LPA 440/1-74/18
Development Document for
Proposed Effluent Limitations Guidelines
and New Source Performance Standards
\
for the
SOAP and DETERGENT
Manufacturing
Point Source Category
\
**
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
DECEMBER 1973
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DEVELOPMENT DOCUMENT
for
PROPOSED EFFLUENT LIMITATIONS GUIDELINES
and
NEW SOURCE PERFORMANCE STANDARDS
SOAP AND DETERGENT MANUFACTURING
POINT SOURCE CATEGORY
Russell E. Train
Administrator
Robert L. Sansom
Assistant Administrator for Air & Water Programs
Allen Cywin
Director, Effluent Guidelines Division
Richard T. Gregg
Project Officer
Dec ember , 1973
Effluent Guidelines Division
Office of Air and Water Programs
U.S. Environmental Protection Agency
Washington, D.C. 20460
M.S. Environmental Protection
5, UbrarycPL-i2J)
I2t»
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ABSTRACT
This document presents the findings of an extensive stuay of the soap
and detergent manufacturing industry by Colin A. Houston and Associates
for the Environmental Protection Agency for the purpose of developing
effluent limitations guidelines, Federal standards of performance, and
pretreatment standards for the industry to implement Sections 304, 306
and 307 of the Federal Water Pollution Control Act Amendments of 1972.
Effluent limitations guidelines recommended herein set forth the degree
of effluent reduction attainable through the application of the best
practicable control technology currently available and the degree of
effluent reduction attainable through application of the best available
technology economically achievable which must be achieved by existing
point sources by July 1, 1977, and July 1, 1983, respectively. The
Standards of Performance for new sources recommended herein set the
degree of effluent reduction which is achievable through application of
the best available demonstrated control technology, processes, operating
methods, or other alternatives.
The development of data and recommendations in the document relate to
the nineteen subcategories into which the industry was divided on the
basis of raw waste loads and appropriate control and treatment
technology. separate effluent limitations are proposed for each
subcategory on the basis of raw waste load control and end-of-pipe
treatment achievable by suggested model systems.
Supportive data and rationales for development of the proposed effluent
limitations guidelines and standards of performance are contained in
this report. Potential approaches for achieving the limitations levels
and their associated costs are discussed.
ill
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CONTENTS
Section page
I CONCLUSIONS 1
General 1
Categorization 2
History and Source of Data 3
Integrated Plants 3
Potential Developments 4
II RECOMMENDATIONS 5
III INTRODUCTION 11
Purpose and Authority 11
Limitations Guidelines and Standards
of Performance
General Description of the Industry 13
Historical 13
Companies and Markets 14
Industrial Cleaning Compounds 16
Sales and Production 16
Physical Plant 16
Trade Practices 17
Industry Problems 17
Future Trends 18
Soap Process Descriptions 18
Soap Manufacture by Batch Kettle 18
Fatty Acid Manufacture by Fat Splitting 23
Soap From Fatty Acid Neutralization 23
Glycerine Recovery 26
Soap Flakes and Powders 28
Bar Soap 30
Liquid Soap 32
Detergent Process Descriptions 34
Oleum Sulfonation/Sulfation 35
Air-S03_ Sulfation/Sulfonation 35
S03_ Solvent and Vacuum Sulfonation 38
Sulfamic Acid Sulfation 38
Chlorosulfonic Acid Sulfation 38
Neutralization of Sulfuric Acid Esters 38
and Sulfonic Acids
Spray Dried Detergents 43
Liquid Detergents 45
Dry Detergent Blending 45
Drum Dried Detergents 48
Detergent Bars and Cakes 48
Formulations 51
Iv
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Section
IV INDUSTRY CATEGORIZATION
Introduction • 55
Categorization 56
V WASTE CHARACTERIZATION 59
Introduction 59
Soap Manufacture by Batch Kettle 59
Fatty Acids by Fat Splitting 60
Soap by Fatty Acid Neutralization 62
Glycerine Recovery 62
Soap Flakes and Powders 63
Bar Soaps 64
Liquid Soaps 64
Oleum Sulfonation and Sulfation 65
Air-SO^ Sulfonation and Sulfation 66
S03 Solvent and Vacuum Sulfonation 66
SuTfamic Acid Sulfation 67
Chlorosulfonic Acid Sulfation 68
Neutralization of Sulfuric Acid Esters 68
and Sulfonic Acids
Spray Dried Detergents 69
Liquid Detergent Manufacture 70
Detergent Manufacturing by Dry Blending 72
Drum Dried Detergents 72
Detergent Bars and Cakes 72
VI POLLUTANT PARAMETERS 75
Introduction 75
Control Parameter Recommendations 75
Biochemical Oxygen Demand 75
Chemical Oxygen Demand 76
Suspended Solids 76
Surfactants (MBAS) 76
Oil and Grease 76
pH 77
Parameters Omitted 77
Nitrogen 77
Phosphorus and Boron 77
Scope of Parameter Measurements - 77
By Process
Soap Manufacture by Batch Kettle 78
Fatty Acids by Fat Splitting 78
Soap by Fatty Acid Neutralization 78
Glycerine Recovery 79
Soap Flakes and Powders 79
Bar Soaps 79
Liquid Soap 79
V
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Sectio" Page
Oleum Sulfonation and Sulfation 30
Air-S03_ Sulfation and Sulfonation 30
SO^ Solvent and Vacuum Sulfonation 80
Sulfamic Acid Sulfation 30
Neutralization of Sulfuric Acid Esters si
and Sulfonic Acids
Spray Dried Detergents 51
Liquid Detergents 82
Dry Detergent Blending 52
Drum Dried Detergents 32
Detergent Bars and Cakes 32
Industrial Cleaners 82
VII CONTROL AND TREATMENT TECHNOLOGY
85
Introduction 35
Nature of Pollutants 35
Discussion of Treatment Techniques 37
Oil and Grease Removal 37
Coagulation and Sedimentation gg
Byconversion Systems go
Carbon Absorption Systems 90
Filtration for Removal of Suspended 90
Solids
Dissolved Solids Removal 90
Other Treatment Technique Considerations 91
Special Operational Aspects of Control 92
Technology
Solid Waste Generation Associated with 95
Treatment Technology
VIII COST, ENERGY AND NONWATER QUALITY ASPECTS 97
In-Plant Control 97
Impurities Removal 98
By-product/Degradation Product Control 99
Dilute Product from Cleanouts, Leaks 99
and Spills
End-of-Pipe Treatment 100
Energy Requirements 105
Nonwater Quality Aspects 105
Implementation of Treatment Plans 105
IX BEST PRACTICABLE CONTROL TECHNOLOGY 109
CURRENTLY AVAILABLE
Introduction 109
Soap Manufacture by Batch Kettle 110
Fatty Acid Manufacture by Fat Splitting 112
Fatty Acid Hydrogenation 115
Soap from Fatty Acid Neutralization 117
Glycerine Recovery 118
Soap Flake and Powders 121
VI
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Section
Bar Soaps 122
Liquid 123
Oleum Sulfonation and Sulfation 124
Air-SO^ Sulfation and Sulfonation 126
S03_ Solvent and Vacuum Sulfonation 127
Sulfamic Acid Sulfation 128
Chlorosulfonic Acid Sulfation 130
Neutralization of Sulfuric Acid Esters 131
and Sulfonic Acids
Spray Dried Detergents 207
Liquid Detergent Manufacture 136
Dry Detergent Blending 138
Drum Dried Detergents 139
Detergent Bars and Cakes 140
X BEST CONTROL TECHNOLOGY ECONOMICALLY 143
ACHIEVABLE
Introduction 143
Modified Soap Manufacture by Batch Kettle 145
Fatty Acid Manufacture by Fat Splitting 145
Glycerine Recovery and Concentration 149
Bar Soaps 149
Air-SO^ Sulfation and Sulfonation 152
SO^ Solvent and Vacuum Sulfonation 155
Sulfamic Acid Sulfation 155
Chlorosulfonic Acid Sulfation 155
Spray Dried Detergents 156
Liquid Detergents 156
Detergent Bars and Cakes 156
XI NEW SOURCE PERFORMANCE STANDARDS 159
AND PRETREATMENT STANDARDS
Introduction 159
Soap Manufacture by Batch Kettle 161
Soap from Fatty Acid Neutralization 162
Bar Soap - Drying 163
Solvent Process for Soap Manufacture 163
Oleum Sulfation and Sulfonation 164
Air-SO^ Sulfation and Sulfonation 164
Pretreatment Requirements 165
Fats and Oils 173
Fats and Oils - Detergent Plants 173
Zinc 174
Industrial Cleaners 174
XII ACKNOWLEDGEMENTS 175
XIII REFERENCES 177
XIV GLOSSARY 183
VI1
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TABLES
Number Page
1 Summary Value of Shipments at Manufacturers 15
Level Soaps and Detergents SIC 2841
2 Treatment Methods Used in Elimination of Pollutants 88
3 Relative Efficiency of Several Methods Used 89
in Removing Pollutants
4 Range of Water Use by Process 97
5 Cost and Energy Requirements Associated with 101
Various Treatment Methods
6 Cost of Sludge Conditioning and Disposal Operations 107
7-1 Best Available Technology Economically Achievable 143
Guidelines Reflecting No Change From Best Prac-
ticable Control Technology Currently Available
7-2 Best Available Technology Economically Achievable 144
Guidelines Reflecting Changes From Best Prac-
ticable Control Technology Currently Available
8 New Source Performance Standards Guidelines 160
VI11
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FIGURES
Number Title
1 Soap Manufacture by Batch Kettle 19
2 Soap Making 22
3 Fatty Acid Manufacture by Fat Splitting 24
4 Soap From Fatty Acid Neutralization 25
5 Glycerine Recovery 27
6 Soap Flakes and Powders 29
7 Bar Soaps 31
8 Liquid Soap Processing 33
9 Oleum Sulfation and Sulfonation 36
(Batch and Continuous)
10 Air-S03_ Sulfation and Sulfonation 37
(Batch and Continuous)
11 S03_ Solvent and Vacuum Sulfonation 39
12 Sulfamic Acid Sulfation 40
13 Chlorosulfonic Acid Sulfation 41
14 Neutralization of Sulfuric Acid Esters 42
and Sulfonic Acids
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Number Title page
15 Spray Dried Detergents 44
16 Liquid Detergent Manufacture 45
17 Detergent Manufacture by Dry Blending 47
18 Drum Dried Detergent 49
19 Detergent Bars and Cakes 50
20 Composite Flow Sheet Waste Treatment 93
Soap and Detergent Industry
21 Sludge Solids Handling Soap and Detergent Industry 94
22 Waste Water Sources in Soap Manufacture HO
23 Fat Splitting 112
24 Fats Recovery System 114
25 Glycerine Concentration 119
26 Soap Manufacture by Batch Kettle: Modified 146
27 Modified: Fatty Acid Manufacture by Fat Splitting 147
28 Fatty Acids Manufacture: Hydrogenation Step, 148
If Carried Out
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Number Title Page
29 Glycerine Recovery 15°
30 Concentration of 80% Glycerine to 99.5% 151
31 Continuous Detergent Slurry Processing Plant 166
High-Active Alkylate Sulfonation with Oleum
32 Continuous Detergent Slurry Processing Plant 167
Fatty Alcohol Sulfation with Oleum
33 Soap Manufacture by Continuous Saponification 168
34 Soap by Continuous Fatty Acid Neutralization 169
and Neat Soap Drying: For Bar Soaps
35 Combined Processes S03_ Sulfonation/Sulfation- 170
Continuous and Neutralization of Sulfonic or
Alkyl Sulfuric Acid Processes-Continuous
36 Fatty Alcohol Sulfation: With S03_ 171
37 Alpha-Olefin Sulfonation with S03_ 172
XI
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SECTION I
CONCLUSIONS
General
The manufacturing of soaps and synthetic detergents represents a minor
source of water pollution. The industry uses approximately 15,160
million liters a year (or 4 billion gallons a year) as process water.
The pollutants emanating from its plants are nontoxic and readily
responsive to treatment. Some exceptions to this statement exist in the
industrial surfactant area and are discussed in this report. More than
95 percent of plant effluents go to municipal treatment plants with less
than 5 percent classed as pcint sources.
Virtually all of the 5.8 billion kilograms (12.8 billion pounds) of
product estimated from these plants in 1973 is destined for tne nation's
treatment plants and waterways; the intricacies of the manufacturing
processes of this industry warrant better understanding.
Soaps and detergents are performance products. (By dictionary
definition a detergent is a cleaning agent and includes ordinary bar
soap, which is classically based on natural fat. In popular usage,
however, the term detergent excludes soap, being restricted to the
family of cleaning compounds derived largely from petrochemicals. This
report follows popular usage.) Literally thousands of chemical
compositions can be formulated which clean a surface. Detergents can be
formulated with entirely different organic and inorganic chemicals to
exhibit the same cleaning power or have the same biodegradability. They
also can be formulated to:
1. Maximize cleaning power
2. Maximize biodegradability
3. Minimize eutrophication potential in a specific recei-
ving water
4. Maximize cleaning power/unit cost
5. Minimize air or water pollutants and solid wastes
arising from the manufacturing processes.
Guidelines can be directed toward minimized water pollution from
manufacturing, but not to the extent of excluding consideration of other
factors. It is possible today to design formulas to give almost zero
discharge of pollutants from the manufacturing process. However, the
imposition of such low pollutant discharge limits on water from the
plants of the industry might result in forcing radical reformulations
with adverse effects in other areas of environmental concern. For
example, one formulation which would enable a zero discharge from a
manufacturing plant was voluntarily discarded by the industry 10 years
ago because of its poor biodegradability.
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Categorization
For the purpose of establishing effluent limitation guidelines and
standards of performance the scap and detergent industry can be divided
into 19 subcategories based on processes and products.
SOAP MANUFACTURE
PRQCESS_DESCBIPTION
Soap Manufacture - Batch Kettle and Continuous (101)
Fatty Acid Manufacture by Fat Splitting (102)
Soap From Fatty Acid Neutralization (103)
Glycerine Recovery (104)
Glycerine concentration (104A)
Glycerine Distillation (104B)
Soap Flakes & Powders (105)
Bar Soaps (106)
Liquid soap (107)
DETERGENT MANUFACTURE
PROCESS DESCRIPTION
Oleum Sulfonation & Sulfaticn (Batch & Continuous) (201)
Air S03 Sulfation and Sulfonatior. (Batch & Continu-
ous) (202)
S03 Solvent and Vacuum Sulfonaticn (203)
Sulfamic Acid Sulfation (204)
Chlorosulfonic Acid Sulfation (205)
Neutralization of Sulfuric Acid Esters & Sulfonic
Acids (206)
Spray Dried Detergents (207)
Liquid Detergent Manufacture (208)
Detergent Manufacturing By Dry Blending (209)
Drum Dried Detergents (210)
Detergent Bars & Cakes (211)
The code numbers shown after the processes are used to identify them
throughout this report.
These subcategories cover the major unit operations of the soap and
synthetic detergent industry as it is established in the Federal
Standard Industrial Classification Manual, Industry Code Number 2841.
Some special processes in the production of surfactants have beer
omitted, namely:
Amine Oxides Quaternaries Isethionates
Amides Alkyl Glyceryl Ether Hydrotropes
Taurides Sulfonates
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The categories covered in this report allow the permit granting
authority to identify the unit operations in a soap and detergent plant
and the important measurable effluents associated with each. Where
several units are present in the same plant, the permit: granting
authority can establish a maximum permissible effluent standard for a
given plant by adding the effluent allowable from each unit. Wnere a
large number of units are grouped together in a single plant it is
possible to reduce the total permissible effluent that would be arrived
at simply by adding the individual units in that site. Techniques for
such reduction are covered in the body of this report.
HISTQRY_AND_SOURCE_OF_DATA
When the study was initiated on January 16, 1973, there were no detailed
effluent studies available on this industry. A literature search
including previous EPA and state work yielded li-tle useful data. The
Corps of Engineers permit applications yielded little correlatable data
since information as to the products produced and any relationship of
product or processes to effluent flows was lacking. Another problem
then arose when it was fourd that thc soap and detergent companies
possessed little or no detailed data regarding their effluent flows.
Most effluent data from the comparie? turned out to be on combined
sewers (combining the effluent of thiet to ten process units) and hence
were of limited value. Therefore, the sample program orginally
conceived by the EPA and contractor as a program to verify literature
and company-provided information had to b-- enlarged and turned into a
major research project. Though a iela-iv-ly sound aata base was
obtained, ideally such data si-culd be obtained by composite sampling
over a period lasting from thirty days to a y-nr. Because of the great
pressure to complete this work to enable thr FPA to puolish guidelines
October 18, 1973, as called for in the Ac*, Public Law 9/-50G, it was
impossible to run any composite proaran, longer than 0:1-= week. A number
of the sample programs initiated are being continual voluntarily by the
companies and more sophisticated information has b-j-aur. to come
For publication of this report, it was nec^ssa: y to lort-c^ose use of
further data June 15, 1973. The data flov is exprct-rl to continue and,
after collation, is being turned over to thQ FPA -is received. A major
conclusion stemming from this work is the recognition or tijt necessity
of arranging for a long term EPA depository ror industry efiiuent data
so that water handling problems can be fairly and inventively dealt
with.
PJL a n t s
An important conclusion reached in this study was that integrat-d plants
having a group of several unit processes at the same plant sit= have a
substantial advantage in their ability to minimize pollution by
cascading water and working off the by-products from one process into
another unit process step. Although we have indicated many places where
we believe the permit writer should, for this reason, apply more lenient
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standards to the small one or two unit process plant, this is really an
area needing case by case evaluation.
Potential_Develop_ments
This report is written around soaps and synthetic detergents as
formulated in 1973. From a national treatment standpoint, and to lessen
the possible eutrophication impact of soap and detergent formulas, it
may be necessary to change the 1973 formulas considerably. Such changes
will result in different effluents from the production units. In the
soap and glycerine field, changes in formulation are not likely to be
very pronounced, but they are in detergent bars, powders and liquids.
Substantial changes in effluents from unit processes and hence detergent
plants may be necessary to minimize ecological impact of the end product
in specific receiving watersheds. Particularly in this industry, the
guidelines need to be reviewed periodically to adjust to improvements in
formulas.
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SECTION II
R ECOMMENDATIONS
As a result of the findings of this report the following recommendations
are made:
1. That the effluent limitations and standards of performance be based
on the level of waste reduction attainable as a 30-day moving average,
with the following values established for the designated segments of the
industry. (All values are given in terms of kilograms (kg) of pollutant
per kkg of the anhydrous product produced in the numbered process given.
As all values express weight to weight ratios the units are
interchangeable and Ib can be substituted for kg. For example, 0.6 kg
BOD5_ per kkg of product is an identical ratio to 0.6 Ib BOD5 per 1000 Ib
of product.)
Best Practicable Control Technology Currently Available
Suspended Oil &
Subcategory BOD5 COD Solids surfactants Grease
Soap Manufacture 0.60 1.50 0.40 NA 0.10
Batch Kettle
Fatty Acid 1.20 3.30 2.20 NA 0.30
Manufacture By
Fat Splitting
Hydrogenation 0.15 0.37 0.10 NA 0.10
Soap From Fatty 0.01 0.05 0.02 NA 0.01
Acid Neutrali-
zation
Glycerine Con- 1.50 4.50 0.20 NA 0.10
centration
Glycerine Dis- 0.50 1.50 0.20 NA 0.10
tillation
Soap Flakes 0.01 0.05 0.01 NA 0.01
and Powders
Bar Soaps 0.34 0.85 0.58 NA 0.04
Liquid Soaps 0.01 0.05 0.01 NA 0.01
Oleum Sulfona- 0.02 .09 0.03 0.03 0.07
tion & Sulfa-
tion (Batch &
Continuous)
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Air-S03 Sulfa- 0.30 1.35 0.03 0.30 0.05
tion S Sulfona-
tion (Batch &
Continuous)
SO3 Solvent & 0.30 1.35 0.03 0.30 0.05
Vacuum Sulfona-
tion & Sulfamic
Acid Sulfation
Chlorosulfonic 0.30 1.35 0.03 0.30 0.05
Acid Sulfation
Neutralization 0.01 0.05 0.03 O.C2 0.01
of Sulfuric Acid
Ester & Sulfonic
Acids
Spray Dried 0.01 0.05 O.C1 0.02 0.005
Detergents
(normal)
Spray Dried 0.08 0.35 0.10 0.15 0.03
Detergents
(air restrictions)
Spray Dried 0.02 0.09 0.02 0.04 0.005
Detergents
(fast turnaround)
Liquid Deter- 0.20 0.60 0.005 0.13 0.005
gent Manufacture
Detergent Manu- 0.01 0.07 O.C1 0.01 0.005
facturing by
Dry Blending
Drum Dried 0.01 0.05 0.01 0.01 0.01
Detergents
Detergent 0.70 3.30 0.20 0.50 0.02
Bars & Cakes
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Best Available Technology Economically Achievable
Suspended Oil &
Subcategory BOD5 COD Solids Surfactants Grease
Soap Manufacture 0.40 1.05 0.40 NA 0.05
Batch Kettle
Fatty Acid Manu- 0.25 0.90 0.20 NA 0.15
facture by Fat
Splitting
Hydrogenation 0.15 0.37 0.10 NA 0.10
Soap From Fatty 0.01 0.05 0.02 NA 0.01
Acid Neutrali-
zation
Glycerine Con- 0.40 1.20 0.1C NA 0.04
centration
Glycerine Dis- 0.30 0.90 0.04 NA 0.02
tillation
Soap Flakes 0.01 0.05 0.01 NA 0.01
and Powders
3ar Soaps 0.20 0.60 0.34 NA 0.03
Liquid Soap 0.01 0.05 0.01 NA 0.01
Dleum Sul- 0.02 0.09 0.03 0.03 0.07
fonation &
Sulfation
(Batch £
Continuous)
Air-S03 Sul- 0.19 0.55 0.02 0.18 0.04
fation and
Sulfonation
(Batch & Con-
tinuous)
501 Solvent 0.10 0.45 0.01 0.10 0.02
and Vacuum
3ulfonation &
Sulfamic Acid
Bulfation
:hlorosulfonic 0.15 0.75 0.02 0.15 0.03
Sulfation
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Neutralization 0.01 0.05 0.03 0.02 0.01
of Sulfuric Acid
Esters & Sulfonic
Acids
Spray Dried 0.01 0.04 0.02 0.02 0.005
Detergents (Normal)
Spray Dried 0.06 0.25 0.07 0.10 0.02
Detergents (Air
restrictions)
Spray Dried 0.02 0.07 0.02 0.02 0.005
Detergents (Fast
turnaround)
Liquid Deter- 0.05 0.22 0.005 0.05 0.005
gent Manufacture
Detergent Manu- 0.01 0.07 0.01 0.01 0.005
facturing by
Dry Blending
Drum Dried 0.01 0.05 0.01 0.01 0.01
Detergents
Detergent Bars 0.30 1.35 0.10 0.20 0.02
& Cakes
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Standards of Performance for New Sources
Suspended Oil &
Subcategory BOD5 COD Solids Surfactants Grease
Soap Manufacture 0.20 0.60 0.02 NA 0.05
Batch Kettle
Fatty Acid 0.25 0.90 0.20 NA 0.15
Manufacture by
Fat Splitting
Hydrogenation 0.15 0.37 0.10 NA 0.10
Soap From Fatty 0.01 0.05 0.02 NA 0.01
Acid Neutralization
Glycerine Con- 0.40 1.20 0.10 NA 0.04
centration
Glycerine Dis- 0.30 0.90 0.04 NA 0.02
tillation
Soap Flakes & 0.01 0.05 0.01 NA 0.01
Powders
Bar Soaps 0.20 0.60 0.34 NA 0.03
Liquid Soap 0.01 0.05 0.01 NA 0.01
Oleum Sulfonation 0.01 0.03 0.02 0.01 0.04
& Sulfation (Batch
& Continuous)
Air-S03 Sulfa- 0.09 0.40 0.02 0.09 0.02
tion & Sulfona-
tion (Batch &
Continuous)
S03 Solvent & 0.10 0.45 0.01 0.10 0.02
Vacuum Sulfonation
& Sulfamic Acid
Sulfation
Chlorosulfonic 0.15 0.75 0.02 0.15 0.03
Acid Sulfation
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Neutralization of 0.01 0.05 0.03 0.02 0.01
Sulfuric Acid
Esters 6 Sulfonic
Acids
Spray Dried 0.01 0.04 0.02 0.02 0.00
Detergents (Normal)
Spray Dried 0.06 0.25 0.07 0.10 0.02
Detergents (Air
restricted)
Spray Dried 0.02 0.07 0.02 0.02 0.005
Detergents (Fast
turnaround)
Liquid Detergent 0.05 0.22 0.005 0.05 0.005
Manufacture
Detergent Manu- 0.01 0.07 0.01 0.01 0.005
facturing by
Dry Blending
Drum Dried 0.01 0.05 0.01 0.01 0.01
Detergents
Detergent Bars 0.30 1.35 0.10 0.20 0.02
& Cakes
The pH of final discharge(s) should be within the range of
6.0-9.0 at all times.
2. For purposes of monitoring and enforcement, periods and values other
than^ those for the 30-day average should be adopted. Daily maximums
ranging from 1.5 to 3 times the 30-day average are recommended as
reflecting reliability of control and treatment.
3. A continuing effort is recommended to further study the waste water
effluent problems of the soap and detergent field, particularly
detergents. The technology is in a state of rapid flux and merits close
observation.
Basically two areas should be considered:
(a) Changes in detergent formulations and how they affect
wastes associated with manufacture and the environmental
impact resulting from use by the consumer.
(b) Control and treatment practices as they affect
water pollution, air pollution, and solid waste.
10
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SECTION III
INTRODUCTION
Authority
Section 301 (b) of the Act requires the achievement by nor later than
July 1, 1977, of effluent limitations for point sources, other than
Dublicly owned treatment works, which are based on the application of
the best practicable control technology currently available as defined
by the Administrator pursuant ro Section 304 (b) of the Act. Section
301 (b) also requires the achievement by not later than July 1, 1983, of
effluent limitations for point sources, other than publicly owned
treatment works, which are based on the application of the best
available technology economically achievable which will result in
reasonable further progress toward the national goal of eliminating the
discharge of all pollutants, as determined in accordance with
regulations issued by the Administrator pursuant to Section 304 (b) of
the Act. Section 306 of the Act requires the achievement by new sources
of a Federal standard of performance providing for the control of the
discharge of pollutants which reflects the greatest degree of effluent
reduction which the Administrator determines to be achievable through
the application of the best available demonstrated control technology,
processes, operating methods, or other alternatives, including, where
practicable, a standard permitting no discharge of pollutants.
Section 304 (b) of the Act requires the Administrator to publish within
one year of enactment of the Act, regulations providing guidelines for
effluent limitations setting forth the degree of effluent reduction
attainable through the application of the best practicable control
technology currently available and the degree of effluent reduction
attainable through the application of the best control measures and
practices economically achievable including treatmenr techniques,
process and procedure innovations, operation methods and other
alternatives. The regulations proposed herein set forth effluent
limitations guidelines pursuant to Section 304 (b) of the Act for the
soap and detergent 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. The Administrator published in the Federal Register of
January 16, 1973 (38 F.R. 1624), a list of 27 source categories. Pub-
lication of the list constituted announcement of the Administrator's
intention of establishing, under Section 306, standards of performance
applicable to new sources within the soap and detergent category, which
was included within the list published January 16, 1973.
Limitations Guidelines and Standards of Performance
11
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The effluent limitations guidelines and standards of performance
proposed herein were developed in the following manner. The point
source category was first categorized for the purpose of determining
whether separate limitations and standards are appropriate for different
segments within a point source category. Such subcategorization was
based upon raw material used, product produced, manufacturing process
employed, and other factors. The raw waste characteristics for each
subcategory were then identified. This included an analysis of (1) the
source and volume of water used in the process employed and tne sources
of waste and waste waters in rhe plant; and (2) the constituents (inclu-
ding thermal) of all waste waters including toxic constituents and other
constituents which result in taste, odor, and color in water or aquatic
organisms. The constituents of waste waters which should be subject to
effluent limitations guidelines and standards of performance were iden-
tified.
The full range of control and treatment technologies existing within
each subcategory was identified. This included an identification of
each distinct control and treatment technology, including both inplant
and end-of-process technologies, which are -xistent or capable of being
designed for each subcategory. it also included an identification in
terms of the amount of constituents (including thermal) and the
chemical, physical, and biological characteristics of pollutants, of the
effluent level resulting from the application of each of the treatment
and control technologies. The problems, limitations and reliability of
each treatment and control technology and the required implementation
time was also identified. ir addition, the non-water quality en-
vironmental impact, such as the effects of the application of such
technologies upon other pollution problems, including air, solid waste,
noise and radiation were also identified. The energy requirements of
each of the control and treatment technologies was 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 "best available demonstrated control
technology, processes, operating methods, or other alternatives." In
identifying such technologies, various factors were considered. These
included the total cost of application of technology in relation to the
effluent reduction benefits to be achieved from such application, the
age^ of ^equipment and facilities involved, the process employed, the
engineering aspects of the application of various types of control
techniques, process changes, non-water quality environmental impact
(including energy requirements) and other factors.
The data for identification and analyses were derived from a number of
sources. These sources included EPA research information, published
literature, a voluntary industrywide audit, an extensive industry plant
effluent sampling program, qualified technical consultation, and on-site
visits and interviews at exemplary soap and detergent processing plants
throughout the United States. All references used in developing the
12
-------
Guidelines for effluent limitations and standards of performance for new
sources reported herein are included in Section XIII of this document.
Gene ral_Descri2tion_of__the_ Industry
This industrial category is covered under Standard Industrial Code 2841
and includes establishments primarily engaged in the manufacture of
soap, synthetic organic detergents, inorganic alkaline detergents, or
any combination. Crude and refined glycerine from vegetable and animal
fats and oils are also included. Excluded from this category are
establishments primarily engaged in manufacturing shampoos or shaving
products and synthetic glycerine. Also excluded are specialty cleaners,
polishing and sanitation preparations.
Historical
The industry which produces products for cleaning of fabrics, dishes,
and hard surfaces goes back to the earliest recorded history. Clay
tablets found in ancient Mesopotamia dating back to the third millenium
B C , gave a soap recipe calling for a mixture of potash and oil to be
used in the making of cloth. Modern soap and synthetic detergent
formulations and business practices were shaped by a series of events
which started in the 1930s. These include the introduction of synthetic
surface active ingredients ir. the mid 1930s. There followed the war-
induced shortage of the natural ingredients for soap making such as
tallow and coconut oils and the consequent rapid increase then in the
use of synthetics.
The discovery of polyphosphate builders followed, which made synthetic
laundry products suitable replacements for soap. The scramble of soap
and detergent companies for the housewives' favor occurred during the
1950s and determined market shares of companies in the household segment
even today. Finally, there began the formulation of detergent products
to meet environmental considerations.
The first environmental reformulation consisted of a voluntary industry
switchover to more biodegradable linear benzene sulfonate surfactants to
replace the original highly branched, poorly degradable benzene
sulfonates in the 1960s. Shortly thereafter the use of phosphate
builders in detergents came under attack from environmentalists. Of the
3 nutrients, phosphorus, nitrogen and carbon, which cause eutrophication
of lakes, phosphorus appears to be the only nutrient amenable to
control. A series of events led to today's confusing ana indeterminate
situation vis-a-vis phosphate builders. Nitrilotriacetic acid use was
begun and then stopped because of fears over teratogenicity. Detergents
built with carbonates and silicates were introduced and then somewhat
squelched because some of the products represented alkalinity hazards
and there were also problems such as interference with flame retardancy,
and deposition of hard water reaction products on clothes. Today the
search for a safe, effective builder to replace phosphate continues in
full swing with citrates and multifunctional compounds such as carboxy
methylene oxy succinate getting much research effort. Other detergent
ingredients have also been the subject of concern as to their safety and
13
-------
environmental impact. Enzymes are an example, and sales of enzyme-
containing detergents suffered for a time as a result.
Compjmies_a£d_Markets
The household detergent industry is dominated by three large companies.
The largest U.S. company has about one half of the U.S. sales and
production. The next two companies in size each have about one sixth of
the U.S. market. The remaining 17 percent of the business is shared by
over 300 companies. Very few companies beyond the five largest produce
and market products across the country. The smaller companies captured
an appreciable portion of the market share of the big thre« with non-
phosphate detergents before had publicity put a damper on sales of
phosphate-free laundry detergents.
Laundry detergents are the largest category of products made by the soap
and detergent industry. The number one selling brand has held about a
25 percent share of the U.S. market for over two decades. This brand is
the industry standard for this category of product and the market leader
fights hard to maintain his level cf sales of household detergents
Other detergent companies constantly search for improved products
containing better ingredients so they can get a bigger share of this
market. The cost of the search for new and improved products has
increased greatly because of the more sophisticated safety and
environmental approaches now needed.
In considering other household cleaning products, it will be noted that
the big three producers have a less dominant position. Liquid hand
dishwashing detergents are next to laundry detergents in importance.
Although the largest companies do dominate this market tnere are many
private label products sold by supermarket chains and also quite a
number of brands marketed by smaller companies. The liquid hand
dishwashing detergent market is static in growth because cf the constant
shift toward home automatic dishwashers.
Automatic dishwashing detergents are produced in sizable amounts by
medium and small sized firms as well as the bigger detergent companies.
This category of product has grown very rapidly with the proliferation
of the home automatic dishwasher. with only a third of the nation's
households having automatic dishwashers great growth can be expected to
continue.
Household specialty cleaners of all types are produced by hundreds of
companies in successful competition with the big three. This is
possible because the specialties require less capital investment than
spray r^ned laundry detergents. Also, specialties are amenable to
smaller and localized marketing and advertising programs.
As opposed to the production of detergents, the soap producing segment
of the industry is now concerned primarily with the production of toilet
bars. A modest amount of soap is used in synthetic household detergent
manufacture, both in heavy duty solid formulations and in combination
detergent - soap bars. There is a possibility of a moderate increase in
-------
TABLE 1
SUMMARY VALUE OF SHTP-ENTS AT MANUFACTURERS LEVEL
SC&PS AND DETERGENTS SIC 2841
AFTER 1967 CENSUS OF 'lANUFACTURERS (ADJUSTED)
All Soaps
Glycerine
Natural
Alkali
Detergents
Acid Type
Cleaners
Synthetic
Org. Det.
Household
Synthetic Ore.
Det. Non-
Household
Soap and Other
Det. NSK
Grand Total
1963
(in millions)
Kiloerarns Pounds Dollars
1967
(in millions)
1973
(in millions)
gram
Ob.l
T1327F 55.0
63.6 140.0 26.0
519.0 1143,2 200.2
156.1 343.8 35.2
38.6
Kilograms Pounds Dollars Kilograms Pounds Dollars
563.1 1240.3 333.9 540.4 1190.4 413.1
65.8 145.0 36.0 68.1 150.0 35.0
670.1 1476.0 279.6 887.6 1955.0 384.5
256.1 564.0 61.7 398.6 878.0 100.7
2098.7 4622.7 1029.4 2513.5 5536.4 1235.4 3169.9 6982.2 1565.0
287.2 632.6 115.3 357.5 787.4 141.1 443.1 976.0 167.0
85.0 17.6 166.2 366.0 73.2 332.3 732.0 146.4
3768.3 8300.1 1778.7 4592.3 10115.1 2210.9 5840.1 12863.6 2813.7
-------
the marketing of laundry soap if more local ordinances prohibiting the
use of detergents were to be passed. For a number of economic reasons,
for example, the doubling of the cost of natural fats and oils used in
soap manufacture within the last year alone, it seems unlikely that soap
sales will increase significantly from their present levels.
The largest sales of bar soaps are again made by the three largest
companies. In general, other soap companies specialize in private
label, specialty soaps, and institutional sales.
Glycerine is an important product of the industry. it is made as a by-
product of soap production, and synthetically from petroleum-derived
propylene. Glycerine is an important cosmetic and food "intermediate and
many soap and detergent companies are also in these businesses.
Synthetic glycerine competes with the naturally derived product. Its
synthesis bears no relationship to the fat-derived product, but in
composition it is essentially identical.
Glycerine is a mature chemical whose use is presently growing at the
rate of 3 percent a year. The total 1972 estimated U.S. production was
158 million kilograms (348 million Ib) with exceptionally high exports
accounting for 29 million kilograms (64 million Ib) . Synthetic
glycerine (not included in SIC 2841) is estimated to have accounted for
approximately 91 million kilograms (200 million Ib) of the total produc-
tion in 1972 with natural glycerine production accounting for 68 million
kilograms (150 million Ib) . There are 3 new fat splitting plants under
construction in the U.S. which will give 3 new sources of by-product
glycerine.
In dus tr i a 1 _ Cl ea n i ng_ Compounds
Industrial cleaning compounds are also an important part of this
industry. Compounds are made for metal cleaning, textile processing,
food sanitation, and a host of other applications. Total dollar value
of the non-household cleaning market was $263 million in 1967 and is
estimated _ at $373 million for 1973. There are a host of small companies
and divisions of large companies in this business area. Most producers,
though, serve a limited market and a limited geographical area.
Sales an d_Product ion
Table I gives an estimate of dollar values and poundage produced for the
products comprising SIC 2841. It is interesting that the oldest
product, soap, still securely retains an important market; that is,
toilet and bath bars. Automatic dishwashing detergents are growing
rapidly and these products are even more vitally affected by the phos-
phate controversy than are laundry detergents.
