Group 1, Phase II
Development Document for
Proposed Effluent Limitations Guidelines
and New Source Performance Standards
for the
POULTRY
Segment of the
MEAT PRODUCT AND RENDERING PROCESS
Point Source Category
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
APRIL 1975
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DEVELOPMENT DOCUMENT
for
PROPOSED EFFLUENT LIMITATIONS GUIDELINES
and
NEW SOURCE PERFORMANCE STANDARDS
for the
POULTRY PROCESSING POINT SOURCE CATEGORY
Russell E. Train
Administrator
James L. Agee
Assistant Administrator for Water and
Hazardous Materials
. Allen Cywin
Director, Effluent Guidelines Division
Jeffery D. Denit
Project Officer
April 1975
Effluent Guidelines Division
Office of Water and Hazarous Materials
U. S. Environmental Protection Agency
Washington, D. C. 20460
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ABSTRACT
This document presents the findings of an extensive study of the
poultry processing industry by the Environmental Protection
Agency for the purpose of developing effluent limitations
guidelines, limitations of performance and pretreatment standards
for the industry, to implement Sections 301, 304(b) 307 and 306
of the Federal Water Pollution Control Act Amendments of 1972
(the "Act") ,
The poultry processing plants included in the study were plants
that slaughter, dress and/or further process poultry, including
rabbits and other small game; plants that process eggs or
manufacture such products as canned soups and TV dinners are
excluded from the study. There are five subcategories in the
poultry processing industry; four are based on type of bird
slaughtered, and one is plants that further process only.
Effluent limitations are set forth for the degree of effluent
reduction attainable through the application of the "Best
Practicable Control Technology Currently Available,» and the
"Best Available Technology Economically Achievable," which must
be achieved by existing point sources by July 1, 1977, and July
1, 1983, respectively. The "Standards of Performance for New
Sources" set forth the degree of effluent reduction which is
achievable through the application of the best available
demonstrated control technology, processes, operating methods, or
other alternatives. The proposed recommendations require the
best biological treatment technology currently available for
discharge into navigable water bodies by July 1, 1977, and for
new source performance limitations. This technology is
represented by water recirculation in flow away systems,
anaerobic plus aerobic lagoons or their equivalent, and
chlorination. The cost to the industry to implement the waste
treatment to achieve the 1977 limitations is estimated at $13.9
million. New source limitations incorporate the 1977 limitations
and an ammonia limitation. The recommendations for July 1, 1983,
are for the best biological treatment and in-plant controls, as
represented by dry offal handling systems; improved in-plant
primary treatment such as dissolved air flotation, and
microscreen, sand filter, or equivalent in solids controls; in
addition to the waste treatment system required for the 1977
limitations. Ammonia reduction by nitrification or air stripping
will be required if the effluent exceeds the ammonia limitations.
When sufficient suitable land is available, land disposal by
irrigation with no discharge may be the most economical waste
treatment option. The cost for the 1983 limitations is estimated
at $38.6 million for the poultry industry.
Supportive data and rationale for development of the proposed
effluent limitations and limitations of performance are contained
in this report.
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CONTENTS
Section
I. CONCLUSIONS *
II. RECOMMENDATIONS 3
III. INTRODUCTION 5
Purpose and Authority 5
Summary of Methods Used for Development of the Effluent
Limitations Guidelines and Standards of Performance 6
General Description of the Industry 10
General Process Description 17
Poultry Slaughter Manufacturing Processes 21
Receiving 21
Killing and Bleeding 22
Defeathering 23
Evisceration 24
Chilling and Packaging 25
Subprocesses 2&
Poultry Further Processing Manufacturing Process 27
Receiving, Storage, and Shipping 27
Thawing 2S
Cutting and Boning 29
Grinding, Chopping, and Dicing 29
Cooking 30
Batter and Breading 31
Mixing and Blending 32
Stuffing and Injecting 32
Canning 33
Final Product Preparation 35
Freezing 35
Packaging 36
Anticipated Industry Growth 36
IV. INDUSTRY CATEGORIZATION 37
C at egori zat ion 3 7
Rationale for Categorization 38
Type of Raw Material 38
Finished Product 40
Processing Operations 41
Plant Size 41
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CONTENTS (Continued)
oAction
V.
VI.
VII.
Plant Age and Location
Waste Water Characteristics and Treatability
WATER USE AND WASTE CHARACTERIZATION
Waste Water Characteristics
Raw Waste Characteristics
Discussion of Raw Wastes
Process Waste Water Flow Diagrams
Water Use-waste Load Relationships
Sources of Waste Water and Waste Load
Killing and Bleeding
Scalding
Defeathering
Evisceration
Chilling
By-Product Recovery
Further Processing
Rendering Plant Condensate and Condenser Water
SELECTION OF POLLUTANT PARAMETERS
Selected Parameters
Rationale for Selection of Identified Parameters
5-Day Biochemical Oxygen Demand (BOD5)
Chemical Oxygen Demand (COD)
Suspended Solids (TSS)
Total Dissolved Solids (TDS)
Total Volatile Solids (TVS)
Grease
Ammonia Nitrogen
Kjeldahl Nitrogen
Nitrates and Nitrites
Phosphorus
Chloride
Fecal Coliform
pH, Acidity, and Alkalinity
Temperature
CONTROL AND TREATMENT TECHNOLOGY
Summary
In-Plant Control Techniques
By-Product Recovery (Screening)
42
45
45
45
53
59
59
62
62
64
64
65
66
66
67
68
69
69
69
69
71
71
73
74
75
75
77
77
78
79
79
80
81
83
83
83
86
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CONTENTS (Continued)
St.-r I ion Page
VLi. CONTUOL AND TREATMENT TECHNOLOGY (Continued)
In-Plant Primary Treatment 89
Flow Equalization 39
Screens 89
Catch Basins 90
Dissolved Air Flotation 91
Electrocoagulation 95
Waste Water Treatment Systems 97
Anaerobic Processes 97
Aerated Lagoons 100
Aerobic Lagoons 100
Activated Sludge 102
Extended Aeration 104
Rotating Biological Contactor 105
Advanced Waste Treatment 107
Chemical Precipitation 107
Sand Filter 108
Microscreen/Microstrainer 113
Nitrogen Control 117
Nitrification/Denitrification 121
Ammonia Stripping 123
Breakpoint Chlorination 124
Spray/Flood Irrigation 125
Ion Exchange 129
VIII. COST, ENERGY, AND NONWATER QUALITY ASPECTS 133
Summary 133
"Typical" Plant 137
Waste Treatment Systems 140
Treatment and Control Costs 143
In-Plant Control Costs 143
Investment Costs Assumptions 143
Annual Costs Assumptions 146
Energy Requirements 147
Nonwater Pollution by Waste Treatment Systems 149
Solid Wastes 149
Air Pollution 151
Noise 152
Vll
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Introduction
CONTENTS (Continued)
Section
IX. EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION
OF THE BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY
AVAILABLE—EFFLUENT LIMITATIONS GUIDELINES 153
153
Effluent Reduction Attainable Through the Application
of Best Pollution control Technology Currently
Available 154
Identification of Best Practicable Control Technology
Currently Available 158
Rationale for the Selection of Best Practicable
Control Technology Currently Available 159
Size, Age, Processes Employed, Location of Facilities ieo
Total Cost of Application in Relation to Effluent
Reduction Benefits 160
Data Presentation 160
Engineering Aspects of Control Technique Applications 154
Process Changes 164
Nonwater Quality Environmental Impact 165
EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION
OF THE BEST AVAILABLE TECHNOLOGY ECONOMICALLY
ACHIEVABLE—EFFLUENT LIMITATIONS GUIDELINES 167
Introduction 167
Effluent Reduction Attainable Through Application of
the Best Available Technology Economically Achievable 153
Identification of Best Available Technology
Economically Achievable 172
Rationale for Selection of the Best Available
Technology Economically Achievable 174
Age of Equipment and Facilities 175
Total Cost of Application 175
Engineering Aspects of Control Technique Application 175
vni
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CONTENTS (Continued)
Section
Process Changes 176
Nonwater Quality Impact 17(>
XI. NEW SOURCE PERFORMANCE STANDARDS 177
Introduction 177
Effluent Reduction Attainable for New Sources 177
Identification of New Source Control Technology 178
Pretreatment Requirements 181
XII. ACKNOWLEDGMENTS 182
XIII. REFERENCES 183
XIV. GLOSSARY 189
IX
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TABLES
Number
1 Comparison of Production and Questionnaire
Respondent Distribution Among Geographical
Regions in the Country 9
2 Federally Inspected Poultry Slaughter, Cut-Up, and
Further Processed Volume, by Product Class, 1970 12
3 Poultry: Slaughtered under Federal Inspection,
United States, by Classes, 1969-1971 13
4 Average Live and Eviscerated Weights by Type of Poultry 14
5 Production of Broilers, Mature Chickens, and Turkeys,
by Region, 1970 15
6 Leading Ten states in Production of Broilers, Mature
Chickens, and Turkeys, 1970 16
7 Civilian Per Capita Consumption (Pound) 18
8 Production, Waste Water Flow, and Raw Waste Loading
of Plants in Each Subcategory 43
9 Raw Waste Characteristics of Chicken Processors 48
10 Raw Waste Characteristics of Turkey Processors 49
11 Raw Waste Characteristics of Fowl Processors 51
12 Raw Waste Characteristics of Duck Processors 52
13 Raw Waste Characteristics of Further Processing Only 54
14 The Number of Plants in the Questionnaire Sample
Reporting the Use of Various Manufacturing Processes
Within Each Sutcategory 57
1UA Effluent Quality from Conventional Filtration of
Various Biologically Treated Wastewaters 112
143 Performance of Microstrainers in Tertiary
Treatment of Biologically Treated Wastewater 116
14C Selected Results for Nitrogen Control in
Effluents 120
15 Typical Plant Operating Parameters Used for Estimating
Cost of Meeting Effluent Limitations 134
16 Additional Investment Cost for "Typical" Plants in Each
Subcategory to Implement Each Indicated Level of 135
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TABLES (Continued)
Number FaSe
Treatment, No Previous Expenditure Included 135
17 Addition to the Total Annual Cost and Operating Cost
for a Plant in Each Subcategory to Operate Treatment
System as Described 138
18 Additions to the Annual Cost and Operating Cost Per
Unit of Production for a Plant in Each Subcategory
to Operate Treatment System as Described 139
19 Waste Treatment Systems, Their Use and Effectiveness 141
20 Industry Breakdown by Subcategory, Size, and Type
of Waste Treatment 142
21 Waste Treatment System Configurations for Cost
Effectiveness Curves 147
22 Sludge Volume Generation by Waste Treatment Systems 150
23 Recommended Effluent Limitations for July 1, 1977 155
2U Effluent Limitation Adjustment Factors for Onsite
Rendering and Further Processing 156
25 Waste Treatment Data for Exemplary Chicken, Turkey,
and Duck Plants 161
26 Recommended Effluent Limitation Guidelines for
July 1, 1983 169
27 Effluent Limitation Adjustment Factors for Onsite
Rendering and Further Processing 170
28 Capital Investment, Operating and Total Annual Costs
for New Point Sources 179
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FIGURES
Number Page
I General Process Flowsheet tor Poultry Processina 19
2 General Process Flowsheet for Poultry Further
Processing 20
3 Categorization of Poultry Processing Industry 39
4 Average Waste Water Volume Generated Per Bird in
Processing Plants by Subcategory 55
5 Average Raw Waste Loading of Waste Water From Plants
in Each Subcategory 56
6 Product and Waste Water Flow for Typical Poultry
Processing Plants 60
7 Process and Waste Water Flow for Further Processing 61
8 Approximate Relationship Between Raw Waste Loading of
BOD5 and Waste Water Volume Per Bird for Chicken and
Turkey Plants 63
9 Suggested Poultry Processing Industry Waste Reduction
Program 84
10 Dissolved Air Flotation 93
11 Process Alternatives for Dissolved Air Flotation 94
12 Activated Sludge Process 103
13 Chemical Precipitation 109
HI Sand Filter System 109
15 Microscreen/Microstrainer 114
16 Nitrification/Denitrification 118
17 Ammonia Stripping 126
18 Spray/Flood Irrigation System 126
19 Ion Exchange 130
20 Waste Treatment Cost Effectiveness at Flow of 1.1U
Million Liters/Day 114
21 Waste Treatment Cost Effectiveness at Flow of 3 Million
Liters/Day 145
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SECTION I
CONCLUSIONS
A conclusion of this study is that the poultry processing
industry comprises five sufacategories:
Chicken processing
Turkey processing
Fowl processing
Duck processing
Further processing only
The primary criteria for establishing these categories were type
of raw material, i.e., kind of poultry, and raw waste load as
measured by 5-day biochemical oxygen demand (BOD5) in the plant
waste water. The type of production process was an important
consideration in establishing a separate category for plants that
further process only. Information and data on the type of
finished product, on plant parameters such as size, age, and
location, and on other pollutants in the waste water and the
treatability of those wastes all support the industry
categorization.
The wastes from all subcategories are amenable to biological
treatment processes, and no materials harmful to municipal waste
treatment processes were found.
The 1977 discharge limits for BOD5, suspended solids, and grease
are based on actual performance data for waste treatment systems
in the poultry processing industry. These limits are being met
by plants in each subcategory having onsite waste treatment
systems. These limits plus a fecal coliform limit are proposed
for 1977, The same limits plus a limit for ammonia are
recommended for new source limitations. It is estimated that the
industry will have to invest about $14 million capital to achieve
the proposed 1977 limits.
For 1983, effluent limits were determined as the best achievable
in the industry for BODj>» suspended solids, Kjeldahl nitrogen,
ammonia, nitrites and nitrates, phosphorus, and fecal coliform.
The industry will have to invest about $39 million to achieve the
proposed 1983 limits. The latest reported annual capital
expenditures by the industry are $60 million for each of the
three years, 1970, 1971, and 1972. It is further concluded that
where suitable and adequate land is available, land disposal by
irrigation with no discharge may be a more economical option for
meeting the discharge limits, especially for small plants.
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SECTION II
RECOMMENDATIONS
Limitations recommendations for discharge to navigable waters by
poultry processing plants for July 1, 1977, are based on the
performance of well-operated biological treatment plants in use
by the industry. The range in the limitations among the various
subcategories, in terms of live/weight killed (LWK) or finished
product (FP) as appropriate, are summarized below:
BOD5: 0.39 to 0.77 kg/kkg LWK and 0.30 kg/kkg FP;
Suspended Solids: 0.57 to 0.90 kg/kkg LWK and
0.35 kg/kkg FP;
Grease: 0.14 to 0.25 kg/kkg LWK and 0.10 kg/kkg FP;
Fecal Coliform: 400 counts/100 ml.
Adjustments in BOD5, suspended solids, and grease are provided
for dressing plants that further process, and/or render; and a
method is explained for accounting for duck processors which may
discharge to a common sewer with a duck feedlot.
Recommended New Source standards are the same as the 1977
limitations, with the addition of 0.14 to 0.26 kg ammonia per kkg
LWK and 0.1 kg ammonia per kkg FP.
Limitations recommended for the poultry industry for 1983 are
considerably more stringent and for BOD£, suspended solids, and
grease are based on the best performance of the treatment systems
and in-plant controls now in use in the poultry industry. In
addition to limits on the waste parameters included in 1977,
limits are set for ammonia. The discharge limits for ammonia are
set at the concentration limits achievable by the best available
technology, rather than at a limit related to production level.
Adjustments are provided for BOD^, suspended solids, and grease
for dressing plants that further process and/or render.
Duck plants with an onsite feedlot are subject to the combined
processor regulation and 1983 feedlot regulations of no discharge
from the feedlot. Thus the adjustment for processors is provided
for only that portion of waste load due t.o the processing
operation.
In cases where suitable and adequate land is available, land
disposal by irrigation with no discharge may be a more economical
option for meeting the discharge limits, especially for small
plants.
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SECTION III
INTRODUCTION
PURPOSE AND AUTHORITY
Section 301 (b)
Amendments of
later than July
sources, other
based on the
of the Federal Water Pollution Control Act
1972 (the "Act") requires the achievement by not
1, 1977r of effluent limitations for point
than publicly-owned treatment works, which are
application of the best practicable control
technology currently available as defined by the Administrator
pursuant to Section 304 (b) of the Act. Section 301 (b) also
requires the achievement by not later than July 1, 1983, of
effluent limitations for point sources, other than publicly-owned
treatment works, which are based on the application of the best
available technology economically achievable which will result in
reasonable further progress toward the national goal of
eliminating the discharge of all pollutants, as determined in
accordance with regulations issued by the Administrator pursuant
to Section 304(b) of the Act. Section 306 of the Act requires
the achievement by new sources of a Federal limitation of
performance providing for the control of the discharge of
pollutants which reflects the greatest degree of effluent
reduction which th-a Administrator determines to be achievable
through the application of the best available demonstrated
control technology, processes, operating methods, or other
alternatives, including, where practicable, a limitation
permitting no discnarge of pollutants.
Section 304(b) of the Act requires the Administrator to publish
regulations providing guidelines for effluent limitations setting
forth the degree of effluent reduction attainable through the
application of the best practicable control technology currently
available and the degree of effluent reduction attainable through
the application of the best control measures and practices
achievable including treatment techniques, process and procedure
innovations, operation methods and other alternatives. The
regulations proposed herein set forth effluent limitations
guidelines pursuant to Section 304 (b) of the Act for the poultry
dressing and further processing industries subcategory within the
meat products source category.
Section 306 of the Act requires the Administrator, within one
year after a category of sources is included in a list published
pursuant to Section 306(b) (1) (A) of the Act, to propose
regulations establishing Federal limitations of performance for
new sources within such categories. The Administrator published
in the Federal Register of January 16, 1973 (38 F.R. 1624), a
list of 27 source categories. Publication of the list
constituted announcement of the Administrator's intention of
establishing, under Section 306, limitations of performance
applicable to new sources for the source category of plants
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engaged in the dressing and further processing of poultry,
was included in the list published January 16, 1973.
which
SUMMARY OF METHODS USED FOR.DEVELOPMENT OF THE EFFLUENT
LIMITATIONS GUIDELINES AND STANDARDS OF PERFORMANCE
The effluent limitations guidelines and limitations of
performance proposed herein were developed in the following
manner. The point source category was first studied for the
purpose of determining whether separate limitations and
limitations are appropriate for different segments within a point
source category. This analysis included a determination of
whether differences in animal type, raw material used, product
produced, manufacturing process employed, equipment, age, size,
waste water constituents, and other factors require development
of separate effluent limitations and limitations for different
segments of the point source category. The raw waste
characteristics for each segment were then identified. This
included an analysis of (1) the source and volume of water used
in the process employed and the source of waste and waste waters
in the plant; and (2) the constituents (including thermal) of all
waste waters, including toxic constituents and other constituents
which produce taste, odor, or color in water or aquatic
organisms. The constituents of waste waters which should be
subject to effluent limitations guidelines and limitations of
performance were identified (see Section VI).
The full range of control and treatment technologies existing
within the point source category was identified. This included
identification of each distinct control and treatment technology,
of the amount of constituents (including thermal), and the
chemical, physical, and biological characteristics of pollutants,
and of the effluent level resulting from the application of each
treatment and control technology. The required implementation
time was also identified. In addition, the nonwater-quality
environmental impact, such as the effects of the application of
such technologies upon other pollution problems, including air,
solid waste, and noise, were also identified. The energy
requirements of each of the control and treatment technologies
were identified as well as the cost of the application of such
technologies.
The information, as outlined above, was then evaluated in order
to determine what levels of technology constituted the "best
practicable control technology currently available,11 "best
available technology economically achievable," and the "best
available demonstrated control technology, processes, operating
methods, or other alternatives." In identifying such
technologies, various factors were considered. These included
the total cost of application of technology in relation to the
effluent quality achieved, equipment and facilities involved, the
process employed, the engineering aspects of the application of
various types of control techniques, process changes, nonwater-
quality environmental impact (including energy requirements), and
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other factors. Once the alternative wastewater treatment systems
corresponding to the three levels of technology described above
had been determined, limitations on the discharge of pollutants
attainable by the technology appropriate to each level were
established. The nature and extent of data available for each
subcategory determined the precise method by which the ettluent
limits were developed.
To the extent possible, the limitations for BPCTCA were derived
as averages of the actual effluent discharge from the best
treatment systems identified in the subcategory. In some cases
it was not possible to employ this methodology because of limited
data on the performance of treatment systems in a subcategory.
In these instances, limits were based on the performance of
whatever plants in the category could be considered exemplary.
In cases where there were few such plants, limits were then
verified by comparison with known pollutant concentrations in
effluent from plants in these categories (or other categories
with similar wastes and treatment facilities) and the average
flow for plants within the category. Where effluent data were
not available at "all, the effluent limits were derived in the
first instance by means of this procedure. Multiple regression
analyses were also used to verify the relationship between
limitations on different pollutant parameters.
The data for identification and analysis were derived from a
number of sources. These sources included Refuse Act Permit
Program data; EPA research information; data and information from
North Star files and reports; a voluntary questionnaire issued
through the National Broiler Council, Poultry Science
Association, Poultry and Egg Institute of America, Southeastern
Poultry and Egg Association, Poultry Industry Manufacturer's
Council, Arkansas Poultry Federation, National Turkey Federation,
Pacific Egg and Poultry Processors Association, Mississippi
Poultry Improvement Association, and Alabama Poultry and Egg
Association; and onsite visits and interviews at several
exemplary poultry processing plants in various areas of the
United States, All references used in developing the guidelines
for effluent limitations and limitations of performance for new
sources reported herein are included in Section XIII of this
document.
The data base was primarily comprised of data from questionnaires
and plant waste water sampling. It included 152 poultry
processing plants. There were 92 questionnaire responses from
chicken processing plants. Based on the number of birds
reportedly slaughtered by each plant per day, these 92 chicken
processing plants account for about 63 percent of the total
number of chickens slaughtered by Federally inspected plants.
There were 34 questionnaire responses from turkey processing
plants. These 34 plants slaughter approximately 61 percent of
the total number of turkeys slaughtered. There were seven
questionnaire responses from fowl processing plants and these
seven plants slaughter 37 percent of the total number of fowl
slaughtered. The five duck processing plants that returned
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questionnaires account for 51 percent of the duck slaughter by
number. There were five further processing only plants that
returned questionnaires.
Questionnaires were also received from nine plants that slaughter
more than one category of bird or that process other poultry.
The plants include the following: one plant that slaughters
chickens and turkeys; one plant that slaughters geese, ducks, and
capons; one plant that slaughters and processes ducks, fowl,
broilers, and turkeys; one plant that slaughters chickens and
Cornish hens (very young chickens, about 5 weeks old); one plant
that slaughters Cornish hens only; one plant that slaughters
squab; one plant that slaughters ducks and turkeys; one plant
that cuts and packages fresh poultry; and two rabbit slaughter
plants, i
The geographical distribution of the plants responding to the
questionnaire is shown in Table 1. As can be seen, the live
weight production distribution and the distribution of the
questionnaire respondents among the regions of the country are
very similar.
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Table 1. Comparison of Production and Questionnaire Respondent
Distribution among Geographic Regions in the Country*
Region**
North Atlantic
North Central
South Atlantic
South Central
West
Total
Broilers
Production
5.5%
2.9
41.9
44.9
4.8
100.0%
Ques t ionnair es
3.3%
1.1
43.5
48.8
3.3
100.0%
Fowl
Production
14.0%
25.6
23.4
24.7
12.3
100.0%
Questionnaires
0%
28.6
28.6
28.6
14.2
100.0%
Turkeys
Production
2.7%
41.8
17.1
15.7
22.7
100.0%
Questionnaires
2.9%
47.1
11.8
8.8
29.4
100.0%
V0
*Note: Production figures reported in more detail in Figure 3.
**STATES IN POULTRY REGIONS
North Atlantic
Maine
New Hampshire
Vermont
Massachusetts
Rhode Island
Connecticut
New York
New Jersey
Pennsylvania
North Central
Ohio
Indiana
Illinois
Michigan
Wisconsin
Minnesota
Iowa
Missouri
Nebraska
Kansas
South Atlantic
Delaware
Maryland
Virginia
West Virginia
North Carolina
South Carolina
Georgia
Florida
South Central
Kentucky
Tennessee
Alabama
Mississippi
Arkansas
Louisiana
Oklahoma
Texas
West
Idaho
Colorado
Arizona
Utah
Washington
Oregon
California
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GENERAL DESCRIPTION OF THE INDUSTRY
The poultry processing industry falls within SIC Code 2016, which
includes young and mature chickens, turkeys, and other poultry
slaughtering, dressing (evisceration), and ice or freeze packing,
and that part of SIC Code 2017 dealing only with poultry (e.g.,
chicken and other poultry canning and freezing or related
processing into specialty items). Young chickens include
broilers-fryers and other young immature birds such as roasters
and capons; mature chickens are fowl from breeder and market egg
flocks and stags and cocks; turkeys include fryer-roasters, which
are young immature birds, usually under 16 weeks of age, young
turkeys grown to a mature market age, usually 5 to 7 months, and
old turkeys which are fully matured birds held for egg
production, usually over 15 months of age; other poultry includes
ducks, geese, guineas, squabs, pigeons, partridge, pheasants, and
rabbits and small game. Excluded from this study were those
portions of SIC 2017 dealing with egg processing and plants
manufacturing such products as canned soups and TV dinners.
Plants within the industry carry out the operations of
slaughtering, dressing, and further processing of broilers,
chickens, fowl (mature chickens), turkeys, ducks, geese, other
birds, and rabbits and other small game. Some plants only
slaughter and dress (eviscerate), others slaughter, dress and
further process; and still others further process only.
Occasionally, poultry slaughterhouses have rendering operations
on the same site but housed separately.
The products of slaughtering and eviscerating operations are
icepacked or chilled ready-to-cook broilers and chickens, fresh
or frozen fowl, turkeys, etc. Further processing following
slaughter and dressing operations converts poultry into a variety
of cooked, canned, and processed poultry meat items such as pre-
cooked breaded parts, roasts, rolls, patties, meat slices in
gravy, canned boned chicken, and various sausages. The amount of
further processing performed in poultry slaughterhouses varies
considerably. Some plants may process only a part of their kill
while others may process their own kill plus birds from other
plants. Most of the further processing in slaughterhouses is
limited to cutting, cooking, batter coating and breading,
browning, and freezing. The type and number of operations
carried out in plants that further process only vary
considerably, resulting in a wide variety of finished products.
The usual practice in turkey plants is to slaughter only during
seven to nine months of the year. If the plant also further
processes, it will usually produce processed products during the
entire year.
The poultry industry is typified by vertical integration from
hatchery through feed mill, slaughtering, processing, arid
wholesale marketing under contract. The slaughtering and
processing plants are therefore integral parts of a larger
system. For example, the typical integrated broiler firm has its
10
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own hatchery, feed mill, and processing plant, and depends almost
entirely on contract production. The firm may be local, a
subsidiary of a national feed company or meat packer, or a part
of a large conglomerate. Turkey and duck slaughtering and
processing firms tend to follow a similar pattern; however, fowl
or mature chickens tend to be a byproduct of commercial egg
production. The vast majority of poultry production is in
broilers, turkeys and mature chickens (fowl). This can be seen
in Table 2 which shows the weights by class in 1970 for
slaughtered, cut-up, and further processed poultry in Federally
inspected plants. Young chickens (which include broilers) and
all turkeys accounted for 93 percent of the total slaughter.
Young chickens accounted for over 90 percent of the total cut-up
volume; while turkeys, mature chickens, and young chickens
accounted for over 93 percent of the total further processed
volume. In 1970, plants under Federal inspection slaughtered
over 90 percent of the total U. S. production of young chickens,
mature chickens and turkeys.
Table 3 shows the numbers and pounds (both live weight and
eviscerated or ready-to-cook weight) of Federally inspected
poultry by class for 1969 through 1971. From the data in Table 3
on pounds slaughtered by type of bird, the average live weight,
eviscerated weight, and yield were calculated for each type.
These are given in Table 4.
In 1973, according to the USDA, there were 248 Federally
inspected poultry plants that slaughter only, 288 that process
only, and 144 that slaughter and process.2 However, it is
believed that a majority of the 288 process-only plants produce
products such as canned soups and TV dinners or are otherwise
excluded from this point source category. These plants, as
previously mentioned, do not fall within the scope of this
program and will not be considered in this report. Also plants
handling both poultry and red meat are excluded.
Poultry is produced in nearly every State of the United States.
However the largest production of broilers and turkeys is highly
concentrated by geographic area. Furthermore, poultry production
(hatching and growing) is carried out within close proximity to
slaughtering and dressing Operations. Table 5 shows the
production of broilers, mature chickens and turkeys by region for
1970. This table shows that the South Atlantic and South Central
regions account for 86.8 percent of the broiler production; 48.1
percent of the mature chicken production, and, 32.8 percent of the
turkey production. Table 6 shows the production in live weight
for broilers, mature chickens, and turkeys for the leading ten
States in 1970. The top ten States in broiler production, which
are mainly from the South Atlantic and South Central regions,
account for 84 percent of the total U. S. production. The top
ten States in turkey production produced 75 percent of the U. S.
turkey output in 1970. However, turkey production is not as
highly concentrated regionally as broiler production, with the
two largest regions—West North Central and West—accounting for
52 percent of the U. S. production in 1970. Production of fowl
11
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Table 2. Federally Inspected Poultry Slaughter, Cut-up, and
Further Processed Volume, by Product Class, 1970
Category
Slaughtered (1,000 pounds live weight)
Percentage of total slaughter
Cut-up (1,000 pounds ready-to-cook)
Percentage of total cut-up
Further processed (1,000 pounds ready-
to-cook)
Percentage of total further processed
Young
Chickens
*
10,073,725
77.7
1,842,594
90.2
337,292
26.2
Mature
Chickens
**
810,555
6.3
8,608
0.4
392,404
30 . 3
Turkeys
t
1,987,715
15.3
190,713
9.3
479,427
37.1
Other
Poultry
ft
81,860
0.7
2,230
0.1
83,274
6.4
Total
Poultry
12,953,825
100.0
2,044,145
100.0
1,292,397
100.0,
*Young chickens are commercially grown broilers-fryers and other young immature birds such as
roasters and capons.
**Mature chickens are fowl from breeder and market egg flocks and stags and cocks.
tlncludes fryer-roasters which are young immature birds, usually under 16 weeks of age; young
turkeys grown to a matured market age, usually 5 to 7 months; and old turkeys which are fully
matured birds held for egg production, usually over 15 months of age.
ttlncludes ducks, geese, guineas, squabs, pigeons, partridge, pheasants, and rabbits.
Source: Based on data from Slaughter Under Federal Inspection and Poultry Used in Further
Processing, SRS-USDA, Pou 2-1(2-71).
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Table 3. Poultry: Slaughtered under Federal Inspection,
United States, by Classes, 1969-19713
Class
Young chickens
Mature chickens
Total chickens
Young turkeys
Old turkeys
Fryer-roaster turkeys
Total turkeys
Ducks
Other poultry
Total poultry
Class
Young chickens
Mature chickens
Total chickens
Young turkeys
Old turkeys
Fryer-roaster turkeys
Total turkeys
Ducks
Other poultry
Total poultry
Number Inspected
1969
Thousands
2,516,287
153,767
2,670,054
84,476
1,245
9,651
95,372
11,589
1970
Thousands
2,770,178
176,116
2,946,294
92,990
1,058
11,501
105,549
11,883
1971
Thousands
2,778,971
183,194
2,962,165
98,226
1,199
12,319
111,744
11,030
Pounds Certified (Ready-to-Cook)
1969
Thousands
6,484,117
454,400
6,938,517
1,344,352
18,886
69,548
1,432,786
51,133
4,438
8,426,874
1970
Thousands
7,161,141
516,336
7,677,477
1,468,038
16,315
82,157
1,566,510
52,617
5,023
9,301,627
1971
Thousands
7,281.021
523,884
7,804,905
1,536,241
18,353
87,018
1,641,612
49,413
6,147
9,502,077
Pounds Inspected (Liv.e Weight)
1969
Thousands
9,064,962
710,935
9,775,897
1,693,643
23,881
89,618
1,807,142
72,018
6,898
11,661,955
1970
Thousands
10,073,724
810,554
10,884,278
1,860,995
20,667
106,053
1,987,715
74,042
7,789
12,953,824
1971
Thousands
10,223,510
825,265
11,048,775
1,949,966
23,496
112,588
2,086,050
69,341
9,526
13,213,692
u>
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Table 4. Average Live and Eviscerated Weights by Type of Poultry
Class
Young chickens
Mature chickens
Young turkeys
Old turkeys
Eryer^roast-er- turkey...
Ducks
Live Weight
kg, (pounds)
1.7 (3-7)
2.1 (4.6)
9.1 (20.0)
8.8 (19.4)
4.2. (9.2.>
2.8 (6.2)
Eviscerated Weight,
kg, (pounds)
1.2 (2.6)
1.3 (2.9)
7.2 (15.8)
6.9 (15.3)
3.2 (7.X)
2.0 (4.4)
Yield,
percent
70.0
63.0
79.2
79.0
77.2
71.0
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Table 5. Production of Broilers, Mature Chickens,
and Turkeys, by Region,.1970l
Region*
North Atlantic
East North Central
West North Central
South Atlantic
South Central
West
United States (48)
Broilers
594,356
(5-5)**
155,086
(1.4)
161,984
(1.5)
4,528,245
(41.9)
4,855,432
(44.9)
506,740
(4.8)
10,801,843
(100.0)
Mature
Chickens
167,156
(14.0)
145,191
(12.1)
160,664
(13.5)
278,502
(23.4)
295,965
(24.7)
147,457
(12.3)
1,194,935
(100.0)
Turkeys
59,828
(2.7)
273,188
(12.5)
638,712
(29.3)
372,638
(17.1)
341,901
(15.7)
498,186
(22.7)
2,184,453
(100.0)
STATES IN POULTRY REGIONS
North Atlantic
Maine
New Hampshire
Vermont
Massachusetts
Rhode Island
Connecticut
New York
New Jersey
Pennsylvania
South Atlantic
Delaware
Maryland
Virginia
West Virginia
North Carolina
South Carolina
Georgia
Florida
Western
Idaho
Colorado
Arizona
Utah
Washington
Oregon
California
South Central
Kentucky
Tennessee
Alabama
Mississippi
Arkansas
Louisiana
Oklahoma
Texas
East North Central
Ohio
Indiana
Illinois
Michigan
Wisconsin
West North Central
Minnesota
Iowa
Missouri
Nebraska
Kansas
** Numbers in parentheses are regional shares of United States total
15
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Table 6. Leading Ten States in Production of Broilers,
Mature Chickens, and Turkeys, 1970 ^
Broilers
State
Georgia
Arkansas
Alabama
North Carolina
Mississippi
Maryland
Texas
Delaware
California
Maine
Total
Production
(Live Weight)
1000 Pounds
1,577,149
1,539,126
1,313,981
1,137,295
892,660
722,452
662,591
521,535
338,922
321,510
9,027,221
Mature Chickens
State
California
Georgia
Arkansas
North Carolina
Pennsylvania
Alabama
Mississippi
Texas .
Florida
Indiana
Total
Production
(Live Weight)
1000 Pounds
102,824
100,546
84,582
72,026
63,558
61,265
51,006
46,037
44,144
42,441
668,429
Turkeys
State
California
Minnesota
North Carolina
Texas
Missouri
Arkansas
Iowa
Indiana
Utah
Virginia
Total
Production
(Live Weight)
1000 Pounds
302,834
302,677
175,959
169,150
158,979
143,081
122,015
93,374
85,294
77,451
1,630,814
Source: Based on data from Statistical Reporting Service, USDA.
-------
or mature chickens is less concentrated regionally than is that
for either broilers or turkeys, with the top ten States producing
only 56 percent of the U. S. production in 1970, Again the South
Atlantic and South Central regions are the largest regions in
mature chicken production, accounting for 48 percent of the
total.
Production of other poultry (and small game), such as geese,
ducks, rabbits, squabs, pigeons, partridge, pheasants and guineas
appears to be regionally concentrated. Geese production appears
to be mainly in Minnesota and the Dakotas; duck production,
mainly on Long Island, New York, and around Lake Michigan in
Indiana and Wisconsin; and rabbit production in Arkansas and
Kansas. Other poultry accounts for only 0.7 percent by live
weight of the total poultry processed (see Table 2), and ducks
account for about 90 percent of that (see Table 3).
The volume of all poultry slaughtered in Federally inspected
poultry plants increased from 8.1 to 13.2 billion pounds live
weight between 1961 and 1971—a 62 percent increase. In the same
period, the number of slaughtering plants decreased from 532 to
about 400. Civilian per capita consumption of poultry has also
increased dramatically over the years, as shown in Table 7.
Chicken per capita consumption, for example, has increased from
20.6 to 30.0 to 41.4 pounds for the years 1950, 1961, and 1971,
respectively. In fact. Table 7 shows that the combined turkey
and chicken consumption has increased more rapidly over the years
1950 to 1972 than that for all red meats.
Most poultry processing plants are located in or near urban
areas, primarily small towns, where labor and water are readily
available. Poultry processing plants—both slaughtering and
further processing are labor intensive operations. The
slaughtering or dressing plants, as mentioned previously, are
located near poultry production areas. However, plants that only
further process poultry may be located outside the production
areas.
GENERAL PROCESS DESCRIPTION
A general process flowsheet of a typical poultry slaughterhouse
is shown in Figure 1; that for further processing of poultry is
shown in Figure 2. The processing steps included in Figures 1
and 2 are not intended to be all-inclusive but to represent the
typical plant. For example, duck slaughtering includes a wax dip
operation not shown in Figure 1. In addition, some operations
depicted in Figure 2 may not be used in some plants, while some
other, less frequently used, processes are not included in Figure
2. Specific plant processes may also differ in order or
arrangement from that shown in Figure 2 for further processing
plants.
Some poultry plants that slaughter may also further process.
However, the information gathered during this study showed that
17
-------
Table 7. Civilian Per Capita Consumption (Pound)4
oc
1950
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
' 1969
1970
1971
1972*
i
'
Eggs
(No.)
389
371
369
362
354
352
335
329
327
318
318
3.14
313
320
316
310
311
314
307
Chickens
and
Turkeys
24.7
26.3
29.6
31.4
34.0
35.2
34.2
37.4
37.0
37.5
38.5
40.9
43.9
45.8
45.4
47.4
49.7
49.9
52.0
All
Chickens
20.6
21.3
24.4
25.5
28.1
28.9
28.1
30.0
30.0
30.7
31.1
33.4
36.1
37.2
37.4
39.1
41.5
41.4
42.9
Broilers
Only
8.7
13.8
17.3
19.1
22.0
22.8
23.4
25.8
25.7
27. Q
27.6
29.4
32.3
32.8
33.1
35.2
37.4
37.1
38.8
Turkeys
4.1
5.0
5.2
5.9
5.9
6.3
6.1
7.4
7.0
6.8
7.4
7.5
7.8
8.6
8.0
8.3
8.2
8.5
9.1
All
Red
Meats
145
163
167
159
152
160
161
160
163
170
175
167
171
178
183
182
186
192
189
Beef
and
Veal
71.4
91.4
94.9
93.4
87.2
87.1
91.2
93.4
94.4
99.4
105.1
104.7
108.8
110.3
113.3
114.1
116.6
115.7
118.2
Pork
69.2
66.8
67.3
61.1
60.2
67.6
64.9
62.0
63.5
65.4
65.4
58.7
58.1
64.1
66.2
65.0
66.4
73.0
67.4
Lamb
and
Mutton
4.0
4.6
4.5
4.2
4.2
4.8
4.8
5.1
5.2
4.9
4.2
3.7
4.0
3.9
3.7
3.4
3.3
3.1
3.3
*Preliminary
-------
WEIGHING,
GRADING
AND PACKAGING
SHIPPING
Figure 1. General Process Flowsheet For
Poultry Processing
19
-------
POULTRY
CARCASSES
RECEIVING
AND
STORAGE
FINAL
PRODUCT
PREPARATION
Figure 2. General Process Flowsheet For
Poultry Further Processing
20
-------
in the majority of the plants that do both, the further
processing operations usually involved cut-up, cooking, batter
and breadinqr deep frying, and freezing. The specialty products,
such as rolls, luncheon meats, patties, etc., are produced
primarily in further processing only plants, A few of these
plants—usually turkey plants—may slaughter during a specific
time of the year and further process for part or for the entire
year. The dressed birds can be frozen readily for later
processing. Most specialty products are produced for hotels,
restaurants, institutions, and fast-food outlets.
