United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Cincinnati OH 45268
EPA 600/2-79-030
January 1979
Research and Development
&EPA
Oxidation Ditch
Treatment of
Meatpacking Wastes
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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 fac litate 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 Servi.ce, Springfield, Virginia 22161.
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EPA-600/2-79-030
January 1979
OXIDATION DITCH TREATMENT OF MEATPACKING WASTES
by
Wayne L. Paulson
Lawrence D. Lively
John Morrell and Company
Chicago, Illinois 60604
Grant No. 12060 HUB
Project Officer
Jack L. Witherow
Food and Wood Products Branch
Industrial Environmental Research Laboratory
Cincinnati, Ohio 45268
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
control methods be used. The Industrial Environmental Research Laboratory -
Cincinnati (lERL-Ci) assists in developing and demonstrating new and improved
methodologies that will meet these needs both efficiently and economically.
This report presents design, modification, and evaluation of a channel
aeration activated sludge wastewater treatment plant, which treated 2.8
million gallons per day of wastewater from a large meatpacking operation.
Design engineers and managers of industrial plants discharging wastewaters
with high concentrations of organic pollutants will find the report valuable
when selecting, designing, and operating an activated sludge treatment
process. Further information on the subject can be obtained by contacting
the Food and Wood Products Branch, Industrial Environmental Research Labora-
tory-Cincinnati.
David G. Stephan
Director
Industrial Environmental Research Laboratory
Cincinnati
iii
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ABSTRACT
The analysis of 18 months of operation for a channel aeration activated
sludge wastewater treatment plant is presented. The treatment plan receives
an average flow of 2.8 million gallons per day from the John Morrell and
Company, Ottumwa, Iowa, hog and beef meatpacking plant. The treatment plant
includes pre-aeration, primary settling, and grease removal followed by two
3.5-million gallon aeration channels (40 by 6 feet deep by 1,050 feet in
length) in parallel. Rotor and floating aerators are utilized. One channel
utilizes an experimental straightline settling unit (16 by 475 by 6 feet
deep). The other uses a rim-flow 58 feet in diameter circular settling unit.
The design and operation of the primary treatment units were inadequate,
especially the tubular conveyors used for sludge removal. More efficient
grease and suspended solids removal are needed before the aeration process.
The channel aeration activated sludge process is capable of achieving BOD
removal of 90 to 95 percent from meatpacking wastewater. High effluent
ammonia levels (approximately 20 milligrams per liter) are of concern.
Various design changes are needed to improve the consistency of high effluent
quality.
Dewatered waste-activated sludge from meatpacking waste treatment has
potential as an animal feed supplement.
This report was submitted in fulfillment of Project No. 12060 HUB by the
John Morrell and Company under the partial sponsorhip of the US Environmental
Protection Agency. The report covers the period December 1966 to July 1972,
and work was completed as of July 1972.
IV
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CONTENTS
Foreword
Abstract iv
Figures vi
Tables ix
Conversion Factors xi
Acknowledgments xii
1. Introduction 1
Scope and background 1
Design Approach 1
2. Conclusions 4
3. Recommendations 6
4. Process Description 7
Flow pattern 7
Primary units 7
Secondary units 12
5. Operational Experience - Mechanical 14
Plant interrelationships 14
Primary units - aeration, flotation, settling 14
Aeration channels 15
Straightline settling unit 16
6. Process Evaluation 18
Project objectives 18
Sampling and analytical program 18
Wastewater characteristics 19
7. Primary Treatment Performance 23
Removal of organics and solids 23
Solids and grease disposal 29
Pilot plant study - dissolved air flotation 30
8. Secondary Treatment Performance 32
East channel (I) - circular settler 32
West channel (II) - Straightline settler 46
Aeration system analysis 59
9. Financial Considerations 61
Construction costs 61
Operation and maintenance costs 61
Total annual costs 61
10. Waste Activated Sludge Utilization 65
Characteristics and treatment 65
Animal feed supplement 65
11. Effluent Chlorination 72
12. Pertinent Publications 74
Appendices 75
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FIGURES
Number Page
1 Typical wastewater flows 8
2 Schematic flow diagram 9
3 Wastewater treatment system 10
4 Live weight kill versus date 21
5 Total flow versus date 22
6 Percent removal suspended solids (primary) versus flow 26
7 Percent removal grease (primary) versus flow 27
8 Percent removal BOD (primary) versus flow 28
9 East channel flow versus date 34
10 East channel dissolved oxygen versus date 35
11 East channel temperature versus date 36
12 East channel MLSS versus date 37
