SETOV
United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-81-112 Aug. 1981
Project Summary
Protein Recovery from
Beef Packing Effluent
John C. Ward, Walter Adams, and H. Chr. Isaksen
The wastewater from a large beef
packing plant, containing 3000 mg/l
BOD5 and 2,500 mg/l of suspended
solids was treated in a physiochemical
process that recovers protein. This
process removed 58% of the total
nitrogen, 80% of the oxygen demand
and suspended solids, and 94% of the
fat, oil and grease. The discharge of
BODS was reduced to less than 3
pounds per head of beef slaughtered.
For every pound of BOD5 entering the
wastewater treatment plant, 0.77
pounds of product was recovered with
a composition of 38% protein, 11%
grease and oil, 27% inorganic solids,
and 24% other solids (dry weight
basis). About 2 pounds of protein
were recovered per head. Total cost
was $3 per 1,000 gallons (44% capital
costs). A price of 420 per pound of
protein would pay all costs. The figures
given above were observed in a full
scale plant and should not change
significantly with different size waste-
water treatment plants. This waste-
water treatment process can be used
as a pretreatment process for beef
packing effluent prior to discharge to a
sewage treatment plant.
Seven different beef packing waste-
water treatment processes including
other methods of protein recovery are
discussed and compared in the full
report.
This Project Summary was devel-
oped by EPA's Industrial Environ-
mental Research Laboratory, Cincin-
nati, OH, to announce key findings of
the research project that is fully docu-
mented in a separate report of the
same title (see Project Report ordering
information at back).
Introduction
Beef packing effluents pose a consid-
erable challenge to wastewater treat-
ment technology. Several water quality
parameters are listed below in Table 1
along with their average concentrations
in domestic wastewater and the average
concentrations observed in the effluent
from this beef packing plant.
Clearly the oxygen demand of beef
packing effluent is 20 to 30 times that of
domestic wastewater, so that at least
95% removal would be necessary to
reduce the oxygen demand of beef
packing effluent to that of untreated
domestic wastewater. In addition, the
quantity of suspended solids is over 10
times that of domestic wastewater. As a
final complication, beef packing plants
are not usually operated continuously,
so that conventional biological waste-
water treatment techniques leave a
great deal to be desired.
This lack of continuous operation
indicates the desirability of a physio-
chemical wastewater treatment process.
In addition, it would be highly desirable
if some cost recovery were possible
from the sale of the relatively large
quantities of sludge that can be expected.
The Alwatech process is a physio-
chemical wastewater treatment process
that also recovers protein (from the beef
packing effluent) which can be sold to
partially recover the cost of wastewater
treatment. The process uses sulfuric
acid, H2S04, for pH reduction, calcium
lignosulfonate for protein precipitation.
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Table 1 Comparison of Beef Packing and Domestic Wastewaters
Average Concentration, mg/l
Water Quality Parameter
COD
5-Day, 20°C BOD
Suspended Solids
in
domestic
wastewater
150
140
235
in beef
packing
effluent
4,610
2.940
2,460
and calcium hydroxide, Ca(OH)2, for
both effluent and sludge neutralization.
This report gives the results of a full
scale evaluation of the Alwatech process
installed at a large beef packing plant in
the United States. While the Alwatech
process is not necessarily limited to
treatment of and protein recovery from
beef packing effluents, this report is
based on beef packing effluent treat-
ment and protein recovery. Other efflu-
ents treated by the Alwatech process
include those from poultry and pig
abattoirs.
Unit Waste Production
Table 2 shows the unit waste produc-
tion rates for 6 different waste products.
From this table, it is clear that the
quantities of the last 3 wastes listed are
minor when compared to the quantities
of the first 3 wastes listed. Because the
average live weight of beef killed at this
plant is 1,040±15 pounds, the quantity
of waste produced per 1000 pounds live
weight killed is close to the quantity
produced per head of beef. About 350
gallons of wastewater are produced per
head.
