an industrial Waste Guide to the
Meat
I ndustry
U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service
-------
Dedication
This guide is dedicated to the memory of
A. Stanford Jolmson, general project engi-
neer, Oscar Mayer & Co., who devoted many
hours to its preparation.
Mr. Johnson was an instructor and re-
search fellow in the Civil Engineering De-
partment, University of Minnesota prior to
his association with Oscar Mayer & Co. In
1956, while working toward his M.S.C.E. at
Minnesota, he was a joint winner of the Har-
rison Prescott Eddy Medal for noteworthy
research. The research involved study of
various aspects of the anaerobic contact
process for treatment of meat plant wastes.
This work led to the adoption of this method
of treatment first at Albert Lea, Minn., and
later at Austin, Minn., and Momence, 111.
Mr. Johnson was active in the National
Technical Task Committee on Industrial
Wastes; the American Meat Institute Sani-
tation and Waste Treatment Committee;
American Waterworks Association; Central
States Water Pollution Control Association;
Water Pollution Control Federation, and the
Institute of Sanitation Management.
A. Stanford Jolmson was an excellent en-
gineer. He imderstood the relationship of
scientific investigation to engineering and as
the result of this understanding his company
and the meat industry made significant prog-
ress in the field of waste treatment.
-------
an Industrial Waste Guide to the
Meat
Industry
Prepared by the
Committee on Sanitation and Waste Treatment
of the American Meat Institute
in cooperation with the National Technical
Task Committee on Industrial Wastes
U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
PUBLIC HEALTH SERVICE
Division of Water Supply and Pollution Control
Washington, D.C. 20201
-------
Other publications in the Industrial Waste Guide Series
PHS Pub. No. 991: Poultry Processing Industry (in press)
PHS Pub. No. 9521 Fruit Processing Industry
PHS Pub. No. 7561 Potato Chip Industry
PHS Pub, No. 691 s Cane Sugar Industry
PHS Pub. No. 677: Cotton Textile Industry
PHS Pub. No. 5091 Commercial Laundering Industry
PHS Pub. No. 4381 Wool Processing Industry
PHS Pub. No. 298 s Milk Processing Industry
Public Health Service Publication No. 386
Revised 1965
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C., 20402 - Price 20 cents
-------
Preface
In the meat industry, as in many others,
control and disposal of wastes is a major con-
cern of many plants. Optimum utilization
and reduction of wastes is essential for the
most economical production in small as well
as large plants. Wastes which cannot be
eliminated must be disposed of in suitable
manner. Protecting the Nation's limited
water resources for maximum use is mutually
beneficial to industry, other special groups,
individual citizens, and the Nation as a whole.
In recognition of this, industries are paying
increasing attention to the disposal of their
wastes in a manner which will not impair the
utility of stream waters for other beneficial
uses.
The original Guide was prepared by the
U.S. Public Health Service and published in
supplement D of the report entitled "Ohio
River Pollution Control" in 1943.
In 1954 the Committee on Meat Packing
Plant Waste Disposal of the American Meat
Institute suggested some changes which were
incorporated in a revised issue of the Guide
to bring it up to date. Further revisions of
the Guide were prepared by the Committee
on Sanitation and Waste Treatment in 1964
to include information on primary treatment,
the anaerobic contact process and anaerobic-
aerobic ponds. These changes were sub-
mitted to the Public Health Service through
the meat industry representative on the
National Technical Task Committee on In-
dustrial Wastes and are incorporated herein.
The National Technical Task Committee
is composed of representatives from the
Nation's leading industries concerned with
solving difficult industrial waste problems.
The objective of the organization is to perform
technical tasks pertaining to industrial wastes
in cooperation with the Public Health Service
and all others concerned with improving the
quality of our water resources. The prepa-
ration of this revision was one of the tasks
assumed by the meat industry in carrying out
this objective.
HI
-------
CONTENTS
Page
INTRODUCTION 1
DESCRIPTION OF PROCESS 1
RAW MATERIALS AND PRODUCTS 2
ORIGIN OF WASTEWATER 2
Slaughterhouses 2
Packing Plants 3
Stockyards 4
Processing Plants 4
COMBINED WASTEWATER FLOW AND CHARACTERISTICS 5
POLLUTION EFFECTS 6
REMEDIAL MEASURES 6
Plant Practices 6
Treatment 8
Primary 8
Secondary 8
Trickling Filters 8
Irrigation 8
Anaerobic Contact 9
Stabilization Ponds 10
BIBLIOGRAPHY 13
v
-------
OXIDATION
PONDS
MAIN CONTROL
BLDG.
DEGASIFIERS
EQUALIZER
SLUDGE
SEPARATORS
SLUDGE
LAGOONS
Full scale anaerobic contact waste treatment plant, Wilson & Co., Inc., Albert Lea, Minnesota, U.S.A.
Vl
-------
Introduction
This publication represents the efforts of
waste technologists of the meat industry and
others to develop a concise practical Guide
for operating and design personnel. Reduc-
tion of wastes at their source is the initial
objective of control measures. Appreciable
reduction of waste can be accomplished
through waste prevention measures carried
out within the meat processing plant.
The section on treatment is not intended
to be a comprehensive discussion of meat
processing waste treatment. Sufficient infor-
mation on waste treatment is included to
suggest possible methods of solution to stream
pollution problems which cannot be eliminated
or adequately corrected by waste prevention
procedures. Some performance data are pre-
sented on the more usual as well as the more
recently developed meat processing waste
treatment processes. This section will also
serve to emphasize to meat plant supervisory
personnel the value of waste saving methods
in reducing total waste treatment costs.
The wastes from stockyards, slaughter-
houses, and packinghouses are similar chem-
ically to domestic sewage but are considerably
more concentrated. The principal deleteri-
ous effect of these wastes on streams and other
bodies of water is their deoxygenating effect.
Stockyard wastes contain animal excreta,
and the amount and strength of the waste
varies considerably, depending upon whether
the pens are covered, the presence or absence
of catch basins, practice in manure removal,
frequency of washing, etc.
Slaughterhouses are establishments for the
killing and dressing of meat. Little process-
ing of the meat or of byproducts is done.
Most slaughterhouses are relatively small,
although some may kill several hundred
animals per day.
Packinghouses are equipped to process
the meat and byproducts to a much greater
extent. The amount of processing varies
considerably from plant to plant, resulting
in wide variations in volume, strength, and
chemical characteristics of effluent discharged
to the sewers.
Description of Process
8i«Hfkterk»u«
The slaughterhouse or abattoir is principally a
killing and dressing establishment doing little proc-
essing of byproducts. Its finished product is the
fresh carcass, plus a few fresh meat byproducts such
as hearts, livers, and tongues. Briefly, the process
consists of stunning, sticking, and bleeding animals
on the killing floor. Carcasses are trimmed, wished,
and hung in cooling roomB. Livers, hearts, and
kidneyB are sent to the cooling rooms to be chilled
before being marketed. Hides, skins, and pelts are
removed from the cattle, calves, and sheep and are
salted and piled until shipped to tanners or wool
1
-------
processing plants. Viscera are removed and sent to
rendering plants, along with feet and head bones.
