KP*
GRI
Development Document for
Interim Final Effluent Limitations Guidelines
and New Source Performance Standards
for the
SIGNIFICANT ORGANIC PRODUCTS
Segment of the
ORGANIC CHEMICAL MANUFACTURING
Point Source Category
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
NOVEMBER 1975
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DEVELOPMENT DOCUMENT
for
INTERIM FINAL EFFLUENT LIMITATIONS
and
NEW SOURCE PERFORMANCE STANDARDS
for the
SIGNIFICANT ORGANIC PRODUCTS SEGMENT
Of the
ORGANIC CHEMICALS MANUFACTURING
POINT SOURCE CATEGORY
Russell E. Train
Administrator
Andrew W. Breidenbach, Ph.D.
Acting Assistant Administrator
for Water and Hazardous Materials
y"!*'4**
Allen Cywin, Director
Effluent Guidelines Division
John A. Nardella, Project Officer
Effluent Guidelines Division
November, 1975
Effluent Guidelines Division
Offj.ce of Water and Hazardous Materials
U.S. Environmental Protection Agency
Washington, D.C. 20460
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ABSTRACT
A study of the significant organic products segment of the
organic chemicals manufacturing industry was conducted by
Roy F. weston. Inc. for the United States Environmental
Protection Agency. The purpose of this study was to
establish effluent limitations guidelines for existing
point-source discharges and standards of performance and
pretreatment standards for new sources. This study and
proposed regulations were undertaken in fulfillment of
Sections 301, 304, 306, and 307 of the Federal Pollution
Control Act Amendments of 1972.
For the purposes of this study, 55 product/process segments
of the industry were investigated. Effluent limitations
guidelines were developed for 27 of these product/process
segments. Other 28 product/processes are currently being
reviewed to determine the possible economic impact and will
be published at a later date. This study was the second
part of a two phase effort. In the first phase, process raw
waste loads and effluent limitations guidelines were
established for 40 product/process groups. Coverage of the
industry has now been extended to include 67 product/process
segments.
In this studies, product/process groups were subcategorized
into four major subcategories. Effluent limitations and
guidelines were then determined for each product/process by
multiplying the raw waste load by an appropriate reduction
factor or concentration. The resultant limit is considered
a long term or design limit. In order to convert the design
limit to the daily maximum and 30 day maximum average the
design limit is multiplied by an appropriate variability
factor.
Supportive data and the rationale for development of the
proposed effluent limitations guidelines and standards of
performance are contained in this report.
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CONTENTS
Section Page
I CONCLUSIONS 1
II RECOMMENDATIONS 5
III INTRODUCTION 21
IV INDUSTRY CATEGORIZATION 41
V WASTE CHARACTERIZATION 255
VI SELECTION OF POLLUTANT PARAMETERS 261
VII CONTROL AND TREATMENT TECHNOLOGIES 291
VIII COST, ENERGY AND NONWATER QUALITY ASPECTS 341
IX BEST PRACTICABLE CONTROL TECHNOLOGY 345
CURRENTLY AVAILABLE (BPCTCA)
X BEST AVAILABLE TECHNOLOGY ECONOMICALLY 355
ACHIEVABLE (BATEA)
XI NEW SOURCE PERFORMANCE STANDARDS-BEST 359
AVAILABLE DEMONSTRATED CONTROL TECHNOLOGY
(BADCT)
XII PRETREATMENT GUIDELINES 363
XIII VARIABILITY IN TREATMENT 367
PLANT PERFORMANCE
XIV ACKNOWLEDGMENTS 371
XV BIBLIOGRAPHY 373
XVI GLOSSARY AND ABBREVIATIONS 385
11
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FIGURES
figure
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4-10
4-11
4-12
4-13
4-14
4-15
4-16
4-17
4-18
4-19
4-20
4-21
4-22
Title
Flow Diagrams
Cumene
p-Xylene
Chlor obenz en e
Chlorobenzene (incl. dichlorobenzene)
Chlorinated Methanes
Chlor otoluene
Dipheny 1 amine
Perchloroethylene
Phthalic Anhydride (o-Xylene)
Phtnalic Anhydride (Naphthalene)
Hexamethylenediamine (Adiponitrile)
Hexamethylenediamine (Hexanediol)
Methyl Ethyl Ketone
Tricresyl Phosphate
Adiponitrile
Benzoic Acid and Benzaldehyde
Methyl Chloride
Maleic Anhydride
Acetic Esters
Propylene Glycol
Caprolactam (DSM)
Cyclohexanone Oxime
Page
48
50
54
55
59
62
65
69
73
77
81
85
89
92
96
101
105
108
113
118
121
125
111
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Figures Page
4-23 Formic Acid 131
4-24 Isopropanol 134
4-25 Oxalic Acid 138
4-26 Calcium Stearate 141
4-27 Hexamethylene Tetramine (Plant 1) 144
4-28 Hexamethylene Tetramine (Plant 2) 145
4-2-9 Hydrazinfi 149
4-30 Isobutylene 152
4-31 Sec-Butyl Alcohol 155
4-32 Acrylonitrile 158
4-33 Cresol 161
4-34 p-Aminophenol 165
4-35 Propylene Oxide 169
4-36 Pentaerythritol 173
4-37 Saccharin 176
4-38 o-Nitroaniline 179
4-39 p-Nitroaniline 182
4-40 Pentachlorophenol 185
4-41 Fatty Acids and Primary Derivatives 192
4-42 lonone and Methylionone 207
4-43 Methyl Salicylate 210
4-44 Citroneilol and Geraniol 214
4-45 Plasticizers 217
4-46 Pigments 231
4-47 Citric Acid 234
IV
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Figures Page
4-48 Naphthenic Acid 239
4-49 Monosodium Glutamate 242
4-50 Tannic Acid 247
4-51 Vanillin 251
7-1 BPCTCA Waste Treatment Model 335
7-2 BATEA Waste Treatment Model 336
v
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TABLES
Table Title Page
2-1 Subcategories of the Secondary Organic 7
Products Segmentof tlie Organic Chemicals
Manufacturing Industry
2-2 Effluent Limitations for Best 10
Practicable Control Technology
Currently Available (BPCTCA)
2-3 Effluent Limitations for Best 13
Available Technology Economically
Achievable (BATEA)
2-4 Standards of Performance for New 17
Organic Chemicals Manufacturing
Sources
3-1 Chemicals Listed under SIC Code 2865 24
3-2 Chemicals Listed under SIC Code 2869 27
4-1 Process Raw Waste Load Based on DSM 128
Process
4-2 Process Raw Waste Load Based on DSM 129
Process
4-3 Some Examples of Commercial Fatty 189
Acids Showing Typical Percentage
of Constituent Acids
4-4 Chemical Conversions and Unit Opera- 202
tions Contributing to Process Raw
Waste Loads for the Manufacture of
Fatty Acids and Primary Derivatives
4-5 Process RWL Associated with Manu- 204
facture of Fatty Acids
4-6 Process RWL Associated with Manu- 205
facture of Primary Derivatives from
Fatty Acids
4-7 RWL Data for Batch Chemical Complex 212
4-8 Usage Classification of Dyes 221
VI
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Tables Page
4-9 Chemical Classification of Dyes 223
4-10 U.S. Production of Dyes by Classes 224
of Application, 1965
4-11 U.S. Production and Sales of Dyes 225
by Chemical Classification, 1964
5-1 Subcategory A - Product-Process 257
Raw waste Loads
5-2 Subcategory B - Product-Process 257
Raw Waste Loads
5-3 Subcategory C - Product-Process 258
Raw Waste Loads
5-4 Subcategory D - Product-Process 259
Raw Waste Loads
6-1 List of Pollutants Analyzed for the Organic 262
Chemicals Industry
6-2 Miscellaneous RWL for Subcategory A 269
6-3 Miscellaneous RWL for Subcategory B 270
6-4 Miscellaneous RWL for Subcategory C 273
6-5 Miscellaneous RWL for Subcategory D 275
7-1 Organic Chemicals Study Treatment 299
Technology Survey
7-2 Historic Treatment Plant Performance 321
50 Percent Probability of Occurrence
7-3 Treatment Plant Survey Data 322
7-4 Effectiveness of Filtration Test on 328
Biological Treatment Effluent
7-5 Organic Chemical Plants Using Activated 330
Carbon to Treat Raw Wastewaters
7-6 Summary COD Carbon isotherm Data 331
vn
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Tables Page
7-7 Summary TOC Carbon Isotherm Data 332
7-8 Summary TOC and COD Carbon Exhaustion Rates 333
8-1 Summary of Waste Treatment Costs for 342
BPCTCA, BATEA, and BADCT
9-1 Development of Effluent Limitations for the 353
Secondary Organic Products Segment of the Organic
Chemicals Point Source Category by Application
of the Best Practicable control Technology
Currently Available (BPCTCA)
10-1 Development of Effluent Limitations for the 358
Secondary Organic Products Segment of the Organic
Chemicals Point Source Category by Application of
tne Best Available Technology Economically
Achievable (BATEA)
11-1 Development of Standards of Performance for 361
the Secondary Organic Products Segment of the
Organic Chemicals Point source Category by
Application of the Best Available Demonstrated
Control Technology
12-1 Pretreatment Unit Operations for the 365
Organic Chemicals Industry
Vlll
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SECTION I
CONCLUSIONS
The complex task of establishing effluent guidelines
limitations for the organic chemicals industry required that
the industry be divided into a two-phase study. The final
Phase I development document was issued in April 1974. That
document recommended the use of process-oriented sub-
categories which were developed as follows:
Continuous Nonagueous Processes {Phase I Subcategory A)
Contact between water and reactants or products is minimal.
Water is not required as either reactant or diluent, and is
not formed as a reaction product. The only water usage
stems from periodic washes or catalyst hydration.
Continuous Vapor Phase Processes Where Contact Process
Water is used as Diluent, Quench or Vent Gas Absorbent
(Phase I Subcateqory B)
Process water is generated through the use of diluent steam,
product quench or vent gas absorption. Process reactions
are all vapor-phase over solid catalysts. Most processes
use a vent gas absorber, coupled with steam stripping of
chemicals for purification and recycle of the absorber
water.
Continuous Aqueous Liquid-Phase Reaction Systems
(Phase I Subcategory C)
Process reactions are liquid-phase, with the catalyst in the
aqueous medium. Continuous regeneration of the catalyst
requires extensive water usage, and substantial removal of
spent catalyst and inorganic by-products may be required.
Additional - process water is involved in final purification
and/or neutralization of products.
Batch and Semi-Continuous Processes (Deleted from Phase I
but covered under Phase II)
Many reactants are in the liquid-phase with aqueous catalyst
systems. Requirement for very rapid process cooling
necessitates provisions for the direct addition of contact
quench water or ice. Reactants and products are transferred
from one piece of equipment to another by gravity flow,
pumping, or pressurization. Much of the materials handling
is manual, and there is only limited use of automatic
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process control. Filter presses and centrifuges are
commonly used for solid-liquid separations, and air or
vacuum ovens are used for drying. Cleaning of non-
continuous production equipment constitutes a major source
of waste water.
The criteria established for these four industry
subcategories was also used in the Phase II study. The 40
product/process segments covered in the Phase I study were
further subcategorized into seven subgroups: A, Bl, B2, Cl,
C2t C3, and C4. Effluent limitations were then calculated
on the basis of the mean subcategory group raw waste load.
In the Phase II study, the effluent limitations were
established on the individual product/process raw waste load
rather than on the mean for the subcategory group. Twenty-
seven product/process segments of the 55 product/processes
investigated were selected for establishment of effluent
limitations. A preliminary economic analysis indicated that
there may be a possible adverse impact for 19
product/processes. More detailed analysis is currently
underway to firmly establish the extent of any possible
impact and the possibility of establishing effluent
limitations in the future. For seven other
product/processes, the data base was not considered
satisfactory to support effluent limitations at this time.
Many RWL parameters were considered during the study, and
specific pollutants which might be inhibitory or
incompatible with biological treatment systems were cited in
Section VI. Effluent limitations and standards for cyanide
were established for hexamethylenediamine, adiponitrile and
acrylonitrile product/processes. Total copper limitations
were also established for the plasticizers segment.
End-of-process treatment for the 1977 standard is defined as
equivalent to biological treatment as typified by current
exemplary processes such as activated sludge, trickling
filters, aerated lagoons, and anaerobic lagoons. These
systems may require pH control and equalization in order to
control variable waste loads, and also will require good
clarification with the addition of chemicals to aid in
removing suspended solids. These systems do not preclude
the use of equivalent chemical-physical systems such as
activated carbon. Additionally, suitable in-process
controls may be needed for the control of those pollutants
which may be inhibitory to the biological waste treatment
system and for possible reduction of raw waste loads.
Best available technology economically achievable, BATEA,
(1983 Standard) is based on the addition of activated carbon
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treatment following biological treatment. This technology
permits substantial reductions of dissolved organic
pollutants which are biorefractory as well as many which are
biodegradable. The application of exemplary in-process
systems is also considered to be applicable to this
technology. End-of-process activated carbon treatment does
not preclude the use of such treatment as an in-process
technology.
End-of-process technology for new sources utilizing the best
available demonstrated control technology (BADCT) is defined
as equivalent to biological treatment with suspended solids
removal via clarification, sedimentation, sand, or dual-
media filtration. In addition, the use of exemplary in-
process controls are assumed to be applicable, particularly
where biotoxic pollutants must be controlled. This
technology does not preclude the use of equivalent chemical-
physical systems such as activated carbon as either an in-
process or end-of-process treatment. The use of chemical-
physical systems may be necessary in areas where land
availability is limited.
Time based effluent limitations were derived as the maximum
parameter value for any one day and the maximum average of
daily values for any period of thirty consecutive days. The
factors used in deriving these -time-based limitations were
determined from long-term performance (i.e. daily, weekly,
monthly) from the best treatment systems evaluated. Time
based limitations consider the normal variations of
exemplary designed and operated waste treatment systems and
include allowances for expected variation by use of suitable
variability factors.
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SECTION II
RECOMMENDATIONS
Effluent limitations defining best practicable control
technology currently available are presented for each
industrial subcategory of the organic chemicals
manufacturing industry. Product-process segments of the
industry which were covered in this study are listed in
Table 2-1. Those product/process segments for which
effluent limitations and guidelines are recommended are
indicated in Table 2-1 as well as the 28 product/processes
for which effluent limitations and guidelines are not
proposed at this time. Effluent limitations for the 1977
Standards (BPCTCA) are shown in Table 2-2 for the 27
designated product/processes. Process waste waters subject
to these limitations include all contact process water but
do not include noncontact sources such as boiler and cooling
water blowdown, and other similar sources.
Implicit in BPCTCA RWL data is the segregation of noncontact
waste waters from process waste waters and the maximum
utilization of applicable in-plant pollution abatement
technology in order to minimize capital expenditures for
end-of-pipe waste water treatment facilities.
End-of-process technology for BPCTCA involves the
application of the equivalent of biological treatment as
typified by activated sludge, trickling filters, aerated
lagoons, or anaerobic lagoons. Equalization with pH control
and oil separation may be required in order to provide
optimal as well as a uniform level of treatment. Chemical
flocculation aids, when necessary, should be added to the
clarification system in order to control suspended solids
levels.
Effluent limitations to be attained by the application of
the best available technology economically achievable are
presented in Table 2-3 for the 27 designated product/process
segments listed in Table 2-1. End-of- process treatment for
BATEA includes the addition of activated carbon systems to
biological waste treatment processes. Exemplary in-process
controls, as discussed in the later sections of this
document, are also included in this technology. It is
emphasized that the model treatment system does not preclude
the use of activated carbon or other suitable in-process
control systems within the plant. Such systems are
frequently employed for recovery of products, by-products,
and catalysts.
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The best available demonstrated control technology for new
sources includes the most exemplary process controls, as
previously enumerated, with biological waste treatment and
systems for the removal of suspended solids. New source
standards for the 27 designated product/process segments are
presented in Table 2-4.
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TABLE 2-1
Subcategories of the Organic Chemicals Manufacturing
Industry (Phase II - Significant Product-Processes)
Nonagueous Processes Subcategory
Products
BTX aromatics1
Cumene1
p-Xylene1
Process Descriptions
Fractional distillation
Alkylation of benzene with
propylene
Isomerization, crystalli-
zation and filtration of
mixed xylenes
Processes With Process Water
Contact only as Steam Diluent
Product Quench or Vent Gas
Absorbent Subcategory
Cnlorobenz ene2
Chloromethanes*
Chlorotoluene2
Diphenylaminel
Perchloroethylene2
Phthalic anhydride2
Phthalic anhydride1
Hexamethylenediamine 4
Hexamethylenediamine *
Methyl ethyl Ketone1
Tricresyl phosphate2
Adiponitrile1
Benzoic acid and1
benzaldehyde
Methyl chloride2
Maleic anhydride1
Chlorination of benzene
Chlorination of methyl chloride
and methane mixture
Chlorination of toluene
Deamination of aniline
Chlorination of chlorinated
hydrocarbons
Oxidation of naphthalene
Oxidation of o-xylene
Hydrogenation of adiponitrile
Ammonolysis of 1, 6 hexanediol
Dehydrogenation of sec-butyl-
alcohol
Condensation of cresol and
phosphorus oxychloride
Chlorination of butadiene
Catalytic oxidation of
toluene with air
Esterification of methanol
with hydrochloric acid
Oxidation of benzene
Aqueous Liquid Phase Reaction
Systems Subcategory
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Ethyl acetate1
Propyl acetate2
Propylene glycol2
Cyciohexanone oxime2
Formic acid2
Isopropanol1
Oxalic acid2
Calcium stearate1
Hexamethylenetetramine 2
Hydrazine solutions1
Isobutylene1
Sec-butyl alcohol1
Acrylonitrile1
Synthetic cresol2
Caprolactam2
p-Aminophenoll
Propylene oxide2
Pentaerythritol2
Saccharin2
Esteritication of ethyl alcohol
with acetic acid
Esterification of propyl alcohol
with acetic acid
Hydrolysis of propylene oxide
Hydroxylamine process
Hydrolysis of formaldehyde
Hydrolysis of propylene
Nitric acid oxidation of
carbohydrates
Neutralization of stearic
acid
Ammonia systhesis
Raschig process
Extraction from C± BTX
hydrocarbon mixture
Sulfonation and hydrolysis
of mixed butylenes
Ammoxidation of propylene
Methylation of phenol
DSM process
Catalytic reduction of
nitrobenzene
Chlorohydrin process
Aldehyde condensation
Synthesis from phthalic
anhydride derivatives
Batch and Semi-Continuous Processes
o-Nitroaniline1
p-Nitr oaniline *•
Ammonolysis of o-nitro-
chlorobenzene
Ammonolysis of p-nitro-
chlorobenz en e
Pentachlorophenol2
Chlorination of phenol
Fatty acids2
Hydrolysis of tall oil,
animal tallow and grease,
vegetable oils and soap stocks
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Fatty acid derivatives2
Esterification, ammination
of fatty acids
lonone and methyl-1
ionone
Methyl salicylate1
Condensation and cyclization
of Citral
Esterification of salicylic
acid with methanol
Miscellaneous batch2
chemicals
Numerous batch processes in
an organic chemical
complex
Citronelloi and Geraniol1 Citronella oil distillation
Plasticizers1 Condensation of phthalic
anhydride
Dyes and dye inter-2
mediates
Numerous batch processes
Pigments, Toners2
Diazotization and coupling
of amine, sulfuric acid
etc.
Pigments, Lakes2
Diazotization and coupling
of amine, sulfuric acid,
Citric Acid2
Napthenic acid2
Fermentation of molasses
Extraction and acidulation
of caustic sludge from
petroleum refinery
Monosodium glutamate2
Fermentation of beet sugar
molasses
Tannic acid1
Extraction of natural vege-
table matter
Vanillin2
Alkaline oxylation of spent
sulfite liquor
1
2
•Effluent limitations proposed.
Effluent limitations not proposed pending further
analysis of technical and/or economic data.
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Table 2-2
Effluent Limitations for the Best Practicable Control
Technology Currently Available (BPCTCA) Organic
Chemicals Manufacturing Industry - Phase II,
Significant Organic Products Segment
Efficient Effluent
Characteristic Limitations
kg/kkg production or
lb/1,000 Ib production
Maximum for Average of daily
any one day values for thirty
consecutive days
shall not exceed
Subcategory A - Nonaqueous Processes
BTX Aromatics (Fractional distillation)
BOD5 0.0039 0.0021
TSS~ 0.0055 0.0029
Cumene
No discharge of process waste water pollutants
p-Xylene
BOD5 0.0035 0.0019
TSS 0.0052 0.0028
Subcategory B - Processes with Process Water Contact
only as Steam Diluent, Quench or Vent Gas Absorbent
Chloromethanes
BOD5_ 0.22 0.12
TSS 0.33 0.18
Diphenylamine
BOD5 0.041 0.021
TSS~ 0.062 0.033
Phthalic Anhydride (oxidation of o-xylene)
BOD5 0.046 0.025
TSS" 0.069 0.038
10
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Table 2-2 (continued)
Hexamethylenediamine (adiponitrile process)
BOD5. 0.16 0.084
TSS 0.12 0.063
Cyanide 0.0010 0.00050
Hexamethylenediamine (hexanediol process)
BOD5_ 0.16 0.084
TSS 0.13 0.069
Cyanide 0.0011 0.00055
Methyl ethyl ketone
BOD5_ 0.16 0.082
TSS 0.16 0.082
Adiponitrile
BOD£ 1.1 0.61
TSS 1.1 0.61
Cyanide 0.0098 0.0049
Benzoic Acid & Benzaldehyde
BOD5. 1.0 0.55
TSS 0.33 0.18
Maleic Anhydride
BOD5. 4.2 2.3
TSS 0.27 0.15
Subcategory C - Aqueous Liquid
Phase Reaction Systems
Ethyl Acetate
BOD5. 0.10 0.055
TSS 0.16 0.082
Isopropanol
BOD5_ 0.27 0.15
TSS 0.29 0.16
Calcium Stearate
BOD5. 4.2 2.3
TSS 6.3 3.4
Hydrazine
BOD5. 0.37 0.20
TSS 0.37 0.20
Isobutylene
BOD5. 2.4 1.3
TSS 2.4 1.3
11
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Table 2-2 (continued)
Sec Butyl Alcohol
BOD5. 0.55 0.29
TSS 0.074 0.040
Acrylonitrile
BOD5_ 1.6 0.82
TSS 0.51 0.27
Cyanide 0.0045 0.0022
p-Aminophenol
BOD5_ 1.6 0.88
TSS 1.5 0.80
Subcategory D - Batch and Semi-Continuous Processes
o-Nitroaniline
BOD5_ 21 12
TSS 31 17
p-Nitroaniline
BOM 3.0 1.7
TSS 4.6 2.5
lonone and Methylionone
BOD5_ 1.1 0.59
TSS 1.1 0.59
Methyl Sal icy!ate
BOD5_ 0.87 0.46
TSS 0.19 0.11
Citronellol and Geraniol
BOD5. 2.2 1.3
TSS 1.2 0.63
Plasticizers
BOD5> 2.1 1.2
TSS 0.076 0.041
Total Copper 0.00065 0.00032
Tannic Acid
BOD5. 6.0 3.2
TSS 1.2 0.63
pH for all subcategories between 6.0 - 9.0.
12
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Table 2-3
Effluent Limitations for the Best Available Technology
Economically Achievable (BATEA) Organic
Chemicals Manufacturing Industry - Phase II,
Significant Organic Products Segment
Effluent Effluent
Characteristic Limitations
kg/kkg production or
lb/1000 Ib production
Maximum for Average of daily
any one day values for thirty
consecutive days
shall not exceed
Subcategory A - Nonaqueous Processes
BTX Aromatics (Fractional distillation)
COD 0.016 0.0089
BOD5. 0.0018 0.00099
TSS 0.0026 0.0015
Cumene
No discharge of process waste water pollutants
p-Xylene
COD 0.0086 0.0047
BOD5_ 0.0018 0.00093
TSS 0.0026 0.0014
Subcategory B - Processes with Process Water Contact
only as Steam Diluent, Quench or Vent Gas Absorbent
Chloromethanes
COD 0.55 0.29
BOD5. 0.11 0.059
TSS 0.17 0.086
Diphenylamine
COD 0.10 0.055
BOD5. 0.021 0.011
TSS 0.031 0.017
13
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Table 2-3 (continued)
Phthalic Anhydride (oxidation of o-xylene)
COD 0.22
BOD5_ 0.023
TSS 0.035
Hexamethy1enediamine (adiponitrile process)
COD 6.6
BOD5_ 0.039
TSS
Cyanide
0.058
0.00050
Hexamethylenediamine (hexanediol process)
COD 3.7
BOD5_ 0.043
TSS 0.062
Cyanide 0.00055
Methyl ethyl ketone
COD 0.67
BOD5_ 0.051
TSS 0.078
Adiponitrile
COD 42
BOD5_ 0.39
TSS 0.55
Cyanide 0.0049
Benzoic Acid & Benzaldehyde
COD 16
BOD5_ 0.11
TSS 0.17
Maleic Anhydride
COD
BOD5_
TSS
90
0.47
0.13
0.11
0.012
0.018
3.5
0.021
0.032
0.00025
2.0
0.023
0.033
0.00022
0.36
0.027
0.042
22
0.21
0.30
0.0024
8.5
0.059
0.086
48
0.25
0.074
Subcategory C - Aqueous Liquid
Phase Reaction Systems
Ethyl Acetate
COD
BOD5_
TSS
Isopropanol
COD
BOD5_
TSS
0.25
0.051
0.078
0.94
0.098
0.14
0.14
0.027
0.042
0.50
0.052
0.080
14
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Table 2-3 (continued)
Calcium Stearate
COD 11 5.7
BOD5_ 2.1 1.1
TSS 3.1 1.7
Hydrazine
COD 36 19
BOD5_ 1.2 0.63
TSS 1.8 0.94
Isobutylene
COD 20 11
BOD5_ 0.78 0.42
TSS 1.2 0.63
Sec Butyl Alcohol
COD 12 6.5
BOD5_ 0.062 0.034
TSS 0.038 0.020
Acrylonitrile
COD 42 22
BOD5_ 0.18 0.095
TSS 0.26 0.14
Cyanide 0.0022 0.0011
p-Aminophenol
COD 23 13
BOD5_ 0.51 0.27
TSS 0.74 0.40
Subcategory D - Batch and Semi-Continuous Processes
o-Nitroaniline
COD 50 27
BOD5_ 11 5.7
TSS 16 8.5
p-Nitroaniline
COD 25 13
BOD5. 1.6 0.82
TSS 2.3 1.2
lonone and Methylionone
COD 30 16
BOD5_ 0.36 0.20
TSS 0.55 0.30
15
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Table 2-3 (continued)
Methyl Salicylate
COD 30 16
BOD5 0.094 0.050
TSS 0.10 0.054
Citronellol and Geraniol
COD 34 16
BOD 0.39 0.21
TSS 0.59 0.32
Plasticizers
COD 27 14
BOD5 0.21 0.11
TSS" 0.038 0.021
Total Copper
Tannic Acid
COD 335 180
BOD5 0.66 0.36
TSS 0.60 0.32
pH for all subcategories between 6.0 to 9.0.
16
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Table 2-4
Standards of Performance for New Organic
Chemicals Manufacturing - Phase II,
Significant Organic Products Segment
Effluent Effluent
Characteristic Limitations
kg/kkg production or
lb/1000 Ib production
Maximum for Average of daily
any one day values for thirty
consecutive days
shall not exceed
Subcategory A - Nonaqueous Processes
BTX Aromatics (Fractional distillation)
BOD5_ 0.0032 0.0018
TSS 0.0028 0.0015
Cumene
No discharge of process waste water pollutants
p-Xylene
BOD5_ 0.0029 0.0016
TSS 0.0026 0.0015
Subcategory B - Processes with Process Water Contact
only as Steam Diluent, Quench or Vent Gas Absorbent
Chloromethanes
BOD5_ 0.18 0.098
TSS 0.16 0.089
Diphenylamine
BOD5_ 0.033 0.018
TSS 0.031 0.017
Phthalic Anhydride (oxidation of o-xylene)
BOD5_ 0.039 0.021
TSS 0.035 0.019
17
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Table 2-4 (continued)
Hexamethylenediamine (adiponitrile process)
BOD5_
TSS
Cyanide
0.13
0.059
0.0010
Hexamethylenediamine (hexanediol process)
BOD5_ 0.13
TSS 0.065
Cyanide 0.0011
Methyl ethyl ketone
BOD5. 0.12
TSS 0.078
Adiponitrile
BOD5. 0.95
TSS 0.55
Cyanide 0.0098
Benzoic Acid & Benzaldehyde
BOD5 0.87
TSS 0.16
Maleic Anhydride
BOD5_
TSS
3.5
0.14
0.069
0.032
0.00050
0.069
0.034
0.00055
0.068
0.042
0.50
0.29
0.0049
0.46
0.089
1.9
0.074
Subcategory C - Aqueous Liquid
Phase Reaction Systems
Ethyl Acetate
BOD5
TSS
Isopropanol
BOD5
TSS"
Calcium Stearate
BOD5_
TSS
Hydrazine
BOD5_
TSS
Isobutylene
BOD5
TSS"
0.087
0.078
0.22
0.15
3.5
3.1
2,1
1.8
2.0
1.2
0.046
0.042
0.12
0.08
1.9
1.7
1.1
0.94
1.1
0.63
18
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Table 2-4 (continued)
Sec Butyl Alcohol
BOD5_ 0.47 0.25
TSS 0.037 0.020
Acrylonitrile
BOD5. 1.2 0.67
TSS 0.26 0.14
Cyanide 0.0045 0.0022
p-Aminophenol
BOD5. 1.4 0.74
TSS 0.74 0.38
Subcategory D - Batch and Semi-Continuous Processes
o-Nitroaniline
BOD5_ 17 9.4
TSS 16 8.4
p-Nitroaniline
BOD5_ 2.5 1.4
TSS 2.2 1.3
lonone and Methylionone
BOD5_ 0.87 0.48
TSS 0.55 0.29
Methyl Salicylate
BOD5_ 0.71 0.39
TSS 0.10 0.055
Citronellol and Geraniol
BOD5_ 1.9 1.0
TSS 0.59 0.32
Plasticizers
BOD5^ 1.7 0.94
TSS 0.038 0.021
Total Copper 0.00065 0.00032
Tannic Acid
BOD^ 4.9 2.6
TSS 0.59 0.32
pH for all subcategories between 6.0 - 9.0.
19
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SECTION III
INTRODUCTION
Purpose and Authority
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 futher 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) to 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 best available
demonstrated control technology, processes, operating
methods, or other alternatives, including, where
practicable, a standard permitting no discharge of
pollutants.
Section 304(b) of the Act requires the Administrator to
publish, within one year of enactment of the Act,
regulations providing guidelines for effluent limitations
setting forth tne degree of effluent reduction attainable
through the application of the best practicable control
technology currently available and the degree of effluent
reduction attainable including treatment techniques, process
and procedure innovations, operation methods, and other
alternatives. The regulations proposed herein set forth
effluent limitation guidelines pursuant to Section 304(b) of
the Act for the organic chemicals industry.
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
performances for new sources within such categories.
Section 307(c) of the Act also requires the Administrator to
21
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propose pretreatment standards for new sources discharge to
publicly owned waste treatment plants. The Administrator
published, in the Federal Register of January 16, 1973 (38
F.jR. 1624) , a list of 27 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 organic
chemicals industry, which was included in the list published
January 16, 1973. This document is published under
authority of Section 304 (c) of the Act which requires that
information be made available in the form of a technical
report on alternate treatment models to implement effluent
limitation and standards of performance for new sources.
Implementation of the Act regarding fulfillment of these
requirements as outlined above was accomplished in a two
pnase effort. On April 25, 1974, the Environmental
Protection Agency published effluent limitations and
standards for 40 product/process segments (40 CFR 414).
These segments generally constitute the large volume
products and were designated the "Major Organic Products
Segment of the Organic Chemicals Point Source Category". A
technical report for Phase I effluent limitations was also
published in April 1974, (EPA 440/1-73/009) in which the
rationale and technical basis for the regulations were
presented. The data and information presented in this
document provides technical description of the 55
product/process segments investigated in the Phase II study
of the Organic Chemicals Manufacturing Industry.
Additionally the rationale and basis for effluent
limitations for the selected 29 product/processes are also
presented.
Scope of^the Study
The Organic Chemicals Industry was defined to include those
commodities listed under SIC 2865 (Cyclic Crudes and
Intermediates) and SIC 2869 (Industrial Organic Chemicals
Not Elsewhere Classified).
Tables 3-1 and 3-2 show 260 materials listed under SIC 2865
and 2869. It was noted that many specific commodities (e.g.
ethylene, adiponitrile, hydrazine, synthetic vanillin,
sodium sulfoxalate formaldehyde, etc.) are in the same list
with references to very large families of products (e.g.
synthetic organic dyes, coal tar distillates, organic
pigments, alcohols, flavors, enzymes, etc.).
These lists are developed by the United States Department of
Commerce and are oriented toward the collection of economic
22
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data related to gross production, sales, and unit costs.
They are not related to the true nature of this industry in
terms of actual plant operations, production, or
considerations associated with water pollution control. It
should also be noted that all the major producers of organic
chemicals are not included in the 286 group. Major
companies not in group 286 are covered in such diverse
classifications as petroleum refining, meat and dairy
products, and photographic and optical equipment.
The exact nature of the manufacturing operations at any
specific facility is characteristic only of that facility.
There are very few, if any, organic chemicals plants which
manufacture one product by a single process. Instead,
almost all plants are multi-product facilities where the
final mix of products shipped from each plant is unique. In
some cases, the actual number of commodities produced can be
in the thousands (such as a batch chemicals complex), while
other facilities manufacture only two or three high volume
products.
23
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Table 3-1
Chemicals Listed Under SIC Code 2865
Cyclic Intermediates, Dyes, Organic Pigments (Lakes and
Toners), and Cyclic (Coal Tar) Crudes
Acid dyes, synthetic
Acids, coal tar: derived from
coal tar distillation
Alkylated diphenylamines, mixed
Alkylated phenol, mixed
Aminoanthr aquinone
Aminoazobenzene
Aminoazotoluene
Aminophenol
Aniline
Aniline oil
Anthracene
Anthraquinone dyes
Azine dyes
Azobenzene
Azo dyes
Azoic dyes
Benzaldehyde
Benzene, product of coal tar
distillation
Benzoic acid
Benzol, product of coal tar
distillation
Biological stains
Chemical indicators
Naphthalene, chips and flakes
Chlorobenz ene
Chloronaphthalene
Chlorophenol
Chlorotoluene
Coal tar acids, derived from
coal tar distillation
Coal tar crudes, derived from
coal tar distillation
Coal tar distillates
Coal tar intermediates
Color lakes and toners
Color pigments, organic: ex-
cept animal black and bone
black
Colors, dry: lax.es, toners, or
full strength organic colors
Colors, extended (color lakes)
24
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Cosmetic dyes, synthetic
Cresols, product of coal tar
distillation
Creosote oil, product of coal tar
distillation
Cresylic acid, product of coal tar
distillation
Cyclic crudes, coal tar: product
of coal tar distillation
Cyclic intermediates
Cyclohexane
Diphenylamine
Drug dyes, synthetic
Dyes, synthetic organic
Eosine toners
Ethylbenzene
Food dyes and colors, synthetic
Hydroquinone
isocyanates
Lake red C toners
Lithol rubine lakes and toners
Maleic anhydride
Methyl violet toners
Naphtha, solvent: product of
coal tar distillation
Naphthalene, product of coal tar
distillation
Naphthol, alpha and beta
Naphtholsulfonic acids
Nitroaniline
Nitrobenzene
Nitro dyes
Nitrophenol
Nitroso dyes
Oils.: light, medium/ and heavy—
product of coal tar distillation
Orthodichlorobenzene
Paint pigments, organic
Peacock blue lake
Pentachlorophenol
Persian orange lake
Phenol
Phloxine toners
Phosphomolybdic acid lakes and
toners
25
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Table 3-1
(continued)
Phosphotungstic acid lakes and
toners
Phthalic anhydride
Phthalocyanine toners
Pigment scarlet lake
Pigments, organic: except
animal £>lack and bone black
Pitch, product of coal tar
distillation
Pulp colors, organic
Quinoline dyes
Resorcinol
Scarlet 2 R lake
Stilbene dyes
Styrene
Styrene monomer
Tar, product of coal tar dis-
tillation
Toluene, product of coal tar
distillation
Toluol, product of coal tar
distillation
Toiuidines
Toners (reduced or full strength
organic colors)
Vat dyes, synthetic
Xylene, product of coal tar
distillation
Xylol, product of coal tar
distillation
26
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Table 3-2
Chemicals Listed Under SIC Code 2869
Industrial Organic Chemicals, Not Elsewhere Classified
Accelerators, rubber processing:
cyclic and acyclic
Acetaldehyde
Acetates, except natural acetate
of clime
Acetic acid, synthetic
Acetic anhydride
Acetin
Acetone, synthetic
Acids, organic
Acrolein
Acrylonitrile
Adipic acid
Adiponitrile
Alcohol, aromatic
Alcohol, fatty: powdered
Alcohols, industrial: de-
natured (nonbeverage)
Algin products
Amines of polyhydric alcohols,
and of fatty and other acids
Amyl acetate and alcohol
Antioxidants, rubber processing:
cyclic and acyclic
Bromochloromethane
Butadiene, from alcohol
Butyl acetate, alcohol, and
propionate
Butyl ester solution of 2, 4-D
Calcium oxalate
Camphor, synthetic
Carbon bisulfide (disulfide)
Carbon tetrachloride
Casing fluids, for curing fruits,
spices, tobacco, etc.
Cellulose acetate, unplasticized
Chemical warfare gases
Chloral
Chlorinated solvents
Chloroacetic acid and metallic
salts
Chloroform
Chloropicrin
Citral
27
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Table 3-2
(continued)
Citrates
Citric acid
Citronellol
Coumarin
Cream of tartar
Cyclopropane
DDT, technical
Decahydronaphthalene
Dichlorodiflouromethane
Diethylcyclohexane (mixed isomers)
Diethylene glycol ether
Dimethyl divinyl acetylene (di-
isopropenyl acetylene)
Dimethylhydrazine, unsymmetrical
Enzymes
Esters of phthalic anhydride: and
of phosphoric, adipic, lauric,
oleic, sebacic, and stearic
acids
Esters of polyhydric alcohols
Ethanol, industrial
Ether
Ethyl acetate, synthetic
Etnyl alcohol, industrial (non-
beverage)
Ethyl butyrate
Ethyl cellulose, unplasticized
Ethyl chloride
Ethyl ether
Ethyl formate
Ethyl nitrite
Ethyl perhydrophenanthrene
Ethylene
Ethylene glycol
Ethyiene glycol ether
Ethylene glycol, inhibited
EthyJLene oxide
Ferric ammonium oxalate
Flavors and flavoring materials,
synthetic
Fluorinated hydrocarbon gases
Formaldehyde (formalin)
Formic acid and metallic salts
Freon
28
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Table 3-2
(continued)
Fuel propellants, solid organic
Fuels, high energy, organic
Gases, fluorinated hydrocarbon
Geraniol, synthetic
Glycerin, except from fats
(synthetic)
Grain alcohol, industrial
Hexamethylenediamine
H examethy1enet etramine
High purity grade chemicals,
organic: refined from
technical grades
Hydraulic fluids, synthetic base
Hydrazine
Industrial organic cyclic compounds
lonone
Isopropyl alcohol
Ketone, methyl ethyl
Ketone, methyl isobutyl
Laboratory chemicals, organic
Laurie acid esters
Lime citrate
Malononitrile, technical grade
Metallic salts of acyclic organic
chemicals
Metallic stearate
Methanol, synthetic (methyl alco-
hol)
Methyl chloride
Methyl perhydrofluorine
Methyl salicylate
Methylamine
Methylene chloride
Monochlorodifluoromethane
Monomethylparaminophenol sulfate
Monosodium glutamate
Mustard gas
Nitrous ether
Normal hexyl decalin
Nuclear fuels, organic
Oleic acid esters
Organic acids, except cyclic
Organic chemicals, acyclic
Oxalates
Oxalic acid and metallic salts
Pentaerythritol
29
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Table 3-2
(continued)
Per ciilor oe thy len e
Perfume materials, synthetic
Phosgene
Phthalates
Plasticizers, organic: cyclic
and acyclic
Polyhydric alcohols
Potassium bitartrate
Propellants for missiles, solid,
organic
Propylene
Propylene glycol
Quinuclidinol ester of benzylic
acid
Reagent grade chemicals, organic:
refined from technical grades
Rocket engine fuel, organic
Rubber processing chemicals, or-
ganic: accelerators and anti-
oxidants—cyclic and acyclic
Saccharin
Sebacic acid
Silicones
Soaps, naphthenic acid
Sodium acetate
Sodium alginate
Sodium benzoate
Sodium glutamate
Sodium pentachlorophenate
Sodium sulfoxalate formaldehyde
Solvents, organic
Sorbitol
Stearic acid esters
Stearic acid salts
Sulfonated naphthalene
Tackifiers, organic
Tannic acid
Tanning agents, synthetic organic
Tartaric acid and metallic salts
Tartrates
Tear gas
Terpineol
Tert-butylated bis (p-phenoxy-
phenyl) ether fluid
30
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Table 3-2
(continued)
Tetr a ch lor oethylene
Tetraethyl lead
Thioglycolic acid, for permanent
wave lotions
Trichloroethylene
Trichloroethylene stabilized,
degreasing
Trichlorophenoxyacetic acid
Trichlorotrifluoroethane tetrachloro-
dixluoroethane isopropyl alcohol
Tricresyl phosphate
Tridecyl alcohol
Trimethyltrithiophosphite (rocket
propellants)
Triphenyl phosphate
Urea
Vanillin, Synthetic
Vinyl acetate
31
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Methods Used for Development o£ the Effluent
Limitations and Standards of Performance
The effluent limitations guidelines and standards of
performance proposed herein were developed in the following
manner. The point-source category was first subcategorized
for the purpose of determining whether separate limitations
and standards are appropriate for different 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 subcategory 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
(including thermal) of all waste waters (including toxic
constituents and other constituents) which result in taste,
odor, and color in the receiving waterbody. The
constituents of waste waters which should be subject to
effluent limitations guidelines and standards of performance
were identified.
The full range of control and treatment technologies
existing within each subcategory was identified. This
included an identification of each distinct control and
treatment technology, including both in-plant and end-of-
pipe technologies, which are existent or capable of being
designed for each subcategory. It also included an
identification of the effluent level resulting from the
application of the treatment and control technologies, in
terms of the amount of constituents (including thermal) and
of the chemical, physical, and biological characteristics of
pollutants. The problems, limitations, and reliability of
each treatment and control technology and the required
implementation time were also identified. In addition, the
nonwater quality environmental impact (such as the effects
of the application of such technologies upon other pollution
problems, including air, solid waste, noise, and radiation)
was also identified. The energy requirements of each of the
control and treatment technologies were identified, as well
as the cost of the application of such technologies.
The information, as outlined above, was then evaluated in
order to determine what levels of technology constituted the
"best practicable control technology currently available",
"best available technology economically achievable", and the
"nest available demonstrated control technology, processes,
operating methods, or other alternatives." In identifying
such technologies, various factors were considered. These
included the total cost of application of technology in
32
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relation to the effluent reduction benefits to be achieved
from such application, the age of equipment and facilities
involved, the process employed, the engineering aspects of
the application of various types of control techniques,
process changes, nonwater quality environmental impact
(including energy requirements), and other factors.
During the initial phases of the study, an assessment was
made of the availability, adequacy, and usefulness of all
existing data sources. Data on the identity and performance
of waste water treatment systems were known to be included
in:
1. Letter surveys conducted by the Manufacturing
Chemists' Association (MCA).
2. NPDES Permit Applications.
3. Self-reporting discharge data from various states.
Limited data on process raw waste loads were also known to
be included in previous MCA survey returns.
A preliminary analysis of these data indicated an obvious
need for additional information.
NPDES permit applications data are limited to identification
of the treatment system used and reporting of final
concentrations (which were diluted with cooling waters in
many cases); consequently, operating performance could not
be determined.
Texas, where there is a high concentration of organic
chemical plants, has a self-reporting discharge system.
These reports again show only final effluent concentrations
and identify the system used; only rarely is there
production information available which would permit the
essential determination of unit waste loads.
Additional data in the following areas were therefore
required: 1) process RWL (Raw Waste Load) related to
production; 2) currently practiced or potential in-process
waste control techniques; and 3) the identity and
effectiveness of end-of-pipe treatment systems. The best
source of information was the chemical manufacturers
themselves. This additional data was obtained from direct
interviews and from inspection and sampling of organic
chemical manufacturing and waste water treatment facilities.
33
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Collection of the data necessary for development of RWL and
effluent treatment requirements within dependable confidence
limits required analysis of both production and treatment
operations. In number of cases, the plant visits were
planned so that the production operations of a single plant
could be studied in association with an end-of-process
treatment system which receives only the wastes from that
production. The RWL for such a plant and associated
treatment technology would fall within a single category.
However, the unique feedstock and product position
applicable to individual manufacturers made this idealized
situation rare.
In the majority of cases, it was necessary to visit
individual facilities where the products manufactured fell
into several subcategories. The end-of-process treatment
facilities received combined waste waters associated with
several subcategories (several products). It was necessary
to analyze separately the production (waste generating)
facilities and the effluent (waste treatment) facilities.
This required establishment of a common basis, the Raw Waste
Load (RWL), for common levels of treatment technology for
the products within a subcategory and for the translation of
treatment technology between categories.
The selection of process plants as candidates to be visited
was guided by the trial subcategorization, which was based
on anticipated differences in RWL. Process plants which
manufacture only products within one subcategory, as well as
those which cover several subcategories, were scheduled for
inspection and sampling to insure the development of a
dependable data base.
The selection of treatment plants as candidates for
visitation and sampling was developed from information
available in tne MCA survey returns. Corps of Engineers
Permit Applications, state self-reporting discharge data,
and contacts within the industry. Every effort was made to
choose facilities where meaningful information on both
treatment facilities and manufacturing processes could be
obtained.
The selection of plants visited was based upon several
factors. First, since most plants in this industry do not
have biological treatment facilities, every effort was made
to visit those plants which do have such facilities. Other
plants were selected on the basis of accessibility and
engineering judgement on the part of the contractor as to
which plants were representative of the product/processes
studied.
34
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Survey teams composed of project engineers and scientists
conducted actual plant visits. Information on the identity
and performance of waste water treatment systems were
obtained through:
1. Interviews with plant water pollution control
personnel.
2. Examination of treatment plant design and
historical operating data (flow rates and analyses
of influent and effluent).
3. Treatment plant influent and effluent sampling.
The data base obtained in this manner was then utilized by
the methodology previously described to develop recommended
effluent limitations and standards of performance for the
organic chemical industry. References utilized are included
in Section XV of this report. The data obtained during the
field data collection program are included in Supplement B.
Due to the large volume of information in Supplement B, it
was not practical to be included in this report.
A copy of Supplement B is on file at the Environmental
Protection Agency's Freedom of Information Office, 401 M
Street, S.W. Washington, D.C. and can be inspected at that
location.
Water Usage Associated with Different Segments of a
Chemical Plant
The production quantities associated with the product mix
snipped from a plant are not necessarily a true indication
of the extent or type of manufacturing activities carried
out within that plant. In many cases, several products are
produced captively within the plant and subsequently
utilized as feedstocks in the production of those products
ultimately shipped from the plant.
These factors are worthy of consideration in that the water
usage and subsequent water pollution caused by the Organic
Cnemicals industry are directly related to the specific
nature of its diverse manufacturing processes. Analysis of
these manufacturing processes is, therefore, the logical
starting point for any study whose objective is the
development of production-based effluent limitations
guidelines.
In order to develop such production-based effluent
limitations guidelines, it was necessary to utilize some
35
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"common denominator" which would relate diverse production
activities (waste generating activities) with water
pollution control technologies (waste treatment activities).
Process raw waste load (RWL) was considered as the best tool
for accomplishing this objective. Other waste water sources
of a nonprocess origin such as rain water runoff and from
utilities, laboratories, storage and transfer facilities may
also contain significant raw waste loads and require
treatment together with process waste waters. The
quantities of nonprocess waste water loads is not normally
related to the quantities of production. These nonprocess
waste waters were therefore not considered in addition to or
as part of the process raw waste loads except in certain
cases such as in batch process as noted in Section IV.
Nonprocess waste waters which are significant and require
treatment may be provided effluent allocations for such
sources under Section 402 (NPDES) for permit issuance.
For purposes of this study, the process RWL is defined as
the quantity of waste and pollutants generated by a
manufacturing process, divided by the quantity of chemical
product derived from the process. In this context, the
process represents a unique set of chemical conversions and
unit operations by which a specific feedstock is transformed
into a specific set of products, co-products, and by-
products. The quantities of water and pollutants are
measured prior to treatment for removal of pollutants.
These quantities include all water which contacts chemicals
within the process battery limits and excludes non-contact
water associated with heating and cooling surface heat
exchangers. This differentiation was drawn on the basis
that oxygen-demanding parameters (for which effluent
limitations guidelines are subsequently developed) are
associated primarily with such contact wastes. It is
appreciated that surface run-off, tank drainage, and other
sources outside the battery limits may also contribute to
this type of pollution, but very little data are available
to indicate the significance of these sources compared to
actual process wastes.
A detailed discussion of the process RWL, contact and
noncontact water usage, and the interactions of feedstocks,
products, and associated chemical conversions and unit
operations within the manufacturing plant complex is also
given in the Development Document for Phase I of this study
(EPA440/1-73/009). Phase II of the organic chemicals
industry study includes 29 additional product/process
segments for which effluent limitations and guidelines are
presently established and 26 other product/processes for
which effluent limitation and guidelines are not presently
36
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established. It is expected that limitations and guidelines
for these will be established at a later date.
Waste Water Control Technology
The development of waste water reduction factors is another
item requiring preliminary comment. It was originally
anticipated that these factors (relating to demonstrated
treatment technologies defining BPCTCA, BATEA, and BADCT)
could be obtained from performance data on many operating
treatment plants in the organic chemicals industry. It was
known that this industry did not have numerous waste water
treatment facilities; however, the original assumptions
proved to be overly optimistic. Relatively few organic
chemical manufacturers were able to provide substantial data
on the treatment of their waste water.
Information from an industry survey conducted in 1972 by
members of the Manufacturing Chemists Association which
consisted of 100 organic chemicals plants had indicated that
approximately 10 percent of the plants surveyed had
biological treatment systems installed. This was confirmed
from plant visits by the contractor and review of NPDES
permit applications. For these sources of data and
information, the following approximately describes the
industry's waste treatment practices: 80 percent of the
industry's 674 production facilities (Dept. of Commerce 1972
Census of Manufacturers) were found to provide no on-site
treatment other than neutralization of their waste water.
Many of these (approximately 50 percent) presently discharge
to municipal treatment systems. Of the remainder, ap-
proximately 10 percent provide miscellaneous physical
treatment such as sedimentation, while approximately 10
percent provide biological treatment of some type.
According to the 1967 Department of Commerce Census of
Manufacturing - Water Use (latest data available) there are
174 plants treating wastewaters. This is 26 percent of the
674 plants. Of these, 77 plants have pH control and an
estimated 40 plants have pH control only. Thus, 134 plants,
20 percent of the total, have treatment other than pH
control.
Biological treatment typified . by the activated sludge
process was defined as BPCTCA. The addition of activated
carbon with suspended solids removal by filtration was
defined as BATEA. The addition of a filtration step to the
BPCTCA activated sludge process was defined as BADCT.
Reduction factors based upon the performance of existing
biological systems, in this and other similar industries as
37
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established. It is expected that limitations and guidelines
tor these will be established at a later date.
Waste Water Control Technology
The development of waste water reduction factors is another
item requiring preliminary comment. It was originally
anticipated that these factors (relating to demonstrated
treatment technologies defining BPCTCA, BATEA, and BADCT)
could be obtained from performance data on many operating
treatment plants in the organic chemicals industry. It was
known that this industry did not have numerous waste water
treatment facilities; however, the original assumptions
proved to be overly optimistic. Relatively few organic
chemical manufacturers were able to provide substantial data
on the treatment of their waste water.
Information from an industry survey conducted in
1972 by members of the Manufacturing Chemists Association
which consisted of 100 organic chemicals plants had
indicated that approximately 10 percent of the plants
surveyed had biological treatment systems installed. This
was confirmed from plant visits by the contractor and review
of NPDES permit applications. For these sources of data and
information, the following approximately describes the
industry's waste treatment practices: 80 percent of the
industry's 674 production facilities (Dept. of Commerce 1972
Census of Manufacturers) were found to provide no on-site
treatment other than neutralization of their waste water.
Many of these (approximately 50 percent) presently discharge
to municipal treatment systems. Of the remainder, ap-
proximately 10 percent provide miscellaneous physical
treatment such as sedimentation, while approximately 10
percent provide biological treatment of some type.
According to the 1967 Department of Commerce Census of
Manufacturing - Water Use data available) the are
174 plants treating wastewaters. This is 26 percent of the
674 plants. Of these 77 plants have pH control and an
estimated 40 plants have pH control only. Thus, 134 plants,
20 percent of the total, have treatment other than pH
control.
Biological treatment typified by the activated sludge
process was defined as BPCTCA. The addition of activated
carbon with suspended solids removal by filtration was
defined as BATEA. The addition of a filtration step to the
activated sludge process was defined as BADCT.
Reduction factors based upon the performance of existing
biological systems, in this and other similar industries as
38
-------
well as in-process control, and information available in the
literature were tne bases used to develop each technology
level effluent limitation. These factors were applied to
each of the raw waste loads determined for each of the
product/process segments.
39
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-------
SECTION IV
INDUSTRY CATEGORIZATION
Discussion of the Rationale of categorization
A major goal of this effort was to broaden the RWL data base
and to further substantiate the Phase I subcategorization.
The following is a synopsis of the subcategorization
rationale which was thoroughly discussed in the Phase I
study.
The diverse range of products and manufacturing processes to
be covered suggested that separate effluent limitations be
designated for different segments within the industry. To
this end, a subcategorization of the organic chemicals
industry was developed.
Manufacturing processes have been examined for the type of
contact process water usage associated with each. Contact
process water is defined to be all water which comes in
contact with chemicals within the process and includes:
1. Water required or produced (in stoichiometric
quantities) in the chemical reaction.
2. Water used as a solvent or as an aqueous medium for
the reactions.
3. Water which enters the process with any of the
reactants or which is used as a diluent (including
steam).
4. Water associated with mechanical devices such as
steam-jet ejectors for drawing a vacuum on the
process.
5. Water used as a quench or direct-contact coolant
such as in a barometric condenser.
Noncontact flows not included in the RWL data include the
following:
1. Sanitary waste water.
2. Boiler and cooling tower blowdown or once-through
cooling water.
41
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3. Chemical regenerants from boiler feed water
preparation.
4. Storm water runoff from nonprocess plant areas,
e.g., tank farms.
The type and quantity of contact process water usage are
related to the specific unit operations and chemical
conversions within a process. The term "unit operations" is
defined to mean specific physical separations such as
distillation, solvent extraction, crystallization,
adsorption, etc. The term "chemical conversion" is defined
to mean specific reactions such as oxidation, halogenation,
neutralization, etc.
Description of Subcategories
Four process subcategories have been established and are
discussed in the following text. Subcategories A, B, and C
relate to continuous processes, while Subcategory D relates
to batch and semi-continuous processes. In the Phase I
study, subcategories A, B, and C were developed to represent
product/process segments that are continuously operated.
The following subcategories with accompanying descriptions
also apply to Phase II product/process segments.
Subcategory A; Continuous Nonaqueous Processes
This group involves minimal contact between water and
reactants or products within the process. Water is not
required as a reactant or diluent, and is not formed as a
reacrion product. The only water usage stems from periodic
wasnes of working fluids or catalyst hydration. Heating and
cooling are done indirectly or through nonaqueous
(hydrocarbon) working fluids. Process raw waste loads
should approach zero, with variations caused only by spills
or process upsets, which can be minimized by good
housexeeping, equipment maintenance and process controls.
Subcategory B: Continuous Vapor-Phase Processes Where Contact,
Water is Used Only as Diluent, Quench or Vent Gas Absorbent
In this Subcategory, process water usage is in the form of
dilution steam, a direct contact quench, or as an absorbent
for reactor effluent gases. Reactions are all vapor-*phase
and are carried out over solid catalysts. Most processes
have an absorber coupled with steam stripping of chemicals
for purification and recycle. Steam is also used for
catalyst decoking. It is feasible to reduce some process
42
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raw waste loads almost to zero through increased recycle
and/or reuse of contact water in this subcategory.
Subcateqory C; Continuous Liquid-Phase Reaction Systems
Liquid-phase reaction systems involve a catalyst in an
aqueous medium such as dissolved or emulsified mineral salt,
or acid/caustic solution. Continuous regeneration of the
catalyst system requires extensive water usage. Substantial
removal of spent catalyst and inorganic salt by-products may
also be required. The working aqueous catalyst solution is
normally corrosive. Additional water may be required for
final purification or neutralization of products.
Requirements for purging waste materials from the system
prevent process raw waste load from approaching zero.
Subcateqory D: Batch and Semi-Continous Processes
This subcategory is characterized by processes which are
carried out in reaction kettles equipped with agitators,
scrapers, reflux condensers, etc., depending on the nature
of the operation. Many reactions are liquid-phase with
aqueous catalyst systems. Reactants and products are
transferred from one piece of equipment to another by
gravity flow, pumping, or pressurization with air or inert
gas. Much of the material handling is manual, with limited
use of automatic process control. Filter presses and
centrifuges are commonly used to separate solid products
from liquid. Where drying is required, air or vacuum ovens
are used. Cleaning of noncontinuous production equipment
constitutes a major source of waste water.
Basis for Assignment to Subcategories
The subcategorization system assigns specific products to
specific subcategories according to the water usage in
manufacturing as previously defined. Where more than one
process is commercially used to produce a specific chemical,
it is possible that the chemical may be listed in more than
one subcategory since the unit operations and chemical
conversions associated with different feedstocks may differ
drastically in regard to process water usage and associated
RWL.
It is noted that the field sampling in Subcategory D for
fatty acids, dyes, pigments and plasticizers was based on
end-of-pipe sampling. Therefore, the associated RWL flow
data contains minimal amounts of noncontact waters. This is
in contrast to other products where noncontact waters were
able to be excluded.
43
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Product: BTX Aromatics
Process: Fractional Distillation
Process RWL Subcategory: A
Chemical Reactions: None
The product obtained here is a mixture consisting of
benzene, • toluene, and xylenes which are separated from
paraifinic, olefinics, and mixed high boiling aromatic
organics (over 150°C). Some ethyl benzene is also
recovered. The process involves a series of fractionating
columns. There is no direct contact water; consequently raw
waste loads are very low.
PROCESS FLOW
liters/kkg 46.7
gals/M Ibs 5.6
BOD5 RWL
mg/liter1 320
kg/kkg* 0.015
COD RWL
mg/liter1 1150
kg/kkg* 0.053
TOC RWL
mg/literi 328
kg/kkgz 0.015
i Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2 Raw waste loadings are based on unit weight of pollutant
per 1000 unit weights of product.
44
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Product; Cumene
Process; Alkylation of Benzene with Propylene
Process RWLSubcategory; A
Chemical Reactions:
HjPOj,
CH3CH - CH2
Benzene + Propylene Cumene
(I sopropy1 Benzene;
Typical Material Requirements;
1000 Kg Cumene
1000 Kg Cumene
Benzene 720 kg
Propylene 389 kg
Phosphoric Acid (SPA) 666 kg
Cumene is an intermediate in the production of phenol.
(Acetone and Acetophenone are co-products.) Cumene is also
an excellent blending ingredient of high-octane gasoline.
Although cumene is a naturally occurring chemical, present
in many crude oils, the commercial product is synthesized by
the catalytic alkylation of benzene by propylene. The
principal side reactions, depending on the catalyst system
employed, include polyalkylation to form di- and tri-
isopropyl-benzene, polymerization of a portion of the
propylene, and the production of n-propylbenzene by
isomerization.
Catalyst systems that have been used to produce cumene
include such materials as sulfuric acid, hydrofluoric acid,
boron trifluoride, silica, zinc chloride on alumina, and
others. However, the two catalyst systems most commonly
used for commercial production are aluminum chloride and
solid phosphoric acid (SPA). The catalyst system used at
the process plant visited during the field data collection
program employed the SPA catalyst.
45
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A typical .flow diagram for the solid phosphoric acid process
of producing cumene is illustrated in Figure 4-1. As shown,
this process requires a reactor and three distillation
columns - one for rejection of propane, one for the recycle
of unreacted benzene, and the third to rerun the cumene
product so as to reject a minor quantity of polyalkylated
materials (mainly diisopropylbenzene). Yields obtained by
this process are over 90% of stoichiometric values on both
benzene and olefin.
The aluminum chloride process is similar to that illustrated
for solid phosphoric acid but requires additional equipment
for the drying of recycle streams and neutralization of the
reaction products.
A mixture of propylene and propane is blended with both
fresh and recycled benzene in a raw materials feed tank.
Water (as steam condensate) at 100-150 ppm is injected into
the reaction mixture. The reaction mixture is feed to the
top of a fixed-bed reactor, where the liquid trickles down
through the catalyst bed. Steam (noncontact) is used to
preheat the reaction mixture. The process is carried out in
a continuous manner.
The reaction product (effluent from the reactor) is then
filtered. The water phase ( 1.0 liter/day) is removed to a
water drain. A depropanizer still receives the organic
phase. Propane is separated out and can be recycled to the
reactor. Waste water from the propane accumulator amounts
to about 0.3 kg/1000 kg of product.
Unreacted benzene is removed in a benzene distillation
column. The benzene is recycled with fresh benzene to the
raw materials mix or feed tank. Bottoms from the "benzene
column" contain cumene and higher alkylaromatics.
Cumene is removed as a product in the finishing still.
Diisopropylbenzene is the major by-product removed as still
bottoms.
The only continuous waste water streams are from the benzene
storage area, the waste water following the propane
accumulator ( 0.3 liter/1,000 kg of cumene produced), and
the water phase from the filter following the reactor. This
latter stream is an intermittent flow (< 1.0 liter/day).
In newer processing plants, a combination air/water cooling
system can greatly reduce the noncontact water requirement.
This is illustrated as follows:
46
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Cooling Water Circulation_Requirement
With air cooling 24,200 liters/kkg product
Without air cooling 82,600 liters/kkg product
Steam required to heat the distillation towers is 7,590 kg
per 1000 kg of product.
Process RWL based on waste water flows are indicated in the
tabulation below:
PROCESS FLOW
liters/kkg 0.334
gal/M Ibs 0.04
BOD5 RWL
mg/liter* 180
kg/kkg* 0.0001
COD RWL
mg/liter1 490
kg/kkg* 0.0003
TOC RWL
mg/liter1 180
kg/kkg* 0.0001
1 Raw waste concentrations are based on unit weight of
pollutants per unit volume of process waste waters.
2 Raw waste loadings are based on unit weight of pollutants
per 1000 unit weights of product.
The raw waste load from cumene is minimal when expressed on
a production basis. It is recommended that the process raw
waste load for the cumene process be considered as no
dishcarge since the quantity of the actual load is
insignificant.
47
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F
i«
TTTTfi?
REACTOR
1
DEPROPAN1ZER
BENZENE STRIPPER
n
CUMENE FINISHING
I
n
i
rn
Z
-<
r-
;H
O -p
Z O
Z
M
m
Z
-o
70
O
•o
CO
CO
-------
Product: p-Xylene
Process: Isomerization, Crystallization, and Filtration of
mixed Xylenes.
Process RWL Subcategory: A
Because of the rapidly increasing demand for aromatic di-
functional acids, interest in pure xylene isomers has been
growing. The C8 aromatics found in catalytic reformate
consist roughly of 45 percent m-xylene, 20 percent each o-
and p-xylene, and 15 percent ethylbenzene. There is much
less demand for m-xylene than for either of the other two
xylene isomers. An isomerization unit, which is used to
shift methyl groups, converting m- and o-xylene to
additional p-xylene, is frequently built onto existing
xylene-isomer separation facilities.
All p-xylene processes currently in operation use a
combination of crystallization and centrifugation to
separate and purify p-xylene. The crystallization step is
usually in concert with o-xylene and/or ethylbenzene removal
and isomerization.
Figure 4-2 illustrates a typical two-stage crystallization
process with an isomerization unit.
*
Crystallization processes generally have the following steps
in common, although the techniques may vary:
Feedstock drying
First-stage crystallization (to about -27°C to 32°C)
Second-stage crystallization (to about -18°C to -4°C)
Recovery and melting of crystals from first stage
Recovery and melting of crystals from second stage.
It is necessary to lower the water content in the feedstock
to about 10 ppm because water introduced into the process
will freeze and cause plugging of the centrifuges and rotary
filters. All processes utilize similar drying techniques,
which usually consist of passing the feed through alumina or
silica-gel beds. One bed is on-stream while the other bed
is being regenerated either by electric heaters or with
jacketed steam.
The major differences in the processes are the mechanics of
the crystallization and separation facilities. Most
processes use direct refrigeration. The feed is precooled
to about -40°C using propane and ethylene, and the chilled
feed is then sent to the first-stage crystallizer at an
49
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FIGURE 4-2
PARA-XYLENE, ISOMERIZATION; CRYSTALLIZATION, AND FILTRATION OF MIXED-XYLENE
MIXED Cg
AROMATICS
REFRIGERATION
SYSTEM
FIRST STAGE
CRYSTAL-
LIZER
ui
o
H2MAKF,UP
Ll
SECOND STAGE
CRYSTAL-
LIZER
ROMATICS
-------
operating temperature of -62°C to 66°C. The first-stage
crystallizers are usually scraped-surface tubular exchangers
or tank crystallizers. In each of these devices, an
agitator with spring-loaded blades is used to scrape the p-
xylene crystals from the walls.
The crystals formed in the first stage are relatively small.
Therefore, strict control of crystal size is necessary to
insure that the centrifuges or filters used in their
recovery will be of adequate size.
Considerable advances have been made in the last several
years in development of more efficient solid-liquid
separation devices. Most modern domestic plants utilize
continuous solid-bowl centrifuges in the first stage. Two
bowls rotating horizontally at different speeds cause a
helical screw motion on the outer surface of the inner bowl.
The helical motion moves the solids from the settling slurry
pool through a draining section emitting a nearly dry cake.
The centrifuges can be regulated to control bowl revolution
speeds, bowl differential, and slurry pool depth. This can
achieve p-xylene first-stage purity of 85%. The centrifuges
can be fitted for backwash, but the benefits are doubtful.
Crystals grown in the first stage tend to be long and thin
monoclinic needles that drain with difficulty. As a result,
a sizable portion of mother liquor tends to remain occluded
in the interstices between the p-xylene crystals.
Crystals from the first stage are melted (or partially
melted) and recrystallized at about -32°C. The second-stage
crystallizers are similar to the first-stage units. The
second-stage crystals tend to be cylindrical in shape,
approximately 200 X 360 microns, and drain more easily.
Furthermore, the viscosity of the mother liquor in the
second stage is about 1 cp* compared to 5 cp in the first
stage. This difference in viscosity enhances the drainage
rate. Also, a pusher-plate mechanism is available in the
second stage crystallizer to increase the drainage rate in
the exit section. About 99.5% pure p-xylene is obtained
from this type of two stage operation.
The filtrates from the first- and the second-stage liquid-
solid separation are sent to the isomerization reactor after
mixing with hydrogen gas. In the reactor, m-xylene is
isomerized over a platinum catalyst into an equilibrium
mixture of the three isomers, which is then recycled through
51
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the p-xylene crystallization steps. The isomerization
reaction is run to extinction, that is, only the para isomer
of xylene is withdrawn from the manufacturing operation.
The hydrogen gas is required to provide the hydrogen
atmosphere necessary for conducting the xylene isomerization
process and is generally produced on the site.
Consequently, the isomerization and the hydrogen facilities
are an integral part of the p-xylene process.
The major sources of waste water are the regeneration water
used during decoking of catalyst beds and the steam drum
washdown from the hydrogen plant. These streams are inter-
mittent, and the amounts are insignificant. The
monoethanolamine (MEA) contaminated waste water from the
hydrogen plant may be difficult to treat biologically. Deep
well disposal has been practiced in the past in some cases
on these wastes.
The averages of four sets of composite samples for the plant
which was surveyed are presented in the tabulation below:
PROCESS FLOW
liters/kkg 44.3
gals/M Ib 5.3
BOD5 RWL
mg/literi 238
kg/kkg * 0.01
COD RWL
mg/literi 580
kg/kkg2 0.025
TOC RWL
mg/liter1 159
kg/kkg 0.007
1. Raw waste concentrations are based on unit weight of
pollutants per unit volume of process waste waters.