In general, the soap and detergent industry has not integrated backwards
toward their raw materials. Basic raw materials come from a host of
supplier companies. Caustic, fats, and oils for soap making come from
16
-------
chemical and agricultural processors, although some companies do own
coconut plantations. Detergent alkylate, alcohols and non-ionic
surfactants usually corrie from large chemical and petrochemical
companies. some anionic surfactant is also produced by suppliers, but
in general the soap and detergent companies do most of their own
sulfation and sulfonation. The inorganic builders and other additives
come exclusively from supplier companies.
The three largest companies in the household market have plants in major
metropolitan areas across the country. Not only are distribution costs
important, but also the large volume of products makes it possible for
one company to build economical sized plants in a number of locations.
There are about 30 major plants for production of heavy duty laundry
detergents in the United States.
It is fairly common for the major companies to contract with other
companies for toll processing. In these arrangements the soap and
detergent company will buy synthetic detergent bases, send them to a
second company for reaction, and have the product returned for further
compounding. For example, detergent alcohols may be bought by a soap
and detergent company and then toll ethoxylated by a petrochemical com-
pany and returned to the soap and detergent company for further
processing.
Another business arrangement is the production of packaged detergents by
private label producers which are then sold by the major food chains
under their own brand names.
The capital requirements for a spray dried detergent bead plant limit
the number of these units. To be competitive, these complexes produce
volumes on the order of 13,620 kg per hour (30,000 lb per hour) and cost
up to 10 million dollars. soap making equipment can be fairly capital
intensive, especially the newer fat splitting and fatty acid
purification processes. Production of light-duty liquid detergents and
dry blended products require less capital and consequently many more
producers are found. Freight is an important consideration in shipping
liquids.
Foremost in difficulty is the phosphate problem. Large sums of money
have been spent both by detergent companies and by their suppliers to
find phosphate replacements. To date, no replacement has been found
which is entirely safe, effective, and economically feasible.
Generally, companies are reformulating with lower phosphate levels,
substituting nonionic for anionic organic surfactants, and using
additional amounts of alkaline builders like sodium carbonate and sodium
silicates.
New product development is not as frequent and fruitful as in the past.
It is much more difficult to produce new products which meet
17
-------
environmental requirements, so development money leads to fewer
products.
Future Trends
The industry is growing at a rate of 5 percent per year. It is secure
in the knowledge that its products are vitally necessary. The relative
standing of various industry members depends upon how successfully they
solve environmentally actuated formulation problems.
SOAP PROCESS DESCRIPTIONS
Each of the following process descriptions are associated with a process
flow sheet. All of the expected waste water effluents are identified in
the flow sheet by name and code number for quick reference.
SOAP MANUFACTURE BY BATCH KETTLE
Most of the soap made by this process finds its way into toiler bar form
for household usage. This use demands freedom from offensive odors, and
displeasing colors. In order to meet this requirement, the starting
fats and oils must be refined. There is a direct relationship between
quality of the fats and the quality of the finished soap.
Fat Refining emd Bleaching
There are several ways ir. which fats are refined. One of the most
frequently used methods employs activated clay as the extraction agent.
Activated clay, having a large ratio of surface area to weight, is
agitated with warm oil and filtered. Color bodies, dirt, etc., are
removed usually through a plate and frame press. The clay is disposed
of as solid waste. A small amount of clay remains in the refined fat.
The clay is often "activated" by being given an acid treatment itself by
the clay supplier and is a source of sulfate ion build-up in some soap
recycling streams.
Other ways in which fats are refined include caustic extraction, steam
stripping and proprietary aqueous chemicals.
When soap accounted for the major portion of the soap and detergent
market the Solexol process of extraction found use in refining of fats
and oils. The design of this liquid propane extraction process is based
on the diminishing solubility of fats in liquid propane with increasing
temperature. The fats are completely miscible at U8.8U C (120 F) but
become almost insoluble at 82.1U C (180 F) and most of the color bodies
precipitate.
color bodies fall to the bottom of the treating tower while decolorized
oils dissolved in liquid propane sit on the solvent (liquid propane)
layer and are recovered from the top. This process is not now used in
the United States, but should be reexamined since it offers a way to
18
-------
101 SOAP MANUFACTURE BY BATCH KETTLE
70/7 RECEIVING
STORAGE-TRANSFER
7072 FAT REFINING
AND BLEACHING
1013 SOAP BOILING
LAY
ATTYOILS:
JL.UNU 1 ; IALLUW"
A. 1 ICTIf* QOn A --
<*r\
2S04
1
\J
— *"TO SOAP
BOILING
•n
r
MIX
SET
ER
TLER
[MIXER
SETTLER
_J
BAROMETRIC
CONDENSER
-J
— u ^
CLAY
9 BLEACHING
p
k
r
FILTER
1
i
\
1
STEAM
,. STEAM
NaOH
STEAM-
SALT,,
FATTY ACIDS
L LOW GRADE
SOAP SALES
— »-
-»•
— »-
\
\
SOAP
BOILING
KETTLE
1
>X
S
1
NIGRE
PROCESSING
1
1
I
^~n
NEAT SOAP TO
*" PROCESSING
AND SALE
GLYCERINE TO
*• RECOVERY
^ LOW GRADE SOAP
*"
LOW GRADE
FATTY ACID
o
WASHOUTS
101102
WASTEWATER
101231
SOLID WASTE
101209
BAROMETRIC
CONDENSATE
101218
SEWER LYES
101319
BRINE AND ACID
WASTEWATER
707320
-------
eliminate water use and thus could again become economical as discharges
must be reduced.
Although a very old process, kettle boiling stiil makes a very
satisfactory product and in several well integrated manufacturing plants
this process has a very low discharge of waste water effluents.
Making a batch of neat soap (65 - 70 percent soap in water) can take as
long as four to six days to complete. A series of large steel tanks are
used in a counter current manner to "boil" soap. Their capacity can be
as high as 54,480 kilograms (120,000 pounds) of ingredients. Ever
weakening caustic streams are met by enriched fat so that the caustic is
essentially exhausted in the presence of fresh fat. In actual practice
the fat never leaves the tank in which it starts until it is converted
into neat soap. Just the aqueous caustic stream flows from tank to
tank.
A simplified process description for kettle boiling soap follows:
Step 1
weigh in
fats & oils
and alkali
Step 5
drain off
spent lye
and send to
recovery
Step 9
add water
and heat to
close soap
for filling
change
Step 2 Step 3
turn on add salt and
steam and saponify boil for
graining
Step 6
add water to
kettle and
boil closing
Step 10
settle and
draw off
neat soap
Step 7
add strong
alkali to
closed soap
Step 11
recycle
bottom nigre
to Step 1
Step 4
turn off
steam and
settle
Step 8
settle
and run
off lye
to Step 1
Neat soap
Step 1 - Fats and oils are weighed in. The caustic stream from the
"extreme change" of step 7 is run in as well as the nigre from step 11.
Step 2 - Live steam is customarily released into the kettle where it not
only heats up the materials but also performs the stirring function.
About three or four hours are consumed in this step.
Ste]3_3 - Graining is the act of separating the newly formed soap froir
the exhausted lye solution. An operator adds salt or salt solution
until a sample withdrawn with a trowel separates distinctly into soap
and lye. About 10 - 12 percent NaCl is required.
20
-------
Step_ 4 - About four hours are needed to completely settle the contents
into two layers.
Step__5 - The spent lye contains 7-8 percent glycerine and is sent to
the glycerine recovery unit.
Step 6 - "closed soap" is now made by adding fresh water to the kettle
and heating it to make a continuous creamy material, dissolving the
remaining glycerine and salt.
Step 7 - The "strong change" is carried out by adding fresh,
concentrated lye which saponifies the last remnants of fat. The batch
is brought to a boil again, water is added until the soap is closed,
then the lye is run in. Since the soap is not soluble in the strong
alkali it becomes grainy.
Step__8 - Steam is shut off and the batch allowed to settle for three
hours. The lye is run off and added to a beginning batch in the
"extreme kill".
Step_ 9 - Heating is again begun and water run in until the mass is
closed and boiling is continued until the soap removed on a trowel can
be poured off in a transparent sheet.
Step_ 1_0 - Heat is turned off and the batch is allowed to settle. Neat
soap is drawn off the top and run off to be processed into one of many
forms of soap products. The lower layer is the nigre which contains the
color bodies, dark soap, etc. It contains as much as 20 - 25 percent of
the kettle contents (30 - 40 percent soap). When the nigre becomes
heavily loaded with impurities it can itself be salted out, making a low
grade soap for sale.
Step__ll - Frequently the nigre is recirculated to the kettle for the
start of a new batch.
An overall schematic of the soap-making process is as follows:
The waste water from kettle boiling is essentially from the nigre
stream. The nigre is the aqueous layer which contains the color bodies
generated in the soap making process, mostly dark soaps. They are often
marketed as industrial lubricants or low grade special purpose soaps.
Where such a market can be established a kettle boil soap process is
already at the zero discharge effluent level except for the oil refining
step.
Salt Usage
In order to maintain suitable solubility for proper processing, salt is
added to the soap making process to maintain the required electrolytic
balance. Most of the salt charged into the process is ultimately
returned to it from the glycerine concentration step, which will be
discussed later. Practically every kettle boiling soap manufacturer
21
-------
f
Ket
tie
Boil
J
Spen_t^ lye
Nigre
Dark soap
to market
Evaporator
Concentrated
glycerine
Salt
SOAP MAKING
FIGURE 2
-------
concentrates his glycerine stream although only a few go on to the
distillation of glycerine.
By means of fat splitting very low grade fats and oils are upgraded to
high value products by splitting the glycerides into their two
components, fatty acids and glycerine. Fat splitting is an hydrolytic
reaction which proceeds as follows:
Fat + Water — •* Fatty Acid + Glycerine
Using a Twitchell catalyst (an aromatic sulfonic acid) and a long
residence time, fats can be split at nearly atmospheric pressures.
Today, however, most fat splitting takes place in a high pressure, high
temperature tower operated at around 34 atm and 260°C (500 psig and
500°F) .
Heated fat, 254°C (490°F) and under pressure, is fed into the bottom of
the tower and water, 204°C (400°F) and also under pressure, is fed into
the top. The two streams mix counter-currently and hydrolysis takes
place, often in the presence of a zinc or tin catalyst. At the high
remperatures employed the fat is soluble to the extent in 12 - 25
percent of water, depending upon which fat is used.
In about 90 minutes the splitting can be as high as 99 percent complete.
The glycerine by-product can be produced at a variety of concentrations
depending upon how complete a fat hydrolysis is desired. More
concentrated glycerine can be provided at some expense of fatty acid
yields.
The crude acids are flashed in a pressure reducer and then distilled at
0.0026 - 0.0039 atm (2-3 mm) pressure. The resulting product may be
subjected to an additional process step of flash hydrogenation to reduce
the amount of unsaturated acids.
SOAP FROM FATTY ACID NEUTRALIZATION (103)
Soap making by fatty acid neutralization exceeds the kettle boil process
in speed and minimization of waste water effluent. Although widely used
by the large soap producers, it is also very popular with the smaller
manufacturer .
This route from the acids is faster, simpler (no by-product dilute
glycerine stream to handle) and "cleaner" than the kettle boil process.
Distilled, partially hydrogenated acids are usually used.
The fatty acid neutralization process has several additional advantages
over the kettle boiling process. It does not have a large salt load to
recycle, and has a free alkali concentration in the order of 0.1 - 0.2
percent, contrasted with around 1 percent in the kettle boiling process.
The reaction that takes place is substantially:
23
-------
102 FATTY ACID MANUFACTURE BY FAT SPLITTING
1021 RECEIVING
STORAGE-TRANSFER
1022 FATPRETREATMENT
1023 FAT SPLITTING
1024 FATTY ACID DISTILLATION
OILS
NaOH
CLAY
AND
LYST-
*
»'
k
FAT AND
OIL
X
/
1 >< TO FAT
1 SPLITTING
I
WASTEWATER
102201
TREATING
VESSELS
f—
SPENT
CLAY
t
1
1
I
I
1
~ \
FOOTS
\
RECOVERY
1
1
i
SOLID WASTE
102209
REFINED FATS
AND OILS
STEAM
CATALYST —
FATTY ACIDS
*• AND SOAPS
WASHINGS
102221
' — «*-
PRESSURE j
REDUCTION ^
, REACTOR
t
L
I
' I
I
I
PRESSURE I
REDUCTION 3
I
FATTY
ACIDS
STE/
HYDROGEIV
IM i
i
CATALYST
CAUSTIC SODA
SULFURIC ACID-
hCBUDE
GLYCERINE
TO RECOVERY
PROCESS CONDENSATE
102322
, , BAROMETRIC
' STILL CONDENSER
FATTY ACIDS
- * ' HYDRO-
RES,- GENAT.ON
I » EMULSIO
»J NEUTRA
!
COOLING TOWER
SLOWDOWN
102404
N BREAKING
^RATION
-IZATION
=?
I
I
I
•?
5I
- I
I
I
*
-STEAM
REFINED
"FATTY ACID;
FATTY ACID
h PITCH AND
RESIDUES
BAROMETRIC
CONDENSATE
102418
SPENT CATALYST
AND WATER WASHINGS
102423
I
-------
103 SOAP FROM FATTY ACID NEUTRALIZATION
1031 RECEIVING
STORAGE-TRANSFER
1032 SAPONIFICATION
1033 RECYCLE-REPROCESSING
FATTY ACIDS
CAUSTIC SODA
SODA ASH
POTASSIUM HYDROXIDE
SODIUM CHLORIDE
STEAM
LEAKS, SPILLS, STORM
RUNOFFS, WASHOUTS.
103102
MIXER
WASTEWATER BRINES
"1 103224
I
WASHOUTS
103202
SOAP TO
STORAGE
••
REACTOR
<
-^—
1
1
1
SCRAP SOAP
CAUSTIC SODA
OFF QUALITY SOAP
TO LANDFILL 103325
WASHOUTS
103302
SEWER LYES
103326
FIGURE
Oi
-------
Caustic + Fatty Acid Soap
Often, sodium carbonate is used in place of caustic with the attendant
evolution of carbon dioxide. When liquid soaps (at room temperature)
are desired, the more soluble potassium soaps are made by starting with
potassium hydroxide. The potassium soaps are used in the familiar
liquid hand soap dispensers, in many industrial applications, and often
as lubricants.
As in kettle boiling soap manufacture, the most popular mix of acids for
bar soap is in the ratio of 20:80 20/80 coconut oil:rallow oil derived
acids. A number of distilled tall oil soaps (tall oil is derived from
the waste streams of paper manufacture) are also made for industrial
purposes.
In some cases, the soap making process is operated continuously in
tandem with a fat splitting process. The fatty acids and caustic
solution are proportionated into a reactor continuously by pumps having
a common variable speed drive. The appropriate amount of salt is also
programmed in to maintain the correct electrolyte content.
The resulting neat soap will have about 30 percent moisture.
To clarify the soap solution, the soap stream coming out of the reactor
is sometimes filtered with clay. The spent clay creates a certain
amount of solid waste and the filter press is washed our occasionally.
Otherwise this is a "clean" process.
The neat soap is further processed into bars or liquid formulations in
the same manner as the product from kettle boiling.
GLYCERlNE_PECOVERY_jQ04]_
Concentration
The kettle boiling soap process generates an aqueous stream referred to
as sweet water lyes. This stream will contain 8-10 percent glycerine,
a heavy salt concentration and some fatty materials. It is processed by
first adding a mineral acid (HCl) to reduce the alkalinity. This is
followed by the addition of alum which precipitates insoluble aluminum
soaps. The precipitate carries other impurities down with it. If the
stream were not treated with alum, there would be severe foaming in the
evaporators, and the contaminant would be carried forward into the
glycerine. The cleaned up glycerine solution is sent to the
evaporators.
The evaporators (in some smaller plants there will be only one) are
heated under reduced pressure. The partial vacuum is generated by a
barometric condenser. They frequently operate at 0.13 to 0.07 atm (660
mm - 710 mm or 26 - 28" Hg of vacuum).
26
-------
104 GLYCERINE RECOVERY
1041 RECEIVING
STORAGE-TRANSFER
1042 LYE TREATMENT
1043 GLYCERINE EVAPORATION
1044 GLYCERINE STILL
SWEET WATERS v
AND LYES
ALUM _
HCL ^^^"^
V^_
—*•
_
MIXER
1
FILTER PRESS
M
* I
J
I
I
TREATED
.GLYCERINE
LIQUOR
RECYCLE
"*• EVAPO
A
\
SALT
BAROMETRIC
' CONDENSER
1
RATHR >
f
1
1
1
1
Ls
•*
SEPARATOR r'
i I
1 1
1 i
I ,
STEAM
CRUDE
GLYCERINE
SALT RECYCLE
•- TO SOAP
MANUFACTURE
BAROMETRIC
CONDENSER
1
1
STILL '
CHARCOAL L
-•- FIITFR J
1 1
1 1
" 1
1 1
i I 1 1
__ STEAM
RE-
FINED
GLYCEF
INE
SOLID WASTE
104209
SALT BRINE
104327
BAROMETRIC
CONDENSATE
104318
SOLID WASTE
704409
BAROMETRIC
CONDENSATE
104418
FIGURE
COOLING TOWER
SLOWDOWN
704404
-------
As the glycerine is concentrated the salt comes out of solution and is
removed from the evaporation kettle, filtered and returned to the soap
making process. In many plants this separating function is performed
continuously with a centrifuge with the filtrate being returned to the
evaporator.
The glycerine is usually concentrated to 80 percent by weight and then
either run to a still to be made into finished glycerine, or stored and
sold to glycerine refiners.
The sweet water glycerine from fat splitting is flashed to atmospheric
pressure, thereby releasing a considerable amount of water very quickly.
This can provide a glycerine stream of 20 percent glycerine or more
going to the evaporators. Since there is no salt used in fat splitting
there will be none in the sweet water.
The water from the barometric condenser used in concentrating will be
slightly rich in BOD5 due to the carryover of glycerine.
Distillation
The concentrated glycerine (80 percent)is run into a still which, under
reduced pressure, yields a finished product of 98* percent purity. Here
again a barometric condenser is used to create the partial vacuum.
At room temperature, the still bottoms (also called glycerine foots) are
a glassy dark brown amorphous solid rather rich in salt. Water is mixed
with the still bottoms and run into the waste water stream. This
particular stream is very rich in BOD5, and readily biodegradable. Many
alternative methods of disposal, including incineration, have been
evaluated, but the general practice is disposal in a waste water stream.
The other waste water stream, the barometric condenser water, will also
contribute to the total BOD5/COD load from the glycerine still.
Some glycerine refining is done by passing the dilute stream over ion
exchange resin beds, both cationic and anionic, and then evaporating it
to 98+ percent glycerine content as a bottoms product. This method is
suitable where there are copious quantities of water available and
energy costs are very high.
In the backwash of the ion exchange process the organic suspended solids
are stripped from the system. The regeneration cycle of both types of
beds will add a significant dissolved solids load to the waste water
system.
There are frequently three sets, in series, of both cation and anion
exchange resins used in this process. Each step is designed to reduce
the input load by 90 percent. Some of the fat splitting plants are
equipped with this type of unit.
SOAP FLAKES AND POWDERS (105)
28
-------
105 SOAP FLAKES AND POWDERS
1051 RECEIVING
STORAGE-TRANSFER
1052 FLAKING
CRUTCHING-DRYING
1053 SPRAY DRYING
1054 PACKAGING
NEAT SOAPS
BUILDERS
ADDITIVES
PACKAGING
EQUIPMENT
FILTER BACKWASH
105129
.FLAKES TO
PACKAGING
SCRUBBER
WASTEWATER
105201
WASTEWATER
705307
LEAKS, SPILLS, STORM
RUNOFFS, WASHOUTS.
705202
LEAKS, SPILLS, STORM
RUNOFFS, WASHOUTS.
705302
SCRUBBER
WASTEWATER
105401
SCRAP
TO SOAP
RECYCLE
PACKAGED
SOAP TO
WAREHOUSE
FIGURE
-------
Neat soap (65 - 70 percent hot soap solution) may or may not be blended
with other products before flaking or powdering. Neat soap is sometimes
filtered to remove gel particles and run into a crutcher for mixing with
builders.
After thorough mixing, the finished formulation is run into a f laker.
This unit normally consists of a two roll "mill" having two steel rolls.
The small upper one is steam-heated while the larger lower one is
chilled. The soap solidifies on the lower one and is sli-c into ribbons
as it sheets off the roller.
The ribbons are fed into a continuous oven heated by hot air. The
emerging flakes contain 1 percent moisture. As all of the evaporated
moisture goes to the atmosphere, there is no waste water effluent.
In spray drying, crutched, heated soap solution is sprayed into a spray
tower, or flash-dried by heating the soap solution under pressure and
releasing the steam in the spray dryer under reduced pressure. In
either case the final soap particle has a high ratio of surrace area to
unit of weight, which makes it readily dissolvable in water.
Some operations will include a scrap soap rebcil to recover reclaimed
soap. The soap reboil is salted out for soap recovery and tne salt
water is recycled. After frequent recycling the salt water becomes so
contaminated that it must be discharged to the sewer.
Occasional washdown of the crutcher may be needed. The tower is usually
cleaned down dry. There is also some gland water which Hows over the
pump shaft picking up any minor leaks. This will contribute a very
small, but finite, effluent loading.
The procedure for bar soap manufacture will vary significantly from
plant to plant, depending upon the particular clientele served. The
following description typifies bar soap manufacture.
In some processes additives are mixed with the neat soap in a crutcher
before any drying takes place. Another approach is to begin the drying
process with the hot neat soap going to an "atmospheric" flash dryer
followed by a vacuum drying operation in which the vacuum is drawn by a
barometric condenser. Soap is then double extruded into short ribbons
or curls and sent to plodders for further blending or physical
processing. At this point the soap will normally have 8 - 14 percent
moisture depending upon the previous course of processing.
i
Next, a milling operation affords the opportunity to blend in additives
as well as modify the physical properties of the soap. Tnis operation
has much more significance than just achieving uniformity in the mixing
of further added ingredients. The physical chemistry of soap is fairly
complex. Unless a bar of soap is almost predominately left in the Beta
phase, as distinct from the omega phase, longrange solubility, warping
resistance, and lathering properties are poor. Rapid chilling of the
30
-------
106 BAR SOAPS
1061 RECEIVING
STORAGE-TRANSFER
1062 CRUTCHING AND DRYING
EAT SOAP
DDITIVES-*-
1063 SOAP MILLING
1064 PACKAGING
FILTER
STRAINER
WATER
FILTER BACKWASH
1 06129
TO SOAP
MILLING
SCRUBBER
CONDENSER
WATER
WASTEWATER
106201
WASHOUTS
106202
WASTEWATER
106301
WASHOUTS
106402
SCRAP TO
-SOAP
RECYCLE
FINISHED SOAP
AND CAKES
TO WAREHOUSE
FIGURE 7
-------
soap puts it predominantly in Omega phase but successive milling steps
bring it back into Beta phase - hence the importance of milling.
The mill consists of two polished rolls rotating at different speeds tc
maximize the shearing forces. After milling, the soap is cut intc
ribbons and sent to the plodder.
The plodder operates much like a sausage grinder. It thus extrudes anc
cuts the soap into small chips, followed by further mixing in which ai:
of the individual pieces are melted together into an homogeneous mass.
The plodder is often operated under reduced air pressure so that any oc-
cluded air is removed in the blending process. It has a powerful screi
that forces the soap through minute holes in a perforated plate.
Plodding completed, the soap is extruded continuously in a cylindrica!
form, cut to size, molded into the desired form, and wrapped fo]
shipment. Most of the scrap in this operation is returned to thu
plodder.
At times there will be soap scrap which has become too dry to procesi
properly in the plodder and it must te returned to earlier steps in th<
soap making process.
The amount of water used in bar soap manufacture varies greatly. li
many cases the entire bar soap processing operation is done withou-
generating a single waste water stream. The equipment is all cleane'
dry, without any washups. In other cases, due to housekeeping
requirements associated with the particular bar soap process, there ar
one or more waste water streams from air scrubbers.
Since we are dealing with a consumer product with very distinct (an
important to the consumer) esthetic properties, all of these processe
can claim significance and essential character in the making of
particular bar.
Occupying a very minor position in the soap market, a bar made from col
frame soap may be found. After the saponif ication reaction, this soa
is poured directly from the reactor into molds. Upon cooling and th
completion of saponif ication, the molded soap is cut into bars. The e,
tire operation is carried out without the generation of any waste water.
SOAP ±1021
Neat soap (often the potassium soap of fatty acids) is blended in a
mixing tank with other ingredients such as alcohols or glycols tc
produce a finished product, or with pine oil and kerosene for a product
with greater solvency and versatility. The final blended product ma}
be, and often is, filtered to achieve a sparkling clarity before beinc
drummed.
In making liquid soap, water is used to wash out the filter press anc
other equipment. Waste water effluent is minimal.
32
-------
707 LIQUID SOAP PROCESSING
1071 RECEIVING
STORAGE-TRANSFER
7072 BLENDING
1073 PACKAGING
POTASSIUM SOAPS-
ADDITIVES-
SOLVENTS-
BLENDER
PACKAGING
EQUIPMENT
LIQUID SOAPS
TO WAREHOUSE
LEAKS, SPILLS, STORM
RUNOFFS, WASHOUTS.
707/02
WASHDOWNS;
HEELS. 707272
WASHOUTS
107302
FIGURE 8
LO
CO
-------
DETERGENT_PROCESS_DESCRIPTIONS
The first modern detergent introduced in the United States in 1933 was
an alkyl naphthalene sulfonate. The primary reason for the success of
detergents is their ability to overcome the hard water behavior of
soaps. Even though the detergents also react with hard water minerals,
the resulting compounds are themselves soluble, or remain colloidally
dispersed in the water system. There are four main groups of
detergents:
An ionics
Cationics
Amphoterics
Nonionics
Anionics comprise the most important group of detergents. They are
usually the sodium salts of an organic sulfate or sulfonate. Sulfates
are made from long chain "fatty alcohols" (of animal or petroleum
origin). Sulfonates generally are made from alkyl aryl precursors.
By 1957 synthetic detergents took over 70 percent of the market for
soap-like products in the United States.
Cationic detergents are known as "inverted soaps" because the long chain
ion is of the opposite charge to that of a true soap when dispersed in
wat Qr.
This class of detergents is made in quite small volumes. They are
relatively expensive and somewhat harsh on the skin. They make
excellent bacteriostats and fabric softeners and are used for this
purpose.
Nonionic detergents are an increasingly popular active ingredient of
automatic washing machine formulations. These products are unaffected
by hard water (they do not form ions) and are very low roamers (minimum
foam when agitated). They are made by the addition of fcthylene oxide to
an alcohol.
Amphoterics are those surface active agents which can eitner be anionic
or cationic, depending upon the pK cf the system wherein they work. An
important class chemically, they account for only a very small portion
of the detergent market.
DETERGENT MANUFACTURING PROCESSES
A finished, packaged detergent customarily consists of two main
components, the active ingredient (surfactant) and the builder. The
function of the surfactant is essentially that of wetting the substrate
to be cleaned. The builder performs many functions including buffering
the pH, soil dispersion, and soil anti-redeposition. Both classes of
materials are required fcr proper detergent performance.
34
-------
The processes described under this heading include the manufacture of
the surfactant as well as preparation of the finished detergent. The
number following the title of each process refers to the process flow
chart.
OLEUM SULFONATION/SULFATIQN j 2Q1L
One of the most important active ingredients of detergents is the
alcohol sulfate or alkyl benzene sulfonate - and particularly those
products made via the oleum route.
In most cases the sulf onation/sulf ation is carried out continuously in a
reactor where the oleum (a solution of sulfur trioxide in sulfuric acid)
is brought into intimate contact with the hydrocarbon or alcohol.
Reaction is rapid. The stream is then mixed, with water and sent to a
settler.
Prior to the addition of water the stream is an homogeneous liquid.
With the addition of water, two phases develop and separate. The dilute
sulfuric acid is drawn off and usually returned to an oleum manufacturer
for reprocessing up to the original strength. The sulf onated/sulfated
material is sent on to be neutralized with caustic.
This process is normally operated continuously and performs indefinitely
without need of periodic clean out. Pump glands occasionally leak.
Anticipating this problem, a stream of water is normally played over
pump shafts to pick up such a leak is it occurs, as well as to cool the
pump. The flow of waste water from this source is quite modest but
continual.
AIR-S03 §U L F AT I ON/ SULFONAT I ON_ H 02 1
This process for surfactant manufacture has numerous unique advantages
and is used extensively. In the oleum sulfation of alcohols, formation
of water stops the reaction short of completion because it reaches a
state of equilibrium, resulting in low yields.
With SO_3 sulfation, no water is generated, hydrolysis cannot occur and
the reaction proceeds in one direction only.
The absence of water in the S03 reaction is of a lesser importance in
sulfonation. What is particularly troublesome in the use of oleum for
alcohol sulfation is that water cannot be used for oleum separation due
to the potential hydrolysis that would take place. Even if this were
not a worry, no phase separation of the components takes place with the
addition of water to sulfated alcohols in oleum.
^ sulfonation/sulf ation is also quite amenable to batch processing and
in this manner can produce products having a minimum of sodium sulfate
(all of the excess of SO_3, or sulfuric acid in the case of oleum
sulfonation, will be converted into sodium sulfate in the neutralization
step with caustic) . Another advantage of the SO3 process is its ability
35
-------
u>
OLEUM SULFATION AND SULFONATION (BATCH AND CONTINUOUS)
20/7 RECEIVING
STORAGE-TRANSFER
2012 SULFONATION
2013 SPENT ACID
SEPARATION
WATER CAUSTIC
1 1
OLEUM
ALKYL BENZENE
A i r*ni ini ^
i
i
i
*
OLEUM
FUME
SCRUBBER
'
f
WASTE-
WATER
201101
-*
LEAKS, SPILLS, STORM
RUNOFFS, WASHOUTS.
207702
COOLING
WATER
-WATER
r~
«-..
t ^
«. RFAPTOR
4
f
* SCRUBBER
I
J
i ^
COOLING
WATER
207200
WASTE-
WATER
207207
WATER*
MIXER
1
1
1
1
1
i
LEAKS, SPILLS, STORM
• RUNOFFS, WASHOUTS.
207202
-
WASHOUTS
201302
SETTLER
i
SPENT ACID
207305
SULFONICACID
ANDSULFURIC
ACID ESTER TO
NEUTRALIZATION
FIGURE
-------
202 AIR-SO., SULFATION AND SULFONATION (BATCH AND CONTINUOUS)
2021 RECEIVING
STORAGE-TRANSFER
2022 SULFUR BURNING
2023 SULFONATION-SULFATION
SULFUR
SO3 LIQUID
ALKYL BENZENE.
ALCOHOLS
ETHOXYLATES
CONDENSATE
202106
LEAKS, SPILLS, STORM
RUNOFFS, WASHOUTS.
202102
SULFURIC ACID
202309
WATER
CAUSTIC
SULFONIC ACID AND
SULFURIC ACID ESTER
TO NEUTRALIZATION
AND SALES
VENT GASES
202308
WASTEWATER
202 301
WASHOUTS
202302
OJ
FIGURE 10
-------
to successively sulfate and sulfonate an alcohol and a hydro-carbon
respectively.
Care must be excercised in the SO3_ process to control reaction
conditions - particularly temperature - to minimize char formation and
possible sulfonation of the hydrocarbon chain of the alcohol.
Because of this reaction's particular tendency to char the product, the
reactor system must be cleaned thoroughly on a regular basis. In
addition there are usually several airborne sulfonic acid streams which
must be scrubbed, with the waste water going to the sewer during
sulfaticn.
SO3_ can be generated at the plant by burning sulfur or sulfur dioxide
with air instead of obtaining it as a liquid. See the accompanying flow
sheet for the process. For further technical information see Section X.
g03_SOLyENT_.AND_yACUyM_.SyLFONATION__(203)_
Undiluted SO3_ and organic reactart are fed into the vacuum reactor
through a mixing nozzle (vacuum maintained at 0.06 atm (5" Hg). Recycle
is accomplished by running the flashed product through a heat exchanger
back into the reactor. The main advantage of the system is that under
vacuum the SO3_ concentration and operating temperature is kept low,
thereby assuring high product quality. Offsetting this is the high
operating cost of maintaining the vacuum.
SyLFAMIC_ACID_SyLFATION__£20U)_
Sulfamic acid is a mild sulfating agent and is used only in very
specialized quality areas because of the high reagent price. The system
is of particular value in the sulfation of ethoxylates.
The small specialty manufacturer may use this route for making high
quality alcohol sulfates, equivalent to that from the chlorosulfonic
acid route, substituting hiah reagent cost for high capital costs of the
chlorosulfonic route.
CHLORDSULFONIC_ ACI D_SULFATION_±205]_
For products requiring high quality sulfates, chlorosulfonic acid is an
excellent agent. It is a mild sulfating agent, yields no water of
sulfation and aenerates pratically no side reactions. It is a corrosive
agent and generates HC1 as a by-product.
An excess of about 5 percent chlorosulfonic acid is often used. It will
yield an inorganic salt upon neutralization which is undesirable in some
applications as it can result in salt precipitation in liquid
formulations, -tc.
NEyTRALIZATigN_OF_SyLFURIC_ACIp_ESTERS
AND_SULFONIC_ACIDS_^20_6)_
38
-------
203 - S03 SOLVENT AND VACUUM SULFONATION
2031 RECEIVING
STORAGE -TRANSFER
2032 SULFONATION
2033 SULFONATION
ALKYL BENZENE
ALCOHOLS
ETHOXYLATES
SO.,
LIQUID
U)
^
LEAKS, SPILLS,
STORM RUNOFFS,
WASHOUTS
203102
REFRIGERATION
S02 T0
STORAGE
CONDENSATE
203206
CONDENSATE
203217
WASTEWATER
203301
WASHOUTS 203202
WASHOUTS 203302
WATER
CAUSTIC
, SULFONIC
ACID
FIGURE 11
-------
-C-
o
204 SULFAMIC ACID SULFATION
ALCOHOLS-
ETHOXYLATES
SULFAMIC ACID-
204? RECEIVING
STORAGE-TRANSFER
2042 SULFATION
LEAKS, SPILLS, STORM
RUNOFFS, WASHOUTS.
204102
SOLVENTS
WASTEWATER
204207
WASHOUTS
204202
WATER
CAUSTIC
AMMONIUM ALKYL
SULFATES
FIGURE 12
-------
205 CHLOROSULFONIC ACID SULFATION
2051 RECEIVING
STORAGE-TRANSFER
2052 SULFATION
CHLOROSULFONIC ACID
ALCOHOLS
ETHOXYLATES
LEAKS, SPILLS, STORM
RUNOFFS, WASHOUTS.
205/02
SCRUBBER
REACTOR
WASTEWATER
205201
WASHOUTS
205202
WATER
CAUSTIC
ALKYL SULFURIC ACID ESTER
TO NEUTRALIZATION
FIGURE 13
-------
206 NEUTRALIZATION OF SULFURIC ACID ESTERS AND SULFONIC ACIDS
206? RECEIVING
STORAGE-TRANSFER
2062 LIQUID NEUTRALIZATION
2063 DRY NEUTRALIZATION
ACIDS:
SULFURIC ACID ESTERS
SULFONIC ACIDS
BASES- •
OTHER INGREDIENTS:
WATER- SOLVENTS'
MYDROTROPES;
AUDI 1 Ivho
^_
^^
TO DRY NEUTRAL
\^^
' ^^^
TO DRY NEUTRAL
ik
^
^
**^
*" SCHUBBEH n^
1
1
1
k
NbUIHAL- /
IZATION f
REACTOR |
1
1
1
1 "
1 1
1
| WASTEWATER
• 206201
I
L_ WASHOUTS
* 206202
- WATER ACIDS
_ CAUSTIC
LIQUID PRODUCTS
AND SLURRIES TO
SALE, BLENDING,
OR CRUTCHING
BASES:
OTHER
INGREDIENTS:
DRY PRODUCTS
TO STORAGE
WASTEWATER
20630 J
WASHOUTS
206302
•WATER
FIGURE 14
-------
This step is essential in the manufacture of detergent active
ingredients; it converts the acidic hydrophylic portion of the molecule
to a neutral salt.
Alcohol sulfates are somewhat more difficult to neutralize than the
alkylbenzene sulfonic acids due to the sensitivity to hydrolysis of the
alcohol derivative. For this reason, neutralization is usually carried
out at a pH above 7 and as rapidly as possible.
This is not a difficult feat for those who neutralize continuously, but
it is more of a problem for the batch processor unless he has excellent
stirring.
As a result of hydrolysis occurring in the neutralization step, there
will be some free alcohol generated which would be picked up in the oil
and grease analysis. As a product this is riot all bad since the free
alcohol can actually be considered a foam stabilizer in some situations.
If used in heavy duty products, the alcohol tends to be lost in the
spray tower.
S PR A Y_ PR I ED_ PET ERGENT S _J 2 0 T_\_
This is another critical area of detergent manufacture. In this segment
of processing, the neutralized sulfonates and/or sulfates are brought to
the crutcher where they are blended with requisite builders and
additives. From here the slurry is pumped to the top of a spray tower
of about U.5 - 6.1 m (15 - 20ft) in diameter by 45 - 61m (150 - 200 ft)
ligh where nozzles, around the top, spray out detergent slurry of
approximately 70 percent concentration.
A large volume of hot air enters the bottom of the tower rising to meet
the falling detergent. For low density products, hot gas and powder
flow concurrently downward.
This step is critical in that the detergent particles' shape, size and
density are determined by all of the design preparation made previously,
and the shape and size in turn will largely determine dusting and the
solubility rate of the detergent itself in the washing process.
The air coming from the tower will be carrying dust particles which must
De essentially eliminated to meet air quality standards.