The feet and head bones may also be sent to glue-
works. Many slaughterhouses are now equipped to
do their own rendering of inedible offal into tallow,
grease, tankage, and meat scraps.
Packinghouse
Packinghouse killing floor operations are, in
general, carried out with more attention to recovery
of salable products. Carcasses are trimmed, cleaned,
and cooled much the same as in the slaughterhouse,
except that the packinghouse further processes some
of the meat by cooking, curing, smoking, and pick-
ling. Some of the operations conducted, in addition
to those concerning processing of meat cuts, are:
manufacture of sausage and canning of meat; render-
ing of edible fats into lard and edible tallow; the
cleaning of casings; the drying of hog hair; and the
rendering of inedible fata into greases and inedible
tallows.
The packinghouse is also equipped to process in
varying degrees the "byproducts" which a slaughter-
house ships out as raw byproducts. Blood is col-
lected and dried for edible and inedible uses. Tan-
ning, wool pulling, and manufacture of glues, soaps,
and fertilizers are, in general, carried on by separate
plants.
Processing Plant
Processing plant operations include manufacture
of smoked meats and sausage and canning of meat
products. The raw materials are purchased from
slaughterhouses or packinghouses in the form of
carcasses, various meat cuts, and trimmings.
Raw Materials and Products
The average weight of animals slaughtered com-
mercially in the United States in 1962, according to
the Bureau of Agricultural Economics, U.S. Depart-
ment of Agriculture is as follows:
Animal
Weight
Dressed
on hoof
weight1
Pounds
Pounds
Cattle
1, 005
574
Calves
223
2 125
Hogs
239
* 142
Sheep
97
47
1 Not Including edible organs.
»Hide off.
i Excluding lard.
The chief product, the carcass, is marketed in
various cuts of fresh, smoked, cured, pickled, and
canned meats, the slaughterhouse confining its pro-
duction to fresh meats while the packer produces the
full line of processed meats.
Byproducts of the slaughterhouse generally con-
sist of cured hides, skins, and pelts, inedible tallows,
animal feeds, and miscellaneous fresh offal (collected
by specialty houses).
Packinghouse byproducts are very numerous.
Some of the principal byproducts are as follows
(products or uses shown in parentheses are not
necessarily processed at the packinghouse):
(a) Edible fats.—Oleo stock, oil, and stearine;
edible tallow; lard.
(b) Inedible fats.—Tallow; grease; neat's-foot
stock.
(c) Hides, skins, pelts (pulled wool).
(d) Tankage, meat scraps, and stick (evaporated
tank water).
(e) Dried blood.—(blood albumin).
if) Bone and bone products.—Steamed bone meal;
cooked bone meal; dry bone.
(g) Hog hair and bristles.
{h) Horns and hoofs.
(i) Intestines.—Sausage casings, chitterlings.
(j) Glands.
Origin of Wastewater
SLAUGHTERHOUSES Some small houses use part of the blood to add to
Killing floor.—Many houses save blood for sale to their tankage and sell or give away the remainder,
rendering plants or to fertilizer manufacturers. This decreases substantially the oxygen demand
-------
and the color of the effluent discharged to the sewer.
Paunch manure is usually segregated from the
liquid wastes and disposed of separately. At
some of the rural plants, it is hauled away by farm-
ers for soil conditioning, A number of the city
slaughterhouses dispose of paunch manure with
garbage. The separate disposal of paunch manure
reduces materially the settleable solids in the
effluent entering the sewers.
Floor washes contain blood, manure, flesh, and fat
particles.
Carcass dressing.—Carcass washes contain blood,
flesh, and fat particles from trimming.
Rendering.—Many slaughterhouses render offal
for inedible tallows and tankage. Where wet
rendering is practiced, tank water remaining after
grease and residue are taken off, is further processed.
Processing of tank water reduces substantially the
biochemical oxygen demand and the solids content of
effluent discharged to the sewer. Larger plants
evaporate this tank water to produce a thick resi-
due, called "stick," which is mixed with the tankage.
Nearly all the smaller plants have installations of
dry rendering and produce no tank water because
any water charged into the melter is evaporated.
Inedible raw material is prepared for rendering by
hashing and washing. This operation adds a con-
siderable quantity of residue to the effluent. This
residue consists of small flesh and fat particles and
intestinal contents. Where the steam rendering
process is used, the pressing of the residue into
cakes or centrifuging produces additional tank
water. This liquor is usually added to the stick
evaporator feed.
Wash waters, both floor and equipment, from
rendering operations contribute varying amounts of
pollutional material, depending on the care exer-
cised in handling materials and on general cleanliness.
Hide cellar.—Green hides are chuted to the cellar
from the killing floor. Here they are piled flesh-
side up and sprinkled with salt. A small amount of
drainage from these piles, in addition to floor wash,
goes to the sewer.
Hog hair removal.—Hair is loosened in a scalding
tub or vat and removed by scraping. Discharge of
vat waters and scrapings contribute hair, dirt, and
scurf from the hog skin.
Cooling room.—Liquid wastes draining from this
unit are of minor significance. Some houses use
sawdust on the floor, which is swept up periodically.
These sweepings may be burned, buried or dis-
posed of in other sanitary manner.
765-014 O—88 2
PACKING PLANTS
Carcass dressing.—This operation is, in general,
similar to that carried on in the slaughterhouse.
Wash wastes are discharged into catch basins, and
the grease is recovered.
Rendering.—The larger packinghouses do both
edible and inedible rendering using various pro-
cesses, including steam and dry rendering and low
temperature rendering. Fats are hashed and washed
prior to being discharged into the rendering vessels,
and the wash water is discharged to lines running
to a catch basin where the fats are recovered and
the heavier materials are separated from the effluent.
The condensate from the steam rendering produces
a liquor containing various nitrogenous extracts.
This liquor may be discharged to the sewers, but
it is usually concentrated into what is called "stick",
and the stick is mixed and dried with tankage.
The residue from steam rendering is centrifuged
for recovery of grease and solids. The liquors
coming from the centrifuge are mixed with the
tank water for conversion into stick. The bones
from cattle feet are rendered in hot water to recover
neat's-foot stock. The water in which the bones
are cooked has some pollutional characteristics.
Hide cellar.—The wastes from the hide cellar are
similar to those from a slaughterhouse but are
extremely small in quantity, though high in salt
content.
Hog hair removal.—In the larger plants hair
removal is accomplished by a mechanical scraper.
The hair is removed, washed, and sold unprocessed,
or further processed by boiling in water for 8 to
10 hours with a small amount of caustic soda.