13 Sludge volume index versus date (east) 41
14 Sludge volume index versus effluent suspended solids (east) . . 42
15 Flow rate versus effluent suspended solids (east) 43
16 Volumetric loading versus percent removal BOD (east) 44
17 Loading factor versus percent removal BOD (east) 45
18 West channel flow versus date 48
19 West channel dissolved oxygen versus date . 49
20 West channel MLSS versus date 50
21 Sludge volume index versus date (west) 53
vi
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Figures (continued)
Number Page
22 Sludge volume index versus effluent suspended solids (west) . . 54
23 Flow rate versus effluent suspended solids (west) 56
24 Volumetric loading versus removal BOD (west) 57
25 Loading factor versus percent removal BOD (west) 58
A-l Pounds suspended solids/live weight killed versus date (raw) . . 75
A-2 Raw total suspended solids versus primary effluent total
suspended solids 76
A-3 Percent removal suspended solids versus date (primary) 77
A-4 Raw grease versus primary effluent grease 78
A-5 Raw BOD versus primary effluent BOD 79
B-l East effluent suspended solids versus date 80
B-2 East effluent pounds suspended solids/live weight killed versus
date 81
B-3 East effluent BOD total versus date 82
B-4 East effluent pounds BOD total/live weight killed versus date . 83
C-l West effluent suspended solids versus date 84
C-2 West effluent pounds suspended solids/live weight killed versus
date 85
C-3 West effluent BOD total versus date 86
C-4 West effluent pounds BOD total/live weight killed versus date . 87
D-l Plant site location 88
D-2 Aerial view of treatment system in construction 89
D-3 Treatment plant 90
D-4 Heating unit modification to tubular conveyor system ...,,. 91
D-5 Pre-aeration primary unit and composite sampler 92
D-6 Tubular conveyors in primary system 93
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Figures (continued)
Number Page
D-7 Grease wagons and solids disposal carts 94
D-8 Rotor and floating aerators in west channel 95
D-9 Fifty-horsepower floating aerator 96
D-10 Drum failure of 50-horsepower floating aerator 97
D-ll Typical blades of rotor aerator 98
D-12 Close-up of rotor aerator operation - east channel 99
D-13 Icing problems with rotor aerators and walkway 100
D-14 Initial flat shield design for icing conditions 101
D-15 Icing problems and motor covers - rotor aerators 102
D-16 Curved shield system to minimize icing 103
D-17 Inlet and sludge collector area for straightline settler .... 104
D-18 Side inlet port to straightline settler 105
D-19 Straightline settler and cage rotor - drained 106
D-20 Straightline settler in operation 107
D-21 Effluent weir for straightline settler 108
D-22 Turbulence and flushing door location - straightline settler . . 109
D-23 Circular settling unit - east channel 110
viii
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TABLES
Number Page
1 Plant Features 11
2 Detention Time and Overflow Rate 16
3 Characteristics of Wastewater Flow 20
4 Performance of Primary Units 24
5 Settling Unit Detention Time and Overflow Rate 24
6 Primary Effluent Characteristics 25
7 Grit Quantities and Characteristics 29
8 Primary Sludge Characteristics 30
9 Performance of DAF Unit 31
10 Operational Characteristics - East Aeration Channel (I) 33
11 Final Effluent Characteristics - East Aeration Channel (I) ... 38
12 Performance of Secondary Units - East Channel (I) 39
13 Circular Clarifier Detention Time and Overflow Rate 40
14 Operational Characteristics - West Aeration Channel (II) .... 47
15 Final Effluent Characteristics - West Aeration Channel (II) ... 51
16 Performance of Secondary Units - West Channel (II) 52
17 Detention Time and Overflow Rate for Straightline Settler .... 55
18 Construction and Equipment Costs 62
19 Operation and Maintenance Costs - 1971 63
20 Power Requirements 63
21 Treatment Costs 64
ix
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Tables (continued)
Number Page
22 Basket Centrifugation of Waste Activated Sludge 66
23 Composition of Waste Activated Sludge 67
24 Protein Evaluation Tests 68
25 Composition of Sludge 68
26 Rat Feeding Test 70
27 Amino Acid Analysis of Activated Sludge 71
28 Typical Coliform Results 72
29 Final Effluent Chlorination 73
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To convert from
Degree Celsius (°c)
Cubic Feet
Foot
CONVERSION FACTORS AND METRIC PREFIXES3
CONVERSION FACTORS
To
Degree Fahrenheit
Metre3
Metre
Square feet
3
Feet /min
Gallon
Ga 1 1 on/day
Horsepower
Inch
Metre J
Metre /sec
Metre3
3
Metre /sec
Watt
Metre
Multiply by _
t° = 1.8 t£ + 32
2.831 x 10"2
3.048 x 10"1
9.290 x 10"4
4.719 x 10"4
3.785 x 10"3
4.381 x 10"8
Pounds
Ki 1ograms
7,457 x
2.540 x 10
4.535 x 10"
-2
Prefix
Symbol
METRIC PREFIXES
Multiplication factor
Example
Giga
Kilo
Mega
Milli
G
k
M
m
103
10fi
10 3
10'3
1 GJ -
1 kg -
1 MJ =
1 mm =
1 x 10? joules
1 x 10g grams
1 x 10 q joules
1 x 10"° meter
Standard for Metric Practice. ANSI/ASTM Designation: E 380-76 , IEE std
268-1976, American Society for Testing and Materials, Philadelphia, Penn-
sylvania, February 1976. 37 pp.