2. Raw waste loadings are based on unit weight of pollutants
per 1000 unit weights of product.
The p-xylene process produces very small raw waste loads on
the basis of unit production.
52
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Product; Chlorobenzene
Process; Chlorination of Benzene
Process RWL Subcategory; B
Chemical Reaction;
C6H6 + C12 > C6H5C1 + HC1
Benzene Chlorobenzene
Chiorobenzene, an important intermediate in the manufacture
of dyes and insecticides, is manufactured by the
chlorination of benzene. Two faciilities were visited
during the field-data collection program, one which
manufactured Chlorobenzene exclusively, and one which also
produced diChlorobenzene. Figures 4-3 and 4-4 are process
flow diagrams of these two facilities, respectively.
At the first facility (Chlorobenzene only), benzene and
chlorine are fed to the reactor, and the hydrochloric acid
produced by the reaction is absorbed in water to make
aqueous hydrochloric acid. The Chlorobenzene formed by the
reaction is neutralized with sodium hydroxide and then puri-
fied by distillation. The brine formed during the
neutralization step goes to the sewer, and a tar-like
residue from the Chlorobenzene distillation is incinerated.
The second facility (chlorobenzene-dichlorobenzene) uses a
very smilar processing strategy, with a few additions. The
hydrochloric acid coming from the absorption step is
purified by carbon adsorption, and the tail gas which passes
through the absorber is scrubbed with water prior to exhaust
to the atmosphere. Another difference in the procssing
strategy at this facility is in the purification of the
Chlorobenzene reaction products. The products proceed to a
distillation column, where any unreacted benzene is taken
overhead and recycled to the chlorinator. The products
proceed from the bottom of this distillation column to a
second distillation column, where Chlorobenzene product is
taken overhead while the bottoms from the distillation
column proceed to dichlorobenzene refining.
In the survey period, waste water samples from each facility
were collected for analysis. The following is the mean
value of waste water analyses from the two plants:
53
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FIGURE 4-3
CHLOROBENZENE—CHLORINATION OF BENZENE
WATER
en
BENZENE
CHLORINE
CHLOROBENZENE
HEAVY ENDS
TO INCINERATION
-------
FIGURE 4-4
DICHLOROBENZENE—CHLORINATION OF BENZENE
»TO ATMOSPHERE
WATER
BENZENE
RECYCLE TO
CHLORINATOR
HCI
WASTEWATER
CHLOROBENZENE
TO DICHLORO-
BENZENE
REFINING
-------
PROCESS FLOW
liter/kkg
gal/1000/lb
BODji
ing/liter
kg/kkg
COD
n
J
TOC
1.
2.
mg/1
kg/kkg
mg/1
kg/kkg
50
6
300
0.015
7700
0.38
4780
0.239
Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
Raw waste loadings are based on unit weight of
pollutant per 1000 unit weights of product.
56
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Product: Cnlorinated Methanes (Methylene Dichloride,
Chloroform, and Carbon Tetrachloride)
Process; Chlorination of Methyl Chloride and Methane
Mixture
Process RWL Subcategory: B
Chemical Reactions:
-> CH^Cl + HC1
Methane
CH Cl + 2C12
Methyl Chloride
CH.C1 + 2C12
Methyl Chloride
Methyl Chloride
Methyl Hydrogen
Chloride Chloride
CH2C12 + HCl
Methylene
Dichloride r
CHC1- + 2HC1
Chloroform
'C
+ 3HC1
CH2C12 + C1
2
Methylene Dichloride
Carbon
Tetrachloride
- > CHC13 + HCl
Chloroform
CHC1
C1
i3 - v,,2
Chloroform
Typical Material Requirements:
+ HCl
Carbon
Tetrachloride
The material requirements depend upon which of the
chlorinated products is desired. In general, the chlorine
consumption is 7% beyond theoretical needs, but may be
lowered depending on the chloromethanes products mix. The
methyl chloride requirement also is approximately 1% above
theoretical needs.
Chloromethanes find their widest application as solvents.
Methylsne dichloride is used in the plastics field as a
solvent for polycarbonates, isocyanates, and cellouse
diacetate. As a urethane-foam blowing agent in Europe, it
is important as the spinning solvent for cellulose acetate.
Chloroform is used as a solvent for textile degreasing and
57
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an extractant for food flavors, steroids, and antibiotics.
Carbon tetrachloride is used as a solvent in nonflammable
cleaning agents.
In addition to their wide use as solvents, there are
numerous other applications of chloromethanes. Methylene
dichloride is used as a nonflammable paint remover, and also
in purification of steroids as a reaction medium, e.g., in
the manufacture of phosphates, insecticides, and vegetable
oil extracts. Two developments of great potential
importance are the use of methylene dichloride as a
polyurethane-foam blowing agent and in aerosal hair sprays.
Chloroform finds wide use as an intermediate in the
production of other materials. In addition, chloroform is
used in certain pharmaceutical formulations such as cough
medicines, rubbing liniments, and anesthetics.
Carbon tetrachloride is used primarily in the manufacture of
methylene chloride and chloroform. However, it is also used
as a fluid in certain fire extinguishers.
Chlorinated methanes can be produced from methane, from
methyl chloride, or from a mixture of both materials. The
reactions may be carried out by either thermal or photo
activation. The former, which requires a temperature of
approximately 700°F, is preferred commercially, because it
requires lower investment and maintenance costs, and allows
more complete conversion of chlorine.
A typical process flow diagram for producing chloromethanes
starting with a mixture of methane and methyl chloride is
shown in Figure 4-5.
The feed methane is first purified and dried in a
purification unit, and then is fed to the chlorination
reactor along with fresh and recycled methyl chloride and
chlorine gas. Following the reaction step, the chlorinated
products are quenched and absorbed in a refrigerated mixture
of recycle carbon tetrachloride and chloroform. Methane and
HCl are taken overhead from the quench column and are
absorbed in weak hydrochloric acid, which removes the HCl.
The remaining methane is then passed through a caustic
scrubber before being returned to the chlorination reactor.
The bottoms stream from the quench tower is stripped of its
light constituents. These are absorbed in water to remove
the remaining HCl, and are then neutralized with caustic
solution. This light-product stream is then passed through
a series of distillation towers from which methyl chloride,
58
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FIGURE 4-5
CHLORINATED METHANES- CHLORINATION
OF METHYLCHLORIDE AND METHANE MIXTURE
METHANE
METHANE
PURIF.
n
fWASTEWATER
METHYLCHLORIDE
CHLORINE
Ul
CHLORINATION
REACTOR
_ CO
C_3 CO
HCI ACID
«X CJ
CJ> CO
CAUSTIC SOLUTION
WASTEWATER
— CO
CO CO
WATER
CAUSTIC SOLUTION
1
.CHLOROFORM
CARBON
TETRACHLORIDE
RESIDUE
»»METHYL
CHLORIDE
METHLENE
DICHLORIDE
-------
methylene dichloride, chloroform, and carbon tetrachloride
are in turn obtained as final products for sale or recycled
back to the process as raw material or as absorbent.
The major water pollution sources of the process are the
waste streams discharged from the HCl absorber and the
caustic scrubber. Process RWL calculated from the flow
measurements and analyses of water samples obtained in the
survey period are presented in the following tabulation.
The analytical results also indicate that, in addition to
the parameters shown in the tabulation, parameters such as
pH and chloride may be at levels potentially hazardous to
biological treatment processes unless acclimated to accept
these wastes.
Plant 1
PROCESS FLOW
liter/kkg
gal/M Ib
BOD5 RWL
mg/liter1
kg/kkg2
COD RWL
mg/liter1
kg/kkg2
TOC RWL
mg/liter1
kg/kkg2
Sample
Period #1
598
72
7
0.004
113
0.07
420
0.25
Sample
Period #2
598
72
18
0.011
385
0.23
42
0.25
Plant 2
Sample
Period #1
2800
335
77
0.22
335
0.94
132
0.37
of
1 Raw waste concentrations are based on unit weight
pollutant per unit volume of process waste waters.
2 Raw waste loadings are based on unit weight of pollutant
per 1,000 unit weights of product.
The data shown for Plant 2 was selected for BPCTCA raw waste
load. These waste waters are presently neutralized and
discharged to surface waters.
60
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Product; Chlorotoluene
Process: Chlorination of Toluene
Process RWL Subcategory: B
Chemical Reaction:
C6H5CH3 * Cl2 >C6^ (CH3) Cl + HC1
Toluene Chlorine Chlorotoluene Hydrogen Chloride
A simplified process flow diagram for the manufacture of
chlorotoleune is shown in Figure 4-6. The chlorine gas is
reacted with liquid toluene in the presence of a catalyst.
The unreacted chlorine gas is removed in an absorption
tower, and sent to the muriatic acid plant for reprocessing.
The crude product mixture is then purified by passing
through a series of distillation stills. The light ends and
residues are disposed of by incineration, while the
unreacted toluene is recyled back to the reactor.
Vacuum distillation is employed in purifying the crude
product. The steam jets (with barometric condensers) used
to pull the vacuum constitute the only waste water pollution
source of the process. The process RWL calculated from flow
determinations and the analyses of the waste stream are
indicated in the tabulation below:
PROCESS FLOW
liter/kkg 121,000
gal/M Ib 14,500
BOD5 RWL
mg/liter1 2
kg/kkg* 0.24
COD RWL
mg/liter1 15
kg/kkg2 1.82
TOC RWL
mg/literi 2
kg/kkg2 0.24
* Raw waste concentrations are based on unit weight of
pollutant per unit volume of contact process waste waters.
61
-------
FIGURE 4-6
CHLOROTOLUENE - CHLORINATION OF TOLUENE
CHLORINE
REACTOR
•WATER
ABSORBER
AQUEOUS HCL TO oTr,H ,FT
MURIATIC ACID .""" JET
PLANT |
AI7
TOLUENE
RESIDUE TO
INCINERATION
STEAM JET
CONDENSATE
62
-------
2 Raw waste loadings are based on unit weight of pollutant
per thousand unit weights of product.
The only waste water from this process is the large quantity
of steam jet condensate from the vacuum still. The
contaminant concentrations in these streams are, however,
quite low. In the near future, the process will be modified
from vacuum distillation to atmospheric distillation. This
modification should substantially reduce the wastewater
volume and pollutants. At the present time, all process
waste water is discharged to the local municipal waste water
treatment plant.
63
-------
Product; Diphenylamine
Process: Deamination of aniline
Process RWL Subcategory; B
Chemical Reaction;
2 C6H5NH2
line Diphenylamine Ammonia
Diphenylamine (DPA) is used extensively in the rubber
cnemicals field, generally as a retarder, and its
derivatives are employed as antioxidants.
Production of diphenylamine may proceed by various routes;
however, the plant visited during the field survey utilized
a vapor-phase catalytic reaction involving the deamination
of aniline. A simplified process flow diagram is shown in
Figure 4-7.
As shown in the diagram, liquid aniline is pumped at a
uniform rate from storage tanks into an externally-heated
vessel which serves as preheater and vaporizer. In this
vessel, aniline is vaporized, and the vapors are heated to a
temperature of approximately 400°C to 500°C. Hot aniline
vapors pass through the catalyst chamber, which is
maintained at approximately 400°C to 550°C. The exit gases
of the DPA converter then pass into an aniline stripper, in
which aniline and other volatile constituents (such as
ammonia, small amounts of water, and other volatile by-
products) remain in the vapor state, while DPA condenses
with some aniline and is drawn off as crude DPA. The crude
product is then purified in a series of distillation
columns.
The gases leaving the aniline stripper are cooled in an
aniline condenser and a portion recycled to the aniline feed
line. The vapors (containing mostly ammonia, small amounts
of water, and other volatiles) pass to an ammonia scrubber.
64
-------
DPA
DISTILLATION
m
O 30
m rn
O
O
-n
>
-------
DPA converters will not operate indefinitely, because the
reaction causes a certain amount of decomposition of
aniline, which deposits carbonaceous residues on the
catalyst. These residues reduce the efficiency of the
catalyst, and it is necessary to regenerate periodically. As
a result, in a normal plant there is more than one DPA
converter. Some converters are on a regeneration cycle while
the remaining ones are on a production cycle. On the
average, each production cycle lasts 50 hours.
Regeneration is affected by the following procedures:
1. Steam is introduced to vaporize the aniline and
DPA.
2. Steam and air are introduced to burn the
carbonaceous impurities deposited on the catalyst
surface.
3. Steam is then introduced to purge the reactor.
4. An aniline purge is used to remove water vapor.
The off-gases resulting from the burning of tars are
exhausted, and aniline and DPA are recycled.
The major waste water source in this process is the effluent
from the ammonia scrubbing tower. The waste waters from the
catalyst regeneration process are usually disposed of by
incineration and are not included in the raw waste load
calculations. The total process RWL from flow measurements
and the analyses of the waste streams during the sampling
survey are presented in the following tabulation:
Sample Period #1 Sample Period #2
PROCESS FLOW
liter/kkg 526 526
gal/M Ib 63.0 63.0
BOD RWL
mg/liter1 220 108
xg/kkg* 0.116 0.057
COD RWL
mg/literi 550 650
kg/kkg* 0.287 0.339
TOC RWL
mg/literi 450 420
66
-------
kg/kkg 0.237 0.218
1 Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2 Raw waste loadings are based on unit weight of pollutant
per 1000 unit weights of product.
The arithmetic average of the values presented in the
foregoing tabulation are for BPCTCA.
All cooling water used during the production of
diphenylamine is indirect; tube and shell exchangers are
employed. Steam usage is 1.15 Ibs per Ib product (including
the steam employed during catalyst regeneration), and
approximately 7531 of the condensates are collected. Steam
used in the regeneration cycle is live steam, and the rest
is reboiler steam.
Diphenylamine can also be produced by catalytic liquid-phase
process in which a mixture of primary arylamine and catalyst
is mixed with reactant aniline in a stainless steel reaction
chamber. The temperature of the reaction mixture is raised
to 175°C to 450°C, and the pressure is permitted to build up
to Jceep the reaction mixture in a liquid state. During the
course of the reaction, ammonia is split and vaporized. The
ammonia vapor pressure maintains the reaction mixture in a
liquid state. After holding the reaction mixture for the
requisite time at the desired temperature and pressure, the
hot mixture is permitted to flow into a receiver. Upon
cooling the mixture to about 275°C, the catalyst is
substantially crystallized from the mixture. The crude
reaction mixture can be filtered and then purified to the
final product.
67
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Product: Perchloroethylene
Process: Chlorination of chlorinated hydrocarbons
Process RWL Subcategory; B
Chemical Reactions:
Chlorinated + cl _^ cl c = c cl
Hydrocarbons
Chlorine Perchloroethylene
Perchloroethylene is used largely in dry-cleaning and vapor
degreasing. Dry-cleaning consumes approximately 85 percent
of the total; the rest goes into general solvent services
and as intermediate for fluorocarbons.
A process flow diagram for the manufacture of
perchloroethylene is shown in Figure 4-8.
The chlorinated hydrocarbons and chlorine gas are reacted
thermally (rather than catalytically) at temperatures in the
range of 500-700°C. The reactions are highly exothermic,
and control of heat transfer is a key to smooth and
efficient reactor performance.
The reaction mechanism may be visualized in terms of an
initial, very rapid, thermally activated, free-radical
Chlorination to transient compounds having high
chlorine/carbon ratios. These transient compounds decay
quickly, primarily to the low free-energy forms. The
perchloroethylene-carbon tetrachloride mixture then shifts
toward equilibrium in the rate-controlling step.
The reactor effluent is quenched, and the gas stream leaving
the quench vessel is absorbed with recycled HCl solution in
an absorption tower. The remaining unabsorbed chlorine gas
is then dehydrated and recycled back to the reactor.
The liquid reaction product stream goes from the quench
vessel to the separator, where the aqueous stream is removed
as HCl solution. The product mixture (carbon tetrachloride
and perchloroethylene) is separated by distillation. The
perchloroethylene-carbon tetrachloride mixture is controlled
by suitable recycle and by provision of appropriate
residence time in the reactor.
68
-------
FIGURE 4-8
PERCHLOROETHYLENE-CHLORINATION OF CHLORINATED HYDROCARBONS
o
vo
CHLORINE
CHLORINATED
HYDROCARBONS
CHLORINE RECYCLE
QUENCH
VESSEL
HEAVY
ENDS
STILL
T
T
Cl
R s n D .
•—
WJTFD
Cl 2
DEHYD-
DRATOR
+ PURGE TO OTHER
SCRUBBING SYSTEM
I
1 I
H
L
HCI
ABSOR-
^
I
*
uf« T r D
nA 1 1 n
SEPARATOR
CCI,
STILL
HEAVY BY-PRODUCTS
»HCI SOLUTION
^CARBON TETRACHLORIDE
| »PERCHLORO-
ETHYLENE
STILL
HEAVY WASTE
TO LANDFILL
-------
The waste water pollution sources of this process are pump-
seal leakages and miscellaneous reactor washdowns. Process
RWL calculated from flow measurements and analyses of the
waste water streams are shown in the following tabulation.
Sample Period »1 Sample Period t2
PROCESS FLOW
liter/kkg 5,400 5,400
gal/M Ib 643 643
BOD5_ RWL
mg/liter1 84 80
kg/kkgV 0.449 0.427
COD RWL
mg/literi 357 695
kg/kkg* 1.92 3.73
TOC RWL
mg/liter» 30 31
kg/kkg* 0.164 0.169
1 Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2 Raw waste loadings are based on unit weight of pollutant
per 1000 unit weaghts of product.
An average of the foregoing values was selected for BPCTCA
RWL. The wastes from this process are currently disposed of
by deep-well injection.
An alternative method for the manufacture of
perchloroethylene is by the Detrex-SD process, in which the
feedstocks (ethylene and chlorine) enter a liquid-phase
chlorination reactor. Temperature and pressure are moder-
ate, and concentrations are carefully controlled by recycle
quantity and composition to give the desired product
distribution at optimum economics.
In the classical route, perchloroethylene is prepared from
acetylene, via trichloroethylene. The chemical reaction is
shown as follows:
70
-------
The chlorine and aceytlene are brought into contact with
each other in a reactor at a temperature of 250-300°C in the
presence of barium chloride deposited on carbon as catalyst.
The product, tetrachloroethane, is then dehydrochlorinated
in a catalytic reactor to produce trichloroethylene, which
is chlorinated at 80-90°C over a catalyst containing 0.2-
0.3X FeC13 to yield pentachloroethene. The
perchloroethylene is then obtained by the
dehydrochlorination of pentachloroethane by milk of lime at
110°C and 200 mm Hg.
71
-------
Product; Phthalic Anhydride
Process: Oxidation of o-Xylene
Process RWL Subcategory; B
Chemical Reactions;
o-xylene
(C0)20
phthalic
anhydride
3H20
Phthalic anhydride is commonly produced by either of two
methods: oxidation of o-xylene, or oxidation of
naphthalene. in the U.S., about 80% of the capacity is
still based on napthalene, although there is a definite
trend in favor of the vapor-phase oxidation of o-xylene.
This trend is based primarily on economics (o-xylene
feedstock is cheaper than naphthalene). A description of
the production of phthalic anhydride using a naphthalene
feedstock is found in the following section.
Phthalic anhydride has become one of our most important
intermediates. It is commonly used during the production of
plasticizers. The less volatile phthalates are used
principally in wire and cable coatings which are subject to
higher temperatures. Phthalic anhydride derivatives are
also used in the production of alkyl resins. These resins
are in turn used in coatings, such as latex paints,
thermosetting acrylic finishes, and epoxy coatings.
Phthalic anhydride is used directly in making a number of
dyes such as eosin, quinoline yellow, phenolphthalein, and
copper phthalocyanine. It is also used during the
production of anthraquinone and anthraquinone derivatives by
condensation (Friedel Crafts) procedures.
Production of phthalic anhydride by oxidation of o-xylene is
based on vapor-phase, fixed-bed technology. Typical.
operating conditions are 5 psig and-188°C. The process uses
a carrier supported vanadium pentoxide catalyst, which
normally lasts from 3 to 5 years. The crude product ob-
tained is 99-99.536 phthalic anhydride, with some maleic,
benzoic, and other acids.
An ortho-xylene oxidation process flow diagram is shown in
Figure 4-9. Filtered air is first compressed and preheated
in a heat exchanger. The o-xylene feedstock is also
preheated and vaporized by injection into the hot-air
72
-------
FIGURE 4-9
PHTHALIC ANHYDRIDE—OXIDATION OF O-XYLENE
OJ
O-XYLENE
STEAM
AIR
1
STEAM WATER
t_J
REACTOR
^—
1
MOLTEN
SALT
HEAT
iXCHANGER
ADDITIVES
r-
WASTE-
HEAT
BOI LER
•+STEAM
HEAT
TRANSFER
OIL
I t
S.WITCH
CONDENSER
I
03
CO
T
WATER
STACK
STORAGE
WASTEWATER
STEAM
1
r \STEAM /
^^^M 1 1" T P /
I
PRE-
TREATMENT
VESSEL
— ^
T
cc.
UJ
Q_
Q_
CC.
1 —
CO
T
ce
LU
I —
CJ)
LU
oc
ANHYDRIDE WATER
INCINEF
HEAVY ENDS TO
INCINERATION
-------
stream; unevaporated o-xylene is trapped before the stream
enters the reactor.
During the reaction step, a considerable quantity of heat is
generated. The heat is removed by molten salt circulating
on the shell side of the reactor. The molten-salt solution
is passed from the top of the reactor to a heat-exchange
system, where process steam is produced. Gases leaving the
reactor at 375°C are passed through a waste-heat boiler for
additional steam generation. Cooled gases enter a bank of
automatically controlled switch condensers.
When a condenser is on the crystallization cycle, cold
mineral oil is circulated through the coils to cool and
crystallize phthalic anhydride from the gaseous phase. When
the condenser is switched to phthalic anhydride recovery,
hot oil is circulated through the coils to remelt the crude
product. The crude product is then drawn off to an
intermediate storage tank. Residual gases from the
condensers are scrubbed to reduce the volatile organic
content. The scrubbed gas passes through a demister and is
vented to the atmosphere.
Crude product from the storage tank is then passed through a
heater and into the continuous pretreatment section.
Dissolved phthalic acid is dehydrated under a slight vacuum
to the anhydride. Additives may be introduced at this point
to remove impurities produced by polycondensation of heat-
sensitive compounds. The crude phthalic anhydride is then
pumped through a pre-cooler to a continuous distillation
section. Two columns are employed, both operating under
vacuums created by two-stage steam ejectors. Waste waters
from these ejectors are sent to an incinerator. In the
first-stage stripper column, maleic anhydride and benzoic
acid are separated as overheads. Bottoms from the first-
stage column are passed to a second-stage rectifier column.
Final product (99.99% phthalic anhydride) is withdrawn as
distillate overhead.
Since waters from stream ejectors are disposed of by
incineration, the only water pollution source of the process
is the waste stream withdrawn from the vent gas scrubber.
Process RWL calculated from the flow measurements and
analyses of water samples obtained during the survey period
are snown in the following tabulation:
PROCESS FLOW
liter/kkg 593
(gal/M Ib) 71.2
74
-------
BOD5 RWL
mg/liter* 215
kg/kkgz 0.128
COD RWL
mg/liter1 1,080
kg/kkg* 0.642
TOC RWL
mg/liter* 34
kg/kkg* 0.02
1 Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2 Raw waste loadings are based on unit weight of pollutant
per 1000 unit weights of product.
These waste loads are considered as the basis for BPCTCA.
They are combined with other wastes in this plant and
treated in a biological system prior to discharge.
75
-------
Product; Phthalic Anhydride
Process: Oxidation of Naphthalene
Process RWL Subcategory: B
Chemical Reactions;
V20r
C10H8 + ^02 > CgH^'(CO)20 + 2C02 + 2H20
Naphthalene PhthalIc Anhydride
In the United States, approximately 80* of the present
phthalic anhydride capacity is based upon the oxidation of
naphthalene. However, there is a trend toward the vapor-
phase oxidation of o-xylene, which has been discussed in the
previous section. Phthalic anhydride may be produced from
naphthalene using either a fixed or fluid catalyst bed. In
addition to process variations, the purity of the final
product is a function of the reactor type, in that maleic
anhydride is formed as a by-product in the fixed-bed reactor
but it is not formed in the fluidized-bed reactor.
During the sampling period, an installation employing a
fluidized-bed reactor was visited. The fluid catalyst
consisted of a finely powdered vanadium catalyst.
A process flow diagram for the naphthalene oxidation process
is shown in Figure 4-10. The reactor containing the
catalyst is heated to an operating temperature of
approximately 480°C. Molten naphthalene is then introduced
into the reactor and vaporized by direct contact with the
catalyst charge. The vapors become admixed immediately
because of the agitated nature of the catalyst bed. The
air-naphthalene vapor mixture passes upward through the bed,
and the naphthalene is converted to phthalic anhydride,
carbon dioxide, carbon monoxide, and water vapor. The
product gases, after leaving the dense catalyst phase, pass
through a settling zone and into a cyclone system for
removal of the catalyst. Recovery of the catalyst is
reported to be 100X; thus, make-up catalyst is not required.
Following removal of the catalyst, the product gases pass
through a condensing system. Aqueous products are then
purified, using a series of distillation columns.
76
-------
LL
PURI FICATI
STILLS
>
^
n
8S
2 m
£<-
I5
O
CO Z
C3
X> <»
CO
m
CO
m C3
-------
There are two major discharges from the phthalic anhydride
process area. The most significant of these discharges is a
gaseous waste stream vented during the reaction step. The
gas contains a high concentration of organics and is
discharged to an incinerator.
The second discharge is primarily steam vapor from a vacuum
jet in the distillation section. The stream is contaminated
with a low concentration of phthalic anhydride. This stream
is aJ.so discharged to the incinerator.
A portion of the material sent to the incinerator was
condensed and analyzed. These data were used to calculate
the RWL shown in the following tabulation:
PROCESS FLOW
liters/kkg 2,290
gal/M Ib 275
BOD5 RWL
mg/literi 46,700
kg/kkg2 107
COD RWL
Dig/liter* 125,300
kg/kkg2 287
TOC RWL
mg/liter1 52,400
kg/kkg* 120
* Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2 Raw waste loadings are based on unit weight of pollutant
per 1000 unit weights of product.
This waste loading is not discharged to any sewer but rather
burned in a liquid waste incinerator.
Since the only source of waste water is periodic process
washings, the raw waste load approaches zero. Although it
is recognized that pollutant loadings from the washings
contribute to the raw waste load, it is not possible to
obtain representative samples of the waste waters. Thus,
equipment washings have not been included in the raw waste
evaluations.
Noncontact waste waters associated with phthalic anhydride
include an involuntary blowdown from the internal tempered
water system in the crude-product condensing step. In the
78
-------
condensing step, there is a swing between the use of steam
and tempered water. During the swing, the tempered water
condenses the trapped steam and is discharged. The only
pollutants are corrosion inhibitors which are in the initial
water.
79
-------
Product; Hexamethylenediamine (HMDA)
Process: Hydrogenation of Adiponitrile (ADN)
Process RWL Subcategpry: B
Chemical ^Reactions:
NH_
NC(CH2)lfCN + /»H2
AdlponltrMe Hexamethylened famine
Hexamethylenediamine (HMDA) is used in combination with
adipic acid to form polyhexamethylene adipamide, commonly
known as nylon. The demand for HMDA is estimated to be 900
million pounds by 1975, and 1,250 million pounds by 1980.
Figure 4-11 presents a process flow diagram of
hexamethylenediamine production via the hydrogenation of
adiponitrile.
The hydrogenation of adiponitrile is carried out by
contacting hydrogen with an ammonia-solvent-ADN liquid
mixture in a fixed-bed reactor containing 8-14 mesh cobalt-
oxide catalyst at 100-250°C and 200-700 atmospheres. This
transformation is characterized by its high selectivity to
HMDA at almost complete conversion of ADN.
Fresh adiponitrile and the recycle solvent (toluene) are
mixed at 32°C before being pumped to about 4,400 psia
pressure and heated to 88°C. This stream is then mixed with
fresh and recycled hydrogen and ammonia. The gaseous
effluent is recycled, while the liquid effluent is
depressurized from the reactor to 3,000 psia and heated to
400°F. This stream goes to a separator followed by a
flasher for ammonia removal. A portion of the ammonia is
compressed and recycled to the reactor, and the remainder
proceeds to an absorber. Water is used to absorb the
ammonia, which then proceeds to an ammonia stripper. The
stripped ammonia is recycled to the reactor, while the
bottoms from the column go to the sewer.
The liquid product stream from the flasher is sent to a
toluene stripper. Overhead toluene is recycled to the
reactor, and the bottoms are recovered for further
purification.
80
-------
18
. IMINE
m era
5-
HYDROGENATION
REACTOR
I
PER
i
— 1
1 '
TRATI
1
3D
CT
CO
^
-n
ON _ m
v
I
CO
-H
— t
C=»
I —
m
rn
=o
rn
n
C~3
m
r
i
r~
TOLUENE
STRIPPER
o
rs
1
i i
= J
ER
CO
— 1
m
3= a
<>_
1
EPARATOR
~1
-n
i—
i-
CO
rn
=0
* 1
* =0
™ I- N"3 -1
33 1 ABSORBERS
1 '
NH3
1!
COLUMN
X
>
O
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J O
"71 »
i m
St
71 _-
o
o
m
Z
>
^
O
Z
>
o
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O
Z
-------
The first step in refining consists of removal of HMDA
(water azeotrope) as bottoms from the first column which is
operated at 18 psia. The overhead water-amine mixture is
discarded for fuel, and the bottoms are sent to the medium
boiler stills (concentrators) to recover HMDA. The bottoms
stream from the medium boiler column is then discharged to
the HMDA refining column. Refined HMDA is taken overhead
under vacuum.
The major water pollution sources of this process are the
bottoms from the ammonia recovery column, water withdrawn as
overhead from the medium boiler stills, and the steam jet
condensate from the HMDA refining column. Process RWL
calculated from flow data and the analyses of waste water
samples collected in the survey period are presented in the
following tabulation.
Plant 1 Plant 2
Sampling Period Sampling Period
11 #2 JLL 12 £3
PROCESS FLOW
liter/kkg 1,695 1,695 1,010 ' 1,010 1,010
gal/M Ibs 203 203 121 121 121
BOD5> RWL
mg/literi 58,850 12,800 5,500 4,500 1,800
kg/kkg2 99.8 21.7 5.55 4.54 1.82
COD RWL
mg/literi 71,850 62,400 20,200 22,200 20,300
kg/kkg* 122 106 20.4 22.4 20.5
TOC RWL
mg/literi 17,800 31,400 4,600 5,700 5,000
kg/kkg* 30.2 53.2 4.65 5.76 5.05
1 Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2 Raw waste loadings are based on unit weight of pollutant
per 1000 unit weights of product.
The data shown in the above tabulation reveal that there are
significant differences in RWL from the plants surveyed.
There are three major reasons for these differences. Plant
2 partially recycles the bottoms from the ammonia recovery
column to the HMDA refining section and incinerates all the
light-end organic wastes from the refining portion of the
82
-------
operation. Plant 1 is equipped with a stack which uses
water to quench the unabsorbed vapors.
An average value from the data collected at Plant 2 was
derived. It is noted that the process wastes from both
Plant 1 and Plant 2 are currently disposed of by deep-well
injection.
The following paragraphs describe the pretreatment system
used at Plant 2. It should be noted that this system also
handles wastes from adiponitrile manufacture.
Aqueous waste from the hexamethylene diamine (HMDA) process
is fed along with by-product brine from other plant
operations into a settling tank; HMDA-waste comprises less
than 10% of the total flow. Sludge which settles out is
pumped to a pit for further settling, while the main stream
goes through primary filtration in precoated, horizontal,
leaf filters. After a second filtration, the waste stream
is pumped into injection wells for disposal. Backwash from
both filtration steps is pumped to the sludge pits.
The primary purpose of the waste treatment area is to remove
all solids which might cause plugging of the injection
wells.
Noncontact cooling water usage for both plants is tabulated
below:
Plant 1 - 453,000 liters/kkg of product
Plant 2 - 31,500 liters/kkg of product
HMDA can also be produced by the ammonolysis of 1,6
hexanediol, a process which will be described in the
following sub-section.
83
-------
Product: Hexamethylenediamine (HMDA)
Process: Ammonolysis of 1,6 - Hexanediol
Process RWL Subcategory: B
Chemical Reaction:
H.
HO(CH2)6OH * 2 NH3 > H2N(CH2)6NH2 + 2 H20
Hexanediol Hexamethylenediamine
A typical process flow diagram of hexamethylenediamine
production via the ammonolysis of 1,6 - Hexanediol is shown
in Figure 4-12.
The ammonolysis reactor is a flooded, fixed-bed, catalytic
reactor. The fresh and recycled hydrogen and liquid ammonia
are pumped to the reactor at a pressure of 3,000 psig. The
liquid ammonia is preheated to a temperature of 180 - 220°C
and fed to the reactor bottom. At this temperature, the
ammonia is above its critical temperature (132°C). The
organic feed stream, consisting of recycle
hexamethyleneimine (HMI) (30 wt X) plus fresh and recycle
hexanediol is also pumped as a liquid into the reactor. By
means of two heat exchangers (one a product-feed exchanger,
and the second a preheater), the organic liquid phase is
raised to the reaction temperature of 180 - 220°C. Positive
displacement pumps are necessary to transfer both the liquid
NH^ and the liquid organic feed at the 3,000-psig pressure
level.
Within the reactor, the liquid organic phase floods the
fixed-bed catalyst, and the liquid product stream overflows
through a discharge line at the top of the bed. Both E2 and
NH3 enter the bottom of the fixed bed as gases, but because
of the high pressure and the solvent action of the HMI, the
NH3 gas is absorbed in the HMI and subsequently reacts in
the liquid phase with the 1,6-hexanediol to produce HMDA.
Since the concentration of HMI in the liquid phase is
already at its equilibrium value, further conversion of the
diol and NH3 to the imine is negligible. A reflux condenser
is situated at the top of the reactor and the liquid
condensate is returned to the top of the fixed bed. The
vapor stream leaving this condenser is used to pre-cool the
hydrogen gas prior to recycle to the compressor, and to
condense NH3 vapor carryover from the reactor. This ammonia
condensate is returned to the reactor ammonia feed.
84
-------
FIGURE 4-12
HEXAMETHYLENEDIAMINE- AMMONOLYSIS OF 1,6-HEXANEDIOL
HYDROGEN
oo
Ul
H2 RECYCLE
COMPRESSOR
AMMONIA-
I ,6 HEXANEDIOL
HMI RECYCLE
STEAM
JETS
WASTEWATER
HEAVY ENDS TO
INCINERATION
-------
Catalysts suitable for the ammonolysis step include Raney
cobalt, Raney nickel, reduced copper, Raney copper, and
nickel on kieselguhr. The preferred catalyst is pelletized
Raney nickel. At reaction conditions, an ammonia feed
stream of 19 moles NH3 per mole of diol (2.73 kg NH3/kg
diol) and a hydrogen supply of 0.125 moles H2 per mole of
NH3 (0.0147 kg H2/kg NH3) have been found to give high
yields. A yield of 93 mole X HMDA on a diol-reacted basis
is practical, and conversions of 70 mole % per reactor pass
are used for design. A residence time of 1 hour is typical.
The liquid reactor product consisting of HMDA, HMI,
dissolved NH3 and H2, unreacted diol, by-product H2_O, and
high boilers is heat exchanged with the incoming HMI-diol
feed stream and then fed to a series of three flash drums.
The flashing operation provides a stagewise reduction in
pressure and recovers the dissolved hydrogen as a vapor for
refeeding to the compressor. A small portion of the
dissolved NH3 is also vaporized, and this is recovered in
the knockout drums of the compressor facility. The major
part of the dissolved ammonia is recovered in the ammonia
stripper column. Ammonia is liquefied overhead by a water-
cooled condenser, from which it is pumped back to the NH3
feed tank.
The ammonia stripper column operates at about 200 psig, to
condense the ammonia overhead at 55°C. The bottoms
temperature averages about 200°C. The bottoms product
(containing HMDA, HMI, diol, H20 and high boilers) is fed to
a drying column and then to the water stripper column. The
water stripper operates as an azeotropic column using
cyclohexane as the entraining agent to promote water
separation. The use of cyclohexane counteracts the
formation of the H20/HMI azeotrope. (This azeotrope has
been reported as a means of separating the HMI from the
HMDA.) The overhead stream from this tower consists of a
heterogeneous cyclohexane-water azeotrope, which condenses
as a two-phase liquid in the overhead decanter. The
cyclohexane upper layer is returned to the column as a
reflux, and the lower layer, mostly water, is sent to waste.
This column normally operates at atmospheric pressure, with
an overhead temperature of about 74°C and a bottoms
temperature of 100°C - 107°C.
The bottoms from this tower, essentially anhydrous, are fed
to tne HMI stripper column to remove HMI for recycling.
This stripper column is operated under a vacuum of about 200
mm Hg. such that reboiler temperatures in the range of 310-
330°F are not exceeded. Temperatures of 390°F and higher
tend to promote reactions between the HMDA and the unreacted
86
-------
diol to produce high boilers. The HMI stripper bottoms are
then fed to the HMDA product column, where the HMDA is taken
overhead at 99.9456 purity. The bottoms, consisting of a
small percentage of HMDA and the unreacted diol plus high
boilers, are recycled to the diol feed tank. Periodic
buildup of. the high-boiler concentration will necessitate an
intermittent purge of the bottoms. Alternatively, a 1,6-
hexanediol polishing still may be added to provide for
continuous separation of the diol from the high boilers. In
actual operation, the reactor conditions may possibly be
adjusted so that the high-boiler content is minimized to
some equilibrium value.
The major waste water pollution sources for this process are
waste waters from the drying column, the decanter associated
with the azeotropic column, and the steam jet condensate.
The analytical results obtained from the sampling survey are
shown in the following tabulation.
PROCESS FLOW
liter/kkg 1,100
gal/M Ib 132
BOD5 RWL
mg/liter1 3,630
kg/kkg* 4.0
COD RWL
mg/liter* 10,600
kg/kkgz 11.7
TOC RWL
ing/liter* 2,260
kg/kkgz 2.5
1 Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2 Raw waste loadings are based on unit weight of pollutant
per 1000 unit weights of product.
It is noted that most of the waste water upon which the
previous RWL calculations are based is currently disposed of
via deep-well injection. Only wastes such as slab washdown
water and storm runoff are treated in an aerated lagoon.
87
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Product: Methyl Ethyl Ketone (MEK)
Process: Dehydrogenation of Secondary Butyl Alcohol (SBOH)
Process RWL Subcategorv; B
Chemical Reactions:
CH3CH(OH)CH2CH3 — * CH3COCH2CH3 + H2
Sec-butyl Alcohol methyl ethyl ketone
A flow diagram for this process is shown in Figure 4-13.
Methyl ethyl ketone (MEK) is obtained by the dehydrogenation
of secondary butyl alcohol in a process analogous to the
production of acetone from isopropyl alcohol.
Preheated vapors of secondary butyl alcohol are passed
through a reactor, containing a catalytic bed of zinc oxide
or brass (zinc copper alloy) maintained at 400 to 550°C.
The reaction takes place at atmospheric pressure.
The reaction gases are condensed by passage through a brine-
cooled condenser. The uncondensed gas may be scrubbed with
water or a nonaqueous solvent to remove any entrained ketone
or alcohol from the hydrogen-containing gas.
The condensed product is run into a distillation column and
fractionated. The main fraction (methyl ethyl ketone),
boiling between 78°C and 81°C, is obtained in an 85 to 90
percent yield based on the weight of secondary butyl alcohol
charged.
The following tabulation summarizes the raw waste load data
obtained from the two plants sampled. The RWL shown for
Plant 2 is much higher because some of the light
hydrocarbons purged (used elsewhere or burned) in Plant 1
are discharged in the waste water from Plant 2.
Plant 1 Plant 2
PROCESS FLOW
liters/kkg 1,310 795
gal/M Ib 157 95
BODS RWL
88
-------
FIGURE 4-13
METHYL ETHYL KETONE (MEKj-DEHYDROGENATION OF SEC-BUTYL ALCOHOL (SBOH.
SEC-BUTYL
ALCOHOL
PREHEATER
REACTOR
co
SOLVENT
CONDENSER
-^HYDROGEN
0£
CJ
\
METHYL
ETHYL
KETONE
ALCOHOL
TO RECOVERY
-------
mg/literl
kg/kkg2
COD RWL
mg/ liter1
kg/kkg2
TOG RWL
mg/liter1
kg/kkg 2
3,000
3.
1,627
2.
521
0.
92
13
68
91,000
72.1
260,000
206
102,000
80.9
i Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2 Raw waste loadings are based on unit weight of pollutants
per 1000 unit weights of product.
The RWL from Plant 1 was chosen as BPCTCA basis.
90
-------
Product:: Trier esyl Phosphate (TCP)
Process: Condensation of Cresol and Phosphorus Oxychloride
Process RWL Subcategory: B
Chemical Reaction:
(C6Hj,(CH3)0)3PO + 3HC1
cresol (mixture of o-, phosphorus trlcresyl
m-, and p-!somers) oxychloride phosphate
TCP has the property of reducing the flammability of films.
This property has led to its use as a plasticizer for
nitrocellulose and vinyl chloride plastics. This
flammability-reducing property qualifies it for use as an
additive in hydraulic fluids and lubricants. TCP is also
used as a gasoline additive.
Figure 4-14 presents a simplified process flow diagram of
trieresyl phosphate production. Basically, the processing
involves purification and then condensation of the raw
materials, preliminary purification, and final purification
of the product.
Cresol supply has been a problem to manufacturers of
tricresyl phosphate for a number of years, both as to
availability and quality. Until the post-war period, almost
all cresol for tricresyl phosphate manufacture was derived
from coal tar acids. Most recently, improved processing of
carbolate liquids from petroleum sources has resulted in
cresols essentially equivalent to those produced from coal
tar acids. Furthermore, the shortage of cresols which has
long plagued tricresyl phosphate producers and which,
probably more than any other factor, had led to
commercialization of cresyl diphenyl phosphate in the post-
war period, appears to have been eliminated. Since the
ortho form of tri-cresyl phosphate is considerably more
toxic than those derived from m- and p-cresols, the cresol
used for the production of plasticizer grade tricresyl
phosphate is primarily a mixture of m- and p-cresol.
Although the xylenol content may be allowed to reach as high
as 30 or 4OX, the o-cresol content is held below 3X.
Because of the random distribution of the three isomers in
the resulting phosphate ester, the tri o-cresyl phosphate
content of the product is quite low. The cresols used for
91
-------
C-3
DISTILLATION
COLUMN
STRIPPING
COLUMN
T
3> 3;
11
CO —| 30
rn 30
CO •= 3D "II
— i o <= — < 1 1
1-co m
i
rn
CO
ESTER
n r r 11 y n
n t r N Nu
COLUMN
r
I 4
n CD m
3C 3D m
^ O C~3
m x — l
z m «=
CO _| 3D
=o — a»
c? ^
a
=C co
f •»• — i
f —t m
csi m »
i i i
—i
rn
«-i
r
CO OO |T1
3E ^O m
rn ~&
=o — ^
C'J 3E
m
CO
TO —
m O
O I 2
is 2
O ' m
TO n ^
O O t
^ D
o 5
5 CO
o z
o o
m ~"
-------
production of tricresyl phosphate for addition to gasoline
may contain a slightly higher o-cresol content and a higher
percentage of xylenols,
Cresols react rather readily with phosphorus oxychloride at
a temperature of approximately 100°C to form a mixture of
aryl and diaryl phosphoryl chlorides, with only small
amounts of triaryl phosphate. The diaryl phosphoryl
chloride being the least reactive, more drastic conditions
are required to obtain complete reaction. The presence of
significant quantities of aryl phosphoryl chlorides not only
reduces yield but leads to difficulty in subsequent refining
operations. Therefore, the condensation of cresol and the
oxychloride is carried out at elevated temperatures (150°C
to 300°C) depending upon the catalyst, and purification
schemes employed. A slight excess of cresol favors complete
esterification. The time required for the condensation will
vary with the catalyst and temperature of reaction. Loss of
oxychloride in the hydrogen chloride off-gas is minimized by
operating under moderate pressure and/or venting through a
condenser. Many catalysts have been reported, but the metal
halides appear to be preferred, because they permit
condensation times of 6-9 hours at temperatures of
approximately 200°C. Because the reaction mixture is highly
corrosive, glass-lined or alloy kettles are used. The
condensation reaction may be operated continuously, by
permitting the reaction mixture to pass through a series of
reactors at successively higher temperatures.
The purification techniques employed appear to have become
rather well standardized. Variation lies rather in the
oequence of application, the use of classical batch washing
in lieu of the use of columns, and the extent of
purification required for product end-use. Preliminary
purification may involve direct flash distillation of the
crude reaction mixture. The crude reaction product may be
first be washed with dilute caustic to neutralize any
hydrogen chloride and to hydrolyze and extract traces of
partial esterification products and unreacted cresylic
compounds. The addition of lime to the reaction mixture
prior to distillation, to minimize corrosion, has been
reported. Final purification of plasticizer grade products
employs wasning with dilute caustic and water (to remove
traces of organic acidity), treatment with dilute
permanganate solution (to improve color and oxidation
stability of the product, a widely accepted quality factor) ,
dehydration by heating under reduced pressure, bleaching
with activated carbon and finally filtration. The use of an
ampnoteric metal in conjunction with an alkaline wash has
also been claimed as a color-improvement refining step. In
93
-------
production of tricresyl phosphate as a gasoline additive,
some or all of the final purification steps may be omitted;
low acidity is required, but color and oxidation stability
are not critical.
As indicated in the process flow diagram, each step of the
process is performed under vacuum conditions, and each step
is equipped with steam jets and barometric condensers. The
major pollution sources are the waste streams from these
barometric condensers. The analytical results from the
sampling program are presented in the following tabulation.
PROCESS FLOW
liter/kkg 28,000
gal/M Ibs 3,355
BOD
mg/literl 40
kg/kkg* 1.12
COD
mg/literi 408
kg/kkg* 11.4
TOG
mg/literi 70
kg/kkg2 1.96
1 Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2 Raw waste loadings are based on unit weight of pollutant
per one thousand unit weights of product.
By using surface condensers it is possible to substantially
reduce the process flow requirements. Noncontact waste
waters include cooling water flows and steam condensate; the
cooling water usage is approximately 740 kg per kkg of
product, while condensate flow to the sewer is at the rate
of 0.96 kg per kkg of product.
The process RWL shown above are considered for BPCTCA
determination. All wastes from the plant are currently
discharged to the municipal sewer system.
94
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Product; Adiponitrile
Process: Chlor ination of Butadiene
Process RWL Subcategory: B
Chemical Reactions
CH2CH CH CH2 + C12 - > Mixture of fsomeric dichlorobutenes
Butadiene + Chlorine
NCCH2CH = CH CH2CN - * - > NC
Dicyanobutene Adiponitrile
Adiponitrile (ADN) is commonly used during the manufacture
of hexamethylene diamine (HMDA) . H.examethylene diamine is
in turn used as a raw material during the production of
Nylon 6/6.
A schematic flow diagram of the process is given in Figure
4-15, and the general process information is described in
the following paragraphs:
The first step in the manufacture of ADN via butadiene is
tne vapor-phase chlorination of butadiene. The reaction is
carried out at 250°C and at pressures slightly above
atmospheric. The inlet section of the reactor is designed
to insure complete and rapid mixing of the reactants, and
the rest of the vessel constructed to guarantee plug-flow
conditions, which favor the high degree of chlorine
conversion desired. By-product formation is minimized if
the molar ratio of butadiene to chlorine is kept around 6.5
to 1 and if the vapor phase is diluted with nitrogen gas to
keep a 10# (volume) of inerts in the reactor feed stream.
The ratio of fresh to recycle butadiene is approximately 0.2
to 1. When the chlorine conversion is close to 10056, the
molar yield of chlorine to chlorinated butenes is 95%. The
relative amount of the 1,4 and 3,4 dichlorobutene isomers is
of no importance since in subsequent reaction steps both
isomers are converted to the same final product. The
composition of the chlorinated butenes is as follows: 93.4
wt % dichlorobutenes, 1.6 wt % low boilers and 4.9 wt % high
boilers. The vapor-phase reaction is carried out in an
empty reactor. The reactants enter at 120°C and are heated
up to the reaction temperature (250°c) by the heat evolved
during the reaction, which is 39 kilocalories per mole.
95
-------
FIGURE 4-15
ADIPONITRILE-CHLORINATION OF BUTADIENE
AQ. CAUSTIC
BUTADIENE
CHLORINE
IOPANE J,
PROCESS
COMPRES-
SION
UJ-,
^DICHLOROBUTENE
HHANUFACTURE
L
1 1 1
_ i --» r
NaCN I
/ENT SCRUBBERS
IT CONDENSATE
IUSTIC SCRUBBER
^
HC1
^WASTES
S
DICYANO-
BUTENE
MANUFACTURE
J It
ATER 1 »
1 »4I
WASTE
STORAGE
HYBROGEN
CATALYST
kBRINE
* \ ET CONDENSATE
HCN VENT SCRUBBEF
' VFNT
WASTEWATER
DIPQNITR1LE
JET CONDENSATE 1WASTE-
R/WATER
^PROCESS SCRUBBEF
BOILER
FUEL
BOILER
FUEL
-------
The effluent stream from the reactor is cooled down to room
temperature, and condensed. The unreacted butadiene is
separated from the liquid phase, which contains the
chlorinated products, and recycled back to the reactor. The
liquid phase is sent to the cyanization section of the
plant. This liquid is composed of a mixture of
dichlorobutenes, chlorobutenes, chlorinated butanes, and
heavy materials such as tar and polymeric compounds.
The cyanization reaction is carried out in the liquid phase
at 100°C and under atmospheric pressure in the presence of
an inert gas such as nitrogen. The reaction is catalyzed by
an aqueous mixture of cuprous chloride, copper powder, and
cuprous cyanide. The molar ratio of hydrogen cyanide to
dichlorobutenes is close to 2.3 to 1. The composition of
the liquid feed to the reactor is given below on a weight
percent basis.
cuprous cyanide 0.93
calcium carbonate 15.6
water 54.6
hydrogen cyanide 9.6
dichlorobutenes 19.5
The reaction time to achieve a 92.5 mole % conversion to
1,4-dicyanobutenes is approximately 40 minutes.
The next steps in the production of ADN are the
isomerization and purification of the cyanobutenes. The
purpose of isomerization is the conversion of some of the
1,4-dicyanobutene-2 to its isomer, 1,4-dicyanobutene-1. The
purpose of purification is to render the crude dicyanobutene
mixture non-corrosive.
The liquid reaction product stream leaving the cyanization
reactor is cooled to 25°C. The cyanobutenes and organic by-
products are extracted with benzene and diluted until the
benzene concentration is approximately 66X by weight. This
organic mixture is sent to an agitated tank where the
temperature is raised to 60°C and the pH adjusted with 10%
sodium hydroxide to 11.5. The two liquid phases that result
are separated in a liquid-liquid separator; the aqueous
phase is sent to the waste treatment plant, while the
organic phase, after being heated to 70°C, is sent to
another agitated tank where more (10SS) sodium hydroxide is
added until its weight percent in the second aqueous phase
formed is around 15. These two liquid phases are agitated
vigorously in the tank which has an average residence time
of 25 minutes. The two-phase effluent stream is sent to a
decanter where the organic and aqueous phases are separated.
97
-------
This second aqueous phase is also sent to the waste
treatment tank and the organic phase (containing the
isomeric mixture of 1,4-cyanobutenes) is sent to the
adiponitrile plant.
The benzene-cyanobutene mixture is then diluted with benzene
until the cyanobutene concentration is 20% by weight, and
then fed to the hydrogenation reactor. This reaction vessel
contains a packed bed of activated charcoal promoted with 2%
(by weight) palladium. The hydrogenation reaction is
carried out under a hydrogen pressure of 400 psig at a
temperature between 100 and 120°C. The hydrogen is bubbled
concurrently with the liquid at a ratio of 35 moles of
hydrogen per mole of dicyanobutene. The liquid space
velocity in the reactor is approximately 0.4 reactor volumes
of liquid per hour per volume of catalyst. The molar
conversion of cyanobutene is 95%, with a selectivity to
adiponitrile of 99X. Since the reaction is quite
exothermic, the reactor must be equipped with an efficient
heat removal system. For example, the reaction is carried
out inside of tubes packed with catalyst while cooling water
runs through shell side of the reactor. The catalyst has an
active life of about 500 hours. It can be easily
regenerated by passing hydrogen at 500°C over the catalyst
until no more sulfur is evolved from the reactor tubes.
The reactor effluent is cooled down to room temperature and
the hydrogen separated from the liquid organic phase,
recycled water and vacuum jet condensates. The latter two
waste streams are typical of a Subcategory B vapor-phase
manufacturing operation. Process raw waste loads calculated
from flow measurements and analyses of these streams are
shown in the following tabulation:
Sample
Period f1
Sample
Period t2
Adiponitrile
Sample
Period #3
Average
PROCESS FLOW
liter/kkg 9766 9766
(gal/M Ib) 1170 1170
BOD5 RWL
ing/liter* 1250 2850
kg/kkg2 12.2 27.8
9766
1170
1800
17.6
9766
1170
1970
19.2
98
-------
COD RWL
mg/literi 15,000 14,400 12,000 . 13,800
kg/kkgz 146 141 118 135
TOC RWL
ing/liter* 4600 4500 4450 4500
kg/kkg* 44.9 43.8 43.4 44.0
1 Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2 Raw waste loadings are based on unit weight of pollutant
per 1000 unit weights of product.
The analytical results (shown in Section V) indicate that
the pollutants in the waste waters (such as ammonia
nitrogen, sulfate, cyanide, chloride, and copper) are at
levels which may be potentially hazardous to biological
treatment processes. It should be noted that although
biological treatment was chosen as the model treatment
system most generally applicable for BPCTCA, several of the
process plants surveyed currently utilize other means of
disposal, such as deep-well injection. This was the case
with the adiponitrile plant sampled. The raw waste loads
shown previously are all treated by filtration prior to
disposal by deep-well injection. In this regard, it should
be noted that the adiponitrile plant also sampled noncontact
cooling water on a once-through basis. The volume of
cooling water amounts to 424,000 liters/kkg of adiponitrile.
When it becomes necessary to treat the wastes from this
adiponitrile plant in a biological system, a multi-stage
biological system combined with in-plant controls to lessen
the discharge of inhibitory compounds may be required.
99
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Product: Benzole Acid and Benzaldehyde
Process: Catalytic Oxidation of Toluene with Air
Process RWL Sujbcategory; B
Chemical Reactions:
2C6H5CH3 + 302
Tol uene
•Toluene
2C6H5COOH + 2H20
Benzoic acid
CgH5CHO + H20
Benzaldehyde
A simplified flow diagram for this oxidation process is
shown in Figure 4-16. Toluene and air, with a mixture of
recycle gas and toluene, are combined in the reactor.
Reaction temperatures may range from 150°C to 500°C, with a
corresponding pressure range of 10 to 1 atmospheres.
Specific manufacturers operate at different conditions.
Depending upon the operating conditions, the material in the
reactor may be in the liquid or vapor phase. Reaction
conditions may be varied to give different selectivities to
benzole acid or benzaldehyde. The process RWL's have been
calculated on the basis of the total production of benzole
acid and benzaldehyde during the sampling period.
The catalysts most frequently used consist of oxides of
metals belonging to the fifth or sixth groups of the
periodic table. A mixture of uranium (93 percent) and
molybdenum oxides (7 percent), impregnated on a pumice or
asbestos carrier, is claimed to give relatively high yields
of benzaldehyde with low percentages of toluene loss via
complete combustion. The addition of small amounts of
copper oxide to the catalyst mixture reduces by- product
maleic anhydride formation. A cobalt acetate catalyst in
aqueous solution has also been used successfully.
As shown in Figure 4-16, the reactor effluent is sent to a
decant tank. A three-phase mixture of gas, organic liquid,
and aqueous liquid usually exists in this vessel. The gas
100
-------
FIGURE 4-16
BENZOIC ACID AND BENZALDEHYDE
TOLUENE
RECYCLE TOLUENE
WATER OF
REACTION
.FRESH NaOH
SOLUTION
RECYCLE
NaOH
SOLUTION
SCRUBBER
RECYCLE
TANK
SPENT
SCRUBBER
SOLUTION
AQUEOUS
NaC03
SOLUTION
AQUEOUS
DRAIN
L
CO-PRODUCT
BENZALDEHYDE
FRESH NaOH
SOLUTION
•STILL BOTTOM
RESIDUE AND WASH
TO SEWER
RECYCLE
NaOH
SOLUTION
SCRUBBER
RECYCLE
TANK
SPENT
SCRUBBER
PRODUCT SOLUTION
BENZOIC
ACID
-^RECYCLE
TO PROCESS
TAR
-------
(mainly inert nitrogen) is vented under pressure control,
with a portion recycled to the reactor to maintain proper
dilution. The aqueous liquid phase (containing water of
reaction) is decanted off using an interfacial level
controller. The aqueous layer is discharged to waste
treatment.
The organic layer is sent to the toluene stripper, where
toluene is taken overhead and recycled to the reactor, which
normally operates at 30-35% toluene conversion per pass.
The bottoms from the main stripper are crude benzoic acid
and by-products such as maleic anhydride, anthraquinone, and
complex high-boiling aromatics of unknown composition. The
crude acid is sent to the product (benzoic acid)
purification section of the process.
A side-stream containing some benzaldehyde is washed with an
aqueous solution of sodium carbonate in a wash tank. This
step is necessary to, neutralize organic acid by-products
(and some benzoic acid) present with the benzaldehyde. The
aqueous layer from the wash tank is drained and discharged.
The organic layer from the wash tank is sent to the
benzaldehyde still, where purified benzaldehyde is taken
overhead. The benzaldehyde still operates under vacuum
drawn by a vacuum pump. Seal water from the pump is
continuously discharged. An organic residue, which must be
removed periodically by water washing, forms in the bottom
of the benzaldehyde still. This material is also
discharged. The benzoic acid purification section consists
of two rectifying columns and a batch tar stripper. Each of
these distillation columns operates under vacuum drawn by
steam jet ejectors. The steam is not condensed, but rather
is discharged directly into the atmosphere. Consequently,
this steam was not considered in the process RWL
calculations. Jt be noted that the gases drawn into the
jets are scrubbed; and little carryover of organic matter is
anticipated.
The crude benzoic acid from the main strippers is sent to
the middles column, where partially rectified benzoic acid
is drawn off as bottoms. The overhead gases are drawn by
vacuum through the middles column scrubber, where they are
scrubbed with an aqueous caustic solution prior to discharge
through the steam jets. The caustic solution is recycled by
means of the scrubber recycle tank; fresh caustic is added
periodically to the circulating solution, with a portion
drawn off to maintain a high pH.
The bottoms from the middles column are sent to the product
column, where product benzoic acid is drawn off. The
102
-------
overhead vapors from the product, column are scrubbed with
caustic in a recirculating system similar to that used with
the middles column (see Figure 4-16). Bottoms from the
product column are sent to the tar stripper, where
additional benzoic acid is stripped batchwise from by-
product tar.
The major RWL's for this process are summarized in the
following tabulation;
Waste System
Water of Reaction
1/kkg
247
Aqueous Drain from
Benzaldehyde Wash Tank 52.2
Benzaldehyde Still
Residue
5.0
Vacuum Pump Seal Water 2,200
Middles Column Scrubber
Blowdown 209
Product Column Scrubber
Blowdown 122
TOTAL 2,840
kg/kkg
8.74
11.9
0.91
1.31
2.74
25.6
COD
kg/kkg
15.0
16.1
1.61
1.71
TOC
kg/kkg
6.52
8.34
0.73
1.04
The major source of waste loadings in the process is the
aqueous drain from the benzaldehyde wash tank, where organic
concentrations are greater than 100,000 mg/1. Materials
present include sodium benzoate and other aromatics such as
biphenyls. it is questionable whether this stream could be
incinerated, because of its high alkalinity. However, some
removal of organic wastes may be possible by acidification
of the waste water followed by gravity separation. The
organic wastes removed could then be burned.
103
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Product; Methyl Chloride
Process: Esterification of Methanol with Hydrochloric Acid
Process RVIL Subcategory: B
Chemical Reactions;
CH3OH + HC1 Hetal Catalyst> ^ + ^
Methanol Hydrochloric Acfd Methyl Chloride
Methyl chloride is used primarily as an intermediate during
the production of other chemicals. Primary end-products
include silicones, tetra methyl lead, and cellulose ethers.
Chlorinated solvents such as carbon tetrachloride can also
be manufactured using methyl chloride as a raw feedstock.
Methyl chloride is also used as a catalyst solvent in the
production of butyl rubber.
A process flow diagram for the production of methyl chloride
by esterification of methanol with hydrochloric acid is
shown in figure 4-17.
Methanol and hydrochloric acid are heated and then combined
in the presence of ZnC12 in the reactor. The crude product
is discharged into a fractionator from which the catalyst
stream is recycled bacJc to the reactor. The vapor phase
from the fractionator is then passed through a series of
scurbbing units. Water and caustic solution are used to
scrub the product vapor, which is then sent to a condenser.
Finally, the product is treated with highly concentrated
sulfuric acid to remove the water from the product stream.
The major pollution sources of this process are the waters
discharged from various scrubbing units and the concentrated
sulfuric acid stream from the drying unit. Process RWL
calculated from the flow measurements and the analyses of
waste water samples obtained in the survey periods are
presented in the following tabulation:
104
-------
FIGURE 4-17
METHYL CHLORIDE- ESTERIFICATION OF METHANOL WITH HYDROCHLORIC ACID
o
en
METHANOL
PRE-
HEATER
i
MI
i
r>
REACTOR
t_
HYDROCHLORIC
ACID
PRE-
HEATER
SOLVENT
SULFURIC
ACID
DRYER
WASTEWATER
SCRUBBING
SYSTEMS
CONDENSER
WASTEWATER
^.METHYLCHLORIDE
-------
Plant 1
Plant 2
Plant 3
PROCESS FLOW
liter/kkg
(gal/M Ib)
BOD5 RWL
mg/liter1
kg/Jckg2
COD RWL
mg/liter1
kg/kxg2
TOC RWL
mg/liter1
kg/kkg2
Sample
Period t1
583
69.9
1,210
0.703
119,700
69.8
29,000
16.9
Sample
Period #2
583
69.9
1,940
1.13
112,800
65.8
31,600
18.4
Sample
Period #1
12,000
1,430
1,480
17.7
5,240
62.7
1,070
12.8
Sample
Period #1
842
101
371
0.314
4,090
3.45
1,080
0.908
of
1 Raw waste concentrations are based on unit weight
pollutant per unit volume of process waste waters.
2 Raw waste loadings are based on unit weight of pollutant
per 1000 unit weights of product.
In the foregoing examples, considerable differences in flow
are avident. This may be explained partially by the fact
tnat Plants 1 and 2 utilize scrubbers for removal of
hydrochloric acid while Plant 3 employs a freezing step.
Waste waters common to both installations include pump
leakages and washdowns.
The analytical results also indicate that, in addition to
the parameters shown in the tabulation, water pollution
parameters such as pH, sulfate, chloride, and zinc may be at
levels potentially hazardous to biological treatment pro-
cesses. The low BOD 5 values shown in the tabulation for
Plant 3 may be the result of biological inhibition. The
differences in pollutant loadings among three facilities
visited in the survey period are attributed to differences
in operating efficiencies in the scrubbing and drying units.
Plant 1 data was selected for BPCTCA RWL. The median values
for Plant 1 are 0.92 kg/kkg BOD5, 68 kg/kkg COD and 18
kg/kkg TOC.
An alternative method for producing methyl chloride is by
direct chlorination of methane. Despite the ample
availability of cheaper methane, approximately 65% of all
methyl chloride is produced in the U.S. is produced from
methanol. Part of the reason lies in the economics of
chlorine utilization.
106
-------
Product.; Maleic Anhydride
Process: Oxidation of Benzene
Process RWL Subcategory: B
Chemical Reactions;
V,0r
02 - L * > (CH)2-(CO)2-0 + 2 C02
Benzene Maleic
Anhydride
The market for maleic anhydride is currently growing at a
rate of about 15 percent per year after having remained
static for several years; the growing use of polyester
resins is the main reason for this rapid increase in demand.
Additional uses of maleic anhydride include pesticides, sur-
face coatings, plasticizers, and lubricants. Also, maleic
anhydride is used as a raw material for the production of
fumeric and maleic acid. Fumeric acid finds wide use as a
food acidulant; additional applications of fumeric acid
resemble those of maleic anhydride. Maleic acid is used
solely as a food acidulant.
Essentially all maleic anhydride in the U.S. is based on the
oxidation of benzene. A process flow diagram of this
oxidation process is shown in Figure 4-18. As shown in the
process flow diagram, the production of maleic anhydride is
achieved by a process consisting of;
1. A reaction section, where benzene is oxidized with
air to form maleic anhydride.
2. A recovery section, in which maleic anhydride is
separated from noncondensibles.
3. A dehydration section, in which maleic acid is
dehydrated to maleic anhydride,
4. A fractionation section, in which pure maleic
anhydride is produced.
Benzene is vaporized and fed to a fixed-bed reactor, to
which compressed air is also fed. Typical operating
107
-------
FIGURE 4-18
MALEIC ANHYDRIDE-OXIDATION OF BENZENE
VENT GASES
TO STACK
o
oo
BENZENE
COMPRESSER
AIR
CRUDE
MALEIC
ANHYDRIDE
TANK
I
REFINED
MALEIC
ANHYDRIDE
HEAVY
ENDS
WASHING
WASTEWATER
WATER
WASTE-
WATER
-------
conditions are 25 psig and 400°C. Conversion of benzene is
essentially complete on a once-through basis. Temperature
control is achieved by circulation of a heat-transfer salt
tnrough the shell side of the reactor, with indirect steam
generation. Vanadium pentoxide is used as the catalyst.
Reactor off-gas is cooled in a precondenser to condense as
much of the maleic anhydride as possible from the vapor.
Condensed maleic anhydride is piped to crude storage tanks
prior to fractionation. The remainder of maleic anhydride
is recovered by scrubbing with water, forming maleic acid.
The acid is then dehydrated, thus forming maleic anhydride.
Xylene is added to the dehydrator to form an azeotropic
mixture, thus facilitating dehydration.. The xylene is
recovered from the excess water by decantation.
The recovered maleic anhydride in the separator and
dehydrator is fed to a fractionator, where pure maleic
anhydride is produced. The light and heavy ends are
withdrawn from the dehydration and fractionation columns
respectively, and are disposed of by incineration.
The major water pollution sources of this process are the
excess water withdrawn from the decanter and the periodic
washings from the dehydrator, fractionator, and storage
tanks. Process RWL calculated from the flow measurements
and analyses of waste water samples obtained in the survey
periods are presented in the following tabulation:
Plant 1 Plant 2
PROCESS FLOW
liter/kkg 6,600 2,300
(gal/M Ib) 788 274
BOD5 RWL
mg/literi 63,500 47,000
kg/kkgz 418 108
COD RWL
mg/liter* 90,000 126,000
kg/kkgz 592 287
TOC RWL
mg/literi 23,500 52,500
kg/kkg2 155 120
1 Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
109
-------
2 Raw waste loadings are based on unit weight of pollutant
per 1000 unit weight of product.
Based on the previous process description, the flow and raw
waste loadings for Plant 1 appear extremely high. This may
be partially explained by the fact that waste waters from
the dehydrator are presently discharged rather than recycled
to the scrubber. This flow is approximately 2/3 of the
total flow. These waste waters contain high concentrations
of fumeric acid, thus contributing to a high BOD, COD, and
TOC. It is anticipated that this stream will be recycled in
the near future. At the Plant 2 facility, the dehydrator
water is recycled, and both the flow and pollutant level are
lower than that of Plant 1. The RWL from Plant 2 was
considered as BPCTCA because of the waste reduction
accomplished through in-process controls.
Waste water from Plant 1 is combined with other process
wastes from the facility and is treated by the activated
sludge process. The waste water is fed to the biological
system at a slow, controlled rate because of its high
concentrations. The waste water from Plant 2 is currently
hauled away by a contract disposal service.
110
-------
Product: Acetic Esters (Ethyl Acetate, Propyl Acetate)
Process: Esterification of Alcohol with Acetic Acid and
Catalyzed by Aqueous Sulfuric Acid
Process RWL Subcategory: C
Chemical Reactions:
H ~
>
alcohol acetic acid acetic ester
CHjCOOH - > CH3COOR
where
R is Ethyl (CH3CH2-),
Propyl (CH3CH2CH2-),
or Butyl (CH3CH2CH2CH2-)
Typical Material Requirements:
Basis 1QQO kg Ethyl Acetate 1000 kg Butyl Acetate
Ethyl Alcohol (95X) 620 kg
Butyl Alcohol — 713 kg
Acetic Acid (100*) 688 kg 550 kg
Sulfuric Acid (66°Be') 15 to 150 kg 2,708 kg
Acetic acid esters are used mainly as solvents; the shorter
the alcohol, the lower boiling the solvent. Ethyl acetate
xs a low-boiling solvent for lacquers, and the various
propyl and butyl acetates are popular medium- boiling
solvents used mainly in surface coatings. In all cases,
acetic acid is esterified with ethyl, propyl, or butyl
alcohol in the presence of aqueous sulfuric acid to form the
respective acetate. When the reaction is carried out
continuously in aqueous solution, it is considered to be in
Subcategory C, while batch type processes are considered to
be in Subcategory D.
