United States
Environmental Protection
Agency
Industrial Environmental Research EPA-600/2-78-188
Laboratory August 1978
Cincinnati OH 45268
Research and Development
Proceedings
Ninth National
Symposium
on Food Processing
Wastes
March 29-31, 1978
Denver, Colorado
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1 Environmental Health Effects Research
2 Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5 Socioeconomic Environmental Studies
6 Scientific and Technical Assessment Reports (STAR)
7 Interagency Energy-Environment Research and Development
8 "Special' Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service Springfield, Virginia 22161.
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EPA-600/2-78-188
August 1978
PROCEEDINGS NINTH NATIONAL SYMPOSIUM
ON FOOD PROCESSING WASTES
March 29 - 31, 1978
Denver, Colorado
by
Food and Wood Products Branch
Industrial Environmental Research Laboratory
Corvallis, Oregon 97330
Co-sponsored by
National Food Processors Association
American Meat Institute
Southeastern Poultry and Egg Association
Western States Meat Packers Association
Pacific Egg and Poultry Association
American Society of Agricultural Engineers
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
This report has been reviewed by the Industrial Environmental Research
Laboratory-Cincinnati, U.S. Environmental Protection Agency, and approved
for publication. Approval does not signify that the contents necessarily
reflect the views and policies of the U.S. Environmental Protection Agency
nor does mention of trade names or commercial products constitute endorse-
ment or recommendation for use.
11
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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 con-
trol methods by used. The Industrial Environmental Research Laboratory-Cin-
cinnati (lERL-Ci) assists in developing and demonstrating new and improved
methodologies that will meet these needs both efficiently and economically.
The Ninth National Symposium on Food Processing Wastes was co-sponsored
with the National Food Prodessors Association, American Meat Institute,
Southeastern Poultry and Egg Association, Western States Meat Packers
Association, Pacific Egg and Poultry Association and the American Society
of Agricultural Engineets. The primary purpose of these symposia is the
dissemination of the latest research, development, and demonstration infor-
mation of process modifications waste treatment, by-product recovery and
water reuse to industry, consultants and government personnel. Twenty-
four papers are included in this Proceedings as well as the final registra-
tion list. For more information contact the Food and Wood Products Branch
of the Industrial Pollution Control Division.
David G. Stephan
Director
Industrial Environmental Research Laboratory
Cincinnati
111
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ABSTRACT
The Proceedings contains copies of the 24 papers presented at the
Ninth National Symposium on Food Processing Wastes. Subjects included:
processing modifications product and by-product recovery, wastewater treat-
ment, water recycle and water reuse for several segments of the food pro-
cessing industry. These segments included: red meat and poultry, seafood,
dairy, fruit, and vegetable.
Attendance at the two and one-half day Symposium was approximately
170 with good representation by industry, universities, consulting firms,
as well as state and Federal agencies.
iv
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CONTENTS
Foreword iii
Abstract iv
A SUMMARY OF COLD CLIMATE OPERATING EXPERIENCES WITH
BIOLOGICAL WASTE TREATMENT SYSTEMS IN THE FOOD PROCESSING
INDUSTRY
C. W. Fulton, P. A. Mulyk, J. Haskill 1
THE UTILIZATION OF CHEESE WHEY FOR WINE PRODUCTION
G. M. Palmer, R. F. Marquardt 61
TREATMENT OF CAUSTIC PIMIENTO WASTEWATER
T. M. Furlow, P. Chen 68
OVERLAND FLOW TREATMENT OF DUCK PROCESSING WASTEWATER
IN A COLD CLIMATE
L. H. Ketchum, Jr 77
ECONOMICS OF STARCH AND ANIMAL FEED PRODUCTION FROM CULL POTATOES
J. R. Rosenau, L. F. Whitney, J. R. Haight 89
NITROGEN FIXING BIOMASS FOR AEROBIC TREATMENT OF SOFT DRINK
BOTTLING PLANT WASTEWATER
P. Y. Yang, I. S. Ting 100
TREATING TROUT PROCESSING WASTEWATER--A SUCCESSFUL CASE HISTORY
J. S. Keith 110
RECIRCULATION OF CONTAINER COOLING WATER AS A MEANS OF WATER
CONSERVATION IN FOOD PROCESSING PLANTS 118
N. L. Jacob
LOW BOD RECIRCULATION STEAM BLANCHING
D. R. MacGregor, P. Parchomchuk 136
LAND VS. ACTIVATED SLUDGE TREATMENT OF POTATO PROCESSING
WASTEWATER
K. L. Sirrine 142
A DESIGN PROCEDURE FOR LAND APPLICATION
E. J. Kroeker, A. Lamb, J. M. Haskill 149
v
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USING MICROWAVES TO REDUCE POLLUTION FROM SCALDING CHICKENS
B. F. Miller, S. A. Kula, J. W. Goble, H. L. Enos 173
ACTIVATED SLUDGE TREATMENT OF WASTEWATERS FROM THE DAIRY PRODUCTS
INDUSTRY
P. H. M. Guo, P. J. Fowlie, B. E. Jank 178
TREATMENT OF BIRD CHILLER WATER FOR REUSE IN PLUMING BROILER
GIBLETS
H. S. Lillard 203
DESIGN AND OPERATION OF A VEGETABLE OIL PLANT WASTEWATER
TREATMENT SYSTEM FOR FUTURE STANDARDS
N. J. Smallwood 213
DISSOLVED AIR FLOTATION TREATMENT OF GULF SHRIMP CANNERY
WASTEWATER
A. J. Szabo, L. F. LaFleur, F. R. Wilson 221
UPGRADING A BREWERY WASTEWATER PRETREATMENT FACILITY FOR THE
CITY OF WINSTON-SALEM
C. C. Malone, R. M. Stein, T. D. Cornett 231
PHOSPHORUS REMOVAL AND DISINFECTION OF MEAT PACKING LAGOON
EFFLUENT
R. T. Beaupre, M. D. Redick 247
PHYSIOCHEMICAL TREATMENT OF RENDERING WASTEWATER BY ELECTRO-
COAGULATION
E. R. Ramirez, 0. A. Clemens 265
PROTEIN RECOVERY FROM MEAT PACKING EFFLUENT
D. E. Hallmark, J. C. Ward, H. C. Isaksen, W. Adams 288
A METHOD OF PHYSICO-CHEMICAL TREATMENT OF ORGANIC
WASTEWATERS
P. Stephenson 306
WASTEWATER TREATMENT AND REUSE IN AN INDEPENDENT RENDERING COMPANY
W. R. Isherwood, J. McVaugh 321
THE IMPACT OF THE CLEAN WATER ACT OF 1977 ON THE FOOD
PROCESSING INDUSTRY
C. Schafer 336
THE APPLICATION OF DEEP SHAFT TECHNOLOGY TO THE TREATMENT
OF FOOD PROCESSING WASTEWATER
D. S. Sandford, P. Eng, T. Gallo 341
REGISTRATION LIST 359
VI
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A SUMMARY OF COLD CLIMATE OPERATING EXPERIENCES
WITH BIOLOGICAL WASTE TREATMENT SYSTEMS
IN THE
FOOD PROCESSING INDUSTRY
by
C. W. Fulton*, P. A. Mulyk*, and J. Haskill**
INTRODUCTION
Food processing operations are a source of highly concentrated organic
wastewater which is amenable to stabilization by biological treatment.
A wide variety of biological processes are available and have been
employed by the Industry in an attempt to provide the necessary treatment.
While many treatment systems have been very successful, others have
encountered severe operating problems and performance has not always met
Industry's and regulatory agencies' expectations. This, has been particularly
true in northern regions, where cold climates impose an additional
hardship on the operation of biological systems.
As part of a project conducted for the Food and Allied Industries,
Abatement and Compliance Branch of the Water Pollution Control Directorate
of Fisheries and Environment Canada, Stanley Associates Engineering Ltd.
conducted site visits to a number of food processing plants in Canada
and the northern United States. The objective of these visits was to
obtain operating and performance data on biological waste treatment
systems utilized by the Industry, and to discuss the problems being
encountered in their operation.
Plant visits were restricted to those facilities which were considered
by local or Federal regulatory agencies to exemplify best practicable
technology for the Industry.
This paper presents case histories of twelve such plants, outlining
their design criteria, loading rates, treatment efficiencies, operating
experience, and capital and operating costs. The case histories presented
cover the sectors of the food processing industry outlined below:
-'Stanley Associates Engineering Ltd., Calgary, Alberta
**Food and Allied Industries, Water Pollution Control Directorate,
Fisheries and Environment Canada, Ottawa, Ontario
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1) Meat and Poultry Processing: 2 poultry plants
3 red meat plants
2) Dairy and Milk Processing: 3 plants
3) Fruit and Vegetable Processing: 1 potato plant
1 fruit juice plant
4) Beverage Industry: 1 distillery
5) Fish Processing: 1 plant.
COST DATA
Difficulty was encountered in gathering reliable information on capital
and operating costs for the majority of plants visited. In some cases,
the information simply did not exist. Where data on the capital cost of
treatment facilities was provided, this has been updated to a November
1977 value, using an Engineering News Record Construction Cost Index of
2660.
Where possible, actual operating costs reported by the plants have been
presented. However, in the majority of cases, such data did not exist.
As a result, operating costs for these plants have been estimated on the
basis of the manpower and electrical requirements of the facility, as
reported by plant personnel. A standard value of $10/hour for manpower
costs and 2.5c/kW-hr for electrical power has been used in calculating
operating costs, and to facilitate comparisons between plants. The
manpower cost is based on the average 1977 wage rate in the Canadian
construction industry, while the energy cost represents the average
electric power cost at municipal sewage treatment plants in Alberta in
1977.
The total annual costs presented include the annual operating cost plus
an 11% annual amortization allowance on capital cost (10% interest rate;
25 year amortization period). Unit treatment costs (i.e. cost per m of
wastewater treated and cost per kilogram of BOD removed) are based on
the total annual cost and quantity of wastewater treated annually.
MEAT AND POULTRY PLANTS
Plant A
Plant A is a poultry processing operation that slaughters approximately
18,000 birds/day on an 8 hr/day, 5 day/week basis.
An extended aeration plant with integral clarifier, as shown in Figure 1,
was installed in 1972 to treat an average wastewater flow of 455 m-Vday
(100,000 Igpd). As illustrated in Figure 2 the waste treatment facilities
include screening of the raw wastewater, aeration, clarification and
physical/chemical treatment of the clarifier effluent.
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FEED
INLET
AERATION
BASIN
MECHANICAL
SURFACE
AERATOR
LUD6E RETURN TO
AERATION BASIN
CLARIFIER
EFFLUENT
WEIRS
OUTLET
CLARIFIER
SLUDGE
BLANKET
SLUDGE
SCRAPING
MECHANISM
SECTION A-A
FIGURE 1 - AERATION BASIN
WITH INTEGRAL CLARIFIER
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PLANT A
PROCESS
EFFLUENT
LAGOON SUPERNATANT
WASTE SLUDGE
VIBRATING
SCREEN
AERATION BASIN
WITH INTEGRAL
CLARIFIER
SLUDGE
STORAGE
LAGOON
SECONDARY
EFFLUENT
DISCHARGE
TO
CREEK
CHLORINATION
CHEMICAL
ADDITION
FIGURE 2 - Schematic Flow Sheet of Waste Treatment Plant
(Plant A)
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The operating and design criteria for the extended aeration plant are
summarized in Table 1.
Current wastewater flow rates average approximately 318 m /day (70,000
Igpd) and the process is generally achieving BOD- and suspended solids
removals of greater than 95% and 90% respectively. Clarifier effluent
BOD concentrations are less than 30 mg/L and suspended solids concentrations
are less than 40 mg/L.
The wasting of biological sludge is practiced very infrequently. When
carried out, sludge is discharged to an abandoned 3 stage lagoon system
on the plant property. Supernatant from the lagoon is returned to the
aeration basin during periods of low flow.
Shortly after start-up, a problem of turbulence in the integral secondary
clarifier was encountered. This was apparently solved by adding anti-
rotational baffles to three sides of the aeration basin.
Freezing problems were also encountered with the integral clarifier,
although these were alleviated by enclosing the clarifier in a metal
structure, and blowing warm air over the liquid surface.
The waste treatment facility is operated and maintained on a part-shift
basis by one man, who is also responsible for maintenance of the plant's
boiler room.
Construction of the plant was completed in April 1972 at a cost of
approximately $257,000 (including tertiary physical/chemical treatment).
Using the ENR construction cost index for updating purposes, this corresponds
to a November 1977 cost of approximately $400,000 as shown in Table 2.
Annual operating and maintenance costs for the extended aeration phase
of the treatment process are estimated at approximately $18,600.
Plant B
Plant B is a poultry operation that slaughters and processes approximately
38,000 birds/8 hour-day, 5 days per week. All blood, feathers, offal,
and dead-on-arrival and contaminated birds are recovered and sent to an
on-site rendering facility.
Grease is recovered from the process wastewater for rendering by means
of air flotation prior to discharge to a wet-well. The wastewater from
the wet-well is then pumped to 4 vibrating screens. The screened waste
flows through a splitter box to an extended aeration plant, which is in
turn followed by a facultative lagoon, as shown in Figure 3.
The extended aeration plant consists of two earthen aeration basins
operated in parallel. These cells are interconnected to permit series
operation, if so desired. Overflow from the aeration cells enters a
secondary clarifier and sludge removed from the clarifier bottom is
recycled to the splitter box.
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TABLE 1 - OPERATING AND DESIGN CRITERIA FOR
EXTENDED AERATION PROCESS (PLANT A)
Wastewater Characteristics:
Flow: Average: 318 m /day (70,000 Igpd) - 5 days/week
3
Design: 455 m /day (100,000 Igpd) - 5 days/week
BOD :
Range:
Average:
400 - 900 mg/L
600 mg/L
SS:
Range:
Average:
250 - 500 mg/L
400 mg/L
Organic Loading Rate:
0.05 kg BOD5/kg MLSS/day
Volumetric Loading Rate
240 g BOD /day/m
(15 Ib BOD 71,000 ft3/day)
MLSS Concentration:
4,000 - 5,000 mg/L
Detention Time:
3 days
Aeration Requirements:
19 kW - Mechanical Surface Aerator
3
(14 kW/1000 m of basin volume)
Secondary Clarifier
Overflow Rate:
19.5 m3/day/m2
(400 Igpd/ft2)
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TABLE 2 - CAPITAL AND OPERATING COSTS FOR THE
EXTENDED AERATION PROCESS (PLANT A)
Capital Cost (adjusted to 1977) $400,000
Annual Amortized Capital Cost @ 11% $44,000
Operating Costs:
Manpower: 1040 hr/yr @ $10/hr $10,400
Electrical Power:
327,000 kW-hr/yr x $0.025/kW-hr $ 8,200
Annual Operating Cost $18,600
Total Annual Cost $62,600
3
Cost per m Treated $0.75
($3.40/1000 I.G.)
Cost per kg BOD Removed $1.32
($0.60/lb)
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CHLORINATION
BASIN
PLANT
B
oo
AIR FLOTATION
TANK
VIBRATING
SCREENS
DISCHARGE
TO
CREEK
POLISHING
POND
FIGURE 3 - Schematic Flow Sheet of Haste Treatment Process
(Plant B)
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Clarifier effluent flows to a 1.6 hectare (4 acre) polishing pond and
effluent from the pond is chlorinated prior to discharge to a small
receiving stream.
The operating and design criteria for the extended aeration plant and
lagoon are summarized in Table 3.
3
Current wastewater flow rates average approximately 1900 m /day (425,000
Igpd). Effluent from the secondary clarifier contains less than 30 mg/L
BODij and 75 mg/L suspended solids, although this is further reduced to
approximately 10 mg/L BODj. and 15 mg/L suspended solids in the polishing
pond. Overall BOD^ and suspended solids removals are 98% and 97%,
respectively.
Some problems have been encountered with the loss of biological solids
from the secondary clarifier. This has been attributed to sludge
bulking, and to flow surges which result in increased overflow rates in
the clarifier. Chlorination of return sludge to control filamentous
organism growth and reduce bulking has been conducted on'an experimental
basis but results were inconclusive. It is believed that flow equalization
would help alleviate the problem, but equipment and facilities are not
available to test this.
The presence of high concentrations of algae in the polishing lagoon in
summer months imparts a green colour to the final effluent. For this
reason, the polishing pond has been by-passed for short periods during
the summer to prevent the discharge of aesthetically unacceptable
effluent.
Winter operation has resulted in some icing problems, particularly with
the rotating skimmer arm of the secondary clarifier. This has necessitated
removal of the arm in fall to facilitate winter operation. In addition,
it has been found necessary to chip ice from the umbrella which forms
around the two surface aerators.
Sludge wasting has not been necessary for the past two years, however
when carried out, the sludge is trucked to a landfill site.
The waste treatment plant is operated by one man on a full-time basis.
Capital and operating costs for the treatment plant are presented in
Table 4. The plant was constructed in 1972 at a cost of approximately
$500,000 (excluding land), which corresponds to a November 1977 cost of
approximately $780,000, based on the ENR construction cost index.
Annual operating and maintenance costs are estimated at $50,800.
Plant C
Plant C is a hog processing and rendering operation, slaughtering approximately
4,000 hogs/day on an eight hour/day, five day/week basis.
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TABLE 3 - OPERATING AND DESIGN CRITERIA FOR EXTENDED
AERATION/POLISHING LAGOON PROCESS (PLANT B)
Wastewater Characteristics:
Flow - Average: 1900 m /day (425,000 Igpd) - 5 days/week
(Average Flow during 8 hour processing period is
approximately 38 L/sec)
(Overnight and Weekend Flow is approximately 11 L/sec)
BOD :
Range: 300 - 2,000 mg/L
Average: 800 mg/L
SS:
Range: 300 - 1,000 mg/L
Average: 500 mg/L
Extended Aeration System:
Organic Loading Rate: 0.02 - 0.05 kg BOD /kg MLSS/day
Volumetric Loading Rate: 160 - 320 g BOD /day/m
(10 - 20 Ib BOD5/1,000 ft3/day)
MLSS Concentration:
3800 - 5200 mg/L
Detention Time:
5.5 days
Aeration Requirements:
2 Mechanical Surface Aerators - 1 @ 56 kW
and 1 @ 75 kW
(12 kW/1000 m of basin volume)
Secondary Clarifier:
Polishing Lagoon:
Organic Loading Rate:
Depth:
Overflow Rate -
19.5 m3/day/m2
(400 Igpd/ft2)
at 26 L/s (350 Igpm)
2.2 g/day/m
(20 Ib BOD /acre/day)
1.8 m
(6 ft)
10
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TABLE 4 - CAPITAL AND OPEPATING COSTS OF
EXTENDED AERATION/POLISHING
LAGOON PROCESS (PLANT B)
Capital Cost (adjusted to 1977) $780,000
Annual Amortized Capital Cost @ 11% . t $85,000
Operating Costs:
Manpower: 2080 hr/yr @ $10/hr . . , , . T $20,800
Electrical Power: 118,000 kW-hr/yr x $0.025/kW-hr . . $30,000
Annual Operating Cost $50,800
Total Annual Cost $135,000
Cost per m Treated $0.26
($1.20/1000 I.G.)
Cost per kg BOD Removed $0.33
($0.15/lb)
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The wastewater treatment facility is comprised of an extended aeration
process preceded by anaerobic lagoons. The raw waste is screened, and
passed through an air flotation unit for removal of solids, fats, and
grease. It then flows to a splitter box, where it can be diverted to
either or both of two anaerobic lagoons operated in parallel (only one
anaerobic lagoon is in use at present). Effluent from the lagoons
enters a common aeration basin from which it is discharged to a secondary
clarifier. Clarifier overflow is then chlorinated and either discharged
directly to a nearby river, or stored in a holding pond if the effluent
quality is unacceptable. Sludge from the secondary clarifier is returned
to the aeration tank to maintain an MLSS concentration of approximately
5,000 mg/L. Excess sludge is wasted to the anaerobic lagoons for digestion,
thereby eliminating any sludge handling problems.
A schematic flow diagram of the treatment process is illustrated in
Figure 4. Operating and design criteria for the treatment plant are
summarized in Table 5.
Winter wastewater temperatures have necessitated construction of a
prefabricated building over the final clarifier to reduce icing problems.
Mechanical failure of the aerator vanes, due to ice build-up, has also
been encountered.
The use of the holding pond for effluent polishing in cold weather has
been found beneficial in maintaining a high quality effluent on a year-
round basis.
The plant is maintained by a trained operator on a full-time (8 hr/day,
5 day/week) basis. The operator monitors influent and effluent quality,
sludge settleability, MLSS concentration and dissolved oxygen on a daily
or weekly basis, depending upon the stability of the process performance.
Close monitoring of the process has revealed that significant power
savings can be realized, without impairing treatment performance, by
operating two aerators continuously and two only 50% of the time.
Since its construction in 1975, the plant has been producing a final
effluent with less than 30 mg/L BOD and suspended solids. The anaerobic
lagoon has achieved approximately 60% removal of BOD and 50% of suspended
solids. Overall treatment efficiency is approximately 98% for BOD,.
removal and 96% for suspended solids.
No data is available on the construction cost of the plant, but operating
costs are estimated at approximately $49,000 annually as shown in Table 6.
Plant D
Plant D is a small slaughtering and meat packing facility. Beef, pork
and lamb are processed at an average rate of approximately 9,000 kg
(20,000 Ibs) LWK/day on an 8 hour/day, 5 day/week basis.
12
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PLANT C
SCREEN
AIR
FLOTATION
TANK
WASTE SLUDGE
1
ANAEROBIC
LAGOON
NO. 1
ANAEROBIC
LAGOON
NO. 2
I
SLUDGE & ,SCUM PIT
O
HOLDING POND
DISCHARGE TO
RIVER
FIGURE 4 - Schematic Flow Sheet of Waste Treatment Process
(Plant C)
13
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TABLE 5 - OPERATING AND DESIGN CRITERIA FOR ANAEROBIC
LAGOON/EXTENDED AERATION PROCESS (PLANT C)
Wastewater Characteristics:
Flow - Average: 1820 m3/day (400,000 Igpd)
Peak: 3410 m3/day (750,000 Igpd)
Design: 5,000 m3/day (1,100,000 Igpd)
BOD5: Range: 700 - 2,000 mg/L
Average: 1500 mg/L
SS: Range: 400 - 1,200 mg/L
Average: 800 mg/L
Anaerobic Lagoon (under present average flow conditions - i.e. only one
lagoon in operation)
3
Organic Loading Rate: 270 g BOD /day/m
(17 Ib BOD5/1,000 ft3/day)
Depth: 4.6 m (15 ft)
Detention Time: 7.3 days
Extended Aeration (under present average flow conditions):
Organic Loading Rate: <0.04 kg BOD /kg MLSS/day
3
Volumetric Loading Rate: <176 g BOD /day/m
(11 Ib BOD /I,000 ft3/day)
MLSS Concentration: 5,000 mg/L
Detention Time: 2.8 days
Aeration Requirements: 4 Mechanical Surface Aerators @ 37 kW each
(20 kW/1000 m3 of Basin Volume)
Secondary Clarifier
Overflow Rate: (2QQ
Polishing Pond (under present average flow conditions):
Detention Time: 86 days
14
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TABLE 6 - OPERATING COST OF ANAEROBIC
LAGOON/EXTENDED AERATION PROCESS (PLANT C)
Capital Cost Not Available
Operating Costs:
Manpower: 2080 hr/yr @ $10/hr $20,800
Electrical Power: 1.1 x 10 kW-hr/yr x
$0.025/kW-hr $28.000
Annual Operating Cost $48,800
15
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As shown in Figure 5, plant wastewater is collected in a small sump and
pumped to a vibrating screen for separation of gross solids. From here
it flows to an oxidation ditch, and finally to a secondary clarifier
prior to discharge to a small creek. Sludge from the clarifier bottom
may be either returned to the ditch or drawn off for discharge to
drying beds.
Operating and design criteria for the oxidation ditch installation are
presented in Table 7.
The wastewater flow through the treatment plant is generally between 14
and 29 m /day (3,000 and 6,500 Igpd), 5 days per week. With few exceptions,
the process has consistently been able to achieve effluent BOD,, and
suspended solids concentrations of less than 40 and 50 mg/L respectively,
despite the concentrated and variable nature of the waste. This corresponds
to removals of 98% and 90% for BOD and suspended solids, respectively.
The oxidation ditch was constructed in 1963. No data are available on
the capital cost of the plant, however, annual operating costs are
estimated at less than $3,000, as calculated in Table 8.
The operational requirements of the process have been found to be minimal.
Return sludge from the secondary clarifier is wasted, as required, by
discharging it directly to sludge drying beds located on the plant
property. Sludge settleability, pH, and dissolved oxygen are measured
on a regular basis.
Due to low alkalinity of the wastewater, sodium bicarbonate must be
added to provide buffering capacity and to stabilize pH in the 6.5 to
7.0 range. Prior to the addition of sodium bicarbonate, the process was
operating relatively unsuccessfully at a pH of approximately 4.7.
Plant E
Plant E is a hog processing and rendering operation, slightly larger
than Plant C, slaughtering approximately 5,000 hogs per 8 hour day, 5 to
6 days/week.
The wastewater treatment facility is a trickling filter process preceded
by anaerobic lagoons. Pretreatment of wastes from the kill floor consists
of screening followed by air flotation. Effluent from the flotation
unit is combined with other processing and domestic wastewater, and sent
to two anaerobic lagoons operated in parallel for biological treatment
and flow equalization. Lagoon effluent is then preaerated and pumped to
two plastic media trickling filter towers operated in series. Secondary
clarification in two parallel clarifiers and disinfection of effluent is
then carried out prior to discharge to a nearby river. Sludge from the
clarifiers is returned to the anaerobic lagoons for digestion. A schematic
flow diagram of the process is illustrated in Figure 6.
16
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OXIDATION DITCH
WASTE SLUDGE
TO -"
DRYING QEDS
RETURN
SLUDGE
OXIDATION
DITCH
EFFLUENT
SECONDARY
CLARIFIER
DISCHARGE TO
CREEK
FIGURE 5 - Schematic Flow Sheet of Waste Treatment Process
(Plant D)
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TABLE 7 - DESIGN AND OPERATING CRITERIA FOR
OXIDATION DITCH PROCESS (PLANT D)
Wastewater Characteristics:
3
Flow: Average - 26 m /day (5700 Igpd) - 5 days/week
(Majority of Daily Flow Occurs in 8-10 hr period)
Range: 500 - 7,000 mg/L
Average: 2,200 mg/L
SS:
Range: 400 - 1,400 mg/L
Average: 600 mg/L
Oxidation Ditch:
Organic Loading Rate:
MLSS Concentration:
0.12 kg BOD /kg MLSS/day
Volumetric Loading Rate: 368 g BOD /day/m"
(23 Ib BOD5/1,000 ft /day)
3,000 mg/L
Detent ion Tirae:
5.8 days
Aeration Requirements:
3.7 kW Cage Rotor
3
(25 kW/1000 m of basin volume)
18
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TABLE 8 - OPERATING COSTS FOR OXIDATION
DITCH PROCESS (PLANT D)
Capital Cost Not Available
Operating Cost:
Manpower: 260 hr/yr @ $10/hr $2,600
Electrical Power: 7,500 kW-hr/yr x
$0.025/kW-hr .... $ 190
Annual Operating Cost $2,790
19
-------
PUNT E
r
ANAEROBIC
LAGOON
AIR
FLOTATION
TANK
ANAEROBIC
LAGOON
FRE-AERATION TANK
TRICKLING FILTER
TRICKLING FILTER
SPLITTER SOX
CLARIFIER^-X
CLARIFIER
CHLORINE
CONTACT
TANK
EFFLUENT
FIGURE 6 - SCHEMATIC FLOW SHEET OF WASTE
TREATMENT PROCESS (PLANT E)
20
-------
Operating and design criteria for the treatment plant are summarized in
Table 9.
Some problems have been encountered with reduced treatment efficiency
and filter freezing during cold weather operation. The filters, originally
open to the air, have been enclosed to help retain heat and alleviate
this problem. Some clogging of the distributor arms and filter media
has also been experienced; otherwise the trickling filters have operated
with very few problems.
A distinct odour of hydrogen sulphide was evident in the vicinity of the
anaerobic lagoons, but this has reportedly not caused any complaints
from a nearby residential area. Sludge removal from the anaerobic cells
has only been required once to date.
The plant is maintained by a trained operator on a full-time basis and
consistently produces a final effluent with less than 70 mg/L BOD^ and
80 mg/L of suspended solids (greater than 97%"removal of both parameters).
The anaerobic lagoons are providing approximately 60% BOD,, removal and
65% removal of suspended solids.
The treatment plant construction was completed in 1969 at a cost of
$500,000. As shown in Table 10, the estimated total capital cost of
such a project in 1977 dollars is approximately $1,100,000. The annual
operating and maintenance cost of the facility is estimated at approximately
$40,000.
DAIRIES AND MILK PRODUCTS PLANTS
Plant F
Plant F is a dairy operation with a peak milk production of approximately
195,000 kg (430,000 Ibs) of raw milk per day. The principal products
are butter, dried milk, and skim milk powder. Plant production is
highly seasonal. During the peak production season (summer), the plant
operates 24 hours per day, 7 days/week. This drops off to a 16 hour/day,
5 day/week production schedule as the availability of raw milk decreases.
The plant has been forced to shut down during the winter season in
recent years due to insufficient supplies of raw milk to warrant operation.
An oxidation ditch process, as shown in Figure 7, is used to treat an
average wastewater flow of 160 m^/day (35,000 Igpd). Wastewater is
collected in a wet-well and pumped to a 25 m^ (5,500 gallon) equalization
tank. The waste flows from the bottom of the tank, at a rate proportional
to static head of liquid in the tank, into an open channel to the oxidation
ditch. Overflow from the ditch enters a secondary clarifier housed in a
small building which also contains the sludge return pumps. Clarified
effluent is discharged to a nearby river.
Design and operating criteria are summarized in Table 11.
21
-------
TABLE 9 - OPERATING AND DESIGN CRITERIA FOR ANAEROBIC
LAGOON/TRICKLING FILTER PROCESS (PLANT E)
Wastewater Characteristics:
Flow: Range: 1820 - 3180 m3/day (400,000 - 700,000 Igpd)
Average: 2730 m /day (600,000 Igpd)
BOD : Range: 2,000 - 5,000 mg/L
Average: 3,000 mg/L
SS:
Range: 2,000 - 4,000 mg/L
Average: 3,000 mg/L
Anaerobic Lagoons:
Organic Loading: 320 g BOD^/day/nT
(20 Ib BOD 71,000 ft /day)
Depth:
4.3 m (14 ft)
Detention Time: 9.7 days
Trickling Filters:
Organic Loading
Filter No. 1 Filter No. 2
kg BOD /day /m)
(Ib BOD5/1,000 ft3/day)
Hydraulic Loading
3 2
(m /day/m )
(Igpd/ft2)
Depth (m)
Media
864
54
24
500
6.7
PVC
384
24
24
500
6.7
PVC
Secondary Clarifiers:
32 2
Overflow Rate: 28 m /day/m (565 Igpd/ft )
22
-------
TABLE 10 - PROCESS PERFORMANCE AND COST OF ANAEROBIC
LAGOON/EXTENDED AERATION PROCESS (Plant E)
Capital Cost (adjusted to 1977) $1,100,000
Annual Amortized Capital Cost @ 11% $121,000
Operating Cost:
Manpower: 2080 hr/yr @ $10/hr $20,800
Electrical Power: 149,000 kW-hr/yr x
$0.025/kW-hr $ 3,700
Maintenance Allowance $15,000
Annual Operating Cost $ 39,500
Total Annual Cost $160,500
3
Cost per m Treated $0.23
($1.03/1000 I.G.)
Cost per kg BOD Removed $0.077
($0.035/lb)
23
-------
PLANT F
OXIDATION
OITCH
RAW
WASTEWA1
EQUALIZATION
TANK
'ER
RETURN
•— -,SL]JDGE_
I
I
T
WASTE SLUDGE TO
SPRAY IRRIGATION OR
SLUDGE DRYING BEDS
FIGURE 7 - SCHEMATIC FLOW SHEET OF WASTE TREATMENT PROCESS
(PLANT F)
FINAL EFFLUENT
TO RIVER
24
-------
TABLE 11 - OPERATING AND DESIGN CRITERIA FOR
OXIDATION DITCH PROCESS (PLANT F)
Wastewater Characteristics:
Flow: Summer: 160 - 180 m3/day (35,000 - 40,000 Igpd)
Winter: 45 - 55 m3/day (10,000 - 12,000 Igpd)
Design Flow: 160 m /day (35,000 Igpd)
BOD5: Range: 500 - 1900 mg/L
Average: 950 mg/L
SS: Range: 600 - 2500 mg/L
Average: 1240 mg/L
Oxidation Ditch:
Depth: 1.5 m (5 ft)
Detention Time: 3.1 days
MLSS Concentration: 4,000 mg/L
Organic Loading: 0.076 kg BOD /kg MLSS/day
3
Volumetric Loading: 300 g BOD /day/m
(19 Ib BOD /1000 ft3/day)
3
Aeration Requirements: 19 kW Cage Rotor (21 kW/1000 m )
Clarifier:
Diameter: 4.3 m (14 ft)
Overflow Rate: 11 m3/day/m2 (230 Igpd/ft )
25
-------
Sludge is wasted from the process on a daily basis in summer months by
means of spray irrigation on 7.3 hectares (18 acres) of plant property.
Sludge wasting occurs only intermittently in winter to sludge drying
beds.
The major problem encountered in operation of the plant has been the
loss of solids from the secondary clarifier due to flow surges. While
the equalization tank provides some balancing of flow, this is-insufficient
to prevent the rising of the sludge blanket in the clarifier and subsequent
loss of solids during extended periods of high flow.
The clarifier design is such that settled sludge has a tendency to cling
to the conical sides and bottom. This necessitates daily scraping to
remove the sludge and prevent problems of septicity and denitrification
from occurring.
Some problems with ice formation on the aeration rotor have also been
encountered in winter operation.
The oxidation ditch process has performed very effectively with 99% BOD,-
removal and 98% removal of suspended solids. Average effluent concentrations
of BODp and suspended solids are 7 mg/L and 28 mg/L,respectively.
The plant operator spends approximately one hour per day maintaining the
plant. This involves a daily sludge settleability test, scraping of the
clarifier bottom and a weekly BOD,, analysis.
The waste treatment plant was constructed in 1972 at a cost of approximately
$70,000. As shown in Table 12, the updated value of the plant is estimated
at $110,000, and annual operating costs at $6,600.
Plant G
Plant G is a condensed milk operation that processes an average of
approximately 159,000 kg (350,000 Ibs) of raw milk per day. Plant
production is highly seasonal, depending upon availability of raw milk,
although production is generally carried out 8 hours/day, 6 days/week.
As shown in Figure 8, the waste treatment process employed by Plant G,
consists of a combined extended aeration, trickling filter process. The
average daily flow of 160 m^/day (35,000 Igpd) is passed through a
grease trap and screen prior to reaching a preaeration basin. Wastewater
from the preaeration cell is pumped at a constant rate of 38 L/s (500
Igpm) to a trickling filter with rock media. Underflow from the trickling
filter is returned to the preaeration basin and overflow from this cell
enters a second aerated cell, which carries a much higher concentration
of mixed liquor suspended solids. Effluent from this stage in turn
passes to a third aeration basin and finally to a rectangular clarifier
prior to discharge to a municipal sewer.
26
-------
TABLE 12 - CAPITAL AND OPERATING COSTS FOR
OXIDATION DITCH PROCESS (PLANT F)
Capital Cost (adjusted to 1977)
Annual Amortized Cost @ 11%
$110,000
$12,100
Operating Costs:
Manpower: 260 hrs/yr x $10/hr $ 2,600
Electrical Power: 160,000 kW-hrs/yr x
$0.025/kW-hr .
$ 4,000
Annual Operating Cost
Total Annual Cost
$6.600
$18,700
Cost per m Treated
$0.32
($1.46/1000 I.G.)
Cost per kg BOD,. Removed
$0.35
($0.16/lb)
27
-------
RETURN SLUDGE
_WASJE_
SLUDGE
SPRAY IRRIGATION
OF SLUDGE
WASTEWATER
FINAL
EFFLUENT
FIGURE 8 - SCHEMATIC FLOW SHEET OF WASTE
TREATMENT PROCESS (PLANT G)
28
-------
Operating and design criteria for the plant are summarized in Table 13.
Sludge removed from the clarifier bottom is returned to the second
aeration basin. In summer months, approximately 6.8 m^ (1,500 I.G.) of
return sludge are wasted per week by spraying on plant property.
Problems which have been encountered with the trickling filter include
ice buildup in winter months and some filter fly nuisance in summer.
Many problems have occurred with clogging of the carborundum type air
diffusers in the aeration basins. This has necessitated daily brushing
and frequent removal of the diffusers to prevent excessive pressure
buildup in the aeration piping.
Discharges of high concentrations of suspended solids has been another
problem with the process. Since the majority of the total daily flow
occurs in the last 3 hours of an 8 hour shift, during wash-up operations,
a flow surge occurs. This results in increased overflow rates in the
secondary clarifier and the resultant loss of solids.
Approximately one hour per day is spent in maintaining the plant. When
operating well, an effluent BOD concentration of less than 25 mg/L and
less than 100 mg/L of suspended solids is generally achieved.
An estimate of the capital cost of the waste treatment facility was not
available, but annual operating costs are estimated at approximately
$6,000 as shown in Table 14.
Plant H
Plant H is a 24 hour/day, 7 day/week milk processing operation. The
main products are cheese and butter, with dried whey being sold as a by-
product.
The waste treatment facility consists of a 7-stage RBC unit followed by
aerated lagoons. As shown in Figure 9, aqueous ammonia is added to the
flow equalization/preaeration basin ahead of the RBC unit, due to a
nitrogen deficiency in the waste. Intermediate clarification follows
the first three stages of RBC treatment. Effluent from the intermediate
clarifier is then further treated in an additional four RBC stages, and
discharged to a secondary clarifier. Secondary clarifier effluent is
subsequently passed through a 2-cell aerated lagoon system, and a settling
basin prior to discharge. The wastewater flow of 590 m^/day (130,000 Igpd)
is relatively consistent year-round.
Operating and design criteria for the waste treatment process are summarized
in Table 15.
The plant is maintained by one operator on a full time (8 hour/day, 5
day/week) basis, who monitors the process daily.
29
-------
TABLE 13 - OPERATING AND DESIGN CRITERIA FOR EXTENDED
AERATION/TRICKLING FILTER PROCESS (PLANT G)
Wastewater Characteristics:
Flow: Range: 114 - 295 m3/day (25,000 - 65,000 Igpd)
Average: 160 m /day (35,000 Igpd)
BOD : Range: 300 - 2,200 mg/L
Average: 1,000 mg/L
SS: Range: 150 - 500 mg/L
Average: 300 mg/L
Trickling Filter:
Depth: 1.4 m (4.5 ft)
Diameter: 21.4 m (70 ft)
Organic Loading Rate: 320 g BOD /day/m3 (20 Ib BOD /1000 ft3/day)
32 2
Hydraulic Loading Rate: 0.44 m /day/m (9 Igpd/ft )
Media: Rock
Extended Aeration Process:
1st Cell: Detention Time - 18 hours
2nd Cell: Detention Time - 15 hours
3rd Cell: Detention Time - 24 hours
Overall Aeration Requirements:
Diffused Aeration
(41 kW/1000 m3 of basin volume)
Secondary Clarifier:
Overflow Rate - 6.8 m3/day/m (140 Igpd/ft )
30
-------
TABLE 14 - OPERATING COSTS FOR THE EXTENDED
AERATION/TRICKLING FILTER PROCESS (PLANT G)
Costs:
Capital Cost Not Available
Operating Costs:
Manpower: 260 hrs/yr x $10/hr $2,600
Electrical Power: 131,400 kW-hrs/yr x
$0,025/kW-hr $3,300
Annual Operating Cost $5,900
31
-------
10 DAY EMERGENCY
HOLDING POND
3 STAGE R8C
INTERMEDIATE
CLARIFIER
RAW
WASTE;
AMMONIA
PREAERATION/FLOW
EQUALIZATION BASIN
SECONDARY
CLARIFIER
4 STAGE R8C
7
6
5
4
WASTE SLUDGE
8 DAY
AERATED
LAGOON
,
^C
WASTE
SLUDGE
SLUDGE
ENTRIFUGE
I
I
I
Y
SLUDGE
DISPOSAL
10 DAY
SEDIMENTATION
8ASIN
FIGURE 9 - SCHEMATIC FLOW SHEET OF WASTE
TREATMENT PROCESS (PLANT H)
32
-------
TABLE 15 - OPERATING AND DESIGN CRITERIA FOR RBC/
AERATED LAGOON PROCESS (PLANT H)
Wastewater Characteristics:
3
Flow:
BOD :
SS:
590 m /day (130,000 Igpd)
3,400 mg/L
3,200 mg/L
- little variance
Preaeration/Flow Equalization Basin:
Volume: 455 m3 (100,000 I.G.)
Detention Time: 18 hours
First 3 RBC Stages:
Surface Area per stage:
Organic Loading Rate:
Hydraulic Loading Rate:
16,700 m2 (180,000 ft2)
40 g/day/m2 (8.2 Ib BOD5/1000 ft2/day)
0.012 m3/day/m2 (0.24 Igpd/ft2)
Intermediate Clarifier:
Overflow Rate:
36 m3/day/m2 (735 Igpd/ft2)
Last 4 RBC Stages:
Surface Area per stage:
Hydraulic Loading Rate:
16,700 m2 (180,000 ft2)
0.0088 m3/day/m2 (0.18 Igpd/ft2)
Secondary Clarifier:
Overflow Rate:
36 m3/day/m2 (735 Igpd/ft2)
Aerated Lagoons:
First Cell:
Detention Time - 2 days
3 3
Organic Loading - 320 g/day/m (20 Ib BOD,/1000 ft /day)
Second Cell: Detention Time - 8 days
Aeration Requirements - Diffused Air with 3 blowers @ 75 kW each to aerate
preaeration basin plus both aerated lagoon cells
- Only one blower in use at present
- Average overall aeration requirements =
12 kW/1000 m3 (72 hp/MIG)
Final Settling Basin: Detention Time - 10 days
33
-------
The RBC/aerated lagoon process has performed exceptionally well and
demonstrated an ability to attain very high treatment efficiencies. The
RBC system with secondary clarifier is achieving approximately 90%
removal of BOD and 86% suspended solids removal. Final effluent from
the aerated lagoon system contains less than 25 mg/L of BOD and suspended
solids, for overall removals in excess of 99% for both parameters.
The major difficulty that has been encountered with the operation of
this plant has been the handling of voluminous amounts of waste sludge
produced by the RBC process. Sludge collected from the intermediate and
secondary clarifiers is dewatered in a centrifuge and hauled away for
spreading on 65 hectares (160 acres) of pasture land. Approximately 9
m-Vday (2,000 Igpd) of dewatered sludge must be disposed of in this
fashion.
As shown in Table 16, the estimated present value of the plant is
approximately $815,000. It was constructed in 1975 at a cost of $700,000.
Operating costs are estimated at approximately $47,000 annually.
FRUIT AND VEGETABLE PROCESSING PLANTS
Plant I
Plant I is a potato processing plant operating 24 hours/day, 5 to 6 days
per week. It processes an average 0.68 million kilograms (1.5 million
pounds) of potatoes per day.
3
The average wastewater flow of 2800 m /day (625,000 Igpd) is treated by
a high rate trickling filter (biofilter) process as illustrated in
Figure 10. In-plant pretreatment processes consist of a mud pit for
removal of field stones, dirt and sprouts from the fluming water, a
grease trap for removal of free floating grease from the french fry
operation, and scalping and vibrating screens for gross solids removal
from the combined wastewater stream.
Screened wastewater is passed through a primary clarifier and then to
two high rate plastic media trickling filters operated in series with
interstage settling. Effluent from the second trickling filter flows to
a secondary clarifier prior to discharge to a river. A fraction of the
final effluent is also recirculated to the first trickling filter.
Operating and design criteria for the plant are summarized in Table 17.
Sludge removed from the primary clarifier is dewatered on a vacuum
filter prior to being hauled some 18 km (11 miles) to a lagoon for final
disposal. Secondary sludge is pumped directly to a dewatering and
digestion lagoon located on the premises. Supernatant from this lagoon
is returned to the trickling filters, with the dried sludge being removed
by means of a front end loader and disposed of on land.
34
-------
TABLE 16 - CAPITAL AND OPERATING COST DATA FOR THE
RBC/AERATED LAGOON PROCESS (PLANT H)
Capital Cost (adjusted to 1977) ....... $815,000
Annual Amortized Capital Cost @ 11% $89,700
Operating Costs:
Manpower: 2080 hrs/yr x $10/hr $21,000
Electrical Power:
980,000 kW-hr/yr x $0.025/kW-hr .... $24,500
Chemicals: $ 1,400
Annual Operating Cost $46,900
Total Annual Cost $136,600
3
Cost per m Treated $0.63
($2.87/1000 I.G.)
Cost per kg BOD Removed $0.19
$0.085/lb)
35
-------
PROCESS WASTEWATER
SCREENING^
WASTE
PRIMARY \ SLUDGE | VACUUM
CLARIFIER I *! FILTER
HAULED TO
LAGOON FOR
DISPOSAL
SLUDGE
TO DIGESTION/
DEWATERING
LAGOON
FINAL EFFLUENT
FIGURE 10 - SCHEMATIC FLOW SHEET OF WASTE
TREATMENT PROCESS (PLANT I)
36
-------
TABLE 17 - OPERATING AND DESIGN CRITERIA FOR HIGH RATE
TRICKLING FILTER PROCESS (PLANT I)
Wastewater Characteristics:
Flow: Range: 2640 - 3050 m3/day (580,000 - 670,000 Igpd)
Average: 2800 m /day (625,000 Igpd)
BOD : Range: 1700 - 4800 mg/L
Average: 2,500 mg/L
SS: Range: 900 - 4200 mg/L
Average: 2,000 mg/L
Primary Clarifier:
Diameter: 20 m (65 ft)
Overflow Rate: 9.8 m3/day/m2 (200 Igpd/ft2)
Trickling Filters:
Dimensions: 12 m x 12 m x 6 m deep (40 ft x 40 ft x 20 ft deep) (each)
Media: Plastic Flocor
Hydraulic Loading: 0.038 m3/day/m2 (0.78 Igpd/ft2)
(including recirculation)
Organic Loading: 10,000 g/day/m3 (675 Ib BOD5/1000 ft3/day)
(first biofilter including recirculation)
Recirculation Ratio: 1.6:1
Secondary Clarifier: Diameter - 17 m (55 ft)
37 m3/d
(including recirculation)
Overflow Rate - 37 m3/day/m2 (750 Igpd/ft2)
Sludge Digestion/Dewatering Lagoon:
Depth: 1.8 m (6 ft)
Design Storage: 100 - 300 days
2 2
Design Solids Loading: 107 kg/m /yr (22 Ib/ft /yr)
37
-------
A number of operating problems were encountered with the waste treatment
facility shortly after placing it into operation in 1971, but these have
been largely overcome. Grease and fibres in the wastewater caused a
clogging problem with the spray nozzles on the biofilters necessitating
their frequent cleaning. A modified distribution system has been installed
to alleviate this problem.
Caustic spills in the plant have occasionally resulted in wastewater pH
values in excess of 9.0. These have caused damage to the biological
film on the media, which requires one to two days to recover.
While the pH of the raw wastewater entering the primary clarifier is
near neutral, the primary sludge pH is usually in the range of 4.3 to
4.5 when removed. This is apparently due to biological activity within
the sludge. As a result, it was found necessary to install an acid
resistant cloth on the vacuum filter for satisfactory sludge dewatering.
Experience has demonstrated that covers over the biofilters would be
useful in preventing the deposition of airborne leaves and dirt on the
media. This would also assist in retaining heat lost during winter
operation.
The discharge of high concentrations of suspended solids in the treatment
plant effluent was also encountered after start-up. Sodium aluminate is
now added to the waste to promote the development of floes in the secondary
clarifier and improve sedimentation. The chemical is added ahead of the
second trickling filter to ensure adequate mixing.
The high rate trickling filter process has performed effectively as a
roughing unit, as intended, and has achieved relatively consistent BOD
and suspended solids removals of approximately 85%. Final effluent
concentrations of the two parameters have averaged 380 mg/L and 280 mg/L,
respectively. Due to the high assimilative capacity of the receiving
stream to which the effluent from this plant is discharged, more stringent
effluent limitations have not been required by regulatory agencies.
The plant performance is closely monitored by five operators and a
laboratory technician, with suspended solids analyses made daily and
measured two or three times per week.
The plant was constructed in 1971 at a total cost of $1,165,000. The
updated value of the plant is estimated at approximately $2.0 million
and annual operating costs at $61,750, as shown in Table 18.
38
-------
TABLE 18 - PERFORMANCE AND COST DATA FOR HIGH RATE
TRICKLING FILTER PROCESS (PLANT I)
Capital Cost (adjusted to 1977) $2,000,000
Annual Amortized Cost @ 11% $220,000
Operating Costs:
Manpower: 3,000 hrs/yr x $10/hr $30-,000
Electrical Power: 650,000 kW-hr/yr x $0.025/
kW-hr $16,250
Chemicals: $ 1,500
Sludge Hauling: , . . $14,000
Annual Operating Cost $ 61,750
Total Annual Cost $281,750
3
Cost per m Treated $0.35
($1.58/1000 I.G.)
Cost per kg at BOD Removal $0.16
($0.074/lb)
39
-------
Plant J
The wastewater from Plant J consists of effluent from the processing of
fresh fruit juices and sauces. The principal products from the plant
are the following:
1) apple, pear, grape and apricot juices, and juice concentrates,
2) cherry, peach, apple, raisin, and blueberry pie filling,
3) apple sauce,
4) citrus juices made from juice concentrates.
The plant operates 24 hours/day, five days/week on a year round basis.
The daily schedule consists of 16 hours of processing followed by an
eight hour clean-up shift.
Wastewater from Plant J flows to an extended aeration treatment facility
which also handles the. wastewater from a winery and distilled liquor
plant. Although only the cumulative flow data for the two plants were
available, the majority of the wastewater is produced by the juice
processing plant.
The total-annual flow to the wastewater treatment plant is approximately
182,000 m (40 MIG). Monthly flows vary from 6,800 m to 27,000 m
(1.5-6 MIG) with large fluctuations occurring in the daily flow rate.
A schematic of the extended aeration treatment plant is illustrated in
Figure 11. Effluent from the food processing plant is passed over a 40
mesh horizontal vibrating screen for coarse solids removal. Prior to
entering the wet-well all wastewater is also passed through a 1.9 cm
(3/4 inch) mesh coarse screen. In the wet-well provision has been made
for the addition of nitrogen (aqua ammonia) and phosphorus (phosphoric
acid). At the present time only nitrogen is added; there is sufficient
phosphorus from the soaps in the cleaning water to supply bacterial
growth requirements. Recirculated sludge is returned from the secondary
clarifiers to the wet well and mixed with the raw wastewater. The
aeration basin contains three 56 kW (75 hp) mechanical surface aerators.
Solids are removed from the mixed liquor in two 10.6 m (35 ft) diameter
clarifiers operated in parallel. The clarified effluent is then chlorinated
prior to discharge to an adjacent creek. A portion of the sludge is
returned to the headworks of the plant while the remainder is thickened
by centrifuging and then removed by tank truck for final disposal to
land. The centrate is returned to the headworks of the plant.
Operating and design criteria for the plant are outlined in Table 19.
40
-------
FOOD-PROCESSING WASTEWATER
VIBRATING SCREEN
WINERY
WASTEWATER
RETURN
SLUDGE
DISCHARGE
TO
CREEK
SOLIDS TO TANK TRUCK
FIGURE H SCHEMATIC OF WASTEWATER TREATMENT PLANT
(PLANT J)
41
-------
TABLE 19 - OPERATING AND DESIGN CRITERIA FOR
EXTENDED AERATION PROCESS (PLANT J)
Wastewater Characteristics:
Flow: Range:
340 - 1820 m /day (75,000 - 400,000 Igpd)
3
Average: 700 m /day (154,000 Igpd)
Design Flow:
2270 m /day (500,000 Igpd)
BOD:
SS:
1,500 mg/L
420 mg/L
Extended Aeration Process:
Detention Time (aeration basin)
Aeration Basin Volume:
Aeration Basin Depth:
MLSS Concentration
8 days
5,675 m3 (1.25 MIG)
3.7 m (12 ft)
3,000 - 5,000 mg/L
Organic Loading:
Volumetric Loading:
Solids Retention Time:
Aeration Requirements:
0.05 kg BOD /kg MLSS/day
3
184 g BOD /day/m
3
(11.5 Ib BOD5/1000 ft /day)
30 - 40 days
3 mechanical surface aerators @
56 kW ea. (30 kW/1000 m3 of
basin volume)
Clarifiers (2):
Diameter:
Overflow Rate:
Sludge Wasting Rate: 1135 kg/day (2,500 Ib/day)
11 m (35 ft)
32 2
3.9 m /day/m (80 Igpd/ft ) at average flow
42
-------
Under present operating conditions the plant is achieving a BOD removal
efficiency of 99% and a suspended solids removal efficiency of 96%.
Effluent concentrations of the two parameters average 10 mg/L and 13
mg/L,respectively.
Operating problems were experienced initially due to ice formation on
the aerators during winter operation. To alleviate this problem, warm
cooling water which is normally discharged directly to the creek is
diverted to the aeration basin during January and February.
Problems have also been encountered with the formation of floating
sludge in the secondary clarifiers. This is caused by the adherance of
sludge to the thickener machinery for extended periods of time and has
been -most prevalent during the cherry processing season.
Problems of biological process stability have not occurred despite the
fact that the food processing plant only discharges wastewater five days
each week, and the daily loadings are highly variable.
Capital and operating costs for the wastewater treatment facility are
summarized in Table 20. The plant was completed in 1973 at a cost of
$750,000 including land. This corresponds to an estimated 1977 value of
$1,100,000. The actual 1977 operating costs reported by the plant were
approximately $83,000, as shown. The total annual cost and unit costs
of treatment are relatively high, considering the average wastewater
flow presently being treated at this plant. This can be attributed to
two factors, as follows:
1) Since the plant was designed for an average flow rate
considerably in excess of that presently being treated, the
capital cost incurred in its construction was appreciably
higher than would have been, had a smaller plant, designed
only for the current average wastewater flow, been constructed.
As a capital amortization cost allowance is included in the
calculation of total annual cost, and subsequently in the
calculation of unit treatment costs, these costs reflect this
high construction expense.
2) The operating costs presented in Table 20 are those actually
reported by plant personnel, rather than as calculated for
previous plants, using simply the manpower and electrical
requirements of the process. Items such as the engineering
cost allocation, and administration costs, which contribute
significantly to the annual operating cost in this case, have
not been estimated for other plants due to the highly variable
nature of these costs from plant to plant and the obvious
difficulty in attempting to derive a reliable estimate of
this operating expense for each particular plant.
43
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TABLE 20 - CAPITAL AND OPERATING COSTS FOR EXTENDED
AERATION TREATMENT PROCESS (PLANT J)
Capital Cost (adjusted to 1977) $1,100,000
Annual Amortized Cost @ 11%
$121,000
Operating Costs:
Manpower: $27,800
Electrical Power: 7,800
Equipment Maintenance: 4,000
Sludge Handling 1,200
Plant Monitoring and Laboratory
Analysis 7,350
Engineering Cost Allocation 13,800
Administration 15,000
Miscellaneous 6,000
Annual Operating Cost
$ 82,950
Total Annual Cost
$203,950
Cost per m Treated
$1.12
($5.10/1000 I.G.)
Cost per kg of BOD,. Removed
$0.75
($0.34/lb)
44
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Operational staff consists of a foreman who is also responsible for the
operation of the municipal sewage treatment plant, a full-time subforeman
and a plant operator who spends approximately 80% of his time at the
food-processing wastewater treatment plant.
Operation of the plant is monitored continuously with automatic samplers
and flow metering equipment. Composite samples of influent and effluent
wastewater are collected daily and subjected to COD tests. Temperature
and pH are monitored daily. BOD and total suspended solids concentrations
are determined twice weekly and nutrient (N & P) concentrations in the
effluent are determined weekly.
Composite recirculated sludge samples are also collected regularly.
Total suspended solids are determined three times per week and volatile
suspended solids are determined twice weekly. The data are used to
monitor sludge density to facilitate control of the sludge recirculation
rate, and to monitor sludge activity in order to control the mixed
liquor suspended solids concentration.
BEVERAGE INDUSTRY
Plant K
Plant K is a distillery which processes approximately 145 tonnes (160
tons) of corn, rye and barley malt per day on a 24 hour/day, 5
day/week basis. The plant presently operates only seven months per
year. Main products are beverage and industrial alcohol, with fusel oil
and high protein livestock feed material recovered as by-products.
Wastewater originates from equipment and floor washings, evaporator
condensate, boiler blowdown, gin still bottoms and rectifier bottoms.
The average daily flow of 908 m3 (200,000 I.G.) is discharged to a
45 m3 (10,000 I.G.) sump. From here, two pumps controlled by level
switches lift the wastewater to the treatment plant.
Wastewater treatment consists of extended aeration followed by secondary
clarification and a polishing lagoon, as illustrated in Figure 12.
The operating and design criteria for the plant are summarized in Table 21.
Clarifier and lagoon effluents are monitored weekly by the plant operator
for COD and suspended solids. A high quality effluent has generally
been achieved with removals in excess of 95% and 90% for these two
parameters respectively. Effluent from the secondary clarifier generally
has a COD of less than 60 mg/L and this is further reduced to less than
50 mg/L in the lagoon. The lagoon reduces the suspended solids concentration
in the clarifier effluent from approximately 20 mg/L to less than 15 mg/L.
Sludge is usually wasted on a monthly basis to drying beds located on
the plant property.
45
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PLANT WASTEWA-TER
SUMP
NUTRIENT ADDITION
AERATION
BASIN
SECOND*RY
CLARIF1ER
WASTE SLUDGE
SLUDGE
DRYING
BEDS
POLISHING
LAGOON
DISCHARGE TO RIVER
FIGURE 12 - SCHEMATIC FLOW SHEET OF WASTE
TREATMENT PROCESS (PLANT :<}
46
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TABLE 21 - OPERATING AND DESIGN CRITERIA FOR EXTENDED
AERATION/POLISHING LAGOON PROCESS (PLANT K)
Wastewater Characteristics:
Flow: Low: 23 m /day (5,000 Igpd) - weekends
Peak: 2050 m3/day (450,000 Igpd)
3
Average: 1000 m /day (220,000 Igpd) - 5 days/week
BOD: Average approximately 800 mg/L
COD: 1,000 - 1,500 mg/L
SS: 200 - 300 mg/L
Extended Aeration Process:
Organic Loading Rate: 0.16 kg BOD /kg MLSS/day
n
Volumetric Loading Rate: 800 g/day/m3 (50 Ib BOD5/1000 ft /day)
MLSS Concentration:
Detention Time:
2,000 - 8,000 mg/L
24 hours
Aeration Requirements: 2 Mechanical Surface Aerators @ 19 kW ea.
3
(4 kW/1000 m of basin volume)
Polishing Lagoon:
Depth:
Detention Time:
1.2 m (4 ft)
5 days
47
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The wastewater has been found to be deficient in both nitrogen and
phosphorus. This is compensated for by a weekly addition of 45 kg
(100 Ibs) of urea and 23 kg (50 Ibs) of sodium dihydrogen phosphate to
the wastewater sump.
It has been found necessary to chip ice from around the aerators during
winter months. Some freezing problems with the clarifier have also been
encountered in cold weather.
Since the distillery is operated only seven months per year, the waste
treatment plant must be re-started when production commences. The
start-up period usually requires from 7 to 10 days, although in cold
weather this may be extended to 21 days.
Plant operation is the responsibility of a lab technologist, who spends
approximately 4 to 5 hours per week monitoring plant performance and
making adjustments as necessary. An additional hour per week is spent
inspecting and lubricating mechanical equipment and adding the necessary
nutrients.
As shown in Table 22, the estimated present value of the plant is
approximately $1,020,000. It was originally constructed in 1969 at a
cost of $490,000. Annual operating costs are estimated at approximately
$7,500.
FISH PROCESSING INDUSTRY
Plant L
Plant L is a salmon processing plant that produces fresh, fresh-frozen
and smoked-fish products. In addition to salmon, the plant processes
aquaculture fish, primarily rainbow trout and immature salmon. The
salmon processing season runs for approximately six months with the
processing of aquaculture fish occurring during the remaining six months
of the year. The plant operates on a 6-1/2 hour/day, five day per week
schedule.
Wastewater originates as washwater from fish cleaning and gutting operations,
and as table and floor washdown water. During the salmon processing
season, flows vary from 1.4 to 4.5 m^/day (300 to 1,000 Igpd) with an
average flow rate of 2.6 m-Vday (580 Igpd). -While processing aquaculture
fish, these increase to an average of 13.6 m /day (3,000 Igpd).
The wastewater treatment system is an extended aeration process as
illustrated in Figure 13. Raw wastewater flows to a wet-well where
grinder pumps lift it to an aeration basin. Aeration is provided by a
3.7 kW (5 hp) mechanical surface aerator. Overflow from the aeration
basin then enters a clarifier. Settled sludge is returned to the aeration
basin from the clarifier by means of an air lift pump. Clarified effluent
is discharged to a polishing pond which acts as an exfiltration basin.
48
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TABLE 22 - CAPITAL AND OPERATING COSTS OF EXTENDED
AERATION/POLISHING LAGOON PROCESS (PLANT K)
Costs:
Capital Cost (adjusted to 1977) $1,020,000
Annual Amortized Capital Cost @ 11% $112,200
Operating Costs:
Manpower: 6 hrs/wk x 30 wks/yr x $10/hr . . . $1,800
Chemicals (nutrients): $1,000
Electrical Power: 50 hp x 0.746 kW/hp x
5,040 hr/yr x $0.025/
kW-hr $4,700
Annual Operating Cost $ 7,500
Total Annual Cost $119,700
Cost per m Treated $0.63
($2.85/1000 I.G.)
Cost per kg BOD Removed $0.79
($0.36/lb)
49
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RAW CHARACTERISTICS
EXTENDED
AERATION
BASIN
CLAR1FIER
DISPOSAL OF EFFLUENT
TO POLISHING PONDS
SLUDGE
RETURN
SLUDGE DISPOSAL
FIGURE 13 - SCHEMATIC FLOW DIAGRAM OF EXTENDED AERATION
WASTE TREATMENT PROCESS (PLANT L)
50
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Table 23 summarizes design and operating criteria for the plant.
Wastewater flows have continuously been much lower than the design flows
during operation of the plant. Although BOD removal efficiencies have
been within the acceptable range for an extended aeration system (i.e.
greater than 90%), suspended solids removal efficiencies have been less
than 65%. Apparently this has resulted from the extremely long retention
times and overaeration of the mixed liquor. This results in the auto-
oxidation of the biological floe, producing a pin-floe which is extremely
difficult to settle.
Other operational problems of the treatment system are listed below:
1) raw wastewater pumps periodically clog with fish bones or
other coarse solids.
2) float level controls in the wet-well become caked with grease.
3) the scum removal system in the clarifier has been inadequate.
In addition, the wastewater usually contains a significant number of
fish eggs during the salmon processing season. The cases from these
eggs become hard and cannot be broken down during the treatment process.
At the time of the field visit, an extended aeration pilot plant was
being used to establish optimum loading rates and aeration requirements.
Preliminary results have indicated that a 24 hour hydraulic detention
time is required to achieve adequate treatment.
The treatment plant was built in 1975 at a capital cost of $80,000. The
updated value of the plant is estimated at $93,000. It has not operated
continuously since that time, as the pilot plant studies currently
utilize most of the wastewater. Operational costs for the large plant
have been minimal. It does not employ an operator, although someone has
been responsible for periodically visiting the plant (approximately
three times weekly). Since the plant has been relatively unused,
maintenance requirements have been very low.
51
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TABLE 23 - OPERATING AND DESIGN CRITERIA FOR
EXTENDED AERATION PROCESS (PLANT L)
Salmon Processing Season
Aquaculture
Fish Processing Season
Wastewater Characteristics:
Flow (m /day):
Range:
Average:
1.4 - 4.5
2.6
7.7 - 18
13.6
BOD5 (mg/L)
COD (mg/L)
SS (mg/L)
690
2000
500
480
810
230
Extended Aeration Process:
Aeration Time
Volumetric Loading
Aeration Requirements
28 days
24 g BOD5/day/m3
(1.5 Ib BOD5/
1000 ft3/day)
50 kW/1000 m3
of basin volume
5.5 days
86 g BOD./day/m3
(5.4 Ib BOD5/
1000 ft3/day)
50 kW/1000 m3
of basin volume
Clarifier:
Overflow Rate
Detention Time
0.29 m3/day/m2
(6 Igpd/ft2)
4.3 days
3 2
1.5 m /day/m
(31 Igpd/ft2)
20 hours
52
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SUMMARY OF GENERAL OBSERVATIONS
In reviewing the operation of biological waste treatment systems at the
numerous food processing plants discussed in this paper, a number of
recurring problems and industry concerns were identified. These are
as follows:
1) treatment plant supervision
2) flow equalization
3) sludge disposal
4) nutrient addition
5) winter operation
6) treatment costs.
The above problem/concern areas warrant further discussion.
Treatment Plant Supervision
Without exception, it was found that the treatment plants operating most
successfully were those which employed a trained, full-time operator.
Due to the variable nature of food processing wastewaters, the potential
for upset of a biological treatment system is relatively high. Despite
claims by a number of treatment equipment manufacturers and distributers,
that their particular process operates with little or no supervision,
very few biological treatment plants are truly capable of consistently
producing an effluent of acceptable quality when treating a waste with
highly variable flow and strength, without close supervision.
This is particularly true of suspended growth systems (i.e. activated
sludge, extended aeration, and oxidation ditch processes) where a number
of problems, such as hydraulic or organic overloading, sludge bulking,
or rising sludge in the secondary clarifier may develop over a relatively
short period of time, resulting in a rapid deterioration in effluent
quality. These problems can only be overcome if a knowledgeable, full-
time operator is on-site to identify them and take the appropriate
corrective action.
A successful operator will be one who is completely familiar with the
particular food processing plant and its associated wastewater character-
istics. In addition, he should be knowledgeable in the fundamentals of
biological treatment and be aware of the potential operating problems
associated with the specific treatment process, their causes and solutions.
Finally, the treatment plant operator should be familiar with the maintenance
and repair of all mechanical equipment, such as pumps, motors and compressors,
upon which the successful operation of the plant relies.
53
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The operator should establish a daily schedule for monitoring the primary
physical, chemical and biological parameters of the process, enabling
him to assess its performance and adjust operating conditions accordingly.
It is recognized that in the case of very small food processing plants,
economics may preclude the ability of the plant to retain a full-time
treatment plant operator. In such cases it is recommended that the
potential for employing alternative methods of treatment and disposal,
requiring considerably less supervision, such as joint municipal/industrial
treatment be thoroughly investigated prior to opting for on-site biological
treatment.
Flow Equalization
In the course of conducting the site visits discussed in this paper, it
became apparent that the majority of food processing plants operate on
an 8 to 10 hour processing period per day, 5 or 6 days per week. The
majority of the daily wastewater flow generally occurs at the end of
this processing shift during the clean-up of equipment, floors and
tables, and the dumping of the contents of product wash tanks, etc.
Overnight and weekend flows are frequently negligible, made up largely
of relatively uncontaminated cooling water.