XI
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ACKNOWLEDGMENTS
During the course of this project, many individuals contributed to its
successful completion.
Dr. H. 0. Halverson conceived the original application of the process to
treatment of meatpacking wastes. His concepts were further developed by Mr.
George Ahrens, John Morrell Project Engineer, with assistance from the
Mechanical Engineering Department of John Morrell and Company and US
Environmental Protection Agency engineers.
Mr. Darwin Kueck performed admirably as Project Director through the
trying times of start-up to the research demonstration phase. His close
attention to solution of mechanical difficulties and coordination of in-plant
waste management is particularly noteworthy. Mr. Anthony Grenis and Mr. Paul
Lange performed the chemical analysis required for the project study.
Special recognition is tendered Dr. William E. Kramlich, Vice President
and Director of Research, John Morrell and Company, for his direction,
encouragement, and resourcefulness.
The assistance and encouragement of Mr. Perry Martin, Plant Manager; Mr.
Mike Link, Operations Manager; and Mr. John Logan, Master Mechanic was
imperative to success of the project.
Special accolades are due Mrs. Carolyn Pierce for clerical, secretarial,
and procurement support. Without the dedication and resourcefulness of Mr.
Dale Wilson, Chief Operator of the Treatment Plant, completion of the project
would have been prolonged. Recognition is also given Mr. Dale Baker, Plant
Operator, for superior services.
Appreciation is extended to Mr. L. D. McMullen, University of Iowa, for
providing computer analysis of the data and to Mrs. Lois Will for assistance
in processing the data and preparation of the final report.
The support of the project by the Office of Research and Development, US
Environmental Protection Agency is gratefully acknowledged. Particular
appreciation is extended to Mr. Jack L. Witherow, Food and Wood Products
Branch, Industrial Environmental Research Laboratory, Cincinnati and Mr. George
Keeler, US Environmental Protection Agency, Washington, DC.
XII
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SECTION 1
INTRODUCTION
SCOPE AND BACKGROUND
The primary objective of this demonstration project was to determine the
maximum effectiveness of the channel aeration activated sludge process in
achieving biochemical oxygen demand (BOD) and nitrogen removal from packing-
house wastewater. The project included design, construction, and operational
phases. Additional objectives of the project were evaluation of the primary
treatment unit performance and utilization of waste activated sludge as an
animal feed supplement.
The project was located at the John Worrell and Company meatpacking plant
in Ottumwa, Iowa. Morrell and Company located meatpacking operations in
Ottumwa in 1887. The plant was nearly destroyed by fire in 1893. In the
early 1900's, the facilities were rebuilt and expanded. Several of the
buildings currently in use date back to this period. During the study period
the plant employed approximately 2,600 people. The average daily live weight
processed is 2 million pounds. This plant processes 6,500 to 7,000 hogs and
1,000 to 1,100 cattle per day in a one-shift operation, normally 5 days per
week.
The plant is located in south central Iowa near the Des Moines River.