The major limitation manufacturing processes in most modern
poultry slaughtering or dressing plants—are receiving, killing,
bleeding, defeathering, eviscerating, chilling, and packing
(Figure 1). Associated with these processes are the subprocesses
of materials recovery and plant cleanup.
Most plants have "flow-away" systems for feathers and offal; in
these systems water in flumes is used to carry away the feathers
and offal, separately, to byproduct recovery, A few plants do
not have flow-away systems for feather and/or offal handling.
Kosher processing of poultry, for example, involves dry picking
and collecting of feathers. Other plants have replaced the wet
offal flow-away system with dry evisceration and offal handling.
This is to reduce water use and waste load. Rabbit dressing, of
course, includes skinning for pelt removal rather than scalding
and defeathering.
Receiving
Live birds are trucked to poultry processing plants in coops on
open trucks. The coops hold up to about 20 broiler-size
chickens. Normally, the trucking of birds to plants is scheduled
so that, the birds are held in the receiving area for a minimum
amount of time. Holding the birds too long results in increased
incidences of death and loss of birds. The greater the holding
time, also, the greater the pollution load in the receiving and
holding area for manure.
Coops containing the chickens are usually unloaded from the
trucks onto a conveyor system. The birds are then conveyed, in
the coops, to a hanging area where the birds are removed from the
coops and attached by their feet to shackles suspended from an
overhead conveyor line. Occasionally coops are permanently
attached to the trucks; the birds then are hung as they are
removed from the coops. The conveyor system, traveling at a
constant speed, now carries the shackled birds into the killing
area. Empty coops are returned to the trucks by conveyor,
normally without being cleaned. One or more overhead conveying
systems may be used in the receiving area or in the processing
21
-------
area, depending on the size of the plant, the plant layout, and
the number of birds to be killed that particular day.
Manure, feathers, and dirt are the major pollutants that
accumulate on the floor of the receiving area. When live poultry
are held for a relatively short time in a receiving area,
quantities of pollutants, except nitrogenous nutrients, are minor
compared to pollutants from other processes. However, extended
holding of poultry can add significant quantities of pollutants.
Forges5 reported that the waste from the storage of chickens was
32 pounds of BODj> and 35 pounds of suspended solids per thousand
chickens stored each day; Porges and Struzeski6 reported the
values as 36 and 40 pounds, respectively. Forges5 also reported
that the amount of BODji to the sewer is reduced to 5.0 pounds,
and the suspended solids to 6.0 pounds per thousand birds stored
daily, if dry cleanup is practiced in the receiving area. Waste
materials collected by dry cleaning are dumped as refuse or
loaded onto the offal truck along with the feathers, offal, and
blood, and sent to rendering. Relatively small quantities of
water are used in this area, following dry cleanup, to remove
residual material.
Killing and Bleeding
In most modern plants, birds are shocked just before or
immediately following killing . to facilitate bleeding.
Slaughtering of poultry is done by either severing the jugular
vein or by debraining. Manual and automatic mechanical severance
of the jugular vein are the common killing techniques in use
today. The killing area is usually a we11-contained area with
high walls on both sides of the conveyor line to restrict the'
drainable blood to this area. Such an arrangement is called a
"blood tunnel." Data collected show that chickens are held in
the tunnel from 45 to 125 seconds for draining the blood, with an
average time of 80 seconds; turkeys from 90 to 210 seconds with
an average time of 131 seconds.
Most poultry processing plants attempt to recover as much of the
free-draining blood as they can. Even under the best conditions
and with adequate drainage time—say two minutes—only about 70
percent of the blood in poultry is recovered in the killing area.
The blood is usually permitted to congeal on the killing floor
and is removed, as a semisolid, from once to several times a day,
depending on the cleanup procedures in the plant. A few plants
have recently installed troughs just below the bleeding birds to
collect blood. The blood is periodically removed from the trough
by vacuum, pump, or gravity flow. The blood trough should reduce
the waste load due to blood losses to the sewer.
Feathers, dirt, manure, and blood are pollutants that may find
their way into the sewer from the killing area; that of the
greatest significance is, of course, blood. Congealed blood and
other pollutants too difficult to remove by draining and dry
scraping are flushed to the sewer during cleanup.
22
-------
Blood that is collected in the killing area is usually mixed with
the feathers on the offal truck. A less common blood handling
process, but one that appears to be increasing in use involves
loading the blood into receiving tanks that are attached to, or
part of, the offal truck. Obviously, the storage of blood in
tanks is preferable, since blood dumped onto the feathers in an
offal truck can drain from the truck and into a sewer. If the
plant has onsite rendering, feathers and blood are frequently
handled separately to give higher quality rendered products.
Defeathering
After killing, the birds are scalded in either a scald tank or a
spray scald. Tank scalding is by far the most common. The
scalding of the bird helps to relax feather follicles for easier
feather removal. Water temperature in a scald tank was found in
this study to be between 51° and 60°C {124° and 140°F) with an
average of 53.3°C (128°F) for chickens, and between 52° and 63°C
(135° and 145°F) with an average of 59.5°C (139°F) for turkeys.
The feathers are removed mechanically after scalding. Usually
defeathering is accomplished by continuously passing the birds
through machines equipped with rubber fingers attached to
rotating drums; the fingers flail the birds, removing the
feathers. Simultaneously with the feather removal, warm water is
sprayed onto the birds as a lubricant, and to flush away feathers
as they are removed. In a few cases, mainly small or seasonal
operations, batch-type defeathering machines are used. This
requires that the birds be removed from the shackles, placed in
the machine, defeathered, and then replaced on the conveyor line
by hand. This type of defeathering obviously requires more
labor. The number and kind of defeathering machines used in a
plant depends on the type and size of the birds to be cleaned.
Feathers are usually conveyed from the defeathering area by water
in a flow-away system.
Following defeathering, the remaining pinfeathers are removed,
usually by hand. In duck processing plants, the pinfeathers are
removed by wax stripping. In this process, the birds are dipped
into molten wax and cooled with a spray of water to harden the
wax. Stripping away the hardened wax removes the pinfeathers.
The wax is reclaimed and reused. After defeathering, all birds
while on the conveyor are passed through a gas flame to singe the
remaining fine hairs and pinfeathers, washed, and transported
into the evisceration area.
Waste water from the defeathering operations results from the
following: continuous overflow from the scald tank; final dump of
the scald tank at the end of the operating day; feather flow-away
system; continuous water spray in the defeathering machines;
carcass washing; and washdown of the floors and equipment during
cleanup. The minimum overflow from the scald tank is about 1
liter (1/4 gallon) per bird.
23
-------
;-'eathers removed by the defeathering machines and flumed away in
the flow-away system contain manure, dirt, and blood. These
materials may be dissolved or suspended in the waste waters,
thereby contributing to the waste load from the defeathering
area. Feathers themselves should not contribute significantly to
the waste load because they can be easily removed from the water
by screening. Presently, considerable attention is being given
to the capture of feathers, since feathers escaping into sewers
are a major nuisance in sewage treatment.
Evisceration
The evisceration room is segregated from the killing, bleeding,
scalding, and defeathering areas of the plant to insure that
eviscerated birds are not exposed to cross-contamination from any
of the previous operations. Washing, chilling, packing, and
cutting of the eviscerated birds are carried out in the same
general plant area as evisceration,
When the birds enter the eviscerating area, their feet are
removed, usually with an automatic cutter. The feet are either
dry collected or flumed, usually in the feather flow-away system.
The birds are then re hung on a different conveyor line to
facilitate removal of the viscera and inspection.
On the evisceration line, the oil gland is removed; the
peritoneal cavity is opened, the viscera are pulled out and
exposed, and the carcass and entrails are inspected; the giblets
are recovered, trimmed, and washed; the inedible viscera are
discharged., usually to the offal flow-away system; the lungs are
removed by vacuum, raking, or by hand; the head is removed; and
finally, the neck is removed and washed. Cleaning of the gizzard
involves splitting, washing out the contents, peeling the inner
liner, and a final wash. The giblets (heart, liver, and gizzard)
are conveyed to giblet chillers. The inedible viscera may be
carried away by vacuum or mechanical conveying rather than by a
flow-away system if dry evisceration is used. The eviscerated
birds are thoroughly washed, both inside and outside, and
conveyed to chillers.
Potential pollutants from the evisceration process include feet,
heads, viscera, crop, windpipes, lungs, grit, sand and gravel,
flesh, fat, grease, and blood. Usually these are received by the
offal flow-away system which carries them to the screening room.
The screening removes the bulk of the suspended material;
however, some soluble organic matter, blood, grit, sand, fat,
grease, and flesh particles are not removed. The BOD5 level of
the waste water in this stream is only a few hundred mg per
liter, but the flow per thousand birds is so high that the total
BOD_5 load from the evisceration process is higher than from any
other process. It is not uncommon for evisceration to account
for 40 to 50 percent of the BOD5 load in the plant effluent.
24
-------
The major sources of water from evisceration are the flow-away
water, water from the many hand washers located on the
eviscerating trough, from the washers in the automatic gizzard
splitters, and from carcass washers.
Chilling and Packaging
Before the birds can be packed for shipment, they must be
chilled. Removal of the body heat is an important operation
because rapid cooling protects the meat flavor and quality and
lengthens the market life by preventing bacterial decomposition.
Almost all modern poultry processing plants rely on large
chilling tanks containing ice water. Several forms of chilling
tanks are in operation. One is a large enclosed drum which
rotates about a central axis; another is a perforated cylinder
mounted within a chilling vat; and still another type is a large
open chilling tank containing a mechanical rocker to provide
agitation. In all of these, birds cascade forward with the flow
of water.
Most poultry plants use several chilling tanks in series,
typically two or three. The flow, while carrying the birds
through the individual tanks, is c cunte re ur rent through the
series so the first chilling tank that the birds enter is warmer
than the next, and so on. In this arrangement, ice and
freshwater are added to the last chiller. The USDA requires one-
half gallon per bird overflow in the chillers; the flow typically
is about three-fourths of a gallon per bird. The effluent from
the first chiller is occasionally used in the offal flow-away
system. Normally the carcass of the bird is chilled within 30 to
40 minutes to an ultimate carcass temperature of 1°C
A similar, but separate and smaller, chilling system is used for
cooling giblets.
After the birds are chilled, they are rehung on a conveyor line
to allow the excess moisture to drain off. The birds are then
conveyed to an automatic weighing and separating area, and are
graded and packed or are routed to further processing.
Old and small plants, which do not use continuous flow and
chilling, cool the carcasses in batch tubs of ice and water with
bubblers for mixing. Cooled birds are then drained, sized,
graded, and packaged manually.
The majority of broilers are ice-packed or packed with dry ice.
Turkeys, ducks and exotic fowl are usually frozen; mature
chickens, which are used almost exclusively for further
processing, are sold either ice-packed or frozen. Freezing of
poultry produces no inherent waste water; ice-packing has very
little effect on waste water.
25
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Sutaprocesses
By-Product Recovery
The major byproducts of poultry slaughtering—blood, feathers
(skins) ff and offal—are recovered by nearly all plants. However,
grease recovery is not as effectively practiced by poultry
slaughtering plants as by meat packing plants,, Fortunately,
however, grease loads in poultry plants are not as great.
Wasting byproducts not only increases the waste load in plant
effluents, and hence treatment costs, but also wastes a valuable
raw material used by rendering plants in the production of
proteinaceous animal feeds. Small amounts of small game skins
and feathers are occasionally used in the production of products
such as rabbit skins for wearing apparel and feathers for
stuffing furniture and bedding items.
A 1970 survey by the USDA found that only 0«6 percent of the
plants did not salvage offal0 Of the 99.4 percent that recover
byproducts^ 70,8 percent of the plants sold offal to Tenderers, 1
percent gave offal to renderers, 26.6 percent rendered offal
onsite, and 1 percent dumped or burned the collected offal. The
same stud/ revealed that blood was salvaged by 8508 percent of
the plants. It was sold to renderers by 54.6 percent,, given away
by 7 percent, rendered onsite by 22,U percent, and dry disposed
by 1.8 percent. Feathers were not recovered by 0«4 percent of
the plants; they were salvaged arid sold by 71.,6 percent, given
away by 0.8 percent^ rendered onsite by 25-9 percent, and burned
or dumped by 1.3 percent.*
Removal of offal and fea-thers from flow-away waste water streams
is defined as byproduct recovery. Almost all plants use
screening equipment for this purpose. The most common equipment
arrangement is small mesh (to 200 irtesh) rotating or vibrating
screens followed by stationary protective screens (1/U- to 1/2-
inch openings) to collect any overflow. This arrangement will
remove the bulk of the solids-
Gravity separation basins or air flotation systems are usually
used following screening to remove grease and suspended solids.
This is defined as in-plant primary treatment. (A more detailed
description of primary treatment is found in Section VII of this
report-)
The byproducts, which are continuously screened from the flow-
away systems or are bulk handled in dry evisceration, are loaded
into offal trucks for delivery to rendering plants^ When the
offal is rendered onsite—at the processing plant location but in
a separate billding the byproduct materials may be conveyed
continuously to the rendering system.
Bloodff on t-ie other hand, is usually vacuumed or pumped from the
blood tunnel to a holding tank. Lungs are frequently mixed with
the blood in the holding tank0 These byproducts are either
dumped onto feathers in the offal truck or tanked for delivery to
the rendering plant. The latter is used if the renderer has
separate blood processing equipment. Otherwise the blood is
mixed with the feathers and they are rendered together.
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Plant Cleanup
Normal plant cleanup practice is for a light washdown of the
floor during short break periods; for a complete washdown of
floors, sometimes including the blood tunnel, and of most of the
processing equipment during the lunch break; and for a thorough
plant cleanup and general sanitation at the end of the processing
day. In addition, the floors and some processing equipment are
frequently rinsed just prior to the start of a production day.
Spills are cleaned up with water on an as-needed basis.
Maintenance of valves and hoses and use of high-pressure nozzles
can help to reduce the volume of water used for plant cleanup.
The waste load associated with plant cleanup can be further
reduced by dry sweeping and scraping floors and tables prior to
washdown. Gross solids collected by dry cleaning should be
placed in containers and sent to rendering. Dry cleaning of the
blood tunnel is particularly important because of the high
pollutional strength of blood.
POULTRY FURTHER PROCESSING MANUFACTURING PROCESS
The major limitation manufacturing processes in plants that
further process poultry are receiving and storage; thawing
operations; cutting and boning; dicing, grinding, and chopping;
cooking; batter and breading; mixing and blending; stuffing;
canning; final product preparation; freezing; packaging and
shipping. Because of the similar operations and facilities,
shipping is grouped with receiving and storage for the discussion
below. Associated with these processes are subprocesses of
product cooling and plant cleanup.
These manufacturing processes contribute in varying degrees to
the raw waste load from further processing operation. It should
be noted that the plant raw waste load includes the effect of in-
plant primary waste treatment. The source and relative amounts
of waste load for each manufacturing process are identified in
the following descriptions. Cleanup of equipment and processing
areas and the associated waste generated are also described in
the following discussions.
Receiving. Storage, and Shipping
Poultry meat used as raw material and nearly all the finished
products in a poultry processing plant, except certain canned
products, require refrigerated or freezer storage. Poultry-type
raw materials are brought into further processing plants as
carcasses, cut-up parts, and deboned meat, although the vast
majority is whole carcasses. Further processing plants that are
an adjunct operation to poultry slaughtering plants usually
receive fresh ice-packed poultry meat; plants isolated from raw
material sources usually receive frozen poultry meats.
Seasonings, spices, and chemicals are usually received in dry
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form and stored in dry areas convenient to sauce, spice, and
batter and breading formulation areas.
The cleaninq ot storage freezers is mainly a dry process and only
on rare occasions, such as defrosting of a treerer, would it
generate a wasto water load. Refrigerated storage space do^s
require daily wash down, particularly ot the floors whore meat
juices and particles have accumulated from the sorted materials.
Although the industry encourages dry cleaning of all floors
including storage areas prior to wash down, actual cleanup
practices frequently do not include the dry cleanup.
Shipping almost always involves truck transportation. Storage
includes the movement in and out of storage facilities within the
plant. The primary source of waste from these operations occurs
in the transport of raw materials between storage and processing
areas within the plant; transport of finished products and other
raw materials usually generates Ittle or no waste because of the
type of packaging used. Further processing raw material
transport is largely done in stainless steel carts or vats that
must be thoroughly washed and sanitized between uses; this
cleaning results in the loss of meat juices and particles into
the sewer.
Thawing
Frozen poultry carcasses and raw meat received by further
processing plants are thawed by immersion in or by spraying with
water, or by thawing in air. The raw material must be adequately
protected from cross-contamination. In immersion, poultry is
submerged in tanks or vats of lukewarm potable water for the time
required to thaw the poultry throughout. At no time should the
thawing media in which poultry is immersed exceed 21°C (70°F).
Ice or other cooling agents may be utilized if necessary to keep
the thawing water within the acceptable range. The vats used for
thawincr range from pushcarts of 10 to 20 cubic feet in volume to
permanently installed tanks up to about 50 feet in length. To
enhance thawing, water may be continuously added or flexible air
hoses may be inserted to induce agitation. In thawing units
which have no freshwater added (no overflow) or where the thawing
water leaves the unit for reconditioning prior to returning to
the thawing unit, the water is not allowed to exceed 10°C (50°F).
Complete thawing is necessary to permit thorough examination of
ready-to-cook poultry prior to any further processing. When the
poultry has adequately thawed for reinspection* the product is
removed from the water and drained. The practice of placing
frozen poultry into cooking kettles, without prior thawing, is
permitted only when representative samples of the entire lot have
been thawed and found to be in sound and wholesome condition.
Thawing may be accomplished in cookers where the water can be
heated to enable the cooking process to begin immediately
following completion of thawing. It is required that thawing
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practices and procedures result in no net gain in weight over the
frozen weight.
When whole carcasses or parts are thawed for repackaging as
parts, USDA regulations prohibit recooling the thawed parts in
slush ice. However, they may be held in tanks of crushed ice
with the drains open pending further processing or packaging.
Wet thawing of further processing raw materials generates the
largest quantity of contaminated waste water. The water used to
thaw the poultry is in contact with the meat and thereby extracts
water-soluble salts and accumulates particles of meat and fat.
The water used in thawing is dumped into the sewer during and/or
after thawing is complete. In addition, a waste load results
from cleanup of the thawing systems. The waste load generated in
dry thawing is from the thawing materials dripped on the floor
and the washing of these drippings into the sewer.
Cutting and Boning
Cutting of poultry is normally the first further processing step
for fresh ice-packed and just-thawed poultry. Cutting involves
disjointing and sawing of poultry into the normal parts such as
wings, breasts, and drumsticks. It also may include skinning.
The waste load generated from cutting results from the use of
water by the personnel involved in the operation during the
operating day and from cleanup of the floors and equipment. The
waste materials include skin, fat, meat tissue and bone dust.
The waste load from cutting does not appear to be large and can
be reduced to an insignificant amount by dry cleaning of floors
and equipment prior to washdown.
Boning is the separation of meat from bone. This can be done on
either raw or cooked poultry. Frequently turkeys, because of
their size, are boned raw; chickens and similarly sized poultry
are boned either way. The ultimate product use of poultry
usually determines whether a product is boned before or after
cooking. Raw boning is usually done by hand, whereas boning
cooked poultry can be done by hand, by mechanical means, or by a
combination of the two methods, providing all bone is removed.
The waste load from boning results from frequent washing of
knives, cutting boards, pans, and operators1 hands during the
operation day; from the rinsing of floors and tables during
breaks and lunch; and from the dismantling and cleaning of
mechanical equipment. The pollutants may include meat juices,
and meat and fat tissue. Bones are collected as raw material for
rendering.
Grinding, Chopping, and Dicing
Many poultry products, such as patties, rolls, and luncheon
meats, require size reduction of boned meat. Grinding, chopping,
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or dicing vary the degree of size reduction,, with grinding
producing the greatest degree of size reduction,, chopping the
next, and dicing the least. These operations are all
accomplished by mechanical equipment. In grinding^ the meat is
forced past a cutting blade and then extruded through orifice
plates having holes between 1/8 and 3/8 inch; chopping likewise
is usually accomplished by forcing the meat past a cutter and
through an orifice platec but with holes greater than 3/8 inch in
diameter. Dicing,; on the other hand, is more like a cutting
operation in that it makes distinct cuts in the meat to produce
square-shaped chunks of meat. Waste loads are generated from
these operations by spillage in handling and movement of
materials and in cleanup of equipment. These manufacturing
operations can be among the major contributors to the waste load
in poultry further processing plants as a result of equipment
cleanup. Because these processing steps involve size reduction
of poultry meats, meat and fat particles tend to coat equipment
surfaces and collect in crevices, recesses, and dead spaces
within the equipment* Of course^ tHe finer the particle size,
the greater the tendency for coating and hanging up of material
in the equipment. All of these materials are removed during
cleanup and are washed inro the sewer. Any piece of equipment
that is used in size reduction is cleaned at least once per
processing day and may be rinsed off periodically throughout the
dayp thereby contributing substantially to the waste load.
Cooking
All further processed poultry products are, by definition, cooked
at some point in processing- This is done in preparation of a
final product or in preparing whole birds for subsequent
deboning, the latter applying particularly in processing
chickens. Fully cooked poultry products are frequently prepared
in further processing operations, especially for the hotel,
restaurant., institution, and fast-food outlet market.
Most poultry products are cooked by immersion in water in steam-
jacketed ojcen vats. Gas-fired ovens are used for some products
and a small number of microwave ovens are also in use in place of
immersion cookers., Deep-fat frying is used for breaded products;
this is discussed in the following subsection, "Batter and
Breading. "
Chicken par is, whole birds, and products such as rolls and loaves
are cooked oy immersion in hot water cookers. Overflow wiers are
used in these cookers to collect edible chicken or turkey fat
during the actual cooking operation. At the end of the operating
day, the cooking vats are dumped to the sewer- The waste water
volume is small in comparison to the total water use in dressing
plants; i*; is more significant in plants that further process
only. However, the waste load is exceptionally high. A sample
of this v/aste water was found to contain a BOD5_ concentration of
17,000 mg/1. Spices and preservatives are added to the cooking
water. These additives plus other pollutants accumulate during
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the cooking of the poultry and contribute substantially to the
plant waste load.
The gas-fired ovens require essentially no water in their
operating cycle. A small quantity of steam may be added for
humidity control, but this is usually vented through the stack
system.
The use of microwave ovens frequently requires a preliminary
injection of spices and preservatives by means of multiple needle
injection equipment such as is used in ham and bacon processing.
The pickle solution remaining at the end of the operating day is
dumped into the sewer. The quantity of water is small, but
again, the strength is very high as a pollutant. A steam
atmosphere is used in some microwave ovens; this would produce a
small stream of condensate that may be a high-strength pollutant.
All cooked products are cooled before any further processing of
the product. The most common cooling technique is by immersion
in a cold-water vat which has a continuous overflow. This
overflow and the cleanup of the vat at the end of the day
generates a waste water stream of significance. Also because of
the direct contact between the poultry meat and the water, the
pollutant strength of the waste water is substantial.
Cleanup of these cookers requires dumping the liquid contents
followed by a thorough washdown of all surfaces exposed to the
poultry products. The cleanup after dumping results in a waste
water stream and waste load.
Batter and Breading
Fully cooked poultry parts or fresh fabricated products may be
battered and breaded to produce a desired finished product. The
batter is a water-based pumpable mixture, usually containing milk
and egg solids, flour, spices, and preservatives. A new batch of
batter is prepared each operating day. The batter is pumped
through the application equipment and the excess flows back to
the small holding tank. Some of the batter clings to the
application equipment and this is cleaned off during the day. At
the end of the day, the remaining batter is dumped to the sewer.
It is a very small quantity—between 5 and 10 gallons—although
it is certainly a high-strength pollutant.
The breading is a mixture of solids which are deposited on the
poultry product after the batter is applied to hold the breading
on. There is no liquid involved in breading the products, and
the residual solids are not disposed of into the sewer.
The breading is "set," "browned," or cooked by frying in deep
fat. The breaded products are conveyed through a deep-fat fryer
that is either directly gas fired or is heated by the circulation
of hot oil from a heater separate from the fryer. This vegetable
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oil is reused repeatedly, when the rare occasion occurs in which
the oil must be disposed of, the oil is shipped to a renderer,
rather than dumped to the sewer.
The cleanup of the batter and breading equipment results in some
waste water and waste load. However, the relatively small size
of the equipment results in a water volume and waste load from
cleanup that are relatively minor.
Mixing and Blending
Some of the further processed products include numerous
ingredients such as the ground or chopped meat, dry solids,
spices', and water. The required intermixing of these ingredients
will also vary, depending on the product, from a mild blending
action to an intensive high-shear mixing action. Gravies and
sauces are also prepared in mixers that usually include steam
jacketing. The ingredients are either pumped or manually
transported to the mixing equipment for the preparation of the
batches of the product mix..
Solid wast^ materials are generated from these operations by
spillage ir the handling and movement of materials and in cleanup
and preparation of equipment for different types of products.
These manufacturing operations are among the major contributors
to the wast? load in a poultry further processing only plant as a
result of equipment cleanup. Since this processing step involves
the intima :e mixing of meat and other materials in the
preparation of stable mixtures, these materials tend to coat
equipment surfaces and collect in crevices, recesses, and dead
spaces in equipment™ All of these materials are removed during
cleanup and washed into the sewer. This is in contrast to
larger-size particles that can be readily cleaned from a floor
prior to washdown and thereby reduce the raw waste load in the
waste water stream. Any piece of equipment that is used in any
of these operations is cleaned at least once per processing day
and may be rinsed off periodically throughout the day, thereby
generating a fairly substantial Quantity of waste water and
contributing to the raw waste load.
Stuffing and injecting
Following the preparation of a stable mixture of ingredients for
a processed poultry product, the mixture is transported either by
pump or in a container to a manufacturing operation where the
mixtures are formed into the finished products. Sausage casings
are commonly used as containers in this operation. Either
natural casings, which are animal intestines, or synthetic
casings may be used in producing these kinds of products.
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In casing stuffing, a product mixture is placed in a piece of
equipment from which the product mixture is either forced by air
pressure or is pumped to fill the container uniformly and
completely to form the shape of the finished product. Water is
used to lubricate casings for use in the stuffing operation.
Whole bird stuffing, primarily with turkeys, involves pumping a
stuffing mixture into the body cavity of the dressed bird at a
stuffing station, followed by trussing and freezing of the
stuffed bird.
Injection of whole birds with edible fats and oils, such as
butter, margarine, corn oil, and cottonseed oil, is often done to
enhance palatability. Again this is primarily done with turkey
carcasses. This is normally accomplished by inserting small
perforated needles into the carcass in such a manner as to direct
the injected fat or oil between the tissue fibers. It is
preferred tc inject longitudinally into the carcass without
penetrating the skin of the carcass. Thus the intact overlying
skin will retard escape of the injected materials. The injection
material can be used one day after preparation, but must be
dumped at the end of the second processing day. Most plants
minimize or avoid any dumping of this high-cost material by
preparing only the quantity that will be needed. When it is
dumped, it is discharged into the sewer.
The primary source of waste load and waste water occurs in the
cleanup of the equipment used in this operation. The residual
mixtures left in the equipment contribute significantly to the
waste load because of their propensity to stick to most surfaces
that they come in contact with and to fill crevices and voids.
All equipment used in this operation is dismantled at least once
a day for a thorough cleaning. Between preparation of different
products, the equipment may be rinsed off with clear water. The
end-of-the-day cleanup is designed to remove all remnants of the
mixtures handled by the equipment and this material is washed
with the waste water into the sewer, thereby contributing to the
waste load,
Some spillage of material occurs in this operation. Spillage
occurs during the transport of the material from grinding and
mixing to the stuffing operation, and particularly in the
stuffing injecting operation when the material being extruded
exceeds the capacity of the casing or whole bird, and overflows.
The containers used to hold the canned poultry food products must
be prepared before filling and covering. The cans are thoroughly
cleaned and sterilized. The wet cans are transported from the
preparation area to the processing area for filling and covering.
Water is frequently present all along the can lines from
preparation to filling and covering. The cans go through one
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last steaming just before entering the can filling area. Can
filling can be done by hand or mechanically. However, canning of
whole birds or disjointed parts necessitates hand filling.
Can filling by machine is a highly mechanized high-speed
operation. It requires the moving of the poultry food products
to the canning equipment and the automated delivery of those
products into a container. The combined high speed and design of
the equipment results in an appreciable amount of spillage of
product as the cans are filled and conveyed to the covering
equipment. At the can covering station a small amount of steam
is introduced under the cover or a light vacuum is pulled just
before the cover is sealed to create a vacuum within the can when
it cools. Steam use also generates a quantity of condensate
which drains off the cans and equipment onto the floor. The
operation of the filling and covering equipment results in a
substantial quantity of waste water containing product spills
that is wasted to the sewer. Filling cans by hand does not
appear to generate as much spillage. Canning plants that have
more than one filling and covering line will have a waste load
that is generally proportional to the number of such lines in
use.
All of the equipment used in filling and covering cans is washed
at least once per day at the end of the processing period. If a
can filling machine is to be used for different products during
the day, it will usually be cleaned between product runs.
Poultry products are frequently canned with gravy-type sauces.
This type of canned product results in greater contamination of
equipment wash water because of the tendency of the product
mixture to coat surfaces it comes in contact with and to fill all
dead spaces and crevices in the iequipment. Highly mechanized
equipment with many moving parts is designed to be cleaned intact
rather than being dismantled first, as is much of the grinding
and mixing equipment. Cleaning the equipment while it is intact
requires a high-velocity water stream or jet of steam to remove
all food particles from the equipment. The tendency of operating
personnel is to use greater quantities of water than necessary to
clean the equipment. This results in large quantities of waste
water with substantial waste loads from canning operations.
The equipment used in transporting the meat product to the can
filling stations also must be cleaned after it has been used on a
specific product, and it is always cleaned at the end of the
processing day. The product characteristics that contribute to
large waste loads, as described above, also generate large waste
loads in cleanup of the transport equipment as well.
Canned poultry food products are stabilized by heat processing to
destroy bacteria inside the canned product. This is accomplished
by cooking or by retorting, which is the pressurized cooking of
canned products. Live steam is used as the heating medium in
retorting, and it is common practice to bleed or vent steam from
the retort vessels to maintain the cooking pressure. Cooking
without pressure is used for cured boneless canned poultry
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products; the product is considered perishable and must be kept
refrigerated. virtually no waste water or waste load is
generated by the retorting or cooking operations unless a can in
a particular batch should accidentally open and spill its
contents; this requires the wasting of the contents of that can
and the cleanup of the cooking vessel. This rarely happens, and
the retorts or cooking vessels, as a matter of normal practice,
are not cleaned. The cans that are placed in cooking vessels are
normally free of any potential source of waste load,
Final Product Preparation
Many of the final products from a poultry plant that includes
further processing are ready to serve after heating and are
prepared for the hotel, restaurant, and institutional trade.
These products are portion controlled, may have gravy or a sauce
added, and are packaged in containers of an appropriate size and
design for immediate heating and serving. Poultry meat patties,
slices of turkey loaf, and chicken parts are examples of the type
of meat product prepared in this manner.
Equipment is used to convey, slice, and deposit the meat product
into containers. The same equipment delivers and adds the sauce
or gravy to the meat in the container, as required for specific
products. As the final operation, this equipment closes the
individual containers.
All of the equipment surfaces that contact the food products are
cleaned at the end of each processing day, A change in the
product during the day may require cleaning some components of
the equipment. Material spills are cleaned up immediately. All
of the materials washed from the equipment are carried to the
sewer in the wash water. The volume of water and the waste load
from cleanup are relatively small from this processing operation.
Freezing
The first step in the freezing of further processed poultry
products is usually accomplished by blast freezing, in which the
product is frozen by high-velocity air within the range of -29°
to -40°C (-20° to -40°F), or by first passing the product through
a carbon dioxide or nitrogen tunnel in which the change in phase
of carbon dioxide or nitrogen from liquid to gas causes rapid
surface freezing. The products are then placed in holding
freezers in which the temperature is maintained between -29° and
-18°C (-20° and 0°F). The waste load associated with freezing is
normally small or insignificant because packaging isolates the
product from contacting any part of the freezing units. IQF
(individual quick-frozen) products, however, are usually frozen
by conveying, in the unpackaged State, through carbon dioxide or
nitrogen freeze tunnels. Product contact with the conveying belt
results in material transfer to the belt, requiring that the
conveying belt be continuously washed. This washing of the belt
can contribute moderately to the raw waste load.
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Packaging
A variety of packaging techniques are used in the poultry further
processing industry. These techniques include the limitation
treated cardboard package, the plastic film sealed under vacuum
or the Cry—O-Vac type of package, the bubble enclosure type
packages used for sliced luncheon meats, and the boxing of
smaller containers or pieces of finished product for shipment.
In some techniques of packaging, a substantial amount of product
handling is involved. This may result in some wasted finished
product. However, the size of the pieces of wasted finished
product are such that there is little reason for it to be washed
to the sewer. Instead, it should be returned for subsequent use
in another processed product or directed to a renderer.
Cleanup of the equipment would be the only time when water would
be generated by the packaging operation. Small quantities of
water are adequate for cleanup of this equipment, and only small
quantities of waste would be generated in cleanup of the
packaging equipment,
ANTICIPATED INDUSTRY GROWTH
The estimated value of the poultry products shipped in 1972 was
$3.7 billion and was expected to rise to $5.0 billion in 1973.
The U. S. Industrial Outlook: 197**7 estimates a six-percent
growth rate for the poultry industry in 1974, However, the
growth of dollar volume in the industry has averaged about 9
percent between 1967 and 1973. Therefore it can be expected that
the dollar growth rate will be somewhere between 6 and 9 percent
over the next several years.
Factors that should contribute to growth can be distinguished
from those that act to restrain this growth. A growing
population and rising family incomes will continue to maintain
consumer demand for poultry products. Per capita consumption of
poultry has risen steadily over the past twenty years, as shown
earlier in this section. In fact, the per capita consumption by
weight of turkey and chicken has risen at an average annual rate
of about 3.5 percent over the period of 1962 to 1972 to a value
of about 52 pounds in 1972. Rapid growth in the volume of
further processed poultry products is anticipated in the coming
years. This is based on the fact that both parents are working
in many families and as a result will tend to purchase more
prepared foods.
The primary restraint to continuing growth of poultry products is
high prices. When poultry prices approach those for red meats,
their sales dip; however, the net effect of this over a period of
time is a lowering in poultry prices. But if all meat prices
remain high, consumers reduce their overall consumption of meat
products by substituting other foods. The direction and degree
of these effects are largely indeterminant at this time.
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SECTION IV
INDUSTRY CATEGORIZATION
CATEGORIZATION
In developing effluent limitations guidelines and limitations of
performance for the poultry processing industry, a judgment was
made as to whether limitations and standards are appropriate for
different segments (subcategories} within the industry. To
identify any such subcategories, the following factors were
considered;
o Type of raw material,
etc. :
broiler, turkey, small game.
o Finished product;
o Processing operations;
o Plant size;
o Plant location and age;
o Waste water characteristics and treatability.
After considering all of these factors, it was concluded that the
poultry processing industry consists of five subcategories. Four
of the subcategories comprise the poultry dressing segment of the
industry, the fifth sufacategqry is for plants that do further
processing only. The subcategories are defined as follows:
1B Chicken processor—a chicken dressing plant that primarily
slaughters broilers; and may also cut up* further process,
and/or render on the same plant site.
2. Turkey processor—a turkey dressing plant that slaughters
turkeys, primarily; and may also cut up and further process
concurrently or seasonally, and/or render on the same
plant site.
3. Fowl processor—a fowl dressing plant that primarily
slaughters light or heavy fowl (mature chickens); and may
also cut up, further process and/or render on the same
plant site. Geese and capon dressing plants are included
in this subcategory.
4C Duck processor—a duck dressing plant that slaughters ducks
primarily; and on the same plant site may also cut up,
further process, and render.
5. Further processing only—a poultry plant that conducts
only furtner processing operations, with any type of
bird, but with no onsite slaughtering.
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The SIC grouping covered in this study includes rabbit and small
game dressing plants. Based on the findings of this study, it is
concluded that such plants need not be considered in effluent
limitations because the volume of their water use excludes them
from the permit program, the plants tend to be small and located
within municipal waste water treatment system access,and there
are very few such plants in operation. Egg plants and soup or
frozen dinner plants are not included in the poultry industry as
defined herein.
A schematic drawing depicting the categorization is presented in
Figure 3. The industry is basically split between plants that
slaughter and those that do not. There is also a reasonable and
significant difference in raw waste load between those that do
slaughter, based strictly on the type of bird that is handled by
the plant.
Those plants that process more than one kind of bird should
generally be classified in the subcategory for the bird that
accounts for the largest volume. If a multi-product plant
handles different types of poultry on a seasonal basis, its
assigned subcategory may vary according to the poultry it is
processing at any given time. Duck processors operating
coincident with a duck feedlot insofar as waste load or treated
discharge is concerned, may be best described as "integrated"
facilities. Provisions for such facilities are discussed in
Section IX,
RATIONALE FOR CATEGORIZATION
Type of Raw Material
The type of raw material used in a poultry dressing plant is an
important factor in substantiating the categorization of the
industry. The term "raw material," in this context, is
synonymous with type of bird or small game animal. The
subcategorization is based on the following types of raw material
as defined:
1. Chicken—-primarily broiler, which is a young chicken usually
between seven and nine weeks old and weighing between
3.5 and 4.25 pounds. Chickens that are not classified as
mature chickens or fowl are also included in this raw
material group.
2, Turkey—a hen or torn turkey of varying age and size.
3. Fowl—a mature chicken larger in average size and older
than broilers; used either as a laying or breeding hen.
Both light (laying) fowl arid heavy (breeding) fowl are
included in this group. Trie small number of geese, capons,
roosters, and stags processed are also included here.
38
-------
POULTRY PROCESSING
INDUSTRY
POULTRY SLAUGHTERING
& DRESSING PLANTS
FURTHER PROCESSING
ONLY
CHICKENS
TURKEYS
FOWL
DUCKS
Figure 3. Categorization of Poultry Processing Industry
-------
5.
Ducks — all those species of birds classified as ducks
usually of domesticated variety raised in feedlots for
commercial marketing.
Smal 1 game — rabbits, pheasants , guineas, squab, and any
other small game animals that are slaughtered tor commercial
use,
The small game portion of this industry represents less than one
percent of industry production.3 The birds in this subcategory
are processed in plants handling other raw materials, which would
contribute the more significant waste load, or in a very few
specialty plants that typically have seasonal operations/ small
waste water volumes, and are discharging into municipal treatment
systems. While a specific subcategory has not been defined, nor
does it appear warranted to do so, data and discussion of these
plants will be included wherever appropriate to amplify the
discussion of poultry processors.
A clear distinction in subcategories based on raw materials is
obtained when the raw waste load basis is weight of BOD5 per unit
weight of LWK, The alternative of BOD5 weight per number of
birds (or animals) killed is less useful because of variations in
bird size which would not be accounted for but which would affect
the results. The poultry processing industry records both the
weight and number of birds processed daily as a matter of routine
accounting*
Finished Product
The finished product of a plant is not a factor in categorization
of the poultry processing industry and thus confirms the proposed
categories. Basically, the poultry industry produces:
o Fresh and frozen whole birds;
o Fresh and frozen parts cut from birds;
o Processed poultry products — frozen, canned, cooked, etc.
The last of the above list includes a myriad of processed
products — other than soups and TV dinners Which are not included
in this industry. They are produced in further processing
operations which are found both in dressing plants and in plants
that further process only.
The primary finished product distinction is made between dressed
birds and processed poultry products. The water use and raw
waste load resulting from production of these two different types
of product differ substantially. However, dressing plants also
may produce processed products. The industry subcategories must
be unique, distinct, and separate from one another. There should
be no overlap nor commonality among the sufccategories. Thus,
while the proposed categorization conceptually reflects
-------
difterences associated wi-tfi finished products, the actual
criterion for categorization is more accurately on in-plant
processing operations, rather than finished product, and the
categorization is thereby further substantiated.
Processing Operations
In-plant processing operation^ are the basic distinction arid
substantiation in categorizing poultry dressing plants as
separate from further processing only plants. The descriptive
title of each group of plants reflects the predominant type of
processing operation in use by the plants. In this context,
predominant means the primary water consumer and waste load
generator. Dressing plants, as indicated previously^
occasionally do include further processing operations. However,
the water use and waste load from the dressing operatipn is
several times that from further processing. In fact, the waste
load from plants combining bo|:h types of operations was found to
be very close to that from plants that only slaughter.
The poultry processing industry makes use of the same terms to
distinguish the different types of processing operations, i.e.,
dressing and further processing. This avoids problems of
definition or interpretation in assigning plants to
subcategories. Thus the categorization based on in-plant
processing operations is established as credible, rational, and
workable. !