Due to product change and buildup of combustible deposits, the spray
:owers are periodically shut down and cleaned. This practice varies
:rom two or three times a week to once in two weeks or longer. One
:hing that all tower operations share is the cleaning process. First,
-he easily available material sticking to the tower walls is scraped to
3e recycled if at all possible, or sent to solid waste.
are sent into the tower with abrading equipment to continue the dry
cleaning process. Here again, the product is usually preserved for
reuse or disposed of as a solid waste.
43
-------
207SPRAY DRIED DETERGENTS
207? RECEIVING
STORAGE-TRANSFER
ACTIVES-
LAS SLURRY, ALCOHOL
SULFATE SLURRY;
ETHOXYLATES
BUILDERS
PHOSPHATES. SILICATES;
CARBONATES, SULFATES;
BORATES
ADDITIVES:
AMIDES; SOAPS; FLOUR
ESCENT WHITENERS;
PERFUMES, DYES; PER-
BORATE; CMC; ANTICAKING
AGENTS; ENZYMES
2072 CRUTCHING
2073 SPRAY DRYING
2074 BLENDING AND PACKAGING
WATER
FINISHED
DETERGENTS
TO WAREHOUSE
DUST SCRUBBER
HIGH-
PRESSURE
PUMP
ADDITIVES
WATER
ADDITIVES,
BUILDERS,
AND ACTIVES
FROM
STORAGE
WASH DOWN
WATER
PACKAGING
EQUIPMENT
TOCRUTCHER
BLENDER AND
PACKAGING
SCRAP TO RECYCLE
OR SOLID WASTE
207416
WASHDOWN WATER
TO WASTE OR
RECYCLE TO
CRUTCHER
207312
-------
Finally, the tower is thoroughly washed down by spraying streams all
over the inside surface. The final step is mandatory since the
detergent manufacturers must be very careful to avoid any mixing of any
phosphate-nonphosphate formulations, white with colored systems or
anionic with nonionic formulations.
The mixing problem is compounded somewhat by the fact that some
detergent manufacturers custom process for a variety of marketers which
requires more frequent spray tower "turnaround".
Waste water streams are rather numerous (see accompanying flow sheet for
process). They include many washouts of equipment from the crutchers to
the spray tower itself. One waste water flow which has high loadings is
that of the air scrubber which cleans and cools the hot gases exiting
from this tower. This is only one of the several units in series
utilized to minimize the particulate matter being sent into the
atmosphere.
All of the plants recycle some of the waste water generated. Some of
the plants recycle all of the flows generated.
Due to increasingly stringent air quality requirements, we can expect
that fewer plants will be able to maintain a complete recycle system of
all water flows in the spray tower area. In the case of the fast
"turnaround" tower, they, too, are unable to utilize all of their
scrubber and other wash waters.
After the powder comes from the spray tower it is further blended and
then packaged. Solid wastes from this area are usually recycled.
LIQUID DETERGENTS J2081
Sulfonated and sulfated products as produced in processes described in
201 - 206 are pumped into mixing tanks where they are blended with
numerous ingredients, ranging from perfumes to dyes. From here, the
fully formulated liquid detergent is run down to the filling line.
The filling line usually consists of a long conveyor which passes many
stations. Each station performs a given task, such as filling, capping,
checking weight, labeling, etc. Often, soap solutions are used to
lubricate the conveyor so that the bottles flow smoothly past the vari-
ous stations.
Whenever the filling line is to change to a different product, the
filling system must be thoroughly cleaned out. This is equally true of
the mixing equipment. Properties of differing products are often so
contrasting that there must be no cross contamination, otherwise the
performance and other specifications cannot be met. To avoid this
problem the mixing equipment and all filling plumbing is thoroughly
flushed with water until it runs clear.
DRY_DETERGENT BLENDING {209^
45
-------
LIQUID DETERGENT MANUFACTURE
2081 RECEIVING
STORAGE-TRANSFER
2082 BLENDING
2083 PACKAGING
,CTIVES:
LAS; SULFONIC ACID;
ETHER SULFATES;
OLEFINSULFONATES;
ETHER SULFONATES;
AMINE OXIDES; AMIDES
tUILDERS:
PHOSPHATES; SILICATES
ADDITIVES:
HYDROTROPES;
SOLVENTS; COLOR;
PERFUME
WATER.
MIXERS
WATER
TREATMENT
BULK
DETERGENT
SALES
WASH DOWN
208212
PACKAGING
EQUIPMENT
CASE GOODS
"TO WAREHOUSE
CONTAINER
WASHINGS
208310
SOLID WASTE
208309
WASHOUTS
LEAKS, SPILLS,
WASHOUTS
-------
209 DETERGENT MANUFACTURE BY DRY BLENDING
209? RECEIVING
STORAGE-TRANSFER
2092 DRY BLENDING
2093 PACKAGING
ACTIVES:
LAS SLURRY; FLAKES;
BEADS; SULFONIC ACID;
AMIDES; ETHOXYLATES
BUILDERS:
SILICATES; CARBONATES
PHOSPHATES; BORATES
ADDITIVES:
CMC; ANTICAKING AGENTS;
COLORS; PERFUMES; _
ABRASIVES; DIATOMACEOUS
EARTH; PUMICE
BULK
DETERGENT
SALES
PACKAGING
EQUIPMENT
SOLID WASTE
2O9209
u
WASHOUTS
209202
CASE GOODS
TO WAREHOUSE
SOLID WASTE
209309
L.
WASHOUTS
209302
FIGURE 17
-------
Fully dried "active" (surfactant) materials are blended with additives,
including builders, in dry mixers. In the more sophisticated plants
mixing time is utilized to the maximum by metering components into
weighing bins prior to loading into mixers. When properly mixed, the
homogeneous dry product is packed for shipment.
Normal operation will see many succeeding batches of detergent mixed in
the same equipment without anything but dry cleaning. This procedure is
followed until the next formulation to be blended must not be
contaminated with even an almost negligible amount of the previously
prepared product. At this time the equipment must be completely washed
down.
For this reason, a modest amount of waste water is required for the
blender to maintain specification requirements.
The products fulfill a wide variety of industrial cleaning uses from
dairy cleaning to box car washing. They are also used to some extent in
household products.
DRUM^DRIED, DETERGENTS__(2.10 }_
Drum drying of detergents is an old process. Much of the equipment
still in use is well over thirty years old. The process yields a fairly
friable product which can become quite dusty with any extensive
handling.
There are several types of drum driers; those which have double rotating
heated drums with liquid feed coining onto the space above and between
the rolls, and a twin-drum dryer with dip or flash faed. The dip feed
is a pan in which the "bottom" of the roll or drum picks up material to
be dried.
The thin layer is removed continuously by a knife blade onto conveyors.
The powder is substantially anhydrous. The vapors coming off are often
collected and removed through a vapor head between the drums.
The rolls of a drum dryer are often 0.6- 1.8m(2-6 ft) in diameter
and 0.9 - 4.5 m (3 - 15 ft) long with revolution speeds of 5 - 10 rpm.
About 6-15 seconds residence time is provided the slurry on hot metal
surface which is short enough to avoid degradation of heat-sensitive
products.
As an example of the limitations of drying capacity, the capacity of the
drum varies between 4.5 and 48.8 kg of finished product per sq meter of
drying surface per hour (between 1 and 10 Ib per sq ft per hour).
This operation should be essentially free of generation of waste water
discharge other than an occasional washdown.
DETERGENT_BARS_AND_CAKES_J[21.1.1
48
-------
210 DRUM DRIED DETERGENT
2101 RECEIVING
STORAGE-TRANSFER
2102 DRUM DRYING
2103 PACKAGING
ACTIVES
BUILDERS
ADDITIVES
r
SCRUBBER 1^-,
CRUTCHER
I
'
I
I
1
1
1
,J
v*-
'l
1
I
I
J
DRUM
DRIER
»
STOR-
AGE
1 — 1
i
BULK
DETERGENT
SALES
WASTEWATER
210201
WASHOUTS
2/0202
PACKAGING
EQUIPMENT
WASHOUTS
210302
PACKAGED
•*- GOODS TO
WAREHOUSE
FIGURE 18
-------
Ul
o
27 7 DETERGENT BARS AND CAKES
2111 RECEIVING 2112 MIXING
STORAGE-TRANSFER WORKING-CONDITIONING
2113 STAMPING-PACKAGING
BUILDERS
ADDITIVES
KtUltlM 1 b —
" ~~)
MIXER
— »•
f
SCRUBBER
PLODDER
TABLET
MACHINE
k
P
1
1
k
-7-
[
1
— WATER
BAR
CUTTER
PACKAGINC
•*
^
STAMPER
WRAPPER
PACKAGER
-*-
BAR
DETERGENTS
TO
WAREHOUSE
DETERGENT
CAKES
I I
SOLID WASTE
2?7202
WASTEWATER
211201
WASHOUTS
211302
SCRAP SOAP
TO RECYCLE
WASHOUTS
211202
-------
In answer to the need for a "bar soap" which performs satisfactorily in
hard water, the detergent industry manufactures and markets detergent
bars. They constitute about 20 percent of the toilet bar market.
There are two types of "detergent" bars, those made of 100 percent
synthetic surfactant and those blending synthetic surfactant with soap.
Once the active ingredients have been manufactured they are blended in
essentially the same manner and in similar type of equipment used for
conventional soap.
Due to the sensitive nature of the surfactant portion of the detergent
bar, fairly frequent cleanups, including equipment washdowns are
required. Otherwise thermally degraded surfactant will contaminate the
bar leading to such undesirable properties as stickiness and off-color.
FORMULATIONS
Soaps, detergents, and cleaning agents - some of the latter containing
specific ingredients for specified cleaning purposes - contain a wide
variety of chemical compounds to carry out the functions of the cleaning
process involved. In the case of soap, the sodium or potassium salts of
a range of fatty acids, having carbon numbers of 8 to 22, constitute the
principal surfactant or cleansing agent. in addition, there is a
certain amount of salt, NaCl, included in soap to perform the function
of having an electrolyte present, which increases diffusion and surface
orientation, by ion reactions. Glycerine, itself, is often left in the
soap, or purposely added, for its general effect in promoting a feeling
of softness and slipperiness, the latter feature being one that leads
the user to thoroughly wash off soap residue, especially in personal
use.
In the case of a typical all-purpose household detergent, a general
average of approximately ten chemical components are included in a
typical formulation. All these compounds have definite functions to
produce a balanced detergent. The principal component, of course, is
the surfactant itself, typically, an alkyl-aryl sulfonate; a sulfate
salt of lauryl alcohol; and various types of sulfates or sulfonates
derived from ethoxylated alcohol or cf other aromatic compound sul-
fonates. The surfactant itself is largely effective in reducing
interfacial tension between the surface to be cleansed and the soil
deposit itself. Typically, detergents contain approximately 5-30
percent of such surfactant active-ingredient material.
An important ingredient in detergents, at least up to the present, is
the radical phosphate, PO4, which is included in a variety of forms,
discussed later. The function of the phosphate is that of a ctisperser,
a suspender, an emulsifier, and a buffer to reduce the general
alkalinity of the surfactants and produce a detergent in the pH range of
7.0 - 9.0. The phosphate ion has been an important multiple functioning
ingredient in detergents. If it is reduced by laws, these functions of
a detergent will have to be handled by other compounds that then need to
51
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be included in a formulation. Another major constituent of most
detergents is an inorganic salt. Most typically, these are either in
the form of sodium sulfate and, occasionally, sodium chloride or other
added inorganic salts. In detergents they serve the purpose of
diminishing the interfacial tension, particularly that between water,
carrying the detergent, and the soil deposition to be removed. They
also act for this reason as a disperser of the soiling. Additionally,
an important function is to provide an electrolyte; i.e., an ion content
which enhances and accelerates the interchange and surface orientation
of wetting and organic solubilizing portions of a molecule. These
inorganics are usually present up to about 20 percent in the typical
formulated detergent.
Methyl cellulose, in amounts of about 1 percent, are present in many
detergent formulations to reduce redeposition of the soiling, once it
has been removed from the soiled surface. Silica, in various forms, but
usually in the form of sodium silicate, to an extent of 5 percent or
less, is included in many formulations to minimize the corrosion of
metals, particularly those present in a drum liner or other washing con-
tainer surfaces. Fatty acids, such as are used in the soap
manufacturing process by neutralization, are added up to a range of
about 3 percent, largely to enhance foam stability and, therefore, to
prevent an over-use of the detergent in the washing solution. The
borates are also generally added, often in the form of sodium perborate.
These borate compounds are added up to an extent of 10 percent, and
serve the purpose of bleaching a fabric and/or removing stain deposits
of soiling on textile surfaces. In addition to these components there
are often perfumes added, as well as anti-oxidants. Dyes are often
added as brighteners, even fluorescent dyes, so that the reflectivity of
the surface is enhanced, making it look brighter. Obviously, the
perfumes are to give a more pleasing cdcr and aroma. The anti-oxidants
are added, particularly when there are fatty acids in the composition,
to avoid a noticeably rancid odor.
In general, cleaning compounds contain far more of the inorganic salt
compounds, which are more efficacious in cleaning duties against
surfaces such as dishware, flooring, and in the cleaning of machine
parts, after oil has been used during lathing operations. Thus, a
typical floor cleaning formulation contains as much as 60 percent of
sodium silicate, as much as 10 percent of phosphates, in the form of
tri-polyphosphate, also, occasionally the tetravalent potassium pyro-
phosphate. The surfactant in such cases is usually an alkyl-aryl
sulfonate to make up the balance of the composition. Hand dishwashing
detergents contain active ingredients such as amine oxides and sulfated
ethoxylated lauryl alcohols. The industrial machine dishwasher products
are compounded as high as 50 percent by weight sodium tri-polyphosphate,
another 25 - 50 percent sodium metasilicate (anhydrous) and a minor
amount 2-5 percent organic surfactant.
Sodium carbonate, present either as the normal divalent carbonate, or as
the sesqui-carbonate, in amounts ranging up to 10 percent, is commonly
used. Again, a tri-polyphosphate is included to the extent of 40
percent or up to the balance of the detergent, if it is a powder.
52
-------
Of all the functions, mentioned earlier with respect to the compound,
illustrating the functions, the main purpose of a soap, detergent or
cleaning agent must be to loosen occluded soils and to suspend it so
that it does not redeposit. Accordingly, the basic principle of the
surfactant, even as soap itself, is the lowering of the interfacial
tension between the systems consisting of the fabric or surface to be
cleaned and the soiling on that surface. Frequently the surfactant
function is accomplished by components which also reduce the interfacial
tension between the water in the system, and the air. This leads to
high foaming compositions which are not useful in actually cleaning and
removing the soiling depositions.
In the case of soap, now used mostly for personal body care, the main
function is that of interfacial separation, from the epithelial or skin
surface and the soiling, which can be produced by the body itself, as
well as from extraneous particulate matter, oils and greases. The main
components of the body's own soiling are those of the fatty acid-esters
which range in composition from carbon numbers C5 up to C37. The
compounds of lower molecular weight are generally the fatty acid salts
themselves or the fatty acid esters of these salts. The other main soil
components are the usual sebaceous gland exudate, consisting largely of
the esters of glycerine.
These glyceryl esters are not unlike those found in fats itself;
however, they range in chemical structure and composition to a far
greater extent than in the soap fatty acids. Another component of
sebaceous soiling is the androstanyl-sterols and squalenes. These have
molecular weights as high as C37 and range down to those in the order of
C19. These esters are particularly difficult to remove, as the sebum is
itself a very complex physical-chemical inter-diffused solid and semi-
solid solution.
Surface tension reducing agents, such as inorganic salts, are not very
useful in the cleansing problem requiring the use of a soap. Again,
they serve mostly the function of decreasing interfacial tension between
air and water; and roughly for each per cent of content in the cleansing
solution they reduce the surface tension by approximately 2 dynes per
centimeter. Their equivalency can be obtained readily, without the
foaming disadvantage, simply by raising the temperature of cleaning
about 10 C (50 F) which gives the equivalent net effect.
As mentioned, there are a variety of inorganic salt compounds which are
found in detergents and serve to perform the functions first
illustrated. While normally, in soap, sodium chloride is the usual
electrolyte, the compounded detergents have a far broader range of
'inorganic compounds to serve functions illustrated earlier. In addition
to the usual salts of sulfuric acid, usually present as the sodium
sulfate, there are a variety of carbonates, silicates, phosphates and
borates.
53
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SECTION IV
INDUSTRY CATEGORIZATION
Introduction
There are several ways in which the soap and detergent industry could be
categorized. While each may have its own special rationale, the search
was for the system of categorization that would best identify potential
waste water sources and controls, provide a permit granting authority
with a way to analyze a specific plant regardless of its complexity, and
permit monitoring for compliance without undue complication or expense.
The systems examined included categorization by raw materials used,
wastes discharged, finished products manufactured, processes employed,
and plant size or age.
Systems based solely on raw materials used, wastes discharged, or
finished products manufactured are either overly complex, even if based
on generic chemical groups, or highly arbitrary if greatly simplified.
This is true in respect to both categorization and monitoring for
compliance. Furthermore, they take into consideration only the
potentials for waste generation that are inherent in the nature of the
materials (e.g., boiling point, solubility, etc.) and ignore the
potentials of other factors such as processes employed.
The operations of the soap and detergent industry may be considered to
consist of application of processes to raw materials for production of
intermediates, which in turn are subjected to further processing to
arrive at the finished or marketed products. There is an intimate
relationship within chains of raw materials, intermediates, processes
and finished products with the processes employed being the key to
obtaining the finished products from the raw materials. Thus, a system
of categorization based on processes reflects all variables that affect
raw waste discharges.
Plants employing specific sets of processes tend to be of the same
general age and the principal effect of age is reflected in the
processes utilized (e.g., kettle boiling of fats versus continuous
neutralization of fatty acids for production of neat soap), not in the
level of raw waste load generated by a particular set of processes.
Moreover, the determination of age is complicated by extensive repair
and replacement of process units. For example, what is the age of a
large kettle boiling facility originally constructed 50 years ago, but
in which an average of one kettle has been reconstructed every two years
for the past thirty years? What is the age of a spray drying tower
constructed in 1930 for manufacturing soap granules, modified in 1946
for production of spray dried detergents, and subjected to periodic
replacement of working parts since modification? In view of the
foregoing, age of plants is not considered to be a practical basis for
categorization.
Plant size as a basis for categorization is even more complex than
evaluation of age. Some independents have relatively small plants that
55
-------
in complexity of processes employed equal the largest plants of the
major international companies. A relatively small operation consisting
of a single process chain (e.g., production of bar soaps utilizing fatty
acid neutralization) may equal in size the comparable segment of the
largest complex plant. Size of plant may be the result of difference in
the physical size of individual units of equipment or the number of
units of the same physical size. Thus, categorization based on size
would result in an unmanageable welter of categories, with many
representing only one or a very few plants.
Though plant size cannot be used as a basis for orderly categorization,
and thus is not reflected in the proposed guidelines and standards,
there are factors generally associated with size that should be
considered. The complexity of a plant (i.e. , number of processes and
products) is frequently associated with size, the small plants tending
to be more limited in diversity. This may curtail the ability of a
small plant to work off a by-product or waste as a feed material for
other processes. Similarly, the limited volume of a waste produced in a
small plant may prohibit installation of by-product utilization
processes (e.g., use of nigre from kettle boiling for manufacture of pet
soaps and soap-based lubricants) on a scale that is economically viable.
Categorization
The categorization consists of two major categories and 19
subcategories. The major categories follow the natural division of soap
manufacturing (production of alkaline metal salts of fatty acids derived
from natural fats and oils) and detergent manufacturing (production of
sulfated and sulfonated cleaning agents from manufactured raw materials,
primarily petroleum derivatives). The subcategories are based on
discrete manufacturing units employed by the industry for conversion of
raw materials to intermediated products and conversion of intermediate
products to finished/marketed products. A manufacturing unit may
contain a single process (e.g., continuous neutralization for production
of neat soap by fatty acid neutralization) or a number of processes
(e.g., crutching, drying, milling, plodding, stamping and packaging for
production of bar soaps from neat soap).
Several advantages result from the categorization. It accounts for the
variable effects on raw waste loads attributable to raw materials,
processes and finished product. The potential sources and natures of
waste waters are readily discernible, as are the potential in-plant
control measures. It is amenable to use in development of permits
irrespective of the complexity of a plant.
The subcategories are as follows:
SOAP MANUFACTURE
Soap Manufacture by Batch Kettle (101)*
Fatty Acid Manufacture by Fat Splitting (102)
Soap Manufacture by Fatty Acid Neutralization (103)
Glycerine Concentration (104A)
56
-------
Glycerine Distillation (104B)
Soap Flakes and Powders (105)
Bar Soaps (106)
Liquid Soap (107)
DETERGENT MANUFACTURE
Oleum Sulfonation and Sulfation (Batch and Continuous) (201)
Air-S03_ Sulfation and Sulfonation (Batch and Continuous) (202)
SO3 Solvent and Vacuum Sulfonation (203)
Sulfamic Acid Sulfation (20«)
Chlorosulfonic Acid Sulfation (205)
Neutralization of Sulfuric Acid Esters and Sulfonic Acids (206)
Spray Dried Detergent (207)
Liquid Detergent Manufacture (208)
Detergent Manufacturing by Dry Blending (209)
Drum Dried Detergents (210)
Detergent Bars and Cakes (211)
*The numbers shown after the subcategories are used throughout the
report to identify the subcategories/processes.
57
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SECTION V
WASTE CHARACTERIZATION
INTFODUCTION
Numerous organic and inorganic chemical compounds are used in the
manufacture of soaps and detergents. As the reactions are carried out
some of these materials and their derivatives enter the waste waters
from the processing steps. These materials are then treated as
contaminants and processed as waste water in conventional waste
treatment units. In discussion of the individual unit processes that
follow, the sources and nature cf waste waters are presented in some
detail. The numbers associated with the processes and waste streams are
keyed to the process flow sheets, Figures 1 through 19.
SQAP_MANUFACTURE BY BATCH KETTLE -- (PROCESS 101)
Introduction
Effluents of this process arise from three sources. Handling of fats
and oils results in leaks and spills (streams 101102 and 101202). These
are usually collected with water and the fats skimmed. Pretreatment of
the fats or oils results in process waste waters 101321 and 101218.
Soap making results in two by-products, 101319 and 101320, which gene-
rally are disposed of as waste waters. These streams are discussed in
detail in the following sections.
Water^and_Waste_Water_Balance
Water for this process will usually come from municipal systems since
the plants are old and somewhat isolated. For the barometric condenser
(101218) surface water or cooling tower water will be used. Since steam
is used for heating the fat in both pretreatment and saponification,
some process water is introduced in this manner.
Kettle boiling soap is a batch process and water use will be
intermittent. Instantaneous flows of 0.12-18.9 I/sec (2-300gpm) will be
experienced. Overall water use can be limited to 623 1/kkg (75 gal/1000
Ib) of soap, but as much as 2080 1/kkg (250 gal/1000 Ib) is used.
Water reuse and recycle is not common in kettle boil soap plants for
process water. Where a barometric condenser is used for the steaming
pretreatment step, recycle through a cooling tower is sometimes used,
but even here use of surface water is more common. Except for the
barometric condenser, all water use can be considered process water.
Specific waste water sources and constituents are discussed generally
and specifically tabulated in the next section.
59
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Waste^Water_Constituents
Leaks, spills and storm runoff or floor washing (streams 101102 and
101202) are invariably collected for recovery of fats and oils by
settling and skimming in fat traps. The waste water will contain some
emulsified fats, since the skimmers and settlers do not operate at 100
percent efficiency.
The fat pretreatment is carried out to remove impurities which would
cause color and odor in the finished soap. Acid and/or caustic washing
may be used. This results in sodium soaps or sulfuric acid solutions of
fatty acids (101231). Other pretreatment steps make use of proprietary
chemical formulas which result in water containing the treatment
chemicals, fatty impurities and emulsified fats. Clay and carbon
treatments give solid wastes and do not directly result in aqueous
effluents, but steam is used for heating and the condensate must be
removed. Often a barometric condenser is used, and there is carryover
of low molecular weight fatty acids (101218).
Waste waters from the fat skimmer and from the pretreatment steps each
contribute about 1.5 kg of BOD5 per 1000 kg of soap (1.5 lb/1000 Ib).
Concentrations typically are 3600 mg/1 EOD5, 4267 mg/1 COD, 250 mg/1 of
oil and grease with a pH of 5.
Saponification of the fats and oils by sodium hydroxide and salting out
of the soaps (graining) with salt does not necessarily lead to any
effluent. The nigre which comes from washing excess salt and impurities
from the neat soap with aqueous caustic is always recycled to some
extent. The organic portion consists of low grade soap. In some
plants, the nigre is acidified to convert the soaps to fatty acids which
are recovered for sale. Although acidification removes much of the
organic contaminant, some is still discharged (101320). Some manu-
facturers' third alternative for the nigre is the sewer (101319).
The stream referred to as sewer lyes (101319) arises most often from the
reclaiming of scrap soap. The lye and salt water added to separate the
soap must be discarded because it contains paper and other dirt.
sewer lyes and nigre are concentrated waste waters (in mg/1) alkalinity
up to 32,000, BOD5 as high as 45,000, COD up to 64,000, chlorides of
47,000 and a pH of 13.5. Volumes, however, are small - 249 1/kkg of
soap (30 gal./1000 Ib) .
FATTY ACIDS BY FAT SPLITTING -- (PROCESS 102)
Introduction
In this process, fats and oils are converted to fatty acids and
glycerine by hydrolysis with water. In Section 103 conversion of fatty
acids to soap is considered and Section 104 deals with glycerine
recovery. There are two process condensates which contain organic
contaminants - (102322 and 102418). Also, treatment of the fatty acid
60
-------
still bottoms results in contaminated water (102423). Since streams
from fat pretreatment (102221) and leaks and spills are essentially the
same as analogous streams (101102 and 101202) in Process 101, the
discussion will not be repeated.
Fatty acids from the fat splitting frequently are given a light
hydrogenation (usually employing a nickel catalyst) to eliminate
polyunsaturation in the acids. The only waste water coming from this
step is that arising from equipment cleanouts.
Water and Waste Water Balance
In general fatty acid plants are relatively new and contain a water
recycle system. The small amount of clean water required will come from
surface water, municipal systems, or wells. Although operation of
surface condensers and barometric condensers requires thousands of gal-
lons per minute, blowdown from fatty acid plants ranges from 3.2-12.6
I/sec (50-200gpm).
The other main contaminated stream is from treating still bottoms
(102423). It is smaller, but highly contaminated.
Cleanouts of hydrogenation equipment are infrequent and the total volume
of water is small. Potable water is used to preserve cleanliness.
Wagte_Water_Constituents
See Process Section 101 for discussion of 102102, 102202, and 102402
which are waste waters from leaks, spills and storm runoff. Also, fat
pretreatment wastes 102205 and 102224 are covered under Process 101 for
the analogous streams.
Process condensate 102322 from fat splitting will be contaminated with
volatile low molecular weight fatty acids as well as entrained fatty
acids and glycerine streams. The barometric condensate 102418 will also
contain volatile fatty acids. These streams will be settled and skimmed
to remove the insoluble fatty acids which are processed for sale. The
water will typically circulate through a cooling tower and be reused.
To keep emulsified and soluble fatty material at a reasonable level,
part of the stream is purged to the sewer. This blowdown (102204,
102304, 102404) contributes about 10 kg of BOD5 and 18 kg of COD per kkg
(10 Ib BOD5 and 18 Ib COD/1000 Ib) of fatty acids produced plus some oil
and grease.
Treatment of stream 102423 consists of acidification to break the
emulsion and skimming of insoluble fatty acid pitch. The waste water is
neutralized and sent to the sewer. This waste water will contain salt
from the neutralization, zinc and alkaline earth metal salts from the
fat splitting catalyst and emulsified fatty acids and fatty acid
polymers. One plant had about 0.6 kg of BOD5 and 0.9 kg of COD/kkg (0.6
Ib BOD5 and 0.9 Ib COD/1000 Ib) of fatty acids from this source.
61
-------
Fatty acids and a modest amount of nickel soaps constitute the bulk of
contaminants from hydrogenation. Very small amounts of suspended nickel
may be present.
SOAP BY FATTY ACID NEUTRALIZATION — (PROCESS J031
Introduction
This process is relatively simple and high purity raw materials are
converted to soap with essentially no by-products. Leaks, spills, storm
runoff and washouts are absent. There is only one waste water of
consequence. It is 103326, the sewer lyes from reclaiming of scrap.
Stream 103224 is generally nonexistent since there is a net consumption
of brine in the process.
Water_and Waste Water Balance
Except for the small amount of water (258 1/kkg; 31 gal/1000 Ib of soap)
used for reclaiming scrap and resulting in the sewer lyes, the process
produces no other aqueous effluent. Potable water is fed into the
process.
Waste Water Constituents
The sewer lyes (103326) will contain the excess caustic soda and the
salt added to grain out the soap. Also, they will contain some dirt and
paper not removed by the strainer. Typically 3 kg of BOD5 and 5.5 kg of
COD/1000 kg (3 Ib of BOD5 and 5.5 Ib of COD/1000 Ib) of soap will be
discharged.
GLYCERINE RECOVERY — (PROCESS 104)
Introduction
The feedstock for this unit process comes from soap boiling and fat
splitting processes 101 and 102. Both crude glycerines will contain
about 90 percent water, but that from soap kettle boiling will contain a
fair amount of salt and some NaOH. Both streams will contain soap or
fatty acids which must be removed in the pretreatment section by
precipitation with alum and filtration.
There are three waste waters of consequence from this process; two
barometric condensates, from evaporation of water (104318) and from
distillation of glycerine (104418), plus the glycerine foots or still
bottoms (104428). Contaminant of the barometric condensates is
essentially glycerine with a little entrained salt. The glycerine foots
are water soluble and are removed by dissolving in water.
Glycerine can also be purified by use of ion exchange resins to remove
the sodium chloride followed by evaporation of the water. This process
62
-------
puts additional salts into the waste water but results in less organic
contamination.
_and Waste Water Balance
Compared with the amount of water used in the barometric condensers,
water used for other purposes is negligible.
Installations not recirculating cooling water through a cooling tower
use from 698,000-1,540,000 1 of water per kkg (84,000-185,000 gal. of
water per 1000 Ib) of glycerine produced. With a cooling tower,
blowdown consumes 9975 1/kkg (1200 gal./1000 Ib) glycerine.
The ion exchange process is reported to use 449 1/kkg (54 gal/1000 Ib)
of glycerine for both backwashing and regeneration.
The source of water for glycerine recovery is usually surface water.
Since it is used mainly for condensing steam, quality is unimportant.
Typically, a plant will withdraw water from a river, put it through the
barometric condensers, and discharge it into the river with no
treatment.
As mentioned above, water used for washout of the still, for steam
generation and the ion exchange process is relatively small. These
water uses require treated water, usually from municipal supplies. No
water is produced or consumed in the process.
Waste^Water_CQnstituent s
The two barometric condensers streams (104318 and 104418) become
contaminated with glycerine and salt due to entrainment. Stream 104428
is a water soluble by-product which is disposed of by washing into the
sewer. It contains glycerine, glycerine polymers, and salt. The
organics will contribute to BOD5, COD and dissolved solids. The sodium
chloride will also contribute to dissolved solids. Little or no
suspended solids, oil and grease or pH effect should be seen.
From the glycerine evaporator barometric condenser about 30 kg of COD
and 15 kg of BOD5 per kkg (30 Ib of COD and 15 Ib of BOD5 per 1000 Ib)
of product will be discharged. The foots and glycerine still contribute
about equal amounts of BOD5 and COD, 2.5 kg (2.5 Ib) and 5 kg (5 Ib)
respectively per kkg (1000 Ib) of glycerine produced. Because the
barometric condensers use large amounts of water, concentrations are
low. The foots are diluted only enough to remove them from the still,
and concentrations of organics and salts are about 30,000-400,000 mg/1.
SOAP FLAKES AND POWDERS— (PROCESS 105)
Introduction
In this process the neat soaps from processes 101 or 103 are converted
to flakes or powders for packaging and sale. The unit processes produce
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the dry soap in the physical form desired. There are a number of
possible effluents shown on the flow sheet for process 105. However,
survey of the industry showed that most operating plants either recycled
any waste water to extinction, or used dry cleanup processes.
Occasionally water will be used for equipment cleanup.
In converting neat soap to flakes, pcwder or bars, some scrap results.
The flow sheets show scrap reclaim in processes 101 and 103. There is
an aqueous effluent - sewer lyes - from this reclaim operation (streams
101319 and 103326) . All existing soap plants both make and process
soap. Therefore, the given categorization will handle the effluent
sewer lyes under process 101 or 103. Should a plant start with neat
soap, the sewer lye guidelines should be applied to 105.
Introduction
To produce soap bars, neat soap is dried and physically worked prior to
extrusion and stamping. Some plants have filter backwash (106129) ,
scrubber waters or condensate from a vacuum drier (106201) and water
from equipment washdown (106202 and 106302).
Wasterr Water Balance
Water from drying neat soap is vented to the atmosphere. Water use by
plants producing dry soap varies from none to 6230 1/kkg (750 gal/1000
Ib) of soap made. The largest quantity is required when a barometric
condenser is used on the drier.
Waste Water Constituents
The contaminant of all waste waters is soap which will contribute
primarily to BOD5 and COD. concentrations of BOD5 and COD are typically
1600 mg/1 and 2850 mg/1 respectively in the scrubber (106201), which is
the major source of contamination. Driers contribute from 0.3 - 0.7
kg/kkg (0.3 - 0.7 lb/1000 Ib) of soap to waste waters. Washouts of the
filter and of equipment account for the remainder to give an average
process total of 2 kg of BOD5 per kkg (2 lb/1000 Ib) of dry soap.
LI2 UIEL SOAPS — (PROCESS 107 )
Introduction
Production of liquid soaps consists of a simple blending operation
followed by filling of rather large containers (drums) for sale.
According to manufacturers interviewed, there is very little aqueous
effluent. Leaks and spills can be recycled or handled dry. Washout
between batches is usually unnecessary or can be recycled to extinction.
Water Balance
-------
Some water is used as a part of the liquid soap formula, and small
amounts (16.6 1/kkg of dry soap or 2 gal /1000 Ib) are occasionally used
for cleanup.
Waste Water Constituents
The liquid soaps will contribute to BOD5, COD, and dissolved solids.
However, amounts are very small (0.1 kg BOD5 and 0.3 kg COD/k kg of
product) (0.1 Ib BOD5 and 0.3 Ib COD /1000 Ib) .
QLEUM_gyLFONA,TION AND SULFATIQN — (PROCESS 201)
Introduction
The principle raw materials for synthetic • detergent manufacture are
alkylbenzer.es, fatty alcohols and alcohol ethoxylates. These are
converted to surface active agents by sulfonation or sulfation and
neutralization with sodium hydroxide or other bases. There are no
process waste waters from the oleum sulfonation and sulfation reaction,
leaks, spills and washouts result ir. some highly acidic wastes (streams
201102, 201202 and 201302). The oleum tank breathing scrubber which
collects S03_ vapors during filling of the tank also contributes sulfuric
acid to the waste waters (201101). Although cooling water is used for
the sulfonation, it is indirectly used to cool Freon or brine systems
and doesn't become contaminated.
Although the amount of acids released are small, both the sulfuric and
sulfonic acids are strong acids and small amounts can give a pH of 1 -
2; therefore, neutralization of spills is imperative. Also, the
sulfonic and sulfuric acid esters are surface active (NBAS) and
contribute to BOD5 and COD. some oil and grease can be expected from
spills of organic raw materials. The pH will be very low.
Watgr_and_Waste_Water Balance
Usually leaks from pump packing glands will be flushed away continuously
with small streams of water. Little water is used. Because the water
use is small, 100 - 2740 1/kkg (12-330 gal/1000 Ib) of surfactant,
potable water is generally used. Since the oleum tank scrubber will
only be used when the tank is being filled, little water is used here.
Since sulfonation is highly exothermic and temperatures must be kept low
to avoid charring, the cooling water for sulfonation is a large stream.
Well water or municipal water is preferred because of their low
temperatures making the refrigeration cycle more economical.
Waste^Water^Constituents
Since the source of contaminants is leaks and spills, all the raw
materials and products may be present. These are fatty alcohols,
dodecylbenzene, sulfuric acid, dodecylbenzene sulfonic acid, and the
65
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esters of sulfuric acid and alchohols. These chemicals will contribute
acidity, sulfate ion, MBAS, oil, BOD5 and COD to the waste water stream.
Concentrations of contaminants will depend on the amount of water used
for washdown. Amounts of contaminants average 0.2kg (0.2 Ib) BOD5, 0.6
kg (0.6 Ib) COD and 0.3 kg (0.3 Ib) MBAS per 1000 kkg (1000 Ib) of
sulfonated product. The pH will usually be very low (1-2) unless the
sulfonation wastes are commingled with neutralization wastes.
AIR-S03 SULFONATION £ SULFATION (PROCESS 202^
Introduction
Anhydrous SO3 is used to sulfonate aklylbenzer.es and to sulfate alcohols
and alcohol ethoxylates converting them to surface active agents. The
acids produced are neutralized with NaOH, ammonia and other bases as
described in process 206.
Because of the hazardous nature of anhydrous SO3_, the systems designed
for its use are essentially leak-free. However, any leaks and spills
will end up in the waste waters. The main source of contaminated waste
waters are by-products. The incoming air-SO3 stream will be scrubbed
with H2SOU and the spent acid purged (202309). The effluent gas
contains entrained sulfonic acid, sulfuric acid and SO2_ (202301).
Another sizable source (202302) of contamination comes from startup and
shutdown. Plants that run 7 days per week, 24 hours per day will
obviously have much less contamination from this source than plants that
shut down more frequently.
