EPA-600/2-76-224
December 1976
Environmental Protection Technology Series
PROCEEDINGS OF THE
SIXTH NATIONAL SYMPOSIUM ON
FOOD PROCESSING WASTES
Industrial Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45288
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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 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.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-76-224
December 1976
PROCEEDINGS OF THE SIXTH NATIONAL SYMPOSIUM
ON FOOD PROCESSING WASTES -
April 9-11, 1975
Madison, Wisconsin
Co-sponsored by
NATIONAL CANNERS ASSOCIATION
Berkeley, California 94710
and
WISCONSIN CANNERS AND FREEZERS ASSOCIATION
Madison, Wisconsin
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-Ci, Office of Research and Development, US
Environmental Protection Agency, and approved for publication. Approval
does not signify that the contents necessarily reflect the views and
policies of the U.S. Environmental Protection Agency, nor does mention
of trade names or commercial products constitute endorsement 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
(lERL-Ci) assists in developing and demonstrating new and improved
methodologies that will meet these needs both efficiently and
economically.
The Sixth Hational Symposium on Food Processing Wastes was
cosponsored with the National Canners Association and the
Wisconsin Canners and Freezers Association. The primary purpose
of these symposia is the dissemination of the latest research,
development and demonstration information on process modifications,
waste treatment, by-product recovery and water reuse to industry,
consultants and government personnel. Twenty papers are included
in this Proceedings as well as the final registration list.
These symposia will be continued; the Seventh is scheduled for
April 7 to 9, 1976, in Atlanta, Georgia. If you are interested in
participating or wish to receive additional information contact:
Industrial Pollution Control Division
Industrial Environmental Research Laboratory—Ci
Environmental Protection Agency
Cincinnati, Ohio 45268
David G. Stephan
Director
Industrial Environmental Research Laboratory
Cincinnati
111
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CONTENTS
Page
INTRODUCTORY REMARKS 1
Lt. Governor Martin J. Schreiber
INVESTIGATION OF AN ANAEROBIC-AEROBIC LAGOON SYSTEM TREATING
POTATO PROCESSING WASTES
James N. Dornbush, Dwayne A. Rollag, and William J.
Trygstad
UTILIZATION OF CHITOSAN FOR RECOVERY OF COAGULATED BY-
PRODUCTS FROM FOOD PROCESSING WASTES AND TREATMENT SYSTEMS 22
Wayne A. Bough, D. R. Landes, Josephine Miller, C. T.
Young, and T. R. McWhorter
DOUBLE DIP CAUSTIC PEELING OF POTATOES 49
C. C. Huxsoll, M. L. Weaver, and R. P. Graham
EGG BREAKING AND PROCESSING WASTES CONTROL AND TREATMENT 61
W. J. Jewell, W. Siderewicz, R. C. Loehr, R. R. Zall,
0. F. Johndrew, H. R. David, and J. L. Witherow
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PULP RECOVERY FROM TOMATO PEEL RESIDUE 105
W. 6. Schultz, R. P. Graham, and M. R. Hart
PROTEIN PRODUCTION FROM CHEESE WHEY BY FERMENTATION 118
Chu H. Tzeng, Douglas Sisson, and Sheldon Bernstein
TREATMENT CAPABILITIES OF AN EXTENDED AERATION SYSTEM
FOLLOWING ANAEROBIC LAGOONS TREATING MEAT PACKING WASTES 131
W. James Wells, Jr., Paula B. Wells, and Darryl D.
Alleman
A PROGRESS REPORT ON A SYSTEMS APPROACH TO EFFLUENT
ABATEMENT IN HAWAII 151
Richard T. Webb
UTILIZATION OF CHEESE WHEY FOR WINE PRODUCTION 180
Hoya Y. Yang, Floyd W. Bodyfelt, Kay E. Berggren, and
Peter K. Larson
DRY PEELING OF TOMATOES AND PEACHES 194
Traver J. Smith
A FRUIT PROCESSORS WASTE TREATMENT EFFLUENT VARIABILITY AND
PLANNING FOR ATTAINMENT OF 1983 EFFLUENT GUIDELINES 204
Larry A. Esvelt
TOMATO CLEANING AND WATER RECYCLE 223
Walter W. Rose, Allen M. Katsuyama, and George E.
Wilson
VI
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MEATPACKING WASTEWATER TREATMENT BY SPRAY RUNOFF IRRIGATION 256
Jack L. Witherow, Mickey L. Rowe, and Jimmie L. Kingery
WASTEWATER MANAGEMENT AT HICKMOTT FOODS, INC. 288
George Tchobanoglous, Bill Ostertag, and Ed Fernbach
PILOT-SCALE TREATMENT OF BRINED CHERRY WASTEWATERS 323
A. F. Mauldin, B. W. Hempshill, M. R. Soderquist, D. W.
Taylor, E. Gerding, and J. Ostrin
CHARACTERIZATION AND POTENTIAL METHODS FOR REDUCING WASTE-
WATER FROM IN-PLANT SLAUGHTERING OPERATIONS 343
Donald 0. Dencker, David L. Grothman, Paul M.
Berthouex, Lawrence J. P. Scully, and James E. Kerrigan
EGG PROCESSING WASTE RECOVERY 368
N. Ross Bulley
ROTATING BIOLOGICAL SURFACE TREATMENT OF VEGETABLE CANNING
PROCESS WASTEWATER 380
Robert F. Roskopf, Francis D. Osborn, Dale A. Watson,
and G. E. Flann
A PRELIMINARY REPORT ON STUDIES TO DEVELOP ALTERNATIVE
METHODS OF REMOVING POLLUTANTS FROM TUNA (ALBACORE) PROCESS
WASTEWATERS 407
Harod J. Barnett and Richard W. Nelson
EFFLUENT VARIABILITY IN THE MEAT-PACKING AND POULTRY
PROCESSING INDUSTRIES ' 418
James F. Scaief
vii
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457
REGISTRATION LIST
viii
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INTRODUCTORY REMARKS
Lt. Governor Martin J. Schreiber
It is with a great deal of pleasure that I welcome this National
Symposium to Wisconsin. On behalf of the State, I wish you well in your
work. We are well aware that our future development here may be
significantly affected by the ideas exchanged at this symposium.
The welfare of Wisconsin, more than many other states, depends
directly on the vitality of its agricultural sector. About 30 percent
of Wisconsin's work force is in agriculture or agriculture-related jobs.
For the future, we must have a healthy and expanding agriculture and
food processing industry.
But food production and food processing is important for more than
purely economic reasons. Next to world peace, world hunger is probably
the paramount issue facing mankind.
The specter of a growing food crisis, underscored by widespread
starvation in some areas, has focused the spotlight of world attention
on America's vast food production potential. It is clear to people all
over the world that America must bear much of the burden of feeding an
increasingly hungry world.
Today, one Wisconsin farmer feeds 55 people, 13 of whom live in
foreign countries. As production grows in efficiency and volume,
hopefully we will be able to increase that number. But the efficiency
and technology of the food processing industry must keep pace.
The growth and health of agriculture and the food processing
industry will be critically important in the years ahead. But, before
that growth can take place, we must realize that important limiting
factors are at work.
First, we cannot sacrifice the quality of our water, land and air
for economic growth. The quality of life in many smaller towns can be
-------
easily affected by one food processing plant which pollutes the air, or
the water.
All of you here today are aware of this reality, and many of you
have helped contribute technical solutions to the problem. I commend
you for that work. But as the pressure to produce and process more food
increases, we will have an even greater challenge for environmental
vigilence.
Secondly, work is underway, in various areas of Wisconsin and other
states, to bring new land into production. If past patterns are
repeated, processors will follow production into these new areas. These
new plants, if and when they are built, will offer important
opportunities for many of you here today. You can meet the same
environment constraints with new ideas and new technologies, free of the
constraints of existing physical plant and machinery.
Third, here in Wisconsin particularly, we must realize that
environmental protection affects not only the quality of life for
citizens, but also the livlihood of many people. Tourism is the major
industry for the Northern part of Wisconsin. We must make certain that
future growth protects the beauty and the recreational resources which
are the foundation of that important industry.
We have been relatively successful in the past in Wisconsin because
a strong spirit of cooperation has existed between producers, processors
and all levels of government. Generally, because of this cooperation we
have not had significant problems balancing the needs of food processors
against environmental needs. I hope that similar cooperation can exist
here and throughout the Nation as the need for increased food production
grows.
It is to all of you here today that we look for answers to these
important questions. Your work, and your ideas, will determine the
degree to which Wisconsin, and other States, will successfully grow with
the demands of the future.
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INVESTIGATION OF AN ANAEROBIC-AEROBIC LAGOON SYSTEM
TREATING POTATO PROCESSING WASTES
Dr. James N. Dornbush*
Dwayne A. Rollag*
William J. Trygstad**
INTRODUCTION
Various methods of treating potato processing wastes have been
utilized during the past years, however, very limited data are available
in the literature demonstrating the effectiveness of an anaerobic-
aerobic lagoon system for treating these wastes. Midwest Foods
Corporation (formerly Fairfield Products, Incorporated) of Clark, South
Dakota, presently utilizes such a system to treat the waste water
generated from the production of frozen French-fried potatoes. The
following discussion provides a case history of the successes and
failures of the system.
When the potato processing plant was constructed prior to the 1970-
71 season, relatively little consideration was given to design and
operation of the waste handling system. The waste water treatment
facilities consisted of a screen and 25-acre stabilization pond. After
the initial operating season in 1970-71, numerous complaints regarding
offensive odors from the system were received by company and state
authorities. Data obtained in June 1971 revealed that the stabilization
pond was severely overloaded. The five-day biochemical oxygen demand
(BOD5) of the liquid contents was 1180 milligrams per liter. Acting
upon the complaints, state authorities directed the company to construct
facilities capable of satisfactorily treating the wastes prior to the
1971-72 processing season.
*Professor and Associate Professor, Civil Engineering Deparment, South
Dakota State University, Brookings, South Dakota.
**Sanitary Engineer, Zenk Engineering, Albert Lea, Minnesota.
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Waste water flows and characteristics had not been measured at the
processing plant; consequently, empirical design was a necessity. After
discussions with representatives of the state, EPA, and the Ciyii
Engineering Department at South Dakota State University, the consulting
engineers designed an anaerobic lagoon followed by a mechanicaliy
aerated basin preceding the existing stabilization pond. The anaerooic
lagoon and aerated basin were hastily constructed by the company in one
corner of the existing pond although aeration equipment was not
installed until March 1972.
During the 1971-72 potato processing season, waste water flows and
characteristics were studied1 to evaluate the treatment system.
Approximately 3500 gallons of water per ton of raw potatoes were usea
during that season and all units of the treatment system were severely
overloaded, both hydraulically and organically. Removal efficiency or
the partially completed units was low. The entire system operated
anaerobically and nuisance odors continued to generate complaints. The
high water usage in the plant coupled with unusually high rainfall
caused excessive dike erosion and ultimate disposal of the waste water
from the plant during the coming season was a serious concern.
The company instituted an intensive campaign of in-plant changes
aimed at waste reduction and water conservation after the 1971-72
operations including the installation of a dry-abrasive peeler,
elimination of the peel from the waste water, recirculation of flume
water, and cooling water reuse plus numerous minor alterations. The
anaerobic lagoon was covered with a two-inch layer of styrofoam plus a
straw mat to conserve heat and control odors. The aerators were also
operated continuously throughout the summer and the liquid contents of
the stabilization pond were recirculated through the aerated lagoon to
aid the recovery of the system and alleviate the odors.
Evidence of recovery of the system was first noticed in March 1973
and aerobic conditions prevailed in the stabilization pond at this time.
The 1973-74 waste discharge permit, issued by the South Dakota
Department of Environmental Protection, required the company to monitor
its waste discharges and loadings to the various treatment units. Data
collected through this monitoring program made it possible to determine
the value of the anaerobic pond and the flow-through aeration basins for
the treatment of potato processing wastes at little additional expense.
Consequently, a more complete investigation of the anaerobic-aerated
lagoon system was undertaken to determine both the condition of the
treatment units prior to the 1973-74 processing season, and the loading
and removal efficiency of the treatment units.
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PLANT DESCRIPTION
Figure 1 is a flow diagram of the processing plant operations. The
production line, approximately 600 feet in length, is basically a
"straight-through" process. Initially, the raw potatoes are transferred
from storage to the mudpit by fTurning. Soil and small quantities of
organic matter that settle in the mudpit are pumped, as "silt water",
periodically to a waste-receiving pit while the flume water is recycled.
The potatoes are then conveyed over a scale into the preheat tank
from which they are immersed in a hot caustic solution to loosen and
soften the skin. Peeling is accomplished by a dry abrasive peeler. The
resultant highly alkaline organic peel, which has the appearance of
peanut butter, is pumped to a pit, or a 500-gallon tank truck and
transported from the plant to be combined with corn silage and used as
cattle feed.
The peeled potatoes pass on to a trim table where culls and eyes
are removed manually. The trimmed potatoes pass to a holding tank from
which they are augered to the French-fry cutters. Slivers and other
small pieces unsuitable for packaging are removed by automatic
separators and other defective fries are removed manually. Culls, eyes,
slivers and defects are deposited in the waste flume.
The cut fries are treated by a blanching process to prevent
discoloration and preserve the product. After the fries are dewatered
using a vibrating screen, they are precooked in a deep-fat cooker.
Excess cooking oil is removed using another vibrating screen. Wastes
from blanching and cooking, including small amount of oil, reach the raw
waste stream.
Subsequently, the French-fries enter a two-stage deep freeze and
then are sized automatically. Wastes include cooling water during the
defrosting operation and the rejected fries from the sizing operation
which are used as livestock feed. After packaging, the fries are
transported to another deep freeze to await shipment.
As shown in Figure 1, the flume silt-water and raw waste water
streams evolved during sorting, cutting, blanching, cooking and freezing
were all flumed to the waste-receiving pit, pumped to a 20-mesh
vibrating screen and discharged by gravity to the lagoon treatment
system. The caustic peelings, screened solids and solids produced by
the sizing operation were removed from the plant by trucks for livestock
feed.
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Recycled Water
Water
Solid Waste
Truck
Raw
Potatoes
Mud Pit
Silt Water
Preheat Tank
Caustic Solution
Dry Abrasive Peeler
Caustic
Water
Trim Table
Water. Culls
A.
Rinse Basin
Inspection
Blanchers
Dewatering
Cooker
Degreasing
Freezing
Packaging and
Final Freezing
Water
->| Fry Cutter & Sorter [.
Water, Slivers
Defective Fries
Water
on
Cooling Water
Tank
Truck
Screened
Solids To
Truck
Sludge
Receiving
Wastewater
To Lagoons
Figure 1. Potato processing plant flow diagram at Midwest Foods
Corporation, Clark, South Dakota.
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TREATMENT FACILITIES
The waste water treatment facilities of the plant consist of an
anaerobic lagoon, aerated lagoon and stabilization pond all operated in
series as represented schematically in Figure 2.
The anaerobic lagoon is approximately rectangular in shape having a
mean width and length of 100 and 170 feet, respectively. Originally the
lagoon had a liquid depth of 20 feet but this has been reduced
substantially by the build-up of solids. The liquid volume was about
100,000 cubic feet. To preserve heat and control odors, the anaerobic
lagoon was covered with a two-inch thick layer of styrofoam topped with
a straw mat.
The aerated lagoon is triangularly shaped with a length of about
470 feet and a present volume of about 404,000 cubic feet. Originally,
the aerated lagoon had a liquid depth of 12 feet but solids deposition
has reduced the average depth to less than 10 feet. Six 25-horsepower
floating aerators are located in the basin as shown in Figure 2. Waste
water from the aerated basins flows by gravity to a 22-acre
stabilization pond. Discharge from the pond is not practiced nor
permitted.
The entire three-basin treatment system was constructed with little
attention to inlet or outlet conditions of the units. Manholes were not
constructed where pipes pass through the dikes; consequently,
operational flexibility of the system is limited to controlling the
number of aerators in operation as the waste water flows through the
system. The dikes throughout the system were reconstructed and
partially rip-rapped following serious erosion after the 1971-72
operating season.
INVESTIGATION PROCEDURES
The primary investigation reported herein was conducted during the
period of August 1 to November 14, 1973, although plant processing
operations were limited to a period of September 6 to November 14.
During this period, the plant processed an average of 4.72 tons of raw
potatoes per hour of operation or about 85 tons per day.
Samples were collected weekly from seven locations in the treatment
system as shown in Figure 2. Raw waste, anaerobic lagoon and aerated
lagoon effluent samples were composited from grab samples collected at
two-hour intervals during the day shift. Because the discharge permit
required sampling from each quadrant of the stabilization pond, four
grab samples were analyzed individually from this source. Samples were
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©
STABILIZATION POND
(22 acres)
0
ANAEROBIC LAGOON
Figure 2. Schematic flow diagram of the treatment system
showing the sampling points.
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refrigerated after collection and during transport to South Dakota State
University where the analyses were performed. The time lapse between
the end of sampling and arrival at the laboratory was less than two
hours and analyses of the samples began immediately. A total of fifteen
different determinations were performed on the waste waster samples,
with most of the analyses conducted in accordance with Standard
Methods.2 Most analyses were performed weekly although a few were made
only at monthly intervals.
Plant flows were measured using a three-inch Parshall flume
installed between the vibrating screen and the anaerobic lagoon.
Initially, a recorder was used to continuously measure flow; however,
because of excessive vibration and solids accumulation in the float
stilling well, the recorder was abandoned in favor of hourly manual flow
measurements taken during the day shift when the plant was processing.
Flume silt-water flow was estimated by recording the time of pump
operation as the solids were pumped from the mudpit.
Details concerning the sampling and compositing procedures, the
particular method employed for analyses of samples and techniques of
measuring flow have been reported.3
CONDITION OF THE TREATMENT UNITS PRIOR TO THE 1973-74 CAMPAIGN
One of the objectives of the investigation was to determine if the
anaerobic lagoon, aerated lagoon and stabilization pond had recovered
from the overloaded conditions that existed from 1970-72. The contents
of the stabilization pond were green instead of the pink that was
evident during 1970-72 when anaerobic conditions prevailed. Whereas the
pink coloration was indicative of the presence of purple sulfur bacteria
which proliferate under anaerobic conditions, the green color
demonstrated the presence of oxygen-producing algae which are normally
present in a well functioning stabilization pond. Further indication
that the stabilization pond was aerobic was the absence of any noticable
odors emanating from the pond. The aerated lagoon was also free of
odors. Slight odors were noted in the immediate vicinity of the
anaerobic lagoon. Furthermore, gas bubbles were observed at the surface
of the anaerobic lagoon which would be expected when anaerobic
decomposition was occurring.
In addition to the visual inspection of the waste water treatment
facilities, several analytical determinations were performed to evaluate
the conditions of the system. The average results obtained from these
analyses are presented in Table 1.
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Table 1. AVERAGE ANALYTICAL RESULTS PRIOR TO THE 1973-1975 CAMPAIGN
•^^^^^•^^MMMHWMBWB*~*BV-^^HI^^M^H^aWIWPI^H^BM^B^BM^
Parameter
IMIHIIIBVIIII^^^H^^^^H^^^H^MMllHa^HM^^H^^HBHHa^MM^H^M^^^^H4H
Dissolved oxygen,
mg/1
ORP, mv
N03-N, mg/1
NH3-N, mg/1
Anaerobic
lagoon
_
-358
0
133
Aerated
lagoon
4.5
+45
61
0.31
StabTTization
jinnd
8.1
+63
0.05
0.85
10
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The highly negative oxidation-reduction potential, zero nitrate-
nitrogen and high ammonia-nitrogen concentrations shown in Table 1 for
the anaerobic lagoon are results typical of anaerobic conditions. The
values presented in Table 1 for the aerated lagoon and stabilization
pond indicate that these units had returned to aerobic conditions prior
to the 1973-74 processing season. The dissolved oxygen results should
be considered approximate values because of an unexplained interference
that occurred when the samples were fixed in the field. The positive
oxidation-reduction potentials, low ammonia-nitrogen concentrations and
presence of nitrates in both units provide additional evidence in
support of the conclusion that both units were aerobic immediately prior
to the 1973-74 processing season.
QUANTITY OF RAW WASTE STREAMS
From a frequency distribution plot of flows gaged on an hourly
basis, the raw waste flow was 57 gpm or less 50 percent of the time.
Ninety percent of the time, flow was less than 125 gpm. Highest flows
occurred during plant clean-up, flushing of a plugged flume or during
defrosting operations. The average daily flow ranged from a low of
54,720 gpd to a high of 142,560 gpd. The average waste water flow
during the day shift processing period was about 64 gpm. Assuming this
average to be representative of the entire processing period, a
discharge of 92,160 gallons per day would result. Approximately 4.72
tons of raw potatoes were processed per hour of operation. Based on the
average flow of 64 gpm, approximately 813 gallons of waste water were
produced per ton of raw potatoes processed.
Silt-water was also pumped to the anaerobic lagoon on an average of
once per day. The average pumping time was 11.8 minutes at a rate of
418 gpm resulting in 4,932 gallons of silt-water produced daily. Based
on an average input of 85 tons of raw potatoes per day, approximately 58
gallons of silt-water were produced per ton of raw potatoes. It should
be noted, however, that during the 1973-74 season unusually clean
potatoes were received at the plant.
RAW WASTE CHARACTERISTICS
The quantity of raw potatoes processed per day varied considerably,
ranging from 41 to 122 tons with an average of 85 tons. The
characteristics of the raw waste were also highly variable. On at least
one occasion, cautic peel was discharged to the waste stream causing
maximum concentrations of suspended solids (SS), and chemical oxygen
demand (COD) and a very high pH.
11
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The average characteristics (except pH) of the raw waste are
included in Table 2. The pH of the raw waste ranged from 9.2 to 11<6'
The median pH value was 10.6 which was lower than the median pH of 11.4
obtained in the 1971-72 study,1 undoubtedly the result of the reduction
in caustic peel allowed to enter the waste stream. Temperature of the
raw waste varied from 23 degrees to 27 degrees C with the average being
about 25 degrees C.
The impact of the new peeling process and the implementation of
extensive water conservation measures were clearly evident when the
BOD 5, SS and COD concentrations shown in Table 2 were compared with the
1971-72 study. The BOD5 and COD concentrations shown in Table 2 were
about 70 percent higher than determined two years earlier while SS
concentrations were about 225 percent higher. However, waste water
flows during this period had been reduced from 3500 to 813 gallons per
ton of potatoes processed. These concentrations would be considered
excessive for the potato processing plant had it not been for the
reduced flows. The BOD5, COD and SS loadings were 40.5, 84.6, and 67.7
pounds per ton of raw materials processed, which are quite
representative of the industry.
Total Kjeldahl nitrogen (TKN) and inorganic phosphorus tests were
performed to determine if sufficient nutrients were present in the raw
waste to support biological growth. The most commonly quoted
requirement of the BOD:N:P ratio for aerobic biological treatment is
100:5:1 while the raw waste water from the plant had a ratio of
100:7.1:26.7. It would appear that adequate nutrients to support
aerobic biological growth were present although nitrogen deficiencies
might occur during periods of extreme quality variation.
Analyses of the flume silt waste pumped daily to the waste stream
were limited to solids determinations. For five samples of the silt
water, mean concentrations were 14,044 milligrams per liter of SS and
61.1 milliliter per liter of settleable suspended solids after a 23-hour
settling time.
Using average SS concentration of 14,044 milligrams per liter and
the average daily volume of 4,932 gallons, it was calculated that 578
pounds of silt (6.8 pounds per ton of potatoes) were pumped to the
anaerobic lagoon per operating day. Assuming this silt would occupy an
average volume of 61.6 milliliters per liter in the anaerobic lagoon
after settling, an average of 40.5 cubic feet of compacted silt was
produced per operating day during the 1973-74 season. At this rate, a
normal production year of about 245 days would produce approximately
9,925 cubic feed of compacted silt resulting in a 9.8 percent reduction
in anaerobic lagoon.
12
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Table 2. MEAN CONCENTRATIONS AT TREATMENT UNITS
Determination3
Temperature, °C
pH - units
(median)
BOD 5
COD
SS
Total residue
Conductivity,
ymho/cm
ORP, mv
Volatile acids
Total alkalinity
DO
Phosphorus
TKN
N03-N
NH3-N
Raw waste
(screened)
25.1
10.6
5,978
12,489
9,993
17,127
6,801
-
-
2,590
-
1,277
308
0.22
29.3
Anaerobic
lagoon
22.7
7.1
1,573
4,692
2,200
7,554
6,480
-396
956
3,853
-
706
180
0
50.2
Aerated
lagoon
12.9
8.85
251
815
712
6,017
6,740
-52
-
3,527
1.2
450
44.4
56
5.1
Stabilization
pond
11.7
9.5
59
471
149
6,678
8,567
-11.6
-
5,038
14.2
260
22.1
0.16
0
All units in mg/1 unless otherwise noted.
13
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TREATMENT ACCOMPLISHMENTS
Table 2 also Includes the mean concentrations of samples
representing the effluent of the anaerobic lagoon and the aerated basin
as well as the contents of the stabilization pond. Becuase flow is
straight through the units, comparison of the concentrations WIN
demonstrate the removals accomplished by the individual treatment units.
Anaerobic Lagoon
During the period of the investigation, the average retention time
provided by the anaerobic lagoon was 8.2 days. Conditions for anaerobic
treatment of the wastes were certainly satisfactory in that the median
pH was 7.1 with a range of 6.8 to 7.4 and the temperature averaged 22.7
degrees C. Volatile acids ranged from a maximum of 1,380 milligrams per
liter early in the investigation to 570 milligrams per liter on the last
sample collected, with a mean concentration of 976 milligrams per liter.
The mean volatile acids to alkalinity ratio was 0.25 and the oxidation-
reduction potential (ORP) was -396 mv. These conditions have been
described" as satisfactory for the continued conversion of the organic
material in the lagoon to carbon dioxide and methane.
It is important to note that the raw waste pH was reduced from 10.6
to about neutrality (pH of 7.1) in the anaerobic lagoon. The buffering
capacity of the system seemed to be highly effective even when the pH of
the raw waste was 11.4 to 11.6.
Temperature of the anaerobic lagoon was above 21 degrees C
throughout the investigation, only a few degrees lower than that of the
raw waste. This temperature is well above a recommended minimum value
of about 15 degrees C at which anaerobic biological activity is sharply
curtailed. During the 1971-72 investigation of the system when the
anaerobic lagoon was uncovered, the average temperature was about 12
degrees C. Thus, the styrofoam-straw cover presently employed appears
to have contributed substantially to maintaining a more suitable
temperatue in the anaerobic lagoon.
The loading rates and removal efficiencies for the anaerobic lagoon
are included in Table 3.
These loading rates are substantially higher than those generally
recommended for design of anaerobic lagoons. For example, the BODS
loading of 45.5 pounds per 1,000 cubic feet per day was three times
higher than that recommended for anaerobic lagoons in South Dakota.
However, the unit obtained a 73.7 percent removal of BOD5 with nearly
comparable removals of COD and SS.
14
-------
Table 3. LOADING RATE AND REMOVAL EFFICIENCY TREATMENT UNITS
Location
Anaerobic lagoon,
Ibs/l,000ft3/day
BOD5
COD
SS
Aerated lagoon,
lbs/1,000 ftVday
BOD 5
COD
SS
Stabilization pond,
1 bs/acre/day
BOD 5
COD
SS
Lagoon system,
1 bs/acre/day
BOD 5
COD
SS
Loading rate
45.5
90.0
76.0
3.0
8.9
4.2
8.8
28.5
24.9
«
Removals, %
73.7
62.4
77.9
81.8
82.6
67.6
76.5
42.2
79.1
99.0
96.2
98.5
aBased on the average daily flow of 92,160 gallons.
15
-------
Although the removals for the anaerobic lagoon were based on
samples collected over a comparatively short period and did not include
data during a severe winter period, the removals appear representative
of the unit during winter conditions. For example, thirteen samples
collected during the current season from October 1974 through March 1975
had mean removals of 77.5 and 7.1. percent, respectively, for BODs and
SS.
Sufficient inorganic nutrients were present in the anaerobic lagoon
effluent to support aerobic biological activity as indicated by an
average BODs:N:P ratio of 100:25:90. Whereas the raw waste BODs:N:P
ratio was 100:7.1:26.7, indicating a possible nitrogen deficiency at
certain times, the BODs:N:P ratio present in the anaerobic lagoon
effluent reveals that the anaerobic lagoon conserved the inorganic
nutrients discharged to it. The increased nitrogen fraction was
probably due to the reduction in carbon (BOD) brought about through the
escape of carbon dioxide and methane from the degradation of nitrogen-
containing compounds. Because of the higher cellular growth rates and
commensurate requirement for nitrogen, an aerobic treatment unit would
probably not bring about a similar conservation of nitrogen. Therefore
the use of an anerobic lagoon appears to be of considerable value in
providing a BOD5:N:P ratio suitable for biological treatment of potato
wastes which might otherwise have been nitrogen deficient.
Aerated Lagoon
During the investigation, the aerated lagoon provided an average
retention time of near 33 days, substantially longer than would normally
be considered in design of a similar unit. Undoubtedly, this long
retention time was the result of the reduction of waste flows through
water conservation measures within the plant prior to the investigation.
Maintaining adequate dissolved oxygen in the aerated lagoon was a
problem throughout the investigation. Although the mean concentration
of dissolved oxygen was 1.2 milligrams per liter, on two occasions
dissolved oxygen was zero when at least one of the six 25-horsepower
aerators was not operating. Consequently, it is likely that an oxygen
deficiency existed periodically in the aerated lagoon although odors
from this unit were not a problem.
Low temperatures in the aerated lagoon were not a problem during
the investigation with an average of 12.9 degrees C; however, with
extremely cold weather, icing difficulties have occurred. In mid-
January 1975, a severe blizzard occurred and the floating aerators iced
to the extent that several completely overturned. During the one and
one-half months that the aerators were inoperative, the aerated basin
became completely covered with ice, turned anaerobic and effluent'
16
-------
quality from the basin approached that of the anaerobic lagoon. When
the aerators were placed in operation, extremely noisome odors persisted
for a few days; however, about ten days later the BOD5 of the effluent
was reduced to 450 milligrams per liter and the odor problem was
eliminated.
The loading rates and removal efficiencies of the aerated lagoon
are included in Table 3. These loading rates were low and,
consequently, average removal of BODs, COD and SS were high, 81.8, 82.6
and 67.6 percent, respectively. From the SS reduction, it is obvious
that the aerators do not provide adequate mixing of the basin contents
and that sedimentation plays an important part of the overall removals
of the unit.
Stabilization Pond
The mean concentrations of the contents of the stabilization pond
are included in Table 2. The BOD5 and SS concentrations of the pond
exceeded the limits extablished for discharge to surface waters in South
Dakota and, without additional treatment, could not have been
discharged. However, because of the low hydraulic loading to the pond,
no direct discharge from the pond existed. The unit has served
effectively as an evaporation pond for ultimate disposal of the waste
water throughout the five years of service and only during the summer of
1972 was it necessary to employ some spray irrigation for the purpose of
reducing the lagoon volume.
Prolific algal concentrations were the cause of the high SS
concentrations in the pond and dissolved oxygen was always present in
the pond with a mean concentration of 14.2 milligrams per liter. It
appears from the total Kjeldahl and ammonia nitrogen results that the
algae have utilized nearly all the available nitrogen in the pond.
During the 1973-74 processing season, the BOD5 loading to the
stabilization pond was low, averaging only 8*8 pounds of BODs per day.
Consequently, overall reductions of BODs in the pond were 76.5 percent
(Table 3). By contrast, COD removals were only 42.2 percent, probably
because of the high algae concentrations.
Lagoon System
The removals of the individual units and the lagoon system as a
whole are presented in Table 3 comparing the influent and effluent
concentrations. It will be observed by BODs, COD and SS removals for
the entire system were all in excess of 96 percent.
17
-------
To emphasize the relative importance of the individual units,
however, the removals based upon the raw waste load are shown in Figure
3. From these pie graphs it is obvious that the anaerobic lagoon is the
principal unit of the system accomplishing nearly 75 percent of the
overall removal. Furthermore, the anaerobic lagoon during the period of
this investigation operated essentially free of objectionable odors.
Odors from the stabilization pond have been the primary problem for
the waste system and these were severe for the first two years when
little attention had been given to water conservation and waste
recovery. The water used at the plant contains a concentration of
sulfates in excess of 400 milligrams per liter, and the production of
hydrogen sulfide no doubt intensifies the nuisance odors. When the
stabilization pond turned pink in 1971, probably as a result of
photosynthetic sulfur bacteria as described by Sletten,5 a marked
reduction in nuisance odors occurred. This pink color persisted until
aerobic conditions were established in the stabilization pond the
following summer.
It is not suggested that a treatment system of the nature described
would be equally successful for all similar potato processing plants.
The success of the overall system can, however, be attributed primarily
to the anaerobic lagoon. Even after the anaerobic-aerated lagoon
components were added to the existing stabilization pond, at least a
year was required before the anaerobic lagoon was functioning properly.
Because of time limitations, little consideration had been given to
providing the seed organisms required to rapidly establish an active
population of methane-forming organisms necessary to break down the
wastes without producing odors. During the time period between
processing campaigns, active anaerobic digestion was established
naturally, and this time period when processing wastes do not enter the
system appears highly beneficial toward recovery of the entire system.
SUMMARY AND CONCLUSIONS
This investigation of the treatment system for the potato
processing wastes at Midwest Foods Corporation, Clark, South Dakota,
covered a three and one-half month period. During this time, analytical
determinations and flow measurements were utilized to calculate loadings
and removal efficiencies for the various treatment units. The following
conclusions were drawn:
1. Immediately prior to the 1973-74 processing season, aerobic
conditions prevailed in the aerated lagoon and stabilization
pond indicating that these units had recovered from the
overloaded conditions that existed prior to that time.
18
-------
Anaerobic
Lagoon
73.72
Remaining 1.0%
Stabilization Pond 3.2%
Anaerobic
Lagoon
77.9%
Anaerobic
Lagoon
62.4%
Remaining
3.8%
Stabilization
Pond 2.8%
Stabilization
Pond 5.7%
Remaining 1.5%
Figure 3. Average removals obtained by the various treatment units
based on raw waste characteristics.
19
-------
2. Utilization of a new dry-caustic peeling process and extensive
in-plant water conservation had reduced the water usage from
3,500 gallons per ton of raw potatoes to approximately 813
gallons per ton.
3. The anaerobic lagoon was an effective treatment unit in which
average BOD5 and SS removals of 74 and 78 percent,
respectively, were obtained despite an average BOD5 loading
rate of 45.5 pounds per 1,000 cubic feet per day, over three
times higher than the recommended design value.
4. The styrofoam-straw cover on the anaerobic lagoon was effective
in maintaining an adequate temperature in the lagoon and
helpful in controlling odors. Although slight odors were
detected in the vicinity of the anaerobic lagoon, they were not
considered a nuisance during the period of investigation.
5. It is evident from the BODs:N:P ratios obtained that it is
advantageous to use an anaerobic lagoon prior to aerobic
treatment if conservation of inorganic nutrients is desired.
6. The aerated lagoon, operating well within the BODS loading
range, performed within anticipated efficiencies removing 82
percent of the BOD5 and 68 percent of the SS.
7. The stabilization pond was operating at about 50 percent of its
design BOD6 loading. The BOD5 and SS removal efficiencies in
this unit were 77 and 79 percent, respectively.
8. During this investigation, overall average removal efficiencies
of the treatment system of 99, 98.5 and 96.2 percent were
obtained for BOD5, SS and COD respectively.
9. Silt build-up at the present rate of 40.5 cubic feet per
operating day, could eventually decrease the volume of the
anaerobic lagoon, thus reducing the retention time in the
lagoon and possibly the efficiencies obtained by the anaerobic
lagoon.
20
-------
REFERENCES
1. Hagin, T. L. A Study of the System Treating Potato Processing
Wastes at Fairfield Products, Inc., Clark, South Dakota. Master of
Science Thesis, South Dakota State University, Brookings. 1972.
2. American Public Health Association, Inc. Standard Methods for the
Examination of Water and Wastewater, 13th edition. New York.
1971.
3. Trygstad, W. J. Investigation of the Anaerobic-Aerobic Treatment
System Treating Potato Processing Wastes, Midwest Foods
Corporation, Clark, South Dakota. Master of Science Thesis, South
Dakota State University, Brookings. 1974.
4. Dornbush, J. N. State-of-the-art: Anaerobic Lagoons. Second
International Symposium for Waste Treatment Lagoons, distributed by
Ross E. McKinney, University of Kansas, Lawrence. 1970. p. 382-
387.
5. Sletten, 0. and R. H. Singer. Sulfur Bacteria in Red Lagoons.
Journal of Water Pollution Control Federation. (43):2118. 1971.
21
-------
UTILIZATION OF CHITOSAN FOR RECOVERY OF COAGULATED
BY-PRODUCTS FROM FOOD PROCESSING WASTES AND TREATMENT SYSTEMS
Wayne A. Bough*
D. R. Landes*
Josephine Miller*
C. T. Young*
T. R. McWhorter**
INTRODUCTION
Chitosan Is a polymer composed of glucosamine residues which are
linked by 3,1-4 glycosidic bonds as shown in Figure 1. It is
manufactured from shrimp and crab wastes by the following sequence of
steps: (1) extraction of mineral components in dilute hydrochloric acid,
(2) extraction of protein components with dilute alkali * (3)
deacetylation of the chitin exoskeleton (poly N-acetylgucosamine) with
hot concentrated alkali, and (4) recovery and drying. The time and
temperature conditions for hydrolyzing the acetyl group especially
influence the characteristics of the chitosan product. Shorter times,
higher temperatures, and exclusion of air generally produce chitosan
products with less degradation of the polymer structure and higher
viscosities.1'2 The various factors affecting the properties of the
chitosan product including different manufacturing conditions and
molecular weight distribution need considerable study.
This laboratory has been investigating for the past two years the
effectiveness of chitosan for treatment of various food processing
wastes. Results have shown chitosan to be an effective coagulating
*Department of Food Science, University of Georgia College of Agri-
culture Experiment Stations, Georgia Station, Experiment, Georgia
30212.
**Hussey, Gay and Bell, Inc., Savannah, Georgia 31405.
22
-------
CH2OH
n
Figure 1. Structure of chitosan.
23
-------
agent for reduction of suspended solids in processing wastes from
vegetable, poultry, and egg breaking plants.3"**5 It has been tested
also on cheese whey, seafood wastes, meat wastes, and activated sludge.
Chitosan has been particularly effective with protein-containing wastes.
Recovery of the coagulated by-products obtained by treatment with
chitosan and utilization of these by-products in animal feeds is a
potential option for treatment of concentrated wastes from ^ food
processing plants. This paper reports results of pilot scale testing of
chitosan for coagulation and centrifugal recovery of activated sludge at
a brewery and at a vegetable cannery. The major vegetables canned at
the latter plant are pimentos, leafy greens, and green beans. Proximate
and amino acid analyses of coagulated by-products from brewery sludge,
vegetable cannery sludge, and egg breaking wastes are reported. The
results of a preliminary study on the physiological effects of chitosan
in rat diets are presented.
METHODS
Chitosan was obtained from Food, Chemical, and Research
Laboratories, Inc., Seattle, Washington, under a program funded by the
National Sea Grant Program to supply research quantities of material.
The crude chitosan product typically contained 91 percent chitosan, 5 to
8 percent water, and 0.5 to 0.8 percent ash. Solutions of 20 grams per
liter crude chitosan in 1 percent acetic acid has viscosities of 140 to
180 cps at 20 degrees C as measured with a Brookfield Viscometer.
Effects of chitosan on conditioning of brewery sludge were
evaluated with Buchner funnel filterability test.6 Laboratory studies
on conditioning were conducted over a six-week period on a total of 13
samples received from the brewery.
The centrifuge used in conjuntion with the brewery sludge
experiments was a Sharpies BD-1 unit from Pennwalt Sharpies, Warminster,
Pennsylvania. During polymer tests, activated sludge from the main
plant clarifier underflow was fed into the continuous centrifuge at a
rate of 26 to 32 gallons per minute. The characteristics of the sludge
remained constant throughout these experiments. fThe feed rate and
settings were optimized for the centrifuge to operate with the aid of a
polymer for conditioning the sludge. Control tests without polymer were
also made at these settings. The bowl speed of the centrifuge was 3,250
to 3,300 rpm and the pond depth was held constant. The speed of the
conveyor which removed the sludge cake was varied to give a speed
differential of from 3 to 17 rpm. Chitosan was injected into the
centrifuge as a solution of 2 grams per liter crude chitosan in 0.7
percent acetic acid.
24
-------
Tests on activated sludge from vegetable canning wastes were
conducted with a pilot-scale centrifuge, Model STM-1000, from Western
States Machine Company, Hamilton, Ohio. Thickened sludge from the main
plant clarifier underflow was pumped into the batch centrifuge at a
desired feed rate until the breakpoint where the capacity of the basket
was exceeded. The centrifuge speed was 3,200 rpm which corresponded to
1,740 times gravity. Chitosan as a solution of 5 grams per liter in 1
percent acetic acid or 1 gram per liter in 0.2 percent acetic acid was
injected into the basket through a spray nozzle by the action of a
tubing pump. Synthetic polymers WT-2680, WT-2660, WT-2640, WT-3000,
Natron 86, Floe 534, Floe 535, Betz 1190, Betz 1160, and Atlasep 105c
were applied as solutions of 1 gram per liter in water.
Centrifugal studies at a brewery and a vegetable canning operation
were evaluated by assaying suspended solids in the sludge feed and
centrate and by determining total solids in the sludge cake.7 The flow
rates of the centrate in the brewery study, or the sludge feed at the
vegetable canning plant, were determined as well as the polymer feed
rates for each experiment and set of samples. This data was necessary
to calculate the concentration of chitosan in the sludge feed.
Coagulated sludge samples for analysis were freeze-dried to avoid
heat damage to protein components. These were analyzed for crude
protein,8 fat, ash, and in some cases fiber.9 Protein components
extractable with alkali were determined by a biuret method developed by
Herbert et al. for microbial protein.10 Amino acid composition of acid
hydrolysates was determined with a Durrum Amino Acid Analyzer System.11
Tryptophan in brewery sludge was determined by the microbiological
method of Henderson and Snell.12 Tryptophan analyses were performed by
WARF Institute, Inc., Madison, Wisconsin.
Physiological effects of chitosan in rat diets were explored in a
preliminary experiment. Weanling Sprague-Dawley male rats (five per
treatment) were fed ad libitum for five weeks on a standard casein
diet13 in which chTtosan at levels of 0, 0.5, 1.0, 2.0 and 5.0 percent
replaced a corresponding amount of sucrose. The animals were sacrificed
at the end of the experimental period; and total hemoglobin1" and
hematocrit, using micro-hematocrit tubes, were determined. The livers
were removed and liver weights determined.
25
-------
DISCUSSION
Brewery Sludge
Suspended solids in the thickened brewery sludge ranged from 8,000
milligrams per liter to 15,000 milligrams per liter. Figure 2 shows the
results of a typical Buchner funnel filterability test. The optimum
ratio of chitosan to suspended solids appeared to be between 0.6 and 0.8
percent.
First tests with the full-scale continuous Sharpies centrifuge at
the brewery were conducted to determine the optimum differential speed
between the bowl and the sludge conveyor. Figure 3 shows that a
differential setting of 3 rpm resulted in a dry cake containing nearly
10 percent solids, but the centrate contained over 9,300 milligrams per
liter suspended solids compared to 11,000 to 12,000 milligrams per liter
in the sludge feed. Treatment with chitosan at a differential setting
of 3 rpm resulted in the capture of 30.7 percent of the suspended solids
compared to 22.4 percent capture in the control trial with no polymer.
Increasing the differential speed to 12 rpm increased the capture of
suspended solids to approximately 70 percent. A differential of 17 rpm
and treatment with 76 milligrams per liter chitosan (0.64 percent)
resulted in a sludge cake containing 7.3 percent total solids. The
centrate contained 602 milligrams per liter suspended solids which
corresponded to 94.9 percent capture.
The effects of varying the chitosan concentration while maintaining
a differential speed setting of 17 rpm are shown in Figure 4. Using a
ratio of 0.6 to 0.8 percent chitosan to suspended solids resulted in a
sludge cake containing approximately 7.5 percent solids and a centrate
containing less than 600 milligrams per liter suspended solids. This
corresponds to 95 percent capture of suspended solids from the sludge
feed which contained approximately 12,000 milligrams per liter suspended
solids.
Vegetable Canning Sludge
Initial tests to determine the optimum amount of chitosan showed
(Figure 5) that a ratio of chitosan to suspended solids in the sludge
feed of 0.2 to 0.3 percent resulted in the centrate containing less than
200 milligrams per liter suspended solids compared to approximately
16,000 milligrams per liter in the sludge feed. This amounted to
approximately 99 percent capture of suspended solids from the sludge
which was fed into the centrifuge at a rate of 8 to 9 liters per minute.
The total solids content of the sludge cake was 9.7 percent
26
-------
0.1 0.2 0.3 0.4 O.S 0.6 0.7 0.8 0.9 1.0 1.1 1.2
RATIO OF CHITOSAN/SUSPENDED SOLIDS (%)
Figure 2. Buchner funnel filterability test to evaluate
conditioning of activated sludge from brewery with chitosan.
27
-------
10000
8000
6000
4000
oo
2000
co 0
Chitosan, mg/l G
Differential, rpm
10
8
2 o
Figure 3. Effects of speed differential between bowl and conveyor
of continuous centrifuge and of chitosan concentration on
suspended solids in centrate and total solids in
sludge cake from brewery activated sludge.
28
-------
CO
CO
oi
CO
CO
2400
2000
1600
1200
800
400
0
T. S.
10
8
6
2
0
0.0 0.2 0.4 0.6 0.8 1.0 1.2
RATIO OF CHITOSAN TO SUSP. SOLIDS
IN SLUDGE FEED, %
CO
4 =
CO
Figure 4. Effects of chitosan concentration on suspended solids in
centrate and total solids in sludge cake obtained by continuous
centrifugation of brewery activated sludge.
(Centrifuge bowl speed was 3,300 rpm and differential was 17 rpm.)
29
-------
f 120°
*
£ 1000
PC
z 800
CO
o
CO
CO
CO
600
400
200
12
10
8
4
2
0.0 0.1 0.2 0.3 0.4 0.5 0.6
RATIO OF CHITOSAN TO SUSP. SOLIDS
IN SLUDGE FEED. %
CO
CO
Figure 5. Effects of chitosan concentration and suspended solids in
centrate and total solids in sludge cake obtained by batch
centrifugation of vegetable cannery activated sludge.
(Sludge feed rate was 8 to 9 1/min; centrifuge speed was 3,200 rpm.)
30
-------
corresponding to a chltosan concentration of 40 mi Hi grains per liter or
a ratio of 0.27 percent chitosan to suspended solids.
The effects of varying the sludge feed rates and the presence or
absence of 40 milligrams per liter chitosan on suspended solids in the
centrate and total solids in the cake are shown in Figure 6. At sludge
feed rates below 10 liters per minute, the capture of suspended solids
(92 to 99) was greater than the capture at higher feed rates. Total
solids in the sludge cake was approximately one percentage point higher
when chitosan was added regardless of the feed rate. At a feed rate of
12.75 liters per minute, the control trial without polymer resulted in
4,500 milligrams per liter suspended solids in the contrate (72.2
percent capture) and 8.4 percent total solids in the sludge cake.
Treatment with 40 milligrams per liter chitosan reduced suspended solids
to 280 milligrams per liter (98.3 percent capture) and increased total
solids in the cake to 9.2 percent. Thus, chitosan effectively increased
solids capture while permitting the sludge to be fed into the centrifuge
at a higher flow rate.
Table 1 shows a comparison of chitosan and ten commercially
available polymers. All were cationic polymers except WT-3000 which is
an anionic polyelectrolyte. All of the polymers, when applied to the
sludge feed at 40 milligrams per liter, resulted in a capture of 93
percent or more of the suspended solids compared to 87.5 percent in the
control. The lowest suspended solids and turbidity levels in the
centrate were effected by chitosan, WT-2660, Natron 86, and Atlasep
105c. The first three of these were chosen for further evaluation.
Table 2 shows a comparison of chitosan, WT-2660, and Natron 86 applied
at 10, 20, and 40 milligrams per liter to the vegetable sludge.
Experiment No. I was conducted using a sludge feed rate of 8.6 liters
per minute while suspended solids in the feed ranged from 10,000 to
18,000 milligrams per liter. Increasing the concentration of each
polymer reduced the suspended solids in the centrate and increased
capture of suspended sludge solids accordingly. Experiment No. II was
done at a higher sludge feed rate (13.3 to 14 liters per minute), but
the concentration of suspended solids in the feed were lower (1,500 to
9,200 milligrams per liter) because sludge has been removed from the
clarifier for disposal prior to this set of experiments. However, the
same trend was apparent as in Experiment No. I. The results of both
experiments showed that chitosan was competitive with, if not superior
to, the synthetic polymers tested for conditioning of activated sludge
to aid in centrifugal recovery of the sludge solids.
It remains to be seen if the price of chitosan will also be
competitive. It is estimated from our experience that chitosan would
have to sell for $1 to $2 per dry pound to be competitive with the price
of other commercially available polymers. Food, Chemical, and Research
Laboratories, Inc., continue to produce chitosan in their pilot plant in
31
-------
- 8000
^> 6000
* 4000
i-
K 2000
m 11
o '!
5 600
g 400
g 200
Q
£ 100
z 8C
£ 60
to 40
CO
20
S.S. (Control),
2 4 6 8 10 12 14
SLUDGE FEED RATE, l/min.
20 m-
d£
10 o
6 ~
4 i
2 S
Figure 6. Effects of sludge feed rate with and without 40 mg/1
chitosan on suspended solids in centrate and total solids
in sludge cake from batch centrifugation of
vegetable cannery activated sludge.
32
-------
Table 1. COMPARISON OF POLYMERS AT 40 mg/1 TO AID
IN CLARIFICATION OF VEGETABLE ACTIVATED SLUDGE
SUSPENSIONS3 BY CENTRIFUGATIONb
Polymer,
40 mg/1
None
Chitosan
WT-2680
WT-2660
WT-2640
Natron 86
Floe 534
Betz 1190
Betz 1160
Atlasep 105c
Floe 535
WT-3000
Turbidity
FTU
600
45
210
45
290
25
125
69
67
48
66
720
Suspended solids
in centra te
mg/1
1,804
171
857
217
1,256
128
791
396
411
233
346
2,743
% capture
87.5
98.8
94.4
98.7
93.0
99.0
94.0
97.1
97.1
98.8
97.8
83.1
iSludge feed: 8.1 to 8.7 1/min, suspended solids,
12,500 to 19,600 mg/1.
^Centrifuge speed: 3,200 rpm (1,740 G's).
33
-------
Table 2. COMPARISON OF CHITOSAN, WT-2660, AND NATRON 86 AT DIFFERENT
CONCENTRATIONS TO AID IN CLARIFICATION OF VEGETABLE ACTIVATED
SLUDGE SUSPENSIONS BY CENTRIFUGATION
co
Experiment
Number
I
II
Polymer
Sludge feed rate, 8.6 l/mina
Chitosan
WT-2660
Natron 86
Sludge feed rate, 13.3 to
14 l/minb
Chitosan
WT-2660
Natron 86
Concentration of polymer, mg/1
10
20
40
Suspended solids in centra te
mg/1
321
1,255
1,047
204
260
267
% cap.
97.9
92.5
93.7
97.8
90.0
93.9
mg/1
248
697
565
150
219
182
% cap.
98.4
96.1
96.5
97.1
92.3
97.4
mg/1
177
285
177
92
63
72
% cap.
98.5
97.4
98.2
98.8
95.6
97.5
Suspended solids in sludge feed ranged from 10,000 to 18,000 mg/1.
Suspended solids in sludge feed ranged from 1,500 to 9,200 mg/1.
-------
Seattle, Washington.15 Marine Commodities International, Inc., is
constructing a plant in Brownesville, Texas for production of chitin,
chitosan, and protein by-products.16
Composition of Coagulated By-Products
The coagulated by-products derived from treatment of food
processing wastes generally contain significant amounts of protein, and
in some cases, fat. Table 3 shows the proximate analysis (dry weight
basis) of three samples of coagulated brewery sludge. The content of
fat, fiber, and ash averaged 2.0, 6.6, and 16.1 percent, respectively.
Crude protein content, determined by Kjeldahl analysis (N x 6.25) was
50.8 percent. However, the Kjeldahl values include nitrogen in cell
wall structures, such as amino sugars and D-amino acids, nitrogen in
nucleic acids, as well as nitrogen in intracellular proteins. Based on
the total amino acids found in acid hydrolysates of the coagulated
brewery sludge, the true protein content was 36.9 percent rather than
50.8 percent obtained by Kjeldahl analysis. The biuret method developed
for microbial protein10 such as found in activated sludge involves
treating the biomass with boiling 3 N^alkali for five minutes to extract
most intracellular proteins. The protein content estimated by this
biuret method was 40.7 percent compared to 36.9 percent by amino acid
analysis and 50.8 percent by Kjeldahl analysis. This biuret method for
protein is much simpler and less expensive for routine analysis than
obtaining a complete amino acid analysis. We have used this method
effectively for "single cell protein" produced from meat packing
wastes17 and are currently using it to estimate protein on a wide range
of waste products. In activated sludge, which is a mixture of
microorganisms, analysis of intracellular protein is the best indicator
of the protein nutritionally available for animals. Work with pure
cultures of microorganisms for production of "single cell protein" has
shown that the nutritionally valuable proteins are those contained
inside the cell walls of the microorganisms. Nitrogen in cell walls and
nucleic acids is of little or no nutritional value to non-ruminant
animals.18'19
The analysis of coagulated activated sludge from treatment of
vegetable canning wastes is shown in Table 4. Fat and ash were 0.7
percent and 20.2 percent, respectively. The high ash content of the
sludge is believed to be due in part to adsorption of clay and minerals
from wastewaters produced by washing of leafy greens and root crops in
the plant. The crude protein content was 33.6 percent by Kjeldahl
analysis. Based upon the amino acid content, the protein content was
28.5 percent while the biuret method estimated intracellular protein to
be 31.4 percent of the dry weight.
35
-------
Table 3. PROXIMATE ANALYSIS OF COAGULATED BREWERY SLUDGE3
Component
Fat
Fiber
Ash
Crude protein (N x 6.25
Protein by ami no acid
analysis
Protein by biuret method
Content. %
Average
2.0
6.6
16.1
50. 8C
36.9
40.7
Range
1.4-2.6
6.2-7.1
14.0-20.1
49.7-52.0
36.5-37.2
38.1-42.0
aRatio of chitosan to suspended solids in sludge was 0.72
to 0.82%.
Average of three samples.
clncludes approximately 0.06 g N in chitosan/100 g sludge
which accounts of 0.7% of total N.
36
-------
Table 4. PROXIMATE ANALYSIS OF COAGULATED VEGETABLE SLUDGEC
Component
Fat
Ash
Crude protein (N x 6.25)
Protein by ami no acid
analysis
Protein by biuret method
Content, %
Average
0.7
20.2
33. 6C
28. 5d
31.4
Range
0.2-1.2
15.9-24.5
31.9-36.2
27.4-30.3
27.5-33.0
Ratio of chitosan to suspended solids in sludge was 0.3
to 0.4%.
Average of four samples.
clncludes approximately 0.027 g N in chitosan/100 g sludge
which accounts of 0.5% of total N.
Average of two samples.
37
-------
Table 5 shows the proximate analysis of coagulated solids from egg
breaking wastes. This material contained 4.9 percent ash and 39.4
percent fat. The crude protein content was 45.6 percent compared to
41.8 percent protein by amino acid analysis.5
The essential amino acids in the coagulated by-products from egg
breaking wastes, vegetable cannery sludge, and brewery sludge are
compared in Table 6 to the FAO pattern of essential amino acids and to
meat and milk. The composition of Brewer's Single Cell Protein (BSCP)
produced by drying of activated sludge at the Adolph Coors Co., Golden,
Colorado, is also shown.21 The coagulated by-products contained
adequate amounts of all of the essential amino acids with the exception
of the sulfur-containing amino acids cystine and methionine. The acid
hydrolysis method used in this study destroyed cystine, tryptophan, and
a portion of the methionine. Hence, values for two of these amino acids
were, with the exception of tryptophan in brewery sludge, unavailable.
The amino acid content of Coor's sludge21 and the brewery sludge
analyzed in this study are similar. The Coor's sludge product contained
8.0 percent fat, compared to 0.7 percent in this study, because it was
dried with the Carver-Greenfield process which uses a fluidized bed of
oil to suspend the product.22 Dry solids are separated from the oil- by
centrifugation, but some of the oil remains in the product.
Activated sludge produced from citrus wastes has been evaluated by
Damron et al. as a poultry feed ingredient.23 This citrus sludge
contained^ 3O percent protein which compares closely with an average of
36.9 percent based on amino acid analyses of brewery sludge samples in
this study. Feeding citrus sludge to hens improved yolk color in eggs.
This enhancement may be due to citrus pulp solids which were possibly
recovered and dried along with the activated sludge solids.
Physiological Effects of Chitosan on Rats
In order for coagulated by-products to be recycled into animal
feeds, it will be necessary to obtain approval from the Food and Drug
Administration for incorporation of small amounts of the coagulating
agent into feeds.2I* In our preliminary feeding trial with rats, the
animals fed all but the highest level (5 percent) of chitosan grew as
well as those fed the control diet without added chitosan as indicated
by final weight of animals and feed efficiency (Table 7). The animals
were healthy and vigorous and displayed no overt symptons of physio-
logical distress due to consumption of the chitosan. The normal values
obtained for hemoglobin and hematocrit levels in the blood (Table 8) are
further evidence of the general well-being of the animals. The most
noticeable effect of additions of the polymer to the the diets was a
reduction in the final weight of the animals with the highest level of
chitosan. This might be due to palatability factors such as the size
38
-------
Table 5. PROXIMATE ANALYSIS OF COAGULATED SOLIDS FROM
EGG BREAKING WASTES3
Component
Fat
Ash
Crude protein (N x 6.25
Protein by ami no acid
analysis
Content, %
Average
39.4
4.9
45.6
41.8
Range
35.1-45.3
2.9-8.8
42.2-49.4
37.1-47.3
Table 7 from Bough.5
Average of five samples.
39
-------
Table 6. A COMPARISON OF ESSENTIAL AMINO ACIDS IN BY-PRODUCTS RECOVERED
FROM FOOD PROCESSING AND TREATMENT WASTES BY COAGULATION WITH CHITOSAN
Essential
ami no acids
Threonine
Valine
Cystine
Methionine
Isoleucine
Leucine
Phenylalam'ne
Tryptophan
Lysine
g amino acid/100 g total amino acids in acid hydrolysate
Coagulated by-product
Egg breaking
waste
4.8
6.1
_f
2.6
5.5
8.8
5.7
_f
5.9
Vegetable b
act. sludge
5.3
6.4
_f
1.6
4.4
7.5
6.9
_f
5.4
Brewery
act. sludge
5.2
7.0
_f
3.5
5.0
8.2
5.3
1.99
4.0
Reference protein
Essential .
FAO pattern0
2.8
4.2
2.0
2.2
4.2
4.8
2.8
1.4
4.2
Milkd
4.57
5.43
4.0
4.28
16.28
5.71
1.71
7.43
Meatd
4.6
3.3
4.2
3.3
12.5
4.6
1.3
8.3
Coor's
BSCPe
6.6
8.3
3.5
6.0
9.5
5.8
5.6
Average of five samples.
Average of two samples.
cAverage of three samples.
dR. Dabbah.20
eBrewer's single cell protein.21
^Destroyed by acid hydrolysis.
9Assayed by microbiological method.12
-------
Table 7. PRELIMINARY RESULTS ON EFFECTS OF CHITOSAN IN RAT DIETS ON
FEED INTAKE, EFFICIENCY, AND BODY WEIGHT3
Chitosan
In diet,
%
0
0.5
1.0
2.0
5.0
Chitosan intake,
g/kg body wt./
day
0.0
0.44
0.91
1.82
4.98
Avg. total
intake, g
757lC
7761
7001
638 1
679 l
Feed .
efficiency
0.3361
0.3251
0.3181
0.3201
0.2882
Avg. final wt.
of animal , g
325. 8 1
323. 41
293. 81'2
294. 61'2
267. 82
Five rats per died fed for 5 weeks on a standard casein diet.
Feed efficiency is g of weight gained per gm of feed consumed.
cValues followed by the same superscript number are not significantly
different at the 1% level of confidence.
41
-------
Table 8. PRELIMINARY STUDY ON PHYSIOLOGICAL EFFECTS OF CHITOSAN
IN RATE DIETS ON LIVER WEIGHT, HEMOGLOBIN, AND HEMATOCRIT*
Chitosan in
diet, %
0
0.5
1.0
2.0
5.0
Liver
Wt., g
14.69lb
14. 361
12. 621'2
11. 772
11. 302
% body wt.
4.501
4.441
4.291*2
3.992
4.221'2
Hemoglobin,
q/100 ml
14. 761
15. 381
15.421
15. 451
15. 391
Hematocrit, %
50. 61
52. 41
53. 3l
52. 31
52. 91
Five rats per treatment fed for 5 weeks on standard casein
diets.
3Values followed by the same superscript number are not
significantly different at the 1% level of confidence.
-------
and hardness of chitosan particles. Chitosan was added to the diets as
solids particles ground to pass a 20 mesh screen. The animals would try
to pick out these particles. In actual use as a coagulating agent,
chitosan will be dissolved in dilute acetic acid for application to food
wastes. Molecules of chitosan which are adsorbed and incorporated into
particles of coagulated solids will be evenly distributed along with
proteins and fats. Thus, the animals will not notice any physical
discomfort due to chitosan particles. The reduction of feed intake
probably contributed to the reduced weight of the animals fed the diet
containing 5 percent chitosan, but the rate of feed conversion by these
animals was also lower than that of controls. Liver weight was reduced
in rats fed diets containing 2 percent or 5 percent chitosan. In the
latter group of animals, the decreased liver size was associated with a
general depression of growth so that liver as a percent of the total
body weight was not different from the controls. In animals fed 2
percent of the polymer in the diet, liver as a percent of the body
weight was lower than the controls. There is no obvious explanation for
this difference.
Arai et al. found that chitosan fed to mice caused no harmful
effects up to 18 grams per kilograms body weight per day. Above this
amount, toxic effects were observed.25 Our experiment with rats
suggests that levels up to 2 percent of chitosan can be fed without
significantly affecting the growth or health of the animal. A
concentration of 2 percent chitosan in the diet is greater than levels
anticipated in commercial use. Coagulated vegetable sludge and brewery
sludge in this study contained 0.3 to 0.4 percent and 0.72 to 0.82
percent chitosan, respectively. If 10 to 20 percent of such a
coagulated by-product is incorporated in an animal feed as one of the
protein sources, then the concentration of chitosan in the feed would be
less than 0.2 percent in even the highest case. No adverse effects due
to 0.5 percent chitosan in the diet have been observed in our
experiments thus far. Significant weight reduction was observed at 5
percent chitosan in the diet, but this is probably 10 to 25 times the
concentrations expected from use of coagulated by-products in animal
feeds. These results on the physiological effects of chitosan are
considered to be preliminary. This experiment is being repeated with
more animals and for a longer period of time.
Our data on the use of chitosan for recovery of coagulated by-
products from food processing wastes and treatment systems have been
summarized and submitted to the Non-Ruminant Branch of FDA as a
preliminary proposal for approval of chitosan as a coagulating agent to
be incorporated into animal feeds as an ingredient of coagulated by-
products.
The estimated supply of activated sludge from the food industry is
quite large. Garner e_t aj^ of the USDA estimated the total production
43
-------
of BOD from food and kindred products to be 4,300 million pounds
annually.26 Assuming 0.3 pounds dry activated sludge will be wasted or
utilized per pound of BOD, then 1,290 million pounds of sludge could be
produced from food and kindred wastes. However, the National Industrial
Pollution Control Council reports 62 percent of cannery waste and 80
percent of dairy products waste are treated in municipal facilities.27
So, if we assume that 25 percent of the total BOD load from the food
industry is treated in private facilities, separate from domestic wastes
so that the activated sludge could be safely utilized as feed
ingredients, the supply of dry sludge would be 322 million pounds (25
percent x 1,290 million pounds).
McWhorter has reported the total BOD load from United States
breweries to be 338 million pounds.28 He estimates the potential supply
of brewery sludge to be 169 million dry pounds. While some of this
supply is now being handled in municipal plants, the recent trend, he
observes, is for breweries to be large in size, located in rural areas,
and to construct and operate their own waste treatment facilities.
The annual supply of chitosan which could be produced in the United
States has been estimated by Peniston to be 10 million pounds.29
Assuming a ratio of 1 percent chitosan to sludge solids, the amount of
chitosan required to condition 322 million pounds of sludge from food
wastes and 167 million pounds of brewery sludge would be approximately 5
million pounds or 50 percent of the annual supply. Thus, it is possible
that chitosan, which is itself derived from shellfish wastes, may serve
a unique function in the recovery of coagulated by-products from food
processing and treatment wastes. Recovery of activated sludge appears
to be one of the most effective uses of chitosan.
ACKNOWLEDGEMENTS
The technical assistance of Will Salter, Jeff Allen, Lanny
Stephens, and Tom Campbell is gratefully acknowledged. The contribution
of R. Caamano and D. Alf in the operation of the Sharpies centrifuge was
essential to the conduct of the experiments on brewery sludges.
Chitosan was obtained from Food, Chemical, and Research
Laboratories, Inc., Seattle, Washington. Other polymers (identified by
prefix) were obtained from the following sources: "Betz", Betz
Laboratories; "Atlasep", Atlas Chemical Corporation; "WT", Calgon
Corporation; "Nation", National Starch and Chemical Corporation; and
"Floe", DuBois Chemicals.
44
-------
This work was supported by the University of Georgia College of
Agriculture Experiment Stations and by the National Sea Grant Program,
U.S. Department of Commerce, Grant No. 04-5-158-4.
45
-------
REFERENCES
1. Peniston, Q. P. and E. L. Johnson. Method for Treating an Aqueous
Medium with Chitosan and Derivatives to Remove an Impurity. U.S.
Patent No. 3,533,940. 1970.
2. Rigby, G. W. Substantially Undegraded Deacetylated Chitin and
Process for Producing the Same. U.S. Patent No. 2,040,879. 1936.
3. Bough, W. A. Reduction of Suspended Solids in Vegetable Canning
Waste Effluents by Coagulation with Chitosan. J. Food Sci.
40:297. 1975.
4. Bough, W. A., Shewfelt, A. L., and Salter, W. L. Use of Chitosan
for the Reduction and Recovery of Solids in Poultry Processing
Waste Effluents. Poultry Sci. In press. 1975.
5. Bough, W. A. Coagulation with Chitosan—an Aid to Recovery of By-
Products from Egg Breaking Wastes. Poultry Sci. In press. 1975.
6. Culp, R. L. and G. L. Culp. Advanced Wastewater Treatment.
VanNostrand Reinhold Company, New York. 1971 p. 258.
7. American Public Health Association Standard Methods for the
Examination of Water and Wastewater, 13th edition. 1971. p. 536-
37.
8. Assoc. Offic. Agr. Chemists. Official Methods of Analysis, 7th
edition. 1950. p. 13, item 2.24.
9. Association of Official Analytical Chemists. Official Methods of
Analysis, llth edition. 1970. p. 123, item 7.010; p. 129, item
7.043; p. 392, item 24.005. 1970.
10. Herbert, P., P. J. Phipps, and R. E. Strange. Chemical Analysis of
Microbial Cells. In: Methods in Microbiology, Volume 5B. Norn's,
J. R. and D. W. Ribbons (eds.). Academic Press, New York. 1971.
11. Moore, S. The Precision and Sensitivity of Amino Acid Analysis.
Chem. and Biology of Peptides. Ann Arbor Sci. Publishers, Ann
Arbor. 1972. p. 629-653.
12. Henderson, L. M. and E. E. Snell. A Uniform Medium for
Determination of Amino Acids with Various Microorganisms. J. Biol.
Chem. 172:15. 1948.
13. Miller, J. Effect of Minor Supplementation of Methiom'ne on Iron
Absorption in the Rat. Nutr. Rept. Intern!. 4:217. 1971.
46
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14. Evelyn, K. A. and H. T. Malloy. Microdetermination of Oxyhemo-
globin, Methemoglobin, and Sulfhemoglobin in a Single Sample of
Blood. J. Biol. Chem. 126:655. 1938.
15. Johnson, E. L. Personal communication. Food, Chemical, and
Research Laboratories. Inc. January 23, 1975.
16. Perceval, P. M. Personal communication. Marine Commodities
International, Inc. January 8 and 14, 1975.
17. Bough, W. A., W. L. Brown, J. D. Porsche, and D. M. Doty.
Utilization of Collagenous By-Products From the Meat Packing
Industry: Production of Single-Cell Protein by the Continuous
Cultivation of Bacillus megateriurn. Appl. Microbiol. 24:226.
1972.
18. Tannenbaum, S. R. Factors in the Processing of Single-Cell
Protein. In: Single-Cell Protein. Matels, R. I. and S. R.
Tannenbaum (eds.). The M.I.T. Press, Cambridge. 1968. p. 343.
19. Enebo, L. Single-Cell Protein. In: Evaluation of Novel Protein
Products. Bender, A. E., R. Kihi berg, E. Lofguist, and L. Munck
(eds.). Pergamon Press, New York. 1970. p. 93.
20. Dabbah, R. Protein from Microorganisms. Food Technol. 24:659.
1970.
21. Windell, J. T., R. Armstrong, and J. R. Clinbell. Substitution of
Brewer's Single Cell Protein into Pelleted Fish Feed. Feedstuffs.
May 20, 1974. p. 22.
22. Greenfield, C. Apparatus and Process for Dehydrating Waste Solids
Concentrates. U.S. Patent No. 3,323,575. 1967.
23. Damron, B. L., A. R. Eldred, S. A. Angalet, J. L. Fry, and R. H.
Harms. Evaluation of Activated Citrus Sludge as a Poultry Feed
Ingredient. Proc. Fifth Natl. Symp. on Food Processing Wastes.
1974. p. 142.
24. Taylor, J. C. Personal communication. Division of Nutritional
Sciences, Bureau of Veterinary Medicine, U.S. Food and Drug
Administration. May 13, 1974.
25. Arai, K., T. Kinumake, and T. Fujita. Toxicity of Chitosan. Bull.
Tokai Reg. Fish. Res. Lab. 56:89. 1968.
26. Garner, R. G., G. J. Mountney, and S. E. Zobrisky. Agricultural
Processing Wastes: A Review. Presented before Food Science and
47
-------
Technology Section, 68th Annual Meeting Assoc. of Southern
Agricultural Workers. 1971.
27. National Industrial Pollution Control Council. Pollution Problems
in Selected Food Industries. U.S. Government Printing Office,
Washington. 1971.
28. McWhorter, T. R. Wastes and Wastewater Abatement Practices in the
Unites States Fermentation Beverage Industries. Presented at the
Second International Congress on Industrial Wastewater and Wastes,
Stockholm. February 1975.
29. US Environmental Protection Agency. Development Documents for
Effluent Limitations Guidelines and Standards of Performance for
the Catfish, Crab, Shrimp, and Tuna Segments of the Canned and
Preserved Seafood Processing Industry Point Source Category. EPA-
440/l-74-020a. 1974. p. 222.
48
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DOUBLE-DIP CAUSTIC PEELING OF POTATOES
C. C. HuxsoTl*
M. L. Weaver*
R. P. Graham*
INTRODUCTION
In order to improve the overall efficiency of lye peeling, we have
examined the effects of different procedures of lye application.