Plant Size
Plant size per se is not a factor in categorizing the industry
which substantiates the proposed categorization. There is a wide
range of size of plants in the various subcategories; however,
the range in raw waste load from plants grouped by size was
essentially equal for large and small plants. Waste water volume
and raw waste load per unit of production were found to be
independent of plant size.
Plant Age and Location
Plant age and location do nqt influence poultry processing plants
such as to require consideration in categorization and therefore
substantiate the proposed categorization of the industry. Age as
a potential factor in categqrization at least would have the
advantage of quantitative definition. However, industry
experience and practice precludes even that utilj cy for the age
factor. In-plant processes are continually oeing updated or
improved, so even old buildings may have very c1 crent prpcessing
equipment. Thus, age is difficult, if tot realistically
impossible, to define. In addition, a cursory analysis revealed
no apparent relationship between reported plant age and raw waste
load.
41
-------
The poultry processing industry, as reported previously, tends to
b*i highly concentrated in a few regions of the country. However,
there is no discernible relationship between plant location and
raw wa-^te load.
Thus, plant age and location are not relevant factors in
categorizing the poultry processing industry, which further
confirms the proposed categorization.
Waste water Characteristics and Treatabilitv
Industrial practices within the poultry processing industry are
diverse and produce variable waste loads. It is possible to
develop a rational division of the industry, however, on the
basis of factors which group plants with similar raw waste
characteristics. These raw wastes are amenable to the same
treatment techniques. Thus waste characteristics and
treatability substantiate the categorization.
The waste water characteristic used as the basis in categorizing
the industry is five-day biochemical oxygen demand (BOD5) in
units per 1000 units live weight killed (LWK) : kg BOD5/1000 kg
LWK (Ib BOD5/ 1000 Ib LWK). BOD5 provides the best measure of
plant operation and treatment effectiveness among the waste water
parameters measured, and more data are available for BOD5 than
for any other parameter? Suspended solids data serve to
substantiate the conclusions developed from BOD5,, in categorizing
the industry.
The major plant waste load is organic and biodegradable; BODI5,
which is a measure of oiodegradability, is the best measure of
this type of loading entering a waste stream from a plant.
Furthermore, because biological waste treatment is a biological
process, BOD5 also provides a useful measure of the treatability
of the waste and the effectiveness of the treatment process.
Chemical oxygen demand (COD) measures total organic content and
some inorganic content, COD is a good indicator of change, but
does not relate directly tc biodegradation, and thus does not
indicate the demand on a biological treatment process or on a
stream.
^s described in more detail in Section V, differences exist in
the average BOD5 loads for raw wastes for the five distinct
groupings of poultry processing operations. As defined above,
these groupings (by plant type) are substantiated as
Tabcategories on the basis of waste load. Table 8 presents a
summary of average plant operating parameters for each
subcategory; the parameters include production, water use, and
3OD5 loading in the raw waste.
A number of additional waste load parameters were also
considered. Among these were nitrites and nitrates, Kjeldahl
nitrogen, ammonia, total dissolved solids, and phosphorus. In
each case, data were insufficient to justify categorizing on the
42
-------
Table 8. Production, Waste Water Flow, and Raw Waste Loading
Production
Average, birds /day
Range, birds/day
Number of Plants
in Sample
Average Live Weight
Average, kg/bird
(Ib/bird)
Range, kg/bird
Number of Plants
in Sample
Waste Water Flow
Average, I/bird
(gal/bird)
Range, I/bird
Number of Plants
. in Sample
Raw Waste BODs
Average, kg/kkg LWK
Range, kg/kkg LWK
Number of Plants
in Sample
Chicken
Processors
73,000
15,000 - 220,000
90
1.74
(3.83)
1.45 - 1.97
90
35.4
(9.3)
15.9 - 87.0
88
9.89
3.26 - 26.1 .
60
Turkey
Processors
12,100
2,000 - 30,000
34
8.3
(18.2)
4.1 - 11.4
34
118.2
(31.2)
36.3 - 270.2
34
4.94
0.96 - 9.1
15
Fowl
Processors
34,100
11,900 - 70,000
8
2.3
(5.1)
1.6 - 4.1
8
48.9
(12.9)
11.0 - 159.0
8
15.20
' 11.78 - 23.14.
4
Duck
Processors
6,600
1,900 - 15,000
5
2.9
(6.4)
2.0 - 3.2
5
74.9
(19.8)
71.5 - 78.3
2
7.06
6.59 - 7.52
2
Further
Processing Only
36,700 kg/day FP
(80,500 Ib/day FP)
11,400 - 77,600 kg/day FP
4
12.5 I/kg FP
(1.5 gal/lb FP)
2.92 - 21.34 I/kg FP
4
19.03 kg/kkg FP
16.71 - 22.11 kg/kkg FP
3
-------
basis of the specified parameters; on the other hand, the data on
these parameters helped to verify judgments based upon BOD5.
Judging from biological waste treatment effectiveness and final
effluent limits, waste waters from all plants contain the same
constituents and are amenable to the same biological treatment
techniques. It was anticipated that geographical location, and
hence climate, might affect the treatability of the waste to some
degree. Climate has occasionally influenced the kind of
biological waste treatment used, but has not had an influence on
the ultimate treatability of the waste or the treatment
effectiveness, given careful operation and maintenance. This is
discussed in more detail in Section VII of this document.
Waste water volume and the use of municipal treatment combine as
the primary considerations in deleting rabbit and other small
game dressing plants from effluent limitations guidelines in this
document. Relatively small output and correspondingly small
waste water volume are typical of small game plants. These
plants also are located in urban areas with access to municipal
treatment systems. Thus, there is no need to categorize this
type of plant. Data collected on these plants are reported, but
no effluent limitations guidelines are proposed.
44
-------
SECTION V
WATER USE AND WASTE CHARACTERIZATION
WASTE WATER CHARACTERISTICS
Water is used in large quantities in the poultry processing
industry; it is used to convey byproduct and unwanted materials
from processing areas; to condition, wash, chill, and cook
poultry; as an ingredient in some further processed products; and
to clean equipment and processing areas. The primary waste water
and waste load sources in poultry processing plants are as
follows:
o Killing and bleeding;
o Scalding;
o Defeathering;
o Evi sc erati on;
o Chilling;
o Further Processing:
thaw tanks,
cooking vats,
cooling tanks;
o Rendering plant condensate and condensor water.
Waste waters from poultry processing plants contain organic
matter including grease, suspended solids, inorganic materials
such as phosphates, salt, nitrates and nitrites, and some
coliform count. These materials enter the waste water stream as
meat and fatty tissue, offal, feathers, body fluids from the
birds including blood, losses of materials in process,
preservatives and other product ingredients, and caustic or
alkaline detergents.
Raw Waste Characteristics
The raw waste load for all subcategories of the poultry
processing industry as discussed in the following subsections
includes the treatment effects of in-plant primary treatment in
devices such as catch basins, skimming tanks, and lissolved air
flotation systems. Raw waste is, by definition, that waste water
entering the biological waste treatment system.
The parameters used to characterize the raw wastf are flow, BOD5,
suspended solids (TSS), grease, COD (chemical oxygen demand),
chlorides, phosphorus, Kjeldahl nitrogen, ammonia, nitrites and
nitrates, total volatile solids, and total dissolved solids. As
45
-------
discussed in Section VIT BOD5 is considered to bep in general,
"he most representative measure of the raw waste load. The
parameter used to characterize the size of a plant is the live
weight kill ot birds orff in a further processing only plant,
quantity of processed poultry products produced. All values of
the waste parameters are expressed as kq/kkg of live weight
killed (LWK) or of finished product (FP); this has the same
numerical value as lb/ 1000 lb. At times, some waste components
in effluents are so dilute that concentration becomes the more
significant measure of waste load. In these cases, concentration
is reported as mg/l? which is equivalent to parts per million.
Production quantities are reported in kg/day and waste water flow
is reported in volume (liters and gallons) per bird. Waste water
volume is reported on a per bird rather than weight basis because
process water use is more directly related to the number of birds
than to the weight of the birds; and people in the industry use
the per bird frame of reference in describing water use in their
plants.
The info:onation used to compute production and waste
characteristics data was obtained from questionnaires distributed
to their members by the National Broiler Council, Poultry Science
Association, Poultry and Egg Institute of America, Southeastern
Poultry and Egg Association, Poultry Industry Manufacturer's
Council, Arkansas Poultry Federation, National Turkey Federation,
Pacific Egg and Poultry Processors Association, Mississippi
Poultry Improvement Association, and Alabama Poultry and Egg
Association; from waste water sampling by North Star staff at
fourteen plants; and from data provided by companies in the
industry, by State and municipal pollution control agencies and
sewer boards, by the EPA, and by the U. S, Department of
Agriculture^ Survey questionnaire data were collected on 152
identifiable plants. Data from 83 plants v?ere adequate for use
in categorization and in characterization of the raw waste and
waste treatment practices.. Generally9 information found in the
opan literature was not detailed enough to be included in the
data base.
A summary table of production data, waste water volume, and raw
waste characteristics is presented for each of the five
subcategories in the following subsections. The subcategories of
the industry are:
1. Chicken processor;
2. Turkey processor;
3«, Fowl processor;
4. Duck processor;
5Q Further processing only.
These subcategories are defined in detail in Section IV.
46
-------
processors
These plants typically slaughter bvciler-size chickens and
package them as ready-to-coos in an ice pack or a cold pack with
dry ice. The North Star data ijiol'icJea responses from 92 chicken
dressing plants, which accout-t 'f-.jr about 63 percent of the total
live weight kill in the country. The largest percentage of these
plants reportedly slaughters <*iid cuts up some portion of their
production. The chicken ^recessing plants are divided in the
sample as follows:
Slaughter only — 21 percent
Slaughter plus cut-up — 43 percent
Slaughter plus further process — 0 percent
Slaughter plus render — 5 percent
Slaughter plus cut-up and render-- ^S peroent;
The raw waste characteristics rep^r^ed in Table 9 are averages of
data from all of these types of eiiiei:xn ^rocessin? plJ.nKs?. The
raw waste data includes plants with aVi. combinations of
operations in the chicken processing su< category,
The principle sources of waste watier in thiF.sc pl«ntP are the
feather and offal flow- away systems, which are part of the
typical defeathering and evisceration oper3tions. One of the
recent innovations introduced into poultry processing plarvtp is a
dry offal handling system. Two chicken processing plants in the
North star sample reported this type of system, and both plants
reported lower than average waste water volumes* '
Various water circulation .«vF+ei.i* 3iv also j « yse by processing
plants, including flow-away systems wat«r reoircnlation to the
feather flume, chiller overflow water to Li.-c feather flume, and
slaughtering plant raw waste water u:se in rendering plant
barometric condensers. The us« of these options bonds to
contribute to the uniformity of t.!, « raw v^«st*» load for the
various types of plants in this subcategory.
Turkey Processors
Most turkey processing plants slaughter turkeys 8 to 10 Months of
the year. Host of these plants also include further processing
operations, which may be used up to 12 r-ionths per year. Like the
chicken processing plants, the waste water comes primarily from
the feather and offal flow-away systems. During that -time- of the
year of further processing only, frozen t.irr.Veys are nsep as the
raw material and the water used in the thawing tenkc contributes
the largest volume of waste wafers* The data on the raw waste
characteristics of turkey plants Are presented in T^ble 10.
47
-------
Table 9. Raw Waste Characteristics of Chicken Processors
Parameter
Production
Average Live
Weight
Waste Water
Flow
BOD5
SS
Grease
COD
TVS
TDS
TKN
NH3
NO 3
N02
Cl
TP
Units
birds/day
kg/bird
(Ib/bird)
I/bird
(gal/bird)
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
Average
73,000
1.74
(3.83)
34.4
(9.3)
9-89
6.91
4.21
19.70
13.31
11-67
1.84
0,23
0.0078
0.0069
1.97
0.39
Range
15,000 - 220,000
1.45 - 1.97
15.9 - 87.0
3.26 - 19.86
0.13 - 22.09
0.12 - 14.03
2.04 - 56.81
3.48 - 47.17
3.52 - 45.8
0.15 - 12.16
0.005 - 0.73
0.0 - 0.14
0.0 - 0.037
0.006 - 9.16
0.054 - 2.46
Number of
Observations
90
90
88
60
53
39
31
23
23
15
19
12
14
12
22
48
-------
Table 10. Raw Waste Characteristics of Turkey Processors
Parameter
Production
Average Live
Weight
Waste Water
Flow
BOD5
SS
Grease
COD
TVS
TDS
TKN
NH3
N03
NO 2
Cl
TP
Units
birds/ day
kg /bird
(Ib/bird)
I/bird
(gal/bird)
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
Average
12,100
8,3
(18.2)
llg.2
(31.2)
4.94
3.17
0.89
7.39
8.36
13.53
0.94
0.15
0.037
0.0013
2.49
0.098
Range
2,000 - 20,000
4.1 - 11.4
36.3 - 270.2
0.96 - 9.1
0.57 - 10.89
0.34 - 1.81
3.07 - 10.95
2.20 - 19.16
1.51 - 38.45
0.38 - 1.89
0.064 - 0.37
0.005 - 0.092
0.001 - 0.002
0.38 - 5.41
0.034 - 0.18
Number of
Observations
34
34
34
15
13
10
5
6
5
5
5
3
3
4
4
49
-------
One turkey plant in the North Star sample of the industry
rt:ported having a dry offal handling system. No raw waste data
were reported for this plant, however, and the data on waste
water volume did not indicate any significant savings.
Fowl Processors
Fowl processing plants are basically similar to chicken
processing plants except for the larger average size of the
birds. Fowl are usually processed into the further processed
types of products either onsite or in a plant at another
location. The slaughtering and eviscerating of fowl are the
primary sources of the waste water and the raw waste load. The
feather and offal flow-away systems are likewise the major waste
water sources. In spite of the higher average weight, the
average raw waste load of BOD5 per unit LWK is significantly
higher than that for the chicken plants. The data on typical or
average production, water use, and raw waste characteristics are
presented in Table 11.
Duck Processors
Duck feedlots are located on the same plant site as duck
processing plants in all but one plant in the industry, according
to the data collected by North Star. This was confirmed by
several duck growers and processors. The water flow and waste
load from a combined processing plant and feedlot is
substantially greater than that from a processing plant alone.
However, tie processing plant will be dealt with as a single
source in tnis report and the additional load from the feedlot
will of course be considered and accounted for.
The slaughtering and evisceration operations in duck processing
are basically the same as that for other poultry, with the
addition of wax dipping for pinfeather removal. The feather and
offal flow-away systems are again the major sources of waste
water and raw waste load. The waste water and waste load data
presented in Table 12 for two plants represent the processing
plant waste load only; feedlot waste water and loading are not
included, as described above.
Further Procg ssinq Only
Plants that further process only (do no slaughtering) prepare
finished poultry products primarily from chickens, fowl, and
turkeys. Cooking is involved in all further processing plants,
as defined in this study. These plants remove specific parts of
the birds, such as wings and legs, and then remove the remaining
meat from the skeletal structure of the birds. Cooking may
precede or follow this cutting operation. The meat is used in
large pieces or reduced in size in special equipment. Various
ingredients are mixed with the poultry meat and the numerous
50
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Table 11. Raw Waste Characteristics of Fowl Processors
i'arameter
Production
Average Live
Weight
Waste Water
Flow
BOD 5
SS
Grease
COD
TVS
TDS
TKN
NH3
N03
N02
Cl
TP
Units
birds /day
kg /bird
(lb/bird)
I/bird
(gal/b±rd)
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
Average
34,100
2.3
(5.1)
48.9
(12.9)
15.20
10.09
2.32
41.39
18.40
24.88
0.28
0.10
i 0.0044
0-00053
3.99
0.29
Range
11,900 - 70,000
1.6 - 4.1
11.0 - 159-0
11.78 - 23.14
6.11 - 14.94
0.72 - 3.32
24.26 - 58.52
13.10 - 23.71
9.14 - 40.62
—
—
—
—
0.27 - 0.31
Number of
Observations
8
8
8
4
4
3
2
2
2
1
1
1
1
1
2
-------
Table 12. Raw Waste Characteristics of Duck Processors
Parameter
Production
Average Live
Weight
Waste Water
Flow
BOD5
SS
Grease
COD
TVS
TDS
TKN
NH3
N03
N02
Cl
TP
Units
birds /day
kg /bird
(Ib/bird)
I/bird
(gal/bird)
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
kg/kkg LWK
Average
6,600
2.9
(6.4)
74.9
(19.8)
7.06
4.36
1.86
14.08
7.08
8.30
1.40
0.79
0.030
0.0097
1.44
0.084
Range
1,900 - 15,000
2.0 - 3.2
71.5 - 78.3
6.59 - 7.52
3.47 - 5.24
0.66 - 3.05
13.57 - 14.58
6.69 - 7.48
3.97 - 12.62
0.80 - 2.00
0.062 - 1.52
0.018 - 0.043
0.0014 - 0.018
0.78 - 2.11
0.073 - 0.096
Number of
Observations
5
5
2
2
2
2
2
2
2
2
2
2
2
2
2
52
-------
types of finished products are formed, cooked, packaged, and
usually frozen.
The waste water and waste load originates primarily in cleanup of
further processing equipment and plant facilities. The relative
quantities of water and waste load are substantially less in
these plants than in slaughtering plants. The data are
presented in Table 13 on production, waste water volume, and raw
waste characteristics for plants that further process only.
The USDA reports the number of plants in the industry that
further process only is 288,2 tut the 19,62. Census of
Manufacturers indicates only 18 plants fitting that description.3
Based on the response to the questionnaires and an extensive
inquiry of the industry, the number of further processing onl•'
plants was judged to be 18 to 20. The USDA figures undoubtedly
include plants that are not part of the designated SIC codes for
this study.
Discussion of Raw Wastes
The full tabulation of the raw waste characteristics for each
subcategory are presented in the preceding tables. Figures U and
5 present a graphic comparison of average waste water volume and
raw waste loads for the five subpategories. The raw waste
parameters of BOD.5, suspended solids, and grease, reported as
kg/kkg LWK, were used in the comparison in Figure 5, and waste
water volume per bird was the basis for Figure 4. The basis for
the data for further processing only plants was output of
finished product rather than LWK. The relatively high raw waste
loadings for further processing only plants were presumably
caused, in part, by the lack of any in-plant primary treatment in
three of the four plants.
All four plants in the sample reported using municipal treatment.
The differences in the average waste load are apparent. The
averages of course represent ranges of values, as reported in the
tables of data, and there is overlap in these ranges. The
average value of the waste parameters for each subcategory
includes those plants that also cut-up, further process, and/pr
render on the same plant site. Table 14 lists the number of
plants in each subcategory in the sample according to what
operations are conducted in the pl^nt. The cutting operation is
conducted primarily in chicken plants so it is not reported for
the other subcategories.
The raw waste load and related quantities of farther processed
products and rendering raw materials were analyz' 1 to determine
whether or not there was any relationship betwf n waste load and
further processing or rendering. There wa no consistent
positive pattern between increasing volumes of rurther processing
or rendering with a corresponding increase in raw waste load. In
fact, most of the plants with onsite rendering had lower than
average raw waste loads, which may simply indicate a more
53
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Table 13. Raw Waste Characteristics for Further Processing Only
Parameter
Production
Waste Water
Flow
BOD5
SS
Grease
COD
TVS
TDS
TKN
NH3
N03
N02
Cl
TP
Units
kg /day FP
(Ib/day FP)
I/kg FP
(gal/lb FP)
kg/kkg FP
kg/kkg FP
kg/kkg FP
kg/kkg FP
kg/kkg FP
kg/kkg FP
kg/kkg FP
kg/kkg FP
kg/kkg FP
kg/kkg FP
kg/kkg FP
kg/kkg FP
Average
36,700
(80,500)
12.5
(1.50)
19.03
9.06
6.36
40.63
16.16
30.01
2.04
0.13
0.018
0.0019
2.25
0.12
Range
11,400 - 77,600
2.92 - 21.34
16.71 - 22.11
2.92 - 14.64
4.83 - 7.89
—
11.69 - 20.64
—
—
6.095 - 0.16
—
—
1.03 - 3.47
— -
Number of
Observations
4
4
3
3
3
1
2
1
1
2
1
1
1
1
-------
w
CC
UJ
H
-J
_l
O
>
cc
UJ
I-
120
115
110
105
100
95
90
85
80
70
55
50
40
35
30
25
20
15
10
5
0
CHICKEN
TURKEY
FOWL
Figure 4. Average Waste Water Volume Generated Per Bird in
Processing Plants by Subcategory
[Further Processing Only is 12.5 liters/kg FP (1.5 gal/lb)]
-------
Ln
.
, ;" h
•— *
s .,,
-j *-.* f
3) •
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^yC
^/\
fx i
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O^
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-« — 30D5
- — SUS.S.DUDS
-• GREASE
° • CHICKEN TURKEY FOWL DUCK ' FURTHER
paocsssjMS
ONLY
(DATA PTS -
Figure 5. Average Raw Waste Loading of Waste Water
From- PlriTits 'in Each Suhcattgory
-------
Table 14.
The Number of Plants in the Questionnaire
Sample Reporting the Use of Various
Manufacturing Processes Within Each
Subcategory
Manufacturing Process
Slaughter only
Slaughter plus cutting
Slaughter plus rendering
Slaughter plus further
processing
Slaughter plus cutting
plus rendering
Total
Chicken
19
38
5
7
21
90
Turkey
21
—
2
11
34
Fowl
4
—
2
2
8
Duck
4
1
—
—
5
57
-------
concerted effort at collecting and retaining byproducts or better
byproduct materials handling situations in those plants. There
is some indication of increased waste load with ir^raased output
of further processed products in poultry slaughtering plants.
However? it is not statistically significant. Therefore, the raw
waste data are reported for all plants in each subcategory sample
and are included in the singular averages for the subcategori^s.
These averages thus include the plants tbct further process or
render in addition to slaughtering,
A regression analysis of the raw BOD5 loading of chicken or
turkey plants that slaughter and further process as a function of
total output of further processing products yielded an es-timate
of the increase in raw waste BOD5 of 0.11 kg/kkg LWK per 1000 kg
FP (0.05 lb/1000 113 LWK increase in BOD5 per 1000 Ib FP) . There
are four plants in the sample producing U5,000 kg (100,000 Ib) FP
or more in processing plants. At this level of production of
further processed products, the results of the regression
analysis suggests that the raw BODji waste load would be 5.0
kg/k&g LN'K (5.0 lb/1000 Ib LWK) higher than if the plant did no
further processing, and only slaughtered. This result is not
statistically verifiable because of the wide scatter of the data,
but the information can be incorporated into the proposed
limitations as discussed in Sections IX through XI.
Data on the BOD5 loading of the raw waste water for each month
during one or two years were obtained from eight plants. The
analysis of these data revealed that in four of the plants the
raw waste v/ater loading of BOD?5 tended to be more stable and
consistent during the months of April through July. A more
persistent pattern of variability during the latter months of the
year was found in the data from these plants. Generally
speakingr a waste loading range equal to two times the typical
low value of BOD5 would include about 90 percent of the data
points for any given plant throughout the year. There also were
two plants with very consistent raw waste loading during the
entire year, varying less than 30 percent above the average in
one case.
A statistical test was used to determine the existence of mutual
relationships between the various pollutant parameters, e.g.,
BOD5P suspended solids, grease, and the various nutrient sources.
Correlation analysis determines if increases in the quantity of
one pollutant in a waste water system are accompanied by
corresponding increases or decreases of another pollutant. There
is a considerable amount of data on broiler plants in the North
Star sample; however, the scattering of the data resulted in a
finding of no significant correlation or strong relationship
between any of the pollutant parameters. The data on turkey
plants are far less extensive, however a significant relationship
was found between BOD5 and suspended solids in the raw waste.
This relationship is one of the expected outcomes of this
analysis; that as one increases the other also increases
correspondingly. It is wrong to conclude, however, that there is
58
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a cause and effect relationship between highly correlated
variables such as these pollutant parameters.
Process Waste Water Flow Diagrams
The origin and estimate of relative process waste water quantity
is indicated for the two general poultry production processes--
dressing and further processing—in Figures 6 and 7, The waste
water from cleanup, which is usually the largest and strongest
waste load from further processing operations, is not indicated
in these figures because cleanup involves virtually the entire
processing plant, with the exception of the freezer areas, and
the cleanup waste water follows the same path through the plant
as a process waste water.
The sources and relative quantities differ for each process.
However, byproduct recovery with rotary or vibrating screens
followed by a catch basin is typical of dressing plants. The
upstream screens are unnecessary in further processing only
plants; however, a catch basin is always desirable. Screens were
also installed downstream from the catch basin or on a
recirculating waste water stream from the catch basin in a few
plants.
The other options available to the industry are also indicated in
these figures. The plant utilities waste water may by-pass
biological treatment. The dilution and increased volume of waste
water only serves to inhibit biological treatment effectiveness.
The sanitary sewage always enters the waste water downstream from
the catch basin.
Liquid waste and wash water from the truck holding and unloading
areas is also handled in different ways by processing plants in
the industry. Most segregate the entire waste system while
others combine the waste water downstream from the in-plant catch
basin. Also, most companies do not wash down the live poultry
trucks on the plant site.
WATER USE/WASTE LOAD RELATIONSHIPS
Increased water use is usually associated with increased raw
waste loading from plants throughout the meat industry. This is
generally true for poultry processing plants also, and has been
demonstrated in experimental programs in poultry plants.9
However, this conclusion is not substantiated as statistically
significant with the data from the different plants in the
sample. There are a small number of poultry plants with high
water use and low waste load, and vice versa, ana these plants
disturb the rigorous statistical test of signifjcance. However,
there is a trend that increased water use will generally result
in higher raw waste loads, as measured by BODjj.
59
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PROCESSES
PRODUCT FLOW I BY-PRODUCT FLQW
WASTE
LIQUID
SOLID
BIRDS
ALTERNATE SOLIDS I FLOW
AS SOLIDS I WASTE
(INCLUDES DRY I CLEANUP)
1NEWBLE I __
RENDERING
J
FRESH &
FROZEN
POULTRY
SLUDGE |
MATERIALS FLOW—
PROCESS WATER
WASTE WATER
IOI.UL/UC
|—— 1
(SECONDARY | | SOLID j
I TREATMENT • I WASTE
I PLANT I I DISPOSAL
I 1 I I
L_ DISCHARGE TO
RECEIVING WATERS
Fi gure 6.
Product and Waste jnfater Flow for Typical
Poultry Processing Plants
60
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PROCESS AND MATERIAL FLOW
WASTER WATER,
RELATIVE FLOW*
i r
RECEIVING
AND
STORAGE
SM-PER ODIC
CUT-UP
OPERATIONS
SM-PERIODIC
MED-LGE
SM-MED PERIODIC
DICING.
GRINDING
CHOPPING
BATTER AND
BREADING
MIXING,
BLENDING
SM - IVIED PERIODIC
SM - MED
MED -LGE
MED -LGE
PREPARATION
FREEZING &
PACKAGING
VSM PERIODIC
MATERIAL OR
PRODUCT FLOW
COLD
STORAGE
WASTE WATER
*VSM -VERY SMALL
SM - SMALL
MED -MEDIUM
LGE - LARGE
TO SECONDARY TREATMENT
AND DISCHARGE OR CITY SEWER
Figure 7. Process and Waste Water Flow For Further Processing
61
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The trend lines of waste load versus waste water volume for
chicken and turkey plants are presented in Figure 8. An
interpretation of these trend lines suggests that in chicken
plants, a 25-percent reduction in water use from, say, 45 to 35
liters per bird (11 to 9 gallons per bird) would result in a 15-
percent reduction in the raw BODji waste load. In turkey plants,
a 39-percent reduction in water use would reduce the BOD5 loading
by about 15 percent in the raw waste. Each plant probably has
its own typical and unique water use/waste load relationship,
although it may differ somewhat from Figure 8.
Basically, low water use and the correspondingly low waste load
require attentive and concerned management attitudes regarding
in-plant water use. Without the active support and intervention
of management, water management programs do not succeed; with it,
water use can be reduced and the raw waste load will decrease.
Waste water treatment systems operate more effectively with
reduced hydraulic and waste loads.
SOURCES OF HASTE WATER AND WASTE LOAD
Killing and Bleeding
The strongest single pollutant in a poultry dressing plant is
blood. Chicken blood has an approximate BOD5 of 92,000 mg/1 and
1,000 chickens may generate 7,9 kg (17.4 lb) of BODji in
recoverabls blood.9 Poultry are manually or mechanically killed
by an exterior cut on the neck; ducks may be killed by inserting
a knife rinto the mouth and down the throat, thus avoiding the
exterior cut. The common practice is to electrically stun the
birds just before killing. Occasionally, stunning follows the
kill, and in a few plants other measures are employed such as
ultraviolet lighting instead of an electric shock.
The birds are bled while they hang from a moving conveyor. The
conveyor is confined to a single rbpm or space usually called the
blood tunne.L, which is equipped with some means of collecting and
handling the blood. A couple of plants have installed a raised
metal trough to collect and retain the blood as the birds were
convened along the length of it. This trough is installed and
operated primarily as a byproduct recovery device. It is dry
cleaned with a squeegee several times during the day and the
blood flows through a vacuum line to a holding tank.
There are three factors that control the quantity of blood that
enters the waste water stream: time in the blood tunnel, body
movement of the birds in the tunnel, and handling and cleanup
procedures for the blood. The residence time of an animal in the
blood tunned is fairly well standardized across the industry
today. However, those few plants that were found to maintain
shorter bleed times demonstrated unusually high raw waste loads.
This presumably results from latger volumes of residual blood
draining after removal of the animal from the blood tunnel.
62
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a-
20
18
16
14
D)
*& 12
ih
§ 10
DO
LU
w 8
5
I 6
cc
4
WASTE WATER VOLUME FOR CHICKEN PLANTS, GALS/BIRD
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
CHICKEN
PLANT
DATA
/I TURKEY
M PLANT
I DATA
5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
WASTE WATER VOLUME FOR TURKEY PLANTS, GALS/BIRD
Figure 8. Approximate Relationship Between Raw Waste Loading of BOD5 and
Waste Water Volume Per Bird for Chicken and Turkey Plants
-------
Body movement of the birds as they bleed may scatter the blood
onto the feathers of adjacent birds and onto the conveyor and the
walls of the blood tunnel. The blood on the feathers will be
washed off in the scalder and into the waste water. The blood on
the conveyor and walls will be washed off into the sewer during
cleanup.,
Handling and cleanup procedures can contribute significantly to
the quantity of blood that is allowed to enter the sewer. The
metal trough described previously was a particularly effective
mechanism for confining and handling blood. No plants were found
to dump i:he blood into the sewer. It is a valuable byproduct and
is handled as such. However, large bleeding spaces and heavy
reliance on water washing in preference to dry cleanup add
significantly to the waste load,
Scalding
The scalding operation loosens the body feathers of poultry. It
is also the first washing of the carcasses, thus the scalder
effluent will contain dirtff feathers, fclood, manure, and some
dissolved fats and greases. The TJSDA requires an overflow and
freshwater makeup of one-quarter gallon per bird. The BOD5 in a
scalder has been measured at 490 mg/1 and 1,182 mg/1, suspended
solids at U73 and 687 mg/1, and grease at 350 mg/1.9
The scalder overflow is usually used to augment the feather flow
away water and is dumped directly into the feather flume. The
scalder water is maintained at temperatures between 53° and 63°C
(128° and 1U5°F); however, the flow is not sufficient to raise
the waste water temperature much above 21°C (70°F). The primary
impact of ttie scalder occurs at the end of the operating day when
it is dumped and cleaned. The dumping generates a potential
shock load i;o the waste water handling system. Cleanup requires
washing the dirt, blood, and other accumulated debris from the
scalder and into the sewer again in relative surges of water.
Defeathering
Large quantities of water are used to move feathers from the
defeathering operation to byproduct recovery in flow-away
systems. This water use has been estimated to total 10.6 liters
(2,8 gallons) per bird in a chicken plant, including 50-percent
freshwater c.nd 50 percent reused or recirculated water.
Defeathering water will contain dirt and blood and feathers.
Screened offal flume water also is sometimes reused in feather
flumes. The BODjj in a feather flume was reported to be 590 mg/1,
the suspended solids 512 mg/1, and grease 120 mg/1.9 The North
Star waste water sampling program obtained these results for
feather flume waters: 565 mg/1 BODji and 330 mg/1 suspended
solids. The feather flume was also reported to be a high source
of ammonia,, on the order of seven times higher than the offal
flume**°
-------
A carcass washer follows the defeather process. The water use
rate in this washer was found to be 140 liters/min (37 gpm) and
the BOD5 of the waste water was reported to be 108 mg/1, with
suspended solids of 81 mg/1 and grease at 150 mg/1,9
Cleanup of the defeathering area occurs periodically during the
day and at the end of the day, usually involving the use of large
quantities of water to wash the feathers into the flume. The
water use was found to be 130 liters/min (34 gpm) during this
intermittent cleaning at one plant.9
Evisceration
The evisceration process generates a large volume of waste water.
Carcass and giblet washing, worker hand washers, side-pan washers
in the viscera trough, and viscera flow-away water all contribute
to the total evisceration waste water which has been estimated to
be 23 liters (6.1 gallons) per bird.9
In the evisceration process, the bird is opened up, the viscera
are extracted from the peritoneal cavity; after inspection, the
giblets are removed from the viscera, then trimmed and washed;
and the inedible viscera is dropped into the viscera trough.
Heads and feet are removed from the birds and dropped into the
feather or offal flumes. The lungs are usually vacuumed to a
holding tank, and the windpipe and extraneous tissue are removed
and dropped into the trough. A carcass washer is located at the
end of the evisceration line to wash both the inside and outside
of the birds. In one plant, this washer used 380 liters/min (100
gpm) or about 3 liters (0.8 gallons) per bird.9
Much of the eviscerating process is done by hand. The workers
and inspector are required to use hand washers to avoid cross-
contamination. The quantity of water used in hand washing
appears to be discretionary.
The waste water from evisceration will contain tissue and fat
solids, grit, grease, blood, and bacteria from the intestinal
tract, A BODj> of 230 mg/1 and suspended solids of 302 mg/1 are
reported in the literature.9 This BOD5 concentration is
equivalent to about 5.4 kg (12 Ib) per 1,000 broilers. North
Star sampled an offal flume downstream from the offal screening
equipment and found a BOD5 of 365 in 7/1 and suspended solids of
196 .Tig/1.
Cleanup of the evisceration line also consumes a significant
volume of water, although the waste loading i~5 comparatively
light. The equipment is washed down at every break and during
the lunch hour, and then it is thoroughly cleaned at the end of
the day. The cleanup waste load consists primarily of meat and
fat particles left clinging to the equipment, the grease coating
that accumulates on exposed surfaces, and residual solids that
were not conveyed by the flow-away system in the trough.
65
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Chilling
The temperature of the carcass and giblets of poultry must be
quick3,y reduced to 4°C (40°F) after evisceration. The carcasses
are usually cooled by immersion in two-stage chillers filled with
ice-water„ The USDA requires that 1.9 liters (0.5 gal) of
freshwater nust be added per bird. An overflow, equal to the
make-up; plus dragout losses results in about 2.8 liters (0.75
gal) per bird of waste water into the sewer, frequently via the
offal flume. Giblets are cooled in smaller but comparable
equipment or in heat exchangers which prevent contact between the
cooling water and the giblets.
The waste water from carcass chillers was found to be 272
liters>'ttin (72 gpmj for a plant processing 70,000 birds per day
and the giblet chillers used 17 liters/min (U.5 gpm). * The raw
waste load of BOD5 in giblet chilling water was reported to be
2,357 mg/lt, with suspended solids at 976 mg/1 and grease at 1,320
mg/1.9 The exceptionally high concentrations may result from the
low water volume. The carcass chiller waste load was reported to
be i*<&0 mg/1 and 320 mg/1 of BODji from the first and second
chillers,, respectively. The suspended solids were found to be
250 mg/J. and 180 mg/1 and grease was 800 mg/1 and 250 mg/1 for
the waste water from the first and second chillers, A North Star
sample ol chiller water in a turkey plant was analyzed at 180
mg/1 BOD5 and 77 mg/1 for suspended solids.
Cleanup of the chilling equipment requires dumping the water at
the end of each day, which may overload the waste water handling
system if dumped over a short period of time. The equipment
acquires .1 conspicuous covering of grease which is washed off
during cleanup. This material is wasted to the sewer. Meat and
fat particles and blood accumulate in the chiller during the
operating day. Any materials remaining in the chiller after it
has been clumped are washed out during cleanup,
Byproduct Recovery
The screening equipment for the feather and offal flumes and the
byproduct material handling equipment comprise the byproduct
recovery area. No appreciable amount of waste water is generated
in byproduct recovery other than the screen washing water used
during the operating day and the water from cleanup. The water
retained by the feathers and offal will drain through the
materials handling equipment and from the offal truck which
receives and holds these byproducts throughout the day. This
drainage enters the waste water stream directly,
The waste load is not generated per se, in byproduct recovery,
but results from losses due to inefficiency or ineffectiveness of
the recovery equipment. Thus? although the waste water quantity
generated in byproduct recovery is small, the waste load may be
substantial, depending on the screening effectiveness in removing
66
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offal and feathers and the manner in which the blood is handled
on the offal truck. If blood is simply dumped on the feathers or
the offal, it will 3rain through and add significantly to the
waste load.
Further Processing
Further processing operations use water to thaw frozen raw
materials, e.g., turkeys, to cook poultry and finished products,
to cool the freshly cooked birds and products, and to clean the
plant and equipment.
When frozen birds are used as a source of raw materials, further
processing operations thaw the birds in chillers—otherwise used
to chill freshly eviscerated birds—or in large portable vats
filled with water and agitated by bubbling air through the water.
The frozen birds are thawed while wrapped in a protective package
such as Cry-O-Vac, or are unwrapped prior to thawing. If the
former is used, the water does not contact the birds directly as
it would in the latter case, and the waste load from thawing
would be relatively little. The direct contact between the birds
and water results in a significant waste load in the thawing
waters. These waters are dumped after each batch of birds is
thawed, with the resulting water and waste load entering the
sewer.
Birds and finished products are frequently cooked by immersion in
steam-jacketed vats of hot water. Baskets of whole birds and
parts or racks of products are immersed in the hot water, which
includes spices and preservatives. The grease from cooking is
continuously collected as a high-value edible fat. The total
volume of waste water is relatively small. It amounted to
approximately 0.1 liters (p.03 gallons) per processed bird in one
plant sampled by North Star. The waste load in one sample of the
cooking waters at the same plant was found to be 4,665 mg/1 BOD5,
1,068 mg/1 suspended solids, and 514 mg/1 grease. These vats are
dumped at the end of each processing day and thoroughly cleaned.
While the waste water volume is not great, the waste load is a
significant one.
Many of the freshly cooked products are immediately cooled by
immersion in cold water. Cooling tanks are similar to the
cooking vats, but without a steam jacket. A cold water makeup
and subsequent overflow is required at between 2 and 4 liters per
minute (0.5 and 1 gpm). The cooling water is fresh* clear water
without any processing additives. However, the wat^r in the tank
comes into immediate contact with the hot produc .s and chicken
parts. These cooked products and chicken p rts have a
substantial surface coating of various pollutants such as grease,
cooking water and broth, and spices and preserv ^tives. Most of
these materials plus seme meat, fat, and skin tissue are washed
into the cooling water. The overflow from the cooling tank flows
into the sewer during the operating day. At the end of the day,
the tank is emptied and cleaned. The volume of water discharged
67
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at this time is relatively small; however, the accumulated solids
and other pollutants are dumped, simultaneously generating a
considerable waste load.
Rendering Plant condensate and Condenser Water
Some poultry processing plants have onsite rendering plants to
produce feed grade materials from the byproducts (feathers,
offalp blood, etc.) of the processing plant. A small number of
plants have sufficient rendering capacity to bring in byproducts
from other dressing plants.
Condensate from cooking and drying the byproducts is a high-
strength waste. A previous study of the independent rendering
industry provided data indicating BOD5 concentrations of 1,235 to
1,350 mg/1 in undiluted condensate from poultry byproduct
rendering. The suspended solids and grease are inconsequential
in the condensate. Undiluted condensate would occur only in a
closed condenser such as air or shell-and-tube condensers.
Barometric condensers will dilute the condensate and lower the
concentration, but the total loading of the rendering raw waste
is unaffected.
Spills from the rendering equipment and materials handling will
contribute to the raw waste load. Cleanup of these spills will
add to the waste water volume.