The process plant visited during the field data collection
program included manufacturing facilities for ethyl, propyl,
and butyl acetate. The acetates were produced in a semi-
continuous manner in two independent systems. Since there
were only two systems, only two different acetates could be
manufactured simultaneously. At the time of the visit,
ethyl acetate was being produced in one system and propyl
acetate in the second.
Ill
-------
The facilities normally are operated continuously for a
period of from 1 to 6 weeks. When it is desired to change
production (turnaround, e.g. from ethyl acetate to butyl
acetate), the reaction stills are washed. Production is
then resumed. Thus, all three acetates are manufactured in
two independent facilities by alternating production within
each facility.
Ethyl acetate is produced by the esterification of acetic
acid and ethyl alcohol in the presence of a catalyst such as
sulfuric acid. A flow diagram for the process is shown in
Figure 4-19. The reaction is reversible and eventually
reaches an equilibrium at about a 67 percent conversion to
ethyl acetate, in order to obtain high yields, the reaction
must be forced to completion by removing the water formed
and employing one reactant in excess. There are many
modifications of the process, but all operate on the same
general principle; that is, acetic acid is reacted with an
excess of ethyl alcohol in the presence of catalytic amounts
of sulfuric acid.
The process is carried out either batch by batch or in a
continuous manner, depending on the nature of the raw
materials and the size of operation. The main variable is
acetic acid concentration, which may range from very dilute
(about 8 percent) to concentrated (about 100 percent).
Generally, 95 percent ethyl alcohol and 50 to 66° Be1
sulfuric acid are used. The ratio of reactants varies
according to the process used and the type of equipment
available. For a batch process, the reactants may be mixed
in the following proportions: 10 parts by weight of 8
percent acetic acid, 10 parts by weight of 95 percent, ethyl
alcohol, and 0.33 part by weight of 50 to 66°Be* sulfuric
acid.
Toe continuous process may be used for any acid
concentration, but it is particularly applicable to the
utilization of dilute acetic acid, such as that obtained
from ethyl alcohol by fermentation. Acetic acid, excess 95
percent ethyl alcohol, and about 1 percent of 66°Be'
sulfuric acid are mixed and continuously passed through a
preheater to an esterifying column. The column and other
equipment are generally constructed of copper. The mixture
is allowed to reflux, and a suitable amount of distillate is
withdrawn from the top of the column, which is held at about
80°C.
The distillate, containing about 70 percent alcohol, 20
percent ester, and 10 percent water (the acetic acid is
consumed in the esterifying column) is run to a separating
112
-------
FIGURE 4-19
ETHYL ACETATE VIA ESTERIFICATION OF
ACETIC ACID AND ETHANOL
SULFURIC
ACID
ETHYL
ALCHOL
ACETIC
ACID
SURFACE
CONDENSER
WATER
RECYCLED TO
SEPARATING
COLUMN
CONTINUOUS WASTEWATER
DISCHARGE
PERIODIC DISCHARGE
OF WASTE ORGANICS
1
ETHYL
ACETATE
-------
column. Here the mixture is refluxed, and a ternary
azeotrope <83 percent ethyl acetate, 9 percent ethyl
alcohol, and 8 percent water) is removed from the top of the
separating column at approximately 70°C.
This homogeneous mixture is run to a proportional mixer,
where it is blended with (approximately) an equal volume of
water. The mixture is allowed to settle in a decanter,
where the two layers that form are separated. The bottom
aqueous layer, containing small amounts of alcohol and
ester, is recycled to the lower part of the separating
column, where the ester and alcohol are removed in the
constant-boiling ternary mixture taken overhead. A waste
water stream is continuously drawn off as bottoms from the
separating column. This stream is necessary to provide a
route for removal of water from the process, it includes
stoichiometric water from the esterification reactions,
dilution water which may be present in the feedstocks,
decanter water, and condensed stripping steam used in all
three distillation columns.
The top layer in the decanter contains about 93 percent
ethyl acetate, 5 percent water, and 2 percent ethyl alcohol.
This layer overflows to a drying column, where a sufficient
amount of the ester is distilled to carry over all the water
and alcohol present. This overhead material is returned to
the separating column for recovery of the ester and reuse of
the alcohol.
Ethyl acetate is withdrawn as bottoms from the drying column
and then is 'either run to storage or redistilled. The
latter is generally necessary to remove copper salts formed
in the copper columns. Other impurities such as higher-
boiling esters may also be present, depending on the purity
of tne raw materials. The yield of ethyl acetate is 90 to
100 percent based on acetic acid. Batch process yields are
about 95 percent.
During the sampling visit, propyl acetate was being produced
in a manner analogous to that described in detail for ethyl
acetate. During the actual production runs, the only
continuous process waste water stream from either unit was
the aqueous bottoms from the separating column. Process RWL
calculated from flow measurements and the analysis of these
streams are indicated in the following tabulation:
Ethyl Acetate Propyl Acetate
PROCESS FLOW
liter/kkg 1,290 1,190
114
-------
gal/M Ib 155 142
BOD5 RWL
mg/liter* 38 7
kg/kkg2 0.049 0.008
COD RWL
mg/liter* 79 10
kg/kkg* 0.102 0.012
TOC RWL
mg/liter1 26 4
kg/kkg* 0.034 0.005
i Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2 Raw waste loadings are based on unit weight of pollutant
per 1000 unit weights of product.
Based on the previous process description, the raw waste
concentrations and subsequent loadings appear reasonable low
for Subcategory C processes. This may be partially
explained by the fact that each of the three distillation
columns in the process utilizes direct steam sparging to
volatilize organic materials and drive them overhead.
Although the recycle of decanter water and overheads from
the drying column for recovery of unreacted alcohol and
product esters is considered good operating practice, it is
questionable whether such low organics concentrations in the
separating column bottoms can be maintained on a steady-
state basis. It should be also noted that both the ethyl
and propyl units were operating respectively at 87.5X and
90.5% of original design capacity. Under such conditions,
each unit may be able to provide sufficient hold-up so that
a bottoms stream which is relatively free of organics may be
withdrawn for limited periods of time.
There are also noncontinuous waste streams associated with
process turnarounds when production shifts from one ester to
another. organic residues from the esterifying column may
amount to approximately 3 kg/kkg of ester product on a
cumulative basis. These organic residues contain no ap-
preciable water and are burned in an incinerator.
In addition, the esterifying columns are normally washed
with a detergent or cleaning agent during production
turnarounds. This waste water is highly concentrated in
organics and amounts to an additional 3 liter/kkg of esters
on a cumulative basis.
115
-------
Although it is clear that these concentrated organic streams
would add to the process RWL, it is not possible to specify
quantitative values for pollution parameters such as BOD5,
COD, etc. The RWL values shown were used in the development
of effluent limitations for ethyl and propyl acetate.
Noncontact waste waters include cooling water flows.
Cooling water is circulated throughout the reaction,
refining, and stripping stills. A loop system is employed.
MaJce-up water for the entire plant is approximately 78,000
liters/kkg of esters (20,000 gal/M Ib). Most of this loss
results from evaporation in the cooling towers. A small
flow is bled from the esters units to prevent a chloride
build-up. This waste water flows to the dilute stream and
eventually to the waste water treatment faciliites.
Condensate from the entire plant is piped back to a
condensate return system for boiler feed water. The total
quantity of condensate is approximately 2,000 kg/kkg of
ester. Condensate from the various processes cannot be
segregated, but it is estimated that condensate from ester
production is less than 1 percent of the pollution abatement
systems.
116
-------
product.; Propylene glycol
Process: Hydrolysis of propylene oxide
Process RWL Subcategory; C
Chenucal Reactions:
H 0 > CH CHOHCH2OH
Propylene water propylene glycol
oxi de
Propylene glycol is by far the most widely used difunctional
alcohol for the manufacture of unsaturated polyesters. This
end use consumes nearly one-half of the propylene glycol
produced in the United States.
Propylene glycol is also used as a cellophane plasticizer.
This market is relatively new, since propylene glycol is a
substitute for ethylene glycol, which has recently been
deemed toxic. Toxicity regulations also dictate the use of
propylene glycol in tobacco. Miscellaneous outlets for
propylene glycol include uses as a binder for cork bottle
caps, as a humectant in cosmetics, and as an intermediate
for propylene carbonate.
Production of propylene glycol is based on the liquid-phase
hydrolysis of propylene oxide, and is shown as a flow
diagram in Figure 4-20. The hydrolysis reaction occurs at
elevated temperature and pressure in the presence of a
sulturic acid catalyst..
By selection of the ratio of feedstock propylene oxide to
water, it is possible to control the production of the mono-
, di-, and higher glycols produced. Excess water is required
for temperature control and to prevent formation of
undesirable by-products.
Reaction products are passed from the reactor to a series of
evaporation and drying towers to remove excess water. This
excess vapor is often discharged to the atmosphere, although
it could be recycled to the reactor.
After passing through the drying operation, the crude
propylene glycol is sent to a series of fractionators. The
first tower removes water and traces of the light ends.
117
-------
FIGURE 4-20
PROPYLENE GLYCOL-HYDROLYSIS OF PROPYLENE OXIDE
00
PROPYLENE
OXIDE
CATALYST-
WATER
PROPYLENE
GLYCOL «—
REACTOR
LU CD
>- O CO
a. co —
STEAM JETS
AND
BAROMETRIC
CONDENSERS
WASTEWATER
CRUDE
DI-PROPYLENE
GLYCOL
STORAGE
STEAM
i
TO ATMOSPHERE
LIGHT ENDS
TO INCINERATION
-»FOOD GRADES
DI-PROPYLENE GLYCOL
HEAVY ENDS
TO INCINERATION
-------
Mono-propylene glycol is then separated, condensed, and
stored as an industrial grade product. The bottoms from the
mono-propylene glycol tower are sent to the crude di-
propylene glycol storage facilities.
Crude di-propylene glycol is then vacuum-distilled. The tops
are recycled to the reactor hydrolyzer to dry the materials
further and to recover glycol product. Bottoms leaving this
first column are further distilled. Food-grade di-propylene
glycol is obtained as bottoms from the second distillation
step. The tops are then further distilled to separate
additional mono-propylene glycol. Both light and heavy ends
are waste products.
Waste waters from the production of propylene glycol are
generated during the evaporation-drying operation and the
distillation processes. Steam ejectors and barometric
condensers are employed in most of the distillation columns.
During the plant visit, samples of these contact process
waste waters were obtained. Process raw waste loads
calculated from flow measurements and analyses of these
streams are indicated in the tabulation below:
PROCESS FLOW
liter/kkg 5,500
gal/M Ib 660
BOD5 RWL
mg/liter1 3
kg/kkg* .016
COD RWL
mg/literi 10
kg/kkg2 .055
TOG RWL
mg/liter1 1
kg/kkg* .006
iRaw waste concentrations are based on unit weight
of pollutant per unit volume of process waste
waters.
2 Raw waste loadings are based on unit weight of
pollutant per 1000 unit weights of product.
These RWL values were used as the basis for BPCTCA.
119
-------
Product; Caprolactam
Process; DSM Caprolactam Process
Process RWL Subcategory; C
Caprolactam is manufactured by a second process referred to
as the Dutch States Mines (DSM) process which differs from
the UBE Jnventa process which was covered in Phase I. A
schematic flow diagram for this process is shown in Figure
4-21. Cyclohexanone is prepared in two stages; 1)
oxidation of cyclohexane to cyclohexanol; 2) catalytic
dehydrogenation of cyclohexanol to cyclohexanone.
Cyclohexane is first oxidized with air in the presence of a
cobalt catalyst. The major oxidation product is
cyclohexanol, with some cyclohexanone produced as a co-
product. Oxidation by-products such as acetic acid, adipic
acid, and cyclohexanol esters are also formed.
Off gases from the oxidizers are scrubbed with kerosene
prior to venting. Unreacted cyclohexane is subsequently
recovered for recycle in a stripper. The process operates
at a cyclohexane single pass conversion of less than 10
percent, so that recovery of unreacted cyclohexane is an
important part of the process.
The liquid effluent from the reactor is sent to a decanter
where the aqueous phase is removed as waste water. The
organic phase is combined with the cyclohexane stripper
overhead.
This mixture is then combined with aqueous saponified liquor
(containing free caustic) and sent to a neutralization tank.
The effluent from this tank is decanted. A heavy layer
containing saponified acids, and esters are drawn off and
sold. This stream is similar in nature to the combined acid
water and caustic water from the Inventa process. Its only
value is for recovery of dibasic acids such as adipic acid.
This can be done by lowering the pH and extracting the
organic acids with a solvent such as methanol.
The light layer from the decanter is sent to the cyclohexane
recovery column. The column overhead is condensed and
separated into aqueous and organic layers. The organic
layer is cyclohexane, which is recycled to the reactor; the
aqueous layer is discharged.
120
-------
FIGURE 4-21
CAPROLACTAM-DUTCH STATE MINES CAPtOlACTAM PROCESS
HYDROGEN VENT
OFF-GAS
r T
00 - Q.
» |*1 i , .
SIS
1 &^ 1 ts,
—
mr.ir.it ° ( j~~|
CYCLOHEXANt "f T | ,
j COUP. | *
*IR DECANT
HATER
AMMONIUM HYDROXIDE
• fc l^~~^~~l
LIGHT ENDS
TO FLARE
NEUT. Ill
TANK ' " 1
1 ^ 1 I 1 1
»= REFLUX 111 ^
1,1 = «»T£R s L- 1 — lrl =
rr is = — 1 ^V" i =
1 1 ^ ^ = S * UJ ^™ UJ
' SS =: C»USTIC ^S S»
^ ' — i — 1 ^^ **TER S3 S3
SAPONIFIED £3 _>S ut>
ACIDS AND FSTFRS * *™
SOLD ' ' 1 ' '
CVCLOHEXANONE
SAPONIFIFD
LIQUOR REFINED
UNE IANK *
CYCLUHEXANUNt ^
^
. OXIME ' 1 •* ""
• RIAC10R III '
HVIUniVI AHINF ShlFITF ' - , • (• » HYDROXIDE ... .
PRODUCED BY NH, OXIDATION 1 * • £ 1 1 — > 1 * »
J 1 X CK 1 1 A W
IE o * ^WATER
CYCLOHEXANONE OX 1 ME PRODUCED BY °* ~ KFIITRAL = = *-
DE
RE
p»
^ SFI
POT
*— WATER
* WATER
HYDROGENATION
ACTOR
T
CVCLOHEXANONE
COLUMN
—1 1
M^H
1 SOLVENT
RECOVERY
HIGH BO
BURNED
Tf
EXTRACT
HATER
NtW U.S.M. PROCESS (ALItRNAIt) l-T,j "..;.L 'I1 - ' J
AQUEOUS LACTAM SOLUTION
• "•• ^ "P1 ts ^j
RECYCLE WATER f
A r^
|
REGENERATION 1
WATER AND ACID SLOWDOWN
i HYDROGEN
^
( * » _• HYDROGENATION , , -
' S5 ' REACTOR ' =
= S "
fc AQUEOUS BACKWASH 1
FROM ION EXCHANGE t .
STOOGE TO FLAKING AND TRUCK LOADING
LERS
N BOI LER
AMMONIUM
SULFATE
RECOVERY
AMMONIUM
SULFATE
CRYSTALS
-------
The bottoms from the cyclohexane column are sent to the
saponification column, where an excess of caustic and water
are needed. The effluent from the saponification column is
decanted into heavy saponified liquor, which is sent back
and mixed with the reactor effluent, and a light organic
layer. The light layer is sent to a series of distillation
columns, which remove light ends, cyclohexane, and
cylcohexanol respectively. The cyclohexanol is sent to a
catalytic dehydrogenation reactor to produce cyclohexanone.
The reactor effluent is sent back to the light-ends column.
The overhead from the light-ends column is burned in a
flare. Hydrogen from the dehydrogenation reactor is passed
through a seal pot containing water and is vented. Water
from the seal pot is discharged to the sewer.
Refined cyclohexanone is combined with ammonium hydroxide
and hydroxylamine sulfate in the oxime reactor to produce
cyclohexanone oxime. The hydroxylamine sulfate is produced
by ammonia oxidation similar to the Inventa process.
It is noted that DSM has also developed an alternative
process to produce cyclohexanone oxime which minimizes the
amount of by-product ammonium sulfate. This process
utilizes hydroxylamine phosphate oxime (HPO) and produces an
amine which may be fed directly to the rearrangement
reactor. The process has been integrated into the total
manufacturing scheme so that the rearrangement reaction can
utilize oxime feed from either the conventional oxime
reactor or HPO.
Excess sulfuric acid in the effluent from the rearrangement
reactor is neutralized with ammonium hydroxide in the
neutralization reactor. The reaction mixture is then sent
to a benzene solvent reactor, in which the crude lactam is
absorbed in benzene and separated from aqueous ammonium
sulfate. The aqueous salt solution is combined with that
from the oxime reactor and sent to a recovery plant to
produce crystals for use in fertilizer.
The lac-cam/benzene extract is mixed with water and sent to a
solvent recovery column. The overhead mixture of benzene
and water is decanted, with benzene recycled to the
extractor and extract water discharged.
An aqueous lactam solution is drawn off as bottoms from the
solvent recovery column. The lactam is then purified by
cation exchange followed by hydrogenation. The ion exchange
resin beds are regenerated by backwashing with water and
acid. The backwash waste water is discharged.
122
-------
The purified lactam is dried in a vacuum evaporator, with
the water recycled to the neutralization reactor. Product
caprolactam is withdrawn from the bottom of the evaporator.
Process RWLgs for the DSM caprolactam process are presented
and discussed at the conclusion of the following section,
which describes the DSM process for manufacturing
cyclohexanone oxime.
123
-------
Product; Cyclohexanone Oxime
Process; DSM Cyclohexanone Oxime Process
Process RWL Subcateqory; C
Dutch States Mines has developed a new process for
manufacturing Cyclohexanone oxime without by-product
ammonium sulfate. This process has been integrated into the
overall caprolactam production scheme to provide
Cyclohexanone oxime feed directly to the rearrangement
reactor as shown by the dashed line in Figure 4-21.
The basic chemistry for the new process is shown in the
reactions listed below:
+ 5 02 —> 4 NO + 6 H20
2. 2 NO + 02 —> 2 N02
3. 3 N02 + H20 —> 2 HN03 + NO
5. NH^OH*
6. H* +
A simplified flow sheet for the process is shown in Figure
4-22. The first processing step is the oxidation of ammonia
with air to nitrogen dioxide (equations 1 and 2). The gases
from the oxidizer are then absorbed in a recirculated
aqueous process solution in the nitrogen gas absorber.
Nitrogen is vented as off-gas from the absorber.
The liquid effluent from the absorber is a buffered aqueous
solution of nitric acid (equation 3), phosphoric acid, and
ammonium nitrate. This mixture is passed to the HPO
reactor, where hydroxylamine is produced (equation 4).
The HPO reactor is a column sparged with compressed hydrogen
gas. Unused hydrogen gas is separated from the catalyst
suspension (palladium metal on carbon), and recycled by
means of a compressor.
The aqueous hydroxylamine solution from the HPO reactor is
sent to a series of stirred tank oximation reactors, where
it countercurrently contacts Cyclohexanone in the presence
124
-------
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slES CYCLOHEXANONE OXIME PROCESS
RCULATED AQUEOUS PROCESS SOLUTION
-------
of toluene. Cyclohexanone oxime is produced as shown in
equation 5. Hydrogen ions liberated by the oximation
reaction are accepted by the phosphoric acid buffer system
(phosphate ions in equation 6). The oximation occurs at a
pH of 1 to 2. Due to the countercurrent flow, nearly
quantitative conversion of cyclohexanone is obtained.
Product cyclohexanone oxime is drawn from the oximation
cascade (lefthand side of Figure 4-22), as a mixture of
oxime, water, and toluene. This product mixture is
contacted with additional toluene in the oxime extractor.
The aqueous bottoms from the oxime extractor is drawn off as
waste water.
Tne oxime-toluene solution from the oxime extractor is sent
to the oxime rectifier, where refined cyclohexanone oxime
product is drawn off as bottoms. This material can be used
directly in the rearrangement reaction to produce
caprolactam.
Tne overhead from the oxime rectifier is sent to a decanter,
where reflux water is drawn off. The separated toluene
layer is split, and part is recycled to the oxime extractor;
the remainder is sent to the process liquid extractor.
In this extractor, the toluene contacts aqueous process
liquid leaving the oximation cascade (right hand side of
Figure 4-22). The organic phase from the extractor is mixed
with fresh cyclohexanone and sent to the oximation reactors.
The process liquid leaving the oximation section must be
purified thoroughly to protect the catalyst in the
hydroxylamine reactor. To achieve this, the liquid is
extracted with toluene and subsequently stripped with steam
in the process liquid stripper. Passage through the
stripping column also removes water formed during the prepa-
ration of hydroxylamine and oxime (equations 4 and 5).
The aqueous process solution is then recirculated to the
nitrous gas absorber. Hydrogen and nitrate ions are
restored in the process liquid by production of nitric acid
(equation 3) .
Calculated process RWL's for Oxanone, Caprolactam, and HPO
Sections of the DSM plant are shown on Tables 4-1 and 4-2.
The data shown here have also been combined to provide a
total RWL for the integrated DSM caprolactam process (bottom
of Table 4-2) .
Examination of the data indicates that the backwash from the
cation exchange resin beds in the Caprolactam Section of the
126
-------
DSM process is a major waste source not found with the
Inventa process. The DSM route uses chemical treatment by
ion exchange and hydrogenation to purify the product lactam,
while the Inventa process uses an extensive vacuum dis-
tillation train for purification. It is not clear as to
whether the physical purification used with the Inventa
process could be substituted for the chemical method used by
DSM. The impurities to be removed may be significantly
different.
The new HPO process incorporated in the DSM scheme also
produces a significantly higher RWL than the hydroxylamine
section of the Inventa process. However, this must be
evaluated considering the fact that by-product ammonium
sulfate formation is minimized.
The DSM waste loads shown in Tables 4-1 and 4-2 are the
basis for BPCTCA for this process.
127
-------
Table 4-1
Process Raw Waste Load Based on DSM Process
Oxanone Section
RWL Based on Cyclohexanone
Saponified Acids & Esters
Light Ends Column Overhead
Cyclohexanol Col. Btms.
Decant Water from Oxidation
Reactor
Reflux Water from
Cyclohexane Column
Hydrogen Seal Water
Flare Condensables
Total (Based on Wastewater
to Sewer)
Caprolactam Section
Extraction Wastewater
Backwash from Cation Exchange
Resin Beds
Slowdown from Recycle
Process Water
Total (Based on Wastewater
to Sewer)
Flow
COD
(liters/kkg) (kg/kkg)
Sold for Product Recovery
Burned in Flare or Steam Boilers
358
478
5.37
8.35
239 6.78
No Data Available
1075
20.5
RWL Based on Caprolactam
Flow
COD
(liters/kkg)
394
1,730
(kg/kkg)
0.39
37J
No Data Ava ilable
2,120
37.5
128
-------
Table 4-2
Process Raw Waste Load Based on DSM Process
Hyam Phosphate Oxime (HPO) Section RWL Based on Cyclohexanone Oxime
Flow COD
(liters/kkg) (kg/kkg)
Aqueous Reflux from 25.5 0.011
Cyclohexanone Oxime Rectifier
Stripper Overhead Condensate 1146 3.43
Wastewater from Oxime Extractor 509 1.02
Miscellaneous Run-off 229 1.83
Total (Based on Waste 1910 6.29
Water to Sewer)
Average Raw Waste Load for Total Plant
Based on Finished Caprolactam Product
Flow BOD COD
Plant Section (liters/kkg) (kg/kkg) (kg/kkg)
Oxanone, HPO, and Caprolactam 7057 39.1 78.1
Process Wastewaters
Hydrogen Seal Water, Drainage 6113 3.2 6.6
From Oxanone, HPO, and Capro.
Ground Drainage Product Loading 630 0.5 0.9
Discharge from Salt Recovery 15,268 4.3 7.4
Section
Total (Based on Water 29,100 47.1 93.0
to Sewer)
129
-------
Product; Formic Acid
Process: Hydrolysis of Formaldehyde
Process RWL Subcategorv: C
Chemical Reaction:
2 HCONH2 + H2SO^ + 2 H20 —* -2 HCOOH +
suIfuric formic ammonium
formamide acid acid sulfate
The main use for formic acid outside the United States is as
a coagulant for natural rubber latex. Domestically, over
half of the total is used in place of sulfuric acid in high-
temperature acid textile dyeing, and to some extent in
leather tanning.
A process flow diagram for the manufacture of formic acid
via hydrolysis of formaldehyde is shown in Figure 4-23.
The feed stock formaldehyde, is stoichiometrically mixed
with water and concentrated sulfuric acid in a pre-mixer,
where the hydrolysis reaction occurs. The mixture of
reaction products is then sent to a series of vacuum stills
where ammonium sulfate in the form of a solid powder is
withdrawn as the still bottoms. The crude formic acid vapor
taken as the overhead from the still is condensed by passage
through a heat exchanger and then sent to a storage tank
before being discharged into a purification still. The
product formic acid is then taken as the overhead from the
purification still, while the residue in the still is
periodically flushed.
The major water pollution source of the process is the
contact water utilized for the water eductor which is used
to pull vacuum for the distillation columns. Although the
residue withdrawn as the bottom of the formic acid
purification still is periodically flushed into sewer lines,
this stream can be disposed of through incineration and is
therefore not included in the raw waste load calculation.
The following represent the median values as determined from
the sampling program:
130
-------
FIGURE 4-23
FORMIC ACID-HYDROLYSIS OF FORMAMIDE
U)
H2S04,
H20
FORMAMIDE-*!
PERIODICAL
FLASHES
(NH4)2S04
BY-PRODUCT
FORMIC
ACID
RECEIVER
WATER
EDUCTOR
CRUDE
FORMIC
ACID
STORAGE
PURIF.
STILL
WA!
•FORMIC ACID
I
PERIODICAL
FLASHES
STEWATER
(COKTACT PROCESS WATER)
-------
PROCESS FLOW
liter/kkg 135,000
gal/M Ib. 16,000
BOD5 RWL
mg/liter1 7^8
kg/kkg2 1.05
COD RWL
mg/literi 33
kg/kkg* 4.5
TOC RWL
mg/liter1 10
kg/kkg2 1.4
iRaw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters. 2Raw
waste loadings are based on unit weight of pollutant per one
thousand unit weight of product.
The high flows and low concentrations shown are from the
water eductor used in the process. It should be noted that
the ammonium sulfate byproduct is not considered in the RWL
calculations.
Most of the formic acid produced in the U.S. is obtained as
a by-product from the manufacture of acetic acid via butane
oxidation. Some of it, however, is made by absorbing CO
either in caustic soda, followed by neutralization or in
methanol, at high pressure, followed by conversion to
formaldehyde and hydrolysis.
132
-------
Product.: Isopropanol
Process: Continuous hydrolysis of propylene
Process RWL Subcategory: C
Chemical Reactions:
CH3CH - CH2 - 75% H2S04 -» CH3CHCH3
propylene
isopropyl
hydrogen isopropyl
sulfate alcohol
Typical Material Requirements
1000 kg Isopropanol
(87% isopropanol azeotrope)
Propylene 820 kg
75% sulfuric acid <1.0 kg
25% caustic 6.5 kg
Benzene <1.0 kg
Isopropanol is widely used in two major areas: feedstocks
for the production of other organic chemicals, and solvents.
Organic chemicals which employ isopropanol as a raw material
include acetone, glycerine, isopropyl acetate, amines, and
hydrogen peroxide. The largest single use for isopropanol,
which accounts for nearly one-half the total production, is
the manufacture of acetone by catalytic dehydrogenation.
As a solvent, isopropanol is used mainly for gums, shellac,
and synthetic resins, competing on a price-performance basis
with ethanol. It is also used widely as a rubbing alcohol.
The process plant visited during the sampling program was
operated continuously except for occasional equipment
washings. Since there is contact with aqueous waters the
process Belongs to Subcategory C. A flow diagram for the
process is shown in Figure 4-24.
The liquid propylene feedstock (65 percent) combined with
recycled hydrocarbons, is absorbed in 75 percent sulfuric
acid to form a solution of diisopropyl sulfate and isopropyl
acid sulfate. The reaction takes place at approximately 400
psig and 60 °C. The sulfated hydrocarbon solution is
converted to an acid solution of isopropyl alcohol, ether,
and polymer by hydrolysis reactions with the addition of
133
-------
frCT
ISOPROPYL
ETHER
DISTILLATION
REFINED
ETHER
DISTILLATION
o
-o
70
O
t>
z
o
I -n
S o
o S
U m
O
•o
-------
dilution water in the hydrolyzer-stripper. Hydrolyzed
reaction products are steam-stripped from the acid and the
vapors are condensed following neutralization with a caustic
solution.
Dilute acid is returned for reconcentration. The liquid
products are then charged to a distillation column, where
isopropyl alcohol is separated from isopropyl ether. The
ether goes overhead while remaining isopropanol is extracted
with recycled water and returned to the crude storage tank.
The ether is then distilled and stored for subsequent sale.
If a dry isopropanol is required, the azeotropic mixture is
broken with benzene.
During the sampling visit, isopropanol was being produced at
the normal rated capacity; thus the waste waters are
considered to be typical of the everyday operation. The
major sources of waste water include the crude isopropanol
waterwash scrubber, the crude isopropanol caustic scrubber,
the isopropanol azeotrope distillation step, and the organic
(benzene) recovery step. Process raw waste loads calculated
from flow measurements and the total pollutant loadings are
indicated in the tabulation below:
Sample Period tl Sample Period *2
PROCESS FLOW
liter/kkg 2,537 2,537
gal/M Ib 304 304
BODS
mg/literi 400 38b
Ib/M Ib2 1.01 .979
COD
mg/literi 1,123 1,132
Ib/M Ibz 2.85 3.13
TOC
mg/literi 508 530
Ib/M Ib* 1,29 1.34
lRaw waste concentrations are based on unit weight
of pollutant per unit volume of process
waste waters.
2Raw waste loadings are based on unit weight of
135
-------
pollutant per 1000 unit weights of product.
Waste streams included in the above calculations are
continuous. However, there are occasional washings which
were not sampled during the plant visit. The organic
stripper is cleaned with water once per month. The cleaning
procedure requires approximately 100,000 gallons of water.
It is believed that this stream should not be included in
the RWL calculations since it can be disposed of by
incineration or combined with the process waste water stream
on an intermittent basis and treated. Although it is not
possible to specify quantitative values for pollution
parameters such as BOD5, COD and TOC for this stream.
Therefore, the jRWL presented in the above tabulation can be
considered as representative of the process. Another
discontinuous source of waste is the yearly cleaning of the
absorption tower which yields approximately 1000 Ibs of
carbon tar for landfill disposal.
Noncontact waste water includes cooling water. The process
uses approximately 100 kg of once-through cooling water per
kg of product. The treatment of the intake cooling water
consists of bar screening and chlorination. Boiler blowdown
is an additional noncontact flow. The blowdown is added to
the cooling water return system. Hot phosphate softening is
employed to treat the boiler feedwater.
The process RWL data presented was used to define BPCTCA.
The wastes from this plant are neutralized and discharged to
the local municipal treatment plant.
136
-------
Product: Oxalic Acid
Process: Nitric Acid Oxidation of Carbohydrates
Process RWL Subcategory: C
Chemical Reaction:
C6H12°6 * 6HN03 "*""* 3HOOCCOOtt + 6NO + 6H20
nitric nitric
glucose acid acid
Typical Material Requirements:
Basis: 1000 kg oxalic acid dihydrate
Glucose (60 percent) 960 kg
Nitric Acid (90 percent) 2,340 kg
Sulfuric Acid (100 percent) 52 kg
The uses for oxalic acid center around its calcium-ion
removal and reducing properties. It is used as a laundry
"sour", as a bleach for removing iron stains from a variety
of materials, and in cleaning compounds. It also finds use
in automobile radiator cleaners, leather tanning and
manufacture, chemical processing, photography, medicinals,
dyes, and inks.
Figure 4-25 is a process flow diagram of oxalic acid
production via nitric acid oxidation of carbohydrates.
Carbohydrates (in the form of corn starch), vanadium
catalyst, steam, sulfuric acid, and nitric acid are added to
the reactor. The reaction time is twelve hours and the re-
actors are sequenced so as to continuously provide products
for tne remainder of the processing equipment. Spent nitric
acid is withdrawn from the reactor and recovered. The
reaction products go to a vacuum crystallizer followed by a
wringer. The liquid effluent from the wringer goes to a
liquid-solid separation step, in which the solids are
recycled to the crystallizer while the liquid proceeds to an
evaporator. The discharge from the evaporator is recycled
to the reactor. The crude oxalic acid crystals from the
wringer are redissolved and then filtered. The solids from
the filter are disposed by landfill while the oxalic acid is
recrystallized under vacuum conditions. The crystals
proceed to a second wringer and the liquid from this wringer
undergoes a liquid-liquid separation step along with liquid
from the previous crystallization step. Some liquid is
recycled to the crystallizer, while the remaining portion
137
-------
FIGURE 4-25
OXALIC ACID-NITRIC ACID OXIDATION OF CARBOHYDRATES
H2S04AND CATALYST
CARBOHYDRATES
Ul
oo
STRONG
MOTHER
LIQUOR
TANK
NITRIC ACID
WASTEWATER
(BARO. COND. )
1
RE-DISSOLVER
WASTEWATER
(BARO. COND.)
WASTEWATER
(BARO.COND.)
HNO
I
3
ER
»
SPRAY
TOWER
NITRIC ACID
PLANT *
OXALIC ACID
-------
proceeds to a second liquid-liquid separation step. Some of
the liquid is recycled to the reactor and the remainder goes
to an evaporator. The discharge from the evaporator is
recycled to the liquid-liquid separator. The oxalic acid
crystals from the wringer are dried and packaged for sale.
The waste waters from this process consist exclusively of
barometric condenser water. This effluent was sampled and
its flow measured. The process RWL calculated from the flow
measurements and the analyses of the samples are indicated
in the tabulation below:
PROCESS FLOW
liter/kkg 436,000
gal/M Ib 52,300
BOD5 RWL
mg/liter1 3
kg/kkg* 1.31
COD RWL
mg/liter1 10
kg/kkg* 4.36
TOC RWL
mg/literi 3
kg/kkg2 1.31
*Raw waste concentrations are based on unit weight
of pollutant per unit volume of process
waste waters.
2Raw waste loadings are based on unit weight
of pollutant per 1000 unit weights of product.
The high flows and low concentrations seen above are a
result of the vacuum system associated with the process.
These data were used to define BPCTCA. The wastes from the
process are currently discharged to a municipal treatment
plant.
The alternate route in the manufacture of oxalic acid is via
sodium formate. Sodium formate is produced by the reaction
of solid sodium hydroxide and carbon monoxide at 200°C and
150 psi in an autoclave. After the reaction is completed,
the pressure is reduced and the temperature is raised to
400°C. The sodium formate is converted into sodium oxalate,
which is then precipitated with calcium hydroxide to form
calcium oxalate. The calcium oxalate is then acidified with
sulfuric acid to form oxalic acid.
139
-------
Product; Calcium Stearate
Process: Neutralization of Stearic Acid
Process RWL Subcategpry; C
Chemical Reactions:
2 C17 H35 C.OOH + 2 NaOH + CaCl2 —*-(C17H35COO)2 Ca + 2 NaCI + 2 H20
sodium calcium
stearic acid hydroxide chloride calcium stearate
Calcium stearate belongs to a group of water-insoluble
metallic soaps. Their water insolubility differentiates
them from ordinary soap, and their solubility or solvation
in organic solvents accounts for their manifold uses. The
precipitation process is the classical method of preparing
metallic soaps, including calcium stearate. It is now used
primarily in making high melting-point soaps which
precipitate as light, fluffy powders and can be recovered by
filtration.
Raw materials for the production of calcium stearate include
stearic acid, sodium hydroxide, and calcium chloride. A
flow diagram of the process is presented in Figure 4-26.
The feedstocks are fed continuously into a reactor, where a
two-stage precipitation process takes place. In the first
reaction, an alkali soap is formed by reacting the stearic
acid with caustic soda. In the second step, the alkali soap
is treated with a water solution of the calcium chloride to
precipitate the calcium stearate. Sodium chloride remains
dissolved in the mother liquor. The resulting slurry,
containing about 10 percent of calcium stearate, is
continuously fed to a filtration step for solids
concentration. Vacuum filters are employed, and the filter
cake is subsequently washed. The partially dried filter
cax.e is then placed in tray dryers, where the remaining
water is removed. The dried soap may then be ground and
separated to produce a powder of uniform particle size.
The major water pollution sources of the process are waste
water discharged from the filtration step and from the
"Battery-Limit" clean-up water. Multiple waste water
samples were obtained during the plant visit in the survey
period. Process RWL calculated from flow measurements and
140
-------
FIGURE 4-26
CALCIUM STEARATE - NEUTRALIZATION OF STEARIC ACID
TO ATMOSPHERE
I
WATER AND STEAM
STEARIC ACID.
NaOH_
CaCI2 .
WATER.
REACTION
AND
PRECIPITATI
VACUUM
FILTRATION
VACUUM
PUMPS
MILLING
DRYING AND
PACKAGING
WASTEWATER
CALCIUM STEARATE
-------
the analyses of these streams are presented in the following
tabulation:
PROCESS .FLOW
liter/kkg 54,100
gal/M Ib 6,460
BOD5 RWL
kg/kkgi 13.8
COD RVIL
kg/kkg4 32.8
TOC £WL
kg/kkg* 23.1
i Raw waste loadings are based on unit weight of pollutant
per 1,000 unit weights of product.
The high flow of the waste stream can be explained by the
fact that a considerable quantity of water is utilized
during the filtration step to wash the solid cake. The
analytical results also indicate high concentrations of
calcium and chloride in the waste streams; these are attri-
buted to excess raw material required by the reaction and to
the reaction by-product, salt.
142
-------
Product: Hexamethylene Tetramine
Process; Synthesis with Ammonia and Formaldehyde
Process RWL Subcategory: C
Chemical Reactions:
6HCHO +
hexamethylene
formaldehyde ammonia tetramlne
Two manufacturing plants were surveyed during the field data
collection program. Flow diagrams designated Plant 1 and
Plant 2 are shown in Figures 4-27 and 4-28.
Both plants combine aqueous formaldehyde and ammonia in a
liquid phase reactor to produce an aqueous solution of
hexamethylene tetramine. The reaction shown above produces
about 0.8 kg of water per kg of hexamethylene, and can be
run with either an excess of ammonia or formaldehyde in the
reaction mixture. The ammonia is used preferably in a
substantially anhydrous state, in either gaseous or liquid
form initially. In view of the high exothermic nature of
the synthesis reaction, the desired control and
stabilization of the reaction temperature is somewhat more
readily achieved if tiie ammonia is introduced in liquid form
so as to take advantage of the cooling resulting from its
vapor i z at i on .
Reaction temperatures of 20°C - 75 °C constitute the range
specified for manufacture of hexamethylene tetramine. The
reaction is conducted at essentially atmospheric pressure,
although slightly superatmospheric pressures may be employed
for operating convenience. The production of hexamethylene
tetramine is carried out in the liquid phase in the presence
of an aqueous solution of the product as a rule. No
catalyst is employed in the reaction of ammonia with
formaldehyde to give hexamethylene tetramine.
In both plants the liquid effluent from the reactor is
concentrated in a vacuum evaporator, where water from the
reactor and formaldehyde feedstock are drawn off. In Plant
1, the overhead from the evaporator is sent to a vapor-
liquid separator with the liquid phase recycled to the
evaporator; the water vapor from the separator is passed
through a noncontact surface cooler and then sent to a
second vapor-liquid separator; and condensate is drawn off
143
-------
FIGURE 4-27
HEXAMETHYLENE TETRAMINE—SYNTHESIS WITH AMMONIA AND FORMALDEHYDE
PLANT 1
STEAM
AQUEOUS
FORMALOENHYDEJ
AMMONIA
STEAM
VACUUM
JET
RECYCLE LIQUOR
STEAM AND
VAPORS
RENTED TO
ATM.
AIR VENTED
SOLID HEXA.
PRODUCT
-------
SfrT
CD n
CD'
HEXA
r
PRE-
CONCENTRATOR
X
m
X
m
Z
>
>
Z
m JJ
ZK
TlO
1 «
CO
-<
Z
CO
-------
from this second separator and discharged to the sewer as
waste water.
A steam jet is used to draw vacuum on the evaporator. Water
vapor from the second separator is drawn off into the steam
line as shown in Figure 4-28. The steam and water vapor
then pass through a jet and are subsequently vented to the
atmosphere.
The concentrated liquid effluent from the evaporator is sent
to a centrifuge where solid crystals of hexamethylene are
separated. The concentrate is recycled to the evaporator.
Hexamethylene crystals from the centrifuge are dried by hot
air and pulverized before being shipped off in bags or
drums. Air from this part of the process is cleaned using
dry dust collectors.
A sampling program covering several weeks' operation at
Plant 1 was conducted. The data on process RWL are
summarized below on a probability basis:
Process RWL Plant 1
Flow EOD5 COD TOC
(liters/kKg) (kg/k£g) (kg/kkg) (kg/kkg)
10% Occurrence 3,200 4.6 18.8 4.5
50* Occurrence 3,200 9.2 29.4 9.8
90* Occurrence 3,200 13.7 40.0 15.1
It should be noted that the RWL data presented from Plant 1
do not include the additional flows and pollutant loads from
carry-over into the steam jet vacuum system. Some
appreciation for the magnitude of these quantities can be
gained by examining the process used in Plant 2.
A flowsheet for this process is shown in Figure 4-28. The
liquid effluent from the reactor is sent to a pre-
conditioner and evaporator operating in series. Water jets
operating in a similar fashion to a barometric condenser
draw vacuum on both units. Water from both jets is
collected in a barometric sump. The warm water from the
barometric sump is circulated through a forced draft
evaporative cooling tower, with the cooled water recycled to
the vacuum jets.
Sulfuric acid is added to the water in the cooling tower to
react with the excess ammonia present. This is done to
control the ammonia vapors which would be stripped off with
the water vapor produced by evaporation in the tower.
146
-------
Ammonium sulfate is produced by the reaction between ammonia
and sulfuric acid.
A blowdown must be taken from the tower because the
evaporation loss is not sufficient to balance the water
formed in the chemical reaction to produce hexamethylene and
the water present in the aqueous formaldehyde feed. It is
also necessary to control the level of dissolved solids
present in the circulating contact cooling water.
A second waste water stream is discharged from a wet
scrubber used with the dryer for the hexamethylene crystal.
The following tabulations summarize the RWL contribution
from both the scrubber discharge and cooling tower blowdown.
Process RWL Plant 2
Flow BOD5 COD TOC
(liter/kkg) (kg/kkg) (kg/kkg) (kg/kkg)
Cooling Tower
Blowdown 5553. 71.5 116 42.7
Scrubber
Blowdown 488. 11.7 112 28^3
Total RWL 6041. 83.2 228 71.0
These data, from Plant 2, are significantly higher, both
witn respect to flow and loading, than those obtained from
Plant 1. The flow and loadings attributed to the wet
scrubber in Plant 2 are not sufficient to explain the
difference between the two plants. Instead, the difference
relates back to the fact that Plant 1 does not condense the
steam used to draw vacuum on the evaporator. Although Plant
1 uses a surface condenser ahead of the vapor-liquid
separator, there may be significant carryover of
contaminants to the steam jet. These contaminants are then
vented to the atmosphere with the uncondensed steam. The
data shown for Plant 2 also may not fully show the magnitude
of this difference in that the flow from the cooling tower
represents a blowdown and does not include evaporation
losses.
The water circulation rate between the cooling tower and
barometric condensers for Plant 2 is approximately 73,900
liters/kkg of hexamethylene.
The RWL data from Plant 1 at 50% occurrence was (median
value) selected as the basis for BPCTCA. These waste waters
are discharged to a municipal treatment plant, as are the
wastes from Plant 2.
147
-------
Product: Hydrazine Solutions
Process; The Raschig Process
Process RWL Subcategory: C
Chemical Reactions: NaOH + C12 —». NaOCl + HCf
sod i urn
hypochlorIde
NaOCl + NH3-^-NH2CI + NaOH
chloramine
NH2C1 + NH3 —^-N2H/, + HC1
hydrazfne
The principal use for hydrazine is as a military missile
fuel in which anhydrous hydrazine is required. Hydrazine
also has a number of nonmilitary applications. The most
important of these is maleic hydrazine, a plant growth
regulator used for tobacco suckering and tree pruning.
Other uses include wash-and-wear finishes, Pharmaceuticals,
anti-oxidants used in foam, hydrazine monobromide, and
soldering flux.
A process flow diagram for the manufacture of hydrazine
hydrate is shown in Figure 4-29.
Sodium hydroxide and chlorine are mixed in a reactor system
to produce sodium hypochlorite. Glue is added to the
solution as an inhibitor until the mix is viscous. A dilute
solution of ammonia (5 to 15 percent) is added until a molar
ratio of 3 NH3 to 1 hypochlorite is obtained. This mixture
forms chloramine which, when reacted with anhydrous ammonia
in a ratio of 20:1 to 30:1, produces hydrazine. The
reaction temperature normally reaches 130°C.
The effluent from the hydrazine reactor is fed to an ammonia
recovery still where excess ammonia is taken off overhead
and recycled back to the reactors. The tails are fed to an
evaporator where concentrated sodium chloride is removed.
The vapors from the evaporator are fractionated to yield (as
bottoms) a commercial grade of hydrazine hydrate.
Anhydrous hydrazine may be produced from hydrazine hydrate
by extractive distillation. Hydrazine salts are produced by
neutralizing hydrazine hydrate with the appropriate acid and
148
-------
FIGURE 4-29
HYDRAZINE HYDRATE-THE RASCHIG PROCESS
VD
SODIUM
WATER
OUS NHq
N H _..
IDE
« ]
1
fc-
\
LU
ce
CD
3= C3
CO 1—
CD CO
>— LU
a: ce
I
LU
•C CD
ce i—
0 CO
— i «t
^E LU
co ce
i
LU
=e
r-j
•«t
ce
C3
=
r
a
i—
CO
«r
LU
ce
t
«c
CD
^
CD
t—
— 1
1—
to
CC
LU
CD
EVAPORATOR
T
.HYDRAZINE
HYDRATE
WASTEWATER
RECYCLE WATER
-------
then dehydrating the resulting slurry. The salts produced
are hydrazine hydrobromide, hydrazine hydrochloride and
hydrazine sulfate.
The waste water stream from this process is a sodium
chloride solution from the crystallizing evaporator.
Process RWL calculated from the flow measurements and
analyses of the waste water obtained in the sampling survey
are indicated in the following tabulation. The extreme high
chloride concentration in the waste water results in an
inhibitory effect on the BOD5 test and, consequently, the
analytical results show a high COD/BOD5 ratio. The low TOC
is due to the lack of organic carbon involved in the
process.
PROCESS FLOW
liter/kkg 30,300
gal/M Ib. 3,630
BOD5 RWL
mg/liter* 300
kg/kkg* 9.09
COD RWL
mg/liten 3,800
kg/kkg* 115
TOC JRWL
mg/liter1
kg/kkg*
iRaw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2Raw waste loadings are based on unit weight of pollutant
per 1000 unit weight of product.
The process RWL shown above is the basis for BPCTCA.
150
-------
Product:: Isobutylene
Process; Extraction with Sulfuric Acid from a Mixture of Ct*
Hydroc arbon s
Process RWL Subcategory: C
Hign-purity isobutylene is required for applications such as
the production of butyl rubber and the alkylation of
aromatics. In the U.S., the most common process for
manufacturing pure isobutylene is extraction with 65 percent
sulfuric acid. The feedstock is usually a mixed C4 cut from
a refinery. The process is continuous and is characterized
by extensive contact between water (as H2SCW) and
hydrocarbons. As such, it is assigned to process
Subcategory C (Aqueous Phase Reactions). It should be noted
that regeneration of the sulfuric acid absorbent is
considered as an integral part of. the process.
A flow diagram for the extraction process is shown in Figure
4-30. The process consists of a countercurrent extraction
system. The effluent from the final stage is flashed and
goes to a regenerator where heat reverses the reaction and
regenerates both acid and isobutylene. Temperature is kept
below the point where polymerization would become a problem.
Sulfuric acid is removed from the bottom of the regenerator
and recycled after reconcentration. The regenerator off-
gas, containing isobutylene and some light polymer plus t-
butyl alcohol, is fractionated to produce 99+ percent
isobutylene, and the bottoms can be further fractionated
into t-butyl alcohol and diisobutylene.
Process RWL's for isobutylene extraction are summarized in
the following tabulation:
PROCESS FLOW
liter/kkg 20,400
gal/M Ibs. 2,440
BOD5 RWL
ing/liter1 669
kg/kkg2 13.6
COD RWL
mg/liter1 3,150
64.1
151
-------
FIGURE 4-30
ISOBUTYLENE—EXTRACTION FROM C4 HYDROCARBONS WITH SULFURIC ACID
CjCUT
REACTORS
H2S04MAKEUP
K
K ALCHOL
STRIPPER
T
WASTEWATER
FLASH
DRUM
REGENERATOR
JL
in
NEUTRALIZER
JL
NaOH
SPENT CAUSTIC
REGENERATED ACID
/--BUTYL ALCHOL SOLUTION
SPENT C4 S
TO NEUTRALIZATION
ISOBUTYLENE PRODUC1
PURIFICATION 1 1
1 1 i
-*
§_;
(
WATE
*
ALOC
POLYMER
GASOLINE
EXTRATION
TOWER
-------
TOC jRWL
mg/liter* 633
jcg/kkg* 12.9
*Raw waste concentrations are based on unit weight
of pollutant per unit volume of process
waste waters.
2 Raw waste loadings are based on unit weight of
pollutant per 1,000 unit weights of product.
This process RWL data is the basis for BPCTCA. The wastes
from this process are combined with those from other
processing areas and treated by the activated sludge process
before discharge.
153
-------
Product: Sec-Butyl Alcohol
Process: Sulfonation and Hydrolysis of Mixed Butylenes
Process RWL Subcategory: C
Chemical Reactions;
CH3CH - CHCH3
Butene-2
CH3CH2CHCH3
HSO/,
H2SOj,
Sulfurlc
Acid
H20
Sec-Butyl
Sulfate
Water
CH3CH2CHCH
Sec-Butyl
Sulfate
CH3CH2CH(OH)CH3 +
Sec-Butyl
Alcohol
Sulfurlc
Acid
Secondary butyl alcohol is made from mixed butylenes.
However, because of its alternate uses, isobutylene is
normally extracted from the C4 feedstock prior to the
manufacture of secondary butyl alcohol. This is also done
to prevent the formation of excessive quantities of tertiary
butyl alcohol from isobutylene.
Normal butylenes are first absorbed by concentrated sulfuric
acid (75 percent) to form isobutyl sulfate. This is
subsequently hydrolyzed with water to secondary butyl
alcohol and dilute sulfuric acid. A flow diagram for the
process is shown in Figure 4-31. The extensive requirements
for contact water usage make this continuous process typical
of Subcategory F. The reconcentration of sulfuric acid for
recycle is considered an integral part of the process. It
should also be noted that this process for secondary butyl
alcohol is analogous to that used to produce isopropyl
alcohol from propylene.
The weak acid bottoms from the hydrolysis are reconcentrated
by multistage vacuum evaporation. Normally, three
evaporators in series are used to bring the acid
concentration back to 75 percent strength. However, during
the sampling program, only two were in service, with the
final stage down for cleaning. This type of operation is
possible by pulling a higher vacuum on the first two
evaporators.
The overhead vapors from the first evaporator are drawn
through a surface condenser which utilizes noncontact
154
-------
FIGURE 4-31
SEC —BUTYL ALCOHOL—SULFONATION AND HYDROLYSIS OF MIXED BUTYLENES
SULFURIC ACID (85%)
BUTYLENES
CO
o±
a
GO
VENT GASES
(RECYCLE)
WATER
STEAM-
DILUTION
TANK
ACID
RECOVERY
DILUTE ACID
SEC-BUTYL ALCOHOL
LLJ O
CC CJ
WAS'TE
-------
cooling water. The noncondensible vapors are entrained in
two barometric condensers operating with steam jet vacuum
pumps in series. The second- and third-stage evaporators
are also equipped with this condenser-steam jet arrangement.
Apart from dehydrogenation to butadiene, secondary butyl
alcohol production is the main end use for normal butylenes.
Secondary butyl alcohol itself is used mainly as a solvent
or to make secondary butyl acetate or methyl ethyl ketone.
It should be noted that the alcohol product is obtained as
an aqueous solution in this process. The product is really
an azeotropic binary mixture drawn as a side stream from the
crude secondary butyl alcohol scrubber-stripper. It
contains approximately 70 wt percent (36 mole percent)
alcohol and 30 wt percent (64 mole percent) water, and is
withdrawn at a minimum boiling point of approximately 90°C.
Dehydration of the alcohol is accomplished in subsequent
processes, and this waste water is not included in the
wasteload computed for the alcohol process.
During the field data collection program, two plants
utilizing the previously described process were sampled.
The following brief tabulation summarizes the RWL for each
plant:
Plant 1 Plant 2
PROCESS FLOW
liters/kkg 64,900 626
gal/M Ib
BODS RWL
mg/literi 374 22,800
kg/kkg2 24.3 14.2
COD RWL
mg/liter* 3,280 62,000
kg/kkg« 213 38.8
TOC RWL
mg/liten 665 38,300
kg/kkg* 43.2 23.9
*Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2Raw waste loadings are based on unit weight of pollutant
per 1,000 unit weights of product.
The RWL from Plant 2 was used to define BPCTCA. This plant
utilizes much more internal recycle than Plant 1.
156
-------
Product: Acrylonitrile
Process: Ammonoxidation of Propylene
Process RWL Subcategory: C
Chemical Reaction:
2 CH2CHCH3 + 2 NH3 + 3 02 —•>• 2 CH2 CHCN + 6 H20
propylene Ammonia acrylonltrile
Acrylonitrile is used in the manufacture of acrylic fibers,
Acrylonitrile- Butadiene-Styrene (ABS) and Stryene-
Acrylonitrile (SAN) resins, and nitrile rubber.
A typical process flow diagram for the manufacture of
acrylonitrile via ammonoxidation of propylene is shown in
Figure 4-32.
Raw materials for the production of acrylonitrile are
propylene, air, and ammonia. These feeds are introduced
into a fluid bed catalytic reactor operating at 5 - 30 psig
and 200°C to 260°C. The reactor effluent is scrubbed in a
counter-current absorber and the organic materials are
recovered from the absorber water by distillation. Hydrogen
cyanide, water, light ends, and high boiling impurities are
removed from the crude acrylonitrile by fractionation to
produce a specification acrylonitrile product.
Although the actual ammonoxidation reaction is vapor-phase,
the process was considered within Subcategory C because of
the aqueous separation and purification train.
The major water pollution sources of this process are the
process waste waters discharged from the steam stripping
columns as shown in the process flow diagram. Process RWL
calculated from flow measurements and analyses of the waste
streams are indicated in the following tabulation:
157
-------
85T
REACTOR
I
ABSORBER
ACRYLONITRILE
RECOVERY COLUMN
ACETONITRILE
RECOVERY COLUMN
T
C-O
CO
X* CO
C-3 =0
n
70
-<
O
30
IJ W
O w
Z
LIGHTS COLUMN
PRODUCTS COLUMN
70
O
•o
-------
Plant_L Plant 2 Plant 2 Plant 3
Sampling Periods
#1 #2 »3 tV t2 #1
PROCESS FLOW
liter/kkg 3,320 3,920 3,920 6,590 4,010 2,820
gal/M Ib 471 471 471 790 480 338
BOD5 RWL
mg/literi 18,000 18,700 19,300 3,330 13,900
kg/kkg2 71.7 73.3 75.8 21.9 55.5
COD RWL
mg/literi 57,400 60,300 60,700 21,100 36,200 41,100
kg/kkg« 229 237 238 139 145 116
TOC RWL
ing/liter* 25,600 24,000 25,100 8,700 15,300 19,100
kg/kkg* 102 94.2 98.6 57.3 61.2 53.9
1 Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2 Raw waste loadings are based on unit weight of pollutant
per 1000 unit weight of product.
The foregoing data indicate that the RWL of Plant 1 is
higher than that of Plants 2 and 3. This difference is
attributed to the discharges by Plant 1 of light
hydrocarbons that are removed as the overhead from the
acetonitrile purification column comes into the sewer lines.
The analytical results from the sampling survey also reveal
that, in addition to the pollution parameters shown in the
above tabulation, the concentration of parameters such as
nitrogen, sulfate, and cyanide may be at levels potentially
hazardous to the biological pretreatment process.
An average of the RWL data from Plants 2 and 3 was
considered as the basis for BPCTCA. It should be noted that
all of the plants surveyed currently use deep-well
injections to dispose of wastes from the manufacture of
acrylonitrile.
The alternative routes for the manufacture of acrylonitrile
include: 1) catalytic dehydration of ethylene cyanohydrin;
2) catalytic reaction of acetylene and hydrogen cyanide; and
3} catalytic reaction of propylene with nitric oxide.
However, present practice concentrates exclusively on the
ammonoxidation of propylene.
159
-------
Product: Cresol (Synthetic)
Process: Methylation of Phenol
Process RWL Subcategory; C
Chemical Reaction;
C6H5OH + CH3OH > CH-CgfyOH + H20
phenol methanol cresol
Cresol (cresylic acid) is an isomeric mixture (o-, m-, and
p-cresol) obtained by refining the phenolic constituents
present in coal tar, refining the petroleum acids formed
during the thermal and catalytic cracking of petroleum, or
by producing cresols synthetically. Cresols are used
primarily as raw materials for the production of phenolic
resins, tricresylphosphate, disinfectants, and solvents.
The facility visited during the field survey produced an
isomeric mixture of cresols by the methylation of phenol.
Figure 4-33 is a process flow diagram of this production
technique.
The first step in the process is the preparation of the
reactor feed. Fresh and recycled methanol and phenol are
mixed in a weight ratio close to 2.5:1. The mixed stream is
then vaporized, and condensing Dowtherm vapors are used to
vaporize and heat the feed to 300°C. The reaction is
carried out at atmospheric pressure in a mixed-bed reactor
which contains activated alumina catalyst. The heat of
reaction is removed by passing liquid Dowtherm through the
tubes imbedded in the mixed bed of the reactor. (The heat
of reaction is approximately 20 Kcal/mole.) Some of the
heat evolved by the reaction will be taken up as sensible
heat by the reactants, which are heated from 300°C to the
reaction temperature of 350°C. The contact time in the
reactor for 52 percent reaction completion is less than 30
seconds. A typical reaction mixture distribution on a
water-free basis is given below.
Weight %
Phenol 48
o-Cresol 30
m- and p-Cresol 12
2, 6-Xylenol 15
Anisoles and Hexamethylbenzene 5
160
-------
T9T
METHANOL
DISTILLATION
COLUMN
COLUMN
COLUMN
CD —
— CO
O
30
m
1
ATION
i
ATION
i
1
m s*
CO Z
°°
1-0
en
X
i —
i —
j
1
»
BENZENE
DISTILL
COLUMN
.
DISTILL
COLUMN
.
PHENOL
DISTILL
COLUMN
i
DISTILL
COLUMN
mow
i
.
UION
1
UION
1
UION
Z
X
3 co
? co
O
Z
O
X
m
Z
O
I
CO
-------
The vapors leaving the reactor are condensed and cooled to
about 25°C, and then sent to a phase separator. The vapor
space is provided with a vent in order to periodically
remove any noncondensables (CO2, CHJ4) which might be
produced in the reactor. The weight percent of water in the
liquid phase is below 10 percent.Consequently, an aqueous
phase will not appear, because the water will stay in the
organic phase. The solubility level of water in phenol is
close to 34 gms/100 gms phenol at 25°C. The presence of
cresols and xylenol undoubtedly decreases the solubility
limit, but the decrease is not sufficient to form a separate
aqueous phase.
The liquid phase is sent to an extraction column in which
benzene (containing some methanol) is circulated
countercurrent to the liquid product stream. The phenol,
cresols, xylenols, and by-products are transferred to the
benzene phase, while the water and the methanol form an
aqueous phase.
The aqueous phase is then sent to a methanol recovery
column, in which methanol is removed as the distillate,
while water (with small amounts of phenol) remains as
bottoms. The methanol is recycled to the reactor feed-
preparation section, while the water is discharged. The
organic phase, containing benzene and the reactor products,
is sent to the benzene recovery column, where this solvent
is distilled overhead and recycled to the extraction unit.
This column is operated at atmospheric pressure, with an
overhead temperature close to 75°C. Cooling water is used
in the condenser, and condensing Dowtherm vapors are used in
the reboiler.
The bottoms stream leaving the solvent recovery still is
sent to the distillation column, in which anisole and light
by-products are removed in the overhead. Phenol is
recovered in a subsequent distillation step and recycled to
the reactor section. The bottoms from the phenol recovery
column are then sent to the product recovery section. In
the first column, o-cresol is recovered as distillate; in
the second, m-and p-cresol isomeric mixture is distilled
overhead. The bottoms are sent to the 2, 6-xylenol column,
in which this co-product is distilled off, while the bottoms
containing the heavier by-products (such as hexamethyl-
benzene) are sent to organics disposal.
The major water pollution source is the water stream
withdrawn as the bottom of methanol recovery column.
Process RWL's calculated from flow measurements and analyses
162
-------
of the waste water samples are indicated in the following
tabulation:
PROCESS FLOW
liter/kkg 334
gal/M Ib. 40
BOD5 RWL
mg/literi 143,000
kg/kkg* 47.7
COD RWL
mg/literi 303,000
kg/kkg* 101
TOC jRWL
mg/literi 104,000
kg/kkg* 34.7
*Raw waste concentrations are based on unit weight
of pollutant per unit volume of process
waste waters.
2Raw waste loadings are based on unit weight of
pollutant per 1,000 unit weights of product.
The analytical results also indicate that the phenol
concentration in the waste stream is at a level which may be
hazardous to biological treatment processes if not properly
acclimated. The waste stream can either be pretreated with
lime to form calcium phenolate before being discharged into
a biological treatment processes or can be steam stripped to
reduce the phenol concentrations.
The process RWL is the basis for BPCTCA. The waste from the
plant is currently discharged to the municipal treatment
plant.
163
-------
Product: p-Aminophenol
Process: Catalytic Reduction of Nitrobenzene
Process RWL Subcategory: C
Chemical Reactions;
NO,
n'i trdbenzene
metal
catalyst
C6Hj,(OH)NH2
p-aminophenol
+ HVO
Typical Material Requirements;
Basis
Nitrobenzene
Sulfuric Acid
Surfactant
Anhydrous Ammonia
Toluene
Hydrogen Gas
Nitrogen Gas
Antioxidants
By-Products
Aniline
1000 kg p-Aminophenol
1800 kg
1550 kg
20 kg
500 kg
80 kg
220 kg
p-Aminophenol is versatile in its use as a dye intermediate.
It can be used in the preparation of disperse, nitro, acid,
mordant, direct, sulfur, and oxidation dyes. It is also
widely used as a photographic developer. The by-product
aniline produced during the reaction also has wide uses in
the dye, dfug, rubber, plastics, and animal-feed industries.
Production of p-aminophenol is based upon the reduction of
nitrobenzene with hydrogen in the presence of aqueous
sulfuric acid and a metal- containing catalyst (platinum,
palladium, or mixtures of the two), as shown in Figure 4-34.
The raw materials (nitrobenzene, deionized water, hydrogen
gas, sulfuric acid, surfactants, and the metal catalyst) are
fed into a reactor at a temperature ranging from about 60°
to 120°C. Prior to completion of the reaction, the
reduction of the nitrobenzene is interrupted for catalyst
recovery and recycle. During the reaction a distinct
interface forms between the reaction products and the
164
-------
FIGURE 4-34
PARA-AMINOPHENOL- CATALYTIC REDUCTION OF NITROBENZENE
NITROBENZENE
WATER
SUiFURIC ACID
H2AND N2 GASES
SURFACTANT
.SPENT CATALYST
TO RECOVERY
BY-PRODUCT,ANILINE
.DISTILLATION
BOTTOMS TO LANDFILL
NITROBENZENE
CATALYST
RECOVERY
RECYCLE
SOLVENT
RECOVERY
& RECYCLE
PURIF1CATI
AND
SOLATION
CATALYTIC
REACTOR
ANHYDROUS
AMMONIA
TOLUENE
PARA- AMINOPHENOL
.WASTEWATER
—
CE
EC
D
«
LU
1 .
-»
LU
fs ^—
i— oe
OO CD
-a «t
CVI LU
1 .
TO LANDFILL
ANTIOXIDANTS
-------
catalyst-containing nitrobenzene. To recover the catalyst
the nitrobenzene layer is separated and used in a subsequent
reduction step.
The reaction products proceed to a purification and
isolation step. Additional materials (anhydrous ammonia and
toluene) are added to facilitate separation of the by-
product aniline from product p-aminophenol. After isolation
of the aniline, solvent is recovered and recycled to the
purification and isolation step. Following purification,
the p-aminophenol is dried and packaged for sale.
The major pollution sources of the process are the waste
waters generated during the aniline recovery step and the p-
aminophenol drying step. These waste waters are collected
and passed through two evaporators connected in series.
This evaporation process separates the very concentrated am-
monium sulfate wastes for landfill disposal. It was claimed
by the plant which was visited during the sampling survey
that the evaporation process should be considered as
pollution abatement facilities rather than as part of the
manufacturing process. However, separate samples of
influent to the evaporator and effluent were analyzed and
the jRWL's are presented in the following tabulation.
Influent to Evaporators Effluent from Evaporators
Sample Sample Sample
Period t1 Period t2 Period #1
PROCESS FLOW
Liter/kkg
gal/M Ib
BOD5 RWL
mg/liter1
kg/kkg*
COD RWL
mg/liter1
kg/kkg*
TOC RWL
mg/liter1
kg/kkg2
15,000
1,800
59,300
890
115,000
1,725
33,600
505
15,000
1,800
59,300
886
101,000
1,508
27,100
407
4Raw waste concentrations are based on unit
pollutant per unit volume of process waste waters,
2Raw waste loadings are based on unit weight of
per 1000 unit weights of product.
12,600
1,510
3,300
41.6
5,850
73.7
1,730
21.7
weight of
pollutant
166
-------
The process RWL based on the effluent from the evaporators
was considered as the basis for BPCTCA. The effluent from
the evaporators (aqueous condensate) is combined with waste
waters from other processes and treated in an activated
sludge plant prior to discharge to surface waters.
Noncontact waste waters include cooling tower blowdown and
boiler condensate. Each of these wastestreams is bled
continuously for the control of dissolved solids. The
streams are combined with the treated process waste waters
and eventually discharged to a receiving stream.
p-Aminophenol can also be prepared conveniently by the
Beehamp method of reducing p-nitrophenol in the presence of
iron filings in an acid medium. Alternatively, the product
may be prepared by catalytic hydrogenation of p-nitrophenol,
by treatment of phenylhydroxylamine with an acid catalyst,
(such as sulfuric acid), by reduction of azoxybenzene in
acid solution, and by treatment of p-chlorophenol with
ammonia.
167
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Product: Propylene oxide
Process: Chlorohydrin Process
Process RWL Subcategory; C
Chemical Reactions;
HOC1
propylene hypochloric acid propyl
chlorohydrin
2 HOCH2CH2CH2C1 + Ca(OH)2 - > 2 C^CH - CH£ + CaC12 + 2 HO
^O/
propyl ' ime propylene oxide calcium water
chlorohydrin chloride
The most important outlet for propylene oxide is in the
manufacture of propylene glycol. It is also used during the
production of polyethers, which are in turn used in the
manufacture of urethane foams and elastomers.
The manufacture of propylene oxide from propylene is similar
to that of ethylene oxide by the chlorohydrin route. In
fact, many propylene oxide manufacturing facilities are
converted ethylene oxide plants which were rendered obsolete
by the advent of direct oxidation. In recent years,
considerable research has been undertaken to discover a
viable process for making propylene oxide without using
chlorine. A number of alternatives have been developed,
including epoxidation of propylene by means of hydroperoxide
and direct bxidation of propylene.