Earlier work,1'2 which resulted in a reduction of lye requirements for
peeling, introduced some form of heat, such as high pressure steam or
infrared heat to make a relatively small amount of absorbed caustic more
effective. However, with the recent increases in energy costs, and
perhaps limited availability of energy, a mere substituion of heat for
lye may not improve overall efficiency. Our objective in the work
described here was to develop procedures for applying caustic to
potatoes, and other fruits and vegetables, so that a given amount of
absorbed caustic would be more effective for peeling, without requiring
additional heat input.
In the initial development of the dry caustic peeling process,2 we
obtained the curves shown in Figures 1 and 2. Figure 1 depicts caustic
uptake as a function of immersion time in the lye solution for several
lye concentrations. The curves indicate a lag period followed by a
rapid, almost linear, rate of caustic uptake. Figure 2 shows peel loss
as a function of the hold time between lye immersion and infrared
application in the standard dry caustic peeling process. Peel loss
continues to increase with hold time for holding periods of at least 15
minutes.
From these two figures we intuitively reasoned that caustic first
modifies the suberized layer of the potato, making it more penetrable
for caustic diffusion, and subsequently rapidly attacks the underlying
*Western Regional Research Center, Agricultural Research Service, US
Department of Agriculture, Berkeley, California 94710.
-------
en
o
0.6
UJ
O
o
Q.
X 0.4
O
O
O
I 0.2
40
20% NaOH
I
1
13%
NaOH
1
120 200
DIP TIME (Sec.)
280
Figure 1. NaOH absorbed by US No. 1 Russett potatoes in 170 F lye.
-------
90 SEC. DIP
(0.33# NaOH/100# POTATOES)
60 SEC. DIP
(0.25# NaOH/100# POTATOES)
45
(0,
SEC. DIP
23# NaOH/100# POTATOES)
I I I
2 6 10 14
HOLDING TIME (Min.)
18
Figure 2. Effect of holding time at ambient temperature.
-------
potato flesh, resulting in the rapid caustic uptake. It was also
evident that absorbed caustic continued to attack the potato tissue even
though the potatoes were held at ambient temperature.
We, therefore, concluded that a peeling process would be most
efficient in the use of caustic when the caustic applications are
staged, i.e., one to modify the outer suberized layer and one to attack
the underlying tissue, with holding periods following each application
to maximize the effects of the absorbed caustic. Such a process is
diagrammed in Figure 3.
METHODS
Individual potatoes were washed, weighed, and impaled on stainless
steel spits. Caustic solutions were made to given concentrations using
analytical reagent grade sodium hydroxide pellets (minimum NaOH assay 98
percent). Approximately seven pounds of a given solution were placed in
a stainless steel pot which was heated by an electric hot plate.
Calibrated dial thermometers were used to indicate the solution
temperature. When the desired immersion temperature was reached, the
impaled potito was placed in the solution and the spit was rotated to
thoroughly stir the solution. The temperature was controlled manually.
Following immersion for the specified time, the potato was held on the
spit and exposed to the ambient conditions of the laboratory, where the
temperature was usually 70 to 75 degrees F. Immersion and holding times
were measured with a stop-clock.
Following a given series of immersions and holding periods, the
potatoes were either peeled or subjected to infrared heat. When
infrared heat was used, the impaled potato was rotated under a gas-fired
infrared burner with the nearest surface of the potato two inches from
the radiating ceramic mantle. The irradiating surface temperature was
about 1,600 degrees F.
Peeling was accomplished by hand brushing under a small flow of
water or by use of a small mechanical laboratory dry peeler2 utilizing
rotating rubber-tipped rolls. When the mechanical peeler was used, the
potatoes were subsequently hand brushed under a small flow of water to
remove a small amount of remaining loose peel material.
The peeled potatoes were weighed to determine the amount of
material removed as peel, and a visual inspection was made to ascertain
the degree of "heat ring" formation and the overall peeling quality.
Lye uptake was measured by a previously described technique2 in
which about five to ten pounds of caustic treated potatoes are placed in
52
-------
WASHED POTATOES
i
CAUSTIC IMMERSION I
1
HOLD PERIOD I
I
CAUSTIC IMMERSION II
I
HOLD PERIOD II
1
INFRARED HEAT APPLICATION
(OPTIONAL)
I
PEEL
Figure 3. Flow diagram of double-dip peeling process.
53
-------
a known volume of standard dilute acid. After the caustic in the
potatoes has had time to react with the acid (about 15 minutes), an
aliquot of the acid solutions is taken. Back titration with sodium
hydroxide then determines the quantity of acid neutralized by the
caustic on the potatoes. Thus, the quantity of caustic on a given
weight of potatoes is determined.
Because potatoes, even of the same variety, are known to vary
widely in their peeling characteristics, due to variations in culture
and storage, each series of tests was made with potatoes from the same
lot which were hand selected to provide uniformity of size, shape, and
peel characteristics. All results reported here were obtained from
Russet-Burbank potatoes.
RESULTS
Figure 4 shows the effect of the hold period between the two
caustic applications on the peel loss for several combinations of
caustic treatments. The upper curve respresents 8 percent NaOH at 88
degrees C for 30 seconds in both the first and second dip, while the
bottom curve represents a 5 percent NaOH solution at 88 degrees C for
both 30-second dips. A zero hold time thus corresponds to one
continuous dip of 60 seconds. The middle curve represents an 8 percent
NaOH solution at 88 degrees for 30 seconds in the first dip and a 5
percent NaOH solution at 88 degrees C for 30 seconds in the second dip.
To avoid dilution of the first dip caustic by the lower second dip
caustic, a minimum hold time of five minutes was used. All curves shown
in Figure 4 were obtained with a one-minute infrared heat application.
Figure 5 depicts peel loss as a function of infrared exposure time
for two caustic treatments. The upper curve represents a double dip
treatment—45 seconds immersion in 10 percent NaOH at 88 degrees C, a
15 minute ambient hold, a 45 second immersion in 5 percent NaOH at 88
degrees C, and a three minute ambient hold. The lower curve represents
a single 60-second immersion in 10 percent NaOH at 90 degrees C followed
by a three-minute ambient hold, which is typical of the caustic
treatment used in standard infrared dry caustic peeling. Caustic uptake
for the double-dip treatment was 0.066 pounds NaOH per 100 pounds
potatoes, and the uptake for the single dip was 0.088 pounds NaOH per
100 pounds potatoes.
54
-------
01
Oi
IMMERSION I HOLD I IMMERSION TL HOLD E
VARIABLE
30 SEC
5%NaOH
88°C
30 SEC
8%NaOH
88°C
30 SEC
30 SEC
5%NaOH
88°C
VARIABLE
30SEC
5%NaOH
88°C
30SEC
0-08%NaOH VARIABLE 8% NaOH
88°C 88°C
15
3MIN
AMBIENT
3MIN
3MIN
IR
1MIN
1MIN
1MIN
HOLD PERIOD I (MINUTES)
Figure 4. Peel loss versus hold period between caustic immerisions.
-------
Ul
Oi
IMMERSION I HOLD I IMMERSION H HOLD H
15 MIN 45 SEC 3 MIN
(ambient) 5% NaOH (ambient)
88°C
45 SEC
10% NaOH
88°C
60 SEC
10% NaOH
93°C
15
3 MIN
(ambient)
IR
VARIABLE
VARIABLE
0.066 Ibs.
Potatoes
0.088 Ibs. NaOH/100 Ibs.
Potatoes
60 90
IR EXPOSURE TIME (SECONDS)
Figure 5. Peel loss versus infrared exposure time for double-dip
and standard lye applications.
-------
DISCUSSION
From Figures 4 and 5 it is evident that the double-dip treatment
has a substantial effect on peel loss. Figure 4 shows that during the
hold period between the two dips, the caustic absorbed in the first dip
is in fact modifying the peel surface so that the second dip becomes
more effective in removing tissue. For the lower curves, where only 5
percent NaOH is used in the second dip, peel loss increases nearly
linearly with hold time for a hold period up to at least 30 minutes.
When 8 percent NaOH is used in both dips, as in the upper curve of
Figure 4, the effect of the hold time diminishes after about 15 minutes.
The improved efficiency of the caustic in a "double-dip" treatment
versus a standard single dip treatment is evident from Figure 5. Even
though the total caustic uptake is less for the double-dip system, the
peel removed is greater than for the single dip regardless of the amount
of infrared heat applied. In fact, the peel loss without infrared heat
in the double dip treatment corresponds to the peel removed in a single
dip treatment followed by 60 to 90 seconds of infrared irradiation.
Also, the effect of infrared heat levels out at about 60 seconds of
irradiation for the double-dip system, but for the single dip system the
peel loss continues to increase for up to at least 90 seconds of
infrared irradiation.
Of course, the object of a good peeling process is not to obtain
high peel losses, per se. The results given in Figures 4 and 5 only
show the improved efficTency of a given quantity of lye when the double-
dip system is used. Good peeling occurs when, for a given amount of
peel loss, all eyes and minor surface defects are removed without
excessive development of surface "heat ring". Figure 6 is a photograph
of potatoes peeled at various stages of the double-dip method. The
final peeled potato is free of all eye tissue and surface defects and
essentially no heat ring has developed.
CONCLUSIONS
Our results show that the double-dip caustic peeling system can
effectively increase peeling efficiency without the use of additional
energy input. In fact, the caustic efficiency for the double-dip system
appears to be equivalent to the caustic efficiency of the single dip
system combined to 60 to 90 seconds of infrared heat. Thus, the double-
dip system offers a means of avoiding the high energy consumption of the
infrared system. Moreover, a "rule-of-thumb" in the potato industry is
that about one pound of caustic is required to peel 100 pounds of
potatoes in standard lye peelers vlthout infrared. Our data show that
caustic usage with the double-dip system is 10 percent or less of this
57
-------
01
oo
5% NaOH
10% NaOl
H 93°C
30 sec
3 min
ambient
IMMERSION I
HOLD
IMMERSION D
+ HOLD D
Figure 6. Photograph of potatoes peeled at various stages of double-dip
process (no infrared heat).
-------
amount. Even if commercial installations of the double-dip system
require two or three times as much caustic as our idealized laboratory
system, substantial caustic savings may be realized. Because lye is
made through the energy intensive process of electrolysis and
evaporative concentration, reductions in caustic usage indirectly reduce
energy requirements for the system as a whole.
59
-------
REFERENCES
1.. Adams, H. W., F. D. Mickey, and M. J. Willard, Jr. Lye Pressure
Steam Peeling of Potatoes. Food Techno!. 14:1-3. 1960.
2. Graham, R. P., C. C. Huxsoll, M. R. Hart, M. L. Weaver, and A. I.
Morgan, Jr. Dry Caustic Peeling of Potatoes. Food Techno!.
23(6):61ff. 1969.
60
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EGG BREAKING AND PROCESSING WASTES CONTROL AND TREATMENT
W. J. Jewell*
W. Siderewicz*
R. C. Loehr*
R. R. Zall**
0. F. Johndrew, Jr.***
H. R. David*
J. L. Witherow****
INTRODUCTION
Control of wastewaters from many food processing facilities are
complicated because of their location and the highly contaminated wastes
which they produce. For many types of foods it is necessary to locate
the processing facilities near the source of the raw material. This
often means that the facility will be located in rural areas where the
pollution control facilities may have difficulty handling complex food
wastes. Due to lower tax bases and less organized government structures
in small communities, the organizational structures required to respond
to pollution control planning may not be effective. The egg processing
industry is an example of a food processor that is often located in
rural areas and may have diffucult wastewater control problems.
The new federal pollution control laws require that all industries,
including food processors, assume responsibility of achieving a high
degree of control over their wastes in the near future. This
responsibility can be met by using a number of alternatives, including
efficient treatment and direct discharge of the purified effluent,
*Department of Agricultural Engineering, Cornell University, Ithaca, New
York.
**Department of Food Science, Cornell University, Ithaca, New York.
***Department of Poultry Science, Cornell University, Ithaca, New York.
****US Environmental Protection Agency, Corvallis, Oregon.
61
-------
discharge elimination using land disposal of the wastes, no treatment
and discharge to a municipal system, or treatment to a level comparable
to domestic sewage and discharge to a municipal treatment facility. The
U.S. Environmental Protection Agency (EPA) has specified the discharge
requirement that must be met by many industries for two future time
periods. Wastewater control technology equivalent to using the "best
practicable control technology currently available (BPT)" is to be in
use by July 1, 1977; while the pollution control equivalent to the "best
demonstrated technology economically achievable (BAT)" must be in use by
July 1, 1983. Preliminary discussion effluent guidelines have recently
been issued for the egg breaking industry.
In order for the many food processing industries to meet the
allowable discharge quantities, it is often necessary to reduce the
effluent BOD concentration from several thousand milligrams per liter to
20 to 40 milligrams per liter. This level of control is difficult and
expensive to achieve by wastewater treatment processes. The obvious
alternative to complete "end of pipe" treatment is to prevent the
pollutant loss through in-plant control. Successful in-plant control of
wastes can result in capture of valuable food products which can be
translated into a method of minimizing the costs of pollution abatement.
A two-phased approach to determine the maximum waste that could be
conserved by in-plant control followed by treatment of the resulting
wastewater was the approach of this study.
OBJECTIVES
This study of the egg breaking industry is divided into three
sections: a review of the characteristics of the industry as a whole,
characterization and control of wastes in five egg breaking plants, and
investigations into the treatability of wastewaters from egg breaking
facilities. The data is 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 evaluated, 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.
It was the general goal of this study to provide an overview of the
industry which would include practical and inexpensive in-plant waste
62
-------
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 wastewaters
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 wastewaters to
various levels of contamination.
For further details see reference 1.
THE EGG BREAKING INDUSTRY
The number of egg breaking plants and the growth of the industry is
summarized in Figure 1. The largest number of facilities was 477 in
1949 reflecting the influence of the Second World War. Except for the
peak during the war years, this industry has grown at a linear rate of
about 12 million pounds per year of increased production capacity.
However, use of liquid egg products in quick food preparation and
development of new products could have a significant effect on the
future growth rate of this industry.
Production Rate Variability
In considering pollution control in this industry, one of the most
important characteristics is the high variability of production rate.
In its early development it was essentially a scavenger industry using
surplus eggs at times of the year when shell production was depressed.
Although the industry presently competes for good quality eggs
throughout most of the year or imports the needed amounts, it is still
highly susceptible to availability of supplies. The data shown in
Figure 2 illustrates this variability in the United States over a three-
year period and Figure 3 shows this pattern for one of the larger
facilities sampled in this study. The whole industry faces shortages of
63
-------
2000
500
OJ
1920 1930 1940 1950 I960
YEAR
1970
1980
1990
Figure 1. Annual US production of liquid egg products (dried, frozen
and those used for immediate consumption) and number of plants
under USDA inspection.
-------
Oi
01
TIME OF YEAR, months
Figure 2. Monthly variations in US egg product production.
-------
os
os
o
E
m
O
o
UJ
I-
<
QC
O
ui
O
o
oc
o
ui
50,000
40,000
30,0001
20,000
10,000
DATA FROM PLANT E
'72
I I I
I I I I I I I
1 I I I
I
'73
I
'74
II
TIME OF YEAR , months
Figure 3. Monthly processing rate of eggs at Plant E.
-------
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 effecient
operation at only half the waste load during the period November through
January.
The egg industry is, financially, the most important of the various
poultry enterprises. In 1973 marketing of eggs accounted for 50 percent
of the total $6.5 billion gross national income associated with all the
poultry industry (eggs, broilers and turkeys).2 Of the total eggs
produced in the United States in 1972, 11 percent of the shell eggs were
broken for use in producing egg products (liquid, frozen and dried
eggs). The value of liquid eggs produced in the United States in 1965
was $195 million.3
Nearly half of all egg breaking facilities in the United States, or
about 100 facilities, are presently plagued by some type of wastewater
disposal problem.11 Although the industry is relatively small it is
distributed throughout the country with at least one plant in most
states. However, very little was known about the waste characteristics
of this industry and the capability of controlling the wastewaters.
Although the managers of several facilities estimated that their
egg losses were between 6 percent and 10 percent of the processed egg,
they did not know the impact of this loss on the pollution control
facilities, the economic impact of this loss on their operation, or the
potential for minimizing these losses.
WASTEWATER CHARACTERIZATION
Facility Location and Approach
Five facilities were sampled—three in New York State and one each
in Georgia and Arkansas. The three New York plants were studied in
great detail. A minimum of six days of 24-hour sample collections were
used in the New York State facilities to enable reliable estimations of
the waste loads before and after in-plant modifications. Two days of
sampling were used to develop data for each of the two plants outside
New York. Eighteen days of sampling provided information on waste
characteristics for the most intensively examined facility (Plant A).
67
-------
Project Approach
All plants were examined for total plant losses as well as unit
process losses in order to identify in-house sources of waste. Methods
to reduce wastes through in-plant modifications were suggested and
implemented. Later, the sites were sampled again to measure the effects
of the changes through repeated plant wastewater surveys.
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 1.
Independent of the plants' size, it was observed that the plants' layout
and mode of operation were nearly identical. The flow diagram of an egg
breaking operation in Figure 4 illustrates the various operations
involved in preparing 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.
Upon reaching the washer, eggs are manually loaded onto a conveyor
belt. At this point the inspector removes any "leakers" which are
broken shell eggs 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. Most washers contain
about a 50 gallon liquid volume which is continually recycled for a four
hour period and then drained to the sewer system. Once the eggs have
passed through the scrub brushes they are conveyed above a series of
briliant lights for inspection in a candling operations. Inspectors
remove "leakers", blood spot, and 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 larger containers for pet food
products.
Breakers in plants cooperating with this study operated at a rate
of about 40 cases per hour which means that the employee at these
machines examined eggs at four per second. The employee operating the
breaking machine has the responsibility to (1) remove eggs containing
blood spots, (2) remove spoiled eggs and cups into which they were
broken, (3) manually 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 stainless steel cups to a full down position to be
washed when they appear dirtly or when no egg was released into the
cups. If the U.S. Department of Agriculture's (USDA) inspector notices
68
-------
Table 1. SIZE AND TYPE OF EGG PROCESSING PLANTS SURVEYED
Plant
Identification
A
B
C
D
E
Number
of egg
washers
1
2
1
12
8
Number
of egg
breakers
1
3
1
12
8
Number
of egg
pasteurizers
1
1
1
3
2
Type of product
processing
Frozen yolk,
white and
whole egg
Frozen yolk,
white and
whole egg
Frozen whole
egg, liquid
whole egg
(bulk tank)
Frozen whole
egg, dried,
yolk and
white and
whole egg
Liquid, yolk,
white and
whole egg
(bulk tank
transport as
liquid)
69
-------
DAMAGED CARTOONS
. _ DROPPED AJ^-
-
-*-
^
^*"
k
[
1
QTR A IKIFR
1
HOLDING
TANK 40°F
1
i
BLEND
TANK
1
DA eTT IIDI7CTO
rAb 1 1 UKI£c.R
, 1
| CAN OFF
CO C C 7 C D
rnt b^cn
^
^
=
— A
uw cui DI_C. ; —
INEDIBLE
EGGS
• DRIED
NIMAL FOOD
RECOVERY
DISTRIBUTION
Figure 4. Flow diagram of product in egg breaking facilities.
70
-------
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.
Egg meats from the breaking machine 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 produce does not possess obnoxious
odors, sugar, salt and other condiments may be added to the product.
The contents are drained through a coarse screen filter which retains
shell fragments and the egg's chalazae.
The pasteurized product is cooled to 4.4 degrees 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 kilogram (30 pound) cans, 1.9 liter (1/2
gallon) cartons or 4.5 kilogram (10 pound) plastic bags. Filled
containers are prestacked on pallets to be placed in the freezer area.
The daily clean-up operations are some of the main sources of
wastewater generation. Before work starts in the morning, the resident
USDA inspector examines all machinery and its surroundings to be sure it
is thoroughly cleaned and free of egg solids from the previous day's
work. 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. Frequently, substantial amounts
of egg products that remain in the vats, filters and pipes 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 production 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.
Sampling Site Preparation
Frequently, food plants use municipal water for the majority of
their water and simultaneously supply its refrigeration plant with
private unmetered well water for cooling or wash-up water. Since
detected 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
71
-------
carried wastes and the floor drains (except employee restrooms),
excavation was made and a weir box was fitted into position.
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. An automatic sampler was also set to collect and combine nine
equal sized samples per hour. 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
according to time only. In most cases the differences between values
were less than 20 percent, even for the high or low values. The
difference between the average concentrations was usually less than 10
percent. All values will be from the flow composited samples unless
noted otherwise. All samples were stored on ice to minimize biological
degradation, and chemical analyses were usually completed within 24
hours.
Example fluctuations of effluent wastewater and BOD5 are shown in
Figure 5 for one facility. The data shown in Table 2 summarizes the
average wastewater characteristics before and after in-plant
modifications were adopted for waste conservation. Methods of in-plant
wastewater reduction will be discussed later. These data are averages
of up to 19 days of 24-hour composite samples obtained from between 20
and 30 subsamples. The variation of the pollutants from Plants A, B and
C are shown in Table 3. In general, the wastewaters are highly
contaminated with organics with BOD5 concentrations as high as 11,500
milligrams per liter. The ratio of BOD5 to total COD averaged 0.60.
The concentration of phosphorus indicated that the higher yield
biological treatment processes might be nutrient limited. Additional
alkalinity may be required to support the inorganic carbon demand if the
organic nitrogen is nitrified.
Wastewater Sources and In-Plant Control
After completion of the effluent analysis, a detailed in-plant
sampling was conducted to determine the source of pollutants. This
included collecting weighted composite samples of the egg washer
overflow and sump contents, continual overflow from the egg breaker and
flushing of vats, tanks, strainers, piping and pasteurizer. Other
sources of wastes included rejected inedible eggs from the washer and
breaker operations that were not deposited in the proper receptacles,
egg product dripping from the breaking machine, malfunctioning 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 were referred to as floor losses. Examples
of the comparison of the total to various sources is shown in Figure 6.
72
-------
2000
— 200
o
o>
yj" 1600
-q
co'
cc.
UJ
<2
tr
<
X
o
CO
cr
LU
UJ
1200
800
400
8 9 10 II 12 I 234567
AM PM
TIME OF DAY , hours
10 II
Figure 5. Example of water usage and organic losses (BOD5) in Plant B
before in-plant modifications.
-------
Table 2. AVERAGE EFFLUENT WASTEWATER CONCENTRATIONS BASED ON 24-HOUR COMPOSITE SAMPLES BEFORE
AND AFTER IN-PLANT MODIFICATIONS FOR WASTE CONTROL9
rfk
Facility
Before
A
B
C
After
A
B
Total
solids
5,580
5,450
-
2,240
4,360
Suspended
solids
1,410
930
-
520
640
Total
kjeldahl
nitrogen
as N
520
430
-
180
310
Ammonia
nitrogen
as N
4.9
8.3
-
2.9
1.4
Total
phosphorus
41.2
13.7
-
11.8
10.0
BOD5
6,400
4,660
-
1,650
3,660
COD
10,500
7,760
-
3,200
6,870
Total
alkalinity
as CaC03
380
390
-
310
375
All values in mg/1
-------
Table 3. MAXIMUM RANGE OF POLLUTANTS MEASURED IN EGG BREAKING
WASTEWATERS IN PLANTS A, B AND Ca
Parameter
Range of Value
Total solids
Suspended solids
Totak kjeldahl nitrogen, as N
Ammonia nitrogen, as N
Total phosphorus, as P
Total alkalinity as CaC03
BOD 5
COD
1,400-5,910
180-1,750
84-630
Trace-17.9
6.0-59.4
260-1,160
k
590-11,500
1,600-17,900
All values in mg/1.
75
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TOTAL PLANT
WASTE
WASHERS BREAKERS TANKS, PIPES. FLOOR LOSSES
ETC.
Figure 6. Unit operations contribution of waste of egg breaking wastes
before in-plant modification for waste reduction in Plant A.
-------
Although the egg washers contribute only 5 to 10 percent of the plants
total wastewater, the BOD5 loss represented from one quarter to one half
the total plant loss. Since the total volume of egg washing water in a
medium sized facility (three breakers, for example) would be about 500
gallons per day, it seemed appropriate to consider removing this entire
stream from the sewer. The water use shown in Figure 6 for the egg
breaking machine is excessive due to malfunctioning of a float valve. A
breakdown of the relative quantities of organic wastes and their sources
is illustrated in Figure 7.
In-Plant Modifications
Informing management of the weight of BOD5 lost in their operation
provides little understanding or motivation for decreasing the losses.
A more effective approach is to relate BOD5 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 of all materials
around a facility indicates the relationship of various losses to the
quantity of final product. The mass balance for Plant A shown in Figure
8 is an average of three separate days of sampling in which the total
weight of material passing out of the plant was 5 percent less than the
measured total input weight. The losses of egg product to the sewer
represent a daily loss of about $440 in revenue for Plant A. This was
an important observation since this magnitude of loss represents a
singificant portion of the income of the plant.
Analysis of the waste source survey resulted in developing 13 steps
that could be taken to control wastes by in-plant management (Table 4).
Although the degree of adoption of the steps shown in Table 4 could not
be determined, Plants A, B and C attempted to implement those identified
as 2, 3, 4, 6, 11 and 13. In essence, each plant manager adopted the
changes which he could implement quickly at a low cost. It was
estimated that the cost of the plant modifications was less than $300.
The egg washwater was segregated from the sewer and placed in a sanitary
landfill along with the shells.
The resulting change in concentration of some pollutant was
presented earlier in Table 2. However, the reduction of wastes must be
determined using the total weight losses. For Plant A, the percent of
material lost to the sewer was about 6.3 percent of processed egg before
efforts were made to control waste losses. This was reduced to an
average loss of 1.7 percent using in-plant management (see Table 5).
The total amount of edible egg liquid did not change, but the animal
food recovered increased by nearly 5 percent. It was estimated that the
degree of waste control achieved in Plant A represented about 80 percent
of the control that is practically feasible. A summary of all water and
BOD5 losses before and after modification is shown in Figure 9. The
77
-------
-q
00
EGG WASHER
SHELL AUGER
DRIPPINGS
MISCELLANEOUS
FLOOR LOSSES
PASTEURIZER STARTINGS
AND STOPS, AND PIPE
FLUSHING
INEDIBLE EGG DISPOSAL
AT CANDLING OPERATION
Figure 7. Approximate sources of organic waste loads generated in egg
breaking facilities.
-------
EGGS BROKEN
CEGGS & SHELL)
5952 kg (13,119 Ib)
100%
~q
to
EGG
PROCESSING
PLANT
LANDFILL
\ SHELLS 658kg(l443lb)
j ADHERING
( EGG PRODUCT
12.2 %
INEDIBLE
EGG PRODUCT
3.4%
213 kg (470 Ib)
EDIBLE FOOD 4flqfi kn / in Ton
PRODUCT 4896 kg (10,790
78.2%
L°SSESwlRT° 394 kg (864 Ib)
6.3%
Figure 8. Mass balance of egg materials in processing Plant A before
waste control modifications.
-------
Table 4. 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
system.
3. Efficient collection of discarded eggs.
4. Frequest adjustment of brushes in washers to minimize breakage.
5. Frequent inspection of egg breaking carrying trays to insure
efficient collection.
6. Collection of she! 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 egg chalazaes and gelatinous egg solids from 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.
80
-------
Table 5. COMPARISON OF MASS BALANCES OBTAINED FOR EGG BREAKING
OPERATIONS IN PLANT A BEFORE AND AFTER MODIFICATIONS
FOR WASTE CONTROL
Modifications
Before
After
Fate of input
Fraction of total throughput, %
Shells
and
adhering
al bumen
12.2
12.2
Animal
food
3.4
7.9
Edible
food
78.2
77.3
Loss
to
sewer
6.3
1.7
81
-------
UJ
< c
OC Q>
UJ N
UJ^
s°
£ "
UJ
CO
£
1.2
0.8
BEFORE MODIFICATION-
AFTER MODIFICATION
1.2
0.8
0.4
IOOO 2000 3000
(CASES PER DAY)
45,000 90,000 135,000
(TOTAL EGG, Ib per day)
PRODUCTION CAPACITY
o
UJ
CO
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UJ
o
o
cc
a.
o
o
UJ
XI
CO
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S5
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AFTER MODIFICATION
I
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CO
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(CASES PER DAY)
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(TOTAL EG6, Ib per day)
PRODUCTION CAPACITY
Figure 9. Summary of the average organic and water volume losses before
and after plant modifications for waste control.
82
-------
average quantity of eggs lost in all facilities before modification was
about 12.5 percent of the liquid egg processed, whereas, average losses
after use of in-plant management was 6.4 percent. In-plant control of
wastes were capable of decreasing water useage by about 26 percent and
BODs reduction by more than 50 percent.
TREATABILITY
Treatability studies were conducted on wastewaters from egg
breaking operation in New York State. Samples were obtained from two
plants (Plant A and Plant B) after first reducing the plants' waste
loads through in-plant modifications.
In considering possible solutions to the effluent problem, the
small size of each individual facility must be kept in mind. The
largest facility has a production capacity less than 150,000 dozen per
day (about 180,000 pounds per day) and a total design waste flow of less
than 200,000 gallons per day. This flow is equivalent to the sewage
from a community of 2,000 people. It is especially difficult to provide
an efficient and inexpensive waste treatment system for such small but
highly contaminated waste flows. Thus, limitations of this portion
included development of efficient, inexpensive and simple waste
treatment approaches that could provide varying levels of treatment.
Initial emphasis was placed on the use of aerobic system such as
aerated lagoons and activated sludge because it was felt that
disagreeable 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.
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 a 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 examined.
Methods and Procedures
The aerated lagoons were simulated using a 20 liter reactor with a
surface area of 2.5 square feet. The system was innoculated with mixed
83
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liquor from a local activated sludge sewage treatment facility. The
lagoons were fed on a fill and draw basis, ususally once per day, with
distilled water added to account for evaporation losses. The multiple
compartment units were the same as the aerated lagoons with baffles
added. The activated sludge system consisted of a 5.5 liter reactor
followed by an 800 ml clarifier. Substrate was fed continuously to the
activated sludge model over a 16-hour period. Solids were wasted from
the clarifier in order to maintain a specific solids retention time
(SRT).
The rotating biological contactor (RBC) was made up of four
sections with a total of 36 polyethylene discs (effective surface area
of 250 square feet). The liquid volume was 136 liters. This unit was
located at Plant B and fed continuously while the egg breaking facility
was in operation.
The anaerobic-aerobic series lagoon treatment was tested using a
volume of 30 liters in the first unit and a second unit with a hydraulic
detention period of six days. Feed for all units was obtained from
either Plant A or B after in-plant modifications had been completed.
All feed samples were composited over an entire working day.
The egg processing wastes which were fed to the various treatment
processes and the resulting treated effluent were analyzed for a number
of characteristics. Total solids, total alkalinity, ortho-phospate and
BOD5 determination were made in accordance with procedures outlined in
Standard Methods.5 Ammonia and Kjeldahl nitrogen were determined as
describedByPrakasam et al.6 Both nitrogen analyses are identical 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. 7
Additional analyses performed included suspended solids, by use of
a Millipore filter apparatus and #9-873B (2.4 centimeters in diameter)
Reeves Angel glass fiber filters. Dissolved oxygen determination and
oxygen uptake 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 turbidmeter.
Aerated Lagoons
Examples of the performance of the aerated lagoons is shown in
Figure 10. The BOD5 loading rate on the 30-day HRT aerated lagoon was
120 pounds per acre per day or about 8 pounds per 1,000 feet of reactor.
Nitrification was more than 90 percent complete, with from 0 to 4.6
milligrams per liter NHa-N and 0.1 to 4.5 milligrams per liter N02-N
appearing in the effluent. Oxygen uptake rates decreased from 25.3 to
84
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HRT= 30 DAYS
INFLUENT TOTAL COD
EFFLUENT TOTAL COD
EFFLUENT SOLUBLE COD
HRT = 20 DAYS
INFLUENT TOTAL COD
EFFLUENT TOTAL COD
EFFLUENT SOLUBLE COD
HRT= 10 DAYS
INFLUENT AS ABOVE
EFFLUENT TOTAL COD
EFFLUENT SOLUBLE COD
^ 9000H
o>
Q
O
O
10 15 20 25 30
OPERATION TIME, days
Figure 10. Aerobic lagoon treatment of total egg breaking wastewater
from Plant B at 20°C.
85
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7.0 milligrams per liter per hour as the hydraulic retention period
increased from 10 to 30 days. The aerated lagoons were capable of
reducing a total influent COD ranging from 4,000 milligrams per liter to
greater than 6,000 to a soluble effluent less than 700 milligrams per
liter at all three hydraulic retention periods. The effluent from all
units was characterized by fine nonsettling suspended solids (SS)
varying from 560 to 1,300 milligrams per liter. The SS in the effluent
imparted a highly turbid yellow appearance to the effluent. Even though
these results indicate that this process is capable of soluble COD
removal efficiences greater than 90 percent, the effluent quality will
probably not satisfy most discharge requirements.
Graphical kinetic analyses were conducted to determine the
substrate removal coefficient, K, base 10, COD basis at 20 degrees C.
For substrate from Plant A and B, the removal coefficient was 0.76 day"1
(least square regression coefficient r = 0.90) and 0.58 day"1 (r =
0.97), respectively.
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
longer than four day. The data shown in Figure 11 illustrates that the
effluent quality was similar to the effluent from the aerated lagoons.
The sludge in these units settled poorly and high effluent
tubidities (70 to 100 Jackson Turbidity Units, JTU) indicated that this
process would be a poor choice for the treatment of egg breaking wastes.
Data accumulated from the bench scale operations were used to
estimate yield, endogenous respiration and oxygen utilization
coefficients. Yield coefficients were 0.245 and 0.300 mg cells per mg
COD removed (soluble COD basis), endogenous respiration coefficients
were determined to be 0.060 and 0.043 day"1, and oxygen use coefficients
were 0.583 for a1 and 0.164 day1 for b'.
The activated sludge process is capable of producing an effluent
suitable for discharge to a joint treatment system without resulting in
a surcharge for excessive oxygen demand or suspended solids. However,
problems with settleability of the sludge should be anticipated with
this system.
86
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oo
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5000 —
4000
o>
E
Q
O
3000
2000
INFLUENT TOTAL COO
EFFLUENT SOLUBLE COD
EFFLUENT TOTAL COD
1000
I I I I
8
12 16 20 24
OPERATION TIME, days
28 32
Figure 11. Activated sludge treatment of wastewaters from Plant B at 20°C.
-------
Rotating Biological Contactor
A final aerobic treatment process investigated was the rotating
biological contactor (RBC). A11 of the previous treatment schemes
involved suspended growth systems whereas the RBC is an adhered growth
treatment 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.
Table 6 summarizes the results obtained with the RBC study. The pH
of the effluent varied from 7.2 to 7.7 without any deficits in total
alkalinity. Regardless of the loading rates used (1.4 to 7.3 pounds COD
per 1,000 feet) 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 and at low loadings can produce effluents with
turbidities less than 27 JTU.
Anaerobic-Aerobic Series Treatment
Since 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. Thus,
anaerobic lagoons were examined.
Anaerobic lagoons by themselves would not be acceptable in many
instances because of the oxygen demand associated with the discharges
from anaerobic processes. Thus, all anaerobic lagoons were followed in
series with aerobic lagoons operated at a six-day detention period.
Another concern with the anaerobic process was that low temperatures
would cause depressed removal efficiencies. Thus, comparative studies
were conducted at 20 and 10 degrees C.
The data shown in Figure 12 is representative of the capability of
the combined system. A total hydraulic retention period of 26 days
reduced a total influent COD of 6,000 to 8,000 milligrams per liter to
between 5 and 15 milligrams per liter soluble BOD5. This system also
resulted in an effluent which contained large floes of rapidly settling
suspended solids leaving a clear effluent.
Data for all units are summarized in Table 7. All soluble COD
removal efficiencies exceeded 98 percent.
Similar graphical analysis for substrate removal coefficient, K,
was conducted for the anaerobic lagoons as for the aerobic lagoons. The
88
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oo
co
Table 6. ROTATING BIOLOGICAL CONTACTOR TREATMENT CHARACTERISTICS WHEN APPLIED TO
EGG BREAKING WASTES FROM PLANT B
(a,b
loading rates
Volumetric (gal/1,000 ft'/day) 40
Organic (Ib COD/1,000 ft'/day) 1.38
Parameter HRT, days
Influent characteristics
COD, total
TKN, total
Clarified effluent
characteristics
COD, total
COD, soluble
SS
PH
Alkalinity as CaC03
DO
TKN, total
NH3-N
N02-N
NO,-N
JTU
Observed sludge production,
mg solids produced in
clarified effluent per mg
COD removed
Removal efficiency, %
COD, total
COD, soluble
TKN, total
4,150
225
320
200
45
7.7
365
7.8
29.7
1.5
1.9
11.5
27
0.123
92.3
95.1
86.8
80
3.3
4,690
182
350
170
104
7.2
301
6.4
54.5
16.3
4,1
3.4
56
0.149
92.5
96.3
70.0
160
7.32
5,490
262
760
240
304
7.2
457
4.1
63.8
17.0
42.5
60
86
0.035
86.1
95.7
75.6
^Operating temperatures were 21 to 24 degrees C.
All units in rag/1 unless otherwise noted.
-------
10,000
5000
1000
500
o>
E
Q
O
O
O
z
m
O
O
03
100
50
10
O ANAEROBIC LAGOON, INFLUENT TOTAL COD
HRT= 20 DAYS , 20°C
A ANAEROBIC LAGOON,EFFLUENT TOTAL COD
A AEROBIC LAGOON, EFFLUENT TOTAL COD
NRT= 6 DAYS,20°C
• AEROBIC LAGOON, EFFLUENT SOLUBLE COD
• AEROBIC LAGOON, EFFLUENT SOLUBLE BOD5
I I I I I I I I I I I II
10 20 30 40 50 60
OPERATION TIME,days
70
Figure 12. 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.
90
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Table 7. CHARACTERISTICS OF THE ANAEROBIC-AEROBIC LAGOON SERIES
TREATMENT SYSTEM
Parameter
Temperature,
°C
HRT
Anaerobic unit
Aerobic unit
System effluent soluble COD,
mg/1
Removal efficient, total COD, %
Effluent turbidity, JTU
System number
1
20
20
6
90
98.7
4.8
2
10
20
6
66
98.4
9.1
3
20
10
6
72
98.5
-
4
10
10
6
86
98.1
21.4
5
20
5
6
72
96.7
-
91
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20 degree C anaerobic lagoon K was found to be 0.63 day'1. This was
very similar to the removal coefficients obtained for the aerobic lagoon
treatment of wastes (0.76 and 0.58 day1 for Plants A and B,
respectively). This procedure was not applicable to the lower
temperature units because the effluent characteristics of the units
studied were similar. However, the observed efficiencies at 10 and 20-
day hydraulic retention periods at 10 degrees C were similar to that
observed at 20 degrees C. Thus, it can be concluded that there was
little effect on the substrate removal coefficient between 10 and 20
degrees C. The greatest difference occurred in the loss of
nitrification activity at 10 degrees C.
Perhaps the most impressive characteristics of the combination
anaerobic-aerobic lagoon system was the high clarity and highly
flocculated 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 and 10 degrees C. Since all solids settled
rapidly, the soluble BODs values shown in Figure 12 of about 10
milligrams per liter are indicative of the efficiency that this
treatment combination is capable of achieving with an influenct COD
varying between 5,000 and 10,000 milligrams per liter and a total system
hydraulic detention period of 26 days.
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 enables the use of smaller systems to achieve the same treatment
efficiency. Data supporting this statement are illustrated in Figure
13. 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. Thus, this data indicates that
addition of individual compartments to 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.
Lagoon Sludge Accumulation
Although design of the sludge handling facilities was beyond the
scope of this study, empirical approximations of the quantities of
sludge accumulated in both the anaerobic and the aerobic lagoons would
assist in determining the feasibility of this system. The data for
measured sludge accumulation in these systems are summarized in Tables 8
92
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100
90
80
- 70
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o
2
UJ
o 60
iZ
u_
<
>
O
ac
50
40
o
o
O 30
20 —
10
AEROBIC
(5 CELL)
ANAEROBIC(5CELL)
• TOTAL COO
1
1
AERATED
(I CELL)
ANAEROBIC
(I CELL)
1
10 20 30
HYDRAULIC RETENTION PERIOD,days
Figure 13. Comparison of multi-cell and single cell aerobic and
anaerobic treatment processes at 20°C.
93
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and 9. The quantity of solids accumulation was expressed as a fraction
of the solids added for the anaerobic lagoon, and as a percent of the
total flow volume treated for the aerobic lagoons. In all anaerobic
units operated at 20 degrees C, the accumulation of solids was low and
represented about 5 percent of the solids added. The higher
accumulations at 10 degrees C reflects lower rates of stabilization.
However, bioprecipitation of the solids in these units enable the
treatment efficiency at the lower temperatures to be nearly equal to
that at 20 degrees C.
DISCUSSION
Egg Breaking Waste Generation and In-^Plant Controls
The average facility that did not practice in-plant waste control
was found to lose 12.5 percent of its processed product to the sewer.
This level of product loss agrees with a recent survey of plant
practices in the United States where average loss was reported to be
12.1 percent with the maximum range of 4 to 25 percent. "* Several
facilities with losses less than 4 percent were reported but discarded
in the survey. "* In the instances with the New York facilities, it was
found to be relatively simple and inexpensive to reduce the loss from 12
percent down to 6 percent, and in one case down to 3 percent on a long-
term basis. On the basis of this analysis, it was concluded that of the
total losses of around 12 percent, about half are readily controlled by
good in-plant management. Of the remaining wastes (6 percent), 3
percent can be removed by careful management and further implementation
of some of the more costly suggestions shown in Table 4. This level of
in-plant control would provide 75 percent 800$ reduction and would be
considered difficult to achieve by many facilities on a long-term basis.
It is estimated that product losses in the industry could be controlled
at about 2 percent with high quality management using all
recommendations given in Table 4.
The maximum range of water and product loss for all plants was 0.43
to 1.41 gallons per dozen and 0.0048 to 0.0478 pounds BOD* per dozen
eggs processed (0.0062 to 0.058 pounds BOD5 per pound liquid egg
produced), respectively. On the average, more than one egg per dozen
processed goes to ths sewer in 0.9 gallons of water. The water use
compares well with the United States survey4 where the range was 0.485
to 3.27 gallons per dozen eggs processed with an average of 1.49 gallons
per dozen eggs. A survey of three Dutch plants reported water use to be
0.49 to 1.56 gallons per dozen eggs.8 But the Dutch study reported the
amount of product loss varying from 0.5 to 4.2 percent.
94
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Table 8. MEASURED SLUDGE SOLIDS ACCUMULATION RATE IN ANAEROBIC LAGOONS
Anaerobic lagoon operating conditions
HRT, days
10
20
5
10
20
Temperature, °C
10
10
20
20
20
Solids accumulation rate
% of total solids added per day
30
68
12
6.0
5.4
Table 9. MEASURED SLUDGE VOLUME ACCUMULATION RATE IN EFFLUENTS FROM
6-DAY HRT AEROBIC LAGOONS FOLLOWING ANAEROBIC LAGOONS
Pretreatment
anaerobic lagoons
HRT, days
10
20
20
10 (5-cell)
Temperature, °C
10
10
20
20
Aerobic lagoon
temperature,
°C
10
10
20
20
Sludge volume
accumulated,
% total volume treated
1.7
3.7
2.7
1.2
95
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In large plants (10 to 12 breakers), it may be uneconomical to
collect and land dispose 9,460 to 13,625 liters (2,500 to 3,600 gallons)
a day of the highly contaminated egg washing waters. An alternative
solution might be to try to recover the protein either by drying,
chemical precipitation, or heat treatment.
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.9 have shown that commercially processed
whole eggs contain simiT?r~Ea"cterial population counts. The same study
concluded that product contamination is instead highly dependent upon
sanitation practices during clean-up operations.
Results of bacteriological studies conducted in this study show
that bacteria counts in egg washing liquids increase enormously over the
four-hour run periods. In fact, the data suggests that in some cases
egg washing appears to contaminate egg surfaces rather than clean them.
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 0.04 pounds COD per dozen eggs of which 25 percent
results from washers and 5.83 x 108 dozen eggs are broken annually, it
is estimated that 12 million pounds of inedible liquid egg could be
recovered by eliminating washers. Further study needs to be conducted
on this possible change in processing.
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. Air drying collects and retains
the nutrients present in the adhering liquid portion of the shell,10 and
may be an asset when sold to poultry feed producers.11 Assuming 20
million cases of egg at 47 pounds per case are processed each year, 11
percent of an egg's weight is shell, the egg breaking industry has
capabilities of providing nearly 53,000 tons of dried egg shells
products annually.
Although egg breaking accounts for only 11 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.
BOD5 losses from the grading operation of Plant C amount to 0.001 pounds
BOD5 per dozen eggs graded. Hamm ejt al.12 indicated that egg grading
losses average 0.0014 pounds BOD5 per~3ozen occur in egg grading plants.
Therefore, egg breakers handle a small portion of the country's eggs,
96
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but the losses per dozen are tenfold higher than losses of grading
operations.
Treatability of Egg Breaking Facility Wastewaters
This treatability study encompassed a variety of aerobic and
combination 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 demand substances. These
results are illustrated in Figure 14. Thus, the treatment system which
was found to be most effective in controlling the egg breaking
wastewater is shown in Figure 15.
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.
Another possible drawback of these systems is the possible impact
of low temperatures on treatment plant efficiency. At temperatures
lower than 10 degrees C, the removal capacity of this combination may be
diminished even though the organic removal efficiencies were nearly the
same at 10 degrees C as they were at 20 degrees 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"1 versus 0.67 day'1,
respectively), and also because there appeared to be no significant
effect in effluent total COD quality when the temperature was decreased
from 20 to 10 degrees C.
Oftentimes municipal systems utilize aerobic treatment processes.
If an industry such as an egg breaking plant discharges 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, municipal aerobic plant upsets may 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
97
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AEROBIC
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PROCESS
(HRT DAYS-TEMP °C)
ANAEROBIC-AEROBIC
LAGOON
Figure 14. Summary of effluent turbidity from various aerobic and
anaerobic-aerobic treatment systems.
-------
ANAEROBIC LAGOON
(20 DAY HRT)
INFLUENT
CO
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AEROBIC LAGOON
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Figure 15. A recommended wastewater treatment system to achieve maximum
organic pollution control of egg breaking wastewaters.
-------
wastes constitute less than 10 percent of the municipality's organic
loading.
CONCLUSIONS
1. Eleven percent of eggs produced in the United States go to egg
breaking plants, resulting in 2.9 x 108 kilograms (6.40 x 10*
pounds) of liquid egg products which grossed $195 million in 1969.
2. 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 1,500 percent of the wastes
generated from all other sources in the communities in which they
were located.
3. Wastewater characterization indicated a highly contaminated
discharge with COD's greater than 6,000 milligrams per liter, and
BODS equal to about 60 percent 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 efficient
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 three 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 loss in all five plants sampled was 12.5 percent (by
weight) of the processed output.
5. The measured average amount of liquid egg recovered per dozen eggs
broken was 0.55 kilograms (1.21 pounds) and this represented
recovery of 80 percent of the total egg weight.
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 kilograms BOD5 per kilogram egg liquid
produced and wastewater volumes of 7.5 liters per kilogram (0.90
gallons per pound) egg liquid produced. In-plant modifications
100
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decreased average BOD5 losses by 50 percent and decreased
wastewater volume by 24 percent.
8. 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.
9. 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.
10. On a national basis, in-plant waste control would result in annual
product recovery of 3.2 x 107 kilograms (7 x 107 pounds) of liquid
egg of a quality suitable for animal food which is now lost to the
sewer.
11. Egg breaking wastes as obtained from three facilities, A, B and C,
were highly biodegradable with no observed toxic effect to
biological treatment processes.
12. 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.
13. Aerobic lagoons, with hydraulic retention times of 30 days reduced
the total COD from 5,800 milligrams per liter to 1,000 milligrams
per liter, and resulted in a high effluent turbidity.
14. When an anaerobic lagoon was followed by a six day HRT aerobic
lagoon, the overall COD removal efficiency was greater than 98
percent, at 20 degrees C and 10 degrees 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 degrees C with a 20 day
HRT anaerobic primary unit averaged as follows: 90 milligrams per
liter soluble COD, 13 milligrams per liter soluble BOD5, 92
milligrams per liter N03-N, 21 milligrams per liter NH3-N and
turbidity of 5 JTU.
101
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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.
ACKNOWLEDGEMENTS
Thus study is the result of a multidisciplinary effort representing
four major disciplines. The authors are appreciative of the advice,
contributions and support of the following individuals: C. J. Barton,
D. Brown, R. J. Cunngingham, E. David, R. Draper, R. Oil, P. Gellert, G.
Grey, R. J. Hynek, C. R. Kilmer, P. Kodukula, M. Kool, R. McCrea, J. H.
Martin, R. McNamara, J. N. Nickum, R. Ridley, S. Sotiracopoulos, and W.
T. Wallace.
Support of this study was provided by the College of Agriculture
and Life Sciences of Cornell University and the United States
Environmental Protection Agency, Grant S802174.
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REFERENCES
1. Jewell, W. J., H. R. David, 0. F. Johndrew, Jr., R. C. Loehr, W.
Slderewlcz, and R. R. Zall. Egg Breaking and Processing Waste
Control and Treatment. US Environmental Protection Agency Report.
To be published. 1975.
2. Jasper, A. W. Selected Poultry Industry Statistics. American Farm
Bureau Federation. May 1974.
3. Faber, F. L. The Egg Products Industry: Structure, Practices and
Costs, 1951-69. US Department of Agriculture, Washington.
Marketing Research Report No. 917. February 1971.
4. Kaufman, V. F., D. H. Bergquist, K. Ijicki, and A. L. Porter.
Wastewater Control at Egg Products Plants. An Informal Report from
the Poultry and Egg Institute of America and the US Department of
Agriculture, Washington. 1974. 11 p.
5. American Public Health Association Standard Methods for the
Examination of Water and Waste Water. New York. 1971. 874 p.
6. Prakasan, T. B. S., E. 6. 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 Agricultural Engineers
Committee SE-42, Chicago. 1972.
7. Jeris, J. S. A Rapid COD Test. Water and Waste Engineering.
4:89. 1967.
8. Dekleine, H. and G. P. Friskorn. Research into the Wastewater
Disposal Situation in Egg-Breaking Industries. Inst. for Poultry
Research. State Agriculture Waste Disposal Service Report No.
4372. Holland. September 1972. 32 p.
9. Kraft, A. A., 6. 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.
10. Walton, H. V., 0. J. Cotterill, and J. M. Vandepopuliere. Cashing
in on Breaking Plant Wastes. Egg Industry. 6:25-26. April 1973.
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11. 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, Chicago, December 11-15, 1972. Paper No. 72-886.
12. 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.
BIBLIOGRAPHY
Jones, H. B. and H. R. Smalley. Vertically Integrated Methods of
Producing and Marketing Eggs: An Economic Evaluation. Georgia
Agricultural Experiment Station, Athens. Bulletin N.S. 160. May
1966.
«r
Kondele, J. W. and E. C. Heinsohn. The Egg Products Industry of the US,
Part 2, Economic and Technological Trends, 1938-61. Agricultural
Experiment Station, Kansas State University. North Central
Regional Research Publication No. 154. Bulletin 466. January
1964.
Statistical Research Service. Egg Products, February 1968 - April 1971.
US Department of Agriculture, Washington.
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PULP RECOVERY FROM TOMATO PEEL RESIDUE
W. G. Schultz*
R. P. Graham*
M. R. Hart*
SUMMARY
Caustic peeling of tomatoes results in the loss of food material
and creates waste material. By altering the peeling process and
subsequent operations, it is possible to increase the amount of
recovered food material and simultaneously reduce the quantity of
organic wastes which are normally discharged. A similar situation
exists with the tomato juicing operation where there is a food-grade
material discharged with the pomace residue that results from the
extraction-finishing operations. Collectively, the peel and pomace
residues that go to waste disposal in California amount to about 400,000
tons per year. About half of this tomato residue can be recovered as
food-grade material.
This paper describes proposed development and evaluation of a
marketable product. Mechanical removal with rubber discs of the skin
from caustically peeled tomatoes will reduce water usage so that the
peel can be separated into concentrated pulp and skin fractions. The
alkaline pulp fraction can be neutralized in a variety of ways, either
directly with acid, or by combining with acid-treated macerate. The
resulting puree-pulp can then be merged with tomato pulp from other
regular plant operations and used as a puree-pulp, hot sauce, catsup,
etc. By appropriate processing, a food-grade product can be produced
from what otherwise would be lost as a waste.
*Western Regional Research Center, Agricultural Research Service, US
Department of Agriculture, Berkeley, California 94710.
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INTRODUCTION
Casutic Peeling
A peeling operation to remove skin materials is a necessary step in
the processing of numerous fruits and vegetables before preservation by
freezing or canning. Volume wise, caustic peeling is the most
prevalent. It is commonly done on peaches, tomatoes, and potatoes by
exposing the produce to a caustic solution and then following this by a
wash using large volumes of water to remove the softened outer skin and
residual caustic. This washing not only removes the outer skin but also
some of the underlying edible flesh. Where operations are conducted by
this conventional caustic peeling, the liquid effluent is frequently a
primary source of pollution in the plant's total waste flow.
The development at the Western Regional Research Center (WRRC),
Berkeley, California, of an infra-red, or "dry caustic", peeling process
for white potatoes has contributed to a significant reduction of the
quantity of waste water pollutants generated during the peeling of
potatoes.1 Through this process, which has been widely adopted by the
potato processing industry, potato peel can now be recovered and
converted to cattle feed, thereby creating a by-product from what was
previously a waste material.2
The technology has been successfully modified and applied to a
variety of other caustic-peeled commodities, such as peaches. However,
the utility of recovered peel material varies widely. Where by-products
are of limited value, the costs for process modification and operations
are often prohibitive. Where no present use for the by-product exists,
the recovered material must be discarded, usually to a sanitary landfill
or other land-disposal site.
Peel material, whether potato or tomato, is difficult to handle
because the reduction in wash water leaves a peel residue with a pH 11
to 12 and a high sodium content. High pH material is abnormal to waste
treatment plants, and it may require a neutralizing pretreatment with
acid if sufficient dilution is not available. The high sodium content
is not desirable in the California Valley areas which may already be
borderline for crop sodium tolerance. An example is the San Luis drain
canal from the lower San Joaquin Valley, which brings high-mineral field
drainage about 150 miles from the lower valley to where the seawater
reaches inland. From the environmental view, solid peel-waste disposal
may merely be transferring the liquid-disposal problem to an
intermediate solids-disposal problem if there is eventual runoff from
the disposal site. The solution is to reduce peel waste at the point of
origin.
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Tomato Processing
Caustic or lye peeling of tomatoes involves submerging the fruit
for about 30 seconds in a 16 percent sodium hydroxide bath at about 200
degrees F. A significant quantity of edible tissue is removed along
with the peel. The total resulting residue is significant in terms of
quantity, reduced recovery, and cost. For example, during 1974 about
6.3 million tons of tomatoes were harvested for processing in
California; this was 80 percent of the total United States processing-
tomato harvest. Of this 6.3 million tons in California, about 90
percent, or 5.7 million tons, were processed by plants located in the
Sacramento and San Joaquin river basins, which drain into San Francisco
Bay. Of this California tonnage, an estimated 15 percent, or 850,000
tons, was peeled, primarily by conventional, water-intensive methods;
this resulted in a 20 percent weight loss, or a total of 170,000 tons of
tomato material (6 percent solids on a wet basis). This may also be
regarded as the generation of an equivalent weight of organic pollutants
which must be removed from the water through subsequent treatment prior
to the discharge of these processing waste waters to receiving streams.
These same problems exist, albeit to a lesser extent, in other parts of
the country, e.g., Ohio, Indiana, New Jersey, where tomatoes are
processed.
The Food and Drug Administration (FDA) Standards of Identity under
21 CFR 53.10, 53.20, and 53.30 for tomato pulp/puree allow this material
to be from one of three sources. One source is the liquid obtained from
the residue from preparing such tomatoes for canning, consisting of
peelings and cores, with or without such tomatoes or pieces thereof.
This, then, is a consideration for the utilization of pulp recovered
from the peeling of tomatoes destined for whole pack; about 15 percent
of the commercial tomato pack is whole tomatoes. The remaining 85
percent (5.4 million tons) of California processing tomatoes is
processed into tomato juice, puree (pulp), paste, and sauce. The juices
used to produce these products are obtained by macerating whole
tomatoes, heating, and extracting the pulp and juices with "finishers".
A finisher is a screen (sieve) device having mechanical paddles to move
the material through the screen. The residue remaining after juice
extraction consists primarily of seeds, skin, and fiber, and is
collectively referred to as pomace. The utility of pomace in by-
products is presently very limited. The bulk of the 200,000 tons (33
percent solids) generated during 1974 was disposed of on land. The
balance was dehydrated for use as feed for animals (e.g., fur-bearing)
whose parts or products are not destined for human consumption.
Feed use of pomace or peel waste is limited primarily by the
presence of insecticide residues in concentrations greater than that now
permitted for feed. Currently, the insecticide toxaphene is used on
growing tomatoes. This is an oil-soluble material and it tends to be
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located in the waxy layer of the tomato skin. Since the seeds in the
pomace contain about 20 percent protein, skin removal could increase the
utility of pomace for feed. The pomace discharged from finishers
contains unrecovered tomato pulp similar in quality to the juice passing
through the finisher screen. Recovery of the pulp, which adheres to the
tomato skin, will not only increase the raw product yield, but may
facilitate separation of the skin from the residual seeds and fiber
materials.
There are, therefore, two promising areas for recovering additional
pulp from tomato residue which is now commonly discarded as waste. One
is the pulp in the peeling residue from the caustic peeling of tomatoes
destined for a whole-tomato pack; the other is the pulp in the pomace
from tomato macerate destined for juice, puree, paste, catsup, and such
products going through a finisher. In both cases, the potential of both
physical and economical recovery of these pulps is promising, based on
laboratory and pilot studies. Successful recovery on a commercial scale
will significantly increase production yields while reducing
substantially the quantity of pomace which must be discarded. Reduction
in residue volume will alleviate environmental problems (vectors, odors,
and runoff) associated with land disposal of such wastes. At 200,000 to
250,000 tons per year of pomace residue, and 170,000 tons per year of
peeling residue in California alone, there are collectively about
400,000 tons per year of residue available to consider. If half of this
400,000 tons per year is considered recoverable as food-grade material,
there are 200,000 tons per year to be considered either as a waste
disposal expense or as a usable food. As a waste disposal expense,
there is an estimated annual $1 million disposal expense at $5 per ton
for caustic material sent to a sanitary landfill. If the 200,000 tons
per year is viewed as a food material, the potential value is $12
million, based on a raw tomato value of $60 per ton at the cannery.
This is an attractive spread between waste disposal expense and value as
a product.
RECOVERY METHODS
Past Tests
Utilization of peel residue was considered during pilot tests in
1973.* Peel residue recovered from rubber disc peelers was similar to
macerated tomatoes except for its high alkalinity and skin content, and
the absence of seeds and core fiber. The peel material, which is
removed without additional use of water except for a minimal rinse at
most, can be readily segregated and separately handled. This peel
material consists primarily of skin and tomato pulp in a ratio of about
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1:3, respectively, on a dry-wieght basis, and contains about 0.7 percent
sodium hydroxide (wet basis), resulting in a pH 11 to 12, The pulp
fraction can be of food quality since most of the cells are intact, and
this layer of pulp contains a relatively high concentration of pigment
with respect to the whole tomato. Therefore, the pulp represents a
significant quantity of recoverable and utilizable material, potentially
valuable for food use. In a large scale test conducted in 1974, 124
cases of puree were prepared in commerical equipment.5 Caustic peel
residue containing about 8 percent total solids (TS) was separated into
skin and pulp fractions, the skin fraction was discarded, and the
caustic pulp fraction was processed further by first neutralizing with
food-grade hydrochloric acid. Then, a final puree product was made by
mixing the neutralized pulp with conventionally processed pulp and
concentrating this misture to 10.5 percent TS. It was tentatively
concluded that the product was promising as to color, taste, salt
content (from neutralization of the caustic), and the low pesticide
residue. Wetting agent content in the product was not determined.
Wetting agents are normally used in caustic peeling baths to effect a
faster and more uniform action in loosening the peel. There are FDA
tolerances on their use, and a marketable product would need to take
this into consideration.
Peel Pulp Residue Recovery Methods
To process caustic peel residue into a marketable food product,
consideration must be given to separating out the skin if pesticide
residues are on the skin, and if product grades are affected by skin
fragments. A first step is to separate the caustic peel residue into
pulp and skin fractions with a finisher. The pulp passes through the
finisher screen and goes on to further processing into food. The skin
does not pass through the screen, and is discharged from the finisher as
a solid material; this "waste" skin can be combined with other cannery
solid waste that is destined for disposal, presumably to a sanitary
landfill.
The pH 11 to 12 tomato pulp coming through the finisher screen is
quite caustic; there are, however, several ways in which this pulp can
be neutralized and eventually incorporated into the main food material
stream of the cannery. One is to neutralize the alkaline pulp directly
with food-grade hydrochloric acid to the normal pH of processed tomatoes
which is about pH 4.3; the new result of this neutralization is the
formation of sodium chloride (table salt). This use of acid and the
resulting presence of additional salt in tomato materials, is allowed
under the FDA Standards of Identity, 21 CFR 53.10, 53.20, and 53.30.
Rather than adding acid per se to the peel residue, alternatives can be
considered, such as adding previously acidified tomato macerate or
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pomace. These and other alternatives will now be considered in the
following subcategories.
Macerate Treatment—General Description. Several acid treatment
processes for tomatoes have been successfully demonstrated by WRRC, and
one has received FDA approval. One is called an "acid break"; this
utilizes a low pH of about 1.5 to inactivate/inhibit enzyme action, and
loosen the pulp cells for increased extraction of pulp beyond that
possible through only a hot break. The second, termed "acid treatment",
and approved by FDA, involved acidification to pH 2.7 to loosen the pulp
cells for increased extraction.6*7 The third is an adjustment to pH 6
to thicken or increase the consistency (viscosity) of the pulp; this is
a useful attribute in sauces and purees.
Macerate Acidic Treatment—The Acid Break, pH 1.5. If the pH of a
tomatomacerate(crushed,whole tomatoes including skin and seeds) is
reduced to about 1.5, two things can be accomplished. First, the normal
tomato enzyme is inhibited. These enzymes, if not inactivated in a
matter of seconds by means of heat or low pH, will break down the normal
tomato consistency that is necessary in most tomato products such as
catsup, puree, and sauces. Second, the residual tomato pulp that
normally adheres to the pomace after a commercial hot break and
finishing is loosened sufficiently so that it will remain with the
"juice" during the finishing operation. The result is that additional
food-quality tomato solids are recovered to the extent that the finisher
pomace solids are reduced by about half. The pomace waste that does
remain for disposal or utilization contains about 50 percent total
solids. There is, therefore, less tonnage for disposal or, if the
material is dehydrated for animal feed, significantly less fuel is
required. For example, the energy needed to dry 50 percent moisture
material is about 25 percent less than that needed for 63 percent
moisture materials. The extracted low pH material may be stabilized by
heating to permanently inactivate the pectinolytic enzymes before, or
simultaneously with neutralization of the added acid. It can be
neutralized with the alkaline peel residue to the mutual benefit of both
materials without adding extraneous neutralizing material.
Macerate Acidic Treatment—The Acid Treatment, pH 2.7. Acid treatment
of pH 2.7 does not inhibit enzyme action ana*these enzymes must be
adequately inactivated by a hot break as in present day processing. An
acid treatment of hot-tomato macerate at pH 2.7 will loosen the pulp
cells for increased extraction of pulp beyond that possible by a hot
break. Treatment of pH 2.7 loosens and facilitates the removal of
residual pulp from the seeds, fiber, and skin to increase pulp recovery
and, thereby, reduce pomace waste by about 40 percent. A product with
greater consistency (viscosity) than normal can be obtained, but is
time-temperature labile. Under current processing practice, where the
aggregate time at temperatures about 160 degrees F is less than one
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hour, a consistency increase can be expected. Beyond two hours,
probably no consistency increase will result. This acid-treated pulp
can be merged with the alkaline peel residue to restore the normal pH of
this mixture to a natural tomato pH of 4.3. On neutralization of pH 2.7
material, sodium chloride is formed; this added sodium chloride amounts
to about 0.4 percent. A pH 2.7 material at 70 degrees F is stable for a
few hours, which allows a non-neutralized macerate or juice to be
transported from a field-juicing site to a central cannery for finish
processing. Therefore, the geographic origin of the peel residue and
acidified .macerate do not have to be the same; they could originate 100
to 200 miles apart. A so-called field, rural, or decentralized tomato
preparation and juicing station has the potential advantage of disposing
of the wastes from cleaning and pomacing operations back onto a tomato
field in the immediate vicinity. The option for partial processing at a
decentralized location also moves jobs back to the farm areas, and
reduces the transportation damage resulting from hauling raw tomatoes
over long distances. Studies have shown that this transit loss can
amount to 10 percent or more.
Macerate Alkalinization Treatment—The Alkaline Treatment, pH 6. A pH
(> treatment 6? macerate gives results somewhat similar to a pH 2.7
treatment, i.e., increased consistency and decreased pomace, due to the
removal of more pulp from the seeds and fiber than results from only a
hot break. The mechanism and process condition have not yet been
sufficiently worked out. Possible the pH 6 treatment gives a higher
consistency but a lesser recovery from the pomace.
Pomace Residue Treatment—Acid and Alkaline, pH 2.7 and pH 6. Pulp
adhering to tomato pomace can Be recovered By either of two pH
adjustments: (1) adjusting and holding at about pH 6, or (2) acidifying
and holding the pomace at pH 2.7. The acidification approach loosens
the tomato pulp cells which adhere to the skin beyond the loosening
accomplished by even a prolonged hot-breat. The hot-break, heating to
212 degrees F, inactivates enzymes and also loosens the pulp; this
facilitates subsequent pulp extraction from the seeds and fiber in the
finisher. A prolonged hot break degrades both color and flavor. As
with the pH-treated peel residue, this recovered tomato pulp may be
brought back to the natural pH of tomatoes, either by a direct addition
of food-grade acid to the pH 6 material, or by adding caustic to the pH
2.7 material; or two streams of "opposite" pH material can be merged, as
next described. As another alternative, the pH can be adjusted with the
alkaline peel residue.
ill
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PROPOSED PLANS
While various methods have been discussed for utilizing the peel
residue, pomace, and macerate materials, there are undetermined and
unresolved process aspects on yield, rates, time span, recovery, and
operating points. This means that it is too early for a commercial
installation. On product quality and marketability, questions exist on
pesticide residues, wetting agents, microbiology, salt content, color,
flavor, consistency, and nutrients. Therefore, further experiments are
proposed to provide this information on commercial equipment at full-
flow rates. It has been proposed that this work be done as a
cooperative effort by several agencies. These organization are: (1) US
Department of Agriculture (USDA), Agricultural Research Service, Western
Regional Research Laboratory, Berkeley, California, (2) National Canners
Association (NCA), Western Laboratory, Berkeley, California, (3)
commercial tomato canneries. The particular cannery site(s) are unknown
at this time, and the local cannery situation will make considerable
difference as to what is experimentally practical. The processing
season is mid-July through mid-October. The laboratory and process
analysis will take place throughout the year.
Process Considerations
Typical cannery operations process 80 to 180 tons per hour of
tomatoes with 20 to 40 tons per hour undergoing a caustic peeling
operation over two to four parallel lines, resulting in 4 to 8 tons per
hour of caustic peel residue. The proposed experimental trials will be
through a single line using typical commercial equipment, at full flow,
but for a short duration so as not to consume undue amounts of materials
and time. Packs on the order of 1,000 pounds each will be processed.
Full-flow rates are considered important becuase results from reduced -
flows can be markedly different. Trials will be with controlled
temperature, pH, flow rate, residence time, weighed wastes and similar
conditions and data that are needed to calculate recovery, make a
material balance, and select optimum process parameters. When
practicable, the BOD, COD, or TOC will be measured on various waste
streams from the conventional (control) and alternate operations.
Sanitation considerations are necessary because of the potential
microbiological build-up between the peeler and the heating and pH
adjustment vessel (Figure 1).
Currently, two commercial types of mechanical disc peel removers
are in use on tomatoes. One is a reely type with the disc rotation
across or 90 degrees to the reel axis and tomato flow (Magnuson
Engineers, Inc., San Jose, California). The others are flat-bed types
with the disc rotation parallel with the tomato flow (FMC Corporation,
San Jose, California; Melrose Metal Products, Co., Oakland, California;
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1. CONTROL-—conventionally processed tomato macerate and pulp.
2. NEUTRALIZATION OF PEEL PULP BY ACID—peel pulp directly
neutralized with acid to pH 4.2 ± 0.2.
3. NEUTRALIZATION OF PEEL PULP BY ACIDIFIED MACERATE—peel pulp
adjusted to pH 4.2 ± 0.2 with acid treated pH 2.7 conventional
pulp, macerate, or pomace.
4. ALKALINIZATION OF CONVENTIONAL PULP BY CAUSTIC PEEL PULP—
conventional pulp is adjusted to pH 6 with caustic peel pulp.
Mixture is then adjusted to pH 4.2 ± 0.2 with acid.
Figure 1. Process options for caustic peel pulp.
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and South Valley Manufacturing, Inc., Gilroy, California). Some use
water sprays in the peel removal section and some do not. If the peel
pulp is to be recovered, the advantage is with the equipment that does
not dilute the peel with water and, therefore, gives a "dry" peel with
about 8 percent TS. High solids content is desirable for processing as
well as effluent disposal. Typically, a flow of 2 tons per hour of peel
residue is expected to be available from one peeler, though the actual
rate will depend on the particular equipment, operation, and cannery at
which the trials are conducted.
Process and flow options for the control, neutralization, and
alkalinization procedures are shown in Figures 1 and 2. The primary
investigation is to be on the direct neutralization of pH 11 to 12 peel
pulp by acid (Option 2); this is to be compared with the "Control" of
conventionally processed tomato macerate and pulp (Option 1). Option 3,
Neutralization of Peel Pulp by Acifified Macerate, is a means of putting
the acid to a dual use by first using it to give an acid treatment to
otherwise conventionally processed macerate for increased yeild as
previously described under "Macerate Acidic Treatment—The Acid
Treatment, pH 2.7"; then the acidified macerate is mixed with the peel
pulp to mutually neutralize both streams to pH 4.2 ± 0.2. This Option 3
is considered an economy of acid use because it is first used to
increase the yield obtained from conventionally processed macerate
before using it as a neturalizing agent. Since the increased yield
through acid treatment has previously been established,6'7 Option 3 is a
secondary consideration. The "Alkalinization of Conventional Pulp by
Caustic Peel Pulp" (Option 4), is of lesser interest than the above
measures because there is not sufficient laboratory-scale information
available at present to fully define the mechanism and conditions under
which pulp yield and consistency are increased. These lesser options
will be reduced or expanded, depending on results and available
resources. Initially, direct neutralization of the caustic peel pulp by
food-grade hydrochloric acid is considered the most practical under
commercial processing conditions, and the basic, initial effort will
concentrate on this.
Peel pulp is to be merged with conventional or acid-treated pulp in
ratios of 1:3 or as much as 1:20, depending on what relative volumes are
normal to a cannery's operations. This mixture will then be vacuum
evaporated to 8 to 24 percent soluble solids to conform to the needs of
tomato puree-pulp or hot sauce. Preliminary results in 1974 indicated
that product quality was better in a 1:3 ratio than a 1:0.5
Product Considerations
The result of processing the caustic peel residue is considered to
be a marketable product containing salt, and used in formulating tomato
114
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01
Peel Residue at pH 11-12
from Caustic Peeler
Clean, Whole
Tomatoes
Pomace from
Other Operations
Waste
Skin
> r
Steam —
<—
eO '~J xv;
_— ' X^-1
^^
/^->
/v /^-' —
. J — t-irtvt i _r.__ -,-_ ^ VflPI M Iffl
—-^w. I^\/a ttrt v*3 4* f
»r
* — Acid
«— Base
F
ni JiL'< 1
i er )
^ Heating ar
pH Adjustn
Vessel!
pH Control
Sterilizer
Figure 2. Flow diagram.