The waste w;\ter generated in onsite rendering systems amounts to
about 15,800 1/kkg raw material (1,900 gal per 1000 lb RM) based
on the data collected by North Star. For chickens, this waste
water flow is equivalent to approximately 7.2 liters (1.9
gallons) per bird, and for turkeys it is 27.6 liters (7.3
gallons) per bird, or 20 and 23 percent of the average flow from
chicken and turkey dressing plants, respectively.
68
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SECTION VI
SELECTION OF POLLUTANT PARAMETERS
SELECTED PARAMETERS
Based on a review of the Cofps of Engineers1 Permit Applications
from poultry processing plants; previous studies on similar waste
waters such as from the meat packing, meat processing, and
independent rendering plants; industry data; questionnaire data;
and data obtained from sampling plant waste waters during this
study, the following chemical, physical, and biological
constituents constitute pollutants as defined in the Act.
BOD5 (5-day, 20°C biochemical oxygen demand)
COD (chemical oxygen demand)
Suspended solids (TSS)
Total dissolved solids (TDS)
Total volatile solids (TVS)
Grease
Ammonia nitrogen
Kjeldahl nitrogen
Nitrates and nitrites
Phosphorus
Chloride
Bacteriological counts (total and fecal coliform)
PH
Temperature
On the basis of all evidence reviewed, there do not exist any
purely hazardous pollutants (such as heavy metals or pesticides)
in the waste discharge from poultry processing plants.
RATIONALE FOR SELECTION OF IDENTIFIED PARAMETERS
5-Pay Biochemical Oxygen Demand (BODS)
This parameter is an important measure of the oxy-jen consumed by
microorganisms in the aerobic decomposition of the wastes at 20°C
over a five-day period. More simply, it is an indirect measure
of the biodegradability of the organic pollutants in the waste.
69
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^ can be related to the depletion of oxygen in the receiving
stream or to the requirements for the waste treatment. Values of
BOD5 range from 100 to 1500 mg/1 in the raw waste, although
typical values range from 200 to 700 mg/1.
If the BOD^ of the final effluent of a poultry processing plant
into a receiving body is too high, it will reduce the dissolved
oxygen level Ln that stream to below a level that will sustain
most fish life; i.e., below about 4 mg/1. Many States currently
restrict the BOD5 effluents to below 20 mg/1 if the stream is
small in comparison with the flow of the effluent. A limitation
of 200 to 300 mg/1 of BOD5 is often applied for discharge to a
municipal sewer, and surcharge rates often apply if the BOD5 is
above the designated limit. BOD^ is included in the effluent
limitations recommended because its discharge to a stream is
harmful to aquatic life since it depletes the oxygen supply.
A 20-day biochemical oxygen demand (BOD20), sometimes called
"ultimate-1 BOD, is usually a better measure of the waste load
than BOD5>. However, the test for BOD20 requires 20 days to run,
so it is an impractical measure for most purposes.
Correlation analysis of the data revealed a high positive
correlation between BOD5 and suspended solids, chemical oxygen
demand, total volatile solids, Kjeldahl nitrogen, and ammonia
nitrogen on both the raw and final effluent. Such correlations
are useful in identifying contributing factors in the waste load
and relating known changes in the contaminant to predicted
changes by another.
Biochemical oxygen demand (BOD) is a measure of the oxygen
consuming capabilities of organic matter. The BOD does not in
itself cause direct harm to a water system, but it does exert an
indirect effect by depressing the oxygen content of the water.
Sewage and other organic effluents during their processes of
decomposition exert a BOD, which can have a catastrophic effect
on the ecosystem by depleting the oxygen supply. Conditions are
reached frequently where all of the oxygen is used and the
continuing decay process causes the production of noxious gases
such as hydrogen sulfide and methane. Water with a high BOD
indicates the presence of decomposing organic matter and
subsequent high bacterial counts that degrade its quality and
potential uses.
Dissolved oxygen (DO) is a water quality constituent that, in
appropriate concentrations, is essential not only to keep
organisms living but also to sustain species reproduction, vigor,
and the development of populations. Organisms undergo stress at
reduced DO concentrations that make them less competitive and
less able to sustain theit- species within the aquatic
environment. For example, reduced DO concentrations have been
shown to interfere with fish population through delayed hatching
of eggs, reduced size and vigor of embryos, production of
deformities in young, interference with food digestion.
70
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acceleration of blood clotting, decreased tolerance to certain
toxicants, reduced food efficiency and growth rate, and reduced
maximum sustained swimming speed. Fish food organisms are
likewise affected adversely in conditions with suppressed DO.
Since all aerobic aquatic organisms need a certain amount of
oxygen, the consequences of total lack of dissolved oxygen flue to
a high BOD can kill all inhabitants of the affected area.
If a high BOD is present, the quality of the water is usually
visually degraded by the presence of decomposing materials and
algae blooms, due to the uptake of degraded materials that form
the foodstuffs of the algal populations.
Chemical Oxygen Demand (COP)
COD is yet another measure of oxygen demand. It measures the
amount of organic (and some inorganic) pollutants under a
carefully controlled, direct chemical oxidation by a dichromate-
sulfuric acid reagent. COD is a much more rapid measure of
oxygen demand than BODj>, and is potentially very useful.
However, it does not have the same significance, and at the
present time cannot be substituted for BOD5, because COD:BOD^
ratios vary with the types of wastes. The COD measures more than
only those materials that will readily biodegrade in a stream and
hence deplete the stream's dissolved oxygen supply. The COD
range for poultry processing plants is from 100 to 2,800 mg/1 in
the raw waste.
COD provides a rapid determination of the waste strength. Its
measurement will indicate a serious plant or treatment
malfunction long before the BODI5 can be run. A given plant or
waste treatment system usually has a relatively narrow range of
COD:BODj> ratios, if the waste characteristics are fairly
constant, so experience permits a judgment to be made concerning
plant operation from COD values. In the poultry processing
industry, COD ranges from about 1. 0 to 6 times the BOD5. in both
the raw and treatment wastes, with typical ratios between 1.5 and
3.0. Although the nature of the impact of COD on receiving
waters is the same as the BOD.5, BQDJ5 was chosen for inclusion in
the effluent limitations rather than COD because of the
industry's frequent use and familiarity with BOD5. COD
correlates with BOD5 and suspended solids (TSS) in both the raw
and final effluent, although the CODrTSS correlation is not as
good in the final as the raw.
Suspended Solids (TSS)
This parameter measures the suspended material that can be
removed from the waste waters by laboratory filtration, 'but does
not include coarse or floating matter that can be screened or
settled out readily. Suspended solids are a visual and easily
determined measure of pollution and also a measure of the
material that may settle in tranquil or slow-moving streams. A
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high level of suspended solids is an indication of high
Generally, suspended solids range from cne-third to three-fourths
of the BODj> values in the raw waste. Suspended solids are also a
measure of the effectiveness of solids removal systems such as
clarifiers and fine screens,
Suspended solids frequently become a limiting factor in waste
treatment when the BOD5 is less than about 20 mg/1. In fact, in
highly treated waste, suspended solids usually have a higher
value than the BODfS and in this case, it may Jbe easier to lower
the BOD5 even further^ perhaps to 5 to 10 mg/1, by filtering out
the suspended solids. TSS in the raw waste water from poultry
processing plants range from 75 to 1,100 mg/1. Suspended solids
in -the raw and treated waste waters of poultry processing plants
correlate well with BOD5, COD, and total volatile solids,
Suspended solids in receiving waters act as a substrate for
bacterial population. The substrate acts as adsorption surface
for ionic nutrients, thus resulting in high BOD5 values.
Suspended: solids also inhibit light penetration and thereby
reduce the primary productivity of algae (photosynthesis).
Because of the strong impact suspended solids can have on
receiving waters, suspended solids were included in the effluent
limitations reported in this report.
Suspended solids include both organic and inorganic materials.
The inorganic components include sand, silt, and clay. The
organic fraction includes such materials as grease, oil, tar,
animal and vegetable fats, various fibers, sawdust, hair, and
various materials from sewers. These solids may settle out
rapidly and bottom deposits are often a mixture of both organic
and inorganic solids. They adversely affect fisheries by
covering the bottom of the stream or lake with a blanket of
material that destroys the fish-food bottom fauna or the spawning
ground of fish. Deposits containing organic materials may
deplete bottom oxygen supplies and produce hydrogen sulfide,
carbon dioxide^ methane, and other noxious gases.
In raw watar sources for domestic use. State and regional
agencies generally specify that suspended solids in streams shall
not be present in sufficient concentration to be objectionable or
to interfere with normal treatment processes. Suspended solids
in water may interfere with many industrial processes, and cause
foaming in boilers, or encrustations on equipment exposed to
waterp especially as the temperature rises. Suspended solids are
undesirable in water for textile industries; paper and pulp;
beverages; dairy products; laundries; dyeing; photography;
cooling systems, and power plants. Suspended particles also
serve as a transport mechanism for pesticides and other
substances which are readily sorbed into or onto clay particles.
Solids may be suspended in water for a time, and then settle to
the bed of the stream or lake. These settleable solids
discharged with man's wastes may be inert? slowly biodegradable
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materials, or rapidly decomposable substances. While in
suspension, they increase the turbidity of the water, reduce
light penetration and impair the photosynthetic activity of
aquatic plants.
Solids in suspension are aesthetically displeasing. When they
settle to form sludge deposits on the stream or lake bed, they
are often much more damaging to the life in water, and tiiey
retain the capacity to displease the senses. Solids, when
transformed to sludge deposits, may do a variety of damaging
things, including blanketing the stream or lake bed and thereby
destroying the living spaces for those benthic organisms that
would otherwise occupy the habitat. When of an organic and
therefore decomposable nature, solids use a portion or all of the
dissolved oxygen available in the area. Organic materials also
serve as a seemingly inexhaustible food source for sludgeworms
and associated organisms.
Turbidity is principally a measure of the light-absorbing
properties of suspended solids. It is frequently used as a
substitute method of quickly estimating the total suspended
solids when the concentration is relatively low.
Total Dissolved Solids (TDS)
The total dissolved solids in the waste waters of most poultry
processing plants contain mainly inorganic salts. The amount of
dissolved solids will vary with the type of in-plant operations
and the housekeeping practices. Total dissolved solids range
from 170 to 2,300 mg/1 in the raw waste waters of poultry
processing plants. Dissolved solids are of the same order of
magnitude and correlate well with the total volatile solids in
the raw waste waters, implying that, in general, much of the
dissolved solids are volatile. The inorganic dissolved solids
are particularly important because they are relatively unaffected
by biological treatment processes. Therefore, unless removed,
they will accumulate within the water system on total recycle, or
reuse, or build up to high levels with partial recycle or reuse
of the waste water. Another salt sometimes present in
significant quantities is sulfate. This may come from sulfate in
the incoming raw water, or perhaps from water conditioning
treatment of the water supply. Sulfates become particularly
troublesome in causing odor in anaerobic treatment systems, where
they are converted to sulfides.
Dissolved solids affect the ionic nature of receiving waters and
are usually the nutrients for bacteria and protozoans. Thus,
they increase the eutrophication rate of the r jeiving bo£y of
water. Total dissolved solids were not included .n the effluent
limitations recommended in this report becai.se the organic
portion would be limited by BODj> limitations and the nutrient
portion by the nitrogen and phosphorus limitations.
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In natural waters the dissolved solids consist mainly of
carbonates, chlorides, sulfates, phosphates, and possibly
nitrates of calcium, magnesium, sodium, and potassium, with
traces of iron, manganese, and other substances.
Many communities in the United States and in other countries use
w-iter supplies containing 2,000 to 4,000 ing/1 of dissolved salts,
wii^n no better water is available. Such waters are not
palatable, may not quench thirst, and may have a laxative action
on new users. Waters containing more than 4,000 mg/1 of total
salts are generally considered linfit for human use, although in
hot climates such higher salt concentrations can be tolerated
whereas they could not be in temperate climates. Waters
containing 5,000 mg/1 or more are reported to be bitter and act
as bladder and intestinal irritants. It is generally agreed that
the salt concentration of good, palatable water should not exceed
500 mg/1.
Limiting concentrations of dissolved solids for freshwater fish
may range from 5,000 to 10,0^0 mg/1, according to species and
prior acclimatization. Some fish are adapted to living in more
saline waters, and a few species of freshwater forms have been
^ound in natural waters with a salt concentration of 15,000 to
20,000 mg/1. Fish can slowly become acclimatized to higher
salinities, but fish in waters of low salinity cannot survive
sudden exposure to high salinities, such as those resulting from
discharges of oil well brines. Dissolved solids may influence
the toxicity of heavy metals and organic compounds to fish and
other aquatic life, primarily because of the antagonistic effect
of hardness on metals.
Waters with total dissolved solids over 500 mg/1 have decreasing
utility as irrigation water. At 5,000 mg/1 water has little or
no value for irrigation.
Dissolved solids in industrial waters can cause foaming in
boilers and cause interference with the purity, color, or taste
of many finished products. High contents of dissolved solids
also tend to accelerate corrosion.:
Specific conductance is a measure bf the capacity of water to
convey an electric current. This property is related to the
total concentration of ionized substances in water and water
temperature. This property is frequently used as a substitute
method of quickly estimating the dissolved solids concentration.
Total Volatile Solids (TVS)
Total volatile solids is a rough measure of the amount of organic
matter in the waste water. Actually it is the amount of
combustible material in both the total dissolved solids and total
suspended solids. Total volatile solids in the raw waste waters
of poultry processing plants range from 175 to 2,400 mg/1. Total
volatile solids in the raw waste waters of poultry processing
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plants correlate well with BOD5, TSS, total dissolved solids and
COD; total volatile solids in the final waste waters correlate
well with BOD5 and TSS. Because of these correlations and
because total volatile solids is a relatively easy parameter to
determine, it could be used as a rapid method to determine a
serious plant or treatment system malfunction.
Volatile solids in receiving waters are food for microorganisms,
and thus increase eutrophication. Effluent limitations for total
volatile solids were not established because 1VS will be limited
by limitations on other pollutant parameters such as BOD5 and
suspended solids.
Grease
Grease, also called oil and grease, or hexane solubles, is a
major pollutant in the raw waste stream of poultry processing
plants. Grease forms unsightly films and layers on water,
interferes with aquatic life, clogs sewers, disturbs biological
processes in sewage treatment plants, and can also become a fire
hazard. Hence effluent limitations were established for grease.
The concentration of grease in poultry processing raw wastes
varies from 100 to 400 mg/1.
Grease may foul municipal treatment facilities, especially
trickling flitersp and seriously reduce their effectiveness.
Thus, it may be of great interest and concern to municipal
treatment plants.
Oil and grease exhibit an oxygen demand. Oil emulsions may
adhere to the gills of fish or coat and destroy algae or other
plankton. Deposition of oil in the bottom sediments can serve to
inhibit normal benthic growths, thus interrupting the aquatic
food chain. Soluble and emulsified material ingested by fish may
taint the flavor of the fish flesh. Water-soluble components may
exert toxic action on fish. Floating oil may reduce the re-
aeration of the water surface and in conjunction with emulsified
oil may interfere with photosynthesis. Water-insoluble
components damage the plumage and coats of water animals and
fowls. Oil and grease in a water can result in the formation of
objectionable surface slicks preventing the full aesthetic
enjoyment of the water.
Oil spills can damage the surface of boats and can destroy the
aesthetic characteristics of beaches and shorelines
Ammonia Nitrogen
Ammonia nitrogen is just one of many forms of nitrogen in a waste
stream. Anaerobic decomposition of protein, which contains
organic nitrogen, leads to the formation of ammonia. Thus,
anaerobic lagoons or digesters produce high levels of ammonia.
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Also, septic (anaerobic) conditions within the plant in traps,
basins, etc., may lead to ammonia in the waste water.
Ammonia is oxidized by bacteria into nitrites and nitrates by a
process called "nitrification." This may occur in an aerobic
treatment process and in a stream. Thus, ammonia will deplete
the oxygen supply in a stream; its oxidation products are
recognized nutrients for aquatic growth. Also, free ammonia in a
stream is known to be harmful to fish.
Typical concentrations in the raw waste range from 1 to 100 mg/1;
however, after treatment in an anaerobic system, the
concentrations of ammonia can reach 100 to 500 mg/1. Ammonia is
limited in drinking water to 0.05 to 0.1 mg/1.11 In some cases a
stream limitation is less than 2 mg/1. Effluent limitations for
1983 were established for ammonia because of the strong impact it
can have on receiving waters.
Ammonia is a common product of the decomposition of organic
matter. Doad and decaying animals and plants along with human
and animal body wastes account for much of the ammonia entering
the aquatic: ecosystem. Ammonia exists in its non-ionized form
only at higher pH levels and is the most toxic in this State.
The lower the pH, the more ionized ammonia is formed and its
toxicity decreases. Ammonia, in the presence of dissolved
oxygen, is converted to nitrate (NO3J by nitrifying bacteria.
Nitrite (NQ2) , which is an intermediate product between ammonia
and nitrate, sometimes occurs in quantity when depressed oxygen
conditions permit. Ammonia can exist in several other chemical
combinations including ammonium chloride and other salts.
In mc-st natural water the pH range is such that ammonium ions
(NH^t*) predominate. In alkaline waters, however, high
concentrations of un-ionized ammonia in undissociated ammonium
hydroxide increase the toxicity of ammonia solutions. In streams
polluted with sewage, up to one half of the nitrogen in the
sewage may i:e in the form of free ammonia, and sewage may carry
up to 35 mg/1 of total nitrogen. It has been shown that at a
level of 1.0 mg/1 un-ionized ammonia, the ability of hemoglobin
to combine with oxygen is impaired and fish may suffocate.
Evidence indicates that ammonia exerts a considerable toxic
effect on all aquatic life within a range of less than 1.0 mg/1
to 25 mg/1, depending on the pH and dissolved oxygen level
present.
Ammonia can add to the problem of eutrophication by supplying
nitrogen through its breakdown products. Some lakes in warmer
climates, and ethers that are aging quickly are sometimes limited
by the nitrogen available. Any increase will speed up the plant
growth and decay process.
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Kleldahl Nitrocten
This parameter measures the amount of ammonia and organic
nitrogen; when used in conjunction with the ammonia nitrogen, the
organic nitrogen can be determined by thf difference. Under
septic conditions, organic nitrogen decomposes to form ammonia.
Kjeldahl nitrogen is a good indicator of the crude protein in the
effluent and, hence, of the value of proteinaceous material being
lost in the waste water. The protein content is usually taken as
6.25 times the organic nitrogen. the sources of Kjeldahl
nitrogen are basically the same as f6r ammonia nitrogen, above.
The raw waste loading of Kjeldahl nitrogen is extremely variable
and is highly affected by blood loss to the waste waters such as
by drainage from byproduct trucks. Typical raw waste
concentrations of Kjeldahl nitrogen are between 50 and 100 mg/1.
Kjeldahl nitrogen has not been a common parameter for regulation
and is a much more useful parameter for raw waste than for final
ef f luent. Even so, ef fluent li mit a ti on s for 1983 were
established for Kjeldahl nitrogen because, in addition to ammonia
which has a strong environmental impact on receiving waters, it
can be a major source of organic material, which is food for
microorganisms in receiving waters.
Nitrates and Nitrites
Nitrates and nitrites, normally reported as N, are the result of
oxidatiort of ammonia and of organic nitrogen. Nitrates as N
should rjot exceed 20 mg/1 in water supplies.12 They are
essential nutrients for algae and other aquatic life. For these
reasons, effluent limitations for 1983 were established for
nitrites^nitrates as N. Nitrites typically range from 0.001 to
2.0 mg/1 in the raw wastes and from 0.02 to 1.0 mg/1 in the
treated wastes; nitrates range from O.I to 4.1 mg/1 in the raw
and from 0.15 to 17.5 mg/1 in the treated wastes.
Nitrates are considered to be among the poisonous ingredients of
mineralized waters, with potassium nitrate being more poisonous
than sodium nitrate. Excess nitrates cause irritation of the
mucous linings of the gastrointestinal tract and the bladder; the
symptoms are diarrhea and diuresis, and drinking one liter of
water containing 500 mg/1 of nitrate can cause such symptoms.
Infant methemoglobinemia, a disease characterized by certain
specific blood changes and cyanosis, may be caused by high
nitrate concentrations in the water, used for preparing feeding
formulae. While it is still impossible to s ate precise
concentration limits, it has been widely recommended that water
containing more than 10 mg/1 of nitrate nitrogen ,NO3-N) should
not be; used for infants. Nitrates are a so harmful in
fermentation processes and can cause disagreeable tastes in beer.
Nitrates and nitrites are important measurements, along with
Kjeldahl nitrogen, in that they allow for the calculation of a
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nitrogen balance on the treatment system. In fact, the field
sampling data verified that when there was a substantial nitrogen
reduction by the treatment system, it was accompanied by good
BOD5, TSS, and grease reduction.
Phosphorus
Phosphorus, commonly reported as P, is a nutrient for aquatic
plant life and can therefore cause an increased eutrophication
rate in water courses. The threshold concentration of phosphorus
in receiving bodies that can lead to eutrophication is about 0.01
mg/1. The primary sources of phosphorus in raw waste from
poultry processing plants are bone meal from cutting, detergents
used in cleanup, food additives, and boiler-water additives.
Effluent limitations were established for phosphorus for the 1983
limits because of its effect on eutrophication rates.
During the past 30 years, a formidable case has developed for the
belief that increasing standing crops of aquatic plant growths,
which often interfere with water uses and are nuisances to man,
frequently are caused by increasing supplies of phosphorus. Such
phenomena are associated with a condition of accelerated
eutrophication or aging of waters. It is generally recognized
that phosphorus is not the sole cause of eutrophication, but
there is evidence to substantiate that it is frequently the key
element in all of the elements required by freshwater plants and
is generally present in the least amount relative to need.
Therefore, an increase in phosphorus allows use of other, already
present, nutrients for plant growths. Phosphorus is usually
described, for this reasons, as a "limiting factor."
When a plant population is stimulated in production and attains a
nuisance status, a large number of associated liabilities are
immediately apparent. Dense populations of pond weeds make
swimming dangerous. Boating and water skiing and sometimes
fishing may be eliminated because of the mass of vegetation that
serves as a physical impediment to such activities. Plant
populations have been associated with stunted fish populations
and with poor fishing. Plant nuisances emit vile stenches,
impart tastes and odors to water supplies, reduce the efficiency
of industrial and municipal water treatment, impair aesthetic
beauty, reduce or restrict resort trade, lower waterfront
property values, cause skin rashes to man during water contact,
and serve as a desired substrate and breeding ground for flies.
Phosphorus in the elemental form is particularly toxic, and
subject to bioaccumulation in much the same way as mercury.
Colloidal elemental phosphorus will poison marine fish (causing
skin tissue breakdown and discoloration). Also, phosphorus is
capable of being concentrated and will accumulate in organs and
soft tissues. Experiments have shown that marine fish will
concentrate phosphorus from water containing as little as 1 ug/1.
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Chloride
Chlorides in concentrations of the order of 5,000 mg/1 can be
harmful to people and other animal life,. High chloride
concentrations in waters can be troublesome for certain
industrial uses and for reuse or recycling of water. The
concentrations in raw waste are extremely variable from plant to
plant. Chloride loadings are unaffected by biological treatment
systems used by the industry today, and once in the waste waters
they are very costly to remove. While high chloride
concentrations in biological treatment systems and receiving
waters can upset the metabolic rate of organisms, effluent
concentrations are probably too low to have a serious impact.
Consequently chloride effluent limitations were not established
in this report.
Fecal Coliform
The coliform bacterial contamination (total and fecal) of raw
waste is substantially reduced in, the larger waste treatment
systems used in the industry, such as anaerobic lagoons followed
by several aerobic lagoons. Chlorination will reduce coliform
counts to less than 400 per 100 ml for total, and to less than
100 per 100 ml for fecal. Typically, States require that the
total coliform count not exceed 50 to 200 MPN {most probable
number) per 100 ml for waste waters discharged into receiving
waters. Hence, most final effluents require chlorination to meet
State limitations. When waters contain greater than 200 counts
of fecal coliform per 100 ml, it is assumed that pathogenic
enterobacteriacea, which can cause intestinal infections, are
present. Consequently, effluent limitations were established for
fecal coliform.
Fecal coliforms are used as ah indicator since they have
originated from the intestinal tract of warmblooded animals.
Their presence in water indicates the potential presence of
pathogenic bacteria and viruses.
The presence of coliforms, more specifically fecal coliforms, in
water is indicative of fecal pollution. In general, the presence
of tecal coliform organisms indicates recent and possibly
dangerous fecal contamination. When the fecal coliform count
exceeds 2,000 per 100 ml there is a high correlation with
increased numbers of both pathogenic viruses and ba< teria.
Many microorganisms, pathogenic to humans and .nimals, may be
carried in surface water, particularly that deriv d from effluent
sources which find their way into surface water from municipal
and industrial wastes. The diseases associated with bacteria
include bacillary and amoebic dysentery. Salmonella
gastroenteritis, typhoid and paratyphoid fevers, leptospirosis.
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chlorea,, vibriosis and infectious hepatitis. Recent studies have
emphasized the value of fecal coliform density in assessing the
occurrence of Salmonella, a common bacterial pathogen in surface
water. Field studies involving irrigation water, field crops,
and soils indicate that when the fecal coliform density in stream
waters exceeded 1,000 per 100 ml, the occurrence of Salmonella
was 53-5 percent.
pHff Acidity* and Alkalinity
pH is of relatively minor importance, although waters with pH
outside the 6.0 to 9.0 range can affect the survival of most
organi^mSj, particularly invertebrates. The usual pH for raw
waste falls between 6,0 to 9.0. This pH range is close enough to
neutrality that it does not significantly affect treatment
effectiveness or effluent quality. However, some adjustment may
be required, particularly if pH adjustment has been used to lower
the pH for protein precipitation, or if the pH has been raised
for ammonia stripping. The pH of the waste water then should be
returned to its normal range before discharge. The effect of
chemical additions for pH adjustment should be taken into
consideration^ as new pollutants could result.
Acidity and alkalinity are reciprocal terms. Acidity is produced
by substances that yield hydrogen icns upon hydrolysis and
alkalinity is produced by substances that yield hydroxyl ions.
The terirs "total acidity" and "total alkalinity" are often used
to express the buffering capacity of a solution. Acidity in
natural waters is caused by carbon dioxide, mineral acids, weakly
dissociated acids, and the salts of strong acids and weak bases.
Alkalinity is caused by strong bases and the salts of strong
alkalies and weak acids,
The term pK is a logarithmic expression of the concentration of
hydrogen ions. At a pH of 7, the hydrogen and hydroxyl ion
concentrations are essentially equal and the water is neutral.
Lower pH values indicate acidity while higher values indicate
alkalinity,, The relationship between pH and acidity or
alkalinity is not necessarily linear or direct.
Waters with a pH below 6.0 are corrosive to waterworks
structures, distribution lines, and household plumbing fixtures
and can thi;s add such constituents to drinking water as iron,
copper, zinc, cadmium and lead. The hydrogen ion concentration
can affect the taste of the water. At a low pH, water tastes
"sour," The bactericidal effect of chlorine is weakened as the pH
increases, and it is advantageous to keep the pH close to 7.
This is very significant for providing safe drinking water.
Extremes of pH or rapid pH changes can exert stress conditions or
kill aquatic life outright. Dead rish, associated algal blooms,
and foul stenches are aesthetic liabilities of any waterway.
Even moderate changes from "acceptable" criteria limits of pH are
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deleterious to some species. The relative toxicity to aquatic
life of many materials is increased by changes in the water pH.
Metalocyanide complexes can increase a thousand-fold in toxicity
with a drop of 1.5 pH units. The availability of many nutrient
substances varies with the alkalinity and acidity. Ammonia is
more lethal with a higher pH.
The lacrimal fluid of the human eye has a pH of approximately
7.0, and a deviation of 0.1 pH unit from the norm may result in
eye irritation for the swimmer- Appreciable irritation will
cause severe pain.
Because of the long detention time at ambient temperatures
associated with typically large biological treatment systems used
for treating poultry processing waste water, the temperature of
the treatment effluent from most poultry processing plants will
be virtually the same as the temperature of the receiving body of
water. Therefore, temperature effluent limitations were not
established. Temperatures of the raw waste waters are typically
about 18°C (65°F).
Temperature is one of the most important and influential water
quality characteristics. Temperature determines those species
that may be present; it activates the hatching of young,
regulates their activity, and stimulates or suppresses their
growth and development; it attracts, and may kill wher the water
becomes too hot or becomes chilled too suddenly. Colder water
generally suppresses development. Warmer water generally
accelerates activity and may be a primary cause of aquatic plant
nuisances when other environmental factors are suitable.
Temperature is a prime regulator of natural processes within the
water environment. It governs physiological functions in
organisms and, acting directly or indirectly in combination with
other water quality constituents, it affects aquatic life with
each change. These effects include chemical reaction rates,
enzymatic functions, molecular movements, and molecular exchanges
between membranes within and between the physiological systems
and the organs of an animal.
Chemical reaction rates vary with temperature and generally
increase as the temperature is increased. The solubility of
gases in water varies with temperature. Dissolved oxygen is
decreased by the decay or decomposition of dissolved organic
substances and the decay rate increases as the temperature of the
water increases, reaching a maximum at about 3' C (86QF). The
temperature of stream water, even during summer, is below the
optimum for pollution-associated bacteria. Increasing the water
temperature increases the bacterial multiplication rate when the
environment is favorable and the food supply is abundant.
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Reproduction cycles may be changed significantly by increased
temperature because this function takes place under restricted
temperature ranges- Spawning may not occur at all because
temperatures are too high. Thus, a fish population may exist in
a heated area only by continued immigration. Disregarding the
decreased reproductive potential, water temperatures need not
reach lethal levels to decimate a species. Temperatures that
favor competitors, predators, parasites, and disease can destroy
a species at levels far below those that are lethal.
Fish food organisms are altered severely when temperatures
approach or exceed 90°F. Predominant algal species change,
primary production is decreased, and bcttom-associated organisms
may be depleted or aItered drasti cally in numbers and
distribution. Increased water temperatures may cause aquatic
plant nuisances when other environmental factors are favorable.
Synergistic actions of pollutants are more severe at higher water
temperatures. Given amounts of domestic sewage, refinery wastes,
oils, tars, insecticides, detergents, and fertilizers more
rapidly deplete oxygen in water at higher temperatures, and the
respective toxicities are likewise increased.
When water temperatures increase, the predominant algal species
may change from diatoms to green algae, and finally at high
temperatures to blue-green algae, because of species temperature
preferentials. Blue-green algae can cause serious odor problems.
The number and distribution of benthic organisms decreases as
water temperatures increase above 90°F, which is close to the
tolerance limit for the population. This could seriously affect
certain fish that depend on benthic organisms as a food source.
The cost of fish being attracted to heated Water in winter months
may be considerable, due to fish mortalities that may result when
the fish return to the cooler water.
Rising temperatures stimulate the decomposition of sludge,
formation o£ sludge gas, multiplication of saprophytic bacteria
and fungi (particularly in the presence of organic wastes), and
the consumption of oxygen by putrefactive processes, thus
affecting the esthetic value of a water course.
In general, marine water temperatures do not change as rapidly or
range as widely as those of freshwater. Marine and estuarine
fishes, therefore* are less tolerant of temperature variation.
Although this limited tolerance is greater in estuarine than in
open-water marine species? temperature changes are more important
to those fishes in estuaries and bays than to those in open
marine areas, because of the nursery and replenishment functions
of the estuary that can be adversely affected by extreme
temperature changes.
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SECTION VII
CONTROL AND TREATMENT TECHNOLOGY
SUMMARY
The waste load discharged from the poultry processing industry to
receiving streams can be reduced to desired levels, including no
discharge of pollutants, by conscientious water management, in-
plant waste controls, process revisions, and by the use of a
primary, biological and advanced was^te water treatment. Figure 9
is a schematic of a suggested waste reduction program for the
poultry industry to achieve a high quality effluent.
This section describes many of the techniques and technologies
that are available or that are being developed to achieve the
various levels of waste reduction. In-plant control techniques
and waste water management suggestions are described first.
Waste treatment technology normally used as a primary treatment
is then described. In the case of the poultry processing
industry, this "primary" treatment is considered as part of the
in-plant system, although many of these systems have been
installed to reduce pollution levels as well as to recover
byproducts. The effluent from primary treatment is considered
the "raw waste." Secondary treatment systems are used in the
treatment of the raw waste.
Each treatment process is described, and the specific advantages
and disadvantages of each system, and the effectiveness of the
specific waste water contaminants foxind in poultry processing
waste are discussed. The advanced treatment systems that are
applicable to the waste from typical poultry plants are described
in the last part of this section. Some of these advanced
treatment systems have not been used on full-scale for poultry
processing plant waste; therefore, the development status,
reliability, and potential problems are discussed in greater
detail than for the primary and biological treatment systems that
are in widespread use.
IN-PLANT CONTROL TECHNIQUES
The waste load from a poultry processing plant is composed of a
waste water stream containing the; various pollutants described in
Section VI. The cost and effectiveness of treatment of the waste
stream will vary with the quantity of water and the waste load.
In-plant control techniques will reduce both water use and waste
load. The latter will be reduced by minimizing the entry of raw
materials into the waste water stream, and the former by cleanup
frequency and procedures and by controlling the water use for
high water-use operations and by reusing waste w .ters.
The in-plant changes that may be made in each plant to reduce
water use and waste load will depend upon the particular
-------
Waste Reduction
Techniques
CO
Waste Reduction
Effect
Point of
Application
Waste
Water
Mgmt. &
In-Plant
Controls
Water-
Flow &
Waste
Load
Reduction
Plant
Operations
— *
Screening,
Skimming,
Settling -
3y- Product
Recovery
and Primary
Treatment
By- Produce
Recovery,
Grease,
& Coarse
Solids
Removal
In-Plant
—+
**
Dissolved
Air
Flotation
By-Product
Recovery,
Grease,
Sus. Solid:
Removal
In-Plant
Secondary
BOD, Sus.
Solids,
Grease
Removal
to 97.7%
BOD 5
End-of
Process
-*
Partial
Tertiary
Treatment
]
j Irrlg
j Evapoi
i
.
it ion
-ation
Removal of
Fine Sus.
Solids, Salt,
Phosphorus ,
Ammonia (as
necessary)
to 97.7%
SOD5
Post
Secondary
Treatment
No
Discharge
Post
Secondary
Treatment
"Figure '9. Suggested -Poultry..Processing Industry Waste Reduction Program
-------
circumstances at that plant. A good understanding of the sources
of water use and waste load, however, would be very useful prior
to implementation of improved jvater management practices. Waste
water and waste load sources are discussed in detail in Section
V. Unfortunately, efforts made by many poultry processing plants
to improve the quality of the final treated effluent have been
directed at improvements in the treatment system only, and not in
in-plant control techniques.
The following is a list of in-plant control techniques which have
been used by poultry processing plants or have been shown to be
technically feasible in other applications for improving water
management practices:
o Appoint a person with specific responsibility for waste and
water management. This person should have reasonable powers
to enforce improvements, both in the plant and outside.
o Determine or estimate water use and waste load strength
from various sources. Install flowmeters and monitor flows
in all major water use areas.
o Control and minimize flow of freshwater at major outlets
by installing properly sized spray nozzles and by regulating
pressure on supply lines. On hand washers, this may require
installation of press-to-operate valves.
o Stun birds in the killing operation to reduce carcass
movement during bleeding,
o Confine bleeding and provide for sufficient bleed time.
Recover all collectable blood and ship to rendering in tanks
rather than by dumping on top of offal.
o Use minimum OSDA-approved quantities of water in the scalder
and chillers.
o Shut off all unnecessary water flow during work breaks.
o Consider the reuse of chiller water for makeup water for the
scalder. This may require preheating the chiller effluent
with the scalder overflow water by using a simple heat
exchanger.
o consider dry offal handling as an alternative to fluming.
A number of plants had demonstrated the feasibility of dry
offal handling in modern high-production poultry slaughtering
operations.
o Control the water use in gizzard machine.
o Provide for regularly scheduled observanca of screening
and handling systems, for offal and feathers. A back-up
screen may be required to prevent these materials from
entering municipal or private waste treatment systems where
85
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they may cause problems.
o Treat ofifal truck drainage before sewering. One method is
to steam sparge the collected drainage and then screen.
o Use dry cleanup prior to washdown on all floors and tables
to reduce the waste load- This is particularly important
in the bleeding and cutting areas and all other areas hThere
there tends to be spillage of materials*
o Use high-pressure, low-volume spray nozzles or
steam-augmented systems for plant
o Minimize the amount of chemicals and detergents to prevent
emulsification or solubilizing of solids in the waste watery,
For example,, determine the minimum amount of chGRlcals that
will be effective in cleaning the scald tank.
o Control inventories of raw materials used in further
processing so that none of these materials are ever wjs-tacl
to the sewer. Spent raw materials ?houl-3 be routed to
rendering.
o Treat separately all overflow of cooking broth for grease
and solids recovery.
o Make all employees aware of good water management practices
and encourage them to apply these practices.
Byproduct Recovery (Screening)
Byproduct recovery of offal and feathers from flow-away systems
in the slaughtering and dressing of poultry is accomplished by
various screening techniques. These operations may or may not be
followed by in-plant primary treatment such as gravity separation
basins or air flotation systems, or even biological screening
systems,
Screens vary widely both in mechanical action and in mesh size,
which ranges from 0. 5-inch openings in stationary screens to 200
mesh in high-speed circular vibratory polishing screens. In some
cases the efficiency of screening in the flow-away systems may be
sufficient to circumvent biological screening; in others,
biological or polishing screening may be warranted. Floor drains
not connected to the flow-away systems are usually then
discharged to this polishing screen. With no biological
screening, the floor drains in the offal room and those adjacent
to the flow-away screens and offal conveyors should be pumped
back to the flow-away screen influent. These floor drains a*e
frequently the source of serious problems when diff icult.ies arise
in the flow-away screen systems or conveyors.
86
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Rotary Screens
Rotary and vibratory screens are the most popular types of
screening systems used by the poultry industry for offal and
feather recovery from the flow-away systems. One type of barrel
or rotary screen, driven by external rollers, receives the waste
water at one open end and discharges the solids at the other open
end. The screen is inclined toward the exit end to facilitate
movement of solids. The liquid passes outward through the screen
(usually stainless steel screen cloth or perforated sheet) £o a
receiver and then to the sewer. To prevent clogging, the screen
is usually sprayed continuously by a line of external spray
nozzles.l3 •
Another rotary screen occasionally used for byproduct recovery or
for in-plant primary in the poultry industry^ is driven by an
external pinion gear* The raw waste water is fed into the
interior of the screen, below the longitudinal axisp and solids
are removed in a trough-and-screw conveyor mounted lengthwis^ at
the axis (center line) of the barrel. The liquid exits outward
through the screen into a tank under the screen. The screeri is
partially submerged in the liquid in the tank. The screen is
usually UO by UO mesh, with G0<4 mm (1/6** inch) openings.
Perforated lift paddles mounted lengthwise on the inside surface
of the screen assist in lifting the solids to the conveyor
trough. This type is also generally sprayed externally to reduce
blinding. Grease clogging can be reduced by coating the wire
cloth with tefIon. Solids remova1 up to 82 percent is
reported*t3
Applications
A broad range of applications exists for screens for both
byproduct recovery and for in-plant primary waste water
treatment. These include both the plant waste water and waste
water discharged from individual sources, especially streams with
high solids contents sxich as offal truck drainage. In one modern
poultry treatment facility, a rotary screen equipped with
microscreening was successfully used for advanced treatment—the
final BOD5 from this plant was consistently under 15 mg/1.
Vibrating Screens
Vibratory screens are commonly used to recover offal and
feathers. The effectiveness of a vibrating screen depends on a
rapid motion. Vibrating screens operate between 99 and 1,800
rpm; the motion can be either circular or straight .ine, varying
from 0.08 to 1.27 cm (1/32 to 1/2 inch) total tra el. The speed
and motion are selected by the screen manufacturer for the
particular application.
Of prime importance in the selection of a proper vibrating screen
is the application of the proper cloth. The liquid capacities of
87
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vibrating screens are based on the percent of open area of the
cloth. The cloth is selected with the proper combination of
strength of wire and percent of open area. If the waste solids
to be handled are heavy and abrasive, wire of greater thickness
should be used to assure long life,, However, if the material is
light or sticky in nature, the durability of the screening
surface may be the least consideration. In such a case, a light
wire may be desired to provide an increased percent of open area.
