1970) .
616
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274. Private Communication, Continental Can Company,
Inc. (1973).
275. Gould, M., "Color Removal from Kraft Mill Effluent
by an Improved Lime Process," TAPPI, 56, 3 (1973).
276. Sould, M., "Physical - Chemical Treatment of Pulp
Mill Wastes, Woodland, Me.," Proceedings Purdue
Univ. Industrial Waste Conf. XXV (1970).
277. Private Communication, Georgia Pacific Corporation
(1974) .
278. Private Communication, International Paper Company
(1974) .
279. Berov, M. B., et al., "pH and the Effectiveness of
Effluent Treatment," Burn* Prom. (USSR), No. 2,
6(1973); Abs. Bull. Inst. Paper Chem., 44, 1561
(1973) .
280. Willard, H. K., "Coagulation of Pulp and Paper
Aerated Lagoon Effluents for Color and Solids
Removal," AIChE Symposium Series, 69 (1973).
281. Smith, S. E., and Christman, R. F., "Coagulation of
Pulping Wastes for the Removal of Color,"
Journal WPCF, 41, 2., Part I, (1969).
282. Middlebrooks, E. J., et al., "Chemical Coagulation
of Kraft Mill Wastewater," Water and Sewage Works,
116, 3, (1967).
283. Scott, R. H., "Sophisticated Treatment at Baikal
Pulp Mill in U.S.S.R.," Pulp and Paper, Apr.
(1974) .
284. Private Communication, Gulf States Paper,
Tuscaloosa, Alabama (1974) .
285. Fremont, H. A., Tate, D. C., and Goldsmith, R. L.,
"Color Removal from Kraft Mill Effluents by
Ultrafiltration," Environmental Protection
Technology Series, EPA-660/2-73-019, Office of
Research and Development, EPA, Dec. (1973).
286. Private Communication, Union Carbide Corp., S.
Charleston, W. Va. (1974).
617
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287. Rock, S. L., Kennedy, D. C., and Brunner, A.,
"Decoloration of Kraft Mill Effluents with
Polymeric Adsorbents," TfYPPI Environmental Conf. ,
Apr. 17-19 (197U) .
288. Anderson, L. G. , GrocHeval "I, r.. „ L^ndberg, S. , and
Phillips, Jr., "A New Color Removal Process: A
Field Report," TAPPI, 57, 4 .11974) .
289. Sanks, R. L, , "Ion Exchange Color and Mineral
Removal from Kraft Bleach Wastes," Environmental
Protection Technology Series, EPAR2-73-255, Office
of Research and Monitoring, EKA. May (1973) .
290. McGlasson, W. G., et al., "Treatment of Pulp Mill
Effluents with Activated Carbon," NCASI Bulletin
No_._ 199 (1967) .
291. Whittemore, R. C., "An Evaluation of the Adsorptive
Properties of Fly Ash and Bark -Derived Activated
Char," NCASI Technical Bulletin No. 267 (1973).
292. Hanzawa, M., et al., "Clarification of NSSC Waste
Liquor by Active Carbon, etc.," Res. Bull. Coll.
Exfit^ Forests Hokkaido Univ.(Jup.), 29, 361 (1972);
Abs. Bull Inst. Paper Chem., U3, 11803 (1973).
293. MacDonald, D. G., and Nguyen, T., "Activated Carbon
from Bark for Effluent Tref>.tmeutf" Pulp & Paper,
75, 5 (1974) .
294. Bauman, H. D., and Lutz, L, R., "Ozonation of a
Kraft Mill Effluent," TAPPI Environmental Conf.,
Apr. 17-19 (1974) .
295. Rapson, B., Sullivan, D= P., and Brothers, J. A.,
"NSRF SeawaterLime Clarification Process for Kraft
Effluents," Paper Trade Journal, Feb., 25 (1974).
296. "Color Removal Process," jPulg and Paper
International, May (1973).
