c/EPA
Environmental Protection
Agency
Research and Development
Research Laboratory
•nnati OH 45268
March 1978
Elimination of Pollutants
by Utilization of
Egg Breaking
Plant Shell-waste
Environmental Protection
Technology Series
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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 nine series. These nine broad cate-
gories were establi-shed to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6, Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental 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.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-78-044
March 1978
ELIMINATION OF POLLUTANTS BY UTILIZATION OF
EGG BREAKING PLANT SHELL-WASTE
by
J. M. Vandepopull ere
H. V. Walton
W. Jaynes
0. 0. Cotterill
University of Missouri
Columbia, Missouri 65201
Grant No. S803614
Project Officer
Jack L. Witherow
Food and Wood Products Branch
Industrial Environmental Research Laboratory
Corvallis, Oregon 97330
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U. S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
This report has been reviewed by the Industrial Environmental Research
Laboratory-Cincinnati, U. S. Environmental Protection Agency, and approved
for publication. Approval does not signify that the contents necessarily
reflects the views and policies of the U.S. Environmental Protection Agency,
nor does mention of trade names or commercial products constitute endorse-
ment or recommendation for use.
ii
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FOREWORD
When energy and material resources are extracted, processed, converted,
and used the related pollutional impacts on our environment and even on our
health often require that new and increasingly more efficient pollution
control methods be used. The Industrial Environmental Research Laboratory-
Cincinnati (IERL-Ci) assists in developing and demonstrating new and
improved methodologies that will meet these needs both efficiently and
economically.
The project demonstrated technology that converts egg shell waste to
a by-product and determined the benefits in utilization of the by-product in
feed for poultry. The waste is now commonly disposed of on land which can
cause large discharges of oxygen demanding materials into surface waters.
For further information on the subject the Food and Wood Products Branch,
Industrial Pollution Control Division, IERL-Ci should be contacted.
David G. Stephan
Director
Industrial Environmental Research Laboratory
Cincinnati
iii
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ABSTRACT
Disposal of egg shell waste is becoming an increasingly serious
problem for the egg breaking industry in the United States. There are
approximately 150 egg breaking plants and they yield an estimated 50,000
tons of waste annually. At present, these wastes are disposed of in land-
fills or on farm land. Thkis method of disposal is becoming more difficult
because of objections due to the potential for pollution.
Laboratory studies of the material coupled with experiments to
determine its nutritional value as a feedstuff when fed to laying hens
showed that it had considerable potential. With this strong evidence that
egg shell meal could be a valuable by-product of the egg breaking industry,
plans to establish a field study in Missouri were successfully implemented.
This study was partially funded by the Environmental Protection Agency
beginning in March 1975. There were three significant aspects of the
project: (1) dehydration of egg shell wastes to produce egg shell meal,
(2) analysis of product and incorporation into layer rations, and (3)
feeding trials with production flocks.
A triple pass rotary drum dehydrator was installed at an egg breaking
plant. 'With appropriate engineering modifications a system for producing
egg shell meal from the breaking plant shell waste was developed. Egg
shell meal was produced from the total egg shell waste from the breaking
plant. This meal was utilized as a feedstuff by a local mill and incorpor-
ated into a layer diet. This diet was fed to several commercial flocks of
cage layers.
Appropriate data were collected to determine meal production costs,
yield of meal, feed produced, feeding data, and layer flock performance.
Five-day and 26-day BOD data were generated to determine the total pollution
potential of the product were it not entering commercial channels as a
useful by-product.
This report is submitted in fulfillment of project S803614 by the
University of Missouri, Agricultural Experiment Station as partially
funded by the Environmental Protection Agency. Work was completed as of
June 9, 1977.
iv
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CONTENTS
Foreword iii
Abstract iv
Figures vii
Tables viii
Acknowledgement ix
I. Introduction 1
II. Conclusions 2
III. Recommendations 3
IV. Plan of Research 4
V. Dehydrator Construction 5
Selection and Installation of Equipment 5
Utilities 6
Operational Experience 6
VI. Experimental Procedure 14
Feeding Study 14
Data Collection 15
BOD and COD 15
Formulation and Milling 15
VII. Results and Discussion 17
Microbiological Composition 17
Moisture Content of ESM 17
Retention Time in the Dehydrator 19
Chemical Composition 19
BOD and COD of ESM 21
Plant Production 24
Cage Layer Performance 24
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VIII. Economic Considerations 27
Basis for Cooperators Share of ESM Value 27
Ownership and Operating Costs 27
Value of Egg Shell Meal 29
IX. Feed Control Official Definition 30
References 31
Appendices
A. An Economic Analysis of the Dehydration of Egg Breaking
Plant Wastes (November, 1974) 32
B. Operating Procedure 35
VI
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FIGURES
Number Page
1 Dehydrator being unloaded at Kraft Plant in Neosho, Mo. 7
2 Dehydrator being placed in position 7
3 Cyclone installation 7
4 Processed egg shell meal diverter 7
5 Special 90° elbow for ESM dehydrator 8
6 Control panel for Heil dehydrator 9
7 Inedible egg liquid separator 9
8 ESM blend-back control gate 9
9 ESM blending-conveying system 9
10 Egg shell waste centrifuge by Seymour 11
11 Flow diagram of egg breaking plant and egg shell waste
processing 12
12 Granular ESM flowing from the cyclone collector .... 13
13 Destruction of microorganisms in egg breaking plant
waste during dehydration at various temperatures ... 18
14 Visual color scores for ESM after various retention
times 20
15 BOD content of one sample of ESM after various incubation
times 23
vii
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TABLES
Number Page
1 Diets Used in Field Studies Evaluating ESM 14
2 Suggested Formula Change for One Group of Ingredients . . 16
3 Moisture Level of ESM Processed at Various Temperatures . 17
4 Analyses of 15 Production Samples of Egg Shell Meal (Dry
Basis) 19
5 Average Amino Acid Composition of 15 Samples of Centrifuged
ESM 21
6 Egg Shell Waste Characteristics 22
7 Characteristics of Imhoff Cone Supernatant 22
8 Average Daily Production at Egg Breaking Plant Under
Study 24
9 Performance Data of Cage Layers Fed ESM and Number of
Layers Involved 25
10 Cost of Dehydrator Ownership Based on an Installed Cost
of $35,000 27
11 Cost to Process One Metric Ton of Dried Egg Shell Meal
Based Upon Actual Operating Costs (Missouri Field Install-
ation) Combined with Dryer Ownership Costs 28
12 Value of Centrifuged ESM Based on Various Corn-Soybean
Prices 29
viii
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ACKNOWLEDGEMENTS
Work covered by this project involved the cooperative inputs of staff
members from the Department of Poultry Husbandry, the Department of
Agricultural Engineering, the Department of Food Science and Nutrition, and
the Cooperative Extension Service.
