EPA-660/2-75-019
JUNE 1975
Environmental Protection Technology Series
Egg Breaking and Processing
Waste Control and Treatment
Research and Developn
nmental Protection Age
Oregon 97330
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development,
U.S. Environmental Protection Agency, have been grouped into
five series. These five broad categories were established to
facilitate further development and application of environmental
technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in
related fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY STUDIES series. This series describes research
performed to develop and demonstrate instrumentation, equipment
and methodology to repair or prevent environmental degradation from
point and non-point sources of pollution. This work provides the
new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
EPA REVIEW NOTICE
This report has been reviewed by the Office of Research and
Development, EPA, and approved for publication. Approval does
not signify that the contents necessarily reflect the views and
policies of the Environmental Protection Agency, nor does mention
of trade names or commercial products constitute endorsement or
recommendation for use.
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EPA-660/2-75-019
JUNE 1975
EGG BREAKING AND PROCESSING WASTE CONTROL AND TREATMENT
By
W.J. Jewell
H.R. Davis '
O.F. Johndrew, Jr.
R.C. Loehr
W. Siderewicz
R.R. Zall
Cornell University
Ithaca, New York
Grant No. 802174
Program Element 1BB037
ROAP/TASK No. 21 BAA/023
Project Officer
Jack L. Witherow
Pacific Northwest Environmental Research Laboratory
National Environmental Research Center
Corvallis, Oregon 97330
NATIONAL ENVIRONMENTAL RESEARCH CENTER
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CORVALLIS, OREGON 97330
Far «ale by the Superintendent of Documents, U.S. Government
Printing Office, Washington, O.C. 20402
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ABSTRACT
Eleven percent of the eggs produced in the U.S. go to egg breaking
plants to produce more than 800 million pounds of various liquid egg
products annually. This study was conducted to determine the waste-
water problems of this industry, the potential for reduction of waste-
waters by in-plant management methods, and the treatability of the
effluents. This report is divided into three sections - industry re-
view, waste characterization and in-plant control, and treatability.
Five egg breaking plants were sampled which covered a size ranging
from small installations (one egg breaking machine) to one of the
largest (twelve breaking machines). Three facilities were extensively
sampled before and after in-plant management methods were adopted to
determine the effectiveness of source control of wastes. The waste
generation characterization is presented on a unit production basis as
well as absolute quantities and concentration. The effectiveness and
difficulty of achieving various levels of in-plant waste control are
documented.
Five conventional treatment systems were examined in the treatability
study - aerobic lagoons, anaerobic lagoons, activated sludge, rotating
biological contactors, and a system composed of an anaerobic lagoon
followed by an aerobic lagoon. Basic engineering design information
was developed for each process. Recommendations for use of various
processes are made depending on the degree of treatment required.
This report was submitted in fulfillment of Project S-802174 by Cornell
University, College of Agriculture and Life Sciences under the partial
sponsorship of the Environmental Protection Agency. Work was completed
as of August 28, 1974.
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CONTENTS
Section Page
I Summary and Conclusions 1
II Recommendations 7
III Introduction 9
IV Objectives 10
PART I - A BRIEF HISTORY AND FUTURE OF THE EGG
BREAKING AND PROCESSING INDUSTRY
I Importance of the Egg Enterprise 13
II Location and Regional Changes in the Egg Industry 14
III Marketing Channels 23
IV Production, Consumption and Price 25
V Historical and Technological Developments and 31
Their Relation to Operating Problems
VI Future of the Egg Industry 43
PART II - CHARACTERISTICS OF EGG BREAKING AND
I
II
III
IV
I
II
III
IV
V
PROCESSING WASTES BEFORE AND AFTER IN-
PLANT WASTE REDUCTION
Introduction
Field Study Description
Egg Breaking Waste Characterization
Discussion and Observations
PART III - EGG BREAKING INDUSTRIAL WASTEWATER
TREATABILITY STUDIES
Introduction
Theoretical Considerations
Materials and Methods
Results of Treatability Studies
Discussion
PART IV - REFERENCES
PART V - GLOSSARY
PART VI - APPENDICES
47
49
59
92
102
105
112
121
153
160
166
169
iii
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LIST OF FIGURES
Number Page
PART I
1 Distribution of Chickens Three Months Old and 15
Over in the U.S. in 1969
2 Changes in Size of U.S. Chicken Production 16
Facilities with Time
3 Distribution of Facilities Producing Frozen or 18
Dried Eggs or Both Under U.S.D.A. Inspection
in 1969
4 Annual U.S. Production of Liquid Egg Products 19
(Dried, Frozen, and Those Used for Immediate
Consumption) and Number of Plants Under U.S.D.A.
Inspection
5 Commerical Egg Marketing Channels. Numbers 24
Indicate the Percent of the Total Which Follow
a Given Pathway
6 Monthly Variations in United States Egg Product 27
Production (Immediate Consumption, Frozen, Dried)
7 Monthly Processing Rate .of Eggs at Plant E 28
8 The Parts of an Egg 32
9 General Steps in Processing Shell Eggs and Egg 36
Products
PART II
10 Flow Diagram of Product in Egg Breaking Facilities 51
11 Egg Receiving Storage Area for Plant D with Clean 52
"Nest-run" Eggs
IV
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Number page
12 Egg Breakers in Plant D 52
13 Example of Floor Egg Liquid Losses That Can Be 56
Avoided with In-Plant Management
14 Example of Floor Egg Liquid Losses That Can Be 56
Avoided with In-Plant Management
15 Example of Flow Measurement Weir Installed in 58
Plants A, B, and C Utilized for Flow Proportioned
Composite Sample Collection. All Samples Were
Stored in Iced Containers Until the Analysis Could
Be Conducted
16 Example of the Variation of Water Usage and 60
Organic Losses (BODg) in Plant A Before In-
Plant Modifications
17 Example of Water Usage and Organic Losses (BOD5) 61
in Plant B Before In-Plant Modifications
18 Unit Process Contribution of Waste of Egg 63
Breaking Wastes Before In-Plant Modification for
Waste Reduction in Plant A
19 Unit Process Contribution of Waste of Egg 64
Breaking Wastes Before In-Plant Modification for
Waste Reduction in Plant B
20 Mass Balance of Egg Materials in Processing Plant 67
A Before Waste Control Modification
21 Waste Loads Generated From Similar Egg Processing 70
Equipment in Plant B
22 Summary of the Average Organic and Water Volume 87
Losses Before and After Plant Modification for
Waste Control
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Number Page
23 Ratio Values of Average Selected Wastewater 90
Parameter Compared with Average Total Solids
in Plant A
24 Qualitative Relationships Between an Index of 94
Apparent Optical Density and the BOD,, of the
Egg Breaking Wastewater
25 Approximate Sources of Organic Waste Loads 96
Generated in Egg Breaking Unit Operations
26 Bench Scale Model of the Aerated Lagoon Process 113
27 Baffled Aerobic Lagoon Used to Examine the 113
Treatability of Egg Breaking Industrial Wastewaters
28 Laboratory Scale Activated Sludge Unit Used to 115
Examine the Treatability of Egg Breaking Industrial
Wastewaters
29 Rotating Biological Contactor Unit Used to Examine 116
the Treatability of Egg Breaking Industrial
Wastewaters
30 Series Anaerobic Lagoon (20 Day SRT) and Aerobic
Lagoon (6 Day SRT) Used to Examine the Treatability
of Egg Breaking Industry Wastewaters. (The light
beaker contains the feed substrate and the dark
beaker the SS of the anaerobic lagoon.)
PART III
31 Aerobic Lagoon Treatment of Total Egg Breaking
Wastewater from Plant A at 20°C.
32 Aerobic lagoon Treatment of Total Egg Breaking 123
Wastewater from Plant B at 20°C.
vt
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Number Page
33 Determination of Substrate Removal Co- 127
efficients for Aerated Lagoons Treating
Wastewaters from Plants A and B at 20°C
34 Aerated Lagoon Treatment Composed of 5 Cells 128
Connected in Series with a Hydraulic Detention
Period of 2 Days Each at 20°C
35 Activated Sludge Treatment of Wastewaters from
Plant B at 20°C, HRT = 4 Days, SRT = 4 Days
36 Activated Sludge Treatment of Wastewaters from
Plant B at 20°C, HRT = 4 Days, 0C = 10 Days
37 RBC Treatment Characteristics with Wastewaters
from Plant B
38 Series Lagoon Treatment with 5 Day HRT in the 139
First Anaerobic Lagoon at 20°C and 6 Day HRT
in the Aerobic Lagoon at 20°C.
39 Series Lagoon Treatment with 10 Day HRT at 140
10°C in the First Anaerobic Lagoon and 6 Day
HRT at 10°C in the Aerobic Lagoon
40 Series Lagoon Treatment with 20 Day HRT at 141
20°C in the First Anaerobic Lagoon and 6 Day
HRT at 20°C in the Aerobic Lagoon
41 Comparison of Multi-Cell and Single Cell Aerobic 147
and Anaerobic Treatment Processes at 20°C
42 Comparison of the Fate of Solids in Anaerobic 150
Lagoons with 10 day HRT at 20°C .and 10°C
43 Comparison of Clarity of Effluents Produced by 155
Various Treatment Processes
vn
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Number
44 Summary of Effluent Turbidity from Various
Aerobic and Anaerobic-Aerobic Treatment Systems
45 A Recommended Wastewater Treatment System to
Achieve Maximum Organic Pollution Control of
Egg Breaking Wastewaters
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LIST OF TABLES
Number Page
PART I
1 Location of Egg Breaking Facilities in U.S. in 20
Selected Years.
2 Eggs: Production, Consumption, and Retail Price 25
in the United States from 1953-1972.
3 Eggs Used for Breaking: Number, Liquid Eggs 29
Produced, Wholesale Selling Price of Frozen
Eggs, and Estimated Value of Liquid Eggs Pro-
duced in the United States during 1951-1969
4 Composition of an Egg 34
5 Estimated Loss from Shell Egg Damage and Poor 38
Texture in New York State Processing Plants, 1973
6 Comparison of Egg Breaking Plant Wastewater 42
Problems to the Surrounding Community Sewage
Problem for Five Facilities
PART II
7 Size and Type of Egg Processing Plants Surveyed 50
8 Recommendations for Minimizing Waste Generation 68
In Egg Breaking Facilities
9 Characteristics of Total Wastewaters from Egg 71
Breaking from Plant A
10 Characteristics of Total Wastewaters from Egg 72
Breaking from Plant B
11 Characteristics of Total Wastewaters from Egg 73
Breaking from Plant C
ix
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LIST OF TABLES (continued)
Number Page
12 Comparison of Wastewater Mass Balances Obtained 75
For Egg Breaking Operation in Plant A Before
and After Modification for Waste Control
13 Biochemical and Chemical Oxygen Demands of 76
Total Egg Breaking Wastes from Plant A
14 Biochemical and Chemical Oxygen Demands of 77
Total Egg Breaking Wastes from Plant B
15 Weight of Eggs Processed and Fraction of Egg 79
Material Recovered in the Product Calculated
from Mass Balance Data for Plant A
16 Volume and Weight of Egg Breaking Wastes 80
Generated Per Unit Eggs Processed in Plant A
17 Volume and Weight of Egg Breaking Wastes 81
Generated Per Unit Eggs Processed in Plant B
18 Volume and Weight of Egg Breaking Wastes 82
Generated Per Unit Eggs Processed in Plant C
19 Volume and Weight of Egg Breaking Wastes 83
Generated Per Unit Eggs Processed in Plants
D and E
20 Summary Average Unit Production Wastewater 85
Volume and Organics Generated in Egg Breaking
Facilities
21 Wastewater Generation Information from Three 86
Egg Breaking Facilities in the Netherlands
22 Survey of Wastewater Control at U.S. Egg 88
Product Plants
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LIST OF TABLES (continued)
Number PART III Pa9e
23 Summary Aerated Lagoon Characteristics and 124
Removal Efficiencies
24 Aerated Lagoon Influent and Effluent Charac- 125
teristics Treating Wastewaters from Plants A
and B. Lagoon Temperature is 20°C
25 Characteristics of 5-Cell Aerated Lagoon Operated 129
at 20°C With a Total Liquid Retention Period of
10 Days (2 days in each cell)
26 Comparison of One Completely Mixed Unit and 130
Multi-Cell Aerobic Lagoon Treatment of Egg
Breaking Wastes
27 Characteristics of Activated Sludge Treatment 134
of Egg Processing Wastewaters at 20°C
28 Rotating Biological Contactor Treatment Charac- 137
teristics When Applied to Egg Breaking Wastes
from Plant B
29 Treatment of Egg Breaking Wastewaters Using 142
Series Treatment of Anaerobic Lagoons Followed
by Aerobic Lagoons
30 Influent and Effluent Characteristics of Single 145
Cell Anaerobic Lagoons Followed by Aerobic Lagoons
with a 6 Day HRT at 20°C
31 Influent and Effluent Characteristics of Single 146
Cell Anaerobic Lagoons Followed by Aerobic Lagoons
with HRT of 6 Days at 10°C
32 Influent and Effluent Characteristics of a 5-Cell 149
2 Day HRT per Cell Anaerobic Lagoon Followed by
an Aerobic Lagoon with a 6 Day HRT at 20°C
xi
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LIST OF TABLES (continued)
Number
33 Measured Sludge Solids Accumulation Rate in 151
Anaerobic Lagoons
34 Measured Sludge Volume Accumulation Rate in 151
Effluents from 6 Day HRT Aerobic Lagoons
Following Anaerobic Lagoons
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ACKNOWLEDGEMENTS
This report is the product of a multi-disciplinary team that included
representatives from the areas of: Poultry Science, Food Science,
Agricultural Engineering, and Environmental Engineering. The history
and background of the egg production business, prepared primarily by
O.F. Johndrew, Jr. and H.R. Davis, is necessarily a brief overview of
this industry. R.R. Zall was responsible for characterization of the
wastewater problems of the industry and developed in-plant management
concepts for waste minimization. W. Siderewicz was a key individual in
the study as the engineer in charge of in-plant sampling, sample analy-
sis and operation of pilot units in the treatability phase of this
study. W.J. Jewell was responsible for the wastewater treatability
studies and also acted as project coordinator. R.C. Loehr prepared the
initial proposal to the Environmental Protection Agency and assisted in
organizing the initial phases of the project. The authors are appre-
ciative of the advice, contributions and support of the following indi-
viduals: C.J. Barton, D. Brown, R.J. Cunningham, E. Davis, R. Draper,
R. Dil, P. Gellert, G. Grey, R.J. Hynek, C.R. Kilmer, P. Kodukula,
M. Kool, R. MacCrea, J.H. Martin, R. McNamara, J.N. Nickum, R. Ridley,
S. Sotiracopoulos, W.T. Wallace.
Finally the authors appreciate the strong support provided for this
research by Dr. N.L. VanDemark, Director of Research and Prof. E.S.
Shepardson, Head of the Department of Agricultural Engineering and other
administration officers in the College of Agriculture and Life Sciences
at Cornell University.
xi n
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SECTION I
SUMMARY AND CONCLUSIONS
Part I - A Brief History and Future of the Egg
Breaking and Processing Industry
1. Economically, egg production is the most important facet of the
entire poultry industry.
2. Eleven percent of eggs produced in the U.S. go to egg breaking
o o
plants resulting in 2.9 x 10 kg (6.40 x 10 Ibs) of liquid egg pro-
ducts which grossed $195 million in 1969.
3. Egg breaking facilities are usually located close to egg production
areas, are found in most states but are concentrated in the Southeast
and California.
4. Except for the unusual growth rate resulting from World War II
and government support effects, the egg breaking industry, as a whole,
has grown at a linear rate of 1.3 percent per year. Although it is
predicted that this growth will continue for the foreseeable future,
there are some indications that trends may favor an increased rate of
growth. Some large prepared food industries may construct egg
breaking plants to increase efficiency, productivity, and market inde-
pendence, Substitution of liquid egg products for other materials in
such common products as ice cream also may increase the egg breaking
capacity in the U.S.
5. Most egg breaking plants are located in small communities. The
highly contaminated wastewaters generated in egg breaking industries
can cause difficulties in municipal treatment facilities. In the
five egg breaking plants sampled, the wastewater ranged between 8
percent and 1500 percent of the wastes generated from all other sources
in the communities in which they were located.
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6. It is estimated that more than half of the egg breaking facilities
of the U.S., or about 100 separate plants are presently faced with
waste treatment or disposal problems and will require assistance in the
near future.
Part II - Characteristics of Egg Breaking and Processing
Wastes Before and After In-Plant Waste Reduction
1. As in many industries, most of the plant managers did not know,
nor did they have available methods to determine the amount of waste
generated in egg breaking operations. They did realize that their
overall losses might amount to 6 to 10 percent of the total output,
depending, as they thought, on the egg shell strength.
2. Even though egg breaking plants process only 11 percent of the
nation's eggs, and egg grading plants the remainder, losses from
breaking plants exceed grading plant waste by more than ten fold,
thereby presenting an equal or greater pollution potential.
3. Wastewater characterization indicated a highly contaminated dis-
charge with COD's greater than 6000 mg/£, and BOD5 equal to about 602
of the COD. Although the nitrogen content exceeded requirements for
aerobic biological treatment, the wastewater was phosphorus deficient.
It was also slightly deficient in alkalinity required to support ef-
ficient nitrification.
4. Up to 15 percent of the total egg liquid output was lost to the
sewer in plants where good in-plant management was not practiced.
Losses equivalent to 3 eggs for every dozen broken were reported as
maximum losses that occur in plants where no waste conservation
measures were practiced. The average pre-modification product losses
in all five plants sampled was 12.5 percent (by weight) of the pro-
cessed output.
5. The measured average amount of liquid egg recovered per dozen
eggs broken was 0.55 kg (1.21 Ibs) and this represented recovery of
80 percent of the total egg weight.
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6. The average egg liquid loss in a medium size facility (two or
three breakers) represents a decrease in revenue between $500 and
$700 per day.
7. The losses on a product basis averaged as follows: Before in-
plant waste conservation 0.034 kg BOD,./kg egg liquid produced and
wastewater volumes of 7.5£/kg (0.90 gal/1bs) egg liquid produced. In-
plant modifications decreased average BOD,- losses by 50 percent and
decreased wastewater volume by 24 percent.
8. The simpler and inexpensive recommended in-plant controls were
adopted by three plants. The egg washing water is a small volume
and was eliminated from the waste stream in one case. Shell auger
drippings and some other floor losses were relatively easy to control.
However, pipe and pasteurizer flushings were not recovered.
9. In-plant waste control was found to reduce:the waste generated
from an average of 12.5 percent product loss to 6.4 percent product
loss. This is equivalent to additional egg product recovered worth
between $250 and $500 per day in a medium sized breaking facility,
not including the savings from reduction in cost of waste treatment.
10. Adoption of in-plant waste control measures that cost less than
$300 per plant could result in reduction of waste load equivalent to
about two-thirds of that which is technically achievable. Good
plant management appears to be capable of reduction of product loss
to about 5 percent of the liquid egg output. If more extensive and
costly modifications are made to the plant to recover the first
flushing from pasteurizers, pipes, and tanks, the product loss to the
sewer could probably be reduced to less than 2 percent of the output.
11. On a national basis in-plant waste control would result in annual
product recovery of 3.2 x 107 kg (7 x 107 Ibs) of liquid egg of a
quality suitable for animal food which is now lost to the sewer.
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12. The effectiveness of In-plant reduction of waste is not dependent
on the size of the egg breaking operation. The portion of the product
lost in small plants and very large plants was comparable, and dependenl
on the degree of management exercised.
13. The total solids concentration was found to correlate well with
other major pollution parameters such as BOD5. This may be a simple
management tool useful for approximating waste loadings with this
wastewater.
14. A qualitative relationship exists between the apparent color
(not related to Standard Methods definition) and BODg levels of egg
processing wastewater and can be used to estimate egg liquid losses.
Part III - Egg Breaking Industrial Wastewater Treatability Studies
1. Egg breaking wastes as obtained from three facilities, A, B, and C,
were highly biodegradable with no observed toxic effect to biological
treatment processes.
2. High concentrations of organic material were not reduced to levels
acceptable for direct discharge to surface waters in conventional
processes, such as activated sludge and aerobic lagoons; even at low
design loadings.
3. Aerobic lagoons, with hydraulic retention times (HRT) of 30 days
reduced the total COD from 5800 mg/Jl to 1000 mg/fc, and resulted in
a high effluent turbidity.
4. Substrate removal coefficients in aerobic lagoons at 20°C ranged
from 0.58 to 0.76 day .
5. The longest sludge retention time (SRT) of 10 days tested with the
activated sludge process resulted in an effluent quality as follows:
total COD of 1140 mg/£, total SS of 500 mg/£, and turbidity equal to
100 JTU.
6. The activated sludge process had nitrification efficiencies of 5 to
70 percent, and the efficiency in the anaerobic-aerobic lagoon system
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varied from 68 to 95 percent conversion.
7. The rotating biological contactor produced an effluent total COD
p
of 320 mg/fc at loading rates less than 3 Ib COD per 1000 ft per day
thus indicating that this process may require large capital costs for
treatment of these wastewaters.
8. Anaerobic lagoons operated at HRT's varying from 5 to 20 days
produced soluble COD removal efficiencies ranging from 64 to 92 per-
cent at 20°C with a small decrease in efficiency at 10°C.
9. The substrate removal coefficient for anaerobic lagoons operated
at 20°C was 0.63 day"1.
10. When anaerobic lagoons were followed by 6 day HRT aerobic lagoons,
the overall system efficiency COD removal was greater than 98 percent,
at 20°C and 10°C, and at anaerobic lagoon HRT's of 5, 10, and 20 days.
Effluent quality from the aerobic lagoon in a series system operating
at 20°C with a 20 day HRT anaerobic primary unit averaged as follows:
90 mg/s. soluble COD, 13 mg/£ soluble BOD5> 92 mg/a N03-N, 21 mg/s,
NH3-N, and turbidity of 5 JTU.
11. Suspended solids (SS) accumulated in the anaerobic lagoon at the
rate of 4 percent of the SS input at an HRT of 20 days and a tempera-
ture of 20°C in an unit that was not mixed before additions of the
daily feed.
12. The effluent from the aerated lagoon following the anaerobic
lagoon contained well flocculated SS which settled at a high rate,
leaving a clarified effluent with a turbidity less than 10 JTU.
13. The daily accumulated sludge volume settled out of the effluent
from the aerobic lagoon in the series treatment system was equivalent
to about 2 percent of the treated volume.
14. A treatment system composed of an anaerobic lagoon followed by an
aerobic lagoon with sludge recycle to the anaerobic lagoon will re-
sult in a low sludge disposal volume.
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15. Design capacity should be related to maximum production
capacity that can be achieved when eggs are plentiful during the
months of May and June. In most facilities wastewater flows are
very low at night and during weekends.
16. Of the units tested, the combination of an anaerobic lagoon
followed by an aerobic lagoon with a clarifier offers the best
potential to produce an effluent quality acceptable for direct dis-
charge.
17. The activated sludge process, aerobic lagoon alone, anaerobic
lagoons alone, or rotating biological contactors were all found to
be suitable to produce an effluent that would be acceptable for dis-
charge to a municipal waste treatment facility.
18. Odor generation was minimized due to formation of a half inch or
deeper scum layer on the anaerobic lagoon. Although this layer was
always effective in laboratory studies it may not be as effective in
full scale units.
19. Aerated lagoons may require addition of inorganic carbon to
support nitrification.
20. Although the wastewater appeared to be slightly phosphorus
deficient for treatment in higher yield aerobic systems, this factor
did not appear to limit process efficiency in activated sludge.
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SECTION II
RECOMMENDATIONS
1. Information on the economic impact of egg losses and their
relation to in-plant management techniques should be communicated to
egg breaking plant owners and managers.
2. The feasibility of product recovery from egg washing solutions
should be determined.
3. More extensive studies should be undertaken to evaluate the merits
of egg washing in reducing bacterial count.
4. As a temporary solution, egg washing wastewaters should be
segregated and trucked to land disposal sites.
5. The economics and feasibility of recovering the initial cleaning
flushings from pasteurizers, pipes, and product holding tank should be
investigated.
6. Egg breaking plant employees should be trained to recognize the
advantages of recovering human inedible product for use as animal food.
7. A system of liquid level indicating probes should be connected to
product pumps or alarms in order to avoid negligent spillovers from
batch processing tanks in egg breaking plants.
8. The plant's wastewater effluent should be monitored and the results
communicated to the plant personnel as a training aid to emphasize in-
plant management as a waste conservation approach.
9. The promising results of the anaerobic-aerobic lagoon system
obtained in this study indicate that the process should be considered
for full scale application.
10. Further research needs to be conducted to determine the reasons
for the significant difference between effluent quality produced by
the series anaerobic-aerobic lagoon treatment and other conventional
processes such as activated sludge.
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11. Additional studies should be conducted to determine whether
recycle of sludge in the anaerobic-aerobic lagoon treatment system
can effectively control the waste sludge for an extended period of
time.
12. Development of solid-liquid separation processes need to be under-
taken in conjuction with further consideration of aerated lagoons or
activated sludge processes for the treatment of egg breaking waste-
waters .
13. Due to the low loading rate (3 Ib COD per 1000 ft ) necessary
for successful operation of the rotating biological contactor, the
economics of use of this treatment scheme should be further examined
to determine its feasibility as a pretreatment process.
8
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SECTION III
INTRODUCTION
This study of the egg breaking industry is divided into three sections:
a review of the characteristics of the industry as a whole, characteri-
zation and control of wastes in five egg breaking plants, and investi-
gations into the treatability of wastewaters from egg breaking facili-
ties. The data are applicable to a wide range of plant capacities since
detailed industry analyses included the largest and most complex egg
breaking facility even though the majority of information was developed
for facilities with one, two or three egg breaking machines. Although
the waste problems associated with processing eggs to bring them to the
shell egg market were not included, the first steps in shell egg handling
are similar to those used in egg breaking plants. Therefore, portions
of the data developed in this study could be used to approximate the
waste problems of this division of the egg processing industry. The
solid waste problems generated by egg breaking facilities were defined
but the disposal alternatives were not developed in this study.
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SECTION IV
OBJECTIVES
Egg processing industries represent a small portion of the total
industries of the U.S. However, because they are often located in
small rural communities and because their wastewaters are highly con-
taminated they can create significant water quality degradation. It
was the general goal of this study to provide an overview of the
industry which would include practical and inexpensive in-plant waste
management methods and determine the problems of treatment of the
wastes. The specific objectives of this study were to:
1. Describe the characteristics of the industry; past,
present and future.
2. Characterize the wastewaters generated in specific
egg breaking facilities representing small, medium and
large production capacities.
3. Develop in-plant waste management techniques to minimize
the generation of waste material.
4. Conduct treatability tests of actual egg breaking waste-
waters to determine the feasibility of reduction of
pollutants,
5. Use the treatability results to suggest least cost and
low energy consuming processes for treatment of waste-
waters to various levels of contamination.
The information in the following sections support the above objectives.
