Development Document for Effluent Limitations Guidelines
and New Source Performance Standards for the
MAJOR INORGANIC PRODUCTS
Segment of the
Inorganic Chemicals Manufacturing
Point Source Category
MARCH 1974
US- ENVIRONMENTAL PROTECTION AGENCY
Washington, D.C. 20460
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DEVELOPMENT DOCUMENT
for
EFFLUENT LIMITATIONS GUIDELINES -
and
NEW SOURCE PERFORMANCE STANDARDS
for the
MAJOR INORGANIC PRODUCTS SEGMENT OF THE
INORGANIC CHEMICALS MANUFACTURING
POINT SOURCE CATEGORY
Russel Train
Administrator
Roger Strelow
Acting Assistant Administrator for Air & Water'Programs
Allen Cywin
Director, Effluent Guidelines Division
Elwood E. Martin
Project Officer
March, 1974
Effluent Guidelines Division
Office of Air and Water Programs
U.S. Environmental Protection Agency
Washington, D.C. 20460
For Mda by tlu Superintendent of poounwiti, U.S. QoTtmnitnt Printing Offle*, Washington, D.C. 30*02 - Prtw 13.60
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ABSTRACT
This document presents the findings of an extensive study of
major inorganic chemicals manufacture for the purpose of
developing effluent limitation guidelines for existing point
sources and standards of performance and pretreatment standards
for new sources to implement Sections 304, 306 and 307 of the
Federal Water Pollution Control Act, as amended (33 U.s.c. 1551,
131U, and 1316, 86 Stat. 816 et. seg.)(the "Act").
Effluent limitations guidelines contained herein set forth the
degree of effluent reduction attainable through the application
of the best practicable control technology currently available
and the degree of effluent reduction attainable through the
application of the best available technology economically
achievable which must be achieved by existing point sources by
July 1, 1977 and July lr 1983, respectively. The standards of
performance and pretreatment standards for new sources contained
herein set forth the degree of effluent reduction which is
achievable through the application of the best available
demonstrated control technology, processes, operating methods, or
other alternatives,
Based on the application of best practicable technology currently
available 12 of the 22 chemicals under study can be manufactured
with no discharge of process waste water pollutants to navigable
waters. With the best available technology economically
achievable 20 chemicals can be manufactured with no discharge of
process waste water pollutants to navigable waters. NO discharge
of process waste water pollutants to navigable waters is required
as a new source performance standard for all chemicals except
titanium dioxide, chlorine, sodium dichromate, sodium sulfite and
sodium chloride.
Supporting data and rationale for development of the effluent
limitations guidelines and standards of performance are contained
in this report.
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CONTENTS
Section Page
I CONCLUSIONS 1
II RECOMMENDATIONS 3
III INTRODUCTION 5
IV , INDUSTRY CATEGORIZATION 61
V WATER USE AND WASTE CHARACTERIZATION 65
VI SELECTION OF POLLUTION PARAMETERS 133
VII CONTROL AND TREATMENT TECHNOLOGY 189
VIII COST, ENERGY AND NON-WATER QUALITY 229
ASPECTS
IX EFFLUENT REDUCTION ATTAINABLE THROUGH 313
THE APPLICATION OF THE BEST PRACTICABLE
CONTROL TECHNOLOGY CURRENTLY AVAILABLE,
EFFLUENT GUIDELINES AND LIMITATIONS
X EFFLUENT REDUCTION ATTAINABLE THROUGH 331
THE APPLICATION OF THE BEST AVAILABLE
TECHNOLOGY ECONOMICALLY ACHIEVABLE,
EFFLUENT GUIDELINES AND LIMITATIONS
XI NEW SOURCE PERFORMANCE STANDARDS AND 339
PRETREATMENT RECOMMENDATIONS
XII ACKNOWLEDGEMENTS 343
XIII REFERENCES 345
XIV GLOSSARY 351
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LIST OF FIGURES
Figure Page
1 Standard Aluminum Chloride Flow Diagram 12
2 Standard Process Diagram for Aluminum Sulfate 14
Manufacture
3 Standard Calcium Carbide Flow Diagram 15
4 Standard Process for Calcium Chloride Manufacture 16
5 Calcium Oxide (Lime) Flow Diagram 18
6 Standard Chlorine - Caustic Soda Flow Diagram - 20
Diaphragm cell Process
7 Standard Chlorine - Caustic Flow Diagram Mercury 21
Cell Process
8 Standard Hydrochloric Acid Flow Diagram (Synthetic 24
Process)
9 Hydrofluoric Acid Flow Diagram 25
W Standard Hydrogen Peroxide Electrolytic Process 27
Flow Diagram
11 Standard Hydrogen Peroxide Flow Diagram 29
(Riedl-Pfleiderer Process)
12 Standard Nitric Acid Process Flow Diagram 30
13 Commercial Extraction of Potassium 32
14 Standard Potassium Dichromate Process Flow Diagram 33
15 Standard Potassium Sulfate Process Diagram 35
16 Standard Sodium Bicarbonate Process Flow Diagram 36
17 Solvay Process Sodium Carbonate Flow Diagram 38
18 Standard Solar Salt Process Flow Diagram 40
19 Standard Multiple-Effect Evaporation Sodium Chloride 42
Process Flow Diagram
VI
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Figure Page
20 Standard Sodium Dichromate Process Diagram 44
21 Standard Chlorine-Sodium Downs Cell Process Flow 46
Diagram
22 Standard Liquid Sodium Silicate Flow Diagram 48
23 Standard Anhydrous Sodium Metasilicate Flow Diagram 49
24 Standard Sodium Sulfite Process Flow Diagram 50
25 Sulfuric Acid Plant Double Absorption 53
26 Standard Sulfuric Acid Single Absorption Flow , 54
Diagram (Contact Process)
27 Standard Chloride Process Titanium Dioxide Flow 56
Diagram
28 Standard Sulfate Process Titanium Dioxide Flow Diagram 58
29 Industry Categorization of Inorganic Chemicals 64
Manufacturing
30 Scrubber System for Treatment of Aluminum Chloride 69
Wastes at Plant 125
31 Aluminum Sulfate Process and Treatment Flow Diagram at 71
Plant 063
32 Aluminum Sulfate Process and Treatment Flow Diagram at 72
Plant 049
33 Calcium Carbide Process Flow Diagram at Plant 190 74
34 Water Usage at Plant 190 Calcium Carbide Facility 76
35 Calcium Chloride Flow Diagram at Plant 185 78
36 Flow Diagram for Lime Plant 007 81
37 Mercury Cell Flow Diagram (KOH) at Plant 130 84
38 Histogram of Mercury Discharges From Plant 144 87
VII
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F1gure Page
39 Mercury Abatement System at Plant 130 89
40 Diaphragm Cell Chior-Alkali Process at Plant 057 96
41 Sodium Hydroxide Concentration Facility at Plant 057 97
42 Startup Waste Treatment System at Plant 121 101
43 Hydrofluoric Acid Process Flow Diagram of Plant 152 105
44 Effluent Recycle System at Plant 152 106
45 Hydrogen Peroxide Process Diagram for Plant 069 111
46 Schematic Showing Waste Sources and Discharge at 114
Plant 100
47 Nitric Acid Process Flow Diagram for Plant 114 121
48 Potassium Sulfate Process Diagram at Plant 118 125
49 Solvay Sodium Bicarbonate Process Flow Diagram at 128
Plant 166
50 Solvay Soda Ash Process Flow Diagram at Plant 166 132
51 Calcium Chloride Recovery Process at Plant 166 135
52 Chromate Manufacturing Facility at Plant 184 144
53 Waste Treatment on Downs Cell at Plant 096 150
54 Sodium Silicate Manufacture at Plant 072 155
55 Sodium Sulfite Process Flow Diagram at Plant 168 157
56 Double Absorption Contact Sulfuric Acid Process 162
Flow Diagram at Plant 086
57 Titanium Tetrachloride Portion of Titanium Dioxide Plantl66
58 Titanium Dioxide Portion of Plant (Chloride Process) 167
59 Treatment, Titanium Tetrachloride of Plant 009 169
60 Treatment, Titanium Dioxide Portion of Plant 009 170
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Figure page
61 Sul'fate Process Flow Diagram at Plant 122 176
62 Model for Water Treatment and Control System 234
Inorganic Chemicals Industry
63 Model for Water Treatment System Inorganic Chemicals 235
Industry
64 Capital Costs for Small Unlined Ponds (Reference 277
(28), (29), and (30))
65 Capital Costs for Large Unlined Ponds (Reference (27)) 277
66 Construction Cost of Small Lined Ponds (Reference (30)) 279
67 Capital Costs for Large Lined Ponds 279
68 Installed Capital Cost for Carbon Adsorption Equipment 280
69 Overall Costs for Carbon Adsorption 280
70 Installed Capital Cost vs. Capacity for 283
Demineralization
71 Chemical Costs for Demineralization 283
72 Installed Capital Costs for Reverse Osmosis Equipment 287
73 Costs for Reverse Osmosis Treatment 287
74 Trade-off Between Membrane Permeability (Flux) and 288
Selectivity (Rejection and Product Water Quality) for
Cellulose Acetate Base Membranes (10 MGD Plant
@55% Recovery, 3100 ppm TDS Feed)
75 Energy Comparison for Dissolved Solids Removal 292
76 Installed Capital Costs vs. Capacity for High 295
Efficiency VTE or Multi-State Flash Evaporators
77 Overall and Total Operating Costs for VTE and 295
Multi-Flash Evaporators
78 Capital Costs vs. Effects for Conventional Multi-Effect 296
Evaporators
79 Steam Usage vs. Effects for Conventional Multi-Effect 297
Evaporators
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Page
Correlations of Equipment Cost with Evaporator Heating 298
Surface
81 Overall Costs for 6-Effect Evaporator Treatment of 298
Waste Water
82 Disposal Costs for Sanitary Landfills 304
83 Treatment Applicability to Dissolved Solids Range in 308
Waste Streams
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I
LIST OF TABLES
TABLES PAGE
1 Effluent Limitation Guidelines and New Source 4
Performance Standards
2 U. S. Production of Inorganic Chemicals (Metric 11
Tons)
3 Plant Effluent from CaC2_ Manufacture (All units ppm 77
unless specified)
4 Plant 185 Water Flows 80
5 Raw Waste Loads from Mercury Cell Process (All Amounts 85
in kg/kkg of Chlorine)*
6 Monthly Mercury Abatement System Discharge During 1972 90
at Plant 130
7 Plant 130 Effluent Data 91
8 Measurments of the Effluents From Plant 130 92
9 Plant 144 Intake Water 93
10 Plant 144 Effluent Data 94
11 Intake Water and Raw Waste Composition Data at 108
Plant 152
12 Comparison of Plant Intake Water and Cooling Water 109
Discharge at Plant 152
13 Plant 069 Process Water Effluent After Treatment 113
14 Raw Waste Loads at Plant 100 115
15 Effluent Treatment Data for Plant 100 117
16 Composition of Plant 100 Effluent Streams After 118
Treatment
17 Plant 100 Water Intake and Final Effluent Verification 119
Measurements
XI
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TABLES PAGE
18 Plant 166 Verification Data 131
19 Calcium Chloride Recovery Process 137
20 Verification Measurements at Plant 166 138
21 Chemical Analysis of Bittern 140
22 Verification Measurements at Plant 030 143
23 Intake and Effluent Composition at Plant 184 147
24 Analysis of River Water at Plant 184 148
25 Analysis of Waste Treatment Streams at Plant 184 149
26 Plant 096 Effluent 152
27 Plant 096 Effluent 153
28 Measurements of Plant 168 Process Waste Streams Before 159
and After Treatment
29 Plant 168 Cooling Water Measurements 160
30 Intake and Effluent Measurements at Plant 086 164
31 In-Plant Water Streams at Plant 141 165
32 Composition of Plant 009 Effluent Streams After Treatment 171
33 Verification Data of Plant 009 172
34 Sulfate Process Waste Streams — Titanium Dioxide Manufacture 174
35 Typical Ore Analyses - Titanium Dioxide Manufacture 175
36 Future Treatment at Plant 122 178
37 Partial Discharge Data from T102_Sulfate Plants (1) 179
38 Summary of BPCTCA and BATEA 190
39 Typical Water-Borne Loads for Inorganic Chemicals of this 208
study
40 Raw Water and Anticipated Analyses After Treatment 216
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PAGE
Water Quality Produced by Various Ion Exchange Systems 219
Special Ion Exchange Systems 220
Summary of Cost and Energy Information for Attainment of 230
Zero Discharge
44 Water Effluent Treatment Costs 236
Inorganic Chemicals
Chemical: Aluminum Chloride (22.5 kkg/day (25 tons/day)
Capacity)
45 Water Effluent Treatment Costs 238
Inorganic Chemicals
Chemical: Aluminum Sulfate (36kkg/day (40 tons/day) Capacity)
46 Water Effluent Treatment Costs 239
Inorganic Chemicals
Chemical: Calcium Carbide (127 kkg/day (140 tons/day)
Capacity)
47 Water Effluent Treatment Costs 241
Inorganic Chemicals
Chemical: Lime - Air Pollution Costs only (281 kkg/day
(310 tons/day) Capacity)
48 Water Effluent Treatment Costs 242
Inorganic Chemicals
Chemical: Calcium Chloride (450kkg/day (500 tons/day)
Capacity)
49 Water Effluent Treatment Costs 243
Inorganic Chemicals
Chemical: Mercury Cell Chlor-Alkali (158 kkg/day (175 tons/day)
Capacity)
50 Water Effluent Treatment Costs 244
Inorganic Chemicals
Chemical: Diaphragm Cell, Chlor-Alkali (1810 kkg/day
(2000 ton/day) Capacity)
51 Water Effluent Treatment Costs 246
Inorganic Chemicals
Chemical: Hydrochloric Acid (36 kkg/day (40 tons/day) Capacity)
52 Water Effluent Treatment Costs 247
Inorganic Chemicals
Chemical: Hydrofluoric Acid (36 kkg/day (40 tons/day) Capacity)
Kill
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TABLES PAGE
53 Water Effluent Treatment Costs 249
Inorganic Chemicals
Chemical: Hydrogen Peroxide (Organic Process) (85 kkg/day
(94 tons/day) Capacity)
54 Water Effluent Treatment\Costs 250
Inorganic Chemicals
Chemical: Hydrogen Peroxide - Electrolytic (12 kkg/day
(13.2 ton/day) Capacity)
55 Water Effluent Treatment Costs 252
Inorganic Chemicals
Chemical: Potassium Chromate (13.5 kkg/day (15 tons/day)
Capacity)
56 Water Effluent Treatment Costs 253
Inorganic Chemicals
Chemical: Potassium Sulfate (454 kkg (500 tons) per day
Capacity)
57 Water Effluent Treatment Costs 254
Inorganic Chemicals
Chemical: Sodium Bicarbonate (272 kkg/day (300 tons/day)
Capacity)
58 Water Effluent Treatment Costs 257
Inorganic Chemicals
Chemical: Soda Ash (2520 kkg/day (2800 tons/day) Capacity
59 Water Effluent Treatment Costs 258
Inorganic Chemicals
Chemical: Solar Salt (2540 kkg/day (2800 tons/day)
Capacity)
60 Water Effluent Treatment Costs 259
Inorganic Chemicals
Chemical: Sodium Chloride (Brine/Mining) (1000 kkg/day
(1100 ton/day) Capacity
61 Water Effluent Treatment Costs 261
Inorganic Chemicals
Chemical: Sodium Bichromate (149 kkg/day (164 tons/day)
Capacity)
62 Water Effluent Treatment Costs 262
Inorganic Chemicals
Chemical: Sodium Metal (58 kkg/day (65 tons/day) Capacity
xiv
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TABLES PAGE
63 Water Effluent Treatment Costs 264
Inorganic Chemicals
Chemical: Sodium Silicate (72 kkg/day (80 tons/day)
Capacity)
64 Water Effluent Treatment Costs 265
Inorganic Chemicals
Chemical: Sodium Sulfite (45 kkg/day (50 ton/day) Capacity)
65 Water Effluent Treatment Costs 267
Inorganic Chemicals
Chemical: Sulfuric Acid (Sulfur Burning)(360 kkg/day
(400 tons/day) Capacity)
66 Water Effluent Treatment Costs 268
Inorganic Chemicals
Chemical: Titanium Dioxide (Chloride Process),
67 kkg (74 ton) per day basis
67 Water Effluent Treatment Costs 270
Inorganic Chemicals
Chemical: Titanium Dioxide (Sulfate Process), 108 kkg
(120 ton) per day basis
68 Water Effluent Treatment Costs (Acid Recovery Option) 271
Inorganic Chemicals
Chemical: Titanium Dioxide (Sulfate Process), 108 kkg
(120/ton) per day basis
69 Comparison of Chemicals for Waste Neutralization 275
70 Capital Costs for Lined Solar Evaporation 281
Ponds as a Function of Capacity
71 Costs for Solar Evaporative Pond Disposal 281
72 Overall Costs for Demineralization 285
73 Overall Costs for Demineralization 286
74 Reverse Osmosis — Membrane Replacement Costs 289
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TABLES PAGE
75 Reverse Osmosis — Operating Costs 289
76 tvaporator Characteristics 291
77 Cost Estimates for Different Treatment 309
78 Model Treatment Plant Calculations Design and Cost Basis 310
XVI
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SECTION I
CONCLUSIONS
For the purpose of establishing effluent limitation guidelines
and standards of performance, the major inorganic products
segment of the inorganic chemicals manufacturing point source
category was divided into 22 product subcategories consistent
with the chemical produced. In some cases, the product
sutcategory was further subdivided to reflect different
manufacturing processes used to produce the same chemical. This
method of categorization reflects differences in the nature of
raw wastes generated in the manufacture of different chemicals,
as well as its treatability. Factors such as plant age, plant
size and geographical location did not justify further
segmentation of the industry.
Based on best practicable control technology currently available
(EPCTCA), 12 of the 22 chemicals under study can be manufactured
with no discharge of process waste water pollutants to navigable
waters. With the application of best available technology
economically achievable (BATEA), 20 of the 22 chemicals can be
manufactured with no discharge of process waste water pollutants
to navigable waters. No discharge of process waste water
pollutants to navigable waters is, also, achievable as a new
source performance standard (NSPS) based on the best demonstrated
control technologies, processes, operating methods or other
alternatives (BDCT) for all chemicals except titanium dioxide,
chlorine, sodium dichromate, sodium sulfite, and sodium chloride.
This study included 22 of the major inorganic chemicals of SIC
categories 2812, 2816, and 2819 which discharge significant
quantities of process waste water pollutants into the navigable
waters of the United States. A forthcoming study includes
certain other inorganic chemicals and industrial gases whose
annual U.S. production volume exceeds 450 kkg (500 ton) with
significant waste discharge potential.
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. SECTION II
RECOMMENDATIONS
The effluent limitation guidelines representing the effluent
reduction attainable by the application of best practicable
control technology currently available and the effluent reduction
attainable by the application of best available technology
economically achievable are shown in Table 1. Also shown are the
new source performance standards for each chemical subcategcry.
The figures in the table represent the thirty-day average
allowable discharge. In all cases the daily maximum is twice the
thirty-day average. All process waste water discharges must be
within the pH range of 6.0 - 9.0. Effluent limitation guidelines
for non-contact cooling water and waste streams resulting from
steam and water supply are being developed in a separate study.
The technologies on which such guidelines are based are discussed
in detail in Sections III - XI, along with the rationale for
selecting the various levels of technology.
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Table 1. EFFLUENT LIMITATION GUIDELINES
AND NEW SOURCE PERFORMANCE STANDARDS
Product Suhcategory
Limitation based on I1PCTCA (kg/kkg)
[.imitation based on liATEA Ug/kkg) Hew Source Performance Standard !kg/kkg)
Aluminum Chloride
Aluminum Sulfate
Calcium Carbide
. Calcium Chloride
Calcium Oxide and Hydroxide
Chlorine
a) mercury cell orocess
b) diaphragm cell process
Hydrochloric Acid
Hydrofluoric Acid
Hvdroqen Peroxide
a) organic process
b) electrolytic process
Ilitric Ac1
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SECTION III
INTRODUCTION
PUBPOSE ANC AUTHORITY
The United States Environmental Protection Agency (EPA) is
charged tinder the Federal Water Pollution Control Act Amendments
of 1972 with establishing effluent limitations which must be
achieved by point sources of discharge into the navigable water
of the United States.
Section 301(b) of the Act requires the achievement, by not later
than July 1, 1977, of effluent limitations for point sources,
other than publicly owned treatment works, which are based on the
application of the best practicable control technology currently
available as defined by the Administrator pursuant to Section
304(b) of the Act. Section 301 (b) also requires the achievement
by not later than July 1, 1983, of effluent limitations for point
sources, other than publicly owned treatment works, which are
based on the application of the best available technology
economically achievable which will result in reasonable further
progress toward the national goal of eliminating the discharge of
all pollutants, as determined in accordance with regulations
issued by the Administrator pursuant to Section 304 (b) of the
Act. Section 306 of the Act requires the achievement by new
sources of a Federal standard of performance providing for the
control of the discharge of pollutants which reflects the
greatest degree of effluent reduction which the Administrator
determines to be achievable through the application of the bes;t
available demonstrated control technology, processes, operating
methods, or other alternatives, including, where practicable, a
standard permitting no discharge of pollutants. Section 304(b)
of the Act requires the Administrator to publish within one year
of enactment of the Act, regulations providing guidelines for
effluent limitations setting forth the degree of effluent
reduction attainable through the application of the best
practicable control technology currently available and 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 regulations
proposed herein set forth effluent limitations guidelines
pursuant to Section 304 (b) of the Act for the inorganic chemicals
manufacturing point source category.
Section 306 of the Act requires the Administrator, within one
year after a category of sources is included in a list published
pursuant to Section 306(b) (1) (A) of the Act, to propose
regulations establishing Federal standards of performance for new
sources within such categories. The Administrator published in
the Federal Register of January 16, 1973 (38 F.R. 1624), a list
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of 27 point source categories. Publication of the list
constituted announcement of the Administrator1s intention of
establishing, under section 306, standards of performance
applicable to new sources within the inorganic chemicals
manufacturing point source category, which was included within
the list published January 16, 1973.
SUMMARY OF METHODS USED FOR DEVELOPMENT
GUIDELINES AND STANDARDS OF PERFORMANCE
OF EFFLUENT LIMITATION
The Environmental Protection Agency has determined that a
rigorous approach including plant surveying and verification
testing is necessary for the development of effluent standards
for industrial sources. A systematic approach to develop the
required guidelines and standards includes the following:
(a) Categorization of the industry and determination of
those industrial categories for which separate
effluent limitations and standards need to be set;
(b) Characterization of the waste loads resulting from
discharges within industrial categories and sub-
categories;
(c) Identification of the range of control and
treatment technology within each industrial
category and subcategory;
(d) Identification of those plants employing the best
practical technology currently available (ex-
emplary plants) ; and
(e) Generation of supporting verification data for
the best practical technology including actual
sampling of plant effluents by field teams.
The culmination of these activities is the development of the
guidelines and standards based on the best practicable technology
currently available.
This report describes the results obtained from application of
the abcve approach to the inorganic chemicals industry. Thus,
the survey and testing covered a wide range of processes,
products, and types of wastes. Studies of a total of twenty-five
chemicals listed below are summarized in this Document.
Selected Inorganic Chemicals
Aluminum Chloride
Aluminum Sulfate
Calcium Carbide
Calcium Chloride
Chlorine
Hydrochloric Acid
Hydrogen Peroxide
Potassium Sulfate
Sodium Bicarbonate
Sodium Carbonate (Soda Ash)
Sodium Chloride
Sodium Dichromate
Sodium Hydroxide
Sodium Metal
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Hydrofluoric Acid Sodium Silicate
Calcium Oxide and Calcium Sodium Sulfate
Hydroxide
Nitric Acid Sodium Sulfite
Potassium Chromates Sulfuric Acid
Potassium Hydroxide Titanium Dioxide
Potassium Metal
The effluent limitation guidelines for existing point sources and
standards of performance for new facilities were developed in the
following manner. The point source category was first
categorized for the purpose of determining whether separate
limitations and standards are appropriate for different segments
within a pcint source category. Such subcategorization was based
upon raw material used, product produced, manufacturing process
employed, and other factors. The raw waste characteristics for
each sutcategory were then identified. This included an analysis
of (1) the source and volume of water used in the process
employed and the sources of waste and waste waters in the plant;
and (2) the constituents of all waste waters which result in
degradation of the receiving water. The constituents of waste
waters which should be subject to effluent limitations guidelines
and standards of performance were identified.
The full range of control and treatment technologies existing
within each subcategory was identified. This included an
i dentif ication of each control and treatment technology,
including both inplant and end-of-process technologies, which are
existent or capable of being designed for each sufccategory. It
also included an identification of the quantity of constituents
(including thermal) and the characteristics of pollutants
resulting from the application of each of the treatment and
control technologies. The problems, limitations and reliability
of each treatment and control technology were also identified.
In addition, the non-water quality environmental impact, such as
the effects of the application of such technologies upcn other
pollution problems, including air, solid waste, noise and
radiation were also identified. The energy requirements of each
of the control and treatment technologies were identified as well
as the cost of the application of such technologies.
Cost information contained in this report was obtained directly
from industry during exemplary plant visits, from engineering
firms and equipment suppliers, and from the literature. The
information obtained from the latter three sources has been used
to develop general capital, operating and overall costs for each
treatment and control method. Costs have been put on a
consistent industrial calculation basis of ten year straight line
depreciation, plus allowance for interest at six percent per year
(pollution abatement tax free money) and inclusion of allowance
for insurance and taxes for an overall fixed cost amortization of
fifteen percent per year. This generalized cost data, plus the
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Chemicals, U.S. Bureau of Census, Series M28A(71)-14.(1) These
values are summarized in Table 2. Also included are production
tonnages for years prior and subsequent to 1971, where available,
and the number of plants producing each chemical.
Aluminum Chloride
The anhydrous product is produced by the reaction of gaseous
chlorine with molten aluminum metal (scrap or scrap-pig mixture).
The basic equation is:
2A1 + 3C12 2A1C13
Chlorine is introduced below the surface of the molten aluminum.
The product sublimes and is collected by condensation. There are
three types of products manufactured, all from the same general
process:
(1) Yellow - this product is made using a slight excess of
chloride (0.0005 percent) and may contain some iron due
to reaction of the chloride with the vessel;
(2) White - this product has a stoichoimetric aluminum and
chlorine starting ratio; and
(3) Grey - this product contains 0.01 percent excess
aluminum. The unreacted aluminum raw waste lead is
higher for this grey material.
In most cases it makes little difference which of the above
grades is employed. In some pigment and dye intermediate
applications, the yellow material is preferred because it is free
of elemental aluminum.
Aluminum chloride is also made from the reaction of bauxite, coke
and chlorine. About 80 percent of all aluminum chloride made is
anhydrous. A solution grade of aluminum chloride is also
produced by reacting hydrated aluminum or bauxite ore with
hydrochloric acid. A standard process diagram is shown in Figure
1.
Annual U.S. production in 1971 totalled 26,399 kkg (29,100 tons).
The major use is as a catalyst in the petrochemical and synthetic
polymer industries,
The 1971 production for the 28 percent solution product was 7,650
kkg (8,400 tons).
Aluminum Sulfate
Aluminum sulfate is produced by the reaction of bauxite ore, or
other aluminum-containing compounds, with concentrated sulfuric
acid (60°Be). The general equation of the reaction is:
A1203 • 2H20 + 3H2S04-* A12 (S04) 3 + 5H20
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Hydrofluoric Acid Sodium Silicate
Calcium Oxide and Calcium Sodium Sulfate
Hydroxide
Nitric Acid Sodium Sulfite
Potassium Chromates Sulfuric Acid
Potassium Hydroxide Titanium Dioxide
Potassium Metal
The effluent limitation guidelines for existing point sources and
standards of performance for new facilities were developed in the
following manner. The point source category was first
categorized for the purpose of determining whether separate
limitations and standards are appropriate for different segments
within a point source category. Such subcategorization was based
upon raw material used, product produced, manufacturing process
employed, and other factors. The raw waste characteristics for
each sufccategory were then identified. This included an analysis
of (1) the source and volume of water used in the process
employed and the sources of waste and waste waters in the plant;
and (2) the constituents of all waste waters which result in
degradation of the receiving water. The constituents of waste
waters which should be subject to effluent limitations guidelines
and standards of performance were identified.
The full range of control and treatment technologies existing
within each subcategory was identified. This included an
identification of each control and treatment technology,
including both inplant and end-of-process technologies, which are
existent or capable of being designed for each subcategory. it
also included an identification of the quantity of constituents
(including thermal) and the characteristics of pollutants
resulting from the application of each of the treatment and
control technologies. The problems, limitations and reliability
of each treatment and control technology were also identified.
In addition, the non-water quality environmental impact, such as
the effects of the application of such technologies upcn other
pollution problems, including air, solid waste, noise and
radiation were also identified. The energy requirements of each
of the control and treatment technologies were identified as well
as the cost of the application of such technologies.
Cost information contained in this report was obtained directly
from industry during exemplary plant visits, from engineering
firms and equipment suppliers, and from the literature. The
information obtained from the latter three sources has been used
to develop general capital, operating and overall costs for each
treatment and control method. Costs have been put on a
consistent industrial calculation basis of ten year straight line
depreciation, plus allowance for interest at six percent per year
(pollution abatement tax free money) and inclusion of allowance
for insurance and taxes for an overall fixed cost amortization of
fifteen percent per year. This generalized cost data, plus the
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specific information obtained from plant visits, was then used
for cost effectiveness estimates in Section VIII and wherever
else costs are mentioned in this Document.
The data for identification and analyses were derived from a
number of sources. These sources included EPA research infor-
mation, published literature, qualified technical consultation,
on-site visits and interviews at numerous inorganic chemical
plants throughout the U.S., interviews and meetings with various
trade associations, and interviews and meetings with various
regional offices of the EPA. All references used in developing
the guidelines for effluent limitations and standards of
performance for new sources reported herein are included in
section XIII.
Exemplary plant selection
Eleven corporate headquarters were initially consulted for
assistance in preparing a list of potentially exemplary plants.
Eighty plants were studied in depth by consultations and review
of plant data. Of these, sixty plants were visited for
additional screening and data collection. Twenty-eight plants
were then visited and sampled by the contractor. This sampling
included all of the chemical processes subject to effluent
limitations guidelines. The following criteria were developed
and used for the selection of exemplary plants,
(a) Discharge effluent quantities
Plants discharging small quantities of pollutants or no process
waste water pollutants were preferred. This minimal discharge
may be due to reuse of water, raw material recovery and
recycling, or good water conservation. The significant parameter
was minimal waste added to effluent streams per weight of product
m anufactured.
(b) Water management practices
Use of good management practices such as water reuse, planning
,and in-plant water segregation, and the proximity of cooling
towers to operating units, where airborne contamination of water
can occur, were considered.
(c) Land utilization
The efficiency of land use was considered.
(d) Air pollution and solid waste control
Exemplary plants must possess overall effective air and solid
waste pollution control in addition to water pollution control
technology. Care was taken to insure that all plants chosen have
-------
minimal discharges into the environment and that exemplary sites
are not those which are exchanging one form of pollution for
another of the same or greater magnitude.
(e) Effluent treatment methods and their effectiveness
Plants selected generally have in use the best currently
available treatment methods, operating controls, and operational
reliability. Treatment methods considered included basic process
modifications which significantly reduce effluent loads as well
as conventional end-of-pipe treatment methods.
(f) Plant facilities
All plants chosen as exemplary had all the facilities normally
associated with the production of the specific chemical (s) in
question. These facilities, generally, were plants which have
all their normal process steps carried out on-site.
(g) Plant management philosophy
Plants were preferred whose management insists upon effective
equipment maintenance and good housekeeping practices. These
qualities are best identified by a high operational factor and
plant cleanliness.
(h) Diversity of processes
On the basis that all of the above criteria are met, consider-
ation was given to installations having a multiplicity of man-
ufacturing processes. However, for sampling purposes, the
complex facilities chosen were those for which the wastes could
be clearly traced through the various treatment steps.
(i) Product purity
For cases in which purity requirements play a major role in
determining the amounts of wastes to be treated and the degree of
water recycling possi bl e, di fferent product grade s were
considered for sub-categorization.
Sampling of Exemplary Plants
The details of how the exemplary plants were sampled and the
analytical techniques employed are fully discussed in Section V.
GENERAL DESCRIPTION OF THE INDUSTRY
Brief descriptions of each of the twenty-two chemical
sufccategories are presented below. Process flow sheets for the
various subcategories are included. Production tonnages reported
for 1971 were taken from Current Industrial Reports, Inorganic
-------
Chemicals, U.S. Bureau of Census, Series M28A(71)-1U.(1) These
values are summarized in Table 2. Also included are production
tonnages for years prior and subsequent to 1971, where available,
and the number of plants producing each chemical.
Aluminum Chloride
The anhydrous product is produced by the reaction of gaseous
chlorine with molten aluminum metal (scrap or scrap-pig mixture).
The basic equation is:
2A1 + 3C12 2A1C13
Chlorine is introduced below the surface of the molten aluminum.
The product sublimes and is collected by condensation. There,are
three types of products manufactured, all from the same general
process:
(1) Yellow - this product is made using a slight excess of
chloride (0.0005 percent) and may contain some iron due
to reaction of the chloride with the vessel;
(2) White - this product has a stoichoimetric aluminum and
chlorine starting ratio; and
(3) Grey - this product contains 0.01 percent excess
aluminum. The unreacted aluminum raw waste lead is
higher for this grey material.
In most cases it makes little difference which of the above
grades is employed. In some pigment and dye intermediate
applications, the yellow material is preferred because it is free
of elemental aluminum.
Aluminum chloride is also made from the reaction of bauxite, coke
and chlorine. About 80 percent of all aluminum chloride made is
anhydrous. A solution grade of aluminum chloride is also
produced by reacting hydrated aluminum or bauxite ore with
hydrochloric acid. A standard process diagram is shown in Figure
1.
Annual U.S. production in 1971 totalled 26,399 kkg (29,100 tons).
The major use is as a catalyst in the petrochemical and synthetic
polymer industries.
The 1971 production for the 28 percent solution product was 7,650
kkg (8,UOO tons).
Aluminum Sulfate
Aluminum sulfate is produced by the reaction of bauxite ore, or
other aluminum-containing compounds, with concentrated sulfuric
acid (60°Be). The general equation of the reaction is:
A1203 • 2H20 + 3H2S04-* A12(SOU) 3 + 5H20
-------
TABLE 2. .U.S. Production of Inorganic Chemicals (Metric Tons)
1973 (Est.)
A1CU
A1£(S04)3.
CaC£.
CaCl.2.
Cl 2(g)
HC1
HF
H2J32
Linfe
H'woa
K2Cr207
KOH
K
K2S0.4,
N a H C 0.3.
9,480,031
2,131,873
6,731,276
V
8
1
6
1972
30
,019
447
86^
,952
,996
301
68
,369
(Estimated)4
91
Na£C03., total
Synthetic
NaCl
NaCl (Solar)
NaCl (Solutl
Na2Cr207 (&
NaQH
Na
3,991 ,592
on Mining)
Chromate)
9,797,544
6
3
9
Sodium Sil icate
N alSO 4
N a2.S 03
H2.S04.
TiO^.
29,664,786
644,098
1
,27
161
,768
,929
124
,196
601
,236
,257
623
,844
,670
,240
^821
,052
,703
,184
,039
,311
,309
,478
,470
,904
,284
,084
,460
,486
,130
,233
1971
26
1,084
566
1,100
8,483
1 ,904
199
58
6,116
179
407
158
6,396
3,878
2,350
5,928
125
9,276
138
569
1,230
185
26,691
615
,399
,080
,988
,409
,947
,171
,126
,060
,208
,622
59
,959
,756
,526
,194
,000
,000
,191
,006
,799
,709
,136
,065
,000
,068
1970
28
1,080
717
1 ,006
8,857
1,827
203
55
6,059
158
296
129
3,985
139
9,199
155
569
1,245
222
26,784
594
,485
,451
,579
,000
,700
,060
,571
,3.38
,055
,756
285
,285
,727
,242
,706
,712
,128
,709
,558
,259
,489
,203
No. of
Plants
1969 (1971)
35
1,136
776
1,066
7,801
1,733
200
58
15,422
5,844
160
277
124
6,350
4,118
39,008
138
8,996
149
596
1,341
205
26,795
602
,834
,696
,546
,843
,748
,621
,940
,967
,060
,960
,570
,143
,284
,260
,597
,740
,798
,504
,685
,017
,719
,930
,375
,367
5
100
7
9
63
83
13
5
97
72
2
13
1
7
5
13
7
85
6
?
6
62
5
33
40
6
150
14
11
-------
(NaOH)
WATER VENT
PHI flRINF . ">»
RFAPTOR
v
WASTE
(DROSS, SOLID)
\
-^ rnNnFM^FR WASTE ^
> CONDENSER GASES )
(CI2 +
PARTICULATE
AICI3)
V
AICI3
PRODUCT
/\
/
CrpllDRPR
V
WttSTE
AI(OH)3
(NaCt)
(NaOCI)
HCl
FIGURE 1
STANDARD
ALUMINUM CHLORIDE FLOW DIAGRAM
-------
Ground ore and acid are reacted in a digester, from which the
products, aluminum sulfate in solution plus muds and other
insoluble materials from the ore, are fed into a settling tank.
The aluminum sulfate solution is then clarified and filtered to
remove any remaining insolubles. It may be sold as solution or
evaporated to yield a solid product. A typical process diagram
is shown in Figure 2.
Annual U.S. production in 1971 was 1,084,080 kkg (1,195,000
tens). Aluminum sulfate, or filter alum, is used for , water
treatment (flocculation and clarification) and in treatment of
paper mill waste, sewage, and other waste streams.
Calcium Carbide
This chemical is prepared by the reaction of calcium oxide with
carbon (in the form of coke, petroleum coke, or anthracite) at
2000-2200°C (3632-3992°F) in a furnace similar to the familiar
arc furnace, as shown in Figure 3. The general equation for the
reaction is:
2CaO + 4C -f Heat
2CaC2
02
Calcium carbide is used primarily in the manufacturing of
acetylene (by reaction with water). This use and the tonnage
production has been steadily decreasing. Still, many calcium
carbide plants are located in conjunction with acetylene plants.
Since the production process is dry, the only major discharges
are those effluents from scrubbing furnace and kiln offgases.
The U.S. production in 1971 was 567,182 kkg (625,338 tons).
Calcium Chloride
Most of the calcium chloride produced is extracted from impure
natural brines, but some of this salt is recovered as a by-
product of soda ash manufacture by the Solvay process. In the
manufacturing of calcium chloride from brine, the salts are
solution mined and the resulting brines are first concentrated to
reirove sodium chloride by precipitation and then purified by the
addition of other materials to precipitate sodium, potassium, and
magnesium salts. The purified calcium chloride brine is then
evaporated to yield a wet solid which is flaked and calcined to a
dry solid product. Extensive recycling of partially purified
brine is used to recover most of the sodium chloride values. A
standard process diagram is shown in Figure 4.
Manufacture of calcium chloride frcm Solvay process waste liquors
is similar to the natural brine process, except that the stepwise
concentration and purification is unnecessary because no
magnesium is present. Evaporation and calcining procedures are
similar to those above. Significant wastes result from calcium
chloride manufacturing.
13
-------
SULFURIC BAUXITE
ACID ORE
WASHOUT <
WASTES
(MUDS, AUSOJ,,
H2S04)
WASTE
(MUDS)
DIGESTER
V
SETTLING
TANK
WASTE
(MUDS)
V
FILTRATION
STORAGE
LIQUID
ALUMINUM
SULFATE
PRODUCT
EVAPORATION
SOLID
ALUMINUM
SULFATE
PRODUCT
STEAM
FIGURE a
STANDARD PROCESS DIAGRAM FOR
ALUMINUM SULFATE MANUFACTURE
-------
COKE
COAL
LIMESTONE-
CRUSHING
I HOT AIR
AIR-SWEPT
PULVERIZING
DRYING
CRUSHING
KILN
WATER SPRAY
COOLER
AIR
GAS VENT
T»
GAS
SCRUBBER
CARBIDE
FURNACE
COOLING
w
CRUSHING
FIGURE 3
STANDARD
CALCIUM CARBIDE FLOW DIAGRAM
\f
STORAGE
V
WASTE
-------
SOLVAY WASTE LIQUOR.
OR PURIFIED BRINE '
MULTIPLE
EFFECT
EVAPORATOR
SODIUM
CHLORIDE
FINISHING
PAN
CALCIUM CALCIUM
CHLORIDE CHLORIDE
(SOLUTION) (SOLID)
FLAKER
FURNACE
CALCIUM
CHLORDE
(ANHYDROUS)
V
CALCIUM
CHLORIDE
(FLAKES)
FIGURE 4.
STANDARD PROCESS FOR CALCIUM CHLORIDE MANUFACTURE
-------
In 1971, U.S. production of calcium chloride was 1,101,281 kkg
(1,213,000 tons). Uses include de-icing of roads, use as a
stabilizer in pavement and cement, and dust control on roads.
Production is increasing as more uses and markets are found, but
potential production capability is much greater than that
presently utilized. Recently, increased recovery resulting from
pollution abatement measures has tended to cause calcium chloride
supply to exceed demand. Plants recovering this salt from
natural brines are located near mixed salt deposits, such as
those in Michigan, West Virginia, and California.
Calcium Oxide and Calcium Hydroxide
Calcium oxide is produced by calcining various types of limestone
in a continuous vertical or rotary kiln. The general equation
for the reaction is:
CaCO3 + Heat-*-CaO + C02
Formerly coal or coke was used as fuel in vertical kilns, but in
recent years large gas-fired kilns have been widely used. After
calcination, the calcium oxide is cooled and then packaged or
crushed and screened to yield a pulverized product. It may be
slaked by reaction with water to yield calcium hydroxide and then
marketed. The only waterborne wastes result from wet scrubbing
of the gaseous kiln effluent to remove particulates. These
wastes are high pH liquors which also contain suspended solids.
The standard process diagram is shown in Figure 5.
Annual U.S. production of lime is believed to total about
16,000,000 kkg (17r600,000 tons). Approximately 20 percent of
this production is "captive" (made and consumed in the same
facility), primarily in the sugar, alkali, and steel industries.
The remainder finds a variety of chemical and industrial uses,
including use as an alkali and use in hydrated lime
manufacturing. Principal growth areas appear to be in basic
oxygen steel production and in soil stabilization.
Chlorine, Sodium or Potassium Hydroxide
The major chlorine production results from the electrolysis of
sodium or potassium chloride brines, in which caustic soda (NaOH)
or caustic potash (KOH), respectively, are also produced. The
general equation for the electrolysis is (where M can be either
Na or K):
dc
3 MCI + 2H2O-*C12 + 2MOH + H2
From the above equation it can be seen that hydrogen is also a
by-product of brine electrolysis.
17
-------
LIMESTONES
COKE
MIXING
WEIGHT
CO
(DRY SCRUBBER...WASTE
C02 TO < PRECIPITATOR WASTE
I COLLECTION OR USE
CALCINING
COOLING
UNBURNED LIME
WATER VENT
V
LIME
PRODUCT
1
SLAKING
SCREENING
_V
MILK OF LIME
Ca(OH)2
PRODUCT
FIGURE 5
STANDARD
CALCIUM OXIDE (LIME) FLOW DIAGRAM
-------
Other sources (minor in size) of chlorine include the manufacture
of hydrochloric acid and metallic sodium,
Two types of electrolysis cells are used, mercury cells and
diaphragm cells.
a) Diaphragm cell process
In the diaphragm cell process. Figure 6, sodium chloride trines
are first purified by addition of sodium carbonate, lime
flocculating agents and barium carbonate in the amounts required
to precipitate all the magnesium, calcium and sulfate contents of
the brine. The brine is filtered to remove the precipitated
materials and is then electrolyzed in a diaphragm cell.
Chlorine, formed at one electrode, is collected, cooled, dried
with sulfuric acid, then purified, compressed, liquified and
shipped. At the other electrode, sodium hydroxide is formed and
hydrogen is liberated. The hydrogen is cooled, purified,
compressed and sold and the sodium hydroxide formed, along with
unreacted brine, is then evaporated at 50 percent concentration.
During partial evaporation, most of the unreacted sodium chloride
precipitates from the solution, which is then filtered. The
collected sodium chloride is recycled to the process and the
sodium hydroxide solutions are sold or further evaporated to
yield solid products.
In cases where potassium hydroxide is manufactured as a co-
product with chlorine, purified potassium chloride is used
instead of sodium chloride as the starting material. Otherwise,
the process is identical.
b) Mercury cell process
Figure 7 shows a standard process diagram for sodium hydroxide
and chlorine production by the mercury cell process. The raw
material salt, is dissolved and purified by addition of barium
chloride, soda ash, and lime to remove magnesium and calcium
salts and sulfates prior to electrolysis. The insolubles formed
on addition of the treatment chemicals are filtered from the
brine and the brine is fed to the mercury cell, wherein chlorine
is liberated at one electrode and a sodium-mercury amalgam is
formed at the other.
Mercury cells utilize mercury flowing along the bottom of a steel
trough as the cathode, A multiple anode is comprised of
horizontal graphite plates. Upon electrolysis the alkali metal
forms an amalgam with the mercury. The amalgam is decomposed
externally to the cell by the addition of water, which results in
the formation of hydrogen.
The chlorine gas from the cells is collected, cooled, dried by
contact with sulfuric acid, and then purified and liquified for
-------
ro
o
SOLUTION
MINING
ROCK
AND
DISSOLVE
WASTE
SOLAR
AND
DISSOLVE
Nd
u
*
to -
Cl 03
NaOH
SALE
NaOH
CENTRATION
TO PROCEI
Cl?
PRELIMINARY
2 ^ PURIFICATION ^ L
•* AND c. ^
COMPRESSION l£
V \/
WASTE
CHLORINATED _„„
YDROCARBONS) pSpinc/
VENT
A
SCRUBBER
ss '** 1
WASTE
~ " ,WAIER,
(NaOCI)
.IQUIFACTION x
(OPTION) ~P
CI2
HIGH
ARY ^PUR
ITION ^CI2
SAL
SOLID X = PROPRIETARY INGREDIE
-> NaOH (POLYELECTROLYTES,
SALE FLOCCULANTS, ETC. )
LOW
PURITY
Cle
SALE
FIGURE 6
STANDARD
CHLORINE-CAUSTIC SODA FLOW DIAGRAM - DIAPHRAGM CELL PROCESS
-------
£T
O
10 u
0 O IJ
WO ~
o W I
Til
w \b \|/ ^
•o CONDENSATE H9
3 A
* \
S
cn, Irmw ..„„, BRINE • M ^ H2 COOL
SOLUTION NoCI >. PURIFICATION .N EVAPORATION o ^ *> AND
MINING ^ FILTRATION ^ % J- 5 ' TREAT
O X D
z o m
^
WASTE
_„. , >
•^
ROCK NoC|
DISSOLVE '
s
I
WASTE
SOLAR Wnr,
AND NaCI
DISSOLVE
WASTE
X = PROPRIETARY INGREDIENTS
(POLY ELECTROLYTES,
FLOCCULANTS, ETC.)
SALT a V S*
^, WAS It -ji'11
' ^' ^' ^L , w , , f
Hg CELL 3?
SATURATION ; i-> ELECTROL. ICIo- COOLING
WTELJ DENUDER &
I
V SPENT SALT 50% WASTE
WASTE j NOOH T0 PROCESS
V _ . , V 4
(PURSE)
PURIFICATION CI2 TO
S/ COMPRESSION "^L.QU.FICAT.ON
CAUSTIC »L
FILTRATION WASTE
— >NoOH
WASTE
FIGURE r
STANDARD
CHLORINE-CAUSTIC FLOW DIAGRAM MERCURY CELL PROCESS
-------
shipment, utilized on-site, or sold as gaseous chlorine. Much of
the unreacted salt in the brine is recycled. Besides potential
caustic and brine effluents some mercury is present in the spent
brine from the mercury cell process. The gost of removing
mercury from the effluent accounts, to some extent, for the shift
back toward the diaphragm cells. Mercury cells began to be
widely used in the early 1950's and reached a high of almost 30
percent of the total production in 1963.
The U.S. production of chlorine in 1971 totalled 8,482,660 kkg of
gas (9,352,437 tons) and 4,035,489 kkg of liquid (4,449,271
tons). At present, about 75 percent of the production is in
diaphragm cells, 20 percent in mercury cells, and 5 percent from
other sources. About two-thirds of the production is utilized in
the synthetic organic chemical and plastics industries, and half
of that remaining is utilized in the pulp and paper industry (as
a bleaching agent). Other uses include the inorganic chemicals
industry, municipal water and sewage treatment, and many others.
Somewhat over half of the total production is "captive",
primarily in the synthetic organic chemicals and the Fulp an<3
paper industries. In recent years proximity to markets has been
the major factor in chlorine plant location, in contrast to the
cost of power and salt which previously dominated plant
economics.
Sodium hydroxide is produced from the electrolysis of sodium
chloride brines in mercury or diaphragm cells as described above.
The caustic solution from the cathode of the electrolysis cell is
evaporated to about 50 percent by weight sodium hydroxide. This
may be sold as "standard-grade caustic liquor", concentrated to
73 percent, or further refined through removal of chloride and
chlorate by various techniques. Refined caustic liquor may be
sold, further concentrated to 73 percent solids, or evaporated to
dryness. The anhydrous sodium hydroxide is sold in solid (flake
or powdered) forms. Most of the product is sold in the liquid
form.
Caustic soda has many varied uses, mostly as an alkali. It has
also replaced soda ash (sodium carbonate) in many uses, such as
in the aluminum industry and in other molten salt processes. It
is used to manufacture soda ash in one plant. In 1971, the U.S.
production of sodium hydroxide was 8,780,946 kkg (9,681,397 tons)
in liquid form and 493,393 kkg (543,983 tons) in solid form.
Production methods for potassium hydroxide are very similar to
those for sodium hydroxide, except that mined potassium chloride
brines are used as the raw material. In the mercury cell
process, the potassium-mercury amalgam is decomposed with water.
The mercury is recycled and the caustic solution is cooled and
filtered to recover potassium hydroxide.
-------
The U.S. production of potassium hydroxide in 1971 was 179,760
kkg (198,192 tons). Caustic potash is used as an alkali,
particularly when very high purity is desired or where other
factors allow it to compete with sodium hydroxide (captive
production, for instance). Other uses include the manufacturing
xbf potassium salts and organic compounds containing potassium.
Hydrochloric Acid
There are two major processes used for hydrochloric acid
manufacture. The process considered in this Document, as shown
in Figure 8, is direct reaction of chlorine with hydrogen by:
C12 + H2-V2HC1
The second major source of production for hydrochloric acid, as a
by-product of organic chlorination reactions, is the dominant
source. This process is beyond the scope of this Document. By-
product hydrochloric acid is typically of lower purity than that
produced by direct reaction.
In the production of hydrochloric acid by direct reaction,
hydrogen and chlorine gases are reacted in a vertical burner.
The product hydrogen chloride so formed is cooled and then
absorbed in water. Exhaust gases are scrubbed, and acid values
are recycled. End products may include strong acid (22°Be) from
the cooler, weak acid (18°Be) from the absorber column, a mixture
of these (20°Be), or anhydrous HC1. . The anhydrous acid may be
prepared by stripping gaseous HCl from strong acid. The
condensate and column bottoms from this process may then be
recycled back into the hydrochloric acid recovery process.
Approximately 90 percent of the current production is byproduct,
and supply often exceeds demand. Uses include pickling of steel,
chlorination reactions (in place of chlorine), and a variety of
uses as an acid agent. Total U.S. production in 1971 was
1,904,075 kkg (2,099,371 tons) .
Hydrofluoric Acid
Hydrofluoric acid is obtained by reacting the mineral fluorspar
(CaF2) with concentrated sulfuric acid in a furnace, as shown in
Figure 9. The general reaction for this process is:
CaF2 + H2S04 > Heat -»- H2F2 + CaS04
The hydrofluoric acid leaves the furnace as a gas, which is then
cooled and absorbed in water prior to purification. In the
purification system, the crude acid is redistilled and either
absorbed in water to yield aqueous hydrofluoric acid or
compressed and bottled for sale as anhydrous hydrofluoric acid.
Final drying of the anhydrous gas is accomplished with
23
-------
PROCESS
WATER
V
HYDROfiFN. - -. ^
DUHNtK ? UUULtn
CHI ORINF .:•*
A
v vy
COOLING 22° Be
WATER ACID
PROCESS
WATER
vl
w
VE
/
N'
SCRUBBER
NT
^
T ^J^
(8° Be LJRECYCLED AT &
ACID EXEMPLARY PLANT)
FIGURE <5
STANDARD
HYDROCHLORIC ACID FLOW DIAGRAM (SYNTHETIC PROCESS)
-------
OLEUM
V
V
MIXER
r
CALCIUM
FLUORIDE^
REACTOR
~i
k^-
WASTE
HF
COOLER
I I
WATER
DRIP POT
V
COKE BOX
CRUDE HF STORAGE
V
H^S04 SCRUBBER
DISTILLER
BOTTOM ACID
STORAGE
\ f
~I
TAILS TOWER
V
WASTE
STRIPPER
WATER
EJECTOR
WASTE HF
PRODUCT
WASTE
ACID ABORBERS
WATER
1, ,
(
EJECTOR
- — >TO ACID STORAGE
WASTE
FIGURE 9
HYDROFLUORIC ACID FLOW DIAGRAM
-------
concentrated sulfuric acid. Aqueous acid is normally shipped as
70 percent acid.
Most U.S. hydrofluoric acid production (probably 75-80 percent)
is captive to the fluorinated organics and plastics industries.
Total U.S. production in 1971 was 199,069 kkg (219,481 tons), and
the production appears to be increasing fairly rapidly.
Fluorinated organics and plastics comprise the major use
industries. Another major use is in the production of synthetic
cryolite and aluminum fluoride. Most of the acid-grade fluorspar
ore is imported. Waste disposal problems and safety hazards are
specialized and severe because of the reactivity of the material.
Hydrogen Peroxide
Hydrogen peroxide is manufactured by three different processes:
(1) An electrolytic process; (2) Oxidation of alkyl
hydroanthraquinones; and (3) As a by-product in the manufacturing
cf acetone from isopropyl alcohol. This Document includes
processes (1) and (2).
a) Electrolytic process
In the electrolytic process, a solution of ammonium (or other)
bisulfate is electrolyzed, yielding ammonium persulfate at the
ancde and hydrogen gas at the cathode. The persulfate is then
reacted with water (hydrolyzed) to yield hydrogen peroxide and
the original bisulfate. The general reaction scheme is:
dc
2NH4HSO** —*• (NHU) 2S208 * H2
(NH4)2S208 + H20—V2NH4HS04 + H202
The crude peroxide product emerges mixed with water, and can be
concentrated to desired levels by vacuum distillation or low-
temperature fractionation. The cathode liquor is filtered and
reused. A standard flow diagram is shown in Figure 10.
b) Organic process
The alkylhydroanthraquinone oxidation process is shown in general
form below ("R" represents the alkylanthraquinone molecule,
except for the two double-bonded oxygens):
Cat.
O=R=O + H2—> HO-R-OH
HO-R-OH + O2—»-0=R=0 + H202
In this process, the alkylanthraquinone is reduced by hydrogen
over a supported metal catalyst (typically palladium on alumina),
the product being the corresponding alkylhydroanthraquinone.
This, in turn, is oxidized by oxygen in a forced gas stream to
26
-------
COOLING WATER
AMMONIUM
SULFATE
SERIES OF
ELECTROLYTIC
CELLS
/•
I
u
/\ 1
y WATER
NODE LIQUOR WATER I
EVAPO
1
CATHODE LIQUOR
\l/
FILTER
^
,
^
COOLER
COOLER
UA-mR _^ FRACTIONATING . ^ rnn, FB _\ rvAPrtPAirw • > PACKED s FUAPO
WATER
RATOR > PACKED
RATOR -^ TQWER
HYDROGEN WASTE HYDROGEN WASTE HYDROGEN
PEROXIDE PEROXIDE PEROXIDE
( 30%) (65°/J ( 80-85%)
WASTE
FIGURE 10
STANDARD HYDROGEN PEROXIDE ELETROLYTIC PROCESS FLOW DIAGRAM
-------
reform the original alkylanthraquinone plus hydrogen peroxide.
The hydrogen peroxide is extracted with water and the
alkylanthraquinone is recycled. The recovered product is then
concentrated, purified, and sold. A general process diagram for
the organic process is shown in Figure 11.
Hydrogen peroxide is sold in a range of aqueous concentrations
from three percent to 98 percent by weight. The higher con-
centration materials are dangerously reactive. A stabilizer
(such as acetanilid) is typically added to the product to retard
decomposition. Uses include bleaching of textiles and paper,
epoxidation, production of peroxy-acid catalysts, oxidation of
organic compounds, formation of foams, and a source of energy for
both military and civilian applications. The U.S. production in
1971 was 57,937 kkg (63,878 tons).
Nitric Acid
This document covers production of nitric acid in concentrations
up to 68 percent by weight (azectropic concentration). More
concentrated nitric acid, including fuming nitric acid and
nitrogen pentoxide will be included in the Phase II Document.
The production of nitric acid by the reaction of sodium nitrate
and sulfuric acid is also not included.
Nitric acid is produced by the catalytic oxidation of ammonia,
first to nitric oxide (NO), and then to nitrogen dioxide (NO2) ,
which is reacted with water under pressure to form the acid as
shewn in Figure 12. The overall reaction scheme is:
cat.
UNH3 + 5O2 —*• UNO + 6H20
2NO + 02 —>- 2N02
3NO2 + H20 —»- 2HN03 + NO
In the process, compressed, purified, and preheated air and
anhydrous ammonia are mixed and passed over a platinum rhodium
wire-gauze catalyst at about 750°C (1382°F). The resultant
mixture of nitric oxide and excess air is introduced, along with
additional air, into a stainless steel absorption tower in which
the nitric oxide is further oxidized. The resulting nitrogen
dioxide is reacted with water. The bottm of the tower yields 61
- 65 percent by weight nitric acid.
Most of the U.S. nitric acid production is utilized in the
fertilizer industry. The second largest use is in explosives
manufacturing. Various uses as an acidic or pickling agent
account for much of the remaining production. Total U.S.
production in 1971 was 6,151,112 kkg (6,742,130 tons).
-------
RANEY
NICKEL
CATALYST HYDROGEN
i
9
u.
C9
M
o:
o
5
*•*-
IVERTED THUS
Q
Ld
CD
§
:
:D
u.
i
1
UJ
X
I'-
ll.
i
i
1
2
-
1
YDROGENATOR FILTER
>
'
FILTER
A N
COOLING
WATER
' V
COOLER
UULJUULJU
N
f
OXIDIZING
VESSEL
WATER
Mf \
f
EXTRACTS
TOWER
N
DRYING
>
<— OXYGEN
20-25% H202
A !
RECYCLE ^
f 15% C
TOWER
f
CLAY BED
>
\
f
NICKEL-SILVER
CATALYST BED
>F PRODUCT 50"/o H?°2
\t
Ha°2
PURGE
WASTE
FIGURE 11
STANDARD
HYDROGEN PEROXIDE FLOW DIAGRAM
(RIEDL-PFLEIDERER PROCESS)
-------
CO
o
AMMONIA
(ANHYDROUS)
EVAPORATOR
AIR
COMPRESSOR
REACTOR
A
FILTER
WASTE
WATER GASES
/N
COOLER
WEAK ACID
AIR
ABSORBER
V
NITRIC ACID
(61-65%)
FIGURE 12
STANDARD NITRIC ACID PROCESS FLOW DIAGRAM
-------
Potassium Metal
Potassium is produced by the reaction of potassium chloride with
sodium vapor:
KC1 + Na + Heat —> K + NaCl
For the commercial preparation of potassium metal, potassium
chloride is melted in a gas fired melt pot and fed to an exchange
column as shown in Figure 13. The molten potassium chloride
flews over Raschig rings in the packed column, where it contacts
ascending sodium vapors coming from a gas-fired reboiler. An
equilibrium is established between the two, yielding sodium
chloride and elemental potassium. The sodium chloride formed is
continuously withdrawn at the base of the apparatus and is
normally sold. The column operating conditions may be varied to
yield either pure potassium metal as an overhead product or tc
vaporize sodium along with the potassium to produce sodium-
potassium (NaK) alloys of varying compositions, potassium metal
of over 99.5 percent purity can be continuously produced.
Since it is relatively more reactive than sodium, the reaction
between potassium and carbon (plus a tendency to form explosive
carbonyls) precludes the manufacture of potassium by
electrolysis. Because it is more expensive than sodium,
potassium has very limited uses. Major uses include manufacture
of organo-potassium compounds and production of NaK (sodium
potassium alloys used in lard modification and as a nuclear
reactor coolant). Total U.S. production in 1972 was about 10.0
kkg (110 tons), primarily from one facility.
Potassium Dichromate
Mcst of the potassium dichromate manufactured in the U.S. is
made by reacting a sodium dichromate dihydrate solution with
potassium chloride according to the following:
Na2Cr207«2H20 + 2KCl-*-K2Cr207 + 2NaCl + 2H20
Potassium chloride is added to a dichromate solution, which is
then pH adjusted, saturated, filtered and vacuum cooled to
precipitate crystalline potassium dichromate which is recovered
by centrifuging, dried, sized and packaged. The mother liquor
from the product centrifuge is then concentrated to precipitate
sodium chloride which is removed as a solid waste from a salt
centrifuge. The process liquid is recycled to the initial
reaction tank. Figure 14 is the standard process diagram. A
relatively pure product results which requires only removal of
the water prior to sizing and packaging.
The major uses of potassium dichromate are as a glass pigment and
a photographic development chemical. Estimated annual production
in the U.S. is 4,000-4,500 kkg (4,400-5,000 tons).
31
-------
TRAP
K (OR NaK) VAPOR
COLUMN
MOLTEN KCI
NaCI (SOLD)
Na VAPOR,
STAINLESS
STEEL
RASCHI6
RINGS
RECEIVER
HEAT
«•
<
V
CONDENSATION
K
(OR
NaK ALLOY)
•HEAT
FIGURE 13
COMMERCIAL EXTRACTION OF POTASSIUM
32
-------
U)
RECYCLED LIQUOR
SODIUM
DICHROMATE
LIQUOR
KCI
FROM in; TO
RIVER, ny .RIVER
MOTHER
LIQUOR
SALT
CONCENTRATOR
(STEAM
HEATED)
SALT
CENTRIFUGE
SODIUM
CHLORIDE
SOLID
W4STE
FIGURE 14.
STANDARD POTASSIUM DICHROMATE PROCESS FU3W DIAGRAM
-------
Potassium Sulfate
The bulk of the potassium sulfate manufactured in the U.S. is
prepared by the treatment with potassium chloride of dissolved
langbeinite, a naturally-occuring potassium sulfate-magnesium
sulfate mineral, K2SO^«2MgSCKU Mined langbeinite is crushed and
dissolved in water to which potassium chloride is added. Partial
evaporation of the solution results in selective precipitation of
potassium sulfate which is recovered by centrifugation or
filtration, dried, and sold. The remaining brine liquor is
either discharged to an evaporation pond, reused as process
water, or evaporated. Magnesium chloride may te economically
recovered as a byproduct if the raw material is of sufficiently
high quality. A standard process diagram is shown in Figure 15.
Current annual production in the U.S. is 407,916 kkg (449,742
tons), Much of this finds agricultural use, particularly for
totacco and citrus.
Scdium Bicarbonate
Sodium bicarbonate, also known as baking soda, is made by the
reaction of sodium carbonate with water and carbon dioxide under
pressure, as shown in Figure 16. The bicarbonate so formed
precipitates from the solution and is filtered, washed, dried,
and packaged. The general process reaction is:
Na2_C03 + H20 + C02-*-2NaHC03
Sodium bicarbonate is typically a minor by-product of soda ash
manufacturers.
Total U.S. production in 1971 was 158,305 kkg (174,537 tons).
Major industrial users include food processors, chemical plants,
pharmaceutical producers, synthetic rubber manufacturers, leather
processors and paper and textile producers. It is also used in
fire extinguishers to form carbon dioxide and in food
preparation.
Sodium Carbonate
Scdium carbonate, or soda ash, is produced by the "Solvay"
process and by mining naturally-occuring deposits in California
and Wyoming, Production by mining is less than that from the
Solvay process. In the mining process, trona (sodium
sesquicarbonate, Na2CO3_«NaHCO3_«2H20) is brought tc the surface in
solid form, crushed and ground, and dissolved in water. The
solution is clarified, thickened, filtered, and sent to vacuum
crystallizers, from which part of the soda ash is recovered in
solid form. The remaining solution is cooled to precipitate
additional soda ash and bicarbonate. These solids are then
dewatered and calcined to yield soda ash.