Production of propylene oxide by the chlorohydrin process
involves a reaction between propylene and chlorine. The
process flow sheet is shown in Figure 4-35. The raw
materials are fed into a reactor and water is added. The
reaction products are primarily chlorohydrin and
dichlorohydrin. Vent gases from the reactor are passed
through a water scrubber. A second stage caustic scrubber
is also employed to neutralize potential acid carry-over in
the off-gases.
Following the caustic scrubbing, the gases are passed to an
oil absorption unit where propylene dichloride is
168
-------
69T
-o
ye
O
O
X -n
S O
O C
X 70
r- m
O .
*» ^
O w
x o,
30
O
CO-
CA
-------
selectively concentrated and recovered. (An activated
carison adsorption system may be substituted for the oil
absorption unit.) other reactor gases, such as a propylene
and propane are often vented to a fuel gas supply. At some
installations, pure propane may be recovered in a dehydrator
(activated alumina).
Reaction products, containing mainly propyl-chlorohydrin,
are sent to a saponificatibn. reactor. A lime slurry is fed
into the reactor along with live steam. In the reactor,
propyl-chlorohydrin is converted to propylene oxide.
Dichlorohydrin is also converted to propylene dichloride,
which may be recovered as a by-product. Following the lime
addition, the products are passed through a stripper. The
products (propylene oxide and propylene dichloride) are
separated from unreacted lime and calcium chloride. The
unreacted lime solution is passed through a clarifier from
which the underflow, containing unreacted lime, is recycled
back to the saponification reactor; the overflow is
discharged as waste water.
The product is first passed through a recovery tower, where
propylene oxide is separated. The underflow, containing
propylene dichloride, is sent to a steam stripper where
propylene dichloride is separated from other impurities.
The propylene dichloride is combined with the propylene
dichloride separated from the off-gases. Bottoms from the
stripper constitute a second major waste stream.
Production facilities for propylene oxide were visited
during the sampling period, and samples of the process waste
waters were obtained. Process raw waste loads calculated
from flow measurements and analyses of these waste waters
are indicated in the tabulation below:
Plant 1
Sample
Period #1
Sample
Period *2
Plant 2
Sample
Period #1
Plant 3
Sample
Period f1
PROCESS FLOW
liters/kkg 60,000
gal/M Ib. 7,150
BODS RWL
mg/liter*
kg/kkg*
COD RWL
mg/liter1
kg/kkgz
290
17.2
2,480
148
50,200
6,020
575
28.9
2,740
138
69,300
8,300
480
33.2
1,680
116
66,000
7,910
578
38.1
2,580
170
170
-------
TOC RWL
mg/literi 310 320 365 385
Jtg/kxg 18.6 16.0 25.3 25.4
NOTE: iRaw concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2Raw waste loadings are based on unit weight of pollutant
per 1000 unit weights of product.
A plant average of the values presented above was used as
the basis for BPCTCA. The waste waters from all three
plants are currently combined with wastes from other
processes and pumped to settling basins from which they are
discharged. The high flows may be partially explained by
the fact that a large quantity of water is required in the
reactor and also in the many scrubbers. Furthermore, a
large quantity of stoichiometric water is formed during the
reaction.
It is possible that both pollutant loadings and flows may
vary at other production facilities. The pollutant loadings
may be greatly increased if propylene dichloride is not
recovered following separation of the propylene oxide. At
such an installation, the flows would probably be lower
since the propylene dichloride stripper would not be
required.
An additional feature of the process plant visited during
the sampling period which may differ at other installations
relates to the recycling of unreacted lime. A clarifier had
been installed to remove lime and calcium chloride from the
waste water. These materials were then recycled to the
reactor, thus reducing the total flow and the pollutant
loadings. This practice was considered as part of the
process since required materials were recycled.
171
-------
Product; Pentaerythratol
Process: Aldehyde Condensation
Process RWL Subcategorv; C
Chemical Reactions;
4HCHO + CH3CHO + NaOH — +• CfCt^OH)!, + HCOONa
sod i urn sod i urn
Formaldehyde acetaldehyde hydroxide pentaerythrf tol formate
The most important end use of pentaerythritol is in the
manufacture of alkyl resins. Next in importance are
pentaerythritol resin esters, which are used in floor polish
and in flexographic inks. Other applications of
pentaerythritol esters are in the manufacture of fire-
retardant paints, use as high pressure lubricants, and
production of PVC plasticizers of low volatility suitable
for use in wire insulation.
A typical process flow diagram for producing pentaerythritol
by aldehyde condensation is shown in Figure 4-36. The major
pollution sources of the process are residue from the
distillation column and mother liquors withdrawn from the
purification units. The condensates from the steam jets
which are used to pull vacuum are recycled back to the
process, and are not considered waste waters. The process
RWL calculated from the flow measurements and analyses of
waste water samples obtained in the sampling period are
presented in the following tabulation;
PROCESS FLOW
liters/kkg 10,200
gal/M Ibs 1,220
BOD5 RWL
mg/literi 38,100
kg/kkg* 390
COD RWL
mg/literi 155,000
kg/kkgz 1,580
172
-------
FIGURE 4-36
PENTAERYTHRITOL —ALDEHYDE CONDENSATION
RECYCLE WATER
WATER
VAPOR
VENT
ACETALDEHHDE
FORMALDEHYDE
WATER
10
CAUSTIC
REACTION
1
DISTILLATION
RECYCLE FORMALDEHYDE
PURIFICATION
PENTAERYTHRITOL
WASTEWATER STREAM
-------
TOC RWL
mg/literl 81,200
830
iRaw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2Raw waste loadings are based on unit weight of pollutant
per 1000 unit weights of product.
The above process RWL data were used as the basis for
BPCTCA. The waste water from this process is combined with
other wastes for treatment in an activated sludge plant.
174
-------
Product: Saccharin
Process: Synthesis from Phthalic Anhydride Derivatives
Process RWL Subcategory: C
Saccharin is the imide of the mixed anhydride of o-
carboxylbenzenesuifonic acid. It is a powerful sweetening
agent, having a sweetness from 550 to 750 times stronger
than cane sugar. Saccharin has no food value and is used as
a sugar substitute in many applications.
A continuous process for the manufacture of saccharin from
pnthalic anhydride derivatives is shown in Figure 4-37.
The phthalic anhydride derivatives along with water and a 50
percent sodium hydroxide solution enter the reactor. A
metal catalyst is used during the reaction. The fumes
leaving this reactor axe scrubbed with water and ,sodium
hydroxide. The resultant waste water flows to a
neutralization tank, where caustic is added to raise the pH.
The product mixture from the first reactor is then
chlorinated in the second reactor, and the fumes from this
reaction include chlorine, hydrochloric acid, and water
vapor. These fumes are also piped to the aforementioned
caustic scrubber. A portion of the metal catalyst is
removed from the second reactor for regeneration. The
catalyst is treated with sodium hydroxide and then filtered.
The filtrate goes to the neutralizer, while the catalyst is
recycled to the first reactor.
The products from the second reactor are reacted with NH3 in
the third reactor, while any unreacted ammonia is vented to
an absorber where the ammonia is absorbed with water and
returned to the third reactor. An organic solvent is used
to extract the product saccharin from the reaction mixture.
Tne raffinate stream from the extraction operation is first
neutralized and then distilled to recover the solvent. The
extracted phase is steam stripped to recover more solvent,
which is condensed and recycled back to the third reactor.
The aqueous solution leaving the stripper is precipitated by
the addition of hydrochloric acid. The precipitate is
further concentrated by filtration, crystallized under
vacuum conditions and then dried to produce the product
saccharin. The filtrate is neutralized by a caustic
solution prior to its discharge to the sewer.
The major water pollution sources of the process are the
waste waters from the caustic scrubber, catalyst filtration
175
-------
FIGURE 4-37
SACCHARIN- SYNTHESIS FROM PHTHALIC ANHYDRIDE DERIVATIVES
CHLORINE
AMMONIA
VENT
GASES
HCL
PHTHALIC ANHYDRIDE
DERIVATIVES
CAUSTIC SOLUTION—
HATER-
CAUSTIC •
SOLUTION
-
CK
UJ
r-j
=3
UJ
»-
1
•-» CATHYST
REGENERATION
1
t
CATALYST
FILTRATION
"EUTRALIZER
RODUCT
KASTEWATER
»ASTE»ATER
KASTEKATER
-------
unit, solvent recovery still, product filtration unit, and
barometric condenser. Process RWL's calculated from flow
measurements and analyses of the waste water streams are
presented in the following tabulation. The analytical
results also indicate that, in addition to the parameters
shown in the tabulation, pollution parameters such as
nitrogen, sulfate, chloride, and metals may be at levels
which can be potentially hazardous to the biological
treatment process.
PROCESS FLOW
liter/kkg
gal/M Ib
BOD5 RWL
mg/liter1
kg/kkg*
COD RWL
mg/liter1
kg/kkg2
TOC RWL
mg/liter1
kg/kkgz
269,000
32,200
940
253
3,270
879
1,430
384
iRaw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2Raw waste loadings are based on unit weight of pollutant
per 1,000 unit weights of product.
177
-------
Product; o-Nitroaniline
Process: Ammonolysis of o-Nitrochlorobenzene
Process RWL Subcategory: D
Chemical Reaction:
H 0
N00C,H, Cl + NH (f>-xre>**\ ?
264 NH3 (excess) > N02C6VH2 + NV
Amm°nfa a-NltroanMIne + ammonium
o-nltrochlorobenzene chloride
Tiie manufacture of o-nitroaniline is similar to that of p-
nitroaniline, which is described in the next section. A
typical process flow diagram is shown in Figure 4-38.
The o-nitrochlorobenzene and ammonia enter the batch
reactor, and o-nitroaniline is formed. The excess ammonia
in the reaction mixture is distilled off the absorbers, from
which ammonia is recycled back to the reactor. The aqueous
stream from the distillation step goes to a washing
operation and proceeds to dehydration and refining
operations. Both the dehydration and the refining steps are
performed under vacuum and steam jets with barometric
condfinsers are generally used in pulling vacuum for these
operations. The refined o-nitroaniline may be used directly
or it may be further transformed into a flake.
The major water pollution sources of the process are waste
waters withdrawn from the scrubber in the ammonia-recovery
system, from the washing step, and the condensates from
barometric condensers. Process RWL's calculated from flow
measurements and analyses of the waste water streams are
indicated in the following tabulation. The analytical
results also indicate that waste streams may contain high
concentrations of nitrogen and chloride which may be
potentially hazardous to biological treatment processes.
PROCESS FLOW
liter/kkg 269,000
gal/M Ib 32,200
BODS RWL
mg/liter1 61
kg/kkg* 16
178
-------
FIGURE 4-38
ORTHO-NITROANILINE-AMMONOLYSIS OF ORTHONITROCHLOROBENZENE
RECYCLED NH
VD
AMMONIA
0-NITRO
CHLORUBENZENE
WASTEWATER
•0-NITROANILINE
WASTEWATER
WASTEWATER
-------
COD RWL
mg/literi 391
kg/Jdcg2 105
TOG RWL
mg/liter* 115
kg/kJcg* 30.9
*Raw waste concentrations are based on unit
weight of pollutant per unit volume of
process waste waters.
2Raw waste loadings are based on unit weight
of pollutant per 1000 unit weights of products.
180
-------
Product: p-Nitroaniline (PNA)
Process: Ammonolysis of p-Nitrochlorobenzene
Process RWL Subcategorv: D
Chemical Reactions:
H.o
N02C6HifC1 + NH3 (excess) > N02C6H4NH2 + NH/fC1
Ammonia
ammonium
p-nitroch1orobenzene p-nitroani1ine chloride
p-Nitroaniline is an important intermediate for dyes and
pigments and also for the preparation of numerous
antioxidants and antiozonants of the N-substituted p-
phenylenediamine type.
A typical process flow diagram for batchwise manufacturing
of p-nitroaniline is shown in Figure 4-39.
p-NitroaniJ.ine is manufactured by heating p-
nitrochlorobenzene with aqueous ammonia at 175°C under
pressure. A jacketed autoclave, provided with efficient
stirrers, is used as the reactor. Molten p-
nitrochlorobenzene is added to aqueous ammonia (28 percent)
and heated gradually. The temperature is increased over a
period of 3 hours to 175°C at a pressure of 530-580 psi, and
these latter conditions are maintained for 16 hours to
complete the reaction.
Some of the ammonia gas is then vented to an absorption
system. The excess ammonia in the reaction mixture is also
distilled off to absorbers, from which it is recycled back
to the reactor. The aqueous reaction mixture is passed
through a pressure filter and sent to wooden crystallizing
tubs, where the p-nitroaniline separates as a finely
divided, canary yellow crystalline mass. After cooling to
30 °C, the solid product (averaging 99 percent purity) is
removed by centrifuging. The centrate passes through an
elaborate system of catch boxes to cool it to room
temperature, and additional product settles out. This is
recovered periodically by siphoning the water from the catch
boxes.
The solid cake leaving the centrifuge is then passed through
drying and packaging steps. Dust collectors and scrubbers
181
-------
FIGURE 4-39
PARA-NITRO ANILINE-AMMONOLYSIS OF PARA - NITROCHLOROBENZENE
00
AMMONIA
P-NITRO-
CHLOROBENZENE
SLUDGE TO
LANDFILL
VENT AIR
WASTEWATER
i
WASTEWATER
5TALLIZATION
1
4STEWATER
L
-,
flORYING
| PACKAGI
I
FILTRATION « ;
AND
NG
• WAI
^
ER
WASTEWATER
P-NITROANILINE
SETTLER
T
WASTEWATER
-------
are used in the drying steps to remove the dust in the vent
gases.
The major pollution sources of this process are waste waters
withdrawn from scrubbers, filtration units, and the
crystallization unit. Process RWL's calculated from flow
measurements and analyses of the waste water streams
obtained in the survey period are shown in the following
tabulation. The analytical results also indicate that, in
addition to the parameters shown in the tabulation,
pollution parameters such as nitrogen, chloride and calcium
may be at levels potentially hazardous to biological
treatment processes.
PROCESS FLOW
liter/kkg 33,100
gal/M Ib 4,680
BODS RWL
mg/liter1 65
kg/kkg* 2.55
COD RWL
mg/literi 2,030
kg/kkg* 79.1
TOC RWL
mg/literi 570
kg/kjcg2 22.2
lRaw waste concentrations are based on unit
weight of pollutant per unit volume of
process waste waters.
2Raw waste loading are based on unit weight of
pollutant per 1000 unit weights of product.
These data are the basis for BPCTCA.
Continuous processes can also be employed for ammonolysis of
p-nitrochlorobenzene. In such a process, preheated aqueous
ammonia is forced through an inlet pipe to the bottom of the
vertical reaction cylinder, then passes upward through an
annular space, and overflows through a central outlet pipe
leading to a still, where excess ammonia is stripped off
before the product is crystallized. The space above the
overflow pipe provides a vapor space to absorb fluctuations
in the internal pressure. The lower part of the cylinder,
where the major part: of the reaction occurs, is provided
with packing and is constructed of stainless steel to
minimize corrosion. The operating pressure is about 1200
psi.
183
-------
Product: Pentachlorophenol
Process; Chlorination of Phenol
Process RWL Subcategorv: D
Chemical Reaction:
C6H5OH + 5C12 -» C6C15OH + 5HC1
Pentachlorophenol is widely used as a wood preservative,
especially in such applications as residential construction
where creosote would be undesirable. It is also used as a
fungicide in paint and adhesives, and in paper mills.
Although pentachlorophenol can be manufactured by continuous
processes, it is generally produced by batch reaction as in
the facility visited during the survey period. A simplified
process flow diagram for the production of pentachlorophenol
via the Chlorination of phenol is shown in Figure 4-40.
Phenol and chlorine are fed to the reactor where the
Chlorination reaction occurs. The product of the first step
of the reaction is trichlorophenol, which is further
chlorinated to form pentachlorophenol.
The product mixture leaving the second reactor is discharged
into a quench vessel, in which the gases are separated from
the molten product stream. The gases proceed to the HCl
absorber and caustic scrubber, while the liquid stream is
solidified in a flaker. The solidified pentachlorophenol is
then passed into a rotary kiln for glazing.
The major water pollution sources of this process are the
waste streams generated at the caustic scrubber, flaker, and
glazing units. Process RWL's calculated from flow
measurements and analyses of the samples obtained in the
survey period are shown in the following tabulation.
Sampling Period t1 Sampling Period 12
PROCESS FLOW
iiter/kkg 2,960 2,960
gal/M Ib 354 354
BODS RWL
mg/literi 330 306
184
-------
FIGURE 4-40
PENTACHLOROPHENOL- CHLORINATION OF PHENOL
PHENOL
00
CHLORINE
REACTOR
RECYCLE CHLORINE
T
WASTEWATER
1
QUENCH
VESSEL
A
0=
LLJ
OO
oc.
cs
OO
C_D QD
3= «C
O=
LU
OO
OO
ce
03
CO
l+MURIATIC
ACID
AIR
t
R >
FLAKER
1'^—
AIR
GLAZING
SYSTEM
CAUSTIC
SOLUTION
WASTEWATER
PENTACHLOROPHENOL
f
AIR
WASTEWATER
-------
kg/kkgz 0.975 0.906
COD itWL
mg/literi 5,740 6,020
kg/kkg* 17 17.9
TOC RVL
mg/liter* 768 781
kg/kkg* 2.27 2.31
waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2Raw waste loadings are based on unit weight of pollutant
per one thousand unit weight of product.
The analytical results also indicate that parameters such as
chloride, phenol, and sulfate may be at levels potentially
hazardous to biological treatment processes.
The demand for pentachlorophenol in the U.S. is
approximately 40 million pounds per year, of which 15
million pounds are used in mixtures with creosote.
Pentachlorophenol can also be made by caustic fusion of hex-
achlorobenzene, which is currently a cheapter route but
gives a product contaminated with Nad.
186
-------
Products; Fatty Acids and Primary Derivatives
Process RWL Subcategory: D
Fatty acids are organic acids characterized by a straight
chain carbon structure terminating in a single carboxyl
group. The carbon structure may contain only saturated
carbon atoms or may contain one or more double bonds.
In general, the saturated acids having 12 to 18 carbon atoms
are of major commercial concern. Their uses tend to reflect
their stability or lack of easy reactivity at any point
along the chain except at the carboxyl position. Saturated
acids, including those saturated by hydrogenation, comprise
about one-third of all fatty acids commercially produced.
Acids of reduced hydrogen content, having one or more double
bonds between carbon atoms along the chain, constitute the
other main fatty acid family of significant commercial
importance. The unsaturated acids of the ethylenic family
are made up of a number of separate series of the following
compositions:
CnH2n-202 (monoethenoic)
CnH2n-402! (diethenoic)
CnH2n-60.2 (triethenoic)
The chemical reactivity and utility of unsaturated fatty
acids in various polymeric or "drying" reactions is
determined in part by the number of double bonds along the
carbon chain. These double bonds also introduce different
properties arising from the location along the chain, i.e.
conjugated and nonconjugated fatty acids. A different
structure also results from a reversed positioning of those
parts of the molecule on either side of the double bond,
known as cis and trans isomerism.
To avoid confusion of terms, it is necessary to distinguish
between fatty acids as defined by the organic chemist and
fatty acids as commercially produced and sold. The term
"stearic acid" is an example of this confusion.
Here the commercial product name has priority, going back to
the splitting of tallow for the manufacture of hard, high-
melting candles, before individual acids of definite
composition had been isolated or identified.
Historically, commercial stearic acid has been a crystalline
combination of the chemist's palmitic and stearic acids in a
187
-------
55 to 45fc ratio, respectively, with some small percentage of
unsaturated acids. This ratio is that which naturally
occurred in the mixed acid derived from splitting tallow,
after most of the liquid acids were removed by the original
pressing method. The liquid acids so removed were known as
oleic acid, or red oil.
Other commercial acids have been identified by origin - for
instance, coconut fatty acid or cottonseed fatty acid - in
terms reflecting the characteristic ratio in which the
component acids exist when released from the glycerides of
these oils. Fractionation to separate or to enrich the
wanted acids, however, has made identification by origin
obsolete as a means of characterizing many of today's acids.
Blends and "cuts" are offered to meet particular market
demands, such as drying characteristics in paint films.
Composition expressed in terms of component acids as the
chemist defines them is now finding its way more and more
into product descriptions and specifications.
TaUle 4-3 lists 15 of the most important commercial fatty
acids, along with their composition in terms of specific
constituent acids.
In addition to the saturated and unsaturated acids, primary
derivatives based upon these acids modified by amination,
esterification, ozonation, and polymerization are considered
within the context of this study. Also, the processing
associated with the recovery and purification of by-product
glycerine is considered. The relation between glycerine and
fatty acid production will become apparent during subsequent
discussion. However, at this point it is noted that the
production of other products (such as soaps) from fatty
acids is not considered within the context of this
subcategory.
Raw materials for the production of fatty acids fall into
three groups:
1. Tall oil derived from Kraft papermaking.
2. Animal tallow and grease.
3. Vegetable oils and soap stocks.
As a raw material for fatty acid production, crude tall oil
ranks first in volume. Crude tall oil is a mixture of rosin
acids and free fatty acids (in addition to a large
percentage of water and impurities) and is a by-product of
kraft papermaking. Most of the crude tall oil is
fractionated, and the separated rosin acids and tall oil
fatty acids are sold directly to consumers after
188
-------
TABLE 4-3
DRAFT
oo
ID
Some Examples of Commercial Fatty Acids Showing Typical Percentage of Constituent Acids
Typical C-atoms
comme re i a 1
fatty acids Double bonds
Stearic acid (T.P. type)
Stearic acid (S.P. type)
Hi gh pa Imi t i c
Sol id fatty acid
(Hydrogenated tallow type)
Sol i d fatty acid
(Hydrogenated vegetable type)
Sol i d fatty acid
(Hydrogenated fish type)
Hi gh lauric aci d
(Di st i 1 led coconut)
Oleic acid (red oil)
(Disti 1 led)
Oleic acid
(Multiple distil led)
Animal fatty acid
(Disti 1 led)
Vegetable fatty acid
(Distilled cottonseed)
Vegetable fatty acid
(Di sti 1 led soybean
Vegetable fatty acid
(Fractionated soybean)
Ta 1 1 oil fatty ac id
Distilled linseed fatty acid
u
o o u o <->
.— — — .— t/i
0 — l- 1-
!_ >. Q_ D !_
O. Q_ 03 fD >-
ro ra o — i z
o o
68 10 12 lit
00 000
1
2
1
10
1 7 L>9 17
2
3
it
1
u
4-1
._
E
TO
Q-
16
0
50
51
75
35
29
35
9
7
5
25
2k
11
2
6
0
O -D O
~ !n 'c
ro u
-------
purification. The fatty acids derived directly from tall
oil can be used in the manufacture of primary derivatives
such as dimers, polyamides, nitriles, primary amines, di-
fatty tertiary amines, and fatty quatenary ammonium
chloride. The major constituents of tall oil fatty acid are
oleic acid and linolenic acid which contain two and three
double bonds respectively (see Table 4-3). It should be
noted that the production of tall oil fatty acid involves
only distillation of free acids and is simpler than the
processes used to manufacture fatty acids from animal and
vegetable sources.
There are four main types of animal fats: edible tallow,
inedible tallow, lard and inedible grease. Inedible tallow
and grease are important raw materials as a primary source
of stearic and oleic acids. These materials are supplied to
fatty acid manufacturers from meat packing an4 rendering
plants. It should be noted that fatty acid production is a
relatively small part of the tallow market, with i the major
end use of tallow being in the production of soap.
Coconut oil (obtained by crushing coconuts) is an important
vegetable raw material for fatty acid and fatty ester
production, because of its high C8, C10, and C12content.
Although soybean and cottonseed oil are produced in large
quantities, they are not often used for fatty acid
manufacture because of their high costs. However, by-
products from the refining of these oils for other end uses
are used in the manufacture of fatty acids. These by-
products are called "soap stocks" or "foots" and vary in
composition, depending on the refining process by which they
are produced.
It should be noted that fatty acids are present in animal
and vegetable sources as glycerides. Tall oil, which is not
a glyceride, is the only raw material which contains high
concentrations of free fatty acids. The three-pronged
glycerol linkage, typical of all fats, must be severed in
the production of all fatty acids derived from animal and
vegetable sources. The chemical reaction for this cleavage
involves the following hydrolysis:
0
II
R-C-O-CH,
CH
0
II
R,-C-0-
0
II
R2-C-0-CH2
Fat (triglyceride)
CH9-OH
i ^
CH -- OH
CH2--OH
Glyceri ne
R—COOH
4- R^COOH
R -COOH
Fatty acids
190
-------
The products of the reaction are crude glycerine and fatty
acids.
Depending upon the nature of the feedstock and the desired
end-product fatty acids, different combinations of the
following processing steps may be found in a fatty acid
plant:
1. Pretreatment for Purification of Feedstock
2. Saponification/Acidulation of Feed or Products
3. Hydrogenation of Feed or Product Acids
4. Hydrolysis of Feed (Fat Splitting)
5. Distillation of Product Acids
6. Distillation for Glycerine Recovery
7. Separation of Saturated and Unsaturated Acids
The following paragraphs briefly describe each of these
processing steps. A generalized process flow diagram
showing their interrelation is presented in Figure 4-41.
Pretreatment
Many of the impurities present in the feedstock will
decompose, volatilize, or contaminate the product acids and
must be removed. Water-soluble salts will deposit on
heating surfaces. Mineral acid will attack the fatty acid
upon heating and attack the equipment as well. Water-
washing and drying of feedstock containing these impurities
are essential.
Feedstock containing gums, proteinaceous material, calcium,
and iron soaps should also be acid-washed. Acid-washing is
generai-Ly performed in lead- or monel-lined tanks. A common
method is to treat a charge of melted fat at about 60°C with
2 to 4% sulfuric acid in a fairly concentrated (30 to 50%)
solution, with good agitation for about 1 hr. The charge is
then heated to 90°C with open steam. After settling, the
acid water is drawn off, and the charge is washed with water
to remove the mineral acid. Acid-washing breaks up calcium
and iron soaps that act as catalysts forming ketones or
remain as soap in still bottoms. Sulfuric acid removes
proteins and other organic impurities.
Acid-washing also removes impurities that hinder hydrolysis.
Bleaching with acid clays is effective in removing oxidized
acids and impurities that hinder splitting and/or
hydrogenation.
Saponification/Acidulation
191
-------
FIGURE 4-41
GENERALIZED PROCESS FLOW DIAGRAM ILLUSTRATING THE
MANUFACTURE OF FATTY ACIDS FROM GLYCERIDE FEEDSTOCKS
B
to
GLYCERIDE
FEEDSTOCK
SIGNIFICATION
ACIDULATION
HYDROGENATION
HYDROLYSIS
PRODUCT
ACIDS
DISTILLATION
OF ACIDS
(SATURATED
PRODUCT
ACID
UNSATURATED
PRODUCT
ACID
DISTILLATION
OF GLYCERINE
•GLYCERINE
PRODUCT
-------
In special cases where feedstock is the by-product "soap
stock" or "foots" produced in the caustic refining of
vegetable oils, the saponification of the feed followed by
acidulation is a convenient means of manufacturing fatty
acids. It has an advantage in the handling of raw refinery
foots because very little additional caustic soda is
required to complete the saponification prior to the acid
treatment. Completely saponified foots upon acidulation
yield raw material satisfactory for distillation. Although
more expensive than the other methods using water, it gives
practically 100X conversion and avoids the use of high
temperatures. The splitting of fatty acids from waxes and
sperm oil is done by complete saponification, using
anhydrous alkali, followed by steam distillation to remove
the high molecular weight alcohols. Subsequent splitting of
the soap is performed with sulfuric acid.
Hydroqenation
Hydrogenation is the process of adding hydrogen to materials
that are deficient in hydrogen, e.g. oleic acid, which
requires one molecule of hydrogen to form the C18 saturated
acid. Either the glyceride or the fatty acid can be
hydrogenated. The process is essentially the same, with the
exception that the acid must be processed in a corrosion-
resistant apparatus, usually stainless steel.
Refined oils, fats and fatty acids that have been properly
distilled are hydrogenated with little difficulty. Impure
materials or mixtures of fatty acids and neutral oil, such
as acidulated foots, are hydrogenated only after they have
been specially treated, and then usually with difficulty.
Hydrogen addition to the unsaturated groups occurs only by
means of a catalyst. Reduced nickel, the usual
hydrogenation catalyst, is made by reducing nickel salts,
i.e., formate, carbonate, or the aluminum nickel alloy.
Hydrogenation is done in both batch and continuous
processes. The batch process, which is older and not as
generally used today, uses a vessel that is equipped with a
top-entering agitator and a system for heating and cooling.
It is built to operate at pressures of from 25 to 250 psi
(in some instances up to 500 psi and higher). The nickel
catalyst is added to the pre-dried charge in amounts varying
from about 0.05 to 0.5S4. The vessel is purged several times
with hydrogen and then brought up to reaction temperature
with steam. Once reaction starts, however, it is
exothermic, and cooling is required to prevent overheating
of the catalyst and stock. The exothermic heat is
193
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significant with the absorption of 1 Ib-mole of hydrogen
releasing about 40,000 Btu, and requires substantial cooling
surface as well as good agitation. Good agitation is also
required to keep replenishing the reaction with hydrogen
gas. Eeactors in use today vary in size from those holding
a few pounds to large ones holding 50,000 Ibs.
Continuous methods for the hydrogenation of all classes of
chemicals have been developed in recent years, especially in
connection with petrochemicals and for petroleum processing
in general. The fat and fatty acid industries have been
much slower in developing and using continuous methods,
owing perhaps to the wide variety of products produced, the
relatively smaller volumes, and the need for modifying the
product by partial and selective hydrogen addition.
Hydrolysis
Hydrolysis or splitting is the process of reacting the fat
with water to form glycerine and fatty acid. A series of
three hydrolysis steps is required to obtain free acid and
free glycerine. It is believed that the reactions are
homogeneous taking place mainly in the fat phase, as the
solubility of water in fat is greater than the solubility of
fat in water.
It is necessary only to mix fat with water to cause some
hydrolysis, but the reaction is very slow. However, when
sulfuric acid is added to fat, the sulfonated products
formed increase the solubility of water in fat, and
hydrolysis takes place at a faster rate. Solubility is
further increased by the use of an alkaline catalyst, i.e.,
zinc oxide, magnesium hydroxide, or calcium oxide.
A major development in hydrolysis techniques was made by
Twitchell, who developed the sulfonic acid catalyst bearing
his name. Since the solubility of water in fat increases
very rapidly at high temperature, high-pressure autoclaves,
both of the batch and continuous type, have been developed.
Commercial fat splitting is carried out by several
processes, each of which has advantages and disadvantages.
The selection depends upon the type of raw material, size of
the operation, and the number of different kinds of raw
materials handled.
A. Twitchell Process
The Twitchell process, developed in 1890, is still used
to some extent in the United States. It is carried out
194
-------
in a lead- or monel-lined tank at atmospheric pressure.
The charge consists of fat mixed with about 50 wt.X
water, 1% sulfonic acid catalyst, and 0.5JI sulfuric
acid. The mixture is then boiled with open steam for 16
to 24 hrs, allowed to settle, and the sweet water is
drawn off and replaced with fresh water. The boiling is
continued until a split of about 95% is reached. The
overall split depends upon the glycerol concentration of
the sweet water.
By countercurrent use of water, it is possible to obtain
high splits and high concentrations of sweet water,
usually 10 to 15X. The advantages of the Twitchell
operation are its relatively simple equipment and the
use of low temperatures. Low-temperature operation is
highly desirable for splitting stocks containing
multiple unsaturation. Disadvantages are the length of
time required, high steam consumption, and poisoning of
the catalyst, which necessitate the pretreatment of most
stocks, especially the lower grade variety.
B. Batch Autoclave
Batch autoclaving is * a very old method, which, as
originally developed, used a closed cylindrical pressure
vessel with agitation provided by open-steam injection
to a continuous vent. Typical temperatures are about
185°C, equal to about 150 psi. About 2% lime, zinc
oxide, and so forth are used. The amount of water is
about 50 wt.% of the fat. The degree of split reaches
an equilibrium at about 90*. To obtain a higher split,
the glycerine water must be replaced with fresh water.
This catalytic autoclave process is suitable for all
types of fats and has the advantage over the Twitchell
process of a shorter reaction period and the production
of lighter colored fatty acid because of the absence of
air. A more recent development in autoclave splitting
is the use of higher temperatures and higher pressures
requiring no catalyst. This process is usually carried
out using mechanical agitation, with the temperature
held at about 238°C under a pressure of 450 psi.
Splitting is rapid, and there is no catalyst to remove.
Its disadvantage is the effect of high temperature on
stocks having a high degree of unsaturation.
C. Continuous Countercurrent Splitting
Over the past 30 years, several companies have designed
and built successful continuous hydrolyzers which have
195
-------
replaced the older methods. Fat enters near the base of
the hydrolyzer and passes upward through the column and
exits through a pipe near the top. Steam from the high-
pressure steam boiler, at 750 psi, is injected at two
locations, the top addition into a water-distributing
tray and the lower addition through a sparger pipe near
the fat-water interface.
The fat rises slowly through the column in a continuous
phase while the water drips through it, constantly re-
placing the glycerine-laden water that is in solution in
the fat. At the bottom of the tower, the glycerine
water collects and is removed continuously to maintain a
constant interface level near the base of the tower.
The fatty acid leaves the top of the tower through a
pressure control valve set to maintain about 720 psi,
sufficiently high to prevent vaporization of water at
the required operating temperature, usually about 250 to
260°C.
The fat must be under pressure for about 2 hrs to reach
a split of 56 to 99%. The reaction time required may
vary, depending upon the type of fat and quantity of
water used. It is usual practice to remove sweet water
with a concentration between 12 to 20% glycerine.
Continuous splitting has the advantage of yielding high
splits and more concentrated glycerine solutions than
any other process. It has a high capacity and short
reaction time. It requires less room, less process
inventory, and less labor. It does, however, restrict
flexibility in changing stocks. The high temperatures,
as mentioned above, have the advantage of speeding up
tne hydrolysis reaction; however, it has a real
disadvantage when handling highly unsaturated fat, such
as fish oil, because these oils tend to polymerize.
Recovery and Purification of Glycerine
The dilute (10-20 wt.X) glycerine solution ("sweet water")
may be concentrated by taking water overhead in an
evaporator or distillation column. In most operations, non-
contact steam is used to drive off the water to an
approximate 8OX glycerine concentration. The noncontact
steam may be condensed and used in the hydrolysis reactor.
The separated water vapor and some glycerine are normally
condensed in a barometric condenser and discharged.
Additional treatment steps for purification of glycerine
196
-------
water may include filtration, ion exchange, and activated
carbon adsorption.
Distillation
Distillation as a means of purifying fatty acids has been in
use for the better part of a century. It is an economical
and successful method of producing high-purity fatty acids.
It is beset with many problems because fatty acids have high
boiling points and decompose when held at elevated
temperatures. The early distillers soon discovered that
processing temperatures must be held at about 250°C maximum
to limit decomposition. At higher temperatures, fatty acids
first lose water, forming anhydrides, and later, under
continued heating, break down into ketones and hydrocarbons.
Unsaturated fatty acids polymerize, forming dimers, trimers,
and so forth.
The early stills were operated at atmospheric pressure and
large quantities of injected steam were used to maintain the
temperature at 250°C. As better equipment became available,
the stills were operated at lower and lower pressures until
today most fatty acid stills operate at pressures of between
5 and 50 mm Hg abs. At low pressures, fatty acids will
distill without injected steam, but it is usually desirable
to use some injected steam because even a small amount will
aid in preventing the formation of anhydrides. When stills
are operated at pressures lower than the vapor pressure of
the available cooling water, it is necessary to provide a
steam compressor in addition to the ordinary air pumps to
maintain desired operating pressures.
Fatty acid stills now in general use may be classified into
three general types: 1) those for semicontinuous batch
operation; 2) those for continuous simple distillation; and
3) those for continuous fractional distillation. If only a
decolorizing step is necessary (one that removes the
unhydrolyzed oil, polymers, and high-boiling color bodies),
a simple distillation will produce satisfactory results. If
considerable amounts of color bodies (low-boiling
unsaponifiable matter and compounds that cause color
reversion) are present, some means of fractionally
concentrating these "low boilers", either by fractional
distillation or fractional condensation, is required. If
the component acids must be separated, an efficient
fractionating still is necessary.
197
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Separation Processes
Separation of tallow fatty acids into solid (saturated) and
liquid (unsaturated) components cannot be accomplished by
the fractionation methods previously described because major
components have the same chain length and an insignificant
difference in molecular weight. Two major separation
processes have achieved commercial significance in the
separation of solid saturated acids from liquid unsaturated
acids, namely, the panning and pressing method and solvent
crystallization.
Tne panning and pressing process at one time accounted for a
major portion of the total production of stearic and oleic
acids. The idea of pressing liquid fatty acids from solid
fatty acids probably occurred from observing the production
of lard oil. In fact, equipment used for the pressing of
grease to yield lard oil was initially used for the
separation of fatty acids. This method is used for the
separation of animal fatty acids to produce commercial
stearic and oleic acids. Simply, this method involves the
crystallization of solid or saturated fatty acids in a
solvent of liquid or unsaturated fatty acids. Consequently,
the solid (saturated) fatty acids must exhibit a reasonably
good crystal formation so that the liquid acids may be
easily and efficiently expressed.
In the production of commercial stearic acid, the optimum
crystal structure is attained when the saturated acids of
the fatty acid mixture have a composition of 55% palmitic
acid and 45% stearic acid. Limited variation in this ratio
may be tolerated in actual practice, but the variation in
normal animal fats is sufficient so that blending is
necessary to secure a proper crystalline structure. Fatty
acid mixtures of a noncrystalline structure may be partially
separated by the pressing method.
In the panning and pressing operation, properly prepared
melted fatty acids are cascaded into rectangular aluminum
trays, which are stacked in racks in cold-storage rooms.
Cooling takes place very slowly to assure the formation of
large and well-defined crystals. Cooling by mechanical
refrigeration to a final temperature of 180°C is attained in
a cold-storage room in about 6 to 8 hrs. The solidified
cakes of fatty acids are removed from the trays, wrapped in
burlap or cotton cloths, and stacked in vertical hydraulic
presses. Metal sheet separators are placed between every
two layers of wrapped cakes to serve as stabilizers to
conduct the expressed oleic acid to a trough at the edge of
the press. Pressure is very slowly applied to the stack of
198
-------
cakes until a maximum of approximately 3,000 psi is
attained. The expressed oleic acid amounts to about 50 to
6034 of the original fatty acids. Depending upon the
temperature of the cakes of fatty acid during pressing, the
titer of the oleic acid will range from 6 to 10°C.
The pressed cake, now referred to as "cold pressed cake", is
melted, again cascaded into racks of aluminum trays in an
open room, and allowed to solidify at room temperature. The
solidified cake is placed in hair mat slings suspended
between steam-heated hollow metal plates in a horizontal ram
press. Application of pressure and heat removes most of the
oleic acid along with a small portion of the solid acids,
resulting in a mixture of fatty acids known as "hot press
oil". The pressed cake from this "hot pressing operation"
is called "double-pressed" stearic acid. It contains about
5 to 834 oleic acid and has a titer of approximately 54 to
55°C. In much the same manner "triple-pressed" acid is
produced with the additional production of hot press oil.
Triple-pressed stearic acid contains from 1 to 3% oleic acid
and has a titer of approximately 55 to 56°C. The hot press
oil has a composition of saturated and unsaturated acids
similar to the feedstock and is therefore mixed with the
incoming fatty acid feed. As a result, about 40X of the
fatty acids in this process is being recycled.
The panning and pressing method is gradually being replaced
by the newer solvent methods, as has countercurrent
extraction by immiscible solvents.
Solvent processes utilizing a liquid-liquid extraction
method have been proposed, but the solubility of mixed fatty
acids in solvents results in an inefficient separation.
This has limited the commercial use of these methods.
Separation methods involving the crystallization of one-
componer^t fatty acids from a solvent solution of a mixture
of fatty acids eliminate, to a large extent, the effect of
mutual solubility. Solvent crystallization methods may be
applied to the separation of most fatty acid mixtures,
provided the component acids can be selectively removed in a
solid state, from a solvent solution of the mixture.
Of the many solvent crystallization separation methods
proposed, the Emersol Process is most commonly employed.
This process involves the controlled crystallization of
fatty acids from a polar solvent to achieve a separation of
solid fatty acids from liquid fatty acids. Separation of
saturated acids or of triglycerides may also be
accomplished. One of the best illustrations of the
199
-------
application of this process is in the separation of animal
fatty acids to yield commercial stearic acid and oleic acid.
Animal fatty acids are dissolved in 90% methanol to yield a
25 to 30% concentration. The methanol solution of the fatty
acids is pumped continuously to a multitubular crystallizer
fitted with agitator scraper blades and cooled to about
-15°C. Cooling 4-s accomplished by circulating refrigerated
methanol through the jackets of the crystallizer tubes.
During chilling the solid fatty acids crystallize from the
solvent solution to form a slurry that is fed to a rotary
vacuum filter. The solid acids filter to form a cake that
is continuously washed with fresh 90% methanol and then
discharged from the filter. This filter cake containing ap-
proximately 40 to 6058 methanol is melted and pumped to a
solvent recovery still in which the solvent is removed from
the fatty acids and returned to the system. The solid acids
are discharged from the still ready for finishing and
packaging operations into commercial stearic acid.
The filtrate containing the liquid acids is passed through a
heat exchanger to a solvent recovery still. The discharged
liquid acids from the still are ready for finishing and
packaging into commercial oleic acid. Reported capacities
of the Emersol units range from 2000 to 5000 Ibs of fatty
acids per hour. At present, there are seven units in
operation in the United States, Great Britain, Holland, and
Australia.
Certain other separation methods, although not yet
commercial, have interesting possibilities. A solvent
crystallization process for separating tallow fatty acids
using hexane as a solvent has been employed. Much has been
published on the separation of fatty acid mixtures by use of
urea or thiourea complexes. Urea or thiourea adducts or
complexes of fatty acids have varying degrees of stability,
depending on the carbon chain length and configuration of
the molecule. This difference in adduct stability is the
basis for obtaining a separation of the fatty acids.
Recovery of Fatty Acids from Tall Oil
When nonglyceride feedstocks such as tall oil are used, a
different process from that shown in Figure 4-41 must be
used.
In the production of tall oil fatty acids and rosin by
fractional distillation, crude tall oil is passed through a
vaporizer into a fractionating column where the volatile
rosin and fatty acids are separated from higher-boiling and
200
-------
nonvolatile impurities, which are drawn off as pitch. The
vapor enters the fractionation column and is separated into
three fractions: 1) rosin that is taken off at the bottom
of the column, 2) a fatty acid containing from 1 to 5% rosin
near the top of the column, and 3) a heads fraction
overhead, containing a high percentage of low-boiling fatty
acids (mainly palmitic), unsaponifiables, and color bodies.
The fatty acid fraction is then passed into a third column
where it is further stripped of rosin, unsaponifiables, and
color and odor bodies to yield a product with a rosin
content of 0.3 to 2.031 and unsaponifiables content of 0.3 to
1.5*. The fraction containing 25 to 35X rosin, taken off at
the bottom of this column, is either sold as such or
refractionated. By taking fatty acids off at the second
column or at various points on the third column, the rosin
content of the fatty acids can be varied.
The fractionation of tall oil presents a number of problems.
Both rhe fatty acids and the rosin have low vapor pressures
and are subject to decomposition on heating. Either very
high vacuum or vacuum with the addition of superheated steam
is needed to keep the temperature low enough to prevent
damage to the products. Overheating must be prevented
during vaporization by creating high flow velocities in
heaters and vaporizers, and entrainment must also be
prevented. The equipment is, therefore, specifically
designed for the purpose. Various types of fractionating
trays, grid trays, sieve trays, and bubble-cap trays are
used; all of them have certain advantages and disadvantages
and unless they are carefully chosen and designed for the
purpose, will fail to produce the desired results.
Different operating schemes are used by the various
producers, employing single and multiple tower system. A
two-tower system can produce excellent results by
refractionating the fatty acids. This raises the operating
cost but the investment cost for the plant is lower.
For the purposes of this study, the previously described
unit operations and chemical conversions are defined to be
the basic steps necessary to produce fatty acids. Field
sampling was used to establish raw waste loads for plants
encompassing these steps. Because of the batch or semi-
continuous nature of the operations, it was not possible to
break out the total RWL according to individual step
sources. Rather, combined waste streams from the acid
production areas were sampled in most cases. A total of 6
plants were sampled. Table 4-4 indicates the specific
operations relating to acid and derivatives production.
Table 4-5 summarizes the RWL data related to acid production
201
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TABLE 4-4
CHEMICAL CONVERSIONS AND UNIT OPERATIONS CONTRIBUTING TO PROCESS RAW WASTE LOADS FOR THE MANUFACTURE OF FATTY ACIDS AND
PRIMARY DERIVATIVES (BASED ON PLANTS SURVEYED)
Plant 1
Acid Production
1 .
2.
3.
4.
5.
>
)
1 .
2.
3.
'
Acid Washing
High Pressure
Fat Spl i tting
Glycerine Recovery
and Purification
Solvent Separation
of Fatty Acids
Hydrogenat ion of
Fatty Acids
Derivatives
Dimerizat ion £•.
Trimerizat ion
Ozonat i on
Esterif ication
Amrn i na t i o n
Plant 2
Acid Production
1 . Pretreat. by Fi It.
and Acid Wash
2. Hydrogenat ion
of Tal low
3. Hydrolysis by
Twi tchel I Proc.
k. Glycerine Recovery
5. Distil lation of
Fatty Acids
6. Separation of
Acids by Pressing
Plant 3
Acid Production
1 .
2.
3.
k.
5.
6.
(b)
1.
2.
Saponi f ication
Acidulation
Hydrogenat ion
Fat Spl itting
Glycerine
Recovery (b)
Disti 1 lation
Wastewater from
Glycerine Re-
covery Sampled
Separately.
Derivatives
Esterif ication (c)
Ammi nation (c)
Plant k
Acid Production
1 . Pretreat. by Fi It.
2. Hydrogenat ion
3. Fat Splitting
4. Glycerine
Recovery
5. Distillation
Derivatives
1 . Esteri f ication
Plant 5 (d)
Acid Production
1 .
2.
3.
4.
1 .
2.
(d)
Hydrogenat ion
Fat Splitting
Glyceri de
Recovery
Distil lat ion
Deri vat i ves
Esteri f ication
Ammi nation
Production Units
for Acids &
Plant 6 (e)
Acid Production
1. Distillation from
Tall Oi 1
Derivatives
1 . Dimerizat ion &
Trimerizat ion
2. Ammi nation
(e) Only production units
for derivatives
were sampled.
Derivatives could
not be sampled
separate! y.
Wastewater included with
acid product.
(c) Esters & Ammi ne
Sampled Separately
-------
for 5 plants, and presents an arithmetic average for these
operations. It is noted that the RWL data presented in
Table 4-5 are based on samples taken after gravity
separation of fatty acids from the waste water. It is
common practice to recycle the skimmed material back to the
acid pretreatment section of the plant for recovery.
Table 4-6 summarizes the raw waste loads calculated from
production of primary derivatives. The data shown relate to
groups of processes in operation during the sampling
program. Primary derivative products include esters,
amines, nitriles, dimers and trimers, polyamides, and fatty
quaternary ammonium chloride. An average RWL value for
these processing operations is provided in Table 4-6.
The average values shown in Tables 4-5 and 4-6 are the basis
for BPCTCA,
203
-------
TABLE 4-5
PROCESS RWL ASSOCIATED WITH MANUFACTURE OF FATTY ACIDS
(ALL RWL BASED ON SAMPLES TAKEN AFTER GRAVITY SKIMMING
FREE FATTY ACIDS FROM WASTEWATER)
Flow BOD COD TOG
(lit./kkg) (kg/kkg) (kg/kkg) (kg/kkg)
Plant 1 (1 day) 10,300 (a) 12.7 44.3 4.89
(1 day) 10,300 (a) 18.5 52.5 10.3
Plant 2 (1 day) 63,900 12.8 23.6 4.41
Plant 3 (1 day) 3,700 (b) 11.7 37.3 10.6
(1 day) 45,500 (c) 14.6 41.6 14.3
Plant 4 (1 day) 65,900 5.8 21.5 1.2
Plant 5 (1 day) 12,100 (d) 15.6 42.4 13.6
(1 day) 12,100 (d) 37.5 53.2 18.9
Average 28,000 16.1 39.6 9.8
(a) RWL includes wastewater from dimerization
(b) RWL does not include wastewater from glycerine recovery
(c) RWL based only on glycerine recovery (i.e., based on glycerine)
(d) RWL includes small contribution from derivatives
204
-------
TABLE 4-6
PROCESS RWL ASSOCIATED WITH MANUFACTURE OF PRIMARY DERIVATIVES
FROM FATTY ACIDS (NOTE RWL BASED ON SAMPLES TAKEN AFTER GRAVITY
SKIMMING FREE OIL INDICATED BY ASTERISK)
Plant 1* (1 day)
(1 day)
Plant 3
Esters (1 day)
Amines (1 day)
Plant 4* (1 day)
Plant 6* (1 day)
Flow BOD COD TOC
(lit./kkg) (kg/kkg) (kg/kkg) kg/kkg)
Average 6,400 18.0 27.9 8.47
(Exclude Plant 3)
4,590
4,590
127.0001
18.8002
8,920
5,700
16.5
17.0
26,500
495
28.6
9.82
32.6
41.3
54,700
1,070
14.7
23.0
9.75
14.7
13,600
245
5.7
3.73
Sample taken prior to methanol recovery
2
Sample from blowdown on recirculating system
205
-------
Product; Jonone and Methylionone
Process; Condensation and Cyclization of Citral
Process RWL Subcategory: D
Chemical Reactions;
Citral + Acetone NaOH > pseudo-lonone
pseudo-lonone H2S04 >e<- lonone + (3-lonone
lonones and methylionones are used in perfumery and flavors;
the beta ionone isomer is an intermediate in the manufacture
of vitamin A.
/
The production of ionones and methylionones involves two
steps. First, the pseudo-ionone is prepared by the
condensation of citral obtained from lemongrass oil. The
condensation reaction uses either acetone or methyl ethyl
ketone to produce pseudo-ionone or pseudo-methylionone.
Then these pseudo-ionones are cyclized with an acid
catalyst. Commercial ionones are generally mixtures of the
alpha and beta isomer, with one form predominating, although
separations are sometimes made through bisulfite compounds.
A typical process flow diagram for producing
ionone/methylionone is shown in Figure 4-42. Citral,
acetone/methyl ethyl ketone, sodium hydroxide, and organic
solvent are put into the first batch reactor. The solvent
from tnis reaction step is recycled, and the product vapors
are condensed and stored in a receiver. The crude product
from the receiver is then distilled to remove the heavy-end
residues and washed with caustic solution to obtain
pseudo-ionone (or pseudo-methylionone).
These materials are fed into the second reactor, where
cyclization is accomplished via a carbonium ion reaction
with H3P04, H2SO4;, or BF3 as catalyst. The reaction
products proceed through a series of washing tanks, where
the products are quenched with sulfuric acid and then washed
by water, caustic solution,, and acid solution.
After the washing steps, the product mixture is discharged
into a series of distillation columns, where the organic
solvent and heavy end residue are recovered and withdrawn
from the main product stream. The product vapor leaving the
206
-------
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last distillation column is condensed and sent to a liquid-
liquid separator for removal of water.
Trie major water pollution sources of this process are waste
waters from the various washing steps arid from periodic
reactor washings. During the sampling visit, pseudo-ionone
was being produced; hence the waste water samples obtained
at the facility reflect ionone production RWL. However, the
RWL of methyl-ionone is believed to be of the same order of
magnitude as that of ionone. Process RWL's calculated from
flow measurements and the analyses of the waste water
streams are indicated in the following tabulation:
PROCESS FLOW
liter /Jckg 9,370
gal/M Ib 1,120
BODS RWL
mg/literi 2,600
24
COD RWL
mg/liter1 10,000
kg/kkg2 98
TOC RWL
mg/liter * 3,600
34
»Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste
waters.
2Raw waste loadings are based on unit weight of pol-
lutant per 1,000 unit weights of product.
The analytical results also indicate that, in addition to
the parameters shown in the tabulation, pollution parameters
such as pH, sulfate, oil, and chloride may be at levels
potentially hazardous to biological treatment processes.
These data, shown above, were used to determine BPCTCA. The
wastes from this plant are discharged to a municipal
treatment plant.
208
-------
Product; Methyl Salicylate
Process: Esterification of Salicylic Acid with Methanol
Process RWL Subcategory: D
Chemical Reactions:
Methyl salicylate, the methyl ester of salicylic acid, also
known as "oil of wintergreen" is used as a flavoring
compound in mouthwash and certain food products. A diagram
of process is shown in Figure 4-43.
COOH + CH3OH _* Cg
salicylic acid methanol methyl salicylate
Raw waste loads for the production of methyl salicylate are
indicated in the following tabulation:
PROCESS FLOW
liter/kkg 1,735
BODS RWL
kg/kkg 22.0
COD RWL
kg/kkg 93.9
TOG RWL
Jcg/kkg 37.9
209
-------
FIGURE 4-43
METHYL SALICYLATE ESTERIFICATION OF SALICYLIC ACID
SALICYLIC ACID
METHANON
ESTERFICATION
SYSTEM
METHYL
SALICYLATE
210
-------
Products: Miscellaneous Batch Chemicals
Intermediates
Dyes
Rubber Chemicals
Process: Numerous Batch Processes (Batch Chemicals Complex)
Process RWL Subcategory: D
The RWL data presented and discussed in the following
paragraphs were obtained by sampling the total effluent from
a large chemical plant. This plant manufactures thousands
of chemicals within the five general classifications
indicated above. In this case, it was impossible to sample
each of the process operations on an individual basis.
Daily 24-hour composite samples were taken over a period of
9 days, followed by three 5-day composite samples over the
next 15 days. The measured flows and concentrations were
put on a production basis by means of a weekly production
activity report supplied by the manufacturer. The RWL data
obtained in this manner are summarized in Table 4-7.
The RWL data shown in Table 4-7 represent the total raw
waste from the plant. Examination of the data based on the
nine consecutive 24-hour composite samples indicates
significant variation. For example, the calculated mean for
BOD is 20.4 kg/kkg of product with high and low values of
27.4 and 11.9 during the nine-day period.
It is significant to note that the three 5-day composite
samples show approximately the same range of variability.
The calculated average BOD raw waste load for the three
periods is 24.1 kg/kkg, with high and low values of 35.8 and
14.1 respectively. BPCTCA raw waste loads for the batch
chemicals complex was based upon the 5 day composite
samples.
This type of variation may be caused principally by the fact
that in this type of chemical plant it is difficult to
relate production data to the exact sampling periods, and
consequently, calculated ratios will always have this type
of error present.
Production at a batch chemical complex involves the startup
and shutdown of thousands of discrete batch processing
operations on a day-today basis. Although the plant
maintains a materials inventory, this is usually updated
only on a monthly basis. In this particular case, the
manufacturers expended considerable effort to provide weekly
production figures based on changes in the materials
inventory.
211
-------
Table 4-7
RWL Data for Batch Chemical Complex
Sample Period Flow BOD COD TOC
L/kkg (kg/kkg) (kg/kkg) (kg/kkg)
2k hr. composite
n n
Average
5-day composite
n M
M n
Average
65,300
74,800
90,100
89,300
71,300
113,000
68,800
70,400
78,700
80,100
70,600
65,500
100,000
78,700
19.6
16.5
27.0
27.4
23.8
27.4
11.9
13.0
16.9
2CK4"
22.4
14.1
35.8
24.1
63.5
68.4
90.1
96.4
83.9
99.4
55,3
60.4
77.0
77.2
80.9
76.6
144.
100.5
17.0
19.5
23.4
29.9
22.1
29.2
M. 9
23.9
23.6
22.9
27.1
27.1
40.1
3K4
212
-------
Products: Citronellol and Geraniol
Process: Distillation of Citronella Oil
Process RWL Subcategory: D
Chemical Structure;
(CH3)2 C = CH-(CH2)2-CH-CH2CH2OH
citronellol
>2~C = CH(CH2)2-C = CHCH,OH
I *
CH
Geraniol
Citronellol and Geraniol are used as odorants in perfumery.
Natural geraniol is produced by the distillation of
citronella oil. Citronellol is made by limited
hydrogenation of geraniol. Figure 4-44 is a process flow
diagram of geraniol and Citronellol production. Citronella
oil, the raw material, is vacuum distilled to separate
Citronellol. The remaining citronella oil components
undergo a three-stage potassium hydroxide washing prior to
vacuum steam distillation followed by vacuum distillation.
In this step, geraniol and Citronellol are recovered; the
geraniol fraction is washed with a caustic solution and then
water. The geraniol terpene fraction then undergoes
boration and washing prior to being rerun through the vacuum
distillation step.
As shown in Figure 4-44, the major wastestreams from the
process are vacuum jet condensates and waste water from
product washes. The following tabulation summarizes the RWL
calculated for the process:
Flow
liters/kkg 10,000
gal/1000 Ib 1,199
BODS
mg/1 5,810
kg/kkg 58.1
COD
mg/1 11,100
213
-------
DISTILLATION
COLUMN
O ^
* m z MM
ipr
DISTILLATION
COLUMN
r
DISTILLATION
COLUMN
•HI
•I — 1 C3 CT3
:\^ m —
=o
sr
r=i
FU"
m 1
o
—«
70
O
z
z
o
O
m
71
> -n
? 5
o
5
o
z
o
^
D
O
z
-------
kg/kkg 111
TOC
mg/1 3,770
kg/kkg 37.7
The foregoing values used to define BPCTCA.
215
-------
Product; Plasticizers
Process: Condensation of Phthalic Anhydride
Process RWL Subcategory: D
Plasticizers are organic chemicals that are added to
synthetic resins to improve workability during fabrication,
to modify the natural properties of these resins, and to
develop new improved properties not present in the original
resins. This type of chemical is manufactured by liquid-
phase batch reactions.
A generalized process flow diagram is shown in Figure U-45,
while tne overall chemical reaction is given below:
2ROH
phthalic anhydride alcohol phthalate
Feed materials, an alcohol and an anhydride, along with an
acid catalyst, are fed into a reactor. The esterification
is carried out at a pressure of about 10 psig and at
temperatures ranging from 35 - 180°C, for six to 20 hours,
depending on the feed and the desired product. The reactor
effluent is either sent directly to a wash tank or passed
through a filter press to remove solids, depending on
whether activated charcoal or a catalyst neutralizer has
been added to the reactor.
Caustic soda (or soda ash) is used in the wash tank to
remove unreacted acid and anhydride. Waste water from the
washing is sent to a series of settling tanks before being
discharged to the sewer. Oil removed in the settling tanks
is recycled back to the reactor.
The plasticizer stream from the wash tank flows to a
stripper, where any remaining alcohol is taken overhead and
recycled to the batch reactor. The main stream from the
stripper is further polished by an activated carbon filter
to obtain 99.5* percent purity plasticizer.
RWL data obtained from a plant survey are summarized in the
following tabulation. Since the plant surveyed is designed
216
-------
FIGURE 4-45
PLASTICIZERS—CONDENSATION OF PHTHALIC ANHYDRIDE
RECYCLE ALCOHOL
ALCOHOL
ANHYDRIDE
N)
I
WASTEWATER
FILTER
I
NEUTRAL-
IZATION
ACTIVATED
CARBON
SETTLING
TANK
-*WASTEWATER
PRODUCT
-------
strictly for manufacturing of one plasticizer (diethyl
phtiialate) , it requires less frequent reactor clean-up.
PROCESS FLOW
liter/kkg 653
gal/M Ibs 78.3
BODS RWL
rag/liter* 82,600
kg/kkg2 53.9
COD RWL
mg/literi 127,000
kg/kkg2 82.6
TOG RWL
mg/literi 51,200
kg/kkgz 33.4
iRaw waste concentration are based on unit
weight of pollutant per unit volume of
process waste waters.
2Raw waste loadings are based on unit weight
of pollutant per 1000 unit weights of product.
These data were used as the basis for BPCTCA.
218
-------
Product: Dyes and Dye Intermediates
Process: Batch Chemical Reactions
Process RWL Subcategory: D
Dyes may be defined as intensely colored substances which,
when applied to a substrate, impart color to this substrate
by a process which, at least temporarily, destroys any
crystal structure of the colored substances. The dyes are
retained in the substrate by adsorption, solution, and
mechanical retention, or by ionic or covalent chemical
bonds. Pigments, on the other hand, are usually applied in
vehicles (although the substrates themselves may serve as
vehicles, e.g., in the mass coloration of polymeric
materials), and retain, to some degree, their crystal or
particulate structure.
The color of a dye is due to electronic transitions between
molecular orbitals of the molecule, the probability of these
transitions determining the intensity of the color. The
energy differences between the orbitals determine whether
the "color" falls in the visible range of the electro-
magnetic spectrum and, if it does, the precise shade or hue.
Only organic molecules of considerable complexity,
containing extensive conjugated systems and polar or
semipolar substituents, are useful as dyes.
Much of the complexity of present-day dye technology arises
from the great diversity of materials to be dyed, such as
foods, drugs, cosmetics, waxes, greases, solvents, plastics,
rubber, photographic film, leather, fur, paper, and,
primarily, textiles. In the textile field, the introduction
of synthetic fibers, such as cellulose acetate, nylon,
polyester, acrylics, cellulose triacetate, and
polypropylene, as well as the more stringent fastness re-
quirements and the continuous-dyeing techniques, have
presented the dye manufacturer and user with new problems.
Tnese problems cannot be separated from one another. For
example, the new polyester fibers are sometimes dyed by a
continuous heat-treatment process requiring new dyes with a
new fastness property, sublimation fastness and a special
physical form. Dispersed dyes, for instance, are more
hydropnobic than those used previously for cellulose
acetate. They must also be nonvolatile (i.e. must not
sublime off the fiber during the heat treatment) and must
have a physical form, either powder or paste, which gives
rapid and stable dispersions in the dye bath.
219
-------
Dye intermediates are derived from a wide variety of
aromatic organic compounds, such as benzene, naphthalene,
anthracene/ higher polycyclic derivatives, and
heterocyclics. The United States Tariff commission lists
some 230 compounds under the heading "cyclic intermediates",
of which more than 210 are used in the dye industry. Many
of the large-volume intermediates have a principal use
outside the dye industry. For example, about 60 percent of
the aniline produced is used in the rubber industry, and
practically the entire phenol and phthalic anhydride
production is consumed by the plastics industry.
Originally, however, all three of these materials were
exclusively dye intermediates.
The dyes themselves are usually much more complicated than
the intermediates from which they are derived. Some dyes
are mixtures, while others (such as aniline and sulfur
colors) are still unknown structures. Therefore, systematic
chemical names are rarely used. Almost all dyes also have a
multiplicity of trade names in addition to their common
names. Despite the diversity of trade names, a certain
amount of rationality can be found in these names. Thus,
most may be considered to be divided into three parts, as in
the example of Cibacete/Brilliant Blue/BG. The first part
usually gives the particular dyeing class, and, from this
trade name, we learn that the dye is a disperse dye intended
for application on acetate. Cibanone would be the same
manufacture's designation for a vat dye of high fastness.
The second part of the name is obviously the color, and the
third part (BG in this case) refers to the shade. Often the
letters subdivide the numerous reds, oranges, blues, and
greens into bluish (B), greenish (G), yellowish (Y) (or G
for the German "gelb"), and reddish (R) shades. A number in
front of these letters indicates their depth, as in the name
"Crystal Violet 6B". Other letters show other properties.
Thus, K stands for cold dyeing (the German "kalt"), L for
lightfastness, M for new, CF for copper free (as in the case
of goods to be vulcanized), A for acetate left unstained, W
for washfastness, and S for sublimation fastness. Strength
and physical form are designated at times by such terms as
Cone, (concentrated), Dbl. Pst. (double-strength paste),
Pdr. (powder) , etc.
Dyes have been classified by a wide variety of schemes.
Classes based on usage and application are useful to the
dyer and also to the dye manufacturer who must supply the
demands. However, this type of classification results in
groups containing a great diversity of chemical structures.
Table 4-8 is arranged according to a usage classification
and indicates briefly the major substrates, method of
220
-------
Table 4-8
Azoi c dyes and com-
ponents (1ngrai n)
Di sparse
• Mordant
Major jubstrate^
2
Wool, silk, nylon, and
polyacryIi c
Cotton ' (also silk, wool, and
fur) and blacks on acetate and
polyester
Cotton ' leather, paper, wool,
silk, polyacrylics, and other
synthet ics
Cotton, ' paper, and nylon
CelIulose acetate, tr iacetate ,
nyIon, polyacry1ic, and poly-
ester
Cotton, ' wool, silk, and
nylon
2
Wool, silk, ny Ion, and
anod i zed a 1 urn i num
Usage Classification of Dyes
Method ol App 1 i cat i on
Applied usually from neutral
to aci d dyebaths
Fiber impregnated with
coupling component and
treated with solution of
stablIized diazonium salt
Dyed on tannin mordanted cotton,
directly on other materials
Applied from neutral or
slightly alkaline baths
contai ni ng add!tiona 1
electrolyte
F i na aqueous di spers ions often
applied by high temperature
"pressure" or lower temperature
"carrier" dyeings. On cloth
padded dye may be baked on or
"thermof ixed"
Fixation on the fiber under
alkaline conditions
Applied in conjunction with
chelatlng salts of Al, Cr,
and Fe
Major Chemical Types
Azo , i ncluding premeta11i zed
dyes, anthraquinone, triphenyl-
methane, azine, xanthene, nitro,
and nitroso
Azo
Tr iaryImethane, azo, azi ne,
xanthene, th i azi ne, poly-
methi ne, oxazi ne, and
acr i d i ne
Disazo, trisazo, and polyazo as
well as a small number of
phthalocyanine, stiIbene,
oxazi ne, and thi azole
S imple azo, anthraqu i none,
and ni troarylami ne
Azo , anthraqu i none , phthalo-
cyan i ne , and sti Ibene
Anthrqu i none , azo , oxazine ,
tri pheny Imethane , ni troso ,
and xanthene
Remarks
The very important premetal1ized
dyes are members of this class
"Cat i on ic Dyes"
Second most important class of dyes
New fast-growing field of dyes im-
portant for synthet ic f i bers
New class first introduced in 1956;
bonds chemically to the fiber
Sol vent
Organic solvents; examples
are i nks, gasoli ne, 1axquers,
wood sta i n, cosmet ics, plastics,
and wax
Cotton
Dissolution in the appro-
priate solvent or med i urn
Dissolved in water (with
the addition of sodium
sulfide for the insoluble
types); exhausted with
Glauber's salts
Azo, tri pheny Imethane ,
anthraqu i nones , and copper
phthalocyanine derivatives
Sulfur dyes
By vatting (dye solubtlized
by reduction with sodium
hydrosulfite), exhaustion on
the f i ber and reoxi dat ion
Anthraqui none , polycyc 1 ic
qu inones, and i ndi go
Opt ical Br ighteners
All F i bers , soaps, deter-
gents , oils, paints, and
plastics
From aqueous solution or di s-
persion or by incorporation in
the mass
StiIbene, dibenzothio-
phenes, azoles, coumar i n,
and pyrazi ne
~For Food, Drug, and Cosmet ic dyes see Colors for foods, drugs, and cosmet ics.
-Indicates major use*
^Includes all other cellulosic fibers and viscose.
See Brighteners, optical.
-------
application, and representative chemical types. A second
type of classification based on chemical structure has also
been used in the industry. Table 4-9 is arranged according
to chemical classification, giving typical examples of the
characteristic structural units and the application dying
classes which fall in each chemical group. Tables 4-10 and
4-11 show U.S. production and sales of dyes by usage and
chemical classification.
The primary source of organic raw materials for the dye
industry has traditionally been products recovered from the
fractional distillation of coal tar. Hence, the name "coal-
tar dyes" is frequently used in place of the more correct
"synthetic dyes". Coal tar is a by-product of the
gasification (or carbonization) of coal, the primary purpose
of which is the production of coke for steel manufacture and
the gas for industrial and domestic heating. The coal tar
is refined by distillation. From over 300 products which
have been isolated and characterized the most important for
the dye industry are benzene, toluene, xylene, naphthalene,
anthracene, acenaphthene, pyrene, pyridine, carbazole,
phenol, and cresols. The petroleum industry is now
supplying an increasing proportion of the primary raw
materials, notably benzene, toluene, xylene, and more
recently, naphthalene.
In addition to the organic materials above, a great variety
of inorganic chemicals are used in the dye industry. These
include sulfuric acid and oleum for sulfonation, nitric acid
for nitration, chlorine and bromine for halogenation,
caustic soda potash for fusion and neutralization and sodium
nitrate for diazotization, as well as hydrochloric acid
sodium carbonate, sodium sulfate, sodium sulfite, sodium
sulfide, aluminum chloride, sodium dichromate, manganese
dioxide, iron powder, and many others.