The hair is removed from the cooking tank and run
through pickers for breaking up the tufts of hair.
It is then dried and baled for sale. The scalding
vat, wash, and cook waters containing dirt, scurf,
and escaped hair are discharged. Some of the
smaller packing plants do not produce enough
hair to justify its recovery, but dispose of it with
other solid refuse.
Hair may also be hydrolyzed by steam rendering
with the addition of lime. The rendered product
is then dried to produce a powdered material.
Casing cleaning.—Casings are washed, cleaned
of their contents and mucosa by squeezing or
pressing, salted, drained, resalted, and packed
for shipment. Trimmings and mucosa from the
casings are rendered to recover grease and protein.
The waste waters from the cleaning machines are
discharged to catch basins for grease recovery.
3
-------
Tripe room.—The tripe, or muscular part of the
stomachs of cattle, is washed and scalded. The
wash and scalding waters containing grease and
suspended matter are discharged into catch basins.
Tripe may also be produced from hog stomachs.
Sausage room.—Process consists of preparing
fillings from meat and stuffing the casings. Utensil
and floor washes are discharged.
Laundry.—The laundries of the large plants are of
considerable size. An analysis of this waste is
included with the tabulation of analyses of hog plant
wastes in table 1.
Glue stocks.—The manufacture of glue is usually
carried out in a separate plant. Glue is a collage-
nous matter extracted from heads, feet, bones,
tendons, and hide trimmings by rendering them in
water at different temperatures. The waste consists
of wash waters used to wash the raw materials prior
to extraction.
Soap.—The manufacture of soaps is confined to
some of the largest houses. The average packing-
house produces the inedible tallow and grease sold
to the soap manufacturers. The wastes produced
from the manufacture of such greases are covered
under rendering.
Fertilizers.—The production of fertilizers has lost
some of its importance in the packinghouse with the
advent of dry rendering which enables production
of higher grade tankages which are used more for
stock feed than for fertilizer. The fertilizer industry,
once largely a packinghouse operation, has become
more the province of the chemical industry, and
packinghouse fertilizer stocks are shipped for use by
fertilizer plants.
The character of the major components of the
waste of a hog packinghouse is indicated in table 1.
STOCKYAIIDS
Stockyards appurtenant to slaughter and packing
plants are ordinarily provided with catch basins and
are usually floored and sometimes covered.
Wastes consist of water trough overflow, liquid
excreta, and pen wash waters containing manure.
Uncovered pens are subject to flushing in rainy
weather with consequent leachings from manure and
carrying over of manure itself to the sewer.
The character of these wastes would be expected
to vary widely, dependent on the presence or absence
of catch basins, practice in manure removal, fre-
quency of washing, etc.
PROCESSING PLANTS
The principal sources of waste occur in the
processing of sausages and smoked meats. Bones,
floor scraps, and other inedible trimmings are sold
to renderers. Little or no wastewater originates in
many of the processing operations. Principal sources
during production are water used in cooking or
chilling the product. The cleanup water following
production contains meat and fat particles and the
quantity approximates that used in processing.
Table 1.—Analyses of major components of waste from hog packinghouse 1
Concentration (parts per million)
Killing department.-
Blood ancf tank water
Scalding tub
Hog dehairing
Hair cook water
Hair wash water..
Meat cutting
Gut washer
Curing room
Curing room showers
Cured meat wash
Pickle
Sausage and miscellaneous.
Lard department
Byproducts..
Laundry
Stockyards J
Solids
Total
1,840
44, 640
13, 560
1, 540
4, 680
7, 680
2, 840
22, 600
26, 480
34, 100
9, 560
140, 000
11, 380
820
4, 000
18, 620
Sus-
pended
220
3, 690
8, 360
560
80
6, 780
610
15, 120
1, 800
1, 720
920
560
180
1, 380
4, 120
173
Nitrogen
Organic
134
5, 400
1, 290
158
586
822
33
643
83
255
109
2, 750
136
84
186
56
11
NH»
6
205
40
10
30
18
2. 5
43
12
25
17. 5
37
4
25
50
5
8
CI as
NaCl
5-day bio-
chemical
oxygen
demand
435
6, 670
640
290
290
230
1,620
360
19, 700
29, 600
6, 200
77, 800
880
230
1, 330
825
32, 000
4, 600
650
3, 400
2, 200
520
13, 200
2, 040
460
1, 960
18, 000
800
180
2, 200
1, 300
64
i Iowa Engineering Experiment Station Bulletin No. 130.
4
> From supplement D, Industrial Waste Guides, U.S. Public Health
Service, 1943.
-------
Combined Wastewater Flow and Characteristics
Quantity and characteristics of the combined
wastewater from the meat industry are subject to
variation depending upon the species of animals
slaughtered, rendering practices, segregation of clear
water, and the amount of processing carried out in
the plant. Table 2 lists the losses from packing-
houses per thousand pounds of live weight slaugh-
tered, as reported by Mohhnan in 1949. Similar
data for nine packinghouses and three slaughter-
houses are shown in table 3. Table 4 lists typical
values for flow and characteristics based on present
practice.
Table 2.—Unit packinghouse losses 1
[Pounds per 1,000 pounds of live weight]
Type
BOD
Suspended
Nitrogen
Grease
solids
18. 0
12. 0
2. 67
0. 90
Do
15. 0
9. 1
1. 29
2. 30
Mixed ..
12. 7
4. 6
2. 02
1. 44
Hogs - —
13. 1
9. 8
1. 25
2. 83
Cattle —
20. 8
14. 8
2. 24
. 68
Do..
15. 7
14. 8
2. 01
1. 79
Do
10. 5
10. 0
1. 02
1. 00
Mixed -
19. 7
9. 4
2. 59
. 60
9. 8
7. 2
1. 46
. 27
Mixed — —
16. 7
15. 0
2. 18
2. 00
Cattle - .. .
10. 0
11. 0
1. 08
. 55
Mixed . —
14. 7
13. 2
1. 70
1. 5
Do
6. 5
6. 2
. 79
. 5
Do
19. 2
11. 2
2. 10
2. 1
Do - -
8. 9
10. 8
. 89
Do
21. 6
21. 7
1. 82
6. 0
Average -
14, 6
12. 0
1. 70
1. 63
1 Adapted from a presentation by F, W. Mohlman at the Conference on Research of the American Meat Institute, 1949.
Table 3.— Variation in unit losses between packinghouses 1
[Per 1,000 pounds of live weight]
Plant
Gallons of
waste
Pounds of
BOD
Pounds of
suspended
solids
Pounds of
organic and
ammonia
nitrogen
Years of
data
A
1,300
1,400
2, 300
3, 250
1,300
4, 350
1, 370
750
1, 100
1,250
1, 080
1, 800
12. 7
19. 7
16. 7
14. 7
6. 5
19. 7
8. 0
16. 0
10. 7
23. 5
11. 8
20. 0
4. 6
9. 4
14 9
13. 2
6. 3
22. 1
10. 4
20. 0
9. 1
16. 2
12. 0
11. 0
2. 0
2. 6
2. 2
1. 7
. 8
2. 1
1. 0
B . -
C
D
E
F. ..
G
H,
1937
1949
1934
1950
Hj_
1. 2
i,s
i.