297. Twitchell, J. P., and Edwards, L. L., "Kraft Mill
Material Balance CalculaLions for Brown Stock
Washing, Screening and Oxygen Bleaching," TAPPI
Environmental Conf. (1974),
298. Narrstrom, H., "The Environmental Care Project of
the Swedish Pulp and Paper Industry," TAPPI
Environmental Conf. (1974).
6)8
-------
299. Nichols, G. A., "Kraft Multistage Bleach Plant
Effluents," TAPPI, 56, 3 (1973).
300. Chen, H. T., et al., "Evaluation of Four Biological
Systems on Integrated Paper Mill Effluent," TAPPI
Environmental Conf. (1974).
301. Gillespie, W. J., et al., "A Pilot Scale Evaluation
of the Efficacy of Rotating Biological Surface
Treatment of Pulp and Paper Mill Wastes," TAPPI
Environmental Conf. (1974).
302. MaAliley, J. E., "A Pilot Plant Study of a Rotating
Biological Surface for Secondary Treatment of
Unbleached Kraft Mill Wastes," TAPPI Environmental
Conf. (1974) .
303. Gorham International Inc., Study of Solid Waste
Management Practices in the Pulp and Paper
Industry, EPA, Office of Solid Waste Management
Program, Feb. (1974).
304. Tyler, M. A., and Fitzgerald, A. D., "A Review of
Colour Reduction Technology in Pulp and Paper Mill
Effluents," Presented at the 58th Annual Meeting
Technical Section, CPPA, Montreal, Jan. 24-28
(1972) .
305. Vogt, C., 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
Point Source Category, U. S. Environmental
Protection Agency, EPA-440/ 1-74-025-a, May 1974.
306. TAPPI Mag., American Defibrator, Vol. 59, No. 2,
February 1976.
307. American Paper Institute, Comments Concerning
Effluent Limitations and Guidelines for Existing
Sources and Standards of Performance and
Pretreatment Standards for New Sources for The
Bleached Kraft, Groundwood, Sulfite, Soda, Deink,
and Non-Integrated Paper Mills Segment of the Pulp,
Paper, and Paperboard Point Source Category;
Federal Register, September, 5, 1975, Vol. 40, No.
173.
619
-------
308. Libby, Earl C.; Pulp and Paper Science and
Technology; Vol. I Pulp; McGraw - Hill Book Co.,
NY, NY. 1962.
309. Button, N.; ITT - Rayonier, Inc. Correspondence;
December 1975.
310. Clark, J. W. and Viessman, W., Jr., Water Supply
and Pollution Control, International Textbook
Company (1970) .
311. McKinney, R. E., Microbiology for Sanitary
Engineers, McGraw - Hill Book Company (1962).
312. Brock, T. D., Biology of_ Microorganisms^ Prentice-
Hall, Inc. (1970)
313. E. J. Kirsch, Private Communication, Purdue
University.
314. Metcalf & Eddy, Inc., Wastewater Engineering,
McGraw-Hill Book Company, Chapter 10 (1972).
315. Streeter, H. W. and Phelps, E. B., "A Study of the
Pollution and Natural Purification of the Ohio",
Public Health Bulletin 146, United States Public
Health Service, February (1925).
316. Vamvakias, J. G. and Miller, J. P., "Temperature
Response of Aerated Stabilization Basins With and
Without Nutrients," Fifth Paper—Industry and
Stream Improvement Conference, Canadian Pulp and
Paper Association, Technical Paper T87.
317. T. W. Beak Consultants Limited, "Biological
Treatment Study," Government of Canada, Ottawa,
Canada, September (1972) .
318. McKeown, J. J.; Buckley D. B.; and Gellman,
I., "A statistical Documentary on the Performance
of Activated Sludge and Aerated Stabilization Basin
Systems Operating in the Paper Industry," Purdue
Industrial Waste Conference XXIX (1974).
319. "A Manual of Practice for Biological Waste
Treatment in the Pulp and Paper Industry," NCASI
Technical Bulletin f214.