Many waste treatment facilities which are sized to handle the average
daily wastewater flow have difficulty providing adequate treatment for
flow surges significantly in excess of this average flow. This is
particularly true of some components of the treatment process such as
secondary clarifiers, whose performance is so dependent on flow-through
velocity. On the other hand, hydraulic and organic loadings significantly
below the design rate frequently have a deleterious effect on the biological
reactor stage of the process. The lack of an adequate food source for
extended periods of time results in the microorganisms entering an auto-
oxidation growth phase in which they consume their own cell protoplasm.
This in turn results in the development of a pin floe with poor settling
characteristics.
Both problems can be alleviated by providing sufficient storage capacity
at the front end of the process to permit the flow surges to be temporarily
held back, and fed to the treatment plant during periods of low flow.
Flow equalization can result in significant improvements in effluent
quality from plants experiencing highly variable hydraulic and organic
loading rates. It can also simplify the operation of the plant, and
frequently results in lower capital costs for other components of the
treatment process, which can be confidently sized for the average waste-
water flow rate, rather than making allowances for peaking factors, etc.
54
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One particularly effective means of providing flow equalization, which
has been demonstrated by the food processing industry, is the use of
anaerobic lagoons as the first stage in the treatment sequence. If
properly designed, they can provide not only flow equalization, but
pretreatment of the waste and an effective means of disposing and
digesting biological sludge produced in the subsequent aerobic treatment
steps.
Sludge Disposal
The amount of sludge which will be generated and which will require
subsequent treatment and disposal should be an important consideration
in selecting a waste treatment process. At some of the plants visited,
sludge handling posed an enormous problem and constituted a major portion
of the annual operating cost. These were generally plants at which
voluminous amounts of sludge were produced, requiring haulage to an
ultimate disposal site some distance away.
Those plants for which sludge handling posed relatively few problems
were the extended aeration type, which had very low sludge yields, and
those which had on-site sludge treatment and disposal facilities.
As discussed under flow equalization, anaerobic lagoons provide an
effective means of treating and disposing of biological sludge, as well
as performing other functions.
In many cases, on-site sludge dewatering and disposal by means of drying
beds or spray irrigation also provides an effective and relatively
inexpensive means of handling partially stabilized sludges, such as
those from extended aeration plants.
In cases where insufficient land is available to permit on-site disposal
of sludges, one of the most important considerations in the selection of
a waste treatment process must be the amount of sludge generated by the
process and the cost of disposing of the same.
Nutrient Addition
A number of food processing wastewaters are known to be deficient in
either or both of the two nutrients, nitrogen and phosphorus, necessary
for effective biological treatment. In some cases, these nutrients were
added continuously at controlled rates based on calculated requirements
determined from chemical analysis of the raw and treated waste. However,
in other cases, nutrient addition amounted to the addition of "slugs" of
these chemicals to the waste on a weekly basis.
55
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The latter approach is not considered the optimum method of nutrient
addition. Since the cost of purchasing these chemicals is relatively
high, and the discharge of excessive amounts of nitrogen and phosphorus
is undesirable from a regulatory agency's point of view, every attempt
should be made to minimize the amount of supplementary nutrients required.
On the other hand, if the waste is in fact nutrient deficient, then it
is important to ensure that adequate amounts of nitrogen and phosphorus
are present at all times to permit the microorganisms to utilize the
soluble BOD effectively.
This can only be done by monitoring the BOD , nitrogen and phosphorus
concentrations of the raw and treated wastes on a regular basis, and
adjusting the rate of nutrient addition accordingly. This is particularly
important in industry sectors where a variety of commodities are processed
throughout the year, such as fruit and vegetable processing. As the
commodity changes so will wastewater characteristics and the nutrient
requirements.
Winter Operation
Cold weather operation of biological treatment systems poses two specific
problems; the first being a reduction in treatment efficiency due to
reduced biological activity, and the second being operational problems
of a mechanical nature associated with freezing conditions.
To ensure treatment plant performance conforms with regulatory agency
requirements on a year-round basis, it is essential that its design be
based on the most adverse conditions under which the plant will be
expected to perform. Considering the highly seasonal nature of most
food processing operations, the condition which should be used for design
purposes may be either peak hydraulic and organic loading or minimum
operating temperature (or both if the two occur concurrently). The plant
size required to achieve the desired effluent quality under each operating
condition should be determined and the larger size selected for design
purposes.
The sensitivity of the specific treatment process to temperature effects
should also be considered in the selection of a treatment system. In
general, suspended growth systems such as activated sludge, extended
aeration and oxidation ditches have been found to maintain superior performance
in cold weather to that of trickling filters and lagoons.
Specific mechanical problems associated with winter operation were identified
at virtually all plants visited, where treatment units were exposed to
the air. Problems such as the freezing of mechanical surface aerators,
trickling filter media and distribution equipment, and skimming mechanisms
in clarifiers were commonly reported.
56
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Some of the following design features and operating methods should be
considered to alleviate these problems and improve treatment efficiency
in cases where treatment plants are expected to perform under severe
climatic conditions:
1) Wherever feasible, treatment units should be enclosed to
minimize heat loss. While this is obviously not feasible
for large aeration basins, it is considered fundamental for
the successful winter operation of trickling filters and
clarifiers and is absolutely necessary for rotating biological
contactors.
2) The use of diffused air aeration equipment in place of mechanical
surface aerators can significantly reduce winter operating
problems in open aeration basins. The spray generated by surface
aerators has a tendency to freeze onto aerator vanes, shrouds,
and structural supports creating a heavy ice load which can
lead to mechanical and/or structural failure of the equipment.
This necessitates close supervision in winter months and
frequent ice removal from the equipment. Diffused air aeration
equipment, being totally submerged, is not susceptible to these
problems.
3) It is generally advisable to minimize the amount of wastewater
requiring treatment, by diverting any uncontaminated flows
away from the treatment facility for reuse or separate disposal.
There may, however, be some advantage in winter months to
directing hot uncontaminated wastewater flows, which normally
by-pass the treatment plant, through the facility, thereby
elevating its operating temperature. Care must be taken, however,
to ensure that this practice does not significantly reduce
detention time in the plant, which may further reduce treatment
efficiency.
Treatment Costs
The primary concern of any industry faced with the proposition of having
to install waste treatment facilities is the cost of constructing and
operating these facilities.
Unit treatment costs have been summarized for those plants for which
such data could be generated, and are presented in Figures 14 and 15 as
a function of plant size. As explained earlier, the unit treatment
costs are based on the total annual cost which includes the annual
operating cost of the plant, plus an 11% annual amortization allowance
on the capital cost.
As illustrated in Figures 14 and 15, considerable scatter exists in the
cost data. This scatter can be attributed to variations in wastewater
characteristics, treatment processes, and effluent qualities among the
plants considered, as well as other site specific variables such as
construction cost.
57
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'10
$I.OO
o
°Q
_l UJ
< h-
Z> <
•Z. LU
2 P1
< H-
ro
p-
O.IO
i^;_j_i_ 'i
PLANT A
PLANT B
PLANT E
PLANT F
PLANT H
PLANT I
PLANT J
•
D
»
O
•
&
A
PLANT K 0
i i ry • i I •; • •!' J* i . i
ae±
.1
O.OI
100
ooo
10 000
AVERAGE WASTEWATER FLOW
(m3/DAY)
FIGURE 14 - UNIT COST ($/mJ) OF BIOLOGICAL WASTEWATER
TREATMENT AT EIGHT FOOD PROCESSING PLANTS
58
-------
'10
H-
03
<
=5
<
<
O
LJ
UJ
*I.OO
10
O
CD
O>
0.10
100
PLANT A
PLANT B
PLANT E
PLANT F
PLANT H
PLANT I
PLANT J
PLANT K
D
O
A
0
-4e-
rrz*.:
I 000
10,000
AVERAGE WASTEWATER FLOW
(m3/DAY)
FIGURE 15 - UNIT COST ($/kg BODs REMOVED)
OF BIOLOGICAL WASTEWATER TREATMENT
AT EIGHT FOOD PROCESSING PLANTS
59
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Due to the number of variables associated with this cost data, no attempt
has been made to provide the reader with a rigorous cost-effectiveness
analysis of the alternative processes investigated. Rather, the data
will serve to illustrate the "order of magnitude" of these costs and the
trend of decreasing unit treatment costs with increasing plant size.
CONCLUSIONS
Biological waste treatment facilities at the twelve food processing
plants discussed in this paper illustrate that such systems can perform
effectively in northern climates if properly designed and operated.
Endeavours by senior management at these plants to meet their environmental
responsibilities have resulted in effective programs of wastewater
management.
Such wastewater management programs necessitate more than simply a
capital expenditure of funds for installation of an appropriate and
effective wastewater treatment system. An ongoing commitment must be
made to ensure that competent and trained operation of the process is
provided, and that in-plant measures are controlled so as to minimize
waste production and prevent treatment plant upsets. Only if this
commitment is genuinely made can cost-effective operation of a wastewater
treatment facility be assured.
60
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THE UTILIZATION OF CHEESE WHEY
FOR WINE PRODUCTION
by
G. M. Palmer* and R. F. Marquardt*
INTRODUCTION
In 1976 the United States Department of Agriculture (USDA)
reported production of nearly seventeen billion kilograms
(thirty-seven billion pounds) of whey in the United States
as by-products of the manufacture of cottage cheese and hard
cheeses such as cheddar, swiss, mozzarella, and jack. USDA
estimated that seventy percent of that whey was processed
into food, food ingredients, lactose or animal feed; but that
thirty percent was not utilized.
The latter unutilized portion became either an environmental
pollutant - being sprayed onto wasteland or dumped into rivers
or streams - or an added consumer cost being cycled to
municipal wastewater treatment systems for purification. It is
to the utilization of that currently unused portion of the
manufactured whey - sweet whey from the hard cheeses and acid
whey from cottage cheese - that this report addresses itself.
BACKGROUND
Much of the reason for the cited pollution from whey lies in the
economics of collecting it from small and/or isolated sources
for central manufacture into useful concentrated or dried
products by whey processors. To circumvent those economics and
to find a way to convert that whey into a useful and marketable
product at its source, Oregon State University (OSU) - working
under Environmental Protection Agency (EPA) Grant No. 803301 -
demonstrated the technical feasibility of fermenting supplemented
whey into an alcoholic beverage. That grant was entitled,
"Utilization of Cheese Whey for Wine Production."
Based on the successful completion of that work, Foremost Foods
Company was granted Project No. S-8038-63010 entitled, "A
Demonstration Project on the Utilization of Cheese Whey for
Wine Production."
*Foremost Foods Company, Research and Development Center,
Dublin, California
61
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OBJECTIVE
The objective of the Foremost project is to demonstrate the
technical and commercial feasibility of producing a consumer
acceptable, fermented beverage from whey. Understood, of
course, is a significant reduction in environmental pollution
and/or waste treatment costs.
RESULTS
To meet the objective, Foremost Foods Company, Research and
Development Center, developed processing to convert either
sweet or acid wheys into an alcoholic beverage giving little
or no hint in its flavor as to its origin in whey. A natural
fruit flavored beverage was developed from this base, and small
scale consumer testing demonstrated parity acceptance when
compared to a market leader in the fruit flavored wine class.
Preliminary process costs indicate the beverage can be
competitive in the market place. Materials balance studies
demonstrated that the waste, measured in terms of BOD, from
the fermentation process was significantly less than the BOD
which would have resulted from disposal of the whey without
fermentation.
It was demonstrated early that sweet whey or acid whey yielded
to processing in similar manner. Because the greater need for
whey utilization existed within the acid whey area, a major
portion of our efforts were directed to acid whey; although,
with nominal variation, they apply to sweet whey as well.
The processing from whey to a finished flavored product requires
1. Clarification of the whey
2. Deproteinization of the whey
3. Supplementation to a fermentable medium
4. Fermentation
5. Clarification of the ferment
6. Demineralization
7. Formulation
8. Polishing Filtration
9. Carbonation
62
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DISCUSSION
Processing
Let me discuss the process steps one by one, including our
experiences along the way.
Clarification of the whey is required to provide a whey that
is suitable for the selected deproteinization process. It is
accomplished readily with centrifugal clarifiers and separators
common to cheese manufacturing.
As a process step, it removes the fine cheese curds entrained
in the whey as it is drawn off the cheese vat and the butterfat
that is not entrapped in the cheese curd mass. This material
can be re-cycled in the cheese operation in various ways,
processed for other food use or routed to animal feeding
operations in its concentrated form.
Once clarified, the whey is deproteinized; not by heat or
chemical methods which denature the protein, but by ultra-
filtration which preserves the protein in its native form.
Ultrafiltration depends upon passing all but protein molecules
in the whey through a semi-permeable membrane to yield a water-
clear, deproteinized whey permeate as a fermentation base.
About ninety percent of the whey volume is passed as permeate
when the protein is concentrated to fifty percent on the dry
solids basis as the by-product. The whey protein concentrate
is suitable for many food applications or for animal feeding.
Several ultrafiltration systems, now commercial in various
sizes, are satisfactory for this processing step.
Supplementation of the whey permeate is accomplished simply by
adding a small amount of potassium meta-bisulfite as a yeast
protector and stimulant and twenty-two percent of dextrose as
a fermentable carbohydrate. Further supplementation is not
needed as the whey provides the essential nutrients for yeast
growth and fermentation.
Based upon the results of the early study by OSU, we elected to
utilize the yeast Saccharomyces cerevisiae sub sp. ellipsoideus,
Montrachet strain as our fermenting organism throughout the
study. This yeast, provided to the substrate in commercially
available active dry form, fermented the medium to a final
alcohol content of ten percent in seven to ten days at twenty-
one degrees Celsius (70 F) or ambient temperature.
The alcohol is derived by fermentation of the added dextrose,
the lactose present in the whey not being fermented by the
selected wine yeast. To ferment the lactose would have required
63
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fermentation by another type of yeast, followed by supplemen-
tation with dextrose and addition of the Montrachet yeast. A
lactose fermenting yeast currently is not available in a
commercial form, as is the Montrachet yeast, and would require
pure culture microbiology to maintain and bring up innocula
for the fermentation. To keep the processing simple and
readily manageable, we elected to not ferment the lactose, but
keep it intact to provide sweetening and enhance the flavor in
the final product.
In the initial stage of fermentation, we provided slow,
stirring agitation in stainless steel dairy processing tanks
equipped with propeller agitators of the sweep variety. This
provided only enough agitation to keep the yeast suspended
until active fermentation began. Once actively fermenting,
the yeast is kept in suspension by the active bubbling of
carbon dioxide generated by the yeast.
Clarification by centrifugal or filtration methods removes the
yeast bio-mass from the ferment and readies it for further
processing. We found that the preferred method was centrifugal
clarification, to remove the major portion of the cellular
material, followed by pressure filtration, using a diatomaceous
earth filter aid, to remove the remainder; resulting in a water-
clear, fermented beverage base.
The ferment - or beverage base - at this point in its manufac-
ture is predominantly salty in taste with a definite whey
flavor. Attempting to formulate a fruit flavored beverage
from this base led to poor results according to informal
sensory panels. It was resolved that the saltiness must be
removed to develop an acceptable beverage.
Two unit processes known to remove minerals from fluid streams
were evaluated; these are ion exchange and electrodialysis.
Ion exchange is well known in many industries as a demineral-
izing process; on the other hand, electrodialysis is not, but
it is the basis of manufacture of a series of modified whey
products widely used in the food, confection, and baking
industries and is a technology utilized by the whey industry.
Testing both processes, we looked at the advantages and dis-
advantages of demineralizing before or after fermentation. Ion
exchange before fermentation removed the saltiness but depleted
the medium of essential nutrients to the point of inhibiting
seriously the fermentation, whereas electrodialysis to about
seventy percent ash removal reduced the saltiness markedly
but did not inhibit fermentation. On the other hand, ion
exchange after fermentation removed not only the saltiness,
but the unpleasant whey flavors as well; whereas electrodialysis
64
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performed less well in removing the whey flavors.
Based on those results, we chose to demineralize after fermen-
tation using an ion exchange system comprised of a strong acid
cation exchanger and a weak base de-acidifier. Although not
tested, it is believed on the basis of other experience - that
activated carbon would effectively remove the whey flavors
if electrodialysis was utilized as a demineralizing method
instead of ion exchange
At this point in the process development, the flavor by mouth
attribute of the beverage base is predominantly alcohol, with
slight sweet and acid notes; a good base to accept flavoring.
We surveyed several versions of natural fruit flavors provided
by a number of flavor suppliers as compatible with our
beverage base. Comparing those flavors in our beverage base to
the fruit flavored commercial wines, we selected a black
currant flavor extract with other natural flavors for our
beverage. Working with the supplier, three adjustments to the
base flavor system were required before we were satisfied that
our target was met.
Formulation studies with the several versions of the selected
flavor system comprised variations in sweetening level, acid
level, flavor level and carbonation level.
The current formulation developed for acceptance panel testing
is characterized as follows:
Demineralized Ferment Base 75.9%
Invert Syrup 6.26%
Malic Acid 0.236%
Flavor Extract 2.42%
Water to Standardize 15.2%
This formulation, based on our acid whey fermented beverage base,
provided an acceptable approximation to the commercial target
wine in terms of the various flavor notes and overall balance
of flavor.
The next to final processing step is a polishing filtration.
This is accomplished using a microporous membrane filter
similar to those used for cold sterilization processing. As a
processing step, it removes the extremely fine particulates
from the wine, which cause haze and sediment, and gives a fine
65
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sparkle to the appearance of the beverage.
Finally, the beverage is chilled, carbonated to two volumes of
carbon dioxide and bottled ready for consumption.
Sensory Evaluation
This study was monitored throughout by extensive use of four
sensory evaluation technics:
1. Informal Panels
2. Descriptive Flavor Analysis (DFA)
3. Discriminatory Panels
4. Small Scale Acceptance Panels
The informal panels were used early in the study to screen
processing and flavoring systems and select the more feasible
alternatives.
Descriptive flavor analysis characterized the aroma and flavor
of the commercial wine and of experimental preparations, to
help adjust processing and formulation toward the target.
This technic uses trained panelists to quantify aroma and flavor
in terms of key components and develop flavor profiles which
describes the product under test. It proved very helpful in
identifying off-flavor constituents in the early part of the
study which aided their elimination by processing; and in
adjusting formulation variables to approximate the profile of
the target wine.
Discriminative panels, consisting of Research Center personnel,
assisted in adjusting formulation by rating both the
experimental products and the target wine in terms of too much
or too little of a flavor component.
Acceptance panels were used when other sensory evaluations
indicated that we had approximated the target wine in terms of
critical flavor constituents and balance. Results indicated
that in the eyes of the consumer as well as our in-house panels,
we had approximated closely the target wine flavoring balance -
although the flavors differed - by advising that the test and
target products were equally acceptable.
Economics and Waste
The major portion of this presentation has been devoted to
reviewing the development of processing procedures needed to
produce an acceptable product. Economic and waste abatement
66
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aspects were important portions of the study and were
considered throughout the product and process development.
Final cost and material balances are not complete at this
writing, but preliminary estimates - considered with those
projections resulting from the OSU study - indicate a process
and ingredient cost of fifty to sixty cents a fifth of a
gallon. Material balances show that the BOD of waste streams
from the process can be less than twenty-five percent of the
BOD of the whey itself.
CONCLUSION
At this writing, a large scale consumer evaluation in the form
of acceptance panels is being completed in east coast, midwest,
and west coast locations to answer the question of commercial
parity in the acceptance of the fermented whey beverage as
against a market leader in the flavored wine class. Those
results, together with the results reported or indicated here,
will bear the proof of successfully meeting the challenge
of converting cheese whey and cottage cheese whey into an
alcoholic beverage acceptable in the market places of the
United States.
Collectively, they will provide the cheesemaker an interesting
and economic alternative to whey disposal as currently
practiced, and provide the means to reduce environmental
pollution due to whey.
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TREATMENT OF CAUSTIC PIMIENTO WASTEWATER
by
JL 4.4.
T.M. Furlow and P. Chen
FOREWARD
The caustic wastewater treatment system discussed here was constructed over
a three month period and started receiving wastewater in early August, 1977,
Due to the light production and other construction conditions during 1977,
this system was not fully evaluated during 1977.
BACKGROUND
Nabisco, Incorporated operates a food processing plant in Woodbury, Georgia
approximately fifty-five miles southwest of Atlanta. This facility produces
roasted peanuts, peanut butter and packaged dates year round, and canned
pimientos during August, September and October of each year. Wastewater
flows average around 380 M^/day (0.1 mgd) except during pimiento season when
average flows increase sharply to 2270 M^/day (0.6 mgd). Characteristics of
the raw wastewater during 1976 are shown in Table 1. The pimiento season
wastewater is much stronger than the non-pimiento season wastewater, and is
produced in much greater quantities. When Nabisco considered separate waste-
water treatment facilities in 1973, several processes were examined. The
final alternatives were activated sludge and overland flow (land application).
Due to the large seasonal variation in both quantity and strength of the
wastewater, and the availability of sufficient land, overland flow was
selected. A fifty acre site was prepared and placed into operation. This
system is shown in Figure 1. All wastewater was screened before being pumped
onto the spray field. The system functioned well until 1975 when the runoff
from the spray field started to increase in strength. Much of the grass
died, and waterlogging of the soil was observed. By the end of the season
it was obvious that corrective measures were necessary.
DEFINITION OF PROBLEM
Prior to 1975, all pimientos were peeled by a fire roasting process fueled by
natural gas. Interruptions in the supply of natural gas forced Nabisco to
institute caustic peeling of pimientos midway through the 1975 season.
In February of 1976, Jordan, Jones and Goulding, Inc. was retained to study
the system and to determine the cause of the previous season's difficulties.
A ten month study program was initiated which included an in-depth sampling
program during the 1976 pimiento season. The precise problems were found to
* Jordan, Jones and Goulding, Inc., Atlanta, Georgia
** Nabisco, Inc., East Hanover, New Jersey
68
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TABLE 1. AVERAGE CHARACTERISTICS OF RAW WASTEWATER
Characteristic
VO
Suspended Solids
Total Volatile Suspended Solids
PH
Flow
Non-Pimiento Season
1600 mg/1
170 mg/1
140 mg/1
9.4
Pimiento Season
3450 mg/1
540 mg/1
480 mg/1
11.5
380 M3/day (0.1 mgd) 2270 M3/day (0.6 mgd)
-------
PUMP STATION
1
SCREENS
SPRAY FIELD
PUMP STATION
SPRAY FIELD
4 1 SEQUILIZATION
BASIN
FLOW
MEASURING
Figure I. Treatment facilities
prior to 1977.
70
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be anaerobic conditions. The waterlogging of the soil and the reduced infil-
trative capacity were found to be directly related causes of the anaerobic
conditions. Two Sodium Absorption Ratio (SAR) tests run on caustic waste-
water samples gave results of 43 and 274. This indicated probable defloccu-
lation of the clay soil and sealing of the soil surface. Infiltration tests
revealed that the infiltration rate in irrigated areas had been reduced to
zero; the infiltration rate in buffer zones was measured to be 1.9 centi-
meters per hour (0.75 inches per hour). It was also noted that the high
solids loading was physically clogging the soil pores. The BOD,, loading rate
to the spray field increased to over 650 kg/hectare/day (580 Ibs/acre/day) at
an application rate of 2.16 cm/day (0.85 inches per day). The literature
reports success up to 112 kg/hectare/day (100 pounds per acre per day) of
BODij loading. Wastewater which had not been retained in the flow equalization
basin was often irrigated directly onto the spray field. The pH of this
wastewater was usually in the range between 12.0 and 12.5, and damaged the
grass in several areas. Wastewater which had been retained in the flow equa-
lization basin had a pH of approximately 5.0. The detention time in the flow
equalization basin was only 12 to 24 hours, but very rapid pH changes were
evident. In an attempt to duplicate the pH change, raw wastewater samples
were collected and seeded with varying volumes of pond effluent. This mixture
was then adjusted to 11.5 with NaOH. Within one hour, the pH of the mixture
was 5.1. The cause of this rapid change has been attributed to aerobic
fermentation, although acid forming bacteria were likely present in the sludge
in the bottom of the pond.
The study concluded that the problems encountered during the 1975 and 1976
pimiento seasons were caused not by one factor, but by a combination of the
factors discussed above. It was further concluded that wastewater with the
present caustic characteristics was not ammenable to treatment by the
existing land application system.
DEVELOPMENT OF TREATMENT ALTERNATIVES
After determining that caustic wastewater was not suitable for treatment by
land application, several courses of action were available.
(1) Change the characteristics of the wastewater by process changes;
(2) Abandon the existing overland flow system, and develop a new
treatment process;
(3) Segregate the wastewater originating in the caustic peeling process,
and treat it independently of the rest of the wastewater.
The first did not prove feasible because management determined that NaOH was
the only practical peeling agent. The second course of action was feasible
but, because of the large existing capital outlay,was more expensive than the
third. The wastewater originating in the caustic peeling operation could
be easily segregated, and constituted less than 10% of the total flow. It
was therefore determined that the third alternative would be selected.
Before treatment processes for the caustic wastewater could be formulated,
it was necessary to characterize this particular portion of the wastewater
stream. Sampling and flow measurement results are presented in Table 2.
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TABLE 2. CHARACTER OF CAUSTIC PIMIENTO WASTEWATER
BOD5 20,000 mg/l
COD 35,000 mg/1
Suspended Solids 16,000 mg/1
Total Volatile Suspended Solids 13,500 mg/1
pH 12
Flow 245 M3/day (0.065 mgd)
-------
The exceptionally high BOD_ and COD values indicated that an aerobic treatment
system would require a high energy input. For this reason, initial considera-
tions were directed at non-aerobic processes. One alternative was to use an-
aerobic ponds. These could not be located close to the production facilities.
Tank trucks could be used to transport 246 M^/day (0.065 mgd) of caustic
wastewater to a suitable site during pimiento season. Another alternative
was to use an activated sludge process. This alternative, however, was not
feasible due to the seasonal production of the caustic wastewater. Finally,
consideration was redirected toward aerobic processes despite the high energy
requirements. Aerated ponds with long detention times appeared promising
since suitable land was available. Recent work in North Carolina (1)
indicated that the energy input could be minimi zed if aerobic/anaerobic
ponds were utilized. In the several systems in operation in North Carolina,
floating aerators with special deflector plates aerate only the top four
or five feet, thus creating sharp, distinctive aerobic and anaerobic layers.
The aerobic surface layer retards odors and allows use of the anaerobic
process in areas where anaerobic ponds might otherwise be unacceptable.
Preliminary cost estimates were prepared and the workability of each alter-
native was evaluated. The aerobic/anaerobic pond alternative was selected.
The capital cost of the anaerobic pond system was considerably less, but it
was felt that transporting the wastewater by truck on a continuous basis was
not a workable solution.
SELECTED SYSTEM
The aerobic/anaerobic system selected consists of three aerated ponds followed
by a package sand filter, flow measurement, and a back up pH adjustment system,
as shown in Figure 2.
The first pond is 15 feet deep and is designed to provide an aerobic layer
approximately 1.2 to 1.5 meters (4 to 5 feet) deep, with the lower 3.0 to
3.4 meters (10 to 11 feet) being anaerobic. The detention time is 52 days
at design flow. Table 3 gives detailed information on all three ponds.
The second pond is a complete mix basin with a 10 day detention time. Its
primary purpose is to insure that all of the wastewater is aerobic before
it is discharged into pond three.
The third pond serves as a holding pond and allows the wastewater to be
discharged over the entire year. Two submersible pumps controlled by time
clocks regulate the discharge rate from this pond. The floating aerators
are intended to be used only when the water depth in this pond is greater
than six feet.
The discharge from pond three is pumped into a package sand filter to insure
that suspended solids from the pond are low enough to comply with EPA re-
quirements. Alum can be added as a coagulant prior to filtration when
necessary.
A backup pH adjustment system is also included which can adjust pH at either
the influent to pond one, or the effluent from pond three.
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SCREENS
PUMP STATION
STAND BY P H
'ADJUSTMENT
AEROBIC
ANAEROBIC
POND SYSTEM
STAND BY pH
"ADJUSTMENT
FILTER
FLOW
MEASURING
Figure 2.
Co ustic waste water
t reatment facilities.
74
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TABLE 3. POND DESIGN INFORMATION
Expected BOD,. Depth Volume Detention Time
Pond Removal (%) Meters (feet) M3(ft3) Days Pond Type
_ —
1 80 4.6 (15) 12,800 (452,000) 52 Aerobic/Anaerobic
2 50 2.4 (8) 2,460 ( 87,000) 10 Aerobic-Complete Mix
3 80 0-4.6 (0-15) 26,000 (919,000) One Season Aerobic-Holding Basin
-------
Following the sand filter, the discharge is mixed with any runoff from the
spray field. Flow is measured in a Parshall Flume prior to its discharge
into surface waters.
CONSTRUCTION AND INITIAL OPERATION
Construction on the caustic wastewater treatment facilities started in May
1977. On the first day of the 1977 pimiento season, August 4th, the first
pond was placed into service. In order to check the operation of the floating
aerators, the basins were partially filled with water. Thus, test results
from the 1977 season are not totally representative of treatment levels the
system can produce. BODc removal did exceed 80% in the first pond, but a
detailed evaluation of the remainder of the system was not possible during
the 1977 season. It is anticipated that an in-depth study program will be
conducted during the 1978 season to further evaluate the operation of this
system.
REFERENCES
1. Humerick, F. J., Personal conversations
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OVERLAND FLOW TREATMENT OF DUCK PROCESSING
WASTEWATER IN A COLD CLIMATE
by
Lloyd H. Ketchum, Jr.*
INTRODUCTION
Highly skilled personnel for design and construction as well as operation of
wastewater treatment plants for small slaughterhouses and poultry processing
plants is generally not available. These small slaughtering and processing
operations account for a small fraction of the total slaughter, however,
they do nevertheless make up a very large fraction of the total sites. These
small plants are generally located in rural areas close to the growing oper-
ations and feed lots.
There is a need, therefore, to develop treatment facilities which are easy
to design, simple and inexpensive to construct, and which can produce high
quality effluents using relatively unskilled operators. In general, land is
available since these plants are located in rural areas. Being located in
scattered rural areas, however, wastewaters are often discharged into small
streams and rivers or directly into the ground water. These wastes, if im-
properly treated, can cause serious degradation in water quality in these
scattered rural areas.
The objectives of the project discussed herein are summarized as follows:
.To demonstrate the operation of an inexpensive wastewater treatment
facility which will meet the 1983 National discharge limitations.
.To evaluate the use of spray runoff irrigation in a cold climate.
.To evaluate the effectiveness of batch chemical treatment directly in
a lagoon for phosphate and suspended solids removal (including algae)
and disinfection.
.To develop basis of design for the proposed treatment system, and to
present these design details sufficiently clear to allow their use
by slaughterhouse operators with little technical assistance.
.To present estimates of costs for treatment to allow economic compari-
son of this system to.others capable of treating these type wastes.
The project is currently in progress and none of these objectives have been
completed. Reported herein, however, are details of the design and construc-
*Assistant Professor of Civil Engineering, University of Notre Dame,
Notre Dame, Indiana 46556
77
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tion of these facilities and winter operation of the spray runoff irrigation
plot.
The project is being conducted at Culver Duck Farm, Inc. near Middlebury,
Indiana. This is a completely new processing plant. Processing was begun
on November 10, 1977 at a rate of 200 ducks per day. The current rate is
about 4000 ducks per week, the maximum which can be grown indoors during
winter periods. To date, approximately 70,000 ducks have been processed.
The plant has been designed to minimize water use, and includes the use of
a vacuum evisceration system. Wastewater volumes have been estimated at
23 L/duck (6 gal/duck). Current water use is unknown since the meter has
not yet been installed. Consumption appears to be considerably higher than
this estimate, primarily because production is much lower than the design
capacity, which results in higher water use per duck, and the operators have
concentrated on the processing operation and have not yet devoted sufficient
attention to water usage. The overall effect is discharge of relatively
large volumes of weak wastewaters.
WASTEWATER TREATMENT SYSTEM
Table 1 gives the basis of design and a schematic diagram of the wastewater
treatment system is shown in Figure 1. A fine screen, Rotostrainer, is used
to remove pin feathers, offal and other solids which may be present in the
water prior to discharge to the sewer. A gravity grease separator follows
the fine screen. However, heavy grease loads are not experienced because
of the dry evisceration and the effectivenss of the fine screen. These
solids are picked up by the vacuum system and conveyed to holding containers
where they are picked up by a rendering service.
Following this preliminary treatment in the plant, the wastewater flows to
the pump manhole where it flows either into the storage lagoon or is pumped
directly to the spray runoff irrigation plot. During periods of processing,
the pumps may be operated to apply raw wastewater directly to the spray run-
off irrigation plots. During periods when no processing occurs the pumps
may be operated to discharge wastewater which has undergone some stabiliza-
tion during storage in the storage lagoon. This system has been designed to
allow the flexibility of either operation- Both will be utilized during
various operating modes throughout this study.
Two spray runoff irrigation, or overland flow, plots are used to allow two
modes of operation under parallel conditions. Each is 20 m wide by 80 m
long (65 ft. by 260 ft.), or 0.16 hectares (0.39 acres) in area. Loading
rates and cycle conditions will be varied during the study. Current opera-
tion results in applying wastewaters ten hours per day, five days per week
at a rate of 7.6 cm per week (3 inches/week).
Traditional spray runoff irrigation methods are only suited for soils with
low permeabilities. This low permeability reduces contamination of ground
waters and allows for additional treatment either in a lagoon as used in
this study, or by recycle back to the plot during periods of low quality.
78
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TABLE 1: DESIGN BASIS
PART A
Process
Production
Operating Days
Live Weight
Waste Volume
3000 ducks/operating day
winter 2 d/week
summer 3 to 4 d/week
6.4 Ibs/duck
2.9 kg/duck
6 gal/duck
23 L/duck
PART B
Waste Treatment Facilities
Storage Lagoon
Overland Flow Plots
Batch Treatment Lagoon
0.46 MG
1740 m3
2 plots
65' x 260' 0.388 acres
20 m x 79 m 0.157 hectares
4 percent slope
applications 3 in/week
7.6 cm/week
0.13 MG
490 m3
4 weeks storage*
*Based on summer production and 50% evapotranspiration loss
on overland flow plot.
79
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WATER
SUPPLY
VACUUM
PROCESS
PLANT
VACUUM
ROTOSTR&INER
GREASE TRAP
STORAGE
GRINDER
PUMPS
PUMP
MANHOLE
OVERLAND FLOW
BATCH TREATMENT INFILTRATION
FIGURE 1: Wastewater Treatment System Schematic
80
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Therefore, only effluents meeting effluent limitations are discharged into
receiving streams or ground waters. In areas where only permeable soils
exist, traditional spray runoff irrigation treatment is not possible. This
study addressed this problem, and developed a method of treating wastewaters
by spray runoff irrigation techniques on relatively permeable soils. The
Culver Duck Farm site, according to U.S. Soil Conservation Service data, is
located on a sandy loam (Oshtemo Series) with a permeability of 5 to 15 cm/h
(2 to 6 inches/hour) which is much greater than that of the clays normally
used for spray runoff irrigation.
To eliminate infiltration of the wastewater into the ground water at this
site, a bentonite seal was constructed six inches below the top soil which
was than carefully graded to provide a four percent slope. This seal essen-
tially eliminates infiltration into the ground water, and all applied waste-
water, not lost by evapotranspiration, reaches the foot of the plot. Figure
2 shows details of the construction of this spray runoff irrigation plot.
The batch treatment lagoon serves two primary functions. First, all ef-
fluents from the spray runoff irrigation site are collected until the lagoon
is full. Laboratory jar test procedures are then completed to determine
needed chemical dosage for phosphorous and suspended solids reduction.
Using a floating mechanical aerator to provide mixing, alum is sprayed into
the mixing lagoon followed by a hypochlorate solution for disinfection. Af-
ter an appropriate period of mixing, the aerator is shut off and the solids
allowed to settle. After appropriate analyses are conducted on the settled
lagoon supernatant, and these analyses indicate an effluent of sufficiently
high quality, the contents of the lagoon are discharged to the infiltration
lagoon. If the lagoon supernatant has not met discharge limitations, its
contents can than be mixed and additional treatment provided. The second
function of this lagoon is to collect wastewater which received inadequate
treatment during spray runoff irrigation. This may occur during periods of
high rainfalls or during application under other unfavorable conditions.
These low quality effluents can than be returned to the storage lagoon for
treatment under more favorable conditions, thus preventing discharge of poor
quality effluents.
MONITORING
Flow rates are monitored at three locations in the system and change in la-
goon water volumes allows calculation of average flows at two other points.
First, water pumped from the plant well water supply is measured to allow
determination of water consumption which can be compared to the number and
live weights of ducks processed. Magnetic Flosensors available from Cole-
Parmer Instrument Co. equipped with a totalizer and flow rate indicator are
used in the grinder pump discharge lines to indicate flow rates to each of
the two spray runoff irrigation plots. Effluents from these plots are
measured in a weir box using a 22-1/2° V-notch weir for low flows during
normal conditions and a rectangular weir for high flows during rainfall
periods. Both lagoons have been measured to allow determination of liquid
volumes between any depth, thus indicating average flows for any period of
time during which these depths are changing.
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/-DISTRIBUTOR PIPE
-------
Wastewater analyses are conducted generally according to procedures outlined
in Standard Methods and include the following: 5-day BOD, TOC, pH, suspended
solids, ammonia, nitrate plus nitrite, Kjeldahl nitrogen, and ortho and total
phosphate. These are generally taken at the influent and effluent end of
each unit. In addition, temperature, dissolved oxygen, COD, oil and grease,
settleable solids and fecal colifonns will also occasionally be determined.
TEMPORARY FIRST WINTER OPERATION
During the construction and start up phases of the processing plant, a time
when we were also trying to complete construction of the wastewater treatment
facilities, considerable difficulties were encountered which demanded the at-
tention of the personnel assigned to both of these tasks. This resulted in
delays in completion of the wastewater treatment system. These delays ex-
tended into an unusually severe winter where record snowfalls occurred. By
the end of December, we had already almost reached the average annual snow-
fall of 67 inches. An additional 86 inches fell in January contributing to
a new record annual snowfall.
The control building, used mainly to house the flow measurement equipment,
was only partially completed before winter, thus preventing installation of
the flow measuring equipment. The underground piping from the pump manhole
to the spray runoff irrigation distributor pipe was placed in the ditches.
However, before these could be backfilled the backfill material and the soil
in the ditch had frozen preventing completion of the backfill operation.
Several methods to allow temporary winter operation were considered. The
method finally selected and installed which allowed for the operation re-
ported herein is described as follows:
.A single grinder pump is operated continuously with discharge through
one of the partially buried pipes. This continuous flow prevents
freezing of the exposed pipe.
.A temporary pipe is connected to the partially buried pipe and runs
above ground to and past the distributor pipe into a lagoon system
used to treat wastewaters from the duck growing operation.
.A three-valve connection is made between the temporary above ground
pipe and the inlet to the distributor pipe of one plot. These valves
are arranged to allow restricted flow at all times through one valve
into the lagoon. During periods of spray runoff irrigation, a second
valve is fully opened to direct flow into the distributor pipe. The
valve used to restrict flow to the lagoon is adjusted to provide the
desired application rate to the spray runoff irrigation plot. At the
conclusion of an irrigation period, the second valve is closed and a
third valve opened which drains the distributor pipe and prevents its
freezing.
Influent flow rates are determined by recording the time required to fill a
known volume from each orifice in the distributor pipe. The effluent from
the spray runoff irrigation plot is allowed to overflow the dike at the foot
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of the plot where it then passes through an earthen ditch and over a tempo-
rary 45° V-notch weir. Effluent flow rates are thus determined by measuring
the depth of flow over the V-notch weir.
Wastewaters were first applied on February 22, 1978. At this time, there
was about 23 cm (9 inches) of relatively densely packed snow covering the
site. At least two weeks passed before overflow of the dike occurred at the
foot of the plot. Wastewater was applied as indicated above resulting in an
application of approximately 7.6 cm per week (3 inches per week). The snow
had been removed from the area near the distributor pipe. Applied wastewater
appeared to flow down the slope under the snow and accumulate at the foot of
the plot behind the dike. At that point it froze. Later, as melting oc-
curred and additional water was applied, it overflowed the dike. Snow was
gradually lost from the plot until only about one half the area was covered
with a layer of ice. The idle plot, adjacent to the operating plot appeared
to behave essentially the same. Snow loss, flow over the dike and ice for-
mation all appeared to be similar.
One interesting observation was the grass which appeared to be a healthy
green in the areas not covered with snow or ice.
RESULTS
Occasional grab samples were taken from the influent and effluent of the
spray runoff irrigation site after the first two weeks of operations. In
general, two influent conditions occurs. One when pumping occurs during
processing which results in raw wastewater being applied to the plot, and
the other when no processing is taking place which results in water from the
storage lagoon being pumped to the plot. In the first case, the influent
wastewaters tended to be relatively strong with 5-day BOD's greater than 100
mg/L being common. In the second case, these wastewaters were relatively
weak having 5-day BOD's between one-third and one-half this level. This is
due partially to the stabilization which takes place in the lagoon but also
due to dilution during the early phases of plant start up when only a few
ducks were being processed using full process water flows.
The grab sample effluents from the plot were relatively weak showing 5-day
BOD's of 5 to 10 mg/L. Dilution from melting snow undoubtly contributed to
these low values.
Two detailed analyses of the influent and effluent of the spray runoff irri-
gation site were completed. One of these was taken from samples collected
March 21, 1978 which was during a duck processing period, therefore, a period
of application of raw wastewater. The other, March 22, 1978, was conducted
during a day when no processing took place and wastewater from the storage
lagoon was being treated. The results of these analyses are shown in Table
2. These data are taken from flow-weighted composite samples collected
during the period of spray runoff irrigation pumping.
A mass balance, based on the average influent and effluent flow rates during
the sample periods, and the composite analyses of these waters is shown in
84
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TABLE 2: WASTEWATER CHARACTERISTICS
Overland Flow Plot
Influent Effluent
March 21, 1978 Sample
5-day BOD, mg/L
COD, mg/L
NO + NO , mg/L as N
NH , mg/L as N
Total Kjeldahl nitrogen, mg/L as N
Orthophosphate, mg/L as P
Total phosphate, mg/L as P
March 22, 1978 Sample
5-day BOD, mg/L
COD, mg/L
NO + NO , mg/L as N
NH3, mg/L as N
Total Kjeldahl nitrogen, mg/L as N
Orthophosphate, mg/L as P
Total phosphate, mg/L as P
PROCESSING
170
250
0
4
33
2.3
2.6
NO PROCESSING
93
230
0
3
23
0.3
0.6
DAY
7
80
0.01
4
10
0.7
0.6
DAY
24
45
0
3
3
1.2
1.3
in Table 3. In general, it appears stabilization of organic matter is taking
place and nitrogen removal is occurring in spite of the ice and snow cover and
the relatively low temperatures. Several other grab samples taken during the
two weeks preceding this study also indicated stabilization of organics and
nitrogen removal were taking place. Table 4 has been included to indicate
weather conditions during the period of overland flow treatment. Applica-
tion first began on February 22, 1978, and these detailed analyses were
taken a month later on March 21 and 22, 1978. Due to the ice formation
during the previous 30 days of applications of wastewater, a considerable
amount of snow and ice remained on the plot and significant amount of melting
85
-------
TABLE 3: MASS BALANCE
PROCESSING DAY
March 21, 1978 Sample
Average Flow During Sample
Period L/s
5-day BOD, mg/s
COD, mg/s
NH , mg/s
Total Kjeldahl nitrogen, mg/s
Orthophosphate, mg/s
Total phosphate, mg/s
March 22, 1978 Sample
Average Flow During Sample
Period L/s
5-day BOD, mg/s
COD, mg/s
NH , mg/s
Total Kjeldahl nitrogen, mg/s
Orthophosphate, mg/s
Total phosphate, mg/s
Influent
0.42
71
105
1.7
14
1.0
1.1
NO
0.83
77
191
2.5
19
0.2
0.5
Effluent
0.62
4
50
2.5
6
0.4
0.4
PROCESSING
1.92
46
86
5.8
6
2.3
2.5
% Reduction
increased
94
52
increased
57
60
64
DAY
increased
40
55
increased
68
increased
increased
was occurring, as can be seen by the effluent flow rates.
DISCUSSION
To date, the findings have been very promising. The use of the bentonite
layer below the top soil in the overland flow plot extends the possible ap-
plication of overland flow treatment to all areas of the country regardless
of soil conditions. The bentonite layer further eliminates infiltration of
applied wastewater into the ground water during treatment. Essentially all
water applied and not loss through evapotranspiration can be collected at
the foot of the hill for additional treatment or retreatment if it does not
86
-------
TABLE 4: WEATHER CONDITIONS*
Date
Feb. 22, 1978
23
24
25
26
27
28
Mar. 1, 1978
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
Average
Temp., °F
14
20
28
32
18
21
27
18
13
21
15
11
26
24
24
19
28
35
36
35
38
35
30
25
28
34
37
40
44
Precipitation, inches
Water Equivalent,
0
0.07
0
0.07
0.06
T
0
0
0.07
0.12
0.01
0
0
0
0
0
0
0.20
T
0.36
0.45
T
T
T
0
0.75
0.03
T
0
Snow
0
1.0
0
1.2
1.1
T
0
0
1.0
3.1
0.5
0
0
0
0
0
0
T
0
0
0.4
0.1
T
T
0
0
0
0
0
Snow on Ground
at 7 a.m., inches
17
16
17
15
16
16
15
14
13
16
15
15
15
13
12
12
11
9
8
7
6
4
4
3
3
2
1
T
T
*Based on records collected at South Bend, Indiana,National Weather
Service Office, Michiana Regional Airport, which is located about
30 miles due west of the test site.
meet discharges limitations; thus, only fully treated wastes are discharged
to receiving water or ground surfaces for infiltration into the ground
waters.
The few operating results we currently have under winter conditions also ap-
pear favorable. Stabilization of organics and nitrogen removal both appeared
to be occurring under cold climate conditions. Thus, overland flow treat-
ment can be an alternative considered not only for areas of any soil condi-
tion, but even in areas of cold climate.
87
-------
Additional phases of the overland flow study will be directed toward develop-
ment of more favorable operating conditions during these winter periods. One
approach we plan to consider is elimination of the use of storage before
overland flow treatment. Thus, we will apply the raw (warm) wastewater
during processing operations. In our case, this is typically during two
consecutive 10-hour day periods each week during winter operations. For
other systems when operation is more nearly continuous, we would propose
several parallel operations sequenced to provide similar treatment. The
warm raw wastewaters would be applied to the overland flow plot and continu-
ally recycled from a small lagoon at the foot of the plot to the top until a
suitable effluent was obtained. Other operating and loading procedures will
also be considered to attempt to develop operating procedures to allow winter
operation, or to determine under what conditions winter operation must be
discontinued and storage provided.
ACKNOWLEDGMENT
This project has been financed in part with Federal funds from the Environ-
mental Protection Agency under grant number R-804677. The contents do not
necessarily reflect the views and policy of the Environmental Protection
Agency, nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.
88
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ECONOMICS OF STARCH AND ANIMAL FEED
PRODUCTION FROM CULL POTATOES*
by
**
J. R. Rosenau, L. F. Whitney, and J. R. Haight
ABSTRACT
A finalized process for production of starch and animal feed pulp, high pro-
tein powder, and juice concentrate from cull potatoes is presented. Economic
evaluations are presented for the process and an option applicable if the
plant is located near a ruminant feedlot.
INTRODUCTION
Processes for upgrading cull potatoes to starch and animal feed by-products
have been discussed by the authors at previous symposia (1) (2). By addi-
tional laboratory (3) and pilot plant experience (A), these processes have
been tuned to the finalized processes shown in Figs.l and 2 and briefly out-
lined below. An economic evaluation follows which suggests that reasonable
returns on investment are possible even under recent dramatic price increases
in fuel and equipment (M & S Index of 518 as opposed to only 344 in 1973) (5).
STARCH PROCESSING
As shown in Fig. 1, cull potatoes are washed with recycled water and ground
with 250 ppm SO in a hammer mill using a screen with 1.6 mm (1/16 inch)
openings. The slurry is screened in a two-stage system with recycled juice.
Most of the cellulosic material (pulp) remains above the 140 mesh screen while
juice and starch pass through. The pulp is dewatered in a screwpress and
dried in a continuous tray drier using waste heat from the juice processing
system.
The starch/juice slurry is pumped into an elutriating-type liquid cyclone
which has an extra inlet near the underflow outlet. Starch is spun to the
underflow and the overflow juice recycled to the screening system. Excess
juice is forwarded to the regenerative plate heat exchanger shown in Fig. 2.
*This investigation has been supported by the U. S. Environmental Protection
Agency (Grant No. R-803712-03-0), Agway, Inc., the Main Potato Commission,
and the University of Massachusetts.
**Department of Food and Agricultural Engineering, University of Massachusetts,
Amherst, MA 01003.
89
-------
WASHED POTATOES
GRINDER |
| SIEVE
WET PULP
PRESS )
JUICE 8 STARCH
[ TANK
PUMP
ELUT
CYCLONE
MECHANICAL
DEFOAMER
1
CAKE
CONTINUOUS
TRAY DRIER
I
PULP
r-Y
1
IP) IMP 1 &
t wlWI" 1 *•
CYCLONE
PUMP «
BASKET CENTRIFUGE]
CAKE
j DRIER j
I
STARCH
Figure 1. Starch processing flowchart.
90
-------
JUICE (3.9% SOUPS)
IO°C
PLATE HEAT EXCHANGER \
»9°C
60°C
INFUSERj
I2I°C
PLATE HEAT EXCHANGER^
66°C
| NOZZLE CENTRIFUGE
SLUDGE, 20% SOLIDS
| SPRAY DRIER |
I
PROTEIN POWDER
(70% CRUDE PROTEIN, D.B.)
:THEAT EXCHANGE FLUID
(TO a FROM PULP DRIERh
REVERSE
OSMOSIS
EVAPORATOR
T
CONG. JUICE
(65% SOLIDS, 43%
CRUDE PROTEIN, O.B.)
Figure 2. Juice processing flowchart.
-------
TABLE 1. ESTIMATED FIXED CAPITAL INVESTMENT FOR
PROCESSING 500 TONS OF CULL POTATOES
PER 20-HOUR DAY
ITEM
COST. $
COST, $
Flume pump
Washer pump
Washer
Destoner
Mill
Metering feeder for Na^S-O
Sieve system
Mechanical defoamer
Press
Pulp drier
Pulp mill
Pulp air conv. system
Pulp bins (2)
Cyclone pumps (5)
Elut. cyclones (8)
Thick, cyclone pumps (5)
Thick, cyclones (4)
Pump, centrif. to cyclones
Basket centrif.
Starch drier
Starch mill
Starch conv. system
Starch screen
Plate heat exchanger
steam injector
Boiler (12000 Ib/hr)
Fuel tank
Nozzle centrif.
Spray drier
Rev. osmosis modules
Rev. osmosis feed pump
Rev. osmosis cir. pumps (3)
Evaporator
Concentrate pumps (2)
Concentrate tank
Balance tanks (4)
Protein bin
Truck scale
5000
3000
20000
20000
50000
4000
60000
24700
50000
60000
10000
5300
10000
15000
5600
15000
800
1000
98800
16800
10000
5500
6000
20000
2000
25400
16900
100000
23700
87000
15800
12000
118600
8000
16900
25200
5000
9500
I. Total Process Equipment
II. Installation (30% of I)
982500
294800
92
-------
TABLE 1 (continued)
ITEM
III. Piping, Wiring, and Control Systems
(40% of I and II)
IV. Engineering and Contractors' Fees
(20% of I, II, and III)
V. Contingencies (15% of I, II, III)
VI. Trucks
Concentrate truck
Protein truck
Pickup truck
VII. Land
Office
Incoming storage
Process area
Warehouse
VIII. Buildings total
COST, $
70000
40000
7000
35000
63800
168000
60000
COST, $
510900
357600
268200
117000
40000
IX.
TOTAL FIXED COSTS
93
-------
Starch leaving the underflow cyclone outlet is thickened with a second liquid
cyclone before passing to an automatic batch basket centrifuge for washing and
dewatering. Liquid from the basket centrifuge as well as that removed by the
thickening cyclone pass into the elutriation inlet of the first cyclone to
separate "brown starch" from the starch. Attempts to eliminate the thickening
cyclone or to add an elutraition inlet to it have not proven as successful as
the scheme shown. Drying of the starch cake leaving the centrifuge should be
done in a flash drier for maximum whiteness. Hunter L values of 92 (which
should be sufficiently white for most purposes) have been consistently achieved
in later pilot plant runs even with very low starch content potatoes and drying
in a tray drier at HOC. Proper washing of raw potatoes is also important
for maximum whiteness; an industrial washer, coupled with finer control of
the elutriation flow rates, should improve whiteness even further.
JUICE PROCESSING
As shown in Fig. 2, juice is heated to 60C in a plate-type regenerative heater
and then to 121C by steam injection. This coagulates about 35% of the crude
juice protein so that it can be removed as a 20% solids (70% protein, d.b.)
sludge by a nozzle-type disk centrifuge and dried in a spray drier. The re-
maining deproteinated juice (still at 43% crude protein, d.b.) is concentrated
by reverse osmosis to 10% solids and by multiple-stage evaporation to 65%
solids. It is stable in this condition and should be useful as a molasses
substitute for ruminant feeding.
ECONOMIC EVALUATION
Estimated capital costs based on references (5)-(9), personal estimates, and
telephone calls to selected suppliers are shown in Table 1. Table 2 shows
annual costs and returns assuming the plant is run for 200 days for 20 hours
per day. Also shown is the first-year return on investment (R.O.I.) at 40.1%.
LIVESTOCK OPTION
If the processing center is located near a ruminant feedlot of at least 2500
dairy cows or its equivalent (or vice versa) the pulp and concentrated juice
from the reverse osmosis system can be used directly without drying or vacuum
concentration. The water in the concentrate would be substituted for the
normal daily water intake of 15 gallons per animal. The concentrate would
contain all the protein required by the animals. The pulp drier and the
vacuum evaporator as well as some ancillary equipment are eliminated by this
option which would require trucking of 46 tons of wet pulp and 140 tons of
concentrated juice from the plant to the feedlot daily.
The cost figures for this option are shown in Tables 3 and 4 and yield a
43.9% R.O.I, under the assumption that the feedlot would pay for the feed
values in the pulp but not for that in the concentrated juice.
94
-------
TABLE 2. ANNUAL COSTS, INCOME, AND R.O.I.
ITEM
Rev. Osmosis module replacement
Direct labor (10 months, 3 shifts of 5)
Indirect labor (12 months, 1 shift of 7)
Potatoes (at $0.75/cwt.)
Oil ($13.40 per barrel, 75% effic.)
Electricity ($0.025 per kwhr)
Maintenance (land and buildings at 2%)
Maintenance (equipment at 6%)
Taxes and insurance (3% at fixed costs)
Depreciation on buildings (4%)
Depreciation on equipment (10%)
Interest on working capital
General plant overhead (50% of maintenance
and direct labor)
Total Costs
COST OR INCOME,$
41800
184600
140000
1500000
152600
27700
7300
151900
86900
13100
253100
20000
171900
2750900
Starch ($0.10 per pound)
Pulp ($100. per ton)
Protein ($215. per ton)
Cone, juice ($78. per ton)
3044000
309200
223600
335400
II.
Total Income
3912200
III.
R.O.I.: 40.1%
95
-------
TABLE 3. ESTIMATED FI£ED CAPTIAL INVESTMENT
UNDER LIVESTOCK OPTION
ITEM COST. $
I. Equipment: Same as Table 1 less pulp drier, hammer
mill, conv. sys., and bins; less evaporator; use of
smaller sizes of boiler and fuel tank; but with
larger cone, juice tank. 771700
II. Installation (30Z of I.) 231500
III. Piping, wiring, and control systems (40% of I
and II) 401300
IV. Engineering and contractors' fees (20% of
I, II and III) 280900
V. Contingencies (15% of I, II, and III) 210700
VI. Trucks: Same as Table 1. 117000
VII. Land 40000
VIII. Buildings (somewhat smaller processing area than
used in Table 1). 296800
X. Total Fixed Costs
2349900
96
-------
TABLE 4. ANNUAL COSTS, INCOME, AND R.O.I.
FOR LIVESTOCK OPTION
ITEM
Rev. osmosis module replacement
Direct labor (10 months, 3 shifts of 5)
Indirect labor (12 months, 1 shift of 7)
Potatoes (at $0.75 per cwt.)
Oil ($13.40 per barrel, 75% effic.)
Electricity ($0.025 per kwhr)
Maintenance (land and buildings at 2%)
Maintenance (equipment at 6%)
Taxes and insurance (3% of fixed costs)
Depreciation on buildings (4%)
Depreciation on equipment (10%)
Interest on working capital
General plant overhead (50% of maintenance and
direct labor)
I. Total Costs
COST OR INCOME, $
41800
184600
140000
1500000
65700
25800
6700
120800
70500
11900
201300
20000
156000
2545100
II. Total Income: Same as Table 3 but less income
from cone, juice
3576800
III. R.O.I.: 43.9%
97
-------
SUMMARY
It can be seen from Tables 2 and 4 that income from starch is critical and de-
partures from the assumed $0.10 per pound (18% moisture) will have a great effect
on R.O.I. Thus, a company planning expansion into this area should investigate
carefully how the price of various unmodified starches will vary in coming years
as they can be modified in several ways to meet many of the traditional uses
of potato starch.
The economics discussed in this paper are based on a plant processing 500
tons of potatoes per day (20 hours) of a 200-day season. Various estimates
have placed cull production as 10% of the crop, i.e., somewhat over a million
tons of cull potatoes annually. The plant described would thus process about
one tenth of the nation's cull potato production and would appear to be the
largest practicable. This is especially true in light of recent advances in
potato-based products such as flours and granules which upgrade small potatoes
to food use.
On the other hand, the 76 tons of starch produced by the described plant is
small when compared to corn starch plants in this country or potato starch
plants in Europe. Reducing the plant size would reduce the R.O.I, which is
already borderline (although still acceptable, especially for a farmers'
cooperative) for new plant development.
REFERENCES
1. Rosenau, J. R., Whitney, L. F., and Elizondo, R. Low wastewater potato
starch/protein production process—concept, status, and outlook. Pro.
of the Seventh National Symposium on Food Processing Wastes, Atlanta,
GA (1976).
2. Rosenau, J. R., Whitney, L. F., and Haight, J.R. Potato juice processing.
Proc. of the Eighth National Symposium on Food Processing Wastes, Seattle,
WA (1977).
3. Haight, J. R., Rosenau, J. R., and Whitney, L. F. Process optimization
for dewatering coagulated potato juice protein. ASAE Paper #77-6505
presented to the Winter Meeting of the American Society of Agricultural
Engineers, Chicago, IL, December 13-16, 1977.
4. Rosenau, J. R., Whitney, L. F., and Haight, J. R. Upgrading potato starch
manufacturing wastes. Paper accepted for presentation to the annual
meeting of the Institute of Food Technologists, Dallas, TX, June 4-7, 1978.
5. Anon. Economic indicators. Chemical Engr. 85(2) :7 (1978).
6. Enochian, R. V., Edwards, R. H., Kuzmicky, D. D., and Kohler, G. 0. Leaf
protein concentrate (Pro-Xan) from alfalfa: an updated economic evaluation
ASAE Paper No. 77-6538. Presented to the Winter Meeting of the American
Society of Agricultural Engineers, Chicago, IL, December 13-16, 1977.
98
-------
7. Peters, M. S. and Tiramerhaus, K. D. Plant Design and Economics for
Chemical Engineers, 2nd ed. McGraw-Hill Book Company, New York (1968).
8. Sohns, V. E. Cost analyses for new products and processes development
in USDA laboratories. J. Am. Oil Chemists' Soc. 48(9):362A (1971).
9. Vosloh, C. J., Jr., Edwards, R. H., Enochian, R. V., Kuzmicky, D. D.,
and Kohler, G. 0. Leaf protein concentrate (Pro-Xan) from alfalfa:
an economic evaluation. National Economic Analysis Division, Economic
Research Service. Agricultural Economic Report No. 346 (1976).
99
-------
NITROGEN FIXING BIOMASS FOR AEROBIC
TREATMENT OF SOFT DRINK BOTTLING PLANT WASTEWATER
by
P. Y. Yang* and I. S. Ting**
INTRODUCTION
In order to achieve satisfactory biological treatment of. wastewater, the
wastewater should contain sufficient carbon, nitrogen, phosphorus, and trace
minerals to meet the metabolic requirements for cell growth. For most food
processing wastes, nutritional balance is not a problem since there usually
is enough carbon, nitrogen, phosphorus, and trace minerals. However, certain
food processing wastewaters, such as those from sugar refineries, tapioca
processing, pineapple canning and processing, and soft drink bottling pro-
cessing, have a deficiency of nitrogen which must be added in proper amounts
to achieve appropriate biological treatment of these wastewaters. Modifica-
tion of the activated sludge process for the treatment of nitrogen-deficient
organic wastewaters has been studied (1) (2) in order to achieve effective
COD removal, to reduce the additional cost of nitrogen and to minimize the
nitrogen concentration in the effluent.
Azotobacter sp have long been used as non-symbiotic, free nitrogen fixing
bacteria to improve the yield of a crop (3). This concept has been intro-
duced for the treatment of nitrogen-deficient synthetic wastewater by using
Azotobacter Vinelandii (4). Therefore, the application of this concept for
the treatment of nitrogen-deficient food processing wastewater and develop-
ment of necessary design criteria for the operation of this system will
certainly be useful for the reduction of operational cost and achieve the
necessary effluent quality. The Sermsuk Company, Ltd., Bangkok, Thailand,
has operated an activated sludge treatment plant with an averaged raw waste-
water flow rate of 52 m3/hr (13,738 gal/hr) and COD of 1150 mg/1 for many
years. Handling of this soft drink bottling plant wastewater has created
problems as follows: addition of inorganic nitrogen, bulking sludge, and
excess sludge handling. In order to improve and modify the existing perform-
ance of the treatment plant, studies were carried out for several years at
the Asian Institute of Technology, Bangkok, Thailand (2) (5) (6) (7). How-
ever, it was felt that further study on the reduction of nitrogen addition
and excess sludge production would also be useful if such a process could be
developed.
MATERIALS AND METHODS
Wastewater collected from the soft drink bottling plant of the Sermsuk Com-
pany, Ltd., was used for the present study. In order to enrich the growth
*Department of Agricultural Engineering, University of Hawaii, Honolulu,
Hawaii 96822
**Malaysia International Consultants Co., Kuala Lumber, Malaysia
100
-------
medium, other minerals were added as shown in Table 1. This medium was used
for the development of appropriate nitrogen fixing biomass (NFB) which could
be used for the study of feasibility and kinetic behavior of batch and once-
through continuous cultures. Apparatus for these two cultures are shown in
Figure 1. Volume of aeration chamber for batch and continuous cultures is
1.5 and 6.0 liters,respectively.
TABLE 1. COMPOSITION OF NITROGEN FREE MEDIUM
Composition Concentration, g/liter
0.8
0.2
• 7H20 0.2
• 2H^O 0.1
FeCl2 • 4H20 0.003
NaMo04 • 2H20 0.001
The acclimatized NFB culture (2 milliliters) was transferred to six of 200
milliliters of soft drink bottling wastewater with mineral medium (nitrogen
free) and different initial pH of 5, 6, 7, 8, 9 and 10. These cultures were
then aerated for 9, 16, and 30 hours. Remaining COD and suspended solid
concentrations were measured.
For the comparison of performance of NFB and mixed population (MP) cultures,
batch and continuous flow cultures were operated. In the batch operation,
two kinds of studies were conducted; one for the comparison of NFB (nitrogen
free) and mixed population with supplement of inorganic nitrogen based on
the performances of pH, TKN, suspended solid and COD concentrations, while
the other is the evaluation of biological kinetic constants for the NFB
system. For evaluation of the biological kinetic constants, different ini-
tial COD concentrations of soft drink wastewater were prepared as 50, 100,
200, 400, 600, 800, 1000 and 1300 mg/1. Filtrate COD and suspended solid
concentrations were measured. For the operation of continuous flow (without
sludge recycle) system, different dilution rates of 1/2, 1/3, 1/4, 1/6, 1/8
and 1/13 hour"1 were operated. Steady-state COD and suspended solid concen-
trations were measured.
The analyses of concentration of suspended solids, chemical oxygen demand
(COD), and total nitrogen (Kjeldahl) were followed according to "Standard
Methods" (8).
101
-------
.AERATION CHAMBER
(1.5 liter)
DRAIN
BATCH CULTURE
EFFLUEN
•AERATION CHAMBER
(6.0 liter)
P.K—PUMP
AIR
WASTEWATER
CONTINUOUS CULTURE
FIGURE 1, APPARATUS FOR NFS CULTURE
102
-------
RESULTS AND DISCUSSION
In the present study, the initial NFB was acclimatized with pH 7.0 with ni-
trogen-free soft drink wastewater. Once the NFB was developed, the deter-
mination of optimal range of pH followed. The result is shown in Figure 2.
Apparently, the optimal range is between 6 to 9. This also indicates that
the NFB can be more active with high pH than with low pH.
The general performance of NFB and MP systems in the batch operation is shown
in Figure 3. It indicates that both systems perform at the same efficiency
of COD removal but differ in the accumulation of suspended solid concentra-
tions and TKN contents. In the NFB system, less accumulation of suspended
solid concentration and lower TKN content results as compared to the MP sys-
tem with the same initial COD concentration. Apparently, the biological
kinetic behavior of the NFB system has merit. As shown in Figures 4, 5 and
Table 2, the yield value (Y), maximum growth rate (vim) and saturation con-
stant (Ks) are different in both systems. Lower value of cell yield in the
NFB system would certainly represent an important parameter for excess
sludge handling as practiced in the conventional activated sludge process.
In addition, the lower value of TKN in the effluent of the NFB system is
very important since higher content of nitrogen concentration in the effluent
will cause an eutrophication problem in the receiving stream.
TABLE 2. COMPARISON OF BIOLOGICAL KINETIC CONSTANT
Biological
Kinetic Constants NFB System MP System (9)
ym, hour"1 0.30 0.62
Kg, mg/liter 260 125
Y, mg/mg 0.137 0.53
In order to observe the operational characteristic of continuous flow opera-
tion, these two systems were operated as once-through continuous completely-
mixed flow with different dilution rates. The results are shown in Figures
6 and 7. According to the dilute-out curve shown in Figure 6, the NFB sys-
tem shows no wash-out of suspended solid even when 0.5 hour"1 of dilution
rate is provided. This does mean that the volume of the secondary settling
chamber can be drastically reduced for handling of the secondary sludge pro-
duced from the aeration chamber. Furthermore, the effect of dilution rate
on the cell yield values and COD removal efficiency for these two systems
are shown in Figure 7. It can be seen that the NFB system provides nearly
the same COD removal efficiency with the MP system with much lower cell
yield values at different dilution rates as compared to the MP system. Ap-
parently the NFB system utilizes a greater portion of the substrate as an
energy source for the nitrogen fixation process rather than synthesis of
103
-------
V)
Q
Lu
CL-
IO
CO
300
200
100
56789
INITIAL pH VALUES
INCUBATION TIME
o 30 hrs
a |6 hrs
? 9 hrs
FIGURE 2, OPTIMAL pH DETERMINATION
104
-------
X
a.
9.0
8.0
7.0
Q
O
tt
CO
Z3
CO
\ 400
300
200
100
0
75
50
25
0
\
\
o»
Seeded with NFB
Seeded with Mixed population and
•upplemenlated (NH,XS04 at ratio of
N/COD* 1/20
6 12 IS 24 ^ 50
INCUBATION TIME, hrs.