1. 6
A
'Adapted from a presentation by Hill at the American Meat Institute's
annual meeting In October 1980,
»Slaughtering only.
5
-------
Table 4,—Approximate range of flows, analyses, and waste loadings for slaughterhouses, packinghouses, and processing
plants 1
Operation
Waste flow
gallons per
1,000 pound
live weight
slaughtered
Typical analysis, mg/liter
Waste loading, pounds per 1,000
pound live weight slaughtered
Biochemical
oxygen
demand
Suspended
solids
Grease
Biochemical
oxygen
demand
Suspended
solids
Grease
Slaughterhouse
Packinghouse - -
Processing plant
500-2, 000
750-3, 500
2 1, 000-4, 000
2, 200-650
3, 000-400
800-200
3, 000-930
2, 000-230
800-200
1, 000-200
1, 000-200
300-100
9. 2-10. 8
18. 7-11, 7
s 6. 7
12. 5-15. 4
12. 5- 6. 7
2 6. 7
4. 2-3. 3
6. 3-5. 8
2 2. 5-3. 3
' Table prepared from data from various sources Including technical 2 Pounds per 1,000 pound finished product,
literature and private correspondence.
Pollution Effects
Meat plant wastes are quite similar to domestic
sewage in their composition and in their effects upon
receiving bodies of water. The danger from patho-
genic organisms in packinghouse or slaughterhouse
wastes, however, is slight. In the absence of ade-
quate dilution the principal deleterious effects of
meat plant wastes are oxygen depletion, sludge de-
posits, discoloration, and general nuisance conditions.
Remedial Measures
PLANT PRACTICES
The prevention of meat and meat byproduct
waste is an economic necessity. Such losses are
costly because of product loss, product degradation
and because of the amount of expense connected
with waste treatment. Chart 1 shows the segrega-
tion of packinghouse wastewater.
REDUCTION OF SOLIDS
The first step in reducing such losses is to initiate
plant procedures for minimizing the solids discharged
along with the wastewater. These solids consist of
fat or fatty residues that are lighter than water and
fatty residues and other solida that are heavier than
water. The latter are termed settleable solids.
There are also some dissolved solids and nonsettleable
solids (suspended solids) in the waste effluent.
SCREENING SEWER OPENINGS
Every effort possible should be made to prevent
solids from being discharged with the effluent. One
effective measure is to screen all sewer openings.
However, the screens should be of sufficient area so
as not to clog frequently, thereby requiring frequent
attention to keep them open. Screening is especially
necessary in killing floor operations and in the prepa-
ration of variety meats. Floors should be dry-
cleaned before being washed.
SEGREGATION OF PAUNCH CONTENTS
Several municipal sewage treatment plants have
been designed with effective facilities for removing
paunch manure from packing plant wastewater.
However where such facilities are not available, it
may be necessary to remove these materials at the
source.
If removal is necessary, arrangements should be
made to segregate paunch and stomach contents so
that they will not be discharged to the sewers. A
rather effective method is to empty the paunch
contents into a receiving tank from which they are
pumped onto vibrating screens superimposed upon
an elevated holding bin. The paunch contents are
removed from this bin in trucks for disposal as refuse
or as fertilizer.
Screening not only reduces the solidB discharged
with the effluent, but also materially lowers the
5-day BOD and grease.
e
-------
Hasher-Washer Water
Skimmings
fo Inedible
Rendering
To Reuse or
Cooling Towers
Solids to
Disposal
or Vibrating
Screen
r-
Vibraf mg
Screen
(if required)
Solids
Skimmings
fo Inedible
Rendering
Roof ond
Yard Drains
Jockef water - vacuum ptjmpt;
oir ond ammonia compressors
Air conditioner wafer
Lard chill water
Canned meats chili water
Ammonia condenser water
Steam condenser wafer
Steam condensate
Stockyards
Calf and beef holding pens
Blending areas (cleanup wafer)
Stomach contents
Scalding tub
Debarring machine overflow
Half wasK water
Water softener blowdown
blood and tankage processing
and storage areas
Meot scrap storage areas
Casing wash water
Lord, follow and greose
storage areas
Took car wojb ond loading
Meat scrap expo Her area
Sausage preparation and
stuffing rooms
Canned meets
Smoked meat curing areas
Sausage cook tanks
Smokehouses
Processed meat packaging
Kill and cut floors
Boning rooms
Rendering cooker charging
lo Pubile Sewer jQ Sform
or Additional Treatment fVnin
Chart I. Segregation of packinghouse wastewater
FAT RECOVERY
Catch basins (gravity separators) should be in-
stalled to receive the water from viscera hashers and
washers, so as to collect the fat for rendering as
close to the source of production as possible. Similar
equipment should be installed for collecting the fat
from gutters beneath the dressing rails on the killing
floor.
Clear rendered grease such as that from a smoke-
house should be caught in small sanitary catch basins
which can be skimmed at frequent intervals. Col-
lecting the grease near its source of production
guarantees an improved quality for sale and elimi-
nates its actual loss by emulsification when dis-
charged into a large volume of effluent. This
advantage should, however, be balanced against the
labor cost of operating individual small basins.
Gravity separators which are not equipped with
automatic skimmers and sludge collectors should be
emptied once every 24 hours, at a time when there
is little flow. The settlings should be cleaned out
and disposed of with the paunch manure.
LIVESTOCK PENS
Livestock pens should be drycleaned, removing
the manure from the pens rather than flushing it
down the sewers.
BLOOD RECOVERY
All blood should be carefully collected and proc-
essed. Blood has a 5-day BOD of about 100,000
p.p.m. and a color that persists even in very high
dilutions. Very small amounts of blood will raise
the contaminating effect of the effluent sharply.
Blood curbing and gutters should be in good repair
to prevent shed blood from escaping into the dressing
area where it will be sewered. Blood solids may be
coagulated by sparging with live steam and then
separated from the water by discharge over a vibrat-
ing screen. The water from this process still has a
5-day BOD of about 30,000 p.p.m. and a high color
so it should be evaporated if possible. Drying the
whole blood in a tankage drier eliminates the problem
of handling the blood water separately.
WET RENDERING WASTES
When the steam rendering system is used all tank
water and press water should be recovered, skimmed
free of grease, and if economically possible, evapo-
rated. Tank water has a high 5-day BOD (30,000
p.p.m.).
CASING SLIMES
Slimes from the cleaning of casings should be
collected and coagulated by heat. After passage
over a vibrating screen, the coagulated material may
be dried and incorporated in dried tankage or dry-
rendered cracklings.
