CONSTRUCTION GRANTS PROGRAM VOLUME III
INFORMATION
EPA-430/9-76-017c
appendix 8
FEDERAL GUIDELINES
STATE AND LOCAL
PRETREATMENT PROGRAMS
^ PRO^°
JANUARY 1977
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF WATER PROGRAM OPERATIONS
MUNICIPAL CONSTRUCTION DIVISION
WASHINGTON, D.C. 20460
-------
CONSTRUCTION GRANTS PROGRAM
INFORMATION
EPA-430/9-76-017c
VOLUME III
appendix 8
FEDERAL GUIDELINES
STATE AND LOCAL
PRETREATMENT PROGRAMS
JANUARY 1977
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF WATER PROGRAM OPERATIONS
MUNICIPAL CONSTRUCTION DIVISION
WASHINGTON, D.C. 20460
MCD43
-------
U.S. ENVIRONMENTAL PROTECTION AGENCY
FOREWORD
In response to the Federal Water Pollution Control Act Amendments
of 1972 (P.L. 92-500), this country has undertaken an unprecedented
program of cleaning up our Nation's waters. There will be a substantial
investment by Federal, State, and local governments as well as by private
industry in treatment works to achieve the goals of the Act. It is
important that this investment in publicly owned treatment works (PGTW's)
be protected from damage and from interference with proper operation,
and that receiving waters be protected from pollutants which may pass
through the POTW.
These guidelines were developed by the Environmental Protection
Agency in accordance with Section 304(f) of the Act for the purpose of
assisting States and municipalities in carrying out programs under
Section 402 including NPDES permit requirements. It is important to
note the clear requirements in the Act that there be both national
pretreatment standards, Federally enforceable, and pretreatment guide-
lines to assist States and municipalities in developing local pretreat-
ment requirements. The Environmental Protection Agency encourages the
establishment of local pretreatment requirements, tailored to local
conditions.
The guidelines are a revision of the previous guidelines, "Pre-
treatment o"f Pollutants Introduced Into Publicly Owned Treatment Works."
Contained in this revision is additional technical information on
pollutants which may interfere with or pass through publicly owned
treatment works. Also, guidance is presented to assist State and local
governments in developing their own pretreatment programs to comply with
NPDES permit conditions. The guidelines are the result of extensive
reviews and numerous field trips and discussions with EPA Regional
Offices, industry, city, regional, State and interstate agencies. We
are extremely grateful for the cooperation of those who assisted in the
preparation of the guidelines.
/s/ John Quarles
DECU2''J/b The Administrator
-------
TABLE OF CONTENTS(Continued)
VOLUME III
APPENDIX 8
Title Section
Introduction i
Code of Federal
Regulations (CFR
Industry Description Number)
Dairy Products 405 1
Grain Mills 406 2
Canned and Preserved Fruits
and Vegetables 407 3
Canned and Preserved Seafood 408 4
Sugar 409 5
Textiles 410 6
Cement 411 7
Feed Lots 412 8
Metal Finishing and
Electroplating 413 9
Organic Chemicals 414 10
Inorganic Chemicals 415 11
Plastics and Synthetic
Materials 416 12
Soap and Detergents 417 13
Fertilzer 418 14
Petroleum 419 15
Iron and Steel 420 16
Non Ferrous Metals 421 17
Phosphates 422 18
Steam Electric Power Plants 423 19
Ferro Alloys 424 20
-------
TABLE OF CONTENTS(Continued)
VOLUME III
APPENDIX 8
Leather 425 21
Glass 426 22
Asbestos 427 23
Rubber 428 24
Timber 429 25
Pulp, Paper and Paperboard 430 26
Builders Paper and Roofing Felt 431 27
Meat Products 432 28
Water Supply 437 29
Misc. Foods and Beverages 438 30
Misc. Chemicals 439 31
Auto and Other Laundries 444 32
Paint and Ink Formulation 446&447 33
Steam Supply and Noncontact
Cooling 449 34
Index
List of References
-------
INTRODUCTION
Purpose and Scope
The purpose of this volume is to provide data concerning
the major industries that may be contributing wastewater to
publicly owned sewer systems and treatment works. Included
are descriptions of thirty-four major industrial categories
which were partially established by the Federal Water Pollution
Control Act Amendments of 1972 (PL 92-500) and further developed
by the Effluent Guidelines Division of the Environmental Pro-
tection Agency.
The summary for each industrial category includes the
following information:
1. A general industry description of the products, raw
materials, waste characteristics, and Standard Industrial
Classification code numbers applicable to each industry.
2. The categorization and subcategorization developed
for the industry by the EPA in the effluent guidelines
program.
3. Process descriptions, based upon the subcategorization
established for the industry, with the major sources of waste-
water delineated for each process.
4. Waste characterization, including tables of concentra-
tion and production based data for the pollutants associated
with each industry.
5. Control and treatment technology including the in-plant
controls and end-of-pipe treatment utilized and available in
each industrial category.
The information presented herein was summarized from the
Development Documents prepared by the Effluent Guidelines
Division of the EPA. A list of these reference documents is
attached at the end of this volume.
The waste characterization tables provide broad ranges
of values which represent data from a cross-section of each
industry throughout the country- As a result, a particular
plant of interest may not be adequately characterized by the
values shown. The purpose of the tables is to furnish general
background information on the waste chracteristics of most
plants in the industry. For precise data, sampling of plant
effluent should be employed.
-------
In many cases, industrial plants utilize processes or
manufacture products encompassing more than one industrial
category or subcategory. In those instances, weighted averages
of the data should be used to represent the plant effluent.
Sampling at strategic points can be most useful in establish-
ing the effluent quality from multi-product or multi-process
plants.
Table i-1 summarizes the significant pollutant parameters
present in the effluent from each of the 34 major industrial
categories. In some cases, a particular parameter may only
be significant for one subcategory of the industry. To deter-
mine the applicable subcategory, reference should be made to
the summary for the specific industry in question. For further
information on a particular industry, the Development Document
for that industry should be consulted.
Pretreatment
The information contained in the individual industrial
summaries can be utilized to identify conditions requiring
careful evaluation when establishing pretreatment requirements
for a specific industry or when designing joint treatment
facilities. The wastewater characterization data is also a guide
for developing a wastewater testing program for a particular
industry. The control and treatment technologies identified
for each industry indicate in-plant control techniques and end-
of-pipe treatment processes available for use by industrial
dischargers.
Pretreatment of industrial wastes before discharge into a
POTW system is usually a case-by-case problem. In general, it
is usually required by the EPA, States or municipalities to
prevent the discharge of pollutants which may interfere with or
pass through municipal treatment plants, as described in
Volume 1. However, pretreatment decisions are frequently dic-
tated by the specific circumstances of each individual situation.
An industrial facility discharging directly to navigable waters
may decide to join a POTW system and pretreat after a technical
and economic analysis because it is the most cost-effective
alternative. Similarly, industries in the system may opt for
pretreatment where a small investment in pretreatment facilities
would result in a significant reduction in the pollutant loading
and a corresponding large reduction in surcharge or user
charge fees.
In all cases, in-plant control measures which might reduce
or eliminate the need for pretreatment facilities should first
be examined before embarking on a pretreatment program. In
many circumstances, a thorough examination of plant operational
practices, recycle alternatives, and other water conservation
or reuse possibilities can significantly reduce pollutant loads.
i-2
-------
TABLE 1-1
SUMMARY OF SHailFICANT POLLUTANT
PARAMETERS FOR MAJOR INDUSTRIES
Industry
Nitrate
Mercury Nitrogen Phenol Boron Seleniui
Dairy
Grain Mills
Canned and Preserved Fruits
and Vegetables
Canned and Preserved Seafood
bugar
Textile
Cement
Feedlots
Metal Finishing & Electroplating
urganic unemicais
Inorganic Chemicals
Plastics and Synthetics
Soap and Detergents
Fertilizer
Petroleum
Iron and Steel
Nonf errous Metals
Phosphates
Steam Electric Power
Ferroalloys
Leather Tanning & Finishing
Glass
Asbestos
Rubber
Timber
Pulp and Paper
Builders Paper
Meat
Paint and Tnlc
Auto and Other Laundries
Water Supply
Steam Supply
Misc. Foods and Beverages
Misc. Chemicals
X
X
X
X
X
X
X
X
X
X X X X
X
X
X
X
X
X
X
X
X
X
X
A
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X XX X X
X
X
A
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
A
X
X
X
XXX X
X
X
X
X
X
X
X
X
X
A
X
X X
X
X
X
X
X
X
X
X
X X
X
X
X
X
X
X
X
X
X
X
X X
X X
X
X
X X
X
X
X
X
X
X
X
X
X
X X
X
XX X
X
X X
X
X X
X X
X
X
X £
X
X
X
X
X X
X
X
XXX
X X
X X
X
X
X
X
X X
X
X
X
X
X
X
X X X X XX
X
X
X
XXX
XX XX
X X X X X X
XXX
XXX X
X X X
X
X
X X
X
X X X X X . X
X X X X XX
XXX X
XX XXX
-------
Accordingly, contained in each industrial summary is a dis-
cussion pertaining to available in-plant control technology
for the industry in question.
Pretreatment considerations may differ depending on
whether the pollutants to be controlled are susceptible to
treatment in a POTW. For compatible pollutants, pretreat-
ment would generally be employed because it is the most cost-
effective alternative, or because the POTW does not have
available design capacity to treat the wastes. Even in cases
where the municipality has available design capacity to accept
an industrial discharger without pretreatment, the industry
should still perform some sort of break-even analysis to deter-
mine if pretreatment is cost-effective. An example of this
type of analysis for the meat packing industry is contained in
Reference A-33. In cases where design capacity is not available,
the municipality may elect to assign waste load allocations to
each industrial discharger, thus fixing the required pretreat-
ment. Waste load allocation will in these cases be necessary
to meet the municipality's NPDES permit requirements.
Pretreatment for compatible pollutants can take a variety
of forms, including:
1. Coarse solids separation
2. Grit removal
3. Equalization
4. Neutralization
5. Dissolved air flotation
6. Sedimentation
7. Biological treatment
a. Activated sludge systems
b. Trickling filter systems
8. Physical-Chemical treatment
a. Chemical coagulation
b. Filtration
c. Activated carbon adsorption
Most pretreatment systems should include some form of coarse
solids separation, grit removal, and equalization. Equali-
zation may be required for either flow, pollutant load or both.
It is particularly important in the prevention of excessive
discharge and the imposition of shock loads on POTW systems.
Similarly, neutralization is a significant unit process in
pretreatment operations, to avoid possible process upset or
damage to POTW facilities by highly acidic or alkaline
wastes.
Dissolved air flotation and sedimentation are utilized
to remove suspended solids and floatable material such as
i-4
-------
oil and grease. Dissolved air flotation is particularly
useful in industries where oil and grease presents problems
in the discharge of wastewater to municipal systems.
Biological treatment is used in pretreatment operations to
reduce BOD loading prior to discharge to a municipal sewer.
The desired reduction is highly variable, and depends upon
economic considerations and available capacity in the
treatment facility- In many instances, a BOD reduction to
200-250 mg/1 is sought in pretreatment facilities to produce
an effluent which simulates domestic sewage. Frequently,
high rate activated sludge systems or roughing filters are
utilized in pretreatment systems to effect the desired BOD
reduction in the most cost-effective manner. Physical-
chemical treatment may be employed for suspended solids and
BOD removal where technical and economic factors favor this
alternative over conventional primary and biological treat-
ment processes.
Pretreatment for incompatible pollutants can also take
a variety of forms, including:
1. Coarse solids separation
2. Grit removal
3. Equalization
4. Neutralization
5. Dissolved air flotation
6. Sedimentation
7. Filtration
8. Chemical precipitation and coagulation
9. Activated carbon adsorption
10. Chemical conversion
The degree of pretreatment required for incompatible
pollutants is primarily determined by the level of discharge
into the municipal system required to prevent interference
or pass through, as outlined in Section E of Volume I. The
treatment of incompatible pollutants is frequently concerned
with the removal of inorganic suspended and dissolved solids
as opposed to the organic nature of compatible pollutants.
Consequently, the unit processes concerned with suspended
solids removal such as sedimentation and dissolved air
flotation involve the same considerations as with compatible
pollutants. Similarly, equalization and neutralization are
equally important in treating incompatible pollutants to
prevent shock loading and possible process upset or damage
to POTW facilities.
The distinguishing element in treating incompatible
pollutants is the removal of inorganic dissolved solids,
particularly metals. The most common processes employed are
chemical precipitation and coagulation and chemical conversion,
i-5
-------
In precipitation and coagulation, the dissolved pollutant
reacts with the chemical agent used to form an insoluble
precipitate. The precipitate is allowed to settle and is
removed as a sludge. In chemical conversion, the pollutant
in question is converted to another less harmful form or to
another substance. Typical of this type of treatment is the
reduction of hexavalent chromium to the trivalent form and
the destruction of cyanide. Activated carbon adsorption
may be used to remove dissolved organic pollutants which are
not susceptible to treatment in POTW's.
In summary, pretreatment must be evaluated on a case-by-
case basis within the context of cost-effectiveness and
applicable technical factors. Pretreatment considerations
depend primarily upon whether the wastewater in question is
compatible or incompatible with POTW systems. In either
case, a variety of unit processes are available to a par-
ticular industrial facility for pretreatment of wastewater
prior to discharge to a municipal sewer.
i-6
-------
DAIRY PRODUCTS
1- General Industry Description
The dairy processing industry manufactures various food products
utilizing milk, as a base. in addition, a limited number of
non-milk products such as fruit juices are processed in some
plants.
There are about 20 different types of products manufactured by
the industry. A substantial number of plants in the industry
engage in multi-product manufacturing, and product mix varies
broadly among such plants.
The Dairy Product Processing Industry includes Standard Indus-
trial Classifications (SIC) 2021, 2022, 2023, 2024, 2026 and
5043.
2. Industrial Categorization
Subcategory Designation
Receiving Stations A
Fluid Products B
Cultured Products C
Butter D
Cottage Cheese and Cultured Cream Cheese E
Natural Cheese and Processed Cheese F
Ice Cream Mix G
Ice Cream, Novelties, and other frozen desserts H
Condensed Milk I
Dry Milk J
Condensed Whey K
Dry Whey L
3. Process Description
Figure 8-1-1 is a flow diagram which shows a process representative
of the industry. The industry includes the following operations:
the receiving and storage of raw materials, processing of raw
materials into finished products, packaging and storing of
finished product, and a group of ancillary operations (e.g.,
heat transfer and cleaning) only indirectly involved in pro-
cessing of materials.
Facilities for receiving and storing raw materials consist of
a receiving area, transfer equipment, and large refrigerated
tanks for storage. Wastes arise from leaks, spills and equipment
wash outs. Under normal operations and with good housekeeping,
receiving and storage of raw materials are not a major source
of waste load.
8-1-1
-------
00
H
ro
1. Receiving
I-*-
2. Storage
3. Separation
4. Milk
Pasteurization
7. Culturing
I
8. Cooling
Packaging
Legend:
CS = Cleaning and Sanitizing Solution
WW = Wash Water (cold or hot)
CW - Cooling Water
ST « Steam
EF - Effluent to rtra
-------
The initial operations of clarification, separation and
pasteurization are common to most plants and products.
Clarification (removal of suspended matter) and separation
(removal of cream) generally are accomplished by using large
centrifuges of special design. In some older installations
clarification and separation are carried out in separate units
that must be disassembled for cleaning, sanitizing, and sludge
removal. In most plants clarification and separation are
accomplished by a single unit that automatically discharges
the sludge and can be cleaned and sanitized without disassembly
(cleaned in place, or CIP).
Following clarification and separation, those materials to be
subjected to further processing within the plant are pasteu-
rized. Pasteurization is accomplished in a few older plants
by heating the material for a fairly long period of time in a
vat (vat pasteurization). In most plants pasteurization is
accomplished by passing the material through a unit where it
is first rapidly heated and then rapidly cooled by contact
with heated and cooled plates or tubes (high temperature short
time or HTST pasteurization).
After the initial operations, the processes and equipment
employed become dependent on the product to be manufactured.
The processes employed for the manufacture of various products
include churning, homogenizing, culturing, condensing, and drying
The finished products are then packaged, cased and sent to
storage for subsequent shipment. The flow diagram shown in figure
8-1-1 is representative of many processes in this industry.
The product manufacture and packaging areas of a plant are the
major sources of wastes. These wastes result from spills and
leaks, wasting of by-products (e.g., whey from cheese making),
purging of lines during product change, product washing, and
equipment washups. Wastes from storage and shipping result
from the rupture of containers due to mishandling and should be
minimal.
4. Wastewater Characterization
Tables 8-1-1 and 8-1-2 show typical waste characteristics for
the dairy industry. A significant characteristic of the waste
streams of all dairy plants is the marked fluctuations in flow,
strength, temperature, etc. due to daily and seasonal variations.
Relatively clean water from condensers, refrigeration compressors,
milk coolers and air conditioning systems may be a substantial
portion of the total wastewater from a dairy plant. The major
sources of wastewaters from the dairy industry are:
1. Wash and rinse water from washups.
2. Unrecovered by-products.
3. Entrainment from evaporators.
4. Sewering of spoiled or damaged products.
8-1-3
-------
TABLE 8-1-1
DAIRY PRODUCTS
RAW WASTEWATER CHARACTERISTICS
Parameter Concentration Range
Flow Intermittent
BOD (mg/1) 4?000^60°§°1
TSS (mg/1) 400 - 2,000
TDS (mg/1)
COD (mg/1) 400 - 1500
pH 4-11
7.82
Phosphorus (mg/1) (as PO.) 9 - 210
4 48^
Ammonia Nitrogen (mg/1) 1 ~ 13
5.52
Total Nitrogen (mg/1) 1-2115
Chloride (mg/1) 45 -2000*
4832
Color High
Coliform Present
* See Appendix 5 for parameters which may be inhibitory to
biological systems
Narrower range encompassing the majority of plants
2
Mean for plants reporting
8-1-4
-------
TABLE 8-1-2
DAIRY PRODUCTS
RAW WASTEWATER CHARACTERISTICS BASED UPON
oo
I
ui
Parameter
Receiving
Stations
A
Flow Range ,
( gal/1000 llj 38/224
Flow Type
BOD(kg/kkg) 2
TSS (kgAkg)
B
.02/1.13
Fluid Cultured Cottage Natural Ice Creai
Products Products Butter Cheese Cheese Mix
B C D E F G
13/1000 - 150/800 100/1500 25/700
B B B B B
.14/17 - .2/2.0 1.3/42 .24/4.0
.13/3.36 - .1/0.27
B
.65
1 gallons/1000 Ib. milk equivalent (lower limit/upper limit)
2 kg/1000 kg of milk equivalent (lower limit/upper limit)
B Batch Process
-------
5. Control and Treatment Technology
In-Plant Control - Wastewater discharges can be reduced by:
a. Improved management control including measures to
minimize product losses, maintain equipment, develop alternative
uses for wasted products, and carefully supervise the operation.
b. Engineering improvements to plant, equipment, processes,
and ancillary systems can improve production efficiency ana
reduce waste loads.
Treatment Technology - The standard practice for reducing BOD
in this industry has been biological treatment, including
activated sludge, aerated lagoons, trickling filters and stab-
ilization ponds.
In addition, land application of wastewater can be practiced by
small dairy operations in rural locations. For the treatment
systems listed above, equalization is frequently required to
prevent shock loads to the system.
Treatment of wastes from the production of whey is more diffi-
cult than the other products and can cause upsets in the treatment
system. However, the equalization of pollutant loading can reduce
the impact of these wastes on biological treatment processes.
Whey treatment methods include:
1. Direct return to farmers supplying the
milk as feed.
2. Spray irrigation
3. Concentrating and drying
In general, dairy wastes are amenable to biological, as well as
chemical treatment if equalization and neutralization are provided
as pretreatment. However, care should be exercised in regard
to the discharge of whey POTW's. Whey generally has a relatively
high BOD5 value, and is normally nitrogen deficient. Conse-
quently, nutrient supplements such as digester supernatent can
be helpful in treating the waste in a biological system.
8-1-6
-------
GRAIN MILLS
1. General Industry Description
The grain mill industry converts harvested grain and/or grain
processing products into food and food intermediary products
for human and animal consumption. Starch for consumption as
well as for industrial use is also produced. The raw materials
include grains such as corn, wheat, rice; and meals such as
soybean and bonemeal.
This industrial category includes Standard Industrial Classifications
(SIC) 2041, 2043, 2044, 2046 and 2048. This report includes wet
milling of corn, but sorghum grain (milo) is excluded. Starch
from corn and wheat are included - other vegetable sources are
excluded (potato ). Establishments engaged in manufacturing
prepared dry foods, feed ingredients and adjuncts for animal
feed are included. Canned and frozen food preparations are
excluded.
2. Industrial Categorization
Subcategory Designation
Corn Wet Milling A
Corn Dry Milling B
Wheat Milling C
Bulgur Milling D
Rice Milling E
Parboiled Rice F
Animal Feed Manufacturing G
Hot Cereal Manufacturing H
Ready-to-Eat Cereal Manufacturing I
Wheat Starch and Gluten Manufacturing J
3. Process Description
Grain Mills - Figure 8-2-1 is a flow diagram for the grain
industry which shows the processes described below.
8-2-1
-------
DO
1
NJ
1
GKAI3 FHOCESSmS J
\
FACT CK:-£AI\ KTj
f-.>~ -TjCXvl .;. >
r
MffiAT
RICE
co?:;, p,A?,Lrnr, MILO, GHITS,
FLOW.
S I a
O I)
S g E
Wet Milling
A
Dry Milling
B
1 ».
Dry Milling
C
Bulgur Milling
D
i ^.
Rice Milling
E
|__^^
Pax-boilad Rice
F
|
^ (Vrn ill
Hulls, etc. ' *- Syrup
i
Bran, Germ, etc.
Bran, Germ, etc.
I
Bran
i
Hulls, Bran, etc.
Bran, etc.
Animal Food
Manufacturing
G
Hot Cereal
Manufacturing
H
Heady to Eat
Cereal Manufacturing
I
Wheat Starch &
Gluten Manufacturing
Figure 8-2-1
GRAIN MILLS
PRODUCT MAHUFACTURIBG FLOW DIAGRAM
-------
Corn Wet Milling (A) - This operation produces starch, oil,
syrup, and dextrose, as well as animal feed by-products from whole
kernel corn. The corn wet milling operation can be considered
to consist of three basic processes:
1. Milling
2. Starch Production
3. Syrup Manufacturing
GERM-
_>CORH OIL
CORN->
HULLS
GLUTEN"
MODIFIED
STARCH
SYRUP &
DEXTROSE
ANIMAL
FEED
CORN WET MILLING (A)
Figure 8-2-2
The initial wet milling sequence separates the basic components
of the corn kernel into starch, germ, gluten and hulls, from
which the end products are derived. The starch slurry may either
be dried, modified and then dried or converted into corn syrup
or dextrose. In processing the starch slurry, the fractions are
apportioned between starch finishing and sweeteners according to
market demand. Modification of the starch imparts characteris-
tics to it which may be required for its end use - either for
paper or food products, textile manufacturing, building mater-
ials., laundries, etc.
Corn wet milling, shown in Figure 8-2-3 begins with the storage
and dry cleaning of shelled corn. The corn is steeped in hot
sulfurous acid solution in order to soften the kernel for mill-
ing. Steeping helps break down the protein holding the starch
8-2-3
-------
SHELLED CORN
^
J STEEPWATER
w
STEEPWATER
STORAGE AND
CLEAING
STEEP TANKS
DEGERMINATORS
EVAPORATORS
r-H
STEEPWATER
CONCENTRATES
^
r
1 HULL
A GLUTEN
r *
FEED D R E R S
FEiDS
^
I
1
1
_L -
GERM SEPARATORS
GRINDING MILLS
WASHING SCREENS
C E N T R F U G AL
SEPARATORS
STARCH
WASHING IIITIBS
GERM I
CRUDE
FILTERS
1
CENTRIFUGAL
SEPARATORS
1
DEODORIZERS
1
FILTERS
| W»SHINt I D«»INC
' OF HUMS T
"^
OIL EXTRACTORS
^
1 CORN Oil .
1 ME Al
I
REFINED OIL
*^p-
SYRUP S SUGAR
CON VIBIOBS
1 STARCH ! '
r-
j R E F N 1 N G
, 1 _
STARCH DRIERS 1 CORN SYRUP
I +
DRY STARCHES ° Jo^TlVs "
1
D E X T R 1 N S
DRUM Of SPRAY
DRIERS
SUGAR
(B YSUHIillS
1 1
CORN SYRUP SOUDS
CENTRIFUGALS
1
DEXTROSE
FIGURE 8-2-3
THE CORN WET MILLING PROCESS (A)
8-2-4
-------
particles, and removes certain soluble constituents. Part of
this steepwater is drained, evaporated, and protein is recovered
for addition to animal feeds or for use as a nutrient in fermen-
tation processes. The steeped corn then passes through deger-
minating mills which tear the kernel apart to free the germ and
some starch and gluten. The germ is then separated from the
mixture, is washed, dried, and the oil is extracted to produce
corn oil. The spent germ is then sold as corn oil meal.
Wastewaters from corn wet mills contain large amounts of BOD
and suspended solids.
The product slurry passes through a series of washing, grind-
ing and screening operations to separate the starch and gluten
from the fibrous material. The hulls are discharged to the feed
house for use in animal feeds.
At this point, the main product stream contains starch, gluten,
and soluble organic materials. The lower density gluten is
then separated from the starch by centrifugation and is proc-
essed for animal feed.
The starch slurry can now be directed into one of three basic
finishing operations:
1. Ordinary Dry Starch
2 . Modified Starches
3 . Corn Syrup and Sugar
Starch may be dried and packaged or modified for special uses.
Sjyrups and Sugar-Syrups and sugars are formed by hydrolyzing the
s~tarch; partial hydrolysis producing corn syrup, and complete
hydrolysis resulting in corn sugar. This step can be accom-
plished by using mineral acids or enzymes, or a combination of
both. The product is then refined and concentrated before stor-
age and shipping. The production of dextrose is quite similar
to that of corn syrup.
Corn Dry Milling (B) - Corn is dry cleaned, and then
washed. Wastewaters from washing operations normally go through
mechanical solids recovery and then are discharged. The next
operation is tempering, or adding water to the corn to raise the
moisture content in order to make it more suitable for subsequent
milling. Only enough water is added in this operation to reach
the desired moisture content and no wastewater is generated.
The corn is passed through a series of roller mills, sifters, and
separators, where germ and hulls are separated and the fine prod-
8-2-5
-------
uct stream goes to reduction mills to produce corn flour.
Other than infrequent equipment washing, the only process
wastewater in this process is that originating from the wash-
ing of corn. It is characterized by high BOD and suspended
solids. A process flow diagram is shown in Figure 8-2 4.
Wheat Milling (C) - The .wheat milling process, presented in
Figure 8-2-4 starts with dry, matured, partly cleaned wheat seed.
The normal milling of wheat into flour uses water only in tern
pering (described in (B) ) a consumptive process, and in cool-
ing. A few flour mills do wash the wheat, but the vast major-
ity use dry cleaning techniques. The wheat is then ground in
tq flour and its by-products which are used as animal feed addi-
tiVes.
Bulgur Milling (D) - Bulgur is wheat that is parboiled, dried,
and partially debranned for use in either cracked or whole grain
form. After the washing and the tempering operation (described
in (B) ), water and live steam are added to the grain and it is
cooked, then dried. The dried wheat is then polished, ground
and sifted. The bulgur is packaged, and the by-products are
used as animal feed additives. Wastewaters are high in BOD, COD,
and suspended solids. A process flow diagram is shown in Figure 8-^-4,
Rice Milling (E) - Rough rice is cleaned and mechanically proc-
essed to separate bran, shells, hulls from the brown rice, white
rice, and rice flour.The operation utilizes no process waters
and, hence, generates no wastewaters. A process flow diagram
is shown in Figure 8-2-5.
Parboiled Rice (F) - Rice that has been sorted and cleaned is
cooked under pressure, then dried. Modest amounts of wastewaters
high in BOD are generated. A process flow diagram is shown in
Figure 8-2-5.
Animal Feed Manufacturing (G) - The processing of various grains,
grain milling by-products, and other materials into prepared ani-
mal feed requires only small volumes of process water. Waste-
waters include boiler blowdown and cooling waters. No process
wastewaters are discharged.
Hot Cereal Manufacturing (H) - In general, only dry milling and
blending operations are involved in hot cereals manufacture.
Water is consumed in several processes, but no wastewaters result
from this operation.
8-2-6
-------
00
10
-J
WA
WASTEWA1
WAI
STE
STE
MIUFEEO^K
FER- .
ER4-
AM
AM ^
9"*N ^
WHEAT
4
RECEIVING
STORAGE i
DRY CLEANING
WATER
nTl
-| WASHING
WHEAT
*
-^ J,
WHEAT
WASHING
I 1
4
V
f WASTEWATER
SOAKING
|
PRESSURE
COOKING
1
DRYING
COOLING
1
POLISHER
1
GRINDING
1
BRAN
SIFTING
MILLFEEO ^
' ' ^ MEAL ft FtOUB
BRAN
BRAN »_,
SHORTS
GERM
inoiTIVES
ADDITIVES -. 1
ENRICHING
* BLENDING
4
BULGUR WHEAT
THE BULCUR PROCESS <3)
RECEIVING
STORAGE!
DRY CLEANING
WATER
, r STEAM
TEMPERING
I
BREAKER
I
SIFTER
1
PURIFIER *A!
1
REDUCING
ROLL
1
SIFTER
1
-* 1
MILLFEED ^ J
BLEACHING t
ENRICHING
1
FLOUR
THE WHEAT MILLING PROCESS ^C)
CORN
^
RECEIVING
DRV CLEANING
1
OEWATERING '
4r 1
I ^ 1 I
SOLIDS J
RECOVERY
-, 1 1 OEGERMING
I 1 ' I '
TEWATEft SOLIDS I
TO FEED '
DRYING 4
COOLING
1
HULLS MILLING* V CORN GRITS
HCERM I I
^ 1
OIL EXPELLING REDUCTION
1 EXTRACTING MILLING
4 1
CORN OIL CORN FLOUR
THE DRY CORN MILLING PROCESS (B)
FIGURI!^8^2-4
GRAIN MILLING
-------
ROUGH RICE
ROUGH RICE
^1
TO MILL
HULLS
BRAN &
RICE POLISH
BRAN
r VITAMIK
ADDIT
RECEIVING
STORAGE 4
DRY CLEANING
I
SHELLER
»
SEPARATOR
L
1
|
IS &
ON4-
TRUMBLE
W RICE POLISH
' TO MILLFEEO
SCREENINGS
*
HOT WATER ^
STEAM ^
SECOND HEADS
-, r-
SCREEN &
SEPARATOR
RICE FLOUR
MILLING
^
TO MIL
1 i
WHITE RICE RICE FLOUR
FIGURE 5
THE RICE MILLING PROCESS (E)
HULLS
RICE POLISH
r
LFEED
P
THE PARBC
RECEIVING
STORAGE
DRY CLEANING
|
STEEP
TANKS
|
COOKER
1
DRYER
COOLER
1
SHELLER
1
WHITENER
PEARLER
BRUSH
1
TRUMBLE
^ WASTE WATER
1
SCREEN &
SEPARATOR
*
ARBOILED RICE
FIGURE 6
(LED RICE PROCESS (F)
FIGURE 8-2-5
RICE MILLING
-------
Ready-To-Eat Cereal Manufacturing (I) - Ready-to-eat cereals
include flaked, crisped, shredded, puffed and extruded varie-
ties. A large portion of the total water consumption of a plant
is due to wet clean-up and washing operations, but several of
the processing steps also require water. Except for the cook-
ing operation in shredded cereal manufacture, the added moisture
remains with the product until it is released as a vapor in a
drying operation or it is consumed. Wastewaters from shredded
cereal manufacturing are higher in BOD, COD, dissolved and sus-
pended solids than the other ready-to-eat cereals. Water is
used for cooling equipment and in wet scrubbers for air pollu-
tion control. A process flow diagram for shredded cereal pro-
duction is shown in Figure 8-2-6.
Wheat Starch and Gluten Manufacturing (J) - Lower grades of
wheat flour are mixed with water into a dough, allowed to ma-
ture, and after repeated washings are separated into starch and
gluten. The gluten, high in protein, is dried and packed and
used as an ingredient in bakery produce. It can also be proc-
essed into monosodium glutamate (MSG), a flavor enhancer. The
starch-laden stream is thickened, dewatered, dried and packaged.
Wheat starch has widespread use in the food and textile indus-
tries and in adhesives. Moderate amounts of wastewaters are
generated which are high in BOD and suspended solids. A process
flow diagram is shown on Figure 8-2-7.
4. Wastewater Characterization
Wastewater generated in grain mills may be somewhat deficient in
nitrogen for biological waste treatment. Wet corn mills typically
generate large volumes of wastes containing significant quantities
of BOD and suspended solids. These concentrations in turn depend
to a large degree on the quantities of once-through contact cooling
waters utilized in the process. Wastewaters from ready-to-eat
cereal plants vary considerably in quantity and character.
Tables 8-2-1 and 8-2-2 contain raw wastewater data for the
various subcategories.
5. Control and Treatment Technology
In the Grain Processing category only Corn Wet Milling (A) has
had attention focused on control and treatment of its wastes.
This is due to the large quantities of wastewaters discharged
in contrast to the much smaller amounts generated by the other
types of grain milling (B, C, D, E, F). In many instances, the
treatment technologies developed for Corn Wet Milling (A) can
be applied to other subcategories.
Animal Feed (G) and Hot Cereal (H) generate no process waste-
waters. Most of the Ready-To-Eat Cereals (I) industry discharge
medium strength wastes to large municipal systems which are
capable of handling the industrial waste loads. Some plants
8-2-9
-------
WHEAT
WATER
WASTE
WATER
COOKING
I
TEMPERING
1
SHREDDING
TOASTING
SUGAR
COATING
I
VITAMIN
ADDITION
f
PACKAGING
PACKAGING
FIGURE 8-2-6
SHREDDED CEREAL PRODUCTION (I)
8-2-10
-------
WHEAT F1.OUR
4^
WATERS
-^
WATER i
WATER w
WATEfl^
WATER K
DOUGH
MAKING
|
DOUGH
WASHING
WATER
...... fe RHITP*1 fc fSIIITPM ^ Q1IITF?,!
^" WASHING DSWATERI?«1 ^^ DRYIN<3
N }4 1 J
SCREENING
|
FINE
SCREENING
4
THICKENING
CENTRIFUGE
| ^
> " « SSS!
GLUTEN
PACKING
^ WASTE WATER
WATER ^ ^
+* \ 4, \ I
CENTRIFUGE
1
A-STARCH
DEWATERINQ
|
A-STARCH
DRYING
A-STARCH
PACKING
* 9
>^h n CT^ D/^U ' ^^ A^CTA D/^JJ
- CENTRIFUGE r CONCENTRATION ^ DEWATERtNG
_J B-STARCH
DRYING
B-STARCH
PACKING
FIGURE 8-2-7
WHEAT STARCH AND GLUTEN MANUFACTURING (J)
8-2-11
-------
TABLE 8-2-1
RAW WASTEWATER CHARACTERISTICS
GRAIN PROCESSING INDUSTRY
Parameter , mg/1
Average Flow(MGD)
Flow Type
BOD5
TSS
co TDS
i
ij> COD
N> pH
Phosphorus
Nitrogen
Temperature (°C)
Corn Wet
Milling
A
25MM
B-C
225-7600*
81-2458
Present
473-4560*
5.9-7.9
Present
o-io 1
High
Corn Dry
Milling
B
130M
B
600-2748*
1038-3485
Present
1795-4901*
3.7-7.8
30-65*
0-10
Normal
Wheat
Milling
C
Nil
Nil
Nil
Nil
Nil
Nil
Nil
0-10
Nil
Bulgur Rice
Milling Milling
D E
10M-30M 0
B
238-521
294-414
Present
800
5.8
5.6
0-10
High
Parboiled Animal
Rice Feed
F G
70M-200M 0
B
1280-1305*
33-77
1687
2810-3271*
6-9
30-65*
7.0
High
Hot Ready to
Cereal Eat Cereal
H I
0 140M-8.4MM
B-C
420-2500*
80-1572
0-7619
804-6040*
4.1-8.6
Present
5-301
71-74*
Starch &
Gluten
J
120M
B-C
6200-14,633*
4176-14,824
Present
9300-25,040*
3.5-4.9
100
350-400
Normal
Note: *See Appendix 5 for parameters which may be inhibitory to
biological systems.
B - Batch Operation
C - Continuous Operation
M - 1000
MM - 1,000,000
May be nutrient deficient
-------
GRAIN PROCESSING
oo
I
ro
I
M
CJ
RAW WASTEWATER DATA
BASED UPON PRODUCTION
TABLE 8-2-2
A B CDE PGHIJ
Parameter Corn Wet Corn Dry Wheat Bulgur Rice Parboiled Animal Hot Ready Wheat,
Feed Cereal to Eat Starch &
Cereal Gluten
Suspended .5/9.8
Solids range
(kgAkg)
Milling Milling Milling
Neg. 38M/115M 0
Neg. - 0
Neg. - 0
7.4 1.14 Neg. .11 0
Neg.
Plow Range 3.1M/41.7M 480/900
(lAkg)1
Average Flow 18.3M
(lAkg)
BOD Range 2.1/12.5
(kgAkg2:
BOD Avg.
(kgAkg)
0
Suspended
Solids Avg.
(kgAkg)
3.8
1.62
COD Range 6.8/22.3
(kgAkg)
COD Avg.
(kgAkg)
14.8
Neg.
Neg.
Neg.
.10
Rice
1.4M/2.1M 0
1.8
.07
Note: 1 lAkg liters/1000 kg product produced- (lower limit/upper limit)
2 kgAkg kilograms/1000 kg product produced (lower limit/upper limit)
Neg. Negligible
Concentration Unknown
M - 1000
MM - 1.000,000
0 2.5M/9.6M 7.4M/12.4M
0 5.82M 9.95M
0 2.2/18.2 80/108
0 6.6 90.7
0 .6/2.7 52/110
1.4
75.7
0 5.7/42.4 116/260
15.7
198.6
-------
provide pretreatment facilities to reduce waste loadings prior
to municipal discharge. Both in-plant control measures and
effluent treatment systems are essential to wastewater reduction,
In-Plant Controls - All corn wet mills presently incorporate
many water recycling and reuse techniques. Through research,
new markets were found for materials that were once wasted,
such as steepwater. Efforts to improve product recovery and
simultaneously to reduce waste discharges, have led to inno-
vative process operations which utilize recycled water.
Several plants have converted barometric condensers to sur-
face condensers to reduce wastewater volumes. Other plants re-
circulate the barometric cooling water over cooling towers.
Improved operator control and expanded evaporator capacity can
reduce liquor boil-over and resultant heavy discharges. Gen-
eral operational and housekeeping procedures have a marked
effect on the amount of wastes discharged.
It is doubtful that any major reductions in waste load can be
achieved through in-plant controls or modifications at exist-
ing starch plants (J). Since product yield is economically
crucial to these producers, a high degree of product recovery
is practiced. New plants are being designed to further re-
duce wastewater discharges.
Treatment Processes - Several Wet Corn Mill (A) plants provide
treatment or pretreatment of the plant effluent. Treatment
and pretreatment processes range from settling and/or aeration
to complete activated sludge systems. Frequent upsets in this
industry cause shock loads which reduce treatment efficiency.
The other Grain Milling processes (B, C, D, E, F) qanerate
wastewaters that are amenable to conventional biological treat-
ment.
Process wastewater from wheat starch and gluten (J) manufac-
turing is readily biodegradable and treatable by conventional
biological treatment systems. Pilot plant studies on one
pretreatment facility yielded BOD reductions of up to 98%.
The system included aeration and settling, rotating biological
disc, and a polishing pond.
Wastewater treatment practices are shown on Table 8-2-3.
8-2-14
-------
Table 8-2-3
GRAIN INDUSTRY
Wastewatcr Treatment Practices
Percent Reduction
Treatment Method
Activated Sludge
BOD reduction
SS reduction
Sludge
Equalization + Act.
BOD reduction
SS reduction
Equalization + Act. Sludge
+ Stabilization Lagoon
BOD reduction
SS reduction
Equalization + Act. Sludge
+ Deep Bed Filtration
BOD reduction
SS reduction
Equalization + Act. Sludge
+ Deep Bed Filtration +
Activated Carbon Filtration
BOD reduction
SS reduction
Equalization + Act. Sludge +
Deep Bed Filt. + Act. Carbon
Filt., + Reverse Osmosis
BOD reduction
SS reduction
Primary Sedimentation
BOD reduction
SS reduction
Primary Sedimentation +
Activated Sludge
BOD reduction
SS reduction
Corn Wet
Milling
A
80
58
90
80
95
90
97.4
96.9
99.5
99.0
99.5
99.0
Corn Dry
Milling
B
Primary Sedimentation +
Act. Sludge + Stabilization
Lagoon
BOD reduction
SS reduction
Prim. Sedimentation + Act.
Sludge + Deep Bed nitration
BOD reduction
SS reduction
Prira. Sed.. + Act. Sludge +
Deep Bed Filt.. Activated
Carbon Filt.
BOD reduction
SS reduction
Act. Sludge + Deep Bod Filt.
BOD reduction
SS reduction
Act. Sludge. Dc-cp Bod Filt. +
Activated Carbon Fiit.
BOD reduction
SS reduction
Activated Sludge +
Stabilization Lagoon
BOD reduction
Bulgur
92.5
91.7
Parboil
Rice
92.8
Ready-To-Eat Starch & Gluten
I J
43
80
94.3
96.0
97.4
98.2
98.6
99.4
99.7
99.8
92
59
94
69
95-97.5
75-87
97.4-98.3
91.4-95.7
99.6
97.9
99.6
97.9
96.2
97.8
98.8
98.6
98.2
86.4
99.6
90.9
96.7
95.6-97.8
94.7-98.7
96.7-98.3
96.0-98.7
98.3-98.9
98-99
99.4-99.7
99.6-99.7
99.8-99.9
99.8-99.9
99.9
99.9
8-2-15
-------
CANNED AND PRESERVED FRUITS
AND VEGETABLES
1. General Industry Description
The processes of the canned and preserved fruits and vegetables
industry extend the shelf life of raw commodities through the
use of various preservation methods including canning, freezing,
dehydrating, and brining. Fruit and vegetable preservation
generally includes the following unit operations: cleaning
and sorting, peeling, sizing, stabilizing and processing.
Fruit and vegetable processing plants are major water users
and waste generators. Raw foods must be rendered clean and
wholesome and food processing plants must be sanitary at all
times.
For the most part these wastes have been shown to be biode-
gradable, although salt is not generally removed during the
treatment of olive storage and processing brines, cherry
brines, and sauerkraut brines.
This industry encompasses Standard Industrial Classifications
(SIC) 2032, 2033, 2034, 2035, 2037, and 2099.
2. Industrial Categorization
The apple, citrus and potato processing segment of the industry
has been subcategorized as follows:
Subcategory Designation
Apple Juice A
Apple Products B
Citrus Products C
Frozen Potato Products D
Dehydrated Potato Products E
The above subcategorization does not include caustic peeled and
dehydrated apple products, and pectin and Pharmaceuticals
derived from citrus products. The remaining part of the industry
has been tentatively subcategorized, but is still subject to
change. The tentative subcategorization is as follows:
1. Added ingredients
2. Apricots
3. Asparagus
4. Baby foods
5. Beets
6. Broccoli
7. Brussels sprouts
8. Caneberries, blueberries
9. Carrots
10. Cauliflower
11. Cherries, sweet and sour
8-3-1
-------
12. Cherries, brined
13. Corn
14. Corn chips
15. Cranberries
16. Dehydr.ated onions and garlic
17. Dehydrated vegetables
18. Dried fruits, prunes, figs
19. Dry beans, canned
20. Ethnic vegetables, Chinese and Mexican
21. Grape pressing
22. Grape juice
23. Jams, jellies and preserves
24. Lima beans
25. Mayonnaise and salad dressings
26. Mushrooms
27. Olives
28. Onions (canned)
29. Peaches
30. Pears
31. Peas
32. Pickles, fresh pack
33. Pickles, process pack
34. Pimentos
35. Pineapples
36. Plums
37. Potato chips
38. Prune juice
39. Pumpkin and squash
40. Raisins
41. Sauerkraut, cutting
42. Sauerkraut, canning
43. Snap beans (green and wax)
44. Soups
45. Spinach/leafy greens
46. Strawberries
47. Sweet potatoes
48. Tomatoes, peeled
49. Tomato products
50. Tomato - starch - cheese, canned specialities
51. White potatoes, whole
3. Process Description
In general, all subcategories have similar process operations
as follows:
Field to Plant - The crop is harvested, separated from "trash"
(stems,leaves), sorted, transported, and received at the plant.
No wastewaters are generated.
8-3-2
-------
Washing and Rinsing
Prior to processing the fruits and vegetables are washed and
rinsed by means of flumes, soak tanks, water sprays, flotation
chambers, or any combination of these methods. Great quantities
of water are used. Detergents and ultrasonic techniques are
also being tested for increased cleaning efficiency.
Sorting (Grading)
The commodity is sorted and graded by mechanical,optical,manual
or hydraulic means. Density graders employing brine of controlled
density are used to separate mature from over mature produce.
Weed seeds, chaff, and s-tones may be separated by density and in
froth separators.
Stemming, Snipping, Trimming
Stemming, snipping, and trimming are accomplished by a variety of
mechanical means. No wastewaters are generated.
In-Plant Transport
Various means have been adapted for conveying fruit or vegetable
products at unloading docks into and through the processing
plant. These include fluming, elevating, vibrating, screw
conveying, air propulsion, negative air conveying, hydraulic
flow, and jet or air blasting. Water, in one way or another,
has been extensively used in conveying products within plants
because it has been economical in such use and because it serves
not only as conveyance but also for washing and cooling.
It has been traditional to consider water an economical means to
transport fruits and vegetables within a plant and to assume
there was some sanitary significance to such use, not only for
the product, but also for the equipment. A significant disadvantage,
however, may be leaching of solubles from the product, such as
sugars and acids from cut fruit; and sugars and starch from cut
corn, beets, and carrots. Alternative systems to decrease such
losses from water have been investigated, such as osmotically
equivalent fluid systems.
Peeling
Many fruits and vegetables are peeled for processing. This
serves the multiple purpose of removing residual soil, pesticide
residues, and coarse, fuzzy, or tough peeling with unplesant
appearance, mouth feel, or digestive properties.
Peeling is accomplished mechanically by cutting or abrasion;
thermally by puffing and loosening the peel by application of
steam, hot water, hot oil flame, or blasts of heated air; or
chemically, principally using caustic soda (with optional sur-
factants) to S9ften the cortex so it may be removed by mechanical
scrubbers or high-pressure water sprays.
8-3-3
-------
Pitting, Coring, Slicing and Dicing
Pitting, coring, slicing and dicing are accomplished by a
variety of mechanical techniques depending upon commodity used
and end product desired. No wastewaters are generated.
Pureeing and Juicing
Widely varied techniques are used for pressing and separating
fluid from fruits and vegetables. Equipment includes reamers
and a wide variety of crusher-presses, either batch or continuous
in operation.
The oxygen and other gases (nitrogen, carbon dioxide) present
in freshly pressed or extracted fruit and vegetable juices
may be effectively removed by deaeration under vacuum. The
liquids to be deaerated are pumped into an evacuated chamber
either as a spray or as a thin film. Modern deaerators operate
at a vacuum of 29 inches or above. Deaeration properly carried
out not only improves color and flavor retention, but reduces
foaming during filling and also reduces separation of suspended
solids.
In the concentration of solutions by evaporation, the liquid to
be concentrated continuously flows across a heat exchange surface
which separates it from the heating medium. There are various
types of evaporators, including: open kettles, shell-and-tube
heat exchangers, flash evaporators, rising and falling film
evaporators, plate type evaporators, thin-film centrifugal
evaporators, vapor separators, nacuum evaporators and heat pump
evaporators.
The process involves heating the product to evaporation and
separating the vapors from the residual liquid.
Size Reduction
A wide range of size reduction equipment is required to produce
different types of particulated solids. Selection of a machine
which can most economically produce desired results is affected
by physical characteristics of the material and by the required
particle size and shape.
Blanching
Blanching (scalding or parboiling) of vegetables for canning,
freezing,or dehydration is done for one or more reasons: removal
of air from tissues; removal of solubles which may affect
clarity of brine or liquor; fixation of pigments; inactivation
of enzymes; protection of flavor; leaching of undesirable flavors
or components such as sugars; shrinking of tissues; raising of
temperature; and destruction of microorganisms.
8-3-4
-------
Blanching is accomplished by putting the products in contact
with water or steam. In almost all cases for preparation of
vegetables to be frozen, it is imperative that the blancher
processes be terminated quickly. Consequently, some type
of cooling treatment is used. Typically, if the product has
been water blanched, the vegetable is passed over a dewatering
screen and cooled either by cold water flumes or cold water
sprays. Product to be canned is usually not cooled after
blanching.
The pollution loads from blanching are a significant portion
of the total pollution load in the effluent stream during the
processing of certain vegetables.
Canning
The sanitary codes of most states require that cans be washed
before being filled. There are usually three steps in the
can cleaning operation. First, the cans travel a short dis-
tance in the inverted position; second, they are flushed with
a relatively large volume of water under high pressure; and
third, they travel another short distance in the inverted pos-
ition for the purpose of draining excess water. This is
usually accomplished mechanically.
The commodity is then filled ifato the can by hand, semiautomatic
machines, or fully automatic machines, depending on the product
involved. In some products, there is a mixture of product
and brine or syrup. In other cases, brine or syrup is added
hot or cold as top-off liquid. When the top-off is cold, it
is necessary to exhaust the headspace gases to achieve a vacuum
and maintain product quality.
Exhausting in order to create a vacuum, is usually accomplished
by one of the three methods:
1. Thermal exhaust or hot filling. The contents of the con-
tainer are heated to a temperature of 160° to 180°F, prior
to closing the container. Contraction of the contents of
the container after sealing produces a vacuum.
2. Mechanical. A portion of the air in the container head-
space is pumped out by a gas pump.
3. Steam displacement. Steam is injected into the headspace
to replace the air, and sealed. A vacuum is produced
when the steam condenses.
8-3-5
-------
Drying or Dehydration
Continuous belt dryers are the most commonly used method
for dehydration. They are usually long and^multi-staged with
baffled chambers which blow heated and sometimes desiccated
air from over and under the bed-depth of the raw slices.
Residence time in this type of dryer is usually ten to twenty
hours, resulting in a product that has a finished moisture
content of no greater than 4.25 percent of onions or 6.0 per
cent for garlic.
Post-Drying Operations
After dehydration the dried slices are usually screened, milled,
aspirated, separated, and ground in various mechanical combin-
ations to achieve the final desired piece size.
Mixing and Cooking
Certain commodities utilize additional ingredients in the manu-
facture of the finished products. For example, many frozen
vegetables are prepared with butter, cheese, cream sauce, sugar,
starch and tomato sauce added. Equipment washouts and spills
add an incremental waste load to the total plant waste production.
Freezing
Freezing is accomplished in a tunnel frezzer. The frozen
commodity is then inspected, sorted and sized prior to packing.
The only waste loads generated from this operation are from
the clean-up operations and from cooling water.
Clean-Up
Clean-up operations vary widely from plant to plant and from
product to product. Normally the plant and equipment is cleaned
at the end of the shift, usually by washing down the equipment
and floors with water. In some plants it is desirable to main-
tain a continuous cleaning policy so that end-of-shift clean-up
is minimized.
Clean-up begins with a dry collection of wastes followed by a
washdown. The washdown may be done with either water alone or
with water mixed with detergent. Water is applied through
either high-volume, low-pressure hoses or low-volume, high-
pressure hoses.
In some operations, such as the mayonnaise processing operation,
clean water is used to flush out the entire system at the end
of the shift to remove any residues which might harbor bacterio-
logical growth.
The water used in clean-up operations generally flows through
drains directly into the wastewater system.
8-3-6
-------
4. Wastewater Characterization
Wide ranges of wastewater volume and organic strength are
generated by this industry depending upon the particular
commodity being processed, the particular operation employed,and
daily and seasonal variations. Treatment facilities must be
designed to handle large volumes intermittently. Citrus wastes
are highly putrescible and contain pectic substances which inter-
fere with the settling of suspended solids.
Table 8-3-1 gives the raw waste characteristics for this industry.
The table has been grouped by the following formula:
Group I - Commodities with BOD less than 500 mg/1
Group II - Commodities with BOD between 500-1000 mg/1
Group I'll - Commodities with BOD between 1000-2000 mg/1
Group IV - Commodities with BOD between 2000-3000 mg/1
Group V - Commodities with BOD between 3000-5000 mg/1
Group VI - Commodities with BOD greater than 5000 mg/1
5. Control and Treatment Technology
In-Plant Control - The use of field washing in place of certain
washing procedures in the processing plant can reduce the waste
loads produced at the processing plant. Wastewaters produced
in the field can easily be disposed of on land, eliminating a
wastewater source. r The use of mechanical peel removal in place
of water can reduce the waste load.
The use of dry methods of in-plant transport in place of water
transport methods has been examined by this industry. Although
dry transport methods greatly reduce the waste loads, they are
much more costly. The use of fluidized bed and microwave blanch-
ing techniques have been examined and have been found to reduce
waste loads; however the costs have been found to be too high
to be viable at the present time.
In*plant water reuse has been practiced in this industry. An
example of this is the use of spent cooling water to wash products
following blanching, and then in turn using this water to wash
the incoming raw product. In some cases water to be reused
will require treatment such as chlorination to meet product
quality requirements.
Treatment Technology - As can be seen from Table 8-3-1 the major
pollutant parameters generated by this industry are BOD and TSS.
Suspended solids can be removed by screening, sedimentation or
flocculation with clarification. Since caustic is used in some
operations, pH adjustment may be required in some cases.
8-3-7
-------
TABLE 8-3-1
CANNED AND PRESERVED FRUITS AND VEGETABLES INDUSTRY
RAW WASTEWAIEH CHARACTERISTICS
Group I
Group II
Group III
Group IV
Group V
Group VI
BODc - Less Than
500 rag/I
Subcategory
C
3
6
7
f 8
UJ
1
00 10
16
17
27
43
44
45
Citrus
Asparagus
Broccoli
Brussels
Sprouts
Caneberries
Blueberries
Cauliflower
Dehydrated
Onions and
Garlic
Dehydrated
Vegetables
Olives '-*-'
Snap Beans
(Green & Wax)
Soups
Spinach/
Leafy Greens
TSS
mK/1
130
43-114
100-455
29-1680
52-184
18-113
168-778
304
400
76-348
365
19-419
BODc*
500 - lOOO mg/1
Subcategory
A Apple Juice
1 Added Ingred.
4 Baby Foods
15 Cranberries
2O Ethnic Veget.
Chin. & Hex.
24 T.inin Beans
38 Prune Juice
41 Sauerkraut
Cutting
46 Strawberries
48 Tomatoes
Peeled
49 Tomato
Products
TSS
mg/1
104
101-533
35-84
140-246
82-584
153-165
143
96-210
280-1280
512-1180
BOD5*
10OO - 2000 mg/1
Subcategory
B
D
E
2
19
26
28
29
33
34
36
42
50
Apple Prod.
TSS
mg/1
150
Frozen Potatoes 1716
Dehydrated
Potatoes
Apricots
Dry Beans,
Canned
Mushrooms
Onions (Canned)
Peaches
Pickles
Process Pack
Pimentos
Plums
(1)
Sauerkraut
Canning
Tomato -
Starch, Cheese,
C. SP.
981
33-387
80-393
33-467
175-1030
164-1020
83-574
84-119
60-187
213-363
109-715
BOD5* BOD,-*
2000 - 3000 mg/1 3000 - 5OOO mg/1
Subcategory TSS Subcategory TSS
mg/1 mg/1
9 Carrots 262-1540 12 Cherries,
m Brined 87-130
11 Cherries 18 Dried Fruits
Sweet & Sour 48-125 Prunes Figs 8-568
14 Corn Chips l£50 23 Jams, Jellies
& Preservatives 404-711
21 Grape Press. 90-530 25 Mayonnaise &
Salad Dressings 899-1510
22 Grape Juice 216-228 30 Pears 84-702
31 Peas 79-673 35 Pineapples 837-1160
37 Potatoe 39 Pumpkin and
Chips 1450-3910 Squash 185-1600
BOD5* - Greater Than
5000 mg/1
Subcategory TSS
mg/1
5 Beets 367-4330
13 Corn 131-2440
32 Pickles Fresh
Pack 42-6130
40 Raisins 7-529O
47 Sweet Potatoes 4010-12,200
51 White Potatoes
Whole 1660-24,300
Note: Fruit and vegetable wastes may be nitrogen deficient.
*See Appendix 5 for parameters which may be inhibitory to biological systems.
(l)May have high concentration of dissolved solids.
-------
BOD removal is accomplished with sedimentation, activated
sludge, aerated lagoons, trickling filters, and anaerobic
processes. Some waste streams are nutrient deficient, and
require nitrogen and phosphorus addition.
Advanced waste treatment techniques are also applicable to
wastes from this industry, such as activated carbon, fil-
tration, and electrodialysis. Table 8-3-2 gives the removal
efficiencies for the treatment practices of this industry.
8-3-9
-------
Table 8-3-2
Canned and Preserved Fruits and
Vegetables Industry
Wastewater Treatment Practices
Pollutant and Removal Efficiencies
Method Percent
TSS
Flotation 50-80
Primary Sedimentation 30-75
BOD
Primary Sedimentation 50-80
Biological Treatment 40-99
8-3-10
-------
CANNED AND PRESERVED SEAFOOD
1. General Industry Description
The canned and preserved fish and seafood industry, including
industrial products, has been expanding steadily from the use
of drying and curing techniques to the various technologies
involved in preserving, canning, freezing, and rendering of
fishery products. There is great variability in the length of
processing season and amount of material processed in the
industry. There is also a tremendous variability in both the
amount of water used and the waste loading from process plant
to process plant. In general, wastes from this industry con-
tain BOD, suspended solids, and oil and grease.
This industry includes Standard Industrial Classifications
(SIC) 2091 and 2092.
2. Industrial Categorization
The Catfish, Crab, Shrimp and Tuna segment of the Canned and
Preserved Seafood Process industry has been subcategorized
as follows:
Subcategory Designation
Farm-raised Catfish Processing A
Conventional Blue Crab Processing B
Mechanized Blue Crab Processing C
Non-Remote Alaskan Crab Meat Processing D
Remote Alaskan Crab Meat Processing E
Non-Remote Alaskan Whole Crab & Crab Section Processing F
Remote Alaskan Whole Crab & Crab Section Processing G
Dungeness & Tanner Crab Processing in the Contiguous
States H
Non-Remote Alaskan Shrimp Processing I
Remote Alaskan Shrimp Processing J
Northern Shrimp Processing in the Contiguous States K
Southern Non-Breaded Shrimp Processing in the Con-
tiguous States L
Breaded Shrimp Processing in the Contiguous States M
Tuna Processing N
8-4-1
-------
The remaining segment of the industry has been tentatively
divided into the following subcategories:
1) Fish meal processing
2) Alaskan hand-butchered salmon processing
3) Alaskan mechanized salmon processing
4) West Coast hand-butchered salmon processing
5) West Coast mechanized salmon processing
6) Alaskan bottom fish processing
7) Non-Alaskan conventional bottom fish processing
8) Non-Alaskan mechanized bottom fish processing
9) Hand-shucked clam processing
10) Mechanized clam processing
11) West Coast hand-shucked oyster processing
12) Atlantic and Gulf Coast hand-shucked oyster processing
13) Steamed/canned oyster processing
14) Sardine processing
15) Alaskan scallop processing
16) Non-Alaskan scallop processing
17) Alaskan herring fillet processing
18) Non-Alaskan herring fillet processing
19) Abalone processing
3. Process Description
The processes used in this industry generally include the
following: harvesting, storing, receiving, eviscerating, pre-
cooking, picking or cleaning, preserving and packaging.
Harvesting utilizes some of the oldest and newest technologies
in the industry. It may be considered a separate industry
supplying the basic raw material for processing and subsequent
distribution to the consumer. Harvest techniques vary according
to species, and consist of four general methods: netting, trapping,
dredging, and line fishing. Fishing vessels utilize the latest
technology for locating fish and shellfish and harvest them in
the most expedient and economical manner consistent with local
regulations. Once aboard the vessel, the catch either is
taken directly to the processor, or is iced or frozen for
later delivery.
The receiving operation usually involves three steps: unloading
the vessel, weighing, and transporting by conveyor or suitable
container to the processing area. The catch may be processed
immediately or transferred to cold storage.
8-4-2
-------
Preprocessing refers to the initial steps taken before the raw
material enters the plant. It may include beheading shrimp
at sea, eviscerating fish or shellfish at sea, and other
operations to prepare the fish for butchering.
Wastes from the butchering and evisceration are sometimes dry-
captured, or screened from the waste stream, and processed as
a fishery by-product.
Occasionally, cooking or precooking of crab or tuna may be
practiced in order to prepare the fish or shellfish for picking
and cleaning operation. The steam condensate, or stick water,
from the tuna or crab precook is often collected and further
processed as a by-product.
The fish is prepared in its final form by picking or cleaning
to separate the edible portions from non-edible portions.
Wastes generated during this procedure are sometimes collected
and saved for by-product processing. Depending on the species,
the cleaning operation may be manual, mechanical, or a com-
bination of both. With fresh fish and fresh shellfish, the
meat product is packed into a suitable container and held under
refrigeration for shipment to a retail outlet. If the product
is to be held for extended periods of time before consumption,
several forms of preservation are used to prevent spoilage
caused by bacterial action and autolysis: freezing, canning,
pasteurization and refrigeration.
Bacterial growth is arrested at temperatures below -9 C (16 F).
For this reason, freezing is an excellent method of holding un-
cooked fish for an extended period of time. Freezing is also
advantageous because the meat remains essentially unchanged, in
contrast to canning, which alters the product form. However,
autolysis still continues at a reduced rate, necessitating
the consumption of the meat within approximately 6 months.
Storage times vary from species to species. Cooking of crabs
prior to freezing inactivates many enzymes and further slows
autolysis.
Preservation by canning requires special equipment to fill
the can, preservatives and seasonings, and a partial vacuum
to seal the can. A partial vacuum .is necessary to avoid
8-4-3
-------
distortion of the can due to increased internal pressures
during cooking. After sealing, the cans are washed and
retorted (pressure-cooked) at approximately 115 C (240 F)
for 30 to 90 minutes, depending on the can size. Although
the enzymes are inactivated at rather low temperatures, high
temperatures must be reached to insure the destruction of
harmful anaerobic bacterial spores. Clostridium botulinum, the
most harmful of these, must be subjected to a temperature of
116°C (240°F) for at least 8.7 minutes. A longer cooking time
is employed to achieve this temperature throughout the can and
to insure total destruction of the bacteria. After the cook,
the can is cooled with water and the canned fish or shellfish
is transported to the labeling room for casing and shipment.
Industrial fishery products include such commodities as fish
meal, concentrated protein solubles, oils, and also miscellaneous
products including liquid fertilizer, fish feed pellets, kelp
products, shell novelties and pearl essence. The major fish
species used for producing industrial fishery products are the
Atlantic menhaden and the pacific anchovy.
Meal, oil, and solubles are extracted from the fish via a
wet reduction process. This process consists of cooking the
fish with live steam at about 240°F. The cooked fish are
then pressed, separating the fish into press cake (solids)
and press liquor (liquid). The press cake is dryed, ground
and sold as fish meal. The press liquor is clarified and the
oil is separated. The oil is then further refined, stored and
shipped. The de-oiled press liquor, known as stickwater, is
usually evaporated to about 50 percent solids and sold as
fish solubles.
4. Wastewater Characterization
Table 8-4-1 contains raw wastewater characteristics for the
industry. Pollutant parameters of concern are BOD, COD, TSS
and oil and grease.
5. Control and Treatment Technology
In Plant Control - The major in plant control for this industry
is the recovery of what is now wasted food stock. Much of the
fish harvested is wasted even though it contains valuable pro-
tein which can be used for human or animal consumption.
8-4-4
-------
TABLE 8-4-1
RAW WASTEWATER CHARACTERISTICS
CANNED AND PRESERVED SEAFOOD PROCESSING INDUSTRY
SUBCATEGORY
Farm-Raised Catfish
Conventional Blue Crab
Mechanized Blue Crab
Non-Remote Alaskan Crab Meat
and
Remote Alaskan Crab Meat
Non-Remote Alaskan Whole Crab & Crab
Section
and
Remote Alaskan Whole Crab and Crab
Section
Dungeness and Tanner Crab
Non-Remote Alaskan Shrimp
and
Remote Alaskan Shrimp
West Coast Shrimp
Southern Non-Breaded Shrimp
Breaded Shrimp
Tuna Processing
Fish Meal
All Salmon
Bottom and Fin Fish (All)
All Sardines
All Herring
Hand Shucked Clam
Mechanized Clam
All Oysters
All Scallops
Abalone
Flow
GPD
21M-45M
700
20M-73M
65M-99M
36M-84M
38M-74M
300M-400M
90M-160M
180M-240M
150M-200M
65M-3.6MM
92M-10M1
58M-500M
6M-400M
80M
29M
86M-170M
300M-3MM
14M-320M
1M-115M
10M-14M
BOD
mg/1
340
4400*
600
270
330
280-1200*
1M*-2M*
2000*
1000*
720*
700*
100-24M1*
253-2600*
200-1000*
1300*
1200*-6000*
800*-2500*
500-1200*
250-800*
200-10,000*
430-580
COD
mq/1
700
6300*
1000
430
710
550-2000*
2M*-3 . 7M*
3300*
2300*
1200*
1600*
150-42M1*
300-5500*
400-2000*
2500*
3000*-10,000*
1000-4000*
700-1500*
500-2000*
300-11,000*
800-1000
TSS
mq/1
400
620
330
170
210
60-130
1.3M-3M
900
800
800
500
70-20M1
120-1400
100-800
921
600-5000
600-6000
200-400
200-2000
27-4000
200-300
Oil &
Grease
mcr/1
200*
220*
150*
22
30
28-600*
100*-270*
700*
250*
-
250*
20-5M1*
20-550*
40-300*
250*
600*-800*
16-50
20-25
10-30
15-25
22-30
NOTES:
1 Higher range is for bailwater only
* - See Appendix C for parameters which may be inhibitory to biological systems
M 1,000
MM= 1,000,000
Seafood processing wastewater may contain high concentrations of chlorides from
processing water and brine solutions, and organic nitrogen (0-300 mg/1) from
processing water.
8-4-5
-------
There are also non-edible parts of fish such as the shells
of shrimp and crab which contain chitin which can be recovered
as a valuable product.
There are three major in-plant changes that would facilitate
the recovery of now wasted valuable protein:
a) Minimizing the use of water (thus minimizing loss of solubles)
b) Recovery of dissolved proteins in effluent solutions
c) Recovery of solid portions for use as edible products.
The use of water may be minimized sometimes by substituting pneu-
matic transporting systems for water transporting systems. Another
water saving technique is the use of spring loaded hose nozzles
that automatically shut off when released by the operator.
Presently hoses are frequently left running when not being used.
Protein can be recovered by use of one of the following
techniques:
a) Conventional Reduction Processes
b) Protein Precipitation from Effluent Streams
c) Solids Recovery
Treatment Technology
The first major consideration in the design of treatment equip-
ment is that solids removal should occur as quickly as possible.
The longer the detention time between waste generation and
solids removal the greater the BOD and COD and the smaller the
by-product value.
Solids separation is generally accomplished by screening and
sedimentation.
Other methods of treatment available to this industry consist of
the following:
a) Activated Sludge
b) Trickling Filters
c) Aerated Lagoons
d) Land Disposal
e) Physical/Chemical Treatment such as
Air Flotation
Table 8-4-2 provides a summary of removal efficiencies for some
of these treatment techniques.
8-4-6
-------
TABLE 8-4-2
CANNED AND PRESERVED SEAFOOD INDUSTRY
WASTE WATER TREATMENT PRACTICES
Pollutant and Method
BOD
Flotation
Biological Treatment
TSS
Sed imentat ion
Flotation
Removal Efficiency, Percent
50-65
80-90
50-70
30-87
COD
Flotation
50-75
8-4-7
-------
SUGAR
1. General Industry Description
The sugar processing industry includes the processing of raw
cane sugar, the refining of liquid and crystalline cane sugar,
and the processing of beet sugar. Cane sugar refineries
produce either a white crystalline or a clear liquid sugar from
unrefined raw sugar. Molasses is produced as a by-product.
The raw materials for beet sugar processing are sugar beets,
limestone, and small quantities of sulfur. The products are
refined sugar, beet pulp and molasses.
The principal water usage in the cane sugar refining segment
of the industry consists of barometric condenser cooling water,
filter cake slurry, char wash, carbon slurries, boiler makeup,
affination (wash) water, and ion exchange regeneration. In
the beet sugar processing segment, water is used for six prin-
cipal purposes: transporting or fluming beets to the processing
operation, washing beets, processing (extracting sugar from
beets), transporting lime mud cake waste, condensing vapors
from evaporators and crystallization pans, and cooling. The
sugar processing industry is covered by Standard Industrial
Classification (SIC)2063.
2. Industrial Categorization
The sugar processing industry is broadly subdivided into two
main categories: canesugar processing and refining, and beet
sugar processing. Raw cane sugar processing is not covered in
this discussion since these plants generally do not discharge
into POTW's. Therefore, for the purposes ,of raw waste charac-
terization and delineation of pretreatment information, the
industry has been further subdivided into the following three
subcategories:
Subcategory Designation
Crystalline Cane Sugar Refining (A)
Liquid Cane Sugar Refining (B)
Beet Sugar Processing (C)
3. Process Description
Crystalline Cane Sugar Refining (A)
The refinery receives raw crystalline sugar produced by the
cane sugar factories. Raw sugar consists primarily of sugar
crystals and various impurities which may include bagasse
8-5-1
-------
particles, organics, inorganic salts, and microorganisms.
Sugar refining may be defined as the removal of the molasses
film layer and associated impurities from the surface of the
raw sugar crystals. The crystalline raw sugar is washed to
remove part of the molasses film, then placed into solution,
taken through various purification steps, and finally recrys-
tallized. Figure 8-5-1 contains a process flow diagram for cane
sugar refining.
Raw sugar crystals are placed in a magma mingler, (a mixer) in
which magma (sugar syrup) is heated in order to facilitate
loosening the molasses film from the raw sugar. The magma is
fed into centrifugals which separate the syrup and molasses
from the sugar. Hot water is added to wash the sugar which is
then melted and screened. The remaining suspended and colloidal
matter present in the melt liquor is removed by clarification.
Clarification may involve coagulation and either flotation
clarifiers or pressure filtration. The muds, scums, and filter
muds produced in clarification contain significant sugar con-
centrations which must be recovered. The press cake is usually
handled in a dry form and taken to landfill but may be slurried
and sewered. After affination (washing) and clarification, the
sugar liquor still contains impurities and color which are
removed by adsorption.
Decolorization is accomplished by filtering sugar liquor through
one of a variety of adsorptive materials including bone char,
granulated activated carbon, powdered activated carbon,
vegetable carbon, and ion exchange materials. After some period
of operation, the decolorization ability of these materials
decreases and they must be washed and regenerated. Sugar is
recovered from the washwaters and the effluent is discharged.
Granular carbon refineries use water for transporting the
carbon. Transport water is reused but must be discharged
periodically due to bacterial growth.
The final steps of recystallizing and granulating are essen-
tially the same in all refineries. Recrystallization is per-
formed by concentration of the decolorized sugar liquor and
sweet water in continuous-type evaporators which are heated by
steam, placed under vacuum, and operated in a series of several
units. Short tube or calandria type evaporators are commonly
used to achieve double or triple effect evaporation, although
the Lillie film evaporator is also used in some installations.