Applications
For offal recovery, vibratory screens usually have 20-mesh
screening; for feather removal as well as for in-plant primary
treatment of combined waste water, a 36- by UO-mesh screen cloth
is used. On most applications a double-crimped, square-weave
cloth is used because of its inherent strength and resistance to
wire shifting. Vibratory screens with straight-line action are
largely used for byproduct recovery, while those with circular
motion are frequently used for in-plant primary treatment.
Static Screens
The primary function of a static screen is to remove "free" or
transporting fluids. This can be accomplished in several ways,
and in most older conceptse only gravity drainage is involved. A
concavely curved screen design using high-velocity pressure
feeding was developed and patented in the 1950's for mineral
classification and has been adapted to other uses in the process
industries., This design employs bar interference to the slurry
which knives off thin layers of the flow over the curved
surface.**
Beginning in 1969, United States and foreign patents were allowed
on a three-slope static screen made of specially coined curved
wires. This concept used the Coanda or wall attachment
phenomenon to withdraw the fluid from the underlayer of a slurry
which is stratified by controlled velocity over the screen. This
method of operation has been found to be highly effective in
handling slurries containing fatty or sticky fibrous suspended
matter.
The specific arrangement and design of transverse wires provides
a relatively nonclogging surface for dewatering or screening.
The screens are precision-made, usually of 316 stainless steel,
and are extremely rugged. Harder, wear-resisting stainless
alloys may also be used for special purposes. Openings of 0.025
to 0,15 cm (0,010 to 0-060 inch) meet normal screening needs.
Application
In some plants "follow-up" stationary screens, consisting of two,
three9 and four units placed vertically in the effluent sewer
before discharge to the municipal sewer, have successfully
88
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prevented escape of feathers and solids from the drains in the
flow*-away screen room and other drains on the premises. These
stationary "channel" screens are framed and are usually
constructed of mesh or perforated stainless steel with 1/4- to
1/2-inch openings. The series arrangement permits removal of a
single screen for cleaning and improves efficiency. -The three-
slope static screen is being used in a few poultry processing
plants as primary treatment.
IN-PLANT^PRIMARY TREATMENT
Ihr plant primary treatment in the poultry processing industry is
the treatment of waste water after the customary screening out of
byproducts from flow- away systems and before discharge to a
municipal sewer or private treatment system.
Flow Equalization
Equalization facilities consist of a holding tank and pumping
equipment designed to reduce the fluctuations of waste water flow
jthroutfh materials recovery systems. They can be economically
advantageous, whether the industry is treating its own wastes or
discharging into a city sewer after some pretreatment. The
equalising tank should have sufficient capacity to provide for
uniform flow to treatment facilities throughout a 24-hour day.
The tank is characterized by a varying flow into the tank and a
constant flow out.
The major advantages of equalization are that treatment systems
can be smaller since they can be designed for the 24-hour average
rather than the peak flows, and many waste treatment systems
operate much better when not subjected to shock loads or
variations in feed rate. Flow equalization is vital for proper
operation of air flotation systems'* particularly when chemicals
have been added.
Screens
Since so much of the pollutant matter for some waste sources of
poultry processing is originally solid (meat and fat particles) ,
interception of the waste material by various types of screens is
a natural f^rst step for primary treatment. To assure the best
performance on a plant waste wate*r stream, flow equalization may
be headed preceding screening equipment.
Unfortunately, when the pollutant materials er.ter the sewage
stream, they are subjected to turbulence, pumping, and mechanical
screening, and they break down and release solubl . BOD5 into the
stream, along with colloidal, suspended, an grease solids.
Wa^te treatment — that is, the removal of soluble , colloidal, and
suspended organic matter — is expensive. It usually is far
simpler and less expensive to keep the solids out of the sewer.
89
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Static, vibrating, and rotary screens are the primary type used
for this step in the in-plant primary treatment. These types of
screening systems were previously discussed in this section under
byproduct recovery. The main difference between the screening
systems used for byproduct recovery and those used for primary
treatment, is that the openings in the screening cloth for
primary treatment are normally smaller—36 to 200 mesh for
primary versus 20 mesh to 1.25 cm openings for byproduct
recovery, whenever possible, pilot-scale studies are warranted
before selecting a screen, unless specific operating data are
available for the specific use intended, in the same solids
concentration range, and under the same operating conditions.
Catch Basins
The catch basin for the separation of grease and solids from
poultry processing waste waters are being installed primarily for
waste control rather tjian to recover marketable grease.
Unfortunately many catch basins in use today are not equipped
with automatic bottom sludge removal equipment. The solids in
these basins could often be completely drained to the sewer or
are "sludged out" periodically at frequencies such that septic
conditions would not cause the sludge to rise. Rising sludge was
undesirable because it couloj affect the color and reduce the
market value of the grease. < Many wet wells or sumps that receive
the screened flow-away waters are considered catch basins by the
industry. However the turbulence created as the screened waters
fall by gravity into these pits does not permit efficient
separation of solids or grease. Furthermore, these basins are
not equipped with automatic skimming devices and hence grease
must be removed manually, wjiich is normally done once a day.
In the past twenty years, with waste treatment gradually becoming
an added economic incentive, catch basin design has been improved
in the solids removal area as well. In fact, the low market
value of inedible grease and tallow has reduced concern about
quality of the skimmings, and now the concern is shifting toward
overall effluent quality improvement. Gravity grease recovery
systems will remove 20 to 30 percent of the BOD5., 40 to 50
percent of the suspended solids, and 50 to 60 percent of the
grease (hexane solubles).1?
The majority of the newer gravity grease recovery basins (catch
basins) are rectangular. Flow rate is the most important
criterion for design; 30 to 40 minutes detention time at one-hour
peak flow is a common design sizing factor.13 The use of an
equalizing tank ahead of the catch basin obviously minimizes the
size requirement for the basin. A shallow basin-up to 1.8 m (6
feet)—is preferred.
A "skimmer" skims the grease and scum off the top into collecting
troughs. A scraper moves the sludge at the bottom into a
submerged hopper from which it can be pumped or carries it up and
90
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deposits it into a hopper. Both skimmings and sludge can be
recycled as a raw material for rendering.
Two identical catch basins, with a common wall, are desirable so
operation can continue if pne is down for maintenance or repair.
Both concrete and steel tanks are used.
Concrete tanks have the inherent advantages of lower overall
maintenance and more permanence of structure. However, some
plants prefer to be able to modify their operation for future
expansion or alterations, or even relocation. All-steel tanks
have the advantage of being semiportable, more easily field-
erected, and more easily modified than concrete tanks. The all-
steel tanks, however, require additional maintenance as a result
of wear from abrasion and corrosion.
A tank using all-steel walls and a concrete bottom is probably
the best compromise between the all-steel tank and the all-
concrete tank. The advantages are the same as for steel;
however, the all-steel tank requires a footing underneath and
supporting members, whereas the concrete bottom forms the floor
and supporting footings for the steel-wall tank.
Dissolved Air Flotation
This system is, by definition, a primary treatment system; thus,
the effluent from a dissolved air flotation system is considered
raw waste. This system is normally used to remove grease and
fine suspended solids. It is a relatively recent technology in
the poultry processing industry; therefore, it is not in
widespread use, although increasing numbers of plants are
installing these systems.
Dissolved air flotation appears to be the single, most effective
device currently in commerpial use for a plant to use to reduce
the pollutant waste loa£ in its raw waste water stream, and is
particularly effective when flow equalization tanks precede the
flotation unit. It is expected that the use of dissolved air
flotation will become more common in the industry, especially as
a step in achieving the 1983 limitations.
Technical Description
Air flotation systems are used to remove any suspended material
from waste water with a specific gravity close to that pf water.
The dissolved air system generates a supersaturated solution of
waste water and air by pressurizing waste water and introducing
compressed air, then mixing the two in a detention tank. This
"supersaturated" waste water flows to a large flotation tank
where the pressure is released, thereby generating numerous small
air bubbles which effect the flotation of the suspended organic
material by one of three mechanisms: 1) adhesion of the air
bubbles to the particles of matter; 2) trapping of the air
91
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bubbles in the floe structures cf suspended material as the
bubbles rise; and 3) adsorption of the air bubbles as the floe
structure is formed from the suspended organic matter,15 In most
cases, bottom sludge removal facilities are also provide^.
There are three process alternatives that differ by the
proportion of the waste water stream that is pressurized and into
which the compressed air is mixed. In the total pressurization
process. Figure 10, the entire waste water stream is raised to
full pressure for compressed air injection.
In partial pressurization. Figure 11, only a part of the waste
water stream is raised to the pressure of the compressed air for
subsequent mixing. Alternative A of Figure 11 shows a sidestream
of influent entering th§ detention tank, thus reducing the
pumping required in the system shown in Figure 10. In the
recycle pressurization process, alternative B of Figure 11,
treated effluent from the flotation tank is recycled and
pressurized for mixing with the compressed air and then, at the
point of pressure release, is mixed with the influent waste
water. Operating costs may vary slightly, but performance should
be essentially equal among the alternatives. Improved
performance of the air flotation system is achieved by
coagulation of the suspended matter prior to treatment. This is
done by pH adjustment or tf|e addition of coagulant chemicals, or
both. Aluminum sulfate, iron sulfate, lime, and polyelectrolytes
are used as coagulants at varying concentrations up to 300 to 400
mg/1 in the raw waste. These chemicals are essentially totally
removed in the dissolved air unit, thereby adding littl^ or no
load to the downstream waste treatment systems. However, the
resulting float and sludge may become a less desirable raw
material for recycling through the rendering process as a result
of chemical coagulation addition. Chemical precipitation is also
discussed later, particularly in regard to phosphorus removal,
under advanced treatment; phosphorus can also be removed at this
primary (in-plant) treatment stage. A slow paddle mix will
improve coagulation. It has been suggested that the
proteinaceous matter in poultry processing plant waste could be
removed by reducing the pt^ of the waste water to the isoelectric
point of about 3.5.1S The proteinaceous material would be
coagulated at that point; and readily removed as float from the
top of the dissolved air unit. This is not being done
commercially in the poultry industry in the United States at the
present time.
Similarly, the Alwatec process has been developed using a
lignosulfonic acid precipitation and dissolved air flotation to
recover a high protein product that is valuable as a feed.1*
Nearly instantaneous protein precipitation and hence, nitrogen
removal, is achieved when a high protein-containing effluent is
acidified to a pH between 3 and U with a high molecular weight
lignosulfonic acid. BOD5 reduction is reported to range from 60
to 95 percent. The effluent must be neutralized before further
treatment by the addition of milk of lime or some other
inexpensive alkali. This process is being evaluate^ on meat
92
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Feed
Compressed
Air
Toto I Pressurization
Process
Treated
Effluent
Float
Sludge
Figure 10. Dissolved Air Flotation
-------
Compressed
Air
Recycle Pressunzcmon
Process
(Alternative 8)
, (Retention W
r \ Tank
Treated
Feed from ^
Primary i — /^ >
Treatment ! i
Flotation
Tank
1 ^
V
iri^
1 jj Retention ] 1
Tank
Sludge
Compressed
Air
Partial Pressurization
Process
(Alternative A)
Figure 11. Process Alternatives for Dissolved Air Flotation
-------
packing waste in one plant in the United States at the present
time.l7
Orie of the manufacturers of dissolved air flotation equipment
indicated a 60 percent suspended solids removal and 80-to-90
percent grease removal without the addition of chemicals. With
the addition of 300 to 400 mg/1 of inorganic coagulants and a
slow mix to coagulate the organic matter, the manufacturer says
that 90 percent or more of the suspended solids and more than 90
percent of the grease can be removed.ie Total nitrogen reduction
between 35 and 70 percent was found in dissolved air units
surveyed in the meat packing industry.l9
North star's staff observed the operation of several dissolved
air units during the verification sampling program and plant
visits of the poultry, rendering, and meat packing industries.
One meat packing plant that was visited controlled the feed rate
and pH of the waste water and achieved 90-to-95 percent removal
of solids and grease; one poultry processing plant consistently
obtained about 80-percent BOD5 reduction with the aid of chemical
coagulants. Other plants had relatively good operating success,
but some did not achieve the results that should have been
attainable. It appeared that they did not fully understand the
process chemistry and were using poor operating procedures.
Problems and Reliability
The reliability of the dissolved air flotation process and of the
equipment seems to be well established, although it is relatively
new technology for the poultry industry. As indicated above, it
appears that the use of the dissolved air system is not fully
exploited by some of the companies who have installed it for
waste water treatment. The potential reliability of the
dissolved air process can be realized by proper installation and
operation. The feed rate and process conditions must be
maintained at the proper levels at all times to assure this
reliability. This fact does not seem to be fully understood or
of sufficient concern to some companies and thus full benefit is
frequently not achieved.
The sludge and float taken from the dissolved air system can both
be disposed of with the sludges obtained from biological waste
treatment systems. The addition of polyelectrolyte chemicals was
reported to create some problems for sludge dewatering. The
mechanical equipment involved in the dissolved air flotation
system is fairly simple, requiring limited maintenance attention
for such things as pumps and mechanical drives.
Electrocoaqulation
The concept of electrocoagulation is not new, but only recently
has such a system been developed and used to pretreat the raw
effluent from the meat products industries. Results reported on
treating slaughterhouse effluents*° show a marked reduction in
95
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waste strength when the effects of chemicals plus electric
current were added to a catch basin. The waste strength of the
effluent from the catch basin alone was 1,213, 465, and 1,108
mg/1 for suspended solids, grease, and BOD5., respectively; the
respective values for a catch basin plus chemicals plus electric
current were 65, 15, and 458 mg/1. Even a greater reduction
resulted when pH adjustment was also used. The increased
reduction, however, adds to equipment, chemical, and power cost.
In the case cited above, the equipment costs were increased by
$23,000 to $30,000 and the chemicals and power costs were about
$109/day and $5,76/day, respectively.
Technical Discussion
Electrocoagulation provides relatively rapid flotation and
compaction of the floe and can be used alone or in conjunction
with flocculants. As its name implies, the process
electrolytically neutralizes the charge on the foreign particles
to aid in forming the floe. The tank acts as the cathode, and a
plurality of anodes is placed in the waste water. A direct
current, with voltage less than 15 v, is passed through the waste
water. Cations formed at the cathode act to neutralize the
negative charge on the foreign particles, allowing them to
coagulate and form an embryo floe. Microbubbles of oxygen and
hydrogen formed during the electrolysis become entrained and
occluded in the embryo floe, causing it to rise to the surface.
The skimmings have a high solids content (9 to 12 percent,
compared to 3 to 5 percent by air flotation). Where the fat
loading is high, the solids content can be as high as 50 percent-
-the fat has a lower density than water, and it is hydrophobic.
Oxidation of constituents that can be oxidized at the operating
voltage occurs at the anodes; e.g., if sulfide is present in the
wastewater, sulfur will be formed. If chloride is present,
chlorine is formed and is effective as a disinfectant, reducing
bacteria counts.
There are also indications that the microbubbles themselves carry
a positive charge, which helps to neutralize the negative charge
on the foreign particles.
The choice of electrode material is important if the process is
to be efficient and trouble free. It is important not to use an
anode that has an appreciable dissolution rate, and especially
important not. to use an anode that puts toxic ions into the
solution.
The placement of the electrodes is also critical. The electrodes
are placed to get the desired field gradient; a higher gradient
at the inlet to the tank provides a higher incidence of particle
collisions required for coagulation.
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WASTE WATER TREATMENT SYSTEMS
The biological treatment methods commonly used for the treatment
of poultry processing plant wastes after in-plant primary
treatment (solids removal) are the following biological systems:
anaerobic processes, aerobic lagoons, and variations of the
activated sludge process. Several of these systems are capable
of providing up to 97-percent BOD5 reductions and 95-percent
suspended solids reduction, as observed at facilities in all
segments of the meat industry. Combinations of these systems can
achieve reductions up to 97.7 percent in BOD5, up to 96.7 percent
in grease, and up to 97.7 percent in suspended solids for poultry
processing plant waste water. Based on preliminary operating
data, the rotating biological contactor also shows potential as a
biological treatment system.
The selection of a biological system for treatment of poultry
processing plant wastes depends upon a number of important system
characteristics. Some of these are waste water volume, waste
load concentration, equipment used, pollution reduction
effectiveness required, reliability, consistency, and resulting
biological pollution problems (e.g., sludge disposal and odor
control). The principals governing the design and operation of
lagoon systems are the same for any substantially organic waste,
i.e.,municipal (domestic) wastes, meat processing wastes, or
vegetable processing wastes. Each source, however, possesses
somewhat differing characteristics in waste strength which
necessitate design adjustments, but all such wastes are highly
amenable to biological treatment. Poultry processing wastes are
readily degraded by biological processes, thus lagoon systems and
other biological treatment are particularly appropriate.
Geographical location of the poultry plant has a distinct bearing
on the design and operation of such treatment; in turn, design
and operation can readily accommodate temperature considerations
in any given area.83 Northern locations may dictate longer
hydraulic or solids detention times than in southern areas,
whereas southern locations may require more frequent cleanup (by
draining lagoons) or lower organic loading rates than in northern
areas. Expected reduction in effluent flow relative to raw waste
flow (as may be due to evaporation or seepage from lagoons) is
also important in design. Some plants have already incorporated
a "polishing" clarifier as part of biological treatment. This
helps by both removing suspended solids and permitting recycle of
sludge for balancing organism activity.
More detailed discussions of the characteristics and performance
of each of the above-mentioned biological treatment systems, and
also for common combinations of them, are described below.
Capital and operating costs are discussed in Section VIII.
Anaerobic Processes
The warm waste water temperatures (20° to 31°C, or 68° to 88°F)
and high concentrations of carbohydrates, fats, proteins, and
97
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nutrients which characterize most poultry processing plant wastes
make these wastes suited to anaerobic treatment. Anaerobic or
facultative microorganisms, which function in the absence of
dissolved oxygen, break down the organic wastes to intermediates
such as organic acids and alcohols. Methane bacteria then
convert the intermediates primarily to carbon dioxide and
methane. Unfortunately, much of the organic nitrogen present in
the influent is converted to ammonia nitrogen. Also, if sulfur
compounds are present (such as from high-sulfate raw water—50 to
100 mg/1 sulfate), hydrogen sulfide will be generated. Acid
conditions are undesirable because methane formation is
suppressed and noxious odors develop. Anaerobic processes are
economical because they provide high overall removal of BODI5 and
suspended solids with no power cost (other than pumping) and with
low land requirements. Two types of anaerobic processes are
used: anaerobic lagoons and anaerobic contact systems.
Anaerobic Lagoons
Anaerobic lagoons are in common use in the poultry processing
industry as the first step in biological treatment or as
pretreatment prior to discharge to a municipal system.
Reductions of up to 97-percent in BOD5 and up to 95-percent in
suspended solids can te achieved with the lagoons; 85-percent
reduction is common. Occasionally two anaerobic lagoons are used
in parallel and sometimes in series. These lagoons are
relatively deep (3 to 5 meters, or about 10 to 17 feet), low
surface-area systems with typical waste loadings of 240 to 320 kg
BOD5/1000 cubic meters (15 to 20 lb BOD5/1000 cubic feet) and
detention times of five to ten days.
Plastic covers of nylon-reinforced Hypalon, polyvinyl chloride
and styrofoam have been used on occasion by other industries in
place of a scum layer; in fact, some States require this, A scum
layer may be used to retard heat loss, to insure anaerobic
conditions, and hopefully to retain obnoxious odors. Properly
installed covers provide a convenient means for odor control and
collection of the byproduct methane gas.
The waste water flow inlet should be located near, but not on,
the bottom of the lagoon. In some installations, sludge is
recycled to insure adequate anaerobic seed for the influent. The
outlet from the lagoon should be located to prevent short
circuiting of the flow and carry-rover of the scum layer.
For best operation, the pH should be between 7.0 and 8.5. At
lower pH, methane-forming bacteria will not survive and the acid
formers will take over to produce very noxious odors. At a high
pH (above 8.5), acidforming bacteria will be suppressed and lower
the lagoon efficiency.
98
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Advantages-Disadvantages
Advantages of an anaerobic lagoon system are initial low cost,
ease of operation, and the ability to handle larqe grease loads
and shock waste loads, and yet continue to provide a consistent
quality effluent.2* Disadvantages of an anaerobic lagoon are the
hydrogen sulfide generated from sulfate-containing waters and the
typically high ammonia concentrations in the effluent of 100 mg/1
or more. If acid conditions develop, severe odor probiems
result. Incidentally, if the gases evolved are contained, it is
possible to use iron filings to remove sulfides.
Applications
Anaerobic lagoons used as the first stage in biological treatment
are usually followed by aerobic lagoons. Placing a small,
mechanically aerated lagoon between the anaerobic and aerobic
lagoons is becoming popular. A number of meat packing plants are
currently installing extended aeration units following the
anaerobic lagoons to obtain nitrification. Anaerobic lagoons are
not permitted in some States or areas where the ground water is
high or the soil conditions are adverse (e.g., too porous) or
because of odor problems.
99
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Aerated Lagoons
Aerated lagoons have been used successfully for many years in a
modest number of installations treating meat packing and poultry
processing plant wastes. However, with the tightening of
effluent limitations, and because aerated lagoons can provide
additional treatment and enhance beneficial biological activity
in aerobic lagoons (otherwise) receiving an anaerobic influent,
the number of installations is increasing.
Aerated lagoons use either fixed mechanical turbine-type
aerators, floating propeller-type aerators, or a diffused air
system for supplying oxygen to the waste water. The lagoons
usually are 2.4 to 4.6 meters (8 to 145 feet) deep, and have a
detention time of two to ten days. BOD5 reductions range from 40
to 60 percent, with little or no reduction in suspended solids.
Because of this, aerated lagoons approach conditions similar to
extended aeration without sludge recycle (see below).
Advantages-Disadvantages
Advantages of this system are that it can rapidly add dissolved
oxygen (DO) to convert anaerobic effluent to an aerobic state; it
provides additional BODJ3 reduction; and it requires a relatively
small amount of land. Aeration is of particular importance both
as a means to assure that aerobic lagoons get a "head start" in
aerobic digestion, and as a process which stabilizes fluctuations
in performance in anaerobic systems. Disadvantages include the
power requirements and the fact that the aerated lagoon, in
itself, usually does not reduce BODj> and suspended solids
adequately to be used as the final stage in a high performance
biological system.
Applications
Aerated lagoons are usually the first or second stages of
biological treatment, and must be followed by aerobic (shallow)
lagoons to reduce suspended solids and to provide the required
final treatment.
Aerobic Lagoons
Aerobic lagoons (stabilization lagoons or oxidation ponds) are
large surface area, shallow lagoons, usually 1 to 2.3 meters (3
to 8 feet) deep, loaded at a BOD5 rate of 20 to 50 pounds per
acre. Detention times vary from about one month to six or seven
months; thus, aerobic lagoons require large areas of land. Use
of a series of these lagoons (with or without supplemental
aeration) virtually assures sustenance of the bacteriological
activity necessary for efficient biological treatment under even
the harshest climatic conditions.
100
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Aerobic lagoons serve three main functions in waste reduction;
o Allow solids to settle out;
o Equalize and control flow;
o Permit stabilization of organic matter by aerobic anfi
facultative microorganisms and also by algae.
Actually, if the pond is quite deep, 1.8 to 2.4 meters (6 to 8
feet), the waste water near the bottom may be void of dissolved
oxygen and anaerobic organisms may be present. Therefore,
settled solids can be decomposed into inert and soluble organic
matter by aerobic, anaerobic, or facultative organisms, depending
upon the lagoon conditions. The soluble organic matter is also
decomposed by microorganisms. It is essential to maintain
aerobic conditions in at least the upper six to twelve inches in
shallow lagoons, since aerobic microorganisms cause the most
complete removal of organic matter. Wind action assists in
carrying the upper layer of liquid (aerated by air-water
interface and photosynthesis) down into the deeper portions. The
anaerobic decomposition generally occurring in the bottom
converts solids to liquid organics, which can become nutrients
for the aerobic organisms in the upper zone.
Algae growth is common in aerobic lagoons; this may be a drawback
when aerobic lagoons are used for final treatment because tha
algae will appear as suspended solids and contribute BOD5. Algae
added to receiving waters .are thus considered a pollutant. Algae
in the effluent may be reduced by drawing off the lagoon effluent
at least 30 cm (about 14 inches) below the surface where
concentrations are usually lower, periodic maintenance cleaning
of the lagoon, installation of small clarifier, or a combination
of these actions. Algae in the lagoon, however, play an
important role in stabilization. They use CO2, sulfates,
nitrates, phosphates, water and sunlight to synthesize their own
organic cellular matter and give off oxygen. The oxygen may then
be used by other microorganisms for their metabolic processes.
However, when algae die they release their organic matter in th
-------
is no ice and snow cover on large aerobic lagoons, high winds can
develop a strong wave action that can damage dikes. Riprap,
segmented lagoons, and finger dikes are used to prevent wave
damage. Finger dikes, when arranged appropriately, also prevent
short circuiting of the waste water through the lagoon. Rodent
and weed control, and dike maintenance are all essential tor good
operation of the lagoons.
Advantages-Disadvantages
Advantages of aerobic lagoons are that they reduce the suspended
solids and colloidal matter, and oxidize the organic matter of
the influent to the lagoon; they also permit flow control and
waste water storage. Disadvantages are reduced effectiveness
during winter months that may require extended "no discharge"
detention periods (90 days or more), the large land requirements,
a possibility for excessive algae for which counter measures may
be required, and odor problems for a short time in spring, after
the ice melts and before the lagoon becomes aerobic again.
Appli cation s
Aerobic lagoons usually are the last stage in biological
treatment and frequently follow anaerobic or anaerobic-plus-
aerated lagoons. Large aerobic lagoons allow plants to store
waste waters for discharge during periods of high flow in the
receiving body of water or to store for irrigation purposes
during the summer. These lagoons are particularly popular in
rural areas where land is available and relatively inexpensive.
Activated Sludge
The conventional activated sludge process is schematically shown
in Figure 12. In this process, recycled, biologically active
sludge or floe is mixed in aerated tanks or basins with waste
water. The microorganisms in the floe adsorb organic matter from
the wastes and convert it by oxidation-enzyme systems to such
stable products as carbon dioxide, water, and sometimes nitrates
and sulfates. The time required for digestion depends on the
type of waste and its concentration, but the average time is six
hours. The floe, which is a mixture of microorganisms (bacter,
protozoa, and filamentous types), food, and slime material, can
assimilate organic matter rapidly when properly activated; hence,
the name activated sludge.
From the aeration tank, the mixed sludge and waste water, in
which little nitrification has taken place, are discharged to a
sedimentation tank. Here the sludge settles out, producing a
clear effluent, low in BODjj, and a biologically active sludge. A
portion of the settled sludge, normally about 20 percent, is
recycled to serve as an inoculum and to maintain a high mixed
liquor suspended solids content. Excess sludge is removed
102
-------
o
i-o
Raw
Waste
Primary
Sedimentation
Secondary
Sedimentation
Aeration Tank
Activated
Effluent
Waste
Sludge
Waste I
Sludge^
Figure 12. Activated Sludge Process
-------
(wasted) from the system, to thickeners and anaerobic digestion,
to chemical treatment and dewatering by filtration or
centrifugation, or to land disposal where it is used as
fertilizer and soil conditioner to aid biological crop growth.
This conventional activated sludge process can reduce BOD5 and
suspended solids up to 95 percent. However, it cannot readily
handle shock loads and widely varying flows and therefore might
require upstream flow equalization.
Various modifications of the activated sludge process have been
developed, such as the tapered aeration, step aeration, contact
stabilization, and extended aeration. Of these, extended
aeration processes are most frequently being used for treatment
of meat processing, meat packing, poultry processing, and
rendering wastes.
Extended Aeration
The extended aeration process is similar to the conventional
activated sludge process, except that the mixture of activated
sludge and raw materials is maintained in the aeration chamber
for longer periods of time. The usual detention time in extended
aeration ranges from one to three days, rather than six hours as
in the conventional process. During this prolonged contact
between the sludge and raw waste, there is ample time for the
organic matter to be adsorbed by the sludge and also for the
organisms to metabolize the organic matter which they have
adsorbed. This allows for a much greater removal of organic
matter. In addition, the organisms undergo a considerable amount
of endogenous respiration, and therefore oxidize much of the
organic matter which has been built up into the protoplasm of the
organism. Hence, in addition to high organic removals from the
waste waters, up to 75 percent of the organic matter of the
microorganisms is decomposed into stable products, and
consequently less sludge will have to be handled.
In extended aeration, as in the conventional activated sludge
process, it is necessary to have a final sedimentation tank.
Some of the solids resulting from extended aeration are rather
finely divided and therefore settle slowly, requiring a longer
period of settling.
The long detention time in the extended aeration tank makes it
possible for nitrification to occur. In nitrification under
aerobic conditions, ammonia is converted to nitrites and nitrates
by specific groups of nitrifying bacteria. For this to occur, it
is necessary to have sludge detention times in excess of ten
days.21 This can be accomplished by regulating the amounts of
recycle and wasted sludge. Oxygen-enriched gas could be used in
place of air in the aeration tanks to improve overall
performance. This would require that the aeration tank be
partitioned and covered, and that the air compressor and
dispersion system be replaced by a rotating sparger system. When
concurrent, staged flow and recirculation of gas back through the
104
-------
liquor are employed, between 90 and 95-percent oxygen use is
claimed. Although this modification of extended aeration has not
been used in treating poultry processing plant wastes, it is
being used successfully for treatment of other wastes.
Advantages-Disadvantages
The advantages of the extended aeration process are that it is
immune to shock loading and flow fluctuations because the
incoming raw waste load is diluted by the liquid in the system to
a much greater extent than in conventional activated sludge.
Also, because of the long detention time, high BOD5 reductions
can be obtained. Other advantages of the system are the
elimination of sludge digestion equipment and the capability to
produce a nitrified effluent. Disadvantages are that it is
difficult to remove most of the suspended solids from the mixed
liquor discharged from the aeration tank; large volume tanks or
basins are required to accommodate the long detention times; and
operating costs for aeration are high.
Applications
Because of the nitrification process, extended aeration systems
are being used by some industries following anaerobic processes
or lagoons to produce low BOD^ and low ammonia-nitrogen
effluents. They are also being used as the first stage of
biological treatment, followed by polishing lagoons.
Rotating Biological Contactor
Process Description
The rotating biological contactor (RBC) consists of a series of
closely spaced flat parallel disks which are rotated while
partially immersed in the waste waters being treated. A
biological growth covering the surface of the disk adsorbs
dissolved organic matter present in the waste water. As the
biomass on the disk builds up, excess slime is sloughed off
periodically and is settled out in sedimentation tanks. The
rotation of the disk carries a thin film of waste water into the
air where it absorbs the oxygen necessary for the aerobic
biological activity of the biomass. The disk rotation also
promotes thorough mixing and contact between the biomass and the
waste waters. In many ways the RBS system is a compact version
of a trickling filter. In the trickling filter, the waste waters
flow over the media and thus over the microbial flora; in the RBC
system, the biological medium is passed through the waste water.
The system can be staged to enhance overall waste load reduction,
Organisms on the disks selectively develop in each stage and are
thus particularly adapted to the composition of the waste in that
stage. The first stages might be used for removal of dissolved
105
-------
organic matter, while the latter stages might be adapted to
nitrification of ammonia.
Development Status
The RBC system was developed independently in Europe and the
United states about 1955 for the treatment of domestic waste; it
found application only in Europe, where there are an estimated
1,000 domestic installations,21 However, the use of the RBC for
the treatment of poultry processing waste is being evaluated at
the present time. One poultry plant1* is reported to have
obtained a 90-percent BOD5 reduction (from 2,000 to 200 mg/1)
when treating the effluent from an air flotation system. Pilot
scale operating information is available on its use on meat
packing waste. The pilot-plant studies were conducted with a
four-stage RBC system with four-foot diameter disks* The system
was treating a portion of the effluent from the Austin,
Minnesota, anaerobic contact plant used to treat meat packing
waste. The results showed a BOD5 removal in excess of 50
percent, with loadings less than 0.037 kg BOD5 per square meter
on an average BOD5 influent concentration of approximately 25
mg/1, 2 2
Data from Autotrol Corporation, one of the suppliers of RBC
systems, revealed ammonia removal of greater than 90 percent by
nitrification in a multistage unit. Four to eight stages of
disks with maximum hydraulic loadings of 61 liters per day per
square meter (1.5 gallons per day per square foot) of disk area
are considered normal for ammonia removal.
A large installation was recently completed at the Iowa Beef
Processors plant in Dakota City, Nebraska, for the further
treatment of the effluent from an anaerobic lagoon.23 No data
are available on this installation, which has been plagued with
mechanical problems.
Advantages-Pi sadvantaqes
The major advantages of the RBC system are its relatively low
first cost; the ability to obtain dissolved organic matter
reduction with the potential for removal of ammonia by
nitrification; and its good resistance to hydraulic shock loads.
Disadvantages are that the system should be housed, if located in
cold climates, to maintain high removal efficiencies and to
control odors. This system has demonstrated its durability and
reliability when used on domestic wastes in Europe, and is
currently being tested on poultry processing plant wastes in this
country-
106
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Uses
Rotating biological contactors could be used for the entire
aerobic biological system. The number of stages required depend
on the desired degree of treatment and the influent strength.
Typical applications of the rotating biological contactor,
however, may be for polishing the effluent from anaerobic
processes, and as pretreatment prior to discharging wastes to a
municipal system. A BOD5 reduction of 98 percent is reportedly
achievable with a four-stage
ADVANCED WASTE TREATMENT
Chemical Precipitation
Phosphorus is an excellent nutrient for algae and thus can
promote heavy algae blooms. As such, it cannot be discharged
into receiving streams, and its concentration should not be
allowed to build up in a recycle water stream. However, the
presence of phosphorus is particularly useful in spray or flood
irrigation systems as a nutrient for plant growth.
The effectiveness of chemical precipitation for removing
phosphorus. Figure 13, has been verified in full-scale during the
North Star verification sampling program of the meat packing
industry.19 One packing plant operates a dissolved air flotation
system as a chemical precipitation unit and achieves 95-percent
phosphorus removal, to a concentration of less than 1 mg/1.
Chemical precipitation can be used for primary (in-plant)
treatment to remove BOD5, suspended solids, and grease, as
discussed earlier in conjunction with dissolved air flotation.
Also, it can be used as a final treatment following biological
treatment to remove suspended solids in addition to phosphorus.
Technical Description
Phosphorus occurs in waste water streams from poultry processing
plants primarily as phosphate salts. Phosphates can be
precipitated with trivalent iron and trivalent aluminum salts.
It can also be rapidly precipitated by the addition of lime;
however, the. rate of removal is controlled by the agglomeration
of the precipitated colloids and by the settling rate of the
agglomerate.15 Laboratory investigation and experience with in-
piant operations have substantially confirmed that phosphate
removal is dependent on pH and that this removal tends to be
limited by the solubility behavior of the three phosphate salts —
calcium, aluminum, and iron. The optimum pH for the iron and
aluminum precipitation occurs in the 4 to 6 range, whereas the
calcium precipitation occurs on the alkaline side at pH values
above 9.5^ **
Since the removal of phosphorus is a two-step process involving
precipitation and then agglomeration, and both are sensitive to
107
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pH, controlling the pH level takes on added significance. If a
chemical other than lime is used in the precipitation/coagulation
process, two levels of pH are required. Precipitation occurs on
the acid side and coagulation is best carried out on the alkaline
side. The precipitate is removed by sedimentation or by
dissolved air flotation.
Polyelectrolytes are polymers that can be used as primary
coagulants, flocculation aids, filter aids, or for sludge
conditioning. Phosphorus removal may be enhanced by the use of
such polyelectrolytes by producing a better floe than might occur
without such chemical addition. z*
The chemically precipitated sludge contains grease and organic
matter in addition to the phosphorus, if the system is used in
primary treatment. If it is used as a post-biological treatment,
the sludge volume will be less and it will contain primarily
phosphorus salts. The sludge from either treatment can be
landfilled.
Development Status
This process is well established and understood, technically.
However, its use on poultry processing plant waste waters,
normally as a primary waste treatment system, is limited;
although, its use may grow as more stringent effluent limitations
are imposed.
Problems and Reliability
As indicated above, the reliability of this process is well
established; however, it is a chemical process and as such
requires the appropriate control and operating procedures. The
problems that can be encountered in operating this process are
frequently the result of a lack of understanding or inadequate
equipment. Sludge disposal is not expected to be a problem,
although the use of polyelectrolytes and their effect on the
dewatering properties of the sludge are open to some question at
the present time. In addition, the use of the recovered sludge
as a raw material for rendering may be less desirable as a result
of chemical addition.
Sand Filter
A slow sand filter is a specially prepared bed of sand or other
mineral fines on which doses of waste water are intermittently
applied and from which effluent is removed by an under-drainage
system (Figure 14); it removes solids from the waste water
stream. A variety of filters can be used to remove the solids in
a treated wastewater: intermittent sand filters, slow sand
filters, rapid sand filters, and mixed-media filters, BOD5
removal occurs primarily as a function of the degree of solids
removal. The effluent from the sand filter is of a high quality.
108
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Float
Primary
or
oeconoary •?
Treatment
Effluent
pH
Ajustment
Chemical
Addition
N
/
^
Air
Flotation
System
Partial
ireatea
Effluent
V
Sludge
to
Disposal
Figure 13. Chemical Precipitation
Primary or
Secondary
Treatment
Effluent
Dosing
Tank
Chlorination,
Optional
for Odor Control
Filter
A
V
V
Surface Back
Clean u Wash
to Regenerate
> Treated
Effluent
Figure 14. Sand Filter Syst
em
-------
A summary of available information indicates that effluent
suspended solids concentrations of less than 10 mg/1 can be met.
Although the performance of a sand filter is well known and
documented, it is not in common use in the meat products industry
because use of refinements of this type has not been needed to
reach current waste water limitations.
A rapid sand filter may operate under pressure in a closed vessel
or may be built in open concrete tanks. It is primarily a water
treatment device and thus would be used as advanced treatment.
Mixed-media filters are special versions of rapid sand filters
that permit deeper bed-penetration by gradation of particle sizes
in the bed. Up-flow filters are also special cases of rapid
filters.
Technical Description
The slow sand filter removes solids primarily at the surface of
the filter. The rapid sand filter is operated to allow a deeper
penetration of suspended solids into the sand bed and thereby
achieve solids removal through a greater cross section of the
bed. The rate of filtration of the rapid filter is up to 100
times that of the slow sand filter. Thus, the rapid filter
requires substantially less area than the slow filter; however,
the cycle time averages about 2H hours in comparison with cycles
of up to 30 to 60 days for a slow filter,26 The larger area
required for the latter means a higher first cost. For small
plants, the slow sand filter can be used as advanced treatment.
The rapid sand filter, on the other hand, can be more generally
applied following biological treatment. However, if used as
biological treatment it would tend to clog quickly and require
frequent backwashing, resulting in a high water use. This wash
water would also need treatment prior to discharge particularly
it the rapid sand filter were used in biological treatment
applications with only conventional solids removal upstream in
the plant.
The rapid filters operate essentially unattended with pressure
loss controls and piping installed for automatic backwashing.
They are contained in concrete structures or in steel tanks.
In a rapid sand filter, as much as 80 percent of the head loss
can occur in the upper few inches of the filter. One approach to
increase the effective filter depth is the use of more than one
media in the filter. Other filter media have included coarse
coal, heavy garnet or ilmenite media, and sand.2* There is no
one mixed media design which will be optimum for all wastewater
filtration problems. As an example, "removal of small quantities
of high-strength biological floe often found in activated sludge
effluents may be satisfactorily achieved by a good dual media
design. With a weaker floe strength or with an increase in
applied solids loading, the benefits of the mixed, tri-media bed
become more pronounced.nz*
110
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Although a mixed-media filter can tolerate higher suspended
solids loadings than can other filtration processes, it still has
an upper limit of applied suspende
-------
Table 14.*. rffluent- Oualitv from Conventional
filtration of Carious THologicailv Treated Wa
Influent
Source
Activated F!ludcro
Activated Sludae
"xtended
Deration plus
settling
Trickling
^ilter
Activated Sludge
with Clarifier
Contact
Stabilisation
(ra*T waste
includes
cannerv)
miscellaneous
rilter
TYPE
nrvwit"
mixed, media
multi-media
pressure,
multi-media
nravitv,
sand
multi-media
mixed media
sand
(S!CT-* and
ran id)
nilter Influent (mg/1)
BOD TSS
15-20 10-25
11-50 28-126
7-36 30-2180
15-130 8-75
18
(AVE)
_ —
10-50 15-75
'liter 'Pf fluent (mq/1) Reference
pnn. TSS
4-3 0 2-5 70
3-3 1-17 70
1-4 1-20 70
2-74 " 1-27 ^3, 65
2.4 67
(AVE)
2-4 2-8 68
2-6 3-10 62, 64,
73
Trickling
pilter v\i
Nitrification
sand
3-7
57
*See also, irerformance data in references 24, 25, 65, 66, and
-------
Problems and Reliability
The reliability of all principal types ot filters seems to be
well established by lonq-term use as a municipal waste treatment
system. When the sand filter is operated intermittently there
should be little danger of operating mishap with resultant
Discharge of untreated effluent or poor quality effluent. The
need for bed cleaning becomes evident with the reduction in
quality of the effluent or in the increased cycle time, both of
which are subject to monitoring and control. Operation in cold
climates is possible as long as the appropriate adjustment in the
surface of the bed has been made to prevent the bed from clogging
due to freezing water.