7
-------
TREATMENT
Meat plant wastes are amenable to biological
treatment in plants of the type in common use for
treatment of domestic sewage. Most meat plant
wastes are discharged to a public sewer system for
treatment at the municipal sewage treatment plant
prior to discharge to a receiving stream. This
method of handling the industrial wastes should be
entirely investigated before embarking upon design
of separate waste water treatment facilities. It is
important that the meat plant officials discuss and
reach agreement with both State water pollution
control authorities and municipal sewage treatment
officials before making a final decision as to the
treatment and disposal of the wastewater.
Trickling filters are commonly used in muni-
cipalities which receive meat plant wastes. Typical
installations are those at Cedar Rapids, Waterloo,
and Fort Dodge, Iowa; Oklahoma City, Okla.;
and South St. Paul, Minn. Chicago, 111.; Indian-
apolis, Ind.; Milwaukee and Madison, Wis., operate
activated sludge plants which receive packinghouse
wastes with the domestic, commercial, and other
industrial wastewaters.
The degree of pretreatment required prior to
discharge of packinghouse wastes to the public
sewer ranges from none in Omaha and South St.
Paul to 85 percent removal of BOD in Madison, Wis.
The most common pretreatment requirements
include screening to remove large solids and gravity
separation of grease.
Primary Treatment
Units commonly employed in primary treatment
include vibrating screens, grit channels, flocculation,
sedimentation, and dissolved air flotation. Johnson
(14) showed suspended solids removal of 80 percent
and total volatile solids reduction of 54 percent using
a grit tank followed by flocculation and sedimenta-
tion. The use of dissolved air flotation resulted in
BOD reductions of 42 percent with suspended solids
and grease reduced 48 and 52 percent, respectively.
Chemical coagulation has been employed in some
plants to improve removals by primary treatment.
Johnson (14) showed addition of alum increased
BOD removal 2.5 mg./l. and grease removal 1.5
mg./l. for each mg./l. of alum added. Nemerow (22)
states grease reductions of up to 90 percent can be
obtained through the use of chemicals and dissolved
air flotation. High operating cost with low invest-
ment are associated with chemical treatment.
Secondary Treatment
Trickling Filter«
Trickling filters containing rock sizes from 2}£ to
4 inches are used in treating packinghouse wastes.
Removals on a first stage trickling filter equal or
exceed that of the design curve developed by the
National Research Council (20). A plant in
Kochelle, III., constructed in 1961 uses three-stage
filters following grit removal, flocculation, and
sedimentation, to achieve 95 percent BOD removal.
A two-stage trickling filter plant in Madison, Wis.,
accomplishes 85 percent BOD removal. It is
necessary to provide recirculation for the filters for
periods of low flow at night and on weekends to
prevent ice formation during the winter months.
An hydraulic profile of a two-stage trickling filter
is shown in figure 1.
Irrigation
Irrigation has been used as a method of disposal
of pretreated meat plant wastes. Soil type, climate,
and crop determine the area requirements for this
disposal method. Seasonal loadings between April
and December in Wisconsin averaged 8,000 gal./
day/acre with the BOD of the irrigated wastewater
as high as 480 mg./l. and suspended solids of 280
mg./l.
REBUILT
TRICKLING FILTER
FIRST STAGE
Jep tout
Rock 860,0 -7
INTERMEDIATE
SEDIMENTATION
TANK
FIRST STAGE
RECIRCULATION
SECOND
STAGE
LIFT PUMPS
ML.847.6
ML . 849.0
foctrsubtton riot
PRIMARY PLANT
EFFLUENT
UspcMl y Sludyt
Pump
REBUILT
TRICKLING FILTER
SECOND STAGE
Tbpfow
fae*&6Q,0
FINAL
SEDIMENTATION RECIRCULATION
TANKS PUMP
8S4.+0 —7 Outfall Sews/
v.Z'Cwc.3ox
Mi'oW.L,
651.50
u
843.40
fi*circvl»t/0s> ftp
Sftidt• to _
Figure 1. Trickling filter plant
8
-------
The Moditted Anaerobic Contact Process
Anaerobic organisms are especially suited to the
destruction of organic matter in meat packing plant
waste waters. They thrive best on wastes contain-
ing significant concentrations of organic solids and
require temperatures of 90 to 95° F. for reasonably
efficient metabolism. Packing plant wastes are
usually warm (80 to 87° F.) and contain a sufficient
concentration of organic matter to produce a
quantity of methane gas which, when burned, will
raise the waste temperature to the required level
with little, if any, additional fuel required. Some
other food processing wastes are also in this category,
but most other industrial wastes are not.
The first full-scale modified anaerobic contact
process for the treatment of meat packing plant
wastes was placed in operation in December, 1959,
at the Wilson & Co., Inc. plant at Albert Lea, Minn.
(19, 24, 28, 29, 30, 31). The design was based upon
pilot scale studies conducted initially by Geo. A.
Hormel & Co. and later by the American Meat
Institute at Austin, Minn. (8, 25), and upon studies
on a first-stage plant built by Wilson & Co., Inc.,
and sized to treat half the waste water from the
Albert Lea plant. Other plants of this type built
since 1959 are located at Austin, Minn., to treat
wastes from the Hormel plant and at Momence,
111., to treat wastes from the Agar Packing Co.
Figure 2 shows the flow plan of the completed plant
at Albert Lea. The remainder of this section
relates to that plant.
The full-scale plant at Albert Lea is equipped with
an equalizing tank to provide storage for equalizing
the flow over a full 24-hour period. Digestion takes
place in two concrete digesters with tight concrete
covers, into which the raw wastes, preheated to 90 to
95° F., are discharged. The detention time in the di-
gesters is 12 to 13 hours, based upon the flow of raw
wastes. In the digesters, anaerobic organisms are
mixed with the wastes to digest the organic matter,
yielding methane, carbon dioxide, and bacterial cells
as end products. The solids in the mixed liquor (sus-
pended solids concentration 7,000 to 12,000 mg./l)
are digesting actively as the mixed liquor leaves the
digesters. The mixed liquor is then discharged
through vacuum degasifiers, operating at 20 inches of
vacuum, to two sludge separation tanks where the
sludge settles by gravity. The degasifiers remove
residual gases to facilitate gravity separation.
The plant at Austin utilizes air to release the
residual gases and operates at a lower BOD loading
than the plant at Albert Lea. The Austin plant
EQUALIZER
DEGASIFIER
DIGESTER
No. 2
DIGESTER
No. 1
WET
WELL
HEATER
SLUDGE
SEPARATOR
No. )
RETURN SLUDGE
TO DIGESTER
SLUDGE
SUMPS
SLUDGE
SEPARATOR
No. 2
WASTE SLUDGE
TO LAGOON
MAIN >¦
CONTROL
BLDG
OXIDATION
PONDS
FINAL
EFFLUENT
Figure 2. Flow plan, anaerobic contact process,
Albert Lea, Minn.
removes 96 percent of the BOD at loadings 0.059
pounds per cubic foot per day, treating a raw waste
of 1,400 mg./l. BOD.