34
-------
MINING
CRUSHING
LEACHING
V
DEWATERING
DRYING
PRODUCT SIZING
STANDARD
GRANULAR
V
SUSPENSION
PROCESS K-MAG
K-MAG {KgS04-'
V
GRINDING
HYDRAT10N
MURIATE (KCI)
V
EVAPORATION
REACTION
V
h BRINE
WASTE
,K2S04
DRYING
REACTION SOLIDS
(HIGH GRADE K2S04)
GRANULATION
PRODUCT SIZING
STANDARD
GRANULAR
FERTILIZER GRADE SULFATE
FIGURE 15
STANDARD POTASSIUM SULFATE PROCESS DIAGRAM
35
-------
SODA ASH WATER
r
WASTE
CHARGING
MIXING
FEEDING
CARBONAT1NG
CENTRIFUGING
DRYING
COLLECTING
V
SCREENING
AND/OR
MILLING
PRODUCT
TO
STORAGE
PRODUCT
•TO
STORAGE
RGURE
STANDARD SODIUM BICARBONATE PROCESS
FLOW DIAGRAM
3b
-------
The splvay process, as shown in Figure 17 r involves a reaction in
aqueous solution (under pressure) between ammonia, brine (NaCl) ,
and carbon dioxide to yield sodium bicarbonate, which is then
converted to soda ash by heating. Ammonia is recovered by the
addition of slaked lime to the used liquor. The general reaction
is as follows:
Formation of Ammonium Bicarbonate
NH3 + H2O-^NH40H
NH40H + C02->-NH4HC0.3
Conversion to Sodium Bicarbonate
NH4HCQ3 + NaCl-*-NaHCQ3 + NH4C1
Conversion to Soda Ash
2NaHC03
C02 + H20
Recovery of Ammonia
2NH4C1 + Ca(OH) 2-^2NH3
CaCl2
H20
The saturated brine is purified of other metal ions by preci-
pitation, and then picks up ammonia in an absorber tower.
Ammoniated trine is reacted with carbon dioxide in a carbonating
tower, and the resulting bicarbonate precipitates as the sodium
salt, forming a slurry. The slurry is filtered to remove the
solid bicarbonate which is calcined to yield the light ash
prcduct. Dense ash is made by successive hydration and
dehydration of the light ash. The carbon dioxide and ammonia are
recycled. calcium chloride is also being recovered now in some
plants.
Many soda ash plants are associated with producers of glass
(largest user industry) or with sources or raw material such as
coke-oven plants (by-product ammonia) » the cement industry
(utilization of lime sludge) , or solid carbon dioxide producers.
Soda ash competes with caustic soda and other chemicals in a
variety of applications other than glass manufacture. Large
amounts are used in the non-ferrous metals industry and in the
production of bicarbonate and washing soda. several types of
products are sold commercially. Production figures for the U.S.
in 1971 are as follows:
Finished Light Ash
Finished Dense Ash
Natural Ash
Total
Sodium Chloride
1,676,621 kkg (Ir848,535 tons)
2,120,467 kkg (2,337,891 tons)
2,598,321 kkg (2,864,742 tons)
6,395,409 kkg (7,051,168 tons)
Large quantities of this chemical
seawater by three basic processes:
are produced from brine or
37
-------
STEAM + CO2
BRINE-
CO
CO
BRINE
PURIFICATION
1
WASTE
URIFICATION MUDS,
aC03,Mg(OH)2,ETC.)
V
REACTOR
/
C02
PRECIPITATOR
WATER
J,
LIME
KILN
/JW
LIMESTONE-1
^
RECYCL
.»«»,»
CALC
IMFR
SODA ASH
P STORAGE
SPENT BRINE
SLAKER
* NH4CI
-E NH3
^
/
NHg
STILL
1 X
1
1
1
T.
WASTE(CaCI2 AND NaCl)
r-J' OPTIONAL CaCI 2 RECOVERY
EVAPORATOR
— CaCI2-^ DRYING |
I
WAS1
\
TE CaCI2
^aClj CoClg) PRODUCT |
FIGURE 17
SOLVAY PROCESS SODIUM CARBONATE FLOW DIAGRAM
-------
(1) solar evaporation of brine;
(2) solution mining of natural salt; and
(3) conventional mining of rock salt.
a) Solar evaporation process
In the solar evaporation process, salt water is concentrated by
evaporation over a period of several years in open ponds to yield
a saturated brine solution. After saturation is reached, the
brine is then fed to a crystallizer, wherein sodium chloride
precipitates, leaving behind a concentrated brine solution
(bittern) consisting of sodium, potassium and magnesium salts.
The precipitated sodium chloride is recovered for sale and the
trine may be further evaporated to recover additional sodium
chloride values and is either stored, discharged back to salt
water or further worked to recover potassium and magnesium salts.
A process diagram is shown in Figure 18.
b) solution brine-mining process
Saturated brine for the production of evaporated salt is usually
obtained by pumping water into an underground salt deposit and
r emoving a saturated salt solution from an ad j acent
interconnected well, or from the same well by means of an annular
pipe. Besides sodium chloride, the brine will normally contain
some calcium sulfate, calcium chloride and magnesium chloride and
lesser amounts of other materials.
The chemical treatment given to brines varies from plant to plant
depending on impurities present. Typically, the brine may be
first aerated to remove hydrogen sulfide and, in many cases,
small amounts of chlorine are added to complete sulfide removal
and oxidize all iron salts present to the ferric state. The
brine is then pumped to settling tanks where it is treated with
soda ash and caustic soda to remove most of the calcium,
magnesium and iron present as insoluble salts. After
clarification to remove these insolubles, the brine is then sent
to multiple effect evaporators. As water is removed, salt
crystals form and are removed as a slurry. After screening to
remove lumps, the slurry is then washed with fresh brine. Ey
this washing, fine crystals of calcium sulfate are removed from
the mother liquor of the slurry and returned to the evaporator.
Eventually the calcium sulfate concentration in the evaporator
builds up to the point where it must be removed by "boiling out"
the evaporators.
The washed slurry is filtered, the mother liquor is returned to
the evaporators and the salt crystals from the filter are dried
and screened. Salt produced from a typical brine will be of 99.8
percent purity or greater. Some plants do not treat the raw
trine, but control the calcium and magnesium impurities by
watching the concentrations in the evaporators and bleeding off
39
-------
SEA WATER a 3° Be
1ST YEAR
CONCENTRATOR
BRINE a 7.5° 86
2ND YEAR
CONCENTRATOR
I
BRINE a 12° B6
3RD YEAR
CONCENTRATOR
BRINE a 16° Be
M/
4TH YEAR
CONCENTRATOR
BRINE a 20° Be
5TH YEAR
CONCENTRATOR
BRINE a 24.6° Be SATURATED (PICKLE)
SALT DEPOSITED
FOR HARVEST
CRYSTALLIZER
'T77///777,
•"I
I
RESIDUAL SALT
DISSOLVED IN
BRINE a 30° Be (BITTERN) SEA WATER
I
I
RESIDUAL SALT
DEPOSITED
HOLDING
' S ' '
/ /
\
POND
./•//>
BRINE a 32° Be
STORAGE POND
BITTERN STORAGE
FIGURE 18
STANDARD SOLAR SALT PROCESS
FLOW DIAGRAM
40
-------
minimal discharges into the environment and that exemplary sites
are not those which are exchanging one form of pollution for
another of the same or greater magnitude.
(e) Effluent treatment methods and their effectiveness
Plants selected generally have in use the best currently
available treatment methods, operating controls, and operational
reliability. Treatment methods considered included basic process
modifications which significantly reduce effluent loads as well
as conventional end-of-pipe treatment methods.
(f) Plant facilities
All plants chosen as exemplary had all the facilities normally
associated with the production of the specific chemical (s) in
question. These facilities, generally, were plants which have
all their normal process steps carried out on-site.
(g) Plant management philosophy
Plants were preferred whose management insists upon effective
equipment maintenance and good housekeeping practices. These
qualities are best identified by a high operational factor and
plant cleanliness.
(h) Diversity of processes
On the basis that all of the above criteria are met, consider-
ation was given to installations having a multiplicity of man-
ufacturing processes. However, for sampling purposes, the
complex facilities chosen were those for which the wastes could
be clearly traced through the various treatment steps.
(i) Product purity
For cases in which purity requirements play a major role in
determining the amounts of wastes to be treated and the degree of
water recycling possible, different product grades were
considered for sub-categorization.
Sampling of Exemplary Plants
The details of how the exemplary plants were sampled and the
analytical techniques employed are fully discussed in Section V.
GENERAL DESCRIPTION OF THE INDUSTRY
Brief descriptions of each of the twenty-two chemical
sutcategories are presented below. Process flow sheets for the
various subcategories are included. Production tonnages reported
for 1971 were taken from Current Industrial Reports, Inorganic
-------
Chemicals, U.S. Bureau of Census, Series M28A(71)-14.(1) These
values are summarized in Table 2- Also included are production
tonnages for years prior and subsequent to 1971, where available,
and the number of plants producing each chemical.
Aluminum Chloride
The anhydrous product is produced by the reaction of gaseous
chlorine with molten aluminum metal (scrap or scrap-pig mixture).
The basic equation is:
2A1 + 3C12 2A1C13
Chlorine is introduced below the surface of the molten aluminum.
The product sublimes and is collected by condensation. There are
three types of products manufactured, all from the same general
process;
(1) Yellow - this product is made using a slight excess of
chloride (0.0005 percent) and may contain some iron due
to reaction of the chloride with the vessel;
(2) White - this product has a stoichoimetric aluminum and
chlorine starting ratio; and
(3) Grey - this product contains 0.01 percent excess
aluminum. The unreacted aluminum raw waste lead is
higher for this grey material.
In most cases it makes little difference which of the above
grades is employed. In some pigment and dye intermediate
applications, the yellow material is preferred because it is free
of elemental aluminum.
Aluminum chloride is also made from the reaction of bauxite, coke
and chlorine. About 80 percent of all aluminum chloride made is
anhydrous. A solution grade of aluminum chloride is also
produced by reacting hydrated aluminum or bauxite ore with
hydrochloric acid. A standard process diagram is shown in Figure
1.
Annual U.S. production in 1971 totalled 26,399 kkg (29,100 tons).
The major use is as a catalyst in the petrochemical and synthetic
polymer industries.
The 1971 production for the 28 percent solution product was 7,650
kkg (8,400 tons).
Aluminum Sulfate
Aluminum sulfate is produced by the reaction of bauxite ore, or
other aluminum-containing compounds, with concentrated sulfuric
acid (60°Be). The general equation of the reaction is:
A1203 • 2H20 + 3H2S04-* A12 (S04) 3 + 5H20
10
-------
TABLE 2. .U.S. Production of Inorganic Chemicals (Metric Tons)
1973 (Est.) 1972
A1C13_
AljJL(SO,4_)3
CaC2.
CaCU.
ci2.(g)
HC1
HF
H£02
Li ml
H'N(U
K2Cr207
KOH " "
K
K2S04
NeTHCOJ.
9,480,031
2,131,873
6,731,276
I
91
Na,2C03., total ,
"Synthetic
NaCl
NaCl (Solar
3,991,592
)
30,844
l',019,670
447,240
86U821
8,952,052
1,996,703
301,184
68,039
6,369,311
;Estimated)4,309
161,478
6,768,470
3,929,904
NaCl (Solution Mining)
Na2Cr207 (&
NaOH "~
Na
Sodium Sili
N alSO 4
N a.2,S 0.3
H2.S04.
TiO£
Chromate)
9,797,544
cate
29,664,786
644,098
124,284
9,196,084
601,460
1,236,486
27,257,130
623,233
1971
26,399
1,084,080
566,988
1 ,100,409
8,483,947
1,904,171
199,126
58,060
6,116,208
179,622
59
407,959
158,756
6,396,526
3,878,194
2,350,000
5,928,000
125,191
9,276,006
138,799
569,709
1,230,136
185,065
26,691,000
615,068
1970
28,485
1 ,080,451
717,579
1 ,006,000
8,857,700
1 ,827,060
203,571
55 338
6,059,055
158,756
285
296,285
129,727
3,985,242
139,706
9,199,712
155,128
569,709
1,245,558
222,259
26,784,489
, 594,203
No. of
Plants
1969 (1971)
35,834 5
1 ,136,696 100
776,546 7
1,066,843 9
7,801 ,748 63
1 ,733,621 83
200,940 13
58,967 5
15,422,060 97
5,844,960 72
2
160,570 13
1
277,143 7
124,284 5
6,350,260 13
4,118,597 7
39,008,740 85
6
?
138,798 6
8,996,504 62
149,685 5
596,017 33
1,341,719 40
205,930 6
26,795,375 150
602,367 14
n
-------
CHLORINE
ALUMINUM
•*•*
s
•^
s
REACTOR
V
t
•**-
}
CONDENSER
N
t
PA1
WASTE
(DROSS, SOLID)
AICI3
PRODUCT
WASTE
GASES
PARTICULATE
AIC13)
(NaOH)
WATER VENT
SCRUBBER
WftSTE
AI(OH)3
(NaCI)
(NaOCI)
HCI
FIGURE l
STANDARD
ALUMINUM CHLORIDE FLOW DIAGRAM
-------
Ground ore and acid are reacted in a digester, from which the
products, aluminum sulfate in solution plus muds and other
insoluble materials from the ore, are fed into a settling tank.
The aluminum sulfate solution is then clarified and filtered to
remove any remaining insolubles. It may be sold as solution or
evaporated to yield a solid product. A typical process diagram
is shown in Figure 2.
Annual U.S. production in 1971 was 1,084,080 kkg (1,195,000
tens). Aluminum sulfate, or filter alum, is used for water
treatment (flocculation and clarification) and in treatment of
paper mill waste, sewage, and other waste streams.
Calcium Carbide
This chemical is prepared by the reaction of calcium oxide with
carbon (in the form of coke, petroleum coke, or anthracite) at
2000-2200°C <3632-3992°F) in a furnace similar to the familiar
arc furnace, as shown in Figure 3. The general equation for the
reaction is:
2CaO + 4C + Heat
2CaC2
02
Calcium carbide is used primarily in the manufacturing of
acetylene (by reaction with water). This use and the tonnage
production has been steadily decreasing. Still, many calcium
carbide plants are located in conjunction with acetylene plants.
Since the production process is dry, the only major discharges
are those effluents from scrubbing furnace and kiln offgases.
The U.S. production in 1971 was 567,182 kkg (625,338 tons).
Calcium Chloride
Most of the calcium chloride produced is extracted from impure
natural brines, but some of this salt is recovered as a by-
product of soda ash manufacture by the Solvay process. In the
manufacturing of calcium chloride from brine, the salts are
solution mined and the resulting brines are first concentrated to
reirove sodium chloride by precipitation and then purified by the
addition of other materials to precipitate sodium, potassium, and
magnesium salts. The purified calcium chloride brine is then
evaporated to yield a wet solid which is flaked and calcined to a
dry solid product. Extensive recycling of partially purified
brine is used to recover most of the sodium chloride values. A
standard process diagram is shown in Figure 4.
Manufacture of calcium chloride frcm Solvay process waste liquors
is similar to the natural brine process, except that the stepwise
concent ration and purif icat ion is unnece ssary because no
magnesium is present. Evaporation and calcining procedures are
similar to those above. Significant wastes result from calcium
chloride manufacturing.
13
-------
SULFURIC
ACID
BAUXITE
ORE
WASHOUT <
WASTES
(MUDS, AUSOA,
H2S04) 2 ™
1
DIGESTER
WASTE
(MUDS)
SETTLING
TANK
WASTE <-
(MUDS)
FILTRATION
STORAGE
LIQUID
ALUMINUM
'SULFATE
PRODUCT
EVAPORATION
SOLID
ALUMINUM
SULFATE
PRODUCT
STEAM
FIGURE 2
STANDARD PROCESS DIAGRAM FOR
ALUMINUM SULFATE MANUFACTURE
-------
COKE
COAL
LIMESTONE-
CRUSHING
i HOT AIR-
AIR-SWEPT
PULVERIZING
DRYING
CRUSHING
KILN
WOTER SPRAY
COOLER
A
AIR
GAS VENT
CARBIDE
FURNACE
_V
COOLING
CRUSHING
FIGURE 3
STANDARD
CALCIUM CARBIDE FLOW DIAGRAM
_v
STORAGE
GAS
SCRUBBER
WASTE
-------
SOLVAY WASTE LIQUOR,
OR PURIFIED BRINE '
MULTIPLE
EFFECT
EVAPORATOR
SODIUM
CHLORIDE
FINISHING
PAN
CALCIUM CALCIUM
CHLORIDE CHLORIDE
(SOLUTION) (SOLID)
FLAKER
FURNACE
CALCIUM
CHLORDE
(ANHYDROUS)
CALCIUM
CHLORIDE
(FLAKES)
FIGURE 4-
STANDARD PROCESS FOR CALCIUM CHLORIDE MANUFACTURE
-------
In 1971, U.S. production of calcium chloride was 1,101,281 kkg
(1,213,000 tons). Uses include de-icing of roads, use as a
stabilizer in pavement and cement, and dust control on roads.
Production is increasing as more uses and markets are found, but
potential production capability is much greater than that
presently utilized. Recently, increased recovery resulting from
pollution abatement measures has tended to cause calcium chloride
supply to exceed demand. Plants recovering this salt from
natural brines are located near mixed salt deposits, such as
those in Michigan, West Virginia, and California.
Calcium Oxide and Calcium Hydroxide
Calcium oxide is produced by calcining various types of limestone
in a continuous vertical or rotary kiln. The general equation
for the reaction is;
CaCOS + Heat-»-CaO + CQ2
Formerly coal or coke was used as fuel in vertical kilns, but in
recent years large gas-fired kilns have been widely used. After
calcination, the calcium oxide is cooled and then packaged or
crushed and screened to yield a pulverized product. It may be
slaked by reaction with water to yield calcium hydroxide and then
marketed. The only waterborne wastes result from wet scrubbing
of the gaseous kiln effluent to remove particulates. These
wastes are high pH liquors which also contain suspended solids.
The standard process diagram is shown in Figure 5.
Annual U.S. production of lime is believed to total about
16,000,000 kkg (17,600,000 tons). Approximately 20 percent of
this production is "captive" (made and consumed in the same
facility), primarily in the sugar, alkali, and steel industries.
The remainder finds a variety of chemical and industrial uses,
including use as an alkali and use in hydrated lime
manufacturing. Principal growth areas appear to be in basic
oxygen steel production and in soil stabilization.
Chlorine, sodium or Potassium Hydroxide
The major chlorine production results from the electrolysis of
sodium or potassium chloride brines, in which caustic soda (NaOH)
or caustic potash (KOH), respectively, are also produced. The
general equation for the electrolysis is (where M can be either
Na or K) :
dc
3 MCI + 2H2O-»-Cl2 + 2MOH + H2
From the above equation it can be seen that hydrogen is also a
by-product of brine electrolysis.
17
-------
LIMESTONE^
MIXING
CO
CALCINING
\t
COOLING
V
LIME
PRODUCT
{DRY SCRUBBER...WASTE
PRECIPITATOR WASTE
COLLECTION OR USE
LIME
WATER VENT
1 k
SLAKING
SCREENING
V
MILK OF LIME
Ca(OH)2
PRODUCT
RGURE 5
STANDARD
CALCIUM OXIDE (LIME) FLOW DIAGRAM
-------
Other sources (minor in size) of chlorine include the manufacture
of hydrochloric acid and metallic sodium.
Two types of electrolysis cells are used, mercury cells and
diaphragm cells.
a) Diaphragm cell process
In the diaphragm cell process. Figure 6, sodium chloride brines
are first purified by addition of sodium carbonate, lime
flocculating agents and barium carbonate in the amounts required
to precipitate all the magnesium, calcium and sulfate contents of
the brine. The brine is filtered to remove the precipitated
materials and is then electrolyzed in a diaphragm cell.
Chlorine, formed at one electrode, is collected, cooled, dried
with sulfuric acid, then purified, compressed, liquified and
shipped. At the other electrode, sodium hydroxide is formed and
hydrogen is liberated. The hydrogen is cooled, purified,
compressed and sold and the sodium hydroxide formed, along with
unreacted brine, is then evaporated at 50 percent concentration.
During partial evaporation, most of the unreacted sodium chloride
precipitates from the solution, which is then filtered. The
collected sodium chloride is recycled to the process and the
sodium hydroxide solutions are sold or further evaporated to
yield solid products.
In cases where potassium hydroxide is manufactured as a co-
product with chlorine, purified potassium chloride is used
instead of sodium chloride as the starting material. Otherwise,
the process is identical.
b) Mercury cell process
Figure 7 shows a standard process diagram for sodium hydroxide
and chlorine production by the mercury cell process. The raw
material salt, is dissolved and purified by addition of barium
chloride, soda ash, and lime to remove magnesium and calcium
salts and sulfates prior to electrolysis. The insolubles formed
on addition of the treatment chemicals are filtered from the
brine and the brine is fed to the mercury cell, wherein chlorine
is liberated at one electrode and a sodium-mercury amalgam is
formed at the other.
Mercury cells utilize mercury flowing along the bottom of a steel
trough as the cathode. A multiple anode is comprised of
horizontal graphite plates. Upon electrolysis the alkali metal
forms an amalgam with the mercury. The amalgam is decomposed
externally to the cell by the addition of water, which results in
the formation of hydrogen.
The chlorine gas from the cells is collected, cooled, dried by
contact with sulfuric acid, and then purified and liquified for
19
-------
WASTE
SOLAR
AND
DISSOLVE
\
/
V
WASTE
(PURIFICATION MUDS
CaC03,Mg(OH),ETC.)
NaCI
TO PROCESS
OR SALE
VENT
WASTE
(INSOLUBLES
IN SALT)
DIAPHRAGM
CELL
ELECTROLYSIS
NaOH
50% EVAPORATION
AND
NaCI RECOVERY
WASTE
(NaCI, NaOH}
98%
H2S04
SECONDARY
PURIFICATION
LOW
PURITY
CI2
SALE
WASTE WASTE
70%-80% (CHLORINATED
HS0
50%
->NaOH
SALE
HIGH
PURITY
SALE
NaOH
CONCENTRATION
SOLID
NaOH
SALE
X = PROPRIETARY INGREDIENTS
(POLYELECTROLYTES,
FLOCCULANTS, ETC. )
FIGURE 6
STANDARD
CHLORINE-CAUSTIC SODA FLOW DIAGRAM - DIAPHRAGM CELL PROCESS
-------
WASTE
TO PROCESS
WASTE
PURIFICATION
AND
COMPRESSION
X = PROPRIETARY INGREDIENTS
(POLYELECTROLYTES,
FLOCCULANTS, ETC.)
CI2 TO
VlQUlFICATION
5TE
CHLORINE-CAUSTIC
FIGURE 7
STANDARD
FLOW DIAGRAM MERCURY
CELL PROCESS
-------
shipment, utilized on-site, or sold as gaseous chlorine. Much of
the unreacted salt in the brine is recycled. Besides potential
caustic and brine effluents some mercury is present in the spent
brine from the mercury cell process. The cost of removing
mercury from the effluent accounts, to some extent, for the shift
back toward the diaphragm cells. Mercury cells began to be
widely used in the early 1950's and reached a high of almost 30
percent of the total production in 1968.
The U.S. production of chlorine in 1971 totalled 8,482,660 kkg of
gas (9,352,437 tons) and 4,035,489 kkg of liquid (4,449,271
tons). At present, about 75 percent of the production is in
diaphragm cells, 20 percent in mercury cells, and 5 percent from
other sources. About two-thirds of the production is utilized in
the synthetic organic chemical and plastics industries, and half
of that remaining is utilized in the pulp and paper industry (as
a bleaching agent). Other uses include the inorganic chemicals
industry, municipal water and sewage treatment, and many others.
Somewhat over half of the total production is "captive",
primarily in the synthetic organic chemicals and the pulp and
paper industries. In recent years proximity to markets has been
the major factor in chlorine plant location, in contrast to the
cost of power and salt which previously dominated plant
economics.
Sodium hydroxide is produced from the electrolysis of sodium
chloride brines in mercury or diaphragm cells as described above.
The caustic solution from the cathode of the electrolysis cell is
evaporated to about 50 percent by weight sodium hydroxide. This
may be sold as "standard-grade caustic liquor11, concentrated to
73 percent, or further refined through removal of chloride and
chlorate by various techniques. Refined caustic liquor may be
sold, further concentrated to 73 percent solids, or evaporated to
dryness. The anhydrous sodium hydroxide is sold in solid (flake
or powdered) forms. Most of the product is sold in the liquid
form.
Caustic soda has many varied uses, mostly as an alkali. It has
also replaced soda ash (sodium carbonate) in many uses, such as
in the aluminum industry and in other molten salt processes. It
is used to manufacture soda ash in one plant. In 1971, the U.S.
production of sodium hydroxide was 8,780,946 kkg (9,681,397 tons)
in liquid form and 493,393 kkg (543,983 tons) in solid form.
Production methods for potassium hydroxide are very similar to
those for sodium hydroxide, except that mined potassium chloride
brines are used as the raw material. In the mercury cell
process, the potassium-mercury amalgam is decomposed with water.
The mercury is recycled and the caustic solution is cooled and
filtered to recover potassium hydroxide.
-------
The U.S. production of potassium hydroxide in 1971 was 179,760
kkg (198,192 tons) . Caustic potash is used as an alkali,
particularly when very high purity is desired or where other
factors allow it to compete with sodium hydroxide (captive
production, for instance) . Other uses include the manufacturing
of potassium salts and organic compounds containing potassium.
Hydrochloric Acid
There are two major processes used for hydrochloric acid
manufacture. The process considered in this Document, as shown
in Figure 8, is direct reaction of chlorine with hydrogen by:
C12
;H2->2HC1
The second ma^jor souirce of production for hydrochloric acid, as a
by-^produpt of, drCranic dhlorination reactions , is the dominant
source,, Tnis process is. beyond the scope of this Document. By-
product hydrochloric acid is typically of lower purity than that
produced by direct reaction.
In the production of hydrochloric acid by direct reaction,
hydrogen and chlorine gases are reacted in a vertical burner.
The product hydrogen chloride so formed is cooled and then
absorbed in water. Exhaust gases are scrubbed, and acid values
are recycled. End products may include strong acid (22°Be) from
the cooler, weak acid (18°Be) from the absorber cclumn, a mixture
of these (20°Be) , or anhydrous HCl. The anhydrous acid may be
prepared by stripping gaseous HCl from strong acid. The
condensate and column bottoms from this process may * then be
recycled back into the hydrochloric acid recovery process.
Approximately 90. percent of the current production is byproduct,
and supply often exceeds demands Uses include pickling of steel,
chlorination reactions (in place of chlorine) , and a variety of
uses as an acid agent. Total U.S. production in 1971 was
1,904,075 kkg (2,099,371 tons),
Hydrofluoric Acid
Hydrofluoric acid is obtained by reacting the mineral fluorspar
(CaF2) with concentrated sulfuric acid in a furnace, as shown in
Figure 9. The general reaction for this process is:
CaF2 + H2SOU + Heat -* H2F2 * CaSOj*
The hydrofluoric acid leaves the furnace as a gas, which is then
cooled and absorbed in water prior to purification. In the
purification system, the crude acid is redistilled and either
absorbed in water to yield aqueous hydrofluoric acid or
compressed and bottled for sale as anhydrous hydrofluoric acid.
Final drying of the anhydrous gas is accomplished with
23
-------
HYDROGEN-
•9»
BURNER
PROCESS
WATER
COOLER
A
COOLING 22° Be
WTER ACID
PROCESS
WATER
VENT
/N
SCRUBBER
WEAK ACID
e 1_.
-------
V
r
—>
MIXER
V
REACTOR
WASTE
£•
HF
COOLER
I
V
DRIP POT
COKE BOX
CRUDE HF STORAGE
V
^
IWATERA
CONDENSER
A BRINE 1
1 \l/
V
CONDENSER
DISTILLER
BOTTOM ACID
STORAGE \ f
~]
STRIPPER
WASTE HF
PRODUCT
vj/
ACID ABORBERS
WATER
I ,
f
EJECTOR
I
CALCIUM
FLUORIDE. |
k-M
WATER
•>
HgS04 SCRUBBER
TAILS TOWER
V
WASTE
WATER
EJECTOR
|
ST
WASTE
- - >TO ACID STORAGE
WASTE
FIGURE 9
HYDROFLUORIC ACID FUOW DIAGRAM
-------
concentrated sulfuric acid.
70 percent acid.
Aqueous acid is normally shipped as
Most U.S. hydrofluoric acid production (probably 75-80 percent)
is captive to the fluorinated organics and plastics industries.
Total U.S. production in 1971 was 199,069 kkg (219,481 tons), and
the production appears to be increasing fairly rapidly.
Fluorinated organics and plastics comprise the major use
industries. Another major use is in the production of synthetic
cryolite and aluminum fluoride. Most of the acid-grade fluorspar
ore is imported. Waste disposal problems and safety hazards are
specialized and severe because of the reactivity of the material.
Hydrogen Peroxide
Hydrogen peroxide is manufactured by three different processes:
(1) An electrolytic process; (2) Oxidation of alkyl
hydroanthraquinones; and (3) As a by-product in the manufacturing
of acetone from isopropyl alcohol. This Document includes
processes (1) and (2) .
a) Electrolytic process
In the electrolytic process, a solution of ammonium (or other)
bisulfate is electrolyzed, yielding ammonium persulfate at the
ancde and hydrogen gas at the cathode. The persulfate is then
reacted with water (hydrolyzed) to yield hydrogen peroxide and
the original bisulfate. The general reaction scheme is:
dc
2NH4HS04
(NHU)2S20£ + H20-
• (NHU)2S208 + H2
•2NH?HS04 + H202
The crude peroxide product emerges mixed with water, and can be
concentrated to desired levels by vacuum distillation or low-
temperature fractionation. The cathode liquor is filtered and
reused. A standard flow diagram is shown in Figure 10,
b) Organic process
The alkylhydroanthraquinone oxidation process is shown in general
form below ("R" represents the alkylanthraquinone molecule,
except for the two double-bonded oxygens):
O=R=O
HO-R-*OH
H2
02
Cat.
>• HO-R-OH
H202
In this process, the alkylanthraquinone is reduced by hydrogen
over a supported metal catalyst (typically palladium on alumina),
the product being the corresponding alkylhydroanthraquinone.
This, in turn, is oxidized by oxygen in a forced gas stream to
26
-------
COOLING WATER
AMMONIUM
SULFATE ~
~
HYDROGEN
PEROXIDE
(30%)
HYDROGEN
PEROXIDE
(80-85%)
-------
reform the original alkylanthraquinone plus hydrogen peroxide.
The hydrogen peroxide is extracted with water and the
alkylanthraquinone is recycled. The recovered product is then
concentrated, purified, and sold. A general process diagram for
the organic process is shown in Figure 11.
Hydrogen peroxide is sold in a range of aqueous concentrations
from three percent to 98 percent by weight. The higher con-
centration materials are dangerously reactive. A stabilizer
(such as acetanilid) is typically added to the product to retard
decomposition. Uses include bleaching of textiles and paper,
epoxidation, production of peroxy-acid catalysts, oxidation of
organic compounds, formation of foams, and a source of energy for
both military and civilian applications. The U.S. production in
1971 was 57,937 kkg (63,878 tons).
Nitric Acid
This document covers production of nitric acid in concentrations
up to 68 percent by weight (azectropic concentration). More
concentrated nitric acid, including fuming nitric acid and
nitrogen pentoxide will be included in the phase II Document.
The production of nitric acid by the reaction of sodium nitrate
and sulfuric acid is also not included.
Nitric acid is produced by the catalytic oxidation of ammonia,
first to nitric oxide (NO), and then to nitrogen dioxide (NO2),
which is reacted with water under pressure to form the acid as
shewn in Figure 12. The overall reaction scheme is:
cat.
4NH3 +• 5O.2—*• 4NO + 6H20
2NO +02 —>- 2N02
3N02 + H20 —+- 2HN03 + NO
In the process, compressed, purified, and preheated air and
anhydrous ammonia are mixed and passed over a platinum rhodium
wire-gauze catalyst at about 750°C (1382°F). The resultant
mixture of nitric oxide and excess air is introduced, along with
additional air, into a stainless steel absorption tower in which
the nitric oxide is further oxidized. The resulting nitrogen
dioxide is reacted with water. The bottm of the tower yields 61
- 65 percent by weight nitric acid.
Most of the U.S. nitric acid production is utilized in the
fertilizer industry. The second largest use is in explosives
manufacturing. Various uses as an acidic or pickling agent
account for much of the remaining production. Total U-S.
production in 1971 was 6,151,112 kkg (6,742,130 tons).
28
-------
RANEY
NICKEL
CATALYST HYDROGEN
^ ^
>-
o
u.
O
z
en
o
IVERTED THUS
o
UJ
m
0
u.
i
1
UJ
X
t-
u_
o
1
o
en
o
"
r~
YDR06ENA-
N
TOR FILTER
f
FILTER.
A \
COOLING
WATER
' V
COOLER
uuuuuuu
N
f
OXIDIZING
VESSEL
WATER
^ N
f
EXTRACTION
TOWER
N
^— OXYGEN
,20-25% HgOg
RECYCLE y
, 15% OF PRODUCT 50^
' \t
DRYING TOWER
>
f
CLAY BED
>
f
NICKEL-SILVER
CATALYST BED
PURGE
WASTE
FIGURE ±±
STANDARD
HYDROGEN PEROXIDE FLOW DIAGRAM
(RIEDL-PFLEIDERER PROCESS)
-------
WASTE
WATER GASES
A
AMMONIA
(ANHYDROUS)
EVAPORATOR
REACTOR
AIR
COMPRESSOR
COOLER
WEAK ACID
FILTER
AIR
ABSORBER
NITRIC ACID
(61-65%)
FIGURE
STANDARD NITRIC ACID PROCESS FLOW DIAGRAM
-------
Potassium Metal
Potassium is produced by the reaction of potassium chloride with
sodium vapor: ;
KC1 + Na + Heat — > K -*• NaCl
For the commercial preparation of potassium metal, potassium
chloride is melted in" a gas fired melt pot and fed to an exchange
column as shown in Figure 13, The molten potassium chloride
flews over Raschig rings in the packed column, where it contacts
ascending sodium vapors coming from a gas-fired reboiler. An
equilibrium is established between the two, yielding sodium
chlor:ide "and elemental potassium. The sodium chloride formed is
continuously withdrawn at the base of the apparatus and is
normally sold. The column operating conditions may be varied to
yield either pure potassium metal as an overhead product or to
vaporize sodium along with the potassium to produce sodium-
potassium (NaK) alloys of varying compositions. Potassium metal
of over 99,5 percent purity can be continuously produced.
Since it is relatively more reactive than sodium, the reaction
between potassium and carbon (plus a tendency to form explosive
carbonyls) precludes the manufacture of potassium by
electrolysis. Because it is more expensive than sodium,
potassium has very limited uses. Major uses include manufacture
of organo-potassium compounds and production of NaK (sodium
potassium alloys used in lard modification and as a nuclear
reactor coolant). Total U.S. production in 1972 was about 100
kkg (110 tons) , primarily from one facility.
Potassium Dichromate
Most of the potassium dichromate manufactured in the U.S. is
made by reacting a sodium dichromate dihydrate solution with
potassium chloride according to the following:
Na2Cr207«2H20
2KCl-»-K2Cr207 -*• 2NaCl
2H20
Potassium chloride is added to a dichromate solution, which is
then pH adjusted, saturated, filtered and vacuum cooled to
precipitate crystalline potassium dichromate which is recovered
by centrifuging, dried, sized and packaged. The mother liquor
from the product centrifuge is then concentrated to precipitate
sodium chloride which is removed as a solid waste from a salt
centrifuge. The process liquid is recycled to the initial
reaction tank. Figure 14 is the standard process diagram. A
relatively pure product results which reguires only removal of
the water prior to sizing and packaging.
The major uses of potassium dichromate are as a glass pigment and
a photographic development chemical. Estimated annual production
in the U.S. is 4,000-4,500 kkg (4,400-5,000 tons).
31
-------
K (OR NaK) VAPOR
COLUMN
MOLTEN KCI
Na
TRAP
HEAT
NaCt (SOLD)
Na VAPOR,
N2
V
STAINLESS
STEEL
RASCHIG
RINGS
Nad
SLAG
WITH
Na
_PJB^ \S
'"' SLAG?^"
RECEIVER
HEAT
V
CONDENSATION
I
K
(OR
NaK ALLOY)
< HEAT
FIGURE 13
COMMERCIAL EXTRACTION OF POTASSIUM
32
-------
O)
RECYCLED LIQUOR
SODIUM
DICHROMATE
LIQUOR
KCI
FROM
RIVER
TO
RIVER
MOTHER
LIQUOR
SALT
CONCENTRATOR
(STEAM
HEATED)
SALT
CENTRIFUGE
SODIUM
CHLORDE
SOLID
WVSTE
FIGURE 14
STANDARD POTASSIUM DICHROMATE PROCESS RJOW DIAGRAM
-------
SODA ASH WATER
r
i
WASTE
CHARGING
MIXING
FEEDING
CARBONATING
V
CENTRIFUGING
V
DRYING
COLLECTING
V
SCREENING
AND/OR
MILLING
VENT
C02
PRODUCT
TO
STORAGE
PRODUCT
•TO
STORAGE
RGURE 16
STANDARD SODIUM BICARBONATE PROCESS
FLOW DIAGRAM
3b
-------
SODIUM
DICHROMATE
LIQUOR
KCt
RECYCLED UQUOR
FROM
RIVER
TO
.RIVER
MOTHER
UQUOR
SALT
CONCENTRATOR
(STEAM
HEATED)
SALT
CENTRIFUGE
SODIUM
CHLORIDE
SOLID
VASTE
FIGURE 14.
STANDARD POTASSIUM DICHROMATE PROCESS FLOW DIAGRAM
-------
Potassium Sulfate
The bulk of the potassium sulfate manufactured in the U.S. is
prepared by the treatment with potassium chloride of dissolved
langbeinite, a naturally-occuring potassium sulfate-magnesium
sulfate mineral, K2SOtl»2MgSO£. Mined langbeinite is crushed and
dissolved in water to which potassium chloride is added. Partial
evaporation of the solution results in selective precipitation of
potassium sulfate which is recovered by centrifugation or
filtration, dried, and sold. The remaining brine liquor is
either discharged to an evaporation pond, reused as process
water, or evaporated. Magnesium chloride may be economically
recovered as a byproduct if the raw material is of sufficiently
high quality. A standard process diagram is shown in Figure 15.
Current annual production in the U.S. is 407,916 kkg (449,742
tons). Much of this finds agricultural use, particularly for
tohacco and citrus.
Scdium Bicarbonate
Sodium bicarbonate, also known as baking soda, is made by the
reaction of sodium carbonate with water and carbon dioxide under
pressure, as shown in Figure 16. The bicarbonate so formed
precipitates from the solution and is filtered, washed, dried,
and packaged. The general process reaction is:
Na2C03 + H20 + C02->-2NaHC03
Sodium bicarbonate is typically a minor by-product of soda ash
manufacturers.
Total U.S. production in 1971 was 158,305 kkg (174,537 tons).
Major industrial users include food processors, chemical plants,
pharmaceutical producers, synthetic rubber manufacturers, leather
processors and paper and textile producers. It is also used in
fire extinguishers to form carbon dioxide and in food
preparation.
Sodium Carbonate
Scdium carbonate, or soda ash, is produced by the "solvay"
process and by mining naturally-occuring deposits in California
and Wyoming. Production by mining is less than that from the
Solvay process. In the mining process, trona (sodium
sesquicarbonate, Na2CO3«NaHCO3«2H20) is brought tc the surface in
solid form, crushed and ground, and dissolved in water. The
solution is clarified, thickened, filtered, and sent to vacuum
crystallizers, from which part of the soda ash is recovered in
solid form. The remaining solution is cooled to precipitate
additional soda ash and bicarbonate. These solids are then
dewatered and calcined to yield soda ash.
34
-------
MINING
CRUSHING
V
LEACHING
DEWATERING
DRYING
PRODUCT SIZING
STANDARD
V
GRANULAR
SUSPENSION
PROCESS K-MAG
K-MAG (K2S04-;MgS04)
V
GRINDING
HYDRATION
MURIATE (KCI)
EVAPORATION
REACTION
.BRINE
WASTE
DRYING
V
REACTION SOLIDS
(HIGH GRADE K2S04}
GRANULATION
V
PRODUCT SIZING
STANDARD
\L
GRANULAR
FERTILIZER GRADE SULFATE
FIGURE 15
STANDARD POTASSIUM SULFATE PROCESS DIAGRAM
35
-------
SODA ASH WATER
r
|L
WASTE
CHARGING
MIXING
FEEDING
CARBONATING
CENTRIFUGING
DRYING
COLLECTING
SCREENING
AND/OR
MILLING
VENT
C02
PRODUCT
TO
STORAGE
PRODUCT
•TO
STORAGE
FIGURE ie
STANDARD SODIUM BICARBONATE PROCESS
FLOW DIAGRAM
3b
-------
The solvay process, as shown in Figure 17, involves a reaction in
aqueous solution (under pressure) between ammonia, brine (Nad) ,
and carbon dioxide to yield sodium bicarbonate, which is then
converted to soda ash by heating. Ammonia is recovered by the
addition of slaked lime to the used liquor. The general reaction
is as follows:
Formation of Ammonium Bicarbonate
NH3 + H2O-^NH4OH
NH40H + C02-^MH4HC03
Conversion to Sodium Bicarbonate
NH4HC03 + NaCl-»~NaHC03 + NH4C1
Conversion to Soda Ash
2NaHC03 + Heat-*-Na2C03
C02
H20
Recovery of Ammonia
CaCl2
H20
The saturated brine is purified of other metal ions by preci-
pitation, and then picks up ammonia in an absorber tower.
Amimoniated trine is reacted with carbon dioxide in a carbonating
tower, and the resulting bicarbonate precipitates as the sodium
salt, forming a slurry. The slurry is filtered to remove the
solid bicarbonate which is calcined to yield the light ash
product. Dense ash is made by successive hydration and
dehydration of the light ash. The carbon dioxide and ammonia are
recycled. calcium chloride is also being recovered now in some
plants.
Many soda ash plants are associated with producers of glass
(largest user industry) or with sources or raw material such as
ccke-oven plants {by-product ammonia) , the cement industry
(utilization of lime sludge) , or solid carbon dioxide producers.
Soda ash competes with caustic soda and other chemicals in a
variety of applications other than glass manufacture. Large
amounts are used in the non-ferrous metals industry and in the
production of bicarbonate and washing soda. Several types of
products are sold commercially. Production figures for the U.S.
in 1971 are as follows:
Finished Light Ash
Finished Dense Ash
Natural Ash
Total
Sodium Chloride
1,676,621 kkg (1,848,535 tons)
2,120,467 kkg (2,337,891 tons)
2,598,321 kkg (2,864,742 tons)
6,395,409 kkg (7,051,168 tons)
Large quantities of this chemical
seawater by three basic processes:
are produced from brine or
37
-------
STEAM + C02
BRINE-
BRINE
PURIFICATION
WASTE
(PURIFICATION MUDS,
CaC03,Mg(OH)2,ETC.)
REACTOR
C02
LIME
KILN
LIMESTONE-
COKE
PRECIRTATOR
WATER
vL_
1
CALC1NER
SODA ASH
STORAGE
SPENT BRINE
NH4CI
SLAKER
NH3
STILL
RECYCLE NH3
n
WASTE(CaCI2 AND NaCI)
T—'OPTIONAL CaCIa RECOVERY
EVAPORATOR
DRYNG
5TE CaCI2
FIGURE 17 L^tNaC^CaCy _PRODUCT_J
SOLVAY PROCESS SODIUM CARBONATE FLOW DIAGRAM
-------
(1) solar evaporation of brine;
(2) solution mining of natural salt; and
(3) conventional mining of rock salt.
a) Solar evaporation process
In the solar evaporation process, salt water is concentrated by
evaporation over a period of several years in open ponds to yield
a saturated brine solution. After saturation is reached, the
brine is then fed to a crystallizer, wherein sodium chloride
precipitates, leaving behind a concentrated brine solution
(bittern) consisting of sodium, potassium and magnesium salts.
The precipitated sodium chloride is recovered for sale and the
trine may be further evaporated to recover additional sodium
chloride values and is either stored, discharged back to salt
water or farther worked to recover potassium and magnesium salts.
A process diagram is shown in Figure 18,
b) Solution brine^mining process
Saturated brine for the production of evaporated salt is usually
obtained by pumping water into an underground salt deposit and
removing a saturated salt solution from an adjacent
interconnected well, or from the same well by means of an annular
pipe. Besides sodium chloride, the brine will normally contain
some calcium sulfate, calcium chloride and magnesium chloride and
lesser amounts of other materials.
The chemical treatment given to brines varies from plant to plant
depending on impurities present. Typically, the brine may be
first aerated to remove hydrogen sulfide and, in many cases,
small amounts of chlorine are added to complete sulfide removal
and oxidize all iron salts present to the ferric state. The
brine is then pumped to settling tanks where it is treated with
soda ash and caustic soda to remove most of the calcium,
magnesium and iron present as insoluble salts. After
clarification to remove these insolubles, the brine is then sent
to multiple effect evaporators. As water is removed, salt
crystals form and are removed as a slurry. After screening to
remove lumps, the slurry is then washed with fresh brine. Ey
this washing, fine crystals of calcium sulfate are removed from
the mother liquor of the slurry and returned to the evaporator.
Eventually the calcium sulfate concentration in the evaporator
builds up to the point where it must be removed by "boiling out"
the evaporators.
The washed slurry is filtered, the mother liquor is returned to
the evaporators and the salt crystals from the filter are dried
and screened. Salt produced from a typical brine will be of 99.8
percent purity or greater. Some plants do not treat the raw
hrine, but control the calcium and magnesium impurities by
watching the concentrations in the evaporators and bleeding off
39
-------
SEA WATER o 3° B*
1ST YEAR
CONCENTRATOR
BRINE a 7.5° B&
M/
2ND YEAR
CONCENTRATOR
I
BRINE a 12° Bi
M/
3RD YEAR
CONCENTRATOR
BRINE a 16° Bi
4TH YEAR
CONCENTRATOR
I
BRINE a 20° Bi
M/
5TH YEAR
CONCENTRATOR
BRINE a 24.6° B4 SATURATED (PICKLE)
SALT DEPOSITED
FOR HARVEST
CRYSTALLIZER
1
I
RESIDUAL SALT
1 DISSOLVED IN
BRINE a 30° B* (BITTERN) SEA WATER
RESIDUAL SALT
DEPOSITED
HOLDING POND
x /
e^
i
BRINE a 32° Bi
STORAGE POND
BITTERN STORAQE
FIGURE 16
STANDARD SOLAR SALT PROCESS
FLOW DIAGRAM
40
-------
The raw material bauxite contains 54-56 percent of soluble &12Q3,
about 3.5 percent Ti02, about 5.5 percent SiO2, about 1.5 percent
Fe2O3 and the rest water of hydration. The muds have,
approximately, the following compositions: 40 percent Sio^* 40
percent TiO2, 20 percent A12O3, 0.5 percent A12(SO4)3.
At these plants, all waters are fed to a settling basin where
muds are removed and impounded. The clear effluent is then
reused in the process. Provisions are established for collection
of all leaks and spills which are pumped to the impoundment,
treated and recycled. A breakdown of water use at both
facilities is shown below:
Quantity
Plant cu m/day 1/kkg
Comments
049 47 (12,400 1650 (396 gal/ton) No Pretreatment
gpd) Required for
063 76 (20,000 2090 (500 gal/ton) Either
gpd)
Process Water Quantity
Type Plant cu m/dav 1/kkg
Process 049
Percent of Process
im
30*
77 (20,400 2720 (652 gal/ton)
gpd)
Process 063 87 (23,000 2400 (575 gal/ton) All excess pro-
gpd) cess water*
*Remaining water shipped with product. Aluminum sulfate sol-
utions are made at both plants.
These plants have no process or cooling water effluent.
Calcium Carbide
Calcium carbide is manufactured by the thermal reaction of
calcium oxide and coke. Calcium oxide and dried coke are reacted
in a furnace, and the product is then cooled, crushed, screened,
packaged and shipped. The only wastes from the process are air-
borne dusts from the furnace, coke dryer and screening bag
filters. Bag filters are now being installed in the furnace and
the packing areas of plant 190. All collections are returned to
the furnace. The process locations of the sources of raw waste
in plant 190 are shown in Figure 33. A listing of the raw wastes
and amounts is given below. All but the cooling tower blowdowns
are treated by dry collection methods. The blowdown wastes are
intermittent and are currently untreated. This data was fur-
nished by the manufacturer.
73
-------
LIME
SILO
COOLING
WATER
PET-
COKE
DRYER
SILO
FURNACE
COLLECTOR
t
COOL
CRUSH
SCREEN
PACKAGE
COLLECTOR
V V
SHIP
COLLECTOR
FIGURE 33
CALCIUM CARBIDE PROCESS FLOW DIAGRAM AT PLANT 190
-------
Waste Product
1. Fine Petroleum Coke
2. Stack Dust
3. Packing Dust
4. Cooling Tower Slowdown
Solids and Cooling Water
Treatment Chemicals
kq/kkg of Product (Ib/ton)
Range
30-70 (30-140)
70-115 (140-230)
6-11 (12-22)
0.5-1 (1-2)
50 (100)
85 (170)
10 (20)
The first waste is collected by bag filters and recycled. Waste
products 2 and 3 are now being exhausted to the air but will fce
collected and recycled by bag filters similar to those now
collecting the coke fines. The fourth waste is currently
untreated.
Figure 34 shows, schematically, the source and disposition of the
water uses at this plant. Table 3 lists the effluent waste data
supplied by plant 190 and verification measurements. (These data
are the same as presented to the Corps of Engineers in plant
190's permit application, except for pH and flow, which were
obtained during a plant visit).
Considerable amounts of chlorides and sulfates are discharged
intermittently due to cooling tower blowdowns and use of water
treatment chemicals.
Plant 190's policy is to recover and recycle all possible air-
borne dusts by dry collection techniques. This approach
eliminates all process water wastes. The cooling tower blowdown
and incoming water treatment regenerants are the only water
effluents. There is no process waste water effluent in this
exemplary plant.
Calcium Chloride
Calcium chloride is produced by extraction from natural brines.
Seme material is also recovered as a by-product of soda ash
manufacture by the Solvay process. The latter will be discussed
in the soda ash section.
In the manufacture of calcium chloride from brines, the salts are
solution mined and the resulting brines are first partly
evaporated to remove sodium chloride by precipitation. The brine
is further purified by addition of other materials to remove
sodium, potassium and magnesium salts by precipitation and
further evaporation. It is then evaporated to dryness to recover
calcium chloride which is packaged and sold. Figure 35 shows the
detailed separation procedure used at plant 185. Bromides and
iodides are first separated from the brines before sodium
chloride recovery is performed. There is a large degree of trine
75
-------
DOMESTIC SEWAGE
PROCESS TREATED WATER
TOTAL
RETENTION
LAGOON
^-FURNACE
LAB.
MAINT.
CITY WATER
SLOWDOWN-
FIGURE 34
WATER USAGE AT PLANT 190
CALCIUM CARBIDE FACILITY
76
-------
TABLE 3. Plant Effluent from CaC£ Manufacture
{All units ppm unless specified)
Parameter
Total suspended solids
Flow (cu m/day)
Total dissolved solids
Conduct!vi ty (as NaCl)
BOD
COD
pH
Alkalinity (as CaCO.3)
Nitrate (as N)
Zinc
Phosphorus Total (phosphate)
Color (APHA Units)
Aluminum
Turbidity (FTU)
Fluoride
Total hardness (as CaCOJ.)
Calcium hardness (as CaCOS.)
Sulfate ""
Chioride
Iron
Chlorine (as C12)
Intake Water
Plant
Data Verifcn
Cooli ng
Tower Water
Plant
Data
3.5
152
238
(c)
80
15
7.6
99
0.45
0.01
0.27
Nil
0.15
0
0.45
140
(c)
55
46
0.03
(c)
0
(a,b)
(a)
95-100
(a)
25
7.5
90
0.27
(a)
0.32
10
(a)
5
(a)
136
118
51 .5
36
0.08
0
48
13
1930
(c)
308
170
7.6
68
12
2.8
0.55
675
0.17
18
0.95
404
(c)
290
198
(c)
Venfcn
0
(a,b)
(a)
810
(a)
75
8.0
165
9.8
(a)
1.30
20
(a)
10
(a)
750
675
690
95
0.019
0.1
(a) Not measured
(b) Flow varied frequently
monitoring valve
(c) Not in furnished data.
depending on response of level-
Note: Above data are not from split samples, but represent data
furnished for Corps of Engineer permit application approx>
imately two years prior to the verification measurements.
77
-------
BRINE
WELL"
SEPARATOR
IODIDES. BROMIDES AND
MAGNESIUM TO OTHER PROCESSES
INVENTORY
COOLING
WATER _
\/
EVAPORATOR
WTTE
WASTE
-TCONDENSATE
V V
• STEAM
>CONDENSATE
NaCI SEPARATOR
LIQUOR
38% SOLUTION
PROCESS
WATER
NaCI D1SSOLVER
CaCIo (SOLUTION)
PURIFICATION
VENT TO.
EXHAUST
'COOLING
WATER
TO CHLOR-ALKALI
COOLING WATER
FROM PROCESS
SCRUBBER
WASTE
r
EVAPORATOR
_v
FLAKER AND DRYER
-STEAM
•CONDENSATE
COOLING
.WATER
COOLING
TOWER
L^B <«_ ^— —«™- ™™
V
WASTE
ANHYDROUS PRODUCT
FIGURE 35
CALCIUM CHLORIDE FLOW DIAGRAM
AT PLANT 185
78
-------
recycling to remove most sodium chloride values,
of the trine is:
The composition
CaC12
MgC12
NaCl"
KC1
Bromides
Other minerals
water
19.3 percent
3-1 percent
4.9 percent
1,4 percent
0.25 percent
0.5 percent
70.6 percent
The raw wastes expected from calcium chloride manufacture at
plant 185 arise from blowdowns as well as from the several
partial evaporation steps used. Most of the wastes are weak
brine solutions:
Waste Products
NH3
CaCl2
Nad""
Gael 2
^ KC1
*NaCl
Process Source
Evaporators
Evaporators
Evaporators
Packaging
Brine separation
Secondary Brine Separation
Avg. kg/kkg of
Product (Ib/tonl
0.55
29
0.5
0.7
45.5
110
(1-1)
(58)
(1.0)
(1.4)
(91)
(220)
*Fecycled or used elsewhere.
At plant 185r the waste brine streams are passed through an
activated sludge treatment to remove organics and are then passed
to a settling basin to, remove suspended matter, adjusted to
neutral pH, fed into a second pond to further settle suspended
matter, and finally discharged. Future plans at plant 185 call
for changes in the evaporators to reduce calcium chloride
discharges and eliminate ammonia from the discharges. More
recycling of spent brines is also planned. Table 4 gives a
detailed breakdown of current water usage at plant 185.
Table 4A lists the river intake and effluent compositions at
plant 185. The effluent consists mostly of weak brine solutions
(neutral pH).
Calcium oxide and Calcium Hydroxide
Calcium oxide is manufactured by thermal decomposition of
limestone in a kiln. The limestone is first crushed, then added
to the kiln, wherein it is calcined to effect decomposition. The
product is then removed from the kilns, marketed as is, or
slaked by reaction with water to produce calcium hydroxide. A
process flowchart is given in Figure 36 descriptive cf the
general process at plant 007.
79
-------
TABLE 4. Plant 185 Water Flows
Inputs
Type
River (+ 442!)
Lake
cu m/day (MGD)
208}
144)
31,100 (8.208
545 (0.
Uters/kkg (gal/ton)
62,700 (15,000)
1 ,100 (263)
Water Usage
Type cu m/day _(MGD) Uters/kkg fgal/ton) % Recycled
Cooling
Process
Washdown
Washout
58,500
164,000
2,180
680
15.5)
43.2)
0.576)
0.180)
118,000
330
4,390
1,370
28.300)
79)
1,052)
329)
46
0
0
10
TABLE
Parameter*
Composition of
of Plant 185
Intake and Effluent Stream
Intake
Effluent Stream No. 1
Flow, cu m/day (MGD)
Plant
Data
31,600
(8.35)
42
353
3
8.3
5.3
20
476
200
no
0.2
0.1
0.2
0.4
0.1
0.05
0.1
160
Verification
Measurement
**
8
293
Plant
Data
31,600
(8.35)
2,693
1.1
Verification
Measurement
**
29
309
Total Suspended Solids
Total Dissolved Solids
BOD
COD -
pH 8.3 8.3 6.7-8.0 9.1
Turbidity (FTU) 5.3 0 18.2 25
Color (ALPH Units) 20 70 60 80
Conductivity (Nad) 476 520 5,390 340
Hardness (Ca) 200 179 700 169
Sulfate 110 36 312 36
Nitrate 0.2 0.29 0,2 20
Ammonia 0.1 0.60 2.0 8.8
Organic Nitrogen 0.2 - 2.7
Iron 0.4 0,30 1.0 0.09
Copper
Chromate 0.1 - 0.1
Manganese 0.05 - 0.1
Zinc 0.1 - 0.85
Total Alkalinity (CaCO£) 160 170 67 235
* mg/1 unless otherwise specified
**measurement not possible due to physical constraints of location
Note: Above data not split samples; plant data furnished separately,
prior to sampling for verification.
80
.
-------
VENT
LIMESTONE
NATURAL GAS
KILN
COg,, KILN GASES>
PARTICULATE
MATTER
1
DRY
BAG
COLLECTORS
AIR
COOLER
QUICKLIME
VENT
A
SOLID
WASTE
MAKE-UP
WATER
HAMMER
MILL
DRY
BAG
COLLECTOR
COOLING WATER
COOLING
TOWER
HYDRATOR
PRODUCT RECOVERY
_v
BULK
HYDRATED
LIME
STORAGE
-PROCESS WATER
NON-CONTACT
COOLING WATER
PARTICLE
SIZING
HYDRATED
LIME
PACKAGING
FIGURE 36
FLOW DIAGRAM FOR LIME PLANT 007
81
-------
The raw wastes produced from calcium oxide manufacture are shown
below. The quantities of waste are not affected by process
startup or shutdown- These consist of fine dusts collected from
the plant gas effluent by scrubbing systems. At the exemplary
facility, this dust removal is achieved by use of bag filters and
other dry particulate collection equipment. No wet scrubbing
techniques are employed. Wet scrubbing of these dusts is used
commonly at other plants.
Waste Product
Dry Particulate Matter
Proce.ss Source
Kiln gases
(Dry collector)
kg/kkg of
Product fib/ton)
67 (133)
Exemplary plant water usage is described below. All cooling
water is recycled and all product water is consumed in the
manufacture of calcium hydroxide. Due to the use of dry waste
collection techniques, there is no waterborne effluent from the
facility. This plant achieves ninety-five percent or tetter
solids collection at the kiln collector. Municipal water intake
to the plant amounts to 638 1/kkg (153 gal/ton) of product plus
the amount evaporated in the cooling tower. This water is not
further treated in the plant prior to use.
This water represents the process water, which is used in the
hydrator. The cooling water flow for the bearings on the tube
mill and pistons on the hydrator pump amounts to 1000 1/kkg of
product (240 gal/ton). It is completely recycled with makeup
water added to compensate for evaporation.
Chlorine and Sodium or Potassium Hydroxide
a) Mercury cell process
Caustic and chlorine are produced from sodium chloride or
potassium chloride raw materials in the mercury cell process,
depending on whether caustic soda or caustic potash is to be pro-
duced. The raw material is dissolved and purified by addition of
barium carbonate, soda ash, and lime to remove magnesium and
calcium salts and sulfates prior to electrolysis. The insolubles
formed on addition of the treatment chemicals are filtered from
the brine. The brine is then fed to the mercury cell, wherein
chlorine is liberated at one electrode and a sodium-mercury
amalgam is formed at the other.
The chlcrine formed is cooled, dried in a sulfuric acid stream,
purified to remove chlorinated organics, compressed and sold.
The mercury-sodium amalgam also formed during electrolysis is
sent to a "denuder" where it is treated with water to decompose
the amalgam. Sodium hydroxide and hydrogen are formed in the
reaction. The mercury liberated is returned to the electrolysis
82
-------
cells. The hydrogen is cooled,
mercury, compressed and sold.
scrubbed to remove traces of
The sodium hydroxide formed at the
concentrated, and sold. Brines emerging
cells are concentrated and recycled.
denuders is filtered,
from the electrolysis
Two exemplary facilities, plants 130 and 144, and one qualified
exemplary facility, plant 098, have been selected and studied in
detail. Plant 130 produces potassium hydroxide and plants 144
and 098 produce sodium hydroxide. Plant 098 is considered as an
exemplary plant with the qualification that it is located outside
of the United states. It is included because its mercury
recovery system is of special note. The process flow diagram for
plant 130 is shown in Figure 37.
Raw waste loads for this process are presented in Table 5, which
gives overall figures based on twenty-one facilities, plus
partial data as furnished- from plants 098 and 130. The chief raw
wastes include purification muds (CaCO3, Mg(OH)2 and BaSC4) from
brine purification, some spent brine materials from caustic
recovery, and condensates from chlorine and hydrogen
compressions. The sulfuric acid used to dry the chlorine is not
a waste in plant 130 as it is recovered for sale.
In the caustic potash plant, plant 130, the brine muds and
potassium chloride make up the bulk of the primary waste. A
small amount of copper sulfate catalyst is also wasted. This
catalyst is used in treatment of waste chlorine. Specifically,
the chlorine is reacted with excess sodium hydroxide in the
presence of copper sulfate to produce sodium chloride, water and
oxygen. The sodium chloride so produced is sent to the waste
treatment facilities.
At plant 144, the wastes emerging from chlor-alkali manufacture
are sent to a series of two settling ponds, with the exception of
those from the cell building, which are sent to a mercury
treatment unit first. The wastes from chlorine drying, fcrine
preparation, salt saturation and caustic loading are sent di-
rectly to the two settling ponds described above, where suspended
solids are removed and the pH adjusted prior to discharge. Two
emergency ponds are in parallel with these two ponds and wastes
can be diverted to them for special treatment if needed.
Mercury-containing wastes from the cell building are first
treated prior to being sent to the central waste treatment
system. The effectiveness of treatment based on six months of
data (129 days of measurements) is, in summary:
Mercury Concentration to
Secondary Treatment (mq/ll
Average
Maximum values
Minimum values
44.3
1920.0
0.48
Mercury Concentration
afte.r Treatment (mq/1)
0.43
15.0
0.01
Average Removal
Efficiency (percent)
99.0
83
-------
KCI WATER
K0ff
pH
KEC03 ADJUST
INLET BOX END BOX
VENT TO VENT TO
ATMOSPHERE NoOH SCRUBBER
ELKTROLYSiS AMALGAM
Cle TO LIQUIFACTION
DEPLETED BRINE TO SATURATION AND PURIFICATION
2K-Ho*2H20 >2KOH + 2Hg + H2
SLUDGE SALES
TO KOH
ABATEMENT
SYSTEM
OVERFLOW
TO
ABATEMENT
SYSTEM
• DEMORALIZED WATER
H2 TO USERS:
(I.) FUEL IN BOSLERHOUSE
(2.) OTHER PLANT USES
FIGURE 37
MERCURY CELL FLOW DIAGRAM (KOH) AT PLANT 130
-------
Paw Waste Loads from Mercury Cell Process
(All Amounts in kg/kkg of Chlorine)*
Purification
muds, CaCOjj
& Mg(OH)2
NaOH
NaCl
KCl
H2SO4
Chlorinated
Hydro-carbons**
Na2S04
C12
(as CaOCl2)
Filter aids
Mercury
Carbon,
graphite
CUSO4
Baged on 21 ._Facilltlgs
_Mean_ _Range
16,5 0.5-35
Plant 098 Plant130
o
7.25
o
_Mean_ Range
7.5 6.8-7.9
13.5
211
0
16
0.7
15.5
11
0.85
0.15
20.3
0.5-32
15-500
-
0-50
0-1.5
0-63
0-75
0-5
0.02-0,28
0.35-340
-
-
0
11.3
-
_
-
1.83
0.0018
-
-
40
50
0
-
_
-
_
-
-
-
35-U5
45-54
-
-
—
-
_
-
-
o.oo a
*can be converted to Ib/ton of product by multiplication by 2.0.