It will be shown that this industry is growing steadily and that the
combination of good effective plant management and use of simple waste
treatment processes can achieve greater than 99 percent pollution con-
trol at a low cost to the industry. In situations where good in-plant
management is instituted as a major part of the pollution control
program, the decrease in loss of product may have the capability of
10
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yielding a return greater than treatment costs.
The egg industry includes both the shell egg and egg products industries,
and as is true with most businesses, has developed an esoteric language
peculiar to its trade. Whenever possible jargon has been eliminated,
but a list of terms used in the egg industry is included in the Glossary.
11
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PART I
A BRIEF HISTORY AND FUTURE OF THE EGG
BREAKING AND PROCESSING INDUSTRY
12
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SECTION I
IMPORTANCE OF THE EGG ENTERPRISE
The egg industry is, financially, the most important of the various
poultry enterprises. In 1973, the egg, broiler, and turkey enterprises
showed a gross national income of about $6.5 billion and eggs alone
accounted for nearly half this total (1).
Within the State of New York the egg enterprise is even more signifi-
cant since of the $75 million cash receipts received for poultry and
poultry products in 1972, 81% was derived from eggs (2 ). Eggs and
"greenhouse and nursery products" were tied for third in rank in
comparison of cash receipts for all farm marketed commodities.
In the continental United States in 1973 there were 291,827,000 laying
hens which produced 5,544 million dozens of shell eggs or about 6,700
million pounds of egg products. New York State ranked 12th in the
number of layers with 8,916,000 and 13th in number of shell eggs pro-
duced (2,052,000,000) in the nation ( 1).
Of the total eggs produced in the U.S. in 1972, 11% of the shell eggs
produced were broken for use in producing egg products (liquid, frozen
and dried eggs) and the remaining 89% were sold in shell form (3 ).
The value of liquid eggs produced in the U.S. in 1969 was $195,200,000
( 4).
13
-------
SECTION II
LOCATION AND REGIONAL CHANGES IN THE EGG INDUSTRY
SHELL EGGS
Although Figure 1 shows the location of chickens on hand three months
old and over in 1969, it is an indication of the location of egg farms
since the average trucking distance for most eggs is short. The location
of egg farms in 1973 would be about the same as in 1969 excepting that
there would be fewer and larger farms. The highest concentration of
egg production is in the Southeast and California, but the industry is
fairly uniformly distributed throughout the rest of the U.S. except
for little activity in the arid western states. About 40% of the egg
production in mainland United States is in the southern regions.
Over the last 15 years the percentage of total eggs produced in the
South Atlantic region of the U.S. has increased from 12 to 21 percent
of the total. Most regions have remained about the same with six of the
seven major regions of the U.S. producing greater than 14 percent of
the total ( 6). The period between 1969 and 1971 was stable indicating
little shift between regions in the production of eggs ( 6). Although
regional shifts will continue to occur over the next few years, it may
be concluded that these changes will be more evolutionary rather than
revolutionary.
Size of Flock
Small egg laying flocks have been disappearing in large numbers. In
the United States the number of farms reporting chickens on hand
(3 or 4 months old and over) decreased from about 1.2 million in 1964
to around 471,000 in 1969. The trends are summarized in Figure 2.
14
-------
I DOT* 500,000 HEAD
48 STATE TOTAL = 369,999,078
FIGURE 1. Distribution of chickens three months old and over in the U.S. in 1969 (5).
-------
100
90
80
70
60
50
I- 40
o
30
20
10
FARMS WITH CHICKENS
FLOCKS OF 10,000
BIRDS OR GREATER
FLOCKS OF 3,200
BIRDS OR GREATER-
I I
1910 1920 1930 1940 1950 I960
YEAR
1970 1980
FIGURE 2. Changes in size of U.S. chicken production
facilities with time (7)(8)(9)(10).
16
-------
Integration
The egg industry has become more and more integrated in recent years
in terms of its ability to be self sufficient from feed production
through final product packaging and marketing. Using a new model
procedure to measure integration (index of integration) a report pub-
lished by the U.S. Department of Agriculture indicated lower egg pro-
duction in regions where the rate of integration lagged and higher
production in regions where it has been more vigorous (11).
The market egg industry is expected to become more highly integrated
during the 1970's. However, differences between regions will become
less pronounced and integration will have far less effect in causing
regional shifts of output than during 1955-59.
Egg Products
The location of plants producing frozen or dried eggs in the United
States is shown in Figure 3. Due to the mandatory application of the
Egg Products part of the Egg Products Inspection Act in 1971 (12), the
number of plants under official U.S.D.A. inspection has changed as
shown in Figure 4. Comparison of Figures 1 and 3 confirms that plants
producing egg products are generally located in areas of heavy egg pro-
duction.
The number of egg breaking plants for selected years by regions in the
United States is summarized in Table 1. The largest number of egg
breaking facilities was 477 in 1949, with 152 in operation in 1972.
Five plants were in production in New York as of June 1974.
The large number of facilities existing during the days of World War
II resulted from government support programs. Dried whole eggs were
included under the Lend Lease Program in the spring of 1941. The
17
-------
THE 93 PLANTS PRODUCING FROZEN OR DRIED EGGS
OR BOTH UNDER USDA INSPECTION IN 1969
00
FIGURE 3. Distribution of facilities producing frozen or dried eggs or both
under U.S.D.A. inspection in 1969 (4)
-------
UJ
tr
2000
2 1600
O
ID
Q
O
QC ,_ (200
O- >.
UJ <0
- - 800
a
400
UJ
o
o
a:
a.
NO. FACILITIES
500
200
CO
UJ
400 .j
O
g
o
300 ?
100
UJ
cr.
00
o
ui
u.
O
cr
UJ
CD
1920 1930 1940 1950 I960
YEAR
1970
I960
1990
FIGURE 4. Annual U.S. production of liquid egg products (dried, frozen, and
those used for immediate consumption) and number of plants under
U.S.D.A. inspection 03)04).
-------
government then began to purchase shell eggs on the open market at
supported prices to stimulate farm egg production and this stimulated
construction of additional breaking and drying plants (13).
Table 1. LOCATION OF EGG BREAKING FACILITIES IN
U.S. IN SELECTED YEARS (13)
Region
North
Atlantic
East North
Central
West North
Central
South
Atlantic
East South
Central
West South
Central
Western
United
States
1937
23
36
78
1
4
24
30
196
1942
17
26
87
2
8
29
26
205
1949
48
80
213
13
13
55
55
477
1957
26
40
98
5
4
8
32
213
1959
39
40
96
n
4
6
31
227
1961
35
46
89
23
6
8
41
248
Sept.
1972
25
22
38
17
7
5
38
152
i
1972
to
Changes
in no.o
plants
-24
-58
-175
+4
-6
-50
-17
-325
compared
1949
1972 as
f a % of
1949
52
27
18
131
54
9
69
32
Without government purchase of dried whole eggs after 1950, many egg
breaking plants were forced to close. The largest reduction in numbers
took place in the West North Central States and the major percent
decline was in the West South Central States.
20
-------
After the Egg Products Section of the Egg Products Inspection Act
became effective in 1971, the number of breaking plants decreased in
all regions excepting the East South Central States. This decrease
was due to economic and other pressures resulting from breakers com-
plying with the regulations of the Act.
The production of liquid eggs doubled from the early 1950's to the
late 1960's, reaching a peak of 800 million pounds in 1967. During
this period about 5% was used for immediate consumption, 50% was
frozen and 45% dried. As indicated in Figure 4 it is anticipated that
the future growth trends of the egg breaking industry will be linear
as extrapolated from the past. However, development of new products
and markets may substantially increase the market for egg products.
For example, the next section mentions the possibility of using signi-
ficant quantities of egg white in new food products (Appendix B). If new
applications such as ice cream production were developed the growth
rate of this industry could approach large increases of 10 to 20 per-
cent per year. The estimated growth in production capacity will be
linear at about 12 million pounds per year, or 1.3 percent per year
compared to present capacity.
Types of Liquid Eggs
About half the liquid eggs produced are whole eggs and mixed emulsions.
Egg whites account for about 25% and the various kinds of yolks 25%.
All classes of products showed upward trends from 1961-67, but they
are not uniform. The whole egg, with yolks and whites in their natural
proportions, was usually the largest class of product during 1951
through 1969. At times more whites were produced than whole eggs but
in general whites were second to whole eggs in pounds produced. Yolks
showed a strong upward trend from 1959-67 with a decline in 1968-69.
Mixed emulsions trailed the other classes of egg products, but also
showed an upward trend from 1951-67. In recent years sugared and
21
-------
salted yolks have been reported with yolk emulsions and the three
products are now called "other yolk." In frozen form the greatest
production was in whole plain eggs with yolk blends and whole blends
next (4 }.
The difference in value between the various liquid egg products may
indicate the source of some of the potential pollution problems. Sepa-
rated egg whites are now selling for about $0.20 per lb., yolks for
$1.00 per Ib. with whole eggs selling for about $0.40. Not only is it
difficult to detect losses of egg whites, but the economic incentive
to conserve this material is low.
22
-------
SECTION III
MARKETING CHANNELS
The commercial egg marketing channels in the late 1950's and in
the late 1960's are shown in Figure 5. During that period market egg
producers sold the bulk of their output to assembler-packers; whole-
sale distributors were the second most important buyers. The rest went
directly to breakers or circumvented the major marketing channels and
went directly to retailers, consumers and institutional outlets (15).
Egg breakers now get about 60% of their egg supplies from assembler-
packers. Producers and wholesale distributors supply about 20% each.
Once broken, the liquid eggs are eventually sold to firms using liquid,
frozen or dried eggs in manufactured products. These products reach
ultimate consumers through retail or institutional outlets (15).
During the last two decades, there was a drastic realignment of major
marketing channels for shell eggs. The decentralization of grading
and cartoning operations toward country points has been accompanied
by expansion of direct deliveries to retail warehouses and stores by
assembling and packing firms (which now include many more producer-
packers). The latter development has meant that wholesale distributors
in city markets have been increasingly bypassed. In ten years the share
of the commercial market egg supply passing through the hands of whole-
sale distributors has been cut in half (15).
Egg breaking is conducted basically as a convenience in salvaging under-
grades and disposing of seasonal surpluses of off-sized eggs. However,
the present trends are moving towards filling orders on a regular basis
the year around. In order to do this, breakers are buying eggs from
outside the state when needed to supplement the state's supply.
23
-------
LATE 1950'$
COMMERCIAL
EGG SUPPLY
(100)
ro
LATE 1960's
COMMERCIAL
EGG SUPPLY
(100)
ASSEMBLER-
t PACKERS <
(57)
34
WHOLESALE
DISTRIBUTORS
(69)
ASSEMBLER-
PACKERS
(75)
14
WHOLESALE
DISTRIBUTORS
(28)
BREAKERS
(10)
RETAILERS
INSTITUTIONAL
BUYERS(88)
88
CONSUMERS
(90)
BREAKERS
(10)
RETAILERS
INSTITUTIONAL
BUYERS(88)
88
CONSUMERS
(90)
FIGURE 11. Commercial egg marketing channels. Numbers indicate the
percent of the tota.1 whtch follow a gfven pathway (15)
-------
SECTION IV
PRODUCTION, CONSUMPTION AND PRICE
SHELL EGGS
Total egg production and domestic egg consumption in the United States
trended upwards from 1953 to 1972, despite a corresponding decline in
per capita egg consumption (Table 2.) During this same 20-year period,
the average retail price trended downward. Relatively high prices
occurred in 1969 and 1970 but were contrary to trend (6 ). The increases
in total egg production and domestic egg consumption totalled 11%
during the two decades. Total egg consumption is higher only because
of the increase in populations.
• Table 2. EGGS: PRODUCTION, CONSUMPTION AND RETAIL PRICE
IN THE UNITED STATES FROM 1953 TO 1972 (6 }
Year
1953
1962
1972
Total egg
production
Mil. dozen
5,307
5,403
5,897
Domestic egg
consumption
Mil. dozen
4,928
4,998
5,421
Per capita
consumption
Number
379
327
315
Retail price
per dozen of
Grade A large
eqq
Cents/doz.
69.8
54.0
52.4
EGG PRODUCTS
From 1951 to 1969, the fraction of the total eggs used for breaking has
almost doubled. This figure increased from about 6% of all eggs pro-
25
-------
duced in the early 1950's to nearly 10$ in the late 1960's (Table 3).
During the same period wholesale selling prices of frozen eggs showed
a downward trend. However, the estimated value of liquid eggs pro-
duced increased from about $130 million early in the period to nearly
$200 million by the late 1960's ( 4).
Liquid egg production doubled from the early 1950's to the late 1960's
resulting in a peak of 800 million pounds in 1967. Trends were: a
small increase in percentage of liquid eggs used for immediate consump-
tion, a decrease in the percentage of liquid eggs being frozen from
about two-thirds of total liquid production early in the period to about
one-half late in the period and an increase in the percentage of liquid
eggs being dried from about 15% early in the period to nearly 40% in
later years ( 4).
PRODUCTION RATE VARIABILITY
In considering pollution control in this industry one of the most im-
portant characteristics is the high variability of production rate.
The history of this industry revealed that in its early development it
was essentially a scavenger industry operating off surplus egg product-
ion at times of the year when shell egg production was depressed.
Although the industry presently competes for good quality eggs through-
out most of the year or imports the needed amounts, it is still highly
susceptible to availability of supplies and the market. The data shown
in Figure 6 illustrates this variability in the U.S. over a three year
period and Figure 7 summarizes this data for one of the larger facili-
ties sampled in this study. The whole industry faces shortages of raw
material during the winter months of November and December and usually
experiences a maximum production in the late spring and early summer.
A wastewater treatment facility must be designed to handle peak loads
during the period April through June, and be capable of efficient oper-
ation at only half the waste load during the period November through
January.
26
-------
90
ro
-.4
I-
O
!D
O
O
tr
a.
o
O
UJ
80
70
60
50
-; 40
30
I I
I 3
'68
I I I I I I I I 1 I
II I 3 5 7 9 II I 3
'69 '70
TIME OF YEAR, months
'71
FIGURE 6. Monthly variations in United States egg product production
(immediate consumption, frozen, dried) (16).
-------
00
50,000
DATA FROM PLANT E
c
o
£
« 40,000
(O
O
o
t"
^
OC
O
UJ
o
o
cr
CL
UJ
30,000
20,000
10,000
'72
I I I 1
3579
J I I I I
I 3 5 7 9 II I
'73 '74
TIME OF YEAR , months
3 5 7 9 II
FIGURE 7. Monthly processing rate of eggs at Plant E.
-------
Table 3. EGGS USED FOR BREAKING: NUMBER, LIQUID EGGS PRODUCED, WHOLESALE SELLING
PRICE OF FROZEN EGGS, AND ESTIMATED VALUE OF LIQUID EGGS PRODUCED IN THE
UNITED STATES DURING 1951-69 (4).
ro
10
Year
Eggs used for
breaki nq
Liquid eggs
produced
Eggs used for
breaking as a
percentage of
total egg
production
106 (103-casesa)(106 Ibs) (35)
1951
1959
1960
1965
1969
3,821 10,614
6,389 17,755
5,310 14,746
5,730 15,919
5,836 16,212
409
701
582
629
640
6.6
10.1
8.6
8.7
8.5
Wholesale
selling price
of frozen eggs
at New York
City b
(cents per Ib)
34.8
26.0
27.9
25.7
30.5
Estimated
value of
liquid eggs
produced
($1000)
142,332
182,260
162,378
161,653
195,200
*A case contains 30 dozen (360) eggs.
^Poultry Market Statistics, Consum. and Mktg. Sen/., U.S. Dept. of Agr.
-------
USES OF EGG PRODUCTS
Egg products are used mainly by bakers, confectioners, premix manu-
facturers, and food manufacturers of baby foods, noodles and macaroni,
mayonnaise and salad dressings, ice cream and a large variety of other
food products. Only during World War II and relatively recently have
egg products been available in packages of a size for home use.
Different types of "egg" are used for producing certain food products
because of their different functional properties. For example,
egg whites, yolk and whole egg are used for producing many food items
because of their texture and flavor.
30
-------
SECTION V
HISTORICAL AND TECHNOLOGICAL DEVELOPMENTS
AND THEIR RELATION TO OPERATING PROBLEMS
There have been many developments of a historical and technological
nature which have resulted in improved products and greater production
and marketing efficiencies within the egg industry (17). Space does
not permit a detailed discussion of each development. However, consid-
erable insight into the rationale for some of the activities of the
industry can be gained by review of significant developments. A listing
has been included in the Appendix.
PROBLEMS IN EGG PROCESSING PLANTS
There have been many developments that have improved the product and
increased the operating efficiency in egg processing plants. However,
some of these improvements have resulted in, or contributed to, prob-
lems now encountered in processing plants. Different parts of the egg
contribute to some of the difficulties encountered in these plants.
In order to better understand why and how the egg contributes to egg
processing plant problems, knowledge of the egg is desirable. The
composition of the egg gives some background to a better understanding
of the potential pollution problems. For additional detailed biological
and chemical composition of eggs see Stadelman and Cotterill (18).
THE EGG
Structure
The parts of an egg are shown in Figure & The yolk comprises about
31% of the total weight of the egg and the white around 58% of the egg
31
-------
LATEBRA BLASTODERM (GERMINAL DISC)
ALBUMEN
YOLK
CHALAZAE / / VITELLINE MEMBRANE
INNER and OUTER SHELL MEMBRANE SHELL
AIR-CELL
FIGURE 8. The parts of an egg (19).
32
-------
weight. The chalaziferous layer of the white represents about 3% of
the total white (albumen). The chalazae is white fiber that is re-
moved from the liquid egg material by a screening process. In some
cases these screens may be cleaned by hosing the material off into the
sewer. As will be noted in the following section, this is a practice
which loses a salable product and should not be continued.
There are two shell membranes. The inner and outer membranes together
are only about twenty-four ten-thousandths of an inch thick. These
membranes adhere to the shell in the breaking process along with some
albumen. The shell constitutes approximately 11 percent of the egg and
is composed of about 94% calcium carbonate, 1% magnesium carbonate,
1 percent calcium phosphate and 4% organic matter, chiefly protein.
There is a general industry "rule of thumb" which assumes that 83% of
the total weight of an egg ends up as liquid egg. This would therefore
indicate that 6% of egg liquid remains on the broken shell. This liquid
material may be worth recovering in some instances.
Composition
The protein of the egg contains all of the indispensable amino acids in
well balanced proportions for human consumption. Both the thick white
and the thin white are made up of the same proteins, excepting ovomucin
which is contained only in the thick white. The other proteins con-
tained in each include ovalbumen, canalbumen, ovoglobulin and ovamucoid.
The ovomucin gives the structure to the thick albumen.
The important yolk proteins include ovovitellin (about three-fourths
of the yolk) and livetin. The fatty substances of the yolk are mostly
glycerides (true fat), lecithin and cholestrol. Lecithin helps give
the yolk its emulsifying properties. The percentage composition of the
egg is given in Table 4-
33
-------
Table 4. COMPOSITION OF AN EGG (19)
(All values in percent by weight)
Whole egg
White
Yolk
Shell
Water
100 65.5
58 88.0
31 48.0
Calcium
Carbonate
11 94.0
Protein
11.8
11.0
17.5
Magnesium
Carbonate
1.0
Fat
11.0
0.2
32.5
Calcium
Phosphate
1.0
Ash
11.7
0.8
2.0
Organic
Matter
4.0
The fat or oily materials in the egg are important in relation to
pollution control because of the regulations on these materials in
effluents. However, effluent concentration regulations are intended
to limit grease, oils and fats that are petroleum base materials.
Animal and vegetable fats may not be susceptible to these same regu-
lations. One precaution should be noted. This material may coat the
surfaces of treatment units and clog valves and pipes. These coatings
may turn septic and cause very undesirable odors.
SOURCES OF EGGS FOR PROCESSING
Most of the eggs that are purchased by producer-processors and commer-
cial processors (dealers) are obtained from farms that keep their hens
in laying cages. This means that such eggs are usually clean. However,
there are still farms, from which these processors purchase eggs, that
have floor operations. This means laying nests and nesting materials
which provide opportunities for the eggs, lain in the nests, to more
readily have feces and nesting materials on them when they are ex-
posed to processing.
34
-------
Producers who sell eggs market them in one or more of the following
forms:
1) "Nest run" - Just as they are gathered or collected from
cages or nests). They include all sizes and qualities and
are processed later for sale.
2) Washed - Some producers sell eggs, after washing and packing,
to commercial dealers or other processors.
3) Washed and graded - Some producers sell eggs that are washed,
graded (for weight) and packed to commercial outlets.
4) Fully processed - Many producers, particularly in states
such as New York, wash, candle (for quality), grade (weight),
and pack eggs in cartons or loose in cases to outlets such
as stores, restaurants, bakeries, etc.
Egg breakers buy from producers, dealers, other breakers, etc. In New
York State many of the eggs they buy from these people are "nest run"
eggs. Breakers also buy undergrades such as checks, dirties, stains,
odd sized and shaped eggs, rough shelled eggs, etc. While such eggs
might be undergrade, insofar as the shell is concerned, many of them
are of high interior quality.
Breakers also buy top quality shell eggs when they are available at a
discount. To satisfy the demand of some users, for top quality egg
products, breakers are now buying more high quality shell eggs regularly
than they used to 10 or 15 years ago. Although it is a federal re-
quirement that all eggs be washed, it is possible that when breakers
are processing "once washed" high grade eggs and other clean products
that washing may not be necessary. This issue is discussed further in
Part II of this report.
35
-------
PROCESSING PROCEDURES
A simplified processing diagram for shell eggs and egg products indi-
cates the amount of handling to which eggs are exposed (Figure 9).
These procedures vary according to how the processor is going to dispose
of his eggs or product and other factors.
SHELL EGG PROCESSING
COOLER
MECHANICAL WASHER
MECHANICAL CANDLER
I
MECHANICAL GRADER
(WEIGHT)
I
MECHANICAL PACKER
(NOT ALWAYS)
I
COOLER OR TRUCK
t
OUTLETS
LIQUID EGG PROCESSING (20)
COOLER
(SHELL EGGS)
MECHANICAL WASHER
CANDLER
MECHANICAL BREAKING
MACHINE
PASTEURIZER
LIQUID EGG.PACKAGING
^<
FREEZER
I
TRUCK
HOLDING
COOLER
OR
TRUCK
OUTLETS OUTLETS
FIGURE 9. General steps in processing of shell eggs and egg products
36
-------
PROCESSING WASTES
In both shell egg processing plants and in egg breaking plants the
volume of waste is directly proportional to the volume of eggs or pro-
duct produced and the handling procedures. In farm and commercial egg
processing plants the wash water is often disposed of on land areas or
subsurface without runoff, pollution or other problems. Fiber and
plastic products (damaged cases, cartons, etc.) are taken to landfill
areas.
The undergrades (checks, dirties, stains, etc.) are sold at the farm
or plant, or to egg breaking plants within the limits outlined by the
Egg Products Inspection Act (12). Certain restricted eggs as outlined
in the Act, are used for animal food. Those that are illegal to use
for human or animal food are disposed of according to the instructions
of the Act.
PROBLEMS IN SHELL EGG PROCESSING PLANTS
The same general type of problems exist in both shell egg processing
plants and in egg breaking plants. The problems in both types of
processing may be categorized into three broad areas; economic, func-
tional and legal. Since there are some differences between the problems
existing in shell egg processing plants and in egg breaking plants they
are considered separately.
It might be said that the major problem in processing plants today
is a lack of accurate knowledge of where and what the specific problems
are and how important they are. For example, in shell egg plants, stud-
ies conducted in 17 farm processing plants show that the average loss
from shell damage and poor shell texture alone was 9.3% (21). Of this
5.8% was due to shell damage (checks and leakers). Table 5 shows these
losses in percent and the estimated cost of such losses to the shell
egg industry in New York State in 1973.
37
-------
Table 5. ESTIMATED LOSS FROM SHELL EGG DAMAGE AND POOR TEXTURE
IN NEW YORK STATE PROCESSING PLANTS, 1973 (21).
Shell damage
or
Texture loss Loss
(%) ($)
1) Processing damage
a) checks 4.1 1,470,875
b) leakers 1.7 1,545,017
2) Unaccounted for in 3.0 2,726,500
processing
3) Eggs downgraded to B 0.5 51,250
quality because of
poor textured shells
TOTAL 5,793,642
The amount of "egg breakage" in shell market plants depends upon many
factors which include handling, strength of eggshells, environmental
conditions, etc. Handling is a very broad term which not only connotes
"rough handling" by workers but by materials handling and processing
equipment which had been developed to improve the operation efficiency
in the plants. Automatic packers are often the worst offenders in
connection with physical damage, sometimes causing shell damage amount-
ing to 20% of total damage between the time the eggs leave the washers
and the time they are placed in the egg cartons.
Wastewater Contaminants
The contents of the eggs contaminate the wash water and are found in
the effluent being discharged from the plants. Any increase in egg
38
-------
solids in the wash water will increase the BOD (biochemical oxygen
demand) requirements for reduction of wastes to a level acceptable by
authorities. A summary of other contaminants and waste problems are:
-Foreign materials from eggs - feces, pieces of nesting materials
(on eggs from floor operations), feathers, etc.
-Pieces of fiberboard (from egg cases), paperboard and plastic
(from egg cartons), inedible eggs, etc., are problems in that
they must be disposed of properly. This contributes to the
cost of operating the plant.
-Accumulation of "shell sand" (fine dust from shells), that
filters down through the screens under the washers, clogs
traps in the drainage systems.
-Too much water used in a processing plant.
-Disposal of effluent coming from the plants is a major problem.
Depending upon the soils, terrain and the possibilities of
pollution of air or water, various treatments are utilized to
reduce the BOD (biochemical oxygen demand) of the effluent and
odors to an area. These may include daily trucking of the
effluent to spread on land, aeration-oxidation of the effluent,
municipal disposal systems or others. None of these treatments
have been entirely satisfactory for every plant.
-Employees of processing plants are not informed of the pollution
potential of eggs lost to the floor, of pieces of egg cases and
cartons, of other foreign substances, etc. Thus, there is little
effort made to reduce such losses.
-Plant managers themselves do not attempt to monitor or study
the amount of product lost to the floor, or the amount of
foreign materials reaching the floor to drainage systems. They,
therefore do not know what these losses cost them.
39
-------
PROBLEMS IN EGG BREAKING PLANTS
In a recently completed survey of wastewater problems in all egg
breaking facilities in the U.S. it was reported that nearly half the
respondents have wastewater disposal problems (22). About two-thirds
of the total were served by municipal sewers and the remainder by
some type of private system. The most common individual facility
wastewater treatment system reported was the septic tank.
Similar problems listed earlier for shell egg processing plants also
apply to egg breaking plants. Shell egg breakage from washers in
breaking plants would be greater than that from washers in shell egg
processing plants because more checks (crax) and weak-shelled eggs
(salvage) are put through the washers in breaking plants. Several
breaking plant operators in New York State estimated their losses from
egg breaking activities to be between 6% and 10%. In some instances
breaking plants were working under contracts which committed them to
pay for only those eggs that were actually broken. Thus those losses
which occurred in handling and washing prior to breaking did not repre-
sent a loss to the processing facility. Such agreements are counter
productive to pollution control and should be discouraged.