8-5-2
-------
Raw Sugar Hot Water
H1NGLER » CENTRIFUGALS »-|MELTER j - CLARIFICATION
4 ...J | 1
Mingling Syrup HLIKAI10N -* '
Cake .. FILTRATION
| Disposal ' 1 '
Scum and J
C.ke U.sposa, DECOLORIZATION
1
«J> EVAPORATION
1
VACUUM PANS
,,
Final 1
| CENTRIFUGATIOH
Molasses " |-"
GRANULATION
PACKAGING
OR
STORAGE
Raw Sugar
*
[ AFFINAT10N
MEL
Steam
Tlfir- ^ Water
SWEET WATER
M
,_
| CLARIFICATION
i »J FILTRATION _ "
1 *
| GRANULAR CARBON j
4
I ION EXCHANGE
i ' i
Water
EVAPORATE" ^ fc HOT WATER
Carbon
T
^ *~| FILTRATION ^
Dlatomaceous Earth
| INVERSION
*
.
CRYSTALLINE CANE SUGAR REFINING
Refined Sugar
LIQUID SUGAR REFINING
FIGURE 8-5-1
CANE SUGAR REFINING
-------
Vapors from the last stage are condensed by one of several con-
denser designs, but all operate on the principle of relatively
cold water passing through a cylindrical vessel, contacting
the hot vapors, and condensing them. After concentration in
evaporators, the sugar liquor and sweet waters are crystallized
in single-effect, batch type evaporators called vacuum pans.
Calandria pans are commonly used and are similar to the calan-
dria evaporators except that the pans have larger diameters
and shorter tubes in order to handle a more concentrated liquid.
Finished crystalline sugar is produced by granulating and
screening, and transported to conditioning silos prior to
packaging or bulk shipment.
The principal wastewater streams in a crystalline cane sugar
refinery are the barometric condenser cooling water, filter
cake slurry, char wash, carbon slurry, truck and car wash,
and floor wash. The condenser cooling water constitutes
the largest volume of, water used in a cane sugar refinery.
Liquid Cane Sugar Refining (B)
The initial refining steps of affination, decolorization, and
evaporation in a liquid sugar refinery are essentially the same
as described above for a crystalline sugar refinery. Since
liquid sugar refineries do not recrystallize their primary
product, the necessity of using vacuum pans is preempted,
although some refineries use vacuum pans for the crystallization
of remelt sugar, producing molasses as a by-product. After
evaporation, the sugar solution is filtered and cooled and
then sent to storage as liquid sugar. It may also be inverted
to a specific degree and stored separately in stainless
steel clad tanks equipped with ultra-violet lamps and air
circulation filters to insure sterilization. The filtration
and inversion processes are the same as those used in the
formation of liquid sugar by the melting of crystalline sugar. A
process flow diagram for liquid sugar refining is shown in
Figure 8-5-1.
Because crystal formation is not a part of primary liquid
sugar production, water usage to process the same quantity
of raw cane sugar into liquid sugar is substantially smaller
compared to the processing of crystalline sugar.
8-5-4
-------
Beet Sugar Processing (C)
The raw materials for beet sugar processing are sugar beets,
limestone, small quantities of sulfur, fuel and water. The
products are refined sugar, dried beet pulp, and molasses.
The basic steps for beet sugar processing consist of slicing,
diffusion, juice purification, evaporation, crystallization,
and recovery of sugar. A process flow diagram is shown in
Figure 8-5-2.
Beets are delivered to the plant by trucks or railroad cars
and stored in large piles or pumped directly into flumes for
transport into the processing plant. The water flumes are
provided with rock catchers which trap and remove stones
and other heavy foreign material from the flume flow. The
beets are next lifted from the flume to a washer by a beet
wheel. The washed beets are sliced into thin ribbon-like
strips called "cosettes", and fed into a continuous diffuser
which extracts sugar and other soluble substances from the
cossettes under a counter-current flow of water. The "raw
juice" containing the sugar and other soluble substances is
pumped to purification stations. The exhausted beet pulp is
conveyed to pulp presses where its water content is reduced
before being fed into pulp driers. Dried pulp is utilized as
a base for livestock feed.
The raw juice from the diffusers is pumped to the first
carbonation station. Lime, slaked lime, or calcium saccharate
(from the Steffen process) is added and the juice is then
saturated with carbon dioxide gas to precipitate calcium
carbonate. The sludge thus formed is separated from the
mixture by vacuum filters. The "thin juice", after further
treatment with carbon dioxide, filtration, and sulfur dioxide
to reduce the pH to about 8, is concentrated in multiple-
effect evaporators to a "thick juice" and then boiled in a
vacuum pan crystallizer to obtain the crystallized sugar.
The sugar is separated by centrifugation from the adhering
syrup and dried. The remaining syrup is further concentrated
to yield additional sugar and molasses. The molasses may be
added to the exhausted beet pulp or further desugarized by
the Steffen process where the molasses is diluted, cooled and
treated with calcium oxide to precipitate the sugar as a
saccharate. The calcium saccharate, after separation by fil-
tration from the remaining solution of impurities, is
8-5-5
-------
[RAW WATER] BEET STORAGE
rL
\
11 PLUMING I
ISLICERSJ
1 DIFFUSER [
^
LI
CARB<
/
DNATION
\
[FILTERS)
[CRYSTALLIZER
1 CENTRIFUGE |
CLARIFIER OR!
SETTLING I
' POND
'-« 1
f PULP PRESSES ]
^ F 1
[DRIER j
^RIED PULP)
i
- 1
SACCHARATE MILK f
f\ ^_ LIME «
/COOLING\
_ 1 DEVICE \ f"\
1 OR 1
VHOLDING /
XyPOND/
^"1 MOLASSES
li r*
GRANULATION
I EVAPORATOR
| CSF~]
I SUGAR |
CONTINUOUS OR
INTERMITTENT DISCHARGE
TO SURFACE WATERS
FIGURE 8-5-2
FLOW DIAGRAM FOR A BEET SUGAR PROCESSING PLANT
WITH SUBSTANTIAL IN-PROCESS RECYLE AND REUSE
8-5-6
-------
returned to the first carbonation station. Principal waste-
water streams from a beet sugar processing plant consist of
flume water, barometric condenser cooling water, pulp, mass
and pulp screen water, lime cake slurry, and Steffen waste.
4. Wastewater Characterization
Wastewater characteristics of total effluents from each of
the three subcategories of the sugar processing industry are
shown in Tables 8-5-1 and 8-5-2.
5. Control and Treatment Technology
In-Plant Control - Significant in-plant control of both waste
quantity and quality is possible for all three subcategories
of the sugar processing industry. Important control measures
in the cane sugar refining segment (A, B) of the industry
include the prevention of sugar loss, improved techniques for
dry-handling of sludges and filter cakes, maximum recovery
and reuse of various process streams, and improved housekeeping
practices. The unloading of raw sugar at the receiving area
of a cane sugar refinery is often accompanied by sugar spillages,
and the periodic washdown of the area produces a variable
waste stream with a high content of sugar and BOD . Minimi-
zation of sugar spillage through equipment modification and
the recovery of as much spilled sugar as possible by sweeping
and improved housekeeping practices can essentially eliminate
all sugar loss and the resulting pollutant load from the
receiving area. A similar pollutant load resulting from truck
and car wash can be minimized by maximizing the recovery of
sucrose concentration from this waste stream for processing.
Reduction of sucrose entrainment in the barometric condenser
cooling water is a highly significant control measure. Baro-
metric condenser water constitutes over 80 percent of the total
water usage at cane sugar refineries (A, B), and sucrose
entrainment represents an economic loss to the refiners as
well as an organic pollutant load in the effluent. In
calandria-type vacuum pans and evaporators, the vapor height
should be at least 250 percent of the height of the calandria
tubes to minimize entrainment. Where existing heights are
insufficient, they can be increased by installing a spacer in
the existing equipment. The liquid level in the vacuum pans
and evaporators should be maintained near the design level.
In addition to proper design and operation, a number of devices
can be installed to separate liquid droplets from the vapors.
8-5-7
-------
TABLE 8-5-1
SUGAR PROCESSING INDUSTRY
RAW WASTEWATER CHARACTERISTICS
Crystalline
Cane Sugar
Liquid
Cane Sugar.
Beet Sugar
Parameter
Flow
Flow
BOD5
TSS
TDS
COD
NH3 ~
Kjel
N0_ -
Range
Type
(mg/1)
(mg/1)
(mg/1)
(mg/1)
N (mg/1)
- N (mg/1)
N (mg/1)
Refining * '
A
B
13-263
2-397
966 2
36-460
0.462
0.60 - 1.66
4.332
Refining * '
B
B
72-487
59-796
1,014*2
190-579
0.032
0.512
Processing
C
B
857*
3,216
1,550*
Note:
* See Appendix 5 for parameters which may be inhibitory
to biological systems
B-Batch Process
(1) These concentration ranges include both process wastewater
and barometric condenser cooling water. Generally barometric
condenser cooling water would not be discharged to a POTW,
and consequently the pollutant values indicated would be
correspondingly lower.
(2) Based on data from one plant only.
8-5-8
-------
TABLE 8-5-2
SUGAR PROCESSING INDUSTRY
RAW WASTEWATER CHARACTERISTICS
BASED ON PRODUCTION
Parameter
Crystalline
Cane Sugar
Refining(1'
A
Liquid
Cane Sugar
Refining^ '
B
Kjel - N(kg/kkg) 0.01-0.08
NO - N (kg/kkg) 0.212
0.01
Beet Sugar
Processing
C
Flow Range
dAkg)
Flow Type
BOD (kgAkg)
TSS (kg/kkg)
TDS (kg/kkg)
COD (kg/kkg)
XTTT »T /I /1_1
3, 300, -64, 000
B
0.63-2.4
0.06-12.5
46. 92
1.5-17.1
10,000-3.0,000
B
2.2-5.1
0.94-8.4
16. 22
5.7-6.6
n 2
23,352
B
20.0
55.8-94.1
70.0
Note: 1/kkg - liters of flow/1000 Kg product produced
kg/kkg - kilograms/1000 kg product produced
B - Batch Process
(1) These concentration ranges include both process wastewater
and barometric condenser cooling water. Generally barometric
condenser cooling water would not be discharged to a POTW,
and consequently the pollutant values indicated would be
correspondingly lower.
(2) Based on data from one plant only.
8-5-9
-------
Baffle arrangements, which operate on either centrifugal or
impingement principles, and demisters, which are essentially
wire mesh screens serving the dual purpose of impingement
and direction change, are examples of such devices. The use
of partial surface condensers as heat exchangers in the
exhaust ducts prior to barometric condensation is another
entrainment control measure. These units not only affect
liquid-vapor separation but also capture heat from the vapors.
Most refineries use pressure filters such as the valley or
industrial type for removing impurities from sugar liquors.
In these refineries, a major portion of the filter cake can
be recovered in a kiln by revivification of the filter aid.
In the beet sugar processing subcategory (C), important in-
plant control measures include the proper handling of sugar
beets, design of beet flume systems to facilitate dry-handling
techniques, process water reuse, dry-handling of lime mud
cake, conversion of Steffen filtrate to usable end-products,
and the recovery and reuse of various flows in the plant.
Removal of soil, leaves, and trash from the sugar beets in
the field and delivery of the cleanest possible raw product
to the plant is highly desirable. Without adequate control
measures, late season irrigation and wet-field harvesting
contribute to increased waste treatment needs and cost of
settling devices in complete recycle flume water systems.
Deterioration of sugar beets during storage should be mini-
mized by maintaining proper conditions in the stockpiles and
reducing storage time. Waste loads imposed upon the beet
flume system can be reduced by minimizing the contact time
between the sugar beets and the flume water or by the adoption
of dry handling procedures. The typical flume water recy-
cling system is a relatively inexpensive means of providing
treatment for reuse and retention of flume water. The reuse
of process wastewater (pulp press water, pulp transport water,
wet pulp screen water) is an important control measure.
Process waters can be reused for a variety of plant needs or
returned to the diffuser. Pulp transport water can be
eliminated by a dry conveyor system which moves exhausted
pulp to the presses. Problems of fermentation and noxious
odors associated with the long-term holding of lime mud wastes
can be minimized by using shallow pond depths or aeration.
Wastewaters associated with the barometric condensing opera-
tion can be reused as diffuser makeup water, raw water supply,
beet flume recirculation makeup, lime mud slurrying water
and gas wash water.
fi-5-10
-------
Treatment Technology
The various wastewater treatment practices for each of the
three subcategories of the sugar processing industry are sum-
marized in Table 8-5-3. The standard practice for urban cane
sugar refineries, which represent about three-fourths of U.S.
refined cane sugar production, is to discharge all waste
streams other than barometric condenser cooling water to
municipal treatment plants. However, it should be noted that
direct discharges employ biological treatment of process
water with or without blowdown from the barometric condenser
cooling water recirculatipn system. Rural refineries generally
have available land for impoundment, and total or partial
wastewater retention is the standard practice. In beet sugar
processing plants, treatment practices vary from little
treatment to storage and land disposal of all wastes.
8-5-11
-------
TABLE 8-5-3
SUGAR PROCESSING INDUSTRY
WASTEWATER TREATMENT PRACTICES
(Percent Removal)
Parameter & Practice
BOD
1. Total impoundage of all
wastewaters 100
2. Impoundage of process wastewater 82
3. Dewatering and dry hauling of
filter slurry 26
4. Screening, settling, and recycle
of flume water, with mud drainoff to
holding ponds for land disposal
5. Biological treatment of process
wastewater 77
6. Biological treatment of process
wastewater and barometric condenser
blowdown 95
TSS
1. Total impoundage of all wastewaters 100
2. Impoundage of process wastewater
3. Dewatering and dry hauling of
filter slurry
4. Biological treatment of process
wastewater
5. Biological treatment of process
wastewater and barometric condenser
blowdown 99.6
TDS
1. Total impoundage of all wastewaters 100
COD
1. Total impoundage of all wastewaters 100
Nitrogen
1. Total impoundage of all wastewaters 100
Crystalline Liquid
Cane Sugar Cane Sugar Beet Sugar
Refining Refining Processing
A B C
100
82
26
91
96
100
100
86
99
100
100
86
98
100
99.7
100
100
100
96
100
100
100
100
8-5-12
-------
TEXTILES
1. Industry Description
The textile industry involves the manufacture of fabrics
from wool, cotton, and synthetic fibers; the synthesis or
spinning of synthetic fibers is not included in this group,
but rather is included under synthetic organic chemicals.
The industry's basic raw materials are wool, cotton, and man-
made fibers. Of the three major textiles, wool represents the
smallest market and synthetic textiles the largest. The natu-
ral fibers are supplied in staple form (staple being short
fibers). The man-made fibers are supplied as either staple
or continuous filament. In either case, the fiber is spun into
yarn which is simply a number of filaments twisted together.
The yarn is woven or knitted into a fabric and the fabric then is
dyed and treated to impart such characteristics as shrink re-
sistance, crease resistance, fireproofing, etc. The finished
fabric is delivered (directly or through converters, jobbers, and
wholesalers) to the manufacturer of textile products.
This industry comprises the manufacturing activities listed under
Standard Industry Classifications (SIC) 225, 226, 227, 228, 2211,
2221, 2231, 2241, 2295, 2296, 2297, 2298, 2299.
2. Industry Categorization
A useful categorization for the purposes of raw waste charac-
terization and the establishment of pretreatment information are
the following subcategories:
Process Designation
Wool Scouring A
Wool Finishing B
Dry Processing C
Woven Fabric Finishing D
Knit Fabric Finishing E
Carpet Mills F
Stock and Yarn Dyeing and
Finishing G
Commission Finishing H
8-6-1
-------
3. Process Description
Figure 8-6-1 is a flow diagram for the textile industry show-
ing the processes described below.
Wool Scouring (A)- Wool is a natural fiber of sheep origin
and contains many impurities which must be removed before fur-
ther use. Wool scouring, shown in Figure 8-6-2, is the proc-
ess that converts the raw wool into cleaned wool yarns. After
the fleece is sorted, it is carried through a series of scour-
ing bowls where scour liquor flows countercurrent to it. De-
tergent is added to emulsify greases and oils. The scoured
wool is dried and converted into wool top. The scour liquor
contains significant quantities of oil and grease which does
not appear to be readily biodegradable. It also contains
materials derived from sheep urine, feces, blood, tars, brand-
ing fluids and insecticides, as well as grit. A grease re-
covery step is important to reduce pollution. Two methods
are commonly used: centrifuging and acid cracking.
In centrifuging, the lowest density stream contains concen-
trated grease, which is recovered; the medium density stream
is recycled as fresh scour liquor; the high density stream
consists mainly of dirt and grit, and is sent to the treatment
plant.
An alternative means to break the grease emulsion for wool grease
recovery is the acid-cracking grease recovery system. The
grease is recovered and the liquor is then neutralized and sent
to the treatment plant.
Wastewaters contain significant quantities of oil and grease
even after in-process recovery.
Wool Finishing (B) - The process flow diagram is shown in
Fig. 8-6-3. This process converts wool fibers into finished
wool fabric with washing, dying, weaving, knitting and the inter-
mediate steps. Wool finishing has a higher water usage rate
than any other fiber finishing category. Heavy scouring is
the term applied to the washing of the fabric by the use of de-
tergents, wetting agents, ejnulsifiers, alkali, ammonia, or other
washing agents. The purpose of this heavy scour is to remove
oils, grease dirt, etc. This process is one of the most impor-
tant steps in wool finishing because if all of the foreign mate-
rials are not completely washed out, the finished fabric is sus-
ceptible to rotting, smelling, and bleeding, and will not accept
dyes uniformly. Heavy weight, closely woven fabrics with a high
percentage of recycled wool require very heavy detergents, long
wash times and extensive rinsing to clean the goods. High or-
ganic and hydraulic loadings are associated with this type
of fabric.
8-6-2
-------
Raw Wool
00
I
01
(A)
Wool Scouring
Finishing
(F)
Carpet Mills
(G)
Stock and Yarn
Dyeing & Finishing
-> Wool Yarn-
-> Wool Top '
(B)
Wool Finishing
Finished Wool Fabric
Lanolin
:otto
n
fe
Dry Processing
(D)
Woven . Fabric
Finishing
(E)
p- L-dipeu uuLting
Finished Woven Fabric
Finished Knit Goods
Carpet
Finished Yarn or Stock
FIGURE 8-6-1
TEXTILE MANUFACTURING
-------
00
I
Source: "Chemical Physical and Biological Treatment of Wool Processing Wastes," by Hatch, et al. 28th Annual Purdue Industrial
Wasle Conference. West Lafayette. Indiana. 1 May 1973.
FIGURE 8-6-2
WOOL SCOURING (A)
TEXTILE INDUSTRY
-------
00
I
CT>
I
Ul
I Yarn Dvepn(3 /
= Solid Wastes
FIGURE 8-6-3
WOOL FINISHING (B)
TEXTILE INDUSTRY
-------
Light open goods with a low percentage of wool generally scour
easily and result in lower organic and hydraulic discharges.
Carbonizing consists of soaking the fabric in sulfuric acid,
in order to oxidize any contaminants. The acid bath is dis-
charged when it becomes too contaminated for further use,
about once every two days.
Fulling is usually used on 100% woolen fabrics to stabilize
the dimensions of the wool. Though it is essentially a dry
process, it is followed by extensive rinsing to prevent rancid-
ity and wool spoilage. This step produced over 50% of the
hydraulic load in one wool mill investigated.
The more commonly used dyes for wool or wool blends are acid
dyes or metallized dyes, and a small amount of chrome may be
expected in the effluent. In the dyeing process, generally
90% or more of the dye is exhausted, and the dye bath is dis-
charged to the sewer. Since the dyes are very expensive, ef-
fort is made to assure as high an exhaustion level as possible.
After the fabric is dyed and rinsed, finishing agents may be
applied, such as mothproofing, soil repellents and fire retard-
ents. Any of the finishing chemicals can appear in the waste-
water when equipment is washed.
Dry Processing (C) - Dry processing textile operations include
products and processes which by themselves do not generate large
discharges. Some operations include yarn manufacturing, yarn
texturizing, unfinished fabric manufacture, fabric coating,
fabric laminating, tire cord and fabric dipping, carpet tuft-
ing, and carpet backing. The principal source of effluent from
such processes is the washing and cleaning of equipment.
A process flow diagram is shown in Figure 8^6^4. The only liquid
waste shown is derived from washouts from the slashing or siz-
ing operation. Prior to being woven, the yarns are coated with
a sizing material to give the yarn lubrication and strength
that will permit it to withstand the severe mechanical demands
of weaving. Cottons are generally coated with starch and syn-
thetics with polyvinyl alcohol. Wool and wool blends are seldom
sized. The wastewater generally represents a low percentage of
the total plant flow.
8-6-6
-------
oo
9i
I
Cotton-
Polyester
Woven
Fjhncs
To Yarn Dyeing and
Finishing (Cat x-
To '.'.'oven Fabr
-------
Woven Fabric Finishing (D) - A process flow diagram is shown
in Figure 8-6-5. Wet Processes which are used in finish-
ing woven -fabric may be divided into two groups:
1. Those used to remove impurities, clean or modify the
cloth.
2. Those in which a chemical is added to the cloth.
The first of these groups includes desizing, scouring, bleach-
ing, mercerizing, carbonizing, and fulling. The second group
of processes includes dyeing, printing, resin treatment,
waterproofing, flame proofing, soil repellancy, and special
finishes.
Desizing, or the removal of starch or polyvinyl alcohol, gen-
erates starch solids , or polyvinyl alcohol, fat or wax, dis-
solved solids, suspended solids and some oil or grease. The
pH may be neutral or very low depending on the desizing meth-
od. The wastewater is generally biodegradable. Biological
waste systems can develop organisms acclimated to polyvinyl
alcohol (sizing agent) which degrade this chemical rapidly
and completely-
Scouring cotton to remove impurities generates a strongly
alkaline wastewater. It is generally dark-colored and contains
significant levels of dissolved solids, oil and grease, and a
modest amount of suspended solids. Scouring of synthetic wov-
en goods generates a low level of dissolved solids from sur-
factant, soda ash, or sodium phosphate.
Mercerization swells the cotton fibers as alkali is absorbed
into them to provide increased tensile strength and abrasion
resistance. The fabric is fed through a series of alkali
baths and then washed to remove the caustic. Mercerization
wastes are predominantly the alkali used in the process. The
waste stream contains high levels of dissolved solids, and
may have a pH of 12 to 13. Small amounts of foreign mater-
ials and wax may be removed from the fiber, and will appear
as suspended solids and wax in the wastes; these materials
will contribute a small BOD load. In most mills, caustic soda
is recovered and concentrated for reuse, thus saving chemical
and avoiding a sizeable waste load.
Bleaching with either hydrogen peroxide (H_02) or sodium chlor-
ite (NaOCl) and subsequent washing contributes very small waste
loads, most of which are dissolved solids.
8-6-8
-------
WOVEN FABRIC FINISH (Pi
f D-i
I if n
t
t
t \
t I
* 5«c
nilBv<
LW
Uf
ih
/o
(^
1
V* \
1
fun J
VVt'l 9n\
Qjlh t,n.*h.->j
Liquid Wllttl
KNIT FABRIC FINISHING (E)
HV I Si I
Stock, a,nd Yarn Dyeing and Finishing (G)
FIGURE 8-6-5
TEXTILE FINISHING
TRyTTT.E TMHTISTRY
8-6-9
-------
Dyeing is the most complex of all textile finishing processes.
When textiles are dyed, a sufficient amount of the dyestuff
is used to make the shade. Various other chemicals may be used
to help deposit the dye, or to develop the color. Dye loadings
vary widely, depending upon the weight of fabrics being treated
and the depth of color desired. The range of chemicals employed
in dyeing also varies widely from place to place and operation
to operation, and depends substantially upon the dictates of the
marketplace. Dyed goods are generally washed and rinsed to re-
move excess dye and chemicals from the cloth. Dyeing processes
contribute substantially to textile wastes. Color is an obvious
waste. A high level of dissolved solids is expected. Suspended
solids should be low. Carriers, which are essential for dyeing
polyester have high BOD. Plants using sulfur dyes will contain
sulfides in the raw waste. The use of controls could minimize
pollutants.
Printing involves application of dyes or pigments in the form of
a pattern on to fabric. Dyes penetrate and color the fiber; pig-
ments are bonded to the fabric with a resin. In addition to
the dyes, auxiliary chemicals and thickeners are used depending
apon the dye type and the fibers used. Printing wastes will con-
tribute to BOD. Much of the wastes come from the cleaning of
tanks and equipment. These relatively concentrated wastes may
justify segregated treatment, perhaps by incineration.
Finishing-Special finishes such as resin treatment, waterproof-
ing, flameproofing, and soil release endow the fabric with a
particular property desired by consumers. The range of chemicals
is very broad. However, the amount of wastes are generally
small since the chemicals are applied with little water use.
Knit Fabric Finishing (E) - Plants manufacturing knit fabrics
are the source of finished knit piece or yard goods for the
apparel, industrial and household goods trades, and also serve
to augment supplies of fabric to underwear and outerwear manu-
facturers. A process flow diagram is shown in Figure 8-6-5.
Fabrics may be knitted from dyed or undyedyarns. Fabrics
knitted from dyed yarn are scoured or dry cleaned to remove
knitting oils before dyeing -and/or printing. The types of dye-
stuffs, auxiliaries, and conditions employed for dyeing knit
goods are essentially the same as for woven goods (D) '. The main
differences between knit (E) and woven (D) fabric processing
operations are that knit yarns are treated with lubricants rath-
er than with the starch or polymeric sizes used for woven goods
8-6-10
-------
yarns, and that mercerizing operations are not employed with
knit goods. Otherwise, the character of the wastes are simi-
lar to woven fabrics (D).
Carpet Mills (F) - The carpet industry wastes are very similar
to those from Category E. When polyester is dyed, the carriers
present a problem. Although steps are being taken to produce
polyester fiber that can be dyed without carriers, disposal of
carrier still remains a problem. The pH of carpet wastes is
usually close to neutral. The hot dye wastes sometimes pres-
ent a problem to biological treatment systems. The color prob-
lem is similar to that of other finishing categories. Where
carpets are printed or dyed continuously, the thickeners pres-
ent a high BOD load, as in fabric printing.
Carpet yarn is generally dyed in another mill and then brought
to the carpet mill. The yarn is tufted onto a backing in a
dry operation. Washing to remove residual dye, acid, thicken-
ers, and other additives follows. Substantial amounts of dyes
and chemicals may be in the effluent. The carpet is then ready
for application of the backing. A process flow diagram is shown
in Figure 8-6-6.
Stock and Yarn Dyeing and Finishing (G) - In this subcategory
crude yarn is obtained from a spinning facility. The yarn may
be natural, synthetic, or blended. Wet processes used by yarn
mills include scouring, bleaching mercerizing, dyeing and fin-
ishing. Wastes generated will depend upon whether natural fibers,
blends, or synthetics are processed. A process flow diagram is
shown in Figure 8-6-5.
When synthetics are handled, only light scouring and bleaching
is required, and wastes would contain low levels of BOD and dis-
solved solids. Dyeing would contribute a stronger waste, due to a
carrier in the case of polyester and to some acetic acid. These
wastes, of course, would also contain some color.
Scouring, bleaching, and mercerizing of cotton generate BOD and
color because of the fiber impurities; and a level of dissolved
solids because of the mercerizing.
Commission Finishing (H) - Commission finishing plants may
process raw materials into products in any of the above textile
subcategories. The common denominator is that these plants
greige goods on a commission basis. The main difference between
these plants and those, of other subcategories is their ability
to control the fabrics and finishing specifications demanded.
Because "commission house" is an economic description of a
plant, some "commission houses" can control the processing
fabrics and are not characterized by extreme variability in
8-6-11
-------
Predyed Yarn
FIGURE 8-6-6
CARPET MILLS (F)
TEXTILE INDUSTRY
-------
waste load and waste composition. Other "commission houses"
cannot control the scheduling and flow of material through the
plant, and these operations are characterized by an extremely
high variability in waste load and composition. Thus, commis-
sion finishing subcategory plants are defined as manufacturers
of textile materials owned outside their organization. Further-
more, commission finishing subcategory plants must produce 20
percent or more of their commission production from batch
operations and process 50 percent of their commission orders
in lots of 5,000 yards or less.
4. Wastewater Characterization
Textile wastes are generally colored, highly alkaline, high in
BOD, suspended solids, coliform, and high in temperature. Some
colors are water soluble and some are not. Biodegradibility is
highly variable. Metals are used in some dyeing operations of
the industry such as copper and chromium. Small amounts of
zinc and magnesium salts may enter the waste stream from proces-
ses that produce durable press goods. Plants using sulfur dyes
will discharge sulfides.
Wastewaters from commission finishing operations are generally
similar to those produced by the finishing operations of the
other subcategories. However, the treatability of these wastes
is lower. This is due to the use of batch processing, rather
than continuous processing, which requires more water; changes
in raw materials being processed producing variable waste
characteristics; extra rinses required between changes in raw
material which increases the volume of discharge; and the
finishing of special or "problem" materials, which require
extra processing operations.
Tables 8-6-1 and 8-6-2 show textile wastewrter characteristics.
5. Control and Treatment Technology
The control and treatment technology can be divided into two
broad categories: in-process and end-of-pipe. Figure 13-6 7
is a waste treatment flow chart for cotton finishing wastes.
In-Plant Control - Practices to reduce the quantity and
strength of textile wastes include good housekeeping, closer
process control, process chemical substitution, and recovery.
Strict housekeeping procedures to minimize spills and wastes
will reduce the load by only 5-10%, or more at some locations.
8-6-13
-------
TABLE 8-6-1
TEXTILE INDUSTRY
J
RAW WASTEWATER CHARACTERISTICS
00
1
01
1
M
*>.
Parameter (mg/l)
BOD
TSS
COD
TDS
Alkalinity
pH
Oil
Sulfide
Chrome
Color
Wool Wool
Scouring Finishing
A B
1000-8000* 100-150
14-000-10,000 25- 80
3000-30,000*
1+000-15,000*
100-1900*
12*
1000-6000*
.1-1.0
High
Dry
Processing
C
65-1*00
1-1*00
1*55-1000*
130-1600*
30-2000*
0-11*
Woven Fabric
Finishing
D
30-1800*
1- 800
300-2500*
200-3700*
100-2100*
High
.1-8
3-28*
High
Knit Fabric
Finishing
E
60- 750*
30- 550
550-2000*
600-3500*
o- 500
High
50
5*
High
Carpet Mills
F
1*0-500
50-120
300-2500*
150-3000*
90-300
Neutral
12
.05-. 67
High
Stock & Yarn
Dying & Finishing
G
150- 600*
10- 50
360-11*00*
1000-2000*
100- 280
.6-2.1*
.1-12*
Note:
Data obtained from EPA files
*See Appendix 5 for parameters which may be inhibitory to biological systems.
-------
TABLE 8-6-2
TEXTILE ESDUSTRY
RAW WASTEWATER CHARACTERISTICS BASED ON PRODUCTION
Parameter
1
Water Use gal/lb
2
BOD kg/kkg
Wool
Scouring
A
3.4
Wool
Finishing
B
12.5
Dry
Processing
C
0.9
Woven Fabric
Finishing
D
13-5
20-140
Knit Fabric
Finishing
E
19.0
16-50
Carpet
Mills
F
6
Stock & Yarn
Dying & Finishing
a
21.5
15-48
00
I
Note:
Gallons of water used/pound of production
3
Kilograms of BOD/1000 kilograms of product manufactured
-------
KtPLANT
METHODS OF
DEDUCING
tOLLUTION
Replacement
of slashing
si/es with
low-pollution
compounds
Anacrohic
digestion
Seeding plus
aeration
Replacement
of soap by
synthetic
detergents
in washing
operations
SUBSEQUENT
TREATMENT
Segregation
of wastes
lo he
dumped or
burned
Sludge handling
Drying ptin incineration and/or landfill
Digestion plus incineration and/or land fill
Vacuum lilt rat ion
Lagooning
FIGURE 8-6-7
COTTON TEXTILE FINISHING WASTE TREATMENT CHART
8-6-16
-------
Closer control in the amount of chemicals used, as well as reduc-
tion in water usage may reduce pollution loads up to 30%. About
80% of all the water usage in textile wet processing is used
for scouring. Water usage can be improved by utilizing the so-
called "double-laced" box washers or in some cases by introduc-
ing counter-current washing flow schemes.
Chemical substitution is an important consideration in reduc-
tion of pollution. In some cases, it may be possible to sub-
stitute water with solvents such as perchloroethylene and tri-
chloroethylene for conventional aqueous scouring practices.
Solvent scouring and finishing of knit fabrics is being practiced
increasingly. The use of solvents minimizes liquid effluent
wastes but it also requires strict air pollution control meth-
ods.
Recovery is an important consideration in any waste treatment
plant. Caustic soda, steam and soaps can be recycled. Saleable
glucose may be recovered from starch, and lanolin from wool
grease. Suint can be recovered and sold to detergent manu-
facturers. Recovered fat might be rendered or used as a fuel
source.
Polyvinyl alcohol (PVA) size wastes are being economically
recovered in some plants so size wastes are expected to soon
disappear.
The use of pressure dyeing vats in place of atmospheric units
permits reduction in the amount of dye carriers required,
thereby reducing the BOD and heavy metal concentration.
Treatment Technology - Generally both physical-chemical and
biological methods are the treatment methods used by the
textile industry. Alum, ferrous sulfate, ferric sulfate, or
ferric chloride are used as coagulants, in conjunction with
lime or sulfuric acid for pH control. Calcium chloride has
also been found effective in coagulating wool scouring (A)
wastes. Biological treatment methods which are used in the
textile industry include activated sludge, trickling filter,
anaerobic processes, aerated lagoons and rotating biological
contractors.
One synthetic dying/finishing mill reports an 80% BOD removal
efficiency and a 38% COD removal efficiency with an aerated
lagoon treatment system. The two completemy mixed deep
lagoons produce an effluent of constant and predictable quality,
which is discharged to the municipal treatment syste. The
long detention time of about 17 days allows equalization and
treatment in the same unit process. Equalization storage of
24 hours allows the municipal plant operator the flexibility
8-6-17
-------
of choice in industrial effluent receipt. Capital construction
costs and operating expense are reported to be less than other
processes of comparable capacity.
In another study in a cotton finishing plant, washing and
rinsing wastes were segregated from concentrated dyeing and
finishing baths, and the more dilute wastewater for in-plant
reuse. By treatment of this wastewater in aerated lagoons,
and by neutralization, flocculation, filtration and adsorption,
a colorless turbidity-free effluent is obtained meeting qual-
ity requirements for in-plant reuse. To avoid excessive
salinity build-ups, part of the effluent has to be withdrawn
from the recycle system, but 70% of the effluent can be
recycled. The estimated cost of treatment is comparable to
that of fresh water supply. Table 8-6-3 contains removal
efficiencies achieved by various wastewater treatment prac-
tices for this industry.
8-6-18
-------
TABLE 8-6-3
TEXTILE INDUSTRY WASTEWATER TREATMENT PRACTICES
Removal Efficiencies (%)
Pollutant and Method
BOD
1. Chemical Coagulation
2. Activated Sludge
3. Trickling Filtration
4. Lagoons
5. Sedimentation
6. Oxidation Pond
Grease
1. Grease Recovery:
Acid cracking
Centrifuge
Evaporization
2. Sedimentation
3. Flotation
4. Lime + Cacl2 Coagulation
Suspended Solids
1. Grease Recovery
2. Sedimentation
3. Flotation
4. Chemical Coagulation
5. Activated Sludge
6. Trickling Filter
7. Lagoons
Color
1. Filtration + Carbon Adsorption
Wool Scouring
& Finishing
A + B
20
85
80
0
30
40
24
80
95
0
50
50
80
90
90
30
- 80
- 90
- 85
- 85
- 50
- 50
- 45
95
- 90
- 98
97
- 50
- 65
- 65
- 95
- 95
- 95
- 70
Finishing
D, E. G
25
70
40
50
5
30
30
85
80
50
60
95
85
95
15
80
15 - 60
90
95
90
95
98 - 100
8-6-19
-------
CEMENT
1. industry Description
The cement industry produces various types of Portland cement
for the construction industry. The raw materials for the pro-
duction of cement include lime, silica, alumina, and iron.
These materials, in chosen proportions, are ground, blended
and heated in a kiln. Establishments engaged in cement manufactur-
ing are included in Standard Industrial Classification(SIC) 3241.
2. Industrial Categorization
Although cement manufacturing does not generate a process waste-
water stream, it does generate kiln dust, cooling water, and
wastewater from clean up operations. It is the dust handling
process that is the source of significant wastewater loadings.
Consequently this industry is subcategorized along dust handling
lines.
Subcategory Designation
Nonleaching (A)
Leaching (B)
Material Storage Runoff (C)
3. Process Description
Cement is manufactured by a continuous process, normally
interrupted only to reline the kilns. There are three major
steps in the production process:
1. Grinding and blending of raw materials
2. Clinker production
3. Finish grinding
There are two (2) types of processes in the manufacture of
cement "wet" and "dry". In the wet process the raw materials
are ground together with water, fed to the kiln in a slurry
and the water is evaporated. In the dry process, the raw
materials are dried before grinding and are ground dry and fed
to the kiln in a dry state.
The clinker is the fused product from the kiln which is then
ground to make cement. No process wastewaters are generated.
A process flow diagram is in Figure 8-7-1.
All cement plants collect large amounts of dust from the
kiln. The high velocity gases flowing through the kiln carry
large quantities of this dust which are then removed by col-
lectors including cyclones, electrostatic precipitatars,
8-7-1
-------
Wet Process
Raw Materials
Crushing
Dry Process
Proportioning
and Mixing of
Raw Materials
in Slurrv Tanks;
'
r
Grinding
I
«3-
Homogenizing
and Blending
<
^»
a Water
Water
Proportioning
and Mixing of
Raw Materials
\
i
Grinding
1
Homogenizing
and Blending
Evaporation
t
Kiln
tOJ
,
y {
IM
In
Clinker Cooler
I
Finish
Grinding and
Gypsum
_ Addition
Cement Cooler
Storage
Bagging
Shipping
Clinkerj
Stpraae 1
Figure a-7-1 Flow Sheet for the Manufacture of
Portland Cement
8-7-2
-------
bag filters and wet scrubbers. This dust is either recycled
to the kiln or wasted. Some dusts contain an excessive
alkali content and must be leached before reuse(B). If
the kiln dust is not reused, it is disposed of by dry
piling (A). Figure 8-7-2 is, a flow diagram for Kiln Dust
Collection and Handling for both leaching and nonleaching
unit operations.
Nonleaching Plants (A) - Those manufacturing plants which
dispose of kiln dusts in a manner in which there is no water
contamination are included in this subcategory. Dry piling
does produce runoff, however, which is discussed under the
Materials Storage Subcategory (C).
Le'aching Plants (B) - Those operations in which the kiln dust
comes into direct contact with water are included in this
subcategory. The three leaching operations which generate
high wastewater loads include:
1. Leaching to remove soluble alkalies.
2. Wet disposal of dust.
3. Wet scrubbers for air pollution control.
(1) Leaching - The most significant of these operations is the
leaching (removal) of soluble alkalies from the collected dust
so that the dust may be returned to the kiln as recovered raw
material. In all cases the overflow (leachate) from this opera-
tion is discharged, sometimes without treatment. The con-
stituents include high pH, alkalinity, suspended solids,
dissolved solids, potassium, and sulfate.
(2) Wet Disposal - The second most common operation is the wet
disposal of dust. In this operation a slurry is also made of
the collected kiln dust and fed to a pond, where the solids
settle out. The settled solids are not recovered for return
to the kiln, and the overflow (leachate) may be discharged.
The constituents of this discharge are essentially the same
as those from the leaching operation.
(3) We t _.Scr ubbera - The use of wet scrubbers for air pollution
control constitutes the third example of water in direct con-
tact with the kiln dust. Wet scrubbers collect kiln dust from
effluent gases. Discharges contain the same contaminants as
those from leaching.
Materials Storage Runoff (C) - Runoff from kiln dust piles,
coal and raw materials piles may become contaminated if not
properly contained or treated. Some runoff may result from
routine clean-ups of accumulated dust or spraying of roads.
4. Wastewater Characterization - Tables1.8--7-1 and 8-7-2 contain
wastewater characteristics based on concentrations and production
for the cement industry.
8-7-3
-------
1 1
Electrostatic -
Precipitator
i
DU£
1
Return Pil<
to Kiln or
Kiln Dust
1
, r '
t
:yclone Bag House Wet Scrubber
1 i
1
st Bin
,
i
2, Bury, Mixed with Make-
Haul Water to * up
Form Slurry Water
Overflow Recycled
I
i »
SettlJ
Pone
^
Ivapornti on «]
^g overflow L*^g Un<
^ £\X±
(Thickener) to
v t>« ni
Neutralization
ierflow
turned
Kiln
.scharge
Discharge
Figure 8-7-2 Kiln Dust Collection and Handling
8-7-4
-------
TABLE 8-7-1
CEMENT MANUFACTURING
RAW WASTEWATER CHARACTERISTICS
Parameters
Flow (gpd)
Flow Type
BOD (mg/1)
TSS (rag/1)
COD (mg/1)
PH
Alkalinity (mg/1)
Total Solids (mg/1)
Chromium (mg/1)
Lead (mg/1)
Aluminum (mg/1)
Iron (mg/1)
Potassium (mg/1)
Nonleaching
A
500M-7MM
C
0
0
0
High
30
100
0
0
3
50 *
25
Leaching
B
5MM-75MM
C
0
30
1
High
45
225
3
35 *
20
150*
100
NOTE:
C Continuous
M Thousand
MM Million
*Usually present only if oyster shells are utilized in the
manufacturing process.
8-7-5
-------
TABLE 8-7-2
CEMENT MANUFACTURING
WASTEWATER CHARACTERISTICS BASED UPON PRODUCTION
Parameters
Flow (1/kkg)
Flow Type
BOD (kg/kkg)
TSS (kg/kkg)
COD (kg/kkg)
Lead (kg/kkg)
Aluminum (kg/
Iron (kg/kkg)
Nonleaching
1 A
r) 2M-3M
C
r) o
r) o
r) o
(kg/kkg) .09
s (kg/kkg) -3
:g/kkg) o
;g) o
:g/kkg) .01
:g) -16
kg/kkg) .08
Leaching
B
2.2M-30M
C
0
.9
.03
1.4
7.5
.08
1
.64
4.8
3.3
NOTE:
1 kgAkg kilogram pollutant/1000 kg product manufactured
M Thousand
MM Million
C Continuous
8-7-6
-------
5. Control and Treatment Technology
In-Plant Control Measures - With the exception of leaching
operations cement plants can achieve virtually complete reuse
of wastewater. Control technology for leaching operations
consists of segregation of leaching streams and conservation
of water to minimize the volume of water requiring treatment.
Temperature reduction of cooling waters has been accomplished
in cooling towers, spray ponds, and storage ponds.
Precautions to enclose the dust disposal area with dikes to
contain runoff will prevent runoff from kiln dust piles.
Spraying the dust pile with latex and coal pile with tar
can minimize water contamination.
Treatment Technology - Current technology can adequately con-
trol pH, alkalinity and suspended solids, but not dissolved
solids from leaching plants.
Neutralization of the leachate water by the addition of mineral
acids such as sulfuric acid has the following effects: it
lowers pH to any desired level; it eliminates alkalinity; it
dissolves some particulate matter such as lime. However, it
adds to the total dissolved solids.
Carbonation of the leachate with stack gas lowers the pH,
reduces the hardness, and the dissolved solids.
Several processes that might be employed to reduce dissolved
solids in leaching plants include evaporation, precipitation,
ion exchange, reverse osmosis,electrodialysis, and combinations
of these. Some of these processes have technical limitations;i.e.
ion exchange generates large amounts of waste material and the
dissolved solids content of the leachate is too high for reverse
osmosis to be practical.
Evaporation of the leachate could potentially eliminate the
effluent. Although solar evaporation has low operating costs,
it is applicable only in arid climates where a large amount of
land is available. Evaporation by submerged combustion or
heat exchangers involves considerable cost. Waste heat from
the kiln might be employed for evaporation.
Electrodialysis, a technology to concentrate leachate appears
promising. It produces a concentrated brine that can be
evaporated and a stream suitable for recycling to the leaching
system.
The retention of runoff from materials storage piles may be
achieved by dikes or ditches with direct runoff into a retention
pond where solids can settle. The effluent may be neutralized
and treated before discharge.
8-7-7
-------
FEEDLOTS
1. General industry Description
Animal production has evolved to the point where animals are
raised on large, highly efficient industrial "feedlots", where
animals, kept in high densities, are fed rations that will
provide the fastest weight gains.
A feedlot is defines as follows:
A. A high concentration of animals held in a small area for
periods of time in conjunction with one of the following
purposes:
a. Production of meat
b. Production of milk
c. Production of eggs
d. Production of breeding stock
e. Stabling of horses
B. Transportation of feeds to the animals for consumption.
C. By virtue of the confinement of animals or poultry, the land
or area will neither sustain vegetation nor be available for
crop or forage production.
Animal species produced in feedlots include cattle (beef and
dairy), swine, chickens, turkeys, ducks, sheep and horses.
This industry includes Standard Industrial Classifications (SIC)
0211, 0213, 0214, 0251, 0252, 0253, 0259, and 0272.
2. Industrial categorization
The feedlot industry is divided into the following subcategories;
Subcategory Designation
All subcategories except ducks A
Ducks B
3. Process Description
Cattle, swine, chickens, turkeys, ducks, sheep and horses are
produced on open or housed feedlots.
8-8-1
-------
Open Lot
An open lot is one in which the animals are either exposed to
the outside environment or in which a relatively small portion
of the feedlot offers some protection. The limited protection
afforded may be in the form of a windbreak, shed type building
with a roof and one to three sides enclosed, roof only, or some
type of latticework shade.
The floor of an open feedlot may be dirt with a flat or slightly
inclined surface. Figure 8-8-1 contains a sketch of an open lot.
Housed Lot
A housed feedlot is a building in which animals are kept under a
roof at all times. Buildings may have sides which are either
entirely open or completely enclosed. The floors can be of
solid dirt or concrete construction, or may have slotted floors.
Solid floor facilities utilize bedding material to absorb the
excreted wastes. Slatted floors use a shallow pit beneath the
floor for daily waste removal, or they may use deep pits for
waste storage. Figure 8-8-1 contains a sketch of a housed lot.
Dairy cattle are milked twice daily and require milking facilities
including transfer, storage and cooling equipment. Wastes can
be collected and 'field spread. Wastewater discharges may be
generated from milking center washups, and runoff from precipi-
tation on exposed contaminated surfaces.
Ducks are raised in wet and dry lots. A wet lot is one in which
the ducks have full access to swimming water for improvement in
the quality of feathers.
4. Wastewater Characterization
Feedlot wastes are generated from:
a. Bedding or litter (if used) and animal hair or
feathers
b. Water and milking center wastes
c. Spilled feed
d. Undigested or partially digested food or feed additives
8-8-2
-------
OF A CHMACTtmSTIC Of EH «[tf FfEW-OT fttRIH
CLOSED WT FEEDLOT
Figure 8-8-1
FEEDLOIS
8-8-3
-------
e. Digestive juices
f. Biological products of metabolism
g. Micro-organisms from the digestive tract
h. Cells and cell debris from the digestive tract wall
i. Residual soil and sand
Wastewater constituents are similar to domestic wastes and
contain BOD, COD, fecal coliforms, suspended solids, phosphorus,
ammonia and dissolved solids. Refer to Tables 8-8-1 and 8-8-2
for wastewater characterization of feedlots.
5. Control and Treatment Technology
In-Plant Control
Some of the in-plant controls that can be practiced by this
industry are as follows:
a. Compost and sell wastes as a product
b. Dehydration and sell or use as a feed
c. Conversion to oil
d. Runoff control
Treatment Technology
The following are some end of pipe treatment systems available
to this industry:
a. Land disposal
b. Oxidation ditches
c. Activated sludge
d. Incineration
e. Aerated Lagoons
f. Evaporation
g. Trickling Filters
The high concentration of solids present in animal waste can
vary all the way from semi-solid wastes containing 50% moisture
scraped from floors to the liquid wastes resulting from runoff
8-8-4
-------
TABLE 8-8-1
RAW WASTEWATER CHARACTERISTICS
FEZDLOT INDUSTRY
CO
I
00
I
en
WASTE PARAMETER (mg/l)
Flow Type
BOD
TSS
COD
pH
Total Nitrogen
Ammonia Nitrogen
Total Phosphorous
Total Potassium
Magnesium
Ash
Beef Cattle
Open Lot Dairy Cattle Swine Swine
Runoff Milk Wastes Manure Runoff
B B
1,700* 4,000*
35,000 2,400
4,000* No Data
7.6 8
200 450
70 130
90 60
400
110
4,000
C
2.5M-20,000*
9,000
6M*- 40M*
8.5
3,000
900- 3M*
400
600
Trace
5M-12M
B
100
260
300
7-8
20
10
5
10
2
2
Sheep and
Lambs
Manure
C
7,000*
35M
100M*
7
800
300
400
2,000*
300
15M
Sheep and
Lambs
Runoff
B
3M*- 12M*
8,000
10M*- 80M*
7-8
1,000
100 - 2M*
80 - 750
700 - 2,000*
20
6M - 18M
Ducks
Wet Lot
C & B
500
4,000
7,500*
7-8
50
No Data
70
No Data
No Data
No Data
Note: *See Appendix 5 for parameters which may be inhibitory to biological systems.
Some Subcategories have been grouped together.
No data are available for Turkey Runoff.
The remaining Subcategories produce only Dry Waste.
M - Thousand
MM - Million
B - Batch
C - Continuous
-------
TABLE 8-8-2
WASTE, CHARACTERIZATION-FEEDLOT INDUSTRY
Units Based on Production
WASTE PARAMETER
SUBCATEGORY
Flow
BCD
758
oo COD
1
°" PH
Total Nitrogen
Aononia Nitrogen
Total Phosphorous
Total Potassium
Magnesium
A»h
Beef Cattle
Manure
Ibs/head/day
48
1
-
3.5
7.3
0.27
0.08
0.07
0.2
0.02
2
Beef Cattle
Runoff
Ib/head/inch runoff
1,200
2
7.6
4
7.6
0.2
0.07
0.1
0.02
0.1
4
Dairy Cattle
Manure
Ibs/head/day
50-630
1-2
>.16
>6
5
0.2 - 0.4
0.2 - 0.3
>0.04
>0.2
>0.04
>1
Dairy Cattle
Milk Wastes
Ibs/head/day
30
1.2
0.08
No Data
8
0.04
0.005
0.002
No Data
No Data
No Data
Swine
Manure
Ibs/head/day
5-110
0.14
0.2
0.2
8.5
0.02
0.02
0.012
0.02
Trace
0.1
Swine
Runoff
Iba/head/inch runoff
900
0.5
1.2
1.3
7-8
0.1
0.04
0.02
0.02
Trace
0.3
Note: Some Subcategorlea have been grouped together.
-------
WASTE PARAMETER
TABLE 3-8-2 (Continued)
WASTE CHARACTERIZATION-FEEDLOT INDUSTRY
Units Based on Production
SUBCATEGORY
Chickens, Broilers Sheep and Lambs Sheep and Lambs
Layers, Breeders-Manure Manure Runoff
00
00
r
-j
Flow
BOO
TSS
COD
pH
Total Nitrogen
Ammonia Nitrogen
Total Phosphorous
Total Potassium
Magnesium
Ash
Ibs/lb/day
0.06
0.005
No Data
0.02
No Data
0.01
No Data
0.01
0.01
0.0003
No Data
Ibs/head/day
30
0.2
1
3
7
0.03
0.01
0.01
0.3
0.01
0.5
Ibs/head/inch runoff
160
0.5
0.7
2
7-8
0.2
0.02
0.02
1
0.02
1
Turkeys Turkeys
Manure Runoff
Ibs/head/day
l.S No Data
0.9
No Data
0.3
6.7
0.02
0.01
0.02
0.006
0.006
0.9
Ducks Pucks
Manure *«. U't
Ibs/head/day
No 1,000
Flow
0.06
0.2
0.3
7-8
0.006
No Data
0.02
No Data
No Data
No Data
Horse
Mnnuro
1 bs /head/day
80
0.8
No Data
4
7
0.6
0.2
0.1
0.6
0.8
10
Note: Some Subcategories have been grouped together.
-------
containing 2% solids. Animal waste, because of its high solids
concentration, if added in significant quantities to a municipal
system which operates with waste flows containing about 0.1%
solids, will exceed the design capability of the primary treat-
ment systems unless special provisions are made.
Because large solids concentrations may be present, secondary
treatment systems such as trickling filters could become clogged
and not capable of functioning while activated sludge systems
would probably operate with impaired performance. A judgement
should be made on an individual basis as to the amount of animal
waste which should be allowed to enter a particular treatment
system. Consideration should be given to the specific solids
type and concentration in the animal waste, the present municipal
waste load, and the treatment system and component capacity avail-
able to insure that a proper degree of dilution is maintained and
the system's operational capacity is not exceeded.
8-8-8
-------
METAL FINISHING
AND ELECTROPLATING
1. General Industry Description
The metal finishing industry utilizes chemical and electro-
chemical operations to effect an improvement in the surface
and structural properties of metals and other materials.
These operations include: coatings on surfaces by electro-
deposition; electroless plating; anodizing; chemical conversion
techniques such as phosphating, chromating and immersion
plating; and special contours or finishes obtained by electro-
chemical processes such as chemical milling and etching.
Wastewater from metal finishing processes comes from rinses
following cleaning, pickling, plating and etching operations,
and the waste streams contain concentrations of the basis
material being finished as well as the components in the
processing solutions. Occasional dumps of contaminated baths
are also a waste source. Contaminants include metal cations
(copper, nickel, chromium, zinc, lead, tin, cadmium, gold,
silver, platinum metals, etc.) and their associated anions,
such as phosphates, chlorides and cyanide.
Establishments engaged in this industry are covered by
Standard Industrial Classification (SIC) 3471.
2. Industrial Categorization
This industry has been divided into two major categories,
and a total of six subcategories as follows:
Major Category Subcategory Designation
Electroplating Common Metals (copper, nickel,
chromium, zinc, tin, lead,
aluminum, etc.) A
Precious Metals (silver, gold,
platinum, rhodium, iridium,
and ruthenium) B
Specialty Metals (beryllium,
magnesium, calcium, tellurium,
rhenium, cobalt, and mercury) C
Metal Finishing Anodizing D
Coatings E
Chemical Etching and Milling F
8-9-1
-------
3. Process Description
Electroplating (A) (B) (C)
The electroplating process includes pretreatment steps such as
cleaning, electroplating, rinsing, and drying. The cleaning
operation consists of two or more steps that are required for
removing grease, oil, soil, and oxide films from the basis metal
surface in order to insure good electroplating adhesion. In the
electroplating process, a solution containing metal ions is
reduced or plated onto a cathode surface, which is the material
being plated. The metal ions in solution are replenished by the
dissolution of metal from bars, wire or baskets that are used
as the plating material and act as the anode. Metal ions can
also be replaced by adding metal salts directly into the plat-
ing solution. In this case an inert material must be selected
for the anode. Hundreds of different electroplating solutions
have been adopted commercially. However, only two or three
types are utilized widely for a single metal or alloy.
Parts can either be barrel plated or rack plated. Barrel
plating, used for small parts, consists of placing the parts
in a rotating barrel, and allowing the parts to tumble
freely. Rack plating consists of attaching the parts to a
frame which dips the parts into the solution, and also carries
the parts from one tank, or operation, to another. After the
parts have been plated they are rinsed in order to remove the
plating solution, and then dried. Rinsewaters are a major
source of wastewater. Figure 8-9-1 is a flow diagram typical
of the electroplating industry.
Cleaning involves the removal of oil, grease, and dirt from
the surface of the basis material. Cleaning, or degreasing,
may be accomplished in one of several ways: alkaline clean-
ing, electrolytic (anodic and cathodic) cleaning, diphase
cleaning, emulsion cleaning, soaking, solvent cleaning, and
ultrasonic cleaning.
Alkaline cleaners most widely used in preparing the basis
material are composed of one or more of the following chem-
icals: sodium hydroxide, sodium carbonate, sodium metasilicate,
sodium phosphate, sodium silicate, sodium tetraphosphate, and
a wetting agent. Combinations and concentrations of these
chemicals vary depending on the basis material and the type
of soil being cleaned. Wastes contain the cleaning solution
plus the dirt removed from the basis material.
8-9-2
-------
Work flow
(Neutralize and
precipitate
Oxidize
cyanide
Precipitate
copper
Sludge
Precipitate
nickel and copper
Reduce
chromium
Precipitate
chromium
Treated water <
SCHEMATIC FLOW CHART FOR WA1LH FLOW IN CHROMIUM
PLATING ZINC DIE CASTINGS. DECORATIVE
Figure 8-9-1
Electroplating
8-9-3
-------
In the electrolytic cleaning procedure the basis metal acts
as either the cathode or the anode and a low voltage current
is passed through an alkaline cleaning solution. The genera-
tion of gases (hydrogen and oxygen) cause increased agitation
enhancing dirt removal.
Diphase cleaning takes place in a solution containing two
layers or phases, one being a water soluble and the other a
water insoluble solvent. This type of cleaning is useful
when both organic and inorganic compounds are required for
cleaning. This operation is also known as solvent cleaning.
Emulsion cleaning uses water, organic solvents and emulsifying
agents.
Ultrasonic cleaning utilizes ultrasonic energy to agitate the
cleaning solution. This is a more expensive operation, but
saves time and labor.
During the production of metals, oxides build up on the sur-
face during such operations as heat treating and welding.
Also rust may have built up if the part is not used immedi-
ately. Acid pickling is used to remove these oxide films
and involves the dissolution of oxide scale in the acid.
Acid solutions are made up from one or more of the following
acids: sulfuric, phosphoric, fluoboric, chromic and nitric
acids. The pickling solution needs to be replaced periodi-
cally, and the spent acid is discharged as waste and contains
the acids and metals removed by the acids.
Following preparation, the metal is plated by the electroplating
or electroless methods. Plating baths contain a wide variety
of chemicals and additives, which may end up in the wastewater.
Electroplating solutions are reused for long periods of time and
are infrequently dumped. Therefore, the principal source of
waste is the rinse water used to remove the solution that remains
on the work surfaces (dragout). When the plating solutions are
wasted, they are usually bled slowly into the rinse water waste
stream. On the other hand, electroless plating baths may
periodically be discharged since the life of these baths are
shorter than for electroplating baths.
Copper is electroplated from four (4) types of baths: alkaline
cyanide, acid sulfate,pyrophosphate, and fluoborate, which are
prepared with a corresponding copper salt. Copper is extensively
electroplated as a base for further electroplating with nickel
and chromium.
Nickel is electroplated from Watts (sulfate-chloride-boric
acid), sulfamate, chloride, and fluoborate baths. Each
type of solution is prepared with the corresponding nickel
salt, a buffer and a small concentration of wetting agent.
8-9-4
-------
In many operations nickel plating is followed by chrome plat-
ing.
All chromium plating solutions contain chromic acid and a
small amount of sulfuric acid or a mixture of sulfuric acid
and fluosilicate or fluoride ions. Spray carried from the
solution by the gases generated at electrode surfaces is a
significant waste source. Air scrubbers can recover and re-
cycle it to the chromium bath.
Zinc is electroplated in cyanide solutions containing sodium
cyanide, zinc oxide or cyanide and sodium hydrozide; non-
cyanide alkaline solutions prepared with a variety of chelating
agents; acid or neutral chloride baths. Zinc waste is gen-
erated during continuous or batch filtration. Gas evolution
at electrode surfaces create aerosol particles which can be
removed by water scrubbing.
Silver and gold are plated from cyanide baths. Since both
metals are costly, much effort is made to recover them from
waste streams, so that the major pollutant load is cyanide.
Platinum, rhodium, palladium, iridium, and ruthenium are
used much less frequently than those previously mentioned.
In addition, very little, if any, waste is expected from
these operations. This is due to the fact that very small
volumes of baths are used, and extensive recovery techniques
are employed.
Specialty metals operations exist in only a few places in
the country, and are associated with large industrial com-
plexes, such as the aerospace industry. Therefore, a spe-
cialty metal plating shop cannot be identified as such, but
will be part of an overall process in other industries.
As much as 90% of the water usage in this industry is from
rinsing. The rinse water is used to remove the films of
processing solutions (plating solutions) from the surface
of the plated materials. In performing this task, the water
becomes contaminated with the constituents of the operating
solutions, and is discharged as a p'ollutant bearing stream.
Many plants use more rinse water than is required, and in
these cases water volume should be reduced.
Electroless plating is used when a thicker coat of metal is
required than can be accomplished by electrolytic plating
described above. Electroless is also used to coat complex
shaped items and to plate plastic parts. Nickel and copper
are the primary coating materials used in this process.
8-9-5
-------
Electroless plating occurs by catalysis rather than by inter-
change of ions as in electroplating, and electricity is not
used, as the name implies. Some materials are conditioned to
attract the coating materials, while others accept the coating
without conditioning.
There are a variety of preparation steps prior to electroless
plating. Parts are cleaned in the same manner as in electro-
plating (e.g. alkaline cleaning). Plastics are prepared by
roughening the surface by abrasion or by chemical means with
chromic acid. Plastic parts are conditioned by placing them
in a solution of stannous chloride. Iron, nickel, and cobalt
do not require conditioning steps prior to plating, but do
require cleaning; while aluminum and magnesium do require con-
ditioning steps in addition to cleaning.
The electroless baths used for coating nickel are acidic, and
contain nickel chloride or sulfate, sodium hypophosphate as
the reducing agent, and an organic acid. The organic acid
acts as both a buffer to help maintain the pH of the bath and
as a complexing agent for the nickel ions in solution. Copper
baths contain copper sulfate with either Rochelle salt (sodium
potassium tartrate) or EDTA (ethylenediaminetetraacetic acid,
sodium salt) as the complexing agent and formaldehyde as the
reducing agent. Unlike conventional electroplating solutions
which are commonly used for many years and are seldom discarded,
electroless plating baths have finite life and must be period-
ically discarded as waste. The baths are usually trickled
slowly into a rinse tank, which acts as a diluting step.
Coating operations can be a complete operation performed by
a metal finishing shop, and are then classified as "coatings"
plants (subcategory-E). However chemical conversion coating
operations can also be a post treatment operation in an electro-
plating plant, and would then fall under subcategory-A.
Refer to the process description given for subcategory (E) for
more information on this process.
Metal coloring consists of converting the metal surface to its
oxide form, or to an insoluble metal compound by immersing the
metal in an aqueous solution. These finishes are used on
copper, steel, zinc, and cadmium. Because the coatings are
extremely thin and delicate, and lack resistance to handling
and the atmosphere, they are given a coat of clear lacquer to
protect the colored metal surface. Organic dyes can also be
added to the coloring solution to impart a particular color
desired. Wastewater production is similar to electroplating
processes.
8-9-6
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Anodizing (D)
The anodizing process is an electrolytic oxidation process
by which the surface of the metal is converted to an in-
soluble oxide having desirable properties. Anodizing pro-
vides corrosion protection, decorative surfaces, a base for
painting and other coating operations, and special electrical
and engineering properties. Aluminum, zinc and magnesium are
the metals which are anodized, but aluminum is the major ma-
terial treated by this process.
The metal is prepared by soak cleaning with an alkaline cleaner
or a phosphoric acid solution. Cleaning etches the metal
slightly, which insures an active surface for anodizing. The
metal is then immersed in sulfuric and chromic acid solutions
followed by rinsing. Wastes are similar to those generated
by electroplating rinse water.
Anodizing posttreatment for aluminum consists of improving
the corrosion resistance of the coatings by immersing the
material in deionized water at a temperature of 99°C (210°F).
Sometimes organic dye is added to impart coloring. Waste-
waters from this operation should not be high in pollutant
loading unless organic dyes are used.
Chemical Conversion Coatings (E)
Protective coatings or films are produced on metal surfaces
by chromating, phosphating or immersion plating.
Chromating - A portion of the base metal is converted to one
of the components of the film by reaction with aqueous solutions
containing hexavalent chromium and other active organic or
inorganic compounds. Chromate coatings are most frequently
applied to the following metals: zinc, cadmium, aluminum,
magnesium, copper, brass, bronze, and silver. The coatings
can be applied by either electrochemical action or chemical
immersion. These coatings are used for protective or decora-
tive purposes or as a base for paint when the original material
does not have good adhering properties for paint. Chromate
conversion coatings are frequently applied to zinc or cadmium
plated parts immediately following electrodeposition. The
wastewaters are similar to those for electroplating processes.
Phosphating - Phosphating is the treatment of iron, steel,
zinc plated steel, and other metals by immersion in a dilute
solution of phosphoric acid plus other reagents to produce an
integral conversion coating on the surface. The process is
similar to chromating, and the wastes are similar to electro-
plating waste streams.
8-9-7
-------
Immersion Plating - This is a chemical plating process in
which a thin metal deposit is obtained by chemical displace-
ment of the basis material. In immersion plating a metal
will displace from solution any other metal that is below it
in the electromotive series of elements. The less active
metal will be deposited from solution while the more active
metal (the item being plated) will be dissolved. This pro-
cess is used to insure corrosion protection or as a prepara-
tion for painting or rubber bonding, and is mostly used for
the following combinations:
1. Tin on brass, copper, steel or aluminum.
2. Copper on steel.
3. Gold on copper or brass.
4. Nickel on steel.
Preparation for immersion plating consists of an alkaline
cleaning step and a pickling step, which produce wastewaters
similar to the pretreatment steps described earlier.
Chemical Milling and Etching (F)
Chemical milling is the process of shaping, machining, fabri-
cating or blanking metal parts to specific design configurations
and tolerances by controlled dissolution with chemical reagents
or etchants. Chemical etching is the process of removing re-
latively small amounts of metal from the surface to improve
the surface condition of the basis metal or to produce a
pattern such as printed circuit boards. Grease and dirt are
removed from metal surfaces by vapor degreasing and alkaline
cleaning, and scale and films are then removed by pickling.
Areas where no metal removal is desired are masked off by
dipping, spraying or roll or flow-coating. Mask patterns can
also be applied by the use of photosensitive resists, which
are used for printed circuits. After the masking step, the
part is given an acid dip to activate the surface for etching.
Etching solutions include ferric chloride, nitric acid, chromic
acid, sodium and ammonium persulfate, and cupric chloride.
Wastewaters contain the etching solutions plus concentrations
of the particular metal being etched.
4. Wastewater Characterization
Table 8-9-1 shows wastewater characteristics for the industry.
Sources of wastewater include:
1. Rinsing to remove films of processing solution
from the surface of the work pieces at the site
of each operation.
8-9-8
-------
Notes:
TABLE 8-9-1
METAL FINISHING INDUSTRY
Raw Wastewater Characteristics'
Parameter
Flow, gpd
Flow Type
TSS
TDS
PH
Zinc
Iron
Cadmium
Nickel
Copper
Lead
Sodium
Aluminum
Chromium, Hexavalent
Chromium, Total
Cyanide
Fluoride
Phosphate
1 Data obtained from EPA files
Concentration, mg/1
10 M - 500 M
C or I
5-20
500-1 M
2*-13*
10*-100*
10-1000
10*-100*
10*-100*
10*-100*
10*-100*
500
2
0
8*-40
3*
4*
10*-50
20*-100*
5-500*
5-500
2 Anodizing wastes can have aluminum concentrations between
50-100 mg/1
3 Range shown is after dilution with other streams. Without
dilution, 150-400 mg/1
4 Range shown is after dilution with other streams. Without
dilution, 200-500 mg/1
M = 1,000
C - Continuous
I - Intermittent
* See Appendix 5 for parameters which may be inhibitory
to biological systems.
8-9-9
-------
2. Spills and leaks.
3. Air pollution scrubbers.
4. Dumping of plating solutions.
5. Washing of equipment.
6. Discharges of cooling water.
5. Control and Treatment Technology
In-Plant Control - The control of electroplating wastewaters
includes process modifications, material substitutions, good
housekeeping and water conservation techniques including:
a. Elimination of copper plating by increasing the
thickness of nickel.
b. Substituion of dilute electroplating solutions
for concentrated baths where possible.
c. Substituion of noncyanide solutions in place of
cyanide solutions, where possible.
d. Substitution of trivalent chromium baths for
hexavalent chromium baths.
e. Improvement in the racking procedure to improve
drainage from surfaces over the process tank
prior to rinsing.
f. Increasing drainage time over process tank.
g. Reducing viscosity of the process solution.
h. Addition of wetting agent to process solution
to reduce surface tension.
i. Installation of air or ultrasonic agitation.
j. Installation of counterflow rinses whereby water
exiting the last tank in the rinsing operation
becomes the feed water for the preceding rinse.
This practice can reduce water consumption by as
much as 90%.
k. Minimizing water use.
Treatment Technology - The first step in treating metal
finishing wastewaters is to separate the cyanide bearing waste
streams from the chromium bearing waste streams. Then, waste-
water containing only metals should be segregated as a third
waste stream. Cyanide is generally destroyed by oxidation
under alkaline conditions with chlorine. The reactions take
place in baffled tanks with adequate detention times for the
destruction to proceed to completion. Since hexavalent
chromium is soluble, it must be reduced to the trivalent
form before it can be precipitated. This is usually accom-
plished under acidic conditions with sulfur dioxide, sodium
bisulfite or ferrous sulfate. The chemical reactions are
8-9-10
-------
also generally accomplished in baffled tanks. After the
cyanide is destroyed and the chromium is reduced, these
streams can then be combined with the metal bearing streams
for precipitation and removal of the metals.
Table 8-9-3 contains wastewater treatment practices for this
industry.
8-9-11
-------
TABLE £-9-3
METAL FINISHING INDUSTRY
WASTEWATER TREATMENT PRACTICES
Pollutant and Effluent Levels
Method Attainable, Mg/L
Heavy Metals
Precipitation, Floculation
and Clarification
Iron 1.0
Zinc 0.5
Copper 0.5
Nickel 0.5
Lead 0.5
Tin 1.0
Cadmium 0.3
Cyanide
Cyanide destroyed to carbon dioxide
and nitrogen .05-0.5
Chrome
Hexavalent chrome reduction
to trivalent chrome, plus
precipitation and clarification 0.5
8-9-12
-------
ORGANIC CHEMICALS
1. General Industry Description
Organic chemicals are the raw materials for a multitude of
products the public uses daily, including plastics, synthetic
fibers, synthetic rubber, dyes, solvents,food additives,
Pharmaceuticals, lubricants, detergents, and cosmetics. Syn-
thetic organic chemicals are derived as a result of the physical
and chemical conversion operations from naturally occurring raw
materials such as petroleum, natural gas, and coal.
Approximately 50% of the plants in this industry discharge to
municipal treatment works. Wastewaters from this industry
contain BOD, COD, TSS, phenols, sulfates, oil and grease, and
some metals.
Establishments engaged in this industry are covered by Standard
Industrial classification (SIC) 286.
2. Industrial Categorization
This industry has been divided into the following subcategories;
each includes a series of products as follows:
Subcategory
Nonaqueous Processes
Processes with Process
Water Contact as Steam
Diluent or Absorbent
Products
Benzene-Toluene-Xylene
(BTX)
Cyclohexane
Vinyl Chloride
Cumene
P-Xylene
Acetone
Butadiene
Ethyl Benzene
Ethylene and Propylene
Ethylene Dichloride
Ethylene Oxide
FormaIdehyde
Methanol
Methyl Amines
Vinyl Acetate
Vinyl Chloride
AcetaIdehyde
Acetylene
Butadiene
Styrene
Designation
B
8-10-1
-------
Subcategory
Diluent or Absorbent
(Continued)
Aqueous Liquid Phase
Reaction Systems
Products
Chlorobenzene
Chloromethanes
Chlorotoluene
Diphenylamine
Perchloroethylene
Phthalic anhydride
Hexamethylened iamine
Methyl ethyl ketone
Tricresyl phosphate
Adiponitrile
Benzoic acid and
benzaldehyde
Methyl Chloride
Maleic anhydride
Acetic acid
Acrylic acid
Coal tar
Ethylene glycol
Terephthalic acid
AcetaIdehyde
Caprolactam
Coal tar
Oxo chemicals
Phenol and acetone
Aniline
Bisphenol A
Dimethyl terephthalate
Acrylates
p-Cresol
Methyl methacrylate
Tetraethyl lead
Ethyl acetate
Propyl acetate
Propylene glycol
Cyclohexanone oxime
Isopropanol
Oxalic acid
Formic acid
Calcium stearatic
Hexamethylenetetramine
Hydrazine solutions
.Isobutylene
Designation
8-10-2
-------
Subcategory
Aqueous Liquid Phase
Reaction Systems
(Continued
Products
Designation
Batch and Semi-Continuous
Processes
Sec-bentyl alcohol
AeryIonitrile
Synthetic cresol
Caprolactam
p-Aminophenol
Propylene Oxide
Pentaerythritol
Saccharin
o-Nitroaniline
p-N itroan i1ine
Pentachlorophenol
Fatty acids
Fatty acid derivatives
lonone and methylionone
Methyl salicylate
Miscellaneous batch
chemicals
Citronellol and Geraniol
Plasticizers
Dyes and dye intermediates
Pigments, toners
Pigments, lakes
Citric acid
Napthtenic acid
Sodium glutamate
Tannic acid
Vanillin
3. Process Description
General
The process area of an organic manufacturing plant is referred
to as the "Battery Limit", while the remainder of the plant
is called the "Off-Sites".The off-sites can be broken down into
their components; the storage and handling facilities, the
utilities, and the services. This is illustrated in Figure
8-10-1.