FIGURE 3,COMPARISON OF NFB AND MP CULTURES
105
-------
s
cO
2 150
Q
uJ
Q
fOO
50
ID
C/D
Y--0.1375
0 200 400 50O 800 1000 I2OO
COO UTIUZED mc^,
FIGURE 4 j YIELD COEFF(CENT CURVE IN BATCH CULTURE
o
o
UJ
UJ
Or
cr
H
cO
03
Z>
CO
O
o:
o
d
o
LU
CL
CO
200 40O 6OO 800 lOOO 1200 I4OO
^INITIAL SUBSTRATE CONCENTRATION;mg/(
FIGURE 5, DETERMINATION OF MAX. SPECFIC GROWTH RATE ty*
AND SATURATION CONSTANT K IN BATCH CULTURE
106
-------
cr«
c/)
c/5
1000
800
600
400
200
EFF. COD (NFS)
EFF.GOD (MP)
MLSS (MP)
MLSS (NFB)
0 0.1 0.2 03 04
DILUTION RATE hr~*
FIGURE 6; DILUTION CURVE FOR NFB AND MP SYSTEMS.
"„ K)0
>-
o
| 80
O
u_
u_
^ 60
40
LU
OL
o 20
o
o
0
01
0.2 03 04 05
100
80
60
40
20
0
g
LJ
LU
O
DILUTION RATE hr
~'
FIGURE ^ EFFECT OF DILUTION RATE ON COD REMOVAL AND
YIELD VALUE
107
-------
biomass as the MP system does. According to the present study, it is shown
that the NFB system can be operated as the MP system except for nitrogen
addition.
The present study provides a potential which can be explored for further
study on the operation of sludge recycle continuous flow systems which can
be more practical in actual operation.
SUMMARY
It is technically and economically feasible to treat the nitrogen-deficient
carbohydrate wastewater by the NFB system with effective COD removal, low
sludge production and low nitrogen content in the effluent. Biological
design constants including maximum specific growth rate of biomass, satura-
tion constant and cell yield value are different for the NFB and MP systems.
Further study should be conducted with the NFB system on the biological
kinetic behavior of sludge recycle continuous flow completely-mixed system.
ACKNOWLEDGEMENT
This work was supported by scholarships donated by the Lee Foundation, Singa-
pore, through the Asian Institute of Technology, Bangkok, Thailand. Also,
this paper was approved by the Director of the Hawaii Agricultural Experiment
Station.
REFERENCES
1. Komolrit, K., Goel, K. C., and Gaudy, A. F. Jr., Regulation of exogenous
nitrogen supply and its possible application to the activated sludge
process. J. Water Pollution Control Federation 39:251 (1967).
2. Yang, P. Y., and Chan, L. K. Modified activated sludge process for treat-
ment of nitrogen-deficient organic wastes. J. Water Pollution Control
Federation 48:1992 (1976).
3. Goldschmidt, M. C., and Wyss, 0. Chelation effects on Azotobacter cells
and cysts. J. of Bacteriology 91:120 (1966).
4. Finn, R. K., and Tannahill, A. L. The azotopure process for treating
nitrogen-deficient aqueous wastes. Presented at 164th National Meeting
of American Chemical Society, N. Y., August, 1972.
5. Tsui, T. S. Soft drink bottling plant wastes handling study. M. S.
Thesis No. 640, Asian Institute of Technology, Bangkok, Thailand (1975).
6. Yang, P. Y., and Chen, Y. K. Operational characteristics and biological
kinetic constants of extended aeration process. J. Water Pollution
Control Federation 49:678 (1977).
108
-------
7. Yang, P. Y. Biological kinetic behaviours and operational performances
in the aerated and oxygenated systems. Biotechnology and Bioengineering
19:1171 (1977).
8. Standard Method for the Examination of Water and Wastewater. 13th Ed.,
American Pub. Health Assn., New York (1971).
9. Yang, P. Y., Hsu, C. H., and Thijayung, C. Biological kinetic behaviour
of completely mixed air and pure oxygen systems. Proceeding. IFAC on
Environmental Systems Planning, Design and Control, Pergamon Press.
p. 723 (1977).
109
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TREATING TROUT PROCESSING WASTEWATER -
A SUCCESSFUL CASE HISTORY
John S. Keith, P.E.*
INTRODUCTION
The Thousand Springs Trout Farms, a subsidiary Pf
Corporation, is a producer of fresh and frozen rainbow trout
for the restaurant market. It is located in the beautiful Snake
River Canyon, outside Buhl, Idaho. In this paper, the wastewater
problems of Thousand Springs trout processing plant will be
discussed, and the efforts made to clean up the wastewater will
be reviewed.
Historically, the wastewater from Thousand Springs' processing
plant was never considered a pollution problem. First of all,
the amount of wastewater involved - around 70 gallons per minute -
was insignificant when compared to the water discharged by the
adjacent trout farm — some 45iOOO gallons per minute. And second,
the contaminants in the wastewater were considered as generally
good for the receiving waters - an opinion supported by the
large population and record size of trout in Clear Lake, the
receiving water for Thousand Springs. Consequently, the only
wastewater treatment done was coarse screening. However, in
order to comply with the strict limits of Thousand Springs'
NPDES permit, it was clear that a major clean-up program would
be necessary. A two stage program was planned i first, reducing
the amount of pollution coming from the plant by improving water
use practices; and second, installing an effective end-of-pipe
treatment system.
IN-PLANT CLEAN-UP
The first step of any water pollution control project is to
define the problem. This was done by carefully inspecting the
processing plant, identifying specific wastewater source opera-
tions, and conducting a sampling program. To insure the validity
of data obtained, great care was taken when conducting the
initial wastewater sampling, and all subsequent sampling! com-
posite samples, encompassing all production activities, were
taken for several days. Where possible, the results were
correlated with historical data.
Upon evaluation, it was found that four operations were respons-
ible for virtually all of the processing plant wastewater.
*Inmont Corporation, Corporate , Engineering Department
Hawthorne, New Jersey
110
-------
These operations werei evisceration of the trout by automatic
"gutting machines"; manual rinsing and cleaning of eviscerated
trout at "rinse tanks"', manual boning of the cleaned fish at long
"boning tables"', and washing down of the processing equipment and
work areas at breaks and the end of shifts. Wastewater from this
last operation was commonly called "floorwater", after the worker's
custom of allowing wash water hoses to run continuously on the
plant floor. Other operations at the plant —chilling, inspection,
weighing, packing and freezing — were found to involve little or
no wastewater.
The results from the initial sampling program are given in
Table I. In general, the plant effluent was found to be quite
foul. It had a color varying from light to dark pink, a high
degree of turbidity, a definite fishy odor, and a somewhat greasy
feel.
As can be seen from the table, the gutting machines were by far
the most significant source of pollution in the plant, contri-
buting about 36jf of the total flow and over 90jf of the contami-
nation. This result was not surprising; it is at the eviscer-
ating machines that the fish are first opened up, and the
"pollutants" - blood, body fluids, and solids - first allowed
to mix with water. Compared to the gutting operation, rinsing
and boning were not significant sources of contamination, although
the boning tables did contribute an unexpectedly high portion of
the total wastewater flow. No practical way was found to sample
floorwater. However, based on appearance, the floorwater did
not appear to get worse than the average plant effluent, and
was usually much cleaner.
The next step in the clean-up program was to determine how the
water use practices at each source could be improved. Since it
was already clear due to the strictness of the NPDES permit that
end-of-pipe treatment would be necessary, methods for reducing
both the degree of contamination and the quantity of wastewater
were investigated, so that the treatment system would be as small
as possible.
By inspection, it was clear that the "floorwater" could be easily
reduced. There was no apparent reason why wash hoses had to be
left on at all times, so plant personnel were instructed to turn
off the hoses when not in use.
After considerable review with the plant supervisors, it was
decided that water use at the boning tables could be eliminated
almost entirely. Basically, the boning water was used only as
a means for conveying bones away from the worker's stations.
To eliminate this water conveying system, plastic buckets were
placed next to each worker's station. The bones are now directed
into buckets by chutes, and are carried away by a designated
employee. While more labor is involved, a very considerable
111
-------
TABLE I - INITIAL WASTEWATER CONDITIONS
Parameter
Flow (gpm)
BOD5 (mg/1)
TSS (mg/1)
Oil tt Grease (mg/1)
Plant
Effluent
67-3
502
295
690
Gutting
Machines
24.4
1820
3186
1722
Rinsing
Tanks
11.9
190
94
168
Boning
Tables
23.8
115
22
4
Notes Floorwater could not be isolated for sampling
TABLE II - RESULTS OF CLEAN-UP PROGRAM
Reduc- Reduc-
Effluent Effluent tions tions
Effluent After After After After
Modifi- Treat-
Parameter
Before
Clean-up cations ment
Modifi- Treat-
cations ment
Avg. Flow (gpm)
Max. Flow (gpm)
BOD*
(lb/1000 Ib Fish)
TSS
(lb/1000 Ib Fish)
Oil & Grease
(lb/1000 Ib Fish)
67-3
75
19.8
11.6
27.2
29-3
30
14.0
6.6
2.3
25.3
30
2.3
1.2
0.4
62. 4*
60*
29-3*
43-1*
91-5*
60*
89.7*
112
-------
reduction of wastewater was achieved, and surprisingly, the
Zoning area is a bit cleaner (the water conveying system was
prone to frequent plugging).
At the rinse tanks, the trout are checked to see if the
gutting machines have cleaned out all the viscera. The fish
are rinsed and any remaining viscera is manually removed. Only
a slight reduction in water use was achieved at this source.
However, a fair amount of contamination was prevented by having
the removed viscera placed into a trough leading to a bucket,
rather than thrown into the rinse tanks.
Because the gutting machines were the major water pollution
source in the processing plant, more effort was spent on
cleaning up them than the other sources. By reducing water
flow rates at the various sprays and nozzles in the machines,
water consumption was cut about in half. However, this did
not significantly affect the amount of contamination. To
reduce contamination, a scheme for removing viscera from the
wastewater right at the machines was tried. This idea was
based on information in the literature indicating that the
longer fish viscera is allowed to remain immersed in water, the
more contaminants leach out into the water (1). To test the
idea, a makeshift separation system was installed. Test samples
showed very promising results — a 33^ reduction in BOD and a
59# reduction in oil and grease. With the importance of the
leaching phenomenon confirmed, attempts were made to install a
permanent separation system right at the gutting machines.
While such a system was eventually completed, it proved to be
rather cumbersome, labor intensive, and prone to breakdowns.
Fortunately, while the viscera separation system was being
worked on, the management at Thousand Springs was also investi-
gating more modern gutting machines — machines that employed a
vacuum for removal of viscera, rather than mechanical removal
and water disposal. The new machines were being considered
primarily for production reasons, but the managers were
confident that they would help with the wastewater problem.
The machines were purchased and installed in the summer of
1977, and have proved to be significantly less polluting than
the old machines. This is because with vacuum removal, the
viscera and much of the blood is sucked away and does not mix
with any water. Water consumption by the new machines is also
less than by the old machines.
Some mention should be made about the method of disposing of
the fish viscera, bones, etc. from the processing plant. The
wastes are picked up daily and hauled away as animal feed for
mink — who apparently love it. When significant changes in the
waste handling methods were made, the effects of these changes
on the mink farmers was considered. Generally, the owners of
the mink farms were accommodating to Thousand Springs' needs.
113
-------
In some ways they even came out ahead as a result of the changes.
After all the water use changes and modifications in the pro-
cessing plant were completed, samples of the plant effluent were
again taken. Table II gives the results of these tests, along
with the initial test results, and the results of tests done
after installation of the treatment system. As Table II shows,
the in-plant changes resulted in considerable reductions in
wastewater flow rates and in overall contamination. In view of
these reductions, the -first stage of the clean-up program was
judged to be successful.
It should be noted that the results concerning BOD, TSS, and
oil and grease are given in terms of pounds of contaminant per
thousand pounds of fish processed. Since production at the
processing plant has more than doubled since the wastewater
clean-up program began — to a current production peak of over
30,000 lbs/day>-such a production-based measure is necessary
to allow meaningful comparisons.
TREATMENT SYSTEM INSTALLATION
After the various changes in the processing plant were in place
(except for the new gutting machines, which weren't installed
until later) , an investigation was made into what type of treat-
ment system to install. Performance criteria for a treatment
system were based on what was needed to achieve compliance with
the final limits of Thousand Springs' NPDES permit.
When evaluating wastewater treatment strategies, the problem of
space was very important. The Thousand Springs Trout Farm is
very short on space, and any large treatment system would have
cut into productive fish impoundments. The only readily avail-
able space was a little-used building at the outfall end of the
trout farm, measuring about 16 feet wide, 30 feet long, and 9 to
feet high.
Several treatment strategies were investigated, including lagooning,
extended aeration, activated sludge treatment, chemical treatment
and air flotation. Lagoons and extended aeration systems were
ruled out because of space requirements. Chemical treatment
was eliminated because of generally low treat ement efficiencies
and lack of data relating to fish processing wastewater.
Activated sludge systems were found to be feasible » however,
such systems still required somewhat more space than was readily
available. Also, they would cost more than twice as much as air
flotation systems, and would have trouble with the high oil and
grease loadings.
The literature indicated that air flotation systems, with chemi-
cal additions, could treat fish processing wastewater as effec*
114
-------
tively as conventional "biological treatment systems, and yet
take up very little space (1) (2). A number of flotation
system manufacturers were contacted and invited to submit pro-
posals based on the performance criteria. Both dissolved-air
and dispersed-air flotation systems were considered. The
system selected was a dispersed-air flotation system with
chemical addition and fine screening, proposed by SWECO, Inc.^.
SWECO was selected primarily because they appeared to have tKe
most experience with fish processing wastes and because they
could guarantee the greatest BOD removals.
Wastewater treatment in the SWECO system is done primarily by
three pieces of equipment — a coarse belt screen, a centrifugal
screen concentrator (CSC), and a sludge flotation tank. The
belt screen consists of a series of polyethylene panels with
l/^K-inch openings. The CSC is essentially a rapidly rotating
drum with screens on the outside, through which the wastewater
is pumped from the inside. It uses 165-mesh stainless steel
screens. The flotation tank measures & feet wide, 12 feet long,
and ^ feet deep, and is equipped with a foam skimmer.
Other components of the SWECO system are a 300-gallon surge tank,
a non-clog wastewater pump, a vibrating separator with 165-mesh
screens, three chemical feed tanks and pumps, an automatic
screen washing system, a 1500-gallon sludge holding tank, and
an integrated control panel. The system operation is described
below.
Wastewater from the processing plant flows by gravity to the
SWECO room. Once there, it falls through the coarse belt
screen into the surge tank. Large pieces of fish viscera are
removed by the belt screen, and are dumped into a chute leading
to the sludge holding tank. The surge tank serves to level out
peaks in the wastewater flow rate. Alum is added to the waste-
water at the surge tank.
From the surge tank, the wastewater is pumped to the centri-
fugal screen concentrator, with lime being injected into the
stream right after the pump. The CSC serves two functions!
it removes fine solids, and it aerates the wastewater. Solids
removed by the CSC flow out the bottom of the unit to the vibra-
ting separation screen, which dewaters them. The dewatered
solids are discharged to a drum, while the water is recirculated
back to the surge tank. Just prior to leaving the CSC unit, an
anionic polymer is injected into the wastewater stream.
The wastewater then flows by gravity to the bottom of the
flotation tank. There, the fine floe formed due to the alum
and lime addition is coalesced by the polymer and floated to
the top of the flotation tank by entrained air. A moving
skimmer pushes the floating, foamy sludge over a collection weir
115
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into a trough, from which it flows to the sludge holding tank.
After skimming, the fully treated wastewater is discharged
over another weir. Sludge and solids collected in the holding
tank are periodically pumped out and hauled away to a landfill.
The entire treatment system is controlled from one control panel,
and can be operated either manually or automatically. Periodically,
the system cycles into a cleaning mode. In this mode, the fine
screens of the CSC unit and vibrating separator are backwashed
by a high pressure spray of hot water mixed with detergent.
With regard to space, the SWECO treatment system fits quite
comfortably into the l6-by~30 foot room available, with ample
room left over for a workbench and storage shelves. The sludge
holding tank is located underground outside the room.
As with most complex installations, the start-up of the SWECO
treatment system had a few problems. In particular, problems
were encountered with the wastewater pump due to stringy solids,
and with the coarse screening operation (not part of SWECO's
package). But for the most part, these problems have now been
overcome. Initial chemical concentrations were as suggested by
Barnett and Nelson in their studies - 220 mg/1 of alum, 150 mg/1
of lime and 5 mg/1 of polymer (2).
The results of tests to determine the efficiency of the SWECO
system are shown in Table III belowi
TABLE III - PERFORMANCE OP SWECO SYSTEM
Raw Treated Treatment
Parameter
BOD5 (mg/1)
TSS (mg/1)
Oil and Grease
Wastewater
1180
562
(mg/1) 189
Wastewater
189
100
28
Efficiency
8W
82*
85*
The tests show that the system is quite efficient in treating the
wastewater. It should be noted that when the tests were made, no
effort had yet been made to optimize removals by adjusting chemi-
cal feed rates, cleaning frequency, etc. After some experience,
removal efficiencies are expected to be even better.
CONCLUSIONS
Referring again to Table II, it can be seen that, overall, the
wastewater clean-up program at the Thousand Springs Trout Farm
116
-------
was very successful. Reductions of BOD and suspended solids
were close to 90#, and the reduction of oil and crease was a
remarkable 98.5#- As experience is gained with the SWECO
treatment system, better reductions may be achieved.
Considering the reductions obtained, it is felt that the cost
of the clean-up program was very reasonable. Installed cost
of the SWECO treatment system was about $60,000 (197? dollars),
while the cost of the entire clean-up program was about $80,000.
These cost figures include all testing and engineering, but
do not include the cost of the new gutting machines, which were
installed primarily for production reasons. The cost figures
also do not include the labor of Thousand Springs Trout Farm
personnel, who contributed nearly all of the labor involved in
the project.
REFERENCES
1. Environmental Associates, Inc. Upgrading Seafood
Processing Facilities to Reduce Pollution. Environ-
mental Protection Agency Technology Transfer
Program (197*0 •
2. Barnett, Harold J., and Nelson, Richard W. A Preliminary
Report on Studies to Develop Alternative Methods of
Removing Pollutants from Tuna (Albacore) Process
Wastewaters. Unpublished.
ACKNOWLEDGMENT
The author would like to express his sincere appreciation to
Messrs. S. Davis, M. Fennen, and R. Eggleston of the Thousand
Springs Trout Farm for their untiring work towards the success
of this project.
117
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RECIRCULATIOlN OF CONTAINER COOLING WATER
ASA MEANS OF WATER CONSERVATION
IN FOOD PROCESSING PLANTS
by
Nabeel L. Jacob*
INTRODUCTION
Water is the most common medium used for cooling thermally processed
containers of food. Cooling is accomplished in a variety of systems such as
the use of still retorts as coolers, cooling canals, agitating spin coolers,
rotary pressure or atmospheric coolers, spray coolers or water application
in the cooling leg of a hydrostat ( 3 ). In general, cooling water is either used
once and discharged or reused for cooling, or other purposes.
Container cooling is one of the most water consumptive operations in any food
processing plant. Depending on the type of product packed and the water use
practices, cooling water requirements represent between 25 to 85 percent of
the total volume of water used daily in the plant ( 1 , 3 ). Acquisition of such
a large volume of water is no longer free even for the processors who rely
exclusively on wells for their fresh water supply. Disposal of wastewater,
whether to a municipal treatment plant or to a company operated treatment
facility, has also become a significant cost item in food processing. There-
fore, maximizing the use of such a copious volume of good quality cooling
water, through recirculation or reuse, can be an effective means of im-
plementing a successful, overall water conservation program through which
substantial savings can be realized ( 3 ).
NFPA SURVEY OF CONTAINER COOLING SYSTEMS
Recognizing the significance of the microbiological, chemical and physical
characteristics of cooling water as major factors determining the feasibility
and extent of its reuse, a survey was conducted by NFPA (formerly NCA) to
specifically determine these characteristics in a number of container cooling
systems.
Over the two-year period of the project, a total of sixty-five (65) visits were
made to seventeen (17) California canneries where 210 cooling water samples
*National Food Processors Association, Western Research Laboratory,
Berkeley, California.
118
-------
were collected for laboratory testing. The study covered seven (7) different
cooling systems, eight (8) major commodities and twelve (12) specialty prod-
ucts.
In general, samples were collected in various ways depending upon the type
of cooling system surveyed. At the time of sampling, the concentration of
total residual halogen (chlorine or iodine) in the water was determined and
the temperature and pH were recorded. Residual chlorine or iodine in water
samples collected for microbiological testing was immediately neutralized by
adding sterile 1% sodium thiosulfate solution. Samples were then refrigera-
ted, for no longer than 40 hours, until examined. All laboratory tests were
performed in accordance with the Standard Methods for the Examination of
Water and Wastewater ( 5 ).
RESULTS AND DISCUSSION
The physical and chemical characteristics of the samples collected are sum-
marized in Table I. The total hardness (as CaCO3) showed the highest de-
gree of dispersion as determined by the standard deviation value. The least
variability was that of the pH of the water. The TOG/COD ratio had a range
of 0. 10-4.41 with an arithmetic mean of 0. 63 and SD of 0. 69. Halogen con-
centration will be considered in a later part of the discussion.
TABLE I. SUMMARY OF CHEMICAL AND PHYSICAL CHARACTERISTICS
Characteristic
COD, ppm
TOC, ppm
TSS, ppm
Hardness (CaCO3), ppm
Grease & Oil, ppm
Temperature, °C
pH
Range
0. 0
0.0
0.0
10.0
0. 0
9.4
6.0
- 281.0
- 77.0
- 98.0
- 500. 0
- 23.0
- 66.7
- 9.6
Mean
26.9
12. 8
4.4
92.7
4.0
28. 1
8. 1
S.D.
37.8
11.5
6.3
87.8
4.2
19.5
0.53
Microbiologically, the aerobic Total Plate Count (TPC), aerobic and anaer-
obic Mesophilic Spore (MSC), Staphylococci and Coliform Counts were deter-
mined in the cooling water samples. Table II gives a summary of these
characteristics.
119
-------
TABLE II. SUMMARY OF MICROBIOLOGICAL CHARACTERISTICS
Characteristic Count/ml (Range)
Total Plate Count (TPC) <1 - 205,000*
Mesophilic Spore Count (MSC)
a. Aerobic < 1 - 20
b. Anaerobic < 1 - 4
Staphylococci <1 - 13
Coliforms <1 - 950*
*No detectable germicide residue.
An examination of the percentage distribution of bacterial counts in the
samples (Table III) indicates that 64% of the water samples had TPC in the
range of < 1 - 100/ml. Of these samples, 40% showed negative results
(< I/ml). The MSC was generally low. There were no detectable aerobic
sporeformers in about 80% of the samples, and the maximum count did not
exceed 20/ml. Anaerobic sporeformers were only recovered from 4% of the
samples and at low density levels (highest count was 4/ml). Staphylococci
counts of between 1 and 10/ml were present in only 3% of the samples.
Densities of more than 10/ml (with a maximum of 13/ml) were encountered
in 1% of the water samples. Toxin tests were negative in all samples that
showed positive Staph results. Coliforms were detected in about 12% of the
samples.
TABLE III. PERCENTAGE DISTRIBUTION OF BACTERIAL COUNTS
IN COOLING WATER
MSC
Counfc/rnl
<1
1 - 10
11 - 100
101 - 1,000
1,001 - 10,000
10,001 - 100, 000
> 100, 000
TPC
25.6
19.5
19.0
16.4
9.7
6.7
3. 1
Aerob.
79.5
17.9
2.6
-
-
-
_
Anaerob. Staph.
96.4 96.4
3.6 2.7
0.9
-
-
-
_ _
Coliforms
88.2
0.9
1.8
9.1
-
-
120
-------
Occurrences of aerobic sporeformers in relation to different ranges of TPC
had no definite trend. The anaerobes, on the other hand, showed a steady
increase with the TPC in ranges higher than 100/ml.
The frequency of coliform and staphylococci detection increased as the
general bacterial population increased to maximum levels. However, no
linear trend was apparent.
MAXIMIZING THE USE OF CONTAINER COOLING WATER
Because of the recent drought conditions that affected the western and mid-
western states, food processors should make every effort to maximize the
use of container cooling water. This can be basically accomplished through
reuse. The results obtained and observations made in our study indicate
that the voluminous discharge (Table IV) from container coolers is, in most
cases, more than suitable for reuse, with minimal treatment, in lieu of
fresh water.
TABLE IV. VOLUME OF WATER DISCHARGED FROM VARIOUS
TYPES OF COOLERS
Type Range
Still Retorts 1300 - 4000 Gal./Cooling Cycle
Spray Coolers 6300 - 20,000 Gal./Hr.
Spin Coolers 3700 - 6300 Gal./Hr.
Cont. Coolers 2400 - 6000 Gal./Hr.
The reuse of cooling water can be implemented in two ways with the option of
employing both, or either one exclusively (Fig. I):
REUSE OF COOLING WATER
For Container Cooling For Purposes Other
"Recirculation" than Cooling
• Fluming
- Product Washing
Over a Cooling Within the
Tower Cooler • Plant Clean-Up
• Incidental
• All Types • Spin Coolers
• Spray Coolers
Fig. I. Water conservation through reuse of cooling water.
121
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1. The reuse for purposes other than container cooling;
The discharge from cooling systems can be reused without further
treatment for fluming and product washing ( 1, 3, 4) thus eliminat-
ing a number of points of fresh wateruse. This practice is known
as the counter-flow reuse pattern which can be adapted in various
ways in most food processing plants. Water conservation acquired
through this practice is depicted in Fig. II which illustrates three unit
operations common in all food processing plants.
SINGLE USE
50 Gpm •> [ FLUME ] — *• 50 Gpm
50 Gpm + WASHER | — * 50 Gpm
CAN
50 Gpm *• — *• 50 Gpm
V COOLER H
I 150 Gpm
REUSE
[-»- FLUV
1
10 Gpm — ^+\ WAS
CAN
50 Gpm *•
v COO
IE ) — *• 60 Gpm
HER *,
J
IR
I 60 Gpm
Fig. II. Counter-Flow reuse of cooling water.
Discharge from coolers can be used also for plant clean-up, belt lub-
rication and boilers { 1 ).
2. The reuse for container cooling purposes;
This method can be implemented through either, or both, of two ways;
(a) Recirculation of the water within the cooler. This can be readily
accomplished in spray and spin coolers. In spray coolers (Fig.
Ill), fresh water consumption is significantly reduced by collect-
ing the water under the final section of the cooler and reuse it in
the preceding section and so on. Water collected under the initial
section can then be discharged, reused for other purposes or re-
circulated over a cooling tower and reused for cooling. The same
concept applies to spin coolers as illustrated in Fig IV.
122
-------
HOT
WATER
o
PRODUCT
IN
t-o
CO
/Vl9oPF./\ /\
STERILIZING COOLING
— •* n. n
i.~_~ HOT- rrr~jr JT 'HOT'-"^-
Lirdj"
— |
1
•' \ •' x\
COOLING
COLD
WATER
o
COOLING COOLING
COMBINED EFF.
TROUGH
Fig. III. Water recirculation within the cooler "spray cooler. "
-------
PRODUCT
IN
"^^\
^*^s
-- - -_ - --*! -L- ~~ - - --
J^^~\:
-N:1^
-V-
t
x^^-
^/r~_~_~ —
- — — — — — — _ __
K
.*
\
1
':]
V.
\\
PUMP
TO SUMP
Fig. IV. Water recirculation within the cooler-"spin cooler. "
-------
(b) Recirculation of the discharge from coolers over a cooling tower
and reuse for container cooling. This practice, as illustrated in
Fig. V, may require some revision of the existing hydraulic flow
in the plant. However, reductions of as high as 80% of the daily
cooling water consumption have been reported by plants now
using cooling tower systems.
CANS IN
r
I COOKE
^
1
TO SA
TOWEF
R
— Q-
COOLER n|
D
T
....... TANK fll IT
-S'SSJ ^HIMj UUI
:SUMPJ
L
NITIZE
\
& CHLO
i
RINE
I
r
L.LJ.J
: COOLING.;:
E TOWER =
2 i.~L~L~_r.
PSUMP^
/s's' / S^S
WATER
MAKE-UP
-< J
>•
RETURN TO TOWER
Fig. V. Schematic of a cooling tower system.
It should be emphasized at this point that water used in recirculated systems
is particularly prone to bacterial and organic matter build-up as shown by
the survey data. Table V shows the effect of recirculation on various charac-
teristics of cooling water. The build-up trend is apparent. Therefore, the
operation of recirculated cooling water systems requires special attention to
avoid adverse conditions.
125
-------
TABLE V. THE EFFECT OF RECIRCULATION ON THE
CHARACTERISTICS OF COOLING WATER
Characteristic
COD, ppm
TOC, ppm
pH
Residual, C12, ppm
Bacterial Counts/ml:
TPC
MSC (Aerobic)
" (Anaerobic)
Staph.
Coliforms
Single - Pass
(28% of Samples)
0.0 - 133.0
0.6 - 48.5
7.6 - 9.6
0.0 - 9.5
<1 - 1680
<1 - 2
<1
<1 - 1
10.0
<1 - 205,000*
<1 - 20
<1 - 4
<1 - 13
<1 - 950*
*Cooling water contained no detectable germicide residue.
MEANS TO ACHIEVE MAXIMUM USAGE OF COOLING WATER
Based upon the findings and upon the observations made throughout the study,
the following considerations are offered collectively as necessary means of
maximizing the use of cooling -water:
1. Adequate Knowledge of the System;
This is the first requirement in any water conservation program. Seri-
ous problems may result from the lack of knowledge of what I call "the
system plumbing. " Misapplication of chlorine, in recirculated water
systems, is an example. Therefore, you should survey the system
and maintain an updated floor plan or a schematic diagram with all
water lines, points of chlorine application, sumps -- etc., indicated
thereon. An example of such a map is shown in Figure VI. This map
is specifically useful in trouble-shooting.
2. Disinfection:
Disinfection is probably the most effective means for achieving maxi-
mum usage of cooling water. Our study has shown that the presence
and level of a germicide residual in the cooling water determine to
126
-------
-6- GftTE
FIOAT VALVE
NJ
IW- PLANT
USfS
SUMP
COOLIN&
TOWER
—I —&-a-
9x
QQQ
X
I •
C-lt 1
Y HOLD T/SMK
*-4
N '
-n_n 1
CHLOR.\^4ATBD
JP H^O
-f-1
Fig. VI.
-------
a large extent the microbiological quality of the water which in turn
determines the feasibility of its reuse. Table VI shows the definite
effect of the concentration of residual chlorine on the microbiological
quality of cooling water. As expected, the results indicate a general
trend towards lower counts of all four groups of microorganisms with
increasing residual chlorine level. In general, all bacterial counts
were highest when the level was undetectable or low (0. 0-1.0 ppm).
No bacterial growth was encountered, however, at concentrations
higher than 3, 1 ppm.
Selection of the proper germicide should be based upon careful con-
sideration of the following aspects:
(a) Thorough evaluation of the germicidal efficacy acquired under
typical operational conditions.
(b) The corrosivity of the germicide and the effect of its use on the
characteristics of the water.
(c) The regulatory status of the germicide.
(d) The compatabtlity of the germicide with other chemicals added to
the cooling water (e.g., oxygen scavengers).
(e) The cost and added benefits.
For several well known reasons, gaseous chlorine is still the prefer-
red choice of most food processors. However, chlorination of con-
tainer cooling water definitely requires adequate control of the resi-
dual chlorine levels in the water. Inadequate control results in either
corrosion of containers and equipment or high bacterial counts and
the absence of sanitary conditions in the water.
It is evident that the stability and germicidal efficiency of a given con-
centration of chlorine are greatly influenced by the pH, temperature,
total suspended solids (TSS) and organic load of the water. Therefore,
the characteristics of cooling water will determine, to a large extent,
the required minimum level of chlorine. By considering the hardness
of the water, corrosivity can also be predicted ( 3 )•
To achieve adequate control of the established level of residual chlorine,
the plant must have an individual assigned to monitor and maintain re-
cords of residual chlorine concentrations in the cooling water on a
continuous basis. Monitoring program should include both water feed-
ing, and water discharged from, the cooler. Monitoring of residual
chlorine in the latter assures the adequacy of chlorine dosage applied
to the first.
128
-------
TABLE VI. THE EFFECT OF RESIDUAL CHLORINE CONCENTRATION
ON BACTERIAL COUNTS* IN CONTAINER COOLING WATER
to
VO
Resid. C12
Rangej ppm
0. 0 - 1. 0
1.
2.
3.
4.
1-2.0
1-3.0
1-4.0
1 - 10. 0
>10. 0
%
MSC
of Samples TPC Aerobic Anaerobic Staph. Coliforms
52.9
14.4
12.3
5.4
13.4
1.6
<1 - 205,000
-------
Monitoring and control can be done either manually or automatically.
Orthotolidine comparators, or alternate methods such as the use of
"Water-Chex" for chlorine, are normally used at the cannery to
determine chlorine concentration in the water. Chlorine dosage is
then manually adjusted on the basis of that reading.
Automatic monitoring and control systems, currently available, con-
sist of four major components; an analyzer, a recorder, a controller
and an automatic valve on the chlorinator to adjust chlorine dosage.
These automatic chlorine monitor/controllers are particularly useful
in recirculated cooling water systems.
lodophors (surfactant-iodine complex) have been in use for several
years as sanitizing agents. However, the practical experience with
these compounds for the specific application of disinfecting container
cooling water is extremely limited. Our study of the very few cooling
systems using iodophors has revealed some shortcomings. An example
is the adverse effect on the characteristics of the water exerted by the
phosphoric acid, and organic surfactant contents of the iodophor. The
first caused the pH range to drop to 2. 9 - 4. 8 in the cooling water, and
the latter increased the COD range from 0. 0 - 281. 0 ppm to 470. 0 -
969.0 ppm. Therefore, an in-depth stu4y of the effectiveness of these
compounds, under typical production conditions, is necessary betore an^ con-
clusions can be drawn.
Chlorine Dioxide should not be considered as a direct replacement for
chlorine in all cases (7 ). The advantage of C1O2 is that it offers better
germicidal efficiency in situations where chlorine is adversely affected
by conditions that exist in the water to be treated. Persistently high
content of organic matter, especially phenolic and nitrogenous com-
pounds, and excessively high pH are mainly the adverse conditions that
affect chlorine. These conditions are not normally encountered in con-
tainer cooling systems. Application of C1O2 also involves some cost
and safety consideration.
3. Regulations;
For the low-acid food processors, the GMP regulations (CFR 21:
113. 60) advises that cooling water be chlorinated as necessary so
that there is a measurable free chlorine residual, or its equivalent
of other safe chemicals, in the water at the discharge end of the
cooler. This regulation is currently under revision by FDA and is
expected to be mandatory.
In single-pass systems, a concentration of at least 0.5 ppm of resi-
dual chlorine, measured at the discharge point, is adequate (2,6).
130
-------
Recirculation of cooling water normally requires higher concentra-
tions due to the potential build-up of organic and inorganic matter,
and of the bacterial population. The layout of the system, the type
of coolers and the characteristics of the water used therein deter-
mine the required level of residual chlorine. The results of our
study show that a range of 2. 0 - 4. 0 ppm is normally adequate.
When these ranges of residual chlorine are constantly maintained in
the cooling water, bacterial population is not expected to exceed 100
colonies/ml in most cases. At this recommended max level of con-
tamination (3,6 ), occurrence of leaker spoilage is very unlikely
and bacteria of public health concern are seldom encountered.
Section 110. 80 of the GMP is another regulation that determines
the purpose for which cooling water could be reused (4 ). It states
that ". . . water shall not be reused for washing, rinsing or con-
veying food products in a manner that may result in contamination of
food products. " This means that cooling water containing chemicals
such as rust inhibitors and others, should not be reused for purposes
other than container cooling regardless of its good microbiological
quality ( 6 ).
Awareness of Potential Problems Pertinent to Certain Types of
Coolers;
Water samples collected from systems in which containers are cooled
exclusively in Still Retorts were of excellent bacteriological quality.
High TPC was encountered only when there was no detectable residual
germicide in the water. Container cooling in a still retort is a batch-
type operation. Therefore, the cooler is quite accessible for inspec-
tion and cleaning, and build-up of food residues inside the cooler is
easily avoidable.
•
The operation of Continuous Pressure Coolers is different. Circum-
stances may allow food residue from the exterior of filled, processed
cans to wash off and accumulate in the cooling water. Occasional me-
chanical jams which cause containers to burst within the cooler, pose a
major source of organic contamination of the cooling water. Over-lub-
rication of the moving parts of the cooler is another source of such a
contamination. The presence of organic matter in high concentrations
not only provides nutrients for bacterial growth in the cooling system,
but also reduces the germicidal effectiveness of the disinfectant, pre-
sent in the water, through chemical reactions. Reaction with chlorine
residues, for instance, is a good example. Furthermore, build-up of
suspended solids, whether organic or inorganic (especially in recircu-
lated water systems), affords bacteria a type of physical protection
131
-------
against the action of the germicide present in the water. Growth of
certain types of bacteria is also enhanced in these systems by the re-
latively high temperatures (120-140°F) especially in inadequately dis-
infected water.
When these conditions exist," leaker spoilage, especially of largest
and smallest can sizes, is frequently encountered. Therefore, it is
essential that continuous pressure coolers be drained, cleaned and
sanitized on a regular basis. Of equal importance is that an adequate
level of residual chlorine, or its equivalent, be maintained in the cool-
ing water in order to assure tight control of microbial growth in the
system.
In Hydrostatic Retorts, cooling water is normally recirculated within
the system (Fig. VII). After cooling, water returns to a basin lo-
cated either inside or outside the structure of the hydrostat. Cooling
water is then pumped to the spray nozzles inside the hydrostat's
cooling leg. The water in the basin is particularly prone to accumula-
tion of grease and oil, and build-up of bacterial population. This situa-
tion requires the continuous removal of the accumulated organic matter
and the maintenance of an adequate level of residual chlorine in the
water.
Surfaces within the cooling leg of the hydrostat should be inspected on
a regular basis. If heavy contamination is evident, surfaces should
be immediately cleaned and sanitized. Maintenance of an adequate
chlorine residual in the discharge may require direct injection of
chlorine into the basin. Chlorine requirements of the system must be
determined through a monitoring program in which microbiological
and other characteristics of the water are considered.
In various types of Spray Coolers, there is the potential for the ac-
cumulation of organic matter and microorganisms on the various sur-
faces within the cooler, (e. g. , belt conveyors - pans, etc.). Breakage
of glass containers, inefficient cleaning operations and inadequate
chlorination of the water are some of the most common causes of the
problem. When spray coolers are operated in the single-pass pattern,
the problem is more of an aesthetic nature. But if cooling water is
being recirculated, the quality of the water used to cool the containers
will be significantly affected by the conditions that exist inside the
cooler. Again, inspect, clean, sanitize and properly disinfect the
cooling water.
132
-------
u>
TO SEWCR.
Fig. VII. Cooling water system of a hydrostat.
-------
5. The Use of Cooling Towers;
It was not within the scope of this project to study in detail the vari-
ous types and designs of cooling towers. However, the following
guidelines, for the operation of container cooling systems with cooling
towers, are offered on the basis of the data acquired and observations
made.
(a) Proper application of chlorine (or other safe and approved
chemical) is indespensable. Chlorine should be applied to the
water feeding the coolers at a location that provides sufficient
contact time between chlorine and the water in order to enhance
the germicidal action of chlorine. Adequate mixing must also be
provided.
(b) Chlorine provision to the tower, itself, and the hot well must be
maintained. Periodical slugging of these components with con-
centrated chlorine solution is necessary to control the microbial
growth in the whole system.
(c) Residual chlorine levels in the water must be frequently moni-
tored at several points in the system, particularly at the hot well,
and chlorine dosage controlled so that adequate concentration of
residual chlorine is constantly maintained in the cooling water.
An automatic monitor/controller system is quite practical for this
purpose.
(d) When floor troughs are used to collect the discharge from coolers
and transport it to the hot well (sump), contamination from floor
washing and other clean-up operations must be avoided.
(e) Finally, the system must be drained, cleaned and sanitized on a
regular basis so that conditions of excessive chlorine demand
can be avoided and sources of microbial contamination elimin-
ated.
In conclusion, I'd like to emphasize the fact that the findings of this study re-
inforce NFPA's previous recommendation that a constant chlorine residual,
or its equivalent, is necessary to maintain sanitary conditions in cooling
water, particularly when the water is recirculated. Nevertheless, chlorina-
tion does not substitute for manual cleaning, proper container closure or
careful post-cooling container handling.
A CKNOWLEDGEMENT
The author gratefully acknowledges the cooperation of the food processors
who participated in this study and the laboratory assistance of Marcia Seeger
and Chris Merlo of the NFPA.
134
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REFERENCES
1. Doyle, E. S. Survey of Water Use in California. Proceedings of the NCA
Technical Sessions at the 45th Annual Convention. January, 1952.
2. Jacob, N. L. Container Cooling Water Systems - A Preliminary Survey
of Chemical and Microbiological Quality. Annual Report. NCA Research
Laboratories. Berkeley, California, pp. 50-52. 1976.
3. Jacob, N. L. Container Cooling Water Systems - An Overview of Chemical
and Microbiological Quality. Annual Report. NCA Research Laboratories.
Berkeley, California, pp. 29-34. 1977.
4. Katsuyama, A. M. Immediate Water-Savings Measures. Proceedings of
the Conference on Water Availability and Conservation. Oakland,
California. NCA-CLC. pp. 39-49. April 1977.
5. Standard Methods for the Examination of Water and Wastewater. 14th
Edition. American Public Health Association. Washington, D. C. 1975.
6. Townsend, C. T. and Somers, I. I. How to Save Water in Canneries.
Food Ind. Vol. 21, pp. W:ll-12. 1949.
7. White, G. C. Chlorine Dioxide. Handbook of Chlorination. Van Nostrand
Reinhold Co. , New York. pp. 596-627. 1972.
135
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LOW BOD RECIRCULATION STEAM BLANCHING
by
D. R. MacGregor* and P. Parchomchuk**
INTRODUCTION
The blanching operation is the largest single contributor to wastewater
BOD in a typical vegetable processing operation. Several workers have
modified conventional steam blanching methods to reduce BOD output by
various means. Water blanching, although widely used, does not seem to
possess the same possibilities for BOD reduction.
Among low BOD steam blanching systems which have been developed is the
hot gas blanching system of Rails et al. (1) which achieves very great
reductions in BOD while maintaining organoleptic quality and nutritive
value. Operating costs are generally higher than hot water er steam blan-
ching. A hot gas blanching process has been patented (2) in which steam
is added to the burning gas to prevent moisture loss from the product.
Forced circulation of the combustion gas-steam mixture gives a fluidized
bed effect.
Another system which significantly reduces BOD production in the blanching/
cooling process is the modified IQB method (3). This method reduces effluent
volume by reducing steam usage and by using atomized blancher condensate
to replace water in the air cooling section. The combination of IQB blan-
ching with air cooling has reduced COD production 50% and effluent volume
98.6% as compared to a conventional steam blanch with flume cooling. Prod-
uct quality is good but, even though liquid is added to the cooling air,
losses due to drying during cooling are large.
In a study by Lund (4) comparing different blanching methods for seven
canned vegetables, an average of 5.7 Ib of BOD were produced per ton
of material with conventional belt steam blanching compared to 4.4 Ib per
ton for IQB blanching. IQB blanching was found to be inferior to pipe blan-
ching for corn while for other products the blanching method had no signifi-
cant effect on product quality.
BACKGROUND
The object of the work being reported here is to remove from the waste
water stream all BOD produced in the blanching process in a commercially
feasible manner.
Since steam blancher condensate is essentially a dilute juice it seemed
that a modification of juice concentration technology could be used to
reduce blancher effluent to a compact concentrated form. Concentration of
juices by evaporation produces large quantities of steam which could then
be used for blanching.
* Food Processing and ** Agricultural Engineering Sections, Agriculture
Canada Research Station, Summerland, B. C.
136
-------
Juice concentrators normally use boiler steam to provide energy for evapora-
tion and steam generated is used in succeeding evaporator stages. In blanch-
ing, where the objective is to produce a maximum amount of steam, a somewhat
different approach is required. Also use of boiler steam to generate secon-
dary steam involves additional energy losses and capital costs. For these
reasons, it was decided to utilize a direct fired evaporator for generating
steam. In our original work several systems in which burning natural gas
was brought into direct contact with the blancher effluent were tried. These
were not successful because of the large ratio of non-condensible gasses to
water vapor and consequent lowering of condensation temperature.
STEAM GENERATOR UNIT DESIGN AND OPERATION
The final design, of which a pilot plant model was built and tested, con-
sists basically of a gas fired vertical tube and shell thermosyphon heat
exchanger (Fig. 1). Heat is transferred to the evaporator tubes from the
flame tube using oil (Essotherm N-69) as a transfer medium. The flame tabe
102 mm in diameter, and is baffled with 25 ram diameter oil filled cross-
tubes. The unit is surrounded by an insulated shell containing the heat
transfer oil and 17 evaporator tubes 12.7 mm dia. x 1220 mm long. This
gives a flame tube surface of 0.78 m2 and evaporator tube surface of 0.83 m .
Feed liquid enters through a manifold at the bottom and is carried up the
evaporator tube by the steam generated. Excess liquid is recycled and the
steam is fed to the blancher where it condenses on the material being blan-
ched and is returned to the steam generator. Provision is made by means
of a float valve for addition of make up water as needed. Non-volatile
materials leached from the product being blanched are concentrated in the
steam generator and bled off when a predetermined concentration is reached.
Bleed-off is controlled by a temperature sensor which responds to the
increased boiling point due to increased solids. An in line refractometer
would be somewhat more sensitive and much more expensive. A flow diagram
of the system is shown in Fig. 2.
For testing the unit, sufficient quantities of blancher effluent were
collected from commercial steam blanchers and either used immediately or
stored refrigerated at 2°C or frozen at -28°C until needed. The test blan-
cher consisted of a 20 cm x 120 cm stainless steel wire mesh belt with a
variable speed drive. Steam was delivered by a perforated pipe spreader
located between the upper and return section of the belt. The treatment
section of the blancher was enclosed in galvanized metal with rubber flaps
at inlet and outlet to allow product to pass without excess steam loss.
No special provisions, such as insulation, were made to reduce heat loss
from the blancher.
The general procedure for test runs was as follows: 1) commercial blancher
effluent was fed into the steam generator and the flame was started and
regulated to hold the temperature of the heat exchange oil at 190°C. 2)
steam from the generator was fed into the blancher and any condensate was
returned to the generator. Excess steam was allowed to waste. 3) when
solids in the generator had built up to a predetermined level (normally
70% T.S.S. by refractometer)the test vegetable was run through the blancher.
Blanching times were selected to give a negative peroxidase test. 4) feed-
137
-------
STEAM OUTLET
-BAFFLE
LIQUID RECIRCULATION
HEAT EXCHANGE TUBES
HEAT TRANSFER OIL
COMBUSTION CHAMBER
INSULATION
Fig. 1. Gas fired steam generator - concentrator prevents burning of
concentrated soluble solids by using intermediate heat transfer
oil to maintain low tube surface temperatures.
138
-------
EXHAUST GAS
J-k.
LIQUID-STEAM
SEPARATOR
STEAM
HEAT
EXCHANGER
TEMPERATURE
SENSOR
RAW PRODUCT IN
r
CONCENTRATE
BLEED
BLANCHER
NATURAL
LIQUID
RECIRCULATION
BLANCHED
PRODUCT
OUT
MAKE-UP WATER
RESERVOIR
Fig. 2. Heat exchanger vaporizes and recirculates effluent back to blancher while concentrating soluble
solids leached from product during blanching.
-------
ing in of blancher effluent and bleed off of concentrate continued. Total
running time with one product was up to 37 hr (over a five day period).
During steps (2), (3) and (4) propane consumption, steam production, oil
temperature, generator solids and stack gas temperature were monitored. In
addition during step (3), blanch temperature, time and product throughput
were measured. As well as heating the product with steam, exhaust gas at
150°C was discharged through a 35 cm section of belt to preheat the product
prior to entering the steam section.
The unit is operated with an oil temperature of 190°C. At this temperature
it generates 19.8 kg of steam/hr or 23.9 kg/m^/hr and uses 1.45 kg of pro-
pane per hr to give an operating efficiency of approximately 71%. The
temperature of 190°C is a compromise between capacity and 'burn on' in the
evaporator tubes. Recirculation of liquid in the generator is approximately
360 1/hr. This high recirculation rate helps to prevent burn on. Practical
blanching rate was in the neighbourhood of 60 kg/hr. Heavy loading tended
to reduce blancher temperature (the thermometer was located in the center
of the unit above the product). This represents a blancher efficiency of
only 39%, however, since our main interest was in the steam generator no
attempt was made to improve performance.
Blanching tests were conducted on asparagus, corn, diced carrots, cauliflower
and brussels sprouts. With all products except corn it was easily possible
to concentrate effluent in the steam generator to 70% total soluble solids.
Corn presented some problems in that the high starch concentration prevented
concentration beyond 40% and a fine precipitate (probably protein) which
tended to adhere to metal surfaces was formed. In spite of this no problem
was encountered with 'burn on'. Future plans include provision of a screen
to remove precipitates and particulate matter washed out of the blancher.
Blancher effluent contains some volatile aroma compounds which are returned
with the steam to the blancher. In addition some aromas are produced in
the steam generator. In order to test the possibility of off flavor transfer
to the material in the blancher, taste tests were conducted. Samples taken
from the same lot of vegetables were blanched in a laboratory steam blancher
and in the recirculation blancher, these were then cooled in water, packaged
in polyethylene bags and frozen at -28°C. After approximately one month
samples were cooked and presented to a ten member panel in a triangle test.
In this test panellists were asked to indicate preference for the single
or paired sample. No significant difference was found between treatments
or in acceptability.
In summary recirculation blanching shows real possibility for commercial
application. It has the following advantages:
1. All BOD involved in blanching is removed from the waste water
stream.
2. The unit can be installed adjacent to the blancher and is respon-
sive to fluctuating steam demands.
140
-------
3. Fuel efficiency is increased by elimination of heat losses from
boiler flue gases, steam pipes, etc.
4. It is a zero pressure system and does not require a stationary
engineer.
5. It is adaptable to present steam blanchers with the only modifica-
tions needed being in the steam distribution system.
6. It relieves boiler loading and will allow plant expansion without
the need for increased boiler capacity.
7. It reduces water consumption and energy costs associated with deli-
very of water.
8. The concentrate produced has potential use as an animal feed ingred-
ient.
It is hoped that a prototype capable of producing steam to blanch 1000 kg/hr
will be built and field tested for the 1979 season.
REFERENCES
1. Rails, J. W. et al. In-plant hot gas blanching of vegetables. Proc.
of the Fourth National Symposium on Food Processing Wastes, Syracuse,
New York, Environmental Protection Technology Series EPA 660/2-73-031.
(1973)
2. Smith, T. J. Dry blanching process. U. S. Patent 3,801, 715. (1974).
3. Botnben, J. L. et al. Integrated blanching and cooling to reduce plant
effluent. Proc. of the Fifth National Symposium on Food Processing
Wastes. Monterey, California. Environmental Protection Technology
Series EPA 660/2-74-058. (1974).
4. Lund, D. B. Impact of the individual quick blanch (IQB) process on
cannery waste generation. Proc. of the Fourth National Symposium on
Food Processing Wastes. Syracuse, New York. Environmental Protec-
tion Technology Series EPA 660/2-73-031. (1973).
141
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LAND VS ACTIVATED SLUDGE TREATMENT
OF POTATO PROCESSING WASTE WATER
by
K. Lynn Sirrine*
INTRODUCTION
A comparison of treatment systems is discussed for the treatment of potato
processing waste water. The intent of the paper is to present actual
problems associated with the treatment of potato processing wastes using
the activated sludge treatment method and the eventual conversion to land
treatment of these wastes.
BACKGROUND
The water pollution problem in some areas of Southeastern Idaho became very
critical during the winter and spring of 1960-61 at which time approximately
a quarter of a million fish were killed in the Milner Reservoir portion of
the Snake River. In addition to the fish kill, a septic condition was
created in the river and the water quality for domestic use was endangered.
The Snake River and its tributaries above the Milner Reservoir constitute
a major drainage system in Southeastern Idaho. Located along the banks
of the Snake River and its tributaries above the Milner Reservoir are numer-
ous municipalities and industries some of which discharged portions of their
waste into these streams. The capacity of this river system to tolerate
the waste disposal load placed upon it was reduced due to decreased water
in storage and increased use of these waters for irrigation. Because of
the waste load and the low water flow in the river, the aforementioned
pollution condition did develop and the State Board of Health requested
that all contributors try to do something to reduce the waste being dis-
charged to the streams. The potato processors of Idaho in the spring of
1961 immediately organized a committee which largely consisted of technical
personnel representing all of the major potato processing companies in the
State. This committee later became known as the Engineering Committee of
the Potato Processors of Idaho Association.
After making an extensive literature search and running a series of compre-
hensive laboratory studies, the Engineering Committee decided to verify their
laboratory findings in a full scale pilot plant waste treatment facility in
October of 1962. This study was operated until March of 1963.
* The R. T. French Company, Shelley, Idaho
142
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Since potato processing was a relatively new industry, very little infor-
mation was available concerning the treatability of potato waste material.
As a result, the industry encountered many different taxing problems which
required an all out effort to solve. This initial pilot plant study, which
was conducted at the R. T. French Company in Shelley, Idaho, was routinely
reviewed and visited by engineers and technical people from all over the
United States who were seeking information concerning our research work.
The Engineering Committee won the coveted "Air and Water Protection Award"
for 1963 by the presentation of a summary report on this study to the
Water Pollution Control Federation at a meeting in Seattle, Washington.
The Potato Processors of Idaho spent about $35,000 to $40,000 in time and
material on this primary treatment study which was completed in six months.
By November of 1963, all 15 potato processing plants located in the critical
area of the Snake River had installed primary treatment plants. The
installation of these plants decreased the potato processing pollution
load to the Snake River by about one half and cost the potato processing
industry in Idaho about 3 to 3.5 million dollars. In other words, the
potato processing industry quickly responded as responsible citizens of
Idaho to meet the State Board of Health's request for all contributors
of pollution to reduce their pollution load to the River. After com-
pletion of the primary treatment studies, work immediately began on
secondary waste treatment. The activated sludge treatment technique
appeared to give the highest degree of treatment on the potato processing
waste waters.
ACTIVATED SLUDGE
In 1968, a secondary waste treatment system was constructed under a
federal grant, being reported on in report number 12060EHV at the
R. T. French Company in Shelley, Idaho, 12/70, to treat potato processing
waste waters.(') About 50 to 60% of the waste water requiring treatment
came from the potato peeling operation.
Design factors for the activated sludge treatment system included two
aeration basins. Aeration Basin 1 holds 1.25 million gallons and normally
contains three 50-hp floating mechanical aerators. Aeration Basin 2 holds
2.5 million gallons and normally utilizes six 50-hp floating mechanical
aerators. Both basins have a water depth of 16 feet. The design BOD
loading is 28 lb/1,000 cu ft/day when the two aeration basins are operated
in parallel. The aeration basins are constructed of earth and were lined
with PVC (polyvinyl chloride). The bottom of the basins were sloped to
prevent forming pockets for entrapment of water or gas. A sun-resistent
Hypalon plastic sheet was placed around the perimeter of the basins to
protect the PVC from exposure to sunlight.
The secondary clarifier is 70 feet in diameter and has a 12-foot side
water depth. The clarifier has a rapid sludge withdrawal mechanism.
The hydraulic overflow rate is 325 gal/sq ft/day at the design flow of
1.25 mgd.
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SECONDARY TREATMENT FACILITY DESIGN FACTORS
INFLUENT PUMPS
Number
Type
Capacity
Each
Total
Total Head
Constant Speed
SLUDGE RECIRCULATION PUMPS
Number
Type
Capacity
Each
Total
Total Head
Constant Speed
WASTE SLUDGE PUMP
Number
Type
Capacity
Total Head
Speed
Dri ve
AERATION BASINS
Number
Type
Volume of Basin 1
Volume of Basin 2
Basin Water Depths
Basin Side Slopes
Basin Freeboard
Basin Lining
Number of Aerators, Basin 1
Number of Aerators, Basin 2
Design Organic loading
Centrifugal
1,300 gpm
2,600 gpm
27 feet
870 rpm
Centrifugal
435 gpm
870 gpm
18 feet
870 rpm
1
Positive displacement
100 gpm
46 feet
550 rpm
Variable - speed
2
Earthen
1.25 million gallons
2.5 million gallons
16 feet
2:1
2 feet
PVC with Hypalon cover in
sun-exposed area
3
6
28 Ib BOD/1,000 cu ft/d
AERATION EQUIPMENT
Number Aerators in Aeration Basins 9
Type Floating pump type mechanical
surface aerators with variable
oxygen transfer-power draw feature
Oxygen Transfer Capacity
75 pounds per hour each in
aeration basins with mixed liquor
suspended solids = 4,000 mg/1,
operating elevation = 4,627 ft. above MSL,
temperature at 20 degrees C.,
Alpha = 0.85, Beta = 0.90, and
operating dissolved oxygen =1.5 mg/1
144
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SECONDARY CLARIFIER
Number 1
Diameter 70 feet
Side Water Depth 12 feet
Mechanism Type Multiple port hydraulic suction
Design Flow 1.25 million gallons/day
Overflow Rate at Design Flow 325 gal/sq ft/day
Detention Time at Design Flow 7.2 hours
The plant was a modern plant utilizing mechanical floating aerators,
but did not have sludge wasting equipment. The plant was loaded at
an average load of 14,100 Ibs of BOD/day. D.O. levels of around
1 mg/1 were easily maintained. Even though the influent pH was rather
high (9.5 to 10.5) the pH buffered easily without the addition of
chemicals. The process water temperature ran about 21 C (70 F) and
was cooled to about 7.2 C (45 F) through operation of the aerators.
Numerous mechanical problems were encountered and we soon realized
that considerable maintenance attention was needed to keep the equip-
ment operational.
The major problem encountered with the activated sludge treatment
system was in the clarification of the mixed liquor suspended solids.
Low D.O. operation seemed to produce filamentous organisms that further
hindered the clarification process. As designed, the facility would not
meet the effluent requirements for discharge to the Snake River due to
suspended solids and BOD concentrations, although if the solids were
removed, the BOD would also be in exceptable limits. Even with these
problems, this plant won an award for design and for development of
operating parameters for activated sludge treatment of potato processing
wastes.
With the research study finished and the necessity for operation of
the facility with an effluent of good quality on a day to day basis,
it became evident that this system would require additional expenditures
to improve clarification of the mixed liquor. Also, proper sludge
handling equipment had to be added. We felt that changes and additions
to the facility would cost about $350,000 and after spending this much
we would still be faced with:
1. More stringent effluent controls in the future.
2. The possibility that clarification of the effluent could not be
accomplished at a reasonable cost.
3. Even with sludge handling equipment, we would have a residue to
dispose of.
4. Increased operating costs due to energy and labor.
5. Even more additions in the future.
LAND TREATMENT
An evaluation of various modifications to the activated sludge treatment
system was made. During these evaluations, it became more apparent that
145
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perhaps other treatment techniques should be looked into. One system,
land treatment, was receiving some success in the state. After an
evaluation of this technique, we found that we would be able to purchase
land, and install a land treatment system for less expense than modifi-
cations to the present facility. In addition to the reduced capital
expenditures, we also found that the operating costs would be less and
that a crop of grass hay could be taken from the land treatment system
which would further reduce our operating costs. Added to these benefits,
we would eliminate our waste water discharge to the Snake River.
Our Shelley land treatment facility consists of 164 acres of land
divided into 22 sub fields of about 7.5 acres. The land has been leveled
and graded to a specific grade, diked and seeded with a mixture of grasses.
The water is distributed over the land by a network of sub surface and
surface pipes. A peeler modification was made in the processing plant to
reduce the sodium concentration in the waste water. Waste water
characteristics are:
1. COD 3,000 to 4,000 mg/1
2. BOD/COD ratio 0.83
3. pH 6.5 to 7.5
4. Temp. 18°C (65°F)
5. Total nitrogen 100 mg/1 (as N)
6. Ammoniacal nitrogen 10 to 15 mg/1 (as N)
7. Nitrates 1 to 2 mg/1 (as N)
8. Iron 2 to 3 mg/1
9. PO. 5 to 7 mg/1 (as P)
10. Flow 1.15 MGD
Operation of the system is quite simple, as one sub field is watered for
24 hours. The fields are watered in rotation taking about 22 days for
a cycle, dependent upon weekend operation. Organically, we are loading
the land at about 175 Ibs of COD/acre/day. Nitrogen is about 5.8 IDS
of N/acre/day. We operate for about 230 days for a total organic load
of 40,250 Ibs/year and a nitrogen load of about 1,334 Ibs/year. We
harvest about 4 tons/acre of hay that runs about 13% protein. Howeve
most of the nitrogen is removed through denitrification in the soil.
COD removal is excellent, about 96% is removed after percolation through
6 feet of soil.
Cost Comparisons
Cost Activated Sludge Land Treatment
1. Labor, operation $14,200 $4,600
2. Labor, farm management — 22,000
3. Power 25,000 700
4. Maintenance
Labor 8,000 4,500
Parts 6,000 1,000
5. Solids Disposal Not constructed
6. Laboratory supplies 7,000 5,000
7. Operating supplies 4,000 500
Sub total 64,200 38,300
Income — 23,000
Total 64,200 15,300
146
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No cost data is available for the disposal of waste activated sludge
from the activated sludge plant. The estimated total investment for
the activated sludge system without the demonstration project was
$431,379 in 1968. This estimate does not include sludge wasting faci-
lities. Sludge wasting was estimated at $350,000, so the total plant
costs would have been around $780,000 in 1968.
The land treatment system cost $350,000, which included the cost of
the land. Peeler changes in the processing plant cost $160,000 for
a total investment of $510,000 (1973). The peeler changes also reduced
the organic load by about 30% and increased the amount of product being
sold as cattle feed from the primary waste plant. This increase only
amounted to about $6,000/year, which would not justify the peeler change
without the waste treatment need.
OPERATING PROBLEMS
The activated sludge system was a high maintenance plant. The more the
equipment added and operated, the higher the maintenance costs. The
floating aerator motors being the # 1 maintenance problem. Problems
are also encountered with too high a suspended solids concentration in
the clarifier effluent. The suspended solids separation being the # 1
operating problem. Under good conditions an exceptable effluent could
be achieved. However, seldom was the effluent quality good enough to
meet the discharge permit requirements. At times, odors from the facility
were offensive to nearby residents.
These problems can be overcome either through equipment additions or
modifications or through operation, chemical additions and etc.
Land treatment systems have to be designed for the hydraulic and
organic load placed on them. The water distribution system used affects
design with respect to field grading, etc. Assuming that the system
has been designed for waste treatment and is not merely a disposal
area, problems can still develop.
A poorly designed system will have problems with odors, insects, ponding,
poor percolation, poor water distribution, killing of grass, etc. A
well designed system may have problems with odors and water percolation
and build up during the winter operation in cold climates. The design
of the facility is more important than one might think. The odor
problem being the major problem, especially during the spring thaw
period of say March and April. Odors can be suppressed by chemical
additions, pipe line aeration and some changes in rotation of field used.
Good grass cover helps as does a green buffer of tall shrubs and trees
around the fields. Winter operating problems can be eliminated through
proper design considerations.
SUMMARY
An evaluation of our objectives concerning waste treatment revealed that
the activated sludge treatment facility was not giving us the service
147
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that we wanted. It almost seemed at times that we were no longer a
potato processor, but a waste treatment facility.
By taking a fresh look at the situation and by obtaining the views
of two outside consultants*, we were convinced that we were going
in the wrong direction.
Since regulatory agents and agencies are not defined for all time,
regulations change. A waste treatment facility must be designed with
enough flexibility that it doesn't become a burden on the owner and
that he is not continually burdened with expensive modifications,
additions and operation.
Land treatment of our potato processing waste water has given us the
flexibility and simplicity that we need. Some problems still exist
but are reasonable. Hopefully, the benefits of this type treatment
system to the food processor are seen by the regulatory people and
there use considered and not placed in jeopardy by new unnecessary
regulations.
Dr. Dale Carlson, University of Washington, Seattle, Washington
Dr. W. Wesley Eckenfelder, Jr., Vanderbuilt University, Nashville, Tenn.
REFERENCES
1. Aerobic Secondary Treatment of Potato Processing Waste Water
Pollution Control Research Series # 12060EHV 12/70
2. Staff Draft Report, National Commission on Water Quality,
November, 1975
3. Treatment of Potato Processing Waste Water on Agricultural Land:
Water and Organic Loading and The Fate of Applied Plant Nutrients
by J. H. Smith, C. W. Robbins, J. A. Bondurant and C. W. Hayden
Soil Scientists, Agricultural Engineer and Biological Technician
USDA-ARS-WR
Snake River Conservation Research Center, Kimberley, Idaho
148
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A DESIGN PROCEDURE FOR LAND APPLICATION
by
E.J. Kroeker*, A. Lamb*, and J.M. Haskill**
INTRODUCTION
Land application of wastewater began long before the development of today's
complex treatment plant techology. Use of effluent for a beneficial purpose
was reported in Germany in the sixteenth century and from that beginning the
application of sewage effluents to farmland was practiced in continental
Europe and England.
Land application approaches have a great deal of potential for alleviating the
wastewater management problems facing the food processing industry. The
problems become especially acute for those plants located in relatively small
communities whose municipal sewage treatment plants are not able to handle the
highly concentrated wastewaters usually produced by food processing plants.
Where land is readily available at reasonable cost, land application provides
an attractive alternative to wastewater treatment and disposal.
In addition to providing a means of wastewater renovation and removal, land
application provides a means of recycling nutrients and water through cover
crop irrigation and groundwater recharge. Land application disposal of waste-
water is also usually less energy intensive than today's mechanical treatment
processes.
Figure 1 summarizes the important steps in the selection, design and imple-
mentation of land application systems for wastewater treatment. This paper
will discuss various types of land application systems currently used for
treatment of various food processing wastewaters, mechanisms of wastewater
treatment in these systems and the importance of each of the major design
variables; it will conclude with a brief description of a design methodology
which should be followed in the selection and design of such systems.
METHOD OF LAND APPLICATION
Most land application systems used in the food-processing industry employ one
of the following surface application methods illustrated in Figure 2:
1. irrigation
2. overland flow
3. infiltration filtration
* Project Engineer and Director, Environment Division, Stanley Associates
Engineering Ltd., Edmonton, Alberta
** Program Engineer, Water Pollution Control Directorate, Fisheries and
Environment Canada, Ottawa, Ontario
149
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SMCinCATION OF
TREATMENT OBJECTIVES
L_ •• 1
PROCESSING- PL ANT
E"LU£NT CHARACTERISTICS
o) FLOW RATES
nl BOD a coo
e) T D S
e] s s
• ) N.P,
f) pH
g) TOXIC ELEMENTS
h) TEMPERATURE
i) BAOER'A / VIRUSES
|) PARISHES /INSECT VECTORS
») COLOUR
1 ) SAN
CLIMATE
CHARACTERISTICS
o) MONTHLY 01 SEASONAL
TEMPERATURE DISTRIBUTION
t) GROWING SEASON LENGTH
c) PERIOD Or FREEZING
«) DIRECTION a SPEED Of
PREVAILING WINDS
• ) TOTAL ANNUAL PRECIPITATION
fl MAXIMUM a MINIMUM
PRECIPITATION
|) RAINFALL DISTRIBUTION
H STORM INTENSITIES
i) TOTAL ANNUAL SNOWFALL
, ) SNOW DEPTH
t) DURATION OF SNOW COVER
SOIL - PLANT
SYSTEM CHARACTERISTICS
SOIL
• ) PERMEABILITY
b) INFILTRATION RATE
C) AVAILABLE WATER CAPACITY
4) CATION EXCHANGE CAPACITY
t) GROUNOWATER TABLE
PLANT
•) WATER REQUIREMENTS
• ) NUTRIENT REQUIREMENTS
c) TOLERANCE TO
TOXIC SUBSTANCES
«) MARKET VALCE
t) MANAGEMENT REQUIREMENTS
1 i
Fig
\ i
ECONOMIC ANALYSIS
] '
SPECIFICATION Of
CONSTRAINTS
o) ECONOMIC
» OPERATIONAL
C) ENVIRONMENTAL
1 1
IMPLEMENTATION
1 I
EVALUATION
ure 1. Flow diagram of the
decision making process.