-------
puree, catsup, pizza sauce, or other concentrated tomato products.
Initially, an 8 percent soluble solids (SS) puree will be made, though
the experimental range is considered to be that of a tomato puree-pulp
which contains 8 to 24 percent SS and conforms to the USDA Quality Grade
Standard 50-5081 for puree-pulp. The salt levels resulting from the
neutralization of the sodium hydroxide in the peel pulp blended with
conventional pulp are compatible with such products as salted puree-
pulp, hot sauce, pizza sauce, catsup, etc. Hot sauce is a more
universally marketed product that salter puree-pulp; as a market item,
it might be the more attractive end product. Salter puree-pulp would
seem to conform to the FDA Standard of Identity 21 CFR 53.20, though
presumably an actual ruling on the process, ingredients, and labeling is
the preferred method by which to introduce a new process and product.
Samples are to be collected by both NCA and WRRC in order to
determine overall product quality, salt, solids, consistency, color,
nutrients, and residues of pesticides, wetting agent, etc. Since
toxaphene is commonly used to spray tomato fields, and it tends to
remain in the waxy layer of the skin, the quality of the separation of
peel skin from the peel pulp is crucial. A direct analysis of the
product is to be made for toxaphene and other insecticides.
A somewhat similar need exists to know whether or not if wetting
agents are carried over into the product. It is current, general
commercial practice to add a wetting agent to the caustic peeling bath
to aid peeling speed and uniformity. At present, it is not known how
stable the wetting agents are during the peeling operation, and whether
their effective disappearance during the peeling operation is due to:
(a) decomposition, (b) entrainment with the tomatoes, or (c) some other
cause. Typical compounds approved by FDA (21 CFR 121.1091), for use as
wetting agents in peeling baths and in current use are: heptanoic acid,
sodium 2-ethylhexyl sulfate, sodium n-alkylbenzene sulfonate, etc. At
this time it appears that an analytical method to directly measure the
wetting agent, if any, in the final product may need to be developed.
CONCLUSIONS
In conclusion, these proposed tests will determine the feasibility
of recovering food-grade tomato pulp from caustic peeling residue. This
pulp is to be used in a marketable, salted product such as a puree-pulp,
hot sauce, pizza sauce, catsup, or other concentrated tomato product.
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REFERENCES
1. Graham, R. P., C. C. Huxsoll, M. L. Weaver, and A. I. Morgan, Jr.
Dry Caustic Peeling of Potatoes. Food Techno!. 23:61. 1969.
2. Gee, M., C. C. Huxsol!, and R. P. Graham. Acidification of Dry
Caustic Peeling Waste by Lactic Acid Fermentation. Am. Potato J.
51:126. 1974.
3. Hart, M. R., R. P. Graham, C. C. Huxsoll, and G. S. Williams. An
Experimental Dry Caustic Peeler for Cling Peaches and Other Fruits.
J. Food Sci. 35:839. 1970.
4. Hart, M. R., R. P. Graham, G. S. Williams, and P. R. Hanni. Lye
Peeling of Tomatoes Using Rotating Rubber Discs. Food Techno!.
28:38. 1974.
5. Ostertag, B. and K. Robe. Waterless Pee! Removal. Food Proc.
36:60. 1975.
6. Schultz, W. G., R. P. Graham, W. C. Rockwell, J. L. Bomben, J. C.
Miers, and J. R. Wagner. Field Processing of Tomatoes, Part I,
Process and Design. J. Food Sci. 36:397. 1971.
7. Miers, J. C., J. R. Wagner, M. D. Nutting, W. G. Schultz, R.
Becker, H. J. Neumann, W. C. Dietrich, and D. W. Sanshuck. Field
Processing of Tomatoes, Part II, Product Quality and Composition.
0. Food Sci. 36:400. 1971.
117
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PROTEIN PRODUCTION FROM CHEESE WHEY
FERMENTATION*
Chu H. Tzeng**
Douglas Sisson**
Sheldon Bernstein**
INTRODUCTION
The magnitude of the whey disposal problem in the United States has
been documented elsewhere.1 Suffice to say, while great strides have
been made in its utilization and recovery, whey still represents a
tremendous source of potential pollution. Raw whey, as it is drained
from the cheese vats, has a BOD5 of 30,000 to 50,000 parts per million
and should be recovered and utilized in some manner to avoid the very
great cost of pollution abatement. It may be condensed, dried,
fractionated or deminerali zed—all processes which produce products
taking advantage to varying degrees of the protein, lactose and minerals
present. The huge volume of raw material, however, often causes
problems due to the large capital investment necessary for sophisticated
equipment and a limited specialized market. It is not unusual for a
single cheese factory to produce 1 million pounds or more of liquid whey
a day, a source that cannot be turned on or off at will, and the total
amount produced annually in this country is approximately 30 billion
pounds.
One of the few industries capable of utilizing these large volumes
is the animal feed industry. Unfortunately, the price that can be paid
for dried whey for feeding purposes is low, often just about the
processing costs. This is because the major constituent of dried whey
*This investigation was partially supported with funds from the US
Environmental Protection Agency, Office of Research and Monitoring,
under Grant Number S800747.
**Amber Laboratories Division, Milbrew, Inc., Juneau, Wisconsin.
118
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is lactose which can be used only in a limited amount in most feeds and
must compete price-wise with other inexpensive carbohydrate and energy
sources such as molasses and corn. There is a much greater demand for
high protein ingredients in this area. This report describes the
commercial conversion of the lactose in whey into high quality protein
via fermentation.
This work, initiated and partially supported with funds from a
demonstration grant from the US Environmental Protection Agency, shows
how this can be accomplished in a unique closed-loop system producing
zero effluents. By this process one may utilize very large amounts of
whey, a potential environmental contaminant and convert it to a useful
product which can be used in an industry capable of absorbing the large
amount of material produced—that is, the animal feed industry.
PROCESS AND RESULTS
The fermentation of whey by various microorganisms has been know
and studied for years. Our own preliminary studies, reported
elsewhere,2'3 showed that the organism of choice in our process is a
strain of Saccharomyces fragilis. The conversion of lactose into yeast
cellular material is efficient and in the range of 45 to 55 percent
under non-sterile conditions. Successive scale-up has been accomplished
from shake-flasks to 14-liter fermentors to 500 gallon and 3,000 gallon
fermentors to our present operation in a 15,000 gallon tank.
Whey (acid and/or sweet) is obtained in concentrated form (45 to 50
percent solids) from cheese manufacturers. This is diluted with water,
raw whey or condensate water (as in "closed-loop" operation, to be
described shortly) to the appropriate lactose concentration. Other
medium additions include: anhydrous ammonia as the primary exogenous
nitrogen source, phosphoric acid, yeast extract and hydrochloric acid to
adjust the pH to 4.5. The medium is heated to 80 degrees C for 45
minutes and then cooled. The fermentation is carried out in a 15,000
gallon stainless steel deep-tank fermentor that is fully aerated and
jacketed. Automatic instrumentation controls pH, temperature, aeration
and foaming, as well as levels and volumes in and out. The fermentor
may be operated in a batch, semi-continuous or continuous manner. After
fermentation, the fermented whey mass is collected and processed
further. An overall schematic of the fermentation process may be seen
in Figure 1.
In a batch fermentation, starting with a seed with a viable cell
count of 1 x 109 cells per milliliter and an inoculum level of 10
percent, all the lactose is utilized in 8 hours under appropriate
conditions with an increase in cell concentration of 10 to 20 fold.
119
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ACID NH3
to
o
Eton
SEED
FERMENTOR
PRODUCT
TO ALCOHOL
RECOVERY
&/ or
WASTE
CENTRIFUGE
Figure 1. Schematic for whey fermentation process.
-------
This represents a generation time of approximately 2.0 hours and four
doublings within an 8 hour period.
The semi-continuous runs were made by drawing off 90 percent of the
fermentation broth and using the 10 percent remaining to seed the next
fermentation batch. A number of consecutive draw down batches could be
run in this manner. The only "down-time" experienced in such a
procedure is the time it takes to pump off 90 percent of the fermented
broth and to pump in fresh medium.
This "down-time" can be eliminated if the fermentation can be run
continuously, i.e., with continuous addition of fresh medium and the
removal of the fermented mass. The most efficient industrial
fermentations are of this type. This proved to be applicable in our
yeast-whey fermentation. The continuous fermentation is begun when the
cell count in the fermentation broth reaches 1 x 109 cells per
milliliter and the lactose concentration falls to 0.50 to 0.75 percent
(W/V). At this time fresh medium is added and fermented whey mass
removed at an equal rate. The fermentor may be operated in this manner
for an extended period of time, maintaining both cell count and lactose
concentration at a relatively constant level, without any indication of
contamination or buildup of metabolic products that would interfere with
the fermentation. In the smaller tanks, continuous runs of several
weeks have been accomplished. The 15,000 gallon fermentor has been
operated in this manner for shorter periods with no difficulty, other
than the initial start-up logistics. One of the early runs in the large
tank is shown in Figure 2. After initial cell growth, fresh medium is
added and the fermented whey mass removed at the rate of 1,250 gallons
per hour, which corresponds to a batch fermentation cycle of 10,000
gallons per 8 hours (dilution rate of 0.125 hours"1).
The production of Saccharomyces fragilis on whey has been done in
the United States on a small scale* and is approved for use in feeds and
foods.5 The entire fermented whey material (Yeast Fermentation
Solubles, YFS) can be used as a feed ingredient. This simplifies the
processing for it entails only the concentration of the fermentation
broth and spray drying. If the yeast cells are harvested by
centrifugation and washed, a food grade, primary grown yeast is
obtained. The proximate analysis of these products are shown in Table
1.
The use of these products as feeds or foods and the quality of the
protein they contain are indicated by rat feeding tests. Rat growth
rates using YFS and centrifuged YFS as the sole protein source in the
diet were compared with those using a casein standard. No evidence of
toxicity was noted during this period of time. From these experiments,
Protein Efficiency Ratios (PER) were calculated and found to be 1.72 for
the whole Yeast Fermentation Solubles and 2.26 for the centrifuged
121
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bo
to
10
Begin Continuous Operation
CELL COUNT
% LACTOSE
24
HOURS
36
48
Figure 2. Continuous fermentation - Saccharomyces fragi1is.
-------
Table 1. PROXIMATE ANALYSIS OF FERMENTED WHEY PRODUCTS
Crude protein
Ash
Fat
Moisture
Yeast fermented
solubles
(AMBER YFS), %
35-50
12-20
2-3
3-4
Centrifuged yeast
(AMBER NUTREX), %
45-55
6-10
2
3-4
123
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yeast.6 These values are 69 percent and 91 percent, respectively, of
that of the casein standard. Actual feeding trials are being conducted
with larger animals to determine specific values. Such tests with
cattle have proved successful and FYS material is being used in a number
of commercial feed formulations at the present time.
The quality of the protein produced by this fermentation of whey is
further indicated by amino acid analyses. In Table 2 the amino acid
composition of this yeast is compared to that of other commercially
available yeast used in feeds and foods (Brewers Yeast and Torula Yeast)
and to yeast produced by the fermentation of hydrocarbons and ethanol.
The standard amino acid FAO profile is also listed for comparison.
During the fermentation, one of the metabolic products formed is
ethyl alcohol. By changing conditions of fermentation (operating under
almost anaerobic conditions) one can increase the amounts of this
material formed. The results of one such run in our 15,000 gallon
fermentor is shown in Figure 3. After an initial period of aerobic
operation to build up cell concentration, the fermentation broth was
"spiked" with additional lactose in the form of condensed whey and the
fermentor was run under anaerobic conditions. The lactose was utilized
at a continued stready rate. However, the cell population no longer
increased, but remained at a constant level. Ethyl alcohol was produced
in larger amounts, and calculations indicate that better than 90 percent
of the lactose was being converted to this material, the rest being
metabolized for cell maintenance. The production of almost 6 percent
ethanol in this preliminary experiment indicates the potential
production of this important chemical simultaneous with the production
of single cell protein. Complicated economic factors, including energy,
production and recovery costs, as well as market values of the products,
will determine the optimum operation of the process.
In an effort to minimize waste streams from the fermentation
operation, a "closed-loop" system was designed. In this process, the
concentrated whey was diluted with condensate water derived from the
evaporation of the fermentation broths, and this was followed by the
fermentation of the whey. Theoretically, this closed-loop could be
repeated as often as new whey concentrate was added to the cycle (Figure
4). Since the entire fermentation broth is spray dried, no waste
streams are obtained; effectively, therefore, this process has zero
effluents. The fermentation results do not differ significantly whether
tap water, raw whey or condensate water is used to dilute the incoming
condensed whey. The process has been run over extended periods of time,
using this closed-loop system, with no apparent build-up of any
metabolic toxic product to inhibit the fermentation. In the overall
schematic shown in Figure 1, one can see the return of the condensate
water to the medium mixing tank.
124
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Table 2. AMINO ACID CONTENT OF VARIOUS SINGLE-CELL PROTEINS COMPARED TO FAO PROFILE
CO
en
Ami no acid
Lysine
Methionine
Valine
Leucine
Isoleucine
Tyros ine
Phenylalanine
Tryptophan
Histidine
Threonine
Total protein, %
FAO
prof i 1 e
4.2
2.2
4.2
2.8
4.2
2.8
2.8
1.4
-
2.8
AMBER
NUTREX
6.9
1.6
5.4
7.0
4.0
2.5
3.4
1.4
2.1
5.8
Brewers
yeast
6.8
1.5
4.7
5.8
3.6
2.7
3.4
1.1
2.1
5.9
Torula
yeast
8.5
1.5
5.6
8.0
6.4
4.3
5.1
-
2.2
5.1
Brit. Pet.
yeasta
7.5
1.8
5.8
7.8
5.3
3.6
4.3
1.4
2.1
4.9
Amoco
yeast*5
6.6
1.4
5.7
7.1
4.5
3.3
4.1
1.2
2.1
5.5
aFrom reference 7.
From reference 8.
-------
9 _.
to
os
Z § 3
0
-------
to
RAW
FERMENTATIO
PROCESS
10% T.S.
DILUTED
WHEY MEDIUM
1596 T.S.
EVAPORATION
PROCESS
30% T.S.
SPRAY DRY
PROCESS
CONDENSED
WHEY
45% T.S.
ALCOHOL
RECOVERY
PRODUCT
Figure 4. Closed-loop system for minimizing effluents.
-------
ECONOMICS
Preliminary cost calculations of the large scale fermentation
verify those made in the extended pilot fermentor operations.3 The cost
of the medium for the fermentation is primarily determined by the cost
of whey. While it is possible in the future this material may have a
negative value due to the necessary cost of waste treatment of pollution
abatement, at the present time, it is realistic to assume that whey may
be obtained for the cost of evaporation and/or transportation alone. If
this is the case, the medium will cost 3.0 to 5.8 cents per pound of
finished product.
The cost of production is also affected by the size of the
operation. Labor and other costs decrease on a per pound, finished
product basis as the size of the equipment and its degree of automation
and sophistication increases. However, as the capacity increases so
does the capital investment with its connected charges for depreciation,
taxes, insurance and physical facilities. A plant capable of an annual
production of 4,000 to 10,000 tons per year would cost in the range of 5
to 15 million dollars, depending on its design, and this is still
considered a small fermentation plant. Those being designed for the
production of single cell protein from hydrocarbons are in the 100,000
ton annual capacity range. Calculations using present labor, utility
and capital investment figures indicate that the feed grade material can
be produced in a plant with an annual capacity of 5,000 to 10,000 tons
for a total production cost of 12.0 to 15.5 cents per pound. This does
not take into account any credit for alcohol recovered which can be of
the order of several cents per pound, depending on the conditions for
fermentation and the yields obtained. The process looks economically
viable assuming a recovery and growth of the presently depressed animal
feed industry.
SUMMARY
Saccharomyces fragi'lis may be grown on acid or sweet whey in a deep
tank, aerated fermentor in a continuous manner on a commercial scale.
The fermentation itself has many advantages. By operating at a low pH
and with a large seed size and high cell count, contamination is not a
problem and therefore, sterile or special aseptic equipment or
techniques are not necessary. The aeration requirements are not
excessive nor is there any problem with foam control. Temperature
control, despite the rapid growth rate, is maintained with a low level
of cooling water. The medium is simple in composition, and at the
concentrations used, the carbohydrate substrate (lactose) is completely
soluble. The absence of any potentially toxic substances in the medium
simplifies harvesting. The production of a dried whole fermented whey
128
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mass (Yeast Fermentation Solubles) eliminates additional processing of
waste streams from yeast separators and increases the yield of the
fermentation. As a result of the evaporation of the whole fermented
mass prior to^drying, condensate water is obtained that can be used to
dilute incoming condensed whey and thereby operate a completely closed-
loop system with no effluents.
By varying the conditions of the fermentation, increased amounts of
ethyl alcohol can be produced and recovered but at the expense of cell
yield. However, as one expert has recently stated, "Energy
considerations could also affect the kind of SCP process. Aeration
costs could be important if energy costs continue to rise. Hence, an
anaerobic fermentation process, in which both alcohol and SCP feed are
produced, could be the process of choice."9
Food grade yeast may be produced by harvesting the yeast by
centrifugation. Indications are that some of the supernatant streams
from this process may be used in certain animal feed fractions.
The protein quality of the finished products is good, although
slightly low in the sulfur containing ami no acids, as is true of most
single cell proteins. Rat feeding tests show no toxicity and feeding
experiments with other animals show promising uses in feed rations.
The cost of production is dependent primarily on two factors—the
cost of whey and the capital investment. Efficiency demands a plant
that is highly automated and instrument controlled and of a size to have
an annual capacity of at least 4,000 to 10,000 tons of finished product.
This would represent a raw material requirement of the equivalent of 200
to 500 million pounds of raw whey. Therefore, the location of such a
facility must be near a large cheese producing area. Such an area
should have an excess of whey at little or no cost. The capital
investment is large, but must be made to allow the product to compete in
the market place.
The present and future shortage of protein has been reported
extensively, and many investigators feel one potential solution is the
production of single cell protein.9 Agricultural and industrial waste
materials may be used as substrates for such production, thereby
decreasing the immense disposal problems they present.10 Whey is a
clean, wholesome, food-grade substance, in excess supply and a potential
environmental pollutant. By the process described here, it can be
converted to a useful and needed high-protein material, the demand for
which is now present and should increase in the future.
129
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REFERENCES
1. Whey Products Institute. Cheese/Whey Production for 1972. Report
10373.
2. Bernstein, S. and T. C. Everson. Protein Production from Acid Whey
via Fermentation. Proceedings of the 1973 Cornell Agricultural
Waste Management Conference, p. 103.
3. Bernstein, S. and T. C. Everson. Protein Production from Acid Whey
via Fermentation. Environmental Protection Technology Series, US
Environmental Protection Agency. EPA-660/2-74-025. May 1974.
4. Mayer, B. M. Whey Fermentation. Proceedings of the Whey
Utilization Conference, University of Maryland. 1970. p. 48.
5. Federal Register. 28(97):4948. 1963.
6. Wisconsin Alumni Research Foundation, Madison. 1972, 1973.
7. Courts, A. Process Biochemistry. February 1973. p. 31.
8. Food Processing. July 1974. p. 28.
9. Humphrey, A. E. Current Developments in Fermentation. Chemical
Engineering. December 1974. p. 98.
10. The Wall Street Journal. February 13, 1975.
130
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TREATMENT CAPABILITIES OF AN EXTENDED AERATION SYSTEM
FOLLOWING ANAEROBIC LAGOONS TREATING MEAT PACKING WASTES
W. James Wells, Jr.*
Paula B. Wells*
Darryl D. Alleman**
INTRODUCTION
When the Monfort Packing Company began operation in Greeley,
Colorado, they discharged the wastewater from their packing plant into
the City of Greeley's sewer system. In 1964, the City of Greeley
expanded their waste treatment facilities by adding an activated sludge
plant to their trickling filter plant. However, by 1969, these combined
waste treatment facilities were organically overloaded and there were
serious odor problems. Both the City of Greeley and Monfort Packing
Company agreed that the most effective and economical solution would be
to remove the packing plant wastewater from the municipal treatment
plant and to provide a separate treatment system for the packing plant
wastewater.
Following a cost effectiveness analysis of several treatment
methods, the decision was reached to use anaerobic lagoons followed by
an extended aeration system and two polishing ponds in series with
sludge wasting to the anaerobic lagoons. Following the decision on the
method of treatment, the next problem was to find an acceptable site for
the facilities. Several sites were evaluated before an agreement was
finally reached between the City of Greeley and Weld County on the
treatment plant site. The planning agencies for the City and the County
agreed on the site as well as the City Council and County Commissioners.
*Partners, Bell, Balyardt and Wells, Architects and Engineer, Omaha,
Nebraska.
**Assistant Director, Water and Sewer Department, City of Greeley,
Colorado.
131
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A public hearing was also held before the final decision on the site was
reached.
The site that was selected was located 32,500 feet east of the
packing plant, adjacent to Lone Tree Creek, approximately one mile north
of its confluence with the South Platte River. The effluent from the
final polishing pond discharges into Lone Tree Creek.
Because of the ability of the anaerobic lagoons to provide a high
degree (80 to 85 percent) of BODs reduction on the packing plant wastes,
discussion began covering the possibility of discharging the waste
activated sludge from the City of Greeley's activated sludge plant to
the anaerobic lagoons as an effective low cost means of sludge disposal.
The City's activated sludge plant was located 4,300 feet south of the
force main to the anaerobic lagoons and about 32,000 feet west of the
anaerobic lagoons. The decision was reached to construct a 6-inch
diameter, 4,300 foot long pipeline from the City's activated sludge
plant to the 18-inch diameter pipeline from the packing plant to the
anaerobic lagoons.
The joint use of the facilities by the City of Greeley and Monfort
Packing Company made the project eligible for a grant from the US
Environmental Protection Agency (EPA).
The force main from the packing plant to the treatment plant site
including the sludge line from the City's activated sludge line to the
force main, cost $462,500, while the treatment facilities cost $581,300.
The project was bid in April of 1972, and construction was completed in
late 1973. The total grant eligible cost was $983,000 and the EPA grant
on the project was $472,890, leaving $570,910 to be financed by the City
of Greeley and repaid by Monfort Packing Company as a part of their
sewer service charge.
DESIGN BASIS FOR WASTE TREATMENT SYSTEM
Design Loadings
The following are the design loadings for the waste treatment
facilities showing the breakdown between Monfort Packing Company and the
City of Greeley.
132
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Monfort Packing Co. City Total
How, mgd 2.67 0.10 2.77
BODs, pounds per day 30,000 5,000 35,000
Suspended solids (SS), pounds
Per day 26,500 9,000 35,000
Flow Schematic
Figure 1 is a diagram showing the flow schematic for the waste
treatment facilities.
The BODs removals contemplated by the complete treatment system
were as follows:
Design Annual Average
Removals Removals
Anaerobic Lagoons, BODs 75% 80.3%
Extended aeration system 91.5% 82.0%*
Combined removal-anaerobic A.S. system 97.9% 97.0%*
Polishing lagoons, BODs 50% 60%
Treatment system removals (BODs) 98.9% 98.2%
Treatment system removals (SS) 98.9% 94.4%
BODs remaining in effluent, pounds
per day 375 188
SS remaining in effluent, pounds
per day 375 395
*July to February
Design Basis for Extended Aeration System
The design of the extended aeration system following the anaerobic
lagoons assumed the following waste characteristics of the effluent from
the anaerobic lagoons.
Flow 2.77 mgd
BODs 8,750 pounds per day
(380 milligrams per liter)
Suspended solids 5,770 pounds per day
(250 milligrams per liter)
Percent of volatile solids 74 percent
Inert volatile suspended solids 50 milligrams per liter
Average temperature 20 degrees C (75 degrees F)
Aeration time 1.33 days
133
-------
eo
LIFT STATION AT
PACKING PLANT
FORCE
MAIN
B
PACKING PLANT WASTES
BOD - 30,000 Ibs/day
Flow - 2.67 mgd
WASTE ACTIVATED SLUDGE FROM
FINAL CLARIFIERS AT CITY PLANT
BOD - 5,000 Ibs/day
Flow - 100,000 gal./day
RECIRCULATION (1.38 MGD)
WASTE SOLIDS LINE
RECIRCULATION (1.38 MGD)
LONE TREE CREEK
FINAL CLARIFIER
10 ACRES
20 ACRES
ANAEROBIC LAGOONS
BOD In - 35,000 Ibs/day
BOD Out - 8,750 Ibs/day
Flow In - 2.77 mgd
EXTENDED AERATION
BOD In - 8,750 Ibs/day
BOD Out - 747 Ibs/day
POLISHING LAGOONS
BOD In - 747 Ibs/day
BOD Out - 375 Ibs/day
Figure 1. Flow schematic of waste treatment facilities - Greeley, Colorado.
-------
Elevation of site
Beta factor
Alpha factor
Oxygen transfer-std. condition
Oxygen transfer-field cond.
Required horsepower
Aeration equipment
Mixed liquor suspended solids
(MLSS)
Waste sludge
Return sludge rate
Dissolved oxygen in aeration
basin
Number of aeration basins
Aeration basin depth
Number of clarifiers and diameter
Clarifier overflow rate
Clarifier sidewater depth
Calculated treatment effluent
Effluent BOD5
4,650 feet
0.80
°-9 n
2.9# °2/hp-hr
1.48# 02/hp-hr
320 horsepower
8-40 horsepower floating
aerators
3,000 milligrams per liter
To anaerobic lagoons
100 percent
1.0 milligrams per liter
2
9 feet
2 at 55 feet (suction type)
580 gallons per feet2 per day
10 feet
91.5 percent
32 milligrams per liter
The formulas used for calculating the required detention time,
mixed liquor suspended solids in the aeration basin and oxygen uptake as
well as the predicted BOD5 in the effluent from the final clarifier were
those developed by Dr. Ross McKinney for complete mix activated sludge
systems. The constants used in the formulas were the same as those for
domestic wastes.
Since nitrification of the effluent was not required for the
treatment system, no additional horsepower was included in the aeration
basins for this purpose.
OPERATING RESULTS
General
At the time the construction of the project was completed in the
late fall of 1973, the new water supply from the City of Greeley to
Monfort Packing Company had not been completed. The water supply at the
packing plant contained 700 to 800 milligrams per liter of sulfates
which was from wells while the City water supply contained only 10
milligrams per liter of sulfates. However, because of odor problems at
the City of Greeley1s waste treatment plant, the decision was made after
135
-------
consultation between the City, State and Federal officials to start the
system before the water supply was changed over. As would be
anticipated, odor problems occured at the anaerobic lagoons. It wasn't
until the fall of 1974 that the new water supply was extended to the
packing plant. The odor problems diminished cnsiderably; although it
has taken some time to purge the entire lagoon system of the sulfates.
The present water supply comes from reservoirs capturing snow melt
and runoff from the Rocky Mountains west of Greeley, Colorado and shows
a sulfate concentration of.less than 10 milligrams per liter. However,
the total alkalinity is also quite low (28 milligrams per liter).
Anaerobic Lagoons
The anaerobic lagoons were designed at a loading rate of 12 pounds
of BODs per 1,000 cubic feet with an assumed treatment efficiency of 75
percent. The force main from the packing plant to the anaerobic lagoons
is approximately 32,000 feet in length and there was some concern that
the temperature drop in the force main may reduce the treatment
efficiency of the anaerobic lagoons. This later proved not to be a
problem.
Figure 2 shows the concentration of BODs in the influent and
effluent from the anaerobic lagoons as well as the percent reduction of
BODs. The treatment efficiency varied from a low of 60 percent in April
and a high of 88 percent in September, with an annual average of 80.3
percent. The BODs concentration in the effluent ranged from 157 to 377
milligrams per liter, with an annual average of 295. The assumed
anaerobic lagoon BODs effluent concentration was 280 milligrams per
liter.
Figure 3 shows the concentration of suspended solids for ,the
anaerobic lagoon influent and effluent along with the percent reduction.
The assumed anaerobic lagoon concentration of suspended solids was 250
milligrams per liter.
Extended Aeration System
Figure 4 shows the concentration of BODs for the extended aeration
system influent and effluent along with the percent reduction. After
the system had stabilized by July 1, 1974, the BODs concentration in the
effluent varied from a low of 21 milligrams per liter in September to a
high of 67 milligrams per liter in January. The percent reduction of
BODs varied from 76 percent to 86 percent and averaged 82 percent.
136
-------
Co
-q
i—INFLUENT TEMPERATURE
-L^rPEF 'CENT
I .
INFLUENT
Figure 2. Anaerobic lagoon performance - BOD5.
Waste treatment facilities - Greeley, Colorado.
-------
CO
00
DATE
Figure 3. Anaerobic lagoon performance - suspended solids.
Waste treatment facilities - Greeley, Colorado.
-------
00
CD
Figure 4. Extended aeration performance - BOD5.
Waste treatment facilities - Greeley, Colorado.
-------
Figure 5 shows the concentration of suspended solids for the
extended aeration system influent and effluent along with the percent
reduction. After the system had stabilized by July 1, 1974, the
suspended solids concentration in the effluent varied from a low of 20
milligrams per liter in October to a high of 137 milligrams per liter in
February. The percent reduction of suspended solids varied from 35
percent to 82 percent and averaged 62 percent.
The design BOD5 reduction for the extended aeration system was 91.5
percent with the overall percent reduction for the anaerobic lagoon and
extended aeration system of 97.9 percent. This compared with the
percent reduction for the extended aeration system of 82.0 percent for
the period of July 1974 to February 1975, while the overall percent
reduction for the anaerobic lagoons and extended aeration averaged 97.0
percent for the same period. The low treatment efficiencies in the
months of May and June were due to low MLSS concentrations in the
aeration basin of 495 to 1,145 milligrams per liter. This occurred due
to mechanical problems with the surface aerators. The dissolved oxygen
was zero for half of the readings.
The BODs and suspended solids in the effluent from the polishing
lagoon for each of the months of record are as follows (see Figures 6
and 7):
BODs, Suspended
pounds per day solids
March 112 550
April 292 628
May 380 770
June 134 255
July 133 117
August 167 293
September 134 255
October 120 230
November 297 691
December 194 394
January 136 340
February 188 395
Average 188 395
Special Study in February 1975
We anticipated that the most difficult time for the extended
aeration system would be the winter period. Consequently, the month of
February was selected for a special study in which daily readings were
taken to determine the following parameters:
140
-------
Figure 5. Extended aeration performance - suspended solids.
Waste treatment facilities - Greeley, Colorado.
-------
iti
£! li Ji! ii Jijiiif
DATE
Figure 6. Polishing pond effluent.
Waste treatment facilities - Greeley, Colorado.
-------
CO
O
:O
;iQ,
ror^T
30^
^
r;rr
., *°%
REDUCTION p
iifi
ANAEROBlCSiaEXT
SUSPENDED SOUDS
;OVeRAL_
'ERCEIStT REDbC
ANAEROBICS 8 EXTENDED AERATION
BOD,, PERCENT REDUCTION--! -
ENDED AERATION J T
PERCENT REDUCT 6N.i iitf
4n:
|_So> i. <2
?o> =50?
:gjj...
:l'.|_-5t-
Gs
oo>
ION :
tfil
(4-K
PT
Mff
-
Uil
H
t
it
tur-
DATE
Figure 7. BOD5 and suspended solids reductions.
Waste treatment facilities - Greeley, Colorado.
-------
1. MLSS in Aeration Basin,
2. MLVSS in Aeration Basin,
3. Pounds MLSS per pounds BOD5,
4. Return Solids, milligrams per liter,
5. Return Solids as a percent of Solids in Basin,
6. Sludge Volume Index,
7. Influent Temperature
8. Influent and Effluent BOD5, SS, and
9. Percent Reduction, BODS, SS.
Figure 8 shows the data collected during February including monthly
average values. The MLSS generally varied from 2,550 milligrams per
liter to 3,625 milligrams per liter with an average of 3,036 milligrams
per liter. The pounds BOD5 per pound MLSS is at the low end of the
activated sludge range varying from 0.010 to 0.058 and averaging 0.025.
The influent BOD5 averaged 295 milligrams per liter and the average BOD
reduction in February for the extended aeration system was 83.9 percent.
The influent suspended solids concentration averaged 208 milligrams per
liter and the average suspended solids reduction was 79.7 percent during
February.
The effluent BOD5 from the final polishing pond varied from 15 to
35 milligrams per liter and averaged 21 milligrams per liter. The
suspended solids in the final pond varied from 18 to 40 milligrams per
liter and averaged 30 milligrams per liter. During the month of
February, there were only two days in which any sludge was wasted, that
being on the 20th and 28th of February when 3,216 pounds and 3,485
pounds, respectively, were wasted. The extended aeration system is
operating well within the endogenous respiration phase and thus the
solids that must be wasted is minimal. However, the monthly data shows
the MLSS were increasing from 2,940 milligrams per liter to 3,625
milligrams per liter.
The results of the winter operation of the extended aeration system
show the system to be very lightly loaded with an average ratio of
pounds BOD per pound MLSS of only 0.025. With an actual detention time
of 2.5 to 3.5 days, the surface aerators cause a considerable drop in
temperature of the wastewater in the winter pierod with a corresponding
drop in treatment efficiency. Fortunately, the polishing pond levels
out the fluctuation with an average BOD5 of 21 milligrams per liter and
an average suspended solids of 30 milligrams per liter for the month of
February.
The dissolved oxygen in the aeration basin was considerably above
the desired level of 2.0 milligrams per liter with values ranging from
7.7 to 10.0 milligrams per liter. The aerators have been placed on a
time clock to cycle their operation to save on horsepower since the
dissolved oxygen level above 2.0 milligrams per liter is of no real
144
-------
en
Date
FEB'75
2
3
4
5
6
8
9
10
n
12
13
14
15
16
18
19
20
21
22
23
24
25
26
27
28
AVG.
Anaerobic
Effluent
BODc;
251
315
192
220
219
238
157
357
300
262
287
298
307
349
278
293
360
343
303
352
304
330
354
377
323
295
S.S.
172
255
130
107
195
173
153
163
188
153
178
220
240
260
130
224
195
240
220
370
210
205
220
300
305
208
Final Clarifier
Effluent
BOOt;
47
49
45
60
_*
59
30
46
-
35
40
29
28
13
32
36
49
48
32
68
58
60
_
76
78
46
% Red
81.3
84.4
76.6
72.7
-
75.2
80.9
87.1
-
86.6
86.1
90.3
90.9
96.3
88.5
87.7
86.4
86.0
89.4
80.7
80.9
81.8
-
80
76
83.9
S.S.
52
42
54
52
.*
64
56
48
70
38
62
21
13
14
24
20
15
40
26
53
31
22
24
26
22
37
% Red
69.8
83.5
58.5
51.4
-
63.0
63.4
70.6
62.8
75.2
65.2
90.5
94.6
94.6
81.5
91.1
92.3
83.3
88.2
85.7
85.2
89.3
89.1
91.3
92.8
79.7
Pond Effluent
BODc
22
29
32
18
19
21
13
26
35
18
21
18
19
27
20
27
24
16
15
21
20
17
20
19
19
21
% Red
53.2
40.8
28.9
70.0
.
64.4
56.7
43.5
_
48.6
47.5
37.9
32.1
_
37.4
25.0
51.0
66.7
53.1
69.1
65.5
71.7
-
75.0
75.6
54.9
S.S.
32
36
26
32
38
40
32
24
32
22
34
30
24
34
33
38
28
22
18
36
26
32
30
29
27
30
% Red
38.5
14.3
51.9
38.5
_
37.5
42.9
50.0
54.3
42.1
45.2
_
_
.
-
-
-
45.0
30.8
32.1
16.1
-
-
-
-
38.5
Aeration Basin
Ana.
Eff.
Temo.°F
56
64
66
72
68
66
66
74
74
78
76
74
72
74
77
77
74
72
71
76
81
79
80
80
72.8
MLSS
2940
2780
2750
2815
2550
2876
2790
2720
2770
2825
2935
3000
3170
3080
2984
3115
3010
3070
3365
3425
3310
3500
3465
3625
3036
MLVSS
2180
2070
2040
2090
1920
2680
2050
2040
2075
2110
2195
2295
2375
2314
2333
2315
2240
2380
2540
2555
2500
2650
2630
2705
2303
#BOD/
0MLSS
.021
.015
.015
.026
_
.022
.030
.023
.025
.025
.024
.010
.026
.028
.030
.058
.023
.016
.019
.029
.028
.028
.023
0.025
Sludge
Vol ume
Index
139
137
149
138
123
149
129
127
144
144
246
186
176
224
237
209
274
272
256
250
192
263
239
231
245
195.2
* FLOW SURGE OF 100% CAUSED BOD TO RISE TO
194 MG/L AND S.S. TO 600 MG/L.
MLSS - MIXED LIQUOR SUSPENDED SOLIDS
MLVSS - MIXED LIQUOR VOLATILE SUSPENDED SOLIDS
Figure 8. Extended aeration system, special study - February 1975.
Waste treatment facilities - Greeley, Colorado.
-------
value. Consideration has also been given to closing
the system.
down one-half of
Nitrification
As indicated previously, no horsepower was provided for
nitrification of the ammonia nitrogen in the effluent from the anaerobic
lagoons. However, since the extended aeration system was operating
below its design loading, there was sufficient oxygen available for
nitrification. The following preliminary nitrogen determinations were
made using a Hach test kit.
Location
Final Clarifier
Final Pond
Final Clarifier
Final Pond
Date
8-9-74
8-9-74
9-2-74
9-2-74
Milligrams per liter
NHs-N
5
17
1
2
NO s
50
22
23
14
N02
7
6
_
—
On November 11, 1974, a complete nitrogen balance was made using
Standard Methods, with the following results noted:
Milligrams per liter
Location
Anaerobic Effluent
Final Clarifier
Effluent
Final Pond
TKN
60.4
5.7
9.5
NH3-N
48.6
3.3
2.1
NO 3
0.01
57.7
13.0
N02
0
3.4
1.7
On December 26, 1974, following colder weather and the change to a
low alkalinity water supply (total alkalinity---28 milligrams per
liter), the following results were obtained: (Adequate dissolved oxygen
was available in the aeration basin.)
146
-------
Location
Anaerobic Effluent
Final Clarifier
Ef f 1 uent
Milligrams
TKN
58
43.6
NH3-N
56
43.4
Der liter
N03
0
4.8
N02
0
0.8
Because of the continued cold weather, no further nitrogen
determinations were made of the final clarifier effluent in January and
February of 1975. However, the following nitrogen determinations were
obtained on the final pond effluent.
Date
1-15-75
1-16-75
1-20-75
1-21-75
1-24-75
1-30-75
1-31-75
2-04-75
2-08-75
2-11-75
2-13-75
2-15-75
1-18-75
2-19-75
2-21-75
NH3-N
45
35
40
30
40
44
45
45
44
45
50
48
50
53
55
NO 3
31
29
26
26
20
13
15
10
11
10
11
7.7
7
7
7
N02
7.0
6.5
6.0
6.0
4.5
3.0
3.5
2.3
2.5
2.2
2.5
1.8
1.6
1.6
1.6
Milligrams per liter
On March 24, 1975, after the weather had warmed somewhat, another
nitrogen balance was taken. The temperature of the anaerobic effluent
was 15 degrees C and the final clarifier effluent temperature was 11.5
degrees C. The dissolved oxygen in the aeration basin was well above
2.0 milligrams per liter.
147
-------
Location
Anaerobic Effluent
Final Clarifier
Effluent
Milligrams
TKN
93
48
NHs-N
81
47
per liter
NOs
0.05
29.6
NOz
0
4.9
While the temperature of 11.5 degrees C is less than optimum, there
should have been a higher degree of nitrification than was achieved.
The answer appears to be that the ability of the extended aeration
system to nitrify is limited by the low alkalinity of the raw water
supply.
Fecal Coliform Reductions
The Water Quality Control Division of the Colorado Department of
Health tested the effluent for fecal coliform during the months of
November and December 1974 and January 1975, with the following results:
Months
Fecal Coliform
MPN per 100 milliliters
November 1974
December 1974
January 1975
<100
< 22
<100
The average detention time in the polishing ponds was approximately
45 to 60 days.
SUMMARY
An extended aeration system following an anaerobic lagoon does not
behave a great deal differently than an extended aeration system
treating domestic wastes, with the exception that consideration must be
given to the oxygen demand of sulfides in the anaerobic lagoon effluent.
Further, if nitrification of the ammonia nitrogen is required, adequate
oxygen must be included to nitrify the NH3-N. In addition, the
alkalinity of the water becomes critical for a nitrification system.
148
-------
Since 7.0 milligrams per liter of alkalinity as CaC03 are required
for each milligram per liter of N03 formed, there is an insufficient
quantity of alkalinity in the water to nitrify the NH3-N in the
anaerobic effluent. If and when nitrification is required, the addition
of some form of alkalinity will be necessary.
Also, if nitrification is to be a requirement in a future extended
aeration system, the aeration basins would have to be designed to
conserve heat by making them deeper and by changing from a surface
aeration system to either static tube aerators or a diffused aeration
system. ^In our opinion, this type of aeration system would be required
to minimize the heat loss that occurs from surface type aerators.
As an example, if the temperature of the influent to the extended
aeration system were 75 degrees F and the air temperature is 0 degrees F
with a 20 mile per hour wind, with a sidewater depth of 15 feet, with a
detention time of 24 hours, and with surface aerators, the water
temperature in the aeration basin would drop to 6 degrees C (43 degrees
F) or less.
The study showed that a treatment system consisting of anaerobic
lagoons followed by an extended aeration system is capable of
accomplishing BODs reductions in the range of 95 to 98 percent, with an
average of 97 percent. The corresponding suspended solids reductions
ranged from 72 to 97 percent, with an average of 89.5 percent. The
extended aeration system itself accomplished BODs reductions of 76 to 86
percent with an average of 82 percent. The corresponding values for
suspended solids showed a range of 35 to 81 percent with an average of
62 percent. The overall treatment system efficiency for BODs including
the polishing lagoons varied from 97.7 to 99.2 percent, with an average
of 98.2 percent. The corresponding values for suspended solids ranged
from 88.0 percent (influent suspended solids only 719 milligrams per
liter) to 97.3 percent and averaged 94.4 percent.
Odors from the anaerobic lagoon continue to be a problem due in
part to the untimely start up of the lagoons, while the high sulfate
concentrations existed in the water supply. The system still shows 80
milligrams per liter of sulfates in the effluent of the polishing pond,
even though the raw water only has 10 milligrams per liter of sulfates.
During the special study during the month of February, the pounds
BODs and suspended solids per 1,000 pounds live weight kill (LWK) for
the extended aeration system and the complete treatment system were as
follows: (The values for February 6 and 7 were not included due to an
operational problem with loss of MLSS in aeration basin.)
149
-------
BOD5, pounds per 1,000
pounds LWK
Suspended Solids, pounds
per 1,000 pounds LWK
Extended
Aeration
Effluent
0.144
0.120
Polishing
Pond
Effluent
0.106
0.152
For the design of an extended aeration system following anaerobic
lagoons, consideration should be given to a polishing pond which serves
as a buffer to even out the occasional and almost inavoidable upsets
that can and do occur in an extended aeration system. The polishing
pond also serves to reduce the fecal coliform concentrations to less
than 400 MPN per 100 milliliters.
150
-------
A PROGRESS REPORT ON A SYSTEMS APPROACH
TO EFFLUENT ABATEMENT IN HAWAII
Richard T. Webb*
INTRODUCTION
The major concepts for a waste water management system in Hawaii
were first described at the Fourth National Symposium on Food Processing
Wastes in 1973. This report will outline some of the successes and
failures resulting from the implementation of these concepts on a full-
scale production basis.
Quality Measurement of Harvesting Operations
Early experiments to determine the quality-effectiveness of new
harvesting methods and machinery with respect to minimal soil pick-up
indicated that traditional harvesting test methods lacked critically
important objectivity. It became necessary to devise methods which
avoided the "test bias" or "halo effect" which occurs when a test is run
on an innovative production operation.
Prototype harvesting machinery had shown in early tests a soil
pick-up of about 5 percent of the weight of cane compared with 15
percent or more with the conventional methods. New machines based on
the prototype seldom achieved the required 5 percent level during
production runs and questions arose as to the actual amount of entrained
soil in the harvested cane. Test data for the new harvesting method had
been manually determined by collecting several samples of a few hundred
pounds each and making a separation of soil, cane and leaves. The
results were erratic and contradictory and varied with rainfall and
trash quantities.
*Assistant to the President for Environmental and Technical Affairs,
Hilo Coast Processing Company, Pepeekeo, Hawaii.
151
-------
A revised method was developed which has several advantages:
1. Sampling could become routine regradless of the type of test
and analysis required, thus reducing test bias;
2. Moisture effects could be eliminated, thereby minimizing the
effect of rainfall on the test data; and
3. The effect of variations in the quantity of leafy trash could
be minimized, although a minor systematic error remained, for
which compensation was made.
The new method consisted of subsampling test cores of harvested
material which were routinely taken for the purpose of determining the
amount of sugar to be allocated to each harvest field. The core-
sampling technique (see Figures 1 through 4) had been approved several
years earlier by the US Department of Agriculture for use in the
Hawaiian Sugar Industry and is statistically accurate.
The test-core subsamples were analyzed for fiber and were then
ashed at 500 degrees C for 24 hours for soil determination, expressed as
bone dry ash. A correction of 0.4 percent for ash due organic matter
(cane fiber) was then made to bring the samples to the same relative
basis. This introduced a small error considered to be of lesser
magnitude than the sampling and analytical error.
It is known that ashing at 500 degrees C causes a loss of water of
hydration of the soils in the area, which loss is about 27 percent
(Table 1). However, field data were collected on the basis of ashed
soil in order to provide a simple analytical procedure applicable to all
samples under all conditions, and which eliminated the possibility of
errors of sampling and analysis that often occur in routine moisture
analyses of field cane. Of primary importance was the requirement for a
sampling and analytical method which provided objective low-cost high-
volume measurement data for relative quality of performance
determinations between different harvesting methods under all conditions
of weather and terrain. These data, by correcting for loss of water of
hydration upon ignition, are also being used for estimating the soil
disposal tonnages and the necessary size of wastewater treatment
facilities.
The quality measurements sought are intended to provide a basis for
selection of the optimum cane harvesting system for the Hilo Coast of
Hawaii as described at the Fourth Symposium. The new system, including
transportation and discharging facilities at the factory, is called
"Cane Materials Handling", hereafter abbreviated to CMH. The old system
is called "conventional" or "long cane".
152
-------
---
Figure 1. Core sampling station.
Figure 2. Hydraulic drive - tube
coring device.
-------
::
Figure 3. Core tube approaching
sub-sampling device.
Figure 4. Sub-sampler in action,
-------
Table 1. LOSS OF WEIGHT UPON IGNITION OF
TYPICAL SOILS AT PEPEEKEO, HAWAII
(March 1975)
Sample Number
23
24
25
26
27
28
29
30
32
33
34
Average
Weight loss, %
26.25
27.59
27.38
26.91
27.08
27.17
26.03
28.29
27.29
26.34
27.10
27.04
155
-------
Inspection of Table 2 shows typical data illustrating differences
between the old and new systems, in which the weekly average for CMH
approaches the target value of 4 percent ash, which is estimated to be
the amount of ash that represents an economically achievable level for
the planned wastewater treatment facilities. Table 3 illustrates the
type of information obtained by operating the old and new systems in the
same field (Field F60-A). Note that the CMH on Day 3 (Tuesday) does
achieve the required quality of performance with a reasonably good
tonnage of gross material.
Table 4 is a comparison of four of the CMH techniques which
provided the summary data for Table 3. There are at present only two of
the new harvester-cleaners (pick-up cleaners) in operation. Machine 1
is equipped with blowers for leafy trash removal, but without special
dirt-removal equipment. Machine 2 is a second-generation machine with
dirt-removal facilities but without blowers. Machine 3, not completed
at April 2, 1975, will have both the blowers and improved dirt-removal
rolls. The "burned", "unburned", notations refer to whether or not the
cane was burned before harvest to reduce the amount of leafy trash.
Tables 2, 3 and 4 are illustrative of some of the combinations of data
available from the recently developed technique for sampling and
analysis of cane harvested by various methods. The technique is simple,
reproducible and low cost, and allows testing to occur on routine
production operations without interposing special conditions for
testing. The accuracy of the method is satisfactory for measuring the
relative performance of machinery harvesting a product difficult to
sample in tonnage quantities. The absolute accuracy of the method, as
it is described above, is probably not satisfactory.
Transportation and Cane Unloading System
The earlier developmental work on the transportation system
envisioned an infield transporter, a mobile trans-loader at the roadside
and a truck-trailer with a 30-ton capacity. The trans-loader was found
to be an inefficient device which required too much time for positioning
and unloading, dropped too much chopped cane at the roadside and tended
to dig itself into the mud. This machine has been replaced by modified
infield transporters which have a pivoted extendable box for loading
directly into the trucks at roadside.
A completely new type of cane hauling unit for the Hilo Coast is to
replace the conventional open-frame side-unloading semi-trailer trucks.
The new units, when the program is fully implemented in 1977 will
comprise 35 double trailer units with 12 cab-over-engine (COE) tractors.
Ten of the trailer units (see Figure 5) have been delivered and will
operate temporarily with conventional tractors until the COE units
arrive.
156
-------
Table 2. FACTORY SUMMARY, WEEK ENDING 2/22/75
(tons gross)
WAINAKU (LONG CANE)
Day
1
2
3
4
5
6
7
WK
TD
Material
1,538.64
2,825.74
2,716.15
2,594.29
2,981.30
2*767.22
483.61
15,906.95
100,883.33
% Ash
11.87
11.69
11.44
11.83
11.47
8.52
10.09
11.04
9.45
Tons ash
182.65
330.34
310.66
306.87
341.85
235.70
48.80
1,756.87
9,532.48
Unaccounted
329.28
20.98
278.24
25.00
27.55
680.05
3,385.21
PEPEEKEO (LONG CANE)
Day
1
2
3
4
5
6
7
WK
TD
Material
2,263.48
2,589.44
2,010.00
2,859.58
2,316.55
1,966.06
445.22
14,450.33
122,274.44
% Ash
8.67
7.91
8.77
10.45
9.51
8.40
8.55
8.99
8.76
Tons ash
196.15
204.72
176.26
298.93
220.29
165.19
38.05
1,299.59
10,707.17
Unaccounted
25.65
25.65
684.33
PEPEEKEO (CMH CANE)
Day
1
2
3
4
5
6
7
WK
TD
Material
0.00
236.99
361.62
282.60
285.12
251.20
298.17
1,715.70
9,610.87
% Ash
0.00
4.13
4.52
5.76
5.37
4.78
4.48
4.84
6.24
Tons ash
0.00
9.79
16.35
16.29
15.31
12.00
13.35
83.09
599.70
Unaccounted
0.00
347.65
157
-------
FIELD F 27A
Table 3. PEPEEKEO FACTORY, WEEK ENDING 3/8/75
(tons gross)
FIELD F 60A-CMH
Day
1
2
3
4
5
6
7
WK
TD
Material
0.00
457.78
1,484.47
1,596.05
1,054.72
1,109.12
437.31
6,139.45
6,139.45
% Ash
0.00
5.30
8.43
8.79
8.10
8.15
8.59
8.19
8.19
Tons ash
0.00
24.26
125.11
140.34
85.40
90.37
37.58
503.06
503.06
Day
1
2
3
4
5
6
7
WK
TD
Material
0.00
131.78
225.82
264.07
235.41
223.99
0.00
1,081.07
10,811.25
% Ash
0.00
5.45
3.52
5.52
6.04
5.29
0.00
5.16
6.12
Tons ash
0.00
7.18
7.96
14.58
14.23
11.84
0.00
55.79
661.25
FIELD F 27B
FIELD V 55A
Day
1
2
3
4
5
6
7
WK
TD
Material
1,056.14
903.26
0.00
0.00
0.00
0.00
0.00
1,959.40
5,770.59
% Ash
5.45
6.65
0.00
0.00
0.00
0.00
0.00
6.00
7.22
Tons ash
57.56
60.05
0.00
0.00
0.00
0.00
0.00
117.61
416.62
Day
1
2
3
4
5
$>
WK
TD
Material
0.00
71.49
0.00
0.00
0.00
338.69
0.00
410.18
410.18
% Ash
0.00
4.84
0.00
0.00
0.00
9.88
0.00
9.00
9.00
Tons ash
0.00
3.46
0.00
0.00
0.00
33.45
0.00
36.91
36.91
21.70 tons gross unaccounted.
FIELD F 60A
Day
1
2
?•
5
6
7
WK
TD
Material
0.00
991.67
2,190.15
1,518.40
1,558.04
1,804.12
220.96
8,283.34
8,801.95
% Ash
0.00
6.43
8.61
6.62
9.10
9.47
9.31
8.28
8.43
Tons ash
0.00
63.76
188.60
100.52
141.79
170.85
20.57
686.09
741.92
FIELD P450
Day
*
3
4
5
6
7
WK
TD
Material
394.17
0.00
0.00
0.00
0.00 $
0.00
0.00
394.17
2,750.69
% Ash
5.58
0.00
0.00
0.00
0.00
0.00
0.00
5.58
7.56
Tons ash
21.99
0.00
0.00
0.00
4 0.00
~ 0.00
0.00
21.99
209.07
180.07 tons gross unaccounted.
20.18 tons gross unaccounted.
158
-------
Table 4. COMPARISON OF CMH EQUIPMENT - WEEK ENDING 3/8/75
Ol
Day
1
2
3
4
5
6
7
WK
TD
Description
Tons gross
% ash
Tons ash
Tons gross
% ash
Tons ash
Tons gross
% ash
Tons ash
Tons gross
% ash
Tons ash
Tons gross
% ash
Tons ash
Tons gross
% ash
Tons ash
Tons gross
% ash
Tons ash
Tons gross
% ash
Tons ash
Tons gross
% ash
Tons ash
Legend: Code 4 * b
Code 6 « b
Code 4
•
274.10
2.66
7.30
Machine 1
Code 5
Code 6
63.74
5.55
3.54
63.74
5.55
3.54
63.74
5.55
3.54
Code 7
113.75
5.06
5.76
113.75
5.06
5.76
165.54
5.19
8.59
own/burned code 5 = unb
lown/unburned Code 7 = unbl
Suni/avq.
63.74
5.55
3.54
113.75
5.06
5.76
177.49
5.24
9.30
503.38
3.86
19.43
Machine 2
Code 8
235.41
6.04
14.23
235.41
6.04
14.23
2094.19
5.17
108.23
Code 9
68.04
5.35
3.64
225.82
3.52
7.69
264.07
5.52
14.58
110.24
5.52
6.08
668.17
4.83
32.26
8213.68
6.50
533.59
own/burned Code £
own/unburned Code £
Sum/avg.
68.04
5.35
3.64
225.82
3.52
7.69
264.07
5.52
14.58
235.41
6.04
14.23
110.24
5.52
6.08
903.58
5.15
46.49
10307.87
6.23
641.82
Ml - M2
variance
0.20
-0.46
0.09
-2.37
- burned
I = unburned
-------
Figure 5. Double trailer unit for hauling cane,
160
-------
A hydraulically-operated side dumping device 75 feet long has been
installed at Papaikou. This dumper will tip the complete cane hauling
truck-trailer assumbly to an angle of 30 to 55 degrees (adjustable).
The sides of the trailers unlatch before tilting and permit the CMH cane
to be discharged to the storage deck at the mill (Figures 6 and 7).
Note the heavy-duty hold-down clamps for the trailers. The trailers
will carry only cane harvested by the new machines.
Progress of the Abatement System
Harvesting—The first new harvesting pick-up cleaner machine began
production operation about May 1, 1974. It began operations under very
favorable conditions in that 1974 was a very dry year, especially from
June to November, with only 120 inches of rain in the Hilo area. Soil
loadings were nearly acceptable, though erratic. However, substantial
rain returned in November just as the second machine began operations,
and the quality of the CMH cane suffered severely.
The problem of soil entrainment, with its severe effect on the size
of wastewater treatment facilities required, prompted re-evaluation of
harvesting methods and revisions of old and new machines. A
conventional V-cutter was modified with two rotating ground knives added
on each side to replace the usual stationary ground knife (see Figure
8). The machine failed, first, because the stability of the cutter
moving across the uneven terrain was insufficient to avoid digging into
the soil, especially on moderate slopes and, second, because the
operator could not get enough traction to move through the cane in wet
weather. A typical stand of Hawaiian cane is shown in Figure 9. Note
that the tangled mat of lodged (fallen) cane in the photo is about three
feet deep. Some of the fallen cane clings to the ground like a creeping
grass (which it is) and requires a substantial amount of power to
dislodge it.
Modifications were made to the second pick-up cleaner by adding
dirt-removal points, especially a set of pronged rolls developed by the
US Department of Agriculture in Florida. These rolls, together with bar
screens and conveyor changes have improved performance somwhat but not
enough to meet the required objective of a maximum 4 percent ashed soil
per ton of net cane. (Net cane is cane with no leaves, tops, roots,
soil, rocks or other extraneous matter.)
Figure 10 shows the second pick-up cleaner harvester. The pick-up
assembly has been split into two conveyors to provide a drop-out point
for dirt at the transfer point between the two conveyors. The drums
above the conveyors are to improve pick-up by compression of the cane
mat. Figure 11 is taken immediately above the track of Machine 2 and
shows dirt dropping out below the bar screen and Florida rolls.
161
-------
Figure 6. Cane storage deck at mill.
Figure 7. Storage deck.
162
-------
Figure 8. Vee cutter - rotary.
Hilo Coast Processing Company, May 1974,
(Continued next page.)
163
-------
Figure 8 (continued). Vee cutter - rotary.
Hilo Coast Processing Company, May 1974.
Figure 9. Hawaiian sugar cane,
164
-------
Figure 10. Cane pick-up cleaner harvester.
Figure 11. Close-up of harvester.
165
-------
Machine 3 will represent a shift in harvesting philosophy on the
Hilo Coast in that it will contain two cutter heads (ground knives),
mounted just ahead of the pick-up chains. Tests made on a modification
of an old experimental machine have indicated that it may be possible
and advantageous to eliminate the V-cutting stage of harvesting. The
negative factors are increased weight and complexity of the machine and
reduced rate of production. The advantage is the possibility that an
acceptable level of soil in cane may be achieved, a factor which
completely outweighs disadvantages which were earlier thought to be
insurmountable. The renewed emphasis on quality of raw material in
order to minimize end-of-pipeline treatment at the factory has caused a
significant change in operational objectives.
Cane Dry Cleaning—The cane dry cleaners at Papaikou and Pepeekeo
became operational in 1974 and it quickly became evident that undue
optimism had prevailed during the design of these units. In dry
weather, with CMH cane, the cleaners worked moderately well. In wet
weather, or with long cane, they failed miserably, hence, these two
cleaners are being modified to permit dry cleaning for the leafy trash
followed by wet cleaning for the remaining soil.
However, the dry removal of trash proved to be unexpectedly
efficient in two ways. First, the method of dry removal appears to be
much more efficient with respect to the quantity of trash removed than
the conventional wet cleaning system. It is evident that no water
should be used prior to the removal of trash by air blast. Second,
large quantities of soil (up to 50 percent in early tests) are removed
by and with the leafy trash. Some of the soil is occluded by the leaves
and some is held by the rough surfaces of the leaves. This feature has
provided an unexpected means of lowering cane wash-water suspended
solids by a substantial, but variable, amount. The next phase will be
to conduct an economic analysis to determine whether or not the cane
trash should be washed, dewatered and burned for electric power
generation or hauled away to waste land areas for disposal and eventual
reclamation of the land for agriculture. It has become apparent that,
with additional study and experience, it should be possible to select a
combination of modes of operation of the harvesting equipment and of the
cane cleaners to provide the optimum economic balance of the use of the
components of the total pollution abatement system.
Electric Power Generation—This
segment of the abatement system has
basis for nearly a year and is
been in operation on a commercia1
furnishing about 20 percent of the electrical power for the Island of
Hawaii. At the time of writing the generation of power at full load
using fibrous waste alone occurs on a partial basis pending final
implementation of the shut-down schedule for the old factories, at which
time more fibrous fuel will become available for the new power plant at
Pepeekeo.
166
-------
Indeed, the capability of the new installation is such that
combustible municipal solid waste could be burned with ease once the
non-combustible wastes were separated. The type of boiler installed at
Pepeekeo, because of its requirement for larger than normal furnace
volume to burn waste cane fiber, is well suited for burning other kinds
of solid waste.
Figure 12 shows a portion of the fibrous fuel storage for the
boiler and Figure 13 shows the 20,000 KW electric generator driven by
high pressure steam from the boiler.
Effect of Certain Operational Parameters
The major independent variable affecting the total program is
rainfall. This single element controls the amount of suspended soilds
(soils) to be handled by all operations including the sugar processing
and electric power generation. Several charts and graphs illustrate
this factor rather vividly. Table 5 is the 75-year record of rainfall
for a rain guage near the center of the cane farming area involved in
the harvesting phase of the pollution abatement system. The lower
section of the chart showing highs, lows and averages is of particular
interest as a guide to the probably limits of the ' problem. This is
followed by Figure 14, which shows, in tabular and graphic form, the
distribution of rainfall in the area for the years 1969 to 1971, with a
grouping of light, medium and moderate to heavy rainfall.
Fortunately, the period for November 25, 1974 to December 27, 1974
contained well-defined intervals of light, medium and moderate rainfall.
This period coincided with the implementation on a production basis of
the new procedures for determination of ashed soil in harvested cane.
Compilation of the raw data in terms of the amount of ash (in tons) per
ton of pol (sucrose) in the harvested cane provided a useful ratio for
the determination of the effect of the amount of rainfall on the quality
of the harvested material from the conventional harvesting method and
the new CMH system.
The tons ash per tons pol ratio is useful because the amount of
sugar in the cane, per acre, is reasonably constant for a particular
field, hence provides a base for comparison of different techniques.
The sugar content (pol) of the harvested cane is routinely determined by
the core-sampling method described earlier and the data were available
on a comparable basis, sample by sample. Inspection of Table 6, Dry Ash
In Harvested Cane, shows that, for the period measured, the soil
reduction efficiency of the new CMH system decreased with increasing
rainfall and finally failed altogether. This situation resulted in the
re-evaluation of harvesting operational philosophy which has-been
described. Note that Table 6 is based on "corrected rainfall".
167
-------
Figure 12. Storage of fibrous fuel.
Figure 13. Electric generator.
168
-------
Table 5. 1900 TO 1974 MONTHLY RAINFALL DATA - PAPAIKOU MAKAI STATION
Year
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1933
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
TOTAL
AVG.
HIGH
LOW
Jan
1.99
10.98
4.75
8.91
32.52
2.58
6.36
8.13
11.86
9.61
26.87
22.09
0.97
36.72
10.97
5.55
14.05
24.29
27.13
6.91
5.77
63.88
32.96
59.14
3.47
14.12
3.56
12.91
8.46
9.10
5.64
2.66
29.02
24.79
14.45
8.25
5.35
28.36
22.10
22.88
1.06
6.41
1.64
8.99
3.43
2.87
23.62
3.30
6.12
33.17
9.71
9.06
18.83
0.15
4.93
12.84
9.94
11.46
2.60
10.07
22. 12
3.17
2.72
1.66
16.60
9.80
11.80
9.39
5.53
13.31
6.06
13.87
10.42
3.69
6.27
966.72
12.89
63.88
0.15
Feb
5.81
10.91
4.51
11.72
12.83
8.61
2.69
17.91
26.33
12.70
4.62
18.18
18.58
9.23
4.43
14.58
2.58
4.54
41.10
8.26
6.19
5.89
29.50
8.73
9.08
2.49
6.56
4.14
5.48
15.75
4.38
9.08
30.95
14.18
4.77
26.15
4.40
8.34
14.65
22.37
5.05
1.62
5.45
8.84
20.30
6.43
9.33
3.26
10.16
8.45
25.47
27.05
8.18
11.75
15.33
23.99
37.90
7.71
4.30
11.82
16.23
24.00
5.33
2.21
17.28
5.56
6.21
8.90
13.37
52.24
1.92
7.86
19.56
6.11
8.28
920.70
12.28
52.24
1.62
Mar
5.66
35.83
81.29
7.63
1.62
3.65
3.21
17.78
7.54
38.69
21.44
13.28
16.54
10.34
11.24
4.10
15.81
29.14
39.88
17.35
36.65
5.74
69.73
35.86
8.54
34.70
1.71
17.98
5.27
20.29
12.69
2.28
4.70
7.20
3.12
8.45
19.51
28.05
31.17
39.89
4.41
9.63
43.31
8.08
1.76
25.54
12.56
18.11
34.97
12.10
6.81
17.76
18.02
21.56
17.09
10.24
16.88
3.95
5.56
10.46
9.37
5.90
12.13
16.93
21.10
, 6.81
6.44
9.33
11.84
36.76
6.83
15.24
1.52
21.48
15.23
1.276.26
17.02
81.29
1.52
Apr
6.37
13.35
13.97
23.86
38.04
8.57
11.13
6.66
23.29
11.80
14.15
20.83
25.78
15.38
11.04
31.90
16.22
18.28
36.00
6.36
8.36
13.99
18.69
34.15
34.91
15.09
2.15
1.0. 82
7.23
13.27
30.82
10.09
12.02
10.90
10.03
10.75
15.37
13.09
27.66
20.54
3.87
4.85
19.59
8.91
14.34
13.51
12.97
8.75
12.89
7.65
28.37
5.81
8.99
4.63
3.12
18.32
7.96
21.89
5.88
9.93
16.95
7.34
4.32
34.54
11.50
18.51
5.71
20.30
33.13
17.94
32.04
27.15
24.71
8.56
21.50
1,179.04
15.72
38.04
2.15
May
16.85
3.34
27.16
9.31
8.78
10.04
10.77
8.03
13.17
16.16
17.56
19.23
9.34
9.65
32.53
4.50
30.95
8.22
29.31
7.61
2.11
4.36
11.32
14.75
6.87
15.18
7.76
10.37
10.16
3.84
11.51
6.14
13.06
10.02
14.08
3.75
11.88
13.79
14.70
4.62
5.41
17.84
9.53
5,14
13.05
1.19
2.87
10.62
13.11
4.43
18.65
3.82
9.33
11.97
11.84
10.71
16.02
8.88
9.28
8.58
12.82
9.66
15.46
15.47
30.24
17.54
6.52
12.22
2.85
7.11
29.51
6.96
7.28
9.18
9.75
867.62
11.57
32.55
1.19
Jun
3.42
3.01
6.67
5.85
9.60
10.49
7.24
14.51
9.77
10.39
14.74
14.99
11.89
11.48
29.24
13.16
15.57
9.85
12.59
6.72
5.04
3.17
3.64
14.45
4.31
12.09
4.10
6.11
7.27
2.92
20.69
3.91
7.55
5.82
9.30
7.85
5.57
15.51
6.75
11.08
4.65
14.05
6.17
15.27
5.95
9.01
4.06
6.04
4.60
3.48
4.34
4.31
10.18
4.98
7.03
5.90
9.41
4.66
7.65
4.25
6.58
5.83
3.49
11.10
6.07
9.04
7.52
7.79
10.01
2.65
7.56
3.38
6.02
5.10
4.92
611.86
8.16
29.24
2.92
Jul
11.27
6.01
17.18
26.64
20.36
11.63
14.44
10.41
11.75
18.76
14.47
13.64
8.07
7.48
32.28
13.36
12.26
9.71
34.73
10.34
10.98
10.30
7.64
15.22
18.11
4.10
5.20
14.52
16.22
14.25
9.41
15.99
12.43
4.30
8.47
8.52
14.11
19.32
3.74
13.48
11.40
7.52
6.41
11.57
14.10
4.86
12.03
9.66
8.19
8.88
9.10
12.26
7.08
5.21
14.59
10.74
5.92
12.62
15.16
6.70
7.78
8.34
7.81
15.15
8.09
10.99
17.62
18.85
7.68
12.70
14.55
7.53
11.11
6.24
7.48
887.38
11.83
34.73
3.74
Auq
13.57
8.57
25.11
9.54
17.10
17.12
25.60
44.50
15.81
7.42
18.85
11.04
9.99
10.35
48.67
6.57
24.00
4.11
18.03
14.20
8.76
11.25
11.97
17.20
17.72
17.70
17.57
15.07
9.38
8.62
21.30
13.40
6.89
5.00
5.71
6.92
27.42
14.99
6.26
6.21
23.88
17.51
12.14
9.95
7.41
14.26
7.00
14.79
7.44
7.80
6.17
11.24
7.31
5.84
15.45
9.31
17.08
31.22
21.05
8.71
13.31
8.75
5.98
8.57
8.00
4.46
10.12
22.52
8.91
25.28
25.23
3.41
13.99
3.25
5.39
1.022.22
13.63
48.67
3.25
Sep
8.13
6.97
16.29
17.08
10.16
24.39
9.59
37.82
20.83
11.15
7.47
21.41
8.20
6.57
39.02
8.26
16.29
4.54
9.70
13.16
15.01
8.01
21.21
25.18
10.69
12.59
9.97
12.49
11.30
4.24
15.04
19.97
6.05
8.12
13.67
9.03
21.97
7.41
4.69
6.48
9.97
16.45
6.32
7.99
8.39
5.60
5.65
10.60
7.92
6.97
4.71
3.18
7.94
4.16
9.80
6.72
2.80
3.16
7.94
8.84
14.29
7.99
11.75
13.07
14.67
6.30
10.57
6.17
12.40
11.56
7.89
8.65
6.89
10.95
2.43
830.84
11.08
39.02
2.43
Oct
23.65
15.28
19.23
10.06
5.20
12.34
6.67
19.29
16.65
11.94
9.79
10.50
23.91
4.44
11.50
21.59
13.62
6.06
11.92
12.47
19.99
18.19
11.73
17.84
26.37
5.14
7.12
8.27
13.43
4.70
10.33
9.86
2.74
2.94
16.91
7.87
16.19
11.14
9.20
9.55
17.93
25.91
10.39
3.25
13.93
6.88
9.49
13.97-
15.08
10.71
10.42
24.24
10.52
6.95
9.40
6.22
14.69
20.40
15.20
4.67
14.07
28.68
2.87
13.75
11.42
8.57
17.04
6.55
6.57
3.02
10.09
8.87
15.00
9.91
7.03
909.31
12.12
28.68
2.74
Nov
18.36
51.04
23.42
20.02
8.91
35.99
18.45
13.24
9.28
4.65
15.51
19.37
17.13
27.88
20.63
51.99
25.10
23.08
24.14
12.37
11.49
35.12
27.17
10.12
10.65
11.24
5.00
14.93
7.24
11.95
19.43
14.04
10.70
2 86
8.50
18.56
7.65
14.93
14.59
11.57
9.21
8.48
3.59
3.17
14.62
13.92
5.86
16.13
18.45
11.74
9.44
14.58
13.63
7.03
11.61
15.09
23. ,66
11.47
15.09
29.78
15.16
15.55
6.35
11.77
24.67
21.26
18.98
29.67
6.78
7.28
7.30
26.37
19.10
32.03
9.39
1,216.49
16.22
51.99
2.86
Dec
2.01
20.11
26.04
8.18
4.71
15.92
19.47
6.05
18.23
27.39
18.03
18.05
21.05
13.52
15.60
14.05
45.48
8.77
28.73
5.84
14.93
31.12
3.90
41.27
4.56
1.21
15.85
49.06
26.88
14.48
6.79
5.77
14.87
2 39
18.31
2.83
39.71
13.19
13.29
2.68
3.60
12.37
15.09
12.41
20.42
18.69
48.17
25.09
25.90
16.44
14.20
16.84
8.58
8.97
49.96
7.77
9.99
20.37
3.70
14.17
4.4S
17.99
3.06
1.64
9.86
17.84
13.67
20.96
27.45
U.77
43.00
35.05
4.47
13.27
22.80
1,250.33
16.80
49.96
1.64
Monthly
Total average
116.79 9.73
185.40 15.45
265.62 22.14
158.80 13.23
169.88 14.16
166.33 13.86
135.62 11.30
204.33 17.03
184.51- 15.38
180.66 15.06
183.40 15.29
202.61 16.88
171.45 14.29
163.40 13.62
267.15 22.26
189.61 15.80
231.93 19.33
150.59 12.55
313.26 26.11
121.59 10.13
145.28 12.11
211.02 17.59
249.46 20.79
293.91 24.49
155.26 12.94
145.65 12.14
86.55 7.21
176.67 14.72
128.32 10.69
123.41 10.28
168.03 14.00
113.19 9.43
150.98 12.58
go 53 a 21
7O * 3£ O • fc I
127.32 10.61
tifl 0-9 a QI
liO.OJ 7> 7l
189.13 15.76
188 1? 15 fifl
iwO • i C * ** • "O
168.80 14.07
171.35 14.38
100 44 fl 37
1WV.1**? O**'/
142 64 11 fi9
Jl~fc.Q*F AX.Q7
139.63 11.64
103 57 ft S3
lUW.Wf OmOJ
137.70 11.48
122.76 10.23
153.61 12.80
140.32 11^69
164.83 13.74
131.82 10.99
147.89 12.32
150.15 12.51
128.59 10.72
93.20 7.77
170.15 14.18
137.85 11.49
172.25 14.35
157.79 13.15
113.41 9.45
127.98 10.67
153.13 12.76
143.20 11.93
81.27 6.77
145.86 12.16
179.50 14.96
136.68 11.39
132.20 11.02
172.65 14.39
146.52 12.21
201.62 16.80
191.98 16.00
164.34 13.70
140.07 11.67
129.77 10.81
120.47 10.04
11.948.77
159.32 13.28
313.26 26.11
81.27 6.77
169
-------
210
200
a:
5
60
50
40
30
20
10
0
RAINFALL 1969 THRU 1971. PAPAIKOU, ELEVATION 200 AND 1,400 FEET.