This river basin drains central Iowa. A flood control reservoir (Redrock),
upstream from Ottumwa, completed in 1969 is to provide a minimum stream flow
of 300 cubic feet per second. River surveys were conducted by the State,
Morrell personnel, and consultants in the 1940's. As a result of these
findings, several in-plant control measures were begun in order to improve the
quality of waste discharges. These measures and others were instituted during
the 1950's and early 1960's. Daily losses of BOD, protein, and grease in
pounds per 1,000 pounds of live weight were reduced from 35 to 15, 18 to 8,
and 20 to 6, respectively. Some of the measures utilized to achieve this
change are dry rendering, dry removal of beef paunch, installation of catch
basins, and various separation and housekeeping techniques.
In 1966, the State of Iowa conducted a study of conditions in the Des
Moines River and waste contributions from the Ottumwa area. Based on
established Iowa water quality criteria for the Des Moines River downstream
from Ottumwa, the State set an allowable BOD discharge for treated wastewater
effluent from Morrell and Company of 2,200 pounds per day (see Figure D-l).
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During 1966-1977, in-plant waste surveys were conducted at Morrell to
determine the wastewater quantities and characteristics for treatment plant
design. It was determined that from 3.25 to 3.50 million gallons of waste-
water per day would require treatment. The daily (5-day week) BOD loading was
predicted to be 38,000 pounds. Based on a flow rate of 3.25 to 3,50 million
gallons per day, effluent quality (BOD) would have to be between 75 and 80
milligrams per liter. The overall treatment plant efficiency (BOD) required
would be approximately 95 percent.
DESIGN APPROACH
Dr. H. 0. Halvorson, consultant to Morrell, and the Morrell engineering
and research staff investigated several meatpacking waste treatment methods
that might be applied at Ottumwa. Dr. Halvorson recommended that the
oxidation ditch activated sludge process be investigated for the Morrell
plant. This process (known also as the Pasveer process) has been utilized
extensively in western Europe in the 1950's and 1960's. More than 100 such
plants have been installed in the United States and Canada.
Dr. Halvorson had observed the oxidation ditch process in Europe and had
worked on similar plants in the United States. He also cited a study by F,
Guillaume (Evaulation of the Oxidation Ditch as a Means of Wastewater
Treatment in Ontario. Ontario Water Resources Commission. July 1964).
Guillaume had concluded that "on the basis of the acquired information, that
the oxidation ditch treatment system is rather inexpensive to construct and
simple to operate, and that it produces an acceptable effluent consistently."
This conclusion was made with small municipalities in mind as he further
observed that an upper limit in size for which the oxidation ditch would still
be preferable was not known.
Municipal oxidation ditch plant performance at Glenwood, Minnesota, and
pilot plant studies on meatpacking wastes at Arkansas City, Kansas (Halvorson,
H. V., et al. Report - Proposed Packinghouse Waste Treatment Plant Employing
a Channel Aeration Process. John Morrell and Company. 1967), were used to
provide design information. Overall BOD reductions from 61 to 92 percent were
obtained at Arkansas City, with detention times from 8 to 48 hours and BOD
loadings from 8 to 65,cubic feet of ditch per pound of BOD. Dr. Halvorson
recommended a minimum detention time of 24 hours with a maximum BOD loading of
1 pound of BOD per 30 cubic feet of channel (33 pounds per 1,000 cubic feet).
Additional design criteria were proposed based in part on the above plants. A
federal research and demonstration grant was then obtained to partially
support the project.
The original plant design by Halvorson, et al., was not approved
initially by State officials. Various modifications were necessary prior to
approval of plans for construction. The final plant design was developed by
Mr. George E. Ahrens, Engineer and initial Project Director for Morrell and
Company at Ottumwa, with the assistance and approval of Morrell and Company
engineering staff and US Environmental Protection Agency research staff. The
details of the plant design will be presented in a subsequent section.
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Project bids were received in September 1968. The total plant cost was
estimated at $780,000. Wastewater flow was first accepted in November 1969.
Major mechanical and other plant start up difficulties developed and continued
until the fall of 1970. The major portion of the process evaluation was
conducted from January 1971 through June 1972.
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SECTION 2
CONCLUSIONS
1. The channel aeration activated sludge process is capable of achieving BOD
removal of 90 to 95 percent from meatpacking wastewater. High effluent
ammonia levels (approximately 20 milligrams per liter as nitrogen) are of
concern however.
Given the solid-liquid separation problems and the aeration
limitations, the overall treatment plant removal (untreated versus total
east effluent) was 95.7 percent (BODs), 84.6 percent (suspended solids),
and 96.3 percent for grease.