CHOICE OF CATEGORY AND
METHOD OF LAND APPLICATION
i
PRE-TREATMENT REQUIREMENTS
|
COVER CROP SELECTION
t
LOADING RATE DETERMINATION
• ) HYDRAULIC
t) ORGANIC
C) NUTRIENT (N,P|
«) INORGANIC
|
SELECTION OF
LIMITING LOADING RATE
*
DETERMINATION OF
HYDRAULIC APPLICATION RATES
AND IRRIGATION SCHEDULES
t
DETERMINATION Of
BUFFER ZONE REQUIREMENTS
t
LAND-FORMING REQUIREMENTS
*
EFFLUENT COLLECTION
t
STORAGE REQUIREMENTS
*
DISTRIBUTION SYSTEM DESIGN
t
MONITORING REQUIREMENTS
150
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EVAPORATION
SPRAY OR
SURFACE
APPLICATION
ROOT ZONE
SUBSOIL
SLOPE
VARIABLE
DEEP
PERCOLATION
IRRIGATION
EVAPORATION
-GRASS AND VEGETATIVE LITTER
SHEET FLOW
r RUNOFF
I COLLECTION
OVERLAND FLOW
SPREADING BASIN
INFILTRATION
ZONE OF AERATION
AND TREATMENT
RECHARGE MOUND
SURFACE APPLICATION
PERCOLATION THROUGH
UNSATURATED ZONE
NEW WATER TABLE
/ III1 \
> HH X
OLD WATER TABLE
INFILTRATION PERCOLATION
Figure 2. Surface land application approaches,
151
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Irrigation
Irrigation is the controlled discharge of effluent, by spraying or surface
spreading, onto land to support plant growth. The wastewater is "lost" to
plant uptake, to air by evapotranspiration, and to groundwater by percolation.
Treatment of the wastewater generally occurs after passage through the first
60 to 120 cm (2 to 4 feet) of soil.
The method of application depends on the soil, the type of crop, the climate,
and the topography. There are three established methods of irrigation of
wastewater:
a) spray irrigation
b) flooding
c) ridge and furrow
These are illustrated in Figure 3.
Spray Irrigation
In the spray irrigation method, effluent is applied above the ground surface
by a sprinkler system in a manner similar to rainfall. The spray is developed
by the flow of effluent under pressure through nozzles or sprinkler heads.
The important components of a spray irrigation system are the pump, supply
main, laterals, risers and nozzles or sprinkler heads. The spray system can
be portable or permanent, moving or stationary.
Flooding
Flooding is the inundation of the land with effluent. The depth of inundation
is determined by the slope, choice of vegetation and the type of soil. The
land has to be level or nearly level so that a uniform depth can be maintained.
The land needs drying periods so that soil clogging does not occur and the
cover crop has to be able to withstand periodic flooding.
Ridge and Furrow Irrigation
Ridge and furrow irrigation is accomplished by gravity flow of effluent
through furrows, with subsequent seepage into the ground. Utilization of this
technique is generally restricted to relatively flat land, and extensive pre-
paration of the ground is required to create ridges and furrows whose width
and depth vary with the quantity of wastewater and the type of soil.
Although irrigation is the most common method of land application utilized,
its applicability to a particular location is most suitable if the following
site conditions exist:
1. Warm arid climates are ideal. More severe climates are acceptable if
facilities are provided to handle freezing and/or wet conditions.
2. Slopes up to 15 percent are acceptable provided runoff or erosion is
152
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RAIN DROP ACTION
' 4- — — "r T ---
--/tf:/\.rr.:. \ cr^
S"' ' ...•»... I ».. . • , *
~
irirrrrrrnTmT
SPRAY IRRIGATION
COMPLETELY FLOODED
' \ '. ••• -\
-^r ; V
FLOODING
^€?%jSi% --$^%^te^
»>*^ j/TV/'« .• >• ''.'f " \ ^ . '••'"•''. k ^is»
RIDGE a FURROW
Figure 3. Methods of irrigation.
153
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controlled.
3. Loamy soils are ideal but most soils from sandy loams to clay loams are
suitable.
4. Well-drained soil is required. Where these conditions do not exist the
site may be made suitable by incorporating underdrainage systems.
5. Soil depth of 1.5 to 2 m (5 to 6 feet) is required for plant root develop-
ment and wastewater renovation.
6. Geologic formations which may provide direct connection to groundwater
must be avoided.
7. A minimum depth to groundwater of 1.5 m (5 feet) is required to maintain
aerobic conditions, provide wastewater treatment and prevent surface
water-logging. Where this condition does not exist naturally, ground-
water pumps or artificial drainage may be used to lower the water table.
8. Typical land area required for a 4540 m per day (1 Imgd) irrigation
system is 40 to 80 ha (100 to 200 acres). Buffer zones are frequently
required for spray irrigation.
Overland Flow
Overland flow is the controlled discharge, by spraying or other means, of
effluent onto the land with a large portion of the wastewater appearing as
runoff. As the effluent flows down the slope a portion infiltrates into the
soil, a small amount evaporates and the remainder flows to collection channels.
Wastewater treatment occurs by filtration of suspended solids by surface
vegetation and by oxidation of the organic matter by the bacteria living on
the vegetation litter.
Soils limited in permeability such as clays and clay loams are especially
suited to overland flow. The land for an overland flow system should have a
moderate slope (between two and six percent) and the surface should have no
mounds or depressions.
The following conditions are necessary for a site to be especially suitable to
overland flow treatment of wastewater:
1. Soils with minimal infiltration capacity such as heavy clays, clay loams,
or shallow soils underlain by an impermeable subsoil are suitable.
2. A minimum topsoil depth of at least 15 to 20 cm (6 to 8 inches) is
recommended in order to establish a cover crop.
3. Slopes of 2 - 4% are required to allow the applied wastewater to flow
slowly over the soil surface to the runoff collection system.
4. Warm arid climates are ideal. More severe climates are acceptable if
154
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facilities are provided to handle freezing and/or wet conditions.
5. If reuse of the runoff is not possible, then a waterway or drainage
system must be constructed to transport the effluent from the site. This
effluent must meet the federal and provincial standards for discharge
into receiving waters.
6. A minimum depth to groundwater of 1.5 m (5 feet) is required to maintain
aerobic conditions for plant growth. Where this condition does not
exist naturally, groundwater pumping or under drainage may be used to
lower the water table.
7. Land requirements typically range from 10 to 45 ha (25 to 110 acres) for
a 4540 m^/day (1 Imgd) spray irrigation system; additional buffer zones
may be required.
Infiltration Percolation
The infiltration percolation method of wastewater treatment is similar to inter-
mittent sand filtration. The major portion of the wastewater enters the
groundwater although there is some loss to evaporation. Soils with high in-
filtration and permeability rates such as coarse textured sands, loamy sands
or sandy loams are required.
This process has been developed for groundwater recharge and thus the distinc-
tion between treatment and disposal for this process is quite fine. Some
treatment occurs during the infiltration percolation process as the wastewater
passes through the aerobic layer. The primary purpose of this method is to
provide physical removal of suspended solids and bacteria.
The applicability of infiltration percolation for land application treatment
of wastewater is quite restricted mainly because of soil permeability con-
straints. The following discussion summarizes the major criteria for the
suitability of infiltration percolation treatment:
1. Well-drained soils such as sand, sandy loams and loamy sands are required.
Very coarse sand and gravel are not ideal because they allow wastewater
to pass too rapidly through the first few feet where the major biological
and chemical wastewater treatment occurs.
2. A minimum depth to groundwater of 4.5m (15 feet) is recommended. Where
this condition does not exist naturally, groundwater pumping or artifi-
cial drainage may be used to lower the water table.
3. The site should be flat or gently sloping. Too much slope may create
lateral percolation.
4. Land requirements typically range from 1 to 2 ha (2.5 to 5 acres) for a
high-rate system to 8 to 24 ha (20 to 60 acres) for a low-rate system for
a 4540 m^/day (1 Imgd) wastewater application rate.
155
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TREATMENT MECHANISMS
The design and successful operation of any wastewater treatment plant is
predicated upon an adequate analysis of the wastewater being treated and upon
an understanding of the treatment processes to be employed. In land appli-
cation systems wastewater treatment and removal occurs at or below the soil
surface. The efficiency of treatment and removal is reflected by soil-plant
system characteristics, wastewater constituents and by the atmospheric climate.
Physical Processes
Many complex physical, chemical and biological processes take place to change
the characteristics of wastewater applied to a soil.
Filtering or retention of solids close to the soil surface is the major
physical treatment process. The size of particles removed is a function of
the soil pore size and configuration and of the nature of the particles in the
wastewater. The larger suspended solids are removed from the wastewater but
bacteria and viruses can travel considerable distances through soils. It
should be pointed out, however, that overloading with suspended material and
the subsequent creation of anaerobic conditions may have adverse effects on
the hydraulic capacity of the system.
The relative importance of soil physical processes in wastewater treatment and
removal is a function of the land-application technique:
1. In irrigation systems, water removal by the soil physical processes is as
important as the chemical and biological processes also taking place.
2. For overland flow methods of wastewater treatment, the soils are usually
quite impermeable and very little wastewater infiltration results.
Filtering of solids at the soil surface is therefore minimal.
3. In infiltration percolation systems, filtration of suspended organic matters
from the wastewater is a very important wastewater renovation process.
Chemical Processes
Two important chemical soil processes partially responsible for wastewater
treatment are adsorption and chemical precipitation. Soils containing clay or
organic matter attract and retain (adsorb) ions possessing a positive charge
(cations). The ability of the soil to adsorb cations is important to plant
growth and wastewater treatment. For example, important plant nutrients such
as potassium and ammonia which are usually present in significant concentra-
tions in wastewater can be retained on soil particles for adsorption and made
available for plant nutrition rather than leaching rapidly through the root
zone and eventually to the groundwater.
Chemical precipitation reactions involving dissolved ions and other chemical
compounds are numerous and exeedingly complex. Calcareous soils, common in
the prairies or in limestone-derived soils can neutralize acidic wastes
156
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although this may result in the release of relatively soluble salt solutions.
The principal mechanism for removal of phosphorus from wastewater in the soil
is chemical precipitation.
Biological Processes
The most important mechanisms of wastewater treatment in the soil involve
biological transformation. Some of the groups of soil organisms responsible
for the decomposition of plant and animal materials are bacteria, fungi, acti-
nomycetes, protozoa, worms and insect larvae. These organisms alter waste
constituents and a high proportion of the chemical constituents, notably carbon,
nitrogen, phosphorus and potassium, are liberated for'plant growth.
Aerobic decomposition of new organic material may be considered to take place
in three stages:
1. Organisms initially digest the more easily decomposed material, consuming
oxygen and releasing carbon dioxide and water. The amount of oxygen
consumed can be estimated by the five day biochemical oxygen demand test.
Organism growth rate is rapid during this stage.
2. The number of organisms declines as the readily decomposed organic mater-
ial is consumed. The dead microbial tissue, together with the intermed-
iate decay products provide substrate for new and remaining organisms.
This material, together with the more refractory organics in the waste-
water are degraded to a relatively stable end product known as humus.
3. The organisms decline to population levels similar to those before
addition of the wastewater. However, decomposition of humus by highly
specialized organisms continues during this phase.
The rate of organic matter decomposition and the nature of the intermediate
and end products depend on the composition of organic matter. Soil factors,
however, also exert considerable influence. The presence or absence of
adequate oxygen in the soil is the principal factor in determining the rate of
decomposition and the end products.
Decomposition also occurs under anaerobic conditions but at a slower rate and
often with the production of intermediate compounds having objectionable
odours. Plant growth will likely suffer under prolonged anaerobic conditions.
Intermittent or partial anaerobic conditions may result in the production of
nitrogen gas and various other gaseous oxides of nitrogen. This reaction and
the volatilization of ammonia can reduce problems of nitrogen overloading to
some extent.
DESIGN VARIABLES
Soil Characteristics
The foregoing discussion of physical, chemical and biological treatment pro-
cesses illustrates the interacting soil, cover crop, wastewater and climatic
157
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characteristics in wastewater treatment. Important soil characteristics in
the selection and design of land application systems include the following:
1. infiltration rate
2. permeability
3. available water capacity
4. cation exchange capacity
5. depth to groundwater
Infiltration rate is a soil surface phenomenon which describes the rate of
water movement into the soil surface. It is a direct function of soil pore
size and moisture content.
During initial wastewater application, the application rate is controlled by
the infiltration rate. The infiltration rate decreases, however, as appli-
cation continues and approaches a limiting value. At saturation, this con-
stant is equal to the permeability of the least permeable soil layer.
Most screening of suspended material from wastewater occurs during infiltration.
However, the high concentrations of suspended solids present in some food pro-
cessing wastewaters may clog surface soil pores. Application of wastewater at
rates beyond the infiltration rate for long periods of time results in anaero-
bic conditions.
Compaction of the soil surface by water droplets in a spray irrigation system
may greatly reduce pore space volume and seal the surface to downward water
movement. The presence of a cover crop to cushion the impact of water drop-
lets usually alleviates this problem.
Infiltration rate is an important variable in irrigation and infiltration per-
colation systems. Wastewater application rates which exceed infiltration rates
and thus produce ponding or surface runoff should be avoided. Periods of
wastewater application should be followed by rest periods to allow the surface
to dry and prevent the persistence of the anaerobic conditions which give rise
to surface clogging.
Permeability describes the rate at which water and air move through the subsoil.
It is controlled both by soil texture and structure and is primarily a function
of pore size. Fine textured and structured soils generally possess low per-
meability; medium textured and structured soils such as loam or silty loam tend
to have moderate to low permeability. Coarse sands exhibit the highest per-
meability. Table 1 summarizes typical permeability rates for various soils.
Those soils having severely restricted permeability in the lower part of the
profile are likely to develop a perched water table and tile drains may be
required. Soils having large pores or fractures transmit water and air rapidly
but may also transmit contaminants.
Conditions of extreme impermeability in the subsoil horizon may result from
layers of impervious clay beds or rock formations located within several feet
of the soil surface.
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TABLE 1. TYPICAL RANGES OF PERMEABILITY AND AVAILABLE
WATER CAPACITY ACCORDING TO SOIL TEXTURAL CLASS
Very coarse textured
sand and fine sands
Permeability (cm/hr)
0 to 3% 3 to 9%
2.5 or 2 or
greater greater
Greater
than 9%
1 or
greater
Available
Water Capacity
(cm/m)
4 to 8
Coarse textured loamy
sands and loamy fine
sands
2 to 4
1 to 2.5
1 to 2
6 to 10
Moderately coarse tex-
tured sandy loams and
fine sandy loams 1 to 2.5
Medium textured very
fine sandy loam, loams
and silt loams 0.8 to 2
Moderately fine tex-
tured sandy clay loams
and silty clay loams 0.5 to 1
Fine textured sandy
clays, silty clays
and clays
1 to 2
0.5 to 1
0.8 to 1
0.4 to 0.8
0.4 to 0.6 0.3 to 0.4
.3 to .5
.3 to .4
<0.3
10 to 15
13 to 20
15 to 20
13 to 20
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It is emphasized that the infiltration and permeability rates are important in
the selection of methods for wastewater treatment:
1. Soils with high infiltration and permeability rates are suitable for
infiltration percolation wastewater treatment.
2. Soils exhibiting very low infiltration and permeability rates can only
support overland flow systems.
3. Soils exhibiting moderate infiltration and permeability rates are suitable
for irrigation systems.
The available water capacity is defined as the amount of water retained by a
soil between the field capacity and the wilting point. Its magnitude deter-
mines the quantity of water which can be stored in the soil for uptake by
plant roots and it reflects the quantity of wastewater that can be held in
the soil without being discharged into the groundwater.
Available water capacity depends on soil pore size and shape and the strength
of bonding of the water to soil particles. Soils can be divided into three
groups, depending on the texture (typical ranges of available water capacity
are given in Table 1).
1. Coarse texture - low water capacity because of large pores and low sur-
face area; readily drained by gravity.
2. Medium texture - high available water capacity with relatively small
pores and medium retention of water.
3. Fine texture - low available capacity due to large areas and tightly
bonded water.
Cation exchange capacity is a measure of the ability of a soil to retain
positively charged ions such as the ammonium ion, calcium, magnesium, potasium
and sodium. Both the clay and humus fractions of the soil are characterized
by extremely small particle size and by the presence of a negative electrical
charge. The significance of this charge is that oppositely charged ions or
compounds are attracted and held to these colloidal surfaces. The size of the
soil colloids and the magnitude of the electrical charge determines the cation
exchange capacity of a soil.
The cation exchange capacity serves as a rough index of reactions which occur
between pollutants and the soil surfaces. In general, the greater the cation
exchange capacity of a soil, the greater the potential for effective waste
treatment.
The groundwater table is the level in the soil at which free water is present.
Above this level, free water movement is vertically downward. At the ground-
water table the soil becomes saturated and water movement becomes vertical
and lateral.
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The depth of the soil to groundwater is a major factor in determining water
storage and hence the surface water removal capacity of a land application
system. In addition, it determines the distance the wastewater will travel
through the aerobic zone where potential contaminants can be filtered out or
removed by biological and chemical mechanisms before the groundwater is reached.
The variation of depth to groundwater throughout the site and variation with
season should be determined prior to the selection of the site and the land
application method. In order to ensure an aerobic root zone for cover crop
growth, it is preferable to maintain a groundwater level at least five feet
below the ground surface. Groundwater levels can be controlled by installing
an underdrainage system or by pumping water from wells located close to the
site.
Cover Crop Characteristics
The cover crop increases the capacity of the soil to accept and to treat waste-
water. Plants protect the soil from erosion losses, encourage and maintain
moisture infiltration, increase soil drying rates through transpiration and
absorb nutrients. Vegetative cover also has an aesthetic appeal and may
contribute an economic benefit through crop harvest and sale. Cover crop
characteristics pertinent to the selection and design of land application
systems are the following:
1. water requirements
2. nutrient requirements
3. tolerance of the plant to potentially harmful wastewater characteristics
4. management requirements
5. market value
As discussed previously, some of the wastewater which is applied to the soil
is removed by natural drainage into and through the soil pore space. Plants
provide an additional means for water removal up to several feet below the
surface. Water moves into the plant roots and upwards to the plant body where
moisture is lost from the leaves by transpiration. The transpiration rate is
a function of climatic conditions including temperature, precipitation, solar
radiation and wind. It also depends on the availability of soil moisture and
on such characteristics as rooting depth and the seasonal pattern of root and
leaf development. The removal of water by both evaporation and transpiration
is described collectively as evapotranspiration. Important evapotranspiration
factors associated with the cover crop include rooting depth, seasonal pattern
of root and leaf development and other specific factors such as the physical
nature and size of leaf growth.
Rooting depth increases in importance as the length of the resting period in
the wastewater application schedule increases. As the surface layer of the
soil dries, water will be drawn from successively greater depths. Plants such
as alfalfa with deep rooting systems can also penetrate impermeable subsoil
zones and thus increase the water infiltration capacity of the soil.
Nutrient removal through crop harvest is the primary mechanism of nitrogen and
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phosphorus removal from the soil and depends on the type of land application
system. For example, in an overland flow system, both nitrogen uptake and
denitrification play major roles in nitrogen removal. Phosphorus removal,
however, is determined by plant uptake since adsorption by the soil is not
significant. In contrast, the quantity of nutrients removed by plants may
be minor compared to total loadings in an infiltration percolation system.
The quantity of nutrients which can be removed depends on the type of plant
cover and the harvested yield. Figure 4 illustrates the potential for
removal of nitrogen and phosphorus in various crops. Both nitrogen and
phosphrous are absorbed in greatest quantities by certain species of grasses.
Harvesting the entire cover crop (for example, corn silage, hay) results in
greater nutrient removal than harvesting only selected parts (grain, vegetable
crops) and ploughing the remaining vegetation into the soil.
Certain chemical constituents of wastewater may be toxic to vegetative growth.
The elements of possible concern in food processing wastewaters include
sodium, calcium and magnesium, and various salts such as chloride, sulfate
and bicarbonate.
The effect of saline solution on plant growth is principally due to changes
in the osmotic pressure of the solution which influences water availability
to the plant roots. In addition, high concentration of ions such as chlorine
may interfere with nutrient assimilation by plants. Plant species differ in
their responses to salinity.
The ability of the cover crop to adapt to a specific land application system
and the labour requirements for successful crop management are important
factors in selecting a cover crop. The following factors need to to be taken
into account:
1. Tolerance to variable soil moisture conditions, especially frequent
saturation.
2. Soil physical and chemical properties.
3. Tolerance to severe climatic changes such as low temperatures and the
plant growing season.
Assistance in the selection of crops can normally be obtained from local
agricultural representatives.
Labour requirements for successful crop management may be critical during all
stages of crop growth. These include germination, emergence, and seedling
establishment in which favourable soil and moisture conditions are critical
for some crops.
During the growth period, important management factors may include supplement-
al fertilization, well defined tillage practices, irrigation scheduling, weed
and insect control and crop harvesting. It may also be necessary to re-estab-
lish or rotate crops from to time when visual checks or yield tests indicate
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CORN GRAIN
WHEAT GRAIN
CORN SILAGE
ORCHARD GRASS
BLUEGRASS
FESCUE
REED CANARY GRASS
100
200
300
NITROGEN REMOVED IN HARVEST (kg/ha-yr.)
CORN GRAIN
WHEAT GRAIN
CORN SILAGE
ORCHARD GRASS
BLUEGRASS
FESCUE
REED CANARY GRASS
10
20
30
PHOSPHORUS REMOVED IN HARVEST (kg/ha-yr.)
Figure 4. Potential nutrient removal by crops.
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poor productivity. Specific cover crop requirements and limitations are
discussed later in this section.
The economic return from certain crops may offset some of the operating costs
of a land application system. The return may be substantial in arid regions
because the availability of water permits the growth of crops not otherwise
possible. In such areas, limited competition in local markets may add signifi-
cantly to this monetary return.
The following cover crops have been used in land-application systems:
1. Small grains, such as wheat, oats and barley
2. Row crops such as corn, sugar beets and vegetable crops
3. Sod crops, primarily grasses and legumes
4. Forests
Wastewater Characteristics
Wastewater characteristics may affect the selection of land application methods
and they will usually affect the efficiency of operation of such a system.
Wastewater characteristics which should be determined prior to the design of a
land application system are the following:
1. Annual and seasonal wastewater quantities
2. Biochemical oxygen demand (8005) and chemical oxygen demand (COD)
3. Suspended solids (SS)
4. Total dissolved solids (TDS) and electrical conductivity (EC)
5. Nitrogen (N)
6. Phosphorus (P)
7. pH
8. Temperature
9. Color
10. Toxic elements (heavy metals, trace elements, etc.)
11. Bacteria and viruses
12. Sodium adsorption ratio (SAR)
13. Oil and grease
The seasonal and annual quantities of wastewater generated by a processing
plant will determine the area of land required to dispose of the wastewater.
In addition, since wastewater produced during the winter months will usually
have to be stored, quantities generated during those months will determine
storage volume requirements.
The biochemical oxygen demand (6005) is a measure of the concentration of
readily oxidizable organic matter in the wastewater. When the rate of appli-
cation of organic matter exceeds its rate of removal by soil micro-organisms,
clogging of the soil surface may result,thus greatly reducing the wastewater
infiltration rate and producing anaerobic conditions within the soil which
greatly decrease the efficiency of treatment.
Suspended solids in wastewater may cause operational problems such as clogging
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of sprinkler nozzles and soil pores, and the formation of an impermeable
coating over the soil surface.
An excessive rate of application of high IDS bearing wastewaters may cause a
salinity hazard to crops and/or may cause groundwater contamination. The
salinity hazard to crops can be especially prevalent in arid or semi-arid
regions where the annual evapotranspiration exceeds annual precipitation.
Table 2 summarizes some of the effluent quality requirements for land appli-
cation systems.
Nitrogen and phosphorus may be present in relatively high concentrations in
some wastewaters, especially those from meat and poultry processing plants.
Although both are important plant nutrients, when applied at excessive rates,
they may contaminate the groundwater.
Wastewaters having a pH between 6.0 and 9.0 are generally suitable for appli-
cation to the land since microbial and plant processes are generally most
active in the neutral pH range (6 to 7).
The application of high temperature wastewater (greater than 150 F) to land
may sterilize the soil and thus prevent the growth of any vegetation.
In most wastewaters colour is associated with degradable organic material and
is effectively removed as the water percolates through the soil mantle. How-
ever, should the colour associated with the wastewater be persistent such as
that associated with lignins, it can leach into the groundwater and effective-
ly contaminate this water source. This type of groundwater contamination is
difficult to avoid and therefore coloured wastewaters to be applied to the
land should be carefully assessed for ease of colour removal.
Meat and poultry processing wastewaters usually contain significant concen-
trations of pathogenic bacteria and viruses. Although the soil mantle is
usually quite efficient in the removal of bacteria and viral organisms, some
concern has been expressed recently because of confirmed viral infection
resulting from land application of wastewaters. When a spray application
system is to be utilized, consideration should be given to the possible trans-
portation of pathogens in aerosols.
The relationship between the principal cations in wastewater, especially
calcium, magnesium and sodium is very important. When the ratio of sodium to
calcium and magnesium (expressed as sodium adsorption ratio) becomes too high,
the sodium tends to replace the calcium and magnesium ions on clay particles
and has the effect of dispersing the soil particles and consequently reducing
soil permeability.
Wastewaters from meat and poultry processing plants usually contain relatively
high concentrations of oil and grease from cutting, deboning and rendering
operations. Excessive concentrations may cause severe clogging of the soil-
pores.
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TABLE 2. EFFLUENT QUALITY GUIDELINES
(3)
Problem and
Related Constituent
No Problem
Guideline Values
Increasing Problems
Severe
Salinity
EC of irrigation
water, in mmho/cm
Permeability
EC of irrigation
water, mmho/cm
SAR (Sodium ad-
sorption ratio)
Specific ion tox-
icity2
From root adsorption
Sodium (evaluate
by SAR)
Chloride, me/1
Chloride, mg/1
Boron, mg/1
From Foliar
adsorption
(Sprinklers)
Sodium, me/1
Sodium, mg/1
Chloride, me/1
Chloride, mg/1
less than 0.75 0.75 to 0.30
greater than 0.5 less than 0.5
less than 0.6 6.0 to 9.0
less than 3.0
less than 4.0
less than 142.0
less than 0.5
less than 3.0
less than 69.0
less than 3.0
less than 106
3.0 to 9.0
4.0 to 10
142 to 355
0.5 to 2.0
greater than 3.0
greater than 69.0
greater than 3.0
greater than 106.0
greater than 3.0
less than 0.2
greater than 9.0
greater than 9.0
greater than 10
greater than 355
2.0 to 10.0
1 Assume water for crop plus needed water for leaching requirements will be
applied. Crops vary in tolerance to salinity.
2 Most tree crops and woody ornamentals are sensitive to sodium and
chloride (use values shown). Most annual crops are not sensitive.
3 Leaf areas wet by sprinklers (rotating heads) may show a leaf burn due to
sodium or chloride adsorption under low-humidity, high-evaporation con-
ditions. (Evaporation increases ion concentration in water films on
leaves between rotations or sprinkler heads).
Note: Interpretations are based on possible effects of constituents on crops
and/or soils. Guidelines are flexible and should be modified when
warranted by local experience or special conditions of crop, soil, and
method of irrigation.
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Climatic Characteristics
The magnitude of climatic effects in the design of land application systems
depends on the category and method of application, the type of equipment used
and the volume of wastewater applied. The major climatic variables are the
following:
1. Seasonal and annual distribution of precipitation
2. Average seasonal temperatures
3. Speed and direction of prevailing winds
Precipitation in the form of rainfall, snow and hail will serve to determine
allowable wastewater loading rates, storage requirements and land drainage
requirements.
During the application season, the land area must be sufficient to dispose of
incident seasonal precipitation as well as of applied wastewater. Therefore,
a water budget for a proposed system must take account of all precipitation
during the wastewater application period. All storage facilities must be
sufficient to contain any incident precipitation and runoff produced during
non-application periods.
The ambient air temperature affects wastewater loading rates and determines
the allowable length of the application season. The rates of soil microbial
reactions are temperature dependent. The rate of removal of water from the
soil and cover crop by evapotranspiration is a function of several variables
including precipitation, wind, availability of soil moisture and vegetation
characteristics. However, temperature is the single most important variable.
Finally, cover crop growth patterns are controlled as much by temperature as
by moisture availability.
The prevailing wind directions and speed are important where spray irrigation
is used and aerosol drift to nearby communities may be a problem. These wind
data are useful in predicting buffer zone requirements around the wastewater
treatment facility. In addition, prevailing wind direction should be con-
sidered where odour transmission is a potential problem, particularly from
stored effluents.
PROCESS DESIGN
Figure 1 summarizes the various steps in the design of a land application
system. Following a preliminary assessment of site characteristics and con-
straints, one of the three methods of land application discussed earlier
should be selected. This section summarizes briefly the various design
components for each of the systems.
Pretreatment Requirements
Pretreatment requirements for food processing wastes may include one or more
of the following processes:
167
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1. Coarse screening for suspended solids removal
2. pH adjustment
3. Deodorization
4. Biological pretreatment
Coarse screening may be required for removal of solids which clog spray
nozzles or for the removal of grit which may accelerate the erosion of pumping
and transmission equipment.
The three types of screens normally used include stationary, vibrating and
rotating screens.
pH adjustment is required for those wastewaters whose pH is outside the range
of 6 to 9.5. Typical chemicals used include sodium hydroxide and sodium
carbonate for acidic wastewaters, and sulphuric and hydrochloric acid for
alkaline wastewaters.
Wastewater effluent may be deodorized prior to irrigation in those cases where
odour problems exist.
Biological pretreatment may be required by the provincial regulatory agency
involved in approving the facility. Biological treatment processes which have
been used include anaerobic lagoons, facultative and aerated lagoons, acti-
vated sludge, oxidation ditches, trickling filters and rotating biological
contactors.
Cover Crop Selection
The choice of a suitable cover crop will depend on one or more of the following
objectives:
1. Maximum water removal
2. Nutrient removal
3. Economic return
Sod crops such as legumes and grasses have a longer growing season than grain
or row crops and therefore provide increased consumptive use of water. Forests
also hold the potential for removing relatively large volumes of water.
Sod crops, row crops and grain crops provide good nutrient removal. Grain
crops and row crops may be used to maximize the economic benefits of a land
application facility.
Loading Rate Determination
The importance of regulating the liquid loading rate, the effects of over-
loading and the climatic constraints to seasonal and annual wastewater
application rates were discussed earlier. Soil permeability and climatic
evapotranspiration data should be used to determine the hydraulic loading
rates for the site. These rates can then be used to determine land areal
requirements and to set up an irrigation schedule.
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The wastewater application rate may be limited by the concentration of nitrogen
and/or phosphorus in the wastewater. The nutrient loading rate to the soil
must be limited such that a balance is reached between the amount applied, the
amount removed by treatment and crop uptake and the concentration permitted to
reach the groundwater.
The effects of organic overloading to the soil were discussed earlier. Waste-
water application rates should not be so high that clogging of the soil surface
occcurs due to excessive organic application rates.
In most cases either the hydraulic or the nutrient loading rate to a particular
soil will determine the allowable wastewater application rate. Once the rate
has been established, an application cycle is determined. Application rates
are normally expressed as the quantity of wastewater applied per cycle. The
duration of the wetting or application period and the application rate during
each cycle are determined by the method of application used. Resting or drying
periods following the wetting period are usually necessary to re-establish
aerobic conditions in the soil. The optimum drying period is a function of
the land application method and is also very site specific.
Buffer Zone Requirements
When a spray irrigation facility is located near populated areas, a buffer
zone is recommended, especially downwind of the sprinkler. In some cases,
this may involve scheduling the location of application such that the buffer
zone downwind of the application site is a portion of the field.
In other cases, buffer zones from 15 to 60 m wide around the perimeter of the
site have been utilized. Provincial regulations may require buffer zones in
excess of these.
Land Forming Requirements
Land forming requirements are usually minimal for spray irrigation but are
important in flood irrigation and ridge and furrow irrigation systems.
Formation of basins is usually required for infiltration percolation systems
and surface alterations may be required in overland flow systems to provide
adequate slope and soil surface characteristics.
Underdrainage Effluent Collection
A subsurface drainage system may be required to prevent excessive groundwater
buildup or to intercept the effluent and collect it for further treatment
prior to discharge.
Storage Requirement
Storage of wastewater may be required under one or more of the following
conditions:
1. Seeding and harvesting the cover crop
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2. Precipitation requiring the temporary reduction or cessation of
application
3. Winter weather requiring reduction of winter application rates
4. Winter weather requiring cessation of operation
When reduction or cessation of operation resulting from winter weather is
expected, storage requirements should be based on the maximum expected
freezing period. Temporary wastewater storage may be necessary during the
application season when excessive rainfall prohibits normal application. The
size of the storage basin must be sufficient to contain anticipated precipi-
tation during the storage period in addition to the wastewater.
Distribution System Design
The distribution system consists of facilities for transmission to the site
and facilities for application at the site including pumps, distribution mains
and laterals, flow control valves and outlets such as sprinklers for spray
irrigation systems or gates for flood irrigation.
Transmission to the site can be by pressure or gravity. Velocities in the
transmission main should be between 2.5 and 3 metres per second. Gravity
mains should be at the low end of the range and force mains should be in the
middle to upper range. Where velocities are too high, excessive losses occur
at bends and valves.
The distribution system is the most complex component of any land application
facility; its design will not be discussed in this paper. Irrigation handbooks
such as that by Pair^) provide the pertinent hydraulic design information.
Monitoring Requirements
A monitoring program may be required to ensure that proper wastewater treat-
ment is being carried out and that environmental degradation is not occurring.
Secondly, monitoring of the cover crop may be useful to optimize its growth
and yield. Finally, since application of wastewater to land is likely to
cause some changes in soil characteristics, periodic monitoring of soil
salinity levels, pH and cation exchange capacity should be practiced.
LABORATORY AND PILOT EXPERIMENTS
Laboratory and/or pilot plant experiments can be useful in investigating some
of the technical aspects of the application of wastewater to land. Although
considerable information can be obtained from these studies, caution is
advised since the experimental conditions may be somewhat artificial. Green-
house germination tests or growth chamber tests and onsite pilot scale studies
can all be used as part of the predesign activity to assess the practicality
of land treatment for a specific site.
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Germination tests may be useful to detect potentially acute toxicity
resulting from the application of wastewater. The test is a comparison of
germination of seeds in soil moistened with wastewater to that in soil
moistened with tap water.
Greenhouse experiments are used to assess plant responses to the application
of wastewater. These experiments may be carried out by comparing plant
growth from wastewater application with that from tap water application.
The plant tissue and soil can be subjected to chemical and physical analyses
after harvesting.
These experiments require facilities for plant growth and analysis, and
several months of laboratory or greenhouse experimental time.
Onsite pilot studies can provide valuable design data (wastewater application
rates and soil capacities), particularly where the topography and soil type do
not clearly favour one category of application over another.
Pilot studies should be conducted on representative plots, approximately 0.5
hectare in area. Flat plots may be defined by plowing a furrow around the
perimeter and mounding the soil around the edges. Sloping plots suitable for
overland flow systems will require a cleared ditch with a flow-measuring
device (Parshall flume or V-notch weir) at the base of the slope. A network
of wellpoint piezometers should be installed in and around flat areas and
those sloping areas with high permeability to monitor changes in water table
and groundwater quality.
CONCLUSION
For most land application systems, a wide range of design possibilities is
available to suit specific site characteristics, climate, treatment require-
ments, and project objectives. In addition, a wide range of design possibil-
ities is available for each site. The designer must rely on a comprehensive
understanding of the treatment principles involved, site evaluation by
specialists and his own ingenuity. When proper attention is given to the
design of such facilities, land application systems hold a great deal of
potential for the treatment of effluents from food processing plants since
these wastewaters are generally non-toxic and easily biodegradable.
ACKNOWLEDGELMENTS
The material presented in this paper was prepared under a Department of Supplies
and Services Contract (No. OSS76-00225) for the Abatement and Compliance Branch,
Water Pollution Control Directorate, Fisheries and Environment Canada, Ottawa.
The authors also acknowledge the cooperation of the food-processing industries
that contributed valuable operational data for preparation of the design manual
from which this paper has been abstracted.
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LIST OF REFERENCES
1. Powell, G.M., 1975. Design factors - Part II. Prepared for the design
seminar for land treatment of municipal wastewater effluents, US EPA
Technology Transfer, New York City.
2. Jewell, W.J., R.C. Loehr, J.D. Novak, E.L. Stone. Role of vegetative
cover In: Education Related to the Land Disposal of Wastes. EPA
Project T-900500, Washington, D.C., August 1976.
3. Ayers, R.S., 1973. Water quality criteria for agriculture. UC -
Committee of Consultants. CWRCB.
4. Pair, C.H. (Ed.), 1969. Sprinkler irrigation. 3rd Edition, Sprinkler
Irrigation Association, Washington, D.C.
5. Stanley Associates Engineering Ltd., 1976. Design and operations manual -
land application of food processing wastewater. Prepared for the
Abatement and Compliance Branch, Food and Allied Industries, Environmental
Protection Service, Ottawa.
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USING MICROWAVES TO REDUCE POLLUTION FROM SCALDING CHICKENS
by
B. F. Miller*, S. A. Kula*, J. W. Goble**, and H. L. Enos*
The traditional method of achieving feather release of poultry in the slaugh-
tering process is by scalding, which consists of applying moist heat to the
skin to reduce the force required to pull the feathers. It is usually accom-
plished by immersing birds in or spraying them with water at temperatures
ranging from 54°C for broiler chickens up to 60°C for fowl and turkeys. The
objective is to loosen the feathers to permit their removal by mechanical
pickers.
Research by Gwin(l) (2) (3) indicated marked advantages for scalding in
reducing labor costs of pinning and in assuring a completely feather-free
bird. Pool et al.(4) investigated the effects on feather release when live
birds were injected with reserpine. The force required to pull the feathers
from the treated birds was impressively reduced after 18 hours, but the pre-
injection force required returned almost immediately after the birds' death.
Other methods were also studied, including the effects of radiant heat, brain
sticking, and administration of sodium barbitol. Klose(5) suggested that
aesthetic and product safety considerations encourage the replacement of
immersion-type scalding; however, the development of commercially feasible
alternatives has been hampered by economic and engineering problems. Alter-
natives that have been considered include spray or steam scalding and a
combination of the two.
The major limitations of the scalding method are: (a) the large quantity of
water required (about one quart per bird); (b) the amount of energy necessary
to heat the water (about 200 BTU's per bird); and, (c) the process involved
in disposing of the polluted water that results.
Increasing attention has been directed to these limitations because of rapid-
ly escalating costs of energy, the increasing scarcity of potable water,
societal concerns for environmental quality, and consumer interest in product
quality. Thus, a need exists to find an alternative system that avoids the
shortcomings of the scalding method for achieving feather release. After
Miller(6) used a home microwave unit, he concluded that the method might be
feasible to achieve feather release but the results were inconsistent.
The purpose of this study was to investigate further whether exposure of
broilers to microwave energy would release feathers satisfactorily from the
different feather tracts and whether, as a consequence, underlying tissue
would be adversely affected.
*Department of Animal Sciences, Colorado State University, Fort Collins,
Colorado 80523
**Agricultural Research Service, U.S. Department of Agriculture, Beltsville,
Maryland 20705
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PROCEDURE
Broiler chickens ranging in age from 8 to 12 weeks were used in this experi-
ment. Of the 242 broilers used, 233 were treated with microwave energy.
They were assigned a random number from 1 to 20, representing predetermined
exposure -times. The nine remaining birds served as controls: five of them
were scalded by immersion in hot water and four were untreated.
The control group treated by scalding was immersed in water at a temperature
of 61°C for about 1.5 to 2.0 minutes. Then an incision was made in the
feather tract, and a thermometer was inserted to measure the tissue tempera-
ture. The force necessary to pull the feathers as a consequence of scalding
was measured with a Dyne-Newton scale equipped with a clamp on the end of a
rod that was attached to a feather or group of them. As the bird was pulled
manually away from the scale at a uniform rate, the scale moved a relatively
friction-free pin around the dial. When the feather was released, the dial
needle that indicated the force quickly returned to zero, leaving the fric-
tionless pin stationary at the point of maximum force.
From the data on the control group of birds treated by scalding, the maximum
force acceptable to achieve feather release was determined to be 3.5 Newtons.
This measurement was used as an evaluative criterion for the effectiveness
of microwave treatment.
The birds treated by microwave energy were placed in a commercially available
unit that had a 0.9-meter cubicle chamber containing a carousel-type mode
stirrer to provide uniform exposure. The unit also contained a power meter
to register the amount of energy that entered the chamber at any given time.
The birds were exposed individually by suspending them by the feet from a
plastic shackle in the microwave chamber. Each one was subjected to micro-
waves for the specified assigned time at a fixed power level for its respec-
tive treatment group. The power levels selected were 500, 1500 and 2000
watts. Exposure times ranged from .25 to 2.0 minutes at .25-minute intervals.
Upon completion of the microwave treatment, the temperature of the tissue and
the pulling force required to remove the feathers were determined for each
bird by the same procedure that was used for the scalded control birds. The
feather release force was measured for each of the feather tracts (e.g.,
humeral, alar, ventral, spinal, femoral, crural, and caudal). Tissue damage
was determined by a visual examination of underlying tissue after exposure.
A discriminate analysis was statistically performed to distinguish between
feather release versus non-release and tissue damage versus no damage.
RESULTS AND DISCUSSION
After the first 20 birds were exposed to microwaves, it was found that the
power necessary to achieve satisfactory feather release from femoral, spinal,
and ventral tracts caused extensive tissue damage to the alar, caudal,
crural, and humeral feather tracts. These findings suggested that the
feather tracts required different levels of power and times for satisfactory
174
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feather release. A second group of 20 birds was similarly treated to provide
sufficient data for statistical analyses. The Student t test was used to
statistically analyze the data for each feather tract. The alar, caudal,
crural, and humeral feather tracts evidenced no significant differences in
the time or power level necessary for feather release without tissue damage.
Similarly, it was found that the femoral, spinal, and ventral feather tracts
had the same relative time and power requirements among themselves. The find-
ings necessitated that the feather tracts be considered as two separate
groups; one consisting of the alar, caudal, crural, and humeral (extremities)
and the second consisting of the femoral, spinal, and ventral (torso).
The number of power levels originally planned also had to be reduced, Only
the 1500- and 2000-watt levels were used for the remaining 193 birds because
the 500-watt level was found to be ineffective, and the 2500-watt level was
unattainable with the particular microwave machine that was used. The orig-
inal exposure evaluation techniques were also modified to make judgmental
decisions about feather release effectiveness and tissue damage resulting
from microwave exposure. These decisions were made by comparing the effort
required to pick feathers from each bird before and after exposure. Question-
able results were verified with the Dyne-Newton scale. Visual examination
for determination of tissue damage was continued.
The results from microwave exposure were classified into four treatment cate-
gories: Treatment 1 - the femoral, spinal, and ventral feather tracts
exposed to 2000 watts of power; Treatment 2 - the alar, caudal, crural, and
humeral feather tracts exposed to 1500 watts; Treatment 3 - the alar, caudal,
crural, and humeral feather tracts exposed to 2000 watts; and Treatment 4 -
the femoral, spinal, and ventral feather tracts exposed to 1500 watts.
The treated birds were further classified into three groups by discriminate
analysis (Table 1): Group 1 - underexposed, with no feather release or
tissue damage; Group 2 - optimum exposure, with feather release and no tissue
damage; and Group 3 - overexposed, with feather release and tissue damage.
The findings indicated that satisfactory feather release can be obtained by
exposing a bird to a predetermined level of microwave energy for a predeter-
mined time. However, the alar, caudal, crural, and humeral feather tracts
must be exposed for less time than the femoral, spinal, and ventral feather
tracts. The problem is that the microwave unit cannot properly distribute
the energy over a bird's body due to the unequal mass distribution of the
bird. Theoretically, exposing the torso for a predetermined amount of time
while shielding the extremities to prevent them from being cooked, then sub-
sequently exposing the entire body to the microwave level necessary to release
feathers from the extremities would be ideal. Such a procedure would permit
all of the feathers to be released without any tissue damage.
From the data generated, equations were developed through discriminate analy-
sis whereby, if a bird's weight is known, the time exposure to microwaves
that would be necessary to achieve feather release at a constant power for
each of the two groupings of feather tracts can be calculated.
175
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TABLE 1. SUMMARY OF MICROWAVE EXPOSURE DATA ON CHICKENS
ON
Feather
Treatment Tract
No. Group*
1 1
Total or Avg+
2 2
Total or Avg+
3 2
Total or Avg"1"
4 1
Total or Avg4"
Total
Birds
No.
14
23
18
55
20
18
22
60
18
19
20
57
4
6
11
21
Weight per Bird
Kg
2.22
2.13
1.95
2.09
2.32
2.27
2.18
2.22
2.18
2.38
2.18
2.27
2.22
2.18
2.09
2.13
Std
Dev
0.59
0.50
0.57
0.58
0.53
0.62
0.52
0.56
0.82
0.57
0.61
0.70
0.72
0.30
0.22
0.37
Microwave
Power
(Watts)
2000
do.
do.
1500
do.
do.
2000
do.
do.
1500
do.
do.
Exposure Time (Min)
Avg
0.58
0.70
0.90
0.74
0.37
0.53
0.77
0.58
0.29
0.47
0.60
0.46
0.50
0.93
1.20
0.99
Std
Dev
0.08
0.13
0.20
0.19
0.09
0.09
0.16
0.21
0.05
0.06
0.15
0.16
0.00
0.24
0.28
0.36
Exposure Results
Underexposed
Optimum exposure
Overexposed
Underexposed
Optimum exposure
Overexposed
Underexposed
Optimum exposure
Overexposed
Underexposed
Optimum exposure
Overexposed
*1 = Torso
2 = Extremity feather tracts
~*"Weighted averages
-------
It should be possible to get complete feather release with optimum exposure.
However, some of the experimental birds of relatively equal weight that were
subjected to the same treatment evidenced tissue damage, but comparable birds
did not. Presumably the tissue damage resulted from differences in tissue
water content. For example, birds with symptoms of breast blisters before
exposure showed tissue damage in that area after exposure.
The results of this experiment indicated the feasibility of using microwave
energy as a revolutionary approach to achieving feather release from chickens.
Commercial application of the process might be accomplished by either:
(a) weighing the birds before exposure and then subjecting different areas of
the body to microwaves in accordance with the relationship of the weight to
the proper time interval at a predetermined level of energy; or (b) predeter-
mining the microwave exposure time, then weighing each bird and determining
the energy level necessary for optimum exposure, thus allowing a processing
unit to proceed at normal line speed. Either approach would likely require
the use of a minicomputer on the line to make the determinations.
The potential energy saving from the microwave energy system over the tradi-
tional scalding system is substantial because microwave exposure would require
only an estimated 132 BTU's per bird, whereas heating the one quart of water
that is commonly used per bird would require about 200 BTU's. In addition,
the use of microwave energy would reduce problems associated with disposal of
the polluted water that results from the scalding process.
Our challenge is to develop equipment that will make the use of microwave
energy economically feasible in commercial processing operations.
REFERENCES
1. Gwin, J. N. The sub-scald method of dressing poultry. American Egg and
Poultry Review 11(11):8, 10 (1950).
2. Gwin, J. N. A report of progress on the scalding method of dressing
poultry. American Egg and Poultry Review 12(10):14, 73 (1951).
3. Gwin, J. N. The weight and quality of freshly dressed poultry as affect-
ed by dressing, cooling, and holding. American Egg and Poultry Review
12(2):38, 40 (1951).
4. Pool, M. F., Klose, A. A., and Mecchi, E. P. Observations on factors
influencing feather release. Poultry Sci. 40:1029-1036 (1961).
5. Klose, A. A. Poultry Scalding: Present Technology and Alternative
Methods. Proceedings & Abstracts, XV World's Poultry Congress p. 541-
542 (1974).
6. Miller, B. F. Unpublished data. Dept. of Animal Sciences, Colorado
State University, Fort Collins (1973).
177
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ACTIVATED SLUDGE TREATMENT OF WASTEWATERS
FROM THE DAIRY PRODUCTS INDUSTRY
by
P.H.M. Guo*, P.J. Fowlie*, and B.E. Jank*
INTRODUCTION
Regulations and guidelines for controlling the liquid waste from the Canadian
dairy industry are currently being developed by Fisheries and Environment
Canada. In conjunction with the task force activity to identify the best
practicable technology (BPT) for the treatment of dairy wastes, the Wastewater
Technology Centre, Burlington, Ontario undertook a comprehensive sampling and
monitoring program at three extended aeration activated sludge systems located
at dairy plants in Southern Ontario. These systems were selected because they
were considered to represent BPT or had the potential to be upgraded to re-
present BPT.
The program was carried out in June, July and part of August, 1977. These
months represent the annual peak production period of the Canadian dairy
industry.
Plant A produced ice cream, butter, powdered milk and ice products such as
popsicles and flavoured ice. The major products of plants B and C were butter
and powdered milk. Cheddar and Colby cheeses were also produced at plant B,
however, whey generated from a cheese making operation was separated and sold
as an animal feed supplement.
The specific objective of the program was to determine whether extended aerat-
ion activated sludge processes represented BPT for the treatment of dairy
wastes and to provide a data base to be used in the development of regulations
limiting the discharge of deleterious substances to the environment.
THE WASTEWATER TREATMENT SYSTEMS
Plant A
The wastewater from this plant was collected in four catch basins,each equip-
ped with bar screens with openings of 2 cm. The wastewater was pumped to a
30 m3 holding tank and flowed by gravity to a 675 m3 oxidation ditch as shown
in Figure 1. Aeration and mixing were provided by two cage rotors driven by
a 15 and a 19 kW motor, respectively. Mixed liquor flowed by gravity to a
* Wastewater Technology Centre, Fisheries and Environment Canada, Burlington,
Ontario, Canada
178
-------
PLANT A
RETURN SLUDGE
SLUDGE STORAGE
BASIN
OXIDATION DITCH
HOLDING TANK
SLUDGE
STORAGE
TANK
PILOT-SCALE
CLAHIFIER
SAMPLING
INFLUENT / FLOW
EQUALIZATION
TANK I pUMp
AERATION TANK
PILOT
SCALE
CLARIFIER
PLANT C
RETURN SLUDGE
CO
UJ
INFLUENT
-AERATOR
UJ
CO
EFFLUENT
HOLDING TANK
OXDATKDN DITCH
FIGURE 1. SCHEMATIC OF TREATMENT SYSTEMS
179
-------
^
4.9 m diameter peripheral feed clarifier, having a volume of 89 m . Neither
scum removing nor sludge scraping facilities were provided. The clarifier
effluent was pumped to the municipal sewer system.
Before the study was initiated, settled sludge was returned to the oxidation
ditch intermittently by a 1.8 m /min centrifugal pump which was set to operate
15 seconds every four minutes. Because of the hydraulic surges in the clari-
fier, this was changed to continuous operation at approximately 0.14 m3/min.
This mode of operation, providing a sludge recycle ratio of 1.2:1, was follow-
ed for the duration of the study.
Excess sludge was stored in a 675 m3 sludge storage basin (Figure 1) during
the winter months. During the summer operation, excess sludge was pumped from
the clarifier and sprayed on a field adjacent to the treatment system. As
sludge was not being stored in the basin at the time of the study, it was used
to equalize the flow to the treatment system.
Plant B
Wastewaters requiring treatment were collected in a catch basin equipped with
a 0.5 cm screen for separation of floating materials. The waste was pumped
to a 225 m3 flow equalization tank which was aerated by air diffusers. From
the equalization tank, the waste was pumped at a constant rate to the aeration
tank. The aeration tank having a capacity of 300 m3, was the outer compart-
ment of a 12.5 m diameter circular tank. The center compartment having a
capacity of 68 m3 was used as a clarifier. A schematic diagram of the treat-
ment plant is presented in Figure 1.
Aeration and mixing in the aeration cell were provided by diffused air which
was supplied by three 15 kW compressors located in a building adjacent to the
treatment system.
Mixed liquor flowed by gravity to the 4.6 m by 4.6 m clarifier which was
equipped with four sludge hoppers on the bottom. Settled sludge was recycled
to the aeration tank by four air-lift pumps, one in each sludge hopper. In
the original design, 100 mm diameter pipes were used in the air-lift pumps
providing a return sludge flow approximately 600% of the plant influent.
Shortly before the program was initiated, two of the pipes were reduced to
50 mm in diameter and the other two were replaced by 38 mm diameter pipes.
These modifications decreased the return sludge rate from 600 to 200% of the
plant influent.
The clarifier was equipped with a scum baffle at its perimeter to prevent
floating solids from discharging with the effluent. The floating solids
were collected in a pipe with a flared opening located at the center of the
clarifier. An air-lift pump delivered the floating solids thus collected to
the aeration tank. Effluent from the clarifier flowed by gravity to a creek.
Excess sludge was sprayed as necessary on a field adjacent to the treatment
system.
180
-------
Plant C
The design of the treatment system at plant C was similar to that of plant A.
The wastewater was pumped from a catch basin in the dairy plant to a 23 m3
holding tank and then flowed by gravity to the 495 m3 oxidation ditch as
shown in Figure 1. Aeration and mixing were provided by a cage rotor driven
by a 19 kW electric motor.
Mixed liquor flowed by gravity to a 4.3 m diameter peripheral feed clarifier
with the surface area and volume being 14.5 m and 58.5 m , respectively.
Neither scum removal nor sludge scraping equipment was provided in the clarif-
ier. Settled sludge was returned to the ditch by a 0.45 m3/min pump which
was operated by a timer to control the sludge recycle ratio at 40 to 250% of
the plant influent. The excess sludge was sprayed on the field adjacent to
the treatment system. The clarifier was housed in a building to prevent
freezing in winter. The effluent from this plant was discharged to a river.
Pilot-Scale Clarifier
It was originally identified that there were solid-liquid separation problems
with the clarifiers at plants A and B. Two pilot-scale clarifiers were in-
stalled and operated in parallel with the existing full-scale clarifiers.
The pilot-scale clarifiers had an 80 cm diameter and a settling volume of
0.6 m3. They were fed with the mixed liquor from the aeration basin at a
constant flow rate. Settled sludge from both pilot-scale clarifiers was pump-
ed to the aeration cells at 50-80% of the feed rate. Although sludge scraping
mechanisms were provided in both clarifiers, they were not equipped with scum
removal facilities.
MATERIALS AND METHODS
Monitoring Program
1. Collection four days per week of flow-proportioned, refrigerated, 24-hour
composite samples of plant influent and effluent. These were analyzed for
the biochemical oxygen demand (BOD5), suspended solids and pH;
2. Twice weekly collection of effluent samples for fish toxicity (Samples
were collected from the pilot-scale clarifiers at plants A and B and
from the full-scale clarifier at plant C);
3. Daily measurement of temperature, dissolved oxygen, suspended solids and
pH of the mixed liquor; and
4. Continuous measurement and recording of the flow rate to the treatment
system.
Bioassay Testing
Static with replacement bioassays were carried out in the study. The undilut-
ed effluent sample was cooled to 15°C and then sub-divided into four, 40-liter
samples each held in polyethylene containers lined with disposable food and
181
-------
drug approved polyethylene bags. Ten juvenile rainbow trout (Salmo
gairdneri) weighing between 1.5-2.0 g and averaging 4 to 5 cm in length were
placed in one of the 40-liter samples for the first 24 hours, then trans-
ferred to the second, third and fourth containers after 24, 48 and 72 hours,
respectively. Renewing the solutions every 24 hours provided an effluent
volume to fish weight ratio of 2 £/g-d. Dissolved oxygen concentrations in
the effluent were maintained above 7.0 mg/£ by aerating the test solutions at
5 mi/X-'min. Solutions not containing fish were not aerated until a few hours
prior to transferring the fish.
WASTEWATER FLOW AND CHARACTERISTICS
The flow rate and characteristics of wastes generated from each dairy plant
were different, depending on the quantity of milk and type of products being
processed. The degree of in-plant management exercised at each plant to
reduce the waste load accounted for the difference in the quantity and quality
of the waste. A discussion of the flow rate and characteristics of wastes
from each dairy plant is presented in the following sections.
Wastewater Flow
The flow rate to the treatment system at plant A ranged from 59 to 255 m3/d
(Figure 2). During the first week of the study, no effort was made to control
the flow to the treatment system and the daily flow rate fluctuated signifi-
cantly. In the second week, part of the waste was diverted to the spraying
field to reduce the hydraulic loading to the clarifier. Starting June 17, the
waste from the dairy plant was stored in the sludge storage basin and a sub-
mersible pump delivered the waste at a constant rate to the oxidation ditch.
Approximately one week later, odour problems were encountered in the basin.
Consequently, the daily flow rate to the treatment system was gradually
increased in an attempt to empty the basin. At the same time, efforts were
made to provide aeration and mixing to control the odour problems. During the
period from June 17 to July 8, although the total flow to the treatment system
changed from day to day, the flow rate was kept constant during individual
days. On July 8, the basin was completely emptied and thoroughly cleaned.
After July 8, the treatment system was operated at a flow 'rate which was
approximately equal to the total daily flow from the dairy plant. This mode
of operation allowed the sludge storage basin used for flow equalization to
be emptied daily and prevented the septic condition from occurring in the
basin.
Daily flow rate to the treatment system at plant B varied from 14 to 203 m3/d
with the average being 113 m3/d (Figure 2). Daily adjustment of the flow rate
was necessary in order to accommodate the flow variation coming from the dairy
plant, however, the flow rate to the treatment system was kept constant during
the individual days.
To promote mixing and oxygen transfer, the water depth in the flow equal-
ization tank was maintained at greater than 0.6 m at all times. On June 28,
the tank was emptied for cleaning. The discharge of the daily waste flow
182
-------
7 8 9 K> 14 15 16 17 21 22 23 24 28 28 30 5 6 7 8 12 13 14 15 19 20 21 22 26 27 28 29 3 4 5 9 K) 11 12
JUNE.1977 JULY.1977 AUGUST.1977
CC
PLANT B
7 8 9 10 14 IS 16 17 21 22 23 24 28 29 30 5 6 7 8 12 13 W 15 19 20 21 22 26 27 28 29 3 4 5 9 10 11 12
JUNE. 1977
JULY, 1977
AUGUST, 1977
FIGURE 2. DAILY WASTE FLOWS TO THE TREATMENT SYSTEMS AT
PLANTS A AND B
I "T T T T~T~ i—i—i—i T i—' T i—i—i—i—i—I—i—i T I—r
7 8 9 10 14 15 16 17 21 22 23 24 28 29 30 5 6 7 8 12 13 14 15 19 20 21 22 26 27 28 29
JUNE,1977 JULY, 1977
FIGURE 3. DAILY WASTE FLOWS TO THE TREATMENT SYSTEM AT PLANT C
183
-------
plus the content of the flow equalization tank resulted in a maximum daily
flow rate of 203 m3/d to the treatment system. The minimum flow rate occurred
on the following day, because part of the waste was stored in the flow equal-
ization tank to maintain the 0.6 m minimum liquid level necessary for aeration.
The daily average flow rate to the treatment system at plant C is shown in
Figure 3. The maximum and minimum flow rates for the individual days are also
presented. As can be seen from the figure, the flow rate fluctuated from day
to day as well as throughout the individual days. While the daily maximum
flow rate measured was 295 m /d the minimum flow rate was close to zero on a
number of occasions.
Wastewater Characteristics
BODs and Suspended Solids
The daily variation in the BODs and suspended solids concentrations for the
wastes from plants A, B and C is presented in Figure 4. Two abnormal peaks in
the concentration of both BODs and suspended solids were measured at plant A.
The first peak occurred during the period from June 9 to 14, when the holding
tank was being cleaned. The second peak occurred on July 8, corresponding to
the day the sludge storage pond was emptied and cleaned. On both occasions,
wastes with high milk solids were discharged to the treatment system, result-
ing in a great increase in the BODs an
-------
* PLANT A
'•• A. ^ A a
W -^v V-'
'X * / \
7 8 9 1)14151617212223242820305 6 7 81213141S19202122262728293 4 5 9 » 11 12
JUNE.1977 JULX1977 AUGUST.1977
7 8 010M1Siei7212223242a2S305 6 7 8 1213U151&2021222728293 4 5 9 10 11 12
JUNE.1977 JUX1977 AUC3UST.1977
PLANT C
7 8 9 10 14 15 16 17 21 22 23 24 28 29 30 5 6 7 8 12 13 14 15 19 20 21 22 26 27 28 29
JUNE, 1977 JULY, 1977
FIGURE 4. DALY INFLUENT BOD5 AND SUSPENDED SOLIDS
CONCENTRATIONS
185
-------
TABLE 1. SUMMARY OF INFLUENT WASTEWATER CHARACTERISTICS
Parameters Minimum Maximum
A B C ABC
Average
ABC
BOD5
(mg/£) 1700 840 380 6000 3800 1900 2850 1960
950
Suspended
Solids (mg/a) 350 300 610 5190 2460 2500 1290 1120 1240
PH
3.8 4.4 7.2 10.1 10.9 12.0
The pH of the untreated waste was also highly variable for all the plants.
The major factor affecting the pH was the type and quantity of sanitizers and
cleaning agents used in the dairy plant. As shown in Table 1, the pH of the
wastes from plants A and B had a greater degree of variation than that from
plant C. At plant C, the waste had a significantly higher pH value than that
from the other two plants, indicating the difference in the use of sanitizers
and cleaning agents at this plant.
OPERATING PARAMETERS OF TREATMENT SYSTEMS
The average operating parameters for the three treatment systems are shown in
Table 2. Based on the organic loadings, it could be seen that all three
systems were operated as an extended aeration activated sludge process. The
day to day fluctuation in the mixed liquor suspended solids for the three
treatment systems is presented in Figure 5. A significant increase in MLSS
concentration occurred in the oxidation ditch at plant A on July 8, when the
storage basin was emptied. This was caused by the discharge of a high con-
centration of milk solids into the treatment system. Although efforts were
made to control the solids concentration by sludge wasting on the following
days, it was impossible to reduce the concentration to its original level due
to the limited capacity of the sludge wasting facilities. A steady decrease
in the MLSS concentration did not occur until July 22; two weeks after the
increase in the solids concentration. Apparently, the amount of sludge wasted
during this period was offset by the rapid solids build-up due to microbial
growth and the high influent suspended solids concentration.
The dissolved oxygen level in the oxidation ditch at plant A was generally
maintained above 2 mg/Ji. The discharge of the high concentration of milk
solids resulted in a drop of dissolved oxygen concentration to less than 0.5
mg/£ during the period from July 8 to 13. Low dissolved oxygen levels
measured on July 5 and 29 were caused by a malfunction of one surface aerator.
186
-------
00
CO
O
8000-
6000-
4000 H
2000-
jfj 6000H
O
O 5000-
o
VI 4000-
6000-
5000-
4000-
3000-
2000-1—r
7
PLANT A
V
V
V
PLANT B
O-o-O
PLANT C
/ \
y
**•—+'
-|—i—r—i—i—i—i—i—i—i—i—i—r
10 14 15 16 17 21 22 23 24 28 29 30 5
~i—i—i—i—i—i—i—i—i—i—i—^—>—r
8 12 13 14 15 19 2021 22 2627 28 29 3
~I—I 1—T
5 9 10 11 12
JUNE,1977
JULY, 1977
AUGUST, 197 7
FIGURE 5. MIXED LIQUOR SUSPENDED SOLIDS CONCENTRATIONS
-------
The MLSS concentration in the aeration tank at plant B was maintained between
3900 and 6600 mg/£ (Figure 5). Although the three compressors were operated
at full capacity, 50% of the time, the dissolved oxygen level in the aeration
tank was less than 1 mg/£ and 75% of the time, it was lower than 2 mg/£. Dis-
solved oxygen concentrations less than 0.5 mg/£ were measured on several
occasions and these were related to compressor breakdowns. There was no spare
unit available to provide reserve aeration capacity for emergencies.
TABLE 2. AVERAGE OPERATING PARAMETERS
1. Aeration Tank
Flow Rate (m3/d)
Plant A
142
Plant B
113
Plant C
170
Organic Loading
(kg BOD5/kg MLSS-d)
Detention Time (d)
MLSS Concentration (mg/£)
2. Clarifier
Surface Loading (m3/m2-d)
Solids Loading (kg/m *d)
(1) Full-Scale Clarifier
(2) Pilot-Scale Clarifier
0.11
4.8
5300
111 .(.?_)..
10 14
44 49
0.14
2.7
5070
(1) (2)
5 14
24 65
0.08
2.9
4030
16
54
At plant C, the MLSS concentration was generally maintained between 3500 and
4500 mg/£ (Figure 5). There was sufficient dissolved oxygen in the oxidation
ditch except for two occasions when extremely low concentrations (less than
0.5 mg/£) were measured. The cause of the low dissolved oxygen reading was
not identified.
Although the influent pH was highly variable as mentioned previously, little
change was observed in the pH of the mixed liquor in the aeration tanks of all
three treatment systems. It ranged from 6.9 to 7.9 for the mixed liquor of
the treatment systems at plants A and B and from 7.4 to 8.8 for plant C. The
slightly higher pH value of the mixed liquor at plant C could be related to
the higher influent pH. As all the mixed liquor pH's were within the optimum
range for microbial growth in a biological treatment system, there was no
requirement for chemical addition for pH adjustment. It must be concluded
that there was always sufficient mixing and buffering capacity in the aeration
188
-------
tank to neutralize the waste.
The surface and solids loadings of the full- and pilot-scale clarifiers are
shown in Table 2. The loadings shown for the pilot-scale clarifiers were
calculated based on a flow rate of 4.6 £/min.
OPERATING RESULTS
Plant A
The daily effluent BODs and suspended solids concentrations for both the
pilot- and full-scale clarifiers are shown in Figure 6 and 7, respectively.
As can be seen from the figures, the pilot-scale clarifier operated at a
constant flow rate produced significantly better quality effluent during the
first month of operation. After the operational problems in the full-scale
clarifier were rectified by flow equalization, a stable operation was achieved.
Starting July 6, the quality of effluents from both clarifiers was compar-
able.
The deterioration in the effluent quality of the pilot-scale clarifier on
July 13 and 14, could be related to the high solids concentration in the
oxidation ditch caused by the discharge of milk solids. The significant
increase in the MLSS concentration after July 8, resulted in an increase in
solids loading from 49 to 88 kg/in2- d which was too high for the pilot-scale
clarifier. The sludge blanket was at the top of the clarifier on both days.
To rectify the problem, the feed rate was reduced from 4.6 to 3.2 il/min on
July 15 which resulted in a reduction of the solids loading from 88 to 63
kg/m2-d and the surface loading from 14 to 10 m3/m2-d. As a result, the
sludge blanket dropped and good quality effluents were achieved for the rest
of the study.
The average BODs and suspended solids concentrations for effluents from the
pilot-scale clarifier were 12 and 43 mg/£, respectively, which corresponded
to a 99% BODs and 97% suspended solids reduction. These results were cal-
culated using all the collected data except those on July 13 and 14.
Effluent data from the full-scale clarifier could be divided into two groups.