From
-i o.
0.
0.
0.
00
26
51
76
1.01
1.
1.
1.
26
51
76
2.01
2.
2.
2.
3.
3.
3.
26
51
76
01
26
51
3.76
4.
4.
4.
01
26
51
4.76
5.01
5.
5.
26
51
5.76
6.01
6.26
6.
50
6.76
Over
To
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
2.25
2.50
2.75
3.00
3.25
3.50
3.75
4.00
4.25
4.50
4.75
5.00
5.25
5.50
5.75
6.00
6.25
6.50
6.75
7.00
7.00
Elevation
1969
200
200
53
16
18
16
9
5
5
2
1
2
2
1
1
2
1
2
1
1
1
3
1,400
192
51
22
20
13
12
11
5
5
4
2
3
2
1
2
4
1
2
2
1
1
1
8
1970
200
205
58
34
19
17
5
6
4
3
3
1
1
1
1
1
1
1
1
1
2
1,400
178
51
43
20
19
12
6
7
4
4
2
1
4
i
2
2
2
1
1
1
4
1971
200
235
43
33
16
10
4
5
2
1
6
3
1
1
1
1
1
2
1,400
211
44
35
16
18
11
3
3
4
2
3
3
3
2
1
2
1
1
2
Average
rounded
off
Grouped
207 207
50 1
31
18 .
15 ~
9
6
4
3,
3a
3a
2a
2
1
1
1
1
1
la
la
1
0
0
0
0
0
0
0,
4a,
81
> 77
aSmoothed out.
-
1 Ih-T-n-r-^— „ R
motnou)
r»ocvi
ooo.-J.-I
i i i i i
o«o <-ito.-<
emmr—o
ooo'f-4
o
o
o
o
o
o
§
J_
a>
INCHES PER DAY
Figure 14. Rainfall frequency distribution.
170
-------
Table 6. DRY ASH IN HARVESTED CANE3
Rainfall,
inches/day.
(corrected )
0.0-0.25
0.26-0.75
Over 0.75
Tons ash/Tons pol
Conventional
harvest
1.00
1.25
1.36
Harvester
- cleaner
0.55
1.00
1.41
Ash/jDOl
reduction
in percent
45.0
20.0
-3.7
Data based on period November 25-27, 1974.
'Corrected rainfall = % day before yesterday ~+ % of yesterday
+ h of today.
1.71
-------
This was found to be necessary because of the lag in harvesting
operations from the time the field is first opened up and V-cut to the
time the cane is loaded into the trucks. If this compensation for the
operating lag is not made the scatter-gram of data is undecipherable.
If the data shown in Table 6 are used to estimate reduction in
annual ash loadings the plot shown in Figure 15 results. Such
extrapolation is useful only to indicate order-of-magnitude effects
which in this case are shown to be total reduction of about 43,000 tons
dry ash per year, corresponding to about 59,000 tons dry soil or about
200,000 tons of soil at 70 percent moisture (normal moisture for soil in
the area). Aside from the costs of wastewater treatment itself, the
cost of hauling this excess material back and forth from field to
factory to field would approach $1,000,000.00 per year at 1974 trucking
costs.
Analysis of Economic Effects
In December, 1974, the environmental engineering firm of Sunn, Low,
Tom and Hara of Honolulu were asked to prepare an up-date of a prior
report on wastewater management alternatives and to indicate estimated
costs for several alternatives being considered by the Hilo Coast
Processing Company. The alternatives were these:
1. Construct a wastewater treatment plant to handle 1,400 tons dry
solids per day at ten million gallons per day hydraulic
loading. This alternative was, in effect, end-of-pipeline
treatment.
2. Construct a plant with 350 tons per day dry solids loading
capability at 5 million gallons per day hydraulic loading.
3. Construct temporary pre-treatment facilities to handle the peak
loads between 350 tons per day and 1,400 tons per day until the
CMH and cane cleaner programs are fully effective.
The preliminary construction cost estimate for these alternatives
are shown in Table 7 and some of the unit costs based on 1974
construction costs in Hawaii are shown in Table 8. These costs were for
the Pepeekeo factory only and similar, but lower, costs were developed
for the smaller plant at Papaikou.
The 350 tons dry solids per day level of plant size represents the
plant needed for a harvesting quality of 4 percent ash on net cane,
assuming that all cane trash from Papaikou is washed and burned at
Pepeekeo. About 100 tons per day excess capacity is built in to handle
peak loads.
172
-------
80-
70-
60-
o:
2
>-
S 50-
y
3
b_
O
to
I 40-
o
UJ
fe
UJ
a.
30 -
20-
10 -
PROJECTED ON 145,000 TONS POL/YR
DATA BASED ON PERIOD
25 NOV 74 to 27 DEC 74
Harvester .Conventional
Cleaner \ / Harvest
i
\ ;
* j
r
7
0-0.25 0.25-0.75 Over 0.75
INCHES PER DAY
Figure 15. Ash versus daily rainfall (corrected).
173
-------
Table 7. PRELIMINARY CONSTRUCTION COSTS
9
Unit Process
Hill Interface
1. Grit chamber
2. Pump station
3. Transmission lines
Subtotal
Pretreatment
4. Sedimentation
a. Pond construction
b. Slurry dewaterlng
c. Sol Ids disposal equipment
5. Pumping/recycling
a. Pump stations
b. Transmission lines
c. Odor and quality control
Subtotal
Treatment and Disposal
6. Treatment
a. Flocculators
b. Clarlfier
c. Thickener
d. Dewaterlng
e. Solids disposal equipment
f. Pump and control building
g. Exterior piping and electrical
h. Site work
7. Effluent disposal line
Subtotal
Solids Disposal Site
8. Site development
9. Roadways
Subtotal
GRAND TOTAL
Settling and
thickening ponds
$ 140,000
707,000
309.000
$ 1,156.000
$ 1,892,000
7,228,000
1,340,000
135,000 .
( )b
$10,595,000
$ 157,000
1,040,000
679,000
1,278,000
230,000
501,000
163,000
192,000
140,000
$ 4.380.000
'1 1
$( )
$16,131,000
Cascading
ponds
$ 140,000
1,061,000
1,431,000
$ 2.632,000
$ 5,850,000
7,228,000
1,960,000
1,414,000
480,000
$16,932,000
$ 157,000
1,040,000
679,000
1,278,000
230,000
501,000
163,000
192.000
140,000
$ 4,380,000
1 !
$( )
$23,944,000
Gulch ponds
$ 140,000
1,061,000
816,000
$ 2,017,000
$ 2,435.000
7.228,000
2.006,000
707,000
230,000
$11,630,000
$ 157,000
1.040,000
679,000
1,278,000
230,000
501,000
163,000
192,000
140.000
$ 4,380,000
'1 1
$( )
$19,003,000
Ditches
$ 140,000
1,061,000
1.853.000
$ 3,054,000
$ 4,217,000
7,228,000
2,960,000
707,000
281,000
$14,393,000
$ 157,000
1,040,000
679,000
1,278,000
230,000
501,000
163.000
192,000
140,000
$ 4,380,000
'I 1
$( )
$21,827.000
Full -size
treatment
$ 140,000
707,000
280,000
$ 1,127.000
255.000
$ 255,000
$ 157.000
4,407,000
2,794,000
5,112,000
966,000
1,542.000
423,000
317,000
25.000
$15,743,000
$i 1
$( )
$17,125,000
350 TPD plant
$ 146,000
707.000
140.000
$ 987,000
$ 157.000
1,040,000
679,000
1,278,000
230.000
501.000
163.000
192.000
140.000
$ 4,380,000
1 I
$( )
$ 5,367.000
aCosts are based on 1974 prices.
b( ) Indicates additional major cost Items are not defined
-------
Table 8. UNIT COSTS USED IN PRELIMINARY ESTIMATES
(September 1974)
1. Concrete
Makakilo STP
Hawaii Kal STP IV-A
Z. Structural Excavation
Makakilo STP
Hawaii Ka1 STP
3. Mass Excavation
Pearl Harbor Interchange (large quantity)
HECO (Waiau - small pond)
4. Embankment
5.
Pearl Harbor Interchange (large quantity)
HECO (Waiau - small pond)
Piping - In Place Complete (assume 1n soil with 5 feet cover)
Makaha Meadows - 6 Inch line
Ehukai Sewer - 24 and 30 inch lines
Use the following:
Pipe size (inches)
Cost/If (dollars)
8
27
10
30
12
35
16
45
20
55
24
70
30
90
6.
7.
8.
9.
10.
11.
Dam (end dump of boulders)
Reef Runway - $16.00/ton x 1.4 tn/cy «
Filter Material (in place complete)
Naw1l1w1H Boat Harbor
Roadway
Excavation - MakakiTo Mala Access Road
Crushed Rock - Makakilo Mala Access Road
Wooden Curbing - Makakilo Mala Access Road
Sludge Collecter (rectangular)
Makakilo STP - 18' wide x 40' Ig tank
Hawaii Kai STP - 16' wide x 100' Ig tank
Hawaii Kai STP - 20' wide x 86' Ig tank
Sludge Collector (circulat)
Schofleld STP - 55' primary
Schofield STP - 60' secondary
Plug Valves
Pipe size (Inches) 6 8
Material cost 210 310
Installation cost 190 190
CosVlf (dollars) 400 500
10 20 24
610 2.600 5.200
390 1,400 1,800
1,000 4,000 7,000
$450-$760/cy
$370-$460/cy
$30-$70/cy
$130$25/cy—soil w/mud rock
$2.24-$5.10/cy—rock
$4.00/cy—soil and coral
$2.50-$3.50/cy—rock
$4.00/cy—soil and coral
$23.00/lf
$80.00/lf
$22.40/cy
$0.65-$0.90
$3.80-$12.50/cy
$2.85-$3.00/sy
$3.70-$4.00/lf (concrete)
$42,000
$60,000
$60,000
$36,000
$44,000
Use $500.00/cy
Use $20.00/cy
Use $3.00/cy
Use $3.00/cy
Use $23.00/cy
Use $1.00/sf
Use $7.00/cy
Use $3.00/sy
Use $3.00/1f
Interpolate
in different
sizes
175
-------
The quality requirements for the suspended solids removal by the
wastewater treatment plant were in the range of 93 percent to 96
percent, depending upon load, and were based on NPDES permit
requirements. It was obvious, once again, that end-of-pipeline
treatment was financially impossible and that the CMH quality standard
of 4 percent ash entrainment had to be met.
The Cane Materials Handling System, the success of which is
fundamental to the success of the total water pollution abatement
program also has certain capital investment, leasing and operating costs
involved. The CMH portion of the program has required a commitment of
$6,483,000 for the period 1974 to 1977.
The projected capital and operating costs of the wastewater
treatment facility at the Pepeekeo factory through 1978 are as follows:
1975 1976 1977 1978
Capital Cost
350 tons per day $450,000 $4,971,000 $ - $ -
(1974 dollars,
unescalated)
Operating Costs
(Escalation) 10% 14% 10% 10%
Services - - 623,800 686,200
Payroll - - 491,900 541,100
Material - - 392,000 431,600
Fixed Charges - 110,900 801,800 801,800
TOTAL - $110,900 $2,309,900 $2,460,700
The cost estimates are based on the 350 tons dry solids per day
plant capacity which is judged to be adequate under all conditions if
the elements of the abatement system operate as shown in Table 9, Column
E. Table 9, based on the most recent and most pessimistic data
available, indicates that the system will achieve the required levels of
abatement if all elements of the system operate as predicted. The
maximum level of entrained soil shown in Column B, Table 9, at the 100
percent level, is that amount which occurs in very wet weather using
conventional harvesting methods. These methods are being phased out as
CMH equipment becomes available and thus the predicted maximum load to
be handled at the factory shifts downward in Columns E and F, Table 9,
to the bottom of the first vertical arrows in these columns.
176
-------
Table 9. WET CONDITIONS, EXPECTED SOIL LOAD TO WATER
TREATMENT FACILITIES
1,800 - -
1,600--
1,400
1,200 - -
1,000--
i
o:
I
E.
£. 600
i
£ 400 - -
CO
o
n
U
0-
*HP
0 -
0-
0 -
0 -
0 -
0-
n
120
110
B
100
90
"Q80
-1
- o
"leo
t«*4 v**
13
~ 0£
O
-g50
' ~
£40
- LU
UJ
- 0.
30
20
10
!•«
n
" 112.5%
1,800 tpd
-Dry Fiber
fm Trash3
-
-
-
-
~
-'
HOT '
1,600 tpd
f
i
Dry Dry
Cleaning Cleaning
(0.4 of (0.4 of
original original
load load
removed) removed)
« i •
60%
960 tpd
p
Screening
(0.4)b
J
[
36%
576 tpd
A B C D
70«
Dbl
>
CMH
.Pass,
30% Conv.
w/F1eld
Cleaning
(0.4 of
original
load
removed)
«
t
t
•
.
«
70% CMH
Sgl.Pass/
30% Conv.-
w/Field -
Cleaning
(0.4 of -
original
load
removed)
Dry
Cleaning
(0
J
1
.4)"
1
* i
Dry
Cleaning *
K
(0.4)b
Screening |
(0
.4)b
1
21
.6%
346 tpd
E
* -
Screening
(o.4)b :
^
15.5* -
248 tpd •
F
Tons Dry Soil
from Field
Net Tons Cane
Ratio
1,600
5,050
.317
1,600
5,050
.317
1,600
5,050
.317
1,600
5,050
.317
960
5,050
.190
688
5,050
.136
Estimate of Tons Dry Fiber from Trash: 5,050 Net Tons Cane/Day + 110 Tons Cane/Acre =
45.9 Acres/Day. 45.9 Acres/Day x 5.6 Tons Dry Fiber/Acre x 778 •= 200 Tons Dry Fiber/Day.
Of remaining Soil Load removed.
177
-------
The required efficiency of the water treatment system under the
different loading conditions shown in Table 9 is illustrated in Table 10
for the limits set under existing NPDES permits. The limits are set, as
can be seen, in such a way that the annual efficiency required for
suspended solids (soil) removal is 92 percent to 94 percent with a fully
implemented CMH program and up to 98 percent with conventional
harvesting but with trash hauled away (not washed) and with cane cleaner
wash water screened through fine mesh static screens. This chart (Table
10) once again emphasizes that end-of-pipeline treatment is impractical
in that it is very doubtful that 98 percent efficiency could be achieved
as an annual average on a continuous 46-week annual operation.
CONCLUSIONS
An over-view of experience to date with the elements of the
wastewater pollution abatement program would indicate that the most
probable alternatives to be followed in the future are these:
1. Field areas now inaccessible to the CMH machines (approximately
30 percent of the total area in cane) will be moved to
roadsides by conventional methods and will then be picked up by
the pick-up cleaner harvester and delivered directly into
trucks, thus performing a field-cleaning operation on the cane
before hauling in order to reduce soil pick-up.
2. Leafy cane trash will be handled two ways in wet weather.
a. Pick-up cleaner harvester blowers will be used.
b. Dry cane cleaner trash will be hauled away for land
reclamation.
3. Third generation pick-up cleaner harvesters will be single-pass
machines with dual cutting heads and a laterally adjustable
cutting and pick-up assembly which will permit offset cutting
to avoid crushing uncut cane.
4. Wastewater management will include every feasible method for
reducing both solids loading and hydraulic loading to the
treatment plant.
It is also probable that more new CMH equipment will come into use
in the harvest field than is now foreseen as the shift in emphasis
toward better quality of harvested cane becomes increasingly evident.
178
-------
Table 10. WET CONDITIONS, PERCENT SOIL REMOVAL BY WATER TREATMENT
FACILITY REQUIRED TO MEET NPDES PERMIT LIMITS
o
in
i
UJ
in
960a l'^Ll
•IH
«••
^PM
500 -
A
A 1 1
^i-e ~
+ ~
t*Hi
0 _
~9l
)%
1
83%
^
9
T
•tcae
76
T
71%
T
59%
—
B.
7%
T
96%
T
f\fal
9f
« T
93%
•
9
T
9
0%
«•
•••
«•
8%
T
97%
T
f\faJ
95% f
94%
T
92% ~
Daily Pollutant
Discharge Rate
101 Tons/Day
30-Day Average
Daily Pollutant
Discharge Rate
25.7 Tons/Day
Annual Average
Daily Pollutant
Discharge Rate
18.8 Tons/Day
NPDES PERMIT LIMITATIONS
Allowable Pollutant Discharge to Ocean
a960 tpd. Conv. Harv., all trash recovered, soil load reduced by 0.4 with screening.
b576 tpd. Conv. Harv., no trash recovered, soil load reduced by 0.4 with dry cleaning, and
remaining load reduced by 0.4 with screening.
C576 tpd. 70% CMH double pass harv., 30% Conv. Harv., with field cleaning, all trash
recovered, soil load reduced by 0.4 with screening.
d413 tpd. 70% CMH single pass harv., 30% Conv. Harv., with field cleaning, all trash
recovered, aoil load reduced by 0.4 with screening.
*346 tpd. 70% CMH double pass harv., 30% Conv. Harv. with field cleaning, no trash
recovered, soil load reduced by 0.4 with dry cleaning and remaining load reduced by 0.4
with screening.
*248 tpd. 70% CMH single pass harv., 30% Conv. Harv. with field cleaning, no trash
recovered, soil load reduced by 0.4 with dry cleaning, and remaining load reduced by 0.4
with screening.
179
-------
UTILIZATION OF CHEESE WHEY FOR WINE PRODUCTION*
Hoya Y. Yang**
Floyd W. Bodyfelt**
Kaye E. Berggren**
Peter K. Larson**
INTRODUCTION
Effective and economical methods of utilizing whey are essential if
cheese plants are to remain competitive with other segments of the food
processing industry. The drying of cheese whey is limited by some
adverse economic considerations. An efficient whey drying operation
requires more whey than most cheese plants produce. Also, large volumes
of water would have to be removed, thus requiring considerable
consumptions of our diminishing energy resources.1
Utilization of whey for wine production requires little or no
energy resources. The entire whey is utilized; no removal of water is
necessary. Furthermore, whey can be utilized by small cheese plants for
wine production, since no elaborate or expensive equipment is required.
Acceptable wine also has a higher monetary value than other
products. From 100 pounds of milk, 10 pounds of cheese is produced; the
remaining 90 pounds is whey. Ten pounds of cheese can be retailed for
approximately $15; 90 pounds of whey can be made into 10 gallons of whey
wine and be retailed for about $50, assuming $1 per fifth bottle. The
economic advantage of utilizing whey for wine production is obvious.
*This investigation was supported by funds from the US Environmental
Protection Agency, under Grant Number R803301. This progress report
covers 'the first half, from July 1, 1974 to February 28, 1975, of the
16-month grant period.
**Department of Food Science and Technology, Oregon State University,
Corvallis, Oregon 97331.
180
-------
The use of whey as a fermentation substrate has appealed to micro-
biologists, food scientists, cheese processors, and others who have been
faced with the problem of upgrading this raw material into useful
products which can be produced and marketed on a profitable basis. Whey
has been used or suggested as a substrate for the manufacture of yeast,
alcohols, lactic acid, vitamins, vinegar, and alcoholic beverages. The
production of wine or other popular alcoholic beverages from whey has
remained a laboratory curiosity for many years.5 r
As early as 1868, a US patent was granted to Baldwin3 for the
production of a cordial from whey. In 1948 and 1952, EngeT1'5 was
issued several patents for the production of an alcoholic beverage, in
which sucrose and whey were fermented with baker's yeast. A variety of
beer-like products have also been produced from whey in Germany.6
The US cheese industry is in most urgent need of a development of a
whey by-product that would not encompass relatively expensive processes
for water removal. The fermentation of sugar fortified whey by selected
wine yeast and the production of an acceptable whey wine may represent a
"near ideal" solution for the whey disposal and utilization dilemma of
the US cheese industry. The production of an acceptable wine by whey
fermentation may be the means of transposing a "cost of doing business"
into a "profit opportunity". These, then, are the objectives of this
project that would hopefully be carried to reality.
METHODS
Whey for this project was obtained from cheese plants located in
Oregon and Washington. Thus far, cheddar cheese whey has been used for
the experiments.
The general scheme of wine production from whey is shown in Figure
1. For making clear whey wine, it is necessary to de-proteinize the
whey. This is done by heating the whey to 180 degrees F for five
minutes. The protein thus precipitated is removed and could be utilized
as food ingredients. About 22 percent of dextrose is added to the clear
whey, depending on the concentration of alcohol desired in the wine.
After cooling, 100 parts per million of sulfur dioxide is added for
stability. The whey is then inoculated with yeast. Fermentation
commences shortly thereafter. When fermentation is completed and yeast
cells are settled, the wine is racked. This procedure is repeated once
or twice. The lees are a good source of protein and could be used in
foods or animal feeds. The wine is then aged and clarified by a fining
agent. It is sweetened, if a sweet wine is desired. To insure clarity,
181
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WHEY
DE-PROTEINIZATION
DEXTROSE ADDITION
I
S00 ADDITION
2 I
INOCULATION
I
FERMENTATION
I
FIRST RACKING
SECOND RACKING
I
FINING
I
"""SWEETENING
I
FILTRATION
BOTTLING
MILK PROTEIN
UTILIZATION
YEAST PROTEIN
UTILIZATION
***
••'PASTEURIZATION
Omitted if a cloudy wine is produced
Omitted when a dry wine is produced
Omitted if an aseptic method is used
Figure 1. Production of sweetened clear whey wine.
182
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the wine is filtered before bottling. Sweet wine should be pasteurized,
or handled aseptically, to prevent secondary fermentation.
RESULTS AND DISCUSSION
Yeast
Table 1 shows the effect of different wine yeast strains on the
fermentation rate of whey wine. Of the five yeasts tested, Montrachet
fermented the fastest, taking an average of seven days to ferment whey
to wine at room temperature. Champagne and Sherry were only slightly
slower, taking eight days. Port took 12 days, and Burgundy 14 days.
All yeasts produced the same alcohol content at the end of the
fermentation, above 10 percent by volume. Sensory evaluation conducted
thus far reveal no conclusive difference in flavor between wines
fermented by different yeast strains. It appears that Montrachet is the
preferred yeast for whey wine fermentation due to the more rapid rate of
fermentation.
Temperature
Three fermentation temperatures were tested for their effect on the
rate of fermentation and flavor of wine. Results are shown in Table 2.
At the incubator temperature of 90 degrees F, it took an average of only
four days for Montrachet yeast to ferment whey to wine; at room
temperature, it took seven days. In a refrigerated room at 55 degrees
F, fermentation was the slowest; 17 days were required for completion.
The slightly lower alcohol content of the wine fermented at 90 degrees F
could be due to the volatile nature of alcohol at higher temperatures.
Sensory evaluation revealed no significant difference between the
wine fermented at 55 degrees and that at 72 degrees F. The wine
fermented at 90 degrees F, however, was definitely disliked by the
panelists. This could be due to the rapid deterioration of the whey at
that temperature. In the interest of energy conservation, fermenting
whey wine at room temperature appears to be the most desirable.
Nutrients
Nitrogen as a yeast nutrient was supplied by a mixture of 50
percent ammonium phosphate and 50 percent ammonium chloride. This
mixture was tested at concentrations of 500 and 1,000 parts per million.
183
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Table 1. EFFECT OF YEAST STRAINS ON FERMENTATION RATE
Yeast
strain
Montrachet
Champagne
Sherry
Port
Burgundy
Time for completion
of fermentation,
days
7
8
8
12
14
Fermentation
rate,
days"1
0.14
0.13
0.13
0.08
0.07
Alcohol
production,
%
10.35
10.25
10.00
10.20
10.10
Table 2. EFFECT OF TEMPERATURE ON FERMENTATION RATE
Temperature,
°F
55
72
90 ,
Time for completion
of fermentation,
days
17
7
4
Fermentation
rate,
days"1
0.06
0.14
0.25
Alcohol
production,
%
10.65
10.51
10.20
184
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Vitamins Bi (thiamin) and 62 (riboflavin), known also to increase the
efficiency of yeast fermentation, were tested at 5 parts per million,
respectively. The results in Table 3 show that the addition of yeast
nutrients was not found to be necessary for fermentation of whey wine.
Neither the fermentation rate, nor the percentage of alcohol produced
was increased significantly. It appears that the whey itself contains
sufficient nutrients for yeast growth, and additional nutrients are of
no value.
Preservatives
Sulfur dioxide and sorbic acid were tested as preservatives for
whey wine. The effectiveness of the preservatives was determined by
plate counts of viable microorganisms at different time intervals.
Results are shown in Table 4. After nine weeks, some samples had coents
of a few hundred microorganisms per nrilliliter. These are considered as
low counts for wine. All the wine samples had a decrease in counts at
subsequent intervals. At the end of 19 weeks, all samples are virtually
sterile, including the control. Evidently, the combined preservation
effect of alcohol and lactic acid present in the wine offers sufficient
protection for dry whey wine, and no chemical preservatives are needed.
Wine treated with 100 parts per million SO2, however, seems to have a
cleaner taste and perhaps would be a desirable practice. Sorbic acid
treated wines exerted some effect on the flavor of the wine. The degree
of off-flavor was in proportion to the preservative concentration.
Clarifying Agents
To make clear whey wine, bentonite has shown promise as a
clarifying agent as shown in Table 5. This clarifying agent, when used
in a concentration of 0.5 percent, showed excellent results for
clarifying cloudy whey wine. It was observed that de-proteinized whey
produced cloudy whey wine, due to the activity of the yeast.
Sparkolloid (a trade name for a polysaccharide product) and casein
were found to be poor clarifying agents for whey wine. Adjusting the pH
of the wine with potassium carbonate to the iso-electric point of whey
protein (pH 5.1 to 5.3) facilitated protein precipitation. The problem
here, however, is that at the iso-electric point, the wine is low in
acidity, and tastes flat.
Tannin appears to be a good clarifying agent, except that it may
impart an off-flavor to the wine. Its use is presently undergoing
further study.
185
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Table 3. EFFECT OF NUTRIENTS ON FERMENTATION RATE
Nutrient
Control
250 ppm (NHit)2HPOi,
+ 250 ppm NH^Cl
500 ppm (NHi,)2HPOu
+ 500 ppm NHi.Cl
5 ppm Vitamin BI
5 ppm Vitamin B2
Time for completion
of fermentation,
days
7
8
7
8
8
-Fermentation
rate,
days"1
0.14
0.13
0.14
0.13
0.13
Alcohol
production,
10.3
10.2
10.1
10.1
10.3
Table 4. EFFECT OF PRESERVATIVES ON VIABLE MICROORGANISMS
IN WHEY WINE
Plate counts (colonies/ml) after;
Preservative
Control
S02, 50 ppm
S02, 100 ppm
S02, 200 ppm
S02, 300 ppm
Sorbic acid, 100 ppm
Sorbic acid, 200 ppm
Sorbic acid, 300 ppm
Sorbic acid, 400 ppm
9 weeks
800
1,300
8
0
0
400
18
30
0
12 weeks
110
58
1
0
1
135
0
167
0
15 weeks
4
9
1
0
0
1
1
9
-
19 weeks
0
3
0
0
0
1
2
0
-
186
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Table 5. EFFECTIVENESS OF CLARIFYING AGENTS FOR WHEY WINE
Clarifying agent, %
Bentonite
0.20
0.25
0.30
0.50
Sparkolloid, cold
0.01-0.20
Casein
0.01-0.20
Tannin
0.010
0.015
0.020
K2C03
0.44
0.48
0.52
Clarif
Poor
X
X
X
X
Fair
X
X
/ing action
Good
X
X
X
X
Excellent
X
X
187
-------
Cloudy and clear whey wines were compared by gas-liquid
chromatography. The instrument used was a Varian Aerograph 1200 with a
hydrogen flame ionization detector. Samples of whey wines were injected
directly.
The column used was a 12 foot by 1/8 inch stainless steel packed
with 5 percent BDS (butanedial succinate) and 0.05 percent igepal on
Chromosorb G. The column was conditioned at 170 degrees C and
maintained at 135 degrees C. The range was set on 1 and the attenuation
was 128. The nitrogen flow was 20 milliliters per minute, the sample
size was 10 micro!iters, and the chart speed 20 inches per hour.
Typical gas chromatographs are reproduced in Figure 2. It is seen
that both the cloudy and the clear whey wines produced identical
chromatograms, indicating that the volatile components present in the
whey wine were retained after clarification. Peak 2 of the clear wine,
however, is lower than that of the cloudy wines, indicating that perhaps
some loss of this component may have occurred during fining and
filtering.
No attempt has been made at this point to identify the chemical
compounds represented by the peaks on the chromatograms. It is
anticipated that this will be done in the future, in conjunction with
the investigation of the smaller peaks and their significance in the
total flavor of the whey wine.
Fruit-Whey Wines
The possibility of blending fruit and berry wines with whey wine
was investigated. Raspberry, strawberry, blackberry, apple, and pear
wines were prepared according to methods prevailing in the Pacific
Northwest.7 Each fruit or berry wine was blended with whey wine on a
50-50 basis. All the berry blends of whey wine were considered
acceptable in the flavor preference tests that were conducted (Table 6).
The apple and pear blends were not considered acceptable. This is
probably because these two fruits are generally weaker in flavor, as
compared to the berries.
Flavored Whey Wines
The possibility of flavoring whey wine with synthetic flavors was
investigated. Citrus, cola, and raspberry flavors were evaluated. The
cola-flavored wine left a medicinal after-taste, and was not acceptable.
A 50-50 blend of whey wine and Coca-Cola, however, was a more acceptable
product. The raspberry-flavored whey wine was not comparable to the
188
-------
8
2
to
a
ex
CO
CLOUDY WINE
CLEAR WINE
•
(m)
10
TIM (mi)
Figure 2. Gas chromatograms of whey wine.
10
-------
natural raspberry-whey wine blend previously tested. The flavored
raspberry wine tasted "synthetic", without the aroma of true raspberry.
The citrus-flavored whey wine was considered the best product of the
three flavored wines tested. The product has a pleasing taste, which
resembles some citrus-flavored pop wines currently selling on the
market.
Carbonation
Carbonation was attempted on the flavored whey wines. When a wine
was carbonated to a pressure of 2.3 volumes of C(h, it had a nice head
when poured, with bubbles in the glass. Testing of a commercial beer
and Coke for pressure gave 2.3 volumes of C(h for beer and 3.3 for Coke.
Acceptance
Whey wine, fruit and berry blends, and citrus-flavored wine were
submitted for sensory evaluation by Oregon State University personnel,
the dairy industry, and other groups. A hedonic scale of 1 to 9 was
used for scoring. A score of 5 implies the sample is neither desirable
nor undesirable. A mean score of 5 generally indicates the sample is
desirable. The higher the score, the higher the desirability. Any
score below 5 is rated undesirable.
Table 6 shows the results of the sensory evaluation tests
conducted. It is seen that, with the exception of clear dry whey wine
and the apple and pear blends, all wines were rated with a relatively
high degree of preference by the panelists. The raspberry-whey blend
received the highest rating of 6.9. Clear dry whey wine was rated the
lowest, 3.8, with apple and pear blends rated just below the neutral
point of 5.
One special wine tasting was conducted with a large group during
the 1975 Oregon Dairy Industries Conference. A sweetened clear whey
wine and a sweetened raspberry-whey wine were submitted to the group of
over 300 people for tasting. One hundred and seventy-seven persons
completed ballots. The results are summarized in Table 7. It is noted
that the majority of the participants liked the clear whey wine or the
raspberry wine blend. Only 7 out of the 177, or approximately 4 percent
of those tasting, disliked both samples.
It should be noted that the wine samples were evaluated by a
different number of varied groups of people in some cases. While the
results may serve as an indication of the relative degrees of preference
190
-------
Table 6. RESULTS OF SENSORY EVALUATION TESTS FOR VARIOUS WHEY WINES
Wine type
Whey, cloudy, sweetened
Whey, clear, dry
Whey, clear, sweetened
Raspberry-whey, sweetened
Strawberry-whey, sweetened
Blackberry-whey, sweetened
Apple-whey, sweetened
Pear-whey, sweetened
Whey, citrus-flavored,
sweetened
Number of panelists
109
36
145
126
25
25
25
25
50
Mean score
5.2
3.8
6.3
6.9
6.4
6.4
4.6
4.7
5.5
Table 7. FLAVOR PREFERENCE EVALUATION BY OREGON DAIRY INDUSTRY GROUP
Flavor evaluation statement
"I like the raspberry-whey wine"
"I like the clear whey wine"
"I like neither"
Ballot count
123
47
7
Preference, %
69.5
26.6
3.9
191
-------
for the products, large scale consumer acceptance tests of each product
must be conducted.
EXPERIMENTS IN PROGRESS
Experiments now in progress include the possibility of developing a
whey beer, stability tests of wine under various storage conditions,
packaging of whey wine, and production of wine from acid (cottage
cheese) whey.
SUMMARY
Among the wine yeast strains tested, Montrachet was found to be the
most desirable for whey wine fermentation. With this yeast,
fermentation can be carried out at room temperature satisfactorily.
Yeast nutrients, such as nitrogen and B-vitamins, show little help in
increasing the rate of fermentation. It appears that the whey itself
contains sufficient nutrients for yeast growth, and additional nutrients
are of little or no value.
Chemical preservatives, such as sulfur dioxide and sorbic acid, are
not needed for dry whey wine. Evidently, the combined preserving effect
of alcohol and lactic acid present in the wine offers sufficient
protection. Wine treated with 100 parts per million S02, however, seems
to have a cleaner taste, and perhaps would be a desirable practice.
To make clear whey wine, bentonite has shown promise as a
clarifying agent. Cloudy and clear whey wines were compared by gas-
liquid chromatography, and both wines produced identical chromatograms,
indicating that the volatile flavor components present in the whey wine
were retained after clarification.
Whey wine was also blended with fruit and berry wines to produce
fruit-whey wines. It was also flavored with synthetic flavors and
carbonated to produce effervescent, flavored, whey wine.
Flavor preference test results show that a great majority of the
panelists liked, in various degrees, one or more of the whey wine
preparations. The favorites of the panelists were clear sweetened whey
wine and whey wine blended with berry wines, especially raspberry-whey
wine.
192
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REFERENCES
1. Bodyfelt, F. W. Whey Disposal in the Pacific Northwest.
Proceedings of the Pacific Northwest Industrial Waste Management
Conference. 39:27. 1972.
2. Holsinger, V. H, L. P. Posati, and E. D. Devilbiss. Whey
Beverages: A Review. J. Dairy Science. 57:849. 1974.
3. Baldwin, A. E. Improved Process of Treating Milk to Obtain Useful
Products. US Patent 78,640. 1868.
4. Engel, E. R. Fermenting Whey. US Patent 2,449,064. 1948.
5. Engel, E. R. Improvements In or Relating to a Process of Producing
an Alcoholic Beverage and a Solid Residuum from Whey. British
Patent 669,894. 1952.
6. Wix, P. and M. Woodbine. The Disposal and Utilization of Whey,
Part II. Dairy Sci. Abstr. 20:622. 1958.
7. Yang, H. Y. Fruit Wines—Requisites for Successful Fermentation.
Agri. and Food Chem. 1:331. 1953.
193
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DRY PEELING OF TOMATOES AND PEACHES
Traver J. Smith*
INTRODUCTION
For many years Magnuson Engineers has been developing and manu-
facturing machinery for peeling fruits and vegetables for the canning,
freezing and dehydration industry. In recent years, this effort has
been directed toward dry peeling because of the demand to reduce the
water pollution which has traditionally been associated with fruit and
vegetable peeling. A particular effort has been made to provide
equipment which is self-amortizing through savings in labor, increased
yield, and reduced waste water treatment costs.
DRY PEELING SOFT FRUITS AND VEGETABLES
Included in this effort has been the development of the soft fruit
MAGNUSCRUBBER unit which is designed to gently remove the peel from soft
fruits and vegetables without use of water and to collect the peel waste
residue and keep it out of the processing plant waste water effluent.
This is done by collection, haulage, and separate disposal of
concentrated peeling wastes. The principal application of these
machines has been for peeling tomatoes and peaches. During the just
completed 1974 season, many of these machines were operating in
production operations throughout the United States. Some machines have
completed three seasons of operation. The soft fruit MAGNUSCRUBBER unit
has also been used successfully for peeling apricots, pears, and cooked
beets.
*Vice President, Magnuson Engineers, Inc., San Jose, California,
194
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Equipment Description
To gently wipe away softened peel, the machine uses very thin soft
rubber discs developed by Mr. Robert Graham of the Western Regional
Research Center in Albany, California.1 In Mr. Graham's original
machine, he placed these discs on rotating cylindrical rolls arranged
side-by-side to form a flat bed. The product moved across the bed from
roll to roll in a direction perpendicular to the roll axis and parallel
to the disc surfaces. It utilized a displacement type feed. That is,
incoming produce displaced the product already on the bed and caused it
to move across the rolls. This machine was first demonstrated in 1970
on apricots and peaches.
Initial Test
During the following processing season, 1971, Magnuson Engineers
modified a standard MAGNUSCRUBBER machine of the type which was then
already widely in use for peeling root vegetables, by installing the
Graham soft rubber discs. In this machine and in subsequent production
machines, the rotating rubber disc rolls are assembled in a circular
revolving cage containg a feed screen through the center. The product
flow is at right angles to the Graham unit. In this machine the fruit
moves parallel to the roll axis and perpendicular to the surfaces of the
roll discs. This gives more complete envelopment of the product within
the soft moving disc surfaces, providing gentle, thorough scrubbing much
like wiping the fruit with the palms of the hands. The feed rate is
accurately controlled by the central screw conveyor.
For a high volume production machine, the disc roll arrangement of
the MAGNUSCRUBBER has proved to provide much more effective and
controllable peel removal than can be obtained with the flat bed type
unit.
PEACH PEELING
With minor exception, peaches are always pitted as the first step
in the processing operation. All pitting machines cut the fruit in half
while removing the pit. Consequently, the peeling process must be
applied to pitted peach halves. These are mechanically placed on a
conveyor in a "cup down" position (peel upwards) and a hot caustic
solution of 1 to 3 percent sodium hydroxide is cascaded over them,
exposing only the upper skin surface to the caustic action. Later, on
the same conveyor, they are sprayed with jets of water to flush away the
caustically disintegrated peel as finely dispersed particles. This
195
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process, of course, produced large volumes of waste water containing
caustic combined with peach solids, both suspended and dissolved.
In 1971, this first experiment disc roll type MAGNUSCRUBBER unit
was demonstrated for peeling clingstone peach halves.2 The product was
peeled with thorough skin removal, the corner of the half at the cut
surface remained sharp and peach halves had high quality appearance.
The machine was run at capacities above 20 tons per hour and the
demonstration was considered successful. The same season, a machine of
the flat bed type was also tested and reported by the US Environmental
Protection Agency.3
Because these machines were run in test situations where they were
carrying only a portion of the plant production, they were necessarily
operated side-by-side with conventional water spray peeling. It was,
therefore, necessary to provide sufficient caustic treatment of the
fruit to assure that the fruit processed in the spray washers would be
completely peeled. Since the rubber disc peeling process is more
vigorous in its action, the peaches peeled by this method experienced a
2 percent higher peel loss. This report of higher peel losses quickly
circulated through the peach processing industry and caused the
processors to be very apprehensive because of the added cost of these
higher losses. It has since been demonstrated with the MAGNUSCRUBBER
machine that it is only necessary to reduce the caustic treatment of the
peach halves to obtain very high quality peeling with equal or less peel
losses that are obtained by the conventional water spray method. In
addition, there is reduced caustic consumption which provides lower
operating costs.
Interestingly, the more effective scrubbing action provided by the
MAGNUSCRUBBER machine produces a labor saving in processing freestone
peaches. Freestones are fragile and subject to bruising in growth and
handling. These bruises leave surface defects which are visible after
peeling and hand labor is required to remove them. The wiping action of
the rubber discs removes many of these defects and thus reduces the hand
labor. As a result, several machines have been installed for peeling
freestone peaches, giving the double advantage of reduced labor cost and
reduced waste water treatment cost.
TOMATO PEELING
Immediately following the 1971 demonstration on cling peaches, the
disc equipped MAGNUSCRUBBER unit was moved to a tomato processing plant
which was operating after the close of the peach season. There it was
196
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established that the machine would also very effectively peel
caustically treated tomatoes.
Tomatoes peel very differently than peaches. Much stronger caustic
solutions are required (16 to 20 percent) and caustic-compatible wetting
agents must be used. While the tomato surface beneath the skin is
attacked by the caustic, the skin itself remains intact and comes off in
sheets of tissue. Other types of tomato peelers have difficulty in
thoroughly removing this peel tissue which tends to transfer from tomato
to tomato or from tomato to equipment and back to another tomato. Water
sprays are generally used to try to flush away these skins and hand
labor is required to finish the skin removal.
In the evolution of the MAGNUSCRUBBER machine for tomatoes, it has
been possible to remove substantially 100 percent of the peel at
capacities of 8 to 10 tons per hour without using any wash water at all.
This has eliminated nearly all the hand labor required to remove peel.
About one gallon per minite of lubrication water is used in the machine.
BOD REDUCTION
In both the tomato and peach peeling application, the MAGNUSCRUBBER
unit collects and delivers a full strength essentially undiluted peel
waste sludge. Since in these operations peel waste is a principal
source of biological oxygen demand (BOD) in waste waste treatment, it is
highly desirable to keep this peel waste material out of the plant waste
water. A 1974 study* indicates that peel wastes accounted for 60
percent of the total plant BOD load in a peach cannery and 35 percent of
the total BOD load in a tomato cannery. The plants studied were
generally typical of California processing methods. Food processors now
recognize that it is very expensive to remove a BOD load from waste
water, both in terms of the plant investment for waste water treatment
facilities and its operating cost. It is now widely acknowledged that
it is much better to prevent these wastes from entering the plant
effluent and thus avoid the cost of waste water treatment. This is
especially true in seasonal operations where expensive waste water
treatment facilities will be used for only two or three months per year.
INCREASED PRODUCT RECOVERY
During the 1974 season, a California processor who was using four
MAGNUSCRUBBER machines for dry peeling of tomatoes reported an increased
product removery of 2-1/2 cases per ton which was attributed entirely to
197
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the reduced product losses made possible by the MAGNUSCRUBBER units.
This plant also showed a 44.7 percent reduction in caustic consumption.
Such savings are possible because the mechanical wiping action of rubber
discs permits less caustic exposure of the tomatoes which reduces the
product losses in the caustic solution. Similarly, since water washing
is not used during peel removal, this eliminates the loss of tomato
solids which are normally carried away by the waste water.
PRODUCTION PROCESSING RESULTS
To make an accurate comparison between water wash peel removal and
dry peel removal, a detailed study was made in three canneries during
the 1974 peach and tomato processing seasons. The study was made by
CH2M-Hill and the data in the following tables has been extracted from
their report.**
CONCLUSION
From the tables presented, it is very apparent that the
MAGNUSCRUBBER machine provides very substantial reductions in water
usage, BOD, COD, and suspended solids in both peach and tomato canning
operations. These reductions are increasingly necessary in these
processes to meet demands for reduced water pollution.
Now that the mechanics of dry caustic peel removal are proven and
in production, much attention is focused on the handling and disposal of
peel waste sludge. So far, this material has been hauled from the plant
site in tank trucks and disposed of by spreading on land; sometimes on
pasture land where cattle are feeding. In one circumstance, where a
plant had traditionally been discharging peeling wastes into a river
until prohibited, the peel sludge was hauled 35 miles and dumped into a
city sewer, paying sewage charges. Obviously, better solutions
that are required.
So far, spreading on land is the only acceptable method for
disposal of peach peel waste. As this material becomes available in
greater quantities, probable uses for it will be found. Brandy
manufacture is a possibility.
Tomato peel waste offers a real promise as a by-product. The peel
waste material has a higher solids content than pureed whole tomatoes,
because it is made up entirely of material from the outer cells walls of
the tomatoes. This is the most highly colored portion of the tomato, so
198
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Table 1. PROPERTIES OF PEEL WASTE SLUDGE AS PRODUCED BY MAGNUSCRUBBER
Property
Peach peel waste
Tomato peel waste
Solids content, %
Weight, Ibs/gal.
pH
Color
Texture
9-10
8.5
13-14
Dark brown
Like pureed apple
sauce. Flows
sluggishly.
7-8
8.5
13-14
Bright red
Like tomato
puree with many
skins. Flows
easily.
Table 2. CAUSTIC PEELING OF PEACHES. REDUCTION OF PEELING WASTES
WITH MAGNUSCRUBBER
Parameter
Water flow
Biological Oxygen
Demand
Chemical Oxygen
Demand
Suspended solids
Peel removal method
per 1,000 Ibs of canned peaches
Spray washer
694 gals.
8.6 Ibs
12.6 Ibs
2.3 Ibs
MAGNUSCRUBBER
13 gals.
0.3 Ibs
0.9 Ibs
0.2 Ibs
Reduction
with
MAGNUSCRUBBER
98%
97%
93%
91%
199
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Table 3. CAUSTIC PEELING OF TOMATOES. REDUCTION OF PEELING WASTES
WITH MAGNUSCRUBBER
Parameter
Water flow
Biological Oxygen
Demand
Chemical Oxygen
Demand
Suspended solids
Peel remova
method
per 1,000 Ibs of canned tomatoes
Water Washing
604 gals.
6.0 Ibs
10.2 Ibs
2.2 Ibs
MAGNUSCRUBBER
14.5 gals.
2.4 Ibs
f
3.1 Ibs
0.5 Ibs
Reduction
with
MAGNUSCRUBBER
98%
60%
70%
77%
Table 4. PEACH CANNING. REDUCTION OF TOTAL PLANT WASTES
WITH MAGNUSCRUBBER
For total plant
Water flow
Biological Oxygen
Demand
Chemical Oxygen
Demand
Suspended solids
Peel removal method
per 1,000 Ibs of canned peaches
Spray washer
1,470 gals.
13.6 Ibs
25.2 Ibs
6.5 Ibs
MAGNUSCRUBBER
789 gals.
5.3 Ibs
13.5 Ibs
4.4 Ibs
Reduction
with
MAGNUSCRUBBER
46%
61%
46%
32%
200
-------
Table 5. TOMATO CANNING. REDUCTION OF TOTAL PLANT WASTES
WITH MAGNUSCRUBBER
For total plant
Water flow
Biological Oxygen
Demand
Chemical Oxygen
Demand
Suspended solids
pH of water waste
Peel removal method
per 1,000 Ibs of canned tomatoes
Water washing
3,750 gals.
49.3 Ibs
93.2 Ibs
45.3 Ibs
9.4
MAGNUSCRUBBER
2,690 gals.
31.4 Ibs
44.5 Ibs
-
6.2
Reduction
with
MAGNUSCRUBBER
28%
36%
52%
-
-
201
-------
this material is very high in desirable red pigment. Of course, the
material contains caustic (NaOH), but this can be neutralized with
hydrochloric acid (HC1) and converted to common table salt (NaCl) and
water. Salt is ordinarily added to tomato products for flavor ariyway.
This project will be the subject of another paper at this seminar. It's
enough to say that it is very likely that the tomato peel fraction can
be processed into high quality tomato products for human consumption.
This would provide greatly increased produce recovery and would
eliminate 75 percent of the waste disposal problem. Could there be a
better pollution solution than that?
202
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REFERENCES
1. Graham, R. P., M. R. Hart, J. M. Krochta, and W. W. Rose. Cleaning
and Lye Peeling of Tomatoes Using Rotating Rubber Discs. Western
Regional Research Center, US Department of Agriculture. National
Canners Association Publication No. 2704. 1974.
2. Gray, L. R. and M. R. Hart. Caustic Peeling of Cling Peaches to
Reduce Water Pollution: Its Economic Feasibility. US Department
of Agriculture, Agricultural Economical Report No. 234. 1972.
3. Stone, H. E. Dry Caustic Peeling of Clingstone Peaches on a
Commercial Scale. US Environmental Protection Agency,
Environmental Protection Technology Series. Report No. EPA-660/2-
74-092. 1974.
4. Wilson, J. Properties of Wastes From Conventional Peeling Versus
Dry Caustic Peeling of Peaches and Tomatoes. CH2M-Hin, San
Francisco. Project No. F8736.0. 1975.
BIBLIOGRAPHY
Anon. Tomato Canner Eases Labor Squeeze with Automation. Food
Production/Management, p. 16. October 1972.
Mercer, W. A. and J. W. Rails. Dry Caustic Peeling of Tree Fruit for
Liquid Waste Reductions. US Environmental Protection Agency, Water
Pollution Control Series. Report No. 12060 FQE. December 1970.
Ostertag, R. and K. Robe. Waterless Peel Removal. Food Processing, p.
60. January 1975.
Rails, J. W., W. A. Mercer, R. P. Graham, M. R. Hart, and H. J.
Maagdenberg. Dry Caustic Peeling of Tree Fruit to Reduce Liquid
Waste Volume and Strength. US Environmental Protection Agency,
Water Pollution Research Series. Report No. 12060. 137 p. 1971.
203
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A FRUIT PROCESSORS WASTE TREATMENT EFFLUENT VARIABILITY AND
PLANNING FOR ATTAINMENT OF 1983 EFFLUENT GUIDELINES
Larry A. Esvelt*
INTRODUCTION
Snokist Growers, a cooperative, operates a fruit cannery at Yakima,
Washington. In 1966 the cannery began construction of a wastewater
treatment system and was assisted by a research and development grant
from the Federal Water Pollution Control Administration, now the US
Environmental Protection Agency (EPA). Their wastes were treated in a
newly constructed aerated lagoon system during the 1967 processing
season which was upgraded to a complete mixed activated sludge system
with capability for limited sludge reaeration by the 1968 processing
season. The results of the research and development study connected
with the treatment system indicated that biological treatment was
feasible for fruit processing wastes.1'2 Biological oxygen demand (BOD)
removals by the complete mixed activated sludge system, with nutrient
addition, exceeded 99 percent during the 1968 processing season.
Biological uptake rate and sludge growth parameters were developed
during the research and development study to allow application of the
treatment system at other locations.
The Water Pollution Control Act Amendments passed by Congress in
1972 directed that industries provide Best Practicable Treatment of
wastewaters by 1977 and employ Best Available Treatment technology by
1983. EPA, the administering agency, subsequently contracted with
consultants to develop effluent limitation guidelines for compliance
with this directive. Snokist Growers wastewater treatment system was
cited as producing an exemplary effluent in the development of
guidelines for peach, pear and apple processing industries.3'1*
*PhD, PE, Bovay Engineers, Inc., Spokane, Washington.
204
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The purpose of this paper is to discuss Snokist's wastewater
treatment facility, its adequacy to date and its anticipated adequacy
based on the guidelines for effluents developed by the EPA. This paper
will also discuss planned improvements by Snokist Growers to attain 1983
levels of best available treatment for their cannery effluent.
WASTEWATER TREATMENT FACILITIES
The wastewater treatment facilities completed for Snokist Growers'
Cannery in 1968 consist of a six million gallon aeration basin with
surface aerators totaling 390 horsepower. The aeration basin is coupled
with a 90-foot diameter secondary clarifier and sludge recirculation
capacity of 2.5 million gallons per day for normal operation and 5
million gallons per day peak capacity. A 1.5 million gallon aerated
lagoon with two 30 horsepower surface aerators is used for activated
sludge reaeration and provides the overall system with approximately 50
percent greater solids capacity. A flotation sludge thickener was
constructed in 1968 to allow thickening of the waste activated sludge
for wasting by hauling to landfill or land application.
The wastewater treatment system for Snokist Growers has performed
satisfactorily since 1968 with a few exceptions. During one processing
season, in-plant chlorination of a cooling water supply became excessive
which upset the treatment system a number of times before the problem
was identified and a remedy initiated. During another season nutrient
feed problems caused upset conditions during a portion of the year.
Otherwise the biological treatment portion of the plant has easily
provided adequate treatment but the solids wasting capacility has been
inadequate during several seasons which allowed the solids in the
biological system to build up and spill over into the effluent for short
periods.
The production of excess solids has increased since initial startup
of the wastewater treatment system due to increased processing rates and
increased wasteloads. Figure 1 shows the average daily processing rate
for pears, peaches and apples that have been maintained throughout the
processing season since 1966. Pear processing and apple processing,
which are the principal cannery activities, have each steadily risen
since that time. The 1974 processing season has seen an additional
problem arise when the energy shortage caused a threat of natural gas
delivery cut-back in the event of a severe winter which in turn
necessitated concurrent processing of apples and pears during the
earlier fall period. The result of the increased processing rate can be
seen on Figure 2 where the average COD discharge rate from the cannery
to the treatment system during the maximum processing month for each of
205
-------
300
200
1
5
0.
w
100-
I96S
-APPLES
1970
I 74
Figure 1. Processing rates - 1966 to 1974
Snokist Growers' Terrace Height Cannery.
40.0OO
I9SC 1970 1974
Figure 2. COD effluent to treatment system.
206
-------
the years Is shown. The effect of concurrent processing of apples and
pears in 1974 is also quite evident on this chart.
The fixed volume and aeration capacity of the treatment system
causes increases in loading rate on the treatment system to result in
disproprotionately larger increases in excess solids that must be
disposed of. The total biological solids in the system is limited by
solids consolidation rate in the clarifier and aeration volume which
holds endogenous respiration at a relatively constant level, while
conversion of the BOD and COD to solids increases linearly and results
in a marked increase in the net solids increase as shown in Figure 3.
The excess solids must be wasted or escape in the effluent.
The solids wasting system consisting of the sludge thickener and
accompanying pumps is marginally adequate when all facilities are in
good operating condition. The thickener increases the solids content to
only approximately 2.5 percent total solids on a consistent basis
instead of the 4 percent that was originally hoped for. This creates a
situation where an excessive amount of water must be hauled away with
the waste activated sludge solids. Any malfunctions of pumps,
recirculation system, or other portion of the sludge wasting system
results in the inability to waste sludge solids and usually results in
the loss of solids to the effluent.
EFFLUENT LIMITATIONS GUIDELINES
Effluent limitations guidelines were first developed for the apple,
potato and citrus industries of the point source food processing
category3 by a subcontractor for the EPA who used data from existing
facilities coupled with data collected during the development of the
guidelines to determine the Best Practicable Control Technology
Currently Available (BPCTCA). A later study by another subcontractor4
resulted in development of BPCTCA for the other commodities within this
point source category. BPCTCA was based on assumptions of (1) activated
sludge or aerated lagoon biological treatment for BOD removal, (2)
aerated lagoon treatment for total suspended solids (TSS) removal, and
(3) the ratio of average daily effluent to maximum day effluent taken
from activated sludge plants. The resulting BPCTCA guidelines
applicable to Snokist Growers are shown in Table 1.
The contracts awarded by EPA for development of guidelines also
resulted in recommended Best Availability Technology Economically
Available (BATEA). This technology was based on the assumption of (1)
in-plant waste reduction in volume, (2) activated sludge or aerated
lagoon treatment for BOD removal, (3) activated sludge or aerated lagoon
207
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500-
o
CO
CO
CC 400-
UJ
a.
1970
1974
Figure 3. Net biological solids production by
treatment system.
208
-------
Table 1. BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY AVAILABLE
(BPCTCA)
Apricots
Cherries (sweet
and sour)
Peaches
Pears
Plums
Apple products
Grease and oil
PH
BOD
kg/kkg (Ib/ton)
Max.
Monthly
1.0 (2.1)
0.9 (1.8)
9.5 (1.7)
1.1 (2.1)
0.28 (0.56)
0.35 (0.70)
Max.
Daily
2.5 (5.0)
2.2 (4.3)
2.0 (4.1)
2.5 (5.0)
0.65 (1.3)
1.40 (2.80)
less than 20 mg/1
TSS
kg/kkg (Ib/ton)
Max.
Monthly
1.7 (3.4)
1.4 (2.9)
1.4 (2.7)
1.7 (3.4)
0.45 (0.90)
0.45 (0.90)
within the range 6.0 to 9.0
Max.
Daily
5.0 (9.9)
4.2 (8.4)
3.9 (7.8)
5.0 (9.9)
1.3 (2.6)
1.80 (3.60)
209
-------
treatment for BOD removal, (3) activated sludge or aerated lagoon
treatment followed by mixed media filtration for TSS and additional BOD
removal, and (4) disinfection for fecal coli removal. BATEA recommended
guidelines are shown on Table 2 for products of concern to the Snokist
Growers' Cannery.
Utilizing the guideline levels for 1977 and 1973 as presented in
the EPA development documents and the rate of production levels
indicated on Figure 1, effluent limitations can be developed as they may
be included in an NPDES permit using the guideline levels. These are
shown for the 1977 and 1983 levels on Table 3 for the principal products
at Snokist Growers.
TREATMENT SYSTEM PERFORMANCE
Since Snokist Growers has kept accurate records of their effluent
characteristics since 1967, it is possible to look at the historical
variability of the effluent in relationship to the 1977 and 1983
guideline levels. Initial examination of the records indicated that it
would not be suitable to utilize 1969 and 1971 data as those were the
two years when nutrient feeding and chlorination problems upset the
treatment system. Therefore, 1972, 1973 and 1974 operating seasons were
examined in more detail to determine the extent of compliance with
proposed 1977 and 1983 guidelines levels. Table 4 shows an indication
of violations of 1977 guideline levels applied to Snokist's processing
rate, as in Table 3 during the months of August, September, October,
November and December for these three operating seasons. Violations of
the daily maximum TSS level occurred during two months in these
operation seasons. Violation of the maximum daily BOD occurred during
one month, in August, when startup of the system is annually undertaken.
The monthly average TSS guideline level was also exceeded during one
month in 1974.
Table 5 presents an indication of the frequency of violation of the
1983 guideline level for these same three operating seasons and the same
five months of operation. Here the violations are more frequent with
TSS monthly average and maximum daily potential limitations exceeded
several times during the 1972 and 1974 processing seasons and during one
month for each of them during the 1973 season. The proposed BOD
limitation was also exceeded during both the 1972 and 1974 processing
seasons.
It is not coincidental that the 1973 season shows fewer violations
of the proposed 1983 guideline levels than the years 1972 and 1974.
During each of the 1972 and 1974 seasons, equipment malfunctions
210
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Table 2. BEST AVAILABLE TECHNOLOGY ECONOMICALLY AVAILABLE
(BATEA)
Apricots
Cherries (sweet
and sour)
Peaches
Pears
Plums
Apple products
Grease and oil
PH
MPN (fecal)
BOD
kg/kkg (Ib/ton)
Max.
Monthly
0.55 (1.1)
0.38 (0.74)
0.36 (0.72)
0.42 (0.84)
0.12 (0.23)
0.07 (0.14)
Max.
Daily
1.3 (2.6)
0.90 (1.8)
0.85 (1.7)
1.0 (2.0)
0.28 (0.55)
0.28 (0.56)
less than 20 mg/1
TSS
kg/kkg (Ib/ton)
Max.
Monthly
0.55 (1.1)
0.37 (0.74)
0.36 (0.72)
0.42 (0.84)
0.12 (0.23)
0.10 (0.20)
to be in the range 6.0 to 9.0
Max.
Daily
1.6 (3.2)
1.0 (2.1)
1.0 (2.1)
1.2 (2.4)
0.34 (0.67)
0.40 (0.80)
to be less than or equal to 400 per 100 ml.
211
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Table 3. SNOKIST GROWERS EFFLUENT LIMITATIONS9
ACCORDING TO GUIDELINES
Guidelines level,
year
BOD
TSS
1977
Pears at 300 t/day
Apples at 100 t/day
Peaches at 270 t/day
1983
Pears at 300 t/day
Apples at 100 t/day
Peaches at 270 t/day
600/1500
70/280
460/1110
250/600
14/56
195/460
1020/2970
90/360
730/2110
250/720
20/80
195/570
Monthly average/maximum day, pound/day.
212
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Table 4. VIOLATIONS OF 1977 GUIDELINE LEVEL
Year
1972
BOD
TSS
1973
BOD
TSS
1974
BOD
TSS
Aug
Max.
Sep
Oct
Nov
Dec
Max.
Avg./max.
Table 5. VIOLATIONS OF 1983 GUIDELINE LEVEL
Year
1972
BOD
TSS
1973
BOD
TSS
1974
BOD
TSS
Aug
i
Max
Max.
Max.
Avg./Max.
Sep
Oct
Avg.
Avg.
Nov
Dec
Avg./Max.
Avg./Max.
Avg./Max.
Avg.
Avg./Max.
213
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occurred which precluded the wasting of sludge for a short period during
the season, whereas during 1973 it was possible to waste activated
sludge throughout the entire season. Because of the ability to waste
sludge more consistently during the 1973 season, fewer or practically no
violations would have occurred to the 1983 guideline levels, had they
been in force, until near the end of the season when even during that
optimum year, solids build-up in the system exceeded sludge wasting
capacity to the extent that some solids did escape in the effluent and
thus exceeded the proposed guideline level. During each of the 1972 and
1974 seasons, the last month of operation resulted in fairly consistent
violations of guideline levels as a result of solids buildup and
carryover.
Violations during the initial startup phases of the seasons were
not due to solids wasting capabilities. These resulted from the
imposition of a relatively heavy organic load on the unacclimated
biological system. The startup of the system in 1973 was enhanced by
the fact that crab apples had been processed in the system shortly
preceding the start of pear processing thus allowing an accumulation of
a viable activated sludge which more rapidly responded to the increased
organic load and would not have resulted in violation of even the 1983
guideline levels for BOD or TSS during pear processing startup.
However, the system would have violated pH guideline levels during each
of the three seasons when pH of the effluent during startup dropped to
below 6.0. It was necessary in each case to buffer the pH in the system
with sodium hydroxide in order to prevent the loss of excess solids and
to allow a more rapid establishment of the viable biological floe for
organic removal.
Compliance with the guidelines for oil and grease are no problem at
Snokist Growers since there is no oil or grease utilized in the process.
Compliance with the proposed 1983 guideline for fecal coliforms is
unknown at this time since equipment for monitoring these parameters was
not yet available during the 1974 processing season.
The 1973 processing season being most exemplary for the Snokist
wastewater treatment system in recent seasons appeared to be the most
logical for comparison with BATEA guidelines to determine the degree of
compliance. Table 6 shows that unit emission rate mean and range of one
standard deviation based on logarithmic averaging for flow, BOD and TSS
for the 1973 processing season. The unit emission rates based on tons
of raw product processed allow a comparison of the means achieved with
those indicated on Table 2 to ascertain the degree of compliance of this
treatment system with the BATEA guidelines. It can be observed from
Table 6 that cherry processing results in an emission rate in excess of
that indicated under the BATEA guidelines for both BOD and TSS. The
emission rate of BOD and TSS for pears and peaches (including plums
214
-------
Table 6. SNOKIST GROWERS TREATMENT PLANT UNIT
EMISSION RATE - 1973 PROCESSING SEASON*
Product
Cherries
(3 weeks)
Crab apples
(1 week)
Pears
(2 months)
Peaches and plums
(1 week)
Apples
(4 months)
Flow, gal. /ton
11,300
(8,750-14,600)
7,840
(6,930-8,880)
4,520
(4,060-3,030)
6,370
(5,270-7,100)
6,390
(4,360-9,300)
BOD, Ib/ton
0.66
(0.44-1.01)
0.63
(0.53-0.76)
0.25
(0.16-0.38)
0.22
(0.14-0.36)
0.37
(0.18-0.78)
TSS, Ib/ton
1.79
(1.20-2.66)
1.29
(0.76-2.18)
0.44
(0.31-0.63)
0.55
(0.41-0.73)
0.99
(0.39-2.50)
Log Mean = Log Mean +_ 1 Log Standard Deviation.
215
-------
which were processed concurrently) both comply with the BATEA
guidelines.
Table 6 indicates that the effluent did not comply with the BATEA
guidelines during apple processing and in fact the log mean emission
rate for the TSS exceeds the proposed maximum daily guideline under
BATEA. This points up a problem which must be faced by regulatory
agencies in developing effluent limitations from the guidelines
presented in the development documents. For a treatment system designed
for and treating a relatively heavy load of pollutants during a portion
of the processing season, and receiving a reduced pollutant load during
processing of other products, the treatment system effluent may contain
excessive pollutants on a per ton basis for the other products. This
may occur even though the operation of the facility is at its optimum.
It is potentially caused by the scale of the facility as opposed to the
pollutant load being introduced, residual solids in the system
accumulated during the treatment of the earlier, heavier pollutant load
and different characteristics of the newly introduced wastes. Colder
weather, which would normally.be expected to result in poorer treatment
performance than during warmer periods would have a relatively greater
effect on an over-designed treatment system during treatment of the
"minor" products. The development documents did not extensively
consider the effect of cold weather on treatment system performance and,
thus, the averages utilized to develop BATEA guidelines may be
excessively stringent for climatological conditions similar to those
where Snokist Growers' Cannery is located, especially if an oversized
aeration basin causes temperature effects to increase in severity.
To provide equity among discharges, the effluent limitations
developed for NPDES permits should allow for temperature effects on
treatment performance, and for startup and product changes, and for
carryover of residuals from one product to another. Limitations should
be applied to the maximum production rate and maximum waste load
generating product and the NPDES permit conditions should call for
efficient operation during other processing periods and products.
PLANNING FOR MEETING THE 1983 BATEA GUIDELINES
Snokist Growers presently has two research and development projects
underway, each of which might have a substantial effect on their
wastewater treatment operations. The two projects are: a study of the
feasibility of dewatering the waste activated sludge and utilizing the
dewatered sludge as a cattle feeding supplement; and a study of the
feasibility of reusing the treated effluent from the activated sludge
system, following polishing on multimedia filters and chlon nation,
216
-------
inside the cannery as a water supply source. Each project is partially
supported by research and demonstration grant funds from EPA; and Mr.
James Santroch and Mr. Harold Thompson are project officers.
Utilization of Waste Activated Sludge in a Cattle Feeding Ration
Snokist Growers is working under EPA Grant Number S803307 in
studying the feasibility of dewatering waste activated sludge using a
basket centrifuge and the utilization of the dewatered sludge in a
cattle feeding ration. The study is approximately 50 percent complete
and shows considerable promise although the overall economic and final
conclusions as to the acceptability of the solids as a cattle feed are
not yet evaluated. Any final conclusions must be deferred until the
study is completed and the data finalized. To date, the waste activated
sludge solids from the sludge thickener are being dewatered in a
prototype scale basket centrifuge to approximately 8 to 9 percent dry
solids without utilizing any thickening aids or chemicals. Pilot scale
centrifuge tests did not indicate that variation in centrifuge speed
affected the final product total solids content appreciably. The solids
level attained was approximately the same on both the pilot scale and
the prototype scale centrifuges which were respectively 14-inch diameter
and 30-inch diameter basket machines. The solids dewatering capability
attained seems to compare favorably to that experienced utilizing waste
activated sludge from potato processing waste treatment system5 where
only up to 7 percent solids were attained using a pilot scale
centrifuge.
The solids have been fed to three groups of six steers each in
varying proportions of their ration, and a fourth group of six steers is
used as a control group. The feeding portion of the study is conducted
at the Washington State University Irrigation Agriculture Research and
Extension Center in Prosser, Washington. The performance of the steers
through the first 84 days on the feed rations is shown on Table 7. It
can be seen that there is a possible benefit of the waste activated
sludge in the ration at low concentraitons as the weight gain for Ration
No. 1 with 2.3 percent dry activated sludge solids appears to be greater
than for the control or for the other two rations. Ration No. 2 with
4.6 percent dry solids appears to be approximately the same as the
control ration. If the final results show a beneficial effect of the
sludge, there may be sufficient value placed on the sludge for its
inclusion in cattle feeding rations by commercial feed lot operators.
The sludge is approximately 40 percent protein on a dry matter basis.
If the waste activated sludge does have sufficient value for a
cattle feeder to underwrite the costs of hauling the sludge away from
the treatment facility, dewatering of the sludge could show an economic
217
-------
Table 7. RESULTS OF WASTE FRUIT PROCESSING ACTIVATED SLUDGE IN
CATTLE FEED RATIONS - AFTER 84 DAYS
Animal group
Control
Ration No. 1
Ration No. 2
Ration No. 3
Sludge in ration
% D.S.
0
2.3
4.6
9.3
Weight gain,
kg/day (Ib/day)
1.26 (2.78)
1.44 (3.17)
1.21 (2.67)
1.12 (2.47)
218
-------
benefit since the present practice of hauling the waste activated sludge
in its liquid form at only 2.5 percent solids is a substantial cost to
the cannery. Even if the solids are not worthwhile for use as a cattle
feed there may be some economic advantage to dewatering in savings in
hauling and disposal costs. Similar sludges have been reported
beneficial in poultry feed rations at concentrations up to 7.5 percent.6
Wastewater Reuse Project
The wastewater reuse project, EPA Number S803280, is presently in
its first year during which facilities are being constructed to enable
the cannery to reuse up to 1 million gallons per day of treatment
effluent inside the cannery as a source of water. The particular uses
for which the water will be made are as yet undetermined but
investigation of the consistency of water quality will be extensive
during the 1975 operating season and the water will be used in pilot
studies for washing down equipment, washing floors and gutters, initial
fruit transport, utilization for belt wash and as steam generation make-
up. Chemical and bacteriological monitoring of the polished effluent
will show the consistency of reused water quality and the suitability of
the water for potential uses.
Two 8-foot diameter multimedia filters (anthracite, silica sand and
garnet), a chlorination system which will include automatic chlorine
residual monitoring and control, and reuse pumps have been purchased by
Snokist Growers for delivery in May and early June. A contract has been
awarded for the construction of a filter and chlorination building and
installation of equipment and piping prior to the startup of pear
processing for the 1975 season.
Pilot filter studies were planned for the 1974 operating season but
the moving up of the apple processing to coincide with pear processing
and delays in getting equipment for filtering and laboratory analyses
resulted in the processing season terminating approximately the time the
pilot filter system was ready for operation. A subsequent softening of
the market for canned apple products has resulted in the winter cannery
operation being delayed and possibly cancelled for the remainder of this
processing season which may result in the pilot filter operation not
being undertaken.