Brief Description of the
System Evaluated
The plant wastewaters, excluding
those from the stock pens and con-
densers, are sent to an existing clarif ier
which was modified to also balance flow
volumes. The pH of the effluent from
this clarifier is reduced with H2S04 to
between 2 and 3. Calcium lignosulfonate
is added to the wastewater in quantities
that are directly proportional to the COD
concentration. Following this protein
precipitation step, the resulting floe
containing protein, fat, and suspended
material is separated in two dissolved
air flotation tanks.
Following this separation, the pH of
the liquid effluent is raised to about 4
with Ca(OH)2 and then mixed with other
wastewater streams that are not treated
by this process. The pH of the resulting
mixture is about 7 and consequently is
suitable for additional treatment by
biological wastewater treatment
processes.
The sludge is also neutralized with
Ca(OH)2 to an initial pH of 9.1 which
eventually drops to a pH of 7.6. The
sludge is dewatered in a centrifuge,
dried and sold.
Table 2. Unit Waste Production
Waste Produced
Conclusions
For a beef packing effluent with an
initial BODS averaging 3,000 mg/l, the
Alwatech process is capable of removing
over 80% of the oxygen demand, about
86% of the suspended solids, and 94%
of the fat, oil, and grease. Average
removals of 41 % of the ammonia N and
63% of the organic N were observed.
The solids concentration of the sludge
produced by this flotation process aver-
ages about 9%.
The optimum calcium lignosulfonate
dose is about 5% of the influent COD
concentration although additional work
may later show that this dose can be
reduced somewhat. While the optimum
pH range varies from about 2 to less
than 3, for incoming COD concentrations
greater than about 1,800 mg/l, it is less
Ib
10*lbLWK*
5-day, 20°C BOD
Total suspended solids
Grease and oil
Organic nitrogen
Ammonia nitrogen
Phosphate
6.51
5.44
1.26
0.28
0.18
0.04
•lb/103 Ib live weight killed
Scope of This Project
The major water quality parameters
used to measure the effectiveness of
this process are (listed in order of
decreasing concentration):
COD
BOD5
Total suspended solids
Total volatile solids
Volatile suspended solids
Grease and oil
Organic nitrogen
Ammonia nitrogen
Phosphate
The data summarized in this report
cover a period of 8 months of operation.
Because both the BOD5 and suspended
solids loadings were 50% greater than
the values used in the initial design, a
certain amount of additional research
and development work was necessary
during this 8 month period. Near the end
of the 8 month data logging interval, 2
perf orma nee tests of 2 weeks each were
conducted. The results obtained during
these 2 trial periods may be a better
indication of the capabilities of this
process than the averages observed
during the 8 month duration of the data
collection summarized in this report.
expensive to use pH values nearer 2
because lower calcium lignosulfonate
doses can be used. While chemical
costs increase as the influent COD con-
centration increases, the rate of increase
is less at oH values near 2.
While the centrifuge efficiency was
about 94% for water, it was only 52% for
total solids, 66% for protein and 21 % for
oil and grease. When the centrifuge
reject solution is recirculated back to the
plant influent, the incoming COD is
increased 32%, the influent suspended
solids are increased 29%, and the
influent grease and oil is increased 36%
to 52%.
Total observed operating costs were
470 per head or $1.68 per 1,000 gallons
of wastewater treated. About 2 pounds
of protein were recovered per head, so
this protein would have to sell for 23.50
per pound in order to cover all operating
costs. However, operating costs could
be reduced to 400 per head by using less
calcium lignosulfonate. Calcium
lignosulfonate accounted for 39% of the
total operating costs followed by 25%
for labor, 15% for hlsSO^ 10% for
Ca(OH)2, 9% for energy (1979), and 2% t
for repairs.
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Biological activity in the clarifier
balancing tank preceding the Alwatech
plant had an influence on oxygen
demand and nitrogen removal efficien-
cies. This biological activity is believed
due to the paunch and gut contents,
relatively long detention time (1.5-2
hours), and high effluent temperatures
(100° to 125°F). However, the detention
time cannot be reduced below 1.5 hours
as fat skimming and bottom sludge
removal would both suffer.