With larger sized slow sand filters, the labor in maintaining and
cleaning the surface should receive adequate consideration.
Cleanup of the rapid sand filter requires backwashing of the bed
of sand with a greater quantity of water than used for the slow
sand filter. Backwashing is an effective cleanup procedure and
the only constraint is to minimize the washwater required in
cleanup, since this must be disposed of in some appropriate
manner other than discharging it to a stream, Chlorination, both
before and after sand filtering, particularly in the use of rapid
filters, may be desirable to minimize or eliminate potential odor
probleirs and slimes that may cause clogging.
The rapid sand filter has been used extensively in water
treatment plants and in municipal sewage treatment for advanced
treatment; thus, its use in advanced treatment of biological
treated effluents from poultry processing plants appears to be a
practical method of reducing EOD5 and suspended solids to levels
below those expected from conventional biological treatment.
Microscreen-Microstrainer
A microstrainer is a filtering device that uses a fine mesh
screen on a partially submerged rotating drum to remove suspended
solids and thereby reduce the BODjS associated with those solids,
as shown in Figure 15. The microstrainer is used as a advanced
treatment following the removal of most of the solids from the
waste water stream, and suspended solids and BOD5 have been
reduced to 3 to 5 mg/1 in applications on municipal waste.IS As
mentioned earlier, one poultry processing plant using
microscreens as advanced treatment consistently achieved a BOD5
in the effluent of less than 15 mg/1 and frequently below 5 mg/1.
The effluent quality obtained by the microstrainer at the poultry
processing plant is consistent with data reported by other
situations in which micrcstrainers have been used to remove
solids from biological effluents. The percent removal of
suspended solids by a microstrainer are related to the size of
the aperture of the screen. Fifty to 60-percent removals can be
anticipated with a 23-micron strainer and 40 to 50-percent
removals with a 35-micron strainer.24 The microstrainer effluent
quality from a number of studies indicated suspended solids
113
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Secondary
Treatment
Effluent
Micro-
Screen
v
f
Bo<
ckwash
Clear
to
Screen/Strainer
Tertiary
Effluent
Figure 15. Microscreen/Microstrainer
-------
concentrations of 6 to 8 mg/1 when activated sludge effluent was
tested, and 15 to 40 mg/1 when a trickling filter effluent was
treated.z*
Technical De scription
The microstrainer is a filtration device in which a stainless
steel microfabric is used as the filtering medium. The steel
wire cloth is mounted on the periphery of a drum which is rotated
partially submerged in the waste water. Backwash immediately
follows the deposition of solids on the fabric, and in one
installation, this is followed by ultra-violet light exposure to
inhibit microbiological growth. The backwash water containing
the solids amounts to about 3 percent of the waste water stream
and must be disposed of by recycling to the biological treatment
system.28 The drum is rotated at a minimum of 0.7, and up to a
maximum of 4.3 revolutions per minute. The concentration and
percentage removal performance for microstrainers on suspended
solids and BODji appear to be approximately the same as for sand
filters.
Development Status
While application of microscreens for filtration is more recent
than that of conventional filters, there is general information
available on the performance of microstrainers and on tests
involving the use of them. In addition to its use on poultry
processing waste, there has been a substantial increase in full-
scale applications at municipal facilities. As with conventional
filters, the requirements for effluent quality have not
necessitated such installations in the past. The economic
comparisons between sand filters and microstrainers are
inconclusive; the mechanical equipment required for the
microstrainer may be a more relevant factor than the space
requirement for the sand filter at the present time. Table 14B
provides a brief summary of the general performance achieved by
microstrainers on biologically treated wastewater.
Problems and Reliability
The reported performance of the microstrainer fairly well
establishes the reliability of the device and its ability to
remove suspended solids and associated BODf>. operating and
maintenance problems have not been reported; this is probably
because, in large part, of the limited use of the device in full-
scale applications. As a mechanical filtration device requiring
a drive system, it would have normal maintenance requirements
associated with that kind of mechanical equipment. As a device
based on microopenings in a fabric, it would be particularly
intolerant to any substantial degree of grease loading.
115
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Table 14B. Performance of Microstrainers
in Tertiary Treatment of Biologically Treated Wastewater
Influent (mg/1) Effluent (mg/1) Reference
BOD
15-20
10-30
-
15-25
TSS
20-25
10-40
6-54
15-30
BOD
3-5
3-8
-
4-5
TSS
6-8
3-10
2-14
3-7
24
73
70*
poultry pi a
*Data from 22 municipal installations including several with
wasteload contributions from unidentified industrial sources.
116
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Nitrogen control
Nitrification
Nitrification is the biological conversion of nitrogen in organic
or inorganic compounds from a more reduced to a more oxidized
state. In the field of water pollution control, nitrification
usually is referred to as the process in which ammonium ions are
oxidized to nitrite and nitrate sequentially. When aeration
systems are used to treat an industrial wastewaterr some
nitrification and ammonia stripping can be expected to occur
naturally and thus reduce the quantity of ammonia requiring
further removal. This "incidental" treatment has been observed
for treated effluents from several types of meat products plants
where concentrations of about 10 to 50 wg/1 of ammonia have been
found, while partially treated wastes have concentrations in
excess of 100 mg/1. Ammonia removal is becoming more important
since it is recommended that the concentration of un-ionized
ammonia (NH3) in surface water be no greater than 0.02 mg/1 at
any time or place. Because ammonia may be indicative of
pollution, it is recommended that ammonia nitrogen in public
water supply sources not exceed 1.5 mg/1.*2
Technical Description
Nitrification can be used to reduce the ammonia concentration of
wastewaters. Figure 16 is a schematic of the nitrification
process. The equations following the figure indicate the
nitrification sequence and organisms involved.
Adequate process design and operating control are necessary for
consistent results. Factors that affect the nitrification
process include concentration of nitrifying organisms,
temperature, pH, dissolved oxygen concentration, and the
concentration of any inhibiting compounds.*3 The nitrifying
organisms of significance in waste management are autotrophic,
with Nitrosomes and Nitrobacter being the major bacterial genera
that are involved. Nitrifying bacteria are ubiquitous in the
soil although they may not be part of untreated wastes.
Nitrifying organisms are aerobic and adequate dissolved oxygen
(DO) in the aeration system is necessary. DO concentrations
should be above 1 to 2 mg/1 to assure consistent nitrification.
Nitrification is affected by the temperature of the system.
Available information provides conflicting data on the
performance of nitrification systems at low temperatures.
117
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00
Secondary
Treatment
Effluent
Aeration
System
i
\ "
Anaerobic ,
Pond *
Aeration ^ Tertiary
Cell > Treated
Effluent
Carbon
Source,
e.g. Methanol
Figure 16. Nitrification/Denitrification
Nitrification:
NH3 + 02
2N02~ + 02
N02~ + H30 (Nitrosomonas)
2NO " (Nitrobacter)
Denitrification (using methanol as carbon source)
6H + 6N03~ + 5CH3OH
5C02 + 3N2 + 13H20
Small amounts of N20 and NO are also formed
(Facultative heterotrophs)
-------
Although detailed studies are lacking, it should be possible to
achieve nitrification at low temperatures and compensate for
slower nitrifying organism growth rates by maintaining a longer
solids detention time and hence larger nitrifying active mass in
the system.**
The optimum pH for nitrification of municipal sewage has been
indicated to be between 7.5 and 8.5. Nitrification can proceed
at low pH levels but at less than optimum rates. During
nitrification, hydrogen ions are produced and the pH decreases,
the magnitude of the decrease being related to the buffer
capacity of the system. A decrease in pH is a practical measure
of the onset of nitrification.
High concentrations of un-ionized ammonia (NH3) and un-ionized
nitrous acid (H N02) can inhibit nitrification. These compounds
can be in the influent wastewater or can be generated as part of
the nitrification process. The concentrations of un-ionized
ammonia and nitrous acid that are inhibitory; and, the
operational approaches to avoid such inhibition have been
documented.** Using these approaches, it should be possible to
operate nitrification systems that produce consistent results
even with wastewaters having high nitrogen concentrations.
Development status
While research on nitrification has been conducted for a
number of years, most pilot and full-scale studies have been
initiated since 1970. Even though there has been a relatively
short time frame of evaluation, nitrification is already a very
readily described process for which treatment system designs can
be implemented. Most of the applications have been on municipal
effluents, but concentrations of ammonia in these effluents
ranged between 20 mg/1 and 800 mg/1. Ammonia concentrations in
biologically treated effluents from various types of meat and
poultry packing and processing plants have been found to range
between 10 mg/1 and 200 mg/1 or more, and thus fall within the
limits of the nitrification investigations cited below in Table
14C. Like any other "advanced" level of treatment, nitrification
requires more operational attention than has generally been given
to simple biological treatment, but the applicability of the
process to all types of meat product effluents appears very
reasonable.
Problems and Reliability
As discussed above, emphasis on nitrification as a treatment
process has been relatively recent. Except for incidental
ammonia removal facilities, nitrification processes have not been
specifically applied in this industry. A pilot facility may be
necessary to derive design and operating requirements before any
full-scale installations are constructed. Water temperature,
particularly below 10°C, is an apparent constraint for which an
increase in sludge age or solids retention time (via sludge
recycle) has been shown to compensate. Maintenance of adequate
119
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14r. Selected "esults for
Nitrogen Control—
'•'ode
Extented aeration (N)
Clarification (ON)
Denitrif ication "Hewer
Nitrification
Single ?tage (DM)
Rotating nisc(N)
Trickling rilter Totter (N)
derated sludge and
anaerobic reactor (ON)
Breakpoint 00
chlorination
Activated Sludge (H)
Parameter (s)
Measured
Total Kjeldahl
Nitrogen
Tx>tal nitroaen
Armenia
Anmonia
Total nitrogen
Ammonia
Armonia
nitrates
Arrroonia
Aimonia
Tf fluent
Toncentration (mg/1)
0.5-10.0
5.0
0.8-1.2
1.7 June-
1.9 Januarv
3.8-5.9
0.3-1.2
1.6-2.5
1.2-1.9
0.0-1.5
0.0
1.0
0.0-2.7
60
47
47
47
47
57£/
53
71
72
—''Jote (N) refers to nitrification svsten and (DN) refers to nitrification-
denitrification
li'Influent anmonia concentrations ranae of 450-800 nq/1
£'"*anqe of data for 18 month neriod; test site in Michigan with seasonal
data collected for annroximatelv two T-teeks each season.
-------
dissolved oxygen levels is also important since nitrification
activity effectively ceases at DO levels below 1.0 mg/1., The
process is relatively delicate and should require attentive
operation,
Nitrification/Denitrification
This two-step process of nitrification and denitrification,
Figure 16, is of primary importance for removal of the residual
ammonia and nitrites-nitrates in biological treatment systems.
Removal of the above soluble nitrogen forms is virtually
complete, with the nitrogen gas as the end product. This process
differs from ammonia stripping and nitrification in that the
latter processes convert or remove only the ammonia content of a
wastewater. Table me shows a summary of results in removing
both ammonia and other nitrogen from wastewaters.
Technical Description
As described in an earlier section, nitrification is carried out
under controlled process conditions by aerating the wastewater
sufficiently to assure the conversion of the nitrogen in the
wastewater to the nitrite-nitrate forms. The denitrification
process reduces the oxidized nitrogen compounds (nitrites and
nitrates) to nitrogen gas and nitrogen oxides thereby reducing
the nitrogen content of the wastewater as the gases escape from
the liquid.
Denitrification takes place in the absence of dissolved oxygen.
Additional important factors affecting denitrification include
carbon source, and temperature. Denitrification is brought about
by heterotrophic facultative bacteria. Generally, high
denitrification rates require the addition of a biodegradable
carbon source such as sugar, ethyl alcohol, acetic acid, or
methanol. Methanol is the least expensive and performs
satisfactorily. Investigators working on this process have found
that a 30-percent excess of methanol over the stoichiometric
amount is required.2*,30
Denitrification does not take place until the dissolved oxygen
concentration of the wastewater is near or at zero. The
organisms responsible for denitrification are ubiquitous and can
adapt to pH levels within the range of about 6.0 to 9.0. As with
any biochemical process, denitrification exhibits a temperature
dependency, although within the range of 20°C to 30°C little
effect has been observed. Denitrification activity decreased
when the temperature decreased to 10°C. Denitrification can be
operated at low temperatures by designing systems with long
solids retention times (SRT). For denitrification systems, an
SRT of at least 3 to a days at 20°C and 30°C and 8 days at 10°C
has been recommended.*3 Nitrate reduction efficiency in
denitrification can be controlled by adjusting the SRT of the
process to assure adequate numbers of denitrifying organisms and
adequate denitrification rates as environmental conditions
change.
121
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In a sequential nitrification/denitrification process (Figure
16) , the wastewater from the denitrification step may be sent to
a second aeration basin following denitrification, where the
nitrogen and nitrogen oxide are readily stripped from the waste
stream as gases. The sludge from each stage is settled and re-
cycled to preserve the organisms required for each step in the
process. The processes of nitrification and denitrification can
occur simultaneously in aeration systems in which both aerobic
and anaerobic portions occur.
Development Status
Nitrification/denitrification has not been applied to poultry
processing wastewaters as yet. The process has been evaluated in
a number of bench and pilot-scale studies on a variety of wastes.
Further demonstration on a plant scale will establish the
potential of the process.43,*5 Anaerobic processes evaluated as
part of the denitrification sequence have included anaerobic
ponds, an anaerobic activated sludge system, and anaerobic
filters. Efficient nitrogen removals from agricultural
subsurface drainage water were accomplished with an anaerobic
filter. In Germany, the successful elimination of nitrogen from
sewage and digester supernatant was achieved by first nitrifying
the wastes and then denitrifying in a separate vessel. Two and
three sludge systems have been shown to be feasible for the
nitrification/denitrification process. A pilot model of a three-
stage system using this process was developed at the Cincinnati
Water Research Laboratory of the EPA and is being built at
Manassas, Virginia.31 Observations of treatment lagoons indicate
that the suggested reactions are occurring in present systems.
Also, Halvorson32 reported that Pasveer achieved success in de-
nitrification by carefully controlling the reaction rate in an
oxidation ditch, so that dissolved oxygen levels drop to near
zero just before the water is reaerated by the next rotor.
Denitrification of animal wastes has been evaluated and shown to
be feasible,43 *s Depending upon how a biological system such as
an oxidation ditch is operated, the nitrogen loss can range from
30 to about 90 percent.**
Problems and Reliability
It would appear that there would be no exceptional maintenance or
residual pollution problems associated with this process in view
of the mechanisms suggested for its implementation at this time.
For some of the newer concepts, i.e., denitrification by
fluidized bed reactors, operational difficulties due to
biological matting of the carbon filter bed have been encountered
in bench scale tests. These difficulties may prove negligible
under field conditions, since continuing new inputs of biota
would enhance the likelihood of a balance in growth factors.
Completely mixed reactors with methanol addition appear to be
favored from the standpoints of operational control and long-term
reliability in nitrogen removal. However, a final aeration
122
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chamber may be required to offset increases in effluent BOD due
to methanol leakage from the denitrification reactor. As with
nitrification, sludge return has also been shown to assist system
stability in the denitrification mode.47
Ammonia Stripping
Ammonia stripping is a physical process and amounts to a
modification of the simple aeration process for removing gases in
water. Figure 17. Following pH adjustment, the waste water is
fed to a packed tower and allowed to flow down through the tower
with a countercurrent air stream introduced at the bottom of the
tower flowing upward to strip the ammonia. Ammonia-nitrogen
removals of up to 98 percent and down to concentrations of less
than 1 mg/1 have been achieved in experimental ammonia stripping
towers.
Technical Description
Because of the chemistry of ammonia, the pH of the waste water
from a biological treatment system should be adjusted to between
11 and 12 and the waste water is fed to a packed or cooling tower
type of stripping tower.*3 As pH is shifted to above 9, the
ammonia is present as a soluble gas in the waste water stream,
rather than as the ammonium ion. Ammonia-nitrogen removal of 90
percent has been achieved on a municipal effluent with
countercurrent air flows between 1.8 and 2,2 cubic meters per
liter (250 and 300 cubic feet per gallon) of waste water in an
experimental tower with hydraulic loadings between 100 and 125
liters per minute per square meter (2.5 and 3 gallons per minute
per square foot). The best performance was achieved with an air
rate of 5.9 cubic meters per liter (800 cubic feet per gallon)
and a hydraulic loading of 33 liters per minute per square meter
(0.8 gallons per minute per square foot); the ammonia
concentration was reduced to less than one part per million at
98-percent removal. The high percentage removal of ammonia-
nitrogen is achieved only at a substantial cost in terms of air
requirements and stripping tower cross-sectional area.24
Development Status
The ammonia stripping process (using both steam and air as the
stripping medium) has been practiced on "sour water" in the
petroleum refinery industry. The only significant difference
between the petroleum refinery application and that on poultry
processing waste would be the comparatively small size of
stripping tower required for poultry plants, compared to the
refinery. The air stripping of ammonia from biological effluent
is reported primarily on a pilot plant basis using various
equipment.51 Two large-scale installations of ammonia stripping
of lime-treated waste water are reported at South Tahoe,
California, and Windhoek, South Africa.15,24 The South Tahoe
ammonia stripper was rated at 14.2 M liters per day (3.75 MGD)
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and was essentially constructed as a cooling tower structure,
rather than a.s a cylindrical steel tower which might be used in
smaller sized plants.7*
Thus, although there is no reported use of ammonia stripping on
poultry processing plant waste, the technology is technically
well established and implementation, when limitations require it,
would be a possible alternative, particularly for well-stabilized
biological effluents.
Problems and Reliability
The reliability of this process has been found reasonable in
petroleum refinery applications of the process over many years.
Although the source of the ammonia may be different and there may
be other contaminants in the water stream, this should not affect
the established reliability of this process. The experience of
other users of the process will have identified potential
problems, and, presumably, the solutions for these problems can
be found. Among the maintenance requirements would be those
normally associated with the mechanical equipment involved in
pumping the waste water to the top of the tower where the feed is
introduced to the tower, and in maintaining the air blowers. The
tower fill would undoubtedly be designed for the kind of service
involved in treating a waste water stream that has some potential
for fouling. Problems with temperature and tower scaling are
also ; documented. Recent advances in possible anti-scale
chemicals appear promising,50 It has also been observed that
efficiency losses due to low temperature can be at least
partially overcome by breakpoint chlorination, by housing the
stripping tower, or heating the water or air with waste steam.
The most recent advance in the process includes an ammonia
recovery step and preliminary results indicate that most problems
with stripping towers have been overcome,74
Breakpoint Chlorination
When wastewater containing ammonia is treated with chlorine, a
chemical reaction toward the formation of chloramines is
observed. Further chlorination to the "breakpoint" (free
chlorine residuals predominate) converts the chloramines to
nitrogen gas which is lost to the atmosphere.
Technical Description
A detailed discussion of the chemistry of breakpoint chlorination
is readily found in numerous textbooks and references on
disinfection.*3,74 In summary, chlorine is added (as a gas or
liquid) to wastewaters containing ammonia in amounts sufficient
to cause the release of nitrogen gas. For each part of ammonia,
about nine parts of chlorine are required to drive the chemical
reactions from monochloramines through to nitrogen gas. At
proper chlorine feed rates, a contact time of 30 minutes or less
is necessary.
124
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Development Status
Breakpoint chlorination is a well-understood and well-documented
technology. Applications have centered on advanced treatment of
biological municipal wastes, although the concept has been found
to be useful as a "polishing" mode in conjunction with ammonia
stripping. It appears from the literature that the process
offers a viable alternative for ammonia control for ammonia
concentrations as are encountered in municipal biological
effluents.
Problems and Reliability
Under low pH (less than 6.0) conditions, chlorination of ammonia
may produce nitrogen trichloride which is highly odorous. The
removal of ammonia is not adversely affected if it becomes
necessary to add a base (sodium hydroxide) to overcome acid
conditions. Under field conditions described in the literature,
the natural alkalinity of the wastewater being treated proved to
be sufficient to preclude depression of pH below 6.0. The
process operates equally well in the temperature range of 5°C to
40°C; more chlorine may be needed at lower temperatures. Process
efficiencies consistently range between 95 and 99 percent and the
process is easily adapted to complete automation which helps
assure quality and operational control. Excessive use of
chlorine can result in substantial relative increases in
dissolved solids (choride salts) in effluents.
Spray/Flood Irrigation
A no discharge level for poultry processing waste water can be
and is being achieved by the use of spray or flood irrigation on
relatively flat land, surrounded by dikes to prevent runoff. A
cover crop of grass or other vegetation is maintained on the
land. Specific plant situations may preclude the installation of
irrigation systems; however, where they are feasible, the
economics can be very favorable and serious consideration should
be given to them.
Technical Description
Wastes are disposed of in spray or flood irrigation systems by
distribution through piping and spray nozzles over relatively
flat terrain or by the pumping and disposal through the ridge-
and-furrow irrigation systems which allow a certain level of
flooding on a given plot of land. Figure 18. Pretreatment for
removal of solids is advisable to prevent plugging of the spray
nozzles, or deposition in the furrows of the ridge-and-furrow
system, or collection of solids on the surface, which may cause
odor problems or clog the soil. Therefore, the BOD5 will usually
have already been reduced in preliminary treatment (primary plus
some degree of biological treatment) upstream from the
distribution system.
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Secondary
Treatment
Effluent
pH
Adjustment
Ammonia
Stripping
Tower
Treated
Effluent
Figure 17. Animonia Stripping
ro
Primary,
Secondary
or
rui nui -*
Tertiary
Treatment
Effluent
Molding
Basin
Pumping
System
N.
Application
Site
V
Grass or
Hay Crop
Figure 18. Spray/Flood Irrigation System
-------
In flood irrigation, the waste loading in the effluent would be
limited by the waste loading tolerance of tho particular crop
being grown on the land, or it may be limited by the soil
conditions or potential for vermin or odor problems.
Waste water distributed in either manner percolates through the
soil and the organic matter in the waste undergoes a biological
degradation. The liquid in the waste stream is either stored in
the soil or leached to a groundwater aquifer and discharged into
the groundwater. Approximately ten percent of the waste flow
will be lost by evapotranspiration (the loss caused by
evaporation to the atmosphere through the leaves of plants).29
Spray runoff irrigation is an alternative technique which has
been tested on the waste from a small meat packer33 and on
cannery waste.29 with this technique, about 50 percent of the
waste water applied to the soil is allowed to run off as a
discharge rather than no discharge, as discussed here. The
runoff or discharge from this type of irrigation system is of
higher quality than the waste water as applied, with BOD5 removal
of about 80 percent; total organic carbon and ammonia nitrogen
are about 85 percent reduced, and phosphorus is about 65 percent
reduced.
The following factors will affect the ability of a particular
land area to absorb waste water: 1) character of the soil, 2)
stratification of the soil profile, 3) depth to groundwater, 4)
initial moisture content, and 5) terrain and ground cover.29
The potentially greatest concern in the use of irrigation as a
disposal system is the total dissolved solids content and
particularly the salt content of the waste water. A maximum salt
content of 0.15 percent is suggested in the literature. Some
plants may require dilution upstream from the irrigation system
to reduce the dissolved solids and the salt content to acceptable
levels for continuing application of the waste water on land.
However, the average plant should have no problem with salt,
since the average salt content of poultry processing waste waters
is about a factor of fourteen less than the literature's
suggested limit of 0.15 percent.
An application rate of up to 330 liters per minute per hectare
(35 gallons per minute per acre) has been suggested in
determining the quantity of land required for various waste water
flows. This amounts to almost 5 cm (2 inches) of moisture per
day, and is relatively low in comparison with application rates
reported in the literature for various spray irrigation systems.
However, soils vary widely in their percolation properties and
experimental irrigation of a small area is recommended before a
complete system is built. In this report, land requirements were
based on 2.5 cm (1.0 inch) applied per operating day for six
months of the year with lagoon storage for six-months'
accumulation of waste water.
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If poultry processing plant waste waters were being used as the
sole nitrogen source for corn growth, the waste waters would
probably have to contain 250 to 500 mg/1 nitrogen. For lower
nitrogen concentrations, the corn crop would probably be damaged
by flooding or by heavy overWatering before the corn received
sufficient nitrogen from the waste waters. This is based on the
assumptions that one bushel of ccrn requires 454 gm (1 pound) of
nitrogen, that the yield is 120 bushels of corn per acre, and
that the corn would require from 25 to 75 cm (10 to 30 inches) of
water per season.3* This water rate amounts to 3.1 to 9.5 cm
(1.2 to 3.7 inches) of water per two weeks, over a four-month
season.
The economic benefit from spray irrigation is estimated on the
basis of raising two crops of grass or hay per season with a
yield of 13.4 metric tons of dry matter per hectare (six tons per
acre) and valued at $22 per metric ton ($20 per ton). These
figures are reportedly conservative in terms of the number of
crops and the price to be expected from a grass or hay crop. The
supply and demand sensitivity as well as transportation problems
for moving the crop to a consumer all militate against any more
optimistic estimate of economic benefits.35
Cold climate uses of spray irrigation may be subject to more
constraints and have greater land requirements than plants
operating in more temperate climates. However, a meat packer in
Illinois reportedly operated an irrigation system successfully.
Research indicates that wastes have been successfully disposed of
by spray irrigation from a number of other industries.29 Plants
located in cold climates or short growing areas should consider
two crops for spray irrigation. One could be a biological crop
such as corn and the other a grass crop. The grass crop could
tolerate heavier volume loadings without runoff and erosion, and
also would extend the irrigation season from early spring to
possibly late November. Corn, although a more valuable crop,
tolerates irrigation in cold climate areas only during the summer
months.
North Star found in its survey of the poultry, meat, and
rendering industries that the plants located in the arid regions
of the Southwest were most inclined to use spray or flood
irrigation systems.
Problems and Reliability
The long-term reliability of spray or flood irrigation systems is
a function of the ability of the soil to continue to accept the
waste, and thus reliability remains somewhat open to question.
Problems in maintenance are primarily in the control of the
dissolved solids level and salinity content of the waste water
stream and also in climatic limitations that may exist or
develop. Many soils may be improved by spray irrigation.
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Ion Exchange
Ion exchange, as a advanced waste treatment, is used as a
deionization process in which specific ionic species are removed
from the waste water stream. Figure 19, Ion exchange could be
used to remove salt (sodium chloride) or nutrients (ammonia) from
waste waters. Ion exchange resin systems have been developed to
remove specific ionic species, to achieve maximum regeneration
operating efficiency, and to achieve a desired effluent quality.
In the treatment of poultry processing waste, the desired
effluent quality would be a waste water with a salt concentration
of less than 300 mg/1. Ion exchange systems are available that
will remove up to 90 percent of the salt in a water stream.15
They can also be used to remove nitrogen.75
Technical Description
The deionization of water by means of ion exchange resin involves
the use of both cation and anion exchange resins in sequence or
in comhina
tion to remove an electrolyte such as salt.
RSO3H * NaCl RSO3Na + HC1
R-OH + HCL R-C1 + H2O
where R represents the resin.
The normal practice in deionization of water has been to make the
first pass through a strong acid column, cation exchange resins,
in which the first reaction shown in the equations occurs.
Effluent from the first column is passed to a second column of
anion exchange resin to remove the acid formed in the first step,
as indicated in the second reaction. As indicated in the two
reactions, the sodium chloride ions have been removed as ionic
species. A great variety of ion exchange resins have been
developed over the years for specific deionization objectives for
various water quality conditions.
Waste water treatment with ion exchange resins has been
investigated and attempted for over 40 years; however, recent
process developments in the treatment of biological effluent have
been particularly successful in achieving high-quality effluent
at reasonable capital and operating costs. One such process is a
modification of the Rohm and Hass, Desal process.15 In this
process a weak base ion exchange resin is converted to the
bicarbonate form and the biological effluent is treated by the
resin to remove the inorganic salts. After this step, the
process includes a flocculation/aeration and precipitation step
to remove organic matter; however, this should be unnecessary if
a sand filter or comparable system is used upstream of the ion
exchange system. The effluent from the first ion exchange column
is further treated by a weak cation resin to reduce the final
dissolved salt content to approximately 5 mg/1. The anion resin
in this process is regenerated with aqueous ammonia, and the
129
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u>
o
Partial
Tertiary
Treatment
Effluent
Backwash
Regenerant
System
Tertiary
Treated
Effluent
Figure 19. Ion Exchange
-------
cation resin with an aqueous sulfuric acid. The resins did not
appear to be susceptible for fouling by the organic constituents
of the biological effluent used in this experiment.
Other types of resins are available for ammonia, nitrate, or
phosphate removal as well as for color bodies, COD and fine
suspended matter.54 Removal of these various constituents can
range from 75 percent to 97 percent, depending on the
constituent.2 *
The cycle time on the ion exchange unit will be a function of the
time required to block or to take up the ion exchange sites
available in the resin contained in the system. Blockage occurs
when the resin is fouled by suspended matter and other
contaminants. The ion exchange system is ideally located at the
end of the waste water processing scheme, thus having the highest
quality effluent available as a feedwater.
To achieve a recyclable water quality, it may be assumed that
less than 500 mg/1 of total dissolved solids would have to be
achieved. Of the total dissolved solids, 300 mg/1 of salt are
assumed to be acceptable. To achieve this final effluent
quality, some portion or all of the waste water stream would be
subjected to ion exchange treatment.
The residual pollution will be that resulting from regeneration
of the ion exchange bed. The resin systems, as indicated
earlier, can be tailored to specific ion removal and efficient
use of regeneration chemicals, thus minimizing liquid wastes from
the regeneration step.
Development Status
Ion exchange as a unit operation is well established and commonly
used in a wide range of applications in water treatment and water
deionization. Water softening for boiler feed treatment and
domestic and commercial use is probably the most widespread use
of ion exchange in water treatment. Deionization of water by ion
exchange is used to remove carbon dioxide; metal salts such as
chlorides, sulfates, nitrates, and phosphates; silica; and
alkalinity. Specific resin applications such as in waste water
treatment have not been widespread up to the present time, since
there has not been a need for such a level of treatment-
However, processing development and experimental work have shown
the capability of ion exchange systems to achieve the water
quality that may be required for irrigation and closed-loop water
recycle systems.
Part of the economic success of an ion exchange system in
treating poultry processing plant waste will probably depend on a
high-quality effluent being available as a feed material. This
again, can be provided by an upstream treatment system such as
sand filtration to remove a maximum of the particularly
bothersome suspended organic material. However, the effect of a
low-quality feed would be primarily economical because of shorter
131
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cycle tiineii, rather than a reduction in the overall effectiveness
of the ion exchange system in removing a specific ionic species
such as salt.
Problems and Reliability
The application of the technology in waste treatment has not been
tested and therefore the reliability in that application has yet
to be established. The problems associated with ion exchange
operations would primarily center on the quality of the feed to
the ion exchange system and its effect on the cycle time. The
operation and control of the deionization-regeneration cycle can
be totally automated, which would seem to be the desired
approach. Regeneration solution is used periodically to restore
the ion exchange resin to its original State for continued use.
This solution must be disposed of following its use and that may
require special handling or treatment. The relatively small
quantity of regenerant solution will facilitate its proper
disposal by users of this system.
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SECTION VIII
COST, ENERGY, AND NONWATER QUALITY ASPECTS
SUMMARY
The waste water from poultry dressing and processing plants is
amenable to treatment in biological and advanced waste treatment
systems to achieve low levels of pollutants in the final
effluent. In-plant controls, byproduct recovery operations, and
strict water management practices can be highly effective in
reducing the waste load and waste water flow from any poultry
plant. Water management practices will reduce the requisite size
of biological and advanced treatment systems and improve their
waste reduction effectiveness.
For purposes of estimating waste treatment costs, the
subcategories of the poultry processing industry are divided into
groups based on size wherever the data indicated such a division
as appropriate. The plant size division is based on the number
of birds killed within each subcategory, except for plants that
further process only, which are grouped by output of finished
product. This division of the industry subcategories does not
imply the need to categorize according to size: the
categorization rationale does not support such a basis for
categorizing the industry. Total investment costs and unit
operating costs for waste treatment, on the other hand, will vary
with plant size. Costs that represent each subcategory situation
could not always be determined on the basis of one "typical"
plant size, given the wide range of production and waste water
flow within most of the subcategories. All costs are reported in
1973 dollars.
Waste water treatment investment cost is primarily a function of
waste water flow rate. Cost per unit of production for waste
treatment will vary with total investment cost and the production
rate. Therefore, the subcategory treatment costs have been
estimated on the basis of "typical" plants for each size. A
"typical" plant is a hypothetical plant with an average
production rate and with a waste water flow rate as indicated by
the data in Table 15. The average raw waste load for each
subcategory is reported in Sections IV and V of this report. The
raw waste load per unit LWK or FP does not vary with plant size
within each subcategory.
A capital investment will be required of most plants with
treatment systems to upgrade or install waste water treatment to
achieve the waste water quality specified for 1977 and 1983.
This additional investment required of a "typical" plant for each
size in a subcategory to meet the proposed limitations is
presented in Table 16. The capital costs will have to be
incurred both for the 1977 and the 1983 limitations, as indicated
in Table 16.
133
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Table 15. Typical Plant Operating Parameters Used for Estimating
Cost of Meeting Effluent Limitations
Plant Type
Chicken
Small
Medium
Large
Turkey
Fowl
Small
Large
Duck
Small
Large
Further Processing Only
Small
Large
Production
Birds/Day
51,000
95,000
207,000
12,000
26,400
65,000
3,000
12,000
kg (Ib) FP/Day
21,000 (47,000)
77,000 (170,000)
Waste Water Volume
MM liters/day
1.794
3.38
7.80
1.30
0.964
2.37
0.272
1.10
0.265
0.965
MGD
0.474
0.893
2.05
0.342
0.255
0.627
0.072
0.288
0.070
0.255
U)
JS
-------
u>
Table 16- Additional Investment Cost for "Typical" Plants in Each
Subcategory to Implement Each Indicated Level of
Treatment, No Previous Expenditure Included
!
Plant Type
Chicken
Small
Medium
Large
Turkey
Fowl
Small
Large
Duck
Small
Large
Further Processing Only
Small
Large
Total Industry Cost
•
1977
Limitations
$ 137,000
172,000
244,000
126,000
119,000
154,000
89,000
124,000
88,000
119,000
$13,874,000
1983
Limitations
$ 428,000
542,000
892,000
366,000
346,000
458,000
259,000
354,000
256,000
346,000
$38,642,000
- _---.„.. _^ • • - - - - - ••
New Source
Standards
$470,000
640,000
950,000
400,000
364,000
539,000
227,000
385,000
225,000
364,000
—
Irrigation
$183,000
323,000
687,000
138,000
105,000
235,000
35,000
118,000
34,000
105,000
—
-------
The estimated investment cost to achieve the 1977 limitations is
based on an analysis of the treatment systems in use in the
poultry process industry and their effectiveness on poultry plant
waste water. The costs for a "typical" plant to implement waste
treatment to achieve the 1977 limitations are based on the
following:
o Add an anaerobic lagoon or the equivalent, or expend the
same dollars on revisions of present treatment systems
by adding lagoon capacity, mechanical aeration, final
clarifier or similar option.
o install chlorination for the final effluent.
The following provide the basis for estimating the cost for the
"typical" plant to implement waste treatment to achieve the
proposed 1983 waste water limitations:
o 50 percent of the plants with waste treatment will have to
add dry offal handling systems.
o 50 percent of the plants will have to install improved
primary treatment such as dissolved air flotation.
o Install a microscreen or sand filter or equivalent, as a
advanced treatment.
o install a nitrification system or ammonia
stripping equipment or the equivalent, as a advanced
treatment.
The cost of the irrigation option is presented to demonstrate the
economic attraction of a waste treatment system that produces no
discharge. Irrigation by the small plant may be particularly
attractive from an economic viewpoint.
The cost for new point sources of waste water includes a basic
treatment system such as an anaerobic, aerated, aerobic lagoon
system plus dissolved air flotation. The costs are based on the
average waste water flow for each type of plant.
The total cost to the industry is estimated at $13.9 million for
the 1977 limitations and $38.6 million for 1983. These are cost
estimates that include the 50-percent factor based on the need of
only half of the plants with waste treatment to add a dry offal
handling system, and 50 percent to make significant improvements
in primary treatment facilities.
The investment in additional waste treatment facilities involves
the 26 percent of the industry with onsite treatment, less those
plants that already meet the limitations. The investment cost
per total number of birds killed per year varies from 0.5£ to 60
for 1977 and 1.70 to 180 for 1983 among the various plants in the
industry. This does not include the small-size duck processor
whose costs for treating feedlot wastes will probably greatly
136
-------
exceed the treatment costs for the duck processing plant waste
water. The plants that further process only will have a capital
investment per annual unit of production of 0.30/kg (0.750/lb)
for 1977 and l(*/kg (2.2«Vlb) to meet 1983 limitations.
The additions to plant operating cost and total annual cost for
plants to achieve the indicated level of treatment are listed in
total dollars and per unit of production in Tables 17 and 18.
The wide range in addition to unit costs is the result of the
small duck plant. It should also be noted that the unit annual
costs amount to between two and three times the unit operating
costs because of the high investment cost of the treatment
systems and the method of computing annual cost, using both 10-
percent depreciation and 10-percent cost of capital as add-ons.
Generally speaking, neither the capital requirements nor the
additions to the operating and total annual costs appear to
exceed the capabilities of plants in the industry to raise the
capital or to compete effectively and profitably and to earn a
satisfactory return, capital expenditures by the industry are
reported to have been about $60 million per year for 1970, 1971,
and 1972.3* Waste treatment will require a higher share of these
expenditures as the limitations are implemented.
The total energy consumption in waste water treatment by the
poultry processing industry is of little consequence in
comparison to the present total power consumption of gas and
electricity. The waste treatment power consumption to achieve
1983 limitations amounts to 2.2 percent of the total consumption
of fuel and electricity by poultry plants. Waste treatment power
consumption amounts to about 12 percent of the electrical power
consumption in poultry plants.
With the implementation of the proposed limitations, land becomes
the primary waste sink instead of air and water. The waste to be
landfilled can improve soils with nutrients and soil conditions
contained in the waste. Odor problems can be avoided or
eliminated in all treatment systems.
"TYPICAL" PLAN*!
The waste treatment systems applicable to waste water from the
poultry processing industry can be used by all plants in the
subcategories of the industry. A hypothetical "typical" plant
was constructed for each size in each subcategory as the basis
for estimating investment cost and total annual cost for the
application of each waste treatment system. The costs were
estimated and, in addition, effluent reduction, energy
requirements, and nonwater quality aspects of the treatment
systems were determined.
The waste treatment systems are applied on the basis of the plant
constructs for each subcategory, as indicated previously in Table
15.