If water reuse investigations show success in the 1975 season, a
more comprehensive utilization of the polished effluent will be
undertaken in 1976 to demonstrate that the effluent quality is suitable
for reuse in all processing areas except direct make-up to the product
cans, such as in syrups. The most critical quality area for the reuse
219
-------
of water will be that of direct cooling which will be investigated
during the 1976 processing season.
i
Figure 4 shows the wastewater treatment system schematic flow
diagram as it presently exists and as it will be added to with the
effluent polishing system for wastewater reuse and with the potential
solids dewatering system. It is hoped that with these two improvements,,
the quantity of wastewaters and their contained pollutant load can be
reduced to the extent that the effluent will meet 1983 guideline levels
consistently and without difficulty. One area not shown on Figure 4
which may be necessary is disinfection of the effluent portion going to
the river. It is presently anticipated that reuse of water in the
cannery will be only up to approximately 50 percent. However, the
capability will be installed for recycle and reuse of the treated
effluent up to approximately 80 percent during apple processing should
the reused water be acceptable in all processes in the cannery.
ACKNOWLEDGMENT
The data for this paper was supplied by Mr. Herb H. Hart,
Laboratory Director at Snokist Growers' Cannery. A portion of the data
analysis was provided by Mr. Kenneth Dostal of EPA in Corvallis, Oregon.
220
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SCREENED
WA.STE
NUTRIENT ADDITION
METERING BOX
SLUDGE
REA.ERATION
&KSIN
CENTRIFUGE [ 1
SLUDGE I J
DEWATERING I
EFFLUENT
TO RIVER
SLUDGE T DISPOSAL
THICKENER
TO CATTLE
FEED
WA3TE FLOW
RETURN SLUDGE FLOW -ACTMTED SLUDGE
RETURN SLUDGE FLOW - ACTIVATED SLUDGE. WITH 5LODGE REAERATION
ADDITIONS TO EXISTING TREATMENT PLANT
Figure 4. Wastewater treatment system,
Snokist Growers' Cannery.
221
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REFERENCES
1. Esvelt, L. A. Aerobic Treatment of Fruit Processing Wastes.
Federal Water Pollution Control Administration, Department of the
Interior. Report No. DAST 8. 1969.
2. Esvelt, L. A. and H. H. Hart. Treatment of Fruit Processing Waste
by Aeration. J. of Water Pollution Control Federation. 42:1305.
1970.
3. US Environmental Protection Agency. Development Document for
Proposed Effluent Limitations Guidelines and New Source Performance
Standards for the Citrus, Apple and Potato Segment of the Canned
and Preserved Fruits and Vegetables Processing Point Source
Category. 1973.
4. Soil Conservation Service Engineers. Draft Development Document
for Effluent Limitations Guidelines New Source Performance
Standards for the Canned and Preserved Fruits and Vegetables
Industry Point Source Category, Phase II. US Department of
Agriculture for the US Environmental Protection Agency. 1974.
% *
5. Richter, G. A., K. L. Sirrine, and C. I. Tollefson. Conditioning
and Disposal of Solids from Potato Processing Wastewater Treatment.
J. Food Sciences. 38_:218. 1973.
6. Jones, R. H., J. T. White and B. L. Damron. Waste Citrus Activated
Sludge as a Poultry Feed Ingredient. US Environmental Protection
Agency. EPA Report No. EPA-660/2-75-001. 1975.
222
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TOMATO CLEANING AND WATER RECYCLE*
Walter W. Rose**
Allen M. Kat
George E. Wilson***
Part I: Cleaning of Tomatoes
INTRODUCTION
In 1972, engineers at the US Department of Agriculture's Western
Regional Research Center (WRRC), Albany, California, conducted some
exploratory tomato cleaning research, using the concept of flexible,
spinning rubber discs.1 This study did indicate that mechanical energy,
in the form of rotating discs, could substitute for most of the
hydraulic energy, large volumes of water, in cleaning the surfaces of
tomatoes. This study also indicated that large numbers of stems could
be removed from tomatoes as they were being cleaned.
On the basis of the exploratory work, a cooperative project between
WRRC and the National Canners Association (NCA) was carried out in
1973.2'3 This project evaluated the rubber disc concept for the
cleaning and peeling of tomatoes. An integrated pilot scale system was
operated at a cannery throughout the 1973 processing season. Data was
developed to indicate a substantial reduction in the need for water to
clean and peel tomatoes.
*This investigation was supported by funds from the US Environmental
Protection Agency, Pacific Northwest Environmental Research Laboratory,
under Grant Number S803251-01.
**National Canners Association, Western Research Laboratory, Berkeley,
California.
***Eutek Process Development and Engineering, Sacramento, California.
223
-------
With the cooperation and assistance of an industry ad hoc
committee, the NCA prepared a project for consideration by the US
Environmental Protection Agency (EPA). The project was designed to
demonstrate, on a commercial basis, the cleaning of tomatoes with a
rubber disc machine and to develop a water recycle system for dump tank
water. Part I of this 'paper will discuss the cleaning of tomatoes.
Part II will discuss the development of a water recycle system.
EXPERIMENTAL PLAN AND PROCEDURE
A tomato cannery was located which processed all of the tomatoes
from a single bin dumper. The processor did not receive bulk loads of
tomatoes nor did it peel any tomatoes. This was ideal from a project
evaluation view-point as it permitted a comparison with the conventional
washing system and the proposed demonstration system. The water recycle
system was also confined to a single operation and the impact of this on
the overall quality of water discharged from the plant could be
determined.
. Figure 1 is a schematic representation of the processing operations
involved in dumping, transporting and washing of tomatoes by the
conventional and the demonstration systems. Included in the schematic
is an indication of water flows and sampling points.
Prior to startup of the processing season, several changes were
made by the processor which significantly altered the amounts of water
used in the cleaning of tomatoes. The first and second stage washes
were combined into a single flood washer. Water sprays were eliminated
from these two operations as well as from the dump tank elevator. A
true counter flow system of water was employed. Fresh water was used as
a final rinse for tomatoes on the inspection belt. The distribution
flume combined first and second stage washes and the dump tank each had
independent recirculation loops. The final rinse water co-mingled with
the distribution water, with the excess water flowing into the combined
washer water. The excess water from this recirculation loop flowed back
to the dump tank recirculation system, with the excess water being
discharged to the gutter.
On a continual use basis, the final rinse water was the major
source of water entering the counter flow system. A secondary source
was water used to rinse bins after dumping of tomatoes. This rinse
water entered the dump tank and added to the water volume being
continually discharged. On an intermittent basis, water to fill the
dump tank, inside washer and distribution flume added to the total water
used to process the tomatoes. The only other source of water associated
224
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WATER IN
BIN DUMPER
CONVENTIONAL LINE = DEMONSTRATION LINE
DUMP TANK
== 1
= 1
FIRST STAGE
WASHER
SSS 1
= 1
••VBM 1
SECOND STAGE
WASHER
E| 1
DISTRIBUTION
FLUME
H|
INSPECTION
BELT
d
\
D 0
\ 1
D
^
DUMP TANK
®|
DISC
CLEANER
m|
DISTRIBUTION
FLUME
m|
INSPECTION
BELT
V
KEY
( — i _ .
WAI
1
1
1
^
1
I
-4-
D PRODUCT SAMPLING POINTS
O WATER SAMPLING POINTS
WATER IN OR OUT
WATER RECIRCULATION
Figure 1. Sampling points for conventional versus
demonstration cleaning systems.
225
-------
with the processing of tomatoes was that used for clean-up purposes
either during operations or at scheduled shut downs.
A sampling program was revised to reflect the modifications made by
the processor. The product was evaluated for cleanliness by collecting
tomato samples from the following locations.
1. Bin before dumping
2. After the dump tank
3. After the combined inside washer
4. After final rinse
Product samples from the demonstration system were collected from
the following locations:
1. Bin before dumping
2. After the dump tank
3. After disc cleaner
4. After final rinse
Every 4 hours approximately 5 pounds of tomatoes were collected
from the four sampling locations of either the conventional or the
demonstration system. After weighing, water equal to twice the weight
of tomatoes was added to the tomatoes held in a wire mesh basket that
fit inside a plexiglass cyclinder. The tomatoes were shaken for two
minutes, then some of the water was transferred to a sterile plastic bag
and some to a quart plastic bottle. For each 8-hour period, two of the
4-hour samples were combined, ending up with three 8-hour samples per 24
hours.
All samples were held under refrigeration until transported to the
Berkeley laboratory for analysis. Samples in sterile plastic bags were
analyzed for total plate count and mesophilic aerobic spores.** Samples
in the plastic bottles were analyzed for suspended and fixed suspended
solids.6
Water samples were collected from the following locations:
1. Distribution flume overflow
2. Inside washer overflow
3. Dump tank overflow to gutter
4. Inside collection gutter
5. Disc cleaner effluent
Samples were collected from the above locations on a 24-hour basis
with automatic timed samplers. Samples were analyzed for BOD, COD,
226
-------
suspended and fixed suspended solids.5 Water and product washing
samples were collected six days per week. Water meter readings were
made during each 8-hour shift.
Figure 2 is a photograph of the disc cleaner. The disc bed is 5
feet wide by 10 feet in length. The bed is inclined upward some 16
inches over the 10 foot length. The discs are mounted on shafts with 3-
1/2 inch center. Rotation is by means of a chain and gear arrangement
with the initial torque coming to the two front chains. Speed of
rotation could be varied but was maintained at 400 revolutions per
minute for the duration of the study. Bearings were lubricated by means
of an adjustable timed interval system.
Above the disc bin were installed two types of spray systems. One
consisted of three evenly spaced manifolds that contained hollow cone or
fogging nozzles. The second spray system consisted of four manifolds of
flat jet nozzles. The cleaner could be operated with either the hollow
cone nozzles for minimal water or a combination of hollow cone and flat
jet nozzles. Normal practice was to operate the sprays at 40 pounds
pressure.
RESULTS
The initial test phase of the program was to collect data from the
disc cleaner and the conventional washing system for comparative
purposes. For two days, the disc cleaner was operated over short
periods of time with several tomato samples being collected. During
these two days, several samples were also collected from the
conventional washing system. For some of the runs, the cleaner operated
with only the low water hollow cone nozzles and for other runs a
combination of the two sprays was utilized.
A summary of the results for this test phase is given in Table 1.
Results are given for fixed suspended solids and mesophilic aerobic
spores, two indicators of the cleanliness of tomatoes.
Results in Table 1 for the disc cleaner indicate the importance of
supplementing the mechanical energy of the rotating discs with some
water. Results from the cleaner are much better when operated with a
combination of sprays rather than with the mist type hollow cone
nozzles.
Results for the final rinse of the conventional system did give the
best results. However, this could be expected as tomatoes are in
contact with water for a longer period of time. Also, the volume of
227
-------
Figure 2. Disc cleaner,
-------
Table 1. SUMMARY OF INITIAL TEST RESULTS
Cleaning system
Conventional
washing system
Location
Bin
Dump tank
Inside wash
Final rinse
Disc cleaner with
hollow cone
nozzle
Location
Bin
Dump tank
Disc cleaner
Disc cleaner with
combination of
nozzles
Location
Bin
Dump tank
Disc cleaner
Fixed suspended
ppm
86
59
38
6
ppm
82
50
27
ppm
116
81
14
solids
% red.
-
31
56
93
% red
-
39
67
% red
-
30
88
Mesophilic aerobic
per ml
2,461
562
147
50
per ml
1,067
731
198
per ml
3,230
1,178
140
spores
% red
-
77
94
98
% red
-
31
81
% red
-
64
96
229
-------
water to process the tomatoes Is greater. Should the disc cleaner
results be compared to those from the inside washer, then tomatoes from
either system are equally clean.
Results of this test program were discussed with cannery personnel
and with the visual observations of the tomatoes during the test phase,
concurrence was given to initiate the evaluation. For the remainder of
the season, either the conventional or the demonstration system was
operated on a continuous 24-hour basis. The normal procedure was to
operate the disc cleaner for 4 days, followed by 2 days of conventional
processing. Tables will be given to illustrate seasonal averages for
various conditions of operation.
Table 2 gives results for tomato samples collected from various
sample locations. Results are given for total plate count (TPC) and
mesophilic aerobic spores (MAS). Results are tabulated for the
conventional washing system and for the disc cleaner operated with the
two types of spraying arrangements.
The results given in Table 2 follows a similar pattern obtained
from the initial test phase. For the disc cleaner results are better
when operated with a combination of sprays rather than the hollow cone
nozzles. The best results were obtained from tomatoes sampled after the
final rinse. The spread in percent reduction of spores for the two
types of sprays on the cleaner is not as great on a season average as
compared to the initial test results. The percent spread for the
initial results between hollow cone and combination of sprays was 81
percent versus 96 percent; seasonal summary results were 77 percent
versus 81 percent. The disc cleaner results, compared to those from the
washer of the conventional system are much better than those indicated
by the preliminary test program. This may be the result of sampling
over a longer period of time and reflect the tendency for bacteria to
grow in water which has been recirculated for extensive periods of time.
Table 3 is a summary of suspended and fixed suspended solids for
tomatoes sampled under three cleaning modes. The general pattern for
these results is similar to those presented in Table 2 for total plate
count and mesophilic aerobic spores. Of the two solids parameters,
fixed suspended solids more closely fits the pattern for the bacteria
data. This would suggest that fixed suspended solids might serve as a
quick indicator of microbial quality, especially mesophilic aerobic
spores. Spores and fixed suspended solids are normally associated with
soil load.
Total suspended solids, as mentioned above, fits the general
reduction pattern obtained from Table 2. However, suspended solids is
highly influenced by the quality of the incoming fruit (soft versus hard
230
-------
Table 2. CLEANING OF TOMATOES - SUMMARY OF TOTAL PLATE COUNT (xlO'*)
AND MESOPHILIC AEROBIC SPORES, PER GRAM OF TOMATOES
Cleaning system
Conventional washing
system
Location
Bin
Dump tank
Washer
Final rinse
Disc cleaner with
hollow cone nozzle
Location
Bin
Dump tank
Disc cleaner
Disc cleaner with
hollow cone and
flat jet nozzle
Location
Bin
Dump tank
Disc cleaner
TPC
Avg.
1,841
1,167
702
141
Avg.
1,743
827
243
Avg.
1,456
1,414
228
% red.
-
37
62
92
% red.
-
53
86
% red.
-
3
84
MAS
Avg.
1,043
971
612
86
Avg.
1,862
1,532
432
Avg.
1,946
1,040
379
% red.
-
7
42
92
% red.
-
18
77
% red.
-
46
81
231
-------
Table 3. CLEANING OF TOMATOES - SUMMARY OF TOTAL AND
FIXED SUSPENDED SOLIDS, PARTS PER MILLION
Cleaning system
Conventional washing
system
Location
Bin
Dump tank
Washer
Final rinse
Disc cleaner with
hollow cone
nozzle
Location
Bin
Dump tank
Disc cleaner
Disc cleaner with
hollow cone and
flat jet nozzle
Location
Bin
Dump tank
Disc cleaner
TSS
Avg.
189
179
99
46
Avg.
213
153
114
Avg.
205
109
84
% red.
-
5
48
76
% red.
-
28
46
% red.
-
47
59
rss
Avg.
Ill
86
30
8
Avg.
119
69
30
Avg.
129
48
18
,
% red.
-
22
73
93
% red.
-
42
75
% red.
_
63
86
232
-------
or overripe versus underripe) and as such should more closely correlate
with the BOD or COD content on the processing waters rather than the
sanitary quality. No attempt has been made to look at the raw data to
determine if this is in fact true.
Table 4 is a summary of water used and waste generated. Results
are expressed as gallons per ton of tomatoes processed or pounds of COD
per ton of tomatoes processed.
Certain estimations and assumptions were made in order to develop
some of the data in Table 4. The volume of water used in the final
rinse was metered; therefore, the 130 gallons per ton is an accurate
figure. To calculate the pounds of COD per ton, it was assumed that the
130 gallons per ton of rinse water did co-mingle with the distribution
flume circulation loop and that a sample of the excess water was an
indication of the waste generation for the final rinse-distribution
f1ume.
Some 1,981 gallons per hour of water was used inside the plant.
Some of this water was used to fill the flood washer and some was used
for clean-up purposes. Since the volume of water for each is not known,
it is assumed that 25 percent of the water was for the flood washer and
75 percent was used for hosing down. To calculate the pounds of COD, it
was assumed that the 130 gallons per tons of excess water from the
distribution-final rinse and 25 percent of the 1,981 gallons per hour
(16 gallons per ton) overflowed from the flood washer recirculation
system.
The dump tank overflow was derived by assuming total excess flow
from the inside washer plus bin washing water. The excess overflow was
assumed to be 146 gallons per tons and the bin rinse water to be 20
gallons per ton. The inside gutter, a measure of all water used in the
washing and transporting of tomatoes, is the sum total of the excess
water from the bin dumping and that water used for cleaning.
Table 4 also gives the water and waste generation for the disc
cleaner when operated under the two types of spray arranagement. Water
usage by either mode is significantly lower than the other operations
and supports the concept of using mechanical energy as a major
substitute for hydraulic energy.
DISCUSSION
As discussed in Part II on the development of a water recycle
system, a high velocity of water in the dump tank was required to
233
-------
Table 4. WATER AND WASTE GENERATION - SUMMARY
System
Final rinse -
distribution flume
Inside washer
Dump tank
Inside gutter
Disc cleaner - hollow
cone nozzle
Disc cleaner -
combination nozzles
Gallons/ton
130
146
166
216
3.3
24.7
Pounds COD/ton
1.0
2.44
2.02
2.23
0.1
0.42
234
-------
prevent soil deposition. This considerably shortened the contact time
between water and tomatoes and may have resulted in insufficient wetting
time. The result of this short exposure time would be tomatoes
delivered to the disc cleaner that-still contained dried surface soil.
Since the residence time of tomatoes on the disc is short (less than 30
seconds) it is important that smear soil be thouroughly wetted before
being removed.
To increase the product-water contact time, it has been suggested
that the dump tank be reconstructed with a false bottom. The water
velocity above the dump tank bottom could be decreased. Below the false
bottom, a high water velocity could be maintained to scour and transport
the soil towards the water recycle pump intake.
During the course of the study, it was observed on several
occasions that clods of dirt were being collected in the distrubition
flume following the disc cleaner. This is another indication that there
was insufficient residence time in the dump tank. The advantages from
increasing this residence time would be the possible improvement to
tomatoes being cleaned by the discs and maintenance of a higher quality
distribution flume water.
Near the end of the season, it was noted that some of the cleaner
discs were separating at the fillet juncture. This situation became
progressively worse with time and, at the conclusion of the test
program, it was estimated that over 25 percent of the discs had
separated at the fillet. This matter was brought to the attention of
several concerned parties, with agreement that the problem was caused by
having too sharp of an angle between the thick and thin part of the
disc. It has been recommended that new discs be manufactured which have
a greater taper at the fillet juncture.
Some other minor modifications should be made on the disc cleaner
as a result of observations made during the study period. The two side
walls need to be increased by approximately 4 inches to prevent
occassional tomatoes from bounding off the disc bed and onto the floor.
Permanent spray headers should be installed and their height above the
disc bin should be increased to improve clean up and appearance. There
is a need to improve the drive mechanism. The two main drive chains
were stretched and had to be tightened several times. The two small
chains at the front of the cleaner also stretched and had to be
tightened. These matters have been brought to the attention of the
manufacturer and solutions have been suggested that should be
incorporated into the cleaner before it is operated another season.
As operated in 1974, it is difficult to assess the water savings
and/or the benefits to be derived from the operation of the disc
235
-------
cleaner. With the present set-up, tomatoes are fTurned to the final
inspection belts and given a final rinse. This rinse water is added
back to the distribution flume as make up water. After several uses
this water is eventually discharged from the dump tank.
When the disc cleaner is used, there is no need for the inside
washer. As previously indicated, some 1,981 gallons of water per hour
is used for either filling the washer or hosing down the inside area.
Therefore, a potential water savings, from the use of the disc cleaner,
could be the total elimination of that water or 33 gallons per ton. If
the disc cleaner is operated with hollow cone nozzles (3.3 gallons per
ton), the water reduction would be approximately 30 gallons per ton or
20 percent reduction in total water usage.
Another benefit from the use of the disc cleaner, and this aspect
has not been fully evaluated, is the potential for a higher quality of
water in the distribution flume recirculation system. Limited data on
this water system, compared when the two types of cleaning systems are
used, indicated the water to be cleaner when the disc cleaner is used.
For example, fixed suspended solids is lower (180 versus 229) as is
suspended solids (391 versus 431) and COD (847 versus 1,126). If the
combination of sprays is used, rather than the hollow cone nozzles, then
the comparison is even better, for fixed suspended solids (180 versus
229), suspended solids (256 versus 431) and COD (800 versus 1,126).
However, water is increased from 3.3 gallons per ton to 24.7 gallons per
ton.
236
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REFERENCES
1. Krochta, J. M.t G. S. Williams, R. P. Graham, and D. F. Farkas.
Reduced-Water Cleaning of Tomatoes. Food Processing Waste
Management. Proceedings of 1973 Agricultural Waste Management
Program, Cornell University, Ithaca, New York. 1973.
2. Krochta, J. M., R. P. Graham, and W. W. Rose. Cleaning of Tomatoes
Using Rotating Rubber Discs. Food Technology. 28_(12):26. 1974.
3. Hart, M. R., R. P. Graham, and G. S. Williams. Lye Peeling of
Tomatoes Using Rotating Rubber Discs. Food Technology. 28_(12):38.
1974.
4. National Canners Association. Laboratory Manual for Food Canners
and Processors, Volume I, 3rd edition. 1968.
5. Standard Methods for the Examination of Water and Wastewater, 13th
edition. 1971.
237
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TOMATO CLEANING AND WATER RECYCLE
Walter W. Rose
Allen M. Katsuyama
George E. Wilson
Part II: Dump Tank Water Recycle System
INTRODUCTION
On March 15, 1974, the National Canners Association Research
Foundation, Berkeley, California, submitted a proposal entitled, "Tomato
Cleaning and Water Recycle", to the Grants Administration Division of
the US Environmental Protection Agency. Subsequent to this submitted
document, it was decided that EUTEK Process Development and Engineering
would be responsible for the design, construction, and operation of the
water recycle system. The design work officially began with project
authorization in mid-June. Fabrication of the settleable solids removal
unit processes was completed by the end of August. Testing of the
settleable solids removal system was initiated during the first half of
the month of September. The flocculation system was completed and tests
were initiated by September 20. The tomato processing season was
terminated during the first week of October.
The objective of the test program was to determine if it would be
feasible to maintain a closed loop system of water usage around the
tomato bin dump. Under normal operating circumstances, substantial
quantities of overflow waters are discharged from the bin dump in order
to maintain control of accumulations of settleable solids within the bin
dump and suspended solids in the bin dump waters.
Another major objective of the water recycle system was to prevent
accumulation of settleable solids within the bin dump and to remove
these settleable solids in an elevated thickener which would allow their
disposal as a solid waste. The third major objective of the test
238
-------
program was to determine what benefit was to be gained through employing
a flocculation system for suspended solids removal in conjunction with
the settleable solids removal system.
EXPERIMENTAL PLAN
System Design
Figure 1 is the flow diagram of the water recycle system as
proposed for the 30 tons per hour tomato bin dump. The system operates
either with or without flocculation. Operating without flocculation,
the primary pump transfers water from the base of the elevator to the
swirl concentrator. Concentrated settleable solids continuously
discharge from the swirl concentrator to the thickener located below.
This underflow is orifice-restricted to a constant flow of 50 gallons
per minute. The balance of the recycled water overflows from the swirl
concentrator and discharges through return scouring jets located in the
base of the bin dump. The clarified underflow stream overflows from the
thickener and returns to the bin dump.
An additional scouring jet header operates directly off the primary
pump discharge line. This additional flow is required to obtain design
flows through the scouring jets.
Supply water for the flocculation system was taken from the swirl
concentrator overflow water returning to the scouring jets. Coagulant
added to this flow and mixed through a mixing section resulted in a
flocculated admixture from the Flocculator/Concentrator. The clear
water overflow returns directly to the bin dump while the underflow
returns to the thickener for gravity clarification.
System Construction
All elements of the system were fabricated with the exception of
the primary and secondary supply pumps, valves, and piping. Figure 2
shows a view of the elevated swirl concentrator thickener assembly
following construction.
System Operation
The experimental plan called for operation of the water recycle
system in an operating mode for settleable solids removal and an
239
-------
bO
*-
o
O
FLOCCULATOR
CONCENTRATOR
SWIRL
CONCENTRATOR-
CLEARWATER
S/C PRESS
PUMP
Figure 1. Flow diagram of water recycle system.
-------
Figure 2. Swirl Concentrator/Thickener.
241
-------
operating mode for both settleable solids and suspended solids removal.
The former mode utilizes only the swirl concentrator and thickener and
the latter mode also employs the Flocculator/Concentrator. Following
completion of tests in both operating modes, the data was analyzed and
subsequent tests were conducted to better determine system operating
characteristics.
EXPERIMENTAL RESULTS
Hydraulic and Mass Balances
Problems were encountered due to accumulation of grass and vines in
the water recycle system. Water flow rates varied significantly from
one test day to the next. On some operating days, meters monitoring
accumulated water flows were found plugged and inoperative, throwing
into doubt the value of data collected during that time. The grab
sampling technique employed to determine the swirl concentrator removal
efficiencies did not account for the rapid and significant changes in
settleable solids concentrations due to the irregular nature of the bin
dump operation. Due to the difficulty of keeping accurate records of
the actual operating periods of the water recycle system, the record
sheets had several gaps in them.
To arrive at an estimate of the system performance selected
operating days were taken which had reasonably long operating periods as
evidenced by the amount of sludge removed from the thickener.
Accumulated sludge removal records were extrapolated to arrive at
estimates of operating periods in order to make hydraulic and mass
balances.
Figure 3 defines and summarizes the abbreviated notation and format
for the hydraulic and mass balances.
Table 1 summarizes the hydraulic and mass balance relationships
employed to arrive at estimates of the system flows, loadings and
efficiencies. Metered and calibrated flows in the system were used as
shown on Table 1 to compute the unknown flows. Mass balances were
obtained as shown. The quantity on the left hand side of the equation
was determined as a function of the quantities on the right hand side.
Table 2 summarizes the flows and loadings for the selected
operating days for performance comparisons of the system with and
without flocculation. As previously mentioned, the record of solids
removal from the thickener was used to determine the effective operating
242
-------
SC IN : SC INFLOW
SCU: SC UNDERFLOW
to
SCO: SC OVERFLOW
SC:
SWIRL
CONCENTRATOR
FLOCCULATOR
F.U. : FLOCCULATOR
UNDERFLOW
TU: THICKENER UNDERFLOW
TO: THICKENER OVERFLOW
METER ( I )
FO: FLOCCULATOR OVERFLOW
Figure 3. Flow diagram for hydraulic and mass balances.
-------
Table 1. HYDRAULIC AND MASS BALANCE RELATIONSHIPS
1. Hydraulic balances, mgd
a. QSCIN = QSCO + QFOa + QFUb + QSCUC
b. QTO = QSCU + QFU - QTU
2. Mass balances, Ibs
a. SCU = TU + TO - FU
b. SCIN = SCO + FO + SCU
3. Efficiencies
a. Thickener removal, %: 100 TU/(SCU + FU)
b. Overall removal, 35: 100 TU/SCIN
4. Concentration factor
a. Swirl concentrator factor: (^SCIN/%CU) (SCU/SCIN)
aConstant flow of 0.043 mgd when floe, system operating.
Constant flow of 0.058 mgd when floe, system operating.
Constant flow of 0.072 mdg at all times.
244
-------
Table 2. SUMMARY OF FLOWS AND LOADINGS'3
bO
*>
01
Operating
period,
Date days
Without
flocculation
13 Sep 0.83
17 Sep 0.71
With
flocculation
20 Sep 0.67
27 Sep 0.28
SCIN
mgd
0.230
0.438
0.337
0.286
Ib
2,436
2,228
5,122
1,429
SCO
mgd
0.158
0.366
0.164
0.217
Ib
3,062
2,264
1,393
1,622
FO
mgd
-
-
0.043
0.043
Ib
-
-
365
222
FU
mgd
-
-
0.058
0.058
Ib
-
-
493
430
TO
mgd
0.070
0.070
0.127
0.127
Ib
210
204
44
123
TU
mgd
0.015
0.010
0.015
0.006
Tb
899
1,209
6,262
2,286
a
Lb TSS except TU which is Ib TS.
-------
period for the system on each selected day. This assumption was based
on the constant flow to the thickener and the assumption that the
measured composite solids concentration was the average concentration of
all sludge volumes. Figure 4 is a plot of cumulative thickener
underflow volumes versus the time of day at which these volumes were
removed. The envelope line over the data points was assumed to
represent the average solids accumulation within the thickener.
Extrapolation to zero volume determined the operating period for the
day. Comparison of the values obtained in this manner with available
records indicated that the procedure was reasonably accurate in
predicting operating periods. Table 2 operating periods were obtained
in this manner.
Flows and loadings on Table 2 were obtained by utilizing the
hydraulic and mass balance relationships shown on Table 1 together with
the measured solids concentrations of the respective process streams.
Coagulant Requirements
When the flocculation system was in operation, a simulated bench
scale system was employed to determine the optimum coagulant
concentration. The resulting coagulant dosage was then compared with
that obtained employing the traditional jar test procedure to determine
what differences, if any, existed between the two techniques.
Figures 5 through 7 illustrate the principle features of the bench
scale apparatus, or "calibrator". Figure 5 illustrates the portion of
the calibrator simulating the Flocculator/Concentrators. It will be
noted that the process stream in this portion of the system has a
definite separation of solids in the lower portion of the coil flow.
This separated two-phase flow was then introduced into a flow dividing
tee as shown on Figure 6 in which the high solids concentration portion
was separated from the clear water. The high solids concentration
stream was then introduced into a bench scale solids thickener (Figure
7). Performance of the bench scale apparatus was observed and adjusted
to an efficient operating point. This dosage was then utilized in the
full scale flocculation system.
Figure 8 illustrates the results of jar tests run during the
September 20 day of operation. The coagulant dosage for the water
recycle system was significantly less than that for the conventional bin
dump system when water recycle was not being practiced. This was
apparently due to the presence of a singificant settleable solids
fraction in the bin dump waters under these circumstances. As
indicated, with the water recycle system operating, the optimum
246
-------
200
20 SEPT. '74
16 OPERATING HRS.
to
*>•
-q
O
O
O
100
0«
27 SEPT. '74
7 OPERATING HRS.
12 18
CLOCK TIME {HRS )
0
Figure 4. Cummulative thickener underflow volumes.
-------
Figure 5. Bench scale Flocculator/Concentrator.
248
-------
to
J--
Figure 6. Flow splitting tee.
-------
Figure 7. Bench scale thickener.
250
-------
to
01
.25
.20-
o
<
DC
o
5
Z3
UJ
.15-
.10-
.05-
9:35 AM
i
5
8:30 AM (DISC CLEANER) w/WATER RECYCLE
8:00 AM
(CONVENTIONAL SYSTEM)
20 25 30 30
10 15
COAGULANT DOSE, ml/200 ml, (1 ml/200 ml -12.5 mg/l)
Figure 8. Jar test results - September 20, 1974.
-------
coagulant dosage varied from 20 to 50 milligrams per liter. Similar
concentrations were found optimal for the bench scale calibrator.
DISCUSSION
Experimental Results
Table 3 summarizes the results of the hydraulic and mass balances
discussed. The first two days of operation which were investigated were
the 13th and 17th of September. On the 13th of September as indicated
on Table 3, the swirl solids concentrator factor was approximately
unity, indicating relatively little settleable solids in the bin dump
waters. This fact was confirmed by grab samples taken on that day which
indicated very little if any settling within a 30-second period. The
thickener solids underflow concentration was correspondingly low. In
spite of the suspended solids, the thickener removal efficiency was a
reasonable 81 percent. Overall system solids removal was 22 percent for
that day, indicating the approximate fraction of settleable solids in
the bin dump waters. On the 17th of September, the bin dump waters
contained appreciably more settleable solids as evidenced by the swirl
solids concentrator factor. Thickener underflow solids concentration
was correspondingly doubled. In spite of the increase in the fraction
of settleable solids, there was relatively little change in the
thickener solids removal efficiency and the overall system solids
removal efficiency.
September 20 was the first full day of operation with the
flocculation system. As indicated by the swirl solids concentrator
factor, this day was also characterized by significant quantity of
settleable solids in the bin dump waters. The thickener underflow
solids concentration, however, increased disproportionately and can only
be explained by the effect of the addition of the coagulated solids to
the thickener. The residual solids in the thickener overflow were
dramatically reduced on this day with overall system removal
efficiencies significantly higher than any experienced up to that time.
The next reasonably long operating period of the flocculation
system occurred on the 27th of September with a reasonably large swirl
solids concentrator factor. In comparing the thickener underflow solids
concentration of the 27th of September with the 17th of September, some
appreciation can be gained for the effect of the addition of coagulated
solids to the thickener in increasing the solids underflow
concentration. The thickener solids removal efficiency was still
significantly higher than that when the system was operated without
252
-------
Table 3. PERFORMANCE SUMMARY
Date
Without
flocculation
13 Sep
17 Sep
With
flocculation
20 Sep
27 Sep
Swirl
solids
concentrator
factor
1.0
2.3
3.4
1.9
Thickener
underflow
solids,
9/1
60.0
120.9
417.9
346.4
Thickener
solids
removal ,
%
81
86
99
95
Overall
solids
removal ,
%
22
33
78
54
253
-------
flocculation. The overall system solids removal efficiency was 54
percent.
Figure 9 is a plot of the thickener performance as measured by the
underflow solids concentration and the solids removal efficiency as a
function of the swirl solids concentrator factor. On the basis of the
limited data analyzed, it appears that the thickener underflow solids
concentration is increased by approximately 250 grams per liter when the
flocculation system was employed. Residual solids in the thickener
overflow are reduced 3 to 4 times with the flocculation system
operating. For- effective solids removal and efficient water
reclamation, the water recycle system must be operated with the
flocculation system and flows of uncoagulated material to the thickener
should be excluded.
254
-------
CK
(/I
Q
O
on
UJ
UJ
o
:n
100
90
70
WITH FLOCCULATION
WITHOUT FLOCCULATION
500
400-
300
WITH FLOCCULATION-
A-
O
200-
.©
•WITHOUT FLOCCULATION
3.0
SWIRL SOLIDS CONCENTRATOR FACTOR
Figure 9. Thickener performance correlation.
255
-------
MEATPACKING WASTEWATER TREATMENT BY SPRAY RUNOFF IRRIGATION
Jack L. Witherow*
Mickey L. Rowe**
Jimmie L. Kingery***
INTRODUCTION
Spray runoff irrigation is a treatment process in which wastewater
is applied to sloping, plant covered land. The process yields a treated
effluent which is collected on the toe of the slope for discharge. The
process is also referred to as an overland flow system or a living
filter. Utilization of the system is dependent upon such variables as
available land, soil type, topography, climate, location, and wastewater
characteristics. Vegetable processing plants using this process require
a land area of about 100 acres per million gallons per day.1 Clay type
soils are needed to control infiltration and to promote runoff. Also
necessary is a surface with a 2 to 6 percent slope which is smooth
enough to prevent pooling or channelization of flow.
While spray runoff irrigation has many advantages, there are
inherent problems to be overcome. Solids and grease in the wastewater
may build up deposits under the spray pattern and result in anaerobic
conditions. The potential for odors, insects, and aerosol drift
restricts locating this treatment process near residential areas.
Precipitation and freezing temperatures limit wastewater application;
however, this can be overcome through use of storage facilities.
This report presents a study on a pilot scale spray runoff
irrigation system. The objectives of the study were: (1) to determine
industrial Environmental Research Laboratory, US Environmental
Protection Agency, Corvallis Field Station.
**School of Environmental Science, East Central State University, Ada,
Oklahoma.
***Robert S. Kerr Environmental Research Laboratory, US Environmental
Protection Agency, Ada, Oklahoma.
256
-------
if the system would sufficiently treat meatpacking wastewaters to meet
national discharge limitations, (2) to ascertain whether a goal of 80
percent removal of both total nitrogen and phosphorus could be achieved
to meet future environmental needs, and (3) to establish the economic
feasibility of the system.
EXPERIMENTAL DESIGN
A previous study2 had shown that a meatpacking waste which had
received treatment in an anaerobic lagoon could be treated by spray
runoff irrigation to meet average discharge limits for 1977. (At the
time of the study maximum daily limits had not been proposed.) However,
use of an anaerobic lagoon prior to spray irrigation can create a
nuisance. Protein and sulfates in the wastewater will be reduced in the
lagoon to ammonia and hydrogen sulfide, respectively. These will be
released to the atmosphere by the spraying action. This potential
problem may be eliminated and the system design may be simplified by
using raw meatpacking wastewater in the irrigation process.
Spray runoff irrigation of meatpacking wastewater was studied for
six months in a pilot plant at the W. E. Reeves Packinghouse in Ada,
Oklahoma (Figure 1). Application of the waste began in January and
ended in June, allowing evaluation under both cold and warm weather
conditions. The raw wastewater was diverted from a manhole several
minutes each hour to obtain the limited quantity needed and to composite
a wastewater representative of the plants daily flow. The wastewater
passed through a hydrosieve with a 0.020-inch slot openings and was
stored in a 2,100 gallon tank (Figure 2). The hydrosieve was used for
removal of solids which would clog the spray nozzles. The storage tank
was used to equalize flow and to give a positive pressure on the pump
inlet. The storage tank was aerated to prevent anaerobic conditions and
solid-liquid separation.
Each of the three 0.1 acre irrigation plots were 33 feet by 115
feet. The site for the plots had 3 to 12 inches of soil over
conglomerate rock. A clay loam soil was added to form a smooth surface
with a 6 percent slope. The increased soil depth ranged from 1 to 4
feet. A native bermuda grass was grown on the plots to provide a deep
mat for bacterial growth and erosion control. A berm was placed on the
upper end of the plots to divert rainfall runoff. Aluminum stripping
was placed around each plot to direct the spray runoff through an outlet
structure where flow was measured by a tripping bucket and counter
arrangement.
257
-------
to
Oi
co
Raw wastewater
.sample point
IRRIGATION PLOTS
Automated
valve
STORAGE
TANK
Sample
.point
STATIONARY
SCREEN
Manhole Air
, A-
/ Spray
/ r>/ym/7.?
Automated
valves
pumps
>\
*
Flow measurement
8t Sample points
Figure 1. Spray runoff irrigation pilot plant.
-------
Figure 2. Hydrosieve and aerated storage tank.
259
; EPA Headquarters Library
Mail code 3404T
Pennsylvania Avenue NW
•ninoton, DC 20460
90?-566-0556
-------
Because revolving irrigation guns were not successful on these
small plots, revolving booms with nozzles at the ends were used to
provide even distribution of flow across the plot (Figure 3). The
radius of the spray pattern was adjusted to remain within the 33 foot
width. Health hazards from aerosol drift due to high pressure
application had caused Tarquin et al.3 to also use low pressure booms.
Constant speed positive displacement pumps were used to apply and
measure the flow to the three soil plots. These pumps were operated up
to 55 hours per week during the regular hours of plant operation. The
flow per minute for each plot was measured by catching the nozzle
discharge, and application rates were established by controlling the
time each pump was operated per day.
Weekly samples were taken of the raw wastewater, of the screened
and aerated wastewater applied to the soil plots and of the effluent
from each plot. Automatic composite samples were taken of the raw
wastewater and wastewater applied to the plots. Grab samples were taken
of the three plot effluents. Previous experience with this process had
shown that grab samples of these effluents were satisfactory.1* The
automatic samplers were activated to take four samples per hour during
the slaughtering and/or processing operations in the packinghouse.
Samples were time composited in iced containers. Collected samples were
stored at 4 degrees C in the laboratory.
The weekly samples were analyzed for five-day biochemical oxygen
demand (BOD5), chemical oxygen demand (COD), pH, total solids (TS),
total volatile solids (TVS), total suspended solids (TSS), ammonia (NH3-
N), nitrite plus nitrate (N02+N03-N), total Kjeldahl nitrogen (TKN) and
total phosphate (T-P). In situ measurements were made for temperature
and dissolved oxygen (DO) during sample collection. Once a month
specially collected samples were analyzed for oil and grease (FOG),
sett!cable solids and fecal coliforms.
All analyses were made in accord with EPA Methods for Chemical
Analysis of_ Water and Wastes, 1971. The cfiemical analyses were
subjected to quality control procedures. Duplicate analyses were run on
10 percent or more of the samples. The sum of the squared differences
was plotted on a quality control chart for each analysis. When the
difference was outside of the established boundaries, the samples were
analyzed again. Standards were also run on most analyses. In the
middle of the study period, two sets of unknown reference samples were
analyzed for BOD5, COD, NH3-N. TKN and T-P. All results were within one
standard deviation of the true value.
260
-------
Figure 3. Distribution system and irrigation plots.
261
-------
Sampling Accuracy
Solids-laden waste streams are difficult to sample. For this
reason, an automatic sampler which dipped a container below the surface
was selected for sampling the raw wastewater. It was hoped this sampler
would eliminate the plugging and straining problems caused by small
pumps and small diameter lines used in most samplers. The sampling
location was designed to create turbulance for solids mixing and
elimination of solids deposits. Harris and Keffer5 have compared types
of automatic samples and found vacuum samplers with high intake
velocities obtain higher concentrations of parameters influenced by
solids. On two occasions, dual samples were taken—one by the
automatic dip sampler; the other by an automatic vacuum actuated
sampler. All samples were time composited. The routine analysis on
both samples showed the vacuum samples to be about 20 percent higher for
BOD5, COD, TS, TVS, TSS and about 20 percent lower for TKN tnan the
dip samples. The automatic dip sampler apparently missed 20 percent of
the solids in the waste stream.
An automatic sampler containing a centrifugal pump was used for
sampling the screened and stored wastewater. The sampler was installed
on the intake line to the spray pumps. To obtain representative solids
levels, samples were only collected when the spray pumps were operating.
To obtain a sample for comparison^ an open container was placed under
the spray pattern on one of the plots. Both samples were time
composited. A comparison of the analyses revealed the pumped sample to
be about 25 percent lower in COD, TS, TVS, and TSS, but about 75 percent
higher in NHs-N than the waste collected as it fell to the soil plot.
Apparently the automatic sampler did not obtain all solids that had
passed through the 0.02-inch screen openings and the spraying action
scrubbed a significant amount of ammonia from the wastewater.
EXPERIMENTAL RESULTS
Screening and Storage
The passing of the raw wastewater through a 0.020-inch slot opening
in a tangential screen and the aerated storage in a 2,100 gallon tank
resulted in significant reduction in the waste strength. The
concentrations and removals shown in Table 1 are based on mean values.
The concentrations of BODs, COD and TSS may be 20 to 25 percent low
because of automated raw waste sampling. Additional statistical data on
the influent and effluent are in the Appendix.
262
-------
Table 1. EFFECTS OF SCREENING AND STORAGE
Items
BOD 5
COD
TSS
FOG
Influent,
mg/1
634
1,675
499
139
Effluent,
mg/1
374
936
219
67
Removal ,
%
41
44
57
52
263
-------
The screen served the intended purpose of removing the large soilds
and preventing plugging of the spray nozzles. Screens offer the
advantage of removing solids (bone, hair, toenails and plastics) that
would not be treated by the irrigation process. The pilot scale
operation made the disposal of the screen solids a minor task. In a
large operation, mechanized solids handling equipment would be needed.
Part of the raw waste flow was diverted from the packinghouse sewer
a few minutes each hour by means of an automated valve. With this
intermittent diversion, the storage tank was necessary for continual
application to the spray plots. Air was introduced through a header at
the bottom of the tank to mix the contents and to maintain aerobic
conditions. The dissolved oxygen in the tank liquid averaged 0.8
milligrams per liter. The liquid detention time in the tank was
calculated as averaging less than six hours, but liquid remained in the
tank overnight. The tank was drained and flushed weekly to remove minor
sludge deposits. Reduction of protein in these deposits is suspected as
the cause of the average increase of 18 milligrams per liter of NH3-N.
In a full-scale operation, increase in ammonia could be minimized by
standard wet well designs.
Loading on the Plots
The flow applications were initially set to increase phosphorus
removal. The concept was to increase the liquid detention by applying
the flow intermittently. The pumps and nozzles would deliver 0.07
inches per hour, but the flows to Plots 5, 6 and 7 were only applied 40,
30 and 20 minutes per hour, respectively. After two months of
operation, it was concluded that this on-off application was not
successful in increasing phosphorus removal. The emphasis was shifted
to minimizing NH3-N and N02+N03-N in the discharge. Minimum
concentrations of these parameters were being obtained on Plot 5. To
bracket the loading on this plot the application on Plot 7 was increased
to 50 minutes per hour in mid-March. In mid-May, a period of high
evaporation eliminated the surface discharges from Plots 5 and 6. To
gain additional information, the application to Plot 6 was increased by
running the pump continually 10 hours per day. The average flows
applied to Plots 5, 6 and 7 during the study are given in Table 2.
Since the wastewater was applied to the three plots, the organic
and nutrient loadings are directly proportional to the hydraulic
loadings. The loading of BOD5, COD, TSS, NH3-N, T-N and T-P in pounds
per acre per day are shown in Table 3. The nitrogen loading is
important because a few states put limitations on this nutrient to
protect ground water supplies. The wastewater had a ratio of BOD5:N:P
264
-------
Table 2. LOADING ON IRRIGATION PLOTS
(mean values)
Items
Flow
BODS
COD
TSS
NH3-N
T-N
T-P
Units
gal/ac/day
Ib/ac/day
1 b/ac/day
1 b/ac/day
1 b/ac/day
1 b/ac/day
1 b/ac/day
(Operation in
weeks)
Plot 5
10,490
32.7
79.3
17.8
2.8
9.4
0.6
21
Plot 6a
9,050
29.5
73.2
14.3
2.1
8.2
0.5
15
Plot 6b
16,610
47.7
97.1
30.5
5.8
14.6
0.9
6
Plot 7a
6,560
21.8
52.8
8.7
1.1
5.0
0.5
8
Plot 7b
14,800
45.0
106.2
28.0
4.9
14.2
0.7
14
265
-------
Table 3. DISCHARGE FROM IRRIGATION PLOTS
OJ
Items
Flow
BOD 5
COD
TSS
NH3-N
T-N
T-P
Temp.
BOD5
COD
TVS
TSS
NH3-N
T-P
Units
gal/ac/day
Ib/ac/day
1 b/ac/day
1 b/ac/day
1 b/ac/day
1 b/ac/day
1 b/ac/day
°C
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
Plot 5
2,510.
0.41
4.21
1.04
0.04
0.35
0.17
17.2
10.0
123.
270.
25.
1.2
6.7
Plot 6a
3,190.
0.38
5.09
0.73
0.02
0.53
0.23
15.4
5.8
107.
233.
23
0.5
5.9
Plot 6b
1,120.
0.06
1.06
0.21
0.00
0.03
0.07
27.4
5.2
103.
179.
17.
0.0
6.9
Plot 7a
1,150.
0.06
0.94
0.15
0.00
0.15
0.06
13.8
6.0
103.
271.
17.
0.6
6.5
Plot 7b
4,570.
0.75
5.25
1.12
0.04
0.14
0.21
22.9
10.1
132.
215.
26.
0.5
6.4
-------
of 100:30:2, which is satisfactory for biological treatment processes.
Additional data on loadings and concentrations are in the Appendix.
Discharge from the Plots
Removal efficiencies based on both concentrations and pounds of
pollutants were calculated from the data in Tables 2 and 3 and the
Appendix. Removal efficiencies were 90 percent or greater for all
plots; exceptions were pounds of phosphorus and milligrams per liter of
COD, TVS, and T-P. The percentages are not presented because, with one
exception, they did not show any meaningful differences among plots.
The exception was the pounds of phosphorus removed. This difference was
the result of increased water loss during warm weather. Removal of
phosphorus on the basis of concentration was similar among plots and
less than 10 percent. However, average flow losses across the plots
varied from 65 to 97 percent of that applied.
The average conditions given in Table 3 show all the plots to
discharge low concentrations of pollutants and show minor changes in
concentration among plots. The variation in hydraulic and organic
loading conditions tested had little effect on removals. Two factors
which mask the differences that occurred were the effects of the weather
and the averaging of extremes. The weather caused these extreme
conditions and was the singularly most significant factor in affecting
discharge loads under the test conditions."
The loadings and weather conditions of Plots 6b and 7a were the
most widely different; yet the discharges were remarkably similar.
There was no meaningful difference in removal efficiencies based on
pound of pollutants and, except for TVS, the concentration of the two
discharges appeared identical. A statistical test showed no significant
difference between the TVS means. Thus, a loading of 16,600 gallons per
acre per day in the summer and a loading of 6,500 gallons per acre per
day in the winter resulted in the same average volume and mass of
pollutants in the discharges. The data on Plot 6b was collected in
January, February, and March, and the data on Plot 7a was collected in
May and June. The respective pan evaporation for these two periods
averaged 3.5 inches per month and 9.0 inches per month.
A comparison of effluents from Plot 6 for a period of six weeks in
April and May at a hydraulic loading of 9,000 gallons per acre per day
with the following six weeks in May and June at^.a hydraulic loading of
16,500 gallons per acre per day showed little or no difference in
concentration of pollutants. Almost doubling the hydraulic loading did
not result in a noticeable decrease in removal based on concentration
during these two warm periods.
267
-------
Waste load discharges can best be controlled by matching hydraulic
loadings with weather conditions to limit discharge volumes.
Rainfall Effects
Rainfall on wastewater irrigation plots can significantly increase
the waste loads discharged in the runoff. Rainfall increases the volume
of runoff and may increase the concentration of some pollutants in the
discharge. Law et al." evaluated the effect of rainfall by continuous
measurement of electrical conductivity. They found that rainfall of 0.1
inch or less did not contribute enough volume to alter the composition
of the runoff contributed by the applied wastewater. Rainfall events of
0.1 to 2.0 inches had a marked effect by steadily decreasing the
conductivity with increasing amounts of rainfall. Rainfall events
greater than 2.0 inches caused little additional reduction in
conductivity. This information does not include runoff flow
measurements and waste loads cannot be calculated. The information does
indicate that waste load discharged are increased by rainfall events
greater than 2.0 inches.
During this investigation, routine sampling occurred on three days
when rainfall was part of the grab sample of the effluent. The rainfall
intensity at the time of sampling was not measured, but the rainfalls
ranged from 0.7 to 1.5 inches per day. In two of these three events the
runoff volume exceeded that of the applied wastewaters. In these two
events the pounds of phosphorus discharged were greater than that
applied and the suspended solids discharged exceeded the maximum day
limit in the Best Available Treatment (BAT) standards. In one event the
BOD5 discharged also exceeded the BAT daily limit. To specifically
measure the effects of rainfall, composite samples of the runoff from
the plots were taken during five rainfall events, outside of the routine
sampling schedule. These samples were analyzed for TS, TVS, TSS and T-
P. Total solids concentrations in the discharge samples taken during
rainfall were considerably less than during non-rainfall periods. This
is in agreement with the conductivity data reported by Law.1* The over
15,00 milligrams per liter difference in TSS between the wastewater and
rainfall can account for these decreases by dilution. Total volatile
solids and total phosphorus did not differ significantly in
concentration; however, suspended solids were usually higher and in one
case the concentration was 10 times that of the previous sample taken
during dry weather. Flow recordings were not taken during these
rainfall events and pounds of TSS discharged cannot be computed. During
rainfall, the discharge flow is certain to increase over dry weather
discharges. During periods when wastewater is applied, rainfalls of
greater than 0.7 inches per day can increase waste concentrations as
268
-------
much as 10 times average discharge values and maximum daily limits in
the BAT standards can be exceeded.
A discharge volume was measured and sampled during a rainstorm when
wastewater was not being applied. A rainfall of 0.62 inches was
measured at the local weather station. The runoff from the plot was 230
gallons per acre. The concentrations of TVS and TSS were 240 milligrams
per liter and 11 milligrams per liter, respectively, which were similar
to discharge concentrations the next day when wastewater was applied and
there was no rainfall. The rainfall runoff from the plot had a TS of
634 milligrams per liter, about half that in the next days sample.
Rainfall on the irrigation plots can also result in a waste load
discharge between periods when wastewaters are applied.
Effects of Temperature
Water temperature was measured at each sample point at the time
samples were collected and minimum and maximum daily air temperatures
were obtained from the local weather station. The two sources of heat
were the plant's hot water system and the ambient conditions. The
ambient conditions, as defined by air temperatures, were dominant and
from January into April usually reduced the wastewater temperature as it
passed through the collection and treatment systems. In late April, May
and June, ambient conditions usually maintained a stable wastewater
temperature through these systems.
Because the effect of temperature on biological treatment is well
established, the study period was selected to encompass both cold and
warm weather conditions. A statistical analysis was made to determine
the correlation between effluent temperatures and concentrations of
BOD5, COD, NH3-N, N02+N03-N and T-P for Plots 5, 6a and 7b. The
analyses were made on effluent concentration rather than on change in
concentration or removal efficiencies. These latter items were mainly
controlled by the influent concentration, and temperature and influent
characteristics are not usually related. The analyses gave no
significant correlations between the parameters and temperature except
for NOa+NOs-N. On both Plots 5 and 6a, a correlation coefficient of
-0.71 was obtained. The average temperatures and average NOz+NOs-N
levels for the three plots shown the same negative correlation.
Averages Plot 6a Plot 5 Plot 7b
Temperature, degrees C 15.8 18.2 25.6
N02+N03-N, milligrams
per liter 10.« 4.6 0.5
269
-------
The correlation for Plot 7b was not statistically significant, but the
low concentration of N02+N03-N was meaningful. On the three plots, the
effluent concentrations of NH3-N and T-N were related to temperature.
After mid-April the effluent temperatures remained above 20 degrees C at
which time NH3-N concentration dropped to zero and remained there
throughout the rest of the study period. Total nitrogen concentration
dropped significantly at this time and remained below 6.2 milligrams per
liter.
Reduction of protein nitrogen to ammonia in the storage tank was
affected by temperature. The screened wastewater was held for several
hours in a tank prior to spraying on the plots. The concentration of
NH3-N and the temperature had a correlation coefficient of 0.65.
Ammonia concentration consistently increased in the tank, but the
increases were greatest after mid-April. Other forms of nitrogen did
not noticeably change after mid-April in this waste stream applied to
the three plots.
Removal of all forms of nitrogen on the soil plots was affected by
temperatures. Maximum reduction occurred after water temperature
reached 20 degrees C. The apparent causes were: the increased
concentration of NH3-N and its loss to the atmosphere by spraying; a
reduction of N02+N03-N by denitrification, and nitrogen uptake by
increased microbial and plant growth. Because of the impermeable rock
layer below the soil plots, loss of nitrogen into a ground water supply
was not possible.
Temperature had an effect on the discharge volume. The most
notable effect was when a surface discharge did not occur on hot days
when ambient conditions maintained high water temperatures. The absence
of a discharge was noted at 9,000 gallons per acre per day with an
influent temperature of 19 degrees C and at 10,500 gallons per acre per
day with an influent temperature of 25 degrees C. However, a discharge
continued at 15,000 gallons per acre per day with effluent temperatures
of 30 degrees C. In addition to temperature, wind noticeably influenced
the discharge volumes. A prolonged period of freezing temperatures
sufficient to stop the discharge because of ice formation did not occur
during the study period.
NATIONAL EFFLUENT LIMITATIONS
The effluent limits, for the category "low packinghouse" given in
Table 4 are maximum values for an average of daily values within 30
consecutive days or for any one day. All of the treatment systems meet
the Best Practicable Treatment (BPT) limits in Table 4 which must be met
270
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Table 4. COMPARISON OF TREATED WASTEWATERS AND EFFLUENT LIMITATIONS
(lb/1,000 Ib LWK)
Treatment systems
Plot 5
Plot 6a
Plot 6b
Plot 7a
Plot 7b
Effluent limitations
Best Practical Treatment
Best Available Treatment
BOD s
30 day
0.01
0.02
< 0.01
< 0.01
0.02
0.17
0.04
1 day
0.14
0.19
<0.01
0.01
0.29
0.34
0.08
TSS
30 day
0.05
0.06
<0.01
0.01
0.04
0.24
0.06
1 day
0.48
0.34
0.02
0.02
0.40
0.48
0.12
271
-------
by July 1, 1977. Plots 6b and 7a meet the Best Available Treatment
(BAT) limits in Table 4. The BAT limits must be met by July 1, 1983.
In all cases, the BAT limits which were exceeded were maximum day
limits. The difference between average discharges and maximum day
discharges were ten-fold rather than double.
All maximum day values which exceeded the BAT limits in Table 4
occurred on two sample days when heavy rainfall occurred. On March 20,
1974, a rainfall of 0.71 inches was so intense that the flow measuring
devices were unable to record all the discharge. On this day, the waste
load discharge from all plots exceeded both the BOD5 and TSS limits. A
heavy rainfall did not occur when samples were collected from Plots 6b
and 7a.
All averages calculated for 30-day periods consisted of four or
less data points. Except for that period which included March 20, 1974
data, these values meet the BAT limits in Table 4. To obtain a better
estimate of the mean, the treatment system 30-day values in Table 4 are
averages for entire study periods.
In addition to the parameters in Table 4, there are limits on oil
and grease, ammonia, pH, and fecal coliforms. The oil and grease
concentrations in the effluents from the plots were in most cases less
than 5 milligrams per liter, the limit of accuracy of the analytical
method. The maximum value was 8.6 milligrams per liter. Ammonia
concentration averages ranged from 0.0 to 4.8 milligrams per liter and
maximum values ranged from 0.0 to 7.5 milligrams per liter in the
effluents from the plots. The pH levels ranged from 7.5 to 8.5 in the
effluents. Additional data on these parameters are in the Appendix.
Oil and grease, ammonia, and pH levels in the discharges meet both BPT
and BAT limits. The fecal coliform requirement for both limitations is
a maximum of 400 mpn (most probable number) per 100 milliliters.
Maximum fecal coliform ranged from 8,000 to 320,000 mpn per 100
milliliters in the discharges from the plots. The addition of
disinfection facilities will enable the treatment systems to meet this
limit.
DISCUSSION
These pilot investigations pointed out needed additions to the
treatment system to meet BPT or BAT limitations. Disinfection is needed
to meet the fecal coliform requirement in both limitations.
Disinfection with chlorine is most economical with a chlorine contact
basin having about 1/2 hour detention. To meet BAT limits, the system
also needs a means to control maximum daily discharge loads.
272
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During two intense rainfalls when wastewaters were being applied,
daily discharges in pounds of BOD and TSS were measured at ten times the
average conditions and at five times the the maximum daily limit. The
increase in TSS caused the increase in BOD. The suspended solid limit
was exceeded when the BOD limit was not exceeded. During these two
rainfalls both volume and concentrations increased two- to five-fold
over average conditions. During other rainstorms, however, discharge
volumes were increased two- to five-fold over the average, but
concentrations did not increase and the daily maximum limits were not
exceeded. Although both volume and TSS concentration increased before
the daily limits were exceeded, either or both can be controlled to meet
the BAT limits.
There are a number of liquid-solid separation processes that can be
used to reduce suspended solids. Most of these are physical-chemical
processes which are mechanically complicated and expensive. Slow sand
filtration is a simple process which might be employed. Its area
requirements would be a 2 to 5 percent increase over that for the spray
runoff plots. The spray runoff system can obtain 80 to 90 percent
suspended solids removal and is already available. Since raw wastewater
would be sprayed during periods of plant operation, the irrigation
system would be available at night and during weekends. However,
storage facilities would be needed to use it during these periods.
Storage facilities offer several advantages. They can be designed
with a maximum release to meet daily discharge limits. Reduction of
suspended solids will occur through sedimentation. When concentrations
of pollutants need additional reduction, part of the stored volume can
be recycled. Storage facilities can be incorporated in the runoff
collection system or can be created by damming natural depressions in
the drainage system. Additional storage volume for chlorination can be
incorporated at minimum cost. However, the permanent pool should be
minimized to prevent algal growth. The storage facilities, like the
irrigation plots, should be protected by diversion dikes from rainfall
runoff from upslope areas.
The storage requirement would be dependent upon rainfall and
temperature conditions and would vary from a few hours to several days.
The storage volume would be controlled by the rainstorm selected for
design. The data collected in this investigation were insufficient to
determine the rainstorm which would result in the maximum waste load
discharge. However, indications were that it would be a rainstorm over
0.7 inches. Storage of several times the runoff from a 0.7-inch rain
would be a minor part of the total cost of the system.
For meatpackers in the northern part of the country, spraying of
wastewater on land during extended periods of freezing weather would be
273
-------
physically impractical. Use of_ the runoff irrigation system would
require storage during these periods.
Use of storage to control maximum daily discharges during heavy
rainfalls and to stop application during extended periods of freezing
weather suggests the potential for storage and flow equalization of the
concentrated raw wastewater. Such storage could result in an anaerobic
lagoon. The anaerobic lagoon, which can obtain over 80 percent BOD
removal, is the most cost effective treatment process available to the
meat industry.
The evaluation of treatment in an anaerobic lagoon followed by
spray runoff irrigation was reported on previously.1 This investigation
was carried out at these same facilities over a six month period ending
in April 1972. Anaerobic effluent was applied at 8,200 gallons per acre
per day which is within the range of hydraulic loadings used in this
study. The BOD5 loading was an order of magnitude less at 4.6 pounds
per acre per day, but the NHs-N and T-P loadings were nearly double at
4.9 and 1.1 pounds per acre per day, respectively. The runoff during
the fall and winter study period averaged 56 percent of that applied.
Removal efficiencies of both BODs and TSS were in excess of 95 percent.
Phosphorus removal was mainly dependent upon loss of flow.
A disadvantage of this sytem was the discharge of NHa-N which
averaged 20 milligrams per liter and exceeded 10 milligrams per liter in
85 percent of the observations. This was due to the high NHs-N
concentration in the anaerobic lagoon effluent which averaged 74
milligrams per liter. The anaerobic lagoon converts most of the protein
in meat packing wastewaters to anmonia. Thus, where ammonia limits
exist, such as in BAT standards, storage in an anerobic system is not
advisable. In mild climates, storage facilities following the spray
runoff irrigation system would eliminate the changes of anaerobic
conditions and the resulting increase in ammonia. When storage of
concentrated wastewater is required by cold weather, the wastewater can
be kept aerobic by injection of air at the bottom of the storage
facilities. Additional investigation of the spray runoff treatment
system is needed to evaluate storage and application techniques.
Cost Estimates
The design and operational information developed in these pilot
scale studies was used to make an estimate of cost. A number of
assumptions were necessary; those most influencing costs were land
prices, operational manpower, power requirements, repairs, and capital
recovery. The costs were calculated for a system capable of treating
274
-------
100,000 gallons per day. A medium size meat packing plant would have a
flow of this magnitude or larger.
The screens were selected to handle 175 gallons per minute. The
wet well was sized to equalize the output at 100 gallons per minute.
Three pumps each with a capacity of 50 gallons per minute were selected.
The irrigation system was based on cost for similar systems used for
crop production. Material quantities were determined from a layout
sketch. Costs for pipe, automated valve, pumps, timers, and
chlorination equipment were from catalogs and manufacturer quotes. The
discharge storage facilities were sized for a 3-inch rainstorm and the
recycle pump and line were sized for 50 gallons per minute. Recycle
pumping costs were based on 30 inches of rainfall.
The land requirement was based on a winter application of 6,500
gallons per day per acre. Land cost with clearing and grading was
assumed at $1,000 per acre. Land and storage pond cost were amortized
at 8 percent over 20 years. Equipment and structures were amortized at
8 percent over 10 years. Manpower estimates were based on 1 hour per
day or per rainstorm and at $3.75 per hour. Thirty rainstorms per year
were used. Electric power was estimated at 3£ per KWH and was
sufficient for pumping the wastewater and recycled flow against a 100
foot head. Chlorine was priced at $13.50 per hundredweight (cwt).
Repairs plus taxes were estimated at 4.5 percent of capital cost per
year. Table 5 shows a summary of the estimated costs.
Crites et al.1 have reported capital costs for clearing of land,
grading of "slopes, planting and construction of the distribution system
at $1,006 and $1,500 per acre for two overland flow systems. Operating
costs for these two systems range from 5<£ to 10<£ per 1,000 gallons.
Land costs for eight other spray irrigation treatment systems ranged
from $110 to $800 per acre.
Economic feasibility, especially for the small to medium
packinghouse, is controlled by the cost of technical personnel for
operation. Thus the limited mechanical equipment and automated
operation of this process offer special advantages to these plants.
CONCLUSIONS
The restraints of the variables tested and of the test conditions
necessarily qualify the following conclusions:
275
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Table 5. ANNUAL CAPITAL AND OPERATING COST ESTIMATES
Item
Land or storage pond
Equipment & structures
ANNUAL CAPITAL COST
Manpower
Electric power
Chlorine
Repairs & taxes
ANNUAL OPERATION COST
Annual Capital & Operating
$/l,000 gallons treated
Screening, spray
irrigation &
chlori nation
$1,530
2,205
$3,735
$ 975
400
90
1,350
$2,845
$6,580
$0.25
Storage &
recycl e
$205
298
$503
$112
75
-
180
$367
$870
$0.03
276
-------
1. Treatment of meat packing wastewaters by screening, spray
runoff irrigation, and disinfection can meet 1977 National
discharge limitations.
2. Treatment of meatpacking wastewaters by screening, spray runoff
irrigation, and disinfection can meet 30-day average limits in
the 1983 National discharge limitations. Maximum daily limits
for BOD5 and suspended solids are exceeded when intense
rainfall results in large increases in the discharge volume and
concentration of suspended solids.
3. The spray runoff irrigation system removed over 90 percent of
the total nitrogen applied and discharged an effluent with a
maximum ammonia concentration of 4.5 milligrams per liter. In
the discharge, nitrate plus nitrite concentrations and
temperatures had a significant correlation. Concentrations of
all forms of nitrogen discharged noticeably decreased when
effluent temperatures were 20 degrees C or more.
4. The spray runoff irrigation system removed between 60 and 90
percent of the quantity of phosphorus applied. Removal was
equal to the water lost to seepage and evaporation. Phosphorus
concentrations decreased less than 10 percent.
5. The hydraulic and organic loadings had minor effects on
removals.
6. Waste load discharges can be controlled by matching hydraulic
loadings with weather conditions. For example: loadings of
16,600 gallons per acre per day in the summer and 6,500 gallons
per acre per day in the winter resulted in the same waste load
discharges which meet 1983 limits for BODs and suspended
solids. During hot weather loadings of 9,000 gallons per acre
per day with water temperature at 19 degrees C or of 10,500
gallons per acre per day with water temperature at 25 degrees C
resulted in no surface discharge.
7. During periods when wastewaters are applied, rainfalls greater
than 0.7 inches per day can increase the waste load discharge
to as much as ten times average conditions, exceeding the
maximum daily value in the 1983 National discharge limitations.
Between periods of wastewater application, rainfall can result
in a waste discharge from the irrigation plots.
8. Control of the discharge in respect to volume and/or suspended
solids concentration is necessary during intense rainfall to
meet maximum daily limits in the 1983 National discharge
277
-------
limitations. Temporary storage facilities with a controlled
discharge, and facilities for partial recycle to the irrigation
area could offer this control at minimum cost.
Cost estimates for a 0.1 million gallons per day plant
including screens, wet well, spray runoff irrigation and
chlorination were made from the design developed in this pilot
scale study. Capital costs, including land, were $30,000.
Annual capital and operating costs were $0.25 per 1,000 gallons
treated. The addition of a storage and recycle system would
increase capital costs by $4,000, and annual capital and
operating costs by $0.03 per 1,000 gallons.
RECOMMENDATIONS
A full-scale system on the design and operation developed in this
pilot scale study should be demonstrated in a warm climate. The system
should include screens, spray runoff irrigation, and chlorination,
followed by an auxiliary storage and recycling system to control
discharges during rainstorms.
Further development of design and operation of this system should
be undertaken in other parts of the country where extended freezing
periods occur. The system should include screens, spray irrigation,
chlorination and aerated storage. Pumps and pipes should be included
for diverting flow both after screening and after irrigation to the
storage facilities. This is to permit either control of the discharge
during rainfall or of the land application during freezing weather.
ACKNOWLEDGEMENTS
This research project was a cooperative study by W. E. Reeves
Packinghouse, East Central State University, Robert S. Kerr
Environmental Research Laboratory, and the Pacific Northwest
Environmental Research Laboratory. The project was supported in part by
the US Environmental Protection Agency under Grant Number 12060 GPP and
Contract Number 68-03-0361.
Mr. W. E. Reeves, owner of the packinghouse, along with plant
maintenance and operating personnel, constructed and maintained the
treatment system. Michael Cook and Kenneth Jackson, chemistry
technicians at this Laboratory, gave outstanding performance in their
aid to packinghouse and University personnel in operating, sampling, and
278
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analytical quality control procedures. Dr. Ralph Ramsey and Mr. James
Arnold, University personnel, handled plant operation, sample collection
and weekly report preparation.
279
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REFERENCES
1. Crites, R. W., C. E. Pounds, and R. G. Smith. Experience with Land
Treatment of Food Processing Wastewater, Proceedings of the Fifth
National Symposium on Food Processing Wastes. US Governmenta
Printing Office. EPA-660/2-74-058. June 1974.
2. Witherow, J. L. Small Meat-Packers Wastes Treatment Systems.
Proceedings of the Fourth National Symposium on Food Processing
Wastes. US Government Printing Office. EPA-660/2-73-031.
December 1973.
3. Tarquin, A., H. Applegate, F. Rizzo, and L. Jones. Design
Considerations for Treatment of Meatpacking Plant Wastewater by
Land Application. Proceedings of the Fifth National Symposium on
Food Processing Wastes. US Government Printing Officer. EPA-
660/2-74-058. June 1974.
4. Law, J. R., R. E. Thomas, and L. H. Myers. Nutrient Removal from
Cannery Wastes by Spray Irrigation of Grassland. Robert S. Kerr
Water Research Center, Ada, Okalhoma. November 1969.
5. Harris, D. J. and W. J. Keffer. Performance of Automatic
Wastewater Compositors. Proceedings of the 29th Industrial Waste
Conference, Purdue University, Lafayette, Indiana. May 1974.
280
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APPENDIX
COMMON STATISTICS ON DATA BASE
Raw Wastewater - 74/01/09 to 74/06/18
Items
Temp
LWK
Flow3
DO
BOD 5
COD
PH
TS
TVS
TSS
Set. S
FOG
NH3-N
N02+N03
TKN
T-P
Fecal C
Units
°C
Ibs
gpd
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
ml /I
mg/1
mg/1
mg/1
mg/1
mg/1
/100
No.
24
24
24
24
22
24
24
24
24
24
5
5
22
22
24
24
4
Mean
22.08
32,101.66
15,710.83
2.18
634.18
1,675.29
7.53
1,970.66
1,075.79
498.62
12.50
139.40
13.42
0.39
87.88
9.77
2,387,500.00
Stan. Dev.
6.85
5,363.97
2,855.89
1.83
199.85
438.79
0.25
279.88
292.77
256.60
5.40
116.88
5.61
0.32
19.73
1.84
3,888,987.00
Maximum
32.00
41,550.00
22,180.00
7.10
1,075.00
3,120.00
8.10
2,855.00
2,138.00
1,344.00
22.00
343.80
29.30
1.00
128.40
12.65
8,200,000.00
Minimum
10.00
19,980.00
10,500.00
0.60
345.00
1,044.00
7.10
1,526.00
731.00
179.00
8.50
56.20
6.00
0.01
57.05
5.30
120,000.00
Measurable flow was within a 12-hour period.
Note: /100 = most probable number /100 ml.
281
-------
Spray Influents - 74/01/09 to 74/06/18
Items
Temp
DO
BOD5
COD
PH
TS
TVS
TSS
Set. S
FOG
Total N
NH3-N
N02+N03
TKN
T-P
Fecal C
Units
°C
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
/100
No.