**depends markedly on grade of chlorine produced.
85
-------
Approximately 99 percent removal of mercury is achieved with the
mercury losses from the facility being kept tc about 0.0045-
0.0237 kg/day (0.0^-0.05 Ib/day) for the most part. Figure 38
gives a histogram of the mercury discharges on a daily total
quantity basis. The-mean value of this discharge parameter is
0.0178 kg/day (0.03882 Ib/day) or 0.000070 kg/kkg of chlorine
(0.000140 Ib/ton of chlorine). Ninety-one percent of the
measurements fell below 0.00014 kg/kkg.
At plant 098, several of the streams are completely recycled to
minimize trine wastes. Treatment of mercury-containing streams
makes use of sodium sulfide to precipitate mercury and mercury
sulfides. These materials are filtered from the streams,
recovered as solids and treated with sodium hypochlorite to
recover mercury (as chloride). The leached solids can then be
safely discarded and the mercury chloride-containing solutions
can be used for brine makeup and returned to the cells where the
mercury chloride is decomposed to elemental mercury for reuse.
The mercury effluent and
plant 098 are as follows:
chlorine treatment effectiveness at
Method
Mercury Recovery Unit
Chlorine
Neutralization System
Hydrogen Peroxide
Treatment of •
liquid effluent
Qualitative
Excellent
Excellent
Good
Waste Reduction
Accomplished
97 percent recovery of mercury
100 percent removal of chlorine
from waste gas stream
100 percent removal of available
chlorine
*As rated by plant personnel.
The mercury discharged and recovered from the sulfide treatment
system over a two month period in 1972 from this plant averaged
0.0108 kg/day (0.0237 Ib/day) or 0.000069 kg/kkg (0.000138
It/ton) of chlorine. Analysis of the data for the two month
period showed that the average mercury recovery was 256 kg/day
(568 Ib/day) or 7.5 kg/kkg (15.0,Ib/ton) of chlorine. At the
plant 130 mercury cell facility, brine filter sludges, potassium
hydroxide recovery wastes and other waste streams are fed into a
common treatment system, wherein the wastes are treated with
sodium hydrosulfide and flocculants. The insoluble mercury
products from treatment are removed by settling and filtration
and the wastes ar£ then discharged. The mercury content of the
86
-------
o.ot
0.02 0.03
MERCURY DISCHARGE (KG PER DAY)
0.04
0.05
RGURE 3©
HISTOGRAM OF MERCURY DISCHARGES FROM PLANT 144
-------
wastes is recovered by distillation from the recovered
The mercury treatment system is shown in Figure 39.
sludges.
Table 6 summarizes the mercury effluents from plant 130 as a
result of treatment over a one-year period. The mean mercury
effluent level of 0.0073 kg/day (0.016 Ib/day) corresponds to a
value of 0.000057 kg/kkg (0.000114 Ib/ton) of chlorine, similar
to the 0.000069 kg/kkg (0.000138 Ib/ton) calculated for the 098
plant and the 0.000070 kg/kkg (0.000140 Ib/ton) for the 1U4
mercury cell plant.
The general characteristics of the 098 plant discharge are listed
below. The seawater cooling water stream is mixed with the pro-
cess water effluent prior to discharge, hence the high TDS:
Total suspended Solids, mg/1
Total Dissolved Solids, mg/1
pH
Temperature, °C (°F)
Hydrogen Peroxide, mg/1
Sodium Sulfide, mg/1
Free Chlorine, mg/1
Mercury, mmg/1
Aver acre Range
5 5-10
20,000-25,000 (seawater)
7.1 6.7-8.5
12 (54) 10-19 (50-66)
0 0-1.0
0 0-0,5
Max. 0.08
Max. 8.0
Tables 7 and 8 give the plant 130 effluent stream data and
verification data. Tables 9 and 10 give the plant 144 intake and
effluent streams data with verification data.
b) Diaphragm cell process
The plant 057 facility described in this section is part of an
integrated complex using a considerable amount of recycling and
reuse technology.
sodium chloride brines are first purified by addition of sodium
carbonate, flocculating agents and sodium hydroxide in the
amounts required to precipitate all the magnesium and calcium
contents of the brine. The brine is then filtered to remove the
precipitated materials and electrolyzed in a diaphragm cell.
Chlorine, formed at one electrode, is collected, cooled, dried
with sulfuric acid, then purified, compressed, liquified and
shipped. At the other electrode, sodium hydroxide is formed and
hydrogen is liberated. The hydrogen is cooled, purified,
compressed and sold. The sodium hydroxide formed, along with
unreacted brine, is evaporated to 50 percent concentration.
During the partial evaporation, most of the unreacted sodium
chloride precipitates from the solution, which is then filtered.
The collected sodium chloride is recycled to the process, and the
sodium hydroxide solutions are further evaporated to yield solid
products.
88
-------
BRINE
FILTER
SLUDGE
ACID SULF1DE
V
RLTER
FEED
TANK
s
FILTER
PRESS
3
RLTRATE
HOLD
TANK
t
V
DRUMS p— .— — |
LAB
AU&I VCIQ
^ S
CO
AREA 3 OUTFALL
KOH
FILTER
SLUDGE
CELL ROOM
WASHINGS,
H? CONDENSATE,
»Q CLEANUP
OPERATION.
DECHLORINATED
BRINE
CONDENSATE, ETC.
->
S
r^
FEED ^
TANK ^
/
DRUMS
TREATERS
1
L ADJUST TO pH 7
2. ADD SULFIDE
3. ADD FLOCCULANT
4. SETTLE I ""
5. DECANT oninfar
1 ^ ^riiP? ^ SLUDGE
" TANK " TREATER "
U
ANAL
A
"I
IB
YSIS
A.
VACUUM
FILTER
V
s
'
w
.RECOVERED
MERCURY
HgS RECOVERY
FIGURE 39
MERCURY ABATEMENT SYSTEM AT PLANT 130
-------
TABLE 6. Monthly Mercury Abatement System Discharge
During 1972 at Plant 130
Average
Volume
Discharge
Month cu m(gal) /day
*V*^_^^_«H .^—•^ ^^^^.JMH^^^^BM^^H^B
Jan 144 (37,916)
Feb 118 (31,030)
Mar 92 (24,195)
Apr 112 (29,616)
May 115 (30,339)
Jun 134 (35,277)
Jul 124 (32,709)
Aug 137 (36,169)
Sep 131 (34,435)
Oct 129 (34,024)
Nov 126 (33,339)
Dec 118 (31,135)
Av. 123 (32,516)
Total Hg
Discharge
Average
Daily Hg
Discharge
0.369
0.327
0.198
0.184
0.318
0.214
0.225
0.302
0.127
0.133
0.176
0.144
(0.813)
(0.719)
(0.435)
(0.404)
(0.700)
(0.471)
(0.494)
(0. 665)
(0.280)
(0.293)
(0.377)
(0.251)
012 (0.
Oil (0,
,0064(0.
0059(0,
010 (0
0068(0,
0073(0,
0096 (0,
0041 (0,
0041 (0
0055 (0,
0.0036(0
026)
024)
014)
013)
023)
015)
016)
021)
009)
009)
012)
008)
0.224 (0.492) 0.0073(0.016)
Average
meg/I
__Hg
82
92
69
53
91
51
59
72
31
33
43
31
59
Statistical Summary: Mercury Abatement System Jan-Aug 1972 -
Total of 244 Days
Daily Mercury
Discharge,
Mean
Range, Max.
Standard Deviation
90% of Values
0.0086 (0.019)
0.0545 (0.120)
0.0077 (0.017)
0.0182 (0.040)
Daily Volume
Discharge,
cu m fgali/day
122 (32,164)
292 (63,945)
40 (10,492)
173 (45,594)
90
-------
TABLE 7. Plant 130 Effluent Data*
Outfall
_.ttl .
9,460(2,5)
5
8-11
Outfall
#2 _
Outfall
#3**
Intake
13,300(3.5) 42,400(11.2)
Flow, cu in/day
(MGD)
Total Suspended
Solids
pH 8-11 8-9 8-9
Color (APHA Units)
conductivity, umhos
Hardness, (Total)
(CaCO3)
Chloride
Free Chlorine
Fluoride
Phosphates (as P)
Nitrate (as N)
Iron
Copper
Chromium
Manganese -
Vanadium -
Arsenic - - - 0.28
Mercury, mcg/1 - - 1.2 1
Lead - - 0.1 0.1
sulfate - - 39 18
Turbidity - - - 16
. *Data~supplied by Plant 130, mg/1 unless otherwise specified.
**Main outfall, outfalls 1 & 2 feed into 3. This waste stream
contains potassium carbonate manufacturing effluent also.
-
-
uoo
1252
0
1
-
1.92
1.2
- -
.01
5
287
134
22
0
1
0.1
1.92
1.0
0*01
1 0.01
91
-------
TABLE 8. Measurements of the Effluents
From Plant 130
Parameter*
Flow, cu m/day
(MGD)
Temp., °C
Color, Apparent,
APHA Units
Turbidity, FTU
Conductivity,
mhos/cm
Suspended Solids,
PH
Alkalinity (Total)
P (CaC03)
T (CaCO3)
Hardness, (Total)
(CaCO3) mg/1
Calcium (CaCCO)
Chlorine
Chloride
Fluoride
Sulfate
Phosphates (Tota1)
Nitrogen (Total)
Iron
Dissolved oxygen
Mercuryr mcg/1
Hg cell
River Chlorine Major
(Ia£§fc§) J4sU£facti0n** Abatgmept** Out£ali**
8,540(2,25) 16,700(4.28) 42,000(11-1)
Not
Measured
2.0
60
23
230
70
7.8
0
97
145
115
0
35
0
45
0.38
1.55
0.19
***
5
11.95
60
19
240
210
11.9
40
180
60
25
0.2
47.5
0
44
0.4
0.45
0.5
8.3
5
0
10.1
180
55
320
75
9.4
30
135
140
110
.3
60
0
41
0.42
0.13
0.7
7.6
5
8.5
150
50
370
210
10.5
25
200
65
35
0
48.5
0
40
0.37
0.38
0.4
8.5
*mg/l unless otherwise specified.
**Corresponds to outfalls #1, 2 and 3 respectively on Table 21.
***Unable to determine at temperature below 5°C.
92
-------
TABLE 9. Plant 144 Intake Water
Parameter*
Temperature, °C
Color, Apparent, APHA Units
Turbidity, FTU
Conductivity, mhos/cm
Suspended Solids
Dissolved Solids
pH
Acidity: Total
Free
Alkalinity (Total) P
T
Hardness; Total
Calcium
Halogens: Chlorine
Chloride
Fluoride
Sulfate
Phosphates (Tota1)
Heavy Metals: Iron
Chromate (Cr + 6)
Oxygen (Dissolved)
COD
Plant Data**
8-24
75
10
65
6.6
15
GTC
Measurement
19
175
50
55
10
0
0
0
16
15
5
6.7
CaCO3
it
n
it
it
n
0,18
15
0.1
8
0.34
0.48
0.02
12
10
*mg/l unless otherwise specified.
**Data from corps of Engineers permit application, approximately
two years prior to verification sampling.
93
-------
TABLE 10- Plant 144 Effluent Data
Parameter*
Flow, cu m/day (MGD)
Temperature, °C
Color, Apparent, APHA Units
Turbidity, FTU
Conductivity, mhos/cm
Suspended Solids
Dissolved Solids
pH
Acidity: Total
Free
Alkalinity (Total) P
T
Hardness:fTotal
Calcium
Halogens: Chlorine
Chloride
Fluoride
Sulfate
Phosphates (Total)
Heavy Metals: iron
Chromate (Cr+6)
Oxygen (Dissolved)
COD'
Mercury, mcg/1
plant_Datg**
5,300 (1,9)
32-38
1,525
0
1,455
7.0
60
Verification
Measurement
8,360 (3-0)
33
30
10
2,000
0
1,777
7.5
0 C3CO3
0 »
0 "
14 «
20 »
10 «
0
1020
0.5
107
0.18
0.42
0.02
10
5
5
*mg/l unless otherwise specified.
**Data from Corps of Engineers permit application, approximately
two years prior to verification sampling.
94
-------
Figure 40 shows the flow diagram of a ,1810 kkg/day (2000 ton/day)
chlorine-caustic soda plant. A new 2080 kkg/day (2300 ton/day)
chlorine-caustic soda plant also exists in this facility. The
sodium hydroxide product from these two plants is concentrated in
another portion of plant 057. This function is illustrated in
Figure 41. All three of these facilities (all parts of plant
057) will be discussed below.
There are no brine wastes from plant 057 and several of the other
waste streams are diverted for other uses in the complex. This
stream diversion and maximal raw material utilization has served
to minimize the wastes to be treated. The raw wastes from the
newer plant are:
Waste Product
1. NaOCl
2. NaHC03
3. Chlorinated
Organics
4. Brine Sludge
5. Spent Sulfuric
Acid
6. Chromates
7. Suspended Solids
Process source Aye. .kgr/kkcr (Ib/tonL of..C12
Gas Scrubber
Gas Scrubber
Liquefaction
1.13 (2.26)
(Startup and shutdown)
2.49 (4.58)
(Wastes are ponded for recycle)
0.35 (0,70)
Brine Treatment
Chlorine Drying
Cooling Tower
Cooling Tower
The raw wastes from the old plant are:
Haste Product
1. Weak Caustic
2. Spent Sulfuric
Acid
3. NaOCl
4. Carbonate Sludge
(CaCO3)
5. Chlorinated
Hydrocarbons
Process .Source
Cells
Chlorine Drying
Tail Gas Scrubber
Brine Treating
10.5 (21)
1.0 (2.0)
0.000363 (0.000726)
0.0333 (0.0666)
Average kg/kkg of
Chlorine .jib/ton)
66.25, (12.5)
4.05 (8.1)
7.50 (15.0)
12.25 (24.5)
Chlorine Purification 0.70 (1.4)
The raw wastes from the caustic plant are;
waste Products
1. NaOH
2. Nad
3. NaOH
4. NaCl
Process Source
Entrainment
Entrainment
Filter Wash
Filter Wash
Average kg/kkg of
Product (Ib/ton)
4.4 (8.8)
5.1 (10.2)
17.6 (35.2)
20.3 (40.6)
95
-------
RIVER WATER
BRINE WELL-
NaCI
NaOH
RIVER WATER
COOLER
I
Hg DISTRIE
H2
(BUTTON
AMMONIA PUNT
H2S04-
RIVER WATER
SEA WATER
No CIO
TAIL GAS
SCRUBBER
3ATURATOR
_v
MIXER
CLAR1FIER
SETTLING PONDS
CELLS
COOLER
DRYER
COMPRESSOR
INTERCOOLER
-TAIL GAS
_V
NOTE;
• WASTE STREAMS
SOLIDS (LANDFILL)
•TRENCH NaOH STARTUP
AND SHUTDOWN
'NaOH STORAGE
AND DISTRIBUTION
RIVER WATER AND SEA WATER
'CHLORINATED WATER
£ STORAGE DISTRIBUTION
* 60% H2S04
WATER
—5? SEA WATER
LIQUEFACTfON
TANK CAR
LOADING
LIQUID CHLORINE
COOLING SEA WATER
CHLORINATED HYDROCARBONS
DISTRIBUTION
STORAGE
EVAPORATOR
FIGURE
DIAPHRAGM CELL CHLOR-ALKALI PROCESS
AT PLANT 057
96
-------
NoOH
FROM CELLS
\
f
EVAPORATORS
X
s
FILTERS
•s
>
COOLING
EQUIPMENT
x
s
FILTERS
"S
S
PURIFIERS
WASTE
ENTRAINMENT
I I
OTHER SLURRY
PLANT TO BRWE
USE TREATING
SYSTEM
SALT
TO
RECOVERY
PRODUCT
FIGURE 41
SODIUM HYDROXIDE CONCENTRATION FACILITY AT PLANT 057
-------
Many of the chlor-alkali waste streams, including brine wastes,
are either recycled or put to use elsewhere in the complex. This
section discusses treatment of those streams which are
discharged.
The newer chlor-alkali plant takes in 2,720 cu m/day (0.72 mgd)
of river water for cooling makeup and process water, as well as
54 cu m/day (0.0144 mgd) of well water for potable use. About
98.5 percent of the total cooling water flow of 109,000 cu m/day
(28.8 mgd) is recycled, and 90 percent of the process water flow
of 6040 cu m/day (1.6 mgd) is recycled. Of the potable water in-
take, 10 percent is recycled.
The waste treatment within this newer plant is:
Flow, I/day Treatment
Final
Stream N. Source
I/Gas Scrubber
2/Spent Sulfuric
Acid
3/Chlorine lique-
faction
4/Erine Treating
5/Cooling Tower
Blowdcwn
Method
409,000 Sunlight decompo-
(108,000) sition of NaOCl
2,890
(765)
492
(130)
327,000
(86,400)
75,700
(20,000)
Other plant use
Incineration
Solids to land-
fill
None
To plant
waste water
system
Used
Brine recycled
To plant
waste water
system
Waste chlorine in the tail gas is reduced by 80 percent in an
absorption process, and the remaining chlorine is removed by
scrubbing. These two processes are used in • series to attain
complete removal of chlorine from the tail gas.
Future treatment plans are:
Method
Chlorinated hydrocarbon
waste burner
Catalytic conversion
of scrubber effluent
to remove sodium
hypochlorite
Neutralization of
scrubber effluent
to remove sodium
carbonate
Estimated
Installation
^. ... Time
2 years
1 year
1 year
Estimated
Performance
100 percent
100 percent
100 percent
98
-------
mgd) , which
compression
atsorption.
newer plant.
At the older chlor-alkali facility in plant 057, river water
intake is 10,450 cu m/day (2.76 mgd) and seawater intake is
57,200 cu m/day (15.14 mgd). The cooling water flow is 61,000 cu
m/day (16.13 mgd), which is all non-contact except for the water
chlorination step. Process water flow is 6.530 cu m/day (1.726
is mainly as' brine. Other process .water uses are
cooling, hydrogen cooling, chlorine cooling and
There is less recycling of water here than in the
The effluent stream which is not recycled arises
from the tail gas scrubber, which has a flow of 133,000 I/day
(35,000 gal/day) or 141 l/kXg,(37.2 gal/ton) based on chlorine
product. This is disposed of completely in the plant waste
system. It contains sodium hypochlorite. The disposal of this
material will be eliminated and the tail gas will be used to
manufacture hydrochloric acid product, thus eliminating a waste
stream. When this happens, the older process should be close to
a nondischarge system.
The water intake to the caustic plant is:
cu in/day .ftngd)
river water
seawater
well water
1,890 (0.50)
90,900 (24.0)
57 (0.015)
The river water is treated; the well water is not.
plant water flows are:
The in-
Forced Draft Cooling
Process
Washdowns
Entrainment seawater
cu.m/day {mgd)
6,540 (1.73)
1,300 (0.344)
265 (0.070)
90,900 (24.0)
% Recycled
95
0
0
0
The only effluent to be treated is 4.4 kg/kkg (8.8 Ib/ton) of
sodium hydroxide and 5.1 kg/kkg (10.2 Ib/ton) of sodium chloride
in a 90,900 cu m/day seawater waste stream (the entrained
system).. This system is presently discharged without treatment.
Future plans call for it to be neutralized prior to discharge.
Chloride values entrained in this stream are considered to te too
low to be worthwhile for other plant usage. These three
facilities are being improved to further reduce discharges.
The effluents from the newer chlor-alkali facility, the
facility and the sodium hydroxide plant are shown below.
older
99
-------
Newer Plant:
Parameter
Total Dissolved
Sclids
Total Suspended
Solids
ECt
CCD
PH
Temperature, °C
Chromate
Older Plant:
Dissolved Solids
Alkali_Plant:
NaOH
NaCl
Hydrochloric Acid
Average Concentration, mg/1
Stream No. 1 2 3_ 4
18,330
(mostly
chlorides)
ia
o
o
7.8
38
1200
820
22r500 256
Ambient
0
0
~
31
-
0
0
11.0
Ambient
-
0
0
7.0
32
10
103,090 (chlorides, hypochlorites)
25
28.9 (added to seawater)
Hydrochloric acid is manufactured principally by two processes:
(1) As a by-product of organic chlorinations; and (2) By direct
reaction of chlorine with hydrogen. Only production by direct
reaction of chlorine is considered herein. In this process,
hydrogen and chlorine are reacted in a vertical burner. The
hydrogen chloride formed is condensed in an absorber from which
it flows to a storage unit for collection and sale. The ar-
rangement used at the exemplary facility (plant 121) is similar
to the standard flow diagram shown in Section IV. The special
waste treatment system used during startup of this facility
startup is shown in Figure 42.
The raw waste loads from hydrochloric acid manufacture are pre-
sented below. Some of these are markedly dependent on condi-
tions, with most of the wastes being produced during startups.
There are no water-borne wastes during periods of normal
operation.
Waste Products
1. Chlorine*
2. HC1**
Process source
Burner Run -
Chlorine-rich
Amount of _Prodiict
Startup - 100 kg/kkg(200 lb/
ton) avg. 5-200 range(10-400)
Operation - 5 kg/kkg(10 lb/
ton) avg. 0-10 range(0-20)
Shutdown - no waste
Startup - 4.5 kg/day (9 Ib/ton)
Operation - none
Shutdown - none
TOO
-------
STARTUP-
WASTE
NflOH * WATER VENT
t
>
SCRUBBER
WATER
ABSORBER
v
o
NaOH* WATER
l-<
NEUTRALIZATION
VESSEL
V
EFFLUENT
UJ
o
CO
a
P
<5
9
RGURE 42
STARTUP WASTE TREATMENT SYSTEM
AT PLANT 121
101
-------
NaOH***
reaction
products
(NaCl and
NaOCl)
Neutralization
Startup - depends on HCl
and C12 to be neutralized
Operation - none
Shutdown - none
*Emerges in vent gas during normal operation, neutralized
during startup by NaOH.
**A11 neutralized during startup.
***Caustic (NaOH) used has 12 percent Nad present and is cell
liquor from chlorine plant also in the complex.
All waste water treatment is performed during startup of the fa-
cility. During normal operation, there are no water-borne wastes
to be treated. Water use at the facility is listed below:
A- Input
Type
Lake
Hell
Quantity
cu in/day j./kkq
5,680 15,650
(150,000 (3,750 gal/
gpd) ton)
1,135
(30,000
gpd)
3,130
(750 gal/ton)
Comments on Content
TDS-300 mg/1, SS-10 mg/1,
Cl-65 mg/1, SO4-34 mg/1,
CaCO3-200 mg/1, Ca(HCO3)2-
2-250 mg/1.
Same as lake water except
lower in sulfate, low SS
(less than 10 mg/1).
B. Water Use
Type
Cooling*
Process
Disposal
from neut-
ralization
tank**
Miscellan-
eous
cu m/day j./kkg
1,135 3,130
(30,000 (750 gal/ton)
gpd)
760 2,085
(20,000 (500 gal/ton)
12,520
(120,000 (300 gal/ton)
380 1,040
(10,000 (250 gal/ton)
o
(Leaves as part
of product)
*Phosphate treatment used for this water. About 0.5 mg/1
excess phosphate is employed.
102
-------
**For safety purposes, continuous water flow is maintained
into the neutralization tank even during normal process
operation when no effluent or NaOH are introduced.
The effluents from the process streams before sewer at plant 121
are listed telow.
Waste Stream
1. Neutralizing
Reactor
2. Neutralizing
Siphon Tank*
3. Test Sink and
Washdown
4. cooling Water 1,135 (30,000 gpd)
cu m/day
4,355 (115,000 gpd) 12,00.0 (2,875 gal/ton)
520 (125 gal/ton)
1,040 (250 gal/ton)
3,130 (750 gal/ton)
190 (5,000 gpd)
380 (10,000 gpd)
*Siphon Tank is 26,500 1 and has less than 4 I/day drainage. It
is operated batchwise with excess caustic always present. When
the alkali content has been neutralized, it is disposed of.
After treatment, these streams are fed to a common equalization
pond for pH adjustment and suspended solids removal prior to
discharge. Effluent after this treatment (for the total complex)
contains less than 10 mg/1 of suspended solids and 2588 mg/1
chlorides and sulfates, mostly from other processes.
The plant effluent characteristics are given below. There are no
wastes during normal operation. All of the wastes arise from
startup operations. In addition, there is an air-borne chlorine
vent gas waste as noted earlier.
Parameter
Total
Suspended
Solids
Total
Dissolved
Solids
BCD
CCD
pH
Stream No. 1 Stream No. 2
Operation/Startup Operation/Startup
Stream
No. 3 No. 4
10*mg/l 10 mg/1 No
Effluent
300*mg/l 40,000-
50,000
** 10 mg/1
*# **
6.5-10.0 6.5-10.0
9 avg. 9 avg.
Batch
for a
number
of pro-
cesses;
90-180 kg
of C12 neu-
tralized per
month and
disposed of
in this
stream
Same as lake
water
*Same as lake water
**Undetectable
103
-------
All of the chlorine-burning HC1 plants are located within chlor-
alkali complexes. At present, there are four such facilities.
The 121 plant was sampled because of two considerations: 1)
Unlike the other facilities, hydrochloric acid wastes are easily
segregable. At other plants these wastes are mixed with chlor-
alkali wastes before treatment; and 2) Unlike some other
facilities, there are no hydrochloric acid wastes during normal
operations.
This facility could be further improved by: (1) More efficient
scrubbing of process tail gases to remove chlorine and use of the
resulting chloride/hydrochloric solutions elsewhere in the
facility; and (2) Reuse of the sodium chloride formed by acid
neutralization.
Hydrofluoric Acid
Hydrofluoric acid is manufactured by reaction of sulfuric acid
with fluorspar ore (mainly calcium fluoride). The reaction
mixture is heated and the hydrofluoric acid leaves the furnace as
a gas, which is cooled, condensed and sent to a purification
unit. There the crude hydrofluoric acid is redistilled and
either absorbed in water to yield aqueous hydrofluoric acid or
compressed and bottled for sale as anhydrous hydrofluoric acid.
At an exemplary plant (plant 152), the calcium sulfate byproduct
from the reactor is slurried with water and sent to waste
treatment. Also, all tail gases are scrubbed and the scrubber
water is sent to the waste abatement system. Figure U3 shows a
detailed process diagram for the exemplary facility, and Figure
4a shows the waste water recycling system in use at this plant.
The waste products from hydrofluoric acid manufacture are shown
below. Wastes consist of materials from the furnaces, which
include calcium sulfate, calcium fluoride and sulfuric acid, plus
fluoride-containing scrubber wastes.
104
-------
FLUORSPAR
GAS FUEL
AND AIR
THREE
FURNACES
IN
PARALLEL
COOLING WATER
RESIDUE
CoSO^TO
TRENCH AND
RECYCLE
RIVER COOLING
WATER INTAKE
TO RESCUE
TRENCH
AND PONDS
CONDENSER
DISTILLATION
COLUMN
TO PURE
PRODUCT
STORAGE
-COOLING
TO
SEWER
FIGURE 43
HYDROFLUORIC ACID PROCESS FLOW DIAGRAM OF PLANT 152
-------
SETTLING
POND
SETTLING
POND
CLEAR
WATER
POND
RECYCLE
WATER
PUMP
NEUTRALIZED RESIDUE SLURRY
NEUTRALIZING
PIT
FIGURE 44-
EFFLUENT RECYCLE SYSTEM AT PLANT 152
-------
Waste Product
Product „
Process Source
Avg. kg/kkg (It/ten) of
i. CaSOU
2. H2S04
3. CaF£
4. HF
5. H2SiP6
6. SiO2
7. S02~
8. HF~
Kiln (reactor)
Kiln (reactor)
Kiln (reactor)
Kiln (reactor)
Scrubber
Kiln (reactor)
Scrubber
Scrubber
3,620 (7,240)
110 (220)
63 (126)
1.5 (3)
12.5 (25)
12.5 (25)
5 (10)
1 (2)
The water use within plant 152 is shown below.
____ Total Quantity ____
cu m/davfqpdl 1/kkq feral/ton) "
Cooling 3,270 (864, 000) 90, 140 (21,600)
(river water)
Slurry and 3,270(864,000) 90,140(21,600)
Scrubber
0 percent
100 percent
All process and scrubber waste waters are recycled in the
exemplary plant. The waters used to slurry and remove the
calcium sulfate from the furnaces and scrubber waters are fed to
a pond system after being treated with caustic or soda ash and
lime to precipitate fluorides and adjust the pH. In the pond
system, the insolubles are settled out and the waters are then
reused in the process as shown in Figure 44.
Only cooling water is discharged from this facility. Table 11
shows the compositions of process waters before and after
neutralization and of the river intake water which is essentially
the same as the cooling water effluent. Low fluoride levels are
easily maintained because of segregation of discharged cooling
waters from the process water.
Verification measurements, shown for the plant intake water and
the outflow of cooling water, are given in Table 12. The
similarity of the intake and cooling water discharge verifies
that there is no process water leakage into the cooling stream,
and, therefore, there is no process water discharge from this
exemplary hydrofluoric acid manufacturing plant.
Hydrogen Peroxide
Hydrogen peroxide is manufactured by three different processes:
(1) An electrolytic process; (2) An organic process involving the
oxidation and reduction of anthraguinone; and (3) A by-product of
acetone manufacture from isopropyl alcohol, in this study, only
the first two processes were considered.
107
-------
TABLE ll.
Parameters
Intake Water and Raw Waste Composition Data
at Plant 152*
Units
"9/1
n
mg/1
og/l
mg/1
Aluminum Al
Beryl 1i urn Be
Calcium Ca
Cadmium Cd
Cobalt Co
Chromium Cr
Copper Cu
Iron Fe
Magnesium Mg
Manganese Mn
Molybdenum Mo "
Nickel Ni • "
Lead Pb
Ti tanium Ti "
Zinc Zn "
Barium Ba "
Potassium K mg/1
Sodium Na "
Tin Sn -ug/1
Ammonia-Nitrogen ' mg/1 N
COD " 02
Fluoride " F
Total Suspd Solids "
Total Solids "
Total Vol. Solids
Total Dissolved "
Solids
Nitrate mg/1 N
Nitrite "
Nitrogen-Kjeldahl "
Phosphate Total mg/1 P
Sulfate mg/1 S
Arsenic /^g/1
pH
TOC mg/1
*Data furmsned by manufacturer
Raw Waste
Into
Treatment
7400
66
640
16
300
46
44
3100
6.0
100
56
80
1320
240
1100
740
6.4
490
140
0,23
13.4
13.0
16596
22015
1220
4250
0.26
0.02
0.57
1.60
880
77
3.86
4
Recycle
Water From
Treatment
2200
64
450
12
280
22
28
780
6.4
106
56
. 68
3400
220
880
1020
8.6
660
140
0.05
-
12,5
59
3758
340
3572
0.20
0.01
0.46
0.96
767
49
7.22
6
Intake
River
Water
2600
20
12.2
2
26
4
4
1060
3.2
68
26
4
820
20
440
1280
0.6
4.2
24
0.23
_
0.2
21
124
58
132
0.13
0.20
0.46
0.02
7
74
7.17
5
108
-------
TABLE 12
Comparison of
Cooling Water
Plant
Discharge
Parameter
Flow
Temperature
Color (Apparent)
Turbidi ty
Conductivity
Suspended Solids
pH
Acidi ty: Total
Free .
Alkalinity (Total)
Hardness: Total
Halogens: Chlorine
Fluoride
Sulfate
Nitrogen (Total)
Heavy Metals:
Iron
Chromate (Cr+6)
Oxygen (Dissolved)
COD
Intake
Not Measured
Not
Measured
50
19
65
135
7
7
0
0
0
0
50
0
0
25
0
.40
.2
.20
0.25
0.02
11
25
intake Water
•ge at Plant
Di scharge
3,270
(864,000)
18 (64)
50
19
65
135
12
7.50
0
0
0
30
50
0
0.2
22
0.14
and
152*
Units
cu m/day
(6PD)
°C (°F)
Units APHA
FTU
mg/1 NaCl
mi cromhos/cm
mg/1
-
mg/1 CaC02
mg/1 CaC03
mg/1 CaC03
mg/1 CaCOj.
mg/1 CaC02
mg/1 C12
mg/1 F-~
mg/1 S04-2
mg/1 N
0.25 mg/1 Fe
0.02 mg/1 Cr*6
10.4 mg/1 Oj>
0 mg/1
'Data from verification sampling
109
-------
a) Organic process
In the organic process, anthraquinone (or an alkylanthraguinone)
in an organic solvent is catalytically hydrogenated to yield a
hydroanthraquinone. This material is then oxidized with oxygen
or air back to anthraquinone, with hydrogen peroxide being
produced as a by-product. The peroxide is water-extracted from
the reaction medium, and the organic solvent and anthraquinone
are recycled. The recovered peroxide is then purified and
shipped. Figure 45 shows a specific flowsheet for plant 069,
including part of the waste abatement program.
Vvaste Products
Sulfuric Acid
Trace organics
Hydrogen Peroxide
Operation Avg. Range
Ion Exchange Units
Contact Cooling
Purification Washings
12.5-15 (25-30)
0.17-0.35 (0.34-0.70)
20-25 (40-50)
The process runs continuously, except for shut-down approximately
10 days/year. Total discharge will normally be no higher during
start-up and shut-down periods than under operation at capacity.
well water at 312 cu m/kkg of product (74,500 gal/ton) having the
following composition in the water input at plant 069.
water Usage
Type
Cooling
process
Total solids
Carbon Dioxide
Total Hardness
Fe
Cu
Zn
Sulfate
Alkalinity (CaCO3)
cu m/kkq Jqa^/tpn)
365 (87,200)
110-125 mg/1
30-60 mg/1
80-100 mg/1
1-3 mg/1
0.03-0.06 m
-------
ORGANIC REACTION MEDIUM
ORGANIC
SOLVENT"
HYDROGEN-
\
f
HYDROGENATION
\
t
OXYGEN
W
OXIDATION
\
I
EXTRACTION
AND
PURIFICATION
SHIPPING
I
PRODUCT
WATER
TREATMENT
V
ORGANICS
H2S04
DITCH
FIGURE 45
HYDROGEN PEROXIDE PROCESS DIAGRAM FOR PLANT 069
-------
Haste stream
cu m/kkg
(qajyton)
Treatment
Final
Pisposaj.
Process Process 291 1. Peroxide reacted River
Effluent > <70,200) with iron filings
2. Skimmers used to
trap organics for
recovery
3. Haste sulfuric acid
is collected and
discharged at a
controlled rate
4. Solids (alumina &
carbon) are hauled
to landfill
The effectiveness cff the treatments in use is:
Qualitative
Method Rating _, f
Reduction Generally satisfactory
Skimming Generally satisfactory
Waste Reduction
Accomplished
80 percent reduction of per-
oxide to water and oxygen
60-70 percent of organics
recovered
The effluent composition after treatment is given in Table 13.
The wastes consist of unreacted peroxide and a small amount of
organics and sulfates.
fc) Electrolytic process
In the electrolytic process, a solution of ammonium bisulfate is
electrolyzed* Hydrogen is liberated at the cathodes of the cells
used, and ammonium persulfate is formed at the anode. The
persulfate is then hydrolyzed to yield ammonium bisulfate and
hydrogen peroxide which is separated from the solution by
fractionation. The ammonium bisulfate solution is then recycled,
and the peroxide is recovered for sale. The only waste is a
stream of condensate from the fractionation condenser. Figure 46
shows the process waste treatment system at plant 100.
Table 14 lists the raw wastes from peroxide manufacture at plant
100, These consist of ammonium bisulfate losses, ion exchange
losses, boiler blowdowns and some cyanide wastes from the special
batteries used in electrolysis.
Plant water intake and use are as follows:
112
-------
TABLE 13. Plant 069 Process Water Effluent After Treatment
Parameter*
Plant Data
Average Rani
Verification Sample
Suspended
Dissolved
Total
Total
BOD
COD
PH
Temperature
T.O.C.
Hydrogen Peroxide
Turbidity (Jackson
Units)
Color (APHA Units)
Acidity (Free)
Acidity (Total)
Alkalinity (Total)
Hardness (Total)
Chloride
Sulfate
Iron
Copper
Flow
Solids
Solids
40
30°C
25
25,000
cu m/day
(6.6 MGD)
15-20
310-330
6-7
6-9
5-15
60-80
20-20
40-50
150-195
90-105
40-75
2-3.5
.08-0.09
Verification
Measurement
9
98
50
6.4
27°C
12
50
61
92
5
43
1.6
26,000
cu m/day
(7.1 MGD)
Plant 069
Measurement
9
117
33
6.6
37.8
25
10
46
7
52
0.26
113
-------
WATER SUPPLY
DEEP WELLS
SLUDGE
SETTLING
TANK
SLUDGE
SETTLING
TANK
_y
COOLING WATER
FOR HEAT
EXCHANGERS
CONDENSERS
(INTERMITTENT DISCHARGE ONCE A WEEK)
WATER
DEIONIZERS
YELLOW
SOLUTION
DEIONIZER
REGENERAnON EFFLUENTS
(INTERMITTENT DISCHARGE)
_V
NK
TOTAL STREAM
BOILERS
CONTINOUS BOILER
BLOW-DOWN
FIGURE 46
SCHEMATIC SHOWING WASTE SOURCES AND DISCHARGE AT PLANT 100
-------
TABLE 14. Raw Waste Loads at Plant 100
Waste Process
Product Source
1. Blue prus- Purif.
siate sludge
kg/kkg of .Peroxide (ib/ton)
Operation Startup Shutdown
0.18(0.36)
2.
3.
a.
5.
6.
7.
8.
9.
Gray sludge
Ion Exchange
sludge
H2S04
(NHU) 2S04
Water flow
HC1
NaoH
Steam
condensate
Battery
rebuild
Deionizer
regen.
Plant solu~
tion loss
Plant solu-
tion loss
Cooling
Deionizer
regen.
Deionizer
regen.
Boiler
blowdown
(5 times
per year)
- —
0.0018(0.0036)
0.012(0.024)
2000-2900
(4000-58000)
1.3(2.6)
0.33(0.66)
581(1162)
No significant diff-
erence during start-
up S shutdown periods.
Plant runs contin-
uously; shuts down
once per year.
Comments
H^SOU. and (NH4)£SO4 are used to replenish plant solution.
Na4Fe(CN)6 is'converted to (NH4) 4Fe (CN) 6 through ion ex-
change (yellow solution) .
NH4SCN is oxidized in the batteries and is used for
better current efficiency.
HC1 and NaOH are used for regeneration of demine rali zed
water ion exchange resins.
115
-------
Water
Municipal
Well
Flow, cu m/day Amount, 1/kkg
(mod) (gal/ton)
«V^»^W*^*^B4fl*^H4»^«^»M^w»v »«^*»«^^™^fc^—^^*p«,^«^—^»»
7.2 (0.0019)
41,600 (11.0)
Use
601 (114) Drinking,
Washing,
Sanitary
3,480,000 76 cu m/day
(0.002 mgd)
demineralized
for process
water, rest
used as cooling
Of the 76 cu m/day of process water, 31 percent is used in the
product. Recycle flow of process water is 132 cu m/day and re-
cycle flow of steam is 305 cu m/day (liquid basis). About 26.5
cu m/day is boiler blowdown. None of the cooling water is
recycled. Table 15 lists the various plant effluent streams,
their sources, flows and treatments. Treatments consist of ion
exchange for pH control and recovery of some process materials,
and recovery of platinum in the waste streams. After this,
wastes are discharged.
Performance information on the pH control and ion exchange
technology used for waste abatement in this plant is:
Method
1. pH Control
2. Process change
3. Monitoring
Qualitative
Good
Excellent
Good
Waste Reduction
Accomplished
99+ percent
CN- load reduced 98 percent -
Additional concentration to
discharge stream less than
0.01 mg/1
Reduces unknown discharges
and allows quick operation
response.
Table 16 lists the compositions of the various effluent streams
after treatment. These streams are mixed prior to discharge.
Table 17 shows an analysis of the intake water and final effluent
after mixing. Only very small amounts of materials are
introduced into the waters used, and cyanides in the effluent are
negligible.
Nitric Acid
Nitric acid is manufactured from ammonia by a catalytic oxidation
process. Ammonia is first catalytically oxidized to nitric
oxide, which is then further oxidized to nitrogen dioxide. The
nitrogen dioxide is then reacted with water under pressure to
yield nitric acid. Plant 114 manufactures only commercial 63
116
-------
TABLE 15. Effluent Treatment Data for Plant 100
A. Water Streams
StreamNo.
Source
I/ day
(MGD1
1/kkg
1. Low Exchange
Regenerant
2. Blue Prussiate
Supernatant
(filter back-
wash)
3. yellow Solution Ion Exchange
4. Boiler Slowdown Boilers
B. Treatments
Demineralizer 3,790(1,000)
Filters 568(150)*
317(76)
47.6(11.4)
568(150)* 47.6(11.4)
26,500(7,000) 2,210(530)
Stream No.
(same as above)
Treatment Method
Final
Disposal
Plant effluent
Anion and cation regener-
ants are mixed to control
pH and slowly released.
Settled for platinum recov- Plant effluent
ery, siphoned and
filtered**.
Backwash recycled to pro- Plant effluent
cess and regenerant is
discharged.
Dilution Plant effluent
*These operations are batch carried out an average of once
per week.
**Sludges recovered here are sent to refiners for recovery
of platinum values.
117
-------
TABLE 160 Composition of Plant 100 Effluent Streams
After Treatment*
Constituents
Total Suspended
Solids
Total Dissolved
Solids
BOD
COD
pH
Temperature, °C
conductivity
micromhos/cm
Alkalinity
Free Cyanide
Phosphate
Chloride
No. 1
Stream
1856 as CaC03
equiv. during
regeneration
comparable to
raw water
Same as raw
water
Same as raw
water
6.5-8.5
17
7160
No. 2
Stream
No. 3
stream
18
7
18
<2
No. ;4
Stream
200-400 40,000 1,000
400
0
30
20-30 (as
Nad)
*all units mg/1 unless otherwise specified.
118
-------
TABLE I/. Plant 100 Water Intake and Final Effluent
Verification Measurements
Parameter*
-j
Conductivity,
micromhos/cm
Color
Turbidity
SS
PH
Sulphate
Nitrate
Phosphate
Iron
Chloride
Hardness (Ca)
Total Hardness
Well_Watgr
120 (as NaCl)
2UO
0
0
0
6.88
18
3.3
0.35
0.02
6.5
65
95
Qutfall
120 (as NaCl)
0
0
0
7.04
21
2.3
0.36
0-01
7.5
70
90
*mg/l unless otherwise specified.
119
-------
percent nitric acid. Fuming (i.e., more than 70 percent) nitric
acid and nitrogen pentoxide are made only at a few facilities and
are not covered in this report. The flow diagram for plant 114
is given in Figure 47.
The raw waste load from nitric acid production at Plant 114 is
listed below. The waste values are not affected by startup or
shutdown. There are no nitrates in the waste. All weak nitric
acid lost in the manufacturing process is recycled to the process
at this facility. The wastes consist only of water treatment
chemicals used for the cooling water.
Waste_.Product8
1. Lime
2. Calcium and
Magnesium
Carbonates
3. Disodium
Phosphate
4. Sodium Sulfate
5. Sulfuric Acid
6. Chlorine
Process Source Avg. kg/kkor HNO3(lfc/ton)
Boiler Feedwater
Boiler Feedwater
Boiler
Boiler
Cooling Tower
cooling water
Treatment
0.47 (0.94)
0.6 (1.2)
0.0016 (0.0032)
0.0008 (0.0016)
0.0016 (0.0032)
1.0 f2.0)
Plant water use is shown below and describes the large amount of
water and weak acid recycling at the plant. Only cooling water
is discharged, and this waste stream is currently untreated.
A. Water Inputs
Well
B. Water-Use
cooling
Process stream
3,815
(1,008,000 gpd)
13,150
(3,150 gal/ton)
Quantity
31,000
(8,000,000 gpd)
775
(200,000 gpd)
106,800
(25,000 gal/ton)
2,670
(6,250 gal/ton)
95
100
The plant effluent streams are shown below.
are only water treatment chemicals.
Wastes discharged
-------
AMMONIA
COOLING WATER
EVAPORATOR
_y
AIR
J/
COMPRESSOR
MIST ELIMINATOR
LOW PRESSURE
STEAM - —
CONDENSATE
TO TANK
_V
FILTER
SUPER HEATER
FILTER
_V
MIXER
\L
BURNER
TURBINE GAS HEATER
HIGH PRESSURE STEAM.
TO STEAM TURBINE
BURNER GAS BOILER
CATALYST
RECOVERY FILTER
TAIL GAS TO CATALYTIC
COMBUSTER, GAS EXMNDER.^-
TURBINE GAS BOILER ^^
AND VENT.
TAIL GAS HEATER
FEED WATER-
COOLING WATER,
COOLING WATER,
COOLING WATER^
FEED WATER HEATER
NITRIC GAS COOLER
WEAK ACID CONDENSER
ABSORPTION TOWER
NIT
BLEACH AIR COOLER
LOW
PRESSURE
STEAM
TAIL GAS PREHEATER
CONDENSATE TANK
PRODUCT NITRIC ACID
FIGURE 47
NITRIC ACID PROCESS FLOW DIAGRAM
FOR PLANT 114
121
-------
Sources
cu m/dav
l/kkg
Boiler Feedwater
Treatment
Boiler Elowdowns
Ccoling Water
Elowdowns
(1,250 gpd)
30
(7,800 gpd)
3600
(95,000 gpd)
16
(3.9 gal/ton)
85
(24.4 gal/ton)
1240
(297.0 gal/ton)
(All streams tie into common effluent header before discharge)
Because of recycling of some water and of all nitrogen-containing
streams, this plant is exemplary. However, as in many other
cases, cooling waters are untreated prior to discharge. The
plant effluents are listed below.
Total Suspended Solids
Total Dissolved Solids
EOD
CCD
pH
Temperature
Turbidity
Color
Conductivity
Alkalinity (Total)
Hardness (Total)
Chloride
Fluoride
Sulfite
Sulfate
Phosphates
Nitrate
Iron
Manganese
Average
80
239
5
10
7.8
25
125
330
500
300
300
18
0.2
0.2
60
0.4
0.2
7.5
0.2
Range
50-100
200-250
7.5-8.5
24-27
mg/1
mg/1
mg/1 (02)
mg/1 (02)
°C
JTU
PTCO
mhos
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
A plant visit verified that only cooling water is discharged from
plant 114.
Potassium Metal
For the commercial preparation of potassium metal (K), potassium
chloride is melted in a gas-fired melt pot and fed to an exchange
column. The molten potassium chloride flows down over steel
Raschig rings in the packed column, where it is contacted by
ascending sodium vapors coming from a gas-fired reboiler. An
equilibrium is established between the two, yielding sodium
chloride and elemental potassium as the products. The sodium
chloride formed is continuously withdrawn at the base of the
122
-------
apparatus and is normally sold. The column operating conditions
may be varied to yield either pure potassium metal as an overhead
product or to vaporize sodium along with the potassium to produce
sodium potassium (NaK) alloys of varying compositions. Potassium
metal of over 99.5 percent purity can be continuously produced by
this process.
Production of potassium in the United States was about 90 kkg
(100 ton) in 1972, essentially all of it originating from one
facility - plant 045. Contacts with this manufacturer have
revealed that the process diagram accurately describes their
process. No process water is used and there are no waterborne
effluents.
Potassium Dichromate
Potassium dichromate is prepared by reaction of potassium chlor-
ide with sodium dichrcmate. Potassium chloride is added to the
dichromate solution, which is then pH-adjusted, saturated, fil-
tered and vacuum cooled to precipitate crystalline potassium
dichromate. The product is recovered by centrifugation, dried,
sized and packaged. The mother liquor from the product centri-
fuge is then concentrated to precipitate sodium chloride which is
removed as a solid waste from a salt centrifuge. The process
liquid is recycled back to the initial reaction tank.
The raw wastes from potassium dichromate manufacture are listed
below. These are crystalline sodium chloride and filter aids
which are solid wastes and are hauled away for landfill disposal
by a contractor.
Waste Products Process Source kg/kkg of Product (Ib/ton)
NaCl
Filter aid
Centrifuge
Filter
UOO (800)
0.85 (1.7)
Exemplary plant water usage is given below. All process waters
are recycled. The only wastes currently discharged emanate from
contamination of once-through cooling water used on the baro-
metric condensers on the product crystallizer. Plant 002 has
plans to replace the barometric condensers with heat exchangers
using non-contact cooling water. This should eliminate the
hexavalent chromium waste completely. With this change, no
process waste waters will be discharged.
123
-------
Water Inputs to plant
cu m/day
.Quantity.
comments
1/kkg
River
1,325
(350,000 gpd)
Municipal 245
(65,000 gpd)
B. water Usage
97,200 Untreated except for
(23,300 gal/ton) macrofiltration
18,100 Untreated
(4,330 gal/ton)
Quantity
cooling
Process
(makeup)
cu m/day
1,325
(350,000 gpd)
245
(65,000 gpd)
97,200
(23,300 gal/ton)
18,100
(4,330 gal/ton)
0
100
Presently, the only effluent from this plant is cooling water,
possibly contaminated with hexavalent chromium in the barometric
condenser. Replacement of the condenser with a non-contact heat
exchanger will eliminate cooling water contamination, although a
larger amount of water will have to be used for the less
efficient non-contact heat exchanger.
Potassium Sulfate
The bulk cf the potassium sulfate manufactured in the United
States is prepared by reaction of potassium chloride with
dissolved langbeinite ore (potassium sulfate-magnesium sulfate).
The langbeinite ore is mined and crushed and then dissolved in
water to which potassium chloride is added. Partial evaporation
of the solution produces selective precipitation of potassium
sulfate which is recovered by centrifugation or filtration from
the brine liquor, dried and gold. The remaining brine liquor is
either discharged to an evaporation pond, reused as process water
or evaporated to dryness to recover magnesium chloride. The fate
of the brine liquor is determined by the saleability of the
magnesium chloride by-product (depending on ore quality) and the
cost of water to the plant. A diagram for the process used at
plant 118 is given in Figure 48.
The table below presents a list of the raw wastes expected for
potassium sulfate manufacture:
124
-------
WATER
KCI
DISSOLVER
LANGBEINITE ORE
ro
en
FILTRATION
>WASTE MUDS
REACTOR
FILTRATION
WATER
VAPOR
PARTIAL
EVAPORATION
EVAPORATOR
PRODUCT
K^
CLARIFIER
BRINE LIQUOR FOR RE-USE
FIGURE 48
POTASSIUM SULFATE PROCESS DIAGRAM AT PLANT 118
-------
Waste Product
Process Source frg/kkg of Product (Ib/ton)
Average ~ Rancje
Dissolution of
langbeinite ore
Liquor remaining
after removal of
potassium sulfate
15-30
(30-60)
0-2000*
Muds,(silica, alumina,
clay and other
insolubles)
Brine liquor
(Saturated magnesium
chloride solution)
*Part of the magnesium chloride is recovered for sale and part
of the remaining brine solution is recycled for process water.
The high value corresponds to the case of no recycle or recovery
of magnesium chloride. These brines contain about 33 percent
solids. The wastes consist of muds from the ore dissolution and
waste magnesium chloride brines and are not affected by startup
or shutdown. The latter brine can sometimes be used for
magnesium chloride production if high grade langbeinite ore is
used. Composition of the brine solutions after potassium sulfate
recovery is:
Potassium
Sodium
Magnesium
Chloride
Sulfate
Water
3.2 percent
1*3 percent
5.7 percent
18.5 percent
U.9 percent
66.7 percent
The amount of brine produced is about 650 kg of solids/kkg of
potassium sulfate (1300 Ib/ton) after evaporation. For higher
grade ores, the sodium content is lower. The data presented
above were supplied by plant 118.
The muds listed above are separated from the brine solutions at
this exemplary plant by filtration after dissolution of the
langbeinite ore. These are recovered and disposed of as landfill
on the plant site. The brine wastes, containing mostly magnesium
chloride, are either disposed of or treated in three different
manners:
1. Evaporation with recovery of magnesium chloride for sale.
This is practiced only when high grade ores are processed.
2. Reuse of the brine solution in the process in place of using
process water. This is normally done to a considerable extent.
3. Disposal of the brines in evaporation pits.
At plant 118, all three of the above options are practiced,
depending on the quality of the ore being processed.
126
-------
Water use at plant 118 is described below:
Water Inputs;
Type
Quantity
cu m/day (mgdl 1/kkg (gal/ton)
Well Water 3,790 (1.0) 8,360 (2,000)
Water Purity
40 mg/1 total
solids
Water Flows:
.^ Quantity
cu m/day fmgd) 1/kkg (gal/ton)
Percent Recycled
Cooling
Process
13,600 (3.6)
2,270 (0.6)
30,000 (7,200)
5,010 (1,200)
60-70 percent (remainder
evaporated)
67 percent recycled, 33
percent lost either by
evaporation or re-
moval from system
with product or
by-product.
There are no effluent streams from the plant since much of the
water is recycled. Most of the water losses occur during the
process evaporation steps.
Sodium Bicarbonate
Sodium bicarbonate is manufactured by the reaction of soda ash
and carbon dioxide in solution. The product bicarbonate is
separated by thickening and centrifugation and is then dried,
purified and sold. A detailed process diagram for plant 166 is
given in Figure 49. This facility is located within a Solvay
process complex.
A listing of raw wastes produced in bicarbonate manufacture at
plant 166 is shown below. These consist of unreacted soda ash,
solid sodium bicarbonate, boiler wastes and ash from power
generation equipment. The ash is treated as a solid waste.
Waste product
1. Na2CO3
2. Ash
3. Water purif.
sludge
4. NaHCO3
Process Source
kg/kkg__of_Product (Ib/tonl
Average
Slurry thickener overflow
Power generation
Boiler feed water
purification
Slurry thickener overflow
38.0(76.0) 0-375(0-750)
17*9(35.8)
0.3(0.6) ,
10.0(20.0)
127
-------
RECYCLE LIQUOR
OVERFLOW
ro
CO
SOCA
ASH
SODA ASH
RECYCLE
LIQUOR
TANK
RECYCLE
LIQUOR
STORAGE
SOCA ASH
nssou/ER
DISSOLVED
SODA
LIQUOR
LIQUP
OVERFLOW
SCRUBBER
FLASH
DRYERS
(2)
CENTRIFUGES
(8)
PRODUCT
TO COOLER, CURER,
CLASSIFICATION
MUCING
TANK
SAND
FILTERS
(2)
FILTER
BACK. WASH
PRESSURE
LEAF
FILTER
CARBONATING
COLUMNS
(8)
SODIUM
SESQUICARBONATE
FEED
SEWER
SODUM
SESQUCARBONATE
PURGE
BACK WASH
(SODIUM
SUSQUICARBONATE
PURGE)
THICKENERS
(3)
SEWER
MILL
WVTER
FIGURE 49
SOLVAY SODIUM BICARBONATE PROCESS FLOW DIAGRAM AT PLANT 166
-------
The quantity of slurry thickener overflow depends upon the oper-
ation of another plant utilizing this by-product. The overflow
is not constant, and occurs only when the sister plant mentioned
above cannot absorb the entire flow. Consequently, the value
shewn above is based on an annual average, with a wide variation
in flow over the period.
The water usage at plant 166 is shown below. Most of it is used
for cooling purposes.
Water Inputs to Plant:
Type cu m/dav (mcrd)
Lake 1,430 (0.378)
Municipal 119 (0.0315)
1/kkg (gal/ton) Treatment.
5,430 (1,300) Chlorinated prior to
use as cooling water
455 (109)
Water.. Usage;
Cooling
Process
cu m/day fmqd)
1,430 (0.378)
119 (0.0315)
5,430 (1,300)
455 (109)
Recycled
None
variable
Treatments are carried out for the two emerging waste streams.
These streams are fed to settling ponds to remove suspended
solids and then discharged.
Stream
Settling
Pond Over-
flow
Cooling
Water
(Discharge)
1/kkcf (gal/ton^ 'Treatment Dig go sal
Slurry
thickener
Various
heat ex-
change
devices
found
throughout
plant
287 (69)
5,430 (1,300)
Settling
Pond
a)Containment
of wastes
b)Cooling water
segregation
c)Some water
recycling
<3) Collection
and sampling
of wastes
Plant
Effluent
Effluent
Individual effluents from this plant are combined with other
sewer effluents. Some wastes are treated in conjunction with
soda ash plant wastes. Tabulated loads are based on reasonable
allocations.
The effluent from plant 166 contains 20,000 mg/1 of dissolved
solids (mostly dissolved carbonates), amounting to 5.75 kg/kkg of
product (11.5 Ib/ton). All of the bicarbonate wastes are treated
129
-------
along with chlor-alkali and soda ash wastes at the 166 facility
in a common treatment system prior to discharge. There are no
net effluent loads to the cooling water based on average daily
operation. There are no organics in the plant effluent.
Plant 166 has plans to use the weak slurry thickener overflow,
which constitutes their present source of waste, as a source of
liquid for the product dryer scrubber and to recycle this liquid
(concentrated with respect to sodium carbonate) back to the
process. These process changes will eliminate the discharge of
process waste waters.
Verification measurements on the plant intake water, cooling
water, and effluent are given in Table 18. The similarity of
composition of plant intake and cooling water discharge verifies
segregation of cooling water from process water. The process
effluent measured is the effluent of the whole plant complex and
hence is not indicative of that of an isolated bicarbonate unit.
Sodium Carbonate
Soda ash is produced by mining and by the Solvay Process. In the
solvay Process sodium chloride brine is purified to remove
calcium and magnesium compounds. It is reacted with ammonia and
carbon dioxide produced from limestone calcination to yield crude
sodium bicarbonate which is recovered from the solutions by
filtration. The bicarbonate is calcined to yield soda ash. The
spent ammonia solution is reacted with slaked lime and distilled
to recover ammonia values for process recycle. The calcium
chloride formed as a by-product during the distillation is either
discharged as a waste or recovered by evaporation. Figure 50
shows a process flowsheet for the facility at plant 166.
Although all Solvay Process plants have high dissolved solids
effluents, this plant is unusual in that it recovers a
significant amount of an otherwise wasted by-product. Since the
market for calcium chloride will not absorb the by-product
generated from such recovery from all Solvay plants, this plant
cannot be considered to be exemplary on this basis.
The raw waste loads for the 166 facility consist of brine
purification muds, unreacted sodium chloride and the calcium
chloride by-product, as follows:
130
-------
TABLE 18. Plant 166 Verification Data
Parameter
Plant Intake
Measured Furnished
Bi carbonate
Cooling Water
Plant
Complex
Effluent
Flow,cu m/day Not meas- 188,000
(MGD) ured (49,5)*
Temperature, °C 11.2
Color (Apparent) 20
APHA Units
Turbidity, FTU 10 27
Conductivi ty,
mg/1 NaCl 2000
micromhos/cm 3800
Suspended Solids,
mg/1 5
Dissolved Solids,
mg/1
PH
Acidity:
Total ,mg/l CaC03
Free,mg/1 CaCO£T
Alkalinity (Total)
P,mg/l CaCOl
T,mg/l CaCOJ
Hardness:
Total ,mg/l CaCOS.
Calcium,mg/l CaCOJ,
Halogens:
Chlorine,mg/1
Chloride,mg/1
Fluoride,mg/1
Sulfate,mg/1
Phosphates
Total,mg/l
Nitrogen
Total, mg/1 N
Heavy Metals: Iron
mg/1 Fe
Chromate,mg/l Cr+6
Oxygen (Dissolved),
mg/1 0£
*Furnishes cool ing water to whole plant
Not Measured
Not Measured
270
30
1800
3400
160
17,400
(4.6)
Not Measured
275
0
67,000
118,000
206
2850
7.80
0
0
0
195 171
1300 1428
1250 571
0.1
1525
0.45
170
1 .1
0.55
0.07
0.01
4.7
2560
7.75
0
0
0
305
1000
950
1.9
1275
0.50
130
1.0
0.43
0
0
13
76,000
10.8
0
0
460
610
45,000
45,000
0
1 .36
640
0.7
1 .7
0.48
0
4
131
-------
CO
ro
FIGURE 50
SOLVAY SODA ASH PROCESS FLOW DIAGRAM AT PLANT 166
-------
Waste Products
Process Source kg/kkg of_Soda Ash (Ifa/ton)
1. CaCO3
2. Ka2C03
3. CaS03
4. NaCl"
5. CaC12
6. Na2S04
7. Fe(OH)*3
8. Mg(OH)2
9. CaO (inactive)
10. NaOH
11. siog
12. CaO (active)
13. NH3
14. H2S
15. Ash & Cinders
DSr B, P
B
DS
DS, B
DS
B
B
DSr B, P
DS, B
B
DS, B
DS
DS
DS
84.5
0.3
31
510,5
1090
0.8
0.1
48.5
109,5
0.05
58,5
24
0.15
0.02
40
(169)
(0.6)
(62)
(1021)
(2180)
(1.6)
(0.2)
(97)
(219)
(0.1)
(117)
(48)
(0.3)
(0.04)
(80)
DS = Distillation, B = Brine, P = Power
Water Inputs to plant:
Type l/kkg^ (gal/ton)
River 3,650 (875)
Lake 4,680 (1,120)
Municipal 2,030 (486)
Comments
Water Flows:
Cooling
Process
Sanitary
Boiler Feed
52,100 (12,500)
4.5 (1.1)
Est. 74-149
(18-36)
5,420 (1,300)
Sent to Power Section for
toiler feed water
Treated prior to use with
chlorine
Majority is sent to Power
Section for toiler feedwater
Recycled
0
The maximum process water use is atout 149 1/kkg
but the average is only 4.5 1/kkg (1.1 gal/ton).
(36 gal/ton),
Most of the water use is for cooling purposes and little stream
recycling is employed. Treatment methods in use are:
133
-------
Stream
Source
Treatment
Ccoling water
effluent
Various heat
exchangers
throughout
plant
Settling pond
effluent
Distiller
wastes
Disposal to
cooling water
sewer system
Discharge to
source of
cooling water
a. internal recycle
b. Segregation of
waste
c. collection and
containment of
wastes
Settling out sus-
pended solids with
coagulation and
precipitation of
metals and other
chemicals
Individual effluents from this plant are combined with other
effluents.
Treatment consists of use of settling ponds and some pH control
prior to discharge. The performance of this treatment is
detailed below:
ffethgd.
Evaporation of
distiller waste
Settling Ponds
Qualitative
Rating
Good
Excellent
Waste Reduction
Accomplished
Reduces Cad by 21 percent
NaCl by U percent
Suspended solids reduced
by 99 percent*
In addition, two other methods of treatment are used or planned:
(1) part of the wastes may be used for municipal waste
treatment.
(2) part of the raw distiller waste stream is diverted to
a small plant for calcium chloride recovery. About
21 percent of the calcium chloride in the raw waste is re-
covered on this sidestream.
The plant effluent after treatment contains about 100,000 mg/1
dissolved solids (mostly NaCl and CaCl2!) in the process waste
stream and is also fairly high in suspended solids. This type of
effluent is typical of a Solvay process plant.
Calcium Chloride Recovery
The flow diagram for the calcium chloride recovery process at
plant 166 is shown in Figure 51. The waste stream is first
cycled through a number of partial evaporation and filtration
steps to concentrate the waste solutions. After this, further
partial evaporation is used to selectively remove the sodium
chloride from solution and then total evaporation is used to
recover calcium chloride from the remaining solution.
134
-------
CL
NOTE;
* OCCURS DURINC
OPERATIONAL
UPSETS
CONDENSATE TO
MILL
WATER
1
BAR
PRIMARY
CENTRIFUGE
\
s
k
/
REPUDDLING TAN
\
/
SECONDARY
CENTRIFUGE
\
/
DRYER
ARIFIED LIQUOR >
HP STEAM ^
C02 ^
ci2 ^
LP STEAM >
BOILER HOUSE <
MILL WATER
TO SEWER
T
WEAK LIQUOR
STORAGE
\
/
CARBONATOR
\
/
1st ft 2nd EFFECT
EVAPORATORS
\
/
SECONDARY
SETTLERS
\
/
3rd EFFECT
EVAPORATORS
FILTRATE
\l/
^ — HP STEAM ^
\
/
SALT SETTLER
\
/
DRYER a COOLER
SCRUBBERS
\
_^ FILTRATE
^TO SEWER
/
SETTLERS
\
DUST
NATURAL GAS
78% DRYERS
AND COOLERS
MILL WATER
TO SEWER
1 ^MILL WATER
-, 1 ^
1 >
c
/
STRONG TANK
\
/
PREHEATERS
PRECONCENTF
\
/
AND
CONCENTRATING
PANS
\
/
FLAKERS
^ COLLECTION
^ CONDENSATE
^ (USED AS HOT
WATER)
\ OVERFLOW
^*TO SEWER
£ OVERFLOW
^TO SEWER
^OVERFLOW
^TO SEWER
< HP STEAM
^CONDENSATE TO
^^BOILER HOUSE
< LP STEAM
NATURAL GAS
v. 94%
^ DRYER -COOLER
FIGURE 51
CALCIUM CHLORIDE RECOVERY PROCESS
AT PLANT 166
135
-------
Table 19 shows the raw wastes produced in this recovery operation
and some other data. The principal waste is a contaminated
sodium chloride co-product which is discarded, as well as some
calcium chloride from condensates and spills. Water use for this
recovery process is:
A. Water Inputs to Plant
Ty.E§
River
Lake
Municipal
l/kkg_ of 100 percent
'
3,910 (938)
118,500 (28,400)
434 (104)
Comments
Steam generation
Cooling
Steam generation
B. Water Usage
1 /kkq of 100 percent
~
Cooling
Process
118,500 (28,400)
3,850 (923)
The present recovery unit reduces the effluent calcium chloride
by about 21 percent. This is because of the limited market for
calcium chloride. According to the manufacturer, if more of the
material could be marketed, more would be recovered. An
evaporation process for its recovery, as can be seen from this
discussion, is already operative. This recovery step, as it is
now practiced, also reduces the sodium chloride effluent of the
Solvay process by 4 percent.