8-10-3
-------
FIGURE 8-10-1
PLOT PLAN FOR CHEMICAL PLANT
ILLUSTRATING FOUR-AREA LAYOUT
I
UTILITIES
STEAM
GAS
AIR
REFRIGERATION
ELECTRIC WATER
1
J
1 ' '
00
I
( T*NK ) C FARM
STORAGE AND HANDLING
PROCESS AREA
OO
BATTERY LIMIT
STORAGE
O O O O
'IT
:f
4 I I I I I I I I I I II I I III I II I I II I
RAILWAYS
ft
SERVICES
J
SHOPS
OFFICE
ROADS
Organic Chemicals
-------
The storage facilities associated with any chemical plant depend
upon the physical state (i.e. solid, liquid, or gas) of the
feedstocks and products. Storage equipment includes cone-roof
tanks for liquids, cylindrical or spherical tanks for gases,
and concrete pads or silos for solids. Wastewater emanating
from this part of the plant normally results from storm run-off,
tank washing, accidental spills, and aqueous bottoms periodically
drawn from storage tanks. These wastes are generally, small in
volume, but since they do come into contact with process
chemicals, these chemicals will appear in the waste stream.
Utility functions such as the supply of steam and cooling water
generally are set up to service several processes. Noncontact
steam, generated in the boiler house, is circulated through a
closed loop whereby varying quantities are made available to
the different processes.
The uses for steam are as follows:
a. For noncontact process heating.
b. For power generation such as steam driven turbines, com-
pressors, and pumps.
c. For use as a diluent, stripping medium, or source of vacuum.
Th"is use of steam will become contaminated and will need treat-
ment.
Wastes from non-contact use of steam come from purges of the
system, boiler blowdowns, and water treatment systems which are
used to make good quality water for the steam generation system.
Non-contact cooling water is also supplied to the processes.
Once through cooling systems constitute an uncontaminated
waste stream, while cooling tower blowdowns from closed cooling
systems contain water treatment chemicals.
The service area of the plant contains the buildings, shops,
and laboratories, in which the personnel work. Waste streams
are generated from laundry facilities, sanitary facilities, and
wastes from laboratory and shop operations.
In regard to the "battery limits", most plants manufacture many
different products. Each process is itself a series of unit
operations which causes chemical and physical changes in the
feedstock or products. In the commercial synthesis of a single
product from a single feedstock, there generally are sections
of the process associated with: the preparation of the feed-
stock; the chemical reaction; the separation of reaction products;
and the final purification of the desired product. Each unit
8-10-5
-------
operation may have drastically different water usages associated
with it. The type and quantity of contact waste water are
therefore directly related to the nature of the various processes,
This in turn implies that the types and quantities of waste
water generated by each plant's total production mix are unique.
The production from a given process module is related to the
design capacities of the individual unit operations within it.
In many cases, the unit operations are arranged as a single
train in series. In other cases, some unit operations such as
the reaction are carried in several small reactors operating
in parallel.
The flow of material between unit operations within a process
may be either a continuous stream or through a series of batch
transfers.
There are two major types of manufacturing process within the
industry:
a. Continous processing operations.
b. Batch processing operations.
Facilities utilizing continuous processes manufacture products
in much greater volumes than do batch operations. Although
the initial manufacture of many chemicals was first done by
batch processing, changes to continuous processing were made
when markets were enlarged to meet increasing and changing
demands.
Batch processing is still extensively practiced, particularly
when the production is small or where safety demands that
small quantities be handled at one time. Furthermore, batch
operations are more easily controlled when varying reaction
rates and rapid temperature changes are key considerations.
The feed preparation section may contain equipment such as
furnaces where the liquid feed is vaporized or heated to
reaction temperature, or large steam driven compressors for
compressing gaseous feed to the reaction pressure. It may
contain distillation columns to separate undesired feed impuri-
ties which might damage the catalyst in the reactor or cause
subsequent unwanted side reactions. Impurities may also be
removed by preliminary chemical conversion (such as the hydro-
genation of diolefins) or by physical means such as silica
gel driers to remove trace amounts of moisture.
8-10-6
-------
The reaction section of the process module is where the prin-
cipal chemical conversions are accomplished. The reactor may
be as simple as a hollow tube used for noncatalytic vapor-
phase reactions. However, most industrial reactions are
catalytic and generally require more complex reactor designs.
The specific reactor design is usually governed by the required
physical state of the reactants and catalyst.
Catalysts are of two types: heterogeneous and homogeneous.
Heterogeneous catalysts are usually solids which may be composed
of chemically inactive material such as finely ground aluminum
or contain metals such as cobalt, platinum, iron, or manganese
which are impregnated on a solid support. In heterogeneous
reaction systems, the reactants are usually in the vapor phase.
The conversion proceeds in three steps: adsorption of the
reactants upon the surface of the catalyst; chemical reactions
on the surface of the catalyst; and desorption of the products
from the catalyst surface.
Homogeneous catalysts exist in the same physical state as the
reactants and products. This may require the use of an aqueous
or non-aqueous solvent to provide a reaction media. Typical
homogeneous catalysts include strong acids, bases, and metallic
salts which may be in the form of a solution or a slurry. It
should be noted that the recovery, reconcentration, or regene-
ration of these catalysts may require the use of processing
equipment much more elaborate than the reactor itself.
The recovery of reaction products may involve a wide variety
of processing operations. If the reactor effluent is a vapor,
it may be necessary to condense and quench the products in a
direct contact medium such as water. In many instances, the
desired products are absorbed in water and are subsequently
stripped from the water by heating. Liquid reactor effluents
are separated from solvents (and catalysts) by distillation.
In almost all cases, the conversion of feed is not complete, so
that continuous separation and recycle of unconverted feed to
the reactor is necessary.
Final purification of the products is normally required both
when they are to be sold and when they are used as intermediates.
Most specifications restrict contaminant levels to the range of
parts per million. Because of this, additional operations such
as distillation, extraction, crystallization, etc. are necessary.
The product is pumped from the battery limits to tanks in the
storage area.
8-10-7
-------
In large-scale continuous processes, all of the subsections
of the probess module are operated with the use of automated
controls; in some cases, complete automation or computer
control is utilized.
When chemical manufacturing is on a small scale, or when it is
not adaptable to continuous procedures, a batch sequence is
frequently used. This requires more supervision on the part of
operators and engineers, because the conditions and procedures
usually change from the start to the finish. Batch operations
with small production and variable products also transfer
equipment from the making of one chemical to that of another
based on the same type of chemical conversion. Hundreds of
specific products may be manufactured within the same building.
This type of processing requires the cleanout of reactors and
other equipment after each batch. Purity specifications may
also require extensive purging of the associated piping. Rapid
changes in temperature during the batch sequence may also
require the direct addition of ice or quench water as opposed
to slower non-contact cooling through a jacket or coils.
Process waters from batch or continuous processes within the
battery limits include not only water produced or required by
the chemical reactions but also any water which comes in contact
with chemicals within each of the process modules. Although
the flows associated with these sources are generally much
smaller than those from non-contact sources, the organic
pollution load carried by these streams is greater by many
orders of magnitude.
Process water is defined as all water which comes in contact
with chemicals within the process and includes:
1. Water required or produced (in stoichiometric quantities)
in the chemical reaction.
2. Water used as a solvent or as an aqueous medium for the
reactions.
3. Water which enters the process with any of the reactants
or which is used as a diluent (including steam).
4. Water associated with the catalyst system, either during
the reaction or during catalyst regeneration.
8-10-8
-------
5. Water used as an absorbent or as a scrubbing medium for
separating certain chemicals from the reaction mixture.
6. Water introduced as steam to strip certain chemicals
from the reaction mixture.
7. Water used to wash, remove, or separate chemicals from
the reaction mixture.
8. Water associated with mechanical devices such as steam-
jet ejectors for drawing a vacuum on the process.
9. Water used as a quench or direct contact coolant such as
in a barometric condenser.
10. Water used to clean or purge equipment used in batch type
operations.
11. Runoff or wash water associated with battery limits
process areas.
The type and quantity of process water usage are related to
the specific unit operations and chemical conversions within
a process. The term "unit operations" is defined to mean
specific physical separations such as distillation, solvent
extraction, crystallization, adsorption, etc. The term
"chemical conversion" is defined to mean specific reactions
such as oxidation, halogenation, neutralization, etc.
Description of Subcategories
Four process subcategories have been established. Subcate-
gories A, B, and c relate to continuous processes, while
Subcategory D relates to batch processes. The subcategories
are described as follows:
Nonaqueous Processes (A)
In this subcategory there is minimal contact between water and
reactants or products within the process. Water is not required
as a reactant or diluent and is not formed as a reaction
product. The only water usage stems from periodic washes of
working fluids or catalyst hydration. Raw waste loads should
approach zero with the only variations caused by spills or
process upsets.
8-10-9
-------
Processes With Process Water Contact as Steam Diluent or
Absorbent (B)
Process water usage is in the form of dilution steam, a direct
contact quench, or as an absorbent for reactor effluent gases.
Reactions are all vapor-phase and are carried out over solid
catalysts. Most processes have an absorber coupled with steam
stripping of chemicals for purification and recycle. Steam
is also used for de-coking of catalyst.
Continuous Liquid-Phase Reaction Systems (C)
Liquid-phase reactions where the catalyst is in an aqueous
medium such as dissolved or emulsified mineral salt, or acid-
caustic solution. Continuous regeneration of catalyst system
requires extensive water usage. Substantial removal of spent
inorganic salt by-products may also be required. Working
aqueous catalyst solution is normally corrosive. Additional
water may be required in final purification or neutralization
of products.
Batch and Semicontinuous Processes (D)
Processes are carried out in reaction kettles equipped with
agitators, scrapers, reflux condensers, etc. depending on the
nature of the operation. Many reactions are liquid-phase with
aqueous catalyst systems. Reactants and products are trans-
ferred from one piece of equipment to another by gravity flow,
pumping, or pressurization with air or inert gas. Much of the
material handling is manual with limited use of automatic
process control. Filter presses and centrifuges are commonly
used to separate solid products from liquid. Where drying is
required, air or vacuum ovens are used. Cleaning of noncon-
tinuous production equipment constitutes a major source of
waste water. Waste loads from product separation and purifi-
cation will be at least ten times those from continuous processes,
4. Wastewater Characterization
Table 8-10-1 contains raw wastewater characteristics for the
industry. The raw waste loads shown in the table for subcate-
gories A, B, C are based on contact process water only. Non-
contact water is excluded for continuous processes since these
plants have been able to achieve segregation of non-contact
cooling water or steam. Subcategory D includes all water usage
associated with the process in that rapid cooling with direct
contact is required in the manufacture of dyes.
8-10-10
-------
TABLE 8-10-1
ORGANIC CHEMICALS INDUSTRY
00
I
(-<
O
I
RAW WASTEWATER CHARACTERISTICS
Subcategories
Non Aqueous
Processes-A
C
10-100
20-50M*
100-10M*
0-1
100-3M
0-15
.} 1-150
10-250*
Present
Processes with
Process water as
Steam Diluent or
Absorbent - B
C
100-500
10-2300
400-100M*
200-5M*
0-0.3
100-2M
0-20
1-50
2-200*
Present
Aqueous Liquid
Phase Reaction
Systems - C
C
10-4M
23-100M*
10M-50M*
0-1
3M-5M
0-6000
0-1000
0-1200*
Present
Batch and
Semi-continuous
Processes - D
B
20-4M
40-300M*
1M-10M*
0.02
0-150
5-1000
10-4000*
Present
Present
Waste Parameter
Flow Type
BOD (mg/1)
TSS .(mg/1)
TDS (mg/1)
COD (mg/1)
Cyanide (mg/1)
TOC (mg/1)
Phenol (mg/1)
Ammonia Nitrogen(mg/1)1-150
Oil (mg/1)
Metals
Color
Notes:
M = 1,000
* See Appendix 5 for parameters which may be inhibitory
to biological systems
B-Batch Process
C-Continuous Process
-------
5. Control and Treatment Technology
Jn-Plant Control
The following in-plant control measures are practiced in this
industry:
1. Substitution of surface heat exchangers for contact cooling
water used in barometric condensers.
2. Regeneration of contact process steam from contaminated
condensate.
3. Substitution of vacuum pumps for steam jet ejectors.
4. Recycle of scrubber water.
5. Recovery of insoluble hydrocarbons.
6. Solvent extraction for recovery of phenols.
Treatment Technology
Biological treatment is the major treatment technology used in
this industry. Both single stage and multiple stage plants
are used, especially when phenol removal is required. Filtra-
tion is also used as a polishing step after biological treatment.
Activated carbon is becoming more evident as an alternate treat-
ment scheme to biological treatment. Contact times of 22 - 660
minutes are required as opposed to 10-50 minutes for domestic
waste. Pretreatment for suspended solids and oil removal is
required to levels of at least 10 mg/1 TSS and 50 mg/1 of oil.
Equalization is also good practice before all forms of treatment
schemes. Table 8-10-2 gives removal efficiencies for the treat-
ment systems described above.
8-10-12
-------
TABLE 8-10-2
ORGANIC CHEMICALS INDUSTRY
WASTEWATER TREATMENT PRACTICES
Pollutant and Method Removal Efficiencies %
BOD
Biological Treatment 93
Filtration (percentage is between inlet
and outlet of filter) 17
Pretreatment plus activated carbon 90
COD
Single Stage Biological Treatment 69
Multiple Stage Biological Treatment 74
Filtration (percentage is between inlet
and outlet of filter) 20
Pretreatment plus activated carbon 69
TOC
Single Stage Biological Treatment 60
Multiple Stage Biological Treatment 79
Filtration (percentage is between inlet
and outlet of filter) 20
Pretreatment plus activated carbon 87
8-10-13
-------
INORGANIC CHEMICALS
1. General Industry Description
The Inorganic Chemical Manufacturing Industry produces a wide
range of chemicals that are fundamental to the U. S. dconomy.
The manufacturing plants tend to be large and produce multiple
products by application of basic, simple chemical reactions
and/or physical separation techniques from ores or natural
brines. Plants tend to be located near raw materials or
sources of needed chemicals.
The wastewaters from this industry are generally low in BOD,
and COD, but do contain dissolved solids, alkalinity, suspended
solids, and some metals. This industry includes Standard
Industrial Classifications(SIC) 2812 and 2819.
2. Industrial Categorization
The major inorganic products segment of this industry has been
divided into the following subcategories:
Subcategory Designation
Aluminum Chloride A
Aluminum Sulfate B
Calcium Carbide C
Calcium Chloride D
Calcium Oxide and Calcium Hydroxide E
Chlorine and Sodium or Potassium Hydroxide F
Mercury Cell Process F(a)
Diaphragm Cell Process F(b)
Hydrochloric Acid G
Hydrofluoric Acid H
Hydrogen Peroxide I
Oxidation of Alkyl Hydroanthroquinones I(a)
Electrolytic Process I (b)
Nitric Acid J
Potassium Metal K
Potassium Dichrornate L
Potassium Sulfate M
Sodium Bicarbonate N
Sodium Carbonate O
8-11-1
-------
Subcategory
Designation
Sodium Chloride
Solar Evaporation
Solution Brine-Mining
Sodium Bichromate and Sodium Sulfate
Sodium Metal
Sodium Silicate
Sodium Sulfite
Sulfuric Acid
Titanium Dioxide
Chlorine Process
Sulfate Process
P
P(a)
P(b)
Q
R
S
T
U
V
V(a)
V(b)
The significant inorganic products segment of this industry
has been tentatively divided into the following subcategories
1. aluminum fluoride
2. ammonium chloride
3. ammonium hydroxide
4. barium carbonate
5. borax
6. boric acid
7. bromine
8. calcium hydroxide
10. carbon dioxide
11. carbon monoxide
12. chrome green*
13. chrome yellow and
orange*
14. chromic acid
15. chromic oxide*
16. copper sulfate
17. cuprous oxide
18. ferric chloride
19. ferrous sulfate
20. fluorine
21. hydrogen
22. hydrogen cyanide
23. iodine
24. iron blues*
25. lead oxide
26. lithium carbonate
27. manganese sulfate
28. molybdate chrome orange*
29. nickel sulfate
30. nitric acid (strong)
32. oxygen
33. potassium chloride
34. potassium iodide
35. potassium permanganate
36. silver nitrate
37. sidium bisulfite
38. sodium fluoride
39. sodium hydrosulfide
40. sodium hydrosulfite
41. sodium silicofluoride
42. sodium thiosulfate
43. stannic oxide
44. sulfur dioxide
45. zinc oxide
46. zinc sulfate
47- zinc yellow*
*Combined as chrome pigments and iron blues in one production
subcategory.
8-11-2
-------
3. Process Description
Aluminum Chloride (A)
Aluminum chloride is made by the reaction of chlorine with
molten aluminum. The aluminum chloride vapor is collected
on air cooled condensers. There are two sources of waste-
water: uncondensed aluminum chloride and chlorine tail gases,
and unreacted aluminum metal. if the tail gases are scrubbed,
the aluminum chloride recovered, and the scrubbing solution
returned to the system, no wastewater is produced in this
process.
Aluminum Sulfate (B)
Aluminum sulfate is prepared by reaction in a digester of
bauxite ore or aluminum clays with sulfuric acid. Figure 8-11-1
is a flow diagram for this process. The resulting product
solution, containing muds and other insolubles from the ore, is
then fed to a settling tank, wherein the insolubles are removed
by settling and filtration. The aluminum sulfate may be sold
as a solution or evaporated to yield a solid product.
Raw wastes from this process include insoluble muds from the
digester, settling tank and filtration unit, as well as wash-
waters from vessel cleanouts. If spills and washwater are
collected, and wastewater is treated and recycled, there is
no discharge.
Calcium Carbide (C)
Calcium carbide is manufactured by the thermal reaction of
calcium oxide and coke. Calcium oxide and dried coke are
reacted in a furnace, and the product is then cooled, crushed,
screened, packaged and shipped. The only wastes from the
process are airborne dusts from the furnace, coke dryer and
screening bag filters.
Calcium Chloride (D)
Calcium chloride is produced by extraction from natural brines.
The salts are solution mined, and the resulting brine solution
is concentrated. Chemicals are added to remove other materials
such as sodium chloride, potassium, and magnesium salts. The
8-11-3
-------
SULFURIC
ACID
BAUXITE
ORE
WASHOUT <
WASTES
(MUDS, Al (SOA,
H2S04) 2 4*
WASTE
(MUDS)
WASTE
(MUDS)
I i
DIGESTER
SETTLING
TANK
V
FILTRATION
EVAPORATION
I I
SOLID
ALUMINUM
SULFATE
PRODUCT
STEAM
STORAGE
LIQUID
ALUMINUM
SULFATE
PRODUCT
FIGURE 8-11-1
STANDARD PROCESS DIAGRAM FOR
ALUMINUM SULFATE MANUFACTURE
-------
remaining calcium chloride solution is evaporated to dryness,
packaged, and sold. Raw wastes, consisting of weak brine
solutions, come from blowdowns and from the partial evaporation
steps used.
Calcium Oxide and Calcium Hydroxide (E)
Calcium oxide is manufactured by thermal decomposition of lime-
stone in a kiln. The limestone is first crushed, then added
to the kiln, where it is calcined to effect decomposition.
The product is then removed from the kilns, marketed as calcium
oxide, or slaked by reaction with water to produce calcium
hydroxide. The only waste stream from this process is from
the use of wet scrubbers for cleaning the plant gas effluent.
Chlorine and Sodium or Potassium Hydroxide (F)
Mercury Cell Process - F(a) Caustic and chlorine are produced
from either sodium or potassium chloride raw materials depending
on end product desired. Figure 8-11-2 shows a flow diagram for
this process. The raw material is purified by dissolving in
water followed by barium carbonate treatment to precipitate
magnesium and calcium salts. The brine is then fed to the
mercury cell, where the chlorine is liberated at one electrode
and sodium-mercury amalgum is formed at the other. The chlorine
is cooled, dried in a suIfuric acid stream, purified to remove
chlorinated organics, compressed, and sold. The mercury-sodium
amalgum is decomposed by water treatment in a "denuder" to
form sodium (or potassium) hydroxide and hydrogen. These
products are treated and sold, and the mercury recovered. The
sulfuric acid stream is recycled.
Wastewaters consist of purification muds (calcium carbonate,
magnesium hydroxide and barium sulfate) from brine purification,
some spent brine solutions and condensates from chlorine and
hydrogen compressions. Wastes also contain mercury.
Diaphragm Cell Process - F(b) The products and wastes of the
diaphragm cell process are similar to those from the mercury
cell process except that the cell is manufactured differently
and mercury is not usually present in the effluent.
Hydrochloric Acid (G)
Hydrochloric acid is manufactured principally by two processes:
(1) as a by-product of organic chlorinations; and (2) by direct
8-11-5
-------
SOLUT
MININ
Roa
AND
DISSOL
cc
o o It
PJO
0 «J X
z *. o x
\1/ W W
run i. ,M BRINE
UN Naci ^ PURIFICATION "} EVAPORATI01
b " FILTRATION "
4^
WASTE
C NaCI
VE
WASTE
SOLAI
AND
DISSOL'
' NaCI
/E
V
WASTE
X = PROPRIETARY INGREDIENTS
(POLYELECTROLYTES,
FLOCCULANTS, ETC.)
*> CONDENSATE H,
8
2
g
M ff *
% -i 3*
OX 0
z O a
II JH.
w _^/ \|/ w \/
-^ «.,.».. Hg CELL
^ PURIFICATION HO tLtUIRUU
i "
V SPENT SALT 50«J
WASTE " I NaO
(PURGE)
v
CAUSTIC
FILTRATION
t
H9 COOL
^ AND
' TREAT
V °*
= WASTE !^
?
-ia? COOLING
l*" f.
j =? AND ^ '
J DRYING
«>
<, WASTE
rt TO PROCESS
W" "1 "t
PURIFICATION _L CI2 TO
COMPRESSION LIQUFICATION
Jrc.
WASTE
FIGURE 8 -11-2
STANDARD
CHLORINE-CAUSTIC FLOW DIAGRAM MERCURY CELL PROCESS (p-a)
INORGANIC CHEMICALS MANUFACTURING
-------
reaction of chlorine with hydrogen. Only production by direct
reaction of chlorine is considered herein. In this process,
hydrogen and chlorine are reacted in a vertical burner. The
hydrogen chloride formed is condensed in an absorber from which
it flows to a storage unit for collection and sale.
Waterborne wastes are only produced during start-ups. At other
times, no wastewater flow is produced.
Hydrofluoric Acid (H)
Hydrofluoric acid is manufactured by reaction of sulfuric acid
with fluorspar ore (mainly calcium fluoride). The reaction
mixture is heated and the hydrofluoric acid leaves the furnace
as a gas, which is then cooled, condensed and sent to a purifi-
cation unit. There the crude hydrofluoric acid is redistilled
and either absorbed in water to yield aqueous hydrofluoric acid
or compressed and bottled for sale as anhydrous hydrofluoric
acid. Wastewaters are generated from furnace cleanups. These
washwaters are composed of salt-containing slurry water and
fluoride-containing air scrubbers.
Hydrogen Peroxide (I)
Hydrogen peroxide is manufactured by three different processes:
(1) An electrolytic process; (2) An organic process involving
the oxidation and reduction of anthraquinone; and (3) A by-
product of acetone manufacture from isopropyl alcohol. In this
study, only the first two processes are discussed.
Electrolytic Process I(a) In the organic process, anthraquinone
(or an alkylanthraquinone) in an organic solvent is cataly-
tically hydrogenated to yield a hydroanthraquinone. This
material is then oxidized with oxygen or air back to anthraquinone,
with hydrogen peroxide being produced as a by-product. The
peroxide is water-extracted from the reaction medium, and the
organic solvent and anthraquinone are recycled. The recovered
peroxide is then purified and shipped.
Electrolytic Process I(b) In the electrolytic process, a solution
of ammonium bisulfate is electrolyzed. Hydrogen is liberated'
at the cathodes of the cells used, and ammonium persulfate is
formed at the anode. The persulfate is then hydrolyzed to yield
ammonium bisulfate and hydrogen peroxide which is separated
8-11-7
-------
from the solution by fractionation. The ammonium bisulfate
solution is then recycled, and the peroxide is recovered for
sale. Raw wastes consist of ammonium bisulfate losses, ion
exchange losses, boiler blowdowns and some cyanide wastes
from the special batteries used in electrolysis.
Wastewaters contain alkalinity, dissolved solids, and some
metals (e.g. iron).
Nitric Acid (J)
Nitric acid is manufactured from ammonia by a catalytic oxi-
dation process. Ammonia is first catalytically oxidized to
nitric oxide, which is then further oxidized to nitrogen
dioxide. The nitrogen dioxide is then reacted with water under
pressure to yield nitric acid.
Wastewaters are produced only from cooling tower blowdown
which contain water treatment chemicals.
Potassium Metal (K)
For the commercial preparation of potassium metal (K) , potassium
chloride is melted in a gas-fired melt pot and fed to an
exchange column. The molten potassium chloride flows down over
steel Raschig rings in the packed column, where it is contacted
by ascending sodium vapors coming from a gas-fired reboiler. An
equilibrium is established between the two, yielding sodium
chloride and elemental potassium as the products. The sodium
chloride formed is continuously withdrawn at the base of the
apparatus and is normally sold. The column operating conditions
may be varied to yield either pure potassium metal as an over-
head product or to vaporize sodium along with the potassium to
produce sodium potassium (NaK) alloys of varying compositions.
Potassium metal of over 99.5 percent purity can be continuously
produced by this process.
No process water is used in this process and no wastewater is
produced.
Potassium Dichromate (L)
Potassium dichromate is prepared by reaction of potassium chloride
with sodiumidichromate. Potassium chloride is added to the
dichromate solution, which is then pH-adjusted, saturated,
8-11-8
-------
filtered and vacuum cooled to precipitate crystalline potassium
dichromate. The product is recovered by centrifugation, dried,
sized and packaged. The mother liquor from the product centri-
fuge is then concentrated to precipitate sodium chloride which
is removed as a solid waste from a salt centrifuge. The
process liquid is recycled back to the initial reaction tank.
Only solid wastes and cooling water are produced in this
process.
Potassium Sulfate (M)
The bulk of the potassium sulfate manufactured in the United
States is prepared by reaction of potassium chloride with
dissolved langbeinite ore (potassium sulfate-magnesium sulfate).
The langbeinite ore is mined and crushed and then dissolved in
water to which potassium chloride is added. Partial evaporation
of the solution produces selective precipitation of potassium
sulfate which is recovered by centrifugation or filtration from
the brine liquor, dried and sold. The remaining brine liquor
is either discharged to an evaporation pond, reused as process
water or evaporated to dryness to recover magnesium chloride.
The fate of the brine liquor is determined by the salability of
the magnesium chloride by-product (depending on ore quality) and
the cost of water to the plant.
The brine wastes that are produced contain primarily magnesium
chloride. Much of the water is recycled.
Sodium Bicarbonate (N)
Sodium bicarbonate is manufactured by the reaction of soda ash
(sodium carbonate) and carbon dioxide in solution. The product
bicarbonate is separated by thickening and centrifugation and
is then dried, purified and sold.
Wastewaters are produced from slurry thickener overflow which
contain sodium bicarbonate and from power generation boiler
foodwater purification.
Sodium Carbonate (O)
Soda ash (sodium carbonate) is produced by mining and by the
Solvay Process. In the Solvay Process sodium chloride brine
8-11-9
-------
is purified to remove calcium and magnesium compounds. It is
reacted with ammonia and carbon dioxide produced from lime-
stone calcination to yield crude sodium bicarbonate which is
recovered from the solutions by filtration. The bicarbonate
is calcined to yield soda ash. The spent ammonia solution is
reacted with slaked lime and distilled to recover ammonia
values for process recycle. The calcium chloride formed as
a by-product during the distillation is either discharged as
a waste or recovered by evaporation.
Wastewaters are high in dissolved and suspended solids.
Sodium Chloride (P)
Sodium chloride is produced by three methods:
1. Solar evaporation of seawater;
2. Solution mining of natural brines;
3. Conventional mining of rock salt. (Not discussed herel
Solar Evaporation Process P(a) In the solar evaporation
process, seawater is concentrated by evaporation in open ponds
to yield a saturated brine solution. After saturation is
reached, the brine is then fed to a crystallizer, wherein
sodium chloride precipitates, leaving behind a concentrated
brine solution (bittern) consisting of sodium, potassium and
magnesium salts. The precipitated sodium chloride is recovered
for sale and the brine is then further evaporated to recover
additional sodium chloride values and is then either stored,
discharged back to salt water or further worked to recover
potassium and magnesium salts.
Solution Brine-mining Process P(b) In the solution brine-
mining process, saturated brine for the production of evaporated
salt is usually obtained by pumping water into an underground
salt deposit and removing the saturated salt solution from an
adjacent interconnected well, or from the same well by means
of an annular pipe. Besides sodium chloride, the brine will
contain some calcium sulfate, calcium chloride, magnesium
chloride, and lesser amounts of other materials including iron
salts and sulfides.
The chemical treatment given to brines varies from plant to
plant depending on the impurities present. Typically, the
brine is first aerated to remove hydrogen sulfide and, in many
8-11-10
-------
cases, small amounts of chlorine are added to complete sulfide
removal and oxidize all iron salts present to the ferric state.
The brine is then pumped to settling tanks where it is treated
with soda ash and caustic soda to remove most of the calcium,
magnesium and iron present as insoluble salts. After clarifi-
cation to remove these insolubles, the brine is sent to multiple-
effect evaporators. As water is removed, salt crystals form
and are removed as a slurry. After screening to remove lumps,
the slurry is washed, filtered, dried and screened.
Wastewaters are produced from boiler blowdowns, evaporator
purges and cleanings, cooling waters and brine sludges.
Sodium Bichromate and Sodium Sulfate (Q)
Sodium dichromate is prepared by calcining a mixture of chrome
ore (FeO.Cr O ), soda ash and lime, followed by water leaching
and acidification of the soluble chromates. The insoluble
residue from the leaching operation is recycled to leach out
additional material.
During the first acidification step, the pH of the chromate
solution is adjusted to precipitate calcium salts. Further
acidification converts chromate to the dichromate and a sub-
sequent evaporation step crystallizes sodium sulfate (salt
cake) out of the liquor. The sulfate is then dried and sold.
The solutions remaining after sulfate removal are further
evaporated to recover sodium dichromate. Chromic acid is
produced from sodium dichromate by reaction with sulfuric acid.
Sodium bisulfate is a by-product.
Wastewaters are generated from spills and washdowns, and contain
hexavalent chromium. Boiler blowdown and water treatment
processes can constitute other waste streams, which contain
dissolved sulfates and chlorides.
Sodium Metal (R)
Sodium is manufactured by electrolysis of molten sodium
chloride in a Downs electrolytic cell. After salt purification
to remove calcium and magnesium salts and sulfates, the sodium
chloride is dried and fed to the cell, where calcium chloride
is added to give a low-melting CaCl -NaCl eutectic, which is
8-11-11
-------
then electrolyzed. Sodium is formed at one electrode, collected
as a liquid, filtered and sold. The chlorine liberated at
the other electrode is first dried with sulfuric acid and then
purified, compressed, liquified and sold.
Wastewaters are produced from cleaning the electrolytic cells,
cooling tower blowdowns, gas scrubbers, cooling waters,
runoff water, and contain mostly dissolved chlorides.
Sodium Silicate (S)
Sodium silicate is manufactured by the reaction of soda ash or
anhydrous sodium hydroxide with silica in a furnace, followed
by dissolution of the product in water under pressure to
prepare sodium silicate solutions. In some plants, the liquid
silicate solutions are then further reacted with sodium
hydroxide to manufacture metasilicates which are then isolated
by evaporation and sold.
Wastewaters contain sodium silicate and unreacted silica.
Sodium Sulfite (T)
Sodium sulfite is manufactured by reaction of sulfur dioxide
with soda ash. The crude sulfite formed in this reaction is
then purified, filtered to remove insolubles from the purifi-
cation step, crystallized, dried and shipped.
Wastewaters from the purification step contain sulfides, and
vessel cleanouts contain sulfite and sulfate.
Sulfuric Acid (U)
Sulfuric acid is manufactured primarily by the contact process
which involves catalytic oxidation of sulfur dioxide to sulfur
trioxide and reaction of the sulfur trioxide with water to
yield sulfuric acid. Within the contact process, there are
three types of plants: double absorption, single absorption
and spent acid.
In the double absorption contact process, sulfur is burned to
yield sulfur dioxide which is then passed through a catalytic
converter with air to produce sulfur trioxide. The sulfur
trioxide is then absorbed in 95-97 percent sulfuric acid.
The gases emerging from the absorber are fed to a second
8-11-12
-------
converter vto oxidize the remaining sulfur dioxide to sulfur
trioxide which is then absorbed in a second absorption tower.
The tail gases are vented to the atmosphere; tail gas scrubbers
are not required.
Process water is normally consumed or recycled. Cooling water
is the only discharge.
The single absorption process differs from that previously
described only in the arrangement of converters and absorbers.
The rest of the process is the same. For the single absorption
process, the sulfur dioxide is passed through one or more
converters and then into one or more absorbers prior to venting
to the atmosphere. This arrangement is less effective for both
conversion of sulfur dioxide to sulfur trioxide and for
absorption of the sulfur trioxide into the absorber sulfuric
acid. As a result, the tail gases may have to be scrubbed to
remove sulfur oxides, creating a waterborne waste not present
for double absorption plants.
Spent acid plants use spent sulfuric acid in place of, or in
addition to, sulfur as a raw material. While the acid production
parts of these plants are the same as those for single absorp-
tion, these plants are unique because of the spent acid
pyrolysis units used to convert the waste sulfuric acid raw
materials to a sulfur dioxide feed stream. Discussion of
wastes from spent acid plants is not included here.
Titanium Dioxide (V)
Titanium dioxide is the most widely used white pigment. It
is produced by two methods: the "sulfate" process and the
"chloride" process.
Chloride Process V(a) In the chloride process, shown in
Figure 8-11-3, titanium dioxide (TiO,,) ores are chlorinated
to produce titanium tetrachloride, iron chlorides and other
metal chlorides. Coke is included to promote the reaction.
The resulting titanium tetrachloride is oxidized to titanium
dioxide and chlorine which is recycled.
Impurities in the system, including the iron and other metal
chlorides, entrained coke and ore, carbon monoxide and
dioxide, and hydrogen chloride all have to be removed prior to
the oxidation reaction, creating a significant effluent waste
control problem. After chlorination, the products are cooled
8-11-13
-------
nnr - "Si
COKE ^
[ TO WAS
DRYER j
^
DRYER ) >
F«CIX,HCI,SOU
CHEMIC
TREAT
v
AIR, 02,N2, WATER
J/
1 o2
TO WASTE
DISPOSAL
A
T
WATER
TREATMENT AGEI
FINISHED Ti
STANDAR
HEATER J
V
t
Ul
OS
AL
MENT-
1DGE
CHLORI
S
\
riCI4, F8CI3, COKE, O^t, C02, N2, C02
t
COOLING TOWER |^ 1
\
ORE REC
\
LIQUIF/
> H
S x
g .J WATER
:i4 -" i- w
ACTION i.- ^ "scnunnrn 1
\1/ \/
TiCI4 UJ^.Ng.iA)
PURIFICATION
\
/
TiCI4 VAPORIZER
>
/
TiC14 HEATER
\/
MAKF IIP PllinniNF "*>
OXIDATION
REACTOR
\
^
f
RAPID COOLING
\
TI02,
f
CRUDE TiOj
COLLECTION
\
\
Ti02
t
:INER
f
YT >j TREAT
\
f
Clo, No
1
h»
>^
^
02< 1 MILLING I ^
c.2lN2
FIGURE ,3-11-3
D CHLORIDE PROCESS TITANIUM DIOXIDE
FLOW DIAGRAM
INORGANIC CHEMICALS INDUSTRY
8-11-14
-------
by centrifugation or filtration, and the gaseous titanium
tetrachloride is condensed. Noncondensable reaction gases
containing titanium tetrachloride, silicon tetrachloride and
hydrogen chloride are water scrubbed, then vented. A number
of techniques are used to further purify the tetrachloride,
removing traces of silicon, vanadium, magnesium, manganese,
aluminum and chromium. These techniques yield a pure titanium
tetrachloride and a wastewater.
After purification, the titanium tetrachloride is vaporized
and passed into a reactor with heated air or oxygen. The
solid titanium dioxide particles are mechanically separated
from the gas stream, calcined, ground, treated and packed.
Wastes contain metal salts, waste coke, hydrochloric acid,
titanium hydroxide, dissolved solids.
Sulfate Process V(b) In the sulfate process, titanium dioxide-
bearing ores are dissolved in sulfuric acid at high tempera-
tures to produce titanium sulfate as an intermediate product.
In some cases, small amounts of antimony trioxide are also
added. The acid solution is clarified, a portion of the iron
sulfates is removed by crystallization, and the titanium
sulfate is hydrolyzed to form a white, non-pigmentary hydrate.
The hydrate is calcined to form crystalline titanium dioxide,
which is milled, surface treated, and packaged for sale.
Process wastewaters are acidic and contain dissolved and sus-
pended solids and metal salts.
Significant Inorganic Products (1-47)
As shown in the subcategorization section of this report, the
significant inorganic products segment of this industry con-
sists of forty seven (47) product subcategories. Processes
consist of chemical reactions and/or physical separation
techniques from ores or natural brines. The processes and
water uses are similar to those described for the major
inorganic chemicals, and will not be discussed in detail here.
Wastes contain concentrations of the chemicals in the raw
materials, and also concentrations of the products produced.
Wastewaters are also generated by auxiliary systems, such as
boiler blowdowns, cooling water discharges, equipment cleanups,
and spills and leaks.
8-11-15
-------
4. Wastewater Characterization
Table 8-11-1 contains raw wastewater characteristics for the most sig-
nificant of the subcategories discussed.
5. Control and Treatment Technology
In-Plant Control - The following in-plant controls can reduce
wastewater effluent:
a) The use of gas scrubbing and the sale of scrubber wastes,
or chemical treatment of scrubber wastes can eliminate the
waste stream for Aluminum Chloride (A) and Calcium Oxide
and Calcium Hydroxide (E).
b. Recycle of process wastewaters are practiced for Aluminum
Sulfate (B) and Sodium Sulfite (S).
c. The substitution of dry bag collector systems for wet
scrubber systems have been effective for Calcium Carbide (C)
and Calcium Oxide and Calcium Hydroxide (E).
d. Separation of salts in the waste stream, followed by
recycle or sale of these salts is utilized for Calcium
Chloride (D).
e. The muds produced in Chlorine and Sodium or Potassium
Hydroxide (Fj can be clarified and disposed of in landfills.
The mercury from F(a) can be precipitated with sulfides.
Asbestos in the diaphragm cell process F(b) can be filtered or
clarified. Some salts can be recycled back into the process.
f. Neutralization followed by precipitation can reduce sulfate
and fluoride contents in Hydrofluoric Acid Production (H).
g. Clarification with skimming can reduce the organic solvents
and suspended solids in the Hydrogen Peroxide Organic Process
I (a). Scrap iron decomposes the Hydrogen Peroxide in the
waste stream. The Electrolytic Process I(b), produces a very
small process waste stream, and total evaporation has been
used to eliminate this stream.
h. Distillation of the brine waste to recover water from the
Potassium Sulfate (M) subcategory has been successful in
accomplishing a closed cycle plant.
8-11-16
-------
TABLE 8-11-1
INORGANIC CHEMICAL INDUSTRY
RAW WASTEWATER CHARACTERISTICS
Subcategory
A,B,C,E,G,
Parameter (mg/l) J,K,L,U
Flow (gpd) No
Process
Flow Type Waste
BOD (mg/l)
TSS
IDS
COD
00
tl PH
^ Color(APHA Units)
Alkalinity
Mercury
Calcium
Fluoride
Chromium(+6)
Nitrate
Sulfate
Sulfite
Notes: M - 1,000
D F(a)
8 MM
C
1
30 5-10
300
7-9 6.7-8.5
60-80
235
8-^5*
170-700
F(b) H I,P,S,R,V M N,0 Q T
No Only 17 M
Data Solid
Mud C
Wastes
0
22 M 17 M 200 170 M 2 M
18 M* k.SM* 76 M 5M-13M* 90 M
13 8 M*
If* 11* 10* 11*
300
600
650 1*5 M
13
1300*
9.8
3.9M
60 M
MM - 1,000,000
B - Batch
C - Continuous
* See Appendix 5 for parameters which may be inhibitory to biological systems.
-------
i. Clarification to settle suspended solids has been practiced
by Sodium Bicarbonate (N) and Sodium Carbonate (0) sub-
categories.
j. Return of the waste waters to the source of the brine
materials is usually practiced for Sodium Chloride (P).
k. Separation of the hexavalent chrome stream, chemical
reduction to trivalent chrome, followed by precipitation and
clarification is practiced for Sodium Dichromate and Sodium
Sulfate (Q) production.
1. Clarification of the mud bearing streams with land disposal
of the mud is practiced for Sodium Metal (R) production.
m. Conversion of Sulfite to Sulfate followed by recovery of
the sulfate can be accomplished for Sodium Sulfite Production (T)
n. Containment of spills and leaks followed by neutralization
or recycle is practiced for Sulfuric Acid Production (U). Con-
centration and recovery of the SO scrubber waste stream can
also be practiced.
o. Chemical precipitation followed by clarification and land
disposal-of sludges is practiced for Titanium Dioxide, Chlorine
Process U(a) and Sulfate Process U(b).
Treatment Technology - The type, degree and costs involved
depend upon specific circumstances unique for each chemical.
Various treatment techniques commonly used in the inorganic
chemicals manufacturing industry include settling ponds or
vessels, filtration, chemical treatment, centrifugation,
evaporation, drying and carbon adsorption.
A number of options for the final disposal of waterborne
wastes from inorganic chemical manufacturing are available,
depending upon quantity and characteristics of the waste
stream. They include discharge to surface water, land dis-
posal, and unlined or lined evaporation ponds.
8-11-18
-------
PLASTICS AND SYNTHETIC
MATERIALS
1. Industry Description
The plastics and synthetics industry is composed of three
segments: the manufacture of the raw material or "monomer",
the conversion of this monomer into a resin or plastic material,
and the conversion of the plastic resin, or polymer, into a
plastic item such as a toy, synthetic fiber, packaging film,
adhesive, paint, etc.
This description is concerned with the manufacture of the plastic
or synthetic resin and the manufacture of synthetic fibers, such
as nylon, rayon, cellulose film and others described in the sub-
categorization section of this industry.
Waste from this industry can be high in BOD, and COD and can
contain metals.
This industrial category includes Standard Industrial Classifications
(SIC) 2821, 2823, 2824 and 3079.
2. Industrial Categorization
The industry has been categorized according to waste charac-
teristics and subcategorized along product lines as follows:
Main Category I - Generates a low raw waste load (less than
10 units/1000 units of product produced); low BOD concentrations
attainable (less than 20 mg/1).
Main Category II - Generates a high waste load (greater than
10 units/1000 units of product); low BOD concentrations
attainable (less than 20 mg/1).
Main Category III - Generates a high waste load (greater than
10 units/1000 units of product); medium BOD concentrations
attainable (30-75 mg/1).
Main Category IV - Generates a high waste load (greater than
10 units/1000 units of product); high BOD concentrations
attainable (over 75 mg/1).
8-12-1
-------
Main
Category Subcategory Designation
I Polyvinyl Chloride A
I Polyvinyl Acetate B
I Polystyrene C
I Polypropylene D
I Polyethylene E
II Cellophane F
II Rayon G
II ABS/SAN (Aerylonitrile,butadiene,
styrene/styrene,acrylonitrile) H
III Polyester I
III Nylon 66 J
III Cellulose Acetate L
IV Acrylics M
I Ethylene-Vinyl Acetate N
I Polytetrafluoroethylene 0
I Polypropylene Fibers P
III Alkyds/Polyester Resins Q
III Cellulose Nitrate R
III Polyamides S
III Polyesters (thermoplastic) T
III Silicones U
III Epoxy Resin V
IV Phenolic Resin W
IV Urea & Melamine X
8-12-2
-------
3. Process Description
Polymerization is the formation of long chain molecules from
a single type molecule, or "monomer". For example:
Monomer A + monomer A fr -A-A-A-A-A-(polymer)
Copolymers are formed by combining two different monomers.
For example:
Monomer A + monomer B-nm>M*^ -A-B-A-B-A- (copolymer)
.Polymerization takes place in reactors which can be either a
ipatch or continuous process. Many reactions require a catalyst
in order for the reaction to occur.
Polyvinyl Chloride (A), Polyvinyl Acetate (B), Polystyrene (C)
ABS/SAN (H)
Polymers A, B, C and H can be manufactured by the Emulsion and
Suspension Polymerization process in which the monomer is
dispersed in an aqueous, continuous phase during the course
of the reaction. The batch cycle consists of the continuous
introduction of a water-monomer emulsion to a stirred, tempera-
ture controlled reactor ranging in size from 5,000-30,000
gallons. On completion of a batch, a short "soaking" time is
allowed for completion of reaction. Water is added to dilute
to the desired end composition, and the batch is screened and
stored.
In some cases, the water-polymer emulsions are marketed in this
latex form, thus no wastewater is generated. When the polymer
is isolated and sold a wastewater contaminated with polymer is
discharged. Monomers that are protected by an inhibitor are
subject to washing prior to polymerization. This contributes
to the wastewater load. Figure 8-12-1 contains a process flow
diagram for this process.
Atmospheric or Low-Pressure Mass Polymerization is a process
used to manufacture polymers A, Cr H,^as shown on Figure 8-12-1.
Reaction rate and final product obtained are dependent on tempera-
ture control as well as catalysts and modifiers used. The
catalyst and modifier remain in the product. Inhibitors are
usually added to the monomer for protection during storage. This is
removed by washing,thus generating a wastewater. During separation
of the unreacted monomer and contaminants from the product by
vacuum stripping, a waste stream containing these chemicals is
produced.
8-12-3
-------
EMULSION POLYMERIZATION (A, B, C, H)
MONOMER
INHIBITOR
WASIE
CONDENSER
WAFER
MASS POLYMERIZATION (A, C, H)
FIGURE 8-12-1
POLYMERINATION
8-12-4
-------
Polyethylene (E)
Ethylene gas is mixed with a very small quantity of catalyst
and raised to a high pressure in the High Pressure Mass
Polymerization process. At the appropriate pressure and
temperature, polymerization is carried out in jacketed (cooled)
tubular reactors. On completion of the reaction, the polymer
is flash cooled in drums containing water. The low density
polyethylene is then .formed into pellets and separated from
the water. The water is recycled, but is periodically purged
producing a waste stream.
Polyethylene (E) and copolymers can be manufactured by the
Solution Polymerization process, in which the polymer is dis-
solved in the reaction solvent as it is formed, and the catalyst
is present as a separate solid phase. The catalyst system is
activated chromium oxide deposited on a carrier such as alumina.
After reaction the catalyst and solvent are separated from the
polymer and then separated from each other.
The water used in the separation processes constitutes a waste
stream, which will contain quantities of catalyst, solvent and
polymer. A process flow diagram is shown in Figure 8-12-2.
Polyethylene (E), Polypropylene (D), and some copolymers can be
manufactured by the Ziegler Process. This process is similar
to the Solution Polymerization Process except that the polymer
precipitates as it is formed rather than remaining in solution.
Products of this process include: high density-polyethylene,
Polypropylene, polybutene, copolymers. Wastewaters contain
solvent (aqueous alcohols).
The Particle Form Process is an improvement on the two previously
described, using a continuous system with the product drawn off
continuously from a "loop" reactor«, Wastes contain polymer
fines and solvents (aqueous alcohols).
Cellophane and Rayon (F)(GL
Cellophane and Rayon are both regenerated cellulose products
that are produced by treating wood pulp and cotton 1inters (raw
cellulose) by the Viscose process. Here raw cellulesic polymer
is treated to form a solution of viscose, processed and trans-
formed back into cellulosic plastics of desired shapes.
8-12-5
-------
fOLTOUFIN PRODUCTION - SOLUTION MLOCCSS ,(£),
TPA
tTMTLENE
6LTCOL
H,0
6LYCO
PRlMART
ESTERIFtER
:
PRESSURE
RECTiriCATION
L CtrCOL WASTE STREAM
SEPARATION
SWCOL r .Srw?M RECTrCLE
RECrCLE ^* RECOVERr P- *
(STEAM EJECTOR! (S
j^C ,T~ POLrMERlZAflON | POLYMERIZATION
L_ 1_ (OPTIONAL?)
'
POl
M
" ri Yrni " 6LYCOL 10
CLYCOL RECYCLE
RECOVERY "
TEAM EJECTORI
" ""(CASTING) "CHIP'S*
V "f
^
\
.TMER POLYMER
ELT MELT
V
POLYESTER
TO BALER STAPlf
CUTTER
DRYER
j
*£L
H^
CRIMPER TOW
DRAWING
POLYESTER FIBER AND RESIN PRODUCTION(I)
FIGURE 8-12-2
POLYMERIZATION
PLASTIC AND SYNTHETICS
8-12-6
-------
Cellophane manufacture is performed in three steps: (1) Viscose
preparation, (2) Film casting and (3) Film Coating. Viscose is
prepared in several batch operations in which the raw cellulose
is depolymerized in a caustic solution and is then reacted with
carbon disulfide to make a solution of sodium cellulose
xanthate called viscose. This solution is reacted with sulfuric
acid in the next step to regenerate the cellulose as cellophane.
The caustic solution in the first step is recycled but is
periodically purged, producing a waste stream.
Film is cast by pumping "viscose" through slit-dies into a
spinning bath of sulfuric acid and sodium sulfate. The cello-
phane film is subsequently passed through finishing baths, is
dried and is wound into rolls. In the third step, coatings are
applied to the film from organic solvent solutions. The solvent
from these solutions is recovered and reused.
Waste liquors from the spinning bath are evaporated, crystallized,
and recycled.
Rayon (G) is manufactured by the same process as cellophane
except the regenerated cellulose is recovered as fibers instead
of as film.
Purging of recycled solutions constitute a waste stream.
ABS/SAN (H)
Included in Description (A).
Polyester Resin and Fiber (I)
In this process, the monomer is generated first, then followed
by polymerization. Although many plants still use the batch
polymerization process, continuous polymerization with direct
spinning of the fiber are more common for new facilities. A process
flow diagram is shown in Figure 8-12-2. The ester monomer is
made by reacting an alcohol, usually ethylerie glycol with an
ester forming an "activated" ester.
When the polymerization of the ester takes place continuously,
the molten polymer is fed to spinning heads, forming the polyester
fiber. Wastes associated with this process are primarily unused
monomer and methanol.
8-12-7
-------
Nylon 66 Resin and Fibers (J)
This process is similar to polyester in that the monomer is
generated first, followed by polymerization. Effluents from
activated carbon filtration, evaporators, and scrubbers all
produce waste streams containing small amounts of raw and inter-
mediate chemicals.
Nylon 6 Resin and Fibers (K)
Caprolactam is mixed with catalyst, acetic acid and titanium
dioxide and polymerized. Formation of the resin into strands
and chips as well as monomer recovery processes involve exten-
sive water use.
Cellulose Acetate Resin and Fibers (L)
Cellulose Acetate resin is produced by a batch operation in
which wood pulp is dissolved with strongly acidic materials and
cellulose acetate "flakes" are recovered by an acid reaction to
form a precipitate. The polymer "flakes" are washed to recover
the acids used in the process. Wastewaters are high in dissolved
solids.
The fibers are manufactured by dissolving in acetone the "flakes"
produced by the previous process and by pumping the "dope"
solution through spinnerettes. The acetone solvent recovery
system is the major source of waste.
Acrylics (M)
Acrylonitrile monomer is polymerized in a continuous reactor in
the presence of a catalyst. The polymer is recovered, dried,
and forced through spinnerettes. Solvent losses are a major
contributor to the waste load.
Ethylene-Vinyl Acetate Copolymers (N)
Ethylene-Vinyl Acetate (EVA) is manufactured in the same
facilities as low and high density polyethylene (E). The mono-
mers used in the reaction are vinyl acetate and ethylene.
Polymerization is carried out in an autoclave. The reaction
mass is then sent to a separator, to remove unreacted monomers.
The EVA polymer is then fed to an extruder which forms strands,
which are then cut into pellets.
8-12-8
-------
The cooling water used in the pelletizer is recirculated, but
is purged periodically, producing a waste stream containing
monomers and polymer fines.
Polytetrafluoroethylene (PTFE) (O)
The TFE monomer is produced in the gaseous phase. The product
stream is scrubbed with water and then with dilute caustic
solution to remove byproduct acid and other soluble components.
The gas is then dried with concentrated sulfuric acid or ethy-
lene glycol.
The waste stream produced from the scrubbing processes is acidic
and contains fluoride. If glycol is used as the drying agent,
it contributes to the waste load. PTFE polymer is produced in
a batch operation and sold in a granular or pellet form, fine
powder, or in an aqueous dispersion.
Polypropylene Fibers (P)
The polymerization process has been described under subcategory D,
the Ziegler Process. Polypropylene fibers are made by melt
spinning. The process consists of coloring polypropylene flakes
by dry blending the flakes with pigments, followed by a melting
and extrusion process that forms colored polypropylene pellets.
The pellets are then extruded through a spinnerette into a
column of air which solidifies the molten filaments. The fila-
ments are then stretched or spun into fibers.
Rinsewaters are generated from the blending process. Discharges
from spinning wastes are very high in BOD.
Alkyds and Unsaturated Polyester Resins (Q)
Unsaturated polyester resins are made in a batch process by an
esterification reaction involving several materials derived
from petroleum fractions. Reinforced plastic is made by rein-
forcing the resin with glass or metallic fibers. Nonreinforced
Unsaturated polyester resin is used for castings, coatings and
putty-like compounds.
Alkyds are often manufactured and used interchangeably with
Unsaturated polyesters, since they are chemically very similar.
They are used for paint formulations and in molding compounds.
8-12-9
-------
Wastewaters contain a variety of contaminants as a result of
the polymerization reaction, scrubbers, and equipment washouts,
which are high in BOD, COD, grease and oil.
Cellulose Nitrate (R)
Cellulose Nitrate is produced by reacting cellulose with a
mixture of nitric and sulfuric acids followed by:
Washing to remove acid
Stabilization by boiling with water
Digestion (heating in water)
Dehydration
Wastewaters contain acids, unrecovered alcohols, and suspended
solids.
Polvamides - (Nylon 6/12) (S)
Nylon 6/12 is produced in equipment used regularly for the
production of Nylon 66 and the wastes are similar.
Polyester Resins (thermoplastic) (T)
These resins are produced by the same polymerization process
used for fiber production (I). The two raw materials are ethy-
lene glycol and either dimethyl terephthalate (DMT) or tere-
phthialic acid (TPA) . The two reactants are polymerized in a
reactor. Some integrated plants also produce polyester fibers.
Liquid wastes result from the condensation of steam ejector
vapors. Process materials are present in the waste streams.
Silicones (U)
Plants purchase silicon metal and react it with a wide range
Of chemicals to produce silicpne. In general, silicones are
produced by reacting chloride containing compounds, such as
methyl chloride or phenyl chloride with silicon metal in the
presence of copper catalyst to form chlorosilane, which is a
silicone.
A significant amount of acid wastes often containing copper
are generated due to the formation of hydrochloric acid (HCl)
in the process, in addition, trace amounts of solvent may
be present in the waste stream.
8-12-10
-------
Epoxy Resins (v)
The epoxy resin family should be regarded as intermediates
rather than an end resin itself since they require further
reaction with a second component, or curing agent in order to
yield the final thermoset material. Almost all commercially
produced epoxy resins are made by the reaction between epichloro-
hydrin and bisphenol A. The reaction takes place under alkaline
conditions.
The epoxy resins fall into two broad categories: the low mole-
cular weight liquids and the high molecular weight solids.
The low molecular weight liquid resins can be manufactured by
either batch or continuous processes, while solid resins are
produced by batch processes. Wastewaters contain caustic and salt.
Phenolic Resins (W)
These resins are based upon the reaction between phenol and
formaldehyde. There are two broad types of resins produced by
the industry: resols and novolaks. Resols are formed from a
mixture containing an excess of formaldehyde; novolaks are formed
from a mixture containing a deficiency of formaldehyde. These
resins are generally produced by a batch process.
Wastewaters are generated from the distillation process and the
rinsing procedures.
Urea and Melamine (X) (Amino Resins)
"Amino Resins" are a broad group of polymers formed by batch
process from formaldehyde and various nitrogen containing
organic chemicals such as urea and melamine. The product can
be sold either as a thick syrup or as a solid.
The equipment used for the production of the "first-step" amino
/resins is often also used for the production of other resins
such as phenolics. Between these different uses, and between
production batches of melamine and urea resins, it is customary
to clean the equipment with hot dilute caustic solution. This
material is drained as process waste.
4. wastewater Characterization
Tables 8-12-1 and 8-12-2 contain raw wastewater characteristics
for the industry.
8-12-11
-------
WASTE PARAMETER
E*
TABLE 8-12-1
PLASTICS AND SYNTHETICS INDUSTRY
RAW HASTEWATER CHARACTERISTICS
SUBCATEGORIES
K L M
P Q R
O.6MM 0.3MM
Plow Type
BOD
TSS
00 COD
I
K-1 COLOR
KJ
I MERCURY
I-1
|O CHROMIUM
COPPER
ZIKC
CYANIDES
COBALT
IRON )
TITAIIIUM )
CADMIUM )
Nicm. )
VANADIUM )
OIL AM) CREASE )
B
350
1600'
B
1500 '
0.8MM
B
UOO
1500*
8.3MM
aoo
0.8MM O.ltlMM l.OMM
B
1200 <
B-C
UUOO*
1300*
UOO
500 2100* 5800* 8100*
900* 160
1700*
Hay be Present in all Subcategories
B - Bath Process
C - Continuous Process
NOTE - M - = 1,000
MM = 1,000,000
+ Low RpnBity Polynthylone
* See Appendix 5 for parameter* which nay be inhibitory to biological «yitems.
530-
1»5M
B
3000*
uooo*
270M-
7MM
B-C B B
300 650* 1500* 1300 *
700 23OO* 500O* 6500 *
-------
WASTE PARAMETER
TABLE 8.12-2
MASTEWATER. CHARACTEJUIAnON
FUSTICS AND SYNTHETICS INDUSTRT
PUODUCT1UN BACISD BATA
SUBCATEUORIES
ABCD E FGKi j
Plow Range - CM/ntc'1' 2.S - 42 0-25 0 - 142 2.5 - 67 0-42 100 - 560 33 - 192 1.7 - 24 0 - 170 0-152
Flow Type
BOO Kg/KKG{2) 0.1-48 0-2 0-3 0-10 0-5 20 - 133 20 - 45 2-21 3 . 20 0-135
TTS Kg/XKG 1-30 0-2 0-8.4 - fl-4 6-70 - 0-30 0-12 g-8
GO
1 COD Kg/KXG 0.2-100 0-3 0-6 0-20 0-54 40 - 334 33-100 5-34 6 _ 4J 0-300
IO Zinc 12 - 50
1
10
K L
0-152 16 - 423
0-135 6-70
0-8 2-20
0-390 11 - 100
M N 0 PQKS T U V w x
Flow Range - CM/KKG 2.5 - 51 2.3 - 2.5 18-153 1-3-31 0.3 - 12 111 - 170
Flow Type
BOD Kg/KXG (2) 10 - 40 0.4 - 4.4 0-7 0.4-1 9 - 25 55 - 110
TTS Kcj/HKG 0-2 0-4 2.2-6.6 0.2 - 2.2 1-2 35
COD KG/KKG 10 - 70 0.2 - 54" 4.4 - 44 1.8 - 3 15-80 75 - 275
2.2 - 6.4 8.3 - 280 2.5 .5 0-5 . 2
0-10 5 - 110 60 . 85 15 . M
-W 5-25 0-7
1-30 15 - 200
30 - 127 90 - 65
Z 13
S60
(1) CM/KKG Cubic Meters/1000 kg product produced/
(2) KG/XXG (kilograms/1000 kg product produced)
-------
5. Control and Treatment Technology
In-Plant Control
A major source of waterborne pollutants is attributable to
spills, leaks and accidents. The following list of spill pre-
vention and control techniques apply to the synthetic and
plastic industry:
Dike areas around storage tanks
Install tank level indicators and alarms
Curb process areas
Install holding lagoons for general plant area
Treatment Technology
Wastewater treatment technology in this industry relies heavily
upon the use of biological treatment methods preceded by pH
adjustment, equalization, and primary solids removal.
COD/BOD ratios in the plastics and synthetic industry range from
4-12, which indicate the presence of substances which are not
biodegradable. Removal efficiencies of these substances vary
markedly from one subcategory to another. In general, longer
residence times are required to treat wastes from this industry
than for municipal wastes. Detention times of 500-900 hours=have
been reported for some plants. Of all the subcategories, acrylic
wastes represent the most difficult treatment problems. Equaliza-
tion prior to discharge to municipal treatment plant can help
to maximize POTW efficiency.
Water recycle has not been practiced due to two factors:
(1) The industry, except for cellulosics, is a relatively low
user of water per unit of product, and (2) High quality process
water is often required in order to maintain product quality.
Table 8-12-3 gives removal efficiencies for certain treatment
methods practiced by this industry.
8-12-14
-------
TABLE 8-12-3
Plastics and Synthetics Industry
Wastewater Treatment Practices
BOD Removal
Neutralization, Equalization,
Clarification, and Biological
Treatment
Subcategories G, K,M, R, U
80-87
Removal Efficiencies (%)
Subcategories A,B,E,H,I,J,Q,V,X
95-99
oo
I
NJ
COD Removal
Neutralization, Equalization,
Clarification, and Biological
Treatment
Subcategories B, G
0-30
Subcategories V, W
85
Subcategories D,M, U
60-70
Subcategories A,E,H,I,J,N,Q,X
90-95
-------
SOAP AND DETERGENTS
1. Industry Description
The Soap and Detergent Industry produces liquid and solid
cleaning agents for domestic and industrial use, including
laundry, dishwashing, bar soaps, specialty cleaners and
industrial cleaning products. The discharges are generally
non-toxic and readily responsive to treatment except in the
industrial surfactant area. More than 95% of plant effluents
go to municipal treatment plants.
The industry is broadly divided into two categories: soap
manufacture which is based on processing of natural fat, and
detergent manufacture which is based on the processing of
petrochemicals.
This industrial category includes Standard Industrial Classification
(SIC) 2841 and includes establishments primarily engaged in manufac-
ture of soap, synthetic organic detergents, inorganic alkaline deter-
gents or any combinations thereof and establishments producing
crude and refined glycerine from vegetable and animal fats and
oils. Excluded from this category are establishments primarily
engaged in the manufacturing Of shampoo or shaving products
whether from soap or synthetic detergents (SIC 2844) and the
synthetic glycerine industry (SIC 2869). Also excluded are
specialty cleaners, polishing and sanitation preparations.
2. Industrial Categorization
A useful categorization system for the purposes of raw waste
characterization and the establishment of pretreatment informa-
tion are the following subcategories:
SOAP AND DETERGENT CATEGORIZATION
Main Category Subcategory Designation
Soap Manufacture Batch Kettle and Continuous A
Fatty Acid Manufacture by Fat
Splitting B
Soap from Fatty Acid Neutralization C
Glycerine Recovery
Glycerine Concentration D
Glycerine Distillation E
Soap Flakes and Powders F
Bar Soaps G
Liquid Soap H
Detergent Oleum Sulfonation & Sulfation
Manufacture (Batch & Continuous) I
Air-S03 Sulfation & Sulfonation
(Batch & Continuous) J
S03 Solvent & Vacuum Sulfonation K
8-13-1
-------
Soap and Detergent Categorization continued
Main Category Subcategory Designation
Sulfamic Acid Sulfation L
Chlorosulfonic Acid Sulfation M
Neutralization of Sulfuric Acid
Esters & Sulfonic _Acids N
Spray Dried Detergents 0
Liquid Detergent Manufacture P
Detergent Manufacturing by
Dry Blending Q
Drum Dried Detergents R
Detergent Bars & Cakes S
3. Process Description
A flow diagram for the,entire industry is shown in Figure
8-13-1.
Soap_Manufacture and Processing
Soap manufacturing consists of two major operations: the
production of neat soap (65-70% hot soap solution) and the
preparation and packaging of finished products into flakes
and powders, (F), bar soaps (G) and liquid soaps (H). Many
producers of neat soap also recover glycerine as a by-product
for subsequent concentration (D) and distillation (E).
Neat soap is generally produced in either of two processes:
a. The batch kettle process (A), or
b. The fatty acid neutralization process, which is
preceded by the fat splitting process (B,C).
Descriptions of the production of neat soap will follow. Process
flow diagrams are shown in Figure 8-13-2.
Production of Neat Soap
Batch Kettle Process(A) - The production of neat soap by
batch kettle consists of the following operations:
. Receiving and Storage of Raw Materials
. Fat Refining and Bleaching
. Soap Boiling
The major wastewater sources are the washouts of both the storage
and the refining tanks, as well as from leaks and spills of fats
and oils around these tanks. These streams are usually skimmed
for fat recovery prior to discharge to the sewer.
8-13-2
-------
CO
I
I
U)
Fatty Oils (Coconut, etc.) ]
Clay I (A)
? \, ,.,, I i fc- Fatty Acids & Cau
Caustic boda i _J
w Neat Soap
1 .... i \
Clay 1, , Fatty Acid fn Rl w
Caustic Soda y ' > Manul'acture J.
Hydrocarbon or (1_^ Sulfatlon
411:01101 -H> or ^_SjOfated Acid
SoLfuration r
Builders
^ 4-
^ ' Additives
(F) ^
^
fHl k.
(N)
1~i T
(0) .
(P) w
(a) ^
fa) k
fs) ^
Glycerine Recovery
Flakes end Powders
Bar Soaps
Spray
Liquid Detergent
Dry Detergent Blending
Drum Dried Detergent
Bars and Cakes
t
fc,
w^
FINISHED
DETERGENTS
SOAP AND DETERGENT MANUFACTURE
Figure &-13-1
-------
SOAP MANUFAC1 URC DY DATCH KETTLE
RECEIVING
STORAGE TRANSFER
ANDBl EACHING
SOAP BOILING
CLAY
FATTY OILS
COCONUT. TALLOW
CAUSTIC SODA
n
i i
n
i i
pi
1 1
i i
i
WASHOUTS
\|
BOILING
MIXER
SETTLER
11
1 MIXER
4. SETTLER
r
ii
1
i
=53
CLAY
BLEACHING
FILTER
-» I
1
STEAM
.-STEAM
STEAM-
SALT
SALT.
p.
I^LOWCRACI
\
\
SOAP
ROILING
KE1TLE
I " [-
i PROCESSING
t 1
1
t » »
COMPENSATE - WASTE WATER
GLYCERINE TO
'RECOVkRV
. LOWGRADE SOAP
LOW GRADE
FATTY ACID
FATTY ACID MANUFACTURE BY FAT SPLITTING (B)
FAT FflE TREATMENT
FAT SPLITTING
FATTY ACID DISTILLATION
tSTCWATLR I [ SOI ID WASTE 1 I WASH IN)
PROCESS CONDENSATE
.uw.c AC.O-,1 ,IS1 Qi^r.oN **,
^ ,' atm L^|EMULSIO.BB».^I; ,«,
PRESSURE | ^f^?,1.,... ' J »ATll^»R*T.ON Lai-FITCH *NO
.°.[DUCIIO-i ljp-?Qir.coV|.Y I J «HIT««Lll» |i M1IIHIU
SOAP FROM FATTY ACID NEUTRALIZATION (C)
RECEIVING SAPON1FICATION RECYCLE-RfF
STORAGE TRANSFER
CAUSTIC SOOA
SODA ASH
POTASSIUM HYDROXIDE
SODIUM CHLORIDE
1 L
1 TX^
1 1 1
-n
i i
n
i
LEAKS. SPILLS. STORM
RUNOF FS. WASHOUTS.
MIXER
r
L,
WASHOUTS
SOAP TO
ACCESSING
REACTOR
1
1
1
1
1
1
I
^p
OFF DUALITY SOAP
TO LANDFILL
WASHOUTS
- SCRAP SOAP
- CAUSTIC SODA
1
SEWER LYES
FIGURE 8-13-2
NEAT SOAP MANUFACTURE
PROCESS FLOW DIAGRAMS
8-13-4
-------
The fat refining and bleaching operation is carried out to
remove impurities which would cause color and odor in the
finished soap. The wastewater from this source has a high
soap concentration, treatment chemicals, fatty impurities,
emulsified fats, and sulfuric acid solutions of fatty acids.
Where steam is used for heating, the condensate may contain
low molecular weight fatty acids, which are highly odorous,
partially soluble materials.
The soap boiling process produces two concentrated waste
streams: sewer lyes which result from the reclaiming of scrap
soap and the brine from Nigre processing. Both of these
wastes are low volume, high pH with BOD's as high as 45,000
mg/1.
Fatty Acid Neutralization (C) - Soap produced by the neutraliza-
tion process is a two step process:
Fat + Water Fatty Acid + Glycerine (Fat Splitting) (B)
Fatty Acid + Caustic Soap (Fatty Acid Neutralization) (C)
Fat Splitting - The manufacture of fatty acid from fat is
called fat splitting (B). Washouts from the storage, transfer
and pretreatment stages are the same as those for process (A).
Process condensate and barometric condensate from fat splitting
will be contaminated with fatty acids and glycerine streams,
which are settled and skimmed to recover the insoluble fatty
acids which are processed for sale. The water will typically
circulate through a cooling tower and be reused. Occasional
purges of part of this stream to the sewer releases high con-
centrations of BOD and some grease and oil.
In the fatty acid distillation process, wastewater is generated
as a result of an acidification process, which breaks the
emulsion. This wastewater is neutralized and sent to the sewer.
It 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.
Fatty Acid Neutralization(C) - goapmaking by fatty acid neutral-
ization is a faster process than the kettle boil process and
generates less wastewater effluent. Becuase it is faster,
simpler and cleaner than the kettle boil process, it is the
preferred process among the larger as well as the smaller manu-
facturers.
8-13-5
-------
Often, sodium carbonate is used in place of caustic. When
liquid soaps (at room temperature) are desired, the more
soluble potassium soaps are made by substituting potassium
hydroxide for the sodium hydroxide (lye). 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
wastewater of consequence - the sewer lyes from reclaiming
of scrap. The sewer lyes contain the excess caustic soda
and salt added to grain out the soap. Also, they con+v^n
some dirt and paper not removed in the strainer.
Glycerine Recovery Process (D,E)- A process flow diagram for
the glycerine recovery process uses the glycerine by-products
from kettle boiling (A) and fat splitting (B). The process
consists of three steps:
1. Pretreatment to remove impurities
2. Concentration of glycerine by evaporation
3. Distillation to a finished product of 98% purity
(See Figure 8-13-3)
There are three wastewaters of consequence from this process:
Two barometric condensates - one from evaporation; one from
distillation; plus the glycerine foots or still bottoms.
Contaminants from the condensates are essentially glycerine
with a little entrained salt. In the distillation process,
the glycerine foots or still bottoms leave a glassy dark
brown amorphous solid rich in salt which is disposed of into
the wastewater stream. It contains glycerine, glycerine
polymers and salt. The organics will contribute to BOD,.,
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.