320. Burns, O. B., Jr. and Eckenfelder, W. W., Jr., "A
Statistical Study of Five Years' Operation of West
620
-------
Virginia Pulp and Paper Company1s Waste Treatment
Plant," Purdue Industrial Waste Conference XVIII
(1963) .
321. Dorr Oliver, Inc., Stamford, Connecticut.
322. American Water Works Association, Water Treatment
Plant Design, AWWA, Inc. (1969).
323. Ford, D. L.; Shin, C. S.; and Sebesta, E. C.,
"Temperature Prediction in Activated Sludge Basins
Using Mechanical Aerators," Purdue Industrial Waste
Conference XXVII (1972) .
324. Adams, C. E., Jr., et al, "The Development of
Design Criteria for Wastewater Treatment
Processes," Proceedings of a Seminar, Vanderbilt
University, April (1975).
325. Eckenfelder, W. W. and Ford, D. L., Water Pollution
Control, Jenkins Book Publishing Company (1970).
326. Babcock 6 Wilcox, Inc.; Personnel Communication.
327. TAPPI Mag.; Vol. 54, No. 4 Page 564.
328. Amberg, H. Crown Zellerbach Corp.; Correspondence,
Sept. 1975.
329. Brown, S., Philip, D.; "Color Removal from Bleached
Kraft Effluents." Dow Chemical Co.; Presented at
TAPPI Envir. Conference, May 1975.
330. Casey, J. P., Pulp and Paper Chemistry and Chemical
Technology, 2nd Ed., Interscience Publishers, Inc.,
New York (1960) .
331. Masak, E., Jr., "Production Hydrosulfite Bleaching
of Aspen Groundwood," Tappi 45, 1 (Jan., 1960).
332. Andrews, I. H., "Zinc Hydrosulphite Treatment of
Groundwood," Tappi Vol. 32, No. 6 (June 1949) .
333. Yankowski, A. A., "Brightneww Reversion of Zinc
Hydrosulfite Bleached Groundwood," Tappi, 40, 9
(Sept., 1957).
334. Barton, R. W., "Bleaching of Mechanical Pulp for
Moderate Brightness Increases with Zinc
Hydrosulfite, " Tappi, 46, 10 (Oct., 1963).
621
-------
335. Barton, R. W. and Atwood, H. S., "Role of Zinc
Hydrosulphite in the Paper Industry Today," Paper
Trade Journal, 146, 21 (May 21, 1962).
336. Betz, R. G. and Styan, G. E., "Brightening of
Douglas Fir Groundwood," Pulp Paper Mag, Can., 75,
C (March, 1974).
337. Sparrow, D. B. , "Bleaching Groundwood with
Hydrosulphite," Tappi, 39, 7 (July, 1956).
338. Fergusen, D. M., Hamilton, R. P., Armstrong, A. D.,
Rosebush, F. J., and Jordan, P. O., "Continuous
High Density Bleaching of Groundwood," Pulp Paper
Mag, Caru., (April, 1962) .
339. Richardson, C. A., "Multistage Bleaching of
Groundwood," Tappi, 39, 6 (June, 1956).
340. Comments by American Paper Institute (June 10,
1976).
341. Nekoose-Edwards, Correspondence; (June, 1975).
342. Industrial Waste Study of Paper and Allied Products
Industry prepared by Wapora, Inc., for EPA; (July,
1971) .
343. Process design Manual for Pollution Control in the
Pulp and Paper Industry, Vol. II, Water and Solids;
EPA Technology Transfer.
344. Consulting Engineer, "Cost Estimating by Use of the
Six-Tenths Factor", John D. Constance, Pg. 84,
September 1974.
345. NCASI Special Report No. 75-02, "A Survey of Pulp
and Paper Industry Environmental Protection
Expenditures and operating costs; June, 1975.
346. Daniels, Dr. Stacy L., "Removal of Heavy Metals by
Iron Salts and Polyelectrolyte Flocculants,"
Environmental Control Systems, Dow Chemical,
Presented at the 75th National Meeting of American
Institute of Chemical Engineers in Detroit,
Michigan, June 6, 1973.