The great number of intermediates used to manufacture dyes,
and the comparatively small tonnages involved, make
manufacture by continuous processes uneconomical.
Anthraquinone, produced from anthracene by catalytic air
oxidation, is one of. the very few intermediates used solely
by the dye industry that is made by a continuous process.
Other large-volume intermediates (e.g., aniline, phthalic
anhydride, and phenol) are also manufactured by continuous
process but, as mentioned previously, the bulk of production
is used in other industries.
The batch processes for the production of dyes and
intermediates are carried out in reaction kettles made from
cast iron, stainless steel, or steel, often lined with
222
-------
Table 4-9
Chemical Classification or Dyes
Class
N itroso
Nitro
Azo
monoazo
di sazo
trisazo
polyzao
Azoic
StiIbene
D i phenyI methane
(ketone imi ne)
Tr i ary tmethane
Xanthene
Acrid!ne
ji noli ne
Methine and
Polymeth ine
Thi azole
Indamine and
i ndophenol
Az ine
Su1 fur
Aminoketone and
hydroxyketone
Anthraqu inone
Indigo id
Phthalocyani ne
Oxidation bases
Dyeing Classes
Ac id, disperse, mordant
Ac id, disperse, mordant
Acid, d i rect, mordant,
d i sperse, bas i c , react i ve
Azoic
Di rect, react ive
Basic, acid, mordant
Bas ic ac id , mordant
Basic (suIfur)
Ac id , bas ic, di rect,
di sperse
D i rect, basic, reactive
(sulfur)
Ac id, bas i c, oxi dat i on
(sulfur)
Bas i c, mordant d i rect
(sulfur)
Basic, mordant vat
(sulfur)
Sulfur, vat
Aci d , mordant, vat,
di spersed, bas ic,
di rect, reactive
Vat, acid
Aci d, direct, azoic , vat,
sulfur, basic reactive
Incompletely characterized
oxidation products from
ami nes , d i ami nes, and
ami nophenols
Dyed as a metal chelate
A large and varied class
produced almost without
exception by the coupling
of a diazotized aromatic
amine to a phenol, amine,
pyrazolone, or other cou-
pling component
Insoluble dye formed di-
rectly on fiber from sol-
uble components by di-
azotization and coupling
Class also includes mix-
tures of indeterminate
constitution made for
example by condensation
of nitro stiIbene compounds
and aromatic amines
Brilliantly colored dyes of
only moderate 1 ightfastness
Pure, bri ght hues
Basic dyes used chiefly on
leather; also for ant i -
septIcs
Used for cotton, paper, and
more recently in disperse
dye i ng
Important i n photography
Intermediates for photo-
graphic and sulfur dyes
The first comrnerci ally im-
portant synthetic dye;
Perkin's Mauve belongs
to thi s class
Obtained by heating a vari-
ety of organic compounds
with sulfur or polysulfides
to give disulfide or sulf-
oxide bridges
The natural dye logwood is
included in this class
Condensed polycyclic quin-
onoid dyes of great im-
portance
Derivatives of indigo and
th i oi nd i go
Only blue or green dyes and
pigments (of high light-
fastness) are found in this
cl ass
Ani 1 ine Black
of this class
s a member
223
-------
Table 4-10
U. S. Production of Dyes
by Classes of Application, 1965
Sales
Class of Application
Total
Acid
Azoic dyes and components:
Azoic compositions
Azoic diazo components, bases
(fast color bases)
Azoic diazo components, salts
(fast color salts)
Azoic coupling components
(naphthol AS and derivatives)
Basic
Di rect
Disperse
Fiber-reactive
Fluorescent brightening agents
Food, drug, and cosmetic colors
Mordant
Solvent
Sulfur
Vat
All Other
Production
in 1,000 Ibs.
207.193
20,395
2,100
1,558
2,835
3,172
10,573
36,080
15,514
1,586
19,420
2,923
4,745
9,837
18,648
57,511
296
0_uantity
in 1 ,000 Ibs.
189,965
18,666
2,043
1,310
2,646
2,429
9,553
33,663
13,522
1,558
18,284
2,736
4,246
8,930
17,471
52,439
469
Value
in $l,000's
292,284
39,025
3,968
2,057
2,683
4,669
23,907
50,970
32,878
6,744
34,516
10,238
5,706
15,351
9,960
48,728
884
Unit
Value
$/lb.
1.54
2.09
1.94
1.57
1.01
1.92
2.50
1.51
2.43
4.33
1.89
3.74
1.34
1.72
0.57
0.93
1.88
Source: Synthetic Organic Chemicals, U. S. Tariff Commission
224
-------
Table 4-11
U. S. Production and Sales of Dyes
by Chemical Classification 1964
Sales
Production Quantity Value
Chemical Class jn 1,000 Ibs. in 1,000 Ibs. in $1,OOP's
Total 184,387 178,273 264,023 1.48
Anthraquinone 4l,661 40,675 66,889 1.64
Azo, total 57,897 57,367 96,579 1.68
Azojc 8,787 7,399 12,l4g 1.64
Cyanine 373 362 1,113 3.07
Indigoid 5,729 6,144 3,302 0.54
Ketone Imine 731 782 1,614 2.06
Methine 1,074 974 3,367 3.46
Nitro 720 679 1,258 1.85
Oxazine 172 144 601 4.17
Phthalocyanine 1,987 1,868 4,800 2.57
Quinoline 637 519 1,658 3.19
Stilbene 18,488 17,640 29,166 1.65
Sulfur 17,776 17,268 9,798 0.57
Thiazole 462 480 1,043 2.17
Triarylmethane 5,607 5,312 12,682 2.39
Xanthene 1,312 737 3,473 4.71
All Other 20,974 19,923 14,531 0.73
Source: Synthetic Organic Chemicals, U. S. Tariff Commission
in 1965 total dye production increased 12.5% to
207 million Ib.
225
-------
rubber, glass (enamel), brick,carbon blocks, or stainless
steel. These kettles have capacities ranging from 500 to
10,000 gallons and are equipped with mechanical agitators,
thermometers, condensers, etc., depending upon the nature of
the operation. Products are transferred from one piece of
equipment to another by gravity flow, pumping, or by blowing
with air or inert gas. Plate and frame filter-presses,
boxes, and centrifuges are used for the separation of solid
products from liquids. Where possible, the intermediates
are used for the subsequent manufacture of other
intermediates or dyes without drying. Where drying is
required, air or vacuum ovens (in which the product is
spread on trays) and rotary dryers are used. Less
frequently used are drum dryers (flakers) and spray dryers,
although the latter are becoming increasingly important.
Most of the material handling is manual, and labor costs
represent a significant part of the final dye price.
Automatic process control, based on feedback from
temperature, redox potential, and pH measurement is finding
increasing use in the industry.
The actual manufacture of intermediates and dyes proceeds by
a series of chemical reaction steps. The major steps and
associated chemical reactions typical of each are listed as
follows:
Step 1 - Addition of Functional Groups to JRaw Materials
The attachment of one or more chemical groups to
the aromatic hydrocarbon raw material. Typical
reactions include sulfonation, nitration,
halogenation, and oxidation. Normally, the
starting raw material (such as benzene, toluene
anthracene, etc.) is reacted in the presence of
aqueous sulfuric or nitric acid.
Step 2 - Replacement of Functional Groups on
Intermediates Produced in Step 1
The replacement of the functional groups introduced
in Step 1 by other groups of higher reactivity
which cannot be introduced directly. The starting
materials for this step may be the intermediate
produced in Step 1 or intermediates purchased from
another manufacturer. Typical reactions include:
caustic fusion, to replace a sulfonic acid group
with a hydroxyl group; replacement of a sulfonic
acid group by an amino group by reaction with
226
-------
ammonia; and replacement of halogen atoms by
hydroxyl or amino groups.
Step 3 - further Modification of Functional Groups
On Intermediates from Step 2
This step involves the further modification or
development of functional groups on the inter-
mediates produced in Step 2 (or purchased inter-
mediates) . There can be few generalizations about
these reactions, as each particular case depends on
the specified end product required. Examples of
these reactions include alkylation of functional
groups by reactions of the intermediate with an
alcohol, acylation with organic acid chlorides or
anhydrides, and other rearrangements.
Step 4 - Combination of Two or More Intermediates to
Form a Dye
In this step, two or more intermediates are com-
bined to form a product having a skeletal, if not
complete, dye structure. Typical reactions include
diazotization and coupling, condensation and di-
merization. It should be noted that many of these
products may themselves also be intermediates in
the synthesis of dyes of greater complexity.
When defining the production of dyes and intermediates at a
specific plant, it must be understood that some
manufacturers purchase the intermediates associated with
Steps 1, 2, and 3, so that Step 4 may be the only chemical
reaction processing done at the plant. Other manufacturers
carry out Steps 1, 2, 3, and 4 in the synthesis of a dye
product. Although the final quantities of dye product sold
at each plant might be the same, the actual production
activity (as measured by intermediates production) would be
drastically different.
It should also be noted that production schedules vary
drastically in dye plants.
Both the types and specific quantities of dyes and
intermediates which are manufactured change on a week-to-
week basis.
Because of the nature of the batch operations, it was not
possible to isolate dye products according to chemical or
usage classification for the development of production-based
raw waste load data. Instead, the entire plant was sampled
227
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for periods up to one month. Waste water flows and analyses
were developed on a 24-hour composite basis. Production for
the corresponding period was defined to include all dyes and
intermediates which were separated within the establishment
during the sampling period. A commodity was considered
separated when it was isolated from the reaction mixture
and/or when it was weighed, analyzed, or otherwise measured.
It should be noted that in some cases, it was not possible
to differentiate between production as 100 percent active
ingredients and as standardized material. The difference
between these two relates to quantity of inert diluent which
is added to some dyes prior to shipment to the user. The
raw waste load data presented subsequently are based
primarily on standardized material. The ratio of
standardized material to 100 percent active ingredients can
be as high as 10 to 1. This means that if the raw waste
loads were based on 100 percent active ingredients, the data
reported should be increased by a factor of ten (depending
on the specific plant.)
The following tabulation summarizes the raw waste load data
obtained from six plants sampled during both phases of this
study.
Process RWL for Dyes and Intermediates
Plant Flow BODS _COD TOC
(lit./kxg) (kg/kkg) (kg/kkg) (kg/kkg)
1.(10X occurrence) 5 50 40
(50* occurrence) 795,000 79 1,850 790
(90* occurrence) 156 3,700 1,580
2. (10% occurrence) 17 104 25.0
(50% occurrence) 205,060 62 212 57.0
(90* occurrence) 106 318 89.5
3.(10X occurrence) 278 1,060 350
(50* occurrence) 1.840,000 602 1,595 502
(90* occurrence) 930 2,155 656
4.(sampled 3 days) 32,800 - 195 205
32,800 1.18 19.5 5.24
32,800 - 189 49.2
Process RWL for Dyes and Intermediates
(continued)
228
-------
(lit./kkg)
114,000
114,000
175.000
(kg/kkg)
220
126
59
(kg/kkg) (kg/kkg)
1,075 450
652 269
175 60
Plant Flow BQDfL COD TQC_
5. (sampled 2 days)
6. (sampled 1 day)
Mean based on 50%
Plants 1, 2, 3 395,000 248 1,219 449
Only Plants 1, 2, and 3 were used to compute the mean RWL
shown, as they were sampled for 1 month (30 days.) In such
case, the 50Dt occurrence value was used.
229
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Product: Toner and Lake Pigments
Process RWL Subcategory; D
Pigments are various organic and inorganic water insoluble
substances. They are used in surface coatings, and also in
the ink, plastic, rubber, ceramic, paper, and linoleum
industries to impart color. A large number of pigments are
produced because different products require a particular
choice of material to give maximum coverage, economy,
opacity, color, durability, and desired reflectance.
Organic pigments may be subclassified into toners and lakes.
Toners are insoluble organic dyes that may be used directly
as pigments because of their durability and coloring power.
Toners are used in paints, printing inks, and wallpapers,
and especially for the pigment printing method for textiles,
which employs pigments of metal phthalocyanines and other
types. Lakes result from the precipitation of organic
colors, usually of synthetic origin, with salts of Ca, Ba,
Cr, Al, or phosphomolybdic acid. The dye molecule
frequently contains -OH or -SO3H groups. Such lakes, when
ground in oil or other media, form the pigments of many of
our paints and inks. Some basic dyes are used for the
tinting of paper in a water-dispersed form or
phosphomolybdic (or tungstic) acid lakes. Wallpapers are
frequently colored with lakes from basic dyes containing a
sulfonic acid group. The use of pigments in the "dope"
before spinning rayon, acetate, and synthetic fibers is
growing rapidly and is producing excellent colors of
outstanding all-around fastness.
One facility visited during the field survey produced toners
for the pigment printing of textiles. Figure 4-46 is a
process flow diagram for the manufacture of this product.
Hydrochloric acid, sodium nitrite, water, an amine, and
sulfamic acid are put into the first reactor. The coupler
is prepared in the second reactor. This entails the
addition of a coupling agent, sodium hydroxide, water, and
steam. The reaction products from both reactors then
proceed to a third reactor, where they are combined with
acetic acid, sodium acetate, and water. The pigment which
forms in this reactor is filtered. The solid phase is
recovered as the pigment dye, while the mother liquor is
presently discharged into the sewer.
Samples were obtained on two successive days to characterize
the wastewater from this process. The samples for the two
days indicate that the characteristics of the waste water
are quite variable, attributable mainly to the batch nature
230
-------
FIGURE 4-46
PIGMENT DIAZOTIZATION AND COUPLING
to
OJ
I-1
AMINE
HYDROCHLORIC ACID
SODIUM NITRITE
WATER
SULFAMIC ACID
REACTOR
COUPLER
SODIUM HYDROXIDE
WATER
STEAM
REACTOR
ACETIC ACID
SODIUM ACETATE
WATER
1
REACTOR
PIGMENT
WASTEWATER
-------
of the operation. The second plant produced lakes for use
in paints.
The following tabulation of process RWL, calculated from
flow measurements and the analyses of the waste water
stream, includes data obtained for both plants.
Plant 1 (Toners) Plant 2 (Lakes)
PROCESS FLOW
liter/kkg
gal/M Ib
BOD5RWL
mg/literi
kg/kkg*
COD RWL
mg/liter»
kg/kkg2
TOC RWL
mg/literi
kg/kkg*
1Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
2Raw waste loadings are based on unit weight of pollutant
per 1,000 unit weight of product.
The average RWL from Plant 1 was considered as BPCTCA for toners
while the RWL from Plant 2 was considered as BPCTCA for lakes.
1st Day
313,000
37,500
3,000
940
11,300
3,520
750
235
313,000
37,500
640
200
1,000
315
570
178
2nd Day
1,000,000
1,470
4,930
819
232
-------
Product: Citric Acid
Process: Fermentation of Molasses
Process RWL Subcategory: D
Reactions:
V.2'6 + V -* W7 * C°2 + V
uater
Typical Material Requirements
1000 kg citric acid
Molasses 2500 kg
Nutrients 10 to 15 kg
Sulfuric Acid (95%) 1100 kg
Lime 700 kg
Citric acid is one of the widely employed organic acids.
Its major use is as an acidulant in carbonated beverages,
jams, jellies, and other foodstuffs. Another important use
of citric acid is in the medicinal field, including the
manufacture of citrates and effervescent salts. There are a
few industrial uses, including citric acid as a sequestering
agent, and acetyl tributyl citrate as a vinyl resin
plasticizer.
Except for small amounts produced from citric fruit wastes,
citric acid is manufactured by aerobic fermentation of crude
sugar or molasses. The fermentation changes sugar, a
straight-chain compound, into a branched chain.
Production of citric acid may proceed by either of two
methods: fermentation in shallow pans, or fermentation in
aerated tanks. Both processes may be used simultaneously as
shown in Figure 4-47. In the tray process, a sugar solution
is placed in the trays, and air is circulated for 9 to 12
days over hundreds of shallow, pure-aluminum trays. The
trays are placed in a closed cabinet provided with
facilities for sterilization, ventilation, and temperature
233
-------
FIGURE 4-47
CITRIC ACID-OXAUC ACID-FERMENTATION OF MOLASSES
MOLASSES —fci
WATER — *
DEEP TANK
FERMENTATION
1
WASTEWATER (
FIL
ACI
"
T
!"-t
ROTARY
i
•YCELIUM
3 LANDFILL
CaSO,
LIME-
MOLASSES
HATER
N;
OJ
»ASTE»ATER(2)
WATER
TROMMEL
SCREEN
)
t
PERCOLATION
TANK
l i
_fe
r
TROMMEL
SCREEN
"
CALCIUM
OXALATE
PRECIPITATION
^
-h
BELT
FILTER
CALCIUM
CITRATE
PRECIPITATION
FILTRATION
CALCICUM
CITRATE
DECOMPOSITION
FILTRATION
WASTEWATER (3) SLUDGE
CRYSTALLIZER
fr OXALIC ACID
MYCELIUM
TO LANDFILL
SLUDGE
WASTEHATER (4)
(BAROMETRIC CONDENSER)
WASTEWATER
(BAROMETRIC
CONDENSER)
SLUDGE
FINISHED
CRYSTALLIZER
WASTEWATERl 5)
(BAROMETRI C CONDENSER)
^ ClTRIC ACID
SOLIDS TO LANDFILL
-------
control. After fermentation, the mycelium from the yeast
used is removed from the broth by screens or filters, and
the spent mycelium is washed and disposed. Mycelium wash-
water containing citric acid is combined with acid separated
in the filtration step. The citric acid then passes through
an oxalic acid recovery stage. (Oxalic acid is available
for recovery only from the tray process.) The addition of
calcium sulfate precipitates calcium oxalate. Addition of
sulfuric acid recrystallizes the calcium sulfate, and the
solids are removed by filtration. Hydrous oxalic acid is
then crystallized under a vacuum pulled by a barometric
condenser.
After removal of the oxalic acid, the broth is combined with
the liquor produced in the deep tanks. The essential steps
of the deep tank process are similar to the tray process,
but a different type of mycelium culture is grown and oxalic
acid is not generated as a by-product. Molasses and water
are first introduced into the deep fermentation tanks. Air
is introduced to maintain aerobic conditions and to keep the
tank contents well mixed. The fermentation process is
complete after approximately 4 to 9 days at 30 to 32°C. The
tanks are then emptied and partially filled with boiling
water to sterilize them prior to the next batch. The crude
liquor is filtered to remove the mycelium, and the broth is
combined with the broth produced in the tray processes.
Citric acid is recovered from the broth by precipitation
with calcium hydroxide. The solution is then passed through
a series of filters for removal of the crystallized calcium
citrate. Both filtrate and washwater used during the
filtration process are discharged as waste. The calcium
citrate is then chemically reacted with sulfuric acid to
form calcium sulfate and citric acid. The calcium sulfate
is removed by filtration to purify the citric acid. Some of
the filter cake is recycled to the oxalic acid precipitation
process, while the remainder is wasted. The crude citric
acid is then concentrated from 30 to 60 percent in a double-
effect evaporator equipped with a two-stage steam jet to
pull the vacuum. Barometric condensers are employed
following the steam jets. Since the citric acid does not
vaporize, the only loss in the evaporator is by entrainment.
Thus, entrainment separators are used prior to the con-
densers .
The crude product crystals are redissolved in water during
the finishing step. Treatment processes, including granular
activated carbon, are employed to remove trace heavy metals
and color. The white liquid is then crystallized (utilizing
a barometric condenser), dried, and packaged for sale.
235
-------
To determine the raw waste load, samples of the various
wastestreams were obtained. These wastestreams included
tray and deep tank washwaters, filtrate from the calcium
citrate filtration step, and barometric waste waters from
the purification steps. A waste water stream (barometric
condenser waste water) resulting from the purification of
oxalic acid was included in the raw waste load; thus,
production is expressed as the combined total of oxalic and
citric acids in their anhydrous forms. Process raw waste
loads calculated from flow measurements and the analyses of
these streams are indicated in the following tabulation:
Oxalic plus Citric Acids (Anhydrous form)
Process Flow
liter/Jdcg 477,000
gal/M Ib 57,200
BODS RWL
mg/liter1 690
kg/kkg* 328
COD RWL
mg/liter* 1,380
kg/kkg* 657
TOG .RWL
mg/literi 507
kg/kkg2 242
tjRaw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters. 2Raw
waste loadings are based on unit weight of pollutant per
1000 unit weights of product.
The foregoing data was used as the basis for BPCTCA. The
wastes from this plant are currently discharged to surface
water without treatment.
The analytical results also indicate that, in addition to
the parameters shown in the tabulation, pollution parameters
such as sulfate, nitrogen, chloride, calcium, magnesium, and
zinc may be at levels potentially hazardous to biological
treatment processes. Proper pretreatment to reduce the
aforementioned parameters may be necessary before the
236
-------
wastestreams can be discharged into any biological treatment
unit.
Noncontact waste waters include cooling water and steam
condensate. The total cooling water usage is approximately
107,000 gallons per 1000 Ibs of product. A large quantity
of the cooling water is employed in tube-and-shell heat
exchangers. The total steam usage (live plus reboiler) is
estimated to be 15,500 Ibs per 1000 Ibs of product.
237
-------
Product: Naphthenic Acid
Process; Extraction and Acidification of Caustic Sludge
from Petroleum Refinery
Process RW.L Subcateqory; D
Chemical Structure; Naphthenic acids are cyclo-paraffinic
organic acids and usually are mono-carboxylic
The term "naphthenic acid" is applied to the mixture of
carboxylic acids obtained from the alkali washes of
petroleum fractions. They are complex mixtures of normal
and branched aliphatic acids, alkyl derivates of
cyclopentane- and cyclohexane-carboxylic acids, and
cyclopentyl and cyclohexyl derivates of aliphatic acids.
Naphthenic acids are used chiefly in the form of metallic
salts which are soluble in oils and organic solvents.
Copper naphthenate is an excellent fungicide for wood and
canvas treating. The lead, manganese, zinc, and iron salts
are used as dryers (oxidation catalysts) for paints and
varnishes.
The naphthenic acids are present in caustic sludge primarily
as sodium naphthenates. Figure 4-48 is a process flow
diagram of naphthenic acid recovery. The caustic sludge,
which has been used to scrub the light distillate crude oil
fractions, is treated with water and an alcohol soap
solvent. The resulting oil and soap phases are separated;
the oil phase is stripped with the oil going to fuel and the
solvent recovered overhead. The soap phase is treated with
an oil solvent, and another oil phase/soap phase separation
takes place. The oil phase is recycled to the caustic
sludge, while the soap phase is treated with an acid. The
naphthenic acids are then separated from the solvent.
The solvent proceeds to a stripper where it is recovered as
the overhead and sent to solvent storage. The bottoms from
this column are quenched with water and discharged to the
sewer. The extracted naphthenic acids go to a stripper,
where solvent is taken overhead and sent to storage. The
bottoms from the stripper are vacuum distilled. The bottoms
from the vacuum still are sent to fuel, while the naphthenic
acids are recovered.
Process RWL calculated from flow measurements and the
analyses of waste water streams are indicated in the
following tabulation. In addition, the sulfate
concentrations in the waste water are extremely high may be
potentially hazardous to biological treatment processes.
238
-------
FIGURE 4-48
NAPHTHENtC ACID - EXTRACTION AND ACIDIFICATION
OF CAUSTIC SLUGE FROM PETROLEUM REFINERY
K)
l J
'.a
WATER
CAUSTIC
SLUDGE '
SOAP
SOLVENT
J
OIL & AQUEOUS
PHASES
SEPARATOR
OIL SOLVENT
ACID
SOLVENT TO STORAGE
STEAM
OIL TO FUEL
OIL & AQUEOUS
PHASES
SEPARATOR
T
STEAM JET
AND
BAROMETRIC
CONDENSER
L
WASTEWATER
NAPHTHENIC ACID
TO FUEL
QUENCH WATER
WASTEWATER (2)
-------
PROCESS FLOW
liter/kxg 39,800
gal/M Ib 4,760
BOD5 RWL
mg/literi 3,550
kg/kkg* 141
COD RWL
ing/liter* 7,500
kg/kkg* 298
TOC RWL
mg/literi 2,630
kg/kkg* 104
*Raw waste concentrations are based on unit
weight of pollutant per unit volume of
process waste waters.
£Raw waste loadings are based on unit weight
of pollutant per 1,000 unit weights of product.
These data presented above were the basis for BPCTCA.
The process plant visited during the field data collection
program used direct-contact cooling to reduce the
temperature of the bottoms stream from the soap stripper.
The substitution of noncontact cooling would reduce the
water requirements for this process by approximately 75 per-
cent. However, the raw wasteload would not be appreciably
affected.
240
-------
Product; Monosodium Glutamate (MSG)
Process: Batch Fermentation of Beet Sugar Molasses
Process RWL Subcategory; D
Chemical Reaction:
Fermentation (Glutamic Acid Production)
Fermentation (Glutamic Acid Production)
Beet Sugar + Bacteria Culture + 02 + NH3 >
(sucrose)
NH -CH-COOH + H20 + C02 + Bacteria Mass
CH2-CH2-COOH
gltitanic acid
MSG Conversion and Neutralization
NH -CH-COOH + NaOH > NH2-CH-COOH + H20
2 1 ]
CH2-CH2-COOH CH2-CH2-COONa
mono sodium glutamate
Typical Raw Materials
Beet Sugar Molasses, Ammonia (NH3), Bacteria Culture,
Nutrient Salts, Compressed Air, Diatomaceous Earth,
Filter Aid, Hydrochloric Acid (HCl), Sodium Hydroxide
(NaOH), Steam Cooling Water and Bleaching Activated
Carbon
Monosodium Glutamate (MSG) is an amino acid salt which is
used as a flavor enhancer. MSG is produced by the
conversion of Glutamic Acid (GA) with caustic. There are
several routes to obtaining the GA, including hydrolysis of
Steffen's Waste Liquor with caustic or acid, acid hydrolysis
of wheat and corn gluten, and fermentation of a
carbohydrate.
The process visited during the field data collection program
was the fermentation of beet molasses (sucrose) to produce
glutamic acid. This fermentation reaction is a batch
reaction; subsequent separation processes and the conversion
of the glutamic acid to monosodium glutamate are done on a
semi-continuous basis (refer to Figure 4-49).
241
-------
FIGURE 4-49
SODIUM GLUTAMATE— FERMENTATION OF BEET SUGAR MOLASSES
WH-
u
11 R
CULTURE 1
BEET SUGAR
MOLASSES ' FERMENTATION
VESSELS
T
1
FILTER
AID
CENTRIFUG-
CONDENSATE RECYCl
WASTEWATER
2ND. CROP
CRYSTALLIZATION
-
FILTER / \
_,__,AIQ .^.^ / RFCYCIF V— 1
' RECOVERY 1 1 COOLING j I
WASTEWATER \^^_^^ *
1 f COOLING TOWER
Jk I Bl OWDOWN
HEAT-VCOAGULATION
AND FILTRATION — , EVAPORATION ^
r 1 '
E HIM.
CRUDE
GLUTAMIC
RECYCLE WATER ACID
CRYSTALL-
CRYSTALLIZATION IZATION
AND SEPARATION
—^——— —— — u t nu
I .
MSG
CRYSTALLIZATION
AND
SEPARATION
4—
PH ADJUSTMENT
AND FILTRATION *-
I
MSG DRYING, SCREENING,
PACKAGING AND
SHIPP NG
L.
MSG CONVERSION GA CRYSTALS 4—
FILTRATION AND V FILTRARION AND
DECOLORIZING WASHING ^.BY-PRODUCT
SALES
i i
i i
SPENT CARBON
RECOVERY
I WASTEWATER
SALES
-------
Tiie aerobic fermentation of the sugar beet molasses occurs
in a jacketed vessel, which is either steam-heated or water-
cooled to maintain temperature. The cooling water may be
recirculated without organic pickup. The pH of the
fermenting liquor is monitored and controlled by ammonia ad-
dition. The added ammonia also supplies the amino group in
the product formulation and supplements the nitrogen content
of the raw molasses for bacteria culture growth. The
surplus air from the fermentation vessels contain odorous
compounds; therefore, these gases are sent to the boilers
for air makeup, and the odorous materials are thermally
destroyed.
At the completion of. the fermentation reaction, the bacteria
cell mass (cell cream) is separated via centrifuges and
discarded (point No. 2). This cell mass represents the most
significant part of the raw waste load. The high pollutant
loading and commensurate high substrate content of this
waste stream make it a prime candidate for by-product
recovery and sale.
The clarified centrate is heat treated to precipitate
miscellaneous proteinaceous material. The precipitated
material and any fugitive cell mass are then removed via
vacuum filtration. The resulting sludge is cyclone
classified to recover most of the filter aid material. The
waste stream (point B, appcor cyclone overflow) is
characterized as heavily contaminated with inert and organic
suspended solids. Intermittent discharge of filter precoat
material impacts considerably on the RWL for all parameters
measured (point No. 3).
The clarified filtrate (glutamic acid solution) is
concentrated via a two-stage evaporation process. The
condensate of the first effect is recycled as water make-up
to the fermentation process. The second-stage vapors are
condensed in barometric contact condensers. The barometric
condenser system is serviced with recirculated cooling-tower
water. The blowdown (point No. 7) from this cooling-tower
system was found to be highly contaminated with materials
exerting a significant biochemical oxygen demand.
The concentrated glutamic acid (GA) solution is treated with
concentrated hydrochloric acid to a pH of 3.2, the
isoelectric point of GA. The GA is crystallized out of
solution, filtered, and washed. The wash water, which
represents the major blowdown of impurities from the system,
is recovered and sold as an animal feed supplement,
"Dynaferm". The primary constituent of Dynaferm is GA, but
it also contains many other salts and proteinaceous
243
-------
impurities which escape the heat coagulation/ filtration
treatment. This stream was not sampled during the data-
gatnering survey, but its recovery and sale probably impact
very favorably in reducing the RWL.
The GA crystals are then solubilized and partially converted
to MSG with caustic. The GA/MSG solution is decolorized
with activated carbon. The spent carbon is recovered and
thermally regenerated; this represents a significant in-
process pollution control measure because the color bodies
and other adsorbed impurities are oxidized in the
regeneration furnace. There are three small water
discharges (points No. 4, 5 and 6) which do not
significantly impact on the RWL.
Potential odors in the exhaust gases from the carbon
regeneration facilities are oxidized via a thermal
afterburner. The three discharges (point D) from the carbon
regeneration are significant in volume but contribute little
of any of the pollutants monitored during the survey.
Further downstream processing includes: pH adjustment,
filtration, MSG crystallization, and separation of water and
GA. These streams are recycled in order to retain valuable
product and by-product materials.
The results of combining the two grab composites of all
major contributing sources to waste water discharges yielded
values which compare to 62 percent and 11 percent BOD5
occurrence probability of the historical data; this
indicates that the samples are representative of the MSG
production facility surveyed.
The RWL can be reduced significantly from those levels of
pollutants measured during the data gathering survey. The
approach with the greatest potential for reducing the RWL is
the recovery and sale of cell cream (point No. 2) for animal
feed. It is not possible to mark the impact of cell cream
recovery precisely, but it is estimated that approximately
20 to 50 percent of the suspended solids RWL could be
removed. A somewhat similar impact on the organic and
oxygen-demanding parameters would also be experienced. The
prospects for recovery of this material depend on the
development of nearby markets and favorable economics.
The recovery of the precoat waste water (point No. 3) is
also an attractive alternative to discharge. This material,
soluble and suspended, could be recirculated to achieve
almost total recovery.
244
-------
The RWL for MSG production during the survey and the
estimated impact on RWL in regard to recovery of cell cream
and precoat wastes are shown in the following tabulation:
Sample Sample RWL after
Period fl Period 12 Reduction
PROCESS FLOW
liter/kkg 67,000 67,000 62,200
gal/m Ib 8,030 8,020 7,460
BOD5 RWL
mg/literi 1,510 1,020 980
jcg/kkg* 101 68.4 61
COD .RWL
mg/literi 4,060 4,410 3,600
kg/kkg* 272 296 224
TOC RWL
mg/literi 1,360 1,350 1,090
kg/kkg« 91.4 90.5 67
1 Raw waste concentrations are based on unit weight of
pollutant per volume of process waste waters.
2 Raw waste loading are based on unit weight of pollutant
per 1,000 units of products.
245
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Product: Tannic Acid
Process: Extraction of Natural Vegetable Matter
Process RWL Subcategory; D
Tannic Acid, a glucoside of gallic acid, can be obtained by
extraction of natural vegetable matter with water. The
water extract is then concentrated and upon drying yields
technical tannin, which is used as a mordant in dyeing and
as a source of gallic acid. Extraction of nutgalls with
alcohol or other blcachings, or extraction with mild
reducing agents (such as sodium bisulfite) and evaporation
of the extract yield medicinal grade tannin. Tannic acid is
commonly used for burns, as an astringent, in gargles, and
to precipitate proteins in wineries and breweries.
Figure 4-50 shows a typical flow diagram for tannic acid
manufacture. The raw materials (natural nutgalls) are fed
into the preparation section and ground into small pieces.
The ground material is then batchwise extracted with an
organic solvent. The slurry raffinate phase is diluted with
water, put through a steam stripper for solvent recovery,
and discharged into the sewer. The extract phase, a mixture
of organic solvent, extracted material, and a small amount
of water, is steam stripped for removal of the solvent. The
solvent is then condensed and recycled to the extraction
step.
The steam-stripped aqueous solution containing tannic acid
is cooled and passed through a filter press for removal of
suspended solids. The filtrate (containing tannic acid) is
concentrated in an evaporator before final drying and
packaging. The evaporation step employs steam jets to pull
a vacuum, and the gases are subsequently condensed in
barometric condensers. Waters from the barometric leg are
recycled to the cooling towers for reuse.
The major pollution source from the process is the slurry
waste stream withdrawn as the bottom of the raffinate
stripper. The intermittent reactor washings, as well as
"battery limits" clean-up, also contribute to the RWL of the
process. The amounts of contaminants were estimated to be 5
percent of that of the major waste stream. The results of
the sampling survey are summarized in the following
tabulation.
246
-------
FIGURE 4-50
TANNIC ACID- EXTRACTION OF NATURAL VEGETABLE MATTER
1 NON-CONTACT
1 COOLING WATER
MAKE-UP »
SOLVENT
-j
wiiTFn nun TT F ii u
FEED ^
RAW MATERIAL PREPARATION fc
SOLVENT
RECOVERY
i i
NON-C
COOL
EXTRACTION
AND
STEAM
STRIPPING
1 1
SOLIDS, TRASH WASTEHATER
TO LANDFILL
i
ONTACT
NG WATER .
r
FILTRATION
FILTER CAKE
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-------
Tannic Acid
Sample Sample Sample
Period »1 Period *2 Period »3
.PROCESS FLOW
liter/kkg 10,000 10,000 10,000
gal/M Ib 1,200 1,200 1,200
BODS JRWL
mg/literi 16,100 14,700 15,100
kg/kkg2 161 147 151
COD RWL
mg/literi 109,000 99,400 112,000
kg/kkg2 1,093 995 1,120
TOC RWL
mg/literi 14,000 16,800 21,000
kg/kkg2 140 168 210
*Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste water.
2Raw waste loadings are based on unit weight of
pollutant per 1,000 unit weight of product.
The water from the barometric condensers in the evaporation
step was not included in the foregoing RWL calculations.
Since the organics in the evaporation step are not volatile,
the pollutant loading in the barometric water is low.
Furthermore, this water has been totally recycled for reuse
in tne process.
The analytical results indicate that the high RWL of this
process is attributable to the high amounts of suspended
organic vegetable matter present in the slurry stream. The
removal of suspended solids from this stream can
substantially reduce the RWL of the process. As was
indicated during the sampling survey, the following three
possible methods for removal/disposal of suspended solids
are being investigated.
1. Filtration and landfill disposal of Suspended Solids
(SS).
2. Filtration and incineration of SS.
3. Filtration and recycle of SS into other industrial
and/or agricultural uses.
248
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The RWL of the process should be based on the amounts of
contaminants in the filtrate, and is subject to further
investigation. Noncontact cooling water is employed in the
solvent recovery area and prior to filtration. The total
quantity of noncontact cooling water is estimated to be
approximately 6tH Ibs per Ib of product.
249
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Product: Vanillin
Process; Alkaline oxidation of spent sulfite liquor
Process RWL Subcategorv: D
Chemical Reactions:
Spent sulfite liquor + 02 + NaOH—> C£Ho (OCH ) (CHO) OH
(1ignosulfonic acid) vanillin
Vanillin is one of the most widely used food flavors. Jt is
also used in perfumery and in the deodorizing of
manufactured goods. During the plant visit, company
representatives indicated that approximatley one- third of
the vanillin produced at this plant is used for flavor manu-
facture, with the remaining two-thirds used for perfumes and
other miscellaneous items.
A typical process flow diagram for the manufacture of
vanillin is shown in Figure 4-51.
Waste sulfite liquor containing about 15 percent sulfite
solids (mainly lignosulfonic acid), supplied by paper mills,
is treated with lime in a series of three tanks. In the
first stage (pH = 10.5) calcium sulfate (principally)
precipitates. In the second, the pH is increased to 12.0 to
precipitate calcium lignosulfonate. In the third a further
excess of lime is added. Thickened liquors from the third
stage are then reused as a supplementary lime source in the
first tank. The precipitated calcium lignosulfonate from
the second tank is filtered under vacuum, and redissolved in
a caustic soda solution to yield a solution containing 3.5
percent lignin solids and 10 percent caustic soda.
The alkaline solution is then pumped to a falling-film
contactor countercurrent to a carefully controlled flow of
air, which oxidizes the sulfonate to sodium vanillate. In
one application of the process, the oxidation reaction is
carried out at 1,500 psi and 225°C. Residence time of the
liquid in the contactor is on the order of 4 minutes. The
overall liquor-oxygen ratio equals 0.02 volumes of liquor
per volume of air (STP). At these conditions, an 18 to 20
percent conversion of lignin to vanillin is effected, and
minimum overoxidation is minimized. Because the reaction is
exothermic, the temperature of the effluent liquor rises to
about 250°C. The vanillate from the oxidizer is then
250
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extracted with organic solvents, such as butane or
isopropanol, in a conventional one- or two-stage
countercurrent process. Both the extracted and raffinate
phases are steam stripped to recover, respectively, organic
solvents and vanillate, which are then recycled back to the
process line. The vanillate separated from the organic
solution is further purified by vacuum extractive
distillation followed by acidification. Vanillin is then
recovered by vacuum crystallization, centrifuging, and
vacuum tray-drying.
The air oxidation process described has replaced a former
process in which nitrobenzene was used as the oxidizing
agent. Also, a Canadian plant has installed an air
oxidation process similar to that described, but with lime
replacing caustic as the alkaline agent. Other differences
are the use of carboyhydrate-free waste sulfite liquor from
an alcohol plant, the use of toluene as the extracting
agent, and vacuum distillation to separate vanillin from
contaminating by-products.
The major pollution sources of the process are waters
discharged from the pretreatment of sulfite solution, the
raffinate stripper, the centrifuge filtration, and the steam
jets connected with the barometric condensers. Process
RWL's calculated from the flow measurements and analyses of
the aforementioned waste streams are presented in the
following tabulation.
Sample Period t1 Sample Period #2
PROCESS FLOW
liter/kkg 133,000 133,000
gal/M Ib 15,900 15,900
BODS RWL
mg/literi 17,900 17,500
kg/kkg2 2,380 2,320
COD RWL
mg/literi 118,000 116,000
kg/kkg2 15,600 15,400
TOC RWL
mg/literi 30,400 29,900
kg/kkg2 4,030 3,960
1Raw waste concentrations are based on unit weight of
pollutant per unit volume of process waste waters.
252
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2Raw waste loadings are based on unit weight of
pollutant per 1,000 unit weights of product.
The high raw waste loads shown in the tabulation may be
explained by the fact that spent sulfite liquor is a waste
product from paper mill operations producing only 15 to 20
percent yield to vanillin. The remaining unusable spent
sulfite liquor must be discharged as a waste. The
analytical results also indicate that, in addition to the
parameters shown in the tabulation, pollution parameters
such as dissolved solids, sulfate, and phenol concentrations
may be at levels potentially hazardous to biological
treatment processes.
An average for the two sampling periods was used was the
basis for BPCTCA.
The primary noncontact waste water flows are cooling tower
and boiler blowdown. Samples of the boiler blowdown have
been taken, and the flow has been estimated. Samples of the
cooling tower blowdown were not taken, because typical
analyses were not available and the flows are highly
variable. The cooling tower make-up averages approximately
120 gpm and the cooling water makes approximately 3 cycles.
A phosphate corrosion inhabitor and a biocide are added to
the make-up.
253
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SECTION V
WASTE CHARACTERIZATION
The process RWL data obtained for each of the 55 Secondary
Organic Products were discussed previously in Section IV -
Industry categorization. These descriptions related the raw
waste flows and loadings to specific sources such as
chemical conversions and unit operations within each
product-product grouping. The discussions in this section
relate to the RWL values assigned to each product/process,
and compare waste loadings and concentrations between
product/processes.
The RWL data for each product/process shown in Tables 5-1,
2, 3, and 4 have been inserted in the major process
Subcategories A, B, C, and D. For orientation,
concentrations have been calculated for each parameter by
dividing the raw waste loading by the corresponding contact
process waste water flow. Examination of these data
indicates quite a large spread in flows, loadings, and
resulting concentrations. These values include the
following parameters:
Process Waste Water Flow (liters/kkg of product)
BOD Raw Waste Load (kg BOD/kkg of product)
COD Raw Waste Load (kg COD/kkg of product)
TOG Raw Waste Load (kg TOC/kkg of product)
Although the sampling data indicate that in some cases there
is considerable variation between two manufacturers who
nominally operate the same process, and between different
time sampling periods for the same manufacturers, it was
necessary to specify one set of values for each product-
process grouping. This was done in the most equitable
manner possible from the data available. Rather than
arbitrarily choosing the lowest observed value for each
product-product grouping, an effort was made to choose
values which represent the most complete and reliable data
base. Other factors such as the application of good
housekeeping and in-process controls were also considered in
selecting the raw waste loads values for each
product/process. In cases where alternate means of disposal
are used, such as in the use of deep wells, the total raw
wastes were accounted for as input to the model BPCTCA
biological treatment system. Thus, limitations for
processes where deep wells or other alternate disposal
255
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methods are used would apply in the situation where these
alternate disposal methods were no longer feasible.
The BOD concentrations shown are based on waste waters
coining directly from the process and do not necessarily
represent the waste concentrations which a typical single
stage biological waste treatment plant would accept. If the
plant manufactured a single product which generated
concentrated wastes, these may be diluted with steam
condensate or other noncontact waters prior to biological
treatment depending upon the design and management of the
plant in question. In a multi-product plant, the
concentrated waste water could be diluted with less
concentrated wastes from other processes. In almost all
instances, the actual treatment plant which accomplishes
waste reduction will be accepting the combined wastes from
multiple processes, whose overall concentrations are lower,
because of the addition of waste waters from
product/processes of smaller loads and slightly contaminated
waste waters such as steam condensate, pump seals, etc.
Those 27 product/processes which were selected for effluent
limitations guidelines are included in Table 5-1 thru 5-4.
As indicated in an earlier section of this report, the Phase
II effluent limitations for organic chemicals involve
process-by-process determinations. This approach differs
from that taken in Phase I where process raw waste loads
from processes with similar raw waste loads were combined
and averaged. Effluent limitations were then derived by
application of a reduction factor or concentration to the
average or mean raw waste load for the group of processes.
256
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TABLE 5-1
Major Subcategory A Process Raw Waste Loads
Process Raw Waste Loads
Product
BTX Aromatics
Cumene
p-Xylene
Process Description
Fractional Distillation
Alkylation of Benzene with Propylene
Isomerization, Crystallization, and Filtration
of mixed Xylene
Flow
1/kkg
46.7
44.3
BODS
kg/kkg (mg/1)
0.015 (322)
0.01(238)
COD
TOC
kg/kkg (mg/1) kg/kkg (mg/1)
0.053 (1137) 0.015 (328)
0,025(580) 0.007(159)
to
on
Product
Adiponitrile
Benzole Acid and
Benzaldehyde
Chlorinated Methanes
Chlorobenzene
Chlorotoluene
Diphenylamine
Hexamethylene Diamine
Hexamethylene Diamine
Maleic Anhydride
Methyl Chloride
Methyl Ethyl Ketone
Perchloroethylene
Phthalic Anhydride
Phthalic Anhydride
Tricresyl Phosphate
TABLE 5-2
Major Subcategory B Process Raw Waste Loads
Process Description
Chlorination of Butadiene
Catalytic Oxidation of Toluene with Air
Chlorination of Methyl Chloride & Methane Mixture
Chlorination of Benzene
Chlorination of Toluene
Deamination of Aniline
Hydrogenation of Adiponitrile
Ammonolysis of 1,6 - Hexanediol
Oxidation of Benzene
Esterification of Methanol with Hydrochloric Acid
Dehydrogenation of Sec. - Butyl Alcohol
Chlorination of Chlorinated Hydrocarbons
Oxidation of Naphthalene
Oxidation of o-Xylene
Condensation of Cresol and Phosphorus Oxychloride
Process Raw waste Loads
Flow
1/kkg
9770
2840
2800
50
121,000
526
1,010
1,100
2,300
583
1,310
5,400
593
28,000
BODS
kg/kkg (mg/1)
19.2 (1970)
25.6 (9010)
0.22(77)
0.015 (300)
0.24 ( 2 )
0.087(164)
3.97 (3930)
4 (3640)
108 (47,000)
0.92(1569)
3.92 (3000)
0.44 ( 80 )
Incinerated
0.13 (215)
1.12 ( 40 )
COD
kg/kkg (mg/1)
135 (13,800)
50.8 (17,900)
0.94(335)
0.38 (7700)
1.82 ( 15 )
0.31 (600)
21.1 (20,900)
11.7 (10,600)
287(126,000)
67.8(116,300)
2.1 (1630)
2.83 (525)
0.64 (1080)
11.4 (410)
TOC
kg/kkg (mg/1)
44 (4500)
19.6 (6900)
0.37(132)
0.24 (4780)
0.24 ( 2 )
0.23 (430)
5.15 (5100)
2.5 (2260)
120 (52,500)
17.6 (30,270)
0.68 (520)
0.17 ( 30 )
0.02 ( 34 )
1.96 (70)
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TABLE 5-3
Major Subcategory C Process Raw Waste Loads
Process Raw Waste Loads
Product
Acetic Esters
Ethyl Acetate
Propyl Acetate
Acrylonitrile
p-Aminophenol
Calcium Stearate
Caprolactam
Cyclohexanone Oxime
Cresol, Synthetic
Formic Acid
Hexamethylene letramine
Hydrazine Solutions
Isobutylene
Isopropanol
Oxalic Acid
Pentaerythritol
Propylene Glycol
Propylene Oxide
Saccharin
Sec. Butyl Alcohol
Process Description
Esterification of Ethyl Alcohol with Acetic Acid
Esterification of Propyl Alcohol with Acetic Acid
Ammoxidation of Propylene
Catalytic Reduction of Nitrobenzene
Neutralization of Stearic Acid
DSM Caprolactam Process
Hydroxylamine Process
Methylation of Phenol
Hydrolysis of Formamide
Synthesis with Ammonia
The Raschig Process and Formaldehyde
Extraction from a Mixture of C4 Hydrocarbons
Hydrolysis of Propylene
Nitric Acid Oxidation of Carbohydrates
Aldehyde Condensation
Hydrolysis of Propylene Oxide
Chlorohydrin Process
Synthesis from Phthalic Anhydride Derivatives
Sulfonation and Hydrolysis of Mixed Butylenes
Flow
1/kkg
1,299
1,190
4,470
12,600
54,100
29,100
1910
334
135,000
3,200
30,300
20,400
2,540
436,000
10,200
5,500
63,500
269,000
626
BODS
kg/kkg (mg/1)
0.049 (38)
0.008 (7)
38.7(8620)
41.6 (3300)
13.8 (255)
47.1 ( 1620)
—
47.7 (143,000)
1.05(7.8)
9.2(2875)
9.09 (300)
13.6 (670)
0.99 (393)
1.31 (3)
390 (38,100)
0.016 (3)
31.5 (495)
253 (940)
14.2 (22,800)
COD
kg/kkg (mg/1)
0.102 (79)
0.012 (10)
133(32,800)
73.7 (5850)
32.8 (605)
93 (3200)
6.29 (3300)
101 (303,000)
4.5 (33)
29.4 (9200)
115 (3800)
64.1 (3150)
2.99 (1130)
4.36 (10)
1580 (155,000)
0.055 (10)
143 (2250)
879 (3270)
38.8 (62,000)
TOC
kg/kkg (mg/1)
0.034 (26)
0.005 (4)
57.5(14,400)
21.7 (1730)
23.1 (430)
—
—
34.7 (104,000)
1.4 (10)
9.8 (3060)
0.18 (6)
12.9 (630)
1.32(520)
1.31 (3)
830 (81,200)
0.006 (1)
22.7(355)
384 (1430)
23.9 (38,300)
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TABLE 5-4
Major SubcategoryD Process Raw Waste Loads
Process Raw Waste Loads
KJ
Ul
VD
Product
Citric Acid
Citronellol and Geraniol
Dyes and Dye Intermediate
Fatty Acids
Fatty Acid Derivatives
lonone and Methylionone
Methyl Salicylate
Miscellaneous Batch
Chemicals
Monosodium Glutamate
Naphthenic Acid
o-Nitroaniline
p-Nitroaniline
Pentachlorophenol
Pigments
Toners
Lakes
Plasticizers
Tannic Acid
Vanillin
Process Description
Fermentation of Molasses
Citronella Oil Distillation
Batch Manufacture
Hydrolysis of Natural Fats
Condensation and Cyclization of Citral
Esterification of Salicylic Acid with Methanol
Fermentation of Beet Sugar Molasses
Extraction and Acidification of Caustic Sludge
from Petroleum Refinery
Ammonolysis of o-Nitrochlorobenzene
Ammonolysis of p-Nitrochlorobenzene
Chlorination of Phenol
Diazotization and coupling of amine, sulfuric, etc
Condensation of Phthalic Anhydride
Extraction of Natural Vegetable Matter
Alkaline Oxylation of Spent Sulfite Liquor
Flow
1/kkg
477,000
10,000
947,000
28,000
6,400
9,370
1,735
78,700
62,200
39,800
269,000
39,100
2,960
313,000
1,000,000
650
10,000
133,000
BODS
kg/kkg (mg/1)
328 (690)
58.1(5810)
248 (260)
16.1 (575)
18 (2810)
24 (2600)
22 (12,680)
24.1 (306)
61 (980)
141 (3550)
16 (61)
2.55 (65)
0.94 (318)
570 (1820)
1470 (1470)
54 (82,600)
153 (15,300)
2350 (17,700)
COD
kg/kkg (mg/1)
657 (1380)
111 (11,000)
1219 (1290)
39.6 (1410)
27.9 (4360)
98 (10,000)
93.9 (54,100)
101 (1280)
224 (3600)
298 (7500)
105 (390)
79.1 (2030)
17.5(5880)
1920 (6100)
4930 (4930)
82.6 (127,000)
1070 (107,000)
15,500(117,000)
TOC
kg/kkg (mg/1)
242 (507)
37.7(3770)
450 (475)
9.8 (350)
8.47(1320)
34 (3600)
37.9 (21,800)
31.4 (400)
67 (1090)
104 (2630)
30.9 (105)
22.2 (570)
2.29 (775)
207 (660)
820 (820)
33.4 (51,400)
173 (17,300)
4000 (30,200)
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SECTION VI
SELECTION OF POLLUTANT PARAMETERS
Twenty-eight, parameters were examined during the field data
collection program. These parameters are listed in Table 6-
1, and all field sampling data are summarized in Supplement
B. Based on the degree of impact on the overall
environment, the pollutants which are applicable to control
and treatment were then determined.
The rationale and justification for the major pollutants are
discussed. This discussion will provide the basis for
selection of parameters upon which the actual effluent
limitations were postulated and prepared. These pollutants
parameters for which no effluent limits were established,
but which may be of concern to water quality in certain
locations, are also discussed.
Pollutants observed from the field data that were present in
sufficient concentrations so as to interfere with, be
incompatible with, or pass inadequately treated through
publicly-owned works are discussed in Section XII.
RATIONALE FOR SELECTION OF IDENTIFIED PARAMETERS
5-Day Biochemical Oxygen Demand (BOD5_)
This parameter is an important measure of the oxygen
consumed by microorganisms in the aerobic decomposition of
the wastes at 20°C over a five-day period. More simply, it
is an indirect measure of % the biodegradability of the
organic pollutants in the waste. BOD5_ can be related to the
depletion of oxygen in the receiving stream or to the
requirements of the waste treatment. Low BOD5. values in the
raw waste are frequently the result of the dilutional
effects of non process waters or less contaminated waste
streams. High values are due to a combination of factors,
such as undiluted condenser waters, frequent spills, and a
relatively large amount of drainage of high strength liquids
from the raw material.
Biochemical oxygen demand (BOD) is a measure of the oxygen
consuming capabilities of organic matter. The BOD does not
in itself cause direct harm to a water system, but it does
exert an indirect effect by depressing the oxygen content of
the water. Sewage and other organic effluents during their
processes of decomposition exert a BOD, which can have a
catastrophic effect on the ecosystem by depleting the oxygen
261
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Table 6-1
List of Pollutants and Indicators of Pollution
Examined for the Organic Chemicals Industry
Chemical Oxygen Demand
Biochemical Oxygen Demand
Total Organic Carbon
Total Suspended Solids
Oil (Freon extractables)
Ammonia Nitrogen
Total Kjeldahl Nitrogen
Phenol
Cyanide - Distillation
Color
Sulfate
pH
Acidity
Alkalinity
Chlorine, residual
Total Dissolved Solids
Chlorides
Hardness - Total
Total Phosphorus
Calcium
Magnesium
Zinc
Copper
Iron
Chromium - Total
Cadmium
Col bait
Lead
Nickel
Vanadium
262
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supply. Conditions are reached frequently where all of the
oxygen is used and the continuing decay process causes the
production of noxious gases such as hydrogen sulfide. Water
with a high BOD indicates the presence of decomposing
organic matter and possible high bacterial counts that
degrade its quality and potential uses.
If the BOD5 of the final effluent of an organic chemicals
plant discharged into a receiving body is too high, it will
reduce the dissolved oxygen level in that stream to below a
level that will sustain most fish life; i.e., below about 4
mg/1. Many states currently restrict the BOD5 of effluents
to below 20 mg/1 if the stream is small in comparison with
the flow of the effluent. A limitation of 200 to 300 mg/1
of BOD5 is often applied for discharge to a municipal sewer,
and surcharge rates often apply if the BOD5 is above the
designated limit.
If a high BOD is present, the quality of the water is
usually visually degraded by the presence of decomposing
materials and algae blooms which result from the
decomposition and oxidation of the organic matter.
A 20-day biochemical oxygen demand (BOD20J , sometimes called
"ultimate" BOD is usually a better measure of the waste load
than BOD5, However, the test for BOD20 requires 20 days to
run, and is an impractical measure for most purposes.
Dissolved oxygen (DO) is a water quality constituent that,
in appropriate concentrations, is essential not only to keep
organisms living but also to sustain species reproduction,
vigor, and the development of populations. Organisms
undergo stress at reduced DO concentrations that make them
less competitive and able to sustain their species within
the aquatic environment. For example, reduced DO
concentrations have been shown to interfere with fish
population through delayed hatching of eggs, reduced size
and vigor of embryos, production of deformities in young,
interference with food digestion, acceleration of blood
clotting, decreased tolerance to certain toxicants, reduced
food efficiency and growth rate, and reduced maximum
sustained swimming speed. Fish food organisms are likewise
affected adversely in conditions with suppressed DO. Since
all aerobic aquatic organisms need a certain amount of
oxygen, the consequences of total lack of dissolved oxygen
due to a high BOD can kill inhabitants of the affected area.
The accepted method for BOD analyses is described in the
Standard Methods for the Examination of Water and Waste
Waters published by the American Public Health Association.
263
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The BOD test is a biochemical test for which microorganisms
are used to oxidize the organic matter in the wastewater.
Standard Methods notes that for certain industrial wastes,
more meaningful results may sometimes be realized by the use
of specialized seed material containing organisms adapted to
the use of the organic compounds present. The use of
acclimated seed does not always result in more meaningful
results or higher numerical values. Data using specific
organic chemicals indicated that the use of acclimated seed
can result in lower BOD values than were obtained by using
non-acclimated seed.
The BOD analyses obtained as part of the sampling conducted
during this study were run using reasonable and prudent
steps to evaluate and overcome any potential problems due to
acclimation of seed. The technique that was used in this
study was compared with that used by the laboratory of one
of the large organic chemical industries. The comparison
was good.
BOD5 is included in the recommended effluent limitations
because its discharge to a stream is harmful to aquatic life
since it depletes the oxygen supply. It is also the
parameter most widely used by the industry to characterize
its untreated and treated wastes and is an important
parameter in the design of biological waste treatment
systems.
Chemical Oxygen Demand (COD)
COD is another measure of oxygen demand. It measures the
oxygen required to oxidize organic (and some inorganic)
pollutants under a carefully controlled direct chemical
oxidation by a dichromate sulfuric acid reagent using
specific catalysts.
COD is a much more rapid measure of oxygen demand than BOD5,
and is potentially very useful. However, it does not have
the same significance, and at the present time cannot be
substituted for BOD5, because COD:BOD5 ratios vary with the
types of wastes. The COD measures more than only those
materials that will readily biodegrade in a stream and,
hence, deplete the stream's dissolved oxygen supply.
A major disadvantage is that the COD test does not
differentiate between biodegradable and nonbiodegradable
organic material. In addition, the presence of inorganic
reducing chemcials (sulfides, etc.) and chlorides may
interfere with the COD test.
264
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Standard Methods, the principal reference for analytical
work in this field, cautions that aromatic compounds and
straight-chain alphatic compounds, both prevalent in the
organic chemicals industry, are not completely oxidized
during tne COD test. The addition of silver sulfate, a
catalyst, aids in the oxidation of the straight-chain
alcohols and acids but does not affect aromatic
hydrocarbons. The exact extent of this partial oxidation
has not been documented in the literature.
COD provides a rapid determination of the waste strength.
Its measurement will indicate a serious plant or treatment
malfunction long before the BODjj can be run. A given plant
or waste treatment system usually has a relatively narrow
range of COD:BOD5 ratios, if the waste characteristics are
fairly constant, so experience permits a judgment to be made
concerning plant operation from COD values.
The organic chemicals industry does produce chemicals which
may be in the effluent from a secondary treatment plant and
which can be a source of chemicals in the environment that
can be hazardous to humans, animals, and aquatic life.
These chemicals can be effectively reduced by incorporating
the COD limit in the industry effluent limitation.
The COD test measures the presence of both rapidly
biodegradable and less biodegradable oxygen-demanding
matter. For a specific waste, the difference between the
measured BOD and COD value is an index of the oxygen demand
of organic matter which is resistant to short term
biodegradation. While the laboratory conditions employed in
the COD test will not be found in a receiving stream, a
portion of the oxygen demand measured by the COD will be
exerted in the receiving stream. It is the latter oxygen
demand that is of concern in water pollution control
activities and which requires control, especially in an
industry where many residues may not degrade rapidly.
The COD test is a reasonable index for the presence of
organic chemicals in a waste or effluent, is a reasonable
estimate of the ultimate oxygen demand of the wastes from
this industry, and can be a measure of hazardous materials
in the environment.
Effluent limitations guidelines were established for the COD
pollutant parameter for BATEA. Its use for BPCTCA and New
Sources is not precluded if a suitable correlation with BODS
is established.
Total Organic Carbon (TOC)
265
-------
TOC is a measure of the amount of carbon in the organic
material in a waste water sample. The TOC analyzer
thermally oxidizes a small volume of sample at 150°C. The
carbon dioxide from the combustion chamber is condensed and
sent to an infrared analyzer, where the carbon dioxide is
monitored. This carbon dioxide value corresponds to the
total inorganic value. Another portion of the same sample
is thermally oxidized at 950°C, which converts all the
carbonaceous material to carbon dioxide; this value
corresponds to the total carbon value. TOC is determined by
subtracting the inorganic carbon from the total carbon
value. Only organic matter capable of being incorporated
into the small sample volume (approximately 40 millimeters)
can be measured. Primarily soluble and colloidal organic
material can be measured by this analysis.
The TOC value is affected by any one or more of the
following:
1. The water vapor may be only partially condensed and
may appear in the infrared adsorption band of
carbon dioxide and can therefore inflate the
reported value.
2. The sample volume involved in the TOC analyzer is
so small (approximately 40 microliters) that it can
easily become contaminated, with dust, for example.
3. Industrial wastes from the organic chemicals
industry with low vaporization points may vaporize
before 150°C and therefore be reported as inorganic
carbon.
Effluent limitations were not established for the TOC
parameter, although its use is not precluded if a suitable
correlation with BOD5 or COD is established. It has only
been in recent years that TOC has been used as a measure of
waste water quality.
Total Suspended Solids (TSS)
This parameter measures the suspended material that can be
removed from the waste waters by laboratory filtration.
Suspended solids are a visual and easily determined measure
of pollution and also a measure of the material that may
settle in tranquil or slow-moving streams. A high level of
suspended solids is an indication of high BOD£. Generally,
suspended solids range from one-third to three-fourths of
the BOD_5 values in the raw waste. Suspended solids are also
266
-------
a measure of the effectiveness of solids removal systems
such as clarifiers and fine screens.
Suspended solids frequently become a limiting factor in
waste treatment when the BOD5 is less than about 20 mg/1.
In fact, in highly treated waste, suspended solids usually
have a higher value than the BOD5, and in this case, it may
be easier to lower the BODJ5 even further, perhaps to 5 to 10
mg/1, by filtering out the suspended solids. Suspended
solids in the treated waste waters generally correlate well
with BOD5, COD, and total volatile solids.
Suspended solids also may inhibit light penetration and
thereby reduce the primary productivity of algae
(photosynthesis). Because of the strong impact suspended
solids can have on receiving waters, suspended solids were
included in the effluent limitations recommended in this
report.
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, and various organic matter from the
manufacturing process. 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 fisia-food bottom fauna or the
spawning ground of fish. Deposits containing organic
materials may deplete bottom oxygen supplies and produce
hydrogen sulfide, methane, and other undesirable 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 ox 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.
267
-------
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 in the stream or lake
bed, they are often damaging to the life in water, and they
retain the capacity to displease the senses. Solids, when
transformed to sludge deposits, may do a variety of damaging
things, including blanketing the stream or lake bed and
thereby destroying the living spaces for those benthic
organisms that would otherwise occupy the habitat. When of
an organic and therefore decomposable nature, solids use a
portion or all of the dissolved oxygen available in the
area. 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.
TSS RWL values for the Phase 2 products surveyed are
presented in Tables 6-2 through 6-5. TSS raw waste loads
are generally not a significant factor in this industry.
Much of the TSS eventually discharged to surface waters are
biological solids which have been produced in the end-of-
pipe biological treatment facilities many of which are
removed before effluent discharge. The effluent limitations
are partially based on a concentration value which will be
attainable with adequate solids handling facilities. This
subject is discussed in detail in Section VIJ.
Total Volatile Solids (TVS)
The total volatile solids measurement is a rough measure of
the amount of organic matter in the waste water. Actually,
it is the amount of combustible material in both the total
dissolved solids and total suspended solids. Total volatile
solids in the raw and treated waste waters from this
industry generally correlate fairly well with SS, grease,
and COD. Because of these correlations and because total
volatile solids is a relatively easy parameter to determine,
it could be used as a rapid method to determine a serious
plant or treatment system malfunction. Volatile solids in
receiving waters are food for microorganisms.
Effluent limitations for total volatile solids were not
established because TVS will be limited by limitations on
other pollutant parameters such as BOD5_ and suspended
solids.
Oil
268
-------
Table 6-2
Miscellaneous RWL for Subcategory A
Flow, gal/1 ,000 Ibs
Phenol
mg/1
kg/kkg
NH -N
•Wl
kg/kkg
TKN
mg/1
kg/kkg
CN
mg/1
kg/kkg
Sulfate
mg/1
kg/kkg
Oil
mg/1
kg/kkg
T-P
mg/1
kg/kkg
Zn
mg/1
kg/kkg
Cu
mg/1
kg/kkg
Fe
mg/1
kg/kkg
Cr-Total
mg/1
kg/kkg
Cd
mg/1
kg/kkg
TSS
mg/1
kg/kkg
IDS
mg/1
kg/kkg
cr
mg/l
kg/kkg
Phase
p-Xylene
5.25
.16
.00001
1.0
.00005
3.12
.00013
2.6
.00011
7^6
.0327
it. 76
.00021
.287
.00001
.44
.00002
2.30
.00010
2.50
.00011
< .05
0
17.3
.00076
162
.0711
32
.0014
I I Data
Cumene
.04
14.6
Negl igible
3.4
Negligible
8.2
Negl igible
.02
Negligible
12.3
Negl igible
21
Negligible
.005
Negl igible
.13
Neg 1 i g i b 1 e
.05
Negligible
109
.00003
.01
Negl igible
.01
Negligible
100
.00003
138
.00004
37
.00001
Supplementary Phase 1 RWL Data
BTX
87.5
.155
.00009
1.27
.0010
4.05
.0028
140
.0872
251
.709
.45
.00035
1 .49
.00095
< .08
< .00006
1.45
.00090
5.16
.00315
< .05
< .00005
44.5
.0270
2,045
.343
168
.103
BTX
52.3
1.98
.00087
18.0
.00785
49.3
.0215
5,860
2.56
26
.011
1.112
. 00049
.116
. 00005
.09
.00004
13.8
.006
.171
. 00008
.127
.00006
331
.1445
47,600
20.8
3,280
1.43
BTX
5.56
.2
.00001
142.7
.00662
322.4
.0154
.818
. 00004
1,400
.0649
9
.0004
.033
.00000
.343
.00002
.05
.00000
1.57
.00007
.01
.00000
.01
.00000
9
.0004
21
.00097
36
.00169
Ethyl Benzene
55.5
1.94
. 00069
13.2
. 00546
18.2
.00772
23.9
.0160
55
.0318
.079
. 00004
2.46
.00087
.18
.00006
2.55
. 00096
1.26
.00089
.052
.00003
61.5
.0254
20,300
6.68
4,410
1.48
Ethyl Benzene
39.7
1.03
.000335
11.8
.00387
105.5
.0355
12.8
.00578
9
.00298
.0178
.00006
30.5
.0102
21.5
.00721
7.9
.00149
.807
.00027
.051
.00002
5
.00172
13,200
4.44
50,800
16.9
269
-------
Table 6-3
Miscellaneous 1?WL for Subcategory B
Product
Benzole Acid via Benzene
Maleic Anhydride via Benzene
Maleic Anhydride via Benzene
Adiponi t ri le
Chloromethanes
Chloromethanes
Chlorotolulene
Methyl Ethyl Ketone
Methyl Ethyl Ketone
Di pheny 1 ami ne
HMDA (Adiponitrile)
HMDA (Adiponitrile)
Hexamethylene Diamene (Hexanediol)
Methyl Chloride
Methyl Chloride
Methyl Chloride
Perch loroethylene
Phthalic Anhydride (o-xylene)
Tricresyl Phosphate
Flow
qal/1000 Ib
340
788
274
1170
V3C.