Glycerine can also be purified by use of ion exchange resins
to remove the sodium chloride salt followed by evaporation
of the water. This process puts additional salts into the
wastewater but results in less organic contamination.
Production of Finished Soaps
The production of finished soaps utilizes the neat soap
produced in processes A and C to prepare and package finished
soap. These finished products are soap flakes and powders(F),
bar soaps (G) and liquid soap (H). See Figure 8-13-4.
8-13-6
-------
RECEIVING
STORAGE-TRANSFER
LYE TREATMENT
GLYCERINE EVAPORATION
GLYCERINE STILL
oo
I
CO
I
SWEET WATERS
AND LYES
TREATED
__ GLYCERINE
I LIQUOR
i - RECYCLE
STEAM
CRUDE
GLYCERINE
SALT RECYCLE
TO SOAP
MANUFACTURE
STEAM
JLJ
GLYCERINE
FOOTS
SOLID WASTE
BAROMETRIC
CONDENSATE
COOLING TOWER
BLOWDOWN
FIGURE 8-13-3 (D,E)
GLYCERINE RECOVERY
PROCESS FLOW DIAGRAM
-------
SOAt'FLAKI.S ANOPOWOLIIS (D
MICIIVING
SIOHAGl 1HANSI IN
M»lSO*rs
lUUntHS
MXXTIVU .
D
J L
-LJ-
n
f 11 UH "
SIRAINIH ~
1-,
T
L
f
t
i
i
i
i
i
*»i
H
DMVIMO
KAKINti
CHUICHINU DIIYING
J CMU
1 K
|
1
1
1
1
1
UEH 1
3RYCR 1
SfRAV DHVIfJO
CAS
| 1 , F1AKI S TO
i PACKAGING
SCHUDHEH
WASTEVkATCfl
lO-'.VI
RUNOFFS, WASHOUTS
IM/O;
U 1-
[1HYIR J 1
klfARATOn
SOAP TO
RtCYCLt
f COOL I H MIXER U
/
WASTCWATtH
(U)MP
RUNOFFS, WASHOUTS.
IOUDJ
1
i
i
'{
^
' k
r
PACKAGING
WATIM
FLAKES-
,AODI
TIVCS
V
GASES
PACKAGING -
EQUIPMENT
i
1
T
SCRUCIflEfl
VSASTtWATtn
i&Ajl
tTN*r
* lOidAP
M1CVCLI
~l
PACKAGED
SOAP TO
WARCHOUS
BAR SOAPS (G)
MEAT tOAf-Lf
CRUTCHING AND DRYING
flLHR
STRAINER
,. TO SOAP
MILLING
SOAP MILLING
MIXER | | PLODDER |
WASTE WATER
IOC 301,
J CUTTtB
|»
ESS
WRAPPER L
SCRAP TO
*5OAP
RECYCLE
FINISHED SOAP
-BARS AND CAKES
TO WAREHOUSE
LIQUID SOAP PROCESSING <«>
RECEIVING
STORAGE TRANSFER
POTASSIUM SOAPS
ADDITIVES
_l
ICA
Rur
c
KS ',P
OF»S.
us r.rouM
WA:,MOUIS
x
/
X
/
BLENDING
BLENDER
'
WArHDOWNV
HLtLS
PACKAGING
PACKAGING
f
WASHOUTS
LIQUID SOAPS
FIGURE 8-13-4
PRODUCTION OF FINISHED SOAPS PROCESS FLOW DIAGRAMS
8-13-8
-------
Flakes and Powders (F) - Neat soap 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 through various mechanical
operations to produce flakes and powders. Since all of the
evaporated moisture goes to the atmosphere, there is no
wastewater effluent.
Some operations will include a scrap soap reboil to recover
reclaimed soap. The soap reboil is salted out for soap
recovery and the 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 flows over the pump shaft, picking up any minor leaks.
This will contribute a very small, but finite, effluent loading.
There are a number of possible effluents shown on the flow
diagrams for Process F. However, survey of the industry showed
that most operating plants either recycled any wastewater to
extinction or used dry clean-up processes. Occasionally, water
will be used for clean-up.
Bar Soaps (G) - The procedure for bar soap manufacture (G) will
vary significantly from plant to plant, depending upon the
particular clientele served.
The amount of water used in bar soap manufacture varies greatly.
In many cases, the entire bar soap processing operation is
done without generating a single wastewater stream. The
equipment is all cleaned dry, without any washups. In other
cases, due to housekeeping requirements associated with the
particular bar soap processes, there are one or more wastewater
streams from air scrubbers.
The major waste streams in bar soap manufacture are the filter
backwash, scrubber waters or condensate from a vacuum drier
and water from equipment washdown. The main contaminant of
all these streams is soap which will contribute primarily
to BOD and COD.
Liquid Soap (H) - In the making of liquid soap, neat soap
(often the potassium soap of fatty acids) is blended in a
mixing tank with other ingredients such as alcohols or glycols
to produce a finished product, or the pine oil and kerosene
for a product with greater solvency and versatility. The
final blended product may be, and often is, filtered to achieve
8-13-9
-------
a sparkling clarity before being drummed. In making liquid
soap, water is used to wash out the filter press and other
equipment. According to manufacturers, there are very little
effluent leaks. Spills can be recycled or handled dry- Wash-
out between batches is usually unnecessary or can be recycled
to extinction.
Detergent Manufacturing and Processing
Detergents can be formulated with a variety of organic and
inorganic chemicals depending upon the cleaning characteristics
desired. There are four main groups of detergents:
Anionics Amphoterics
Cationics Nonionics
Anionics comprise the most important group of detergents.
They are usually the sodium salts of an organic sulfate or
sulfonate of animal or petroleum origin.
Cationic detergents are known as "inverted soaps" and are
produced in quite small volumes. They are relatively expensive
and somewhat harsh on the skin. They make excellent bacterio-
stats and fabric softeners and are used for this purpose.
Nonionic detergents are an increasingly popular active ingre-
dient of automatic washing machine formulations. These products
are effective in hard water and are very low fearners. They are
made by the addition of ethylene oxide to an alcohol.
Amphoterics are those detergents which can be either anionic
or cationic, depending upon the pH of the system wherein they
work. They account for only a small portion of the detergent
market.
A finished, packaged detergent customarily consists of two
main components - the active ingredient (surfactant) and the
builder. The surfactant acts as the cleaning agent while the
builder performs such functions as buffering the pH, soil
dispersion, and antisoil redeposition. The processes described
will include the manufacture of the surfactant as well as the
preparation of the finished detergent.
Production of the surfactant is generally a two-step process":
*. Sulfation or sulfonation
. Neutralization
Refer to flow diagram 8-13-1,
8-13-10
-------
Oleum Sulfonation/Sulfation (I) - One of the most im-
portant active ingredients of detergents is the sulfate
or sulfonate compounds made via the oleum route. A proc-
ess flow diagram is shown in Figure 8-13-5. In most
cases the sulfonation/sulfation is carried out continu-
ously in a reactor where the oleum (a solution of sulfur
trioxide in sulfuric acid) is brought into intimate con-
tact with the hydrocarbon or alcohol. Reaction is rapid.
The stream is then mixed with water where the surfactant
separates out and is then sent to a settler. The spent
acid is drawn off and usually sent for reprocessing, and
the sulfonated/sulfated material is sent to be neutral-
ized.
This process is normally operated continuously and per-
forms indefinitely without need of periodic cleanout.
A stream of water is generally played over pump shafts
to pick up leaks as well as to cool the pumps. Waste-
water flow from this source is quite modest but continual.
Air - 50-3 Sulfation/Sulfonation (J) - This process for
Surfactant manufacture has many" advantages and is used
extensively. With SO., sulfation, ,no water is generated
in the reaction. A process flow diagram is shown in Fig-
ure 9-13-5. SO, can be generated at the plant by burn-
ing sulfur or sulfur dioxide with air instead of obtain-
ing it as a liquid.
Because of this reaction's particular tendency to char
the product, the reactor system ;imust be cleaned thor-
oughly on a regular basis. In addition, there are usu-
ally several airborne sulfonic acid streams which must
be scrubbed, with the wastewater going to the sewer dur-
ing sulfation.
SO- Solvent and Vacuum Sulfonation (K) - Undiluted SO-
and organic reactant are fed into the vacuum reactor
through a mixing nozzle. A process flow diagram is-shown
in Figure 8-13-5.This system produces a high quality
product. Offsetting this is the high operating cost of
maintaining the vacuum. Other than occasional washout,
the process is essentially free of wastewater genera-
tion.
Sulfamic Acid Sulfation (L) - Sulfamic acid is a mild
sulfating agent and is used only in very specialized
quality areas because of the high reagent price. A proc-
ess flow diagram is shown in Figure 8-13-6. Washouts
are the only wastewater effluents from this process.
8-13-11
-------
OLLUM SULFATION AND SULFONATlON (RAICH AND CONT IMUOUSI(I)
RfCHVIMG
STOHAl.t TftANSIlH
SUIFONA1IQN
. 5ULFONIC ACIO
ANDSUIFUKIC
ACIO ISUR TO
NEUIRAIIZATION
AIR-SO, SULFATION AND SULFONATlON (BATCH AND CONTINUOUS)(J>
RECEIVING
STORAGE-TRANSFER
SULFUR BURNING
SULFONATION-SULFATION
Oj LIQUID-
ALKYL BENZENE.
CTHOXVLATES
u
n
~S
i j
\ i
\
i
VAPO
nizEH
\
| I CONDENSATE
1 1
RUNOFFS, WASHOUTS.
AIR
-STSAM
BURNER
^
-»
CONVERTER
DRYER
\
* AIR & SO3
SCHUB3E.a
SCRUBOEfl C^
REACTOR
( r
\
\
\
WASHOUTS
I
1
1
I
i
-f-
I
i
t WATER
CAUSTIC
SULFONI
..SULFUHI
TO NEU1
AND SAL
SO3 SOLVENT AND VACUUM SULFONATlON
RECEIVING
STORAGE -TRANSFER
SULFONATlON
SULFONATlON
ALKVL BENZENE
ETHOXYLATES
a7*"
i
i
i
i
i i
.i i
T 1
A \
\
LEAKS. SPILLS.
STOIIM IIUNOFFS.
HASIIOUIS
\
VACUUM
* so,
REACTOR
STEAM JET fr-
^
C-
^
-> VAPORIZER
LOWER 1
*-
^
t f-~
1
| «/ *
1 CONDENSAT
1 1
1
l-_J WASHOUTS
+ SULfONIC
ACID
-m.-
ONtHNSATE
HREFRIGERATIOfJ
SO,
-» SO, TO
STORAGE
LIQUID
* S°'
# REACTOR
-»
SCRUnOEH |SC
T I
DEGASSER -V-
i
WASTtWATER
if
WASHOUTS
FIGUI^E 8-13-5
SULFATION AND SULFONATlON BY THREE DIFFERENT PROCESSES
8-13-12
-------
SULFAMIC ACIO SULFATION (I.)
ALCOHOLS-
ETHOXVLATES-
SULFAMIC ACID-
00
I
H«
U»
I
M
IV
RECEIVING
STORAGE-TRANSFER
SULFATION
LEAKS, SPILLS. STORM
RUNOFFS. WASHOUTS.
WATER
"f^-CAUSTIC
AMMONIUM ALKYL.
SULFATES
CHLOROSULFONIC ACID SULFATION (M)
MECEIVINO
ITOQACE-TRANSFCH
ALCOHOl
"^s,.
^\^
X
d«
«f
HEACTOR
UBBER C
1
1
.WATER
~ CAUSTIC
ALKVL SULFUR1C ACIO ESTER
TO NEUTRALIZATION
LEAKS. SPILLS. STORM
RUNOFFS, WASHOUTS.
WASTEWATER
WASHOUTS
FIGURE 8-13-6
SOLTATIdJ BY TWO DIPTERENT PROCESSES
-------
Chlorosulfonic Acid Sulfation (M) - For products requir-
ing high quality sulfates, chlorosulfonic acid is an
excellent agent. It is a corrosive agent and generates
hydrochloric acid as a by-product. A process flow diagram
is shown in Figure '8-13-6. The effluent washouts are mini-
mal.
Neutralization of Sulfuric Acid Esters and Sulfonic Acids
(N) - This step is essential in the manufacture of deter-
gent active ingredients. It converts the sulfonic acids
or sulfuric acid esters (products produced by processes
I - M) into neutral surfactants. It is a potential source
\of some oil and grease. Occasional leaks and spills
\around the pump and valves are the only expected source
of wastewater contamination. A process fl©w diagram is
shown in Figure 8-13-7.
Spray-Dried Detergents (0) - In this segment of the proc-
essing, the neutralized sulfonates and/or sulfates are
first blended with builders and additives in the crut-
cher. The slurry is then pumped to the top of a spray
tower of about 4.5-6.1 m (15-20 ft.) in diameter by
45-61 m (150-200 ft.) high where nozzles spray out deter-
gent slurry. A large volume of hot air enters the bot-
tom of the tower and rises to meet the falling detergent.
The design preparation of this step will determine the
detergent particle,1 s shape, size and density, which in
turn, determines its solubility rate in the washing proc-
ess.
The air coming from the tower will be carrying dust part-
icles which must be scrubbed, thus generating a waste-
water stream. The spray towers are periodically shut
down and cleaned. The tower walls are scraped and thor-
oughly washed down. The final step is mandatory since
the manufacturers must be very careful to avoid contami-
nation to the subsequent formulation.
Wastewater streams are rather numerous. (See flow dia-
gram Figure 8-13-3. They include many washouts of equip-
ment from the crutchers to the spray tower itself. One
wastewater flow which has high loadings is that of the
air scrubber which cleans and cools the hot gases-existing
from this tower.
All of the plants recycle some of the wastewater generated.
Some of the plants recycle all of the flows generated.
8-13-14
-------
GO
I
I-1
tn
NEUTRALIZATION OF SULFURIC ACID ESTERS AND SULFONIC ACIDS (N)
RECEIVING
STORAGE-TRANSFER
LIQUID NEUTRALIZATION
DRY NEUTRALIZATION
ACIDS:
SULFURIC ACID ESTERS
SULFONIC ACIDS
BASES-
OTHER INGREDIENTS:
WATER; SOLVENTS-
HYDROTROPES;
ADDITIVES
WATER
CAUSTIC
ACIDS
LIQUID PRODUCTS
AND SLURRIES TO
SALE, BLENDING.
OR CRUTCHING
DRY PRODUCTS
TO STORAGE
WATER
INGREDIENTS:
FIGURE '8-13-7
NEUTRALIZATION OF SULFURIC ACID ESTERS
AND SULFONIC ACIDS
-------
SPRAY DRIED DETERGENTS (0)
RECEIVING
STORAGE TRANSF EH
CRUTCHINC
SPRAY DRYING
BLENDING AND PACKAGING
ACTIVES:
LAS SLURRY; ALCOHOL
SULFATE SLURRY;
ETHOXVLATES
BUILDERS:
PHOSPHATES. SILICATES:
CARBONATES: SULFATES.
BORATES .
ADDITIVES:
AMIDES: SOAPS: FLOUR
E SCENT WHITENERS:
PERFUMES: DYES: PER
BORATE; CMC: ANTICAKING
AGENTS: ENZYMES
WAT
ADOITI
. WA
TO CRUTC
- BLENDER
PACKAGIN
WATER
^V
ADOITIVf
WATE
\
R -
> CRUTCHER
.ENDER AND
tCKAGING
-
+
*,
+
MIXER 1 I jyjJL-,,.
CRUTCHER
/
HOLD TANK
HIGH-
PRESSURE
PUMP
tr
i
i
f
\
\
JOE AERATOR) '
M -1
STEAM JET
- \
\\
; i
__l
SOLID WASTES
1
WASTEWATCH 1
WATER
WASMDOWN
WATER
FLUE GAS
1
1
CYCLONE j-^ SCRUBBER [ «
f
" ELECTROSTATIC
SPHAV PRECIPITATOR
1
1
< 1
CONV£ytRV V STORAGE f
*^ i
*t \ ^ ^
f *
|WAS"WATER WASHDOYM WATER WASTEWATCR
1 TO WASTE OR
CRUTCHER
-WATER
ADDITIVES.
BUILDERS.
AND ACTIVES
FROM >»>
\
\ \
%^ \
XN X
1 \ \
i . \
1 VENTGkSES \
FUME AND
DUST SCRUBS
CR DRY OUST
COLLECTOR
"^ '*ST pAC
MIXER
ER ,
KAGING
IPMENT
1
!
| WASTEWATE
i
\
N
R «
O>
FINISHED
. DETERGENTS
TO WAREHOUSE
SCRAP TO RECYCLE
OR SOLID WASTC
|_ _ ^_
WASTCWATCR
* * I
I t I I WASH
iTtTI ^ ~T
SOLID WASTES
FIGURE &-13-8
SPRAY DRIED DETERGENTS
-------
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.
After the powder comes from the spray tower it is further
blended and then packaged.
Liquid Detergents (P) - Detergent actives are pumped into
mixing tanks where they are blended with numerous ingredi-
ents, ranging from perfumes to dyes. A process flow dia-
gram is shown in Figure 8-13-9. From here, the fully formu-
lated liquid detergent is run down to the filling line for
filling, capping, labeling, etc. Whenever the filling line
is to change to a different product, the filling system must
be thoroughly cleaned out to avoid cross contamination.
Dry Detergent Blending (Q) - Fully dried surfactant materials
are blended with additives in dry mixers. Normal operation
will see many succeeding batches of detergent mixed in the
same equipment without anything but dry cleaning. However,
when a change in formulation occurs, the equipment must be
completely washed down. A modest amount of wastewater is
generated. A process flow diagram is shown in Figure 8-13-9.
Drum Dried Detergents (R) - This process is one method of convert-
ing liquid slurry to a powder, and should be essentially free
of generation of wastewater discharge other than occasional
washdown. A process 'flow diagram is shown in Figure 8-13-9.
Detergent Bars and Cakes (S) - Detergent bars are either 100%
synthetic detergent or a blend of detergent and soap. They
are blended in essentially the same manner as that used for
conventional,soap. Fairly frequent cleanups generate a waste-
water stream. A process flow diagram is shown in Figure 8-13-10.
4. Wastewater Characteristics
tfable 8-13-1 and 8-13-2 contain the characteristics of
the wastewaters from the seventeen subcategories of the
industry. Most plants contain two or several of the subcate-
gories shown on the table and their wastewaters will be a
composite of these individual unit processes.
8-13-17
-------
LIQUID DETERGENT MANUFACTURE (p)
ACTIVES
LAS SlltFQNIC ACtO,
OUMNSUIFONATES.
ETHEH SULIUNA-TIS
AMINE OXIDES. AMIDES
UIL.pt "S,
PHOSPHATES. SILICATES
ADDITIVES
HVpflOTHOPES.
SOLVENTS. COLOR;
PERFUME
R(Cf IVING
sioHAui IRAN;
-^
\
{
ftft
WATER-
BLINDING
STORAGE
MIXERS
WATER
TREATMENT
I.
PACKAGING
1
I
1
1
BULK
SALES
, f PACKAGING
CQUIPMINT
WASH DOWN
WASHOUTS
HEELS
CASE GOODS
1O WAREHOUSE
CONTAINER
WASHINGS
LEAKS. SPILL.S,
WASHOUTS
SOLID WASTE
DETERGENT MANUFACTURE BY DRY BLENDING
ACTIVES-
LAS SLURRY; FLAKES:
BEADS. SUC FO'. 1C ACID;
AMIDES, ETHOXVLATCS
BUILDERS
SILICATES: CARBONATES: _
PHOSPHATES, BOHATES
ADDITIVES
ABRASIVES. O1ATOMACEOUS
EAHTH; PUMICE
RECEIVING OftY BLENDING
STORAGE TRANSFER
-TV
-O
-Lf
LENOEK
STORAGE
FACKAOim
-» BULK
DETERGENT
SALES
PACKAGING
EQUIPMENT
«. CASE GOODS
TO WAKEHOUSE
I WASHOUTS
[SOLID WASTE
I WASI
DRUM DRIED DETERGENT (R)
BUILDERS ...
RECEIVING DRUM DRYING PACKAGING
STORAGE TRANSFER
-FT-
L_l
-A \
1 1
p4 SCR UPB E **}~l
CRUTCHCR
1
I
i
\
DRUM
OrtilR
STOR
AGt
r J
BULK
DETERGCNT
SALES
PACKAGING
EQUM'MtNT
PACKAGED
WAREHOUSE
WAS!
WAtf R
WASHOUTS
FIGURE 8-13-9
DETERGENT MANUFACTURE
8-13-18
-------
00
1
M
W
M
VD
DETERGENT BARS AND CAKES (S)
RECEIVING MIXING STAMPING-PACKAGING
STORAGE-TRANSFER WORKING-CONDITIONING
i 1 1 " 1
| ' 1 SCRUBBER U - WATER I 1
ACTIVE INGREDIENTS «. .,*. 1
-. ~T BAR
I . III f~~ 1 k.1 I 1 CUTTER \*
BUILDERS _ _ t _ _fc PLODDER / " ' ' ~"
MIXER 1 ' l
ADDITIVES « 1
^* * TABLFT __k_ ._^ PACKAGING
" J MACHINE j'
L 1(
1
1 1 1
1 1 1
1 * \
1 SOLID WASTE WASTEWATER
1
1
[__^ WASHOUTS
BAR
,. STAMPER _» ^JT" * DETERGENTS
* PACKAGbK TO
WAREHOUSE
DETERGENT
* CAKES
! i
* \
WASHOUTS SCRAP SOAP
TO RECYCLE
FIGURE 8-13-10
DETERGENT BARS AND CAKES
-------
TABLE 6-13-1
CO
1
u>
1
Parameter (ag/1)
BOD
COD
IBS
Oil & Grease
PH
Chlorides
line
Bickel
BOAP AID DRERGBflTB ZBDUSTBl
RAH WSTEWSR CHARACTERISTICS
Batch Fat Fatty Acid Glycerine Glycerine Flakes &
Kettle Splitting neutralization Concentration Distillation Fenders Bar Soap Liquid Soap
AB C DEFGH
3600* 6O-3600* 1*OO 1600-3000*
1*267* 115-6000* 1000
1600-61*20 115-6000 775
250* 13-760* 200*
5-13.5 High High Heutral neutral Heutral Heutral Heutral
20M*-I*7M*
Present
Present
Parameter (mfc/l)
Oleum
Sul & Sul
I
Air
Sul & Sul
J
BOD 75-2000* 380-520
COD 220-6000* 920-1589*
TSS 100-3000
Oil & Grease 100-3000*
pH 1-2* 2*-7
Surfactant 250-7000
Boron Present Present
Bate: * See Appendix 5 for parameters which may
SO? Sol
& Vac
X
Sulfamic
Acid Sul.
L
Chloro-
Sulfonic
M
Low Low Low
Present Present Present
be inhibitory to biological systems.
neutral
Sulfuric
n
8.5-6H*
2U5-21M*
Low
Present
Spray
Dried
0
1*8-19M*
150-60M*
Present
Liquid Dry Drum
Det. Blend Dried
P Q H
65-31*00* Beg.
6I*0-UM*
60-2H
Present Present Present
Ban t
Caka*
PTCMBt
M -
-------
vuap 8-13-2
SOAP MID DEXEROBSHT8 JJUJWUU
RAW WSTEHATER CHARACTERISTICS BASED UPON PRODUCTION
00
U)
I
N>
Fat Fatty
Batch Kettle Splitting Acid Heut.
Parameter
1
Flow Range(l/kkg)
Flow Type
2
BOD (kg/kkg)
COD (kg/kkg)
TSS (kg/kkg)
Oil & Grease (kg/kkg)
Parameter
1
Flow Range (1/kkg)
Flow Type
BOD (kg/kkg?
COD (kg/kkg)
TSS (kg/kkg)
mi 4 Grease (kg/kkg)
Chloride (kg/kkg)
Surfactant (kg/kkg)
A
623/2500
B
6
10
i*
9
Oleum
Sul & Sul
I
100/27UO
C
.2
.6
.3
.3
.7
B C
3.3I0.92M 258
B B
12 0.1
22 .25
22 .2
2.5 .05
S03 303 Sol
Sul & Sul & Vac. Sul
J K
2l»9
C B
3 3
9 9
.3 .3
.5 .5
3 3
Glycerine Glycerine Flakes &
Concentration Distillation Powders Bar Soap Liquid Soap
D E F G H
Heg. Heg.
B B B B B
15 5 0.1 3A O.I
30 10 .3 5-7 .3
2 2 .1 5.8 .1
1 1 .1 .4 .1
Sulfamic Chlorosulfonic Neutral Sulfuric Spray Liquid Dry Drum Bars i
Acid Sul Acid Sul Acid Esters Dried Det. Blend Dried Cakes
L H N 0 P Q R S
10/10.70 in/2o8U 625/6250
B B B&C BBBBB
3 3 .10 .1-.8 2-5 .1 .1 7
9 9 ,3 .3-25 »H7 .5 .3 22
.3 .3 .3 .1-1.0 .1 .1 2
.5 .5 .1 Hil-,3 .1 .2
5
3 3 .2 .2-1.5 1.3-3-3 .1 5
ate:
1/kkg liters/1000 kg product produced (lower limit/upper limit)
kg/kkg kilograms per 1000 kilogra
B - Batch
C -^Continuous
H«C - MgUU*
M - Thousand
of product produced
-------
5. Control and Treatment Technology
Control
Significant in-plant control of both waste quantity
and quality is possible particularly in the soap manu-
facturing subcategories where maximum flows may be 100
times the minimum. Considerably less in-plant water
conservation is possible in the detergent industry
where flows per unit of product are smaller.
The largest in-plant modification that could be made is
the changing or replacement of the barometric condensers
(processes A, B, D, E) . The quantity of wastes discharged
from these processes could be significantly reduced by
recycling the barometric cooling water through fat skim-
mers from which valuable fats and- oils could be recov-
ered and then through the cooling towers. The only waste
with this type of cooling would be the continuous small
blowdown from the skimmer. Replacement with surface con-
densers has been used in several plants to reduce both
the waste flow and the quantity of organics wasted.
Significant reduction of water usage is possible in the
manufacture of liquid detergents (P) by the installation
of water recycle piping and tankage and by the use of air
rather than water to blowdown filling lines.
In the production of bar soaps (G) , the volume of dis-
charge and the level of contamination can be reduced
materially by installation of an atmospheric flash evap-
orator ahead of the vacuum drier.
Pollutant carry-over from distillation columns such as
those used in glycerine concentration (D) or fatty acid
separation (B) can be reduced by the use of two additional
special trays.
Treatment- Technology
The industry routinely utilizes a broad range of pre-
treatment processes in control of its effluent. The
treatment methods used are shown in Table 8-13-3.
Also shown in this table are the anticipated removal
efficiencies of the processes on the various pollutants
generated. A composite flow sheet showing a complete
treatment system for the soap and detergent industry is
shown in Figure 8-13-11. As a minimum, even small
plants with batch operations should employ equalization
to smooth out peak discharges. Larger plants with an
8-13-22
-------
Table 8-13-3
Treatment Methods Used in the Soap and Detergent Industry
Pollutant and Metooj
Oil and Grease
API type separation
Efficiency (Percentage of Pollutant Removed)
Up to 90 pex~3nt of free oils and greases.
Variable on emulsified oil.
Carbon adsorption
Up to 95 percent of both free and
emulsified oils.
Flotation
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
Mixed media filtration
Up to 95 percent of free oils.
ciency in removing emulsified
oils unknown.
Effi-
Coagulation-sedimentation
with iron, alum or solid
phase (bentohite, etc.)
Suspended Solids
Mixed media filtration
Coagulation-sedimentation
Up to 95 percent of free oil.
90 percent of emulsified oil.
70-80 percent
50-80 percent
Up to
BOD and COD
Bioconversions (with final
clarifier)
60-95 percent or more
Up to 90 percent
Carbon adsorption
Residual Suspended Solids
Sand or mixe
-------
00
I
N)
TO REGENERATION
BRINE
RAW
WASTE"
ciocoNvnnsiON
\
SLUDGE -RECYCLE
GREASE ft OIL RECOVERY
SLUDGE CONDITIONING
AND
DISPOSAL
SLUDGE
- WASTE
FIGURE 8-13-11
COMPOSITE FLOW SHEET
WASTE TREATMENT
SOAP & DETERGENT INDUSTRY
-------
integrated product line may require both suspended solids
and organics removal in addition. The bulk of the large
solid material in the industry's waste is removed by coagu-
lation and sedimentation. Fine solid material can be
removed by sand or mixed bed filtration applied as a tertiary
step after biological oxidation. Organics removal is typically
provided by either one of several forms of biological oxida-
tion or by powdered or granulated activated carbon adsorption.
A few plants employ reverse osmosis or ion exchange as a
tertiary step for the removal of individual dissolved pollutants
or TDS.
8-13-25
-------
FERTILIZER
3». General Industry Description
This report describes the manufacture of fertilizer based on two
of the three major plant nutrients: nitrogen, phosphate and mix-
tures of the two. The third basic nutrient ^potassium,is not included.
The fertilizer industry produces the primary nutrient source for
the nation's agricultural community. Many of its products are
toxic to aquatic organisms and many are a direct hazard to man
when in a concentrated form.
This industry includes Standard Industrial Classifications(SIC)
2873, 2874 and 2875.
2. Industrial Categorization
Nitrogen based fertilizers can create spectacular crop responses.
Such response, however, is comparatively short lived and can
result in disastrous crop failures unless nitrogen fertilization
is followed with phosphate and potassium fertilization within one
or two years. Figure 8-14-1 is'a product manufacturing flow
diagram for the nitrogen and phosphate fertilizer industry. The
industry subcategorization along process lines is as follows:
Subcategory Designation
Phosphate A
Ammonia B
Urea C
Ammonium Nitrate D
Nitric Acid E
Ammonium Sulfate F
Mixed and Blend Fetilizer G
3. Process Description
Phosphate (A)
The phosphate fertilizer industry is defined as eight separate
processes: phosphate rock grinding, wet process phosphoric acid,
phosphoric acid concentration, phosphoric acid clarification,
normal superphosphate, triple superphosphate, ammonium phosphate
and sulfuric acid. Practically all phosphate manufacturers com-
bine the vapious effluents into a large recycle water system.
It is only when the quantity of recycle water increases beyond
capacity to contain it, that effluent treatment is necessary.
8-14-1
-------
Sulfur and Oxvg«n and
and Water
L(ffon-pi »
Sulfuric Acid
.Manufacture A-8
Sulfuric Acid
Sulfuric
Acid
Phosphoric Acid
Manufacture (A-1,2,
3,4)
Phosphoric Acid
Ammonia
Manufacture B
Ammonia
Nitric Acid
Manufacturer E
Acid ffrom A-8)
Normal Superphosphate
Manufacture A-5
Triple Superphosphate
Manufacture A-6
Ammonium Phosphates
Manufacture A-7
Urea Manufacture C
Ammonium Nitrate
Manufacture D
Ammonium Sulfata F
Sulfurie
Phosphoric A4id (A-l,2,3,<)
Mixed and Blend
Fertilizer Manufacture
G
KGORE 81-14-1
PRODUCT MANUFACTURING
FLOW DIAGRAM
FERTILIZER INDUSTRY
-------
(1) Phosphate Rock Grinding
Phosphate rock is mined and mechanically ground to provide the
optimum particle size required for phosphoric acid production.
There are no liquid effluents.
(2) Wet Process Phosphoric Acid
A process flow diagram is shown in Figure 8-14-2. Insoluble
phosphate rock is changed to the water soluble phosphoric acid
by solubilizing the phosphate rock with an acid, generally sul-
furic or nitric acid. The phosphoric acid produced from the
nitric acid process is blended with other ingredients to produce
a fertilizer. The phosphoric acid produced from the sulfuric
acid process must be concentrated before further use. Minor
quantities of fluorine, iron, aluminum, silica, and uranium are
present in phosphate rock. Of these, fluorine presents the
most serious effluent problem.
(3) Phosphoric Acid Concentration
Phosphoric acid produced with sulfuric acid is of too low a con-
centration to be used for processing. It is, therefore, concen-
trated by evaporation to the 40-54% concentration.
Waste streams will contain fluorine and phosphoric acid.
(4) Phosphoric Acid Clarification
When the phosphoric acid has been concentrated, iron and aluminum
phosphates, gypsum and fluorosilicates become insoluble and can
become problems during acid storage. They are therefore removed
by clarification and/or centrifugation.
(5) Normal Superphosphate
Normal superphosphate is produced by the reaction between ground
phosphate rock and sulfuric acid followed by a three to eight
week curing time. Obnoxious gases are generated.
(6) Triple Superphosphate (TSP)
Triple superphosphate is produced by the reaction between ground
phosphate rock and phosphoric acid by either of two processes.
One utilizes concentrated phosphoric acid and generates obnoxious
gases. The dilute phosphoric acid process permits ready collection
of dusts and obnoxious gases.
(7) Ammonium Phosphate
Ammonium Phosphate, a concentrated water soluble plant food, is
produced by reacting ammonia and phosphoric acid. The resultant
slurry is dried, stored and shipped.
8-14-3
-------
PHOSPHATE
ROCK
I
CONTAMINATED
WATER
oo
I
(2500 ~ 3500 I
GAL/TON)
11000- 14500
l/kkg
OFF GAS
{0 ~ 4500 GAL/TON)
0~ 19,000 l/kkg
COOLING WATER IN
COOLING WATER OUT
TO ATMOSPHERE
CONTAMINATED WATER
(1300- 1500 GAL/TON)
5400 ~ 6300 l/kkg
(1300- 1500 GAL/TON)
5400 ~ 6300 l/kkg
CONTAMINATED
WATER
11,000~ 14,500 l/kkg
(2500 ~ 3500 GAL/TON)
PRODUCT
ACID
STREAM LEGEND
MAJOR LIQUID
MINOR LIQUID
MINOR GAS
FIGURE 8-14-2
WET PROCESS PHOSPHORIC ACID- H2S04 ACIDULATION
FLOW RATE PER TON PO
-------
(8) Sulfuric Acid
Essentially, all sulfuric acid manufactured in this industry is
produced by the "contact" process. The name refers to the fact
that sulfur dioxide (SOO and oxygen (O_) contact each other on
the surface of a catalyst (vanadium pentoxide) fo form sulfur
trioxide (SO.,) gas. Sulfur tiioxide gas is added to water to form
sulfuric acid (H-SOJ. The sulfur dioxide is produced by burning
elemental sulfur in a furnace.
In addition, the process is designed to capture a high percentage
of the energy released by the exothermic chemical reactions
occuring in the oxidation of sulfur to sulfur tioxide. This
energy is used to produce steam which is then utilized for other
plant unit operations or converted to electrical energy. It is
the raw water treatment necessary to condition water for this
steam production that generates essentially all the water effluent
from this process.
Ammonia (B)
Ammonia, the base component for the nitrogen fertilizer industry,
is produced by reacting nitrogen with hydrogen at elevated pres-
sure in the presence of a catalyst. The ammonia plant may include
a complex gas preparation operation to provide feedstock to the
ammonia synthesis section. The raw material source of nitrogen
is air. Hydrogen is available from a variety of sources includ-
ing refinery off-gas and reforming of methane. This process gen-
erates wastewaters containing ammonia, methanol, organics and
trace metals.
Urea (C)
Urea is produced by .reacting carbon dioxide with ammonia at high
pressures and temperatures. After separation of the ammonia
from the unreacted components it is either sold or further con-
centrated.
Ammonium Nitrate (D)
Ammonium Nitrate is produced by reacting ammonia with nitric acid.
The high heat of reaction causes flash vaporization which can be
an air pollution problem, or if condensed, can cause a water
pollution problem.
Nitric Acid (E)
Nitric acid is produced by the ammonia oxidation process. Ammonia
is first reacted with air to produce oxides of nitrogen which are
then further oxidized and absorbed in water producing 55-65%
nitric acid. There are no waste streams from this process.
8-14-5
-------
Ammonium Sulfate (F)
Ammonium sulfate is produced by neutralizing sulfuric acid with
ammonia. This product may utilize virgin ammonia or it may be
manufactured as a by-product in the coke making industry where
ammonia is formed as an off-gas. Wastewaters are generally
collected and recycled.
Mixed and Blend'Fertilizer (G)
Mixed Fertilizer
The raw materials used to produce mixed fertilizer goods include
inorganic acids, solutions, double nutrient fertilizers, and all
types of straight fertilizers. The choice of raw materials is
dependent on the specific nitrogen, phosphate, potassium (N-P-K)
formulation to be produced and the cost of the different possible
materials from which it can be made.
The Mixed Fertilizer process involves the controlled addition of
both dry and liquid raw materials to a granulator. The granulator
is normally a rotary drum, but pug mills are also used. Raw
materials, plus some recycled product material are mixed to form
an essentially homogeneous granular product. Wet granules from
the granulator are discharged into a rotary drier where the
excess water is evaporated. Dried granules from the drier are
sized on vibrating screens. Over and under size granules are
separated for use as recycle material in the granulator. Product
size granules are cooled and conveyed to storage or shipping.
Blend Fertilizer
Raw materials are a combination of granular dry straight and
mixed fertilizer materials with essentially identical particle
size. While many materials can be utilized, the five most com-
monly used are ammonium nitrate, urea, triple superphosphate,
diammonium phosphate, and potash. These raw materials are stored
in a multi-compartmented bin and withdrawn in the precise quanti-
ties needed to produce the nitrogen-phosphorus-potassium (N-P-K)
formulation desired. Raw material addition is normally by batch
weighing. The combination of batch-weighed and granular raw
materials are then conveyed to a mechanical blender for mixing.
From the blender the product is conveyed to storage or shipping.
4. Wastewater Characteristics
Few fertilizer plants discharge to municipal treatment systems.
When retention pond capacities in the phosphate industry are
exceeded, the overflows are treated and discharged. Tables
.8-14-1 and 8-14-2 contain the characteristics of the pond water
in the phosphate subcategory and the recycle-water in the other
subcategories.
8-14-6
-------
Parameter
Phosphate
A
TABLE -14-1
Fertilizer Industry
Raw Wastewater Characteristics
Ammonia
B
Urea
C
Ammonium
Nitrate
D
Nitric Ammonium Mixed &
Acid Sulfate Blend
E F G
oo
Suspended Solids
(mg/1)
PH
Ammonia (mg/1)
Sulfate (mg/1)
^ Chloride (mg/1)
Total Phosphate
(mg/1)
Fluoride (mg/1)
Aluminum (mg/1)
Iron (mg/1)
Urea (mg/1)
Radium 226
(picocuries)
Note:
800-1200
1-2*
450-500*
4000
58
3M-5M
6M-84.5M*
110
85
500-1200*
10M*
40M
300-750*
15M-35M
60-100
* See Appendix 5 for parameters which may be inhibitory 'to
biological systems
M - Thousand
-------
TABLE 8-14-2
Fertilizer Industry
Raw Wastewater Data Based Upon Production
Phosphate
A
Parameter
Flow
Ammonia
B
Urea
C
3300/5500 417/935
1200/1750 19,800
Ammonium
Nitrate
D
208/458
330
Nitric
Acid
E
None
Ammonium
Sulfate
F
Mixed &
Blend
G
oo
I
oo
Urea
Ammonium Nitrate
73,700
15,400
-------
5. Control and Treatment Technology
Contaminated water from the phosphate subcateogry (A) can be
collected in ponds and treated for control of pH, phosphorus and
fluorides. Treatment is by means of a "double liming" or two
stage neutralization procedure,, in which fluorides and phosphates
precipitate out.
Seepage collection and reimpoundment is accomplished by construc-
tion of a seepage collection ditch around the perimeter of the
diked area and erection of a secondary dike.
The sulfuric acid plant will have boiler blowdown and cooling
tower blowdown waste streams, which will be uncontaminated. How-
ever, accidental spills of acid can and do occur. When they
occur, the spills will contaminate the blowdown streams. There-
fore, neutralization facilities should be supplied for the blow-
down waste streams.
Waste streams from the nitrogen fertilizer industry (B, C, D, F)
can be recycled back to the process. There are no wastewaters
from nitric acid production (E).
Mixed Fertilizer (G) treatment technology consists of a closed
loop contaminated water system which includes a retention pond
to settle suspended solids. The water is then recycled back to
the system.
There are no liquid waste streams associated with the Blend
Fertilizer (G) process except where liquid air scrubbers are
used to prevent air pollution. Dry removals of air pollutants
prevent a wastewater stream from being formed.
8-14-9
-------
PETROLEUM
1. General Industry Description
The petroleum refining industry produces consumer goods such
as propane, gasoline, jet fuels, heating oils, lubricating
oils, asphalt, and coke. These materials are derived from
crude oil by means of distillation, catalytic conversion, sol-
vent extraction, and chemical conversion operations. This
industry is covered by Standard Industrial Classification
(SIC) 2911.
2. Industrial Categorization
The industry has been subcategorized along process lines and
with a view toward delineating waste loads:
Subcategory Designation
Topping A
Cracking B
Petrochemical C
Lube D
Integrated E
3. Process Description
Figure 8-15-1 is a process flow diagram for the petroleum
refining industry and shows the interrelationships among the
five subcategories. Each subcategory includes various com-
binations of the process operations described below.
a. Crude Oil and Product Storage
The storage area of the refinery serves to provide a working
supply, equalizes process flow and also acts as a place for
separation of water and suspended solids from the crude oil.
Wastewaters associated with storage of crude oil are high in
oil, suspended solids and COD.
b. Crude Desalting
The crude oil desalting process is a pretreatment step to
remove impurities. Wastewaters containing inorganic salts
and suspended solids are discharged.
8-15-1
-------
Crude Oil
Crude Oil
Storage
Crude Oil
Desalting
00
Ul
I
Crude
Distillation
(Topping)
A
Lube Oi1
Manufacture
D
Cracking
B
Petrochemicals
C
Coke
Manufacture
Gasoline
». Fuel. Oils
Heating Oils
Alcohols
Ketones
Styrene
Etc.
Asphalt
Coke
Lube Oil
NOTE - Integrated subcategory, E, includes aIk of
the processes shown.
Figure g~15-l
Product Manufacturing Flow Diagram
Petroleum Refining
-------
c. Crude Oil Fractionation
Fractionation is the basic refining process for the separation
of crude petroleum into intermediate fractions of specified
boiling point ranges. Wastewaters contain sulfides, ammonia,
chlorides, mercaptans and phenols.
d. Cracking
In this process, heavy oil fractions are converted into lower
molecular weight fractions including domestic heating oils,
high octane gasoline stocks and furnace oils. Three types of
cracking are used: Thermal, catalytic, and hydrocracking.
Thermal cracking is accomplished by heating (480-603 C) with-
out the use of a catalyst. Wastewaters usually contain oils
and distillates, and are high in BOD, COD, ammonia, phenol,
sulfides, and alkalinity.
Catalytic cracking is operated at lower temperatures and pres-
sures than with thermal cracking because of the use of a cata-
lyst. Catalytic cracking units are one of the largest sources
of sour and phenolic Wastewaters in a refinery. The major
pollutants are oil, sulfides, phenols, cyanides, and ammonia.
Regeneration of the catalyst may constitute an air pollution
problem. Hydrocracking is a catalytic cracking process in the
presence of hydrogen and has greater flexibility in adjusting
operations to meet changing product demands. Wastewaters are
high in sulfides and possibly in phenols and ammonia.
e. Hydrocarbon Rebuilding
Higher octane products for use in gasoline may be manufactured
by two hydrocarbon rebuilding techniques: polymerization or
alkylation. Wastewaters are high in sulfides, mercaptans,
ammonia, suspended solids, and"oils. Waste sulfuric acid is
usually recovered.
f. Hydrocarbon Rearrangements
Isomerization and reforming are two process techniques for
obtaining higher octane gasoline blending stock. Isomerization,
a molecular rearrangement process, rather than a decomposition
process, generates no major pollutant discharge. Reforming,
a mild decomposition process, generates low volume discharges
with small quantities of sulfides, ammonia, mercaptans, and
oil present.
8-15-3
-------
g. Solvent Refining
Various solvents are used to improve the quality of a partic-
ular feedstock component. The major pollutants are the sol-
vents themselves, many of which can produce a high BOD.
Under ideal conditions the solvents are continually recircu-
lated. Actually, some solvent is always lost. Oil and solvent
are major wastewater constituents.
h. Hydrotreating
Hydrotreating processes are used to purify and pretreat var-
ious feedstocks by reacting with hydrogen. Contaminants,
including sulfur and nitrogen compounds, odor, color, and gum-
forming materials are removed. The strength and quantity of
wastewaters generated by hydrotreating depends upon the sub-
process and feedstock used. Ammonia and sulfides are present.
Phenols may also be present.
i. Grease Manufacturing
Grease is primarily a soap and lube oil mixture. A small
amount of oil is lost to the wastewater system through leaks
in the pumps. The largest waste loading occurs when the
units are washed.
j. Asphalt Production
Asphalt feedstock is contacted with hot air at 203°C - 280°C
to obtain a desirable asphalt product. Wastewaters contain
high concentrations of oils which have high BOD. Small quan-
tities of phenols may also be present.
k. Product Finishing
Drying and sweetening processes are used to remove sulfur
compounds, water and other impurities from gasoline, kerosene,
jet fuels, domestic heating oils and other middle distillate
products. Spent caustic, large quantities of high BOD and
COD sulfides and phenols are generated. Phenolic caustic
streams are usually sold for recovery of phenolic materials.
Clay and acid treatment to remove color forming and other
undesirable materials further refine lube oil stocks. Acid
wastes high in dissolved and suspended solids, sulfates,
8-15-4
-------
sulfonates and stable oil emulsions are generated. Handling
acid sludge can create additional problems. Some refineries
neutralize the sludge and discharge it to the sewec resulting
in organic and inorganic pollution.
Blending various gasoline stocks and additives and packaging
the products are relatively clean processes. The primary
source of waste material is from tank car washing. These
wash waters are high in emulsified oil. Tetra-ethyl lead,
a gasoline additive, is highly toxic and may be washed into
the sewer.
1. Auxiliary Activities
The manufacture of hydrogen for use in the hydrotreating and
hydrocracking processes is a relatively clean one. A poten-
tial waste source is the desulfurization unit, if utilized,
which contains oil, sulfur compounds and phenol.
Wastewaters are generated in the preparation of boiler feed
water and in boiler blowdown.
The subcategories include various combinations of the processes
previously discussed and are defined as follows:
Topping (A) - Includes all refineries which combine all pro-
cesses except cracking and coking.
Cracking (B) - includes refineries which contain topping, re-
forming and cracking operations. Also included are all first
generation conventional refinery-associated products or inter-
mediates, including benzene-toluene-xylene (BTX), alkanes,
alkenes, alkynes, hydrogen and coke whose production is less
than 15 percent of the refinery throughput.
Petrochemical (C) - Includes topping, cracking and petrochem-
ical operations. Petrochemical operations include first
generation conventional refinery-associated production or
intermediates, including benzene-toluene-xylene (BTX), alkanes,
alkenes, alkynes, hydrogen and coke whose production is more
than 15% of the refinery throughput. It also includes second
generation petrochemical production such as cumene, phthalic
anhydride, alcohols, ketones, trimer and styrene.
Lube (D) - Includes topping, cracking and lube oil manufac-
turing operations. Lube oil feedstocks are recovered from
8-15-5
-------
the asphalt residues produced from the topping process.
Lube oils are separated from asphalt by solvent extraction.
This subcategory excludes formulating blended oils and
additives.
Integrated (E) - Includes topping, cracking, lube oil and
petrochemical operations.
4. Wastewater Characterization
The wastewaters generated by refining are diverse and complex,
representing a full range of organic and inorganic materials.
Some of these pollutants are biodegradable, some are removable
by physical-chemical treatment. Tables 8-15-1 and 8-15-2
contain raw wastewater characteristics from this industry.
5. Control and Treatment Technology
In-Plant Control - There are two types of in-plant practices
that reduce flow to the treatment plant:
A. Reuse practices involving the use of water from one
process in another process. Examples of this are: using
stripper bottoms for makeup to crude desalters; using blow-
down from high pressure boilers as feed to low pressure boilers;
and using treated effluent as makeup water wherever possible.
B. Recycle systems that use water more than once for the
same purpose. Example of recycle system is: the use of steam
condensate as boiler feedwater.
Another effective in-plant control is good housekeeping prac-
tices, including dry cleaning methods, to clean up oil spills,
minimizing leaks, and treating segregated waste streams such
as spent cleaning solutions.
Wastes generated by cleaning tanks and equipment during turn-
around should be collected and gradually bled to the sewer
after the necessary pretreatment steps.
Processes may be designed or modified to minimize waste load.
Examples include:
A. Substitution of improved catalysts.
B, Replacement of barometric condensers with surface con-
densers or air fan coolers.
8-15-6
-------
Table 8-15-1
Petroleum Refining Industry
Raw Wastewater Characteristics
00
1
M
L71
1
vl
Parameter (mg/1 )
BOD
TSS
TDS
COD
Oil & Grease
Phenols
Nitrogen -Ammonia
Chromium
Zinc
Cyanides
Su If ides
Phosphate
Topping
A
10-50
10-40
400-700
50-150
10-50*
0-200
.05-20
0-3*
.04-1.84*
0-.2
0-5
.1-10
Cracking
B
30-600*
10-100
400-700
150-400
15-300*
0-100
.5-200
0-6*
.04-1.84*
0-.2
0-400*
.1-10
Petrochemical
C
50-800*
50-200
400-700
300-600
20-250*
.5-50
4-300
0-5*
.04-1.84*
0-.2
0-200*
.1-10
Lubw
D
100-700*
80-300
400-700
400-700
40-400*
.1-25
1-120
0-2*
.04-1.84*
0-.2
0-40
.1-10
Integrated
E
100-800*
20-200
400-700
300-600
20-500*
.5-50
1-250
0-2*
.04-1.84*
0-.2
0-60*
.1-10
Note: *See Appendix 5 for parameters which may be inhibitory to
biological systems.
-------
TABLE 8-15-2
PETROLEUM REFINING INDUSTRY
WASTEWATER CHARACTERISTICS BASED ON PRODUCTION
oo
Parameter (kg/lOOOM )
Flow Range (gals per day)
Flow Type
BOD
TSS
T COD
CO
Oil & Grease
Phenols
Nitrogen Ammonia
Chromium
Sulfides
Topping
A
67MM
C
3.5
11.7
37.2
8.3
.034
1.2
.007
.055
Cracking
B
93MM
C
73
18
218
31.2
1*
28.3
.25
.95
Petrochemical
C
110MM
C
172
49
463
53
7.7
34.3
.24
.86
Lube
D
118MM
C
218
72
544
120
8.3
24
.046
.014
Integrated
E
235MM
C
198
58
329
75
3.8
20.5
.5
2
C Continuous
MM Million
-------
C. Cooling towers enable recycling of cooling water many
times, eliminating large volumes of once-through cooling water.
Many waste streams are routinely treated at the source, includ-
ing stripping of sour waters, neutralization and oxidation of
spent caustics, ballast water separation, and slop oil recovery.
Sour water stripping removes 85-99% of the sulfides before it
enters the sewer. Spent caustics are treated, and occasionally
products are extracted and sold. Slop oil or separator skimmings
are treated and reused.
Treatment Technology - End-of-pipe control technology relies
heavily upon the use of biological treatment methods preceded
by appropriate pretreatment to insure the proper conditions.
Table 8-15-3 shows removal efficiencies of several wastewater
treatment methods practiced by the industry.
8-15-9
-------
Table 8-15-3
Petroleum Industry Wastewater
Treatment Practices
Pollutant and Method Removal Efficiency, %
BOD
1. API Separator 5-40
2. Clarifier 30-60
3. Biological Treatment 40-99
4. Filter 40-70
5. Activated Carbon 70-98
COD
1. API Separator 5-30
2. Clarifier 20-50
3. Biological Treatment 30-95
4. Filter 20-55
5. Activated Carbon 70-94
TSS
1. API Separator 10-50
2. Clarifier 50-80
3. Biological Treatment 20-85
4. Filter 75-95
5. Activated Carbon 60-90
Oil
1. API Separator 60-99
2. Clarifier 60-95
3. Biological Treatment 50-99
4. Filter 65-95
5. Activated Carbon 70-95
Phenol
1. API Separator 0-50
2. Clarifier 0-50
3. Biological Treatment 60-99
4. Filter 5-20
5. Activated Carbon 90-100
Ammonia
1. Biological Treatment 0-99
Sulfide
1. Biological Treatment 70-100
8-15-10
-------
IRON AND STEEL
1. General Industry Description
Steel mills may range from comparatively small plants to completely
integrated steel complexes where great quantities of raw materials
and resources are brought together to ultimately produce steel.
Even the smallest of plants will generally represent a fair-sized
industrial complex. Because of the wide product range, the
operations vary significantly w.ithin each facility. Great quan-
tities of water are used, both for processing and for cooling
purposes. As a result, the iron and steel industry generates large
volumes of wastewater. This industrial category includes Standard
Industrial Classifications (SIC) 3312, 3313, 3315, 3316 and 3317-
2. Industrial Categorization
The iron and steel industry is composed of separate and distinct
processes with enough variability in both product and waste char-
acteristics to require categorization into more than one all-
encompassing unit operation. Accordingly, the industry can be
broadly subdivided into six major operational areas: coke making,
burden preparation, iron making, steel making, forming and finish-
ing and miscellaneous. The number and type of pollutant parameters
of significant yary with the operation being conducted and the
raw materials used. The waste volumes and waste loads also vary
with the operation. For the purposes of raw waste characterization
and delineation of pretreatment information, the industry is
further subcategorized primarily along operational lines, with
permutations where necessary, as shown in Table 8-16-1.
The code letters shown after the subcategories are used to iden-
tify them throughout this section. Process descriptions along
with the products and important measurable effluents associated
with each subcategory are provided below. The typical integrated
steel mill in the industry will embody several of these subcate-
gories and the discharges may be combined.
3. Process Descriptions
General
Five basic steps are involved in the production of steel in a
modern integrated steel mill:
1. Coal is converted into coke by either the by-product
process (A) or the beehive process (B). Coke fines generated
in these processes are screened out before the coke can be used
in the blast furnace.
2. Coke is combined with iron ore and limestone in a blast
8-16-1
-------
TABLE 8-16-1
IRON AND STEEL MANUFACTURING
Main Category
1. Coke Making
2. Burden Preparation
3. Iron Making
Subcategory
By-Product Coke
Beehive Coke
Sintering
Designation
(A)
(B)
(0
Blast Furnace Iron (D)
Blast Furnace - Ferromanganese(E)
4. Steel Making
5. Forming and Finishing
6. Miscellaneous
Basic Oxygen Furnace (F)
(Semi-wet Air Pollution
Control Methods)
Basic Oxygen Furnace (G)
(Wet Air Pollution
Control Methods)
Open Hearth Furnace (H)
Electric Arc Furnace (I)
(Semi Air Pollution
Control Methods)
Electric Arc Furnace (J)
(Wet Air Pollution
Control Methods)
Vacuum Degassing (K)
Continuous Casting (L)
Hot Forming - Primary (M)
Hot Forming - Section (N)
Hot Forming - Flat (0)
Pipe and Tubes (P)
Pickling-Sulfuric Acid- (Q)
Batch
Pickling-Hydrochloric Acid- (R)
Batch and Continuous
Cold Rolling (S)
Hot Coatings - Galvanizing (T)
Hot Coatings - Terne (U)
Misc. Runoffs - Storage (v)
Piles, Casting & Slagging
Cooling Water Slowdown (W)
Utility Slowdown (X)
Maintenance Department (Y)
Wastes
Central Treatment (Z)
8-16-2
-------
furnace to produce iron (D, E). Waste materials from the blast
furnace include sizeable quantities of fine dust which are high
in iron content,
3. Iron is converted into steel in either a basic oxygen
furnace (F, G), an open hearth furnace (H), or an electric furn-
ace (I, J), Further refinements include degassing (K) by sub-
jecting the steel to a high vacuum. Steel is cast either by
continuous casting (L) or in ingot molds. The slag generated
in the steel making processes is transported and subjected to a
slagging operation where the steel scrap is reclaimed and the
slag crushed into a saleable product.
Waste materials from the steel making processes include size-
able quantities of fine dust which are high in iron content.
4. Iron bearing waste fines from the blast furnace and
steel making processes are blended with limestone and coke fines
in a sintering operation (C) for the purpose of agglomerating
and recycling the fines back to the blast furnace. Processing
of steel plant wastes (burden preparation) by pelletizing or by
briquetting has also been proven on a pilot scale and several
such plants are due on line in the near future.
5. The final step includes forming and finishing operations.
Ingots are reduced to slabs or billets and ultimately to plates,
shapes, strips, etc. through the forming operations. The steel
finishing operations do little to alter the size or dimensions,
but impart desirable surface or mechanical characteristics to the
product.
A flow diagram of a typical steel mill is shown in Figure 8-16-1.
By-Product Coke (A)
Today the by-product process produces about 99 percent of a^Ll
metallurgical coke. Bituminous coal is heated in ovens out of
contact with air to drive off the volatile components. The
residue in the ovens is coke; the volatile components are re-
covered and processed to produce tar, light oils, and other
materials of potential value, including coke oven gas. Typical
products from the carbonization of coal are gas, tar, ammonia,
tar acids, hydrogen sulfide, light oil, coke and coke breeze.
The most significant liquid wastes are excess ammonia liquor,
final cooling water overflow, light oil recovery wastes and
indirect (Non-contact) cooling water. In addition, wastewaters
may result from coke wharf drainage, quench water overflow and
coal pile runoff. The final cooling water is a potential source
of highly toxic cyanogen compounds. Light oil recovery wastes
contain primarily phenol, cyanide, ammonia and oil. The effluent
8-16-3
-------
00
I
H1
CTi
I
DEGASSING
FIGURE 8-16-1
STEEL PRODUCT MANUFACTURING PROCESS
FLOW DIAGRAM
-------
from the quenching of coke, which is permitted to overflow to
the sewer in some plants, contains trace amounts of cyanide,
phenol and solids. Condensed steam and cooling water constitute
the bulk of wastewaters discharged to the sewer in this subcate-
gory.
Beehive Coke CB)
In this process for manufacturing coke, air is admitted to the
coking chamber in controlled amounts for the purpose of burning
the volatile products distilled from the coal to generate heat
for further distillation. The beehive produces only coke and
no other by-products are recovered. Water is used only for coke
quenching.
A properly controlled beehive oven has very little water dis-
charge. In some instances, an impoundment lagoon is provided
to collect the overflow water and settle out coke fines. Dis-
charges from this pond can contain phenol and cyanide, however
recycle to extinction with zero discharge is currently practiced
in some plants.
Sintering (C)
This plant has the primary function of agglomerating and recycl-
ing iron bearing waste fines back to the blast furnace. Sinter-
ing is achieved by blending the iron bearing components and
limestone with coke fines which act as a fuel. The mixture is
spread on a moving down draft grate and ignited. The down draft
keeps the coke burning and the bed is brought to fusion tempera-
ture. The hot sinter is crushed, cooled, sized and formed into
pellets and briquets.
Raw wastes from the sintering process emanate from the material
handling dust control equipment and the dust and volatized oil
in the process gases.
Most modern plants have fabric type dust collectors with no aque-
ous discharges. However, several plants utilize wet scrubbers
and generate wastewaters which contain significant concentrations
of suspended matter, oil, sulfide and fluoride. Usually aqueous dis-
charges are associated with the pelletizing or briquetting opera-
tions. However, there is potential for wastewater from wet'methods
of dust control.
Blast Furnace - Iron (D)
Virtually all iron made in the world today is produced in blast
furnaces which reduce iron ore to metallic iron. Iron ore,
limestone and coke are charged into the furnace. Coke is burned
to produce carbon monoxide which reacts with the ore to pro-
duce carbon dioxide and metallic iron. The major impurity of
most iron ores and coke is silica which is removed by the lime-
stone which combines with the silica to produce a molten mass
8-16-5
-------
called slag. As the molten iron leaves the blast furnace, the
floating slag is skimmed off. The auxiliary operations asso-
ciated with a blast furnace are raw material storage and handl-
ing, air compression and heating, gas cleaning, iron and slag
handling and dust handling.
The blast furnace has two basic water uses - cooling water and
gas washer water. Continuous circulation of cooling water is
required to prevent the furnace walls from burning through. The
principal wastewaters result from the gas cleaning operation.
These wastewaters contain significant concentrations of cyanide,
phenol, ammonia, sulfide and suspended solids. Phenol, cyanides,
and ammonia originate in the coke and are particularly high
if the coke has been quenched with wastewater or has not been com-
pletely coked. The suspended solids result from the fines in
the burden being carried out in the gas.
Blast Furnace - Ferromanganese (E)
The blast furnace charge consists of iron and manganese ores, lime-
stone and coke. The principal wastewaters are from the gas cleaning
operation and contain significant concentrations of cyanide,
phenol, ammonia, sulfide, manganese and suspended solids. Cyan-
ide formation, due to the reaction of carbon from the coke with
nitrogen from the blowing air, is particularly high at the
higher temperatures of a ferromanganese furnace as compared to
an iron furnace.
Basic Oxygen Furnace (F, G)
The raw materials for this steel making process are hot metal
(iron), scrap steel, limestone, burnt lime, fluorspar, dolomite
and iron ores. Alloying materials such as ferromanganese,
ferrosilicon, etc., may be used to finish steel to the required
specifications. The basic oxygen furnace uses pure oxygen to
refine the hot metal (iron) and all other metallics into steel
by oxidizing and removing the elements present such as silicon,
phosphorus, manganese, and carbon. Oxides such as silicon diox-
ide, manganese oxide, phosphorus pentoxide, and iron oxide are
fluidized in the slag which floats on the metal surface while
oxides of carbon are emitted as gas. The wastes from this pro-
cess are heat, airborne fluxes, slag, carbon monoxide and dioxide
gases and oxides of iron.
Basic oxygen furnaces are always equipped with gas cleaning sys-
tems for containing and cooling huge volumes of hot gases (1,650 c)
and submicron fumes released. Water is used to quench the off-
gases. Two main process types are used for gas cleaning: pre-
cipitators and venturi scrubbers. For venturi scrubbers, the
gases are quenched and saturated to 80 C, whereas for the pre-
cipitators the gases are cooled to about 250 C. If venturi
scrubbers are used, the majority of airborne contaminants are
mixed with water and discharged as effluents. Generally, water
8-16-6
-------
clarification equipment is provided for the treatment of this
effluent.
In addition to the fume collection cooling water system/ the
basic oxygen furnace has three main water systems:
1. Oxygen Lance Cooling Water System
2. Furnace Trunnion Ring Cooling Water System
3. Hood Cooling Water System
The oxygen lance cooling water system is either a "once-through"
or a "closed recirculation" system. The furnace trunnion ring
cooling is generally a "once-through" system with a discharge
differential temperature increase of about 20 C. The hood cool-
ing water system may be a recirculating type using induced draft
cooling towers with chemical treatment. If water of good quality
and sufficient quantity is available, "once-through" cooling
systems are sometimes employed.
Open Hearth Furnace (H)
Open hearth furnaces can utilize an all-scrap steel charge but
generally a 50-50 charge of hot metal and steel scrap is used.
The furnace front wall is provided with water cooled lined doors
for charging raw materials into the furnace. A plugged tap hole
at the base of the walJ, opposite to the doors is provided to drain
the finished molten steel into ladles. Fuel in the form of oil,
coke oven gas, natural gas, pitch, creosote, tar, etc., is burned
at one end of the furnace to provide heat for melting of scrap
and other process requirements.
The open hearth process has two plant water systems: The furnace
cooling water system and the fume collection water system. Furn-
ace cooling is a once-through system with heated aqueous dis-
charges of 17-22°C differential temperature. The fume collec-
tion systems are either wet high energy venturi scrubbers or
dry precipitators.
The aqueous discharges from precipitators are zero except for
any waste heat boiler blowdown. The discharges from the scrubbers
are wastewaters from the primary quenchers with concentrations
of fluoride, nitrates, suspended solids and zinc.
Electric Arc Furnace (I, J)
The electric arc furnace steel making process produces high qual-
ity and alloy steel in refractory lined cylindrical furnaces
utilizing a cold steel scrap charge and fluxes. Sometimes, a
lower grade of steel produced in the basic oxygen furnace or
the open hearth furnace is alloyed in the electric arc furnace.
8-16-7
-------
The heat for melting the scrap charge, fluxes, etc., is furnished
by passing an electric current through the scrap or steel bath
by means of three consumable cylindrical carbon electrodes
inserted through the furnace roof. The heat cycle generally
consists of charging, meltdown, molten metal period, oxidizing,
refining and tapping. Pure oxygen is sometimes lanced across
the bath to speed up the oxidation cycle. The waste products
from the process are smoke, slag, carbon monoxide and dioxide
gases and oxides of iron emitted as submicron fume. Zinc oxides
from galvanized scrap may be released depending upon the type
and quality of scrap.
The electric arc furnace has two main plant water systems: The
furnace cooling water system and the fume collection cooling^
water system. The former is generally a "once-through" system
but may be a "closed recirculation" system; the latter can
range from completely dry to semiwet to wet systems using precipi-
tators, bag houses, or high energy, venturi scrubbers. Semi-wet
systems are generally "once-through", with a temperature differ-
ential of 17-22 C in cooling waters. However, recycle to extinc-
tion with no discharge is also practiced. The wet high energy
venturi scrubber fume collection systems produce aqueous discharges
similar to the basic oxygen wastewater.
Vacuum Degassing (K)
In the vacuum degassing process, steel is further refined by
subjecting the ladle to a high vacuum in an enclosed refractory
lined chamber. Steam jet ejectors with barometric condensers
are employed to draw the vacuum. Certain alloys are added which
may be drawn into the gas stream. The system is purged with nitro-
gen to eliminate residual carbon monoxide.
The wastewater from this process contains suspended solids,
zinc, manganese, lead and nitrates.
Continuous Casting (L)
In the continuous casting process, billets, blooms, slabs and
other shapes are cast directly from the teeming hot metal, thus
eliminating the ingots, molds, soaking pits and stripping facili-
ties. Three water systems serve the casting machine: Mold
cooling, machine cooling, and spraying. Mold and machine cool-
ing are performed in closed recycle streams. Wastewaters result
from washing scale from the steel surface with spray water and
contain significant quantities of suspended matter and oil.
Hot Forming - Primary (M)
Hot forming defines the initial stages in forming useful products
from steel ingots by hot-rolling. The basic operation of a prim-
ary mill is the gradual cross-sectional reduction of a hot steel
ingot into blooms and slabs between the surfaces of two rotating
8-16-8
-------
steel rollers, and the progression of the ingot through the
space between the rolls. The hot steel ingots are transferred
to the primary mills for rolling from soaking pit furnaces which
consist of square, rectangular, or circular, fuel-fired refract-
ory lined pits. After delivery to the mill, the ingot is gen-
erally weighed on a scale and sent to the rolling mill stand.
During the rolling operation, cooling water is sprayed extensively
over the table and mill stand rolls. This water is discharged
to trenches beneath the rolling mill equipment. It is also
necessary to use high pressure (2000 psi) descaling water for
spray over the hot ingot to flush away iron oxide scales that
form on the hot ingot. The blooms are passed through hot-
scarfing machines after leaving the bloom shares to remove
defects from the surface of the bloom. Fume control is required
and water sprays carry the iron oxide wastes through a trench
under the mills to a collection system.
Hot Forming - Section (N)
Blooms from the primary mill are conveyed directly to the billet
mill without reheating. The billets are further processed to
produce material with small sections, such as tube rounds, bar
and rod, and special products. Modern billet mills utilize con-
tinuous mills which have alternate horizontal and vertical stands.
The continuous mill consists of a series of roll stands, arranged
one after the other so that the piece to be rolled enters the
first stand and travels through the mill, taking one pass in each
stand and emerging from the last set as a finished product.
Descaling water and cooling water are sprayed at the stands and
rolls with the discharge going to the trenches under the mills.
After the billet mills, the product is cut to the desired finish
piece length. The billets are cooled on cooling beds and pushed
into cradles, from which they can be loaded into cars for ship-
ment or transferred for further processing. Smaller quantities
of mill scale are generally generated in the hot forming-section
subcategory than in the primary rolling operation but the particle
size may be smaller and more difficult to settle out.
Hot Forming ~ Flat (0)
This subcategory embodies the operations associated with plate
mills, hot strip mills, and skelp mills. The basic operation
of a plate mill is the reduction of a heated slab to the weight
and dimensional limitations of plates. This is accomplished
by heating the slabs, descaling, rolling to plates, leveling
or flattening, cooling, and shearing to the desired size.
Descaling is completed on the delivery side of the mill as the
slab is passed through top and bottom high pressure hydraulic
sprays operating at 1,000 psi to 1,500 psi. About 4 percent
8-16-9
-------
of the spray water evaporates and the balance is discharged
through a trench under the mills to an iron oxide and water
collection system. During the rolling operation, cooling water
is sprayed externally over the table and mill stand rolls.
The basic operation of a hot strip mill is the reduction of slab
to flat strip steel in thicknesses of 0.04 in. to 1.25 in.,
widths of 24 in. to 96 in., and lengths of up to 2,000 ft.
Principal water uses include descaling water sprays and cool-
ing water.
Skelp is a hot-rolled strip used to make butt-weld pipe or tube.
Skelp is rolled from a heated bloom and has a width which corre-
sponds to the circumference of the pipe and a gauge which corre-
sponds to the thickness of the wall. Descaling water, cooling
water, and water-soluble oil sprays accompany the rolling opera-
tion.
Pipe and Tubes (P)
Typical steel tubular products are standard pipe, conduit pipe,
line pipe, pressure pipe, structural pipe, oil-country tubular
goods, pressure tubes, mechanical tubes, and stainless steel
pipe and tubes. Butt-welded pipe or tube is made from a hot-
rolled strip. By heating this skelp to the welding tempera-
ture and drawing it through a die or roll pass, it is bent into
cylindrical shape and its edges pressed firmly together into
a butt-weld, thus forming a pipe. Seamless tubular products
are made either by "piercing" or by "cupping^" In the former
process, a solid round bar or billet is heated, pierced and
then shaped to the desired diameter and wall thickness. In
cupping, a circular sheet or plate is forced by successive
operations through several pairs of conical dies until the
plate takes the form of a tube or cylinder with one end closed.
Electric-resistance-welded tubing (ERW) is made from strip sheet
or plate. The steps in the manufacture of ERW are: forming,
welding, sizing, cutting, and finishing. Plates are converted
into pipes by the electric-weld process by shearing, planing,
crimping, bending, welding, expanding, and finishing.
Significant pollutants in the wastewaters resulting from this
subcategory include suspended solids and oil and grease. Waste-
waters originate from contact cooling waters such as roll spray
cooling waters and cooling bed or spray quench waters. Suspended
solids can be traced to the scale which is flushed off the pipe
surface by the roll cooling spray waters. Oil and grease
originate in the hydraulic and lubricating systems.
Pickling-Sulfuric Acid-Batch (Q) and Pickling-Hydrochloric
Acid-Batch and Continuous (R)
Pickling is the chemical removal of surface oxides (scale) from
metal by immersion in a heated solution. Carbon steel pickling
8-16-10
-------
is almost universally accomplished by using either surfuric
acid CQ1 or hydrochloric acid (R). The acid conditions vary
with the type of material to be pickled. In addition, bath
temperature, use of inhibitors, and source of agitation are
also varied depending on the material to be pickled. Pickling
is done by either continuous strip or batch type operations.
Continuous strip pickling lines use horizontal pickling tanks.
Large, open tanks of a wide range of sizes are used for batch
type pickling, principally for rod coils, bars, billets, sheet,
strip, wire, and tubing. Pickling is also applicable to forg-
ings, castings, structural parts, and other items.
In continuous pickling, fresh acid solution is added to the
last tank section and cascades through the tanks to an overflow
located in the first section. Acid solution flow is opposite
to the direction of the strip travel. In batch type pickling,
the tanks are generally rubber lined and brick sheathed and
hold a large volume of heated acid solution. Sulfuric acid
is most often used for this purpose. After a certain iron build-
up due to iron scale removal, the batch acid solution is con-
sidered spent and umped. The pickling is followed by the rinse
operation which may vary from a one-step dunk to more sophisticated
multi-stage rinsing. The primary purpose of rinsing is to
remove the contaminants prior to the next sequence in the pro-
cess. The first rinse removes the bulk of contaminants. The
next rinse section can be either dunk rinse or spray- The
water from this section is used to replenish the first-stage
rinse section. The last stage uses clean, fresh water as the
washing medium to insure a clean product. It may be possible
to use the contaminated rinse water as input water to the fume
scrubber, prior to its final disposition as pickle recycling
system makeup water.