One of the common problems in egg breaking plants is the loss from
product overflow. It was estimated by one worker that egg losses
could be reduced about 50% by improved floor management which would
stop losses such as product overflowing from vats and the salvage of
animal grade foods from areas like auger drippings.
Egg breaking machines are designed so there are no provisions made to
catch drippings from the machine cups as they travel around the "breaker."
Simple collection devices would convert this type of pollution into a
salable product such as animal food.
40
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Waste treatment systems can be simplified if the more concentrated
wastes are segregated and controlled. While there are some attempts
for plant management to salvage some low grade egg products for animal
foods, the value of this approach for plant management is presently
underestimated.
Pasteurizing liquid egg in a plate-type pasteurizer is similar to
that for milk except that lower temperature and more time is required.
After such pasteurization the plates and pipes are still full of liquid
eggs and must be "chased" or flushed with water. If the "chasing" is
not done thoroughly or properly the loss to a small breaker could repre-
sent a considerable amount of his total input (20). Part II of this
study will discuss management approaches to controlling or minimizing
the wastewater generated by the previously mentioned problems.
PROBLEMS CAUSED BY EGG BREAKING FACILITIES
As was noted earlier, egg breaking facilities are distributed throughout
the U.S. and located in many small rural communities. The relationship
of the magnitude of the wastewater disposal problem to the community
sewage problem can be illustrated by comparing the sizes of the five
communities tested in this study to other community characteristics
(Table 6). The average waste discharged from the facilities varied over an
80 fold range. Conversion of the organic waste generated to-a human
equivalent indicated that these industries produced wastes equivalent
to sewage generated by communities varying in size from about 180
people to nearly 12,000. Comparison of this to the organic wastes
generated by the population and other industries indicated that the egg
breaking facility waste comprised between 8 percent and 1500 percent of
all other wastes. In all five cases the management was concerned, and
the problems ranged from the possibility of legal closure of the busi-
ness to the cost which they were paying to obtain permission to dis-
charge to the municipal wastewater system.
41
-------
Table 6. COMPARISON OF EGG BREAKING PLANT WASTEWATER PROBLEMS TO THE SURROUNDING COMMUNITY
SEWAGE PROBLEM FOR FIVE FACILITIES
.£.
ro
Breaking
plant
A
B
Egg breaking
waste discharge
Ib. BOD5
per day
104
258
Sewered popu-
lation and
additional
industry in
community
1400 people
no industry
700 people
no industry
Waste contri-
buted by
population
and industry3
280
140
Type of
treatment
system in
community
trickling
filter
trickling
filter
Egg Breaking
% of total
f
100 Ib BOD*
IUU X Ib BOD,-
of
37
184
Waste
^
plant
remainder
community_
35
no industry
no existing
treatment plant
2436
800 people
2 pipe manu-
facturers
>160 oxidation ditch
unknown quantity (under construction)
by pipe manuf.
1520
938
21,000 people 11,930
4-poultry &
turkey processors
1-sweet potato
canning operation
high rate
trickling filter
7.8
Assume 0.2 Ib BOOg/capita/day
-------
SECTION VI
FUTURE OF THE EGG INDUSTRY
SHELL EGGS
In the next 10 years the number of hens in the United States should
remain rather stable at not over 300 million. In 1973 there were about
292 million hens in the continental United States ( 1 ).
Projections indicate that the output of eggs in the United States is
likely to be between 76 and 84 billion eggs in 1985. This is based on
an assumed production level of 317 eggs per person per year and popula-
tion projections that range from 240.7 million to 263.0 million people.
Part of this increase in production will be the result of an increase
in the rate of lay per hen. This statement is based on an expected rate
of lay of 250 eggs per laying hen, per year, which seems statistically
reasonable and physiologically possible (23).
The figure of 317 eggs per person was based on the observation that
during the years between 1962 and 1970 supplies at levels near 313
eggs per person have resulted in very favorable prices to producers,
while supplies near 322 have resulted in quite unfavorable prices. The
equilibrium level is likely to be somewhere between. About Mlfway
would be 317 eggs. Actual consumption may eventually drop below 317
eggs per person, however, unless innovative ideas are generated to
maintain markets and new uses for eggs £3 )• Tne consumption of eggs
was 292 per person in 1973 with a high during the past 10 years of
324 eggs per person in 1967 ( 1 ).
The trend of a decreasing number of commercial egg farms and an increase
in the size of those farms will continue during the next 10 years but
43
-------
not as rapidly as during the time between 1964 and 1969. During this
period the number of farms reporting chickens decreased by over 61%,
even allowing for an extra month of age (3 months old and over instead
of 4) in 1969.
Factors that may restrain egg production expansion are those that arise
as an area urbanizes; problems of odor and waste disposal. The egg
industry will need to locate in areas where such conflict can be
minimized and they must find economical ways to control odors and
dispose of waste (23).
Under existing conditions of production and distribution, New York
producers within 150 miles of a major market can probably maintain
their present level of output, but producers in more distant regions,
like the northern part of the state, cannot compete (23).
EGG PRODUCTS
Such factors as weight consciousness, health and highly advertised
breakfast cereals, which have helped to affect a decrease in per
capita shell egg consumption may increase the per capita consumption
of egg products in the future. The office workers who do not eat
breakfast, but have pastry and coffee at morning breaks are eating
more processed eggs. A homemaker who bakes a cake from a pre-mix is
using such eggs. Restaurants, hotels, and institutions frequently
use processed eggs because of the convenience. As the number of meals
eaten away from home increases, so does processed egg consumption.
These factors alone would assure continued growth of the egg products
industry (4 ).
However, an additional market potential exists in new consumer products
that are being developed. If more and more of these products are
accepted, per capita consumption of egg products is likely to offset
44
-------
the expected decrease in consumption of shell eggs and will stabilize
the per capita consumption of all eggs.
Projections of production and prices for egg products were made by
Jones (14). He projected quantities of 1.0 billion pounds for 1975
and 1.3 billion pounds in 1980. Reference to Figure 4 indicates that
these values are high according to this data. He estimated the value
of egg products to be $260 million in 1975 and $318 million in 1980.
As with other trends in the egg industry egg breaking plants are be-
coming fewer and larger. If the present trends continue the number of
egg breaking plants in the United States will drop from 152 in 1972 to
an estimated 108 in 1985. The number of breaking plants in New York
State conceivably could be reduced from 5 (1 plant part time) to 1 or
2 by 1985. These larger egg breaking plants will have increased
problems with waste disposal and odors than do the smaller plants now
in existence.
45
-------
PART II
CHARACTERISTICS OF EGG BREAKING AND PROCESSING WASTES
BEFORE AND AFTER IN-PLANT WASTE REDUCTION
46
-------
SECTION I
INTRODUCTION
GENERAL
Disposal and treatment of wastes from egg breaking plants seriously
trouble the poultry industry. Historically, egg wastes were trouble-
some to treat, but the disposal of the residuals is now further compli-
cated by upgraded sanitation edicts in the Federal Egg Products Inspection
Act of 1970. It has been estimated that about 4 to 25% of all egg
breaking stock is wasted to sewers (22).
LOCATION
Five egg processing plants were examined in this study. Three were
smaller plants located in upstate New York, and two larger egg breaking
operations were briefly visited and sampled in Georgia and Arkansas.
Four of the five plants discharge their wastewater to municipal treatment
facilities and the other has its own state approved system.
The three New York plants were studied in greater detail than the other
two. A minimum of six days of 24 hour sample collections were used in
the New York State facilities to define the wastewater characteristics
to enable reliable estimations of the waste loads before and after in-
plant modifications. Two days of sampling ware needed to develop data for
each of the two plants outside New York. Eighteen days of sampling pro-
vided information on waste characteristics for the most intensively
examined facility.
PROJECT APPROACH
All plants were examined for total plant losses as well as unit process
47
-------
losses in order to identify in-house sources of waste. Methods to
reduce wastes through in-plant modifications were suggested and imple-
mented. Later, the sites were sampled again to measure the effects of
the changes through repeated plant wastewater surveys.
The wastes were physically, chemically, and biologically characterized
to provide data for treatability studies.
Waste and water from all plants were compared on an equal basis to deter-
mine the relationship between plant size and magnitudes of product
losses and water usage.
48
-------
SECTION II
FIELD STUDY DESCRIPTION
DESCRIPTION OF PROCESSING PLANTS
A summary of the equipment used and type of product processing performed
at the five plants surveyed is contained in Table 7. Independent of the
plants' size, it was observed that the plants' layout and mode of opera-
tion were nearly identical. The flow diagram of an egg breaking opera-'
tion in Figure 10 illustrates the various operations involved in pre-
paring liquid, frozen or dried egg products from shell eggs. The first
step in the operation is receiving the cartons of eggs from shell egg
distributors. The eggs, which may have come from a distributor within
a thousand mile radius, are stored in a cool humid climate to maintain
egg freshness and minimize evaporation of water from the egg contents.
Figure 11 is a photo of good quality nest run eggs in the storage area
of Plant D. Egg cases, containing 15, 20 or the more usual 30 dozen per
case, are manually loaded onto a system of rollers which carry them to
the egg washer.
Upon reaching the washer, eggs are manually loaded onto a conveyor belt
of rubber rollers. It is the duty of the person at this point of the
operation to inspect the eggs and remove any "leakers" which are broken
shell with contents exposed. Once a case of eggs has been loaded onto
the washer, the empty cartons and filler flats are set aside to be
returned to egg distributors, bailed for sale as scrap paper products
or trucked to a sanitary landfill site. As the eggs move through the
washer they are scrubbed by brushes moving in a vertical direction. At
the same time warm water is being pumped from the washer's holding tank
and sprayed across the surface of the eggs. This water contains deter-
gents, defoaming agents, egg solids, egg shells and foreign material
removed from the shell surface. The washing equipment contains about
49
-------
Table 7. SIZE AND TYPE OF EGG PROCESSING PLANTS SURVEYED
Type
Plant No. of egg No. of egg No. of egg of product
identification washers breakers pasteurizers processing
A 111 Frozen yolk,
white and
whole egg
B 231 Frozen yolk,
white and
whole egg
C 111 Frozen whole
egg, liquid
whole egg
(bulk tank)
D 12 12 3 Frozen whole
egg, dried,
yolk and
white and
whole egg
E 882 Liquid, yolk,
white and
whole egg
(bulk tank
transport
as liquid)
a 50 gallon volume which is continually recycled for a four-hour period
and then drained to the sewer system. The cleaning equipment is then
refilled for another four hour egg breaking period. Once the eggs have
passed through the scrub brushes they are conveyed above a series of
brilliant lights for inspection in a candling operation. At this point
inspectors remove leakers, blood spot, broken shells from eggs whose
contents have been lost to the washer and eggs of poor interior quality.
These inedible eggs are collected in segregated large containers for pet
food products. It is also at the candling location that dirty eggs are
50
-------
DAM AGE p_C_A R TOO N S_
DROPP_Ep_AND
" ~RE~JEcfElfEGGS
| BROKEN EGGS,_plRT, a
WASHING COMPOUNDS'
AND
WAShlNG
or
Ul
UJ
I-
co
MEMBRANES,
"*"CH~ALAZAE~ 8 SHELLS
I
_ LEAKAGE a j
CLEANUP WATER ,
PASTEURJZER
"STA"RT "a s"roP '
i
CLEANUP WATER
WHOLE EGG
FOR
DISTRIBUTION
i
I EGG CARTON?
RECEIVINGS
STORAGE
LANDFILL
SHELLS a EGGS
WASHER
I
CANDLE
DIRTY
EGGS
SHELLS 8 EGGS
BREAKER
I
SHELLS a EGGS
SNIFF TANK
SEPARATE
(INEDIBLE)
STRAINER
HOLDING
TANK 40°F
BLEND
TANK
PASTEURIZER
CAN OFF
INEDIBLE
EGGS
FREEZER h*
•*• DRIED
ANIMAL FOOD
DISTRIBUTION
RECOVERY
FIGURE 10. Flow diagram of product in egg breaking facilities.
51
-------
FIGURE 11. Egg receiving storage area for Plant D with
clean "nest-run" eggs.
FIGURE 12. Egg breakers in Plant D,
52
-------
removed to be rewashed and at the same time places exceptionally clean
eggs onto the conveyor belt where vacancies exist. Just before the eggs
enter onto the breaking machine they are rinsed with a chlorine spray
containing 150-200 mg/£ chlorine. This rinse along with a spray rinse
which proceeds the scrub brushes constitute a continuous overflow of
water from the washer.
Eggs are automatically loaded onto a rotating egg breaking machine.
Figure 12 shows the 12 breakers in operation at Plant D. The contents
separate from shells and fall into stainless steel cups which are tilted
forward to allow the egg white to drain from yolk portions into a second
cup. As the cups move around the machine they are tripped to either
collect yolks and whites separately or tripped to combine the two por-
tions into whole liquid eggs. As the breaking machine continues rotation,
the empty egg shell discharges from the machine by a strong air blast.
After shell rejection, the mechanism which held the shell is automatically
sprayed with water in preparation for receiving the next whole egg.
Breakers in plants cooperating with this study operated at a rate of 40
cases/hour which means that the employee at this machine must examine
eggs at a rate of 4 per second. The employee operating the breaking
machine has the responsibility to 1) remove eggs containing blood spots,
2) remove spoiled eggs and the cups into which they were broken, 3) manu-
ally break open any eggs which were not broken by the machine, 4) remove
shell fragments which fall into the egg contents, and 5) trip the stain-
less steel cups to a full down position to be washed when they appear
dirty or when no egg was released into the cups. If the USDA inspector
notices dirty eggs on the breaker he may stop the operation and order
the complete machine cleaned. If the plant is not adequately equipped
for pollution control all the contents of the egg breaking machine at
this point may be washed into the sewer instead of being saved for
animal food or some other by-product.
53
-------
Egg meats from the breaking machine operation collect in a small surge
vat, and are pumped from the small vessel to a large sized sniff tank.
The resident USDA inspectors require that this tank's drainage valve be
closed until the sniff tank is full. After the sniff tank is physically
examined by smell to be sure the product does not possess obnoxious odors,
sugar, salt, and other condiments may be added to the product. The con-
tents are drained through a coarse screen filter which retains shell
fragments and the egg's chalazae. Food grade pumps transfer egg product
from the strainer to a refrigerated holding tank (4.4°C).
Once enough product has been collected to ensure continuous pasteurization,
it is pumped as a batch from the holding tank to a different blend
tank where condiments or preservatives are added, if they were not added
previously. When additives are not used the blend tank is by-passed and
the product is sent directly to a small balance tank which preceeds the
pasteurizer. Plate pasteurization requires temperatures ranging from
56°C to 63°C and holding times from 3.5-6.2 minutes depending on the
type of product processed.
The pasteurized product is cooled to 4.4°C in a closed system of cooling
plates from which it is pumped to a separate sanitary can-off room.
Automatic filling machinery is used in this room to package egg meats in
13.6 kg (30 Ib) cans, 1.9 liter (1/2 gallon) cartons or 4.5 kg (10 Ib)
plastic bags. Filled containers are prestacked on pallets in such a
manner as to allow free circulation of air because the pallets are to be
placed in freezer area. Freezing the final product prevents product
degradation through bacterial growth from post-pasteurization contami-
nation which in turn would require reprocessing.
The daily clean-up operations are one of the main sources of wastewater
generation. Before work starts in the morning, the resident USDA inspec-
tor examines all machinery and its surroundings to be sure it is
54
-------
thoroughly cleaned and free of egg solids from the previous day's work.
The breaking machine, all vat pipes and pumps are sanitized with chlorine
solutions prior to beginning the process. After four hours of operation,
plant production is stopped because microbial buildup occurs and sanitary
rules mandate that egg breaking areas be washed and sanitized. The egg
washer is drained, cleaned and refilled. The egg breaker is scrubbed and
spray cleaned. The vat, which holds eggs as they come off the breaker,
is pumped dry of product and then rinsed clean as is the sniff tank and
strainer. Frequently substantial amounts of egg product remain in the
vats, filters and pipes which are flushed onto the floor. After the
machinery is cleansed it becomes necessary to wash down the floors to
rinse away egg residuals, shells, and cleaning liquids. Normal produc-
tion continues for another four-hour period when production is stopped
by another clean-up procedure. At the end of the work day there is a
final complete and intensive washdown which is similar to the noontime
clean-up except that the breakers are scoured and steam cleaned manually.
Vats, pipes and the pasteurizer are cleaned in place with high speed
pumps that circulate detergents and washwater through closed loop systems.
Figures 13 and 14 indicate the types of floor losses that might be
avoided with careful in-plant management.
As previously mentioned, low quality eggs are segregated from breaking
stock at the egg loading and candling operations and occasionally in the
breaking operations. Human inedible liquid product can be sold to animal
food producers once the shell fragments have been removed. In the plants
surveyed three methods were used to separate liquid egg from its shell:
1) inclined shell auger, 2) centrifuging, and 3) commercial produced egg
shell strainer.
SITE PREPARATION
Frequently, food plants use municipal water for the majority of their
water and simultaneously supply its refrigeration plant with private
55
-------
FIGURE 13. Example of floor egg liquid losses that can
be avoided with in-plant management.
FIGURE 14. Example of floor egg liquid losses that can
be avoided with in-plant management.
56
-------
unmetered well water for cooling or wash-up water. Since undetected
sources of water can easily dilute wastewater to be sampled and thereby
indicate an erroneously low wastewater strength, weirs were used to
supplement the metered water use to measure total flows in order to
monitor a plant's total discharge. After locating all pipelines which
carried wastes and the floor drains (except employee restrooms), excava-
tion was made and a weir box, of specific dimensions, was fitted into
position (Figure 15). The weir was then calibrated to be sure that hand-
book values of flow vs. height of weir overflow were identical to known
flows through the weir (24).
57
-------
FIGURE 15. Example of flow measurement weir installed in Plants
A, B, and C utilized for flow proportioned composite
sample collection. All samples were stored in iced
containers until the analysis could be conducted.
58
-------
SECTION III
EGG BREAKING WASTE CHARACTERIZATION
WASTEWATER SAMPLING - BEFORE IN-PLANT MODIFICATIONS
External Measurements
Waste flows were measured at the point of discharge of each unit operation
without alerting the normal plant operation. The goal was to gather base
data at each plant in terms of water volumes, waste strength and chemical
composition of materials wasted.
Wastewater samples collected at the outfall sampling stations were
obtained by two methods. Grab samples were collected at half hour
intervals and proportioned into a composite sample according to flow
volumes during the same half hour period. An automatic sampler was
also set to collect and combine nine equal sized samples per hour. All
samples collected during the study were stored in iced-filled styrofoam
coolers to minimize the biological degradation of the samples and chem-
ical analyses were usually completed within 24 hours. Results of base-
line flow characteristics and waste losses for Plants A and B are shown
in Figures 16and 17. This is the type of information that was developed
for all five plants for at least two days and in some cases, 12 or more
days.
The variability of water usage and BOD5 losses confirms that the batch
type operations of egg processing generate widely varying concentrated
wastewaters. The water usage is greatly affected by minor clean-ups in
the small facilities (Plant A in Figure 16). In larger facilities
(Plant B with three breakers in Figure 17)» the fluctuations in flow
pattern is somewhat dampened by the continuous water usage of three
breaking machines.
59
-------
1000
en
o
o
o»
•»
UJ
UJ
CD
or
<
X
o
w
DC
UJ
h-
800
140
120
UJ 100
600
or
u
-------
2000
o
o»
1600
en
id
O
CO
1200
Q 800
LJ
<
5 400
h-
— 200
|60
UJ
— 120
UJ
o
(C
<
- 80
o
g 40
— WATER
- BOD5
8
9 10
AM
II 12
6 7
PM
8
10
TIME OF DAY , tours
FIGURE 17. Example of water usage and organic losses (BOD,-) in Plant B before
o
in-plant modifications.
-------
Internal Measurements
In order to determine specific locations of waste loads in an egg pro-
cessing plant, it was necessary to sample measurable losses of unit
operations. In Plant A this included collecting weighted composite
samples of the egg washer overflow and sump contents, continual overflow
from the egg breaker and flushings of vats, tanks, strainers, piping and
pasteurizer. Other sources of wastes include rejected inedible eggs
from the washer and breaker operations that are not deposited in the
proper receptacles, egg product dripping from the breaking machine, mal-
functioning egg loading device on the egg washing machine, leaking pumps
*
and piping connections and vat spillovers. All of the latter losses are
examples of unmeasurable losses which constitute floor losses. In Plant
B similar composite samples as noted above were obtained from both washers,
three breakers, and a sump line which corresponds to losses of egg over-
flowing from the base of an inclined shell auger. All other losses were
considered floor losses. There were no internal premodification measure-
ments for Plant C during the 1972 study by Zall and Toleman (25 ).
Losses, before in-plant modifications, are shown in Figures 18 and 19.
It can be seen that egg washers contribute at least 25% to a plant's
total BOD loss, yet it constitutes only 5-10% of the plant's total water
usage. Being such a highly concentrated unit loss suggests that it could
be segregated from the plant's waste stream and disposed of separately.
The large amount of wastes generated from "floor losses" would indicate
that in-plant conservation methods should be effective in decreasing
wastes.
In both plants it was noticed that egg breaking machines were operating
with faulty flow valves and therefore using excessive amounts of water.
This is evident from the fact that egg breakers utilized 25-33% of a
plant's water consumption.
62
-------
U)
>_ 6000
O
Q 5000
Uf
— o
ID
2 100
—
—
—
!-M
X-
:•:•
>:;-
::>:
" 'X
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;;'-:
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"'.'".
;•;
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r^i
ij§
;£;
;:•:«
:•:;
:>:;
"\ '
-T
x;
; .".;
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pfe™
t"-'J {**' 1
HIGH
^AVERAGE
WATER BOI
:¥ v •:•:; = T
iij: ^ : 1 i:j: E j
,•,«. /^ , 1 •.;. . •
ciJ ^ uJ Xi ^ ill J?fr7Vf» E?i >••
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?
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::':;',
'*•*"
""'-"":
.-.-
'•
";:
:•:
V
'." J
•X
'',"•
TOTAL PLANT
WASTE
WASHERS
BREAKERS
TANKS, PIPES, FLOOR LOSSES
ETC.
FIGURE 18. Unit process contribution of waste of egg breaking wastes before
in-plant modification for waste reduction in Plant A.
-------
Hi
I •
VOLUME AND CONCENTRATION OF EGG BREAKING WASTES
BEFORE CONSERVATION PROGRAM IN PLANT B
BOD,
rO
l
O
- 14
X
>
0 12
\
O
LJ
co 10
tr
LJ 8
H
^
^
U_ 6
O
(O
Z 4
O
1
^^J
< 2
0
— J 700
— Q 600
LJ
O
_]j
— 0 500
O
OC
Q.
— « 400
O
O
CD
— ^ 300
O
CO
— Q 200
z
^7?
— 2 100
— •
—
—
—
—
—
—
~
'_ "_
|
x
'•:'•
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:•:
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-/.
' '_-
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:::
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:'•:•
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-:
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—
u<
AVERAGE
T
.;'
:•;.
I
0
w
—
~-
w
WATER
--
iiji
x
:x
•:•
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:--:
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:-:,
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TOTAL PLANT WASHERS BREAKERS
Pta
:•:•
SUMP
1_
:':
'•
'.:
x
•i
'
.
X
-_.
'•.'•
-\'
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:::;
::::
:x
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;';:
;:•:
"-"-
";
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1 r
.'•-
-V
FLOOR LOSSES
WASTE
FIGURE 19. Unit process contribution of waste of egg breaking wastes before
in-plant modification for waste reduction in Plant B.
-------
In plant A the total amount of egg product that was judged to be sal-
vageable from pipes, pasteurizer strainer and vats, represents nearly
10 percent of Plant A's total BOD losses. In Plant B the unit loss
designated as a sump loss is actually spillover of liquid egg from the
base on an inclined auger carrying empty egg shells to a refuse truck.
This waste source is easily converted to a salable by-product, and in
plant B represented 20 percent of the total BOD.
The most significant loss in both plants was floor losses which contrib-
ute about 50% to a plant's total BOD loss. These unmeasurable losses
result from malfunctioning equipment, leaking product pumps and piping,
product spillover and plant clean-up. These losses for the most part
indicate a need for more efficient working procedures and additional or
modified equipment. These losses can be decreased through better on-job
employee tratning and process modifications that stress improved product
yields.
IN-PLANT MODIFICATIONS
After a plant's total losses and location of loss were determined,
recommendations were made to alter the operating procedures to minimize
waste production. Informing management of the weight of BOD5 lost in
their operation does not give them a clear understanding of their losses.
A much more effective approach is to relate BOD or COD losses to the loss
of egg product that can be easily translated to dollar losses. Although
it is difficult to achieve, construction of a mass balance indicates the
relationship of various losses to the final product. Enough data were
obtained in this study to approximate a mass balance for plant A using
the following approach.
The total input weight of incoming eggs to be broken was obtained from
plant records. By subtracting the weight of the egg cartons, filler
flats and pallet from the shipping weight of the eggs, the weight of
65
-------
the shelled eggs to be broken was obtained. Losses to the landfill were
calculated assuming that the egg shell constitutes 11% of an egg's total
weight and that 1.75% of an egg's liquid weight adheres to the shell
after it is broken open and drained (26). The weight of inedible egg
product, after being centrifuged to remove the shells, along with the
weight of final product was also obtained from plant records. Losses
of eggs to the sewer were calculated by knowing the volume of COD con-
centration of Plant A's wastewater, along with the COD and density of
raw egg. The data shown in Figure 20 are an average of three separate
days of sampling in which the total weight of material passing out of
the plant checked within 5 percent of the total input. This type of
data impressed management because it indicated that the egg loss repre-
sented greater than 8% of the plant's edible product output, and in this
instance, represents a daily loss of about $435 (assuming a market value
of $1.10 per kg [$0.50 per lb]). When it was noted that egg losses were
substantial and'resulted in decreased profit, plant managers were quick
to understand the problem and were anxious to implement suggested in-
plant modifications.
EFFECTS ON IN-PLANT MODIFICATIONS
Internal and External Measurements
Management at all three New York egg breaking plants agreed to implement
some modifications suggested for waste control as given in Table 8.
Although the degree to which the recommendations were adopted cannot be
determined, the majority of the plants implemented those identified as
2, 3, 4, 6, 11 and 13 in Table 8. Based on previous data it was clear
that eliminating the washer water, efficient recovery of discarded eggs
(leakers, etc.) and recovery of the egg shell auger drippings would
greatly reduce the effluent BOD. In essence each plant manager adopted
the changes which he could implement quickly at a low cost without
interrupting production. It was estimated that the cost of adoption
66
-------
CD
EGGS BROKEN
(EGGS 8 SHELL)
5952 kg(l3,M9 Ib)
100%
EGG
PROCESSING
PLA
LANDFILL
SHELLS 658kg(l443lb)
ADHERING
EGG PRODUCT
12.2 %
INEDIBLE
EGG PRODUCT
3.4%
213 kg (470 Ib)
EDIBLE FOOD
PRODUCT
4896kg (10,790 Ib)
78.2%
394kg (864 Ib)
6.3%
FIGURE 20. Mass balance of egg materials in processing Plant A before
waste control modification.