Water Balance
A considerable amount of water is used for cooling the sulfonation
reactor. This is usually a clean water stream. Approximately 249 1/kkg
(30 gal/1000 Ib) of water is used for disposing of by-products. All of
this water usually goes to the sewer.
Waste_Water Constituents
Stream 202303 which receives startup slop will contain unreacted
alcohols, alcohol ethoxylates, and alkylbenzenes. These will show up as
oil and grease as well as BOD5 and COD. The other contaminated streams
(202102, 202202, 202309 and 202301) as well as 202303 will contain
sulfonic and sulfuric acids. These materials affect MBAS, acidity, SOM;,
dissolved solids, BOD5 and COD.
Concentrations from the process were observed to range from 380-520 mg/1
of BOD5 and 920-1589 mg/1 of COD. The pH ranged from 2-7. Source of
the contamination comes from three streams; leaks and spills - 15
percent, scrubbers - 50 percent and startup slop - 35 percent.
g03_SOLYENT_AND_VACUUM SULFONATION — (PROCESS 203)
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Introduction
Compared to the Air-SO3 process, these techniques are used infrequently.
Usually they will be batch operations and relatively small. Leaks,
spills and washouts will be the main source of contamination. No data
specific to these processes was obtained or submitted, but it is be-
lieved that effluents and contaminants will be essentially the same as
for Air-SO3 sulfonation. Process 202.
Waste Water Balance
No direct process water will be used, but a small stream will be used
for cleanup of leaks and spills. Cooling water will be indirect. It is
possible that operators will use barometric condensers to maintain the
vacuum and to strip solvent, which is usually SO2. If barometrics are
used, there could be a large volume effluent with low concentrations of
MBAS, oil and sulfite.
Waste_Water Constituents
Leaks and spills will consist of raw materials and products. These will
include alkylbenzenes, alcohols and ethoxylated alcohols; sulfonic acids
and sulfuric acid esters. These constituents will contribute BOD5, COD,
acidity, dissolved solids, sulfate, sulfite oil, and MBAS to effluent
waste waters.
SULFAMIC ACID SULFATION — (PROCESS 204)
Introduction
Sulfamic acid is used to sulfate alcohol and alkylphenol ethoxylates,
but seldom for other raw materials. The reaction is run batchwise and
requires relatively simple equipment. The ammonium salt of the ether
sulfate is obtained directly, so it is only necessary to dilute the
product with the chosen solvent.
Water and_Waste_Water Balance
No process water is used and cooling or heating water will be non-
contact.
Waste Water Constituents
A small amount of contamination will come from leaks and spills, but a
major effluent comes from washing out the reactor between batches. This
is necessary since the solvent (water or alcohol) will react with the
sulfamic acid.
Data submitted by industry indicates that 30 kg (30 Ib) of BOD5 and 60
kg (60 Ib) of COD is added to waste waters per kkg (1000 Ib) of ammonium
ether sulfate produced. This is understandable since the product is
viscous and surface to volume ratio of the reactor is high.
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CHLOROSULFQNIC ACID SULFATION — (PROCESS 205)
Introduction
This process is used to produce high quality alcohol and ether sulfates
for specialty surfactant use. Leaks, spills and reactor washout will be
the main source of organic contaminants. Since HCl is a by-product it
may be absorbed in water or caustic and sent to the sewer.
Water and Waste Water Balance
The only process water used is for absorbing HCl. Cooling water is non-
contact and should remain uncontaminated.
Contaminants found in leaks and spills will be the alcohols or
alkylphenol and alcohol ethoxylates used for feedstocks. Also,
chlorosulfonic acid hydrolysis products (HCl and H2S04.) can be expected,
plus the sulfated surfactants. The same materials will be in the other
waste waters.
Since it is not necessary to clean out the reactor between batches, raw
waste loads will be similar to other sulfonation processes; i.e., S03-
Air. An average of 3 kg (3 Ib) of BOD5 and 9 kg (9 Ib) of COD per kkg
(1000 Ib) of sulfated product was found. Sizable amounts of acidity and
chloride (5 kg/kkg) (5 lb/1000 Ib) can also be expected if the HCl is
sent to the sewer, but many plants recover it and sell it as muriatic
acid.
NEUTRALIZATION OF gULFURIC A^ID ESTERS Z SULFONIC ACIDS — {PROCESS 206)
Introduction
This process is used to convert the sulfated and sulfonated
alkylbenzenes and alcohols to neutral salts. Various bases are used
depending on the required characteristics of the final surface active
agent. The dry neutralization process (2063) is infrequently used in
the United States to make consumer products falling within SIC 2841.
However, some industrial products will be made. Most salts are made by
liquid neutralization (2062) . Plants making neutralized products range
from a small batch kettle of a few thousand kilograms capacity to
several million kilograms per day continuous process unit.
Water_and^Waste_Water_Balance
Waste waters from these plants come almost entirely from leaks and
spills, with washouts occasionally contributing (206102 and 206202).
Indirect cooling water is used since the neutralization is exothermic,
but contamination should be very rare. No process water is involved.
Wagte^Water^Constituents
All of the anionic surface active agents used in soaps and detergents
will be found in these waste waters. Also the inorganic salts, such as
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sodium sulfate, from neutralization of excess sulfuric acids will be
found. Alkylbenzene sulfonates, ether sulfates, alcohol sulfates, ole-
fin sulfonates, with the ammonium, potassium, sodium, magnesium and
triethanol ammonium cations will be represented.
These constituents will contribute to BOD5 and COD, MBAS dissolved
solids, Kjeldahl ammonium nitrogen, sulfate, acidity and alkalinity.
The total amount of contaminants contributed from this process is quite
small. The equipment used has stood the tests of time. Of course there
will always be occasional leaks and spills. Whether a plant recycles
or discharges to a sewer determines the concentration of contaminants
and water usage. When recycle is practiced, as little as 10.4 1/kkg
(1.25 gal. /1 000 Ib) of water is used. Concentrations in this case were
high - 6000 mg/1 of BOD5 and 21,000 mg/1 of COD. The other extreme was
4170 1 (1100 gal.) of water - a BOD5 of 85 mg/1 and a COD of 245 mg/1.
Because of the variety of products made we observed quite a range of
waste loadings: BOD5 - 0.07 kg - 0.8 kg/kkg (0.07 Ib - 0.81b/1000 Ib)
of product, COD - 0.2 kg - 2.3 kg (0.2 Ib - 2.3 Ib) , MBAS - 0.1 kg - 3.1
kg (0.1 Ib - 3.1 Ib) .
ED_ DET ERGENTS_- - (PROCESS 207J
Introduction
This is probably the single largest volume unit process utilized by the
soap and detergent industry. There is great variation in the operation
of spray towers insofar as water use and reuse is concerned.. These
variations result from different processing characteristics of product
formulas, influences of air quality problems, standards and frequency of
product changeovers, and plant integration.
The principal sources of contaminated water are washdown of the tower
207312; scrubber waters - 207301 and 207330; and leaks and spills -
207202 and 207302.
Wat er_and_Waste Water Balance
No cooling water is used in this process. All process water which is
added to the crutcher leaves the process as water vapor from the spray
tower (207308). Therefore, all water used is for various types of
cleanup. Some plants employ total recycle of cleanup water and
therefore have a very low rate of discharge. Some plants discharge all
waste waters to the municipal sewer. Most plants are intermediate and
specific problems must be recognized to be able to understand water
disposal practices.
To be able to maintain desirable air quality it may be necessary to use
very large quantities of water for scrubbing organics from spray tower
vent gases. This problem is still under study. Frequent product
changeovers for smaller plants make it economically and physically
impossible to collect and recycle all tower washouts. Highly integrated
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plants have more opportunities to recycle or use detergent-laden waste
waters.
Waste Water Constituents
All of the streams will be contaminated with the detergent being
produced in the plant at the time. The various surfactants, builders
and additives are listed on the flow diagram entering 2071 Receiving
Storage And Transfer.
These constituents will contribute to BOD5, COD, MBAS, dissolved and
suspended solids, oil and grease and alkalinity.
Average raw waste loads for the three types of operation of spray towers
are tabulated as follows (kg/kkg dry detergent) (lb/1000 Ib):
BOD5 COD Suspended Oil and
Solids Surfactants Grease
Few turnarounds &
no air quality
problem 0.1 0.3 0.1 0.2 nil
Air quality
problems 0.8 2.5 1.0 1.5 0.3
Fast turn-
around 0.2 0.4 0.2 O.U 0.03
LIQUID DETERGENT MANUFACTURE " (PROCESS 208)
Introduction
Manufacture of liquid light-duty hand dishwashing and heavy-duty laundry
detergents requires relatively simple equipment for blending the various
ingredients. Usually this is done batchwise with the several
surfactants being added by weight, and then thoroughly blended.
Filling of the bottles is done on sophisticated high speed filling
lines. This is a most critical and difficult operation because of
machine complexity, speed, and cost.
From the filling line, leaks, spills and overflows are sources of water
contamination (208302). From both the blending and filling operations,
purging the lines between products produce slugs of detergent
contaminated water (208212, 208213 and 208302). Also, filled detergent
bottles are sometimes washed (208310).
Contaminants from light-duty liquid detergents are very high in surface
active agents. Heavy-duty liquid detergents, produced in much lower
volume, can result in some contamination with builders (phosphates,
carbonates) .
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Water^and Waste_Water Balance
Liquid detergents consume water as the major solvent for the product.
Little or no water is used for heating and cooling, but large amounts of
water are used for washing equipment and packages. Because very small
amounts of liquid detergents can cause extraordinary amounts of foam, it
is necessary to use very large volumes of water; and recycle or reuse of
water becomes impracticable. Reported water usage was in the range of
625-6250 1/kkg (75-750 gal/1000 Ib) of detergent.
H§§ t e_Wa t er _Con s t i tue nt s
All of the effluent streams will contain the starting ingredients of the
products. These are mainly:
ammonium, potassium & sodium alkylbenzene sulfonates (LAS)
ammonium, potassium & sodium alcohol ethoxy sulfates (AES)
ammonium, potassium & sodium alkylphenol ethoxy sulfates
ammonium, potassium & sodium olefin sulfonates (OS)
ammonium, potassium & sodium toluene and xylene sulfonates
(hydrotropes)
ammonium, potassium 6 sodium alcohol sulfates
Fatty acid alkanol amine condansates (amides)
Urea (hydrotrope)
Ethanol (hydrotrope)
Polyacrylates and polystyrene (opacifiers)
Dyes & perfume
Phosphate & citrate builders
Silicate builders
These constituents will contribute to alkalinity, BOD5, COD, nitrogen,
MBAS (and undetected surfactants) and dissolved solids.
Raw waste loadings vary more in concentration than total amount between
plants. The following were observed:
kg/kkg of detergent mg/1
BOD5 0.5-1.8 65 - 3UOO
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COD 1.0 - 3.1 120 - 7000
MBAS 0.4 - 1.1 60 - 2000
As much as 90 percent of the detergent can come from washout of tanks
and lines when changing products. With fewer changes waste loads will
decrease, but the lower levels in the above table represent minimum with
current practice.
DETERGENT MANUFACTURING BY DRY BLENDING — (PROCEgS 209)
Introduction
Production of detergents by this process requires no water for
processing and can be operated without using water for washdown. Dry
builders and surfactants are simply mixed, or liquid surfactants are
sprayed into dry powders so that the entire mass stays free flowing.
Some water may also be sprayed onto the dry powders to produce more
stable hydrates.
DRUM DRIED DETERGENTS_-- ^PROCESS 210)
Introduction
In this detergent drying process, the aqueous slurry of detergent is
dried on steam heated rolls and recovered as flakes. Little or no
formulated household detergent is now made by this process. Most of the
products are high active LAS products for dry blending of industrial
detergent products.
Water and_Waste Water Balance
The detergent slurry contains water added in the neutralization process
No. 206. This water is removed as steam and vented to the atmosphere or
scrubbed (201201). Steam condensate is generated also, but this should
be free of contamination (210203).
Wa s te _Water_Constituents
The only appreciable effluent will be similar to, but lower in
concentration than the scrubber water from spray drying (207301).
Surfactants, builders, and free oils can be expected. These will
contribute to BOD5, COD, alkalinity, MBAS, dissolved solids and oil and
grease.
DETERGENT BARS AND CAKES — (PROCESS 211)
This process is similar in operation to Process 106 Bar Soaps. The
significant difference arises in the more frequent washouts required
because of the heat sensitivity of the detergent active ingredient.
Wash waters will be similar in character to those of spray dried
detergents.
72
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In some instances soap will also be found in the waste water since it is
a part of the blend comprising some toilet bar soaps.
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SECTION VI
POLLUTANT PARAMETERS
Int.ro duct ion
This section contains a discussion of the specific contaminants which
were selected for guidelines recommendations, and those which were
omitted. Rationales for the decisions are given for each pollution
parameter.
Production of soaps and detergents results in numerous waste water
streams and several types of contaminants which are of special concern.
Synthetic surface active agents not or.ly create a BOD5 and COD, but also
cause water to foam and in high concentrations can be toxic to fish and
other organisms. Nutrients, particularly phosphate, are of concern
because of their contribution to eutrophication of lakes. Soap
production leads to waste waters with high alkalinity, high salt, and
high oxygen demand. Spills of raw materials contribute to oil and
grease levels. Most of the suspended solids come from organics; i.e.,
calcium soaps, and many are of the volatile rather than non-volatile
type. Since strong acids and strong alkalies are used, pH can be very
high or very low in waste waters.
CONTROL_PARAMETER RECOMMENDATIONS
To monitor the quality of the treated waste water flows coming from soap
and detergent plants as point source discharges, the key parameters
recommended for sampling and analysis and structure of guidelines are:
Biochemical Oxygen Demand
All of the organic active materials found in soap and detergent
formulations are biodegradable in varying degrees. Most are totally and
rapidly assimilated. Although highly criticized for its lack of
reliability, the analytical method for BOD5 is still the only generally
accepted method for grossly measuring the potential impact on the
environment. Unfortunately, not all of the organic materials found in
these waste water flows contribute to the oxygen demand at the same
rate. Some may inhibit the microorganisms which degrade these
contaminants, and others are incorporated into the cell tissue of the
microorganisms at different rates. This leads to varying ratios of BOD5
values when compared to the companion COD test.
There are a number of factors which tend to reduce reliability of the
BOD5 in actual practice. One difficulty stems from the frequent need
for long term acclimation of the biota to the special unique organic
substrates encountered in the waste streams from the manufacture of
detergents. Too often biota are employed in the BOD5 tests which are
totally unacclimated, or at best only partially acclimated. When data
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derived from such testing are viewed in isolation they tend to indicate
that a large quantity of such organics are resistant to biodegradation
or are only slowly degraded. However, detailed studies carried out with
thoroughly acclimated microbial systems do not support this casual
observation. In fact, the vast bulk of the materials now employed as
synthetic detergents are subject to rapid and complete assimilation by
acclimated saprophytic microorganisms. Industrial surfactants
production does lead to a higher refractory component than the household
surfactants.
The use of the BOD5 test is recommended. However, it is essential that
acclimated biota be maintained especially where the concerned effluent
originates from a plant producing industrial cleaners.
Chemical_OxY^en _Demand
The COD or chemical oxygen demand is a companion test and internal check
on the biochemical oxygen demand. COD/BOD5 ratios of 2 - 3/1 indicate
complete or virtually complete susceptibility to biochemical
assimilation. Ratios greater than 3 indicate that the material being
tested is toxic to the bacteria, inhibitory or resistanr to biochemical
attack. Because of the difficulty discussed in the preceding section
concerning the reliability of the BOD5 test, it is recommended that the
COD be used as a primary parameter where acclimated biota cannot be
readily obtained.
The COD test, however, is not without some special problems of its own.
Volatile substances such as low molecular weight hydrocarbons can escape
before oxidation. Also, long chain fatty acids which are commonly found
in the waste streams from soap manufacture, are slowly oxidized in the
COD test. Special attention must be given to insure the complete
oxidation of these materials.
Suspended Solids
Although the waste water sources of the soap and detergent industry are
not notably heavy in suspended solids, suspended solids should be
monitored to insure that stream clarity is not unduly affected,
particularly by some upset in the processing train.
Surfactants JMBAS)
Because of the possible contribution to foaming in streams and
biological upset, measurement of the organic active ingredient in
formulations is necessary. Not all organic active materials are
measured by this method. Soaps are not detected, nor are non-ionics.
However, both of the latter are measured by the BOD^ and COD methods.
Oil and Grease
These materials which would contribute to esthetic problems as well as
to oxygen demand need to be controlled. The analytical method picks up
not only the fatty oils and grease used in the soap making process, but
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any hydrocarbon bodies which are generated from the synthetic detergent
portion of the plant processes. The test method does not distinguish
between the two sources, therefore the results must be interpreted with
discretion.
EM
This is important for control since there are occasional upsets in those
portions of the processes which could potentially lead to highly acidic
or alkaline spills.
Parameters Omitted
Among the parameters omitted is dissolved solids. While there will be
times of high concentrations of salts in some of the waste water flows
within the plant, by the time they are commingled with the total plant
effluent they will be quite dilute. In addition, the salts themselves
are not in a toxicity range of concern. Most of them are found as
deliberate additions to food in other manufacturing processes. If the
contamination of the waters by dissolved solids could be damaging, the
permit granting authority should then issue specific guidelines covering
that particular situation.
Nitrogen
Nitrogen, although important in the general concern over the quality of
the receiving waters, is omitted since there is at this time very little
use of products derived from nitrogen. Spot checks of industrial
effluents and contractor's analysis of Corps of Engineers permit
applications confirmed this observation.
Phosphorus and_ Boron
Phosphate and boron levels found in the raw wastes and treated effluents
from plants manufacturing soaps and detergents are comparable to those
encountered in the influents and effluents of well operated municipal
treatment plants. Moreover, measures to control the selected parameters
will effectively control phosphate and boron levels.
Scope of Parameter Measurements - By Processes
Each of the individual processes of the soap and detergent industry are
reviewed in the following paragraphs in order to relate the significance
of the parameters chosen for guidelines to the measurement of the
contaminants contained in waste water flows originating in each unit
process.
The ways in which effluent discharge can be monitored are suggested.
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SOAP_MANUFACTURE BY BATCH KETTLE (101)
Significant contaminants from this process are the fats and oils used as
raw material; unrecovered sodium chloride, sodium sulfate and sodium
hydroxide; soaps that are spilled or lost and dark colored by-product
soaps. Limits are proposed for BOD5 and COD, suspended solids, oil and
grease and a range of 6 - 9 for pH. The soaps, fats and oils will be
controlled by the first four tests. A pH in the 6-9 range will insure
against discharge of sodium hydroxide or strong acids.
Since soap plant wastes can cause depletion of dissolved oxygen,
limitation is necessary. Oils and suspended solids cause esthetic
problems. A very high or very low pH is detrimental to almost all
organisms.
No recommendation has been made for specific limitations of the two
inorganic salts, NaCl and Na^SO^. These are relatively non-toxic (NaCl
10-20,000 mg/1 MLD; Na2S04 11-17, 600 mg/1 MLD), and most receiving
waters are below the limits of dissolved salts set by the United States
Public Health Service.
FATTY ACIDS BY FAT SPLITTING J102)
The organic compounds from this process are primarily fatty acids
although some unreacted fat and glycerine from spills and leaks will
also be found. The total of the inorganics will be low compared to the
organics. Sodium hydroxide and sodium sulfate from fat pretreatment and
from treatment of still bottoms are expected.
Total organics should be controlled by setting BOD5 and COD limits.
Free fatty acids and fats should be controlled by setting oil and grease
and suspended solids limits. The pH should be controlled.
Contaminants not limited are the generally innocuous sodium sulfate plus
small amounts of zinc and alkaline earth metals used as the fat
splitting catalyst and nickel used as a hydrogenation catalyst. These
metals ions are below harmful concentration in commingled plant wastes
and are removed in biological treatment processes which must be used on
the organic contaminants.
SOAP BY FATTY ACID NEUTRALIZATION (103)
Except for fats and oils the contaminants from this process will be the
same as from the kettle boil soap process. Concentrations and loadings
are much lower, however.
Control of discharge is established by setting limits on BOD5, COD, pH,
suspended solids and oil and grease.
The small amount of sodium chloride relative to the production of soap
should not require regulation unless the receiving stream is at a
critical chloride level.
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GLYCERINE RECOVERY (
Contaminants in waste waters from this process are water soluble
organics and two inorganic salts. The organics are glycerine and
glycerine polymers. The salts are Nad and Na2S04.
Organics discharge is controlled by setting BOD5_ and COD limits.
Although pollutants affecting pH, suspended solids, and oil and grease
are minimal, limits have been set to guard against carry over from
previous processing steps.
Sodium chloride and sodium sulfate should not be restricted unless the
receiving stream is close to the specified limit for chloride and
sulfate ions.
SOAP FLAKES AND POWDERS (105)
Effluents from this process are minimal. Since almost pure soap is
processed, the contaminants will be primarily soap with only small
amounts of free fatty matter, alkali and salt.
BOD5 and COD are used to limit discharge of soaps, and pH is to be kept
to the 6-9 range. Suspended solids and oil and grease should be
measured to guard against unusual contamination.
Although sodium chloride is not limited, its concentration should be
negligible.
BAR SOAPS (106)
As with soap flakes and powders, waste water contaminants from this
process will be mainly soap. Small amounts of salt and alkali which are
in the soap will also be found. Some free fatty matter and additives
can be expected in the waste waters.
Assignment of BOD!5 and COD limits will control the discharge of soap.
Specifying limits for pH, oil and grease, and suspended solids will
handle unusual spills.
Inorganic contaminants should be low and control should be unnecessary.
LIQUID SOAP j 10 7)
Liquid soaps are formulated products and will contain solvents,
builders, dyes and perfumes in addition to potassium soaps. Almost all
contamination will come from spills so the waste water will be
contaminated with all constituents of the formula.
BOD5 and COD limits will control overall discharge of organics. Control
of pH to the 6.0 - 9.0 level should present no problem since the product
will be in that range. The suspended solids and oil and grease tests
will be more important here than with other soaps since the formulated
soaps often contain hydrocarbon solvents.
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Inorganic salts should be negligible from this process and thus require
no control. Potassium ion will be found here but the level should be
low enough to require no limitations.
QLEUM_SULFONATION_AND_SULFATION (201)
In effluents from this process, one can expect to find the oily raw
materials, sulfuric acid and surfactant sulfonic acids. All of these
contaminants need to be treated before discharge.
Raw material spills should be limited by setting specifications for the
oil and grease and suspended solids. The MBAS test can measure surface
active sulfuric acid esters and be used to limit their concentration.
Total organic contamination can be monitored and controlled by running
the oxygen demand procedures, BOD5 and COD. Sulfuric acid and sulfonic
acids are very strong acids and must be neutralized before discharge.
This can be assured by specifying a pH of 6 - 9.
The only contaminant not limited is sulfate. Most streams can absorb
current quantities of this ion, but if necessary the regional permit
officer can restrict discharge of sulfate.
AIE_gQ3_SULFATIQN_-_syLFONATION_j[202]_
This process is identical to process 201 with respect to contaminant
composition. However, the levels of contamination are higher.
Limitations have been set for BOD5, COD, pH. oil and grease, MBAS and
suspended solids. Sulfate need not be limited for the usual receiving
water.
See the discussion under Process 201 for the rationale.
VACUUM AND SOLVENT SULFONATION (203)
This process is identical to process 201 insofar as contamination is
concerned. One exception is the possible presence of sulfate in the
waste water. Levels should be similar to process 201.
Limits have been set for BOD5, COD, pH, oil and grease and suspended
solids. Sulfate should generally be exempted.
For rationale see Section 201.
SyLFAMIC_ACID_SyLFATION_^2041
This reaction is rather limited in scope, but can have a high discharge
because of washdown after each batch. Contaminants will be unsulfated
ethoxy alcohols, sulfamic acid and ammonium ether sulfates.
The MBAS test and a limitation for the process will be most useful for
control. Because the MBAS test does not pick up nonionic surfactants.
80
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3OD5 and COD are needed to control the overall organic load. As usual,
DH control will be needed since sulfamic acid is a strong acid.
3ulfamic acid hydrolyzes to ammonium acid sulfate in water so that no
control is needed unless the receiving water is close to its limit for
litrogen and sulfate.
The organic contaminants from this process will be feedstock, fatty
alcohols, alcohol ethoxylates and alkyl phenol ethoxylates. Also, the
sulfated products and the final ammonium, sodium and triethanol amine
salts will be found. Inorganics will be hydrochloric and sulfuric acids
plus ammonium and sodium ions.
limitations have been established for total organics by specifying EOD5
and COD values. MBAS should be measured and controlled. Raw material
spills can be controlled by specifying suitable values for oil and
grease and suspended solids. As usual, pH needs adjustment to the 6.0 -
9.0 level.
NEUTRALIZATION OF SULFURIC ACID_ESTERS_AND_SyLFONIC_ACIDS_i2^6i
In this process the organic acids produced by sulfation and sulfonation
are reacted with bases to produce the desired salts. Therefore,
contaminants will be the products of processes 201,202 and 203. In
addition, the neutralized products and the various cations will be
present.
The MBAS test, and a limitation thereon, will be important in
controlling contamination from this process. BOD5 and COD allowances
will determine overall organic contamination. To assure a neutral waste
water, pH adjustment will be necessary. Oil and grease and suspended
solids should be minimal but specifications are needed for unusual
spills.
Control of inorganic sulfate, potassium, sodium and ammonium ions is
believed unnecessary for most receiving streams.
SPRAY DRIED DETERGENTS (2071
Effluents from this process will contain all of the many ingredients
used in dry detergent powders: LAS, amide, nonionic and alcohol sur-
factants: sodium phosphate, carbonate and silicate builders;
carboxmethyl cellulose, brighteners, perborate, dyes, fillers and
perfumes.
An MBAS limit will handle anionic surfactants, but COD and BOD5 tests
are needed to estimate other surfactants. Careful attention needs to be
paid to BOD5/COD ratio since the various surfactants can inhibit or
react slowly with unacclimated BOD5 cultures.
The suspended solids test will serve to limit insolubles and the oil and
grease limit is needed for spill of oils from the spray tower.
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Specific limits have not been recommended for carbonate, silicate,
phosphate and sodium ions. The condition of the receiving stream should
be determined by the permit officer before limiting these contaminants.
LIQUID DETERGENTS £20 81
These products are made by simple blending so effluents will contain the
starting ingredients. High levels of organic surface active agents can
be expected from washdown and cleanup. Heavy-duty liquid detergents
will also contain potassium phosphate, silicate and citrate builders and
solvents (ethanol). Hydrotropes (sodium xylene sulfonate and urea) will
also be found.
To control total organics the BOD5 and COD levels have been specified.
MBAS limits have been set to control the important anionic surfactants.
Limits on pH, oil and grease, and suspended solids have been set but
control measures should be unnecessary.
Except for the generally innocuous inorganic salts, levels for all
contaminants have been specified.
DRY_DETFRGENT_BLENDING__(2091
This process usually has a very low effluent level. Any contaminants
will be the same as those discussed in Section 207 - spray dried
detergents. Our rationale for limiting BOD5, COD, pH, suspended solids,
MBAS and oil and grease are the same also.
DRU5L DRIE D_ D JET ERGE NT S_X21.0 j_
Almost exclusively devoted to the manufacture of industrial detergent
powders, this process uses a wide variety of raw materials. They find
their way into waste water flows through spills and washouts. BOD5, COD
and surfactant (MBAS) limits will govern these sources, coupled with pH.
There should be no oil and grease appearing in any waste water from this
process.
DETERGENT_BARS_AND_CAKES_I2111
Processing of detergent bars is almost identical with soap bars.
However, the wastes will contain synthetic surfactants. Therefore, in
addition to setting limits on BOD5, COD, pH, suspended solids and oil
and grease, it is necessary to specify a limit on MBAS.
The rationale for the limits and parameters will be found under process
106.
Industrial^Cleaners
Industrial cleaning compounds are also manufactured in plants of the
soap and detergent industry. Insufficient data was obtained to make
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specific recommendations on the multitude of compounds employed but some
guidance can be given. Industrial cleaners make up about 10 percent of
the industry output. The studies of the Organic and Inorganic Chemicals
Industries are expected to provide much useful treatment aata on some of
the more exotic chemicals. The phosphates, silicates, carbonates and
caustic alkalis which are employed will create the same basic situations
as are discussed in processes 207, 208 and 209. Similar treatment
procedures and guidelines also apply.
Other material not sufficiently characterized but which might be
expected in the industrial waste waters are hydrogen fluoride, sulfamic
acid, phenols and cresol, chlorinated hydrocarbons, complex organic and
inorganic corrosion inhibitors, and exotic surfactants. Fluorides can
be easily precipitated with lime. Sulfamic acid and cresol are readily
biodegradable if concentrations are kept low. The chlorinated
hydrocarbons may have to be removed by solvent extraction or carbon
absorption. Some corrosion inhibitors used in acids for industrial
cleaning are complex organics which will require individual study. The
exotic surfactants will include phosphoro-, fluoro- and silicoorgano
compounds which have unknown treatability. Nonionic, amphoteric, and
low molecular weight wetting agents with different treatability can also
be expected. The limits on EOD5, COD, suspended solids, surfactants,
oil and grease and pH should effectively control industrial cleaners in
the subcategories involved in their production, but the area of
industrial cleaners merits additional study.
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SECTION VII
CONTROL AND TREATMENT TECHNOLOGY
Introduction
The key to great reductions in the pollution load from the soap and
detergent industry is lower process water usage. Those processes using
the most process water per unit mass of product made are also the
greatest contributors of pollutants.
One of the biggest improvements would be either changing the operating
techniques associated with the barometric condensers or replacing them
entirely with surface condensers. complete replacement would reduce
many fold the use of water in most processes and at the same time cut
down greatly on the amount cf organics now being sent to sewer. These
organics normally have a market value (when further purified) which may
provide a positive payout on the improvement introduced.
Barometric condenser operation could be greatly improved by recycling
the water through a fat skimming operation (where marketable fats and
oils could be recovered) and then through cooling towers. Tne only
waste would be a continuous small blowdown from the skimmer to keep
soluble materials within acceptable limits. Fat splitting operations
which have barometric condensers equipped with such cooling and skimming
equipment already meet the recommended guidelines with considerable
ease.
Another area where a large reduction in water usage could be effected is
in the manufacture of liquid detergents. This can be attained by
installation of additional water recycle piping and tankage and by the
use of air rather than water tc blow out filling lines. This latter
change will also minimize the loss of finished product.
One of the large integrated plants making both soaps and detergents has
achieved almost zero discharge of pollutants through a painstaking,
ten-year effort. One of the first tasks which had to be undertaken, and
still the biggest obstacle for most fairly old integrated plants, was
identifying and untangling the waste water lines which now lead to the
sewer. Only after such identification, monitoring and study could the
effluents be managed better.
With few exceptions, the contaminants in waste waters from the soap and
detergent industry are really saleable products in disguise, especially
those relating to distillation equipment and entrainment separators.
Wherever a distillation is carried out, whether on a batch basis or by
multi-component continuous fractionation, there is an entrainment of
liquid droplets from one tray of a tower to the tray above. This is
essential in order to accomplish good vapor-liquid contacting and to
make the efficiency of the physical transfer of the highest possible
order. However, it does result in carrying droplets of liquid by the
vapor from the stage below to the stage above. The use of one or two
additional special trays in a distillation column, whether used in con-
85
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centration as in glycerine manufacture or used for the separation of
components as in fatty acid manufacture, will not only eliminate
carryover in the form of entrainment but will lead to a more complete
separation and a higher purity of each component of a multi-component
distillation feed.
NATURE_OF POLLUTANTS
The soap and detergent industry freduces wastewaters containing both
conservative and nonconservative pollutants which must be treated,
removed from the waste stream, and ultimately disposed of under
controlled conditions. The important nonconservative pollutants consist
of organic raw materials, fats ard oils and lost portions of finished
product, soap and/or synthetic detergent. Mineral solids, catalysts and
builder materials such as borate ard phosphate also appear in the
effluents in moderate concentrations. Some of these substances reach
polluting concentrations in plant effluents which then have to be
treated. The pollutants of primary concern, together with the con-
centration ranges within which they are generally round in plant raw
waste effluents are as follows:
1. Oils and greases (0-3400 mg/1)
2. Suspended organic material other than oils and
greases (0-30,000 mg/1)
3. Dissolved or finely dispersed colloidal organic
substances which contribute to the chemical and
biochemical oxygen demands. (100-12,000 mg/1)
4. Certain organics with surfactant properties.
(0-1700 mg/1)
In addition to pollutants per se, the alkalinity or acidity of wastes is
also a primary concern and may mandate the treating of a plant effluent.
Of secondary concern in raw wastes are the following pollutants:
1. Boron or borates (less thar 1 mg/1)
2. Phosphates (25-1000 mg/1)
3. Dissolved mineral solids (0-250,000 mg/1)
4. Zinc and barium (less than 1 mg/1)
Since phosphate compounds are used in the manufacture of several types
of detergent, some of them inevitably find their way into the process
waste streams. The concentrations actually measured vary widely and the
data are not sufficiently complete to make absolute judgments concerning
typical levels for many of the operations carried out in tne industry.
However, some generalizations can be made.
In the closely controlled, well operated, integrated manufacturing
facilities examined as a part of the present study, where phosphoric
acid type cleaners were not being produced, the concentrations of
phosphorus contained in the combined raw waste was generally under 25
mg/1 as phosphorus. In those same facilities the average concentrations
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were typically 5-10 mg/1 as phosphorus; i.e., of the same order as is
contained in domestic sewage.
Table 2 indicates the treatment technology which can be applied to the
appropriate waste streams for removal of specific pollutants of concern.
DISCUSSION,OF_TREATMENT_TECHNIQUES
The treatment technology proposed is standard and in routine use.
Operating and design techniques are well established and have been
reported upon extensively in the literature. Therefore, only a brief
discussion of such operations and processes is included in this report.
A list of the major pollutants and treatment methods usually employed to
handle them are given in Table 2. Removal efficiencies for some of
these treatment methods are given in Table 3.
Oi.]1_and_Greas_e_Removal - This may be accomplished by the application of
any one, or a combination of three basic separation methods - gravity
separation, physical filtration, or adsorption. The gravity separators
are designed to handle loads of 20,500-41,000 1/day/sq m (500-1,000
gpd/sq ft) of surface. The filters are normally operated at 205-615 1
/min/sq m (5-15 gpm/sq ft).
Carbon and other related solid phase adsorption operations require
approximately 0.45-0.68 kg (1.0-1.5 Ib) of adsorbent per 0.45 kg (1 Ib)
of oil removed. Flotation operates very much the same as the
sedimentation operation in terms of over-all efficiency. Air rates are
usually maintained around 0.004-0.011 cu m/min/cu m (0.5-1.5 cu
ft/min/100 gal) of recycled flow. Chemical doses of Fed3, alum, or
lime vary from 50-150 mg/1.
87
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TABLE 2
Pollutants
Free and emulsified
oils and greases
Suspended Solids
Dispersed Organics
Dissolved Solids
(Inorganic)
Unacceptable Acidity
or Alkalinity
Sludge obtained from
or produced in
process
Treatments
1. Gravity separation
2. Coagulation and sedimentation
3. Carbon adsorption
4. Mixed media filtration
5. Flotation
1. Plain sedimentation
2. Coagulation-sedimentation
3. Mixed media filtration
1. Bioconversion
2. Carbon adsorption
1. Reverse osmosis
2. Ion exchange
3. Sedimentation
4. Evaporation
1. Neutralization
1. Digestion
2. Incineration
3. Lagooning
4. Thickening
5. Centrifuging
6. Wet oxidation
7. Vacuum filtration
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Pol 1 ut a nt ^a n d_rMe t hod
Oil and Grease
API type separation
Tabl€ 3
Efficiency (Percentage of Pollutant Removed)_
Up to 90 percent of free oils and greases.
Variable on emulsified oil.
Carbon adsorption
Up tc 95 percent of both free and
emulsified oils.
Flotation
Mixed media filtration
Without the addition of solid
phase, alum or iron, 70-80 percent of
both free and emulsified oil.
With the addition of chemicals,
90 percent
Up to 95 percent of free oils.
ciency in removing emulsified
cils unknown.
Effi-
coagulation-sedimentation
with iron, alum or solid
phase (bentonite, etc.)
Sugpended Solids
Mixed media filtration
Coagulation-sedimentation
Up to 95 percent of free oil. Up to
90 percent of emulsified oil.
70-80 percent
50-80 percent
Chemical Oxygen Demand
Bioconversions (with final
clarifier)
60-95 percent or more
Up to 90 percent
Carbon adsorption
Residual Suspended Solids
Sand or mixed media filtration 50-95 percent
Pissolved^Solids
Ion exchange or reverse osmosis Up to 99 percent
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Coagulation and §e^d_irnervt^at_ion - These units are designed to provide
between 30 and 60 minutes of coagulation time and are normally designed
for surface loading rates of 16,400-61,500 I/day sq m (400-1500 gpd/sq
ft) depending upon the nature of the waste.
Bioconyersion Systems - Bioconversion is a biological method of removing
pollutants from waste water. Its use involves one or more of the
following:
1 . Aerated lagoons
2. Extended aeration
3. Activated sludge
4. Contact stabilization
5. Trickling filters
While both aerobic and anaerctic sludge digestion are bioconversion
processes, they are not used to /remove pollutants directly from the
waste stream but rather to further treat materials already removed or
currently being generated as a part of the treatment operation.