2. In order to achieve a more consistent effluent quality, improvements in
pre-treatment, aeration capacity and final sedimentation are needed.
3. The peak flow to the treatment plant was normally sustained for approxi-
mately 12 hours each day with a peak to average flow rate ratio of 1.2:1.
4. The design and operation of the primary treatment units were inadequate.
More efficient grease and suspended solids removal is needed prior to the
aeration process. Primary treatment modifications could significantly
increase the sludge collected and increase the potential for its use in a
by-product.
5. Tubular conveyors of the size used in the primary treatment system are
not satisfactory as sludge removal mechanisms for this type of
application.
6. Protection and proper location of the walkways and mechanical equipment,
i.e., rotor aerators, are necessary in northern climates to minimize
icing problems.
7. The aeration capacity was insufficient to obtain nitrification. Ammonia
concentrations were usually increased through the channel aeration
activated sludge process. This increase was also significantly affected
by the anaerobic sludge conditions in the primary treatment unit.
8. The mixed liquor suspended solids (MLSS) level was also limited by
aeration capacity. Oxygen deficiencies and odor problems were observed
at the higher levels of MLSS concentration.
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9. The effluent suspended solids variations did not correlate with flow to
the circular clarifier. The variations were largely due to the settling
properties of the suspension.
10. The concept of utilizing an available interior channel has merit, however
the performance of the unit was not successful because of the design of
the inlet, outlet and sludge collection system in the channel.
11. Air flotation followed by centrifugation is a satisfactory method for
concentration of the waste activated sludge. High recoveries and very
high cake concentrations were achieved via centrifugation of settled
waste activated sludge without the use of chemicals.
12. Dewatered waste activated sludge from meatpacking wastewater treatment
has potential as an animal feed suplement.
13. A chlorine dosage in excess of 10 milligrams per liter and a contact time
of approximately 15 minutes will achieve greater than 99 percent fecal
coliform reductions. In practically all cases the chlorinated final
effluent fecal coliform count was less than or equal to 10 organisms per
100 milliliters.
14. Total wastewater treatment costs for this treatment system, including
estimated costs for solids disposal, would be approximately 2 cents per
pound of BOD applied (33 tents per 1,000 pounds live weight killed, LWK).
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SECTION 3
REOMffiNMTIONS
1. More efficient and consistent pre-treatment is needed for successful
operation of the oxidation ditch activated sludge process for meat
packing wastewater treatment.
Consideration should be given to pressure air flotation or anaerobic
systems as pre-treatment units.
2. In order to utilize the design concept of the straightline settling unit,
improvements in the hydraulic design and solids removal features are
needed.
3. More flexibility and capacity should be incorporated in aeration system
design of this nature. The aeration system should have the ability to be
operated to meet the daily load variations as well as adjust to non-
production periods.
4. The potential of recovery of waste activated sludge for use as an animal
feel supplement warrants further study.
5. The nitrogen balance aspects of meatpacking waste treatment needs careful
study but this objective could not be fully accomplished in this
investigation. The aeration capacity was not sufficient to obtain
nitrification.
6. The evaluation of the potential for nitrification and possible
denitrification in an oxidation ditch process should be undertaken at
pilot scale to establish economic and technical feasibility.
7. Caution is required in experimenting with new equipment and process
design at full scale without some prior developmental or pilot
investigations. Experimentation with equipment should not be at the
expense of affecting the intended process evaluation. Additional unit
capacity to permit the experimentation without affecting the process
study should be incorporated into the project.
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SECTION 4
PROCESS DESCRIPTION
FLOW PATTERN
Initially, the wastewater treatment plant received flow from the hog and
beef kill in-plant catch basins. Sanitary wastewater and condenser water is
discharged to a separate 48-inch sewer line that is not normally tributary to
the treatment plant. Some additional plant flow such as from the stockyard
area and dehairing operations were added to the plant flow during the project.
The meatpacking operations are normally on a 5-day week one-shift schedule.
Typical weekday and weekend flow patterns are shown in Figure 1.
A schematic flow diagram of the plant design is shown in Figure 2. A
plant drawing and unit listing is presented in Figure 3. A description of the
plant features is shown in Table 1 (also see Figure D-2).
PRIMARY UNITS
The bar screen is hand-cleaned and receives the total gravity flow from
the processing operations before it is pumped to the treatment units.