Also acknowledge the following:
Dr. Dennis Sievers and the Ag. E. Waste Management Lab.
Jean Glauert and Craig McKinney and the Egg Technology Lab.
Kraft Foods, Neosho, Mo.
MoArk, Neosho, Mo.
Administrative support of Dr. J. E. Savage, Poultry Department
Financial input of the Mo. Agricultural Experiment Station
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SECTION I
INTRODUCTION
The magnitude of continental United States egg industry in 1973 was
291,827,000 laying hens. They produced 3,045 million kg of egg products.
In 1972, 11% of the shell eggs were broken in 152 egg breaking plants for
use in further processed egg products (1). From 1950, to 1972 the number
of egg breaking plants decreased from 477 to 152. During the same period
the total processed liquid egg production increased. With this increased
production in the egg breaking plants, there was an increase in the
quantity of plant waste produced at any one site. These plants yielded
some 45,454 metric tons of waste annually. The primary disposal methods
were in landfills and on farm land pastures.
The egg breaking industry is faced with an increasingly serious waste
disposal problem. The Egg Products Inspection Act (84 Stat. 1620 Et. seq.,
21 USC 1031-1056) was enacted December 29, 1970. On July 1, 1972, phase
two of this act became effective, controlling restricted shell eggs (checks,
dirties, leakers, incubator rejects, inedible and loss eggs). All of these
types of eggs, except checks and dirties, must be denatured or destroyed at
the point of segregation to eliminate them from the consumer food channels.
The above inedible eggs can be utilized in animal foods and at large
plants they are normally saved and sold to feed producers. The egg shells
from the breaking machines retain some of the egg liquid. At plants where
there is a market, these shells are centrifuged and the liquid portion sold
for animal foods. The egg shells are typically a waste needing disposal,
and in some cases both the inedible eggs and the liquid egg remaining in
the shell are also wasted. Disposal of these wastes to a municipal sewer-
is occassionally practiced, but land disposal is usually the most economical
means. Rainfall on the waste material dissolves large amounts of Biochemi-
cal Oxygen Demanding materials and the runoff can cause serious damage to
the local water resources.
The analytical data on the chemical composition of egg breaking plant
wastes was reported by Walton et a_K (1). This work demonstrated that
there were significant levels of calcium and protein present. The nutri-
tional value of egg shell meal (ESM), when fed to laying hens, was compar-
able to the nutrients that were replaced from feedstuffs normally used in
laying ditets (Vandepopuliere ejt aj_. (2)). With the advent of larger egg
breaking plants, the waste produced at a given location has increased
making it economically feasible to utilize processing equipment that is
currently available.
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SECTION II
CONCLUSIONS
1. Centrifuged egg breaking plant wastes can be processed by a rotary drum
dehydrator such as the Hell SD 45-12.
2. Non-centrifuged egg breaking plant waste can be processed 1f it is
blended with ESM prior to introducing it into the dehydrator.
3. ESM as it is discharged from the dehydrator at 82°C, has excellent
handling and storing properties.
4. The performance of ESM as a feedstuff in cage layers diets is excellent.
5. The economic ratio of processing cost vs_ feedstuff value is highly
favorable to disposing of this waste through the feed milling industry.
6. Egg shell waste from one (1) 30 dozen case, which has been centrifuged,
and dried has an average BODs of 42,545 mg 02. Approximately 50% of
this BODc is readily soluble in water and if spread on a pasture would
be dissolved by rain.
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SECTION III
RECOMMENDATIONS
1. If there is a profitable market for the liquid Inedible egg, install a
centrifuge on stream ahead of the dehydrator.
2. Provide a bypass arrangement to collect egg shell waste in the event
that a dehydrator failure occurs.
3. Provide heavy wear plates in bends and elbows which must handle ESM.
4. Install a secondary collector or wash system to eliminate fine ESM
particle emission.
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SECTION IV
PLAN OF RESEARCH
In the Initial phase it was necessary to select the processing equip-
ment that would dehydrate egg breaking plant wastes to produce ESM. The
dehydrating equipment would be required to accept a wet abrasive product
that could congeal and have the consistency of a glue when the protein was
dehydrated or denatured.
Three commercial co-operators were required to conduct the experiment:
(1) Kraft's egg breaking plant at Neosho, Missouri was selected in which
to install the dehydrator, (2) a feed manufacture, MoArk, Neosho, Missouri,
to mill the feed containing the ESM, and (3) an egg producer, MoArk, Neosho,
Missouri, to conduct the feeding study. The ESM produced must be analyzed
for protein, calcium, phosphorus, fat and microbial content. The nutrition-
al value of ESM would have to be evaluated in layer diets by replacing
nutrients in the control diet with the nutrients in the ESM. The BOD and
COD characteristics of ESM would be needed to evaluate the environmental
benefits in eliminating disposal of this waste material.