Bioconversion units based on the use of activated sludge or one of the
basic modifications thereof are designed en the basis of 90-363 mg (0.2-
0.8 Ib) of COD per 0.45 kg (1 Ib) of dry biomass. Depending upon the
nature of the organics, this loading will provide removals in excess of
80-90 percent. Trickling filter systems are designed in a more
empirical fashion using one of the many formulae in the literature
relating efficiency to a real loading depth, recycle rate and hydraulic
load.
Carbon Adsorption Systems - These are of two general types; those which
use a more or less fixed carbon bed, and those which use powdered carbon
and recover the spent carbon in an accompanying clarifier. The carbon
is usually loaded at rates of 45-227 a (0.1-0.5 Ib) of pollutant per
0.45 kg (1 Ib) of carbon. At conventional surface loadings, spent
powdered carbon is easily recovered in a clarifier after coagulation
with inorganic salts or organic polyelectrolytes.
Carbon regeneration is a comparatively new art. While some regenerative
type systems do exist, they are neither common nor completely
satisfactory, In carbon regeneration, there are a number of
technological questions still to be answered. For example, movement of
the carbon to the furr.ace, attrition rates, control of oxygen to prevent
explosion. All of these questions should be carefully examined prior to
entering upon a major program utilizing the carbon adsorption waste
treatment process. However, if the nature of the wastes to be treated
clearly indicate the desirability of using the process, the above
considerations should not be viewed as absolute deterrents.
Fil1tration_for_Removal1_cf_Susp_ended Solids_ _ S'ie discussion of oil
removal.
Dissolved Solids Removal - The design of systems for this purpose varies
widely with the manufacturer. They are evaluated on the basis of
efficiency, water recovery, and the tendency to foul in the presence of
90
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suspended material. Most systems require the removal of most of the
solids prior to treatment. Some require virtually complete removal.
Dver-all water recovery tends to vary from 65-90 percent depending upon
the particular system employed and the nature of the waste.
2th§I_Treatment_Tec^nigue_Consi.deratigns - In a good part of the soap
and detergent industry, the conversion of raw materials and the recovery
Df reaction by-products is carried out on a batch rather than a
continuous basis. This results in effluent streams which flow
sporadically and vary greatly in content and volume. Because of this,
nost soap and detergent plants have devised ways of offsetting such
irregular performance and obtaining effluent streams of a more constant
lature, usually by providing some system capacitance, frequently in the
form of an equalization basin.
dhile it is not recommended that provision.be made specifically for the
control of phosphorus, it is recognized that a certain amount of
phosphorus is normally degraded in the normal course of waste treatment.
The following discussion is presented to indicate how this occurs.
rfhen in the coagulation and sedimentation unit waste treatment process
lime, alum or a combination of iron salts is used as tne primary
coagulant for the removal of suspended or colloidal material, the
removal of phosphorus may be carried out concomitantly by making minor
adjustments in the mode of operation and the handling of the sludge. In
nany cases, a high degree of removal will be obtained with no change in
the standard operating practices. It depends upon the pH levels
employed in lime coagulation and the level of aluminum or iron salts
employed in polyelectrolyte coagulation. In general, this procedure
vill produce phosphorus levels well under 1 mg/1 and under 0.5 ma/1
vhere an extremely high level of sedimentation performance is obtained.
In the above mentioned waste treatment process, some phosphorus is
removed as the phosphate salt of the metal cation employed in the
coagulation step. In the case of lime precipitation, pH values in
excess of 9.5 are generally required for a high level of removal. The\
actual value depends on the background calcium in the waste stream and
:he level of removal required. in the case of ferric or aluminum
phosphate precipitation, 1-3 times the stochiometric quantity will be
required for a high degree of removal. As can be seen, these quantities
Df material do not represent a major addition to the chemical
requirements and indeed a high level of phosphate removal may be
incidental to suspended and colloidal solids removal. Where phosphorus
removal is practiced as a part of an over-all waste treatment operation
which includes bioconversion, a sufficient level of pnosphorus must
remain in the stream flowing to the biological system to support
licrobial action. Or. a weight basis, this is generally of the order of
200 units of COD for each unit of phosphorus.
ro_ facilitate an understanding of the relationship between the various
init processes involved in the over-all waste treatment process, the
former have been arranged in the approximate order in which they might
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occur in a composite waste treatment flow chart in Figure 20. A similar
chart for sludge solids handling is presented in Figure 21.
sPECIAL_OPERATIONAL_ASPECTS_gF_CONTROL_TECHNOLOGY_
The nature of the treatment scheme proposed herein, coupled with certain
basic characteristics of the industry itself, calls for special design
and operating techniques in order to achieve satisfactory waste control.
The factors involved are discussed briefly in the following paragraphs.
industry employs many batch operations which tend to produce waste
of variable character and quantity. £s a consequence, there is often a
need for some way of obtaining a more uniform waste stream from the
standpoints of both composition and flow. Traditionally this has been
done by installing mixed equalization tanks through which the wastes
pass prior to being subjected to the principal treatment. However,
these units often present operating problems of their own. For example:
1. If the waste is not at biostatic concentrations when it reaches the
treatment plant, some bacterial growth will occur in the equalization
unit producing solids and tending to reduce the oxidation potential of
the system to ineffective levels with accompanying odors and nuisance
status.
2. It is necessary to provide a minimum cf 0.8 kw/cum (40 hp/1000 gal)
to be sure that the wastes in the equalization tank are completely mixed
and that sedimentation will not occur.
On the other hand, if an equalization unit is not provided, unit
operations and processes which are regulated by flow arid concentration
will be adversely affected. In minimizing or eliminating the adverse
effects of influent surges, the following should be considered:
1. Installation of clarification units which can be kept uniformly over
U m (12 feet) side water depth. Deep units are much less subject to
upsets by variations in surface loading than are shallower units of 3 m
(10 ft) or less.
2. If a completely mixed first stage activated sludge bioconversion
system is to be employed it should be understood that the effluent
quality will vary with the influent strength surges. Effluent quality
variations can be handled either by equalization, or by providing a
second activated sludge stage of the plug flow type. Since the energy
per unit/volume requirements for either option are roughly comparable,
the latter procedure is generally the most cost effective means of
dealing with this problem.
If carbon adsorption is to be employed instead of bioconversion, an
equalized feed stream will be necessary. Regardless of other
considerations, an upstream system capacitance must be provided if
maximum efficiency is to be obtained from the treatment.. Wnenever the
waste entering a coagulation and sedimentation unit tends to be highly
biodegradable, troubles with gasification in high solids systems may be
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tAW
VASTE'
EQUALIZA-
TION
COMPOSITE FLOWSHEET
WASTE TREATMENT
SOAP & DETERGENT INDUSTRY
TO REGENERATION
BRINE
FROM
REGENERATION
OIL & GREASE
REMOVAL
COAGULATION
SEDIMENTATION
SLUDGE &
OIL OUT
a
D
_l
to
CARBON
ADSORPTION
1
REVERSE
OSMOSIS
ION
EXCHANGE
FINAL
EFFLUENT
EFFLUENT
BIOCONVERSION
SLUDGE-RECYCLE
GREASE & OIL RECOVERY
SLUDGE CONDITIONING
AND
DISPOSAL
SAND OR
MIXED MEDIA
FILTRATION
UJ
FIGURE 20
-------
SLUDGE SOLIDS HANDLING
SOAP & DETERGENT INDUSTRY
SLUDGE FROM OILY
WATER TREATER
SLUDGE FROM
COAGULATION & SEDIMENTATION
OVERFLOW TO
PROCESS
WASTE SLUDGE
FROM BIOCONVERSIO
SYSTEM
THICKENING
OVERFLOW TO
PROCESS
THICKENING
> TO LAGOON
DEWATERING
VACUUM FILTER
OR CENTRIFUGE
OVERFLOW TO
PROCESS
HEAT
TREATMEN"
LAGOON ,
DISPOSAL
CAKE TO INCINERATION
OR GROUND DISPOSAL
GROUND
DISPOSAL
ASH TO LANDFILL
OR GROUND DISPOSAL
INCINERATION
91
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anticipated if neutral pH values are employed for coagulation.
Therefore, it is necessary to evaluate the residence or holdup of solids
that can be employed, prior to deciding upon a treatment system. Plant
shutdown for turnaround or under emergency conditions, particularly if
operations cease for more than two to three days, can result in a
diminution in the effectiveness of bioconversion systems on startup.
Under such circumstances, the advantages of having an equalization unit
of substantial size ahead of the bioconversion unit become apparent.
During turnaround, the equalization unit may be drained and cleaned,
thereby providing the food materials necessary to sustain the resident
biota in the bioconversion portion of the system. If this is not
possible, provision should be made for the discharge of stored
concentrated waste to the bioconversion unit during plant shutdown.
The equipment associated with the treatment steps proposed herein does
not have extraordinary maintenance requirements. Normal once per year
examination, along with routine maintenance, is the standard
requirement. Consideration should be given to providing unit by-passes
or the utilization of design concepts which will permit routine
maintenance without taking the unit out of service. It should be
generally possible to by-pass each individual unit without taking the
plant off the line or markedly changing the over-all operational
efficiency.
Waste treatment works must be well managed to avoid their becoming
public nuisances. If not handled properly, lagoons, the incineration of
sludge or the regeneration of carbon may generate objectionable odors.
This problem may be eliminated or controlled by proper location of the
units and the use of gas emission control equipment. In the case of
lagoons, proper operation of the preceding waste treatment units is
essential.
Solid Waste Generation Associated with Treatment Technology
Depending on the precise nature of the over-all waste stream, solid
waste may orginate at any one of several points in the waste treatment
process. Please refer to the composite waste treatment flow sheet. The
principal sources of solid waste are :
1. Sludge from the under flow of a gravity type oily water treater.
This sludge would normally be combined with other waste solids from the
process.
2. Sludge withdrawn from the coagulation and sedimentation unit and
combined with other waste sludges or processed separately.
3. Waste sludge which is normally generated in a bioconversion facility
although the units can be designed to approach virtual steady state
between new sludge production and the loss of resident sludge over the
weir and through endogenous respiration.
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Process sludges are treated by ore or mere of the methods outlined in
Figure 21. In rough chronological order, steps leading to the ultimate
disposal or sludge include the following:
1. As a first step, the sludge is thickened in a gravity thickener or a
centrifuaal device. In either case, effluent solid concentrations
varying from 3 percent to 10 percent may be anticipated. The difference
arises from the substantial differences in the characteristics of the
sludges.
2. After thickening, biological sludges may be treated to reduce
moisture content of the ultimate cake, The sludge is then subjected to
heat and pressure to reduce the size and complexity of the protein and
carbohydrate cellular material. This, in turn, releases bound water.
In some cases the sludge is discharged to a lagoon after this step.
3. In the next step, the sludges are dewatered, either on a vacuum
filter or in a solid bowl centrifuge. In some instances sludges will
have to be conditioned with either organic polymers or inorganic
polyelectrolytes prior to dewatering.
4. Following the dewatering step the sludge may be disposed of directly
or incinerated for the removal of virtually all of the residual organic
matter.
5. Following incineration, the ash, which constitutes from 5 percent to
10 percent of the initial mass, is disposed of as land fill.
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SECTION VIII
COST, ENERGY AND NON-fcATER QUALITY ASPECTS
There are fewer than a dozen plants associated with the soap and
detergent manufacturing industry which are point source dischargers into
navigable waters. Of these plants, only one has a complete
primary- secondary treatment plant comparable to those found in a good
municipal sewage treatment system. There are several aerated and
non-aerated lagoons which experience varying degrees of success in their
ability to reduce the incoming load to acceptable levels.
Because of the highly variable nature of the wastes which makes indi-
vidual treatment prohibitively expensive, most small and medium-size
plants will continue their current practice of sending their wastes to
municipal or regional systems. For this reason emphasis in this section
has been placed on in-plant controls rather then end-of-pipe treatment.
INZPLANT_CONTROL
There are essentially three sources of in-plant contaminants of the
waste water effluent streams. They are:
1. Impurities removed from raw materials
2. By-products or degradation products made
in the process
3. Very dilute product (in aqueous solution)
resulting from leaks and spills and the
clean out of equipment.
These are discussed in the succeeding paragraphs.
TABLE4
______
(gal/ 1000 Ib Product Produced)
(liters/1 19kg Product Produced)
Batch Kettle Soap 25 - 2345
Fat Splitting 203 - 23,200
Soap Via Fatty Acid Neutralization 31 - 1750
Glycerine Concentration 80 - 120,000
Glycerine Distillation 40 - 65,000
Bar Soap 9 _ 2300
97
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Oleum Sulfonation 12-90
Air/303 Sulfonation 1 - 240
Chlorosulfonic Acid Sulfonation 184 - 330
Neutralization 2 - 1100
Spray Dried Detergents 14 - 228
Liquid Detergents 75 - 185
Drum Dried Detergents 265 - 400
Detergent Bars & Cakes circa 25
Impurities Removal
There are two main sources of impurities which concern the manufacturers
of soaps and detergents. They are the light ends and color bodies in
the fats and oils used in the manufacture of soap, and the light ends
(usually low molecular weight fatty acids) removed in the flashing
and/or distillation of fatty acid produced from the fat splitting
process. In both cases the processes having high effluent loadings
employ barometric condensers. Replacement of barometrics by surface
condensers would appreciably reduce the amount of contamination
(approximately 80 percent) and, cf course, all but eliminate the entire
hydraulic loading. The capital cost of this replacement would amount to
approximately $2,00-$3,00/1000 Ib annual capacity of fatty acid in a
plant capable of making 100 million pounds per year having other capital
cost about $60-$70/1000 Ib of annual capacity. This, however, is not
the only way in which the effluent problem could oe minimized. An
alternative is to install an extractive step ahead of the barometric leg
where the light ends are picked up in an oil film to be later distilled
for the recovery of the valuable low molecular weight acids. An
installation of this type has been proven successful commercially. It
has a two year payout. An initial capital investment of approximately
$7-9/1000 Ib annual capacity of fatty acid produced would be required
for a 20 million Ib per year plant. A reduction in raw waste loadings
of approximately 85 percent would he attained.
Still another method of handling the problem is the installation of a
cooling tower with recirculation of condenser water, and employing a fat
skimmer. A periodic blowdown of the skimmer to sewer would dispose of
accumulated solubles, and the fat recovered would assist in the payout.
The cost for such an installation would be approximately $10-12/1000 Ib
of annual capacity for a 40 million Ib per year plant. Reduction of raw
waste loadings of approximately 75 percent would be anticipated.
Although not strictly an impurity, glycerine is carried overhead into
the barometric condenser water in the process of concentrating and
subsequently distilling the product out of dilute feeds. It is
98
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estimated that the cost of replacing the barometric legs with surface
condensers and appropriate vacuum equipment would amount to about
$21/1000 Ib annual capacity of glycerine and would reduce raw waste
loads by about 90 percent. This compares with a total cost of around
$40/1000 Ib annual capacity for installation of concentrators utilizing
barometric condensers. The payout for the surface condenser
installation (based on the additional product recovered) is around 10+
years. These estimates apply to a plant having a 10 million Ib per year
glycerine capacity.
Unfortunately, installation of a recirculating cooling water system
would have no effect upon the effluent loadings in this case since
glycerine is soluble in water in all proportions and recirculation would
only result in higher concentrations in lower volumes of water. This
could be offset by operating the cooling tower as a biological tower to
reduce organics.
BY-Product/Degradatigni Product Control
The dark colored soap (nigra) recovered from batch kettle soap making
can in some instances constitute a disposal problem. In the larger,
more integrated plants there is usually a market for the material (e.g.
pet soap) so that the disposal of the material is not a total liability.
Where this is not the case a modest investment would need to be made for
an accumulator tank where these materials could be acidulated to break
the soap, the fats being recovered and sold and the balance of the
aqueous layer being sent to disposal. An investment of about $2 -
$4/1000 Ib annual capacity of soap would be needed for this operation.
This is not an inconsiderable amount when related to an already fully
amortized older plant, but it would result in about 75 - 80 percent
reduction in raw waste load. If the fat is recovered, an ultimate
payout could be realized.
Degradation of product occurs most abundantly in the sulfonation
processes, particularly in the start up of an air-sulfur trioxide unit.
In large integrated plants this causes only minor problems since they
can often work off the relatively small amount by blending it into a
large volume material. The small scale custom sulfonator is the one of
concern. He has no economic alternative but disposal to sewer. Use of
a batch countercurrent process with improved agitation can give improved
heat transfer as well as increased contact of reactants. This can be
achieved with an almost undiscernible cost. In this case, the added
capital cost would amount to about $2. 20/million kg (Si/million Ib) of
annual capacity. Utilities consumption would increase less than 10
^percent from utilization of a recycling loop for the neutralized
sulfonic acid product stream.
PJllJ^g-P£g^ygt_From_Cleanouts^ Leaks £ Spills
Liquid detergent manufacture at present accounts for one of the higher
waste water effluent loadings in the industry. This is related to the
need to clean out the mixing tanks and filling lines thoroughly when
making a product change in the filling operation. If steam or air
99
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(rather than water) were used to blow the lines clean, the product could
be directly be reused or in the case of steam the more concentrated
solutions could be stored and either reused or disposed of more easily.
The cost to the larger highly integrated plants (50 million Ib per year
with a capital cost of $25-30/1000 Ib of annual capacity) would amount
to about $2 - $3/1000 Ib annual capacity of anhydrous product produced.
Resulting raw waste loads reduction on the order of 50 percent or
greater should be realized.
Additional major sources of dilute product streams are detergent spray
towers' air scrubbers and tower clean -outs. A suggested way in which
this could be reduced involves incorporating concentrated and dilute
scrubbing streams in series to chill ar.d scrub the exit gases from the
tower. The concentrated stream would be recycled to the crutcher and
the dilute stream used for make-up. The capital cost would amount to
about $1.00/1000 Ib annual capacity for spray towers capable of
producing 100 million Ib per year. This includes cooling facilities to
keep the scrubber water down to an effective chilling temperature. Raw
waste reduction should be approximately 65 percent.
END_OF_PIPE_TREATMENT
Waste water streams from soap and detergent processes are readily bio-
degradable, but they do not have uniform flows nor are their
concentrations constant. In most cases there are significant surges
having varying strengths of contaminants. This set of conditions is
very detrimental to the successful operation of a treatment system. For
this reason, small scale operators having intermittant streams of 10,000
- 50,000 gallons per day of waste water are almost without alternative
to utilization of municipal sewer systems.
Packaged, off the shelf units, at a cost approximating $600/1000
gal/day, could indeed handle the load for a small plant if it were
consistent in quality, concentration, and flow. None of these
conditions, however, describe the waste waters associated with
operations of the conventional small or large plant. An alternative
could be the installation of a large equalization basin, but it would be
prohibitively expensive for a small operation. Further, the typical
plant is usually located in a metropolitan area where the availability
of enough land poses an insurmountable problem.
In plants having daily flows of about 500,000 gallons, the capital cost
for end of the pipe treatment can be expected to run around $2,000,000
with an operating cost approaching $900/million gallons. Best
practicable control treatment currently available would most likely
include chemical precipitation and equalization followed by an activated
sludge unit and final clarification.
Best available technology economically achievable would incorporate a
final polishing operation, such as mixed media filtration or carbon
absorption, or a second stage activated sludge unit with plug flow
operation.
100
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Table 5
Cost and Energy Requirements Associated
With Various Treatment Methods
Treatment Procedure
Capital
Costs
Operational
Power Requirements
Oil & Grease
Removal
Hand skimmed
tanks $26-79/1000 1
($100-300/1000 gal.)
Mechanically
cleaned tanks $13-18/1000 1
($50-70/1000 gal.)
Mixed media
filtration
Flotation
Carbon
adsorption
$21-66/1000 1
($80-250/1000 gal.)
$11-37/1000 1
($40-140/1000 gal.)
$26-210/1000 1
($100-800/1000 gal.)
$5.00/day
None
$0.008-0.026/1000 1 0.19-0.57 kw/1000 cu in/day
($0.03-0.10/1000 gal.) 1-3 hp mgd
$0.032-0.105/1000 1
(0.12-0.25/1000 gal.)
1.52-2.85 kw/1000 cu m/day
8-15 hp/mgd
$0.03-0.11/1000 1 1.14-2.85 kw/1000 cu m/day
($0.12-0.40/1000 gal.) 6-15 hp/mgd
$0.22-0.66/kg oil
($0.10-0.30/lb oil)
0.95-1.9 kw/1000 cu m/day
5-10 hp/mgd
-------
Table 5
(cont'd)
Treatment Procedure
Costs
Power Requirements
Capital
Operational
Carbon Adsorption
System
Fixed carbon
in column $26-79/1000 1
($100-300/1000 gal.)
Powdered car-
bon fed prior
to coagulation
& sedimentation
void
$6-26/1000 1
($25-100/1000 gal.)
Final
Clarification $13-40/1000 1
($50-150/1000 gal.)
Effluent
Filtration
$21-69/1000 1
($80-260/1000 gal.)
Reverse Osmosis
Systems
T79-158/1000 1
($300-600/1000 gal.)
$0,
($0,
04-0.132/1000 1
15-0.50/1000 gal.)
0.95-1.9 kw/1000 cu m/day
5-10 hp/mgd
$0,
($0,
$0,
($0,
$0,
($0,
$0,
($0.
04-0.132/1000 1
15-0.50/1000 gal.)
008-0.019/1000 1
03-0.07/1000 gal.)
013-0.040/1000 1
05-0.15/1000 gal.)
079-0.269/1000 1
30-1.00/1000 gal.)
0.95-2.85 kw/1000 cu m/day
5-15 hp/mgd
0.19-0.57 kw/1000 cu m/day
1-3 hp/mgd
0.95-1.9 kw/1000 cu m/day
5-10hp/mgd
190 kw/1000 cu m/day
1000 hp/mgd
-------
Table 5 (cont'd)
Treatment Procedure Costs Power Requirements
Capital Operational
Suspended Solids
Removaf
Coagulation &
sedimentation $13-40/1000 1 $0.013-0.024/1000 1 0.19-0.57 kw/cu in/day
($50-150/1000 gal.) ($0.05-0.09/1000;gal.) 1-3 hp/mgd
Chemical
addition $0.003-0.013/1000 1
($0.01-0.05/1000 gal.) Fractional mgd
Mixed Media
o Filtration & Flotation - See Oil & Grease Removal
OJ
Bioconversion.:
Systems
Activated
sludge $29-73/1000 1 $0.013-0.039/1000 1 19-95 kw/1000 cu in/day
($110-275/1000 gal.) ($0.05-0.15/1000 gal.) 100-500 hp/mgd
Aerated Lagoons
$28-53/1000 1 $0.016-0.029/1000 I 19-95 kw/1000 cu m/day
($70-2000/1000 gal.) ($0.04-0.12/1000 gal.) 100-500 hp/mgd
Extended
aeration $21-79/1000 1 $0.013-0.053/1000 1 19-95 kw/1000 cu m/day
($80-300/1000 gal.) ($0.05-0.20/1000 gal.) 100-500 hp/mgd
-------
Table 5 (cont'd)
-Power cost taken at $0.01 KWH
-Attendance @ $5.00/hour
-Manufacturer data used for power requirements ,,,.,-,« >.OT-,\ «- u
-Plant sizes are generally across 0.01-0.19 kw/1000 cu m/day (0.1-1.0 hGD) to show
cost variation and economy of scale.
-------
ENERGY PEQUIREMENTS
With the introduction of surface condensers to replace the barometrics,
utility costs (including power) will increase. Generally, in those
processes requiring capital modification because of guideline
recommendations, the utility costs will rise an average 220/1000 Ib of
product manufactured. About 70 of this is due to direct power needs,
the rest being for steam, cooling water, etc.
As might be expected, the processes impacted the most are glycerine
concentration and distillation which amounts to about $7,80/1000 Ib.
NON-WATER_QUALITY_ASPECTS
There is very little non-waterborne waste generated in the production of
soaps and detergents. Almost all (99+ percent) of the raw materials
entering the soap and detergent processes end up as packaged products
for sale to the household or industrial consumer. Modest amounts of
solid wastes end up in sanitary landfill operations.
In the operation of dry filling lines there are infrequent problems with
the mechanical equipment that result in damaged cartons. This same
problem applies with many of the operations, including warehousing.
Wherever possible, the product is recycled back into the manufacturing
process unless it becomes excessively contaminated. At most, one would
expect several hundred pounds per day of solid wastes being sent to a
sanitary landfill for disposal from a large plant.
During spray drying tower cleanouts, there often will be caked, charred
material unsuitable for recycle. This would amount to about 1000 Ib per
week from a very large plant; again, this material would be sent to a
sanitary landfill.
Sludge from waste water treatment will also be an input into sanitary
landfill operations. One system in operation pumps the sludge from the
biotreater into the chemical treater where it precipitates with the
addition of lime. The settled precipitate is pumped to a settling basin
where the sludge builds up to a depth worthy of disposal, whereupon the
"solids" are then taken to the landfill.
Conversion of air contamination problems into waste water problems is on
the increase in the soap and detergent industry. soap dust from bar
soap manufacture, and fines in exit air from the detergent spray tower
are being dissolved in scrubber water to be ultimately treated in sewage
systems. This is an ideal way to maximize the disposal alternatives.
The products are biodegradable and readily handled in already existent
standard treatment facilities.
IMPLEMENTATION_OF_TREATMENT_PLANS
The equipment required for implementing the waste treatments discussed
in the preceding sections of this report are available as off-the-shelf
items or they may be found in manufacturers' catalogs. In the present
105
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economy the construction manpower is generally available, although short
term local variations in availability are to be expecred. However,
virtually all of the work required would be carried out by the general
contractor normally involved in the construction of sewage and
industrial waste treatment works.
Depending upon the waste treatment employed and the precise unit process
under consideration, the land requirements will vary from as little as
one-half acre to as much as three or four acres. It is likely that, for
the industry as a whole, a good mean land requirement would be of the
order of 0.4 to 0.8 ha (one to two acres).
The basic costs and relative efficiencies of the waste treatment
processes outlined in the composite waste treatment flow chart have been
summarized in Table 5. The capital and operating costs were derived
from actual plants which have been constructed within the past few
years. The higher range costs and capital are applicable to waste water
flows of 50,000 - 100,000 gallons per day. The lower end of the range
is applicable to volumes of 2 - 3 million gallons per day. The data in
the table were adjusted upward and expressed in terms of 1972 dollars.
Regarding operational costs, the figures cited are direct costs only.
They do not include any administrative, overhead, fringe benefits or
directly charged laboratory support. If these costs were to be
included, the total would be roughly double.
Sludge conditioning and disposal costs are highly variable, depending
upon the nature of the sludge and the procedures followed. The cost
brackets for the sequences outlined in Figure 20 are shown in Table 6.
It is assumed that land is available for lagoon and landfill disposal of
sludge and ash.
106
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Table 6
Cost of Sludge Conditioning and Disposal Operations
Procedure
Costs
Power Requirements
1. Thickening-
influent at
5000 mg
2. Lagooning
3. Heat Treatment
Capital
Operational
$1800-6400/metric ton
($2000-7000/ton)
$1.60-6.40/metric ton
($1.80-7.00/ton)
Depends upon land cost entirely
$13,640-45,400/metric
($15,000-50,000/ton)
ton $4.50-13.60/metric ton
($5-15/ton)
Fractional/tpd
181-454 hp/mtpd
200-500 hp/tpd
Dewatering
4.
Vacuum Filtration $103-297/m2
(95-275/sq ft)
5. Centrifugation
6. Incineration
$455-909/mtpd
($500-1000/tpd)
$136,400-681,800/mtpd
($150,000-750,000/tpd)
$7.30-31.80/metric ton
($8-35/ton)
$4.55-22.70/metric ton
($5-25/ton)
$4,55r22.70/metric ton
($15-50/ton)
22.7-68.2 hp/mtpd
22-75 hp/tpd
45.5-90.9 hp/mtpd
50-100 hp/tpd
182-273 hp/mtpd
200-300 hp/tpd
17.2-68.9 1 of
fuel oil/metric
ton (5-20 gal.
fuel oil/ton)
-------
SECTION IX
BEST PRACTICABLE CONTROL TECHNOLOGY
CURRENTLY AVAILABLE
Introduction
One of the first steps in the development of guidelines was the
determination of raw waste loadings in the waste water flows for each
subcategory in terms of kg/kkg (Ib of pollutant/1000 Ib) of anhydrous
product produced in that subcategory. The raw waste loading to be
expected from the best practicable technology was established and the
guidelines values defined as appropriate reduction of the raw waste
load, e.g., reasonable expectancy of any treatment plant having a
biological secondary treatment process to attain 90 percent reduction of
BOD 5.
Wherever appropriate, attention was given to in-plant controls to
minimize the raw waste load.
Several soap and detergent processes have almost a negligible discharge
in a number of manufacturing plants practicing those processes. Best
practicable control technology currently available guidelines give each
of these processes a very small but finite effluent allowance because of
one or more of the following reasons:
1. The product in the effluent stream is so degraded it would
be unsuitable for incorporation in the final product and must
thus be disposed of.
2. The waste water source is so dilute as to require undue amounts
of heat energy to recover the dissolved solids content.
3. The material in the waste water is quite biodegradable; there-
fore, is readily handled by the receiving treatment plant.
In those categories where the guidelines have been set particularly low,
the permit writer should be alert to the occasional need ro make spot
increases in these limits. Upsets ard mechanical problems requiring
cleanouts may crop up, rare though they may be. This will be
particularly critical for small plants (under $500,000 in gross
proceeds). The larger integrated plants have sufficient flexibility in
their ability to recycle the contents of waste streams to minimize their
iced for spot increases.
In a few processes there are some relatively heavy discharges of salt
and sodium sulfate. No limit has been established for these very low
toxicity materials since 1) they will be highly diluted by other process
effluents before becoming a point discharge and 2) the permit writer
will undoubtedly want to evaluate the background levels in the receiving
waters and determine what levels, if any, should be established.
^o maximum delta temperature was established since the differential
Detween inlet and outlet process water temperatures is quite modest, at
109
-------
most around 17°C (30°F), and much of the heat would be dissipated in the
waste treatment process.
The interrelationship of air and water pollution problems became quite
apparent in this study. Increasingly stringent air emission standards
have set performance requirements beyond the ability of dry recovery
systems available on detergent spray towers. Wet scrubbers have been
employed which now allow the air effluent to meet those standards, but
result in a substantial water flew and a correspondingly higher BOD5
loading.
In every instance in the following guidelines, the pH of the point
source discharge is required to be between 6.0 and 9.0.
§QAP_MANUFACTURING
101_-_SQAP_MANUFACTURE BY KETTLE BOILING
General
This ancient art has been carefully scrutinized by all of its
practitioners to minimize cost and the avoidable less of marketable
products where the installed capital permits. Even in the area of very
high quality soaps there still appears to be a preference for this well
established process.
There are essentially two main streams carrying away waste from this
source (in actual practice there may be more subsidiary sources). They
are typified by the blocks indicated in the simplified flow diagram
given below:
Neat Soap
Solid
Waste
Liquid Waste
WASTEWATER SOURCES IN SOAP MANUFACTURE
FIGURE 22
The liquid waste from fat pretreatment will normally be a fat in water
emulsion of modest BOD5, with perhaps some clay and other organics.
However, the stream from nigre processing, often just a purge, will be
110
-------
very rich/in BOD5 and contain some sodium chloride and sodium sulfate.
Some soap manufacturers do net, at present, completely process their
nigre but run it directly to sewer. This is a point, for some, to
improve in effluent control.
Raw Waste Loading
The following are the expected thirty day average raw waste loadings
which would be entering a waste treatment plant:
BOD5 - 6 kg /kkg (6 lb/1000 Ib) anhydrous soap
COD - 10 kg /kkg (10 lb/10001b) anhydrous soap
Suspended Solids - 4 kg /kkg (H lb/1000 Ib) anhydrous
soap
Oil and Grease - 0.9 kg /kkg (0.9 lb/1000 Ib)
anhydrous soap
Best Practicable Control Technology,CurrentlY_Ayailable_Guidelj_neR
On a thirty day average basis the following parameter values are
recommended:
BOD5 - 0.60 kg/kkg (0.60 lb/1000 Ib) anhydrous soap
COD - 1.50 kg/kkg (1.50 lb/1000 Ib) anhydrous soap
Suspended Solids - O.40 kg/kkg (0.40 lb/1000 Ib)
anhydrous soap
Oil and Grease - 0.10 kg/kkg (0.10 lb/1000 Ib)
anhydrous soap
pH 6.0-9.0
In the event of upset, startup or shutdown procedure, a value of three
times that indicated above should be considered, provided that over any
given thirty day period the recommended average is maintained.
Best Pracrticable_Control_Technology__Currently Available
In many soap plants there are no access points in the floor to the
sewer. This makes good housekeeping unavoidable. All leaks and spills
are promptly attended to and recycled within the process.
The guidelines limitations can be attained by the production (and
marketing) of low grade soap from the nigre, recovery of fats from
acidulated sewer lyes and nigre, and secondary (biological) treatment of
the resulting waste.
Ill
-------
Rationale and Assumptions
Fat saponification is carried out counter-currently where the aqueous
caustic stream is exhausted in a final reaction with fresh fat. At the
other end of the process the nearly fully saponified fat is completely
reacted by coming into contact with fresh caustic. Salt recycle becomes
automatic in that energy required to concentrate the glycerine stream
automatically concentrates the salt. Filtration of the evaporator
product provides the recycle salt. There is still a substantial amount
of salt that goes to the sewer via the bleed of the nigre.
Phase relationships of electrolyte, soap and caustic content largely
govern their concentration and use to maintain proper soap solubility.
Within these constraints good manufacturing management will minimize the
total constituents going to sewer.
At present, this process can be brought close to no discharge only at
the expense of the smaller soap manufacturers who do not exhaust their
nigre. The recommended settling and acidulation tank will go a long way
toward attaining this goal.
Most kettle boil soap making equipment is several decades old and repre-
sents fully amortized capital. The soap market is not noted for its
dynamic expansion.
102 - FATTY ACID MANUFACTURE BY FAT SPLITTING
General
The waste water effluents for disposal come from essentially three
sources; pretreatment of the fat, light ends emitted from the fat
splitter and the fat still, and the water solubles left in the
acidulated still bottoms after the recycleable fats are removed and
recovered.
The light ends mentioned above are found in the condensate from the
barometric condenser and include short chain fatty acids and
unsaponifiables. One of the minor contaminants in the stream coming
from the still bottoms is the catalyst. It can be the sulfate salt of
zinc, or other alkaline earth metals.
A simplified schematic is given for the
approximate location of waste water streams.
process to indicate the
Fats] \
Light
Ends
Fat
Splitter
*
Glycerine
to
Recovery
*
->4 Still I
i '
\
— ) —
iBottomsl )
f
Fatty Acid
to Market
Acidulation
& Settling
To
Strea
/
ving
m
\
Water Solubles
& Metals Salts
J,
| Fats Recovery!
FAT SPLITTING
FIGURE 23
112
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The following raw waste loading can be expected:
BOD5 - 12 kg /kkg (12 lb/1000 Ib) anhydrous acid
COD - 22 kg /kkg (22 lb/1000 Ib) anhydrous acid
Suspended Solids - 22 kg /kkg (22 lb/1000 Ib) anhydrous
acid
Oil and Grease - 2.5 kg /kkg (22 lb/1000 Ib) anhydrous
acid
Included in this loading are waste water flows from: fats treatment,
fats splitting, fatty acid distillation and still bottoms disposal.
Best_Practicable_CQritrQl_ Technology Currently^Available_Guidelines
On a thirty day average, the following parameter levels are recommended:
BOD5 - 1.20 kg/kkg (1.20 lb/1000 Ib) anhydrous acid
COD - 3.30 kg/kkg (3.30 lb/1000 Ib) anhydrous acid
Suspended Solids - 2.20 kg / kkg (2.20 lb/1000 Ib)
anhydrous acid
Oil and Grease - 0.30 kg/1000 Ig (0.30 lb/1000 Ib) anhydrous
acid
pH 6.0-9.0
No additional provision need be made for startup, shutdown or upsets.
Allowance should be made for a twofold loading over a 24 hour period,
providing that during a thirty day period, which includes this day of
high loading, the recommended average is maintained.
B§st_P£acticable_CgrvtrQl_Techngloqy Currently Available
Essential to the proper performance of the plant is the incorporation of
appropriate fat traps. Indicative of the technology involved is the
flow chart of a condenser/recovery unit which could handle the load.
Note that the only effluent is blowdown of the fat settler which handles
cooling tower waters.
Due to the high temperatures maintained in the fat splitter, fat
solubility and reaction rate are high so that 99 percent hydrolysis can
be expected. This makes separation of the condensates a relatively
simple problem, well within the engineering capabilities of the
industry. As noted in the above discussion, it is reasonable to expect
that the only materials to be disposed of are light ends and bottoms.
Rationale^and Assumptions
113
-------
Still ) Fatty Acid
Vapors
(Light Ends)
.
Barometric
Condenser
A
Recycle
Water
V
— 7
Cooling
Tower
\
/
Fat Settler
I
Recovered
Fat
s
V
>
/
Blowdown to
Stream
FATS RECOVERY SYSTEM
FIGURE 24
114
-------
A fats recovery unit for treating fatty acid still bottoms will help
minimize loadings of effluent. This equipment plus biological secondary
treatment will bring the loadings down to the guidelines level.
I02_^_FATTY_ACID_HYDROGENATION
General
As an example of the depth to which some technological studies have been
conducted, the details of fatty acid hydrogenation processing are
presented. Due to the advanced state of the art, guidelines recommended
are to cover all levels.
Technology forijAll Levels
Hydrogenation of fatty acids intended for soap manufacture is regarded
as an additive effluent loading to the fat splitting operation.