137
-------
Table 17. Addition to the Total Annual Cost and Operating* Cost for a Plant
in Each Subcategory to Operate Treatment System as Described
Plant Type
Chicken
Small
Medium
Large
Turkey
Fowl
Small
Large
Duck
Small
Large
Further Processing
Only
Small
Large
1977
Operating
$22,450
26,800
35,200
20,700
19,800
24,600
16,450
20,000
16,400
19,800
Annual
?49,850
61,200
84,000
45,900
43,600
55,400
34,250
44,800
34,000
43,600
1983
Operating
$ 70,650
95,100
161,400
60,900
56,000
79,300
41,860
111,460
41,550
55,900
Annual
$183,650
237,900
388,600
159,300
149,000
201,700
57,600
153,200
110,350
148,900
New Source
Operating
$54,000
67,100
90,400
48,300
45,400
59,700
35,300
46,400
35,100
45,400
Annual
?148,000
195,100
280,400
128,300
118,200
167,500
80,700
123,400
80,100
118,200
Irrigation
Operating
$29,800
35,000
46,000
27,700
26,250
32,000
22,900
26,600
22,900
26,200
Annual
$66,400
99,600
183,400
55,300
47,250
79,000
29,900
50,200
29,700
47,200
CO
*Total annual cost includes operating cost plus capital cost and depreciation in dollars per
Total operating cost includes manpower and burden, supplies, chemicals, power, taxes, and
insurance in dollars per year.
year,
-------
Table 18. Additions to the Annual Cost and Operating Cost Per Unit of Production for
a Plant in Each Subcategory to Operate Treatment System as Described
Plant Type
Chicken, C/bird
Small
Medium
Large
Turkey, /bird
Fowl, p/bird
Small
Large
Duck, C/bird
Small
Large
Further Processing
Only
Small, 0/kg
(C/lb)
Laree, c/kg
(C/lb)
1977
Operating
0.18
0.11
0.07
1.0
0.3
0.15
3.2
1.0
0.31
(0.14)
0.10
1t0.05)
Annual
0.39
0.26
0.16
2.25
0.66
0.34
6.7
2.2
0.64
(0.29)
0.23
(0.10)
1983
Operating
0.55
0.4
0.3
3.0
0.85
0.49
8.2
2.8
0.78
(0.35)
0.29
(0.13)
Annual
1.44
1.0
0.75
7.8
2.26
1.24
21.8
7.5
2.10
(0.94)
0.77
(0.35)
New Source
Operating
0.42
0.28
0.18
2.4
0.69
0.37
6.9
2.3
0.65
(0.30)
0.24
(0.11)
Annual
1.16
0.82
0.54
6.3
1.8
1.03
15.8
6.0
1.50
(0.68)
0.61
(0.28)
Irrigation
Operating
0.23
0.15
0.09
1.36
0.40
0.20
4.5
1.3
0.43
(0.20)
0.14
(0.06)
Annual
0.52
0.42
0.35
2.7
0.72
0.49
5.9
2.5
0.56
(0.25)
0. 24
(0.11)
-------
WASTE TREATMENT SYSTEMS
The waste treatment systems included in this report as
appropriate for use on poultry processing plant waste water
streams can be used, subject to specific operation constraints or
limitations as described later, by most plants in the industry.
The use of some treatment systems may be precluded from
consideration by technical, physical, or economic impracticality
for some plants.
The waste treatment systems, their uses, and typical range of
effluent reduction associated with each are listed in Table 19.
The dissolved air flotation system can be used upstream of any
biological treatment system. The use of chemicals will increase
the quantity of grease removed from the waste water system, as
indicated in Table 19.
The biological treatment systems are generally land intensive
because of the long retention time required in natural biological
processes. Mechanically assisted systems have reduced the land
requirements, but increased the energy consumption and cost of
equipment to achieve comparable levels of waste reduction. Some
of the advanced systems are interchangeable. They can be used at
the end of any of the biological treatment systems, as required,
to achieve a specific effluent quality. Chlorination is included
as a disinfection treatment.
The most feasible system for poultry processors to achieve no
discharge at this time is flood or spray irrigation. Closing the
loop to a total water recycle or reuse system may be technically
feasible, but far too costly for consideration. The irrigation
option does require large plots of accessible land—roughly 2.0
hectares/million liters (18 acres/thousand gallons) of waste
water per day—and limited concentrations of dissolved solids.
More detailed descriptions of each treatment system and its
effectiveness are presented in Section VII—Control and Treatment
Technology.
A study conducted by the Economic Research Service of the USDA
reported the type of waste water treatment employed by 386
poultry plants.1 The distribution between private onsite
treatment and municipal treatment reported in this USDA study
provided the basis for the data presented in Table 20 on industry
waste water treatment practice by subcategory and plant size.
The distribution among subcategories and sizes is based on North
Star survey questionnaire data covering about 140 plants. The
total number of 390 plants is based on an average of the number
reported in three different sources and on information collected
from the industry during this research program.1,2,36
There is a dominant waste treatment pattern among duck processors
who almost always treat their own waste water; except for one
plant, duck processing plants apparently include a duck feedlot
140
-------
Table 19. Waste Treatment Systems, Their Use and Effectiveness
Treatment System
Dissolved air
flotation (DAF)
DAF with pH control
and flocculants
added
Anaerobic + aerobic
lagoons
Anaerobic contact
process
Activated sludge
Extended aeration
Anaerobic lagoons +
rotating biological
contactor
Chlorination
Sand filter
Microstrainer
Ammonia stripping
Chemical
precipitation
Spray irrigation
Flood irrigation
Ponding and
evaporation
Nitrification and
denitrification
Use
Effluent Reduction
Primary treatment or
by-product recovery
Primary treatment or
by-product recovery
Secondary treatment
Secondary treatment
Secondary treatment
Secondary treatment
Secondary treatment
Finished and
disinfection
Tertiary treatment &
secondary treatment
Tertiary treatment
Tertiary treatment
Tertiary treatment
No discharge
No discharge
No discharge
Tertiary treatment
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
BOD5, 95% removal
BOD5, 90-95% remova]
BOD5, 90-95% removal
, 95% removal
, 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
90-95% removal
Phosphorus, 85-95%
removal, to 0.5 mg/1
or less
Total
Total
Total
N, 85% removal
141
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Table 20. Industry Breakdown by Subcategory, Size, and Type of Waste Treatment
Plant Type
Chickens
Small
Medium
Large
Turkey
Fowl
Small
Large
Ducks
Small
Large
Further Processing
Only
Small
Large
Total
Total
Number
of
Plants
222
133
82
7
112
26
18
8
10
4
6
20
16
4
390
Private, On-Site
Treatment
Number
of Plants
64
39
23
2
22
5
3
2
9
4
5
2
2
0
102
Percent of
Subcategory
29
20
19
91
10
26.2
Municipal
Treatment
Number
of Plants
153
91
57
5
89
20
14
6
1
0
1
18
14
281
Percent of
Subcategory
69
79
76
9
90
72-. 0
No
Treatment
Number
of Plants
5
3
2
C
1
1
1
0
0
0
7
Percent of
Subcategory
2
1
5
0
0
1.8
-------
and its waste water. Likewise, a poultry plant that further
processes only is almost always on municipal treatment. In fact.
North Star found no further processing only plant with an onsite
treatment system. Among the subcategories other than ducks and
further processing only, between 20 and 30 percent of the plants
apparently have onsite treatment. The number of plants indicated
in Table 20 with no treatment and a waste water discharge to a
stream is based on the data in the USDA study previously
mentioned.
Irrigation of waste water was reported by one plant located in an
arid region of the Western United States and by another in the
East North Central region of the country. A microstrainer was
observed in use as a final treatment device in one plant. It was
found to be very effective in the removal of suspended solids.
Seventeen plants reported using dissolved air flotation as a
primary treatment. Chlorination was reportedly used as a
finishing treatment by 14 plants among the respondents to the
survey questionnaire.
TREATMENT AND CONTROL COSTS
In-Plant Control Costs
The cost of installation of in-plant controls is primarily a
function of the specific plant situations. Building layout and
construction design will largely dictate what can be done, how,
and at what cost in regard to in-plant waste control techniques,
The in-plant control costs included in the investment cost
estimates are for water recirculation to the feather flow-away
system for 1977 and dry offal handling and improved primary
treatment for 1983.
Investment Costs Assumptions
The waste treatment system costs are based on the plant
production, waste water flow and BODS figures listed previously
for "typical," but hypothetical, plants in each subcategory.
Investment costs for specific waste treatment systems are largely
dependent on the waste water flow or hydraulic load. Most of the
lagoon systems are designed on BOD5 loading, which has been shown
to increase with increased water use, however, cost estimates
based on flow are adequate for the purposes of this study.
Cost effectiveness data are presented in Figures 20 and 21, as
the investment cost required to achieve the indicated BOD5
removal with two different waste treatment systems at two levels
of waste water flow. The low flow (Figure 20) is typical for the
average size plants in the industry. The high flow (Figure 21)
is more typical of the large plants in the industry. The raw
waste reduction is based on the construct of idealized waste
treatment systems with the incremental waste reduction achieved
by adding treatment components to the system as indicated in
143
-------
p
z
UJ
O
cc
UJ
CTION
Q
UJ
CC
Q
O
UJ
CO
5
g
3
QC
UJ
H
5
X
o
QC
Q.
99.9
99.5
99
98
95
90
80
70
60
50
40
30
20
10
-
---j_ g TmTlflRY TnrATMFMT
*
.
-
-
-
• LAGOON 1
TREATMENT U-
- SYSTEM 1
-
_
-
-
-
"
I 1 ADVANCED SECONDARY
f (TREATMENT
1 ^ [ SECONDARY TREATMENT
| [LEVEL
1
1
1
ACTIVATED SLUDGE
| SYSTEMS
1
1
•— -rmiviMriT incMimci^i LEVEL.
i i i i i i i i i
100 200 300 400 500 600 700 800 900 1000
INVESTMENT COST ($1000's)
Figure 20. Waste Treatment Cost Effectiveness at Flow
of 1.14 Million Liters/Day (0.300 MGPD)
-------
APPROXIMATE RAW WASTE LOAD REDUCTION (PERCENT)
•-'••- '• . •.:,•-•,< (o vi oo to co to to J° 5°
D O O OOOOOO O OV 00 CO O1 CO
L
1
s
k
.-• - I',.-
AGOON
•REATMENT
YSTEM
.*"
-,_-*J TERTIARY
("TREATMENT
i
J JADVANCED SECONDARY
i - *• ITREATMENT
| ISECONDARY TREATMENT
1 * 1LEVEL
ACTIVATED
SLUDGE &
AERATION
SYSTEMS
PRIMARY TREATMENT
LEVEL
1 J« ,A ,A.,,. J. 1 —I ^J 1 1 -*-
INVESTMENT COST ($1000's)
Figure 21. Waste Treatment Cost Effectiveness at Flow
of 3 Million Liters/Day (0.800 MGPD)
-------
-------
Table 21. Waste Treatment System Configurations
for Cost Effectiveness Curves
Low Cost System
Catch basin
+ Dissolved air
flotation
+ Anaerobic and
aerobic lagoons
+ Aerated lagoon
+ Sand filter
High Cost System
Catch basin
+ Dissolved air
flotation
+ Activated sludge
+ Extended aeration
+ Sand filter
Total Raw
Wast e-- Reduet ion:-
BOD5 (%)
0
30
95
98
99+
-------
for new ventures. The ten percent figure is probably
conservative and thus tends to contribute to a high estimate of
total annual cost, operating cost includes all the components of
total annual cost except capital cost and depreciation, wherever
it is reported.
The depreciation component of annual cost was estimated on a
straight-line basis, with no salvage value and a ten-year life
for all investment costs, except land cost which was not
depreciated.
The operating and maintenance costs for the 1983 systems include
the cost of one man-year at $4.20 per hour plus 50 percent for
burden, supervision, etc. A licensed waste treatment operator
would add another $5,000 to operating costs per year. One-half
man-year was used for the annual cost for the 1977 limitations
plus the 50-percent burden, etc. General and maintenance
supplies, taxes, insurance, and miscellaneous operating costs
were estimated at five percent of the total investment cost per
year. Specific chemical-use costs were added when such materials
were consumed in the waste treatment system. By-product income,
relative to waste treatment, was credited only in the irrigation
system for 13,400 kg (29,480 lb)of dry matter (hay or grass) per
hectare, at $22 per 100 kg of hay, with two crops per year. This
is equivalent to a yield of six tons per acre valued at $20 per
ton of dry hay.
Costs per unit of production were based on 250 operating days per
year at the average daily production rate for plants in the
chicken, fowl, and further processing only subcategories. Turkey
and duck processors were assumed to slaughter only 170 days, or
about 2/3 of the year, and at the average daily production for
each subcategory.
ENERGY REQUIREMENTS
The electrical energy consumption by the poultry processing
industry was reported for 1971 at 1.2 million KWH and total heat
and power consumption at 6.4 million KWH.e The poultry
processing industry consumes relatively small quantities of
electrical energy, but large quantities of fuel for cooking and
heating. The waste treatment systems require power primarily for
pumping and aeration. The aeration horsepower is a function of
the waste load, and that for pumping depends on waste water flow
rate.
Total power consumption for current waste treatment, which will
be essentially the same for 1977 limitations, is estimated to be
about 50 million KWH per year for the poultry processing
industry. This amounts to about 4.2 percent of the industry's
electrical energy consumption and less than 1.0 percent of total
energy consumption reported for 1971. An additional power
consumption increment of 50 to 60 million KWH is estimated to be
required to achieve 1983 limitations. Again, using the 1971
148
-------
consumption levels as a baseline, this amounts to 8.5 percent of
electrical energy and 2.2 percent of total energy. This nominal
increase does not appear to raise serious power supply or cost
questions for the industry. However, the widespread use of
chlorine as a disinfectant may pose some energy problems in the
future, or, conversely, the future supply of chlorine may be
seriously affected by the developing energy situation in which
event alternative disinfection procedures may be required.
Waste treatment systems impose no significant addition to the
thermal energy requirements of plants. Waste water can be reused
in various services in poultry processing plants. Heated waste
waters improve the effectiveness of anaerobic ponds, which are
best maintained at 32°C (90°F) or higher. Improved water use and
thermal efficiencies are possible within a plant when waste water
reuse is maximized.
Waste water treatment costs and effectiveness can be improved by
the use of energy and power conservation practices and techniques
in the processing plant. The waste load tends to increase with
increased water use. Reduced water use therefore reduces the
waste load, pumping costs, and heating costs, the last of which
can be further reduced by Water reuse, as suggested previously.
NONWATER POLLUTION BY WASTE TREATMENT SYSTEMS
Solid Wastes
Solid wastes are the most significant nonwater pollutants
associated with the waste treatment systems applicable to the
poultry processing industry. Screening devices of various design
and operating principles are used primarily for removal of large
solids from waste water. These solids may have some economic
value as inedible rendering material, or they may be landfilled
or spread with other solid wastes.
The solids materials separated from the waste water stream which
contain organic and inorganic matter, and the chemicals added to
aid solids separation are called sludge. Typically, sludge
contains 95 - to 98-percent water before dewatering or drying.
Both primary and biological treatment systems generate some
quantity of sludge; the quantity will vary by the type of system
and is roughly estimated in Table 22.
149
-------
Ui
o
Table 22. Sludge Volume Generation
by Waste Treatment Systems
Treatment System
Dissolved air flotation
Anaerobic lagoon
Aerobic and aerated lagoons
Activated sludge
Extended aeration
Anaerobic contact process
Rotating biological contactor
Sludge Volume as Percent of Raw
Waste Water Volume
Up to 10%
Sludge accumulation in these
lagoons is usually not sufficient
to require removal at any time.
10 to 15%
5 to 10%
Approximately 2%
Unknown
-------
The raw sludge can be concentrated, digested, dewatered, dried,
incinerated, landfilled on site, or spread in sludge holding
ponds. The sludge from any of the treatment systems, except air
flotation with polyelectrolyte chemicals added, is amenable to
any of these sludge handling processes.
The sludge from air flotation with chemicals addition has been
found to be difficult to dewater, A dewatered sludge is an
acceptable landfill material. Sludge from biological treatment
systems is normally ponded by industry plants on their own land
or dewatered or digested sufficiently for hauling and deposition
in public landfills. The final dried sludge material can be
safely used as an effective soil builder. Prevention of runoff
is a critical factor in plant-site sludge holding ponds. Costs
of typical sludge handling techniques for each biological
treatment system generating sufficient quantities of sludge to
require handling equipment are included in the costs for these
treatment systems.
For those waste materials considered to be non-hazardous where
land disposal is the choice for disposal, practices similar to
proper sanitary landfill technology may be followed. The
principles set forth in the EPA1 s Land Disposal of Solid Wastes
Guidelines (CFR Title 40, Chapter 1; Part 2U1) may be used as
guidance for acceptable land disposal techniques.
For those waste materials considered to be hazardous, disposal
will require special precautions. In order to insure long-term
protection of public health and the environment, special
preparation and pretreatment may be required prior to disposal.
If land disposal is to be practiced, these sites must not allow
movement of pollutants such as fluoride and radium-226 to either
ground or surface water. Sites should be selected that have
natural soil and geological conditions to prevent such
contamination or, if such conditions do not exist, artificial
means (e.g., liners) must be provided to insure long-term
protection of the environment from hazardous materials. Where
appropriate, the location of solid hazardous materials disposal
sites should be permanently recorded in the appropriate office of
the legal jurisdiction in which the site is located.
Air Pollution
Odors are the only significant air pollution problem associated
with waste treatment in the poultry processing industry.
Malodorous conditions usually occur in anaerobic waste treatment
processes ,or localized anaerobic environments within aerobic
systems. However, it is generally agreed that anaerobic ponds
will not create serious odor problems unless the p ocess water
has a sulfate content; then they most assuredly wil?.
j
Sulfate waters are definitely a localized condition, varying even
from well to well within a specific plant. In northern climates,
the change in weather in the spring may be accompanied by a
period of noticeable odors. In some cases, a cover or collector
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of the off-gas from the pond is an effective odor control device.
The off-qas is burned in a flare.
Odors have been generated by some air flotation systems which are
sometimes housed in a building, thus localizing, but intensifying
the problem. Minimizing the unnecessary holdup of any skimmings
or grease-containing solids has been suggested as a remedy.
Odors can best be controlled by elimination at the source, rather
than resorting to treatment for odor control, which remains
largely unproven at this time.
Noise
The only material increase in noise within a processing plant
caused by waste treatment is that caused by the installation of
an air flotation system or aerated lagoons with air blowers.
Large pumps and an air compressor are part of an air flotation
system. When such a system is housed in a low-cost building, the
noise generated by an air flotation system is confined within the
building, but the noise may be amplified to high levels in the
building by such installation practices. All air compressors,
air blowers, and large pumps in use on intensively aerated
treatment systems, and other treatment systems as well, may
produce noise levels in excess of the Occupational Safety and
Health Administration limitations. The industry must consider
these limitations in solving its waste problems.
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SECTION IX
EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION OF
THE BEST PRACTICABLE CONTROL TECHNOLOGY
CURRENTLY AVAILABLE—EFFLUENT LIMITATIONS GUIDELINES
INTRODUCTION
The Agency/ in establishing effluent limitations which must be
achieved by July 1, 1977, is to specify the degree of effluent
reduction attainable through the application of the Best
Practicable Control Technology Currently Available. This
technology is generally based upon the average of the best
existing performance by plants of various sizes, ages, and unit
processes within the industrial category and/or subcategory.
This average was not based upon a broad range of plants within
the poultry processing industry, but based upon performance
levels achieved by exemplary plants.
Consideration was also given to:
o The total cost of application of technology in relation to
the effluent reduction benefits to be achieved from such
application;
o The size and age of equipment and facilities involved;
o The processes employed;
o The engineering aspects of the application of various types
of control techniques;
o Process changes;
o Nonwater quality environmental impact (including energy
requirements) .
While Best Practicable Control Technology Currently Available
emphasizes treatment facilities at the end of a manufacturing
process, it includes waste water control measures within the
process itself which are considered to be normal practice within
an industry.
A further consideration is the degree of economic and engineering
reliability which must be established for the technology to be
"currently available," As a result of demonstration projects,
pilot plants, and general use, there must exist a h:jh degree of
confidence in the engineering and economic practic bility of the
technology at the time of start of construction of the control
facilities.
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EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION OF
BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY AVAILABLE
Based on the information contained in Sections III through VIII
of this report, a determination has been made that the quality of
effluent attainable through the application of the Best
Practicable Control Technology Currently Available is as listed
in Table 23, In the industry study summarized herein, ten of the
plants in the chicken category, two plants in the turkey
category, and one plant in the duck processing category meet the
proposed BOD5 limitations. All plants in the sample representing
the fowl and further processing only subcategories were found to
discharge to municipal treatment systems. Therefore, no final
effluent data were available in these subcategories.
Plants with onsite rendering or further processing (not including
cut-up only operations), in addition to slaughtering, require
adjustments in the BOD5, TSS, and Grease limitations. An
adjustment in effluent limitations is also warranted for duck
processing plants that have an adjunct feedlot operation. The
adjustments for further processing are the values for further
processing only given in Table 23; the adjustments for onsite
rendering are the values developed for the independent rendering
industry.39 These adjustment factors are presented in Table 24,
Adjustments for further processing are permitted only for the
production from further processing that includes cooking and
processing activity encompassed as part of cooking such as
breading, spicing, canning, etc. This excludes cut-up only
operations. The reason for this is that the raw waste loads for
plants with only slaughtering operations are not distinctively
different from plants with slaughter plus cut-up operations (see
Section IV) .
It appears that the circumstances of several duck processors
associated with feedlots are somewhat different than processors
operating alone. As a result, it is apparent that any effluent
restrictions should be so derived as to properly account for
waste load contributions from both the feedlot and the processor.
While the small number of operations affected does not appear to
warrant a specific separate regulation or new subcategory , the
Agency has concluded that the effluent limitation for a combined
feedlot/processor should be developed on an additive basis.
Thus, in the event that waste streams from the feedlot and
processor are combined for treatment or discharge, the quantity
of each pollutant or pollutant property controlled for each
separate component or waste source shall not exceed the specified
limitation for that waste source. For parameters regulated by
only one of the potentially applicable regulations, the ultimate
limitation should be derived on a flow-proportioned basis. For
example, the pollutant "total suspended solids" is not controlled
by an effluent limit for a duck feedlot, but is specified for a
duck processor. In this instance, the portion (determined by
respective flow volume) of suspended solids attributable to the
processor in the combined effluent must not exceed the limitation
specified for a duck processor in Table 23,
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Table 23. Recommended Effluent Limitations for July 1, 1977
Industry
Subcategory
Chickens
Turkeys
Fowl
Ducks
Further Processing
Only
Effluent Parameters
B0%,_. kg/kkg LWK*
0.46
0.39
0.61
0.77
0.30 kg/kkg FP
SS, kg/kkg LWK '
0.62
0.57
0.72
0.90
0.35 kg/kkg FP
Grease, kg/kkg LWK
0.20
0.14
0.15
0.26
0.10 kg/kkg FP
Fecal Coliform,
Max. Count/100 ml
.
400
400
400
400
400
Ln
Ui
*kg/kkg LWK is equivalent to lb/1000 Ib LWK
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plants as well. The further processing adjustment factors become
significant when a plant further processes the majority of its
kill,
IDENTIFICATION OF BEST PRACTICABLE CONTROL
TECHNOLOGY CURRENTLY..AVAILABLE
Best Practicable Control Technology Currently Available for the
poultry processing industry involves biological waste treatment
following in-plant primary treatment for grease and solids
recovery. By definition, in-plant byproduct recovery of blood,
feathers, and offal is not considered as in-plant primary
treatment. To assure that the biological treatment system will
successfully achieve the limits specified, plant operators should
consider reduction of the raw waste load entering the treatment
system by employing one or more of the following housekeeping and
management measures, all of which are currently practiced at some
plants in the industry:
o Appoint a person with specific responsibility for water
management. This person should have reasonable powers to
enforce improvements in water and waste management,
o Determine or estimate water use and waste load strength from
principal sources. Install and monitor flowmeters in all
major water use areas,
o Control and minimize flow of freshwater at major outlets
by installing properly sized spray nozzles and by regulating
pressure on supply lines,
o Shut off all unnecessary water flow during work breaks.
o In-plant primary systems—catch basins, skimming tanks, air
flotation, etc.—should provide for at least a 30-minute
detention time of the waste water.
o Avoid overfilling cookers in rendering operation.
o Provide and maintain traps in the cooking vapor lines of
rendering operations to prevent overflow to the condensers.
This is particularly important when the cookers are used to
hydrolyze feathers,
o Provide frequent and regularly scheduled maintenance attention
for byproduct screening and handling systems throughout the
operating day.
o Dry clean all floors and tables prior to washdown to reduce
the waste load. This is particularly important in the
bleeding, cutting, and further processing areas and all
other areas where materials tend to be spilled.
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o Use high-pressure, low-volume spray nozzles or steam augmented
systems for plant washdown.
o Control inventories of raw materials used in further processing
so that none of these materials are wasted to the sewer.
Spent raw materials should be routed to rendering.
o Make all employees aware of good water management practices
and encourage them to apply these practices.
The above practices can readily help in waste control by reducing
raw waste loads. Other actions such as minimizing the amount of
chemicals and detergents used, keeping at USDA-approved water use
rates in scalders and chillers, installing "demand" valves on all
freshwater outlets, or practicing dry offal handling are other
potentially useful waste control options which need not
necessarily be instituted. Available information indicates that
a number of plants are practicing the principles encompassed in
the above waste control activities. Even if these control
activities are not fully implemented, well-operated treatment
processes currently used by the industry and listed below will
permit the recommended limits to be achieved.
1. Anaerobic lagoon + aerobic {shallow) lagoons;
2. Activated sludge (or extended aeration) + aerobic (shallow)
lagoons;
3, Aerated lagoons + aerobic (shallow) lagoons;
U. Anaerobic + aerated + aerobic (shallow) lagoons.
Plants with higher-than-average raw waste loads or undersized
treatment systems may require an additional solids removal stage
(e.g., clarifier). Chlorination usually will be required as the
final treatment process.
RATIONALE FOR THE SELECTION OF BEST PRACTICABLE
CONTROL TECHNOLOGY CURRENTLY AVAILABLE
The rationale used in developing the effluent limitations
presented in Table 23 was based upon actual performance data of
plants having complete biological waste treatment or upon raw
waste characteristics and transfer of waste treatment technology.
A complete biological treatment system would include any properly
sized system mentioned in the preceding subsection.
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SIgS, AGE, PROCESSES EMPLOYED,
LOCATION OF FACILITIES
The processes employed in small and large poultry slaughtering
plants and further processing plants are basically similar.
Furthermore, the factors of size, age, and processes employed did
not appear to affect the pollution control techniques used.
Hence these factors were not directly employed in establishing
effluent limitations. Also, the location of facilities was not a
major factor, although it may contribute slightly to seasonal
variations in waste load and final effluent.
TOTAL COST OF APPLICATION IN RELATION TO
EFFLUENT REDUCTION BENEFITS
Based on information contained in Section VIII of this report,
the total investment cost to the poultry industry to implement
the waste treatment to achieve the 1977 effluent limitations is
estimated to be $13.9 million. This amounts to 23 percent of
total capital expenditures of $60 million by the industry in each
of the three years 1970, 1971, and 1972.
Moreover, this level of expenditure is associated with a
substantial reduction in pollution discharged directly to
navigable waters. Using BOD5 as a basis for calculations, it is
estimated that the poultry processors (with a direct stream
discharge) are discharging about 13 million pounds of BODJ5 to
streams each year at present levels of pollution control. Full
implementation of the effluent limitations for BOD5 by these
plants is estimated to provide a reduction of 75 percent in BOD5.,
to a level of about 3.5 million pounds per year. The investment
cost versus pollution load reduction relationship amounts to
about $1.50 per pound of BOD5 removed for the time period during
which the 1977 limitations are applicable.
The additional operating cost associated with achieving 1977
limitations for chicken, turkey, and fowl processors varies from
0.072/bird to l*/bird, and for duck processors from 1.0*/bird to
3.22/bird. Plants that further process only will incur
additional operating costs from 0.1* to 0.3*/kg FP (0.05 to
0.14£/lb FP). The total annual cost increase per unit of
production to achieve 1977 limitations varies from 2.2 to 2.4
times the operating cost increase. The large plants in the
industry will experience the lower cost increase per unit of
production.
DATA PRESENTATION
Table 25 presents the data for 13 exemplary chicken processing
plants. Included in Table 25 are the plant size (thousands of
birds per day); effluent flow; raw and final waste loads for
BOD5, TSS, and grease; fecal coliform counts in the final treated
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Table 25. Waste Treatment Data For Exemplary
Chicken, Turkey, and Duck Plants
Plant
Number
Chickens
1
2
3
4
5tt
6
7
8
9
10
11
12
Turkeys
13
14
15
16
17
Ducks
18
19
Flow
liters/bird
(gal/bird)
29.1 (7.7)
24.2 (6.4)
30.3 (8.0)
37.8 (10.0)
51.5 (13.6)
40.9 (10.8)
23.5 (6.2)
23.8 (6.3)
15.5 (4.1)
33.3 <8.8)
17.4 (4.6)
35.6 (9.4)
113.9 (30.1)
61.3 (16..2)
170.3 (45)
135.1 (35.7)
132.5 (35)
71.5 (18.9)
78.3 (20.7)
Production
1000 birds/day
65
55
36
65
70
140
45
84
22
BOD5,
kg/kkg LWK*
Raw
7.12
6.98
5.88
—
10.54
13.00
6.30
4.32
6.29
200 13.48
60
85
9.4
21-
4.4.6
4.36
Final
0.47
0.39
0.66
0.26
0.24
0.51
0.50
0.39
0.45
0.64
0.40
0.32
;
4.69! 1-25
2.70 0.18
6 ! 3.22 0.59
4.2
20
0.96 0.49
0.41
i
10 j 7.52 0.54
15 6.59 1.32
ss,
kg/kkg LWK*
Raw
6.06
5.00
5.77
—
5.01
5.11
10.30
2.38
5.32
5.47
3.97
3.51
3.55
1.52
2.41
0.99
—
3.47
5.24
Final
0.14
0.44
0.23
0.52
0.19
0.12
1.40
0.43
0.59
0.46
0.50
0.22
0.62
0.57
1.18
0.50
0.63
0.81
1.61
Grease,
kg/kkg LWK*
Raw
—
5.39
1.67
—
4.03
2.91
6.10
—
—
—
—
—
1.46
0.44
0.88
0.35
—
3.05
0.66
Final
—
0.45
0.19
—
0.34
0.14
0.20
—
—
—
—
—
0.025
0.13
0.067
0.076
—
0.13
0.073
Final Fecal
Coliforms**,
Counts/100 ml Waste Treatment System
1100
—
—
<100(CL)
<100(CL)
3300(CL)
~
—
<100
—
—
—
anaerobic, 3 aerobic
2 aerated, 2 aerobict
2 anaerobic, aerobic
3 anaerobic, aerated,
aerobic
activated sludge,
micro strainert
anaerobic , aerated ,
aerobic
aerated
extended aeration, aero.b-.ict
aerated, 2 aerobic
3 aerated, 2 aerobict
anaerobic , aerated , aerobict
extended aeration, aerobic
100 activated sludge, aerobic
3 aerated
<100(CL) aerated, 2 aerobict
1700 anaerobic, aerobic
aerated , aerobic
<100(CL) activated sludge, aerobic
<100(CL) 3 aerated, 2 aerobic
*kg/kkg LWK. = lb/1000 Ib LWK.
**(CL) indicates chlorliration of-final effluen.t.
tindicates air flotation primary treatment.
!tThe performance of the treatment system for Plant 5
was used to establish 1983 effluent limitations.
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effluent; and the type of biological waste treatment systems
used.
Table 25 also includes the same information tor exemplary turkey
and duck processing plants. Similar data for fowl processing and
for further processing only plants are not available because all
of these plants that responded to the questionnaire indicated
discharged their raw waste water to municipal treatment systems.
Chickens
Data for three of the chicken processing plants represent
information obtained from our field sampling survey; data for two
plants were provided directly by the companies; and data for
eight plants were obtained from questionnaire information.
The BOD5 effluent limitation of 0.46 kg/kkg LWK is the average of
all final BOD5 values except for Plant No. 5 presented under
chickens in ~*Table 25. The value for Plant No. 5 was excluded
because its waste treatment system includes advanced waste
treatment. Seven of the twelve plants listed in Table 25 meet
this effluent limitation; eight of thirty-two plants for which
final data were available meet the limitation. Using the average
of all flow values (excluding Plant No. 5) of 28.3 liters (7.5
gal)/birdr and an average bird weight of 1.74 kg (3.8 Ib) , the
corresponding final BOD5 effluent concentration is 28 mg/1. This
concentration is considered to be attainable using the best
practicable control technology currently available.
The suspended solids (TSS) effluent limitation of 0.62 kg TSS/kkg
LWK is the average of the values listed in Table 25 for Plants 2,
4, 7, 8, 9, 10, and 11. The TSS value for Plant 5 was not
included because this plant had advanced waste treatment; values
for Plants 1, 3, and 6 were excluded because these values were
unusually low relative to the corresponding BOD5 values for each
plant. A regression equation was developed from an analysis of
treated effluent values for BOD5 and TSS from 30 plants. This
equation predicts, with a high correlation, that the final TSS
value should be greater than the final BODS^ value. In addition,
this regression equation predicts a TSS value of 0.65 kg/kkg,
using the BOD^ effluent limitation value of 0.46 kg/kkg LWK.
This predicted value for TSS agrees well with the recommended
effluent limitation value. Again using the flow value of 28.3 1
(7.5 gal) per bird and an average bird weight of 1.74 kg (3.8
Ib) , this effluent limitation value corresponds to a
concentration of 38 mg/1. Eleven of the twelve plants with TSS
data listed in Table 25 and eleven of the thirty-two plants for
which data were available meet which TSS effluent limitation.
The grease effluent limitation of 0.20 kg grease/kkg LWK is based
upon a limiting effluent grease concentration of 10 mg/1 and the
average water flow per unit of LWK for all chicken processing
plants of 35 1 (9.3 gal) per bird (see Section V). Of the five
plants listed in Table 25, three meet this limitation; of the
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twenty chicken processing plants for which final grease data were
available, nine meet the limitation. The limiting concentration
for grease of 10 mg/1 was also found to be limiting for the red
meat processing industry,19 even though the wastes from this
industry typically have higher raw grease concentrations than do
those from the poultry industry.
Turkey
The BQD5 effluent limitation for turkeys of 0..39 kg/kkg LWK is
slightly higher than the average of the lowest three values
listed in Table 25 for turkey plants. Using the average waste
water flow for turkey processors of 118 1 (31,2 gal) per bird and
an average turkey weight of 8.3 kg (18.2 Ib) , this corresponds to
a final BOD5 concentration of about 28 mg/1,
The suspended solids effluent limitation for turkeys of 0.57 kg
TSS/ kkg LWK is the average of the three lowest values for TSS
listed in Table 25 for turkey plants. Using the average flow per
unit LWK for turkeys, this limitation corresponds to a final TSS
concentration of 40 mg/1.
The grease effluent limitation for turkey processing of 0.14 kg
grease/ kkg LWK was calculated using the average water flow per
unit LWK and the limiting grease concentration of 10 mg/1. Four
of the five turkey plants listed in Table 25 meet this effluent
limitation and the fifth comes very close with a value of 0.17 kg
grease/kkg LWK. These five turkey processing plants were the
only ones included in the study for which data on final grease
loads were available.
Fowl
The BOD5 effluent limitation for fbwl processing of 0.61 kg
BOD5/kkg LWK was obtained by applying to a typical BOD5 raw waste
load of 12,2 kg BOD5/ kkg LWK a waste reduction of 95 percent.
Unfortunately, a comparison with actual performance data is not
possible because no fowl processing plants discharging directly
to surface waters could be located. However, based on the
similarity between fowl and chicken processing in waste water
flows, bird size, and processes employed, this effluent
limitation appears reasonable.
The suspended solids effluent limitation of 0.72 was obtained by
using the regression equation between BOD15 and TSS developed with
data for chicken processing and the BODJi limitation for fowl of
0.61 kg BODj>/kkg LWK. The grease effluent limitation >f 0.15 was
calculated using an average flow of 32.9 1 (8«7 gal) er bird, an
average bird weight of 2.2 kg (4*8 Ib), and a limiting grease
concentration of 10 mg/1. Again, no actual performance data for
TSS and grease were available for comparison.
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Ducks
The BOD^ effluent limitation for ducks of 0.77 was calculated
using the average waste water flow per unit LWK and a limiting
final BODjS concentration of 30 mg/1. The TSS effluent limitation
was calculated using the BOD5-TSS regression equation developed
from waste water data on chicken processing plants and the duck
processing BOD5 limitation of 0.77 kg BOD5/kkg LWK. The grease
effluent limitation of 0.26 kg grease/ kkg LWK was calculated
from the average waste water flow per unit LWK and a grease
limiting concentration of 10 mg/1. One Of two duck processing
plants for which treatment effluent data were available meets all
three of these effluent limitations. This plant meets the
effluent limitations in spite of the fact that the final effluent
included the waste water from an onsite duck feedlot.
Further Processing Only
Since slaughtering processes are not involved, the regression
procedures were not directly applied to this subcategory. The
effluent limitations for further processing plants were based
upon the average waste water flow and final effluent
concentrations of 30, 35, and 10 mg/1 for BOD5, TSS, and grease,
respectively. The BOD^ concentrations are considered attainable
with current technology based on BOD5 reduction demonstrated in
other subcategories with similar raw waste characteristics. The
grease is a limiting value, and a check of validity showed the
TSS concentration corresponds to a value predicted from the BOD5.-
TSS regression equation developed from final effluent data for
chicken processing plants using the BOD5 concentration of 30
mg/1. In addition, all three of these effluent limitation values
are close to those recommended for those segments of the meat
processing industry having operations similar to those of a
poultry further processing only plant,*0
ENGINEERING ASPECTS OF CONTROL TECHNIQUE APPLICATIONS
The specific level of control technology* in-plant primary plus
biological treatment, is practicable because it is currently
being practiced by plants representing a wide range of plant
sizes and types. However, if additional treatment is needed,
such as sand filters, mixed-media filter beds, or microstrainers,
this technology is practical as evidenced by its use in other
industries,1* in municipalities, and in the poultry industry.
PROCESS CHANGES
Significant in-plant changes will not be needed by the vast
majority of plants to meet the limitations specified. Many
plants will have to improve plant cleanup and housekeeping
practices, both of which are responsive to good plant management
control. This can best be achieved 'by minimizing spills,
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containing and collecting materials, and the use of dry cleaning
prior to washdown. Some plants may find it necessary to pretreat
offal holding truck drainage before mixing it with other waste
waters for recycle, after screening, through the feather flume,
and to keep blood segregated from feathers and offal. Some
plants may also find it necessary to use improved gravity
separation systems, such as air flotation with chemical additions
for in-p.1 ant primary treatment.
NONWATER QUALITY ENVIRONMENTAL IMPACT
The major impact on the environment will be disposal of the
sludge from an activated sludge type of treatment system or from
chemical precipitation in in-plant primary treatment. Nearby
land for sludge disposal may be necessary; in some cases a sludge
digester (stabilizer) may offer a solution. Properly operated
activated sludge-type systems should produce well conditioned
sludge acceptable for placement in small nearby soil plots for
drying without great difficulty. it was concluded that the odor
emitted periodically from anaerobic lagoons is not a major
impact.
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SECTION X
EFFLUENT REDUCTION ATTAINABLE THROUGH THE APPLICATION OF
THE BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE—
EFFLUENT LIMITATIONS GUIDELINES
INTRODUCTION
The effluent limitations which must be achieved no later than
July 1, 1983, are not based on an average of the best performance
within an industrial category, but are determined by identifying
the very best control and treatment technology employed by a
specific point source within the industrial category or
subcategory, or by one industry where it is readily transferable
to another. A specific finding must be made as to the
availability of control measures and the practices to eliminate
the discharge of pollutants, taking into account the cost of such
elimination.
Consideration was given to:
o The age of the equipment and facilities involved;
o The process employed;
o The engineering aspects of the application of various
types of control techniques;
o Process changes;
o The cost of achieving the effluent reduction resulting
from application of the technology;
o Nonwater quality environmental impact (including energy
requirements).
Best AvailabJe Technology Economically Achievable emphasizes in-
process controls as well as control or additional treatment
techniques employed at the end of the production process.
This level of technology considers those plant processes and
control technologies which, at the pilot-plant, semi-works, and
other levels, have demonstrated both technological performances
and economic viability at a level sufficient to reasonably
justify investing in such facilities. It is the highest degree
of control technology that has been achieved or has been
demonstrated to be capable of being designed for plant-scale
operation up to and including "no discharge" of r ollutant.s«
Although economic factors are considered in this development, thr-
costs of this level of control are intended to be the top-of-the-
line of current technology, subject to limitation imposed by
economic and engineering feasibility. However, there may be rsorne
technical risk with respect to performance and with respecr to
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certainty of costs. Therefore, some industrially sponsored
development work may be needed prior to its application.