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SECTION V
DEHYDRATOR CONSTRUCTION
SELECTION AND INSTALLATION OF EQUIPMENT
Processing and dehydration of egg breaking plant waste can be
accomplished by heating and removing moisture. There are several types of
cookers and dehydrators on the market. Some employ.a batch principle while
others have a continuous flow through a series of shaker screens, tubes or
rotating drums. They are heated with steam, gas or oil. Dehydrators were
available in various sizes, however, the smallest units have more capacity
than needed at most egg breaking plants. Additional constraints on the
selection of the unit were processing controls and costs. A used Heil SO
45-12, Heil Co., Milwaukee, Wise. 53201, was purchased. The capacity of
this dryer is 455 kg H20/hr which is 80% more than needed at the Kraft
plant. The unit consisted of a triple pass rotary dehydrator with controls
to automatically modulate the natural gas burner to regulate the discharge
temperature of the product. The dryer'is the smallest one made by Heil and
sell new for approximately $45,000. A cyclone collector was included with
the dehydrator.
Engineering planning and design, including the development of some
special equipment, was necessary to set up operations. Since the plant was
operating, it was important to have a diverter system so that wastes could
go to the previous disposal carrier or to the dehydrator. This allowed
modification in design and operation without disrupting the egg processing
operations.
The Heil SD 45-12 was transported on a flat bed trailer to the
University of Missouri, Columbia, Missouri. The unit was rewired electri-
cally and a new control panel installed. The dehydrator was cleaned and
painted.
Simultaneously with the dehydrator refurbishing, a structure was
designed and built to house the raw waste or egg shell meal truck. The
shelter was of concrete and steel construction with adequate strength to
support the cyclone collector on the roof.
The dehydrator was unloaded on site with a crane and rolled on pipes
into an existing structure. It was then mounted on appropriate piers.
Steel iSgs to support the cyclone collector were constructed to conform
to the slope of the roof. The collector was positioned to permit gravity
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flow of ESM to the carrier truck or to the dehydrator for recycling. The
diverter pipes were installed at a minimum of 40° to permit the flow of
ESM. Figures 1, 2, 3 and 4 illustrate many of these features.
Special sheet metal design was necessary to connect the dehydrator to
the collector. The 90 turn (Figure #5) is subjected to the continuous
abrasive action of ESM impinging on the curved inner surface. Plate steel,
1/4" thick, was fabricated in the wear area. This heavy elbow and related
duct work were supported by an appropriate steel pipe frame. The radius
of curvature for this elbow is 2 ft.
UTILITIES
The dehydrator was connected to the existing natural gas source, how-
ever, a separate gas meter was installed to provide operating data.
Electricity was provided through a new control panel (Figure #6). The
panel contained the following features:
a. on-off switch
b. temperature controls - No. 522 B solid state temperature control
system. Exhaust product temperature is used to control the flow of
fuel to the furnace.
c. flame control - failure protection switch
d. exhaust fan draft failure shut down switch
e. furnace temperature pyrometer
A special steam line was installed to flood the dehydrating chamber in
case of fire.
A 45° diverter was installed above the dehydrator to direct raw wastes
to the disposal truck or to the blending auger which fed the dehydrator.
OPERATIONAL EXPERIENCE
During the first few days of operation all wastes from the egg break-
ing plant were introduced into the dehydrator. The egg shell waste from
the breaking machines contained 30 percent moisture which included consider-
able free albumen. In addition, the inedible whole eggs were introduced
periodically into the dehydrator. Predictably, the liquid coagulated,
adhered to the dehydrator flights, and clogged the unit. Three design
changes were made:
1. A centrifuge was installed in line to receive the egg shell waste
from the breaking machines. The centrifuge extracted the liquid egg
from the egg shell waste (Figure #10).
2. Since the centrifuge that was available did not have sufficient
capacity to handle both the egg breaker waste and inedible eggs, an
inedible egg separator was designed and constructed so that the
liquid from the inedible eggs could be salvaged separately (Figure
#7). Subsequent to the initial installation a larger centrifuge
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Figure 1. Dehydrator being unloaded
at Kraft Plant in Neosho, Mo.
Figure 2. Dehydrator being placed
in position.
Figure 3. Cyclone installation.
Figure 4. Processed egg shell meal
diverter.
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1. TRANSITION TO BE MADE OF
16 GAGE GALV.
2. BOTTOM & SIDE PIECES TO
BE MADE OF 16 GAGE GALV.
3. TOP SURFACE SUBJECT TO
SEVERE WEAR. USE 6 GAGE
H. R. STEEL.
Figure 5. Special 90 elbow for ESM dehydrator.
8
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Figure 6. Control panel for Heil
dehydrator.
Figure 7. Inedible egg liquid
separator.
Figure 8. ESM blend-back control
gate.
Figure 9.
system.
ESM blending-conveying
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2. (continued)
became available which was capable of handling all of the liquid
that was in the egg breaker waste and inedible eggs.
3. A system for blending dried ESM into the wet shell waste was develop-
ed to eliminate the free albumen by lowering the moisture content.
ESM for use in the blending operation was diverted from the collector
to a surge bin that fed by gravity to the feed auger. The flow of
ESM from the surge bin was controlled by a manual gate at the end of
the discharge tube (Figure #8). Blending was accomplished in the
dehydrator feeding auger. The complete ESM blending system is shown
in Figure #9.
This control of the liquid content of the waste and the blending of dry
ESM with wet shell waste eliminated product sticking within the dehydrator.
Larger quantities of liquid could be introduced into the dehydrator than
were permitted in this study, however a more efficient blender would have
to be installed to handle the blending load. Figure #11 is a diagram
showing the product flow in the breaking plant during this study.
The ESM was a granular type of free flowing product as it came from
the dehydrator. No additional grinding or processing was required before
it's utilization as a feedstuff. This product is shown in Figure #12.
10
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lcTl:i(l ?///>. i V-'U'tt'i H
Figure 10. Egg shell waste centrifuge by Seymour.