347. "Zinc Precipitation and Recovery from Viscose Rayon
Wastewater," WPRCS 12090ESG 01/71, EPA Water
Quality Office.
622
-------
348. Stone, E. H. F., "Treatment of Non-Ferrous Metal
Process Waste at Kynoch orks, Birmingham, England,"
22nd Annual Industrial Waste Conference, Purdue
University, Lafayette, Indiana, 848, (1967).
349. Correspondence with Weyerhauser Corp.; June, 1976.
623
-------
SECTION XII
GLOSSARY
Active alkali
A measure of the strength of alkaline pulping liquor
indicating the sum of caustic sooa and sodium sulfide
expressed as Na20.
Air Dry (AD) Ton
Measurement of production including a moisture content of 10
percent by weight.
Bark
The protective covering of a tree.
Barking
Removal of bark from logs in a wet or dry process.
Black Liquor
Spent liquor recovered from a kraft digester up to the point
of its introduction into the recovery plant.
Bleaching
The brightening and delignification of pulp by addition of
chemicals such as chlorine.
Blow
Ejection of the chips from a digester.
Boil-Out
A procedure, usually utilizing heat and chemicals, to clean
equipment such as evaporators, heat-exchangers, and
pipelines.
Breaker stack
Two rolls, one above the other, placed in the dryer section
of a paper machine to compact the sheet and smooth out its
surface defects.
625
-------
Broke
Partly or completely manufactured paper that does not leave
the machine room as salable paper or board; also paper
damaged in finishing operations such as rewinding rolls,
cutting, and trimming.
Calender Stack
Two or more adjacent and revolving rolls which provide even
caliper control of the sheet and the final finishing of its
surface.
Cellulose
The fibrous constituent of trees which is the principal raw
materials of paper and paperboard.
Chest (or Stock Chest)
Tank used for storage of wet fiber or furnish.
Chips
Small pieces of wood used to make pulp.
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 dissolving lignin and other
nonfibrous constituents.
Cooking Liquor
The mixture of chemicals and water used to dissolve lignin
in wood chips.
626
-------
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 pulpr and to thicken pulp consistency.
Digester
A pressure vessel used to cook wood chips in the presence of
cooking liquor and heat.
Digestion
Cooking of chips in the above manner.
Dregs
The inert rejects from the green liquor clarifier of a pulp
mill.
Extraction Water
Water removed during a pulp manufacturing process.
Felt
The endless belt of wood or plastic used to convey and
dewater the sheet during the papermaking process.
Fiber
The cellulosic portion of the tree used to make pulp, paper,
and paperboard.
Fines
Fiber fragments produced by fiber cutting in beaters.
Furnish
The mixture of fibers and chemicals used to manufacture
paper.
627
-------
Gland
A device utilizing a soft wear-resistant material used to
minimize leakage between a rotating shaft and the stationary
portion of a vessel such as a pump.
Gland Water
Water used to lubricate a gland. Sometimes called "packing
water."
Grade
The type of pulp or paper product manufactured.
Green Liquor
Liquor made by dissolving chemicals recovered from the kraft
process water and weak liquor preparatory to causticizing.
Grits
Unreactive materials mechanically removed from the
causticizing of kraft and soda green liquor and disposed of
as solid waste.
Headbox
The area of the paper machine from which the stock flows
through a sluice onto the wire.
Integrated
A term used to describe a pulp and paper mill operation in
which all or some of the pulp is processed into paper at the
mill.
Lignin
A non-degradable organic compound of wood.
Newsprint
Paper made largely from groundwood pulp, with a small
percentage of chemical pulp added for strength, used chiefly
in the printing of newspapers.
Packing Water
See Gland Water.
628
-------
Prehydrolysi s
Pre-steaming of chips in the digester prior to cooking;
usually associated with improved bleaching of kraft pulp.
Pulp
Cellulosic fibers after conversion from wood chips.