Most continuous strip pickling lines employ the traditional
approach to rinsing: flooding the strip with hundreds of gallons
of waters per minute to wash away the few gallons of acid that
may be dragged out of the pickling tanks. Multi-stage spray
rinsing systems can easily be incorporated into new continuous
strip pickling lines, and they can be installed in existing
lines in place of the present rinsing sections.
Acid fumes are prevalent in the pickling process and must be
removed in order to provide a good working environment. To
remove the acid from the exhaust stream, washing or filtration
methods may be applied. In scrubbers, the acid droplets are
contacted with water, trapped, and then flushed away. Acid mist
filters use specially designed synthetic fibers in a filter box
which is installed in the discharge end of an exhaust system.
This system releases water vapor to the atmosphere while it
collects the acid droplets and returns them to the pickle tank.
The acid mist filter controls air pollution and simultaneously
recovers acid for reuse.
8-16-11
-------
Wastewater/s. in the pickling^sulfuric acid-batch subcategory (Q)
originate in either of two forms: as spent solutions of concen-
trated waste pickle liquor containing iron and sulfuric acid;
or as dilute solutions resulting from dunk or spray rinsing of
pickled product. The significant pollutants in the pickling-
hydrochloric acid-batch and continuous subcategory (R) include
suspended solids, total iron, ferrous iron, dissolved iron and
pH.
Cold Rolling (S)
In cold rolling, cooled hot strip mill product is passed through a
pair of rolls for the purpose of reducing its thickness, producing a
smooth dense surface, and developing controlled mechanical proper-
ties in the metal. Cold reduction is a special form of cold
rolling in which the thickness of the starting material is
reduced by relatively large amounts in each pass through the
rolls. In tempering, the thickness of the material is reduced
only a few percent to impart the desired mechanical properties
and surface characteristics to the final product. During rolling,
the steel becomes quite hard and unsuitable for most uses. As
a result, the strip must undergo an annealing (heating) opera-
tion to return its ductility and to effect other changes in
mechanical properties suitable for its intended use. This is
done in either a batch or continuous annealing operation.
Wastewaters from this subcategory originate when water, oil,
oil-in-water emulsions, oil-water-detergent solutions or combina-
tions of any of these rolling solutions, used for cooling or
lubricating the rolls, are dumped. Suspended solids and oil and
grease are the important pollutants.
Hot Coatings-Galvanizing (T) and Hot Coatings-Terne (U)
Coating is the application of a layer of one substance to com-
pletely cover another. In the iron and steel industry, coatings
are applied for a variety of reasons. Most often, a relatively
thin layer of a metallic element such as zinc, chromium or
aluminum is applied to carbon steel, imparting such desirable
qualities as resistance to corrosion, safety from contamination,
or decorative appearance. In addition to metallic coatings,
non-metals, simple and complex organic compounds, miscellaneous
inorganic materials such as vitreous enamel, and metallic
powders in silicate paints are also used as coating materials.
All methods of applying coatings to steel surfaces require
careful surface preparation which is the primary and most import-
ant step in the process. Commonly used for this purpose are al-
kaline or solvent cleaning for grease removal, acid pickling
for removing scale or rust, and physical desurfacing using
abrasives or brushes. Following surface preparation, metallic
coatings may be applied by one of the following processes:
hot dip process, electroplating, metal spraying, metal cementa-
tion, fuse welding, metal cladding.
8-16-12
-------
Hot dipped coating using steel baths of molten metal is prac-
ticed as a batch^dip operation. In hot coatings-galvanizing (T) ,
the coated products are withdrawn from the bath, subjected to
drying with a warm air blast, or chemically treated with ammon-
ium chloride, sulfur dioxide, chromate or phosphate solutions to
produce special galvanized finishes and surface characteristics.
Terne is an inexpensive, corrosion-resistant, hot-dipped coating
(U) consisting of lead and tin. A major portion of all terne
coated materials is used in the automobile industry to manu-
facture gasoline tanks, automotive mufflers, oil pans, air
cleaners, and radiator parts. Batch and continuous terne coat-
ing operations both exist, though the continuous process is by
far the larger portion of the market.
Wastewaters in the hot coating-galvanizing (T) subcategory
result from cleaning operations, chemical treatment, and rinses
applied to the product before or after coating as well as batch
discharges from the various solutions and baths. Suspended
solids, oil and grease, zinc, chromium and pH are the principal
pollutants. Wastewaters in the hot coating-terne subcategory
originate from similar sources and contain suspended solids, oil
and grease, lead, tin, and pH.
Subcategories V-z
There are no iron and steel manufacturing processes associated
with subcategories V-Z, as this miscellaneous category covers
ancillary operations within a mill. Wastewaters resulting from
these operations are highly variable in both quality and quantity.
4. Wastewater Characteristics
The characteristics of process wastewaters are shown in Table
8-16-2. In addition to the pollutants listed in the table,
thermal discharges may also be generated.
The steel industry operates throughout the year and generates
wastewaters over a 24-hour day. Wastewater volume and charac-
teristics are subject to hourly variations. The process waste-
waters are generally treated on site before disposal.
Wastewaters are subject to wide variations in flow within in-
dividual subcategories. This is largely due to the diversity
in the plant cooling water systems and the fume collection and
cooling systems.
The BOD in the wastewaters of the steel industry is mostly
due to the coke manufacturing processes. However, cold rolling
and blast furnace wastewaters will also'contribute some BOD.
Coking process waters are generally, amenable to"biological
treatment only if they comprise less than 25 percent of the
total wastewater.
8-16-13
-------
TABLE 8-16-2
IRON AND STEEL MANUFACTURING
RAW WASTEWATER CHARACTERISTICS
Parameter
Flow Range
(1/kkg)
Flow Type
BOD52
SS
PH
Airmonia
Oil and Grease
Cyanide*
Phenol
Sulfide
Fluoride
Manganese
Nitrate
Zinc
Lead
By-Product
Coke
A
171/19182
A
12-1550*
23-421
39-7330*
2. -240*
7.7-110*
6.1-910
4.2-629*
Beehive Sintering Blast
Coke Furnace
Fe
BCD
513/2040 434/1420 8050/
22500
B C C
0-3
29-722 4340- 307-
19500 1720
0-0.33 1.-12.
457-504
0-1
0-.01
64. -188* 0-40
0-.6 0-2
Blast BOF BOF Open Electric
Furnace (Semiwet) (Wet) Hearth Arc
Fe - Mn Furnace Furnace
(Semiwet)
E F G H I
32,200 542/3040 1080/ 2290/ 1.01/406
4250 2530
C C C C C
5,000 321-396 180- 388- 77-863
5330 3880
141
23.6*
0.13
0-2. 0-11 16-20
833*
20. -33.*
2-880* 0-13*
Electric Vacuum
Arc Degassing
Furnace
(Wet)
J K
751/1250 813/3750
C C
2160- 23-70
42800
10-15
5-13*
3. -25*
405*- 2*-8*
5637*
.4*-!*
Continuous
Casting
L
6172/17100
C
7. -74.
20.5-22.0
NOTE: 1. 1/kkg of product produced (lower limit/upper limit)
2. All concentrations represent net raw wastes and are in mg/1 except as noted.
B. Batch Process
C. Continuous Process
* See Appendix 5 for parameters which may be inhibitory to biological systems.
# With acclimation higher levels can be tolerated.
-------
TABLE 8-16-2(continued)
IRON AND STEEL MANUFACTURING
RAW WASTEWATER CHARACTERISTICS
Parameter
Flow Range1
(Vkkg)
Flow Type
BOD5 («>9/1)2
SS
pH
Ammonia
f Oil and Grease
H Cyanide!
Ol
Phenol
Sul fide
Fluoride
Manganese
Nitrate
Zinc
Lead
Total Iron
Sul fates
Chlorides
Hot Hot Hot Pipe Pickling Pickling Cold Hot Hot Misc. Cooling Utility Maint. Central
Forming Forming Forming and Sulfuric Hydrochl. Rolling Coatings Coatings Runoffs Water Slowdown Dept. Treatment
Primary Section Flat Tubes Acid- Acid- Galvani- Terne Slowdown Wastes
Batch Batch & zing
Contin.
MNOFQRSTU VW XYZ
330/6210 7980/ 18.900/ 2150/ 23/1630 12/4720 73/2135 5,146 2150/ Variable Variable Variable Variable Variable
138,200 35,200 53,300 9150
B
15
4-91 12-125 6-57 27-103 21-159 90-900 98 8-48 412 Present Present Present
7.6 6-9 6-9
2-14 0-14 2-10 0-61* 54*- 19 73* Present
41,140*
3.2*
14.5* Present
0.20
42*- 134*-
7,900* 117,000*
105- 592-890
26,000*
3-
200,000*
NOTE: 1. 1/kkg of product produced (lower limit/upper limit)
2. All concentrations represent net raw wastes and are in mg/1 except as noted.
B, Batch Process
* See Appendix 5 for parameters which may be inhibitory to biological systems.
# With acclimation higher levels can be tolerated.
-------
5. Control and Treatment Technology
In-Plant Control
Significant in-plant control of both waste quantity and quality
is possible for some important subcategories of the iron and
steel manufacturing industry. In by-product coke making (A)
wastewaters are generated by the coking process and there also
is usually a wastewater discharge from the coke quenching
operation. The wastewaters from the by-product coke making
operation (A) are highly contaminated and require intensive
treatment. Wastewater from coke quenching can be reduced by
dry coke quenching or simply by routing the wharf drains to the
quench tower as make-up water and not allowing any overflow from
the quench tower. Zero liquid discharge from modern coke plants
can be achieved by evaporation of all liquid to dryness since
the pollutants are mostly volatile except approximately 1%
dissolved solids (chlorides, etc.), but this would be accompanied
by potential air pollution problems. The effluent gases from
less than optimum incineration of the wastewater can be expected
to contain high concentrations of nitrogen oxides, sulfur oxides,
and some particulate matter.
Liquid discharges from the blast furnace subcategories (D,E)
can be significantly reduced by recycling the gas cleaning and
cooling water. Modern blast furnace practice has shown that this
water could be put through settling chambers to remove the sus-
pended solids and over a cooling tower to remove the heat.
The liquid discharge exclusive of non-contact cooling water for
all of the steel making processes - basic oxygen (F,G), open
hearth (H), and electric furnace (I,J) - results from the gas
cleaning operations. Although the technology for dry gas
cleaning lags behind the requirements for gas cleanliness,
reductions in flow or pollutant loads from these subcategories
are still feasible by the use of recycle systems and closeup of
semi-wet systems.
In the hot forming-primary subcategory (M), an important control
measure relating to all contact cooling, deseraling and scarfing
wastewaters is the periodic cleaning of scale pits to remove
buildup of mill scale which otherwise will wash through. The
same measure is also applicable to the hot-forming-section (N)
and hot forming-flat (0) subcategories. Complete recycle with
no blowdown, makeup as needed, and cooling tower or pond cool-
ing for hot mills will result in zero discharge of wastewaters
from the pipe and tubes subcategory (P). While this is practiced
in some mills it may not be accomplished under all circumstances.
In the pickling-sulfuric acid-batch subcategory (Q), on site
recovery of acid from concentrates, rinses, and fume scrubber
effluents, and the recovery of iron as ferrous hepthahydrate
8-16-16
-------
crystals can eliminate aqueous discharges. However, high
initial capital costs are involved which may be eventually
balanced by recovery of usable products. In hydrochloric
acid pickling (R), reuse of all acid rinse waters to make
up fresh batches or pickle liquor is possible. In cold roll-
ing (S), recycle of rolling solutions and use of treated
wastewaters on cold rolling lines can significantly reduce
discharges. In hot coatings (T, U), control of wastewater
volumes through counter-current rinses and by use of fume
hood scrubber recycle systems, and special attention to main-
tenance of equipment designed to reduce loss of solution are
effective means for reducing discharge loads.
Treatment Technology
The iron and steel manufacturing industry utilizes a broad range
of treatment technology in control of its effluents. Table
8-16-3 presents a brief summary of the treatment practices
employed in each subcategory, and the pollutant removals achiev-
able with each treatment process.
8-16-17
-------
TABLE 8-16-3
IRON AND STEEL MANUFACTURING
WASTEWATER TREATMENT PRACTICES
REMOVAL EFFICIENCIES, PERCENT
Pollutant and Method
Blast Blast
By-Product Beehive Furnace Furnace
Coke Coke Sintering Fe Fe-Mn
A B C D E
Electric
Open Arc
BOF BOF Hearth Furnace
(Semi-wet) (wet) Furnace (Semi-wet)
F G H I
Electric
Arc
Furnace Vacuum Continuous
(wet) Degassing Casting
0 K L
Suspended Solids
1. Chemical Coagulation &
Thickening
2. Sedimentation &
Filtration 74
BOD
1. Activated Sludge &
Clarification 98
2. Settling 48
03
,1, Ammonia
cri ~~
M 1. Solvent Recovery, Ammonia
03 Stripping & Settling 93
2. Settling
Phenol
1. Activated sludge or
Solvent Extraction 99
Nitrate
1. Bio-Denitrification
99
80
40
99
91
99
97
25
90
98
100
99
97
97
91
94
Zinc
1. Chemical Coagulation and
Thickening
2. Settling and Filtration
Fluoride
1. Coagulation and
Sedimentation
70
42
99
60
10
-------
TABLE 8-16-3 (continued)
IRON AND STEEL MANUFACTURING
WASTEWATER TREATMENT PRACTICES
REMOVAL EFFICIENCIES, PERCENT
Pollutant and Method
Suspended Solids
1. Clarification,
Chemical Treatment
& Filtration
2. Sedimentation
Oil & Grease
1. Primary and
Hot
Forming
Primary
M
99
Hot
Forming
Section
N
99
Hot Pipe
Forming and
Fl at Tubes
0 P
99 99
80
Pickling
Sulfuric
Acid-
Batch
Q
Pickling Cold
Hydrochl. Rolling
Acid-
Batch &
Con tin.
R S
99
Hot Hot
Coatings Coatings
Galvani- Terne
zing
T U
80
Fugitive Cooling Utility Maint. Central
Runoffs Water Slowdown Dept. Treatment
Slowdown Wastes
V W X Y Z
Secondary
Clarification,
including
Skimming
2. Air Flotation,Chemical
Treatment, &
Clarification
85
85
85
80
90
85
-------
NONFERROUS METALS
1. General Industry Description
The Nonferrous Metals Industry concerns itself with the smelting
and refining of nonferrous metals including aluminum, copper,
lead and zinc. This description does not include the mining of
the materials or manufacturing of final products based on these
metals»
In general, wastes from this industry are low in BOD and COD,
but may be high in dissolved and suspended solids.
This industry includes Standard Industrial Classifications
(SIC) 2819, 333 and 334.
2. Industrial Categorization
Subcategory Designation
Bauxite Refining A
Primary Aluminum Smelting B
Secondary Aluminum Smelting C
Primary Copper Smelting D
Primary Copper Refining E
Secondary Copper F
Primary Lead G
Primary Zinc H
3. Process Description
Bauxite Refining (A)
Bauxite is the principal ore of aluminum and the only one used
commercially in the United States. Bauxite is composed of
hydrated aluminum oxide and impurities such as iron oxide, aluminum
silicate, titanium dioxide, quartz, and compounds of phosphorus
and vanadium. The process for refining bauxite is the Bayer
process, in which the impure alumina is dissolved in a hot strong
alkali solution to form sodium aluminate. The solution is diluted
and cooled whereby sodium aluminate hydrolyzes and precipitates
and is then filtered out of solution, and calcined to alumina.
Figure 8-17-1 is a flow diagram for the Bayer Process.
The major waste stream is "Red Mud", which contains the impurities
rejected from the bauxite. The red mud consists of 17-20% solids.
Other waste streams include air scrubber effluents, barometric
condenser effluents, cooling water, chemical cleaning wastes, and
spills and leaks.
8-17-1
-------
Bauxite
Reconcentrated Caustic Liquor
f Washing precipitates
Condensate - To J Boiler feed water
^ Dilution Green Liquor
Steam
To
Mud Lake
Calcined Alumina
Product
FIGURE 8-17-1
BAUXITE REFINING (A)
GENERALIZED DIAGRAM OF THE BAYER PROCESS
NONFERROUS METALS INDUSTRY
8-17-2
-------
Primary Aluminum Smelting (B)
The primary aluminum process is defined as the reduction of
purified aluminum oxide (alumina) to produce aluminum metal by
the Hall-Heroult process and electrolytic process. A process flow
diagram is shown in Figure 8-17-2. The reduction of alumina to
produce aluminum metal is carried out in electrolytic cells, or
pots, connected in series to form a potline. The facility con-
taining a number of potlines is referred to as the potroom. The
electrolysis takes place in a molten bath composed of cryolite,
a double fluoride of sodium and aluminum. Alumina is added to
the bath periodically. As electrolysis proceeds, aluminum is
deposited at the cathode (as a liquid) and oxygen is evolved at
the carbon anode. The oxygen reacts with the carbon anode to
produce carbon monoxide and carbon dioxide. The anode is con-
sumed and must be replaced periodically. The liquid aluminum
produced is tapped periodically, and the metal is cast in a
separate casthouse facility. The molten metal is degassed before
casting by bubbling chlorine or a mixed gas through the melt.
The chlorine degassing procedure produces a fume which must be
scrubbed for air pollution control, producing a waste stream.
The continuous evolution of gases at the anode described above
yields a large volume of fume. This gas stream also has to be
scrubbed, producing a waste stream.
The cathode of the aluminum reduction cell is a carbon liner
on which the pool of aluminum rests. During service the cathode
becomes impregnated with bath materials and must be replaced.
Water contacting spent electrodes has a significant fluoride
content due to leaching action, and may represent a source of
contamination.
Other waste streams from this process are cooling waters used
in casting, rectifiers and fabrication, and boiler blowdown.
Secondary Aluminum Smelting (C)
The secondary aluminum smelting subcategory is defined as that
segment of the industry which recovers, processes and remelts
aluminum scrap to produce metallic aluminum or an aluminum alloy.
Figure 8-17-3 is a flow diagram for this process. Aluminum scrap
is prepared for smelting and refining in a variety of ways.
Some plants employ wet processing techniques to wash the feed,
and carry away fluxing salts and chemicals, thus generating a
wastewater.
The scrap metal is then charged to the furnace where flux, and
alloying agents are added. The molten metal is mixed in the
furnace to insure uniform composition of the material. Magnesium
impurities are removed in the furnace by a process called "demagging"
which is the addition of chlorinating agents or aluminum fluoride
to produce magnesium compounds that can be scraped off the top
of the melt. This operation produces fumes, which if treated
with wet scrubbers, produces a waste stream.
8-17-3
-------
Petroleum Coke
Pitch
ANODE PASTE
HOT - BLENDING
Anthracite Pitch
| Soderberg
. anode
Briquettes
-Electrical Supply (Direct Current)
"Alumina
'Cryolite
Calcium Fluoride
Aluminum Fluoride
Air
FUSED SALT
ELECTROLYTIC
CELL
MOLTEN ALUMINUM
To degassing and
casting
Aluminum (pig,
billet, ingot, rod)
Dry-Process Wet-Scrubber
Solids returned liquor to
to cell treatment
Spent Potliners (to cryolite recovery
or disposal)
FIGURE 8-17-2
PRIMARY ALUMINUM SMELTING(B)
PROCESS DIAGRAM FOR THE ELECTROLYTIC PRODUCTION OF ALUMINUM
NONFERROUS METALS INDUSTRY
8-17-4
-------
Al Scrap Producer
Cu
00
I
I
01
Collector
Etc
Packaging,.^_
ahlpment
H o+
dldolved + H.O 4- ..It.
salt!
exhaust
ants
umei
Air Pollution Control
(scrubber)
gassing
'^
E times
.magging
-H.O
Smelting
Addition of
alloying
agent
Addition of
fluxing
agents
f
1
1 fuaies
^ Scrap charged
Into
furnace fo revel 1
t 1 t|
j, N2> or Cl, N, mixture Zn SI. Cu.
NaCit Kd,
FIGURE 8-17-3
SECONDARY ALUMINUM PROCESS (C)
NONFERROUS METALS INDUSTRY
-------
Primary Copper Smelting (D)
The primary copper industry manufacturers copper from its ore.
Copper concentrates are fed to the primary smelter, which
produces blister copper after roasting, smelting and converting.
The blister copper is then sent to the refinery (E) for puri-
fication.
Roasting, the first operation, reduces the content of sulfur as
well as other impurities contained in the feed, to produce calcine
(roasted concentrate). The calcine along with copper-bearing
scrap, low-grade ores, and recycled slag, is smelted in either
a reverberatory or electric furnace. The main objective of this
treatment is to collect the copper in a molten copper-iron-sulfide
material called matte, suitable for treatment in converters. The
slag is wasted and the molten matte is charged to converters.
In the converter air streams are blown through the molten material
to oxidize and remove iron and sulfur impurities as converter slag
and to form an impure form of copper called blister copper.
Furnace slag may be wasted or granulated and sold. Some smelters
use a high velocity jet of water to granulate slag. Wastewaters
contain dissolved solids, arsenic, and metals. Additional waste
streams are generated by wet air scrubbers and cooling water.
Primary Copper Refining (E)
Fire refining is a pyro-metallurgical operation where blister
copper is further refined as either fire-refined copper or anode
copper, which is used in subsequent electrolytic refining. Anode
furnace refining removes large amounts of impurities so that the
anodes produced will be acceptable for electrolysis. The operation
is carried out by introducing air into the furnace beneath the
molten metal surface. After the impurities are oxidized and the
slag is removed, the copper is either cast into anodes for further
refining or cast into shapes and sold.
In the electrolytic refining process, copper is separated from
impurities by electrolytic dissolution at the amode and deposition
as the pure metal at the cathode to produce a very high purity
product called cathode copper. By-products such as gold and silver
which were the contaminants, are collected as "slimes" and sub-
sequently recovered. A process flow diagram is shown in Figure 8-17-4,
Sources of wastewater include disposal of spent electrolytic baths,
slimes recovery, cooling waters, air scrubbers, washdowns and storm-
water runoff. Pollutants include dissolved and suspended solids,
metals, arsenic and oil and grease.
8-17-6
-------
Blister
copper
Electrolytic
cell;
Stea
Acid ^f1!
Storage 1 r
Ht
Exch
i
Acid
Storage
3
Slime
m to recovery
[| Heated electrolyte
sat T
Condensate
Liberator
cells |
T
Evaporator
t
C*»nfrifnCTp
-^
Copper
Product
Decopperized
electrolyte
FIGURE .8-17-4
ELECTROLYTIC COPPER REFINING (E)
NONFERROUS METALS INDUSTRY
8-17-7
-------
Secondary Copper (F)
The secondary copper industry consists of operations that recover
copper metal and copper alloys from copper-bearing scrap metal
and smelting residues (e.g. spills, slags, skimming, etc.).
Scrap metal also includes brass and bronze, which are used to
produce copper alloys. The processes in the secondary copper
industry are "essentially the same as those for primary copper.
However, some variations are used in preparation of the scrap.
Water is used occasionally in hammer mills used to strip insulation
from copper wire, and in wet milling and concentrating copper
from copper slags. Water is also used in air cleaning systems.
Smelting, converting and refining operations were discussed in (D)
and (E) above.
Primary Lead (G)
Concentrated lead ore is blended with a flux (a substance which
promotes fusion), pelletized and then sintered. Sintering on a
sintering machine (a traveling grate furnace) removes sulfur
by oxidation and other impurities such as arsenic, antimony, and
cadmium by volatilization. The sintered product is crushed. Dusts
generated by the sizing operation may be captured by wet scrubbers
generating a wastewater. Figure 8-17-5 is a flow diagram for lead
smelting and refining.
The sinter is fed to the blast furnace whereby a combination of
heat and reducing gases it separates into two phases: molten
metal and slag. The products of the blast furnace are as follows:
a. Lead bullion which contains quantitites of copper, arsenic,
antimony, or bismuth which must be removed by further
processing. It may contain precious metals which are worth
recovering.
b. Slag, which consists of iron, calcium and magnesium silicates,
arsenic and antimony. Granulating the slag may generate a
wastewater (discussed in D).
c. Matte and speiss - The matte phase consists of a liquid
layer of copper and iron sulfides and precious metals. If
considerable arsenic is present, speiss is formed. These
are sent to outside processors for further treatment.
The lead bullion is subject to dressing, the first step of the
refining process, which consists of removing copper by adjusting
the temperature of the melt so that copper separates out of
solution.
The next refining step is called softening, which removes
antimony. Softening is accomplished in a furnace or by treatment
of bullion with a sodium hydroxide sodium nitrate mixture.
8-17-8
-------
SMI
Lead Coacantrataa
1
Flu» . Char
Prepar
r.. , ,
Recycle
Under* lie
I i
L "I
SECTION
UFIN
Coke _ §u
I*
atlon Sollda
i ft.ek
S02 '"' Duat Plant J
tar >u_e ~* Collection
Recycle
to Sinter
t
at Slac .. Slaii . ~~. 1 1 _ To
. >. Furnace Granulation | Waate
Partial 1
Recycle of ' Sett
Refinery
Droaa
Lead I
1 * | lat and
J f
I Slag Water
ler | *
Slag Zinc Fu.ln. "~ " "ih°U"
ulllon Furnace .. Slag to Waate
[ 1 t
2nd Copper By-Product
Sulfur ^Droa. Kettle. Dro<§ Kev.r.er.tory .- copper Matt, and Sp. la.
«' hs
, . ... » fi-pp-r <: It.r
r-lLX^ ^-Coke. N.2COV Silica ^L.ad O.id.
nlng _Araenlcal 4 _ Hard Lead a-fi.i.,. . .... ,,
,.c. Antl«,nl.l- Furnace "^ ~ ^^
^p" Slag to Charge Preparation (By-Product)
t
Deailve
^__^ X
ERY
SECTION
Zinc p Deallver
2
Vac
Ca.Hg p. Deblamu
Ket
Zinc to Deatlverlting
. Lead , .... i »IT
* f '
juimi ?rttt ! | |
^ Secondary Silver Ski mi '
i PbO(LltharM)
1 *-] r1 ' 1 to B.F.
ir<"t Ski ma r Hou.rd
Preaa
cum Cl. Caa,
nclng Oxldliing Flux,
Charcoal
rhtrln* .. Bllmuth ., (n,m,,th Mrfal
tie uro«»
HaOH Refining r Removal, Tracea of Zn, Sb, and Aa
NaNO, Kettle (Cauatlc Drosi to Charge Preparation)
\
Refined Lead
FIGURE, .8^17-5
GENERALIZED FLOW SHEET OF A LEAD
SMELTER AND REFINERY (G)
NONFERROUS METALS INDUSTRY
8-17-9
-------
The softened lead bullion is then fire refined to separate
gold, silver and bismuth. The final refining operation consists
of adding caustic -soda to remove calcium and magnesium from the
metal.
Wastewaters are produced from noncontact cooling, gas scrubbing,
and direct cooling and cleaning water from process operations.
Pollutants include dissolved solids and metals.
Primary Zinc (H)
There are two types of zinc producing processes used in this
country: the pyrolytic process and the electrolytic process
,shown in Figures 8-17-6 and 8-17-7- Both processes begin withfthe
\roasting operation in order to remove sulfur and other impurities
and take, place in a furnace. In the pyrolytic process,-the
operations include: sintering, briquetting, reduction, refining,
and cadmium recovery.
In the electrolytic process the operations include: reduction
and cadmium recovery.
Sintering and briquetting are preparation steps which produce an
acceptable feed to the furnace. Refining consists of removing
impurities such as lead and iron. Since there is a large quantity
of cadmium in zinc ore, it is recovered as a by product from the
air pollution control equipment (bag houses) in the roasting and
sintering operations.
Wastewaters from zinc production come from non-contact cooling
water, wet air scrubbers, contact cooling waters, spent process
liquors, boiler blowdowns, and spills and leaks.
4. Wastewater Characterization
Tables 8-17-1 and 8-17-2 contain wastewater .characteristics for
this industry.
-5. Control and Treatment Technology
In-Plant Control
Wet scrubbing water may be eliminated by substituting dry air
cleaning techniques, or may be minimized by recycling scrubber
water.
Bauxite Refining (A)
The major waste from this subcategory is "red mud," and the only
treatment for this waste is impoundment. Due to the large volume
of red mud produced compared to the other wastes generated, the
most practical treatment of the other wastes is to impound them
with the red mud.
8-17-10
-------
ZINC CONCENTRATES
i
Storage, drying, blending
Secondary or
oxidic materials
I
Gases to
atmosphere
Dust collection ]
Scrubbing ( Acid
Mercury recovery | Plant
Fumes, dusts,
residues
T
Calcine
Sulfuric
acid
1
> Prepai
i
^ Blue
r Moisture
Oxides
-Jtion , v ,
Coke
Sand
- r"- .
^ -* * ' "-| Kecycie
Return
sinter
Metallics ,j
^ r
fnlff*
Electrothermic
reductici.
1
Bri<]MetMng ^
1
Vertical retor
reduction
\ /
jowder r - -* -\ Car
Gases tc
dust atmosphei
| |
Dust
Collection
_J |
Cadmium plant
t Prifllj ''lay
and binder
t
Stack
1
bon monoxide |
SLAB ZINC
lower grades
ZINC OXIDE
.Liquation
Oxidation
Plant use
American
process
SLAB ZINC
special
high grade
ZINC OXIDE
Refining
(redistillation)
Sla
Residue trc
> ,
)
? *
ard r
\
/
;atm
ent
\
x
^
French process
Ferrosilicon
High zinc
concentrate
recycled
Reclaimed coke
recycled
Lead-silver cone.
to lead plant
FIGURE 8-17-6
PYROLYTIC ZINC PROCESSING(H)
GENERALIZED FLOWSHEETS OF PYROLYTIC ZINC PLANTS
NONFERROUS METALS INDUSTRY
8-17-11
-------
Granu
"1
C
oke-i
t
>
-Br
r
i-q
nets
pSint
Graphite electrodes
Carbon monoxide
gas burne
Rotary
tV* distributor
Gamma ray source
5Gas washer
Zinc vapor
carbon
and monoxides
,Vapor ring
Carbon monoxide Batch fed_^
to dross ±
vacuum pumps *.
Charge level
detector^ ,
Blue powder
slurry
to ponds
Liquid zinc
Tap hole
Cooling we'll
Condenser
Water ri
Rotary discharge table
.otary
preheater
Water-cooled jackets
.-T/Graphite electrodes
an conveyors to
recovery system
FIGURE 8-17-7
ELECTROLYTIC ZINC PROCESS(H)
NONFERROUS METALS INDUSTRY
8-17-12
-------
WAS TE PARAMETE RS(mg/1)
TABLE 8-17-1
NONFERROUS METALS
RAW WASTEWATER CHARACTERISTICS
SUBCATEGORY
Primary Secondary
Bauxite Aluminum Aluminum
Refining Smelting Smelting
ABC
Flow, GPD Red Mud
Discharge
17-20%
.QI-.I
1 ifta
TSS ~~ 10
00
I
|^
1
LJ
TDS
COD
Copper
Zinc
Fluoride
Aluminum
Oil and Grease
Lead
20
15
15
0
10
(Wet Air
Scrubbing
Only)
- 800
- 1M*
- 150
- 1.4M*
- 70
- 20
200 -
2M* -
120 -
0.2 -
1*-
0.2-0
6 -
6 -
500
10M*
540
1.3*
3.6*
.7
500
14
Primary Cooper
Smelting and
Refining
D, E
Secondary
Copper
F
Lead
G
145M - 7M
25
160
20
0.01
0
No
0
0
- 500
- 15M*
- 450
- 25*
- 2.6*
Data
- 10
- 50*
10 -
150 -
10 -
0.2 -
0.3 -
0 -
Nil
2 -
140
2M*
40
8*
18*
35
8
35 - 500
500 - 1M*
8 - 200
0.1 - 0.2
0.5*- 10*
No Data
No Data
No Data
0.3-0.5
Zinc
H
0 - 1MM
25 - 250
450 - 4.5M*
0.01-0.3
5*-250*
Nil
0-10
0.02 - 1.3*
Notes: M = 1,000
MM = 1,000,000
*See Appendix 5 for parameters which may be inhibitory
to biological systems
-------
TABLE 8-17-2
NONFERROUS METALS INDUSTRY
RAW WASTEWATER CHARACTERISTICS
BASED ON PRODUCTION
WASTE PARAMETER
SUBCATEGORY
Primary Secondary
Bauxite Aluminum Aluminum
Refining Smelting Smelting
ABC*
Flow, (L/KKG) Red Mud Wet Air
Flow Type Discharge Scrubbing
) 1/3-2 KKG/KKG Only*
; TSS (Kg/KKG)
TDS (Kg/KKG)
COD (Kg/KKG)
Copper (Kg/KKG)
Zinc (Kg/kkg)
Fluoride (Kg/KKG)
Aluminum (Kg/KKG)
Oil & Grease
(Kg/KKG)
Lead (Kg/KKG)
0.5-16 22-85
1-24 200-2M
0.6-12 12-100
0.02-0.2
0.1-0.6
0.3-15
0.03-1.3 0.6-51
0.04-0.5 0.4-0.6
Primary Copper,
Smelting and Secondary
Refining Copper
D, E F
Lead
G
Zinc
H
1.2M - 57M
0.2
0.2
0.2
0
0
No
0
0.003
- 1
- 7
- 0.5
- 0.04
- 0.1
Data
- 0.03
- 0.03
0.1 - 10
0.02 - 35
0.002 - 2
0 - 0.6
0 - 0.5
0 -0.03
Nil
0.05 -8
0.35-2
1-2
0-0.7
0
0.004-0.04
No Data
No Data
No Data
Nil
0.5-2.5
0.2-40
0.1-0.6
Nil
0.1-0.5
No Data
No Data
0.04-0.2
0-0.02
Notes: M = 1,000
MM = 1,000,000
* Units gram/kilogram of magnesium removed
for all values in this column.
-------
Primary Aluminum Smelting (B)
Control of wastewaters consists essentially of using dry scrubbers
or recycling the water used in wet scrubbers.
Secondary Aluminum smelting (C)
Direct metal cooling wastewater can be eliminated by the use of
air cooling, or by recirculating with the use of cooling towers.
There are processes available that eliminate the fume (the
Derham process and the Alcoa process) thus eliminating wet
scrubbers.
Primary Copper Smelting (D) and Primary Copper Refining (E)
The wastewater from slag handling can be recycled back to the
system, with the slag being used for landfill. Impoundment of
other wastewaters and recirculation of the water from the pond
is practiced at most mills, thus eliminating water discharges.
Secondary Copper (F)
Contact cooling water can be clarified, cooled, and then recircu-
lated, eliminating a waste stream. Alternatives to this include
the use of air for cooling, and the use of non-contact- cooling
water (cooling through the molds instead of putting the cooling
water directly on the metal). Slag handling water can be
impounded and then recirculated.
Primary Lead (G) and Primary Zinc (H)
Impoundment and recycle (previously described) apply to these
two subcategories.
Treatment Technology
Much of the wastewater produced by this industry can be greatly
reduced or totally eliminated by in-plant control measures.
However, those streams that are only partly eliminated or not
controllable with in-plant measures can be treated by the follow-
ing systems:
1) neutralization (pH control)
2) clarification, with oil and grease removal
3) cryolite or lime precipitation
4) adsorption on activated alumina or activated carbon
5) reverse osmosis
8-17-15
-------
PHOSPHATE
1. General Industry Description
The phosphate manufacturing industry includes the production
of elemental phosphorus, phosphorus derived chemicals, and
other non-fertilizer phosphate chemicals. Phosphorus derived
chemicals are phosphoric acid (dry process), phosphorus
pentoxide, phosphorus pentasulfide, phosphorus trichloride,
phosphorus oxychloride, sodium tripolyphosphate, and calcium
phosphates. The non-fertilizer phosphate segment of the
industry includes defluorinated phosphate rock, defluorinated
phosphoric acid, and sodium phosphate salts. Mined phosphate
rock and wet process phosphoric acid are the basic raw materials
for this industry.
Wastewater volumes resulting from the production of phosphorus
are several orders of magnitude greater than the wastewaters
generated in any of the other product categories. Elemental
phosphorus is an important wastewater contaminant common to
all segments of the phosphate manufacturing industry if the
phossy water (water containing colloidal phosphorus) is not
recycled to the phosphorus production facility.
The phosphate manufacturing industry is designated by Standard
Industrial Classification (SIC) 2819.
2. Industrial Categorization
The phosphate manufacturing industry is broadly subdivided
into two main categories: phosphorus derived chemicals, and
other non-fertilizer phosphate chemicals. For the purposes
of raw waste characterization and delineation of pretreatment
information, the industry is further subdivided into 6 sub-
categories, as follows:
Main Category Subcategory Designation
1. Phosphorus Derived Phosphorus Production (A)
Chemicals Phosphorus Consuming (B)
Phosphate (C)
2. Other Non-Fertilizer
Phosphate Chemicals Defluorinated Phosphate Rock (D)
Defluorinated Phosphoric Acid (E)
Sodium Phosphates (F)
8-18-1
-------
3. Process Description
General
An overall product manufacturing flow diagram for the industry
is depicted in Figure 8-18-1. Manufacture of phosphorus
derived chemicals is almost entirely based on the production
of elemental phosphorus from mined phosphate rock. Ferro-
phosphorus, widely used in the metallurgical industries, is
a direct by-product of the phosphorus production process. Over
87 percent of elemental phosphorus is used to manufacture high-
grade phosphoric acid by the furnace or dry process as opposed
to the wet process which converts phophate rock directly into
low-grade phosphoric acid. The remainder of the elemental
phosphorus is either marketed directly or converted into
chemicals such as phosphorus pentoxide, phosphorus pentasulfide,
phosphorus trichloride, and phosphorus oxychloride. The furnace-
grade phosphoric acid is marketed directly, largely to the
food industry and to the fertilizer industry. Phosphoric acid
is also used to manufacture sodium tripolyphosphate which is
used in detergents and for water treatment, and calcium phos-
phate which is used in foods and animal feeds.
Defluorinated phosphate rock is utilized as an animal feed
ingredient. Defluorinated phosphoric acid is mainly used
in the production of animal food stuffs and liquid fertilizers.
Sodium phosphates produced from wet process acid as the raw
material are used as intermediates in the' production of clean-
ing compounds.
Phosphorus Production (A) - Phosphorus is manufactured by the
reduction of mined phosphate rock by coke in an electric
furnace, with silica used as a flux. Slag,ferrophosphorus
(from iron in the phosphate rock), and carbon monoxide are
reaction by-products. The standard process, as shown in
Figure 8-18-2, consists of three basic parts: phosphate rock
preparation, smelting in electric furnace, and recovery of
phosphorus. Phosphate rock ores are first blended so that the
furnace feed is of uniform composition. The blended rock is
pretreated by heat drying, by agglomerating the particles, and
by heat treatment. Sizing or agglomeration is accomplished
by pelletizing, briquetting, or flaking, and pre-formed agglo-
merates are then calcined in a rotary kiln. The burden of
treated rock, coke and sand is charged to the furnace by incre-
mentally adding weighed quantities of each material to a common
belt conveyor. The furnace itself has a carbon crucible, carbon-
lined steel sidewalls, and a concrete roof. The furnace is
extensively water-cooled. Slag and ferrophosphorus are tapped
periodically. The hot furnace gases, consisting of 90%
8-18-2
-------
Phosphorus Trichloride (B)
DO
I
M
CO
I
U)
Mined Phosphate Rock
Batch Reactor I Oxychlor
Phosphorus Pentojd.de (B)
Phosphorus Pentasulfide (B)
Phosphoric Acid (Dry) (B)
Ferrophosphorus (A)
Defluorinated Phosphoric Acid (E)
Wet Process Acid
Neutralization Sodium Phosphates (F)
Defluorinated Phosphate Rock(D)
FIGURE 8-18-1
PHOSPHATE MANUFACTURING INDUSTRY
PRODUCT MANUFACTURING FLOW DIAGRAM
-------
BURN EXCESS
CO
00
ilk
FIGURE 8-18-2
STANDARD PHOSPHORUS PROCESS FLOW DIAGRAM
-------
CO and 10% phosphorus, pass through an electrostatic precipitator
to remove the dust before phosphorus condensation. Down-
stream of the precipitator, the phosphorus is condensed by
direct impingement of a hot water spray, sometimes augmented
by heat transfer through water-cooled condenser walls. Liquid
phosphorus drains into a water sump, where the water maintains
a seal from the atmosphere. Liquid phosphorus is stored
in steam-heated tanks under a water blanket and is transferred
into tank cars by pumping or by hot water displacement. The
tank cars have protective blankets of water and are equipped
with steam coils for remelting at the destination.
There are numerous sources of fumes from the furnace operation.
The feeding operation generates dust, and fumes are emitted
from electrode penetrations and from tapping. These fumes,
consisting of dust, phosphorus vapor (which is immediately
oxidized to phosphorus pentoxide), and carbon monoxide are
collected and scrubbed. Principal wastewater streams consist
of calciner scrubber liquor, phosphorus condenser and other
phossy water, and slag quenching water.
Phosphorus Consuming (B) - This subcategory embodies the follow-
ing five products: phosphoric acid (dry process), phosphorus
pentoxide, phosphorus pentasulfide, phosphorus trichloride,
and phosphorus oxychloride. In the standard dry process for
the production of phosphoric acid, liquid phosphorus is burned
in the air, the resulting gaseous phosphorus pentoxide is
absorbed and hydrated in a water spray, and the mist is
collected with an electrostatic precipitator. Regardless of
the process variation, phosphoric acid is made with consumption
of water and no aqueous wastes are generated by the process.
Solid anhydrous phosphorus pentoxide is manufactured by burning
liquid phosphorus in an excess of dried air in a combustion
chamber. The vapor is condensed in a "barn" which is a room-
like structure. Condensed phosphorus pentoxide is mechanically
scraped from the walls using moving chains, and is discharged
from the bottom of the barn with a screw conveyor. Phosphorus
pentasulfide is manufactured by direct union of phosphorus and
sulfur, both in liquid form. The highly exothermic reaction
is carried out as a batch operation. Since the reactants and
the product are highly flammable at the reaction temperature,
the reactor is continuously purged with nitrogen. A water
seal is used in the vent line.
Phosphorus trichloride is manufactured by charging liquid
phosphorus into a jacketed batch reactor. Chlorine is bubbled
through the charge, and phosphorus trichloride is refluxed until
all the phosphorus is consumed. Cooling water is used in the
8-18-5
-------
reactor jacket and care is taken to avoid an excess of
chlorine and the resulting formation of phosphorus pentachloride.
Phosphorus oxychloride is manufactured by the reaction of
phosphorus trichloride, chlorine, and solid phosphorus pent-
oxide in a batch operation. Liquid phosphorus trichloride is
charged to the reactor, solid phosphorus pentoxide is added,
and chlorine is bubbled through the mixture. Steam is supplied
to the reactor jacket, water to the reflux condenser is shut
off, and the product is distilled over and collected.
Because phosphorus is transported and stored under a water
blanket, phossy water is a raw waste material at phosphorus
consuming plants. Another source of phossy water occurs if
reactor contents containing phosphorus are dumped into a sewer
line as a result of operator error, emergency conditions, or
inadvertent leaks and spills.
Phosphate (C) - This subcategory embodies two product types:
sodium tripolyphosphate and calcium phosphates. Sodium tri-
polyphosphate is manufactured by the neutralization of phosphoric
acid in mix tanks by soda ash or by caustic soda and soda ash,
with the subsequent calcining of the dried mono- and di-sodium
phosphate crystals. The product is then slowly cooled or
tempered to produce the condensed form of the phosphates.
The non-fertilizer calcium phosphates are manufactured by the
neutralization of phosphoric acid with lime. Although the
reactions are chemically similar, the processes for different
calcium phosphates differ substantially in the amount and type
of lime and the amount of process water used. Relatively pure,
food grade monocalcium phosphate (MCP), dicalcium phosphate
(DCP), and tricalcium phosphate (TCP) are manufactured in a
stirred batch reactor from furnace grade acid and lime slurry,
as shown in the process flow diagram of Figure 8-18-3. DCP
is also manufactured for livestock feed supplement use, with
much lower specifications on product purity.
Sodium tripolyphosphate manufacture generates no process wastes.
Wastewaters from the manufacture of calcium phosphates are
generated from dewatering of the phosphate slurry and wet
scrubbing of the airborne solids during product drying operations.
Defluorinated Phosphate Rock (D) - Fluorapatite phosphate rock
is the primary raw material for the defluorination process. Other
raw materials used in much smaller amounts but critical to the
process are sodium containing reagents, wet process phosphoric
acid and silica. The charge is fed into either a rotary kiln or
a fluid bed reactor. Fluid bed reactor requires a modular and
pre-dried charge. Reaction temperatures are maintained in the
1205-1366 C range, while the retention time varies from 30 to 90
8-18-6
-------
LIME
WATER
X X
\
f
MCP
MIX
TANK
s
/
SLURRY
HOLD
TANK
V
HOT GAS
SPRAY
TOWER
\
/
SIZING
X
PRODUCT
MCP
LIME
SLURRY
TANK
\
/
\
PHOSPHORIC
ACID
TANK
\
(_
WATER VENT
X t
SCRUBBER
X
WASTE
WATER VENT
X t
SCRUBBER
\
/
/
DCP
MIX
TANK
\
/
SLURRY
HOLD
TANK
\
/
CENTRIFUGE
WASTE
\
HOT GAS
/ J,
KILN
MILL
\
/
CYCLONE
\
/
TCP
MIX
TANK
\
/
SLURRY
HOLD
TANK
STEAM
1 X
VENT
/ t
DRUM
DRYER
\
/
SIZING
X
PRODUCT
TCP
WASTE
PRODUCT
DCP
FIGURE 8-18-3
STANDARD PROCESS FOR
FOOD-GRADE CALCIUM PHOSPHATES
8-18-7
-------
minutes. From the kiln or fluid bed reactor, the defluorinated
product is quickly quenched with air or water, followed by
crushing and sizing for storage and shipment. A flow diagram for
the fluid bed process is shown in Figure 8-18-4. Wastewaters
are generated in scrubbing contaminants from gaseous effluent
streams. This water requirement is of appreciable magnitude and
process conditions normally permit use of recirculated contaminated
water for this service. Leaks and spills are collected as part
of process efficiency and housekeeping. The quantity is minor
and normally periodic.
Defluorinated Phosphoric Acid (E) - One method for defluorinating
wet process phosphoric acid is by vacuum evaporation. Concentra-
tion of 54% P2°R acid to a 68-72 % P2°5 stren9"th is performed
in vessels which use high pressure (550-550 psig) steam or
externally heated Dowtherm solution as the heat energy source
for evaporation of water from the acid. Fluorine removal from
the acid occurs concurrently with the water vapor loss. A process
flow diagram for vacuum type evaporation is shown in Figure 8-18-5.
A second method of phosphoric acid defluorination is by the
direct contact of hot combustion gases with the acid. A combus-
tion chamber fitted with fuel oil or gas burners is mounted on
top of an acid containment chamber. Pressurized hot gases are
bubbled through the acid. Evaporated and defluorinated product
acid is sent to an acid cooler, while the gaseous effluents
from the evaporation chamber flow to a series of gas cleaning
and absorption equipment.
A third method of defluorinating phosphoric acid is by aeration.
Diatomaceous silica or spray dried silica gel is mixed with
commercial 54% P20r phosphoric acid. Hydrogen fluoride in the
impure phosphoric acid is converted to fluosilicic acid which
in turn breaks down to SiF and is stripped from the heated
mixture by simple aeration.
The major wastewater source in the defluorination processes
is the wet scrubbing of contaminants from the gaseous effluent
streams. However, process conditions normally permit use of
recirculated contaminated water for this service.
Sodium Phosphates (F) - Removal of impurities from the wet
process acid is performed in a series of separate neutralization
steps in the manufacture of sodium phosphates. The first step
is the removal of fluosilicates with recycled sodium phosphate
liquor. The next step consists of adding sodium sulfide to
the solution to precipitate the minor quantities of arsenic
present. Concurrently, barium carbonate is.added to remove the
8-18-8
-------
DEFL.UORINATEP PHOSPHATE ROCK
FLUID BED PROCESS
Phosphate
Rock
00
I
00
o
Fluidizing Gas
Make Up Water
1_I
To
Atmosphere
K.
r
/
f
Cyclone
Scrubber
.
\
r
uoncama
Water
Contaminated
Water to
Retention
; Agglomerated and
3efluorinated
Phosphate
Product
FIGURE 8-18-4
-------
PEFLUORINATED PHOSPHORIC ACID - VACUUM PROCESS
(Super Phosphoric)
Water
Water
Water
Steam
~ 1 T
am _ L _
54% Phos-
phoric Acid
oo
I
M
00
I
No. 2
Evapo-
rator
Shipping
Pump
Product
Cooler
Alternate Heat
Medium
j l
I
Alternate Heat Medium
' .. i Combustion
Gases
I
Fuel
Process
Water
To Cooling Pond
FIGURE 8-18-5
-------
excess sulfate. The partially neutralized acid still contains
iron and aluminum phosphates, and some residual fluorine. A
second neutralization is carried out with soda ash to a pH
level of about 4.0. Special heating, agitation, and retention
techniques are next employed to adequately condition the slurry
so that filtration separation of the impurities can be
accomplished. The remaining solution is sufficiently pure for
the production of monosodium phosphate which can be further con-
verted into other compounds such as sodium metaphosphate, di-
sodium phosphate, and tri-sodium phosphate. A process flow
diagram is shown in Figure 8-18-6. Wastewater effluents from
these processes originate from leaks and spills, filtration
washes, and gas scrubber liquors.
4. Wastewater Characterization
Wastewater characteristics of process effluents from each of
the 6 subcategories of the phosphate manufacturing industry
are shown in Tables 8-18-1 and 8-18-2.
5. Control and Treatment Technology
In-Plant Control
Significant in-plant control of both waste quantity and quality
is possible for most subcategories of the phosphate manufactur-
ing industry. Important control measures include stringent
in-process abatement, good housekeeping practices, containment
provisions, and segregation practices. In the phosphorus
chemicals industry (A,B,C), plant effluent can be segregated
into non-contact cooling water, process water, and auxiliary
streams comprising ion exchange regenerants, cooling tower
blowdowns, boiler blowdowns, leaks and washings. Many plants
have accomplished the desired segregation of these streams,
often by a painstaking rerouting of the sewer lines. The
widespread use of once-through scrubber waste should be dis-
couraged. However, there are several plants notable in this
respect which recycle the scrubber water from a sump, thus
satisfying the scrubber water flow rate demands on the basis
of mass transfer considerations while retaining control of water
usage.
The containment of phossy water from phosphorus transfer and
storage operations is an important control measure in the
phosphorus consuming subcategory (B). While displaced phossy
water is normally shipped back to the phosphorus-producing
facility, the current practice in phosphorus storage tanks is
to maintain a water blanket over the phosphorus for safety
reasons. This practice is undesirable because the addition of
8-18-11
-------
Wet >roc««« PhoKphoric Acad
00
I
M
00
I
M
NJ
Water
*a*2-12349 1/kkg
2j*j-2doO gal/8. c.
h
CONCENTRATE 1
^
CRYSTALLIZERS
w
'
H3P04
STORAGE-SETTLE
^ Na
jj ___ WUTJ
TANK
V
^
ER UOUOR
I
CAKE Na2S1F6 ..
UKJEK (ByProduPt)
E>
TANK
^ ASjSj to Solid Haste Disposal
-A..,, r.. j>
TANK
^
»s ^
1 FILTtK ^L O
HIGH GRADE
NEUTRAL
PHOSPHATE
DRYER
MONO SODIUM T CAKE
PHOSPHATE
STORAGE
v
1
Water to
Waste
Na,co, A
TANK |
X
ft &
" FILTER "
\[;
CONCENTRATE
' T '
- LIQUOR 1 V 5 ' CRYSTALS ^ V
1 SALTING
y :VAPORATOR
DRYER
^ NaOH
T ' 1 ^
' TANK
^
FILTER ~
' ^ '
TRI SODIUM
PHOSPHATE
LIQUOR
i
EVAPORATOH
^
CRYSTAL-
LIZERS
^
' t !k
MUD .,.
^
SALTING
EVAPORATOR
^ ^
SALT
LOCK
Hasoi
Na2CO3 \TO WASTE
3 4/
[. CENTRI- M 1"'3rv4
fL1SE_-T,,, I 1 "^TWOP
ERYSTAL 1_J
DRYER
^
T
TRI SODIUM PHOSPHATE
CRYSTAL
CRYSTALLIZERS
i t
! * SALT
MONO SODIUM
PHOSPHATE
M
CENTRI- f Na2HP04
FUGE MOTHER
^7 Tty LIQUOR
FURNACE
1
4r 1
SODIUM ^7 1
ETA PHOSPHATE »
CALCIMER DISODIUM
^__^ DUOHYT)RAT
^ ANHYDROUS
TETRA SODIUM PYRO
PHOSPHATE
CRYST
DRYER
^
PHOSPHATE DISOD
E OR CR
AL
\ f
Total Cont-minated
Effluent
7640-10013 l/kkg
(1B30-2400 gal/«.t.)
IUM PHOSPHATE
YSTAL
FIGURE 8-18-6
SODIUM PHOSPHATE PROCESS
From Wet Process
Phosphoric Acid
-------
TABLE! 8-18-1
PHOSPHATE MAKlTFACTUItlNO INDUSTRY
CO
t-l
GO
1
to
PARAMETER PHOSPHORUS
(mg/l) PRODUCTION
A
Flow Type C
BODj
SS 100
TDS
COO
pH
Phosphorus 21
P04 59
S04 260
F 126
HC1
Kg SO,
H3 P03 + Hj PO,.
HF, I^SiFg, HgSiOj
Chloride
Calcium
Magnesium
Aluminum
Iron
Arsenic
Zinc
Total Acidity 128
Total Phosphorus
RAW WASTIS CHARACTERIZATION
PHOSPHORUS PHOSPHATE DEFLUORINATED
CONSUMING PHOSPHATE ROCK
BCD
B B B
3
24,000-54,000 16
1,900-7,000* 2,250*
48
1.65*
7000*
350
1,930
0-800
0-34
17-500
1900*
101
40
12
58
8*
0.38*
5.2*
600
DEFLUORINATED
PHOSPHORIC ACID
E
B
15
30
28,780*
306
1.29*
4,770
967
65
1700*
106
260
180*
0.83*
5-3*
5,590*
SODIUM PHOSPHATE
F
B
31
460
1640*
55
7.8
240
15
90
95
250
*See Appendix 5 for parameters which may be inhibitory to biological systems.
B - Batch Process
C - Continuous Process
-------
TABLE 8-13-2
PHOSPHATE MAHUFACTORIHG INDUSTRY
PARAMETER PHOSPHORUS
(kg/kkg)" PRODUCTION
A
Flov Range 1*25,000
(1/Wts)
Flov Type C
BOO;
S3 1*2.5
IDS
COD
PH
Phosphorus 9
PO^ 25
sou m
F 53.5
KC1
HgSOj
Ha **0^ "^ **a ^^U
HF, H2S1F6, HgS103
Chloride
Calcium
Magnesium
Aluminum
Iron
Arienic
Zinc
Total Acidity 51*. 5
Total Pho«phoru»
RAW WASTE CHARACTERIZATIOH -
PHODUCTIOH BASED DATA
PHOSPHORUS PHOSPHATE DEFLUORMATED
CONSUMING PHOSPHATE ROCK
38,000 10,920 1*5,890
B B B
22.5-50 0.73
l*.0-ll*.6 103
2.2
1.65
15
16
88
0-3
0-1.0
0.5-2.5
12
1*.6
1.8
0.6
2.7
0.37
0.02
0.21*
27.5
DEFLUORIHATED
PHOSPHORIC ACID
E
18,020-70,510
B
0.27-1.06
0.5U-2.U
519-2>031
5.5-21.5
1.29
86-336
17.W58.1
1.17-1*. 58
30.6-120
1.9-7.1*3
1*.7-18.39
3.2-12.52
0.02-0.08
0.09-0.35
101-395
SODIUM PHOSPHATE
F
7,61*0-10,020
B
0.2-0.3
3.5-1*. 6
12.5-16.1*0
0.1|-0.52
7.8
1.8-2.36
0.1-0.13
0.68-0.90
0.72-0.91*
1.91-2.51
8-18-14
-------
makeup water often results in the discharge of phossy water.
One way to ensure zero discharge of phossy water is to install
an auxiliary tank to collect phossy water overflows from the
storage tanks. A closed-loop system is then possible if the
phossy water from the auxiliary tank is reused as makeup for
the main phosphorus tank. Another special problem in the
phosphorus consuming subcategory (B) is the inadvertent spills
of elemental phosphorus into the plant sewer line. Provision
should be made for collecting, segregating, and bypassing
such spills. A recommended control measure is the installation
of a trap of sufficient volume just downstream of reaction vessels.
In the phosphates subcategory (C), an important area of concern
is the pickup by stormwater of dust originating from the
handling, storing, conveying, sizing, packaging and shipping
of finely-divided solid products. Airborne dusts can be min-
imized through air pollution abatement practices. Stormwater
pickup should be further controlled through strict dust cleanup
programs.
In the defluorinated phosphate rock (D) and defluorinated
phosphoric acid (E) subcategories, water used in scrubbing con-
taminants from the gaseous effluent stream constitutes a signi-
ficant part of the process water requirements. In both sub-
categories, process conditions do permit use of contaminated
water for this service. Some special precautions are essential
at a plant producing sodium phosphates (F). All meta, tetra, pyro
and polyphosphate wastewater in spills should be diverted to the
reuse pond. These phosphates do not precipitate satisfactorily
in the lime treatment process and interfere with the removal
of fluoride and suspended solids. Since .unlined ponds are the
most common treatment facility in the phosphate manufacturing
industry, prevention of pond failure is vitally important. Failures
of these ponds sometimes occur because they are unlined and be-
cause they may be improperly designed for containment in times
of heavy rainfall. Design criteria for ponds and dikes should
be based on the anticipated rainfall and drainage requirements.
Failure to put in toe drainage in dikes is a major problem.
Massive contamination from dike failure is the major concern
for industries utilizing ponds.
Treatment Technology
The various wastewater treatment practices for each of the six
subcategories of the phosphate manufacturing industry are
summarized in Table 8-18-3. The removal efficiencies shown
pertain to the raw waste loads of process effluents from each
of the subcategories.
8-18-15
-------
TABLE 8-18-3
PHOSPHATE MANUFACTURING INDUSTRY
HASTEWATER TREATMENT PRACTICES
REMOVAL EFFICIENCIES (PERCENT)
CD
CO
I
»-
en
POLLUTANT AMD METHOD
IDS
1. Lime Treatment and Sedimentation*
TSS
1. Lime Treatment and Sedimentation*
2. Flocculation, Clarification and
Dewatering
TOTAL PHOSPHATE
1. Lime Treatment and Sedimentation*
PHOSPHORUS
1. Lime Treatment and Sedimentation*
2. Flocculation, Clarification and
Dewatering
SULFATE
1. Lime Treatment and Sedimentation*
FLUORIDE
1. Lime Treatment and Sedimentation*
(Effluent Level)
Lime Treatment and Sedimentation*
(Neutralization)
PHOSPHORUS PHOSPHORUS DEFLUORINATED DEFLUORINATED SODIUM
PRODUCTION CONSUMING PHOSPHATE PHOSPHATE ROCK PHSOPHORIC ACID PHOSPHATE
A B C D E F
99
99
97
99
99
92
73-97 97
98
99
98
99
90
98
6-8
99
96
6-8
88
6-8
Preceded by recycle of phossy water and evaporation of
some process water in Subcategories A, B and C.
-------
STEAM ELECTRIC POWER
1. Industry Description
Steam electric power plants are the production facilities of
the electric power industry. The industry also provides for the
transmitting and distribution of electric energy.
Unlike other industries, the product, electricity, cannot be
stored, and therefore, the industry must be ready to produce at
any given time all the product that the consumer desires.
Four (4) basic fuels are used in steam electric power plants.
They are: coal, natural gas, oil and uranium. The fuel is used
to generate heat, which converts water to steam. The steam is
then used to turn a steam turbine (producing mechanical energy).
The turbine in turn conveys the mechanical energy to a generator
converting mechanical energy to electric energy. Wastewaters
generally contain heat, chemicals and metals.
This industry is designated by Standard Industrial Classifi-
cations (SIC) 4911 and 4931.
2. Industrial Categorization
The subcategorization of the power industry is generally based
upon the age and size of the plant:
Generating Unit (A)
Small Unit (B)
Old Unit (C)
Area Run-off (D)
Generating Unit (A) - All units not classified as Old (C)
or Small (B).
Small Unit (B) - All units generating less than 25 megawatts
except those classified as Old (C). In addition, any unit which
is part of an electric utilities system with a total net generat-
ing capacity of less than 150 megawatts.
Old Unit (C) - All units generating 500 megawatts or greater
which were first placed in service on or before January 1, 1970.
Also, all units generating less than 500 megawatts which were
first placed in service on or before January 1, 1974.
8-19-1
-------
Area Runoff (D) - Discharges resulting from material storage
runoff and construction runoff that are associated with genera-
tion (A,B,C).
3. Process Description
As noted above, the subcategories have generally been based upon
age and size of plants. However, the process of generating
electricity is the same for all subcategories, and therefore,
the wastes produced are similar. Discussions below will, there-
fore, be based on the unit processes in power plants rather than
subcategories.
There are five (5) major unit processes involved in the genera-
tion of electric power. They are:
(1) Storage and handling of fuel related materials, both
before and after use.
(2) Production of high-pressure steam.
(3) Expansion of the steam in a turbine, which drives the
generator.
(4) Condensation of the steam leaving the turbine.
(5) Generation of electric energy by the generator.
Refer to the flow diagrams in Figures 8-19-1 and 8-19-2.
Materials Storage and Handling - (1) All fuels must be deliv-
ered to the plant site, stored until used, and the spent fuel
materials stored on the premises.
Storm runoff from coal piles and oil spills from oil storage
can be sources of wastes. Contact of coal with air and moisture
results in oxidation of metal sulfides present in coal, to sul-
furic acid. Liquid drainage from coal storage piles presents
a potential danger of pollution. Sometimes these piles are
sprayed with tar to seal the outer surface. Ground seepage can
be minimized by storing the coal on an impervious vinyl liner.
Coal pile runoff is commonly characterized as low pH, and high in
dissolved solids. High concentrations of metals may also be
present.
8-19-2
-------
Steam
Fuel Inlet
CD
i
M
vo
10
Boiler
Ash Outlet
Turbine
Boiler Feed Water
Condenser
Boiler Feed
Pump
Electric
Generator j -
Power
.Cooling Water In
^.Cooling Water Out
Figure 8-19-1
Process Flow Diagram
Steam Electric Power Industry
-------
00
I
Water for
Feed Water Conb'n. Air
Once Through
_«_cooling Water
Sanitary Wastes, Laboratory &
Sampling Wastes, Intake Screen Back-
wash, Closed Cooling Water Systems
Construction Activity
LEGEHD
Misc. Waste
Hater Streams
. Liquid Flow
- Gas & Steam Flow
^,J,^,J,J,.,JJ,.. Chemicals
^Optional Flow
FIGUEE 8-19-2
TYPICAL FLOW DIAGRAM - STEAM ELECTRIC" POWER(FOSSIL-FUELED)
-------
The fuels are transported from the storage facilities to the furn-
ace where combustion takes place. Combustion generates non-combust-
ible residues called ash. The portion of ash carried along with
the hot gases is called fly ash, and the portion that settles to
the bottom of the furnace is called bottom ash. Coal produces a
relatively large amount of bottom ash. Oil produces little bot-
tom ash, but substantial amounts of fly ash. Natural gas prod-
uces little ash of any type.
Ash may be conveyed to the disposal site by either wet or dry means.
Most utilities have installed a sedimentation facility, to handle
coal ash, whereas oil ash may be recycled into the furnace or re-
moved by water washing. Since there is a large variation in fuel
quality, wastewater concentrations may vary considerably. Some
ash sluice waters contain significant concentrations of,metals.
The radioactive wastes generated in a nuclear power plant are
handled internally. The low level radioactive discharges are
carefully regulated.
Steam Production (2) - Peed water is introduced into the boiler
feed pump and first enters a series of tubes near the point where
the gases are exiting the boiler. The water is heated by the
existing gases, which in turn cools the gases. The water then
flows to one or more drums connected by a series of tubes. These
tubes are arranged vertically along the combustion zone of the boiler,
where the water is converted to steam. The water and steam are
separated in the boiler drum, and the steam leaving the drum is
heated further in the superheater section of the boiler. The
superheated steam then leaves the boiler and passes to the turb-
ine. The boiler drum is purged periodically to prevent build-up
of impurities in the boiler. This waste stream will contain
heavy metals and corrosion inhibitor chemicals used in the system.
Due to losses in the steam cycle, such as boiler blow-down,
water must be added to the system as replacement. Since the
steam cycle requires high quality water, the "make-up" water must
be demineralized (de-ionized). The regeneration of the demineral-
izers constitues a waste stream which will be high in dissolved
solids with either very low or very high pH values. In many cases,
the make-up water is "pretreated" before demineralization, by
clarification and filtration. This will provide clarifier slud-
ges and filter backwash streams.
8-19-5
-------
Periodically the boiler will be chemically cleaned to remove
scale and corrosion products from the boiler tubes. The waste-
water produced from this procedure will be high in heavy met-
als, spent acid and caustic solutions, oil and grease, and
extreme pH values.
In addition to chemically cleaning the boiler tubes, other
sections of the boiler will be cleaned, such as the air pre-
heater and the fire side of the tubes, which will produce waste
streams high in oil and grease, suspended solids, spent chemi-
cals, and extreme pH values.
Steam Expansion (3) - The steam expands in the turbine converting
the pressure energy to mechanical energy. By superheating the
steam to a proper point, the expansion will take place with only
small amounts of the steam condensing to water in the turbine.
In many power plants, there are two turbines in series, one high
pressure, and one low pressure. The steam exiting the high pres-
sure turbine is reheated in the boiler before entering the low
pressure turbine. No waste products are associated with this
process.
Steam Condensation (4) - The steam leaving the turbine is con-
densed in a heat exchanger, or condenser, creating a low turbine
exhaust pressure. The condensing actually causes a vacuum con-
dition, creating high energy conversion efficiencies in the tur-
bine. The condensed steam is then repumped to the boiler, com-
pleting the cycle.
The condenser is basically a shell and tube heat exchanger with
water being used as the coolant. The cooling system can either
be of the once-through or closed cycle type. In the once through
system, water is drawn from a large body of water such as a river
or lake, passed through the condenser and returned to the receiv-
ing body.
In the closed cooling system, the cooling water leaving the con-
denser is cooled in a cooling tower or cooling pond and then
recycled back to the condenser.
In the once-through system, high volumes of water are used, and
the only waste associated with it are heat, and free available
chlorine. (Chlorine is used to inhibit biological growth in the
condenser system).
8-19-6
-------
In the closed system the cooling tower will be periodically
purged to prevent build-up of dissolved solids, and this blow-
down stream will contain scaling inhibitors used in the cooling
tower, turbidity and dissolved solids.
Generation of Electricity (5) - The turbine is directly con-
nected to a generator, which converts mechanical energy to
electric energy at almost 100% of theoretical efficiency- There
are no wastes associated with this process.
4. Wastewater Characteristics
See Table 8-19-1 for wastewater characteristics of the industry.
5. Control and Treatment Technology
As indicated in Table 8-19-1, many wastewater streams are prod-
uced in batches which contain extreme pH ranges. Equalization
and batch treatment facilities can provide simple economical
removals of oil & grease and heavy metals, and also prevent large
wastewater fluctuations to the municipal system.
Alternate water treatment schemes can be instituted if metal-
containing water treatment chemicals cause treatment problems.
Wastewater flow rates can be reduced through increased recycl-
ing. Table 8-19-2 contains percentage removals- of pollutants
by various treatment methods.
8-19-7
-------
TABLE 8-19-1
RAW WASTEWATKR CHARACTERIZATION
STEAM ELECTRIC PCWER INDUSTRY
PARAMETER
OPERATION
mg/1 Water Treatment
Clarification
Wastes
Flow Range (gpd) 10 - 10M
Flow Type C
BOD 0-60
TSS 10 - Ito M
COD 0 - 1M
pH Neutral - High
Surfactants
Chromium 0-3*
co Copper 0-2*
«> Iron 0 - 1500*
00
Lead
Manganese
Mercury
Nickel 0-1
Selenium
Vanadium
Zinc 0-5*
Phosphorous 0-20
Phenols Present
Ammonia 0-1
Oil and Grease
M thousand
MM million
C continuous
B batch
Ion-Exchange Boiler Cooling Tower Coal Pile Cleaning Wastes Ash Pond
Wastes Blowdown Blowdown Drainage Boiler Tubes Air Preheater Boiler Fireside Overflow
1M - 80M 1M - 30M - 30M - 2MM 800 - 3M 8OM - toOM 50M-3MM 20M-1MM 3f« - 5MM
BCBBBB B C
1 - 100 0-5 0 - 100 No Data 0 - 100 O - 6 1-6 Ho Data
0-200 0-20 10-500 Ho Data 150 - 2500 20O - 2M 200-700 1-100
0-100 0 - to 1-500 Ho Data 1M - 3M 20-200 100-200 No Data
Low and High Neutral - High Neutral 2-8 Low & High Low & High Low & High Ho Data
Present Present
0-1 0-2 0-0.1 No Data 0.2-6* 6 - 12* 0-5* 0 - 0.1
0-3* 0 - 2.0 0-2* 1 - k* 50 - 200* 5 - 10* NIL NIL
0 - to* 0-2.0 0^1 0.1 - 5M* 50 - 500* 2 - 1,000* 50 - 150* 0-3
Present Present
0-1 0 - 0.1 NIL
Present Present Present Present
0-1 0-0. 10-1 80* 50 - 75* 5* NIL
Present Present Present
Present Present Present
0 - k. 5* 0-1* 0-3* 1 -15* 20 - 50* 5* 5-10* 0 - 0.1
0-90 0-50 2-20 NIL - 0.2 - k 1-2 0-2 0-0-5
NIL 0-0.5 0-0.1 Present Present
0-UOO 0-2 0-1 No Data 1-15 2-6 0-1 0-20
0-25 Present Present Present
.
Yard & Floor
Drains
1M - 5M
B
2 - k
0-5
No Data
Low - Neutral
Present
0 - 26*
No Data
No Data
Present
0 - 10*
No Data
Present
See Appendix 5 for parameters which may be inhibitory to biological systems
-------
TABLE 8-19-2
STEAM ELECTRIC POWER
WASTEWATER TREATMENT PRACTICES
Pollutant and Treatment Method % Removal
Oil & Grease
Gravity Separator 50-70%
Gravity Separator + Filtration 70-90%
Metals
Neutralization and Precipitation 50-95%
8-19-9
-------
FERROALLOYS
1. General Industry Description
This industry manufactures ferroalloys, a material which con-
stitutes a crude alloy of iron with some other metal, and is
used as an addition agent or alloying material in the produc-
tion of steel and other metals. Manganese is the most widely
used addition element in ferroalloys, followed by silicon and
chromium. Others include molybdenum, tungsten, titanium,
zirconium, vanadium, boron, and columbium. Principal products
include: silvery iron, ferrosilicon, silicon metal, ferro-
manganese, silicomanganese, ferromanganese silicon, charge
chrome, ferrochromium, ferrochrome silicon, manganese metal,
magnesium ferrosilicon, ferrotitanium, titanium alloys, vanadium
alloys, columbium alloys, calcium carbide, and chromium and
manganese metals.
The largest source of wfcterborne pollutants other than thermal
in this industry is the use of wet methods for air pollution
control. Production of ferroalloys has many dust and fume pro-
ducing steps. Consideration of air pollution control devices
is thus of crucial importance in determining the volume and
pollutant parameters of various wastewater streams.