Constant and variable speed pumps are used to match the in-flow to the
treatment plant.
The aeration compartment is intended to serve the dual purpose of grit
separation and aiding in grease separation. At design flow rate (3.25 million
gallons per day), the aeration compartment provides a 12-minute contact time.
The raw or untreated composite wastewater sample is taken at this point. The
settling compartment or catch basin provides a 42-minute detention time at
design flow. Tubular conveyors were installed to remove settleable solids and
grit, and this is believed to be the first installation of this type.
Collector flights convey the floated grease to the discharge end of the basin.
An overhead skimmer moves the grease into a trough equipped with a screw auger
for disposal to a grease hauling unit (see Figure D-5).
Primary sludge and grit is collected in 60-gallon dump carts and conveyed
to a landfill for disposal. Grease is collected in trailer-mounted 2,000-
gallon tanks for transport to the rendering department.
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2,800
oo
2,400
1,800
1,600
1,200
800
400
12
4am 8 12 4pm
HOURS OF THE DAY
Figure 1. Typical wastewater flows.
WEEKDAY - 2.80 MGD
WEEKEND - 0.67 MGD
12
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RETURN
WASTEWATER---CHOG AND CATTLE KILL,
MISCELLANEOUS PROCESS WATERS)
SCREENING -
GRIT f
SOLIDS <-
GREASE <-
SCREENING
AERATION
SETTLING AND
FLOTATION
12 ROTORS
2 20-HP
1 50-HP
WASTE
SLUDGE
(WEST)
AERATION
CHANNELS
RETURN
f ___ ^imr
12 ROTORS
2 20-HP
1 50-HP
(EAST)
FINAL SETTLING
TANKS
WASTE
SLUDGE
)= PARSHALL FLUMES
TO DES MOINES RIVER
Figure 2. Schematic flow diagram.
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INFLUENT
A = Screen
B = Pumping and Laboratory
C = Aeration
D = Settling
E = Flow Measurement
Sampling
F = Primary Effluent
Distribution Trough
G = Floating Aerators
H = Rotors
J = Final Settling
(East Channel)
K = Straight Line
Settling
L = Overflow Weirs
M = Effluent Chamber
(Measurement Sampling)
Figure 3. Wastewater treatment system.
10
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TABLE 1. PLANT FEATURES
Item
Description
Bar screen
Aeration compartment
Settling compartment
(Grease flotation)
Aeration channels*
Straightline settling unit
Circular settling unit
Aeration equipment
Flow measurement
Composite samplers
1.4 inch openings (size: 3' x 4')
21' x 20' x 9' (28,000 gallons)
Air supply: 150 cubic feet per minute
20' x 100' x 6V (97,000 gallons)
40' wide; 6' water depth
Length (N-S; st. line): 1,050'
Volume (each channel): 3,500,000 gallons
16' x 475' x 6' (342,000 gallons)
Area: 7,600 square feet
58' diameter; 9' depth (178,000 gallons)
Area (rim-flow): 2,640 square feet
East channel: 12 mini-magna rotors
27V diameter; 15' length
West channel: 12 magna rotors
42" diameter; 15' length
Each channel: 2-20-horsepower and
1 50-horsepower floating
aerators
Parshall flumes and primary effluent:
settled effluent from each channel
Plant influent and primary effluent:
settled effluent from each channel
*Guillaume, F. Evaluation of the Oxidation Ditch as a Means Wastewater
Treatment in Ontario. Ontario Water Resources Commission, July 1964.
11
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SECONDARY UNITS
The total primary effluent flow passes through an 18-inch Parshall flume
and is divided to flow in the relative amounts desired to each aeration
channel. The primary effluent composite sample is taken as this point.
The influent to each channel is introduced at two points 225 feet from
the north end of each channel (see Figure 3). The north-south channel length
is approximately 1,050 feet. Return sludge combines with the influent flow to
the east aeration channel at point E in Figure 3, In the west aeration
channel, return sludge is pumped into the channel near point A (Figure 3). In
addition, some of the solids settled out in the straightline settling unit (K
in Figure 3) are re-suspended and directed into the aeration channel through
common wall openings at the north end of unit K in Figure 3.