The discharge of 5-day, 20°C BOD
from this beef packing plant has been
reduced to less than 3 pounds per head.
For every pound of 5-day, 20°C BOD
entering the Alwatech plant, an average
of 0.77 pounds of product was recovered
with an average composition of 38%
protein, 11% grease and oil, 27% fixed
solids, and 24% other solids on a dry
weight basis.
Monthly Average Effluent
Concentrations
The monthly average effluent con-
centrations were 806± 413 mg/l BOD,
46± 24 mg/l organic nitrogen, 41 ± 13
mg/l ammonia nitrogen, and 15 ± 11
ng/l phosphate where the first figure is
the average (arithmetic mean) and the
second figure is the arithmetic standard
deviation. Both the grease and oil and
the total suspended solids effluent
concentrations were so variable (coef-
ficient of variation >1) that they were
better represented by a tog normal
(geometric) frequency distribution.
Accordingly, the suspended solids ef-
fluent concentration geometric mean
was 309 mg/l with a geometric mean
standard deviation of 2.2. The grease
and oil effluent concentration geometric
mean was 40 mg/l with a geometric
standard deviation of 4.8.
Ammonia and Organic Nitrogen
The ratio of the standard deviation/
mean for both the influent ammonia and
organic nitrogen concentrations was
the same (0.48). The total nitrogen
concentration averaged 210 mg/l with
a standard deviation of 74 mg/l giving a
standard deviation/mean ratio of 0.35
which indicates that the total influent
nitrogen concentration was less variable.
The average removal of total nitrogen
was 58% with a standard deviation of
21% giving a standard deviation/mean
ratio of 0.36 which indicates that the %
removal of total nitrogen was also less
I variable. Total nitrogen = ammonia +
organic nitrogen because it is assumed
that nitrate plus nitrite nitrogen is
negligible in comparison in this waste-
water.
On the average,41% of the influent
ammonia nitrogen concentration of 82
mg/l was removed and 63% of the
influent organic nitrogen concentration
of 128 mg/l was removed. Consequently,
the ammonia and organic nitrogen con-
centrations in the effluent were both
about 48 mg/l each so that the nitrogen
effluent concentration was 95 mg/l.
An equation developed during the
course of a laboratory investigation of
protein recovery using chitosan was
modified so that the % removal of organic
nitrogen could be predicted as a func-
tion of temperature, pH, calcium ligno-
sulfonate dose, and the COD concentra-
tion in the wastewater influent. Com-
parison of the % organic nitrogen re-
movals calculated by this equation with
the observed data gave a correlation
coefficient of 0.84. Percent COD remov-
al and % organic nitrogen removal are
linearly related with a correlation coeffi-
cient of 0.82.
Phosphate and Fecal Coliforms
The average rempval of phosphate
was 49% which reduced the average
influent concentration of 17 mg/l P to 9
mg/l P. A concentration of 6,600 fecal
coliforms per 100 ml were observed in
the effluent.
Solids
Bottom sludge from the air flotation
tanks is 28% of the total wet sludge
volume produced. Total dried sludge
production averaged 5 pounds per
1,000 pounds live weight killed. The
dried sludge was 38% protein, 27%
inorganic solids, 11% grease and oil,
and 24%other. The solids concentration
of the dried sludge was 88% and there-
fore the water concentration was 12%.
The dried sludge is sold for use in animal
feeds.
Material Balances of Pollutants
On the average, 27.5 gallons of wet
sludge were produced per 1,000 gallons
of wastewater treated. Ninety percent of
the wet sludge becomes centrifuge
reject solution and 10% becomes de-
watered sludge. The concentrations of
COD, grease and oil, and suspended
solids in the centrifuge reject solution
averaged 50,000 mg/l, 5,860 mg/l, and
21,000 mg/l, respectively. Consequently,
pumping the centrifuge reject solution
back into the plant influent increased
the incoming COD 32%. Eighty-three
percent of the incoming COD is removed,
and of the amount removed, 62% winds
up in the dewatered sludge and the
remaining 38% leaves in the centrifuge
reject solution.