The ferroalloy manufacturing industry includes Standard Industrial
Classifications(SIC) 3312, 3313.
2. Industrial Categorization
The ferroalloy manufacturing industry is broadly subdivided
into three main categories: the smelting and slag processing
segment, the calcium carbide segment, and the electrolytic ferro-
alloys segment. For the purposes of raw waste characterization
and delineation of pretreatment information, the industry is
further subdivided into seven subcategories as shown in Table 8-20-1,
3. -Process Description
The various ferroalloy manufacturing processes along with the
product groups manufactured by each process are listed in
Table 8^20-2, The production of ferromanganese in blast furnaces
is part of the steel making industry and is not considered herein.
Calcium carbide (D,E) is manufactured by the thermal reduction
of calcium oxide (lime) and coke in a submerged arc electric
furnace. Electrolytic processes are used for manganese (F)
and chromium (G). The other processes listed in Table 8-20-2 are
used for the prdduct groups in the smelting and slag processing
segment (A,B,C) of the industry.
8-20-1
-------
TABLE 8-20-1
FERROALLOY MANUFACTURING
Main Category Subcategory Designation
1. Smelting & Slag Open Electric Furnace with
Processing Wet Air Pollution Control
Devices (A)
Covered Electric Furnaces
and Other Smelting Operations
with Wet Air Pollution
Control Devices (B)
Slag Processing (C)
2. Calcium Covered Calcium Carbide
Carbide Furnaces with Wet Air
Pollution Control Devices (D)
Other Calcium Carbide
Furnaces (E)
3. Electrolytic Electrolytic Manganese
Ferroalloys Products (F)
Electrolytic Chromium (G)
8-20-2
-------
TABLE 8-20-2
FERROALLOY MANUFACTURING PROCESSES AND PRODUCT GROUPS
Manufacturing Process
Submerged-arc furnace process
Exothermic process
Electrolytic process
Vacuum furnace process
Induction furnace process
Product Group
Silvery iron
50, 65-75 percent ferrosilicon
Silicon metal
Silicon-manganese-zicronium
High-carbon(HC) ferromanganese
Silicomanganese
Ferromanganese silicon
Charge chrome
HC ferrochromium
Ferrochrome silicon
Calcium Carbide
Low-carbon(LC) ferrochromium
LC ferromanganese
Medium Carbon (MC) ferromanganese
Chromium metal
Titanium, vanadium, and columbium
alloys
Chromium metal
Manganese metal
LC ferrochromium
Magnesium ferrosilicon
Ferrotitanium
8-20-3
-------
Open and Covered Electric Furnaces and Other Smelting
Operations with Wet Air Pollution Control Devices (A, B)
The majority of electric ferroalloy furnaces are termed sub-
merged arc, although the mode of energy release is often
resistive heating. Raw ore, coke, and limestone or dolomite
mixed in proper proportions constitute the charge for the fur-
nace. The three electrodes are arranged in a delta formation
with the tips submerged into the charge within the furnace
crucible so that the reduction center lies in the middle of
the charge and reaction gases pass upward. The molten alloy
from the carbon reduction of the ore accumulates at the base of
the electrodes in the furnace and is periodically removed through
a tap hole. A smaller number of furnaces in the industry do
not operate with deep submergence of the electrodes and produce
a batch melt which is usually removed by tilting the furnace.
The conventional submerged arc furnace utilizes carbon reduction
of metallic oxides and continuously produces large quantities
of carbon monoxide (CO). Other sources of gas are moisture
in the charge materials, reducing agent volatile matter, thermal
decomposition products of raw ore, and intermediate reaction
products. The carbon monoxide content of the furnace off-gas
varies from 50-90 percent by volume, depending upon the alloy
being produced and furnace feed pretreatment.
Submerged-arc furnaces operate under steady-state conditions
and gas generation is continuous. In an open furnace, all the
CO burns with induced air at the top of the charge. In a covered
or closed furnace, most or all of the CO is withdrawn from the
furnace without combustion with air. Fume emissions also occur
at furnace tap holes. Because most furnaces are tapped inter-
mittently, tap hole fumes occur only about 10-20 percent of the
furnace operating time.
Ferroalloy production in submerged-arc furnaces consists of raw
materials preparation and handling, smelting, and product sizing
and handling as shown in Figure 8-20-1.
The exothermic processes using silicon or aluminum, or a combina-
tion of the two, are used less commonly than the submerged-arc
processes. In the exothermic process, silicon or aluminum
combines the oxygen of the charge, generating considerable heat
and creating temperatures of several thousand degrees in the
reaction vessel. The process is generally used to produce high
grade alloys with low carbon content. A process flow diagram
is shown in Figure 8-20-1 for the manufacture of low carbon ferro-
chromiunu
8-20-4
-------
FUMES
00
f
to
o
I
U1
CRUSHING
SCREENING
STORAGE
SHPMENT
FIGURE 8-20-1
FERROALLOY PRODUCTION FLOW DIAGRAM
-------
E
LECTRODES
Cr ORE
QUART -
ZITE
E
ECTRODES
COKE
WOOD
CHIPS
Cr ORE
FeCrSi
SUBMERGED-ARC
FURNACE
REACTION LADLE
REACTION LADLE
LIME
Cr ORE/LIME MELT
OPEN-ARC
FURNACE
THROW-AWAY
SLAG
SECONDARY
THROW AWAY
SLAG
PRODUCT
LC FeCr
FIGURE 8-20-2
FLOW SHEET LC FERROCHROMIUM
8-20-6
-------
Air pollution control devices used in the electric furnace
production of ferroalloys include baghouses, wet scrubbers,
and electrostatic precipitators. Wet scrubbers generate
slurries containing most of the particulates in the off-gases.
Baghouses generally produce no wastewater effluents, except in
one case where gases from exothermic processes are cooled by
water sprays, scrubbed in wet dynamic scrubbers, and then
cleaned in a baghouse where the bags are periodically washed
with water. Spray towers used to cool and condition the gases
before precipitators produce slurries containing some of the
particulates in the gases. Wet scrubbers are the only APC
device used on covered furnaces in this country. Electrostatic
precipitators are in use on only two open furnaces producing
ferrosilicon, ferrochromesilicon, high-carbon ferrochromium,
and silicomanganese. Other sources of wastewater result from
cooling uses, boiler feed, air conditioning and sanitary uses.
Slag Processing (C)
Some of the electric-arc smelting processes produce slag along
with the ferroalloy product. These are: low carbon ferro-
chromesilicon, high carbon ferrochromium, high carbon ferro-
manganese, and silicomanganese. The entrapped metal in the
slag is recovered by crushing and separation of the metal by the
wet sink-float process, called slag concentration. The slag
fines are also separated from the heavier particles so that the
secondary product is slag of a size suitable for road building
and similar purposes. This process is usually applied to
ferrochromium slags for recovery of chromium which is recharged
to the furnace. Another method consists of rapid quenching of
the molten slag in a large volume of flowing water. This pro-
duces a small-sized particle (shot) which can be readily leached
with acid to produce the electrolyte solution for electrolytic
ferroallpy manufacture. Suspended solids,chromium and manganese
are the important pollutants contained in slag processing wastewaters,
Calcium Carbide Furnaces (D, E)
Calcium carbide is manufactured by the thermal reduction of cal-
cium oxide (lime) and coke in a submerged-arc electric furnace. A
process flow diagram for the covered furnace calcium carbide man-
ufacture is shown in Figure 8-20-3. The only source of process
water pollutants is the use of wet air pollution control devices
such as scrubbers. Wastewaters typically include suspended
solids, cyanide, iron, silicon and calcium. Use of dry air pollu-
tion control devices result in zero discharge of process waste-
water.
8-20-7
-------
LIME
METALURGICAL
COKE
I
DRYER
SILO
I
SCREEN
i
PACKAGE
i
SHIP
DRY
COLLECTOR
SILO
FURNACE
1
AIR COOL
1
CRUSH
to< NON -CONTACT
*
SCRUBBER
SCRUBBER 1
WASTE
CO GAS
TO OTHER
PROCESSES
DRY
COLLECTOR
FIGURE 8-20-3
COVERED FURNACE CALCIUM CARBIDE PROCESS
FLOW DIAGRAM WITH WET AIR POLLUTION DEVICE
8-20-8
-------
Electrolytic Manganese Products (F)
Manganese is produced by the electrolysis of an electrolyte
extracted from manganese ore or manganese-bearing ferroalloy
slag. A process flow diagram for the manufacture of electro-
lytic manganese is shown in Figure 8-20-4.
The process is essentially a four-step operation, namely,
roasting the ore, leaching the ore, purifying the leach liquor,
and electrolysis. The ground and roasted ore is leached with
recycled anolyte from the electrolytic cell. Overall extraction
of manganese from the roasted ore is 98-99 percent. The neutral
leach liquor also contains iron, arsenic, copper, zinc, lead,
nickel, cobalt and molybdenum, which must be removed before
electrolysis. This is accomplished by treatment with hydrogen
sulfide gas or ammonium sulfide and filtration of the liquor
to remove the sulfide. The purified solution for electrolysis
enters the cathode compartment, where managese is plated on the
cathode. Manganese dioxide is prepared synthetically by electro-
lysis of manganese sulfate in a sulfuric acid solution. Waste-
water streams from electrolytic manganese production contain T55,
manganese, ammonia-nitrogen, and sulfate as the significant
pollutants.
Electrolytic Chromium (G)
High-carbon ferrochromium produced in the electric furnace is the
most readily available, cheapest, and one of the purest feedstocks
of. electrolytic chromium. A process flow diagram for the pro-
duction of electrolytic chromium is shown in Figure 8-20-5.
Ferrochromium is fed to a leach tank and dissolved in a mixture
of reduced, anolyte, chromium alum liquor and makeup sulfuric
acid. During the reaction, a large volume of hydrogen is released
and a ventilating system, necessary to maintain hydrogen concen-
tration below explosive limits, exhausts the gases to a scrubber.
The slurry is then fed to a holding tank where cold liquor, coming
from the ferrous amonium sulfate crystallization, is added to
cool the batch. Undissolved solids are separated from the solu-
tion and this residue is washed with water and discarded. Ammonium
sulfate is added to this solution and ferrous ammonium sulfate
crystals then separated on a vacuum filter, dried, and sold for
fertilizer. The filtrate is advanced to a conditioning tank,
where the chromium is converted to the non-alum-forming modifica-
tion by holding at elevated temperatures for several hours. The
conditioned liquor is clarified and sent to the aging circuit.
The crystal slurry is filtered and washed. The filtrate is
pumped to the leach circuit and the washed chromium-alum crystals
are dissolved in hot water to produce cell feed. The electro-
lytic cells are covered and are strongly ventilated to reduce the
ambient hydrogen and hexavalent chromium concentrations in the
cell room. Cathodes are withdrawn periodically from the cells
and the plated metal is stripped,crushed, and washed with hot water
to remove soluble salts. Wastewaters are characterized by signif-
icant concentrations of chromium, hexavalent chromium and calcium.
8-20-9
-------
ORE SHED
ANOLYTE
DRYER
1
STORAG
i
i
E BIN
GRINDERS
STORAGE TANK
REDUCING FURNACE
LEACHING TANK
CLARIFIER
REPULPING TANK
MOORE FILTER
OLIVER FILTER
FILTRATE
COOLING TOWER
SALTS]
ANOLYTE
ICATHQLYTE STORAGE
FILTER
[PURIFIED CATHOLYTE
ELECTROLYSIS CELLS
MANGANESE METAL
->l UNDERFLOW
SOLIDS
TO
WASTE
MUD TO WASTE]
FIGURE 8-20-4
ELECTROLYTIC MANGANESE FLOWSHEET
8-20-10
-------
00
1
10
o
HJGH CARBON
FERROCHBCME
(FINEL» GHOUND)-
UOillf. H2S04 CHHOMC AGO, AMMONUM SULFATEl
MOTHER LIQUOR
FBOM FERROUS
AMMONIUM
SULFAtE
SOLUTCN OF IRON
AUUONIUM AND
CHROMUU &ULFATES
SlICEOUS
RESOUE
CATHOLYTE SOLUTION
DnN.ENT OOOWIH, AMMDMUM SULFATE
W< ' ' 1
0 O
LEACHING COOt"*
TANK TANK
AMMONRM < OftQMRJU SU.f*Tl
I
T ' I
TANK
4o «
S MO'MER LOUOR l^
FILTRATE » FED
)S
>ME T
ATf S
T .-SODIUM
I I CARBONATE
"V "^
(RUBBER X^~N
fW|_^
.STEAM, r-*
WOITIOWNC I \ .X
- [y
CRU
SUL
CRY
SLU
M2°>^L_^
FITER
DE K>N
FATE
iTALS
A*i>
WASH MATER
mssotvfRJ
FILTER
WON
SULFATE
T ' 1 '
SETTLERS Y 1
FOR AGING ' » '
A CR.TSTALLI?ATON
p»VACUUU
-------
4. Wastewater Characterization
Wastewater characteristics of raw effluents from each of the
seven subcategories of the ferroalloy manufacturing industry
are shown in Table 8-20-3.
5. Control and Treatment Technology
In-Plant Control
Significant in-plant control of both waste quantity and quality
is possible for most subcategories of the ferroalloy manufactur-
ing industry. In the smelting and slag processing segment
(A, B, C), water is used for five principal purposes: Wet
scrubbing for air pollution control devices, cooling, sanitary,
slag processing, and drainage from slag or raw material storage.
The quantity and composition of emissions from ferroalloy
furnaces have a major impact on the potential for water pollution
in those plants using wet air pollution control devices. Higher
emission levels often occur after interruptions in furnace
operations due to electrode failure, metallurgical problems,
serious water leaks, furnace hearth failure, major taphole problems,
or electrical system failure. Close supervision and mainten-
ance are required to prevent frequent furnace shutdowns and
control emission levels. Similarly, the choice of air pollution
control devices is of importance in affecting wastewater volumes.
Open furnaces produce greater volumes of gas than do covered
furnaces. The use of dry baghouses on open furnaces can eliminate
all wastewater effluent from this source.
Water recirculation in both the scrubber system and the furnace
cooling water system is an important control measure in reducing
the wastewater volumes to be treated. Makeup for the scrubber
system can be obtained from blowdown from the cooling water
system. The scrubber effluent can be treated to oxidize the
cyanides and a flocculant aid added to improve sedimentation in
the thickener to which all of the scrubber water is discharged.
The thickener overflow can then be recycled to the scrubbers.
In the calcium carbide segment (D, E), cooling water, either
once-through or recycled, should be relatively free of wastes.
Any contaminants present would come from leaks or recycle build-
ups which are handled as ancillary water blowdown. In either
event, cooling waste contributions should be small and treatment
should not normally be needed. Other control measures include
containment of rainwater runoff from ore piles, and safeguards
against pond failures.
In the electrolytic ferroalloys segment (F, G), recirculation
and reuse of water is the most generally applicable and singly
most effettive method of reducing the discharge of pollutants.
So long as any required blowdown discharge is treated to the
8-20-12
-------
TABLE 8-20-3
FERROALLOY MANUFACTURING INDUSTRY
CO
1
o
1
I-1
OJ
Parameter(mg/l )
Flow Range(GPD)
Flow Type
TSS (mg/1)
TOS
Total Chromium
Hexavalent
Chromium
Manganese
Total Cyanide
Phenol
Iron
Silica
Calcium
Ammonia - N
Sulfate
PH
Open Electric
Furnace with Met
Air Pollution
Control Devices
A
C
1460
4.76*
0.32
613*
7.2
Covered Electric
Furnace & Other
Smelting Operations
with Wet Air
Pollution Control
Devices
B
C
1555
4.76*
0.32
447*
2.49*
7.27
6.0 - 9.0
Raw Uastewater Characteristics
Covered Calcium
Carbide Furnaces
with Wet Air
Slag Pollution Control Other Calcium
Processing Devices Carbide Furnaces
C D E
112M - 148M 659M - 1648M
C C C
864 3750
302
2.04*
54*
27*
14.2*
2.9
397
6.2
Electrolytic
Manganese Electrolytic
Products Chromium
F G
150M 21 OH
C C
2 - 900 290
1764*
27*- 124* 52*
4492*
87 - 94 1076*
180 - 688
2.7* - 7.3 2.9*
Note: *Se« Appendix 5 for parameters which may be Inhibitory to biological systems.
M -Thousand C - Continuous
-------
same effluent concentration as once-through water, the load
reduction for each contaminant will be in direct proportion
to the percentage of water recirculated. Water quality
restrictions can generally be handled by using fresh makeup
water at the points requiring high quality water.
Treatment Technology
The various wastewater treatment practices for each of the
subcategories are summarized in Table 8-20-4.
8-20-14
-------
03
I
10
O
I
M
U1
TABLE 8-20-4
FERROALLOY MANUFACTURING INDUSTRY
WASTEWATER TREATMENT PRACTICES
REMOVAL EFFICIENCIES (PERCENT)
Pollutant & Method
Suspended Solids
1. Water Recirculation, lagoons,
clarifler-Flocculators
2. Lagoons, clarifler-flocculators,
sand filters and process water
recirculation
Chromi urn
T Hexavalent chromium reduction,
precipitation, sedimentation
Cyanide
K Alkaline chlorination
Manganese
Open Electric
Furnace with Wet
Air Pollution
Control Devices
A
98
99
89
Covered Electric
& Other Smelting
Operations with Wet
Air Pollution
Control Devices
B
98
99
89
80
Slag
Processing
C
97
98
76
Covered Calcium Other
Carbide Furnaces Calcium
with Wet Air Poll- Carbide
ution Control Devices Furnaces
D E
98
99
80
Electrolytic
Manganese
Products
F
97
99
90
Electrolytic
Chromium
G
97
99
90
Y. Neutralization of add salts,
precipitation, and sedimen-
tation
Phenol
1. Breakpoint Chlorination,
activated carbon
Iron
1. Neutralization, precipitation,
and sedimentation
Calcium
1. Water circulation, lagoons,
cl ari f ier-f loccul ators
98
98
94
81
81
92
98
98
80
98
Neutralization
97
97
97
97
97
97
-------
LEATHER
1. General Industry Description
Tanning is the process of converting animal hides into leather.
The hides are unhaired, tanned by reacting with one or a
combination of tanning agents, dyed and finished to produce
a finished leather. Seventy-five percent of the industry's
wastewaters are discharged to municipal sewer systems.
Establishments engaged in this industry are covered by Standard
Industrial Classification(SIC)3111.
2. Industrial Categorization
A useful categorization for the purposes of raw waste character-
ization is given in Table 8-21-1.
3. Process Description
The subcategories in Table 8-21-1 include various combinations
of four basic operations:
a. Beamhouse
b. Tanhouse
c. Retan, color, and fatliquor
d. Finishing
Discussion begins with a description of these four basic operations
and follows with a definition of the subcategories based on these
operations. Figure 8-21-1 shows a flow diagram for a typical
cattlehide tannery.
Beamhouse
In the beamhouse,hides are processed in order to prepare them for
the tanning operation. Hides that have been cured with salt or
brine are received, stored, trimmed, and soaked to restore moisture
and to remove salt. Wash waters contain dirt, salt, blood, manure
and proteins, which are high in BOD, COD, dissolved and suspended
solids.
Degreasing operations with either hot water and detergent or
solvent are performed on pig and sheep skins. Much of the grease
and solvent are recovered, but quantities of grease, BOD, COD and
suspended solids enter the waste stream.
Fleshing, the removal of fatty tissue and meat from the hides,
is accomplished on a fleshing machine, through the use of rotating
blades. Cold water, necessary to keep the fat congealed, generates
a fatty wastewater. Fleshings are recovered and sold to plants
for rendering or for conversion to glue.
8-21-1
-------
TABLE 8-21-1
LEATHER TANNING AND FINISHING
Subcategory Designation
Hair Pulp Unhairing with Chrome
Tanning and Finishing A
Hair Save Unhairing with Chrome
Tanning and Finishing B
Hair Save Unhairing with Vegetable or Alum
Tanning and Finishing C
Finishing of Tanned Hides D
Vegetable or Chrome Tanning of
Unhaired Hides E
Unhairing with Chrome Tanning
and No Finishing F
8-21-2
-------
FLOW DIAGRAM
TYPICAL CATTLEHIDE TANNERY
HIM
mKi in uit«u ~-~
ntuu niiiiu
Lltllll Ullll
K'KUSt
KIW.CDirjB.fllLIOlOl
4
JIIUL_
Kllll IMIUHI (Clt*jl-UP_OlilTl
FIGURE 8-21-1
Leather Tanning and Finishing
8-21-3
-------
Beamhouse operations are classified according to one of two
hair removal practices. Machine removal permits hair recovery
and is practiced in a "save hair" beamhouse. The dissolving
process is referred to as "pulping" and is practiced in a
"pulp hair" beamhouse.
Prior to unhairing, the hides are slurried with lime and other
additives, primarily sulfide sharpeners, to loosen the hair
before its removal. Following unhairing the hides are sometimes
relimed to make the hide swell for easier splitting and to
assure complete hair follick removal.
The liming and unhairing processes are among the principal
contributors to the waste effluent. In a save hair operation
with good recovery of hair, the contribution to the effluent
is substantially lower than in the pulp hair operation. The
waste is characterized by a high alkalinity, pH,sulfide,
nitrogen, BOD, COD, suspended and total solids content.
Tanhouse
The purpose of the tanning process is to produce a durable
material from the animal skin or hide which is not subject to
degradation by physical or biological mechanisms.
Bating is the first step in preparing the hide for the tanning
process. The hides are placed in vats or drums which contain
a solution of ammonium salts and enzymes, which delime the
skins, reduce the swelling, peptize the fibers and remove pro-
tein degradation products.
Bating is followed by pickling in a brine and acid solution
in order to condition the hide for receiving the tanning agent.
Principal waste constituents are acid and salt.
Tanning is accomplished by reacting the hides with a tanning
agent, usually chrome or vegetable tannins, although alum,
metal salts and formaldehyde can be used. Waste effluents
from the tanning process are substantial. Recycle and recovery
of tanning agents are becoming more common. The spent chromium
tanning solution is relatively low in BOD, COD, and suspended
solids. On the other hand, vegetable tannin in the waste
is a large source of both BOD and color.
Retan, Color, Fatliquor
These three operations are usually performed in one drum.
Tanning solution is added to provide additional penetration
into the hides(retan); synthetic or vegetable dyes are added
to color the hides (color); oils are added to replace the
natural oils of the skin that were lost in the tanning process
(fatliquor). High strength, low volume discharges containing
oil and color are generated.
8-21-4
-------
Finishing
There are a number of finishing operations including drying,
coating, staking and sanding which are principally dry processes.
Pasting and washup operations generate a high strength low
volume wastewater.
Table 8-21-2 shows the varying combinations of processes which
determine the basis for subcategorization. Subcategory E
includes the chrome tanning of unhaired and pickled sheep
skins after removing the wool. There is generally no beam-
house process used for sheep or pig skins.
4. Wastewater Characteristics
Tables 8-21-3 and 8-21-4 contain raw wastewater characteristics
for the industry. Most processes are batch operated, generating
large fluctuations in wastewater strength and flow.
Sewerage systems are susceptible to damage from tannery wastes.
An alkaline sulfur bearing waste when mixed with domestic or
acidic waste will release hydrogen sulfide gas. Aerobic
bacteria oxidize hydrogen sulfide to sulfuric acid which is
corrosive to concrete and metal. Grease can coat sewer lines
and act as an adhesive for particulate matter.
Aerobic biological treatment systems would possible be seriously
inhibited by some tannery waste constituents. While normal
average concentrations of lime and chromium salts may not
damage the system, short term high concentrations could
possibly be detrimental to biological activity. Experience
with separate biological treatment of tannery wastewater has
not indicated a serious problem with inhibition and treatment
system upsets.
5. Control and Treatment Technology
Wide fluctuations in flow and strength can cause difficulties
for the municipal treatment plant. Reductions in BOD, sulfides
and chromium concentrations, as well as equalization of flow
may be required to avert overloading biological units. Methods
of reducing waste loads include:
a. Water conservation
b. Process solution reuse or recovery
c. Treatment to reduce a waste constituent
In-Plant Control
Water conservation measures in one tannery reduced water volumes
by nearly 50%. These measures include reuse of process waters
in the liming operations, screening and recirculating wash water,
recycling vegetable tannin and evaporating the water and substitut-
ing hide processors (concrete mixers).
8-21-5
-------
TABLE 8-21-2
LEATHER TANNING AND FINISHING
Principal Processes of Subcategories
Subcategory Beamhouse Tanning Finishing
A Hair Pulp Chrome Yes
B Hair Save Chrome Yes
C Hair Pulp or Save Vegetable or Alum Yes
D None None Yes
E None Vegetable or Chrome Yes
F Hair Pulp or Save Chrome No
8-21-6
-------
TABLE 8-21-3
LEATHER TANNING INDUSTRY
Raw Wastewater Characteristics
00
i
to
Parameter .(mg/1)
BOD
TSS
PH
Oil & Grease
COD
Total Nitrogen
Sulfide
Chromium
Alkalinity
Pulp-Chrome
Finish
A
2000*
2500
350*
5000*
350
150*
80*
2000
Save-Chrome
Finish
B
1100*
2300
700*
2200*
200
15
80*
1150
Unhairing-
Veg. -Finish
C
1400*
2700
650*
5000*
200
25
4*
1300
Finish
D
2000*
2400
400*
1500*
200
100*
130*
2000
Veg . or
Chrome
E
1100*
1400
400*
2700*
100
72*
20*
1100
Unhairing
Chrome Tanning
F
4000*
4000
9-11*
250*
8000*
600
150*
160*
1500
Note:
*See Appendix 5 for parameters which may be inhibitory to biological systems
-------
TABLE 8-21-4
LEATHER TANNING INDUSTRY
Raw Wastewater Characteristics - Production Based Data
00
1
NJ
1 '
1
00
Parameter (kg/kkg)
Flow Range (1/kkg)
Flow Type
BOD
TSS
Oil & Grease
COD
Total Nitrogen
Sulfide
Chromium
Alkalinity
Pulp-Chrome
Finish
A
7M/156M
B
5/270
7/600
.1/70
10/600
3/44
.1/46
.1/19
.5/300
Save-Chrome
Finish
B
1M/189M
B
20/140
30/350
.7/110
90/220
3.5/25
.1/3
.3/12
60/90
Unhairing
Veg-Finish
C
7M/106M
B
8/130
20/450
.1/160
25/700
1/25
.1/4
.2/.6
4/140
Finish
D
3M/33M
B
7/70
7/130
2.2/19
5.5/65
1/7
2
.4/5
40
Veg or
Chrome
E
6M/205M
B
10/140
3/870
.6/46
11/270
.6/30
4/5
.1/2.1
6.5/180
Unhairing
Chrome Tan
F
14M/56M
B
30/160
40/190
1/19
50/160
14/18
2/6.5
3.8/6
35/55
Note: M - thousand
B - batch process
kg/kkg - kilogram pollutant/1000 kilograms of product
produced (lower limit/upper limit)
1/kkg - liters of wastewater/1000 kilograms of product
-------
Reuse and recovery of tanning solutions, unhairing solutions,
pickle liquor, retan liquor, and pasting: frame water, have
been successfully accomplished, with significant reductions
in waste load.
Treatment Technology
Sulfides in the beamhouse waste constitute a potential problem
in subsequent handling. Sulfides are satisfactorily removed
by means of oxidation by air, chemical or catalytic methods.
Chromium is used exclusively in the trivalent form, which can
be precipitated and clarified with proper pH adjustment and
suitable equipment. However, some tanneries buy hexavalent
chrome and convert this to the trivalent from. Spills from the
storage of hexavalent chrome must be kept separate from other
wastes since it must be reduced to the trivalent state before
it can be removed by precipitation.
Other preliminary treatment operations consist of one or a
combination of the following: screening, equalization,
sedimentation, coagulation and sedimentation and secondary treat-
ment. With adequate pretreatment,tannery wastes are accept-
able to municipal treatment systems.
Table 8-21-5 contains removal efficiencies for some treatment
processes.
8-21-9
-------
TABLE 8-21-5
Leather and Tanning Industry Treatment Practices
Removal Efficiencies
Pollutant and Method Percent Removal
BOD
1. Sedimentation 30-60
2. Coagulation and Sedimentation 70-85
3. Biological treatment 70-98
TSS
1. Sedimentation 40-70
2. Coagulation and Sedimentation 80-95
3. Biological treatment 70-98
Grease
1. Sedimentation 50-90
2. Coagulation and Sedimentation 50-90
Chromium
1. Sedimentation 50-90
2. Coagulation and Sedimentation 90-98
8-21-10
-------
GLASS
1. General Industry Description
The Insulation Fiberglass segment of the glass manufacturing
industry is that part of the industry in which molten glass is
made into continuously fiberized and chemically bonded, wool-
like material. Several air pollution abatement methods
practiced by this industry produce large volumes of wastewater.
These discharges contain moderate amounts of phenol, dissolved
.solids, COD, and considerable amounts of suspended solids.
The flat glass industry involves the manufacturing of primary
flat glass by melting sand with other inorganic raw materials
at high temperatures, forming the molten mass into the basic
sheet by various methods and fabricating it into flat glass
products. Waters from cooling, washing and polishing operations
are the principal sources of waste discharges containing heat,
suspended solids, oils and occasionally phosphates. Water recycl-
ing is practiced throughout the industry to reduce the large
volume of dilute waste. Establishments engaged in this industry
are covered by Standard Industrial Classification (SIC) 3211,
3231, 3296.
2. Industrial Categorization
The industry has been categorized along process lines and sub-
categorized according to similarities in wastes as follows:
Category
Insulation Fiberglass
Flat Glass
Automotive Glass
Subcategory
Insulation Fiberglass
Sheet Glass
Rolled Glass
Plate Glass
Float Glass
Tempered
Laminated
Designation
A
B
C
D
E
F
G
8-22-1
-------
3. Process Description
Insulation Fiberglass (A)
Glass fiber has the ability to form low thermal conductivity
webs which retard, inexpensively, the transfer of heat. The
manufacture of the insulation itself is a simple, large-scale
process which has three distinct steps:
a. Glass melting
b. Glass spinning or fiberizing
c. Insulation binding and forming
Glass melting is performed in either a semi-batch Multiple
Remelt Furnace or in the more preferred Direct Melt Furnace
which melts the ingredients and feeds molten glass to the
fiberizers in one continuous operation.
Spinning or fiberizing molten glass is performed by either a
Flame Attenuation or a Rotary Spinning process. In the former,
molten glass from the furnace falls through fine holes bored
in platinum bushings and comes out as relatively thick fibers
which are drawn or attenuated into thin fibers by passing them
through a stream of high velocity hot gas. In the more
productive rotary process a single stream of molten glass is
fed into a spinning platinum basket containing a large number of
small holes in its wall and the molten glass is forced through
the holes by centrifugal force, thereby forming the fibers.
These fibers, too, are drawn or attenuated by high velocity,
hot gases and fall as a mass onto a moving conveyor.
The fibers are sprayed with a phenolic water soluble binder or
glue. This binder, a complex mixture of thermosetting organic
resins, oils, dyes, and chemical additives is a major source of
pollution from the plant. The glass fiber mat is conveyed through
the appropriate curing and cooling ovens on a conveyor to the
packaging department. During spraying the conveyors are exposed
to and collect deposits of the resinous binder which are removed
by hot caustic baths or by pressurized water sprays. The latter
is preferred because the sprayed water is amenable to treatment
and recirculation while spent caustic must be dumped.
8-22-2
-------
Insulation fiberglass plants experience both air particulate
and odor problems. Particulate emissions are found in the
exhaust gases of the glass furnace, forming area, and curing
and cooling ovens. The principal source of odors is volatilized
phenols. Several methods, involving both wet and dry processes,
are being developed in an effort to reduce the air emissions.
FIAT GLASS
Primary flat glass operations of batching, melting, forming and
cutting are basic to all glass manufacturing. In batching,
silica sand, soda ash, limestone, dolomite and cullet (broken waste
glass) are mixed. The mix is fed to a high temperature melt
tank that produces molten glass. Non-contact cooling waters
generate thermal discharge. The method by which the glass is
removed from the melt tank is the distinguishing factor among
subcategories B-G.
Sheet Glass (B)
In Sheet Glass (B) molten glass is drawn vertically from the
melt tank as a ribbon. The thickness of this ribbon of glass
is inversely proportional to the drawing speed. Wastewater is
produced in the fabricating operations on the produced sheet. No
water is used in the forming of sheet glass or in the first cutting.
If the glass is to be further fabricated, water may be used.
Rolled Glass (C)
Rolled glass is flat plate manufactured with decorative and diffuse
textures and can include safety wire inclusions. Rolled glass
is produced ,by gravity feeding molten glass through texturized
rolls which impart the desired surface, or by inserting wire
mesh between two ribbons of hot and soft glass which bond
together when they touch. Wastewaters are limited to thermal
discharges from cooling waters.
Plate Glass (D)
Plate glass manufacturing is the production.of high quality
thick glass sheet. Rough glass is produced by gravity feeding
molten glass between water cooled forming rolls. Rough glass
sheet is transformed to a quality glass finished product by
grinding and polishing with slurries of progressively finer
abrasives. The polishing residues are removed by a series of
washes and rinses. Large quantities of wastewater containing
suspended solids as well as large quantities of cooling water
are generated.
8-22-3
-------
Float Glass (E)
The manufacturing of flat glass by the float process is more
efficient and results in the discharge of much less wastewater
than the Plate Glass (D) process. In the float process, molten
glass is poured onto a molten tin suiface where heat and the
force of gravity combine to form a high quality plate glass
that requires no grinding and polishing. The underside of the
glass is sprayed with sulfur dioxide after forming to provide
a protective coating of sodium sulfate. This coating is sub-
sequently washed off before further fabricating. The elimination
of the grinding and polishing process, characteristic of plate
glass manufacturing, is the float process1 main advantage, and
results in significantly reduced wastewater volumes. Recycling
is practiced in the washing procedure with occasional blowdowns
to regulate dissolved solids build up. However, glass for
mirror manufacture has a higher quality rinse water requirement
precluding the use of recycled water.
FABRICATED AUTOMOTIVE GLASS
Tempered Glass (F)
Solid tempered automotive fabrication is the fabrication from
glass blanks of automobile back and side windows by a series
of operations in which flat glass is cut, drilled/ ground
smooth, bent and tempered in preparation for installation. The
grinding and washing operations produce water borne pollutants.
An oil-water emulsion used in the grinding process (as a coolant
and to remove glass particles) is the main source of oil and
suspended solids. Washing to cleanse the glass of residual
coolant and particles prior to tempering is another source of
wastewater. Both wastewaters are generally recycled. Cooling
water is required for tempering and quenching but the heat
rejected here is relatively low.
Laminated Glass (G)
Windshield .fabrication is the manufacturing of laminated wind-
shields from glass blanks and vinyl plastic. Two layers of
glass which have been cut and bent to proper size and curvature
are bonded with an inner layer of vinyl plastic. Bending to
appropriate curvature is accomplished in a heating lehr where
mating panels are shaped as a pair. The cementing is done in
8-22-4
-------
oil (usually) or air (more recently) autoclaves in which
adherence between the three layers is induced by high pressure
and temperature. Wastes are produced by the seaming (rough
grinding of sharp edges) and frequent washings that are necessary
to assure cleanliness of all glass and plastic surfaces before
bending and laminating. Slowdown from concentrated recycled
streams contains oils, suspended and dissolved solids, and some
detergent. Cooling waters generate thermal discharges.
4. Wastewater characterization
Sources of wastewater include cooling operations, equipment
cleaning, air pollution scrubbers, grinding and washing operations,
boiler blowdown and water treatment sludges. Table 8-22-1 contains
wastewater characteristics for the industry.
5. Control and Treatment Technology
In-Plant Control
The industry practices extensive recycling and reuse techniques
in order to reduce wastewater volumes. The following modifi-
cations can reduce water use:
Replace caustic baths with pressurized water sprays to
clean conveyors of fiber and resin.
Use water sprays with higher pressure to minimize water
consumption.
Reuse of chain wash water after suitable treatment.
Dispose of high dissolved solids blowdown in overspray
and binder dilution water.
Incorporate hood wash and miscellaneous process waters
in the chain wash system.
Recirculate cullet cooling water with blowdown to the
chain wash recirculation system.
In the windshield laminating process oil contamination can be
reduced to a trace by converting the process to air autoclaves
from existing oil units.
8-22-5
-------
TABLE 8-22-1
GLASS MANUFACTURING
RAW WASTEWATER CHARACTERISTICS
GO
to
M
1
-------
Treatment Technology
The large volumes of solids-laden wastewater are normally
treated by lagooning with polyelectrolyte added to increase
settling. The lagoon effluent can be recycled back to the
grinding and polishing steps. The quality of this effluent can
be improved by using two-stage lagoons and/or sand filters. Oils
can be removed by filtering through diatomaceous earth filters.
Table 8-22-2 co'ntains typical removals that can be expected from
various wastewater treatment practices.
8-22-7
-------
TABLE 8-22-2
WASTEWATER TREATMENT PRACTICES
GLASS MANUFACTURING
Subcategories (% Removal)
Solid
Fiber Plate Float Tempered Windshield
Pollutant and Method Glass Glass Glass Automotive Fabrication
Suspended Solids^
Settling Lagoon-plus
polyelectrolyte - 99.6 - -
Coagulation and
Sedimentation - 99.8 75
Sand Filtration - 99.9 -
Diatomaceous Earth
Filtration - - 66 95 80
Biological Treatment 97 - -
Phenol
Bioconversion 99.6 -
Oil
Settling Lagoon 90
Diatomaceous Earth
Filtration - 66 62 99.7
API Separation - - 98*
Air Flotation - 98
BOD
Diatomaceous Earth
Filtration - 33
Biological Treatment 98.5 -
COD
Settling Lagoon - 90 - - -
Diatomaceous Earth
Filtration - 33
API Separation - - 98*
Biological Treatment 95
* Assumes process has replaced detergent wash with hot water rinse
8-22-8
-------
ASBESTOS
1. General Industry Description
Asbestos is a group name that refers to several serpentine
minerals having different chemical compositions,but similar
characteristics. The most widely used variety is chrysotile.
As a natural mineral fiber, asbestos is strong, flexible, and
highly resistent to breakdown under adverse conditions. One
or more of these properties are exploited in numerous manu-
factured products by combining asbestos with other materials
such as binders, fillers, and additives for extensive appli-
cations. Principal product categories are asbestos-cement,
floor tile, paper and felts, friction products, textiles,
sprayed insulation, and packing and gaskets.
The increased concern over exposure to asbestos fibers in the
air is primarily responsible for the gradual conversion of
dry processes into wet processes in the industry. This trend
is expected to continue in the future.
The asbestos manufacturing industrial category has the follow-
ing Standard Industrial Classification (SIC) numbers: 3292,
3293,and 2661.
2. Industrial Categorization
The asbestos manufacturing industry is broadly subdivided
into two main categories: the building, construction, and
paper segment, and the textile, friction materials and seal-
ing devices segment. For the purposes of raw waste characteri-
zation and delineation of pretreatment information, the indus-
try is further subdivided into 11 subcategories, as shown below.
Process effluents from the building, construction, and paper
segment of the industry constitute the predominant source of
Wastewaters in this industrial category.
Main Category
1.
Building, Con-
struction, and
Paper
2.
Textiles, Fric-
tion Materials,
and Sealing
Devices
Subcategory
Asbestos-Cement Pipe
Asbestos-Cement Sheet
Asbestos Paper (Starch Binder)
Asbestos Paper (Elastomeric
Binder)
Asbestos Millboard
Asbestos Roofing Products
Asbestos Floor Tile
Coating, or Finishing, of
Asbestos Textiles
Solvent Recovery
Vapor Absorption
Wet Dust Collection
Designation
(A)
(B)
(C)
(D)
(E)
(F)
(G)
(H)
(I)
(J)
(K)
8-23-1
-------
3. Process Description
General
With the exception of roofing and floor tile manufacture, there
is a basic similarity in the methods of producing the various
asbestos products. The asbestos fibers and other raw materials
are first slurried with water and then formed into single or
multi-layered sheets as most of the water is removed. The
manufacturing process always incorporates the use of save-alls
(settling tanks of various shapes) through which the process
waste waters are usually routed. Water and solids are recovered
and reused from the save-all, and excess overflow and underflow
constitute the process waste streams. In all of these product
categories, water serves both as an ingredient and a means of
conveying the raw materials to and through the forming steps.
Asbestos-Cement Products (A, B)
The largest single use category of asbestos fiber is the manu-
facture of asbestos-cement products. The pipe segment is the
largest component in this product category. Asbestos-cement
products contain from 10 to 70 percent asbestos by weight,
usually of the chrysotile variety. Portland cement content
varies from 25 to 70 percent. The remaining raw material, from
5 to 35 percent, is finely ground silica.
Asbestos-cement products are manufactured by the dry process,
the wet process, or the wet mechanical process. In the dry
process, which is suited to the manufacture of shingles or
other sheet products (B), a uniform thickness of dry materials
is distributed onto a conveyor belt, sprayed with water, and
then compressed against rolls to the desired thickness and den-
sity. The major source of process waste water is the water
used to spray clean the empty belt as it returns. The wet
process produces dense sheets, either flat or corrugated, by
introducing a slurry into a mold chamber and then compressing
the mixture to force out excess water. A settling and hardening
period precedes the curing process. The grinding operation
used to finish the sheet surface produces a large quantity of
dust which may be discharged with the process wastewaters. The
wet mechanical process, which is also used for asbestos-cement
pipe manufacture (A), utilizes willowed asbestos fiber which is
conveyed to a dry mixer where it is blended with the cement,
silica, and filler solids. The mixture is transferred to a
wet mixer or beater, and underflow solids and water from the
save-all are added to form a slurry which is pumped to cylinder
vats for deposition onto horizontal screen cylinders. The
resulting layer from each cylinder, usually from 0.02 to .10
inch in thickness, is transferred to an endless belt conveyor
for further processing. Flow diagrams for the wet mechanical
8-23-2
-------
process for pipe manufacture and the dry process for sheet
manufacture are shown in Figure 8-23-1. Asbestos-cement
plants recycle the majority of their water as a means of
recovering all usable solids. The save-all overflows may
be discharged from the plant as effluents or treated and
returned to the plant for whatever use its quality justifies.
This includes water for saws, vacuum pump seals, cooling,
hydrotesting, or make-up water for plant startup.
Asbestos Paper (C, D)
Asbestos paper is manufactured on machines of the Fourdrinier
and cylinder types which are similar to those which produce
cellulose paper. A mixing operation combines the asbestos
fibers with the binders and other minor ingredients. A pulp
beater or hollander mixes the fibers and binder with water into
a stock which is diluted to as little as one-half percent fiber
in the discharge chest. The discharge chest deposits a thin,
uniform layer of stock onto an endless moving wire screen. A
major portion of the water is drawn by suction boxes or rolls
adjacent to the sheet of paper.
The sheet is then transferred to an endless moving belt and
pressed to bring the paper to about 60 percent dryness. This
is followed by calendering, to produce a smooth surface, and
winding of the paper onto a spindle. The manufacturing process
is shown in Figure 8-23-1. The majority of the water in a
paper plant serves as an ingredient carrier and continually
recirculates in a loop through the machine and the save-all.
Occasionally, the solids from the save-all must be discharged
from the plant due to a product change, rapid setup of the binder,
or a plant shutdown.
Asbestos Millboard (E)
Asbestos millboard is produced on small cylinder-type machines
similar to those used for making asbestos-cement pipe (A).
The machines are equipped with one or two cylinder screens,
conveying felt, pressure rolls, and a cylinder mold. After
mixing and stirring, the slurry is transferred to a stock chest
where it is diluted and pumped to the cylinder vats with large
screens. The slurry flows through the screens, depositing a
mat of fiber on the cylinder surface before flowing out through
the ends of the cylinder. The mat is transferred to a carrier
belt. Pressure rolls then remove water from the mat as it is
wound onto the cylinder mold. Finished millboard usually
contains 5 to 6 percent water. Most of the water in the manu-
facturing process serves as an ingredient carrier and continu-
ally circulates in a loop through the machine and the save-all.
Excess overflow water must be discharged from the plant.
8-23-3
-------
Asbestos Roofing (F)
Figure 8-^23^1 shews the process flow diagram for asbestos roof-
ing manufacture. Asbestos paper is pulled through a bath of
hot coal tar or asphalt. After saturation, the paper passes
over a series of hot rollers to set the coal tar or asphalt in
the paper. After passing over cooling rollers, the roll of roof-
ing is coated with various materials to prevent adhesion between
layers. The roofing is finally air dried, rolled up, and pack-
aged for marketing. Water is used in two ways. It is converted
to steam to heat the saturating baths and hot rollers and for
cooling the hot paper after it has been saturated. The only
process wastewater is that originating in the spray cooling
and, in many cases, this contaminated contact water is dis-
charged with the clean non-contact cooling water.
Asbestos Floor Tile (G)
The tile manufacturing process involves several steps:
ingredient weighing, mixing, heating, decoration, calen-
dering, cooling, waxing, stamping, inspecting, and packaging.
The ingredients are weighed and mixed dry. Liquid constituents,
if required, are then added and thoroughly blended into the
batch. After mixing, the batch is heated to about 150°C
and fed into a mill where it is joired with the remainder
of a previous batch for continuous processing through the
rest of the manufacturing operation. Water serves only as
a heat transfer fluid. Non-contact cooling water remains
clean and can be reused continually if cooling towers or
water chillers are available to remove the heat picked up
from the hot tile. Leakages from various sources collect
dirt, oil, grease, wax, ink, glue, and other contaminants.
Textiles (H), Solvent Recovery (I), Vapor Absorption (J),
and Wet Dust Collection (K)
The products covered by the above four subcategories can be
grouped into three types: Asbestos textile products, friction
materials, and asbestos-containing gaskets, packings, and seal-
ing devices. In most plants in these subcategories, water is
not used in the manufacturing processes. However, process-
related wastewaters are generated in a few plants by manufactur-
ing operations or by air pollution control equipment. The
basic manufacturing processes and the origin and nature of
wastewaters for each of the three product types are outlined
below. A process flow diagram for the manufacture of various
asbestos textile products is shown in Figure 8-23-2. Asbestos
fibers are received by railcar in 100-pound bags. The fibers
are cleaned over vibrating screens or trommel screens. After
preparation, the fibers are mixed and blended. The fibers are
then arranged by thousands of needle-pointed wires which cover
the cylinders of a carding machine. The resulting continuous
8-23-4
-------
Wet Mechanical Process
Asbestos-Cement Pipe (A)
Dry Process
HATER
STEAM
WATER
Asbc:
RAW MATERIALS
STORAGE
PROPORTIONING
DRY MIX
ir
1
RAW MATERIA
STORAGE
PROPORTIONIN
DRY MIX
RECYCLE DJSOLIDS _
RECYCLED WATER ^ ...A WATER
4.4, K ^ "T" " ±
1 WET MIX
$~
| FORMING
*
CLARIFICATION _| . .
(SAVE-ALL) ROLLING
T I
1 g> SLUDGE
CUTTING
STFAM
CURING
(AUTOCLAVE)
PIPE END
FINISHING
!"&
KB > B^. SOLIDS
RECYCLED F.NISHING
4. WATER bTORAGE
HYDROSTATIC
TESTING
1 FINISHING
STORAGE
*
CONSUMER
,tos Paper (C. D)
RAW MATERIALS
STORAGE
PROPORTIONING
WATER
WATER
STEAM
WATER
4
ASBESTOS P
STORAGI
RECYCLED SOLIDS HOT COAL TAR
F RECYCLED WATER ,. ...[V YHmi OR ASPHALT ^r
-S
G
p- ' 't> SOLIDS
B> CONDENSATE
ng (F)
kPER
j_.r- M jjr WAJII 1
Vvy | 1 SATURATION |- - «> FUMES
1 MIXING
STOCK CHEST
METERING
4-
CLARIFICATION --J STEAM
1 WATER J 1
1 »w v-rr . .
8 f^ j HEAT TREATMENT } > ^»°
^r ROOFING" 1 COATING
pAPtn
MACHINE
1
-*L
K
COOLING r
WATER 1
4r
J
| COOLING J_ ^ WATER
^
DRYING
STORAGE
^COOLING WATER
t>-CONDENSATE CUTTING
ROLLINC
PACKAGIN
STORACI
G
1 *
^T CONSUMER
CONSUMER
OR FIGUKE 8-23-1
HOOFING PLANT ASBESTOS
8-23-5
-------
RAW MATERIALS
STORAGE
FIBER PREPARATION
BLENDING
MIXI
X 1
, , 1
TWISTING SINGLE ~i
WISTED ROPE
1
1 BRAIDING 1
BRAIDED
ROPE
1
*
NG i
ING |
NG
^
ING 1
r
H
r
t
1 BRAIDING 1 /
t . ,
. RAYON. COTTON
j OR OTHER FBER
^ NON- WOVEN FELTS
LIGHT GAUGE WFE
PLIED YARNS METALLIC YARNS '
i i
i ^ THREAD
U COATNG L_ DRYING _^. TREATEC
" 1 ' OVEN YARNS
I^WASTE WATER
» TWISTING L^-TWISTED CORD
~*
LEAVING I
^f
I I
BRAIDED BRAIDED BRAIDED TAPE WOVEN CLOTH
TUBING CORD ROPE TUBING
SOLVENT
COATING
CLOTH
L
FABR
fASTE WATER
Figure 8-23-2
Asbestos Textile Manufacturing Operations (H)
8-23-6
-------
mat of material is divided into strips, or slivers, and mech-
anically compressed between oscillating surfaces into untwisted
strands which are then wound on spools to form the roving.
Roving is the asbestos textile product from which asbestos yarn
is produced. Asbestos twine or cord is produced by twisting
together two or more yarns on a spinning frame. Braided products
are made by a series of yarn-carrying spindles, half traveling
in one direction and half in the opposite direction to plait
the yarn together and form the braided product. Asbestos yarn
or cloth may be coated for fabrication into friction materials
and special products. Water is not normally used in an asbestos
textile manufacturing plant. Two exceptions are the addition
of moisture during weaving or braiding and the coating opera-
tion. Wastewater is generated in the latter process.
Friction materials may be further classified into the molded
products and woven products. Water is not used in the manufactur-
ing processes. Wastewaters are generated in a few friction
material plants in the solvent recovery operations and in the
wet dust collection equipment. Similarly, water is not used
in the manufacture of gaskets, packings, and sealing devices.
The manufacture of sheet gasket material may involve cooling
and solvent recovery operations, in which case process-related
wastewaters are generated.
4, Wastewater Characterization
Wastewater characteristics of process effluents from each of
the 11 subcategories of the asbestos manufacturing industry
are shown in Table 8-23-1.
5. Control and Treatment Technology
In-Plant Control
Significant in-plant control of both waste quantity and quality
is possible for most subcategories of the asbestos manufactur-
ing industry. Important control measures include the proper
storage of raw materials, segregation of wastewaters, good
housekeeping practices, and water conservation. Raw materials
should be stored indoors and kept dry. Sanitary wastes should
be disposed of separately from process wastes. In plants where
non-process wastes are combined with manufacturing wastes, a
careful evaluation should be made to determine if some or all
of these wastes could be segregated and recirculated. Fresh
water should be used first for pump seals, steam generation,
showers, and similar uses that cannot tolerate high contaminant
levels. The discharges from these uses should then go into the
manufacturing process as make-up water and elsewhere where
water quality is less critical. In line with water use prac-
tices, evaluation of the benefits of increased save-all capacity
should be made at some plants. This would provide more in-plant
water storage, permit greater operating flexibility, and reduce
the level of pollutant constituents in the raw wastewaters dis-
charged from the plant.
8-23-7
-------
TABLE 8-23-1
ASBESTOS MANUFACTURING DIDUSTBI
RAW WASTE CHARACTERIZATION
Parameter (DK/I)
ricv Sor.je
Ual.per day)
Flow Type
BC3 (=6/1)
TSS
IDS
00
1 ^-3
U) J>H
00 Oil Si Grease
AlialirJ.ty
BUK-sra
Phosphorus
Phenol
0
Ter^erature, C
AsV'ostos-Coroent
Pipe
A
COV-50CM
B
2
500
1000*
12.0-12.9*
700
2.?
0.05
>to
AsbeiJ tos-Curaent
Sheet
B
70K-5'lOM
B
2
850
1150*
ll.lt-12.U»
1000
50
Asbestos-Paper
(Starch Binder)
C
13CM-1.3MH
C
110
680
1220*
160
8.0
l.Z
16.0
0.25-1.0
Asbestos-
Paper
(Bias torn'- ric
D
130M-1.3KM
C
110
680
1220*
160
8.0
1.2
16.0
0.25-1.0
Asbestos
Millboard
E
80M-600M
B
5
35
7
8.3-9.2*
12-31
Asbestos
Hoofing
Products
F
375M
B
6-37
37-150
20-91
6.8-8.2
1.6
0.5
0.5
13
Asbestos
Floor Tile
0
10M-18OM
B
15
150
300
6.9-8.3
5.5
5.0
1.5
Coating, or
Finishdni! of
Asbestos
Textiles
H
200
E
Present
Present
Present
Variable
Solvent Vapor
Recovery Absorption
I J
10M 61':
C B
1125*
0-30 30
1930* I6oo»
6-9 >9*
12
Wet Dujt
Collection
K
50K-150X
B
Pr«eent
Pr«c«nt
6-9
Note: 3 - Batch Operation
C - Continuous Operation
y - Thousand
I-M - Million
* See Appendix 5 for parameters which may be inhibitory to biological syate:
-------
In some asbestos-cement pipe plants (A), water used in the hydro-
test operation may be completely recirculated. Consideration
should be given to piping wastewaters from wet saws to the save-
all systems. In the asbestos-cement sheet subcategory (B),
complete recirculation is possible most of the time. The manu-
facturing process may be so balanced that the fresh water intake
equals the amount of water in the wet product. Fresh water
enters the system only for boiler make-up and as part of the
vacuum pump seal water. In the asbestos-paper subcategories
(C, D) , partial recycle of water and underflow solids is attain-
able. Complete recycle on a continuous basis is possible in
asbestos millboard (E) if some provision is made for the release
of save-all overflow when upsets occur or product changes are
anticipated. In the roofing and floor tiles subcategories (F,G),
the possibility of eliminating the contact cooling water opera-
tions should be considered. Bearing leaks should be controlled
and escaping water protected from contact with wax, oils, glue,
and dirt. In any case, non-contact cooling water and conden-
sate should not be mixed with cooling water. In asbestos tex-
tile coating (H), the recommended control measure is the con-
tainment of wastes in undiluted form and containerization for
salvage or land disposal. Dry cleaning techniques should be
substituted for wet methods. In addition, measures should be
taken to eliminate or contain spills and dripped materials.
Since recovery of the solvent is not a goal in vapor absorp-
tion (J) , an incinerator could be utilized to remove
the vapor from the exhaust air. The use of an incinerator
would eliminate the wastewater discharge in this subcategory.
In wet dust collection (K), if wastewater treatment beyond sed-
imentation is indicated, the possibility of substituting dry
dust collectors for the wet scrubbers should be investigated,
thereby eliminating the discharge of wastewater in this sub-
category .
Treatment Technology
The process wastewaters from the manufacture of asbestos-cement
pipe (A), asbestos-cement sheet (B), and millboard (E) represent
the major source of pollutant constituents in the asbestos
manufacturing industry. The wastes originate from several
points in the manufacturing processes but are usually combined
into a single discharge from the plant. The various waste-
water treatment practices for each of the subcategories are sum-
marized in Table 8-23-2.
8-23-9
-------
POLLUTANT AND METHOD
BOD
1. Sedimentation and
Coagulation
TABLE 8-23-2
ASBESTOS MANUFACTURING INDUSTRY
WASTEHATER TREATMENT PRACTICES
REMOVAL EFFICIENCIES (Percent)
Asbestos-Cement Asbestos-Cement Asbestos Paper Asbestos Paper Asbestos Asbestos Asbestos
Pipe Sheet (SB) (EB) Millboard Roofing Floor Tile
A B c D E __T G
Coating or
Finishing of Solvent Vapor Wet Dust
Textiles Recovery Absorption Collection
!_ _J_ X
00
I
10
u>
r
2. Dilution and Lagoon
COO
1. Sedimentation and
Filtration
2. Sedimentation and
Coagulation
3. Carbon Adsorption
Suspended Solids
75
97
97
1. Sedimentation and
Gravity Thickening
2. Sedimentation and
Coagulation
3. Sedimentation and
Filtration
95
1. Neutralization
Effluent level
-------
RUBBER
1. General Industry Description
The rubber processing industry includes the manufacture of
tires and inner tubes, synthetic and reclaimed rubber, molded,
extruded, fabricated and latex-based products. Each of
the above segments of the industry requires varying services
and raw materials.
The rubber processing industry has the following Standard
Industrial Classification (SIC) numbers: 2822, 3011, 3021,
3031, 3041, 3069, 3293, 7534.
2. Industrial Categorization
The rubber processing industry is broadly subdivided into
three main categories: tire and inner tube industry, synthetic
rubber industry, and fabricated and reclaimed rubber industry.
The waste volumes, waste loads and significant pollutants-
vary with the operation being conducted and the raw materials
used. For the purposes of raw waste characterization and
delineation of pretreatment information, the industry is
further subdivided into 11 subcategories, as shown in Table
8-24-1. The code letters shown after the subcategories are
used to identify them throughout this section. The general
molded, extruded, and fabricated rubber products segment has
been subcategorized by facility size, as determined by usage
of raw materials.
3. Process Description
Tire and Inner Tube (A)
Today's tire manufacturer produces many types of tires designed
for a multitude of uses. General product categories include
passenger, truck and bus, farm tractor and implement, and
aircraft. Basically, the tire consists of five parts, namely:
the tread, the sidewall, the cord, the bead, and the inner
liner. Basic tire ingredients are synthetic rubbers, natural
rubber, fillers, extenders and reinforcers, curing and accele-
rator agents, antioxidants, and pigments. The typical tire-
manufacturing process consists of the following:
1. Preparation or compounding of the raw materials;
2. Transformation of compounded materials into the five
t ire components;
3. Building, molding, and curing of the final product.
8-24-1
-------
TABLE 8-24-1
RUBBER PROCESSING
Main Category
1. Tire and Inner Tube
2. Synthetic Rubber
3. Fabricated and
Reclaimed Rubber
Subcategory
Tire and Inner Tube (A)
Emulsion crumb rubber (B)
Solution crumb rubber (C)
Latex rubber (D)
Small-sized general molded,
extruded and fabricated
rubber plants (E)
Medium-sized general molded,
extruded and fabricated
rubber plants (F)
Large-sized general molded,
extruded and fabricated
rubber plants (G)
Wet digestion reclaimed
rubber (H)
Pan, dry digestion, and
mechanical reclaimed rubber (I)
Latex-dipped, latex-extruded
and latex-molded rubber (J)
Latex foam (K)
8-24-2
-------
The flow diagram for a typical tire plant is shown in Figure
8-24-1. The Banbury mixer and the roller mill are the basic
machinery units used in the compounding operation. Fillers,
extenders, reinforcing agents, pigments, and antioxidants
are added and mixed into the raw rubber stock. Non-reactive
rubber stdck, which contains no curing agents, has a long
shelf life and may be stored for later use. The reactive
rubber stock, which contains curing agents, has a short shelf
life and must be compounded and used immediately.
Carbon black and oil are added to the rubber in the compound-
ing operation. After mixing, the compound is sheeted out in_
a roller mill, extruded into sheets or pelletized. The ~
sheeted material is tacky and must be coated with a soapstone
solution to prevent sticking.
The sheeted rubber and other raw materials, such as cord and
fabric, are then transformed into one of the basic tire com-
ponents by several parallel processes. The tire is built up
as a cylinder on a collapsible, rotating drum. The uncured
tires are sprayed with release agents before molding and cur-
ing in an automatic press. After the molding and curing opera-
tion, the tire proceeds to the grinding operation where the
excess rubber which escaped through the weepholes is ground
off. For whitewall tires, additional grinding is required to
remove a black protective strip, followed by a protective coat
of paint. After inspection and possibly final repairs, the
tire is ready to be shipped.
Inner tube manufacture is very similar to tire manufacture and
consists of the same three basic steps: compounding of raw
materials, extension of compounded materials, and the building,
molding and curing operations to form the final product. One
distinction of inner tube manufacture is the high usage of
butyl rubbers. A flow diagram of a typical inner tube plant
is shown in Figure 8-24-2.
Wastewater contaminants from the tire and inner tube industry
are: oils from run off, roller mills, hydraulic system, and
presses; organics and solids from Banbury seals, soaptone dip
tank, dipping operation, spray painting operation, and air
pollution equipment discharges; and solvent based cements from
the. cementing operation.
8-24-3
-------
««STE«ATER
FIGURE 8-24-1
TIRE AND CAMELBACK PRODUCTION FACILITY (A)
RUBBER INDUSTRY
-------
00
1
to
ifct
1
Ul
CARBON
BLACK
STORAGE
RUBBER
AND DRY
COMPOUND *
STORAGE
EXTENDER
GIL +
STORAGE
COOLING-WATER , ^
RETURN ^
COOLING COOLING
' 'Ld -^- TnFITUFH
* COOLING WATER "' TOWER Q
**TER fl RAW INTAKE
WATER
1 |
SLOWDOWN REGENERATION
1 WASTE
' 1
WASTEWATER USTEWATER
t
TUBE FORMATION:
COMPOUNDING ^ M|us TUBE
MILLS STOCIt COOLING '^7$ «"LUING
TIU» TUBES AND
1 niBiMf,
I I->COOLING j 'Alfl
WAILR J kUULIHbl | 1 MIcAM
, WATER ^ j
-^WASTEWATER ' n*»lt-^r icmpc
WASHOOWN LEAKAGE WATFB LEAK'CE
PRODUCT
PACKAGING AND
SH IPHI Nli
, vicunnwy HAiiniUHN
-TING "ASH P CONDENSATE
SOAPSTONE »*TER »
SOLUTIOHS .7 1
SPI'LLS
RUNOFF
WASTEWATER
""<"">" pn||FP
! , SUPJvLY
"ILLS <;TFAH
LEAKAGE 6LOWOOWN
WASHOOWN !
* ^
WASTEWATER WASTEWATER
I-4*
WATER RAW
TREATMENT IHTAKE
REGENE'RATIOD WTER
WASTE)
WASTEWATER
FIGURE 8-24-2
INNER TUBE (A)
RUBBER INDUSTRY
-------
Emulsion Crumb Rubber (B)
Polymerization in emulsion is one of the most common process-
ing techniques to produce synthetic rubber. Figure 8-24-3
shows the process flow diagram for the continuous production
of crumb styrene-butadiene rubber (SBR), the principal synthetic
rubber, by the emulsion polymerization process. Styrene and
butadiene (monomers) are piped to the plant and the inhibitors
are removed by caustic scrubbers. Soap solution, catalyst^
activator, and modifier are added to the monomer mixture prior
to entering the polymerization reactors. The reactor system
is capable of producing either "cold" (40-45 F, 0-15 psig) or
"hot" (122°F7 40-6- psig) rubber. The product rubber is
formed in the emulsion phase of the reaction mixture. The
product is a milky white emulsion called latex. Short stop
solution is added to the latex leaving the reactors to stop
polymerization at the desired conversion. The unreacted
monomers are stripped from the latex and recycled to the feed
area. An antioxidant to protect the rubber from attack by
oxygen and ozone is added to the stripped latex in a blend
tank. The latex is now stabilized, and different batches,
recipes or dilutions can be mixed. After coagulation, screening,
rinsing and dewatering, the rubber crumb is finally dried,
pressed in bales and stored prior to shipment. Wastewater
contaminants from the emulsion polymerization process are:
dissolved and separable organics from monomer recovery,
crumb dewatering, monomer stripping and tanks and reactors;
uncoagulated latex from tanks, reactors, and monomer stripping;
and suspended and dissolved solids from coagulation, crumb
dewatering, monomer stripping, and reactors.
Solution Crumb Rubber (C)
The production of synthetic rubber by solution polymerization
is a stepwise operation, and, in many aspects, is very similar
to emulsion polymerization (B). However, solution polymerization
requires extremely pure monomers and the solvent (hexane, for
example) should be completely anhydrous. Moreover, in contrast
to emulsion polymerization, where the monomer conversion is
approximately 60 percent, solution polymerization achieves
conversion levels which are typically in excess of 90 percent.
Wastewater contaminants are: dissolved and separable organics
from solvent purification and monomer recovery; suspended and
dissolved solids from crumb dewatering; and high alkalinity
from caustic scrubbers.
Latex Rubber (D)
Latex production follows the same processing steps as emulsion
crumb production with the exception of latex coagulation, crumb
rinsing, drying and baling. The polymerization is carried out
to 98 to 99 percent conversion levels. As a result, monomer
8-24-6
-------
CO
I
N)
*>.
I
SPILLS
"liiaioeW
nun mi
FIGURE 8-24-3
EMULSION CRUMB RUBBER PRODUCTION FACILITY (B)
RUBBER INDUSTRY
-------
recovery is not economical and the process is directed towards
maximum conversion on a once-through basis. The nature and
origins of principal wastewaters are: dissolved and separable
organics from excess monomer stripping, reactors and tank cars;
suspended and dissolved solids from reactors, strippers, tank
cars and tank trucks; and uncoagulated latex from reactors, tank
cars and tank trucks.
General Molded, Extruded, and Fabricated Rubber Plants (E, F, G)
Product categories in the general molded segment include battery
parts, seals, packing, heels, shoes, medical supplies, druggist
supplies, stationery supplies, etc. General extruded products
includes belting and sheeting. Product types in the general
fabricated segment are rubber hose, footwear, friction tape,
fuel tanks, boats, pontoons, life rafts and rubber clothing
and coated fabrics, etc.
During the molding of rubber products, the rubber is cured as it
is shaped. Curing (often referred to as vulcanization) is an
irreversible process during which a rubber compound, through a
change in its chemical structure, becomes less plastic and
more resistent to swelling by organic liquids. In addition,
elastic properties are conferred, improved, or extended over
a greater range of temperature. The principal methods used
for the manufacture of general molded products are the com-
pression, transfer, and injection molding processes. All three
of these processes may be in use at one plant location. The
processes typically consist of compounding of the rubber stock,
preparation of mold preforms, molding, and deflashing. A process
flow diagram for a typical molding operation is shown in
Figure 8-24-4. The nature and origins of wastewaters are: oils
from curing presses, compounding and pick-up by storm run-off;
solids from soapstone dip tank and wet air pollution equipment
discharges; rubber fines from rinse water; and anti-tack agents
from cooling water overflow.
Manufacture of sheeting and belting serves as a good example
of the production methods for extruded items. The rubber
stock is compounded on a Banbury mixer or compounding mill.
After compounding, the rubber is worked on a warm-up mill and
fed to the extruder. The extruded rubber is produced as sheets.
In some cases, the extruded or calendared rubber is dipped in
soapstone slurry for storage. Belting or extruded sheeting is
8-24-8
-------
RUBBER STOCK
ORIPPAGE
LEAKAGE
WASTEWATER
RUBBER.
PIGMENTS
AND MIX
COMPOUNDS
STORAGE
COOLING
WATER
MOLDED PRODUCT
COOLING AND
RINSE WATER
I
RUBBER STOCK
OIL
LEAKAGE
1
*
WASTEWATER
TRANSFER BLANK
SPILLS
LEAKAGE
i
T
dASTEWATER
COOLING AND
RINSE WATER
1
*
kASTEWATER
RUBBER STOCK
TRANSFER
MOLDS
i
OIL
LEAKAGE
I
i
KASTEWATER
I
EXCESS
BLANK
SOLID
WASTE
tt L9EO PRODUCT
DEFLATING
SYSTEKl
1
INJECTION
MOLDS
FLAStl
SOLID
WASTE
MOLDED PRODUCT
M0LOEO
PRODUCT
FINISHING
PRODUCT
INSPECTION.
PACKAGING &
SHIPMENT
COOLING
'WATER
I
i
OIL
LEAKAGE
WASTEWATER
_ *
-COOLING
PERIODIC
SOLVENT
DISPOSAL
FLOW DIAGRAM FOR
r-^N4Of A TYPICAL MOLDED ITEM (E,F,G)
-------
cured using a rotacure or press curing technique. The nature
and origins of wastewaters are: oils from machinery, calendering,
extrusion, compounding, and storm run-off from storage area;
solids from the anti tack agent and tank and wet air pollution
equipment discharges; organics and lead from steam vulcanizer
condensate; and cooling water.
Hose production provides a good example of the fabricated rubber
manufacturing processes. Figure 8-24-5 illustrates the process
flow diagram for the manufacture of typical hose items. The
nature and origins of wastewaters contaminants are: oils from
machinery,compounding, and storm run-off; solids from soapstone
dip tank, ply formation and latex storage; dissolved organics
from ply formation, shoe building, and latex storage; and anti-
tack agents from cooling water overflow.
Wet Digestion Reclaimed Rubber (H) and Pan, Dry Digestion and
Mechanical Reclaimed Rubber (I)
Reclaimed rubber is prepared primarily from scrap tires and
scrab inner tubes. Three basic techniques are used to produce
reclaimed rubber: the digester process, the pan process, and
the mechanical process. A generalized process flow diagram for
the three processes is shown in Figure 8-24-6. Broadly, the
reclaiming process can be divided into three major components,
two of which are mostly mechanical and the third predominantly
chemical. By far the most important source of raw material is
tire scrap. The rubber scrap is separated and ground, then
given heat treatment for depolymerization, and finally processed
for intensive friction milling. All three processes employ
similar rubber-scrap separation and size-reduction methods.
They differ in depolymerization and the final processing steps.
The nature and origins of wastewater contaminants are: oil
from depolymerization, blowdown tank, dewatering, dryers and
compounding; solids, caustics and organics from depolymerization,
defibering, dewatering and soapstone dip tanks; and fibrous
material removed from tires.
8-24-10
-------
STRIPPED LEAD FOR RECYCLE
DRIPPING
LEAKAGE
I
WASTEWATER
DRIPPING
LEAKAGE
+
(lASTERKATER
HOSE
REINFORCING
CO
I
to
COOLING
HATER
FROM /
SHEATH AND T*
WRAP REMOVAL'
LLJ
ZD
1
U-l
az.
0=
CD
| MANDRALS
*
INSERTION
1
COOLING
WATER
OVERFLOW
WASTEWATER
MANDREL
REMOVAL
*
co
w;
ov
WAS
INSPFHTION
HYDRAULIC , BRANDING.
TESTING STORAGE
TO
HANOREL
REMOVAL
I
COOLING
WATER
OVERrLO*
LEAD SHEATH
COOLING WATER
WASTEWATER
STEAM CONDENSATE
I
VlASTEWATER
TEST
WATER
I
WA^TERWATER
FIGURE 8-24-5
FLOW DIAGRAM FOR THE PRODUCTION OF TYPICAL HOSt STEMS (INCLUDING REINFORCED TYPES) (E,F,G)
-------
00
I
MECHANICAL RECLAIM PROCESS
FINE
FINE GROUND DEFIBEREO SCRAP ^ MECHANICAL DEVULCANIIED SCRAP ^
GRINDING ' DEPOLYMERIZATION
RUBBER ^
SCRAP "~~^
1
STEEL-BEL TEO
i. STUOOEO
TIRES! COOL
1 HATEf
SOLID *iSTE
l
DEPOLYHERIZA
.AND OEFIBERI
AGENTS AND 0
1
SPILLS
NASHDOWN
»ASTE«ATE
T '
COOLING 1
ViATER *
a:
v>
UJ
UJ
or
UJ
oa
u_
GRINDING GROUNO , 1
CRACKER MILLS SCRAP OEFIBE
MAGNETIC - -» I'AMHC
SEPARATORS _to , AIR T
tl ' METAL HBtH
I ,Fm SCRAP SCRAP SE
Nr_l ttAKS itKAr i ae.
1 N A^tHfiniVM J. w ^
T r.orr *ASTE ^
*ASTE*ATER hftSTE £
cc
UJ
PROCESS ^
. , ^ WTffl 1
r
LEAKS
I tKASTEUTER
OEPOLYMERIZATION
OILS AND AGENTS
1
LEAKS VAPOft
VFN T
i A , , .COOLING
*ASTE»ATER PROCESS f **""
HATER
Fl BER ! ' .,,....