The mixed liquor from the east aeration channel discharges to an overflow
weir trough (L) located in the channel and flows to a 58-foot diameter
circular clarifier (J). The effluent from the circular unit flows to building
M (Figure 3) where the flow rate is determined and a composite sample is
taken. The flow then combines with the flow from the west aeration channel
and flows to the Des Moines River. Chlorination disinfection can be conducted
at this location. The settled solids are pumped to point E (Figure 3) where
they are combined with the channel influent as return sludge. If sludge is to
be wasted, it is pumped to a wet well at point A.
The mixed liquor from the west aeration channel was designed to flow
through ports at the north curved end of the channel into the straightline
settling unit (K). An effluent overflow weir trough is located at the south
end (L) of the 475-foot long settling unit. The unit is 16 feet wide and 6
feet deep. The clarified effluent flows to building M where the flow is
recorded and a composite sample is taken.
A 15-foot cage rotor was provided to prevent the accumulation of settled
sludge solids beyond the 44-foot collector flight path which terminated north
of the rotor in the straightline. The sludge hopper is at the north end of
the unit. Sludge can be wasted from this hopper similar to the procedure for
the waste sludge from the circular unit. Return sludge is as noted above.
The east aeration channel is equipped with 12 mini-magna rotors
(Lakeside), 27.5 inches in diameter and 15 feet in length each. The rotors
are normally operated at 93 revolutions per minute and can be immersed up to
10.5 inches as installed in this channel. Performance test data was not
available for this modified rotor design at the time of the study.
The west aeration channel has 12 42-inch diameter magna rotors (Lakeside)
with a total rotor length of 180 feet. These units are normally operated at
68 revolutions per minute and can be immersed up to 10.5 inches.
For normal conditions, the units are rated at 4.8 pounds of oxygen per
hour per foot of rotor at zero dissolved oxygen in tapwater (at 20 degrees
Celsius, C). The rotors also provide the velocity to maintain the solids in
suspension.
12
-------
In addition, each channel has one 50-horsepower and two 20-horsepower
flotating aerators (Richards). The 20-horsepower units are each rated (by the
manufacturer) at 1,400 pounds of oxygen per day and the 50-horsepower unit at
3,000 pounds of oxygen per day. Both ratings are at zero dissolved oxygen and
in tapwater (at 20 degrees C). It should be noted that this application is
not in accordance with normal installation practice for these aerators.
13
-------
SECTION 5
OPERATIONAL EXPERIENCE - MECHANICAL
PLANT INTERRELATIONSHIPS
During the early months of operation, work continued in the processing
area on connections to the wastewater treatment plant. Additional in-plant
control measures were being developed and installed, i.e., a hydrasieve for
hair removal. Several cases of discharges of excess or problem waste
materials occurred. Examples include acid washing material, excess grease,
blood, hair, toe nails, and tripe. Many of the cases were traced to problems
with in-plant catch basins, valves, drains and various in-plant flow systems.
Typical treatment plant difficulties resulted, such as clogging of
piping, pumping problems and damage to mechanical equipment. The hand-cleaned
bar screen installation required additional operator time as a result of some
of the discharges.
The importance of cooperation and correlation of operations was
continually stressed and improvements have been noted. This is not a unique
experience but again demonstrates the need for a close working relationship
with product operations and wastewater treatment.
PRIMARY UNITS - AERATION, FLOTATION, SETTLING
The tubular conveyor units did not exert enough force or create an
adequate velocity pattern to withdraw solids from a very large area near its
bottom location. The settled solids that were not moved by the conveyor
remained and tended to bridge near the conveyors. The organic solids became
anaerobic and contributed to the poor performance of the primary units (see
Figure D-6).
The chain drive mechanisms of the conveyors froze during winter
operation. The drives were covered with metal shields and heating units were
installed to prevent freezing (see Figure D-4).
The grease skimming flight operation was initially withdrawing large
amounts of water with the grease. Staggered slots were cut in the flights to
allow water to escape as the flight rose to the screw auger channel and this
improved the quality of grease recovered.
14
-------
One thousand-gallon cylindrical grease hauling tanks, with overflow
shutoffs and steam heaters, were fabricated for continuous grease removal,
The grease is returned to the processing plant for recovery.
AERATION CHANNELS
Cage type rotors (Lakeside) were initially installed in the east channel.
It is understood that this was the first installation of a 15-foot length
unit. Various difficulties developed during the first year of operation
(November 1969 to November 1970), These included leaking seals, loose bolts,
and bearing difficulties.