The sludge is returned to the digesters as seed to
maintain the anaerobic culture. The detention
time in the separators is about 1 hour, based on
total flow, including sludge circulating through the
system at three volumes per volume of incoming
raw waste. The surface settling rate is about 300
gallons per square foot per day, based on raw flow
only. In spite of the fact that the residual gases are
removed in the degasifiers, the sludge is still floe-
culent and must be removed with a suction-type
rather than scraper-type sludge removal mechanism.
The treated effluent overflows through weir
troughs to two oxidation ponds for final polishing.
The ponds are 3.7 acres in area and 3 to 4 feet deep,
and reduce the BOD of the anaerobic effluent 50
to 70 percent, producing an oxygenated final effluent
suitable for discharge into Albert Lea Lake.
The anaerobic contact process is similar in many
respects to the activated sludge process commonly
used in aerobic treatment of municipal wastes and
9
-------
DEGASIFIERS
DIGESTERS
375.40
To Vacuum
Source
WL.878.0
IKLM9.40
64-9.40
847. IS
feturr Sludge Pipe
SEPARATORS
W.L856.qpr ,
£ff/uent
Outfall Sewer
— El. 870
— 860
— 850
— 840
— El. 830
PRIMARY PUNT
EFFLUENT
Excess Sludge ^ |
1t> Disposal
Return Sludge
Pump
Figure 3. Anaerobic contact plant
of some industrial waste waters. As in the activated
sludge process, the treatment is largely one of
contact between the organisms and the nutrient in
a favorable environment. After contact, the sludge,
consisting of organisms and agglomerated organic
matter, is separated from the treated liquid and
returned to the process to serve as seed for in-
coming wastes. The organisms digest the organic
matter in the sludge mass during the recycling and
treating process. A hydraulic profile of the anaer-
obic contact process is shown in figure 3.
Operating data representing the average of all kill
days in the year 1960 are shown in table 5. The
data are based upon analyses of samples composited
automatically in proportion to the flow. These
results compare favorably with results obtainable
in the most refined aerobic waste treatment processes.
The relative capacity of the anaerobic process in
removing BOD is shown graphically in figure 4. It
will be noted that the anaerobic process regularly
removed 1,000 to 1,450 mg./l. of BOD, while the
oxidation ponds remove a much smaller proportion
of the load. However, the oxidation ponds act as
shock absorbers, producing a final effluent of rela-
tively uniform quality under a considerably wide
range of loading. The first pond, which is usually
anaerobic, accounts for most of the BOD removed
in the pond system. (See table 6.)
Stabilisation Ponds /or Meat Packing Waste**
DEVELOPMENT IN MEAT INDUSTRY
Since most meat processing plants are located in
urban areas where land is relatively expensive, and
since meat packing wastes are amenable to treatment
•Portions of this section are taken from "Stabilization Ponds for Meat
Packing Wastes" by A. J. Steffen and are reprinted with permission from
Journal Water Pollution Control Federation, vol. 3S, No. 4, p. 440 (April
1963), Washington, D.C.
in conventional aerobic systems, the adoption of
stabilization basins by this industry has been some-
what slow. However, the popularity of stabilization
basins, both for complete and partial treatment of
meat packing wastewaters, has increased in recent
years, partly stimulated by developments in the
municipal field and partly by research in anaerobic
fermentation. The ponds may be used as tertiary
treatment following conventional aerobic systems or
anaerobic contact systems; or they may be used as
1600
1500
1400
1300
1200
1100
1000
900
800
700
600
500
400
300
200
100
••
. .. . 1
rrr
1
~
1
I
i
i
!
n
1
l
1
1
S3
1
1
I
1
1
1
i
I
1
1
1
1
1
i
1
1
1
1
1
1
1
1
1
|
1
i
1
1
1
1
1
1
1
1
1
1
1
1
I
1
1
3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
I
1
1
1
1
1
I
I
1
1
1
!
1
1
1
1
I
1
I
1
1
1
1
1
1
I
1
1
1
I
1
1
1
1
1
I
I
I
1
1
1
i
1
1
1
1
1
1
1
|
1
1
1
I
1
1
1
1
1
1
1
1
1
|
1
1
1
1
1
1
!
1
1
I
l
1
1
1
1
!
1
1
1
1
1
1
|
1
1
1
I
l
1
1
1
1
1
1
i
I
1
1
I
1
1
1
1
I
1
1
1
1
1
i
i
1
1
1
1
1
1
1
1
I
i
1
1
1
1
1
i
1
i
_
rr
I
i
1
i
1
1
1
1
1
1
i
1
1
1
&
1
¦tpp
m
jg
mm
_
ss
..."
April May June July
Week Endings 1960
Aug.
Sep».
[WVi mg/1 BOD Removed by Anaerobic Unit
mg/1 BOD Removed by Pondi
mg/l BOD Pond Number 1 Effluent-
Figure 4. Weekly average BOD data
lO
-------
Table 5.—Average operating data (all killing days in 1960)
Flow, gallons
Raw waste
Anaerobic process
effluent
Pond
effluent
Loss in
ponds
1,410,000
1,410,000
772,000
638,000
Raw waste
Anaerobic process
effluent
Plant effluent cor-
rected for seepage
mg./l.
Pounds
mg./l.
Pounds
mg./l.
Pounds
BOD
1, 381
998
822
2, 100
560
2, 540
1, 700
300
1, 400
16, 220
11, 610
10, 370
36, 500
6, 500
30, 000
19, 980
3, 520
16, 460
129
198
153
2, 080
560
1, 520
800
300
500
1, 517
2, 325
1, 800
24, 450
6, 500
17, 950
9, 400
3, 520
5, 880
26
23
20
1,076
560
516
367
300
67
304
268
232
12, 500
6, 500
6, 000
4, 310
3, 520
790
Suspended solids
Suspended volatile solids . . _ ._ —
Total solids .. ..
Total solids—water supply .. —
Total solids after deducting TS in water supply
Total volatile solids.. — ..
Total volatile solids in water supply
Total volatile solids after deducting TVS in
water supply.. . — —
secondary treatment, either as two-stage anaerobic-
aerobic systems or single-stage aerobic basins, fol-
lowing primary grease and solids separation; or they
may be used as complete treatment following con-
ventional grease recovery.