24
24
21
24
24
24
24
23
5
5
21
23
22
24
24
4
Mean
20.45
0.81
374.66
960.37
7.37
1,667.62
649.75
218.82
1.70
67.46
105.50
32.20
0.43
73.97
7.23
1,487,500.00
Stan. Dev.
6.53
0.35
105.63
244.73
0.15
432.22
158.27
85.04
2.22
61.15
27.73
13.19
0.64
19.68
2.42
1,492,411.00
Maximum
30.00
1.90
530.00
1,914.00
7.75
3,504.00
1,025.00
378.00
5.00
139.90
180.30
61.67
3.20
124.70
12.40
3,700,000.00
Minimum
5.50
0.20
180.00
661.00
7.10
1,324.00
418.00
92.00
0.00
14.70
55.37
11.62
0.02
18.42
2.90
450,000.00
Note: /100 = most probable number/100 ml.
282
-------
Soil Plot No. 5 - 74/01/09 to 74/06/18
Items
Temp
Flow On
Flow Off
DO
BOD
BOD On
BOD Off
BOD Off
COD
COD On
COD Off
COD Off
PH
TS
TVS
TSS
Set. S.
TSS On
TSS Off
TSS Off
FOG
T-N
NH -N
NH -N On
NH -N
Off
NH -N
Off
NO +NO
T-N On
T-N Off
TKN
T-P
T-P On
T-P Off
Fecal C
Units,
°C
gpad
gpad
mg/1
mg/1
#ad
#ad
#/LWK
mg/1
#ad
#ad
#/LWK
mg/1
mg/1
mg/1
ml/1
#ad
#ad
#/LWK
mg/1
mg/1
mg/1
#ad
#ad
#/LWK
mg/1
#ad
lad
mg/1
mg/1
#ad
#ad
/100
No.
16
21
21
16
14
19
14
14
16
21
16
16
16
16
16
16
5
21
16
16
5
13
15
20
15
15
14
18
13
16
16
21
16
4
Mean
17.25
10,460.19
2,509.95
7.82
10.00
32.66
0.41
0.01
123.31
81.23
4.21
0.20
8.02
1,350.75
270.68
25.18
0.10
17.82
1.04
0.05
6.14
10.82
1.21
2.83
0.04
<0.01
4.04
9.42
0.35
5.58
6.75
0.59
0.17
100,300.00
Stan. Dev.
5.96
1,587.67
4,320.53
1.49
7.65
11.32
0.75
0.03
34.28
19.69
6.47
0.35
0.23
256.03
161.62
21.43
0.22
7.08
2.30
0.12
1.54
6.43
1.33
1.31
0.08
0.00
5.02
2.99
0.53
2.00
1.53
0.19
0.26
149,613.00
Maximum
28.00
13,280.00
13,800.00
11.10
26.00
51.32
2.71
0.14
194.00
128.70
20.28
1.08
8.35
2,056.00
800.00
86.00
0.50
33.75
8.99
0.48
8.60
20.74
4.50
5.53
0.28
0.01
15.00
16.19
1.71
9.80
10.80
1.04
0.86
320,000.00
Minimum
5.00
7,314.00
0.00
5.60
1.00
16.16
0.00
0.00
82.00
44.50
0.03
0.00
7.50
1,007.00
117.00
5.00
0.00
8.34
0.00
. 0.00
<5.00
3.19
0.00
1.01
0.00
0.00
0.14
3.72
0.00
2.88
4.35
0.26
0.00
1,700.00
Note: gpad = gallons/acre/day
#ad = 1 bs/acre/day
I/LWK = lbs/1,000 Ibs Live Weight Killed
/100 = most probable number/100 ml
283
-------
Soil Plot No. 6a - 74/01/23 to 74/05/08 '
Items
Temp
Flow On
Flow Off
DO
BOD 5
BOD On
BOD Off
BOD Off
COD
COD On
COD Off
COD Off
PH
TS
TVS
TSS
Set. S.
TSS On
TSS Off
TSS Off-
FOG
T-N
NH3-N
NH3-N On
NH3-N
Off
NH3-N
Off
N02+N03
T-N On
T-N Off
TKN
T-P
T-P On
T-P Off
Fecal C
Units
°C
gpad
gpad
mg/1
mg/1
#ad
fad
f/LWK
mg/1
fad
#ad
f/LWK
mg/1
mg/1
mg/1
ml/1
fad
fad
#/LWK
mg/1
mg/1
mg/1
#ad
#ad
#/LWK
mg/1
fad
fad
mg/1
mg/1
fad
fad
/100
No.
14
15
14
14
14
14
13
13
14
15
13
13
14
14
14
14
3
14
13
13
3
12
14
15
13
13
12
13
11
14
14
15
13
3
Mean
15.39
9,049.53
4,504.42
8.33
5.84
29.49
0.38
0.02
107.71
73.24
5.09
0.30
8.03
1,269.92
233.07
23.85
0.00
14.35
1.01
0.06
<5.00
13.13
0.52
2.13
0.02
0.00
8.67
8.19
0.53
4.20
5.89
0.54
0.23
16,300.00
Stan. Dev.
5.65
1,086.39
4,190.85
1.42
6.07
9.74
0.81
0.05
41.53
12.08
6.45
0.43
0.19
172.91
98.02
20.42
0.00
4.45
1.78
0.12
0.00
10.12
1.03
0.94
0.05
0.00
9.88
2.09
0.55
1.98
1.37
0.22
0.21
9,130.00
Maximum
23.00
10,720.00
14,610.00
11.30
25.00
44.06
3.04
0.19
196.00
103.90
23.87
1.52
8.40
1,512.00
426.00
65.00
0.00
20.43
5.35
0.34
<5.00
35.18
3.90
4.14
0.17
0.01
31.20
13.54
1.80
9.40
7.70
1.07
0.77
23,000.00
Minimum
5.00
7,487.00
0.00
6.50
0.80
13.52
0.00
0.00
44.00
58.87
0.52
0.03
7.60
946,00
52.00
2.00
0.00
7.26
0.07
0.00
<5.00
3.38
0.00
0.98
0.00
0.00
0.18
5.35
0.01
1.10
3.00
0.24
0.02
5,900.00
Note: gpad = gallons/acre/day
fad = 1 bs/acre/day
#/LWK = lbs/1,000 Ibs Live Weight Killed
/100 = most probable number/100 ml
284
-------
Soil Plot No. 6b - 74/05/15 to 74/06/18
Items
Temp
Flow On
Flow Off
DO
BOD 5
BOD On
BOD Off
BOD Off
COD
COD On
COD Off
COD Off
pH
TS
TVS
TSS
Set. S.
TSS On
TSS Off
TSS Off
FOG
T-N
NHj-N
NH3-N On
NH3-N
Off
NH3-N
Off
N02+N03
T-N On
T-N Off
TKN
T-P
T-P On
T-P Off
Fecal C
JJnits
°C
gpad
gpad
mg/1
mg/1
lad
lad
I/LWK
mg/1
lad
#ad
#/LWK
mg/1
mg/1
mg/1
ml/1
lad
lad
#/LWK
mg/1
mg/1
mg/1
lad
lad
#/LWK
mg/1
#ad
lad
mg/1
mg/1
lad
lad
/100
No.
5
6
6
5
5
6
5
5
5
6
5
5
5
5
5
5
1
6
5
5
1
5
5
6
5
5
5
6
5
5
5
6
5
1
Mean
27.40
16,613.33
1,119.41
6.78
5.20
47.74
0.06
0.00
103.20
110.90
1.06
0.03
8.30
1,349.00
179.40
16.80
0.00
30.50
0.21
0.00
<5.00
3.05
0.00
5.82
0.00
0.00
0.32
14.57
0.03
2.73
6.91
0.94
0.07
8,000.00
Stan. Dev.
3.13
1,208.48
1,046.51
1.07
2.48
15.49
0.07
0.00
17.93
v 25.13
0.69
0.02
0.14
197.18
33.41
7.25
0.00
13.90
0.21
0.01
0.00
0.47
0.00
1.65
0.00
0.00
0.19
5.09
0.02
0.54
0.62
0.14
0.05
0.00
Maximum
30.00
17,390.00
2,588.00
8.40
9.00
72.51
0.19
0.00
118.00
142.10
1.98
0.07
8.50
1,587.00
222.00
28.00
0.00
54.53
0.48
0.02
<5.00
3.54
0.00
8.94
0.00
0.00
0.64
22.10
0.07
3.25
7.40
1.13
0.14
8,000.00
Minimum
22.00
14,280.00
0.00
5.60
3.00
32.76
0.01
0.00
77.00
90.72
0.27
0.00
8.10
1,092.00
142.00
10.00
0.00
17.57
0.03
0.00
<5.00
2.45
0.00
4.17
0.00
0.00
0.15
7.59
0.00
2.02
5.94
0.75
0.01
8,000.00
Note: gpad = gallons/acre/day
#ad - Ibs/acre/day
I/LWK = lbs/1,000 Ibs Live Weight Killed
/100 = most probable number/100 ml
285
-------
Soil Plot No. 7a - 74/01/23 to 74/03/13
Items
Temp
Flow On
Flow Off
DO
BOD 5
BOD On
BOD Off
BOD Off
COD
COD On
COD Off
COD Off
pH
TS
TVS
TSS
Set. S.
TSS On
TSS Off
TSS Off
FOG
T-N
NH3-N
NH3-N On
NH3-N
Off
NHj-N
Off
N02+N03
T-N On
T-N Off
TKN
T-P
T-P On
T-P Off
Fecal C
Units
°C
gpad
gpad
mg/1
mg/1
fad
#ad
#/LWK
mg/1
fad
fad
#/LWK
mg/1
mg/1
mg/1
ml/1
fad
fad
f/LWK
mg/1
mg/1
mg/1
fad
fad
f/LWK
mg/1
fad
fad
mg/1
mg/1
fad
fad
/100
No.
8
8
8
8
8
7
8
8
8
8
8
8
8
8
8
8
2
7
8
8
2
7
8
8
8
8
7
7
7
8
8
8
8
1
Note: gpad = gal
Mean
13.75
6,565.37
1,154.50
8.85
6.00
21.81
0.06
<0.01
103.25
52.77
0.94
0.06
8.07
1,252.87
271.50
17.50
0.00
8.72
0.15
0.01
<5.00
15.97
0.63
1.13
<0.01
0.00
11.05
4.97
0.15
4.26
6.50
0.48
0.06
26,000.00
Stan. Dev.
6.14
951.21
826.72
1.63
2.72
6.74
0.08
0.00
36.52
11.37
0.70
0.04
0.22
171.90
182.61
9.25
0.00
2.85
0.11
0.00
0.00
7.78
0.77
0.33
0.01
0.00
7.66
0.89
0.15
1.26
1.61
0.11
0.04
0.00
Maximum
24.00
8,085.00
2,542.00
11.20
12.00
33.31
0.25
0.01
176.00
76.23
2.41
0.15
8.30
1,486.00
694.00
31.00
0.00
13.14
0.30
0.02
<5.00
25.76
2.17
1.63
0.04
0.00
22.00
6.84
0.45
7.00
8.70
0.66
0.12
26,000.00
Minimum
4.50
5,463.00
126.50
6.10
3.00
12.08
0.00
0.00
69.00
38.27
0.08
0.00
7.60
969.00
110.00
6.00
0.00
5.12
0.01
0.00
<5.00
5.15
0.00
0.64
0.00
0.00
0.65
4.13
0.01
2.70
4.13
0.31
0.00
26,000.00
ons/acre/day
fad = 1 bs/acre/day
f/LWK = lbs/1,000 Ibs Live Weight Killed
/100 = most probable number/' 100 ml
286
-------
Soil Plot No. 7b - 74/03/20 to 74/06/18
Items
Temp
Flow On
Flow Off
DO
BOD 5
BOD On
BOD Off
BOD Off
COD
COD On
COD Off
COD Off
PH
TS
TVS
TSS
Set. S.
TSS On
TSS Off
TSS Off
FOG
T-N
NH3-N
NH3-N On
NH3-N
Off
NH3-N
Off
N02+N03
T-N On
T-N Off
TKN
T-P
T-P On
T-P Off
Fecal C
Units
°C
gpad
gpad
mg/1
mg/1
lad
lad
#/LWK
mg/1
lad
lad
I/LWK
mg/1
mg/1
mg/1
ml/1
lad
lad
I/LWK
mg/1
mg/1
mg/1
lad
lad
I/LWK
mg/1
lad
lad
mg/1
mg/1
lad
lad
/100
No.
14
14
14
14
13
13
13
13
14
14
14
14
14
14
14
14
3
14
14
14
3
11
13
13
13
13
13
12
11
13
14
14
14
3
Mean
22.92
14,794.28
4,570.64
6.87
10.15
45.02
0.75
0.02
132.21
106.19
5.25
0.19
8.05
1,597.85
21S.92
26.42
0.33
27.97
1.12
0.04
<5.00
4.50
0.50
4.86
0.04
<0.01
0.78
14.25
0.14
3.91
6.47
0.71
0.21
31,133.00
Stan. Dev.
6.13
360.78
4,949.43
0.96
13.48
14.96
2.13
0.07
36.94
33.52
7.45
0.28
0.27
532.58
99.32
30.95
0.57
8.61
2.83
0.10
0.00
1.04
1.30
1.45
0.10
0.00
0.86
3.98
0.18
0.99
1.60
0.18
0.21
21,703.00
Maximum
30.00
15,460.00
17,710.00
9.00
53.00
65.88
7.82
0.29
200.00
147.90
28.65
1.06
8.60
2,700.00
490.00
116.00
1.00
46.74
10.93
0.40
<5.00
6.20
4.30
7.52
0.34
0.01
3.38
22.41
0.53
5.70
9.20
0.96
0.72
47,000.00
Minimum
9.00
14,350.00
161.00
5.00
2.00
22.37
0.01
0.00
86.00
79.12
0.26
0.00
7.60
1,014.00
122.00
4.00
0.00
15.32
0.06
0.00
<5.00
3.26
0.00
2.23
0.00
0.00
0.15
6.62
0.00
2.28
4.80
0.35
0.01
6,400.00
Note: gpad = gallons/acre/day
lad = 1 bs/acre/day
I/LWK = lbs/1,000 Ibs Live Weight Killed
/100 = most probable number/100 ml
287
-------
WASTEWATER MANAGEMENT AT HICKMOTT FOODS, INC.
George Tchobanoglous*
Bill Ostertag**
Ed Fernbach***
INTRODUCTION
Hickmott Foods, Inc., is a small independent cannery located in
Antioch, California. In the past, the principal items processed were
tomatoes, asparagus, and sweet potatoes. The sweet potato and asparagus
operations were abandoned after the 1973 and 1974 seasons, respectively,
leaving tomatoes as the only commodity to be canned in 1975. Tomatoes
are canned in an 80-day operating season during the months of July
through October. With the exception of a week or two at the beginning
and end of the season, the canning operation is continuous around the
clock. In 1971, to meet waste discharge requirements established by the
Central Valley Water Quality Control Board, Hickmott Foods undertook a
program of wastewater management to clean up its wastewater discharge to
the Sari Joaquin River. Because no municipal system was available to
handle the cannery wastes, Hickmott Foods was forced to develop its own
waste treatment system or cease to operate.
The purpose of this paper is to summarize the nature and results of
water pollution control efforts at Hickmott Foods. Both the in-cannery
modifications and the operation of the newly constructed wastewater
treatment facility are discussed. Topics to be considered include: (1)
waste quantities and water quality objectives; (2) in-plant facilities
for waste flow and strength reductions; (3) wastewater treatment
facilities including waste characteristics, treatment process operations
and costs; and (4) future developments with respect to wastewater
management.
*Associate Professor, University of California at Davis, Davis,
California.
**Food Industry Consultant, Pittsburg, California.
***Project Engineer, Trotter-Yoder and Associates, Walnut Creek,
California.
288
-------
WASTE QUANTITIES AND WATER QUALITY OBJECTIVES
The amounts of waste produced during the 1974 tomato canning season
and the discharge requirements imposed by the US Environmental
Protection Agency and the Central Valley Regional Water Quality Control
Board are considered in this section. To allow valid comparisons to be
made with other similar operations, waste production and discharge
quantities are also presented on a unit production basis (e.g., pounds
per ton of raw material processed).
Waste Quantities
Approximately 1,050 tons of raw mechanically and hand harvested
tomatoes are processed daily at Hickmott Foods. Production data for the
1974 season are summarized in Table 1. The 1974 production figures
given in Table 1 represent a 21 percent increase in tonnage over the
1973 canning season. Of the daily total, 880 tons of finished product
and 170 tons of waste are produced per day.
Wastes from the totamo canning operation at Hickmott Foods are in
three forms: (1) solid wastes such as whole tomatoes and tomato skins,
seeds, and stems, (2) sludge from the caustic peeling of raw tomatoes,
and (3) wastewaters which contain suspended and soluble tomato
components, sand, and silt. The quantities and characteristics of these
wastes are shown in Tables 2 and 3.
Of the 170 tons of tomato components that go to waste each day (see
Table 2), 39 tons are hauled away as solids for cattle feed, 120 tons of
caustic tomato sludge are generated per day from the dry peeling
operation, and approximately 11 tons per day of raw product is lost in
the wastewater flow stream.
The characteristics of the wastewater that would have to be treated
if the peeling sludge were to be dumped into the plant sewer, as was the
practice before the 1974 canning season, is also shown in Table 3.
Presently, the peeling sludge is isolated and trucked away for land
disposal. Studies are underway to determine the feasibility of
recycling this sludge to recover much of this lost food value (see
section Dealing with Future Developments).
Discharge Requirements
Hickmott Foods was given its first set of discharge requirements in
1971 and was issued an NPDES permit on January 1, 1975. These
requirements are shown in Table 4. Based on the requirements set forth
289
-------
Table 1. PRODUCTION DATA FOR 1974 TOMATO CANNING SEASON*
Value
Item
Raw product delivered
Daily average, tons/day
Season total, tons
Finished products
Peeled tomatoes, tons/day.
Tomato products, tons/day
Total, tons/dayc
Raw product loss in processing
Quantity, tons/day
Percentage, percent
1,050
59,000
500
380
880
170
16
Averages for full 24-hour operating day.
Calculated from pack reports.
r*
"Caluclated from pack reports, standard case per ton
conversion factors and estimated loss in evaporation and
waste.
290
-------
Table 2. WASTE GENERATION DURING 1974 TOMATO CANNING SEASON
to
CD
Item
Solid wastes, tons/day
Peeling sludge at 7% solids, tons/day
Loss of tomato in wastewater,
tons/day6 >f
Total loss of raw product as waste,
tons/day
Value
With
peel ,
recovery
39
120
11
170
Without
peel
recovery
37
0
133
170
Unit value9
With
peel .
recovery
74
228
21
323
Without
peel
recovery
70
0
253
323
aUnit production values are on a gal./ton or Ib/ton of raw tomato basis (whichever is
applicable).
Current method of operation.
cPredicted quantities based on measured values for peeling sludge COD, suspended solids,
and flowrate.
d32,400 gal./day
eBased on waste characteristics given in Table 3.
f1.0 pound of whole tomato yields 1.3 pounds of COD (COD of whole tomato = 73,000 mg/1, TSS
of whole tomato = 55,000 mg/1).
-------
Table 3. WASTEWATER CHARACTERISTICS DURING 1974 TOMATO CANNING SEASON
IS3
-------
Table 4. WASTE DISCHARGE REQUIREMENTS*
Constituent
Process wastewater
Daily flow, mgd
BOD 5, Ibs/day
Total suspended solids, mg/1
Total suspended solids, Ibs/day
Settleable matter, ml /I
Oil and grease, mg/1
pH
96-hour bioassay, % survival
Minimum, any one bioassay
Median, three or more
consecutive
Cooling water
COD, mg/1
Temperature, F
Value
30-day
average
800
75 (50)
820
0.2 (0.5)
10
70 (100)
90
Daily
maximum
1.3
1,890
125 (75)
1,360
0.5 (1.0)
15 (10)b
6.5-8.5°
50C
20° above.
background
Effective January 1, 1975, previous requirements shown in parenthesis.
Range.
cAverage value above background.
Combined process and cooling water discharge shall not exceed 20°F
above the temperature of the San Joaquin River or 80 to 90°F.
293
-------
in Table 4, Hickmott Foods must remove 94 percent of the BOD5 and 91
percent of the total suspended solids from its wastewaters before
discharge.
WASTE MANAGEMENT IN CANNERY
Significant reductions in the wastewater flowrate and strength have
been accomplished by modifying various operations within the cannery
production area. These changes and their impact are discussed in this
section.
Wastewater Flow Reduction
The two principal components of the wastewater produced during the
1973 and 1974 tomato canning seasons are the process water and the water
from the evaporators and retorts (see Table 5). Water used in the
production process is derived primarily from the domestic water supply
of the City of Antioch; whereas, the water used to cool the evaporators
and retorts is filtered San Joaquin River water.
Several steps were taken between 1973 and 1974 to reduce the
quantity of water used by the cannery and to reduce the wastewater
flowrates. The cooling water was analyzed and found to be suitable for
direct discharge to the river (COD less than 50 milligrams per liter)
after cooling. Eliminating the cooling water from the waste stream
reduced the flow requiring treatment from 3.1 million gallons per day to
1.14 million gallons per day, while cannery production increased 20
percent.
The installation of four dry peel removal machines reduced the
total water needed for peeling from 306 to 124 gallons per minute. The
quantity of peel sludge produced dropped from 150 to 25 gallons per
minute while cannery production increased 20 percent. This reduced
amount of peeling sludge now made it possible to isolate this material
and process it separately.
All low pressure-high volume washdown hoses were removed and a high
pressure hose system with nozzles that shut off upon release was
installed. This change resulted in a washdown flow reduction of at
least 80 gallons per minute (see Table 5). As low pressure hoses are
usually left to run on the floor, the reduction was probably somewhat
larger. Some employees objected to the use of the high pressure spray,
as it is harder to control, but eventually became accustomed to using
294
-------
Table 5. DAILY WATER USAGE DURING 1974 CANNING SEASON AND PERCENT
REDUCTION DATA OVER 1973 CANNING SEASON9
Tfpm
Jl LCI II
No
llv-l •
Description of Source
1974
Flowrate,
gpm
Percent
Reduction
over 1973
Process Wastewaterb
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Seals on sump pump (1/2" line, 2 @ 8.8 gpm)
Bin washing system (2 @ 17.5 gpm)
Incoming product sprays 2 @ 10 gpm)
Small tomato dropout fluming to product tables
Make-up water to lye peelers (2 @ 10 gpm)
Rinse tanks after peeling (2 @ 50 gpm in 1973)
Dry scrubbers (4 @ 6 gpm) (1 @ 50 gpm in 1973)
Rinse water on roller washers (4 @ 20 gpm) (4 @ 35 gpm in 1973)
Belt lubrication and cleaning
Can washers, 7 peel i no, 3 product (10 @ 18 gpm)
Kettles (1" line, 1 @ 30 gpm)
Washdown lines, low pressure (4 @ 35 gpm in 1973)
Washdown lines, high pressure (6 @ 10 gpm)
Can cooling, outside coolers (7 @ 35 gpm)
Cooling water, vacuum pumps (3 @ 8.8gpm)
TOTAL WASTEWATER GENERATED, gpm (1126 gpm in 1973)
18
35
20
35
20
°u
24t>
80d
506
180"
30
°f
60f
245
27
800
_
.
.
-
.
100
52
43
-
-
.
100
-
-
-
~Z9~
Evaporators & Retorts9
16
17
18
Evaporator No.
Evaporator No.
Retorts
1
2
550
350
100"
1,000
_
-
69
17
Fluming Water1'
19 Tomato fluming
600
aBas"ed on individual flowrate measurements during 1973 and 1974 peak production periods.
''All process wastewater must be treated by the wastewater treatment facilities except Item 7.
See section on Dry Peeling.
cEliminated from 1973 operation.
''Reduced by lowering spray pressure.
eTo be reduced in 1975 by shortening belt runs.
^Nozzles shut off when not in hand of operator.
9Water from evaporators and retorts is discharged directly to river after passing through
cooling tower.
hRetort water is recovered and used for can washing.
^Fluming water is recycled internally. Make-up water is obtained from Items 3 & 4.
295
-------
these nozzles. No degradation in the quality of the product or plant
sanitation was observed.
Cooling water discharge was reduced by 200 gallons per minute by
reusing the retort cooling water for can washing. Besides reducing the
amount of water to be cooled before discharge to the river, the amount
of river water that must be filtered and chlorinated for use in the can
washing system was also reduced.
Organic Waste Reduction
The quantity of raw tomato constituents present in the process
wastewater was reduced from the 1973 to 1974 season by modifications in
the peeling operation and floor waste management.
Dry Peeling—The installation of four dry peel removal machines and
modifications in the operation of the caustic peelers has resulted in a
reduction in chemical usage and the quantity of waste generated that
must be treated. This has been accomplished with no deterioration in
product quality. Dry caustic peeling, using rotating rubber discs to
mechanically rub peel from tomatoes dipped in sodium hydroxide, replaced
the conventional water rinse peeling operation. Effective peeling was
obtained with this method while reducing the concentration of caustic in
the peelers. Operational data for the peelers are summarized in Table 6
for the 1973 and 1974 seasons. Through a combination of reducing the
peeler speed (resulting in more tomatoes per bucket but a longer contact
time with the caustic per tomato) and using mechanical peeling, it was
possible to use a caustic solution of 7 to 10 percent in 1974 as opposed
to an 18 to 20 percent solution in 1973. This mode of operation
resulted in a reduction in caustic usage (6.9 pounds per ton in 1974 as
opposed to 11.7 pounds per ton previously) and reduced chemical
requirements for neutralization of the resulting wastewater. As
discussed in a later section reducing the pH value of the caustic sludge
can also make the possibility of product recovery more practicable.
Dry caustic mechanical peeling requires about 80 gallons of potable
water per ton of tomatoes as opposed to 720 gallons per ton using
conventional methods. The 80 gallons per ton which amounted to 24
gallons per minute of caustic sludge in the Hickmott Foods operation is
a small enough volume that it can be disposed of in a land spreading
operation. The characteristics of the caustic sludge generated during
1974 are summarized in Table 7 in the following section. The exclusion
of this sludge from the waste stream to the water pollution control
plant reduced the BOD5 load on the facility by 46 percent.
296
-------
Table 6. SUMMARY DATA ON CAUSTIC TOMATO PEELING OPERATION
AND ACID USAGE AT HICKMOTT FOODS, INC.
Parameter
Number of caustic peelers
Peeler spped, buckets/mi n,
each
Loading rate, tons/mi n, each
Caustic solution in peeler, %
Total season throughput, tons
Caustic usage, tons
Unit caustic usage, Ibs/ton
Acid usage, tons
Unit acid usage, Ibs/ton
Season
1973
4
40-44
0.33
18-20a
29,000
198b
11.7
71c,d
4.9
1974
4
24-28
0.33
7-10a
35,000
121b
6.9
53C'e
3.0
Reduction
1974 over 1973,
%
41
39e
Estimated average from operator titrations.
50% sodium hydroxide used.
C93% sulfuric acid used for neutralization of wastewater at treatment
facilities.
All caustic peeling sludge entered treatment system.
eOnly a small portion of the caustic sludge entered the waste treatment
system. Tighter restraints imposed on neutralization system offset
expected acid usage reduction.
297
-------
Table 7. INFLUENT AND EFFLUENT WASTEWATER CHARACTERISTICS
DURING THE 1974 TOMATO CANNING SEASON
tSS
(D
00
Constituent
Total flow, gpm
Total flow, mgd
Suspended solids, total, mg/1
Volatile, mg/1
Fixed, mg/1
BODS, total, mg/1
Soluble, mg/1
TOC, total, mg/1
Soluble, mg/1
COD, total, mg/1
Soluble, mg/1
Normal operation
without peeling sludge
Influentb
1,000
400
600
1,300
1,100
1,100
900
3,200
2,700
Effluent0
800
1.14
60
20
40
30
20
50
30
120
90
With peeling sludge
in waste stream
Influentb
1,200
—
1,800
1,200
1,600
-
5,500
5,000
Effluent0
825
1.18
60
20
40
30
20
60
-
200
150
aValues based on limited operational data obtained during periods when peeling sludge was
discharged to waste stream.
bAfter screening with a 20-mesh vibrating screen.
cAfter biological treatment.
-------
As shown on Table 3, if the peeling sludge had not been handled
separately the BOD5 of the wastewater in 1974 would have been 2,400
milligrams per liter as opposed to the 1,300 milligrams per liter
actually measured.
Floor Waste Management—Because tomatoes are, for the most part, a
water soluble fruit, the longer they remain on the cannery floor or in a
wastewater conveyance facility, the more the tomato solids and juices
contribute to the soluble COD and BOD5 of the wastewater. If processing
wastes are picked up in solid form they can be fed to livestock or at
least trucked to disposal as solid wastes. Manual collection of large
solid tomato parts was stressed during the 1974 season. Gratings on all
floor drains were also bolted down. Reliable solid waste per ton data
were not available for the 1973 season but it is estimated that
considerably more solid waste was trucked to cattle feed during the 1974
season. This is waste that does not reach the treatment facility as
fine suspended matter or soluble organics.
WASTEWATER TREATMENT FACILITIES
Construction of wastewater treatment facilities began in 1973 and
after modification of the original design, the current plant was
operational for the 1974 canning season. The purpose of this section
is, therefore, to present and discuss the wastewater treatment system
used at Hickmott Foods. Topics to be considered include: (1) the
characteristics of the wastewater to be processed, (2) the treatment
process flowsheet, (3) the individual unit operations and process
comprising the treatment system, and (4) the associated treatment costs.
Wastewater Characteristics
Eight-hour composite samples of the wastewater were taken weekly
during the 1974 operating season. Constituent concentrations determined
for both the raw wastewater and treatment process effluent are reported
in Table 7. As shown, the COD of the raw wastewater is about 2.3 times
the BOD5 as compared to 2.5 for most domestic wastes. The BOD5 values
shown in Table 7 are those obtained from the BOD5 test as delineated in
Standard Methods.1 The BOD5 values were found to increase by about 20
to 25 percent when the bacterial seed for the test was acclimated to
tomato peeling sludge. It was also found that the BOD5 value was
approximately 55 to 65 percent of the ultimate BOD value when using
acclimated seed. If it is assumed that the reported BOD>5 value (1,300
milligrams per liter) is about 80 percent of the acclimated value and
that the acclimated value is 60 percent of the ultimate BOD value, the
299
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ultimate value would be computed to be 2,710 milligrams per liter. This
compares reasonably well with the COD value (3,000 milligrams per
liter). The total organic carbon values are slightly less than the
conventionally determined BODS values. For this particular tomato
waste, the TOC can be used as a quick indication of the BODs.
Over 50 percent of the influent suspended solids are fixed solids
such as clay, silt and sand. Because separate dirt removal facilities
are not used, all of the dirt, save what is settled out in the dump tank
or can be shoveled into a dump truck, is pumped to the treatment
process. The impact of this inert material is discussed in the sections
dealing with nutrient requirements and sedimentation basin performance.
Treatment Process Flowsheet
Hickmott initiated the design and construction of wastewater
treatment facilities in 1972. In the original design, large solids were
removed with vibrating screens before the wastewater was sent through a
series of centrifugal screen separators. From there, the waste was
neutralized and discharged into a two-stage aerated lagoon system which
was mixed and aerated by circulating the lagoon contents through
pressurized tanks. Sedimentation facilities were not included in the
original design. It was soon realized by Hickmott Foods and their first
consultant that this system could not meet discharge requirements.
Unfortunately the wastewater had not been characterized adequately
before the plant was constructed. Because the centrifugal screens were
overloaded hydraulically, it was not possible to produce a tomato sludge
thick enough to make hauling feasible. Although the treatment process
did reduce the soluble organic content of the waste, because liquid-
solids separation facilities were not provided, the suspended solids
concentration in the effluent was as high or higher than the original
waste stream. In addition, the cooling water discharge was part of the
waste flow. This put an additional hydraulic loading on the treatment
plant and reduced the detention time in the treatment system.
A new consultant was retained by Hickmott Foods, the treatment
flowsheet was modified, and the necessary construction was completed in
time for the 1974 operating season.2 The modified process flowsheet
currently in use in shown in Figure 1. The vibrating screens,
neutralization facilities and the effluent disposal portion from the
original flowsheet were retained. The two lagoons have been converted
to aeration and sedimentation basins. Sludge is recycled from the
sedimentation basins back to the aeration basin. Cooling water is
treated separately but is discharged through a common outfall. A plan
view of these facilities is shown in Figure 2 and pictorial views are
300
-------
CO
o
I
1
1
PEELING SLUDGE )
V ""^^""
1
1
1
COARSE
TOMATO SOLIDS
1
1
\
1
i
WASTE SOLIDS oh
*,,ue SEPARATION ph
SUMP FACILITIES
SLUDGE
STORAGE
TANK
WASTE ACTIVATi
SLUDGE
STORAGE TANK
OVERFLOW
' ADJUSTMENT
TANK
SLUDGE
THICKENERS
TO
1
i i
\
COOLING WATER
1
COOLING
TOWER
\ '
TREATED
ff-f/ IICMT
SUMP
AERATION SEDIMENTATION
BASIN BASINS
Figure 1. Flowsheet for wastewater treatment process.
(Put into operation in 1974.)
-------
FLOATING AERATORS
GO
o
to
WATER SURFACE
WASTEWATEa
INLET MANIFOLD
SLUDGE OVERFLOW TANK
SLUDGE PUMPS TO THICKENERS
VIBRATING SCREENS
STORAGE HOPPERS UNDERNEATH
PEELING SLUDGE TO
SLUDGE STORAGE HOPPER
WASTEWATER INFUOHf
TREATED EFFLUENT,
TO RIVER
COOLING WATER
FROM CANNERY
SLUDGE THICKENERS
EFFLUENT SUMP
AND PUMPS
CABLE TIES
FLOATING OVERFLOW WEIR
pH ADJUSTMENT
TANK
-SCVM rtETURN
SLUDGE RETURN PUMPS
SCUM TROUGH
SCUM SUMP AND PUMPS
SLUDGE INLET MANIFOLD
-TRAVELING BR/OGf SLUDGE
REMOVAL MECHANISMS
ELECTRICAL CABLE TROLLEY
FOR TRAVELING BRIDGE -
Figure 2. Plan view of wastewater treatment facilities.
-------
presented in Figure 3. The performance of each of the unit operations
and processes is discussed below.
Unit Operations and Processes
The individual unit operations and processes that comprise the
treatment system of Hickmott foods are considered in this section. They
include: (1) raw solids separation, (2) neutralization and nutrient
addition, (3) activated sludge process, (4) sedimentation, (5) activated
sludge waste solids thickening, (6) sludge disposal, and (7) cooling
water treatment.
Raw Solids Separation—The raw solids separation facilities consist of
two 60-inch diametertwo-stage vibrating screens. The screens are
cleaned by the vibratory motion of the screens and the rotating spray
headers. Approximately five tons per day of raw tomato solids, twigs
and cans are removed from the waste stream using 20-mesh stainless steel
screens. About 50 percent of the total suspended matter that reaches
the treatment facility is removed with the screens. This material is
discharged directly into a storage hopper. Screened solids are trucked
to nearby ranches for cattle feed.
Neutralization and Nutrient Addition—Before further treatment, the
wastewaterpHTsadjustedto between 6.5 and 8.5. Neutralization is
accomplished in a two compartment tank. The detention time in each
compartment at average flow is about 20 minutes. Sulfuric acid addition
to each compartment is controlled with a pH probe and individual
controllers are used for rough and fine pH adjustment. Sulfuric acid
usage during the 1973 and 1974 canning seasons is shown in Table 6. The
acid dosage ranged from 20 to 60 milligrams per liter of H2SO.».
Nitrogen and phosphorus as well as many trace elements are
essential to the growth of microorganisms in the aeration basin.3 The
estimated nitrogen and phosphorus requirements as well as the range in
concentrations of these nutrients measured in the tomato wastewater are
reported in Table 8. During most of the canning season, the nitrogen
and phosphorus levels in the wastewater are near the upper end of the
ranges shown in Table 8. However, during the early part of the canning
season when tomatoes are harvested from the southern portion of
California's Central Valley, nutrients must be added because the sandy
soils in this area contain few, if any, adsorbed nutrients. As Hickmott
Foods has no prior removal of sand, silt and clay, the NHj and PO^3
associated with the inorganic solids serve a major nutrient source. As
the clay and silt content of the soil increases as harvesting moves up
the Central Valley, nutrient addition is not required. The reduced
nitrogen and phosphorus levels also occur at the time of process start-
303
-------
AERATION BASIN WITH SURFACE AERATORS IN OPERATION
LINED EARTHEN SEDIMENTATION BASIN
Figure 3. Photographs of wastewater treatment facilities,
(Continued on next page.)
304
-------
:
•
I
o
IQ
-.
PI
:--
,.--
O
,
•
•
i
•
CENTRAL SLUDGE TROUGH AND
TRAVELING BRIDGE SLUDGE REMOVAL MECHANISMS
SLUDGE PUMPS ON TRAVELING BRIDGE
•i
I/I
TRAVELING BRIDGE, SLUDGE PICKUP ASSEMBLY,
AND EFFLUENT TROUGH
DETAIL OF SLUDGE PICKUP ASSEMBLY
-------
Table 8. NUTRIENT REQUIREMENTS ACTIVATED SLUDGE PROCESS AND QUANTITIES
AVAILABLE IN WASTEWATER FROM TOMATO CANNING OPERATIONS
Constituent
Total Kjeldahl nitrogen as N
Total phosphorus as P
Amount
required,
Ib/day
417b
85C
Amount available
in wastewater
Cone.,
mg/1
20-90
4-12
Total ,a
1 b/day
190-856
38-114
Average dialy flor of 1.14 mgd.
12.4% of the total daily volatile solids production in activated
sludge process during normal operation.
C2.5% of the total daily volatile solids production by activated sludge
process during normal operation.
306
-------
up. The presence of filament!ous organisms (sludge bulking) and the
absence of the protein foam usually present on top of the aeration basin
were observed until supplemental nutrients were added. When nitrogen
and phosphorus are added in the form of aqueous ammonia and phosphate
fertilizer until traces of ammonia, nitrate or phosphate are observed in
the effluent bulking is eliminated and the surface foam reappears.
Activated Sludge Process—After neutralization, the wastewater flows
into the aeration basin where waste tomato organics are converted to
bacterial cell material. The physical configuration of the aeration
basin is shown in Figure 2. Six 60-horsepower floating high-speed
aerators are used to provide oxygen to the process and to mix completely
the contents of the basin. Normally all six aerators are operated
continuously. However, to save power costs the units could be turned
off and on as the demand warranted. A Hypalon liner is used to prevent
erosion by the aerator turbulence. Biological solids are separated from
the flow stream in sedimentation basins and are returned to the aeration
basin. The net biological solids produced each day are removed daily
from the treatment system.
The physical characteristics of the aeration basin and the
activated sludge process operational parameters are reported in Table 9.
As shown, the process can be classified as extended aeration activated
sludge (mean cell residence time typically greater than 12 days). With
the existing aeration and mixing capacity, it was possible to maintain
mixed liquor suspended solids concentrations ranging from 9,000 to
15,000 milligrams per liter while holding a dissolved oxygen
concentration of 4 to 5 milligrams per liter. High solids
concentrations, however, may result in problems in the design and
operation of sedimentation facilities. This subject is discussed
further in the following section.
The observed advantages of this process in terms of process
performance and reliability are as follows.
1. Because of the low food-microorganism ratio, the process is
less susceptible to upsets caused by high organic shock
loadings.
2. Becuase high levels of dissolved oxygen can be maintained,
higher forms of microorganisms are present and a very clear
effluent is produced (4 feet on a standard secchi disc).
3. Because the process can be operated in the extended aeration
mode, a sludge is produced that settles well and carries down
colloidal silt and clay particles.
307
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Table 9. PHYSICAL CHARACTERISTICS AND OPERATIONAL PARAMETERS FOR THE
ACTIVATED SLUDGE PROCESS MEASURED DURING 1974 TOMATO CANNING SEASON
Item
Aeration basin characteristics
Volume, mg
Aeration time, hrs.
Aerators, number
Aerators, horsepower
(6 @ 60 hp/aerator
Oxygen transfer rate,a Ib 02/hp-hr
Mixing, hp/1,000 gals.
Dissolved oxygen concentration, mg/1
Process operational parameters
MLSS under aeration, mg/1
Percent volatile
F:M (food to microorganism ratio),
Ib BOD 5/1 b MLVSSC
Ib COD/1 b MLVSSC .
Mean cell residence time, days
Yield coefficient,
Ib cells/lb BOD5
. Ib cells/lb COD
Sludge production,6 Ib VSS/day
Range
2.0-4.5
2.0-6.0
8,000-15,000
40-75
8-20
0.30-0.60
0.13-0.26
3,700-7,400
Average
1.10
24
6
360
3.0
0.33
4.5
10,000
55
0.28
0.49
12
0.58
0.24
Calculated on the basis of COD satisfied (see Table 7).
Mixed liquor suspended solids.
cMixed liquor volatile suspended solids.
Calculated on basis on cells in aeration basin only.
eSludge production varies with mean cell residence time.
308
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4. Because the process can be operated in the
mode, nutrient requirements are reduced.
extended aeration
The process was monitored with daily observations of the bacterial
population because it was found that process changes and stress
conditions could be observed before they would effect overall treatment
efficiency. When the process is operating normally, the bacterial
population is composed primarily of small bacteria with large numbers of
stalked ciliates (Vorticella) and many free swimming ciliztes and
rotifers (PhilondinaTThe presence of these higher forms was used as
an indicationthat the process was operating properly. The following
conditions would cause the disappearance of the higher forms.
1.
2.
3.
4.
Dissolved oxygen levels below 3.0 to 4.0 milligrams per liter--
It is possible that with high mixed liquor solids the dissolved
oxygen transfer efficiency is impaired at lower concentrations.
High organic loadings—When the process was in the dispersed
growth phase, it was observed that the higher forms did not
compete as well as the simpler bacterial forms.
Toxic substances or nutrient deficiencies—These problems
also found to effect the higher forms.
were
pH control--If the pH control system was turned off, it was
observed that the ciliates and rotifers could not adapt to pH
fluctuations and would soon disappear.
Filamentious bacteria were not present under
unless the following conditions prevailed.
normal operation
1. Nutrient deficiencies—When the supply of nitrogen and
phosphorus was below that required by the process for extended
periods of time, filaments would begin to predominate and cause
sludge bulking.
2. Low dissolved oxygen levels—When dissolved oxygen concen-
trations remained below 2.0 milligrams per liter for extended
periods, the population of filamentious organisms would rise.
Sedimentation Facilities—The sedimentation facility was constructed in
anexisting pond which was once used as an aerated lagoon.
Modifications to the old lagoon included the addition of concrete and
walls, the fabrication of an inlet manifold, center rail support
structure and effluent weir troughs, and the installation of two
electric motor-driven traveling sludge removal mechanisms. The dirt
309
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basin is lined with Hypalon. Neoprene rubber skirts are used to push
sludge to the pick-up points on each bridge (see Figure 3).
Sedimentation basin loadings and performance characteristics are
summarized in Table 10. The high mixed liquor suspended solids levels
and the settling characteristics of this sludge result in a solid-liquid
separation process that is solids limited. The activated sludge process
could not be operated in the extended aeration mode or with the high
mixed liquor suspended solids levels with a smaller sedimentation basin.
The traveling bridge sludge return mechanism allows for the
flexible operation of the sedimentation facility. The sludge return
rate can be varied by adjusting the self-priming sludge pumps on each
bridge. Under normal operation, the bridge travel rate is 5 feet per
minute. Return sludge is discharged into an overhead trough and flows
by gravity back to the aeration basin or is pumped to the sludge
wasting facilities. Two profiles of the return sludge concentration as
a function of distance along the basin are shown in Figure 4. Because
each profile is for a different sludge return rate, the degree of
thickening obtained is also illustrated. As shown in Figure 4, the
return sludge concentration remains constant until the pick-up
mechanisms reaches the effluent end of the basin and then rises sharply.
In this case, the bridge is moving through the sludge blanket faster
than the sludge is being pumped. Some of the sludge passes over the
pick-up head and upon approaching the effluent end, the thickened sludge
is squeezed against the end wall. In such a situation, the return rate
should be increased or the bridge travel speed reduced to obtain a more
uniform return sludge profile.
Because the sedimentation facility was solids limited hydraulic
surges caused the transfer of solids from the aeration basin into the
sedimentation basin at a rate much faster than they could be settled and
pumped back to the aeration basin. If the surges were of short
duration, the sludge return facilities would catch up with the rising
sludge blanket. However, if the duration of the flow surge was too
large, a deterioration in effluent quality would ultimately result.
As noted previously, Hickmott Foods has no sand, silt, and clay
separation from its wastewaters. During periods of stable process
operation, it was observed that the small colloidal clay particles
present in the wastewater are carried down with the bacterial flow. But
during periods when the sludge is not settling well when the bacterial
process is in the log growth phase (such as when the cannery is starting
up after being down) some of the clay particles escape into the
effluent. When this occurred, the ratio of volatile to total suspended
solids in the final effluent would decrease. This ratio was as low as
0.25 when the corresponding total effluent suspended solids was 75
310
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Table 10. SEDIMENTATION BASIN CHARACTERISTICS, LOADINGS, AND
PERFORMANCE DATA
Item
Value
Basin characteristics
Number
Average surface area, sq ft, each
Liquid depth, ft
Volume, mg, each
Detention time at 2.28 mgd, hr, total
Design loadings
Hydraulic loading rate including 100% recycle flow,
gal./sq ft/day
Solids loading rate including 100% recycle flow
Ib/sq ft/day
Weir loading, gal./day/linear ft
Return sludge,
Flowrate, gpm
Percent of average flow
Effluent quality
Suspended solids,
Range, mg/1
Average, mg/1
Volatile fraction
Secchi disc readings, ft
2
4,080
6.5
0.20
4.2
280
23
11,400
800
100
9-75
60
33
1-4
311
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-I ' I
2min. PAUSE AT
EFFLUENT WEIRS
INLET END
I I • I L
EFFLUENT WEIRS
MLSS - 9,2OO mg/l
RETURN FLOWRATE
BRIDGE TRAVEL SPEED
Sfpm
INLET END
I . I
I i I
I i I » _ I _ 1_L
_L
SO 4O 6O SO IOO 120 120 IOO 8O
BRIDGE POSITION, ft.
60 40
1
2 -
MLSS - 9,20O mg/l
RETURN FLOWRATE * I.OOO gpm
BRIDGE TRAVEL SPEED - Sfpm
2mia. PAUSE AT
6aiin. PAUSE AT
EFFLUENT WEIRS
INLET END
'.III.
EFFLUENT WEIRS
^^^^^^^M^^^^^^^^^^
I . I I I . I
INLET END
-i_J — . — I
I
I
X
2O 4O SO 8O IOO I2O 120 IOO SO
BRIDGE POSITION, ft.
go 40 2O
Figure 4. Return sludge concentration profiles.
312
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rnilligrams per liter (normal value of volatile to total suspended solids
ratio in mixed liquor was approximately 0.55).
Activated Sludge Waste Solids Thickening—For process control the
bacteria1! cells grown each day must be wasted. Wasting is accomplished
by pumping returned sludge through a three-stage centrifugal screen
thickenng operation. In the centrifugal screen, the sludge is pumped
through a distributor against a rotating polyester screen with 43 micron
openings. Water and some solids pass out through the rotating screen
cage (200 to 400 revolutions per minute) and the thickened sludge is
discharged out the bottom. The capture efficiency of each of these
units is approximately 50 percent and after a single pass through the
sludge is thickened by approximately 25 percent. A schematic with the
various flow rates, sludge concentrations and total pounds wasted daily
is shown in Figure 5. Because the clay silt particles in the waste
sludge blind the screens, a thicker final sludge could be obtained if
this material were eliminated.
Sludge Disposal---Raw tomato solids are trucked away to nearby ranches
for cattle feed. Sludge from the peeling operation is combined with the
waste activated sludge and approximately 20 loads per day (3,000 gallons
per load) are hauled away by tanker for land spreading at the disposal
site. After spreading, the sludge is allowed to dewater for 24 hours
before being disced into the soil.
Cooling Water Treatment—Cannery cooling water is treated in a single
cooling tower and discharged along with the wastewater treatment process
effluent to the San Joaquin River through a common outfall. The Central
Valley Regional Water Quality Control Board has tentatively set 50
milligrams per liter as the maximum COD increment concentration over
background to be allowed in cooling water discharge. This value is
subject to change after more data are gathered during the 1975 operating
season.
Treatment Costs
The purpose of this section is to (1) briefly summarize the capital
expenditures involved in the construction of the Hickmott waste
treatment facility, (2) identify the daily operation costs, and (3) put
these costs into perspective with respect to production costs.
Capital Costs—Capital expenditures for the Hickmott Foods wastewater
treatment facility are reported in Table 11. As shown, the total cost
of the plant at $885,000 (ENRCC Index = 2,240) is about one-half that of
a comparable conventional secondary treatment plant design. The use of
earthen basins, for both aeration and sedimentation are most significant
313
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CENTRIFUGAL
SCREEN
CONCENTRATOR
PUMPS
TO AERATION BASIN -«
77gal/aiin
U> percent solids
I29gal/atin
2.1 percent solids
RETURN
SLUDGE
\52gal/min
CENTRIFUGAL ] 2.6 percent solids
SCREEN
THICKENER
TO AERATION BASIN
31 gal_/min_ ]_
2.2 percent solids
r^i
v_^r
BYPASS
TO AE*AT,ON BASiN
2.7 percent solids
2/ gal/min
3.2 percent solids
BYPASS
8.5 gal/min
4.0 percent solids
PUMPS
TO AERATION BASIN —-
12,000 gal/day
4,OOO Ibs. solids/day
CENTRIFUGAL
SCREEN
THICKENER
\
SLUDGE
STORAGE
HOPPER
Figure 5. Flowsheet for waste sludge thickening facilities.
314
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Table 11. SUMMARY OF CAPITAL COSTS OF WASTEWATER TREATMENT FACILITIES4
Item
Cost, dollars
Major equipment
Aerators
Clarifier mechanisms
Sludge thickeners
Other equipment
Soil excavation, filling, grading, paving, etc.
Concrete work
Structural steel and supports
Pond liners
Piping, fittings and installation
Crane and rigging
Fencing and landscaping
Electrical sub-station, hook-ups, equipment and
installation
Permits, impact report and other governmental fees
SUBTOTAL
Plant labor
Design, civil, soil, marine engineering and general
contracting expenses, etc.
TOTAL
$ 36,000
76,000
45,000
101,000
70,000
200,000
47,000
21,000
95,000
5,000
7,000
74,000
1,500
$778,500
58,500
49,000
$885,500
Engineering News Record Construction Cost Index for San Francisco Bay
Region = 2,240 (January 1974).
315
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in terms of cost savings. Use of traveling bridge sludge pick-up
mechanisms in a lined earthen basin makes possible an efficient and
flexible sedimentation operation at a considerable cost savings over
conventional designs employing concrete or steel tanks. Hickmott Foods
was also able to reduce construction costs by doing the majority of the
general contracting and labor with cannery personnel.
Operational Costs—Operational costs for wastewater treatment are
associated with (1) the operation and maintenance of the wastewater
treatment facilities, and (2) the hauling and disposal of sludge. Daily
costs for the 1974 tomato canning season are summarized in Tables 12 and
13. In reviewing Tables 12 and 13, it can be seen that one-half of the
daily operating expenses are associated with the disposal of the waste
solids and sludge.
Annual Cost—An estimate of the total daily cost to Hickmott Foods
including the construction and operational costs is given in Table 14-
For the 1974 tomato canning season, the cost of treatment amounted to
13.0 cents per case of tomato product. On a per can basis, the cost of
wastewater treatment at Hickmott Foods is approximately 0.5 cents.
FUTURE IMPROVEMENTS AND WASTE REDUCTIONS
With the measures Hickmott Foods has instituted to reduce and treat
the wastes generated from canning operations, the company is now in
compliance with state and federal discharge requirements. Nevertheless,
additional steps are being taken or considered to reduce waste loads1 and
treatment and/or disposal costs. These developments are outlined below.
Reduction in Water Usage
Because Hickmott Foods has abandoned its sweet potato and asparagus
operations, daily water usage will be reduced further by shortening the
lengths of belts on which peeled tomato products must travel. This
change will eliminate about 50 gallons per minute of water now used for
belt lubrication. In turn, this will reduce the peak water usage in the
cannery to about 750 to 800 gallons per minute. This quantity is
considered to be the minimum water usage possible to maintain sanitary
conditions. Heightened concern by the US Department of Agriculture over
the issue of machine mold may ultimately result in increased per ton
water usage by Hickmott Foods.
316
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Table 12. SUMMARY OF DAILY OPERATING COSTS FOR WASTEWATER TREATMENT
FACILITIES DURING 1974 CANNING SEASON
Item
Cost, dollars/day"
Power (520 hp x 24 hr x 0.746 kw/hp x 0.02 kwh)
Chemicals (acid, ammonia and phosphate)
Supplies
Testing and monitoring operations (24 hr/day
0 $5.50/hr)
Mechanic-operator (10 hr/day 9 $8.00/hr)
TOTAL
$186
130
50
132
80
$628
Table 13. SUMMARY OF DAILY SOLIDS AND SLUDGE DISPOSAL COSTS
DURING 1974 CANNING SEASON
Cost, dollars/day
Item
Truck driver (1 x 24 hr/day x $7.50/hr)
Truck operation (solids) (4 trips/day x
14 miles/trip x $0.30/mile)
Truck operation (sludge) (20 trips/day x
20 miles/trip x $0.35/mile)
Solids disposal fees (4 loads/day x $3.60/load)
Sludge disposal fees
Discing tractor and operator (1 x 16 hr/day x
$13/hr)
TOTAL
$180
17
140
14
67
208
$626
317
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Table 14. SUMMARY OF TOTAL DAILY COST FOR WASTEWATER TREATMENT
DURING 1974 TOMATO CANNING SEASON3
Item
Capital cost, dollars/day ($885,500b x 1
Treatment plant operation, dollars/day
Solids and sludge disposal, dollars/day
TOTAL, dollars/canning day
Cost/case,6 cents/case
Cost/can, cents/can
Cost/ ton of raw tomatoes, dollars/ton
,627C/90 day/yr)
Cost
$1,601
628
626
$2,855
13.0
0.5
$4.28
Based on a 90-day canning season.
Capital cost from Table 5.
cCapital recovery factor * 0.1625 (10 yrs @ 10%).
Cost data from Table 6.
eBased on two million cases of number 2% cans.
Based on 60,000 tons.
318
-------
Flow Equalization
In activated sludge systems such as the one employed at Hickmott
Foods, hydraulic surges cause large amounts of mixed liquor solids to be
transferred from the aeration basin to the sedimentation basin in a
short amount of time. If these surges are sustained and are of large
enough magnitude, a deterioration in effluent quality can result as the
sludge blanket builds up. With the high aerations solids employed at
Hickmott Foods, increasing the sludge return rate does not effectively
draw down the sludge blanket because of the very low settling velocity
of the mixed liquor at a concentration of 10,000 milligrams per liter
TSS. To reduce the impact of the flow surges, the top 18 to 24 inches
of the aeration basin is to be used for flow equalization. A floating
weir will be used to maintain a constant flow to the sedimentation basin
regardless of the water level in the aeration basin.
Solids Disposal
Currently, all solid and sludge wastes must be hauled away for
disposal. As long as nearby disposal sites are available, this method
is cost effective. If, however, the present system proves to be
unworkable, then further sludge dewatering must be considered. Because
a large amount of concentrated carbonaceous waste is produced, the use
of a pyrolysis process to produce activated carbon is now being
evaluated by personnel from the Jet Propulsion Laboratory of the
California Institute of Technology. The production of a useful by-
product that can be sold to nearby industries would reduce otherwise
prohibitively high operating cost for this method of sludge processing.
Peel Waste Recovery
At present, about 120 tons per day of tomato constituents are lost
as caustic peeling sludge. Dow Chemical Company, in cooperation with
USDA-WRRC and NCA conducted a test run on September 26, 1974 at Hickmott
Foods to investigate the feasibility of recovering the tomato peeling
sludge after acidification as products. The flow scheme incorporated in
these tests is shown in Figure 6. The quality of the puree made from a
1:1 blend of acidified caustic peeling sludge and fresh crushed tomatoes
was judged to be good with respect to both flavor and appearance by NCA.
The quantities of acid required to lower the pH value of the caustic
juice was kept to a minimum by operating the peelers at 8 percent
caustic. Further studies are being conducted by USDA, Dow, NCA and EPA
to establish whether the method can become accepted cannery practice.
The main areas of concern include (1) pesticide residuals, (2) wetting
agent carryover, and (3) chemical by-product formation. If this peel
319
-------
PEELING
SLUDGE
(pH 11.5- 12.2)
1
SOLID WASTE
PULPER - FINISHER
WASTE PEELING JUICE
FOOD GRADE
MIXER
fc
HYDROCHLORIC ACID
WASTE NEUTRALIZED
PEELING JUICE
SURGE TANK
• pH PROBE
pH ADJUSTMENT TANK
ffff 4.2)
•pH PROBE
STORAGE TANK
NEUTRALIZED PEELING JUICE
TO HOT BREAK
Figure 6. Flowsheet for proposed recovery of waste peeling sludge.
320
-------
recovery scheme can be proven to be safe, Hickmott Foods will be able to
recover an additional 4 tons per hour of usable tomato material, reduce
its waste loss from 16 to 6 percent, and cut the number of gallons of
sludge that must be hauled for disposal by one-half.
Raw Product Transportation
Hickmott Foods has also contemplated the installation of bulk tub
dumping facilities (boxes are now used). However, based on preliminary
studies it was found that when ripe peeling tomatoes are stacked 30 to
36 inches high, the bottom one-quarter by weight are broken or cracked.
In a plant such as Hickmott where over 50 percent of all the tomatoes
are peeled, this amount of damaged product and extra waste cannot be
tolerated.
ACKNOWLEDGEMENTS
The authors thank the owners and management of Hickmott Foods,
Inc., for their conern for the environment and their willingness to try
alternative methods and equipment for wastewater management.
321
-------
REFERENCES
1. American Public Health Association. Standard Methods for the
Examination of Water and Wastewater. 13th edition. 1971.
2. Tchobanoglous, G. Investigation and Modification of Wastewater
Management Facilities. A report prepared for Hickmott Foods, Inc.,
Davis, California. June 1974.
3. Wood, D. K, and G. Tchobanoglous. Trace Elements in Biological
Waste Treatment with Specific Reference to the Activated Sludge.
Presented at the 29th Annual Industrial Waste Conference, Purdue
University, Lafayette. May 1974.
322
-------
PILOT-SCALE TREATMENT OF BRINED CHERRY WASTEWATERS
A. F. Maul din*
B. W. Hemphill*
M. R. Soderquist*
D. W. Taylor*
E. Gerding**
J. Ostrin***
INTRODUCTION
In the manufacture of maraschino and glacg cherries, the fruit is
first leached in a sulfur dioxide-calcium chloride-water brine. From
there, the fruit is processed. Unit operations include stemming,
sizing, pitting and packing. The process is diagrammed in Figure 1.
The wastewaters are characterized by low pH's and high levels of
biological oxygen demand (BOD) and sulfur dioxide.
This paper describes a two-phased investigation of the treatability
of these wastewaters by aerobic biological processes. The first phase
consisted of a bench-scale study at Aqua Tech Laboratories, Inc., in
Portland, Oregon in May 1974. In this study, the feasibility of the
oxidation of free and combined sulfur dioxide to sulfate under aerobic
conditions was demonstrated. In the second phase, a 7,000 gallon pilot
plant was erected on-site at The Dalles Cherry Growers, Inc., at The
Dalles, Oregon. The system was operated in an aerated lagoon mode for
four months, then in an extended aeration mode with complete sludge
recycle for three weeks.
*Environmental Associates, Inc., Consulting Scientists and Engineers,
Corvallis, Oregon.
**The Dalles Cherry Growers, Inc., The Dalles, Oregon.
***Stadelman Fruit, Inc., The Dalles, Oregon.
323
-------
V
BRINE MAKEUP
\
f
DEWATER
KEY:
PRODUCT FLOW
BRINE FLOW
WASTEWATER
FLOW
Figure 1. Brined cherry processing flow diagram.
324
-------
METHODS AND RESULTS
Bench Scale SOa Conversion Study
Although in the brined cherry industry efforts are made to conserve
brine, a certain amount does enter the plant waste stream, resulting in
sulfur dioxide (SOa) concentrations typically in the range of 200 to 300
milligrams per liter. In response to conern over the chemical and
environmental effects of the SOa, the previously-mentioned bench scale
study was performed.
Two Plexiglass units of approximately 4 liters each were charged
with a 1:25 dilution and a third unit with a 1:30 dilution of
concentrated spent cherry brine. All units were seeded with raw sewage.
Two units (one each at 1:25 and 1:30) were aerated with the pH initially
adjusted to 6.1, and the third was aerated at an initial pH of 4.6,
which is typical of the combined wastes emanating from the processing
plant. After six hours, the pH in the first two units was further
adjusted to 6.6. All of the units were then allowed to seek their own
pH level. The units were monitored for pH and for concentrations of
free and combined sulfur dioxide (SOa, HSOs" and S03E) and sulfate
(SO*8).
The results of the study are depicted graphically in Figures 2 and
3. On Figure 2 appear the results using dilutions of 1:25 and 1:30 with
pH adjustment. On Figure 3 appear the results of the test on the third
unit, with a 1:25 dilution and no pH adjustment.
As can be seen from Figure 2, the conversion of SOa and HS03" to
SOiT was essentially complete after five days of aeration when the pH
was adjusted initially. Without the benefit of pH adjustment, this
conversion still took only six days, as shown in Figure 3.
The following presents the results of a sulfur mass balance on the
system in Unit A (1:25 dilution):
Initial sulfate in brine = 12 mg/1 as SO*
Initial total sulfur dioxide = 240 mg/1 as SO-*
Total sulfur in untreated brine = 252 mg/1 as SO*
325
-------
CO
to
O3
pH adjusted to 6.1
pH adjusted to 6.6
DAYS
Figure 2. Aeration with pH adjustment.
(25x and 30x dilution; seeded cultures)
-------
w
to
200 —
180 —
160
140 —
I 120-
N
8 100 —
° 80 —
60 —
40 •
20—|
0 •
4.6
pH - 4.9
pH - 5.6
I
4
DAYS
I
6
Figure 3. Aeration without pH adjustment.
(25 x dilution; seeded culture)
-------
After five days of aeration:
Sulfate in mixed liquor = 250 mg/1 as SO*
Total sulfur dioxide in mixed liquor = 0 mg/1 as SO*
Total sulfur in mixed liquor = 250 mg/1 as SO*
This indicates that virtually all total free and combined sulfur
dioxide was converted to sulfate during the aeration process. It is
significant to note that very little SOa was released to the atmosphere
during that process. This finding is consistent with the known
relationship between free and combined sulfur dioxide as discussed by
Payne et al.,1 wherein it is indicated that virtually no free gaseous
S02 exists in solution above a pH of 4.4 and that loss of excessive
amounts of S02 to the atmosphere does not occur above a pH of 2.5.
Since the stripping action of the air would be a function of the
availability of free S02s the above results are realistic.
Pilot Plant Study
Satisfied with the results of the bench-top study, the
investigators began an on-site pilot-plant study at The Dalles Cherry
Growers, Inc., plant. Figure 4 shows the basin equipment and piping
layout for the pilot plant. The raw wastewater was pumped from an
underground sewer to a distribution box that delivered a predetermined
constant flow to the aeration tank and returned the excess flow to the
sewer through an overflow pipe. The 7,000 gallon aeration tank
contained a one-horsepower floating aerator to provide oxygen and
completely mix the tank contents. The aeration tank liquid (mixed
liquor) was transferred by gravity to a 2 foot by 2 foot by 4 foot deep
settling tank. Not shown in Figure 4 is the sludge recycle pump and
piping used in the study during the extended aeration mode.
Operation, Sampling and Testing Procedures
The pilot plant study was performed in three series. A description
of these series and the procedures followed for operation, sampling and
testing follow:
Series I—July 11 to July 25. During this period, the plant was
processing only fresh cherries; consequently, no brine was contained in
the wastewaters. The pilot plant was operated in an aerated lagoon mode
(no sludge recycle) at a 5-day retention time.
328
-------
SETTLING
TANK
to
Influent
Distribution Box
Surface Area
4 sq. ft.
Treated
Effluent
•
__ i ___ Row Influent I
INFLUENT PUMP
(V_30 Sewer
_V Rm
Floating
I HP.
Aerator
Reinforced Fiberglass
12-0" Top Diam.
l'-0" Bottom Diam.
Raw Wastewater
Figure 4. Pilot plant diagram.
-------
To start the biological system efficiently, the aeration tank was
seeded with activated sludge from The Dalles wastewater treatment plant.
After dilution the mixed liquor suspended solids level was approximately
2,000 milligrams per liter.
The wastewater influent flow rate was set at 1.0 gallons per minute
and operated for 24 hours per day, corresponding to the processing plant
operation (including a 6-hour cleanup shift). The wastewaters were
assumed to be nutrient deficient, so nutrients were added in the form of
urea (46 percent N) and ordinary garden fertilizer (6 percent N, 10
percent PaOs, 10 percent SO
-------
Table 1. SCHEDULE OF ANALYSES FOR SERIES II AND III
t,:
Test
BOD, unflltered
BOD, filtered
COD, unfiltered
COD, filtered
Suspended solids
Volatile suspended solids
PH
Sludge volume index
Sulfur dioxide
Sample station3
Influent
D
W
D
W
W
W
D
-
D
Mixed liquor
-
D
-
D
D
D
D
D
-
Effluent
D
W
D
W
D
D
D
-
D
*D = Daily
W = Weekly
331
-------
phosphorus and total Kjeldahl nitrogen, and on the mixed liquor
temperature. As in Series I, most of the tests were done in the Cherry
Grower's laboratory, with samples occasionally being sent to Aqua Tech
to provide checks on accuracy and to perform the more complex analyses.
Steady-state conditions were judged to have occurred when the mixed
liquor suspended solids level remained relatively constant for several
days. In addition to evaluation of steady-state conditions, the
resistance of the system to shock loadings was investigated. These
loadings included surges of organics, flow and chlorite wastewater from
the secondary bleaching process.
Results of Pilot-Plant Study
Table 2 lists the results of Series I through III at steady-state
conditions. The data shown that BOD removals in excess of 98 percent
were achieved in all of the series. Oxidation of sulfur dioxide in
Series II and III was virtually complete in all of the trials and the
system contained enough natural buffering capacity to consistently
provide an effluent pH near 7.0 without chemical neutralization of the
wastewaters.
The data confirm the assumption that the waste is deficient in
nitrogen and phosphorus, with a BOD:N:P of approximately 100:1.4:0.3,
compared to a ratio of 100:5:1 considered adequate for good biological
growth.3
Figure 5 shows the effect of hydraulic retention time on the sludge
volume index (SVI) for the aerated lagoon system. The SVI had a value
of 190 at 9.7 days retention time and over 500 for the other trials. A
value of 860 was recorded in Series I. As shown in Table 2, the
food:microorganism ratio (F:M) varied from 0.21 at 18 days retention
time to 0.45 at 4.5 days. The best settling sludge developed at a
retention time of 9.7 days, at which the F:M ratio had a value of 0.31.
This observation is consistent with the statement in Metcalf and Eddy1*
that good settling characteristics result from mean cell residence times
of 6 to 15 days (for the aerated lagoon mode, the mean cell residence
time is equivalent to the hydraulic retention time).
The high values of SVI were observed to be a result of filamentous
bulking, as discussed by Pipes.5 Microscopic examination of the mixed
liquor revealed the presence of significant numbers of filamentous
organisms. Their development may have been linked to the fact that the
wastewater had a high concentration of soluble carbohydrate materials,
an environment in which filamentous organisms have an advantage. In
some cases, bulking has been seen to result from conditions such as Tow
332
-------
Table 2. PILOT PLANT PERFORMANCE DATAa
Hydraulic retention
time, days
BOD5, mg/1
COD, mg/1
Suspended solids, mg/1
TKN, as N, mg/1
POij, as P, mg/1
PH
Sulfur dioxide, mg/1
Sludge volume index,
ml/gm
Food :mi croorgani sm
Temperature, °C
Series I
4.5
I
1,510
2,880
120
16
3.8
-
-
Ed
8
94
70
8
2.6
-
-
860
0.45
19
Series IIb
4.8
I
2,910
5,200
140
51
9.9
4.7
350
Ed
40
200
40
12.4
3.9
7.1
Trace
540
0.38
13
9.7
I
2,575
3,860
130
39
10.0
5.4
Trace
E
41
230
110
12.3
7.9
7.0
Trace
190
0.31
17
18.0
I
2,500
3,700
130
-
-
4.9
240
Ed
31
110
29
-
-
7.2
Trace
510
0.21
8
Series IIIC
4.8
I
1,870
2,800
110
-
-
5.2
Trace
Ed
19
100
-
-
-
7.0
Trace
800
0.43
6
CO
Co
co
ll
Influent; E = Effluent
Aerated lagoon system,
GExtended aeration.
dSupernatant of mixed liquor settled artificially in laboratory.
-------
10001
800
x
LJ
O
z
UJ
1
UJ
O
O
V)
600
400-
200
0
10
15
20
HYDRAULIC RETENTION TIME, DAYS
Figure 5. Sludge volume index versus retention time for
aerated lagoon system.
334
-------
dissolved oxygen levels in the aeration tank, adverse pH or insufficient
levels of nutrients.5 None of these conditions were believed to exist
in the pilot plant, however.
In Series III, an attempt was made to control the loading rate by
recycling sludge back to the aeration tank in an extended aeration mode.
The object was to increase mixed liquor concentration, thereby adjusting
the F:M ratio to obtain a level at which good settling would occur. The
system was operated at a retention time of 4.8 days.
The results obtained were not encouraging. The SVI was observed to
be about 800. At this level, it was not possible to achieve separation
or concentration of the sludge in the settling unit. Considerable
sludge was lost in the effluent, rather than being recycled. One sample
collected from the settling tank overflow had a suspended solids
concentration of 1,850 milligrams per liter with corresponding BOD of
over 1,000 milligrams per liter. The conclusion of the processing
season precluded further attempts to control the process.
Evaluation of Shock Loadings
In addition to the evaluations already discussed, the resistance of
the aerated lagoon system to shock loadings was investigated. These
loadings included organics, flow and chlorite wastewater from the
secondary bleaching process.
An organic shock load occurred on October 17 when plant operational
problems resulted in the spillage of a large amount of concentrated
brine from the pitting process. The pilot plant was operating at a 4.8
day retention time. The spill caused the influent BOD composite to
increase to approximately 1.5 times its normal level resulting in an F:M
ratio of 0.70. This caused the sludge volume index to increase from 270
to over 600. Such a response is not uncommon in biological treatment
systems, especially when the wastewater is high in soluble BOD.5
To simulate a hydraulic overload, the influent pumping rate was
increased to four times the normal flow while the strength of the
wastewater was unchanged. The systems response was favorable. That is,
efficient treatment was maintained along with a beneficial effect on the
SVI.
Of particular interest was the response of the system to the
chlorite wastes from the secondary bleaching tank. During secondary
bleaching, cherries still containing blemishes after the initial brining
step are held in a solution that is approximately 0.75 percent sodium
chlorite. Depending upon conditions in the tank, bleaching ranges from
335
-------
several days to weeks and results in a blemish-free product. When
bleaching is complete, the solution is leached from the cherries with a
continuous stream of fresh water. Since sodium chlorite is a powerful
oxidant, concern existed regarding the toxic effects this waste might
have on the treatment system. A 7,000 gallon tank containing the
chlorite solution was leached on November 11. The pilot plant influent
was observed to immediately change from its usual pale yellow to a
bright yellow-green color. Analysis of grab samples revealed that the
primary shock loading occurred within the first two and one-half hours.