11
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BULK EGGS
i
GRADINGJ—
EGG BREAKER
1 - , 1
-EDIBLE FRACTION
SHELL WASTE
INEDIBLE
SEPARATOR
i
-LIQUID—
CENTRIFUGE
INEDIBLE
FRACTION
SPUN SHELL
1
DEHYDRATOR
WET SHELL DISPOSAL
(OPTIONAL)
EGG SHELL MEAL
Figure 11. Flow diagram of egg breaking plant and egg
shell waste processing.
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Figure 12. Granular ESM flowing from the cyclone
collector.
13
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SECTION VI
EXPERIMENTAL PROCEDURE
FEEDING STUDY
A local Integrated egg producing corporation (Including a feed mill)
agreed to place approximately half of their laying hens on a diet formula-
ted with ESM. The control (A) and experimental ESM diet (B) are shown 1n
Table 1.
TABLE 1. DIETS USED IN FIELD STUDIES EVALUATING ESM
Ingredient
Corn, yellow
Milo
Soybean meal (44)*
Dehydrated alfalfa (17)*
Limestone, ground
Egg shell meal
Protein concentrate
Total
Diet Cost $/100 kg
Cost
($/100 kg)
11.37
10.27
15.16
12.76
1.65
3.40
20.68
Composition I
A
25.8
35.0
18.8
3.2
7.2
10.0
100.0
11.97
[%)
B
23.0
38.7
17.6
3.2
7.5
10.1
100.0
12.06
Figures 1n parenthesis represent % protein.
The ESM diet contained approximately 1% more energy than the control
diet. This higher energy level was worth approximately $0.66 per metric
ton. This increased value would negate the slightly higher cost of the
ESM diet.
The number of hens Involved in each treatment (Diet A and Diet B)
ranged between 97,000 to 197,800 over a seven months period.
14
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DATA COLLECTION
Daily processing data were recorded for gas and electricity. In
addition the number of 30 dozen cases broken and plant yield of edible egg
were tabulated.
Egg production and feed efficiency on the feeding trial were computed
monthly.
Analytical work on ESM was conducted on a series of daily production
samples taken during the early phase of the operation. Protein and calcium
was determined according to the AOAC (1970) (3). Amino acid analyses were
done by cation-exchange chromatography (Benson et al_., 1971) (4).
Salmonella and total aerobic counts were determTned. Salmonella Survival
Test was run according to Cotterill and Glauert (1969) (5). The total
aerobic count was determined by weighing 25 g ESM aseptically and blending
it with 225 ml sterile distilled water in a Waring Blendor for 2 min. at
high speed. Total counts were made from Trypticase soy agar plates incu-
bated at 37°C for 24-48 hrs.
BOD and COD
BOD and COD analyses were performed as described by Standard Methods
(1971) (6). Bacterial seed from the BOD tests were cultured from activated
sludge taken from Columbia's Sewage, Treatment Plant. Results for the BOD
and COD are reported as mg Og per kg of dried waste material.
Samples were assayed to determine the effect of the egg shell waste
on a secondary sewage treatment plant and the potential of dissolving
pollutants by rain and transferring them to nearby surface waters. Ten
(10) grams of dried egg shell material were placed into one liter of
distilled water and mixed slowly with a magnetic stir bar. Three mixing
times were used: 15, 30 and 60 minutes. The mixing was done to simulate
the mixing that may occur in a sewer line prior to reaching the treatment
plant and to determine the total fraction of BOD and COD that would be
dissolved by sewage or repeated rainfall.
After mixing, the solutions were placed into one liter Imhoff cones
and allowed to settle. After one hour of settling, solids were measured
in the cone and a sample of the supernatant was removed from mid-depth in
the cone. These samples were analyzed for BOD, COD and pH.
FORMULATION AND MILLING
The cooperating mill used a protein premix which restricted the
ingredient flexibility in formulating the diet. The diets employed in the
field study are shown in Table 1. The grain portions, soybean meal and
ground limestone were adjusted when ESM was added.
15
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A local feed mill received all of the ESM from the beginning of the
project and Incorporated it into layer diets for use in feeding layer
flocks which the mill operator controlled. The level of ESM in the layer
diet was based on its analytical composition. It replaced all calcium
normally obtained from ground limestone, and its protein component substi-
tuted for an equal amount of protein normally supplied by a combination of
other feed ingredients (basically soybean meal in this instance).
The layer diet containing egg shell meal as a feedstuff was fed to
several production flocks. The regular layer diet used by this producer
was fed to a second group of production flocks as a control. Feed consump-
tion and egg production records were kept. As with many field experiments,
control was not easy; and there was an age difference between birds
receiving the egg shell meal (ESM) diet and those receiving the control
diet.
In a milling operation where there is complete ingredient flexibility,
it is possible to realize additional savings by adjusting the phosphorus
and amino acid levels. A suggested formula change with one group of
ingredients is shown in Table 2. ESM can be used with other ingredients
combinations.
TABLE 2. SUGGESTED FORMULA CHANGE FOR ONE GROUP OF INGREDIENTS
Formula Change
Ingredient (%}
Corn -.05
Soybean meal (48)* -.41
DL-methionine -.01
Dicalcium phosphate -.04
Ground limestone -5.87
Egg shell meal +6.38
a
Figure in parenthesis represents % protein.
16
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SECTION VII
RESULTS AND DISCUSSION
Periodic samples of ESM were collected for analyses. Nutrient
analyses were made so that feed formulation information could be supplied
to the feed processor.
MICROBIOLOGICAL COMPOSITION
During December, 1975 and March, 1976 six samples of ESM were collected
aseptically after dehydration for microbial evaluation. It is of interest
that retention time in the dehydrator is such that all microorganisms are
not killed, however all samples were salmonella negative. Total Aerobic
bacteria of 17.6 x 105 per gram in wet shell waste decreased to 5.6 x 105
per gram in dry product processed at 60°C exhaust temperature and to 70 mi-
croorganisms per gram in dry product processed at 127°C exhaust temperature.
This decrease was logarithmic with increasing temperature (Figure #13).
MOISTURE CONTENT OF ESM
The ESM moisture content was studied at six exhaust temperatures.