..,,. FREE ,,,, CtWPOUNBING: PRODUCT
' ^f*R AP ~~" "~* U i ycoc c TflOifif
mi r^ iii - - - - MILLS -NU
'BLt;> , , t 1 STRAINERS STORAGE
LUU L 1 Mi _J t -p - - . -
U»TCD « J or 1 LLi i i i
*RUR LEAKS S '
, ±1 LEAKS
KASTEKATER o <=
_-» UJ ^
O C3
PROCESS *ATEh f VAPOR VENT VAPOR VENTA 1
1 OEtlATERED T
DEVULCANIZEO 1 1 DEVULCANI7Fn i 1 nFUIII r.lNI 7fn
\CW Jn|,r*Trn| RUBBER SLURRY, BLO»DO».N RUBBER SLURRY ^"J^"^- RUBBER ^
LS ^ ' PRESSES ...- J
1
DIGESTER
LIQUOR
! »
»ET DIGESTER RECLAIM PROCESS WASTEKiATER
NOTE: SOME RECLAIMING FACILITIES OPERATE BORE THAN ONE TYPE OF PROCESS
FLOW DIAGRAM OF TYPICAL MECHANICAL, PAN (HEATER), AND WET DIGESTER RECLAIM PROCESSES (H,I)
Figure 8-24-6
-------
Latex-Dipped. Latex-Extruded and Latex-Molded Rubber (J)
and Latex Foam (K)
To manufacture sundry rubber goods from latex compounds, it is
necessary to convert the compounds into solids of desired
form. The latex is compounded with various ingredients, such as
antioxidants. Several manufacturing processes are used for
fabricating different types of rubber goods from latex mixtures.
The process diagrams for a typical latex-based dipped item and
a latex foam item are shown in Figures 8-24-7 and 8-24-8
respectively- Principal wastewater contaminants for the latex-
dipped, latex-extruded, and latex-molded rubber are suspended
solids, dissolved solids, oil and surfactants. An important
additional contaminant for the latex foam is zinc.
4. Wastewater Characterization
Wastewater characteristics of total effluents from each of the
11 subcategories of the rubber processing industry are shown
in Table 8-24-2.
5. Control and Treatment Technology
In-plant Control
Significant in-plant control of both waste quantity and quality
is possible for most subcategories of the rubber processing
industry. For tires and inner tubes (A), in-plant control
includes the proper handling of soapstone, latex dip, and dis-
charges from air pollution control equipment. A closed-loop
recirculation system eliminates the continuous discharge of
large quantities of soapstone. Alternatives to recirculation
include the discharge of soapstone directly to the process
sewers or the use of substitute solutions which require the
system to be cleaned on a less frequent basis. A common
practice among the larger manufacturers is to eliminate the
latex dipping operation from the tire facility. In plants that
still dip fabric, an effective control measure is to seal off
drains, supply the area with curbing, and drum the waste
solutions for landfill disposal. The solids from the wet
scrubber discharge in the tire-finishing area can be settled
out in a sump. The particulates are large, and with a properly
designed separator, the clarified water can be completely
reused. Further in-plant measures for the tire and inner tube
industry include the control of spills and leakage by providing
curbing and oil sumps, the use of dry sweeping equipment for
8-24-13
-------
00
I
*>.
I
RINSE
HATER
*
PRODUCT
RINSE
1
PRODUCT
onmiG
OUSTING
fiCKACI'IG
SPENT
niWSE
*A!Ef,
HASTEnATER
I I COOLING
SPILLS ' »«ATER
LEAKS
r
i
ASTElATER
I COOLING
IATER
1
SPENT
RINSE
WATER
tiASTEnATEl!
WASTEiATER
SPILLS
LEAKS
TrASIiDOWN
Figure 8-24-7
FLOW DIAGRAM FOR THE PRODUCTION OF TYPICAL LATEX -BASED DIPPED ITEMS
(J)
-------
. COHDUSER
COaiUG
IUER
COHOtHSEB
t
CtHPOUKOINC INO
CIIIING HENIS
oo
M
*»
I
M
UI
eouointut
IISTEIITE*
111(1
nonce
FREEZE
CIOIIDE *
CIS
PRODUCT
STOFIEE
1*0
Foil
DRTIIIC
CLEIN
>IIER
SUPPLY
FOIH
1
tlTEH
HIPOR
LITEI
COKCCKTRIIIOK
II
EVIPORMIOII
KTE1
IKIlBHEnUIE
LITEI
1
SPILLS
flSHOOM
1
ISTEI1TER
~
1
fOIH
HIKSIKC
STEPS
t*j
oc
or
^
k
i
FOU
STEPS
I
FUJI rHODVCl
LITEI
CODPOUHOIIIIi
s
1
SPIUS
IISHU9
IISIEII
FOIV
CUAIKC
PRESSES
SPILL
ISHO
1
!
Id
Bill KILL
CIOBKD CBUBIKC OF
cn«POu«oi«c '"csfsifnis
ICEMTS
u
» SPILLS
LEIKS
TEH ^
n:Hoem
CIRION
CIS
IINSE
»ISTE«UE»
COOUHC
I
-------
TABLE 8-2k-2
RUBBER PROCESSING IHDUSTRY
RAW WASTEWATER CHARACTERIZATION
Wet
Pan, Dry
Latex-dipped,
Digestion & Digestion & Latex-extruded
Parameter (mg/1)
Flow Range
(gallons per day)
Flow Type
BOD5 (mg/1)
TSS
IDS
COD
Oil
Lead
Surfactants
Zinc
Tire &
Inner Tube
A
0.2MM-22.22MM
0. 2-31
9-1065
0-757
0-298
1-96*
Emulsion
Crumb
B
1.1^-1,3^
C
115-183
12l*-770
528-1886*
7-191*
Solution
Crumb
C
.21MM-2.75MM
C
10-123
18-1*51
50-1168*
8-195*
Small-Sized
Latex Rubber
Rubber Plants
D E
.l8l*5-. 226MM 1.5M-6.27M
377-U8 l*-2l*
1*50-1*70 1-9
38l*-657
2l*l*0*-2790* 3-20
28 1-26
Medium-Sized
Rubber
Plants
P
ai*M-285.^
10-21*
1-13
607-790
20-50
.8-7
.008
Large-Sized
Rubber
Plants
G
.ll*MM-1.92MM
6-28
10-62
213-3,100*
57-261
1*.6-31
0-8.0*
Mechanical
Reclaimed
Rubber
H
1.32MM
10
21
132
52
k.-f
Mechanical
Reclaimed
Rubber
I
.891*5
7.2
16.6
101*
37.6
2.8
& Latex-
Molded
Rubber
J
2,.5M-^
133-152
78-3019
385-111*6*
176-678
6-129*
1.8-6.1*
Latex
Foam
K
*
1155*
1*92
1353*
1*285*
571*
5.1
200*
Note: M - thousand
SIM - million
C - continuous process
* See Appendix 5 for parameters which may be inhibitory to biological systems.
Data shown is from exemplary plants, and may not be typical of all plants In the industry.
-------
prevention of process-area washdowns from contaminating waste-
waters, and the diking of all oil-storage areas to prevent
contamination of wastewaters by oil spillages.
Since the synthetic rubber industry (B, C, D) is highly tech-
nological and involves numerous* proprietary and confidential
processing techniques, many of the significant control methods
would call for radical changes in the processing or product
quality and are, therefore, not feasible. However, some
potential exists in the control of crumb rinse overflow, coagu-
lation liquor overflow, vacuum systems seal water, carbon black
slurries, latex spills and baler oil leaks. Reduction of COD
levels in the synthetic rubber wastewaters through the use of
activated carbon technology is also feasible.
In-plant control measures for the general molded, extruded,
and fabricated rubber subcategories (E, F, G) require proper
handling and isolating general spills and leaks of soapstone
and other anti-tack agents, latex compounds, solvents and
rubber cements, metal preparation wastes, and air pollution
control equipment discharges. Contamination by machinery oils,
greases and suspended solids can be reduced by blocking of
floor drains, removing oil leaks promptly with dry absorbent
granules and by curbing the problem area. The spillage of
soapstone and other anti-tack solutions can be controlled by
similar methods. An effective way to handle latex is the use
in latex drums of plastic liners which can be discarded when
the drum is reused. Latex spills around storage and transfer
facilities are coagulated with alum and scraped from the ground.
Solvents and rubber cements should be mixed and stored in areas
without floor drains to control spills and leaks. If acid
pickling is used to prepare metal components, precipitation of
metals and pH adjustment should be carried out. The pickling
wastes can also be containerized and hauled from the plant.
In the wet digestion reclaimed rubber subcategory (H), signifi-
cant in-plant control measures include the defibering of scrap
rubber by mechanical or physical techniques as an alternative
to chemical defibering and the return of process oils and
digestor liquor. Return of process oils and the control of
vapor condensates and spills and leaks are significant in-plant
measures for the pan, dry digestion and mechanical reclaimed
8-24-17
-------
rubber subcategory (I). In the latex-based products subcate-
gories (J, K), prevention of latex spills and leaks,and reduction
in the volumes of foam rinse waters and cleaning wastes
by employing countercurrent rinsing, constitute the most sig-
nificant in-plant control measures.
Treatment Technology
The various wastewater treatment practices for each of the 11
subcategories of the rubber processing industry are summarized
in Table 8-24-3. The removal efficiencies shown pertain to the
raw waste loads of process effluents from each of the subcategories,
8-24-18
-------
Pollutant and Method
Tire & Inner
lube
A
Emulsion
Crumb
Rubber
B
Solution
Crumb
Rubber
C
TABLE 8-214-3
RUBBER PROCESSING INDUSTRY
WASTEWATER TREATMENT PRACTICES
Removal Efficiency (Per Cent)
Latex
Rubber
D
Small
Converter
Medium
Converter
F
Large
Converter
G
Wet
Digestion
H
Dry
Digestion
I
Latex Foam
K
BOD
1.
2.
3.
k.
Sedimentation and Holding Lagoon
Recirculation of Soapstone
Coagulation, Clarification
Coagulation, Settling, Activated
Sludge
Coagulation, Clarification, Zinc
Precipitation, Clarification
76-83
82
99
81
81
70
51
86
65
COD
i
10
1. Sedimentation and Holding Lagoon
Recirculation of Soapstone
2. Coagulation, Clarification
3. Coagulation, Settling, Activated
Sludge
k. Oil Separator and Holding Lagoon
62-87
72-7^
78
52
80
76
Oil and Grease
1. Sedimentation Recirculation of
Soapstone
2. Gravity Separator
3. Coagulation, Clarification
k. Coagulation, Settling,
Activated Sludge
96
60
91
99
95
99.8* 93
28
Suspended Solids
1. Coagulation, Clarification
2. Equalization, Activated Sludge
3. Settling, Stabilization Lagoon
if. Gravity Separator
5. Coagulation, Clarification, Zinc
Precipitation and Clarification
89
80
83
89-9^
81
62
73
72
99*
82
90
Note:
*Values indicated reflect reductions due to recycle
as well as wastewater treatment.
-------
TIMBER
1. General Industry Description
The Timber products processing industry includes a broad spec-
trum of operations ranging from cutting and removing the timber
from the forest, to the processing of the timber into a wide
variety of finished products.
Establishments engaged in this industry are included in Standard
Industrial Classifications (SIC) 24 and 25.
2. Industrial Categorization
This industry has been divided into the following subcategories:
Subcategory Designation
Barking A
Veneer B
Plywood C
Hardboard-Dry Process D
Hardboard-Wet Process E
Wood Preserving F
Wood Preserving-Steam G
Wood Preserving-Boultonizing H
Wet Storage I
Log Washing J
Sawmills and Planing K
Finishing L
Particleboard M
Insulation Board (subject to change) N
Insulation Board with Steam or
Hardboard Production O
Wood Furniture and Fixture Production
without Spray Booths or Laundry
Facilities Q
Wood Furniture and Fixture Production
without Spray Booths but with Laundry
Wood Furniture and Fixture Production
with Spray Booths, without Laundry
Wood Furniture and Fixture Production
with Spray Booths, with Laundry
Process Descriptions
Figure 8-25-1 contains a product manufacturing flow diagram
for the timber industry, which includes the subcategories dis-
cussed below.
8-25-1
-------
FURNITURE
MANUFACTURE
i
^PULP AND PAPER
k
BBS« sffir,, r° ,
f u A LJ«* YK n YIUV \ TRUCK D W t 1 U t L> n
(HARVfSTEDT.««> RA|LQR c . WATER STORAGE
1
^
. COKES
1 CORES
BARK REMOVAL
o. HYDRAULIC
b. MECHANICAL
, ROUND WOOD ^ ,
.. 1
. SAW MILLS AND ':
' PLANING MILLS
PLYWOOD CH1MAMO
SAW DUST 1 '
1
1 1
HARDBOARD
0- WET PROCESS
b.DRY PROCESS
1 '
^ PLANCH | I
^ SHAVINtS 1
i
i
INSULATIO
BOARD
t .
I 1 W
PLYWOOD ^
O.MAT
IRD
£j LUMICM
FINISHING AND
MISCELLANEOUS
OPERATIONS
1
FIGURE 8-25-1
INTERRELATIONSHIPS OF THE TIMBER PRODUCTS INDUSTRY
8-25-2
-------
Barking (A) - The barking subcategory includes operations which
involve the removal of bark from logs. Barking may be accomplished
by several types of mechanical abrasion or by hydraulic force.
Types of barking machines include: drum barkers, ring barkers,
bag barkers, hydraulic barkers and cutterhead barkers. The
hydraulic barker uses a high pressure water jet to blast bark
from the log. Large volumes of water are required for this
operation, and large volumes of wastewater are produced. Due
to the high quality water requirement of the operation, water
recycle is not usually practiced at the present time.
The remaining barkers remove bark by milling, scraping and
abrasion. The ring and cutterhead barkers use no water. Drum
and bag barkers employ the use of water sprays to reduce dust,
promote thawing of wood in cold climates, or to reduce the bond
between bark and wood. Wastewaters high in BOD are generated
from the wet barking processes . The BOD level present in barking
wastewaters is ri^nendpnt on th° type or species o^ tree - Keing
barked and th£ degree of recycling being practiced.
Veneer and Plywood (B,C) - Plywood is an assembly of layers of
wood(veneer) joined together by means of an adhesive. Hard-
wood plywood is generally used for decorative purposes and has
the "face ply" of wood from deciduous or broad leaf trees.
Softwood plywood is generally used for construction and struc-
tural purposes, and the veneers are of wood from coniferous or
needle bearing trees. The principal unit process in the manu-
facturing of veneers is the cutting of the veneer. The partic-
ular cutting method used determines the appearance of a plywood
panel.
Prior to cutting the veneer, the logs may be conditioned by
steam treatment or by immersion in a hot water vat. Wastewaters
are high in BOD, COD and total solids.
Freshly cut veneers must be dried in order to avoid attack by
molds and fungi and to render them compatible with the gluing
process. Surfaces of veneer dryers accumulate wood particles
and pitch, which may be removed by scraping followed by flushing
with water or by blowing with air. Generally pitch must be
dissolved by detergent washing and rinsing. The nature and
quantity of this wastewater varies according to the amount of
water used, the amount of scraping prior to application of water,
condition and operation of the dryer, and the species of wood
being dried. Most driers are equipped with deluge systems to
extinguish fires that start inside the drier. Fire deluge water
can add significantly to the wastewater problems in some cases.
A number of adhesives can be used in the gluing operations. The
glue is mixed and then applied by means of a spreader. The glue
system must be cleaned regularly to avoid build-up of dried
8-25-3
-------
glue. Wastewaters are high in BOD, COD and total solids.
After gluing, the layers of veneer are subjected to pressure
to insure proper alignment and intimate contact between the
wood layers and the glue. After the pressing operation any
number of finishing operations can take place. These include
redrying, trimming, sanding, sorting, molding, and storing.
Figure 8-25-2 contains a process flow diagram for veneer and
plywood production.
Hardboard (D,E) - Hardboard is manufactured by reducing wood
materials to the fibrous state- and putting them back together
in the form of sheets or boards, in the wet process (E) water
is used as the medium for carrying the fibers and distributing
them in the forming machine; part of the carrying water is
removed and a slight amount of pressing is done. The mats are
then transferred to a press for additional pressing. In the
dry process (D) air serves as the carrying-and distributing
medium. Figure 8-25-2 contains a flow diagram for hardboard
manufacturing. Logs or wood scraps must be either processed
to chips at the hardboard manufacturing plant or off-site. The
wood chips are then pretreated or softened with steam prior to
pulping. The two major pulping processes are the explosion
process and the thermal plus mechanical refining. In the explosion
process wood chips are subjected to high temperature steam in a
"gun", or high pressure vessel, and ejected through a quick open-
ing valve. Upon ejection the softened chips burst into a mass
of wood fibers. The second process, which consists of softening
the fibers with heat and then mechanically pulping the wood
chips is more widely used. The mechanical pulping takes place
in disc refiners or attrition mills. After the addition of
additives to the pulp, the pulp is ready for delivery to the
board former to begin the process of reassembling the fibers
into hardboard.
In the wet process the mat is usually formed on a fourdrinier
type machine similar to those used in paper making. The wood
pulp is diluted and is then passed onto an endless traveling
wire screen. The water is removed by gravity through the screen,
and then further moisture is removed by suction. Additional
water is removed as the sheet passes through rollers. The water
removed in the mat formation is recycled. However, periodic
purging constitutes a waste stream.
In the dry process the fibers are suspended in air rather than
water. The prepared fibers are fed by a volumetric feeder to the
"felting unit" where the fibers are distributed onto a moving
screen at the floor of the felter. Air is sucked through the
screen to aid in the felting. Periodic cleaning of the press
plates constitutes a waste stream.
8-25-4
-------
I IUUIU WAS It
OVERFLOW FROM
LOG PONO
.SOLIDS __
LIQUIDS
STIAM ORItR WASH
CONOCN3ATE AND OILUOt
AIER
EXHAUST
OASES
4ENIIS VENEER I
" i AT^r ~"* nttiEH "
SOLID WASTE IS BURNED IN SOI LIU
CHIPPED FOK REUSE OR SOLD
Or-
IEPARATIONT
LlL .
I>MP*R
-------
When the reassembly of the wood particles is completed the
fibers are welded together into a tough, durable grainless
board on the hardboard press.
After being discharged from the press the hardboard may be oil
tempered by bathing the hardboard in an oil bath to increase
its hardness, strength, and water resistance. It may also
receive a paint finish. The wet process produces significant
quantities of wastewater which are high in BOD, COD and suspended
solids.
Wood Preserving (F,G,H) - The wood preserving process is one in
which round and sawn wood products are injected with chemicals
that provide fungistic and insecticidal properties, or impart
fire resistance. The most common preservatives are creosote,
pentachlorophenol, and various formulations of water soluble
inorganic chemicals. Fire retardents are formulations of salts
including borates, phosphates, and ammonium compounds. Treat-
ment is accomplished by either pressure or non-pressure processes.
The pressure process employs a combination of air, hydrostatic
pressure and vacuum procedures. Non-pressure processes utilize
open tanks and either hot or cold preservatives in which the
wood is immersed.
Some woods are conditioned by either steam (G) or by a process
called Boultonizing (H) in order to render the stock more
penetrable to preservative treatment. Steaming is usually
carried out at 245°F for periods of from 1 to 16 hours in the
same vessel in which the preservative is injected. In the
Boultonizing process wood is heated under vacuum in the vessel
at 180 - 220 F. Wastewaters contain preservative and chemicals
used in the process; leachate from the wood including oils,
phenolic compounds, and carbohydrates. These discharges exert
a high oxygen demand.
Wet Storage (I) - The harvesting of timber is seasonal in most
parts of the United States. Consequently, log storage is often
essential for continuous mill production. In addition, preserva-
tion of the raw material while in storage is necessary to insure
that the quality of the product is not impaired. Storage and
preservation techniques usually involve the use of water. When
logs are stored on land, they must be sprayed with water to
prevent the ends from cracking. Logs may also be stored in log
ponds, river impoundments, or directly in marine or estuarine
waters. Wood products consisting of planer shavings, sawdust,
and bark are stored in piles and sprayed with water to reduce
dust. Runoff from spraying as well as from rain generates
leachate. Wastewaters produced as a result of storage and
preservation are high in total solids, COD and color.
8-25-6
-------
Log Washing (J) - Logs are .sometimes washed by applying water
from fixed nozzles for the purpose of removing foreign material
from the surface of the log before further processing. This
process results in improved fuel quality (if used as a fuel)
or increased saw life. When logs are stored in a body of water
the benefits of log washing are accomplished. Wash waters
contain settleable solids and can be recycled.
Sawmills and Planing Mills (K) - This subcategory includes the
timber products processing operations of sawing, resawing,
edging, trimming, planing, and/or machining.
The term "headrig" is used by the industry to include all the
machinery which is utilized to produce the initial breakdown
of a log into boards. Subsequent sawing operations reduce the
thickness of the lumber and square the edges. The lumber may
be passed through a preservative and sold or it may be air
or kiln dried. Water usage at sawmill operations vary signi-
ficantly. A majority of sawmills use no process water at all.
On the other hand, a sawmill producing power, washing logs, and
practicing wet storage of logs may use over 10 million gallons
of water per day. Wastewater characteristics from the latter
are discussed elsewhere.
Finishing (L) - Finishing operations include drying, dipping,
staining, coating, moisture proofing, machining, -fabricating
and by-product utilization. Machining is the process of shap-
ing wood to a desired form (shakes, shingles, flooring) and
generates no wastewaters. Fabrication involves the production
of crates, windows, mobile dwellings and is accomplished by
mechanical fastening or adhesives. The use of adhesives normally
necessitates a certain amount of wastewater because of cleanup
operations. By-product utilization involves the production
of pressed logs, chair seats, etc. and are insignificant sources
of wastewater. The only source of wastewaters result from the
washing of equipment. Because of the wide variety of finished
products and their methods of application, wastewaters can be
expected to contain a wide variety of constituents.
Particleboard (M) - Particleboard is defined as board products
that are composed mainly of distinct particles of wood (not
reduced to fibers) which are bonded together with an organic
or inorganic binder. Figure 8-25-2 contains a flow diagram for
Particleboard processing.
Wood residues are mechanically reduced, classified by size and
shape, dried, blended with additives, and formed into a uniform
mat on a forming machine. After the formation of a mat it is
pressed, cut and finished. Finishing operations include sanding,
8-25-7
-------
planing and coating. Fires are a frequent occurance in this
operation.
Wastewaters are generated from equipment washups, cooling and
mat sprays, air pollution control equipment, and fire sup-
pression water. Contaminants include resins (urea or phenols),
oils, wax, wood fibers, finishing materials (stains, dyes,
coatings), depending upon the particular materials utilized in
the operation.
Insulation Board (N,0) - Insulation board is a fiberboard
produced from wood in a fibrous state. Those plants that pre-
condition the raw material with steam are included in sub-
category 0, while those that do not subject the wood material
to steam pressure are included in subcategory N.
Seventy percent of the raw material for this industry is in the
form of wood chips, which are washed in order to remove grit,
dirt, sand and metal. Wash water is usually recycled. Wood
then enters the refining machine where it is fiberized and
diluted in preparation for mat formation. Drying and finishing
operations are similar to particleboard (L) operations. Large
quantities of wastewater are present containing leachable
materials from the wood and additives added during the process.
Discharges are characterized by high quantities of BOD, COD,
suspended solids, and dissolved solids. Figure 8-25-2 contains
a flow diagram for Insulationboard processing.
Wood Furniture and Fixture Production(P,Q,R,S) - The principal
raw materials used in furniture manufacturing are lumber,
veneer, plywood, hardboard and particleboard. The materials
are cut, planed, sanded, bent by steam application, and assembled
with glue and/or metal fasteners. The furniture is then finished
in a variety of operations including bleaching, staining, filling,
sealing and topcoating.
The various finishing materials may be applied by brush or roller,
but most often they are sprayed onto the wood surfaces. Spray-
ing operations require the use of spray booths to collect and
contain the overspray and thus provide fire and health protection.
The air drawn through the booth is filtered by either a dry or
a water wash method. The dry method consists of filtering the
air through a filter consisting of paper or fiberglass. In the
water wash method, water is brought into contact with the exiting
air and removes the impurities. This water stream is the source
of wastewaters.
In the larger plants laundry facilities for rag cleaning are
common and represent a major wastewater source.
8-25-8
-------
4. Wastewater Characterization
Cleaning operations are the major source of wastewater in
this industry, generating intermittent flows. Table 8-25-1
contains raw wastewater characteristics for the various sub-
categories . Some other pollutant parameters that may be
present in process waters of various segments of the timber
products processing industry are: pentachlorophenol, (Uoxins,
dinitrophenol, acenapthene, 2;4 - dichlorophenol, benzene,
chromium, toluene, ammonia, fluoride, copper, zinc and arsenic.
5. Control and Treatment Technology
In-Plant Control - Wastewater reduction measures in this industry
consist primarily of clarifying and recycling techniques. Dry
cleaning operations can reduce wastewater flows. In the veneer
and plywood industries, the dryers can be scraped prior to
washing, thus reducing discharges.
Treatment Technology - Since most timber products are biodegrad-
able, biological treatment is practicable. Table 8-25-2 contains
removal efficiencies for different treatment schemes practiced
by this industry.
8-25-9
-------
TABLE 8-25-1
WASTE CHARACTERIZATION - TIMBER PRODUCTS INDUSTRY
Waste
Parameter
Flow GPD
Flow Type
BOD (mg/l>
TSS (mg/1)
COD (mg/1)
PH
Color
Phosphates
as P(mg/l)
Phenols(jng/]
Oil and
Grease Gng/1
SUBCATEGORIES
Log
Barking-A
56-250
500-
3000
Under 50
Units
)
Veneer and Plywood - B,C
Log Con-
ditioning
C
300-
5,000*
70-
3000
1500-
15,000*
3.8*-7
1-6
0-1
Veneer
Dryer
Washwater
15,000
B
60-
900*
80-
5,000
60-
7,000*
0-11
0-5
Washing of
Glue Tanks
and Tanks
4,000
B
400-
10,000*
6,000-
15,000
9,000-
33,000*
6-40
24-100
Hard Board
Dry Process
D
Low
Flows
Hard Board
Wet Process
E
200M-4MM
C
700-
4000*
220-
1700
2,600-
12,000*
4-5
0.3-3
0.7-1.0
Wood
Preserving
F,G,H
20M
C
150
200-
5000
2M-30M*
4-6
50-
1,000
50-600*
Wet Storage
(on land only)
I
160M-2MM
C
3-200
4-125
20-200
30-300
0.5-7
5-170
Log
Washing
J
384M
C
75-200
100-260
70-300
0.1-3
80
00
U1
M
O
NOTE: M = 1,000
MM = 1,000,000
* See Appendix 5 for parameters which may be inhibitory to biological systems
B - Batch
C - Continuous
-------
TABLE 8-25-1 (Continued)
Haste
Parameter
Flow GPD
Flow Type
BOD (mg/l)
TSs(mg/l)
COD( mg/l)
EH
Color
Phosphates
as P(mg/l)
Phenols (mg/l)
Oil and
Grease (mg/l)
Sawmill s-K
Fabrication
only
530-124M
C
700-16,000*
700-5000
4,000-17000*
5-11*
1-20
0-300
SUBCATEGORIES
Finishing
L
20-400
B
400-250M
8M-245M
100-6500
100-5000
Particleboard
M
50-86M
C & B
6-250
30-300
100-300
6-12*
15-400
0-1
0-20
1-50
Insulation
Board
N,O
416M-3MM
C & B
300-3000*
1500-2000
2000-7500*
FURNITURE MANUFACTURE (1)
Spray
Booths H
1500-5M(per wk
B
130-16,000*
100-40,000
3,000-100,000*
7-13*
40-500
Glue
Washwater Q
5-1600 (per wk)
B
100-300
300-9000
11,000-40,000*
5-9
0-400
Laundry
Wastes R
200-5M(per wk)
B
8,000*
18,000
35,000*
12*
500
00
Ul
Mote: M = 1,000
MM = 1,000,000
B - Batch
C - Continuous
* See Appendix 5 for parameters which may be inhibitory to biological systems
(l) where spray booths and laundries are both utilized, the wastewater characteristics are
a composite of the individual values shown.
-------
TABLE 8-25-2
TIMBER MANUFACTURING INDUSTRY
WASTE WATER TREATMENT PRACTICES
REMOVAL (Percent)
POLLUTANT S METHOD
SUBCATEGORIES
F G H
M N 0 Q R
N)
Ul
I
I-1
BOD
Primary Clarification with
Biological Treatment
Containment with Recycle
TSS
85-95
70-97 80-
90
90
78-94
100
Primary Clarification with
Biological Treatment
Containment with Recycle
0-10
0-99
100
COD
Primary Clarification with
Biological Treatment
60
80
50
Recycle, Equalization, Sedi-
mentation
Containment with Recycle
20
100
-------
PULP, PAPER AND
PAPERBOARD
1. General Industry Description
Paper is made from raw materials including wood, cotton, linen
rags, and straw, which contain adequate amounts of cellulose
fiber, the basic component. The cellulose is separated from
other constituents of the fiber source and fiberized by the
pulping process. Today, wood accounts for over 98 percent of
the virgin fiber used in papermaking.
Paper is made by depositing, from a dilute water suspension of
pulp, a layer of fiber on a fine screen which permits the water
to drain through but which retains the fiber layer. This layer
is then removed from the wire, pressed and dried.
Establishments engaged in this industry are covered by Standard
Industrial classifications (SIC) 261, 262, 263. 264 and 265.
Wastewaters from this industry contain suspended solids, BOD, COD
color, mercury, zinc and PCB's.
2. Industrial Categorization
The unbleached kraft and semichemical pulp segment of this
industry has been divided into the following subcategories:
Subcategory Designation
Unbleached Kraft A
Sodium Base Neutral Sulfite Semi-Chemical B
Ammonia Base Neutral Sulfite Semi-Chemical C
Unbleached Kraft Neutral Sulfite Semi-
Chemical (Cross Recovery) D
Paperboard from Waste Paper E
"Neutral Sulfite Semi-Chemical shall be referred to as "NSSC"
in this description.
8-26-1
-------
The remaining segment of this industry has been tentatively
divided into the following subcategories:
1. Groundwood
2. Sulfite
3. Dissolving sulfite
4. Bleached kraft
5. Soda
6. Deinked
7- Non-integrated fine paper
8. Non-integrated tissue paper
9. Non-integrated coarse paper
3. Process Description
Wood Preparation
Wood is received at the mills in various forms and converted to
chips for pulping. If the wood is received with the bark on it,
the log is washed and the bark is removed by drum, pocket, or
hydraulic barkers. Large quantities of wastewaters containing
suspended solids and BOD are generated. Barked logs can be
chipped directly producing little or no effluent.
Pulping
There are several methods used for pulping wood. In some, the
chips are cooked with chemicals under controlled conditions of
temperature, pressure, time and pulping liquor composition. The
various processes utilize different chemicals or combinations of
them. Wood can also be reduced to a fibrous state by mechanical
means or a combination of chemical and mechanical action. The
repulping of waste paper is a hydraulic and mechanical process.
The various pulping methods will be discussed in detail below.
Paper Making
Paper is manufactured in two relatively discreet operations: the
dry end and the wet end. Wood pulp enters the paper machine at
the wet end where it is diluted to a consistency of 0.25-0.5%.
8-26-2
-------
The pulp is then deposited on a cylinder or wire and the excess
machine white water passes through the machine generating a
wastewater. The sheet then passes to the forming and pressing
section of the machine where more water is removed. It finally
passes to the dry end of the machine where the paper is dried.
Figure 8-26-1 is a flow diagram of the paper making process.
Unbleached Kraft (A)
Unbleached kraft is the production of pulp without bleaching by
a "full cook" process, utilizing a highly alkaline sodium
hydroxide and sodium sulfide cooking liquor. This pulp is used
principally to manufacture linerboard, the smooth facing of
corrugated boxes, grocery sacks and wrapping paper.
Wood chips are fed to a digester, where the chips are cooked to
dissolve the lignin and separate the cellulose fibers. The
unbleached kraft is called a full-cook process since the fiberizing
is completed in the cooking process alone. The pulp, along with
the spent cooking liquor is then sent to drum washers where the
pulp and the liquor are separated. The pulp is formed into paper.
The "weak black liquor" from the wash process, containing solids,
inorganic cooking chemicals and organic wood constituents is
concentrated to a "strong black liquor". The "strong black liquor"
is burned and the heat is recovered. The molten smelt on the
furnace floor is dissolved in water to form "green liquor",
which is clarified and causticized with lime. After causticizing,
the combined sodium sulfide-sodium hydroxide solution is known as
"white liquor", and recycled to the pulping process. This
operation generates wastewaters high in COD, BOD and suspended
solids.
Another source of wastewater is condensate streams. These streams
are lew in BOD and TSS, but may contain methanol, ethanol, and
acetone. This wastewater is recycled back into the pulp wash-
water operation in some plants. Figure 8-26-2 is a flow diagram
for this process.
Sodium Base Neutral Sulfite Semi-Chemical (B)
This production of pulp without bleaching utilizes a neutral
sulfite cooking liquor having a sodium base. Mechanical fiberizing
follows the cooking stage. The principal product made from this
pulp is the corrugating medium or inner layer in the corrugated
box "sandwich". In this process, the wood chips are cooked in
either batch or continuous digesters. NSSC refers to the cooking
8-26-3
-------
OVERFLOW
FILTERED
WHITE WATER
TANK
SAVE-ALL
r
j_
RICH WHITE
WATER TANK
COUCH PIT
WIRE PIT
PULP
CHEST
1
REFINERS
1 '
MACHINE
CHEST
'
r
MACHINE
SCREENS
FOURDRINIER
SECTION
PROCESS
WATER
PRESS
SECTION
DRIER
SECTION
LEGEND
PRODUCT and RAW MAT'L
PROCESS WATER
REFUSE WATER
EFFLUENT
Figure 8-26-1
Paper Making
Pulp, Paper and Paperboard
8-26-4
-------
L
CHEM. a L
PROCESS
BACK WA
EFFLUENT
STEAM a
REJECTS
BY-PRODI
EGEND
WATER
TER
5ASES '*
JCTS
1
BLACK LIQUOR
SEAL BOX "
WOOD CHIPS
DIGESTER
BLOW TANK
FIBERIZER
KNOTTERS
TURPS
rJEFFLUENT
1 i
i
TURP
RECOVERY
t 1
1
HOT *ATER
RECOVERY
j WATER j_
PULP
OFF
GASES
OFF
GASES .
t
U»-»»REJECTS I
WASHERS
1 ' '
1
EVAPS ^ .
i
TALLOIL
PROCESS |
WATER
DREGS ----
B L 0.
i
.. ("EFFLUENT
T ;
AIR i
RECOVERY
FURNACE
i
1
1
t
DISSOLVING
TANK
4 1
T 1
DREGS
WASHER
? J " " " ~ -"-"" -J " - «- ' --- j
1
» MUD » _
WASHER
WHITE LIQUOR
CLARIFIER
1 1 I '
r »OFF GASES 1 J
1 |
LIME KILN
UME
PRECIPITATOR
1
:
CONTACT
EVAP
* !
V
MIX TANK
CHEMICAL
MAKE-UP
1
*
GREEN LIQUOR
CLARIFIER
CAUSTIOZER
4
1
1
SLAKER
H
i
*
GRITS
Figure 8-26-2
Pulp, Paper and Paperboard
Kraft Pulping (A)
8-26-5
-------
liquor used in the digester, which may be in the sodium (B) or
ammonium (C) (discussion follows) form. The softened chips from
the digester are then separated from the cooking liquor, and
sent to a disk mill for fiberizing. The pulp is then washed and
is ready for paper making. The final effluent from this process
is low in volume and high in strength due to the high degree of
recycle employed. Wastewaters contain BOD, COD, TSS and color.
The process is shown in Figure 8-26-3.
Ammonia Base Neutral Sulfite Semi-Chemical (C)
This production of pulp without bleaching uses a neutral sulfite
cooking liquor having an ammonia base. Mechanical fiberizing
follows the cooking stage, and the pulp is used to manufacture
essentially the same products as is sodium base NSSC. Wastes
from this process are similar to sodium base NSSC, except that
nitrogen is also present.
Unbleached Kraft - NSSC (Cross Recovery) (D)
In this process, wood chips are combined with the sodium base
NSSC spent liquor (B) in the unbleached kraft (A) process to
produce a pulp. The products include grocery sacks, corrugated
and wrapping paper. Wastes are similar to those generated
from the unbleached kraft pulping plant (A).
Paperboard from Waste Paper (E)
This subcategory includes the production of paperboard products
from waste paper without bleaching, de-inking or wood pulping
operations. Eighty percent of the fibrous materials are derived
from waste papers including corrugated boxes, box board, and
newspapers. Mills that produce paperboard products principally
or exclusively from virgin fiber are not included in this sub-
catQgory. Figure 8-26-4 is a flow diagram for this process.
In this process waste paper is diluted to 4-6% with water, and
is then fed to a pulper along with steam. The pulper consists
of a vat with rotating impeller blades that shred, rip and
finally defiber the waste paper. The pulper can either be batch
or continuous in operation. The fibers are separated from the
solution, cleaned, and then ready for the paper machines.
The major source of wastewater is in the pulp separation and
cleaning operations, and contain components high in BOD, COD
and TSS.
8-26-6
-------
CHIP
STORAGE
TO ATMOSPHERE
DIGESTOR
STACK
GASES
SOt- COt
*
I
.J
BLOW
TANK
REFINERS
SEAL
PIT
WASHER
I*-
EVAPORATOR
~1
SHREDDER
LIQUOR
RECOVERY OR
BURNING
PRODUCT
FLOOR DRAINS
WASHOUTS
OVERFLOWS
PRODUCT 8 RAW MATL.
CHEM. 8 LIQUORS
PROCESS WATER
BACK WATER
STEAM S GASES
EFFLUENT
COOKING
LIQUOR
ABSORBER
SULFUR
DIOXIDE
SODIUM
CARBONATE
STOCK
PREP.
I
WHITE
WATER TANK
rr
1
EFFLUENT
PAPER MACH.
SAVE - ALL
PROCESS
WATER
EVAP. COND.
COOLING H
Figure 8-26-3
Pulp, Paper and Paperboard
Neutral Sulfite Semi-Chemical (NSSC)(B)
8-26-7
-------
LINER
PULPER
CLEANERS
PROCESS
WATER
THICKENER
DUMP
CHEST
DUMP
CHEST
MACHINE
CHEST
MACHINE
CHEST
MIXING BOX
MACHINE
SCREENS
MACHINE
SCREENS
FORMING
SECTION
PRESS
SECTION
DRIER
SECTION
LEGEND
PROD. 8 RAWMAT'L
CHEMICALS
PROCESS WATER
BACK WATER
STEAM
REJECTS
EFFLUENT
MACHINE
PIT
EFFLUENT
Figure 8-26-4
Pulp, Paper and Paperboard
Waste Paperboard Mill (E)
8-26-8
-------
Groundwood
The energy used in producing conventional groundwood pulp-
stone or refiner is mechanical. Modified groundwood processes
such as cold soda (chemi-mechanical) and chemi-groundwood
methods employ a mild chemical treatment ahead of mechanical
fiberizing. The latter processes are considered mechanical
pulping because chemical pretreatment is much milder and the
mechanical action more drastic than is the case in semi-
chemical pulping. In thermo-mechanical pulping, an off-shoot
of refiner groundwood, the pretreatment is accomplished with
heat.
In the basic process, pulp is made by grinding logs, or short
lengths of logs called billets, on a grindstone; pulp produced
by passing wood chips through a disc refiner is termed refiner
groundwood. In the chemi-groundwood process, the billets are
first soaked or sprayed with a dilute solution of sodium sul-
fite before grinding; in cold soda (chemi-mechanical) pulping,
chips are steeped in a caustic solution and refined. Such pre-
treatment softens the wood so that less power is required for
grinding. In thermo-mechanical pulping, chips are first softened
with heat and then refined under pressure.
Bleaching agents such as hydrosulfites and peroxides may be
used in conjunction with mechanical pulping.
This pulp is used principally to manufacture newsprint, or
other printing papers, molded fiber products, and "throw away"
products (toweling, paper plates, tissues).
Wastewaters primarily contain BOD and suspended solids.
Chemical Pulping of Wood
Sulfite, Dissolving Sulfite, Bleached Kraft, Soda, Deinked
As the term implies, the energy utilized in chemical pulping to
separate cellulose fibers from other wood components derives
from chemical application. Wood is cooked in batch or continuous
digesters, large pressure vessels, with solutions of various
chemicals to the point at which non-cellulosic constitutents
are dissolved and the fibers can be liberated by blowing the
digester, or by jets of dilution water in the blow pit. Other
than a simple "opener" device used in conjunction with the
blowing of some high lignin content sulfite pulps, no subsequent
mechanical devices are necessary.
8-26-9
-------
Thus, chemical pulping methods are described as "full cook"
processes. This differentiates them from the mechanical opera-
tions described above and semi-chemical pulping, which employ
both chemical pretreatment and mechanical energy in varying
relative degrees of strength.
Sulfite means the production of pulp, usually bleached, by a
"full cook" process using an acidic cooking liquor of bisulfites
of calcium, magnesium, ammonia, or sodium containing an excess
of free sulphur dioxide. This pulp is used to manufacture a
variety of paper products such as printing papers.
Dissolving Sulfite - Preparation of this pulp is similar to
that discussed above. However, the wood is cooked at a higher
than standard temperature. Cooking is continued until most
of the lignin and part of the cellulose is dissolved. This
pulp is used principally for the manufacture of rayon and other
products requiring the virtual absence of lignin and a very
high alpha-cellulose content.
Bleached Kraft means the production of bleached pulp by a "full
co9k" process utilizing a highly alkaline sodium hydroxide and
sodium sulfide cooking liquor. This pulp is used to make a wide
variety of papers and paperboards such as tissue, foodboard,
and printing papers.
Also included in this subcategory is the production of highly
bleached and purified kraft dissolving pulp utilizing a "pre-
cook" process. Kraft dissolving pulp is used principally for
the manufacture of rayon and other products requiring the virtual
absence of lignin and a very high alpha-cellulose content.
Soda means the production of bleached pulp by a "full cook"
process utilizing a highly alkaline sodium hydroxide cooking
liquor. This pulp is used principally to manufacture a wide
variety of papers such as printing and writing papers.
Deinked means the production of pulp usually brightened or
bleached from recycled waste papers in which an alkaline treat-
ment is utilized to remove contaminants such as ink and coating
pigments. The pulp is used, frequently in combination with
chemical pulp, to manufacture a wide variety of papers such as
printing, tissue, and newsprint.
8-26-10
-------
Non-Integrated Processes (Fine, Tissue and Coarse Papers)
The term "Non-Integrated" means the manufacture of papers from
wood or deinked pulp which has been prepared at another site.
Only paper making occurs at the plant, and the paper making
process has been described earlier.
4. Wastewater Characterization
Tables 8-26-1 and 8-26-2 contain wastewater characteristics for
the industry.
Integrated pulp and paper mills generally operate continuously
throughout the year except for the shutdowns for preventive
maintenance and equipment repair and replacement. Modern
practice is to employ continuous pulping processes; however,
many mills are still using batch pulping processes which result
in continuous discharges of wastewater with frequent surges. In
addition, some older mills (generally relatively small, less than
100 tons/day)operate only 3 to 5 days per week.
The overall wastewater characteristics from wood pulping processes
may vary seasonally because of the changes in characteristics of
wood and other variations. The volume and characteristics of
the process wastewater depend upon the degree of water reuse,
chemical recovery systems, and the type and quality of paper
involved.
The wastewaters generated from the paper and allied products
industry contain BOD, COD, suspended solids, dissolved solids,
color, acidity or alkalinity, and heat.
5. Control and Treatment Technology
Jn-Plant Control
Recyling, recovery and reuse of chemicals and fiber as well
as good housekeeping can significantly reduce discharges.
Substitution of dry barking for wet barking eliminates the
waste flow from this process.
Normally the pulp is diluted to about 1% consistency to promote
effective screening for the removal of knots and shives. The
8-26-11
-------
8-26-1
PULP AHD PAPER IHDUSTRY
RAW WASTEWATER CHARACTERIZATION
WASTE PARAMETER
SUBCATEGORIES
00
1
10
01
1
»-
K>
Flow Type
BOD (Mg/l)
TSS (Mg/l)
Color (Mg/l)
Heavy Metals
Oil & Grease
Unbleached
Kraft-A
C
200-500
200-500
Present
Present
Present
Sodium
Base
NSSC-B
C
1500-5000*
50-600
Present
Present
Present
Ammonia
Base
NSSC-C
C
100-600
200-1000
Present
Present
Present
Unbleached
Kraft
NSSC-D
C
1«X)-750*
150-750
Present
Present
Present
Paper Board
from Waste
Paper-E
C
60-100
100-5000
Present
Present
Groundwood
C
300-3000*
300-5000
Present
Present
Sulfite
C
750*-2000*
150 -koo
Present
Present
Present
Dissolving
Sulfite
C
300-900*
ko-hoo
Present
Present
Present
Bleached
Kraft
C
150-300
200-350
Present
Present
Present
Soda
C
200-600
200-800
Present
Present
Present
Deinked
C
300-500
1000-2500
Present
Present
Present
Non-
Integrated
Plants
C
100-300
300-600
Present
Present
Present
Note: *See Appendix 5 for parameters which may be inhibitory to biological systems
C - Continuous
-------
TABLE 8-26-2
PULP AMD PAPER INDUSTRY
RAW WASTEWATER CHARACTERIZATION
PRODUCTION BASED DATA
WASTE PARAMETER
SUBCATEGORIES
Sodium
Unbleached Base
Kraft-A NSSC-B
00
I
at
u>
Flow (kl/kkg)1
Flow Type
2
BOD (kg/kkg)
2
TSS (kg/kkg)
Note:
1*0-100
C
10-30
10-1*0
20-100
C
10-50
1*-30
Ammonia Unbleached
Base Kraft
NSSC-C NSSC-D
20-100 1(0-80
C C
10-60 15-30
-20 12-30
Paper Board
from Waste
Paper-E
5-50
C
1(-20
3-80
Groundwood
8-17
C
5-50
5-80
Dissolving
Sulfite Sulfite
60-200 230-350
C C
150 100-200
25 10-100
Bleached
Kraft
1*0-110
C
12-50
20-30
Soda
80-125
C
20-50
20-30
Non-
Integrated
Deinked Plants
55-100
C
20-25
100-1*00
80
C
5-20
20-50
kl/kkg - Kiloliters/1000 kg product produced
2
kg/kkg - Kilograms/1000 kg product produced
C - Continuous
-------
pulp is then rethickened on a decker for storage purposes. This
operation accounts for about one third of the total BOD from a
mill. If, after cooking, the pulp is passed through a fibrilizer
which fractionates the knots remaining in the pulp, followed by
a specially designed hot stock screen for removing the shives,
the dilution step is eliminated. This practice reduces the
amount of BOD discharged. Recycle of condensate streams instead
of using new makeup water in plant operations reduces the waste^
water flow.
A rule of thumb sometimes used in this industry is that one third
of the BOD and TSS in the raw waste is due to spills, overflows,
and wash-ups which occur when the production process is not in
equilibrium. These losses occur due to a variety of factors
including breakdown of equipment, routine maintenance, planned
shutdowns and startups, power failures, and grade changes.
These can be avoided by the use of the following techniques:
1) Evaporators should be periodically "boiled out" to remove
scale and other substances, and the flushed material stored and
returned to the mill processes.
2) Storage facilities can be used to store overflows from opera-
tions during upset conditions, and then returned to the process.
3) Continuous monitoring can be used to give immediate warning
to plant upsets.
Many mills use a save-all to recover fibrous material escaping
from the paper machine. This reduces the waste load.
Treatment Technology
Suspended solids can be reduced by mechanical clarifiers,
flotation units or sedimentation lagoons.
BOD reduction is generally accomplished by biological means,
including oxidation basins, aerated stabilization basins, and
the activated sludge process.
Color removal is accomplished by lime treatment with clarifi-
cation, coagulation with alum and ferric chloride and activated
carbon.
Refer to Table 8-26-3 for removal efficiencies for the various
processes.
8-26-14
-------
TABLE 8-26-3
PULP AND PAPER INDUSTRY
WASTEPAPER TREATMENT PRACTICES
Pollutant and
Method
Removal Efficiencies
Percent
TSS
Mechanical Clarifiers
Dissolved Air Flotation
Up to 95%
Up to 98%
BOD
Biological Treatment
85 - 99 %
COLOR
Lime Treatment
Coagulation with
Aluminum and Ferric Chloride
Activated Carbon
74 - 91
80 - 90
70
8-26-15
-------
BUILDER'S PAPER AND
ROOFING FELT
1. General Industry Description
This industry manufactures heavy papers for the construction
industry from varying combinations of wood, waste paper and/
or rags. Establishments engaged in this industry are covered
by Standard Industrial Classification (SIC) 2661.
2. Industrial Categorization
Since both Builder's Paper and Roofing Felt are similarly pro-
cessed, they constitute one discrete category.
3. Process Description
Building papers are generally characterized as saturating
papers, flooring paper, and deadening paper which are used
in the construction and automotive industries. They differ
from unsaturated roofing felts only in thickness and possible
chemical additives added to the process in order to achieve
a specific property. The function of dry roofing felt is to
provide a strong, highly absorbent material as a backing for
the coatings which provide the characteristics desired in the
finished product, i.e. water repellancy, weather & heat resistance,
and strength.
A flow diagram for the industry is shown in Figure 8-27-1.
The manufacture of building paper involves three processes:
1. Stock preparation area
2. Wet end of machine
3. Dry end of machine
(1) Stock Preparation Area
Raw materials including waste paper, defibrinated wood* wood
flour, pulp mill rejects, rags, wood chips, and sawdust are pre-
pared for use. Wood chips are pulped,occasionally preceded
by a steaming process. Rags & waste paper are cut, shredded,
pulped and mixed with water. The various stock components
are blended, and stored in a machine stock chest.
(2) Wet End Area
The stock is pumped from the stock chest through a cylinder wire
where fibers are retained and a sheet is formed. The water passes
through the wire and is recycled.
8-27-1
-------
WOOD CHIPS
DEFIBRINATOP.
STOCK
CHEST
REFINER
CHEST
WHITE
HATER
CHFST
SAVE-ALL
BUILDING PAPER
or
UNSAT. FF.LTS
EFFLUENT
SCREEN
FORMING
MACHINE
ORIER
SATURATING &
COATING
WASTE
PAPFR
PULPF.R
STOCK
CHFST
JORDAN
CHEST
REJECTS
PROCESS
WATER
ROOFING FELTS)
SHINGLES
LEGEND
PRODUCT8 RAW MAT'L -
PROCESS WATER -
BACK WATER
STEAM
REJECTS
EFFLUENT-
FIGURE '8-27-1
BUILDING PAPER AND ROOFING
FELT PROCESS DIAGRAM
8-27-2
-------
(3) Dry End Area
The sheet passes through the dryer section. This building
paper may be the final product or it may be subject to
additional processing to produce roofing felt.
Saturating and Coating - The paper may be saturated with asphalt
and coated with talc. Cooling water is supplied after each
saturation generating a wastewater. The saturated felt may
be subjected to a coating of granular stone and/or mica. These
particles fall to the floor and are washed to the sewer. This
wastewater represents a principal source of inert suspended
solids.
4. Wastewater Characterization
Table 8-27-1 shows the raw waste loadings for the industry.
5. Control and Treatment Technology
In-Plant Control - Large quantities of water are necessary to
form a sheet of paper. In recent years very extensive recycling
has been achieved by the industry. One mill reports a completely
closed process water system with no discharge to the environment
using the activated sludge process.
Most mills employ a save-all or filtration system to recover
fibrous and other suspended solids. High pressure low volume
showers for cleaning purposes reduces water use. Cooling towers
are utilized to control thermal discharges and make cooling
water suitable for reuse.
Treatment Technology - The dissolved organic components of
cellulosic products as well as adhesives, sizing materials
and resinates present in the waste load are amenable to
biological treatment.
8-27-3
-------
TABLE 8-27-1
RAW WASTEWATER CHARACTERISTICS
BUILDERS PAPER AND ROOFING FELT
Parameter Concentration
Flow Range
BOD
TSS
BOD
TSS
(1/1000 kg)
(kg/1000 kg)1
(kg/1000 kg)1
(mg/1)
(mg/1)
4,200/54,000
7/13
4/42
130-3,000*
75-10,000
Note:
(1)
kg/1000 kg and 1/1000 kg is based on product
produced (lower limit/upper limit)
* See Appendix 5 for parameters which may be
inhibitory to biological systems.
8-27-4
-------
MEAT PRODUCTS
1. General Industry Description
Meat packing plants carry out slaughtering and processing of cattle,
calves, hogs, and sheep fior the preparation of meat products and
by-products. Meat processing plants purchase animal carcasses, meat
parts, and other materials and manufacture sausages, cookdd meats,
cured meats, smoked meats, canned meats, frozen and fresh meat cuts,
natural sausage casings, and other specialties.
Establishments engaged in the meat slaughtering processing industry
are included in Standard Industrial Classifications (SIC) 2011,2013,2032,
2077.
2. Industrial Categorization Designation
Simple Slaughterhouses A
Complex Slaughterhouses B
Low-Processing Packinghouses C
High-Processing Packinghouses D
Small Processor E
Meat Cutter F
Sausage and Luncheon Meats Processor G
Ham Processor H
Meat Canner I
Renderer j
3. Process Description
Figure 8-28-1 is a process flow diagram for the meat industry that
shows the various processes described below.
Simple Slaughterhouse (A) A slaugherhouse is a plant that slaughters
animals and has as its main product fresh meat as whole, half or
quarter carcasses or smaller meat cuts. A slaughterhouse includes
the following operations:
Livestock Pens - Contain the animals while waiting their turn for
slaughter. Wastewater results from watering troughs, washdowns,
urine and runoff if the pen is not covered.
Slaughtering - The slaughtering of animals includes the killing and
hide removal in the case of cattle, calves and sheep; and scalding
and dehairing for hogs; eviscerating; washing of the carcasses and
cooling.
The blood, hides, hair and viscera are subject to further processing.
A slaughterhouse which is subcategorized as "simple" may send these
by-products out for further processing or may engage in only one or
two of these by-product processing operations:
8-28-1
-------
Meat Parts
00
I
to
00
I
to
Tripe
Chitterlings
Sausage casings
Surgical sutures
Animal feed
FIGURE 8-28-1
MEAT INDUSTRY
-------
Bv-Product Operations
(1) Blood Processing - The blood may be heated to coagulate the
albumin; then the albumin and fibrin are separated for further pro-
cessing into pharmaceutical preparations. The blood water may be
evaporated for animal feed or it may be discharged. In most cases,
the whole blood is sent directly to conventional blood dryers and
used for animal feed.
(2) Viscera Handling - The contents of the paunches, 50 to 70
pounds of partially digested feed^may be washed out with water and
passed over a screen. The separated solids go to solid waste hand-
ling. The liquor is generally sewered. The paunch contents are
sometimes dumped on the screen without the use of water and are
dried and removed. In some plants the entire paunch contents are
sewered. The paunch is washed thoroughly if it is to be used for
edible products.
Intestines may be sent directly to rendering or they may be hashe'd
and washed and then sent to rendering. Paunches, stomachs and in-
testines can be marketed as tripe, chitterlings, sausage casings,
surgical sutures, mink or pet food. Viscera handling results in
stomach.contents, intestines, and considerable grease being dis-
charged in the wastewater.
(3) Hide Processing - Hides may be processed wet or dry. Wet pro-
cessing involves hide demanuring, washing and defleshing, followed
by a brine cure in a brine vat or raceway. In dry curing, the
washed defleshed hides are packed with salt and stacked in the curing
room. Hide processing leads to significant loads of blood, tissue,
dirt and salt in the wastewater.
(4) Cutting - In the cutting area carcasses are cut for marketing
or for further processing. The trimmings may be used for sausage
and canning, or for rendering of fats and tallows. Much of the
meat, bone, dust, fat, tissues, and blood is discharged during clean-
up.
(5) Rendering separates fats and water from tissue. Inedible render-
ing utilizes bones, offal, condemned amimals and is used in animal
feed. The materials are passed through a grinder and rendered by
one of three methods: wet, dry, or low temperature.
8-28-3
-------
In the wet rendering process the ground trimmings are pressure
cooked. The fat phase is separated, the solids are screened out,
and the tankwater is evaporated to a thick protein-rich material
known as "stick" which is added to animal feed.
In dry rendering the most widely used process, the material is cooked
until the moisture is driven off. The cooked material is screened
to remove the fat from the solid proteinaceous residue.
In low temperature rendering the finely ground material is heated
to just above the taelting point of the fat. The fat is separated
by centrifugation.
Spills and discharges from washdown further contribute to waste-
water discharges.
Grease recovery operations effectively remove pollutants and recover
valuable by-products.
Complex Slaughterhouse (B) A slaughterhouse that does extensive by-
product processing, usually including at least three of the by-product
operations discussed in (A) is subcategorized as "complex".
Low-Process ing Packinghous e (C) A packinghouse is a plant that both
slaughters and processes fresh meat to cured, smoked, canned, and
other meat products. A packinghouse that is subcategorized as "Low
Processing" is one that processes no more than the total animals
killed at that plant, normally processing less than the total kill.
The processed meat products for this subcategory are limited to:
chopped beef, meat stew, canned meats, bacon, hams, franks, wieners,
bologna, hamburger, luncheon meat loaves, and sausages.
High-Processing Packinghouse (D) A packinghouse which includes all
the processes described in (C) but processes all animals slaughtered
at the site plus additional carcasses from outside sources is sub-
categorized as "High-Processing."
Meat processors (E-I) purchase animal carcasses, meat parts and
other materiaIs in either a fresh or frozen state and manufacture
aaueagea, cooked neata, cured B»ats, smoked meats, canned meats,
frozen and fresh meat cuts, natural sausage casings and other
prepared meats and meat specialties.
8-28-4
-------
The frozen raw materials are handled in one of three ways:
1. Wet thawing
2. Dry thawing
3. Chipping
Frozen materials that are wet thawed are submerged in tanks con-
taining warm water. This process generates a large volume of waste-
water.
The other two thawing methods generate wastewater from clean-ups.
In dry thawing the meat is allowed sufficient time to thaw. Chipping
involves size reduction equipment designed to handle frozen meat.
Small Processor (E) The small processor is one which produces
6,000 Ib. (2730 kg) or less of finished product per day of any type
or combination of finished meat products.
Meat Cutter (F) Meat cuts and portion controlled products are pre-
pared for hotels, restaurants, institutions and fast food outlets.
Sausage and Luncheon Meats (G) These are comminuted meat products
which require substantial size reduction, intensive mixing, and
usually the molding or forming of the finished product.
Ham Processor (H) The production of hams and bacon, involves the
preparation of the raw material for the injection or application of
a pickle solution followed by cooking and smoking. The products are
then cooled, aged if desired, sliced and packaged.
Meat Canner (I) Can filling is a highly mechanized high-speed oper-
ation. This operation results in a substantial quantity of waste-
water from spills and from frequent equipment wash-ups. The pres-
surized cooking of canned meat products does not generate a waste
load.
Renderer (J) The Tenderer as covered in this subcategory consists
of both the offsite or independent renderer and the on-site or
captive renderer. The independent renderer reprocesses discarded
animal materials such as fats, bones, hides, feathers, blood, and
offal into saleable by-products, almost all of which are not suit-
able for human consumption. Also processed are -demo stock",
which are whole animals that die by accident or through natural
causes. A captive renderer is housed on the same premises as the
meat processing plant and conducts its business as an adjunct to the
meat processing operation. Products include edible lard and tallows
made from animal fats, in addition to providing inedible by-products.
8-28-5
-------
4. Wastewater Characteristics
Wastewater characteristics are shown in Table 8-28-1 and 8-28-2.
The meat industry is a year round operation with daily operation
on an intermittent basis. Plants usually shut down daily for
extensive cleanups.
5. control and Treatment Technology
The wasteload discharged from the meat industry can be reduced
to desired levels, including no-discharge of pollutants, by
conscientious wastewater management, in-plant waste controls,
process revisions, and by the use of primary, secondary, and
tertiary wastewater treatment. Figure 8-28-2 is a schematic
of a possible waste reduction program to achieve high removal
of pollutants.
In-Plant control
Livestock holding pens may be covered and dry cleaned with only
periodic washdown. Solid wastes may be disposed of on farm land
as fertilizer. A separate sewer and manure pit may be provided
for liquid wastes. Disposal may be on land or to secondary
treatment systems.
Blood Handling - Blood may be totally contained and collected,
and water use avoided in the blood handling system.
Water from washups can be minimized and drained into the blood
collection system. Bloodwater can be avoided by installing a
blood dryer or it can be rendered, evaporated, or mixed with
paunch and cooked to produce a feed material. Since blood has
a high BOD5 value and can generally be recovered, discharge of
blood directly to POTWs should be avoided.
Paunch Handling - paunch contents need not be washed out. Dump-
ing the contents followed by high pressure but minimal water
rinse minimizes the wasteload from this operation. Vacuuming
the contents can also be considered. Liquids screened from the
paunch material can be collected and evaporated or rendered.
Consideration may be given to transporting the entire unopened
paunch to rendering. In any event, the discharge of paunch
manure to POTW collection systems should be avoided if possible.
Viscera Handling - inedible viscera can be rendered without washing.
Slaughtering - Troughs under the killing floor are very effective
in collecting and containing blood and solids.
Rendering - The water centrifuged from this process can be sold as
50-60% edible stickwater instead of discharging. Tankwater from
wet rendering has a BODc range of from 22,000 - 45,000 mg/1. it
can be evaporated and blended into animal feed.
8-28-6
-------
RAW
TABLE 8-28-1
MEAT PRODUCTS INDUSTRY
WASTEWATER CHARACTERISTICS
Flow Range (GPD)
Average Flow (GPD)
Flow Type
BOD Range (Mg/l)
Average BOD (Mg/l)
TSS (Avg) (us/i)
TSS (Range) (Mg/l)
IDS (Mg/l)
COD (Mg/l)
00
i PH
CO
-j Color
Grease (Mg/l)
Phosphorus (Mg/l)
Kjeldal N(Mg/l)
Ammonia (Mg/l)
Hitrates (Mg/l )
Nitrites (Mg/l)
Chlorides (Mg/l)
Total Coliform Gnillion/100 ml)
Fecal Coliform (million/100 ml)
Temperature ( C )
Note: *See Appendix 5 for parai
Simple
Slaughterhouse
A
7M-2.11*MM
30OM
B
500-11*00*
1100
1050
70-1500
500-2500 *
290-1(600*
6.5-8.5
High
1*00*
9.4
128
7-50
.02-4.5
.02-1*. 5
438
.5-60
.012-1.6
27-38
deters which may be
Complex
Slaughterhouse
B
148M-4.9MM
1.16MM
B
500-1400*
1500
1300
70-1500
500-2500 *
290-4600*
6.5-8.5
High
800*
45
114
7-50
.02-4.5
.02-1*. 5
380
.5-60
.012-1.6
27-38
Low Processing
Packinghouse
C
50M-6.2MM
90CM
B
500-lltOO*
1000
750
70-1500
500-2500 *
290-1*600*
6.5-8.5
High
1*00*
17
68
7-50
.02-1*. 5
.02-4.5
460
»5-6o
.012-J..6
27-38
inhibitory to biological treatment
High Processing
Packinghouse
D
10M-6.6MM
1.16MM
B
500-1400*
1300
850
70-1500
500-2500*
290-1*600*
6.5-8.5
High
700*
30
105
7-50
.02-4.5
.02-1*. 5
121*6*
.5-60
.012-1.6
27-38
systems
Small
Processor
E
3-15M
81*0
B
500-i4oo*
1000
250
70-1500
550
560
6.5-8.5
High
150*
70
200
68
11.8
2.1
1060*
.5-60
.6
27-38
Meat
flutter
F
300-152M
9940
B
50O-ll*00*
875*
1100
70-1500
1*00-1200*
480
6.5-8.5
High
200*
8
5
1
.88
.01*
162
46.5
.44
37-38
Sausage and
Luncheon Meats
G
1000-1. 56MM
120,800
B
500-1400*
275
360
70-1500
1300*
480
6.5-8.5
High
125*
20
25
1.5
1.14
.3
464
.5-60
.012-1.6
27-38
Ham
Processor
H
270-1. 7MM
92,700
B
500-11*00*
525
300
70-1500
3000*
1200*
6.5-8.5
High
225*
28
20
1.5
2.07
.82
758
22
.38
27-38
Meat
Canner
I
27, 600-1. 097MM
240,300
B
500-1400*
1000*
400
70-1500
2000*
2500*
6.5-8.5
High
185*
80
4o
6
.01*
.14
13.5-138
.56
.012
27-38
B - Batch Operation
M - 1000
MM - 1,000,000
-------
Table 8-28-2
MEAT PRODUCTS INDUSTRY
RAW HASTE CHARACTERISTICS BASED ON PRODUCTION
CO
1
CO
1
00
Parameter
Flow Range (1/kkg)
Flow (Average ) ( 1/kkg
BOD Range (kgAkg)2
BOD (Average ) ( kg/kkg
SS Range kg/kkg )
SS (Average ) (kg/kkg)
Simple
Slaughterhouse
A
1334/14641
) 5,328
1.5/14/3
) 6.0
.6/12.9
5.6
Complex
Slaughterhouse
B
3627/12507
7,379
5.4/18.8
10.9
2.8/20.5
9.6
Low Processing
Packinghouse
C
2018/17000
7,842
2.3/18.4
8.1
.6/13.9
5.9
High Processing
Packinghouse
D
5444/20261
12,514
6.2/30.5
16.1
1.7/22.5
10.5
Small
Processor
E
83/25000
.99/1.1
.73/.B6
Meat
Cutter
F
175/3635
.23/1.09
.34/.94
Sausage 6
Luncheon Meats
G
1084/26100
.5/5.4
.12/12
Ham
Processor
H
288/29200
.24/16.2
.15/9.45
Meat
Canner
I
3170/20375
.8/24
.46/11.5
liters/1000 kilograms live weight killed (lower limit/upper limit)
2kg/1000 kilograms live weight killed (lower limit/upper limit)
-------
V.!:tc
oo
I
N>
OO
I
VO
A i 'uO -L'-.PJl.
Secondary
Treatment
\
t
BOD, Sus.
Solids,
Grease
Removal
to 98.5%
BOD5
V
»
End- of
Process
J
Partial
Tertiary
Treat.
)
Removal of
Fine SUB,
Solids, Salt,
Phosphorus,
Ammonia (as
necessary)
to 99.5%
BODr
No
Dinch.-'.rt-o
SoC(.T.i;:iry
Figure S-28-2
Meat Industry Waste Reduction Program
-------
Hide Processing - Overflows from the hide curing vat may be con-
tained and treated separately. Curing vat solutions high in salt
are dumped infrequently - perhaps only annually, but should be
drained gradually over a 24 hour period, to avoid shock load to the
treatment system. The life of the curing solution can be extended
by pumping it over a screen.
Scald Tank - The hog scald tank contains settled solids and waste-
water with a high wasteload. This wastewater can be collected,
treated and reused. Slow drainage of the tank will reduce shock
load on the treatment system.
Pickling and Curing solutions are high in sugar and salt content.
Reuse of these solutions can minimize wastewater loads.
Plant and equipment cleanup consumes a substantial quantity of
water. Dry cleaning and scraping prior to washdown can minimize
waste loads.
Treatment
Equalization tanks reduce fluctuations in waste streams. Static,
vibrating and rotary screens are used to intercept the solids, thus
reducing waste load to the treatment plant. A catch basin equipped
with a skimmer to remove grease and scum, and a scraper to remove
the sludge are commonly used. Dissolved air flotation is the single
most effective device that a meat packing plant can install to
remove fine suspended solids and grease. Improved performance of
the air flotation system is achieved by coagulation of the suspended
matter prior to treatment.
After in-plant primary treatment/ the following biological systems
are commonly used: anaerobic processes, aerobic lagoons, variations
of activated sludge and high rate trickling filters. Tertiary treat-
ment systems can further reduce pollutants.
Table 8-28-3 shows wastewater treatment practices and the per cent
removals obtained in the meat industry.
8-28-10
-------
Table 8-28-3
Meat Industry
Wastewater Treatment Practices
Treatment
System
Use
Effluent Reduction
Dissolved air flotation
(DAF)
DAF with pH control and
flocculants added
Anaerobic + aerobic
lagoons
Anaerobic + aerated 4-
aerobic lagoons
Anaerobic contact
process
Activated sludge
Extended aeration
Anaerobic lagoons +
rotating biological
contactor
Chlorination
Sand filter,
Microstrainer
Electrodialysis
Ion exchange
Ammonia stripping
Carbon adsorption
Chemical precipitation
Reverse osmosis
Spray irrigation
Flood irrigation
Ponding and evaporation
Primary treatment
or by-product
recovery
Primary treatment
or by-product
recovery
Secondary treatment
Secondary treatment
Secondary treatment
Secondary treatment
Secondary treatment
Secondary treatment
Finish and
disinfection
Tertiary treatment &
Secondary treatment
Tertiary treatment
Tertiary treatment
Tertiary treatment
Tertiary treatment
Tertiary treatment
Tertiary treatment
Tertiary treatment
No discharge
No discharge
No discharge
Grease, 60% removal, to
100 to 200 mg/1
BOD5, 30% removal
SS, 30% removal
Grease, 95-99% removal,
BOD5, 90% removal
SS, 98% removal
BOD , 95% removal
BOD5, to 99% removal
BOD5, 90-95% removal
BOD , 90-95% removal
BOD,., 95% removal
BOD5, 90-95% removal
BOD5, to 5-10 mg/1
SS, to 3-8 mg/1
BOD5, to 10-20 mg/1
SS, to 10-15 mg/1
TDS, 90% removal
Salt, 90% removal
90-95% removal
8005, to 98% removal as
colloidal & dissolved
organic
Phosphorus, 85-95% removal
to 0.5 mg/1 or less
Salt, to 5 mg/1
TDS, to 20 mg/1
Total
Total
Total
8-28-11
-------
WATER SUPPLY
1. General industry Description
The water supply industry treats and distributes water for
domestic, commercial, and industrial use. This industry does
not distribute water for irrigation. Operations include:
coagulation, softening, iron and manganese removal, aeration,
disinfection and fluoridation.
This industry is delineated by Standard Industrial Classification
(SIC) 4941.
2. Industrial Categorization
Subcategory I - Plants that use only coagulation, oxidative
iron and manganese removal, direct filtration, or diato-
maceous-earth filtration. Only one of the above solids-
removal processes is used. Plants with combinations of two
or more solids-removal processes are included in other sub-
categories.
Subcategory II - Plants that use the lime or lime-soda
softening processes.
Subcategory III - Plants that use combinations of coagulation
and chemical softening, or oxidative iron-and-manganese
removal and chemical softening.
Zeolite softening, dissolved solids removal, and defluoridation
processes have not been subcategorized since treatment of their
wastes have not be adequately demonstrated on a commercial basis.
3. Process Description
The purpose of a water treatment plant is to remove or inacti-
vate constituents in the water that are undesirable for the
intended use. constituents that might be removed in water
treatment plants include suspended solids, pathogens, colloids,
iron and manganese, ions that cause hardness, and materials
that impart color, odor, or taste. Treatment plants that are
only required to remove one of the above are generally simple,
while treatment plants that must remove two or more of the
above constituents contain many different unit processes.
8-29-1
-------
Presedimentation - Presedimentation is used with raw waters
that contain relatively high concentrations of easily settled
suspended solids, such as sand or silt. The treatment process
consists of settling tanks with large enough detention time
to allow the solids to settle out. Wastes from this process
consist of sludges of up to 20% settled solids.
Coagulation - Coagulation is used to aid in sedimentation when
suspended particles are not readily settleable. Coagulation
(with flocculation) causes the particles to collide and
agglomerate, forming larger particles which can be easily
clarified from the solution. Materials used as coagulants
include polyelectrolytes and metal salts, such as aluminum
sulfate and ferrous sulfate. Sodium aluminate and lime are
also used when pH adjustment is desired. Wastes from these
operations are sludges containing the suspended solids removed,
plus the coagulants added. The sludges are hard to dewater,
and are generally less than 2% solids.