The principal raw materials for the manufacture of fatty acids used in
soap making are coco and tallow fats. These are generally used in the
ratio of about 80 percent tallow fatty acids to 20 percent coco fatty
acids in soap making.
This blend contains in the order of 15 percent of the mono-unsaturated
oleic acid and around 3-4 percent of the doubly unsaturated linoleic
acid. There is very little of the triply unsaturated linolenic acid.
20 percent unsaturated fatty acids in soap is often excessive,
consequently the tallow portion of the fatty acids going into soap
manufacture are partially hydrogenated. This is particularly necessary
since tallow contains up to 50 percent cleic acid esters and as much as
3 percent linoleic esters.
The usual process of making fatty acids and the hydrogenation of them is
given in the schematic flow diagram for the fatty acid manufacture
subcategory. The hydrogenation process is usually carried out batch
wise, particularly for fatty acids destined for soap making.
The hydrogen source for this process depends upon plant location. When
near a petroleum refinery the hydrogen is often available from cracking
operations and subsequently requires purification. Hydrogen is also
available from electrolytic cells dedicated to electrolysis of salt for
production of sodium and chlorine.
Another common source of hydrogen is that from the dehydrogenation of
isopropyl alcohol to make acetone. Whatever the source of hydrogen
there will usually be some alkane impurities that will build up in the
recycle use of hydrogen; consequently, a bleed is necessary and is
usually disposed of by burning. This disposition carries no water
effluent and consequently is disregarded in the guidelines.
The hydrogenation process requires a catalyst. There are two well-known
catalyst systems. One involves the deposition of nickel as nickel
formate onto a pumice or kiesselguhr or a synthetic product such as
115
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Celite. The other commonly used catalyst is Raney-nickel. Both
catalysts are usually suspended in the liquid to be hydrogenated and
subsequently filtered out. when Raney-nickel is used, the spent
catalyst is often recovered and returned to the manufacturer for
reprocessing.
Complete saturation of the fatty acids is not desirable since a modest
amount of cross linking by oxidation helps to make a firm soap and gives
the bar good feel or hand. Though not strictly true, the hydrogenation
of coco and tallow fatty acids is described as if the same in nature.
Hydrogenation is usually carried out with the catalyst suspended in the
liquid fatty acids in a batch process heated to a temperature of
approximately 175 - 200 C (347 - 392 F) as the hydrogen passes through
the reactor. When the degree of saturation desired is achieved (as
measured by iodine number) the reaction . is terminated. Recovered
hydrogen is removed and sent back to storage via a booster system.
During the hydrogenation process a number of side reactions occur, some
of which cause significant waste water effluent contamination.
Isomerization of the double bond along the chain does not cause any
difficulty. However, occasional chain scission occurs, resulting in the
formation of short chain length olefins and short chain fatty acids not
desirable in the soap making process. As a result of the fatty acid
pre-heating prior to hydrogenation there is a tendency for some
oxidative cross linking to occur, resulting in a modest amount of
polymerized fatty acids. Storage of the fatty acids at high
temperatures also accelerates this polymerization reaction. Some of
these undesirable reactions result in added waste water contamination.
The same raw waste loadings can be expected for all levels of
technology.
Raw Waste Loadings^-^All Leyelg
The following raw waste loadings are expected:
BOD5 - 1.5 kg/kkg (1.5 lb/1000 Ib) anhydrous acid
COD - 2.5 kg/kkg (2.5 lb/1000 Ib) anhydrous acid
Suspended Solids - 1.0 kg/kkg (1.0 lb/1000 Ib)
anhydrous acid
Oil and Grease- 1.0 kg/kkg (1.0 lb/1000 Ib)
anhydrous acid
On a thirty day average basis, the following guidelines are recommended:
BOD5 - 0.15 kg/kkg (0.15 lb/1000 Ib) anhydrous acid
COD - 0.37 kg/kkg (0.37 lb/1000 Ib) anhydrous acid
116
-------
Suspended Solids - 0.10 kg/kkg (0.10 lb/1000 Ib)
anhydrous acid
Oil and Grease - 0.10 kg/kkg (0.10 lb/1000 Ib)
anhydrous acid
pH - 6.0 - 9.0
There is little or no need for an additional upset allowance.
Rat ion alemand_ Assumptions
It may be noted that hydrogenation steps in the manufacture of fatty
acids from fats is considered as a supplemental allowance in view of the
occasional use of this process in the general manufacturing system for
soap manufacture. The levels of effluents suggested and their nature
have been outlined above, based upon a reasonable allowance by careful
practice of the art of hydrogenation and by a careful control and
maximum recovery of effluent streams. There is no particular
discernible addition in the way of capital requirements or utility and
power requirements that would be more than marginal for these effluent
limitations guidelines requirements.
lQ3_-_gOAP_FROM FATTY ACID NEUTRALIZATION
General
This method of neat soap manufacture is a clean process. The major
starting material, fatty acid, has already been subjeered to a severe
refining step. During the oil splitting process the volatile acids and
color bodies have been removed.
Neutralization is frequently carried out with soda ash, which results in
the evolution of carbon dioxide. In large installations, the
neutralization may be a continuous process. Batch operations utilizing
stoichiometric amounts of fatty acids and alkalis may be employed.
Raw Waste Loading
The following raw waste loading can be expected:
BOD5 - 0.1 kg /kkg (0.1 lb/1000 Ib) anhydrous soap
COD - 0.25 kg /kkg (0.25 lb/1000 Ib) anhydrous soap
Suspended Solids - 0.2 kg /kkg (0.2 lb/1000 Ib)
anhydrous soap
Oil and Grease - 0.05 kg /kkg (0.05 lb/1000 Ib)
anhydrous soap
117
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Bes^Practicable Control Technology Currently Available Guidelines
On a thirty day average basis the following parameter limits are
recommended:
BOD5 - 0.01 kg /kkg (0.01 lb/1000 Ib) anhydrous soap
COD - 0.05 kg/kkg (0.05 lb/1000 Ib) anhydrous soap
Suspended Solids - 0.02 kg /kkg (0.02 lgs/1000 Ib)
anhydrous soap
Oil and Grease - 0.01 kg / kkg (0.01 lb/1000 Ib)
anhydrous soap
pH 6. 0 - 9.0
There is little or no need for an additional upset allowance.
Best Practicable Control Technology Currently Available
Secondary biological treatment will very adequately handle the effluent
from this process.
Rationale_and_
This process is carried out using stoichiometric quantities of all
reactants so that the entire content of the reactor is sent in total to
the next processing step; bar soap, soap flakes/chips, or liquid soap.
The product is neat soap at approximately 70 percent concentration.
Leaks from pump and other packing glands should be gathered and returned
to the process.
10U - GLYCERINE RECOVERY
General
The character of the waste water streams from glycerine recovery will be
determined by the source of the dilute streams which are concentrated.
There are two sources of dilute glycerine; one from the processing of
sweet water lyes of kettle boiling soap and the other from fat
splitting.
In the case of the soap making source, a stream which contains 8 - 15
percent glycerine, salt and miscellaneous organic matter is run to a
batch evaporator and concentrated to 60 - 80 percent. In glycerine
concentration the 80 percent product is removed as a bottoms product and
therefore contains all of the original impurities (less a lot of the
original salt), but in a much more concentrated form. At this point the
stream is either sold to a glycerine refiner or again batch handled in a
glycerine still where the product is taken overhead.
118
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The dilute glycerine stream from fat splitting can be varied
significantly in concentration. It all depends upon how the fat
splitter is operated. Glycerine is a bottoms product from the splitter.
A fairly concentrated glycerine can be obtained if the yield of fatty
acid is sacrificed or the production rate is diminished.
As the glycerine stream comes from the fat splitter, it is normally
flashed to atmospheric pressure, thereby gaining an immediately
increased concentration of product.
A simplified flow chart of the concentrating and distillation process is
as follows:
Condensate to Waste
To Soap
Manufacture
GLYCERINE CONCENTRATION
FIGURE 25
Raw Waste Loading
The glycerine concentration and glycerine distillation should be handled
separately. Quite often the glycerine which is concentrated to 60 or 80
percent is sold to another firm for further distillation to an assay of
98+ percent glycerine.
Raw waste characteristics are expected to average as follows:
Glycerine Concentration
BOD5 - 15 kg /kkg (15 lb/1000 Ib) anhydrous^glycerine
COD - 30 kg /kkg (30 lb/1000 Ib) anhydrous glycerine
Suspended Solids - 2 kg /kkg (2 lb/1000 Ib) anhydrous
glycerine
Oil and Grease - 1 kg/kkg (1 lb/1000 Ib) anhydrous
glycerine
Distillation
119
-------
BOD5 - 5 kg /kkg (5 lb/1000 Ib) anhydrous glycerine
COD - 10 kg /kkg (10 lb/1000 Ib) anhydrous glycerine
Suspended Solids - 2 kg /kkg (2 lb/1000 Ib)
anhydrous glycerine
Oil and Grease - 1 kg/kkg (1 lb/1000 Ib) anhydrous glycerine
S§st-P£a2ticable_Cgn.trol_TechnQlQgy Currently Available Guidelines
Separate guidelines should be established for the waste water effluents
for the glycerine concentration step and the final glycerine
distillation since, in many cases, these two operations are not carried
out at the same geographical location nor b'y the same manufacturer. In
the event both concentration and distillation are conducted at the same
location, the parameter values of each operation should be combined for
a final effluent allowance.
On a thirty day average basis, the following effluent guidelines are
recommended:
Gly. cer ine_Conc e n tr at i on
BOD5 - 1.50 kg /kkg (1.50 lb/1000 Ib) anhydrous glycerine
COD - 4.50 kg/1000 Ig (4.50 lb/1000 Ib) anhydrous glycerine
Suspended Solids - 0.20 kg/kkg (0.20 lb/1000 Ib)
anhydrous glycerine
Oil and Grease - 0.10 kg /kkg (0.10 lb/1000 Ib) anhydrous
glycerine
pH 6.0-9.0
Glycerine Distillation
BOD5 - 0.50 kg /kkg (0.50 lb/1000 Ib) anhydrous glycerine
COD - 1.50 kg /kkg (1.50 lb/1000 Ib) anhydrous glycerine
Suspended Solids - 0.20 kg / kkg (0.20 lb/1000 Ib)
anhydrous glycerine
Oil and Grease - 0.10 kg /kkg (0.10 lb/1000 Ib) anhydrous
glycerine
pH 6.0-9.0
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Little or no upset allowance should be allowed and it should not affect
the thirty day average for either glycerine concentration or
distillation.
Best Practicable Control Technology Currently Available
Much of the glycerine concentrating equipment in soap plants is fairly
old. It is operated in a batch manner and apparently the vapors carry a
fair amount of entrainment, as is evidenced by the amount of salt
carryover in the condensate. The long residence time in the
concentrators helps to build up glycerine polymers and degrades other
heavy ends leading to high BOD5 loadings in the resulting waste water
stream.
Where the barometric condenser is continued in use, the installation of
a biological cooling tower with the attendant recycle of barometric
water can materially reduce the raw waste load.
Rationalemand_Assumption
In almost all cases observed there has been a significant BOD5 loading
in the barometric condenser water, which is due to the glycerine
escaping the condensing system. Apparently this is not now regarded as
a worrisome economic loss; it does constitute a high biochemical
loading. The employment of more efficient condensers, eliminating the
barometric leg, is one way in which effluent loadings can be reduced.
Another method is the employment of column reflux in the glycerine
evaporators to reduce glycerine loss.
105_- SOAP FLAKES AND POWDERS
General
Neat soap is either chill roll, air or spray dried. In either case, the
waste water loading is minimal. There are occasional washdowns and
cleanups required, though rare.
Raw^Wagte Loading
The leaks, spills and pump gland cooling water will contribute the
following loadings:
BOD5 - 0.1 kg /kkg (0.1 lb/1000 Ib) anhydrous soap
COD - 0.3 kg /kkg (0.3 lb/1000 Ib) anhydrous soap
Suspended Solids - 0.1 kg /kkg (0.1 lb/1000 Ib)
anhydrous soap
Oil and Grease - 0.1 kg /kkg (0.1 lb/1000 Ib)
anhydrous soap
Best_Practicable Control Technology Currently Available Guidelines
121
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On a thirty day average basis, the parameter levels are recommended to
be:
BOD5 - 0.01 kg /kkg (0.01 lb/1000 Ib) anhydrous soap
COD - 0.05 kg /kkg (0.05 lb/1000 Ib) anhydrous soap
Suspended Solids - 0.01 kg /kkg (0.01 lb/1000 Ib) anhydrous soap
Oil and Grease - 0.01 kg /kkg (0.01 lb/1000 Ib) anhydrous soap
pH 6.0-9.0
The permit authority may find an occasional situation meriting a spot
increase above these values for unforeseen equipment washouts. An upset
allowance of one to two times the monthly average should be made.
££££_ Practicable_Contrgl_Technclpgy_Currentlv Available
Manufacture of flakes and powders has been optimized well to minimize
losses. The systems are maintained dry in normal practice, thereby no
continuous waste water is generated. Only where there is associated
soap reboil (to recover scrap soap) is there any appreciable amount of
effluent generated.
Incineration of scrap soap is one way in which effluents could be
reduced, where applicable and economically feasible. In any event,
biological secondary treatment will appropriately reduce the waste
loadings to acceptable levels.
General
Starting with neat soap (approximately 70 percent soap solution in
water) the processes for making bar soaps are quite varied. The major
differences occur in the drying technique. soaps in bar form will have
a final moisture content varying from 8 percent to over 15 percent,
depending upon the particular properites desired.
Depending upon the particular products made and processes employed,
situations encountered range from those with no waste water effluents of
any kind generated to those having several scrubber water effluents.
washouts may be a minor source of pollution, both in terms of effluent
volume and pollutant loadings.
Raw Waste Loading
The following waste water effluent concentrations are regarded as an
average expectation:
BODS - 3.4 kg /kkg (3.4 lb/1000 Ib) anhydrous soap
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COD - 5.7 kg /kkg (5.7 lb/1000 It) anhydrous soap
Suspended Solids - 5.8 kg/kkg (5.8 lb/1000 Ib) anhydrous soap
Oil and Grease - 0.4 kg/kkg (o.4 lb/1000 Ib) anhydrous
soap.
Best Practicable Control Technology Currently Available_Guidelines
On a thirty day average basis the following parameter values are
recommended:
BOD5 - 0.34 kg/kkg (0.34 lb/1000 Ib) anhydrous soap
COD - 0.85 kg/kkg (0.85 lb/1000 Ib) anhydrous soap
Suspended Solids - 0.58 kg/kkg (0.58 lb/1000 Ib)
anhydrous soap
Oil and Grease - 0.04 kg/kkg (0.04 lb/1000 Ib) anhydrous soap
pH 6.0-9.0
Little or no allowance for upset is required.
Best Practicable Control Technology Currently AYailable
There is concerted effort within the industry to minimize water use in
this particular operation. One of the unresolved questions is whether
air quality restrictions will force other "dry" operators to incorporate
scrubber systems for picking up elusive soap dust.
The levels specified in the guidelines are readily achievable by the
collection and recycle of soap dust (via dust collectors or scrubbers)
or by secondary biological treatment.
Rationa1e_and_Assumptions
Without much more detailed analysis of the bar soap making operation it
is very difficult to discern just how close to zero discharge all
processes could come without seriously jeopardizing the product
performance, hence the relatively broad allowances.
1_07_z_LI2UID_sgAP
General
Neat soap (approximately 70 percent soap and 30 percent water) is run
into a mixing tank to be blended with other ingredients, filtered if
123
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required and drummed. There may be need for an occasional equipment
washout and a frequent filter cleanout.
Constituents going into these blends are quite varied since their
functions range widely. This kind of business is close to custom
blending due to the high performance nature of many of their products.
Raw Waste Loading
On the basis of a thirty day average the following raw waste loadings
can be expected:
BOD5 - 0.1 kg/kkg (0.1 lb/1000 Ib) anhydrous soap
COD - 0.3 kg/kkg (0.3 lb/1000 Ib) anhydrous soap
Suspended solids - 0.1 kg/kkg (0.1 lb/1000 Ib) anhydrous soap
Oil and Grease - 0.1 kg/kkg (0.1 lb/1000 Ib) anhydrous soap
Best Practicable Control Technology Currently Available Guidelines
As a thirty day average the following effluent parameter values are
recommended:
BOD5 - 0.01 kg/kkg (0.01 lb/1000 Ib) anhydrous soap
COD - 0.05 kg/kkg (0.05 ;bs/1000 Ib) anhydrous soap
Suspended Solids - 0.01 kg/kkg (0.01 lb/1000 Ib) anhydrous soap
Oil and Grease - 0.01 kg/kkg (0.01 lb/1000 Ib) anhydrous soap
pH 6.0-9.0
There may be an occasional need on the part of some .manufacturers to
exceed these limits due to a highly varied product mix requiring
washouts more frequently than allowed above. An upset allowance <>f one
to two times the monthly average should be applied.
Best Practicable Control Technology Currently Available
secondary biological treatment is adequate to meet the levels proposed.
R at ion a le _a nd_ A s s ump_t i on s
This processing step is essentially clean, requiring only rare washouts
to prevent cross contamination of widely varied performance products.
Many of these same processors blend dry detergents requiring comparable
frequency of washouts. A biological secondary treatment is expected to
be adequate to handle the effluents.
20J - OLEUM SULFONATION/SULFATION
124
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General
This chemical process has been optimized in that it is close to a "push
button" operation. It is practically troublefree and requires washdowns
only when there is to be maintenance of the operating equipment. Th
leaking pump glands are a problem typical of this kind of equipment, bu
modest in nature. Normally an operator can quickly observe
significant leak and repair it promptly.
Raw_Waste_Loading
An average expected raw waste loading is:
BOD5 - 0.2 kg/kkg (0.2 lb/1000 Ib) anhydrous product
COD - 0.6 kg/kkg (0.6 lb/1000 Ib) anhydrous product
Suspended Solids - 0.3 kg/kkg (0.3 lb/1000 Ib) anhydrous
product
Oil and Grease - 0.3 kg/kkg (0.3 lb/1000 Ib) anhydrous product
Surfactant - 0.7 kg/kkg (0.7 lb/1000 Ib) anhydrous product
i£S£-Practicab].e_control_Technglggy Currently Avail able _Gn id gjjn^g
The following thirty day average recommendations for effluent loadings
are made with the understanding that there may be some firms on some
occasions requiring additional loadings for washouts of equipment.
Further, during any 24 hour period the limits could be allowed to
approach 3 times the average as long as the thirty day average meets the
guidelines.
BOD5 - 0.02 kg/kkg (0.02 lb/1000 Ib) anhydrous product
COD - 0.09 kg/kkg (0.09 lb/1000 Ib) anhydrous product
Suspended Solids - 0.03 kg/kkg (0.03 lb/1000 Ib) anhydrous
product
Dil and Grease - 0.03 kg/kkg (0.03 lb/1000 Ib) anhydrous product
Surfactant - 0.07 kg/kkg (0.07 lb/1000 Ib) anhydrous product
?H 6.0-9.0
Some small scale batch operated plants may have great difficulty in
reaching these levels. Consideration should be given by the permit
writing authority for modest relaxation of these levels where
circumstances clearly warrant them.
3est_Practicable Control Technology Currently Availahv>
125
-------
As indicated in the general discussion this process can be operated
continuously in essentially a trouble-free manner. There is little room
for improvement.
Other than the gland leakage and very occasional washouts this process
has no effluent. Gland leakage around pump shafts is a universal
problem wherever liquids are handled, particularly corrosive liquids.
Because of the corrosive nature of the oleum, thorough washouts are
mandatory prior to maintenance work being carried out on the equipment.
Integrated plants will have little difficulty meeting the levels of the
guidelines. The washwater can be recycled and the leaks and spills run
to the neutralization unit.
Biological secondary treatment will handle the residual wastes when they
occur.
2^2_-_AIP-Sg3_SyLFATION/SULFONATION
General
This process is in as widespread use as the oleum sulfonation (201),
particularly for the sulfation of alcohols and ethoxylates. Although
continuous and automatic, the Air - SO3 process is much more inclined to
cause product degradation than the oleum unit.
Whenever the process is started up some material must be discarded due
to low sulfonation making the material below specification. Promptly
upon shutdown a thorough washdcwn is required to keep char formation to
a minimum. There are mist knockdown scrubbers which will also
contribute to waste water loadings.
Raw Waste Loading
Average expected raw waste loadings are:
BOD5 - 3 kg/kkg (3 lb/1000 Ib) anhydrous product
COD - 9 kg/kkg (9 lb/1000 Ib) anhydrous product
Suspended Solids - 0.3 kg/kkg (0.3 lb/1000 Ib)
anhydrous product
Surfactant - 3 kg/kkg (3 115/1000 Ib) anhydrous
product
Oil and Grease - 0.5 kg/kkg (0.5 lb/1000 Ib)
anhydrous product
Best Practicable control Technology Currently Available Guidelines
Thirty day average recommendations are made on a similar basis as those
for Subcategory 201 - Oleum Sulfonation. Because of product changes or
126
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mechanical failures some plants may, at times, have to exceed
established effluent limits. Such cases have not been provided for in
suggested guidelines. Therefore, regulatory agencies may wish -co extend
special consideration in such cases and write appropriate limitations
into any permits they issue.
BOD5 - 0.30 kg/kkg (0.30 lb/1000 It) anhydrous product
COD - 1.35 kg/kkg (1.35 lb/1000 Ib) anhydrous product
Suspended Solids - 0.03 kg/kkg (0.03 lb/10,00 Ib)
anhydrous product
Surfactant - 0.30 kg/kkg (0.30 It/1000 Ib) anhydrous
product
Oil and Grease - 0.05 kg/kkg (0.05 lb/1000 Ib) anhydrous
product
pH 6.0 - 9.0
An upset allowance of one to two times the monthly average should apply.
Best Practicable_Contrgl Technology Currently^Available
This process too has received much research and development attention
leaving little to be expected in the short term in the form of process
improvement.
In-plant practices can significantly aid in reducing raw waste loads by
handling much of the cleanup dry, or blending off the material into
industrial cleaners, provided the firm is sufficiently integrated.
Rationale and Assumptions
In small plants particularly, there must be accommodation made for the
disposal of these rather minimal wastes, in that the off specification
product could seriously impact the product quality if incorporated in
that stream.
The raw waste loading has been structured higher than that for oleum
sulfonation to acknowledge the product degradation which takes place
when sulfonated material remains in the reaction area, requiring
thorough washouts.
203 - SO3 SOLVENT AND VACUUM SULFONATICN
General
Other than an occasional washout, this process is essentially free of
waste water generation.
127
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Raw^Waste Loading
The following raw waste loading is expected:
BOD5 - 3 kg/kkg (3 lb/1000 Ib) anhydrous product
COD - 9 kg/kkg (9 lb/1000 Ib) anhydrous product
Suspended Solids - 0.3 kg/kkg (0.30 lb/1000 Ib)
anhydrous product
Surfactant - 3 kg/kkg (3 lb/1000 Ib) anhydrous
product
Oil and Grease - 0.5 kg/kkg (0.5 lb/1000 Ib) anhydrous
product
Rest_Practicable_Control_Technology Currently Available (guidelines
On a thirty day average basis, the following parameter levels are
recommended:
BOD5 - 0.30 kg/kkg (0.30 lb/1000 Ib) anhydrous product
COD - 1.35 kg/kkg (1.35 lb/1000 Ib) anhydrous product
Suspended Solids - 0.03 kg/kkg (0.03 lb/1000 Ib)
anhydrous product
Surfactant - 0.30 kg/kkg (0.30 lbs/1000 Ibs) anhydrous
product
Oil and Grease - 0.05 kg/kkg (0.05 lb/1000 Ib) anhydrous
product
pH 6.0-9.0
No additional allowance need be made for startup, shutdown
or upset conditions.
SSS^j^g^tig-able^Contrgl Technology Currently Available
Secondary biological treatment will adequately handle the
wastes from this process.
Rationale
As in other categories, there will be some occasions when
washouts will be required.
Z-g.ULgAMIC ACID SULFATIQN
128
-------
General
Washouts are the only waste water effluents from this pro-
cess.
Raw Waste Loading
The following raw waste loading is expected:
BOD5 - 3 kg/kkg (3 lb/1000 Ib) anhydrous product
COD - 9 kg/kkg (9 lb/1000 Ib) anhydrous product
Suspended Solids - 0.3 kg/kkg (0.3 lb/1000 Ib)
anhydrous product
Surfactant - 3 kg/kkg (3 lb/1000 Ib) anhydrous
product
Oil and Grease - 0.5 kg/kkg (0.5 lb/1000 Ib) anhy-
drous product
Best Practicable Control_Technoloqy Currently Available Guidelines
On a thirty day average basis, the following parameter levels are
recommended:
BOD5 - 0.3 kg/kkg (0.3 lb/1000 Ib) anhydrous pro-
duct
COD - 1.35 kg/kkg (1.35 lb/1000 Ib) anhydrous product
Suspended Solids - 0.03 kg/kkg (0.03 lb/1000 Ib)
anhydrous product
Surfactant - 0.3 kg/kkg (0.3 lb/1000 Ib) anhydrous
product
Oil and Grease - 0.05 kg/kkg (0.05 lb/1000 Ib) anhy-
drous product
pH 6.0-9.0
No startup, shutdown or upset allowance is recommended.
Best^ Practicable .Control Technology Currently Available
In order to comply with these guidelines the operator would be obliged
to recycle the wash water rather than sewer it.
Rationale
129
-------
This reaction is normally carried out in batches. Reasonable
housekeeping would permit the recycle via a holding tank for most of the
washwater. As in other processes, this one can either accumulate
unusable amounts of dilute washwater or occasionally have off-
specification material to be disposed of. Unlike a large integrated
plant, the firm using this process is unlikely to have any alternative
other than disposal.
2Q5_- CHLOROSULFONIC ACID SULFATION
General
This specialized process is another route to a high quality surfactant
produced uniquely under mild reaction conditions. The by-product HCl is
a significant distinction from other sulfonation processes. It is
usually scrubbed out in a caustic solution with the formation of salt or
dissolved in water for sale as muriatic acid.
Raw_Waste Loading
The followina values can be expected on a thirty day basis:
BOD5 - 3 kg/kkg (3 lb/1000 Ib) anhydrous product
COD - 9 kg/kkg (9 lb/1000 Ib) anhydrous product
Suspended Solids - 0.3 kg/kkg (0.3 lb/1000 Ib)
anhydrous product
Surfactant - 3 kg/kkg (3 lb/1000 Ib) anhydrous pro-
duct
Oil and Grease - 0.5 kg/kkg (0.5 lb/1000 Ib) anhydrous
product
Best Practicable Control__Technoloqy Currently Available Guidelines
As a thirty day average the following parameter levels are
recommended:
BOD5 - 0.3 kg/kkg (0.3 lb/1000 Ib) anhydrous product
COD - 1.35 kg/kkg (1.35 lb/1000 Ib) anhydrous product
Suspended Solids - 0.03 kg/kkg (0.03 lb/1000 Ib)
anhydrous product
Surfactant - 0.30 kg/kkg (0.30 lb/1000 Ib) anhydrous
product
Oil and Grease - 0.05 kg/kkg (0.05 lb/1000 Ib) anhy-
drous product
130
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pH 6.0-9.0
No upsets, startup or shutdown allowances are recommended.
This important, moderately used process is optimized to the extent
reasonably expected.
Rationale
The effluent washouts are minimal and the required loadings reasonable
in relationship to the other processes. Recycling washouts can
materially aid in meeting these guidelines. Biological secondary
treatment is adequate to handle the expected raw waste load.
206 - NEyTRALIZATIQN_QF_SULFyRIC_ACID_ESTERS_AND_SyLFONIC_ACIDS
General
Neutralization is the essential step which converts the sulfonic acids
or sulfuric acid esters into neutral surfactants. It is a potential
source of some oil and grease generation due to the possiDle hydrolysis
of the sulfates. Occasional leaks and spills around the pump, valves,
etc., are the only expected source of waste water contamination.
Raw Waste Loading
The following loadings can be expected:
BOD5 - 0.10 kg/kkg (0.10 lb/1000 Ib) anhydrous product
COD - 0.3 kg/kkg (0.3 lb/1000 Ib) anhydrous product
Suspended Solids - 0.3 kg/kkg (0.3 lb/1000 Ib) anhy-
drous product
Surfactant - 0.2 kg/kkg (0.2 lb/1000 Ib) anhydrous
product
Oil and Grease - 0.1 kg/kkg (0.1 lb/1000 Ib) anhydrous
product
Best Practicable control Technology Currently Available Guidelines
On a thirty day average basis the following parameter values are
recommended :
BOD5 - 0.01 kg/kkg (0.01 lb/1000 Ib) anhydrous product
COD - 0.05 kg/kkg (0.05 lb/1000 Ib) anhydrous product
Suspended Solids - 0.03 kg/kkg (0.03 lb/1000 Ib) anhy-
131
-------
drous product
Surfactant - 0.02 kg/kkg (0.02 lb/1000 Ib) anhydrous
product
Oil and Grease - 0.01 kg/kkg (0.01 lb/1000 Ib) anhydrous
product
pH 6.0-9.0
No startup, shutdown or upset allowances are recommended.
Best^Practicable Control Technology Currently,,Available
This process step is quite simple and usually continuous when in tandem
with a continuous sulfonator. The biotreater in secondary treatment
processing can accommodate the load. Recycle is probably the best way
to eliminate waste loads.
Rationale
In a large volume operation of this type there will be occasional
inadverten-t- leaks of valve and pump packing, spills due to maintenance
disruption of piping, and occasional cleanup to repair the equipment,
all necessitating the generation of dilute waste water streams. These
streams are usually too dilute for recycle back into the process, but by
use of small amounts of water, recyle is practical. By storage and
recycle some of this washout water could diminish the problem and lead
to product recovery later in the finishing process.
20J_-_SPRAY_DRIED_DETERGENTS_
General
This unit operation is one of the most critical - and the largest - as
well as the most important of the detergent industry. Here, the final
detergent particles are formed which must have the appropriate physical
characteristics for solubility, packaging and storage.
Tower cleanliness is essential so that degradation products or material
significantly different made in an earlier run do not contaminate the
currently processed product. In such a case, the spray tower is put
through a multi-stage, thorough cleaning process.
After the large dry "chunks" of adhering detergent are knocked down by
hand, the tower walls are abraded. Finally, water is played over the
surface to finish the cleaning process. The frequency of tower
"turnaround" varies considerably in practice. Some towers operate for
many weeks before shutdown and washing. Others may have a tower
changeover sixteen times in a given month. In many cases there are
product changeovers made on-the-fly requiring neither stoppage of spray
tower operation nor cleanout.
132
-------
Among many of the towers which have extended runs on one product, there
is minimal discharge as waste water effluent. All of the dry product is
recycled or sent to solid waste disposal. The washwater and scrubber
water is all sent back into the process and recycled to extinction.
There are numerous possible sources of water containing contaminants
originating in this process. They encompass crutcher cleanouts,
packaging equipment cleanouts, storage area washouts, vent scrubbers,
etc.
Characteristics of the exit air coming out of the spray tower are
largely determined by the composition of the detergent formulation being
dried. The increasing use of alcohol sulfates and ethoxylated alcohols
as active ingredients has increased plume generation in this air stream
which is not effectively eliminated by mechanical and electrostatic
methods, thus resulting in a significant volume of scrubber water being
employed.
The total volume of scrubber water and washouts becomes too great to be
recycled to extinction in some spray tower operations when they have to
meet source air standards. Consequently, some waste water is expected
to be sent to the sewer under these conditions.
A similar problem is faced by those who operate spray towers on a fast
turnaround basis. They end up with much more washout waste water than
they can handle via recycle.
In both cases cited above, the other immediately apparent alternative is
to reuse all of the water, forcing the solids concentration of the tower
slurry from around 70 percent to some lower value. This is not a
suitable alternative, particularly from an environmental viewpoint,
since excessive energy consumption would be required to drive off the
additional water.
Raw Waste Loading
Under normal spray tower operation, a thirty day average raw waste
loading can be expected to reach:
BOD5 -0.1 kg/kkg (0.1 lb/1000 Ib) anhydrous product
COD - 0.3 kg/kkg (0.3 lb/1000 Ib) anhydrous product
Suspended Solids - 0.1 kg/kkg (0.1 lb/1000 Ib) anhy-
drous product
Surfactant - 0.2 kg/kkg (0.2 lb/1000 Ib) anhydrous product
In towers facing particularly stringent air quality problems, the
following waste water loadings can be expected:
BOD5 - 0.8 kg/kkg (0.8 lb/1000 Ib) anhydrous product
COD - 2.5 kg/kkg (2.5 lb/1000 Ib) anhydrous product
133
-------
Suspended Solids - 1.0 kg/kkg (1.0 lb/1000 Ib) anhy-
drous product
Surfactanr -1.5 kg/kkg (1.5 lb/1000 Ib) anhydrous
product
Oil and Grease - 0.3 kg/kkg (0.3 lb/1000 Ib) anhydrous
oroduct
In spray towers having fast turnarounds (more than 6 per month), for
each added turnaround, the following additional waste water loadings can
be expected:
BOD5 - 2.0 kg/kkg (2.0 lb/1000 Ib) anhydrous product
COD - 6.0 kg/kkg (6.0 lb/1000 Ib) anhydrous product
Suspended Solids - 2.0 kg/kkg (2.0 lb/1000 Ib) anhydrous
product
Surfactant - H.O kg/kkg (4.0 lb/1000 Ib) anhydrous
product
Oil and Grease - 0.3 kg/kkg (0.3 lb/1000 Ib) anhydrous
product
Best_Practicable Control Technology Currently Available Guidelines
For normal spray tower operation the following thirty day average
parameter values are recommended:
BOD5 - 0.01 kg/kkg (0.01 lb/1000 Ib) anhydrous product
COD - 0.05 kg/kkg (0.05 lb/1000 Ib) anhydrous product
Suspended Solids - 0.01 kg/kkg (0.01 lb/1000 Ib) anhy-
drous product
Surfactant - 0.02 kg/kkg (0.02 lb/1000 Ib) anhydrous
product
pH - 6.0 - 9.0
No special startup, shutdown or upset allowances are recommended.
For spray towers operating under stringent air quality problems, the
thirty day average parameter loading guideline recommendcitions are:
BOD5 - 0.08 kg /kkg (0.08 lb/1000 Ib) anhydrous product
COD - 0.37 kg /kkg (0.37 lb/1000 Ib) anhydrous product
134
-------
Suspended Solids - 0.10 kg /kkg (0.10 lb/1000 lb) an-
hydrous product
Surfactant - 0.15 kg/kkg (0.15 lb/1000 lb) anhydrous
product
Oil and Grease - 0.03 kg/kkg (0.03 lb/1000 lb) anhy-
drous product
pH - 6.0 - 9.0
For spray tower operation with fast turnaround, the following additional
allowance should be made for each turnaround above 6 per month:
BOD5 - 0.02 kg/kkg (0.02 lb/1000 lb) anhydrous product
COD - 0.09 kg/kkg (0.09 lb/1000 lb) anhydrous product
Suspended Solids - 0.02 kg/kkg (0.02 lb/1000 lb) an-
hydrous product
Surfactant - 0.04 kg/kkg (0.04 lb/1000 lb) anhydrous
product
Oil and Grease - no additional allowance
pH - 6.0 - 9.0
This is in essence an upset allowance for shutdown and startup.
No other special upset allowances are recommended for spray tower
operations in general.
Best_Practicable Control_Technology Currently^Ayailable
It is expected that the levels of effluent constituents can be met
readily if the equivalent cf cyclone scrubbers are used before
electrostatic precipitators in the air stream exiting from the spray
tower. Since the function of the water scrubbing is to chill the air as
well as remove particulate matter, a significant step toward reduced
effluent loading can be taken by substituting cooled recycle water for
that used on a once through basis.
With the water recycled, a sufficient concentration can be built up in
the water flow to make return to the detergent making process possible.
Foaming is avoided by maintaining the surfactant concentration at a
sufficiently high level in the recycled scrubber water.
Ultimately, the secondary biotreater will have no difficulty processing
the waste load from the spray tower area.
Rationale
135
-------
The demands for clean air and clean water come into conflict in sprav
tower operation. in order to meet the increasingly tighter air
pollution regulations while producing products which are more
environmentally compatible, tower operation problems develop. These
newer formulations contain increasing amounts of nonionic surfactanrs
which are prone to produce an aerosol plume that persists in the exit
tower gas.
A system of dry cyclone dust collectors followed by an electrostatic
precipitator is suitable for removing the particulate matter present,
but it does not influence the plume since it is a vapor.
By inserting a wet scrubber in between the cyclone dust collector and
the electrostatic precipitator the particulate matter is further reduced
and the organic aerosol vapors are condensed so that they can then be
removed by the electrostatic precipitator.
Introduction of this scrubber water flow now converts a potential air
contamination into a waste water problem. Since the materials removed
in the scrubber are biodegradable and essentially the same product as
that which is out into our sanitary sewers throughout the country, this
is a satisfactory method of minimizing the environmental impact.
Additional study is needed in this area, particularly concerning the
economics of installing sufficient tankage to enable tne fast turnaround
towers to approach total recycle.
208_L_LI2UID_DETERGENT_MANUFACTURE
General
There are numerous liquid detergent products made and it is likely that
they are going to become more abundant as more emphasis is placed upon
nonphosphate products. Many products, including heavy-duty detergents,
are more amenable to convenient use and manufacture in the liquid form
than as a dry powder.
The term "liquid detergents" embraces a large variety of formulations
which fulfill an equally large spectrum of uses. The ingredients used
to formulate the products have a wide response to such tests as BOD^.
Consequently, the statement of any single raw waste loading could cause
a significant problem to a given manufacturer.