-------
Table 8. RECOMMENDATIONS FOR MINIMIZING WASTE
GENERATION IN EGG BREAKING FACILITIES
1. Minimize use of improper stacking of eggs in storage, or weak
storage boxes.
2. Minimize number of times eggs handled and length of conveyor systems.
3. Efficient collection of discarded eggs.
4. Frequent adjustment of brushes in washers to minimize breakage.
5. Frequent inspection of egg breaking carrying trays to insure
efficient collection.
6. Collection of shell attached albumen from conveyance system.
7. Eliminate storage vat spillovers.
8. Reduce lengths of product lines.
9. Minimize usage of water in plant clean-up.
10. Efficient removal of egg solids from storage units prior to rinsing.
11. Recovery of egg chalazaes and gelatinous egg solids from the
egg strainer.
12. Recovery of initial flush of blend tanks and pasteurizer.
13. Segregate and recover or dispose on land the overflow and sump
discharge from egg washing.
of the recommendations by Plant A and B did not exceed $300. It was also
judged by the investigators that the recommendations that were adopted
resulted in control of 80 to 90 percent of the waste material that would
be controlled if all 13 recommendations had been used and strictly
enforced.
Effluent samples were collected at Plant A by automatic sampling devices
and also by proportioned composite samples. Internal measurements
included composite samples of the overflow from the breaker, and rinsing
from tanks, pipes and pasteurizer which were impossible to recover. The
waste from the washer was not sampled because it was collected, stored,
and land-filled weekly.
68
-------
In Plant B effluent samples were collected using automatic and composite
samples. Internal measurements consisted of composite samples from the
breaker overflows, washers and the auger drippings (sump). This plant
had made arrangements for land filling its washer water but had not
actually segregated the wastes at the time of sampling, following in-
plant modifications.
While at Plant C composite samples were obtained of the total plant
effluent. Composite samples were taken of the auger overflow, breaker
overflow, washer overflow and sump and the egg grading" washer.
RESULTS OF SAMPLING BEFORE AND AFTER PLANT MODIFICATIONS
Comparison of the in-plant source of organics from common places was not
successful in developing a method of predicting waste loads from various
unit processes. Figure 21 illustrates the difference in waste loads
developed in two washers and three egg breaking machines operating on
the same type of egg quality input and handling the same amount of
product. One washer produced about twice the amount of BODg. All three
of the breakers produced about the same amount of BOD,- per day but the
water usage for one was about half that generated in the other two
breakers.
Tables 9, 10, 11 are results of samples of the total wastewaters taken
at the outfall pipes of three egg breaking plants. The data in these
tables were derived from 6 to 15 composite samples made up of 20 to 30
half hour samples from each day. The wastewater characteristics in
parentheses are values obtained from flow weighted composite samples
whereas the remaining values are results of automatic Sigmamotor samples
composited using time only. Comparison of the values obtained from
these two sampling techniques indicated that the more accurate flow
composited samples were always less than the samples composited accord-
ing to time only. This is expected with highly variable wastes when
69
-------
I
, ,
2500
>
Q 2000
^^
0
UJ
•">
tr 1500
UJ
^
£
Li
o 1000
en
3
< 500
0
100
^_
J '-
1
—
"1
HIGH
^AVERAGE _
f
J!
LOW
_
r''--'-
1
§•!
1
1
•'.-'.
?.
3 •:
— F
".;-;
X""
>"\
!•••!
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^
•:•:
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n
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>;
:-•;
g
;
-'• ;
V.
!••;
ijij
!;I;
•x
:'::'
:•:•:
§:;
••^
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J
WATER BODg
—
-
—
\
E
—
•:•:
•:
•
"-
TV
|t;I
•;:.;
:>"
|
;X
-X
;!;!
:-•_'
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;•"•
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:::::
s
:;::
;X
v:
""»'!
;;:::
"•X-
!•'-'
1
WASHERI
WASHER
BREAKERI
BREAKERU BREAKERIH
FIGURE 21. Waste loads generated from similar egg processing equipment in Plant B.
-------
Table 9 . CHARACTERISTICS OF TOTAL WASTEWATERS
FROM EGG BREAKING FRj)M PLANT A
Result Total
solids
(mg/l )
Initial unannounced
High 9,028a
(5,911)^
Low 4,323
(5,382)
Average 6,676
(5,578)
No. of 12
Determinations (6)
Suspended
solids
(mg/t )
samplings
2,655
(1,751)
860
(1,250)
1,758
(1,414)
6
(4)
Total
Kjeldahl
nitrogen
(mg/t )
737
(628)
378
(462)
558
(518)
6
(3)
Ammonia
nitrogen
(mg/t )
5.9
(6.3)
2.9
(3.3)
4.4
(4.9)
8
(3)
Total
P04-P
(mg/t )
24.4
(59.4)
6.1
(9.8)
15.3
(41.2)
8
(4)
Total
Alkalin
ity as
CaC03
(mg/t )
526
(477)
270
(283)
398
(384)
5
(3)
Before plant modifications
High 10,140
Low 4,907
Average 6,941
No. of 12
Determinations
~ _~
-
-
-
-
-
-
-
-
-
—
-
-
-
-
After in-plant modifications
High 5,744
(2,812)
Low 2,146
(1,396)
Average 3,335
(2.237)
No. of 14
DeterminationOl )
1.385
(833)
425
(180)
803
(519)
16
(13)
461
(240)
210
(84)
298
(178)
16
(13)
7.7
(5.5)
tr.
(tr.)
3.6
(2.9)
12
(9)
22.2
(22.9)
12.7
(6.0)
16.8
(11.8)
14
(12)
456
(366)
208
(264)
348
(312)
9
(6)
Time composited samples
Flow composited samples
71
-------
Table 10. CHARACTERISTICS OF TOTAL WASTEWATERS
FROM EGG BREAKING FROM PLANT B
Result Total
solids
(mgAC)
Initial unannounced
High 4,8473.
(3,622)b
Low 3,792
(3,464)
Average 4,368
(3,557)
No. of 8
Determinations (8)
Suspended
solids
(mg/£)
samplings
1,892
(899)
829
(653)
1,285
(776)
8
(7)
Total
Kjeldahl
nitrogen
(mg/£)
375
(283)
312
(274)
341
(278)
6
(6)
Ammonia
nitrogen
(mg/£)
5.6
(5.7)
4.7
(4.1)
5.2
(5.0)
6
(6)
Total
P04-P
(mg/£)
20.0
(17.1)
16.2
(13.2)
17.9
(15.1)
4
(4)
Total
Alka-
linity
as CaC03
(mg/l)
485
(402)
366
(340)
430
(385)
6
(4)
Before plant modifications
High 6,875
(7,002)
Low 4,138
(4,452)
Average 5,347
(5,449)
No. of 12
Determinations (10)
2,121
(1,253)
370
(330)
1,062
(928)
10
(8)
517
(475)
332
(405)
397
(434)
8
(8)
21.2
(17.9)
2.7
(2.8)
8.1
(8.3)
8
(8)
27.3
(18.5)
8.6
(9.1)
17.9
(13.7)
6
(4)
574
(443)
336
(343)
430
(393)
8
(6)
After in-plant modifications
High 4,411
(5,205)
Low 3,375
(3,177)
Average 4,006
(4,355)
No. of 9
Determinations (11 )
865
(1,037)
231
(190)
539
(643)
16
(18)
338
(430)
243
(232)
295
(311)
8
(8)
2.83
(2.2)
.46
(.8)
1.54
(1.4)
6
(8)
11.6
(12.6)
8.9
(7.8)
10.0
(10.0)
6
(8)
429
(387)
413
(354)
419
(375)
8
(8)
a-r_-
Time composited samples
}Flow composited samples
72
-------
Table 11. CHARACTERISTICS OF TOTAL WASTEWATER
FROM EGG BREAKING FROM PLANT C
Result Total Suspended
solids solids
(mg/e ) (mg/e )
Before plant modifications
No Data Available
After in-plant modifications
High 5,952 1,593
Low 3,727 75
Average 4,514 753
No. of
Determi- 12 12
nations
Total
Kjeldahl
nitrogen
(mg/e)
413
225
302
8
Ammonia Total
nitrogen PO.-P
(mg/e ) (mg/e. )
3.7 55
0 35.9
2.0 42.8
8 8
Total
Alkalin
ity as
CaC03
(mg/e)
1,165
760
1,009
8
73
-------
large and highly contaminated flows occur over short time periods. In
most cases the difference between values obtained using the different
methods was less than 20 percent even for the high and low values. The
difference between the two averages was usually less than 10 percent.
Thus it may be concluded that time composited samples are adequate for
obtaining average concentrations in this industry.
Notable reductions in wastewater pollutant concentrations are indicated
in this data. However, reduction in concentrations does not indicate
the quantity of material actually removed from the wastewaters. The
mass balance data give a much clearer idea of the effectiveness of in-
plant control (Table 12). On the average, 73 percent of organics lost
to the sewer was diverted by in-plant modifications. As can be seen in
Table 12, the bulk of the captured material ended up in animal food.
Thus this demonstrated that a pollution problem was converted into a
salable product.
Tables 13 and 14 show BODg and COD values of the wastewater at Plants A
and B. The oxygen demand of both effluents are reduced by conservation
measures. In plant A, the BOD,- was largely reduced by segregating the
washer water and landfill ing it with the wasted egg shells. In plant
B, the BOD5 was reduced by improved floor management. The washers at
this plant were not segregated and landfilled at the time of post modi-
fication sampling, thus the oxygen demand of the wastewater can be
reduced below the values of Table .14. The overall average ratio of
BOD5/COD for all samples was 0.58. This compares well to the value of
0.66 use as an assumption in the study by Kaufman et al. (22).
Expressing waste loads in Ibs per dozen eggs as opposed to strictly
BODC or COD concentration takes into account the volume of water used
o
in processing and the amount of production. A waste stream could have
a BODg of 3,000 mg/£ before in-plant modifications. This seems to indi-
cate no reduction in waste. However, if the volume of wastewater after
74
-------
Table 12. COMPARISON OF WASTEWATER MASS BALANCES
OBTAINED FOR EGG BREAKING OPERATION IN PLANT A
BEFORE AND AFTER MODIFICATION FOR WASTE CONTROL
Sample Difference between
Day input and output. Fraction
% input ^fillj
and
adherinc
albumen
Before modification
1
2
3
Average
After modification13
1
2
3
Average
-6.8a
-3.5
-5.7
-5.3
-5.2
+3.0
-4.0
-2.0
12.5
12.1
11.9
12.2
12.0
12.5
12.1
12.2
Fate of input,
i of total throughput, %
Animal
food
1
4.2
2.2
3.7
3.4
13.6
4.3
5.7
7.9
Edible
food
76.5
81.6
76.5
78.2
72.5
78.5
81.0
77.3
Loss
to
sewer
7.3
3.7
7.9
6.3
2.3
1.8
1.1
1.7
Negative value indicates calculated more output than input
3Egg washing volume not included after modifications since it
was taken to landfill.
75
-------
Table 13. BIOCHEMICAL AND CHEMICAL OXYGEN DEMANDS
OF TOTAL EGG BREAKING WASTES FROM PLANT A
Result
Initial
High
Low
Average
BOD5
unannounced sampling
7,987a.
(7,106)b
4,350)
(5,887)
6,168
(6,407)
No. of 14
Determinations (16)
Before f
High
Low
Average
)lant modification
11,475
5,267
7,279
No. of 10
Determinations
COD
17,901
(14,349)
5,902
(7,840)
11,902
(10,536) •
6
(14)
14,800
8,964
10,832
6
BODC/COD
0
ratio
.518
(.608)
.672
After in-plant modification
High
Low
Average
No. of
Determinations
6,150
(2,595)
1,132
(589)
2,992
(1,654)
1-f
/
(20)
9,834
(4,390)
2,523
(1,595)
5,005
(3,202)
i n
i y
(22)
.598
(.516)
Time composited samples
3Flow composited samples
76
-------
Table 14. BIOCHEMICAL AND CHEMICAL OXYGEN DEMANDS OF
TOTAL EGG BREAKING WASTES FROM PLANT B
Result BODg
Initial unannounced sampling
High 4,443a.
(3,202)D
Low 3,364
(2,782)
Average 3,961
(2,998)
No. of Determinations 4
Before plant modification
High 6,684
(5,939)
Low 3,054
(3,815)
Average 4,563
(4,661)
No. of Determinations 8
After plant modification
High 3,443
(4,793)
Low 2,949
(2,580)
Average 3,169
(3,661)
No. of Determinations 8
COD
7,084
(5,482)
5,382
(4,884)
6,416
(5,200)
5
11,483
(9,701)
5,821
(6,462)
7,832
(7,759)
20
6,862
(9,051)
4,566
(4,025)
6,050
(6,868)
20
BOD5/COD
ratio
(.576)
.588
(.601)
.524
(.533)
aTime composited samples
Flow composited samples
77
-------
modifications is reduced by 50%, then the Ibs of waste is reduced by 50%
when BOD5 concentrations were equal. The weight of waste alone also is
not a true indicator of losses. A plant could have lost 100 Ibs of BOD
before and after modifications, which again could easily be mistaken as
an indication of no reduction of product losses. If in fact this plant
processed twice as many eggs per day during the post modification period,
then the loss per dozen eggs processed will have been reduced by 50%.
Sewer Losses Per Unit Product
The most meaningful expression to compare product loss to the sewer to
another production facility would be to relate each amount of production
to common pollutants. Unfortunately, the most common unit of production
in the egg industry is the case or dozen. This measure is not as useful
as total weight of production. The weight relationship for eggs varies
from 0.94 Ibs per dozen for small eggs to 1.87 Ibs per dozen for larger
eggs . According to data in Part I of this report, the shell composes
11 percent of the total weight of the egg. Thus the weight of the liquid
portion of eggs varies from 0.84 to 1.66 Ibs per dozen for various sizes.
Industry uses a rule of thumb that 83 percent of the total weight of the
egg ends up as egg product. The data in Table 15 show the relation
between numbers of eggs handled, weight of the eggs, and fraction of the
total weight which became salable product. During four of the five days
the eggs weighed about 1.5 Ibs per dozen and about 1.2 Ibs per dozen
were recovered as processed egg material. This amounted to recovery of
about 80 percent of the total weight of eggs broken in liquid egg product,
or slightly less than the rule of thumb. In the following discussion,
losses expressed on a weight loss per dozen eggs broken will be con-
verted to weight using the average!. 21 Ibs of egg recovered per dozen
eggs broken.
78
-------
Table 15. WEIGHT OF EGGS PROCESSED AND FRACTION OF EGG
MATERIAL RECOVERED IN THE PRODUCT CALCULATED
FROM MASS BALANCE DATA FOR PLANT A
Sample day
Input
Ibs eggs and
shells per dozen
Ib liquid egg
produced per
dozen eggs
broken
Final processed egg
% initial
Before modification
1
2
3
After modification
1
2
1.47
1.52
1.47
1.50
1.73
1.21
1.21
1.18
1.20
1.35
82
80
80
80
78
Tables 16-19 represent volume of water and BOD losses for five various
sized egg processing plants. Plant A has accomplished greater than 50%
reduction in Ibs BOD/dozen. Plant B has similar results even though the
two egg washers in the plant were not segregated from the waste stream
and landfilled. Plant C has accomplished a 75% reduction by improved
floor management without landfilling washer water. Plant D made very
little effort to recover egg product from the inclined auger, egg sniff
tanks and strainers and thus the loss of product is excessively high.
Plant E made sincere efforts to capture auger drippings, residual egg
in tanks and pipes during cleanup, recover strainer solids, and also
scrape egg solids off the floor which had resulted from drippings or
spillover. These efforts are reflected by reduced losses.
The maximum range of water and product loss for all plants was 0.43 to
1.41 gal. per dozen and 0.0048 to 0.0478 Ib BODg per dozen, respectively.
79
-------
Table 16, VOLUME AND WEIGHT OF EGG BREAKING WASTES
GENERATED PER UNIT EGGS PROCESSED IN PLANT A
Production Rate Volume
Result
doz/day gals/day
Wastewater
gals/doz
Weight Egg Lost
BOD5(lb) BOD5(lb)
per doz per lb
liquid ej
Before announced sampling
High
Low
Average
No. of
Determinations
10,260 4,710
9,330 4,010
9,795 4,360
4
.459
.430
.445
.0306 .037
(.0341)a (.041)
.0155 .0188
(.0194) (.024)
.0230 .0278
(.026) (.0314)
18 18
Before plant modifications
High
Low
Average
No. of
Determinations
After in- pi ant
High
Low
Average
No. of
Determinations
9,330 6,133
7,290 4,338
8,385 5,235
4
modifications
8,790 5,846
4,620 3,615
6,945 4,576
6
.711
.500
.627
.952
.452
.689
.0478 .0577
.0261 .0316
.0373 .0451
18 18
.0218 .0204
(.0193) (.0234)
.0048 .0058
(.0077) (.0093)
.0150 .0181
(.01000) (.012)
36 36
aSamples composited according to flow, all others composited according
to time
80
-------
Table 17. VOLUME AND WEIGHT OF EGG BREAKING WASTES
GENERATED PER UNIT EGGS PROCESSED IN PLANT B
Result
Production Rate
doz/day
Volume Wastewater Weight Egg Lost
BOD5(lb) BOD5 (Ib)
per doz per Ib
gals/day gals/doz liquid egg
Before announced sampling
High
Low
Average
No. of
Determinations
18,930
13,080
16,050
3
15,970 1.219 .0414 .050
(.0323)a (.039)
15,050 .844 .0262 .0317
(.0212) (.0256)
15,653 .998 .0329 .0398
(.025) (.0302)
18 18
Before plant modifications
High
Low
Average
No. of
Determinations
After in-plant
High
Low
Average
No. of
Determinations
17,370
15,930
16,680
6
modifications
20,052
10,110
15,719
3
13,990 .878 .0397 .098
(.0371) (.0448)
12,010 .712 .0220 .0266
(.0263) (.0318)
12,825 .770 .0287 .0347
(.0304) (.0368)
34 34
11,220 .768 .0199 .024
(.0203) (.0246)
7,770 .510 .0125 .0151
(.0165) (.2001)
9,737 .646 .0171 .0207
(.0188) (.0228)
18 18
Samples composited according to flow, all others composited according
to time.
81
-------
Table 18. VOLUME AND WEIGHT OF EGG BREAKING WASTES
GENERATED PER UNIT EGGS PROCESSED IN PLANT C
Production Rate Volume Wastewater
Weight egg lost
Result
doz/day
gals/day gals/doz
BOD5 (Ib) BOD5
per doz per lb
liquid egg
Before announced samp! i ng^
After in-plant
High
Low
Average
3,750
modifications
6,330
4,050
5,040
3,597
1,845
1,139
1,382
.959
.319
.209
.274
.0266
.0078
.0051
.0069
.0322
.0095
.0062
.0084
Results taken from one day of sampling in 1972 (2).
82
-------
Table 19. VOLUME AND WEIGHT OF EGG BREAKING WASTES
GENERATED PER UNIT EGGS PROCESSED IN
PLANTS D AND E
Result
Production Rate
doz/day
Volume Wastewater
Weight Egg Lost
gals/day gals/doz
BOD5 (Ib) BOD5(lb)
per doz per Ib
liquid egg
Plant D - Before modifications
High 112,470
Low
Average
No. of
Determinations
Plant E - After
High
Low
Average
No. of
82,800
93,360
2
modifications
70,400
36,000
46,670
2
126,400
103,900
115,000
64,150
37,000
52,800
1,41
1.08
1.23
1.25
1.03
1.13
.0270
.0252
.261
16
.0277
.0163
.0201
16
.0327
.0305
.0316
16
.0335
.0197
.0243
16
Determinations
83
-------
A summary of the average losses is given in Table 20. The measured BODC
o
losses have been converted to liquid egg losses using the average rela-
tionship between BOD and COD (0.58) and COD and whole egg liquid (0.47
ref. 24). For the four plants sampled without modifications for waste
control, 12 percent of the amount of liquid egg processed goes to the
sewer. In other words, more than one egg out of every dozen goes to
the sewer in about 0.9 gallons of water. On the other hand, in plants
where waste conservation and in-plant waste management was utilized, the
average loss was reduced to 6.5 percent of processed product with a low
of 3.1 percent lost. The average water volume generated in modified
facilities was 24 percent less than that in the unmodified facilities.
Figure 22 summarizes the average water and BOD loss measured in all
facilities in this study.
The egg losses are more than those reported in three plants in Holland
(27). See Table 21. The three Dutch plants surveyed include one faci-
lity that had no washing and one that washed both eggs and the plastic
trays in which the eggs were delivered. The water use of 0.49 to 1.56
gallons per dozen eggs was the same as reported here, but the amount of
product lost varied from a low of 0.5 to 4.2 percent of processed egg.
In another survey of plant practices (22) in the U.S. , water losses
from 21 plants and organic losses from 9 plants were estimated by the
plants1 personnel (Table 22). The water use ranged from 0.485 gallons
per dozen eggs processed to 3.27 gallons per dozen eggs with an average
of 1.49 gallons per dozen eggs. The range of wastewater generated agrees
with that found here and the Dutch study. However, the average appears
to be high. It should be noted that some lower waste generation rates
were discarded as being in error in the U.S. study (22).
The product loss reported for the nine plants surveyed in the U.S. study
(22) agrees with the detailed study presented here. The product loss
ranged from a low of 4 percent to 25 percent of processed egg liquid,
84
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Table 20. SUMMARY AVERAGE UNIT PRODUCTION WASTEWATER VOLUME
AND ORGANICS GENERATED IN EGG BREAKING FACILITIES
Plant Plant Plant Plant Plant
A B C D E Avg.
Before modifications
Volume wastewater 0.536 0.884 0.959 1.23 - 0.90
(gal./doz)
Weight egg loss 0.0380 0.0345 0.0322 0.0316 - 0.0341
(BOD5(lb)/lb liquid
eggs)a
(Ib (wt)/lb liquid . 0.14 0.126 0.118 0.116 - 0.125
egg processed)
After modifications
Volume wastewater 0.689 0.646 0.279 - 1.13 0.686
(gal./doz)
Weight egg loss 0.0120 0.0228 0.0084 - 0.0243 0.0169
(BOD5(lb)/lb liquid
eggs)a
(Ib (wt)/lb liquid . 0.044 0.083 0.031 - 0.100 0.064
egg processed)
Calculated by assuming that the weight of liquid egg obtained from one
dozen eggs was 1.21 Ibs.
Calculated as follows:
Ib BOD5 lost lb COD Ib egg liquid _ egg liquid lost
Ib egg liquid processed x 0.58 lb BOD x 0.47 lb COD ~ Ib egg produced
85
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Table 21. WASTEWATER GENERATION INFORMATION FROM THREE EGG BREAKING FACILITIES IN NETHERLANDS "(27)
00
en
Plant Volume Wastewater generated
Plant
A
B
C
activities per, -unit processed
Egg
Wash
yes
yes
no
Egg m water
& 1000 Kg
Tray
Mash
yes 3.8
no 12.0
no 8.0
gal water3
doz
0.49
1.56
1.04
egg
gal water
lb egg
0.45
1.43
0.97
Organics lost to sewer
per .unit processed egg
Kg BOD, lb BOD, 0/ . .a
1000 Kg5 doz 5 * Lost
14 0.015 2.8
21 0.023 4.2
2.4 0.0026 0.5
Calculated using average weight relationships noted in text.
-------
UJ
I-
or
o
h-
<
1.2
0.8
or
UJ —
— 0.4
ui
h-
co
<
BEFORE MODIFICATION-
0.040
CO
UJ
CO c
CO CD
° O
O >H
0.030
0.020
<2
o
03
OL A
o~
0.010
MODIFICATION
1
1
1
1.2
0.8
0.4
1000 2000 3000
(CASES PER DAY)
45,000 90,000 135,000
(TOTAL EGG, Ib per day)
PRODUCTION CAPACITY
,et.al. 1974)
BEFORE MODIFICATION
AFTER MODIFICATION
1
1
0.08
0.04
O
UI
CO
co
UJ
o
O
Q_
O
UJ
.a
co
O
_J
C9
O
LJ
UJ
O
O
or
a.
o
UJ
.a
co
o
o
UJ
CO
1000 2000 3000
(CASES PER DAY)
45,000 90,000 135,000
(TOTAL EGG, Ib per day)
PRODUCTION CAPACITY
FIGURE 22. Summary of the average organic and water volume losses before
and after plant modification for waste control.
87
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Table 22. SURVEY OF WASTEWATER CONTROL AT U.S. EGG PRODUCT PLANTS £2)
Range Average
Volume wastewater (21 plants), 0.4 to 2.7a 1.23
gal per Ib of pasteurized product
Organic waste load, BODC
o
Concentration, mg/1 (9 plants) 1700-6000 3900
IDS per 1000 Ib pasteurized 11-70 33
product (7 plants)
Ibs per day for plant 660
pasteurizing 20,000 Ib egg
aSome values lower than 0.4 were reported by plant manager but discarded
by the authors and not used in the average.
88
-------
and averaged 12.1 percent of the processed material. As was noted earlier
this is the overall average value for product loss as measured in the
four plants sampled during this study that had no modifications for
waste control.
It is interesting to note that the relative magnitude of a waste source
which was not adopted by management in the study was reported by Kaufman
et al. (22). Start and stop losses in a pasteurizer in a 20,000 Ib per
day plant accounted for a product loss amounting to 5 percent of pro-
cessed material, or nearly half the average total losses. Although
recovery or reduction of this waste material may be difficult to achieve
and was not used in this study, emphasis on this possibility would lead
to even more effective waste management than was demonstrated in this
study.
The water usage consumption was reduced mainly by correcting faulty
water valves on the egg breaking machines and placing spray nozzles on
all water hoses. Water usage has been observed to increase with the
size of breaking plants and is due in part to the greater diameter of
water hoses used throughout the larger plants during clean-up.
It is difficult for plant operators to determine the effectiveness of
in-plant management methods because of the difficulty of obtaining
information on the wastewater characteristics. An attempt was made to
relate the major water quality parameters to the simple measurement of
total solids for two plants. The agreement among data points shown
in Figure 23 was almost exactly the same for both facilities supporting
the assumption that the main source of pollution is from egg material.
Thus, the plant operator could obtain approximate concentrations of
pollutants in his effluent by correlating total solids to other parameters.
Another major concept supported by the relationship shown in Figure 23
is that the relative composition does not change after in-plant
89
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BEFORE MODIFICATION
AFTER MODIFICATION
T.S. BOD5 COD TKN NH,-N P04~ P S.S. CQC03
FIGURE 23. Ratio values of average selected wastewater parameter compared
wtth average total solids in Plant A.
90
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modifications are adopted. In other words, the concentrations and total
weight of pollutants may change but this does not greatly increase the
COD and decrease other parameters such as the nitrogen concentrations.