With so many different types of systems in use,
any attempt at generalization is difficult and uncer-
tain. Variations in the character of the raw waste,
in the degree of pretreatment, in the meat processing
operations, in waste conservation practices, in cli-
matic conditions, and in subsoil characteristics will
all affect the design. Some basins are anaerobic
by design, others by accident. Reported loadings
in conventional aerobic stabilization ponds range
from 50 lb./day/acre (3) treating raw meat packing
wastes in South Dakota, to 214 lb./day/acre for
relatively dilute processing wastes in Delaware
(BOD 175 mg./l.) following primary clarification
and equalization of flow (I). The latter system
consists of two ponds in parallel, 18 inches deep,
with a detention period of 2.89 days and BOD
reductions ranging from 96 percent in the summer
months to 70 percent in the winter months. The
extreme difference in loading in these two instances
illustrates the beneficial effects of primary clarifi-
cation.
OTHER EXAMPLES
Because meat packing wastes are warm (80 to
87° F.) and contain significant concentrations of
highly nutritive suspended organic solids, they are
especially responsive to anaerobic fermentation proc-
esses. The industry has found that raw wastes
can be treated effectively and economically in a
combination of anaerobic and aerobic ponds. The
first system of this type, designed from laboratory
and pilot scale data, is operating at the Swift & Co.
plant at Moultrie, Ga. (26), treating a meat packing
waste in an anaerobic lagoon 14 feet deep and 1.4
acres in surface area, followed by an aerobic lagoon
with a total area of 19.2 acres and a depth of 3 feet.
Table 6—Gperating data for oxidation ponds and treatment plant
Percent Removal
Digester
loading
lbs./cu.
ft./day
Through
anaerobic
unit
Through
ponds
Through
entire
plant
BOD
90. 8
80. 2
82. 8
79. 8
88.4
86. 8
98.2
97.6
97. 8
0. 156
0. 112
Suspended solids..
Suspended volatile solids.
11
-------
The detention time is 6 days in the anaerobic pond
and 19 days in the aerobic pond. The BOD loading
is about 0.014 lb./day/cu. ft. in the anaerobic stage,
and 50 lbs./day/acre in the aerobic stage, with an
overall BOD loading of 325 lbs./day/acre. Sludge
is recirculated in the anaerobic lagoon and effluent
is recirculated in the aerobic lagoon. The BOD of
the raw waste averaged 1,100 mg./l., and the effluent
averaged 67 mg./l. over a 4-year period. The second
system installed by the same packer (26) at Wilson,
N.C., consists of an anaerobic lagoon 17 feet deep
with 3.5 days detention, followed by trickling filter
treatment in the municipal plant.
A pond system treating meatpacking wastes in
New Zealand (34) consists of anaerobic ponds with
IK days detention, followed by an aerobic pond with
5 to 7 days detention, and yields 97 percent BOD
reduction. The anaerobic ponds are recirculated at
2 to 1, and the aerobic ponds at 0.6 to 1. The BOD
loading in the anaerobic system is 0.012 lb./day/cu.
ft.
A system in Virginia (35) consisting of primary
clarification followed by two %-acre ponds, each 8
feet deep, is loaded at a rate of 1,360 H>b./ of BOD/
day/acre. The average BOD of the wastes entering
the first pond, based on a year of record, was 1,135
mg./l.; the effluent of the first pond was 233 mg./l.,
and the final effluent was 82 mg./l. The first pond
is normally anaerboic, and the second is partly
aerobic with some algal growths. The BOD load-
ing on the second pond is 280 lbs./day/acre. The
good results, in spite of the heavy loading on these
ponds, indicate the benefits from presedimentation
and anaerobic fermentation.
A system in Idaho (36), entirely anaerboic, con-
sists of 3 ponds in series with an area of 2.8 acres, 8
feet deep, treating a raw BOD of 1,430 mg./l., and
discharging an effluent of 490 mg./l. at a BOD
loading of 520 lbs./day/acre. The results of this
plant are adversely affected by the discharge of
paunch manure and other solids to the pond. How-
ever, the high capacity of the anaerobic ponds for
BOD removal is evident.
Twelve small rural abattoirs in Louisiana are
successfully treating their entire wastes (4) in three-
stage pond systems, each consisting of an anaerobic
pond, a transitional pond, and an aerobic pond.
The entire paunch manure and grease are discharged
with the raw wastes to provide a mat on the anaero-
bic pond. Difficulties in the anaerobic stage of
treatment have been experienced wherever this mat
did not develop. Based upon an estimated BOD
of 2,000 mg./l. and a flow of 800 gallons per 1,000
pounds live weight kill, the anaerobic ponds were
designed at 30,000 pounds live weight kill/day/acre-
foot, the transitional ponds at 150,000 pounds, and
the aerobic ponds at 75,000 pounds. The anaerobic
pond is generally about 15 feet deep, and the transi-
tion and aerobic ponds about 4 feet deep. There is
no recirculation or supplemental heating in the
systems. An average of composite samples taken at
three plants gave a raw BOD of 2,270 mg./l., an-
aerobic effluent 183 mg./l., transition pond effluent
85 mg./l., and aerobic pond effluent 56 mg./l., with
an overall BOD removal of 98.5 percent.
STABILIZATION PONDS USED WITH ANAEROBIC
TREATMENT
Aerobic stabilization lagoons treat the effluent of
an anaerobic contact system receiving meat packing
wastes at the Wilson & Co., Inc., plant at Albert
Lea, Minn. (31). As shown in photograph (p. VI) and
figure 2, page 9, the two ponds at this plant, operat-
ing in series, are 3.7 acres in area and 3 to 4 feet
deep. Here, also, removal of suspended solids and
much of the BOD permits heavy loading in the
ponds. The average BOD loading during an entire
year of record was 410 lbs./day/acre, receiving a
waste averaging 129 mg./l. BOD and 198 mg./l.
suspended solids.
Of an average of 1.41 million gallons per day of
raw wastes, about 45 percent was lost in seepage and
evaporation from the ponds. Lobb at the beginning
of the year was 65 percent and at the end about 31
percent, indicating gradual sealing of the bottom of
the ponds. The ponds produce an effluent BOD
less than 30 mg./l., after correction for seepage (also
see "The Modified Anaerobic Contact Process").
Less than half of the total solids and only 18 percent
of the total volatile solids remaining in the effluent
represent solids added to the plant water in convert-
ing it to used water.
12
-------
Summary
Experience in the use of stabilization basins for
the treatment of meatpacking wastes falls into the
following general categories:
1. Complete treatment consisting of anaerobic
basins 8 to 17 feet deep, loaded at 0.011 to 0,015
lb. BOD/day/cu. ft., followed by conventional
aerobic stabilization lagoons loaded at 50 to 280
lbs. BOD/day/acre. Separate recirculation of both
stages improves treatment. Since meatpacking
wastes are warm (80 to 87° F.) and are excellent
nutrients, they are well suited to anaerobic treat-
ment.
2. Complete treatment by conventional aerobic
stabilization lagoons is limited to lower BOD load*
ings, possibly in the range of 50 lbe./day/acre, de-
pending on the degree of treatment desired.