Table 20 shows verification measurements on the water intake, the
calcium chloride cooling water, the final effluent and the soda
ash cooling water.
Sodium chloride
scdium chloride is produced by three methods:
1) Solar evaporation of seawater;
2) solution mining of natural brines;
3) Conventional mining of rock salt.
a) Solar evaporation process
In the solar evaporation process, sea water is concentrated by
evaporation in open ponds to yield a saturated brine solution.
After saturation is reached, the brine is then fed to a
crystallizer, wherein sodium chloride precipitates, leaving
136
-------
A.
TABLE 19. Calcium Chloride Recovery Process
Product
1. Soda ash distiller waste
2. Chlorine
3. Carbon dioxide 40% C02
4. Captive steam and power
B. Raw Waste Loads
Wastei J'rgductg
1. Ash and cinders
2. Water purification
sludge
3. NaCl co-product
4. CaC12
Process Source
Steam and power
Steam
Evaporation
Condensates and
spills
kg/kkg (Ib/ton)
of Product*
42.5(85)
0.75(1.5)
235(470)
35-50(70-100)
C. Comments
Ratio of CaCl2 to NaCl available in distiller waste is
approximately 1.4. Market demand at this location is
at a ratio of 10.6 to 1.
*Product is 100% calcium chloride.
137
-------
TABLE 20-
Verification Measurements at Plant 166
Parameter*
Flow, cu m/day
Temperature, °C
Color (Apparent)
APHA Units
Turbidity, FTU
Conductivity,
micromhos/cm
Suspended Solids
pH
Acidity: Total
Free
Alkalinity (Total)
Hardness: Total
Calcium
Halogens: Chlorine
Chloride
Fluoride
Sulfate
Phosphates (Total)
Nitrogen (Total)
Heavy Metals: Iron
Chror
Oxygen (Dissolved)
COD
*mg/l unless otherwise specified.
Water
Intake
Not
Measured
11,2
20
10
2000 (NaCl)
3800
5
7.80
0 CaC03
0 "
P 0 "
T 195 "
1300"
1250"
0.1
1525
0.45
170
1.1
0.55
0.07
ite 0.01
4.7
175
CaC12
Cooling
Water
Not
Measured
23.8
35
15
; 4000
7500
10
7.95
0
0
0
190
1400
1350
0.6
2600
0.55
170
1.2
0.58
0.18
0
7.7
-
Final
Effluent
17,400
-
275
0
67,000
118,000
170
10.8
0
0
460
610
45,000
45,000
0
50,000
1.36
640
0.7
1.7
0.48
0
4
-
Soda Ash
Cooling
Water
Not
Measured
ii
110
5
21,000
4,400
30
7.8
0
0
0
240
1,270
1,120
1.7
1,350
0.6
190
1.6
0.48
0.12
0
10
_
138
-------
behind a concentrated brine solution (bittern) consisting of
sodium, potassium and magnesium salts. The precipitated sodium
chloride is recovered for sale and the brine is then further
evaporated to recover additional sodium chloride values and is
then either stored, discharged back to salt water or further
worked to recover potassium and magnesium salts.
In the solar evaporation process, all of the wastes are present
in the bittern solution. Typical bittern analysis for the
exemplary 059 facility is given in Table 21. No bittern is
discharged from this facility. The bittern is stored and, in the
past, has been worked for recovery of other materials.
At plant 059, treatment consists of storage and further use of
the bittern materials. The plant water usage is:
Type
Use
cu m/day
Process Refining
process
Process Raw Material
2,270
(0.60)
327,000
(86. U)
1/kkg
(gal/ton)
894
(214)
129,000
(30,900)
Recycle
100 percent
- None
As the bitterns are stored and further worked, there is no
discharge. Eventual total evaporation after further bittern use
yields only solid wastes. Sufficient land and ponding area is
available at the 059 facility to store bitterns for the next 30-
50 years.
b) Solution brine-mining process
Saturated brine for the production of evaporated salt is usually
obtained by pumping water into an underground salt deposit and
removing the saturated salt solution from an adjacent interconn-
ected well, or from the same well by means of an annular pipe.
Besides sodium chloride, the brine will contain some calcium
sulfate, calcium chloride, magnesium chloride, and lesser amounts
of other materials including iron salts and sulfides.
The chemical treatment given to brines varies from plant to plant
depending on the impurities present. Typically, the brine is
first aerated to remove hydrogen sulfide and, in many cases,
small amounts of chlorine are added to complete sulfide removal
and oxidize all iron salts present to the ferric state. The
brine is then pumped to settling tanks where it is treated with
soda ash and caustic soda to remove most of the calcium,
magnesium and iron present as insoluble salts. After
clarification to remove these insolubles, the brine is sent to
multiple-effect evaporators. As water is removed, salt crystals
form and are removed as a slurry. After screening to remove
lumps, the slurry is washed with fresh brine to remove fine
139
-------
TABLE 21, Chemical Analysis of Bittern
Parameter*
pH
Total
Total
Total
Total
Solids
Volative Solids
Suspended Solids
Dissolved Solids
Alkalinity as CaCOa
BOD
COD
Ammonia as N
Kjeldahl Nitrogen Total
Nitrate as N
Phosphorus Total as P
Chloride
Cyanide
Fluoride
Phenols
Sulfate as S
Sulfide as S
TOC
Aluminum
Arsenic
Cadmium
Calcium
Chromium
Iron
Mercury
Sodi urn
Titanium
Zinc
7.8
241550
86600
1760
239790
2800
198
6350
0.702
32.610
37.50
0.22
158000
0.04
74.90
0.064
21000
2
900
2.5
0.04
0.02
450
0.02
6.5
0.001
5500
0.02
0.19
* All units mg/1 unless otherwise specified.
140
-------
crystals of calcium sulfate from the mother liquor to the slurry.
These sclids are returned to the evaporator. The calcium sulfate
concentration in the evaporator eventually builds up to the point
where it must be removed by "boiling Out" the evaporators.
The washed slurry is filtered, the mother liquor is returned to
the evaporators, and the salt crystals from the filter are dried
and screened. Salt thus produced from a typical brine will be of
99.8 percent purity or greater. Some plants do not treat the raw
brine, but control the calcium and magnesium impurities by
watching the concentrations in the evaporators and bleeding off
sufficient brine to maintain predetermined levels. By such
methods, salt of better than 99.5 percent purity can be made. In
either case, the final screening of the dried salt yields various
grades Depending on particle size. The facility at plant 030 is
similar to the standard flow diagram shown in Section IV.
A detailed list of the raw wastes and their process sources is
shown below. These include wastes from the multiple evaporators
and dryers, sludges from basic purification, as well a.s water
treatment chemicals used for the cooling water:
Waste Products Process Source Aver, kg/kkg of Product (Ib/ton)
NaOH
Na3PO4
Na2SiO3
Na2SO3~
NaCl & CaS04
NaCl
NaCl
NaCl
Brine sludges
Boiler Slowdown
Purge from multiple
evaporator
Evaporator
Barometric condenser
Miscellaneous sources
Brine purification
0.0055
0-0015
0.0025
0.0015
0.045
0.04
1.1
(0.011)
(0.003)
(0.005)
(0.003)
(0.090)
(0.08)
(2.2)
91 kkg/year
(100 ton/year)
The brine sludges
and disposal.
are returned to the brine wells for settling
Well water for brine field use is taken into the plant at a rate
of 2,240 1/kkg of product (536 gal/ton). Lake water for cooling
and other uses is drawn into the plant at a rate of 48,000 1/kkg
(11,400 gal/ton).
Use
Cooling (barometric
condensers)
Other (dust collection
pumps)
Flow
41,700 1/kkg
(10,000 gal/ton)
6,400 1/kkg
(1,540 gal/ton)
none
90 percent
141
-------
Treatments of the effluent streams are as follows:
Source
condenser Discharge
Storm Drain
Tunnel Line (Lake Water)
Ash Lime Discharge
Treatment
To Lake
To Lake
To Lake
Recycled
The storm drain flow cited above was 3,790 1/kkg of product (910
gal/ton) on the average,
The plant effluent streams #1 and #2 after treatment consist
solely of streams containing 100 mg/1 chloride at a pH of 8.2.
Chloride concentration at the plant intake was given as 70-80
mg/1, with a pH of 8.2. Table 22 shows verification measurements
on the plant intake and condenser discharge (stream #1) effluent.
The chloride content and pH as stated are verified within a
reasonable margin.
sodium Dichromate and Sodium Sulfate
sodium dichromate is prepared by calcining a mixture of chrome
ore (FeO.Cr203), soda ash and lime, followed by water leaching
and acidification of the soluble chromates. The insoluble
residue from the leaching operation is recycled to leach out
additional material.
During the first acidification step, the pH of the chromate
solution is adjusted to precipitate calcium salts. Further acid-
ification converts it to the dichromate and a subsequent
evaporation step crystallizes sodium sulfate (salt cake) out of
the liquor. The sulfate is then dried and sold. The solutions
remaining after sulfate removal are further evaporated to recover
sodium dichromate. Chromic acid is produced from sodium
dichromate by reaction with sulfuric acid, sodium bisulfate is a
by-product. Figure 52 shows a detailed flowsheet for the
exemplary facility at plant 184.
Plant 184 manufactures only sodium dichromate and chromic acid.
However, some other chromate plants do convert part of their
chromic acid products to potassium dichromate. All of this
latter material is made in plants that produce other chromates.
The raw waste loads expected from the manufacture of sodium
dichromate and its by-product sodium sulfate are given below.
The bulk of the waste originates from the undigested portions of
the ores used. These materials are mostly solid wastes. The
wastes arising from spills and washdowns contain most of the
hexavalent chromium. The wastes from water treatment and toiler
142
-------
TABLE 22.
Verification Measurements at Plant 030
Parameter*
Flow, cu m/day (MGD)
Temperature, °C
Color, APHA Std.
Turbidity(FTU)
Conductivity(NaCl)
Suspended Solids
PH
Acidity: Total
Free
Alkalinity (Total)
Hardness: Total
Calcium
Halogens: Chloride
Sulfate
Phosphates
Nitrogen
Heavy Metals: Iron
Oxygen (Dissolved)
COD
Intake
37,900(10)
13
40
10
225
0
8.0
0
0
0
139
171
128
65
13
0.07
0.17
0.24
55
Condenser
Discharge
37,900(10.0)
22.5-23.0
40
15
320
0
8.1
0
6
0
140
189
147
120
37
0.1
0.17
0.23
2.8
50
*mg/l unless otherwise specified.
143
-------
SI/LFURIC ACIC
SULFURIC ACID
1 1
CHROMIC
ACID
REACTOR
1
ACICIFIEH
1
EVAPORATOR
,
EVAPORATOR
x
.
FILTER
,
i
SODIUM
BICHROMATE
LI8UOH
FIGURE SZ
CHROMATE MANUFACTURING FACILITY
AT PLANT 184
144
-------
blowdowns are principally dissolved sulfates and chlorides. The
manufacture of chromic acid contributes no additional wastes.
Waste Product
1. Chromate wastes
(Materials net
digested in H2S04)
2. Washdowns*
spills, etc,
3. Blowdown
Process source
Residues
Boilers and
cooling
towers
kg/kkg of Na2Cr207
Pio&^i lib/ton) *
""
900(1800)
0.75(1.5) 0.5-1(1-2)
0.5-1(1-2)
*lncludes contributions from the chromic acid unit.
Water intake to this facility consists of river water and well
water in the following amounts based on sodium dichromate pro-
duct: 12,700 1/kkg (3,030 gal/ton) and 1,840 1/kkg (440 gal/ton)
respectively. The boiler feed comes from the river water feed
and is softened prior to use. The well water is all filtered,
softened and chlorinated.
Water^Use:
Ty.i>e
Cooling
Products and
Evaporation
Waste Treatment
Sanitary
1/kkg of sodium
dichromate (cral/toni
275,000 (66,000)
5,UOO ( 1,300)
8,860 ( 2,120)
255 ( 60)
Percent Pecvcled
98.2
0
Waste waters are treated with pickle liquor to effect reduction
of chromates present. All effluent waters are lagooned to settle
out suspended solids. This treatment removes 99 percent of the
hexavalent chromium and the discharge contains 0.01 mg/1. The
lagoon discharges to a nearby river when full.
All rainwater, washdowns, spills and minor leaks in the part of
the plant which handles hexavalent chromium are captured in the
area's sumps and used in the process. storage facilities are
provided to contain a heavy rain and return the water either to
the process or to treatment. Separate rainwater drainage is
provided for areas not handling hexavalent chromium. Sewers are
continuously monitored. A batch system is used in the treatment
process. Each batch is treated and analyzed before release to
the lagoon.
145
-------
TABLE 24. Analysis of River Water atpiant 134
Parameter
Color, APHA Units
Turbidity, FTU
Conductivity
Suspended Solids
PH
Alkalinity (Total)
•Hardness: (Total)
(Calcium)
Halogens: Chloride
Sulfate
Phosphate
Nitrate
Heavy Metals: Iron
Chromium (Cr+6)
Measurements (mg/1 unless
otherwise specified
270
5
35 NaCl eq,
5
6.59
phen-O/Total-20 (as CaC03)
23 (as CaC03)
15
11
0
0.38
0.13 (as N)
1.5
0*
*less than 20 mcg/1
148
-------
blowdowns are principally dissolved sulfates and chlorides,
manufacture of chromic acid contributes no additional wastes.
The
Waste Product
1. Chromate wastes
(Materials net
digested in
2. Washdowns*
spills, etc.
3. Blowdown
Process source
Residues
Boilers and
cooling
towers
kg/kkg of Na2Cr2O7
E^S^HSi Jib/ton)
Average Range
900(1800)
0.75(1.5) 0.5-1(1-2)
0.5-1(1-2)
*lncludes contributions from the chromic acid unit.
Water intake to this facility consists of river water and well
water in the following amounts based on sodium dichromate pro-
duct: 12,700 1/kkg (3,030 gal/ton) and 1,840 1/kkg (440 gal/ton)
respectively. The boiler feed comes from the river water feed
and is softened prior to use. The well water is all filtered,
softened and chlorinated.
1/kkg of sodium
dichromate (gal/ton)
275,000 (66,000)
5,UOO ( 1,300)
8,860 ( 2,120)
255 ( 60)
Type
Cooling
Products and
Evaporation
Waste Treatment
sanitary
98.2
0
0
0
waste waters are treated with pickle liquor to effect reduction
of chromates present. All effluent waters are lagooned to settle
out suspended solids. This treatment removes 99 percent of the
hexavalent chromium and the discharge contains 0.01 mg/1. The
lagoon discharges to a nearby river when full.
All rainwater, washdowns, spills and minor leaks in the part of
the plant which handles hexavalent chromium are captured in the
area's sumps and used in the process. Storage facilities are
provided to contain a heavy rain and return the water either to
the process or to treatment. Separate rainwater drainage is
provided for areas not handling hexavalent chromium. Sewers are
continuously monitored. A batch system is used in the treatment
process. Each batch is treated and analyzed before release to
the lagoon.
145
-------
Data on the effluent from this
facility are presented below:
exemplary chrornate treatment
Average
Range
Flow, liters/kkg (gal/ton)
Total Suspended Solids, mg/1
Total Dissolved Solids, mg/1
pH
Cr43,
mg/1
cr+6, mg/1
8,860 (2,120)
14 1-24
10,000 5,000 - 13,000
(mostly chlcrides)
7.2 6.0 - 8.5
0.14 ' 0.01 - 0.31
(mostly in form of suspended solids)
0.01
The chromium content has been significantly reduced. However,
the amount of sodium chloride being discharged is significant.
Based on the porous nature of the present lagoon walls and the
high dissolved solids content discharged into the river, this
plant is considered exemplary only from the standpoint of
chromate control and treatment.
Table 23 gives a more detailed presentation for the river intake
and plant effluent from this facility. The composition of river
water taken near the plant and the plant effluent determined on
two separate occasions are shown as a range of values. These
data were furnished by the plant.
Tables 24 and 25 present data obtained by sampling for this
facility. Table 24 shows an analysis of river water drawn
adjacent to the plant. Table 25 shows the compositions of waste
stream before and after passage through the pickle liquor
treatment unit.
sodium Metal
Sodium is manufactured by electrolysis cf molten sodium chloride
in a Downs electrolytic cell. After salt purification to remove
calcium and magnesium salts and sulfates, the sodium chloride is
dried and fed to the cell, where calcium chloride is added to
give a low-melting CaCl2-NaCl eutectic, which is then
electrolyzed. sodium is formed at one electrode, collected as a
liquid, filtered and sold. The chlorine liberated at the other
electrode is first dried with sulfuric acid and then purified,
compressed, liquified and sold. Figure 53 shows the process in
use and waste treatment facilities at plant 096.
There is no waste during operation of an individual cell for the
molten salt electrolysis step in the Downs cell process. The
cells are run in banks, and individual cells are cleaned out and
refilled after the electrolyte is depleted. All of the wastes
arise from this cleaning and refilling of individual cells.
146
-------
TABLE 23. Intake and Effluent Composition at Plant 184
Parameter
Total solids
Organic Solids
Mineral Solids
Alkalinity as caCO3 (methyl-orange)
Alkalinity (phenolphthalein)
Free Carbon Dioxide
Total Hardness (as CaCO3)
Total Hardness (grains per gallon)
Analysis of Mineral solids:
silica (Sio2)
Iron Oxide 7^^203)
Alumina (Al£o3f
Lime (CaO) ""
Magnesia (MgO)
Sulphate (SO3)
Chloride (Clf
Soda (Na20)
Manganese (Mn)
Fluoride (F)
Biochemical Oxygen Demand (BOD5)
Color (Pt-Co)
Chromium (Cr)
Tannin
~#mg7l~unless~otherwise specified
**None found
River
Hater
79
45
3U
2.0
0.0
1.6
15
0.88
6.4
2.6
0.4
0,8
5.6
2.0
6.8
8.9
5.7
0.0
0.0
Plant
330-334
93-10U
230-232
0.0
0.0
1.0-17.0
209.3-238.7
12.2-12.8
7.4-8,4
5.0-6.0
O.l-a.3
0.0
114.4-115.5
0.8-5.0
3.4
1.3-1.8
8.2-10.4
0.0
0.0
less than 5
130
-
2.6
*#
**
147
-------
TABLE 24. Analysis of River Water atpiant 134
Measurements (mg/1 unless
Parameter
Color, APHA Units
Turbidity, FTU
Conductivity
Suspended solids
PH
Alkalinity (Total)
•Hardness: (Total)
(Calcium)
Halogens: Chloride
Sulfate
Phosphate
Nitrate
Heavy Metals: Iron
Chromium (Cr+6)
270
5
35 Nad eq.
5
6.59
phen-O/Total-20 (as CaC03)
23 (as CaC03)
15
11
0
0.38
0.13 (as N)
1.5
0*
#less than 20 mcg/1
148
-------
TABLE 25- Analysis of Waste Treatment Streams
at Plant 184
Parameter
Flow
Temperature, °C
Color
Conductivity
Dissolved Solids
Suspended solids
pH
Alkalinity (Total)
Hardness: Total
Calcium
Halogens: Chloride
Sulfate
Phosphate
Nitrate
Heavy Metals:
Chromium (Cr+6)
Iron
Oxygen (Dissolved)
Before Treatment
Batch volume -:
28,700 liters
49
500 (supernatant
liquid)
5000 NaCl
10,700
170,000
10 (straight);
9.3 (dilution)
phen*0/total-1000
(as cacO3)
600 (as CaCO3j
520 (as Caco3)
310
3,900
0.7
9.8 (as N)
1,300
10.4
After Treatment
Batch volume -
30,400 liters
61
70
14,500
18,000
154,000
9.1 (supernatant,
fresh);
8.4 (filtered,
30 days old)
phen-2/total-23
(as CaCO3)
6,000
6,000
8,700
1,900
0.7
0.01
0.60
*mg/l unless otherwise specified.
149
-------
o
o
O
SALT-
PROCESS
EQUIPMENT REPAIR
PRODUCT PURIFTCAT10N
WATER, Fe
V
U
i i
u
(£
m
OZ
V V v
si £
fe 1
,y o
o i-
5-
FIGURE 53
WASTE TREATMENT ON DOWNS CELL AT PLANT 096
-------
The wastes produced by sodium manufacture at plant 096 are shown
below. Several of the expected wastes are not present. This is
due to the reuse of materials in other parts of the facility to
make other products. For example, the sulfuric acid used in
drying the chlorine is reused.
Waste Products
Process source
NaCl Process
Misc, Alkaline Salts Process
Ca (OCl)2 Chlorine Recovery
Fe Cooling Tower
kg/kkg_of Product
50-65 (100-130)
25-35 (50-70)
45-75 (90-150)
0.065-0.095 (0.13-0.19)
The process does not normally shut down,
from the replacement of cells.
The discharges result
Cooling tower blowdowns and residual chlorine from tail gas
scrubbers are discharged without treatment. The stream
containing calcium hypochlorite wastes is used to treat cyanide
wastes. Cooling water is discharged without treatment and tank
wash and runoff water are first ponded to settle out suspended
materials and then discharged.
The water input to the plant is well water in the amount of 2,730
cu m/day or 46,300 1/kkg of product (11,100 gal/ton), having an
impurity content of:
110-125 mg/1 ,
30-60 mg/1
80-100 mg/1
1-3 mg/1
0.02-0.06 mg/1
0.02 mg/1
2-7 mg/1
Total Solids
C02
Hardness (as Ca)
Fe
Cu
Zn
Sulfate
Alkalinity (CaCO3)
70-100 mg/1
The water use within the plant is as follows:
U se Flow Amount
Ceding 29,100 cu m/day
(7.7 mgd)
Process 530 cu m/day
(0,14 mgd)
497,000 1/kkg
(119rOOO gal/ton)
9,000 1/kkg
(2,150 gal/ton)
Table 26 lists the various plant waste streams and their
compositions.
These stream effluents consist mostly of dissolved sodium chlor-
ide and other chlorides. Table 27 shows the results of analyses
of simultaneous samples from three of the waste streams (those
151
-------
TABLE 26. Plant 096 Effluent
Parameter*
Flow, cu m/day
(MGD)
TSS
TDS •
BOO
COD
PH
Fe
Chloride
Chlorine
Sulfate
Total Hardness
Phosphate
Turb1d1ty(FTU)
Color(APHA)
Addlty(Free)
Alkalinity
(Total)
Hardness (Ca)
Stream No.
1**
409(0.108}
30-50
400-600
-
_
6.5-7.5
2
100-150
-
-
-
0.2
25-30
15
20-30
.
-
Stream No.
2***
133(0.035)
50-70
.
-
_
10.5-12.0
1-2
10,000-30,000
4,000-6,000
-
-
-
40-60
15
20-30
4,000-6,000
25,000-30,000
Stream No.
3****
1,780(0.470)
5-10
-300-400
-
-
6.7-7.5
2-3
50-100
20-100
25-50
180-225
-
125
15
-
-
-
Stream No.
4*****
409(0.108)
-
-
-
-
_
-
13,000
-
• - •
-
-
-
-
-
-
.
*A11 units mg/1 unless otherwise specified.
**Coo11ng Tower Slowdown, C12 Residual.
***Ca1c1um hypochlorlte used to treat cyanide wastes In another
process.
****Cool1ng water.
*****Runoff, excess calcium hypochlorlte, tank washup.
Note: There Is also 2,270 liters/day (600 GPD) used sulfurlc
add sent for use elsewhere In the complex and not dis-
charged Into surface streams.
152
-------
TABLE 27. Plant 096 Effluent
Parameter*
Flow, cu m/day (MGD)
Plant
VM**
Temperature, °C
Plant
VM
Color(True),
APHA Units
Plant
VM
Turbidity,
Jackson Units
Plant
VM
Suspended Solids
Plant
VM
Dissolved Solids
Plant
VM
PH
Plant
VM
Acldlty(Free)
Plant
VM
Alkal1n1ty(CaC03)
Plant
VM
Chlorine
Plant
VM
Chloride
Plant
VM
Sulfate
Plant
VM
Fe
Plant
VM
Stream No.
2
-
133(0.035)
- .
21.5
15
300
26
82
39
39
574
479
6.5
6.55
19.5
-
48
0
0
121
125
-
-
0.33
0.22
Stream No.
3
-
1,590(0.42)
-
22
15
30
25
10
6
11
355
266
6.45
6.44
37.5
•
57
0.6
0.2
92
90
26
10
0.69
2,7
Stream No
4
.
-
-
20
15
260
58
45
137
90
_
35,800
11.9
11.9
-
-
4,500
64,000
2,400
17,800
26,500
_
-
0.92
0.7
*mg/l unless otherwise specified,
**Ver1f1cation measurement
153
-------
corresponding to streams 2, 3, and 4 of Table 26).
agreement between the results was generally obtained.
Good
This facility has good pH and suspended solids control and reuse
of some wastes, but there are large amounts of chlorides being
discharged which may be recycled for process reuse.
Sodium Silicate
Sodium silicate is manufactured by the reaction of soda ash or
anhydrous sodium hydroxide with silica in a furnace, followed by
dissolution of the product in water under pressure to prepare
sodium silicate solutions. In some plants, the liquid silicate
solutions are then further reacted with sodium hydroxide to
manufacture metasilicates which are then isolated by evaporation
and sold. Figure 54 shows the total system diagram for plant
072.
The raw waste loads for plant 072 are listed below. These wastes
consist mostly of sodium silicate and unreacted silica:
Waste Products
sodium silicate
Silica
NaOH/Silicates
Process Source
Scrubbers
Scrubbers
Washdowns
Avg. kg/kkg of
Dry Basis product (Ib/tonl
37 <7U)
2.85 (5.7)
0.39 (0.78)
Data on in-plant water use could not be obtained from plant 072.
However, the water use data from another plant (134) is given
below on the basis of unit weight of product (dry basis). The
water intake is 2/900 1/kkg (710 gal/ton) which is -used as
follows:
Water Use
Process water
Boiler blow-down, compressor
cooling. Wash-down, Tank
cleaning, and misc.
Steam, Evaporation, and
other losses
1/kkg (gal/ton)
1,020 (245)
610 (147)
1,330 (319)
At plant 072 all scrubber and washdown waters are sent to a
totally enclosed evaporation pond. There is no plant effluent.
Sodium Sulfite
Sodium sulfite is manufactured by reaction of sulfur dioxide with
soda ash. The crude sulfite formed in this reaction is then
purified, filtered to remove insolubles from the purification
154
-------
GLEAM
GAS WATER
WATER VAPOR, DUST
NaOH( MOLTEN)
Si02
FURNACE
SCRUBBER
SILICATE GLASS
COOLER
WATER TO
EVAPORATION POND
GRANULIZER
SILICATE PRODUCT
FIGURE 54-
SODIUM SILICATE MANUFACTURE AT PLANT 072
-------
step, crystallized, dried and shipped.
plant 168 is given in Figure 55.
A process diagram for
A listing of the raw wastes produced from sodium sulfite produc-
tion is given below. These consist Of sulfides from the purifi-
cation step and a solution produced by periodic vessel cleanouts
containing sulfite and sulfate.
Waste Products Process Source
Metal sulfides
Na2SO3/Na2S04
scluticn
Na2SO3/Na2SO4
scluticn
Filter wash
Dryer ejector
Process cleanout
0.755
(1-51)
(0.38-2.88)
Cleanouts of various process vessels produce shock loads up to
9.1 kkg (10 tons) of sodium sulfite and sulfate (dry basis).
Cleanouts are conducted 376 times per year. For this, separate
tanks are used for surge capacity with bleed into the treatment
unit over a 5-10 day period.
Approximately 244 cu m/kkg of product (57,600 gal/ton) of river
water and 290 to 630 1/kkg (70 to 150 gal/ton) of municipal water
are taken into the plant. The stated analysis and verification
of the river intake is:
Parameter
Suspended
Solids
POE
Iron
Copper
Chromium
Zinc
Nickel
Lead
Dissolved
Solids
Stated, Concentration Cmq/1)
Average
(6.80)
28
14.8
2.6
0.02
0.01
0.49
0.01
0.02
5.68-7.12
10-45
1.4-38.5
1.5-4.9
0.01-0.02
0.01-0.02
0.08-1.84
0.01-0.02
0.01-0.07
Verification
Meafeuremen-t (mg/1)
7.00
10
0.9
0.1
168
The in-plant use of the water intake is as follows:
Use
Indirect cooling
Process (conden*
sate)
Dryer, Ejector
Filter Wash
Approx. 244,000(57,600)
Approx. 170 (40)
290 to 630
(70 to 150)
Percent, Recycle
0
0
156
-------
SMALL RECYCLE
COOLER
RIVER WATER
REACTOR
NaOH
CuClg
NaHS;
TREATMENT
CITY
WATER"
FILTRATION
CONDENSATE
WATER
CRYSTALLIZATION
CENTRIFUGE
C1TY_
WATER
DRYING
PRODUCT
Na2S03
r
OXIDATION
I
I
MX
HOLDING
FILTRATION
SOLIDS CLEAN
WATER
U¥A
FIGURE 55
SODIUM SULFITE PROCESS FLOW DIAGRAM
AT PLANT 168
157
-------
The principal waste streams operating on a continuous basis
consist of flows from the dryer ejector and filter washing
operations. These waters are treated by aeration and filtration
prior tc discharge. Vessel washouts are also subjected to the
aeration and filtration procedure. The performance experience of
oxidation and filtration treatment processes at this plant is:
Method
Oxidation
Filtration
Qualitative
Rating....
Excellent
Excellent
Waste^ReductionnAccomelished
94 percent oxidation of sulfite to sulfate
98 percent suspended solids removal
Compositions of the process effluents streams after treatments
are given below. The waste stream after aeration treatment and
after it has been subjected to a final filtration prior to
discharge are shown. The cooling stream, which consists of
untreated river water, has the same composition as measured at
the intake. Measurements for verification of the process
effluents and cooling water are given in Tables 28 and 29,
respectively.
Parameter
TSS (ing/I)
TDS (mg/1)
BCC5
COD
PH
Temperature
Sulfuric Acid
After Aeration
Ave. Range
2,200 700-4, 100
57,000 46,000-70,000
56.8 mg/1 46-71 mg/1
118 mg/1 64-161 mg/1
9.8 9.7-9.9
65°C
After Final Filtration
Aye .
97 3-240
57,000 46,000-70,000
56.8 mg/1 46-71 mg/1
118 mg/1 64-161 mg/1
9.8 9.7-9.9
43°C 38-49°C
Sulfuric acid is manufactured primarily by the contact process
which involves catalytic oxidation of sulfur dioxide to sulfur
trioxide and reaction of the sulfur trioxide with water to yield
sulfuric acid, within the contact process, there are three types
of plants.
(1) Double absorption - paired sulfur trioxide absorption towers
and catalyst beds in series are used to maximize conversion of
sulfur dioxide so that tail gas scrubbers are not required.
(2) Single absorption - single absorption towers and catalyst
beds are used and tail gases frequently have to be scrubbed to
remove sulfur oxides; and
158
-------
TABLE 28. Measurements of Plant 168 Process Waste
Streams Before and After Treatment
Parameter*
Flow
Temperature, °C(°F)
Col or(Apparent) APHA Std,
Turbidity, FTU
Total Dissolved Solids
Total Suspended Solids
pH
Alkalinity (Total) P
Hydrogen Sulfide
Sulfite
COD
Before**
(Batch Process)
76.7(170)
500
500
88,200
780
11.0
9,000
24,000
0
60,000
8,000
After
(Batch Process)
76.7(170)
500
380
93,900
2,010
11.2
500
800
0
170
250
*mg/l unless otherwise specified.
**This sample was collected from the full oxidation tank just
before the waste treatment process was begun. This was nec-
essary because the waste lines to the tank are not accessible
for sampling and the only outlet valve is on the tank itself.
159
-------
TABLE 29. Plant 168 Cooling Water Measurements
Parameter*
Temperature! °C
Col or(Apparent) APHA Std.
Turbidity, FTU
Conductivity, as NaCl
Suspended Solids
PH
Acidity: Total
Free
Alkalinity (Total) P
T
Hardness: Total
Calcium
Halogens: Chlorine
Sulfate
Phosphates
Nitrate
Heavy Metals: Iron
Hydrogen Sulflde
Sodium SulfHe
*mg/l unless otherwise specified.
Intake
17
95
25
130
10
7.00
0
0
0
40
73
50
24
53
0.72
0.33
0.86
0
3
Effluent
21
65
15
120
8
7.08
0
0
0
40
76
51
24
55
0.66
0.32
0.78
0
160
-------
(3) Spent acid plants - these plants use spent sulfuric acid in
place of, or in addition to, sulfur as a raw material. While the
acid production parts of these plants are the same as those for
single absorption, these plants are unique because of the spent
acid pyrolysis units used to convert the waste sulfuric acid raw
materials to a sulfur dioxide feed stream.
In this section, only the first two types of plants are
considered.
Double Absorption
In the double absorption contact process, sulfur is burned to
yield sulfur dioxide which is then passed through a catalytic
converter with air to produce sulfur trioxide. The sulfur
trioxide is then abosrbed in 95-97 percent sulfuric ac^d. The
gases emerging from the absorber are fed to a second converter to
oxidize the remaining sulfur dioxide to sulfur trioxide which is
then absorbed in a second absorption tower. The tail gases are
vented to the atmosphere- Figure 56 shows a detailed process
flow sheet for plant 086.
At plant 086, only cooling water is discharged. In double
absorption plants, the tail gases are sufficiently depleted to
sulfur oxides that there is no need for gas scrubbers. Alsq, at
this plant, use of extensive maintenance and leak prevention has
been employed to prevent discharge of any product acid.
The table below shows water usage at plant 086. Most water is
used for cooling. Process water is consumed to make sulfuric
acid and is not discharged. The only plant effluent is the cool-
ing water used in the heat exchangers and associated water treat-
ment chemicals.
Water Inputs to Plant:
Type cu m/day (mgd)
River
Municipal
Comments
35,200 (9,30) 55,600 (13,300) Used for cooling
only
1,020 (0.27) 1,610 (386) Used for process
steam and cooling
Water Usage;
Type Source
cu m/davfrnqd) 1/kkg(gal/ton) Percent Recycled
Cooling River 35,200 (9.30) 55,600 (13,300)
Municipal 295 (0.078) 463 (HI)
Process Municipal 117 (0.031) 184 (44)
Steam Municipal 610 (0,161) 960 (?30)
161
-------
MUNICIWL WATER—5>
SOFTENER
LEGEND:
I
BACK WASH
TO RIVER
WATER OR STREAM FLOW
PROCESS FLOW
CONDENSATE
FEED
WATER
HEATER
MUNICIPAL WATER-
SULFUR
JLFUR AIR
X X
SULFUR
BURNER
EXPORT STEAM I
WASTE
HEAT
BOILERS
SLOWDOWN
TO RIVER
CONVERTER
AND
ABSORPTK)N
SYSTEM
STEAM
BLOWER
TURBINE
PROCESS
HEATING
RIVER WATER
W
ACID
COOLERS
I
SULFURIC
ACID
TO
RIVER
FIGURE
DOUBLE ABSORPTION CONTACT SULFURIC ACID PROCESS
FLOW DIAGRAM AT PLANT 086
-------
The only effluent from this facility is once-through cooling
water. Table 30 shows verification measurements for the water
intake and effluent.
single Absorption
The single absorption process differs from that previously
described only in the arrangement of converters and absorbers.
The rest of the process is the same. For the single absorption
process, the sulfur dioxide is passed through one or more
converters and then into one or more absorbers prior to venting
to the atmosphere. This arrangement is less effective for both
conversion of sulfur dioxide to sulfur trioxide and for
absorption of the sulfur trioxide into the absorber sulfuric
acid. As a result, the tail gases may have to be scrubbed,
creating a waterborne waste not present for double absorption
plants. The exemplary plant is plant 141. •
For the single absorption sulfur-burning process, there are no
wastes from the sulfuric acid process itself, wastes arise from
the use of water treatment chemicals. The raw wastes are iron,
silicon, calcium and. magnesium salts from water treatment. This
does not cover spent acid plants based on single absorption.
Most of the cooling water used at this plant is recycled and only
5 percent emerges from the plant. This is sent to evaporation
ponds, from which there is no discharge. The water input is well
water in the quantity of 606 cu m/day (0.160 mgd) or 1,670 1/kkg
of product (400 gal/ton). This water is used as follows:
cu m/dav fmgd) 1/kkq (gal/ton)
cooling
Process
560
45.5
(0.148)
(0.012)
1,540 (370)
125 (30)
95
0
All waterborne wastes are sent to an evaporation pond. There is
no discharge. Table 31 shows verification measurements on the
intake water, the effluent going to the evaporation pond, and the
evaporation pond water, respectively.
Titanium Dioxide
a) Chloride process
Virtually the same process is used at the two chloride process
facilities studied (plants 009 and 160). The only process
differences lie in the types of ore used. Plant 160 employs a
unique process using an ore contai-ning 66 percent titanium
dioxide, while plant 009 uses only 95 percent plus grades of
rutile and upgraded ilmenite. Figure 57 and 58 show the process
flows within the 009 facility.
163
-------
TABLE 30« Intake and Effluent Measurements at
Plant 086
Parameter*
Intake
Flow cu m/day (MGD) Not Measured
Temperature, °C 13
Color (apparent - 40
APHA std.)
Turbidity (FTU) 10
Conductivity (as NaCl) 17,500
Suspended Sol ids 10
pH 7.5
Acidity: Total
Free
Alkalinity: (Total) P(CaC03)
T(
Hardness: Total(CaCOJ)
Calcium(CaC03)
Halogens: Chlorine
Chloride
Fluoride
Sulfate
Phosphates (Ortho)
Nitrate, N
Heavy Metals: Iron
Chromate
Oxygen (Dissolved)
Sulfite
COD
0
93
300
600
10,000
1 ,500
0.70
0.24
0.28
Effluent
11,350 (3.0)
26.5
40
15
18,000
5
7.43
91
3,200
590
10,000
1 ,500
0.68
0.26
0.32
rAll units mg/1 unless otherwise specified
164
-------
TABLE 31. In-Plant Water Streams at Plant 141
Sump to
Ponds
24.6
0
10
360
4700
8.5
0
0
0
120
250
112
0
20
0.6
340
0.64
0,18
9
0.16
5.5
575
*A11 units mg/1 unless otherwise specified.
Parameter*
Fl ow
Temperature (°C)
Color (Apparent-APHA)
Turbidity (FTU)
Conductivity (as NaCl )
Suspended Solids
PH
Acidity: Total
Free
Alkalinity (Total ) P
T
Hardness : Total
Calcium
Halogens: Chlorine
Chloride
Fluoride
Sulfate
Phosphates (Total }
Nitrogen (Total }
Heavy Metals : Iron
Chromate
Oxygen (Dissolved)
COD
Water
Unable to
measure
19
100
35
410
40
7.0
0
0
0
475
410
275
0
18.5
0.35
78
1.6
0.03
18
0
5.3
25
Evaporation
Pond
17.5
35
10
790
0
7,7
0
0
0
105
500
400
0
22.5
0.77
680
0.12
0
4
0.03
7.9
70
165
-------
The raw wastes from plant 009 consist of heavy metal salts, waste
coke and hydrochloric acid. In the raw waste stream, these are
actually metal chlorides before waste treatment. In detail, the
raw wastes are:
Constituents
Iron salts (equiv. Fe203)
other metal salts ~ "
(equiv. metal oxides)
Ore
Coke
Titanium hydroxide
Tio.2
HC1~
Ave. .kg/kkcf_ (Ib/ton) of product
58 (116)
58 (116)
138 (276)
23 (46)
29 (58)
40.5 (81)
227 (454)
Lake
Municipal
Use:
cooling
Process
Cleanup
Sanitary
Bciler feed
cu m/day Jrngd)
11,500 (0.304)
76 (0.020)
58,700
6,060
284
38
834
(15.5)
(1.6)
(0.075)
(0.01)
(0.22)
1/kkg jgal/ton)
17,100 (4,100)
1,130 (270)
876,000 (210,000)
90,500 (21,700)
4,220
560
12,500
(1,010)
(140)
(3,000)
Percent Recycled
93
0
0
0
0
Most of the cooling water is recycled. The waste treatment
methods used on the effluent stream, which consist of
neutralization, precipitation and settling of heavy metal salts
prior to discharge, are shown below. Figures 59 and 60 show the
treatment processing at plant 009.
Treatment
Stream No.
1
2
Source
TiC14 precipitation
Cooling
Neutralization,
settling
Neutralization,
settling
Lake
Lake
Table 32 shows the plant 009 effluents after neutralization and
settling treatment. The effluent consists of a neutral pH stream
containing dissolved salts (mostly sodium chloride) and low heavy
metals concentrations. Table 33 shows verification measurements
at this facility.
168
-------
TABLE 31. In-Plant Water Streams at Plant 141
Parameter*
Flow
Temperature (°C)
Color (Apparent-APHA}
Turbidity (FTU)
Conductivity (as NaCl )
Suspended Solids
pH
Acidity: Total
Free
Alkalinity (Total) P
T
Hardness : Total
Cal cium
Halogens: Chlorine
Chloride
Fluoride
Sulfate
Phosphates (Total }
Nitrogen (Total )
Heavy Metals: Iron
Chromate
Oxygen (Dissolved)
COD
Water
Unable to
measure
19
100
35
410
40
7.0
0
0
0
475
410
275
0
18.5
0.35
78
1 .6
0.03
18
0
5.3
25
Sump to
Ponds
24.6
0
10
360
4700
8.5
0
0
0
120
250
112
0
20
0.6
340
0.64
0,18
9
0.16
5.5
575
Evaporation
Pond
17.5
35
10
790
0
7.7
0
0
0
105
500
400
0
22.5
0.77
680
0.12
0
4
0.03
7.9
70
*A11 units mg/1 unless otherwise specified.
165
-------
WASTE SLUDGES
TiCl4 F
TiCl4 , FeClx
I
O^KE C CHLORINATOR -L* QUENCH ^ TiCU
COKE * CHLORINATUR >~3> TOWER ^CONDENSATION
TIT)
\^
WATER ^
WSTE
SLURRY
, , EVERYTHING EXCEPT
gQLjQ RECOVERED ORE^
WAS ItS
Fed^ORE, j ^ L
| p01^ . ORE /..
LIQUID ^
WASTES ^
HCI .. - ...
j Fed* j
ORE
•URJFICATION COOLING
CHEMICALS WATER
I 1
^ TiCU ^ TiC»4
^ PURIFICATION ^ STORAGE
COOLING WKTER V V
TiO2 TiCl4
PLANT SALES
_^ WASTE
~^ TREATMENT
FIGURE 57
WIUM TETRACHLORIDE PORTION OF TITANIUM DIOXIDE PLANT
-------
TiCl4 VAPOR
02.
PURCHASED BY PIPELINE-
COOLING WATER
CO
GENERATOR
Ogs
OXIDATION
REACTOR
COOLER
-SPENT COOLING WATER
fcWASTE TREATMENT
AT Ti02 OPERATION
COOLING FUTURE
WATER
1
™ T|-c.
TO T|CI4
—LIQUID CI2—>TiCI4 PROCESS
WASTE
-COOLING WftTER—> ^E^™EN
OPERATION
VARIOUS
TREATMENT
CHEMICALS
WASTE
WASTE TREATMENT^ \|/
AT TfCI4 OPERATION^
Ti02, SPILLS, SALTS
STORM DRAINAGE FROM Ti02 OPERATION
FINISHED
Ti°2
WASTE TREATMENT AT TJOg OPERATION
FIGURE 58
TITANIUM DIOXIDE PORTION OF PLANT (CHLORIDE PROCESS)
-------
The raw wastes from plant 009 consist of heavy metal salts, waste
coke and hydrochloric acid. In the raw waste stream, these are
actually metal chlorides before waste treatment. In detail/ the
raw wastes are:
Constituents
Iron salts (equiv. Fe2O3)
other metal salts
(equiv. metal oxides)
Ore
coke
Titanium hydroxide
Tip2
HCl"
Aye. kg/kkcr_ (Ib/ton) of .product
58 (116)
58 (116)
138 (276)
23 (46)
29 (58)
U0.5 (81)
227 (454)
Lake
Municipal
Use:
Cooling
Process
Cleanup
Sanitary
Bciler feed
cu in/day _(mqcl)
11,500 (0.304)
76 (0.020)
58,700
6,060
284
38
834
(15.5)
(1.6)
(0.075)
(0.01)
(0.22)
1/frkcf jgal/tonj
17,100 (4,100)
1,130 (270)
876,000 (210,000)
90,500 (21,700)
4,220 (1,010)
560
12,500 (3,000)
Percent Recycled
93
0
0
0
0
Most of the cooling water is recycled. The waste treatment
methods used on the effluent stream, which consist of
neutralization, precipitation and settling of heavy metal salts
prior to discharge, are shown below. Figures 59 and 60 show the
treatment processing at plant 009.
Treatment
stream, No.
1
2
source
TiC14 precipitation
cooling
Neutralization,
settling
Neutralization,
settling
Table 32 shows the plant 009 effluents after neutralization and
settling treatment. The effluent consists of a neutral pH stream
containing dissolved salts (mostly sodium chloride) and low heavy
metals concentrations. Table 33 s^ows verification measurements
at this facility.
168
-------
STORM DRAINAGE
RETENTION
BASIN
TICI4
WASTE -
STREAM
Ti02
PROCESS
WASTE
STREAM
CaO
1
SUMP PUMP
3 STAGE
NEUTRALIZATION
SYSTEM
FLOCCULENTS-
SUMP PUMP
CLARIF1ER
ALSO SURGE FOR
STORM WATER
RUN-OFF
UNDERFLOW
THICKENER
POLISHING
POND
TiCI4
r>PORTION
OUTFALL
POLISHING
POND
UNDERFLOW
ROTARY
FILTERS
FILTER CAKE TO
LAND STORAGE
FIGURE 99
TREATMENT, TITANIUM TETRACHLORIDE
OF PLANT 009
169
-------
CM
UJ
Q.O
4
WtSTE STREAM-
MOSTLY COOLING WATER
^
STORM
DRAINAGE
SYSTEM
V
RETENTION
BASIN
SUMP
PIMP
V
SUMP
PUMP
ALL WATER GOES THRU
SUMP PUMPS
SETTLING
POND
SETTLING
POND
SETTLING
POND
SETTLING
POND
->OUTFALL
(SEPARATE
FROM TiCl4
; TREATMENT)
FIGURE 60
TREATMENT, TITANIUM DIOXIDE PORTION OF PLANT 009
-------
TABLE 32. Composition of Plant 009 Effluent streams
After Treatment
Parameter*
Suspended Solids
Total Dissolved Solids
COD
PH
Temperature, °C
Stream No. 1
Ran<
Stream No. 2
Average Range
18
3300
50
7.8
16
Organics
Turbidity (Jackson Units) 20
Color (APHA Units) 10
Chloride 1650
Sulfate
Sulfate
Iron 0.2
Copper 0.015
Chromate 0.01
Total Chromium 0.05
Arsenic 0.02
Mercury 0.001
Lead 0.14
*mg/l unless otherwise specified
1-50
1500-4500
40-90
6.0-9.0
7-27
None were
10-80
10-20
750-2050
1-2.5
--
0-3.0
0.01-0.03
0.01-0.15
0.1-0.19
15
300
20
6.8
16
found
20
10
50
—
150
0.2
0.015
0.01
0.05
0.02
0.001
0.02
0-40
180-900
5-45
6.0-9.0
2-32
(Ambient Temp.)
10-50
10-20
70-100
1-2.5
90-450
0.1-1.0
0.01-0.03
0.01-0.15
0.02
171
-------
TABLE 33. Verification Data of Plant 009
Parameter*
Flow, cu m/day (MGD)
Temperature, °C
Color (APHA Units)
Turbidity (FTU)
Conductivity
Suspended Solids
PH
Acidity: Total
Free
Alkalinity (Total) P
T
Hardness: Total
Calcium
Halogens: chlorine
Chloride
Fluoride
Sulfate
Phosphates (Tota1)
Nitrogen (Total)
Heavy Metals:
Iron
Chromate
Oxygen (Dissolved)
Lake
Intake Water
Effluent
Stream ttl
Effluent
Stream *2
3650 (0.964)
9
100
35
100 (NaCl)
25.0
7.9
N/A
N/A
0 (CaC03)
93 (CaC03)
129 (CaCO3)
97 (CaC03)
0
36.5
0
32.0
1.4
0.24
6060 (1.60)
16
140
35
2100 (NaCl)
10
7.6
N/A
0 (CaC03)
22 (CaC03)
2600 (CaC03)
1920 (CaC03)
0
2250
0.3
240
0.025
0.14
2240 (0.590)
26.5
90
30
170 (NaCl)
30
6.85
0 (CaC03)
0 (CaCO3)
0 (CaC03)
28 (CaC03)
185 (CaC03)
139 (CaC03)
0
49.5
0.25
175
0.225
1.3
0.225
0 (Cr+6)
10.8
1.6
0 (Cr+6)
9.0
0.4
0 (Cr+6)
6.2
*mg/l unless otherwise specified
172
-------
b) Sulfate process
For the sulfate process, we have examined information on all the
existing facilities in the United states. The following
description lists the raw wastes and waste segregation practices
normally used by the industry and describes planned improved
treatments.
In the sulfate process, ground ilmenite ore is digested with
concentrated sulfuric acid at relatively high temperature. The
acid used is normally about 150 percent of the weight of the ore.
In some cases, small amounts of antimony trioxide are also added.
The resulting sulfates of titanium and iron are then leached from
the reaction mass with water, and any ferric salts present are
then reduced to ferrous by treatment with iron scrap to prevent
coloration of the final titanium dioxide product.
After these operations, the resulting solutions are clarified,
cooled and sent to a vacuum crystallizer. There, ferrous sulfate
crystallizes out and is then separated from the mother liquor by
centrifugation. This material is either sold or disposed of as a
solid waste.
The mother liquor is then clarified by filtration after addition
of filter aid and is further concentrated by vacuum evaporation.
Seed crystals or other nucleating agents are added, and the con-
centrated liquor is then treated with steam to hydrolyze the
titanyl sufate present. The resulting precipitate is collected
by filtration, washed several times and then calcined to yield
titanium dioxide. The calcined product is ground, quenched and
dispersed in water. The coarse products are separated in a
thickener to which caustic soda is added to maintain a constant
pH. These coarse particles are reground and further processed to
yield a purer product.
Table 34 gives a generalized listing of the raw wastes from
titanium dioxide manufacture by the sulfate process. Data in
this table are in a form applicable to the effluent from any of
the five existing sulfate process plants. Each of these five
facilities have slightly different raw wastes due to differences
in compositions of the raw ores. Table 35 lists typical ores
used in U.S., manufacture of titania, with the Adirondack and
Austrailian Ilmenites being typical of ores used with the sulfate
process.
Discussion of water use and treatment will be based on one
facility, chosen from the five plants. The specific facility
used for this modeling discussion is plant 122. A general waste
treatment flow chart for this facility is presented in Figure 61
and generalized water usage is:
173
-------
SULFURIC ACID-i
p-TITANIUM BEARING ORE
DIGESTION
SETTLING
EXCESS TO
STOCKPILE
A
CLARIFICATION
IRON REMOVAL
SALE
COPPERAS
A'
PRECIPITATION
AND SOLIDS
SEPARATION
_v
WASHING
CALCINATION
Ti02 DUST
WET TREATMENT
FILTRATION
AND
WASHING
A''
DRYING
AND
GRINDING
CHLORIDE .
PROCESS—^
WASTE
STREAM
T102 PIGMENT PACKING
FIGURE 61
SULFATE PROCESS FLOW DIAGRAM
AT PLANT 122
176
-------
Type
Coding
Cooling
Process
Boiler feed
cu m/kkg of Product (gal/ton)
284 (68,000) brackish
83.6 (20,000) fresh
100 (24,000)
16.7 (4,000)
Recycle
0 percent
90 percent
2 percent
30 percent
Currently, all of the process water used is fed to a settling
pond to remove suspended materials and is then discharged. The
process water discharged is from two streams, one from a solids
separation part of the process which contains strong (18-22
percent) acid and a second weak acid stream coming from other
parts of the process. Both streams are currently mixed before
treatment.
In the treatment of wastes, the best approach would be to seg-
regate these two streams and attempt to recover acid values
and/or ferrous sulfate from the more acidic stream, while apply-
ing neutralization procedures to the other. Considering the
strong acid stream first, a possible recovery treatment is first
to partially evaporate the waste to effect further precipitation
of ferrous sulfate and other metal salts which could be recovered
by filtration after cooling. The remaining solution could be
further concentrated for other use or recycled to the process.
The weak acid stream, which does not contain sufficient metal or
acid values to justify recovery, would be oxidized to convert
ferrous salts to the ferric state and then treated with lime to
precipitate heavy metals and adjust for pH to contain about 2000
mg/1 dissolved CaCO3.
One advantage to this scheme is the possibility of further pro-
cessing the heavy metal salts recovered by acid concentration.
These could possibly be further processed to recover vanadium
values, among others. It may be noted that the above-mentioned
scheme is a combination of two treatment approaches. The method
involving total neutralization and settling is currently being
installed at the plant 122 to treat all of the waste streams.
Table 36 lists some information on this treatment process.
Effluents from four titanium dioxide sulfate process facilities
are listed in Table 37. None of these have discharge pH's in the
6.0-9.0 range for all streams, and all contain 3000 mg/1
dissolved solids. In some cases, strong acid streams are
currently segregated and this material, in one case, is disposed
of by ocean dumping. The neutralization procedure, along with a
possible scheme for some acid recovery was discussed earlier in
this section.
For the sulfate process, an alternate treatment may consist of
raw ore enrichment to remove much of the iron present before the
raw material is used in the process. One such potential process
177
-------
TABLE 36 . Future Treatment at Plant 122
Methods
Neutralization of acid
to CaSOU. and oxidation
of iron, and remove
for sale or stockpile
(as ferrous sulfate)
of process wastes and
cooling water
Additional settling
ponds for cooling
waters
Estimated
Installation
Time .
22 mos
22 mos
Estimated
Performance
Reduce C.O.D to Nil
Reduce acidity to Nil
Reduce Fe, Mn, V,
and Cr tp Nil
TDS 50 mg/1
Reduction of suspended
solids formed due to
neutralization by 95*
178
-------
TABLE 37- Partial Discharge Data from TiO2 Sulfate Plants(1)
Plant 142
Streams
Paramater* No.1 No.;
(3) Plant 122 '
Streams
3 No-,_i N0i_2 N0i_3
BODS
COD
pH
Alkalinity
10
71
8.0
220
3
145
1.2
Total Dis- 1660 22,371 15,316
solved
Solids
Plant 046 Streams
°^._i I32i_l No^
6 3
6.5 5.6
21,300 14,000 15,400 3,000 2,700
_*.
—
—
— —
287
1.0
0.3
42
2.6
0.5
27
5.0
Plant
008
No. 1
5 min
5,000
Iron
Sulfate
Chloride
Acidity
Flow,
cu m/day
(MGD)
0.02
1,170
51.5
,_
823
12,377
105
11,435
10,200Combined
(2.7)
—
0.5
1,617
6,394
36
20,000
(5.5)
1,
7,
123,
(32
1.7
378
900
—
400
.6)
31,000
131,000
—
—
6,100
(1.6)
1,000
6,800
625
20,000
20,000
(5.5)
2,
40,
(10
45
187
480
160
900
.8)
15
125
2,830
1000
30,300
(8.0)
100
—
—
—
(1)
(2)
One plant of one manufacturer is not listed here.
and chromate concentrations were provided.
Data on titanium dioxid
The corporation owning this facility is currently developing a process
for recovery and recycle of the sulfuric acid used. This process is
still under testing on the pilot plant scale.
(3) This plant barges its strong acid wastes out to sea for disposal. This
method of disposal of highly acid wastes containing large amounts of
dissolved heavy metals is not considered satisfactory. Effluent No. 3
is the available data on material dumped at sea.
*mg/l unless otherwise specified
17,9
-------
under development at the U.S. Bureau of Mines Reno Research
Center involves the smelting of ilmenite (FeTiO3) with coal and
sodium borate-titanate slag which .contains HO weight percent
titanium dioxide and 0.2 weight percent iron. Over 99 percent of
the titanium in the ore is recovered in the slag, while about 90
percent of the iron present is converted to the elemental form.
After separation of the iron from the slag, air or oxygen is
blown into the molten slag to oxidize the titanium to the
tetravalent form which is readily soluble in acid. The molten
slag is water quenched and leached in hot water to yield a sodium
titanate residue (70 - 90 weight percent TiO2) in a sodium torate
solution. The recovered titanate can then be used in the sulfate
process.
Sodium borate in solution is recovered by crystallization and can
te recycled to the smelting step. Use of this procedure to pro-
vide a sodium titanate feed for the sulfate process eliminates
the generation of large amounts of iron sulfate and the inherent
problems related to its disposal.
Other methods of ore enrichment under development have been
alluded to by the various sulfate process titanium dioxide
producers, but details have not been made available.
Substitution of sodium titanate for ilmenite as a sulfate process
raw material would lead to a sulfate - bisulfate by-product which
could be recovered by crystallization (as is done with ferrous
sulfate) for sale. This would eliminate much of the heavy metal
salt discharge problems with the sulfate process and also solve
the prcblem of acidic discharges via recovery of a low grade
sodium bisulfate by-product for sale or other use.
This approach may prove to be.a superior approach to either the
neutralization scheme or the acid recovery techniques mentioned
earlier. The economics of the above mentioned possible sulfate
process modification have not yet been reported. A more detailed
evaluation of this possible process must await such an economic
presentation.
VERIFICATION SAMPLING AND ANALYTICAL METHODS
Sampling Operations
Two teams of two men each were assigned to the field sampling and
measurements operations. Each of the teams was equipped with a
station wagon and a 4.7-meter trailer Outfitted as a mobile water
testing laboratory. The visit of a team to each facility was
preceded by a visit to the plant by one of the senior engineers
on the project team. During this visit, effluent streams and
potential sampling sites were determined and approximate expected
stream compositions were established.
180
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The duties of the field team visiting the plant included mea-
surement of flow rate and collection of samples at each desig-
nated sampling site. Methods used to determine flow rates varied
from stream to stream, but included: (1) Use of existing weirs or
installed flow meters; (2) Use of current meter plus dimensional
measurements; (3) Direct collection of small outfall streams,
with volumetric measurement related to duration of .collection;
(4) Use of dye tracer to give velocity measurement (plus
dimensional measurements).
Since many of the streams of interest could not be approached,
the wastes contained therein were sampled after having mixed with
one or more other streams.
Fcr most effluent sampling sites, four one-liter samples were
taken (one per hour) over a four-hour duration. These samples
were then mixed to give a four-liter composite sample. One four-
liter grab sample was taken of the water supply tc the plant. At
the end of the day, a four-liter grab sample was taken at each
sampling site (and of the water supply) for backup.
One-half of the four-liter composite sample was Used for analyses
and tests in the field laboratory. The remaining two liters of
composite sample were divided into several samples, some of which
were acid-stabilized and transported to an analytical lat for
further testing. The sample was split with the plant where it
was collected when requested by plant personnel.
The results obtained by the use of the field transportable test
methods were, in general, quite reliable. As a routine matter,
however, standard test samples were inserted into the analytical
program to allow some estimate of the validity of the results
reported from the field. The unlabeled standard samples were
made up from EPA Reference Samples and presented to the
analytical personnel without obvious identification.
The analysis of the samples from various process and discharge
streams has been a somewhat complex procedure. This is due,
primarily, to the extraordinary variation in flow rates, con-
centration of solutes and (in particular) the extremely wide
range of suspended solids which was encountered,
Pretreatments in the field for the various types of samples were;
(1) Suspended and dissolved solids •* none;
(2) Metal ion analysis - addition of 5 ml of concentrated nitric
acid per liter of sample;
(3) COD analysis - used immediately in the dichromate reflux
apparatus or treated with 1.0 N sulfuric acid;
(4) Nitrogen analysis - used immediately or treated with mercuric
chloride for stabilization;
181
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<5) Phosphorus - addition of UO ing; of mercuric chloride per
liter; and /
(6) Fluoride - none*
The analytical methods used are those described in EPA's Methods
for Chemical An.Sl¥Si§ 2f SJStSI dM Wftfitfigj. i21ii
182
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SECTION VI
SELECTION OF POLLUTANT PARAMETERS
.'.waste water characterization detailed in the previous section
has been reviewed to determine what waste water constituents are
present in significant quantities from the various product
sutcategories. The criterion used in the selection of pollutant
parameters for each subcategory include:
a) Sufficient data is available with regard to the
quantities of a pollutant in the raw waste load as well
as its treatability by various waste water treatment
systems.
b) The pollutant is generally present in the raw waste load
in quantities sufficient to cause deletrious effects on
the environment.
c) There is demonstrated technology to practicably and
economically reduce the concentration of the pollutant.
The following is a discussion of those pollutant parameters which
have been selected as the subject of effluent limitations. They
have only been selected for those chemical subcategories in which
they are generally present in significant quantities.
ES
The term pH is a logarithmic expression of the concentration of
hydrogen ions. At a pH of 7, the hydrogen and hydroxyl ion
concentrations are essentially equal and the water is neutral.
Lower pH values indicate acidity while higher values indicate
alkalinity. The relationship between pH and acidity or
alkalinity is not necessarily linear or direct.
Waters with a pH below 6.0 are corrosive to water works
structures, distribution lines, and household plumbing fixtures
and can thus add such constituents to drinking water as iron,
copper, zinc, cadmium and lead. The hydrogen ion 'concentration
can affect the "taste" of the water. At a low pH water tastes
"sour". The bactericidal effect of chlorine is weakened as the
pH increases, and it is advantageous to keep the pH close to 7.
This is very significant for providing safe drinking water.
Extremes of pH or rapid pH changes can exert stress conditions or
kill aquatic life outright. Dead fish, associated algal blooms,
and foul stenches are aesthetic liabilities of any waterway.
Even moderate changes from "acceptable" criteria limits of pH are
deleterious to some species. The relative toxicity to aquatic
life of many materials is increased by changes in the water pH.
Metalocyanide complexes can increase a thousand-fold in tcxicity
with a drop of 1.5 pH units. The availability of many nutrient
183
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substances varies with the alkalinity and
more lethal with a higher pH.
acidity. Ammonia is
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.
Total Suspended solids
Suspended solids include both organic and inorganic materials.
The inorganic components include sand, silt, and clay. The
organic fraction includes such materials as grease, oil, tar,
animal and vegetable fats, vdrious fibers, sawdust, hair, and
various materials from sewers. These solids may settle out
rapidly and bottom deposits are often a mixture of both organic
and inorganic solids. They adversely affect fisheries by
covering the bottom of the stream or lake with a blanket of
material that destroys the fish-food bottom fauna or the spawning
ground of fish. Deposits containing organic materials may
deplete bottom oxygen .supplies and produce hydrogen sulfide,
carbon dioxide, methane, and other noxious gases.
In raw water sources for domestic use, state and regional
agencies generally specify that suspended solids in streams shall
not be present in sufficient concentration to be objectionable or
to interfere with normal treatment processes. suspended solids
in water may interfere with many industrial processes, and cause
foaming in boilers, or encrustations on equipment exposed to
water, especially as the temperature rises. Suspended solids are
undesirable in water for textile industries; paper and pulp;
beverages; dairy products; laundries; dyeing; photography;
cooling systems, and power plants. Suspended particles also
serve as a transport mechanism for pesticides and other
substances which are readily sorbed into or onto clay particles.