This is an important conclusion in regards to development of treatability
data for wastewater from facilities with and without in-plant management.
It would appear that the treatability results would be applicable to
plants with or without in-plant waste conservation.
91
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SECTION IV
DISCUSSION AND OBSERVATIONS
EFFECTIVENESS OF WASTE MANAGEMENT RECOMMENDATIONS
The following recommendations were suggested to plant operators to help
reduce waste and at the same time increase profits. All of the following
suggestions were not followed by each plant, but enough were adopted to
indicate the anticipatedinpact on waste reduction.
1) Egg shell breakage can result from shipping of improperly stacked
cases. Therefore, it would be advantageous to note the condition of
incoming eggs to inform distributors of mishandling. Some egg producers
may ship excessive numbers of "leakers" which when loaded onto the washer
are broken open and the contents emptied into the wash water. If a plant
operator finds that one of his suppliers is consistently providing an
abnormal amount of "leakers", it would be to the operator's benefit to
try to locate a new distributor as opposed to suffering decreased yields,
increased product loss and increased cost due to pollution control.
2) Egg losses can be reduced by loading eggs directly into egg washers
as opposed to loading eggs onto conveyor belt systems which in turn
carry eggs to the washer. This was adopted by one plant and resulted in
a more efficient production line and apparently decreased egg losses,
but quantitative data were not available.
3) Personnel who load eggs onto the washer oversee the candling opera-
tion and breaking machine operators are expected to remove and discard
inedible eggs, whether they be "leakers," "bloods," or spoiled. A wide
mouthed funnel or inclined trough placed next to each of these personnel,
guide rejected eggs into a receptable without causing floor losses.
4) The vertical motion of the egg washer brushes, particularly when
they are out of adjustment, can penetrate egg shell openings and cause
eggs to be broken. The brushes can be readily readjusted when they are
detected as operating incorrectly. A relationship such as that shown in
92
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Figure 24, relating a quantitative measurement of apparent optical density
to waste concentration,would enable any operator to note malfunctions in
equipment or abnormal egg conditions causing a high rate of soluble egg
to appear in the washer water. A more sophisticated approach would be
to have plants install turbidity detectors.
5) Regular inspections of breaking machines should be carried out to be
sure that trays which catch eggs released from the breaker cups do
retain eggs on the tray; trays are properly overlapped; hoses carrying
product from the breaker to collection vats are securely -fastened; and
the water control valve for the cup sprays is not opened to the point
that water is being used at a rate greater than 7.6£/min (2 gal./min).
6) The usual means of transferring egg shells from the breaker to a
refuse truck was by use of an auger. By tilting the auger at 30° to 45°
the adhering albumen can be separated from the shell and can be collected.
7) Liquid level indicators could be placed in vats which hold egg product
from the breaker, sniff tanks and blend tanks to prevent spillovers. With-
out the use of probes it is up to a plant employee to manually turn pumps
on and off and at the same time perform other duties. The latter tech-
nique is unsatisfactory and has been observed to result in spillovers of
product at least once in every breaking day.
8) Losses of egg product can be reduced by keeping product pipe lines
as short as possible, pitching the pipes so that they drain to the
product's final destination, and eliminating unnecessary equipment such
as blend tanks when egg additives are not used.
9) Plant clean-up operations offer numerous opportunities for product
recovery. During the two major clean-up operations in the egg breaking
day, it is possible to add water to the vat following the breaker and
pump it to the sniff tank. This enables egg to be flushed out of the
product lines. When the product entering the sniff tank is obviously
low in egg solids, the flow is diverted to the floor.
10) The sniff tank is completely drained at each major clean-up period;
however, egg solids will still remain adhered to the tank's sides and
bottom. By tilting the sniff tank on its side, the solids can be
removed with a hand squeegee and pasteurized in future batches.
93
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7,000
5 10 15 20
APPARENT OPTICAL DENSITY SCALE
FIGURE 24. Qualitative relationships between an index of apparent optical
density and the BOD of the egg breaking wastewater.
94
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11) After the egg strainer has been pumped free of egg, the cover is
removed and the screen ft Her is removed. This filter should be placed
into a large shallow container where the chalazae solids can be scraped
off and used as inedible egg product.
12) After all breaking and pasteurization has been completed, the blend
tank or balance tank is filled with water and all empty product lines
are connected. Water is pumped through the pasteurizer and also through
the piping system. Instead of allowing the initial surge of liquid egg
to escape from the end of the pipe system, it is suggested that the
initial discharge be captured in a container, refrigerated and repas-
teurized for by-products. The problem encountered with this technique
of product recovery is determining when to divert the flushings from
the container of liquid egg already salvaged.
13) In smaller plants (1-3 breakers), it is economical to store the
overflow and sump discharge from the egg washer and dispose of it daily
to a sanitary landfill along with the egg shells. By segregating the
wash water from the plants sewer system, the total BOD loading to be
treated is reduced by at least 25%, yet the volume that has to be land-
filled amounts to about 946-1135 liters (250-300 gallons) per washer per
day.
In large plants (10-12 breakers) it may be uneconomical to collect and
land dispose 9460-13626 liters (250-3600 gallons) a day. An alternative
solution might be to try to recover the protein either by drying, chemi-
cal precipitation, or heat treatment.
The potential effectiveness of implementing these recommendations is
shown in Figure 25. As indicated in this figure, the largest portions
of waste can be controlled by management of the egg washer water and
flushes from pipes and pasteurizers. However, the latter is a difficult
recommendation to use and implement. In this study, elimination of the
washer water and closer control over the other smaller losses were
adopted at a low cost of labor and money to the individual egg breakers'
95
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vo
EGG WASHER
SHELL AUGER
DRIPPINGS
MISCELLANEOUS
FLOOR LOSSES
PASTEURIZER STARTINGS
AND STOPS, AND PIPE
FLUSHING
INEDIBLE EGG DISPOSAL
AT CANDLING OPERATION
FIGURE 25. Approximate sources of organic waste loads generated in egg
breaking unit operations.
-------
operations with a resulting 50 percent average decrease in losses. Imple-
mentation of pipe flush control and other good management practice could
probably lower product loss from the 3 or 4 percent loss, considered to be
good for a well managed plant, to nearly 1 percent of the processed product.
It is judged that 1 to 2 percent product loss represents the lower limit
for practical in-plant waste management.
At the present time, eggs that are to be processed are shipped by truck
from grading plants, poultry farms, chicken hatcheries, or retail stores
to the breaking plant. Upon reaching the breaking plants, the eggs are
removed from the cartons and the cartons are recycled to the distributor.
After a number of recyclings the cardboard weakens and will collapse.
Eggs in these types of cartons will become crushed or cracked. Leaking
eggs will usually drain directly to the floor or else they will be
loaded onto the egg washer where the contents are lost to the wash water.
Breakage during shipment can be minimized by not recycling egg cartons
but instead compacting them and selling the cartons as scrap paper.
Until a more durable inexpensive carton material is developed, the
recycling of cartons appears to reduce yields for the egg processors.
Since the major contributor to egg losses in the breaking industry is
the egg washer, it seems logical that larger plants with multiple
breakers could set aside one of its breakers to be preceded by a
washer, to handle "dirties," and the remainder of the breakers could be
operated without washers. Kraft, et al. have shown that commercially
processed whole eggs resulting from both washed and unwashed eggs con-
tain similar bacterial population counts. The same study concluded
that product contamination is instead highly dependent upon sanitation
practices during clean-up operations (28).
Results of bacteriological studies conducted in this study show that
bacteria counts in egg washing liquids increase enormously over the
97
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four hour run periods. In fact, egg washing appears to contaminate egg
surfaces rather than clean them. Data suggest that the washer would
be probably more effective if it was used as an addition in the line
sanitizer area. Experimental results of two 10 day periods at different
locations are included in Appendix B.
By eliminating egg washers, eggs could be placed onto a short rubber
roller conveyor belt. A stainless steel inclined apron to capture any
leaking egg solids would be beneath the conveyor belt and it would guide
them into a container. While on the conveyor belt, eggs would be carried
over a candling operation and then sprayed with a chlorine solution before
being transferred to the breaker.
The advantage of breaking eggs without first washing them is that egg
processors will reduce the amount of egg product lost to the sewer and
at the same time recover an inedible by-product. Assuming that egg
processors lose .04 Ib COD/dozen eggs of which 25% results from washers
o
and 5.83 x 10 dozen eggs are broken annually, it is estimated that 12
million pounds of inedible liquid egg could be recovered by eliminating
washers.
A piece of machinery common to all liquid egg processors is the breaker.
This machine has two major shortcomings. The first is the size of the
stainless steel apron which receives product drippings from the cups
immediately after the egg solids are removed from the cups. When
breakers are operating at 30-40 cases/hour the drippings are thrown
outward as the cups proceed around the machine, but these drippings
could be recovered by simply increasing the size of the steel apron.
The breaker does not have a steel apron on its back side where cups pass
into position to have eggs loaded onto the breaker. After cups pass
through the cup washing portion of the breaker, they turn a corner which
causes egg product to be thrown from the cups. It would be beneficial
at this point to have an apron with elevated sides to collect egg
98
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drippings. This apron could be elevated to drain toward the breaker
operator, with the product emptying into the edible product tray.
Plant E using eight breakers, operates in such a way as to recover
product from tanks, vats, screens and an inclined auger. By conserv-
ing egg solids wherever possible, this plant has managed to make
inedible eggs a profitable by-product. Over 1.5 years of production
data for this plant were analyzed to show that the range of 70-110 Ib
of inedible egg/1000 lls of liquid eggs processed can be captured.
This recovery represents a major fraction of pollution in most faci-
lities. The average inedible product yield of 85.8 lb/1000 Ib of
processed eggs indicates that the egg breaking industry has capabili-
ties of supplying the animal food industry with 60 million Ibs of
liquid egg annually, assuming 700 million Ibs of liquid egg are pro-
cessed annually. Inedible product recovered by conservation measures
combined with the eggs resulting from the elimination of egg washers
constitute a potential 72 million Ibs of inedible egg annually.
Four of the five plants surveyed disposed of empty egg shells by
trucking them to local sanitary landfills on a daily basis. One of
the plants used an incineration system to reduce the moisture content
of the shells from 30 percent to 2 percent (29). The dry product is
more easily handled and stored, with no spoilage during periods when
bad weather prevents disposal. Air drying also collects and retains
the nutrients present in the adhering liquid portion of the shell (30),
and may be an asset when sold to poultry feed producers (31).
Because of the initial capital costs, small breaking plants may not
be able to afford to dry egg shells for use in chicken foods. How-
ever, as noted earlier, the trend for the future is fewer breaking
plants and increased demand of processed liquid eggs. If this con-
solidation of breaking plants occurs, then the profitability of egg
shell drying appears to be more likely for all plants. Assuming 20
99
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million cases of egg at 47 Ibs/case are processed each year, and 11
percent of an egg's weight is shell, the egg breaking industry has capa-
bilities of providing nearly 53,000 tons of dried egg shells annually.
Once management has made in-house modifications to minimize egg product
losses, it is essential that a system be devised to determine daily
product losses. Relationships such as those shown in Figures 23 and 24
must be established between total solids and BOD or COD for each plant
and correlated to egg concentrations in the wastewater. By investing
in a weighing balance, evaporating dishes and a drying oven, and by
knowing the daily flow and wastewater solids concentration, a plant
operator could determine the daily plant losses.
Although egg processing accounts for only 10 percent of the nation's
eggs and grading operations the remainder, the pollution potential of
the processing industry is greater than that of the grading process.
BOD losses from the grading operation of plant C amount to 0.001 Ib
BOD/dozen eggs graded, and work of Hamm et al. (32) indicate that egg
grading losses average 0.0014 Ib BOD/dozen. Results of this study show
that losses ranging from 0.02 to 0.01 Ib BOD/dozen occur in egg breaking
plants after modifications have been implemented. Therefore, egg breakers
handle 10 percent of the country's eggs, but the losses per dozen are
tenfold higher than losses of grading operations.
100
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PART III
EGG BREAKING INDUSTRIAL WASTEWATER
TREATABILITY STUDIES
101
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SECTION I
INTRODUCTION
GENERAL
As part of the increased public environmental awareness, new laws and
regulations are being instituted to control all point sources of
industrial wastes. Included under the Federal Water Pollution Act
Amendments of 1972 are discharges resulting from egg processing
operations. Egg breakers are faced with four options of discharging
their wastewaters in attempting to comply with existing legislation.
First, they may obtain a permit to treat and discharge the wastewater
directly to surface waters. Second, pretreatment may be utilized to
decrease the pollutants to levels of domestic sewage for discharge to
a municipal treatment system. A user charge will be assessed to
industries adopting this alternative. The third option is to discharge
untreated wastes directly to a municipality and pay a user's charge
plus a surcharge which will be related to the egg processor's waste
contribution. Finally, the industry may consider reusing or no direct
discharge by using land application.
Extrapolation of a recent study of wastewater problems in egg breaking
plants (22) indicates that as many as 75 facilities are presently ex-
periencing difficulties in the treatment of their effluents. It might
also be estimated that a large portion of those that are not aware of
the problem will experience difficulties in conforming to new federal
and state regulations in the near future.
A review of the literature has revealed an almost complete lack of
necessary design criteria to enable the design of egg waste treatment
facilities. In order for consultants to advise clients on the treat-
ment scheme which will yield desired results, more detailed treatability
102
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data must be accumulated. The general goals of this portion of the
study were to develop data on the feasibility of control of egg breaking
plant effluents and to determine engineering design criteria that could
be used to design wastewater treatment processes. The alternative situ-
ations under which the feasibility of treatment was determined was the
first three waste treatment alternatives outlined above. The fourth
alternative of effluent reuse or land disposal was not examined. Reuse
of wastewater in the food industry is usually not advisable, and land
discharge of these concentrated wastes would probably require signifi-
cant available acreage.
LOCATION
Treatability studies were conducted on wastewaters from egg breaking
operations in New York State. Samples were obtained from two plants
after first reducing the plants' waste loads through in-plant modifi-
cations. The two plants studied are identified as Plant A and Plant
B in the report.
OBJECTIVES
The background data on the variability and composition of wastewaters
given in Part II indicate that the egg breaking wastewaters will pre-
sent difficult treatment problems. The size of the industry also is a
problem since the largest has a production capacity less than 150,000
dozen per day (about 180,000 Ib/day) and a total design waste flow of
less than 200,000 gallons per day. This flow is equivalent to the vol-
ume of sewage from a community of 2000 people. It is especially diffi-
cult to provide an efficient and inexpensive waste treatment system
for such small but highly contaminated waste flows. Thus the limita-
tions of this portion of the study included development of efficient,
inexpensive and simple waste treatment approaches that could provide
varying levels of treatment. The specific objectives were to:
103
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1, Determine the efficiency of several conventional biological
waste treatment processes tn handling egg breaking wastewaters.
2. Utilize the initial data to develop a series of waste treatment
alternatives that will produce a given removal efficiency at a
minimum cost in terms of capital investment and energy.
3. To develop engineering design criteria for a number of
aerobic and anaerobic treatment processes.
In development of the data in this section it should be noted that
initial emphasis was placed on the use of aerobic systems such as
aerated lagoons and activated sludge because it was felt that dis-
agreeable odors would rule out the use of anaerobic processes. However,
anaerobic lagoons were examined because of their small energy and
maintenance requirements. As will be shown, anaerobic processes were
surprisingly efficient and did not generate the expected unpleasant
odors.
104
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SECTION II
THEORETICAL CONSIDERATIONS
Four types of treatment systems were examined In this study - aerated
lagoons, activated sludge, anaerobic lagoons, and rotating biological
contactors. Inexpensive means of improving the efficiency of treatment
with combination of anaerobic and aerobic lagoons were examined. Also
since the effluent from egg breaking plants was highly biodegradable it
was felt that incorporation of mixing theory by having several small
completely mixed units in series as opposed to one large unit would
be advantageous and this concept was also tested. A summary of the
background theory for the various systems used in this treatability
study follows.
AERATED LAGOONS
An aerated lagoon is a dilute, completely mixed unit operating without
solids recycle. The lagoon is often an earthen basin with elevated
banks to minimize water losses due to wave action caused by aeration
units (33). Oxygen is supplied to the lagoon by either diffused aera-
tors, surface aerators or sparged air turbine systems.
Aerated lagoons have been used successfully in the treatment of a number
of food processing wastes including peas, pear, peach, apple and dairy
(34). This treatment process has experienced widespread use because it
requires little operational control. Biological equilibrium will be
established with time and will adjust automatically to absorb various
changes in loads. The absence of the need for complex mechanical main-
tenance other than lubrication and periodic inspection also makes the
aerated lagoon an attractive treatment process.
The design of a completely mixed aerated lagoon can be based on the
105
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fundamentals of a completely mixed biological reactor. Assuming that
first order substrate removal kinetics and complete mixing exists, the
following equation is obtained from a mass balance of the system (37,38 ):
SQ 1 + Kt (1)
where SQ = the influent soluble substrate concentration (mg/£ COD)
S^ = the effluent soluble substrate concentration (mg/£. COD)
K = the substrate removal coefficient
t = the reactor detention period (days).
By plotting empirical values of SQ/S, for varying values of detention
times a removal coefficient K can be determined from the slope of the line,
CONSECUTIVE COMPLETE MIX REACTORS
Theoretically, plug flow treatment systems are more efficient than
complete mix systems in stabilization of wastes (36). The main disad-
vantage of plug flow systems is their susceptibility to shocks and upsets.
True plug flow systems can be approximated by dividing an aeration basin
into a series of complete mix reactors and still maintain an ability to
withstand shock loads (37). Assuming that all of the reactors in series
are completely mixed and first order substrate removal kinetics apply,
the required volume approaches that required for a true plug flow re-
actor. A system of four reactors in series will theoretically require
43% of the volume required for 85% removal efficiency with one complete
mix reactor. This decrease in required volume becomes more pronounced
as desired treatment efficiency increases. For example, four reactors
in series require 14% of the volume of one reactor for 98% removal ef-
ficiency and would obviously result in decreased capital and operating
costs.
106
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Removal coefficients for reactors in series can be determined by
applying the same theory discussed for aerated lagoons. In this case
the effluent from one reactor becomes the influent of the next and
the removal functions become:
/ = —~U-n (2)
bo (1 + Kt)n
where Sg = the effluent substrate concentration
SQ = the influent substrate concentration
t = the detention time of one reactor
K = the substrate removal coefficient
n = the number of reactors
ROTATING BIOLOGICAL CONTACTOR (RBC)
The rotating biological contactor is in use in Europe and is now being
used in the United States for treatment of certain municipal and
industrial wastes (38,39 ). A number of investigators have documented
the fact that the RBC system has handled shock loads, operated at short
detention times, resulted in low operation and maintenance costs, and
produced a rapidly settling and readily dewatered sludge (40).
Modeling a RBC system requires that substrate and organisms be related
on a mass basis (e.g. Kg COD/Kg microbial solids) (41). Estimates of
the microbial active mass on the rotating discs are difficult to
obtain so an empirical approach has been taken to provide design re-
lationships. The usual means of reporting design criteria is based on
loading rate of organics applied per surface area of disc. By reporting
organic loading as opposed to hydraulic loading, results can be used to
determine the effect of waste streams of variable quality.
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ANAEROBIC LAGOONS
Anaerobic lagoons are earthen basins specifically designed to destruct
and stabilize organic matter. Since mechanical mixing is rarely pro-
vided, anaerobic lagoons act as sedimentation units which may result
in gradual buildup of solids. The rate of solids accumulation is a
function of solids loading, degradability of influent solids and growth
kinetics of the biological population. The rate of solids accumulation
will determine how often solids will have to be removed.
Anaerobic lagoons have been used successfully for treatment of high
strength industrial wastes including canning wastes, meat packing,
paper, textiles and sugar (42). The present design criteria that exist
for anaerobic lagoons are strictly empirical and based on an organic
loading basis (Ib BOD5 or COD/1000 ft /day). Typical values of loading
rates ranged from 4-33 Ib BOD/1000 ft3/day (43).
Due to the high loading rates with anaerobic lagoons, there will un-
doubtedly be significant oxygen demand, solids and nutrients escaping
in the effluent. If the effluent is to be discharged to surface waters,
further polishing will be necessary. Additional treatment can be
attained by use of an oxidation pond or an aerated lagoon. Anaerobic-
aerobic treatment combinations have previously been shown to produce
95% BOD removals for meat packing industry wastewaters (44).
ACTIVATED SLUDGE
The activated sludge process is a complete mix aerobic system followed
by solids separation and recycle. Microbial solids resulting from
gravity separation are partially recycled or wasted. The advantage
of solids recycle is improved effluent quality without increased
reactor volume.
The two common approaches to modeling activated sludge processes are
108
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the food to microorganism ratio (F/M) and solids retention time (SRT)
techniques. Similar design parameters can be obtained from both techni-
ques but the SRT technique is a more rational operation and control
method. The SRT technique is not affected by changes in the feed solids
or influent organic strength, as in the F/M technique. A simple con-
tinuous hydraulic wasting procedure can be used with the SRT technique,
resulting in a more uniformly operated biological system (45).
Lawrence and McCarty have developed a SRT model and have shown that at
steady state conditions the SRT is the inverse of the biological growth
rate (48). The following definitions and equations were developed
in their model.
SRT= M - XV
Ax/At XfW + Xe (Q-W) (3)
U = AS/At M = Q(SQ-S) (4)
lev
= YU - b
dx _ YdS hY
dt ~~dt " bX
where S = the influent soluble substrate (mg/£)
S = the soluble substrate at any time (mg/£)
X = the aeration tank MLSS concentration (mg/£)
X = the recycle suspended solids concentration (mg/£)
X = the clarifier effluent suspended solids concentration
e
109
-------
dx/dt = the net increase in biological solids as a result of
synthesis and endogenous respiration (mg/£-day)
dS/dt - AS/At» the rate of substrate removed per day (Ib/day)
M = biological mass in system (Ib)
Ax/At = the biological mass wasted per day (Ib/day)
U = the specific substrate utilization rate (day" )
Y = the solids yield coefficient (mg cells/nig substrate
removed)
W = the solids volume wasted (gal./day)
V = the volume of aeration tank (gal.)
K = the maximum substrate removal coefficient (day" )
K = the soluble concentration at which the growth rate
is half the maximum rate
the microorganism dei
Q = the flow (gal./day).
b = the microorganism decay coefficient (day" )
Since activated sludge processes require artificial aeration, the oxygen
requirements for the system should be estimated. This can be accom-
plished by assuming oxygen utilization results in substrate oxidation and
endogenous respiration. The following equation results:
^| - .'f+b'X (8)
where d02/dt = the oxygen required (mg/£-day)
a1 = the oxygen required for oxidation of substrate
for energy (mgOp/mg substrate removed)
b1 = the oxygen required for endogenous respiration
(mg Op/mg solids auto-oxidized/day).
It must be remembered that Equations 3 through 8 were developed on
the assumption that the influent waste stream is a soluble substrate.
In practice,wastewaters contain inert influent suspended solids which
110
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will increase the apparent yield coefficient due to absorption of
solids to the active biological floe rather than being oxidized and
utilized for energy and cell synthesis (35). However, if the influent
suspended solids are hydrolyzed in the aeration basin and become
available as substrate the SRT technique becomes valid.
Ill
-------
SECTION nr
MATERIALS AND METHODS
BENCH SCALE APPARATUS AND FEEDING PROCEDURES
Aerated Lagoons
Aerated lagoons were simulated using 75 liter (20 gal.) units at a
2 2
volume of 30 liters with a surface area of 2322 cm (2.5 ft ). Oxygen
was transferred to water by means of three air stones. The system was
seeded with mixed liquor suspended solids from a local activated sludge
sewage treatment plant. During a seven to ten day acclimation period
egg processing wastes were initially applied to the lagoons at rates
well below designed loading rates. The lagoons were fed on a fill and
draw basis, usually once per day, with distilled water added to account
for evaporation losses. Figure 26 shows one of the laboratory models.
Consecutive Complete Mix Reactors _In_ Series
This aerobic treatment process consisted of a 30 liter total liquid
volume unit which was partitioned into 5 compartments. The surface
2 2
area of each compartment was 464 cm (.42 ft ). Mixed liquor from one
cell could only flow to the next cell through a 1.27 cm (.5 in.) hole
drilled in the plexiglass partitions. This unit is shown in Figure 27.
Activated Sludge
The activated sludge system consisted of a 5.5 liter aeration reactor
followed by an 800 ml clarifier. The surface area of the aeration
? 2 2
basin was 251 cm (.27 ft ) and the area of the clarifier was 102 cm
o
(.11 ft ). The effluent from the aeration basin flowed by gravity
112
-------
FIGURE 26. Bench scale model of the aerated lagoon process
FIGURE 27. Baffled aerobic lagoon used to examine the treatability
of egg breaking industrial wastewaters.
113
-------
to a center feed clarifier and overflow from the clarifier was collected
for future analysis (Figure 28).
The aeration basin was seeded with mixed liquor from one of the aerobic
lagoons that was acclimated at an earlier time.
Substrate was pumped continuously over a 16-hour period to the unit
from a nearby cooler maintained at 10°C. By using a time clock to
control the feeding schedule it was possible to simulate the usual
length of time which an egg processing plant produces wastes. The
same pump which transferred feed to the aeration chamber was also used
to recycle sludge from the clarifier to the complete mix reactor.
Solids were wasted from the clarifier in order to maintain a specific
solids retention time (SRT).
Rotating Biological Contactor
Unlike all the other treatment schemes which were operated under labora-
tory conditions, the rotating biological contactor (RBC) was maintained
at the site of Plant B.
The RBC system is made up of 36 polyethylene discs with diameters of
47.3 cm (18 5/8 in.). The liquid volume of the unit is 136 liters
(36 gal.). The effective surface area of the discs is 23.3 m (250 ft ).
The discs were operated at 13 rpm's and were fitted with plastic exten-
sions to help maintain the sloughed solids in suspension (Figure 29).
The RBC module was initially filled with a diluted egg processing waste-
water and seeded with mixed liquor solids from a municipal activated
sludge plant. The RBC system was operated for four days on a fill and
draw basis 37.8 £/day (10 gal./day). Once a light brown growth had
appeared on the discs, the feed to the RBC was applied on a continual
basis for the duration of a processing day, approximately 16 hours. The
114
-------
FIGURE 28. Laboratory scale activated sludge unit used to
examine the treatability of egg breaking
industrial wastewaters.
115
-------
rr,
FIGURE 29. Rotating biological contactor unit used to examine the treatability of
egg breaking industrial wastewaters. (Photographs courtesy of Autotrol Corp.)
-------
wastewater was transferred dtrectly from Plant B's effluent pipeline by
a variable speed pump, to the first cell of the RBC system. A time
clock was installed to feed the RBC at a constant flow rate during the
normal period that eggs were being processed.
The effluent from the RBC was directed to a clarifier with a surface
2 2
area of 582 cm (.626 ft ). The clarified effluent then overflowed
a container which stored the entire treated volume. After a day's
operation the clarified effluent was analyzed and the excess settled
solids were removed from the clarifier to determine excess sludge
production.