33o
71.6
14, 500
156
63
203
121
132
1,430
101
69.9
642
71.2
3,350
mq/1
.16
2.10
1.47
.103
.03
.035
nit
. UH
.01
.638
.073
.01
.01
.07
.05
.09
.21
10.8
Phenol
kq/kkq
. 00044
.014
.0034
.00102
nnnm
. UUUU/
.00002
nnli.3 (\
, UUH-jD
.00001
.00108
.00073
.00001
.00011
.00006
.00003
.00048
.00013
.304
NH--
mq/l J
<15.3
16.6
1,940
-i
1.95
< 1.4
2.1
15,500
4,540
3,080
7,630
.1
1.9
.55
.2
10.4
3.65
N
kq/kkq
0.043
.109
18.9
nm Q 1
. uu I y r
.00116
< .0018
.00167
8.15
7.69
3.1
8.40
.0012
.0016
.000325
.00107
.00618
.102
mg/1
33.5
16.6
3,730
21
. I
6.05
5.2
4.5
16,700
4,000
4,400
9,170
1.9
69.3
1.9
4.6
18.8
11.8
TKN
kq/kkq
.095
.109
36.4
nncQ i
. UU5j I
.0036
.0068
.00355
8.78
6.78
4.44
10.10
.0230
.0585
.00110
.0247
.0112
.344
CN
mq/1 kq/kkq
0 0
187 1.83
.638 .00108
16.7 .0202
Supplementary Phase 1 RWL Data
Acetone
Ethylene Dichloride
Vinyl Chloride
Vinyl Chloride
Styrene
Styrene
276
28.2
17.0
135
733
250
.27
<.01
.36
1.83
1.13
.00006
0
. 00040
.0112
.00252
0
10.4
.7
23.5
5.15
0
.0024
.00079
.143
. 00763
1.8
17.9
4.6
2.85
29.8
12.3
.0041
.0042
. 00066
.00379
.182
.0364
-------
Table 6-3
(continued)
Miscellaneous RWL for Subcategory B
Product
Benzole Acid via Benzene
Maleic Anhydride via Benzene
Maleic Anhydride via Benzene
Ad i pon i t ri 1 e
Chloromethanes
Chloromethanes
Chlorotolulene
Methyl Ethyl Ketone
Methyl Ethyl Ketone
Diphenylamine
HMDA (Adiponitrile)
HMDA (Adiponitrile)
Hexamethylene Diamene (Hexanediol)
Methyl Chloride
Methyl Chloride
Methyl Chloride
Perch 1 o roethy 1 ene
Phthalic Anhydride (o-xylene)
Tricresyl Phosphate
mg/1
.78
101
30
1.58
14.3
.68
.29
.30
1.11
.25
5.81
18.8
4.12
5.98
.5
1.31
Fe
kg/kkg
.00222
.665
.069
.0154
.0403
.00054
.000155
.00219
.000113
.00028
.0695
.0159
.0024
.0321
.0003
.0366
Cr-Total
mg/1
.076
1.74
.0973
7.7
.05
.05
.141
.053
.02?
.050
.644
.088
9.45
4.01
.041
kq/kkq
.00022
.0040
.000953
.0217
.00004
.00003
.00024
.000053
.00003
.00060
.00054
.00005
.0507
.00238
.00115
Ca
mg/1
.10
.42
< .05
.161
.050
.05
.05
.05
.05
.027
.052
.050
.215
.05
.01
.041
Supplementary Phase 1
Acetone
Ethylene Dichloride
Vinyl Chloride
Vinyl Chloride
Styrene
Styrene
37.7
2.06
13.6
.33
7.9
.0089
.00029
.0153
.00199
.00149
.05
.06
2.55
.056
.015
.00001
.00001
.00287
.00034
.00002
.10
<.05
.05
< -05
.055
kq/kkq
.00029
.0028
<. 00011
.00156
.00014
.00004
.00003
.000085
.00005
.00003
.00062
. 00004
.000125
.00027
.00001
.00115
RWL Data
.00002
.00001
.00006
.00031
.000025
TSS
mg/1
118
17
2,380
56.3
89
1,170
8.5
53.5
4
28
7,100
1,380
25.5
29
4
14.5
26
68
8.5
1,230
kg/kkg
.334
.109
5.44
.55
.251
.702
. 00447
.0905
.00404
.333
6.001
.802
.136
.0172
.110
.00341
.00369
.0766
.0504
.118
TDS Cl"
mg/1
34,900
56,000
53,700
124,000
28,300
4,100
467
16
3,600
535
29
336
23,500
117,000
1,700
541
615
46,000
85,200
13,300
69.8
42.5
kq/kkq mg/1
98.9 290
371
122 18
1,210 83,400
79.3
2.45 3,570
56.5 325
56
.00842 6,300
6.10 26
. 541 489
.0316 5,190
4.01 11,500
19.8 2,760
Aft 1
9.20 33,600
.321 92
17.2 2,560
10.8 18,900
12.1 18,900
15.0 11,300
.263 7.7
.114 3.5
kq/kkg
.823
.0421
814
2.12
39.3
.0446
17.6
.0437
.492
5.71
137
2.330
180
.0547
71.5
4.45
4.45
12.7
.0472
.0072
-------
Table 6-3
(continued)
Miscellaneous RWL for SubcategOry B
Sulfate
Product
Benzole Acid via Benzene
Maleic Anhydride via Benzene
Maleic Anhydride via Benzene
Ad i pon i t ri 1 e
Chloromethanes
Chloromethanes
Chlorotolulene
Methyl Ethyl Ketone
Methyl Ethyl Ketone
D i pheny lami ne
HMDA (Adiponitrile)
HMDA (Adiponitrile)
Hexamethy 1 ene Diamene (Hexanediol)
Methyl Chloride
Methyl Chloride
Methyl Chloride
Pe rch 1 o roet hy 1 ene
Phthalic Anhydride (o-xylene)
Tricresyl Phosphate
Acetone
Ethylene Dichloride
Vinyl Chloride
Vinyl Chloride
Styrene
Styrene
mg/1
36.3
156
349
2,590
28.0
1.20
1.0
1.0
5.12
15.7
.538
3,020
482
5,800
6,840
106
54
3.60
21.0
4.0
145
< 4.29
1.0
kq/kkq
.103
1.53
.98
10.5
3.39
.0016
. 00079
.00053
.00869
.0158
.00059
36
8.85
446
36.6
.0630
1.513
.0083
.0049
.00057
.163
.0265
.00208
Oil
mq/1 kg
43
482 3.
2,020 4.
1,270 12.
12
0
441
280
18
1,380 2.
1,270 12.
36
460 5.
33
121
0
6
10.5
Supplementary Pha
2,370 5.
13
19
7
<29
18
|/kkq
121
17
62
400
0335
00017
576
222
0096
33
3
0398
500
0278
0707
000445
00351
297
wl RWL
47
0029
00264
00744
181
0013
T -
mq/1
.27
137
12.3
.678
.12
.005
.02
1.057
.375
2.03
.212
.057
.172
.039
.0535
1.24
1.19
Data
.388
.048
1.36
.059
.027
.015
P
kq/kkq
.00078
.902
.12
.00190
.000075
.00001
.00002
. 00056
.000635
.00205
. 00023
.00068
.00015
.00002
.000285
.00074
.0335
.00090
.00001
.00019
.00055
.00016
.00001
Zn
mq/1
4.19
5.42
.26
.328
5.16
8.06
.49
.085
74.5
.28
.022
14
23.6
33.8
4.05
.72
.327
.11
.33
2.0
.053
.135
kq/kkq
.012
.036
.00059
.0032
.0145
. 00482
.00039
. 000045
.000125
.000283
.00002
.168
.200
.0198
.022
. 00043
.0914
.00002
.00005
.00226
.00032
.00019
Cu
mq/1
.06
2.20
.17
48
.19
.15
.08
.05
.185
.05
.08
.07
26.3
.125
.06
.07
.07
.85
.70
.205
<.05
.115
kg/kkq
.00017
.014
.00039
.479
.00054
.0182
.00006
.00003
.00032
.00005
. 00003
. 00084
.0223
.000075
.00032
.00004
.00197
.00020
.00010
. 00023
.00031
.00011
-------
Table 6-4
Miscellaneous RWL for* Subcategory c
Product
Hexamethy 1 ene Tetramine
Hexamethy 1 ene Tetramine
Synthetic Cresols
Sec. Butyl Alcohol
1 sobuty 1 ene
Pentaerythritol
Ethyl Acetate
Propyl Acetate
Calci um Stearate
Hydrazi ne
N) . ,
~J Isopropanol
Acryloni tri le
Acryloni tri le
Propylene Glycol
Propyl ene Oxide
Saccharin
Formic Acid
Oxal ic Acid
Flow
ga 1/1 000 Ib
557
384
250
7,780
2,440
1 ,230
155
142
6,460
3,630
304
338
570
6,580
32,200
16,000
52,300
Phenol
mg/1
.16
< .01
6,500
• 38
.01
.17
0
0
.014
.01
2.28
.165
1.15
.01
.0056
—
kg/kkg
.00072
< .00002
13.6
.025
.00012
.00178
0
0
.00067
.00003
.0064
.000705
.0381
.0032
.00087
—
NH^-N
mg/1
395
7,040
2.7
0
9.4
< 1.1
.8
.7
.8
1.0
1.1
13,600
2,600
1.5
130.3
1.43
3.2
kg/kkg
2.39
22.5
.0057
0
.190
< .012
.00104
.00083
.0568
.0297
.00281
38.3
10.26
.0875
35.0
.193
1.41
TKN
CN
mg/1 kg/kkg mg/1 kg/kkg
6,650 32.90
8,260 26.50
4.9
3.1
12.6
2.3
<2.0 < .
1.8
6.0
11.3
1.95 .
22,000 62.
4,040 16.
3.8
5,980 604
5.07 .
5.9 2.
0102 < .02 < .00004
200
256
023
00259
00213
322 .0202 .00110
342
00501
1 270 .755
9 197 .970
209
686 .02 .00267
56 .02 .00873
Sulfate
mg/1
367
<9.3
<6.5
1 ,280
1 ,210
2,570
1 .0
1.4
112
—
366
2,700
5,300
—
2,060
4.67
5.6
kg/kkg
2.22
•C.0050
< .0136
83.2
24.50
26.20
.00129
.00166
6.06
—
.931
64.10
74.3
—
553
.623
2.44
Oil
mg/1
50
131
5,600
408
1 ,030
369
203
265
169.2
19
15
168
135
98.5
43.4
kg/kkg
.19
.419
11.6
26.4
20.9
3.77
.263
.314
9.10
.569
.0380
.475
.657
5.45
5.77
T-P
mg/1
1.07
.177
.169
.079
1.07
.081
0
.05
.0134
.176
.153
.152
6.15
1.04
.07
.042
.02
kg/kkg
.0044
.00057
.00035
.0051
.0217
.00082
0
.00006
.00072
.00533
.00039
.00043
.0298
.061
.0189
.00561
.00873
-------
Table 6-^
(cont i nued)
Miscellaneous RWL for Subcategory C
Product
Hexamethy lene Tetramine
Hexamethy 1 ene Tetramine
Synthetic Cresols
Sec. Butyl Alcohol
1 sobuty lene
Pentaerythri tol
Ethyl Acetate
Propyl Acetate
Calcium Stearate
ij Hydra zine
1 sopropanol
Aery loni t r i le
Acrylonitri le
Propylene Glycol
Propylene Oxide
Sacchari n
Formic Acid
Oxalic Acid
In
mg/1
I.It
.19
.543
.43
.07
.049
.13
2.84
.052
2.10
26.6
.071
.107
.01
kq/kkg
.0085
.0004
.0055
.00056
.00008
.00262
.00394
.00722
.00002
.00922
1.56
.0190
.0142
.00436
Cu
mg/1
.07
<.05
.20
.77
3.49
.04
.14
.17
<.05
.05
.25
27.6
.08
.05
kq/kkq
.00032
<.0001
.0020
.001
.00414
.00221
.00424
.000435
< .00014
.000235
.0138
7.43
.0107
.0218
Fe
mg/l
1.61
6.07
8.65
.55
1.15
.108
4.30
2.88
3.13
4.24
23.9
.25
.05
.01
kg/kkg
.0097
.013
.088
.00071
.00136
.00590
.130
.00731
.0088
.0182
1.39
.0665
.0104
.00436
Cr-Total
mq/1
2.02
<.05
1.44
<.05
<.05
.041
.15
.051
<.05
.01
.334
.051
.089
.1
kg/kkq
.012
< .0001
.0148
< .00007
<. 00006
.00221
.00454
.00013
<. 00014
.00005
.0191
.0138
.0119
.0436
mg/1
<.05
<-05
.093
<.05
< .05
.041
.23
.051
<.05
.052
.111
.062
.05
.05
Cd
kg/kkg
<. 00023
< .0001
.00095
<. 00007
<. 00006
.00221
.00697
.00013
<. 00014
.00024
.00614
.0166
.00668
.0218
mq/1
27
6
9
129
1
10
26,
1,180
4.
630
184
4,520
33
6.
10
TSS
kq/kkg
.106
.0192
.0188
1.31
.00129
.0119
.7 1.43
35.8
,5 .0121
1.78
.915
263
8.83
,8 .902
4.36
TDS
mq/1
2,320
971
33.5
289,000
66
85
6,020
118,000
2,550
57,200
36,500
44 , 700
14,500
40.9
36
kq/kk
10
3
2,960
324
3,590
6
161
181
2,460
3,900
5
15
Cl
g_ mq/1
.1 40.5
.11 234
.0699 1.5
868
.085 7
.101 3
3,870
98,700
.46 214
858
125
24,800
5,050
.45 6
.7 6
-
kq/kkg
.149
.75
.0034
8.86
.00917
.00335
208
991
.542
2.42
.616
351
356
.792
2.58
-------
Table 6-5
Miscellaneous RWL for Subcategory D
Product
Fatty Acids
Fatty Acids
Fatty Acids S- Derivat.
Fatty Acids S- Derivat.
Fatty Acids
Pentachloro Phenol
Esters from Fatty Acids
Methyl Esters
Fatty Acid Derivatives
Fatty Acid Derivatives
to
Di Naphthenic Acid
Glycerine
Fatty Acid Amides
Batch Chemicals
Tannic Acid
Sodium Glutamate
Plasticizers
(Diethyl Phthalate)
Dyes
para-Nitro-Ani 1 i ne
Miscellaneous Dyes
Azo Dye
or t ho-N i tro-An i 1 i ne
Vanil lin
Citric Ac i d
lonone S- Methyl lonone
Citronellol Geraniol
Pigments
Flow
ga 1/1 000 Ib
7,900
440
1 ,450
7,650
1 ,230
354
1 ,070
15,200
550
688
4,760
5,450
2,250
9,560
1 ,200
8,030
78.3
3,930
4,680
221,000
26,200
32,200
15,900
57,100
1,370
1 ,220
37,500
Phenol
mg/l
.02
.55
1.19
.06
.45
37.6
.07
.33
.20
.54
8.57
10.6
.04
1.83
2.37
.05
.01
.63
7.15
16.9
7.49
7.97
147
.07
1.04
0.00
1.81
kg/kkg
.00138
.00202
.0144
.00383
.00461
. .112
.00059
.042
.00088
.00312
.341
.482
.00068
.19
.0238
.0035
.00001
.0205
.279
31.2
1.57
2.14
19.5
.0309
.0119
0.00
.565
NH^-N
mg/l
1.5
121
934
86.1
3.75
211.
4.2
40
.55
620
3.7
5.5
7,730
36.7
1.8
241
1.1
82.1
1,590
17.2
15.0
1 ,150
4.05
51.8
44.5
9.3
2.1
kg/kkg
.096
.447
11.30
5.50
.0364
.624
.0375
5.07
.0026
3.56
.147
.248
145
2.87
.0180
16.1
.00073
2.69
62.1
31.7
3.08
310
.536
24.7
.508
.0943
.66
TKN CN Sulfate
mg/l
4.6
147
2,430
87.6
21.2
223
13.4
109
15.5
640
6.3
980
7,890
53.7
350
458
3.9
126
1,830
27.9
32.3
7,340
181
91.2
53.2
11.8
13.9
kg/kkg mg/l
.303
.540
29.4
5.59
.218
.661 .078
.119
13.8
.071
3.67
.252 .02
44.5
148
4.16 .02
3.50 .0237
30.6
.00258 .04
4.14 .041
71.5
51.6 .432
6.63 .085
976
24.0
43.5 .026
.608 .023
.120 .020
4.33 .026
kg/kkg mg/l
33.6
1 ,400
1 ,860
280
456
.00023 914
192
960
640
1,640
.00079 3,230
4,200
2.4
.00154 1,220
.000303
279
.00003 2,030
.0014 548
92.5
.756 1,020
.018 442
103
5,330
.0123 2,070
.00026 3,980
.00020 40.8
.00814 564
kg/kkg
2.21
152
22.5
17.9
4.69
2.70
1.71
122
2.94
9.42
128
191
.045
98.6
18.7
1.33
18.0
3.61
578
90.7
27,700
33.5
986
45.3
0.414
176
Oi
mg/l
54
1,190
600
68
1,070
3
4,000
4,250
701
470
255
8
467
43.7
85
12,500
334
332
74
106
10
72
19
383
2,630
67
1
kg/kkg
3.56
4.36
7.25
4.34
11.0
.00753
35.7
540
3.22
2.70
10.12
.350
8.77
3.35
5.69
8,170
10.9
12.9
136
24.8
2,600
9.56
8.85
4.37
26.6
20.9
T-P
mg/l
.39
129
2.30
.10
9.53
.038
3.3
1.67
2.01
18.7
.194
2.48
.02
1.90
595
15.2
3.29
.142
.493
10.5
.53
.531
.087
.101
.293
.797
.309
kg/kkg
.026
.474
.0279
.00638
.0982
.000115
.029
.212
.0092
.107
.0077
.113
.00038
.156
5.96
1.02
.00215
.0047
.0193
19.4
0.113
.143
.0115
• 0484
.00335
.00808
.0967
-------
Product
Fatty Acids
Fatty Acids
Fatty Acids 6- Derivat.
Fatty Acids & Derivat.
Fatty Acids
Pentachloro Phenol
Esters from Fatty Acids
Methyl Esters
Fatty Acid Derivatives
Fatty Acid Derivatives
Naphthenic Acid
Glycerine
Fatty Acid Amides
Batch Chemicals
Tannic Acid
Sodium Glutamate
Plastic! zers
(Diethyl Phthalate)
Dyes
para-Nitro-Anal ine
Miscel laneous Dyes
Azo Dye
ortho-Nitro-Anal ine
Van! llin
Citric Acid
lonone & Methyl lonone
Citronellol Geraniol
Pigments
mq/l
.104
.755
.17
.31
.272
.66
.79
1.60
.302
.450
1.312
3.52
3.95
.413
.229
.580
.287
.068
.517
3.30
1.47
.317
.135
In
kg/kkg
.0069
.00913
.011
.0032
.00081
.0059
.00365
.0092
.0139
.021
.110
.0347
.00258
.0135
.00892
1.07
.0614
.0184
.0686
1.57
.0168
.00322
.0423
Cu
mg/l
.05
.075
.05
1.73
.185
.05
.22
.10
.05
.40
.587
.807
97.9
61.6
.11
.775
.941
.05
7.59
.25
9.31
.08
.26
kq/kkq
.0033
.00091
.0032
.0178
.00054
.00045
.00101
.00057
.002
.0182
.0442
.008
.0640
2.02
.00417
1.43
.192
.0142
1.00
.120
.106
.00081
.207
Table 6-5
(continued)
Miscellaneous RWL for Subcategory
Fe Cr-Total
mq/l
3.06
3.67
.01
2.85
2.69
21.4
2.71
2.13
9.23
11.2
9.05
28.6
4.49
5.62
5.48
7.62
4.58
2.79
17.2
2.09
25.0
.98
.85 .
kg/kkg
.202
.0445
.00064
.0294
.00796
.191
.0125
.012
.366
.509
.744
.287
.00293
.184
.214
14.1
.940
.751
2.28
.996
.286
.00996
.266
mg/l
.05
.65
.05
2.32
.107
.35
3.25
.05
.05
.05
1.15
.518
.076
.56
.147
12.6
.572
.05
.458
.055
.112
.062
.05
274
kg/kkg
.0033
.0079
.0032
.0240
.000315
.0031
.0149
.0029
.002
.0022
.0988
.00519
.00005
.0184
.00574
3.28
.136
.0135
.0607
.0264
.00128
.00063
.0157
Cd
mq/l
.05
.05
.05
.05
.15
.05
.05
.05
.05
.05
.05
.035
.151
.06
.073
.050
.049
.05
.186
.05
.090
.061
.05
kg/kkg
.0033
.00061
.0032
.00052
.00044
.00045
.00023
.00029
.002
.0022
.00383
.00035
.0001
.00197
.00287
.0924
.0100
.0135
.0247
.0238
.00102
.00062
.0157
TSS
mg/l
128
780
669
57
1 ,560
155
3,840
551
211
748
68.5
928
494
42.6
2,260 151
101
121
1 ,430
99.3
270
24.5
78
124
21
59
kq/kkq
8.44
2.86
8.10
3.64
16.0
.46
34.2
69.8
.970
4.29
2.72
42.2
9.27
3.28
,000
.0661
3.97
56.1
20.4
72.5
3.26
36.9
1.42
.211
18.4
TDS
mg/l
370
61,900
2,630
1,150
1,378
8,950
770
5,720
3,490
2,400
7,690
10,800
3,250
108,000
1 ,650
94,800
42,400
13,300
3,150
2,020
348,000
41,300
85 ,400
32,600
.,^0
kg/kkg
24.4
227
31.8
73.4
14.2
26.4
6.8?
726
16.0
13.9
305
4go
261
1,080
110
61.9
1,390
520
646
543
46,300
19,700
976
330
606
Cl"
mq/l
67
84
61.5
4,320
70
291,000
i 119
27
100
71
69
17
326
776
85
160
12,100
5,780
1,130
306
—
15,500
191
282
621
kq/kkq
4.40
.308
.074
275
.721
860
1.06
3.41
.651
.408
2.75
.791
6.12
61.4
5.68
.104
398
226
215
82.3
—
423
2.18
2.86i
194
-------
Oil, also called oil and grease, or hexane solubles, is a
pollutant, parameter that can be in the wastes from the
organic chemicals industry. Oil can form unsightly films on
the water, interfere with aquatic life, disturb biological
processes in sewage treatment plants, and become a fire
hazard. It also can be a food source for microorganisms and
exhibit an oxygen demand. Oil emulsions may adhere to the
gills of fish or coat and destroy algae or other plankton.
Deposition of oil in the bottom sediments can serve to
prohibit normal benthic growths, thus interrupting the
aquatic food chain. Soluble and emulsified material
ingested by fish may taint the flavor of the fish flesh.
Water soluble components may exert toxic action on fish.
Floating oil may reduce the re-aeration of the water surface
and in conjunction with emulsified oil may interfere with
photosynthesis. Water insoluble components damage the
plumage and coats of fowls and water animals. Oil and
grease in a water can result in the formation of
objectionable surface slicks preventing the full aesthetic
enjoyment of the water. Oil spills can damage the surface
of boats and can destroy the aesthetic characteristics of
beaches and shorelines.
Oil RWL's for the major Subcategories A, B, C, and D are
presented in Tables 6-2 through 6-5. Although some of the
raw waste loads show high concentrations of oil, effluent
limitations were not considered to be warranted. The
explanation for not limiting oil discharges is that this
pollutant parameter is of secondary importance whenever
other primary pollutant parameters are controlled such as
for BOD5 and TSS.
Nitrogen
Ammonia nitrogen in the raw waste is one of the many forms
of nitrogen in a waste stream. Anaerobic decomposition of
protein, which contains organic nitrogen, leads to the
formation of ammonia. Thus, anaerobic lagoons or digesters
can produce increased levels of ammonia. Also, septic
(anaerobic) conditions within the plant in traps, basins,
etc., may lead to increased ammonia in the waste water.
Ammonia is a common product of the decomposition of organic
matter. Dead and decaying animals and plants along with
human and animal body wastes account for much of the ammonia
entering the aquatic ecosystem. Ammonia exists in its non-
ionized form only at higher pH levels and is the most toxic*
in this state. The lower the pH, the more ionized ammonia
is formed and its toxicity decreases. Ammonia, in the
presence of dissolved oxygen, is converted to nitrate (NO3)
*The term toxic or toxicity is used herein in the normal
scientific sense of the word and not as a specialized term
referring to Section 307(a) of the Act.
277
-------
by nitrifying bacteria. Nitrite (NO2), which is an
intermediate product between ammonia and nitrate, sometimes
occurs in quantity when nitrification is not complete.
Nitrification may occur in an aerobic treatment process and
in streams. Ammonia will deplete the oxygen supply in a
stream and its oxidation products are nutrients for aquatic
growth.
Nitrates are considered to be among the poisonous
ingredients of mineralized waters, with potassium nitrate
being more poisonous than sodium nitrate. Excess nitrates
cause irritation of the mucous linings of the
gastrointestinal tract and the bladder. The symptoms are
diarrhea and diuresis. Drinking one liter of water
containing 500 mg/1 of nitrate can cause such symptoms.
Infant methemoglobinemia, a disease characterized by certain
specific blood changes and cyanosis, may be caused by high
nitrate concentrations in the water used for preparing
feeding formulae. While it is impossible to state precise
concentration limits, water containing more than 10 mg/1 of
nitrate nitrogen (NOJ-N) is not recommended for infants.
Nitrates are also harmful in fermentation processes and can
cause disagreeable tastes in beer.
In streams polluted with municipal sewage, up to one half of
the nitrogen in the sewage may be in the form of unionized
ammonia, and municipal sewage may carry up to 35 mg/1 of
total nitrogen. It has been shown that at a level of 1.0
mg/1 unionized ammonia, the ability of hemoglobin to combine
with oxygen is impaired and fish may suffocate. Evidence
indicates that ammonia exerts a considerable toxic effect on
all aquatic life within a range of less than 1.0 mg/1 to 25
mg/1, depending on the pH and dissolved oxygen level
present.
Ammonia can add to the problem of eutrophication by
supplying nitrogen through its breakdown products. Some
lakes in warmer climates, and others that are aging quickly
are sometimes limited by the nitrogen available. Any
increase will speed up the plant growth and decay process.
Kjeldahl Nitrogen (TKN)
Kjeldahl Nitrogen (TKN) measures the amount of ammonia and
organic nitrogen. When used in conjunction with the ammonia
nitrogen, the organic nitrogen can be determined by the
difference. Under septic conditions, organic nitrogen
decomposes to form ammonia. Kjeldahl nitrogen is a good
indicator of the crude protein in the waste water. Kjeldahl
278
-------
nitrogen has not been a common parameter for regulation and
is a much more useful parameter for raw waste than for final
effluent.
Ammonia and TKN RWJL data of major significance for Tables 6-
2 thru 6-5 are summarized below:
Subcategory Product RWL Concentration
NH3 TKN-N
mg/1 mg/1
B Acrylonitrile 13,600 22,000
Diphenylamine 15,500 16,700
Hexamethylenediamine 7,630 9,170
C Hexamethylenetetramine 7,040 8,260
D Fatty Acids and
Derivatives 1-7,730 5-7,890
Effluent limitations were not established for TKN since as a
rule those product processes with high TKN values also have
nigh BOD values. The oxidation of the TKN would be at least
partially measured by the BOD analysis. Thus limitations
based upon BOD would in effect control the TKN in the
effluent. Ammonia limitations were not established for
these product processes. It was determined that need for
such limitation should be established on a plant by plant
basis after consideration of the individual plants' total
waste load and/or water quality considerations in effect at
the particular plant location.
Phenol
Phenols and phenolic wastes are derived from petroleum,
coke, and chemical industries; wood distillation; and
domestic and animal wastes. Many phenolic compounds are
more toxic than pure phenol. Their toxicity varies with the
combination and general nature of total wastes. The effect
of combinations of different phenolic compounds is
cumulative.
Phenols and phenolic compounds are both acutely and
chronically toxic to fish and other aquatic animals. Also,
chlorophenols produce an unpleasant taste in fish flesh that
destroys their recreational and commercial value.
It is necessary to limit phenolic compounds in raw water
used for drinking water supplies, as conventional treatment
methods used by water supply facilities do not normally
remove phenols. The ingestion of concentrated solutions of
279
-------
phenols will result in severe pain, renal irritation, shock
and possibly death.
Phenols also reduce the utility of water for certain
industrial uses, notably food and beverage processing, where
it creates unpleasant tastes and odors in the product.
Phenols can be removed in biological treatment systems and
reduce the problems described above.
Phosphorus
Phosphorus, commonly reported as P, is a nutrient for
aquatic plant life and can therefore cause an increased
eutrophication rate in water courses. The threshold
concentration of phosphorus in receiving bodies that can
lead to eutrophication is about 0.01 mg/1. Phosphorus in
raw waste from the organic chemical industry is a result of
cleaning operation. In some cases phosphorus is part of the
product processes formulation and would enter the waste
water from spills and equipment wash down.
During the past 30 years, a formidable case has developed
for the belief that increasing standing crops of aquatic
plant growths, which often interfere with water uses and are
nuisances to man, frequently are caused by increasing
supplies of phosphorus. Such phenomena are associated with
a condition of accelerated eutrophication or aging of
waters. Phosphorus is not the sole cause of eutrophication,
but there is evidence to substantiate that it is frequently
the key element required by fresh water plants and is
generally present in the least amount relative to need.
Therefore, an increase in phosphorus allows use of other,
already present, nutrients for plant growths. Phosphorus is
usually described, for this reasons, as a "limiting factor."
When a plant population is stimulated in production and
attains a nuisance status, a large number of liabilities are
immediately apparent. Dense populations of pond weeds make
swimming dangerous. Boating and water skiing and sometimes
fishing may be eliminated because of the mass of vegetation
that serves as an physical impediment to such activities.
Plant populations have been associated with stunted fish
populations and with poor fishing. Plant nuisances may emit
vile stenches, impart tastes and odors to water supplies,
reduce the efficiency of industrial and municipal water
treatment, impair aesthetic beauty, reduce or restrict
resort trade, lower waterfront property values, cause skin
rashes to man during water contact, and serve as a desired
substrate and breeding ground for flies.
280
-------
Phosphorus in the elemental form is particularly toxic, and
subject to bioaccumulation in much the same way as mercury.
Colloidal elemental phosphorus will poison marine fish
(causing skin tissue breakdown and discoloration). Also,
phosphorus is capable of being concentrated and will
accumulate in organs and soft tissues. Experiments have
shown that marine fish will concentrate phosphorus from
water containing as little as 1 ug/1.
Adequate amounts of phosphorus must be in a waste water to
permit adequate microbial growth in a biological treatment
system and hence obtain satisfactory treatment plant
performance. If inadequate amounts of phosphorus are not in
a waste water to achieve adequate biological treatment plant
performance, supplemental phosphorus will have to be added
to the waste water of the biological treatment system.
Effluent limitation for phosphorus were not established
because in general the concentrations in the waste water
were too low to warrant specific controls.. With specific
product/processes phosphorus may have to be added, rather
than removed, to assure adequate phosphorus for the
biological rreatment systems.
Total Dissolved Solids, Chlorides, Sulfides
In natural waters the dissolved solids consist mainly of
carbonates, chlorides, sulfates, phosphates, and possibly
nitrates of calcium, magnesium, sodium, and potassium, with
traces of iron, manganese and other substances.
Many communities in the United States and in other countries
.use water supplies containing 2000 to 4000 mg/1 of dissolved
salts, when no better water is available. Such waters are
not palatable, may not quench thirst, and may have a
laxative action on new users. Waters containing more than
4000 mg/1 of total salts are generally considered unfit for
human use, although in hot climates such higher salt
concentrations can be tolerated whereas they could not be in
temperate climates. Waters containing 5000 mg/1 or more are
reported to be bitter and act as bladder and intestinal
irritants. It is generally agreed that the salt
concentration of good, palatable water should not exceed 500
mg/1.
Limiting concentrations of dissolved solids for fresh-water
fish may range from 5,000 to 10,000 mg/1, according to
species and prior acclimatization. Some fish are adapted to
living in more saline waters, and a few species of fresh-
water forms have been found in natural waters with a salt
281
-------
concentration of 15,000 to 20,000 mg/1. Fish can slowly
become acclimatized to higher salinities, but fish in waters
of low salinity cannot survive sudden exposure to high
salinities, such as those resulting from discharges of oil-
well brines. Dissolved solids may influence the toxicity of
heavy metals and organic compounds to fish and other aquatic
life, primarily because of the antagonistic effect of
hardness on metals.
Waters with total dissolved solids over 500 mg/1 have
decreasing utility as irrigation water. At 5,000 mg/1 water
has little or no value for irrigation.
Dissolved solids in industrial waters can cause foaming in
boilers and cause interference with cleanness, color, or
taste of many finished products. High contents of dissolved
solids also tend to accelerate corrosion.
Specific conductance is a measure of the capacity of water
to convey an electric current. This property is related to
the total concentration of ionized substances in water and
water temperature. This property is frequently used as a
substitute method of quickly estimating the dissolved solids
concentration.
Cyanide
Cyanides in water derive their toxicity primarily from
undissolved hydrogen cyanide (HCN) rather than from the
cyanide ion (CN~). HCN 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 threefold increase in the rate of the
lethal action of cyanide.
Cyanide has been shown to be poisonous to humans, and
amounts over 18 ppm can have adverse effects.
Trout and other aquatic organisms are extremely sensitive to
cyanide. Amounts as small as 0.1 part per million can kill
them. Certain metals, such as nickel, may complex with
cyanide to reduce lethality especially at higher pH values,
but zinc and cadmium cyanide complexes are exceedingly
toxic.
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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.
The following is a summary of cyanide data which is
significant:
Subcateqory Product RWL Concentration
mg/1
B Adiponitrile 187
Hexamethylene Diamine 20
C Acrylonitrile 270
The cyanide results from the previous processes were
determined using Standard Method's Cyanide Titration
Procedure with and without preliminary distillation. The
following is a comparison of results from one plant:
CN
mg/1
Standard Method Titration Procedure 4,870
Standard Method Distillation - Titration Procedure 940
It has been reported that aldehydes combine with HCN to form
cyanohydes during distillation and that this complex
interferes with the titration procedure. Based on this
analytical experience, it is recommended that only the
titration procedure be used with these waste waters.
Heavy Metals
Heavy metals (such as zinc, copper and cadmium) are
inhibitory to microorganisms because of their ability to tie
up proteins in their key enzyme systems.
Cadmium
Cadmium in drinking water supplies is extremely hazardous to
humans, and conventional treatment, as practiced in the
United States, does not remove it. Cadmium is cumulative in
the liver, kidney, pancreas, and thyroid of humans and other
animals. A severe bone and kidney syndrome in Japan has
been associated with the ingestion of as little as 600
ug/day of cadmium.
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Cadmium is an extremely dangerous cumulative toxicant,
causing insidious progressive chronic poisoning in mammals,
fish, and probably other animals because the metal is not
excreted. Cadmium could form organic compounds which might
lead to mutagenic or tetratogenic effects. Cadmium is known
to have marked acute and chronic effects on aquatic
organisms.
Cadmium acts synergistically with other metals. Copper and
zinc substantially increase its toxicity. Cadmium is
concentrated by marine organisms, particularly molluscs,
which accumulate cadmium in calcareous tissues and in the
viscera. A concentration factor of 1000 for cadmium in fish
muscle has been reported, as have concentration factors of
3000 in marine plants, and up to 29,600 in certain marine
animals. The eggs and larvae of fish are apparently more
sensitive than adult fish to poisoning by cadmium, and
crustaceans appear to be more sensitive than fish eggs and
larvae.
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 chrornate 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 organisms and other lower
forms of aquatic life are extremely sensitive. 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.
Copper
Copper salts occur in natural surface waters only in trace
amounts, up to about 0.05 mg/1, so that their presence
generally is the result of pollution. This is attributable
to the corrosive action of the water on copper and brass
tubing, to industrial effluents, and frequently to the use
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of copper compounds for the control of undesirable plankton
organisms.
Copper is not considered to be a cumulative systemic poison
for humans, but it can cause symptoms of gastroenteritis,
with nausea and intestinal irritations, at relatively low
dosages. The limiting factor in domestic water supplies is
taste. Threshold concentrations for taste have been
generally reported in the range of 1.0-2.0 mg/1 of copper,
while as much as 5-7.5 mg/1 makes the water completely
unpalatable.
The toxicity of copper to aquatic organisms varies
significantly, not only with the species, but also with the
physical and chemical characteristics of the water,
including temperature, hardness, turbidity, and carbon
dioxide content. In hard water, the toxicity of copper
salts is reduced by the precipitation of copper carbonate or
other insoluble compounds. The sulfates of copper and zinc,
and of copper and cadmium are synergistic in their toxic
effect on fish.
Copper concentrations less than 1 mg/1 have been reported to
be toxic, particularly in soft water, to many kinds of fish,
crustaceans, mollusks, insects, phytoplankton and
zooplankton. Concentrations of copper, for example, are
detrimental to some oysters above .1 ppm. Oysters cultured
in sea water containing 0.13-0.5 ppm of copper deposited the
metal in their bodies and became unfit as a food substance.
Zinc
Occurring abundantly in rocks and ores, zinc is readily
refined into a stable pure metal and is used extensively for
galvanizing, in alloys, for electrical purposes, in printing
plates, for dye-manufacture and for dyeing processes, and
for many other industrial purposes. Zinc salts are used in
paint pigments, cosmetics, Pharmaceuticals, dyes,
insecticides, and other products too numerous to list
herein. Many of these salts (e.g., zinc chloride and zinc
sulfare) are highly soluble in water; hence it is to be
expected that zinc might occur in many industrial wastes.
On the other hand, some zinc salts (zinc carbonate, zinc*
oxide, zinc suifide) are insoluble in water and consequently
it is to be expected that some zinc will precipitate and be
removed readily in most natural waters.
In zinc-mining areas, zinc has been found in waters in
concentrations as high as 50 mg/1 and in effluents from
metal-plating works and small-arms ammunition plants it may
*The term toxic or toxicity is used herein in the normal
scientific sense of the word and not as a specialized term
referring to Section 307(a) of the Act.
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occur in significant concentrations. In most surface and
ground waters, it is present only in trace amounts.
Concentrations of zinc in excess of 5 mg/1 in raw water used
for drinking water supplies cause an undesirable taste which
persists through conventional treatment. Zinc can have an
adverse effect on man and animals at high concentrations.
In soft water, concentrations of zinc ranging from 0.1 to
1.0 mg/1 have been reported to be lethal to fish. Zinc is
thought to exert its toxic action by forming insoluble
compounds with the mucous that covers the gills, by damage
to the gill epithelium, or possibly by acting as an internal
poison. The sensitivity of fish to zinc varies with
species, age and condition, as well as with the physical and
chemical characteristics of the water. Some acclimatization
to the presence of zinc is possible. It has also been
observed that the effects of zinc poisoning may not become
apparent immediately, so that fish removed from zinc-
contaminated water to zinc-free water (after 4-6 hours of
exposure to zinc) may die 48 hours later. The presence of
copper in water may increase the toxicity of zinc to aquatic
organisms, but the presence of calcium or hardness may
decrease the relative toxicity.
Observed values for the distribution of zinc in ocean waters
vary widely. The major concern with zinc compounds in
marine waters is not one of acute toxicity, but rather of
the long-term sub-lethal effects of the metallic compounds
and complexes. From an acute toxicity point of view,
invertebrate marine animals seem to be the most sensitive
organisms tested. The growth of the sea urchin, for
example, has been retarded by as little as 30 ug/1 of zinc.
Zinc sulfate has also been found to be lethal to many
plants, and it could impair agricultural uses. Due to its
potential toxicity, zinc can be a pollutant parameter
requiring the establishment of an effluent limitation.
The following concentrations of heavy metals have been
reported as being inhibitory to biological treatment:
Pollutant Inhibitory Concentration
mg/L
Copper 1.0
Zinc 5.0 - 10.0
Cadmium 0.02*
Total Chromium 3.0
Iron 5.0*
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*Inhibitory to anaerobic sludge digestion.
The following is a summary of the metals data from Tables 6-
2 through Tables 6-5 which is considered significant in
regard to inhibition of biological treatment:
Subcategory
B
Product
Adiponitrile
Chloromethanes
Methyl Chloride
HMDA
Maleic Anhydride
Perchloroethylsne
Propylene Oxide
Saccharin
Hydrazine
Plasticizers
Dyes
Vanillin
Miscellaneous
Metal RWL Concentration
mg/L
48 - Copper
14.3 - Iron
7.7 - Total Chromium
26.3 - Copper
0.21 - Cadmium
18.8 - Iron
33.8 - Zinc
74.5 - Zinc
0.4 - Cadmium
9.45 - Total Chromium
0.1 - Cadmium
23.9 - Iron
26.9 - Zinc
27.6 - Copper
0.23 - Cadmium
97.9 - Copper
61.6 - Copper
17.2 - Iron
12.6 - Total Chromium
Effluent limits are established for copper for the
manufacture of plasticizers, dyes, pigments and toners.
Chromium is limited for the manufacture of dyes, pigments
and toners. These metals were considerably higher in load
based on Ibs per 1000 Ibs product for these product
segments. Therefore effluent limits were established for
copper and chromium for these segments.
pH, Acidity and Alkalinity
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Waters with pH outside the 6.0 to 9.0 range can affect the
survival of most organisms, particularly invertebrates. The
usual pH for raw waste falls between 6.0 and 9.0. This pH
range is close enough to neutrality that it does not
significantly affect treatment effectiveness or effluent
quality. However, some control may be required particularly
if pH adjustment has been used in the production processes.
The pH of the waste water then should be returned to its
normal range before discharge. The effect of chemical
additions for pH adjustment should be taken into
consideration, as new pollutants could result.
Acidity and alkalinity are reciprocal terms. Acidity is
produced by substances that yield hydrogen ions upon
hydrolysis and alkalinity is produced by substances that
yield hydroxyl ions. The terms "total acidity" and "total
alkalinity" are often used to express the buffering capacity
of a solution. Acidity in natural waters is caused by
carbon dioxide, mineral acids, weakly dissociated acids, and
the salts of strong acids and weak bases. Alkalinity is
caused by strong bases and the salts of strong alkalies and
weak acids.
The term pH is a logarithmic expression of the concentration
of hydrogen ions. At a pH of 7, the hydrogen and hydroxyl
ion concentrations are essentially equal and the water is
neutral. Lower pH values indicate acidity while higher
values indicate alKalanity. The relationship between pH and
acidity or alkalinity is not linear or direct.
Waters with a pH below 6.0 are corrosive to water works
structures, distribution lines, and household plumbing
fixtures and can thus add such constituents to drinking
water as iron, copper, zinc, cadmium and lead. The hydrogen
ion concentration can affect the "taste" of the water. At a
low pH, water tastes "sour". The bactericidal effect of
chlorine is weakened as the pH increases, and it is
advantageous to keep the pH close to 7. This is very
significant for providing safe drinking water.
Extremes of pH or rapid pH changes can exert stress
conditions or kill aquatic life outright. Dead fish,
associated algal blooms, and foul stenches are aesthetic
liabilities of any waterway. Even moderate changes from
"acceptable" criteria limits of pH are deleterious to some
species. The relative toxicity to aquatic life of many
materials is increased by changes in the water pH.
Metalocyanide complexes can increase a thousand-fold in
toxicity with a drop of 1.5 pH units. The availability of
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many nutrient substances varies with the alkalinity and
acidity. Ammonia is more lethal with a higher pH.
The lacrimal fluid of the human eye has a pH of
approximately 7.0 and a deviation of 0.1 pH unit from the
norm may result in eye irritation for the swimmer.
Appreciable irritation will cause severe pain.
Effluent limits for pH have been established for all
subcategories to decrease the difficulties noted above.
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SECTION VII
CONTROL AND TREATMENT TECHNOLOGIES
The waste loads discharged from the organic chemicals
industry to receiving streams can be reduced to desired
levels, including no discharge of pollutants, by
conscientious water management including recycle, in-plant
waste controls, process 'revisions, and by the use of waste
treatment systems.
Control and treatment technologies which are available for
waste waters in the organic chemicals industry can encompass
the entire spectrum of waste water treatment technology.
The selection of a particular technology is dependent on the
technology economics and the desired magnitude of the final
effluent, concentration. Control and treatment technology
may be divided into two major groupings:
1. In-plant pollution abatement.
2. End-of-pipe treatment.
After discussing the available performance data, conclusions
will be made relative to the reduction of various pollutants
commensurate with the following distinct technology levels.
1. Best Practicable Control Technology Currently
Available (BPCTCA).
2. Best Available Technology Economically Achievable
(BATEA) .
3. Best Available Demonstrated Control Technology
(BADCT) for New Source Performance Standards.
To assess the economic impact of these proposed effluent
limitations on the industry, model treatment systems have
been proposed which are considered capable of attaining the
recommended RWL reduction. It should be noted that the
particular systems chosen for use in the economic analysis
are not the only systems which are capable of attaining the
specified pollutant reductions.
There exist many alternate systems which, either taken
singly or in combination, are capable of attaining the
effluent limitations and standards recommended in this
report. These alternate choices include:
1. Various types of end-of-pipe waste water treatment.
2. Various in-plant modifications and installation of
pollution control equipment.
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3. Various combinations of end-of-pipe and in-plant
technologies.
The complexity of the Organic Chemicals Industry dictated
the use of only one treatment model for each effluent level.
The use of a single treatment model for these waste waters
is done only to facilitate the economic analysis and should
not be inferred as the only feasible technology to meet the
limitations.
The individual manufacturer within the Organic Chemicals
Industry must make the ultimate choice of what specific
combination of pollution control measures is best-suited to
his situation in complying with the limitations and
standards presented in this report.
In-Plant Pollution Abatement
The complexity of the organic chemicals industry precludes
the possibility of providing a specific list of process
modifications or control measures which are applicable to
all of the Industry's processes.
The elimination or reduction of in-plant pollution depends
upon any one of the following factors:
1. Plant process selection to minimize pollution.
Present corporate environmental awareness requires that
new products and processes be evaluated with regard to
their environmental aspects.
2. The modification of process equipment to improve
product recovery or to minimize pollution.
These areas have been discussed thoroughly in the Phase
I Development Document.
3. Maintenance and good housekeeping practices
minimize pollution.
The competitive nature of the industry in conjunction
with the flammable nature of many of its products
requires most producers to operate their plants in the
most: efficient manner possible. This necessitates good
maintenance and housekeeping practices. However, there
are other segments of the industry that have minimized
maintenance expenditures and whose management does not
adequately fund their environmental control staff nor
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support them in their quest to enforce rigid
housekeeping regulations.
4. The age of the plant and process equipment as it
impacts on pollution.
Poorly maintained process equipment does not warrant
consideration under this age consideration. The real
problem is that older plants generally have larger waste
water loads than newer plants. In addition, older plant
layouts often do not allow for economic modifications to
the process equipment to minimize pollution and, in many
cases, make segregation of storm and process waters
difficult but not impossible.
Tne following in-process controls will lessen the raw waste
load to the treatment facility:
1. the substitution of noncontact heat exchangers
for direct contact water cooling;
2. the use of nonaqueous quench media as a substitute
for water where direct contact quench is required;
3. the recycle of process water, such as between
absorber and stripper;
4. the reuse of process water (after treatment) as a
make-up to evaporative cooling towers through which noncontact
cooling water is circulated;
5. the use of process water to produce low pressure
steam by noncontact heat exchangers in reflux condensers
of distillation columns;
6. recycle cooling for contact water systems
(barometric condensers);
7. the recovery of spent acids or caustic solutions
for reuse;
8. the recovery and reuse of spent catalyst solutions;
9. the use of nonaqueous solvents for extraction of
products with subsequent recovery of solvents; and
10. addition of demisters.
Guidelines for Prevention, Control and Reporting of Spills
have been developed by the Manufacturing Chemists
Association (MCA) for use in the organic chemicals industry
and other industries. This 22 page document notes how to
assess tne potential of spills and how to prevent spills.
Plants in the organic chemical industry should use such
guidelines as part o± good practice in-plant waste control.
Numerous articles are available that indicate that
significant in-plant controls can be instituted in organic
chemical plants to decrease the waste output.
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The production of organic chemicals results in many types of
contaminated waste waters, and the treatment methods
employed cover the range of known practical techniques. In-
plant control is the first step in instituting treatment
practices. Such controls include the salvage of unreacted
chemicals, recovery of by-products, multiple reuse of water,
good housexeeping techniques to reduce leaks and spills, and
changes in processing methods. These controls can result in
reducing the concentrations of almost all potential
pollutants and can, most importantly, reduce the volumes of
waste waters requiring treatment.
Flow equalization equipment can be an important part of in-
plant waste water control. Equalization facilities consist
of a holding tank and pumping equipment designed to reduce
the fluctuations of waste water flow through materials
recovery and waste treatment systems. They can be
economically advantageous, whether the industry is treating
its own wastes or discharging into a city sewer after some
pretreatment. The equalizing tank should have sufficient
capacity to provide for uniform flow to treatment facilities
throughout a 24-hour day. The tank is characterized by a
varying flow input and a constant flow output.
The major advantages of equalization are that treatment
systems can be smaller since they can be designed for the
24-hour average rather then the peak flows, and many
secondary waste treatment systems operate much better when
not subjected to shock loads or variations in feed rate.
Many plants do not require any special tanks to achieve flow
equalization because of the manner in which they are
operated. For example, plants with large continuous systems
or a number of batch systems (10 to 20) with staggered
cooling cycles that operate most of the day are inherently
achieving a near-constant flow of waste water. Other plants
need to institute procedures or equipment to achieve flow
and waste load equalization.
Drainage or spills from raw materials may contribute
significantly to the total raw waste load. These sources
can be controlled or eliminated by containing them and
attempting recovery and reuse or disposal in a non liquid
manner.
The following list of spill prevention and control
techniques that are commonly found throughout the liquid
handling industries and apply equally well to the organic
chemicals industry:
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1. Diked areas around storage tanks.
For flammable substances these are required; however, as
a passive barrier to tank rupture, and tank and pipe
connection leaks, a diked tank storage area is
considered the first-line barrier to containing and
reducing the spread of large-volume spills.
2. Tank level indicators and alarms.
The sounding of alarms at prescribed levels during tank
filling could be expected to minimize the common
occurrence of overflow when reliance is on manual
gauging for control.
3. Above-ground transfer lines.
Above-ground installation permits rapid detection of
pipeline failures and minimizes hazardous polluting
substances from polluting ground waters. Although
increasing the possible mobility into surface waters,
long-term considerations are believed to favor above-
ground transfer lines.
4. Curbed process areas.
Spills from processing equipment must often be removed
rapidly from the area but prevented from spreading
widely in the immediate area; consequently, curbed areas
connected to collecting sewers are indicated.
5. Area catchment basins or slop tanks.
For containment of small spills and leaks in the
immediate area thereby effecting removal at the highest
concentrations, local catchment basins can provide
significant flexibility in preventing spills from
entering water courses.
6. Holding lagoons for general plant area.
Lagoons which can be used to segregate spills and
prevent them from passing as slugs into waste water
treatment plant or water courses, give the surge
capabilities necessary for handling large volume or
highly toxic spills.
7. Initial waste water treatment.
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.For treatment of floating substances or for the chemical
neutralization or destruction of spilled materials, the
initial waste water treatment plants serve to ameliorate
the more drastic effects of spills in receiving waters.
8. Availability of spill cleanup equipment.
Vacuum trucks, booms, neutralizing chemicals and other
similar equipment represent obvious contingency planning
to cope with spills.
9. Routine preventative maintenance schedule.
10. Spill control plan.
The formalization of a plan for coping with spills and
the training of personnel in courses of action similar
to plant safety programs is a highly desirable approach
of coping with spills in a manner which would avoid
entry into water courses and sewers thereby avoiding the
disruption of waste water treatment facilities.
The application of ancillary control techniques requires
judicious planning of operational philosophy, organization,
and specific management and control measures.
Operational Philosophy
Each plant management needs to formulate a "Spill Exposure
Index" which will reveal potentially-serious problems in
connection with its operation. Once the problems are
defined, remedies and the costs of implementing them are not
difficult to determine. The next step is establishing
priorities, a budget, and a commitment to capital and
operating expenditures. As new production projects are
proposed for a plant site, each should incorporate adequate
measures for spill prevention as an integral part of its
design. Capital investment in this category should be
considered to be important as an investment in process
equipment or, alternatively, in more elaborate waste water
handling procedures.
One approach is the development of a classification index
(taking into consideration the minimum aquatic biological
toxicity, and effect on waste treatment plant performance)
which establishes ratings of hazardous polluting substances
and recommends the minimum acceptable containment measures.
Organization
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Since most of the prevention and control measures represent
added inconvenience and costs in the eyes of the plant
operating staff, even when wholeheartedly accepted,
establishment of an independent group, with a direct
assignment to minimize spills and authorized to take action,
is especially desirable.
Specific Measures
In a facility with a "high spill exposure index" there
should be a review of the designs and conditions to
determine the potential consequences of spills and leaks in
an objective manner. The review should consider the design
of the process and equipment and should involve a piece-by-
piece physical inspection. In common with most successful
projects, there is no substitute for careful attention to
details. All possible accidents and departures from routine
should be considered and then analyzed in terms of the
hazard and the corrective action or control measures which
could be applied.
All plant facilities need to be included, both process and
service units. A number of potential sources of leaks and
spills can frequently be eliminated without real
inconvenience to the process.
In the process area, a number of spill exposure conditions
are often found. One of the most serious is limited storage
between coupled process units which may not be in balanced
operation. Intermediate storage of this type is most often
designed on the basis of surge volume provided. But often
operating rates are difficult to adjust, and overflow of the
surge tank results. When spill prevention per se becomes an
important criterion, a major revision in standard operating
procedure, and perhaps a revised standard for the size of
storage may be called for. Small leaks at shafts of pumps,
agitators, and valve stems are frequently tolerated; and in
the case of rotating equipment, is desirable for shaft
lubrication and cooling. In the aggregate, such losses may
be significant spills and should be prevented or contained.
Sampling stations and procedures should also be reviewed to
curtail unnecessary discard of small quantities of process
fluids. Vent systems are potential points of accidental
spill and, on hot service, may allow a continuous spill due
to vaporization and condensation.
The major hazard in storage areas is catastrophic failure of
the tank, an accident which on economic grounds alone
justifies careful attention to tank design, maintenance and
inspection. Containment of a large spill is desirably
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provided by diking or curbing, but these systems need
analysis as to proper operation both in standby status and
in the event of a spill; safety principles and operating
convenience can both be in conflict with spill prevention
and the differences must be reconciled. Venting and tank
overflow problems can be severe because of the cyclic nature
of storage operations; accessories such as heating or
cooling systems, agitators, instrumentation, and fire
prevention control systems all can represent potential for
spill.
Loading, unloading, and transfer operations are particularly
accident prone. Where materials with obviously high hazard
are involved, a high degree of reliability of the transfer
system is achievable at a cost which is reasonable. This
reliability can be achieved by provision of adequate
equipment but also in large measure by strict adherence to
well thought out procedures. Carelessness and shortcuts in
operation can often occur. The same philosophy applied to
less dangerous materials can be fruitful. Permanent piping,
swing joint systems and flexible hoses can be used
successfully for transfer and each has its place. Each has
inspection and maintenance problems as well. The design of
transfer lines must consider such questions as leaving them
full or empty when idle, purging before and after use,
protection with check valves, and manifolding. Multiple use
of a transfer line should be avoided but when necessary on
economic or other grounds the design should provide a clear
indication to the operator that valves are properly set.
Remote setting of valves, and panel indication of valve
position are practical systems that could be more widely
employed.
The emphasis on in-plant pollution control technology must
be based equally on adequate, well-maintained equipment and
on operational vigilance and supervision. Attention to
tnese details will often result in reducing significantly
not only the total loads on waste water treatment plants
but, most importantly, reducing the variability of pollutant
flows with a concomitant improvement in the quality of
treated waste waters emitted to receiving bodies.
£nd-of-Pipe Treatment
Because of tJae scarcity of treatment plant performance data,
it was determined to be reasonable to combine the Phase. I
and II treatment technology data for this study. A summary
of the types of treatment technology which were observed
during both phases is listed in Table 7-1. During the Phase
XI study, 70 individual plants were surveyed; however, 6 of
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Table 7-1
Organic Chemicals Study
Treatment Technology Survey
Type of Treatment or Disposal Facility Number of Plants Observed
Phase IPhase II
Activated Sludge 7 9
Activated Sludge-aerated lagoon 2 0
Activated Sludge-polishing pond 0 1
Activated Sludge-solar evaporation pond 0 1
Trickling Filter-activated sludge 1 0
Aerated lagoon-settling pond 3 1
Aerated lagoon-no solids separation 2 1
Facultative Anaerobic lagoon 4 4
Stripping Tower 1 1
No current treatment - 37
system in planning stage
To Municipal Treatment Plant 5 23
Deep-well disposal 2 6
Physical Treatment, e.g., API Separator 4 3
Activated Carbon 0 6
Incineration 0 1
TOTAL 34 64
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the 70 plants were previously surveyed during the Phase I
study. Table 7-1 has been prepared taking this duplication
into consideration. Of the plants surveyed in Phase II
which are subcategorized in A, B, C, or D over 80 percent
provide their own waste treatment facilities, while 60
percent of the Subcategory D plants discharge to municipally
owned treatment facilities.
A description of the treatment technologies that may be used
with the wastes from this industry is first presented
followed by data obtained in the Phase I and Phase II
surveys.
Waste water treatment technology in the organic chemicals
industry relies heavily upon the use of biological treatment
methods. These are supplemented by appropriate initial
treatment to insure that proper conditions, especially by pH
controls and equalization, are present in the feed to the
biological system.
JnitiaJ. treatment for the removal of solids is not routinely
required in the industry and is installed on a selective
basis where the quantity of solids would interfere with
subsequent treatment. The initial step in waste water
treatment is often equalization basins for control of pH.
Consequently, the disposal of sludges or solids from this
initial treatment step is not the same type of problem as
encountered in municipal sewage systems.
Technologies for removal of pollutants from water have been
investigated for many years. The technologies that appear
applicable to the waste waters of this industry are
identified in the following paragraphs.
There are many variations of the basic activated sludge
process that can be used with success. There are also many
variations of treatment system operation that can be
incorporated to assist in meeting effluent limits and there
are many approaches to upgrading existing systems when they
fail to perform effectively. Specific plants in this
industry have modified their operation and design to achieve
better performance. Reports on such modifications can be
noted in the literature. Manuals to improve the design and
performance of treatment systems are available from the
Environmental Protection Agency. The available design,
operational and upgrading techniques are within the
capability of the organic chemicals industry to consider and
apply.
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Oil Removal
For those waste waters having significant quantities of oil,
gravity separators are particularly useful. The API
separator is the most widely used gravity separator. The
basic design is a long rectangular basin, with enough
detention time for most of the oil to float to the surface
and be removed. Most API separators are divided into more
than one bay to maintain laminar flow within the separator,
making the separator more effective. API separators are
usually equipped with scrapers to move the oil to the
downstream end of the separator where the oil is collected
in a slotted pipe or on a drum. On their return to the
upstream end, the scrapers travel along the bottom moving
the solids to a collection trough. Any sludge which settles
can be dewatered and either incinerated or disposed of as
landfill.
The gravity separator usually consists of a pre-separator
(grit chamber) and a main separator, usually rectangular in
shape, provided with influent and effluent flow distribution
and stilling devices and with oil skimming and sludge
collection equipment. It is essential that the velocity
distribution of the approach flow be as uniform as possible
before reaching the inlet distribution baffle.
Anotner type of separator that has been used in refineries
is the parallel plate separator. The separator chamber is
subdivided by parallel plates set at a 45° angle, less than
six inches apart. This increases the collection area while
decreasing the overall size of the unit. As the water flows
through the separator, the oil droplets coalesce on the
underside of the plates and travel upwards where the oil is
collected. The parallel plate separator can be used as the
primary gravity separator, or following an API separator.
If the effluent from the gravity separators is not of
sufficient quality to insure effective treatment before
entering the biological or physical-chemical treatment
system, other processes such as clarifiers and dissolved air
flotation units may be used to reduce the oil and solids
concentration.
Clarifiers use gravitational sedimentation to remove oil and
solids from a waste water stream. Often it is necessary to
use chemical coagulants such as alum or lime to aid the
sedimentation process. These clarifiers are usually
equipped with a skimmer to remove any floating oil.
Clarifiers used after a biological system normally do not
have skimmers as there should be no floating oils at that
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point. The sludge from the clarifiers is usually treated
before final disposal.
Dissolved Air Flotation (DAF)
These systems are used to remove suspended material with a
specific gravity close to that of water. The dissolved air
system generates a supersaturated solution of waste water
and air by pressurizing waste water and introducing
compressed air, then mixing the two in a detention tank.
This "supersaturated" waste water flows to a large flotation
tank where the pressure is released, thereby generating
numerous small air bubbles which effect the flotation of the
suspended organic material by one of three mechanisms: 1)
adhesion of the air bubbles to the particles of matter; 2)
trapping of the air bubbles in the floe structure of
suspended material as the bubbles rise; and 3) adsorption of
the air bubbles as the floe structure is formed from the
suspended organic matter. In most cases, bottom sludge
removal facilities are also provided.
There are three process alternatives that differ by the
proportion of the waste water stream that is pressurized and
into which the compressed air is mixed. In the total
pressurization process, the entire waste water stream is
raised to full pressure for compressed air injection.
In partial pressurization only a part of the waste water
stream, either a portion of the influent or recycled
effluent, is raised to the pressure of the compressed air
for subsequent mixing. If a sidestream of influent is
pressurized, the pumping required in the system is reduced.
In the recycle pressurization process, treated effluent from
the flotation tank is recycled and pressurized for mixing
with the compressed air and then, at the point of pressure
release, is mixed with the influent waste water. Operating
costs may vary slightly, but performance should be
essentially equal among the alternatives.
Improved performance of the air flotation system is achieved
by coagulation of the suspended matter prior to treatment.
This is done by pH adjustment or the addition of coagulant
chemicals, or both. Aluminum sulfate, iron sulfate, lime,
and polyelectrolytes are used as coagulants in the raw
waste. These chemicals are essentially totally removed in
the dissolved air unit, thereby adding little or no load to
the downstream waste treatment systems. However, the
resulting float and sludge may become a less desirable raw
material for recycling as a result of chemical coagulation
addition. A slow paddle mix will improve coagulation. One
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of tne manufacturers of dissolved air flotation equipment
indicated a 60 percent suspended solids removal and 80 to 90
percent grease removal without the addition of chemicals.
With the addition of 300 to 400 mg/1 of inorganic coagulants
and a slow mix to coagulate the organic matter, the
manufacturer indicated that 90 percent or more of the
suspended solids and more than 90 percent of the grease can
be removed. Total nitrogen reduction between 35 and 70
percent was found in dissolved air units surveyed in the
meat packing industry.
The reliability of the dissolved air flotation process and
of the equipment is well established. The usefulness of the
dissolved air process can be realized by proper installation
and operation. The feed rate and process conditions must be
maintained at the proper levels at all times to assure this
reliability. This fact is not always understood, and thus
full benefit is frequently not achieved.
Anaerobic Processes
The high concentrations of organic matter in the waste
waters from this industry make these wastes suited to
anaerobic treatment. Anaerobic or facultative
microorganisms, which function in the absence of dissolved
oxygen, break down the organic wastes to intermediates such
as organic acids and alcohols. Methane bacteria then
convert the intermediates primarily to carbon dioxide and
methane. Much of the organic nitrogen present in the
influent is converted to ammonia nitrogen. If sulfur
compounds are present, hydrogen sulfide will be generated.
Acid conditions are undesirable because methane formation is
suppressed and noxious odors develop. Anaerobic processes
are economical because they provide high overall removal of
BODJD with low power cost and low land requirements. Two
types of anaerobic processes that may be used are the
anaerobic lagoon and the anaerobic filter.
Anaerobic lagoons are not widely used in this industry but
could be used as the first step in a secondary treatment
sequence. BOD removal efficiencies of over 50 percent
generally can be achieved in the lagoons. These lagoons are
relatively deep (3 to 5 meters, or about 10 to 17 feet), low
surface area systems with typical waste loadings of 240 to
320 kg BOD5/1,000 cubic meters (15 to 20 Ib BOD5/1,000 cubic
feet) and detention times of five to ten days. A scum layer
may be allowed to accumulate on the surface of the lagoon to
retard heat ioss, to ensure anaerobic conditions, and
hopefully to retain obnoxious odors. Plastic covers of
nylon-reinforced Hypalon, polyvinyl chloride, and styrofoam
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have been used on occasion to reduce heat loss. The waste
water flow inlet should be located near, but not on, the
joottom of the lagoon. In some installations, sludge is
recycled to ensure adequate anaerobic seed for the influent.
The outlet from the lagoon should be located to prevent
short circuiting of the flow and carry-over of the scum
layer.
For best operation, the pH should be between 7.0 and 8.5.
At a lower pH, methane-forming bacteria will not survive,
the acid formers will predominate and the system will not
perform effectively. At a high pH (above 8.5), acid-forming
bacteria will be suppressed and lower the lagoon efficiency.
Advantages of an anaerobic lagoon system are initial low
cost, ease of operation, and the ability to handle shock
waste loads, and a consistent quality effluent.
Disadvantages of an anaerobic lagoon are the hydrogen
sulfide generated from sulfate-containing waters and the
increased ammonia concentrations in the effluent. If acid
conditions develop, severe odor problems result. Anaerobic
lagoons used as the first stage in secondary treatment are
usually followed by aerobic units. Anaerobic lagoons are
not permitted in some states or areas where the ground water
is high or the soil conditions are adverse (e.g., too
porous), or because of odor problems.
The anaerobic filter represents the newest anaerobic
treatment process. The unit is useful for the treatment of
dilute soluble wastes and in denitrifying oxidized effluents
for nitrogen control. The filter consists of a bed of
submerged media through which waste flows in an upward
direction. The anaerobic organisms grow within the bed and
either cling to the media or grow in the voids. The filter
aas a large capacity for retaining microorganisms. Of the
types of media that have been tested, one-inch rounded
stones appear to be the best.
wastes with COD concentrations of over 750 mg/1 appear well
suited for this process. COD removal efficiencies of 90+
percent have been obtained with hydraulic detention times
greater than 18 hr and with wastes having COD concentrations
up to 2,000 mg/1.
The microorganisms remain in the filter for a long time,
even though the hydraulic retention time is short. No
solids recycle is incorporated in the anaerobic filter. The
filter responds to changing waste loads and has been
indicated to operate well on a periodic basis.
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Difficulties will be encountered with wastes that will clog
the filter media and therefore high solids wastes are not
appropriate unless solids removal precedes the anaerobic
filter. The wastes must have adequate alkalinity to buffer
any pH reduction during treatment. Initial start up of an
anaerobic filter should be done carefully to establish the
proper organisms. Once the methane organisms are
established, oxidized conditions should not be permitted to
occur in the filter.
Aerobic Lagoons
Aerobic lagoons (stabilization lagoons or oxidation ponds)
are large surface area, shallow lagoons, usually 1 to 2.3
meters (3 to 8 feet) deep, loaded at a BOD5 rate of 20 to 50
pounds per acre. Detention times vary from about one month
to six or seven months; thus, aerobic lagoons require large
areas of land.
Aerobic lagoons serve three main functions in waste
reduction:
Allow solids to settle out;
Equalize and control flow;
Permit stabilization of organic matter by aerobic
and facultative microorganisms.
If the pond is deep, 1.8 to 2.4 meters (6 to 8 feet), the
waste water near the bottom may be void of dissolved oxygen
and anaerobic organisms may be present. Therefore, settled
solids can be decomposed into inert and soluble organic
matter by aerobic, anaerobic, or facultative organisms,
depending upon the lagoon conditions. The soluble organic
matter is also decomposed by microorganisms. It is
essential to maintain aerobic conditions in at least the
upper six to twelve inches in shallow lagoons, since aerobic
microorganisms cause the most complete removal of organic
matter. Wind action assists in carrying the upper layer of
liquid (aerated by air-water interface and photosynthesis)
into the deeper portions. The anaerobic decomposition
generally occurring in the bottom converts solids to liquid
organics, which can become nutrients for the aerobic
organisms in the upper zone.
Algae growth is common in aerobic lagoons. This currently
is a drawback when aerobic lagoons are used for final
treatment because the algae appear as suspended solids and
contribute BOD_5. Algae added to receiving waters are thus
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considered a pollutant. Algae in the effluent may be
reduced by drawing off the lagoon effluent at least 30 cm
(about 14 inches) below the surface, where concentrations
are usually lower, maintenance cleaning of the lagoon,
installation of a "polishing" clarifier or combination of
these actions. Algae in the lagoon, however, play an
important role an stabilization. They use CO2f sulfates,
nitrates, phosphates, water and sunlight to synthesize their
own organic cellular matter and give off oxygen. The oxygen
may then be used by other microorganisms for their metabolic
processes.
The effluent quality of a lagoon system can be affected
adversely during certain periods of the year by the algae
generated in the lagoons. The quantity of algae in the
lagoon effluent can be variable and result in difficulties
in meeting the effluent limitations. These algae can settle
out in the bottom of a receiving stream or lake, undergo
death and degradation, exert an oxygen demand in effluent
samples and in the stream, and will be measured as part of
the solids in the effluent.
There are, however, a variety of approaches that can be used
to control the quantity of solids in the effluent. Most of
these approaches either are in use or have been demonstrated
to the point that they can be used where needed. Under
specific design and operational conditions, each approach
can Joe economical. The more applicable approaches include
microstraining, coalgulation-flocculation, land disposal,
granular media or intermittent sand filtrations, and
chemical control.
Microstrainers have been used successfully in numerous
applications for the removal of algae and other suspended
material from water. In a series of nine investigations
over a period of years, an average removal of 89 percent of
net plankton was observed. Microstraining requires little
maintenance and can have practical application for the
removal of algae from stabilization ponds or lagoons on an
as needed basis.
Coagulation-flocculation, followed by sedimentation, has
been applied extensively for the removal of suspended and
colloidal material from water. Coagulation-flocculation
requires competent operating personnel and adequate disposal
of the sludge that will be produced.