The chlorite concentration peaked at 170 milligrams per liter after 30
minutes. The pH of the wastewater was down about one unit from its
normal value of 5.0.
The introduction of chlorites appeared to have little effect on the
performance of the biomass in the aeration tank. Efficient treatment
was maintained during and after the chlorite loading. An immediate
reaction was a reduction in the SVI from 530 on the 10th to 255 on the
13th. The use of an oxidizing agent, such as chlorine, in controlling
bulking sludge has been well documented, and it appears that the
bleaching waters may actually be of benefit to the treatment system.
DETERMINATION OF KINETIC COEFFICIENTS
Substrate Removal
A mathematical model commonly used to describe the treatment
efficiencies in an aerated lagoon system is that which assumes first-
order kinetics":
e ' T
S
where Se = effluent substrate concentration, mg/1
S0 = influent substrate concentration, mg/1
K = first-order substrate removal rate, day"1
t = hydraulic retention time, days
336
-------
K, the removal rate, has been noted to depend on temperature as
given by the expression1*:
KT - K20x0T-20 (2)
where KT = reaction rate at T degrees C, days"1
K20 = reaction rate at 20 degrees C, days"1
0 = temperature activity coefficient
T = temperature, degrees C
Values of Kj computed from Table 2 are plotted against temperature
in Figures 6 and 7, based on BOD and COD, respectively.
From Figure 6, the following formulation based on BOD, is derived:
KBQD = 14.5 x 1.085(T " 20) (3)
From Figure 7, using COD values, equation 4 is obtained:
"COO,. • 4.61 X 1.07
-------
2O
10
1
UJ
ce
r- 2
©
8
©
r=.62
©
KBOD(T)S|4-5XK085
T-20
10 12 14 16
TEMPERATURE, °C
18
20
Figure 6. BOD removal coefficient versus temperature.
TEMPERATURE, °C
Figure 7. COD removal coefficient versus temperature.
338
-------
where ^p- = net growth rate of organisms, mass/volume-time
Y = growth-yield coefficient, mass cells/mass substrate
ds utilized
TT- = rate of substrate utlization by organisms, mass/volume-
time
b = decay coefficient, time"1
X = concentration of microorganisms
Rearranging, the following is obtained:
(6)
The term on the left-hand side is equivalent to the inverse of the
hydraulic retention time in a no-recycle system. The term y is
equivalent to the F:M ratio. These two terms are plotted against each
other in Figure 8 and the values of Y and b determined from a regression
line fit. These values are:
Y = 0.62 mg cells/nig BOD utilized
b = 0.06 days'1
DISCUSSION
The values of the coefficients given in the above section were
computed using the values of total BOD and COD as given in Table 2.
Except for Series I, the system was run on a non-continuous feed basis,
that is, the wastewater was supplied to the system only 12 hours per
day. Effluent samples were taken after the system was aerated without
feed for 12 hours. The values obtained may therefore differ from those
obtained in a continuous system.
CONCLUSIONS
1. The wastewaters from the brined cherry pitting process are highly
treatable in an aerobic biological treatment process.
339
-------
.25T
20-
.15-
.2
'e
JO-
'S .05
«
"05-
"JO^
Least squares fit
Y=0.62
©
b= 0.06 Days
-I
•4-
.2 .3 .4
Food: Microorganism Ratio, Days"'
0.06
.5
Figure 8. Determination of growth-yeild coefficient Y and
decay coefficient b.
340
-------
2. The system effluent will be virtually free of sulfur dioxide and
have a pH near neutrality without the need for chemical treatment.
3. The most significant problem to be faced is that of operating the
system so that good sludge settling characteristics are maintained.
4. The optimum retention time appears to be about ten days in an
aerated lagoon mode.
5. The aerated lagoon system appears to be susceptible to upset by the
introduction of organic shock loading.
6. Hydraulic and chlorite shock loadings should not cause upsets, with
the latter being of possible benefit.
ACKNOWLEDGEMENTS
The authors wish to express thanks to the staffs of Stadelman
Fruit, Inc., and The Dalles Cherry Growers, Inc., both of The Dalles,
Oregon, for their cooperation throughout the study and for their
willingness to release the data contained in this report. Thanks are
also expressed to the Pacific Northwest Environmental Research
Laboratory of the US Environmental Protection Agency, Con/all is, Oregon,
for their loan of equipment used in the pilot plant.
341
-------
REFERENCES
1. Payne, et al. The Chemical and Preservative Properties of Sulfur
Dioxide Solution for Brining Fruit. Agricultural Experiment
Station, Oregon State University, Corvallis. Circular of
Information 629. 1969.
2. American Public Health Association, Inc. Standard Methods for the
Examination of Water and Wastewater. 13th edition. New York.
1971.
3. Eckenfelder, W. W., Jr. and D. J. O'Connor. Biological Waste
Treatment. Pergammon Press. 1961.
4. Metcalf and Eddy, Inc. Wastewater Engineering. McGraw-Hill.
1972.
5. Pipes, W. 0. Bulking of Activated Sludge. Advances in Applied
Microbiology. 9:185. 1967.
342
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CHARACTERIZATION AND POTENTIAL METHODS FOR REDUCING
WASTEWATER FROM IN-PLANT HOG SLAUGHTERING OPERATIONS
Donald 0. Dencker*
David L. Grothman**
Paul M. Berthouex***
Lawrence J. P. Scully****
James E. Kerrigan*****
INTRODUCTION
The purpose of the project is to determine physically the waste
loads and their characteristics generated by the subprocesses employed
in a typical hog slaughtering operation. After waste stream
characterizations, our intent is to make selected in-plant modifications
which will achieve one or more of the following objectives:
1. Reduce water use,
2. Reduce and/or prevent product loss to sewers, and
3. Reuse wastewater.
Due to stringent US Department of Agriculture (USDA) inspection
requirements, potential for reuse is greatly limited.
Until recently, almost all emphasis in handling meat industry
wastewaters had been directed toward end-of-pipe treatment. However, it
has been apparent to those familiar with the industry that the potential
exists for achievement of significant wasteload reductions through in-
plant measures.
*General Sanitary Engineer, Oscar Mayer and Company, Madison, Wisconsin.
**Project Engineer, Oscar Mayer and Company, Madison, Wisconsin.
***Associate Professor, Department of Civil and Environmental
Engineering, University of Wisconsin, Madison, Wisconsin.
****Research Assistant, Water Resources Center, University of Wisconsin,
Madison, Wisconsin.
*****Project Engineer, AMAX, Inc., Denver, Colorado; formerly Associate
Director, Water Resources Center, Madison, Wisconsin.
343
-------
These in-plant measures can be designed into a new plant, but they
present numerous implementation problems in existing facilities.
The enactment of the Federal Water Pollution Control Act Amendments
of 1972 has provided emphasis on in-plant measures as "Best Available
Technology" required to be met by July 1, 1983. Effluent guidelines and
standards promulgated by the US Environmental Protection Agency (EPA)
envision extensive in-plant control of pollution losses. The recently
published Red Meat Industry Development Document1 makes reference to
water control systems and procedures to reduce water use by about 50
percent.
Hog slaughtering operators should be interested in the results of
this present study in that approximately 50 percent of these facilities
are direct dischargers to public waters, while most of the remainder are
subject to the public facility user charge and industrial cost recovery
provisions of the 1972 Act (Public Law 92-500).
STATUS OF THE MEAT INDUSTRY
The meat industry is generally grouped in the food product category
classification. The 1973 employement data for comparison of the entire
food industry and with all manufacturing is shown in Table 1.
A breakdown by species of the total federally inspected slaughter
in 1974 is shown in Table 2.
Table 3 shows the 1974 slaughter as related specifically to hogs.
Oscar Mayer and Company, Inc., in 1974 slaughtered over 6 percent
of the total federally inspected hogs, and the plant included in this
study had a kill slightly over 5 percent of all federally inspected
hogs.
PROJECT GOALS
The meat industry was identified in the 1972 Act as one of 27
industries requiring standards of performance for new sources (Section
306). The listed industries, including "meat product and rendering
processing", have also been covered by effluent guidelines and standards
issued by the EPA. The Federal Register on February 28, 1974, published
"Best Practicable Control Technology" (July 1, 1977) and "Best Available
Technology" (July 1, 1983) effluent requirements for the red meat
344
-------
Table 1. EMPLOYMENT IN THE MEAT INDUSTRY, FOOD
INDUSTRY, AND ALL MANUFACTURING IN 19732
Industry
Meat packing (SIC2011)
Meat processing (SIC2013)
MEAT TOTAL
All food
All manufacturing
Total
employees
172,500
59,000
231,500
1,736,300
19,820,000
% of all
manufacturing
0.9
0.3
1.2
8.8
100.0
345
-------
Table 2. FEDERALLY INSPECTED SLAUGHTER IN 1974s9
Species
Cattle
Calves
Hogs
Sheep &
lambs
TOTALS
Head killed,
USDA inspection
33,318,000
2,354,000
77,070,000
8,556,000
121,298,000
Avg. live wt.,
Ibs
1,052
211
245.2
105
Total LWK,
millions of Ibs.
35,050.5
496.7
18,898.8
898.4
55,344.4
% Total
LWK
63.4
0.9
34.1
1.6
100.0
Federal inspection includes over 90% of all species slaughtered.
Table 3. SLAUGHTER OF HOGS IN 1974"
Slaughtering site
Federal inspection
State inspection
Farm slaughter, est.
TOTALS
Head killed
77,070,000
4,705,900
1,050,000
82,825,900
Percent of total
93.0
5.7
1.3
100.0
346
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industry. These are the federal limits which are applicable to
effluents from existing hog slaughtering operations.
The first objective of this project is to see what can be
reasonably accomplished in a typical large hog slaughtering operation
without major alterations to the plant, and with little or no hindrance
to the productive output. This need to reduce in-plant waste while
maintaining the usual production rate and quality requires the
cooperation of the operating personnel involved and backing of
management. To this end, project personnel have diligently kept line
supervision informed, and meetings are held to obtain the opinions and
recommendations of the people involved in any proposed change.
Other factors which are considered in project decisions are the
health and safety of employees, cost effectiveness, and the
measurability of any change.
The second goal of this project is to make the subsequent in-plant
treatment task easier and less costly, especially as to what is required
to comply with EPA Best Practicable Control Technology and Best
Available Technology effluent requirements.
DESCRIPTION OF PLANTS
The Madison plant where most of the study was carried out was built
originally in 1917 by the Farmer's Cooperative, and was purchased by
Oscar Mayer and Company in 1919. Since its purchase, the plant has
expanded more" than 14 times and now includes a modern meat processing
plant, spice processing and plastic production as well as a 1,000 head
per hour hog kill and an 80 head per hour beef kill.
The Davenport plant was purchased in 1946 from Kohr's Packing
Company. Since its purchase it has been greatly renovated and expanded.
The plant combines a 750 head per hour hog slaughtering and butchering
facility with a large modern ready-to-eat processed meat plant.
Beardstown was built in 1967 as a hog slaughtering and butchering
facility with a capacity of 750 hogs per hour. Since the original
construction, the plant has been increased in size by 40 percent to
provide additional room for ham canning and other operations.
347
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Madison Hog Kill Process
Hog slaughtering is an assembly line, or rather a dis-assembly line
process (Figure 1). In Madison, the hogs are driven one at a time into
a conveyorized carbon dioxide tunnel where they are anesthetized. The
unconscious hogs are then dropped onto an inclined steel slat conveyor
which has a stainless steel trough running along one side of it. The
hogs are placed with their necks over this trough and a knife is used to
cut the jugular veins and carotid arteries. The blood which is
collected is pumped to a blood processing area where it is dried for use
as animal feed. When the hog carcasses reach the top of the inclined
bleed conveyor, they drop off into a long shallow scald tank filled with
140 degree F water and a scald aid. The carcasses are pushed the length
of the tank by means of mechanical "dunkers". Total scald time is about
five minutes. From the scale tank, the carcasses are conveyed into a
dehairing machine where steel tipped rubber paddles strip the hair from
the carcasses. The carcasses are constantly lubricated and the hair is
carried away by recirculating hot water in the machine. The hair and
toenails are removed and sometimes saved and sometimes discarded. From
the dehairing machine, the carcasses are hung on gambrels inserted
behind the achilles tendon and are hung on a live chain.
The carcasses are then dipped into a 300 degree F rosin tank and
coated with rosin. The rosin is then water cooled and stripped off,
taking with it some of the hair not removed in the dehairing machine.
After the rosin stripping, there is a gas flame singer, a set of water
lubricated scrapers and a series of workers who shave off any remaining
hair before the carcasses go through a deluging shower which carries off
all loose soil and hair. Once the carcass has passed this point, any
remaining hair or soil has to be removed by excision. From this point,
a series of workers cut off the eyelids and sever the head from the
body, leaving it hung by a strip of flesh, and USDA inspectors check the
salivary glands for infections. The brisket is split, the aitchbone is
split, and the bladder (and uterus, if present) are removed. The anus
is cut around and the abdomen is opened and the viscera removed and
placed on a conveyor. The carcass is spilt through the backbone, the
kidneys are freed, and some internal trimming is done before the
carcasses are given a final inspection by a USDA inspector. The kidneys
are removed, the head is removed, the internal fat is stripped out and
scraped, the stick wound in the neck is washed, and the carcass is
weighed and sent to the cooler to be held for further breakup the
following day.
The viscera, after being inspected by a USDA inspector, are
separated with the heart, lungs, liver, pancreas, caul fat, spleen and
stomach being removed either for edible product, drug manufacturing or
animal food. The large and small intestine and all condemned viscera
348
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co
Figure 1. Process flow sheet.
-------
are cleaned and sent to a cooker where they are processed for grease and
animal feed. The muscles from the cheeks and scalp are removed from the
head and the skull is split open and the hypothalamus and pituitary
glands are removed and quick frozen. The skull and jaw bones are ground
up and processed into animal feed.
Madison Water Supply
The water supply for the Madison plant is supplied both by wells on
the property and by purchased city water. Potable water is required in
all washing and cleanup operations, and 180 degree F water is used for
viscera pan washing and other applications the USDA deems necessary.
Madison Waste Collection System
Madison's wastewater collection is by means of four separate
systems: (1) clear water which is cooling water and roof drains, (2)
sanitary drains from toilets, (3) grease, containing industrial
wastewater, drains from the kill floor, cutting floor and processing
plant, and (4) manure, containing industrial wastewater, drains from the
stockyards, dehairing machine and stomach washer.
The clear water drains discharge to a city storm sewer and the
sanitary sewage is sent directly to a city sanitary sewer. The grease
and manure containing wastewater systems go through primary and
secondary treatment on the premises before being discharged to an
interceptor sewer of the Madison Metropolitan Sewage District.
Variances at Davenport and Beardstown
Davenport's kill floor is almost the same as Madison's except for a
few differences in physical layout and brands of equipment used. Like
Madison, Davenport's water is supplied both from the city and from
private wells. Unlike Madison, they do no secondary treatment of plant
wastes; suspended solids are removed by screening and grease flotation.
The pretreated effluent is sent to the City of Davenport sewage
treatment plant.
In Beardstown, the hogs are electrically stunned and shackled by
one hind leg and bled over a blood collecting pit rather than on a
conveyor. In Beardstown, the rosin dip is not used.
All of Beardstown's potable water supply comes from three wells
located on the plant property.
350
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Beardstown's clear water runoff is conveyed from the plant site in
a drainage ditch. The grease and manure containing drainage systems,
after being pretreated to remove suspended solids and grease, are
combined with plant sanitary sewage and are pumped to a series of
anaerobic then aerobic lagoons for final treatment before discharging to
the Illinois River.
PROJECT IMPLEMENTATION
The project goals will be accomplished in three main steps: (1)
characterize water use and waste generation, (2) plan, design and
install process changes, and (3) recharacterize waste generation to
evaluate and quantify benefits.
Special attention is given to locations on the kill floor which
have the greatest potential for reduction of pollution loads through
changes in work procedures, equipment, and process redesign. Care must
be taken to insure that these changes do not interfere with the rate of
production, the quality of the product, or the health and safety of the
workers.
WASTEWATER CHARACTERIZATION
The first step in the study was to characterize the waste flows and
loads generated on the kill floor. Wastes range from meat scraps to
whole blood to drinking fountain water, and are generated in great
variety depending upon location on the kill floor. The initial
characterization is designed to quantify in sufficient detail the point
discharges representing nearly all the pollution. The characterization
study will then be used to direct attention to areas where profitable
changes can be made and to provide a datum for later evaluation of the
changes.
General Observations and Process Flow Sheet
The process flow on the kill floor was shown in Figure 1, which
indicates hog carcass movement, by-product generation points, and
sources of wastes. The waste collection system for the kill floor is
shown in Figure 2 and includes four types of drains: hasher-washer
drains, blood recovery drains, grease water drains, and manure water
drains. The process flow sheet and the collection system were studied
351
-------
[SHAVERS]
Figure 2. Madison kill floor drains.
352
-------
Scale: %" = I'D"
KEY
S WASWCR CHUTE.
DRAIN
R OftAIN
wATtR D«*i%
ClNTER LINE - KILL Cn
353
-------
and the following sampling points in the Madison plant were selected to
adequately describe the waste:
1. Bleed area floor drain 9.
2. Bleed conveyor blood drain 10.
3. Bleed conveyor wash lla.
4. Scald tank lib.
5. Dehair floor drain lie.
6. Dehair wash* 12.
7. Hair wash drain* 13.
8. Rail polisher 14.
*Not shown in Figure 2.
Carcass shower
Hasher-washer
Stomach washer
Neck washer
Head washer
"660" grease drain
Center grease drain
"330" grease drain
Sampling Methods
Some sample points were adaptable for automatic sampling (ISCO
samplers were used), such as rinse cabinets and the bleed area. Wastes
laden with heavy solids or hair were samples manually.
The location of the kill floor at the Madison plant caused several
problems in sampling and making flow measurements. It was important to
locate sampling points where the waste was well mixed so samples would
be representative, and it was necessary to find locations to isolate
waste contributions from adjoining areas. The three main grease drains
were sampled from ports installed one story below the kill floor. The
manure drain from the dehairing-scald tank process was sampled several
stories below the kill floor. The Oscar Mayer staff played the major
role in designing and installing special sampling facilities.
Parameters Measured
The following parameters were measured on all samples: total
solids, total volatile solids, suspended solids, suspended volatile
solids, total Kjeldahl nitrogen, total organic carbon, BOD5 and COD.
Grease, pH and total carbon were measured on a substantial portion of
the samples as well.
All analyses were done according to the standard methods and
accepted EPA methods. Quality control was checked twice by EPA
standards evaluation with satisfactory results. Internal checks using
split samples and duplicate samples are also used.
354
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Flow Measurement
The individual quantification of the several hundred point sources
of water on the kill floor is an impossible task. The piping
distribution system which is separated to deliver three temperatures of
water, is an intricate maze. The installation of water meters was only
feasible on certain single high volume discharges. Those areas included
dehairing machine, railpolisher and carcass shower. Several small
discharges were measured with the bucket and stopwatch technique.
However, the characterization of the flows combined in the various
drains required the use of lithium chloride dilution technique. This
technique has proven valuable in places where other flow measurement
techniques cannot economically be implemented. The lithium chloride
does not adsorb onto particles and the lithium can be measured in
concentrations as dilute as 0.01 milligrams per liter with atomic
absorption. The combination of all these flow measurement techniques
has been used to measure flows for both production and cleanup shifts.
Data Analysis
Estimation of the pollution load requires careful consideration of
the limitations and accuracy of the measurements to be used. This is
particularly important for this study where the original load will be
compared to the reduced pollution load after changes have been made.
For this study, parameters for each day of samples were estimated
in terms of an average, and characterized with a standard deviation and
a standard error. For each sample point the concentration data was
combined with the flow data to estimate the total load from that point.
Each point load was compared to the total load to determine its percent
of the total load. Those points which seem to be responsible for the
majority of the loadings are to be emphasized in the reduction phase of
the study. Table 4 summarizes the BOD loadings from the hog
slaughtering operation. Loadings are expressed as pounds of pollutant
per 1,000 pounds live weight kill, a standard industry common
denominator.
Sources and processes of major importance were then studied to
identify poor operating procedures, sources of a particular waste, and
overall reduction potential.
Data for the cleanup period is also being collected. This data
will appear in the final report.
355
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Table 4. SUMMARY OF INITIAL CHARACTERIZATION OF THE HOG SLAUGHTERING FLOOR FOR THE MADISON
PLANT. PRODUCTION SHIFT VALUES ARE BASED ON AN AVERAGE KILL OF 1,253,000 LBS PER DAY.
co
01
Oi
Sample point
1. Bleed area floor drain
2. Bleed conveyor blood
drain
3. Bleed conveyor wash
4. Scald tank
5. Dehair floor drain
6. Dehair wash drain
7. Hair wash drain
8. Rail polisher
9. Carcass shower
10. Hasher-washer drain
lla. Stomach washer
lib. Neck washer
lie. Head washer
12. "660" grease drain
13. Center grease drain
14. "330" grease drain
TOTAL
Flow
Gallons/
production
shift
_a
2,550
_c
108,400
_d
_d
10,960
(25,226)e
93,800
12,975 f
(l,330)f
(6,520)9
30,140
40,260
37,890
336,975
Gallons/
1,000 Ibs
LWK
_
2.04
_
86.51
_
8.75
(20.13)
74.9
10.35
(1.06)
(5.20)
24.05
32.13
30.24
268.97
Percent of
production
flow
_
0.75
_
32.1
_
3.2
/
27.8
3.8
-
-
8.9
12.0
11.3
100.0
BOD 5
mg/liter
_
946
.
1,062
1,660
246
264
56
5,860
1,112
3,744
-
204
208
1,235
Pounds/
production
shift
_
20.1
_
960
_
_
24
(11.9)
4,580
119
(41.4)
-
51.3
68.9
389
6,212.3
Pounds/
1,000 Ibs
LWK
_
0.0161
_
0.7662
»
-
0.0193
(0.0095)
3.66
0.095
(0.03309)
-
0.041
0.055
0.311
4.96
Percent of
production
load
_
0.3
_
15.4
_
0.4
-
73.7
1.9
-
0.8
1.1
6.3
100.0
aNo flow during production.
Flows to blood recovery system during production.
cScald tank does not drain during production.
Dehair wash drain and hair wash drain are not part of the kill
elncluded in "660" grease drain total.
fIncluded in hasher-washer drain total.
Included in "330" grease drain total.
floor and exist only when hair is saved.
-------
Establishing Water Quality Requirements for Recycle
Water recycle can play a great role in pollution reduction. An
integral part of this evaluation is the establishment of water quality
criteria at each point for possible water reuse. Many points are
eliminated as candidates for recycled water because the USDA specifies
the use of potable water, but there are a few possibilities. In these
cases the quality required at the use point has to be matched to that of
an effluent stream. For example, if Process A can function with
influent water having 200 milligrams per liter suspended solids then the
effluent from Process B, which has 200 milligrams per liter or less of
suspended solids, is a potential source. Quantities must be matched as
well. This approach is useful in all areas of the plant.
DESIGNING PROCESS CHANGES
A plan for alterations must consider the difficulties involved in
making physical changes or operational changes on the kill floor, and
governmental restrictions which must be satisfied. These factors and
the following points were emphasized when planning changes for this
study.
Excessive Pollution Load Due to Process Design
Some processes inevitably have high pollution loads even with
proper operation. For example, almost all older pieces of equipment
were designed without regard for water pollution abatement. Substitutes
for such processes are needed; these are being examined for productivity
and quality.
Modifications of existing equipment were studied to try and obtain
significant reductions at low cost. These modifications considered the
redesign of spray nozzles and other water distribution mechanisms to
minimize wasted water and the washing of soluble BOD down the drains.
The massive use of water for cleaning purposes in the meat industry
creates excessive amounts of wastewater production. Dry collection of
solids and organic material prior to wet cleaning can considerably
reduce the pollution loading. A new technique being considered is
vacuum cleaning of the kill floor to reduce BOD loadings to the
treatment plant and to increase the input to inedible rendering.
357
-------
Excessive Pollution Load Due to Improper Operation
A second type of change is needed to reduce pollution loads which
are the result of improper operation or inefficient cleaning procedures.
Training personnel to use proper water reduction techniques is an added
supervision task. It is difficult, but critical. More recently the
economic considerations for pollution treatment are forcing new
operating practices to be devised and enforced. Squeeze-to-open valves
are being tried to minimize excessive use of clean water by the
sanitation crew. These values require the crew members to continually
hold the valve open ir. order to obtain water.
Recycle Potential
As mentioned earlier, recycling wastewater within the plant can be
a significant factor in reducing total effluent loadings. Consideration
is being given to using water from a vapor phase condenser to sluice the
hair in the dehairing machine, manure drain and in other similiar
applications.
Governmental Restrictions
A major factor in any pollution reduction story is consideration of
governmental requirements. The USDA regulations are strict in the meat
industry. However, new techniques can be approved by the Technical
Services Division of USDA and installed on a trial basis to evaluate
reductions in pollutant production.
Quality of Product Constraints
Often a particular company will have higher standards of quality
than the USDA restrictions. Implementation of ideas to reduce the
pollution load must not violate these standards of quality. Some new
techniques can be tried on a pilot basis prior to on-line testing.
Close coordination with plant production personnel is essential to a
successful modification of existing production process.
Segregation
A common tool for reducing the pollutant load is segregation and
separate treatment of wastes having special characteristics. A separate
blood drain will greatly aid in reducing overall pollution if this
single drain can be connected to a blood recovery system. Other forms
35b
-------
of segregation, such as grease segregation and clear water segregation
should be considered.
If the waste load can be separated into a low-flow, high-concen-
tration line and high-flow, low-concentration, great savings can be made
in treatment cost. Pretreatment of low-flow, high-concentration lines
will result in an overall lower cost for the final treatment process.
Complete segragation actually begins by not letting clear waters
run over waste solids or wash blood into a drain. The clear water
should be piped directly into the drain and the blood and solids should
be dry collected for rendering.
INSTALLING PROCESS CHANGES
Once the areas which need changes have been chosen the changes must
be designed and installed with a minimum of interruption of production.
*
The proper planning, design, and installation of proposed changes
can be very imporatnt in the overall success of a pollution reduction
study.
Close cooperation at all levels will insure a greater percentage of
successful changes in the plant.
Some important factors considered in design and installation of a
change are proper timing, reliability, the human factor, and
installation.
A design change which will affect production can be accomplished
very smoothly with proper coordination between production personnel.
All materials should be on hand prior to starting the remodeling. A
partially completed change will not help anyone.
Each company has a policy on the amount of money it usually spends
in back-up equipment. A redesigned process which is good for pollution
reduction but has a low reliability factor would cause management to
reject the idea based on operational problems rather than technical
capabilities.
A system that can reduce pollution will become ineffectual if the
people who must work with it are dissatisfied and uncooperative.
Consideration of human behavior is essential. Any new designs should
include ways of minimizing human interference. Automatic controls can
be designed, but they are expensive. A practical design combined with
359
-------
proper staff training and understanding can lead to better results than
complicated and expensive equipment.
Proper installation is important. All necessary governmental
authorization must be obtained and all safety factors must be taken into
account prior to installation.
POTENTIAL IMPROVEMENTS
Based on an analysis of the flows and loads from the various
discharge points shown in Table 4, areas were selected for studying
potential improvements. The sources, problems, and changes under
consideration are listed below (see Figure 2 for floor plan).
1. Source: Stick and Bleed Area
Problem: Overflow of blood from the blood receiver onto the floor
during operation. This blood is washed into the grease drain
during cleanup.
Potential Improvement: This situation can be corrected by
redesigningtReblood receiver to allow for periodic surges of
blood.
i
2. Source: Dehairing Machine
Problem: Presently 40,000 gallons of potable water during
production and 25,000 gallons of water during cleanup are being
used to transport hair to the pretreatment plant or to hair-
washing.
Potential Improvement: Replace the potable water with recycled
water from the vapor phase trolley cleaning or the final carcass
shower. Another alternative would be to handle the hair dry as is
done in one of the other plants.
3. Source: Rail polisher
Problem: Water runs when no hogs are in the railpolisher.
Potential Improvement: Install a micro-switch-operated solenoid
valve to turn off water when no hogs are in the railpolisher.
4. Source: Carcass Shower
Problem: Water runs when no hogs are in the shower, and the
present nozzle system wastes water by spraying water into the space
between the hogs in the conveyor system.
Potential Improvement: Install a switch-operated solenoid valve as
describedforth~irailpolisher. Redesign the nozzle system to
spray only on the hogs and not between them.
360
-------
5. Source: Brisket Breaking-Evisceration
Problem: Large numbers of blood clots and trimmed parts are
dropped onto the floor and into the gutter. Wastewater from
drinking fountains, lavatories and sterilizers wash over this
material and carry soluble BOD and other pollutants to the drain.
During cleanup some of the clots and fine scraps are pushed down
the waste shute to the hasher-washer drain or down the grease
drain. This material ultimately adds up as sewage which must be
treated.
Potential Improvement: The change consists of two steps:
Step One: Route dilute wastewaters directly into drains and
away from areas of scrap and blood clots, and
Step Two: Pick up floor scrap and blood clots with a vacuum
cleaner to increase recovery of inedible scrap and
reduce total pollution load from the kill floor by
keeping the scrap out of the drains.
6. Source: Carcass Splitting
Problem: Bone and meat dust from carcass splitting is washed down
the grease drains by dilute wastewater.
Potential Improvement; Isolate this material from wastewater
streams, pick it up with the vacuum cleaner, and dispose of it into
inedible rendering.
7. Source: Viscera Pans and Treadmill
Problem: Presently excess water is being used to rinse the pans
during production and cleanup.
Potential Improvement: The first step in water reduction is to
install more efficient cleaning nozzles for the pans and treadmill
consistent with government regulations. The second step would be
to install timer-controlled solenoid valves to turn off the water
after production and to allow the cleanup personnel to use only the
amount of water that is necessary for efficient cleaning
procedures.
8. Source: Headwash
Problem: Inefficient use of water.
Potential Improvement: The headwash is not required by the USDA
an3itcan bereHesigned to activate only when a hog is in the
spray area, and the nozzles can be redesigned to reduce total water
usage, as mentioned in the carcass shower.
9. Source: Scraped Fat Area
Problem: Some scraped fat was landing on the floor and being
washed down the drain.
361
-------
Potential Improvement: An additional catch tray has been installed
to minimize this problem.
10. Source: Cleanup Hoses
Problem: Excess water is used for everyday cleanup procedures.
Potential Improvement: Cleanup hoses will be equipped with
squeeze-to-openvalves on the end of the hose and with V-jet
nozzles.
11. Source: Hasher-Washer
Problem: Excess blood and scraps are entering the hasher-washer
drainand ending up being discharged to the grease drains. Also
the contents of the intestines are washed out and flushed down the
drain.
Potential Improvement: The vacuum cleaner technique discussed
previously will reduce scraps and blood entering the system. A
trial will be made to determine the effect on the inedible product
by rendering the intestines without removing their contents.
These improvements require careful consideration of the
consequences of any change. The cooperation of all departments affected
must be enlisted before any construction begins.
RECHARACTERIZATION OF WASTEWATER
Once the desired changes are made the waste streams will be
resampled and analyzed. The recharacterization data can be compared to
the original data to measure the overall reduction in pollution loading.
There are several factors which should be considered in evaluation of
the changes.
An important factor in a comparative study is the statistical basis
of comparison. It is essential that the assumptions of random samples
and representative samples be met. A statistical comparison should
state a level at which a researcher can show statistical confidence that
there actually was a change.
Sometines a process change or a segregation change makes resampling
a particular effluent stream very difficult. A once large volume may be
significantly reduced; the reduced loading may vary more than the
original. The number of samples obtained must be adjusted to compensate
for such a change. The process recharacterization results will be given
in the project final report in a table similar to the original
characterization data (Table 4).
362
-------
ECONOMIC EVALUATION
The cost/benefit analysis of a pollution reduction program for an
industry is a crucial step in the study. The cost of organizing a study
and implementing a proposed change must be weighted against the benefits
of lower water bills, reduced sewer charges, reduced treatment costs,
and increased by-product recovery. The cost/benefit analysis must be
considered for several years into the future. The uncertainty of future
costs for raw water and wastewater treatment makes the analysis very
difficult and requires careful judgement by the industry.
An industry may be considering several changes to reduce pollution
load and conserve water. Each alternative can be evaluated by a
systematic approach as outlined in Figure 3.
The first step for the industry is to realize that a pollution
problem exists, or that a savings can be made by reducing its total
effluent load. This may take the form of a violation of an effluent
constraint or excessive surcharges.
Secondly, the industry must survey the in-house operations to
pinpoint major problem areas and sources for potential improvement. The
most difficult decision facing the industry is selecting the change
which will have the greatest benefit, in the form of pollution
reduction, at the lowest cost.
The third step requires the industry to make a detailed analysis of
the present treatment and disposal costs (Cj). This is the basis for
comparison for the revised costs. In this study the industry operates a
primary and secondary treatment facility and discharges the treated
effluent into a municipal sewage district interceptor. Other industries
may have complete on-site treatment or may discharge the total effluent
to a sanitary district. In all cases the present cost of disposal, the
method used for calculating that cost, and an estimate of future changes
in those costs should be understood.
The fourth step involves studying each proposed modification and
estimating the pollution reduction and water conservation that can be
achieved. The reduced effluent load is used for calculating the revised
treatment cost (Ctr), the cost for installing and operating the
modification (Cm). Also, any benefits (B) due to reduced raw water
volumes and by-product recovery can be calculated.
In step five the cost of the modification is added to the revised
treatment cost and any benefits are subtracted from this total.
363
-------
CO
•i_e.rfi_
AiTC.
*T-
IT
PK.
TKE
.
C 1 1
s.
MT
At.
TC
HI
U
7
'y
i**T ="i
Figure 3. Systems approach to optimizing industrial waste treatment costs.
-------
Ctr + Cm - B
This new cost (Ca) is compared to the original total cost (d); if
C2 is less than Ci, a savings can then be made by installing the
modification. If the new cost is greater than the original cost the
modification can be rejected or reexamined at a different scale. For
example, if a segregation modification is rejected a more complete
segregation alternative can be examined.
In step six the modifications which proved viable are compared and
the ones with the best cost/benefit analysis are chosen if they also
satisfy the company's requirements for space, base of operation,
reliability and other factors. The best judgment of the industry must
be used to select the modifications which will achieve a least-cost,
long-run solution to its pollution problem.
CONCLUSION
The selection of alternative methods for reducing wastewater from
in-plant hog slaughtering operation requires a careful examination of
the process flow diagram, the wastewater collection system, the
characteristics of the wastewater and the existing treatment system.
This information is the basis for comparing new improvements and their
relative effect in treatment performance and costs. In the first phase
of this study the problem areas of the hog slaughtering operation have
been isolated and quantified. More data for the kill shift and the
cleanup shift is now being analyzed.
The next phase of the study will include installing modifications
and recharacterizing the modified effluents to determine the degree of
wastewater reduction achieved. Estimating the effect of these reduced
loads on existing wastewater treatment costs is a difficult task, and
will require careful study of the basic factors which control wastewater
treatment costs. Industries which have complete discharge to a
municipal sewage district may be able to estimate potential savings more
accurately based on existing surcharge rates.
The final report for this project will include several detailed
examples of potential modifications and the economic and operating
feasibility of each.
365
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ACKNOWLEDGEMENTS
This paper presents a preliminary report on progress to date under
EPA Grant R802833-01 to the University of Wisconsin-Madison entitled
"Characterization and Reduction of Specific Wastewaters from In-Plant
Hog Processing Units of the Meat Industry". Oscar Mayer and Company,
Inc., with general offices at Madison, Wisconsin, holds a subcontract on
this project and provides both facility and technical support. Work on
this project has taken place within the hog slaughtering facilities at
the Oscar Mayer and Company plants located at Beardstown, Illinois;
Davenport, Iowa; and Madison, Wisconsin.
In addition to acting as a subcontractor, Oscar Mayer and Company
has provided certain matching funds to support the project.
366
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REFERENCES
1. Cywin, A. and J. D. Denit. Development Document for Effluent
Limitations Guidelines and New Yource Performance Standards for the
Red Meat Processing Segment of the Meat Product and Rendering
Processing Point Source Category. US Environmental Protection
Agency, Washington, DC. EPA-440/l-74-012a. February 1974.
2. American Meat Institute. Meat Facts. 1974 edition. July 1974.
3. American Meat Institute. Weekly Report. 18/8). February 7, 1975.
4. American Meat Institute. Private Correspondence. 1974.
367
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EGG PROCESSING WASTE RECOVERY
N. Ross Bui ley*
INTRODUCTION
Most food processing operations generate a waste effluent which
contains diluted edible material. Operations such as conveying, mixing,
peeling, cutting, cooking, sterilizing and packaging all convert some
useable food material into a form which in many cases is considered
unfit for human consumption. The product may be considered a waste
because of palatability, microbiological, or economic reasons.
Even with all the rhetoric about preserving the environment, the
waste handling method chosen by most processors will be the one which is
cheapest and will still meet the pollution control standards set for his
operation. The egg processing industry will be no different in this
respect from any other industry. The first consideration for any waste
treatment system should be to minimize waste production and water use
and to maximize water reuse through partial purification and recycling.
The next consideration should be for potential product recovery from
waste streams followed by final treatment and disposal.
Our first studies on the handling of egg processing wastewater were
centered on an aerobic treatment method using an extended aeration
system.*
While carrying out this research in our laboratory, it was felt
that since a large fraction of the solids in the wastewater was pure egg
albumen and yolk, a chemical precipitation or some other form of
treatment should remove a large portion of this high protein waste.
This could significantly reduce the size of any subsequent waste
treatment system which might be required and should produce a saleable
product. The other main sources of waste from this food processing
system are the egg shells with the albumen which adheres to the shells
*Associate Professor, Department of Agricultural Engineering, University
of British Columbia, Vancouver, B.C., Canada, V6T 1W5.
368
-------
during the breaking operation. This waste if dried should produce a
potentially saleable product as a feed additive for poultry.
The purposes of this research were (1) to investigate the
feasibility of pretreating the processing wastewater for removal of the
egg solids, and (2) to study the problems and potential returns from
drying of the egg shells with their associated albumen.
EGG PROCESSING: WASTEWATER SOLIDS RECOVERY
Characteristics
The characteristics of the wastewater generated from the breaking
and processing operations vary from plant to plant but typical
characteristics are shown in Table 1.
These waters will vary considerably throughout the day depending on
methods of water reuse, detergents used in egg cleaning and any waste
slug loads released during or at the end of a processing operation. The
colloidal nature of the egg wastewater makes solids removal by
clarification almost impossible.
Solids Recovery Systems
Chemical Coagulation—Aluminum ions are used in many physical-chemical
treatment systems to aid in solids removal. Laboratory tests were
conducted on the processing wastewater to determine the effect of pH and
alum concentration on egg solids coagulation. If the wastewater was
left untreated for 24 hours there was very little coagulation and no
noticeable settling. The addition of aluminum sulfate accompanied by a
pH adjustment did produce a settleable floe. Typical results are shown
in Table 2. The pH of the original waste varied from 10 to 11.5 and was
adjusted to pH 5.1 for maximum floe formation using 3N HaSO<*. Solids
coagulation and settling varied to some extent for different
concentrations of alum but the removal was always greater than 50
percent for alum concentrations above 200 parts per million. Below 200
parts per million, the solids removal efficiency dropped significantly.
The percentage of solids which coagulated and settled increased with
decreasing solids concentration (Table 3). The very high solids removal
efficiencies for solids concentration less than 1,000 parts per million
indicated that a second addition of alum to the supernatant might
increase solids removal.
369
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Table 1. TYPICAL EGG GRADING AND PROCESS
WASTEWATER CHARACTERISTICS
Analysis
BOD5
COD
Total solids
Kjeldahl-N
Nht-N
NO^-N
PO,E-P
mg/1
6,300
9,780
6,950
537
48
2
144
Table 2. EFFECT OF ALUM CONCENTRATION ON EGG SOLIDS REMOVED
Al2(SOi,)3, ppm
600
400
200
100
50
Total egg solids, ppm
Wastewater
4,130
4,130
4,130
4,130
4,130
Supernatant
la
1,339
2,107
1,855
2,744
3,074
2b
1,179
1,767
1,552
2,508
2,917
% Solids
removed
1
68
49
55
33
26
2
71
57
62
39
30
aFresh waste.
Five-day old waste.
370
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Table 3. EFFECT OF EGG SOLIDS CONCENTRATION ON SOLIDS REMOVAL
EFFICIENCY A12(S003 ADDITION TO GIVE 200 PPM IN WASTEWATER
Total solids
wastewater
ppm
6,147
4,265
3,073
2,132
1,537
1,066
1,024
768
711
533
Total solids
in
supernatant,
ppm
3,836
2,288
1,116
876
816
368
236
152
68
40
% Removal
37.6
46.4
63.7
58.9
-46.9
65.5
77.0
80.0
90.0
92.0
BOD 5, ppm
Before
clarifi-
cation
3,535
1,240
640
552
470
After
clarifi-
cation
720^
390
75
60
57
% Removal
79.6
68.6
88.0
89.1
88.0
371
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The addition of a second 200 parts per million alum to the
supernatant from the first clarification (2,288 parts per million egg
solids remaining) resulted in the formation of a second floe which
removed an additional 15 percent of the egg solids. This indicated that
most of the remaining solids were in a form which could not be readily
removed by flocculation. The BOD5 removal accompanying the flocculation
and_solids removal varied from 70 to 90 percent. Over 95 percent of the
SO^' remains in solution and does not become associated with the floe.
Greater than 90 percent of the added aluminum is removed in the floe.
The floe when dried contained about 10,000 parts per million aluminum on
a dry weight basis. Feeding trials should be conducted on the waste
material to determine its acceptability as a feed additive. Previous
feeding trials using a fish processing waste with aluminum
concentrations in this order did not present any feeding problems when
the waste represented up to 5 percent of the total ration.
Electrocoagulation
Because of the proteinaceous characteristics of the waste materials
in the wastewater, it was felt that the colloidal nature of the waste
might lend itself to treatment by electrocoagulation. A laboratory
batch treatment system was studied. Two aluminum electrodes (abour 20
square centimeters surface area each) were placed in 100 milliliters of
waste in beakers and a 20 volt D.C. potential applied. The effects of
time, temperature, electrode surface area, electrode separation, pH and
waste concentration on floe formation and settling were studied.
A floe forms on the anode immediately with a gas being released
from the cathode. The floe had a tendency to adhere to the electrode
with a resulting decrease in current. Tapping the electrodes gently
released the floe and it floated to the surface forming a whitish froth.
The current varied from 100 to 400 milliamperes (ma) with the irregular
release of the floe but averaged about 250 ma.
The solids removal efficiency was found to have a non-linear
response with time as shown in Table 4. The reproducibility after 10
minutes was found to be very poor and varied from 30 to 50 percent
removal. This is most probably attributable to the very simple
apparatus being used which was not able to keep the distance between the
electrodes perfectly constant and was unable to remove the floe'from the
surface of the anode in a reproducible manner.
The experiments did show that a very high proportion of the
effluent solids (60 to 70 percent) could be removed as a floe within 15
minutes. The concentration of the solids in the floe, if skimmed from
the surface, was 2.3 percent total solids. This concentration increased
372
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Table 4. EGG PROCESSING WASTEWATER SOLIDS REMOVAL
DURING ELECTROCOAGULATION
Time, minutes
0
5
10
15
20
25
30
45
Total solids in
solution, mg/1
4,450
3,630
3,140
1,604
1,150
850
815
560
Solids removal
as floe, %
0
18
30-50
64
74
81
82
87
373
-------
to about 3 percent solids if the batch electrocoagulation continued for
25 minutes. This solids concentration might be increased due to
compaction of this floe during a commercial electrocoagulation process
as has been found for other food wastes.3
All of the floe was observed to form on or near the anode. A clear
region could be seen extending from the cathode during the treatment.
The pH in this region was found to be very high (pH greater than 12) and
was probably the result of the build-up of OH" around the cathode as
hydrogen ions were being neutralized and released as hydrogen gas.
There was a relatively high average rate of attrition for the anode (1
milligram per minute). Using carbon electrodes also resulted in the
formation of a floe on the cathode indicating that aluminum ions were
not necessary for floe formation. But, the floe formed faster, required
less power and seemed more stable when the aluminum cathode was used
indicating an interaction of the aluminum ion with the floe. Further
studies on the choice of electrode material and ion interaction are
required before a pilot scale testing of the system should be attempted.
Varying the pH of the wastewater at the start of the experiment
from 4.0 to 9.5 had no significant effect on the floe formation and
solids removal after 10 minutes. Increasing the wastewater temperature
from 20 degrees C to 49 degrees C increased the floe formation and
solids removal in the first 5 minutes of electrocoagulation from about
18 to 35 percent solids removal but this advantage was lost within 15
minutes after which time there was a slight reduction in solids removal
at the higher temperature. Since normal coagulation of albumen begins
around 60 degrees C, it appears that additional heating of the
wastewater to enhance the electrocoagulation process is unwarranted.
Higher temperatures closer to the natural coagulation temperature could
give very different results.
Optimum electrode materials and surface area spacing, arrangement
and voltage, all should be investigated before the practical use of the
electrocoagulation process can be determined for egg processing
wastewater.
Based on our results, electrocoagulation is able to remove a high
percentage of the egg solids producing a very stable and easily managed
floe. Further studies should be carried out in this area.
EGG PROCESSING: SHELL DRYING
Samples of egg shells were collected from a commercial egg breaking
machine. The shells were allowed to drain and then dried in a tray
374
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drier ( - 140 degrees F) and weighed at intervals to obtain a drying
curve (Figure 1). Samples of these dried shells were then further dried
in a 105 degree C oven to obtain their bone dry weight. These shells
were then boiled in 0.625 M NaOH to remove any adhereing albumen,
cuticle, and membrane. The shells were then filtered, dried and weighed
to find the amount of protein associated with the shell.
The materials balance on the waste stream from the egg breakers is
shown in Figure 2. The stream includes the shells, adhering albumen,
and the albumen removed from the individual egg inspection trays by a
fine spray wash. The waste stream does not include any of the rejected
eggs. The balance shows that even though the shells are allowed to
drain, the bulk of the protein still sticks to the surface of the shell.
This shell-albumen mix is very messy to handle and to dry but as the
moisture content drops below 15 percent, the membranes become brittle
and break up leaving a material that has a relatively heavy shell
fraction and a light powdery membrane fraction. This light fraction
will require some form of dust collection system to avoid protein loss
and to prevent air pollution during the drying operation.
Feed trials should be conducted to determine the acceptability of
the dry shell-albumen mix as a feed ingredient for poultry. Waste
recovery systems are on the market for removing some of the free albumen
from the shells in the wet state, but some problems have been
experienced with their operation. The finely ground egg shell which
results from these separators is considered undesirable as a poultry
feed by some growers.
For a processing plant handling 600 cases of eggs per day (30 dozen
eggs per case) the shell with its associated albumen after drying
amounts to about 3,000 pounds of product. This is excluding the albumen
when it is removed during draining and includes 450 pounds of egg solids
which are about 70 percent protein.
The economics of drying the shell-albumen fraction have not been
included in this paper due to the variety of drying systems possible and
the very rapid changes in the cost of energy. But, based on the cost of
energy for drying at $1.00 per 1,000 cubic feet of natural gas and using
2,000 BTU's per pound of water removed, the cost of energy for removing
the water from the shell-albumen stream would amount to about U per
pound of dry product. This appears to be low enough to encourage
further study in this area.
375
-------
100
30
60 90
TIME ( MlN .)
120
Figure 1. Water loss from albumen-shell mix
in forced air drier (140°F).
376
-------
CO
-a
-a
BREAKER DISCHARGE
100 g (-x- 10 eggs)
I
1
SHELL AND ADHERING
ALBUMEN
85.6 g
24. 5* | 75.53!
I 1
WATER SHELL AND DRIED
(21.0 g) ALBUMEN
64.6 g
1 '
DRIED ALBUMEN SHELL
AND MEMBRANES 54.9 g
9.7 g
1
1
Ca P
20.14 g 0.13 g
1
FREE ALBUMEN
14.4 g
1
1 1
WATER ALBUMEN
(12.6 g) (1.8 g)
TOTAL EGG SOLIDS - 11.5 g
TOTAI WATFR - 33.fi g
Mg
0.21 g
Figure 2. Profile of egg breaker waste discharge for about ten eggs.
-------
CONCLUSIONS
Methods are available for removing or reducing the waste content of
effluent streams from egg processing plants.
The addition of 200 parts per million alum to egg processing waste-
waters at pH 5.1 produces a settleable floe. The egg solids removal
efficiency resulting from the settling of this floe is a function of
initial solids concentration and is in order of 50 percent for a typical
egg processing wastewater. The BODs removal efficiency is less
dependent on initial BODs concentration and is in the order of 70
percent or greater. Electrocoagulation of the wastewater produces a
stable floating floe and can remove a large percentage of the total egg
solids in a relatively short time.
Drying of the broken egg shells with their associated albumen would
appear to represent a viable alternative for handling this particular
waste stream.
ACKNOWLEDGEMENTS
The author wishes to acknowledge the partial funding of the project
by the British Columbia Department of Agriculture and the technical
assistance of Miss Judy Schweb.
378
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REFERENCES
1. Bulley, N. R., L. M. Staley, and P. W. Soper. Biological Treatment
of Egg Processing Wastewater. Proceedings of the 1973 Cornell
Agricultural Waste Management Conference. 1973. p. 306-315.
2. Claggett, F. 6. Clarification of Fish Processing Plant Effluents
by Chemical Treatment of Air Flotation. Fisheries Research Board
of Canada. Technical Report No. 343. 1972.
3. Beck, E. C., A. P. Giannini, and E. R. Ramirez. Electrocoagulation
Clarifies Food Wastewater. Food Technology. 28:18-22. 1974.
379
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ROTATING BIOLOGICAL SURFACE TREATMENT OF
VEGETABLE CANNING PROCESS WASTEWATER
Robert F. Roskopf*
Francis D. Osborn*
Dale A. Watson*
G. E. Flann**
INTRODUCTION
A one-season pilot plant study was initiated on March 21, 1974, by
the Environmental Pollution Control (EPCO) Division of the George A.
Hormel Company of Austin, Minnesota. The study was designed to
determine the effectiveness of the rotating biological surface (RBS)
process when used for the treatment of vegetable canning process
wastewater.
All phases of the study were conducted in Owatonna, Minnesota, on
process wastewater discharged by the Owatonna Canning Company. The
facility in Owatonna, which is located approximately 70 miles south of
Minneapolis, cans asparagus, peas, beans, corn, and pumpkin on a
seasonal basis and cans beef stew year-round.
Three RBS pilot plants identified as "polyplant-1", "polyplant-2",
and "lagplant" were used during the study. Polyplants received screened
process wastewater. Effluent from a three-acre, 10 million gallon
anaerobic lagoon, which is the first stage of the Owatonna Canning
Company wastewater treatment system in Owatonna, was treated with the
lagplant (see Figure 1). Polyplant-2 and the lagplant were not
available until August of 1974, but polyplant-1 was used throughout the
study.
*Sanitary Engineer, Director of Plant Operations and Research, and
Sanitary Engineer, respectively, Rieke Carroll Muller Associates, Inc.,
Hopkins, Minnesota.
**Technical Services Representative, Environmental Pollution Control
Division of George A. Hormel Company, Austin, Minnesota.
380
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OWATONNA CANNING COMPANY-
PROCESS WASTEWATER
03
OO
SOLIDS TRUCKED
TO HOG FARM
THIRD-STAGE LAGOON
AREA=I.5ACRES±
IBRATING
SCREENS
ANAEROBIC LAGOON
ASEA =3ACRES±
VOLUME=
TO POLYPLANTS
TO LAGPLANT
SECONO-STAGE
LAGOON
AREA =12 ACf'f:34
FROM
^OLYPLANTS
SECOND-STAGE LAGOON
AREA = 2O
Figure 1. Schematic of water pollution control facilities at Owatonna Canning Company,
Owatonna, Minnesota.
-------
The EPCO Division of the George A. Hormel Company retained the
consulting engineering firm of Rieke Carroll Muller Associates, Inc., to
reduce all data generated during the study, and to prepare final reports
on the study. Pilot plant study results were presented in two reports.
The first, or Phase I report, which was completed on November 22, 1974,
evaluated data acquired from polyplant-1 for the period of April 5, 1974
to June 27, 1974. During this time beef stew and asparagus were being
canned at the Owatonna Canning Company. The second (Phase II) report,
evaluated data acquired from all three pilot plants for the period
August 11, 1974 to November 13, 1974. Various combinations of corn,
green beans, pumpkin, and beef stew were being canned during the second
phase of the study.
Facilities Description
Each RBS unit was housed in a prefabricated metal shed with an
inside covering of urethane foam insulation. Each utilized a semi-
cylindrical tank 4.23 feet long and 4.0 feet in diameter for a flow-
through chamber. The tank was divided into four equal-volume
compartments by means of 1/4-inch partitions. Eight 47-inch diameter
rotating discs per compartment were mounted on a center drive shaft so
that approximately 29 percent of the disc surface area was submerged in
the tank contents. A pilot unit contained a total of 771 square feet of
surface area, with approximately 193 square feet in each of the four
stages.
Connections between the compartments or stages permitted four-stage
series operation with flow parallel to the flat sides of the rotating
discs. These connections were made by means of external pipes which by-
passed the compartment partitions on the outside of the tank. Samples
of the effluent from each compartment were withdrawn by tubing pumps
(multichannel peristaltic cassette pumps) connected to these pipes by
means of plastic tubing. Figure 2 is a schematic diagram of a typical
pilot plant unit.
It was necessary to pump wastewater to each of the pilot RBS units.
To solve problems that were primarily caused by floatable solids present
in the wastewater, a two-compartmented (in series) primary clarifier was
installed ahead of the two polyplants prior to Phase II of the study. A
centrifugal pump took suction from the Owatonna Canning Company process
wastewater wetwell and discharged into the first compartment of the
clarifier. Wastewater pumpage exceeded the requirements of the two
pilot plants; the excess overflowed the clarifier and returned to the
wetwell. The rotary gear pumps that fed polyplant-1 and polyplant-2
took suction from near the bottom of the second clarifier compartment.
The capacity of each clarifier compartment was 183 gallons.
381
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3'-l09/IG'
EIGHT(e)47"DIAr
POLYSTYRENE DISC
EACH STAGE.
CHAINGUARD
^.OPPOSITE: SIDE
\ OF TANK
-10 3/4"
Figure 2. RBS pilot unit utilized during the RBS study at Owatonna
Canning Company.
383
-------
Since the lagplant received lagoon effluent which was devoid of
large particles, no clogging problems were experienced with this pilot
unit. Anaerobic lagoon effluent was pumped to the first stage of the
lagplant by means of a rotary gear pump. Lagplant flow was maintained
at 0.2 gallons per minute from August 11, 1974 to September 16, 1974 and
at 0.5 gallons per minute from September 17, 1975 to October 11, 1974 at
which time the lagplant was shut down.
Throughout the entire study period flows were checked on the pilot
plants two to three times each sample period by means of a one-liter
graduated cylinder and a stop-watch. In addition, Stevens level
recorders were used in conjunction with weirs on the effluents from all
pilot units to continuously record flow rates throughout the entire 24-
hour sample period.
Wastewater Types
Various types of pilot unit influent were encountered during the
study. Initial study results were obtained during the canning of beef
stew and asparagus. A combination of beef stew and corn canning process
wastewater was treated from August 11 to August 19, 1974. To this
combination was added green bean canning wastes on August 19, and the
three were processed together until September 9, 1974. Beef stew
canning was temporarily discontinued on Septmber 9, 1974. Corn and
green beans were processed from September 9, 1974 until September 21
when the corn and green bean packs ended. Beef stew canning resumed,
and on September 24 the pumpkin pack began. Pumpkins were"canned until
October 4, 1974 after which time only beef stew was canned through the
termination data of the pilot study.
PROCEDURES
Operation
Preliminary plans were to sequentially operate the pilot plant
units as 4.0, 5.0 and 6.0 revolutions per minute to determine plant
performance-revolutions per minute relationships, but the development of
oxygen limiting and perhaps septic conditions while operating polyplant-
1 at 4.0 revolutions per minute in the Phase I portion of the study
necessitated an early increase in speed of disc rotation. It was found
that operation at 8 revolutions per minute would maintain adequate
dissolved oxygen under all conditions. Polyplant-1 was changed from 4
to 8 revolutions per minute on April 13, 1974, and all units were
384
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operated at 8 revolutions per minute for the remainder of the study
period.
It is noted that the velocity of a point on the outer edge of a 4-
foot diameter disc is equal to the velocity of a point on the outer edge
of a full-scale 11-foot diameter disc when the rate of rotation of the
small disc is 2.75 times the rate of rotation of the large disc. This
relationship makes it necessary to operate small disc pilot units at a
relatively high revolution per minute to simulate shear and turbulence
conditions encountered in full size units operating at a lower
revolution per minute. Since full scale RBS units often operate in the
range of 2 to 3 revolutions per minute, it was not unrealistic to
operate the pilot units at 8 revolutions per minute.
From August 11, 1974 to September 16, 1974 the flow rates were
maintained with minimal fluctuations at 0.2 gallons per minute to
polyplant-1 and at 2.0 gallons per minute to polyplant-2. On September
17, 1974 the flows were changed to 0.5 gallons per minute for polyplant-
1 and 1.0 gallons per minute for polyplant-2. These flows were
maintained (except for times when pumpkin wastes caused clogging
problems) until November 13, 1974 at which time the project was
terminated.
Sampling and Analyses
Three 24-hour composite samples were collected each week from five
sampling points per pilot unit, which included the pilot plant influent
and the effluent from each of the four stages of all units. Samples
were collected with multichannel peristaltic cassette tubing pumps
through plastic tubes connected to the sample points. Samples were
discharged to one-gallon plastic containers packed in ice. The low-rate
sampling pumps worked continuously to collect approximately one gallon
of sample per sampling point during each 24-hour period. The positive
displacement characteristics of the tubing pumps permitted operation
that was relatively trouble free. Upon completion of each sampling
period, the samples were promptly delivered to the laboratory for
analyses. An independent laboratory, Minnesota Valley Testing
Laboratories, Inc., of New Ulm, Minnesota, was retained to collect all
samples, maintain sampling equipment, and handle all necessary field
work.
Temperature and dissolved oxygen (DO) levels were determined on
pilot unit influents and in each stage about mid-morning the day before
each sample run and again during the day of sampling. Dissolved oxygen
determinations were made in the field with a Yellow Springs Inst. Co.
analyzer.
385
-------
On sampling days a detailed verbal description of the growth on
each of the four stages of each pilot unit was recorded by the
independent laboratory service field man.
All routine laboratory analyses were performed by an independent
testing laboratory; Minnesota Valley Testing Laboratory, Inc., of New
Ulm, Minnesota during Phase I of the project. Beginning August 11, 1974
all such analyses were performed in the George A. Hormel Company
laboratory at Austin, Minnesota by Hormel personnel.
Since intermediate or final sedimentation basins were not used in
the pilot plant study, it was necessary for efficiency determinations to
simulate a clarification system by settling samples in the laboratory
prior to analyses. Whole influent samples and laboratory settled
effluent samples from all stages were analyzed. Supernatant was
withdrawn from Imhoff cones after one hour of settling for analyses on
all stage effluent samples.
All laboratory determinations were performed in accordance with
Standard Methods for the Examination of Water and Wastewater, thirteenth
edition.Routine laboratory work included BOD, COD, Kjeldahl, ammonia,
and nitrate nitrogen; phosphorus; and solids analyses.
RESULTS
Polypi ant performance evaluations were based upon 25 24-hour
composite samples collected during Phase I of the study, and 57 24-hour
composite samples collected during Phase II. Lagplant performance was
monitored by collecting and analyzing 21 24-hour composite samples.
Biomass Description
Trends in biogrowth included changes in growth thickness, evenness,
texture, and coloration. Variations in biogrowth from stage to stage
were normally apparent. Typically, all stages started out with a light
brown, fairly even coloration. Thickness and evenness progressed
through the stages with time. Evenness was more apparent on stages one
and two. Once the growth was established, the thickness of the
biogrowth increased rapidly on stages one and two and progressively more
slowly through stages three and four. As the thickness increased, the
biogrowth became darker in color and fibrous in texture. Growth in
stages three and four was frequently nodular in character under low
loading conditions. This was especially apparent in the lagplant
throughout the entire study. The lagplant discs seldom showed complete
386
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coverage In stages three and four. Under heavy loading conditions the
biogrowth in the polyplants frequently had smooth, even characteristics
in all stages.
Although slight variations were noted in the polyplants with each
waste type, colors typically varied over a two- to three-week period
from light brown to dark brown to blue-gray to almost black. The
darkest color was normally representative of the thickest or heaviest
biogrowth. During corn canning the biogrowth colors were typically
milky brown. Orange predominated during the pumpkin season. The
biogrowth coloration associated with the lagplant did not change with
waste types and was generally darker than polyplant color.
Although some degree of sloughing undoubtedly occurred
continuously, the rate increased as the biogrowth became heavier and
darker. In the dark growth stages, sloughing became very heavy with the
majority of biomass frequently being lost over a two- to four-day
period. This phenomenon may be analogous to the "unloading" frequently
observed in trickling filters. Normally, isolated patches of heavy
biogrowth remained upon the disc surface after unloading was complete.
The bare areas among the patches of biogrowth often required one to two
weeks under light loading conditions to become covered again with the
light brown substance that typified initial stages of biogrowth.
Following heavy loading conditions regrowth was fast with dramatic
increases in biogrowth frequently occurring in 24 to 48 hours.
The third stage normally appeared to carry a greater biomass
inventory than the fourth stage. However, the complete, uniform
coverages of the discs by heavy biomass characteristics of stages one
and two was seldom observed in stages three and four under light load
conditions.
In stages three and four, a light brown coloration was frequently
observed among patches of bluish-gray biogrowth. Sloughing apparently
occurred at a rate which permitted only isolated patches of mature
biogrowth to develop.
Stages one and two in all units often alternately unloaded their
biomass inventories. Thus, when the discs of one stage were observed to
contain heavy biogrowth coverage, the other stage frequently exhibited a
sparse, patchy growth associated with unloading.
Early in the Phase I study with the discs turning at 4 revolutions
per minute, low dissolved oxygen conditions developed concurrently with
the development of heavy biogrowth. At this time, the biomass in all
stages became very black, and unloading occurred. After the increase of
disc speed to 8 revolutions per minute, dissolved oxygen was maintained
387
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in all stages and a recurrence of the dark black growth was not
observed.
Polypi ants
Flow rates to the polyplants were intentionally varied from about
0.4 gallons per day per square foot to 3.7 gallons per day per square
foot. However, a variety of wastewater types and many uncontrollable
variables were encountered during the study.
Temperature—Raw wastewater temperatures varied from 8 degrees C to 28
degreesC7 and averaged about 22 degrees C. RBS treatment generally
lowered the wastewater temperature one or two degrees C, although
temperature drops of as much as 8 degrees C were observed.
Dissolved Oxygen—Dissolved oxygen (DO) levels in the influent waste-
water varied from 0.4 to 5.4 milligrams per liter. At the lower flow
rates effluent DO levels were usually 4 to 7 milligrams per liter higher
than the influent levels, and at the higher flow rates the effluent DO
levels were about 0.5 to 2.0 milligrams per liter higher than the
influent levels. In polyplant-2, which was operated under the higher
hydraulic loads, the DO levels frequently dropped in going from the
second to the third stage and occasionally in going from the first to
the second stage. In no case, however, did the DO drop below 0.6
milligrams per liter.
J3H---A recording pH meter monitoring the influent to the polyplants
revealed wide fluctuations in raw wastewater pH. The lowest pH recorded
was 2.5 and the highest was 10.2. Daily variations usually ranged from
about 4.0 to 9.0. Throughout most of the 24-hour sampling period the pH
was in the range of 4 to 6. The high pH values were experienced over a
two to three hour period commencing in the early morning hours -
probably the result of wash-down operations following the completion of
the second shift of processing.
Biochemical Oxygen Demand—The BOD5 of the screened Owatonna Canning
Company process wastewater ranged from 240 to 1,800 milligrams per
liter. After treatment with the four-stage RBS system the effluent BOD5
varied from 6 to 1,385 milligrams per liter. The large spread in the
BOD values represents the variability typically encountered in the food
processing industry as the result of product changes and daily water
usage fluctuations.
In several of the observations the BOD5 removal efficiency dropped
in going from two stages of treatment to three stages of treatment.
This trend was most noticeable in polyplant-2 which was operated at very
388
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high flow rates, and it was usually accompanied by a decrease in DO
concentrations. This also occurred in other stages, but to a lesser
extent.
Average BOD5 concentrations and BOD5 removal efficiencies have been
calculated based on waste type and flow rate and are presented in Table
1. This analysis is rather general but does serve to point out some
trends. The most obvious trend is that of higher BOD5 removal
efficiencies for the lower flow rates for any given waste type. Also
noticeable is the dependence of BOD5 removal on waste type. For
example, when comparing the BOD5 removal efficiencies at a flow rate of
288 gallons per day for the different wast types, the highest
efficiencies were obtained when treating the corn-green bean wastewater
with lower efficiencies for the beef stew-corn-green bean waste and the
beef stew-corn waste. At the higher rates of flow these trends became
less apparent because of the decreasing consistency of performance.
Since beef stew-corn wastewater was treated first, followed by a
combination beef stew-corn-green bean wastewater and then corn-green
bean wastewater, the higher removal efficiencies for the corn-green bean
wastewater may have resulted from biomass acclimation to the high-
strength corn wastewater.
Figures 3 through 6 present the relationships between BOD5 removal
efficiency and organic loading expressed in terms of pounds of BOD5
applied per day per 1,000 square feet for one, two, three, and four
stages of treatment during Phase II of the study. The relationships
have been approximated by fitting regression lines to the data with no
distinction being made for waste type. However, in Figures 3 through 6
the different waste types have been indicated through the use of various
symbols. It should be noted that the data were obtained from two pilot
units operating in parallel and that most of the data at the low
loadings came from one unit while the data for the higher loadings came
from the other unit. Although the changes in performance could be due
to some unknown difference between units, it was assumed that the two
units would perform similarly under identical conditions and that the
differences in performance were related to loading rates, either
hydraulic and/or organic.
Figures 7 through 10 present the results of BOD5 removal efficiency
as a function of hydraulic loading expressed as gallons per day per
square foot for one, two, three and four stages during Phase II of the
study. The surface area considered in calculating the hydraulic loading
is taken as the total surface area of the number of stages being
evaluated for a given graph. Thus, for any given flow rate, as the
number of stages increases, the hydraulic loading decreases.
389
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Table 1. BOD DATA AVERAGES FOR POLYPLANTS WITH RESPECT TO WASTE TYPE AND FLOW
Waste type
Flow to plant(gal/day)
No. of observations
Polyplant no.
Average BOD (mg/1)
Influent
First-stage effluent
Second-stage effluent
Third-stage effluent
Fourth-stage effluent
Average of percent BOD
removal observations
One-stage
Two-stages
Three- stages
Four- stages
PHASE I
B
366
12
1
992
486
321
275
192
51.0
67.6
72.3
80.6
B.A
381
13
1
534
198
116
74
43
62.9
78.3
86.1
91.9
PHASE II
B,C
288
3
1
957
785
690
552
392
23.0
34.9
46.1
63.8
B,C
2880
3
2
1187
992
808
998
760
20.2
37.6
17.6
44.3
B,C,GB
288
6
1
852
593
426
199
154
29.9
52.5
76.0
80.9
B,C,GB
2880
6
2
1225
1263
1092
1038
1036
-4.9
10.4
13.8
14.5
C,GB
288
4
1
1146
691
321
114
71
39.4
72.1
90.2
93.8
C,GB
715
2
1
1128
705
582
548
375
37.7
48.1
51.0
66.8
C,GB
1400
2
2
1112
940
852
798
708
14.7
21.8
27.4
35.3
C,GB
2880
4
2
1109
1002
935
912
862
9.5
15.0
17.2
21.8
B
680
12
1
735
477
448
265
174
33.7
43.0
64.6
77.2
B
1420
12
2
715
562
474
423
378
20.7
33.8
41.1
47.7
OS
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NOTE: A = asparagus,
B = beef stew, C = corn, GB = green beans, P = pumpkin
-------
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Q BEEF STEW, CORN, GREEN BEANS
O CORN,GREEN BEANS
Q 8E6F STEW, PUMPKIN
I 8EEF STEW, CORN
80 IOO 120 140
BOO APPLIED, Ib/day/iooo iq ft
Figure 3. One-stage organic load - BOD removal observations for polyplants during
RBS treatment of canning process wastewater at Owatonna Canning Company.
220
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O BEEF STEW, PUMPKIN
« BEEF STEW, CORN
10
20
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BOO APPLIED, !b/day/icoo »q ft
80
90
100
110
Figure 4. Two-stage organic load - BOD removal observations for polyplants during
RBS treatment of canning process wastewater at Owatonna Canning Company.
-------
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BOD APPLIED, Ib/day/looa sq fr
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Figure 5. Three-stage organic load - BOD removal observations for polyplants during
RBS treatment of canning process wastewater at Owatonna Canning Company.
-------
co
co
100
80
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30
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BOD APPLIED, Ib/day/1000 sq ft
80
SO
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Figure 6. Four-stage organic load - BOD removal observations for polypiants during
RBS treatment of canning process wastewater at Owatonna Canning Company.
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O CORN, GREEN BEANS : ;
O BEEF STEW, PUMPKIN
x BEEF STEW, CORN
8 !O 12 14
HYDRAULIC LOADING, «al / day / sq ft
18
20
Figure 7. One-stage hydraulic load - BOD removal observations for polypi ants during RBS
treatment of canning process wastewater at Owatonna Canning Company.
-------
100-
80
60
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40-
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IU
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o
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HYDRAULIC LOADING , gal / day / tq ft
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a BEEF STEW, CORN, GREEN BEANS
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8 10 12 14
HYDRAULIC LOADING, gal / day / tq ft
16
18
20
22
Figure 10. Four-stage hydraulic load - BOD removal observations for polyplants during RBS
treatment of canning process wastewater at Owatonna Canning Company.
-------
The Phase II study differed from Phase I in that the flow rate was
purposely varied in Phase II in order to assess the effect of flow rate
on performance. Unfortunately, an in-depth analysis of performance
versus hydraulic loading was not possible since the type of waste
changes frequently throughout the study. However, Figures 7 through 10
illustrate the definite existence of a trend toward increasing BOD5
removal efficiencies at lower hydraulic loadings for all numbers of
stages of treatment and greater consistency of performance with
increasing stages of treatment.
For most of the waste streams the data available are for a low flow
rate and a very high flow rate. However, data for the corn-green bean
wastewater are available for four different flow rates. This specific
data lends itself well to an analysis of BOD5 removal efficiency versus
flow rate (or hydraulic loading). Figure 11 presents the relationship
between average BOD5 removals versus flow rate applied to the pilot unit
with a family of curves accounting for different numbers of stages of
treatment. The data plotted in Figure 11 were excerpted from Table 1
and the curves shown are simple "visual best-fit" approximations.
The curves in Figure 11 indicate several things: (1) BOD5 removal
performance was very much a function of flow rate, with best removals
realized at lower flows, (2) increasing the number of stages of
treatment (thus reducing hydraulic loading) improved the BOD5 removal at
all flow rates, and (3) the effect on percent removal of providing
additional surface area was largest at low to medium flow rates.
In Figure 12 the average BODs removal performance during Phase II
of the study is plotted as a function of hydraulic loading in terms of
gallons per day per square foot for all waste streams taken composite!y.
In addition, as an indication of data spread, one standard deviation has
been plotted on each side of the mean value for each set of data. (With
a normal distribution of the data, approximately 68 percent of the data
points would fall within one standard deviation on either side of the
mean.)