In the process of preparing the liquid detergent, there are two main
sources of waste water effluent, mixing equipment and distribution
system washouts and filling equipment cleanup. Most operators recycle
as much diluted product as possible, but, as in the case of spray tower
operation, the total water volume canr.ot be economically recycled to
extinction.
136
-------
On a -thirty day average basis, the following raw waste loadings will be
"xoerienced:
ROD5 - 2 kg/kkg (2 lb/1000 Ib) anhydrous product
COD - a kg/kkg (4 lb/1000 Ib) anhydrous product
Surfactant - 1.3 kg/kkg (1.3 lb/1000 Ib) anhydrous product
However, when observing smaller firms, the raw waste loadings may get
T.O :
3OD5 - 5 kg/kkg (5 lb/1000 Ib) anhydrous product
COD - 7 kg/kkg (7 lb/1000 Ib) ar.hydrous product
Surfactant - 3.3 kg/kkg (3.3 lb/1000 Ib) anhydrous
product
This latter case is associated with the high use of common transfer
lines for moving the product to filling lines, losses resulting from
breaking hose connections and relatively short filling runs.
Best Practicable Control Technology Currently Available Guidelines
On a thirty day average basis, the following parameter levels are
recommended:
BOD5 - 0.2 kg/kkg (0.2 lb/1000 Ib) anhydrous product
COD - 0.6 kg/kkg (0.6 lb/1000 Ib) anhydrous product
Surfactant - 0.13 kg/kkg (0.13 lb/1000 Ib) anhy-
drous product
pH - 6.0 - 9.0
There should be some accommodations made for the smaller operator where
his loadings are marginally greater than those shown. Another exception
which should be noted is that the COD/EODJ5 ratio may rise to 5:1 or more
due to the use of some relatively bio-hard indusrrial cleaner
inqredients such as orthodichlorobenzene, hydrochloric acid, or chromic
acid. Such compounds can upset the biota in BOD5^ tests, as well as
cfiving a refractory residue. No allowance need be made for the
suspended solids or oil and grease since the products marketed are
normally clear, filtered fluids, devoid of suspended particles.
Best_Practicable_Control Technology Currently Available
Secondary biological treatment will adequately handle the waste water
effluents from this process.
137
-------
Rationale
With an industry very much aware of market demands, there will be a
continually changing array of formulations to meet new consumer
preferences and environmental performance demands. There are generally
two different markets for liquid detergents; household and industrial.
In this latter market, many moderately sized operators supply a wide
variety of special purpose detergents to meet very specialized needs.
Often fairly "exotic" materials are used.
Relatively small operators dc not have the flexibility of operation of
the large manufacturers. This, coupled with numerous small batches of
product, creates special waste water problems, since there is no place
to hold or recycle numerous, varied spills, leaks and washouts. The
cut-off point in allowances becomes critical, then, since it could have
severe economic consequences for some manufacturers. There are other
special problems relating to analytical results of effluent evaluations.
Due to the wide variety of products used in liquid formulations, fully
acclimated cultures may not be available for gaining results which
reflect the actual technical conditions.
209_-_DRY_DETERGENT_BLENDING
General
Many different dry detergent blends are made for a multiplicity of
industrial uses. The product is usually marketed in drums.
The customary practice is for many successive batches to be made in a
given mixer before a wet washdown is required.
Raw_Waste_Load:Lng
An average thirty day waste water leading would be:
BOD5 - 0.1 kg/kkg (0.1 lb/1000 Ib) anhydrous pro-
duct
Suspended Solids - 0.1 kg/kkg (0.1 lb/1000 Ibs) anhydrous product
COD - 0.5 kg/kkg (0.5 lb/1000 Ib) anhydrous product
Surfactant - 0.1 kg/kkg (0.1 lb/1000 Ib) anhydrous product
Bes_t_Practicable_Cgntrol Technology Currently Available Guidelines
Based upon a thirty day average, the recommendations of parameter
loadings are:
BOD5_ - 0.01 kg/kkg (0.01 lb/1000 Ib) anhydrous pro-
duct
138
-------
COD - 0.08 kg/kkg (0.08 lb/1000 It) anhydrous pro-
duct
Suspended Solids - 0.01 kg/kkg (0.01 lb/1000 Ib)
anhydrous product
Surfactant - 0.01 kg/kkg (0.01 lb/1000 Ib) anhy-
drous product
pH - 6.0 - 9.0
No additional allowance need be made for startup, shutdown, or upsets.
Best_Practicab_le CgntrQl_Technglogy_ Currently Available
Biological secondary treatment is adequate for the effluent involved.
Rationale
A wide variety of materials are formulated dry. Although little water
is used, that which is required for the infrequent washings is critical.
It will be very dilute and diverse in content, unsuitaole for recycling.
2_10_:_DRyM_pRIEp_pETERGENTS
Genera].
This well established process produces no effluent, but some provision
must be made for those periods of mandatory washdown due to equipment
failure or critical formulation change.
Raw Waste Loading
The average raw waste load which could be expected is:
BOD5 - 0.1 kg/kkg (0.1 lb/1000 Ib) anhydrous pro-
duct
COD - 0.3 kg/kkg (0.3 lb/1000 Ib) anhydrous pro-
duct
Suspended Solids - 0.1 kg/kkg (0.1 lb/1000 Ib) anhy-
drous product
Surfactant - 0.1 kg/kkg (0.1 lb/1000 Ib) anhy-
drous product
Oil and Grease - 0.1 kg/kkg (0.1 lb/1000 Ib) an-
hydrous product
Best Practicable Control Technology Currently Available Guidelines
139
-------
On a thirty day average basis, the following parameter levels are
recommended:
BOD5 - 0.01 kg/kkg (0.01 lb/1000 It) anhydrous
product
COD - 0.05 kg/kkg (0.05 lb/1000 Ib) anhydrous
product
Suspended Solids - 0.01 kg/kkg (0.01 lb/1000 Ib)
anhydrous product
Surfactant - 0.01 kg/kkg (0.01 lb/1000 Ib) anhy-
drous product
Oil and Grease - 0.01 kg/kkg (0.01 lb/1000'lb) an-
hydrous product
pH - 6.0 - 9.0
No startup, shutdown or upset allowances are required. Due to the low
values recommended, a total of three times the average should be allowed
over any 24 hour period as long as during any thirty day period the
guidelines are maintained.
Best Practicable Control Technology Currently Available
Secondary biological treatment can adequately handle the constituents.
Rationale
Even though the process is essentially dry, the slurry pans and other
equipment will require an infrequent but necessary and thorough washout.
211 - DETERGENT BARS,AND CAKES
General
In the manufacture of detergent bars there is need for meticulous
cleaning of equipment to insure that any product which may have been
degraded due to adhering to hot process equipment is removed and
disposed of.
The approximately 160 million pounds cf synthetic toilet bar soap used
in the U.S. is significant, yet modest when compared to the 600 million
pounds of "natural" soap used in toilet bars.
Raw Waste Loading
The following raw waste load can be expected:
BOD5 - 7 kg/kkg (7 lb/1000 lb) anhydrous product
140
-------
COD - 22 kg/kkg (22 lb/1000 Ib) anhydrous product
Suspended Solids - 2 kg/kkg (2 lb/1000 Ib) anhy-
drous product
Surfactant - 5 kg/kkg (5 lb/1000 Ib) anhydrous
product
Oil and Grease - 0.2 kg/kkg (0.2 lb/1000 Ib) anhy-
drous product
Best Practicable Control Technology Currently Ayailable Guidelines
On the basis of a thirty day average, the following parameter levels are
recommended:
BOD5 - 0.7 kg/kkg (0.7 lb/1000 Ib) anhydrous pro-
duct
COD - 3.3 kg/kkg (3.3 lb/1000 Ib) anhydrous product
Suspended Solids - 0.2 kg/kkg (0.2 lb/1000 Ib) an-
hydrous product
Oil and Grease - 0.02 kg/kkg (0.02 lb/1000 Ib) an-
hydrous product
pH - 6 - 9
No additional allowance is recommended for startup, shutdown or upsets.
During any thirty day period an allowance of three times the average
should be allowed over a 24 hour duration, provided that throughout the
entire thirty day period the thirty day average is not exceeded.
141
-------
SECTION X
BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE
Introduction
Best available technology economically achievable is,expected to involve
both improvement in the manufacturing process as well as adoption of the
best available treatment technology that is within reason economically.
Not all of the processes identified in best practicable control
technology currently available are expected to discharge less effluent
by 1983. Several of these processes will have reached an optimum raw
effluent reduction in compliance with the best practicable control
technology currently available, attaining pollution levels so low that
it is not feasible to reflect minor improvements in end-of-pipe
treatment through reduced guideline values. Only those which are
expected to attain a lower effluent level are discussed in detail in
this section.
TABLE 7-1
Best Available Technology Economically Achievable Guidelines Reflecting
No Change From Best Practicable control Technology Currently Available
Note: All values are reported as thirty day averages in kg/kkg (lb/1000
Ib) of anhydrous product made in that subcategory. The pH for all sub-
categories is the range of 6.0 - 9.0.
BOD5 COD Suspended Oil &
Solids Surfactant Grease
Fatty Acid by Fat
Splitting-Hydrogenation
Allowance Only 0.25 0.20 0.20 0.00 0.15
Soap From Fatty Acid
Neutralization 0.01 0.05 0.02 0.00 0.01
Soap Flakes and
Powders 0.01 0.05 0.01 0.00 0.01
Liquid Soaps 0.01 0.05 0.01 0.00 0.01
Oleum Sulfonation/
Sulfation 0.02 0.09 0.03 0.03 0.07
S03 Solvent and
Vacuum Sulfonation 0.10 0.45 0.01 0.10 0.02
Neutralization of
Acids 0.01 0.05 0.03 0.02 0.01
143
-------
Detergent Dry
Blending 0.01 0.08 0.01 0.01 0.005
Drum Dried
Detergents 0.01 0.05 0.01 0.01 0.01
TABLE 7-2
Best Available Technology Economically Achievable Guidelines Reflecting
Changes From Best Practicable Control Technology Currently Available
Note: All values are reported as thirty day averages in Kg/kkg (lb/1000
Ib) of anhydrous product made in that subcategory. The pH for all sub-
categories is the range of 6.0 - 9.0.
Suspended Oil £
BOD5 COD Solids Surfactant Grease
Batch Kettle Soap O.aO 1.05 0.40 0.0 0.05
Fatty Acid by
Fat Splitting 0.25 0.90 0.20 0.0 0.15
Glycerine concentration 0.40 1.20 0.10 0.0 0.04
Glycerine Distillation 0.30 0.90 0.04 0.0 0.02
Bar Soaps 0.20 0.60 0.34 0.0 0.01
Air-SOS Sulfation/
Sulfonation 0.19 0.60 0.02 0.18 0.04
Sulfamic Acid
Sulfation 0.10 0.45 0.01 0.10 0.02
Chlorosulfonic
Acid Sulfation 0.15 0.75 0.02 0.15 0.03
Spray Dried
Detergents
Normal 0.01 0.08 0.01 0.02 0.00
Air Quality
Restricted 0.08 0.35 0.10 0.15 0.03
Fast
Turnaround 0.02 0.09 0.02 0.03 0.00
Liquid Detergents 0.05 0.23 0.005 0.05 0.00
Detergent Bars
and Cakes 0.30 1.35 0.10 0.20 0.02
144
-------
l^l_-_MODIFIED_SOAP_MANUFACTyRE_EY_BATCH_^ITTLE
Best_Available_TechnolggY Economical ly Achievable _ a nd_ Rationale
A significant reduction of waste water contamination volume can be made
in the fat pretreatment step of kettle boiling soap manufacture by
replacing the barometric condenser used in vacuum bleaching by a surface
condenser. Such replacement would allow removal of volatile low
molecular weight undesirables frcm the effluent. These can be destroyed
by burning or perhaps recovered for sale by refining. This change is
shown in Figure 26.
Raw_Waste_Loading
The expected raw waste load is:
BOD5 - 4 kg/kkg (4 lb/1000 Ib) anhydrous soap
COD - 7 kg/kkg (7 lb/1000 Ib) anhydrous soap
Suspended Solids - U kg/kkg (U lb/1000 Ib) anhy-
drous soap
Oil and Grease - 0.5 kg/kkg (0.5 lb/1000 Ib) an-
hydrous soap
Bes_tAvaalabe
Guidelines
Please refer to guidelines in Table 7-2 at beginning of this Section
S§s^-^Yg:ilable_TechnologY_Economically Achievable and_Rationale
Referring to the schematic flow diagram 102, there are two ways of
diminishing further the effluent streams from this unit. The first of
*:hese is in-process recycle of the process condensate to the maximum
extent possible. Secondly, the barometric condenser of the fatty acid
distillation process can be replaced with a surface condenser thereby
reducing by approximately 80 percent the amount of light ends going into
the waste water stream during acid separation and purification. These
light ends can be recovered for sale. The water stream can be then
recycled back into the fat splitting process. The overall process
(including hydrogenation) is shown in Figures 27 and 28.
Raw_Waste _, Loadings
The following raw waste loadings can be expected.
BOD5 - 2.5 kg/kkg (2.5 lb/1000 Ib) anhydrous fatty acid
COD - 6.0 kg/kkg (6.0 lb/1000 Ib) anhydrous fatty acid
145
-------
-p-
cr>
SECTION X
LEVEL II TECHNOLOGY
101 - SOAP MANUFACTURE BY BATCH KETTLE : MODIFIED
Wll RECEIVING
STORAGE TRANSFER
1012 FAT REFINING
AND BLEACHING
Wt3 SOAP BOILING
NEAT SOAP TO
"PROCESSING
AND SALE
GLYCERINE TO
RECOVERY
LOW GRADE SOAP
LOW GRADE
FATTY ACID
FIGURE 26
-------
and
LEVEL III TECHNOLOGY
102 Modified: FATTY ACID MANUFACTURE BY FAT SPLITTING
7021 RECEIVING
STORAGE TRANSFER
»TS AND
LS
FATTY ACIDS
TO SALES.
'NEUTRALIZATION
OR HYDROGENATION
FIGURE 27
-------
and XI
LEVEL II TECHNOLOGY
and
LEVEL III TECHNOLOGY
SCHEMATIC - 102-H: FATTY ACIDS MANUFACTURE : HYDROGENATION STEP, IF CARRIED OUT.
RECYCLE -<
TO:
DISTILLATION
OF FATTY ACIDS
FATTY ACIDS
FEED TO
HYDROGENATION
FROM:
102-M
PUMP
CATALYST
BED
OR
SUSPENDED
CATALYST
WITH
TRAYS
DEMISTER
FROM
STORAGE
COMPRESSOR
HYDROGENATED
FATTY ACIDS TO:
SALES OR
NEUTRALIZATION
HYDROGENATED
FATTY ACIDS
HYDROGEN:
FROM SUPPLIER
FILTER OR
CATALYST
PHASED
REMOVAL
BLEED
IMPURITIES
TO SUPPLIER
OR VENT:
TO STACK
SPENT
CATALYST
AND
POLYMERS
-------
Suspended solids - 2.0 kg/kkg (2.0 It/1000 Ib) anhydrous
fatty acid
Oil and Grease - 1.5 kg/kkg (1.5 lb/1000 Ib) anhydrous
fatty acid
Best Available Techno logy __ Economic ally Achievable Guidelines
Please refer to guidelines in Table 7-2 at beginning of this Section.
IM-Z-GLYCERI NE_RECOV ERY_ AND_ CONCENTRATION
Best Available Technology^Economically^ Achievable^and Rationale
Replacement of the barometric legs in both the glycerine concentration
and distillation processes would reduce glycerine losses and waste water
loadings substantially. These changes are shown in Figures 29 and 30.
Raw_Waste_Load
The following average raw waste load is expected:
Glycerine Concentration
BOD5 - 4.0 kg/kkg (4.0 lb/1000 Ib) anhydrous glycerine
COD - 8.0 kg/kkg (8.0 lb/1000 Ib) anhydrous glycerine
Suspended Solids - 1.0 kg/kkg ( 1.0 lb/1000 Ib) anhydrous
glycerine
Oil and Grease - 0.4 kg/kkg (0.4 lb/1000 Ib) anhydrous
glycerine
Glycerine^Distillation
BOD5 - 3.0 kg/kkg (3.0 lb/1000 Ib) anhydrous glycerine
COD - 6.0 kg/kkg (6.0 lb/1000 Ib) anhydrous glycerine
Suspended Solids - 0.4 kg/kkg (0.4 lb/1000 Ib) anhydrous
glycerine
Oil and Grease - 0.2 kg/kkg (0.2 lb/1000 Ib) anhydrous
glycerine
Best_Avaj.lable_Technglogy Economically, Achievable Guidelines
Please refer to guidelines in Table 7-2 at beginning of this Section.
PROCESS 106 - BAR SOAPS
149
-------
104 GLYCERINE RECOVERY
1041 RECEIVING
STORAGE-TRANSFER
043 GLYCERINE EVAPORATION TO 80% CONCENTRATION
SOAP MAKING
SOLUTION MAKE-UP
80% GLYCERINE TO CONCENTRATOR
HEAVY ENDS TO FOOTS STILL
-------
104-B: CONCENTRATION OF 80% GLYCERINE TO 99.5%
1044 GLYCERINE STILL
80%GLYCER1NE
from 104 A
HEAVY ENDS
from 104 A
FOOTS TO FLARE
OR WASH TO SEWER
REFINED GLYCERINE
99 5% GLYCERINE
TO SALES
Dry Caustic Soda
WASH I LIQUID
BLEED: TO FLARE
~"
SODA
Dry Salt
Jf
SALT
^, Water
^ HEAVY ENDS TO
FOOTS STJLL
RECYCLE SALT TO.
SOAP MAKING
RECYCLE CAUSTIC
TO SOAP MAKING
FIGURE 30
-------
Best Available Technology Economically Achievable_and_RataQnale
By 1983 there is an expectancy that the current relatively high BOD5_
waste load from air scrubbing will be improved to more closely match
those operations which now are experiencing very low discnarge rates.
Raw Waste Load
The following average raw waste load is expected:
BOD5 - 2.0 kg /kkg (2.0 lb/1000 Ib) anhydrous soap
COD - 4.0 kg/kkg (4.0 lb/1000 Ib) anhydrous soap
Suspended Solids -3.4 kg/kkg (3.4 lb/1000 Ib) anhydrous
soap
Oil and Grease - 0.3 kg/kkg (0.3 lb/1000 Ib) anhydrous
Best_Ayailable_Technology_Econcmically Achievable __Guide lines
Please refer to guidelines in Table 7-2 at beginning of this Section.
2Q_2_-_AIR - S03 SULFATION AND SULFONATION
Ec^njO^
When vapor phase sulfur trioxide is used in sulfonation and sulfation
processes, regardless of whether or not the vapor S0^3 is diluted with
nitrogen or air, three distinct types of feed and reactions for the
application of sulfur trioxide need to be considered. The three feed
stocks involved are 1) alkyl benzenes; 2) alpha or branched chain
olefins; and 3) lauryl, fatty and/or ethoxylated alcohols. Please refer
to figures 35-37.
The sulfur trioxide used in these three processes using different
reactants may be prepared in three different ways. Altnouth other
methods of preparation are also possible, the following are those used
commercially. The first process for producing sulfur trioxide is that
of sulfur burning. In this process a liquid sulfur is vaporized and
burned, usually in two stages, with air to form a sulfur trioxide-air
mixture which can be fed directly in vapor form to the
sulfonation/sulf ation unit.
Another source of sulfur trioxide is that derived from high strength
oleum. In this process, 65-70 percent oleum is the purchased feed
component. It is heated in a reboiler operation to produce anhydrous
vapor S03_, as the concentration of the oleum is reduced to a 20 percent
or even a lower level. The S03 vapor is then diluted with air or
nitrogen as the feed stream to the reactor. The sulfuric acid remaining
152
-------
is then sold or transferred to a sulfuric acid manufacturer for
reconstitution to the higher 65-70 percent oleum level.
A third way of obtaining sulfur trioxide is by purchasing stabilized
liquid sulfur trioxide. This source of sulfur trioxide can be brought
in by tank cars or by an over- the-fence arrangement. It is of 99
percent or higher purity and in a stabilized form of one of its phases.
It is stored over an inert gas, usually nitrogen, in order to preserve
its stability in storage while in the liquid state.
For the purpose of costing, S03 has been assumed to be manufactured by
burning sulfur. it was further assumed that this does not add to the
water effluent waste loading, since most of the losses from carrying out
the preparation of S03 would be in the vapor phase and therefore
concerned only with problems of waste blowing into the atmosphere, if
any.
In a sense, the purchase of sulfur trioxide in its stabilized form would
lead to no different degree of air or water effluent waste. In the case
of sulfur trioxide production from high concentrations of oleum, then a
reboiler reactor, which produces the S03 vapor, does lead to a liquid
stream of sulfuric acid. However, as stated earlier, this is generally
sent over the fence or even shipped for reconcentration to the original
strength oleum. It thus presents no added water effluent flow except
for spills and accidental incidents.
When an alky1-benzene is employed as the raw material for reaction with
sulfur trioxide, as well as in the other reactants mentioned above,
there are side reactions which occur if sufficient heat removal and
close temperature control is not attained. Therefore, generally useful,
is the recycle of the cooled intermediate state alkyl-benzene sulfonic
acid or the alkene sulfonic acid or the lauryl alcohol sulfuric acid
back into the staged reaction loop, after cooling. In this way and with
good temperature control, preferably in the range of 60-80 C (140-176
°F), high yield of the desired products may be obtained.
In the case of alkyl-benzene as a feed stock, it is desired principally
to obtain the para-substituted product rather than those in other
positions on the benzene ring. If high temperatures at the surface of
contact is unfortunately reached, there is a strong tendency for both
disproportionation and ring isomerization in the case of alkyl-benzene
feed stock. In addition to the desired mono-substituted alkyl-benzene
sulfonic acid, a fair amount of anhydrides of sulfonic acid are also
obtained. These are essentially the anhydride of two alkyl-benzene
sulfonic acid molecules. These anhydrides must be hydrated with water
or otherwise reacted, in order to produce alkyl-benzene sulfonic acid of
good quality. This reaction to produce the anhydrides is the result of
the affinity for sulfur trioxide in the liquid phase to react with
water, extracting it from combined hydrogen and hydroxyl groups, to form
sulfuric acid. The sulfuric acid in the water phase cannot be reverted
but must instead be decomposed by the dilution or hydration with added
water in a separate step.
153
-------
When either an alpha olefin or a branched chain olefin is to be
sulfonated, several side reactions occur which diminish the product
quality and result in by-products which must be dealt witn. The
principal reaction besides that cf the sulfonation of the olefin to
produce the alkene-sulfonic acid in the terminal bond position of the
olefin, is that of bond migration where the sulfur trioxide reacts and
moves along the chain, so that no longer does one obtain a terminal
sulfonic acid product but one which is branch chained at the position of
the sulfur trioxide addition.
Another reaction forming undesirable by-products that occurs with sulfur
trioxide and an olefin is that of the formation of sultones, which are a
cyclyzed form of the thiolone. These appear generally in three of their
most stable forms, that is, alkyl- propane sultone, alky 1-butane sultone
and also octane-alkyl sultone, all of which must first be destroyed
before a useful product can be obtained.
The conversion of sultones is accomplished by direct reaction with
caustic soda or sodium hydroxide, which produces the sodium
hydroxy-sulfonate of the alkene product together with a sodium alkene
sulfonate in stoichiometric proportions. The normal reaction product,
alkene sulfonic acid is simultaneously neutralized with caustic soda to
form the desired sodium alkene sulfonate and water.
In the case of sulfation reactions ir. which an alcohol, an ethoxylated
alcohol or an ethoxylated phenol is used for sulfation with sulfur
trioxide, the product formed is an organic sulfuric acid. In this case,
the same by-products can occur as with oleum sulfation.
The reaction products from the alpha olefin or branched olefin must
first be neutralized to produce the desired sodium alkene sulfonates
before further hydration, whereas in the case of the direct reaction of
sulfur trioxide with alkyl-benzene, the neutralization can follow
hydration steps. Of course, an organic sulfuric acid requires no
hydration.
In all cases of these three reactions there is usually a holding tank
after a cyclone separation of vapor S0_3 that is unreacted, and the
liquid streams of product and sulfuric acid. For this reason the
holding tank provides not only additional residence time for the
completion of the formation of sulfonic acids or alkyl alcohol sulfuric
acid, but completes the reaction so .that a recycle stream can be
returned to the sulfonator or sulfator stage in order to get increased
heat transfer and diminish the possibility of double substitution of a
sulfonic acid group.
Some of these reactions are carried out simultaneously in certain
instances because alkyl benzene sulfonate and the fatty alcohol sulfates
are both often blended for a better balanced detergent. This blending
can best be done after the reaction loop but before the hydration and
neutralization steps, and leads to superior blended products.
154
-------
The neutralization of the reaction can be carried out with any alkaline
neutralizing agent depending upon the product desired. For example,
caustic soda, as earlier described, aqua ammonia, which will lead to the
formation of an ammonium salt; potassium, or even ethanol amines can be
used. In addition, when liquid detergents are being made, substances
such as low molecular weight alcohol, urea, toluene and/or xylene
sulfonates for hydrotropic agents can be also simultaneously made in
tandem operations and blended before hydration and neutralization.
The most feasible means of decreasing water effluent contaminants and
simultaneously of increasing the quality of the product, as it applies
either to a batch or a continuous system assumed in BPCTCA technology,
is the addition of dilution in the reaction step, increased agitation to
diminish temperature elevations as a result of the exothermal nature of
the reaction, or better contact between the vapor sulfur trioxide and
the liquid reactant phases. Additionally, a batch counter-current
process can be installed by utilizing two or more reaction loops, in
which the fresh sulfonic acid in the form of sulfur trioxide, is
introduced into the stream to the completion stage or holding stage of
the reaction in counter-current to the feed of the alkyl- benzene, the
olefin, or a fatty acid alcohol. Such a batch counter-current
arrangement is easily feasible and should be economically viable by the
addition of one or more small reaction loops for a second and even third
stage of the process.
Raw Waste Loadings
The following average raw waste loadings can be expected:
BOD5 - 1.9 kg/kkg (1.9 lb/1000 Ib) anhydrous product
COD - 3.7 kg/kkg (3.7 lb/1000 Ib) anhydrous product
Suspended Solids - 0.2 kg/kkg (0.2 lb/1000 Ib) anhydrous product
Surfactant - 1.8 kg/kkg (1.8 lb.1000 Ib) anhydrous product
Oil and Grease - 0.4 kg/kkg (0.4 lb/1000 Ib) anhydrous product
Best Available Technology Economically^Achievable Guidelines
Please refer to guidelines in Table 7-2 in this Section.
PROCESS 203 - S03 SOLVENT AND VACUUM SULFONATION
PROCESg 204_- SULFAMIC ACID SULFATIOK
PROCESS_205_- CHLQROSULFONIC ACID SULFATIQN
Best Available Technology Economically Achievable
Improved process control should reduce the waste loading.
155
-------
cop
3.0
3.0
5.0
Suspended
Solids
0.1
0. 1
0.2
Surfactant
0.1
0.1
1.5
°-ii_§
Grease
0.2
0.2
0.3
Raw Waste Load
The following average raw waste loads are expected (all values given in
kg/kkg, lb/1000 Ib of product produced).
BOD5
203 1.0
204 1.0
205 1.5
Please see guidelines in Tables 7-1 and 7-2 at beginning of Section.
PROCESS 207-~ SPRAY DRIED DETERGENTS
JAIR QUALITY RESTRICTION OPERATION^
Best, Available Technology Economically Achievable,and_Rationale
As discussed in Section VII, installation of tandem chilled water
scrubbers (one with high and one with lew detergent concentration) to
scrub the plume will enable meeting air pollution restrictions while
materially reducing the water effluent load.
Raw^Waste Load
The following average raw waste load is expected:
BOD5 - 0.6 kg/kkg (0.6 lb/1000 Ib) anhydrous product
COD - 2.5 kg/kkg (2.5 Ib/IOO'O Ib) anhydrous product
Suspended Solids - 0.7 kg.kkg (0.7 lb/1000 Ib) anhydrous
product
Surfactant - 1.0 kg/kkg (1.0 lb/1000 Ib) anhydrous product
Oil and Grease - 0.2 kg/kkg (0.2 lb/1000 Ib) anhydrous
product
Best_Avail.able Technology Economically Achievable Guidelines
Please refer to guidelines in Table 7-2 at beginning of this Section.
PFOCESS_208_-_LIQUID_DETERGENTS
PROCE55^21_1_Z_DETERGENT_BARS_AND, CAKES
Best Available Technology Economically Achievable and Rationale
156
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Guidelines recommendations for both processes were reduced on the basis
of expected greater control over product losses in washups and general
manufacturing.
Raw_Waste_Load
The following raw waste loads are expected (all values given in kg/kkg,
lb/1000 Ib of anhydrous product.)
BOD5 COD Suspended Surfactant oil &
Grease
208 0.5 1.5 ---- 0.5 ---
211 3.0 9.0 1.0 2.0 0.2
Best Availa bl e_ Technology Economically Achievable Guideline s
Please refer to guidelines in the Table 7-2 at the beginning of this
Section.
157
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SECTION XI
NEW SOURCE PERFOPMANCE STANDARDS
AND PRETREATMENT STANDARDS
Introduction
New source performance standards (NSPS), being that which would be
employed in a new source of manufacture, offers an opportunity to start
afresh in the design of production facilities. Reviewing candidate
processes for minimized effluents has produced no great surprises. Soap
and detergent making is a well established art. Still, a number of
relevant, substantive concepts for improvement have emerged as well as a
few fairly far from commercial realization. Bearing in mind the
necessity of being very practical, in the discussion of all newer
developments for NSPS, particular note has been made of the degree to
which each technique has been reduced to acceptable commercial practice.
The technology, in most categories, reflects the improvements developed
in best available technology economically achievable. The guidelines
for many of these subcategories will be the same for the two groups of
technology. To simplify study of the recommendations, the guidelines
are reported in tabular form with the processes given new limitations
and special consideration in the text noted by an asterisk. The sign a)
in the table indicates that the 1983 and new source guidelines are
identical. Please refer to the corresponding guidelines discussion in
SECTION X for extensions and exceptions recommended for the guidelines.
These exceptions are applicable to both sets of guidelines.
Following the discussion of specific process improvements for new source
performance standards is a review of process chemistry developments
which deserve further continuing study for ultimate improvements in low
effluent level products. As with all such "far out" developments, some
of the concepts have greater probability for success than others. They
are offered for the different perspectives they offer to this
sophisticated art of soap and detergent manufacturing and formulating.
159
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TABLE 8
N§.w_Source Performance Standards Guidelines
Note: All values reported are in kg/kkg (lb/1000 Ib) of anhydrous
product made in that category. For all categories the guidelines pH is
6-9.
Suspended Oil &
BOD5 COD Solids Surfactant Grease
Batch Kettle and
Continous Soap* 0.20 0.60 0.20 — 0.05
Fatty Acid By Fat
Splitting® 0.25 0.90 0.20 — 0.15
Soap From Fatty
Acid Neutrali-
zations 0.01 0.05 0.02 — 0.01
Glycerine Recovery
Concentrations 0.40 1.20 0.10 -- 0.04
Distillations 0.30 0.90 0.04 — 0.02
Soap Flakes And
PowdersS 0.01 0.05 0.01 — 0.01
Bar SoapsS 0.20 0.60 0.34 — 0.03
Liquid Soap® 0.01 0.05 0.01 — 0.01
Oleum Sulfation/
Sulfonation* 0.01 0.03 0.02 0.01 0.04
Air-S03_ Sulfa-
tion/Sulfonation* 0.09 0.40 0.09 0.09 0.02
SO3 Solvent and
Vacuum Sulfona-
tionS 0.10 0.45 0.01 0.10 0.02
Sulfamic Acid
Sulfation® 0.10 0.45 0.01 0.10 0.02
Chlorosulfonic
Acid Sulfation® 0.15 0.75 0.02 0.15 0.03
Neutrali zation
Of Acids® 0.01 0.05 0.03 0.02 0.01
Spray Dried
Detergents
Normals 0.01 0.08 0.01 0.02 0.005
Air Quality
RestrictedS 0.08 0.35 0.10 0.15 0.03
Fast
Turnaround® 0.02 0.09 0.02 0.03 0.005
Liquid Deter-
gentsS 0.05 0.23 0.005 0.05 0.005
Detergent Dry
Blending® 0.01 0.08 0.01 0.01 0.005
Drum Dried
Detergents® 0.01 0.05 0.01 0.01 0.01
Detergent Bars
and CakesS 0.30 1.35 0.10 0.20 0.02
160
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PROCESg DISCUSSION
SOAP_MANUFACTURE_BY_BATgH_KETTLE
Soap_Manufacture by Continuous Counter-Current^Process
There appears to be little economic driving force for the construction
of a totally new batch soap mar.ufacturing installation, from fats and
oils, in the united States in the foreseeable future. There will be
replacement of some pieces of equipment as maintenance demands. Soap
use is expected to hold constant at best. Particularly in tcilet bars,
there is continuing loss of soap volume to synthetic detergent bars
where the hard water problems are severe.
A totally new installation, starting with fats and oils, will most
likely be a continuous manufacturing process. Although initial capital
investment and operating costs are the lowest attainable, use of a
continuous unit entails the sacrifice of some manufacturing flexibility.
For example, changeovers are accomplished more conveniently and/or
economically with a batch kettle when it is desired to make a number of
different base soaps, each of which requires different fatty raw
materials input.
Technically, a continuous unit possesses two major advantages. It uses
very little water, thus minimizing the problem of waste water disposal.
Secondly, as the nigre is formed entirely in a solid state, its handling
is greatly simplified. In areas where there is little or no market for
the dark soaps derived from nigre, this is a distinct advantage. Please
refer to Figure 33 for process details.
Manufacturing operations still require preliminary fat refining and
bleaching, as shown in section 1012 of the schematic diagram for soap
manufacture by batch kettle. Therefore, the waste streams from this
process can be minimized only to the extenr described in best available
technology economically achievable. The volume of waste water currently
generated by the batch kettle process can be reduced about 80 percent.
Utilities are expected to run no more than 0.440 to 0.660/kkg (0.20 to
0.30/1000 Ib) of neat soap. Electricity use is somewhat increased by
the requirements of the turbo-disperser motors and those for the
centrifuge operations. This added cost would be approximately 0.220/kkg
(0.10/1000 Ib) of soap product according to best estimates.
A significant reduction in operating cost would be expected in the
substitution of the continuous processing for a batch kettle from
reduced labor requirements. Instead of labor in the range of eight to
ten men per shift for a kettle plant of circa 9 to 13.6 M kg (20 to 30 M
Ib) capacity per year or higher, it should be no more than two or pos-
sibly three men per shift for a continuous unit, representing a striking
reduction in labor costs. Through labor savings alone, capital
investment for a continuous soap process should be recovered within ten
years.
161
-------
Realizing that improvements in the clay treatment and vacuum bleaching
of the feed oils and fats are limited to the replacement of a barometric
condenser by a two-stage surface condenser, and that only good operating
cleanliness can further reduce the raw waste load, the best available
demonstrated control technology guidelines consider a small allowance
for wastes from fats and oils pretreatment but essentially none for the
continuous saponification process.
By the use of centrifugation, the soaps or fats can be effectively
separated from the salt and lye. Thus, all of these materials can be
reprocessed and it would appear that recommended guideline levels could
easily be met in the continuous saponification plant.
Raw_Waste_Load
The following average raw waste load can be expected:
BOD5 - 2 kg/kkg (2 lb/1000 Ib) anhydrous soap
COD - 4 kg/kkg (4 lb/1000 Ib) anhydrous soap
Suspended Solids - 2 kg/kkg (2 lb/1000 Ib) anhydrous soap
Oil and Grease - 0.5 kg/kkg (0.5 lb/1000 Ib) anhydrous soap
SOAP_FROM FATTY ACID NEUTRALIZATION
General
In BADTC technology the manufacture of soap by fatty acid neurralization
is regarded as the norm for the preparation of neat soap. It is
depicted in Figure 34. Data reported here is a combination of field
visits and contractor's engineering design parameters. Data from two
installations has been integrated with additional information found in
the literature.
BADTC_Technology - Soap Manufacture
The continuous process makes use of proportioning pumps with interlocks
and main control-interlocks for absolute rate of feeds flow, very
similar to that outlined in the continuous saponification process. In
this process turbodispersers are used which greatly enhance the con-
tacting efficiency between the water and fatty acid or oil phases of the
reactants. The reaction time is reduced to a matter of 10 to 15 minutes
total within the reactor and separation systems.
The quality of product made from such a continuous operation is
equivalent to or improved over that from the batch kettle. For example,
the batch kettle process will result in an average content of free
alkali, measured as Na20, of 0.5 percent to 0.75 percent,. In the case
of the continuous manufacturing operation (representing an average range
of all contractors' claims) the free alkali is reduced tenfold to
approximately 0.05 percent to 0.075 percent. Similarly, the salt
162
-------
content is reduced from 1 percent to 0.5 percent. The neat soap
produced from this reaction needs to be dried from approximately 35
percent water content to the desired level. The drying process is
considered separately.
Battery limit capital investment, including appropriate tankage for the
reactants, will cost approximately $500,000 for a 20 million pound per
year plant. Direct operating labor will approximate $60,000 per year
using standard labor costs. Appropriate maintenance and administration
costs would equal the direct labor costs. It is estimated that steam
consumption will amount to approximately $6,000 per year; electricity
approximately $10,000 per year, and cooling water approximately $2,000
per year for a 20 million pound per year installation. It must be
emphasized that this covers only the neutralization step for production
of neat soap from fatty acids.