Softening - Softening processes used to reduce the concentra-
tion of substances that cause hardness in water (calcium and
magnesium) are of two types: chemical and zeolite. Chemical
softening consists of the use of lime to precipitate calcium
carbonate and magnesium hydroxide. Since lime alone does not
remove all of the hardness, soda ash may be used to further
reduce hardness. If iron and manganese are present they may
also be removed in the softening process. The unit operations
or chemical softening include chemical addition, rapid mixing,
flocculation, and clarification.
Zeolite softening is an ion exchange process. Natural or syn-
thetic "resins" have the capacity of exchanging ions in their
matrix with ions in solution. When the right resin is selected,
only ions associated with hardness (calcium and magnesium) are
removed from solution. When the resins have been in operation
for a period of time (6-24 hours) the resin becomes exhausted,
and must be regenerated. This regeneration waste stream is a
concentrated brine containing salts of calcium and magnesium.
Iron and Manganese Removal - Although iron and manganese are
removed in the lime softening operation, many plants need to
remove iron and manganese, but do not need to soften their
water. In these cases, iron and manganese are removed by
8-29-2
-------
oxidation (aeration) and filtration. The oxidation step can
also be accomplished with chlorine and potassium permanganate.
If the pH is too low for the precipitation of iron and manganese,
lime is added for pH adjustment, wastes from this operation
consist of filter backwashes, which contain iron and manganese
salts, and are high in color.
Filtration - Filtration is usually the final step in removing
solids regardless of the processes preceding the filtration
step. Filtration is used to remove silt, sand, colloids, viruses,
algae, bacteria, clay particles, etc. There are several types
of filters used; the most widely used is the rapid sand filter.
This filter consists of a support medium of gravel followed by
a layer of carefully sized sand. Filters can be either of the
pressure or gravity type. Wastes from filtration consist of
backwashes, which contain the particles removed by the filter,
at concentrations of 10 to 100 times their concentration in
the raw water.
Dissolved Solids Removal - Processes for removal of dissolved
solids include electrodialysis, reverse osmosis, and distillation.
Electrodialysis is a process in which many membranes are
arranged parallel to each other to form solution compartments
held between a pair of electrodes. The feed water flows
through every other solution compartment. When a voltage is
applied to the electrodes, electrolytic solids in the feed
water are transported across the membranes into a waste-brine
stream flowing between the solution compartments that contain
feed.
Reverse osmosis is a pressure-operated process in which special
membranes permit water to pass through but block impurities.
Distillation consists of vaporizing the water in the feed
solution and recondensing the pure water vapor. Wastes from
these three processes contain concentrated brine solutions.
4. Wastewater Characterization
Table 8-29-1 shows the waste characteristics for the processes
described above.
8-29-3
-------
TABLE 8-29L-1
THE WATER SUPPLY INDUSTRY
RAW WASTEWATER CHARACTERISTICS
Waste Parameter
Process
00
1
KJ
1
b.
Flow Type
BOD
TSS
TDS
COD
PH
Color
Iron
Manganese
Fluoride
Presed indentation
(sludge)
C & B
30-300
10M-200M
50-4M*
30-3M*
6-9
Present
Present
Present
0.01-3
Coagulation
(sludge)
C & B
30-300
2M-20M
50-4M*
30-3M*
6-9
Present
Present
Present
0.01-3
Chemical
Softening
C & B
30-300
10M-100M
50-4M*
30-3M*
7-11*
Present
Present
Present
0.01-3
Zeolite
Softening
B
Present
Nil
10M*-40M*
Present
6-9
Present
Present
Present
Greater
than 10
Iron and
Manganese
Removal
B
Present
1M
50-4M*
Present
6-9
Present
Present
Present
0.01-3
Filtration
B
30-300
1M
50-4M*
30-3M*
6-9
Present
Present
Present
0.01-3
Dissolved
Solids
Remova 1
C
Present
Nil
10M*-40M*
Present
6-9
Present
Present
Present
0.01-3
Notes:
M = 1.000
MM = 1,000,000
* - See Appendix 5 for parameters which may be inhibitory to biological systems
B - Batch Operated
C - Continuously Operated
-------
5. Control and Treatment Technology
In-Plant Control
Many plants use more chemicals than are required to reach the
desired effluent quality. The use of laboratory tests to
guide the plant operator in his dosage of chemicals can reduce
the amount of chemical added, and therefore reduce the
pollutant load of the waste from the plant.
The use of organic polymers in place of inorganic coagulants
reduces the amount of waste solids generated, and produces a
sludge that is more easily dewatered. In addition, the polymers
are biodegradable.
Recycling of filter backwash can greatly reduce the amount of
wastewater produced by a water treatment plant. Since filter
backwashes are low in solids compared to sludges, recycling of
the backwash water to the head end of the plant, and letting the
initial clarifier remove the suspended solids from the back-
wash water eliminates a waste stream. The backwash water
should be placed in a detention tank and bled slowly to the
head end of the plant. This detention tank can also be used for
clarifying the backwash water.
Chemical recovery can also be used as an in-plant control
measure. Alum can be recovered by thickening the alum sludge
to greater than 2% solids, adding sulfuric acid to dissolve
the aluminum, dewatering of the sludge which recovers the
aluminum as alum, and then reusing the alum.
Lime is recovered by burning the calcium carbonate sludge from
the lime softening clarifier in a furnace, which produces
calcium oxide. Calcium oxide is then slaked in water,producing
lime. Magnesium hydroxide must be removed before the burning
process.
Treatment Technology
The sludges may be handled by equalization and storage. This
can be accomplished by thickening of the sludge, which reduces
its volume. Thickening prior to sludge dewatering reduces the
size of the sludge dewatering equipment.
8-29-5
-------
Prior to sludge dewatering, sludge conditioning with organic
polymers is generally practiced in order to aid in the
dewatering step. Dewatering systems include lagoons, vacuum
filtration, filter presses, and centrifuges. Lagoons are
the most popular and the cheapest to run, but require large
land areas.
8-29-6
-------
MISCELLANEOUS FOODS AND
BEVERAGES
1. General Industry Description
This industry includes establishments engaged in the manufacture
of vegetable oils, beverages (alcoholic and non-alcoholic),
bakery and confectionary products, pet foods and miscellaneous
specialty food products. The general category includes approxi-
mately 10 percent of U. S. industry and 60 percent of the food
processing industry in terms of number of industrial establishments.
In general, wastes from this industry are non-toxic, biodegradable
and amenable to standard sewage treatment processes. One excep-
tion is the nickel catalyst from the hydrogenation of edible oils
which is potentially detrimental to anaerobic digestion systems.
However, presently this problem does not generally exist, and
nickel levels in wastewaters are infinitesimal to nonexistent.
High suspended solids and the oil and grease content of some
wastewaters may require that pretreatment be employed for
removal of the floatable grease fraction prior to effective
biological treatment. Because of the sometimes cyclic nature
of waste production in this industry, flow equalization is often
required to dampen shock loadings.
These establishments are covered by the following Standard
Industrial Classifications (SIC):
2017, 2034, 2038, 2047, 2050, 2052, 2665, 2066, 2067, 2674,
2075, 2076, 2079, 2082, 2083, 2084, 2085, 5182, 2086, 2087,
2095, 2097, 2098, 2099, 5144, 5182
2. Industrial Categorization
A useful categorization for the purpose of raw waste character-
ization and the establishment of pretreatment information is
the following:
a. Vegetable Oil Processing and Refining
b. Beverages, Alcoholic and Non-alcoholic
c. Bakery and Confectionary Products
d. Pet Foods
e. Miscellaneous and Specialty Products (listed in industry
description)
3. Process Description
Vegetable Oil Processing and Refining
Vegetable oils are produced from soya beans,cotton, flax, peanuts,
olives, sunflower and safflower seeds. The seed is crushed,
the oil extracted and refined, and sold for use as shortening,
salad and cooking oils, mayonnaise and margarine. Oil is generally
8-30-1
-------
extracted from the seed by screwpress expression, hydraulic
press or by extraction with some type of solvent (usually hexane).
The refining operation involves a complex series of processes
intended to remove contaminants, bleach out colors, filter out
taste and odors, and to impart to the neutral oils the desired
qualities of plasticity, texture, etc. Unit processes include
storage and handling caustic refining, bleaching, deodorization,
acidulation, winterization, hydrogenation, and plasticizing for
margarine.
The major sources of wastewater are acidulation of foots from
caustic refining, deodorization, storage and handling, and tank
car cleaning. The spent flakes are dried and reprocessed as oil
seed meal for eventual sale as animal feed and protein supplement.
Beverages
Malt Brewing
The malt brewing industry produces beer, ale, and malt liquors
by fermentation of sugars converted from the starch of various
grains i.e. barley,rice,wheat and corn. Grain starch is converted
to malt sugar and then to alcohol by mashing, brewing and ferment-
ing. The product is aged, filtered, packaged and marketed.
Ground grains are mixed with a ground malt slurry in a mash
cooker and lightly boiled. The mixture is filtered. The spent
grain waste is sold as feed and the "extract" goes to brewing.
Wastewaters include liquor from the spent grain, rinse and clean-
up waters.
In the brew kettle the extract is boiled and mixed with hops to
produce a liquor called "wort" This hot extract is filtered
and sent to fermentation. The spent hops, and "trub" (the
insoluble settlings from the hot wort), are added to the spent
grains. Spent filter media is hauled away for landfill.
Yeast is added to cooled wort in fermentation tanks where malt
sugars are converted to alcohol and carbon dioxide. After
aging,the beer is filtered for clarity. The beverage is
packed in cans, bottles, and barrels. Lost beer and alkaline
washwater are the principal wastes.
Wastewaters are generated from washups. The spent grain from
the mashing step may be (1) sold wet (2) screened, pressed as
dry as possible, and fire-dried, with the spent grain liquor
sewered or (3) screened, pressed and fire-dired with the spent
grain liquor concentrated (20-30% solids) in a multi-effect
evaporator. The wastes from the grain mashing operating are
often the major portion of the plant's waste load.
8-30-2
-------
Malt Manufacture
In this industry barley is converted to malt which is the primary
enzyme - producer for starch conversion. The process steps
required after cleaning and grading of the grain are:
Steeping - soaking grain in water imparts moisture to grain and
washes out colors and tannins. The wash water changes are a
major waste.
Germinating - Storing steeped barley in warm, moist atmosphere
creates enzymes in grain. Water drained from storage compartments
is a source of significant waste.
Kilning - Drying malt to specific moisture content. No waste-
waters are generated in this process.
Wines, Brandy and Brandy Spirits
Wines are produced in two general classes: (1) table wines
(unfortified) which include the still and sparkling varieties
(2) dessert wines and spirits, which are fortified with wine
spirits. The wine making process is seasonal, beginning in
September and October with gathering, de-stemming and crushing
of grapes. The juice, skins and seeds, known as MUST, are fermen-
ted for 6 to 8 weeks with an initiating yeast and then screened
after color and tannins are sufficiently developed. Clarifica-
tion and filtration constitute the finishing operations. The
residual solids are used as vineyard mulch or poultry feed.
Bottling, labeling and casing are the final operations and they
produce little waste except for breakage.
Wastewaters from this portion of the industry are principally
from equipment washdowns and occasional spills.
Wineries that distill wines to produce wine spirits or brandy
have as their major waste, "stillage", the bottoms from the
alcohol stills. Stillage can be concentrated in multi-effect
evaporators and the residue hauled away or disposed of in evapora-
tion ponds.
Grain Spirits
Distilled, Rectified and Blended Liquors
Various grains and barley malt (enzymes) are mashed, fermented,
distilled, aged, and rectified to produce whiskey, vodka, gin,
and rum. Cordials and liqueurs are produced by blending. The
processes are similar to those of malt beverage production with
the addition of distillation and rectification.
8-30-3
-------
Over 80% of the distillery waste is the result of the recovery
of spent stillage. Some distilleries dispose of the stillage
as is, but most recover it by concentration and drying for cattle
feed. Evaporator condensate is a significant source of wastewater.
Molasses distilleries ferment molasses to produce rum. Either
cane or citrus molasses is fermented with phosphorous and ammonia
nutrients, and yeast to produce a mash. The mash is separated
by distillation into rum, amyl oils, and chemical by-products
including aldehydes and esters. The chemicals are burned as
fuel, the oils are sold, and stillage handling has been previously
discussed.
Bottled and Canned Soft Drinks
This industry combines concentrated flavorings, color, sweetener,
carbonation and water, and packages the final product. Wastewaters
are generated from equipment clean up, spills and bottle washing.
Roasted and Soluble Coffee Processing
Coffee beans are air cleaned, blended, roasted, and marketed
as either a ground bean or soluble powder product. Beans may
be decaffeinated before roasting by either an organic solvent
or a hot water extraction process. They are then rinsed, dewatered,
dried and prepared for roasting.
Wastewaters are generated in washing decaffeinated beans, in flush-
ing of the extract centrifuge and in the solvent and caffeine
separation process.
Soluble coffee production begins with the passing of hot water
through a series of column extractors to extract the soluble
materials from freshly roasted and ground coffee beans. The
resulting 20-30% solids extract is cooled and then clarified by
centrifugation or filtering; later it is usually concentrated to
40% by evaporation or by freeze concentration for more efficient
spray or freeze drying. Spent grounds and the residual water
associated with the grounds are significant wastes. The grounds
are dewatered and landfilled or they are dried for use as boiler
fuel; the wastewater that is pressed out of spent grounds is
discharged with the cleanings from centrifuges or filters. Other
waste sources are the general washdown of the extractors, sludge
from the centrifuges or filters, the scaling tank, the heat exchanger
and the holding tank. The drying operations produce only cleaning
wastewaters.
8-30-4
-------
Coffee
Spent groundg are often dewatered, and the grounds are used as
boiler fuel, or landfill. The residual water from spent
grounds pressing is a significant wastewater source. Color
is also a potential problem from coffee and tea wastes,
and activated carbon has shown some potential in the treatment
of organic color problems.
Bakery and Confectionary
Conventional bread baking involves a number of dry operations:
sifting, mixing, cutting,shaping and baking. This batch system
is amenable to dry cleaning techniques and generates little
wastewater. On the other hand, newer continuous methods generate
considerable amounts of wastewater. In this process, the ingredients
are slurried, pumped, extruded and baked. Since the mixture is
liquid in much of the process, the equipment must be wet cleaned
daily and wastewaters are produced.
Cake production involves high waste generating operations includ-
ing icing, filling and dusting. Frequent equipment washups
are required.
In the production of confectionary products the ingredients are
usually mixed, cooked, cooled and aerated. Wastewaters generally
are limited to equipment washups.
Pet Foods Industry
Canned, dry, semi-moist pet foods are produced from meat and
meat by-products, fish and fish by-products, grains and other
additives. The raw materials are blended, cooked and packaged.
Dry pet food is prepared by subjecting the materials to an
extrusion/expansion process. Daily cleanups and general house-
keeping generate wastewaters that contain high BOD and suspended
solids. A substantial waste load is generated in the packing
and canning of meat based pet foods, since the cans are over-
filled prior to sealing.
Miscellaneous and Specialty Products
A large number of items are contained under this heading. Most
of them are of a diverse nature and have little relationship
to each other with respect to processing, waste characteristics
etc. Products included in this group with a significant waste-
load are eggs and egg breaking, yeast, hydrolyzate, frozen
specialty products,instant tea, bouillon and dehydrated soups,
pectin, vinegar, etc. Others having dry processes or insignificant
discharges include baking powder, spices, chicory, bread crumbs,
non-dairy coffee creamer, peanut butter, manufactured ice, sand-
wiches, spices, popcorn, desserts, etc.
8-30-5
-------
Pectin, hydrolyzates, instant tea, and yeast generate extremely
high waste loads and high volumes. An essential in-plant control
for hydrolyzates, yeasts, oil seed extraction, instant coffee,
instant tea, egg breaking, etc. is in the separation and alter-
nate disposal of filter cake wastes, condensate underdrains, egg
shells, and spent tea leaves. Filters,centrifuges, floatable
oil recovery systems, and equalization should be considered as
viable in-plant control for most of the miscellaneous and
specialty products.
Pectin production, however, generates a high BOD waste. Pectin
is a water soluble substance contained in the peel of citrus
fruit and used in the preparation of fruit jellies and pharmaceu-
ticals. It is recovered by one of two complex processes, both
significant wastewater sources.
4. Wastewater Characterization
Table 8-30-1 contains wastewater characteristics for this
industrial group.
5. Control and Treatment Technology
In-Plant Control
Water conservation practices, i.e. high pressure sprays, water
meters and segregation of waste streams to enable water reuse
can minimize wastewater production. Good housekeeping practices
that reduce spills and leaks can reduce washups. The sub-
stitution of dry cleanups for water cleanups can significantly
reduce the waste load.
Spent grain liquor can be eliminated by direct drying of the
grain solids and evaporation of lost beer.
Waste reduction in the manufacture of malt depends upon good
control of steep water and maintaining a close spray and
refrigeration cycle so that only makeup is needed.
Some wineries have reduced waste volumes by the reuse of clean-
ing water and by omitting live steam which reduces stillage
15%.
Grain and molasses distillers have reduced wastes by replacing
barometric condensers with surface type or mash cookers, coolers
and evaporators. Stillage volume can be reduced by substituting
indirect heating for live steam injection.
8-30-6
-------
Treatment Technology
Wastes from these industries are generally treated by conven-
tional biological and physical-chemical methods. Because dis-
charges may be intermittent,/ equalization is often required.
Some wastes may be pretreat'ed before discharge to the municipal
sewer in order to lighten the organic biodegradable load.
Treatment methods used by the industry include the following:
Pollutant Treatment Method
BOD
Suspended Solids
Oil and Grease
Color
Nickel
Biological Treatment
Spray Irrigation/land application
Flocculation with lime
Activated carbon
Filtration and settling
Centrifugation
Dissolved Air Floatation
Grease traps
Sump decanters
API separators
Gravity separators
Activated carbon
Lime precipitation
Filtration
Filtration
8-30-7
-------
TABLE 8-30-1
MISCELLANEOUS FOODS AND BEVERAGES
RAW WASTEWATER CHARACTERISTICS (MG/L)
CD
I
U)
O
I
GO
Subcategories Flow(GPP)
Oil Seed Crushing
(except olive oil)
Olive Oil Extraction
Oil Refining
Malt Beverages 70QM-8MM
Wineries 70M-100M
Grain Distillers 25M-600M
Molasses Distillers 215
Soft Drink 125
Coffee & Tea 70M-180M
Bread & Confectionary 20M-240M
Cake 40M-120M
Pet Food 20M-180M
Miscellaneous 200-700M
BOD
340
30M*-60M*
2M*-7M*
1.4M-2M*
1.2M*-5.8M*
200-950*
35M*
600-2400*
350-2400*
400-1300*
2M*-28M*
200-12M*
1M*-6M*
GOD
815
3M*-20M*
SS
210
15M-57M
1M-3M
500-700
400-5.7M
200-650
6.7M
50-100
700-1500
100-400
1M-5M
200-9M
130-1.9M
Oil/Grease
380*
3M*-20M*
500*-4M*
30-170
500-685
Notes: M - thousand
MM - million
* See Appendix 5 for parameters which may be
inhibitory to biological systems.
-------
MISCELLANEOUS
CHEMICALS
1. General Industry Description
The miscellaneous chemicals industry encompasses a wide range
of chemical products, utilizing many different raw materials
and unit operations and generating wastewaters with varied
characteristics. In general, wastewaters contain BOD, COD,
TSS, and metals. This industry includes Standard Indus-
trial Classifications(SIC) 2831, 2833, 2834, 2861, 2879, 2891,
2892, 2895, 2899, 7221, 7333, 7395, 7891, 8062, 8063, 8069.
2. Industrial Categorization
This industry has been divided into the following
subcategories:
Major Category
Pharmaceuticals
Gum and Wood Chemicals
Pesticides and Agricul-
tural Chemicals
Adhesive and Sealants
Subcategory
Fermentative products
Biological and Natural Extraction
products
Chemical Synthesis Production
Mixing/Compounding or Formulation
Research
Char and Charcoal Briquets
Gum Rosin and Turpentine
Wood Rosin, Turpentine and Pine Oil
Tall Oil Rosin, Pitch and Fatty Acids
Essential Oils
Rosin Derivatives
Halogenated Organic Pesticides
Organo-Phosphorus Pesticides
Organo-Nitrogen Pesticides
Metallo-Organic Pesticides
Formulators and Packers
Animal Glue and Gelatin
Water-Based Adhesives
Solvent-Base Adhesives
Hot Melt Thermoplastic Adhesives
Dry Blend Adhesives
8-31-1
-------
Manor Category Subcateqory
Explosives Manufacture of Explosives
Manufacture of Propellants
Load and Pack Plants
Specialty Plants
Carbon Black Furnace Black
Thermal Black
Photographic Processing Photographic Processing
Hospitals Hospitals
3. Process Description
Pharmaceutical Industry
Figure 8-31-1 contains flow diagrams for the production of
Pharmaceuticals by processes of fermentation, formulation and
biological culture.
Fermentation Processes
Fermentation is an important production process in the Pharma-
ceutical Industry. This is the basic method used for producing
most antibiotics (penicillin, streptomycin, etc.) and many of
the steroids (cortisone, etc.). The product is produced in
batch fermentation tanks in the presence of a particular fungus
or bacterium. The culture may be the product, or it may be
filtered from the medium and marketed in cake or liquid form
as animal feed supplement. The product is extracted from the
culture medium through the use of solvents, activated carbon,
etc. The antibody is then washed to remove residual impurities,
concentrated, filtered and packaged.
The most troublesome waste of the fermentation process, and the
one most likely to be involved in water pollution problems, is
spent beer. This is the fermented broth from which the valuable
fraction, antibiotic or steroid, has been extracted. Spent
beer contains a large amount of organic material, protein, and
other nutrients. Although spent beer frequently contains high
amounts of nitrogen, phosphate, and other plant growth factors,
it is also likely to contain salts, like sodium chloride and
sodium sulfate, from the extraction processes.
8-31-2
-------
CHICK
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FIGURE 8-ai-l
PHARAMACEUTICAL IEDUSTRY
MISCELLANEOUS CHEMICALS
8-31-3
Vaccine Production
Fermentation Process
Formulation Process
-------
This subcategory includes the unit operations which follow the
fermentation steps that are used to retrieve the product from
the fermentation broth. These include physical separation
steps, such as vacuum filtration and centrifugation, as well
as chemical separation via solvent extraction and distillation.
Fermentation requires extensive quantities of water. The
primary liquid wastes include the fermentation beers; inorganic
solids, such as diatomaceous earth, which are utilized as a
pre-coat or an aid to the filtration process; floor and equip-
ment washings; chemical wastes such as solvents; and barometric
condenser water from evaporation.
Biological and Natural Extraction Process
Biological Product Manufacturers produce bacterial and virus
vaccines, toxoids and analogous products (such as allergenic
extracts), serums, plasmas, and other blood derivatives for
human or veterinary use. The primary manufacturing steps in
blood fractionation include chemical precipitation, clarifi-
cation, extraction, and centrifugation. The primary wastewater
sources are precipitates, supernatants, centrates, waste
alcohols, and tank washings. The precipitates and waste
alcohols can be incinerated or reclaimed, while dilute wastes
(supernatants, centrates, and tank washings) are sewered. The
production procedures for vaccines are generally lengthy and
involve numerous batch operations. Unit operations include
incubation, centrifugation, staining, freezing, drying, etc.
Liquid wastes associated with the process consist primarily of
spent media broth, waste eggs, glassware and vessel washings,
animal wastes, bad batches of production seed and/or final
product, and scrubber water from air pollution control equip-
ment. Spent media broth, bad batches, waste eggs, animal
carcasses, and contaminated feces are normally incinerated.
Wastes from small non-infected control animals may be land-
filled. Equipment washings, animal cage washings, and scrubber
blowdowns are usually sewered.
Natural extractions manufacturing includes the processing
(grading, grinding, and milling) of bulk botanical drugs and
herbs. Establishments primarily engaged in manufacturing agar
and similar products of natural origin, endocrine products,
manufacturing or isolating basic vitamins, and isolating active
medicinal principals such as alkaloids from botanical drugs
and herbs are also included in this industry. The primary
8-31-4
-------
wastewater sources include floor washings, residues, equipment
and vessel wash waters and spills. To the maximum extent
possible, bad batches are corrected rather than discarded.
When bad batches cannot be corrected, liquids are generally
discharged to the plant sewer system. Solid wastes are usually
landfilled or incinerated.
Chemical Synthesis
The production of chemical synthesis products is very similar
to fine chemicals production, and uses the following major
unit processes: reaction, extraction, concentration, separation,
solvent recovery, and drying. The synthesis reactions are
generally batch types which are followed by extraction of the
product. Extraction of the pharmaceutical product is often
accomplished through solvents. The product may then be washed,
concentrated and filtered to the desired purity and dried.
The major wastewater sources include tank washes, equipment
washes, spent cooling water, and condenser discharges. These
wastes are generally amenable to biological treatment.
Mixing/Compounding or Formulation
Formulation operations for synthesis products may be either dry
or wet. Dry production involves dry mixing, tableting or cap-
suling, capsule manufacturing, and packaging. Process equip-
ment is generally vacuum cleaned to remove dry solids, and then
is washed down. Scrubber blowdown from air pollution control
devices may also be a wastewater source. The primary waste-
water sources include equipment washings and spills.
Research
Research facilities do not produce marketable products but
generate wastewaters from equipment washings and animal cage
washwaters. A common problem is the disposal of flammable
solvents which can result in explosions and fires.
Gum and Wood Chemicals
Char and Charcoal Briquets
Char or charcoal is produced by the carbonization of wood,
which is the thermal decomposition of raw wood. During the
decomposition of the wood, distillates are formed and leave
8-31-5
-------
the kiln with the flue gases. The condensable distillates
are called pyroligneous acids which contain methanol, acetic
acid, acetone, tars, oil, and water. This distillate may be
recovered or burned. No process wastewaters are generated.
Gum Rosin and Turpentine
The crude gum raw material is obtained by gum farmers who
collect the gum from pine trees. The gum is filtered to remove
impurities and then distilled to separate the turpentine.
Wastewaters are produced from crude gum wash, still condensate,
and dehydration of brine operations. Wastes contain BOD and
COD.
Wood Rosin, Turpentine and Pine Oil
These materials are manufactured from stumps obtained from
cut-over pine forests. The stumps are washed and reduced to
wood chips and then the products are extracted and steamed
from the chips. Washwaters are recycled. Only condensate
wastewaters are produced containing BOD and COD. Figure 8-31-2
is a flow diagram for this process.
Tall Oil Rosin, Fatty Acids and Pitch
These products are produced by distillation of crude tall oil,
a chemical wood pulp by-product, in an operation similar to
oil refinery distillation. Very few process wastes are
produced. The major waste flow is from non-contact cooling
water.
Pesticides and Agricultural Chemicals Industry
Pesticide plants which manufacture active ingredient products
use many diverse manufacturing processes. Rarely does a plant
employ all of the processes found in the industry, but most
plants use several in series. The principal processes utilized
include chemical synthesis, separation, recovery, purification
and product finishing, such as drying.
Chemical synthesis can include chlorination, alkylation,
nitration, and many other substitutive reactions. Separation
processes include filtration, decantation, and centrifuging.
8-31-6
-------
Figure 8-31-2
WOOD ROSIN PINE OIL. AND TURPENTINE PRODUCTION VIA SOLVENT EXTRATION
TO STILL
-------
Recovery and purification are utilized to reclaim solvents or
excess reactants as well as to purify intermediates and final
products. Evaporation, distillation, and extraction are
common processes in the Pesticides and Agricultural Chemicals
Industry. Product finishing can include blending, dilution,
palletizing, packaging, and canning.
In the manufacture of halogenated organic pesticides, the
principal sources of high organic wastes are decanting, dis-
tillation, and stripping operations. Sources of wastewater
from the manufacture of organo-phosphorus pesticides include
decanter units, distillation towers, overhead collectors,
solvent strippers, caustic scrubbers, contact cooling, hydro-
lyzing, and product and equipment washing. Sources of waste-
waters from the manufacture of organo-nitrogen and metallo-
organic pesticides are similar to the two other products
mentioned above.
Adhesive and Sealants
The manufacturing processes for all subcategories within the
industry are basically the same. From one-man garage-type
operations to large industrial complexes, the manufacturing
process consists of mixing or compounding the various components
in batch mix tanks or kettles.
Both water base and organic solvent base adhesives are produced
by mixing the raw materials in mixing tanks under ambient
temperatures or heating the tank contents with steam. The
non-solvent base adhesives (thermoplastic and dry-blend adhesives)
are produced in mixing tanks also. Thermoplastic adhesives
require heat while dry-blends do not. All production processes
described above are batch processes. The one exception is
animal glue production, which involves hot water applications
for the extraction of glue from the raw materials.
Solvents are needed in most adhesives to disperse the binder
to a spreadable liquid form. In most wood-and paper-bonding
adhesives the solvent is water. In many adhesives based on
synthetic resins, rubbers, and even natural gums, a variety
of organic solvents are required to achieve the necessary
solubility and to provide some minimum percentage of base
solids. However, thermoplastic adhesives and dry blended
adhesive materials are composed completely of solids and con-
tain neither water nor solvent-based materials. Polymeric,
8-31-8
-------
thermoplastic solids are converted to mobile fluids when
subjected to sufficient amounts of heat.
The main source of wastewater is the washing of the process
vessels and lines. Most adhesive industries discharge to
publicly-owned treatment works. Wastes are high in BOD, COD
and TSS.
Explosives
The general production process for the manufacturing of explosives
involves the nitration of an organic molecule. Raw materials
used in this process are nitric acid, acting as the nitrate
source, and sulfuric or acetic acid, acting as a dehydrating
agent. Examples of the organic molecules used are glycerin,
toluene, resorsinol, hexamine and cellulose. After nitration,
these organic molecules produce the following products: nitro-
glycerin and dinitroglycerin; trinitrotoluene and dinitro-
toluene; trinitroresorscinol; nitromanite; and nitrocellulose,
respectively. Additional production processes involve the
formation of highly sensitive initiators with nitrogen salts
as a nitrogen source. An example of this product would be
lead azide.
Wastewaters are generally very low in pH and can be high in
BOD, COD and nitrates. Wastes can also contain concentrations
of the explosives produced.
Figure 8-31-3 is a flow diagram for the nitroglycerin manu-
facturing process.
Carbon Black
The manufacturing processes used to manufacture carbon black
consist of the furnace, thermal, channel, and lamp black
processes. The final product from each of these processes is
carbon black, differing only in particle size and structure.
Furnace black is produced by the incomplete combustion of
hydrocarbons. The raw materials consumed in the manufacture
of carbon black consist of hydrocarbons. Liquid hydrocarbons
are used in the furnace process. The most desirable feed stock
oil for the furnace process comes from near the bottom of the
refinery barrel and is similar in many respects to residual
fuel oil. It is low in sulfur and high in aromatics and
olefins. This process is a net user of water and generally
has no process contact wastewaters.
8-31-9
-------
FIGURE 8-31-3
TYPICAL IMITROGLYCERIIM PRODUCTION SCHEMATIC
NITRATOR
NG-ACID
MIXTURE
GRAVITY
SEPARATOR
NG
SPENT ACIDS
TO RECOVERY
OR
NEUTRALIZER
WASTE WATER.
GLYCERIN PLUS
ETHYLENE GLYCOL
NITRIC PLUS
SULFURIC ACIDS
WASH
TANK
(WATER)
NG
WATER
NEUTRALIZER
TANK
SODIUM
CARBONATE
SOLUTION
NG
CATCH
TRAP
SODIUM
CARBONATE
NG
NEUTRALIZER
TANK
H20
FINAL
WASH
NG
8-31-10
-------
Thermal blacks are produced by cracking of natural gas to
form carbon and hydrogen gas. The major wastewater source
from this process is the blowdown from a recirculating
dehumidifier system.
Channel black is produced by impingement of under-ventilated
natural gas flames on moving, continuously scraped channels.
Lamp blacks are manufactured by the burning of petroleum or
coal tar residues in open shallow pans.
Photographic Processing
Most commercial photoprocessors handle many square feet of
film and paper with automatic processing machines. The basic
machines are called the "dip and dunk" or "rack and tank" types,
which consist of a series of tanks with each tank containing a
photoprocessing solution. These solutions impart the desired
effect on the film or paper in each progressive step of develop-
ment. Continuous length processors are used by most large
firms, and roller transports are used in graphic arts and
for hospital X-ray films.
During photoprocessing, many changes occur within the processing
solutions. Because of these changes, the chemicals used in
photo-processing need to be replaced, strengthened or replenished.
Developing agents become oxidized and exhausted; developer
activators and preservatives wear out; anti-foggants become
used up; bromides or other halides resulting from the reduction
of the silver by the developer become more concentrated; acid
short stops become neutralized; and the removal of silver from
the emulsion causes increased concentrations of silver in the
fixers or hypo baths. Chemicals are added to maintain the
correct chemical strength and photographic properties. When a
replenisher is added, its volume must be sufficient to cause
enough overflow of the unwanted by-products. Overflows from
the processing tanks caused by the addition of replenishers
and wash water overflows are the two sources of effluent from
photoprocess ing.
Process wastewaters include both photoprocessing solution over-
flows and washwaters; together, these spent waters are high in
BOD, COD, TOG, TDS, silver and cyanide. Generally, the
8-31-11
-------
pollutants of significance are the same for both color and
black and white photofinishing operations with the exception
of ferrocyanide which is generated during the bleaching step
in color development.
Hospitals
The three major areas in a hospital which generate wastewaters
are patient rooms, laundries, and cafeterias. Sanitary flows
are the primary wastes from hospital patient rooms and,
obviously, the more beds a hospital has, the more significant
this flow will be. Cafeterias are another large contributer
to the wastewaters generated by hospitals. The cleaning of
foodstuffs, preparation of meals, washing of dishes, and floor
and equipment cleaning are all activities which generate
wastewaters from a cafeteria. These wastes usually contain
organic matter, in dissolved and colloidal state, and oils and
greases in varying degrees of concentration. The third major
contributor of wastewaters in a hospital is laundries. Laundry
wastes originate from the use of soap, soda, and detergents in
removing grease, dirt, blood, and starch from soiled clothing
and linen. Laundry wastes generally have a high turbidity,
alkalinity, and BOD content.
Three other areas in a hospital which discharge smaller
quantities of wastewaters are surgical rooms, laboratories,
and X-ray departments. Surgical room wastewaters are primarily
washwaters from cleaning activities. Laboratory wastes
generally consist of solvents, glassware washwater, and various
reagents used in the laboratory. Research hospitals may also
have animal cage washings in their laboratory wastes. X-ray
departments are an additional source of wastewaters. These
wastes consist of spent solutions of developer and fixer,
containing thiosulfates and compounds of silver. The solutions
are usually alkaline and contain various organic reducing
agents. Most hospitals recover the silver from spent X-ray
film developing solutions. All pathological wastes from
surgical suites are collected and disposed of in hospital
pathological incinerators.
Some hospitals generate radioactive wastes from diagnostic and
therapeutic uses. Iodine-131 and phosphorus-32 are the radioiso-
topes which predominate in hospital radioactive wastes.
8-3 1-12
-------
Fortunately, these possess short half-lives, and simple
detention tanks can render them inactive. The handling of
radioactive waste is closely monitored by AEG, and these
wastes are not discharged to the hospital sewer system.
4. Wastewater Characterization
Tables 8-31-1 through 8-31-6 provide waste characterization data
for the industries covered in this description.
5. Control and Treatment Technology
In-Plant Control
Pharmaceutical Industry - Good housekeeping consists of the
use of dry cleaning techniques (vacuum cleaning) in place of
wet systems, separate containment of toxic substances, and
containment of spills and storm water.
Other in-plant controls consist of the following:
1) The replacement of water sprays with exchangers in
barometric condensers.
2) Recycling of water used in water sealed pumps.
3) Recovery of waste solvents, and other chemicals.
4) Reuse of wastewaters (e.g. cooling water).
Gum and Wood Chemicals - Specific in-plant control measures
have not been identified for this industry.
Pesticides and Agricultural Chemicals - Waste segregation is
an important in-plant control measure, since high organic
loading streams will require different treatment schemes than
low organic loading streams. The use of dry cleanup systems
can also reduce wastewater flows. Steam jet ejectors and
barometric condensers can be replaced in most cases with
vacuum pumps and surface condenser systems.
Adhesive and Sealants - Some in-plant controls that are applic-
able to this industry are:
1) Rinse recycle to reduce rinse water volumes.
2) Recovery of by-products, that can be sold instead of
discharged as a waste stream.
8-31-13
-------
TABLE 8- 31-1
PHARMACEUTICAL INDUSTRY
RAW WASTEWATER CHARACTERIZATION
PARAMETERS (mg/1)
SUBCATEGORY
Flow, GPD
Flow Type
BOD
TSS
CO
ioTDS
£ COD
*" TOC
Cyanide
PH
Color
Detergents
Metals
Fermentative
Products
80M - 500M
B
4M*- lift*
800 - 7M
High
9M* - 15M*
1.8M - 10M
4* - 8
Avg - High
Present
Biological and
Natural Extraction
Products
20M - 200M
100-600
10 - 50
400 - 1M*
30 - 200
6* - 8
Chemical Mixing and
Synthesis Compounding
30M - 1.5MM 10M - 400M
B
500 - 5M* 250 - 2M*
200 - 900 100 - 500
Avg - High
3M* - 10M* 500 - 4M*
900 - 3M
Present
200 - 900
6*- 8
Research
20M - 300M
100 - 300
200 - 500
200 - 600
50 - 150
6*- 8
Avg - High
Present
Present
Notes:
M = 1,000
MM = 1,000,000
B - Batch Process
* See Appendix 5 for parameters which may be inhibitory
to biological systems
-------
TABLE 8-31-2
GUM AND WOOD CHEMICALS INDUSTRY
RAW WASTEWATER CHARACTERIZATION
PARAMETERS (mg/1)
SUBCATEGORY
co
I
co
i-j
I
H<
Ul
BOD
TSS
TDS
Color
Nitrogen (Kjeldahl)
Oil and Grease
Zinc
Phenol
Char and
Charcoal
No
Process
Flow
1
Gum Rosin
and
Turpentine
140
3600*
200
30
400*
15*
Wood Rosin,
Turpentine
& Pine Oil
30
700
100
5
50*
Tall Oil Rosin,
Pitch, Fatty Acids
0
650
40
0
300*
20
Essential
Oils
6
50
-
10
0.5
Rosin
Derivatives
50
7300*
-
13
360*
7*
60
Notes: * See Appendix 5 for parameters which may be inhibitory to biological systems,
-------
TABLE 8-31-3
PESTICIDES AND AGRICULTURAL CHEMICALS
RAW WASTEWATER CHARACTERISTICS
PARAMETERS (mg/1)
SUBCATEGORY
Halogenated Organic Organic Metallo-
Organic Phosphorus Nitrogen Organic
Pesticides Pesticides Pesticides Pesticides
BOD 125 - 8.5M* 140 - 750* 1 . 2M* - 2 . 5M* 20 - 800*
oo TSS 100 - 250 10 - 100 10 - 2M 1.5M - 3M
OL)
£ COD 850 - 16M* 350 - 1.8M* 800 - 15M* 1.5M*- 2.2M*
TOC 650 - 8.4M 100 - 4M 450 - 5.3M 80
TDS 2M* - 44M*
Notes: M = 1,000
Formulators
and Packers
150 - 1.6M*
100 - 650
500 - 6M*
-
MM = 1,000,000
* See Appendix 5 for parameters which may be inhibitory
to biological systems.
-------
TABLE 8-31-4
ADHESIVE AND SEALANTS
RAW WASTEWATER CHARACTERISTICS
S UBCATE- GORY
CO
1
U>
I-1
(- *
^J
PARAMETERS (mq/1)
Flow, GPD
BOD
TSS
COD
TOC
PH
Nitrogen-NH
Chromium
Oil and Grease
Animal Glue
and Gelatin
3MM
1.2M*-4.8M*
1.7M -4.5M
10M*
2.6M
9-12*
16
10*-20*
400*-1.5M *
Solvent Based Solvent Based Hot Melt
Adhesives Adhesives Thermo- Dry
Water Based w/Contaminated w/o Contaminated Plastic Blend
Adhesives Water Water Adhesives Adhesives
3M-10M 6M
2.1M*-4.2M* 13M*
2.1M -4.3M 36
16M* 22M*
3.8M -7.7M 4.2M
9
5-20 20
70M-350M No No
No Contaminated Waste Waste
Waste Water Flow Flow
Notes:
M = 1,000
MM= 1,000,000
* See Appendix 5 for parameters which may be inhibitory
to biologiqal systems
-------
CD
I
U>
Y
\->
CO
PARAMETERS (mq/1)
BOD
TSS
COD
TOC
PH
Nitrogen(nitrate)
Explos ives
TABLE 8-31-5
EXPLOSIVES INDUSTRY
RAW WASTEWATER CHARACTERISTICS
SUBCATEGORY
Manufacture
of Explosives
20 - 1M*
10 - 1.3M
60 - 3.4M*
12 - 1.5M
Variable
25 - 7M*
Present
Manufacture
of Propellants
200
100 - 1M
200 - 1.2M*
30 - 130
Variable
1 - 4M*
Present
Load and
Pack Plants
1M*
1 - 700
8 - 8.5M*
5 - 550
Variable
.4 - 12
Present
Specialty
Plants
1M* - 12M*
1 - 60M
11M*- 50M*
5.7M
Variable
.5 - 5M*
Present
Notes:
M = 1,000
MM = 1,000,000
* See Appendix 5 for parameters which may be inhibitory
to biological systems
-------
TABLE 8-31-6
CARBON BLACK, PHOTOGRAPHIC, AND HOSPITAL INDUSTRIES
RAW WASTEWATER CHARACTERISTICS
oo
i
U)
}-
I-1
\o
PARAMETERS (mq/1)
BOD
TSS
TDS
COD
TOC
Cyanide
Nitrogen(Kjeldahl)
Iron
S ilver
Boron
SUBCATEGORY
Carbon Black
Industry
NO
Data
Photograph ic
Industry
300
25
2,000*
1,000
300
6*
100
20*
005
18*
Hospitals
100-400
60-200
300-800
100-300
Notes
M = 1,000
MM = 1,000,000
See Appendix 5 for parameters which may be inhibitory
to biological systems
-------
3) Minimize equipment washouts.
4) The use of steam instead of water reduces the wastewater
volume.
Explosives Industry - Many products are manufactured by a dry
process, so that the only waste streams come from cleanup
of spills and leaks. Dry cleanup systems should therefore
be used.
In many plants, water is used to transport the material throughout
the facility, and to purify the product. This water need not
be of high quality, and recycle can reduce the waste produced
from this operation. Separation of contact and non-contact
waters can reduce the size of treatment systems, and the volume
of flow discharged.
Carbon Black Industry - Due to the competitive nature of this
industry, product and water recycle is generally practiced.
The major item for which reduction of wastewater has been
accomplished has been the use of bag filters for carbon black
recovery instead of wet scrubbers.
Photographic Processing - The major in-plant control practiced
by this industry is metal recovery. Silver can be recovered
by metallic replacement, electrolytic plating, and chemical
precipitation. The use of squeegees for inhibiting carry-over
from one process tank to another reduces the waste load from
the plants. Depleted treatment baths should be discharged
gradually into the sewer in order to minimize treatment plant
upsets.
Hospitals - The most common in-plant controls practiced by
hospitals are the elimination of mercury discharges and the
recovery of silver from spent X-ray developer.
Treatment Technology
The following industries use biological treatment systems:
1) Pharmaceutical Industry
2) Gum and Wood
3) Pesticides
4) Explosives (only in a small number of plants)
5) Photographic processing
6) Hospitals (only a few hospitals treat their own wastes).
8-31-20
-------
Since adhesive and sealant plants mostly discharge to POTW's,
and their wastes are generally weak, only clarification in
lagoons is practiced for BOD removal.
The effluents from thermal black plants in the carbon black
industry are sent to evaporation ponds, thus generating no
discharge.
Table 8-31-7 provides removal efficiencies for biological treat-
ment systems used in the above-mentioned industries.
8-31 -21
-------
TABLE 8-31-7
MISCELLANEOUS CHEMJCALS INDUSTRY
WASTEWATER TREATMENT PRACTICES
Pollutant and Method
Pharmaceuticals
Industry, Removal Efficiency, Percent
Gum and Photographic
Wood Pesticides Explosives Processing Hospital
BOD
Biological
Treatment
70-99
95
No Data
93
30-90
90
oo SOD
i Biological
M Treatment
i
NJ
10
TSS
Biological
Treatment
40-96
75-95
73
50
No Data
No Data
72
88
No Data
No Data
No Data
80-90
-------
AUTO AND OTHER LAUNDRIES
1. General Industry Description
Laundry facilities use a variety of methods to obtain a clean
product. With the exception of dry cleaning plants, the industry
uses substantial quantities of process waters. Presently more than
90% of all laundries discharge to municipal sewer systems and may
account for 5-10% of the average daily flow of sewage. It is also
a significant flow from a quality standpoint,contributing from
10-20 times as much contamination as the average domestic waste.
It is usually strongly alkaline, highly colored, and contains
large quantities of soap or synthetic detergents, soda ash, grease,
dirt and dyes. The BOD is 2-5 times that of domestic sewage.
This industry includes Standard Industrial Classifications
(SIC) 7211, 7213, 7214, 7215, 7216, 7217, 7218, 7219 and 7542.
2. Industrial Categorization
This industry has been divided into the following
subcategories:
Subcategory 1 - Industrial Laundries
Subcategory 2 - Linen Supply
Power Laundries, Family and Commercial
Diaper Service
Subcategory 3 - Auto Wash Establishments
Subcategory 4 - Carpet and Upholstery Cleaning
Subcategory 5 - Coin operated Laundries and Dry Cleaning
Laundry and Garment Service Not Elswhere Classified
Subcategory 6 - Dry Cleaning Plants, Except Rug Cleaning
3. Process Description
Industrial Laundries
Industrial laundries are located in highly populated areas, and
discharge large quantities of high strength wastewater into
municipal treatment facilities. A medium sized industrial
laundry processes between 80,000 - ,100,000 pounds of dry wash
per week. Articles are subjected to a series of wash and rinse
operations to remove oil and grease, and to loosen soil. Some
8-32-1
-------
items are dyed and rinsed. Excess water is extracted and
the items are dried in a dryer. The wastewater has the
appearance of thin oily mud and contains material from
towels used by printers, tool and die makers, filling station
attendants, etc. The soil may be in the form of paints,
varnishes, lacquer, latex rubber, ketone solvents, inks and dyes.
Thus laundry effluent contains products its customers are using
plus laundry agents including alkalies, soaps, detergents,
bleaches, starches, blueing compounds, fabric softeners,
fungicides, petroleum solvents and enzymes.
Linen Supply, Power Laundries (Family and Commercial) and
Diaper Services
This subcategory has the second strongest average waste load.
Operations are similar to industrial laundries, except that
two sudsing stages are used, with a rinse step between them.
In addition, a sour step is utilized in place of the dye step
mentioned above. A sour is an acid chemical added at the end
of the operation to negate the swelling effect of the alkali.
Starch as well as other compounds are added frequently to
linen wash loads. The waste characteristics from this subcategory
are similar to industrial laundries, except that the strength
of the waste is usually lower.
Auto Wash Establishments
Tunnel Type - The vehicle is pulled through a "Tunnel" type
area past different operating stations. The operation is gen-
erally fully automatic, with operations such as interior cleaning,
wiping, and drying performed manually.
Bay Type - In this coin operated type of auto wash,the customer
parks his car in a bay area, and a wand type of water spray
unit is used to soap up and rinse down the vehicle.
Wastes from both type of auto wash systems contain high amounts
of total solids, suspended solids, oil, grease and BOD.
Carpet and Upholstery Cleaning
At present, about 30% of all rug cleaning operations are done
in the home.
In a typical in-plant cleaning operation, the rug is first
beaten to remove dust and dry solids and is then wetted with
water and a mild, dilute detergent. The rug then passes through
a system of either rollers or brushes which work the detergent
into the fiber. A clean wa^er rinse follows, the excess water
is squeezed out and the rug is air dried.
8- 32 2
-------
Upholstery Cleaning is basically a dry process, and therefore,
no wastewater is produced.
Coin Operated Laundries, Dry Cleaning Facilities and
Laundry and Garment Services not Elsewhere Classified
Most coin-operated laundries contain between 25 and 35 machines,
each of which uses 25-30 gallons of water per washing cycle. An
average weekly wastewater volume of 50,000 gallons can be
expected from such an operation. Approximately 100 pounds of
commercial detergent would be used per week. Fifteen cycles
per day is about standard for a washer, but many laundromats
use machines that do 25 cycles or more per day.
Coin-operated dry cleaning is a solvent cleaning process with
no process wastewater discharge.
Laundry and garment services not elsewhere classified include
Chinese and French hand laundries, facilities where clothes
are altered and repaired, and pillow-cleaning operations. Since
their effluent is small in both volume and contaminant levels,
this operation has not been included in this summary.
As a group, the effluent of industries in this subcategory is
weaker than domestic sewage and can, therefore, be handled easily
by municipal treatment plants.
Dry Cleaning Plants, Except Rug Cleaning
A solvent is used to remove the dirt from the fabric and then
the solvent is recovered and recycled by a filter system.
Soil extracted from the cleaned materials should be disposed
of by a scavenger. No wastewaters are usually generated.
4. Wastewater Characterization
Table 8-32-1 contains raw wastewater characteristics for this
industry.
5. Control and Treatment Technology
In-PIant Control - Industrial laundries can reduce the oil
and grease content of wastewater by 80-85% by pretreatment of
laundry using dry cleaning methods before washing.
Thirty percent of the auto laundries recycle wash and/or rinse
water with varying degrees of treatment. Washwater can be
recycled after settling out the solids. Rinse waters have higher
8-32-3
-------
Table 8-32-1
Auto and Other Laundries
Raw Wastewater Characteristics
Waste Parameter (mg/1)
Subcategories
CO
1
W
10
1
4k
BOD
TSS
TDS
COD
pH
Chromium
Copper
Lead
Zinc
Cadmium
Iron
Nickel
Mercury
Oil & Grease
1
Industrial
Laundries
650*-1300*
650 -5000
1500*-6500*
11*-13*
1-4*
0.2-9*
3*-36*
0.5*-9*
0-0.6*
3-125*
1-2.5*
0.001-0.007
400*-3700*
2
Linen Supply
Only
100- 800*
500-1500
1700*-2000
2100*-5100*
10.3*-11.2*
0.06
0.3
0.7*
0.5*
0.04*
2
200*-1200*
3
Auto Washes
Tunnel Type Bay Type
30-80 15- 170
160-230 95- 850
570-1700* 630-2500*
150-275
8.7-9.1
0-1
0-0.3
0-1*
0.3*-0.4*
0-0.04*
3r4
0-0.7
0-0.3 40-200*
4 5
Carpet and Laundromats
Upholstery Cleaning Only
No Data 120-250
15-800
100-2000*
65-1400*
5.1-10*
6
Dry Cleaning
Except Rug Cleaning
No Waste
Note: *See Appendix 5 for parameters which may be
inhibitory to biological systems.
-------
purity requirements and can be treated with a germicide and
de-emulsifier, then clarified and screened prior to recycling.
Treatment Technology - One process that has shown some promise
in the treatment of laundry wastewater is the "Flotation
Diatomaceous Earth (DE) Filter System." In this system the
wastewater is first treated with calcium chloride at a high
pH to break down any emulsions. Air flotation and skimming
then removed the bulk of the oil and grease. The flotation
effluent is then passed through a diatomaceous earth filter
and the scum collected is concentrated by vacuum filtration.
Limited data for removal efficiencies are shown in Table 8-32-2,
8-32 -5
-------
Table 8-32-2
Auto and Other Laundries
Wastewater Treatment Practices
CO
I
U)
Pollutant and Method
BOD
Flotation Diatomaceous Earth Filter
Oxidation - Activated Carbon -
Alum Coagulation - Activated Carbon
Suspended Solids
Flotation Diatomaceous Earth Filter
Oxidation - Activated Carbon
Filtration - Aerobic Digestion
Alum Coagulation - Activated Carbon
Oil and Grease
Flotation Diatomaceous Earth Filter
Filtration - Aerobic Digestion
Flotation - Clarification
Removal Efficiency (Per Cent)
Coin Operated
Industrial Linen Supply Laundromats
125
50-73
88
90
80-99
92
73
87
99
92
84
86
-------
PAINT AND INK
FORMULATION
1- General industry Description
The paint and ink manufacturing industry is essentially a
product formulation industry, in that few, if any, of the raw
materials are manufactured on site. The major products con-
sist of interior and exterior paints, industrial finishes for
such products as automobiles, appliances, furniture; varnish
and lacquer; putty; caulking compounds; sealants; paint and
varnish removers; and printing inks. The principal raw mate-
rials are oils, resins, pigments and solvents.
The majority of plants in this industry discharge to publicly
owned treatment works. Wastewaters are high in BOD, COD,
suspended solids and may contain metals. Establishments
engaged in this industry are included in Standard Industrial
Classifications(SIC) 2851 and 2893.
2. Industrial Categorization
Major Category Subcategory
Paint Oil Base Paint
Water Base Paint
Ink Oil Base Ink
Water Base Ink
3. Process Description
Both paint and ink can be either oil-base or water-base but
there is little difference in the production processes used.
The major production difference is in the carrying agent
oil-base paints and inks are dispersed in an oil mixture,
while water-base paints and inks are dispersed in water with
a biodegradable surfactant used as the dispersing agent.
Another significant difference is in the cleanup procedures.
Since the water-base products contain surfactants, it is much
easier to clean up the tubs with water. The tubs used to
make the oil base products are generally cleaned with an
organic solvent or with a strong caustic solution.
All paints and inks are generally made in batches. The major
difference in the size of a plant is in the size of the
batches. A small plant will make up batches of from 400 to
1,900 liters (100 to 500 gal.) while a large plant will manu-
facture batches of up to 23,000 liters (6,000 gal.). There
are generally too many color formulations to make a continuous
process feasible.
Oil Base Paint and ink
There are three major steps in the oil-base paint and ink
manufacturing process: (1) mixing and grinding of raw mate-
rials, (2) tinting and thinning, and (3) filling operations.
8-33-1
-------
At most plants, the mixing and grinding of raw materials for
oil-base paints and inks are accomplished in one production
step. For high gloss paints, the pigments and a portion of
the binder and vehicle are mixed into a paste of a specified
consistency. This paste is fed to a grinder, which disperses
the pigments by breaking down particle aggregates rather than
by reducing the particle size. Two types of grinders are
ordinarily used for this purpose: pebble or steel ball mills,
or roll-type mills. Other paints are mixed and dispersed in
a mixer using a saw-toothed dispersing blade.
In the next stage of production, the material is transferred
to tinting and thinning tanks, occasionally by means of
portable transfer tanks but more commonly by gravity feed or
pumping. Here, the remaining binder and liquid, as well as
various additives and tinting colors, are incorporated. The
finished product is then transferred to a filling operation
where it is filtered, packaged and labeled.
The product remaining on the sides of the tubs or tanks may
be allowed to drain naturally and the "cleavage," as it is
called, wasted or the sides may be cleaned with a squeegee
during the filling operation until only a small quantity of
product remains. The final cleanup of the tubs generally
consists of flushing with an oil-base solvent until clean.
The dirty solvent is treated in one of three ways: (1) it
is used in the next batch as a part of the formulation;
(2) it is placed in drums that are sold to a company where
it is redistilled and resold; or (3) it is collected in drums
with the cleaner solvent being decanted for subsequent tank
cleaning and returned to the drums until only sludge remains
in the drum. The drum of sludge is then sent to a landfill
for disposal.
Figure 8-33-1 is a flow diagram for oil base paint manufacture.
Water Base Paint and ink
Water-base paints and inks are produced in a slightly different
method than the oil-base products. The pigments and extending
agents are usually received in proper particle size, and the
dispersion of the pigment, surfactant and binder into the
vehicle is accomplished with a saw-toothed disperser. in
small plants the product is thinned and tinted in the same
tub, while in larger plants the product is transferred to
special tanks for final thinning and tinting. Once the formu-
lation is correct the product is transferred to a filling
operation where it is filtered, packaged and labeled in the
same manner as for oil-base paints and inks.
As in the oil-base paint and ink operation, as much product as
possible may be removed from the sides of the tub or tank
before final cleanup starts. Cleanup of the tubs is done
8-33-2
-------
PIGMENTS
OILS
RESINS
TINTS AND
THINNERS
MIXING
TANK
STONE
OR
ROLLER
M ILL
PEBBLE
OR
BALL M ILL
DISPERSING
TANK
THINNING
AND
TINTING
TANK
FILLING
PACKAGING
AND
SHIPM ENT
Figure 8-33-1
Paint and ink industry
Flow Diagram of Manufacturing Process for Oil-Base Paints
8-33-3
-------
simply by washing the sides with a graden hose or a more
sophisticated washing device. The washwater may be:
(1) collected in holding tanks and treated before discharge;
(2) collected in drums and taken to a landill; (3) discharged
directly to a sewer or receiving stream; (4) reused in the
next batch; or (5) reused in the washing operation.
Allied products manufactured by the paint portion of the
industry include putty, caulking compounds, paint and varnish
removers, shellacs, stains, wood fillers and wood sealers.
The manufacturing process for these products does not gen-
erally utilize water, except for some water-base stains and
paint removers. The types of wastes generated in cleanup of
equipment do not greatly differ from those generated in
paint formulation. As these categories are generally low in
water use and are very similar to paints, they have been con-
sidered as being in the same category.
4. wastewater Characterization
Table 8-33-1 shows raw wasteload data for process water only.
The process with the largest water usage is non-contact
cooling water, which can account for up to 80% of the waste-
water discharge. This should not be contaminated when
operated properly. Wastewaters from cleanup operations, air
pollution control equipment, and sanitary discharges account
for a major portion of the remaining discharge flow.
5. Control and Treatment Technology
In-Plant Control - The use of modified washing methods, such
as the use of high pressure nozzles, can reduce the amount
of water discharged.
Another method for reducing wastewater is by reusing washwater,
if the formulation of the next batch is compatible.
A third method of reducing wastewater is the use of dry clean-
ing procedures for handling spills and leaks.
Treatment Technology - The most common treatment schemes con-
sist of either batch or continuous clarification basins or
tanks with pH adjustment and coagulant feeds. in addition,
many plants send their process wastes to scavengers for dis-
posal, which totally eliminates wastewater discharge.
8-33 -4
-------
TABLE 8-J3-1
Raw Waste Characteristics
Paint and ink Industry
Parameter mg/1
BOD
TSS
COD
PH
Iron
Lead
Manganese
Zinc
Oil and Grease
Kjeldahl Nitrogen
Paint
60-1800*
40-11000
*
5000-8000*
3.4-13.2*
4-40*
1*-10*
0-10
0.3-10*
4-1000*
0-200
Subcategories
ink
60-2000*
15-1200
200-3000*
5.6-11.6*
0.6-2.2
0.3
0-0.1
No Data
7-200*
No Data
* See Appendix 5 for parameters which may be inhibitory to
biological systems.
8-33-5
-------
STEAM SUPPLY AND
NONCONTACT COOLING
1. General Industry Description
The Steam Supply and Noncontact Cooling Water industry includes
all establishments engaged in the production or distribution
of steam and heated or cool air/and the use of noncontact
cooling water for steam supply and any other use. Steam is
generally used for power generation, space heating, and process
heating. Noncontact cooling water in other than power generating
plants is used for product, process, equipment cooling and air
conditioning. Wastes from the steam supply industry contain widely
varying pH values, metals, corrosion inhibitors and dissolved and
suspended solids. Noncontact cooling water waste streams contain
corrosion inhibitors, slime inhibitors and dissolved and suspended
solids. The Steam Supply portion of this industry is covered
by Standard Industrial Classification (SIC) 4961. The Non-
contact Cooling Water portion does not have a SIC classification.
Subcategory
Continuous Wastewater Discharges
Intermittent Wastewater Discharges
Thermal Discharges
Chemical Discharges
2. Industrial Categorization
Major Category
Steam Supply
Noncontact Cooling Water
3. Process Description
Steam Supply
Water and heat are
-------
Wastewaters are discharged both continually and intermittently
from a number of sources in the operation. Since steam may be
lost in the cycle, make-up water which may require pretreat-
ment is added to make it acceptable to the boiler. The higher
the pressure and temperature of the boiler, the more stringent
the make-up water quality requirements are. Water treatment
consists of filtration, softening, and/or dissolved solids
removal by ion exchange. Waste streams from the water treat-
ment processes consist of filter backwashes, sludges from
clarifiers, and brines from ion exchange regeneration. These
wastes are generally intermittent.
Due to the continued evaporation of water within the boiler,
buildup of dissolved solids occurs. To maintain total dissolved
solids within allowable limits, a controlled amount of boiler
water is blown down. The blowdown is usually continuous from
the steam drum while blowdown from the mud drum is intermittent.
Water used for steam generation is normally internally treated
with chemicals to:
1) Prevent scale formation caused by hardness.
2) Provide pH control and oxygen scavenging to prevent corrosion.
3) Condition any sludge that may form.
The chemicals used for these purposes are di- or tri-sodium
phosphate, ammonia, caustic, cyclohexylamine, sodium sulfite,
hydrazine, and morpholine. The particular chemicals used
appear in the boiler blowdown. In spite of internal water
treatment, deposits accumulate in boiler tubes which, if
allowed to go unchecked, would cause overheating and tube
failure. To prevent this, boiler tubes are cleaned. The interval
between cleanings normally varies from once a year to once in
ten years. Scale deposits may include calcium, magnesium,
phosphates, oxides of iron and copper, and, to a lesser extent,
zinc, nickel, and aluminum. Common cleaning agents used are
hydrochloric acid, citric acid, formic and hydroxyacetic acid,
or solutions containing such chemicals as chelates, potassium
bromate, phosphates, thiourea, ammonia, hydrazine, and caustic
soda. The water containing the scaling materials and the
particular chemical or chemicals used, constitute a waste
stream.
8-34-2
-------
The fireside of the boiler is also cleaned approximately once
per year. The fireside is usually cleaned only with water,
and the waste stream contains the slag buildup caused by the
fuel gases.
Steam generation plants which utilize coal or oil or waste as
fuel produce ash as a waste product of combustion. The ash
can be bottom and/or fly ash. Bottom ash (from coal only)
accumulates in the furnace bottom, while fly ash (from coal and
oil) is carried over in the flue gas stream. Ash is handled
either dry (pneumatic) or wet (sluicing). Wet handling of ash
produces wastewaters. The storage of coal can produce a
waste stream caused by rain runoff.
Noncontact Cooling Water
Noncontact cooling waters are used to accept heat from a process
which requires cooling. Once through noncontact cooling systems
result in both chemical and thermal waste discharges, while
recirculating systems generate only chemical waste discharges.
In once through noncontact cooling systems, it is necessary
to prevent growth of organisms in condenser tubes in order to
maintain heat transfer surfaces in clean condition. This is
normally accomplished by adding slug quantities of common
biocides, such as chlorine or hypochlorites. These chemicals
appear in the cooling water discharge stream, in addition to
heat.
In a closed cycle cooling system where a cooling tower is used
to dissipate the heat to the environment, the only waste
stream generated is cooling tower blowdown, which contains
dissolved solids and chemicals added to prevent scale
buildup and slime growth. These chemicals include chlorine,
hypochlorite, and compounds of chromium, zinc, and phosphate.
4. Wastewater Characterization
Table 8-34-1 contains the wastewater characteristics for the
processes described above.
8-34-3
-------
Waste Parameter
(mg/I)
TABLE 8-34-1
STEAM SUPPLY AND NONCONTACT COOLING WATER INDUSTRIES
RAW WASTEWATER CHARACTERISTICS
Process Wastes
Flow, GPD
Flow Type
TSS
TDS
COD
? pH
Ul
J^ Chromates
1
fe Total Nitrogen
Phosphate as P
Iron
Copper
Nickel
Zinc
Oil and Grease
Chlorine, Free
Available
Notes:
M
MM
*
B
C
Boiler
Steam Drum
Slowdown
1.4M-216M
C
0-600
100-10M*
10-1. 4M*
7-11*
0-7*
0-25
0-80
0-80*
0-2*
0-1.2
Present
Boiler
Mud Drum
Slowdown
B
lM*-2m*
60-1M*
7-11*
3-10
0-20
0.3-4
0.03-4*
0.1
0.05-0.5*
Present
= 1,000
= 1,000,000
See Appendix 5 for parameters
Batch Process
Continuous Process
Ash Pond
Overflow
C
700
500
No Data
No Data
0
2
1.3
12*
0.2
0.3
0.5*
Present
which may be
Chemical
Cleanings
of Boilers
B
150-2. 5M
No Data
20-3M*
low & high
0-12*
No Data
0-4
2-1M*
0-200*
5*-75*
5*-50*
Present
inhibitory to
Coal
Storage
Runoff
B
350
3500*
No Data
3
No Data
No Data
No Data
0.5
2*
1.5*
Present
biological
Once Through
Cooling Water
Discharge
C
No Data
No Data
No Data
No Data
No Data
No Data
No Data
No Data
No Data
No Data
No Data
No Data
Present
systems
Cooling
Tower
Blowdown
3-300
C and B
No Data
No Data
No Data
No Data
0-30*
No Data
0-30
No Data
No Data
No Data
0-15*
No Data
1
-------
5. Control and Treatment Technology
In-Plant Control
Control technology to minimize wastewater discharges may
involve process equipment changes. Equipment to improve the
quality of the water to the steam boiler would reduce the
boiler blowdown volume. Substitution of closed cycle cooling
(cooling towers) for once through cooling systems can
eliminate thermal discharges.
Treatment Technology
Metals can be removed from wastewaters by pH adjustment with
lime to 8.5-9.5 which results in precipitation of the metal
hydroxides. The precipitated metal hydroxides and the suspended
solids can then be removed in a clarifier. Biocides can be
eliminated by the addition of a reducing agent, such as sulfites,
which reduce chlorine to chlorides.
8-34-5
-------
INDEX
Industry Section
Asbestos 23
Auto and Other Laundries 32
Cement 7
Chemicals
Inorganic 11
Organic 10
Phosphates 18
Miscellaneous 31
Adhesive and Sealants
Carbon Black
Explosives
Gum and Wood Chemicals
Hospitals
Pesticides and Agricultural Chemicals
Pharmaceuticals
Photographic Processing
Dairy Products 1
Feed Lots 8
Fertilizer 14
Food
Canned and Preserved Fruits and Vegetables 3
Canned and Preserved Seafood 4
Grain Mills 2
Meat Products 28
Miscellaneous 30
Bakery and Confectionary Products
Beverages, Alcoholic and Non-alcoholic
Pet Foods
Vegetable Oil Processing and Refining
Miscellaneous and Specialty Products
Sugar 5
Glass 22
Leather 21
-------
INDEX (continued)
Metals
Ferro Alloys 20
Iron and Steel 16
Metal Finishing and Electroplating 9
Non Ferrous Metals 17
Paint and Ink 33
Paper
Builders Paper and Roofing Felt 27
Pulp, Paper and Paperboard 26
Petroleum 15
Plastics and Synthetic Materials 12
Rubber 24
Soap and Detergents 13
Steam Electric Power Plants 19
Steam Supply and Noncontact Cooling 34
Textiles 6
Timber 25
Water Supply 29
-------
LIST OF REFERENCES
Industry
Dairy Products
Grain Mills
Canned and
Preserved
Fruits and
Vegetables
Canned and
Preserved
Seafood
Sugar
Development Document Title
Dairy Product Processing
1. Grain Processing Segment
2. Animal Feed, Breakfast
Cereal and Wheat Starch
Segment
1. Apple,Citrus and Potato
Segment
2. Canned and Preserved
Fruits and Vegetables
1. Catfish, Crab, Shrimp
and Tuna Segment
2. Fishmeal, Salmon, Bottom
Fish, Sardine, Herring,
Clam, Oyster, Scallop and
Abalone Segment
1. Beet Sugar Processing
Subcategory
2. Cane Sugar Refining
Segment
Document Number
440/1-74-021-a
440/1-74-028-a
440/1-74/039
440/1-74-027-a
Contractors Draft
(contract #68-01-2291)
440/1-74-020-a
440/1-74/041
440/1-74-002-b
440/1-74-002-c
Textiles
Cement
Feedlots
Metal Finishing
and Electro-
plating
Organic
Chemicals
Inorganic
Chemicals
Textile Mills
Cement Manufacturing
Feedlots
1. Cooper, Nickel, Chromium
and Zinc Segment
2. Electroplating
3. Metal Finishing
1. Major Organic Products
Segment
2. Significant Organic Pro-
ducts Segment
1. Major Inorganic Products
Segment
2. Significant Inorganic Pro-
ducts Segment
440/1-74-022-a
440/1-74-005-a
440/1-74-004-a
440/1-74-003-a
440/1-75-040
440/1-75/070-a
440/1-74-009-a
440/1-75/045
440/1-74-007-a
440/1-75-037
-------
LIST OF REFERENCES (continued)
Plastics and
Synthetic
Materials
Soap and
Detergents
Fertilizer
Petroleum
Iron and Steel
1. Synthetic Resins Segment
2. Synthetic Polymens Segment
440/1-74-010-a
440/1-74/036
Non Ferrous
Metals
Phosphates
Steam Electric
Power Plants
Ferroalloys
Leather
Glass
Asbestos
Soap and Detergent Manufacturing 440/1-74-018-a
1. Basic Fertilizer Chemicals
2. Formulated Fertilizer
Segment
Petroleum Refining
1. Steel Making
2. Hot Forming and Cold
Finishing Segment Plus
Addendum
1. Bauxite Refining Subcategory
2. Primary Aluminum Smelting
3. Secondary Aluminum Smelting
4. Primary Copper Smelting
and Primary Cooper Refining
5. Secondary Copper
6. Lead
7. Zinc
1. Phosphorous Derived
Chemicals
2. Other Non-Fertilizer
Phosphate Chemicals
Steam Electric Power
Generating
1. Smelting and Slag Processing
2. Calcium Carbide
3. Electrolytic Ferroalloys
440/1-74-011-a
440/1-74-042
440/1-74-014-a
440/1-74-024-a
Contractors Draft
(Contract #68-01-1507)
440/1-74-019-c
440/1-74-019-d
440/1-74-019-e
440/1-75-032-b
440/1-75-032-c
440/1-75-032-a
440/1-75-032
440/1-74-006-a
440/1-75-043
440/1-73-029
440/1-74-008-a
440/1-75-038
440/1-75-038-a
Leather Tanning and Finishing 440/1-74-016-a
1. Insulation Fiberglass
2. Flat Glass
3. Pressed and Blown Glass
1. Building, Construction and
Paper Segment
2. Textile, Friction Materials
and Sealing Devices
440/1-74-001-b
440/1-74-001-c
440/1-74/034
440/1-74-017-a
440/1-74-035
-------
LIST OF REFERENCES (continued)
Rubber
Timber
Pulp, Paper
and Paperboard
Builders Paper
and Roofing
Felt
Meat Products
Paint and Ink
1. Tire and Synthetic Segment
2. Fabricated and Recalimed
Rubber
1. Plywood, Hardboard and Wood
Preserving Segment
2. Wet Storage, Sawmills, Par-
ticleboard and Insulation
Board
3. Furniture Manufacturing
1. Unbleached Kraft and Semi-
chemical Pulp Segment
2. Pulp, Paper and Paperboard
Industry
440/1-74-013-a
440/1-74-030
440/1-74-023-a
440/1-74-033
Contractor's Draft
440/l-74-025a
Contractor's Draft
(Contract #68-01-1514)
Builders Paper and Roofing Felt 440/1-74-026-a
1. Red Meat Processing Segment
2. Renderer Segment
3. Processer Segment
Auto and Other
Laundries
Water Supply
Steam Supply
and Non Contact
Cooling
Paint Formulating and Ink
Formulating
Auto and Other Laundries
Water Supply
Steam Supply
Miscellaneous Miscellaneous Foods
and Beverages and Beverages
Miscellaneous
Chemicals
Miscellaneous Chemicals
440/1-74-012-a
440/1-74-031-a
440/1-74-031
440/1-75-050
EPA Draft
Contractor's Draft
Contractor's Draft
Contractor's Draft
Contractor's Draft
------- |