EFFLUENT REDUCTION ATTAINABLE THROUGH APPLICATION OF THE
BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE
Based on the information contained in this section and in
Sections III through VIII of this report, a determination has
been made that the quality of effluent attainable through the
application of the Best Available Technology Economically
Achievable is as listed in Table 26. The technology to achieve
these goals is generally available, and has been used by at least
one poultry processing plant on a full-scale. Plants with onsite
rendering and further processing (but not including cut-up only
operations) in addition to slaughtering require an adjustment in
the BODjj, TSS, and grease limitations. The adjustment for
further processing is the value for further processing only given
in Table 26; the adjustment for onsite rendering includes the
values developed for the off-site rendering industry,39 These
adjustment factors are presented in Table 27. Adjustments for
further processing are only permitted for that part of further
processing that includes cooking. This excludes cut-up
operations. The reason for this is that the raw effluent waste
loads for plants with only slaughtering operations are not
distinctively different from the waste loads of plants with
slaughter plus cut-up operations (see Section IV) . Adjustment
factors for duck feedlots are not included for duck processors
who also raise ducks, because the feedlot industry limitations
require no discharge from duck feedlots by 1983.*i
Adjustment factors do not have a material effect on the
limitations, unless the amount of further processing or rendering
relative to the live weight killed is significant. For example,
if a broiler slaughter operation kills birds of an average weight
of 1.7 kg (3.8 Ib) and renders onsite all of the offal from the
slaughtering operation at the rate of 0.45 kg (1 Ib) offal per
bird, the adjustment factors (AF) are:
AF(BOD5) = 0.07 x 0.45 - 0.018 kg/kkg LWK or 0.018 lb/1000 Ib LWK
1.7
AF(TSS) = 0-10_x 0.45 = 0.026 kg/kkg LWK or 0.026 lb/1000 Ib LWK
1.7
AF(Grease)= O.Q5 x 0.45 = 0.013 kg/kkg LWK or 0.013 lb/1000 Ib LWK
1,7
The adjusted effluent limitations for this plant are the
corresponding limitations from Table 26 added to those AF(s)
above, which are 0.30 * 0.018 or 0.318 kg BOD5/kkg LWK; 0.34 +
0.026 or 0.366 kg TSS/kkg LWK; and 0.20 + 0.013 or 0.213 kg
grease/kkg LWK.
168
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Table 26. Recommended Effluent Limitation Guidelines for July 1, 1983
Industry
Subcategory
Chickens
Turkeys
Fowl
Ducks
Further
Processing
Only
BOD 5
kg/kkg LWK*
0.30
0.21
0.23
0.39
0.15
SS
kg/kkg LWK
0.34
0.24
0.27
0 = 46
0.13
Greasa
kg/kkg LWK
0.20
0.14
0.15
0.26
0.10
NH3
mg/1
4
4
4
4
4
Fecal Coliforms
counts/100 ml
400
400
400
400
400
*kg/kkg LWK is equivalent to lb/1000 Ib LWK.
-------
Table 27. Effluent Limitation Adjustment Factors for On-Site
Rendering and Further Processing*
Effluent
Parameters
BOD5
Suspended
Solids (SS)
Grease
Adjustment Factors
For On-Site Rendering**
0.07 kg BOD^
kkg RM X
0.10 kg SS
kkg RM A
0.05 kg grease
kkg RM
(kkg RM)
(kkg LWK)
(kkg RM)
(kkg LWK)
(kkg RM)
(kkg LWK)
For Further
0.15 kg BODS
kkg FP
0.18 kg SS
kkg FP
0.10 kg grease
kkg FP
Processing
.. (kkg FP)
" (kkg LWK)
.. (kkg FP)
A (kkg LWK)
v (kkg FP)
" (kkg LWK)
*For processes including a cooking step, but not for cut-up only
operations.
**RM—Raw Materials Rendered.
-------
Similarly, the adjustment factors for a broiler operation that
slaughters 73,000 birds per day at an average weight of 1.7 Kg
(3.8 Ib) per bird and further processes 25,000 birds per day with
an average product yield per bird of 0D76 kg (1.7 Ib) FP are;
AF(BOD5) = 0.15
25TQOO x 0.76 = 0.022 kg/kkg LWK
73,000 x 1.74
or 0,022 lb/1000 Ib LWK
AF(SS)
0.18 x 25,000 x 0..76 = 0.027 kg/kkg LWK
73,000 x 1.74
or 0.027 lb/1000 Ib LWK
AF(Grease)^ 0.10 x 25P000_ x. 0.76 * 0.015 kg/kkg LWK
73,000 x 1.74
or 0*015 lb/1000 Ib LWK
The adjusted effluent limitations for this plant would be; 0.30 +
0.022 or 0.322 kg BOD5/kkg LWK; 0.34 * 0*027 or 0.367 kg TSS/kkg LWK;
and 0.20 + 0,015 = 0.215 kg grease/kkg LWK.
In general then, for onsite rendering the adjustment in effluent
limitations is Only significant when a plant renders raw material from
other plants in addition to its own. This practice occurs occasionally
in the poultry processing industry* For further processing adjustment
factors to be significant, a plant would have to further process the
majority of its LWK,
171
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IDENTIFICATION OF BEST AVAILABLE TECHNOLOGY
ECONOMICALLY ACHIEVABLE
The Best Available Technology Economically Achievable includes
the biological treatment systems listed under the Best
Practicable Control Technology Currently Available (Section IX),
and "polishing" by means of a sand filter, microstrainer, or
equivalent following biological treatment. In addition, some
plants will require improved pretreatment, such as dissolved air
flotation with pH control and chemical flocculation, and many
will require ammonia control by nitrification,
nitrification/denitrification or stripping.
In-plant controls and modifications may also be required to
achieve the specified levels. These include the following:
o Appoint a person with specific responsibility for water
management. This person should have reasonable powers to
enforce improvement in water and waste management, both
in-plant and for treatment systems.
o Determine or estimate water use and waste load strength from
principle sources. Install and monitor flowmeters in all
major water use areas.
o Control and minimize flow of freshwater at major outlets by
installing properly sized spray nozzles and by regulating
pressure on supply lines. On hand washers, this may require
installation of press-to-operate valves. This also implies
that screened waste water is recycled for feather fluming.
o Stun birds in the Killing operation to reduce carcass
movement during bleeding.
o Confine bleeding and provide for sufficient bleed time.
Recover all collectable blood and transport to rendering in
tanks rather than i>y dumping on top of feathers or offal.
o Use minimum USDA approved quantities of water in the scalder
and chillers.
o Shut off all unnecessary water flow during work breaks.
o Consider the reuse of chiller water for makeup water for the
scalder. This may require preheating the chiller water with
the scalder overflow water by using a simple heat exchanger.
o Use pretreated poultry processing waste waters for condensing
all cooking vapors in onsite rendering operations.
o In-plant primary systems—catch basins, skimming tanks, air
flotation, etc.—should provide for at least a 30-minute
detention time of the waste water.
172
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o Avoid over-filling cookers in rendering operations.
o Provide and maintain traps in the cooking vapor lines of
rendering operations to prevent overflow to the condensers,
This is particularly important when the cookers are used
to hydrolyze feathers,
o Provide by-pass controls in rendering operations for controlling
pressure reduction rates of cookers after feather hydrolysis.
Cooker agitation may have to be stopped also, during cooker
pressure bleed-down to prevent or minimize materials carry-over.
o Consider dry offal handling as an alternative to fluming. A
number of plants have demonstrated the feasibility of dry offal
handling in modern high-production poultry slaughtering
operations,,
o Consider steam scalding as an alternative to immersion scalding.
o Control water use in gizzard splitting and washing equipment.
o Provide for regular and frequent maintenance attention to by-
product screening and handling systems. A back-up screen may
be required to prevent byproduct from entering municipal or
private waste treatment systems,,
o Treat offal truck drainage before sewering. One method is to
steam sparge the collected drainage and then screen,
o Dry clean all floors and tables prior to washdown to reduce
the waste load. This is particularly important in the bleeding,
cutting, and further processing areas and all other areas
where there tends to be material spills.
o Use high-pressure^ low-volume spray nozsles or steam augmented
systems for plant washdown„
o Minimize the amount of chemicals and detergents to prevent
emulsification or solubilizing of solids in the waste waters,
For examplep determine the minimum effective amount of chemical
for use in the scald tank.
o Control inventories of raw materials used in further processing
so that none of these materials ^;re ever wasted to the sewer.
Spant raw materials should be routed to rendering,
o Separately treat all overflow of cooking broth for grease and
solids recovery,
o Reduce the waste water from thawing operatior ;.
o Make all employees aware of good water management practices
and encourage them to apply these practices.
173
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If suitable land is available, land disposal is the best
technology; it is no discharge. However, biological treatment
may still be required before disposal of waste waters to soil,
although the degree of treatment need not be the same as that
required to meet the 1977 limitations (Section IX). Any of the
systems mentioned in Section IX are suitable.
RATIONALE FOR SELECTION OF THE BEST AVAILABLE
TECHNOLOGY ECONOMICALLY ACHIEVABLE
The rationale used in developing the BODji, suspended solids and
grease effluent limitations presented in Table 26 were based upon
actual performance data of a poultry processing waste treatment
system and upon the average raw waste water flows for each
subcategory. The particular system whose performance was used to
establish these limitations included flow equalization, dissolved
air flotation with chemical addition, activated sludge,
microstrainers, and a chlorination basin. This system was able
to produce an effluent of 15, 18, and 10 mg/1 of BOD5, TSS, and
grease, respectively. Other systems, tut without advanced waste
treatment, were also able to achieve some of these
concentrations, but never all three for any one system.
The Kjeldahl nitrogen, ammonia nitrogen, total phosphorus, and
nitrite-nitrate effluent limitations are based upon transfer of
waste treatment technology from the red meat industry19 and from
the off-site rendering industry.39 These industries, which have
similar raw waste characteristics, were able to reach limiting
concentration values for these waste parameters using similar
waste treatment systems. These limiting concentrations are the
effluent limitation values shown in Table 26. A number of
poultry processing plants were able to achieve these limiting
concentrations. However, the ammonia and Kjeldahl nitrogen
limiting concentrations appear to be the most difficult to meet.
The fecal coliform effluent limitations of UOO counts/100 ml was
established because all plants having adequate chlorination were
within this limit.
Because of the rationale used to establish the 1983 effluent
limitation, two major approaches to reducing the final effluent
waste load can be used by the industry. The first and most
economical approach is to reduce the waste water flow rate to a
value well below the averages found in this study (see Section V)
by the use of in-plant controls and conscientious waste
management. The second is to improve the waste treatment systems
to achieve a greater reduction in waste strength. The most
practical approach however will undoubtedly be a combination of
the two.
174
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AGE OF EQUIPMENT AND FACILITIES
The age of plants and equipment does not affect the end-of-
process pollution control effectiveness„ Although in-plant
control can be managed guit§ effectively in older plants,:some of
the methods capable of reducing the raw waste loads to
realistically low levels may be more costly tc install in older
Plants.
TOTAL COST OF APPLICATION
Based on information contained in Section VIII of this report,
the incremental investment: cost above 1977 costs to the poultry
industry to implement the waste treatment to achieve the 1983
effluent limitations is estimated to be $38=6 million. This
amounts to 6U percent of total capital expenditures of $60
million by the industry in each of the three years 1970, 1971,
and 1972.
The additional operating cost associated with achieving 1983
limitations for chicken^ turkeyF and fowl processors varies from
0.30/bird to 3#/bird and for duck processors from 2.82/bird to
8.2£/bird. Plants that further process only will incur
additional operating costs from 0*29 to 0.730/Kg FP (0-13 to
0.352/lb FP) ,. The total annual cost increase per unit of
production to achieve 1983 limitations varies between 2=5 and 2.6
times the operating cost increase,, The large plants in the
industry will experience the lower cost increase per unit of
production.
ENGINEERING ASPECTS OF CONTROL TECHNIQUE APPLICATION
The specific level of effluent is achievable. Several plants are
currently meeting a number of the 1983 effluent limitations. On«
plant (which includes a microstrainer for advanced removal of
suspended solids) is currently achieving or nearly achieving all
limitations. Howeverff nitrification has been achieved in pilot-
and full-scale units., Denitrification has been explored with
some success in laboratory and pilot-scales. Field sampling
surveys of rendering plants revealed that
nitrification/denitrification was occurring in large lagoon
systems if they were npt overloaded,39 Ammonia stripping may
require pH adjustment and later neutralisation; recent advances
in the operation of the process make it feasible for possible
utilization.
Each of the identified technologies,, except ammonia removal and
nitrification/denitrification, is currently being practiced in
the poultry products industry„ They need to be combined/
however, to achieve the limits specified.
175
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Two poultry plants in our sample are irrigating with their waste
water. Technology for land disposal by irrigation is being used
by rendering plants and by meat processing and meat packing
plants, primarily in the Southwest and California. It has also
been used successfully in northern Iowa by rendering plants and
it is being planned for a packing plant in Iowa. Other
industries, e.g., potato processing, are using it extensively.
Secondary treatment and large holding ponds may be required in
the north for land disposal during about one-half of the year.
Application of technology to reduce in-plant water use will
facilitate land disposal alternatives.
PROCESS CHANGES
In-plant changes will be necessary or will be found to be
advantageous, for most plants to meet the limits specified.
These were outlined in the "Identification of the Best Available
Technology Economically Achievable," previously.
NONWATER QUALITY IMPACT
None of the additional technology required to meet the 1983
limitations is energy intensive. The primary energy consumption
occurs in pumping the waste water and the other material streams
in the treatment processes. Electrical energy usage is expected
to increase about 60 million KWH per year above current (and
projected 1977) levels. This amounts to only about 1.0% of total
power consumption for the industry.
The major impact will occur when the land disposal option is
chosen. The potential long-term effect on the soil caused by
irrigation of processing plant wastes is unknown. On the other
hand, the wastes are among the most amenable to land disposal and
irrigation has been done successfully by one California meat
processing plant for over 30 years. The impact will probably
depend on location, soil conditions, waste strength, climate and
other factors.
176
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SECTION XI
NEW SOURCE PERFORMANCE STANDARDS
INTRODUCTION
The effluent limitations that must be achieved by new sources are
termed performance limitations. The New Source Performance
Standards apply to any source for which construction starts after
the promulgation and publication of the proposed regulations as
Standards. The Standards are determined by adding to the
considerations underlying the identification of the Best
Practicable Control Technology Currently Available, a
determination of what higher levels of pollution control are
available through the use of improved production processes,
and/or treatment techniques., Thus, in addition to considering
th<* best in-plant and end-of-process control technology. New
Source Performance Standards are based on an analysis of how the
level of effluent may be reduced by changing the production
process itself. Alternative processes, operating methods, or
other alternatives are considered. However, the end result of
the analysis is to identify effluent limitations which reflect
levels of control achievable through the use of improved
production processes and practices fas well as control
technology) rather than prescribing a particular type of process
or technology which kirast be employed* A further determination is
made whether a limitation permitting no discharge of pollutants
is practicable.
Consideration must also be given tos
o Operating methods;
o Batchff as opposed to continuous? operations;
o Use of dry rather than wet processes or expanded reuse of
water by cascading through the plant;
o Recovery of pollutants as byproducts.
EFFLUENT REDUCTION ATTAINABL5LFQR NEW SOURCES
The effluent limitations for new sources are the same as those
for the Best Practicable Control Technology Currently Available
(see Section IX). In additionff ammonia effluent limitations are
required* The ammonia limitation is based on an ammonia nitrogen
concentration of 10 mg/1 and the same wast:e water flc rates per
unit LWK as used in Section IX. The new source amm *iia effluent
limitations for the five categories ares
177
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Category
Chickens
Turkeys
Fowl
Ducks
Further Processing Only
Ammonia as N
Effluent Limitation,
Kq/kkq LWK, (lb/1000 Ib LWK)
0.20
0.14
0.15
0.26
0.10
The effluent limitations for ammonia are readily achievable in
newly constructed plants as demonstrated by the fact that a
number of existing well-operated plants are meeting them.
However, the limitations for the Best Available Technology
Economically Achievable should be kept in mind; it may be a more
practical approach to design a plant which approaches the 1983
limitations. Consideration should also be given to land
disposal, which would be no discharge. In some situations this
will be the most attractive and economical option. Estimates of
capital investment cost, operating cost, and total annual cost
for waste treatment by new point sources are listed for each
subcategory in Table 28.
IDENTIFICATION OF NEW SOURCE CONTROL TECHNOLOGY
The technology is the same as that identified as the Best
Practicable Control Technology Currently Available (see Section
IX). However, certain steps that will be necessary to meet the
1983 guidelines should be considered and, where possible,
incorporated. These include:
In-Plant Controls
o Control and minimize flow of freshwater at major outlets by
installing properly sized spray nozzles and by regulating
pressure on supply lines. Hand washers may require installa-
tion of press-to-operate valves. This also implies that
screened waste waters are recycled for feather fluming.
o Stun birds in the killing operation to reduce carcass
movement during bleeding.
o Confine bleeding and provide for sufficient bleed time.
Recover all collectable blood and transport to rendering
in tanks rather than by dumping on top of feathers or offal.
o Use minimum OSDA-approved quantities of water in the scalder
and chillers.
178
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Table 28. Capital Investment, Operating and Total
Annual Costs for New Point Sources
Plant Type
Chicken
Small
Medium
Large
Turkey
Fowl
Small
Large
Duck
Small
Large
Further Processing
Only
Small
Large
Capital
Investment
$470,000
640,000
950,000
400,000
364,000
529,000
227,000
385,000
225,000
364,000
Operating
Cost per Year
$54,000
67,100
90,400
48,300
45,400
59,700
35,300
46,400
35,100
45,400
Total Annual
Cost per Year
$148,000
195,100
280,400
128,300
118,200
167,500
80,700
123,400
80,100
118,200
179
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o Shut off all unnecessary water flow during work breaks.
o Consider the reuse of chiller water as makeup water for the
scalder. This may require preheating the chiller water with
the scalder overflow water by using a simple heat exchanger.
o use pretreated pqultry processing waste waters for condensing
all cooking vapors in onsite rendering operations.
o Consider dry offal handling as an alternative to fluming. A
number of plants have demonstrated the feasibility of dry offal
handling in modern higb-prcduction poultry slaughtering
operations.
o Consider steam scalding as an alternative to immersion scalding.
o Control water use in gizzard splitting and washing equipment.
o Provide for frequent and regular maintenance attention to by-
product screening and handling systems. A back-up screen may
be required to prevent byproduct from entering municipal or
private waste treatment systems.
o Dry clean all floors and tables prior to washdown to reduce
the waste load. This is particularly important in the bleeding,
cutting, and further processing areas and all other areas where
there tend to be material spills.
c Use high-pressure, low-volume spray nozzles or steam-augmented
systems for plant washdown,
o Minimize the amount of chemicals and detergents to prevent
emulsification cr solubilizing of solids in the waste waters.
For example, determine the minimum effective amount of chemical
for use in the scald tank.
o Control inventories of raw materials used in further processing
so that none of |:hese materials are ever wasted to the sewer.
Spent raw materials should be routed to rendering,
o Treat separately all overflow of cooking broth for grease and
solids recovery.
o Reduce the waste water from thawing operations.
o Make all employees aware of good water management practices
and encourage them to apply these practices.
o Treat offal truck drainage before sewering. One method is
to steam sparge the collected drainage and then screen.
o In-plant primary systems—catch basins, skimming tanks, air
flotation, etc.—should provide for at least a 30-minute
detention time of the waste water. Frequent, regular
180
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maintenance attention should be provided.
End-of-Process Treatment
o Land disposal by irrigation should be a primary consideration
wherever possible.
o Sand filter or microscreen following biological treatment of
ef fluent«,
o Solid waste drying, composting, and upgrading of protein
content.
PRETREATMENT REQUIREMENTS
No constituents of the effluent discharged from a plant within
the poultry processing industry have been found which would
interfere withff pass through^ or otherwise be incompatible with a
well-designed and operated^ publicly-owned activated sludge or
trickling filter waste water treatment plant* The effluent,
however^ should have passed through byproduct recovery and in-
plant primary treatment in the plant to remove settleable solids
and most of the grease« The concentration of pollutants
acceptable to the municipal treatment plant is dependent on the
relative sizes of the treatment facility and the poultry
processing plant, and must, be established by the treatment
facility. It is possible that grease remaining in the plant
effluent may cause difficulty in the treatment system; trickling
filters appear to be particularly sensitive, A concentration of
100 mg/1 is often cited as a limitg and this may require an
effective air flotation system in addition to a catch basin. If
the waste strength* in terms of BQD5ff must be further reduced,
any of the various components of biological treatment systems can
be used, such as anaerobic contact*, trickling filter, aerated
lagoonsff etc,e as pretreatment0
181
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SECTION XII
ACKNOWLEDGMENTS
The program was conducted under the overall supervision of Dr. E.
E. Erickson. Robert J. Reid was the Project Engineer; he was
assisted by Messrs. J. P. Pilney and Robert J. Parnow. Special
assistance was provided by North Star staff members: Mrs. Mary
Weldon, Messrs. R. H. Forester, A. J. Senechal, R. F,
Colingsworth, and Dr,. L. L. Altpeter.
The contributions and advice of Mr. Jbhn A. Macon, Mr. William J.
Camp of Gold Kist Poultry and Mr. Gary J. Bottomley of Holly
Farms Poultry are gratefully acknowledged. Also, James and Paula
Wells of Bell, Galyardt, & Wells made invaluable contributions in
numerous telephone conversations.
Special thanks are due Mr. Jeffery D* Denit, Effluent Guidelines
Division for his guidance in the direction of the program and for
his invaluable help in carrying out all aspects of the research
program.
The cooperation of the poultry processing industry is greatly
appreciated. The National Broiled Council, Poultry Science
Association, Poultry and Egg Institute of America, Southeastern
Poultry and Egg Association, Poultry Industry Manufacturer1s
Council, Arkansas Poultry Association, National Turkey
Federation, Pacific Egg and Poultry Processers Association,
Mississippi Poultry Improvement Association, and Alabama Poultry
and Egg Association deserve special m'ention, as do many companies
that provided information and cooperation in plant visits and
onsite sampling programs.
Various offices in the United States Department of Agriculture,
especially the Meat and Poultry Inspection Division, and many
State and local agencies were also most helpful and much
appreciated.
182
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SECTION XIII
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183
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184
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36. "Preliminary Report, 1972 Census of Manufacturers Industry Series,"
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Segment of the Meat Produpts Point Source Category
U.S. Environmental protection Agency, Washington,
August 1974.
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Segment of the Meat Products Point Source Category
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185
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Acidr" presented at 47th Annual Conference, Water Pollution
Control Federation, October, 19"|4.
45. Development and Demonstration of Nutrient Removal from
Animal Hastes EPA-R2-73-095 U. 3. Environmental Protection
Agency, January, 1973.
46. Prakasam, T.B.S. et alr "Approaches for the Control of
Nitrogen With an Oxidation Ditch," Proceedings 1974
Agricultural Waste Management conference, Cornell University,
Ithaca, New York, pp 421-435. j
47. "Control of Nitrogen in Wastewater Effluents," U. S.
Environmental Protection Agency, ORD (NERC) Cincinnati,
Ohio, March 1974.
48. "ABF Nitrification System, 1974 Pilot Plant Study," Interim
Report, Neptune Microfloc, Inc. September, 1974.
49. Reeves, T.G,, "Nitrogen Removal" a literature review,"
JWPCF volume 44, No. 10 pp 1895-1908, October, 1972.
50. Gonzales, J. G. and R. L. Gulp, !'New Developments in
Ammonia Stripping," Public Works p. 78, May, 1973.
51. O'Farrell, T. P. et. al., "Nitrogen removal by ammonia
stripping," JWPCF vol. 44, no. 8 pp 1527-1535, August, 1972.
52. "Nitrogen Removal from Wastewaters," Federal Water Quality
Administration, AWT Laboratory Cincinnati, Ohio May, 1970.
\
53. "Evaluation of Anaerobic Denitrification Processes" Journal
SED, American Society of Civil Engineers pp 108-111,
February, 1971.
54. McLaren, J. R, and G. J, Farquhar, "Factors Affecting Ammonia
Removal by Clinoptilolite" Jour. EED, American Society of
Civil Engineers, pp 429-446 Augus^:, 1973.
55. Johnson, W. K., "Process Kinetics for Denitrification," Jour,
SED, ASCE pp 623^634 August, 1972.
56. "How to Get Low Ammonia Effluent," Water and Sewage Works
p 92, August 1974.
57. Duddles, Glenn A., et.al., "Plastic Medium Trickling Filters
for Biological Nitrogen Control," JWPCF vol. 46 No. 5
pp 937-946, May 1974.
58. Lue-Hing, Cecil, et.al. "Nitrification of a High Ammonia
Content Sludge Supernatent by use of Rotating Discs,"
presented at 29th Annual Purdue Industrial Waste Conference,
May 1974.
59. Haug, R. T. and Perry L. McCarty, "Nitrification with the
186
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Submerged Filter" presented at Annual Water Pollution Control
Federation Conference San Francisco, Ca., October, 1971.
60, Sutton, Paul M., et.al., "Biological Nitrogen Removal - The
Efficacy of the Nitrification Step," presented at Annual
Conference WPCF, Denver, Colorado, October 1974.
61. Lawrence, Alonzo W and C. G. Brown/ "Biokinetic Approach to
Optimal Design and Control of Nitrifying Activated Sludge
Systems "presented at Annual Meeting New York Water Pollution
Control Association, New York, January 1973.
62. Baumann, R. E. and J. L, Cleasby, "Design of Filters for
Advanced waste Treatment" Engineering Research Institute,
Iowa State University,* Ames, Iowa, October, 1973.
63, Rice, G. A. and J. L. Cleasby, "Reported Efficiencies for
Direct Filtration of Plant Effluents/1 Iowa State University,
Ames, Iowa, March 1974.
64. Baumann, R. E., "Design of Filters for Advanced Wastewater
Treatment," Engineering Research Institute, Iowa State
University Ames, Iowa, June 1973.
65. "Water and Pollution Control Technology Report" Neptune
Micro FLOC, Inc., Volume 4, Number 1, September 1970.
66. Weddle, C, L., et.al., "Studies of Municipal Wastewater
Renovation for Industrial Water" presented before Annual
Conference of the Water Pollution Control Federation,
October, 1971.
67. "Comprehensive Monthly Report," Dallas Water Utilities
Department, Water Reclamation Research Center, July 1973.
68. University Area Joint Authority, operating report of
October 6, 1971, State College, Pa.
69. Metropolitan Sewer District, operating report of October,
1971, Louisville, Kentucky.
70. "Upgrading Existing Wastewater Treatment Plants11 U. S.
Environmental Protection Agency Technology Transfer
Process Design Manual, October 1974.
71. Beckman, W. J., et al, "Combined Carbon Oxidation -
Nitrification," Journal WPCF, p 1916-1931 volume 44,
October 1972.
72. Drews, R.J. L.C. and A.M. Greef, "Nitrogen Elimination
by Rapid Alternation of Aerobic/Anoxic Conditions in
orbal Activated Sludge Plants," Water Research
Volume 7, Pergaman Press, 1973.
73. Lynam, B.T. and V.W. Bacon, "Filtration and Microstraining
187
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of Secondary Effluent," from Water Quality Improvement
by Physical and Chemical Processes University of Texas
Press, 1970.
74. Gulp, Gordon L., "Physical Chemical Techniques
for Nitrogen Removal" prepared for EPA Technology
Transfer Seminar, March, 1974.
75. "Ammonia Removal from Agricultural Runoff and
Secondary Effluent by Selected Ion Exchange,"
U. S. Department of the Interior, I^PCA,
Cincinnati, Ohio, March, 1969.
76. "Wastewater Filtration Design Considerations," U, S.
Environmental Protection Agency, Technology Transfer,
Washington, D. C., July 1974.
77. "Upgrading Existing Lagoons," U. S. Environmental
Protection Agency, NERC, Cincinnati, Ohio, October,
1973.
78. Reynolds, J. H., et. al., "Single and Multi-stage
Intermittent Sand Filtration to upgrade Lagoon
Effluents" Utah State University, Logan, Utah,
November, 1974.
79, Middlebrooks, E. J., et. al., "Evaluation of Techniques
for Alage Removal from Wastewater Stabilization Ponds,"
Utah Water Research Laboratory, Utah State University,
Logan, Utah January, 1974.
80. Clark, S. E., et. al,, "Alaska sewage Lagoons," Federal
Water Quality Administration, Alaska Water Laboratory,
College, Alaska, 1970.
81. "Lagoon Performance and the State of Lagoon Technology"
U. S. Environmental Protection Agency, Office of Research
and Monitoring, June, 1973.
82. "Supplementary Aeration of Lagoons in Rigorous Climate
Areas," U. S. Environmental Protection Agency,
October, 1971,
83. "Biological Waste Treatment in the Far North," Federal
Water Quality Administration, Alaska Water Laboratory,
June 1970.
188
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SECTION XIV
GLOSSARY
"Act":
1972.
The Federal Water Pollution Control Act Amendments of
Activated Sludge Process: Aerated basin in which waste waters
are mixed with recycled biplogically active sludge for periods of
about 6 hours.
Aerated: The introduction and intimate contacting of air and a
liquid by mechanical means such as stirring, spraying, or
bubbling.
Aerobic: Living or occurring only in the presence
or molecular oxygen.
of dissolved
Algae: Major group of lower plants, single and multi-celled,
usually aquatic and capable of synthesizing their foodstuff by
photosynthe sis.
Ammonia Stripping: Ammonia removal from a liquid, usually by
intimate contacting with an ammonia-free gas such as air.
Anaerobic: Living or active only in the absence of free oxygen.
Bacteria: Primitive plants, generally free of pigment, which
reproduce by dividing in one, two, or three plants. They occur
as single cells, chains, filaments, well-oriented groups or
amorphous masses.
Biodegradable: The condition of a substance which indicates that
the energy content of the substance can be lowered by tlie action
of biological agents (bacteria) through chemical reactions that
simplify the molecular structure of the substance.
Biological Oxidation: The process whereby, through the activity
of living organisms in an aerobic environment, organic matter is
converted to more biologically stable matter.
Biological Stabilization: Reduction in the net energy level of
organic matter as a result of the metabolic activity of
organisms, so that further biodegradation is very slow.
Biological Treatment: Organic waste treatment in which bacteria
and/or biochemical action are intensified under controlled
conditions.
Blinding: The plugging of the openings in the screen qr metal
fabric that is part of a prqcess screening device.
Slowdown: A discharge of water from a system to prevent a
up of dissolved solids, e.g., in a boiler.
build
189
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BODji: A measure of the oxygen consumption by aerobic organisms
over a five day test period at 20°C. It is an indirect measure
of the concentration of biologically degradable material present
in organic wastes contained in a water stream.
Broiler: A young chicken typically eight to nine weeks old with
an average market live weight of 1,7* fcg (3.8 Ib) ,
By-Products: The feathers, offalf and blood that are recovered
and used as rendering raw materials.
Category and Subcategory: Divisions of a particular industry
which possess different traits £hat affect raw waste water
quality,
Chemical Precipitation: A waste treatment process whereby
substances dissolved in the waste water stream are rendered
insoluble and form a solid phase that settles out or can be
removed by flotation techniques.
Chicken: Often a catch-all classification of both young and
mature fowl including domestic fowl, broilers, fryers, roasters,
and stewing hens; in this report, a specific subcategory of the
industry excluding mature chickens or fowl,
Chilling: In the poultry processing industry, chilling refers to
the processing of rapid cooling of carcasses in ice water
following the evisceration process.
CIP System: "Clean-in-place" equipment and plant cleaning system
using a spray-oh detergent that remains in place wherever it is
sprayed until it is rinsed off.
Clarification: Process of removing undissolved materials from a
liquid, specifically, removal of solids either by settling or
filtration.
Clarifier: A. settling basin for separating settleable solids
from waste waters.
cm: Centimeter.
Coagulant: A material, which when added to liquid wastes or
water, creates a reaction which forms insoluble floe particles
that absorb and precipitate colloidal and suspended solids. The
floe particles can be removed by sedimentation. Among the most
common chemical coagulants used in sewage treatment are ferric
sulfate and alum.
Coanda Phenomenon: Tendency of a flowing fluid to adhere to a
curved surface.
COD-Chemical Oxygen Demand: An indirect measure of the
biochemical load imposed on the oxygen resource of a body of
190
-------
water when organic wastes are introduced into the water. A
chemical test is used to determine COD of waste water.
Comminuted Products: Processed meat products prepared with meat
and fat pieces that have been reduced to minute particle size;
e.g., luncheon meats.
Condoiisables: Rendering vapors capable of being condensed.
Condensate; The liquid produced by condensing rendering cooking
vapors.
Contamination: A general term signifying the introduction into
water of microorganisms, chemical, organic or inorganic wastes,
or sewage, which renders the water unfit for its intended use.
Curing: A process, method, or treatment involving aging,
seasoning, washing, drying, injecting, heating, smoking, or
otherwise treating a product, especially meat, to preserve,
perfect, or ready it for use.
Defeathering: Process of removing feathers from birds.
Denitrification: The process involving the facultative
conversion by anaerobic bacteria of nitrates into nitrogen and
nitrogen oxides.
Digestion: Though "aerobic" digestion is used, the term
digestion commonly refers to the anaerobic breakdown of organic
matter in water solution or suspension into simpler or more
biologically stable compounds or both. Organic matter may be
decomposed to soluble organic acids or alcohols, and subsequently
converted to such gases as methane and carbon dioxide. Complete
destruction of organic solid inaterials by bacterial action alone
is never accomplished.
Dissolved Air Flotation: A process involving the compression of
air and liquid, mixing to super-saturation, and releasing the
pressure to generate large numbers of minute air bubbles. As the
bubbles rise to the surface of the water, they carry with them
small particles that they contact. The process is particularly
effective for grease removal.
Dissolved Oxygen: The oxygen dissolved in sewage, water, or
other liquid, usually expressed as milligrams per liter or as
percent of saturation.
Duck: A type of domestic water fowl with a typical market live
weight of 1.8 to 3.2 kg (4 to 7 Ib).
Edible: Products that can be used for human consvnption.
Effluent:
unit.
Liquid which flows from a containing space or process
191
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Microstrainer/Microscreen: A mechanical filter consisting of a
cylindrical surface of metal filter fabric with openings of 20-60
micrometers in size.
mm: Millimeter = 0.001 meter.
Municipal Treatment: A city- or community-owned waste treatment
plant for municipal and possibly industrial waste treatment,
New Source: Any building, structure, facility, or installation
from which there is or may be a discharge of pollutants and whose
construction is commenced after the publication of the proposed
regulations,
titrate. Nitrite: Chemical compounds that include the N
-------
Polishing: Final treatment stage before discharge of effluent to
a water course. Carried out in a shallow, aerobic laqoon or
pond, mainly to remove tine suspended solids that settle very
slowly. Some aerobic microbiological activity also occurs.
Pollutant: A substance which taints, fouls, or otherwise renders
impure or unclean the recipient system.
Pollution: The presence of pollutants in a system sufficient to
degrade the quality of the system,
Polyelectrolyte Chemicals: High molecular weight substances
which dissociate into ions when in solution; the ions either
being bound to the molecular structure or free to diffuse
throughout the solvent, depending on the sign of the ionic charge
and the type of electrolyte. They are often used as flocculating
agents in waste water treatment, particularly along with
dissolved air flotation.
Ponding: A waste treatment technique involving the actual holdup
of all waste waters in a confined space,
ppm: Parts per million, a measure of concentration usually
expressed currently as mg/1,
Pretreatment: Waste water treatment located on the plant site
and upstream from the discharge to a municipal treatment system.
Primary (In-Plant) Waste Treatment: In-plant materials (grease
and solids) recovery and waste water treatment involving physical
separation and recovery devices such as catch basins, screens,
and dissolved air flotation.
Raw Waste: The waste water effluent from the in-plant primary
waste treatment system.
Recycle: The return of a quantity of effluent from a specific
unit or process to the feed stream of that same unit including
the return of treated plant waste water for several plant uses.
Rendering: Separation of fats and water from poultry offal by
heat or physical energy. "Rendering" operations in the poultry
processing industry also include such operations as feather
hydrolysis and blood processing for animal feeds.
Return on Assets (ROA): A measure of potential or realized
profit as a percent of the total assets (or fixed assets) used to
generate the profit.
Return on investment (ROI): A measure of potential or realized
profit as a percentage of the investment required co generate the
profit.
195
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Reuse: Referring to waste reuse. The subsequent UP? of water
following an earlier use without restoring it. to the original
quality.
Riprap: A foundation or sustaining wall, usually of stones and
brush, so placed on an embankment or a lagoon to prevent erosion.
RM: Referring to the raw material used in the rendering process.
Rot a t i ng B io logic a 1 C on tac tor: A. wa ste treatment device
involving closely spaced light-weight disks which are rotated ( ..
through the waste water allowing aerobic microflora to accumulate
on each disk and thereby achieving a reduction in the waste
content.
1
Sand Filter: A filter device incorporating a bed of sand that,
depending on design, can be used in biological or advanced waste
treatment.
Secondary Treatment: The waste treatment following primary in^
plant treatment. Typically involving biological waste reduction
systems.
Sedimentation Tank: A tank or basin in which a liquid (water,
sewage, liquid manure) containing settleable suspended solids ijp
retained for a sufficient time so part of the suspended solids
settle out by gravity. The time jjlnterval that the liquid is
retained in the tank is called "detention period." In sewag|e
treatment, the detention period is short enough to avoid
putrefaction.
Settling Tank: Synonymous with "Sedimentation Tank." ':
Sewage: Water after it has been fouled by various uses. From
the standpoint of source it may be a combination of the liquid or
water-carried wastes from residences, business buildings, and
institutions, together with those from industrial and
agricultural establishments, and with such groundwater, surfape
water, and storm water as may be present.
Shock Load: A quantity of waste water or pollutant that greatly
exceeds the normal discharged inl^o a treatment system, usually ^
occurring over a limited period of time.
Skimmings: Fats and floatable solids recovered from waste waters
by catch basins, skimming tanks, and air flotation devices. ^
Sludge: The accumulated settled solids deposited from sewage or
other wastes, raw or treated, in tanks or basins, and containing
more or less water to form a semiliquid mass.
Slurry: A solids-water mixture, with sufficient water content to
impact fluid handling characteristics to the mixture.
196
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Small Game: Includes rabbits, pheasants, partridge, pigeons,
squabs and guineas, and is often referred to as other poultry by
the industry.
Stoichoimetric Amount: The amount of a substanqe involved in a
specific chemical reaction, either as a reactant or as a reaction
product.
Surface waters: The waters of the United States including the
territorial seas.
Suspended Solids (TSS)-. Solids that either float on the surface
of, or are in suspension, in water; and whiqh are largely
removable by laboratory filtering as in the analytical
determinant of TSS content of waste water.
Tertiary waste Treatment: Waste treatment system^ used to treat
biological treatment effluent; and typically use physical-
chemical technologies to effect waste reduction. Synonymous with
"Advanced Waste Treatment."
Total Dissolved Solids (TDS) : The solids content of waste water
that is soluble and is measured as total solids content minus the
suspended solids,
Turkey: A type of poultry with an average market live weight of
about 8.2 kg (19 Ib). Market live weight varies, however, from
about 3.6 kg (8 Ib) for fryer-roaster (young) turkeys to about
9,0 kg (20 Ib) for mature turkeys.
Viscera: All internal organs of
evisceration.
poultry removed during
Zero Discharge: The discharge of no pollutants in the waste
water stream of a plant that is discharging into a. receiving body
of water.
Htf
197
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VO
00
TABLE
METRIC TABLE
CONVERSION TABLE
MULTIPLY (ENGLISH UNITS) by TO OBTAIN (METRIC UNITS)
ENGLISH UNIT ABBREVIATION CONVERSION ABBREVIATION METRIC UNIT
acre ac
acre - feet ac ft
British Thermal
Unit BTU
British Thermal
Unit/pound BTU/lb
cubic feet/minute cfm
cubic feet/second cfs
cubic feet cu ft
cubic feet cu ft
cubic inches cu in
-degree.Fahrenheit °F
feet ft
gallon gal
galIon/minute gpm
horsepower hp
inches in
inches of mercury in Hg
pounds Ib
million gallons/day mgd
mile mi
pound/square
Inch (gauge) psig
square feet sq ft
square inches sq in
ton (short) ton
yard yd
0.405
1233.5
0.252
ha
cu m
kg cal
0.555
0.028
1.7
0.028
28.32
16.39
0.555(°F-32)*
0730*8
3,785
0.0631
0.7457
2.54
0.03342
0.454
3,785
1.609
kg cal/kg
cu m/min
cu m/min
cu m
1
cu cm
°C
m
1
I/sec
kw
cm
atm
kg
cu m/day
km
(0.06805 psig +1)* atm
0.0929 sq m
6.452 sq cm
0.907 kkg
0.9144 m
hectares
cubic meters
kilogram - calories
kilogram calories/kilogram
cubic meters/minute
cubic meters/minute
cubic meters
liters
cubic centimeters
degree Centigrade
"meters
liters
liters/second
killowatts
centimeters
atmospheres
kilograms
cubic meters/day
kilometer
atmosyherss (absolute)
square maters
square ceniimetars
metric ton (1000 kilograms)
meter
Actual conversion, not a multiplier
1 *
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