BAR_SQAP - DRYING
The drying operation is no different than that in BATEA guidelines for
solid bar soap manufacture. A surface condenser is indicated for use in
place of the normal barometric condenser now generally utilizecl for soap
drying, especially when vacuum drying operations are carried out for
clear soaps.
The capital cost for the above drying operation (for the production of a
bar soap extrudate) is estimated at $200,000 for 9 M kg (20 M Ib) per
year of anhydrous soap capacity. Operating steam, electric and cooling
water costs are the same as those shown for best available technology
economically achievable.
SOLVENT PROCESS FOR SOAP MANUFACTURE
A process developed in the 1940*5 requires no water to make anhydrous
soap and dynamite glycerine.
In the Kokatnur process fats or oils dissolved in heated kerosene (260-
290C) (500-554F) are mixed under pressure with anhydrous caustic soda.
The reaction takes place in ten minutes and produces dynamite grade
glycerine. After drawing off the glycerine, the remaining mixture is
released into an expansion chamber where evaporation of the kerosene
yields anhydrous soap. The process has the following advantages:
1. Very short reaction time.
2. Use of kerosene prevents charring.
3. Absence of water reduces heat requirement.
4. Dynamite grade glycerine and anhydrous soap are obtained directly.
One major defect of the process is that there is no refining stage and
traces of kerosene are left in the soap, making it impossible to market
163
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the product for toilet bar use. Without further refinement the soap is
suitable only for limited industrial uses.
201 - OLEUM SULFATION AND SULFOKATION
Extensive contractor data indicates that, with good engineering design
of the reactor and a minimum residence time prior to neutralization, the
levels proposed for raw waste load car. fce readily met by a continuous
process plant.
Compared to those for batch or semi-batch reverse feed systems, capital
investments for a continuous process are estimated to be lower by
$66/kkg ($30/1000 Ib) of annual capacity. Operational savings are
possible in the form of reduced labor costs, lower consumption of
utilities, and higher conversion of feedstocks (0.8 to 1.0 percent) to
products.
The continuous process is adaptable to almost any size installation from
900 thousand kg (2 million Ib) per year upward. Please refer to Figure
35.
Raw^Waste Loadings
The following average raw waste load can be expected:
BOD5 - 0.1 kg/kkg (0.1 lb/1000 Ib) anhydrous product
COD - 0.2 kg/kkg (0.2 lb/1000 Ib) anhydrous product
Suspended Solids - 0.2 kg/kkg (0.2 lb/1000 Ib) anhydrous
product
Surfactant - 0.1 kg/kkg (0.1 lb/1000 Ib) anhydrous product
Oil and Grease - 0.4 kg/kkg (0.4 lb/1000 Ib) anhydrous
product
S02 AIR-SQ3 SULFATION AND SULFONATION
BADTC guideline recommendations are based on process chains shown in
Figures 35, 36 and 37. The process chain involves the reaction,
hydration, neutralization and finishing steps for production of
alkylated aromatics.
Neutralization
NSPS guideline recommendations are based upon technology illustrated in
Figures 35-37 related earlier, each covering a separate feed stock,
i.e., alkyl aromatics, olefins and alcohols. The process variations
reflect the particular chemical reaction characteristics of the feed
stocks.
164
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In an integrated plant utilizing products containing derivatives of all
three feed stocks, superior blended products can be made by combining
the reaction products after the reaction loop but prior to the hydration
and neutralization steps. This procedure is particularly applicable to
the blends of alkyl benzene sulfonate with fatty alcohol sulfates.
Performance of a new installation based upon continuous
sulfonation/sulfation is expected to be improved moderately over already
installed batch or batch counter current systems. The form of sulfur
trioxide used will not influence the effluent water quality.
The cost depicted and guaranteed by a supplier shows utility demands as
follows; electricity 0.9 to 1.1iZ/kg (0.4 - 0.50/lb) of active material
from the reaction; cooling water requirements of 0.1 - 0.20/kg (0.05 -
0.100/lb) of active product. The initial capital cost for this
installation relates of course to plant size with economy of scale
favoring large plants. For plants in the size range of 13.6M kg per
year (30M Ib per year) of active ingredient, and based upon a 92 percent
stream factor, capital amounts to $88-110/kkg ($40-50/1000 Ib) annually
product capacity.
Use of stabilized liquid sulfur trioxide is assumed. If sulfur trioxide
is produced by sulfur burning, this is considered to be a separate unit,
and the economics and the justification covered in the water effluent.
Raw Waste Load
The following raw waste load can be expected:
BOD5 - 0.9 kg/kkg (0.9 lb/1000 Ib) anhydrous product
COD - 2.7 kg/kkg (2.7 lb/1000 Ib) anhydrous product
Suspended Solids - 0.9 kg/kkg (0.9 lb.1000 Ib) anhydrous
product
Surfactant - .0.9 kg/kkg (0.9 lb/1000 Ib) anhydrous product
Oil and Grease - 0.2 kg/kkg (0.2 lb/1000 Ib) anhydrous
product
PRETREATMENT REQUIREMENTS
In this section of the report those pollutants capable of disrupting, or
likely to disrupt, the operation of a publicly owned waste water
treatment plant are cited. It should be fully understood tnat it is not
the intent to provide limits or other standards which would in effect
supplant any sewer use ordinance developed and now being enforced by a
central authority. In fact, every authority that owns a collection and
165
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ON
o\
SECTION X and XI
LEVEL II TECHNOLOGY
and
LEVEL III TECHNOLOGY
SCHEMATIC FLOW DIAGRAM - 201 and 206
CONTINUOUS DETERGENT SLURRY PROCESSING PLANT
HIGH-ACTIVE ALKYLATE SULFONATION WITH OLEUM : FEED A_
LOWNa2SO4 CONTENT
REACTION
COIL
Modified 201-A: SULFONATION
ALKYLBENZENE
FROM STORAGE
Cooling
Water
SULFONATION
COOLER
PROPORTIONING
PUMP
WATER-
COOLED
MIXING
PUMP
Cooling |~
Water —•'
SETTLER
DILUTION
COOLER
OLEUM
FROM
STORAGE
WATER
i
T
SPENT
ACID
MIXING
PUMP
206-A: Neutralization
NEUTRALIZED
DETERGENT
SLURRY
Cooling
Water
NEUTRALIZATION
COOLER
\\n
Water Cooled
MIXING
PUMP
ALKALI
-------
SCHEMATIC FLOW DIAGRAM— 201 MODIFIED
CONTINUOUS DETERGENT SLURRY PROCESSING PLANT
FATTY ALCOHOL SULFATION WITH OLEUM : FEEDS B and C
FATTY ALCOHOL
FROM STORAGE
OLEUM
FROM
STORAGE
PROPORTIONING
PUMP
SULFATION
COOLER
MIXING
PUMP
T
NEUTRALIZATION
COOLER
MIXING
PUMP
NEUTRALIZED
->• DETERGENT
SLURRY
Cooling
Water
ALKALI
Modified: 201-B and C : SULFATION
201-B and C : NEUTRALIZATION
FIGURE
32
-------
00
SECTION XI
LEVEL III TECHNOLOGY
108: SOAP MANUFACTURE BY CONTINUOUS SAPONIFICATION
ion RECEIVING
STORAGE THMtSfEB
101? FAT REFINING
AND BLEACHING
FATTY OILS
COCONUT. TALLOW
CAUSTIC SOOA
STEAM
SALT —
DILS
-ED
OILS
OILS
CIDS ^
OSIN
0 FATS
lit STAGE
KILL
'
1 |
L_
TURBO
DISPER
SEH
t
S
c
t
2nd STAGE
STRONG
CHANGE
1
TURBO
DISPEH
SER
.PENT LYE AND
.LYCERINE
f 1
•
3rd STAGE
WEAK
CHANGE
TURBO
fc DISPER
, SER
V
"
T— J
r
CENTRIFUGE
t ,
^
I
4th STAGE
FITTING
BALANCE
NE
*• TO
NEAT SOAP
FROM
REACTION
NEAT SOAP
TO DRYING
MAKEUP
DRY SALT
LYE. GLYCERINE,
SALT and WATER
3
-------
SECTION XI
LEVEL III TECHNOLOGY
103 Modified: SOAP BY CONTINUOUS FATTY ACID NEUTRALIZATION
WATER RECYCLE I
• MATCB V
FATTY ACID
RECYCLE
1031 RECEIVING
STORAGF-TRANSFET
MAKEUP
WATER
GLYCERINE
SODIUM
INTERLOCKED
ACIDS
CSODA
UM HYDROXIDE
CHLORIDE
INE
CARBONATE —
- «*•
1 -*•
~~1
t
Ux
1
i i
1 1
1
1 Y^
^•^~
LEAKS SPILLS, STORM
RUNOFFS, WASHOUTS
IOJIO2
PROPORTIONING PUMPS
r
i — i
i
•i_i —
r-1
•L_
J
.
r
*>- . ,f
1 r-
1
SEQUENTIAL
i . OR
/ TANDEM
VENT OPERATION
t
2nd STAGE
Q
TURBO
DISPERSER
PU
\
_ _
IMP
Carbon
Dwxtd*
V«nt
t
co2
SEPA
REACTION TURBO
TOWER DISPERSER
„ .
Section 1062-Modified:
NEAT SOAP DRYING: FOR BAR SOAPS
CONDENSATE
TO BAR SOAP
MOLDING
TO
ATMOSPHERE
O
u>
-------
SECTION XI
LEVEL III TECHNOLOGY
COMBINED PROCESSES
Modified 202 : SO, - SULFONATION / SULFATION PROCESSES - CONTINUOUS
O
AND
Modified 206 : NEUTRALIZATION OF SULFONIC OR ALKYL SULFURIC ACID PROCESSES - CONTINUOUS
TO SCRUBBERS
202A and 206A : SCHEMATIC FLOW DIAGRAM
Modified ALKYL BENZENE SULFONATION
Reaction: 202 A Section
ALKYL
BENZENE
S03-AIR
O
d
g
DIGESTOR
HYDRATOR
WATER
SULFONATION
DIGESTION
HYDRATION
NEUTRALIZATION: 206 A Section
-*, PRODUCT
CAUSTIC SODA
NEUTRALIZATION
-------
SECTION XI
LEVEL III TECHNOLOGY
SCHEMATIC FLOW DIAGRAM
202 C and 206 C: Modified - Combined
FATTY ALCOHOL SULFATION : WITH SO.
Reaction : 202 C Section
FATTY
ALCOHOL
Neutralization : 206-C Section
TO SCRUBBER
S03-AIR
O
u>
— PRODUCT
HEAT
EXCHANGER
PUMP
Cooling
• Water
CAUSTIC
SODA
-------
SECTION XI
LEVEL III TECHNOLOGY
SCHEMATIC FLOW DIAGRAM - COMBINED 202B and 206B
ALPHA - OLEFIN SULFONATION WITH SO,
Reaction: 202 B Section
Neutralization : 206 B Section
ALPHA
OLEFIN
•-J
NJ
SO,-AIR
O
c
P*>
M
REACTOR
SULFURIC ACID
CYCLONE
DEMISTER
PUMP
HYPOCHLORITE
BLEACH
PUMP
BLEACH
AND
HMIX
TANK
PRODUCT
CAUSTIC
SODA
-------
treatment system should have an up-to-date sewer use ordinance which
would enable it to regulate the types and quantity of industrial wastes
admitted to its system. The purpose of this section is to point out
possible problem areas and indicate applicable control measures.
With the exception of dissolved mineral salts there is essentially no
pollutant in the wastes from soap and detergent manufacturers that
cannot be removed at high levels of efficiency in a central plant.
Fats and Oils
Fats and oils from soap plants are readily degradable. Whenever
excessive fats, oils or greases are discharged, or whenever a safeguard
against such a discharge is required, the waste should be passed through
a gravity type separator prior to discharge to the central system. This
type of pretreatment serves to remove up to 90 percent of the free oils
which are the primary source of problems in both sewers and the
treatment plant.
As previously discussed, the well-designed fat trap is similar to a
primary clarifier in a municipal plant. An appropriate size for a large
soap plant would be rated 2078 1/day/l sq m (600 gallons/day/square
foot). Residence time should be about 1 hour. Such a far trap, with a
radial flow to the perimeter discharge weir and a rotating scraper arm
which moves the fat layer in front of the arm and thence into a well,
will do an excellent job and provide essentially complete removal.
The underflow from such a fat trap will have a high treatable
concentration of biodegradable organics. in one of the soap plants
observed in this study a reserve of the underflow is retained in tanks
to be used as a feed for the biological treater when only a few units of
the plant are operating.
If the pollutant is a low molecular weight mineral solvent which has a
low water solubility the same treatment mechanism can be employed. The
captured material should be burned or processed for reuse. The non-
flotables and the liquid phase should be passed on to the central
treatment plant.
The efficiency of the fat trap must be maintained and routine
inspections should be made by the proper authorities.
Fats and Oils - Deterqent_Plants
Detergent plants will have oil and grease effluents more like the
hydrocarbons encountered in the organic chemical industry; namely, they
will be of fossil or petroleum origin rather than from natural . fats
These hydrocarbons are not as readily degraded as those originating from
the soap plant. The only analytical method, as described in Standatd
Methods, makes no differentiation between the two types of hydrocarbons
Jntil such a test can be devised it would be unfair to set a standard
Dased on the least degradable product and make the more degradable
product conform to it. Additionally, from am economic standpoint it is
173
-------
most important to make a differentiation in treatability. The problem
is accentuated in that the industrial detergents will probably contain
more hydrocarbons extracted in the hexane extractable test that are
difficult to degrade than will the household detergents.
Zinc
Concentrations of zinc which could lead to problems at the central
facility have not been found in the waste water examined or in the data
analyzed. The best information available would indicate that zinc
concentrations of between 5 and 100 mg/1 in the biological portion of
the central plant could slow the rate of assimilation. Therefore, any
concentration of not more that 5 mg/1 would appear to be a satisfactory
process effluent level. The observed values have been less than 4 mg/1.
the relationship of zinc to the activity of nitrifying bacteria is under
study in EPA. The results could have an effect on this standard.
Should a zinc problem arise, pretreatment employing alkaline
precipitation is the most effective means of reducing zinc levels to
satisfactory concentrations in process effluent. This should be carried
out at pH values between 8.5 and 9.5 in the coagulation unit and at
surface loadings of 1627 1 - 20377 1/sg m (UOO-5000 gpd/sq ft) in the
sedimentation unit. The sludge should be dewatered and incinerated or
dried prior to disposal as a solid waste.
Industrial Cleaners
A number of soap and detergent manufacturers studied produce industrial
cleaners which contain phosphoric and hydrofluoric acids; and organics
such as chlorinated benzenes. The implication of the first two
substances is clear and whenever they are used, strict in-house control
steps should be excercised to control their discharge. The problem of
chlorinated organic discharge is potentially more serious. These
materials used in such applications as acid cleaners are moderately to
highly toxic to man and may have a deleterious effect on waste treatment
plants and on receiving waters. It is expected that treatability of
these compounds is being studied by the industries manufacturing them.
It is suggested that further definition of their impact,, and discussions
of in-house and pretreatment control measures await the completion of
those studies.
174
-------
SECTION XII
ACKNOWLEDGEMENTS
The Environmental Protection Agency wishes to acknowledge the
contributions to the project by Colin A. Houston & Associates, Inc
Mamaroneck, New York. Messrs. Colin A. Houston, Frederick C. Herot
Charles H. Daniels and Ms. Susan M. Weisman, with the able assistance of
their consultants Mr. George C. Feighner, Dr. Allen W. Fleer and Mr
Robert W. Okey, conducted the detailed technical study and drafted the
initial report on which this document is based.
Because of the wide-ranging scope of the study, there was occasion to
call upon many individuals and organizations for assistance ^n the
course of bringing it to completion. Many people, both as individuals
and as members of various organizations, responded with the utmost
courtesy and generosity. we regret that space does not permit their
individual citation, but the debt owed to each and every one of them is
gratefully acknowledged.
Throughout the country, soap, detergent and fatty acid producers, large
and _ small, graciously assisted in providing process information and
opening up their plants to detailed study and sampling. Three trade
associations performed valuable liaison functions in making the prelect
a truly cooperative one; the soap and Detergent Association, the
hemical Specialties Manufacturers Association, and the International
sanitary Supply Association.
Special help was received from members cf the Environmental Protection
"lowfrd inrh*!?10n? „"; IV-T V' VI and mi' AS an exai"Ple< Mr- William
-loward, Chief, Industrial Waste Section, Region IV, actively
Contributed to all stages of the project, including participation in the
in- plant sampling program. Many of the accomplishments of the samplina
•J^rLT a^ri?UKable t0 the assistance ^d analytical suppor?
.eceiyed from the laboratory of the Division of Water Pollution control,
.ouisiana _ Wildlife and Fisheries Commission, Baton Rouge, Louisiana and
:he following Environmental Protection Agency laboratories: Analytical
Duality control Laboratory, Cincinnati, Ohio; Robert s. Kerr Water
******** Center. Ada, Oklahoma; and the Regional Laboratories in Athens,
Borgia; Evansville, Indiana; Annapolis, Maryland and Kansas City
. lasting indebtedness is acknowledged to those in the Environmental
'rotection Agency who assisted in the project from inception of the
.tudy _ through preparation and review of the report. Especially
eserving recognition are: Ms. Jan Beale, John Ciancia, Ms. Patricia
•o™n'R;, MSn ?al '» MS^ Frances Hansborough, Richard Insinga, Thomas
;opp, Ray Mcoevitt, Ronald McSwinney, David Mears, John Riley, MS. Jaye
wanson and George Webster. "«./<=
175
-------
SECTION XIII
REFERENCES
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2. Air Plastics, Inc. Cincinnati, Ohio. Pollution
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(1973)
3. Air Pollution Control District, county of Los Angeles,
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4. Altman, Philip L. and Dittmer, Dorothy S. Environ-
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5. American Chemical Society. 1972-1973 Lab Guide. ACS.
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6. American Public Health Association. Standard Methods
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7. Appraisal of Granular Carbon Contacting. Phase III
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8. Badger, W. L. and McCabe, W. L. Elements of Chemical
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9. Balalrishnan, S., Williamson, D. E., and Okey, R. W.
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10. Ballestra, M. Sulfonic Acids Neutralization with Sodium
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699 (1965)
11. Bell, Doug. Report of Office of Air Programs.
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12. Benedikt. Chemical Analysis of Oils, Fats and Waxes.
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177
-------
13. Benoit, R. J. and Okey, R. w. Effect of Presulfi-
dation on the Cotreatment of Plating Waste and
Domestic Sewage by Activated Sludge. Report to
Connecticut Research Commission. (1970)
14. Black, J. F. Radiochemical Production of Sulfonates
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U. S. Patent 3,324,387. (1967)
15. Black, J. F. Radiation Source for Sulfonatlon Using
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Colgate Palmolive Company. U. S. Patent 3,346 505.
(1967)
17. Blinoff, V. Sulfate Neutralization with Sodium Bi-
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Patent 2,975,141 (1961)
18. Ballestra, SPA. Manufacture of Synthetic Detergents.
Household and Personal Products Industry, pp 49-50.
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19. Bord, R. S. A Study of Sludge Handling and Disposal.,
USDI. FWPCC. May (1962)
20. Brooks. R. J. and B. J. Use of Stabilized Sulfur
Trioxide in Sulfonation. Chemithon Corp. U. S.
Patent 3,259,645. (1966)
21. Brooks, R. J. Improved Process for Sulfonation Using
Sulfur Trioxide. Chemithon Corp. U. S. Patent 3,350,
428 (1967)
22. Bureau of the Census. 1967 Census of Manufactures.
Concentration Ratios in Manufacturing, Part 3: Employ-
ment, Payrolls, capital Expenditures and Other General
Statistics. Bureau of the Census. June (1971)
23. California Water Quality Control Board. Detergent
Report, state of California. Sacramento, Califor-
nia. (1965)
24. ARCO Chemical Company. Description of Process for
Manufacture of Soft Detergent Alkylate. Glenolden,
Pennsylvania.
25. Chemical Engineers Handbook. McGraw Hill Company.
4th Edition. (1963)
178
-------
26. Chemiton Corp. Oleum Sulfoliation Process Equipment.
Brcshure. Seattle Washington. (1968)
27. Chemithon Corp. S03_ Detergent Process Equipment.
Proshure. Seattle, Washington. (1968)
28. Chemical Week. 1973 Buyers' Guide Issue. McGraw
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29. Cross, C. F. and Dreyfuc, C. Low Temperature Catalytic
Alcoholysis. British Patent 125,153. (1919)
3C. Cutler and Davis. Detergentry, Theory and Test Methods.
1st Edition, part 1. Mafcel Dekker, Inc., N. Y. (1972)
31. Cyrus, William Rice & company. The Cost of Clean Water
and its Economic Impact. Projected Waste Water Treat-
ment Costs in the Organic Chemicals Industry. Volume
IV. U. S. Dept. Of Interior, Federal Water Pollution
Control Administration. Washington, D. C. January 10
(1969)
32. Davidsohn, A. Detergents Powders via New Process.
Soaps, Cosmetics, Chemical Specialties, pp 27-42.
August, (1972)
33. Doss. Properties of Fats, Fatty Oils, Waxes, Fatty
Acids and Salts. The Texas company. (1952)
34. Dreger, E. E. Low Temperature Catalytic Alcoholysis.
U. S. Patent 2,383,596. (1945)
35. Dugan, Patrick R. Biochemical Ecology of Water Pollu-
tion. Plenum Press, N. Y. (1972)
36. Dun 6 Bradstreet, Inc. A Study of Pollution Control
Practices in Manufacturing Industries. Part I: Water
Pollution Control. Research Services Dept. Dun &
Bradstreet. June (1971)
37. Eckey, E. W. Hydrolysis. Encyclopedia of Chemical
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38. Eckey, E. W. Hydrolysis. U. S. Patent 2,378,005.
(1945)
39. Eckey, E. W. Vegetable Fats and Oils. ACS Monograph
123. (1954)
40. E. F. Eldridge. Industrial Waste Treatment Practice
Me Graw Hill, New York (1942)
179
-------
41. Emmett, P. H. Physical Organic Chemistry. John Wiley
& Sons. (1940)
42. Fieser, Louis R. and Mary. Advanced Organic Chemistry.
Rheinfold Publishing Company, New York.
43. Fieser, Louis F. and Ruth. Stercid Chemistry. Rhein-
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45. Hoffman, E. L. and Quigley, Ralph E. Flotation of Oily
Wastes. Proceeding of 21st Industrial Waste Conference,
Purdue University, Lafayette, Indiana. pp 527. (1966)
46. Hovious, J. C. et al. Anaerobic Treatment of Synthetic
Organic Wastes. For Office of Research and Monitoring,
Environmental Protection Agency. Project No. 12020 DIS.
January (1972)
47. Industrial Engineering Handbook. Equipment and
Facilities. 3rd Edition, Section II, pp 26-115.
H. B. Maynard, Ltd. (1971)
48. Jamieson, Z. Vegetable Fats and Oils. ACS Mono-
graph 58. (1943)
49. Kaempfe, G. Acidolysis of Glycerides. pp 1009. Far-
ber - Zeitung 40. (1935)
50. Karrer, P. Organic Chemistry. Nordeman Company,
New York. (1938)
51. Lewkowitsch. Chemical Technology and Analysis of
Oils, Fats and Waxes. Volume II. (1922)
52. Lohr, J. W. Alcohol Sulphates from Alcohols and Un-
diluted Sulfur Trioxide. Andrew Jergens company. U. S.
Patent 3,232, 976 (1966)
53. Marquis, D. M. et al. The Production of Alpha-Olefin
Sulfonates. Hydrocarbon Processing 47, no. 3, pp 109.
Chevron Research Company. (1968)
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180
-------
56. Mills, V. Continuous Countercurrent Hydrolysis of Fats.
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3,248,413. (1966)
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181
-------
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182
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SECTION XIV
GLOSSAPY
ABS - An abbreviation applied to a family of closely related
branched side-chain benzene compounds formerly used as sur-
factants in household detergents. ABS is an acronym for al-
kyl benzene sulfonate.
Act - The Federal Water Pollution Control Act Amendments
of 1972, Public Law 92-500.
Aerobic - Growing only in air or free oxygen.
Aerobic Bacteria - Bacteria which require the presence of
free (dissolved or molecular) oxygen for their metabolic
processes. Oxygen in chemical combination will not support
aerobic organisms.
Alkalinity - A quantitative measure of the capacity of li-
quids or suspensions to neutralize strong acids or to re-
sist the establishment of acidic conditions. Alkalinity
results from the presence of bicarbonates, carbonates,
hydroxides, volatile acids, salts and occasionally borates,
terms of the concentration of calcium carbonate that would
have an equivalent capacity to neutralize strong acids.
Amalgamator - A large horizontal mixer used to blend per-
fume, dyes, fillers (titanium dioxide for whitening), and
other materials in the manufacture of soap.
Anaerobic Bacteria - Bacteria that do not require the pres-
ence of free or dissolved oxygen for metabolism. Strict
anaerobes are hindered or completely blocked by the presence
of dissolved oxygen and in some cases by the presence of
highly oxidized substances such as sodium nitrate, nitrites,
and perhaps sulfates. Facultative anaerobes can be active in
the presence of dissolved oxygen but do not require its
presence. See also aerobic bacteria.
Anaerobic Decomposition - Reduction of the net energy level
and change in chemical composition of organic matter caused
by microorganisms in an anaerobic environment.
Antioxidants - Phenolic and amino compounds which inhibit
oxidation of organic compounds.
Atmosphere - Unit of pressure. One atmosphere is normal
atmosphere pressure.
183
-------
B§jrometric_Conderij5er ~ A system of toth chilling vapors
into the liquid state from a gaseous state and reducing
flowing down a vertical pipe with considerable velocity.
Identical to the laboratory aspirator, which depends upor.
the Venturi effect tc create a vacuum .
s ~ ^n considering plant construction ^r.d
costs, an arbitrary boundary between essential process
units and supporting facilities. Customarily within bat-
tery limits are reactors, stills, mixers, drir-rs, and
fabricators. Usually outside battery limits are power
plants, cooling towers, sewage and water ^reatmenr,, raw
material and proiuct storage, laboratory and office buildings
and roads,
Treatment required for new sources as defined by Section
306 (a) (2) of the Act. Level III.
Treatment required by July 1, 19P3 for irduGtrial discnargas
to surface waters as defined by Section 301 (b) (2) (A) ot
the Act. Level II.
Best_Practj cable Control, Technoloay^cuzrerrly^ Avail able
(BPCTCA) - Treatment required by July 1, 1977 for industrial
discharges to surface waters as defined by Section 301 (b)
(1) (A) of the Act.
Biological CoQling^Tower - A cooling tower which is seeded
with microorganisms and fed with nutrients in which biological
degradation of organics occurs.
Biological _Oxidation - The process whereby, through the
activity of living organisms in an eercbic environment,
organic matter is converted to more biologically stable
matter.
BioLo2icaJ__StabJJJ.zation ~ Reduction in the net energy level
of organic matter as a result of the metabolic activity of
organisms.
Biol02ical_Treatment - Organic waste treatment in which bac-
teria and/or biochemical action is intensified under con-
trolled conditions.
Blgwing_Tower - See spray tower.
184
-------
BOD5 - Biochemical oxygen demand. An indirect measure of the
concentration of biologically degradable material present in
organic wastes. It is the amount of free oxygen utilized by
aerobic organisms when allowed to attack the organic matter
in an aerobically maintained environment at a specified
temperature (20°C) for a specific time period (five days).
It is expressed in milligrams of oxygen utilized per liter
of liquid waste volume (mg/1) or in milligrams of oxygen per
kilogram of solids present (mg/kg=ppm=parts per million parts)
- Inorganic salts (usually) which augment the
cleansing^or dirt-suspending power of a soap or detergent;
i.e., sodium silicate, sodium carbonate, carboxy methyl
cellulose, phosphates, etc.
gapital_Costs - Financial charges which are computed as the
control. The cost of capital is based upon a weighted aver-
age of the separate costs of debt and equity.
i£ ~ Sodium hydroxide, caustic soda.
s - Those separate and identifiable steps taken in the
nanufacture of kettle boiling soap.
^h§2Li2§.l_Qxidation - Oxidation of organic substances without
Benefit of living organisms. Examples are by thermal combus
:ion or by oxidizing agents such as chlorine.
=IlY. ~ Alumino silicate minerals.
^I°.sed_SoajD - That single phase of soap and water having a
:reamy consistency while in the hot, agitated state.
:gD - Chemical Oxygen Demand. An indirect measure of the
>iochemical load exerted on the oxygen assets of a body of
*ater when organic wastes are introduced into the water.
'Ql JLFr ame goag - A type of soap produced by solidification
>y cooling and slicing into bars.
n§ate - The product resulting from a vapor condensing.
[22iiS2_Water_Blowdown - Whenever cooling water is reused
nd run over atmospheric contactors (in turn cooled by am-
dent air) there is a buildup of contaminants. Periodically
.t is necessary to dilute them or treat the cooling water to
blow down" or rid the system of the concentrated contaminants
185
-------
Crutcher - A cylindrical vessel of 681 - 2270 kg (1500 -
5000 Ib) capacity in which soap or synthetic surfactants
are mixed with builders prior to drying. It is often steam
jacketed.
De-aerator - A piece of equipment for removing air dissolved
or suspended in a fluid.
Detergent - Technically, any cleaning agent, including ordi-
nary soap, the new "synthetic" granules and liquids, many
alkaline materials, solvent, or even sand when used for
scrubbing, whether used in the home or in industry. In
popular speech, the term "detergent" is generally applied
to packaged cleaning products based on a surface active
ingredient such as ABS or LAS. Its cleaning power is re-
tained in hard water, contrary tc the performance of soap.
pissolved Oxygen - The oxygen dissolved in sewage, water,
or other liquid, usually expressed as milligrams per liter
or as per cent of saturation.
gffluent - The outflow of a sewer; a waste waterstream from
a manufacturing process or plant.
Evagorator - A unit in which liquids are converted to gas.
Fat - Glycerol esters of long chain fatty acids of animal
or vegetable origin.
Fat_Refining - Purification of fats by treatment with clay,
caustic, etc.
Fat Splitting - Various processes for hydrolysis of fatty
triglycerides to fatty acids and glycerine.
Fatty Acid - Naturally occurring straight chain carboxylic
acids which usually occur as triglyceride esters (fats).
Fatty Oil - Triglycerides which are liquid at room temperature.
Fitting Change - Also called pitching or finishing change,
is the final step in soap making in which clear water is
mixed with the soap to separate the neat soap from the
nigre.
Foots - The residue of refining fats or oils which contain
color bodies, insolubles, suspended matter, etc.
Full_Boil Process - Soap making where the neat soap is com-
pleted in the kettle and the by-product glycerine drawn off.
186
-------
Ji£§i§ ~ Tne residue remaining from any processing unit
after drawing.
Kil ling_Change - The first step in soap manufacture where
fresh fat is brought into contact with a lye solution.
The start of the saponif ication process.
LAS - A new surfactant in which a straight chain hydro-
carbon has been joined to the benzene ring. It has a high
rate of biodegradability.
i2w_Grade_Fatty__Acids - These are contaminated fatty acids
derived from recovery of scrap, acidification of nigre, and
contaminated fatty acid raw materials.
cess - A proprietary process for manufacture of
soap.
JDS/1 - Milligrams per liter.
N§-a.;t_Soa2 ~ An intermediate, completely saponified and puri-
fied soap containing about 20-30 percent water, ready for final
formulation into finished product.
N§.w_Source - Any building, structure, facility or installa-
tion from which there is or may be a discharge of pollutants
and whose construction is commenced after the publication of
the guidelines.
pi3£§ ~ The bottom layer which separates out in the last wash-
ing step of kettle boiling soap which contains the impurities
leading to poor color, odor, etc. Often contains 20 - 25 percent of
the kettle contents at that stage of the soap making and
possesses a soap content of 30 - 40 percent. The nigre can be
concentrated and salted out to yield a low grade colored
soap for sale.
go Discharge_gJ_Pollutants - No net increase (or detectable
?ross concentration if the situation dictates) of any para-
net er designated as a pollutant to the accuracy that can be
ietermined from the designated analytical methods.
Dil - Fats found in liquid form at room temperature. Gly-
^erol esters of long chain fatty acids.
)lgum - A solution of SO3 in sulfuric acid.
2£§I^i2ns_a^d_Maint.enance_costs - These required to operate
and maintain pollution abatement equipment. They include
.abor, material, insurance, taxes, solid waste disposal, etc.
187
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£H - 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 a tenfold change
in acidity and alkalinity.
Phenol - Class of cyclic organic derivatives with the basic
formula C6H5OH.
Plodder - A powerful homogenizer which resembles a sausage
grinde~r in design; used for the final processing of bar
soap wherein the occluded air is removed (under partial
vacuum) and the individual soap particles melded into one
continuous homogenous whole prior to being cut up into bar
stock.
Pollution - The presence in a body of water (or soil or air)
of substances of such character and in such quantities that
the natural quality of the body of water (or soil or air) is
degraded to a point where the water is rendered useless or
offensive to the senses of sight, taste or smell. Contami-
nation may accompany pollution. In general, a public health
hazard is created, but in some cases only economy or esthetics
are involved as when waste salt brines contaminate surface
waters or when foul odors pollute the air.
PI§±£§§£E!®II£ ~ Treatment provided prior to discharge to a
publicly owned treatment works.
Process, Water - In the manufacture of soap and detergent,
all waters that come into direct contact with the raw mater
ials, intermediate products, final products or contaminated
waters or air.
Ref ractor y_BOD5 - Organic substances which are slowly or
incompletely degraded by microorganisms.
Saponification - The hydrolysis cf an ester into its
corresponding alcohol and soap.
Secondary^ Treatment - Biological treatment provided beyond
primary clarification, usually aerobic activated sludge,
trickling filters or lagoon systems.
- - That soap making process wherein the
exact (stoichiometric) amount of caustic is added to fat
for saponification, and the soap is then run off into frames
or further processed without the benefit of removal of by-
product glycerine.
188
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Sewage - Water after it has been fculed by various uses.
From the standpoint of source it may be a combination of
the liquid or water-carried wastes from residences, office
buildings and institutions together with those from indus-
trial and agricultural establishments, and with such ground-
water, surface water and storm water as may be present.
Sewer Lyes - Waste sodium hydroxide from reclaiming of scrap
soap.
~ A chemical compound containing silicon, oxygen,
and one or more metals. In soaps and detergents, sodium
silicates are added to provide alkalinity and corrosion
protection.
._ - The process of heating a mixture of fats/oils
with caustic solution until the fatty ester is split and
the alkaline metal salt formed, glycerine being released in
the process. The step where sapor.if ication takes place.
Soda_Ash - Sodium carbonate.
Sp.ra_y_Dry_ing_Tower - A large vessel in which solids in
solution or suspension are dried by falling through hot gas.
Stabilizers ~ An additive which gives physical and/or
chemical stability to a formulation.
Still - A distillation apparatus.
Strong, Change - That step in the soap making process where
virgin, strong lye is added to the already saponified fat
to finally complete saponif ication of remnants of fat.
Surface-waters - Navigable waters; the waters of the U.S.
including the territorial seas.
Sweet Water - By-product aqueous glycerine from soap manu-
facture.
Synthetic Detergent - Chemically tailored cleaning agents
soluble in water or other solvents. Originally developed
as soap substitutes. Because they do not form insoluble
precipitates, they are especially valuable in hard water.
They are generally combinations of surface active agents
and complex phosphates to enhance detergency.
TDS - Total dissolved solids.
189
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TABLE
METRIC UNITS
CONVERSION TABLE
MULTIPLY (ENGLISH UNITS) by TO OBTAIN (METRIC UNITS)
ENGLISH UNIT ABBREVIATION CONVERSION ABBREVIATION METRIC UNIT
acre
acre - feet
British Thermal
Unit
British Thermal
Unit/pound
cubic feet/minute
cubic feet/second
cubic feet
cubic feet
cubic inches
degree Fahrenheit
feet
gallon
gallon/minute
horsepower
inches
inches of mercury
pounds
million gallons/day
mile
pound/square inch
(gauge)
square feet
square inches
tons (short)
yard
ac
ac f t
BTU
BTU/lb
cf m
cfs
cu f t
cu f t
cu in
OF
ft
gal
gpm
hp
in
in Hg
Ib
mgd
mi
psig
sq ft
sq in
ton
0.405
1233.5
0.252
0.555
0.028
1.7
0.028
28.32
16.39
0.555(°F-32)*
0.3048
3.785
0.0631
0.7457
2.54
0.03342
0.454
3,785
1.609
(0.06805 psig +1
0.0929
6.452
0.907
ha
cu m
kg cal
kg cal/kg
cu m/min
cu m/min
cu m
1
cu cm
°C
m
1
I/sec
kw
cm
atm
kg
cu m/day
km
)*atm
sq m
sq cm
kkg
yd
0.9144
hectares
cubic meters
kilogram-calor
kilogram calor
kilogram
cubic meters/m
cubic meters/m
cubic meters
liters
cubic centimet
degree Centigr
meters
liters
liters/second
killowatts
centimeters
atmospheres
kilograms
cubic meters/di
kilometer
atmospheres
(absolute)
square meters
square centime
metric tons
(1000 kilogra
meters
* Actual conversion, not a multiplier
190
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UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
OFFICIAL. BUSINESS ,„„„
PENALTY FOR PRIVATE USE $300 "'* """""""
AN EQUAL OPPORTUNITY EMPLOYER
Mr. Frank Corrado
Regional Public Affairs
Environmental Protection
One North Wacker Drive
Chicago, Illinois 60606
17
EPA FORM 1320-3 (REV. 6-72)
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