Land disposal for all or a portion of the lagoons effluent
during periods when the effluent limitations are not being
met can be a feasible approach. The effluent limitations
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are in mass units, thus a reduction in outflow to a stream
during periods of high algae content may compensate for the
increased solids concentrations and permit the mass
limitations to be attained. Spray irrigation in a
controlled manner onto adjacent land can be accomplished
without additional environmental problems.
In filtration, the suspended material is removed by physical
screening, sedimentation, and inter particle action. For
separation of algae cells from lagoon effluents, granular
media filtration can be economic and produce a satisfactory
effluent.
Chemical measures for the control of excessive algae growths
in lagoons are dependent upon the type, magnitude, and
frequency of growth, the local conditions, and the degree of
control that is necessary.
.Recommended chemicals have included copper sulfate for algal
control. Additional chemicals have been used with varying
success. Recommendations usually should be directed to the
specific problem within a specific body of water. For
maximum effectiveness, algal control measures should be
undertaken before the development of the algal bloom.
Thus, there are many alternatives that can be used for algae
control and/or removal to assure that the lagoon effluent
quality meets the described limitations. The approach of
choice at a specific location will be a function of land
availability, available operating personnel, degree of
difficulty in meeting the limitations, and overall waste
management economics.
Ice and snow cover in winter reduces the overall
effectiveness of aerobic lagoons by reducing algae activity,
preventing mixing, and preventing reaeration by wind action
and diffusion. This cover, if present for an extended
period, can result in anaerobic conditions. The adverse
effects of this condition can be substantially overcome by
supplemental aeration using submerged aerators. When there
is no ice and snow cover on large aerobic lagoons, high
winds can develop a wave action that can damage dikes.
Riprap, segmented lagoons, and finger dikes are used to
prevent wave damage. Finger dikes, when arranged
appropriately, also prevent short circuiting of the waste
water through the lagoon. Rodent and weed control, and dike
maintenance are all essential for good operation of the
lagoons.
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Advantages of aerobic lagoons are that they reduce the
suspended solids and colloidal matter, and oxidize the
organic matter of the influent to the lagoon. They also
permit flow control and waste water storage. Disadvantages
are reduced effectiveness during winter months that may
require supplemental aeration, increase design capacity, and
require possible provisions for no discharge for periods of
three months or more. In addition, there are relatively
large land requirements, the potential algae growth problem
leading to higher suspended solids, and odor problems for a
short time in spring, after the ice melts and before the
lagoon becomes aerobic again.
Aerobic lagoons usually are the last stage in secondary
treatment and frequently follow anaerobic or anaerobic-plus-
aerated lagoons. Large aerobic lagoons allow plants to
store waste waters for discharge during periods of high flow
in the receiving body of water or for irrigation purposes
during the summer. These lagoons are popular in rural areas
where land is available and relatively inexpensive.
Aerated Lagoons
The aerated lagoon is a smaller, deeper aerobic pond
equipped with mechanical aerators or diffused air units.
The addition of oxygen enables the aerated lagoon to have a
higher concentration of microbes than the oxidation pond.
The retention time in aerated lagoons is usually shorter,
between three and ten days. Many aerated lagoons are
operated without final clarification. As a result,
biological solids are discharged in the effluent, causing
toe effluent to have high BODJ5 and solids concentrations.
As the effluent standards become more strict, final
clarification will be increasing in use.
Aerated lagoons use either fixed mechanical turbine-type
aerators, floating propeller-type aerators, or a diffused
air system for supplying oxygen to the waste water. The
lagoons usually are 2.4 to 4.6 meters (8 to 15 feet) deep,
and have a detention time ranging from hours to days. BOD5_
reductions in completely mixed aerated lagoons may range
from 40 to 60 percent, with little or no reduction in
suspended solids. Because of this, aerated lagoons are
compared to extended aeration units without sludge recycle.
Advantages of this system are that it can rapidly add
dissolved oxygen (DO) to meet the oxygen demand, provides
BOI/5 reduction, and requires a relatively small amount of
land. Disadvantages include the power requirements and the
fact that the aerated lagoon, in itself, usually does not
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reduce tfODjj and suspended solids adequately to be used as
the final stage in a high performance secondary system.
Activated Sludge
Controlled biological treatment using activated sludge or
one of its modifications can be used to treat the wastes
from the organic chemicals industry. In the conventional
activated sludge process, recycled biologically active
sludge or floe is mixed in aerated tanks or basins with
waste water. The microorganisms in the floe adsorb organic
matter from the wastes and convert it by oxidation-enzyme
systems to such stable products as carbon dioxide, water,
and sometimes nitrates and sulfates or nitrogen gas
(denitrification). The detention time required for adequate
waste stabilization depends on the type of waste and its
concentration, but the average time is about six hours. The
floe, which is a mixture of microorganisms (bacteria,
protozoa, and filamentous types), acquired waste, and inert
fractions, can assimilate organic matter rapidly when
properly active; hence, the name activated sludge. Oxygen
is introduced by mechanical aerators, diffused air systems,
or other means.
From the aeration tank, the mixed sludge and waste water, in
which little nitrification generally has taken place, are
discharged to a sedimentation tank. Here the sludge
settles, producing a clear effluent, low in BODJ5, and a
settled biologically active sludge. A portion of the
settled sludge, normally about 20-25 percent, is recycled to
serve as an inoculum and to maintain a high mixed liquor
suspended solids content. Excess sludge is removed (wasted)
from the system to thickeners and anaerobic digestion, to
chemical treatment and dewatering by filtration or
centrifugation, or to land disposal where it is used as
fertilizer and soil conditioner to aid secondary crop
growth.
This conventional activated sludge process can reduce BODJ5
and suspended solids up to 95 percent. However, it cannot
readily handle shock loads and widely varying flows and
therefore might require upstream flow equalization.
Although the microorganisms remove almost all of the organic
matter from the waste being treated, much of the converted
organic matter remains in the system in the form of
microbial cells. These cells have a relatively high rate of
oxygen demand and must be removed from the treated waste
water before discharge. Thus, final sedimentation and
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recirculation of biological solids are important elements in
an activated sludge system.
Sludge is wasted on a continuous basis at a relatively low
rate to prevent build-up of excess activated sludge in the
aeration tank. Shock organic loads usually result in an
overloaded system and poor sludge settling characteristics.
Effective performance of activated sludge facilities
requires pretreatment to remove inhibiting material.
Equalization also is useful to prevent shock loadings from
upsetting the aeration basin. Because of the high rate and
degree of organic stabilization possible with activated
sludge, application of this process to the treatment of
organic chemicals waste waters has been receiving increasing
attention.
Many variations of the activated sludge process are
currently in use. Examples include: the tapered aeration
process, which has greater air addition at the influent
where the oxygen demand is the highest; step aeration, which
introduces the influent waste water along the length of the
aeration tank; and contact stabilization. The contact
stabilization process is useful where the oxygen demand is
in the suspended or colloidal form. The completely mixed
activated sludge plant uses large mechanical mixers to mix
the influent with the contents of the aeration basin,
decreasing the possibility of upsets due to shock loadings.
Tne Pasveer or oxidation ditch is a variation of the
completely mixed activated sludge process that is widely
used in Europe. In this process, horizontal cage rotors are
used to provide aeration and mixing in a narrow oval ditch.
The activated sludge process has several disadvantages.
Because of the amount of mechanical equipment involved, its
operating and maintenance costs are higher than other
biological systems such as aerated lagoons or aerobic ponds.
The small volume of the aeration basin makes the process
more subject to upsets than either oxidation ponds or
aerated lagoons.
The activated sludge process is capable of achieving very
low concentrations of BOD5, COD TSS, and oil, dependent upon
the influent waste loading and the particular design basis.
Reported efficiencies for BODfj removal are in the range of
80 to 99 percent.
Filtration
A variety of filters can be used to remove the solids in a
treated waste water: intermittent sand filters, slow sand
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filters, rapid sand filters and mixed media filters. BOD5
removal occurs primarily as a function of the degree of
solids removal. The effluent from the sand filter is of
high quality. A summary of available information indicates
that effluent suspended solids concentrations of less than
10 mg/1 can be met. Although the performance of a sand
filter is well known and documented, it is not in common use
in the organic chemical industry because use of refinements
of this type has not been needed to reach current waste
water standards.
Waste water filtration technology has been applied to
biological treatment effluents for some time but with
greater rapidity in the past decade. Major use has been
with municipal waste waters but it has also been used for
industrial waste waters. A chemical plant in England used
sand filtration for effluent solids reduction prior to 1960.
Filtration has been applied to biologically treated waste
waters in the petroleum refining industry. A full scale
mixed media filtration system is presently operating at the
Marathon Oil Company, Robinson, Illinois. Review of the
self-reporting data from the facility after installation of
the filters and after 20 months of operation indicated the
following removal efficiencies by the filter: BOD-22X, TSS-
72%. The average concentration of BOD and TSS applied to
tne filters was 12.3 and 42 mg/1 respectively.
Knowledge of waste water filtration technology has
progressed to the point that design manuals and information
are readily available. There is ample reason to believe
that waste water filtration can be applied to the
biologically treated wastes from the organic chemicals
industry.
A slow sand filter is a specially prepared bed of sand or
other mineral fines on which doses of waste water are
intermittently applied and from which effluent is removed by
an under-drainage system.
It removes solids primarily at the surface of the filter.
The rapid sand filter is operated to allow a deeper
penetration of suspended solids into the sand bed and
thereby achieve solids removal through a greater cross
section of the bed. The rate of filtration of the rapid
filter is up to 100 times that of the slow sand filter.
Thus, the rapid sand filter requires substantially less area
than the slow sand filter; however, the cycle time averages
about 24 hours in comparison with cycles of up to 30 to 60
days for a slow sand filter. The larger area required for
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the latter means a higher first cost. For small plants, the
slow sand filter can be used as tertiary treatment:. The
rapid sand filter can be applied following secondary
treatment. If a rapid sand filter were used as secondary
treatment, it would tend to clog quickly and require
frequent backwashing, resulting in a high water use. This
wash would also need treatment prior to discharge
particularly if the rapid sand filter were used in secondary
treatment applications with only conventional solids removal
upstream in the plant. Thus its use generally occurs after
secondary treatment.
The rapid sand filters operate essentially unattended with
pressure loss controls and piping installed for automatic
backwashing. They are contained in concrete structures or
in steel tanks.
In a rapid sand filter, as much as 80 percent of the head
loss can occur in the upper few inches of the filter. One
approach to increase the effective filter depth is the use
of more than one media in the filter. Other filter media
have included coarse coal, heavy garnet or ilmenite media,
and sand. There is no one mixed media design which will be
optimum for all waste water filtration problems.
Although a mixed media filter can tolerate higher suspended
solids loadings than can other filtration processes, it
still has an upper limit of applied suspended solids at
which economically long runs can be maintained. With
activated sludge effluent suspended solids loadings of up to
120 mg/1, filter runs of 15-24 hour at 5 gpm/ft* have been
maintained when operating to a terminal head loss of 15 feet
of water.
The effluent quality produced by plain filtration of
secondary effluents is essentially independent of filter
rate within the range of 5-15 gpm/ft primarily due to the
high strength of the biological floe. The following quality
of filter effluents is presented as general guides to the
suspended solids concentration which might be achieved when
filtering a secondary effluent of reasonable quality,
without chemical coagulation: high rate trickling filter,
10-20 mg/1, two stage trickling filter, 6-15 mg/1,
contract srablization, 6-15 mg/1, conventional activated
sludge plant, 3-10 mg/1, and activated sludge plant with a
load factor less than 0.15, 1-5 mg/1.
The slow sand filter has been in use for 50 years and more.
It has been particularly well suited to small cities and
isolated treatment systems serving hotels, motels,
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hospitals, etc., where treatment of low flow is required and
land and sand are available. Treatment in these
applications has been of sanitary or municipal-type raw
waste. Rapid sand filters have received most attention as
the principal method to treat water supplies. More
recently, applications as a tertiary treatment mode for
municipal and joint municipal-industrial waste water
facilities have proven successfuly. Multi-media filters
were developed for general use in the mid 1960's. These
filters also have been used for potable water treatment and
tertiary treatment of waste water since that time.
The reliability of all principal types of filters seems to
be well established. When the sand filter is operated
intermittently, there should be little danger of resultant
discharge of untreated effluent or poor quality effluent.
The need for bed cleaning becomes evident with the reduction
in quality of the effluent or in the increased cycle time,
both of which are subject to monitoring and control.
With larger sized slow sand filters, the labor in
maintaining and cleaning the surface should receive adequate
consideration. Cleaning of the rapid sand filter requires
bacJcwashing of the bed of sand. Backwashing is an effective
cleaning procedure and the only constraint is to minimize
the washwater required in backwashing, since this must be
disposed of in an appropriate manner other than discharging
a stream. Chlorination, both before and after sand
filtration, particularly in the use of rapid filters may be
desirable to minimize or eliminate potential odor problems
and slimes that may cause clogging.
The rapid sand filter has been used extensively in water
treatment plants. Its use ir, tertiary treatment of
secondary treated effluents appears to be a practical method
of reducing BOD5 and suspended solids to levels below those
expected from conventional secondary treatment.
Carbon Adsorption
Activated carbon can be used to reduce the pollutional load
of many kinds of waste waters. It is particularly well
suited for removal of various dissolved organic materials.
Most but not all dissolved organics can be adsorbed by
carbon. The exact degree of removal from the liquid phase
depends upon a number of factors. An important aspect of
carbon adsorption is its capability of removing organics
which are not completely removed by conventional biological
treatment. Since some biodegradable organics are also
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adsorbable, carbon can be used in either of two ways: to
upgrade or to replace conventional biological treatment.
Carbon removes dissolved organics through the action of two
distinctly different mechanisms. The first is adsorption,
which removes the dissolved organics from solution. Organic
molecules in solution are drawn to the porous surface of the
carbon granule by inter-molecular attraction forces, where
the organics become substrates for biological activity.
Biodegradation is thus the second mechanism by which carbon
improves water quality. Adsorption is the principal
mechanism by which the dissolved organics are removed from
solution. Adsorption is probably predominant when a carbon
column is first put into service. As operation proceeds,
however, the biological process grows in importance as the
numbers of microorganisms increase.
Waste water treatment with activated carbon involves two
major and separate process operations. The water is
contacted with the carbon by passing it through a vessel
filled either with carbon granules or with a carbon slurry.
Impurities are removed from the water by adsorption when
sufficient contact time is provided. The carbon system
usually consists of a number of columns or basins used as
contactors. These are connected to a regeneration system.
After a period of use, the carbon adsorptive capacity is
exhausted. The carbon must then be taken out of service and
regenerated thermally by combustion of the organic
adsorbate. Fresh carbon is routinely added to the system to
replace that lost during hydraulic transport and
regeneration. These losses include both attrition due to
pnysical deterioration and burning during the actual
regeneration process.
The activated carbon process utilizes granular or powdered
activated carbon to adsorb pollutants from waste water. The
adsorption is a function of the molecular size and polarity
of the adsorbed substance. Activated carbon preferentially
adsorbs large organic molecules that are non polar.
Tne function of activated carbon is the removal of dissolved
organics. However, while many organics are adsorbed, those
molecules which are small or highly polar are not readily
captured. Methanol, formic acid, or sugars, for example,
are not easily adsorbed. Such readily biodegradable organic
chemicals can be removed by biological treatment. Where
such chemicals are in the waste water, activated carbon
should be used after biological treatment. An important
aspect of carbon adsorption is its capability of removing
314
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organics which are not completely removed by conventional
biological treatment.
Unless the suspended solids content of the waste water to be
treated is low, prehaps less than 50-65 mg/1, it is
advisable to employ dual-media filtration, chemical
coagulation, or other particulate removal techniques before
applying the waste water to the carbon bed. Activated
carbon is too expensive to be used primarily as a filter
medium. Thus an activated carbon unit frequently follows a
solids removal process, usually a sand filter which prevents
plugging of the carbon pores. From the filter, the water
can flow to a bank of carbon columns arranged in series or
parallel. As the water flows through the columns the
pollutants are adsorbed by the carbon, gradually filling the
pores. At intervals, portions of the carbon are removed to
a furnace where the adsorbed substances are burnt off. The
regenerated carbon is reused in the columns, with some
makeup added, because of handling and efficiency losses.
Detailed evaluation of carbon adsorption as a possible waste
water treatment technology began in 1960-61 as part of the
mandate of Congress (PL 87-88) to investigate advanced waste
treatment technology.
In recent years, many carbon adsorption applications have
been evaluated on a full scale. These include granular
activated carbon, powdered activated carbon, carbon
adsorption as the entire waste water treatment process,
carbon added to existing activated sludge systems, and
carbon adsorption following biological treatment. The
latter appears to be the most applicable for the wastes from
the organic chemicals industry. Activated carbon technology
has been demonstrated and shown to be feasible in a number
of applications of granular activated carbon systems
currently in use by industry.
Process designs for carbon adsorption systems are readily
available from consultants and equipment manufacturers.
Process design procedures are available in the literature
and a design manual is available from the Environmental
Protection Agency. Several of the companies producing
organic chemicals have subsidiaries or components that have
developed significant practical experience on carbon
adsorption and are attempting to market that experience by
providing services to other industries in the treatment of
their wastes.
The effluent quality obtainable from granular carbon
treatment depends on the character of the waste water being
315
-------
treated. Therefore, in documenting the probable effluent
quality of carbon plants, the nature of the raw waste water
and the type of pretreatment is important.
Other Technology
Among the available waste water treatment technologies, the
following have reached a reasonable stage of development
and/or can be transferred from other industries when their
unique capabilities are required.
316
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Ammonia Stripping
The removal of ammonia from alkaline solution is the major
potential application for air stripping. Although the
process has been demonstrated in moderately large
operations, its selection will depend upon the nature of the
waste waters and requirements for the removal of nitrogenous
substances. Scale formation in equipment, typical of a
cooling tower configuration, can cause operational problems
or demand close control of the chemistry of the system. In
addition, air stripping of ammonia is temperature sensitive,
proceeding at slow rates at low temperatures. The stripped
substances are usually in such low concentrations that they
are not considered to be air pollutants.
Chemical Oxidation
Chemicals such as chlorine, permanganate, hypochlorite, and
ozone may be used to chemically oxidize some pollutants.
Breakpoint chlorination for destruction of ammonia in
treated waters from municipal sewage plants has long been
recognized and ozone has been used for the treatment of
potable water. The application of oxidative chemicals
requires that specific determination be made of their
effectiveness in removing the pollutants, and in particular,
to determine if the reaction products are innocuous. As a
particular example, the chloramines produced by chlorine and
ammonia are more toxic to aquatic life than the ammonia.
Similarly, the toxic aspects of the chemicals must be
carefully evaluated to insure that the removal of one type
of pollution does not result in creating a different or,
perhaps, even more severe pollution problem. It is expected
that chemical oxidation will be employed on a highly
selective basis such as in the destruction of cyanide where
its overall effectiveness is assured.
Foam Separation
Surfactants added to a waste water followed by air diffused
in the liquid to produce a foam can effect the concentration
of various substances often found in waste waters. However,
successful development above the pilot plant scale has not
been demonstrated and its usefulness as a treatment
technology will be limited.
Algal Systems
Nutrient removal by the growing of algae is well known;
however, it has not achieved any significant acceptance due
317
-------
primarily to (1) the necessity of having a relatively warm
climate with high incidence of sunshine and (2) the
difficulties of removing the algae from the waste water
before discharge.
Incineration
Destruction of pollutants by combustion or incineration is
technically feasible regardless of the concentration insofar
as the products of combustion do not create an air pollution
problem. At the present time, incineration of concentrated
liquid wastes containing phenolic compounds is being
practiced. Equipment is available for achieving
incineration of virtually any type of waste; however, the
use of supplementary fuel is usually required. Incineration
is not frequently used because of the high cost of energy.
In some instances where the removal of pollutants cannot be
achieved in a less costly manner or because disposal of the
removed pollutants still presents a severe problem,
incineration may be an appropriate method of water pollution
control
Wet Air Oxidation
The oxidation of organic pollutants by introducing air or
oxygen into water under pressures of from 300 to 1800 psig
has been primarily used for the destruction of sludges. For
the oxidation to proceed autogenously, it is necessary that
a sufficient concentration of oxidizable substances be
present to provide the exothermic energy necessary to
maintain the required temperatures. Partial oxidation of
concentrated biological streams such as the sludges from
initial and biological treatment results in a stabilized
solid which can be used as a soil conditioner. Wet air
oxidation will continue to be considered primarily for the
destruction of concentrated pollutants such as slurries or
sludges.
Liquid-Liquid Extraction
The transfer of mass between two immiscible phases, known as
liquid-liquid extraction, is often capable of achieving high
degrees of removal and recovery of selected components. The
technology has been well developed in the chemical and
nuclear fuel industries but has been infrequently applied to
the treatment of waste water streams. Liquid-liquid
extraction would be employed to remove a relatively valuable
component or a particular noxious substance from a waste
water stream prior to additional treatment. A typical
example is the recovery of phenolic compounds. Loss of the
318
-------
extracting liquid to the water stream must be considered
since it may then be a pollutant which requires further
removal before discharge of the treated waste water.
Ion-Exchange
The removal of ions from water by the use of ion-exchange
resans has been well established in the field of water
treatment. Man-made resins or naturally occurring minerals
such as zeolites or clinoptilolite have been used. The
removal of zinc from viscose rayon wastes by ion-exchange
has been demonstrated; however, successful long-time
operation has not been achieved. Ion exchange has been used
for the removal of nitrates, and clinoptilolite has been
shown to be effective in the removal of ammonium ion from
waste waters. Although ion exchange can be an effective
method for the removal of ionic species from waters, the
economic necessity for regeneration of the ion-exchange
media results in a concentrated liquid stream for which
further disposal must be considered. The use of ion
exchange in waste water treatment would be limited to the
selective removal or concentration of pollutants for which
more economically effective methods are not available.
Since ion-exchange regenerates added mass to the waste
stream from the regeneration, ultimate disposal of
concentrated streams from ion-exchange systems will contain
more total dissolved solids than removed from the waste
waters.
Reverse Osmosis
Desalination research and development efforts have been
responsible for the development of reverse osmosis as a
method for removal of ionic species from waste waters.
Nonionic species also can be removed; however, control of
membrane fouling must be given special consideration. The
major process advantage of reverse osmosis is its low energy
demand when compared with evaporation and electrodialysis;
however, the costs of replacement membranes may be an
offsetting factor to the total cost picture. The
applicability of reverse osmosis to the treatment of waste
water streams can only be determined by laboratory and pilot
plant tests on the waste water of concern. As in the case
of ion exchange, reverse osmosis produces a concentrated
stream containing the removed pollutants and further con-
sideration must be given to its disposal.
Evaporation
319
-------
Evaporation has been well developed and widely used for the
desalination of seawater. Furthermore, it is a well
developed operation in the chemical process industries.
Direct evaporation is the most energy consuming of the water
removal processes; therefore, elaborate multi-stage systems
are required to effect energy economy. Its application to
the concentration of selected waste water streams is
established; however, evaporation is usually used in
conjunction with other process operations where the energy
demands and resulting concentrated solutions can be
justified on the basis of most economic overall performance.
This approach can be expected to continue in the face of
rising energy costs and increasingly stringent limitations
on waste water discharges. The technical feasibility of
evaporation will have to be determined for specific
situations since a highly concentrated waste water may cause
fouling of heat transfer substances. Also, volatile species
which can be removed by the steam stripping action and,
consequently, appear in the condensate would mean further
treatment before reuse or discharge. The disposal of highly
concentrated streams of pollutants must be considered.
Electrodialysis
Developed for the desalination of water, electrodialysis is
a separation technique that would be expected to compete
with ion exchange, reverse osmosis, freezing and evaporation
for the removal of pollutants from waste water streams. As
in the case of all of these, electrodialysis for waste water
treatment must be chosen on the basis of achieving the
necessary performance under required operating conditions.
PLANT SURVEY PROGRAM
Single-stage Biological Treatment
During the plant survey program, historic waste water
treatment plant performance data were obtained when
available. The data were statistically analyzed, and, when
possible, the individual plant performance was evaluated
with respect to the original design basis. Subsequent to
this evaluation, a group of plants was selected as being
exemplary in performance as indicated by effectiveness of
BODj> removal. These particular exemplary plants are
indicated in Table 7-2, which is a summary of all of the
historic performance data made available by industry for the
purposes of the study. The amount of analytical data used
in the statistical analyses are indicated in the "data base
column" of Table 7-2. The following is a summary of the
average reductions capable of exemplary treatment plants:
320
-------
Table 7-2
Historic Treatment Plant Performance
50% Probability of Occurrence
COD
BOD
TOC
SS
Data Base
Plant
No.
11
21.2
31
41
51.2
6
7
81
9'
101
,,1.2
12
13
14
15
16'
171
18
19'
201
Exemplary
Exemp la ry
Treatment
System
AL
AS-AL
AS
AS
TF-AS
AL
AL
AL
AS
AS
AS-AL
AS
AS
AS
AL
AS
AS
AS
AS
AS
Plant Average
Single Stage
Category °i
D
C
D
B
B
B-C
C
B
C
B
C
A-B
B-C
B
D
D
D
D
C
>
Plants - Average
i Removal
75
96.4
63
64.2
73.5
~
-
-
-
74.5
-
85
—
—
—
—
67
25.4
-
~
74
69
Effluent
320
470
200
120
83
~
165
75
-
80
-
97
610
—
226
—
1 ,760
1,520
--
296
378
% Removal
97
-
93.5
-
—
~
--
-
83
90.1
99.7
-
—
73
-
82.5
—
63.6
97.6
98.8
93
92
Effluent „. D , Effluent
,. % Removal ,,
10
„
16
15
-
291
9.9
23.5
152 60 170
20
20 97 100
59
294 — 295
410 42 780
63
362
—
303
157
46.9
82.2 79 135
60
o/ „ i Effluent
% Remova 1 , ,
—
163
55
—
-
665
81
24.3
130
-
-370 145
..
189
280
-
289
_.
480
-
„
134
-
Durat i on
(months)
6(Sept-Feb)
12
12
14
14
12
12
12
7(Aug-Feb)
12
12
12
14
14
6(July-Dec)
S(Aug-Mar)
6(June-Oct)
12
5(June-Sept)
5 (June-Sept)
Performance
Pe r i od
dai ly average
dai ly average
monthly average
monthly average
monthly average
weekly average
monthly average
monthly average
dai ly average
weekly average
dai ly average
monthly average
monthly average
monthly average
weekly average
monthly average
dai ly average
weekly average
monthly average
weekly average
Plants considered to be exemplary in performance.
Multiple-stage biological treatment.
^Plant 16 is not included in average.
-------
Table 7-3
Treatment Plant Survey Data
Plant No.
11
o 13
^ 162
172
18
192
202
21
22
23
Average
1
AS-AL
AS
AS
TF-AS
AL
AL
AS
AS-AL
AS
AS
AS
AS
AS
AS
AL
AS
AS
B
B-C
COD
% Removal
64
71
57
59
66
69
75
94
65
54.8
60.0
77.3
22.1
59.5
96.2
62
16.1
95.^
72
Effluent
mg/L
2,300
284
214
133
980
92
595
337
940
1 ,650
1 ,400
1 ,000
2,680
5,100
317
600
1 ,370
147
Total
% Remova 1
90
73
82
92
73
84
92
99
90
82.1
81.4
90.0
16.7
69.8
99.5
78
47.5
92.6
87
BOD
Effluent
mg/L
427
74
13
12
235
6
75
16
177
300
240
310
650
1 ,800
19
27
210
41
TOC
% Removal
mg/L
32
71
35
43
1 1
26
69
27
64
80.8
63.4
76.8
-
55.8
96.6
66
8.3
95.4
58
Effluent
mg/L
2,710
132
80
61
573
52
242
343
470
280
410
360
1 ,025
1 ,700
114
47
550
35
TSS
% Removal
Negative
Negative
40
97
Negat i ve
99
Negative
Negat i ve
120
43.6
Negative
42.9
Negat i ve
Negat i ve
89
53.4
Negat i ve
Effluent
mg/L
4,700
62
14
44
362
3
50
145
338
552
1 ,300
732
1 ,170
2,500
100
30
82
37
TDS
Effluent
mg/L
2,300
3,100
2,900
1 ,430
3,000
690
3,810
2,690
1 ,520
10,990
3,750
4,060
2,050
8,360
1,950
9,800
15,400
580
Oi 1 £- Grease
Effluent
mg/L
-
13
43
23
113
-
,23
,3
63
2264
22k
1064
-
194
-
<.034
21*
Based on 24 hrs composite samples.
^Plants considered to be exemplary in performance based on historical data.
.Oil and grease are reported as carbon tetachloride extractables.
Oil and grease are reported as Freon extractables.
-"Includes exemplary plants as well as Plant 23.
-------
COD BOD TOC Effluent
Removal Removal Removal TSS
percent percent percent mg/1
Exemplary Single- and
Multiple-Stage Plants 74 93 79 134
Exemplary Single-stage
Plants 69 92 60 65
Major differences in performance data were observed for TOC
removals because only two historic data points were
available.
During the survey program, 24-hour composite samples were
obtained in order to verify the plant historic performance
data, as well as to provide a more complete waste water
analytical profile. These results are presented in Table 7-
3. The following is a summary of the average reductions
capable of being attained by exemplary treatment as verified
by composite sampling:
COD BOD TOC
Removal Removal Removal
percent percent percent
Exemplary Treatment Plants 72 87 58
The results of the composite sampling program compared well
with the historic data, thus, verifying the historic plant
information. The TOC(removal of 58 percent would seem to
substantiate the lower value of 60 percent as previously
indicated (Table 7-2). As indicated by the TSS removal
data, 9 of the 17 plants surveyed had negative TSS removal.
Over 75 percent of the plants had inadequate solids handling
facilities.
There are very wide variations in the suspended solids data
obtained in the verification sampling (Table 7-3). These
variations are beyond the normal variations experienced at
well designed and operated biological treatment plants. A
major problem was that the biological sludge in many
facilities is not wasted, thereby increasing TSS effluent
levels. Unless one is thoroughly familiar with the
operation of the particular plant surveyed, it is difficult
to interpret TSS data, much less use it to set effluent
limits. For this reason, recommendations concerning TSS for
the technology levels BATEA and BADCT were based on the
performance experience of adequately designed units
functioning in other industries.
323
-------
Multiple-Stage Biological Treatment
During the course of the plant surveys, three plants were
observed to have multiple-stage biological treatment. Plant
5 (see Table 7-2) required two-stage treatment for phenol
removal, while Plants 2 and 11 required it because of
relatively high raw waste loads and rigid water quality
criteria. Multiple biological treatment is being used in
the industry and can achieve high pollutant removals. The
Phase I recommendation that biological treatment be
considered BPCTCA is further substantiated by the Phase II
survey data.
Performance of Industry Treatment Systems
As part of the survey conducted for this phase of the
industry, no waste water treatment technology was found that
was unique to the organic chemicals industry. The
application of end-of-pipeline waste water treatment
technology throughout the industry includes similar
operational steps. The waste water treatment technology
presently used in the industry is generally applicable
across all industry subcategories.
End-of-pipe treatment technology is based upon well
established methods, such as biological treatment, which can
be carried out in various types of equipment and under a
wide variety of operating conditions. The treatment systems
for the organic chemicals industry can be affected by
intermittent, highly concentrated waste loads due to the
nature of certain pollutant generating operations or to
inadvertent spills and leaks. The effective control methods
for such intermittent loads are to prevent their occurence
or provide sufficient volumetric capacity in equalization
basins to ameliorate their effect.
A combination of methods may be used depending upon the
nature of the process operations, safety requirements (such
as the dumping of reactors to prevent runway reactions and
possible explosions), and the availability of land area for
the construction of equalization basins. For presently-
operating plants, the most practical solution is the
installation of an equalization basin of sufficient volume
and residence time to insure that any "slugs" of pollutants
can be mixed into larger volumes. This will usually
guarantee that concentration levels are lowered to the point
where the operability of the ensuing treatment step, usually
the biological system, will not be overly affected unless
the pollutants are highly toxic to the microorganisms.
324
-------
The importance of equalization prior to biological treatment
cannot be overstressed when the potential exists for large
variations in either flow or concentrations of waste waters.
Equalization basin design may vary from simple basins, which
prevent short circuiting of inlet waste waters to the basin
outlet going into the waste water treatment plant, to
basins which are equipped with mixers to insure rapid and
even mixing of influent waste water flows with the basin
volume. In either case, the operability and reliability of
an equalization basin should be high with minimal
expenditure of operating labor and power. The results are
well-designed and well-operated equalization basins that
insure that the subsequent treatment steps, especially those
steps sensitive to fluctuating conditions (i.e., biological
treatment), are not confronted with widely varying
conditions which may drastically affecc overall performance.
The operability, reliability and consistency of biological
waste water treatment systems are subject to a host of
variables. Some of the most important are the nature and
variability of both the flow and the waste water
composition. The best overall performance of biological
treatment systems is realized when the highest consistency
of flow and waste water composition occurs. While it must
be recognized that no waste water stream can be expected to
have constant flow at constant composition, it is possible
to insure that these effects are ameliorated by equalization
basins. Equalization, coupled with attention to such items
as the possible occurrence of chemicals toxic to
microorganisms, is the basis for achieving the maximum
potential in operability, reliability, and consistency of
biological systems. Although in-line instrumentation such
as pH, dissolved oxygen and total organic carbon analyzers
are available, their usage, except for pH and, infrequently,
dissolved oxygen, for in-line control is minimal. The
reliability of some in-line instrumentation for control has
not been developed to a degree where it is frequently used.
Control of the biological waste water treatment process
relies principally on adequate designs and judicious
attention to the physical aspects of the plant. Well-
trained, conscientious operators are most important in
achieving the maximum potential reliability and consistency
in biological treatment plants.
Achieving a high degree of operability and consistency in a
waste water treatment plant is contingent upon the
application of good process design considerations and an
effective maintenance program. The most important factor is
the incorporation of dual pieces of equipment where
historical experience indicates that high maintenance or
325
-------
equipment, modification is apt to occur. Although the
highest degree of performance reliability would be achieved
by installing two independent waste water treatment
facilities, each capable of handling the entire waste water
load, practical installations and operating costs as well as
the well-demonstrated operability of waste treatment plants,
indicate that a judicious blend of parallelism, surge
capacity, and spare equipment are the major factors to be
considered. Some of the most critical parameters that
should be incorporated in the design of waste water
treatment for the organic chemicals industry are as follows:
1. Provision for surge capacities in equalization
basins or special receiving basins to permit repair and
maintenance of equipment.
2. Installation of excess treatment capacity or
provisions for rapidly overcoming effects which may
destroy or drastically reduce the performance of
biologically based treatment systems.
3. Installation of spare equipment, such as pumps and
compressors, or multiple units, such as surface
aerators, so that operations can be continued at either
full or reduced capacity.
4. Layout of equipment and selection of equipment for
ease of maintenance.
Filtration
Supplemental organic pollutant and solids removal is being
practiced within the industry in one particular case using a
polishing pond. One major problem during summer periods is
algal blooms which, if unchecked, can drastically increase
the TSS and COD of the polishing pond effluent. In
addition, the acreage requirements of this system limit its
potential uniform application.
As described earlier, filtration can do an excellent job of
removing particulate matter from the effluent of biological
treatment systems. Where appropriate technology, such as
filtration, is not routinely used in the industry and hence,
operaring treatment plant data is not available, the
following approaches would be used in deciding whether
filtration technology was appropriate for consideration: (a)
utilize performance data from waste water treatment
situations where filtration had been used, (b) attempt to
obtain reasonable estimates using samples of biological
326
-------
treatment plant effluent, or (c) a combination of these
options. The combination option was investigated.
To quantify the effectiveness of effluent filtration for
this industry, the following steps were taken. First, the
existing literature and data on filtration of effluents from
biological waste treatment plants were reviewed to ascertain
the general performance that could be expected. Second,
samples of the effluents from biological treatment plants
treating organic chemical waste waters were tested using
laboratory filter tests to see if the results of such tests
appeared reasonable as compared to the results from other
situations described in the literature. The results are
presented in Table 7-4. Average percent COD, BOD, and TOG
removals associated with filtration are 20, 17, and 20,
respectively. Comparison of the laboratory and literature
data revealed that filtration was a feasible technology for
this industry.
Carbon Adsorption
Granular activated carbon technology is continuously being
developed and is beginning to compete actively with
biological treatment as a viable treatment alternative or as
a biological treatment effluent polishing process for some
industrial wastes. This technology has been applied to the
waste of the organic chemicals industry. The technology has
been used with other waste waters and has been demonstrated
at the pilot plant and full scale plant levels. To identify
whether carbon adsorption can be used with the waste waters
from this industry, plants using activated carbon were
surveyed and carbon adsorption isotherms were run on the
effluent from biological waste treatment plants treating
organic chemical industry wastes.
During the plant survey program, 6 activated carbon plants
treating raw waste waters were surveyed, and the results are
presented in Table 7-5. The most interesting fact is that
domestic waste water treatment experience indicates that
efficient treatment is provided with contact times between
10 and 50 minutes, while the design contact times in Table
7-5 vary between 22 and 660 minutes (calculated on an empty
column basis). These higher contact times are required
because of the much higher raw waste loads generated by
industry.
The major problems encountered in trying to compare design
criteria and present performance of carbon plants are as
follows:
327
-------
Table 7-4
Effectiveness of Filtration Tests on
Biological Treatment Plant Effluents
Plant
3
15
15
14
9
9
13
4
24
12
21
16
25
20
35
26
27
18
17
19
Average of selected data
Average of all data
Percent Removal
COD
9
87
85
24
11
10
32
None
8
21
3
84.3
39.3
8.5
51.4
26.2
***
86.8
88.4
33.3
data 20
42
BOD
4
56
*
28
None
None
36
None
2
None
None
57.8
**
17.2
***
71.4
12.5
72.1
55.6
***
17
26
38****
TOC
3
78
82
14
5
17
8
None
20
7
8
75.9
39.4
33.0
27 .7
41.2
25.0
90.6
91.6
66.0
20
37
Average does not include plants 15, 16, 17, 18, and 26, since these plants have
excessively high effluent TSS. These high effluent TSS values are the result of
poor performance of the final clarifiers. The purpose of the filtration tests
was to quantify the effectiveness of filtration on typical effluents from a
properly designed and operated biological plant, the data from atypical
effluents are excluded.
* Error in control BOD value
** No initial BOD determination.
*** Data not available.
****Average of samples excluding indeterminate answers.
328
-------
1. In most cases, design loadings, both organic and
hydraulic, have not yet been attained. This means
the new plants are sometimes grossly under-loaded.
2. Thermal carbon regeneration is presently an art
which is acquired only with actual operating
experience. For this reason, start-up problems are
often extended, and it is not unusual for the
pollutant concentrations of the activated carbon
effluent to be higher than the design value. This
situation continues until the carbon is regenerated
thoroughly.
3. Plants with insufficient spill protection and/or
inadequate housekeeping practices may discharge
specific low molecular weight hydrocarbons which
are not amenable to adsorption. This situation
results in an erratic plant performance.
The carbon adsorption isotherm is widely used to screen the
applicability of different activated carbons, to calculate
theoretical exhaustion rates, and determine if carbon
adsorption technology can be applied to specific waste
waters. The comparison of isotherm and design exhaustion
rates for Plant 29 in Table 7-5 further substantiates the
fact that isotherm data are preliminary and should not be
used for design purposes. However, carbon isotherm data do
indicate relative amenability of the particular waste water
to treatment by carbon adsorption and to identify reasonable
removal efficiencies. In addition, several existing plants
in this and other industries use carbon in combination with
activated sludge systems for industrial waste treatment.
To investigate the possibility of using activated carbon
technology on the effluents from biological treatment plants
treating organic chemical waste waters, series of carbon
isotherms were run at standard conditions using a contact
time of 30 minutes. The results of the isotherms are
presented in Tables 7-6 and 7-7. BOD carbon isotherm data
performed on the biological treatment plant effluents
yielded only two usable data points. Average performance
values are presented hereafter. Table 7-8 contains TOC and
COD carbon exhaustion data from a recent survey made of
plants in this and other industries.
329
-------
Table 7-5
Organic Chemical Plants Using
Activated Carbon to Treat Raw Wastewaters
Plant
28
29
30
31
32
33
Removal Ef f iciencies-%
Pretreatment Design Present
Solids Removal and Polyol-11
Equalization 9-hr
detention time
Equalization 150- TOC-94 TOC -89
day detention time
Equalization, Neu- Phenol-89 Phenol-94
tral ization and
solids removal
Equalization and TOC-91
Neut ra 1 i zat ion
Equalization and Phenoi-99.9 Phenol-95
Neut ra 1 i zat i on
Equalization, Neu- Color-90
tral i zat ion and
solids removal
Hydraulic Loading
Flows-gpd gpm/sq.ft. Contact Time-minutes Carbon Exhaustion Rate
Design Present Design Present Design Present Design
100,000 55,000 5.6 3.0 22 40 0.4 lb^j>olyol
Ib. carbon
20,000 7,000 0,49 0.17 540 1,550 0.07 Ib. TOC
Ib. carbon
750,000 500,000 4.6 3.1 69 104 .028 ib. phenol
Ib. carbon
30,000 20,000 660 912
72,000 22,000 2.0 0.6 215 75
800,000 7.7 27 5.4 Ibs. color
Ib. carbon
1 sotherm
0.19 Ib. TOC
Ib. carbon
-------
Table 7-6
Summary COD Carbon Isotherm Data
(Performed on Biological Treatment Plant Effluent)
Carbon Exhaustion Rate
Plant No.
lit
15
15
3
9
9
13
13
4
2k
12
21
16
20
26
. Q
23
07
17
Average1
Ibs COD Removed
Ib Carbon
0.035
0.8
0.2
1.35
0.30
0.36
0.42
0.36
0.51
0.34
^. 5
0.11
.12
4.0
.1+5
.069
0.094
.41
Ibs Carbon
1 ,000 qal 'ons
232
8.9
28.6
1.87
13.9
13.3
10.6
12.6
2.2
32.2
0.27
21 .4
29.5
.25
2.0
3.9
44.3
15.7
Max. Soluble
COD Removal (%)
22
87
87
87
7^
84
79
75
70
57
69
87
3
50.2
C7 R
41.6
42 4
72.8
83 4
63.6
on L.
93.9
69.0
Category
B
D
C
B-C
B
B
B
C
D
C
B-C
A
D
B
D
The average does not include Plants No. 12, I1*, 20 and 21.
331
-------
Table 7-7
Summary TOC Carbon Isotherm Data
(Performed on Biological Treatment Plant Effluent)
to
Plant
16
25
20
35
26
18
23
27
17
19
Influent TOC
(soluble)
mg/L
87
43
28
34
20
104
6
148
Effluent TOC
(Soluble)
mg/L
58
5
12
4
2
19
3
20
TOC
Removal
%
33.4
88.4
37.2
88.3
90.0
81.6
50.0
86.6
Carbon Exhaustion
Ibs. TOC Removed
Ib. Carbon
—
.01
—
.13
1.35
.0036
—
—
.0485
Ibs. Carbon
1,000 gal
—
35.9
—
2.25
.12
241
—
—
25.4
Average
1
87
,063
21.77
Average includes Plant Nos. 17, 25, and 35.
-------
Table 7-8
Summary of TOC and COD Carbon Exhaustion Rate
Wastewater Practical
TOC Carbon Exhaustion Rate Influent Effluent
Plant Pounds Per 1,000 Gallons* Concentration(TOC) Objective
A
B
C
D
E
F
F
OJ
**•
LJ G
H
I
J
Mean
Standard
Deviation
1.8
2.1
1.9
6.2
14.0
4.5
8.4
4.6
3.6
9.2
5.6
3.9
18
22
186
100
200
19
105
82
60
114
91
65
3
2
37
15
6
2
15
3
5
9
10
11
%TOC Removal
@
Objective
83
90
80
85
97
89
86
96
92
92
89
6
COD Carbon Exhaustion Wastewater Practical % COD Removal
Exhaustion Rate Pounds Influent con- Effluent @
Per 1000 Gallons* centration(COD)Objective Objective
3.5
2.0
11.8
9.7
5.6
2.4
4.4
2.6
7.3
18.8
6.8
5.3
47
75
520
275
405
50
290
220
190
215
229
154
<10
<10
22
10
35
•CIO
<10
17
60
<:10
19
16
>89
>87
96
96
91
>80
>96
92
68
>95
89
9
*Mim'mum theoretical exhaustion rate based on use of two-stage fixed bed contacting system.
-------
Soluble
Pollutant
Parameter Carbon Exhaustion Rate Removal
Ibs removed/lb carbon percent
COD 0.41 69
BOD 0.03 89
TOC 0.06 87
Inspection of the specific data in Tables 7-6 through 7-8
indicates that carbon adsorption has varying degrees of
amenability with regard to cost effective waste water
treatment. However, the data does indicate that
biologically treated waste waters from the organic chemicals
industry are readily treatable using activated carbon.
Following identification of the feasibility, typical design
data for carbon adsorption systems were used to establish
the design of model BAT treatment systems for costing
purposes. The laboratory data were not used to establish
the design. The actual design data are identified in
Chapter IX.
BPCTCA Treatment Systems
The review of the industry historic treatment plant data was
to quantify BPCTCA reduction factors, which would then be
applied to BPCTCA raw waste load values for each subcategory
in order to generate recommended effluent limitation. Based
on the previous discussions of biological treatment, the
following pollutant reduction factors are considered
achievable with BPCTCA treatment technology:
Percent Reduction Factors Minimum Average
Applied to Average BPCTCA Effluent Concentration
Parameter Range Average mg/1
BOD1 83-99 93 20
COD 74
TSS 30
IControlling Parameter
The BPCTCA effluent discharge recommendations are made only
for BOD and TSS.
To evaluate the economic effects of the BPCTCA effluent
limitations on the organic chemicals industry, it was
necessary to formulate a BPCTCA treatment model. The model
selected was single stage activated sludge. (See Figure 7-
1.) It is recognized that specific industry plants may
choose other biological treatment systems to meet the BPCTCA
limitations. Since it is impossible to anticipate the cost
v
334
-------
O
(0
1)
I.
in
ID
u
a.
to
335
-------
Figure 1-2
BATEA Waste Treatment Model
RIOLOtlCAL TREAT1ENT j i
-cxh
**•
RACR MSN
HOLDINC TANK
PLWT EFFLUENT
FILTER INLET
Kll
K—-n..^,,..]
"T^Tfe^giia
TtS^
FILTER UTER
HOLDINC TtNK
t~
•—(XH
«—OO-
DUAL
CMVITf FILTERS
•O*-
URBON coium
FEED PIMPS
RACK IASH
PWS
RECENERATEO CARRON
STtRACE TANK
PLANT EFFLUENT
PULSED
RED
CARRON
coium
TRANSFER
TANK
NTINC TMR
tj
.
I I Mf STOItCE TNW
T
L
SCMI FEEKR
KCUEMTIM FMMCI
OIENCH TANK
VIRCIN
CARHN
STORACI
-------
of every possible treatment system that could be used, a
common system was chosen, single stage activated sludge.
Tne model serves the function of representing a maximum
effluent treatment cost which might actually be
significantly lower due to in-process modifications or other
methods of effluent treatment.
BATEA Treatment Systems
Based on the previous performance data from multiple-stage
biological treatment plants, existing carbon treatment
plants and various carbon isotherms, it has been possible to
formulate waste reduction factors commensurate as BATEA
treatment technology:
Percent Reduction Factors
Applied to BPCTCA Minimum Average
Parameter Effluent Limitation Effluent Concentration
BOD 89 10
COD 69 50
TSS 15
The BATEA effluent discharge limitations will have two
controlling parameters, i.e., BOD and COD. The major
emphasis, however, should be on COD removal since the major
portion of the carbonaceous oxygen demanding materials
should have been removed with BPCTCA technology.
The BATEA treatment model used for economic evaluation of
the proposed limitations includes the BPCTCA treatment model
followed by dual media filtration and carbon adsorption. A
typical flow diagram is shown in Figure 7-2. The BATEA
design basis and the unit sizing criteria are discussed in
the Phase 1 study. The carbon regeneration facilities were
sized using 0.41 Ib COD removed/lb carbon, which is the
average result as determined from the carbon isotherm data.
BADCT Treatment Systems
Based on the previous filtration data, it has been possible
to formulate waste reduction factors commensurate as BADCT
treatment technology:
337
-------
Percent Reduction Factors Minimum
Applied to BPCTCA Average Effluent
Parameter Effluent Limitation Concentration
mg/1
BOD 17
COD 20
TSS 15
The BADCT treatment model used for economic evaluation of
the proposed limitations includes the BPCTCA treatment model
followed by dual media filtration.
Although dual media filtration of biologically treated
wastewaters has not been practiced on a plant scale in this
industry, at least one other industry, the petroleum
refining industry, does successfully employ this technology.
However, rather than adopt performance requirements based on
results obtained in other industries, the removals of
pollutants observed in the laboratory filtration tests were
used to establish removal factors.
filtration
>
Laboratory experiments were conducted with the recognition
that results were not actual operating data, but rather that
the results would allow a comparison to be made with
existing data resulting from filtration of other
biologically treated effluents. The laboratory experiments
therefore did provide reasonable results, as compared to
data in the literature. In adopting filtration as an
appropriate technology for this industry in the above
manner, the judgement was made that such technology has been
adequately demonstrated, if not routinely applied.
In using the average removals from the laboratory filtration
studies to establish the BADCT limitations, a conservative
approach was taken. Available data from other situations
indicates that higher percent removals can be achieved. In
determining the average percent removals (Table 7-4),
certain data were not included (plants 15, 16, 17, 18, and
26) because it was felt that the data from these plants
would bias the results, i.e., could indicate higher results
than otherwise might occur. If all of the data had been
used the average percent removals would have been: COD 42%;
BOD 26*; and TOG 31%. These removals are about double those
chosen as representative.
338
-------
In choosing the values that were used as indicative of the
results of filtration, reasonable conservative percent
removals were chosen. Such a choice used the best available
technical judgement and an evaluation of results obtained by
filtration in other waste water situations. Reliance was
not placed solely on the laboratory filtration tests.
339
-------
-------
SECTION VIII
COST, ENERGY AND NONWATER QUALITY ASPECTS
Cost
Tiiis section provides quantitative cost information relative
to assessing the economic impact of the proposed effluent
limitations on the organic chemicals industry. In order to
evaluate the economic impact on a uniform treatment basis,
end-of-pipe treatment models were proposed which will
provide the desired level of treatment as follows:
Technology Level Treatment Model
BPCTCA Single-stage Activated Sludge.
BADCT Activated Sludge and Filtration.
BATEA Activated Sludge, Filtration, and
Carbon Adsorption.
The method used to attain the effluent limitations whether
through in-plant controls or by end-of-pipe treatment is
left up to the individual manufacturer as to which is the
most attractive economically.
Extensive annual and capital cost estimates were prepared
for numerous end-of-pipe treatment models, which were
presented in the Phase 1 study. As an expedient, these cost
estimates were linearly extrapolated to include the similar
Pnase 2 treatment models.
The capital and annual cost for BPCTCA, BATEA and New
Sources are presented in Table 8-1 for each product/process
segment. It is noted that these costs reflect treatment of
wastes from a single product plant situation. The relevant
flow and production rates are also included in Table 8-1 for
each situation. These rates were based upon those which are
typical for each process.
These costs are presented with the understanding that most
plants in this industry are multi-product plants which treat
a mixture of waste waters. Thus, in some cases, costs are
larger than actual costs for the multi-product plant due to
economies of scale. In evaluating the economic impact of
the costs of treatment, the costs presented in Table 8-1 may
need to be adjusted to account for the economy of scale for
the particular plant's actual flow.
341
-------
Table 8-1
ORGANIC CHEMICALS INDUSTRY (PHASE II)
ECONOMICS SUMMARY
(All Costs Shown Are Cumulative Totals)
Cumene
Para-Xy lene
BTX Aromatlcs
Chlorotoluene.
Chloromethanes
Chlorobenzene
D i pheny 1 ami ne
Perchloroethylene
Phthal ic Anhydride
Tri cresyl Phosphate
Methyl ethyl Ketone
Hexane thy 1 ened i ami ne
Hexarethy t ened I ami ne
Adi poni tai le
Benzoic Acid
Methylchloride
Maleic Anhydr ide
Ethyl Acetate
Propyl Acetate
Oxalic Acid
Fornic Acid
OJ Cyclohexanone Oxime
•^ 1 sopropanol
Cal ci U.TI Stearate
Hexane thy lene let ram me
Hydraz 1 ne
Isobutylene
Sel -Butyl Alcohol
Acryloni trt 1 e
Synthetic Cresols
Caprolactam
Para-Ani nophenol
Propylene Oxide
Pentaerythr itol
Sacchar i n
Ortho-Ni troani 1 i ne
Para-tJ i troani 1 i ne
Pentachlorophenol
Fatty Acids
Fatty Acid Derivatives
lonone & Methyl lonone
Methyl Sal icylate
Misc. Batch Chemicals
Cltronellol & Gerantol
Plasticizers
Dyes & Dye Intermediates
Toner Pi gments
Lake Pigments
Citric Acid
Naphthenic Acid
Monosodium Glutamate
Tanntc Acid
Vanillin
Pro-
ducti on
Lbs/Oav
822,000
550,000
1 ,041 ,000
30,000
356,000
300,000
100,000
50,000
342,000
50,000
274,000
548,000
548,000
548,000
164,000
82,000
137,000
503,000
197,000
500 ooo
27,400
50,000
150,000
1 ,370.000
80,000
22,000
6,000
137,000
218,000
658,000
50,000
685,000
50,000
548,000
68,500
25,000
50,000
65,000
50,000
150,000
150,000
600
10,000
1,000,000
1 ,400
50,000
10,000
10,000
10,000
100,000
22,000
33,000
55,000
10,000
Waste-
Water
Gal/Dav
33
2,900
5,800
436,000
120,000
1,800
6,300
32,000
24,000
168,000
43,000
66,000
72,000
642,000
56,000
118,000
38,000
78,000
28,000
330 ,000
939! ooo
1 ,710,000
40 , 000
366,000
519,000
80,000
2,300
335,000
16,400
353,000
2,000
2,390,000
75,600
4,180.000
83,800
807,000
1,610,000
305,000
16,100
504,000
116,000
675
20,800
9,450,000
1,700
3,900
1,138,000
375,000
1 ,200,000
5,720,000
99,700
246,200
661 ,000
160,730
5
Capital
Cost
Zero
383,000
454,000
953,000
583,000
386,000
411 ,000
424,000
505,000
762,000
1,660,000
3,600,000
3,350,000
10,700,000
5,640,000
1 ,670,000
.7'! ,000
539,000
RWL
RWL
1 ,410,000
RWL
$ Per
S 1000
Per Year Gal.
3,600
148,000
160,000
281 ,000
190,000
14; ,000
153,000
160,000
171,000
725,000
498,000
916,000
805,000
2,800,000
1,490,000
470,000
691 ,000
182,000
RWL
RWL
402,000
RWL
300
135
72.8
1.77
4.35
217
64.6
13.7
19.5
3.64
31.7
38.1
30.6
11.9
72.8
10.9
49.8
6.41
RWL
RWL
1.17
RWL
$ Per
1000
Lbs.
0.012
0.72
0.41
25.7
1.47
1.31
4.08
8.87
1-37
12.2
4.98
4.58
4.04
14.0
24.8
15.7
13.7
1.00
RWL
RWL
40.0
RWL
S
Capital
Cost
Zero
398,000
479,000
1 ,150,000
676,000
401,000
436,000
468,000
544,000
880,000
1 ,710,000
3,670,000
3,420,000
11 ,000,000
5,700,000
i , 760 , ooo
711 ,000
629,000
RWL
RWL
1 ,750,000
RWL
S
Per
Year
3,600
151 ,000
164,000
314,000
206,000
156,000
158,000
167,000
178,000
245,000
507,000
928,000
817,000
2,850,000
1,500,000
485,000
691 ,000
198,0/JO
RWL
RWL
467,000
RWL
S Per $ Per
1000 1000
Gal. Lbs.
300
138
74.8
1.98
4.71
237
66.4
14.3
20.3
3.97
32.3
38.6
31.1
12.1
73.3
11.3
49.8
6.94
RWL
RWL
1.36
RWL
0.012
0.73
0.50
28.8
1.59
1.42
4.19.
9.28
l.43
13.3
5.07
4.64
4.10
14.2
25.0
16.2
13.7
1.08
RWL
RWL
46.5
RWL
$
Capital
Cost
Zero
413,000
495,000
1,400,000
839,000
416,000
519,000
536,000
577,000
1,100,000
1,840,000
4,360,000
3,890,000
12,800,000
6,080,000
2,150,000
711 ,000
BADCT
RWL
RWL
2,230,000
RWL
— BATEA
$
Per
Year
3,600
1 76 , 000
193,000
383,000
257,000
182,000
171 ,000
203 ,000
222^000
308,000
530,000
1,160,000
960,000
3,780,000
1,620,000
603,000
691 ,000
BADCT
RWL
RWL
576,000
RWL
$ Per
1000
Gal.
300
162
88.8
2.41
5.88
277
72.4
17 4
i ( .*
25.3
H.99
35.0
48.2
36.5
16.1
79.1
14.0
49.8
BADCT
RWL
RWL
1.68
RWL
$ Per
1000
Lbs.
0.012
0.86
0.58
35.0
1.99
1 66
4^57
11 I
,6.f
5.50
5.81
4.82
18.9
27.0
20.2
13.7
BAOCT
RWL
57.4
RWL
SEE CAPROLACTAM
1 ,070,000
1 ,390,000
850,000
522,000
1 ,560,000
1,900,000
2,400,000
203,000
22,700,000
2,820,000
11 ,100,000
1 ,270,000
3,640,000
1 ,530,000
911,000
503,000
1,760,000
1,500,000
Zero
655,000
6,180,000
86 , 1 00
1 43 , 000
1 ,260,000
1,960,000
4,890,000
5,480,000
1,480,000
1,090,000
1,240,000
5,000,000
293,000
365,000
241 ,000
179,000
389,000
557,000
677,000
124,000
5,610,000
632,000
12,490,000
1,390,000
1,010,000
446,000
259,000
168,000
488,000
389,000
73,900
102,000
1,910,000
15,800
26,100
431 ,000
548,000
1,260,000
1 ,570,000
414,000
291 ,000
320,000
1,310,000
2.20
1.93
8.24
213
3.18
93.1
5.25
170
6.43
22.9
1.62
45.4
3.44
0.76
2.32
28.5
2.65
9.17
300
13.5
0.56
25.5
18.3
1 .04
4.00
2.88
0.75
11.4
3.24
13.3
22.2
0.62
12.0
30.0
8J.7
8.22
7.38
3.18
6.^?
22.4
32.4
12.7
55.6
111
24.7
10.9
9.2
8.91
7.06
337
2.81
5.31
30.9
1.43
118
150
43.0
51.6
24.2
15.9
359
1 ,270,000
640,000
940,000
558,000
1 ,740,000
1,950,000
2,600,000
203,000
23,200,000
2,890,000
11 ,800,000
1,270,000
3,910,000
1 ,950,000
1,110,000
546,000
2,000,000
1,610,000
Zero
908,000
7,380,000
90,700
151 ,000
1,620,000
2,160,000
5,280,000
5,650,000
1,570,000
1,240,000
1,310,000
5,110,000
328,000
408,000
256,000
185,000
420,000
565,000
715,000
124,000
5,710,000
644,000
2,630,000
1,390,000
1,060,000
522,000
293 ,000
175,000
530,000
402,000
73,900
109,000
2,150,000
16,800
27,500
395,000
583,000
1,330,000
1,740,000
429,000
317,000
332,000
i ,330,000
2.46
2.16
8.75
220
3.43
04 s
5*52
170
6.55
23.3
.1.71
45.4
3.60
0.89
2.63
29.8
2.87
9.47
300
14.3
0.63
27.0
19.4
1.19
4.26
3.04
0.83
11.8
3.52
16.2
22.5
0.69
13.5
32.0
84 5
8] 84
7 48
3:3?
6.82
22.8
33.0
13.4
55.6
116
28.6
12.3
9.59
9.65
7.29
337
2.98
5.97
32.7
1.52
135
160
364
Ve
53.4
11.3
19.4
364
1 ,730,000
2 , 1 40 , 000
1 ,290,000
574,000
2,450,000
2,530,000
6,430,000
203,000
26,800,000
3.220,000
13,600,000
1,270,000
5 ,2tO ,000
2,910,000
1,740,000
572,000
2,660,000
2,180,000
Zero
704,000
12,900,000
134,000
223,000
2,780.000
3,220,000
8,090,000
9,840,000
2,080,000
1,640,000
1,710,000
10,600,000
446,000
525,000
358,000
218,000
624,000
741,000
2,040.000
124,000
6,760,000
740,000
3.000.000
1,390,000
1,460,000
752 000
455,000
255,000
700,000
481 ,000
73,900
139,000
3,700.000
27,900
46,100
1,260,000
911,000
2,180,000
2,970.000
573,000
420,000
442,000
3.330,000
3.35
2.78
12.2
260
5.1
124
15.8
170
7-75
26.8
1.96
45.4
4.96
1 27
4. '09
43.4
3.79
11.4
300
18.3
1.08
44.8
32.4
1.91
6.66
4 °S
1.42
K o
V.'67
20.8
56.6
0.93
17.5
44.7
99-5
12.9
9.69
8.86
6.82
27.0
37.9
15.3
55.6
160
40.8
19. '2
14.0
12.7
8.75
337
3.81
10.2
54.3
2.54
217
250
81 .2
O
34'. 9
24.9
911
-------
Energy
The BPCTCA treatment, models were designed assuming sludge
dewatering using vacuum filtration with sludge cake disposal
to a sanitary landfill. An alternative sludge disposal
method is incineration, which oxidizes the sludge organics
and evaporates the water in the sludge. The remaining
inorganic ash is 10 percent of the original volume. The
offsetting factor is the substantial amount of energy
required to realize this volume reduction.
Since the previous cost tables are computed using August
1971 dollars, the recent energy crisis has not impacted on
these figures. The future availability and pricing of
energy will play an ever increasing role in the selection of
waste water treatment processes and sludge handling
alternatives.
Nonwater Quality Aspects
The major nonwater quality consideration which may be
associated with.in-process control measures is the use of
alternative means of ultimate disposal. As the process RWL
is reduced in volume, alternate disposal techniques (such as
incineration, ocean discharge, and deep-well injection) may
become feasible. Recent regulations are tending to limit
the applicability of ocean discharge and deep-well injection
because of the potential long-term detrimental effects
associated with these disposal procedures. Incineration is
a viable alternative for concentrated waste streams,
particularly those associated with Subcategory C.
Associated air pollution and the need for auxiliary fuel,
depending on the heating value of the waste, are
considerations which must be evaluated on an individual
basis for each use.
Other nonwater quality aspects, such as noise levels, will
not be perceptibly affected. Most chemical plants generate
fairly high noise levels — 85-95 dB (a) — within the
battery limits because of equipment such as pumps,
compressors, steam jets, flare stacks, etc. Equipment as-
sociated with in-process or end-of-pipe control systems
would not add significantly to these levels.
343
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SECTION IX
BEST PRACTICABLE CONTROL TECHNOLOGY
CURRENTLY AVAILABLE (BPCTCA)
The application of best practicable control technology
currently available (BPCTCA) for the secondary organic
products segment of the organic chemicals manufacturing
point source category should include the utilization of both
in-process controls as well as end-of-process treatment
technologies. The goal of these controls and technologies
is the reduction and eventual elimination of pollutants from
all discharges. These pollutants are responsible for most
of the degradation this industry presently inflicts upon the
aquatic environment. The following discussions describe the
pollution control technologies commensurate with BPCTCA and
the procedure used to establish effluent limitations
guidelines.
The nature of the specific manufacturing process will
determine the combination of process controls and
modifications which are best suited for at-source water
pollution control. However, some practices are generally
applicable to all process plants within this point source
category.
The first of these is the implementation of process
observation and sampling programs to determine the identity,
location, quantity, and composition of all aqueous streams
within the plant. Monitoring should include all aqueous
process streams as well as storage tank drainage, flare and
pump seal waters, storm runoff, and waste water associated
with support activities such as laboratories, materials
receiving and shipment, and intake waters treatment.
Although not considered as major sources of pollutants,
utility waters and steam condensate from noncontact cooling
and heating should also be included in any such survey. The
flows and loadings developed should be allocated to the
different processes in the plant in terms of production-
based ratios. This provides a clear understanding as to
which specific products require high water utilization or
generate large amounts of water-borne pollutants. At the
present time, this information has been developed by only a
very few manufacturers within this industry.
Waste characterisation studies of this type logically lead
to the selection of various streams for segregation or the
application of at-source controls. Exemplary chemical
process plants segregate all waste waters which become
345
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contaminated with organic chemical pollutants. These waste
waters include contact wastes which flow continuously from
within the process battery limits as well as intermittent
waste waters which have contacted chemicals in other
sections of the plant. The segregation and collection of
these contaminated wastes from noncontaminated streams such
as noncontact cooling waters appreciably reduce the volume
of waste water to be treated in a centralized waste water
treatment plant.
In most chemical manufacturing processes, the volume of non-
contact cooling water required is between 3 and 100 times
greater than the water which contacts chemicals within the
process. The exact ratio depends upon whether the plant
uses once-through cooling water or a recirculating system
with cooling towers. However, the quantity of pollutants
present in these waters generally is less than one percent
of that present in contact waters. The major pollutants
associated with noncontact waters are inorganic anions and
cations existing as dissolved solids and chemicals to
control slimes, algae, and corrosion. These materials do
not normally affect dissolved oxygen levels in receiving
waters.
In exemplary plants where contact waters are collected
separately from noncontact waters, it is possible to design
and operate a treatment system which has been sized to treat
the optimum hydraulic and organic pollutant loadings from
the manufacturing operations. Fluctuations in influent
concentration can be reduced by equalization of the wastes.
This practice also serves to smooth out shock loads
resulting from process upsets. Such shock loads can result
in conditions which could cause the treatment system to
perform at less than design efficiency due to hydraulic or
organic overlaods or to toxic or inhibitory conditions.
One of the most common at-source controls utilized by
organic chemical plants is the separation and selective
burning of hydrocarbon by-products. These materials are
invariably formed because very few chemical reactions are
100 percent selective in the formation of the desired
product. In almost every plant surveyed for the production
of secondary organic products, some waste organic chemicals
are disposed of by burning or hauling to landfill disposal.
Although they may not be significant on a flow volume basis,
these materials, if flammable, should not be discharged to
the sewer and if not flammable would increase the quantities
of hydrocarbons present in waste waters by an order of
magnitude if they were combined with aqueous process wastes.
346
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The devices used for burning may range from simple flares
(for materials with high vapor pressures) to complex liquid
waste incinerators or pyrolysis furnaces with extensive air
pollution control equipment. In many cases, waste organic
by-products are suitable as auxiliary boiler fuel. Although
the continuation of this practice should be evaluated to
insure that adequate air pollution control devices are
utilized, it represents a significant contribution to the
reduction of hydrocarbons present in the waste waters from
most plants surveyed. For this reason, it is considered as
one of the generally applicable in-process control practices
that should be considered for BPCTCA.
A second practice involves the separation of insoluble
organic chemicals from process waste waters. In many cases,
this can be accomplished by simple gravity separation or the
use of flotation systems. The fatty acid product/process
grouping uses this technique to advantage. Insoluble
hydrocarbon skimmings are collected and treated by
filtration and sulfuric acid addition to increase product
yields.
Process modifications consistent with BPCTCA include the
regeneration and reuse of aqueous working fluids in the
process. This is normally done by vacuum evaporation.
Typical examples include the regeneration of sulfuric acid
in processes to produce isobutylene and secondary butyl
alcohol.
Other modifications include the direct recycle of a working
aqueous fluid such as the absorbent in a gas scrubber or
water used in barometric condensers. These techniques are
utilized in the processes to manufacture benzoic acid and
hexamethylenetetramine. In these cases, the volume of
contact water discharged is reduced from a once-through
operation to tne blowdown from a recirculating system.
Because of the diverse nature of even the limited number of
processes examined in this study, it is not possible to
generalize beyond practices such as sewer segregation and
nonaqueous disposal of specific organic chemical waste water
components. For this reason, BPCTCA effluent limitations
guidelines were calculated based upon an end-of-process
treatment model. However, it is expected that the industry
will incorporate in-process controls whenever possible to
reduce waste water discharges.
End-of-process treatment technologies commensurate with
BPCTCA are based on the utilization of biological systems
such as the activated sludge process, extended aeration,
aerated lagoons, trickling filters, and anaerobic and
347
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facultative lagoons. These systems may include additional
treatment operations such as equalization, neutralization,
primary clarification with separation of insoluble material,
and nutrient addition. Final removal of suspended solids is
accomplished by clarification.