Solids may be suspended in water for a time, and then settle to
the bed of the stream or lake. These settleable solids
discharged with man's wastes may be inert, slowly biodegradable
materials, or rapidly decomposable substances. While in
suspension, they increase the turbidity of the water, reduce
light penetration and impair the photosynthetic activity of
aquatic plants.
solids in suspension are aesthetically displeasing. When they
settle to form sludge deposits on the stream or lake bed, they
are often much more damaging to the life in water, and they
retain the capacity to displease the senses. solids, when
transformed to sludge deposits, may do a variety of damaging
things, including blanketing the stream or lake bed and thereby
destroying the living spaces for those benthic organisms that
would otherwise occupy the habitat. When of an organic and
184
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therefore decomposable nature, solids use a portion or all of the
dissolved oxygen available in the area. Organic materials also
serve as a seemingly inexhaustible food source for sludgeworms
and associated organisms.
Turbidity is principally a measure of the light absorbing
properties of suspended solids. It is frequently used as a
substitute method of quickly estimating the total suspended
solids When the concentration is relatively low.
Cyanide
Cyanides in water derive their toxicity primarily from
undissolved hydrogen cyanide (HCN) rather than from the cyanide
ion (CN~). HCtt dissociates in water into H+ and CN~ in a pH-
dependent reaction. At a pH of 7 or below, less than 1 percent
of the cyanide is present as CN~; at a pH of 8, 6.7 percent; at a
pH of 9, 42 percent; and at a pH of 10, 87 percent of the cyanide
is dissociated. The toxicity of cyanides is also increased by
increases in temperature and reductions in oxygen tensions. A
temperature rise of 10°C produced a two- to three-fold increase
in the rate of the lethal action of cyanide.
Cyanide has been shown to be poisonous to humans, and amounts
over 18 mg/1 can have adverse effects. A single dose of 6 mg/1,
about 50-60 nig, is reported to be fatal.
Trout and other aquatic organisms are extremely sensitive to
cyanide. Amounts as small as 0.1 mg/1 can kill them. Certain
metals, such as nickel, may complex with cyanide to reduce
lethality especially at higher £H values, but zinc and cadmium
cyanide complexes are exceedingly toxic,
When fish are poisoned by cyanide, the gills become considerably
brighter in color than those of normal fish, owing to the
inhibition by cyanide of the oxidase responsible for oxygen
transfer from the blood to the tissues.
Chromium
Chromium, in its various valence states, is hazardous to man. It
can produce lung tumors when inhaled and induces skin
sensitizations. Large doses of chromates have corrosive effects
on the intestinal tract and can cause inflammation of the
kidneys. Levels of chromate ions that have no effect on man
appear to be so low as to prohibit determination to date.
The toxicity of chromium salts toward aquatic life varies widely
with the species, temperature, pH, valence of the chromium, and
synergistic or antagonistic effects, especially that of hardness.
Fish are relatively tolerant of chromium salts, but fish food
185
-------
organisms
sensitive.
and other lower forms of aquatic life are extremely
Chromium also inhibits the growth of algae.
In some agricultural crops, chromium can cause reduced growth or
death of the crop. Adverse effects of low concentrations of
chromium on corn, tobacco and sugar beets have been documented.
Chemical Oxygen Demand
Certain waste water components are subject to aerobic biochemical
degradation in the receiving stream. The chemical oxygen demand
is a gross measurement of organic and inorganic material as well
as other oxygen-demanding material which could be detrimental to
the oxygen content of the receiving water.
Iron
The presence of iron in water causes taste and turbidity
problems. It has been shown to be harmful to fish and plants in
varying concentrations. Ferric hydroxide has been known to cause
detrimental effects to plankton.
Lead
The presence of lead may be a problem in receiving waters.
Various oysters and lobsters are known to be adversely effected
when exposed to lead in concentrations less than 0.5 mg/1. Lead
poisoning in humans has been reported to have been caused by
drinking water containing less than 0.1 mg/1 lead.
Mercury
*™ ^™-*-«^^»^—*fc
Mercury has been shown to be deletrious to the environment in low
concentrations. Many aguatic organisms are adversely affected by
mercury concentrations of less than 0.01 mg/1.
Total Organic Carbon
Soluble organics may cause utilization or depletion of dissolved
oxygen by the activity of aerobic bacteria. They may also impart
undesirable tastes and odors to a water supply. For example,
phenolics are a special nuisance in drinking water supply,
particularly after chlorination, because of the very low
concentrations (less than 0.002 mg/1) which result in taste and
odor detection,
The quantity of soluble organics can be measured as BOD, COD or
TOC (Total Organic Carbon). However, each of these parameters
will measure differing amounts of soluble organics. For example,
many organic compounds which are dichromate oxidizable (COD) are
not biochemically oxidizable (BOD). Also, many inorganic
substances such as sulfides, nitrites, etc., are oxidized by
186
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dichromate (COD) which may be misleading when estimating the
organic content of the waste water. The total organic carbon
determination oxidizes the carbon atoms of organic molecules to
carbon dioxide, and measures the amount of carbon dioxide
quantitatively. It lacks the many variables present in the COD
and BOD analyses, resulting in more reliable and reproducible
results for organic determinations.
In general, other pollutant parameters have not been selected
because they are present in relatively small quantities. There
are a few notable exceptions, however. Dissolved salts, such as
chlorides and sulfates, are often present in large quantities.
Treatment technologies to reduce or remove these constituents may
be expensive and in many cases the costs are prohibitive at this
time.
Titanium dioxide manufacture generates a waste stream containing
many types of metal ions. Treatment and removal of iron will
coincidently remove other metals to acceptable levels.
Therefore, other waste water constituents have not been the
subject of effluent guidelines, even though they may be present
in large quantities.
187
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SECTION VII
CONTROL AND TREATMENT TECHNOLOGY
Alternative control and treatment technologies for each chemical
sutcategory are discussed in detail on the following pages.
SPECIFIC CONTROL AND TREATMENT PRACTICES IN THE INDUSTRY
Aluminum Chloride
Direct chlorination of aluminum to produce aluminum chloride is a
relatively simple process. Plants are small (9 to 18 metric
tons/day). There is no process water involved, nor usually any
ceding water. The only source of water wastes is from equipment
used to treat air-borne wastes such as aluminum chloride dust
around the packing station and aluminum chloride and chlorine
from the air-cooled condensers.
In some plants, run on the aluminum-rich side (white or gray
aluminum chloride), there is very little chlorine in the dis-
charge from the air-cooled condenser. Also, the gas volume from
the condenser is such that only a very small quantity of aluminum
chloride is discharged. In such plants there may be no air
pollution control provision. One exemplary plant operates in
this fashion. In plants operating on the chlorine-rich side
(yellow aluminum chloride), water scrubbing of the air condenser
discharge gases is needed.
At least three practicable, economically feasible, and low energy
air pollution control approaches are available:
(1) No air or gas treatment for gray or white aluminum chloride.
(2) Gas scrubbing and sale of scrubber wastes. This approach is
taken by an exemplary plant of this study,
(3) Gas scrubbing followed by chemical treatment to precipitate
aluminum hydroxide and convert chlorine to sodium chloride.
Technology available from the chlor-alkali and titanium dioxide
chloride process may be applied.
Aluminum sulfate
Current typical treatment involves use of a settling pond to
remove muds followed by neutralization of residual sulfuric acid
prior tc discharge.
Two exemplary plants (049 and 063) have closed loop waste-water
systems. Suspended solids are removed in settling vessels and
ponds and the clear overflow is returned to the manufacturing
process.
189
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TABLE 38. Summary of BPCTCA and BATEA
Chemical
BPCTCA
Guideline
Best Practicable Control
Technology Currently Available
BPCTCA
BATEA
Guideline
Best Available Technology
Economically
Achievable
BATEA
Aluminum
Chloride
(Anhydrous)
Aluminum
Sulfate
Calcium
Carbide
Hydrochloric
Acid
Chlorine
Burning
Hydrofluoric
Acid
Sodium
Bicarbonate
No discharge of
pollutants in
process waste
waters
No discharge of
pollutants in
process waste
waters
No discharge of
pollutants in
process waste
waters
No discharge of
pollutants in
process waste
water
No discharge of
pollutants in
process waste
waters
No discharge of
pollutant's In
process waste
water
(1) No water scrubbers for white or Some as BPCTCA
grey aluminum chloride production
(2) For yellow aluminum chloride pro-
duction, gas scrubbing and sale of
scrubber wastes as aluminum chloride
solution; or
(3) Gas scrubbing followed by chemical
treatment to precipitate aluminum
hydroxide and and recycle
(1) Settling pond and reuse Some as BPCTCA
(1) Dry dust collection system Same as BPCTCA
(1} Acid containment and isolation with Same as BPCTCA
centralized collection of acid wastes;
and reuse
Some os BPCTCA
(1) Acid containment and isolation;
and reuse
Some as BPCTCA
(1) Evaporation and product recovery; Some as BPCTCA
or
(2) Recycle to process;
Same as BPCTCA
Same as BPCTCA
Some as BPCTCA
Same os BPCTCA
Same as BPCTCA
Sodium
Chloride
(Solar
Process)
Sodium
Silicate
Return of unused
salts to the
brine source
TSS 0.005
(1) Good housekeeping to prevent
contamination of waste salts
Same as BPCTCA
m Cl i ^ • .- No discharge of
(1) Storage of wastes in an evaporation - ] utants ^ n
P0^'' or process waste
(2) Ponding and clarification water
Same as BPCTCA
Ponding or clarification
and recycle of the
treated waste water
Sulfur!c Acid
(Sulfur Burning
Contact Process)
No discharge of
pollutants In
process waste
water
(1) Acid containment and isolation
with recycle to process or sale
os weak acid;
Same as BPCTCA
Same as BPCTCA
(continued on next page)
190
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TABLE 38. Summary of BPCTCA and BATEA (continued)
Best Available Technology
Chemical
Lime
Nitric Acid
Potassium
(Metal)
Potassium
Dichromate
Potassium
Sulfate
BPCTCA
Guideline
No discharge of
pollutants in
process waste
water
No discharge of
pollutants in
process waste
water
No discharge of
pollutants In
process waste
water
No discharge of
pollutants in
process waste
water
No discharge of
pollutants in
process waste
water
Flow Limitation
Best Practicable Control
Technology Currently Available
BPCTCA
(1) Dry Bag Collection System; or
(2) Treatment of scrubber water by
ponding and clarification
and recycle
(1) Acid containment and isolation
and reuse
(1) No process water used in manu-
facture
(1) Replacement of barometric con-
densers with non-contact heat
exchangers; recycle of process
liquor
(1) Evaporation of brine waters with
recovery of magnesium chlorine;
or
(2) Reuse of brine solution in process
in place of process water;
BATEA
Guideline
Same as BPCTCA
Same as BPCTCA
Same as BPCTCA
Same as BPCTCA.
Same as BPCTCA
economically
Achievable
BATEA
Same as BPCTCA
Same as BPCTCA
Same as BPCTCA
Same as BPCTCA
Same as BPCTCA
Flow Limitation
1 i ters/kkg kg/tckg
Calcium
Chloride
(Brine
Extraction)
Hydrogen
Peroxide
(Organic)
Sodium
(Metal)
Sodium
Chloride
(Solution
Mining)
Sodium
Sulfite
Soda Ash
(Sodium
Carbonate)
Solvay Process
TSS Other
330 0.0082 -
16,000 0.40 0.22
TOC
9,000 0.23
6,400 0.15
630 0.016 1.7**
COD
(As C^C
6,900 0.17
- (1) Settling pond or clarification
(1) Isolation and containment of
process wastes; oil separation
and clarification
(1) Settling pond; and
(2) Partial recycle of brine waste
solution after treatment
(1) Containment and isolation of
spills, packaging wastes.
scrubbers, etc; partial recycle
to brine cavity
(1) Air oxidation of sodium sulfite
wastes to sodium sulfafe — 94%
'7 effective; and final filtration to
remove suspended solids
(1) Settling ponds
1 iters/kkg kg/
TSS
No discharge of
pollutants In
process waste
water
No discharge of
pollutants In
process waste
water
No discharge of
pollutants in
process waste
water
No discharge of
pollutants in
process waste
water
No discharge of
pollutants in
process waste
water
6,900 0.10
l^kg
Same as BPCTCA plus
(1) Replacement of barometric con-
densers with noncontact heat ex-
changers; and additional recycle
(1) Chemical decomposition for per-
oxide removal
(2) Carbon adsorption for organic
removal
100% brine recycle and reuse or sale
of spent sulfuric acid
Same as BPCTCA plus
(1) Replacement of barometric con-
densers with noncontact heat
exchangers
Same as BPCTCA plus recovery of
waste sodium sulfate
(1) Settling ponds and clarification
191
(coatineed on next page)
-------
TABLE 38. Summary of BPCTCA and BATEA (continued)
Chemical
Best Practicable Control
BPCTCA Technology Currently Available
Guide! ine BPCTCA
BATEA
Guideline
Best Available Technology
Economically
Achievable
8ATEA
Flow Limitation
TSS Other
Hydrogen
Peroxide
(Electrolytic)
95 0.0025 0.002 (1) Ion exchange to convert sodium No discharge of
CN~ ferrocyanide to ammonium
ferrocyanide which is then re-
acted with hypo chlorite solution
to oxidize it to cyonote sofu-
tions; and
(2) Settling pond or filtration to
remove catalyst and suspended
solids
pollutants in
process waste
water
(1} Same as BPCTCA plus segregation
of waste water from cooling
water and evaporation of the waste
stream and recycle of the dis-
tillate
Sodium 8,900 0.22 0.0005 (1) Isolation and containment of
Dichromate Cr+o spills, leaks, and runn off; and
and 0.0044 (2) Batch wise treatment to reduce
Sodium Cr(total) hexovalent chromium to trivalent
Sulfate chromium with NaHS, plus pre-
cipitation with lime or caustic;
and
(3) Settling pond with controlled
discharge
Chlor-aikali 3,300 0.32 0.0025 (1) Asbestos and cell rebuild
(Diaphragm Pb wastes are filtered or
Cell) settled in ponds then land
dumped; and
(2) Chlorinated organic wastes
are incinerated or land
dumped; and
(3) Purification muds from brine
purification are turned to
salt cavity or sent to
evaporation pond/settling
pond; and
(4) Weak Caustic—brine solu-
tion from the caustic filters
is partially recycled
Chlor-alkali 21,000 0.32 0.00014 (1) Cell rebuilding wastes are
(Mercury Hg filtered or placed in settling
Cell) pond, then used for landfill;
and
(2) Chlorindated organic wastes
are incinerated or placed in
containers and land dumped;
and
(3) Purification muds from brine
purification are returned to
brine cavity or sent to
evaporation/settling ponds;
and
(4) Partial recycle of brine waste
streams; arid
(5) Recovery and reuse of mercury
effluent by curbing, insolation
and collection of mercury con-
taining streams, then treatment
with sodium sulfide
No discharge of
pollutants In
process waste
water
No discharge of
pollutants in
process waste
waster
No discharge of
pollutants in
process waste
water
Same as BPCTCA plus
(1) Evaporation of the settling
pond effluent with recycle
of water and land disposal or
recovery of solid waste
Same as BPCTCA plus
(1) Reuse or sell waste sulfuric
acid
(2) Catalytic treatment of the
hypochlorite waste and reuse
or recovery
(3) Recycle of all weak brine
solutions
(4) Conversion to stable anodes
Same as BPCTCA plus
(1} Reuse or recovery of waste
sulfuric acid
(2) Catalytic treatment of the
hypochlorite waste and reuse
or recovery
(3) Recycle of all weak brine
solutions
(continued on next page)
192
-------
TABLE 38. Summary of BPCTCA and BATEA (continued)
Chemical
Titanium
Dioxide
(Chloride
Process)
Titanium
Dioxide
(Sulfate
Process)
BPCTCA Best Practicable Control
Technology Currently Available
Guideline BPCTCA
Flow Limitation
lltersAkg kg/kkg
TSl Other
90,500 2.2 Iron (1) Neutralization with lime or
0.36 caustic; and
(2) Removal of suspended solids
with settling ponds or
clarifier-thickener; and
(3) Recovery of by-products
.g., V, Al, Si, Cr, Mn, Nb & Zr.
210,000 10.5 Iron (1) Neutralization with lime or
0.84 caustic; and
(2) Removal of suspended solids
with settling ponds or clarifier-
thickener; and
(3) Recovery of by-products
Best Available Technology
BATEA Economically
Achievable
Guideline BATEA
TSS Iron
1.3 0.18 Same as BPCTCA plus additional
clarification and polishing
TSS iron Same as BPCTCA plus addition
-5"1 0.42 clarification and polishing
"Monthly average values. To convert from metric units to English units (Ibs/ton), multiply the above values by 2.
"COD of 2720 mg of dlchromate ion per lite*
193
-------
Calcium Carbide
There is no process water involved in the production of calcium
carbide. Ancillary water wastes such as cooling tower blowdowns
and ion exchange regenerants are often present. There may also
be water-borne wastes from air pollution control equipment.
Water-borne wastes from air-borne waste control equipment may be
avoided by use of dry bag collector systems. Unlike aluminum
chloride, the air-borne wastes from the calcium carbide process
are all dusts — coke and coal fines, limestone powder and
calcium carbide from the packing station. Coke, coal and
limestone fines, which constitute a significant fraction of the
feed materials, may be profitably returned to the system. One
plant uses only dry bag collectors and recycles the collected
fines tc the furnace.
Dry bag collection of air-borne fines eliminates waterborne
wastes and makes it possible to reuse these fines. It also
significantly reduces energy requirements by avoiding high energy
drying costs needed for recovery of water wastes.
Calcium Chloride
This chemical is obtained both from soda ash wastes and from
natural salt deposits. The soda ash produces large amounts of
calcium chloride as a by-product. Unreacted sodium chloride and
other dissolved solids are present in this waste stream. After
calcium chloride is extracted from this waste stream, the
remaining calcium chloride, sodium chloride and ether dissolved
solids may be returned to the waste stream of soda ash
manufacture. Extraction of calcium chloride from natural salt
deposits is carried out in a major chemical complex and is
scheduled within the next six months to be brought to virtually a
zero process waste water pollutant discharge. Since both
processes are dissimilar, there are no typical practices. The
two major producers differ widely in their treatment approach.
From the soda ash process, recovery of calcium chloride is con-
sidered as a zero discharge process similar to sodium sulfate
from the sodium dichromate process. There are no additional
wastes generated as a result of this recovery.
The natural salt process, on the other hand, utilizes the in-
tegrated nature of the complex where it is produced to take
advantage of every normal waste. Sodium chloride goes to chlor-
alkali facilities. Magnesium chloride, which is often difficult
to dispose, is isolated and used for other processes. Con-
sequently this process for making calcium chloride also has no
effluent in the particular complex where it is made. This is a
good example of the previously discussed principle that wastes
194
------- An error occurred while trying to OCR this image.
-------
limited use for these waste products. Examples of how waste
conversions can be made in the chlor-alkali process are given in
the following equations:
(1) 2NaCl 3- 2Na + C12
(2) 2Na + 2H2O >* 2NaOH + H2
(3) 2NaOH + C12—>- NaOCl + NaCl + H20
(4) 2NaOCl + Cat.—*- 2NaCl + O2
(5) C12 + H2 >- 2HC1
(6) HC1 + NaOH >- NaCl + H2O
Equations (1) and (2) show the product formations. Equation (3)
represents tail gas scrubbing operations to remove chlorine gas
from air effluents from the plants. Equation (4) shows conver-
sion of sodium hypochlorite back to salt raw reactant materials.
Equation (5) eliminates waste chlorine gas by direct burning of
chlorine to produce hydrochloric acid. Equation (6) uses hydro-
chloric acid to neutralize waste sodium hydroxide, thereby pro-
ducing salt for return to the system. Provided the water-borne
waste streams are kept isolated from much larger cooling water
streams, control and treatment techniques are entirely feasible.
Salt impurities have to be removed by precipitations before the
brine solutions can be used in the cells. Treatment with soda
ash, sodium hydroxide, and sometimes barium chloride, removes
calcium, magnesium and sulfate ions as calcium carbonate, magnes-
ium hydroxides and barium sulfates, respectively. The precipi-
tated muds may be removed in ponds or clarification tanks. The
muds may be disposed of by land dumping or fill.
Brine and sulfuric acid wastes may be neutralized with lime or
sodium hydroxide, and ponded for reduction of suspended solids.
Water-borne mercury in the mercury cell process may be treated
and removed by a variety of processes, usually employing
precipitation of mercury sulfides, followed by mercury recovery
by roasting or chemical treatment processes. Plants with typical
recovery systems reduce mercury in the plant effluent to 0.11 to
0.22 kg/day (0.25-0.50 Ib/day).
Total waste reduction depends on in-process control, isolation,
treatment and reuse. There is no known problem which has not
been solved by at least one plant of this survey.
Mercury cells are inherently "cleaner" processes than the dia-
phragm cells. Diaphragm cells have asbestos diaphragm deterior-
ations with suspended asbestos wastes. These have to be filtered
out or allowed to settle in ponds. Sodium hydroxide produced in
diaphragm cells has sodium chloride and other wastes and has to
be purified for many uses.
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A sodium sulfate purge, made by back-washing the precipitated
salt slurry on the filter during the evaporation concentration of
sodium hydroxide, is also needed to ensure satisfactory diaphragm
cell operation. This sulfate purge can be handled by removing it
from the system and using it elsewhere (as is done by exeirplary
diaphragm cell plant 057), by returning it for sulfate removal in
the brine purification, or by recovery of sodium sulfate for
sale.
Another waste from the diaphragm process, but not the mercury
cell, is organic waste from the graphite anode. These are
currently land disposed by the exemplary diaphragm cell plant,
but are allowed to go out in waste streams at others-
Waste sulfuric acid from the chlorine-drying step may be used for
neutralizations in ether processes, sale, shipment to a regen
sulfuric acid plant' or concentration.
Collected chlorine gas for abatement of air-borne wastes can be
burned to produce hydrochloric acid or converted to sodium
chloride as discussed earlier.
Diaphragm cells are prone to develop cracks around their anode
protective resin seals and lead salts from the underlying lead
mountings can get into the effluents. Metal anodes can eliminate
this problem and at a reported significant reduction in required
cell electrical energy load.
The mercury cell, although "cleaner" than the diaphragm process,
has a major waste problem in the form of mercury in the water-
borne wastes. Major expenditures (discussed quantitatively in
Section VIII) and in-process modifications have been made to
alleviate this problem. Three plants discussed in section V
reduce their mercury discharge to 0.00057, 0,000069 and 0.00007
kg/kkg (0.0011, 0.000137, 0.00014 Ib/ton). A small, 140 ten/day
plant has reportedly reduced its mercury discharge to an average
of 0.000143 kg/kkg (0.000286 Ib/ton). These low levels are
accomplished by isolation of mercury-containing waste strearrs and
chemical treatment of these streams.
Although no specific mention has been made of potassium hydroxide
production, the same principles hold except that potassium is
substituted for sodium.
By employing extensive treatment, control, recycle, and recovery,
the chlor-alkali process may be operated with no discharge of
process waste water pollutants to navigable waters.
Hydrochloric Acid
The only process considered in this study is chlorine burning.
Only about ten percent of the U.S. production comes from this
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process. Most hydrochloric acid is produced as a by-product of
other processes. The chlorine-burning process is a simple one
and capital equipment is relatively inexpensive. The process
fits well with chlor-alkali complexes where lew-cost or waste
chlorine (and possibly hydrogen from mercury cells) is readily
available.
There is no water-borne process waste during normal operation. A
small amount of chlorine and hydrochloric acid wastes is
developed during startup. Neutralization with sodium hydroxide
can be followed by forwarding the neutralized stream to other
chlor-alkali complex uses such as make-up water for brine
solutions used in mercury or diaphragm cells. The size of the
waste load, excluding that from the air-borne hydrogen chloride
treatment, is small - 0.5 to 1.0 kg/kkg.
Since there are no process wastes, spills, leaks, contributions
from air-bcrne hydrogen chloride waste treatment equipment, and
startup and upset wastes are the only concerns. Base treatment
and control of these small miscellaneous wastes consists of
neutralization with available sodium hydroxide followed by
discharge to surface water.
Leaks, spills and startup wastes may be minimized by good
housekeeping, operation, equipment maintenance and production
planning. These wastes are not at this time directly related to
a unit of production and may need to be limited on a case by case
basis. To reduce water-borne wastes, containment and isolation
techniques are required. Dikes, dip pans and other devices are
used to control leaks and spills. Centralized collection and
neutralization with sodium hydroxide can be followed by
forwarding the neutralized stream to other chlor-alkali complex
uses such as make-up water for brine solutions used in mercury or
diaphragm cells. The size of the waste load, excluding that from
the air-borne hydrogen chloride treatment, is small - 0.5 to one
kg/kkg.
Hydrofluoric Acid
Hydrofluoric acid sells for approximately $550/kkg. Therefore,
the incentive for containment and recovery of leaks, spills and
other product losses is understandably greater than for the other
mineral acids. By the nature of the process, large quantities of
cooling water are required. This is in the non-contact category,
however, such that water-borne process waste loads are small.
Neutralization of sulfuric and hydrofluoric acid wastes with
lime, followed by removal of precipitated calcium sulfate and
calcium fluoride in settling ponds, reduces fluorides to 18 mg/1
and calcium sulfate to approximately 2000 mg/1 in treated water
streams.
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Segregation of the leaks, spills and sulfuric acid-containing
wastes from the cooling water reduces the quantity of water which
has to te treated. Also by in-process changes, such as .using
stoichiometric quantities of sulfuric acid in the process
reactor/ the sulfuric acid may be eliminated from the process
waste water stream.
Lime treatment of the isolated wastes and settling pond removal
of the precipitate reduces the fluoride content of this small
stream to approximately 10 mg/1. This procedure gives waste with
less than 0.5 kg total dissolved solids kkg (1 Ib/ton) of
hydrofluoric acid. This treatment makes closed cycle operation
possible.
There are no air pollution problems for this process, but massive
calcium sulfate solid wastes (3400-4250 kg/kkg (6800-8500 Ib/ton)
of hydrofluoric acid) from the process reactor give both land
disposal and rainwater runoff problems. Storage piles of this
calcium sulfate should be located and contained so that materials
such as calcium sulfate and residual lime or sulfuric acid are
not conveyed by rainwater runoff to surface or underground fresh
water streams.
Hydrogen Peroxide
a) Organic process
The organic process effluent generally contains waste hydrogen
peroxide plus organic solvent used in the process. The nature of
this solvent is considered a trade secret.
The hydrogen peroxide waste may be decomposed with scrap iron.
The organic solvent may be removed by skimming the insoluble
layer off the top of the water stream. The effluent may then be
passed into a settling pond for removal of suspended solids or
organic solvent interaction with suspended solids from other pro-
cesses. Additional isolation, containment and treatment of
wastes with scrap iron for peroxides and skimming separation for
organics further reduces the waste loads.
Organics may be removed from this waste water stream by bio-
logical digestion or carbon adsorption treatment.
b) Electrolytic process
The electrolytic process for making hydrogen peroxide is re-
presented by a single U.S. plant (100). Its effluent has
practically the same composition as the incoming water, because
the relatively very small amount of process water discharged is
combined with the very large cooling water stream. Present
levels were accomplished by in-process controls. The total water
flew into the plant is about 41,600 cu m/day or 3,470,00 1/kkg
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(11,000,000 gal/day or 11,000,000 gal/ton). 75.7 cu m/day or
6300 1/kkg (20,000 gal/day or 1830 gal/ton) is treated by ion
exchange and used for boiler feed and process water. Discharges
of this waste include 3.8 cu m/day or 316 1/kkg (1000 gal/day or
92 gal/ton) of ion exchange blowdown, 26.5 cu m/day or 2200 1/kkg
(7000 gal/day or 640 gal/ton) of boiler blowdown and 1.1 cu m/day
or 95 1/kkg (290 gal/day or 27.6 gal/ton) of process water
effluent. This latter stream may be eliminated by simple
procedures such as total evaporation which is economically
feasible because of the small quantity.
Nitric Acid
There are generally no water-borne process wastes. There are
usually no water-borne wastes from air pollution abatement
practices. Cooling water requirements are high. Minor water-
borne wastes are due to leaks, spills and washdowns and ancillary
systems such as cooling towers.
Provisions may be made for handling and neutralizing spills and
leaks. Neutralization can be done with limestone, oyster or clam
shells, lime or sodium hydroxide. Collected leaks, spills and
washdowns may be returned to the process.
Diking of tanks, pump areas, loading and washing areas may be
combined with isolation and reuse of leaks, spills and washdowns.
Diking of large tanks should be sufficient for complete
containment. Emergency ponds should be provided for major
upsets. Limestone or seashell pond linings and ground coverings
may be used for neutralizations.
Potassium Metal
There are no water-fcorne wastes from this process.
Potassium Chromates
Potassium dichromate is made from the reaction of sodium di-
chromate with potassium chloride. There is none of the massive
ore waste present as in the sodium dichromate process. The only
water-borne wastes from the major U.S. production facility
emanate from contamination of once-through cooling water used in
the barometric condensers. These are scheduled for replacement
in 1974 by heat exchangers using non-contact cooling water. This
will result in no discharge of waterborne wastes.
Potassium Sulfate
The exemplary plant for production of potassium sulfate is plant
118. It is a closed cycle plant where water recovery is
accomplished by distillation of 1,500 cu m/day (400 gpd).
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Sodium Bicarbonate
Typical treatment practices involve the settling of suspended
solids in ponds before discharging the effluent to surface
waters.
The untreated effluent from this process is essentially sodium
carbonate in solution. In a complex, use for this solution may
be made, probably at lower cost than for recovery. Present
waterborne wastes are a relatively low 6.5 kg/kkg (13 Ib/tcn) of
product.
By keeping the waste stream small and the solids level high,
evaporative techniques are feasible without undue expense. The
evaporation process yields demineralized water for boilers, plus
recovered product worth $36/kkg ($32/ton). An alternative
approach would involve total recycle.
Sodium Carbonate
The solvay Process for making sodium carbonate (soda ash) is an
old one dating back to the late 1800's. The Solvay plants are
also old, the last U.S. plant being built in the 1930"s.
The solvay Process discharges more poundage of waste into surface
water (solid basis) than any other chemical of this study (sodium
chloride producers deep-well or store most of their effluent).
The only redeeming feature is the relatively low toxicity of the
waste.
Present treatment of water-borne wastes consists of removing most
of the suspended calcium carbonate and other solids in unlined
settling ponds followed by discharge to surface water.
Adjustment for pH may or may not be done prior to this discharge.
The water-borne wastes from the Solvay Process are suspended and
dissolved solids. The suspended solids are removed effectively
by settling ponds and polish filtering can be done, if necessary,
to reduce total suspended solids levels to 25 mg/1.
Dissolved solids are generally present in high concentrations.
There are many treatment technologies available which can be used
to eliminate the dissolved solids from the water effluent.
However, most of them are not economically practical for the
sclvay Process. Also, the geographical location of the plant has
a major bearing on the treatment and disposal feasibility and
costs.
A new plant of the Solvay Process is very unlikely to be consid-
ered. If a new Solvay Process plant were to be built, the
process itself would likely be revised. Process modifications
now in the laboratory or pilot plant stages would have to be
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investigated and developed for commercial feasibility. The major
area of revision would be in the recovery of ammonia from
ammonium chloride. Use and recovery of magnesium hydroxide or
decomposition of ammonium chloride to ammonia and chlorine are
two such modifications that have been proposed. Recovery and
reuse of the excess sodium chloride in the waste effluent could
be accomplished by evaporation and crystallization techniques
similar to those for the salt industry.
Sodium Chloride
Waste disposal is usually accomplished by pumping the brine
wastes back into the well or mine when sodium chloride is made by
the brine extraction process. In the solar evaporation process,
brine wastes are normally returned to the source of the salt
solution. Storage and recovery of magnesium and potassium salts
is technically feasible, but appears uneconomical in most
instances.
Sodium Bichromate and Sodium Sulfate
Typical treatment is to reduce the hexavalent chromium ion in the
waste to trivalent chromium, remove the suspended solids in a
settling pond, and discharge the clear solution to surface water.
Ferrous chloride is often used as a reducing agent.
An exemplary chromium treatment and control plant (184) includes
isolation of all chromium-containing, water-borne wastes from
cooling water, collection of these wastes in tanks, fcatchwise
treatment for hexavalent chromium reduction, and pond settling of
suspended solids. The hexavalent chromium content remaining
after treatment is very low. Provisions are made in this plant
for collection and treatment of rainwater.
Although the treatment and control technologies described above
are excellent for chromium treatment and control, two
environmental problems remain — disposal of large quantities of
solids which gradually fill the settling ponds and discharge of
large quantities of dissolved sodium chloride into surface water.
The settled solids can be landfilled and the sodium chloride can
be recovered by evaporation techniques and sold.
Sodium Metal
Sodium metal is produced in a Downs Cell Process. Chlorine,
produced simultaneously with the sodium, is covered under
chlorine. The treatment and control problems for chlorine, once
it leaves the cell, are the same for the Downs Cell product as
for the mercury and diaphragm cells.
The non-chlorine based wastes consist of brine purification muds,
cell wastes such as bricks, graphite, sodium chloride and calcium
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chloride, and sodium-calcium sludge from the sodium cooling and
purification step. Settling ponds may be used for mud removal.
Bricks, graphite and other solids may be landfilled. Sodium
chloride and calcium chloride may be washed down and allowed to
flew to surface water.
In the exemplary plant of this study, the only cell-
-------
Sulfuric Acid
There are generally no process wastes from the sulfur-burning
sulfuric acid plants. The only water-borne wastes result from
spills, leaks, washdowns, and air-borne sulfur dioxide scrubbers.
Leaks, spills and washdowns may be detected by monitoring pH in-
strumentation. In-process leaks give serious corrosion problems
so that shutdown and repair is in order as soon as these leaks
are detected. Neutralization with lime or sodium hydroxide is
used to control the pH level of the effluent.
Containment, isolation, and reuse or neutralization of minor
leaks, spills and washdowns may be obtained with dikes, catch
pans, sumps and drain systems. Major storage tanks should be
sufficiently diked for complete storage tank capacity contain-
ment. Pond linings and pertinent plant grounds coverings of
limestone or seashells can provide automatic neutralization.
pollution devices to remove sulfur dioxide sometimes contribute
to the water-borne waste load. This may be avoided by utilizing
sulfur dioxide removal processes which do not generate waste
water streams. They should be used for all future installations.
These non-water waste processes include double-absorption add-ons
(for existing plants), and molecular sieve processes. Several
other processes are either in commercial or developmental status.
Existing sulfur dioxide control equipment which invoves water-
borne waste can be converted to a waste-free basis by concern-
tration and recovery of dissolved solids. A sulfuric aci.d plant
in Finland neutralizes its scrubber effluent and concentrates the
salt solution for use as fertilizer feed.
Titanium Dioxide
The titanium dioxide industry is in a state of flux. Rutile is
in a very short supply and most chloride process producers need
this ore or a synthetic version of it. "Synthetic rutiles", or
beneficiated low grade ores, are being offered by various foreign
and a few domestic suppliers. A company in Japan has operated a
27,000 kkg (24.6 ton) plant since 1971 and is expanding to 40,000
kkg (36.4 tons). One D-S. company has announced a proposed
45,000 kkg/yr (41,000 ton/yr) plant using Australian technology.
A comprehensive discussion of ore deposits, their composition,
and beneficiation techniques may be found in Dr. Thomas s.
Mackey1s article "Alteration and Recovery of Ilmenite and
Rutile", Australian Mining, November 1972, pp. 18-94.
a) Chloride process
Waste streams for the chloride process fall into two categories:
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1. Chlorination wastes composed of sludge from titanium
tetrachloride losses and
2. Wastes incurred during the oxidation process and treatment of
titanium dioxide product.
Base level treatment usually includes ponding to remove titanium
dioxide, ore, coke and other settleable solids.
Three techniques for more effective treatment or disposal of
chloride process wastes are available; neutralization of acids
and conversion of metallic chlorides to insoluble oxides, ocean
barging and deep welling.
A full chemical treatment system is used in plant 009. Chemical
neutralization tanks, a clarifier, a thickener, and filters
followed by a pond system are used for full acid neutralization,
conversion and precipitation of metallic oxides, and
concentration of suspended solids into a sludge. The sludge is
disposed of as land fill. Both of the main chloride process
waste streams, Chlorination solids and oxidation process and
titanium dioxide product-treatment wastes, are put through the
chemical treatment system. The water-borne wastes from the
system consist primarily of dissolved calcium chloride.
Deep-welling of the chlorinated wastes is practiced by plant 160.
The oxidation and titanium dioxide product treatment wastes are
sent through a settling pond system and discharged to surface
water. Such deep well disposal is not a general solution to
waste abatement practices, since it is not geologically feasible
in many sections of the country. Ocean barging is also used to
dispose of chloride process wastes, but this method of disposal
is not universally applicable either. Both of these disposal
techniques are subject to stringent permit requirements and must
be consistent with local. State and Federal regulations.
The major chloride process wastes, particularly when low grade
ore is used, are ferrous and ferric chlorides. Various proposals
have been made for disposing of these chlorides. Included in
these proposals are processes for decomposing the iron chlorides
to iron oxide and hydrochloric acid (favored for pickle liquor
recovery), a process for oxidation of iron chlorides to iron
oxides and chlorine, and sale of the iron chlorides as such.
Beneficiation of ore by Chlorination/ separation of iron chlor-
ides, and dechlorination of the iron chlorides is another pro-
cedure. All of the above are still in the exploratory, labora-
tory, pilot plant or other preliminary stage at this time.
Bureau of Mines research is already being carried out.
b) Sulfate process
Approximately 2,000 kg of sulfuric acid and 1,000 kg of metallic
sulfates/kkg of product are discharged from the sulfate process.
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Lew grade ores used in the process contribute major quantities of
metals which may someday be profitably extracted.
Waste streams generated by the sulfate process include:
(1) sludge from the dissolving step and filtration,
(2) copperas,
(3) strong acid cuts,
(4) weak acid cuts, and
(5) titanium dioxide losses.
Wastes may be collected and sent to a settling pond for suspended
solids removal.
Possible treatment and control technologies include filtration
and disposal of the sludge from the dissolving step by land
dumping, neutralization of both strong and weak acid cuts with
limestone, followed by lime treatment to raise the pH to
approximately 8 and' precipitate iron and other metallic oxides
and hydroxides. The conventional chemical treatment system of
neutralization tanks, clarifiers, thickeners, filters or
centrifuges and ponds may be employed for this purpose.
Ocean barging of the strong acid wastes, sludges and metallic
sulfates is now used for disposal by some plants. Uncertainty
about the future of this disposal method currently clouds its
general application. Also, the weak acid and other wastes are
still in many cases being discharged to surface water without
significant treatment.
A pilot New Jersey Zinc Company with contract assistance from EPA
is investigating the feasibility of acid recovery. Acid recovery
is accompanied by treatment of the weak acid, metallic sulfates
and titanium dioxide losses in the same type of chemical
treatment system as discussed for complete neutralization. Acid
recovery reduces the solid waste load inherent with complete neu-
tralization and also decreases the amount of water-borne wastes.
Costs are lower for this approach than for complete
n eutralization.
GENERAL METHODS FOR CONTROL AND TREATMENT PRACTICES IN THE
INDUSTRY
Organic content and biological oxygen demands of the effluents
for inorganic chemical plants are usually very low. Most
alternative control and treatment technologies are well known,
established and extensively practiced in the process of producing
the inorganic chemicals of this study. Practices such as
chemical treatment (neutralization, pH control, precipitation,
and chemical reactions), filtration, centrifuging, ion exchange,
demineralization, evaporation and drying are all standard unit
operations for the industry. Process instrumentation, monitoring
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and control for the chemical industry is outstanding. Another
characteristic of the waste effluents from the inorganic chemical
plants of this study is that they differ widely in both chemical
nature and amount. Table 39 shows typical water-borne waste
loads for the inorganic chemicals included in this study. Soda
Ash (Solvay) and titanium dioxide (sulfate process) have raw
waste loads in excess of the amounts of chemicals produced. On
the other hand, chemicals, such as the mineral acids, calcium
carbide and aluminum chloride, generate almost no water-borne
wastes. Soda ash (Solvay) wastes are neutral salts while
titanium dioxide (sulfate process) wastes are strongly acidic.
Therefore, control and treatment technology has to be applied
differently for each chemical.
Typical control and treatment technology in use on inorganic
waterborne wastes today includes neutralization and pH control on
effluent streams, ponds for settling of suspended solids,
emergency holding, and storage, and discharge of the neutralized
and clarified effluent to surface water.
Discharge of acidic or alkaline wastes to surface water is
uncommon. Harmful wastes such as mercury, arsenic, cyanides,
chromium and other metals are being removed with increasing
efficiency. Technology has been developed for reduction of these
harmful materials to very low levels.
Profitable waste segregations and recoveries, closed cycles, leak
and spill containments, and in-process waste reductions are
demonstrated in the industry. Some of these waste abatement
programs have not involved much money, but most have been
expensive. Numerous plants have reported program costs ranging
from several thousand to several million dollars.
waste abatement for the inorganic chemicals industry may be
accomplished by a variety of methods. These methods may be
divided into control and containment practices and treatment
techniques. In many cases the control and containment practices
are more important than subsequent treatments as far as
feasibility and costs of waste treatment are concerned. The
reasons for this are discussed in the following sections.
In-process controls
Control of the wastes includes in-process abatement measures,
monitoring techniques, safety practices, housekeeping,
containment provisions and segregation practices. Each of these
categories is discussed including the interactions with treatment
techniques.
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TABLE 39. Typical Water-Borne Loads for
Inorganic Chemicals of this Study
Annual
Production
Chemical kkq
Sodium Chloride 39,000,000
Soda Ash (Solvay) 3,630,000
Titanium Dioxide (Sulfate) 374,000
Chloride-(Non-Rutile) 186,000
Chloride (Rutile) 64,000
Chlorine-Sodium Hydroxide 8,600,000
Sodium 150,000
Sulfuric Acid 27,200,000
(Sulfur Burning)
Sodium Bichromate 136,000
Sodium Silicate 601,000
AluminumSulfate 1,020,000
Nitric Acid 6,300,000
Hydrogen Peroxide 64,000
Hydrofluoric Acid 281,000
Sodium Bicarbonate 186,000
Aluminum Chloride 31,000
Sodium Sulfite 209,000
Calcium Carbide 834,000
Hydrochloric Acid 200,000
(Direct Burning)
Waste Load*
kg/kkg Total Waste*
kkg/yr
Product
150
1,500
5,000
400
75
150
150
0.5
58
7.5
3.5
0.25
20
4
4.5
24
3
0.5
0.5
5,850,000
5,440,000
1,870,000
744,000
4,800
1,300,000
22,500
13,600
13,600
4,500
3,570
1,590
1,270
1,120
840
725
625
415
100
NOTES:
1) Production figures were taken from Chenu 5 Eng. News,
May 7, 1973, pp. 8-9 and "The Economics of Clean Water",
Vol. Ill, Inorganic Chemicals Industry Profile, U.S. Dept.
of the Interior, Federal Water Pollution control Admin.,
March, 1970.
2) Typical waste loads were estimated from Final Technical
Report, Contract No. 68-01-0020, Industrial Waste Study
of Inorganic Chemicals, Alkalies and Chlorine, General
Technologies Corp., July 23, 1971 (for EPA).
3) Titanium dioxide industry production figures were esti-
mated from Chem. & Eng. News, February 19, 1973, pp. 8-9.
*Solids basis.
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Raw Materials
Purity of the raw materials used in the manufacturing process
influences the waste load. Inert or unusable components coming
into the process are generally discharged as waste.
Control of these impurities can be exercised in many instances.
Ores can be washedt purified, separated, beneficiated or other-
wise treated to reduce the waste coming into the process. An
important facet of this approach is that this treatment can often
be done at the mining site where such operations can be contained
or handled en the premises. Reduction of shipping charges also
favors beneficiation at the mine. Sometimes, as for "synthetic
rutile" used in the titanium dioxide chloride process,
beneficiated or high quality ore is necessary for developed
process technology. Economics of raw material purity need to be
balanced against the . attendant waste treatment and disposal
costs. As waste costs change, it may become more economical to
use high quality materials.
Although pure raw materials reduce the inherent waste load, there
are instances where, ' aside from economic factors, it may be
desirable to use an impure material. In large manufacturing
complexes, wastes from one process may. be used for useful purpose
in another. This procedure not only eliminates a bothersome
waste from one process, it also gives economic value in the
other. An example is the use of spent sulfuric acid in decomp
plants. Recycled raw materials serve the same desirable
function.
Reactions
Except in rare cases such as the mining of salt or soda ash
(trona), chemical reaction is involved in the manufacture of
inorganic chemicals. Sometimes the reactants are stoichiomet-
rically involved, but more often than not an excess of one or
more of the reactants is used. The purposes of the excess vary
but include:
1. certainty that the more expensive reactants are completely
utilized;
2. yield improvement by driving the reaction in the desired
direction;
.3. safety concerns where it is imperative that a given reactant
be eliminated;
H. shortening reaction time.
Excess reactants must be recovered for recycle or else they
become part of the waste load. Often when the cost of the excess
reactants was small, it had been more economical to let them go
into the waste load rather than recover them. Sodium and calcium
chlorides and sulfates are among the most common materials so
handled.
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Reactions may often be made to operate at more nearly stoi-
chiometric conditions and thereby reduce waste loads. Also, the
waste load may be deliberately changed in many cases by changing
the reactant ratio. In the burning of hydrogen and chlorine to
form hydrogen chloride, operating on the chlorine-rich side
provides more troublesome waste than operating on the hydrogen-
rich side. Similarly, aluminum chloride made on the chlorine-
rich side requires air scrubbing to remove excess chlorine, while
the aluminum-rich side does not.
Many chemical reactions are either faster and more complete at
high temperatures or are exothermic and generate high tem-
peratures. To produce, control and/or reduce these temperatures,
cooling water and steam are often used. If the water or steam is
used without contact (such as in a shell and tube heat
exchanger), it is hot contaminated. If, however, the water or
steam contacts the reactants, then contamination of the water
results and the waste load increases. Therefore, reaction
heating and cooling should be non-contact whenever feasible.
Separations, purifications and recoveries
After reaction, the products, by-products, impurities, inerts and
other materials present need to be separated, purified and
recovered. Separations are carried out exploiting differences in
boiling points, freezing points, solubility and reactivity to
separate products from impurities, by-products and wastes. The
efficiency of these determines:
1. the fraction of product that is lost as waste or has to be
recycled;
2. the purity of the product;
3. control of air pollutants;
4. the recovery and/or disposition cf by-products and wastes.
The more complete the separations into recovered product, raw
materials that can be recycled, and wastes, the smaller the waste
load from the process. The degree of separation actually
achieved in the process depends on physical, chemical and
economic considerations. These effects will be discussed for the
individual chemicals of this study as they apply.
Cooling water and steam are also used in large quantities in the
separation and purification steps. The same concepts apply as
discussed in the reaction section. Indirect heating and cooling
may, in many instances, virtually eliminate waterborne wastes.
Segregation
Probably the most important waste control technique, particularly
fcr subsequent treatment feasibility and economics, is
segregation.
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Incoming pure water picks up contaminants from various uses and
sources including:
1. non-contact cooling water
2. contact cooling water
3. process water
4. washings, leaks and spills
5. incoming water treatments
6. cooling tower blowdowns
7. boiler blowdowns
If wastes from these sources are segregated logically, their
treatment and disposal may sometimes be eliminated entirely
through use in other processes or recycle, in many instances,
the treatment costs, complexity and energy requirements may be
significantly reduced. Unfortunately, it is a common practice
today to blend small, heavily contaminated streams into large
non-contaminated streams such as cooling water effluents. Once
this has been allowed to happen, treatment costs, energy
requirements for these treatments, and the efficient use of water
resources have all been comprised. In general, plant effluents
can be segregated into:
1. Non-contaminated cooling water. Except for leaks, noncontact
water has no waste pickup. It is usually high volume.
2. Process Water. Usually contaminated but often small volume.
3. Auxiliary Streams. Ion exchange regenerants, cooling tower
tlowdowns, toiler blowdowns, leaks, washings - low volume but
often highly contaminated.
Although situations vary, the basic segregation principle is
don't mix large uncontaminated cooling water streams with smaller
contaiminated process and auxiliary streams prior to full
treatment and/or disposal. It is almost always easier and more
economical to treat and dispose of the small volumes of waste
effluents - capital costs, energy requirements, and operating
costs are all lower. The use of segregation will be discussed
for individual chemical processes.
Monitoring techniques
Since the chemical process industry is among the leaders in
instrumentation practices and application of analytical tech-
niques to process monitoring and control, there is rarely any
problem in finding technology applicable to waste water analysis.
Acidity and alkalinity are detected by pH meters, often installed
for continuous monitoring and control.
Dissolved solids concentrations may be estimated by conductivity
measurements, suspended solids by turbidity, and specific ions by
211
-------
wet chemistry and calorimetric measurements. Flow meters of
numerous varieties are available for measuring flow rates.
The pH meter is the most universal of the in-line monitoring
instruments. In acid plants, hydrochloric, sulfuric, phosphoric,
nitric, hydrofluoric, and chromic acid leaks in coolers,
distillation columns, pumps and other equipment can tie picked up
almost at once. Spills, washdowns and other contributions also
become quickly evident. Alarms set off by sudden pH changes
alert the operators and often lead to immediate plant shutdowns
or switching effluent to emergency ponds for neutralization and
disposal. Use of in-line pH meters will be given additional
coverage in the control and treatment sections for specific
chemicals.
j
For monitoring and control of harmful, materials such as
chromates, batch techniques may be used. Each batch is analyzed
before dumping. This approach provides absolute control of all
wastes passing through the system. Unless the process is
unusually critical, dissolved solids are not monitored
continuously. Chemical analyses on grab or composite effluent
samples are commonly used to establish total .dissolved solids,
chlorides, sulfates and other low ion concentrations.
Safety, housekeeping containment
Many of the chemicals of this study or their wastes are either
harmful and/or corrosive. Examples are the acids, chromates,
chlorine, sodium hydroxide, sodium, and potassium. Mercury from
chlor-alkali plants is an example of a harmful waste. Con-
tainment and disposal requirements may be divided into several
categories:
1. minor product spills and leaks
2. major product spills and leaks
3, upsets and disposal failures
U. rain water runoff
5. pond failures
Minor spills and leaks
There are minor spills and leaks in all industrial inorganic
chemical manufacturing operations. Pump seals leak, hoses drip,
washdowns of equipment are necessary, pipes and equipment leak,
valves drip, tank leaks occur, solids spill and so on. The
quantity of waste water as a result of leaks and spills is
usually reflected by the company or plant's managerial philosophy
relative to housekeeping, washdown and production planning.
Leaks and spills represent a potential hazard to workmen in the
area of the spill or leak. In some cases the products are
valuable (such as hydrofluoric acid and titanium dioxide where
every pound lost is like throwing a quarter down the drain). In
212
-------
other cases, where -the financial loss may not fee as great,
personnel safety and equipment corrosion may become paramount.
When a leak develops in the heat exchanger of a sulfuric acid
plant, the plant shuts down before corrosion gets out of hand.
Also, phosphorus is not handled carelessly.
Reduction techniques are mainly good housekeeping and attention
to sound engineering and maintenance practices. Pump seals or
type of pumps are changed. Valves are selected for minimizing
drips. Pipe and equipment leaks are minimized by selection of
corrosion-resistant materials.
Containment techniques include drip pans under pumps, valves,
critical small tanks or equipment, and known leak and drip areas
such as loading or unloading stations. Solids can be cleaned up
or washed down. All of these minor leaks and spills should then
go to a containment system, catch basin, sump pump or other area
that collects and isolates all of them from other water systems.
They should go from this system to suitable treatment facilities.
The above mentioned techniques are being used effectively in a
number of plants today, and in many cases with enhanced
profitability.
Upsets and disposal failures
In many processes there are short term upsets. These may occur
during startup, shutdown or during normal operation. Although
these upsets represent a very small portion of overall pro-
duction, they nevertheless contribute to waste loads and must be
treated. The upset products may be segregated and possibly
reused. In the event that this can not be done, they must be
disposed of. Disposal failures require emergency tanks and/or
ponds- or some other expediency for temporary holding or
disposition.
Pcnd failures
Unlined ponds are the most common treatment facility used by the
inorganic chemical industry. Failures of such ponds occur
because they are unlihed and because they are improperly
constructed for containment in times of heavy rainfall.
Unlined ponds may give good effluent control if dug in impervious
clay areas or poor control if in porous, sandy soil. The porous
ponds will allow effluent to diffuse into the surrounding earth
and water streams. This may or may not be detrimental to the
area, but it is certainly poor waste control. Lined ponds are
the only answer in these circumstances. Many ponds used today
are large low-diked basins. In times of heavy rainfall, much of
the pond content is released into either the surrounding
countryside or, more likely, into the nearest body of water.
213
-------
TOBLE 40. Raw Water and Anticipated Analyses
After Treatmsnt
mg/1 as Ca CO3
ro
Substance
Cations
Anions
Bicarbonate)
Carbonate ) AUcaliniiy
Hydroxide )
Phosphate )
Anions
Chloride
Sulfate
Nitrate
Iron & Manganese
Total Solids (Cations + SiO2) .
-Ca++
.MtfH-
.Na++
.Hf
HCO3-
CO3—
OH-
PC4
Cl-
SO4—
N03-
as 002
. .as tti & Fe
1
100
100
100
0
300
150
0
0
0
75
75
0
300
200
150
0
50
0
mg/1
30
15
10
50
10
315
2
35
58
100
0
198
0
35
0
0
79
79
0
193
93
35
17
58
0
iog/1
0
A
0.2b
0.2b
10
208
3
58
7
85
0
150
0
21
0
0
64
63
0
150
65
23
14
55
0
fflg/l
0
5
0.2b
0.2b
10
155
4
1
1
298
C
300
150
0
0
0
75
75
0
300
2
150
0
0
150
OTT/I
30
15
0.2
0.2c
10
31 •»
5
1
164
0
165
15
0
0
0
75
75
0
165
1
15
0
0
164
mg/1
5-10
15
0.2
3 0.2c
10
180
6
—
5
-
-
5
rm
__
_
_
lfcr/1
5-10
15
0.2
0.2c
10
20
7
—
5
-
-
5
_
_
_
,_
_
nw/1
0
0.02
0.2
: 0.2c
10
5
8
100
100
100
0
300
150
0
0
0
75
75
0
300
200
150
0
50
0
mcr/1
30d
15
0.2c
0.2c
10
315
9
100
100
100
0
300
150
0
0
0
75
75
0
300
200
150
0
50
0
ma/I
30d
15
0.3
0.2c
10
315
(continued on next page)
-------
other cases, where the financial loss may not fce as great,
personnel safety and equipment corrosion may become paramount.
When a leak develops in the heat exchanger of a sulfuric acid
plant, the plant shuts down before corrosion gets out of hand.
Also, phosphorus is not handled carelessly.
Reduction techniques are mainly good housekeeping and attention
to sound engineering and maintenance practices. Pump seals or
type of pumps are changed. Valves are selected for minimizing
drips. Pipe and equipment leaks are minimized by selection of
corrosion-resistant materials.
Containment techniques include drip pans under pumps, valves,
critical sirall tanks or equipment, and known leak and drip areas
such as loading or unloading stations. Solids can be cleaned up
or washed down. All of these minor leaks and spills should then
go to a containment system, catch basin, sump pump or other area
that collects and isolates all of them from other water systems.
They should go from this system to suitable treatment facilities.
The above mentioned techniques are being used effectively in a
number of plants today, and in many cases with enhanced
profitability.
Upsets and disposal failures
In many processes there are short term upsets. These may occur
during startup, shutdown or during normal operation. Although
these upsets represent a very small portion of overall pro-
duction, they nevertheless contribute to waste loads and must be
treated. The upset products may be segregated and possibly
reused. In the event that this can not be done, they must be
disposed of. Disposal failures require emergency tanks and/or
ponds- or some other expediency for temporary holding or
disposition.
Pond failures
Unlined ponds are the most common treatment facility used fcy the
inorganic chemical industry. Failures of such ponds occur
because they are unlined and because they are improperly
constructed for containment in times of heavy rainfall.
Unlined ponds may give good effluent control if dug in impervious
clay areas or poor control if in porous, sandy soil. The porous
ponds will allow effluent to diffuse into the surrounding earth
and water streams. This may or may not be detrimental to the
area, but it is certainly poor waste control. Lined ponds are
the only answer in these circumstances. Many ponds used today
are large low-diked basins. In times of heavy rainfall, much of
the pond content is released into either the surrounding
countryside or, more likely, into the nearest body of water.
213
-------
Again, whether, this discharge is harmful or not depends on the
effluent and the surrounding area, but it does represent poor
effluent control and may not be permitted by local. State or
Federal authorities.
Good effluent control may be gained by a number of methods,
including:
1. Pond and diking should be designed to take any anticipated
rainfall - smaller and deeper ponds should be used where
feasible,
2. Control ponds should be constructed so that drainage from the
surrounding area does not inundate the pond and overwhelm it.
3. Substitution of smaller volume (and surfaced) treatment tanks,
coagulators or clarifiers can reduce rainfall influx and leakage
prcblems.
Treatment and Disposal Methods
After the in-process control practices discussed in the previous
section have teen utilized, treatment is usually required for the
contaminated streams. In general, these streams may be divided
into one of three categories: cooling water, process water, and
ancillary water.
Cooling water, either once-through or recycled by means of a
cooling tower, should be relatively free of wastes. Any
contaminants present would come from leaks (stream to be sent to
emergency pond as soon as control monitoring picks it up) or
recycle buildups (cooling tower) which are handled as ancillary
water blowdowns. In either event, cooling waste contributions
are small and treatment, except for incoming water purification,
should net normally be needed.
Process and ancillary waterborne wastes do require treatment.
The type, degree and costs involved will depend upon specific
circumstances unique for each chemical. Various treatment
techniques commonly used in the inorganic chemicals manufacturing
industry include settling ponds or vessels, filtrations, chemical
treatments, centrifugation, evaporation, drying, and carbon
adsorption.
Incoming surface water from streams, lakes, or oceans is often
filtered to remove suspended objects and solid particles,
chemically treated for clarification (small suspended solids
particle removal), controlled for pH and chlorinated for BOD
control. Ion exchange is used to replace undesirable calcium,
magnesium, carbonate and other ions which plate out on boiler,
water tower and process equipment as they are concentrated,
aerated or subjected to pH changes.
214
-------
Waste water streams are often subjected to filtrations to remove
minor suspended solids. screens, cloths, cartridges, bags,
candles and other mechanisms are used. The driving force may be
gravity, pressure or vacuum. Usually the filters are precoated
with diatomaceous earth or other filter aids.
Minor chemical treatments on waste water streams include
neutralizations for pH control, equalization of streams in a pond
or tank to minimize waste composition fluctuations, and chemical
reactions or precipitations to remove undesired components.
Settling ponds or vessels are the major mechanism used for
reducing the suspended solids content of water waste streams
coming from the plant. Their performance and cost depends en the
amount of waste involved and the settling characteristics of the
solids suspended. In the lower cost category they are small,
reflecting either fast settling and/or small, flow rates.
Costs for the above treatments may, in some cases, be derived in
the following sections as extrapolations.
Higher cost treatments are rarely needed for incoming water
(except in cases where either only very poor quality water is
available or very low TDS is required). They are more applicable
for treating waste effluents.
Ion Exchange and Demineralizations
Icn exchange and demineralizations are usually restricted in both
practice and costs to total dissolved solids levels of 1000 to
4000 mg/1 or less. Table UO gives water compositions as a
function cf water treatments, including ion exchange and
demineralization.
An ion exchanger may be simply defined as an insoluble solid
electrolyte which undergoes exchange reactions with the ions in
solution. An exchanger is composed of three components: an
inert matrix, a polar group carrying a charge and an exchangeable
ion carrying an opposite charge. The inert matrix today is
usually a cross-linked polymeric resin containing the needed
polar groups.
There are two types of ion exchangers; cation and anion. Cation
exchangers contain a group such as sulfonic or carboxylic acid.
These can react with salts to give products such as the
fcllowing:
RS03H + NaCl = RSO3Na + HC1
RCO2H + NaCl = RCO2Na + HCl
215
-------
TAKT.K 40. Raw Water and Anticipated Analyses
After Treatment
mg/1 as Ca 003
ro
Substance
Cations
Hydrogen Acidity
Total Cations
Anions
Bicarbonate)
Carbonate ) Alkalinity
Hydroxide )
Phosphate )
Anions
Chloride
Sulfate
Nitrate
Total Anions
Iron & Manganese
Total Solids fCations + SiO2) .
,Ca++
.Na++
HC03-
003—
OH-
PO4
Cl-
SO4—
N03-
as 002
..as 1*1 & Fe
1
100
100
100
0
300
150
0
0
0
75
75
0
300
200
150
0
50
0
30
15
10
50
10
115
2
35
58
100
0
198
0
35
0
0
79
79
0
193
93
35
17
58
0
0
A
0.2b
0.2b
10
208
3
58
7
85
0
150
0
21
0
0
64
63
0
150
65
23
14
55
0
0
5
0.2b
10
155
4
1
1
298
C
300
150
0
0
0
75
75
0
300
2
150
0
0
150
mr/1
30
15
0.2
0.2c
10
5
1
164
0
165
15
0
0
0
75
75
0
165
1
15
0
0
164
mg/1
5-10
15
0.2
: 0.2c
10
180
6
_
_
—
5
-
-
5
_
_
_
_
.
M&A
5-10
15
0.2
0.2c
10
20
7
_
—
5
-
-
5
_
_
_
_
_
ma/1
3
0.02
0.2
2 0.2c
10
5
8
100
100
100
0
300
150
0
0
0
75
75
0
300
200
150
0
50
0
ma/1
303
15
0.2c
0.2c
10
315
9
ion
inn
inn
0
300
150
0
0
0
75
75
0
300
200
TiO
0
•sn
n
ma
10
0.
0*
10
r/i
r\
3
'(*<"•
(continued on next page)
-------
TABLE 40. Raw Water and Anticipated Analyses
After Treatment (cent.)
1. Raw water
2. After cold line softening and filtration
3. After hot process softening and filtration
4. Ion exchange softening
5. Sodium and hydrogen unit blend and degasification
6. Two-step demineralizaticn (weak anion exchange) and degasification
7. Two-step demineralization {strong base anion resin) and degasification
8. Aeration and filtration
9. Manganese zeolite filters
a. Some reduction will occur
b. Filtered effluent
c. With proper pretreatment
d. Affected by pH adjustment
e. Iron only
Note: Ion exchange processes assume that the water was adequately pretreated.
217
-------
The above reactions are reversible and can be regenerated with
acid.
Anion exchangers use a basic group such as the amino family.
RNA3OH + NaCl-»-RNA3Cl + NaOH
This is also a reversible reaction and can be regenerated with
alkalies. The combination of water treatment with both cation
and anion exchangers removes the dissolved solids and is known as
demineralization (or deionization). The quality of demineralized
water is excellent. Table 41 gives the level of total dissolved
solids that is achievable. Membrane and evaporation process
water contain significantly higher solids content and need final
polishing in a demineralizer if less than 3 mg/1 dissolved solids
level is required for the application. There are many
combinations of ion exchangers which can be used for
demineralizations.
Four types of demineralization units will be discussed in the
cost analysis development to follow:
1. Fixed bed - strong cation - strong anion
2. Fixed bed - strong cation - weak anion
3. Mixed bed demineralizers
4. Special ion exchange systems.
Special ion exchange systems have been developed for concentra-
ting high dissolved solids content (more than 1000 mg/1 total
dissolved solids), minimizing regenerant chemicals costs, some
of these special systems are listed in Table 42.
Ion exchange is rarely used to concentrate dissolved solids in
waste streams unless some specific ion or ions need to be
removed. In fact, usually little overall is gained by this
technique since regenerations generate wastes that are often as
troublesome to dispose of as the original dissolved materials.
Also, the cost of treating waste water with a total dissolved
solids concentration of only 1000 mg/1 is not low.
Demineralization can often be used for concentrating wastes.
Chemical Treatment
Chemical treatments for abatement of water-borne wastes are
widespread. Included in this overall category are such important
subdivisions as neutralization, pH control, precipitations and
segregations, harmful and undesirable waste modification and
miscellaneous chemical reactions.
a. Neutralization
Most of the inorganic chemicals of this study are either acidic,
alkaline or react with water to give acidic or alkaline
218
-------
Residual
Silica
mg/1
No silica
removal
Residual
Electro-
lytes ,
mq/1
3
Specific
Resistance
ohm- cm
3 25*C
500,000
TABLE 41. Water Quality Produced by Various
ion Exchange Systems
Exchanqer S etup
Strong-acid
cation + weak-
base an ion
Strong-acid 0.01-0.1 3 100,000
cation + weak-
base anion +
strong-base
anion
Strong-acid 0.01-0.1 0.15-1.5
cation + weak-
base anion +•
strong-acid
cation + strong-
base anion
Mixed bed 0.01-0.1 0.5
(strong-acid
cation + strong- -*
base anion)
Mixed bed 0.05 0.1
+ first or second
setup above
Similar setup at 0.01 0.05
immediately above
+ continuous re-
circulation
1,000,000
1-2,000,000
3-12,000,000
18,000,000
219
-------
TABLE 42. Special Ion Exchange Systems
System I
Application: Feedwater with high solids contents (above 1000 mg/1
TDS). There are two variations of this system — two-bed or threebed
setup. Two-bed system consists of weak-base (HCO3) anion + weak-acid
(H) cation exchangers followed by a decarbonator unit. NH4OH and CO2_
are used to regenerate the anion exchanger and sulfuric acid to
regenerate the cation exchanger, in place of decarbonate a second weak-
base (OH) anion exchanger is used in the three-bed Desal system.