The data in Table 3 indicates maximum moisture removal at an exhaust temper-
ature of 82 C. The shell particle and membrane sizes were larger at 60 and
71 C than at higher temperatures. Note the large reduction in moisture
between 71 and 82 C processing.
TABLE 3. MOISTURE LEVEL OF ESM PROCESSED AT VARIOUS TEMPERATURES
Exhaust TemperatureMoisture
60
71
82
93
104
115
4.4
6.1
1.3
1.6
1.8
1.6
17
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PROCESS TEMPERATURE (°C)
149
Figure 13. Destruction of microorganisms in egg
breaking plant waste during dehydration at
various temperatures.
18
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RETENTION TIME IN THE DEHYDRATOR
A food dye was mixed with 6 liters of raw centrifuged shells. These
dyed shells, membranes, and adhering egg white were introduced as a single
marked product into the dehydrator. Discharge samples were collected every
two minutes during the next 32 minutes. These ESM samples were examined
for color intensity by three techniques: (1) Average visual appearance of
the dry product based on 12 judges opinions on a 1-5 score basis (5 = most
color). (2) Five g of shell were mixed with 10 ml of water in a test tube,
shaken, let settle, and the membrane layer scored as in 1. (3) Same as 2,
except scores were for shell layer. The experiment was repeated at four
operating temperatures 71°, 82°, 93° and 104°C.
The slug of dyed egg shells passed through the dryer in a biphasic
pattern. One fraction had a retention time of about 4-8 minutes and another
was expelled in about 20-24 minutes. Since similar patterns were obtained
for all four process temperatures only results of the 71 C trial are
presented graphically (Figure #14). The membranes and shells appeared to
pass through the dryer at the same rates. There was no readily apparent
difference in particle size. The red dye was more easily viewed than the
blue dye. However, the color intensity of all samples of ESM was faint.
Attempts to extract the color and measure color intensity colorimetrically
were unsuccessful.
CHEMICAL COMPOSITION
Samples were collected of ESM which resulted from egg shell waste
which had passed through a centrifuge prior to drying. Laboratory analyses
of these samples for protein, calcium and ami no acids appear reasonably
consistent from day to day (Table 4). A protein level of 6.5 percent and
36.3 percent calcium levels were in agreement with previous work on ESM
(Walton et^al-j 1973) (1). The amino acid values are in Table 5 and were
used in computing the cage layer diet.
TABLE 4. ANALYSES OF 15 PRODUCTION SAMPLES OF EGG SHELL MEAL
(Dry Basis)
Centrifuged
%
Protein 6.46 + 0.16
Ether extract 0.47 + 0.18
Calcium 36.30 + 0.65
Phosphorus 0.11+0.01
*
Standard error of the mean.
19
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ro
o
3
84
V)
UJ
ct:
0
o
<
Z) ..
*2 o
> d
o
A A
DRY SHELLS AND MEMBRANES
WET MEMBRANE LAYER
WET SHELL LAYER
EXHAUST TEMPERATURE 7I°C(I60°F)
8
28
12 16 20 24
RETENTION TIMEtMIN.)
Figure 14. Visual color scores for ESM after various retention times,
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TABLE 5. AVERAGE AMI NO ACID COMPOSITION OF 15 SAMPLES OF ESM
Aspartic acid
Threonine
Serine
Glutamic acid
Proline
Glycine
Alanine
Cystine (includes Cysteine)
Valine
Methionine
Isoleucine
Leucine
Tyroslne
Phenylalanine
Histidine
Lysine
Arginine
Total
.58
.32
.39
.82
.43
.37
.29
.33
.40
.22
.24
.42
.18
.21
.24
.30
.43
6.17
*
+ 0.08
+ 0.04
+ 0.05
+ 0.11
+ 0.07
+ 0.05
+ 0.03
+ 0.08
+ 0.06
+ 0.04
+ 0.03
+ 0.06
+ 0.02
+ 0.03
+ 0.03
+ 0.04
+ 0.06
Standard error of the mean.
BOD AND COD OF ESM
Results of the BOD5 and COD tests on the dried egg shell are presented
in Table 6. The wet waste had been centrifuged prior to drying with the
result that most of the BOD5 observed is probably coming from the membrane
attached to the shell. The average COD/BOD ratio of 1.50 suggests that the
organic fraction of the waste is quite biodegradable compared to domestic
sewage (average ratio of 2.0).
21
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Figure 15 represents a 26-day BOD curve for one of the samples repre-
sented in Table 6. A value for the rate constant, k, of 0.19 day'l was
calculated by the Thomas Method (Metcalf and Eddy, 1972) (7) and compares
favorably with a value of 0.17 commonly used as an average value for
domestic sewage (Sawyer and McCarty, 1967) (8). The oxygen demand curve
(Figure #15) shows 68% of the 26-day ultimate BOD was exerted in 5 days.
Results of the mixing-Imhoff cone experiments are presented in Table
7. Mixing time appeared to have a minor influence on soluble BODs or COD.
A 7% increase in both BODs and COD was achieved by increasing the mixing
time from 15 to 60 minutes. Comparing the data of Table 6 and 7, 43-50%
of the BOD5 was solubilized (61-67% of COD). Settling in the cones occurred
very rapidly due to the heavy nature of the egg shells.
BOD5, mg/kg
COD, mg/kg
COD/BOD5
TABLE 6.
Number
Samples
15
15
15
EGG SHELL WASTE CHARACTERISTICS
Mean, X
24,051
35,410
1.50
Range
14,901-32,858
25,577-48,596
1.16-1.72
Std.
Dev., S
+5,024
+5,500
+ 0.17
Material has been centrifuged in a Seymour Shell Spin and dried at 82°C in
a Heil SD 45-12 dehydrator prior to analysis.
TABLE 7. CHARACTERISTICS OF IMHOFF CONE SUPERNATANT
PH
15
Settleable solids*, ml /I
COD,
BOD5
mg/kg
, mg/kg
8
12
Mixing
.36
.8
21,500
10,300
Time,
30
minutes
7,80
13.9
22,800
10,600
60
1
7.