3. Secondary treatment by aerobic stabilization
lagoons, following equalization of flow and primary
clarification, permits BOD loading in excess of
200 lbs./day/acre, with BOD removal ranging
from 96 percent in the summer to 70 percent in
the winter at temperatures as low as 36° F.
4. Tertiary treatment, following the anaerobic
contact process and utilizing conventional aerobic
stabilization lagoons, will successfully treat the
effluent of an anaerobic process containing an
average BOD of 129 mg./l. at an average loading of
410 Ibs./day/acre, and will produce an aerobic
effluent of lesB than 30 mg./l. BOD.
Bibliography
1. Anderson, J. S., and Kaplovsky, A. J., "Oxida-
tion Pond StudieB on Eviscerating Wastes from
Poultry Establishments." Proceedings of the
16th Industrial WaBte Conference, Purdue
University Extension Service, 109, 8 (1962).
2. Bragstad, R. E., "Industrial Wastes at Sioux
Falls, South Dakota." Proceedings of the First
Industrial Waste Conference, 22, Purdue Uni-
versity (1944).
3. Carl, C. E., and Kalda, D. C., "Waste Stabiliza-
tion Ponds in South Dakota." Proceedings of
the Symposium on Waste Stabilization Lagoons,
Public Health Service (1960).
4. Coerver, J. F., "Louisiana Practice and Experi-
ence with Anaerobic-Aerobic Pond Systems for
Treating Packinghouse Wastes." Journal Water
Pollution. Control Federation, 36, 5 (1964).
5. Cropsey, W. H., and Larson, K. D., 4'Sewage
Treatment at South St. Paul, Minnesota."
Sewage Works Journal, 19, 1051 (1947).
6. Dawson, F. M., and Kalinske, A. A., "Sympo-
sium on Grease Removal—Design and Operation
of Grease Interceptors." Sewage Works Jour-
nal, 16, 482 (1944).
7. Eldridge, E. F., "Industrial Waste Treatment
Processes and Plant Design." Michigan Engi-
neering Experiment Station Bulletin No. 82
(1938).
8. Fullen, W. J.» "Studies in the Anaerobic Diges-
tion of Packinghouse Waste." Proceedings of
the Third Conference on Research, American
Meat Institute, p. 63 (1950).
9. Gold, D. D., "Bibliography and Abstracts of
Articles Relating to Slaughterhouses and Pack-
ing House Wastes." Bulletin No. 14, Engineer-
ing Experiment Station, University of Tennessee.
(May, 1951).
10. Gold, D. D., "Summary of Treatment Methods
for Slaughter House and Packing House Wastes."
Bulletin No. 17, Engineering Experiment Sta-
tion, University of Tennessee. (May, 1953).
11. Gurnham, C. F., ed., "Industrial Wastewater
Control," Academic Press, Inc., New York,
(1964).
12. HowBon, L. R., "Packing House Waste Treat-
ment," (West Fargo, N. Dak.). Water Works
and Sewerage, 87, 217 (1940).
13. Huppert, J., "Chemical Treatment Plant for
Packing House Wastes." Sewage Works En-
gineering, 20,437 (1949).
14. Johnson, A. S., "Newer Aspects in Treatment
of Packing House and Feedlot Wastes," Trans-
actions, 14th Conference on Sanitary Engineer-
ing, University of Kansas, Lawrence, (1964).
15. Klassen, C. W., and Haefnrther, W. A,, "Treat-
ment of Wastes from Small Packing Houses.'"
Sewage Works Engineering, 20,136 (1949).
16. LeBo&quet, J., Jr., and Symona, G. E., "Buffalo
Sewer Authority," unpublished data.
17. Mohlman, F. W., "The Growing Importance of
13
-------
Industrial Waste Disposal." Water Works and
Sewerage, 87, 93 (1940).
18. National Provisioner, Inc., "Annual Meeting
Packers Guide." 1945, pp. 54, 94, 96; 1946,
pp. 63, 101, 84; 1947, pp. 69, 90.
19. National Provisioner, Inc., "Unique Wilson
Waste Plant Cuts BOD to Low Level." July
16, 1960, 143, No. 3, 26.
20. National Research Council, "Sewage Treatment
at Military Installations." Sewage Works Jour-
nal, 18, 5, 971 (May, 1946).
• 21. Nelson, D. H-, "Meat Packing Wastes and
Their Pretreatment." Sewage Works Engin-
eering, 20, 382 (1949).
22. Nemerow, N. L., "Theories and Practices of
Industrial Waste Treatment." Addison-Wesley
Publishing Co., Inc., Reading, Mass. (1963).
23. Ohio River Pollution Survey files.
24. Pietraszek, Gregory, "New Era in Treatment
of Packinghouse Wastes Opens with Successful
Start of Anaerobic Unit at Wilson Plant."
National Provisioner, 137, 2, 18 (July 13, 1957).
25. Schroepfer, G. J., Fullen, W. J., Johnson, A. S.,
Ziemke, N. R., and Anderson, J. J., "The
Anaerobic Contact Process as Applied to Pack-
inghouse Wastes." Sewage and Industrial
Wastes, 27, 4, 460 (April 1955).
26. Sollo, F. W., "Pond Treatment of Meat Packing
Plant Wastes." Proceedings of the 15th Indus-
trial Waste Conference, Purdue University
Extension Service, 106, 386 (1961).
27. Steffen, A. J., "What to do about Paunch
Wastes." Proceedings of the Third Waste
Conference; 268 Purdue University (1947).
28. Steffen, A. J., "Full-Scale Modified Digestion of
Meat Packing Wastes." Sewage and Industrial
Wastes, 27, 12, 1364 (December, 1955).
29. Steffen, A. J., "Treatment of Packinghouse
Wastes by Anaerobic Digestion." Chapters
1-12, "Biological Treatment of Sewage and
Industrial Wastes," Volume 2. "Anaerobic
Digestion and Solids-Liquid Separation," edited
by McCabe, Joseph, and Eckenfelder, W. W.
(Reinhold Publ. 1958).
30. Steffen, A. J., "The Modified Anaerobic Contact
Process." Proceedings of the 13th Research
Conference, American Meat Institute Founda-
tion, University of Chicago (March, 1961).
31. Steffen, A. J., and Bedker, M., "Operation on
Full Scale Anaerobic Contact Treatment Plant
For Meat Packing Wastes." Proceedings of
the 16th Industrial Waste Conference, Purdue
University Extension Service, 109, 423 (1962).
32. U.S. Public Health Service, unpublished data.
33. West Virginia Water Commission, "Slaughter
House Waste Treatment Guide." Charleston,
W. Va. (1946).
34. Data supplied by owner (1961).
35. Data supplied by owner and Virginia State
Water Control Board (1962).
36. Data supplied by owner (1962).
14
U.S. GOVERNMENT PRINTINO OFFICE:IMS O—785-0H
------- |