Anaerobic-Aerobi c Processes
The anaerobic lagoons were identical in size to the bench scale
aerobic lagoon units. The volume at which the anaerobic lagoons were
operated was 30 t. The aeration basins which followed the anaerobic
lagoons were similar to reactors used in the activated sludge process
and all secondary aerobic units had a detention period of six days.
The anaerobic lagoons were initially filled with tap water and then
seeded with anaerobic solids obtained from a municipal anaerobic di-
gester. Egg processing wastes were added to the anaerobic lagoons
on a fill and draw basis. For the first week of operation the volume
used in the fill and draw procedure was 1 I/day. After the lagoon
seemed to be adapting to the new substrate the volume of feed was
increased to maintain the designed hydraulic retention time (HRT).(See
Figure 30).
The aeration chambers which followed the anaerobic lagoon were seeded
with mixed liquor from the bench scale activated sludge unit and from
a nitrifying population used in the stabilization of poultry wastes.
Effluent from the anaerobic lagoons was supplied to the aeration basins
117
-------
FIGURE 30. Series anaerobic lagoon (20 day SRT) and aerobic
lagoon (6 day SRT) used to examine the treatability
of egg breaking industry wastewaters. (The light
beaker contains the feed substrate and the dark
beaker the SS of the anaerobic lagoon.)
118
-------
on a fill and draw basis. Complete nitrification has been documented
as occurring 1.3 - 2.9 days SRT at 20°C and at approximately 4 days
SRT at 8°C (47,48,49). The SRT value of 6 days used in this study was
chosen to be capable of achieving complete nitrification.
In conjunction with the single cell anaerobic lagoon followed by an
aeration basin another anaerobic treatment scheme was developed. This
system was a five-celled anaerobic lagoon with dimensions identical to
the five chambered aerated lagoon described earlier. The HRT of each
anaerobic cell was 2 days and the volume of each chamber was 6 liters.
This anaerobic system was followed by a 6 liter aeration chamber operated
at a SRT and HRT of 6 days. The dimensions of the aeration chamber were
identical to those used in the single cell anaerobic-aerobic treatment
schemes. Egg processing wastewater was fed to the first cell of the
multi-cell anaerobic system at a nearly constant feed rate over an eight
hour time period.
The effluent from the anaerobic lagoon's last cell was used to feed the
aeration chamber on a fill and draw basis once each day.
SOURCES AND COLLECTION OF EGG BREAKING WASTEWATERS USED IN TREATABILITY
STUDIES
Two egg breaking plants (Plant A and B) located within a twenty mile
radius of Cornell University were chosen as sources of laboratory feed
wastewater. In-plant modifications had been completed prior to use of
the wastewater in treatability studies.
Collection of wastewater samples for treatability studies was obtained
by using an automatic Sigmamotor sampler. Ten equal volume samples
were automatically collected every hour for the entire egg processing
work day. The samples collected throughout the day were automatically
pumped to a plastic sample storage bottle which was stored in an ice-
119
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filled styrofoam cooler. Enough sample was collected in one day to
provide a two day supply of feed for the bench scale treatability
units. The portion of feed not utilized on the first day was stored
at 10°C and then used as a feed for the following day. The bench
scale units were fed for a total of five days per week in an attempt
to simulate the actual egg processing operation.
The wastewater characterization shown in Part II indicated that the
BOD5:N:P weight ratio was less than the optimum 100:5:1 desirable for
aerobic treatment processes. A phosphorus buffer was used to supplement
the feed during the aerobic lagoon and activated sludge studies. How-
ever, no phosphorus was added with the anaerobic processes.
ANALYTICAL PROCEDURES
The egg processing wastes which were fed to the various treatment pro-
cesses and the resulting treated effluent were analyzed for a number
of characteristics. Total solids, total alkalinity, ortho-phosphate
and BODg determination were made in accordance with procedures outlined
in Standard Methods ( 50). Ammonia and Kjeldahl nitrogen were determined
as described by Prakasam et al. (51 ). Both nitrogen analyses are iden-
tical to procedures presented in Standard Methods except for the use of
micro-Kjeldahl digestion and distillation equipment. COD values were
obtained by use of the COD test presented by Jeris ( 52).
Additional analyses performed included suspended solids, by use of a
Millipore filter apparatus and #9-873B (2.4 cm. dia.) Reeves Angel
glass fiber filters. Dissolved oxygen determinations and oxygen uptakes
were determined by a Y.S.I. Model 54 D.O. meter. Effluent turbidity
of certain treatment processes was determined using a Hach Model 2100
turbidimeter.
120
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SECTION IV
RESULTS OF TREATABILITY STUDIES
AERATED LAGOONS
The performance of aerated lagoons is illustrated in Figures 31 and 32
and the data are summarized in Tables 23 and 24. All data are the average
of five or more days of operation during which no change in effluent
characteristics was noted. This steady state condition was obtained in
most tests after 10 or 20 days of unit operation. The lagoons were
maintained at hydraulic retention periods (e) of 10, 20 and 30 days.
All lagoons operated at near neutral pH for the entire steady state
period. The 20 day lagoon fed from wastes of Plant A shows a low pH
of 6.2 and low alkalinity. The loss of alkalinity, low pH and high
nitrate levels indicates an active population of nitrifying organisms
which consumed most of the bicarbonate alkalinity and destroyed still
more buffering capacity through the production of hydrogen ions. The
ammonia nitrogen levels ranged from 0 to 4.6 mg/£ as N, nitrite nitrogen
concentrations from 0.1 to 4.5 mg/£ as N, and nitrate nitrogen in the
range of 24 to 48 mg/£ as N, thus indicating that nitrification
was quite efficient. In full-scale units it may be necessary to
add alkalinity to the lagoon for efficient operation.
Oxygen uptake obtained from the bench scale lagoons showed a definite
decrease in oxygen requirements from 25.3 to 7.0 mg/£/hr as the
hydraulic retention period increased from 10 to 30 days. The aerated
lagoons treating Plant A were capable of reducing a total influent COD
ranging from 4000 to greater than 6000 mg/£ to a soluble effluent COD
less than 700 mg/£ at all three hydraulic retention periods. The
relationship between the total effluent COD produced and the soluble
COD is shown in the unit treating the effluent from Plant B (Figure32 ).
121
-------
6000
4000
2000
30 DAYHRT
— 42 DAYS
- 4000
v.
o>
E
«»
O 2000
o
4000
2000
'NFLUENT TOTAL COD
•EFFLUENT SOLUBLE COD
-30 DAY UNIT DISCONTINUED
I I J I
20 DAY HRT
— INFLUENT AS ABOVE
-EFFLUENT SOLUBLE COD
10 DAY HRT
— INFLUENT AS ABOVE
EFFLUENT SOLUBLE COD
h***fr I I 1 "T
10 20 30 40 50
OPERATION TIME, days
60
FIGURE 3T>. Aerobic lagoon treatment of total egg breaking wastewater
from Plant A at 20°C.
122
-------
HRT= 30 DAYS
INFLUENT TOTAL COD
EFFLUENT TOTAL COD
— /EFFLUENT SOLUBLE COD
»J
HRT = 20 DAYS
r 9000
INFLUENT TOTAL COD
Q 5000
O
0 2000
EFFLUENT TOTAL COD
EFFLUENT SOLUBLE COD
HRT= 10 DAYS
INFLUENT AS ABOVE
EFFLUENT TOTAL COD
^EFFLUENT SOLUBLE COD
10 15 20 25
OPERATION TIME, days
FIGURE 32. Aerobic lagoon treatment of total egg breaking wastewater
from Plant B at 20°C.
123
-------
With an influent total COD ranging from 5000 to 10,000 mg/£, the soluble
effluent was consistently less than 1000 mg/£, with the total COD about
double the soluble COD. Even though these results indicate that aerated
lagoons are capable of soluble COD removal efficiencies greater than
90 percent, the quality of effluent is not good enough to satisfy effluent
discharge requirements. The units also had a sharp pungent odor for
aerobic treatment processes.
Table 23. SUMMARY AERATED LAGOON CHARACTERISTICS
AND REMOVAL EFFICIENCIES
Lagoon Characteristics
Plant A Plant B
Hydraulic retention period, days
Parameter 10 20 30 10 20 30
SS (mg/£)
Oxygen uptake rate
Removal efficiency
COD, total
COD, soluble
TKN, total
1,050
(mgAC/hr) -
(%)
59.8
89.7
64.2
560
9.3
72.3
88.3
41.2
550
7.3
81.1
96.2
64.9
890
25.3
69.2
86.9
51.1
1,300
13.8
66.1
93.7
49.8
850
7.0
76.5
94.3
58.7
Effluent total TKN values show that removals of organic nitrogen range
from 41% to 64% depending on the hydraulic retention time.
Throughout the study period it was noted that when the effluent from
any one of the aerated lagoons was allowed to settle in a 1000 ml
cylinder the percentage of suspended solids actually settling to the
base of the cylinder was minimal. The biological floes formed in these
124
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Table 24. AERATED LAGOON INFLUENT AND EFFLUENT CHARACTERISTICS TREATING WASTEWATER
FROM PLANT A AND B. LAGOON TEMPERATURE 20°C. (All units in mg/£
unless otherwise noted, mean values; 5 < n < 10.)
Parameter
COD, total
COD, soluble
TKN, total
PH
Alkalinity
as CaC03
NH3-N
N02~N
N03-N
INFLUENT WASTEWATER
Plant A
Plant B
Hydraulic detention period, days
10 20 30
4980 4980 5130
_
201 201 234
_
_
_
_
_
10 20 30
6300 6300 5850
_
295 295 298
_
_
_
-
_
TREATED EFFLUENT
Plant A | Plant B
Hydraulic detention period, days
10 20 30
2000a 1380a 970
509 581 191
72 118 82
7.2 6.2 7.1
71 29 68
0 4.6 0
0.1 4.5 1.0
4.3 46.0 28.3
10 20 30
1940 2140 1370
825 390 333
144 148 123
7.3 7.0 7.4
157 105 127
1.0 0.4 1.2
1.1 1.2 0.5
24.5 43.5 47.4
no
01
estimated from weight:COD relationships
-------
systems were dispersed in nature and did not resemble floe formations
of typical municipal treatment systems. The SS of the effluent varied
from 560 to 1,300 mg/£ and imparted a highly turbid yellow appearance
to the effluent.
The ratio of influent total COD (SQ) to effluent soluble COD (S,)
was plotted against HRT of the aerated lagoons in order to determine
the substrate removal coefficient (Figure 33). The removal coefficients
(K) were 0.76 day" and 0.58 day" for Plants A and B, respectively.
CONSECUTIVE COMPLETELY MIXED REACTORS
A second aerobic treatment process investigated was a system of completely
mixed reactors in series. It was of interest to determine treatment
efficiency of a simulated plug flow system and compare the results to
those obtained by a single cell lagoon of an equal overall HRT at the
same temperature.
Results of the 5 cell aerated system are outlined in Table 25. Effluent
quality expressed as total COD and soluble COD from this multiple cell
treatment system is illustrated in Figure 34. There was not a substan-
tial decrease in pH throughout the reactors in series but there was
evidence of alkalinity reduction due to the nitrification. Nitrate
concentrations of 22 mg/£ are similar to nitrate values experienced in
a single cell aerated lagoon (24.5 mg/£ N03~N) and thus indicate similar
efficiencies of nitrification between single cell vs. multi-cell treat-
ment. It is impressive to note that retention of the wastewater for 10
days in the 5 cell unit produced removal efficiencies equal or greater
than those obtained at a retention period of 30 days in a one cell unit.
In comparing overall removal efficiencies of the 5-cell system to those
of a single cell lagoon of an equal or larger detention time (Table 23)
it becomes evident that consecutive complete-mix reactors do in fact
increase COD and TKN removals.
126
-------
40
UJ
ID
UJ
30
t-
z
UJ 20
u.
UJ
10
FEED SOURCE - PLANT A
K= 0.76 DAV1
LEAST SQUARE FIT, r= 0.90
Q
O
O
e
i-
UJ
ID
o
o
o
UJ 20
-I
CD
h-
UJ
u.
u.
UJ
10
FEED SOURCE-PL ANT B
K= 0.582 DAY'1
LEAST SQUARE FIT, r = 0.97
10 20
HRT.doys
30
40
FIGURE 33. Determination of substrate removal coefficients for aerated
lagoons treating wastewaters from Plants A and B at 20°C.
127
-------
7000 —
6000
5000
4000
E
M
Q
O
FEED FROM PLANT B
• INFLUENT TOTAL COD
EFFLUENT TOTAL COD
EFFLUENT SOLUBLE COD
3000 —
2000 —
1000 —
20 30 40 50
OPERATION TIME, days
70
FIGURE 34. Aerated lagoon treatment composed of 5 cells connected
in series with a hydraulic detention period of 2 days
each at 20°C.
128
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Table 25. CHARACTERISTICS OF 5-CELL AERATED LAGOON OPERATED AT
20°C WITH A TOTAL LIQUID RETENTION PERIOD OF TEN DAYS
(2 DAYS IN EACH CELL) (All quantities in mg/£ unless
otherwise noted, mean values 5 < n < 25)
Parameter Influent
COD, total 4490
COD, soluble
TKN, total 236
SS
pH
Alkalinity, as CaC03
Oxygen uptake,
mg Op/£/hr
NH3-N
NO^-N
NO'-N
Turbdity
Removal Eff., %
(Accumulative)
COD, total
COD, soluble
TKN, total
1
3600
280
271
2910
7.5
266
27.6
9.1
-
19.8
93.8
-
Cell no.
3
2040
220
155
1610
7.4
218
15.0
4.2
-
54.7
95.1
34.3
5
675
180
58
380
7.4
176
4.8
1.7
0.5
22
99
84.9
95.9
75.4
129
-------
Table 26 shows a comparison of removal efficiencies in various aerobic
lagoons.
Table 26. COMPARISON OF ONE COMPLETELY MIXED UNIT AND MULTI-
CELL AEROBIC LAGOON TREATMENT OF EGG BREAKING WASTES
Aerobic system
@ 20° C
Process Efficiency of Removal, %
Total COD Soluble COD Total TKN
5-cell 10 day
aerated lagoon
Single cell 10 day
aerated lagoon
Single cell 30 day
aerated lagoon
84.9
59.8-69.2
76.5-81.1
95.9
86.9-89.7
94.3-96.2
75.4
51.1-64.2
58.7-64.9
It was of value to note the high effluent turbidity of the 5-cell aerated
system of 99 JTU's. The poor settleability of the suspended solids and
a residual yellow color which was also prevalent in effluents of single
cell aerated lagoons may very well prevent the use of multi-cell aeration
systems in the production of wastewater effluents for direct discharge
to surface waters. However, this unit would appear to be a good alter-
native for pretreatment in preparation for further joint treatment.
ACTIVATED SLUDGE
It was anticipated that treatment of egg breaking wastewaters with the
activated sludge process would be difficult because of the high strength
of the wastes. In order to achieve an acceptable organic mass loading
it was necessary to maintain the hydraulic detention period (HRT)
longer than four days. The data shown in Figures 35 and 36 indicate
130
-------
INFLUENT TOTAL COD
EFFLUENT TOTAL COD
EFFLUENT SOLUBL'E COD
6000
O>
E
a"
O
o
4000
2000
12 16 20 24
OPERATION TIME, days
FIGURE 35. Activated sludge treatment of wastewaters from Plant B at 20°C,
HRT = 4 days, SRT = 4 days.
-------
5000
4000
o»
E
3000
CO
O
o
<-> 2000
1000
• INFLUENT TOTAL COD
• EFFLUENT SOLUBLE COO
A EFFLUENT TOTAL COD
8
12 16 20 24
OPERATION TIME, days
28
FIGURE 36. Activated sludge treatment of wastewaters from Plant B at 20°C,
HRT = 4 days, SRT = 10 days.
-------
that the effluent quality was similar to the effluent from the aerated
lagoons.
Table 27 summarizes all results from activated sludge treatment of
wastes from Plants A and B. Table 27 shows that pH values were observed
to be in a range of 7.0-7.6 and alkalinity was not limiting the conver-
sion of ammonia nitrogen to nitrate nitrogen. Nitrate concentrations
of 32.8 mg/£ were experienced at an SRT of four days in one instance
and approximately 2 mg/£ at an SRT of 4 days using wastes from Plant A.
This seems to indicate that an SRT of 4 days may be the lower limit at
which efficient nitrification occurs.
The sludge in these units settled poorly and the high effluent turbidities
indicated that this process would be a poor choice for the treatment
of egg breaking wastes.
Data accumulated from the bench scale operations were arranged in such
a manner as to produce yield, endogenous respiration and oxygen utili-
zation coefficients. Yield coefficients were 0.245 and 0.300 mg cells
per mg COD removed (soluble COD basis), endogenous respiration coeffi-
cients were determined to be 0.060 and 0.043 day~ , and oxygen use
coefficients were 0.583 for a1 and 0.164 day" for b1.
The activated sludge process is capable of producing an effluent suitable
for discharge to a joint treatment system without resulting in a sur-
charge for excessive oxygen demand or suspended solids. However, problems
with settleability of the sludge should be anticipated with this system.
ROTATING BIOLOGICAL CONTACTOR
A final aerobic treatment process investigated was the rotating bio-
logical contactor (RBC). All of the previous treatment schemes involved
133
-------
Table 27. CHARACTERISTICS OF ACTIVATED SLUDGE TREATMENT OF EGG
PROCESSING WASTEWATEKS AT 20*C (All quantities in nig/*
unless otherwise noted, mean Value, 5 < n < 35)
SRT, 6c (days)
Parameter HRT, e (days)
Influent cone.
COD, total
TKN, total
Operating conditions
PH
Alkalinity, as CaC03
02 uptake, mg 02/^/hr
NH3-N
NO>N
N05-N
Clarified treated effluent
SS
COD, total
COD, soluble
TKN, total
Turbidity, JTU
Removal eff., %
COD, total
COD, soluble
TKN, total
Plant A
10 4
4 4
5,130 4840
234 198
7.0 7.3
46 152
18.4 -
3.1 18.8
5.5 16.4
20.2 1.9
158
325
101 914
27
-
94
98 81
88
10
4
5970
277
7.
200
18.
21.
0.
51
496
1140
401
105
190
81
93
62
Plant B
7
4
4450
197
2 7.6
183
0 7.2
8 12.9
4 0.2
14
149
344
140
46
78
92
96
76
4
4
5170
258
7.4
198
20.1
20.3
2.3
32.8
380
1140
441
69
102
78
91
73
134
-------
suspended growth systems whereas the RBC is an adhered growth treat-
ment unit. This system is similar to the previous processes in that
excess solids are produced by the oxidation of the substrate and have
to be removed from the effluent.
Figure 37 contains the results from RBC treatment at a hydraulic reten-
tion period of nearly two days and Table 28 summarizes the results
obtained with this process. The pH of the effluent varied from 7.2-7.7
without any deficits in total alkalinity. A surprising result was that
nitrification was at least 50 percent efficient at high loading rates
even though the effluent COD exceeded several hundred mg/£. Regardless
of the loading rates used (1.4-7.3 Ib COD/1000 ft ) there was always a
dissolved oxygen level in all of the four RBC cells.
The RBC units are capable of producing effluents suitable for further
treatment without surcharge payments to minicipalities and at low
loadings can produce effluents with turbidities less than 27 JTU. Pre-
treatment using RBC units can be accomplished at low loading rates,
2
< 3 Ib COD/1000 ft -day. The question that must be answered for a
particular egg processing plant is whether the capital cost for equip-
ment and operating costs for power, maintenance and sludge handling are
less than surcharges encountered if no treatment was applied.
ANAEROBIC-AEROBIC SERIES TREATMENT
When it was observed that the activated sludge process and aerated
lagoons were continuously producing effluent with high turbidity,
dispersed biological floes and residual color, additional alternatives
needed to be developed in order to provide higher quality effluents.
The thought of operating an anaerobic process initially brought to mind
production of obnoxious odors, namely hydrogen sulfide or "rotten egg"
odors. Contrary to this assumption, anaerobic lagoons operated in this
study did not produce highly objectionable odors. However,
135
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5000
4000
3000
O
O
O
2000
1000
FEED RATE = 20 gal/day ,80gol / 1000ft ,
or 3.13 Ib COD/1000ft2
• TOTAL INFLUENT COD
• SOLUBLE INFLUENT COD
* TOTAL EFFLUENT COD
A SOLUBLE EFFLUENT COD
I I I I I I
68 10 12 14
OPERATION TIME , days
FIGURE 37. RBC treatment characteristics with wastewaters from Plant B.
136
-------
Table 28. ROTATING BIOLOGICAL CONTACTOR TREATMENT CHARACTERISTICS
WHEN APPLIED TO EGG BREAKING WASTES FROM PLANT B
(Operating temperatures were 21 to 24°C - all units in
mg/£ unless otherwise noted, mean value 5
-------
anaerobic lagoons by themselves would not be acceptable because of the
oxygen demand associated with the discharge of wastes from anaerobic
processes. Thus all anaerobic lagoons were followed in series with
aerobic lagoons operating at a six day detention period. Another con-
cern with the anaerobic processes was that low temperatures would cause
depressed removal efficiencies. Thus comparative studies were conducted
at 20°C and 10°C.
A total of six anaerobic lagoons followed by aeration chambers were
examined. Four of the lagoons were operated at 20°C and two at 10°C in
order to determine temperature effect on removals and solids accumulation.
The data illustrated in Figures 38, 39 and 40 are representative of the
surprising capabilities of this combination system. Data for all units
are summarized in Table 29. All soluble COD removal efficiencies
exceeded 98 percent and system number 6 (Table 29) with a 5-cell anaer-
obic unit was most efficient. A 5-cell anaerobic lagoon and a 1-cell
anaerobic lagoon both operated at 20°C and a HRT of 10 days resulted in
similar reductions in TKN, but the total COD removal in the 5-cell anaer-
obic lagoon was 91.4% and the single cell system was 81.7% efficient.
Similar graphical analysis for substrate removal coefficient, K, was
conducted for the anaerobic lagoons as for the aerobic lagoons shown
in Figure 24. The 20°C anaerobic lagoon K was found to be 0.63 day" .
This was very similar to the removal coefficients obtained for the aero-
bic lagoon treatment of wastes from Plants A and B (0.76 and 0.58 day" ,
respectively). This procedure was not applicable to the lower tempera-
ture anaerobic lagoons and the aerated lagoons because the lack of
difference between the characteristics of the units studied. However,
the observed efficiencies at 10 and 20 day hydraulic retention periods
at 10°C were similar to that observed at 20°C even though the effluent
was 50 percent less at this higher temperature. Whereas the 20°C ten
day HRT anaerobic lagoon removed 82 percent of the total COD, the
removal efficiency in the same lagoon at 10°C was 77 percent efficient.
138
-------
10,000
5,000
o>
E
Q
O
O
1,000
500
too
50
10
ANAEROBIC LAGOON, INFLUENT TOTAL COD
5DAYHRT, 20°C
ANAEROBIC LAGOON, EFFLUENT TOTAL COD
AEROBIC LAGOON,INFLUENT TOTAL COD
6 DAY HRT,20°C
AEROBIC LAGOON,EFFLUENT TOTAL COD
AEROBIC LAGOON, EFFLUENT SOLUBLE COD
I I i ' i i i i i i i i i i
3 4 5 6 7 8 9 10 II 12 13 14
OPERATION TIME.doys
FIGURE 38. Series lagoon treatment with 5 day HRT in the first anaerobic
lagoon at 20°C and 6 day HRT in the aerobic lagoon at 20°C.
139
-------
6000
4000
2000
«^»
s.
o»
6 1000
800
0
o
o
10
o
o
00
600
400
200
100
80
60
40
20
10
10
INFLUENT TOTAL COD
EFFLUENT TOTAL COD
OF ANAEROBIC LAGOON
EFFLUENT TOTAL COD OF
AERATED LAGOON
EFFLUENT SOLUBLE COD
OF AERATED LAGOON
EFFLUENT TOTAL BOD
OF AERATED LAGOON
I
ANAEROBIC LAGOON HRT = 10 DAYS
AERATED LAGOON HRT = 6 DAYS
TEMPERATURE = 10 °C
I
20 30 40 50
OPERATION TIME , days
60
FIGURE 39. Series lagoon treatment with 10 day HRT at 10°C in the first
anaerobic lagoon and 6 day HRT at 10°C in the aerobic lagoon.
140
-------
10,000
5000
1000
500
o>
E
o
u
in
Q
O
CD
100
50
10
5
2
o ANAEROBIC LAGOON, INFLUENT TOTAL COD
HRT= 20 DAYS , 20°C
A ANAEROBIC LAGOON,EFFLUENT TOTAL COD
A AEROBIC LAGOON, EFFLUENT TOTAL COD
HRT = 6 DAYS,20°C
• AEROBIC LAGOON, EFFLUENT SOLUBLE COD
• AEROBIC LAGOON, EFFLUENT SOLUBLE BODg
I 1 I I I I I I I I
10 20 30 40 50 60
OPERATION TIME,days
70
FIGURE 40. Series lagoon treatment with 20 day HRT at 20°C in the first
anaerobic lagoon and 6 day HRT at 20°C in the aerobic lagoon.
141
-------
Table 29. TREATMENT OF EGG BREAKING WASTEWATERS USING SERIES TREATMENT OF ANAEROBIC LAGOONS
FOLLOWED BY AEROBIC LAGOONS (All aerobic lagoons have an HRT of 6 days - all
quantities in mg/£ unless otherwise noted, mean value 5 < n < 31)
Parameters
Temperature, °C
HRT, days
Influent COD, total
Effluent COD,
total
soluble
Organic loading rate,
Ib COD/ 1000 ft2-day
Effluent turbidity, JTU
Soluble COD removal efficiency, %
unit
system
Influent TKN, total
Effluent TKN, total
TKN removal efficiency, %
unit
system
System 1
Anaerobic - Aerobic
20
20
7020
590
22
-
91.6
9
328
165
6
590
90
_
4.8
84.7
8.7
165
35
42 79
89.3
System 2
Anaerobic - Aerobic
10
20
4200
944
13
-
77.5
98
221
164
26
52
6
940
66
.
9.1
93.0
.4
164
105
36
.5
System 3
Anaerobic - Aerobic
20
10
4900
896
31
_
6
896
72
_
81.7 ' 92.0
98.5
230
187
19
8
187
38
80
3.5
-£»
ro
-------
Table 29. TREATMENT OF EGG BREAKING WASTEWATERS SERIES TREATMENT OF ANAEROBIC LAGOONS
(continued) FOLLOWED BY AEROBIC LAGOONS (All aerobic lagoons have an HRT of 6 days - all
quantities in mg/£ unless otherwise noted, mean value 5 < n < 31)
Parameters
Temperature, °C
HRT, days
Influent COD, total
Effluent COD,
total
soluble
Organic loading rate
Ib COD/1000 ftz-day
Effluent turbidity, JTU
Soluble COD removal efficiency, %
unit
system
Influent TKN, total
Effluent TKN, total
TKN removal efficiency, %
unit
system
System 4
Anaerobic - Aerobic
10
10
4530
1050
29
-
6
1050
86
mf
21.4
77.1 91.8
98.1
209
157
25
2<
157
147
6.4
3.7
.1
System 5
Anaerobic - Aerobic
20
5
5430
1970
68
-
63.7
9!