System advantages: high flow rates; carbon dioxide recovery, good
regenerant efficiency. Limitations: solids content of water must be
less than 2000 mg/1; highly alkaline feedwater needed for best
performance; iron in feedwater cannot be tolerated.
System II
Application: Feedwater with high solids content.
Also employs two- or three-bed setup. Two-bed system consists of
strong-acid (H) cation + strong-base (3(54) anion exchangers followed by
decarbonator. Sulfuric acid used to regenerate cation exchanger, raw
water the anion exchanger. In three-bed system a weak-acid (H) cation
exchanger precedes the strong-acid cation exchanger.
Advantages: raw water can be used to regenerate the strongbase anion
exchanger; high quality rinse-water not required. Limitations: ratio
of SOU to Cl in feedwater must be high; requires high volume of rinse
water; low capacity.
System III
Application: Feedwater with high solids content,
Four-bed systems consisting of: strong-base anion (HCO3) •*- weak-acid
cation (H) + strong-acid cation (H) + weakbase anion (OH) exchangers.
NaHCO3 is used to regenerate anion exchangers; sulfuric acid to
regenerate cation exchangers.
220
-------
TABLE 42. special ion Exchange Systems (continued)
System III (continued)
(continued)
Advantages: may be used on feedwater containing up to 3000 mg/1 solids,
content; high capacity and regenerant efficiency. Limitations: number
of columns required; low service flow rates; high cost of regenerants.
System IV
Application: Condensate desalination
Mixed-bed ion exchangers have been plagued by the fact that complete
resin separation is difficult to achieve — some cation resin remains
mixed with anion resin after backwashing, with the result that sodium is
released sooner (lower capacity) ; some leakage occurs (affecting water
quality) since ammonia is usually present in condensate. This is
overcome in Ammonex process by regenerating cation exchanger with acid
and first regenerating anion exchanger with caustic and then with
ammonia to remove the sodium present in anion exchanger.
Sy.stem_V
kPJ2lication : Condensate desalination
Water quality and run length improved similarly as in Ammonex process
except that anion exchanger is regenerated with caustic and lime rather
than caustic and ammonia.
System VT
Application; Condensate desalination
Water quality and run length improved by separating mixedbed with strong
caustic solution then regenerating beds in customary procedure; i.e.,
with acid for cation exchanger and caustic for anion exchanger.
221
-------
Centrifuges are not widely used for inorganic chemical waste
streams, since it is rare that settling ponds or filters are not
adequate for the same suspended solids removal job.
Carbon adsorption
On the rare occasions that inorganic chemicals waste streams
contain organic materials, one of the appropriate treatments to
remove these organic components is carbon adsorption. When waste
streams containing organic contaminants are passed through
activated carton beds, the organic material is adsorbed. When
the carbon bed is saturated with this organic substance, the bed
may be regenerated by burning off the adsorbed organic and
returning the carbon to service.
Reverse Osmosis
The small pore size of the reverse osmosis membrane is both its
strength and its weakness. Its strength comes from the molecular
separations that it can achieve. However, it is susceptible to
blinding, plugging, and chemical attack. Acidity, suspended
solids, precipitations, coatings, dirt, organics and other
substances can make it inoperative. Membrane life is critical
and difficult to predict in many cases. Because of these
restrictions its industrial applications are few. Fortunately,
the inorganic chemistry industry water purification needs are
similar to those of the areas where reverse osmosis has been
shown to be applicable — treatment of brackish water and low
(500-20,000 mg/1) dissolved solids removal. Organics are usually
absent, suspended solids are low or can be made low rather
easily, acidity is easily adjusted, and most of the dissolved
solids are similar to those in brackish water — sodium
chlorides, sulfates and their calcium counterparts.
The reverse osmosis membranes used commercially are generally one
of two types ~ flat sheet or hollow fiber. For maximum membrane
area in the smallest space, various sheet configurations have
been devised including tubes, spiral winding, and sandwich-type
structures. Sheet membranes have been largely cellulose acetate,
while hollow fibers have been largely polyamides.- costs for
different membrane configurations are roughly comparable. The
type selected depends upon the specific application.
Regardless of membrane type or material, the basic unit of
construction is the module (or package of membrane materials) .
The module is usually integral and of the plug-in type, where a
faulty module can be easily (but not inexpensively) replaced.
The modules are the heart of the reverse osmosis process, with
ancillary equipment such as pumps, tanks, piping, pretreatment
facilities and other hardware performing peripheral functions.
Module cost alone comprises one-third to one^half of the in-
stalled capital investment.
224
-------
Detailed cost figures, both capital and operating, are given in
Section VIII.
Evaporation Processes
Evaporation is the only method of general usefulness for the
separation and recovery of dissolved solids in water. Other
processes either involve mere concentration (reverse osmosis) or
introduce contaminations for subsequent operations (demineralizer
regenerants and chemical precipitations).
The evaporation process is well known and well established in the
inorganic chemical industry, separations, product purifications,
solution concentrations are commonly accomplished by evaporative
techniques. In-depth technology for handling the common
dissolved solids in water waste streams has been developed in the
soda ash, salt, calcium chloride, and sea water chemical
industries. In addition, numerous desalination plants producing
fresh water from brackish or sea water are scattered all over the
world and have been in operation for a number of years. Seawater
generally has approximately 35,000 mg/1 dissolved solids (3.5
percent by. weight) while brackish water has 2,000 to 25,000 mg/1
depending on location.
Evaporation is a relatively expensive operation. To evaporate
one kg of water, approximately 550 kg-calories of energy is
required and the capital cost for the evaporating equipment is
not low. For these reasons industrial use of evaporation in
treating waste water has been minimal. As the cost of pure water
has increased in portions of the United States and the world,
however, it has become increasingly attractive to follow this
approach.
The treatment of water waste streams by evaporation almost always
has utilized the principle of multi-effects to reduce the amount
of steajr cr energy required. Thus, the theoretical difficulty of
carrying out the separation of a solute from its solvent is the
minimum amount of work necessary to effect the particular change,
that is the free energy change involved. A process can be made
tc operate with a real energy consumption not greatly exceeding
this value. The greater the concentration of soluble salts, the
greater is the free energy change for separation, but even for
concentrated solutions the value is much lower than the 550 kg-
cal/kg value to evaporate water. Multi-effect evaporators use
the heat content of the evaporated vapor stream from each
preceding stage to efficiently (at low temperature difference)
evaporate more vapor at the succeeding stages. Thus the work
available is used in a nearly reversible manner, and low energy
requirement results. However, a large capital investment in heat
transfer surface and pumps is required. The interaction of the
capital equipment costs versus energy or operating costs will be
discussed in detail in the treatment costs section.
225
-------
prying
After evaporative techniques have concentrated the dissolved
solids to high levels, the residual water content must usually be
removed before recovery, sale or disposal. Water content will
range from virtually zero up to 90 percent by weight. Gas- or
oil-fired dryers, steam-heated drum dryers or other final
moisture-removing equipment can be used for this purpose. Since
this drying operation is a common one in the production of
inorganic chemicals themselves, technology is well known and
developed. Costs are mainly those for fuel or steam.
Disposal Practices
Disposal of the waterborne wastes from inorganic chemicals
manufacturing represents the final control exercised by the waste
producer. A number of options are available. They include
discharge to surface water —- river, lake, bay or ocean — and
where safe and permitted, land disposal by running the effluent
out on land and letting it soak in or evaporate. Wastes may be
disposed of into an industrial waste treatment plant. Treatment
and reuse of the waste stream can also be practiced. In dry
climates unlined evaporation ponds, if allowed, could be used.
Higher-cost disposal systems include lined evaporation ponds,
deep well disposal, and high-cost treatment prior to disposal or
recovery. Such methods are used for wastes which cannot be
disposed of otherwise. These wastes contain strong acids or
alkalies, harmful substances, or large quantities of dissolved
solids.
Feasibility, use, and cost figures can be discussed for:
1. unlined evaporation ponds
2. lined evaporation ponds
3. deep wells
Unlined Evaporation Ponds
Two requirements must be met for an unlined evaporation pond to
be successfully utilized. First, it must be located in an area
in which unlined ponds are allowed, and secondly, the rainfall in
that area must not exceed the evaporation rate. This second
requirement eliminates most of the heavily industrialized area.
For the low rainfall areas, evaporation ponds are feasible with
definite restrictions. Ponds must be large in area for surface
exposure. Evaporation of large amounts of waste water requires
large ponds. The availability and costs of sufficient land place
another possible restriction on this approach.
226
-------
Lined Evaporation Ponds
The lined evaporation ponds now required in some sections of the
country have the same characteristics as developed for the un-
lined ponds — large acreage requirements and a favorable evap-
oration-rainfall balance. They are significantly higher in cost
than an unlined pond. Such costs are developed in Section VIII.
Reduction of the evaporation load is a significant advantage.
For this reason, plus the short supply and high cost of water in
much of southwestern United States, distillation and memtrane
processes are beginning to be used in these regions.
Deep wells
Deep well disposal can only be used under special conditions
consistent with State and Federal regulations. While used for
brine disposal in the petroleum and salt industries, deep wells
are usually reserved for wastes such as strong acids, chromates,
pickle liquor, and corrosive metallic salt solutions for which no
other disposal system is available or environmentally acceptable.
Deep well disposal should be considered only a temporary
expedient until suitable recovery, reuse, or treatment methods
are developed and demonstrated to be practical.
There are several reasons for this specialization, including:
1- Costs - A single well costs up to $1,500,000 depending
depth, drilling ease and criticalness, casing, exploration
m/"»»i T -t-r\v T nit •! nlTi"(1 trorl
on
exploration and
monitoring involved.
2. Geological - The geological structure in the area is of
utmost importance. In many parts of the country, deep wells are
not possible. Even in those sections where the geological
structure permits their use, deep wells must be carefully planned
and coordinated using the best geological information and
expertise available,
3- Drilling Consideratjons - Deep wells are drilled by
specialists using oil well technology. While this technology is
well developed, there is always the possibility that something
expensive will go wrong — cracks, lost drills, impermeable
formations, etc.
4^ Reliability - Deep wells often plug or develop operating
difficulties even after several years of good performance.
5- Extensive Pretreatment may be necessary to remove or-
ganics, suspended solids and other undesirable waste components.
6. The risk of contamination of underground potable water or
seismic effects.
Ko£t wells are approximately the same size and range in flow rate
from 12.6-56.8 I/sec with the average being about 18.9-^.^
1/oec. This corresponds to approximately 1890 cu m/day capacity.
227
-------
-------
SECTION VIII
COST, ENERGY AND NON-WATER QUALITY ASPECTS
CCST AND REDUCTION BENEFITS OF TREATMENT
AND CONTROL TECHNOLOGIES
The inorganic chemical industry has large energy requirements for
gas furnaces, kilns, calciners, electric furnaces, reactors,
distillation columns, and evaporators and other common equipment.
In contrast, treatment practices consume less than one tenth of
one percent of this amount. Chemical reactions and pond
settling, the most commonly used treatments, required almost nc
energy. Filtrations, centrifuging, and other separation
techniques are still relatively low energy processes. The only
two high energy treatments, evaporation and drying, are now
rarely used. Utilizing these treatment techniques to the extent
covered in the cost effectiveness discussions later in this
section will still maintain treatment energy at a tiny fraction
of the total energy for the industry. Table 43 summarizes cost
and energy requirements for the manufacture of the inorganic
chemicals of this report. To bring the processes to zero water-
borne waste effluent through total recycle of process water,
rough estimates for additional capital expenditures are 295
million dollars. Of this amount, three Industrie s contribute
almost eighty percent. These industries — soda ash (Solvay
Process), chlor-alkali, and titanium dioxide — have vastly
different situations from the other chemicals.
Titanium dioxide has no satisfactory replacement. It can absorb
and pass on the large capital and operating costs needed for
waterborne waste cleanup. This major clean-up is also long
overdue. Development and application of existing treatment
technology can save the titanium dioxide industry an estimated
100 million dollars over the full neutralization costs given in
Table 43.
The chlor-alkali industry differs from both soda ash (Solvay) and
titanium dioxide in that mainly in-process changes and more
efficient use of raw materials are required to attain zero water-
bcrne waste. There are many ways to accomplish this, some of
which are suggested in Sections VII and VIII of this report.
Other industries that have major capital expenditures in Table
43, sulfuric acid, nitric acid, sodium metal (which is similar in
process wastes to chlor-alkali plants), aluminum sulfate, sodium
dichromate, and sodium chloride (brine or mining) have these
costs primarily because of the large size of the industry or
harmful wastes. Except for sodium chloride (brine or mining) and
sodium dichromate, all waste abatement costs for these chemicals
are below 1.5 percent of the list price.
229
-------
TABLE 43. Summary of Cost and Energy Information for Attainment of Zero Discharge
Additional Energy
ro
OJ
o
Chemical
Aluminum Chloride
Aluminum Sulfate
Calcium Carbide
Hydrochloric Acid
Hydrofluoric Acid
Lime
Nitric Acid
Patasslum Metal
Potassium Chromates
Sodium Bicarbonate
Potassium Sulfate
Sodium Chloride (Solar)
Sodium Silicate
Sulfuric Acid
Hydrogen Peroxide
(Organic)
Sodium Metal
Sodium Sulfite
Calcium Chloride
Sodium Chloride (brine)
Chlor-Alkali
Hydorgen Peroxide
(Electrolytic)
Additional
Capital, $
0
4,700,000
0
250,000
1,180,000
0
11,000,000
io6 io6
Btu/yr Kg cal/yr
0
17,000
0
0
3300
0
0
0
4300
0
0
8350
0
0
Incremental
Cost
$/ton
0
0.90
0
0.05
13-16
0
0.22
$/metric ton
0
1.0
0
0.06
14-18
0
0.24
Percent of June, 1973"
List List Price
Price
0
1*4
0
0.04
2.5
0
0.18
$/ton S/metric ton
>255
62.80
171,40
110 (100%) 121
560 (100%) 617
19.50-
21.75
113 (100%) 124
280
69
188
21.50-
24
0
90,000
0
1,570,000
0
850,000
20,000,000
350,000
4,700,000
3,730,000
1,040,000
7,750,000
40,000,000
15,000
0
210
0
680,000
0
332,000
0
0
0
116,000
0
0
800,000
870
0
53
0
162,000
0
84,000
0
0
0
29,300
0
0
202,000
220
0
4.65
0
1.60
2.20
0.90
0.10
1.00
2.25
2.50
0.20
1.00
0.50
(combined
0.25-.75
0
5.15
0
1.16
2.42
1.0
0.11
1.10
2.48
2.75
0.22
1.10
0.45
product
0.27-.83
0
0.97 480
0 88
3,7 42.50
25.9-11.0 8,30-20
0.95 95
.33 28-32
0.2 460
(70%Sol'n)
0.6 375
2.1 117
0.5 42
7.15-4.16 14-24
~0.5 Cla$75
basis) NaOH $110
(75%)
0.1 460
528
97
47.50
9.40-22
102
30.75-35
505
412
129
46
15.40-26.45
$83
$121
507
(70%Sol'n)
(continued on next page)
-------
TABLE 43. Summary of Cost and Energy Information For Attainment of Zero Discharge (continued)
Chemical
Sodium Dichromate
Sodium Sulfate
Soda Ash
Titanium Dioxide
(Chloride)
Titanium Dioxide
(Sulfate)
Totals
Additional
Capital, $
4,100,000
0
*****25,000,000
****74,000,000
96,000,000
294,895,000
Additional
106
Btu/yr
240,000
0
2001,000
675,000
535,000
3,590,000
Energy,
10"
kg cal/yr
60,700
0
50,200
170,000
135,000
905,000
Incremental Percent of June, 1973
$/ton
16
0
1.60
64
96
—
Cost
$/metrtc ton
18
0
1.76
70
103
—
List
Price
4.6
0
4.5
11.4
17.1
—
List Price
$/ton
345
24-33
35.50
550-570
550-570
—
$/metric ton
380
26-36
39
605-615
605-615
—
*
**
* **
Chemical Marketing Reporter, June 4, 1973.
Based on 3 million tons/year vacuum pan salt production from Salt, Bureau of Mines Minerals Yearbook, 1969.
Based on $2.00/ton chlor-alkali production — estimated from cost effectiveness data in SectlQfi VIII
****Based on full neutralization plus demineralization costs as given in Section VIII
*****Based on deep-welling costs as in section VIII
-------
For all chemicals except soda ash, titanium dioxide, sodium
dichromate, and sodium chloride (solar), the yearly cost for
total water-borne waste abatement is less than U percent of the
current list price.
Energy requirements of 9.05 x 10** kg cal/yr (3.6 X 10*2 BTU/yr)
or the energy equivalent to burning 10,220 cu m (3.6 million gal)
of fuel oil for the elimination of water-borne wastes for the
chemicals of this study are less than that currently consumed by
one large Solvay soda ash plant.
Thermal pollution was not encountered in this study nor was noise
or other types of pollutions.
In general, plant size itself does not appear to be a significant
factor influencing waste effluents on a kkg waste/kkg of product
basis. Multichemical complexes have an advantage over single
isolated facilities on costs and options for waste utilization.
Plant age does have some influence, with the new plants,
naturally, being favored. These are by no means the controlling
criteria, however. For example, nineteen exemplary plants used
in the cost effectiveness development given later in this section
have an average age of 21 years, with five plants of 30 years or
greater age and six of 10 years or less age.
Geographical location is often a critical factor for waste dis-
posal costs. Availability of deep welling, ocean barging, or
sclar evaporation options is an advantage. Also, the western
United States has more incentive to recover and reuse ocean water
than the east.
New plants being built can avoid major future waste abatement
ccsts by inclusion of:
(1) Dikes, emergency holding ponds, catch basins, and other
containment facilities for leaks, spills and washdowns.
(2) Piping, trenches, sewer, sumps and other isolation facilities
to keep leaks, spills and process water separate from cooling and
sanitary water.
(3) Non-contact condensers for cooling water. Barometric con-
densers should te avoided.
(U) A full water treatment system, including demineralization,
reverse osmosis, evaporative and solids waste handling equipment
when needed.
(5) Efficient reuse, recycling and recovery of all possible raw
materials and by-products regardless of inherent value. Sodium
chloride and sodium sulfate are two by-products which frequently
cause trouble.
(6) Closed cycle water utilization whenever possible. Closed
cycle operation eliminates all water-borne wastes. Generally, if
water is pure enough for discharge, it is pure enough for reuse.
232
-------
Cost References and Rationales
Cost information contained in this report was obtained directly
from industry during exemplary plant visits, from engineering
firms and equipment suppliers, and from the literature. The in-
formation obtained from these latter three sources has been used
to develop general capital, operating and overall costs for each
treatment and control method. Costs have been put on a
consistent industrial calculation basis of ten year straight line
depreciation plus allowance for interest at six percent per year
(pollution abatement tax-free money) and inclusion of allowance
for insurance and taxes for an overall fixed cost amortization of
fifteen percent per year. This generalized cost data plus the
specific information obtained from plant visits was then used for
the cost effectiveness estimates in this section and whenever
else costs are mentioned in this report*
Cost developments, calculations, references and rationale for
treatment and disposal techniques pertinent to the inorganic
chemicals industry are detailed in Supplement A. In addition to
the costs developed in Supplement A, costs for specific plant
treatment systems are given in Supplement B. The combination of
these two costs sources and engineering judgment extrapolations
from them are used for cost effectiveness development.
Definition of Levels of Control and Treatment
Using the general models as given in Figures 62 and 63, cost and
energy effectiveness values for each chemical subcategory have
been developed. Four levels of treatment and control are
considered:
Level A — Base level practices followed by most of the industry
and exceeded by exemplary plants,
Level B — Treatment and control practices at the average
exemplary plant.
Level C — Based upon the best technically and economically
feasible treatment and control technology.
Level D — complete water-borne waste elimination. This level
may or may not be economically feasible for the specific
chemical.
Aluminum Chloride
No water-borne process wastes are generated in the manufacture of
aluminum chloride. The only ancillary waste stream results from
wet air pollution control devices. Two exemplary plants have no
wastes from this source. Plant 125 has been chosen for cost
effectiveness development (see Table U4) . This is a 30 year old
233
-------
no
OJ
ANCILLARY
OPERATIONS
(COOLING
TOWER,
BOILERS)
V
WATER
TREATMENT
AREA
SOLID MAKEUP
WASTES WATER
-
HO
e>
.
>z<
v
OS:
A
uuu
PROCESS
A
EMERGENCY
POND
OR
TANK
TOXIC
CHEMICAL
REMOVAL
PROCESS
EFFLUENT
CHEMICAL
TREATMENT
SOLID
WASTES
f
SOLID
WASTES
EMERGENCY
TREATMENT
FACILITIES
SOLID
WASTES
V
SUSPENDED
SOLIDS
REMOVAL
PURE
WATER
DISCHARGE
FIGURE 62
MODEL FOR WATER TREATMENT AND CONTROL SYSTEM
INORGANIC CHEMICALS INDUSTRY
-------
FILTRATION
HIGH
DISSOLVED
SOLIDS
STREAMS
SUSPENDED
SOLIDS
REMOVAL
pH ADJUST
OTHER
CONDITIONING
ro
CO
tn
MAKEUP WATER
'HIGH
SOLIDS
STREAM
REVERSE
OSMOSIS
UNITS
LOW
DISSOLVED
SOLIDS
STREAMS
A
SUSPENDED
SOLIDS
REMOVAL
pH ADJUST
OTHER
CONDITIONING
V
INCINERATION,
FINAL
EVAPORATION
SOLID
WASTE
TO REUSE,
SALE OR
LANDFILL
LOW
ENERGY
EVAPORATION
REGENERANTS
FOR
POLISHING
V
SOFTENERS
ION EXCHANGERS
DEMINERIZERS
V
-> PURE WATER BOILERS,
WATER TOWERS AND
•> OTHER REQUIREMENTS
PROCESS WATER
OF
DESIRED PURITY
FIGURE
MODEL FOR WATER TREATMENT SYSTEM
INORGANIC CHEMICALS INDUSTRY
-------
TABLE 44
Water Effluent Treatment Costs
Inorganic Chemicals
Chemical: Aluminum Chloride (22.5 kkg/day (25 tons/day) Capacity)
Treatment of Control" Technolo-
gies Identif led under Item
III of the Scope of Work:
Investment
Annual Costs:
Interest + Taxes and
Insurance
Depreciation
Operating and Maintenance
Costs (excluding energy
and power costs)
Energy and Power Costs
Total Annual. Cost
Effluent Quality:
Effluent Constituents
Parameters (Units) Raw
) Waste
Load
A
25,000
1250
2500
20'00
3500
9250
BCD
100,000 100,000 100,000
5,000 5,000 5,000
10,000 10,000 10,000
15,000*** 15,000*** 15,000***
Resulting Effluent
Levels
Aluminum Chloride + ; 75(150)* 75(150)*
Chlorine (Airborne)
Level A - evaporation and reuse
Le»'e1 B - recycle of scrubber water
-2.5 (5)****
*Residual air-borne wastes (where scrubbers are used for air pollution abatement this is
water-borne).
**Operating costs of $18,000/yr balanced by sale of product as aqueous aluminum
chloride solution.
***Credited to air pollution control water pollution control cost is zero.
'***Air-borne waste passing scrubber, scrubber liquor sold or recycled.
236
-------
plant of nominal 22.5 kkg/day (25 ton/day) capacity. Treatment
facilities have been recently installed.
Energy requirements are low (small pumps and stirrers) and are
estimated to be 0.75 kwhr (1 hp-hr). converting this to common
units gives 5.3 x 10* kg cal (2.1 x 10* BTU).
For the entire industry, the energy requirement would be 1.7 x
10' kg cal (6.8 x 10' BTU).
Treatment costs for air pollution control are $1.88/kkg
($1.70/ton) of product. Treatment costs and energy requirements
fcr water pollution control are zero.
Aluminum Sulfate
Two exemplary closed-cycle plants, 049 and 063, were studied.
Plant 063 is chosen for cost effectiveness analysis. This 46
year old plant has an average production of 36 kkg/day (40
tons/day). Cost effectiveness information is given in Table 45.
Energy requirements for pumps, clarifiers, drives, etc., are
approximately 7.5 kwhr (10 hp-hr). Annual requirements are 5.3 x
107 kg cal (2.10 x 10* BTU).
Entire industry energy for treatment is estimated as 4.3 x 109 kg
cal (1.7 x 10io BTU).
Costs for closed cycle zero effluent operation are $1.87/ kkg
($1.70/tcn) of which $1.00/kkg ($0.90/ton) of product represents
additional cost above typical operation in all plants.
Calcium Carbide
The calcium carbide manufacturing process generates no water
borne waste. The only possible contributions result from wet air
pollution control devices used to remove dusts and particulates
frcm the gas streams. Costs for treating air pollution abatement
contributions to water effluents are credited to air pollution
costs. Therefore, energy and costs for waste water treatment for
calcium carbide are zero.
Fcr information purposes, a cost-effectiveness sheet. Table 46,
has been prepared showing air pollution abatement costs for plant
190. In this case air pollution control costs are zero since
recovered raw materials pay for total annual costs.
Calcium Oxide and Calcium Hydroxide
There is no water-borne waste from the process. Therefore, no
cost or energy is involved.
237
-------
For informational purposes cost effectiveness Table 47 is given
for eliminating air pollution. Cost is $1.45/kkg ($1.32/ton) for
dry bag collection installations. If water scrubbing plus
elimination of water-borne wastes is more economical than
$l,45/kkg ($1.32/ton) of product, then water scrubbing and reuse
may be used.
Calcium Chloride
Calcium chloride comes from two major sources, Solvay soda ash
by-product and brine chemicals by-product. A 45 year old, 450
kkg/day (500 ton/day) brine reclamation plant, 185, is used for
cost effectiveness development, as shown in Table 48.
Cost for elimination of present wastes is roughly estimated as
$0.22/kkg ($0.20/tcn) of product.
NO additional energy requirements are involved.
Chlorine and Potassium or Sodium Hydroxide
a) Mercury cell process
Both chlorine and sodium hydroxide are produced by the mercury
cell process. Potassium hydroxide is produced similarly by
starting with potassium chloride brine instead of sodium
chloride.
Cost effectiveness values are developed in Table 49 using two
year-old 158 kkg/day (175 ton/day) (chlorine basis) plant 098.
For zero water-borne wastes the cost above Levels A and E mercury
removal is approximately $1.00/kkg($0.90/ton) of chlorine
produced. Spreading these costs to chlorine and sodium hydroxide
co-products reduces the value to approximately $0.55/kkg
($0.50/ton) of products.
Roughly 2.52 x 10« kg cal/yr (1.0 x 10*o BTU/yr) additional
energy is required for this plant.
Plants have now reduced water effluent mercury discharges to
approximately 0.045-0.225 kg/day (0.1-0.5 Ib/day) by spending
Level A and B money. Some exemplary plants have spent Level C
money (plant 098 is at this level) .
b) Diaphragm cell process
Diaphragm cells also produce both chlorine and sodium hydroxide
(or potassium hydroxide if potassium chloride brine is used).
Table 50 gives the progressive cost effectiveness development for
one year old 2070 kkg/day (2300 ton/day) plant 057. Costs for
240
-------
TABLE 47
Water Effluent Treatment Costs
Inorganic Chemicals
Chemical: Lime - Air Pollution Costs Only (281 kkg/day (310 tons/day) Capacity)
Treatment of Control Technolo-
gies Identified under Item
III of the Scope of Work:
Investment
Annual Costs:
In-barest 4- Taxes and
Insurance
Depreciation
Operating and Maintenance
A
0
0
0
0
B
675,000
33,750
67,500
35,000
C
675,000
33,750
67,500
35,000
D
675,000
33,750
67,500
35,000
Oosts (excluding energy
and power costs)
Energy and Power Oosts
Total Annual Cost
Effluent Quality:
Effluent Constituents
Parameters (Units) Raw
kg/kkg (Pound|Aon) Waste
Load
2,500 2,500 2,500
138,750 138,750 138,750
Resulting Effluent
Levels
Kiln Dusts
67(134) 67(134)
Level B — Dry bag collectors installed.
241
-------
TABLE 48.
Water Effluent Treatment Costs
. Inorganic Chemicals
Chemical: Calcium Chloride (450 kkg/day (500 tons/day) Capacity)
Treatment of Control Technolo-
gies Identified under Item
III of the Scope of Work:
Investment
Annual Costs:
Interes'-. *• Taxes and
Insurant
Eepreciation
Operating and Maintenance
Costs (excluding energy
and power costs)
Energy and Power Costs
Total Annual Cost
A* .B C D
0 200,000 200,000 200,000
10,000 10,000 10,000
20,000 20,000 '20,000
0 00
30,000 , 30,000 30,000
Effluent Quality:
Effluent Constituents
Pararraters (Units)
kg/kkg (Pounds/Ton)
Calcium Chloride
Sodium Chloride
Ammonia
Baw
Waste
Load
30(60)
0.5(1)
0.5(1)
Resulting Effluent
Levels
30(60)
0.5(1)
0.5(1)
0.5(1)
0
0
-0
-0
~0
~o
~0
~0
Level A — Normally these wastes, as dissolved solids are discharged to surface water in
non-exemplary of soda ash plants.
Level B — Replacement of barometric condensers with non-contact heat exchangers.
Level C -- Elimination of packing station water-waste contributions.
''Level A corresponds to present performance of "exemplary" plant rn this table. Level B
modelled to near future plans of this plant.
242
-------
TABLE 49
/
Water Effluent Treatment Costs
Inorganic Chsnicals
Chemical: Mercury Cell Chlor-Alkali (158 kkg/day (175 tons/day) Capacity)
Treatment of Control Technolo-
gies Identified under Item
III of the Scope of Work.:
Investment
Annual Costs:
Interest + Taxes and
Insurance
.Depreciation
Operating and Maintenance
Costs (excluding energy
and payer costs)
Energy and Power Costs
Total Annual Cost
A
500,000
'•
25,000
50,000
55,000
1,000
131,000
B
500,000
25,000
50,000
55,000
17000
131,000
C
700,000
35,000
70,000
61,000.
2,000
168,000
D
750,000
37,500
75,000
64,000
7,000
183,500
Effluent C.
Effluent Constituents
Parameters (Units) Haw
ko/kkg (Pounds/Ton) Waste
Load
Resulting Effluent
Levels
Sodium Chloride
Sodium Hypochlorite
Mercury
50(100) 50(100) 50(100) 70(140)
20(40) 20(40) 20(40) ~0
<0.05(<0.1) <1 xlO"^ <7xlO~5 <7xlO"5
(<2xlO"3) ^l^xlO"4)^!-4*™"
~0
-0
o
Level A — Reduction of mercury to less than 1 x 10~° kg/kkg.
Level B — Reduction of mercury to less than 7 x 10"^ kg/kkg.
Level C — Level B + catalytic conversion of sodium hypo chlorite to sodium chloride.
Plant 09S is at this level.
Level D — Level C + evaporation and reuse of sodium chloride. No effluent except cooling
water from system. Drying sulfuric acid to other use or concentration.
243
-------
Water Effluent Trsatrrent Costs
Inorganic Chemicals
Chemical: Diaphragm Cell, Chlor-Alkalt (1810 kkg/day (2000 ton/day) Capacity)
Treatment of Control Tednnolo-
gies Identified under Item "
III of the Scope of Work:
Investment
Annual Costs:
Interest + Taxes and
Insurance
Depreciation
Operating and Jyiaintenance
Costs (excluding energy
and power costs)
Energy and Power Costs
Total Annual Cost
A
45,000
2,250
4,500
24,000
30,750
B
65,000
3,250
6,500
224,000
1,000
234,750
C
495,000*
3,250
6,500
224,000
1,000
234,750
D
1,500,000
75,000
150,000
224,000
1,000
450,000
Effluent Quality:
Effluent Constituents
Parameters (Units)
kg/kkg (Pounds/Ton)
Calcium Carbonate sludge
Sodium Hypochlorite
Spent Sulfuric Acid
Chlorinated Hydrocarbons
Sodium Chloride
Sodium Hydroxide
Kaw
Waste
Load
12.25(24.5)
7.5(15)
4(8)
0.7(1.4)
25.5(51)
22(44)
Insulting
Effluent
.Levels
0
7.5(15)
4(8)
0.7(1.4)
25.5(51)
22(44)
0
7.5(15)
0
0
5(10)
4.5(9)
0
0
0
0
5(10)
4.5(9)
0
0
0
0
0
0
Level A — Settling Pond.
Level B — Chlorinated hydrocarbons to disposal pit + sulfuric acid to sales, neutralization of
sodium hydroxide and brine returned to system.
Level C — Installation of chlorine burning hydrochloric acid plant for chlorine tail gas.
Hydrochloric acid value equal to cost.
Level D — Non-contact cooling substituted for barometric condensers - rough estimate.
*Cost of installation — 0 contribution to cost — see Level C note.
244
-------
attaining no discharge of process waste water pollutants are
proximately $0.55/kkg ($0.50/ton) of product. For new facilities
the cost would be considerably less, since non-contact condensers
should be used in place of barometric condensers.
Additional energy requirements are negligible.
Hydrochloric Acid
During normal operation the chlorine-burning hydrochloric acid
manufacturing process has no water-borne wastes, startup wastes
are less than 0.5 kg/kkg (1.0 Ib/ton) of product and are
typically neutralized in sodium hydroxide solutions. Cost
effectiveness information is given in Table 51 using plant 121 as
a model. Addition of a small sodium hypochlorite destruction
vessel plus a pump and transfer line for reuse in the chlor-
alkali eliminates the process waste water discharge from the
process. Total cost for zero effluent attainment is $0.33/kkg
($0.30/ton) of product, while the incremental cost for going from
typical to zero effluent treatment levels is $0.055/kkg
($0.05/ton). Additional energy requirements are negligible.
Hydrofluoric Acid
Hydrofluoric acid production, like that of the other mineral
acids, generates a very low water-borne waste load. Good
engineering, maintenance and •housekeeping reduces the waste
effluent to 0.5 kg/kkg (1.0 Ib/ton) or less. A complete recycle
zero discharge plant (152) of 27 kkg/day (30 ton/day) capacity
and 15 years age, is chosen for cost effectiveness calculations
as given in Table 48, column 4 (alternate B).
The large cost differential between Level C and Level B shows
that two different approaches make a substantial difference in
the costs involved. Plant Oil follows stoichiometric use of
sulfuric acid, thereby eliminating $30,000 neutralization
chemical costs per year. It handles calcium sulfate and calcium
fluoride dry by hauling to a land dump, thereby eliminating pond
settling and dredging costs for another $70,000/yr differential.
In-process changes account, therefore, for a $7.70/kkg ($7/ton)
difference in treatment costs.
Total cost to achieve no discharge of process waste water
pollutants from plant Oil is $17.60/kkg ($16/ton) and for plant
152 is $14.30/kkg ($13/ton). The greatest portion of this cost
is for handling and disposal of solid calcium sulfate, which has
to be done in all plants.
Additional energy required for going from base level treatment to
closed cycle operation is negligible. An additional 7.5 kw-hr
(10 hp-hr) is allowed for pumping from collection ponds back to
the system. This gives 5.3 x 107 kg cal (2.10 x 10* BTU) or
245
-------
TABLE 51..
Water Effluent Treatment Costs
Inorganic Chemicals
Chemical: Hydrochloric Acid (36 kkg/doy (40 tons/day) Capacity)
Treatment of Control Technolo-
gies Identified under Item
III of the Scope of Work:
Investment
Annual Costs:
Interest + Taxes and
Insurance
Depreciation
Operating and Maintenance
A
10,000
500
1,000
2,000
B*
10,000
500
1,000
2,000
c
15,000
750
1,500
2,000
D
15,000
750
1,500
2,000
Costs (excluding energy
and power costs)
Energy and Power Costs ~0 ~0 ~0 —0
Total Annual Cost 3,500 3,500 4,250 4,250
Effluent Quality:
j
Effluent Constituents
Parameters (Units) Raw
(PoundsAon) Waste Resulting Effluent
Load Levels
Chlorine & Hydrogen 0.5(1) 0.75(1.5) 0.75(1.5)* 0 0
Chloride
Levels A and B — Neutralization in sodium hydroxide solution followed by discharge to
surface water.
Levels C and D — Destruction of sodium hypochlorite in small pond or vessel and use of
sodium chloride solution in chlor-alkali system. Chlorine-burning
hypochloric acid units are always located in chlor-alkali complexes.
This corresponds to exemplary plant operation with wastes only during startup. Level I
guideline recommendation modelled to C.
246
-------
TABLE 52.
Water Effluent Treatment Costs
Inorganic Chemicals
Chemical: Hydrofluoric Acid (36 kkg/day (40 tons/day) Capacity)
Treatment of Control Technolo-
gies Identified -under Item
III of the Scope of Work: A
Investment 0
Annual Costs:
Interest + Taxes and 0
Insurance
Depreciation
Operating and Maintenance
Costs (excluding energy
and power costs)
Energy and Power Costs
B*
30,000
1,500
0 3,000
50,000 52,000
Total Annual Cost
Effluent Quality:
Effluent Constituents
Parameters (Units) Kaw
kg/kf<9 (Pounds/Ton) Waste
Load
50,000 56,500
Alternate
n g**
50,000 75,000
2,500 3,750
5,000 7,500
60,000 165,000
1,000 5,000
68,500 181,250
Resulting Effluent
Levels
3650(7300)
110(220)
62.5(125)
2.5(5)
12.5(25)
12.5(25)
0
0
0.5(1)
2.5(5)
12.5(25)
12.5(25)
0
0
0.25(0.5)
0.25(0.5)
0
0
0
0
0
0
0
0
0
0
0
- 0
0
0
Calcium Sulfate
Sulfuric Acid
Calcium Fluoride
Hydrogen Fluoride
HydrofluorosiMcic Acid
Silicon Dioxide
Level A — Land dumping of calcium sulfate, minimizing acid by operating near stoichio-
metry requirements. Costs are all for trucking of calcium sulfate, calcium fluoride
and contained sulfuric acid to land dump.
Level B — Similar to Exemplary Plant 011 of this study.
Level C — Closed loop extension of Oil •
'Exemplary plant operation. Level I guideline recommendation based on modelling to
Level C, or equivalent to alternate Level B.
'Exemplary closed loop plant 152 (27 kkg/day).
247
-------
795/1/yr (210 gal/yr) of fuel oil. Total industry additional
energy requirements are 8.30 x 10e kg cal (3.3 x 10* BTU).
Hydrogen Peroxide
a) Organic process
The waste water effluent resulting from the manufacture of
hydrogen peroxide by the organic process contains waste hydrogen
peroxide plus an organic solvent. The nature of this solvent is
regarded as a trade secret.
Cost effectiveness information is developed in Table 53 for
exemplary plant 069, a twenty year old, 85 kkg/day (94 ton/day)
facility.
Estimated additional cost to attain zero waste discharge is
approximately $1.10/kkg ($1.00/ton) of hydrogen peroxide.
Additional energy requirements are negligible.
b) Electrolytic process
Hydrogen peroxide may be produced using an electrolytic process.
Twenty year old plant 100 serves as the basis for the cost
effectiveness information shown in Table 54.
Elimination of the process waste water discharge from this plant
would cost approximately $0.28 to $0.83/kkg ($0.25 to $0.75/ton)
of product produced.
Additional energy required would be 2.2 x 10s kg cal (8.7 x 10*
BTU) .
Nitric Acid
There is no water-borne waste from the nitric acid manufacturing
process* nor is there usually any contribution from air pollution
treatment equipment. Only leaks, spills, monitoring and con-
tainment costs are involved.
For seven year old, 281 kkg/day (310 ton/day) plant 114, there
are no effluent waste streams except boiler and cooling tower
blowdowns. These are over 378,500 I/day (100,000 gal/day) in
volume. Ancillary streams, however, are excluded from process
waste water guidelines. Since no cost figures are available for
nitric acid, they are estimated to be the same as those for
sulfuric acid isolation and containment, $160,000. Applying this
cost to the 288 kkg/day (320 ton/day) plant gives $0.24/kkg
($0.22/ton) cost for isolation and containment of leaks and
spills. No energy addition is involved.
248
-------
TABLE 53 \ '
Water Effluent Treatrrent Costs
Imrganic Chemicals
Chemical: Hydrogen Peroxide (Organic Process) (85 kkg/day (94 tons/day) Capacity)
Treatment of Control Technolo-
gies Identified undar Item
III of the Scope of Work:
Inves-teant
Annual Costs:
Interest + Taxes and
Insurance
Depreciation
Operating and Maintenance
Costs (excluding energy •
and power costs)
Energy and Power Costs
Total Annual Cost.
Effluent Quality^
Effluent Constituents
Paransters' '(Units) Haw
kgAkg (PouwdsAon) Waste
Load
Organics 0.25(0.5)
Hydrogen Peroxide 20(40)
A .B*
23,000 53,000
1,150 2,650
2,300 5,300
3,000 3,000
-0 -0
6,450 10,950
C
200,000
10,000
20,000
5,000
~o
35,000
D
0
10,000
20,000
5,000
-0
35,000
Resulting . Effluent
Levels
0.1(0.2) 0.025(0.05)
5(10) 5(10)
0
0
0
0
Level A — Reduction of hydrogen peroxide with scrap iron, organics removal by mechanical
separation.
Level B — Level A+ improved organics removal and spill containment.
Level C —• Closed loop process water, non-contact cooling water only effluent.
Not exemplary plant, modeled.
249
-------
54.
Water Effluent Treateent Costs
. Inorganic Chemicals
Chemical: Hydrogen Peroxide - Electrolytic (12 kkg/day (13.2 ton/day) Capacity)
Treatment of Control. Ifechnolo-
gies Identified under Item
III of the Scope of Vfork:
A
Investment
Annual Costs.:
Interest + Taxes and
Insurance
Depreciation
Operating and Maintenance
Costs (excluding energy
and power costs)
Energy and Power Costs
Total Annual Cost
Effluent Quality:
Effluent Constituents
Paran-eters (Units)
(Pounds/Ton) Waste
Load
.B , C D
12,500 15,000
625
1,250
1,600
-0
3,475
750
1,500
2,000
1,000
5,250
Resulting Effluent
Levels
Sodium Sulfate
Ammonium Sulfate
0.75(1.5) 0.75(1.5) 0.75(1.5) -0
0.75(1.5) 0.75(1.5) 0.75(1.5) -0
Level A — There is no typical plant.
Level B — Present plant operation
Level C — Distillation to dryness 1136 liters/day (300 GPD)
250
-------
Potassium Metal
There are no process, air pollution or ancillary water wastes
involved in the production of potassium metal.
Potassium Chromates
Potassium dichromate is made from the reaction of sodium
dichromate with potassium chloride. There is none of the massive
ore waste present as in the sodium dichromate process. The only
water-borne wastes from the exemplary 25 year oldf ,13-5 kkg/day
(15 ton/day) plant 002 are from once-through cooling water used
on the barometric condensers. Replacement of these condensers
with non-contact heat exchangers, as planned for 1974, will
eliminate the discharge of process waste water pollutants from
this plant. cost for this conversion is estimated at $60,000.
See Table 55.
The treatment differential in going from base Level A to zero
discharge costs $5.12/kkg ($4.65/ton) of potassium dichromate.
Energy requirements for pumps, filters, centrifuges, and other
equipment are taken as 7.5 kw-hr (10 hp-hr) or 5.3 x 10* kg
cal/yr (2.1 x 108 ETU/yr). Entire industry additional energy is
estimated at the same value%
Potassium Sulfate
The treatment and control cost effectiveness values for potassium
sulfate based on plant 118 are developed in Table 56.
Costs for going from base treatment to zero effluent is $2.38/kkg
($2.16/ton) of potassium sulfate.
There is a relatively high energy recovery process with 6.7 x
10io kg cal (2.65 x 10« BTU) or 1,000,000 1 (265,000 gal) of fuel
oil energy per year. For the entire industry the additional
energy requirement is 1.72 x 10" kg cal (6.8 x 10** BTU).
Sodium Bicarbonate
Water-borne wastes from sodium bicarbonate facilities are small.
Using plant 166 as a model, cost effectiveness values are
developed in Table 57. Reducing the bicarbonate wastes -to zero
should be virtually cost free since current product losses should
cover expenses,
There are no significant new energy requirements.
251
-------
1SHLE 55*
Water Effluent Treatment Costs
Inorganic Chemicals
Chemical: Potassium Chromare (13.5 kkg/day (15 tons/day) capacity)
•Ereatrrsnt of Control Tedmolo-
gies Identified under Item
III of the Scope of Work:
Investment
Annual Costs:
Interest + Taxes and
Insurance
Depreciation
Operating and Maintenance
Costs (excluding energy
and power costs)
Energy and Power Costs
Total Annual Cost
Effluent Quality:
Effluent Constituents
Pararteters (Units) Raw
kg/kkg (PoundsAon) Waste
load
Sodium Chloride 400(800)
Filter Aid 0.85(1.7)
Potassium Dichromate ~Q.5(~1]
A
20,000
1,000
2,000
0
0
3,000
B*
50,000
2,500
5,000
10,000
1,000
18,500
C
110,000
5,500
11,000
10,000
1,000
27,500
D
110,000
5,500
11,000
10,000
1,000
27,500
Resulting Effluent
Levels
400(800)
~0.05(~Q.l)
~0.5(~1)
0
0
~o.5(~n
0
0
-0
0
0
-0
Level A — Discharge of all water to settling pond to remove filter aid.
Level B — Centrifuge, filter, pumps, piping and installation for sodium chloride and filter
aid removal. Salt value has been assumed zero.
Level C — Non-contact heat exchangers installed.
'Exemplary plant. Level 1 guidelines recommendations modelled to Level C, plans for
1974 for exemplary plant.
252
-------
1BBLE 56.
Water Effluent Treatment Costs
Irr>rganic Chemicals
Chemical: Potassium Sulfate (454 kkg (500 tons) per day Capacity)
Treatment of Control OTschnolo-
gies Identified under Item
III of the Scope of Work:
Inves -brant
Annual Costs:
Interest + Taxes and
Insurance
Depreciation
Operating and Maintenance
Costs (excluding energy
and power costs)
Energy and Power Costs
''total Annual Cose
A
40,000
2,000
4,000
10,000
~0
16,000
B
700,000
35,000
70,000
124,000
166,000
395,000
C
700,000
35,000
70,000
124,000
166,000
395,000
D
700,000
35,000
70,000
124,000
166,000
395,000
Effluent Quality r
Effluent Constituents
Paraireters (Units) Raw
(Pounds/Ion) Waste Resulting Effluent
Load Levels
Ore Muds 15(30) 0 0 0 0
Waste Liquor 2000(4000) 2000(4000) 000
Level A — Pond settling of muds. Discharge of dissolved solids to surface water.
Level B — Evaporation to recover liquor chemicals and water + Level A value of recovered
chemicals not deducted from costs. Water value is also not deducted.
253
-------
Cost effectiveness values are developed using these two technol-
ogies in Table 58.
Additional costs for zero discharge of wastes to surface water
are approximately $0.55/kkg ($0.50/ton) of product. For deep-
welling disposal alone, costs for zero waste effluent are
$1.76/kkg ($1.60/ton)produced. Additional energy requirements,
primarily for calcium chloride recovery, are high. Estimated
requirements for plant 166 are 3.15 x 10" kg cal/yr (1.25 x 101Z
ETU/yr) or for the entire industry 1.26 x 10*2 kg cal/yr (5.0 x
BTU/yr) . Without calcium chloride recovery, about 1.25 x
kg cal/yr (5.0 x 10*2 BTU/yr) for plant 166 or 5.0 x 10*o kg
cal/yr (2.0 x 10" BTU/yr) for the industry, would be needed for
deep welling.
Sodium Chloride
a) Solar evaporation process
It has been recommended that concentrated magnesium-rich residual
brines or bitterns from solar salt manufacture be stored and
eventually recovered for their chemical value. Taking Plant 059
as a model, cost effectiveness values are developed in Table 59.
One 146 ha (360 ac) pond is needed each year. While this storage
capacity is available for the next five to ten years, obviously
it cannot go on indefinitely. Use of these valuable mineral
deposits should be made in the near future. Storage costs for
solar salt bitterns for Plant 059 are $2.42/kkg ($2.20/ton) of
product.
Additional energy requirements are negligible.
b) Solution brine-mining process
Unlike the solar salt industry where all wastes are stored or
disposed of in surface ponds, salt producers using the
brine-mining-process get their salt from underground deposits and
return most wastes to the mine deposit.
Exemplary plant 030, a 49 year old, 1,000 kkg/day (1,100 ton/day)
facility is used for cost effectiveness developments in Table 60.
Complete elimination of process wastes in the plant effluent
would cost, for a new plant, approximately $0,28/kkg ($0.25/ton)
of product. This assumes plant 030 technology plus initial
installation of non-contact final condensers. Conveying and
packing losses may recovered dry and either reused or land (or
well) disposed.
Elimination of all but 1 kg/kkg (2 Ib/ton) waste from plant 030
would cost approximately $0.55/kkg ($0.50/ton) of product.
256
-------
58.
/•
Water Effluent Trsabrent Costs •
Inorganic Chemicals
Chemical: Soda Ash (2520 kkg/day (2800 tons/day) Capacity)
[Treatment of Control Tachnolo- '
gies Identified under Item
HI of the Scope of Wade: ABC D
Investment 500,000 21,500,000 27,500,000 27,500,000
Annual Costs:
Interest + Taxes and 25,000 1,075,000 1,375,000 1,375,000
Insurance
. Depreciation "' 50,000 2,150,000 2,750,000 2,750,000
Operating and Maintenance 375,000 3,175,000 3,675,000 3,675,000
Costs (excluding energy
and power costs) • ' .
Energy and Power Costs - 800,000 1,000,000 1,000,000
Total Annual Cost 450,000 (1,080,000) 520,000 520,000
Profit
Effluent Quality J
Effluent Constituents
Parameters (Units) Raw
kg/kkg (Pounds/Ton) Waste Resulting Effluent
Load Levels
Calcium Chloride 1100(2200) 1100(2200) 900(1800) 0* 0*
Sodium Chloride 500(1000) 500(1000) 500(1000) 0* 0*
Calcium Carbonate 85(170) -0 -0 0* 0*
Calcium Oxide 135(270) 25(50) 25(50) 0* 0*
Calcium Sulfate 31(62) 2.5(5) 2.5(5) 0* 0*
Ash and cinders 40(80) -0 -0 0* 0*
Silicon Dioxide 58^(117) ~0 -0 0* 0*
Level A — Settling ponds
Level B — Level A + evaporation of 20% of stream to recover calcium chloride for sale at
$44/kkg ($40/ton) — 8/280,000 value.
Level C — Level B + deep well disposal.
*No. surface water effluent.
257
-------
TABLE 59 -
Water Effluent Treatment Costs
Inorganic Chemicals
Chemical: Solar Salt (2540 kkg/day (28COtons/day) Capacity)
Txsatrrent of Control Technolo-
gies Identified under Item
III of the Scope of Work: A B C D
Investment 14,400,000 14,400,000 14,400,000 14,400,000
Annual Costs:
Interest + Taxes and 720,000 720,000 720,000 720,000
Insurance
Depreciation 1 ,440,000 1 ,440,000 1 ,440,000 1 ,440,000
Operating and Maintenance ~0 ~0 ~0 ~0
Costs (excluding energy
and power costs)
Energy s^ Power Costs ~0 ~0 ~0 ~0
Total Annual Cost 2,160,000 2,160,000 2,160,000 2,160,000
t
Effluent Quality:
Effluent Constituents
"' Paxarreters (Unitis} Baw
(Pounds/Ton) Waste Resulting Effluent
Load Levels
Bitterns 70,000(140,000) 00 0
Level A — 1 new 360 acre unlined pond per year is needed. Costs are taken from
Section VIII for unlined ponds.
258
-------
TABLE GO .
Water Effluent Treatment Costs
Inorganic Chemicals
Chemical: Sodium Chloride (Brine/Mining) (1000 kkg/day (1100 ton/day) Capacity
Treatment of Control Technolo-
gies Identified' under Item
III of the Scope of Work:
Investirient
Annual Costs:
Interest + Taxes and
Insurance
Depreciation
Operating and Maintenance
Costs (excluding energy
and pcwer costs)
Energy and Power Costs
Total Annual Cost
, A .B-
500,000
25,000
50,000
10,000
~o
85,000
C
1,000,000
50,000
100,000
10,000
-0
160,000
D
600,000
30,000
• 60,000
10,000
-0
100,000.
9
Effluent Quality:
Effluent Constituents
Pararreters (Units) Raw
kg/kkg (Pounds/Ton) Waste Resulting Effluent
Load Levels '
Sodium Chlorine 50(100) - 6(12) 1(2) ~0
Brine Sludge 2.5(5) - 0 0 ~0
Level A — No information.
Level B — Plant 030 technology, sludge returned to wells. Control system developed including
$425,000 damming, curbing, collection and pumping to wells, and $63,000 instru-
mentation and miscellaneous pumps and piping.
Level C — Level B + non-contact heat exchangers for barometric condensers.
Level D — For new plants. Elimination of conveying and packing station losses peculiar
to Plant 030.
259
-------
Negligible additional energy would be required.
Sodium Dichromate
The sodium dichromate manufacturing process produces a waste
stream containing high concentrations of suspended and dissolved
solids primarily because of the chromium treatment process used.
Two year old 149 kkg/day (164 ton/day) plant 184 is used as the
model for cost effectiveness development as shown in Table 61.
Additional cost above typical treatment is $17.60/kkg ($16/ton)
of product, of which $13.20/ ($12/ton) is already being spent in
exemplary plant 184. Evaporation to recover dissolved salts
costs $4.40/kkg ($4/ton) of product. Selling price of sodium
dichromate is $380/kkg ($345/ton).
These figures illustrate the high cost of isolating, containing,
treating and disposing harmful wastes. They also show that if
the effluent streams can be kept small, 1,317 cu m/day (348,000
gal/day) in this case, removal of dissolved salts by evaporation
is expensive, but not prohibitively so.
It is believed that, while the isolation, containment and treat-
ment facilities of exemplary plant 184 are exceptional, there are
more economical ways of achieving the same degree of chromium
reduction.
Additional energy requirements are estimated to be 2.5 x 10*° kg
cal (1.0 x 10" BTU) per year for plant 184. For the industry,
using similar treatment (which is doubtful) to to eliminate the
discharge of process waste water pollutants, the additional
yearly energy requirements would be 6.05 x 10'° kg cal (2.4 x 10"
ETC) .
Sodium Sulfate
Sodium sulfate is a by-product of sodium dichromate and other
manufacturing processes. As such, no water-borne wastes are
attributed to its production. Therefore, it is considered to be
a zero effluent-zero treatment and control chemical with no
additional energy requirements.
Sodium Metal
Sodium metal and chlorine are produced as coproducts in the Downs
Cell process. Since the chlorine produced is handled similarly
and has the same wastes as the mercury and diaphragm cell pro-
cesses, only wastes specific to the Downs Cell and sodium
production are included here. Table 62 gives the estimated cost
effectiveness values for a 58 kkg/day (65 ton/day) fourteen year
old plant (096) .
2GO
-------
61 .
Water Effluent. Treatment-Costs
Inorganic Chemicals
Chemical: Sodium Dichromate (149 kkg/day (164 tons/day) Capacity)
Treatment of Control Tedmolo-
gies Identified under Item
III of the Scope of Work: A B C D
Investment 100,000 1,000,000 1,800,000 1,800~000
Annual Costs:
Interest + Taxes and 5,000 5,000 90,000 90,000
Insurance
Depreciation "; 10,000 100,000 180,000 180,000
Operating and Maintenance ^0 560,000 610,000 610,000
Costs (excluding energy
and power costs)
Energy and Power Costs ~0 4,000 64,000 64,000
Total Annual Cost 15,000 669,000 944,000 944,000
-Effluent Quality:.
Effluent Constituents
Paranaters (Units) Raw
(Pounds/Ton) Waste Eesulting Effluent
Load Levels
Total Suspended Solids 900(1800) 0.125(0.25) 0.125(0.25) -0 ~0
Total Dissolved Solids 88.5(177) 88.5(177) 88.5(177) ~0 ~0
Chromium 6 - - 0.0001(0.0002) -0 -0
Level A — Settling pond.
Level B — Segregation and chemical treatment for chromium-6. Pond settling and discharge
of clear effluent to surface water.
Level C — Level B + evaporation to recover dissolved sodium chloride. Recovered sodium
chloride costed as zero value. Closed loop operation.
26T
-------
62.
Wat-ar Effluent Treatment Costs
Inorganic Chemicals
Chemical: Sodium Metal (58 kkg/day (65tons/day) Capacity)
Treatment of Control Technolo-
gies Identified under Item
III of the Scope of Vibrk:
Investment
Annual Costs:
Interest + Taxes and
Insurance
Depreciation
Operating and Maintenance
Costs .(excluding energy
and power costs)
Energy and Power Costs
Total Annual Cost
A
0
0
0
4,000
-0
4,000
.B
400,000
20,000
40,000
4,000
~o
64,000
C
700,000
35,000
70,000
10,000
-0
115,000
D
0
35,000
70,000
10,000
~o
115,000
Effluent Quality;
Effluent Constituents
Parameters (Units)
kg/kkg (Pounds/Ton)
Sodium Chloride
Misc. Alkaline Salts "
Bricks, Anodes, Other
Solids
Raw
Waste
load
57.5(115)
30(60)
.Resulting Effluent-
levels
57.5(115) 57.5(115) ~0
30(60) 30(60) ~0
000
Level A — Disposal of salts plus solids.
Level B — Facilities for separating salts from solids.
Level C — Containment, isolation and return of salts to brine system.
~0
~0
262
-------
Costs for plant 096 to attain a zero water-borne waste effluent
are $2,47/kkg ($2.25/ton) of sodium above initial expenditures of
$3.30 to $4.40/kkg ($3 to $4/ton) of sodium, which is currently
selling for $412/ kkg ($375/ton).
Additional energy costs should be negligible.
Sodium Silicate
The wastes from the sodium silicate manufacturing process are
relatively small and closed loop operation has been achieved in
plant 072.
For the purpose of developing cost effectiveness data plant 134
has been selected for Table 63 calculations. This plant is a ten
year old, 72 kkg/day (80 ton/day) facility. Control and
treatment costs are approximately $1.00/kkg ($0.90/ton) of
product.
Additional energy costs using this approach are 3.5 x 10 9 kg cal
(1U x 1010 BTU). For the total industry, additional energy
requirements are 8.4 x 10*° kg cal (3.32 x 10" BTU).
A second approach using only Level A treatment and closing the
loop bypasses both the energy requirements and most of the1 cost.
This approach is used in-plant 072. Treatment costs for this
approach would be approximately $0.22/kkg ($0.20/ton) of product.
Costs for both approaches are reasonable. In view of the energy
advantage for plant O72's approach, this recycle method should be
favored.
Sodium Sulfite
The wastes from the sodium sulfite processes are essentially
sodium sulfite. Table 64 gives the cost effectiveness values for
plant 168, a fifteen year old installation.
Costs for reducing the waste water discharge from plant 168 to
zero are approximately $2.75/kkg ($2.50/ton) of product. If
recovery cf sodium sulfite is directed at the same stream which
is now treated and directly discharged, there is a potential for
$25,000/yr profit. Plants not now treating or recovering sodium
sulfite should explore this approach.
Additional energy required is approximately 1.62 x 10^ kg cal/yr
(6.4 x 109 ETU/yr) or 24,200 1 (6'400 gal) of fuel oil /yr. For
the entire industry this would be 2.92 x 1010 kg cal (1.16 x 10lo
BTU) .
263
-------
TABLE 63.
Water Effluent Treatrrent Costs
Inorganic Chemicals
Chemical: Sodium Silicate (72 kkg/day (80 tons/day) Capacity)
Treatment of Control Technolo-
gies Identified under Item
III of the Scope of Work:
Investment
Annual Costs:
Interest + Taxes and
Insurance,
Depreciation
Operating and Maintenance
Costs (excluding energy
and power costs)
Energy and Power Costs
Total Annual Cost
A
26,000
1,300
2,600
1,000
-0
4,900
.B*
42,000
2,106
4,200
9,000
—
15,300
C*
62,000
3,100
6,200
10,000
10,000
29,300
D
62,000
3,100
6,200
10,000
10,000
29,300
Effluent Quality:
Effluent Constituents
Paraiteters (Units) Raw
kgAkg (PoundsAon) Waste Besultiag Effluent
Load Levels
Sodium Silicate
Sodium Sulfate
Filter Aids
Sand
Sodium Hydroxide
Level A — Settling pond only.
Level B — Settling pond plus neutralization (existing good plant).
Level C — Evaporation to remove and recover dissolved solids + Levels A and B treatnTent,
Sodium silicate recovered (exemplary plant).
2(4)
2.5(5)
2(4)
0.5(1)
0.5(1)
2(4)
2.5(5)
0
0
0.5(1)
2(4)
2.5(5)
0
0
0
0
0
0
0
0
0
0
0
0
0
*Note Level C is exemplary plant level in this table.
264
-------
E 64.
Water Effluent Treatrrent Costs
Inorganic Chemicals
Chemical: Sodium Sulfite (45 kkg/day (50 ton/day) Capacity)
Treatment of Control Technolo-
gies Identified under Item
III of the Scope of Work:
Investnvent
Annual Costs:
Interest + Taxes and
Insurance
Depreciation
Operating and Maintenance
Costs {excluding energy
and power costs)
Energy and Power Costs
Total Annual Cost
Effluent Quality:
Effluent Constituents
Pararreters (Units) Raw
kQ/fckg (Po-vi-ids/Ton) Waste
Load
Sodium Sulfate
Sodium Sulfite 30.5(61)
A
0
0
0
0
0
0
B
250,000
12,500
25,000
10,000
2,000
49,500
. c
275,000
13,750
27,500
12,000
7,000
47,750
D
150,000
7,500
'15,000
5,000
6,000
^25, 000) Profit
Resulting Effluent
Levels
-
30.5(61)
29(58)
1.5(3)
0
0
0
0
Level A — No treatment — typical for industry.
Level B — Full treatment system, but dissolved solids still discharged.
Level C — Level B + evaporation recovery and sales of recovered product. Product value
$12,500.
Level D — Isolation and containment parts of complete system of Level B + evaporation to
recover sodium sulfite. Product value is $58,500.
265
-------
Sulfuric Acid
The sulfuric acid (sulfur- burning) manufacturing process has no
process wastes. The only water-borne wastes result from leaks,
spills, air pollution control equipment, and ancillary operations
such as cooling tower blowdowns and ion-exchange regenerants.
Since cooling tower blowdowns and ion-exchange regenerants are
not considered to be process waste water, they are not included
here. Air pollution control equipment costs are presented for
informational purposes.
Regen plants for making sulfuric acid from waste or spent acid
are not covered in this study but are included in cost
effectiveness development for informational purposes.
Exemplary sulfur-burning plant 141, a three year old, 360 kkg/day
(UOO ton/day) plant, was used as the model in Table 65.
Costs are less than $0.10/kkg ($0.10/ton) of product. Additional
energy is negligible.
Titanium Dioxide
a) Chloride process
Most chloride processes for titanium dioxide production use
either rutile or "synthetic rutile" ore. One plant uses lower-
grade ores but for the purposes of this cost effectiveness
discussion, this process is considered to be on-site
benef iciation plus a "synthetic rutile" process.
Currently, chloride process wastes are treated or disposed of by
complete neutralization, deep-welling and ocean barging. For
companies already ocean barging, cost run $5, 50 - $11 kkg ($5 to
$10 per ton) of titanium dioxide product. For those starting
barging a location further from the ocean, or requiring extensive
shore facilities, the costs may range from $11 to $22/kkg ($10 to
$20/ton) .
Deep-welling costs run from $2.20 to $5.50/kkg ($2 to $5/ton) of
titanium dioxide product. Complete neutralization, on the other
hand, is much more expensive. Table 6.6 shows the cost
effectiveness development for this approach using ten year old 67
kkg/day (74 ton/day) exemplary plant 009 as the model,
Complete neutralization which is now done by plant 009 costs
$40/kkg ($36/ton) differential over base treatment Level A.
Reduction to virtually zero discharge of wastes costs $71/ kkg
($64/ton) of product. Titanium dioxide sells for $605 to
$627/kkg ($550 to $570/ton) .