Based on separate disposal of the
centrifuge reject solution, 81% of the
suspended solids is removed, and of the
amount removed, 64% winds up in the
dewatered sludge and the remaining
36% leaves in the centrifuge reject
solution. Consequently, pumping the
centrifuge reject solution back into the
plant influent would increase the influ-
ent suspended solids 29%.
Again based on separate disposal of
the centrifuge reject solution, 94% of
the grease and oil is removed, and of the
amount removed, 53% winds up in the
dewatered sludge and the remaining
47% leaves in the centrifuge reject
solution. The grease and oil concentra-
tion in the dewatered sludge is about
6%. Recirculation of the centrifuge
reject solution back to the plant influent
would increase the influent grease and
oil by roughly 44%.
Filter Belts
Initially it was attempted to dewater
the wet sludge using filter belts, but
these were found to perform unsatisfac-
torily on the wet sludge produced, so
they were replaced with a centrifuge.
Economics
Virtually all cost inputs to the process
were measured including labor, cost of
repairs and maintenance, energy, and
chemicals. Operating costs were $1.68
per thousand gallons treated. The capital
costs for an 800,000 gpd plant are an
additional $1.32 per thousand gallons
treated, so the total cost is $3.00 per
1,000 gallons treated. The capital costs
(and consequently the total costs) include
property taxes, interest recovery of
principal, and insurance. These costs do
not give any credit for the protein
recovered and sold.
About 2 pounds of protein are recovered
per head. The average quantity of waste-
water treated in the Alwatech plant was
276 gallons per head. Therefore the
average cost of treating this wastewater
was 830 per head, so that the protein
recovered would have to sell for about
420 per pound of protein in order to
recover all costs.
The wastewater treatment plant ef-
fluent pH averaged 3.7, but the waste-
water discharged to the sewage treat
0 US GOVERNMENT PRINTING OFFICE: 1981-757-OU/7Z86
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ment plant averaged 7 because of the
effect of mixing the plant effluent with
other wastewater streams from the beef
packing plant. If the Alwatech waste-
water treatment plant effluent had been
raised to pH 7, this would have resulted
in a needless increase of 10% in total
costs.
Recommendations
Means of reducing the operating cost
of the Alwatech process should be
investigated. While the pH should be
near 2 for minimum operating cost, the
calcium lignosulfonate dose need not
exceed 5% of the influent COD concen-
tration. The effect of doses less than 5%
on COD removal, and especially protein
recovery should be studied.
The results of a detailed laboratory
investigation of the use of chitosan are
summarized. A similar study should be
done for calcium lignosulfonate, be-
cause of the potential for significant
reduction in operating costs. In addition,
it is virtually impossible in a full scale
operation (such as the one described in
this report) to evaluate the effect of
various plant operating practices on the
sludge produced. Where protein recovery
and hence financial recovery is possible,
it is essential to know the effect of
changes in operating variables on sludge
production and characteristics.
Ways to increase the centrifuge ef-
ficiency for total solids as well as protein
need to be investigated. The low protein
efficiency (66%) of the centrifuge pre-
cludes separate treatment of the centri-
fuge reject solution unless one is willing
to accept a 34% loss of potentially
recoverable protein.
Before treatment by the Alwatech
process, it may be desirable to have
heavy solids and readily floatable grease
removed by an efficient continuous
screening system followed by a balanc-
ing tank with a relatively short detention
time (30 minutes) to even out rapid
variations in flow and concentration.
This might improve solids handling and
sludge product quality.
While additional investigation of this
process has been recommended, the
process is ready to be used in its present
state of development.
John C. Ward was attending Colorado State University. Fort Collins. CO 80523;
Walter Adams is with Sterling Colorado Bgbt.Company, Sterling, CO 80751;
andH. Chr. Isaksen is Process Department Head of Alwatech, Oslo, Norway. A
Kenneth Dostal and Jack Witherow are the EPA Project Officers (see below). \
The complete report, entitled "Protein Recovery from Beef Packing Effluent,"
(Order No. PB 81-224 362; Cost: $15.50, subject to change) will be available
only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officers can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
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