2.
82
5
23,600
12,100
*
10 grams of egg shell waste/liter
Egg shell waste which has been centrifuged and dried exerts an average
BODs of 24,000 mg 02 per kg waste (dry wt.) which is equivalent to 42,545
mg of oxygen demand from each 30 dozen case of eggs processed. Approxi-
mately 50% of this BOD becomes soluble when the dry material is placed in
water. Considering the industries potential of 45,455 metric tons per year
of dry ESM, the readily soluble component could exert a BODg of 545,460 kg
22
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ro
CO
10 15 20
INCUBATION TIME (DAYS)
25
Figure 15. BOD content of one sample of ESM after various
incubation times.
-------
02 per year. The most likely environmental Impact of present disposal
practices for egg shell waste 1s transfer of the BOD to surface waters by
rainfall runoff. This is because this waste material is presently disposed
of on land rather and not converted into a by-product (ESM). However, egg
shell waste discharged to a sewer would exert a significant BOD load on the
receiving secondary treatment plant.
PLANT PRODUCTION
The average monthly egg breaking plant data are shown in Table 8. The
average number of cases broken daily varied slightly with March being the
highest with 1,395 cases and June the lowest with 1,264 cases. The average
pounds of edible egg and ESM varied with the number of cases broken. From
these data an egg breaker with a centrifuge could expect 1.77 kg ESM from
each 30 dozen cases broken.
TABLE 8. AVERAGE DAILY PRODUCTION AT EGG BREAKING PLANT UNDER STUDY
Month
March
April
May
June
July
August
September
30 doz
cases
1,395
1,370
1,338
1,264
1,330
1,363
1,318
Edible egg
kg
25,069
24,649
23,102
20,970
23,242
22,153
22,149
ESM
kg
2,443
2,606
2,409
2,100
2,304
2,384
2,202
CAGE LAYER PERFORMANCE
When the feeding trial was initiated the flocks were allotted to the
treatments according to age. Initially the bird age was similar on both
treatments however as the experiment progressed it was not possible to
maintain the desired balance (Table 9).
Laying hens reach peak production at approximately 32 weeks of age.
Subsequent to peak production there is a linear decrease in egg production
and a corresponding increase in feed required to produce a dozen eggs.
Using the average age difference of 11.6 weeks, a change in egg
production and feed conversion of 4.4% and 0.18 kg feed/doz. eggs respec-
tively can be predicted (Scott £t al_., 1969) (9). This negates the
24
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TABLE 9. PERFORMANCE DATA OF CAGE LAYERS FED ESM AND NUMBER OF LAYERS INVOLVED
ro
ui
Age (weeks)
March
April
May
June
July
August
September
AVERAGE
Control
48.9
54.5
58.7
55.6
59.6
61.3
62.3
57.3
ESM
46.4
43.5
44.6
44.0
46.2
45.7
49.7
45.7
Egg
Production (%}
Control
79.0 .
75.6
72.3
76.0
70.6
68.8
68.7
73.0
ESM
77.8
79.9
76.4
77.5
79.6
79.4,
77.1
78.2
Feed conversion
(kg/doz)
Control
1.72
1.81
1.77
1.76
1.79
1.82
1.87
1.79
ESM
1.65
1.73
1.71
1.59
1.57
1.60
1.68
1.65
Number of
hens (000 omitted)
Control
164.0
164.0
184.0
166.5
133.0
104.0
97.0
144.6
ESM
109.4
162.4
197.8
183.8
193.6
159.6
159.6
166.6
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observed improvement in egg production and feed conversion when ESM was
fed. Performance on both diets was comparable.
Since the experiment has been terminated the processor and feed manu-
facturer-egg producer has signed a two year contract on ESM. The continued
use of ESM attests to the satisfaction of both parties on its' economic
value.
26
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SECTION VIII
ECONOMIC CONSIDERATIONS
A series of tables were developed describing the production cost of
ESM under a variety of equipment and labor cost situations (Appendix I).
The calculated production cost of ESM ranges from $13.58 to $39.82 per
metric ton with cost per ton decreasing with increasing size of the egg
breaking operation.
BASIS FOR COOPERATORS-SHARE OF ESM VALUE
The value of ESM as a feedstuff was accepted as a basis for the
economic relationship between the cooperators. ESM was assigned a value
based upon the market value of the ground limestone and the protein ingred-
ients it replaced in a ration. At the time the experiment was initiated
it had a value of $34 per metric ton. Hence, this $34 was available to
pay processing costs and provide payments to the cooperators. The process-
ing plant operator delivered the dry product to the mill. The mill operator
paid the processor for his out-of-pocket costs plus one-third of the remain-
ing value of the product. The other two-thirds of the remaining value was
shared equally by the miller and the egg producer (the same person in this
case).
OWNERSHIP AND OPERATING COSTS
The overall economic potential for an egg shell waste processing
system mainly depend on the size of equipment and plant. The minimum
dehydrator installation cost would be approximately $35,000 (1977 prices).
Daily ownership cost would also vary depending on depreciation, interest,
maintenance, insurance and taxes. The basis for cost in this study are
presented in Table 10 and ranged between $15.87 and $25.20 per day depend-
ing upon the length of depreciation.