Additional energy costs are roughly estimated to be 1,3 x 10*o x
10»° kg cal (5.0 x 10*° BTU) for plant 009 and 1.7 x 10" kg cal
266
-------
65.
Water Effluent Treatmsnt Costs
Inorganic Chemicals
Chemical: Sulfuric Acid (Sulfur Burning)(360 kkg/day (400 tons/day) Capacity)
Treatment of Control Technolo-
gies Identified under Item
III of the Scope of Work:
Investment
Annual Costs:
Interest + Taxes and
Insurance
Depreciation
Operating and Maintenance
Costa (excluding energy
and power costs)
Energy and Power Costs
A
50,000
2,500
5,000
-0
-0
7,500
B
100,000
5,000
10,000
-o
~0
15,000
C
160,000
8,000
16,000
~o
~0
24,000
D
160,000
8,000
16,000
~o
~o
24,000
Total Annual Cost
Effluent Quality t
Effluent Constituents
Parameters (Units) Raw
Waste Resulting Effluent
Load Levels
Spills, Leaks 1(2) 0.5(1) 000
Closed Cycle System
Level A — Typical diking and containment.
Level B — Good isolation and containment + Level A.
Level C — Lined containment emergency pond — 0.4 hectare (1 acre) + Level A and B.
267
-------
TABLE 66'.
Water Effluent Treatment Costs
Inorganic Chemicals
Chemical: Titanium Dioxide (Chloride Process),67 kkg (74 ton) per day basis
Treatment of Control Technolo-
gies Identified under Item
III of the Scope of VSork:
Investment
Annual Costs:
Interest + Taxes and
Insurance
Depreciation
Operating and Maintenance
Costs (excluding energy
and power costs)
Energy and Power Costs
Total Annual Cost
A
300,000
15,000
30,000
10,000
~0
55,000
B
4,000,000
200,000
400,000
390,000
10,000
1 ,000,000
C
5,300,000
265,000
530,000
890,000
45,000
1,730,000
D
5,300,000
265,000
530,000
890,000
45,000
1 ,730,000
Effluent Quality:
Effluent Constituents
Pararreters (Units) Raw
lc§/kkg (PoundsAon) Waste
Load
Iron Hydroxides 65(130)
Other metal oxides 65(130)
Ore 138(276)
Titanium hydroxides 25(50)
Hydrochloric Acid 227(454)
Titanium Dioxide 40.5(81)
Coke 23(46)
Soluble Chlorides and
su I fates
Leval A — Pond settling.
Level B — Complete chemical treatment facility + land dumping of solid waste.
Level C — Level B + specialty unit demineralization + evaporation of regenerant solution
Level D — Same as Level C.
Resulting Effluent
Levels
65(130)
65(130)
~o
29(58)
227(454)
~o
~o
-
~0
~o
-0
~0
~o
-0
~0
315(630)
~o
~o
~o
~0
~o
-0
~o
-0
~o
-o
~o
-0
~0
~o
-o
~o
268
-------
(6.75 x 10" BTU) for the entire industry using the same
treatment.
b) Sulfate process
The sulfate process for producing titanium dioxide has the
heaviest water-borne waste load per ton of product of all the
processes of this study. Of the approximately three kkg
waste/kkg of product, two kkg are sulfuric acid. The model plant
used is plant 142, a twenty-seven year old 108 kkg/day (120
ton/day) facility. Cost effectiveness is developed in Table 67.
Additional costs in going from typical Level A to virtually
complete elimination of water-borne wastes are $106/kkg ($96/ton)
or 10.50/kg (4.80/lb) of titanium dioxide produced. Going to
Level C costs $90/kkg ($82/ton) or 9.00/kg (4.1«Vlb).
This is compared to $8,80 to $11.0/kkg ($8 to $10/ ton) for ocean
barging of strong acid wastes. Adding Level E costs of
approximately $ll/kkg ($107ton) to this gives about $22/kkg
($20/ton) for removal of acidity and the largest portion of the
wastes. Ocean barging, as mentioned for the chloride process,
can range for new plants (or old plants not now using this
disposal means) up to $33/kkg ($40/ton) or $44/kkg ($40/ton)
overall waste costs. Thus, ocean barging costs about one-fourth
to one-half that of complete neutralization.
Acid recovery is another attractive approach. Using a current
EPA-support pilot plant as model for acid recovery, cost effect-
iveness is developed in Table 68. Additional costs for this
approach are $53/kkg ($48/ton) of titanium dioxide produced for
practically zero water-borne waste eliminating Level D. Without
demineralization, additional costs above Level A are $37.50/kkg
($34/ton) or about onehalf that for complete neutralization.
Required additional energy for complete neutralization plus
demineralization and evaporation of regenerant is 4.15 x 1010 kg
cal/yr (4.0 x 10* BTU/yr) for plant 142 and 1.35 x 10" kg cal/yr
(5.35 x 10" BTU/yr) for the industry (sulfate process).
Similar values for acid recovery are 1,6 x 10" kg cal (6.3 x 10"
BTU) for plant 142 and 1.32 x 10^2 kg cal (5.2 x 10*z BTU) for
the industry.
269
-------
TABLE 67-
Water Effluent Treatmsnt Costs
ILnorganic Chsnicals
Chemical: Titanium Dioxide (Sulfate Process), 108 kkg (120 ton) per day basis
Treatment of Control Technolo-
gies Identified under Item
III of the Scope of Work:
Investrtient
Annual Costs:
Interest + Taxes and
Insurance
Depreciation
Operating and Maintenance
Costs (excluding energy
and power costs)
Energy and Power Costs
Total Annual Cost
A
100,000
5,000
10,000
65,000
~0
80,000
B
150,000
7,500
15,000
400,000
~0
422,500
C
11,200,000
560,000
1,120,000
2,220,000
11,000
4,011,UUO
D
11,500,000
575,000
1,150,000
2,350,000
45,000
4,120,000
Effluent Quality:
Effluent Constituents
Parameters (Units)
(PoundsAon) Waste Resulting Effluent
Load Levels
SulfuricAcid 2025(4050) 2025(4050) W5(3490) _0 -0
Iron Sulfate 387(774) 387(774) 370(740) ~0 -0
Aluminum Sulfate 270(540) 270(540) 260(520) -0 -0
Magnesium Sulfate 220(440) 220(440) 210(420) ~0 -0
Other metal suflates 35(70) 35(70) 35(70) ~0 ~0
Sol id Wastes 210(420) 20(40) 20(40) ~0 ~0
Soluble Calcium Sulfate - 265(530) ~0
Level A — Settling Pond
Level B — Level A + neutralization of weak acid stream.
Level C — Full neutralization.
Level D — Level C + specialty system demineralization + evaporation of regenerant solution.
270
-------
68*
Watar Effluent TreatHisnt Costs (Acid Recovery Option)
Inorganic Chemicals
Chamical: Titanium Dioxide (Sulfate Process)J08kkg (120/ton) per day basis
Treatment of Control Technolo-
gies Identified under Xtera
III of the Scope of Work: A B C D
Investeant 100,000 150,000 4,000,000 5,500,000
Annual Costs:
Interest + Taxes and 5,000 7,500 200,000 275,000
Insurance
Depreciation 1,000 15,000 400,000 550,000
Operating and Maintenance 65,000 400,000 500,000 850,000
Costs (excluding energy
and power costs)
Energy and Power Costs -0 ~0 400,000 445,000
Total Annual Cost Vt,000 422,500 1,500,000 2,120,000
Effluent Quality:
Effluent Constituents
Paraireters (Units) Raw
(PoundsAon) Waste Resulting Effluent
Load Levels
SulfuricAcid 2025(4050) 2025(4050) 1745(3490) ~0
Iron Sulfate 387(774) 387(774) 370(740) ~0 -0
Aluminum Sulfate 270(540) 270(540) 260(520) ~0 -0
Magnesium Sulfate 220(440) 220(440) 210(420) ~0 ~0
Titanium Sulfate 180(360) 180(360) 130(260) -0 ~0
Other metal sulfates 35(70) 35(70) 35(70) -0 ~0
Solid Wastes 210(420) 20(40) 20(40) -0 ~0
Soluble Calcium Sulfate - ~200(~400) ~0
Level A — Settling Ponds
Level B — Level A + weak acid stream neutralization.
Level C — Level B + acid recovery facilities.
Level D — Level C + specialty system demineralization + evaporation of regenerant solution,
271
-------
Summarizing the costs for rough comparison purposes gives:
Cost/kkg (Cost/ton)
Method Titanium Dioxide
Ocean barging and weak acid $22 ($20)
neutralization
Acid recovery $UU ($40)
Total neutralization $88 ($80)
Overlaps in costs can occur depending on specific circumstances.
Since most of the neutralization products are insoluble calcium
sulfate and metallic oxides and hydroxides, the complete neu-
tralization of sulfate process wastes is a relatively "clean"
process. Also, its simple tested technology reliability is
attractive. Acid recovery is still in the development stage for
the process described. corrosion problems are the biggest
current uncertainty. The cost of this approach is one-half that
of complete neutralization, however, and there is no reason why
technology know-how can not be brought to bear on this process.
GENERAL INFORMATION ON COST OF CONTROL AND TREATMENT SYSTEMS
Segregation of contaminated water streams from non-contaminated
streams is the first step in water-borne waste abatement. Since
the treatment costs normally depend on the volume of water to be
treated more than the amount of waste, keeping the waste water
volume small reduces costs and energy requirements. Spills,
leaks and washdowns axe small, but need to be contained and
isolated.
Ccst for segregation and containment vary depending on the size
and complexity of the plant, volume and nature of the wastes, and
the equipment employed.
Estimates of these costs based on information obtained from plant
visits are given below. In general, small chemical plants
produce 50 tons/day or less of product. However, this may vary
significantly with the particular chemical.
Isolation of wastes containing mercury and chromium costs
approximately $200,000 to $300,000. Large salt, acid and chlor-
alkali plants also fall in a similar price range for isolation
and containment costs. Older plants may be more difficult and
expensive to modify than new facilities.
272
-------
Isolation and containment costs
Purpose
isolation
Containment
isolation
Installations
Trenches and sewers
pipelines, sumps,
catch basins, tanks
and pumps
Dikes and curbing
Non-contact heat-
exchangers
Small Plants Large Plants
$ 10,000-
100,000
$ 5,000-
50,000
$ 50,000
$100,000-
300,000
$ 50,000-
200,000
$100,000-
500,000
Barometric condensers are the most common source of cooling water
contamination. Barometric condensers are now being replaced by
non-contract heat exchangers in various inorganic chemical
plants.
Chemical Treatment Systems
Equipment Costs
These systems, consisting of chemical reactors, clarifiers,
thickeners, and filters or centrifuges, are designed as integral
units for complete waste treatment. Installed equipment costs
for chemical treatment systems as a function of capacity are
summarized below:
Clarifiers
Capacity Reaction and Thick-
cu m/day eners, $
(gal/davi Tanksj^
38(10,000) 15,000 15,000
379(100,000) 25,000 40,000
3785(1,000,000) 37,500 75,000
37850(10,000,000) 50,000 200,000
Filters or
Centrifuges,
$
Total*
Costs
$
25,000
25,000
200,000
750,000
60,000
150,000
500,000
2,000,000
*Includes engineering, land preparation, and installation. Does
not include land cost, storage tanks and disposal facilities, or
other auxiliary equipment.
These costs are for light slurry loads. For heavy slurry loads,
such as for titanium dioxide wastes, overall costs are several
times greater.
Chemical Costs
The costs for chemical treatments cannot be generalized. Most of
the chemicals used, however, are for neutralizations. Chemical
treatments costs depend on the chemical used and the amount
273
-------
required, which varies with the particular situation. The unit
cost of the chemical is usually known. Whenever feasible,
neutralization of alkaline wastes is done with sulfuric acid. As
shewn in Table 69, sulfuric acid costs only 30 to UO percent as
much as hydrochloric and nitric acid. In other words,
worth of sulfuric acid will neutralize 2.5 to 3.5 times
alkalinity as a dollars worth of the other two acids.
sulfuric acid is approximately $33/Tckg ($30/ton).
a dollars
as much
Cost for
Limestone and lime are commonly used to neutralize acidic waste
streams. Limestone is the lower cost material at $7-ll/kkg ($6-
10/ton); but suffers the disadvantage of slower reaction, high
impurities, and lower obtainable pH. Lime costs are
approximately $22/kkg. Ammonia and sodium hydroxide are far more
expensive than lime or limestone, with 50 percent sodium
hydroxide at $121/kkg (SllO/ton) (100 percent basis), it can be
seen why lime is preferable in most cases.
For small usage or where solubility or character of precipitate
is important, caustic soda or ammonia may still be employed.
Neutralizations with waste acids or bases can change -the whole
cost structure. Waste sulfuric acid is often available at either
no cost or the cost of freight. Waste lime, caustic soda or
ammonia can sometimes be obtained at similar low costs.
Costs for neutralizations and other chemical reactions are simply
determined for special applications by multiplying the
cost/weight of the neutralizing or reacting chemical by the
weight stoichiometrically required. Where specific experience is
available, it may have been found that 10 to 20 percent excess
over stoichiometric quantities are needed. In rare cases,
several-fold excesses may be used to ensure complete reaction,
Settling Ponds and Vessels
Pcnds for storage, emergency discharge and containment, settling
of suspended solids, or solar evaporation, are the most commonly
employed treatment and control facility in the inorganic chemical
industry. Two categories, unlined ponds and lined ponds, are
summarized in the tables and figures of this section.
A third category, tanks and vessels such as thickeners and
clarifiers, are not widely used at present in the inorganic
chemical industry as contrasted to other chemical industries and
sanitary treatment facilities. As land becomes more costly and
unavailable and treatment and control requirements change, open
tanks and vessels may see increased use. cost information on
equipment of this type has already been given in the chemical
treatment section.
274
-------
TABLE 69* Comparison of Chemicals for
Waste Neutralization
Alkaline Wastes
Neutralizing Material
Sulfuric Acid
Hydrochloric Acid
Nitric Acid
(50° Be)
(20° Be)
(39.5° Be)
Relative
Chemical
Cost*, $
1.00
2.57
3.51
kg*** Req'dAkg Alkali**
CaCOs Ca(OH)2 NaOH
1260
2320
2100
1700
3140
2840
1580
2500
2630
Acid Wastes
_Neutrql_izing Material
Lump limestone, high Ca
Lump limestone, dolomitic
Pulv. limestone, high Ca
Oulv. limestone, dolomitic
Hydrated lime, high Ca
Hydrated lime, dolomitic
Pebble lime, high Ca
Pebble lime, dolomitic
Pulv. quicklime, high Ca
Pulv. quicklime, dolomitic
Sodium bicarbonate
Soda ash
Caustic soda (50%)
Ammonia (anhyd.)
Magnesium oxide
kg*** Req'd/kkg Acid*
Cost*, $ H2SO4
16
00
59
37
06
50
07
87
18
97
20.65
13,08
9.96
5,90
3.90
1100
940
1100
940
790
650
600
540
600
540
1730
1190
1640
350
420
HCI
1480
1270
1480
1270
1070
870
800
730
800
730
2330
1600
2200
470
560
HNO3
860
730
860
730
620
510
460
420
460
420
1350
930
1270
270
330
*Delivered cost Including freight.
**Commodity weight.
***To convert numbers to Ibs. req'd/100 Ibs alkali or acid, multiply x 0.1.
275
-------
Unlined Ponds
The costs of constructing unlined ponds differ widely depending
on the circumstances. Since they cover large areas, the cost of
the land itself is a factor. Building a 200 hectare (500 ac)
pcnd on prime industrial land may cost $1 to 5 million just for
the land itself. No provision is made in this analysis, however,
for such costs. It is assumed that the land value is not a large
pcrtion of the cost. For small ponds of less than 4 to 20 ha (10
to 50 ac) and land values of $250 to $625/ha ($100 to $250/ac),
this assumption is good, as will be seen from the magnitude of
the other costs.
Construction costs vary widely depending on the circumstances.
Use is often made of natural pits, valleys, ponds, lakes, etc.,
for minor alterations, such as damming, dike building and
leveling. Excavation is easier in some localities than ethers.
Pond size is also a major cost factor. Small ponds may be dug
and the excavated dirt used for dikes. Large ponds are usually
diked or dammed.
Assuming equal depths of two ponds, one large and one small, the
volume increases as the square while the dike length (and earth
moving) is increasing only linearly. Therefore, costs will be
developed for small ponds and then for large ones.
Small pond capital costs are given in Figure 6U.
Large pond costs developed from reference (27) are shown in
Figure 65. Undoubtedly, many of these installations made use of
natural topography (lakes, basins, etc.) to avoid as much
excavation as possible. Nevertheless, the general cost levels
and trends may be seen. As would be expected from the diking
costs varying by the square root of the area, the pond costs per
hectare above 200 ha (500 ac) change very slowly.
Lined Ponds
To avoid excessive liquid seepage, ponds are often lined with
clay, concrete or other substances. Recently, however, new
lining materials have come into use — rubber and plastic
sheeting.
Essentially, costs for pond construction are the same as for
unlined ponds except for the sheeting material and installation,
Therefore, the costs may be estimated by adding the installed
liner costs to the previously determined costs for unlined ponds.
The material costs for the lining range from $1,00 to $6,00/sq m
(10£ to 600/sq ft), depending on the material selected and the
thickness of the sheet.(30) Although thicknesses as low as 250
microns (10 mils) have been discussed,(31) the most used
thickness appears to be 750 micron (30 mils). For 750 micron (30
mils) PVC liners, the installed cost is approximately $2.00/sq m.
276
-------
s.
I'
rot- i-
POND UREA (HECTARES)
FOND AREA (ACRES)
FIGURE 64-
CAPITAL COSTS FOR SMALL UNLINED PONDS
(REFERENCE (28), (29), AND (30))
500
POND AREA (HECTARES)
IOOO 1500
POND AREA (ACRES)
FIGURE feS
CAPITAL COSTS FOR LARGE UNLINED PONDS
(REFERENCE (27))
277
-------
2000 MOO 3000 10000 20,000 JOOOO 40000
CAPACITY (CU M/WM
1000,000
CAFwrrr IOPDI
FIGURE 68
INSTALLED CAPITAL COST FOR
CARBON ADSORPTION EQUIPMENT
~ ISO
IOO
500
100,000
000
2000 3000 5000 10,000
CAPACITY (CU M/DAY)
20,000 30,000 40,000
1,000,000
CAPACITY (GPD)
10,000,000
FIGURE 69
OVERALL COSTS FOR CARBON ADSORPTION
280
-------
TABLE 70o Capital Costs for Lined Solar Evaporation
Ponds as a Function of Capacity*
Evaporation--Rainfall Differential
2 Ft.
Hectare Capital
(Acres) Costs
4 Ft.
Hectare Capital
(Acres) Costs
6 Ft.
Hectare
(Acres)
Capital
Costs
Capacity
cu m/day(GPD)
38 (10,000)
189 (50,000)
378(100,000)
945 (250,000)
1890 (500,000)
3785 (1,000,000) 220 (560) 6,650,000 112 (280) 3,700,000 74.8 (187) 2,570,000
*Ponds of 10 acres and under tanke from Figure 74; those over 10 acres taken from Figure 75.
2.2 (5.6)
11.2(28)
22 (56)
56 (140)
112(280)
150,000
420,000
820,000
1,960,000
3,700,000
1.1 (2.8)
5.6 (14)
11.2(28)
28 (70)
56(140)
95,000 0.8(1.9)
212,000* 3.7(9.3)
470,000 7.5 (18.7)
,010,000 18.7(46.7)
1,960,000 37.3(93.3)
80>000
220,000*
282,000
690,000
1,350,000
TABLE 71 ff Costs for Solar Evaporative Pond Disposal
Evaporative
Capacity
cu m/day (GPP)
38 (10,000)
379(100,000)
3785(1,000,000)
20-Year Pond Life
Cost, C/3785 liters (<:/!,000 Gal.)
Evaporation-Rainfall Differential
2 ft/yr 4ft/yr o~7t7yr
214
117
95
136
67
53
114
40
37
281
-------
treatment methods are: (1) Sodium-hydrogen zeolite dealkalizers
(2) Zeolite softeners
Estimated costs of ion-exchange operations as a function of
dissolved solids concentration are shown below:
Zeolite Softening, Sodium-Hydrogen
Total Dissolved 0/3785 1 Dealkalizer,
Solids fmq/11 (g/1QOQ gal) g/3785 1 (1/1000 gal)
200 5.7 6.a
500 10.8 9.5
750 15.0 12.2
while these values are only approximations, they do show that
zeolite "softening" or ion exchange with sodium chloride or
sodium chloride plus sulfuric acid is fairly low in cost even at
the 750 mg/1 total dissolved solids level. ion exchange does not
remove dissolved solids from waste water. Therefore, ion
exchange units produce regenerant wastes which require disposal.
With these considerations, ion exchange units are generally used
only for certain specific harmful ion situations,
Demineralization Costs
The cost of demineralization equipment itself is fairly consis-
tent for the low solids fixed bed units used for most applica-
tions. For the specialty systems described in Section VII,
particularly at solids concentrations above 1000 mg/1, the costs
are significantly higher for a given capacity. Both the special
nature of these units and the influence of the higher resin
volumes required to take the increased loading increase capital
costs. Installed capital costs can also differ greatly depending
on land availability, pretreatment facilities needed, buildings,
storage tanks, and engineering and contractor costs. The
installed capital costs developed in this section have been
adjusted using 33 percent of equipment costs for installation and
six percent increase per year in equipment costs. All values are
in 1973 dollars. They do not include resin costs which are
covered in operating costs. Values for capital costs were taken
from literature references. Average values are plotted in Figure
70,
Generally, installed capital costs for conventional
demineralization units are about one-half the cost for reverse
osmosis installations with similar capacities,
The operating costs for demineralizations are made up of the
costs of: (1) Resin; (2) chemicals; (3) Labor and Maintenance.
282
-------
soo rot» sooo
CAPACITY I CU M/DAY TREATED)
10000 ioo,oco ijooopoo
CAPACITY (GPD TREATED)
FIGURE 70
INSTALLED CAPITAL COST vs. CAPACITY
FOR DEMINERALIZATION
500 1000 IEOO JoCO 2500 JCCO 3100
TOTAL DISSOLVED SOLIDS (MG/L)
FIGURE 71
CHEMICAL COSTS FOR DEMINERALIZATION
283
-------
For the higher dissolved solids levels, chemical costs are the
primary expense. These costs are shown in Figure 71. overall
costs are given in Tables 72 and 73.
Reverse osmosis Treatment costs
The costs involved with waste treatment using reverse osmosis are
given comprehensive coverage in reference (49) . The costs for
reverse osmosis treatment include capital equipment, membrane
replacement, pretreatment, power and labor plus maintenance
materials.
The capital costs for reverse osmosis installations vary with
plant size. Small units cost $1.00 to $1.50 per 3,78 I/day
(gal/day) while large units lower this cost to $0.50 or less per
3.78 I/day as shown in Figures 72 and 73. These costs do not
include either extensive pretreatment or disposal facilities.
The selection of the membrane material, either sheet or hollow
fiber, is governed by the nature of the waste to be treated and
the product water quality desired. In general, tighter (small
pcre size) membranes have lower flux rates than more open
structured ones. Therefore, to obtain low total dissolved solids
product water, the area required for treatment will be
significantly higher than for an allowable high total dissolved
solids product water. In turn, the increased membrane surface
area will increase the capital and membrane replacement costs.
This correlation is shown in Figure 71.
Membrane life is one of the major factors of operating costs.
Currently membrane life appears to be one to three years, with
the average shifted toward the one to two year interval for
replacement. This short and variable life has restricted use of
reverse osmosis in many otherwise logical applications.
Since modules constitute one-third to one-half of the capital
equipment costs, the life of the modules is critical. Unfor-
tunately, module performance and life are difficult features to
predict and control. For this reason, cost developments in this
section are based on a two year life. As application experience
increases, improved membrane life will significantly reduce
operating costs. Table 7U summarizes membrane replacement costs
fcr a membrane life of two to three years.
Various chemical pretreatments are required to prepare feedwater
fcr passage through the membrane units. Included in these
pretreatments are pH adjustment, such as acid addition to
eliminate carbonate scaling, sulfate scaling control through
addition of sodium hexairetaphosphate, and chlorination for
organics-
-------
TABLE 72 . Overall Costs for Demineralization
FIXED BED 2-STEP DEMINERALIZATION
Co
Installed Labor and
Capital Resin Chemical Maintenance
Capacity Amortization Costs Costs Costs
Treated
-------
ro
«xt
01
TABLE 73* Overall Costs for Demineralization
SPECIALTY PROCESSES — High Efficiency-Low Cost Regeneration Units
Capacity
Treated
cu m/day(GPD)
38(10,000)
379(100,000)
3785(1,000,000)
38(10,000)
37*^00,000)
3705(1,000,000)
38(10,000)
37^(100,000)
3705(1,000,000)
Capital
Amortization
C/1000 gallons
or 3785 liters
43
21.4
12.5
43
21.4
12.5
43
21.4
12.5
Resin
Costs
-------
1000 I000O
CAPACITY [CU M/DAY TREATED)
100,000 IJ300.00Q
CAPACITY IGPD TREATED)
FIGURE
INSTALLED CAPITAL COSTS FOR
REVERSE OSMOSIS EQUIPMENT
400 ipoo 4.000 to,ooo W.ODO
CAPACITY (CU M/OW TREATED)
ipooixo
CAPACITY IGPD TREATED)
FIGURE 73
COSTS FOR REVERSE OSMOSIS TREATMENT
-------
rc
a
a
fl
O ui
°E
w 5
z <
.
60
CJ
X
111
40
30
20
15
oc
ui 10
LP-HFF2SOPSI
FEED COMPOSITION (ppm)
Na 400
C. 360
Mg 100
a 120
SO, 2000
120
4
HCO-
3100
SPIRAL WOUND
300 PSI
DASHED LINES DENOTE /
MEMBRANE PERMEABILITIES. GFD/100 PSi
INDICATES STATE-OF-THE-ART MODULES
INDICATES DEPLOYMENT OF LOW PRESSURE MEMBRANES
CURRENTLY UNDER DEVELOPMENT
GESCO
10.0
I I I I I
LI
20 30 40 50 60 70 80 90 100 150 ZOO 300
PRODUCT WATER QUALITY, TDS. ppm
400 500 600
1000
FIGURE 74 TRADE-OFF BETWEEN MEMBRANE PERMEABILITY (FLUX)
AND SELECTIVITY (REJECTION AND PRODUCT WATER
QUALITY) FOR CELLULOSE ACETATE BASE MEMBRANES
(10 MGD PLANT @ 55% RECOVERY, 3100 ppm TDS FEED)
-------
TABLE 74 . Reverse Osmosis — Membrane Replacement Costs
Volume Treated
cu m/day
g/1000 gal, or 3785 1 Treated
38
95
189
379
945
1,890
3,785
18,900
37,850
10,000
25,000
50,000
100,000
250,000
500,000
1,000,000
5,000,000
10,000,000
2 Yr.
Present
45
45
45
38
38
30
30
22
15
_Life
Future
22
22
22
20
20
15
15
12
8
3_Yri
Present
30
30
30
25
25
20
20
15
10
Life
Future
15
15
15
13
13
10
10
8
5
Taken from Reference (49), p. 108. converted to
treated basis plus two (2) year life adjustment.
cu m/day and GPD
TABLE 75*. Reverse Osmosis — Operating Costs
Volume Treated
cu_m/day GPD
0/1000 gal, or 3785 1 Treated
s Total
Cost
38
30
25
20
17
15
14
12
11.5
*At 10 per kwhr.
**Will vary depending on pretreatment required.
***Additional breakdowns in reference cited above.
38
95
189
379
945
1,890
3,785
18,900
37,850
10,000
25,000
50,000
100,000
250,000
500,000
1,000,000
5,000,000
10,000,000
6
6
6
6
6
6
6
6
6
Power*
6
6
6
6
6
6
6
6
6
Chemicals**
4
4
4
4
4
4
4
4
4
Labor P:
fUTa *? n-^AY^^ 4
Kaintena:
Materia
28
20
15
10
7
5
4
2
15
289
-------
A low energy requirement is one of the major advantages of the
reverse osmosis process. The primary energy requirement is for
high pressure pumps.
The operating costs are summarized in Table 75. Figure 73
combines the information developed into overall reverse osmosis
treatment costs. These values are based on conservative
engineering and industrial calculations and assumptions, assuming
straight line ten year depreciation, six percent money and
membrane life of two years,
Evaporation Costs
Although there are many different designs and variations of
evaporative equipment, four basic types, as described in Section
VII, are commonly employed in the inorganic chemicals
manufacturing industry. They are: (1) single-effect evaporators;
(2) multi-effect evaporators; (3) high efficiency vertical tube
and multi-effect flash evaporators; and (4) low energy specialty
evaporators. Costs for these types of equipment and their
operation are given in the following subsections.
Each type of evaporator has its individual operating
specifications, as shown in Table 76, Figure 75 compares the
energy requirements of each evaporator type with other treatment
techniques as a function of dissolved solids concentration.
The selection of evaporative equipment depends on the job re-
quirements. For high volume, low solids stream concentrations
the VTE, or multi-flash type units should be used. Ninety
percent or more of the water can be recovered as high purity
product with relatively low energy requirements. The remaining
five to ten percent can be more economically removed by recir-
culating evaporators or dryers. Although energy requirements are
high per kg of water removed for single effect evaporators and
dryers, the total energy requirement and capital costs for this
step are relatively low. High volume, high solids content
streams may be handled similarly except that conventional multi-
effect evaporators should be used for the first concentration.
Low Energy Specialty Evaporator Costs
Capital costs for a low energy specialty unit, the flat plate
vapor compression evaporator, are given below.
Capacity
cu m/day (gal/day)
379 (100,000)
850 (225,000)
1890 (500,000)
Installed Capital
Costs, $
635,000
1,350,000
2,500,000
290
-------
TABLE 76 . Evaporator Characteristics
Character-
istics
Re-
circulative
Evaporator
Multi-
^effect
High
Efficiency
Vertical
Tube
Evaporator
Low
Energy
Specialty
Evaporator
Effects
Evaporative
energy,
kg caj/kg
(Btu/lb)
Optimun
concentration
range, % by
weight of
solids
1-3
222-555
(400-1000)
20 to max.
2-6
100-333
(180-600)
10-50
10-20
42-56
(75-100)
1-10
15-30
(35-100)
1-10
Ability to
handle heavy
crystallizing
or suspended
solids food
Optimum
capacity
range
General
costs
Excel 1 ent
Best, for
small capa-
city below
5000 GPD
Relatively
low
Good,
can be
easi ly
equipped
for re-
circulation
Good ..over
wide capa-
city range
10,000-
2,000,000
GPD
Inter-
mediate
Poor,
not
operable
Mainly for
high capa-
city more
than
1 ,000,000
GPD
High
Good,
for calcium
sulfate and
other slurries
Mainly for
high capa-
city more
than
100,000
GPD
Highest
291
-------
Z6Z
ENERGY REQUIRED (BTU/lb feed)
O
c
70
m
70
O
n
O
l/l
O
O
50
CO
CO
O
O
3>
CO
CO
o
CO
o
CO
t/1
o S
o f
CO
70
m
O
-------
Larger capacities are made up of multiple small units. Operating
expenses include costs for electric power, pretreatment
chemicals, and labor.
Unlike most evaporators, this unit uses an electrically driven
compressor instead of steam for its energy. Therefore, operating
cost is directly influenced by the electrical power costs in the
area. This cost may range from $0.003/kwhr to over $0.01/kwhr.
For industrial applications, operating power costs are taken as
$0.01/kwhr. The amount of power required depends on the specific
operating conditions. The following table gives estimated power
as a function of the concentration of total dissolved solids in
the concentrate.
Concentrate TDS* (mg/1)
10,000
50,000
100,000
200,000
kwhr/1,000 gal
or 3785 1 Treated
60
65
100
250
*Tctal solids, including those suspended in the slurry,
may be several times greater than the dissolved solids.
Operating and overall costs in 0/3785 liters (1000 gallons) for
an 850 cu m/day (225,000 gpd) unit are given below:
concentrate
TCS*, mg/1
10,000
50,000
100,000
200,000
Operation
Power and
0/3785 1 (0/1QQQ gal) Chemicals Maintenance Total
0/3785 X (0/1QOQ gal)
60
65
100
250
52
52
52
52
115
120
155
305
*Since sparingly soluble water contaminants such as calcium
sulfate and silica precipitate with concentration, total
solids are usually much higher.
concentrate
TpS_rng/l
10,000
50,000
100,000
200,000
Capital
0/1,000 gal
or 3785 1_
257
257
257
257
Operation
0/1,000 gal
or 3785 1
115
120
155
305
Total
0/1,000 gal
or 3785 1
327
377
412
562
293
-------
These overall cost values are consistent with the basis used for
other calculations of this report — industrial 10 year
depreciations and higher cost electric power than would be
available to many current users. Low cost power and 35 year
capital writeoffs would bring the overall costs down to
approximately $2.00/1,000 gallons or 3785 1 treated.
It should also be emphasized that the power requirement corre-
lation with total dissolved solids neglects the suspended solids
portion of the recirculated slurry. Since many dissolved solids
such as calcium suXfate are only sparingly soluble in water,
concentration causes them to precipitate and form slurries. The
unit is designed to handle such slurries up to total solids
contents of 35 to 50 percent (at which point the total dissolved
solids might be one percent or 10,000 mg/1). The critical
difference here is that dissolved solids raise the boiling point
of the solution, whereas suspended solids do not. The ability to
handle slurries is one of the key technology advantages over
multi-flash and vertical tube evaporators which are discussed
next.
Vertical tube, multi-stage flash, and other high efficiency
evaporators have teen used in units to recover pure water from
salt or brackish sources. installed capital costs are shown in
Figure 76 and operating and overall costs are given in Figure 77.
Conventional Multi-Effect Evaporators
For the heavy-duty, very high solids evaporations, industrial
type multi-effect evaporators are commonly used. The inorganic
salts in sea water and inorganic chemical industry are very
corrosive. Even cupro-nickel and stainless steel alloys may not
be sufficient for many of the solutions involved. Therefore, for
this section, costs are given for solid nickel, titanium and
tantalum materials, as well as stainless steel. Nickel
construction raises the cost significantly, but will provide the
reliable service required for industrial applications.
In selecting the optimum number of effects, a balance has to be
made between equipment costs and operating costs. If the
addition of an effect will not pay for itself in lower steam
costs within approximately three years, the effect will probably
not be added. It is rare that more than six or seven effects can
be justified in this manner, (This is particularly true because
of the high dissolved solid solutions or waste involved).
Figures 78 and 79 show the interrelationships between number of
effects and capital cost and steam usage, respectively.
Capital ccsts may be calculated rather quickly and directly from
Figure 80:
294
-------
aooo 10.000
PLANT SIZE (CU W/QftY TREATED)
tpoofloo
PLANT SIZE I6PD TREATED)
FIGURE 7V5
INSTALLED CAPITAL COSTS vs. CAPACITY FOR HIGH
EFFICIENCY VTE OR MULTI-STAGE FIASH EVAPORATORS
CAPACITY (CU M/DAY)
CAPACITY (GPD)
FIGURE 77
OVERALL AND TOTAL OPERATING COSTS
FOR VTE AND MULT!-FLASH EVAPORATORS
295
-------
Number of Effects
EVAPORATION
Figure 7&. Capital Costs Vs. Effects
for Conventional Multi-
Effect Evaporators.
-------
200,000
400,000 */hr
EVAPORATION
IOOO
Figure 79. Steam Usage Vs. Effects for Conventional fiilti-Effect Evaporators
-------
IJXJO K1000
TOTAL HEATIM3 SURFBCE (SO M)
10,000 IOQDOO
TOTAL HEATING SURFACE (SQ FT)
FIGURE 80
CORRELATIONS OF EQUIPMENT COST WITH
EVAPORATOR HEATING SURFACE
400 SCO
1OOO SOW WOO *OOO
CftMCTTY IOJ M/CAY TREATED)
CAfWdTY I6PO TREATED)
FIGURE SI
OVERALL COSTS FOR 6-EFFECT EVAPORATOR
TREATMENT OF WASTE WATER
298
-------
Volume
Treated Total installed
cu m/dav (gal/day) Capital Cost, $
378 (100,000) 667,000
945 (250,000) 1,530,000
1890 (500,000) 2,800,000
3785 (1,000,000) 5,470,000
Analogous values for stainless steel and other construction
material capital costs may be similarly derived.
Operating costs include steam costs and labor and maintenance.
Chemical pretreatment costs are usually minimal. Operating costs
are summarized below for six-effect evaporators.
Overall costs for all-nickel and stainless steel six-effect evap-
orators are given in Figure 81.
Steam Labor and
Volume Volume Costs in Maintenance Total Costs
Treated Treated 0/3785 1 0/3785 1 0/3785 1
cu m/dav cral/dav (0/1000 gal) 10/1000 gal) (0/1000 gal)
378 100,000 95 91 186
945 250,000 95 80 175
1890 500,000 95 71 166
3785 1,000,000 95 68 163
Single-Effect Evaporators
When evaporation loads are small as for final concentrations or
minor waste streams, evaporative energy costs are secondary, in
these cases, equipment costs and reliability of operation are the
controlling considerations. Various designs are available for
handling crystallizing solids or slurries and design and
industrial technology is widely available.
Using Figure 80 and following the same procedures and costs for
energy, installation, maintenance and labor as for multieffect
evaporators, costs can be developed. Essentially, costs for
single-effect evaporators are treated as an extrapolation of the
multi-effect cost values. A summary of the costs involved is
shown below for single-effect evaporators assuming stainless
steel construction.
Capital Operating overall
Writ eof f Costs Cost s
Installed 0/3785 1 0/3785 1 0/3785 1
Treated Treated Capital
cu m/dav gal/day Costs^S 10/1000_gal) (0/1QQQ gal) (0/10QQ_gal)
38 10,000 8,000 34 564 598
299
-------
189 50,000 28,000 24
379 100,000 a5,000 19
945 250,000 80,000 14
1890 500,000 146,000 12
3785 1,000,000 267,000 11
Easis:
cu in/day
38
189
379
945
1890
3785
Treated
gal/day
10,000
50,000
100,000
250,000
500,000
1,000,000
Installation Costs
Percent of
equipment capital
100
100
50
33
33
33
551 575
545 564
539 553
536 548
533 544
Labor Costs
0/3785 1 fg/1000 gall
30
20
17
10
8
5
15 percent Capital writeoff/yr.
4 percent Capital cost/yr for maintenance materials.
90 percent Evaporation.
Steam cost — $0.70/1000 Ibs or $0.70/454 kg.
Similar values for all nickel, titanium or tantalum construction are:
Total
Capital Operating Overall
Writeoff costs Costs
Treated Treated Installed 0/3785 1 0/3785 1 0/3785 1
Volume Volume capital
cu m/day gal/day CostsA$ (0/1000 gal) (0/1000 gal) (0/1000 gal)
38
189
378
945
1890
3785
10,000
50,000
100,000
250,000
500,000
1,000,000
16,000
68,000
133,000
300,000
532,000
1,060,000
69
58
57
52
46
45
574
561
555
549
545
542
643
619
612
601
591
587
Basis: Same as previously shown except 33 percent of capital
costs are used for installation estimates for all capacities.
These figures show that single-effect evaporation costs are
largely for steam, with capital costs being only a small fraction
of the overall cost. All nickel, titanium, tantalum or other
high cost materials of construction are often needed and can be
economically used.
The high overall costs per liter treated also indicate that
single-stage evaporators are restricted to small capacities. For
example, at the 3785 cm/day (1,000,000 gal/day) capacity, yearly
overall cost for stainless steel equipment is $1,910,000.
Comparable multi-effect and VTE costs are $583,000 to $1,400,000
yearly. Obviously the higher efficiency units would be used
300
-------
whenever possible. At the 379 cu m/day (100rOOO gal/day) level,
comparable costs are $198,000/yr for single-effect, $72,200/yr
for six-effect, and $78,500/yr for 14-effect. For this case,
there is still approximately $120,000/yr savings in going to
multi-effect evaporators. Single-effect evaporators would
normally be used in the capacity range of 48 cu m/day (10,000
gal/day).
Mechanical Drying Costs
The crystallized, suspended or dissolved solids removed in the
previous evaporation section can either be recycled, sold, or
disposed of in their concentrated form. In some cases, they may
require further treatment. Whenever possible, suspended solids
should be dewatered by centrifuging or filtration. These
relatively low cost treatments may be all that is needed, or
reduction to full dryness may be required. When full dryness is
required, the filter cakes, centrifuged solids, and concentrated
solids may be subjected to conventional thermal drying. Heating
may be by gas, oil, or steam. Types of dryers include rotary
drum dryers, screw type mechanical dryers, scraped surface tunnel
dryers and heated evaporation pans.
Capital costs and labor costs are minimal in comparison to energy
costs. Labor and materials are estimated to cost $0.11 to
$0,33/kkg ($0.10 to $0.30/ton) of product for small dryers
(Reference (71). .
Taking energy costs as $0.50 per 252,000 kg cal (million BTU)
(gas or oil combustion) and an energy utilization efficiency of
50 percent, drying costs are $1.00/454 kg (1000 Ib) of water
evaporated.
Drying costs as a function of solids content are given below:
Drying Costs, Drying Costs,
Percent Solids in Feed £/454 kg 0/3758 1
by weight (1/10,000 Ib) (iZ/1000 gal)
90 10 Dry Basis
80 , 20 Dry Basis
70 30 Dry Basis
60 40 Dry Basis
50 50 420
40 60 500
30 70 580
20 80 600
Aside from the energy costs involved, there are practical drying
problems with common dissolved salts such as calcium chloride,
potassium chloride, and magnesium chloride. These can be dried
but they hold tenaciously to residual water and must be given
301
-------
special handling techniques including the use of drum flakers or
pan evaporators.
Deep Welling Costs
The capital costs for injection wells vary greatly, from $40,000
to more than $1,000,000. The costs depend on factors such as
well depth, geology, well hole size, care in drilling, well con-
struction, geographical location, pretreatment requirements,
instrumentation and monitoring, corrosion problems, injection
pressure, and maintenance. The operating life of such wells is
difficult to predict and may be very short due to blockage,
contamination of water aquifiers, or other reasons.
The principal cost factors in well construction are drilling
contractor costs and casing and tubing costs. These two factors
comprise approximately two-thirds of the total construction
costs. The larger and deeper the hole, the higher the contractor
costs will be.
Surface equipment such as pumps, filters, tank, piping, and
instrumentation can vary from 50 percent of construction costs to
100 percent or more. Injection pressures above 27 atmospheres
(400 psi) require more expensive pumps. Corrosive liquids
require more expensive materials in the liquid handling
equipment.
The average deep well capital and operating costs determined from
a recent comprehensive survey (Reference (77) are: capital cost
— $305,000; operating costs — 30i«/3785 1 (1000 gal).
Operating costs for deep well disposal range from 40/3785 1 (1000
gal) to $2.20/3785 1 (1000 gal). The lower costs are for shallow
wells, low injection pressures, minimum pretreatment, relatively
lew corrosiveness, and a minimum of monitoring and
instrumentation. The higher operating costs involve deep wells
with high injection pressures, extensive pretreatment, high
maintenance costs, extensive monitoring and instrumentation, and
corrosion resistant equipment. In any cost calculations
involving deep wells, as discussed in Section VII, either a
backup well or alternate disposal facility is necessary. This
will increase the average capital cost to approximately $500,000
(for a single-well operation).
Calculating overall costs for deep well disposal at a 1890 cu
m/day (500,000 gal/day) rate and using a 15 percent capital
amortization yields an overall cost of 732/3785 1 (1000 gal).
Solids Wastes Disposal costs
The slurries, water soluble solids and water insoluble solids
obtained from control and treatment of inorganic chemicals in-
302
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dustry water-borne wastes have to be contained, or disposed of,
in a safe and economical manner.
Provided that the solids are insoluble in water, most solid
wastes from the inorganic chemicals industry may be land dumped
or land-filled. costs are $0.22 to $0.66/kkg ($0.20 to
$0.60/ton) of solids — for simple dumping or landfilling.
Figure 82 gives a breakdown of complete landfilling costs. Large
scale operations without cover cost less than $1.11/kkg
($1.00/ton). If cover is involved for appearance or zoning
requirements, the costs may increase to $1.05 to $2.20/kkg ($1.50
to $2.00/ton).
If the evaporation-rainfall situation for the disposal area is
favorable (as is the case for much of the southwestern U.S. and
seme other areas of the country), then landfill in an impervious,
lined pan is feasible for soluble solids, operation costs are
similar to those for landfill with no cover, $0.22 to $0.66/kkg
($0.20 to $0.60/ton).
Landfilling of containerized soluble solids in plastic drums or
sealed envelopes is practicable but expensive. Blow-'molded
plastic drums, made from scrap plastic (which is one of the
present major problems in solid waste disposal) could be produced
for $ll-22/kkg ($10-20/ton) capacity at 227 kg (500 Ib) solids
per drum and a rough estimate of $2.50-5.00 cost/drum. A more
economical method, particularly for large volumes, would be
sealed plastic envelopes, 750 microns (30 mils) thick.
At $1.10/kg ($,50/lb) of film, low density polyethylene costs
atout 100 per 0.0929 sq m (1 sq ft). Using the film as trench
liner in a 1.8 m (6 ft) deep trench 1.8 m (6/ft) wide, the
perimeter (allowing for overlap) would be approximately 7.5
meters (25 feet). At a density of 1.6 gm/cc (100 Ib/cu ft) for
the solid, costs of plastic sheet/kkg would be $2.00 ($1.75/ton).
With sealing, the plastic envelope cost would be approximately
$2.20/kkg ($2/ton). With landfill costs of $2.20/kkg ($2/ton)
additional, the total landfill disposal costs would be about
$4.40/kkg ($4/ton).
The above figures for soluble disposal using plastic containers,
bags or envelopes are only rough estimates. Also, the technology
would not be suitable for harmful solids or in situations where
leaching contamination is critical.
Treatment Costs for Ancillary Water-Borne Wastes
In many plants of this study ancillary wastes such as boiler
blowdowns, cooling tower blowdowns, ion exchange regenerants, and
contributions from air purification equipment, are either the
sole or dominant contributors to water-borne wastes coming from
the plant. Rarely is removing these wastes from plant effluent
303
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Source: Rc-f. 7i
Total cost per ton
cover material purchased
at$1.5Q/cu.yd.
I 1 1
— Total cost per ton
cover material on site
1 I
-Cover material purchased
at$1.50/cu.yd.
Landfill equipment
Landfill labor
Cover material on site
300 600 900
Solid wastes, ton/wk. (six-day operation)
= kkg/weelO
1,200
Figure B2. Disposal Costs for Sanitary-handfills
304
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water considered part of the treatment of waste abatement process
costs.
Air-Borne Waste Abatement Costs
Five chemicals of this study have been selected for specific cost
analysis. They are described below.
Sulfuric Acid
Reduction of sulfur dioxide in the stack gas of sulfuric acid
plants to specified limits is expensive for most existing plants.
In each of two plants of this study (113 and 023), over
$2,500,000 has been spent for this purpose alone. As regulations
tighten, other plants will have to be modified similarly. The
nature of these modifications should be determined by the overall
costs and performance of the sulfur dioxide unit considered.
If a sulfuric acid producer does not choose to follow the path of
scrubbing sulfur dioxide from the stack gases, it will
undoubtedly be more profitable to recycle sulfur dioxide which
should have a recovered sales value of approximately $50/kkg
($45/ton) and eliminate the expense of sodium hydroxide or other
chemicals.
Both add-on double adsorption systems and other processes which
have no water-borne wastes exist. New plants all use the double
adsorption processes.
Calcium Oxide and Calcium Hydroxide
The manufacturing process for calcium oxide and calcium hydroxide
has no waste water. The only contribution is from stack
scrubbers which collect the lime dust in water.
Current practice is to settle out solids from the scrubber water
in ponds and possibly neutralize this effluent before discharge
to surface water. Plant 057 currently follows this general type
of procedure and plans to install a cyclone recovery and
calcining unit on the waste stream at a cost of $750,000. Cost
of installation will be covered by product value obtained. This
will remove almost 100 percent of the suspended solids. Some
dissolved solids remain. Calcium oxide is soluble to the extent
of about 1000 mg/1. a?he water may be recycled for closed loop
scrubbing.
A second approach, which escapes water-borne waste and waste
recovery problems, is dry bag collection. The exemplary plant of
this study has no water effluent and uses dry bag collection
systems. Installation cost was $675,000 with annual operating
costs of $37,500.
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Calcium Carbide
There is no water-borne process waste from the calcium carbide
manufacturing process. The only contributions are ancillary
wastes — cooling tower blowdowns, ion exchange regenerants and
gas stream scrubfcings.
For water scrubbers, the water effluent may be isolated,
suspended solids removed by ponding or chemical treatment,
alkalinity neutralized and a closed loop recycle instituted to
avoid dissolved solids discharge. Capital costs for a large
plant adjusted to 1973 prices are approximately $750,000 for the
scrubber system, $112,000 for improvements, plus a thickener and
settling ponds that will bring the total cost up to $1*000,000.
Recycle is possible but would require equipment modification.
Therefore, over $1,000,000 investment is needed to water-scrub
without waterborne waste with both capital and operating costs
being losses.
In contrast, one plant of this study uses dry bag collection
techniques throughout. Collection and reuse of 10 percent of the
raw materials from these dust collectors makes installation
profitable, and there are no water-borne wastes involved.
Chlorine
In contrast to the dusts from the first three processes
discussed, chlorine is a reactive and noxious gas. It is soluble
in water and forms hypochlorites with water or basic materials
present such as sodium hydroxide or calcium hydroxide.
The hypochlorites are bleaches and may be sold. They are also
reactive and can be used in the treatment of other chemical
wastes such as cyanides. This is done in plant 096. Sodium
hypochlorite may also be catalytically decomposed and reused.
Discharge must be avoided to attain the effluent reduction
possible through the application of the best available technology
economically achievable. Removal later from the waste stream
will be expensive.
Another method for direct utilization of tail gas chlorine is
direct burning with hydrogen to produce hydrochloric acid. Plant
057 is planning this approach at an estimated capital investment
of $430,000. Return on investment looks good from the standpoint
of product value and decreased sodium hydroxide usage.
Aluminum Chloride
The aluminum chloride process has no water-borne wastes, but
condenser gas scrubbing removes residual chlorine gas and en-
trained aluminum chloride fumes. Two exemplary plants (152 and
125) of this study avoid any water-borne wastes as discussed in
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Section VII. Costs for a generalized treatment process are shown
below to illustrate the dollar values involved. For a discharge
of 4.5 kg (10 pounds) of aluminum chloride and 2.25 kg (5 Ib) of
chlorine per 0.907 kkg (ton) of product in a 18 kkg/day (20
ton/day) plant, treatment costs are developed below for
neutralization with sodium hydroxide. Sodium hydroxide costs are
estimated to be $70,000/yr. Also, 195 kg/day (430 Ib) of sodium
chloride and 53 kg/day (117 Ib) of aluminum hydroxide are formed.
The volume of neutralized solution is approximately 9461/ day
(250 gal/day). Installed cost for a 379/1 (1000 gal)
neutralizing, settling and hypochlorite decomposition system plus
a small recirculating single-effect concentrator and
crystallization system would be approximately $25,000. Operating
costs including steam, electricity, disposal of solid wastes,
labor and maintenance, and chemical costs would be approximately
$12,000/yr. Overall costs of capital writeoff plus operating
costs would be approximately $16,000/yr or slightly more than
$2.20/kkg ($2/ton) of product.
Boiler Slowdowns, Cooling Tower Slowdowns, and Ion-Exchange
Regenerants Treatment Systems and Their Costs
Present water treatment facilities in existing plants are usually
not designed for zero discharge of water-borne wastes, nor are
they designed for complete closed cycle operation. The
generalized water treatment facilities given in Figure 63 earlier
in this section provide three treatment techniques for removing
dissolved solids from makeup and recycle water-demineralization,
reverse osmosis and evaporation. It is assumed from the overall
treatment model given in Figure 62 (of which Figure 63 is a
detailed portion) that suspended solids and toxic materials have
already been removed. Figure 83 gives the dissolved solids
concentration range over which each type of treatment technique
is economically feasible. Costs for different flow rates and
dissolved solids contents are given in Table 77. This table
shows that if all the incoming and recycle water and blowdowns
are less than 1000 mg/1 -total dissolved solids then
demineralizations can be used economically from 1000 mg/1 to 3500
mg/1. Specialty demineralization systems are favorable, if
available. Most blowdowns are in the 750 mg/1 to 3500 mg/1
range. Fegenerants disposal adds to the overall demineralization
costs. With these costs added, the specialty demineralization
and reverse osmosis plus evaporation treatment costs are nearly
equal in the 1000 mg/1 to 3500 mg/1 range. If any of the streams
coming into the treatment area have greater than 3500 mg/1 total
dissolved solids, then reverse osmosis and/or evaporation are
usually the only treatment approaches.
A model plant example is shown in Table 78 to illustrate needed
equipment and costs for treatment.
307
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Treatment
Ion
Exchange
Conventional
Demineral-
ization
Specialty
Demineral-
izaticns
Reverse
Osmosis
Single
Effect
Evaporator
Multi-
Effect
Evaporator
Solar
Evaporation
Chemical
Precipitation
Small Waste Streams
^379 cu m/day «100,000 GPD)
j Less than 1000 mg/1
I Up to 1000 mg/1
1 Up to 4000 mg/1
| 500 to 10,000 mg/1
X?>W%V%6 1Q*000 m?/l to Max Cone. r//V//
Y/y//// 100° ro^/1 to 100,000 mcr/l
W/y/y// 1000 mcr/l to Max Conn. 'dy////^
's^fr i Percent Total Dissolved Solids
Large Waste Streams
>379 cu m/day (> 100 ,000 GPD)
| Less than 1000 mg/1
\ Up to 1000 mg/1
2 Up to 4000 mg/1
|j 500 to 10,000 mg/1
Not Econ
Effect E
'ffifflfc
W/////A
omical - Initial By Multi-
vaporators
1000 mg/1 to 100,000 mg/1
/// 1000 mp/1 to Max Cnnn.
w////.
| 1 Percent Total Dissolved Solids
0 10 20 30 40 50 0 10
20 30 40 50
o
00
Percent Total Dissolved
Solids
Percent Total Dissolved
Solids
Figure S3, Treatment Applicability to Dissolved Solids Range in Waste Streams.
-------
TABLE 77 Cost Estimates for Different Treatment
Reverse Osmosis
Flow DemineraMzation + Evaporation
OUfl/d (GPD) Costs, $/day Costs, $/day
38(10,000)
379000,000)
3785(1 ,000,000
3^5000,000,000)
38(10,000)
37
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TA8LE 78, Model Treatment Plant Calculations
Design and Cost Basis
Waste
Category
Process Water
Cooling Tower Blowdown
Boiler Slowdowns
Air Pollution Control
Makeup Water
Equipment
Needed
Demineralizer
Reverse Osmosis Unit
Multi-Effect Evaporator
2-Sing!e-Effect Evaporators
Rotary DrumFilter
Centrifuge
Waste Treated
Process Water
Cooling Tower Blowdown
Boiler Blowdown
Make-Up Water
Air Pollution Control
Net Cost
cu m/d (GPD)
189(50,000)
cu m/d (GPD)
379(100,000)
379(100,000)
94(25,000)
38(10,000)
Total
Dissolved
Solids, mg/l
10,000
1,000
500
10,000 (Recoverable at $33/kkg
or$30/ton.t
300
Capital
Cost, $
60,000
80,000
60,000
32,000
25,000
25,000 Total $282,000
Overall Costs/Day
$ 142
$ 45
$ 45
$ 45
($ 100 credit)
$ 85 or $30,OQO/yr.
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In addition to the cost of treating the. waste streams,, approx-
imately 36-45 kkg (40-50 ton) per day of solids must be disposed
of. Disposal costs for these could range from $1.10 to $11.00
/kkg ($1 to $lO/ton). A centralized treatment system as
described gives not only zero water-borne waste but also supplies
all the demineralized water needed for boilers, operation of
cooling water towers at 95 to 98 percent recycle, and reduces
process water wastes. Since the treatment equipment is all
highly automated, labor costs are also low.
Geographic Influences on Treatment and Control Costs
Treatment and control practices and costs for the inorganic
chemicals industry depend largely on plant location.
Ocean dumping may be economically feasible only for plants with
easy access to the ocean. Even a difference of being located
directly on ocean shores as contrasted to being 80 to 160 km (50
to 100 miles) up a bay or river can change barging costs by a
factor of two. Ocean barging for titanium dioxide wastes may be
as little as $5.50 /kkg ($5/ton) of product for well-suited
plants. Costs may rise to $22-$U4/kkg ($20 to $40 /ton) for
others requiring more capital expenditures and longer barging
distances.
Deep-well disposal may be geologically feasible in some parts of
the United States but not in others. Brine well salt producers
have traditionally deep-welled their wastes. Any other disposal
method would rai se the di sposa1 cost s signif icantly. An
economically feasible method for disposal of wastes from the
Solvay soda ash plants is deep-welling. However, deep-welling
must be in accordance with local. State and Federal regulations.
Treatment and disposal situations and costs for eastern and
western United States differ widely, water is scarce in most of
the west and, therefore, is worth more for recovery and reuse.
Pure water may be worth 5.32 to 13.22/cu m (202 to 502/1000 gal).
Another difference between eastern and western U.S. is that the
West generally has less rainfall. Except for some coastal and
isolated areas, western United States has a positive evaporation-
rainfall differential. This positive differential makes it
possible to dispose of water-borne wastes by solar evaporation.
Disposal costs as low as 7.92/cu m (302/1000 gal) were given
earlier in this section. Comparable deep welling costs are
19.32/cu m (732/1000 gal).
The location, character, and size of the company-owned land
around the plant is becoming increasingly important. Many of the
older plants in the inorganic chemical industry are built on
small plcts, surrounded by industrial and residential neighbors.
Industries such as hydrofluoric acid, titanium dioxide and sodium
311
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dichromate have heavy solid waste loads but often limited storage
capacity. Even where wastes can be successfully disposed of
outside the premises, costs are higher than for plant site
storage.
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SECTION IX
EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION
OF THE BEST PRACTICABLE CONTROL TECHNOLOGY
CURRENTLY AVAILABLE
The effluent limitations which must be achieved by July 1, 1977
are based on the degree of effluent reduction attainable through
the application of the best practicable control technology cur-
rently available. For the inorganic chemical industry, this
level of technology was based on the best existing performance by
exemplary plants of various sizes, ages and chemical processes
within each of the industry's product subcategories.
Best practicable control technology currently available empha-
sizes treatment facilities at the end of a manufacturing process
but also includes the control technology within the process
itself when it is considered to be normal practice within an
industry. Examples of waste management techniques which were
considered normal practice within the inorganic chemicals
industry are:
a. manufacturing process controls
b. recycle and alternative uses of water
c. recovery and/or reuse of waste water constituents.
Consideration was also given to:
a. The total cost of application of technology in relation to
the effluent reduction benefits to be achieved from such
application;
b. The size and age of equipment and facilities involved;
c. The process employed;
d. The engineering aspects of the application of various
types of control techniques;
e. Process changes;
f. Non-water quality environmental impact (including energy
requirements).
The following is a discussion of the best practicable treatment
methods currently available for each of the chemical
sutcategories, and the effluent limitations on the significant
pollutant parameters in their effluents.
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EFFLUENT REDUCTION ATTAINABLE USING BEST PRACTICABLE TECHNOLOGY CURRENTLY
AVAILABLE
Based upon the information contained in Sections III through VIII
of this report, the following determinations were made on the
degree of effluent reduction attainable by the application of the
best practicable control technology currently available in the
various subcategories of the inorganic chemicals industry.
General Water Guidelines
Process water is defined as any water directly contacting the
reactants, intermediates, waste products, or end-products of a
manufacturing process including contact cooling water. Not
included in the guidelines are noncontact cooling water or
ancillary waste streams resulting from steam and water supply.
All values of guidelines and limitations presented belcw are
expressed as kg of pollutant/kkg of product (Ib/ton). While
concentrations and flow are cited as the basis on which the
guidelines were developed, the effluent limitations describe the
allowable quantities of pollutants which may be discharged per
unit of production. No limitations are established for either
pollutant concentration or process waste water flow. The daily
maximum limitation is double the thirty day average. Extensive,
long-term data is not"availableforeach ofthe 22 chemical
sutcategories. It was necessary, therefore, to rely on data from
other segments of the inorganic chemicals industry, as well as
data from other industrial categories. Based on this information
and using good engineering judgement on the performance
reliability of recommended treatment systems, a factor of two
appears reasonable.
Aluminum Chloride
The process used for the manufacture of anhydrous aluminum
chloride uses no water except in cases where a scrubber is
employed to eliminate or reduce the discharge of unreacted
chlorine gas. There are essentially three different grades of
anhydrous aluminum chloride product made using the process of
reacting chlorine gas with molten aluminum. The grey product is
aluminum-rich, the white product is made from stoichiometric
quantities of aluminum and chlorine, and the yellow product is
chlorine-rich. The grey and white product manufacture releases
little or no chlorine from the reactor and, therefore, dry
collection methods can be employed to minimize air pollution.
The manufacture of yellow product requires wet scrubbing to trap
the excess chlorine gas.
An exemplary aluminum chloride plant uses a wet scrubber to
produce a 28 percent aluminum chloride solution as a product for
sale and has no water discharge. In cases where wet scrubbing is
required and a favorable market for aluminum chloride solutions
314
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dees not exist, the scrubber effluent may be treated to
precipitate the aluminum salts from solution. The supernatant
may then be recycled to the scrubber. Since the volume of water
discharged from the scrubber system in plant 125 is only 2720
I/day (720 gal/day), another treatment approach consists of
concentrating the scrubbing water with respect to aluminum
chloride by recycling and then evaporating to dryness to recover
additional product.
The effluent limitations guidelines for aluminum chloride plants
based on best practicable technology currently available require
no discharge of process waste water pollutants to navigable
waters.
Aluminum Sulfate
Aluminum sulfate is made by digesting bauxite ore or aluminum
clays in sulfuric acid. The wastes emanating from this process
consist of insolubles such as iron and silicon oxides- These
wastes are removed during settling and filtration of the product
alum solution and also during washdown of tanks. In two
exemplary plants (049 and 063) , the waste muds are ponded to
settle the solids and the clear water is recycled to the process.
No process waste water pollutants are discharged. Costs for the
entire aluminum sulfate industry to achieve this level of
pollution control average $0.90/ton of product, which is
approximately 1.5 percent of the list price of aluminum sulfate.
While it is recognized that the raw waste load generated by the
manufacture of aluminum sulfate increases when aluminum clays or
other impure raw materials are used as the source of aluminum,
the production process is the same as for bauxite ore.
Therefore, the use Of raw materials other than bauxite ore does
net preclude adoption of the best practicable technology
currently available. One plant using clay as its raw material is
able to totally recycle its process water.
Because of the negative water balance associated with aluminum
sulfate production, the pond supernatant may be totally recycled
with no discharge of process waste water pollutants. Muds and
other impurities settle out and allow the supernatant to be
reused without a build-up of contaminants. A discharge allowance
is provided to permit the discharge of rainwater in excess of
evaporation. This water must be treated to a 25 mg/1 suspended
solids concentration on the average and be within the pH range of
6.0 to 9.0. An untreated discharge is allowed in the event of a
catastrophic rainfall in excess of the maximum 24-hourF 10-year
rainfall event.
The effluent limitations guidelines for aluminum sulfate plants
based on best practicable technology currently available require
315
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no discharge of process waste water pollutants to navigable
waters.
No discharge of process waste water pollutants to navigable
waters is also the effluent limitaion for plants producing iron-
free alum. The production of iron-free alum requires pure raw
metals, that is, iron-free sulfuric acid and iron-free hydrated
alumina. The refining of the bauxite to produce the ircn-free
hydrated alumina yields wastes that must be segregated from the
alum production process waters. The refining of bauxite to
alumina is included in the nonferrous metal manufacturing point
source category. Effluent guidelines for this refining process
are presented therein.
Calcium Carbide
The data cited from plant 190 using an open furnace shows that
the only manufacturing wastes involved are dusts emerging in tail
gases from the furnaces. These are collected by dry bag fil-
tration methods and are reused in the process or disposed of as
solid wastes by landfilling. Dry bag collection of solid waste
constitutes the best practicable control technology currently
available. Because the segment of the calcium carbide industry
covered herein is currently using this technology, no additional
costs are required for treatment. Because plants manufacturing
calcium carbide in covered furnaces typically recover the waste
carbon monoxide, dry bag collection may be not universally
applicable. Wet scrubbers are typically used to remove
impurities from this gaseous stream. Hence, plants using covered
furnaces are considered separately and wil be included in a
forthcoming study.