One group dealt with the data collected prior to July 5, which covered the
first five weeks of operation. BOD5 and suspended solids concentrations
during this period of operation were extremely high and exhibited a great
degree of fluctuation. The other group represented the data obtained after
July 6, when the daily waste flow to the treatment system was kept constant.
This group of data collected over a period of approximately six weeks re-
presented the performance of a well designed and properly operated treatment
system and was considered to be representative of the BPT operation. A
summary of the operating results for this group is shown in Table 3.
189
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CHANGE TO CONSTANT FLOW
*— FULL-SCALE CLARFIER
.— PILOT-SCALE CLARIFIER
n—i—i—r—i—r—i—i—i—i—f—f—i—i—i—i—i—i—i—i—i—i—i—i—r—i—i—i—i r
7 8 9 10 14 15 16 17 21 22 23 24 28 29 30 5 6 7 8 12 13 14 15 18 20 21 22 26 27 28 29 3 4 5 9 10 11 12
JUNE, 1977
JUNE, 1977
AUGUST, 1977
FIGURE 6. DAILY EFFLUENT BOD5 CONCENTRATIONS AT PLANT A
CHANGE TO CONSTANT FLOW
FULL-SCALE CLARIFIER
PILOT-SCALE CLARFIER
i—i—l—l—l—l—i—i—i—i—'—i—i—i—i—r—i—i—i—i—i—i—i—r—r
7 8 B 10 14 16 16 17 21 22 23 24 28 28 30 5 6 7 8 12 '3 14 15 19 20 21 22 26 27 26 29 3 4 5 9 10 11 12
JUNE, 1977 JULY, 1977 AUGUST, 1977
FIGURE 7. DAILY EFFLUENT SUSPENDED SOLIDS CONCENTRATIONS AT PLANT A
190
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TABLE 3. SUMMARY OF EFFLUENT RESULTS - PLANT A,
FULL-SCALE CLARIFIER*
Parameters
BOD5 (mgA)
Suspended Solids (mg/£)
Minimum
7
12
Maximum
29
109
Average
13
32
% Reduction
99
98
* Data collected from July 6 to August 12, 1977
From the data presented, it can be seen that the performance of the treatment
system was significantly improved by flow equalization. Before June 17, the
sludge blanket in the clarifier was visible at all times and on several
occasions it reached the water surface resulting in severe loss of sludge over
the weir of the clarifier. Starting June 17, when the sludge storage basin
was used to equalize the flow, the sludge blanket gradually dropped in the
clarifier. Approximately one week later, the sludge blanket was no longer
visible.
During the operating period from June 24 to July 7, scum was observed in both
clarifiers. The scum was formed in the oxidation ditch and was carried over
to the clarifier with the mixed liquor. As neither the full-scale nor the
pilot-scale clarifier was equipped with scum removal facilities, the solids
were carried away with the effluent resulting in a high suspended solids con-
centration in effluents from both clarifiers (Figure 7). However, the BODs
results were only slightly affected by the scum in the sample as shown in
Figure 6. This indicated that most solids in the scum were inert and did not
exert an oxygen demand.
A malfunction of the effluent pump caused by power failure on June 30, resulted
in a rise of the water level and sludge blanket in the full-scale clarifier.
The high sludge blanket, in addition to the scum problem mentioned earlier,
could have been partially responsible for the high effluent BODs and suspended
solids concentrations measured.
After July 6, stable operation of the treatment system was achieved. The dis-
charge of 210 m3 of highly concentrated wastes to the oxidation ditch on July
8, appeared to have no affect on the performance of the treatment system.
As indicated before, aqueous ammonia was added to the waste as a supplemental
nitrogen source. During the first two weeks of operation, ammonia was added
at 200 mg/ji in terms of nitrogen. This dosage was based on an estimated
influent EOD^ concentration of 4000 mg/£. As excessive ammonia concentrations
in the effluent samples were detected, the dosage was reduced to 114 mg/£ on
June 16. Although the effluent ammonia concentration started to decrease, a
steady increase in the nitrite concentration was observed in effluents from
191
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both clarifiers. Apparently the ammonia dosage was still too high and the
decrease in the effluent ammonia concentration after the reduced dosage was
partially attributed to nitrification occurring in the system. On July 4,
the ammonia dosage was reduced again to 58 mg/£. Two days later, a steady
decrease in the nitrite concentration was measured in the effluent. After
July 13, both the ammonia and nitrite concentrations in the effluent were
consistently less than 1 mg/£ expressed as nitrogen.
During the period when high nitrite concentrations were measured in the
effluent, no nitrate was detectable, indicating that nitrification was not
complete. The cause of this phenomenon was not investigated during the study.
Plant B
The daily BODs concentration of effluents from both the full- and pilot-scale
clarifiers is shown in Figure 8. The effluent suspended solids data are
presented in Figure 9. As can be seen from Figure 8, the. BODs results from
both clarifiers were comparable. The discharge of a highly concentrated
waste, combined with the extremely high flow rate on June 28, detrimentally
affected the performance of the treatment system. A substantial increase in
the population of filamentous micro-organisms was observed in the sludge
floe and the sludge blanket in both clarifiers reached the water surface
during the period from June 28 to July 6. The continuous loss of sludge over
the clarifiers resulted in a deterioration of the effluent quality as shown
in Figures 8 and 9.
Scum, similar to that occurring in the treatment system at plant A, was
frequently observed in both clarifiers. As the full-scale clarifier was
equipped with baffle and skimming devices, the scum, if not too excessive,
could be prevented from discharging with the effluent. However, such facili-
ties were not available in the pilot-scale clarifier. As a result, effluents
from the; pilot-scale clarifier usually contained higher suspended solids than
those from the full-scale clarifier.
Aside from the period between June 28 and July 6, suspended solids concent-
rations greater than 100 mg/£ were measured in the effluent from the full-
scale clarifier on four occasions. This was attributed to an excessive scum
accumulation in the clarifier, resulting in partial discharge of solids with
the effluent.
Rising bubbles and lumps of black sludge were observed in the full-scale
clarifier on several occasions. As the clarifier was not equipped with
sludge scraping mechanisms, this allowed part of the sludge to adhere to the
bottom of the clarifier. Prolonged storage of sludge resulted in denitrifi-
cation or the development of septic conditions which caused the sludge to
rise to the surface. Because the clarifier was equipped with scum baffle,
the floating sludge was retained in the clarifier and prevented from leaving
with the effluent. Eventually the floating sludge either sank to the bottom
or was collected by the skimming device and returned to the aeration tank by
an air-lift pump. This problem was not encountered in the pilot-scale
clarifier as it was equipped with sludge scraping facilities.
192
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600-
500-
400-
300-
O 200-
100-
—o— FULL-SCALE CLARIFIER
PILOT-SCALE CLARIFIER
-I—i—i—i—r
7 8 9 10 14 15 16 17 21 22 23 24 28 29 30 5 6 7 8 12 13 14 15 19 20 21 22 27 28 29 3 4 5 9 10 11 12
JUNE.1977 JULY, 1977 AUGUST, 1977
FIGURE 8. DAILY EFFLUENT BOD5 CONCENTRATIONS AT PLANT B
O)
O
3000-
2000-
1000-
' >
400-
300-
200-
100-
*5800
o—FULL-SCALE CLARIFIER
•--PILOT-SCALE CLARIFIER
7 8 9 10 14 15 16 17 21 22 23 24 28 29 30 5 6 7 8 12 13 14 15 19 20 21 22 26 27 28 29 3 4 5 9 10 11 12
JUNE ,1977 JULY, 1977 AUGUST, 1977
FIGURE 9. DAILY EFFLUENT SUSPENDED SOLIDS CONCENTRATIONS
AT PLANT B
193
-------
A summary of the operating results is presented in Table 4. These results
were calculated using the data considered to be representative of the BPT
operation. The data collected from June 28 to July 6, when the system was
upset due to the discharge of a concentrated septic waste, were not included.
The percent reduction was calculated using the average values shown in
Tables 1 and 4.
As indicated in the table, the quality of effluents from the full-scale
clarifier was slightly better than that from the pilot-scale clarifier. The
average effluent BODs concentration for the full-and pilot-scale clarifiers
was 22 and 25 mg/£, respectively, which corresponded to a 99% reduction for
both clarifiers. The effluent suspended solids concentration averaged 55
and 65 mg/& for the full- and pilot-scale clarifiers, respectively, which re-
sulted in a 95 and 94% reduction as shown in the table.
TABLE 4. SUMMARY OF EFFLUENT RESULTS* - PLANT B
Parameters
Minimum
(1) (2)
Maximum
(1) (2)
Average
(1) (2)
% Reduction
(1) (2)
BOD5 (mg/£) 37 50 63 22 25 99 99
Suspended
Solids (ing/A) 9 24 250 368 55 65 95 94
* Excluding the data collected from June 28 to July 6.
(1) From the full-scale clarifier
(2) From the pilot-scale clarifier
Plant C
The plot of effluent BODs and suspended solids concentrations versus date of
operation is shown in Figure 10. As indicated in the figure, the majority of
effluent BODs and suspended solids concentrations were less than 20 and 50
mg/£,, respectively. Occasionally, temporary problems with hydraulic surges
were encountered in the clarifier. On June 14, 24, 29 and 30, and July 5 and
7, the sludge blanket reached the water surface for periods ranging from 2 to
12 hours, causing loss of solids in the clarifier. The resultant high BODs
and suspended solids concentrations are encircled and shown as unconnected
points in Figure 10. On these days, in addition to the usual 24-hour compos-
ite sample, another composite sample was prepared using samples taken during
the hours of normal operation. Analytical results for these samples are
presented as connected points in the same figure. The number of hours of
normal operation varied from 12 to 22 hours and has been noted in the figure.
194
-------
Ol
1000 H
O)
<
DC
LLJ
O
§
O
500-
100
TT
1598 1793
—•— ss
® )
® }
CAUSED BY
® HYDRAULIC SURGES
"I—I—I—I—I
8 9 10 14 15 16 17 21 22 23 24 28 29 30 5
JUNE, 1977
~i—i—i—i—i—i—r~i—i—i—i—i—i—r
7 8 12 13 14 15 19 20 21 22 26 27 28 29
JULY, 1977
FIGURE 10. DAILY EFFLUENT BOD5 AND SUSPENDED SOLIDS CONCENTRATIONS AT
PLANT C
-------
During the week of July 19 to 22, floating sludge was observed in the clarif-
ier. The problem could be attributed to nitrification or the development
of septic conditions in the clarifier as mentioned previously. The discharge
of floating solids with the effluent resulted in a deterioration of the
effluent quality as shown in Figure 10.
Since the problems with the hydraulic surges were of a temporary nature, and
could have been readily rectified by adequate flow equalization, the encircled
values were considered to be not representative of BPT operation, and there-
fore, were not included in the data anlysis.
A summary of the operating results for the treatment system is presented in
Table 5. The average effluent BODs and suspended solids concentrations were
7 and 28 mg/£, respectively, which corresponded to a 99% BODs and 98% sus-
pended solids removal.
The results from the summer operating period were compared with those from a
similar sampling program carried out at this plant in February and March
1976. During the winter program the system was operated at an average
organic loading of 0.09 kg BODs/kg MLSS-d at a liquid temperature of approxi-
mately 8°C. The results from the 5-week sampling program indicated that the
average effluent BOD5 and suspended solids concentrations were 7 and 12 mg/£,
respectively; these values represent a 99% removal for both BODs and suspend-
ed solids. These results show that at a similar organic loading, performance
of the treatment system was not affected by a significantly reduced liquid
temperature.
TABLE 5. SUMMARY OF EFFLUENT RESULTS* - PLANT C
Parameters Minimum Maximum Average % Reduction
BOD5 (mg/X,) 2 18 7 99
Suspended Solids (mg/£) 5 49 28 98
*Excluding the data collected when the clarifier was affected by hydraulic
surges
BIOASSAY RESULTS
The results of fish bioassays are shown in Table 6. As indicated, the major-
ity of the samples were non-acutely lethal to rainbow trout. The four samples
which exhibited 100% mortality, were associated with high ammonia concent-
rations in the effluent. Ammonia has been reported to be lethal to rainbow
trout in the un-ionized form (NH3) at 0.2 to 0.5 mg/£ in terms of nitrogen (1).
Analytical results indicated that the samples exhibiting 100% fish mortality
contained 0.7 to 2.9 mg/£ of non-ionized ammonia expressed as nitrogen. The
196
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high ammonia concentration present in the effluent from the treatment system
at plant A was due to an over-dosage of ammonia in the waste as indicated
previously. No explanation could be provided for the high ammonia concent-
ration in the effluents from the treatment systems at plants B and C.
TABLE 6. BIOASSAY RESULTS
Plant
No. of
Samples
Tested
No. of Samples
Exhibiting No
Mortality
Remarks
A 15 11 1 sample exhibited 100% mortality
1 sample exhibited 20% mortality
2 samples exhibited 10% mortality
B 17 15 Both samples exhibited 100% mortality
C 15 14 100% mortality
As mentioned previously, over-dosage of ammonia during the early weeks of the
study also resulted in a high nitrite concentration in the effluent. Analy-
tical results indicated that the three samples from plant A exhibiting partial
mortality contained 36 to 96 mg/£ of nitrite-nitrogen which were 150 to 400
times the lethal level of 0.23 mg/£ reported by Brown and McLeay (2). How-
ever, only 10 to 20% mortality was observed, suggesting that some form of
antagonism was occurring in the sample. Perrone and Meade (3) reported a
positive interaction between nitrite and chloride. Subsequent analyses of the
effluents revealed chloride levels of 200 to 500 mg/£. The antagonistic
relationship was confirmed by exposing rainbow trout to 50 mg/£ of nitrite-
nitrogen with and without 300 mg/£ of chloride. The samples containing
chloride were non-acutely lethal while samples without chloride resulted in
100% mortality.
OPERATIONAL PROBLEMS AND CORRECTIVE MEASURES
Three major operational problems were encountered at the treatment systems
during the study. The nature of the problems and their corrective measures
are presented as follows:
Hydraulic Surges
Hydraulic surges to the treatment system caused by washing and cleaning ope-
rations in the dairy plant have resulted in overloading of the clarifiers at
plants A and C. The hydraulic surges lifted the sludge blanket to the surface
of the clarifier, resulting in a discharge of suspended solids. The solution
to the problem was to provide a constant flow to the treatment system which
can be accomplished by the use of a flow equalization tank. This can be
197
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provided through the construction of new facilities or through the modifi-
cation of existing facilities. During the study the sludge storage basin at
plant A was used for this purpose. However, it should be noted that the
basin is not available for flow equalization in winter months as it is used
to store the excess sludge from the treatment system. To ensure a satis-
factory performance year-round, flow equalization is required.
At plant C, an attempt was made to determine the feasibility of using the
existing holding tank to equalize the flow. The diurnal flow pattern of the
day having the most variable flow during the study was selected (Figure 11)
and a hydrograph was constructed as shown in Figure 12. The vertical distance
between the two solid lines tangent to the accumulated flow curve represents
the storage volume required. This volume was calculated to be 23 m3 which
happened to be the same as the volume of the holding tank on site. Therefore,
it is feasible to operate the holding tank as a flow equalization tank to pro-
vide a constant flow to the oxidation ditch. The only modification required
is to install a pump having the capacity to handle the average daily flow.
As no reserve capacity is available, occasional overflow could occur due to
unforseen changes in diurnal flow. The effect of such an overflow on the
treatment system would be less significant than the effect of the unequalized
hydraulic surges experienced during the study.
The problems with hydraulic surges did not occur at plant B, because a flow
equalization tank was available at this plant.
Scum
During the study, the aeration tanks at plants A and B were covered with a
thick scum sometimes to a depth of 0.5 m. It was called 'scum' rather than
'foam' because it could not be collapsed by water spraying. Part of the scum
entered the clarifiers with the mixed liquor, resulting in floating solids in
the clarifiers. As no scum removal facilities were available at plant A, the
solids were carried over the weir of the clarifier, producing effluents with
high suspended solids concentration. The scum in the clarifier at plant B
was retained by the scum baffle and eventually was returned to the aeration
tank by an air-lift pump or removed manually.
The solution to the problem is to control the scum formation, or failing this,
to remove the scum from the oxidation ditch. Scum can be prevented from
entering the clarifier with the mixed liquor by a properly designed entrance
facility. As a final measure, scum baffle and skimming devices should be pro-
vided in the clarifier to keep the scum from discharging with the effluent.
Floating Sludge
Rising bubbles and lumps of black sludge were observed on several occasions,
in each of the full-scale clarifiers. As none of the clarifiers were equip-
ped with sludge scraping mechanisms, this allowed part of the sludge to
adhere to the bottom of the clarifier. Prolonged storage of sludge resulted
in denitrification or the development of septic conditions which caused the
sludge to rise to the surface.
198
-------
250-
^ 200-
CO
PO^
LU
OC 100-
^ 50-
SAM 12
NOON
4PM 8PM 12 4AM SAM
MID - NIGHT
TIME
FIGURE 11. THE MOST VARIABLE DIURNAL FLOW PATTERN AT PLANT C
150-
00
LU
100-
LU
o
50-
TANK IS FULL
STORAGE
CAPACITY
REQUIRED I
SAM 12
NOON
4PM 8PM 12 4AM SAM
MID-NIGHT
TIME
FIGURE 12. HYDROGRAPH FOR THE DIURNAL FLOW PATTERN
PRESENTED IN FIGURE 11
199
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The solution to the problem is self-evident. The provision of a sludge
scraper to facilitate a rapid movement of the settled sludge to the hopper
for recycling or wasting is essential in the design of the clarifier. The
importance of the scum removal facility should not be overlooked as it pro-
vides a final protection to prevent the floating solids including scum and
floating sludge from discharging with the effluent.
CONCLUSIONS
Based on the results from the study, the following conclusions can be drawn:
1. The extended aeration activated sludge process can be considered to
represent best practicable technology for the treatment of dairy wastes.
2. The three extended aeration activated sludge systems were operated at
organic loadings of 0.11, 0.14 and 0.08 kg BODs/kg MLSS-d, respectively.
In each case, 99% BODs reduction was attained. For suspended solids a
98% reduction was achieved at the treatment systems of plants A and C,
and 95% at plant B. The average effluent concentrations for the three
treatment systems were 13, 22 and 7 mg/£ for BODs and 32, 55 and 28 mg/£
for suspended solids.
3. Hydraulic surges due to washing and cleaning operations of the dairy
plant detrimentally affected the performance of the treatment systems
at plants A and C. This problem was not encountered at plant B, because
flow equalization facilities were available. The use of the existing
sludge storage basin for flow equalization at plant A substantially
improved the performance of the treatment system.
4. Occasionally, floating sludge due to denitrification or the development
of septic conditions in the clarifier was observed in the full-scale
clarifiers. Scum formed in the aeration cells at plants A and B was
carried over to the clarifiers with the mixed liquor. The provision of
scum baffle and skimming devices in the clarifier at plant B prevented
the floating sludge from discharging with the effluent. The absence of
such facilities in the other clarifiers resulted in a deterioration of
the effluent quality.
5. The majority of the effluents from the three treatment systems were non-
acutely lethal to rainbow trout. In cases where fish mortality was
observed, it was identified to be related to high un-ionized ammonia
concentrations in the effluent. Effluents containing high nitrite con-
centrations were not acutely lethal, presumably due to the antagonistic
interaction between nitrite and chloride present in the effluents.
DESIGN RECOMMENDATIONS
The results of the study indicated that dairy wastes can be treated success-
fully in a properly designed and well operated extended aeration activated
sludge system. To ensure a satisfactory operation at all times, the system
should consist of the following components:
200
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1. Catch basin equipped with screening devices to remove large floating
materials.
2. Flow equalization tank to provide a constant flow to the subsequent
treatment units.
3. Aeration tank to oxidize the organic compounds in the waste.
4. Clarifier to separate the biological solids from the liquid.
A supplemental nitrogen source will be required for treating the wastes which
are deficient in this nutrient.
Based on the experience gained at the three systems, the following important
parameters should be considered in the design of a treatment system.
For the flow equalization tank, the volume is determined, based on the diurnal
flow pattern of the waste to be treated. Aeration and mixing should be pro-
vided to prevent septic conditions and to avoid deposition of solids in the
tank.. Design details on this subject are covered in an EPA report entitled
"Flow Equalization" (4).
As an alternative, the use of the aeration tank to dampen the flow and a pump
to provide a constant flow of mixed liquor to the clarifier may be a cost-
effective solution for some treatment systems. However, the feasibility of
using this mode of operation is dependent on the degree of flow variation and
should be investigated on a case by case basis.
The aeration tank should be designed at an organic loading of approximately
0.1 kg BODs/kg MLSS'd. Sufficient aeration and mixing should be provided to
maintain a dissolved oxygen level at greater than 1 mg/H, preferably 2 mg/£
throughout the aeration tank. Efforts should be made to keep the MLSS con-
centration between 4000 and 6000 mg/£.
The use of a completely mixed aeration cell is strongly recommended as it
minimizes the effect of fluctuating pH levels in the dairy wastes and provides
a well balanced system without additional pH adjustment. The requirement for
a pH control facility is thus eliminated.
As the sludge floe produced from the system treating dairy wastes always con-
tains filaments and is non-compact in nature, a conservative surface loading
of less than 16 m3/m2'd is recommended in the design of the clarifier. This
was selected based on the loading used at plant C, which was the highest
among the three treatment systems investigated. Higher loadings may be used
if justified by experimental data on sludge settling characteristics. Sludge
scraping mechanisms must be provided in the clarifier to facilitate a rapid
movement of the settled sludge to the hopper for recycling or wasting. As
indicated before, prolonged storage of settled sludge in the clarifier result-
ed in a significant deterioration of the effluent quality. It is, therefore,
essential to operate the clarifier with as little sludge on the bottom as
possible. The sludge recycling and wasting equipment should be provided with
sufficient capacity to ensure prompt removal of settled sludge.
201
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As scum is frequently formed in the aeration cell .arid carried over to the
clarifier with the mixed liquor, the clarifier should also be equipped with
baffle and skimming devices to prevent the scum and other floating solids
such as rising sludge from discharging with the effluent.
Based on the performance data obtained from the three treatment systems invest-
igated, a properly operated extended aeration activated sludge system,
designed according to the above criteria should produce effluents containing
less than 20 mg/£ of BOD5 and 30 mg/X, of suspended solids.
ACKNOWLEDGEMENTS
The authors wish to acknowledge the support of the management and staff of the
three dairy plants .involved in the study. Special appreciation is expressed
to Messrs. K. Conn and V.W. Cairns, Laboratory Services Section of the Waste-
water Technology Centre (WTC) for carrying out chemical analyses and fish
bioassays. The authors also wish to thank Mr. Ron Gillespie of the Facilities
Services Section,WTC, for setting up the pilot-scale clarifiers and associated
equipment for the study.
REFERENCES
1. EIFAC Water Quality Criteria for European Freshwater Fish, "Report on
Ammonia and Inland Fisheries", Food and Agriculture Organization of the
United Nations, Rome, Technical Report No. 11, 1970.
2. Brown, D.A. and McLeay, D.M., "Effects of Nitrite on Methemoglobin and
Total Hemoglobin of Juvenile Rainbow Trout", The Progressive Fish -
Culturist, 37(1):36-38, 1975.
3. Perrone, S.J. and Meade, T.L., "Positive Effect of Chloride on Nitrite
Toxicity to Coho Salmon (Oncorhynchus kisutch)", Journal of the Fisheries
Research Board, 34:486-492, 1977.
4. Environmental Protection Agency, Flow Equalization" EPA Technology Trans-
fer Seminar Publication, 1974.
202
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TREATMENT OF BIRD CHILLER WATER FOR
REUSE IN FLUMING BROILER GIBLETS
by
H. S. Lillard *
INTRODUCTION
There are over 400 federally inspected broiler processing plants in the
United States. A typical plant processes about 9000 birds per hour or about
70,000 per day. Modern processing methods make liberal use of water which,
by federal inspection regulations, has to be of potable quality (1). Water
shortages in certain areas and the rising cost of potable water and effluent
discharge are cause for concern. Total water usage in the average plant is
about 1 million gallons per day. One of the largest plants in Georgia,
processes 200,000 birds per day, and reports using 30 million gallons of
water per month at a cost of about $27,000 for potable water and effluent
discharge.
Carawan ^t al., in an EPA sponsored study, showed that the gizzard machine
and giblet flumes required the most water and accounted for about 30% of the
potable water used in the plant surveyed (2). Therefore, I studied the
giblet operation in the first phase of a program which has two main
objectives: (1) To examine the requirement for potable water in all phases
of processing except scalding; (2) To determine the feasibility of conserving
water in poultry processing plants by reusing water from a relatively clean
process in another process. This report is a review of my work to date in
the area of water reuse. Further details on methodology and results are
available in the original references cited.
FEASIBILITY STUDY OF WATER REUSE
The initial step of studying the feasibility of reusing processing water was
to compare the microbial populations of both water and product from various
processing points in a commercial plant where potable water is used and,
therefore, represents the best available technology. Table 1 shows that the
level of fecal coliforms in water from the giblet flume was significantly
higher than that in water from the giblet chiller but that the levels in the
products from both sources were not significantly different. These results
led to the conclusion that quality of processing water is not necessarily
* USDA, SEA, Richard B. Russell Agricultural Research Center, P. 0. Box 5677,
Athens, GA. 30604
Mention of firm names does not imply endorsement of the products by the
U. S. Department of Agriculture. No discrimination or preference is
intended. The use of firm names and products is for identification only.
203
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directly related to quality of product and, although processing water washes
off loosely attached microorganisms, bacteria that are attached to the skin
of broilers probably remain attached and cannot be washed off (3).
TABLE 1. MICROBIOLOGICAL QUALITY OF WATER AND
PRODUCT FROM GIBLET FLUMES AND CHILLERS
WATER (52 samples) 1
Sample Fecal
Source (mean
Giblet flume
Gib let chiller
coliforms
Iog10/ml)
3.00
2.10
Salmonellae
No.+/total
15/52 a
18/52 a
PRODUCT (78 samples)
Fecal coliforms
(mean log1Q/ml)
2.32 b
2.30 b
Salmonellae
No.+/total
4/78 c
4/78 c
The same lower case letter follows values which are not significantly
different at the 5% level.
Results of a microbiological evaluation of water from another processing
plant are shown in Table 2.
TABLE 2. MICROBIOLOGICAL QUALITY OF PROCESSING WATER
Mean log-0/ml
(Based on 26 samples)
Water
Source
Neck flume
Neck chiller
Bird chiller
Aerobic,
counts
3.81 a
3.87 a
3.49 a
Fecal -
coliforms
3.11 b
3.44 b
2.48 b
The same lower case letter follows values which are not significantly
different at the 5% level.
204
-------
These data show that aerobic counts and fecal coliform levels did not differ
significantly in processing water from the neck flume, neck chiller and the
bird chiller (4).
These two surveys showed that for water and energy conservation, water from
the bird chiller might be used to flume and cool giblets without adversely
affecting product quality.
FLUMING NECKS WITH UNTREATED BIRD CHILLER WATER
Necks were used in the next phase of this study because they represented the
least cost to the processor. A 1/4 scale simulated giblet flume was
constructed in cooperation with a commercial processor (Fig. 1). In an area
away from the main processing plant, necks were flumed with potable water or
with bird chiller water pumped from the overflow. Holding time of necks and
ratio of necks to water in the simulated flume were the same as for the
commercial flume in this plant. Necks flumed with bird chiller water were
compared with those flumed with potable water in the simulated flume.
Salmonellae incidence and levels, fecal coliform levels and shelf-life were
the same for necks flumed with untreated bird chiller water and those flumed
with potable water. However, aerobic counts were 1/4 log higher for necks
flumed with bird chiller water than for necks flumed with potable water (5).
To eliminate this difference in counts treatment of the chiller water was
necessary. Regulatory approval for reuse of chiller water without further
improvement would be denied on the basis of esthetic considerations.
Therefore, chlorination of bird chiller water without further improvement
was not considered the best approach. Rogers (6), in an EPA sponsored study,
screened various methods for removing organic matter from chiller water. The
method he found the most promising was to filter the chiller water through
diatomaceous earth in a pressure leaf filter. Therefore, I next undertook to
evaluate the microbiological, chemical and physical properties of bird
chiller water filtered through diatomaceous earth (DE) (7), and to evaluate
the effect on necks of fluming with DE-filtered chiller water with and
without chlorination (8).
TREATMENT OF CHILLER WATER
Figure 2 is a schematic diagram of a DE pressure leaf filter and the line of
flow. A 1:1 w/w mixture of two grades of DE (Speedflow plus Dicalite 4200)
was used to coat the 6 leaves prior to filtering the chiller water.
Filtration of bird chiller water through diatomaceous earth significantly
lowered solids and grease contents (Table 3).
Filtration also improved the microbiological quality of chiller water.
Reductions in aerobic counts and fecal coliforms were significant at the
1% level (Table 4).
205
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NJ
O
1/4 SCALE FLUME
(I 1/2" PVC PIPE)
-POTABLE WATER
FILTERED CHILLER WATER
CONTROL VALVE
COLLECTION SCREEN
Figure 1. Simulated giblet flume (1/4 scale),
as shown by Lillard (1978) in
reference #5.
55 GAL. WATER
COLLECTION TANK
GIBLET
PUMP
-------
CHILLER
WATER
DIRECTION OF FLOW
CHILLER WATER
PRE-COATINGOF FILTER LEAVES
AGITATOR
D.E.
SLURRY
K3
O
PUMP
Figure 2.
INJECTOR
EXIT
PUMP
REGULATOR
CHLORINE
TANK
Schematic diagram of pre-coat tank, pressure leaf filter, and chlorinator.
Arrows show the line of flow. As shown by Lillard (1978) in reference #7.
-------
TABLE 3. CHEMICAL PROPERTIES OF CHILLER
AND FILTERED CHILLER WATER
Mean mg/1
(Based on 18 samples)
Water
Source
Chiller water
Filtered chiller water
(1:1 w/w Speedflow +
Dicalite 4200)
Percent reduction due
to filtration
Suspended
Solids
160
9
94
Dissolved
Matter
414
324
22
Grease
137
16
88
TABLE 4. MICROBIOLOGICAL QUALITY OF CHILLER
AND FILTERED CHILLER WATER
Source
Chiller water
Filtered chiller water
Filtered, chlorinated
chiller water
Mean log,_/ml
Aerobic
count
5.12
3.72
1.45
Fecal
coliforms
3.13
1.33
<0
No. of
samples
18
18
10
Microbiological quality of the water was further improved by chlorination.
Removal of organic matter from chiller water by filtration made it possible
to chlorinate effectively with low levels of chlorine gas (26-28 ppm)
instead of the 48-50 ppm required for untreated chiller water. Table 4
shows that after chlorination, filtered chiller water was comparable in
microbiological quality to potable water (7).
The filtered water was clear, and relatively colorless and transmitted
91-100% of light at 540 nm; it was not esthetically objectionable; and it
visually resembled potable water. Figures 3 and 4 show the extremes in
color and clarity of filtered chiller water compared to potable water.
208
-------
to
Figure 3. Water samples (left to right): from the bird chiller, filtered chiller water
and potable water as shown by Lillard (1978) in reference #7.
-------
to
H
a
Figure 4. Water samples (left to right) from the commercial flume, bird chiller, filtered
chiller water and potable water as shown by Lillard (1978) in reference #7.
-------
Fig. 3 shows the maximum color obtained; Fig. 4 shows the clearest water
obtained, with or without chlorination, which resulted in 100% light
transmission at 540 nm.
In Fig. 4 clarity of the filtered chiller water, unfiltered chiller water or
commercial flume water is best compared with that of potable water by the
ease with which markings on the beakers can be seen through the water. When
necks are flumed with potable water, the appearance of the water changes
within seconds of the necks entering the flume. Fig. 4 shows the dark
(bloody) characteristics of commercial flume water and the grease floating
on the surface. By contrast, filtered chiller water is relatively clear,
colorless and free of grease. Considering the chemical, physical and
microbiological properties of the filtered chiller water discussed above and
the rapid deterioration of potable water in the neck flume, the requirement
for use of potable water in neck flumes does not seem necessary.
Necks flumed in the simulated line with potable water were then compared with
necks flumed with filtered chiller water and with filtered, chlorinated
chiller water. Temperature of necks flumed with chiller water varied
seasonally. However, during the course of this study, necks flumed with
chiller water were 12 C cooler than necks flumed with potable water. Table
5 shows that, microbiologically necks flumed with potable water and necks
flumed with filtered chiller water or filtered, chlorinated chiller water
were not significantly different.
TABLE 5. MICROBIOLOGICAL CHARACTERIZATION OF NECKS FLUMED WITH
POTABLE WATER, FILTERED CHILLER WATER AND FILTERED,
CHLORINATED CHILLER WATER
Source of Mean logiO/ml
flume Aerobic.. Fecal - Mean number
water counts coliforms days of shelf-life
Potable water 5.48 a (12) 3.75 c (12) 14.2 e (30)
Filtered chiller water 5.45 a (12) 3.47 c (12) 14.2 e (30)
Potable water 5.17 b (10) 3.50 d (10) 11.7 f (25)
Filtered, chlorinated 5.27 b (10) 3.53 d (10) 13.0 f (25)
chiller water
The same lower case letter follows values which are not significantly
different at the 5% level. The number of samples per mean is given
parenthetically.
211
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CONCLUSIONS
In accordance with federal regulations and technology, giblets are flumed
with potable water. My work has shown that product quality can be equally
good when water of somewhat less than potable quality is used; necks flumed
with chiller water filtered through diatomaceous earth were microbiologically
equal in all respects to necks flumed with potable water. Fluming giblets
with filtered chiller water would reduce the demand of poultry processors
for potable water and energy, and also would reduce the amount of water and
organic matter discharged into municipal waste treatment systems.
According to estimates a processor could recover the cost of a pressure leaf
filter in less than 2 years (7).
REFERENCES
1. USDA. Poultry Inspection Regulations. U. S. Department of Agriculture,
FSQS, Washington, D. C. (1972).
2. Carawan, R. E., Crosswhite, W. M., Macon, J. A. and Hawkins, B. K.
Water and waste management in poultry processing. EPA Project 12060
EGV, Office of Research and Development, U. S. Environmental Protection
Agency, Washington, D. C. 20460 (1974).
3. Lillard, H. S. Microbiological characterization of water for recycling
in poultry processing plants. J. Food Sci. 42:168 (1977).
4. Lillard, H. S. Evaluation of bird chiller water for recycling in giblet
flumes. J. Food Sci. 43:401 (1978).
5. Lillard, H. S. Broiler necks flumed in recycled bird chiller water.
Po. Sci. 142 (1978).
6. Rogers, C. J. Unpublished data. "Recycling of water in poultry
processing plants," First Interim Technical Report, EPA Projects-800930.
Office of Research and Development, Industrial Environmental Research
Laboratory, U. S. Environmental Protection Agency, Cincinnati, Ohio,
45268.
7. Lillard, H. S. Improving quality of bird chiller water for recycling by
diatomaceous earth filtration and chlorination. J. Food Sci. In Press
(1978).
8. Lillard, H. S. Evaluation of broiler necks flumed with untreated or
diatomaceous earth filtered, filtered and chlorinated chiller water.
J. Food Sci. In Press (1978).
212
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DESIGN AND OPERATION OF A VEGETABLE OIL PLANT
WASTEWATER TREATMENT SYSTEM FOR FUTURE STANDARDS
by
N. J. Smallwood*
INTRODUCTION
Lou Ana Foods, Inc., operates a medium-size vegetable oil refining and
processing plant in Opelousas, Louisiana. The plant is operated continuously
except for shutdown on major holidays.
Because of ownership and management changes in the early 1970's, attention
was not directed to achieving compliance with the Federal Water Pollution
Control Act until 1975. It was then concluded that the company did not have
the technical resources to successfully handle the project. A search was
initiated to obtain the necessary expertise. By June, 1976, the company was
able to acquire the services of a competent consultant and recruit experienced
technical management who were able to utilize the best methods and designs
which had evolved from the vegetable oil industry. The result of the work
has been to meet the NPDES schedule of compliance and effluent limits, and,
we believe, to provide a system for meeting future standards. The purpose of
this presentation is to share with the vegetable oil industry and the
Environmental Protection Agency our concept, design, operating mode, results,
and conclusions pertaining to vegetable oil wastewater treatment.
SYSTEM OBJECTIVES
The scope and design of the Lou Ana Foods' wastewater treatment project were
to meet the following objectives:
1. Meet the NPDES schedule of compliance and effluent limits.
2. Achieve a level of reliability to not jeopardize continuity of plant
operations or exceed effluent limits.
3. Provide water treatment capacity for future expansion of production
facilities.
4. Minimize operating costs.
5. Improve the esthetic image of the plant.
6. Satisfy Spill Prevention, Control, and Counter Measure requirements.
7. Accommodate future effluent standards with minimum capital cost.
WASTEWATER EFFLUENT FROM VEGETABLE OIL PROCESSING
Sources and Characterization
The treatment system was designed to handle three categories of water effluent
from manufacturing operations:
*Vice-President, Operations, Lou Ana Foods, Inc., Opelousas, Louisiana.
213
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1. Process Wastewater: Water which has been in contact with the product
stream and contains some concentration of oil, processing reagents, and
sludge material derived from crude vegetable oil.
2. Rainwater Runoff: Rainwater which falls on outside surface areas and
initially washes away drips and spills from tank car and truck loading/
unloading stations and tank fields.
3. Non-Contact Cooling Water: Wellwater remaining free of contamination
while circulated once through a closed piping/coil system to maintain
process temperature control.
Water Stream Separation and Collection
The system includes the following separation and collection by category:
1. Process Wastewater: The wastewater from each major source is individually
piped for gravity discharge into a collection sump adjacent to the main
processing building. Routine, visual observation, sampling and analysis
can be made of each wastewater stream to detect anomolous conditions.
From the collection sump, the wastewater flows by gravity through an
underground line to the pre-treatment sump which is equipped with a
mechanical agitator.
2. Rainwater Runoff: Outside areas subject to oil leaks, drips and spills
are provided with concrete mats and dikes for containment. Underground
drainlines are installed for gravity flow of rainwater/oil to a collection
sump adjacent to the pre-treatment sump for process wastewater. The two
adjacent sumps have a connecting line for gravity flow from the rainwater
sump to the process wastewater sump. The connecting line contains a
remote operated shutoff valve actuated by a raingauge device. Thus, in
the event of a rain, the initial rainwater collected by the concrete mats
and dikes wash and carry away any oil spillage to the rainwater collection
sump and on to the process wastewater pre-treatment sump. If the rainfall
continues for a prolonged period, after a preset level is reached in the
raingauge, a signal is transmitted to a controller which will close the
valve in the connecting line between sumps. The water level in the rain-
water sump will rise until it reaches a high level overflow which will
conduct, by this time, essentially pure rainwater to the non-contact
cooling water outfall.
Note: If rainwater runoff were allowed to indefinitely flow into process
wastewater pre-treatment sump, then the subsequent treatment system would
be overwhelmed by the quantity of water. The other alternative of sizing
the subsequent treatment system to handle the complete rainfall load is
not economically feasible.
3. Non-Contact Cooling Water: Non-contact cooling water lines are piped to
discharge into a flash tank. Any steam generated will flash and vent to
the atmosphere. From the flash tank, water is pumped to two oil-water
separating decanters connected in series for removal of any entrained oil
which could result in event of coil failure. Clean water underflows from
the second decanter for gravity discharge through a weir box and a final
gravity separator and on to the non-contact cooling water outfall.
214
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TREATMENT TRAIN
The sequence of processes in the treatment train is pH adjustment, gravity
separation of floatable oils, flow equalization, neutralization, dissolved air
flotation, biological treatment and clarification.
pH Adjustment
A pH in the two to three range is required to achieve optimum gravity separa-
tion of floatable oils. Adjustment of pH is achieved by a control loop which
monitors the wastewater in the pre-treatment sump and controls sulfuric acid
addition to the sump for lowering pH as required.
Gravity Separation of Floatable Oils
Wastewater is pumped from the pre-treatment sump to four decanters for sepa-
ration of floatable oils. The wastewater stream enters the first two decanters
connected in parallel through a horizontal distributing nozzle located in the
center of each vessel. Oil-water separation occurs in the horizontal center
zone of each vessel with the floatable oil subsequently rising to the top of
the liquid column. The accumulation of oil is pumped off each day by means of
a swinging suction. The water fraction is continually drawn off by gravity
underflow to the second two decanters connected in series for repetition of
the process. Some of the solids in the wastewater stream settle to the bottom
of the decanters. The decanter system is sufficiently sized to operate suc-
cessfully with one parallel branch valved out of service for sediment removal.
Flow Equalization
Flow equalization for optimum operation of dissolved air flotation is achieved
by means of eight 12,000 gallon capacity hold tanks. The hold tanks provide
capacity for a minimum of 16 hours accumulation of wastewater at the present
flow rate of 85 gpm. Other than for flow equalization, the hold tanks function
as settling tanks for further removal of settleable solids and gravity separa-
tors for further recovery of floatable oil. The hold tanks can be individually
valved out of service for removal of accumulated floatable oil and sediment
without disrupting normal operation of the system.
Neutralization
Wastewater is pumped from the hold tanks to the dissolved air flotation
process. On the suction side of the transfer pump, caustic soda is injected
to neutralize the water stream. Primary neutralization control is provided
by an automatic control loop. Manual control is provided for backup operation.
Dissolved Air Flotation
Neutralized water and a cationic polymer coagulant are discharged into a two
compartment flocculation tank with high and low speed mixing agitators
respectively. From the flocculation tank, the water overflows to the inlet
of a center-positioned coagulation tube in the flotation cell. Water under-
flows from the flotation cell through six exterior riser tubes to a top
215
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peripheral collection ring for both recycle pressurization and gravity
discharge to an aerated lagoon. Water recycled at about 350 gpm is fully
pressurized and is injected with an anionic polymer coagulant aid prior to
discharge back into the coagulation tube. Removal of float is accomplished
by a top rotating skimmer. The DAF is sized to provide a surface loading of
less than 3.0 gpm/sq ft.
Biological Treatment
Biological treatment is accomplished by means of an aerated lagoon. The
lagoon capacity is 11.2 million gallons with a normal water depth of 16 feet.
A redwood baffle separates the lagoon into two sections. Aeration is achieved
by eight 40-horsepower floating aerators. Liquid fertilizer is injected into
the lagoon influent to supply nitrogen and phosphorus for the microorganism
life processes. The perimeter wall of the lagoon is concrete lined to preclude
erosion. At the present wastewater influent rate, the lagoon provides 90 days
of retention time.
Clarification
Treated water is pumped from the aerated lagoon to a clarifier for separation
of the biological sludge. The clarifier is sized for an overflow rate of
450 gpd/sq ft of surface area and a retention time of three hours. Clarified
water gravity flows to a final monitoring station. The biological sludge is
recycled back to the inlet side of the aerated lagoon.
Final Monitoring
Prior to discharge to the outfall, the treated water flows through a monitoring
station for flow measurement, sampling, and pU recording.
OPERATION
Time
With more than 16 hours hold capacity, the dissolved air flotation process
(DAF) is operated only eight hours per day. Furthermore, the clarifier is
operated and treated water is discharged only during the period that the DAF
is in operation. Operating the critical elements of the system only during
the day shift provides the opportunity for maximum attention and control.
Reliability
The treatment system in contact with acidic wastewater is constructed
primarily of fiberglass reinforced plastic (FRP). Consequently, it is essen-
tially maintenance free. Both pH control loops for sulfuric acid and caustic
soda addition respectively have backup manual control. Critical pumps in the
system are paired and are installed in parallel. Operation of the total
system would be seriously impaired only in the event of mechanical breakdown
of either the DAF or clarifier. However, up to 16 hours per day repair time
is available for both the DAF or clarifier. With excess retention time
available in the aerated lagoon, the DAF could probably be bypassed for up to
216
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five days without significant consequences. Sufficient freeboard is
available in the aerated lagoon to hold water for at least five consecutive
days to accommodate major repair of the clarifier.
RESULTS
Completion
Construction of the wastewater treatment system was completed and startup
achieved to meet the July 1, 1977, NPDES schedule of compliance.
Performance
Performance results from operating the treatment system eight months are given
in Table 1.
Project Cost
The total cost of the treatment system project was $1.5 million.
Operating Expense
Annual operating expense for the total system based on actual experience to
date is given in Table 2.
Reliability
The system has been operated continually since startup without any significant
problems. However, the necessity of manual pH control backup and other
reliability features described has already been demonstrated.
CONCLUSIONS
With disciplined operation and maintenance of the treatment system, it appears
that meeting BOD, O&G and pH limits will not be a problem.
It is too early in the life of the system to predict the expected long-term
performance on suspended solids removal. After the microorganism population
in the aerated lagoon has reached optimum level, it will be possible to better
access clarifier performance and suspended solids removal.
System performance can be further improved by optimizing treatment conditions
for each type of vegetable oil refined. Wastewater from cottonseed, corn,
soybean and sunflowerseed oil refining/acidulation is relatively easy to treat.
Coconut and peanut oil wastewater being more emulsified is more difficult to
treat.
Use of decanters and hold tanks for floatable oil and settleable solids removal
is assessed to be better than conventional fat traps or API type separators
in overall operation.
217
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TABLE 1. WASTEWATER TREATMENT SYSTEM PERFORMANCE
Effluent Characteristics for Treatment Train Processes
Process Concentration (mg/1)
COD BOD O&G TSS £H
1. Collection-pH Adjustment Sump 38,333 10,850 8,107 12,461 2.1
2. Decanter - - 2,635 9,014 2.1
3. Equalization - Hold 15,000 7,692 577 905 2.2
4. DAF 4,053 5,972 282 589 6.5
5. Aerated Lagoon 547 123 4 608 7.0
6. Clarifier 161 16 4 66 7.2
Performance for Each Treatment Train Process
Process Percent Removal
COD BOD O&G TSS
1. Decanter 0 0 67.5 27.7
2. Equalization - Hold 60.9 29.1 78.1 90.0
3. DAF 73.0 22.4 51.1 34.9
4. Aerated Lagoon 86.5 97.9 98.6
5. Clarifier 70.6 87.0 0 89.1
6. Total Treatment System 99.6 99.8 99.9 99.5
Treatment Performance with Respect to NPDES Limits
Minimum Average Maximum
Flow Rate (MGD) 0.066 0.121 0.178
BOD (Ib./day) 4 17 (104) 47 (256)
O&G (Ib./day) 1 4 (41) 10 (104)
TSS (Ib./day) 17 68 (104) 156 (256)
pH 7.0 (6.0) 7.2 7.4 (9.0)
Note: NPDES limit conditions given in parenthesis
218
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TABLE 2. ANNUAL OPERATING EXPENSE FOR THE TOTAL WASTEWATER TREATMENT SYSTEM
Expense Item Cost
1. Labor $29,370
2. Operating Supplies
a. Sulfuric acid 20,672
b. Caustic soda 34,712
c. Flocculant agents 24,000
3. Maintenance (Material & Labor) 27,000
4. Utilities
a. Steam 4,876
b. Electrical Power 49,304
5. Sludge Disposal 17,600
6. Miscellaneous 5,000
7. Depreciation 79,320
TOTAL $291,854
Wastewater Treatment Cost = $6.89/1,000 gallons
219
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Disposal of sludge from the treatment system is a challenging problem. We are
still seeking a satisfactory, long-term solution.
Overall, based on results achieved to date, it can be concluded that the
wastewater treatment system has and will continue to meet design objectives.
220
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DISSOLVED AIR FLOTATION TREATMENT
OF
GULF SHRIMP CANNERY WASTEWATER
by
A. J. Szabo, Larry F. LaFleur, and Felon R. Wilson*
INTRODUCTION
The plant scale dissolved air flotation project for treatment of a Gulf Coast shrimp can-
nery wastewater and other cannery pollution abatement measures are discussed. The sys-
tem was installed as a joint industry-government demonstration project to establish achie-
vable levels of pollutant removals from wastewaters during shrimp processing and during
oyster processing. This project was the follow-up of an earlier pilot study sponsored by
the American Shrimp Canners Association and the Environmental Protection Agency (1).
As reported by Ertz/etal/to the Eighth National Symposium on Food Processing wastes (2),
the dissolved air flotation process has been tested on a pilot scale for several seafoods and
has been installed full scale to treat tuna and other fish wastewaters. This treatment pro-
cess has advantages of minimal land requirements and quick start up, and is particularly
adaptable to the seasonal, intermittent operations of the land-poor Gulf shrimp processors.
Chemical coagulation and pH adjustment to precipitate colloidal and suspended solids in
proteinaceous seafood wastewaters for removal by flotation is considered to be a practica-
ble and presently available technology which could be substituted for the less adaptable
biological process. Plant scale system performance should, therefore, be of interest to in-
dustry and to regulatory and other governmental agencies.
BACKGROUND
Gulf shrimp canners have for many years been concerned with their wastewater disposal
problem. These processors have sought solutions individually and collectively. Several
manufacturers and suppliers have installed and operated test units, ranging from screening
and flotation to reverse osmosis. This project sought to develop practicable wastewater
management and treatment data from a plant scale installation under normal cannery oper-
ating conditions. The association (ASCA) obtained a demonstration grant and funded the
studies, design, installation and operation of the facilities at the Violet Packing Company
cannery south of New Orleans. Information obtained will be of assistance to all shrimp
processors in their pollution abatement programs.
Principal, Mechanical Engineer, and Sanitary Engineer, respectively,
Domingue, Szabo & Associates, Inc., Consulting Engineers, Lafayette, Louisiana
221
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CANNERY WASTEWATER
The Violet Packing Company shrimp and oyster processing and canning layout schematic
is shown in Figure 1. Wastewaters flows from unit processes were characterized at the
start of the study. Sources, volumes and concentrations as developed in 1975 are shown
in Table 1.
TABLE 1. UNIT PROCESS WASTEWATERS, GULF SHRIMP CANNERY
Flow
Process
Gallons/ M^/KKG % of
1000 IDS. Total
Concentration-mg/l
BODS O & G TSS
Receiving
Peelers
Separators
Graders
Deveiners
Canning Room
143
2,825
572
237
1,289
2,373
1.193
23.550
4.770
1.976
10.750
19.760
1.9
38.0
7.7
3.2
17.3
31.9
4,278
2,375
899
395
366
781
650
257
34
12
14
17
1,711
963
401
190
211
329
After study, a water conservation and wastewater management plan was adopted and the
cannery made considerable improvement which affected water use. Total wastewater
volumes were reduced by 43% from 7,728 gallons per 1000 pounds (64.4nrYKKg) of raw
shrimp processed to 4,420 gallons per 1000 pounds (36.9 mVKKg) between 1974 and 1977.
Cannery pollution abatement procedures resulted in the significant reduction of total pollu-
tants in the wastewater during this period.
The treatment facilities were designed to treat screened wastewater from the cannery at a
flow rate of 700 gallons per minute (2.6 mvminute). By the time the system was put into
operation, the flow had been reduced to 500 gpm (1.9 m3/minure). The concentrations
of the Violet Packing Company 1977 wastewater flows after pretreatment through 10 mesh
(0.85 mm) vibrating screens are given in Table 2.
222
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INSPECTION
a
SEPARATORS WEIGHING
OYSTER BOAr
DOCKING AREA
SHRIMP PRODUCT FLOW
OYSTER PRODUCT FLOW
WASTEWATER
VIOLET PACKING CO.
VIOLET, LOUISIANA
Figure 1
-------
TABLE 2. GULF SHRIMP CANNERY WASTEWATER CONCENTRATIONS
Parameter
BODS
Soluble BOD5
COD
Soluble COD
TKN
Oil & Grease
TSS
VSS
pH (Units)
Range
(mg/l)
450-1620
265-1120
1388-3920
1032-2960
156-344
28-169
240-1020
188-892
Average
(mg/l)
1070
720
2775
1880
260
115
505
425
7.5
As evident from the range of values in Table 2, the character of wastewaters from shrimp
canning operations is not consistent. The lack of uniformity is due to the variation in
size, age and type of raw product and to variations in processing rates and water use.
TREATMENT FACILITIES
A multi-modal dissolved air flotation system was installed at the Violet cannery in 1976.
It consisted of complete facilities to treat the cannery wastewaters in full flow pressuriza-
tion, partial flow pressurization or recycle pressurization modes. An influent flume flow
meter recorder-controller served to proportion chemical dosages. Acid (or caustic) dos-
ages into the influent surge tank were pH meter-recorder-controller actuated and equali-
zation flow was returned to this tank. Treatment process pumps pressured the injected air
and wastewater mixture into the retention tank at full flow mode or pumped into the floc-
culation tank in partial or recycle modes. Coagulant was added to the influent flume
and coagulant aid was injected into the flotation cell influent line downstream from the
manual pressure control valve and/or into the flocculation chamber. Wastewater entered
the circular flotation cell center coagulation chamber in which pressure was released and
the suspended solids-air bubble mixture moved upward and radially. Floated solids accu-
224
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mulcted on the surface as skimmings and were swept by four rotating scraper arms over a
beach and chute into the skimmings hopper. Clarified wastewater flowed radially and
downward to effluent tubes, up and over the circumferential weir and into the effluent
tank. Prior to discharge, pH was adjusted with caustic feed controlled by the effluent pH
meter-recorder.
In the partial flow pressurization mode, part of the flow (50%) was routed as above for
the full flow mode and the remainder of the wastewater flow was pumped to the vertical,
cylindrical floccularion tank with mixer, after pH adjustment and coagulant feed, for a
20 to 30 minute slow mix. It then flowed by gravity to the center, coagulation chamber
of the flotation cell where it was mixed with the pressurized flow containing coagulant
and coagulant aid.
Recycle pressurization was accomplished by routing all chemically treated influent waste-
water to the flocculation tank and pressurizing clarified flotation cell effluent through the
retention tank and into the coagulation chamber, where the dissolved air and flocculated
wastewater were mixed and released in the flotation cell. Figure 2 shows the DAF layout.
The DAF treatment system included storage tanks for liquid alum, liquid caustic, and con-
centrated sulfuric acid. The flow meter recorder-controller, pH controller-recorders, pro-
portioning chemical feeders for acid, alum and coagulant aids (two units), power supply
meter, and central panel were designed for system control and data collection. An on-
site laboratory was installed and equipped to enable analyses to be timely made.
OPERATIONS
In order to confirm pilot plant findings on chemical coagulant and coagulant aid dosages,
bench tests were made on Violet Cannery wastewater. Maximum precipitation and clari-
fication was repeatedly shown to occur at pH 4.5 to 5.0, although ranges from about 2. 0
to 11. 0 were investigated. Coagulants tested were: alum, chitin (chirosan), glucose tri-
sulfate (GTS), iron salts, lignosulfonate, and cationic polymer. Coagulant aids used
were: Magnifloc 835A and Magnifloc 845A, as recommended from the pilot study. Pro-
mising results were obtained with alum, lignosulfonate (PRA-1), and cationic polymer
(507C) as coagulants combined with polymers 835A and 845A.
Operation of the new DAF wastewater treatment system met with start up problems that
"just couldn't happen here". Completion of equipment delivery and installation was
about two weeks after start of the heavy canning season. Problems with the flow meter-
controller, chemical pumps, pH meter-controller, process pumps, flocculator, flotation
cell, and electrical system were slowly resolved while the supply of product was being
used up and was dwindling. By the time some of the equipment and installation difficul-
ties were resolved, the primary, summer season had passed. Other discrepancies in the
flotation cell coagulation tube and the inadequacy of skimming arms were rectified and
some operations were possible during the limited fall 1976 canning season. Other necess-
ary modifications were completed prior to the 1977 summer season so that full operations
225
-------
CANNERY
WASTEWATER
SCREENS
LEGE ND
SCREENINGS
TO-«
DISPOSAL
RAW WASTEWATER
FULL FLOW MODE
RECYCLE MODE
PARTIAL MODE
FULL FLOW a
PARTIAL MODES
AIR
SATURATION
TANK
RECYCLE 8
PARTIAL MODES
RECYCLE
MODE
AIR
PRESSURE
RELEASE
VALVE
ADJUST
SKIMMINGS
TO
DISPOSAL
TREATED
EFFLUENT
DAF TREATMENT PLANT SCHEMATIC
Figure 2
226
-------
and data collection were possible.
The dissolved air flotation treatment plant was first operated as a physical treatment sys-
tem, without any chemical addition. Limited removals of BOD5 and oil and grease were
accomplished, and solids existing in suspension were effectively reduced. Removals
attained were: BODS - 3.5%; Oil and Grease - 10.5% and TSS - 69.4%.
Physical-chemical treatment was the primary objective and most efforts were directed
toward obtaining optimum performance. In all circumstances, pH was controlled between
4.5 and 5. 0 by the addition of sulfuric acid. Coagulants were added to the system influ-
ent stream and coagulant aid was injected into the pressured flow entering the flotation
cell and/or into the flocculation tank. Effective pH control and coagulant-coagulant
aid additions resulted in significant removals of the conventional pollutants. Full flow
pressurization mode average removal performance levels are shown in Table 3 by types of
coagulant applied.
TABLE 3. DAF TREATMENT OF GULF SHRIMP WASTEWATER,
COAGULANT COMPARISON
Coagulant Coagulant Aid Per Cent Removal No.
-Dosage (mg/l) -Dosage (mg/l) BODS TSS O&G Test
Runs
PRA-1
60
507C
300
Alum
219
835A
2.5
835A
5.0
835A
3.9
56.7 73.3
68.5 56.8
48.5 62.7
67.7 3
71.1 2
87.3 23
Pressurization modes were compared using alum and polymer. Influent flow pH was adjust-
ed to 5.0, alum was added to the influent, and polymer was added to the pressure control
valve discharge. These data (Table 4) were collected under carefully controlled operating
conditions and reflect maximum attainable results.
227
-------
TABLE 4. DAF TREATMENT OF GULF SHRIMP WASTEWATER,
MODAL COMPARISON
Mode
Full Flow
Partial
Recycle
Overall
Average
Average
Alum
(mg/0
219
345
283
271
Average
835A
(mg/l)
3.9
6.1
7.5
5.8
PerCent
BOD5
48.5
55.0
64.6
56.5
Removal
TSS
62.7
72.6
64.8
65.6
O&G
87.3
83.4
83.6
85.0
It was realized that average industry treatment system operation could vary significantly
from the atypical project conditions. In order to simulate anticipated conditions, several
unattended, automated test runs in the full pressurization mode were sampled. Removals
achieved with average dosages of 303 mg/l of alum and 3.7 mg/l of polymer were:
BODS - 54.5%; TSS - 34.3% and O & G - 84%.
Because of the warm weather and the existing adjacent housing developments which pre-
vail at most Gulf shrimp cannery locations, it is necessary to take positive action to con-
trol odors and insects around the wastewater treatment system, and the total cannery.
The wastewater and the solids which are developed are highly putrescible and very odor-
ous. Frequent washdown and use of insecticides is necessary. Treatment system tanks
must be drained and washed when intermittent operations result in no fresh wastewater
flows for 8 to 12 hours or longer. The additional pollutants discharged under such condi-
tions can be calculated and cause further reduction in the effectiveness of the treatment
system operation.
Inherent characteristics of shrimp processing operations contribute to some of the condi-
tions which limit consistent and higher levels of achievable pollutant removals. Raw pro-
duct types and sizes and age variations, processing rate changes and adjustments, stop
and go and intermittent operations and possibly other factors are involved. The variable
wastewater flow was found to be extremely sensitive to coagulant dosages and frequent
adjustments were needed. The study plant air injection capabilities were limited. Air to
solids ratios may, therefore, not have been fully investigated in the operation of the de-
monstration plant., An additional air source would have been helpful.
Solids developed by flotation separation and skimming from the surface of the dissolved
228
-------
air system main cell consist of about 6% solids, air and liquid. These solid wastes are
highly odorous and objectionable and are difficult to store and handle. Bench scale tests
were made to concentrate the solids by centrifuging, by heating, and by gravity. Chemi-
cal conditioning with a bench scale Purifax unit demonstrated a degree of stabilization.
A pilot scale evaporator-dryer unit by Convap was operated. It appeared that skimmings
concentration to about 25% solids may be feasible, with a corresponding three fourths
reduction in volume. More investigation of waste solids handling, concentration and
disposal is urgently needed to solve this real problem of DAF system operation on seafood
wasrewaters.
COSTS
Computations have been made of costs of DAF system installation and operation to treat
Gulf shrimp processing wastewaters. These costs range from $0.38 to $1. 03 per case of
24-4 1/2 oz. (128g) cans of shrimp, depending upon the annual production. Costs for a
typical 8-peeler cannery are from $120,000 to $132,000 per year, varying with the num-
ber of days of operation, the amount of product processed and the volume of generated
wastewater which must be treated.
OYSTER WASTEWATER
The shrimp wastewater DAF treatment system was utilized to treat wastewaters from oyster
processing and canning for a four week period in early 1977. Flow rates were about one
fourth as great as while processing shrimp. Screened oyster wastewaters contained higher
suspended solids and lower concentrations of oil and grease and biochemical oxygen de-
mand. Mean values were: BODS - 510 mg/l; O & G - 37 mg/l; TSS - 2,280 mg/l and
settleable solids - 30 ml/1.
Operating without pH adjustment but with alum and polymer as coagulants, the DAF sys-
tem designed for shrimp cannery wastewater treatment was effective in reducing the dis-
charged pollutants. Mean percentage removals attained were: BODS - 43%; O & G -
56%; TSS - 89%; Settleable Solids - 99%.
SUMMARY
It may be concluded from this study that dissolved air flotation physical-chemical treat-
ment of shrimp processing and oyster processing wastewaters can be effective in reducing
conventional pollutants. Such a pollution abatement-treatment system for shrimp process-
ors should include a program of water use and wastewater management, pre-screening, a
recycle mode dissolved air flotation system with automated pH control, proportional coag-
ulant and coagulant aid feeders, and a suitable solids handling system. An effective,
satisfactory method of collecting, concentrating, storing, handling and disposing of
screenings and skimmings solids is yet to be developed and now appears to be a major
detriment to the effective operation of the DAF treatment system on shrimp processing
wastewaters.
229
-------
REFERENCES
1. Mauldin, A.F., and Szabo, A. J., Shrimp Canning Waste Treatment Study,
U.S. EPA - 660/2 - 74 - 016, June 1974.
2. Ertz, D.B., Atwell, J.S., and Forsht, E.H., "Dissolved Air Flotation Treatment
of Seafood FYocessing Wastes - An Assessment", Eighth National Symposium on
Food Processing Wastes, Seattle, Washington, 1977.
230
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UPGRADING A BREWERY
WASTEWATER PRETREATMENT FACILITY FOR
THE CITY OF WINSTON-SALEM
by
C.D. Malone*, R.M. Stein*, and T.D. Cornett**
INTRODUCTION
The malt beverage brewing industry produces in excess of 60 bil gal of waste-
water annually. A large percentage of this wastewater discharges into munici-
pal wastewater treatment facilities. Typical raw waste loads for the malt
beverage brewing industries are presented in Table 1. The quantity of oxygen
demanding materials and suspended solids generated requires a high level of
treatment. This treatment is normally provided either at the brewery or at
a municipal wastewater treatment plant. This paper reviews the treatment
system and operation program developed by the City of Winston-Salem, North
Carolina, for treatment of a brewery wastewater at the Archie Elledge Waste
Treatment facility. The City of Winston-Salem operates a 36 mgd activated
sludge waste treatment plant. The treatment plant provides both primary
and secondary treatment. Primary treatment consists of bar screens, grit
removal, and primary clarification; while secondary treatment consists of
four 200-ft diameter trickling filters followed by activated sludge and
chlorination. Excess biological and raw primary sludges are anaerobically
digested and subsequently dewatered on sand drying beds. The dried sludge
is applied directly to farm lands. Gas produced by anaerobic digestion
of the sludges is utilized to generate all electrical power requirements.
Figure 1 presents a schematic illustration of the Archie Elledge Waste
Treatment Plant.
Operational problems were experienced at the Archie Elledge plant, because
of an organic overloading of the secondary treatment system. The City and
and its consultant, AWARE, Inc., evaluated alternatives to reduce the organic
load to the secondary treatment facilities. The results of this evaluation
indicated that pretreatment of the brewery waste was the most practical
approach to the problem. Pretreatment of the brewery waste was selected for
two major reasons.
1. The City of Winston-Salem has a number of industries which dis-
charge concentrated wastes into the treatment system. Most indus-
trial wastes are combined with domestic waste and diluted before
reaching the treatment plant. The brewery waste discharges into
a separate outfall with only 100 private residences and thus
arrives at the treatment plant without significant dilution.
Thus, the brewery waste was segregated and arrived at the plant
as a concentrated stream.
*Associated Water and Air Resources Engineers, Inc., Nashville, Tennessee
**City of Winston-Salem, Winston-Salem, North Carolina
231
-------
PRE-TREATMENT
-f-
PRIMARY TREATMENT
-SLUDGE HANDLING FACILITY
lnl«fc«plor
S«w«r
PRIMARY SECONDARY SLUDGE
DIGESTER DIGESTER DRYING
BED
To Dupowl
FINAL CLARIFIERS
ACTIVATED SLUDGE
BASINS
NTERMEDtATE CLARIFIERS
—OSompling LocoHofl
UtaNMMr Floo
Slud0« Flow
- SECONDARY TREATMENT
FIG. I . SCHEMATIC ILLUSTRATION OF THE MUNICIPAL WASTE TREATMENT PLANT
-------
TABLE 1. TYPICAL RAW WASTE CHARACTERISTICS
FROM MALT BEVERAGE PRODUCTION
Brewing Industry
Mean Raw Waste Loads
Average Range per Bbl of Beerc
Raw Waste Volume 2649,5-30280 m3 971o46£/bbl beerb
Raw Waste BOD 1400-2000 mg/ia 1.37 kg/bbl beerb
Raw Waste Suspended Solids 500-700 mg/la .56 kg/bbl beer
(1622 mg/i)
> kg/bbl be<
(772 mg/1)
federal Guidelines, State and Local Pretreatment Guidelines, Construction
Grants Program Information, EPA-430/9-76-017c, January 19770
EPA Technology Transfer Series, Capsule Report 6, Pollution Abatement in
a Brewing Facility., Prepared by U0S0 EPA0
C0ne barrel contains 117„18 liters.
2. The potential for developing filamentous organisms could be re-
duced by pretreatment of a predominatly carbohydrate brewery
waste prior to the activated sludge system.
Table 2 presents a summary of the brewery raw wastewater characteristics
as it enters the Elledge plant. This discharge includes the brewery, the
brewery container manufacturing plant wastes, and a small domestic con-
tribution. The brewery wastestream comprises approximately 35 percent of
the total BOD loading to the waste treatment plant and approximately 10 per-
cent of the total plant flow.
The pretreatment system was developed in two phases. The initial phase of
the brewery pretreatment facilities, constructed in 1971, consisted of a
1.33 mil gal aerated lagoon with an installed horsepower level of 360.
The system was designed to treat a flow of 2.5 mgd. The effluent soluble
BOD from the basin averaged 450 mg/1 with a volatile suspended solids
level of approximately 850 mg/1.
In 1977, it was decided to expand and upgrade the pretreatment facilities
to accommodate the increased loadings and produce an effluent with a solu-
ble BOD level of less than 350 mg/1. Discussions with brewery personnel
indicated that with increases in production and expansion of the brewery
facilities, the average brewery wastewater flow could be expected to be
3.5 mgd with a BOD concentration of approximately 2,000 mg/1.
233
-------
TABLE 2. SUMMARY OF BREWERY RAW WASTEWATER CHARACTERISTICS
(a)
Parameter
Min.
BOD 1,011
SS 269
TKN
NH -N 4.1
3
NO -N 3.8
ALK 395
pH, units 5.7
1976
Avg.
1,509
546
Monthly
Average Values
1977
Max.
2,103
739
Min.
945
361
20
(c)
(c)
(c)
4.
3.
2
9
405
6.
9
(c)
(c)
(c)
4.