TABLE 10. COST OF DEHYDRATOR OWNERSHIP BASED ON AN INSTALLED COST OF
$35,000
Depreciation period =
Cost item 10 year 20 year 30 year
Annual depreciation
Annual interest
(8% of avg. invested)
$3,500.00
$1 ,400.00
$1,750.00
$1,400.00
$1,166.67
$1,400.00
Continued
27
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TABLE 10 (continued)
Depreciation period
Cost item 10 year 20 year 30 year
Maintenance and repair
(2% of cost, annually) $ 700.00 $ 700.00 $ 700.00
Insurance and taxes
(2% of cost, annually) $ 700.00 $ 700.00 $ 700.00
Annual cost of ownership $6,300.00 $4,550.00 $3,966.67
Cost/day of operation
(250 days/yr.) $ 25.20 $ 18.20 $ 15.87
Operating costs to produce one ton of dried egg shell meal was calcula-
ted for the Missouri field installation by using records of labor input and
energy use. An average of 2.38 metric tons of dried egg shell meal was
produced each day with a dally input of 57.7 KWH of electricity, 139 cubic
meters gas and one hour of labor. The cost of these inputs were 2.7^/KWH
of electricity $1.00/28 M3 of gas, and $6.00/hr. of labor. Hence, the cost
of producing one metric ton of ESM was estimated by combining ownership and
operating expenses. It ranged from $15.82/metric ton to $11.92/metric ton
depending upon the depreciation schedule followed (Table 11).
TABLE 11. COST TO PROCESS ONE METRIC TON OF DRIED EGG SHELL MEAL BASED UPON
ACTUAL OPERATING COSTS (MISSOURI FIELD INSTALLATION) COMBINED
WITH DRYER OWNERSHIP COSTS
Depreciation period
Cost item 10 year 20 year 30 year
Dehydrator ownership $10.58 $ 7.64 $ 6.67
Labor
(1 hr./day 0 6.00) $ 2.52 $ 2.52 $ 2.52
Electricity
(57.7 KWH/day) $ .65 $ .65 $ .65
Gas
(139 M3/day) $ 2.07 $ 2.07 $ 2.07
Total cost ton ($/metric ton) $15.82 $12.88 $11.91
28
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VALUE OF EGG SHELL MEAN
The feedstuff value of ESM was estimated over a wide range of corn and
soybean meal prices, as identified in Table 12. For example, if corn and
soybean meal prices increased to $92 and $210 respectively, ESM would be
worth $37.75 per ton.
TABLE 12. VALUE OF CENTRIFUGED ESM BASED ON VARIOUS CORN-SOYBEAN PRICES
Corn
SBM (48)* ($/metric ton)
($/metric ton) 75 85 95 105
150 33.00
160
170
180
190
200
210 — — ** —
220
230
240
250 39.70
115 125
36.10
— —
— —
— —
— —
— —
— —
— —
— —
— —
42.70
*Numbers in parenthesis represent % protein.
**ESM value of $37.75 based on prices for corn (@$92) and SBM (@$210).
Comparing this $37.50/metrie ton value for the ESM with the cost figures
in the Appendix (Tables A-5), it can be seen that the process is economically
justified except for small operations of 1000 cases/day or less which also
have a high labor cost of $5.00/hour or more. This comparison does not in-
clude elimination of the pollution control cost for disposal of this waste
with its high BOD levels. Accounting for the disposal costs further increases
economic feasibility of this by-product recovery system.
29
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SECTION IX
FEED CONTROL OFFICIAL DEFINITION
In April 1975 a product description was submitted for consideration by
the Board of Directors of the Feed Control Officials. This description
read as follows, "Egg Shell Meal is a mixture of egg shells, shell membranes
and egg content obtained by drying the residue from an egg breaking plant in
a dehydrator to an end product temperature of 200 F. It must be designated
according to its protein content." In order to describe and control the
product, minimum protein and calcium levels for the non-centrifuged product
should be 7 percent and 35.5 percent respectively. While the minimum
protein and calcium on the centrifuged ESM would be 5.0 and 35.5 percent,
respectively.
In June 1976, after reviewing moisture, salmonella and bacteriological
data it was recommended that the end product temperature be reduced from
200 F to 180 F. With this recommended modification, ESM remained on a
tentative status.
30
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REFERENCES
1. Walton, H. V., 0. J. Cotter-ill and J. M. Vandepopuliere. 1973.
Composition of shell waste from egg breaking plants. Poultry Science
52: 1836-1841.
2. Vandepopuliere, J. M., H. V. Walton and 0. J. Cotterill. 1975.
Nutritional value of egg shell meal. Poultry Science 54: 131-135.
3. Association of Official Analytical Chemistry. 1970. Methods of
Analysis of the Association of Official Analytical Chemists, llth
edition. Page 123 and 132.
4. Benson, J. V., Jr. and J. A. Patterson. 1971. New Techniques in
Ami no Acid, Peptide, and Protein Analysis, Editors—A. Niederweiser
and G. Pataki, Ann Arbor Science Publishers, Ann Arbor, Michigan
pp. 1-67.
5. Cotterill, 0. J. and J. Glauert. 1969. Thermal resistance of
Salmonellae in egg yolk products,containing sugar or salt. Poultry
Science 48: 1156-1166.
6. American Public Health Association. 1971. Standard Methods for
Examination of Water and Wastewater. Washington, D. C. Page 489-499.
7. Metcalf and Eddy, Inc. 1972. Wastewater Engineering, Collection,
Treatment, Disposal. McGraw-Hill Book Co., New York, N. Y. Page
248-249.
8. Sawyer, C. N. and P. L. McCarty. 1967. Chemistry for Sanitary
Engineers. McGraw-Hill Book Co., New York, N. Y. Page 405.
9. Scott, M. L., M. C. Nesheim and R. J. Young. 1969. Nutrition of the
Chicken. M. L. Scott and Associates, publishers, Ithaca, New York
14850. Page 80.
31
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APPENDIX A
AN ECONOMIC ANALYSIS OF THE DEHYDRATION OF EGG BREAKING PLANT WASTES
(November, 1974)
TABLE A-1. DRYER COST
Assumed First Cost ($)
Cost Item
Annual depreciation
(30-year life)
Annual Interest
(8% of avg. invested)
Maintenance and repair
(2% of cost, annually)
Insurance and taxes
(2% of cost, annually)
Annual cost of ownershl p
Cost/day of operation
(250 days/hr)
Cost/day of operation
(156 days/yr)
' - ,. ! ' . . ,.'.•''-.