Although the activated sludge process is considered as the
treatment system most generally applicable to the wide
variety of wastes generated by this industry, it must be
recognized that many specific processes generate wastes
which, if directly treated, would be toxic or inhibitory to
a biological system accepting only those wastes. However,
most of these wastes become noninhibitory if the influent
concentrations are reduced from the extremely high values
existing in the raw waste. This has been demonstrated in
biological systems treating chlorinated hydrocarbons from
the manufacture of ethylene dichloride and vinyl chloride
and in systems which treat the combined wastes from a batch
chemical plant where the treatability of individual batch
wastes may vary widely.
BPCTCA does not preclude the use of carbon adsorption or
other types of physical/chemical treatment to achieve BPCTCA
effluent limitations guidelines if such treatment is more
appropriate or cost effective.
At the present time, most manufacturers have elected to
dispose of toxic, inhibitory, or difficult wastes by means
other than waste water treatment systems, such as by deep-
well injection or ocean dumping. The geographic location of
many plants manufacturing these materials has made this a
rather common practice. If deep-well injection or ocean
dumping were considered as viable alternatives consistent
with BPCTCA, some of the process plants surveyed would not
discharge any process wastes to receiving waters. However,
because of the potential danger of underground leakage or
contamination inherent in the practice of deep-well
disposal, effluent limitations guidelines have been
developed as if these wastes were to be treated for
discharge to surface waters.
The effluent limitations guidelines for BPCTCA were
developed using a step-wise approach starting with the
process raw waste load (RWL). The process RWL is the
production-based ratio relating pollutants to specific
products manufactured by specific processes. During the
field sampling program, the process RWL was developed for
different manufacturing operations by sampling contact
process waste waters. The RWL is the necessary link between
the wide diversity of products and manufacturing operations
348
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existing in this industry and the production-based effluent
linu.rations guidelines.
A single set of RWL values was first established for each of
the secondary product-product groups covered in Phase II of
this study. It was necessary to develop single numerical
values for flow as well as values for each of the three
waste load parameters despite the fact that field sampling
data indicated that significant variation exists between
sampling periods for a single process and between different
manufacturers operating nominally the same process.
The single set of values assigned to each process was
designated as the RWL which can be obtained through the
application of in-process pollution control practices which
are commensurate with BPCTCA. These practices were
discussed previously in this section. The actual RWL values
were indicated with each of the separate process
descriptions presented in Section IV.
It should be noted that the lowest observed values were not
arbitrarily chosen as RWL for BPCTCA. Factors such as
process plant age, size, geographic location, and method of
discharge (to surface waters or to a municipal treatment
plant) were considered when drastically differing RWL were
obtained for the same process.
There were many cases where only a single value from one
sampling period could be developed for the process, or where
the RWL varied drastically between sampling periods or
between manufacturers for no apparent reason. In such cases
it was necessary to use either the single value or the
arithmetic mean as the RWL assigned to the process.
In some of the batch or semi-batch manufacturing operations
associated with the batch and semi-continous processes
subcategory, it was not possible to develop individual RWL1s
for each of the hundreds of specific batch processes in
operation. However, commodities such as dyes and dye
intermediates, fatty acids, primary derivatives of fatty
acids, plasticizers, and pigments were considered as
subgroups of materials whose manufacturing operations can be
considered as a segment of the industry for which effluent
limitations and standards can be applied.
The RWL values assigned to each of the 55 secondary organic
product-product groupings were then placed in the major
process subcategories described in Section IV (Industry
Categorization). Consideration of differences in the
feedstocks, unit operations, and chemical conversions is
349
-------
implicit in this method of subcategorization as discussed in
Section IV.
Tables 5-1 through 5-U, show the raw waste loads for each of
the 55 product/process segments investigated in this study.
Only 29 product/process segments were selected for the
application of effluent limitations and guidelines. The raw
waste loads and applicable reduction factors / or
concentrations are presented in Table 9-1 for the 29
product/processes.
Although the effluent limitations guidelines for BPCTCA may
be obtained by whatever combination of in-process and end-
of-process means is best suited to the individual
manufacturers, the numerical values for the guidelines were
calculated through the application of waste reduction
factors based upon the use of a biological treatment system.
The waste reduction factors used for calculating the BPCTCA
effluent limitations guidelines for the BOD and COD
parameters are listed as follows:
BOD range 83-99 percent reduction
(93 percent average)
COD 74 percent reduction
These factors are based upon the performance of biological
treatment systems described in Section VII - Control and
Treatment Technologies. The performance data used to
develop these factors, in many cases, were obtained over a
full year's operation and are indicative of treatment
systems which accept a wide variety of wastes. For this
reason, these same reduction factors were applied to the
BPCTCA mean RWL for each subcategory in the following
manner:
(1) The reduction factor of 93 percent was applied to
the subcategory mean raw waste load whenever the
effluent concentration for the subcategory mean
flow, gallons per 1000 Ib product is between 20 and
30 mg/1.
(2) Whenever the resultant concentration is below 20
mg/1 after applying the 93 percent reduction
factor, a less stringent effluent reduction was
determined based on the concentration limiting
basis of 20 mg/1.
(3) Whenever the resultant effluent concentration is
above 30 mg/1 with 93 percent reduction a higher
350
-------
reduction is required based on 30 mg/1 effluent up
to a maximum reduction of 99 percent.
It is noted that BOD should be used as the controlling
parameter for BPCTCA effluent limitation guidelines. The
values specified for COD should only be used where it can be
demonstrated through the use of biological treatability
studies that the waste (even after dilution with other
wastes from the plant) can not be effectively reduced in a
biological system. In such cases it is anticipated that
some combination of in-process controls, coupled with end-
of-process systems such as activated carbon adsorption
applied to any of the 29 product-product groupings, can
provide the required 74 percent reduction of COD. In
addition, the 74 percent represents an overall efficiency
and therefore can be related to the end-of-process treatment
facilities in which some product/process having greater or
less than this volume will be treated. It should also be
noted that compliance with both the BOD and COD effluent
limitations is not required. Reduction of the BOD to levels
developed through the application of the 93 percent
reductions is considered generally for BPCTCA end-of-process
reduction of the principal pollutant, BOD5. Due to the
extremely high waste load observed in some of the
subcategory groups, and the need for in-process controls to
assure that these wastes are treatable, reduction factors
higher than 93 percent were recommended for specific cases.
The remaining two general pollutant parameters for which
BPCTCA effluent limitations guidelines are specified are
total suspended solids (TSS) and pH. The basis for these
limitations guidelines are as follows:
TSS 60 mg/1 (30 day maximum average)
135 mg/1 (maximum daily limitation)
pH 6-9
The long term TSS concentration from which the above
limitations were derived is 30 mg/1. Variability factors of
2.1 and 3.9 were then applied to the long term concentration
of 30 mg/1 in order to obtain the 30 day maximum average and
the daily maximum limitations.
BPCTCA effluent values for the BOD and COD parameters were
obtained in the manner indicated previously. These values
shown as the BPCTCA effluent should not be directly applied
as effluent limitations guidelines. They must be first
multiplied by adjustment factors based on treatment plant
performance developed in Section XIII. The last two columns
351
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in Table 9-1 indicate the actual effluent limitations
guidelines for BPCTCA which have been adjusted for:
1. The maximum average of daily values for any period
of 30 consecutive days = 2.1 x long term average.
2. The maximum value for any one day = 3.9 x long term
average.
The total effluent limitation for a multi-process plant
would be the summation of these values relating to
individual processes. Limitations for TSS and pH relate to
the entire facility and should be applied in the manner
shown in Table 9-1.
Finally, effluent limitations for specific pollutant
parameters which are applicable to specific product/process
segments were determined to be applicable to BPCTCA.
Cyanide limitations are also established for HMDA,
acryionitrile and adiponitrile product/processes based upon
the achievement of effluent concentrations below 0.5 mg/1
and 1.0 mg/1 for the average of 30 consecutive days and the
daily maximum respectively. Heavy metals limitations for
the plasticizers segment (Cu) were based upon the
achievability of less than 1 mg/1 concentration (daily
maximum basis and 0.5 mg/1/30 day maximum average).
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TABLE 9-1
DEVELOPMENT OF BPCTCA EFFLUENT LIMITATIONS
SIGNIFICANT ORGANIC PRODUCTS SEGMENT OF THE ORGANIC CHEMICALS
MANUFACTURING POINT SOURCE CATEGORY
SUBCATEGORY
FLOW
L/kkg
Nonaqueous Process - Subcategory A
BTX Aromatics 46.7
Cumene
p-xylene 44.3
RAW WASTE LOAD
gal/1000 Ib
6.6
Negligible
5.3
Process With Process Water Contact Only as Steam Diluent,
Chloromethanes 2800
Diphenylamine 526
Phthalic Anhydride 593
(oxidation of o-xylene)
Hexamethylenediamine(2) 1,010
(adiponitrile process)
Hexamethylenediamirie(2) 1,100
(hexanediol process)
Methyl ethyl ketone 1,310
Adiponitrile(2) 9,770
Benzoic Acid &Benzaldehyde 2,840
Maleic Anhydride 2,300
335
63
71
121
132
157
1,170
340
274
BOOS COD
lb/1000 Ib or kg/kkg(mg/l)
0.015(32 ) 0.053(113 )
Negligible
0.01 (238) 0.025(580)
Quench or Vent Gas Absorbent -
0.22 (77) 0.94 (335)
0.087(164) 0.31 (600)
0.13(215) 0.64(1,080)
3.97(3,930) 21(20,900)
4.0(3.630) 11.7(10,600)
3.9(3,000) 2.1(1,630)
19.2(1,970) 135(13,800)
25.6(9,010) 51(17,900)
108(47,000) 287(126,000)
BASIS for BPCTCA
LIMITS
93% (23 mg/1)
N/A
20 mg/1 (91*)
Subcategory B
20 mg/1 (74*)
20 mg/1 (88*)
20 mg/1 (91*)
99% (39 mg/1)
99% (36 mg/1 )
30 mg/1 (99*)
30 mg/1 (98.5%)
99% (90 mg/1 )
99% (470 mg/1 )
Aqueous Liquid Phase Reaction Systems - Subcategory C
Ethyl Acetate 1,290
Isopropanol 2,540
Calcium Stearate 54,100
Hydrazine 30,300
Isobutylene 20,400
Sec Butyl Alcohol 626
Acrylonitrile(2) 4,470
p aminophenol 12,600
Batch and Semi -Continuous Process -
o-nitroaniline 269,000
p-nitroaniline 39,100
lonone and Methyl ionone 9,370
Methyl Sallcylate 1,735
Citronellol and Geraniol 10,000
Plasticizers (3) 650
Tannic Acid 10,000
155
304
6,460
3,630
2,440
75
536
1,510
Subcategory D
32,200
4,680
1,120
208
1,199
78
1,200
0.049(38) 0.1(79)
0.99 (393) 2.99 (1,127)
13.8(255) 32.8(605)
9.09 (300) 115 (3800)
13.6(670) 64.1(3,150)
14.2(22,800) 38.8(62,000)
38.7(8,620) 133 (32,800)
41.6(3,300) 73.7(5,850)
16 (61) 105(390)
2.55(65) 79.1(2,030)
24 (2,60(1) 94 (10,000)
22 (12.680) 93.9(54,100)
58 (5,810) HI (11,000)
54 (82,600) 83 (127,000)
153 (15,300) 1,070(107,000)
20 mg/1 (47*)
93% (27 mg/1)
20 mg/1 (92*)
21 mg/1 (93*)
30 mg/1 (96*)
99% (228 mg/1 )
99% (87 mg/1)
99% (33 mg/1 )
20 mg/1 (67*
20 mg/1 (69*
30 m /I (99%
99% 126 mg/1)
99% 58 mg/1)
99* 826 mg/i )
99% 153 mg/lj
BODS
LIHITQ )
0.0010
Negligible
0.00090
0.056
0.010
0.012
0.040
0.040
0.039
0.29
0.26
1.1
0.026
0.069
1.1
0.64
0.61
0.14
0.39
0.42
5.4
0.78
0.28
0.22
0.58
0.54
1.5
TSS
LIRIIMl
(a 30 mg/1
0.0014
Negligible
0.0013
0.084
0.016
0.018
0.030
0.033
0.039
0.29
0.085
0.069
0.039
0.076
1.6
0.91
0.61
0.019
0.13
0.38
8.1
1.2
0.28
0.052
0.30
0.020
0.30
(1) Variability factors applicable for the daily maximum and 30 day maximum average are 3.9 x and 2.1 x ( mean limit) respectively
ill L]mltajlons/or- cyanide established on the basis of 1.0 mg/1 and 0.5 mg/1 for the daily maximum and 30 day maximum average limitation.
(.i) Limitation for total copper established on the basis of 1.0 mg/1 and 0.5 mg/1 for the daily maximum and 30 day maximum average limitation.
-------
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SECTION X
BEST AVAILABLE TECHNOLOGY ECONOMICALLY
ACHIEVABLE (BATEA)
Best available technology economically achievable (BATEA)
for the Secondary Products segment of the organic chemicals
point source category is based upon the most exemplary
combination of in-process and end-of-process treatment and
control technologies.
In-process practices include those mentioned previously for
BPCTCA as well as the following:
1. The reuse of aqueous waste streams from one process
in another so that the discharge is eliminated.
2. The recycle of waste streams from one unit
operation within a process to another with the
subsequent recovery of a product or co-product.
3. The concentration and disposal of waste waters by
means which eliminate the discharge entirely.
Process modifications for BATEA go beyond those described
for BPCTCA in that they would require changes to major unit
operations or chemical conversions within the process. For
example, recycle of aqueous waste streams for product
recovery might involve replacement of existing distillation
columns or reactors.
Other examples of practices consistent with BATEA include:
the reuse of aqueous hydrochloric acid streams in the
manufacture of different chlorinated methanes; the recycle
of aqueous waste streams for product recovery in the
manufacture of hexamethylene diamine, maleic anhydride, and
methyl ethyl Jcetone; and the use of evaporators or
incinerators to completely eliminate discharges in the
manufacture of phthalic anhydride and p-aminophenol.
The wide diversity of the organic chemicals industry pre-
vents prescribing a concise list of process modifications
which are applicable to the industry as a whole (or even to
the small fraction of its products covered in both phases of
this study). This problem is aggravated by the fact that
tne industry as a whole zealously guards information
relating to the nature of specific manufacturing processes.
This secrecy may or may not be warranted in order to
maintain a competitive positions. However, it is difficult
to develop effluent limitations guidelines based solely upon
355
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the application of in-process technologies. Therefore,
although the use of in-process techniques may represent a
viable alternative for specific manufacturers, general
effluent limitations guidelines for BATEA have been
developed based upon the application of additional end-of-
process treatment technologies.
Treatment commensurate with BATEA requires the application
of activated carbon adsorption or the use of additional
biological systems in series with the treatment previously
described for BPCTCA. The specific choice of which system
should be utilized depends upon the specific process or
group of processes in operation at any given facility.
Tne performance of these treatment systems has been
discussed in Section VII - Control and Treatment
Technologies. The incremental waste reductions associated
with these technologies is indicated as follows for the BOD
and COD parameters:
BOD 89 percent reduction (BATEA effluent is 11 percent
of BPCTCA effluent).
COD 69 percent reduction (BATEA effluent is 31 percent
of BPCTCA effluent) .
Effluent limitations guidelines for BATEA were calculated by
applying these reduction factors to average effluent for
BPCTCA shown in Table 9-1.
There are specific subcategories where the direct use of
these reduction factors will still result in effluent
concentrations which are below the capabilities of the
control systems considered as BATEA. In this case, effluent
limitations for BATEA were obtained by applying minimum
concentration of 10 mg/1 BOD5_ and 50 mg/1 COD from the mean
waste water flow from each subcategory group.
Cyanide limits for HMDA, adiponitrile and acrylonitrile
products are based on achievable concentration of 0.5 mg/1
and 0.25 mg/1 for the daily maximum and 30 day maximum
average limitations respectively. Copper (Cu) limitations
for plasticizers are also based on achievable concentrations
of 0.5 mg/1 and 0.25 mg/1 respectively.
It, is also noted that the BATEA requires suspended solids
removal to an average concentration of 15 mg/1 through the
use o± filtration or other treatment technique which is
equally effective.
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The effluent limitation guidelines for BATEA are presented
in Table 10-1. The BOD, COD and TSS values specified as the
average effluent for BATEA. should not be directly applied
before adjustment for variations in treatment plant
performance. The factors used here are the same as for
BPCTCA and are discussed in Section XIII - Variation in
Treatment Plant Performance.
357
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TABLE 10-1
DEVELOPMENT OF BATEA EFFLUENT LIMITATION FOR THE
SIGNIFICANT ORGANIC PRODUCTS SEGMENT OF THE ORGANIC CHEMICALS
MANUFACTURING POINT SOURCE CATEGORY
BPCTCA
EFFLUENT LIMITATION
FLOW
BODS
COD
L/kkg lb/1000 Ib or kg/kkg (mg/1)
Nonaqueous Process - Subcategory A
BTX Aromatlcs 46.7
Cumene No Discharge
p-xylene 44.3
Process With Process Water Contact Only
Chloromethanes 2800
D1phenylam1ne 526
Phthalic Anhydride 593
(oxidation of o-xylene)
Hexamethylenediamine 1,010
(adiponitHle process)(3)
Hexamethylenediamine 1,100
(hexanediol process) (3)
Methyl ethyl ketone 1,310
Adiponitrile(3) 9,770
Benzole Acid & Benzaldehyde 2,840
Maleic Anhydride 2,300
0.0010(23)
No Discharge
0.00090(20)
as Steam Diluent
0.056(20)
0.010(20)
0.012(20)
0.040(39)
0.040(36)
0.039(30)
0.29(30)
0.26(90)
1.1(470)
0.04
No Discharge
0.0065
BODS BATEA (1 )
EFFLUENT LIMITATION
BASIS LIMITATION
mg/1 or % lb/1000 Ib or kg/kkg(mg/l)
10 mg/1 (57%)
No Discharge
10 mg/1 (50%)
0.00047
0.00045
COD BATEA (2) TSS (1)
EFFLUENT LIMITATION LIMIT ? 15 mg/1
BASIS
LIMITATION lb/1000 Ib or
mg/1 or % lb/1000 Ib or kg/kkg
69%
No
69%
kg/kkg
0.0042
discharge
0.0022
0.00070
No Discharge
0.00066
, Quench or Vent Gas Absorbent - Subcategory B
0.24
0.081
0.17
5.5
3.0
0.55
35
13
75
10 mg/1 (50%)
10 mg/1 (50%)
10 mg/1 (50%)
10 mg/1 (74%)
10 mg/1 (72%)
10 mg/1 (67%)
10 mg/1 (67%)
10 mg/1 (89%)
89% (50 mg/1 )
0.028
0.053
0.0060
0.010
0.011
0.013
0.10
0.028
0.12
50 mg/1
50 mg/1
69%
69%
69%
69%
69%
69%
69%
0.14
0.26
0.050
1.7
0.94
0.17
11
4.1
23
0.042
0.0080
0.0090
0.015
0.016
0.020
0.14
0.042
0.035
Aqueous Liquid Phase Reaction Systems - Subcategory C
Ethyl Acetate
Isopropanol
Calcium Stearate
Hydrazine
Isobutylene
Sec Butyl Alcohol
Acrylonitr1le(3)
p aminophenol
1,290
2,540
54,100
30,300
20,400
626
4,470
12,600
0.026 (20)
0.069(27)
1.1(20)
0.64 (21)
0.61(30)
0.14(228)
0.39(87)
0.42(33)
0.065
0.78
8.5
30
17
10
35
19
10 mg/1 (50%)
10 mg/1 (63%
10 mg/1 (50%
10 mg/1 (50%
10 mg/1 (67%
89% (25 mg/1
10 mg/1 (89%)
10 mg/1 (70%]
0.013
0.025
0.54
0.3
0.20
0.016
0.045
0.13
50 mg/1
69%
50 mg/1
69%
69%
69%
69%
69%
0.065
0.24
2.7
9.2
5.1
3.1
11
5.9
0.020
0.038
0.81
0.45
0.30
0.0095
0.067
0.19
Batch and Semi-Continuous Process - Subcategory D
4(20)
o-nitroaniline
p-nitroaniline
lonone and Methylionone
Methyl Sal icylate
Citronellol and Geraniol
Plasticizers (4)
Tannic Acid
269,000
39,100
9,370
1,735
10,000
650
10,000
0.78(20)
0.28(30)
0.22(126)
0.58(58)
0.54(826)
1.5(t53)
27
20
25
24
29
22
278
50%)
50%)
67%)
10 mg/1
10 mg/1
10 mg/1 „,»,
89% (14 mg/1)
10 mg/1 (83%)
89% (91 mg/1)
89% (17 mg/1)
2.7
0.39
0.094
0.024
0.10
0.059
0.17
50 mg/1
69%
69%
69%
69%
69%
69%
13
6.3
7.8
7.5
8.9
6.6
86
4.0
0.59
0.14
0.026
0.15
0.0095
0.15
(4
Effluent limits for daily maximum and 30 day maximum average are based on variability factors 3.9 x and 2.1 x (mean limit).
COD values are not limitations on BPCTCA but are utilized as 74% reduction basis for BATEA limitations.
Limitation for cyanide established on the basis of 0.5 mg/1 and 0.25 mg/1 for the daily maximum and 30 day maximum average.
Limitation for copper established on the basis of 0.5 mg/1 and 0.25 mg/1 for the daily maximum and 30 day maximum average.
-------
SECTION XI
NEW SOURCE PERFORMANCE STANDARDS
Determination of the best available demonstrated control
technology (BADCT) for new sources of the 29 product/process
segments involves the evaluation of the most exemplary in-
process control measures with exemplary end-of-process
treatment. Some major in-process controls which were fully
described in Section VII are applicable to new sources as
follows:
(1) The substitution of noncontact heat exchanger using
air, water or refrigerants for direct contact water
cooling equipment (barometric condensers);
(2) The use of nonaqueous quench media, e.g., such as
furnace oil, as a substitute for water, where
direct contact quench is required;
(3) The recycle of process water, such as between
absorber and stripper;
(4) The reuse of process water (after treatment) as
make-up to evaporative cooling towers through which
noncontact cooling water is circulated;
(5) The reuse of process water to produce low pressure
steam by noncontact heat exchangers in reflex
condensers or distillation columns;
(6) Recycle cooling for contact water systems
(barometric condensers);
(7) The recovery of spent acid or caustic solutions for
reuse;
(8) The recovery and reuse of spent catalyst solutions;
(9) The use of nonaqueous solvents for extraction of
products with subsequent recovery of solvent; and
(10) Addition of demisters.
Although these control measures are generally applicable, no
attempt was made to identify all of these or any single one
as universally applicable. There are other equally
appropriate control measures which should be carefully
explored and utilized by new plants in this industry.
359
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The end-of-process treatment model has been determined to be
biological treatment with the additional suspended solids
removal by clarification, sedimentation, sand and/or dual
media filtration.
Although biological treatment has been described as the
basis for the BADCT, it is recognized that chemical-physical
systems such as activated carbon may also be employed as an
end-of-process technology or as an in-process or by-product
recovery system. It may also be necessary to remove certain
wastes which are toxic to or interfere with biological waste
treatment systems by in-process chemical-physical control
processes.
The BODJ5 reductions that were used to develop the BADCT
limitations are discussed in Section VII, Control and
Treatment Technology. These reductions were applied to the
effluent obtained from BPCTCA and are listed as follows:
BOD5 17* reduction (BADCT effluent is 83X of BPCTCA
effluent) .
COD 20% reduction (BADCT effluent is 80* of BPCTCA
effluent) .
As with BPCTCA, the major oxygen demand pollutant parameter
is BOD5 for which effluent limitations guidelines are
established. TSS limitations are based upon an achievable
concentration of 15 mg/liter. Cyanide limitations for HMDA,
acrylonitrile and adiponitrile products, as well as copper
limits for plasticizers, were based upon the same
technologies and achievable limits as BPCTCA (Section IX).
The variability associated with the BADCT model treatment
process was assumed to be nearly the same as that for BPCTCA
since both systems are identical except for filtration which
is added to the biological system for BADCT.
Standards of performance for new sources are presented in
Table 11-1.
360
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TABLE 11-1
DEVELOPMENT OF STANDARDS OF PERFORMANCE FOR THE
SIGNIFICANT ORGANIC PRODUCTS SEGMENT OF THE ORGANIC CHEMICALS
MANUFACTURING POINT SOURCE CATEGORY
SUBCATEGORY
FLOW
RPC.Tr.A EFFLUFNT
BODS
L/kkglb/1000 Ib or kg/kkg (mg/1)
BODS LIMITATION
kg/kkq or lb/1000 Ib
NSPS EFFLUENT fl]
TSS LIMITATION
kg/kkg or Ib/lOOO
(at 15
Nonaqueous Process - Subcategory A
BTX Aromatics 46.7 0.0010(23)
Cumene No Discharge No Discharge
p-xylene 44.3 0.00090(20)
0.00083
No Discharge
0.00075
Process With Process Water Contact Only as Steam Diluent, Quench or Vent Gas Absorbent - Subcategory B
0.00070
No Discharge
0.00066
Chloromethanes 2,800
Diphenylamlne 526
Phthalic Anhydride 593
(oxidation of p-xylene)
Hexamethylenediamine 1,010
(adiponitrile process)(2)
Hexamethylenediamine 1,100
(hexanediol process)(2)
Methyl ethyl ketone 1,310
Ad1pon1trile (2) 9,770
Benzole Acid and Benzaldehyde 2,840
Maleic Anhydride 2,300
Aqueous Liquid Phase Reaction Systems - Subcategory C
Ethyl Acetate
Isopropanol
Calcium Stearate
Hydrazine
Isobutylene
Sec Butyl Alcohol
Acrylonitrile(2)
p-aminophenol
1,290
2,540
54,100
30,300
20,400
626
4,470
12,600
0.056(20)
0.010(20)
0.012 (20)
0.040(39)
0.040(36)
0.039(30)
0.29(30)
0.26(90)
1.1(470)
0.026(20)
0.069(27)
0.64 (21)
0.61(30)
0.14
0.39
0.42
228)
87)
33)
0.046
0.0083
0.010
0.033
0.033
0.032
0.24
0.22
0.91
0.022
0.057
0.91
0.53
0.51
0.12
0.32
0.35
0.042
0.0080
0.0090
0.015
0.016
0.020
0.14
0.042
0.035
0.020
0.038
0.81
0.45
0.30
0.0095
0.067
0.19
Batch and Semi-Continuous Process - Subcategory D
o-nitroaniline 269,000
p-nitroaniHne 39,100
lonone and Methylionone 9,370
Methyl Salicylate 1,735
Citronellol and Geraniol 10,000
Plasticizers (3) 650
Tannic Acid 10,000
5.4(20)
0.78
0.28
0.22
0.58
0.54
1.5(1
20)
30)
126)
58)
826)
53)
4.5
0.65
0.23
0.18
0.48
0.45
1.2
4.0
0.59
0.14
0.026
0.15
0.0095
0.15
(1) Effluent limitation for the daily maximum and 30 day maximum average are based on variability factors
3.9 x and 2.1x (mean limit).
(2)
(3)
Limitation for cyanide established on the basis of 1.0 mg/1 and 0.5 mg/1 for the daily maximum and 30 day maximum average.
Limitation for copper established on the basis of 1.0 mg/1 and 0.5 r-g/1 for the daily maximum arid 30 day maximum average.
361
-------
-------
SECTION XII
P&ETREATMENT GUIDELINES
Pollutants from specific processes within the organic
chemicals industry may interfere with, pass through
inadequately treated, or otherwise be incompatible with a
publicly owned treatment works. The following section
examines the general waste water characteristics of the
industry and tne pretreatment unit operations which may be
applicable.
A review of the waste water characteristics indicated that
certain products can be grouped together on the basis of
pollutants requiring pretreatment. Accordingly, the
previously determined subcategories were divided into two
Sub-Groups as follows:
Subgroup 1 Subgroup 2
Subcategory A Subcategory C
Subcategory B Subcategory D
The principal difference in the general characteristics of
the process waste waters from the manufacture of chemicals
in these two Subgroups is that the waste waters of Subgroup
1 are more likely to include significant amounts of free and
emulsified oils (petroleum origin), whereas the waste waters
of Subgroup 2 are more likely to include significant amounts
of heavy metals. Detailed analyses for specific products in
the industry are presented in Section IV.
The types and amounts of heavy metals in the waste water
depend primarily on the manufacturing process and on the
amounts and types of catalysts lost from the process. Most
catalysts are expensive, and therefore are recovered for
reuse. Only recoverable catalysts (heavy metals), generally
in small concentrations, appear in the waste water. The
products and processes in Subgroup 2 are most likely to have
heavy metals in their waste water, and waste waters
associated with dye/pigment production (Subcategory D) also
may have high heavy metal concentrations due to the
production of metallic dyes. Fatty acid waste waters
(Subcategory D) contain free and emulsified oil (animal and
vegetable origin) of significance.
The manufacture of acrylonitrile (Subcategory C) produces a
highly toxic waste water which is difficult to treat
Biologically unless adequate provisions are made for
363
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pretreatment of these waste waters for removal of the
cyanide pollutant. The toxicity characteristics have been
attributed to the presence of hydrogen cyanide in excessive
quantities (200 mg/1). In addition, the waste water is
generally acidic (pH 4 to 6) and contains high
concentrations of organic carbon (TOC = 18,500 mg/1). These
waste waters are generally segregated from other process
wastes and are disposed of by other means (e.g.
incineration); they are not generally discharged to
municipal collection systems. For these reasons, the
pretreatment unit operations developed in the following
section do not include the process waste waters from the
manufacture of acrylonitrile.
Tafcle 12-1 shows the pretreatment unit operations which may
be necessary to protect joint waste water treatment
processes.
Oil separation may be required when the oil (petroleum
origin) content of the waste water exceeds 100 mg/1. Animal
and vegetable oils in the fatty acid waste waters should be
segregated in order to minimize solids separation problems
in the waste water treatment facility.
The heavy metals present in organic chemical wastes are in
many cases so low in concentration that heavy metals removal
is not required from the standpoint of treatability
characteristics. However, the effluent limitations for
toxic pollutants may require additional pretreatment
(chemical precipitation) for removal of these materials.
The pretreatment unit operations generally consist of
equalization, neutralization, and oil separation. In
addition, phenol recovery (to reduce the phenol
concentrations) and spill protection for spent acids and
spent caustics may be required in some cases.
Biological Treatment Inhibition
The scope of this study did not allow for a specific
toxicity evaluation of individual product waste waters.
However, the completeness of the RWL analytical data did
provide a waste water profile which could be used to
evaluate possible biological inhibition. The list and
concentrations of inhibitory pollutants in EPA's Federal
Guidelines - Pretreatment of Discharge to Publicly Owned
Treatment Works were examined, and specific comments are
presented in Section VI. This previous list was amended in
the Phase I report to include phenol and iron:
Inhibition to Inhibition to
Parameter Biological Treatment Anaerobic Sludge Digestion
Phenol 50 mg/1
Iron 5 mg/1
364
-------
Table 12-1
Pretreatment Unit Operations For the
Organic Chemicals Industry
Pretreatment
Sub-Group
1
OJ
cr\
Suspended Growth
Biological System
Oi 1 Separat i on +
Equa1i zation +
Neutralization +
Spi11 Protection +
Chemical Precipita-
tion '
Fixed Growth
Biological System
Oi 1 Separati on +
Equali zation +
Neutra1i zation +
Spi11 Protect!on +
Chemical Precipita-
tion'
Independent Physical -
Chemical System
Oi1 Separation +
Equa1i zatton +
Neutra1i zat ion +
Chemical Precipitation
1
Equa1i zation +
Neutra1i zati on +
Spi11 Protection +
Chemical Precipita-
tion'
Equa1i zation +
Neutra1i zati on
Equa1i zation +
Neutra1i zation
1
Need for chemical precipitation depends on extent of catalyst recovery.
"Oil separation may be required for the fatty acid industry.
-------
-------
SECTION XIII
ALLOWANCE FOR VARIABILITY IN TREATMENT PLANT PERFORMANCE
Variabilty in Biological Waste Treatment Systems
In the past, effluent requirements for wastewater treatment
plants have been related to the achievement of a desired
treatment efficiency based on long term performance. There
are, however, factors that affect the performance and hence
the effluent quality or treatment efficiency over the short
term, such that short term performance requirements cannot
be taken directly from the longer term data. Knowledge of
these factors must be incorporated in the development of
effluent limitations and in decisions of whether a treatment
plant is in compliance with the limitations.
The effluent limitations promulgated by EPA and developed in
this Document include values that limit both long term and
short term waste discharges. These restrictions are
necessary to assure that deterioration of the nation1s
waters does not occur on a short term basis due to heavy
intermittent discharges, even though an annual average may
be attained.
Most of the factors that bring about variations in treatment
plant performance can be minimized through proper dosing and
operation. Some of the controllable causes of variability
and techniques that can be used to minimize their effect
include:
A. Storm Runoff
Storm water holding or diversion facilities should be
designed on the basis of rainfall history and area being
drained. The collected storm runoff can be drawn off at
a constant rate to the treatment system. The volume of
this contaminated storm runoff should be minimized
through segregation and the prevention of contamination.
Storm runoff from outside the plant area, as well as
uncontaminated runoff, should be diverted around the
plant or contaminated area.
B. Flow Variations
Products-process upsets and raw waste variations can be
reduced by properly sized equalization units.
Equalization is a retention of the wastes in a suitably
designed and operated holding system to average out the
influent before allowing it into the treatment system.
367
-------
C. Spills
Spills of certain materials in the plant can cause a
heavy loading on the treatment system for a short period
of time. A spill may not only cause higher effluent
levels as it goes through the system, but may inhibit a
biological treatment system and therefore have longer
term effects. Equalization helps to lessen the effects
of spills. However, long term reliable control can only
be attained by an aggressive spill prevention and
maintenance program including training of operating
personnel. Industrial associations such as the
Manufacturing Chemists Association have developed
guidelines for prevention, control and reporting of
spills. These note how to assess the potential of spill
occurrence and how to prevent spills. Each industrial
organic chemical plant should be aware of the MCA report
and institute a program of spill prevention using the
principles described in the report. If every plant were
to use such guidelines as part of plant waste management
control programs, its raw waste load and effluent
variations would be decreased.
D. Start-up and Shut-down
These periods should be reduced to a minimum and their
effect dampened through the use of equalization
facilities and by proper scheduling of manufacturing
cycles.
E. Climatic Effects
The design and choice of type of a treatment system
should be based on the climate at the plant location so
that this effect can be minimized. Where there are
severe seasonal climatic conditions, the treatment
system should be designed and sufficient operational
flexibility should be available so that the system can
function effectively.
F. Treatment Process Inhibition
Chemicals likely to inhibit the treatment processes
should be identified and prudent measures taken to see
that they do not enter the wastewater in concentrations
that may result in treatment process inhibition. Such
measures include the diking of a chemical use area to
contain spills and contaminated wash water, using dry
instead of wet clean-up of equipment, and changing to
non-inhibiting chemicals.
368
-------
The common indicator of the pollution characteristics of the
discharge from a plant historically has been the long-term
average of the effluent load. However, the long-term
(yearly) average is not the only parameter on which to base
an effluent limitation. Shorter term averages also are
needed, both as an indication of performance and for
enforcement purposes.
Wherever possible, the best approach to develop the annual
and shorter term limitations is to use historical data from
the industry or product-process line in question. If enough
data is available, the shorter term limitations can be
developed from a detailed analysis of the hourly, daily,
weekly, or monthly data. Rarely, however, is there an
adequate amount of short term data. However, using data
which show the variability in the effluent load, statistical
analyses can be used to compute short term limits (30 day
average or daily) which should be attained, provided that
the plant is designed and run in the proper way to achieve
the desired long term average load. These analyses can be
used to establish variability factors for effluent
limitations or to check those factors that have been
developed.
During the industry survey, EPA tried to use all historical
performance data that were available. Unfortunately, data
were available only for four plants, Amoco, Joliet,
Illinois; Amoco, Decatur, Alabama; DuPont, Belle, West
Virginia; and Union Carbide at Institute, West Virginia.
The Agency used long term performance information from these
facilities to establish the variability factors for the
Phase I regulations. The counsel for industry petitioners
in challenges to the Phase I regulations vigorously objected
to the use of these data points, or said that if these data
were to be used, much higher variability factors should be
derived.
For the Significant Organic Products Segment of the Organic
Chemicals Manufacturing Point Source Category EPA has used a
data base consisting of 21 organic chemicals, plastics and
petrochemical plant performance data, to establish daily
maximum and monthly average variability factors. While
these plants make different products. Agency analysis
revealed that they can be grouped because the treatment
plant characteristics and response to flow and constituent
variables, for example, are similar. Plants examined
include the Amoco, Decatur, Alabama, Yorktown, Va. and
Joliet, Illinois plants; B.F. Goodrich, Fredricktown, N.J.
facility; B.W. Marlion, Ottawa, Illinois; Borden Chemical,
Illiopolis, Illinois; Celanese Fiber, Rock Hill, S.C.;
369
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F.M.C. Corporation, Fredricksburg, Va.; Fiber Industries,
Salisbury, N.C.; Champlin, Corpus Christi, Texas; Marathon, /
Texas City, Texas; Shell, Houston, Texas and Martinez,
California; and several oil refineries about which data were
supplied by the American Petroleum Institute.
The BODS variability from these plants has been calculated
in the following way: it is known from the properties of
normal distribution that 99 percent of all effluent
observations will have a value less than ;u + 2.3270 and that
C29/C5J) = 1Q2.327 x cr . The relationship between the
average value, median value and standard deviation of the
logarithm of a log normally distributed variable can be
expressed: A = joP+(2.303 a2) * 2 and C50 = Kr" , therefore,
CSjO/A = !Q-(2.303 a2) * 2 • Using these bases, the daily
maximum variability factor (C9_9_/A) equals 2.10. These are
the factors that have been used to generate effluent
regulations for the product-processes covered by this
Document.
The data base upon which EPAfs variability factors are based
is the most extensive available. Commenters on these and
prior EPA Development Documents have suggested no other
source of information on which to base BODS, TSS or COD
variability factor calculation. While it is known that the
behavior of waste characteristics such as COD and TSS are
not precisely the same as BODS in variations of effluent,
and that use of different treatment techniques can alter
expected variations, there are not data sources for COD
which can be used to generate separate variability numbers.
While there is slight information available on TSS
variability, it is not enough upon which to rely solely, and
appears to be consistent with the BODS variability factors.
If anyone has more or better information available, the
Agency will readily consider it. For these reasons, EPA has
used factors of 2.1 and 3.9 for all pollutant parameters,
for regulations covering existing plants and new sources.
370
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SECTION XIV
ACKNOWLEDGMENTS
This report was prepared for the Environmental Protection
Agency by the staff of Roy F. Weston Co. under the direction
of Mr. James Dougherty, Project Director. The following
individuals of the staff of Roy F. Weston Co. made
significant, contributions to this effort:
Mr. David Smallwood, Project Manager
Mr. Charles Mangan, Project Engineer
Mr. Kent Patterson, Project Engineer
Mr. James Weaver, Project Engineer
Dr. Sun-nan Hong, Project Engineer
Mr. John A. Nardella, Project Officer, Effluent Guidelines
Division, contributed to the overall supervision of this
study and preparation of the draft report.
Mr. Allen Cywin, Director, Effluent Guidelines Division, and
Mr. Walter J. Hunt, Chief, Effluent Guidelines Development
Branch, offered guidance and helpful suggestions. Members
of the Working Group/Steering Committee who coordinated the
internal EPA review are acknowledged:
Mr. Walter J. Hunt, Effluent Guidelines Division, Chairman
Mr. John A. Nardella, Effluent Guidelines Division,
Project officer
Mr. George Rey, Office of Research and Development
Dr. Thomas Short, Ada Laboratory, Office of Research
and Development
Mr. Davxd G. Davis, Office of Planning and Evaluation
Mr. James Rogers, Office of General Counsel
Mr. Wayne Smith, NFIC, Denver
Mr. John Lank, Region IV, Atlanta
Mr. Joseph Davis, Region III, Philadelphia
Mr. Ray George, Region III, Philadelphia
Mr. Albert Hayes, Office of Solid Waste Management
Mr. Frank Kover, Office of Toxic Substances
Special appreciation is given to Dr. Raymond Loehr, Effluent
Guidelines Division Program Advisor, Dr. Robert Swank, EPA
Athens, Georgia Laboratory, and Dr. W. Lamar Miller,
Effluent Guidelines Division, for reviewing this document
and suggesting technical and editorial improvements.
Acknowledgement and appreciation is also given to the
secretarial staffs of both Effluent Guidelines Division and
Roy F. Weston Co. for their efforts in the typing of drafts,
371
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necessary revisions, and final preparation of the effluent
guidelines document. Appreciation is especially given to
the following:
Ms. Kay Starr, Effluent Guidelines Division
Ms. Brenda Holmone, Effluent Guidelines Division
Ms. Nancy Zrubek, Effluent Guidelines Division
Appreciation is also extended to both the Manufacturing
Chemists' Association and the Synthetic Organic Chemical
Manufacturers' Association for the valuable assistance and
cooperation given to this program. Appreciation is also
extended to those companies which participated in this
study:
Accent International, Inc.
Allied Chemical Corporation
American Cyanamid Company
Armak Chemcial Company
BASF - Wyandotte Company
Benzeroid Organics, Inc.
Borg Warner Chemicals, Inc.
Ceianese Chemical Company
Conoco Chemicals, Inc.
E.I. DuPont de Nemours, Inc.
Emery Industries, Inc.
Exxon Chemical Company, U.S.A.
General Mills, Inc.
Givaudan Corporation
Glyco Chemicals, Inc.
A. Gross & Company
Hercules, Inc.
Hooker Chemical Corporation
Jefferson Chemical Company
Kraftco Corporation
Mallinckrodt Chemical company
Monsanto, Inc
Olin Corporation
Petro - Tex Chemical Corporation
Pfizer, Inc.
Pit - Consol Chemical Company
Roma Chemicals, Inc.
Rubicon Chemicals, Inc.
shell Chemical Corporation
Sherwin - Williams Corporation
Stepan Chemical Company
Sun Oil Company
Tenneco Chemicals, Inc.
Union Carbide Corporation
Vulcan Materials Company
USS Chemicals, Inc.
Vistron Corporation
372
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SECTION XV
BIBLIOGRAPHY
This bibliography supplements the main bibliography
previously presented in the Phase I study.
Development Document for Proposed Effluent Limitations
Guidelines and New Source Performance Standards for the
Major Organic Products. U^. S. Environmental Protection
Agency.! EPA 440/1-73/009; December, 1973
oEment Document for Effluent Limitations Guidelines
and Standards of Performance - Organic Chemicals Industry
Draft. Prepared by Prepared by_ Roy F. Westgn^ Inc. for U._
S. Environmental Protection Agency ; Contract No. 68-01-1509^
JuneA 19.73^
Hager, Donald. "A Survey of Industrial Wastewater
Treatment by Granular Activated Carbon." Presented at the
4th Joint Chemical Engineering Conference; Vancouver,
British Columbia; September 10, 1973.
Kennedy, D. C. , and others. "A New Adsorption/ Ion
Exchange Process for Treating Dye Waste Effluents." Rohm
and Haas Company; Philadelphia, Pennsylvania.
Pattison, E. Scott, editor. Fatty Acids and Their
Industrial Applications. New York: Marcel Dekker, Inc. ,
1968.
373
-------
Bibliography From the Phase I Development Document
Albright, P.N., "The Present Status of Phenol Waste
Treatment" Public Works, Vol. 98, No. 6 (June 1967), 124-
127.
"Are You Drinking Biorefractories Too?" Envi ronmenta1
Science and Technology, Vol. 7 No.l (January 1973), 14-15.
Bengly, M., "The Disposal of Liquid and Solid Effluents and
Oil Refineries." Proceedings of 21st Industrial Waste
Conference, Purdue University (May 1966), 759-767.
Beychok, M.R., "Wastewater Treatment." Hydrocarbon
Processing, Vol. 50, No. 12 (December 1971), 109-112.
Black, G.M., and Schoonman, W., "Save Water: Air Condense
Steam." Hydro-carbon Processing, Vol. 49, No. 10 (October
1970), 101-103.
Borkowski, B., "The Catalytic Oxidation of Phenols and Other
Impurities in Evaporated Effluents." Water Research, Vol. 1
(Pergamon Press, 1967), 367-385.
Browning, J.E., ed., "Activated Carbon Bids for Wastewater
Treatment Jobs." Chemical Engineering, Vol. 77, No.9
(September 1970), 32-34.
Games, A., Eller, J.M., and Martin, J.C. , "Reuse of
Refinery and Petrochemical Wastewaters." Industrial Water
Engineering, Vol. 9, No. 3 (June/July 1972), 25-29.
lDonal Hager, "A Survey of Industrial Wastewater Treatment
by Granular Activated Carbon" Presented at the 4th Joint
Chemical Engineering Conference; Vancouver, British
Columbia; Sept. 10, 1973.
Dorris, T.C., Patterson, D., and Copeland, B.J., "Oil
Refinery Effluent Treatment in Ponds." Journal of the Water
Pollution Control Federation, Vol. 35, No. 7 (July 1963) ,
932-939.
Easthagen, J.H., Skrylov, V., and Purvis, A.L., "Development
of Refinery Wastewater Control at Pascagoula, Mississippi."
Journal of Water Pollution Control Federation, Vol. 37, No.
12 (December 1965), 1671-1678.
374
-------
Eisenhauer, H.R., "Increased Rate and Efficiency of Phenolic
Waste Ozonization." Journal of Water Pollution Control
Federation, Vol. 43, No. 2 (February 1971), 200-202.
Elkin, H.F., "Activated Sludge Process Applications to
Refinery Effluent Waters." sewage and Industrial Wastes,
Vol. 28, No. 9 (September 1956), 1122-1129.
Emery, R.M., Welch, E.B., and Christman, R.F., "The Total
Organic Carbon Analyzer and Its Application to Water
Research." Journal of Water Pollution Control Federation,
Vol. 43, No. 9 (September 1971), 1834-1844.
Ewing, R.C., "Modern Waste Treatment Plant," Oil and Gas
Journal, Vol. 68, No. 9 (September 1970), 66-69. (June
1960), 377-379.
Figueroa, L.O., "Water Pollution Control at Phillips Puerto
Rico Petrochemical Complex." Chemical Engineering, Vol. 67,
No. 6 (June 1960), 377-379
Franzen, A.E., Shogan, V.G., and Grutsch, J.F., "Successful
Tertiary Treatment at American." Oil and Gas Journal, Vol.
70, No. 4 (April 1972), 48-49.
Gilliam, A.S., and Anderegy, F.C., "Biological Disposal of
Refinery Wastes." Proceedings of 14th Industrial Waste
Conference, Purdue University (May 1959), 145-154.
Gloyna, E.F., Brady, S.O., and Lyles, H., "Use of Aerated
Lagoons and Ponds in Refinery and Chemical Waste Treatment."
Journal of Water Pollution Control Federation, Vol. 41, No.
3 (March 1969), 429-438.
Gloyna, E.F., Ford, D.L., and Eller, J., "Water Reuse in
Industry." Journal of Water Pollution Control Federation,
Vol. 42, No. 2 (February 1970), 237-242.
Gazzi, L., and Pasero, R., "Selection." Hydrocarbon
Processing, Vol. 49, No. 10 (October 1970), 83-90.
Harris, A.J., "Water Pollution Control Activities of the
Central Ontario Lakeshore Refineries." Journal of Water
Pollution Control Federation, Vol. 35, No. 9 (September
1963), 1154-1165.
Hart, J.A., "Air Flotation Treatment and Reuse of Refinery
Waste Water." Proceedings of 25th Industrial Waste
Conference, Purdue University (May 1970), 1-14.
375
-------
Hart, J.A., "On Improving Wastewater Quality." Industrial
Water Engineering, Vol. 7, No. 8 (September/October 1970),
20-26.
Henshaw, T.B., "Adsorption/Filtration Plant Cuts Phenols
from Effluent." Chemical Engineering, Vol. 78, No. 5 (May
1971), 47-55.
Hovious, J.C., Conway, R.A., and Garze, C.W., "Anaerobic
Lagoon Pretreatment of Petrochemical Wastes." Journal of
Water Pollution Control Federation, Vol. 45, No. 1 (January
1973), 71-84.
Jaeschke, L., and Trobisch, K., "Treat HPI Wastes
Biologically." Hydrocarbon Processing, Vol. 46, No. 7 (July
1967), 11-115.
Kent, J.A., Industrial Chemistry, Reinhold Publishing Corp.,
New York (1962).
Kumke, G.W., Conway, R.A., and Creagh, J.P., "Compact
Activated Sludge Treatment of combined Petrochemical
Municipal Waste." Water and Wastes Engineering, Vol. 9, No.
11 (November 1972), 342-351.
Lewis, W.L., "New Process To Remove Phenols from
Wastewater." Journal of Water Pollution Control Federation,
Vol. 40, No. 5 (May 1968), 869-872.
Lund, H.F., ed., Industrial Pollution Control Handbook;
McGraw-Hill, Inc. New York (1971).
Mapstone, G.E., "Control Cooling Tower Slowdown."
Hydrocarbon Processing, Vol. 46, No. 1 (January 1967), 155-
160.
McKinney, R.E., "Biological Treatment Systems for Refinery
Wastes." Journal of Water Pollution Control Federation, Vol.
36, No. 3 (March 1967), 346-359.
McPhee, W.T., and Smith, A.R., "From Refinery Wastes to Pure
Water." Proceedings of 16th Industrial Waste Conference,
Purdue University (May 1961), 311-326.
"Methods for Chemical Analysis of Water and Wastes."
Environmental Protection Agency, National Environmental
Research Center, Analytical Quality Control Laboratory,
Cincinnati, Ohio (1971) .
376
-------
Morissey, A.J., and LaRocca, S.A., "Wastewater Load
Evaluated at a MultiProduct Organic Chemical Plant."
Industrial Water Engineering, Vol. 7, No. 5 (May 1970), 173-
178.
Mytelka, A.I., and Manganelli, R., "Energy-Induced Changes
in an Azo Dyesstuff Waste." journal of Water Pollution
Control Federation, Vol. 40, No. 2 (February 1968), 260-268.
1972-73 OPD Chemical Buyers Directory, Chemical Marketing
Reporter. Schnell Publishing Co., Inc., New York (1973).
Parmelley, C.S., and Fox, R.D., "Reuse Comes our Ahead."
Water and Wastes Engineering, Vol. 9, No. 11 (November
1972).
Paulson, E.G., "The War on Pollution." Oil and Gas Journal,
Vol. 68, No. 6 (June 1970), 85-92.
Perry, J.H., Chemical Engineer's Handbook, McGraw-Hill, Inc.
New York (1963).
Polss, P., "What Additives Do for Gasoline." Hydrocarbon
Processing, Vol. 52, No. 2 (February 1973), 61-68.
Prather, V., "Advanced Treatment of Petroleum Refinery
Wastewater by Autoxidation." Journal of Water Pollution
Control Federation, Vol. 42, No. 4 (April 1970), 596-603.
Pursell, W.L., and Miller R.B., "Waste Treatment of Shelly
Oil Company's ElDorado, Kansas Refinery." Proceedings of
16th Industrial Waste Conference, Purdue University (May
1961), 292-303.
Rainbow, C.A. , "Industrial Wastewater Reclamation."
Proceedings of 23rd Industrial Waste Conference, Purdue
University (May 1968), 1-9.
Rey, G., Lacy, W.I., and Cywin, A., "Industrial Water Reuse;
Future Pollution Solution." Environmental Science and
Technology, Vol. 5, No. 9 (September 1971), 842-845.
Rose, B.A., "Water Conservation Reduces Load." Industrial
Water Engineering, Vol. 6, No. 9 (September 1969), 4-8.
Rose, W.L., Gorringe, G.E., "Activated Sludge Plant Handles
Loading Variations." Oil and Gas Journal, Vol. 70, No. 10
(October 1972), 62-65.
377
-------
Ross, W.K., and Sheppard, A.A., "Biological Oxidation of
Petroleum Phenolic Waste Waters." Proceedings of 10th
Industrial Waste Conference, Purdue Univeraity (May 1955),
106-119.
Santoleri, J.J., "Chlorinated Hydrocarbon Waste." Chemical
Engineering Process, Vol. 69, No. 1 (January 1973) , 68-74.
Sawyer, G.N., "Fertilization of Lakes by Agriculture and
Urban Drainage." Journal of New England Water Works
Association, (1949).
"Sequential Gasification." Oil and Gas Journal, Vol. 70,
No. 10 (October 1972) , 116-117.
Shreve, R.N., Chemical Process Industries, third edition;
McGraw-Hill, Inc., New York (1956).
Smallwood, D.S., Ramanathan, M., and Dougherty, J.H.,
"Reference Effluent Guidelines for Organic Chemical
Industries, Process Narratives." Roy F. Weston, Inc. report
to Environmental Protection Agency, Washington, D.C.,
Contract No. 14-12-963, (Unpublished).
Snoeyink, V.L., Weber, W.J., and Mark, H.B., "Sorption of
Phenol and Nitrophenol by Active Carbon." Environmental
Science and Technology, Vol. 3, No. 10 (October 1969), 918-
926.
"Sohio Uses Sewage-Plant Effluent as Stop Feedwater." Oil
and Gas Journal, Vol. 70, No. 2 (February 1972), 80-82.
"Standard Methods for the Examination of Water and
Wastewater." American Public Health Association, Inc., New
York (1971) .
Steck, W., "The treatment of Refinery Wastewater with
Particular consideration of Phenolic Streams." Proceedings
of 21st Industrial Waste conference, Purdue University (May
1966), 783-790.
Stroud, P.W., Sorg, L.V., Lamkin, J.C., "The First Large
Industrial Waste Treatment Plant on the Missouri River."
Proceedings of 18th Industrial Waste Conference, Purdue
University (May 1963), 460-475.
Taras, M.J., ed., Standards Methods for the Examination of
Water and Wastewater American Public Health Assocation,
Washington, D.C., (1971).
378
-------
Thompson, C.S., Stock, J., and Mehta, D.L., "Cost and
Operating Factors for Treatment of Oily Waste Water." Oil
and Gas Journal, Vol. 70, No. 11 (November 1972), 53-56.
Thompson, S.J., "Techniques for Reducing Refinery Waste
Water." Oil and Gas Journal, Vol. 68, No. 10 (October 1970),
93-98.
Vania, G.B., Bhatla, M.N., Thompson, A.F., and Bralston,
C.W., "Process Development, Design, and Full-Scale
Operational Experience at a Petrochemical Manufacturing
Wastewater Treatment Plant." Proceedings of 44th Conference
of the Water Pollution Control Conference (October 1971), 1-
25.
Water; Atmospheric Analysis, Part 23, "Standard Method of
Test for Bio-Chemical Oxygen Demand of Industrial Water and
Industrial Waste Water." 1970 Annual Book of ASTM
Standards, American Society for Testing and Materials,
Philadelphia, Pennsylvania (1970).
"Water Quality Criteria." State Water Quality Control board.
Publication No. 3-A, Sacramento, California (1963).
Wigren, A.A., and Burton, F.L., "Refinery Wastewater
Control." Journal of Water Pollution Control Federation,
Vol. 44, No. 1 (January 1972), 117-128.
379
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Summary of EPA Research Development and
Demonstration Projects Utilizing Activated
Carbon Adsorption Technology
EPA Advanced Wastewater Treatment Demonstration
Grant No. 17080 EDV, "Tertiory Treatment by Lime
Addition at Santee, California, "Santee County
Water District, Santee, California, January 12, 1966.
EPA Advanced Wastewater Treatment Demonstration Grant
No. 802719, "Interim Wastewater Treatment Plant
Demonstration, Covington Kentucky, "Campbell and Kenton
Counties Sanitation District, July 23, 1973.
EPA Advanced Wastewater Treatment Demonstration
Grant No. 80266, "Physical Chemical Treatment Evaluation",
Metropolitan Sewer Board Minneapolis, St. Paul Minn.,
January 1, 1974.
EPA Storm and Combined Sewer Research Grant No. 802433
Rice University, Houston, Texas, "Maximum Utilization of
Water Resources in a Planned Community, July 16, 1973.
EPA Industrial Research Grant No. 17020 EPF, "Adsorption
from Aqueaus Solution", University of Michigan, Ann Arbor
Michigan, October 1, 1969.
EPA Industrial Demonstration Grant No. 12050GXE, "Treatment
of Oil Refinery Wastewaters for Reuse Using a Sand Filter
Activated Carbon System, B.P. Oil Company, Marcus Hook,
Pennsylvania January 1, 1971.
EPA Industrial Demonstration Grant No. 12020EAS "Recondition
and Reuse of Organically Contaminated Waste Sodium Chloride
Brines, Dow Chemical Company, Midland, Michigan, January 6, 1969,
EPA Advanced Wastewater Treatment Demonstration Grant No.
11060 EGP, "Advanced Waste Treatment at Painesville, Ohio,
City of Painesville, Ohio, December 15, 1969.
EPA Research Grant No. 12040 HPK, "Organic compounds
in Pulp Mill Lagoon Discharge", University of Washington.
380
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EPA Research Study No. 21ACU07, "Development of Analog
Chemical Treatment", EPA NERC Cincinnati, Ohio, January 7, 1972
EPA Research STudy No. 21 ABD 06, "Process Modification
to Enhance Removal of Heavy Metals, NERC Cincinnati, Ohio
January Ht 1973.
EPA Advanced Wastewater Treatment Demonstration Grant
No. 11010 EHI, "Teritory Treatment of Combined Storm
Water Sanitary Relief Discharge and Sewage Treatment
Plant Effluent", Sanitary District of East Chicago,
January 12, 1966.
EPA Advanced Waste Treatment Demo Grant No. 11010 DAB,
"Chemical Clarification and Carbon Filtration and Adsorption
as Secondary Treatment for Rocky River Wastewater Treatment
Plant, Cuyahoga County, Ohio Sewer District, August 16, 1968.
EPA Industrial Demonstration Grant No. 801U31, "An Activated
Carbon Secondary Treatment System for Purification of a
Chemical Plant Wastewater for maximum Reuse, "Hercules, Inc.,
January 3, 1973.
EPA Demonstration Grant No. 80055U, "Carbon Adsorption and
Regeneration for Petrochemical Waste Treatment", University
of Missouri, Columbia, Missouri, January 6, 1972.
EPA Research Contract No. 68-01-0183 "Physical Chemical
Treatment of Municipal Waste", Envirotech Corporation
Salt Lake City, Utah, July t, 1972.
EPA Research Contract No. 68-01-0137, "Development
and Demonstration of Device for on Board Treatment
of Wastes from Vessels," AWT Systems Inc., Wilmington
Delaware, March 6, 1971
EPA Research Contract No. 68-01-0130, "Device for on
Board Treatment of Wastes from Vessels", Fairs banks
Morse, Inc., Beloit, Wisconsin, March 6, 1971.
EPA Research Contract No. 68-01-0099, "Development of
Modular Transportable Prototype System for Treating
Spilled Hazardous Materials", Hernord, Inc., Milwaukee,
Wisconsin, June 29, 1971.
381
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EPA Research Contract No. 68-01-0077, "Process for
Housing and Community Development Industries", Levitt
and Son, Nassau County, New York, June 15, 1971.
EPA Research Contract No. 68-01-0013, "Waste Heat
Utilization in Waste Water Treatment", URS Research
Company, San Mateo, California, December 31, 1970.
EPA Research Contract No. 58-01-0901, "Study of
Improvements in Granular Carbon Adsorption Process",
FMC Corporation, Princeton, New Jersey, June 26, 1970.
EPA Advanced Waste Treatment Contract No. 58-01-0441,
"Carbon Adsorption and Electro dialipes for Demineralization
at Santee California," Santee Coutny Water District,
Santee California, June 29, 1968.
EPA Research Contract No. 58-01-0400, "Activated Carbon
Powder Treatment in Slurry Clarifiers", Infilco, Fullers
Company, Tucson, Arizona, June 9, 1968.
EPA Research Contract No. 58-01-0075, "Study of Powdered
Carbons for Waste Water Treatment, "West Virginia Pulp
and Paper Company, Covington, Virginia, June 29, 1967.
EPA Research Study No. 21ABK-31, "Treatability of Organic
Compounds", EPA NERC Cincinnati, Ohio January 7, 1973.
EPA Research Study No. 21 ABK 16, "Treatability of Organic
EPA Research Study No. 21 ACP 09, "Removal of Toxi Metals
in Physical Chemical Pilot Plant", EPA NERC Cincinnati, Ohio
January 1, 1972.
EPA Research Study No. 16 ACG-05, "Identify Pollutants
in Physical Chemical Treated Wastes", EPA NERC Corvallis,
Oregon, January 8, 1971.
EPA Advanced Waste Treatment Demonstration Grant No. 800685,
"A Demonstration of Enhancement of Effluent from Trickling
Filter Plant", City of Richardson, Texas, December 24, 1971.
EPA Advanced Waste Treatment Demonstration Grant No. 801026,
"Removal of Heavy Metals by Waste Water Treatment Processes",
City of Dallas, Texas, January 2, 1972.
382
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EPA Advanced Waste Treatment Demonstration Grant No. 801401,
"Piscataway Model Advanced Waste Treatment Plant", Washington
Suburban Sanitary Commission, Hyattsville, Maryland, January
1, 1967.
EPA Research Grant No. 800661, "Oxidation Mechanisms on
Supported Chromia Catalysts, "Purdue Research Foundation,
Lafayette, Indiana, January 6, 1970.
EPA Research Grant No. 12130 DRO, "Deep Water Pilot Plant
Treatability Study", Delaware River Basin Commission,
Trenton, New Jersey, July, 1971.
383
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SECTION XVI
GLOSSARY AND ABBREVIATIONS
Act
The Federal Water Pollution Act Amendments of 1972.
In the presence of oxygen.
Living or active in absence of free oxygen.
Aguatic_Li f e
All living forms in natural waters, including plants, fish,
shellfish, and lower forms of animal life.
Hydrogen compounds involving a 6-carbon, benzene ring
structure.
Best^Available_Technoj,ogY_EconomicallY_Achievable_iBATEA).
Treatment required by July 1, 1983 for industrial discharge
to surface waters as defined by section 301 (b) (2) (A) of
the Act.
Best_Pra^icable_Contrgl_Technglog^_CurrentlY_Achievable_JBPCTCAX
Treatment required by July 1, 1977 for industrial dsicharge
to surface waters as defined by section 301 (b) (1) (A) of
the Act.
Best Available_Demonstrated_Technology JBADT^
Treatment required for new source as defined by section 306
of the Act.
Oxygen used by bacteria in consuming a waste substance.
385
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Slowdown
A discharge from a system, designed to prevent a buildup of
some material, as in boiler and cooling tower to control
dissolved solids.
Material which, if recovered, would accrue some economic
benefit, but not necessarily enough to cover the cost of
recovery.
Capj.tal_Cgsts
Financial charges which are computed as the cost of capital
times the capital expenditures for pollution control.
Catalyst
A substance which can change the rate of a chemical
reaction, but which is not itself involved in the reaction.
CateggrY_and_Subcategory
Divisions of a particular industry which processed different
traits which affect water quality and treatability.
Chemical_Oxy.gen_Demand __ (COD).
Oxygen consumed through chemical oxidation of a waste.
Clarification
The process of removing undissolved materials from a liquid.
Specifically, removal of solids either by settling or
filtration.
Effluent
The flow of waste waters from a plant or wash water
treatment plant
The cost reflecting the deterioration of a capital asset
over its useful life.
End-of-Pipe Treatment
386
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Treatment of overall refinery wastes, as distinguished from
treatment of individual processing units.
Filtration
Removal of solid particules or liquids from other liquids or
gas streams by passing the liquid or gas stream through a
filter media.
Industrial^ Waste
All wastes streams within a plant. Included are contact and
noncontact waters. No included are wastes typically
considered to be sanitary wastes.
Investment_Costs
The capital expenditures required to bring the treatment of
control technology into operation. These include the
traditional expenditures such as design; purchase of land
and materials; site preparation; construction and
installation; etc., plus any additional expenses required to
bring the technology into operation including expenditures
to establish related necessary solid waste disposal.
New_Source
Any building, structure, facility or investment from which
there is or may be a discharge of pollutants and whose
contribution is commercial after publication of the proposed
regulation.
EH
A measure of the relative acidity or alkalinity of water. A
pH of 7.0 indicates a neutral condition. A greater pH
indicates alkalinity and a lower pH indicates acidity. A
one unit change in pH indicates 10 fold change in acidity
and alkalinity.
Pretreatment
Treatment proved prior to discharge to a publicly owned
treatment works.
Process_Effluent_or_Discharge
The volume of water emerging from a particular use in the
plant.
387
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PI ant ^Ef fluent or Discharge After^Treatment
The volume of waste water discharge from the industrial
plant. In this definition, any waste treatment device is
considered part of the industrial plant.
^ Waste _ Load
Untreated waste effluent or waste effluents.
Biological treatment provided beyond primary clarification.
Sludge
The settled solids from a thickener or clarifier.
Generally, almost any flocculated settled mass.
Sur f ace^Wat er s
Navigable waters. The waters of the United States,
including the territorial seas.
Total_Susjeended_Sglids_j[TSSl,
Any solids found in waste water or in the stream which in
most cases can be removed by filtration. The origin of
suspended matter may be man-made wastes or natural sources
such as silt from erosion.
Waste Discharged
The amount (usually expressed as weight) of some residual
substance generated by a plant process or the plant as whole
and which is suspended or dissolved in water. This quantity
is measured before treatment.
Total amount of pollutant substance, generally expressed as
pounds per day.
388
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Abbreviations
AL - Aerated Lagoon
AS - Activated Sludge
BADT - Best Available Demonstrated Technology
BATEA - Best Available Technology Economically Achievable
BPCTCA - Best Practicable Control Technology Currently Available
BOD - Biochemical Oxygen Demand
BTX - Benzene-Toluene-Xylene mixture
COD - Chemical Oxygen Demand
cu m - cubic meter(s)
DAF - Dissolved Air Flotation
DO - Dissolved Oxygen
gpm - Gallons per minute
k - thousand(e.g., thousand cubic meters)
kg - Kilogram(s)
1 - liter
Ib - pound (s)
LPG - Liguified Petroleum Gas
M - Thousand (e.g., thousand barrels)
mgd - Millions gallons per day
mg/1 - Milligrams per liter (parts per million)
MM - Million (e.g., million pounds)
psig - pounds per sguare inch, gauge (above 14.7 psig)
RWL - Raw Waste Load
sec - Second-unit of time
389
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scf - Standard cubic feet of gas at 60°F and 14.7 psig
SIC - Standard Industrial Classification
SS - Suspended Solids
TOC - Total Organic Carbon
TSS - Total Suspended Solids
VSS - Volatile Suspended Solids
390
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METRIC TABLE
CONVERSION TABLE
MULTIPLY (ENGLISH UNITS)
ENGLISH UNIT ABBREVIATION
acre ac
acre - feet ac ft
British Thermal
Unit BTU
British Thermal
Unit/pound BTU/It
cubic feet/minute cfm
cubic feet/second cfs
cubic feet cu ft
cubic feet cu ft
cubic inches cu in
degree Fahrenheit °F
feet ft
gallon gal
gall en/minute gpm
horsepower hp
inches in
inches ct mercury in Hg
pounds Ib
million gallons/day mgd
mile mi
pound/square
inch (gauge) psig
square feet sq ft
square inches sq in
ton (short) ton
yard yd
* Actual conversion,, not a multiplier
by TO OBTAIN (METRIC UNITS)
CONVERSION ABBREVIATION METRIC UNIT
hectares
cubic meters
kilogram - calories
ki 1 ograni co "iori es/ki 1 ogram
cubic meters/miriute
cubic meters/minute
cubic meters
1i ters
cubic centimeters
degree Centigrade
meters
liters
1i tors/second
ki1lowatts
centimeters
atmospheres
kilograms
cubic meters/day
kilometer
atmospheres (absolute)
square meters
square centimeters
metric ton (1000 kilograms)
meter
0.405
1233.5
0.252
0.555
0.028
1.7
0.028
28.32
16.39
0.555(*F-32)*
0.3048
3.785
0.0631
0.7457
2.54
0.03342
0.454
3,785
1.509
(0.06805 osig +1)*
0.0929
6.452
0.907
0.9144
ha
cu rn
kg ca.1
kg cal/k.g
cu m/mi n
cu m/min
cu m
1
cu cm
°C
m
1
I/sec
kw
cm
atm
kg
cu rn/day
krn
atm
sq m
sq cm
kkg
m
391
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U.S. ENVIRONMENTAL PROTECTION AGENCY (A-107)
WASHINGTON, D.C. 20460
POSTAGE AND FEES PAID
ENVIRONMENTAL PROTECTION AGENCY
EPA-335
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