287
267
8.7
81
6
1970
72
mm
-
96.3
3.7
267
58
78
3.0
System 6
Anaerobic - Aerobic
(5 cells)
20
10
4600
395
29
-
91.4
9!
220
183
16.8
9
6
395
48
— t
5.8
87.8
3.9
183
70
96.2
5.8
-------
Thus it can be concluded that there was little effect on the substrate
removal coefficient between 10°C and 20°C. The greatest difference
occurred in the loss of nitrification activity at 10°C.
Perhaps the most impressive characteristics of the combination
anaerobic-aerobic lagoon system was the high clarity and highly floc-
culated nature of suspended materials in the effluent from the aerated
unit. In no case did the total effluent turbidity exceed 10 JTU for
units operated at 20°C and 10°C. Since all solids settled rapidly the
soluble BODg values shown in Figure 40 of about 10 mg/t are indicative
of the efficiency that this treatment combination is capable of
achieving with an influent COD varying between 5,000 and 10,000 mg/£
and a total system hydraulic detention period of 26 days.
Detailed summary of influent and effluent characteristics for single-
cell series lagoon systems are given in Tables 30 and 31.
MULTI-CELL VERSUS SINGLE CELL SYSTEMS
Egg wastewaters are highly biodegradable and for this reason can be
treated by various combinations of systems. Utilization of multi-cell
units enable the use of smaller systems to achieve the same treatment
efficiency. Data supporting this statement are illustrated in Figure 41
Total COD removal with a one-cell aerated lagoon at ten day HRT
achieved 60 percent removal efficiency, whereas a five-cell aerobic
lagoon with the same overall HRT achieved a removal efficiency of 83.5
percent, and a five-cell anaerobic unit with a ten day HRT obtained
a removal efficiency of 91 percent. The soluble COD removal efficiency
in a five-cell unit aerobic lagoon with a system HRT of six days was
equivalent to that obtained in a one-cell unit at about thirty days HRT.
Thus these data indicate that compartmentiTization of lagoons treating
egg breaking wastes will improve the efficiency for any given volume.
However, to protect the system against shock loads it is suggested
that no more than three cells be used for any lagoon.
144
-------
Table 30. INFLUENT AND EFFLUENT CHARACTERISTICS OF SINGLE CELL ANAEROBIC LAGOONS FOLLOWED BY
AEROBIC LAGOONS WITH HRT OF 6 DAYS AT 20°C (All units in mg/£ unless otherwise noted ,
mean value 5 < n < 31)
Parameter
COD total
COD soluble
BOD total
BOD soluble
Suspended
solids
PH
Total alkalin-
ity as CaC03
TKN
NH3-N
N02-N
N03-N
Qy uptake
Turbidity JTU
after 2 hours
settling
Influent
HRT, days
5 10 20
4300 4900 2020
-
-
-
- - _
-
— — _
290 230 320
-
- -
- -
-
-
Effluent
HRT, days
5 10 20
1970 900 590
- -
-
-
— — _
6.9 7.1 7.2
135 810 720
260 190 164
230 158 136
_
_
-
_ _ _
Effluent
following
5
680
72
-
-
4.5
7.2
75
58
0.1
6.25
108.3
18.0
_
from aerobic lagoons
anaerobic
HRT, days
10
410
72
-
-
320
7.0
60
38
25
15.6
109.3
10.3
—
lagoons with
20
300
90
370
13
220
7.3
160
35
21
22.0
91.9
5.2
4.8
01
-------
Table 31. INFLUENT AND EFFLUENT CHARACTERISTICS OF SINGLE CELL ANAEROBIC LAGOONS FOLLOWED BY
AEROBIC LAGOONS WITH HRT OF 6 DAYS AT .10°C (All units in mg/l unless otherwise noted,
average value 6 < n < 15)
Parameter
COD total
COD soluble
BOD total
BOD soluble
Suspended
solids
PH
Alkalinity
as CaC03
TKN
NH3-N
N02-N
N03-N
Op uptake
Turbidity JTU
after 2 hours
settling
Influent
HRT, days
10 20
4580 4200
2400 2500
-
-
730 670
-
208 221
-
Effluent
HRT, days
10 20
1050 944
' -
470
-
-
7.5 7.4
620 662
157 164
105 133
Effluent
following
10
574
86
-
-
355
8.6
553
147
78.1
0.1
0.2
7.0
21.4
from aerobic lagoons
anaerobic lagoons with
HRT, days
20
585
66
220
29
308
7.7
222
104
37.9
1.5
49.8
6.9
9.1
at
-------
100
90
80
- 70
>
o
2
UJ
O 60
u_
LJ
<
>
O
50
ui 40
a:
30
20 —
10
ANAEROBICC5CELL)
TOTAL COD
SOLUBLE COD
I
I
AERATED
AEROBIC
(5 CELL)
I
10 20 30
HYDRAULIC RETENTION PERIOD.days
FIGURE 41. Comparison of multi-cell and single cell aerobic and anaerobic
treatment processes at 20°C.
147
-------
Detailed summary of analysis for the multiple cell anaerobic-aerobic
system is shown in Table 32. All values in this table are averages
of six days of steady state operation.
LAGOON SLUDGE ACCUMULATION
Most lagoon treatment systems do not have sludge collection or handling
components. However, operation of these units on egg breaking waste-
water raised several questions. The high clarity and low solids
concentrations in effluents of the system indicated that most of the
solids entering the system were biodegradable. Although all units
were completely mixed at least once daily, the wasting procedure with
the anaerobic lagoons was conducted before mixing in order to more
closely approximate actual field conditions. Wasting took place from
a submerged tube midway between the floating scum layer and the sludge
on the bottom. It also appeared that the egg wastes and the anaerobic
system acted as an efficient bio-precipitation unit. Thus, it was
important to estimate the rate of sludge accumulation that might occur.
Also, because of the rapid settling nature of the SS in the effluent
from the secondary aerobic lagoon it was felt a liquid solids separation
step would clarify the effluent.
A typical rate of accumulation of solids in anaerobic lagoons is shown
in Figure 42. This data indicates that the rate of solids accumulation
in the first unit of the series treatment system is small at tempera-
tures of 20°C, but increases significantly at lower temperatures.
Further studies are needed to determine the net yield over long periods
when the temperature varies significantly. Data for all anaerobic
lagoons is summarized in Table 33. It is interesting to note that the
longer the retention period and the higher the temperature, the lower
the sludge accumulation rate. Long term storage of sludge in this unit
at temperatures around 20°C would probably result in a low rate of
sludge accumulation.
148
-------
Table 32. INFLUENT AND EFFLUENT CHARACTERISTICS OF A 5-CELL
2 DAY HRT PER CELL ANAEROBIC LAGOON FOLLOWED BY AN
AEROBIC LAGOON WITH A 6 DAY HRT AT 20°C (average
value 10 < n < 15)
COD, total
COD, soluble
Suspended solids
pH
Total alkalinity,
CaC03
TKN (mg/l)
NH3-N (mg/t)
NO~-N (mg/l)
NO~-N (mg/t)
02 uptake (mg/£/hr)
Turbidity (JTU)
Influent to
5-cell
Anaerobic Lagoon
4604
2725
721
-
-
220
-
-
-
-
_
Effluent from
5-cell anaerobic
lagoon & influent
to aeration chamber
395
120
-
7.9
885
183
153
-
-
-
_
Effluent from
aeration chamber
following an-
aerobic lagoon
177
48.2
177
6.5
37
7.0
4.1
6.0
133
8.9
5.8
149
-------
10.0 —
LOST IN EFFLUENT
STABILIZED
ACCUMULATED
10
HRT, days
TOTAL SOLIDS ADDED
NET SOLIDS ADDED
• MEASURED SOLIDS IN
THE LAGOON
LOST IN EFFLUENT
STABILIZED
I
ACCUMULATED
10 20
HRT, days
FIGURE 42. Comparison of the fate of solids in anaerobic lagoons
with 10 day HRT at 20°C (top) and 10°C (bottom).
150
-------
The sludge accumulation is less in the aerobic lagoon than in the an-
aerobic process. The measured volume of sludge that accumulates is
shown in Table 34, expressed as a fraction of the total volume of
wastewaters treated. The accumulation rate was about 2 percent of the
flow in most instances.
Table 33. MEASURED SLUDGE SOLIDS ACCUMULATION RATE IN ANAEROBIC LAGOONS
Anaerobic lagoon operating conditions Solids accumulation rate
HRT (days) Temp (°C) % of total solids added per day
10
20
5
10
20
10
10
20
20
20
30
68
12
6.0
5.4
Table 34. MEASURED SLUDGE VOLUME ACCUMULATION RATE IN EFFLUENTS FROM
6 DAY HRT AEROBIC LAGOONS FOLLOWING ANAEROBIC LAGOONS
Pretreatment Sludge volume
anaerobic lagoons aerobic lagoon accumulated
HRT (days) Temp (°C) Temp (°C) (% total volume treated)
10
20
20
10 (5-cell)
10
10
20
20
10
10
20
20
1.7
3.7
2.7
1.2
151
-------
Although the sludge accumulation data shown in Tables 33 and 34 are
highly empirical they serve to indicate the relative magnitude of sludge
storage volume required. Further studies need to be conducted to eval-
uate the design parameters for liquid-solids separation and sludge
disposal systems.
152
-------
SECTION V
DISCUSSION
This treatability study encompassed a variety of aerobic and combina-
tion anaerobic bench scale treatability units. It is evident that the
high degree of treatment of egg processing wastewaters for the purpose
of direct discharge to surface waters can be achieved most easily by
the combination anaerobic-aerobic lagoon treatment. Anaerobic-aerobic
lagoons are advantageous from the standpoint of low maintenance
requirements, energy requirements and capital costs. Treatability
studies have shown that the two-lagoon system is capable of producing
an effluent of low turbidity with good solids settling characteristics
and extremely low oxygen demanding substances.
The anaerobic-aerobic system is a unique system in that the sludge
production of an anaerobic lagoon is less than the sludge production
of a strictly aerobic system. Removal of solids from the effluent from
the aerobic lagoon would result in an effluent quality which would
qualify for direct discharge in most areas. The total BOD5 would be
less than 20 mg/a, SS less than 20
There are a number of design considerations involved with full scale
operation of anaerobic-aerobic systems. Bench scale studies indicated
that a scum layer will form on the anaerobic lagoon and retain odors
associated with the system. It is not known how stable this scum
layer will be under field conditions.
The alkalinity in the anaerobic lagoons treating egg wastes often had
a relatively low value (200-800 mg/£-CaC03). When the effluent
from the anaerobic lagoon enters the aerated unit the nitrifying organ
isms consume bicarbonate and also release hydrogen ions in the oxida-
153
-------
tion of ammonia nitrogen to nitrate nitrogen. Experience has shown
that the aerated lagoon may need additional sources of inorganic
carbon.
Another possible drawback of these systems is the possible impact of
low temperatures on treatment plant efficiency. At temperatures lower
than 10°C, the removal capacity of this combination may be diminished
even though the organic removal efficiencies were nearly the same at
20°C as they were at 10°C
The design procedure for the lagoons is simplified because of the fact
that the substrate removal coefficient, K, was nearly the same for
anaerobic and aerobic lagoons (0.63 day" versus 0.67 day" , respec-
tively), and also because there appeared to be no significant effect
in effluent total COD quality when the temperature was decreased from
20°C to 10°C.
A common parameter determined for most of the bench scale operations
was turbidity and this measurement provided the most impressive differ-
ence between treatment systems. Figures 43 and 44 give comparisons of
effluent turbidity for a variety of treatment processes. The anaerobic-
aerobic systems provide an effluent quality superior to effluents of
aerobic biological treatment. Aerobic treatment processes produced
highly turbid effluents due to dispersed solids and a residual yellow-
brown color.
Although process selection for each plant should be examined carefully,
and treatability studies conducted to determine specific requirements,
the combination lagoon system had a greater capacity than other systems.
A system that could meet effluent BODg and SS requirements of 20 mg/£
each is shown in Figure 45. This system would combine a 3 cell 20 day
HRT anaerobic lagoon with a 3-cell 6 day HRT aerated lagoon. Only
3 cells are recommended as a comprise between the advantages of series
154
-------
AERATED LASOON ANAEKOBIC
10 da
AERATION
FIGURE 43. Comparison of clarity of effluents produced by
various treatment processes.
155
-------
en
cr>
100
£? 80
*\
t 60
O
m
vX\
II
;:£•:
::•:•:•:
x-S
ivX;
•::•:••:
•A-l-i
Sjii;
::•:•:;:
200}
:-S?
jijij;:;
ixx';
•:•:•:•:•
j;i|i|:|
x*x*:
•X*X*
wS
•::$•:•
x¥l
:•:•:•:• •
ivi'-i?
•x'-S :
•X'M
•:•'.•:••.
::•:•:•:
;X;X
?:5
:•:•:•:
0
r
o 2
0 T FWl 0
~ 8 III; ~
m Hi 111 lii
7 4 20830 IODAY 1.4 3.1 7.3
(SR^DAYS) . 5CELL (Ib COD/lOOOf t2)
ACTIVATED
SLUDGE
(HRT.DAYS)
AEROBIC
LAGOON
RBC
PROCESS
(HRT DAYS-TEMP °C)
ANAEROBIC-AEROBIC
LAGOON
FIGURE 44. Summary of effluent turbidity from various aerobic and
anaerobic-aerobic treatment systems.
-------
ANAEROBIC LAGOON
(20 DAY HRT)
AEROBIC LAGOON
(6 DAY HRT)
LIQUID SOLIDS
INFLUENT-
en
•*-
I
—
V
(
/ oc.r«n«iiwn
SLUDGE RECYCLE
FIGURE 45. A recommended wastewater treatment system to achieve maximum organic
pollution control of egg breaking wastewaters.
-------
treatment and the impact of shock loads. The design flow would be
based on the maximum production capacity projected for the months
of May, June and July.
Data obtained from the treatment of egg processing wastes using
aerobic treatment has shown that a HRT of 30 days for an aerated la-
goon will not produce a quality effluent suitable for direct discharge
to surface waters. The suspended solids settled poorly and remained
at high levels in the effluents.
The activated sludge process was examined and the results indicated
that the soluble COD of the effluent could be reduced to 100 mg/fc,
but the system had faults similar to those encountered in the use of
aerated lagoons. The resulting mixed liquor solids were poorly floc-
culated and did not settle. Suspended solids were observed to reach
400 mg/£ in the clarified effluent.
The RBC system provided an effluent suitable for discharge to a
municipal system, but only at low organic loadings of 3 Ib COD/1000 ft2.
Lower loadings may be capable of producing a high quality effluent, but
3 Ib COD/1000 ft2 is less than that used in most applications of this
process. At this low loading the costs of treatment may exceed the
discharge surcharge.
In an earlier portion of this report dealing with the characterization
of egg processing wastewater it was shown that for plants A and B, the
ratio of BOD:N:P is less than the ratio of 100:5:1 which is necessary
to accomplish aerobic stabilization of wastewaters. Bench scale
aerobic processes operated in this study were fed with wastes from
Plants A and B and at times the phosphate concentration would approach
zero thus indicating a phosphate deficiency for aerobic processes.
Since the cell yield of anaerobic bacteria is less than those of aerobic
organisms, the amount of phosphorus needed by anaerobic biological
158
-------
systems is. substantially less than the BOD:N:P ratio of 100:5:1. Phos-
phate concentrations 1n the aerobic lagoons following anaerobic lagoons
were determined periodically and indicated that sufficient phosphate
was present to ensure complete treatment without additional phosphorus.
Due to increased environmental awareness, more environmental engineers
will be faced with the design of treatment systems to handle an ever
increasing population. Often times municipal systems are aerobic treat-
ment processes, and if an industry such as an egg breaking plant dis-
charges to this particular plant, there may be difficulty in meeting
regulatory effluent guidelines. Experience from this study indicated
that poor effluent quality can be expected when treating egg processing
wastes aerobically. Thus complaints from operators of municipal aerobic
plants will often occur when egg breaking plants contribute sizeable
portions of the total organic loading. In the town where plant E is
located, there does not seem to be a problem with the operation of the
municipal trickling filter, but the egg processing wastes constitute
less than 10 percent of the municipality's organic loading.
159
-------
PART IV
REFERENCES
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2. New York Crop Reporting Service. New York Agricultural Statistics,
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3. Department of Agricultural Economics. Agricultural Situation and
Outlook. N.Y. Economic Handbook, 1974. New York State College of
Agriculture and Life Sciences, AE Ext. 73-24. December 1973.
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Costs 1951-69. Marketing Research Report No. 917. U. S. Department
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5. Poultry and Egg Situation. Economic Research Series, P ES-274.
U.S. Department of Agriculture, Washington, DC. November 1972.
6. Jasper, A. W. Some Statistical Highlights of the Poultry Industry.
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8. Bureau of Census. United States Census of Agriculture, Livestock
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9. Agricultural Statistics. U.S. Department of Agriculture. 1972.
160
-------
10. United States Energy Fact Sheets 1971 by States and Regions.
U.S. Department of the Interior. Washington, DC. February
1973. 138 p.
11. Rogers, G. B. Vertical and Horizontal Integration in the Market
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Stat. 1620 etseq 21 U.S.C. 1031-1056). 91st Congress, 2nd session.
December 1970.
13. Kondele, J. W. and E. C. Heinsohn. The Egg Products Industry of the
U.S. Part 2, Economic and Technological Trends 1936-61. North Central
Regional Research Publication No. 154. Bulletin 466. Agricultural
Experiment Station. Kansas State University. Manhattan, danuary
1964.
14. Jones, H. B. and H. R. Smalley. Vertically Integrated Methods of
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N.S. 160. Georgia Agricultural Experiment Station. Athens. May
1966.
15. Deleted.
16. Statistical Research Service. Egg Products, February 1968-April
1971. U. S. Department of Agriculture. Washington, DC.
17. Jasper, A. W. Marketing of Eggs, Farm Chickens Involve Many Inova-
tive People. In - American Poultry History 1823-1973. American
Poultry Historical Society. 1974. Chapter 10, p. 306-369. Mount
Morris, Illinois.
18. Stadelman, W. J. and 0. J. Cotterill (eds.). Egg Science and
Technology. AVI Publishing Co., Westport, Conn. 1973. 314 p.
161
-------
19. U.S. Department of Agriculture. Egg Grading Manual. Agric. Hand-
book, No. 75. (Revised) April 1972. Washington, DC.
20. Johndrew, 0. F., Jr., H. R. Davis, and R. C. Baker. Liquid and
Frozen Egg Processing. Misc. Bull. 97. New York State College
of Agriculture and Life Sciences, Cornell University. Ithaca.
February 1971.
21. Bezpa, J., 0. F. Johndrew, 6. H. Thacker, R. M. Grover, F. V. Muir
and C. A. Dupras. Field Studies on Eggshell Damage and Bloodspot
Detection. Rutgers University. New Brunswick, New Jersey. Exten-
sion Bulletin 403. 1972. 31 p.
22. Kaufman, V. F., D. H. Bergquist, K. Ijicki and A. L. Porter. Waste-
water Control at Egg Products Plants. An Informal Report from the
Poultry & Egg Institute of America and the U. S. Department of
Agriculture. Washington, DC. 1974. 11 p.
23. Forker, 0. D., M. Chayat, and B. Shaul. Toward the Year 1985:
Egg and Poultry Production. Special Cornell Series 11. New York
State College of Agriculture and Life Sciences, Cornell University.
Ithaca. 1970.
24. Stevens, J. C. Hydrographic Data Book. 8th edition. Portland,
Oregon, Leupold & Stevens Inc. 112 p. 1970.
25. Zall, R. R. and W. J. Toleman. Wastes from Egg Packing-Breaking
Plants. Unpublished Report. Department of Food Science. Cornell
University. Ithaca, New York. 1972.
26. Baker, R. C. and D. V. Vadehra. Factors Affecting the Quantity of
Residual Albumen in Eggs. Poultry Science 49_:949-953. July 1970.
162
-------
27. Dekleine, H. and G. P. Frtskorn, Research into the Wastewater
Disposal Situation in Egg-Breaking Industries. State Agriculture
Waste Disposal Service Report No. 4372. Inst. for Poultry Research.
September 1972. 32 p.
28. Kraft, A. A., G. S. Torrey, J. C. Ayers and R. H. Forsythe. Factors
Influencing Bacterial Contamination of Commercially Produced Liquid
Egg. Poultry Science 46_: 1204-1210. September 1967.
29. NEPCO Began Drying Shell Wastes to Improve Relations in Community.
Egg Industry. 6:26-28. April 1973.
30. Walton, H. V., 0. J. Cotterill and J. M. Vandepopuliere. Cashing
in on Breaking Plant Wastes. Egg Industry. 6:25-26. April 1973.
31. Walton, H. V., 0. J. Cotterill and J. M. Vandepopuliere. Egg Shell
Waste Composition. University of Missouri-Columbia. (Presented
at winter meeting American Society of Agricultural Engineers.
Paper No. 72-886. Chicago, Illinois. December 11-15, 1972.).
32. Hamm, D., G. K. Searcy and A. J. Mercuri. A Study of Waste Wash
Water from Egg Washing Machines. Poultry Science. 53:191-197.
1974.
33. Loehr, R. C. Liquid Waste Treatment II: Oxidation Ponds and
Aerated Lagoons. Proceedings 1971 Cornell Agricultural Waste
Management Conference. Syracuse, New York. pp. 63-71. 1971.
34. Loehr, R. C. Agricultural Waste Management - Problems, Processes,
Approaches. Academic Press, New York. 1974. 576 p.
35. Eckenfelder, W. W., Jr. Water Quality Engineering for Practicing
Engineers. Barnes and Noble Inc., New York. 1970.
163
-------
36. Metcalf and Eddy, Inc. Wastewater Engineering, Collection, Treat-
ment, Disposal. McGraw-Hill Book Co., New York. 1972. 782 p.
37. Jenkins, D. and W. E. Garrison. Control of Activated Sludge by
Mean Cell Residence Time. Jour. WPCF. 40(11):part 1. 1968.
38. Birks, C. W. and R. J. Hynek. Treatment of Cheese Processing
Wastes by The Bio-disc Process. Proc. Purdue Industrial Waste
Conference. Lafayette, Indiana. Engineering Extension Series
No. 140. pp. 89-105. 1971.
39. Antonie, R. Application of the Bio-disc Process to Treatment of
Domestic Wastewater. (Presented at 43rd Water Pollution Control
Federation Conference, Boston, Massachusetts. 1970.).
40. Weng, C. and A. H. Molog. Nitrification in the Biological Fixed
Film Rotating Disc System. Jour. WPCF. 46(7):1674-85. July 1974.
41. Kornegay, B. H. and J. F. Andrews. Kinetics of Fixed Film Biological
Reactors. Proc. 22nd Industrial Waste Conf., Purdue University.
1967.
42. Porges, R. Industrial Waste Stabilization Ponds in the United States.
Jour. WPCF 35:456. 1963.
43. Missouri Basin Engineering Health Council. Waste Treatment Lagoons-
State of the Art. Cheyenne, Wyoming. Water Pollution Control
Research Series EPA-17090EHX07/71. U. S. Environmental Protection
Agency, Washington, DC. 1971.
44. Rollag, D. A. and J. N. Dornbusch. Anaerobic Stabilization Pond
Treatment of Meat Packing Wastes. Proc. 21st Purdue University Ind.
Waste Conf. Lafayette, Indiana. Ext. Ser. 121. 1968.
164
-------
45. Stensel, H. D. and G. L. Shell. Two Methods of Biological Treat-
ment Design. Jour. WPCF 46(2):271-283. February 1974.
46. Lawrence, A. W. and P. L. McCarty. Unified Basis for Biological
Treatment Design and Operation. Jour. San. Eng. Div., Proc. ASCE
96, (SAE):757. 1970.
47. Knowles, G., A. L. Downing and M. J. Barrett. Determination of
Kinetic Constants for Nitrifying Bacteria in Mixed Cultures with the
Aid of an Electric Computer., Jour. Gen. Microbiology 38:263-78. 1965.
48. Wild, H. E., C. N. Sawyer and T. C. McMahon. Factors Affecting Nitri-
fication Kinetics. Jour. WPCF 43(9):1845-1854. September 1971.
49. Lawrence, A. W. and C. G. Brown. Biokinetic Approach to Optimal De-
sign and Control of Nitrifying Activated Sludge Systems. Presented
at Annual New York Water Pollution Control Assoc. New York, New
York. January 23, 1973.
50. Standard Methods for the Examination of Water and Waste Water.
American Public Health Association, New York. 1971. 874 p.
51. Prakasam, T. B. S., E. G. Srinath, P. Y. Yang and R. C. Loehr.
Evaluation of Methods of Analysis for the Determination of Physical,
Chemical and Biochemical Parameters of Poultry Wastewater. Presented
at American Society of Agricultural Engineers Committee SE-42,
Chicago, Illinois. 1972.
52. Jeris. J. S. A Rapid COD Test. Water and Waste Engineering.
4:89. 1967.
53. Consumer and Marketing Service. Regulations Governing the Grading
of Shell Eggs and U.S. Standards, Grades and Weight Classes for Shell
Eggs. (7 CFR, Part 56). U.S. Dept. of Agriculture. July 1971.
165
-------
PART V
GLOSSARY
TERMS
Breaking - refers to the physical separation of the inner contents of
shell eggs from the shell and shell membranes by machine or by hand.
Breaking plant - a plant in which shell eggs are broken,.pasteurized
and otherwise prepared for the production of liquid and frozen and/or
egg solids.
Breaking stock - shell eggs used for breaking.
Case of eggs - usually refers to a standard egg case holding 30 dozen
eggs. There are egg cases on the market that hold 24 and 28 dozen eggs.
The "U.S. Weight Classes For Consumer Grades for Shell Eggs" are given
below (6).
Min. net Min. net Min. wght. for
Size or wght per doz. wght. per 30 doz. indiv. eggs @
Wght. Class rate per doz.
(oz.) (Ibs.) (Ibs.) (oz.)
Jumbo
Extra Large
Large
Medium
Small
Peewee
30
27
24
21
18
15
1.87
1.69
1.50
1.31
1.13
0.94
56
50 1/2
45
39 1/2
34
28
29
26
23
20
17
"••
Checks - an individual egg that has a broken shell or crack in the shell
with its shell membranes intact and its contents do not leak.
Egg (or shell egg) - means the shell egg of the domesticated chicken,
turkey, duck, goose or guinea (12). (In this publication "egg" usually
refers to an egg from a chicken. )
166
-------
Egg meats - the content of a shell egg including the yolk and the albumen
but excluding the shell membranes and the shell (4).
Egg or shell egg processing plant - usually refers to a plant where shell
eggs are washed, graded for size and quality and packed.
Egg products - whole eggs, whole egg blends, whites and yolks in liquid
and/or fcozen or dried form (4) (13).