25,000 30
$ 833.33 $ 1
1,000.00 1
500.00
500.00
2,833.33 3
11.33
18.16
,000
,000.00
,200.00
600.00
600.00
,400.00
13.60
21.79
35,000
$ 1,166.67
1,400.00
700.00
700.00
3,966.67
15.87
25.43
TABLE A-2. LABOR COST
Annual cost
Daily cost
Hourly
3
$6,240 $8
24.00
rate ($)
4
,320
32.00
5
$10,400
40.00
32
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TABLE A-3. DAILY MOISTURE LOAD, FUEL COST, AND DRY MATTER YIELD
(EGG BREAKING PLANT WASTE)
Size of operation (cases
Item
Kg wet waste
Kg water @ 30%
Cal required
Liter fuel
Fuel cost 0 7.9£/L
Kg dry material
Metric tons dry mat.
1,000
2,273
682
76 x 107
95
$7.50
1,591
1.59
1,500
3,409
1,023
113 x 107
142
$11.22
2,386
2.39
2,000
4,545
1,364
151 x 107
189
$14.93
3,182
3.18
per day)
2,500
5,682
1,705
189 x 107
237
$18.72
3,977
3.98
Note assumptions: 8 x 10 cal/1 fuel, used at 50% efficiency (i.e., 1.1 x
evaporates 1 kg water)
TABLE A-4. COST $ PER DAY FOR DRYING EGG BREAKING PLANT WASTES
Dryer cost
$
25,000
30,000
35,000
Labor cost
#/hr
3
4
5
3
4
5
3
4
5
1,000
42.83
50.83
58.83
45.10
53.10
61.10
47.37
55.37
63.37
Size pf_
1,500
46.58
54.58
62.58
48.85
56.85
64.85
51.11
59.11
67.11
operation leases
2,000
50.33
58.33
66.33
52.60
60.60
68.60
54.87
62.87
70.87
per day)
2,500
54.08
62.08
70.08
56.35
64.35
72.35
58.62
66.62
74.62
33
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TABLE A-5. COST $ PER METRIC TON FOR DRYING EGG BREAKING PLANT WASTES
Dryer cost
$
25,000
30,000
35,000
Labor cost
#/hr
3
4
5
3
4
5
3
4
5
1,000
26.92
31.96
36.97
28.35
33.37
38.40
29.77
34.80
39.83
Size of operation
1,500
19.48
22.82
26.17
20.43
23.78
27.13
21.37
24.73
28.07
(cases/day)
2,000
15.82
18.34
20.84
16.53
19.04
21.56
17.25
19.76
22.28
2,500
13.58
15.59
17.60
14.16
16.16
18.17
14.72
16.73
18.74
34
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APPENDIX B
OPERATING PROCEDURE
START UP PROCEDURE
1. Turn on automatic trunion and drive chain oiler
2. Grease trunion and other grease fittings, do not grease motors.
3. Turn main power switch on.
4. Turn control panel power switch on.
5. Set dial reading on 520 controller to get needle on positive (+) side
of dial.
6. Check gas modulator valve for being closed in #1 position.
7. Turn main drive switch on.
8. Turn gas blower switch on.
9. Depress pilot light-off button after safe start buzzer (green signal
light) comes on. Pilot should light, when solenoid energizes (loud
snap), release light-off button. Pilot should remain lit.
10. Open main gas valve.
11. Open two gas control valves by pushing levers forward.
12. Increase reading on 520 controller dial until needle is on negative
(-) side of dial (5-10 ).. As needle moves to positive side, increase
dial setting gradually (5-10 ), and allow burner to bring heat up.Q
Continue raising dial setting gradually until desired reading (180 )
is reached.
13. Turn feeder conveyor on to allow machine to receive waste shells.
35
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SHUT DOWN PROCEDURE
1. Clear and turn feed conveyor off
2. Turn main gas valve off.
3. Turn two lever controlled gas valves off by moving levers to the rear
or off position.
4. Turn gas blower switch off.
5. Turn main drive switch off.
6. Set dial on 520 controller to zero (000) to allow gas modulator valve
to close.
7. Turn control panel power off.
8. Turn main power switch off.
9. Cover solenoids and valves on east end of machine with plastic to
protect from water from clean-up crew.
36
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-78-CM
2.
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
ELIMINATION OF POLLUTANTS BY UTILIZATION OF EGG
BREAKING PLANT SHELL-WASTE
5. REPORT DATE
March 1978 issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
JJ" M.S Vandepopuliere, H. V. Walton, W. Jaynes,
0. J. Cotterill
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
University of Missouri
Columbia, Missouri 65201
10. PROGRAM ELEMENT NO.
1BB610
11. CONTRACT/GRANT NO.
S-803614
12. SPONSORING AGENCY NAME AND ADDRESS
Industrial Environmental Research Lab-Gin., Ohio
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA/600/12
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Egg breaking plants yield an estimated 50,000 tons of waste annually.
These wastes are commonly disposed of on land. This method of disposal is
becoming more difficult due to the potential for pollution of local water
resources.
/
A triple pass rotary drum dehydrator was installed at an egg breaking
plant. With appropriate engineering modifications a system for producing
egg shell meal from the total egg shell waste from the breaking plant was
developed. This meal was utilized as a feedstuff by a local mill and incor-
porated into a layer diet. This diet was fed to several commercial flocks
of cage layers.
Appropriate data were collected to determine meal production costs,
yield of meal, feed produced, feeding data, and layer flock performance.
COD and BOD data were generated to determine the pollution potential of the
waste were it not converted to a useful by-product.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COS AT I Field/Group
Poultry, Pollutants, Waste Disposal,
By-products
Egg Breaking Wastes,
Pollution Potential,
Egg Shell Meal, By-
product Recovery, Feed
Performance
43F
50B
91A
8. DISTRIBUTION STATEMENT
19. SECURITY CLASS (This Report)
Release to Public
21. NO. Of PAGES
47
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
* U.S. GOVERNMENT PRINTING OFFICE: 1978- 260480:40
37
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