4.
3
1
414
7.
4
(c)
(c)
(c)
1.
0.
4
4
209
6.
9
Avg.
1,378
526
27.8
4.4
3.0
320
7.5
Max
1,777
773
46
12
15.5
402
7.7
o
All units are mg/1 except as noted.
Expressed as mg/1 of C^CO .
^ o
f*
Data shown for November 1976 and December 1976 only.
Prior to upgrading the treatment facilities, the operation of the existing
pretreatment system was reviewed. The objective of. this review was to
define problems in the operation of the brewery pretreatment system so
that solutions to these problems could be incorporated in the upgraded
facility. A discussion of some of the operational problems associated
with the treatment of brewery wastewaters is presented as follows.
OPERATIONAL CONSIDERATIONS
Significant variations in both the quantity and quality of brewery waste-
waters result because of batch processing and the seasonal fluctuations
in production schedules. Figure 2 presents the chronological variations
of the average monthly BOD and suspended solids loading to the Elledge
treatment plant from the brewing facilities. Peak production, as noted
by increased loadings to the plant, was during April through August,
which is consistent with historical data. These seasonal variations are
significant in the operation of waste treatment facilities from the stand-
point of:
234
-------
Q
UJ
Q
Z
UJ
O.
9,000
5,000
1 - 1
1 - h
t-0
U)
Ul
I
M
Q
§
20,000
10,000
M
M
j J
1976
O
N D
FIG. 2 MONTHLY VARIATION OF BREWERY WASTELOAD
-------
1. Equalization must be provided or the facility must be suffi-
ciently large to accommodate the peak loadings.
2. The high loadings increase oxygen demand on the treatment sys-
tem during the summer months.
Significant diurnal load variations are found in the brewery wastewater.
Figure 3 presents the diurnal variation in chemical oxygen demand (COD)
observed over a 48-hour period. The diurnal variations of COD during
this particular period ranged from 1,100 mg/1 to 2,600 mg/1. Figure 4
shows typical diurnal flow patterns from the brewery. Extreme diurnal
variations of pH are experienced due to the batch operation of the brewing
process and the necessity of thoroughly cleansing the equipment with caus-
tic wash solutions between brews. Figure 5 shows typical variations of
the wastewater pH during a 24-hr period and indicates the severity and
duration of the pH oscillations.
The wastewater as received from the brewery does not contain a sufficient
quantity of nitrogen to accommodate biological oxidation. It is, there-
fore, necessary to supply a supplemental nitrogen source to meet the
nutrient requirements of the microorganisms. Liquid agricultural nitrogen
(30 percent total nitrogen content) is purchased and metered into the
aeration basin. The cost of the nitrogen supplement amounts to approxi-
mately $36,000 per year. The varying organic load of the brewery waste-
stream requires constant monitoring of the nitrogen addition facilities
to ensure that an adequate nitrogen level is maintained.
Problems have been experienced because of excessive discharges into the
treatment system. Three major organic discharges including dextrose and
corn syrup have occurred at the brewery because of equipment malfunctions
and ruptured pipes. The largest of the discharges resulted in approxi-
mately 22,500 kg of dextrose entering the treatment facility. This organic
load to the aeration basin caused a rapid depletion of the dissolved oxygen
level in the pretreatment basin and subsequent reduction of treatment
efficiency. This resulted in high organic loads being transferred to the
plant proper with an ultimate deterioration of final effluent quality.
It took approximately three days for the system to recover from this shock.
The discharge of oil and grease into the collection system is another pro-
blem. The oil and grease originate from the metal cans manufacturing faci-
lity. Although no inhibitions to the biological systems have been observed
due to the oil and grease spills, fouling of the collection system and
pumping facilities has occurred. This results in a large manpower expendi-
ture in cleaning the transport facilities.
A frequently occurring problem encountered in the treatment of brewery
wastewaters is that of foam on the aeration basins. Foam layers 4-5 in.
deep have formed on the aeration basins and this is undesirable for several
reasons. The foam rises and flows out and onto the ground surrounding the
basins. The bio solids become entrapped in the foam and are also carried
out of the basin. This causes unsafe conditions and presents a potential
odor problem. Additionally, if the foam does not overflow the basins, the
236
-------
U)
•-J
3,000
2,500
2,000
O 1,500
1,000
500
1
12am 5am 10am 3pm 8pm
2-24-76
lam 6am 11am 4pm 9pm
2am
2-25-76
TIME, hours
FIG. 3 TYPICAL DIURNAL VARIATIONS OF BREWERY WASTEWATER COD
-------
NOTE: EACH UNIT ON THE GRAPH
REPRESENTS 1mgd
FIG. 4 TYPICAL DAILY FLOW PATTERNS FROM THE BREWERY
238
-------
FIG. 5 TYPICAL DIURNAL pH VARIATIONS
239
-------
solids have a tendency to accumulate and form crust layers on top of the
foam, again resulting in odor problems.
SIGNIFICANT DESIGN CONSIDERATIONS
Increased loadings on the Elledge treatment plant again overloaded in
the plant in 1976 ; therefore, it was decided to expand the brewery pre-
treatment process. This would relieve the plant of the increased brewery
loadings and allow the plant to receive and accommodate increased loads
from other industrial contributors. The objectives in upgrading the
brewery pretreatment system were:
1. To reduce the incoming organic waste load from the brewery.
2. To provide capabilities within the system to dampen and equalize
the quantity and quality of the brewery wastewaters.
3. To include the flexibility of operating the two-basin system
in either a series or parallel mode.
4. To examine the feasibility of utilizing anaerobic digester
supernatant as a nitrogen source.
Pilot aerated lagoon studies were performed and full-scale operating
data were evaluated to develop the process design criteria and the use
of digester supernatant as a nitrogen source. The results of these studies
are summarized in Table 3. Table 4 presents the average characteristics
of the digester supernatant. The results of the studies indicated that an
aerated lagoon could provide high levels of organic removal. The digester
supernatant proved an effective nutrient source. An effluent soluble BOD
of less than 350 mg/1 could consistently be achieved with the addition of
digester supernatant.
TABLE 4. SUMMARY OF ANAEROBIC DIGESTER SUPERNATANT CHARACTERISTICS
ARCHIE ELLEDGE WASTE TREATMENT PLANT
Parameter
COD, total (mg/1)
Solids (percent)
Volatile Solids (percent)
NH3-N (mg/1)
3
Flow m
Value
14,891
1.70
0.80
245.
946.25
240
-------
TABLE 3
SUMMARY OF PILOT PLANT PERFORMANCE
Parameter
BOD, total
BOD, soluble
COD, total
COD, soluble
SS
VSS
SS (ZSV Supernatant)
VSS (ZSV Supernatant)
TKN, total
TKN, soluble
NII3-N
pll (units)
MI.SS
MLVSS
1). T. days
0 Uptake, (mg/1 - min)
Temperature, °C
F/M (g/BOD/g MLVSS - day)
D.O.
Averaging Period
Value
Unit I(b)
Influent Basin Effluent
839 259
613 45
1,269 1,055
1,032 183
559 761
253 419
373
265
55
--
19 23
7.3 8.0" 7.9
872
513
1.21
0.28
20
1.35
5.4
2/1 to 23/77
(a)
Influent
839
613
1,269
1,032
559
253
—
--
55
--
19
7.3
Unit II(c)
Basin Effluent
198
23
857
167
807
475
188
133
—
—
26
8.1 7.9
863
516
2.31
0.23
20
0.70
5.4
2/1 to 23/77
Unit III(d)
Influent Basin Effluent
2,228 753
.1,267 220
5,580 2,606
2,063 467
3,200 2,435
1,878 1,337
367
240
213 31
29.5
45 13
7.0 7.8 7.8
3,348
] ,966
1.10
0.41
20
1.03
3.0
3/1 to 15/77
Unit IV(e^
Influent Basin Effluent
2,370 824
1,165 76
4,870 3,419
1,975 295
4,278 4,185
2,030 2,544
265
86
279
22
55 16
7.1 7.8 7.9
4,641
2,673
0.99
0.29
20
0.90
3.2
3/1 to 15/77
a) All units aie mg/1 except as shown, d) Unit at one day detention time, with P percent supernatant (based on influent flow).
b) Unit at one-day detention time. e) Unit at one-day detention time, with 13 percent supernatant (based on Influent flow).
c) Unit at two-days detention time.
-------
Tests were conducted to determine the rate of oxygen transfer into the
brewery wastewater relative to the oxygen transfer rate into tap water
(alpha tests). Several series of alpha tests were performed through
the course of the study. These results are summarized in Table 5. These
values, 0.6 to 0.7, are considered reasonable and were used for design.
TABLE 5. SUMMARY OF OXYGEN TRANSFER ANALYSES
Sample Location
and Date
Basin Effluent
(March 1976)
Basin Effluent
(March 1977)
Basin Influent
(March 1977)
Test Speed
RPM
150
225
300
100
200
288
100
200
288
(a)
Alpha Factor '
0.52
0.15
0.33
0.66
0.67
0.64
0.48
0.56
0.58
All values corrected to 20°C.
The microorganisms utilize oxygen for biological respiration. For brewery
waste treatment, (approximately 2.0 to 5.0 g 0~/g basin volatile solids-day
is required). This is very high when compared to rates for a typical acti-
vated sludge system of between 0.1 to 0.8 g 0,,/g basin volatile solids-day.
These two factors, low transfer rates and high oxygen uptake rates, result
in a large horsepower input to the basin, approximately 270 hp/mil gal of
basin volume. Typical activated sludge horsepower levels range from 100 to
150 hp/mil gal of basin volume.
DESIGN CONSIDERATIONS FOR OPERATIONAL FLEXIBILITY
Utilizing the results from the bench-scale tests, and data gathered from
the operation of the full-scale system, a process design was developed for
the proposed expansion. The design summary for the expanded facilities is
presented in Table 6.
Figure 6 presents a schematic illustration of the expanded facilities
employed for the pretreatment of the brewery wastewaters. Basin 1 was
first placed on line in 1971 and Basin 2 was put into service in October
1977. Total installed horsepower for both basins is 900.
242
-------
ANAEROBIC
SUPERNATANT
c
EFFLUENT
SAMPLE
POINT
LIQUID
NITROGEN
INFLUENT
SAMPLE
POINT
FROM
BREWERY
HOUSE
FLOW
PROPORTIONED
SPLITTER BOX
BASIN 1
VOL = 5,034m3
HP
= 360
T
BASIN 2
VOL = 8,327m3
VARIABLE
LEVEL
WEIR BOX
FIG. 6 SCHEMATIC ILLUSTRATION OF BREWERY PRETREATMENT FACILITIES
-------
TABLE 6. DESIGN SUMMARY
Parameter Value
AERATED LAGOON
Design Flow, m3 13,247.5
Influent BOD, mg/1 2,000
Effluent BOD, mg/1 350
3
Basin Volume, m
Existing Basin 5,034.05
New Basin 7,570
Aeration Horsepower, hp
Existing Basin 360
New Basin 540
Surge Capacity, m
Existing Basin 0
New Basin 2,460.25
Nitrogen Requirements, kg/day
Maximum 1,314
Average 1,026
The problem of fluctuating wastewater flow and load was addressed in the
process design. Approximately 0.65 mil gal of surge capacity was incor-
porated into the design of the new basin. The surge capacity calcula-
tions were predicated on providing additional equalization for the acti-
vated sludge basin in the plant proper. The surge capacity was achieved
by constructing a variable level discharge weir in the new basin. Using^
high-speed, floating aerators allows the water level to be varied approxi-
mately 2.5 feet (0.65 mg).
In the design of the new facilities, flexibility was incorporated to allow
the operation of the two basins in either a parallel or series mode.
Basin 1 is operated on a flow-through basis, while Basin 2 can be operated
at varying levels.
It was decided to utilize digester supernatant as a nitrogen source. Uti-
lizing the digester supernatant offers several advantages. The need to
purchase ammonia was eliminated resulting in a $35,000/yr savings. The
supernatant characteristically has pH in the range of 6.5 to 6.8. This
slightly acidic pH coupled with an alkalinity value of approximately
2,000 mg/1, as CaC03, helps to buffer the fluctuating pH received from
244
-------
the brewery. Additionally, the basin alkalinity as CaCO,. has increased from
approximately 225 mg/1 to approximately 450 mg/1. This affords a much
greater degree of protection from pH upsets. A pumping station was con-
structed and attendant piping installed (approximately 1,080 m at 20-cm
diameters).
The causes of foaming were evaluated and it was determined that the
foaming phenomenon results because of:
1. The high agitation levels within the basin (approximately
270 hp/mil gal.
2. Large volume of caustic wash solutions used at the brewery.
3. The foaming nature of the beer product itself. Operating
experience has found that the foam can best be controlled
with the use of commercially available defearning agents.
The problem of oil and grease discharges was resolved through the coopera-
tion of both the City and the brewery. The brewery has implemented pre-
treatment to capture oils.
TREATMENT PLANT PERFORMANCE
The new basin has been on stream since October 1977. Several mechanical
difficulties prevented full-scale operation prior to February 1978. The
first several weeks of operation are encouraging. Figure 7 presents a
chronological summary of various operational parameters. These data indi-
cate that the basin is consistently producing an effluent with a soluble
BOD level of less than 350 mg/1. Normally, effluent soluble BOD is in
the range of 200 mg/1. These data reflect parallel operations of the two
basins. Operation in a series mode has not been initiated.
The treatment of brewery wastewaters in a municipal waste treatment plant
presents some particular problems that must be addressed through design
and operation of the facility. The City of Winston-Salem has addressed
this problem and has developed a program to successfully treat brewery
wastes.
245
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BEGAN ADDING DIGESTER
SUPERNATANT
17
2 7 12
FEB MARCH
FIG. 7 CHRONOLOGICAL VARIATION OF PRETREATMENT
SYSTEM PERFORMANCE
246
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PHOSPHORUS REMOVAL AND DISINFECTION
OF MEAT PACKING LAGOON EFFLUENT
by
Richard T. Beaupre'* and Milton D. Redick*
INTRODUCTION
In order to comply with EPA and the State of Michigan wastewater effluent
limitations, the Feet Packing Company of Chesaning, Michigan, contracted with
Capitol Consultants, Inc., of Lansing, Michigan, for an engineering study to
determine alternatives for the upgrading of existing anaerobic-aerobic lagoon
facilities.
Preliminary design basis and cost estimates were generated for seven alter-
natives for additional BOD, SS, ammonia, and phosphorus removal as well as
disinfection. Based on modified discharge requirements by the Michigan
Department of Natural Resources, it was decided to proceed with design and
construction of phosphorus removal and disinfection facilities. Phosphorus
removal is to be attained with chemical addition and clarification. Due to
high ammonia levels of the wastewater, disinfection with chlorine dioxide
was chosen in order to reduce chlorine demand and to reduce the formation of
potentially harmful chlorine compounds. Construction of the facility is
nearing completion at this time.
BACKGROUND
The Peet Packing Company, Chesaning, Michigan, is a meat processing plant
which slaughters and processes an average of 1,050 hogs a day into fresh and
smoked meat products. The current employment at the plant is approximately
400 persons. The plant is located just north of the Village limits of
Chesaning, Michigan, and adjacent to the Shiawassee River, a tributary to
Lake Huron.
The principal meat products at the plant are fresh and smoked hams, sausages,
and luncheon meats. Raw beef is purchased from outside sources for inclusion
in these products. Additional daily processes are the rendering of fat into
edible lard, and the drying of blood into an agricultural product. By-
products consisting of all hog-viscera, condemned carcasses, parts of bones,
and lard rendering refuse are shipped to an independent Tenderer. Hair and
holding pen manure are also hauled from the plant.
*Capitol Consultants, Engineers, Inc., Lansing, Michigan
247
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The wastewater from Peet Packing Company varies greatly in both volume and
character throughout a normal operating day. Major wastewater streams are
hog and carcass rinse water from the kill floor, chill sprays from the cut
floor, scald tank dumping, sanitary sewage, boiler blow-down, compressor
cooling water, and plant cleanup chemicals and water. The majority of blood
is captured during the sticking operation and pumped to a dryer. The steam
condensate from the dryer contains blood residue which also adds to the
wastewater strength.
Original Wastewater Treatment Facilities
The original wastewater treatment facilities consisted of an anaerobic and
two aerobic ponds operated in series and with continuous discharge. The
ponds were constructed in 1967 and designed on an expected BODs loading of
750 kg (1,650 Ibs.) per day and a flow of 1,285 m3/d (340,000 gpd)(1). The
plant currently discharges approximately 640 m /d (170,000 gpd) to the
Shiawassee River in South Central Michigan.
Raw wastewater is collected at a large sump and pumped to the anaerobic
lagoon, a distance of approximately 245 m (800 feet). The lagoon is a clay
lined 3.7 m (12 feet) deep pond, with dimensions at the surface of 46 x 46 m
(150 x 150 feet), and with walls sloped 2 horizontal to 1 vertical. The
volume of the pond is 3,855 m3 (1,020,000 gal.); at a plant flow of 640 m3/d
(170,000 gpd), the average detention time is 6 days. A heavy layer of fat
and scum accumulates on the pond surface and maintains anaerobic conditions;
the layer also helps control odor and heat loss. The anaerobic lagoon has
two withdrawal pipes which empty to a wet well pumping station through a
siphon which maintains a constant pond depth. Wastewater is pumped from the
station a distance of 660 m (2,180 feet) to the aerobic lagoons.
The aerobic lagoons are 1.5 m (5 feet) deep clay lined ponds with a total
surface area of 5.9 hectares (14.3 acres). The walls have a slope of 3
horizontal to 1 vertical; freeboard at a 1.5 m (5 foot) depth is 0.9 m (3
feet). The volume of the ponds is 83,000 m3 (22,000,000 gal.); the average
detention time at a plant flow of 640 m3/d (170,000 gpd) is 130 days. The
aerobic ponds were designed for an average BOD5 loading of 33.6 kg/hectare/
day (30 Ibs./acre/day), or 196 kg/day (430 Ibs./day). Wastewater from the
aerobic ponds flows by gravity a distance of 460 m (1,500 feet) to the
Shiawassee River.
Lagoon Treatment Efficiencies
Table 1 is a summary of testing data from 1973 through 1977. Raw wastewater
samples, composited during the slaughtering operation, were collected by
Peet Packing and tested for BOD5 once a week from 1969 through July of 1975.
The results of these tests vary widely from BODs's of 800 mg/1 to over
10,000 mg/1. Raw wastewater sampling is very difficult, however, in that
large pieces of fat or tissue cannot adequately be accounted for, nor do grab
samples account for lower flows and strength during non-slaughtering hours
and weekends. The figure of 2,000 mg/1 is the best estimate of the overall
average weekly raw wastewater strength.
248
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Grab samples of anaerobic lagoon effluent were also tested on a weekly basis
by Peet Packing. This data showed the lagoon effluent BOD5 to normally vary
from 150 mg/1 to 700 mg/1, with peaks of up to 6,700 mg/1 when the blood
dryer was not in operation. The temperature of the effluent varies between
29° C. (85° F.) in the summer and 14° C. (57° F.) in the winter. The pH
varies from 6.3 to 7.5 with most readings below 7.2. The data collected
indicates a typical reduction in BOD5 of from 80% to 85% through the
anaerobic lagoon. References (2), (3), and (4) show typical removal rates
of 80% at other meat packing anaerobic lagoons. Of significant importance
is the increase in ammonia content over the raw wastewater due to the decom-
position of meat pieces and the conversion of organic nitrogen.
The aerobic lagoon effluent quality has been defined by weekly sampling of
BOD5 prior to 1975, and in addition, weekly sampling of suspended solids,
total phosphorus, ammonia as N, and oil and grease since that time. The
data shown in Table 1 are presented in time periods to demonstrate the
influence of periods of shut-down of the blood dryer and the freezing over
of the aerobic lagoons. During periods of blood dryer shut-down all blood
is included in the wastewater stream and lagoon loadings are increased by a
factor of ten. In order to alleviate this large overloading, the company
has recently made provisions to haul blood from the plant when the dryer
requires repair. Figure 1 is a plot of average monthly BOD5 and the data
indicates a significant deterioration of quality during winter months; how-
ever, during all of the past winters, the blood dryer has not been in
operation for periods of up to a month, and during January and February of
1975, the anaerobic lagoon was dredged out. Thus the freezing of the ponds
appears to have a significant influence on 8005; however, the extent is not
known.
The aerobic ponds have typically produced a BOD5 reduction of from 60-90%,
with the 90% rates occurring when the ponds were at normal loadings of 34
kg/ha/day (30 Ibs./acre/day) or less. The overall average loading of the
aerobic ponds, however, has been 40 kg/ha/day (36 Ibs./acre/day) with peaks
up to 740 kg/ha/day (660 Ibs./acre/day) when the blood dryer was shut-down.
In addition to hauling blood when it cannot be dried, the plant has also
been attempting to install a hydrasieve screen to eliminate pond over-
loading. The six month period of from June, 1976 to December, 1976, illus-
trates an average final effluent quality of 38 mg/1 BOD5 and 70 mg/1 S.S. is
achievable. These concentrations would result in an average discharge to
the River of 25 kg/day (54 Ibs./day) BOD5 and 45 kg/day (99 Ibs./day) S.S.
at 640 m3/d (170,000 gpd).
Figure 2 is a plot of average monthly phosphorus concentration based on
weekly sampling, and fecal coliform counts based on monthly sampling. The
average monthly phosphorus concentrations follow a nearly identical pattern
as the effluent BOD5 shown in Figure 1, except with a less dramatic varia-
tion. The variation in phosphorus may, however, be due to algae uptake and
release. Fecal coliform counts have been below the required July 1, 1977
NPDES permit levels much of the time, but appear to jump higher coinciden-
tally with the blood evaporator shut-down and initial heavy BOD discharge.
249
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TABLE 1
SUMMARY OF WASTEWATER QUALITY DATA
JULY, 1973 TO MAY, 1977
PEET PACKING COMPANY, CHESANING, MICHIGAN
Sample
Raw
Waste-
water
Anaerobic
Lagoon
Effluent
Aerobic
Lagoon
Effluent
Sampling
Period
7/73-7/75
7/73-7/75
8/75-12/75
1/76-5/76
6/76-12/76
1/77-5/77
BOD5
mg/1
7/73-7/75 2,000
360
163
36
182
38
251
81
101
70
102
Fecal
Phos. NH3 Coliform Flow
mg/1 mg/1 f/100 ml m3/d mgd
19* 7*
25* 55*
25*
16
24
21
32
55*
61
75
48
69
2,400**
800
2,900
300
40
720
680
640
490
640
0.19
0.18
0.17
0.13
0.17
Fecal Coliform Samples: 1 grab per month
Remaining Samples: 1 grab per week
*0ne sample.
**Five samples.
Effluent Limitations
The effluent limitations for the Peet Packing Company were determined based
on the most stringent of two criteria: the water quality standards of the
Michigan Department of Natural Resources and the EPA "Meat Products Point
Source Category Effluent Guidelines and Standards"(5). The Peet Packing
Company is categorized as a "High-Processing Packinghouse". The water
quality standards require an average 8005 of less than 36 kg/day (80 Ibs./
day) and 80% phosphorus removal; EPA limitations based on LWK (live weight
killed) resulted in limitations of 3005 of less than 36 kg/day (80 Ibs./
day), T.S.S. of less than 46.9 kg/day (104 Ibs./day), fecal coliform counts
of less than 400/100 ml, and oil and grease of less than 20 kg/day (44 Ibs./
day) with daily maximum limits less than twice that of the average. The
original effluent limitations also included a maximum ammonia discharge of
8 mg/1 during the period May 1 through October 31, with a pH limitation
between 6.0 and 7.5. The ammonia limitation was later dropped by the
Michigan DNR.
250
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cc
o
is
(E
O
Q_
Ld
Q
CO
a
o
o
Q
tr
o
LJ
Q
§
no
(T
O
Q.
UJ
o
o
300-
l-n
ru
1977 PERMIT LEVEL
80**/DAY
36 KG. / DAY
CO
CD
Q
O
m
600
500
400
300
200
100
23456789
1974
10 II 12 I 2 3 4 5 6 7 8 9 10
1975
12 I 23456789 10 II 12 I 234567
1976 1977
Figure 1. BOD5 of anaerobic lagoon effluent.
-------
to
FECAL COLIFORM
AVERAGE MONTHY
PHOSPHORUS
CONCENTRATION
1977 FECAL COLIFORM
PERMIT LEVEL
400/100 ML
8 9 10 II 12 I 2 3 4 5 6 7 8 9 10 ,11 12 I 2345678
- 4000
3000 g
oc
£
- 2000
o
u
o
LU
- 1000
Figure 2. Fecal coliform and phosphorus of aerobic lagoon effluent.
-------
WASTEWATER TREATMENT ALTERNATIVES EVALUATED
Preliminary design basis and cost estimates were generated for seven alter-
natives for upgrading the anaerobic-aerobic lagoons at the Peet Packing
Company. The alternatives were to provide additional BOD, S.S., ammonia,
and phosphorus removal, as well as disinfection. All of the alternatives
evaluated utilized biological treatment for BOD, S.S. and ammonia removal.
The most severe limitation for treating the wastewater was the ammonia
removal requirement. Ammonia can be converted to nitrate by nitrifying
organisms but their activity is hindered by low temperature and substantial
BOD reduction must take place prior to their becoming effective(6).
The first four alternatives included complete treatment at the Peet Packing
Company utilizing the existing anaerobic lagoon with the aerobic lagoons
used as a backup system. Additional biological treatment after the aerobic
lagoons was not considered because it was felt the very low discharge
temperatures of 2° C. (35° F.) during the winter and 7° C. (45° F.) during
April would inhibit establishment of ammonia removal prior to the May 1st
requirement. The fifth alternative considered pretreatment following the
anaerobic lagoon with discharge to the Village of Chesaning Municipal
Wastewater Treatment Facility.
The design basis for treatment after the anaerobic lagoon was as follows:
Flow 1,134 m3/d (0.3 mgd)
D.O. 0 mg/1
BOD5 500 mg/1
S.S. 300 mg/1
NH3-N 50 mg/1
P 25 mg/1
The sixth and seventh alternatives were to utilize both the anaerobic lagoon
and aerobic lagoons. The sixth alternative was to provide additional
storage for intermittent discharge during the winter months only, when river
flows are greater and 80% ammonia removal was required, rather than removal
to a level of 8 mg/1. The seventh alternative was land application with
border strip irrigation.
The major design parameters, capital cost and annual cost for each of the
alternatives are summarized as follows. The capital cost estimates were
for 1976, and include engineering and contingencies. The annual cost esti-
mates include amortization of the capital cost at 8% interest over 20 years,
labor, power, chemicals, testing, sludge handling and maintenance.
253
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Alternative 1 — Rotating Biological Disc
This system required 55,800 m2 (600,000 ft.2) of media on 6 shafts, six 5 HP
drives, fiberglass covers for the shafts, a pre-aeration basin with 4 hours
detention time to restore D.O., a clarifier, a chlorine contact chamber, an
aerobic sludge digester, and a control building with chemical storage. Some
of the advantages of a rotating disc system are low power cost, ease of
operation and low maintenance cost. The total estimated cost of the system
was $767,000, with a total annual cost of $136,200.
Alternative 2 - Extended Aeration Activated Sludge
An extended aeration system required a 2,270 m^ (600,000 gal.) circular
aeration basin, three 50 HP compressors, two clarifiers, a chlorine contact
chamber, an aerobic sludge digester, and a control building with chemical
storage. The aeration unit required 48 hours detention time and a solids
retention time greater than 10 days in order to achieve nitrification. In
order to achieve long solids retention times, a high solids recycle was
required for the first clarifier which would not be conducive for phosphorus
removal. Therefore, a separate clarifier was proposed for phosphorus pre-
cipitant settling. A dome cover was also proposed to minimize heat loss
and control odor problems. The total estimated cost of the system was
$769,600, with a total annual cost of $156,500.
Alternative 3 - Oxidation Ditch
An oxidation ditch system required a 2,840 m^ (750,000 gal.) looped trape-
zoidal channel, two 5.5 m (18 foot) long rotor aerators with a 30 HP drive
for each, two clarifiers, a chlorine contact chamber, an aerobic sludge
digester and a control building with chemical storage. The oxidation ditch
was to provide a minimum of 48 hours detention time and 10 days solids
retention time. The advantage of the oxidation ditch system was a lower
capital cost and ease of maintenance; however, odor control would be more
difficult, and lower wastewater temperatures would result. The total esti-
mated cost of the system was $590,000, with a total annual cost of $118,200.
Alternative 4 - Pure Oxygen Activated Sludge
A pure oxygen system required a closed chamber, 15 m (50 feet) square and
3-5 m (10-16 feet) deep, containing a BOD5 removal cell with a 7-1/2 HP
mixer, a clarification cell, an ammonia removal cell with a 5 HP mixer, and
a second clarification cell for phosphorus removal. The system also
required a pre-aeration tank, an aerobic digester, a chlorine contact
chamber, and a control building with chemical storage. Pure oxygen would
be supplied from a liquid oxygen storage tank which would require filling
every 2 months by a truck delivery. The major advantage of a pure oxygen
system is the limited space required. The total estimated cost of the
system was $764,600, with a total annual cost of $158,100.
254
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Alternative 5 - Pretreat and Discharge to Municipal Wastewater
Treatment Plant
The discharge of industrial waste to a municipality is governed by EPA
"Pretreatment Standards"(7), which require that an industry remove any
waste pollutant which would not be removed by the municipality. Since the
new Chesaning plant did not have design capacity for ammonia removal, the
high ammonia content of Peet Packing could be considered "incompatible" and
require removal to a level acceptable for direct discharge to the River
(Section 128.133). Discharge to the Village therefore required an oxidation
ditch, one clarifier for solids retention, an aerobic sludge digester, a
control building, modification of the existing pumping station, and 823 m
(2,700 feet) of 20 cm (8 inch) force main. The total estimated cost of the
Peet Packing system was $534,300, with a total annual cost of $140,000.
However, the Chesaning plant also required expansion to accommodate the
increased waste load. The Village of Chesaning, at that time, had received
an EPA Step 3 grant for 75% of the project cost and had just taken construc-
tion bids for major treatment plant expansion which did not include capacity
for the Peet Packing Company. The Village therefore would have had to
either abandon their grant and begin Step 1 and Step 2 planning anew or pay
for the additional expansion with 100% local financing. It was therefore
decided it would be too costly in terms of rewriting the facilities plan,
redesigning the plant and implementing industrial cost recovery, to proceed
with joint treatment.
Alternative 6 - Additional Treatment with Seasonal Discharge
This system required an additional 4.6 hectares (11 acres) of aerobic ponds
plus an oxidation ditch, two clarifiers, an aerobic digester, chlorine con-
tact chamber, and a control building with chemical storage. The total cost
of the system was $734,800, with a total annual cost of $139,400.
Alternative 7 - Land Disposal—Border Strip Irrigation
The border strip irrigation system required an additional 2.5 hectares (6
acres), 3.7 m (12 foot) deep storage pond for winter storage and 21 hectares
(50 acres) of irrigation cells plus an additional 61 m (200 ft.) border for
isolation. The irrigation cells would receive 5 cm (2 inches) of wastewater
per week over 6 months of the year. Each of 74 bermed cells, 15 x 183 m
(50 x 600 feet), would be flooded at 3.8 m3/min. (1,000 gpm) for approxi-
mately 30 minutes once a week. Alfalfa hay would be grown on the land for
nutrient removal and crop recovery income.
The design basis for the land disposal system was:
Flow 760 m3/d (200,000 gpd)
BOD5 60 mg/1
S.S. 90 mg/1
NH3-N 50 mg/1
P 25 mg/1
255
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A series of monitoring wells were anticipated to ensure that the proposed
application rates would not result in nitrate contamination of the ground
water.
An initial hydrogeological investigation of existing well logs in the area
indicated a site adjacent to the existing lagoons suitable for such a
system(8). Initial cost estimates also showed the alternative to be the
most economical. A site study was therefore initiated which showed a clay
layer 1.2-1.4 m (4-4.5 feet) below the surface with perched water at 0.9 m
(3 feet) or less below the surface indicating poor drainage(9). A clay
layer is advantageous in a land disposal system as it protects the ground
water below it from possible contamination; however, a minimum of 2.4-3 m
(8-10 feet) is needed above the clay to provide good drainage and bacterial
reduction of the wastewater. The proposed site was therefore unacceptable
and the sand fill necessary to make the site acceptable made the cost
totally prohibitive. In addition, an alternate site within 3.2 km (2 miles)
of the aerobic lagoons was not apparent.
WASTEWATER TREATMENT RECOMMENDED
The initial indications of the study were that land application would be the
most advantageous alternative. After further hydrogeological investigation
showed the site to be unacceptable, the oxidation ditch alternative became
the most cost-effective solution for BOD, S.S., and ammonia reduction.
Following completion of the initial study, the NPDES permit was modified in
part in that the ammonia removal requirement was deleted. The revised per-
mit still required upgrading of the existing lagoon facilities to provide
80% phosphorus removal and disinfection. Further removal of BOD5 and sus-
pended solids was also required. Since BOD and S.S. discharge appeared to
reflect breakdowns of the blood evaporator and a raw waste "Hydrasieve" was
not yet in use, it was felt that significant improvements in the BOD5 and
suspended solids levels of the final effluent could be achieved by operation
of the screen and by hauling blood to another suitable disposal facility
during periods of repair to the blood evaporator.
Thus the proposed system to meet the July 1, 1977, effluent limitations was
phosphorus removal by chemical addition and clarification, and disinfection
by chlorine. This system would treat the effluent from the existing aerobic
lagoons and discharge to the River by gravity. A flow schematic is shown in
Figure 3.
The system was to consist of a 9.2 m (30 foot) diameter clarifier with a
center flocculation zone, a chlorine contact tank, a sludge storage tank,
chemical storage and feed equipment and a control building. The system was
to have capability for the addition of either alum or ferric chloride in
conjunction with a polymer.
It was anticipated that 80 to 90% of the phosphorus could be removed along
with up to 60% of the algae, 50% of the BOD5, and 50% of the suspended
solids. Sludge storage would be provided and sludge would periodically (2-3
256
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DIVERSION
STRUCTURE.
NJ
Ul
sues
PUKPPIT
TO TRUCK
FILL STATION
SLUDGE
DBA* OFF PIT
EXISTING
OUTFALL MANHOLE
EXISTING SEWER
FROM AEROBIC PONDS-N
- ^15: /
CHEMICAL FEED POINT
• n» . •rl-'X. 1 TO RIVERA
CHLORINE DIOXIDE
FEED POINT
QiLDBINf
CONTACT
TANK
FLUME
0 VALVES
SLUCE GATES
STOP PLATES
-TO ANAEROBIC LAGOON
Figure 3. Process flow schematic for phosphorus removal
and disinfection.
-------
times a week) be removed by tanker truck and spread on farmland. The esti-
mated cost of the facility was $226,000, with an annual cost, including
amortization, of $55,000.
PROCESS DESIGN
Phosphorus Removal
Phosphorus removal from wastewater by chemical addition and clarification
has become common at municipal wastewater plants throughout Michigan and
other Great Lakes States. Phosphorus removal following lagoon treatment,
however, has not been practiced extensively as it has not yet been required
of small municipalities with lagoons. However, pilot studies for the City
of Ludington, Michigan, demonstrated that similar design bases can be used
for lagoon removals as for secondary biological treatment (10) .
The precipitation reaction of phosphorus with any metal ion is similar to
that of aluminum ion which can be expressed as follows :
A13+ + P043~ - - A1P04 |
which gives a mole ratio of A1:P of 1:1 or a weight ratio of 0.87:1. How-
ever, the reaction and physical settling is dependent on interf erring
reactions, coagulation requirements, pH, and temperature, which necessitate
chemical addition in excess of the 1:1 mole ratio of A1:P for efficient
removal. The results of published studies of phosphorus removal with alum
indicates that 80% phosphorus removal typically requires a mole ratio of
between 1.5 and 2. 3(11) (12) (13) (14) (15) (16) .
The chemicals used in phosphorus removal usually provide ions of aluminum or
iron, or calcium. Aluminum ion is usually supplied by aluminum sulfate
(alum), Al2 (504)3' 14H20, or by sodium aluminate, Na2Al204 or NaAK^. Iron
is usually supplied by ferric chloride, FeCl3» or ferrous sulfate, FeS04 or
ferric sulfate, Fe2(S04)3. Calcium ion is usually supplied by lime, CaOH2
or CaO. Waste alum sludge from water treatment plants and waste pickle
liquor from steel production have also been used for considerable cost
reduction. Alum was chosen to be used at Peet Packing because of its
availability and because it is somewhat less corrosive than ferric chloride.
Polymer addition can enhance coagulation of the phosphorus precipitate and
thus increase removal efficiency. Optimum dosages appear to vary greatly
with the type of polymer used and wastewater characteristics, dosages
between 0.2 and 1.0 mg/1 are common. A flocculation system will also
enhance the coagulation of the phosphorus precipitate with velocity gradi-
ents of 50 sec.~l typical.
The settling equipment for phosphorus removal at Peet Packing includes a
9.2m (30 foot) diameter clarifier with a 3 m (10 foot) side water depth, a
2.6m (9 foot) center flocculation well with a variable speed mechanical
258
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turbine type flocculator, sludge collector and surface skimmer arms, scum
box, weirs and baffles. A control building houses a 18.9 m3 (5,000 gal.)
chemical (alum) storage tank, a .49 m3/d (130 gpd) diaphragm type chemical
feed pump, a .57 m (150 gal.) polymer storage tank with wetting funnel, a
mixer, and a .17 m3/d (45 gpd) diaphragm type polymer feed pump. A non-
potable water pump recycles clarified effluent for dilution water for both
the alum and the polymer.
A telescoping valve allows withdrawal of clarifier sludge to a thickening
tank from which a second telescoping valve can be used to decant the super-
nate back to the clarifier. Thickened sludge can then be transferred to a
submersible pump sump from which it can be recycled back to the clarifier,
pumped to a truck fill station, or pumped back to the anaerobic lagoon.
Additional related equipment provided includes a 10 cm (3 inch) flume for
flow measurement and recording, and a flow proportional composite sampler.
The typical dosage requirements for 80% phosphorus removal were estimated
assuming a 1.7 mole ratio of A1:P, a 20 mg/1 influent phosphorus concentra-
tion, and a flow of 756 m3/d (200,000 gpd) as follows:
756 m3 1.000 kg 20 kg P 27 kg Al , , ,
- x T—°- x , ~i°— x „., °—— x 1. 7 mole ratio x
day mj 10° kg 31 kg P
594 kg Alum m3 .4 m3 _ 16.8 liters
x
or
54 kg Al 611.3 kg Alum day hr.
200,000 gal. 8.34 Ibs. 20 Ibs. P 27 Ibs. Al
——a x x ir.f. . — x 01 • — x 1.7 mole ratio x
day gal. 10° Ibs. 31 Ibs. P
594 Ibs. Alum gal, of Alum _ 106 gal, of Alum
54 Ibs. Al X 5.1 Ibs. Alum ~ day
Based on an estimated cost of $0.21 per gallon, the expected cost of alum
will be $22.60 per day or $8,250 per year.
Disinfection
Disinfection with chlorine is utilized throughout the country; however,
recent awareness of potential formation of harmful chlorine compounds and
residual toxicity in the stream, combined with the high ammonia levels of
the Peet Packing effluent, led to the investigation of alternate methods of
disinfection.
Chlorine dioxide was chosen because it does not combine with ammonia to pro-
duce chloramines, it is a stronger oxidant than chlorine(17), and it has
the potential for disinfection at smaller dosages than chlorine solution.
When chlorine is added to a wastewater, it rapidly combines with ammonia to
form monochloramines, dichloramines and trichloramines, all of which are
termed combined chlorine residuals. The monochloramines and dichloramines
have reduced disinfecting power and are extremely slow reacting(18), and it
may take up to two hours contact time to be useful as a disinfectant(19).
259
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"Free chlorine" is a term used for hypochlorous acid (HOC1) which is a
stronger, much faster acting disinfectant. Some estimates indicate dis-
infection capability of monochloramine is approximately one-one hundredth
that of free chlorine(19) . In order to obtain a "free chlorine residual"
in wastewater containing ammonia, enough chlorine must be added to result in
"breakpoint chlorination" which requires a minimum of 10 mg/1 of chlorine
for every 1 mg/1 of ammonia (19) (20) . In drinking water treatment, "break-
point" chlorination is a common practice to ensure complete disinfection.
In wastewater disinfection, it usually is not necessary to "breakpoint"
chlorinate to achieve the disinfection levels required (based on fecal
coliform); however, since chlorine dioxide is a disinfection agent equiva-
lent to "free chlorine", it has the potential for achieving the required
disinfection levels at a much smaller dosage.
The generation of chlorine dioxide requires the mixing of a chlorine solu-
tion and sodium chlorite (NaC102). The reaction is as follows:
2 NaC102 + Cl2 — - 2 C102 + 2 NaCl
In theory therefore, 1.00 kg of chlorine dioxide requires 1.34 kg of pure
sodium chlorite and 0.5 kg of chlorine (19) . Since sodium chlorite is
typically manufactured 80% pure, 1.68 kg of sodium chlorite is required and
an overdose of chlorine is used to ensure a complete reaction, therefore a
1:1 ratio by weight of chlorine to sodium chlorite is recommended (19 ). The
procedure is to pump a sodium chlorite solution with a metering pump through
a glass clyinder filled with porcelain rings; the cylinder is also fed
chlorine solution from a standard chlorinator. When the proper amount of
chlorine is added to the sodium chlorite solution, the mixture turns
greenish yellow providing visual indication of the formation of chlorine
dioxide. Sodium chlorite is shipped dry and should be mixed with water to
a convenient strength daily.
The typical chlorine dioxide dosage requirements for the Peet Packing
Company were estimated assuming 2 mg/1 chlorine dioxide would provide a
sufficient fecal coliform kill. With a flow of 760 m3/d (200,000 gpd) , the
estimated feed rates can be calculated as follows:
760 m3 1,000 kg x 2 kg C102 = 1.5 kg C102
day m-3 10° kg day
1.5 kg C102 1.68 kg NaC102 required = 2.5 kg NaCIO?
day X kg C109 day
. .,2.5 kg Cl?
for a 1:1 ratio also provide - -r3 - ^
inn nnn j 8.34 Ibs . 2 Ibs . C102 3.3 IbS. C102
or 200,000 gpd x - - x 1Q6 lbs> - - -
3.3 Ibs. CIO? 1.68 Ibs. NaCIO? required = 5.5 Ibs. NaCIO?
day X Ibs. C102 day
260
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and for a 1:1 ratio also provide —^ 2.
v day
Based on an estimated cost of sodium chlorite and chlorine of $0.80 and
$0.20 per pound, respectively, the expected cost of year-round disinfection
would be $5.50 per day or $2,020 per year.
It is difficult to estimate the required dosage of straight chlorine to
achieve disinfection at the Peet Packing Company; however, an estimated
usage of 20 to 30 mg/1 is not unreasonable considering the 50-60 mg/1 of
ammonia present in the effluent. The estimated chlorine usage at 20 to
30 mg/1 would be 15-23 kg/day (33-50 Ibs./day) and the expected cost of
year-round disinfection would be $6.60 to $10.00 per day or $2,400 to $3,650
per year.
The actual cost savings for the use of chlorine dioxide on a high ammonia
waste will only be shown through operational experience; however, the
potential is significant and the additional capital cost to provide the
capability to generate chlorine dioxide in addition to normal chlorination
equipment is modest. At Peet Packing the additional diaphragm metering
pump, 105 gallon tank, tank stand, solution diffuser,-generator (glass
cylinder), back pressure valve, pressure relief valve and anti-siphoning
valve had a total cost of $2,300.
Additional related equipment includes a PVC chlorine dioxide (or chlorine)
diffuser located in a flow channel prior to the flow measurement flume and
following clarification, and two concrete contact chambers 3 m long x 1.2 m
wide x 2.4 m deep (10 ft. long x 4 ft. wide x 8 ft. deep) each, of which
will provide 35 minutes contact time at a flow of 760 m^ (200,000 gpd).
Redwood planks are used for baffling to provide an over and under flow
pattern and to avoid short circuiting.
It should be noted that dry sodium chlorite requires special handling in
that it is flammable when it is in contact with organic material such as
gloves, sawdust, brooms, etc., and can ignite with heat or friction(19).
No danger is involved in handling the material if care is exercised and
precautions are followed, such as large amounts of flushing water should be
used to wash down any spills. Sodium chlorite once mixed with water pre-
sents no further hazard.
It should also be noted that test samples tested once a month over a 2 year
period indicate that the fecal coliform counts of the aerobic lagoon efflu-
ent remain below the 400/100 ml discharge requirement much of the year, and
usually only go above that level when the aerobic ponds are frozen over.
This indication also needs to be verified, however, as during warmer months
algae interference with the membrane filter test used has been noted and may
be creating erroneous results.
261
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CONSTRUCTION SUMMARY
The construction of the wastewater treatment facility was advertised for
competitive bids in two steps. Since the clarifier equipment, including
weirs and baffles, required the longest delivery time, bids for this equip-
ment were solicited prior to completion of plans and specifications for the
remaining portions of the facility. Proposals were received from three
manufacturers in January, 1977, and the equipment was awarded to the lowest
bidder. Following completion of plans and specifications, an "invitation
for bids" was advertised. Included in the contract documents was an assign-
ment of the previously accepted clarifier equipment to the contractor's bid,
this made the equipment supplier responsible to the contractor. The Peet
Packing Company chose to do all of the electrical and instrumentation work
with plant personnel. Construction bids were received in March, 1977, and
the contract was awarded to the lowest bidder at $193,000. Construction
began on May 1, 1977, and was substantially complete by October 31, 1977.
INITIAL OPERATING EXPERIENCE
Difficulty in getting the facility fully operational has been experienced
due to hard winter weather; however, alum and polymer have been fed for
phosphorus removal for the majority of the period between November, 1977,
and the time of this writing, March, 1978. A limited amount of data has
been analyzed during this period using "Standard Methods"(21). It appears,
however, that 80% phosphorus removal can be achieved using the original
estimated alum dosage of 1.7:1 mole ratio of A1:P. This dosage is equiva-
lent to a 1.5:1 weight ratio of A1:P, or 25 liters alum per kg incoming
phosphorus (3 gal. alum/lb. incoming P) assuming an alum solution of 1,332
kg/m3 (11.1 Ibs./gal.) A12(804)3-1^20 with 60 kg/m3 (0.5 Ib./gal.) Al.
The alum/phosphorus sludge characteristics observed have been very encour-
aging thus far, as the sludge both settles and thickens well. No disinfec-
tion data has yet been attained.
CONCLUSIONS
1. An evaluation of the disinfection of a lagoon effluent with high ammonia
concentrations indicates that the use of chlorine dioxide is not only
more environmentally sound but potentially less costly than disinfection
with chlorine.
2. Phosphorus removal from lagoon effluent can be reliably achieved with
chemical addition and clarification. Chemical requirements are similar
to those experienced at secondary municipal treatment plants, and
sludge characteristics appear to be excellent.
3. An evaluation of alternatives for ammonia removal indicated that land
application utilizing border strip irrigation was more economical than
mechanical treatment if an appropriate site can be found. Of a number
of mechanical treatment alternatives evaluated, an oxidation ditch
system appeared to be the most economical.
262
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REFERENCES
1. Spicer Engineering Company, "Report on Waste Treatment for Peet Packing
Company, Chesaning, Michigan", January (1966).
2. Dart, M. C., "Treatment of Waste Water from the Meat Industry", Pro-
cess Biochemistry, June (1974).
3. Witherow, "Waste Treatment for the Small Packer", The National Pro-
visioner, Vol. 169, No. 13, p. 8-14, September 30 (1973).
4. Witherow, "Waste Treatment Evaluation", The National Provisioner, Vol.
169, No. 14, p. 15-23, October 6 (1973).
5. E.P.A., "Meat Products Point Source Category Effluent Guidelines and
Standards", Federal Register, Vol. 39, No. 41, p. 7894-7908, February
28 (1974).
6. E.P.A., "Nitrification and Denitrification Facilities", Technology
Transfer Seminar Publication (1973).
7. E.P.A., "Pretreatment Standards", Federal Register, Vol. 38, No. 215,
p. 30982-30984, November 8 (1973).
8. Hilty, Robert D., "Hydrogeological Investigation Phase I, Peet Packing
Company", Keck Consulting Services, Inc., September 11 (1975).
9. Hilty, Robert D., "Hydrogeological Investigation Phase II, Peet Packing
Company", Keck Consulting Services, Inc., October (1975).
10. Williams, T. C. , and Malhotra, S. K., "Phosphorus Removal for Aerated
Lagoon Effluent", J. Water Pollution Control Federation, Vol. 46, No.
12, December (1974).
11. E.P.A., "Process Design Manual for Phosphorus Removal", Technology
Transfer (1971).
12. Long, D. A., Nesbitt, J. B., and Kountz, R. R., "Soluble Phosphate
Removal in the Activated Sludge Process—A Two-Year Plant Scale Study",
Presented at the 26th Annual Purdue Industrial Waste Conference, Purdue
University, Lafayette, IN, May (1971).
13. Hais, A. B., Stamberg, J. B., and Bishop, D. F., "Alum Addition to
Activated Sludge with Tertiary Solids Removal", AICHE Symposium Series,
Vol. 68, p. 35 (1972).
14. Directo, L. S., Miele, R. P., and Masse, A. N., "Phosphate Removal by
Mineral Addition to Secondary and Tertiary Treatment Systems", Pro-
ceeding of the 27th Industrial Waste Conference, p. 369, May 2, 3, and
4 (1972).
263
-------
15. Zenz, D. R., and Pivnicka, J. R., "Effective Phosphorus Removal by the
Addition of Alum to the Activated Sludge Process", Proceedings of the
24th Industrial Waste Conference, p. 273-301 (1969).
16. Baillod, C. R., Cressey, G. M., and Beaupre1, R. T., "Influence of
Phosphorus Removal on Solids Budget", J. Water Pollution Control
Federation, Vol. 49, p. 131-145 (1977).
17. Weber, Walter J., "Physicochemical Processes for Water Quality Con-
trol", Wiley-Interscience, New York (1972).
18. Metcalf & Eddy, Inc., "Wastewater Engineering", McGraw-Hill Book
Company, New York (1972).
19. White, G. C., "Handbook of Chlorination", Van Nostrand Reinhold Co.,
New York (1972).
20. Sawyer, C. N., and McCarty, P. L., "Chemistry for Sanitary Engineers",
McGraw-Hill Book Company, New York (1967).
21. APHA, AWWA, and WPCF, "Standard Methods for the Examination of Water
and Wastewater", 13th Edition (1971).
264
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PHYSIOCHEMICAL TREATMENT OF RENDERING WASTEWATER
BY ELECTROCOAGULATION
by
Ernest R. Ramirez* and Odgen A. Clemens*
ABSTRACT
A large rendering plant processes between 500 and 700 tons of material per
day. It handles feathers, fats, various forms of meat, etc. in a Carver-
Greenfield rendering operation. This unit produces approximately 1000 M^
per day of wastewater, while the air scrubber discharge, feather cooling
water discharge, and cooling tower overflow account for 871 M^/day, 757
M^/day and 246 M3/day, respectively. The 1000 M3/day from the rendering
operations is processed through a two-step electrocoagulation system before
it is discharged to the city.
The wastewater treatment operation uses both sulfuric acid additions as well
as alum for coagulation. The process is operated close to the zero zeta
potential (zero surface charge) of the pollutant particulates. Extremely
high reductions in suspended solids (97%) and fats and oils (98%) are
achieved with the two-step electrocoagulation technology.
Skimmings are dewatered in the same basin in which they are formed by using
dissolved air dewatering. Their solid content lie between 13.7 weight per-
cent and 17.5 weight percent.
INTRODUCTION
A large rendering plant in North America processes approximately 600 tons
of renderable material per day. The plant has only one objective; that
involves rendering. Wastewaters from the plant are discharged to the
municipality and subsequently to a river. The municipality has established
guidelines for receiving plant discharge and has set the following figures
as acceptable for effluent from a wastewater treatment system:
A. Suspended Solids - not to exceed 200 mg/1.
B. Hexane Extractables - not to exceed 100 mg/1.
C. BOD was not included in the restriction list.
The guidelines also specify that the limits established are for water leav-
ing the pretreatment system. Dilution with other waters, such as cooling
waters, etc., would not be considered as a measure of reducing pollutants
in the water.
* Swift Environmental Systems Company, Oak Brook, Illinois
265
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The local environmental agency also specified that spills and other mishaps
in the plant will not be permitted to influence the restrictions estab-
lished. In this regard it became mandatory to include a recycle system in
the pretreatment unit should these mishaps occur. This safeguard is carried
out by turbidimetric control.
Material rendered at the plant includes carcasses, bone fragments, hair,
feathers, etc. Discharge waters leaving the plant must fall within the pH
range of 5.5 to 9.5 units.
Odor problems encountered at the plant included that of ammonia mercaptans
and hydrogen sulfide. Ultimately it was understood that these odors would,
in due time, also be eliminated by proper treatment procedures. Management
decided that it would be more intelligent to handle the problems piecemeal
and start by first treating the wastewater to meet discharge permit guide-
lines. (This decision was, indeed, unfortunate.)
Plant Equipment and Wastewater Sources
The heart of the rendering plant consists of a Carver-Greenfield rendering
unit. Wastewaters leaving the Carver-Greenfield overall operation pass
through a natural flotation-sedimentation basin having dimensions of 9 feet
wide by 40 feet long by 5 feet deep. This basin has both a top skimmer
device as well as a bottom drag. Waters entering this sedimentation-
flotation basin emanate from: (a) feather condensates, (b) feather pit,
(c) truck wash, (d) Carver-Greenfield condensates, (e) raw material pit,
(f) blood system, (g) Carver-Greenfield ejector condensates, and (h) miscel-
laneous floor washings, etc. A breakdown of the water volumes and their
pollutant loading is given in Table 1.
TABLE 1. WASTEWATER SOURCES ENTERING NATURAL FLOTATION-SEDIMENTATION BASIN
Feather Condensates
Feather Pit
Truck Wash
Carter-Greenfield (C.G.) Condensates
Raw Material Pit
Blood System
C.G. Ejector Condensates
Miscellaneous, Floor Wash, Etc.
GPD
approxi.
10,000
21,000
16,000
70,000
21,000
30,000
100,000
20,000
BOD5
Total
mg/lt
6,540
4,430
2,270
4,210
10,200
57,000
700
2,500 '
SS
mg/lt
2250
5320
527
1510
4100
910
-
4100
FOG*
mg/lt
20
-
126
800
2100
60
-
2210
Total
* Fats, oils and grease.
288,000
266
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Another three sources of wastewater present at the plant are given in Table
2. These wastewaters do not pass through the natural flotation-sedimenta-
tion basin and will be discharged directly to the city.
TABLE 2. OTHER DISCHRAGE SOURCES IN PLANT
Air Scrubber
Feather Cooling Water
Cooling Tower Overflow
M3/Day
Volume
871
757
246
GPD
Volume
230,000
200,000
65,000
BOD5
Total
mg/lt
-
-
~
SS
mg/lt
270
-
300
FOG
mg/lt
15
-
~
In summary, four principal wastewater sources emerge from the plant. These
are: flotation-sedimentation basin, air scrubber discharge, feather cooling
water discharge, and cooling tower overflow. Total water discharge from the
plant is in the range of 2974 M^/day (780,000 GPD). The rendering plant is
primarily concerned with the wastewater in the natural flotation-sedimenta-
tion basin which represents approximately 1000 M^/day. The analyses of
these wastewaters are given in Table 1.
Optimum Treatment Determination of Rendering Wastewater
Wastewaters from the air scrubber discharge, feather cooling water dis-
charge, and cooling tower overflow will not be treated by the LectroClear
installation. These waters will simply be added to the discharge from the
LectroClear operation.
In evaluating the wastewater, the following three steps were carried out
using a batch-type two-step portable LectroClear unit together with a
streaming current detector.
A. Determination of the pH of zero streaming potential (also zero
zeta potential).
B. Determine the minimal treatment of alum or ferric sulfate to meet
goals (one liter samples).
C. Determine the optimum cost effective dosage for treating the
wastewater to comply with the established discharge guidelines of
less than 200 mg/1 of suspended solids and less than 100 mg/1 of
hexane extractables (one liter samples).
A series of analyses were carried out on the wastewater from the natural
flotation-sedimentation basin on different dates. In each case a composite
sample was taken. The results of these analyses are shown in Table 3.
267
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TABLE 3. ANALYSES OF WASTEWATER LEAVING
NATURAL FLOTATION-SEDIMENTATION BASIN
BOD5
Sample 1
Sample 2
Sample 3
Total
mg/lt
7480
7800
4800
Soluble
mg/lt
3400
3500
1470
SS
mg/lt
4475
2720
3280
FOG
mg/lt
880
740
820
Determining pH for Zero Zeta Potential
A streaming current detector (manufactured by Waters Associates, Inc.*) was
used to determine the surface charge on the pollutant particulates. This
was done by taking small 50 cc aliquot samples and determining the stream-
ing current value at various pH values. Sulfuric acid was used for pH
adjustment. Results of this study are shown in Figure 1. These results
clearly show that the surface charge on the pollutant particulates average
approximately zero at a pH of 4.2. Also shown is that, as the pH is reduced
and as it approaches 4.2, the charges on the pollutant particulates become
less and less. The reduction in surface charge (negative) encourages the
particulates to agglomerate and aggregate. On letting this wastewater
stand (at pH 4.2) for 1/2 hour, it was found that most of the pollutants
agglomerated and either floated or sank. The supernatant liquid had a
Jackson Turbidity Value of 500 units. This fact confirms that at a zero
streaming potential the tendencies for pollutants to agglomerate are indeed
appreciable. The relationship between the amount of acid needed to adjust
pH as a function of pH is shown in Figure 2.
Power requirements needed to satisfactorily treat the wastewater at a zero
zeta potential when only sulfuric acid is used as the coagulant (and 6 ppm
anionic polymer) are shown in Figure 3. The results of Figure 3 show that
the wastewater can be reduced to a turbidity of 300 Jackson Turbidity Units
by the application of 5 ampere minutes (at 12 volts) per liter of wastewater
processed. A detailed analyses of the treated wastewater at 5 ampere
minutes per liter are shown in Table 4. Because this operation is carried
out at a zeta potential approximately equal to zero, it is being referred
to as LectroClear-Z.
* 16 Fountain Street, Farmingham, Mass.
268
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LECTRO-CLEAR Z TREATMENT
STREAMING POTENTIAL VS. pH OF RENDERING WASTEWATER
ho
a\
vo
FIG.
PI-II. ELECTRODES
RUN AT 87 *F
NO USE OF METAL COAGULANT
(PH ADJUSTMENT ONLY H?S 04)
-------
RENDERING WASTEWATER (7-5-77)
pH
to
^J
o
4.5 -
4.0 -
FIG. 2
40O
800 1200
H2S04(ppm)
1600
2000
-------
Electrolytic Power Input As A Function Of Turbidity
At pH Of Zero Surface Charge (Acid)
10,000
JTU
5,000 H
500-
FIG. 3
I. ph«4.2
2.HeS04 Adj. Only (1500 mg/lt)
3. No Metal Coagulant
300JTU
1.0 2.0 3.0 4.0
Ampere Minutes/It
5.0
-------
TABLE 4. TREATING RENDERING WASTEWATER WITH
ELECTROCOAGULATION AT ZERO ZETA POTENTIAL
Sample
Description
Rendering
Wastewater
Treatment
(a) H2S04 to
pH 4.2
(b) 6 mg/lt of
anionic polymer
(c) 5 ampere min/1
SS (mg/lt)
Influent Effluent
FOG (mg/lt)
Influent Effluent
3680
310
750
80
Treating Rendering Wastewater with Trivalent Metal Coagulants Only
It was found that the rendering wastewater could be satisfactorily treated
to a zero surface charge when 500 ppm of ferric sulfate or 500 ppm of alum
were used in the treatment. Under these conditions, the pH of the waste-
water was reduced from its original value of 7.4 to a value of 6.2. With
this treatment the wastewater could be satisfactorily treated with a power
input of 2 ampere minutes (at 12 volts) per liter. Analysis of the waste-
water so treated is given in Table 5. The turbidity of this wastewater was
found to be 50 Jackson turbidity units. Since this process uses only a
metal coagulant (and an anionic polymer of 6 mg/lt), it is referred to as
LectroClear-M. (Figure 4).
TABLE 5. TREATING RENDERING WASTEWATER WITH
ELECTROCOAGULATION AND FERRIC SULFATE
Sample
Description
Rendering
Wastewater
Treatment
SS (mg/lt)
Influent Effluent
FOG (mg/lt
Influent Effluent
(a) 500 mg/lt
Ferri Floe
(b) 6 mg/lt
anionic polymer
(c) 2.0 ampere min/lt
3680
32
750
15
It will be noted that in this particular wastewater the LectroClear-Z
process has higher chemicals costs than does the LectroClear-M operation
(see Figure 5). Power input to obtain satisfactory results are also con-
siderably higher in the case of the LectroClear-Z method. The most cost
effective chemical treatment, however, is achieved by combining the use of
sulfuric acid in addition to a trivalent metal coagulant. Consequently,
the most cost effective operation taking into account chemicals is deter-
mined by using equation 1 for a series of satisfactory treatments.
272
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Electrolytic Power Input Vs Turbidity
At Zero Surfoce Charge (Trivalent
Metal Coagulant)
FI6. 4
1,000-
500-
. pH»6.2
2.6ppm anionic polymer
3. Ferric sulfate 500mg/lt
0.5 1.5 2.0
Ampere Minutes/It
273
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|/3.7»8
GRAPHICAL DETERMINATION OF MINIMUM
COSTS FOR LECTRO CLEAR-Z-M
(EQUATION I)
NO
POLYMER
0 250 500
500 400 300
,
6.1
5.8 5.4
750 1000 1250 1500 H2S04 mg/lt 66* Be
250 170 100 25 ALUM mg/lt USED
CHEMICALS USED
5.0 4.6 4.5 4.2 PH
-------
Equation 1 - Chemical Costs
$/1000 gal = $/3.788M3 = .00834 [AxB+CxD+ExF]
where:
A = mg/lt trivalent coagulant used
B = $/lb trivalent metal coagulant
C = mg/lt sulfuric acid used
D = $/lb delivered H2S04
E = mg/lt polymer used
F = $/lb polymer used
for plant in question:
B = $.09/lb
D = $.03/lb
F = $2.50/lb
E = constant 6 mg/lt
Most Cost Effective Treatment
By using equation 1 in conjunction with laboratory data, one arrives at the
results given in Figure 5. In essence, all treatments given in the abscissa
of Figure 5 treat the wastewater satisfactorily. The results show that the
most cost effective treatment is 500 mg/lt H2S04 (66° Be), 300 mg/lt alum
and 6 mg/lt of anionic polymer. Chemical cost of this treatment for the
plant in question is $.476 per 3.788 M3 (1000 gallons).
The most cost effective treatment in plant A may not necessarily be so at
plant B. Different cost of chemicals at different plants will necessarily
lead to different cost effective treatments. It is, therefore, necessary
that each plant determine its cost effective treatment based on chemical
costs in existence at that plant. Hardness of the wastewater has an over-
whelming effect on the most cost effective treatment. The wastewater at
this plant was highly buffered with organic salts. This accounts for the
exceptionally large amounts of acid needed. (See Figure 3.)
BASIC PRINCIPLE OF ELECTROCOAGULATION
The theory and principle of operation of the two-step electrocoagulation
technology has been adequately described in prior literature (1, 2, 3, 4,
5, 6). A summary of the process, however, is given below. The technology
involves two steps, the first having a duration of approximately 2 minutes.
This step is called coagulation and the container in which it takes place
is referred to as the coagulation cell or contact cell. A cardinal point
of this first-step operation is that coagulants are added to the wastewater
prior to the entrance into the coagulation cell. Likewise, pH adjustments
are also made prior to the coagulation cell. Microbubbles in the diameter
range of 50 to 100 microns are introduced into the coagulation cell at a
concentration of 1 million to 100 million microbubbles per liter of waste-
water. The 2-minute dwell time in the coagulation cell allows for intimate
collisions between the pollutant particulates and the microbbubles. These
275
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collisions result in a pairing off of particulates with microbubbles. Upon
leaving the coagulation cell, a polyelectrolyte is added and, at that
point, a gross floe is formed in the flotation basin. This gross floe has
entrapped in it better than 80% of the microbubbles generated in the coagu-
lation cell. It is these microbubbles which provide buoyancy to the floe.
The flotation basin is the second step of the electrocoagulation technology.
It involves a dwell time of approximately 25 minutes and electrolytic micro-
bubbles are again used to float particulates to the surface of the water
where they are subsequently skimmed off by a mechanical skimmer. A schema-
tic of this two-step operation using electrolytic power is shown in Figure
6. While this paper deals with electrolytic power, both dispersed air and
dissolved air microbubbles can also be effectively used in both the coagula-
tion cell and the flotation basin. When electrolytic power is used, cur-
rents in the range of 1.3 ampere minutes/It (5 ampere minutes per gallon)
are used in the coagulation cell and approximately 1 ampere minute/It (4
ampere minutes per gallon) in the flotation basin. Voltages employed are DC
and in the range of 10 to 15 volts. The fact that the process actually
treats the wastewater twice (once in each of the two steps) accounts for
the improved treatment results over and above that attained in a dissolved
air or electroflotation basin alone.
DESIGN CRITERIA AND CONSTRAINTS
The plant management has established that it would be important to have the
skimmings with a minimum of water. The reason for this requirement is the
plant has plans to render the skimmings for their protein and fat values.
High water content would require higher rendering energy inputs and require
a more costly operation. In view of this requirement, it was decided to
dewater the skimmings in the basin itself. This is carried out with the
use of dissolved air. The operation takes place in the electroflotation
basin itself and is restricted to the first quartile of the basin, namely
just as the skimmings are about to leave the basin.
For dewatering to be effective there must be a skimmings blanket height of
no less than 3 inches; a skimmings height of 4 inches or more is preferred.
Under these conditions it would require that the skimmer arms be placed on
a timer system whereby they would move 2 minutes out of every 4 minutes.
(This ratio is not fixed but is a variable depending on the plant in ques-
tion. )
The use of large amounts of metal coagulant (500 ppm) generally produces
skimmings of higher water content and overall greater volume. Because of
the constraints placed by the rendering operation, it was decided to use a
LectroClear-Z-M operation where only a small amount of trivalent metal
coagulant was added (less than 100 ppm).
Since management has decided that the skimmings would be rendered, it was
decided to use the LectroClear-Z-M process where only a small amount of
metal coagulant is added.
276
-------
FIG. 6
SCHEMATIC-RENDERING
.(EMBRYO FLOC)
CONTACT) &Ji
CELL /i REV. /
ISO' 1
ism*.!
LECTRO-CLEAR
TANK
-------
The plant management also felt that the use of the natural flotation-sedi-
mentation basin will not be changed because substantial amounts of readily
renderable fat were obtained from this operation. In this regard, the
unit pays for its keep and, therefore, will not be altered.
In summary, it was decided that the final wastewater treatment design would
consist of a LectroClear-Z-M unit which would incorporate a dewatering unit
in the first quartile of the flotation basin. Both an electrocoagulation
cell and an electroflotation basin would be used in the operation. Manage-
ment further expressed the desire to obtain a stand-by dispersed air device
as a source for microbubbles in the coagulation cell. This means that the
electrocoagulation unit could be run either with electrolytic energy or
mechanical energy (dispersed air). A failure in the rectifier would cer-
tainly make this decision worthwhile.