Biological treatment processes are usually considered to exhibit
kinetics typical of first or higher order reactions with respect to
carbonaceous BOD removal. It is known that for reactions of first order
or higher, better performance is obtained when the flow regime through
the reactor is plug-flow rather than completely-mixed, all other
conditions being equal. One method of approximating plug-flow
conditions is to have a series or staged reactor consisting of several
completely-mixed compartments, with plug-flow conditions being more
closely approximated by increasing the number of stages.
399
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CORN-GREEN BEAN WASTE
4 STAGES
3 STAGES
2 STAGES
STAGE
400 BOO 1200 1600 20OO 2400 -28OO
FLOW TO PILOT UNIT, gal/day
Fiaure 11 Flow - BOD removal observation averages for polyplants during RBS treatment
' of corn-green bean process wastewater at Owatonna Canning Company.
-------
80
60-
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ta
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O 4 STAGES
B 3 STAGES
t> 2 STAGES
O I STAGE
ONE STANDARD DEVIATION
6x AVERAGE BOD REMOVAL,
{ NOTE : ALL WASTE )
8 10 12 14
HYDRAULIC LOADING, gal / day / sq ft
16
18
20
Figure 12. Composite of hydraulic load - BOD removal observation averages for polyplants
during RBS treatment of canning process wastewater at Owatonna Canning Company.
-------
Therefore, considering the "staged" design of the RBS pilot units
used in this study, one would expect to obtain better BOD removals as
the number of stages of treatment increases, all other conditions being
equal. The data for a given flow rate cannot be compared since the
results obtained when using more stages of treatment acutally reflect
the improved performance due to increasing the surface area and
decreasing the surface loading. It becomes necessary then to make the
analysis for similar total hydraulic surface loading rates (with the
assumption that equal hydraulic surface loading rates result in equal
contact times between substrate and biomass).
The effect of staging can be examined by referring to Figure 12.
For example, considering the third and fourth points left of the
ordinate, it is seen that the fourth data point representing four stages
of treatment indicates better BOD5 removal than the third data point
which represents two stages of treatment even though the hydraulic
loading in the four-stage case is slightly higher. This type of
relationship existed for several other points, and was perhaps the
result of staging. However, the fact that the type of wastewater being
treated was not constant complicates this argument. For the points
falling near 3.6 gallons per day per square foot, for example, better
performance was obtained from fewer stages of treatment - completely
contradicting logical expectations. Here again, however, waste type may
have been the dominating factor. At any rate, it should be stated that
although these pilot study results do not prove the benefits of staging,
such benefits should nevertheless be anticipated.
Solids—A great deal of difficulty was experienced in the laboratory
settling of the effluent samples from each stage of treatment in the
Phase II study. For example, the effluent from a particular stage might
settle fairly well while the effluent from the following stage might
settle very poorly. Also, the Imhoff cones would sometimes develop a
zone of clarified liquid between layers of solids-laden liquid. In any
case, it appears that the settling of stage effluents (and thus the
solids data and other performance data) were sometimes inconsistent
because of this laboratory problem.
A comparison of the ratio of total volatile solids to total solids
showed that the proportion of volatile solids decreased with additional
treatment. This indicates that as the waste was subjected to RBS
treatment, the solids were more highly stabilized with eachjdditional
stage of treatment. Also, at the higher flow rates the proportion of
volatile solids was greater than at lower flow rates, indicating that
there was less stabilization of solids at higher flow rates.
The suspended solids data (obtained by analyzing the laboratory
settled effluent of each stage) indicated a general trend toward
402
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increasing removals with increasing stages of treatment, although most
of the suspended solids removal obtained was associated with the first
stage of RBS treatment. Best suspended solids removals seemed to occur
for the corn-green bean wastewater.
Nitrogen and Phosphorus—Kjeldahl nitrogen, ammonia nitrogen and
nitrate nitrogen analyses were made on the influent and on all stage
effluents. The majority of the Kjeldahl nitrogen that was removed was
apparently associated with the influent settleable solids.
Nitrification was not expected, and was not observed during any portion
of the study.
Total phosphorus concentrations in the influent wastewater were
measured during the study. Limited information was available on
phosphorus removals, since effluent phosphorus levels were monitored
only during Phase I.
Canning wastewater is often said to be nutrient deficient from a
biological treatment viewpoint. It has generally been accepted that a
BOD:N:P ratio of 100:5:1 is required for biological treatment. However,
the BOD:N ratio was almost always greater than 100:5 (the average value
was approximately 100:3), and phosphorus was frequently less than 1
percent of the BOD during the study.
A correlation between low phosphorus and decreased BOD removals was
suspected, but the data were too limited to confirm this. In any case,
no supplementary nutrients were added to the process wastewater at any
time during the study. Additional work would be required to determine
if nutrient additions would enhance the RBS performance.
Lagplant
For the Phase II portion of the study, a third RBS pilot unit
(designated lagplant) was installed to treat the effluent from an
anaerobic lagoon at the Owatonna Canning Company. Operation of the
lagplant continued from August 11, 1974 to October 16, 1974. As with
the polyplants during Phase II, 24-hour composite samples were collected
by Minnesota Valley Testing and were analyzed by Hormel Laboratories.
Electrical power to the lagplant was provided by a diesel powered
generator located at the lagoon. Because of several power outages that
interrupted operation of the lagplant for periods up to several days in
length, some of the original data observation sets have been discarded.
Flow to the lagplant was maintained at 288 gallons per day until
September 17, when it was increased to approximately 715 gallons per
403
-------
day. Four-stage surface loadi'i,^ rates resulting from these flow rates
were 0.37 and 0.93 gallons per day per square foot.
Temperature— Inf 1 uent wastewater temperatures ranged from 10 degrees C
to 27 degrees C, with temperatures being noticeably lower after the
middle of September. Influent temperatures averaged 22.8 degrees C
during the period of August 11 to September 16 and 14.8 degrees C from
September 17 to October 17. Effluent temperatures fluctuated above and
below the influent temperatures but usually by no more than 1 degree C
to 2 degrees C.
Dissolved Oxygen—Dissolved oxygen concentrations in the lagplant
influentranged from 0.6 to 7.7 milligrams per liter with 1 to 2
milligrams per liter being most typical. Effluent DO levels were
usually 3 to 7 milligrams per liter higher than influent DO levels. At
the flow rate of 715 gallons per day the DO concentration frequently
dropped in the second stage, usually by 0.5 to 1.0 milligrams per liter.
JDH.---NO pH data were available for the lagplant pilot unit.
Biochemical Oxygen Demand—Total BOD5 concentrations in the lagplant
influent ranged from 340 to 1,180 milligrams per- liter. Day-to-day
fluctuations in BOD5 concentrations were lessened by the equalization
effect of the lagoon; however, there was a general tendency toward
gradually increasing and the decreasing BOD5 concentrations, the peak
BOD5 occurred near the middle of the' study and was undoubtedly the
result of corn and green bean processing.
Data collected on September 17 and 18 show a significant decline in
performance when the flow rate was increased followed by recovery to a
performance level somewhat lower than for the preceding lower flow rate.
BOD5 removal efficiency data as a function of surface hydraulic
loading rates for one, two, three and four stages are summarized in
Figure 13, in which average BODS removal efficiency is plotted with
hydraulic loading rate to show that BOD5 removal decreases with
increasing hydraulic surface loading rates.
As in the case of BOD5 removal, the COD data indicated (1) better
performance at low organic loadings, (2) better performance at low
hydraulic loadings, and (3) somewhat more consistent results with higher
number of stages of treatment.
Solids—The concentration of suspended solids in the settled effluent
from each stage was roughly the same as for the polypi ants. The percent
removal of suspended solids in the lagplant was less than for the
polyplants, possibly because the lagplant influent suspended solids
concentrations were lower.
404
-------
o
01
100 I
80
60
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Ul
IT
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at
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O 4 STAGES
O 3 STAGES
& 2 STAGES
O I STAGE
[ONE STANDARD DEVIATION
AVERAGE SOO REMOVED,%
1.0
Z.O
3.0
4.O
HYDRAULIC LOADING , gol/doy/ »q ft
Figure 13. Composite of hydraulic load - BOD removal ovservation averages for the lagplant
during RBS treatment of anaerobic lagoon effluent at Owatonna Canning Company.
-------
Settleable solids data were variable from day to day and from stage
to stage, but the existence of trends was not evident.
Total solids and total volatile solids data show increasing percent
removal with each additional stage and better removals at the lower flow
rate. The proportion of total volatile solids to total solids decreased
for each additional stage of treatment.
Nitrogen and Phosphorus—Removal of Kjeldahl nitrogen in the lagplant
was similar to the removal in the polypi ants. Ammonia nitrogen was
reported in 14 of the 21 influent samples, but no ammonia was present in
the fourth stage. Ammonia nitrogen may have been converted to nitrates
by nitrifying organisms, although the nitrate nitrogen data did not
confirm this. Nitrate nitrogen data show a few isolated occurrences of
nitrates but, generally, there was no nitrate nitrogen present in the
treated wastewater.
The average BOD:N:P value was approximately 100:4.8:1.8.
SUMMARY
Although the RBS system is a proven biological wastewater treatment
process in Europe, its capabilities have not been widely demonstrated
and accepted to date in America. Treatment of canning company process
wastewater has been and continues to be a difficult problem for the food
industry. The combination of these factors led to a one-season RBS
pilot plant study in Owatonna Canning Company in Owatonna, Minnesota.
Data collected during the study illustrate some of the parameters
which influenct the performance of the RBS process. The RBS process was
shown to be capable of treating wastewater under difficult and variable
loading conditions typical of food processing facilities.
Throughout the study, no attempts were made to control or modify
the variability of the process wastewater being treated. Although one
loses control of many critical variables with this approach, such
studies are an essential link between theory and practice. As a result
of this study, the RBS system seems to be worthy of consideration when
selecting a system to treat vegetable canning wastewater.
406
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A PRELIMINARY REPORT ON STUDIES TO DEVELOP ALTERNATIVE METHODS OF
REMOVING POLLUTANTS FROM TUNA (ALBACORE) PROCESS WASTEWATERS*
Harold J. Barnett**
Richard W. Nelson**
INTRODUCTION
Many commercial fish processors foresee difficulties complying with
newly promulgated water pollution control laws. Little is known about
controlling pollutants in fish processing wastewaters, and considerable
time and money have been invested by various governmental agencies and
the industry to determine feasible waste treatment methods.1>2>3'1*
Although some expertise has been developed, many problems remain to be
solved. In general, recommended treatment systems require considerable
land space which is seldom available to fish processing plants built
over water, or they require large and complex biological, chemical, and
mechanical systems that have not proven entirely satisfactory in pilot
or full-scale operations. Thus, the United States commercial fishing
industry finds itself in a potentially serious economic position as it
attempts to meet effluent guidelines with waste treatment methods that
have proven costly or are ill-defined.5 As a result, there is a need
for continued research to develop more effective and economic methods
for treating fish processing wastes.
For the past several years the Pacific Utilization Research Center,
National Marine Fisheries Service, has been involved at its main
laboratory in Seattle and its field laboratory in Kodiak, Alaska, on the
characteristics and control of pollution from seafood plant effluents.
Currently a pilot-scale waste treatment system that uses a relatively
inexpensive modified air flotation and double screening technique is
*Use of names does not imply endorsement but are used to facilitate
description.
**Pacific Utilization Research Center, National Marine Fisheries
Service, National Oceanic and Atmospheric Administration, US Department
of Commerce, 2725 Montlake Boulevard East, Seattle, Washington 98112.
407
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being evaluated in cooperation with Northwest seafood processors. As
designed, the pilot plant permits researchers to determine various
treatment operations on a systematic basis. That is, evaluations can be
made on the basis of coarse and fine screening, or dual screening in
combination with air flotation with or without the use of chemicals.
The unit is conveniently mobile and flexible as to arrangement and has
been used successfully in making pollution abatement studies in shrimp
and salmon canneries in the Pacific Northwest. At present, the modified
air flotation system is being evaluated in cooperation with a Northwest
seafood cannery as a method for treating tuna processing waste
effluents. The cannery operation is typical of the industry and
includes thawing, butchering, steam pre-cook, loin preparation, can
filling, and retorting. The waste streams are combined in a central
collection sump used as the source of wastewaters for these studies.
Although the work is not completed, preliminary data show promise.
METHODS
Modified Air Flotation Equipment
,i
Basic equipment making up the pilot plant are an 18-inch tangential
screen Bauer Hydrasieve (Figure 1), a 12-inch Sweco centrifugal
wastewater concentrator (CMC) (Figure 2), and a custom-made flotation
cell with a variable speed drive sludge removal system (Figure 3). The
flotation is equipped with a removal baffle that is used to help promote
flotation of solids. A portable air compressor is used to generate
dispersed air. Fine air bubbles are produced either by an aeration
device made of multiporous tubing or by adding compressed air directly
into the intake hose carrying screened effluent to the CWC. Assorted
variable-speed materials handling pumps and a holding tank complete the
major equipment needed to operate the pilot unit. Assembled for use,
the equipment appears in the configuration shown in Figure 4.
Chemicals
Chemicals used in these experiments were selected on the basis of
results reported in the literature as well as our own laboratory scale
jar tests. Although not exhaustive, these tests determined that"for the
purpose of coagulation and pH control alum, A12(SOJ3 and lime, Ca(OH),,
were most effective. The use of polymers was also investigated as a
potential flocculent to enhance removal of solids from the flotation
cell. Based on limited tests, a Betz anionic 1120 polymer was selected
for use in these experiments. Automatic feed pumps are used to mix the
chemicals with the effluents.
408
-------
Figure 1. Bauer hydrasieve.
409
-------
-------
Figure 3. Flotation cell
411
-------
MOYNO
PUMI
PLANT WASTE
SCREENED
SOLIDS
*»•
H*
to
BAUER
0.020 INCH
SCREEN
P-r--.
_ _l-flw*-^-*-*->>-V _ —'— — - - |
SWECO CENTRIFUGAL
WASTEWATER CONCENTRATOR (CWC)
SLUDGE
•AIR DIFFUSER
SKIMMED-^
EFFLUENT
DISCHARGE
Figure 4. Basic pilot plant equipment used in tests to remove solid
wastes from tuna cannery effluent.
-------
Flow Measurements
Flow rates related to the operation of the pilot plant were
determined by precalibrating variable speed drive pumps with known
volume containers and stop watch. Processing wastewaters discharged
from the plant were measured with a 1.5 foot model H-flume and an
Environmental Measurement Systems ultrasonic flow measuring device.6
The H-flume was selected because it is portable, relatively compact, and
has a rather wide flow rate capacity ranging from 0 to about 1,500
gallons per minute. The metering device was used because of its
portability, non-contact (not submerged) operation, and is remote or
line operated.
EXPERIMENTAL PROCEDURES
A total of six experiments were made in these preliminary studies.
Each experiment was divided into three or four unit operations which
included coarse and fine screening procedures, and screening operations
combined with air flotation and chemical treatment. Samples were taken
periodically during the experiments at each treatment step. These were
composited and analyzed according to standard procedures.7'8 The
experiments were based on continuous runs lasting from 1 to 4 hours of
operation each.
RESULTS AND DISCUSSION
The data in Table 1 show the results of the tests using the
modified dispersed air flotation equipment. The values given are
averages of replicate analysis. In the first unit treatment tests,
plant effluent was screened by the tangential screen (line 2 of Table
1). Significant reductions in the three parameters measured were
observed. A 0.010-inch screen (50 mesh equivalent) was used in these
tests. The screen was selected on the basis of tests comparing the
settleable solids content in the underflow from a 0.020-inch and 0.010-
inch screens. The 0.010-inch screen was found to be about 10 percent
more efficient than the 0.020-inch screen. No blinding problems were
encountered with the finer screen. In the second stage of testing the
centrifugal wastewater concentrator was used in combination with the
tangential screen. Although the removal of additional suspended solids
was observed, (line 3 of Table 1) no significant reductions were
achieved in BOD and in oil and grease. Failure to reduce these
parameters can be attributed to the fact that a considerable part of the
BOD5 comes from dissolved soilds which cannot be removed by screening.
In addition, the warm processing water temperature (70 to 95 degrees F)
413
-------
Table 1. EFFECT OF SYSTEMATIC SCREENING AND AIR-FLOTATION
TREATMENT OF TUNA CANNERY EFFLUENT
Treatment
Unscreened effluent
Hydra. -si eve screened
Hyd. + CWC screened
Hyd. + CWC chemical
treatment and
flotation
Parameters
pH
6.2
6.2
6.2
8.3
TSS,
ppm
2,624
1,835
1,060
124
%
red.
-
30
59
95
BODs,
ppm
4,960
2,890
2,625
1,013
%
red.
-
42
47
80
O&G
ppm
2,401
1,197
1,036
126
%
red.
-
54
57
95
414
-------
partly solubilizes the oils making them also difficult to screen. The
CMC was equipped with 165 mesh screens for these studies.
At this point in our studies tests were made to evaluate the
combination of double screening and dispersed air flotation without the
use of chemical coagulants as a means of further reducing
biodegradeables. Results from these tests indicated that the procedures
did not appreciably lower the concentration of solids waste more than
could be accomplished with the double screening procedure. Because no
significant differences were observed, these test results are not
included in Table 1. Final treatment procedures included double
screening combined with dispersed air flotation and addition of
chemicals. Maximum results were achieved using chemical concentrations
of 20 parts per million alum and 150 parts per million lime. Clagget
and Wong9 made similar observations in their studies with salmon
wastewaters. Polymer was used at a concentration of 5 parts per
million. Compressed air was used continuously at a rate of about 2
standard cubic feet per hour (SCFH). Results of these tests are shown
in the bottom line of Table 1. In addition to the removal of the
parameters given in the table, we also observed significant
clarification of the plant effluent by the final treatment step.
Reduction in turbidity (Formazin Turbidity Units) were consistently 98
percent. Generally, floe occurs simultaneously as the waste stream
enters the flotation cell resulting in a rapid-forming sludge blanket.
Formation of the blanket is further facilitated by aeration resulting
from centrifugal screening and the addition of dispersed air. Mo
attempt was made in these preliminary tests to handle the cencentrate
from the CMC or the sludge removed from the flotation cell. However,
the sludge was analyzed and found to have the chemical composition shown
in Table 2.
The results presented in this report indicate that the dispersed
air flotation technique described has considerable potential for
removing pollutants from tuna processing effluents. However, additional
research is essential in the following areas to make the system
complete: (1) separation (dewatering) of the solids from the sludge and
concentrate, (2) finding use for these solids, (3) evaluation of methods
such as recycling treated wastewater to decrease use of chemical
additives, and (4) evaluation of methods for removing additional
dissolved solids from treated flotation effluent.
Before these and similar research approaches could be considered
for commercial use, it would also be necessary to design a total system
that would handle each step in the operation. A thorough study of the
economic feasibility of the final system is necessary.
415
-------
Table 2. CHEMICAL COMPOSITION OF SLUDGE REMOVED
BY DISPERSED-AIR FLOTATION WITH CHEMICAL
TREATMENT OF TUNA CANNING EFFLUENT
Constituent
Moisture
Grease and oil
Protein
Salts (alum,
lime)
Wet weight, %
86.3
8.4
2.0
3.3
Dry weight, %
-
61.3
14.6
24.1
416
-------
REFERENCES
1. Horn, C. R. Characterization and Treatabilicy of Selected
Shellfish Processing Wastes. Special research problem, School of
Engineering, Georgia Institute of Technology, Atlanta. 1972.
2. Mauldin, A. F. and A. J. Szabo. Shrimp Canning Waste Treatment
Study. EPA Project Number S800904. Office of Research and
Monitoring, US Environmental Protection Agency, Washington, DC.
1974.
3. Claggett, F. G. Clarification of Fish Processing Effluents by
Chemical Treatment and Air Flotation. Fish. Res. Board of Canada.
Technical Report Number 343. 1972.
4. De Camp, R., D. E. Brooks, and D. M. Crosgrove. Air Flotation
Treatment of Salmon Processing Wastewater. National Canners
Association, Northwest Research Laboratory, Seattle, Washington.
1969.
5. Whitaker, D. R. Environment Law May Close Many USA Fish Factories.
Fishing News International. February 1975.
6. Orkney, J. B. The Application of Ultrasonic Liquid Flow Measure-
ment for the Water and Wastewater Control Industry. Environmental
Measurements Systems, Western Marine Electronics., Inc., Seattle,
Washington. Form Number EMS 159-474A.
7. US Environmental Protection Agency. Methods for Chemical Analysis
of Water and Wastes. EPA National Environmental Research Center,
Analytical Quality Control Laboratory, Cincinnati. 1971.
8. American Public Health Association. Standard Methods for the
Examination of Water and Wastewater. 13 edition. 1971. p. 367-
577.
9. Claggett, F. G. and J. Wong. Treatment of Fish Processing Plant
Wastewater. Fish. Res. Board of Canada. Bulletin Number 189.
1974.
417
-------
EFFLUENT VARIABILITY IN THE MEAT-PACKING
AND POULTRY PROCESSING INDUSTRIES
James F. Scaief*
INTRODUCTION
Increased industrialization has resulted in higher waste loadings
on receiving bodies of water and has caused regulatory agencies to
require increasingly more stringent effluent standards. These
standards, in addition to five-day biochemical oxygen demand (BOD5) and
total suspended solids (TSS), include parameters such as ammonia-
nitrogen (NH3-N), oil and grease (O&G), fecal coliform, and pH.
Tables 1 and 2 summarize the guidelines established for the red
meat industry and recommended for the poultry processing industry.
For many meat-packing and poultry processing plants to meet these
new guidelines, much needs to be accomplished in controlling their
effluent variability. As stated by Ford,1 an inherent variability is
attributed to the treatment system, the characteristics of the raw waste
load, and geographical and climatological conditions. Therefore, to
minimize the variability one needs to take a look at each factor
contributing to this variability and determine what control measures are
possible. Analyses of in-plant processes will be necessary and in some
cases newer processes may have to be introduced. Provisions might be
made to minimize storm water runoff entering the system. The existing
guidelines and the probable inclusion of nutrients in effluent standards
will, in many cases, require the industries to install further treatment
beyond existing secondary treatment. If an industry elects to discharge
to a municipal system, pretreatment might be required.
*US Environmental Protection Agency, Industrial Environmental Research
Laboratory, Corvallis Field Station, Corvallis, Oregon.
418
-------
Table 1. RED MEAT EFFLUENT STANDARDS0
(kg/kkg LWK)
CO
Plant
Subcategory
Slaughterhouse
I. Simple
II. Complex
Packinghouse
III. Low-Processing
IV. High-Processing
7/1/77
Best Practical Treatment
BOD 5
0.12
0.21
0.17
0.31
TSS
0.20
0.25
0.24
0.31
O&G
0.06
0.08
0.08
0.13
New Sources
NH3-N
0.17
0.24
0.24
0.13
7/1/83
Best Available Treatment
BOD 5
0.03
0.04
0.04
0.08
TSS
0.05
0.07
0.06
0.10
aFederal Register, Volume 39, Number 41, February 28, 1974. Maximum average of daily
values for a 30 consecutive day period.
Notes: pH limit is 6.0 to 9.0
Fecal coliform maximum limit is 400 mpn/100 ml.
Maximum for any 1 day is 2 times the average.
1983: O&G, maximum = 10 mg/1
NH3-N maximum = 8 mg/1
-------
Table 2. POULTRY PROCESSING: RECOMMENDED EFFLUENT LIMITATIONS3
Average Limitation
(kg/kkg LWK)
to
o
Plant
Subcategory
Chickens
Turkey
Fowl
Ducks
7/1/77
Best Practical Treatment
BOD 5
0.46
0.36
0.61
0.77
TSS
0.62
0.57
0.72
0.90
O&G
0.20
0.14
0.15
0.26
7/1/83
Best Available Treatment
BOD5
0.30
0.21
0.23
0.39
TSS
0.34
0.24
0.27
0.46
O&G
0.20
0.14
0.15
0.26
aEPA Contract Number 68-01-0593
Notes: Fecal coliform maximum limit is 400 mpn/100 ml
NH3-N: New Source and 1983 limit is 4 mg/1.
1983: TKN = 4 mg/1
TP = 2 mg/1
N03/N02-N = 5 mg/1
-------
Through analysis of data from existing outstanding meat packing,
slaughtering and poultry processing plants, it is hoped to identify
those combinations of in-plant controls and subsequent wastewater
treatment processes which are most efficient in meeting discharge
regulations.
Primary objectives:
1. Determine in-plant controls which produce least magnitude and
variability in treated effluent loads.
2. Determine treatment system or systems used to produce least
magnitude and variability in effluent loads.
3. Determine what percentage of time plant discharge meets
established effluent limits.
4. Determine causes when limits are exceeded.
5. Determine the level beyond which a treatment plant ceases to
provide effective treatment.
Information needed:
Records on:
1. Production
2. Effluent flow
3. Effluent compositions
a. Untreated
b. Treated
4. In-plant process description
5. Treatment plant design
RESULTS
Data Search
Data was obtained for this project from individual state pollution
control agencies, the United States Department of Agriculture, North
Star Research Institute, and private industry in addition to the
Environmental Protection Agency.
Initially it was decided that in order to have a meaningful
statistical analysis, at least 40 data points for the various wastewater
quality parameters would be needed. This alone limited the number of
plants for which data would be available.
Due to the lack of a regular reporting system in many states, only
those plants that were believed to be producing a poor quality effluent
421
-------
were monitored regularly. This study is concerned with the more
exemplary plants, and consequently there is little information
available. Originally it was intended to evaluate the treatment systems
with respect to biochemical oxygen demand, chemical oxygen demand,
suspended solids, oil and grease, ammonia nitrogen, and phosphorus. It
was found that data on parameters other than BOD5 and SS was very
limited, and as a result, comparison of the different types of treatment
systems with respect to the other parameters was not possible.
Meat: RawWastewater
Table 3 shows the mean water use as well as raw BOD5 and SS
wastewater loads from meat-packing plants. The two plants showing the
lowest mean values for BOD5 and SS are 8A and 9A with values of 10.2 and
8.1 kilograms BOD5 per 1,000 kilograms and 10.0 and 8.4 kilograms SS per
1,000 kilograms live weight killed (LWK), respectively. Another plant,
1A, even though the mean BOD5 and SS loads are not quite as low, does
exhibit a variability that is minimal as can be seen by the standard
deviations. At the other end of the scale are plants 3A and 7A with raw
wastewater loads of 23.7 and 18.0 kilograms BOD5 per 1,000 kilograms LWK
and 17.7 and 14.4 kilograms SS per 1,000 kilograms LWK, respectively.
Figures 1 and 2 show probability curves developed to graphically show
the variability of the effluent.
It is difficult to pinpoint the reasons for the lower wasteloads
without conducting an in-plant survey; therefore, conclusions have to be
drawn based on the processing plant raw waste!oad. For the above
plants, one feature that might explain the differences is water use. In
Table 3, plants 1A, 8A, and 9A, the three plants with the lowest water
use for Category II, are also the ones mentioned above exhibiting the
least raw wastewater load. Plant operations that could contribute
toward this lower water use are better housekeeping practices and making
use of dry cleanup prior to washdown. Another significant factor in
water use reduction is the installation of high pressure nozzles on
water outlets.
Meat: Final Effluent
Results of different treatment system employed in the meat-packing
industry are presented in Table 4. All make use of a biological
secondary system, either an anaerobic-aerobic lagoon system or an
anaerobic contact process followed by aerobic lagoons.
As can be seen from the aforementioned table and Figure 3,
comparing the results with the effluent limitations presented
previously, only one of the plants could not meet the 1977 mean BOD5
422
-------
Table 3. RAW WASTEWATER CHARACTERISTICS
to
CO
Plant
1A
3A
4A
7A
8A
9A
Effluent
guidelines
category
II
II
III
II
II
II
BOD5a
Mean
10.7
23.7
12.0
18.0
10.2
8.1
Max.
18
33
23
45
21
15
Std.
dev.
3.8
4.9
7.8
10.6
5.3
3.1
Nb
45/26
34/12
49/37
33/17
91/24
42/11
ssa
Mean
12.8
17.7
13.0
14.4
10.0
8.4
Max.
24
27
27
36
21
16
Std.
dev.
4.5
3.1
13
10
6.4
7.5
N
46/26
35/12
48/37
30/17
91/24
53/11
Water
use0
4.38 (525)
15.60 (1,870)
8.29 (993)
9.27 (1,111)
7.89 (946)
8.44 (1,012)
aValues in kg/kkg LWK.
N = number of observations/number of months in observation period.
Slater use in m3/kkg (gal./I,000 Ibs).
-------
to
1ft! MEAN=10,7 RSQ=.B78
3A: MEAN=23.7 RSQ=.971
4ft! MEAN=12.0 RSQ=.911
7ft: MEAN=18.0 RSQ=.9BB
BR: MEAN=ia.2 RSQ=,990
9ft! M£AN= 9.1 RSO=.38«
•4-
•4-
10 20 20 40 50 80 70 80 90
PROBABILITY (* OF VALUES LE CORRESPONDING LOAD)
x
+
i
Figure 1. Log-Probability representation of meat-packing plant raw BOD5 waste load.
-------
fe
Ul
is
•"•*
2B.QOO .
o
1B.QQQ
a
a
a
T-H
Q
-------
Table 4. FINAL EFFLUENT CHARACTERISTICS
to
as
Plant
1A
3A
4A
7A
8A
9A
Effluent
guidelines
category
II
II
III
II
II
II
BOD5a
Mean
0.13
0.11
0.16
0.33
0.14
0.21
Max.
0.58
0.23
0.55
1.45
0.46
0,62
Std.
dev.
0.13
0.06
0.10
0.26
0.10
0.15
Nb
43/27
29/14
32/36
49/29
92/24
42/11
ssa
Mean
0.33
0.30
0.67
0.34
0.43
0.44
Max.
2.31
1.15
1.95
1.52
1.55
1.56
Std.
dev.
0.37
0.22
0.47
0.34
0.32
0.31
N
46/27
29/14
28/36
46/29
92/24
53/11
aValues in kg/kkg LMK
N = number of observations/number of months in observation period.
-------
O
DO
3 -80
S -60
o> -40
~ -20
0-0
CT
Q
O
_J
CO
1-6
1-4
1-2
1-0
•80
•60
•40
•20
0-0
KEY:
guidelines
avg. ~*-~
actual avg?
1
2-3
•actual max.
-guidelines max.
1-45
rl
i
1-95
i
n
1
A 3A 4A 7A
PLANT
8A
I
^
9A
Figure 3. BOD5 and SS actual versus 1977 guidelines 30-day average and
daily maximum.
427
-------
limits for its respective category and the maximum-value was exceeded by
five of the six. Figures 4 and 5 show probability curves developed to
graphically show the BOD5 variability of the effluent.
From Figures 3, 6, and 7, it can be seen that of the plants under
consideration in this evaluation, none were able to meet either the 1977
mean or maximum suspended solids limits. Plants 1A, 3A, and 7A were
closest to meeting the 0.25 kilograms per 1,000 kilograms LWK average
limit, but none were near the established maximum value.
It should be noted that the average reported for each of the plants
is a long-term average and not the maximum average for a 30-day period
as specified in the guidelines. Because past monitoring policies were
not established to meet the present system of effluent limitations, it
was believed that reporting the data as a maximum average for a 30-day
period did not truly reflect the capabilities of the treatment system.
This was considered, but in some cases with infrequent sampling, the
maximum average for a 30-day period approached the maximum daily value.
In other cases, with more infrequent sampling, the maximum average for a
30-day period was in fact less than the long-term average.
The treatment system employed by plant 3A produced the lowest mean
and maximum BOD5 and suspended solids loads of the six meat-packing
plants. This system consisted of an anerobic contact process and
anaerobic-aerobic stabilization ponds. As mentioned previously, all
others made use of an anaerobic-aerobic lagoon system.
Since there is a lack of diversity and number in the type of
treatment system employed, no attempt is made to judge one system type
better than another. Of the ones represented here, the ability of one
to perform more effectively than the other is assumed then to be based
on the operation of the plant.
An attempt was made to determine the cause of the occasions when
the maximum allowed limits were exceeded. This was done using what
information was available in regard to weather conditions and plant
processes. The extent of the data varied widely from plant to plant.
In some cases, when data permitted, an attempt was made to determine if
the treatment plant was operating under normal loading or if some in-
plant upset occurred which might affect the treatment system. Weather
data, extremes in temperature and periods of high rainfall were
variables for which data was more readily available that might ' aid in
drawing some conclusion as to the operation of the treatment plant.
Beginning with plant 1A and making use of the basic data, events of
high effluent load, both BOD5 and suspended solids, are presented when
available in Table 5 with an explanation of the prevailing operating
conditions.
428
-------
to
CO
^ 1.000
-J
o
CJ
a
a
a
-------
co
o
.300
.200 . .
.ioa
CJ>
o
o
o
Q
-------
co
: M£AN=.33
3A: MEftN=.3Q
7A: MEAN=.3-4
9A: MEftN=.-13
9A:
RSQ',.955
R5Q:,3BB
RSQ.-.93B
RSQ:.S55
-4-
•4-
X
+
I
10 20 3Q 40 50 60 70 BO 90
PROBABILITY U OF VALUES LE CORRESPONDING LOAD)
Figure 6. Log-Probability representation of meat-packing plant final effluent SS waste
load, Category II plants.
-------
co
to
1.500
O 1.000
O
o
o
O
is:
N— *
Q
-------
Table 5. HIGH EFFLUENT LOAD OPERATING CONDITIONS
Plant
1A
4A
7A
8A
Effluent
parameter
BOD 5
SS
BOD 5
SS
BOD 5
SS
BOD5
SS
Date
02/10/72
02/24/72
03/09/72
05/17/71
04/24/74
05/17/71
04/17/72
01/25/73
07/13/73
05/24/74
06/20/72
10/24/72
04/23/74
05/11/72
11/08/72
11/15/72
05/04/72
06/15/73
Condition
Period of sub-zero temperature, snow,
and treatment plant overloaded.
Temperature near or below freezing, no
overload.
BOD5 70 mg/1 (20 mg/1 > influent to
final lagoon), flow and production
normal .
BOD5 50 mg/1, second highest reported
between 03/71 and 04/74^
SS 250 mg/1 (200 mg/1 > influent to
final lagoon).
SS 240 mg/1 (110 mg/1 > influent to
final lagoon).
Final flow > normal.
Final flow > normal .
Final flow > normal .
Rain, final flow normal.
2" rain in previous 2 days, high flow,
SS 133 mg/1 .
2%" rain, high flow, SS 140 mg/1.
Rain, final flow > normal.
Flow > normal .
Flow > normal .
1" rain, flow > normal .
Flow > normal, SS 136 mg/1.
433
-------
From looking at those conditions, it is assumed that extremes in
weather affected the performance of the lagoon systems used in the
plants. For plants 1A, 7A, and 8A, all periods of ineffective operation
coincided with either unusually cold weather or periods of high rainfall
which produced an effluent flow greater than normal. These unusual
operating conditions account for the occasions when the established 1977
effluent limitations were exceeded.
Table 6 shows the frequency of occurrence of values less than or
equal to the 1977 mean and maximum effluent limitations based on the
predicted curves of Figures 4 through 7. Plants 1A, 3A, and 7A are the
only ones that might be capable of meeting the mean or 30-day average
limitation for suspended solids. Of these plants the maximum limitation
can only be met up to 85 percent of the time. The other 15 percent
would be out of compliance.
Poultry: Raw Wastewater
Table 7 shows the mean raw BOD5 and SS wastewater loads from
poultry processing plants. Raw wastewater quality data was very limited
with only two of the plants having BOD5 data and one with SS data. The
two, both broiler processing plants, were quite different in terms of
raw waste load, 6.4 versus 36.7 kilograms per 1,000 kilograms LWK.
Figures 8 and 9 show the variability of the raw waste load on a
proability basis. One factor that would account for part of the
variation in the load between the two plants is that plant 2B does not
engage in further processing or rendering. However, the low wastewater
load of plant 2B should merit further attention. Shown also in Table 7
is the water use by the four poultry processing plants in this study.
Carawan et al.2 concluded that lower water use in a poultry processing
plant reHuces the raw wastewater load. Plant 2B instituted a water
conservation program in which the use dropped from approximately 42 to
26 liters per bird. Water reduction measures consisted of an employee
awareness program, daily inspections, elimination of piping leaks and
the use of hoses where possible, and automatic shut off valves on
essential hoses. Supply lines were equipped with valves to allow for
flow regulation. Dry cleanup was practiced prior to washdown with a
portable high pressure cleaning system. Lastly, chill vat water was
recycled for reuse in the scalder. It is assumed, based on Carawan1s
earlier conclusions, that the water conservation measures undertaken by
plant 2B are largely responsible for the lower raw waste load of the
plant.
As an additional note plant 3B, the other plant with low water use,
instituted water conservation measures. These consisted of a water
pressure reduction from 414 to 138 kilonewton per square meter (60 to 20
pounds per square inch), installation of spray type hand washers, use of
434
-------
Table 6. FREQUENCY OF OCCURRENCE OF VALUES <. 1977 EFFLUENT LIMITATIONS
(From predicted curves, in percent)
Plant
1A
3A
4A
7A
8A
9A
BOD 5 v
Mean
82
89
68
38
80
64
Max.
93
100
96
78
95
87
SS
Mean
56
57
25
54
44
28
Max.
82
82
55
82
71
68
435
-------
Table 7. RAW WASTEWATER CHARACTERISTICS
00
Effluent
guidelines
Plant category
2B Broiler
3B Duck
5B Broiler
6B Broiler
BODsa
Mean
6.4
-
-
36.7
Max.
15
-
-
52
Std.
dev.
2.2
-
-
11.8
Nb
62/8
-
-
10/5
ssa
Mean
12
• -
-
-
Max.
41
-
-
-
Std.
dev.
7.0
-
-
-
N
61/8
-
-
-
Water
usec
26.0 (6.9)
26.7 (7.06)
67.4 (17.8)
42.8 (11.3)
^Values in kg/kkg LWK.
bN = Number of observations/number of months in observation period.
Slater use in liters/bird (gal./bird).
-------
co
•40.000
30.000
20.000
a
o
o
CJ5
10.000
5.000
O
-J
CD
cc
u
h-
-------
CO
oo
30.000
-J
20.000
a
a
a
10.000
O
•J
C/l
l/l
a:
LU
h-
-------
high pressure-low water systems in clean-up, and cutoff in flow-through
system to stop water flow when lines are not running.
Poultry; Final Effluent
Table 8 summarizes the results of treatment systems employed in the
poultry processing industry. Biological secondary systems used are
aerated lagoons, anaerobic-aerobic lagoons, and activated sludge.
Due to the guidelines regarding effluent limitations not being
finalized at the time of this writing, the results obtained by the
plants in this study are compared to the 1977 values recommended by the
contractor to EPA. These are not to be taken as a limit, but only a
value from which to compare the results obtained here. As with the
meat-packing plants, the averages presented are the long-term averages
and not the maximum average for a 30-day period.
Of the four plants presented, two of the recommended categories are
represented. These are the duck processor and the broiler processor
with one of the broiler processors (6B) engaged in further processing
and rendering.
Table 8 and Figure 10 show that two of the broiler processors and
the duck processor would meet the average BODs limits. The maximum
daily value of the plants within the recommended average varies in the
range of 1.8 to 4.2 times the mean obtained by these plants. Based on
the recommended averages of 0.46 and 0.77 kilograms BOD5 per 1,000
kilograms LWK for plants 2B and 3B, respectively, the maximum would be
3.7 and 0.73 times the average. Plant 3B is a case where the values are
so low as to make the maximum less than the recommended average. Plant
6B, with the maximum 4.1 times its average or 1.7 times the recommended
average is a special case since this plant also handles further
processing and rendering operations. Though it would meet the more
stringent BODs limit for a normal broiler processing plant, its mean
value of 0.29 kilograms per 1,000 kilograms LWK would readily be in
compliance with the 0.72 kilograms per 1,000 kilograms LWK recommended
limit based on an adjustment factor for the ancillary operations.
Figures 11, 12, and 13 show the probability curves developed to
graphically show the BODs variability of the effluent for these plants.
Table 8 also shows the suspended solids levels obtained by all the
plants except 6B and these are compared to the recommended limits in
Figure 10. Only one of these (3B) was able to meet the recommended
limits and it did so readily, with the maximum of 1.35 kilograms per
1,000 kilograms LWK being greater than the recommended average of 0.90
kilograms per 1,000 kilograms LWK by a factor of 1.5. Figures 14 and 15
439
-------
Table 8. FINAL EFFLUENT CHARACTERISTICS
Plant
2B
3B
5B
6B
Effluent
guidelines
category
Broiler
Duck
Broiler
Broiler
BOD5a
Mean
0.40
0.18
0.67
0.29
Max.
1.7
0.56
1.2
1.2
Std.
dev.
0.35
0.11
0.27
0.24
Nb
102/11
46/27
36/5
68/8
SS
Mean
1.0
0.32
1.61
-
Max.
3.5
1.35
4.8
-
Std.
dev.
0.79
0.23
1.33
-
N
102/11
47/27
28/5
-
^Values in kg/kkg LWK.
DN = Number of observations/number of months in observation period.
-------
Q
O
O
CD
Q
<
O
_J
CO
CO
1-2
•80
•40
O.n
•u
5-0
4-0
3-0
2-0
1-0
-
_
_
—
-
-
zz
1
H
•7
1^
Vv
1
ll
£2
r —
f
1
•HIHHIH
^
%
%
1
^
P
^•actual
., .. max.
guidelines
QVg, ~i. ,
actual avgf
2B 3B .58
PLANT
6B
Figure 10. BODs and SS actual mean and maximum versus 1977
recommended guidelines mean.
441
-------
to
1,500
i.oaa
.500 ..
.LQ3
.050 ..
-J
o
a
a
a
-------
co
-j
CD
a
a
a
•M
X.
CJ>
a
<£
o
Q
o
aa
LU
D
.J
LL
U.
UJ
.700
.BOO
.50(1
MFfaM I TMTT
.200 .
.100
.050 ..
.010
38.-
RSQ=.S77
10 20 30 40 50 60 70 80 30
PROBABILITY CB OF VALUES LE CORRESPONDING LOAD)
Figure 12. Log-Probability representation of a poultry processing plant final effluent BOD5
waste load, duck category.
-------
*>•
he-
1.000
.500 ..
.100
.050 .
68: MERN=,29 RSQ=.959
.j
o
o
o
•M
\
Us
Q
-------
•4.000
3.030
01
2B: MEftN=1.0
SB; MEnN=i.B
10 20 30 -40 50 BO 70 BO SO
PROBABILITY U OF VALUES LE CORRESPONDING LOAD)
Figure 14. Log-Probability representation of poultry processing plant final effluent SS
waste load, broiler category.
-------
_J
o
o
Q
o
">•->
Q
O
_J
in
UJ
D
.J
LJ.
U_
LJ
-J
-------
graphically show the suspended solids variability by the use of
probability plots.
The treatment system employed by plant 3B consists of in-plant
screening followed by three aerobic lagoons in series. This plant also
made use of extensive water conservation practices as mentioned earlier.
Plant 68, producing a low BODs load, also is capable of effective
suspended solids treatment. Sufficient data was not available to
properly evaluate it, but it has been able to produce an effluent
suspended solids of 5 milligrams per liter. This system consists of a
grease trap, wet well, holding tank, chemical mixing, flotation,
activated sludge, two-parallel microstrainers, and a chlorine contact
tank.
As with the meat-packing plants an attempt was made to determine
the cause for the extremely high values. Information on weather
conditions and plant processes is not as complete as meat-packing plants
and there is adequate data on only one plant, 3B. Table 9 presents the
periods of high effluent loads with an explanation of the prevailing
operating conditions. In all cases of high effluent BODs or SS loads
there also existed an unusual weather condition, either heavy rainfall
or high wind. This plant has since made provisions to eliminate
rainfall runoff from its treatment system.
Table 10 shows the frequency of occurrence of values less than or
equal to the 1977 mean effluent limitations based on the predicted
curves. Plants 2B, 3B, and 6B are capable of meeting the mean BODs
effluent limitation with at least 72 percent of their values being lower
than the recommended mean. For 3B and 6B, this values increases to 92
and 100 percent, respectively. With respect to suspended solids, only
3B falls within the recommended average greater than 5 percent of the
time, in this case 100 percent. It is noted again that there was not
sufficient data to evaluate plant 6B for SS.
Winter-Summer Variation of Treated Effluent
Both the meat-packing and poultry processing plants were tested for
any winter versus summer variation. The summer being classified as May
through October. The means and variances were tested for equality at a
confidence level of 95 percent. Table 11 shows the results of the
statistical tests performed on the means and variances. No clear
pattern could be detected for the variation. Plants 1A and 4A, which
both meet the 1977 BODs limits but not the suspended solids limits, were
the only meat-packing plants meeting the test for the equality of the
means. Plant 4A also meets the criteria for equality of the variances
at a 95 percent confidence level. All other meat-packing plants fail
447
-------
Table 9. HIGH EFFLUENT LOAD OPERATING CONDITIONS
Plant
3B
Ef f 1 uent
parameter
BOD5
SS
Date
08/09/72
06/25/73
09/05/73
08/09/72
08/28/72
10/09/72
Condition
Heavy rain, high runoff.
Heavy rain, muddy outlet.
High discharge, affected by
summer rainfall .
Heavy rain, high runoff.
High wind, SS > 100 mg/1 .
Heavy rain.
Table 10. FREQUENCY OF OCCURRENCE OF VALUES < RECOMMENDED
1977 EFFLUENT GUIDELINES
(From predicted curves, in percent)
Plant
2B
3B
5B
6B
Mean BOD5
65
100
25
100
Mean SS
35
100
25
-
448
-------
Table 11. RESULTS OF STATISTICAL TESTS FOR WINTER-SUMMER
EQUALITY OF MEANS AND VARIANCES*
Plant
1A
4A
7A
8A
9A
2B
6B
Results
1010
1111
0000
0101
0100
1111
11—
Tests conducted at a 95% confidence
level; "1" implies meeting the test,
"0" does not; first two digits relate
to BOD5 mean and variance, second two
are for SS.
449
-------
the test except for 3A which did not have sufficient data for
comparison.
Plants 2B and 6B, the two poultry processors tested for any winter-
summer variation, both met the tests for equality of the means and
variances with respect to any BODs or suspended solids variation except
for 6B which had no suspended solids data. With respect to ability to
meet the 1977 recommended effluent limitations, plants 2B and 6B readily
met the BODs guidelines, but 2B is not able to meet the suspended solids
limits.
SUMMARY AND CONCLUSIONS
The results on the raw waste load tend to support conclusions
reached by Carawan2 that lower water use reduces the raw waste load.
Plants that instituted a water use reduction program also had a
corresponding wastewater load reduction.
On a long-term basis, the meat-packers appear to be capable of
meeting the 1977 limitations on BOD5, but for suspended solids the
maximum daily value is critical. Of the six plants in this study, the
most effective one exceeded the maximum suspended solids limitation 15
percent of the time.
Based on the recommended guidelines for the poultry processing
industry, there are plants in existence that can readily meet the 1977
BOD5 and suspended solids limitations. The 1983 BOD5 average limits are
being met by two of the plants, a duck processor and the broiler or
chicken processor that engages in further processing and rendering. The
duck processor is also able to meet the 1983 maximum BOD5 and average SS
limitations assuming the maximum limit will be established as two times
the average.
For both the meat-packer and poultry processor, periods of high
effluent load coincided with periods of abnormal weather conditions. In
the case of the meat-packing plants, where sufficient data was
available, all occasions of exceeding the maximum limitation were
accompanied by severe weather conditions.
Of the plants evaluated in this study, there is no conclusive
evidence as to the variability of the effluent with respect to winter-
summer. Overall performance of a treatment plant appeared to have no
effect on the variability with respect to the seasons.
Due to lack of diversity and number, it was not possible to
comparatively evaluate the effectiveness of the treatment systems. For
450
-------
the meat-packing industry, both treatment systems of an anaerobic
contact system followed by aerobic stabilization ponds and anaerobic-
aerobic lagoon systems were similarly effective. For the poultry
processing industry, effective treatment was provided by three different
biological secondary systems: aerated lagoons, anaerobic-aerobic
lagoons, and activated sludge. The wastewater management systems
employing the aerated lagoons (three in series) and the activated sludge
were more readily able to meet the recommended effluent limitations.
The latter system consisted of a grease trap, wet well, holding tank,
chemical mixing, flotation, activated sludge, two-parallel
microstrainers, and a chlorine contact tank.
Inferences drawn from the plots of the effluent load versus
frequency for the meat-packing and poultry plants are that in order to
stay within the maximum limitations, an average less than the 30-day
average limit will be necessary. This is due to the fact that the
maximum value of the effluent load is greater than twice the average
load. Some plants, as in the case of BOD5 for 6B, even though the
maximum value is greater than two times the mean, both fall within the
average and maximum limits due to the low average value. Since a plant
such as this is weighted more heavily in the lower range of values, it
is to be expected that the maximum would be greater than two times the
average due to the range of effluent loads inherent to the system.
Relating the results to the enforcement of the established guide-
lines would lead one to question the enforceability of the maximum
limit. Using the system of Plant 1A, the maximum allowed BOD5 value was
exceeded only one time in 43 samples. For monthly or weekly samples
this would result in a probability of sampling on a day that the maximum
was exceeded of only 2 x 10"9 and 5 x 10~5, respectively. See Appendix
for calculation. In any plant that exceeded this limit frequently
enough to cause enforcement action, the high results would increase the
mean such that enforcement of these extreme values would be covered in
the mean.
This leads to a system proposed for one by Pope!3 in which a
combined standard would be established with a set limit and an allowed
probability of exceeding it. To illustrate this concept, the results of
plant 6B are plotted again in Figure 16 as in Figure 13, except this
time using an arithmetic scale. This more effectively shows the point
at which the treatment efficiency falls off. The combined standard
would set the limit at this point, or the 90 percent level in this case.
This would allow for the few occasions of the less effective plant
operation that might be due to weather conditions, but in actuality
would closely represent the true performance of the treatment system for
a major percentage of the time.
451
-------
Oi
to
SB MEftN=.23 R SQ=.99 x
ID 20 jO «10 ! 50 EO 70 SO
PROBABILITY (5*OF- VALUES LE CORRESPO\'DirxG LOPD)
30
Figure 16. Arithmetic representation of Plant 6B final effluent BOD5 load and frequency
of occurrence.
-------
ACKNOWLEDGEMENTS
This paper was a result of an in-house project and two Corvallis
EPA personnel deserve special acknowledgement. Judy Carkin for her role
in the computer analysis and Jack L. Witherow for his suggestions made
during the course of the project.
In addition to private industry, several individuals were
instrumental in providing data for the project. These are:
Jeffery D. Denit E. E. Erickson
Effluent Guidelines Division, EPA North Star Research Institute
Jim Chittenden Don Dencker
National Independent Meat American Meat Institute
Packers Association
Dr. Arnold Giesemann John Schmidt
US Department of Agriculture, Pennsylvania Department of
APHIS Environmental Resources
Brian J. Holmes Russell C. Felt
Virginia State Water Control Board Minnesota Pollution Control
Agency
Philip R. O'Leary Tom Wall in
Wisconsin Department of Natural Illinois EPA
Resources
Richard Rankin
Iowa Department of Environmental
Quality
453
-------
REFERENCES
1. Ford, D. L. Factors Affecting Variability From Wastewater
Treatment Plants. Proceedings, International Conference on
Effluent Variability from Wastewater Treatment Process and Its
Control, New Orleans, December 2-4, 1974. Sponsored by the
International Association on Water Pollution Research, Tulane
University, and Vanderbilt University.
2. Carawan, R. E., W. M. Crosswhite, J. A. Macon, and B. K. Hawkings.
Water and Waste Management in Poultry Processing. EPA-660/2-74-
031. May 1974.
3. Popel, H. J. A Concept for Realistic Effluent Standards.
Proceedings, International Conference on Effluent Variability from
Wastewater Treatment Process and Its Control, New Orleans, December
2-4, 1974. Sponsored by the International Association on Water
Pollution Research, Tulane University, and Vanderbilt University.
4. Burr, I. W. Engineering Statistics and Quality Control. McGraw-
Hill Book Company, New York. 1953.
454
-------
APPENDIX
Equations Used for Calculation of Adjustment Factors for Plant 6B
Poul try
For 1977 Discharge limitations:
Rendering
BODs: (0.15 kg BODs/kkg RM) (kkg RM/kkg/LWK)
SS: (0.17 kg SS/kkg RM) (kkg RM/kkg LWK)
Further Processing
BOD
SS
D5: (0.30 kg BOD5/kkg FP) (kkg FP/kkg LWK)
: (0.35 kg SS/kkg FP) (kkg FP/kkg LWK)
For 1983 Discharge limitations:
Rendering
BOD5: (0.07 kg BOD5/kg RM) (kkg RM/kkg LWK)
SS: (0.10 kg SS/kkg RM) (kkg RM/kkg LWK)
Further Processing
BOD5: (0.15
SS: (0.18 kg SS/kkg FP) (kkg FP/kkg LWK)
BOD5: (0.15 kg BOD5/kg FP) (kkg FP/kkg LWK)
: (0.
where: RM = amount of raw materials rendered on site
FP = amount of further processing done
BOD5 (adjusted) = BOD5 (recommended for subcategory) +
BOD5 (rendering) + BOD (further processing)
SS (adjusted) = (calculate same as for BOD5)
Calculation of Probability of Sampling the Occasion of Maximum Effluent
Load
From Burr1*
C(n.r) = R(n,r)/P(r,r)
= nl/rl(n-r)
455
-------
where
C(n,r) is the desired number of combinations of n different
things r at a time,
P(n,r) is the number of permutations of n different objectives
taken r at a time, and,
P(r,r) is the number of different order in which all of r
objects may be dravm.
For the case of monthly sample, or 12 samples in 260 working days
and a violation that occurs 1 in 43 (6 in 260) working days.
C(254,6) = number of 12-sample monitoring schedule that
contain all 6 violations in a 260-day sampling period.
C(260,12) = number of 12-sample monitoring schedules in 260-
day sampling period, and
P(6 violations) = C(254,6)/C(260,12)
Where P(6 violations) is the probability of sampling the six
violations.
C(254,6) = 254:/6!(248l)
C(260,12) = 2601/121(248)!
P(6 violations) = 2.28 x 1Q-9
Similarly, for the case of weekly sampling, or 52 samples in 260
working days.
C(254,46) = 2541/461(208):
C(260,52) = 2601/521(208):
and,
P(6 violations) = 5.03 x 1Q-9
456
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REGISTRATION LIST
Jac Adams
Packer-land Packing
Company, Inc.
P. 0. Box 1184
Green Bay, WI 54305
Jim Baker
Nova Scotia Department
of Environment
P. 0. Box 2107
Halifax, Nova Scotia CANADA
Iqbal K. Bansal
Union Carbide Corporation
P. 0. Box 324
Tuxedo, NY 10987
James F. Benkovich
Hydrocyclonic Corporation
800 Skokie Highway
Lake Bluff, IL 60044
Dr. P. M. Berthouex
University of Wisconsin
3216 Engineering
Madison, WI 53706
Charles N. Best
Procon, Inc.
30 UOP Plaza
Des Plaines, IL 60016
Harold Barnett
Pacific Utilization Research
Center
2725 Montiake Boulevard, East
Seattle, WA 98112
Martha I. Beach
N-CON Systems Company, Inc.
308 Main Street
New Rochelle, NY 10801
Earl J. Benjamin
General Foods Corporation
Technical Center
555 South Broadway
Tarrytown, NY 10591
Gerald Bizjak
Becher-Hoppe Engineers, Inc.
1130 Grand Avenue
Schofield, WI 54476
Ralph S. Bosek
Lykes Brothers, Inc.
Meat Packing Division
Box 518
Plant City, FL 33566
Wayne Bough
University of Georgia
Department of Food Science
Experiment, GA 30212
457
-------
James Boydston
EPA, Pacific Northwest
Environmental Research Lab.
200 Southwest 35th Street
Corvallis, OR 97330
Mil lard Brosz
Green Giant Company
232 Regency Road
LeSueur, MN 56058
Shyrl Bucholz
Libby, McNeil and Libby
1800 West 119th Street
Chicago, IL 60643
Max Cochrane
EPA, Pacific Northwest
Environmental Research Lab.
200 Southwest 35th Street
Corvallis, OR 97330
George Coulman
Michigan State University
Department of Chemical
Engineering
East Lansing, MI 48824
Dr. Samun Dahodwala
Calor Agriculture Research
2367 Science Parkway
Okemos, MI 48864
Dr. N. Ross Bui ley
University of British
Columbia
2075 Wesbrook Place
Vancouver, BC CANADA V6T 1W5
Donald Bzdyl
Westinghouse-Aquatechnics
1010 Jorie Boulevard
Oak Brook, IL 60521
Satyendra M. De
Chestnut Operating Company
2nd and Chestnut Streets
Reading, PA 19602
Charles Decker
Jacobs Engineering Company
22 West Madison Street
Chicago, IL 60602
Roy E. Carawan
North Carolina State
University
Schaur Hall
Raleigh, NC 27607
Paul Chapman, PhD
The Pillsbury Company
311 2nd Street, Southeast
Minneapolis, MN 55414
Frank Deitch
Libby, McNeil and Libby
200 South Michigan Avenue
Chicago, IL 60604
Donald 0. Dencker
Oscar Meyer and Company
P. 0. Box 1409
Madison, WI 53701
Jim Chittenden
Iowa Beef Processors
P. 0. Box 151
Dakota City, NE 68731
Marshal Dick
EPA, Office of Research and
Development
Waterside Mall West
Washington, DC 20460
458
-------
Jess C. Dietz
Clark, Dietz and Associates
211 North Race Street
Urbana, IL 61801
George Evans
Consulting Engineer
P. 0. Box 24
Harrison, NY 10528
James N. Dornbush
South Dakota State University
Civil Engineering Department
Brookings, SD 57006
Giles Farmer
W. L. Clayton Research Centc
3333 North Central Expresswe
Richardson, TX 75080
Kenneth A. Dostal
EPA, Pacific Northwest
Environmental Research Lab.
200 Southwest 35th Street
Con/all is, OR 97330
A. W. Dutcher
Mammoth Spring Corporation
P. 0. Box A
Sussex, WI 53089
Lawrence Feder
Roy F. Weston, Inc.
3201 Old Glenview Road
Wilmette, IL 60091
Edward Fernback
Trotter-Yoder and Associate;
2085 North Broadway
Walnut Creek, CA 94596
Mrs. Maurene Ehlers
Western Polymer Corporation
P. 0. Box 488
Tulelake, CA 96134
Lawrence Field
Eimco-Envirotech
301 South Hicks Road
Palatine, IL 60067
Thomas Elliott
Swift Fresh Meats Company
115 West Jackson Boulevard
Chicago, IL 60604
Gary Flann
EPCO-Hormel
P. 0. Box 800
Austin, MN 55912
D. E. Erickson
North Star Division
Midwest Research Institute
3100 38th Avenue, South
Minneapolis, MN 55406
Larry Esvelt
Bevoy Engineers
808E Sprague Avenue
Spokane, WA 99202
Gary Flickinger
Dean Foods
1126 North Kilburn
Rockford, IL 61108
Dr. Kendall Foley
Hercules, Inc.
Research Center
Wilmington, DE 19899
459
-------
Mel Freeman
Northwestern Power
Equipment Company
1951 University
Saint Paul, MN 55104
Dr. R. X. Gallop
University of Manitoba
Fort Garry, Winnipeg, R3T 2N2
Manitoba, CANADA
Alex Grinkevich
Hunt-Wessen
1645 West Valencia Drive
Fullerton, CA 92670
David L. Grothman
Oscar Meyer and Company
910 Mayer Avenue
Madison, WI 53701
James D. Gallup
EPA, Effluent Guidelines
Division
Waterside Mall East
Washington, DC 20460
Ms. Teri Garin
General Foods Corporation
250 North Street
White Plains, NY 10625
R. E. Gerhard
G. A. Hormel and Company
P. 0. Box 800
Austin, MN 55912
Michael Glagola
Union Carbide
26500 North Western Highway
Southfield, MI 48076
David A. Gubser
Star-Kist Foods, Inc.
582 Tuna Street
Terminal Island, CA 90731
Dr. C. Fred Gurnham
Gurnham and Associates, Inc.
223 West Jackson Boulevard,
Room 600
Chicago, IL 60606
Marc Hanson
Wisconsin Department of
Natural Resources
P. 0. Box 450
Madison, WI 53701
Dr. W. J. Harper
Ohio State University
2121 Fyffe Road
Columbus, OH 43210
James Grant
204 Lake Shore Drive
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Research Microbiologist
4615 Harvard Road
College Park, MD 20740
Thomas Harpt
Wisconsin Department of
Natural Resources
P. 0. Box 450
Madison, WI 53701
Robert D. Harriger
Allied Chemical Corporation
P. 0. Box 6
Solvax, WY 13209
460
-------
R. 6. Herrick
Del Monte Corporation,
Midwest Division
P. 0. Box 89
Rochelle, IL 61068
Harrison Hi tenner
Wisconsin Department of
Natural Resources
P. 0. Box 450
Madison, UI 53701
Roger Huibregtse
The Larsen Company
520 North Broadway
Green Bay, WI 54301
Robert Hyner
Bio-Surf Division
Autotrol Corporation
5855 North Glen Park Road
Milwaukee, WI 53209
Michael Jamiolkowski
Stokely-Van Camp, Inc.
6815 East 34th Street
Indianapolis, IN 46226
Dennis Johnson
Swift Fresh Meats Company
115 West Jackson Boulevard
Chicago, IL 60604
Mike E. Joyce
EPA, Pacific Northwest
Environmental Research Lab.
200 South 35th Street
Corvallis, OR 97330
Arthur B. Kaplan
Badger Laboratories and
Engineers
P. 0. Box 363
Appleton, WI 54911
Joan Karnauskas
Wisconsin Department of
Natural Resources
P. 0. Box 450
Madison, WI 53701
Gaden T. Kaskey
Magnusen Engineers, Inc.
1010 Timothy Drive
San Jose, CA 95133
Robert Jaost
Environmental Dynamics
P. 0. Box 675
Oconomowoc, WI 53066
Allen M. Katsuyama
National Canners Association
1950 6th Street
Berkeley, CA 94710
N. A. Jaworski
EPA, Pacific Northwest
Environmental Research Lab.
200 South 35th Street
Corvallis, OR 97330
William Jewell
Cornell University
202 Riley-Robb Hall
Ithaca, NY 14853
Donald Kirk
Heinz USA
P. 0. Box 57
Pittsburgh, PA
15230
Vaclav Kresta
New Brunswick Department
of Environment
Centennial Building
Fredericton, CANADA New Brunswick
461
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Les Lash
EIMCO BSP Division of
Envirotech Corporation
P. 0. Box 300
Salt Lake City, UT 84110
Paul Leavitt
Gerber Products"Company
445 State Street
Fremont, MI 49412
James 0. McDonald
EPA, Region IV
230 South Dearborn
Chicago, IL 60626
Jim McFarland
Hemco, Inc.
P. 0. Box 37203
Omaha, NB 68137
George Lindsay
Environment Canada
P. 0. Box 2406, Halifax
Nova Scotia, CANADA B3J 3E4
L. Lively
John Morrell and Company
208 South LaSalle
Chicago, IL 60604
Jack McVaugh
Envirex, Inc.
Box 1067
1901 South Prairie Avenue
Waukesha, WI 53186
Reginald E. Meade
The Pillsbury Company
311 2nd Street, Southeast
Minneapolis, MN 55414
Dennis Lonergan
Wisconsin Department of
Natural Resources
P. 0. Box 450
Madison, WI 53701
Daryl Lund
Department of Food Science
University of Wisconsin
Madison, WI 53706
Bruce E. Meyer
Westinghouse-Aquatechnics
1010 Jorie Boulevard
Oakbrook, IL 60521
Donald S. Murnberg
Mark, Dietz and Associates
200 East Ontario
Chicago, IL 60611
Marvin Marmorine
Green Giant Company
232 Regency Road
LeSuer, MN 56058
Jerry Nelson
Okray Ltd,
3000 Welsby Avenue
Stevens Point, WI 54481
Alton McCully
Agripac, Inc.
799 Ferry
Eugene, OR 97401
S. T. Oliver
THEHEIL Company
3000 West Montana Street
Milwaukee, WI 53201
462
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Francis D. Osborn
Rleke Carroll Muller
Associates, Inc.
P. 0. Box 130
Hopkins, MN 55343
Warren G. Palmer
FMC Corporation
1185 Coleman Avenue, Box 580
Santa Clara, CA 95052
Alvin H. Randall
Wisconsin Canners and
Freezers Association
110 East Main Street
Madison, WI 53703
Larry Read
Zenk Engineering Corporation
1206 West Front Street, Box 689
Albert Lea, MN 56007
Don Pavlat
Packer!and Packing Company, Inc.
P. 0. Box 1184
Green Bay, WI 54305
L. Petrovic
Mammoth Spring Corporation
P. 0. Box A
Sussex, WI 53089
Victor F. Pietrucha
Airco Industrial Gases
575 Mountain Avenue
Murray Hill, NJ 07974
James Richie
EPCO Division
George A. Hormel and Company
Box 800
Austin, MN 55912
M. J. Riddle
Environment Canada
351 Saint Joseph Boulevard
Ottawa, Ontario K1A OH3
CANADA
James R. Robinson
Stokely-Van Camp, Inc.
6815 East 34th Street
Indianapolis, IN 46226
Lawrence Polkowski
University of Wisconsin
3204 Engineering Building
Madison, WI 53706
Anthony Poulos
Libby, McNeil! and Libby
5555 West 115th
Worth, IL 60482
Jerry Rodenberg
Wisconsin Department of
Natural Resources
P. 0. Box 450
Madison, WI 53701
Walter W. Rose
National Canners Association
1950 6th Street
Berkeley, CA 94710
William Priebe
Frito-Lay, Inc.
900 North Loop 12
Irving, TX 75060
Robert Roskopf
Rieke Carroll Muller
Associates, Inc.
P. 0. Box 130
Hopkins, MN 55343
463
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James Santroch
EPA, Pacific Northwest
Environmental Research Lab.
200 Southwest 35th Street
Corvallis, OR 97330
James F. Scaief
EPA, Pacific Northwest
Environmental Research Lab.
200 Southwest 35th Street
Con/all is, OR 97330
Kenneth F. Schessler
Libby, McNeil and Libby
147 North Rural Street
Hartford, WI 53027
Edward A. Smith
Cantadina Foods
Caranation Company
2906 Santa Fe
Riverbank, CA 95367
Traver J. Smith
Magnuson Engineers, Inc.
P. 0. Box 5846
San Jose, CA 95150
Clarence G. Sprague
Green Giant Company
232 Regency Road
LeSuer, MN 56058
Curt Schmidt
SCS Engineers
4014 Long Beach Boulevard
Long Beach, CA 90807
Patrick M. Stanley
Safeway Stores, Inc.
425 Madison Street
Oakland, CA 94660
John Schultz
Wisconsin Department of
Natural Resources
P. 0. Box 450
Madison, WI 53701
William Schultz
USDA, Western Regional
Research Center
800 Buchanan Street
Albany, CA 94710
David Schwerbel
Wisconsin Department of
Natural Resources
P. 0. Box 450
Madison, WI 53701
Larry Scully
University of Wisconsin
1341 South Street1
Madison, WI 53706
P. Vincent Stephenson
01 in Water Services
3155 Fiberglas Road
Kansas City, KS 66115
Richard W. Sternberg
Clayton Environmental
Consultants
25711 Southfield Road
Southfield, MI 48075
Charles Stevenson
Curtice-Burns, Inc.
P. 0. Box 670
Rochester, NY 14602
Herbert E. Stone
Del Monte Corporation
P. 0. Boc 3575
San Francisco, CA 94119
464
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Ronald J. Streeter
Wilson and Company, Inc.
4545 Lincoln Boulevard
Oklahoma City, OK 73105
Thomas G. Walsh
Libby, McNeil and Libby
200 South Michigan Avenue
Chicago, IL 60604
Edmund J. Struzeski, Jr.
National Field Investigations
Center - Denver Federal Center
P. 0. Box 25227, Building 53
Denver, CO 80225
Ir P. Ten Have
Government Agricultural
Wastewater Service
Rijks Agrarische Afvalwaterdienst
Kemperbergerweg 11, HOLLAND
Harold W. Thompson
EPA, Pacific Northwest
Environmental Research Lab.
200 Southwest 35th Street
Corvallis, OR 97330
Donald J. Thornsin
General Mills, Inc
9000 Plymouth Avenue, North
Minneapolis, MN 55427
Desmond B. Watt
Westinghouse-Aquatechnics
1010 Josie Boulevard
Oak Brook, IL 60521
Richard T. Webb
Hilo Coast Processing Company
P. 0. Box 18
Pepeekeo, HI 96783
K. G. Wecker
University of Wisconsin
Department of Food Science
Madison, WI 53706
Jerome Weinberg
The All bright-Nell Company
5323 South Western Boulevard
Chicago, IL 60609
Jon F. Tienstra
Allen Products Company,
Rural Delivery #3
Allentown, PA 18001
Inc.
Paula B. Wells
Bell-Galyardt-Wells
5634 South 65th Street
Omaha, NE 68127
Clavin R. Tininenko
Farmland Foods, Inc.
10700 West Waveland
Franklin Park, IL 60131
W. James Wells, Jr.
Bell-Galyardt-Wells
5634 South 85th Street
Omaha, NE 68127
William Trygstad
Zenk Engineering, Inc.
1206 West Front Street, Box 689
Albert Lea, MN 56007
Maurice A. Williams
Anderson IBEC
19699 Progress Drive
Strongville, OH 44136
465
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Jack L. Witherow Walter S. Young, Jr.
EPA, Pacific Northwest Union Carbide Corporation
Environmental Research Lab. P. 0. Box 65
200 Southwest 15th Street Tarrytown, NY 10591
Corvallis, OR 97330
Hoya Y. Yang Lee Zach
Department of Food Science The Rath Packing Company
and Technology P. 0. Box 330
Oregon State University Water!ou, IA 50704
Con/all is, OR 97331
466
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TECHNICAL REPOnT DATA
(riease read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-76-224
2.
3. RECIPIENT'S ACCESSION1 NO.
4. TITLE AND SUBTITLE
PROCEEDINGS OF THE SIXTH NATIONAL SYMPOSIUM ON FOOD
PROCESSING WASTES
5. REPORT DATE
December 1976 (Issuing Date)
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT-NO.
9 PERFORMING ORGANIZATION NAME AND ADDRESS ~ "
Industrial Pollution Control Division- Cin., OH
Industrial Environmental Research Laboratory
US Environmental Protection Agency
Cincinnati, Ohio 45268
10. PROGRAM ELEMENT NO.
1BB037
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
National Canners Association, Berkeley, Calif. 94710;
Wisconsin Canners and Freezers Association, Madison ;
U.S. Environmental Protection Agency, Cincinnati,
Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA/600/12
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The Sixth National Symposium on Food Processing Wastes was co-sponsored with
the National Canners Association and the Wisconsin Canners and Freezers Association.
The primary purpose of these symposia is the dissemination of the latest
research, development and demonstration information on process modifications, waste
treatment by-product recovery and water reuse to industry, consultants, and
government personnel. Twenty papers are included in this Proceedings as well as the
final registration list.
These symposia will be continued; the Seventh is scheduled for April 7-9, 1976,
in Atlanta, Georgia. If you are interested in participating or wish to receive
additional information contact:
Industrial Pollution Control Division
Industrial Environmental Research Laboratory
US Environmental Protection Agency
Cincinnati, Ohio 45268
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
*Industrial Wastes, *Food Processing,
*Food Industry, *Treatment, Byproducts
Food Processing Industry
Byproduct Recovery,
Process Modification,
Food Processing Waste
Characterization, Food
Processing Waste
Treatment
13/B
8. DISTRIBUTION STATEMENT
UNLIMITED
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
475
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
467
* U.S. GOVERNMENT PRINTING OFFICE 1977-7 57 -056 / 549Z
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