Egg Products Inspection Act - a federal law providing for the mandatory
inspection of certain egg products, restrictions of certain qualities
of the eggs, and uniformity of standards for eggs and otherwise regulate
the processing and distribution of eggs and egg products, etc. (12).
Egg solids - a term used synonomously with dried eggs. There are many
types but the most common are whole eggs, albumen, whole egg blends and
yolk solids (4).
Emulsion - an oily mass in suspension in a watery liquid. For example,
salad oil is an emulsion of egg yolks mixed with water, starch, vege-
table oils and spices (4).
Frozen whole eggs - a mixture of whites and yolks in natural proportions,
as broken, with no additives, which have been frozen solids. There are
also frozen whites, frozen plain yolks, frozen sugared yolks, etc. (13).
Integration or coordination - may be generally defined as the tying
together of firms and/or functions through contracts, agreements or
ownership.
Leakers - an individual egg that has a break in the shell and shell
membranes to the extent the egg contents are exuding or free to exude
through the shell (53).
167
-------
Official plant - refers to any plant as determined by the Secretary of
Agriculture (U.S.) or the Administrator of the Consumer and Marketing
Service (U.S.D.A.) where inspection and/or grading service is maintained
or conducted by the U.S. Department of Agriculture (12) (53).
Pasteurize - means to subject egg products to heat or other treatments
to destroy harmful, viable microorganisms by such processes as might
be described by the regulations of the Egg Products Inspection Act (12).
Poultry - domesticated chickens, turkeys, ducks, geese or guineas.
168
-------
APPENDIX A
SUMMARY OF HISTORICAL AND TECHNOLOGICAL DEVELOPMENTS
AND THEIR RELATION TO OPERATING PROBLEMS
SHELL EGG INDUSTRY
Marketing
1800 to 1850 History shows a primitive beginning in the 1800's. Eggs
were used as gifts to friends or barter at the general
store. References to egg weights and size of air cells
were made.
1850 Eggs were packed with small end down.
1859 An article in "Curiosities of Food" by P.L. Simmonds
noted the novelty of candling eggs in New York City.
1862 Grades were quoted in 1862, but only by areas of origin.
1875 The Butter and Cheese Exchange was enlarged to cover the
needs of egg merchants. The Pet-Stock, Pigeon and Poultry
Bulletin indicated in May 1875 a grading system classi-
fying eggs as Extras, Firsts, and Thirds.
1878 The American Poultry Yard discussed egg flavor.
1900 to 1925 Frank G. Urner, editor of American Creamery and Poultry
Produce Review worked for conformity of commercial grading
system. L.B. Kilbourne of the National Poultry, Butter
and Egg Association set up meetings to develop standards.
1922 The Capper-Volstead Act provided a temporary delay in the
adoption of national standards.
1923 First draft of proposed standards was written. It was
adopted in 1925.
1932 An "Approved Buying Grades for Eggs" was adopted in the
midwest.
169
-------
1934 The U.S.D.A. issued official standards with legal status
in February 1934. A pictorial chart was developed showing
variation in quality of fresh laid eggs.
1937 The Hough unit for measuring the height of albumen was
established.
1939 Federal standards were revised giving letter designations
to grades.
1941 to 1945 The Armed Forces created new procurement grades during
World War II.
1956 Harry E. Drews of San Diego Cooperative assembled the first
underlight candling equipment.
1959 The U.S. Fresh Fancy Quality grade was adopted.
1960's Bulk or mass candling becane common in the 1960's. Govern-
ment agencies began emphasizing the significance of
salmonella organisms in eggs and egg products. Studies
were carried out at Iowa State University showing the
effects of clean versus soiled packaging materials.
1970 Congress passed the Egg Products Inspection Act in
December.
1972 The shell egg part of the Act went into effect in
July. The Act was amended in November to provide
a classification of "nest run eggs."
Egg washing
1898 The New York Produce Review noted that packers were
washing dirty eggs.
1933 Almquist designed a test to detect the cleaning of eggs
by abrasives and by washing.
1945 Hand methods were used to wash eggs until some earlier
models of egg washing machines were introduced near the
end of World War II.
170
-------
1949 The U.S.D.A. studied washing and storage of dirty shell
eggs. Dr. Forsythe of Iowa State University predicted
all eggs would be washed in all channels of trade.
1950's F.B. Wright of Cornell University developed one of the
first acceptable automatic egg cleaners in the 1950's.
1960's A broad research program by Brant and Associates resolved
the fundamental requirements for safe egg washing.
Packaging
1800's The early container for eggs was the keg containing 70
dozen eggs packed in oats, straw or similar materials.
Eggs were repacked into wooden boxes holding 40 dozen
eggs without packing material and delivered to stores.
1870's Sawn wood (30 and 36 dozen) egg cases came into common
use.
1873 W. Weiss of the Central Fibre Products Company patented
an egg case filler with a lock-strip that would secure
the eggs in individual protective cells.
Early 1900's The 30 dozen case became more popular because it was
easier to handle and just about as economical as the larger
case. Egg cases made from veneer wood began appearing on
the market. Simple strawboard fillers and flats were used
to hold the eggs in the case.
1912 Fillers made with newsboard which were manufactured from
old papers, cardboard from solid pulp, and filled pulp
(utilizing reclaimed newspapers) were developed and used.
1925 The "Mapes molded pulp cup flat" was introduced. This
was the most significant development in egg packaging.
This flat used with the filler (1873 above), invented
by Weiss, was the turning point in the handling, shipping
and overall protection and storage of eggs.
The Keyes Fibre Company made a molded pulp pad flat.
171
-------
1930's The Hartman Company of Denmark invented the first filler-
flat (egg trays) using alternate layers of 20 and 30 eggs
and marketed them in Europe.
1931 The Keyes Fibre Company invented a variation of the filler-
flat (egg tray) and marketed this product in Canada and
the United States.
1940 During World War II, wooden cases were replaced by fiber.
egg cases. After World War II the features of the molded
pulp cup flat and filler were combined into one piece.
Car Pro invented a device to automatically lift eggs from
the filler-flat. Filler-flats became much more acceptable
to the trade.
1950's Plastic filler-flats were introduced.
Automation &_ mechanization
1900 A.J. Murdock of P.W. Kiefabor and Company in Philadelphia
patented an "American Improved Testing Machine" ("multi-
egg candling device").
1939 One of the first automatic graders was.developed and
demonstrated by Mr. Otto Niederer, Sr.
1950's There was a continued development of equipment until the
innovations in the fifties and sixties. Automatic egg
washers, mass candling techniques, egg sizing devices and
automatic cartoning were the major changes.
1953 The first bloodspot detector was developed and patented
by the U.S.D.A.
I960 H.D. Bartlett of Pennsylvania developed one of the earliest
experimental egg packers. George Page later perfected
one of the first commercial applications.
172
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EGG PRODUCTS INDUSTRY
Egg breaking operations
Late 1890's First attempts to break and freeze eggs were made inde-
pendently of each other by H.J. Keith and T.S. White.
Early 1900's Sugar added to yolks prior to freezing to prevent
gelatin (H.J. Keith).
1907 Basic and applied research undertaken on principles
of sanitation and refrigeration of broken-out eggs by
Dr. M.E. Pennington and staff.
1912 Invention by H.A. Perry of the egg separator which
separates whites from yolks.
1926 Salt added to yolks before freezing to prevent gelatin
(T.M. Rector).
1935 Development by J.M. Vansant of an impeller-type liquid
egg churn.
1938 First commercial pasteurization of liquid eggs by
Henningsen Brothers.
Late 1930's Invention of the "Irish" sucker which removed remaining
edible whites from shells (J.C. Irish). Improvements
made by J.M. Vansant.
Dairy-type strainer adapted to strain out pieces of shell
and chalazae from liquid eggs.
1943 Invention of first commercial egg breaking machine
(L. Sigler). Manufacture began in 1949-50 by the
Barker Poultry Equipment Company.
1952 Invention of second commercial egg breaking machine
(C.H. Willsey).
Early 1950's Development of an automatic egg breaking machine in the
early 1950's by Jay Odell and O.R. Anderson of the Seymour
Packing Co.
173
-------
1966 Heat pasteurization of eggs was required in U.S.D.A.
inspected breaking plants.
1970 Congress passed the Egg Products Inspection Act in
December.
1971 The egg products part of this Act went into effect on
July 1. This required rather rigid sanitary and
operational practices in breaking plants. A resident
U.S.D.A. inspector has to be in each plant.
174
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APPENDIX B
IMPORTANCE OF EGG WASHING
The value of washing eggs for egg breaking purposes should be examined
in further depth. While monitoring in-plant egg washing losses it was
suspected that egg washing methods could contaminate rather than clean
eggs in some operations. Most eggs after an hour's run 'are being
washed in soiled cleaning water. Since egg shells are porous it seems
probable that washing methods may contaminate rather than clean some
egg breaking stock.
A series of egg washing experiments were carried out in two egg breaking
plants in April and May to determine microbial contamination of egg
shells and egg products.
SAMPLING METHODS
1. Six eggs randomly sampled from the loading belt before egg washing
machine were washed in 300 ml sterile distilled water. The washings
were diluted and plated on standard plant count agar according to the
Standard Methods.
2. Six eggs randomly sampled from the belt after being machine washed
were washed in 300 ml sterile distilled water. The washings were used
as above at start up and at shut down 4 hours later.
3. Six eggs randomly sampled from the belt after chlorine sprayed were
washed in 300 ml sterile distilled water and the washings were processed
as above (1 and 2) at hourly intervals.
4. A sample of liquid egg was taken at hourly intervals in a sterile
container as soon as the liquid egg left the egg breaking machine and
dilutions of the liquid eggs were processed as 1, 2 and 3 above.
5. Rinse water of egg breaking machine at start up was sampled after
175
-------
the egg breaking machine was sanitized and rinsed. Samples of the rinse
were processed as 1, 2, 3 and 4 above.
6. Rinse water of the egg breaking machine was sampled after 4 hours
of operation when the egg breaking machine was washed. A sample of
this wash water was processed as above.
7. Rinse water of the egg breaking machine was sampled after the egg
breaking machine was washed, sanitized and rinsed. A sample of this
rinse was processed as 1, 2, 3, 4, 5, and 6.
8. Egg washing machine wash water overflow samples were taken at hourly
intervals and processed as above samples.
9. The washing solution of the egg washing machine was sampled after
it had been in operation for 4 hours.
The numbers of microorganisms per ml of waste water, washings, or per
gram of liquid in Plant A are given in Appendix Table 1.
Appendix Table 2 shows data from Plant B. Sampling times were different
due to time of day start up and was conducted at 11:30 A.M. - 3:30 P.M.
Samples were taken at the same-basic sampling locations. Samples were
processed as in part one. This plant used a different sanitizing system
so samples 5, 6 and 7 were not comparable between plants. During the
sampling period, this plant processed eggs which were brought to the
plant washed. The washing unit's brushes were used on two occasions
(May 20 and 21 as shown by asterisk).
Wastewater of the egg washing machine at Plant B contained numerous
pin-point colonies which were present even at the zero time of operation.
Since this indicated microbial seeding in the system, we prepared addi-
tional samples for incubating thermoduric microorganisms. These
organisms in wastewater did not grow at 55°C which seem to cancel out
thermophiles. It is believed that pin-point colonies had become
established in the wastewater tank and survived chlorination. These
organisms are sometimes present in liquid egg samples.
176
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Appendix Table 1. 'TOTAl/BACTERIAL COUNTS Off SPC AGAR OF THE F.G(( PROCESSING PLANT A
Tint Sn«ale« 4/11/74 4/12/74 4/15/74. 4/lo/74 4/IS/74 4/19/74 A/23/74* 4/24/74 4/25/74 A/26/74
Wit«r-u«eh (Tlaw eggg
6/300 ml of UjO)
UtttT-vath (Egga nach.
washed 6/300 el HiO)
Water-wash (Eggs after
chlorine 6/300 ml H,0)
Liquid egg (IB it
leaves the egg
breaking machine)
Rinse of egg breaking
math, after sanitizing
Rinse of egg breaking
nuch. nftec operation
Rinse of ejg breaking
sach. after sanitizing
Overflow of wastewater
Wastcuater frou egg
vtishlng niachina
8
8
12
8
9
10
11
12
a
9
10
11
12
8
12
12
8
9
10
11
12
12
1
2
30
3,
3.
3,
3,
4.
4i
4j
4)
4»
5
6
7
8,
B!
8, •
8j
«»
9
4.100.00C
700,000
. 210.000,
69.000
1,460,000
21,000
27,000
43,000
295,000
2,200,000
3,000,000
9
1,600,000
490
280,000
300,000
2,000,000
7,000,000
28,000,000
340,000,001
9,300,000
5,500,000
1,350,000
700.000
1,360,000
420,000
27,00f>
84,000
31,000
190,000
2,640,000
15
5,300,000
130
3,600,000
9,000,000
4,100,000
2,750,000
10,000,000
430,000,000
2,710,000
940,000
(3,500,000;
770,000
270,000
1/iO.OQO
185,000
150,000
59,000
190,000
85,000
115,000
178,000
20
940,000
45
235,000
143,000
310,000
245,000
40D, 000
290,000,000
3,100,000
620,000
(2.S60.000)
4,200, goo
6,300.000
5,600.000
«
7,100.000
2,450,000
3,100,000
1,950,000
—
2,490.000
33
850.000
39
3,100,000
5,400,000
4,100,000
. «...
5,900,000
J90, 000,000
1,900,000
1,780,000
(2,210,000;
970
180
31
30
42
15
30
38
180
98
18
'1,230,000
24
77,600
23,400
19,100
7,900
16,200
245,000,000
830,000
800,000
(2,700,0001
2,530
1,730
840
98
39
1,600
550
2,980
300
256
32
2,300,000
65
14,000
9,000
11,500
10,800
16,900
160,000,000
4,200,000
249,000
(1, 450,000;
58,000
110,000
6,000
21,000
113,000
6,900
53,000
7.200
,,
9,900
5
1,900,000
167
A
205,000
285,000
470,000
580,000
970,000
259,000,000
1,970,000
440.000
(910,000)
1,150
880
560
910
470
1,850
2,150
950
770
2,450
8
880,000
123
. 1,230,000
790,000
810,000
1,050,000
940,000
410,000,000
1,950,000
203,000
(1,100,000
f
230,000
96,000
110,000
24,000
138,000
51,000
103,000
189,000
59,000
77,000
0
1,230,000
201
1,100,000
790,000
800,000
154,000
227,000
210,000,000
3,500,000
450,000
(2,100,000)
127,000
56,000
231.000
78,000
69,000
72,000
24,000
93,000
21,000
27,000
63
1,900,000
173
l', 890. 000
1,780,000
560,000
4.500,000
3,900,000
350,000,000
*Brushca were used
-------
Appendix Table 2. TOTAL BACTERIAL COUNTS ON SPC AGAR OF THE EGG PROCESSING PLANT B
00
Water va«h (R«v egge
6/300 al)
Water Vi»h (Eggl much.
washed 6/300 ml)
Watar wash (Egge after
chlorine 6/300 al)
liquid egg
Rinse of egg breaking
nach. after sanitizing
Rinse of egg breaking
each, after operation
Not taken
Whitewater Iron egg
washing machine
*8ru«he» were ueed
•JteL
3115
JllS
11:30
12:30
1:30
2:30
3:30
11:30
12)30
1:30
2:30
3:30
11:30
3:30
11:30
12:30
1:30
2:30
3130
Sample. 4/30/74 5/1/74 V*/™ -i/J/74 i/8/74 5/9/74
1
2
3e
3t
3i
3i
3,
4.
4j
4i
4,
4,
5
6
7
8,
81
81
81
8*
20,000
90,000
81,000
154,000
450,000
88,000
770,000
50,000
63,000
7,400
83,000
21,500
0
9,000,000
15,300,000
281,000.000
135,000,000
4,800,000
28,400,000
283,000
178,000
4,200
158,000
98,000
166,000
88,000
18,000
150,000
5,900
115,000
51,000
0
11,900
250, 000, OOC
165,000,000
200,000,000
116,000,000
WO, 000, 000
140,000
76,000
183.000
45,000
205,000
9,200
150,000
8,400
160,000
5,500
20,500
17,500
10
77,000
1,390,000,000
2,100,000,000
2,400,000,000
2,600,000,000
3,040,000,000
290,000
190,000
n,40a
m'.ooo
911,000
111,3011
147.00(1
1,9011
111,000
411,00(1
13D
60,00(1
245.OCO.OHC
190, 000, OriC
210,0(0, OUC
17 0,000, OIK
Z*00,000,0(K
135,000
69,000
181,000
40,000
210,000
90,000
41,000
7,900
164,000
5,200
21,000
17,000
19
210,000
430,000, OOC
290.000.00C
WO, 000 ,000
2JCO.OOO/DO
3000, 000 tf>0
60,000
lt>t (ample
2:30
19,000"
24,000
21,000
33.000,
laat eample
2(30
1,490
880
17,200
2,900,
1,760
87
165,000
2,040,000-
1,850,000
1,790,000
23,000,OOCV
26,400,000
V70/74,,
1,300,000*
40,000
>no-«aaple»
4,500
no ennpleit
140,000
850,000
>no samples
53,000,000
S/21/74
3,600,000'
280,000
29,000
110,000
42,000
170,000
80,000
21,000
19,000
53,000
11,000
242,000
1,800
1,300,000
11,500,000
19,500,000
' 24,000,000
25.000,000
23.000,000
S/22/74
65, OOC
120,000
38, OOC
74, OOC
55,000
19, OOC
21, OOC
1,950
4, OOC
2,150
37,000
120, OOC
1,760
90, OOC
62,000,000
74,000,000
65,000,000
69, 000, OOC
71,000,000
S/23/74
91,000
13,000
140,000
110,000
90,000
120,000
83,000
5,000
3,000
33,000
9,700
4,200
900
145,000
| didn't use
; washing
) machine
1,550,000
-------
Although most of the eggs processed at this location were clean and
graded eggs, the wastewater had far greater numbers than the plant
in Appendix Table 1, which had not used detergent, but plain hot water
action alone removed microorganisms. Further investigation seems
warranted from these brief data. In Appendix Table 1, samples
3Q through 3. are particularly interesting. The data show egg surface
counts following washing and a chlorine spray. The chlorinator was
faulty during the five days of 4/11/74 through 4/16/74. These counts
suggest that chlorination rather then washing appears to be the more
valuable treatment.
179
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APPENDIX C
RECOVERY OF EGG WASTES FROM THE EGG WASHER
An egg-breaking system has many integral operations. One unit operation
in the system is egg washing. The egg washing function generates about
8.5% of the total liquid waste outflow of an egg-breaking system. This
does not seem to be a major contribution to the total waste unit it is
considered that it can contain as high as 30% - 50% of the total BOD5
generated by the total plant operation. This BOD5 is caused by eggs
broken and lost during the washing process.
Broken whole eggs represent almost all of the 1.5% total solids of the
egg washer waste. Reclamation of this waste would be of major importance
to an egg-breaking plant in two ways: 1) the BOD5 effluent of the plant
would be substantially reduced, 2) reclaimed waste would provide a high
protein material for use in animal feeds.
METHODS
During this study three methods for reclaiming the waste were tried,
each using concentrated waste. One method involved forming a slurry
with ground corn or acid whey powder while the other two were drying of
the concentrate with hot oil or a drum drier. The concentrate waste
was prepared by open kettle evaporation of the egg washer waste with
steam at 4 psig. Concentrates of 8:1 or 11:1 were produced with 11.6 %
and 16.2% total solids respectively.
The slurry method of recovery used the 8:1 concentrate as a base. The
slurry was formed by adding a weight of ground corn or acid whey powder
equal to the solids of the concentrate and heating to a boil for 5
mi nutes.
180
-------
Materials dried in the hot oil were the 8:1 concentrate, the ground corn-
egg waste slurry, and the acid whey-egg waste slurry. Drying was accom-
plished by injecting the material into oil at 204°C heated in a deep fryer.
The dried material was collected by screening of the oil using muslin
cloth.
Drum drying was accomplished using the 11:1 concentrate. A double drum
drier was fed the concentrate as it rotated at a speed setting of 3.5.
Steam was supplied at 60 psig. via a regulator valve. The dried material
was removed from the drum with "doctor" blades and collected.
RESULTS
The concentrates were made with relatively little trouble. Some problem
with foaming was encountered initially but as the concentration increased
the foaming dissipated. Some coagulation occurred in the 11:1 concentrate,
but this occurrence presented no problem for its use on the drum drier.
The slurry with ground corn had viscosity about 10,000 centiposes with
a wholesome-like yellow color. The acid whey-egg waste combination did
not form a slurry but was a heavy liquid. The ground corn-egg waste
slurry would lend itself well to drum drying although this was not done.
Drying by hot oil was troublesome and presented a problem of getting
rapid separation of the dried material in the bench-top apparatus. The
8:1 concentrate formed very small particles which tended to scorch
before separation from the oil. The acid whey egg waste mixture behaved
very similar to the plain whey concentrate. The ground corn-egg waste
slurry dried very well in the oil giving large particles which were
readily separated from the oil. All of the materials tended to retain
an excess of oil which could not be prevented with the equipment used.
181
-------
No problems were encountered with drum drying once the rate of feed was
properly adjusted. The concentrate coated the drums evenly and when
dried was removed easily by the "doctor" blades. The final product
had a light gray-brown color and a texture similar to that of dried
pablum.
DISCUSSIONS
The slurry method with ground corn, because of the simple technology
involved, lends itself to the small plant. The slurry could be
marketed to local farmers for animal feed thereby minimizing the added
cost of transporting a material such as this any great distance. For
the larger plant, with greater production capacity, the slurry should
be taken to a dry form for marketing over a greater area.
Use of hot oil for reclamation of the egg washer waste does not appear
to be applicable to the small plant. A large capital investment would
be necessary to acquire the specialized equipment for processing. A
large volume of product for processing would be necessary to justify
this expenditure. Although this investigation tended to show it is
feasible to dry the egg waste in the hot oil, further investigation
using the refined commercial process is necessary before final con-
clusions could be drawn.
The drum drier is able to produce a very desirable product from the egg
washer waste. Again, because of capital investment, this operation
is suited to the larger plants with greater volume and possibly drying
equipment already present.
Appendix Tables 3 and 4 show selected nutritional characteristics of the
products previously described.
182
-------
Appendix Table 3. COMPOSITION OF DRY EGG-WASHER WASTE
Constituent
Water
Protei n
Fat
Carbohydrates
Ash
gms/100 gms
4.0
58.33
23.65
5.07
9.03
Appendix Table 4. PROXIMATE COMPOSITION9 OF GROUND CORN-EGG
WASTE MIXTURE
Ground Corn-Egg Ground Corn-Egg
Constitutents Waste Slurry Waste, Dried,
gms/100 gms gms/100 gms
Water
Protein
Fat
Carbohydrate
Ash
77.0
8.18
3.34
9.83
1.18
4.0
34.14
13.95
42.73
5.16
aBased on calculation using U.S.D.A. Agric. Handbook No. 8 values
for ground corn.
183
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NEW PRODUCT DEVELOPMENT USING EGG WHITES
When the egg breaker separated whole eggs into whites and yolks it was
noted that whites were not handled as carefully as yolk solids and this
appeared to generate the major portion of losses for the run. Because
egg whites are mostly colorless they are not easily observed when lost
to the floors. Egg whites are valuable for use in puddings, milk shakes,
ice cream. The industry should look again for opportunities to use egg
whites in products which traditionally were strongholds for non-fat dry
milk or whey powders.
An illustration of one food reformulation to increase the use of liquid
egg white is shown with rice pudding. Whole eggs, normally used in
rice pudding, were deleted and two formulations using egg whites at
34.2% and 46.7% by weight were prepared. Both formulations rated well
by our food panel tasters. The 34.2% formulation had a more preferred
textural quality than the higher formulation. Liquid egg whites' impact
on the nutritional quality of the rice pudding indicates that the lower
calories, lower fat, and higher protein levels ought to make the re-
formulated products very appealing.
184
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TECHNICAL REPORT DATA
(I'lcasc read Instructions on the reverse before completing}
1. RtPORT NO.
EPA-660/2-75-019
3. RECIPIENT'S ACCESSION-NO.
4. TITLE ANDSUBTITLE
EGG BREAKING AND PROCESSING WASTE CONTROL AND
TREATMENT
5. REPORT DATE
Preparation March 1975
6. PERFORMING ORGANIZATION CODE
AUTHOR(S)
W.J. Jewell; H.R. Davis; O.F. Johndrew, Jr.; R.C. LoeHr
W. Siderewicz, R.R. Zall
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORG "VNIZATION NAME AND ADDRESS
Departments of Agricultural
Poultry Science
Cornell University
Ithaca, New York 14853
Eng., Food Science and
10. PROGRAM ELEMENT NO.
1 B B 0 3 7
11. CONTRACT/GRANT NO.
ROAP/TASK No. 21 BAA/
S-802174
12. SPONSORING AGENCY NAME AND ADDRESS
N.Y.S. College of Agriculture and Life Sciences
Cornell University
Ithaca, New York 14853
13. TYPE OF REPORT AND PERIOD COVERED
Final report - 6/15/73-8/28/74
14. SPONSORING AGENCY CODE
16. SUPPLEMENTARY NOTES
16. ABSTRACT Eleven percent Of the eggs produced in the U.S. are handled by egg breaking
facilities to produce more than 800 million pounds of various egg products annually.
:ive egg breaking plants were sampled which covered a size ranging from small installa-
tions to one of the largest. The wastewater was highly contaminated, with total COD
exceeding 6000 mg/fc or greater. The product loss average was 12.5 percent of the
weight of the processed product. Unit process losses were 0.034 kg 6005 and 7.5 liters
>er kg of egg liquid produced. In-plant waste conservation methods were demonstrated
to decrease BODs and wastewater volume losses by 50 and 24 percent, respectively. These
eductions in product loss resulted in recovery of product with a value between $250
md $500 per day for a medium sized facility. Treatment of the wastewater by the
ictivated sludge process and by aerated lagoons did not decrease the effluent pollutant
:oncentrations to levels acceptable for direct discharge. Aerobic lagoons with 30 day
IRT reduced the total COD from 5800 mg/A to 1000 mg/£. Of the four treatment systems
:ested, only a combination of an anaerobic lagoon followed in series with an aerated
agoon and a liquid solids separation step produced a dischargable effluent with solubl
JOD,- less than 15 mg/A.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Egg processing wastes, wastewater manage-
ment, aerated lagoons, anaerobic lagoons,
ictivated sludge, anaerobic-aerobic lagoon
system, BODg, COD, turbidity.
b.lDENTIFIERS/OPEN ENDED TERMS
Effect of mixing on treatnu
In-plant management versu:
end of pipe treatment.
c. COSATI Field/Group
nt.
19. DISTRIBUTION STATEMENT
Release unlimited
19. SECURITY CLASS (This Report)
21. NO. OF PAGES
196
20. SECURITY CLASS (Thispage)
22. PRICE
EPA Form 2220-1 (9-73)
U.S. GOVERNMENT PRINTING OFFICE: 1975—698-907 \1 REGION 10
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