The effluent limitations guidelines for calcium carbide plants
using open furnaces based on best practicable technology
currently available require no discharge of process waste water
pcllutants to navigable waters.
Calcium Chloride
Calcium chloride is produced by extraction from natural trine and
as a by-product of soda ash manufacture by the Solvay Process-
The guidelines presented herein apply only to the brine
extraction process.
The process wastes are weak brine solutions, which emanate from
the blowdown of various brine purification steps and from several
evaporation steps used in the process. The best practicable
treatment technology is to pass the waste brine streams through
ponds to settle suspended solids and adjust pH. Final ponding is
used to remove additional suspended solids before discharge. The
process water discharge flow averages 330 1/kkg of product (79
gal/ton), and contains suspended solids but no harmful metals.
316
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The limitations are based on the performance of a well-designed
and operated settling basin which will reduce the concentration
of suspended solids to 25 mg/1. While it is recognized that
significant quantities of dissolved solids may be present in the
effluent, it was concluded that removal of these pollutants
requires advanced treatment and expense beyond the definition of
best practicable technology.
The following limitations constitute the quantity or quality of
pollutants or pollutant properties which may be discharged after
application of the best practicable control technology currently
available by calcium chloride plants using the brine extraction
process:
TSS 0.0082 kg/kkg (0.0164 Ib/ton)
pH within the range 6.0 to 9.0
Calcium Oxide and Calcium Hydroxide
The manufacture of calcium oxide by the calcination of limestone
is a dry process and uses only noncontact cooling water, and, in
some cases, scrubber water. Plant 007 uses dry bag dust
collectors and, therefore, discharges no process water. The use
of dry bag collection methods is not contingent on the use of
specific fuels for the calcination kilns nor is it geographically
dependent. In plants with wet scrubbing systems already
installed, the scrubbing solution may be reused in the process,
or used to produce a low-grade product. One lime plant using wet
scrubbers is able to completely recycle the scrubbing solution.
Solids may be removed in settling vessels or ponds. For plants
using ponds for treatment prior to reuse, a provision has been
established to allow a discharge from impoundments in areas where
rainfall exceeds evaporation. This discharge must be within the
pH range of 6.0 to 9.0 and contain, on the average, a suspended
solids concentration not to exceed 25 mg/1. In the event of a
catastrophic rainfall exceeding the maximum 10-year, 24-hour
event, an untreated discharge is allowed.
Plants using dry baghouses will not have to spend additional
money to achieve the effluent reduction attainable by the
application of best practicable technology currently available.
Plants with wet scrubbers may have to invest up to an average of
$1.28/ton of product.
The effluent limitations guidelines for calcium oxide and calcium
hydroxide plants based on best practicable technology currently
available require nc discharge of process waste water pollutants
to navigable waters.
Chlorine and Potassium or Sodium Hydroxide
(a) Diaphragm cell process
317
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The diaphragm cell process for the manufacture of chlorine and
caustic soda or caustic potash usually have the following raw
wastes emanating from the process:
a. a solution of sodium hypochlorite and sodium bicarbonate
from the scrubbing of chlorine tail gases (about 7.5 kg
of dissolved solids/kkg of chlorine produced).
b. chlorinated organics from the liquifaction of chlorine
gas (about 0.7 kg/kkg of chlorine produced)
c. brine wastes from the brine purification system {about
12.2 kg of dissolved solids /kkg of chlorine produced)
d. spent sulfuric acid from the chlorine drying process
(about 4.2 kg/kkg of chlorine produced)
e. weak caustic and brine solution from the caustic evap-
orators using barometric condensers (about 9.5 kg of
dissolved solids/kkg of chlorine produced)
f, weak caustic and brine solution from the caustic filter
washdown (about 37.5/kg of dissolved solids/ kkg of
chlorine produced).
At plant 157, the tail gas scrubber wastes are presently
discharged. However, the installation of a chlorine burning
hydrochloric acid plant will eliminate the scrubber wastes. This
addition is practicable, as substantiated by plant 157's plans
for installation in the near future. The chlorinated organics
are disposed of by incineration. The brine wastes from brine
purification are ponded to settle out suspended solids and the
brine liquor is recycled to brine make-up. The spent sulfuric
acid at this plant is utilized elsewhere in the complex or may be
sent to a spent sulfuric acid plant for regeneration. Some
plants presently use this 'acid to partially neutralize caustic
wastes in the plant which aides in controlling the effluent pH.
The weak caustic/brine solution from the caustic evaporators can
be eliminated by replacing the barometric condensers with
noncontact surface condensers or by recycling the discharge from
the barometric condenser back to brine make-up. The weak
caustic/brine solution from the caustic filters is presently pH
adjusted and discharged. Diaphragm cell chlorine plants will
need to invest approximately $0.30/ton of chlorine produced to
implement best practicable technology currently available.
Lead is sometimes present in the effluent as a result of cracks
around protective resin seals which encase underlying lead
mountings. Currently one-third of the industry is using anodes
which eliminate the lead discharge. Industry representatives
state that another one-third are seriously considering
conversion. The lead limitation is the average value discharged
from three plants which have not converted to lead-free anodes.
The suspended solids limitation is based on a well-operated
sedimentation vessel or pond designed to treat suspended solids
to a 25 mg/1 concentration.
318
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The following limitations constitute the quantity or quality of
pollutants or pollutant properties which may be discharged after
application of the best practicable control technology currently
available by diaphragm cell chlor-alkali plants:
TSS 0.32 kg/kkg (0.64 Ib/ton)
Lead 0.0025 kg/kkg (0.005 Ib/ton) of chlorine
pH within the range 6.0 to 9.0
(b) Mercury cell process
The mercury cell process for the manufacture of chlorine and
caustic soda or caustic potash usually has similar wastes to the
diaphragm cell process. The major exception is the loss of mer-
cury from the process. Exemplary plants 144, 098 and 130 have
excellent mercury control systems to minimize the incorporation
of mercury into discharge streams. These controls consist of
curbing the cell area to retain mercury lost in spills or leaks,
collecting all mercury before ponding and discharge and/or
recycling mercury-containing waste water back to the cells for
reuse after treatment to remove any impurities. These plants
have continuous mercury monitors on streams possibly contaminated
that are meant for ponding to settle suspended solids before
discharge. The mercury recommendation is twice the discharge
performance achieved by the three plants studied, whose
discharges per ton of chlorine are very similar. The mercury
limitation represents the quantity of mercury discharged from the
mercury treatment system. Residual mercury may be present in
other portions of the plant and may contribute to the total
mercury discharge. Residual mercury levels are difficult to
quantify on a production basis and are, therefore, not the
subject of the limitations presented below. Costs for the
industry to achieve best practicable technology currently
available are estimated to be $2.74/ton of chlorine produced.
The following limitations constitute the quantity or quality of
pollutants or pollutant properties which may be discharged after
application of the best practicable control technology currently
available by mercury cell chlor-alkali plants:
TSS 0.32 kg/kkg (0.65 Ib/ton) of chlorine
Mercury 0.00014 kg/kkg (0.00028 Ib/ton) of chlorine
- pH within the range 6.0 to 9.0
Hydrochloric Acid
The manufacture of hydrochloric acid by the chlorine burning
process comprises a minor part of total U.S. production. All of
the chlorine burning facilities are located within chlcr-alkali
coirplexes. Plant 121 is one such facility. The only waste
generated from this process consists of weak hydrochloric acid,
which is generated only during startup of the operation. No
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waste emanates from the process during normal operation. The
startup weak acid waste is normally neutralized with sodium
hydroxide which yields dissolved solids (sodium chloride)
amounting to about 0.5 kg/kkg (1 Ib/ton) of product acid. The
weak brine startup waste from the hydrochloric acid plant may be
utilized in the brine make-up operation at the chlor-alkali
portion of the complex, reused in acid manufacture.
Any leaks and spills must be contained and collected. If
adequately segregated from other waste streams, the spills and
leaks may be reused or sold. Good housekeeping, operation and
maintenance will minimize or eliminate leaks and spills.
The effluent limitations guidelines for chlorine-burning
hydrochloric acid plants based on best practicable technology
currently available require no discharge of process waste water
pollutants to navigable waters.
Hydrofluoric Acid
The manufacture of hydrofluoric acid by the reaction of fluospar
(about 97 percent calcium fluoride) with sulfuric acid generates
about 3.1-3.6 kkg (3.5 - 4.0 tons) of solid waste/kkg of product
acid. All wastes from the process may be water slurried to
settling ponds, and the clear liquid recycled. All process water
can be segregated from noncontact cooling water. At least one
plant in the industry uses this recycle technology to eliminate
its process waste water discharge.
All leaks and spills must be contained and may be recycled, sold
or pumped to the settling pond for treatment prior to reuse.
Good housekeeping, operation, and maintenance will minimize or
eliminate leaks and spills. A discharge is permitted from the
impoundment if rainfall exceeds evaporation, or in the event of a
catastrophic rainfall in excess of the maximum 24-hour, 10-year
event. Except from discharges as a result of a catastrophic
rainfall, the thirty-day average concentration of any effluent
must not exceed 25 mg/1 suspended solids and 15 mg/1 fluoride.
The pH must be within the range 6.0 to 9.0.
The effluent limitations guidelines for hydrofluoric acid plants
based on best practicable technology currently available require
no discharge of process waste water pollutants to navigable
waters.
Hydrogen Peroxide
(a) Organic process
The organic process for the manufacture of hydrogen peroxide at
plant 069 generates a waste stream containing 0.17-0.35 kg/kkg
(0,34-0.70 Ib/tcn) of organics. The treatment methods currently
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used at this plant include an 80 percent reduction of hydrogen
peroxide to water and oxygen, a recovery system which recovers
60-70 percent of lost organics, and tank diking and process
curbing to retain waste spills. The process water use in this
facility is 16,000 1/kkg of product (3,800 gal/ton) and contains,
after treatment, suspended solids and organic matter, but no
harmful metals. The guidelines are based on the treatment
systems used at plant 069 and the actual performance of these
operations. The cost to implement these technologies is
estimated to be $1.00/ton of product.
The following limitations constitute the quanitity or quality of
pollutants or pollutant properties which may be discharged after
application of the best practicable control technology currently
available by organic process hydrogen peroxide plants:
TSS 0.40 kg/kkg (0.80 Ib/ton)
TOG 0.22 kg/kkg (0.44 Ib/ton)
pH within the~range 6.0 to 9.0
(b) Electrolytic process
There is only one plant in the U.S. that makes hydrogen peroxide
by the electrolytic process. Plant 100 recovers all of the
solids present in the process wastes and uses an ion exchange
system to remove 98 percent of the cyanides present in the waste
stream before discharge. The ion exchange regenerant is pH
controlled prior to discharge. The effluent limitations are
based on the performance of treatment systems employed at plant
100. Suspended solids are discharged in concentrations less than
25 mg/1 and the oxidizable cyanide concentration averages 2 mg/1.
The following limitations constitute the quantity or quality of
pollutants or pollutant properties which may be discharged after
application of the best practicable control technology currently
available by electrolytic process hydrogen peroxide plants:
TSS 0.0025 kg/kkg (0.005 Ib/ton)
Cyanide 0.0002 kg/kkg (0.0004 Ib/ton)
pH within the range 6.0 to 9.0
Nitric Acid
Commercial grade nitric acid (up to 70 percent concentration) is
made by the oxidation of ammonia. At plant 114, all process
waters are recycled with no discharge of process waste water
pollutants. Of the 30,280 cu m (8 million gal) of water/day used
for cooling, about 95 percent is recycled. An additional 757 cu
m/day (0.02 mgd) are used to make steam and 75 percent of this
quantity is recycled. About 87 cu m (23,000 gal)/day of steam
condensate is used for acid make-up water. The discharge from
the plant consists of noncontact cooling water which contains
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blowdowns from boilers, cooling towers and water treatment with a
total waste load amounting to about 2 kg/kkg (U Ib/tcn) of
product produced.
The best practicable treatment technology available for
commercial grade nitric acid plants is the recycle of all process
waters and the segregation of process waters frcm cooling water
as demonstrated in plant 114. Volumes of waste water as a result
of leaks and spills may be minimized or eliminated ty good
housekeeping, operation and equipment maintenance. These waste
waters should be collected and may be recycled with the weak acid
streams from condensers or may be sold as a weak acid product.
It is estimated that $0.22/ton of product is required to
implement these technologies.
The effluent limitations guidelines for plants producing nitric
acid up to 70 percent concentration based on best practicable
technology currently available require no discharge of process
waste water pollutants to navigable waters.
Potassium Metal
Plant OU5 produces most of the potassium metal manufactured in
the U.S. by a completely dry process. No water is used.
Therefore, the effluent limitations guidelines based on best
practicable technology currently available require no discharge
of process waste water pollutants to navigable waters.
Potassium Dichromate
The process for the production of potassium dichromate involves
the reaction of potassium chloride with sodium dichromate. At
plant 002, all process water is recycled and sodium chloride (UOO
kg/kkg of product) is removed as a solid waste. The only water-
borne waste source is contamination of cooling water by
hexavalent chromium in a barometric condenser presently in use on
the product crystallizer. The plant has plans to replace the
barometric condenser with a noncontact heat exchanger which will
eliminate cooling water contamination. Best practicable
technology currently available requires total recycle of process
waste waters. The waste liquor from the salt concentrator may be
recycled to the reaction mix tank. Chromium discharges may be
eliminated by installing noncontact heat exchangers. Costs to
implement these technologies are estimated to be $4.65/ton of
product. This is approximately one percent of the list price of
potassium dichromate.
The effluent limitations guidelines for potassium dichromate
plants based on best practicable technology currently available
require no discharge of process waste water pollutants to
navigable waters.
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Potassium Sulfate
All of the potassium sulfate manufacturers in the U.S. are
located in the arid southwest near deposits of langbeinite ore
(K2S04.2MgS04). the reaction of this ore with a potassium
chloride solution and the subsequent crystallization and
separation of potassium sulfate from magnesium chloride hrine
constitutes the process for the production of potassium sulfate.
A large amount (about 2000 kg/kkg of product) of magnesium
chloride brine is a co-product of this process. Plant 118 sells
most of this brine when the sodium content of the ore is low. it
ponds the brine for evaporation when it cannot be sold.
Evaporation ponds in this area of the country are feasible. The
cost of water is a problem and most of the liquor in the brine is
recycled back to the process for reuse before the magnesium
chloride is sold or dumped. Other insoluble wastes from the
process muds amount to about 15 kg/kkg of product, and they are
landfilled. Because of the geographical dependence of plants
manufacturing potassium sulfate to the arid southwest evaporation
ponds are considered to be the best practicable technology
currently available.
The effluent limitations guidelines for potassium sulfate plants
based on best practicable technology currently available require
no discharge of process waste water pollutants to navigable
waters.
Sodium Bicarbonate
Sodium bicarbonate is manufactured by the carbonation of a sodium
carbonate solution. Most plants are located in or near complexes
manufacturing soda ash by the Solvay Process. There is one
isolated facility which uses mined soda ash as a raw material.
Plant 166 is located within a Solvay Process complex. The major
wastes from this process are about 10 kg of undissolved sodium
bicarbonate/kkg of product and an average of about 38 kg of
dissolved sodium bicarbonate/kkg of product. Some of the
undissolved sodium bicarbonate is reusable and it is redissolved
and recycled to the process. The remainder is landfilled along
with sand from the filters and other non-process solid waste.
The weak slurry thickener overflow, which constitutes their
present source of waste, may be used as a source of liquid for
the product dryer scrubber. Recycling this liquid to concentrate
it with respect to sodium carbonate will enable it to be reused
in the process. These process changes will eliminate the
discharge of process waste waters. One plant plans to
incorporate this technology into its manufacturing process.
Costs for implementation of best practicable technology currently
available are expected to be offset by recovered product values.
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The effluent limitations guidelines for sodium bicarbonate plants
based on best practicable technology currently available require
no discharge of process waste water pollutants to navigable
waters.
Sodium Carbonate
The Solvay Process for the manufacture of sodium carbonate (soda
ash) involves the reaction of sodium chloride brine, ammonia and-
carbon dioxide to yield crude soda ash. The ammonia is recovered
from the process by reacting the spent brine solution with lime
followed by distillation. This process produces about 1500 kg of
dissolved solids waste/kkg of soda ash manufactured. Calcium
chloride comprises the majority of this waste, amounting to about
1050 kg for every kkg of soda ash. Plant 166 recovers about 21
percent of the waste calcium chloride for sale. The total
recovery of calcium chloride is not practical because of the
limited market. The only treatment used at this plant is a
settling pond to reduce the concentration of suspended solids in
the effluent. Therefore the effluent limitations guidelines are
not based en by-product recovery, but upon the water flow
necessary to maintain the total calcium chloride by-product
formed in the process at a 10 percent concentration at discharge
900 1/kkg of soda ash (1,650 gal/ton)^ Suspended solids tut no
harmful metals may also be present. Large quantities of
dissolved solids, primarily chlorides, are generally present in
the effluent. Considering the available treatment technologies
to remove chlorides and their associated costs, it was concluded
that, in this case, dissolved solids removal is beyond the scope
of best practicable technology currently available.
The following limitations constitute the quantity or quality of
pollutants or pollutant properties which may be discharged after
application of the best practicable control technology currently
available by sodium carbonate plants using the Solvay Process:
TSS 0,17 kg/kkg (0.3U Ib/ton)
pH within the range 6.0 to 9.0
Sodium Metal
The process for the manufacture of sodium metal, commonly called
the Downs Cell Process, is essentially dry. However, water-borne
wastes are generated during cleanout and washdown of cells when
the electrolyte is replenished, from scrubbing chlorine tail
gases and from drying the chlorine with sulfuric acid. At plant
096, the spent drying acid is not discharged but used elsewhere
in the works complex. The wastes from cell wash-downs, runoff
water and residual chlorine-containing water from the tail gas
scrubber are ponded to settle suspended solids and then
discharged. At plants where the utilization of the spent drying
acid and calcium hypochlorite solution is not possible, the spent
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acid may te recovered or sold to a "decomp" sulfuric acid plant
and the calcium hypochlorite solution be recovered and marketed
as a bleach product. The limitations are based on the discharge
volume of process water other than barometric condensers which
contributes only small quantities of TSS. Treatment of the
process water in well-designed settling basins to a 25 mg/1
concentration is considered to be best practicable technology
currently available.
The following limitations constitute the quantity or quality of
pollutants or pollutant properties which may be discharged after
application of the best practicable control technology currently
available by sodium metal manufacture plants:
TSS 0.23 kg/kkg (O.U6 Ib/ton)
pH within the range 6.0 to 9.0
Sodium Chloride
(a) Solar evaporation process
Solar salt is produced by the long-term solar evaporation of sea
water to precipitate sodium chloride. This process generates a
bittern waste solution consisting mainly of sodium, potassium and
magnesium salts. Plant 059 reclaims some of the waste salts from
the bitterns and stores the rest for future reclamation. Because
this impoundment procedure is dependent on the availability of
large areas of land for storage ponds, it may not be generally
applicable. Until recovery of magnesium and potassium values
proves economical, unused bitterns may be returned to the . source
of the original brine solution provided that no additional
pollutants are added,
(t) Solution brine-mining process
Sodium chloride manufacture by this process involves pumping
water into an underground salt deposit (solution mining) and
returning the brine for treatment to remove impurities. Multiple
effect evaporators are used to crystallize and collect the pure
sodium chloride for sale. At plant 030, the brine sludges from
the brine purification step are disposed of by returning them to
the mine. Other sources of waste water are the purges from the
evaporators, spills and the barometric condenser. All of the
concentrated brinet wastes are recycled to the process. The
current plant effluent is neutral in pH and low in suspended
solids. Best practicable technology currently available consists
of treating the solid-containing waste streams in a well-designed
and operated settling pond.
The following limitations constitute the quantity or quality of
pollutants or pollutant properties which may be discharged after
application of the best practicable control technology currently
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available by solution mining evaporative process sodium chloride
plants:
TSS 0.15 kg/kkg (0.30 Ib/ton)
pH within the range 6.0 to 9.0
Sodium Dichromate and Sodium Sulfate
These two chemicals are manufactured as co-products ty the
calcination of a mixture of chrome ore, soda ash and lime
followed by water leaching and acidification of the soluble
chromates„ The sodium sulfate product is crystallized out after
acidification. The bulk of the waste originates from the
undigested portions of the ore and is mostly solid wastes.
Water-borne wastes arising from spills and washdowns contain most
of the hexavalent chromium. Treatment at plant 184 consists of
containment of spills, leaks and rain water runoff in chromate
areas of the plant, followed by treating the chromium-containing
waste water with pickle liquor to affect reduction of the
chromates and then lagooning to settle suspended solids before
discharge. This treatment removes 99 percent of the hexavalent
chromium. Dichromate plant 014 uses the more conventional sodium
hydrosulfide treatment to reduce the hexavalent chromium.
Subsequent lime treatment limits the discharge to the solubility
limits of calcium sulfate (2000 mg/1) and about 0.05 mg/1 of
unreacted hexavalent chromium and a total chromium level of 0.44
mg/1. The effluent limitations are based on chromium treatment
to these levels and suspended solids removal in a well-operated
settling basin, designed to reduce TSS to a 25 mg/1
concentration. Costs to achieve this treatment level are
estimated to be $16/ton of sodium dichromate which is about a.6
percent of its list price.
The following limitations constitute the quantity or quality of
pollutants or pollutant properties which may be discharged after
application ^of the best practicable control technology currently
available by sodium dichromate and sodium sulfate coproduct
plants:
TSS 0.22 kg/kkg,(0.44 Ib/ton)
Cr(+6) 0.0009 kg/kkg (0.0018 Ib/tcn)
Cr(T) 0.0044 kg/kkg (0.0088 Ib/ton)
pH within the range 6.0 to 9.0
scdium Silicate
sodium silicate is produced by the reaction of soda ash and
silica in a furnace to form a sodium silicate glass. The
material is sold either as a solid glass product or is pressure
dissolved in water and sold as a solution with various ratios of
silica to sodium oxide. The water-borne waste generated consists
of unreacted silica, sodium hydroxide and sodium silicate from
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tank washdowns, product shock cooling with water and scrubber
effluent. At plant 072, these wastes are ponded to settle the
solids and the clear liquid is partially recycled. Best
practicable technology currently available consists of
sedimentation and neutralization of the effluent. The suspended
solids settle efficiently and the waste water should contain only
dissolved sodium sulfate and virtually no sodium silicate.
The following limitations constitute the quantity or quality of
pollutants or pollutant properties which may be discharged after
application of the best practicable technology currently
available by sodium silicate plants:
TSS 0.005 kg/kkg (0.01 Ib/ton)
pH within the range 6.0 to 9.0
Sodium Sulfite
Sodium sulfite is manufactured by the reaction of sulfur dioxide
with soda ash. The process wastes are mainly sulfides from
product purification and sodium sulfite/sodiurn sulfate solutions
from the product dryer ejector, filter washings and vessel
cleanouts. Plant 168 is the only sodium sulfite plant currently
treating the waste sulfite-containing solutions to oxidize
sulfite to sulfate. The efficiency of this aeration treatment is
atcut 94 percent. This treatment reduces the COD to the level
required by best practicable technology currently available. An
additional filtration treatment is given to the process waste
water which removes 98 percent of the suspended solids. This
treatment reduces TSS to below 25 mg/1. The limitations are
based on the waste stream emanating from the dryer ejector and
filter wash operations of this plant at the high end of its range
(630 1/kkg or 150 gal/ton).
The following limitations constitute the quantity or quality of
pollutants or pollutant properties which may be discharged after
application of the best practicable control technology currently
available by sodium sulfite plants:
TSS 0.016 kg/kkg (0.032 Ib/ton)
COD 1.7 kg of dichromate ion/kkg
pH within the range 6.0 to 9.0
Sulfuric Acid
Sulfuric acid is manufactured using the sulfur-burning contact
process by three different types of plants. These are single
absorption plants, double absorption plants and spent acid
plants. The guidelines presented herein do not apply tc spent
acid plants or by-product sulfuric acid production, as in copper
smelting operations.
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Plant 141 is a single absorption plant and plant 086 is a double
absorption plant. The double absorption plant has no process
waste and uses only noncontact cooling water. The single
absorption plant requires the use of wet scrubbing to minimize
air pollution, and the scrubber water is recycled. There is no
discharge of process waste water from these plants. A sulfuric
acid plant in Finland neutralizes its scrubber water. The salt
solution is then concentrated into fertilizer feed. Leaks and
spills may be minimized or eliminated by good housekeeping,
operation and equipment maintenance. Leaks should be segregated
from other waste streams and may be reused in the process or sold
as a weak acid solution.
The effluent limitations guidelines for single and double
absorption sulfur burning sulfuric acid plants based on best
practicable technology currently available require no discharge
of process waste water pollutants to navigable waters.
Titanium Dioxide
a) Chloride process
Chloride process plant 009 uses neutralization, clarification and
ponding to settle suspended solids and to precipitate metals.
Abcut 93 percent of the cooling water is recycled but there
appears to be no practical approach for recycling process water.
Deep well disposal is utilized by another company (plant 160).
The plant effluent is neutral pH and contains mostly sodium
chloride as the dissolved solid.
Best practicable technology currently available consists of lime
treatment and sedimentation to reduce the iron concentration to U
mg/1 and the TSS to 25 mg/1. The guidelines are only applicable
to discharges resulting from titanium dioxide production. They
do not include any wastes resulting from ore beneficiation. In
some cases, all titanium tetrachloride is not used to produce
titanium dioxide. The guidelines include only those wastes which
may be attributed to titanium dioxide production.
The following limitations constitute the quantity or quality of
pollutants or pollutant properties which may be discharged after
application of the best practicable control technology currently
available by titanium dioxide plants using the chloride process:
TSS 2.2 kg/kkg (4.4 Ibs/ton)
iron 0.36 kg/kkg (0.72 Ib/ton)
pH within the range 6.0 to 9.0
b) sulfate process
The high iron content in the ilmenite ore raw material is a major
source of the wastes generated by this process. Another major
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contributor to the process waste is the large amount of spent
sulfuric acid from digestion of the ore. Very little treatment
is presently being used and The effluents from these plants are
highly acidic and contain high concentrations of suspended and
dissolved solids including metal ions. Ocean barging is used by
some to dispose of the process waste waters. Plant 122 is
presently installing treatment facilities to neutralize and
oxidize the process waste to remove acid as calcium sulfate, to
reduce the chemical oxygen demand and reduce the concentration of
harmful metal ions. Additional settling ponds are planned to
reduce the quantities of suspended solids formed during the
neutralization treatment, considerable research is being done to
improve treatment technologies for this process. Best
practicable technology currently available consists of lime
neutralization and settling. This treatment system will remove
iron and suspended solids, while coprecipitating other metal ions
such as vanadium, chromium, and manganese. The limitations are
based on a suspended solids concentration of 50 mg/1 and an iron
concentration of 4 mg/1. A flow basis of 210,000 1/kkg was used.
This flow may be achieved by recycling scrubber water to the
process.
The following limitations constitute the quantity or quality of
pollutants or pollutant properties which may be discharged after
application of the best practicable control technology currently
available by sulfate process titanium dioxide plants:
TSS 10.5 kg/kkg (21.0 Ib/ton)
Iron 0.84 kg/kkg (1.68 Ib/ton)
pH within the range 6.0 to 9-0
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SECTION X
EFFLUENT REDUCTION ATTAINABLE THROUGH THE
APPLICATION OP THE BEST AVAILABLE
TECHNOLOGY ECONOMICALLY ACHIEVABLE,
The effluent limitations which must be achieved by July 1, 1983
are based on the degree of effluent reduction attainable through
the application of the best available technology economically
achievable. For the inorganic chemical industry, this level of
technology was based on the best control and treatment technology
employed by a point source within the product subcategory, or
where it is readily transferable from one industry process to
another.
The following factors were taken into consideration in deter-
mining the best available technology economically achievable:
a. the age of equipment and facilities involved;
b. the process employed;
c. the engineering aspects of the application of various
types of control techniques;
d. process changes;
e. cost of achieving the effluent reduction resulting from
application of the best available technology economically
achievable; and
f. non-water quality environmental impact (including energy
requirements).
In contrast to the best practicable technology currently
available, best available technology economically achievable
assesses the availability in all cases of in-process controls as
well as control or additional treatment techniques employed at
the end of a production process. In-process control options
available which were considered in establishing these control and
treatment technologies include the following:
a. alternative water uses
b. water conservation
c. waste stream segregation
d. water reuse
e. cascading water uses
f. by-product recovery
g. reuse of waste water constituent
h. waste treatment
i. good housekeeping
j. preventive maintenance
k. quality control (raw material, product, effluent)
1. monitoring and alarm systems.
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Those plant processes and control technologies which at the pilot
plant, semi-works, or other level, have demonstrated both
technological performances and economic viability at a level
sufficient to reasonably justify investing in such facilities
were also considered in assessing the best available technology
economically achievable. It is the highest degree of control
technology that has been achieved and has been demonstrated to be
capable of being designed for plant scale operation. Although
economic factors are considered in this development, the costs
for this level of control are intended to be for the top-of-the
line of current technology subject to limitations imposed by
economic and engineering feasibility. However, this technology
may necessitate some industrially sponsored development work
prior tc its application.
EFFLUENT REDUCTION ATTAINABLE USING BEST AVAILABLE TECHNOLOGY
ECONOMICALLY ACHIEVABLE
Based upon the information contained in Sections III through IX
of this report, the following determinations were made on the
degree of effluent reduction attainable by the application of the
best available control technology economically achievable in the
various categories of the inorganic chemical industry.
General Water Guidelines
Process water is defined as any water contacting the reactants of
a process including contact cooling water. All values of
guidelines and limitations presented below are expressed as
thirty-day averages in units of kg of parameter per metric ton
(Its/ton) of product produced. The daily maximum limitation is
double the monthly average, as discussed in section IX. For
those subcategories which utilize impoundments to achieve no
discharge of process waste water pollutants, an untreated
discharge is allowed in the event of a catastrophic rainfall
exceeding the maximum 25 year, 2U hour rainfall event.
No discharge of process waste water pollutants to navigable
waters is attainable by the application of the best practicable
technology currently available for the following chemical
sufccategories:
aluminum chloride
aluminum sulfate
calcium carbide
calcium oxide and calcium hydroxide
hydrochloric acid
hydrofluoric acid
nitric acid
potassium metal
potassium dichromate
potassium sulfate
sodium bicarbonate
sulfuric acid
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The same effluent, reduction is required for these subcategories
based on best available technology economically ahcievable.
Calcium Chloride
Best available technology economically achievable includes
recycle of the packaging area washdown water and use of
noncontact heat exchangers. These process changes are being
planned by plant 185.
Therefore, the effluent limitations guidelines for calcium
chloride based on the application of the best available
technology economically achievable require no discharge of
process waste water pollutants to navigable waters.
Hydrogen Peroxide
a) Organic process
Best available technology for organic process hydrogen peroxide
plants is to recycle all process water. The discharged process
water presently contains hydrogen peroxide and organic solvent
which should not be detrimental to the process. Carbon
adsorption techniques may be applied if necessary prior to water
reuse. The effectiveness of this treatment for organic removal
has been widely demonstrated.
The ef fluent limitations guidelines for hydrogen peroxide
production by the organic process based on the application of the
best available technology economically achievable require no
discharge cf process waste water pollutants to navigable waters.
b) Electrolytic process
Best available technology for this process is segregation of the
process waste water from the cooling water discharge, treatment
of the relatively small amount of process waste water by
distillation. The distillate may be reused in the process. This
is feasible because the process waste water flow is only 95 1/kkg
(25 gal/ton) in the one plant using this process.
The effluent limitations guidelines for electrolytic process
hydrogen peroxide plants based on the application of the best
available technology economically achievable require no discharge
of process waste water pollutants to navigable waters.
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Sodium Carbonate
The calcium chloride raw waste load of the Solvay process is such
that 10-15 percent of it can supply the total volume of the
current U.S. market for calcium chloride, so the potential for
waste disposal through this channel may be limited. Large
capital costs are involved to bring Solvay process plants to the
capability of zero discharge, and the disposal of the by-product
calcium chloride is difficult due to its extreme solubility.
However, technology does exist to further reduce the
concentration of suspended solids in the effluent to 15 mg/1 or
tc reduce the volume of process water required.
The following limitations constitute the quantity or quality of
pollutants or pollutant properties which may be discharged after
the application of best available technology economically
achievable for soda ash produced by the Solvay process:
TSS 0.10 kg/kkg (0.20 Ib/ton)
pH within the range 6.0 to 9.0
Sodium Chloride
a) Solar evaporation process
Consistent with the effluent reduction attainable by the
application of best practicable technology, unused bitterns may
be returned to the brine source provided no additional pollutants
are added.
b) Solution brine-mining process
The major source of the discharged sodium chloride dissolved
solids waste generated at plant 030 emanates from carryover in
the barometric condensers. The best available technology
economically achievable for brine mining evaporative process
sodium chloride plants is to replace the barometric condensers
with noncontact heat exchangers and recycle the steam condensate
to the evaporators. The effluent limitations guidelines for
evaporative process sodium chloride plants based on the
application of the best available technology economically
achievable require no discharge of process waste water pollutants
to navigable waters.
Sodium Metal
Best available technology for sodium metal plants is:
a. Recycle of the wastes from cell washdowns to brine puri-
fication after removal of suspended solids.
b. Recovery of the calcium hypochlorite waste from the tail
gas scrubber as a product and recycle of water to the
scrubber, or replace the scrubber with a chlorine-burning
hydrochloric acid facility.
334
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c. Recycle the spent sulfuric acid used for drying the
chlorine to a "decomp" sulfuric acid plant or sale as a weak
acid solution.
Implementation of these technologies will eliminate the discharge
of process waste water pollutants.
The effluent limitations guidelines for sodium metal-chlorine
plants based on the application of the best available technology
economically achievable require no discharge of process waste
water pollutants to navigable waters.
Scdium Sulfite
Best available technology for sodium sulfite plants is recovery
of the sodium sulfate from the waste discharge by evaporation and
sale as a by-product or satisfactory land disposal. This should
not be too costly since the volume of effluent from plant 168,
for example, averages only 1U26.5 cu m/day (3700-7000 gal/day),
and the dissolved solids in this stream are mostly sodium
sulfate.
The effluent limitations guidelines for sodium sulfite plants
based on the application of the best available technology
economically achievable require no discharge of process waste
water pollutants to navigable waters.
Chlorine and Sodium or Potassium Hydroxide
a) Diaphragm cell process
Best practicable technology currently available for the
manufacture of chlorine and caustic soda or caustic potash by the
diaphragm cell process allows the discharge of treated wastes
from the tail gas scrubber and of neutralized spent acid from
chlorine drying. Best available technology is elimination of the
pollutant discharge by:
a. Catalytic treatment of the hypochlorite waste from the
scrubber to convert to a brine and recycle to brine
purification, recovery of the hypochlorite as a bleach
product or elimination of the scrubber and utilization of the
chlorine gas elsewhere in the plant, such as in a chlorine-
burning hydrochloric acid plant;
b. Recovery of the spent acid from chlorine drying and sale,
utilization elsewhere in the plant or return to spent
sulfuric acid plant for regeneration; and
c. Recycle of all weak brine/caustic solutions to the
process after extraction/elimination of harmful metals and
impurities.
335
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The effluent limitations guidelines for diaphragm cell chlor-
alkali plants based on the application of the best available
technology economically achievable require no discharge of
process waste water pollutants to navigable waters.
b) Mercury cell process
The same technologies cited above for diaphragm cell plants apply
tc mercury cell plants.
The effluent limitations guidelines for mercury cell chlor-alkali
plants based on the application of the best available technology
economically achievable require no discharge of process waste
water pollutants to navigable waters.
Sodium Bichromate and Sodium Sulfate
At plant 184, a total of approximately 113,000 kkg of product and
by-product are manufactured annually. The additional treatment
cost to this plant for the evaporation of the effluent to effect
zero discharge would amount to about $250,000/yr. This would
mean an approximate cost of $2.20/kkg of sodium dichromate and
scdium sulfate.
The effluent limiations guidelines for sodium dichromate and
byproduct sodium sulfate plants, based on the application of the
best available technology economically achievable require no
discharge of process waste water pollutants to navigable waters.
Titanium Dioxide
As indicated in Section VIII of this report, the additional
treatment costs projected to bring each of these processes
(chloride and sulfate) to zero discharge of process waste water
pollutants by demineralization and evaporation of regenerant
solutions are as follows:
a- Chloride process - an additional $730,000 per year for a
plant with a 24,300 kkg (27,000 ton) per year capacity or an
increase of approximately 5 percent over the costs of best
practicable technology.
b. Sulfate process - an additional $620,000 per year for a
plant with a 39/600 kkg (43,000 ton) per year capacity or an
increase of approximately 3 percent over the costs of best
practicable technology
However, evaporation of the large amounts of water necessary in
both processes would consume large amounts of energy and solid
waste disposal costs are high. The technology does exist to
further reduce the concentration of suspended solids and iron.
336
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Best available technology economically achievable consists of
water conservation and more efficient suspended solids removal
than required by the 1977 standard. The following limitations
constitute the quantity of pollutants which may be discharged
after application of the best available technology economically
achievable by titanium dioxide plants:
a. Chloride Process;
TSS 1.3 kg/kkg (2.6 Ibs/ton)
Iron 0.18 kg/kkg (0.36 Ib/ton)
pH within the range 6.0 to 9.0
b. Sulfate Process:
TSS 5.3 kg/kkg (10.6 Ibs/ton)
Iron 0.42 kg/kkg (0.8U Ib/ton)
pH within the range 6.0 to 9.0
337
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SECTION XI
NEW SOURCES PERFORMANCE STANDARDS
AND PRETHEATMENT STANDARDS,
The term "new source" Is defined in the Act to mean "any source,
the construction of which is commenced after the publication of
proposed regulations prescribing a standard of performance". The
treatment technology for new sources is evaluated by adding to
the considerations underlying the identification of best
available technology economically achievable, a determination of
what higher levels of pollution control are available through the
use of improved production processes and/or treatment techniques.
Thus, in addition to considering the best in-plant and end-of-
process control technology, new source performance standards
reflect how the level of effluent may be reduced by changing the
production process itself. Alternative processes, operating
methods or other alternatives were considered. However, the end
result of the analysis identifies effluent standards which
reflect levels of control achievable through the use of improved
production processes (as well as control technology), rather than
prescribing a particular type of process or technology which must
be employed.
The following factors were considered in assessing the best
demonstrated control technology currently available for new
sources:
(a) the type of process employed and process changes;
(b) operating methods;
(c) batch as opposed to continuous operations;
(d) use of alternative raw materials and mixes of raw
materials;
(e) use of dry rather than wet processes (including
substitution of recoverable solvents for water); and
(f) recovery of pollutants as by-products.
In addition to the effluent limitations covering discharges
directly into waterways, the constituents of the effluent
discharge from a plant within the industrial category which would
interfere with, pass through, or otherwise be incompatible with a
well-designed and operated publicly owned .activated sludge or
trickling filter waste water treatment plant were identified.
339
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EFFLUENT REDUCTION ATTAINABLE BY THE APPLICATION OF THE BEST
AVAILABLE DEMONSTRATED CONTROL TECHNOLOGIES, PROCESSES, OPERATING
METHODS OR OTHER ALTERNATIVES.
Based upon the information contained in Sections III through X of
this report, the following determinations were made on the degree
of effluent reduction attainable with the application of new
source standards for the various subcategories of the inorganic
chemicals industry.
No discharge of process waste water pollutants to navigable
waters is the new source performance standard for the following
chemical subcategories:
aluminum chloride
aluminum sulfate
calcium carbide
hydrochloric acid
hydrofluoric acid
calcium oxide and calcium hydroxide
nitric acid
potassium metal
potassium dichrornate
potassium sulfate
sodium bicarbonate
sulfuric acid
This is achievable by the application
technology currently available.
of the best practicable
The new source performance standards for the following chemicals
require no discharge of process waste water pollutants to
navigable Caters:
calcium chloride
hydrogen peroxide
sodium metal
sodium chloride
a) solution brine-mining process
This standard may be achieved by the incorporation of best
available technologies economically achievable into new sources.
The technologies, as outlined in section X, have been
demonstrated and may be included in the design of new sources.
Chlorine
New source performance standards for chlorine are based on the
application of best practicable technology currently available,
as summarized in Section IX. Metal anodes may be used to elim-
inate the discharge of lead, as required for new plants.
340
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Sodium Carbonate
An alternative process for the manufacture of soda ash with no
discharge of . process waste water pollutants exists, the mining
and processing of trona. Because of this, no discharge of
process waste water pollutants to navigable waters is the new
scurce performance standard for this manufacturing process. The
calcium chloride raw waste load of the Solvay process is such
that 10 to 15 percent of it can supply the total volume of the
U.S. market. Large capital costs are involved to fcring Solvay
process plants to the capability of no discharge, and the
disposal of the unmarketable by-product calcium chloride is
difficult due to its extreme solubility. No new Solvay process
plants have been built in forty years. The supply of trona ore
is adequate to satisfy the demand for sodium carbonate.
Sodium Chloride
The new source performance standards represent the effluent
reduction attainable by the application of the best practicable
technology currently available as described in section IX.
Sodium Bichromate and Sodium Sulfate
The new source performance standards for sodium dichromate and by
product sodium sulfate plants represent the application of best
practicable technology currently available and require good water
conservation which is possible in the construction of new
facilities.
The new source performance standards for this subcategory are:
TSS 0.15 kg/kkg (0.3 Ib/ton)
Cr(T) 0.0044 kg/kkg (0.0088 Ib/ton)
Cr(+6), 0.0005 kg/kkg £0.001 Ib/ton)
pH within the range 6.0 to 9.0
Titanium Dioxide (Chloride and Sulfate Processes)
Although research is currently being conducted to determine the
feasibility of acid recovery and recycle of process water, many
problems remain unsolved. As such, it is not considered feasible
tc require this technology to be incorporated into new
facilities. The new source performance standards for titanium
dioxide require the same degree of effluent reduction attainable
by the application of best available technology economically
achievable, as presented in Section X. This technology is
demonstrated and may be applied to new sources.
PRETHEATMENT STANDARDS FOR NEW SOURCES
Plants whose waste water discharges are characterized by the
presence of materials that interfere with operation of biological
systems are not suited to use of conventional secondary waste
341
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treatment. Extreme segregation (that isp limiting the sewered
discharge to sanitary and other organic wastes) cr pretreatment
is required by such manufacturing plants.
The pretreatment standards for new sources in the inorganic
chemicals manufacturing category are the standards set forth in
UO CFR 128. In addition to these standards, however, the
pretreatment standard for incompatible pollutants is the new
source performance standard, if a publicly owned treatment works
is committed to remove a specified percentage of any incompatible
pollutant, the pretreatment standard is correspondingly reduced
in stringency for that pollutant.
342
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SECTION XII
ACKNOWLEDGMENTS
The Environmental Protection Agency would like to thank Dr. R.
Shaver, Dr . C. L . Parker and Me ssrs. E. F. Afcrams, L. C.
McCandless, R. C. Smith, Jr. and E. F. Rissmann of Versar Inc.
for their aid in the preparation of this Document.
The following members of the EPA working group/steering committee
are acknowledged for their advice and assistance:
W. J. Hunt Effluent Guidelines Division
J. A. Hemminger Effluent Guidelines Division
G. Rey Office of Research and Monitoring
H. Skovrenek National Environmental Research Center
J. Savage Office of Planning and Evaluation
A. Eckert Office of General Counsel
G. Amendola Region V
J. Davis Region III
E. Lazar Office of Solid Waste Management Programs
The author wishes to thank his associates in the Effluent
Guidelines Division for their assistance, particularly Messrs.
Allen Cywin, Ernst P. Hall and Walter J. Hunt.
James A. Hemminger, Effluent Guidelines Division, handled a large
portion of the rewriting and reorganizing of the Document, as
well as the preparation of the associated Fede_r.£i Register
publications. His assistance is appreciated.
Appreciation is also extended, to Ms. Kaye Starr and Ms. Nancy
Zrubek for the long hours spent typing and retyping this
Document. The helpful suggestions and advice offered by EPA
personnel in Regional offices are also appreciated.
Appreciation is also extended to the following trade associations
and corporations for their assistance and cooperation:
Chlorine Institute
Manufacturing Chemists Association
Salt Institute
Water Pollution Control Federation
Airco Corporation
Alcoa .Industries
Allied Chemical Corporation
American Cyanamid Corporation
Aqua-Chem
BASF Wyandotte Chemicals Corporation
Bird Machine Company
343
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Cabot Corporation
Calgon corporation
Chemical Separations Corporation
Diamond Shamrock Chemical Company
Dorr Oliver, Inc.
Dow Chemical Company
E.I. DuPont de Nemours 5 Company
Duval Corporation
Eimco Division, Envirotech Corporation
Envirogenics Company
Essex Chemical Corporation
Ethyl Corporation
FMC Corporation
Freeport Sulfur company
Goslin Birmingham, Inc.
Gulf Environmental Systems company
Harshaw Chemical Company
Hooker Chemical Company
International Mineral 6 Chemical Corp.
International Salt Company
Kaiser Aluminum and Chemical Corporation
Leslie Salt Company
Midwest Carbide Corporation
Monsanto Company, Inc.
Morton Salt Company
MSA Research, Inc.
National Lead Industries
New Jersey Zinc Company
occidental Petroleum Corporation
Office of Saline Water, U.S. Department of Interior
Olin Corporation
Pearsall Chemical Company
Potash Institute of America
PPG Chemical Industries
Resources Conservation Company
Rice Engineering and Operating, Inc.
RMI Corporation
Rohm and Haas Company
Sherwin Williams Company
Stauffer Chemical Company
Union Carbide Corporation
U.S. Borax Corporation
U.S. Bureau of Mines, Peno Research Center
U.S. Lime, Division Flintkote Company
Van de Mark Chemical company. Inc.
Vicksburg Chemical
Water Services Corporation
Davy Power Gas, Inc.
344
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SECTION XIII
REFERENCES
tReferences 1-12 were used to characterize the industry and
develop its profile and statistics in Sections III and IV1
1. Popper, H., "Modern Cost Engineering Techniques", McGraw-Hill
Book Cc,, 1970.
2. Shreve, R.N., "Chemical Process Industries", 3rd Ed., McGraw-
Hill Book Co., 1967.
3. Perry, J.N., "Chemical Engineer's Handbook", 4th Ed., McGraw-
Hill Book Co., 1962.
4. Kirk, R.E. and Othmer, D.F., "Encyclopedia of Chemical Tech-
nology", 2nd Ed., Wiley-interscience, 1963.
5. Faith, W.L., Keyes, D.B., and Clark, R.L., "Industrial
Chemicals", 3rd Ed., John Wiley & sons. Inc. (1965).
6. Keyes, D.B. and Deem, L.G., "Chemical Engineer's Manual",
Prof. Ed., John Wiley 5 Sons, Inc. (1942).
7. Davidson, R.L., "Successful Process Plant Practices", McGraw-
Hill Book Co. (1958).
8. U.S. Bureau of Mines, "producers of Salt in the United states-
1965".
9. Hicks, T.G., "Standard Handbook of Engineering Calculations",
McGraw-Hill Book Co. (1972).
10. Chemical and Engineering News, June 4, 1973, pp. 12-13,
11. "Study of the Economic Impact of the Cost of Alternative
Federal Water Quality Standards on Ten Inorganic Chemicals",
Borz-Allen Public Administration services. Inc., Washington,
D.C. (1973) .
12. Chemical Marketing Reporter, June 4, 1973. '
13. "Methods of Chemical Analysis for Water and Wastes", FWPCA,
p. 72 (1971).
14. Banksdale, J., "Titanium", The Ronald Press Company, New York,
N.Y., 2nd Edition.
15. Fairall, J.M., Marshall, L.S., Rhines, C.E., "Guide for
Conducting an Industrial Waste Survey", Draft only, U.S.
345
-------
Environmental Protection Agency, Cincinnati, Ohio (1972).
16. Sawyer, Clair N., "Chemistry for Sanitary Engineers", McGraw-
Hill Book Co., New York, N.Y. (1960).
17. "Public Health Service Drinking Water Standards", Revised
1963, U.S. Department of Health, Education and Welfare,
U.S. Public Health Service Publication No. 956, U.S.
Government Printing Office, Washington, D.C. (1962).
18. "Chemical and Engineering News", May 7, 1973, pp. 8-9.
19. "The Economics of Clean Water", Vol. Ill, Inorganic Chemicals
Industry Profile, U.S. Dept. of the Interior, Federal water
Pollution Control Administration (March 1970).
20. Final Technical Report, Contract No. 68-01-0020, Industrial
Waste Study of Inorganic Chemicals, Alkalis and chlorine.
General Technologies Corp., July 23, 1971 (EPA).
21. Chemical and Engineering News, February 19, 1973, pp. 8-9.
22. Besselievre, Edward P., "The Treatment of Industrial Wastes",
McGraw-Hill Book CO., p. 56 (1968).
23. Personal Communications, EIMCO Division, Enviro-Tech Corp.,
Salt Lake City, Utah.
2U. Personal Communications, Dorr-Oliver Co., Stamford Conn.
25. "The Economics of Clean Water", Vol. Ill, Inorganic Chemicals
Industry Profile, Contract No. 14-12-592, U.S. Department of
the Interior, Federal Water Pollution Control Administration
(March, 1970).
26. "Sludge Dewatering: The Hardest Phase of Waste Treatment",
Environmental Science and Technology, Vol. 5, No. 8, August
1971, pp. 670-671.
27, Jacobs, H.L., "In Waste Treatment — Know Your Chemicals,
Save Money", Chemical Engineering, May 30, 1960, pp. 87-91.
28. sonnichsew, J.C., Jr., Engstrom, S.L., Kolesar, D.C. and
Bailey, G.C., "Cooling Ponds - A Survey of the State of
the Art", Hanford Engineering Development Laboratory,
Report HEDL-TME-72-101 (Sept. 1972).
29. Unpublished Information, E.I. DuPont Letter (May 3, 1973).
30. Unpublished Information, E.I. DuPont Letter (May 16, 1973).
31. Kumar, J., "Selecting and Installing Synthetic Pond-Linings",
346
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Chemical Engineering, February 5, 1973, pp. 67-68.
32. Rapier, P.M., "ultimate Disposal of Brines From Municipal
Wastewater Renovation", Water-1970, Chemical Engineering
Progress Symposium Series 107, Vol. 67, p. 340-351.
33. Browning, Jon E., "Activated Carbon Bids for Wastewater
Treatment Jobs", Chemical Engineering, sept. 7, 1970,
pp. 32-34.
34. "New Treatment Cuts Water Bill", Chem. Week, June 10, 1970,
p. 40.
35. Ahlgren, Richard M., "Membrane vs. Resinous Ion-Exchange
Demineralization", Industrial Water Engineering, Jan. 1971,
pp. 12-15.
36. Crits, George J., "Economic Factors in Water Treatment",
Industrial Water Engineering, Oct. 1971, pp. 22-29.
37. "Applications of Ion Exchange", 111, Rohm & Haas Bulletin
No. 94, July 16-18, 1969.
38. Higgins, I.R. and Chopra, R.C., "Chem-Seps Continuous Ion-
Exchange Contactor and its Application to De-mineralization
Processes", Presentation, Conf. of Ion Exchange in the
Process Ind., Imperial Coll, of Sci. £ Tech., London, July
16-18, 1969.
39. Kunin, Robert and Downing, Donal"d G., "New ion Exchange
Systems for Treating Municipal and Domestic Waste Effluents",
Water-1970, Chem. Eng. Prog. Synu Series 107, Vol. 67, pp.
575-580 (1971).
40. Downing, D.G., Kunin R., and Polliot, F.X., "Desal Process-
Economic Ion Exchange System for Treating Brackish and Acid
Mine Drainage Waters and Sewage Waste Effluents", Water-1968,
Chem. Eng. Prog. Sym. Series 90, vol. 64 (1968).
41. Parlante, R., "Comparing Water Treatment Costs", Plant
Engineering (May 15, 1969).
42. Brigham, E.G. and Chopra, R.C., "A Closed Cycle Water System
for Ammonium Nitrate Producers", presented. Int. Water Conf.,
The Eng. Soc. of western Penn., 32nd Annual Meeting,
Pittsburgh, Pa, (November 4, 1971).
43. Holzmacher, Robert G., "Nitrate Removal from a Ground water
Supply", Water and Sewage world (reprint).
44. "Ion Exchangers Sweeten Acid Water", Envir. Sci. & Tech.,
tfol. 5, No. 1 pp. 24-25 (January 1971).
347
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45. Sawyer, George A., "New Trends in Wastewater Treatment and
Recycle", Chemical Engineering, pp. 120-128 (July 24, 1972).
46. Dryden, Franklin D. , "Demineralization of Reclaimed Water",
Ind. Water Eng., pp. 24-26 (August/September, 1971).
47. Seels, Frank H., "Industrial Water Pretreatment", Chemical
Engineering DesJcbook Issue (February 26, 1*573) .
48. Calmon, Calvin, "Modern Ion Exchange Technology", Ind. Water
Eng., pp. 12-15 (April/May 1972).
49. "Demineralizing, Dealkalinization, Softening", Chemical
Separations corporation Bulletin.
50. "Reverse Osmosis Principles and Applications", text by Roga
Systems Division Staff, Gulf Environmental Systems Company,
P.O. Box 608, San Diego, California, 92112.
51. Kremen, S.S., "The Capabilities of Reverse Osmosis for
Volume Production of High-Purity Water and Reclamation of
Industrial Wastes" for Thirty-Second Annual Meeting of the
American Power Conference, Chicago, 111. (April 21-23, 1970).
52. Cruver, J.E. and Nusbaum, I., "Application of Reverse Osmosis
to Wastewater Treatment", presented at Water pollution
Control Federation Meeting, Atlanta, Georgia (Oct. 8-13, 1972).
53. Kaup, Edgar C., "Design Factors in Reverse Osmosis", Chemical
Engineering, Vol. 80, No. 8, pp. 46-55 (April 2, 1973) .
54. Myers, J.H., "Reverse Osmosis Can Cut Cost of water Treatment",
Industrial Water Engineering, pp. 25-30 (March 1970).
55. Rowland, H., Nusbaum, I. and Jester, F.J., "Consider RO for
Producing Feedwater", Power, pp. 47-48 (December 1971).
56, Witmer, F.E., "Low Pressure'RO Systems - Their Potential in
Water Reuse Applications", paper presentation at Joint EPA-
AICHE Water Reuse Meeting, Washington, D.C. (April 23-27, 1973)
57. Channabasappa, K-C. and Harris, F.L., "Economics of Large-
scale Reverse Osmosis Plants", Ind. Water Eng., pp. 40-44
(October 1970) .
58. Resources conservation Co., unpublished data and engineering
design and cost information.
59. Herrigel, H., Fosberg, T., Stickney, W. and Perry C., Final
Report, "Operating Data of a Vertical Plane Surface, Falling
Film Evaporator Using Slurry and High Concentration Feeds",
348
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OSW Contract No. 14-30-2939.
60. "El Paso Natural Participates in Promising Process for Water
Recovery", The Pipeliner (December 1971).
61. Casten, James, Goslin-Birmingham Corp., unpublished data and
engineering design and cost information.
62. Prescott, J.H., "New Evaporation-Step Entry", Chemical
Engineering, pp. 30-32 (Dec. 27, 1971) .
63. "Industrial Wastewater Reclamation with a 400,000 Gallon-Per-
Day Vertical Tube Evaporator, Design, Construction, and
Initial Operation", EPA Program No. 12020 GUT.
64. "Evaporator Tackles Wastewater Treatment", Chemical Engin-
eering, p. 68 (March 20, 1972) .
65. Cosgrove, J. , "Desalting: Future Looks Bright", Water and
Wastes Engineering, Vol. 9, No. 8, p. 43.
66. Houle, J.F. and Challis, J.A., "Industrial Use of Desalting
in Southern Puerto Rico", Water-1970, Chem. Eng. Prog. Sym.
Series 107, vol. 67 (1971).
67. Patterson, J. and Minear, Roger A., "Wastewater Treatment
Technology", 2nd Edition, Report to Inst. of Envir. Cont.,
State of Illinois, pp. 321-343 (January 1973).
68, "The Economics of Clean water". Vol. Ill Inorganic Chemicals
Industry Profile, Contract No. 14-12-592, U.S. Dept of the
Interior, Federal Water Pollution Control Administration,
pp. 445-447 (March 1970).
69. Okey, Robert W., Envirogenics Company, Letter (May 14, 1973),
70, Gavelin, Gunnar, "Is Evaporation the Ultimate Solution to
Effluent Problems?" paper Trade Journal, pp. 102-103 (June
10, 1968).
71. Ahlgren, Richard M., "A New Look at Distillation", Ind.
Water Eng., pp. 24-27 (October 1968).
72. Young, K.G,, "Summary of Design and Economic Considerations
for Complete Drying and Disposal of the Inorganic Salt
Slurry Produced by the RCC M225B Brine concentrator",
Resources Conservation Company, Unpublished Analysis. (Using
Reference 72).
73. W.L. Badger Associates, "Conversion of Desalination Plant
Brines to solids", OSW Contact Report f636 (October 1970).
349
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74. Witt, Phillip A., Jr., "Disposal of Solid Wastes", Chemical
Engineering, pp. 67-77 (October 4, 1971).
75. Unpublished Data, E.I. DuPont Company-
76. Goodheart, L.B., Rice Engineering & Operating, Inc., General
Cost Letter (May 4, 1973).
77. "Well-Disposal is No Panacea", Chemical Engineering, pp. 26-28
(May 1972) .
78. Wright, J.L., "Disposal Wells are a worthwhile Risk", Mining
Engineering, pp. 63-72 (August 1970).
79. Ramey, B.J., "Deep-Down waste Disposal", Mech. Eng., pp. 28-31
(August 1968).
80. "Injection Wells Pose a Potential Threat", Envir. Sci. & Tech.,
Vol. 6, No.2, pp. 120-122 (February 1972).
81. "The Economics of Clean Water", Vol. Ill, Inorganic Chemicals
Industry Profile. Contract No. 14-12-592, Federal Water Poll.
Control Admin., U.S. Department of the Interior (March 1970).
82. Fader, Samuel w., "Barging Industrial Liquid Wastes to Sea",
J. Water Poll. Control Fed., Vol. 44, No. 2, pp. 314-318
(February 1972).
83. "At Sea About Chemical Wastes", Chemical Week, pp. 133-136
(October 14, 1967).
•;
84. "Tide May be Going Out for Waste Disposal at Sea", Chemical
Week, pp. 49-53 (October 28, 1970).
85. Unpublished Data, E.I. DuPont Co., Letter and verbal commun-
ications (May 16, 1973).
350
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SECTION XIV
GLOSSARY
Acidity
The total titratable hydrogen ion content of the solution is
defined as the acidity.. Acidity is expressed in mg/1 of free
hydrogen ion.
Adsorption
Condensation of the atoms, ions or molecules of a gas, liquid or
dissolved substance on the surface of a solid called the
adsorbent. The best known examples are gas/solid and liquid/
solid systems.
Air Pollution
The presence in the air of one or more air contaminants in
quantities injurious to human, plant, animal life. Or property,
or which unreasonably interferes with the comfortable enjoyment
thereof.
Alkalinity
Total titratable hydroxyl ion concentration of a solution. In
water analysis, alkalinity is expressed in mg/1 (parts per mill-
ion) of calcium carbonate.
The solid residue left after incineration in the presence of
oxygen.
Bag^ Filter
A dry collection device for recovery of particulate matter from
gas streams.
Barometric Condenser
Device, operating at barometric pressure, used to change vapor
into liquid by cooling.
Slowdown
The minimum discharge of recirculating water for the purpose of
discharging materials contained in the water, the further build-
up of which would cause concentration in amounts exceeding limits
established by best engineering practice.
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Apparatus used to remove entrained solids and other substances
from a gas stream.
Hardness (Total)
The characteristic of water generally accepted to represent the
total concentration of calcium and magnesium ions, usually
expressed as mg/1 of calcium carbonate.
Heavy Metal
One of the metal elements not belonging to the alkali or alkaline
earth group. In this study, the classification includes
titanium, vanadium, iron, nickel, copper, mercury, lead, cadmium,
and chromium.
Ion Exchange
A reversible chemical reaction between a solid and a fluid by
means of which ions may be interchanged from one substance to
another. The customary procedure is to pass the fluid through a
bed of the solid, which is granular and porous and has a limited
capacity for exchange. The process is essentially a batch type
in which the ion exchanger, upon nearing depletion, is
regenerated by inexpensive salts or acid.
Kiln (Rotary)
A large cylindrical mechanized type of furnace used for calcin-
ation.
Membrane
A thin sheet of synthetic polymer, through the apertures of which
small molecules can pass, while larger ones are retained.
Mother liquor
The solution from which crystals are formed.
Multi-Effect Evaporator
In chemical processing installations, requiring a series of
evaporations and condensations, the individual units are set up
in series and the latent heat of vaporization from one unit is
used to supply energy for the next. Such units are called
"effects" in engineering parlance as, e.g., a triple effect
evaporator.
Oleum or. Fuming Sulfuric Acid
A solution of sulfur trioxide in sulfuric acid.
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Is a measure of the relative acidity or alkalinity of water. A
pH value of 7.0 indicates a neutral condition; less than 7
indicates a predominance of acids, and greater than 7, a pre-
dominance of alkalis. There is a 10-fold increase (or decrease)
from one pH unit level to the next, e.g., 10-fold increase in
alkalinity from pH 8 to pH 9-
Plant Effluent or Discharge after Treatment
The waste water discharged from the industrial plant. In this
definition, any waste treatment device (pond, trickling filter,
etc.) is considered part of the industrial plant.
Pretreatment
The necessary processing given materials before they can be
properly utilized in a process or treatment facility.
Process Effluent or
The volume of waste water emerging from a particular use in the
plant.
Process Water
Water which is used in the internal plant streams from which
products are ultimately recovered, or water which contacts either
the raw materials or product at any time.
Reverse Osmosis
A method involving application of pressure to the surface of a
saline solution forcing water from the solution to pass from the
solution through a membrane which is too dense to permit passage
of salt ions. Hollow nylon fibers or cellulose acetate sheets
are used as membranes since their large surface areas offer more
efficient separation.
Sedimentation
The falling or settling of solid particles in a liquid, as a
sediment.
Settling Pond
A large shallow body of water into which industrial waste waters
are discharged. Suspended solids settle from the waste waters
due to the large retention time of water in the pond.
Sintering
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The agglomeration of powders at temperatures below their melting
points. Sintering increases strength and density of the powders.
Slaking
The process of reacting lime with water to yield a hydrated
product.
The settled mud from a thickener clarifier. Generally, almost
any flocculated, settled mass.
Slurry
A watery suspension of solid materials.
Sniff Gas
The exhaust or tail gas effluent from the chlorine liquefaction
and compression portion of a chlor-alkali facility.
Solute
A dissolved substance.
Solvent
A liquid used to dissolve materials.
Thickener
A device or system wherein the solid contents of slurries or
suspensions are increased by evaporation of part of the liquid
phase, or by gravity settling and mechanical separation of the
phases.
Total Dissolved Solids (TDS)
The total amount of dissolved solid materials present in an
aqueous soluti on.
Total Organic Carbon, TOC
A measurement of the total organic carbon content of surface
waters, domestic and industrial wastes, and saline waters.
Total Suspended Solids (TSS)
Solid particulate matter found in waste water streams, which, in
most cases, can be minimized by filtration or settling ponds.
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Turbidity
A measure of the opacity or transparency of a sediment-containing
waste stream. Usually expressed in Jackson units or Formazin
units which are essentially equivalent in the range below 100
units.
Wet Scrubbing
A gas cleaning system using water or some suitable liquid to
entrap particulate matter, fumes, and absorbable gases.
Waste Discharged
The amount (usually expressed as weight) of some residual sub-
stance which is suspended or dissolved in the plant effluent.
Waste Generated (Raw Waste)
The amount (usually expressed as weight) of some residual sub-
stance generated by a plant process or the plant as a whole.
This quantity is measured before treatment.
Water Recirculation_ or Recycling
The volume of water already used for some purpose in the plant
which is returned with or without treatment to be used again in
the same or another process.
Water Use
The total volume of water applied to various uses in the plant.
It is the sum of water recirculation and water withdrawal.
Water Withdrawal or Intake
The volume of fresh water removed from a surface or underground
water source by plant facilities or obtained from some source
external to the plant. The effluent limitations guidelines for
sodium dichromate and byproduct sodium sulfate plants, based on
the application of the best available technology economically
achievable, require no discharge of process waste water
pollutants to navigable waters. 9992;G
357 MS. GOVERNMENT PRINTING OFFICE: 1974 546-317/306 1-3
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