Pulper
A mechanical device resembling a large-scale kitchen blender
used to separate fiber bundles in the presence of water
prior to papermaking.
629
-------
Ray Cells
Cells which carry stored food (protein, starch, and fats)
from the bark to the wood of a tree and appear as impurities
in the pulping process, especially unbleached operations.
Rejects
Material unsuitable for pulp or papermaking which has been
separated in the manufacturing process.
Save-all
A mechanical device used to recover papermaking fibers and
other suspended solids from a waste water or process stream.
Screenings
Rejects separated from useable pulp by a device such as a
screen.
Side-Hill Screens
Steeply sloped, 60-mesh screens.
Spent Cooking Liquor
Cooking liquor after digestion 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.
630
-------
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.
631
-------
1 Stainless Steel
1 Stainless Steel is steel with the following composition:
Carbon 0.08 percent maximum
Manganese 2.00 percent maximum
Silicon 1.00 percent maximum
Chromium 18.00-20.00 percent
Nickel 11.00-10.00 percent
Molybdenum 3.00- U.QQ percent
Remainder Iron
Virgin wood Pulp (or fiber)
Pulp made from wood, as contrasted to waste paper sources of
fiber.
Wet Laps
Rolls or sheets of pulp of 30-45 percent consistency
prepared in a process similar to papermaking; facilitates
transportation of market pulp.
Wet Strength Additives
Chemicals such as urea and melanine formaldehydes used in
papermaking to impart strength to papers used in wet
applications.
White Liguor
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.
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.
632
-------
A.
A.
AD Pulp
ADT
APHA
API
APS
ASB
atm
AWT
B.
BATEA
BCT
BK
BOD or BOD5
BPCTCA
BTU
C
c
°c
C+F
CMN
SECTION XIII
TERMINOLOGY INDEX
Activated Sludge
When associated with a mill code, refers to new data
Air Dried Pulp
Air dry tons
American Public Health Association
American Paper Institute
anti-pollution sequence
Aerated Stabilization Basin
atmospheres
Advanced Waste Treatment
Board or Paperboard
Best Available Technology Economically Achievable
Paperboard, coarse. Tissue
Bleached Kraft
Biochemical Oxygen Demand (five-day)
Best Practicable Control Tehcnology Currently
Available
British Thermal Units
Clarifier
Coarse
degrees Centigrade
Clays and Fillers
Coarse, Molded, Newsprint
633
-------
CMP
COD
cu m/min
cu. m./kkg
D
DAF
Diss.
«.
DO
E. Coli.
ENR
F
FACET
OF
Fwp
"G"
gal
gpd/sq. ft..
gpm
GW
ha
hp
IDOD
IJC
in. Hg
JTU
Chemi-mechanical Pulp
Chemical Oxygen Demand
Cubic meters per minute
Cubic meters per 1000 kilograms
De-ink
Dissolved Air Flotation
Dissolving
Dissolved Oyxgen
Escherica Coliform
Engineering News Record
Fine
Fine Activated Carbon Effluent Treatment
degrees Fahrenheit
from waste paper
Gravity
gallons
gallons per day per square foot
gallons per minute
Groundwood
hectare, 10,000 meter squared
horsepower
Immediate Dissolved Oxygen Demand
International Journal commission
inches of Mercury
Jackson Turbitity Units
634
-------
kg
kg BOD/kg
MLUSS/day
kg/ha sur-
face area/
day
kg/kkg
kg/sq cm
kgal
kgal/ton
kkg
kw
L
Lpd/sq. m.
L/kkg
L/min.
Liquor
Recovery
Ib
Ib/ac/day
mgd
mg/1
MKT
MLSS
MLVSS
MM
kilogram, 1000 grams
kilogram of BOD per kilograms of MLVSS per day
kilograms per hectare of surface area per day
kilograms per 1000 kilograms
kilograms per square centimeter
1000 gallons
1000 gallons per ton
1000 kilograms, metric ton
kilowatt
liter
liters per day per square meter
liters per 1000 kilograms
liters per minute
C - Collected
B - By-products
I - Incinerated
pound
pound per acre per day
million gallons per day
milligrams per liter
market
Mixed Liquor Suspended Solids
Mixed Liquor Volatile Suspended Solids
Maximum Month
635
-------
nm
N
N (NSM)
N.A.