FINAL DESIGN
The final design for the LectroClear unit installed in this plant has a
capacity of 1.14 M^ (300 gallons) per minute. It consisted of the follow-
ing:
A. One coagulation cell with a 2-minute retention time having an open
top vortex chamber. The cell housed 90 Duriron TA-2 electrodes
each 7 feet long. Surface-to-surface vertical spacing between
electrode pairs is 3/8 inch. Horizontal spacing (surface to
surface) between a set of electrode pairs is 2.5 inches. Recti-
fier for the electrocoagulation cell is 2000 amps with a maximum
voltage setting of 20 volts. (See Figure 7.)
B. A dispersed air device precedes the coagulation cell and will be
used on a stand-by basis. Motor used for the dispersed air
device is 2 horsepower. (See Figure 8.)
C. The electroflotation basin is 8 feet wide, 38 feet long and 5
feet deep with 47 electrode pairs. (See Figure 9.)
D. The skimmer device will not be perfectly level but will have an
upward tilt of 6 inches per 100 lineal feet. This tilt will per-
mit the basin to operate with a skimmings blanket of at least 3
inches on the influent side. (See Figure 11.)
E. The first quartile of the basin will use 30% recycled dissolved
air for dewatering the skimmings. The dissolved air is introduced
perpendicular to the wastewater flow with six 1-inch tubes, three
on each side of the basin. The level at which the dissolved air
is introduced is exactly at the mid-section of the basin. (See
schematic 11.)
F. Four baffles with 50 percent free passage and with 2-1/2 inch
circular holes was used. This condition minimized channeling in
the electroflotation basin. A holding tank of approximately
100,000 gallons was used to equalize the flow. (See Figure 10.)
278
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SCHEMATIC-ELECTROCOAGULATION CELL
FIG. T
to
•vj
VO
-------
Figure 8. Dispersed air device.
Note the dispersed air device is placed just before the coagulation cell
(to the right).
-------
t-J
00
H
Figure 9. Electrode arrangement in basin.
Wiring is passed through a rubber pressure device.
-------
ho
Figure 10. View of electroflotation basin and baffels,
-------
MODIFIED LECTRO-THIC UNIT
Ni
00
SKIMMER ARM TRAJECTORY
DEIATERING REGION
WATER LINE
u 1
k
LT~— HOTZTT-.:
'-*.'•>/"*
v O ^
1 •* ^
! i
oc oo oo oo
f
oo co oo oo x"
V
— , —
— \ v3
I*
LECTRO CLEAR -BASIN
•v-> 00 ~3
PRESSURE
CELL
1 ,
J L
^ '
J
^
Figure 11. Schematic - electroflotation and dissolved air dewatering
in same basin.
-------
G. Automatic pH control was used. Dwell time in the pH adjustment
tank is 4 minutes. This chamber is also equipped with a mechani-
cal mixer. Both metal coagulant and sulfuric acid are added in
this chamber.
H. At the insistance of management, turbidity control was installed.
A Hach turbidity meter is used and, when turbidity is increased
above a predetermined value, the treated wastewater is recycled
to the holding tank for a second treatment.
I. The electroflotation basin contained 94 electrodes or 47 electrode
pairs. Approximately 1/2 of these electrodes were placed in the
first quartile of the basin. Their spacing was 3/8 inch apart
(surface to surface) and these were placed on polypropolene sad-
dles 12 inches from the basin bottom.
J. Finally, wastewater leaving the LectroClear treatment operation
was pH monitored on a recorder. This provides the needed records
for its discharge.
PERFORMANCE OF THE INSTALLED LECTROCLEAR-Z-M UNIT
Operating conditions of the wastewater treatment plant are as follows:
A. Electrocoagulation cell - 1500 amperes at 12.5 volts.
B. Electroflotation basin - 1400 amperes at 12.8 volts.
C. Dewatering unit employed 35 percent recycle at 55 psi gauge with
a retention time of 4 minutes in the pressure chamber.
D. Wastewater flow - 1.14 M^ (300 gallons) per minute, pH 4.5.
Analysis of wastewater leaving the LectroClear-Z-M unit is given
in Table 6. These analyses consist of 4-hour composites taken
on two consecutive days.
E. Chemicals added are:
1. 1200 mg/lt sulfuric acid 66° Be.
2. 100 mg/lt alum.
3. 6 mg/lt anionic polymer (X-400).
4. pH - 4.4 to 4.8.
Determination of solids content in the skimmings showed the following:
A. Lowest solids obtained - 13.7%.
B. Highest solids obtained - 17.5%.
Skimmings volume equaled between 4 and 7 volume percept of the wastewater
treated.
284
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TABLE 6. PERFORMANCE OF LECTROCLEAR-Z-M (pH 4.5) AT RENDERING PLANT
Treatment
Run 1
Influent
Effluent
Run 2
Influent
Effluent
Run 3
Influent
Effluent
Alum
mg/lt
100
100
100
H2S04
mg/lt
1200
1200
1200
Polymer
mg/lt
6
6
6
BOD
Total
mg/lt
7800
3850
6800
2200
8800
3400
BOD
Soluble
mg/lt
4800
3800
2100
2000
3500
3200
SS
mg/lt
4475
95
3200
110
2860
80
FOG
mg/lt
800
15
850
20
780
22
Protein*
mg/lt
1080
410
1100
385
990
340
* Nitrogen value x 6.25.
285
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DISCUSSION
The described plant was designed to provide effluent wastewaters with less
than 200 mg/1 of suspended solids and less than 100 mg/1 of hexane extract-
ables. The fact that the plant in reality produced results much better
than these is primarily attributed to the unique combination of a two-step
primary treatment combined with a dissolved air skimmings dewatering unit.
Based on the unusually good results obtained by this design, it follows
that the plant wastewater can be effectively treated by using only a tri-
valent metal coagulant or by using a combination of sulfuric acid and tri-
valent coagulant. The actual chemicals used will depend to some degree on
the objectives of the plant.
In summary, a new dimension has been established in the wastewater treatment
technology of rendering plants. This technology incorporates the following
three factors in one operation.
A. Operates in the close vicinity of the zero zeta potential by the
use of pH adjustment with sulfuric acid. This condition yields
skimmings which are more easily renderable.
B. The operation employes a sequential two-step technology (coagula-
tion cell plus flotation basin) where higher efficiencies are
achieved in the removal of fats and oils and suspended solids.
C. The technique of dewatering skimmings with the use of dissolved
air has the advantage of not requiring additional space, pro-
viding skimmings with a higher solids content and, lastly,
removing additional amounts of the suspended solids in the waste-
water as it passes through the dewatering section of the flotation
basin.
CONCLUSIONS
The conclusions are based on wastewater from a particular rendering plant.
Logic would say that they would apply to most rendering plants.
1. The average surface charge (streaming potential) on pollutants in the
rendering wastewater evaluated approaches zero at pH of about 4.2.
(See Figure 1.)
2. The combination of sulfuric acid, a trivalent metal cpagulant, and a
polymer provide for the most cost effective treatment. Due to the high
buffer action of the rendering wastewater at the plant in question,
unusually large amounts of sulfuric acid are needed. (See Figure 2.)
286
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3. From a practical sense, the problem of treating the wastewater to meet
predetermined effluent standards is just the beginning of the overall
wastewater treatment problem. Such factors as cost effectiveness, odor
caused by treatment, properties of the skimmings (renderability), and
disposal of the skimmings are all integral parts of the wastewater
treatment operation. The above are closely interwoven with correspond-
ing plant costs. More often than not, simply providing treated waste-
water with low suspended solids and fats and oil values will not
adequately satisfy overall plant environmental conditions.
4. The use of a two-step primary treatment using a coagulation cell is
especially effective in removing suspended solids and fatty materials
from rendering wastewater.
5. The use of a dissolved air dewatering operation in the flotation basin
itself is especially suitable and effective because it requires no
added space for the dewatering operation. It also lowers the suspended
solids in the effluent wastewater.
REFERENCES
1. Beck, E. C., Giannini, A. P., and Ramirez, E. R. Electrocoagulation
clarifies food wastewater. Food Technology, Vol. 28, No. 2, pp. 18-22,
1974.
2. Ramirez, E. R. Electrocoagulation clarifies food wastewater. Deeds &
Data, Water Pollution Control Federation, April 1975.
3. Ramirez, E. R. Dewatering skimmings and sludges with a Lectro-Thic
unit. Presented at WWEMA Industrial Pollution Conference, Chicago,
April 2, 1975.
4. Ramirez, E. R., Johnson, D. L., and Clemens, 0. A. Direct comparison
in physiochemical treatment of packinghouse wastewater between dis-
solved air and electroflotation. Delivered at 31st Annual Industrial
Waste Conference, Purdue University, West Lafayette, May 4-6, 1976.
5. Ramirez, E. R., Barber, L. K., and Clemens, 0. A. Primary physio-
chemical treatment of tannery wastewater using electrocoagulation.
Presented at 32nd Annual Industrial Waste Conference,-Purdue Univer-
sity, West Lafayette, 1977.
6. Ramirez, E. R., Johnson, D. L., and Elliott, T. E. Removal of sus-
pended solids and algae from aerobic lagoon effluent to meet proposed
1983 discharge standard to streams. Presented at 8th National Sympo-
sium on Food Processing Wastes, Seattle, March 31, 1977.
287
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PROTEIN RECOVERY FROM MEAT PACKING EFFLUENT
by
D. E. Hallmark*, J. C. Ward**, H. C. Isaksen***, W. Adams****
INTRODUCTION
This report describes the Sterling Colorado Beef Company Alwatech protein
recovery plant which is the first Alwatech recovery plant installed in
the United States.
The Alwatech process is used for the reclamation of high energy, high
quality protein concentrates from the fresh effluent wastewaters of fish,
meat, and poultry processing plants. Recovery of saleable protein materials
and simultaneous reduction by 60-90% of the pollution load (B.O.D.) of
plant wastewaters are the dual objectives of this process.
The Alwatech process uses lignosulfonic acid (LSA) precipitation and dis-
solved air flotation for recovery of the protein concentrate for an animal
food material. A 4% concentration of LSA as an energy source and/or pellet
aid is authorized in mixed feeds, liquid feeds, and flaked grains in many
countries (1) (2) (3). The Alwatech plant operation at Sterling Colorado
Beef Company is currently being optimized.
BACKGROUND
Historical Development
The basic research work leading up to the Alwatech process was started
in Oslo, Norway as early as 1960. At that time Leif Jantzen et. al. (3)
developed a method for separating pure high molecular weight ligposulfonate
(LSA) from sulphite liquor, and during studies of the properties of pure
LSA, the ability of LSA to precipiate soluble proteins from dilute aqueous
solutions was found to be a very promising application.
* Donald Sutherland Associates, Inc., Denver, Colorado
** Professor at Colorado State University, Fort Collins, Colorado
*** Alwatech A.S., Oslo 2, Norway
**** Sterling Colorado Beef Company, Sterling, Colorado
0 Data collection and evaluation of the Sterling Colorado Beef Company
Alwatech plant is being conducted under an EPA demonstration grant.
288
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Additional studies of the LSA precipitation of proteins resulted in a
patented method. On the basis of this patented method, Alwatech was
started in 1965 as a member of the Apothekernes Laboratorium for Special
Preparater A/S (AL Group of Companies) of Norway.
Alwatech developed an industrial process using LSA precipitation of pro-
teins for the treatment of wastewaters and recovery of proteins from abat-
toir, fish, and poultry plants.
Alwatech's early years of research and development were followed by the
installation of plants in many countries and industries. Alwatech operates
internationally, with subsidiaries and resident technical offices in a
number of countries, including the United Kingdom and the United States.
Dissolved Air Flotation
Dissolved air flotation (DAF) has performed well for many years in the
treatment of wastewaters. DAF is based on the fact that air is soluble in
water in direct proportion to the pressure applied. When the pressure is
released under the proper conditions, the air comes out of solution in the
form of tiny bubbles. If a pressurized solution of contaminants, water, and
air is agitated, and if the solution is released into an open vessel, the
bubbles and solids will combine and float to the surface due to their reduced
combined specific gravity. Then the float can be skimmed off of the
surface.
Before DAF could be used productively by industries with high protein
wastes, it was necessary to develop a means by which nutrients could be
recovered from wastewaters at a low cost, biochemical oxygen demand (BOD)
could be reduced, and dilute fats could be cheaply separated. Researchers
have reported on a variety of chemicals that can be added immediately pre-
ceding the DAF process to achieve some or all of the above objectives.
Barnett and Nelson (4) and D. B. Ertz et. al. (5) studied the effects of
adding Al2(S04), and Ca(OH)2, to the wastewater produced in the seafood
processing industry. However, the above authors were solely concerned
with meeting water quality standards and not with recovering an animal
food product.
Wayne A. Bough et. al. (6), on the other hand, reported on a chemical which
potentially could satisfy all the objectives. In their paper, the authors
demonstrated the efficacy of chitosan, (an organic polymer composed of
glucosamine residues) in producing a nutritious animal feed from wastewater.
Although chitosan would appear to satisfy the needs of a number of indus-
tries with protein rich wastewaters, FDA approval is pending.
Thus, at the present time, the only chemical additive that can economically
recover nutrients from effluent is lignosulfonic acid. This use of LSA
was developed by Alwatech A/S, of Norway, and is marketed under the trade
name of Alprecin in Europe. Because the Sterling Colorado Beef Company
is the first company in the United State to incorporate the Alwatech
process, the following discussion is particularly relevant for U.S. firms.
289
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GENERAL DESCRIPTION OF THE ALWATECH PROCESS USING ALPRECIN
The Alwatech process is a unique patented system for the recovery of a
dry saleable meal from abattoir, poultry packing, and fish processing
wastewaters. The process also treats these wastewaters to the point where
they can be discharged into municipal sewers.
The Alwatech process is based upon the specific precipitation of proteins
(7) by purified high molecular weight lignosulphonates (ALPRECIN), under
acid conditions. Lignosulphonates are chosen because, unlike alternative
chemicals, they can precipitate dissolved blood, and they are accepted
as animal feed additives by both the European Economic Community and the
Federal Drug Administration.
The high molecular weight lignosulphonate is derived from sulphite lye,
a by-product of wood pulping, from which the major part of the carbohy-
drates, in themselves a source of pollution, has been removed.
The process wastewater from abattoirs, poultry packing plants, and fish
processing industries exhibits a varying flowrate and will contain large
amounts of suspended solids in addition to dissolved and emulsified fat
and proteins. It is recommended that screening and a balancing tank be
used to reduce surges in flow and quality.
To obtain the maximum benefit of the protein recovery and effluent treat-
ment ability of the Alwatech process, it is sometimes advantageous to let
some particular streams from a slaughterhouse undergo separate pre-treat-
ment or by-pass the Alwatech plant altogether. Examples of^ the first kind
is tripe wastewater and of the latter cattle pen wastewaters. Minimum
balancing capacity is normally equal to 1/2 to 1 hour flow, depending on
the production rate at the site. If a larger balancing capacity is installed,
however, the plant operating hours may be extended up to 24 hours per day.
After screening, the equalized flow of wastewater is precipitated with puri-
fied high molecular weight lignosulfonic acid at a pH of approximately 3,
the pH being reduced with sulphuric acid. Before the treated effluent
is discharged into the sewer, or a subsequent biological treatment system,
it is neutralized to a pH between 6 and 8 with calcium hydroxide or
another base such as sodium hydroxide.
Following precipitation, the floe, which contains protein, fat, and sus-
pended matter, is separated by dissolved air flotation.
From a typical wastewater with a BOD of 1,000 to 2,500 mg/1 before any
treatment, the Alwatech process normally produces an effluent of the
following quality:
BOD 70 - 80% reduction
Suspended Solids less than 300 mg/1
Fat less than 75 mg/1
290
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The concentration of the sludge as removed from the flotation system is
normally 6 - 12% solids depending largely on the origin and pre-treatment
of the process wastewater.
The sludge removed from the flotation tanks is neutralized with calcium
hydroxide. At the same time, surplus or diluted blood may be added.
After neutralization, with or without blood, the sludge is processed through
a coagulator to a filter belt for dewatering. A decanter (centrifuge)
may also be used for dewatering.
The sludge will contain 30-50% solids after dewatering depending on the
dewatering system used.
The water removed from the sludge in the dewatering process may contain
up to 40% of the original lignosulphonate added in the chemical treatment
process. In large installations, a lignosulphonate recirculation system
is installed to reduce chemical consumption.
The concentrated (30-50% solids) sludge may be dried in a rendering plant,
mixed with other by-products, or dried in a separate drier.
THEORY OF PRECIPITATION WITH LIGNOSULPHONIC ACID (LSA)
The theory of LSA precipitation was reported by T. R. Foltz, et. al's (7),
and is quoted below:
"The precipitation of soluble protein with soluble lignosulphonic acid
in an acidic aqueous system is believed to be a nearly instantaneous
reaction involving the negatively charged sulphonate groups on LSA
molecules and positively charged amine groups present on the protein
molecules. The complexing of these large molecules results in a
gelatinous suspended material that can be removed by a suitable physical
liquids-solids separation technique.
"Protein molecules contain both positively charged amine groups and
negatively charged carboxyl groups when the solution is at pH values
near 7. Acidification of proteinaceous waste water to pH values below
the isoelectric point will result in proteins carrying a net positive
charge. Isoelectric values vary with different proteins, but acidifica-
tion to 3.5 or below normally insures a pH below the isoelectric for most
protein solutions.
"Lignosulphonic acid when in solution has the sulphate group essentially
completely ionized, resulting in a net negative charge on the LSA
molecule. With acidification, the strong acid group of the sulphonate
continues to carry a negative charge even at pH values of 2 to 3. At
extremely low pH values below 1, the sulphonate group begins losing its
charge."
"Table I summarizes the respective net charges on LSA and protein mole-
cules at various pH ranges, noting the resulting precipitation potential.
291
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Table 1
INFLUENCE OF pH ON LSA - PROTEIN PRECIPITATION.
pH Range
0-1
2-3
3.5 - 4.5
Above 4.5
Protein
Positive Charge
Positive Charge
Isoelectric
(no net charge)
Negative Charge
LSA
Weak Negative Charge
Negative Charge
Negative Charge
Negative Charge
Precipitation
Poor
Good
Poor
None
"This table reveals that the pH must be in range of 2-3 to obtain
effective precipitation. Actual experimental evidence confirms that this
is the optimal pH range for precipitation of the maximum amount of
protein.
"Because the precipitation involves balancing of opposite ionic charges,
it follows that an optimal ratio exists between LSA and proteins in order
to maximize protein removal with the least amount of LSA. Experimental
evidence also confirms that treament of proteinaceous wastes with LSA
is quantitative, making LSA dose control important.
"In precipitating and removing the LSA and protein complex, fat and fatty
material (as determined by hexane soluble extraction) are also largely
removed. In raw waste, fat is primarily particulate and emulsified matter
with a free fatty acid content ranging from 5 to 50 per cent of the total
fat content. Acidification of raw wastes eliminates the strong negative
charge on the free acid carboxyl groups resulting in a loss of water
solubility. Therefore, at protein precipitating pH values, most of the
fat material tends to separate from the water and float to the surface.
The presence of LSA would not be expected to enhance fat removal if
protein matter was absent from the raw wastes.
"With protein present and forming an insoluble material with LSA, the
fat tends to be comingled with the protein LSA material."
THE USE OF ALWATECH RECOVERED PROTEIN CONCENTRATE AS ANIMAL FEED
The Alwatech Protein Concentrates
The composition of these protein concentrates is dependent primarily on
the sources of the raw material and the components of the effluent treated.
From fish and meat sources which have been the most investigated and uti-
lized to date, high quality components are assured because the material
is dominantly muscle, blood, and fat.
Flesh particles, dissolved blood, and released fat are treated within ap-
proximately 1-2 hours at pH 3 so that the freshness and bacteriological
condition of the raw material is excellent and superior to many other by-
product animal foodstuffs.
292
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The LSA concentration in the dry matter of the protein concentrates may
vary from 5 - 15% but is normally about 10%. The following tables show
typical analyses of Alwatech protein concentrates recovered from waste-
waters in the fish and meat industry.
An illustrative average analysis of the Alwatech herring protein concen-
trate is comparable with commercial herring meal with due allowance for the
LSA content (Table 2).
Table 2 COMPARISON OF RECOVERED PROTEIN WITH HERRING MEAL.
Alwatech herring
Commercial protein
herring meal,% concentrate, %
Crude protein (organic nitrogen x 6.25)
Fat
Calcium
Phosphorus
Sodium
LSA
69
8
4.8
2.8
1.4
0
71
9
4.7
2.8
1.6
10
Table 3 ANALYSIS OF A SAMPLE OF MATERIAL RECOVERED BY THE ALWATECH PROCESS
AT KBS. SWEDEN (PRIMARILY PORK SLAUGHTERING).
%
Protein - 56.0
Oil - 15.0
Fiber - 2.5
Nitrogen Free Extracts - 20.0
Ash - 6.4
The amino-acid composition of the protein in Alwatech protein concentrate
meals has been determined for products obtained from fish and blood processing
(1). It may be seen from Table 4, that the composition is unaffected by the
LSA treatment. This would be the expected result from conventional acid
precipitation of proteins extensively studied including fish, egg, soya,
groundnut, and casein whose amino-acid composition is altered only by virtue
of loss of certain components in the mother liquor, (i.e. non-precipitated
fraction) and not by precipitation as such.
293
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Table 4
AMINO-ACID COMPOSITION OF PERCENTAGE CRUDE PROTEIN.
Fish
Untreated
LSA
Precipitated
Blood
Untreated
LSA
Precipitated
Cystine
Aspartic acid
Methionine
Threonine
Serine
Glutamatic acid
Glycine
Alanine
Valine
Isoleucine
Leucine
Tyrocine
Phenylanine
Lysine
Histidine
Arginine
1.0
9.0
3.2
4.6
4.1
14.1
5.6
6.3
5.6
4.7
6.9
2.1
3.6
7.3
2.2
5.0
1.1
9.0
3.4
4.7
4.0
14.5
5.5
6.2
5.1
4.4
6.6
2.2
3.8
7.2
2.2
5.3
0.9
9.4
2.9
4.6
4.5
13.6
7.4
6.7
5.0
4.7
7.3
2.9
4.0
8.2
2.4
6.0
0.9
8.7
2.9
4.4
4.2
13.2
7.3
6.5
4.9
4.3
7.3
2.3
3.9
7.8
2.2
6.0
The digestible protein determined by the pepsin-hydrochloric acid method
showed that the feed value of proteins precipitated with lignosulphonates
is only 15-20% lower than for equivalent unprecipitated blood meal. This
must be considered as an unexpected good result because it is known from the
works of B. Naess (8) that lignosulphonates have an inhibiting effect on
pepsin under acid conditions.
In the trypsin system, however, there is no such inhibiting effect, and to
determine the complete feed value it is necessary to include the Trypsin
method. Moreover, it was found that protein precipitated by ordinary
sulphite lye had a lower feed value than protein precipitated by Alprecin.
PROTEIN QUALITY AND FEEDING TRIALS
LSA is a purified derivative from wood pulping liquors which has been
fed extensively to many animal species for many years in dried form.
Extensive tests under controlled conditions reported in 1973 (9) show that
relatively high levels of sulphite liquor concentrates in animal feed
does not affect feed conversion.
The harmless nature of LSA in rat and poultry feeds has been borne out in
feeding tests of protozoa, rats, and chickens to determine the protein
quality and feeding value of Alwatech protein concentrates. Up to 4%
of crude LSA as an energy source and/or pellet binder is authorized in
mixed (compound) feeds, liquid feeds, and flaked grains in many countries
with a wide range of feeding practices and ration formulations (2).
The products contain 60% lignosulphonate, which implies a safe level in
294
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feed stuffs of 2.5% LSA or less. This is above the anticipated inclu-
sion rate in feeds from Alwatech protein concentrates of which a relatively
small tonnage would be available, compared with the quantity of other
protein and energy ingredients in farm animal diets.
Provided normal and conventional practices in the drying of protein pro-
ducts from industrial processes are followed, protein quality should be
equivalent to that of the starting material. Indeed blood proteins, fish
solubles or by-product fats, for example, probably receive longer and pos-
sibly more severe drying conditions than Alwatech protein concentrates.
In the abattoirs and meat packing industry, the recovered material can be
added to renderable material for production of meat-bone meal and techni-
cal fat, or dried separately. A number of feeding trials with Alwatech
recovered protein concentrates show that the feeding values of the recovered
material are comparable with existing market qualities and that substi-
tution of up to 50% in fish meal or soya bean meal feed mixture with Alwa-
tech protein concentrate (APC) does not affect live-weight gain, feed con-
version ratio, or mortality.
Poultry feeding trials have been carried out as chicken growth tests (10),
poultry screening tests and pelleted feed tests.
Table 5 shows a typical result obtained by three groups of 510 chicks
on a diet containing 22% crude protein where the APC content is substi-
tuted for herring and soyabean meal.
Table 5RESULTS OF CHICK FEEDING TRIALS.
Herring APC APC
4% 4% 8%
Mortality
0-7 days 35 22 34
8-49 days 13 68
Live-weight gain
50 days (g) 1270 1290 1311
Feed conversion ratio 2.13 2.10 2.05
Pig feeding trials have been conducted with addition of LSA in amounts of
3% and 12% of the feed (11) with the Alwatech protein concentrates sub-
stituted for parts of or all of the soyabean meal in the diet. These
pig feeding trials show that the LSA content in feed can be up to 6%
and that 50% of the soyabean meal can be replaced by Alwatech protein
concentrate without any significant effect on live-weight gain, feed con-
version, or mortality.
295
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DESCRIPTION OF THE ALWATECH PROCESS INSTALLED AT STERLING
COLORADO BEEF COMPANY (SCB)
Plant Capacity
This effluent protein recovery system has been designed to treat up to
3,000 cubic meters per day (800,000 gpd) of wastewater containing 4,100
kilograms (9,000 pounds) of BOD5 and 5,400 kilograms (12,000 pounds) of
suspended solids over 16 hours. At this BOD5 loading, the nominal capa-
city of the effluent treatment plant is 200 cubic meters per hour (52,000
gph).
Table 6 shows the current loading at the balancing tank of the Sterling
Colorado Beef Company packing plant. The test data presented are based
on 4-hour composite samples.
Table 6. CURRENT WASTEWATER CHARACTERISTICS AT SCB.
BOD5, mg/1
COD, mg/1
Suspended Solids, mg/1
Oil and Grease, mg/1
Flow, gpd
Beef processed, head/day
Average live weight, pounds
Minimum
1,500
2,200
740
320
Average
2,274
3,572
1,825
1,140
513,500*
1,750
1,031
Maximum
4,900
6,320
2,650
4,040
* This flow rate is the average treated through the Alwatech plant during
preliminary testing and does not reflect the total water used at
Sterling Colorado Beef Company.
The plant has been designed to remove 70% of the applied BOD load, reduce
the suspended solids to less than 300 mg/1, and reduce oil and grease to
less than 75 mg/1.
It is estimated that the plant will recover approximately 4,500 kilograms
(10,000 pounds) of dry solids per day from dewatered sludge containing
60 - 70% moisture. The dewatered sludge has less than 10% fat on a dry
weight basis. Tests have demonstrated that it can be dried in the existing
rendering plant. It is possible that a separate drier could be used for
the recovered product. The plant layout is shown in Figure 1, and Photo 1
shows the building that contains the Alwatech plant.
296
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FIGURE I - STERLING COLORADO BEEF COMPANY
ALWATECH PLANT LAYOUT
-------
Photo #1 - Alwatech building at Sterling Colorado Beef Company,
Sterling, Colorado.
Wastewater Pre-Treatment
SCB has approximately 1,500 cubic meters per day (400,000 gpd) of process
wastewater from the slaughtering operations with a BOD5 of 1,600 to 1,800
mg/1 after screening. The wastewater is screened through a rotating
screen at the rate of 120 cubic meters per hour (30,000 gph) before being
discharged to a 300 cubic meter (80,000 gallon) circular clarifier equipped
with a bottom scraper. The clarifier has provisions for removal of float-
ing fat (grease). Solids removed by the screen and from the surface of
the clarifier are returned to rendering.
The clarifier, which was present prior to installation of the Alwatech
plant, is now used as a combined clarifier and balancing tank. During
the day the level in the clarifier is kept 15 to 30 cm below the overflow
weir for grease removal while it is pumped 2.5 m (8 feet) down each even-
ing. The night wastewater from the slaughterhouse is allowed to fill up
the clarifier again overnight. Solids settled out in the clarifier are
removed at regular intervals for recovery or deposited off site.
Approximately 65 cubic meters per day (17,000 gpd) of highly polluted
effluent with a pH between 11 and 12 is discharged from the tripe washing
department. This effluent is screened on a rotating screen before being
discharged to the clarifier. Alternatively, the screened wastewater may
be pumped to the Alwatech plant bypassing the clarifier. Solids removed
by the screening operation are returned for rendering.
Blood coagulation is done in-line with live steam. Coagulated blood is
separated on a shaker screen. The effluent originating from the dewatering
of blood has a very high BOD and contains valuable suspended solids.
This effluent is pumped to a settling tank and thereafter pumped directly
298
-------
to the Alwatech plant bypassing the clarifier.
to the Alwatech sludge dewatering system.
Settled solids are pumped
Sterling Colorado Beef Company has direct contact condensers in the ren-
dering plant which discharge approximately 750 cubic meters per day
(200,000 gpd) of condenser water at a temperature of 80°C (175°F). This
particular wastewater contains very little fat or proteins for recovery
in the Alwatech effluent treatment system. It has a BOD generally below
the BOD level discharged from the Alwatech plant. Tentative plans are to
discharge this effluent to the sewer.
Cattle pen wash water is screened on a shaker screen and discharged to
two settling tanks in series. At present this wastewater bypasses the
Alwatech system. SCB has approximately 70 cubic meters per day (18,000
gpd) of cattle pen wash water and after screening and settling it contains
approximately 2,400 mg/1 BOD.
All effluents from preparation of hides are discharged separately and are
not treated in the Alwatech plant.
It is desirable to bypass the clarifier (balancing tank) with particular
waste streams such as those from tripe operations and cattle pens, to reduce
biological action in this tank. Biological activity in this tank has been
found to reduce the protein content of the final product.
Photo #2 - DAF tanks being installed at SCB.
299
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Alwatech Process Flow Description
Figure 2 is the Alwatech process flow diagram of the Sterling Colorado
Beef Plant. The incoming wastewater is pumped by feed pumps M3 and M4
from the clarifier to flotation tanks I and II (See Photo 2). Before this
wastewater enters the flotation tanks, LSA, H2S04, and water (partly satu-
rated with air) are added. LSA, which is delivered as a powder, is dis-
solved in water to a concentration of 10 to 15%. A dosing pump M6, ad-
justable from the control panel, delivers the needed quantity of LSA solu-
tion. H2S04 is taken directly from a storage tank and diluted with waste-
water before being added to the 2 flotation tanks. The H2SC>4 is pumped
by dosing pump M5 which is automatically controlled by the pH I equipment
which utilizes electrodes that are cleaned ultrasonically.
Water, partly saturated with air, is produced from a mixture of water and
wastewater by means of high pressure pumps Ml and M2, injectors, and pres-
sure vessels I and II (See Photo 3). The treated effluent is neutralized
with Ca(OH)2 and is dosed by the neutralization dosing screw M19 (in the
Lime Silo) which is controlled by pH II equipment (See Photo 4).
The protein sludge is removed from the surface of the 2 flotation tanks
and pumped by flotation pumps M10 and M13 to the 3 sludge treatment tanks.
Bottom sludge is removed from Flotation Tanks I and II by bottom scrapers
M16 and M17, respectively, and pumped to the 3 sludge treatment tanks by
bottom sludge pump M18. Sludge pumps M29 and M30 pump the protein sludge
to heat coagulators I (M31) and II (M32), respectively (See Photo 5).
Dewatering on Filterbelts I (M33) and II (M34) produces a combination
protein fat concentrate containing approximately 40% dry matter (See Photo 6)
Reject pumps M35 and M36 pump the liquid from the 2 filter belts to the
flotation tanks influent line. The Alwatech process is controlled from a
central panel containing the automatic equipment (See Photo 7).
Sludge on the bottom of the clarifier is pumped to the settling tank by
sludge pump M37. Sludge pump M38 moves this concentrated sludge to the
3 sludge treatment tanks.
300
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COLORADO BEEF COMPANY
ALWATECH PROCESS CONTROL BOARD
Co
O
-------
Photo #3 - Air Injection Pressure Chambers at SCB,
Photo #4 - Lime Neutralization Tank at SCB.
302
-------
Photo #5 - Coagulators and Filter Belts for Sludge Drying at SCB.
Photo #6 - Sludge Tanks and Filter Belts at SCB.
303
-------
Photo #7 - Electrical Control Center for the Alwatech Process,
304
-------
REFERENCES
1. G. D. Rosen, Safety and Quality Considerations on Protein Concentrates
Manufactured by the Alwatech Process, unpublished report.
2. American Paper Institute, 1958 Food Additives Amendment, Release 14,
May 16, 1970, Regulation No. Sec. 121.234, Fed. Doc. 70-6436, Filed
1970.
3. Jantzen, L., "Protein-Rich Feed Material and Method of Making," U.S.
Patent No. 3,390,000 (July 2, 1968).
4. Barnett, H. J. and Nelson, R. W., "A Preliminary Report on Studies
to Develop Alternative Methods of Removing Pollutants from Tuna Pro-
cess Wastewaters," Proceedings of the Sixth National Symposium on Food
Processing Wastes. EPA-600/2-76-224 (1976).
5. Ertz, D. B., Atwell, J. S., and Forscht, E. H., "Dissolved Air Flota-
tion Treatment of Seafood Processing Wastes — An Assessment," Pro-
ceedings Eighth National Symposium on Food Processing Wastes. EPA-
600/2-77-184 (1977).
6. Bough, W. A., Landes, D. R., Miller L., Young, C. T., and McWhorter,
T. R., "Utilization of Chitosan for Recovery of Coagulated By-Products
from Food Processing Wastes and Treatment Systems," Proceedings of
the Sixth National Symposium on Food Processing Wastes, EPA-600/2-76-
224 (1976).
7. Foltz, R. R. Jr., Ries, K. M., and Lee, J. W. Jr., "Removal of Protein
and Fat from Meat Slaughtering and Packing Wastes Using Lignosulfonic
Acid," Proceedings Fifth National Symposium on Food Processing Wastes,
EPA 660/2-74-058 (1974).
8. Naess, B., Westbye, 0., Hildrum, K. I. and Nafstad, I., "The Effects
of Peptide-Precipitating Lignosulphonic Acids on the Proteolytic
Activity of Pepsin In Vitro, and on the Response of Pigs to an Ulcer
Inducing Diet," Effects of Sulphite Spent Liquor Components on Some
Biological Systems, Universitetsforlaget, Oslo, 1972.
9. Klopfenstein, T., Koors, W., Farlin, S., Nebraska Beef Cattle Report,
1973.
10. Herstad, 0. and Hvidsten, H., Protein Recovered from Industrial Waste
Water as Feed for Chicks, Department of Poultry and Animal Science,
Agricultural University of Norway, AS-NLA, Norway.
11. Naess, B. and Fjolstad, M., "The Effect of Feeding Peptide Precipi-
tating Lignosulphonic Acids in Various Concentrations to Growing Pigs,"
Effects of Sulphite Spent Liquor Components on Some Biological Systems,
Universitetsforlaget, Oslo, 1972.
305
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A METHOD OF PHYSICO-CHEMICAL TREATMENT
OF ORGANIC WASTEWATERS
by
P. Stephenson*
ABSTRACT
A process to treat organic wastewaters containing significant concentrations
of protein and grease is described. Special reference is directed toward
the treatment of meat packing plant effluent as it is for this application
the majority of process data is available. Development is traced from
initial effluent characterisation and experimentation, through pilot plant
trials to preliminary full scale evaluation. Particular importance is
attributed to the recovery of useful by-products and their application as a
feed supplement for non-ruminant animals. In one instance treatment of a
meat packing plant effluent, as discharged after primary treatment in a
saveall or catch basin, resulted in 75-80% removal of chemical oxygen demand.
Broiler grower chicken feeding trials using the by-product recovered from
this treatment showed comparable growth to similar inclusions (0-14%) of
conventional Meat and Bone meal supplements.
INTRODUCTION
The high organic content of many industrial wastewaters, especially those of
the food processing industries, results in a considerable biochemical oxygen
loading to effluent treatment plants and natural waterways. In the meat
industry protein and grease bearing effluents, even after primary treatment
to remove the bulk of floatable and settleable solids, are typically an
order of magnitude stronger (based on 8005) than domestic wastewater.
For a typical New Zealand meat packing plant with an average wastewater flow
of 6750 m^/d (1.76 mgd (U.S.)) and, mean total organics concentration, after
the removal of bulk solids in a saveall or catch basin, of 1800 mg/1 the
daily organic solids discharge would amount to approx. 12,150 kg/d. The
significance of a suitable method of treatment and the potential for
by-product recovery is therefore apparent.
*Morrison, Cooper and Partners, Ghuznee St., Wellington, New Zealand.
Currently at Graduate School, McMaster University, Hamilton, Ontario,
Canada.
306
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The Application of Physico-Chemical Processes
An intelligent approach to the selection of any treatment process initially
involves characterisation of the wastewater over a significant time period
and an assessment of the degree of treatment required for that particular
plant location. Previous applications have involved partial treatment of
sewage effluent by lime precipitation and acid cracking of wool scour effluent.
In general physico-chemical treatment systems are considered expensive in
comparison with many biological treatment processes such as anaerobic
lagoons. However when physico-chemical treatment permits the recovery of a
valuable by-product and or water for reuse the project economics may be
more favourable. This is especially so in urban localities where water and
sewage charges are applicable and available land for the treatment plant is
limited. Additional advantages include the adaptability of some systems
to input effluent composition fluctuations and toxic environments, both of
which significantly affect biological process performance.
Background to the Process Development
Initial studies in 1968-69 at the N.Z. Department of Scientific and Industrial
Research on the application of regenerated cellulose based ion exchange resins
for the removal of proteins and charged organic groups "from meat packing plant
effluents indicated that a pretreatment to remove high levels of grease and
suspended solids was necessary to prevent resin fouling. It was also
considered desirable to reduce the protein concentration to levels more
attune to practical separation by ion exchange (max. 300-400 mg/1 protein).
The pretreatment performance required was beyond that achievable by any form
of mechanical screening, and biological processes affected a complete change
in effluent composition. Thus a number of chemical treatment processes were
investigated to remove the majority of effluent organics and produce an
effluent more amenable to ion exchange.
Extensive trials, both laboratory and pilot scale, since 1968 have progressed
to the stage where a reliable and efficient chemical treatment has been
developed for large scale application. It is this process which is discussed
in this paper. Throughout its development emphasis has been placed on a
process which incorporates:
1. Reliability to input effluent composition and solids loading
fluctuations.
2. A sludge with good dewatering characteristics.
3. A maximum possible reduction in biological oxygen demand (BODs).
4. The production of valuable by-products and water for reuse.
The chosen process in reality represents a compromise of these features.
Its application to effluents from other food processing industries such as
fish and poultry has been successful and current investigations involve
the examination of its use in the treatment of a widespread range of organic
bearing industrial effluents, especially those with high concentrations of
protein and grease where by-product recovery is most likely.
307
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PROCESS DESCRIPTION
In essence a chemical coagulation process is employed to remove a major
fraction of the organics and suspended material remaining after primary
treatment. The process involves a double pH shift with the addition of
chemicals, resulting in the formation of a flocculated mass which is readily
recovered and contains the majority of organics from the effluent.
The treatment process is sequentially summarised as follows:
1. Sulphuric acid addition to denature protein. The reaction proceeds in
a stirred tank maintained at a controlled pH corresponding to the
isoelectric point of the solution.
2. Coagulant addition to the acidified effluent. The particular material
selected will depend upon the process performance required and the
proposed end use of the byproduct. In the treatment of meat packing
plant wastes a phosphate coagulant is added in the form of crushed
superphosphate.
3. Neutralisation. Stagewise addition of a lime slurry raises the pH and
promotes further coagulation. The final stage is controlled at the
optimum pH for flocculation.
4. A dilute flocculant solution is then added to the coagulated effluent
and is dispersed under controlled hydraulic conditions.
5. The effluent is gently agitated in the flocculation chamber of a
flocculator-clarifier to promote the growth of large, readily settleable
floes. Separation of these in the clarifier section then produces an
effluent substantially free of suspended solids.
6. The settled solids are thickened, heated, centrifuged and pneumatically
dried. Centrate is recycled to the untreated wastewater inflow stream.
The optimal chemical dose rates and retention times at the various stages
of treatment are a function of the waste composition, treatment requirements,
and engineering advantages. For a particular application these parameters
are determined on the basis of laboratory and pilot plant studies. By way
of example the most utilised scheme, and that employed to treat meat packing
plant wastes, is detailed in Figure 1.
TREATED EFFLUENT QUALITY
Process performance is a function of the untreated effluent characteristics.
Providing an effluent contains significant concentrations of grease and
protein a reduction in Chemical Oxygen Demand (COD) of 75-80% may be expected
for the coagulation process alone. In general an increase in solids loading
and influent' strength has resulted in improved removal efficiencies and
greater by-product recovery, thus reducing fluctuations in treated effluent
quality. Almost complete removal of grease and suspended solids has been
achieved for the treatment of many effluents and Kjeldahl nitrogen reductions
in excess of 50% are typical.
308
-------
u>
o
VO
SCHEft
MEAT
IATIC PROCESS FLOW DIAI
PACKING PLANT EFFLUEN
~~* Decapol A33 Flocculant
1 Hydrated Lime to PH 9.0
1 Superphosphate ( 200 mg/l)
1 Sulphuric Acid
! to pH 3.0
1
Plant
— *] Effluent
Cent rate
Recycle
HEAT
RECOV
, Direct Steam
ACIDIFICATION NEUTRALIZATION
dOmin) (5min)
Sludge Flow
|
\ fc . ' fc
^"""•^1 •^— ^
t ' >
COAGULATION DECANTER
fERY (105°C) CENTRIFUGE
Injection ^
1 -
Fi
SRAM FOR CHEMICAL TREATMENT OF
T (as discharged from a Saveall )
PrrvaftB ^antion timo. tamponitiir««
and chemical dose rates are based on
Laboratory and Pilot Plant studies at 8
major meat packing plants in
New Zealand.
Treated
Effluent ^_
fc ^ * , fc
oU ^:^^
FLOCCULATION SEDIMENTATION
(Smin) (overflow rate
2.45m3/m2hr)
~\ ^ Q-+ *~
/' V
.HT1!/ I Dried
W-T 1 By-product f-
RING Air W—
DRYER CYCLONE
gure 1
-------
In Table 1 the process performance is summarised for the treatment of
protein and grease bearing wastes typical of New Zealand Meat Packing Plants,
The figures tabulated are based on data recorded over a 4 year period of
pilot plant and laboratory testing on site at 5 meat packing plants.
Shown in Table 2 is the composition of the by-product recovered after
treatment of the effluents described in Table 1.
TABLE 2. COMPOSITION OF THE BY-PRODUCT RECOVERED FROM THE
CHEMICALLY TREATED EFFLUENTS DESCRIBED IN TABLE 1
By-Product Mean „
TT -• j. Range
Component Value*
By-Product Total Solids 1685 1200-2270
Recovery (mg/1)
Ash Content (%) 25 23-30
Total Grease (%) 27 15-35
Protein as NX6.25 (%) 31 25-39
Other Organics (%) 17 12-23
Composition as evaluated on a dry wt. basis.
CHEMICALS AND UTILITIES
Chemical Treatment
Fluctuations in effluent composition, buffering capacity, and solids loading
are common and result in variable acid and lime demand. Coagulant and
flocculant dose rates may be constant and apportioned according to flow.
Typical treatment costs (April 1976) on a chemical usage alone basis are
shown in Table 3 for a meat packing plant wastewater as discharged from a
saveall system used to remove bulk solids. Figures 2 and 3 illustrate the
variability of acid and lime demand for the treatment of meat packing plant
effluent from the five plants with wastewater characteristics as described
in Table 1.
Utilities
Treatment plant power requirements vary with flow and composition, as these
effect the specific capacity of equipment. However in the case of a meat
packing plant with a nominal effluent flow, from a saveall system, of
4500 m-Vd charges (April 1976) for labour, electricity, oil, and steam will
amount to approx. 5.8C (N.Z.)/m3 (22.0C/1000 U.S. gal.). The basis for this
cost is shown in Table 4.
310
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TABLE 1. PROCESS PERFORMANCE FOR THE CHEMICAL TREATMENT OF PROTEIN AND GREASE BEARING EFFLUENTS
AFTER PRIMARY TREATMENT AT MEAT PACKING PLANTS IN NEW ZEALAND*
Effluent**
Component
Chemical Oxygen Demand (mg/1)
Total Solids (mg/1)
Suspended Solids (mg/1)
Total Organics (mg/1)
Ash Content (mg/1)
Total Grease (mg/1)
Protein as NX6.25 (mg/1)
PH
Untreated
Effluent
Mean Range
2765
2525
1235
1705
820
550
795
7.5
1570-3855
1960-4120
890-1960
1460-2010
250-2105
400-690
490-1170
7.1-8.8
Treated
Effluent
Mean Range
535
1855
60
700
1155
20
370
' 9.0
265-750
1305-3380
35-115
455-910
420-2470
15-30
225-560
9.0
y
/o
Reduction
Mean Range
81
27
95
60
+41
96
53
76-83
18-35
91-97
45-71
+17-+105
94-99
49-59
* The Table records data from extensive laboratory and pilot plant studies at five different meat
packing plants.
** All analyses as outlined in Standard Methods (2).
-------
TABLE 3. TYPICAL CHEMICAL COSTS* FOR THE TREATMENT OF A
MEAT PACKING PLANT WASTEWATER AS DISCHARGED FROM
A SAVEALL SYSTEM
Chemical
Sulphuric Acid (98%)
Hydrated Lime
Phosphate Coagulant
Flocculant
Mean
Concentration
(g/n»3)
275
385
200
2
Total
Unit
Cost
($/ tonne)
73.
50.
30.
3250.
Chemical Cost ($/m3)
C$/1000 U.S. gals)
Treatment
Cost
($/m3)
0.020
0.019
0.006
0.007
0.052
0.20
*Chemical cost in New Zealand as at April 1976.
TABLE 4. TYPICAL UTILITY CHARGES* FOR THE TREATMENT OF A
MEAT PACKING PLANT WASTEWATER (4500 m3/day) AS
DISCHARGED FROM A SAVEALL SYSTEM
Utility
Labour
Oil
Steam
Electricity
Approx. Usage
per m3 of Effluent
Treated
$ 3.00/hr
$ 110/tonne
$ 9.20/1000 kg
$0.021/kWH
Total Cost ($/m3)
($/1000 U.S. gal)
Treatment
Cost
($/m3)
0.015
0.027
0.009
0.007
0.058
0.22
*Typical utility charges in New Zealand as at April 1976.
BY-PRODUCT RECOVERY
The recovery and handling of solids is an important feature of any waste
water treatment scheme as in the majority of processes 40-60% of the capital
312
-------
ACID DEMAND TO ACIDIFY UNTREATED MEAT RACKING
PLANT EFFLUENT TO pH 3.0 AS A FUNCTION OF C.O.D.
\4000
O)
I 3000
H—
«^
UJ
2000
(0
O
o 1000
d
s .
Figure 2
\ 4000
O)
3000
UJ
2000
1000
Q
8
Figured
Plant 1 ©
P5 ©
P2
P3
P4 ©
100 200 300 400 500
Sulphuric Acid Demand (mg/l)
LIME USAGE TO NEUTRALIZE ACIDIFIED EFFLUENT
TO pH 9.0 AS A FUNCTION OF C.O.D.
Plant 1 A
P2 A
P3 A
A P5
P4 A
100 200 300 400 500
Hydrated Lime Use (mg/l)
313
-------
investment is involved. This aspect is especially significant to a process
in which the recovered by-product is saleable and utilized to offset treatment
operating costs. For these reasons considerable emphasis in the overall
process development has been extended to evaluating a suitable method of
solids recovery and to the nutritional value of the product as an animal
feed.
Sludge Conditioning and Dewatering
The basic aim of sludge treatment is to reduce the volume and render the
sludge inoffensive for disposal or recovery as a by-product. Sludge
conditioning refers to chemical and physical methods for altering the sludge
properties to permit the release of water. In general organic sludges require
some form of conditioning prior to dewatering to transform the characteristic
amorphous gel-like structure into a porous mass which is more readily dewatered.
In this process heat treatment is employed to break down this gel-like
structure and permit dewatering without further chemical treatment. A change
in particle structure results due to the coagulation of proteins and the
release of a proportion of unbound grease.
Heat treatment is by direct steam injection. To reduce the steam requirement
the sludge is initially thickened and preheated in a heat exchanger, using
hot water from the dewatering stage to recover most of the sensible heat.
The coagulated sludge is then partially dewatered in a horizontal bowl
decanting centrifuge with continuous solids discharge. The bowl and conveyor
speeds, and the pond depth are chosen so as to optimize solids recovery and
cake moisture content.
The composition of effluent to be treated will determine the percentage of
free fat present in the sludge. When heated a proportion of this fat may be
rendered and leave the centrifuge in the liquid phase. If sufficient
quantities are present economic recovery may be justified before the centrate
is recycled.
For by-product recovery the discharged centrifuge solids are pneumatically
dried to approximately 92-93% solids. A short residence time in the pneumatic
dryer ensures minimum thermal degradation of the product.
By way of example the pilot scale dewatering of a sludge recovered after
treatment of a meat packing plant effluent by this process is discussed:-
Thickened sludge recovered after sedimentation was heat coagulated at
103-105°C for approx. 1 minute before passing directly to a 15 cm diameter
horizontal bowl decanting centrifuge. Optimum centrifuge differential speed
and pond depth consistently produced performance data as outlined in Table 5.
The centrifuge cake solids were particulate in form and were further dewatered
in a pneumatic dryer to achieve a final moisture content of less than 7%.
314
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TABLE 5. CENTRIFUGE PERFORMANCE IN DEWATERING SLUDGE
RECOVERED AFTER CHEMICAL TREATMENT OF MEAT
PACKING PLANT EFFLUENT
Parameter Level Recorded
Sludge Flow (1/min) 20
Input Settleable Solids (%) 4
Centrifuge Cake Solids Content (%) 40
Centrate Settleable Solids (%) 0.3
Centrate Floatable Grease (%) 1.3
Settleable Solids Recovery (%) 92
By-Product Use as an Animal Feed
Clearly the value of any recovered by-product as an animal feed will in
part depend on the composition of the effluent treated.
By comparison with many present meat meal feed materials the recovered
by-product is generally low in protein and high in total grease content.
For this reason the product is used as a dietary supplement for non ruminant
animals, being incorporated in the feed at apportioned levels, often ranging
between 5-15% inclusion. For this application the by-product grease content
may be used in place of tallow, often added to feeds to improve the metabolic
efficiency. ME/CP Qfetabolisable Energy/Crude Proteins).
Comparison of supplements from the treatment of meat packing plant effluents
with that of a typical meat and bone meal show that the ranges for crude
protein, total grease, and ash content on a dry basis are as follows:
„ . Effluent Meat and Bone
Component =
c Supplement Meal
Crude Protein (Nx6.25) 20-35% 45-55%
Ash 20-35% 10-20%
Total Grease 20-40% 5-15%
The range reflects the variation between effluent from different meat packing
plants and the seasonal variations within a plant. Analyses also indicate
sufficient concentrations of essential amino acids such as lysine and
tryptophan for the feeding of these materials to hogs and poultry.
In the main broiler chicken feeding trials have been used to assess the
nutritive value of the effluent by-product. Compared to hog feeding trials
these have allowed for more extensive evaluations with the limited material
available. It was also considered chickens in broiler feed trials would be
315
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more susceptible to diet inadequacies than many other species.
A recent trial by the Poultry Research Centre in New Zealand to test the
feeding value of meat packing plant effluent by-product meal when fed to
broiler grower chickens showed that the Effluent Supplement resulted in
comparable growth to similar inclusions of Meat and Bone Meal (containing
50% crude protein). The effluent meal used in this trial had a nutrient
composition on a dry wt. basis as follows:
Crude Protein (Nx6.25)(%) 30.0
Ash (%) ~ 29.8
Total Grease (%) 30.0
The effluent meal and meat and bone meal supplements were individually
incorporated in separate diets with levels of inclusion ranging from 0-14%.
The broiler grower chicks were randomised over 74 quad boxes with 7 males and
7 females per box, and placed in tiered electrically heated battery brooders.
Evaluation of the results and an analysis of variance showed the effluent
by-product produced greater weight gain than the equivalent inclusion of meat
and bone meal over the three week growth period and that the rate of weight
gain to food consumed was similar for both diets. These results are shown
in Figure 4. The conversion of feed to body weight increased with increasing
inclusion for both diets and this is attributed to an improved ME/CP ratio.
No toxicity or palatability problems were encountered and in a separate trial
the effluent meal ash concentration (dry wt. basis: 43.6% Ca, 15% P) was
found to have no significant effect on growth for ash inclusions in the total
diet varying from 0-8%.
It was concluded the effluent by-product can perform as well as a meat and
bone meal and could be a useful dietary supplement in poultry rations and
hog diets. Results indicate a market value (April 1976) of approx. $(N.Z.)
90-100/tonne may be acceptable for a meal of this composition.
FULL SCALE PLANT DESIGN
Process performance has been consistent through the development stages of
laboratoty, pilot plant and full scale plant operation. A comparison of
laboratory and pilot plant results for the treatment of meat packing plant
effluent as discharged from a saveall is summarized in Table 6 and Figure 5.
Pilot plant operations treated 4 m^/hr of effluent as shown schematically
in Figure 1, with the by-product being recovered for poultry feeding trials.
The only large scale application to date has been a plant treating 110 nrVd
of effluent from a poultry processing operation. Pilot scale studies on the
treatment of meat packing plant effluent have led to preliminary full scale
plant design for a treatment plant to process 4500 m^/d of effluent with the
recovery of some 8 tonnes of dried by-product per day. Typical costs
(April 1976) for a plant to treat this volume of effluent and produce a dry
bagged by-product are in the range of $(N.Z.) 700,000-800,000.
In general the economic viability of such a plant is dependent on specific
plant locality and circumstances. However in one instance, for a specified
316
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CONVERSION OF FOOD TO
BODY WT. GAIN FOR EFFLUENT MEAL
AND MEAT & BONE MEAL FOR
P.R.C. POULTRY FEEDING TRIAL
0.40
0.35
(0
O
CO
0.30
£
0.25
0.20
<» Meat & Bone Meal
A Effluent Meal
Increasing Meal Inclusion
120 110 100 90 80
ME/CP Ratio
70 60
Figure 4
317
-------
oo
TABLE 6. COMPARISON OF LABORATORY AND PILOT PLANT PERFORMANCE FOR THE CHEMICAL TREATMENT OF A MEAT
PACKING PLANT EFFLUENT AS DISCHARGED FROM A SAVEALL SYSTEM
Mean Daily
Composite Value
Effluent Component"1" of Untreated
Effluent to
Laboratory and
Pilot Plant
Total Solids (mg/1)
Total Organics (mg/1)
Ash (mg/1)
Suspended Solids (mg/1)
Total Grease (mg/1)
Protein (Nx6.25) (mg/1)
Chemical Oxygen Demand (mg/1)
2480
1630
850
1400
310
940
1340
Mean Daily Mean Daily
Composite Value Percentage
of Treated Reduction on
Effluent from Pilot Plant
Pilot Plant
2070
450
1620
70
20
390
260
15
72
+91
95
94
59
81
Mean Daily Mean Daily
Composite Value Percentage
of Treated Reduction In
Effluent from Laboratory
Laboratory
1980
550
1430
30
20
430
220
20
66
+68
98
94
54
84
+ Analyses as per Standard Methods (2)
-------
COMPARATIVE REDUCTION IN
TOTAL ORGANICS OF MEAT PACKING
PLANT EFFLUENT ON THE PILOT PLANT
AND IN THE LABORATORY
2000
1800
1600
g» 1400
o 1200
O
O
O 1000
o
75
.o
800
600
400
200
© Untreated Effluent
A Pilot Plant Results
• Laboratory Results
(mean results for
2 consecutive days
operation)
9.00-H30 11.30-1.00 1.00-aOO 3.00-5.00
am Time(hr) pm
Figure 5
319
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reduction in effluent 5-day Biochemical Oxygen Demand (BODs) of 70%, the
capital cost was comparable with that for a biological trickling filter scheme
and considerably cheaper than for an ocean outfall. Operating costs for the
chemical treatment plant were higher than both of the other schemes,.however
the chemical treatment process did break even relative to the biological
process if $50-60 CN.Z., 1976) per tonne was obtained for the by-product.
Any higher values of the by-productwould indicate the chemical process to
be economically superior to the biological.
CONCLUSIONS
Laboratory and pilot plant studies on the application of the process
described to the treatment of meat packing plant wastes have shown that
effluent chemical oxygen demand may be consistently reduced by 75-80%.
The nutritive value of the recovered by-product compared favourably with
conventional meat and bone meal supplements for inclusions of up to 14% in
the diet of broiler grower chickens.
The process described may meet operating costs through the sale of by-products
and offer a significant return on capital depending on effluent composition
and plant locality: for example in an urban area where land availability is
limited and water supply and sewage charges are high.
ACKNOWLEDGEMENTS
The author wishes to acknowledge the financial and technical support of the
N.Z. Meat Industry, the N.Z. Poultry Research Centre, the N.Z. Development
Finance Corp., and in particular the efforts of Bill Wakelin and Eric Retter
of Morrison,Cooper and Partners.
REFERENCES
1. Grant, R.A., "Protein Recovery as an Effluent Treatment Process", Effl.
and Water Treat. Jour,, Jji, 616, (1975).
2. Standard Methods for the Examination of Water and Wastewater, 14th Ed.
Amer. Pub. Health Assn., New York, 1975.
3. N.Z. Patent 153129 "Improvements in or Relating to Processes for the
Purification of Waste Effluents and/or Processes for Extracting Protein
from Waste Effluents Containing the Same".
320
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WASTEWATER TREATMENT AND REUSE
IN AN INDEPENDENT RENDERING COMPANY
by
William R. Isherwood* and Jack McVaugh**
INTRODUCTION
In June 1975, SARS (South Alabama Rendering Company) of Loxley, Alabama,
received an NPDES permit requiring effluent modification of the plant's
existing discharge into a local river. By March 1977, SARS completed
and began operating a wastewater treatment system. This treatment facility
adequately reduces the contaminant levels and provides a method by which
the treated effluent can be recycled through the rendering process.
Simplicity of operation and recycling are major system achievements, and
are considered to be the main topics of this thesis.
Simple operation is a key consideration to the success of a well-function-
ing plant, and allows less sophisticated, and thus less expensive, operator
qualifications to be set. As was the case at SARS, no new personnel were
required, and actual plant operation was reduced to routine mechanical
maintenance of several new pumps and a blower.
Wastewater contaminant reduction is accomplished at SARS by biological
action in an earthen lagoon system. This treatment system is designed
to produce an effluent of such high quality that this effluent can be
partially or totally reused as condenser cooling water. Presently, the
entire effluent flow, 190,000 gpd, is being reused for cooling purposes,
with the remaining wastewater introduced to the treatment system being lost
through evaporation or lagoon leakage. At the prevailing treated effluent
contaminant levels, however, the system could discharge over 70,000 gpd
without exceeding NPDES permit levels. 100% recycling has been maintained
for over nine months with complete satisfaction. Thus, daily discharge
is zero. Biological degradation reduces organic contaminant levels in
excess of 95%.
*Ponder Engineering and Survey Company, Daphne, Alabama
**Envirex, Inc., Waukesha, Wisconsin
321
-------
The 1976 NPDES requirements were clearly met, and thus far the future
requirement—total waste discharge elimination—has also been achieved.
Of secondary interest, SARS has undertaken a pilot project by stocking the
aerobic polishing pond (part of the biological system) with catfish. The
fish are doing well and certainly contribute to the biological reduction
of the BOD introduced into the pond. More will be said of this later in
the text.
RENDERING PLANT AND OPERATION
SARS, Inc., located near Loxley in Baldwin County, Alabama, is an experi-
enced, well-established rendering company, constructed in 1954.
SARS operates a batch rendering process to produce quality greases and
tallow as well as dry "meat meal." These products are rendered chiefly
from slaughterhouse waste and restaurant meat scraps and grease, and some-
times fish scraps. The processed greases are used for such products as
feed, soap, lubricants, cosmetics, and cement additives, while meat meal
is used almost exclusively as a protein source for animal feed, such as
poultry feed and dry dog food.
The plant layout includes several buildings which enclose the entire
rendering process, plus an office building, personnel locker room and
shower head, boiler room, and maintenance building.
SARS rendering process is not unusual. Raw materials are trucked to the
plant daily and rendered into marketable products. The plant operates
five days each week, with daily operation beginning in the early evening
and lasting into the next morning. Average process time is 13 hours.
The first steps of the rendering process begin when the collection trucks
arrive in the afternoon. Scraps and grease are unloaded and weighed, and
solid raw materials are ground. Both the ground solids and grease are
then conveyed to the cooking room.
Cooking is accomplished in three large steam-heated ovens. Each oven is
individually loaded and sealed. Cooking begins and automated stirring
continues for about 2-1/2 hours per load, or until the moisture content
being monitored is sufficiently reduced. After cooking, the renderings
are removed from the ovens and strained. Grease is separated from solid
material and stored, but the solids are further processed by screw expellers,
producing dry meat meal and more grease. The dry meat meal is then milled
into a coarse powder. Both the meat meal and grease are stored onsite in
larger tanks.
PLANT WASTE
The plant is located on the headwaters of the Fish River, which offers
easily attainable non-potable water and a convenient waste carryoff.
SARS' rendering process requires a 550 to 750 1pm (145 to 200 gpm) cooling
322
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water supply which circulates through the barometric-leg condensers.
This cooling water is virtually free of contamination.
The main contaminating waste source is from washing of floors and equip-
ment after each day's operation. Spillage during truck unloading and
grinding is unavoidable. Much of this spillage can be reclaimed by dry
clean up measures, but always there is some grease, paunch manure, various
solids and small quantities of blood that can only be efficiently removed
by washing into conveniently-located floor drains. Slight spills and ac-
cumulated deposits are washed daily from the cooking and finishing areas,
and these are also collected by the floor drains.
Figure 1 shows the original sewerage system before modification. As shown
in Figure 1, a network of sewerage carried the wash water through two small
grease separators where grease is hand-skimmed and returned to the ren-
dering process. After passing these small separators, the wash water com-
bined with one-pass cooling water at the head of the large, 75 m3 (20,000
gallon) grease separator.
This separator, shown in Figure 2, and its operations deserve some comment.
By daily hand-skimming, the effluent grease levels averaged 40 mg/1.
The floating material recovery was 600 - 1200 Ipd (165 - 330 gpd).
The contamination in the effluent was certainly not a grease problem.
However, relatively large quantities of suspended solids contributed to
biological oxygen demand and turbidity, and SARS was definitely in need
of some sort of abatement process to control the contaminated effluent.
Table 1 lists the NPDES limitations set for SARS. The limitations, esta-
blished by the EPA, were based on a national average, and were particularly
evaluated for each rendering company on the basis of total pounds of raw
materials processed daily.
Upon issuance of the permit, it was immediately obvious to SARS that
their daily wastewater discharge need be reduced, or else a treatment sys-
tem be installed capable of producing effluent BOD 5 and TSS concentrations
less than 10 mg/1. Realizing the difficulty of the latter method, and no-
ting the production levels of the SARS plant, the Alabama Water Improvement
Commission suggested that an average discharge of 400 m3/day (100,000 gpd)
should not be an unrealistic goal. The design effluent ZOD^ goal was thus
approximately 15 mg/1. Data presented in Table 2 indicated that the
discharge flow had to be reduced by 33-50%. This was to be accomplished
by recycle of treated effluent for cooling purposes.
323
-------
P
OVEN LOADIWG DOCK
OVENS
TVPICAU
ont.Mtst
Figure 1. SARS rendering plant layout, showing original sewerage system.
324
-------
\ 1
\ 1
COOL.IMG
\NFUUEMT
PLAN
,. AFF-^.
-VV.1-.
b —
PX.UEMT
\
f
mm
J •
A
mm
mm
I
y ,
. • . • . . . . 4 . - - O ' • • ' - . 0' - . ' •
O
SECTION!
Figure 2. Final separator accomplishing 95% or better grease removal.
325
-------
TABLE 1. NPDES DISCHARGE LIMITATIONS
Effluent Characteristic
kg/day (Ibs/day)
Daily Avg. Daily Max
Flow—m3/Day (MGD)
Total Suspended Solids
BOD — 5-Day
Oil and Grease
Fecal Coliform
7.43(16.38)
6.02(13.26)
3.54( 7.8 )
14.86(32.76)
12.03(26.52)
7.08(15.6 )
Discharge Limitations
Other Units (Specify)
Daily Avg.
Daily Max
Flow—m3/Day (MGD) 400(0.10)*
Total Suspended Solids
BOD — 5-Day
Oil and Grease
Fecal Coliform 200/lOOml* 400/lOOml
*Alabama Water Improvement Commission Recommendation
326
-------
TABLE 2. 5-DAY DISCHARGE ANALYSIS
Characteristic
Analyzed Date Samples Taken (1975) Cooling
Water Grab
Composite Effluent Concentration mg/1 Sample mg/1
8/12 8/13 8/14 8/15 8/16 8/16
Flow-m3/Day 553 595 727 667 557
(MGD) (0.15) (0.16) (0.20) (0.18) (0.15)
Total
Suspended
Solids
BOD —
5 -Day
Oil and
Grease
Fecal
Coliform
(1000's)
45 143 56 97 91
56 263 117 225 88
12 48 16 45 34
430 930 2,400 4,600 2,400
9
2
1
1.5
WASTE TREATMENT
After evaluating the effluent, a table of flows and concentrations was
developed for treatment process design purposes (Table 3).
The maximum total daily flow was set at 795 m3/day (0.21 MGD) by taking
the maximum flow recorded and adding about 10%. Then, by measuring the
cooling flow alone, both the cooling water and the wash water flows were
determined.
It should be pointed out at this time that BOD and TSS were taken as the
main design parameters. This is because of the nature of SARS's waste.
Being organic and readily biologically degradable, it was felt that an
aerated lagoon would efficiently reduce BOD, followed by a polishing pond
to provide further BOD reduction and a place for solids to settle out.
Suspended solids in the wash water are mostly organic and make up a large
part of the BOD. The organic or volatile solids are aerobically converted
to non-degradable residue in the aerated lagoon.
327
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TABLE 3. DESIGN FLOWS AND CONCENTRATIONS
Influent Characteristic Quantity
Flow-m3/Day (MGD)
A. Total 795 (.21)
B. Cooling Water 720 (.19)
C. Wash Water 75 (.02)
Total Suspended Solids
A. Cooling Water < 10
B. Wash Water 1225
BOD — 5-Day mg/1
A. Cooling Water <£ 10
B. Wash Water 2250
Oil and Grease
A. Cooling Water < 10
B. Wash Water 800
As shown in Figure 3, the original primary treated effluent was the combi-
nation of cooling water and wash water flowing from the final separator.
As was mentioned earlier, the total discharge had to be reduced. The deci-
sion was made to recirculate, as cooling water, some or all of the poten-
tial discharge after treating to remove organic contamination.
The Implemented Plan
Reduction of organics was accomplished by isolating the wash water from
the cooling water and treating both individually. Since the wash water
has such a high BOD concentration (2250 mg/1), it is treated in two bio-
logical stages. The cooling water, on the other hand, is normally very
low in BOD and TSS, and needs only to be cooled somewhat to be good for
recirculation. The cooling water is, however, potentially contaminated
if the ovens are overloaded, causing a boilover into the cooling system
which must be caught and treated.
328
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COOLING
wArea
IMTAKE
SMA<_i.
SEPARATOR
J L
r--UJLLl
I
FlWAU
SEPAttATOa
FISM RIVER.
A
Figure 3. SARS1 original flow pattern.
Cooling water and wash water combined.
329
-------
Figure 4 shows the implemented plan. The wash water was segregated from
the cooling water just before entering the original final separator. A
new separator was constructed to remove grease from the segregated wash
water flow, and is also hand skimmed. From the separator, the wash water
is pumped to an earthen aeration basin.
The cooling water was left to pass through the original evaporator which
serves as a trap for grease if oven overloading occurs. After passing
the separator, the cooling water is pumped to the polishing pond where
it combines with the aeration basin effluent to make up the polishing basin
effluent.
The polishing pond effluent flows to a 5-foot diameter, 10-foot deep sump,
where pumps force recirculation as coolant. If the return is ever too
great for recycling, it will automatically overflow into a chlorination
basin for disinfection and then will be allowed to discharge into the
Fish River.
Aeration Basin
The aeration basin was required to provide the following:
1. A minimum of 90% BOD removal which is necessary to minimize the size
of the polishing pond and to assure adequate removal, satisfying the
NPDES limitations.
2. Sufficient volume to equalize the normally sporadic influent. Though
the daily wash water flow is only 75 nr* (20,000 gallons) per day,
this flow is realized in only 10 hours. Also, pumping the wash water
into the aeration basin causes severe flow variation during this period.
3. Simple operation, which is a primary consideration for a successful
treatment system of the small scale required by SARS.
4. Ease of construction as an earthen basin, sealed with heavy clay
material.
Considering these requirements, a basin with 20 days' retention was consi-
dered optimum. Equalization requirements were easily met with such a large
retention.
Ease of construction, along with low capital cost, determined selection
of the aeration device, a diffused aeration header consisting of fiberglass
pipes and fittings connected by mechanical couplings. The header took
approximately 12 man-hours to assemble.
Simple operation is inherent to an aerated lagoon. Operation of the
aerated basin at SARS is confined strictly to routine maintenance of the
blowers used in the diffused aeration system. A non-clogging, coarse-
bubble diffuser was selected for aeration, eliminating the need to dewater
the lagoon for periodic cleaning of diffusers. The lagoon dimensions
330
-------
POLISHING
POMD
A1
N
SHUT-OFF
IGE
I—
!
•-•N*
t±
-fr ->
I
A
A
JST
CONO.
•~^
new
SepARATor*.
i
1 !
1-
I
!K-
i . i
^y
XN
\
\.\\
Vh
MP
. .
-
™i
d
SEPAIIATOR.
STANDBV
I ^?TQ.EATED
I EFFLUENT
RIVER.
EXIST1KJG
Figure 4. The implemented treatment scheme providing
segregation of wash flows and cooling water.
331
-------
are 12 m (40 feet) by 30 m (100 feet) at the floor, and 3.7 m (12 feet)
deep with 3:1 side slopes.
BOD removal, mixing and air input requirements were calculated using
theoretical assumptions in lieu of pilot tests. The design predictions
were as follows:
1. BOD removal = 90 - 95%.
2. Horsepower required for complete mixing = 11.25.
o
3. Air requirements = 17 m /min. (600 cfm).
Since the plant has been in operation, it is realized that the BOD removal
and air requirements have been satisfied. Mixing requirements, on the other
hand, were initially greatly underestimated, but the aeration basin does
function adequately. Initially intended to operate as a completely mixed
aeration basin, the realized facilities operate as a facultative basin
with both aerobic and anaerobic BOD decomposition.
Polishing Pond
Because SARS recycles the effluent from the polishing pond as cooling water,
the retention time in days is strictly the pond volume—10,000 m^ (2.6 MG)
maximum, divided by the daily plant discharge. With no evaporation or
leakage, the minimum daily discharge is equal to the daily wash water flow
plus condensate. If daily discharge is 75 m3 (20,000 gallons), the reten-
tion in the polishing pond equals 130 days.
It is anticipated that long retention will allow a very stable ecological
balance in the polishing pond. This balance will assure good waste removal
characteristics. Should such a long retention period prove unsatisfactory,
however, the daily discharge can be increased to a maximum of 380 m3
(0.1 MG), allowing a retention period of only 26 days. The retention can
also be adjusted by changing the water level in the pond between 0.6 m
(2 feet) and 2 m (6 feet) in 0.3 (1 foot) increments.
ACTUAL PERFORMANCE
In mid-March 1977, construction was sufficiently complete to begin filling
the basins. By June, the first effluent was realized and as soon as pos-
sible thereafter an analysis of the polishing pond effluent was made.
The results, shown in Table 4, were somewhat disappointing, but the system
was very young. Suspended solids were fairly high but only due to initial
disturbance of the clay sealer used in the basins.
332
-------
TABLE 4. RANDOM DISCHARGE ANALYSIS
Effluent Characteristic
Total Suspended
Solids mg/1
BOD — 5-Day
Oil and Grease
Fecal Coliforra
100 ml
PH
Date: 6/9/77
113
35
1
**4,000
7
*Removal
90.8%
98.4%
99.9%
7/27/77 *Removal
49 96%
27 98.8%
1.2 99.9%
2 Excellent
Excellent
*Removal based on design concentrations shown in Table 3, i.e.,
TSS - 1225 mg/1, BOD - 2250 mg/1, Oil and Grease - 800 mg/1.
**Coliform is relatively high because chlorination equipment had
not been completed by this sampling date.
By mid-July, the system seemed better stabilized and another polishing
pond discharge analysis was made. The results, also shown in Table 4,
were more encouraging.
One effluent characteristic not included in Table 4 is daily discharge.
And to this date, no discharge from the system has been required. Several
times for testing and flushing purposes small discharges have been allowed;
otherwise, 100% recycling has been maintained. This is due to a reduction
in wash water utilization, normal evaporation, and leakage.
Because the polishing pond provided good results, SARS decided to stock
it with native freshwater catfish. A thousand fingerling fry were intro-
duced to the pond and seem to be doing well. The idea to create a well-
balanced ecological equilibrium seemed incomplete without catfish, and surely
they offer some assistance to the waste removal.
With no discharge, daily analysis was not required, and until mid-August,
no data was recorded. Envirex, Inc., the manufacturer of the aeration
equipment, offered to run an analysis consisting of three separate samplings
333
-------
to evaluate the treatment efficiency. Each analysis was to measure the
total and soluble BOD and total suspended solids of the untreated wash water,
in the aeration basins, and in the polishing pond effluent. Grab samples
were taken for each day's test, but the time the samples were taken was
changed to reflect various periods of the rendering schedule. The results
were averaged and appear to be a fair indication of the plant's behavior,
as shown in Table 5.
TABLE 5. AVERAGE TREATMENT EFFICIENCY ANALYSIS
Aeration Stabilization
Characteristic Influent Basin* Removal Basin* Removal
BOD — 5-day
mg/1 2260 305 86% 18 94%
Total Suspended
Solids mg/1 3672 2411 34% 39 98%
Soluble BOD —
5-Day mg/1 850 90
Overall Removal
BOD — 5-Day mg/1 99.2%
Total Suspended Solids mg/1 99%
Soluble BOD — 5-Day mg/1
*Effluent
To thoroughly understand SARS' or any treatment plant, samplings should
be continued until trends are documented for the seasonal changes. Under-
standably, however, SARS is reluctant to conduct such analyses if not re-
quired by the state regulatory agency. Recycling allows SARS zero dis-
charge and their adopted operation philosophy is as long as the system ap-
pears well, it is considered to be functioning properly.
Another point of interest is that during September of 1977 when the records
of the efficiency samples were taken, it was noticed that an algae bloom
was developing. Algae was, of course, prolific in the polishing pond
and was anticipated. Suspended solids in the pond are mostly algae and
these plants are considered advantageous in a well-balanced aquatic eco-
system.
334
-------
When the bloom was first observed, it was feared that treatment efficiency
might be falling off as a result, but one of the best test results was
received during this period. Suspended solids were still acceptably low.
The accelerated algae growth was short-lived. Within three weeks of the
initial sighting, the bloom dispersed.
ECONOMICS
The total cost incurred to implement this concept ran approximately
$300,000. Continued costs to SARS for the use of the treatment facilities
are the operation and maintenance for two 10-horsepower and one 3-horse-
power pumping stations, and two 15-horsepower aeration blowers. Of course
chlorine and maintenance of its associated equipment are a potential cost
if ever utilized, in the event that discharge of treated effluent to the
Fish River becomes necessary.
335
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THE IMPACT OF THE CLEAN WATER ACT OF 1977 ON THE
FOOD PROCESSING INDUSTRY
by
Carl Schafer*
A major legislative milestone in 1972 was the passage of the omnibus Federal
Water Pollution Control Act Amendments, P. L. 92-500. Among its many pro-
visions was one for midcourse corrections. After three years of study,
hearings, and debate, these midcourse corrections were signed into law on
December 27 as the Clean Water Act of 1977, P. L. 95-217.
The Philosophy behind the 1972 law was to "restore and maintain the chemical,
physical and biological integrity of the native waters." The Law called for
fishable and swimable waters by 1983 and a goal of zero discharge of pollu-
tants into major waterways by 1985.
Instead of using water quality standards to control pollution, an approach
that produced uneven results, the 1972 law shifted to a permit system.
Dischargers had to limit the amount of pollutants according to Federal
guidelines or "effluent limitations", that were based on the level of cleanup
possible with certain technologies.
By July 1, 1977, industry was required to meet standards set using "best
practicable technology (BPT)." By 1983, as new and more effective equipment
was developed, the effluent limitations were to reflect the cleanup possible
with the "best available technology economically available (BAT)."
The Clean Water Act of 1977 generally preserves the substantive aspects of
The Federal Water Pollution Control Act (P.L. 92-500). Changes are in the
nature of "fine tuning" in the area of statutory thrust. The new Act is more
realistic and directs priorities towards the control of toxic pollutants.
The transition from rather broadly worded provisions in P. L. 92-500 regard-
ing industrial point source controls, including effluent limitations, to a
more realistic structure of pollutional controls was effected by definition
of three characteristic groups of pollutants—each with its own regulatory
and administrative requirements. Thus we now have three types of technology-
based effluent control groups; toxic compounds, conventional pollutants and
non-conventional pollutants.
*Division Director, U. S. Environmental Protection Agency, Industrial and
Extractive Processes Division (RD-681) Washington, D. C. 20460
336
-------
Toxic compounds are basically the 65 classes of toxic compounds incorporated
into the new statute in Section 307 from a consent decree agreement entered
into by the Environmental Protection Agency (EPA) and the Natural Resources
Defense Council (NRDC). Control of these pollutants will be through effluent
limitations established with "best available technology" (BAT) requirements.
These effluent limitations will be promulgated by EPA no later than July 1,
1980 and they must be achieved by no later than July 1, 1984 by those classes
and categories of industrial point sources identified by EPA as being subject
to this requirement. There will be no economic or environmental variances
granted from BAT effluent limitations and effluent standards for "toxic"
pollutants.
For the present, the types of industry concerned with toxic pollutants are
the 21 "heavy" industry categories covered by the consent agreement. Food
processing industry categories are not now specifically affected by this
program. However, sampling of food processing plant effluents for possible
toxic components is an important part of EPA's research program in the area
of industrial wastewater treatment.
Pollutants of essential interest to the food processing industry are those
that fall under the new category of conventional pollutants. The pollutants
include biochemical oxygen demand (BOD), suspended solids (TSS), pH, fecal
coliform and potentially others in the "traditional" sense as may be defined
by the Aministrator pursuant to Section 309.
Technology-based limitations are still required; however, a new level of
technology is to be defined for establishing limits for these pollutants;
namely, "best conventional pollutant control technology" or BCT. This
technology requirement has been defined by the Congress to include the
technical factors originally used to define BPT and BAT requirement, but
with a new "cost test."
The cost test is comprised of two essentially interrelated factors:
(1) reasonableness of the relation between the cost and the effluent reduc-
tion benefits; and (2) comparison of the industry category or subcategory
cost and associated pollutant reduction for publicly owned treatment works.
The cost test is to be applied to any forthcoming future regulations
establishing limitations for conventional pollutants. Thus, for example,
(with resources permitting) regulations not previously finalized in indus-
tries such as poultry processing, miscellaneous food specialities, beverages,
edible oils, and others would be finalized as BCT regulations.
In addition, the statute requires the Agency to review the "old" BAT
limitations for conventional pollutants for the industries not covered by
the toxic limitations program. These industries (so called "secondary
industries" as a term to differentiate them from the heavy "primary
industries") include all of the food processing categories and subcategories
for which BAT limitations were promulgated and in effect at the time of
passage of the Clean Water Act. Specific food industries covered in this
review are all subcategories of the fruits and vegetables, meat products,
seafoods, dairy, sugar, and grain mill processing industries.
337
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A brief description of the review process may be helpful. The secondary
industry review involves some 14 industry categories and over 200 subcate-
gories. All data as to costs, level of pollutant reduction and specific
limitations requirements were assembled and reviewed. Initial review
focused on defining the population of subcategories for which the "cost
test" must be performed. Thus, for example, about half the subcategories
for which BPT was zero discharge or where BPT and BAT requirements were
equal were screened out of the review. Coincident with this screening
process, costs and performance relating to POTW control of conventional
pollutants were compiled. Cost comparisons were made on an incremental
basis, i.e. the cost and pollutant reduction going from BPT to BAT for
industry vs. the POTW counterpart going from average (or good) secondary
treatment to best secondary treatment.
Section 301 requires classes and categories of industrial point sources
discharging "conventional" pollutants to achieve by not later than July 1,
1984, effluent limitations requiring application of BCT to be defined by
EPA. Again, there will be no economic or environmental variances granted
from BCT effluent limitations for conventional pollutants.
The third group of pollutants are those which are not specifically listed
as either "toxic" or "conventional" and are therefore termed "non-
conventional." These pollutants are to be regulated by BAT level technology
standards. Section 301 (b) requires category and classes of industrial
point sources which discharge other than toxic or conventional pollutants to
achieve BAT by July 1, 1984 or within three years after promulgation by EPA,
but in no case later than July 1, 1987.
In contrast to requirements for conventional and toxic pollutants, owners or
operators are entitled to apply for a waiver from the BAT requirements for
"non-conventional" by one or both of two mechanisms: (1) Section 301 (c) which
allows waivers based upon economic circumstances (affordability) of the
permittee while at least BPT is achieved; and (2) Section 301 (g) which
allows for waivers based upon environmental considerations among which are
that (a) water quality standards are being achieved, (b) if a waiver is
granted, no other point source will have to upgrade treatment to compensate
for the waived requirements, and (c) at least BPT is being met. In addi-
tion, it should be pointed out that the compliance date for toxic pollutants
can be extended to July 1, 1987 if the facility is going to employ an
innovative production process or new treatment technology which will result
in a greater effluent reduction than required or significantly lower costs
for reaching the required reduction.
Although the provisions of the new law relative to effluent limitations are
of major interest to the food processing industry, there are other features
of the Act which are also of interest to this industry. In regard to
industrial cost recovery (ICR) payments, EPA is required to study the
efficiency of, and the need for, such payments. This study is to include,
but is not limited to, an analysis of the impact of ICR payments on rural
communities and on industries in economically distressed areas or areas of
high unemployment. The study is to be completed and submitted to the
338
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Congress within twelve (12) months after December 27, 1977. In addition,
Section 204 (b) allows POTW managers to reduce the amount of ICR payments
where an industrial user reduces its total flow of sewage or unnecessary
water consumption. This section also exempts from ICR requirements those
industries discharging 25,000 gallons or less per day into municipal
treatment plants as long as the effluent does not contain toxic chemicals
or other materials that would contaminate or reduce the utility of the
resulting sludge.
The Act specifically defines irrigation return flows and their cumulative
effects as non-point sources. Further, the Department of Agriculture is
authorized to establish and administer a cost sharing program to assist
farm owners and operators to install and maintain measures necessary for
control of non-point sources of water pollution. Grants may not exceed 50
percent of approved non-point source pollutant abatement measures.
Industrial direct discharge plants unable to meet the July 1, 1977 date for
compliance with best practicable technology (BPT) because of contemplated
future discharge into a POTW may submit a request to appropriate NPDES
permit issuing authorities for extensions of time (but no later than July 1,
1983). Time extensions up to April 1, 1979 may be granted by NPDES permit-
issuing officials to industrial plants not contemplating discharge into
POTW's if it is found that the discharger has acted in "good faith" and if
facilities necessary to comply with the BPT requirements are under construc-
tion.
EPA is required (by the Act) to conduct a study of the effect of the disposal
of seafood processing wastewaters into marine waters. The study is to
examine the geographical, hydrological and biological characteristics of
marine waste-waters into which such wastes are discharged. In addition, the
study is to examine technology which may be used to facilitate the use of
nutrients in seafood processing waste waters or which may be used to reduce
the discharge of such wastes. The result of the study is to be submitted
to the Congress no later than January 1, 1979.
Although it was not incorporated into the final version of the Act, the
legislative conference report directed the Administrator to conduct a study
to be completed by January 1979 to ascertain if there is merit to argument
that some Virgin Islands and Purerto Rico rum distillers might safely
dispose of certain natural wastes untreated into the marine environment. In
this study the Administrator should specifically examine geographical,
hydrological and biological characteristics of marine waters receiving such
wastes to determine if the discharge can be environmentally acceptable either
for the purpose of aquaculture or some other purpose. In addition, the
study should examine technologies which might be used in these industries to
facilitate the utilization of the valuable nutrients in these wastes or the
reduction in the discharge to the marine environment.
I have tried to discuss the provisions of the new law which will have the
most impact on the food processing industry. In general, the new law
stresses innovative, alternate wastewater treatment technology (recycling
339
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and reuse of wastewater including sludge, land treatment, and methods to
decrease wastewater volume) with an emphasis on the importance of control-
ling toxic pollutants. I would like to take this opportunity to encourage
each of you to carefully review the new act and EPA's proposals for imple-
mentation and to provide us with comments on those aspects you feel are
appropriate.
340
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THE APPLICATION OF DEEP SHAFT TECHNOLOGY
TO THE TREATMENT OF FOOD PROCESSING WASTEWATER
by
D.S. Sandford, P.Eng.* and T. Gallo, P.Eng.**
INTRODUCTION
The Deep Shaft Effluent Treatment System is a high rate activated sludge pro-
cess. It was developed by Imperial Chemical Industries in Great Britain in
co-operation with various ICI subsidiaries around the world. The responsibil-
ity for the development of the technology in North America rests with Canadian
Industries Limited, (CIL), through their wholly owned subsidiary, Eco Research
Ltd. of Montreal, Quebec, Canada. Marketing of the technology in the United
States is the responsibility of CIL-Chemicals, Inc. of Detroit, Michigan, also
a subsidiary of CIL.
The North American version of the technolgoy features the Deep Shaft concept
for aeration but utilizes flotation as an effective method of solids separa-
tion rather than conventional gravity sedimentation.
Initial work involving flotation as a method of achieving reliable suspended
solids separation was demonstrated at Emlichheim, W.Germany where a Deep
Shaft roughing treatment plant was built to treat potato processing wastewater
for the KSH Company(1).
The Deep Shaft Effluent Treatment System is proving to be highly effective for
the treatment of high strength readily biodegradable wastewaters which are
normally found in the food processing industry.
The Deep Shaft Effluent Treatment System has also been successfully applied
to the secondary treatment of municipal and industrial domestic blends of
wastewater(2)(3)(4). North America's first full-scale autonomous Deep Shaft
plant is currently under construction at the Town of Virden, Manitoba and is
designed to treat the entire town's wastewater (ie. 5,000 population equiva-
lent) .
Several technical articles will be presented in the next twelve months regard-
ing the operation of a Canadian Deep Shaft demonstration plant that has suc-
cessfully treated brewery wastewater(5)(6).
Anheuser-Busch, Inc. of St. Louis, Missouri will be one of the first American
corporations to pilot Deep Shaft technology. The Deep Shaft pilot plant at
Anheuser-Busch in Williamsburg, Virginia will start-up in early April 1978.
*Eco Research Ltd.; Calgary, Alberta, Canada
**Eco Research Ltd.; Toronto, Ontario, Canada
341
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Interest in the technology is growing in all sectors of the food processing
industry, as industrial surcharges and land values increase.
This paper should provide an overview of the operation of a Deep Shaft demon-
stration plant which has treated brewery wastewater at Molson Breweries of
Canada Limited at Barrie, Ontario, Canada and a pilot plant operating on
dairy waste for the Co-operative Agricole de Granby, Notre Dame du Bon Conseil,
Quebe c, Canada.
The information collected in the course of this work enables us to develop,
with a high degree of confidence, cost estimates and designs for full-scale
brewery and dairy applications.
PROCESS DESCRIPTION
Coarse screening and grit removal are normally the only forms of pretreatment
which proceed the Deep Shaft Effluent Treatment System. Primary clarification
is not required in advance of the Deep Shaft bioreactor. Aeration takes place
in a totally cased and grouted shaft 100 - 250 metres (300 - 800 feet) in
depth, which is divided into a downcomer and riser section by a partition or
a concentric tube arrangement. The wastewater is circulated around the shaft
using the airlift principle. As the circulating mixed liquor in the shaft
reaches the surface, the entrained air bubbles are allowed to escape and a
portion of the flow is fed by gravity to a flotation cell for solids separa-
tion while the remainder of the flow is recycled back to the shaft.
The advantages of the Deep Shaft bioreactor arise from the geometric configur-
ation of the shaft.
As the injected air in the downcomer is entrained in the downward flowing
wastewater, it experiences an increase in hydrostatic head resulting in dra-
matically improved oxygen transfer due to increased oxygen solubility in
the lower regions of the shaft. This results in a more complete and effec-
tive oxygen penetration into the floe. Thus, oxygen utilization by the biota
becomes the limiting process rather than the transfer of oxygen to the biota
as in conventional systems.
The healthy physiological environment created in the bioreactor for the biota
appears to result in a considerably higher kinetic rate than in conventional
activated sludge systems. Therefore, Deep Shaft bioreactors tend to be
extremely small in volume when compared to conventional systems.
The air that is added to the bioreactor to supply oxygen to the biota also
provides the driving force for hydraulic circulation and suspended solids
separation in a flotation cell following the Deep Shaft bioreactor. These
are the major reasons for the exceptional power economy attained by the
system.
The increased dissolved oxygen in the bioreactor, coupled with high turbu-
lence, results in a highly aerobic, well oxygenated biomass and prevents the
development of filamentous organisms. The turbulence in the bioreactor tends
to comminute filaments, resulting in short, easily separable fragments.
342
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The plug-flow nature of the shaft, preceded by complete mix circulation at
the top of the shaft, is effective in diluting influent BOD5 and reducing pH
shock loads.
The metabolic cycle of the biomass in the Deep Shaft bioreactor, the result
of plug-flow mode of operation, may be responsible for the lower sludge pro-
duction experienced in Deep Shaft plants when compared to other high rate
activated sludge systems.
The subsurface placement of the shaft and the large recirculation volume en-
sures a near constant temperature in the shaft all year round which is of
particular importance in extreme climates.
Since the Deep Shaft Effluent Treatment System is highly aerobic, there are
no putrescent odors. This, coupled with the small surface area requirements
of the technology, allow plants to be totally enclosed resulting in a very
favorable working environment.
The flotation mode of suspended solids separation is significant since:
(a) A reduction is possible in the size of suspended solids separation
equipment because the rise rates in a Deep Shaft flotation cell are
3-4 times that of conventional clarifier settling rates.
(b) The efficient use of readily available dissolved gas allows a high
concentration of mixed liquor suspended solids to be separated
efficiently.
(c) Floating sludge is thickened to 4-8% in the flotation cell elimin-
ating the need for sludge thickening equipment and the associated
energy costs.
Figure 1 and 2 illustrate the process schematics used to demonstrate the via-
bility of the Deep Shaft Process to treat dairy and brewery wastewater respec-
tively.
DAIRY WASTEWATER TREATMENT
Wastewater from the cheese and powdered milk producing plant of the Co-oper-
ative Agricole de Granby at Notre Dame du Bon Conseil, Quebec, Canada has
been successfully treated using the Deep Shaft Effluent Treatment System.
The pilot plant consisted of an 20 cm x 157 m (8" I.D. x 500') deep shaft
containing a 6.76 cm (2.66") I.D. U-tube bioreactor. Solids separation was
accomplished in a separate cell following the bioreactor.
The results of the pilot plant study provide the design criteria enabling Eco
to design full-scale Deep Shaft dairy wastewater plants. Figure 1 shows the
schematic of the plant.
As the full-scale plant is expected to operate at higher than ambient temper-
ature, provision was made for controlled heating of a water jacket.
343
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DEEP SHAFT
<3-
A
POLYMER
MIX
V
V
i
J
{
T
i
\7
SINK RECYCLE
SOLIDS SEPARATION
FIGURE 1, BON CONSEIL DEEP SHAFT
PILOT PLANT SCHEMATIC,
INFLUENT
UREA
•EFFLUENT
-------
FIGURE 2, MOLSONS DEEP SHAFT DEMONSTRATION PLANT
BARRIE, ONTARIO, CANADA.
BREWERY
.—' 300 GPM
CO
-P»
U1
EFFLUENT
^/ 50
COo
>
;
GPM
50,000
EQUALI
TANK *
+> ADJUS1
: ^
i
^
GAL
ZING
, PH
"ME NT
4,000,000 GAL
AERATION
CELLS
CLARIFIERS
TREATED
EFFLUENT
->SEWER
SLUDGE RETURN
OPTIONAL RETURN LINE
TREATED
-EFFLUENT
FLOTATION
TANK
260 ft'
FLOW
CONTROL
800 ft
-------
Air is added to the downcomer side of the shaft as a source of biological
oxygen. Pilot scale shafts require additional air to maintain circulation
and this can be provided by adding airlift on the riser side of the shaft or
by the provision of mechanical pumping.
The head box provides the free surface area necessary to allow disengagement
of gas bubbles. Dissolved gases in the riser side of the shaft slowly come
out of solution forming microscopic bubbles which attach to the floes, creat-
ing the driving force for suspended solids separation by flotation.
The solids separation tank is cylindrical with a conical bottom. Provision
is made to collect both floating and settled solids. Collected bottom and
top solids are returned to the shaft.
The shaft was drilled in February and March of 1977 and the plant was ready
for commissioning in early May 1977. The objective was to define the Deep
Shaft operating and design parameters for dairy treatment.
The results on a one week intensely monitored period, as presented below,
were undertaken from October 25 to November 1, 1977 at which time the plant
was operated continuously with 24 hour per day supervision. Various streams
were analyzed including influent, mixed liquor, effluent and wasted sludge at
1 or 2 hour intervals.
The
operating conditions for the test period are outlined in Table 1.
TABLE 1. BON CONSEIL DEEP SHAFT PILOT PLANT
OPERATING PARAMETERS
SEVEN DAY INTENSIVE TEST PERIOD
Parameter Metric USA
Feed Rate 8.74 ± .08 m3/hr. 0.5 ± 0.05 USGPM
Bottom Recycle Rate 8.74 m3/hour 0.5 USGPM
Air Injection Rate 8.5 N m3/hr @ 690 KN/m2 5 SCFM @ 100 psig
Mixed Liquor Temperature 32 C 90°F
Mixed Liquor Suspended Solids 5,000 mg/1 5,000 mg/1
In late November 1977 a series of tests were conducted on a feed prepared by
dissolving dry whey powder in tap water and feeding this to the shaft, allow-
ing drastic fluctuations in the loading resulting in variable sludge ages and
changing physiological conditions. During the last period of this two week
experiment, alum was added to determine its effects on overriding fluctuating
load and to improve effluent clarity. Drastic improvements in the floating
346
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behavior of the sludge occurred, providing alum was added to the shaft at a
concentration of 1 mg of trivalent aluminum/gram of MLSS. The suspended
solids concentration in the effluent was reduced to a level averaging 49 mg/1
in 24 hour composites during the final six days of the tests. Since these
values were obtained on dissolved whey powder, normal dairy wastewater should
result in better sludge characteristics and solids separation.
Sludge production has been measured to be 0.5 kg of sludgeAg of BOD treated.
Consideration has been given to suspended solids escaping in the effluent.
Healthy microflora included bacteria of diverse morphology (ie. cocci, bacil-
li, long thin rods and occasionally fragments of filaments). Protozoa present
in the healthy sludge include colonies of Opercularia and active Vorticella.
No visible difference in the diversity of the microflora was observed whether
dairy waste or whey was being treated. The floes produced by artificial whey
influent looked more open and fragile than floes produced by dairy feed.
Filamentous organisms often plague conventional dairy waste treatment plants,
however filamentous bacteria were only observed on rare occasions when the
shaft did not receive adequate oxygen for reasons of foaming or organic over-
loading. No filamentous bacteria occurred after excess oxygen was provided
to take care of all load conditions.
Provision was made for continuous monitoring and control of pH of the mixed
liquor. It became evident that the mixed liquor was naturally buffered be-
tween a pH of 6.9 and 7.6. No additional acid or alkali was required to
keep the pH in this range, although the client's record of raw dairy effluent
pH showed a dramatic fluctuation between 2 and 12.
Discussion of Process Behavior During Seven Day Intensive Study
Results of Seven Day Intensive Study
Table 2 outlines the results of the seven day intensive study conducted be-
tween October 25 to November 1, 1977.
The results of the seven day intensive study indicate that an effluent of
less than 150 mg/1 suspended solids can be attained without the use of coag-
ulant aids.
Throughout the seven day intensive study, the load fluctuated sharply over a
twenty-fold increase in conventional F/M (ie. 0.18 - 3.2 days ) without up-
setting the substrate removal efficiency or solids separation efficiency of
the system. A sudden change in waste characteristics (ie. whole dairy waste
to whey) may require several hours of biomass acclimatization, however
equalization should reduce this impact.
All components in the influent appeared to be treated, in fact butter fat
actually aids flotation while milk proteins cause foaming in the head tank
which can be easily controlled with a mechanical foam breaker.
347
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TABLE 2. BON CONSEIL DEEP SHAFT PILOT PLANT
SEVEN DAY INTENSIVE STUDY PERIOD
PERFORMANCE
Parameter
Total BOD5
Total SS
FOG
Influent
(mg/1)
1597 (S)
498
388
Effluent
(mg/1)
125(b'c)
138
76
Removal Efficiency
(%)
98.3
72.3
80.4
Note; (a) BOD5/COD ratio =0.7
(b) Filtered BOD5 =25 mg/1
(c) Filtered COD = 181 mg/1
Changes in the nature of the waste (ie. milk to whey) during the test period
required several hours of acclimatization, however some relief from large and
rapid variations in waste characteristics for full-scale plants can be buffer-
ed with an acceptable degree of equalization.
Full-Scale Deep Shaft Dairy Plant Cost Estimate
Table 3 describes the influent of a 64 m3/hr. (0.4 mgdUSA) full-scale Deep
Shaft plant to treat high strength dairy wastewater to 50 mg/1 6005 and 50 mg/1
TSS specifications.
TABLE 3. DEEP SHAFT DAIRY PLANT COST EXAMPLE
WASTE CHARACTERISTICS AND TREATMENT
Equalized Daily Flow
Total BOD5
Effluent TSS and BOD
Population Equivalent
64 m3/hr. (0.4 mgd USA)
2400 mg/1 ± 30% fluctuation
50 mg/1
38,000 people
Table 4 describes the design parameters and capital cost for the full-scale
dairy Deep Shaft plant. The Deep Shaft portion of the plant offers excellent
space economy. It is estimated that a 64 m3/hr. Deep Shaft plant would require
less than 344 m2 (3,700 ft2) to enclose including preliminary treatment and
solids handling.
348
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The power economy for the Deep Shaft plant is estimated at three times that
of a conventional plant. The power economy for Deep Shaft plants is esti-
mated at 3.6 kg O2 transferred/kWh.
A sludge concentration of 5% by weight due to the thickening in the flotation
cells reduces sludge handling and disposal costs when compared to convention-
al systems using sedimentation which produces solids prior to dewatering or
stabilization at 1-2% concentration.
TABLE 4. DEEP SHAFT DAIRY PLANT COST EXAMPLE
Shaft Dimensions
Plant Surface Area
MLVSS
Sludge Production
Waste Sludge Concentration
Energy
Oxygen Transfer
Power Economy
Capital Cost
Metric
1.6 m x 250 m
350 m2
6500 mg/1
0.5 kg dry solids
kg 8005 removed
5%
109 kW
9,409 kg O2/day
3.6 kg O2AWh
$1.5 million
U.S.A.
63" I.D. x 800'
3700 ft2
6500 mg/1
0.5 Ibs dry solids
Ib BODr removed
5%
145 HP
20,700 Ibs 02/day
5.95 Ibs O2/HP-hr.
$1.5 million
The operating costs for the plant are outlined in Table 5. An aeration cost
of 4.7£/m3 (17
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TABLE 5. DEEP SHAFT DAIRY PLANT COST EXAMPLE
Operating Cost/Yr.
Manpower 10,000
Energy2 25,000
Chemicals3 1,000
Sludge Disposal4 60,000
Maintenance^ 7,500
Nutrients6 7,000
$110,500
Operating Cost Assumptions
1. Manpower based on h day attendance/day.
2. Energy based on $233/kWh ($175/HP/yr.).
3. Chemicals based on alum @ 1 mg Al /g MLSS.
4. Sludge disposal based on $0.27/metric ton-km hauling
costs, assuming 16 km transport.
5. Maintenance based on h of one percent of capital cost.
6. Nitrogen required at 100:10:1.
BREWERY WASTEWATER TREATMENT
A Deep Shaft demonstration plant was constructed in 1976 at Molson's Brewery
in Barrie, Ontario, Canada to investigate the potential for the process to
treat brewery wastewater and to develop design information to allow full-scale
brewery Deep Shaft Effluent Treatment plants to be built. Molson Breweries of
Canada Limited were attracted to the Deep Shaft Process in view of potential
savings in land, potentially less sludge for disposal and the apparent energy
savings that the technology offers. A schematic of the existing wastewater
treatment plant is shown in Figure 2. The existing extended aeration efflu-
ent treatment plant at Molsons has been very effective in meeting the exist-
ing 300 mg/1 8005 and 350 mg/1 TSS pretreatment guidelines established by the
City of Barrie.
350
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Operating experience has shown that the Molson's Deep Shaft can be effective-
ly used for biological treatment and sludge thickening or digestion of waste
activated sludge from the extended aeration plant.
The Deep Shaft hardware at Barrie is considerably different that the U-tube
pilot plant at Notre Dame du Bon Conseil, in that the Molson's Barrie plant
is a prototype. The shaft consists of an 0.46 metre (18") I.D. steel casing
157 metres (5101) deep grouted in a drilled hole 0.62 metres (24") I.D. Fol-
lowing the Deep Shaft headworks, a rectangular flotation cell receives parti-
ally degassed effluent. The flotation cell has a top and bottom rake and
scraper arrangement. The effluent from a flotation cell passes over an ad-
justable effluent weir.
Molsons provide approximately 9,042 m3 (62,500 USG) of surge tank capacity in
view of influent hydraulic and organic load fluctuations.
The ratio by weight of 6005 to ammonia, nitrogen and orthophosphate was
100:.31:.22. It was determined eventually that this situation created a nu-
trient deficient biological condition in the shaft and resulted in unpredict-
able sludge behavior detrimental to the performance of the Deep Shaft Process.
Urea and phosphoric acid were added to bring the BOD to nitrogen to phosphorous
ratio to an acceptable level of 100:8.7:1.3 during the thirty-one day August/
September 1977 evaluation period. It has been established that approximately
half of the nutrients are bioavailable in the effluent and therefore only half
of this value will have to be added. Therefore, for the purpose of cost esti-
mates, the nutrient addition requirement of 2.5 kg of ammonia, nitrogen and
0.5 kg of orthophosphoric acid are required for 100 kg of BOD5 in the influ-
ent.
Pretreatment consists of screening which removes particles in excess of 0.64
cm (V) in diameter.
The plant was commissioned in October 1976, however it was not until August
of 1977 after several developmental modifications that the plant could be
properly evaluated as a BOD and TSS removal system.
One basic difference between the Deep Shaft and extended aeration plant was
in the nature of the sludge. There were never filamentous organisms in the
Deep Shaft sludge which was in complete contrast to the extended aeration
sludge. The Deep Shaft sludge contains many types of protozoa including
stalked ciliates, which are indicative of a healthy biomass culture. Specific
oxygen uptake rates were measured and were found to be in the range of 8-20
mg/g/hr.
The Deep Shaft plant at Barrie was operated in the flotation mode for six
months and the 8005 and TSS removal was within the City of Barrie industrial
bylaw effuent specifications of 300 mg/1 BOD5 and 350 mg/1 TSS.
The existing Deep Shaft mechanical configuration has not operated optimally
in a flotation mode for mechanical reasons; however, all parties involved are
in agreement that solids separation by means of flotation is entirely feasible.
351
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Modifications planned for April of 1978 will correct this problem resulting
in excellent flotation. The results of a 31 day intensive study evaluation
period presented herein are based on the flotation cell operating successful-
ly in a clarifier mode. Reliable flotation has been demonstrated at the Paris,
Ontario Deep Shaft demonstration plant and at Emlichheim, W.Germany as discus-
sed elsewhere(1)(4). Therefore, Eco is confident that excellent flotation
can be achieved at the Molson's Deep Shaft plant with some minor modifications.
The successful operation of the Deep Shaft plant during the one month test
period between August 18 and September 18, 1977 is presented in Table 6.
TABLE 6. MOLSONS1 DEEP SHAFT DEMONSTRATION PLANT
ONE MONTH TEST PERIOD(6)
Parameter Influent Effluent Removal Efficiency
(mg/1) (mg/1) (%)
TBOD5 2624 109(a) 95.8
TSS 1208 257 78.7
(a) soluble effluent BOD5 = 18
The operation parameters during the one month intensive test period are shown
in Table 7.
Settling rates in the clarifier (ie. flotation cell) are up to 4 m/hr. with
a stirred volume averaging 59 ml/g. The presence of aluminum in the influ-
ent originating from the bottle washing operation, accentuates the successful
coagulation and flocculation that occurs.
Total excess activated sludge wasted as a result of biological treatment in
the Deep Shaft system over the 31 day period, was estimated at 0.71 kg of
sludge/kg of BOD5 removed.
Power economy in the shaft was estimated at 1.7 kg of 8005 removedAWh (2.8
Ibs of BOD 5 removed/HP-hr.) on the average and 3.2 kg of BODg removed/kWh
(5.2 Ibs of BOD5 removed/HP-hr.) on peak loading. However, since an equal
amount of air was being added at all times, 0.2 - 1.4 kg of 8005 were oxidiz-
ed/kg of oxygen applied depending upon the BOD loading. This is probably due
to the initial absorption of colloidal BOD5 onto the floe which is further
oxidized at a later time depending upon the sludge age. Full-scale shaft
designs may include a device to vary the air delivery in accordance with
changes in base line organic loading.
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TABLE 7. MOLSONS' DEEP SHAFT DEMONSTRATION PLANT
ONE MONTH PERIOD(6)
Operational Parameter
Flow
Equalization
TBOD5(in)
TSS (in)
Oxygen Transfer
Power Economy
Sludge Production
Energy
Solids Concentration
BOD5:N:P
MLSS
Metric
5.73 m3/hr.
9,042 m3
2624 mg/1
1208 mg/1
500 kg/day
2.8 kg 02/kWh
0.71 kg sludge
kg BODg removed
7.5 kW
3-4%
100:8.7:1.3
5000 ppm
U.S.A.
0.036 mgd(USA)
50,000 gallons
2624 mg/1
1208 mg/1
1100 Ibs/day
4.6 Ibs O2/HP-hr.
0.71 Ibs sludge
Ib BOD5 removed
10 HP
3-4%
100:8.7:1.3
5000 ppm
Proper equipment installation and energy conservation measures could increase
power economics to 6 kg of BOD5/kWh (10 Ibs of BOD5/HP-hr.) on full-scale
plant designs.
It is apparent that the flotation tank operating as a clarifier can operate
successfully at 8.59 m3/hr. (37.5 US gpm) and 5,000 ppm MLSS.
The proper design of other pilot plants confirm that a proper anticipation of
air loading to the shaft and consequently its effect on gas stripping should
allow optimized flotation design of the Barrie Deep Shaft plant at 8.59 m3/hr.
(35 gpm) and 8,000 MLSS.
Complete equalization of the waste is not deemed necessary, even at higher
F/Ms, but it is recommended that 6 hours residence time be provided at the
Barrie plant.
Deep Shaft waste activated sludge stability has not been studied in detail,
however while operating the shaft as an aerobic digestor over a four day
period, it was observed that the specific oxygen uptake of the sludge could be
353
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reduced by 88% at a shaft temperature of 20°C. Laboratory studies indicate
that a 93% reduction is possible at 25°C and this is accomplished by a 34%
weight reduction to provide a sludge with only 62% MLVSS.
Preliminary indications suggest that Deep Shaft activated sludge could be
dewatered to 20% solids using a filter aid, such as ferric chloride.
The Advantages of Flotation Over Sedimentation
Flotation generates 4% solids and.allows mixed liquor concentrations of 1%
in the shaft at a recycle rate of 50%. Sedimentation is generally limited to
1.5% settled solids at .75% mixed liquor and 100% recycle. Sludge volumes
are therefore, drastically smaller when flotation is used as a method of
solids separation. Subsequently, the cost of Deep Shaft systems using flo-
tation is lower.
Flotation rise rates tend to be 3 times faster than settling rates, which
results in smaller flotation cells and a reduced length of time that the
biomass is outside of the shaft.
The advantages of flotation are associated with the synergistic effect of
using the same air for biological aeration, hydraulic circulation and as a
driving force for solids separation.
The more concentrated solids float is less expensive to process on vacuum
filters or filter presses and further reduces sludge handling and disposal
costs.
Economic Evaluation
A cost comparison between the Molsons1 extended aeration and Deep Shaft demon-
stration plant is presented in Table 8. It is interesting to note that the
aeration costs for the Deep Shaft plant is 4.5 times less than the aeration
costs for the extended aeration plant. The cost of pH control is not includ-
ed since excess carbon dioxide from the brewery process is used for pH con-
trol on the basic side of 7.
The extended aeration does not include nutrient costs, but this is probably
offset by the fact that aerator usage may not be optimized.
354
-------
TABLE 8. MOLSONS1 DEEP SHAFT DEMONSTRATION PLANT
COST COMPARISON(6)
Component Deep Shaft Extended Aeration
($/l,000 kg BOD5) ($/l,000 kg BOD5)
Aeration1 7.51 35.64
Nutrients2 7.57 undefined
Digestion 5.83 undefined
20.91J 35.64
1 Based on 30.33 kW @ 1.6£AWh.
2 Based on $4.84/1,000 kg BOD5 ($2.20/1,000 Ibs BOD5) for
ammonia nitrogen and $2.73/1,000 kg BOD5 ($1.24/1,000 Ibs
BOD^) for phosphoric acid.
3 Relates to $1.80/1,000 m3 (26.2C/1,000 USG).
Full-Scale Deep Shaft Brewery Plant Cost Estimate
Table 9 describes the cost of a full-scale Deep Shaft plant designed on the
basis of the design information developed at the Molson's Deep Shaft demon-
stration plant.
The hypothetical plant is assumed to consist of screening, comminution, grit
removal, equalization, neutralization. Deep Shaft aeration, flotation, chemi-
cal addition, vacuum filtration and sludge disposal.
The Deep Shaft cost includes the installed cost of the aeration and solids
separation portion of the plant assuming all front-end components are essen-
tially equal for all biological systems. The Deep Shaft Process however, does
not require primary sedimentation in advance of it.
Table 10 and 11 offers a breakdown of energy and operating costs for the two
Deep Shaft options investigated. The roughing plant will, in fact, experience
a large degree of BOD^ removal but a large amount of solids would be slipped
to the sewer.
The total Deep Shaft costs estimated at 2.5 and 2.75 million dollars for
roughing and complete treatment are expected to represent 43 and 51% respec-
tively of the total plant capital costs. The Deep Shaft operating costs are
expected to represent 50% of the total operating cost as demonstrated in
Table 11.
355
-------
TABLE 9. DEEP SHAFT BREWERY APPLICATION COST EXAMPLES(6)
Parameter
Mean Flow
Peak Flow
Organic Loading
MLSS
Energy
(b)
Operating Cost
Cost/Flow
Deep Shaft Portion
Deep Shaft Cost
Deep Shaft Plant Area
Units
m3/hr.
m3/hr.
kg BODs/day
mg/1
kW
$/day
$/l,000 m3
% of total cost
$ million
m2
Duty
Roughing
(300/300)
636
700
14,545
8,000
224
704.05
1.24
43
2.5
743
Complete
(50/50)
636
700
14,545
8,000
242
1,107.76
1.85
51
2.75
743
TABLE 10. DEEP SHAFT BREWERY APPLICATION COST ESTIMATE
(a) Energy
Deep Shaft Aeration
Lighting
Scrapers
Sludge Pumps
Fans
Instruments
Duty
Roughing
(300/300)
191.00
6.75
4.50
15.00
7.00
0.75
Complete
(50/50)
210.00
6.75
4.50
15.00
7.00
0.75
TOTAL
225.00 kW
244.00 kW
356
-------
TABLE 11. DEEP SHAFT BREWERY APPLICATION COST EXAMPLE
(b) Operating Cost
(S/day)
Energy
Chemicals/Nutrients
Flotation Aids
Manpower
Sludge Handling
Sludge Disposal
TOTAL
Roughing
(300/300)
85.82
110.08
NIL
108.00
263.65
136.50
$704.05/day
Duty
Complete
(50/50)
93.02
110.08
256.00
108.00
356.16
184.50
$l,107.76/day
CONCLUSIONS
Eco has established the basic design parameters for full-scale brewery and
dairy Deep Shaft effluent treatment plants.
The subsequent costs of construction and operation can be accurately project-
ed for full-scale brewery and dairy Deep Shaft effluent treatment plants.
Full-scale Deep Shaft effluent treatment plants can now be built to treat
dairy and brewery effluent to municipal pretreatment levels of 200 mg/1 BOD^
and 200 mg/1 TSS and levels of 50 mg/1 BOD5 and 50 mg/1 TSS for direct dis-
charge .
Improvements in suspended solids separation should result in an ability to
meet 30 mg/1 TSS in the future.
The major advantages associated with utilizing the technology to treat food
processing wastewater include possible reductions in capital cost, lower
power costs and space economy.
The technology can be used in urban centres because it can be inexpensively
enclosed and is odorless and noiseless (ie. less than 85 db).
357
-------
BIBLIOGRAPHY
1. Bolton, D.H., Bouchard, J.P., and Hines, D.A. "The Application of the
ICI Deep Shaft Process to Industrial Effluents". 31st Annual Purdue
Industrial Waste Conference, 4-6 May 1976, La Fayette, Indiana, U.S.A.
2. Bradley, B.J. "The ICI Deep Shaft Effluent Treatment Process".
29th Annual Atlantic Canada Section, AWWA Meeting, 12-15 September 1976,
Halifax, Nova Scotia, Canada.
3. Bolton, D.H., and Ousby, J.L. "The ICI Deep Shaft Effluent Treatment
Process and its Potential for Large Sewage Works". Workshop on Large
Wastewater Treatment Plants, International Association on Water
Pollution Research, 8-12 September 1975, Vienna, Austria.
4. Chisholm, K.A., and Sandford, D.S. "The Treatment of Municipal Wastewater
Using the ICI Deep Shaft Process". 29th Annual Western Canada Water &
Sewage Treatment Conference, 28-30 September 1977, Edmonton, Alberta,
Canada.
5. Knudsen, F.B., Kuslikis, B.P., Pollock, D.C., and Wilson, M.A.
"Application of the Deep Shaft Process to the Treatment of Brewery
Effluents". Water, Wastewater Equipment Manufacturers Association
Conference, 11 April 1978, St. Louis, Missouri, U.S.A.
6. Knudsen, F.B. "Brewery Effluent Treatment by the ICI Deep Shaft Process".
Montreal Chapter of the ASBC, 17 March 1978, Montreal, P.Q., Canada.
358
-------
NINTH FOOD WASTE SYMPOSIUM
REGISTRATION LIST
I. L. ABERCROMBIE
Sweco Inc.
P.O. Box 4151
Los Angeles, CA 90051
WALTER ADAMS
Sterling Colorado Beef Co.
Box 1728
Sterling, CO 80751
MEL ALSAGER
J. R. Simplot
Box 27
Boise, ID 83707
HAROLD BARNETT
Nat'l. Marine Fisheries Service
2725 Montlake Blvd. E.
Seattle, WA 98112
EDWARD BARRERA
Ranch Style Inc.
Box 1867
Fort Worth, TX 76101
DONALD J. BAUMANN
Creighton University
2500 California Street
Omaha, NE 68131
MARTHA BEACH
N-CON Systems
308 Main Street
New Rochelle, NY 10801
RICHARD T. BEAUPRE
Capitol Consultants Inc.
1627 Lake Lansing Road
Lansing, MI 48912
BARRETT E. BENSON
U.S. EPA - NEIC
Bldg. 53, Denver Federal Center
Denver, CO 80225
EUGENE E. BERKAU
U.S. EPA, IPCD
Industrial Environmental Res. Lab.
Cincinnati, OH 45268
JAMES R. BOYDSTON
U.S. EPA, IPCD
200 S.W. 35th Street
Corvallis, OR 97330
G. M. BROOKS
Mississippi Cooperative Ext. Serv.
Food and Fiber Center
P.O. Box 5426
Mississippi State, MS 39762
W. E. BROOKS
Astro Met
Box 520
Wooster, OH 44691
WILLIAM BROTHERTON
International Co-op
P.O. Box 1378
Grand Forks, ND 58201
ROBERT 0. BROWN
Robert 0. Brown Co.
4200 Cedar Avenue South
Minneapolis, MN 55407
ROLF BROWN
Robert 0. Brown Co.
4200 Cedar Avenue South
Minneapolis, MN 55407
CLIFFORD BRUELL
Adolph Coors Company
Mail #203
Golden, CO 80401
JOHN R. BURGESON
M & I, Inc.
4710 South College
Fort Collins, CO 30521
359
-------
DONALD G. BZDYL
Envirotech Corporation
301 S. Hicks Road
Palatine, IL 60067
ALAN D. CARLSON
John Morrell & Co.
208 S. LaSalle Street
Chicago, IL 60604
ROBERT CASCIANO
Airco Industrial Gases
575 Mountain Avenue
Murray Hill, NJ 07974
SOT CHIMONAS
J. R. Simplot Co.
P.O. Box 1059
Caldwell, ID 83605
H. S. CHRISTIANSEN
Carnation
5045 Wilshire Boulevard
Los Angeles, CA 90036
0. A. CLEMENS
SESCO
1919 Swift Drive
Oakbrook, IL 60521
WALTON H. CRAIG
Sharpies-Stokes Division
Pennwalt Corporation
111 Windsor Drive
Oak Brook, IL 60521
DONALD DALTON
Valmac Industries
Box 842
Russellville, AR 78629
SATYENDRA M. DE
W. D. Byron & Sons, Inc.
Williamsport, MD 21795
C. ROY DEAN
MBPXL Corporation
P.O. Box 2519
Wichita, KS 67201
ROBERT DELONG
Jeno's Inc.
4125 Pipestone Road
Sodus, MI 48126
ROBERT E. DIEHL
Van Camp Sea Food Company
11555 Sorrento Valley Road
San Diego, CA 92121
SUSAN DOBBERSTEIN
Foremost Foods Co.
6363 Clark Avenue
Dublin, CA 94566
KENNETH A. DOSTAL
U.S. EPA, IERL
Food and Wood Products Branch
200 S.W. 35th Street
Corvallis, OR 97330
GARY DOWNING
Adolph Coors Company
Mail #703
Golden, CO 80401
CHARLES B. DULL
James Allan & Sons
P.O. Box 8329
Stockton, CA 95208
ROBERT E. DUNNICK
Hanover Brands, Inc.
P.O. Box 334
Hanover, PA 17331
JIM EISINGER
C & D Foods, Inc.
2319 Raymond Avenue
Franksville, WI 53126
THOMAS E. ELLIOTT
Swift & Company
115 W. Jackson Boulevard
Chicago, IL 60604
DAVID B. ERTZ
Edward C. Jordan Co., Inc.
P.O. Box 7050 Downtown Station
Portland, ME 04112
360
-------
LARRY A. ESVELT
Esvelt Environmental Engineering
East 7905 Heroy
Spokane, WA 99206
ANN E. FARRELL
J. M. Montgomery Consulting Engineers
1990 N. California Boulevard
Walnut Creek, CA 94596
R. THOMAS FITZGERALD
Furman Canning Co.
R. D. #2
Northumberland, PA 17857
E. L. FOERSTER, SR.
Consulting Engineer
Box 779
Harrisonburg, VA 22801
CLYDE W. FULTON
Stanley Associates Engineering Ltd.
505 - 5th Avenue S.E.
Calgary, Alberta T2G OE9
THOMAS M. FURLOW
Jordan, Jones & Goulding, Inc.
Suite 200, 2000 Clearview Ave., N.E.
Atlanta, GA 30340
TOM GALLO
Eco Research Ltd.
45 Sheppard Avenue E.
Willowdale, Ontario M2N 2Z9
CHARLES GOBLE
Levelland Vegetable Oil, Inc.
P.O. Drawer N
Levelland, TX 79336
HAROLD I. GOLDSMITH
Kraft, Inc.
801 Waukegan Road
Glenview, IL 60025
PAUL H. M. GUO
Environment Canada
1756 Old Waterdown Road
Burlington, Ontario L7R 4A6
C. FRED GURNHAM
Gurnham & Associates, Inc.
223 West Jackson Boulevard
Chicago, IL 60606
SUZAN A. GUTTORMSEN
Brown & Caldwell
100 W. Harrison
Seattle, WA 98119
CHARLES A. HAAS
Wells Engineers, Inc.
P.O. Box 177
Gering, NE 69341
DASEL E. HALLMARK
DSA, Inc.
2186 So. Holly
Denver, CO 80222
TOM HARDING
Mountaire Poultry,
123 W. Park
DeQueen, AR 71832
Inc.
J. M. HASKILL
Fisheries & Environment Canada
Water Poll. Control Directorate
Ottawa, Ontario K1A 1C8
KERRY D. HERD
Techna-Dyne
7204 So. Garfield
Littleton, CO 80122
J. C. HESLER
The Greyhound Corp. (Armour)
202 E. Voltaire
Phoenix, AZ 85022
JIM HETRICK
Combustion Engineering Bauer
P.O. Box 722
Dana Point, CA 92629
M. D. HIXSON
Sweco Inc.
6033 E. Bandini Blvd.
Los Angeles, CA 90051
361
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HOEFLER
Alwatech A/S
Harbitzalleen 3
Oslo 2, Norway
A. HOPWOOD
Alwatech UK
33 A. Park Parade
Hazlemere, Highwycombe UK
JOHN HORNBECKER
Fluid Systems Inc.
1777 So. Bellaire
Denver, CO 80222
H. C. 1SAKSEN
Alwatech A/S
Oslo, Norway
WILLIAM R. ISHERWOOD
Ponder Engineering & Survey
P.O. Box 236
Daphne, AL 36526
NABEEL L. JACOB
Nat'l. Food Processors Association
1950 Sixth Street
Berkeley, CA 94710
H. R. JAKUBIEC
Canada Packers Limited
95 St. Clair Avenue West
Toronto, Ontario M4V 1P2
C. J. JOST, JR.
Anheuser-Busch, Inc.
721 Pestalozzi, Bldg. 3
St. Louis, MO 63118
ROBERT M. KEDDINGTON
K & P Inc.
3331 So. 9th E., Suite 210
Salt Lake City, UT 84106
JOHN S. KEITH
Inmont Corporation
609 Lafayette Avenue
Hawthorne, NJ 07506
RALPH KENWORTHY
John Inglis Frozen Foods Company
300 Daly Avenue
Modesto, CA 95353
LLOYD H. KETCHUM, JR.
University of Notre Dame
Department of Civil Engineering
Notre Dame, IN 46556
STEPHEN E. KING
Union Carbide Corporation
17 Executive Park Dr., N.E.
Atlanta, GA 30351
WILLIAM KOPET
Carborundum Co.
132 Helen Way
Escondido, CA 92025
VACLAV KRESTA
Department of the Environment
P.O. Box 6000
Fredericton, New Brunswick
Canada
ED KROEKER
Stanley Associates Engrg. Ltd.
11748 Kingsway Avenue
Edmonton, Alberta T5G 0X5
KENNETH B. KYTE
Sharpies Stokes Division
Pennwalt Corporation
111 Windsor Drive
Oak Brook, IL 60521
KEN LACONDE
SCS Engineers
4014 Long Beach Boulevard
Long Beach, CA 90807
LARRY F. LAFLEUR
Domingue, Szabo & Assoc., Inc.
117 Calco Boulevard
Lafayette, IN 70505
C. P. LAND
Kahn's Company
3241 Spring Grove Avenue
Cincinnati, OH 45225
ROBERT C. LANDINE
ADI Limited
P.O. Box 44
Fredericton, N.B. E3B 4Y2
362
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PETER J. LANDWEHR
Oscar Mayer & Co.
Box 7188
Madison, WI 53707
PAUL F. LEAVITT
Gerber Products Co.
445 State Street
Fremont, MI 49412
K. V. LENSMEYER
Ralston Purina Co.
Checkerboard Square
St. Louis, MO 63188
HUDA S. LILLARD
USDA, SEA, Russell Research Center
P.O. Box 5677
Athens, GA 30604
ROBERT G. LISTER
American Can Company
American Lane
Greenwich, CT 06830
R. D. LONGE
American Stores Co.
200 S. 2nd
Lincoln, NE 68507
DUGAL R. MACGREGOR
Agriculture Canada
Research Station
Summerland, B.C. VOH 1ZO
R. B. MAGUIRE
Agripac Inc.
P.O. Box 5346
Salem, OR 97304
PAUL M. MARTIN
Victor F. Weaver, Inc.
403 S. Custer Avenue
New Holland, PA 17557
JAMES L. MASON
Wastewater Operator II
Wampler Foods, Inc.
Hinton, VA 22831
ROBERT E. MEANS
Bouillon, Christofferson and
Schairer
505 Washington Building
Seattle, WA 98101
VON T. MENDENHALL
Utah State University
Nutrition & Food Science Dept.
Logan, UT 84322
MIKE MEYER
C & D Foods, Inc.
2319 Raymond Avenue
Franksville, WI 53126
BYRON F. MILLER
Colorado State University
Department of Animal Sciences
Fort Collins, CO 80523
LARRY W. MILLER
Country Pride Foods Ltd.
P.O. Box 1997
El Dorado, AR 71730
JERRY D. MINOR
Kramer, Chin & Mayo
535 S.W. 4th
Corvallis, OR 97330
T. L. MCANINCH
Birko Chemical Corporation
P.O. Box 1315
Denver, CO 80201
GERALD N. MCDERMOTT
Procter & Gamble Co.
Hillcrest Tower
7162 Reading Road
Cincinnati, OH 45222
JOE H. MCGILBERRY
Mississippi Coop. Extension Serv.
Food and Fiber Center
P.O. Box 5426
MS State, MS 39762
363
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DAVID MCNAIR
Allied Mills Inc.
110 N. Wacker Drive
Chicago, IL 60606
JACK MCVAUGH
Envirex Inc.
1901 S. Prairie Avenue
Waukesha, WI 53186
CARL E. NALL
Pacific Egg and Poultry Association
9800 S. Sepulveda, Suite 618
Los Angeles, CA 90045
DAVID B. NELSON
Monsanto Research Corporation
1515 Nicholas Road
Dayton, OH 45407
PER NETTLI
Alwatech A/S
Oslo, Norway
STEPHEN NUTT
Dearborn Envir. Consulting Services
3451 Erindale Station Road
Mississauga, Ontario L5C 2S9
JAMES H. DATES
J. R. Simplot Co.
Box 1029
Caldwell, ID 83605
GUS ORTENGREN
Alwatech
1550 So. Pearl Street
Denver, CO 80210
GAYLORD M. PALMER
Foremost Foods Company
6363 Clark Avenue
Dublin, CA 94566
CLINTON E. PARKER
U.S. EPA, lERL-Ci
5555 Ridge Avenue
Cincinnati, OH 45268
JOHN P. PILNEY
MRI, North Star Division
10701 Red Circle Drive
Minnetonka, MN 55343
BRIAN W. RAINES
National Pet Food Corporation
P.O. Box 788
Long Beach, CA 90801
ERNEST R. RAMIREZ
Swift & Co.
1919 Swift Drive
Oak Brook, IL 60521
JAMES S. RAUH
Olin Water Services
51 Corporate Woods
9393 West 110th Street
Overland Park, KS 66210
MILTON D. REDICK
Capitol Consultants Inc.
1627 Lake Lansing Road
Lansing, MI 48912
ROBERT RENNER
M & I, Inc.
4710 South College
Fort Collins, CO 80521
JO ANN ROBISON
Boise Cascade
Box 851
Stanfield, OR 97875
CARL T. ROLLINS
DuBois
3630 E. Kemper Road
Sharonville, OH 45241
WALTER W. ROSE
Nat'l. Food Processors Assoc.
1950 Sixth Street
Berkeley, CA 94710
JOHN ROSENAU
Dept. of Food & Agric. Engrg.
University of Massachusetts
Amherst, MA 01003
364
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D. S. SANDFOKD
Eco Research Limited
6940 Fisher Road, S.E.
Calgary, Alberta T2H OW3
NEIL SCHACHT
Con Agra Poultry
P.O. Box 2084
Decatur, AL 35602
CARL SCHAFER
U.S. EPA, IEPD
401 M Street, SW
Washington, DC 20460
LANNY A. SCHMID
Spencer Foods Inc.
Box 544
Schuyler, NE 68661
CURTIS SCHMIDT
SCS Engineers
4014 Long Beach Boulevard
Long Beach, CA 90807
MARTIN D. SCHWARTZ
Arthur G. McKee
10 So. Riverside Plaza
Chicago, IL 60606
KHEM SHAHANI
Department of Food Science
University of Nebraska
Lincoln, NE 68583
RONALD D. SCINOCCA
Jeno's Inc.
525 Lake Avenue So.
Duluth, MN 55801
ROBERT J. SHERMAN
Alwatech Division
A. L. Laboratories, Inc.
452 Hudson Terrace
Englewood Cliffs, NJ 07632
JOSEPH SILVIA
Envirex Inc.
1901 S. Prairie Avenue
Waukesha, WI 53186
K. LYNN SIRRINE
The R. T. French Co.
434 So. Emerson
Shelley, ID 83274
NORMAN J. SMALLWOOD
Lou Ana Foods, Inc.
P.O. Box 591
Opelousas, LA 70570
JOHN SMOLIK
Corning Glass Works
Corning, NY 14830
STEVEN M. SPANGLER
Van Camp Sea Food Company
11555 Sorrento Valley Road
San Diego, CA 92121
J. H. STANFIELD
Alpha Research & Technology
3955 B Newport Street
Denver,.CO 80207
ROBERT M. STEIN
AWARE Inc.
Box 40284
Nashville, TN 37204
PAUL STEPHENSON
Morrison, Cooper & Partners
P.O. Box 6214
Wellington, New Zealand
RICHARD W. STERNBERG
U.S. EPA
401 M Street, SW
Washington, DC 20460
DALE W. STORM
Illinois Water Treatment Co.
4669 Shepherd Trail
Rockford, IL 61105
A. J. SZABO
Domingue, Szabo & Assoc., Inc.
P.O. Box 52115
Lafayette, LA 70505
365
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DONALD J. THIMSEN
General Mills, Inc.
P.O. Box 1113
Minneapolis, MN 55440
HAROLD W. THOMPSON
U.S. EPA, IERL
Food and Wood Products Branch
200 S.W. 35th Street
Corvallis, OR 97330
STEVE THURLOW
Stephen Thurlow Company, Inc.
P.O. Box 9520
Seattle, WA 98109
JON TIENSTRA
Allen Products Company, Inc.
P.O. Box 2187
Allentown, PA 18801
CALVIN R. TININENKO
Farmland Foods, Inc.
P.O. Box 7527, Dept. 222
Kansas City, MO 64116
E. TONSETH
Alwatech
1550 So. Pearl Street
Denver, CO 80210
ALAN TUROVER
Castle & Cooke Co.
5th & Virginia
San Jose, CA 95112
STEVEN L. TYLER
A. E. Staley Mfg. Co.
Box 432
Monte Vista, CO 81144
RICHARD V. VANCE
Anheuser-Busch, Inc.
721 Pestalozzi Street
St.. Louis, MO 63118
R. H. VICKERMAN
P.O. Box 261
Hardisty, Alberta TOB 1VO
V. H. VODRA
Birko Chemical Corporation
P.O. Box 1315
Denver, CO 80201
JOHN F. H. WALKER
Arthur G. McKee & Co.
10 S. Riverside Plaza
Chicago, IL 60606
GENE WALRATH
C & D Foods, Inc.
2319 Raymond Avenue
Franksville, WI 53126
J. C. WEISEL
Hydroscience, Inc.
2815 Mitchell Drive, Suite 124
Walnut Creek, CA 94598
W. JAMES WELLS, JR.
Wells Engineers, Inc.
515 North 87th Street
Omaha, NE 68114
ROGER WILKOWSKE
USDA, Extension
Science and Education Admin.
Washington, DC 20250
H. KIRK WILLARD
U.S. EPA, IERL
Food and Wood Products Branch
Cincinnati, OH 45268
LARRY WILLIAMS
Holly Farms of Texas Inc.
P.O. Box 789
Center, TX 75945
FELON R. WILSON
Domingue, Szabo & Associates
117 Calco Boulevard
Lafayette, LA 70505
MIKE WINTER
Wemco Division, Envirotech
Box 15619
Sacramento, CA 95608
366
-------
SHELLEY WIRSIG
Adolph Coors Co.
Department 300
Golden, CO 80401
JACK L. WITHEROW
U.S. EPA, IERL
Food and Wood Products Branch
200 S.W. 35th Street
Corvallis, OR 97330
PING-YI YANG
University of Hawaii
3050 Maile Way
Honolulu, HI 96822
WILLIAM D. RUTZ
MAPCO Inc.
Process & Pollution Controls Div.
1800 South Baltimore Avenue
Tulsa, OK 74119
367
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-78-188
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
PROCEEDINGS NINTH NATIONAL SYMPOSIUM ON FOOD
PROCESSING WASTES— March 29 - 31, 1978,
Denver, Colorado
5. REPORT DATE
August 1978 Issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Food and Wood Products Branch
Industrial Environmental Research Laboratory
Corvallis, Oregon 97330
10. PROGRAM ELEMENT NO.
1BB610
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
. Industrial Environmental Research Lab-Cinci, OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
13. TYPE OF REPORT AND PERIOD COVERED
"i nm PTr»r*^p*HT n gg
14. SPONSORING AGENCY CODE
EPA/600/12
15. SUPPLEMENTARY NOTES Additional sponsors include: National Food Processors Association,
American Meat Institute, Southeastern Poultry and Egg Association, Western States
Meat Packers Association, Pacific Egg and Poultry Association, and American Society
16. ABSTRACT Of Agricultural Engineers.
The Proceedings contains copies of the 24 papers presented at the Ninth National
Symposium on Food Processing Wastes. Subjects included: processing modifications,
product and by-product recovery, wastewater treatment, water recycle and water
reuse for several segments of the food processing industry. These segments
included: red meat and poultry, seafood, dairy, fruit, and vegetable.
Attendance at the two and one-half- day Symposium was approximately 170 with good
representation by industry, universities, consulting firms, as well as state and
Federal agencies.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COS AT I Field/Group
Industrial Wastes, Waste Water, Food
Processing, Byproducts
Process Modifications,
Water Reuse, Water
Recycle
13/B
18. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
374
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
368
ft U.S. GOVERNMBII PRINTING OFFICE: 1978—657-060/1496
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