NAB
NCASI
NI
nm
NOV
NPDES
NSPS
NSSC
P
PCB
PCU
PP
ppm
PS
psig
RBS
rpm
RWL
S
SB
millimicrons
News
non-standard methods when associated with
data
Not Available
Natural Aeration Basin
National Council for Air and Stream Improvement
Non-Integrated
nano meters, 10- meters
Number of Values Reported
National Pollutant Discharge Elimination
System
New Source Performance Standards
Neutral Sulfite Semi-chemical
Pulp
Polychlorinated biphenyl
Platinum Color Units
Purchased Pulp
parts per million
Post Storage
pounds per square inch gage
Rotating Biological Surface
revolutions per minute
Raw Waste Load(s)
Sulfite
Settling Basin
636
-------
Set Slds
SO
SSL
Std. Meth.
T
TAPPI
TC
TDS
Temp
TMP
TOC
TOD
TOM
ton
tpd
TS
TSS
turbid
TVS
Type
Condenser
UK
Settleable Solids
Soda
Spent Sulfite Liquor
Standard Methods
Tissue
Technical Association of the Pulp
and Paper Industry
Total Carbon
Total Dissolved Solids
Temperature
Thermo-mechanical Pulp
Total Organic Carbon
Total Oxygen Demand
Total Otganic Matter
1000 pounds (short ton)
tons per day
Total Solids
Total Suspended Solids
Turbitity
Total Volatile Solids
V - Vapor Recompression
S - Surface Condenser
B - Barometric Condenser
Unbleached Kraft
637
-------
Table 154
CO
00
ID
o
o
o
Convcrsior. Table
MULTIPLY (ENGLISH UNITS)
English Unit
acre
acre - feet
British Thermal Unit
British Thermal L'r.it/pound
cubic fcet/rinutp
cubic feet/second
cubic feet
cubic fe^'t
cubic inches
degree Fahrenheit
feet
gallon
gallon/minute
horse cov;cr
inches
inches of mercury
pounds
niliicn gallons/cay
rile
pcund/scuare inch (gauge)
square feet
square inches
tor. s (short;
yard
* Actual conversion, not a
by
Abbreviation Conv rsion
ac
ac ft
3TU
BTU/lb
cfm
cfs
cu -ft
cu ft
cu in
T
ft
gal
apn
hp
ir.
in Kg
Ib
mgd
mi
psic
sq ft
sq : p.
' on
yd
nul t ipl i er
0.
1233.
0.
0.
0.
1.
0.
28.
16.
0.55f> (
0.
3.
0.
.0.
^
s. .
0.
0.
3733
\ ,
405
5
252
555
lit?:
7
028
i ^
j'.<
T-32)*
30/.3
7S5
06. U
7 « H 7
5 'i
03:42
45 ;
609
(0.00305 psiQ + D*
0.
6.
0.
0.
0929
1*1 !
1 -•' ^.
9 0 V
9 i .'- 4
TO OBTAIN (METRIC UNITS)
Abbreviation Metric Unit
ha
cu m
Xg 'cal
kg cal/Xq
CL: ,T/r.in
cu m/!nin
cu rr.
X
cu cm
°C
m
1
1/scc
kv
C"
atF.
kq
cu n/d.iy
kr
atr.
sq m
sq err
Xkg
m
hectares
cubic meters
kilogram - calories
kilogram calor ies/kilcgrarr.
cubic meters/minute
cubic meters/minute
cubic p.etcrs
liters
cubic centimeters
degree Centigrade
m(. tcrs
1 i ters
1 j ters/Eecond
-------
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON. D.C. 20460
WH 552
POSTAGE AND FEES PAID
ENVIRONMENTAL PROTECTION AGENCY
EPA-335
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