Cracking of the blades was also observed. The blades were tested and it
was reported that they were cracking due to metal fatigue. Some of the lost
blades damaged electrical conduits. Various new blade shapes and welding
techniques were tried without success. The 12 cage rotors were replaced (by
Lakeside) with 12 mini-magna rotors of a new design (November to December
1970). These units have continued in operation satisfactorily (see Figures D-
8, D-ll, and D-12).
The initial operation of the magna rotors also presented several
problems. The problem of moisture entering the motors was corrected by
installing motor covers to protect the units. Some rotors broke at the stub
shaft weld. New welds were made and they have been satisfactory to date.
Considerable icing problems occurred during the two winters of operation.
The catwalks were constructed adjacent to the rotors and the top of the rotor
is near the catwalk surface. This resulted in considerable splashing onto the
catwalks. Ice built up on and adjacent to the catwalks and rotors, Ice
chunks that would break loose would damage the rotor blades and working
conditions were hazardous in the areas near the rotors (see Figures D-13 and
D-15).
Splash shields were designed and installed to control the icing problem.
One shield design was curved to essentially cover the typical upward spray
pattern of the rotor. These units have worked quite well. A flat vertical
splash shield was also used. It is less effective but provided some relief
(see Figures D-14 and D-16).
Another icing complication occurred during weekend operation with low
flows. The long liquid retention time, extensive spraying and large air-water
interface permited the lowering of the liquid temperature to freezing
conditions. Condenser waters were directed to the treatment plant to help
prevent or minimize icing conditions.
The floating aerators were added as a safety factor to provide additional
aeration capacity. Some experimentation with wall mountings and cables was
necessary to obtain a reasonably secure installation. The cone on each of the
50-horsepower units collapsed after about six months of operation. The units
are normally utilized with greater depths and distances from walls and other
15
-------
units. The cones were redesigned and replaced and they have continued in
operation satisfactorily (see Figures D-9 and D-10).
STRAIGHTLINE SETTLING UNIT
This 475-foot long unit was located in the northern half of the western
16-foot wide interior channel. The unit is 6 feet deep and has a 44-foot long
flight collector and a sludge hopper on the influent end. The design provided
that the mixed liquor would enter through wall ports at the north end. During
the settling phase, the flow was to the south end where the effluent
discharged via an overflow weir trough. At the completion of the settling
phase, a discharge valve would be closed. A cage rotor was turned on to re-
suspend the solids that settled to the floor beyond the collector. The
velocity pattern created in the channel would in essence permit the
sedimentation unit to function as part of the west aeration channel via its
interconnection at the wall ports in the north end of the unit,
The detention time and overflow rates are shown in Table 2.
TABLE 2. DETENTION TIME AND OVERFLOW RATE
Flow,
mgd
1.0
1.5
2.0
Time,
hrs.
8.3
5.5
4.1
Overflow rate,
gpd/sq.ft.
130
196
260
It was originally intended that there would be a second settling unit in
the southern half of the channel and the two units would operate alternately.
Only the north unit has been utilized.
The cage rotor system did not re-suspend the solids adequately. To
develop a flushing action, a door into the west aeration channel was installed
at the sourh or clarified effluent end of the settler. This door was opened
periodically (manually or on a time clock basis) and it was expected that the
flow reversal along with the cage rotor would re-suspend the solids and return
them to the aeration channel via the wall ports. This system did not function
satisfactorily. Considerable turbulence developed in the region of the
16
-------
effluent weir trough and solids were carried over the weir. This was due in
part to the difficulty of sealing the flusing door. As in the above system,
some of the settled solids were removed via the collector and hopper as
desired. It was also difficult to obtain a concentrated sludge via the
collector due to the turbulence near the wall ports in the sludge hopper area
(see Figures D-17 through D-22).
Various modifications. to the flushing operation were considered. The
inlet to the straightline was relocated near the center of its length. This
resulted in some performance improvement in effluent quality and solids
concentration of the settled sludge solids.
The cycling operation of settling and re-suspension is also not
desirable. A design modification employing a positive vacuum sludge
withdrawal throughout the length of the unit was developed and proposed as a
solution. The unit would be mounted on the side walls of the settler. It
will also provide a controlled basis for sludge wasting and recycle which is
not presently available for the west channel.
In summary, although the concept of utilizing an available interior
channel has merit, the performance of the unit was not successful because of
the design of the inlet, outlet and sludge collection system in the channel.
17
-------
SECTION 6
PROCESS EVALUATION
PROJECT OBJECTIVES
The primary objective of this project was to determine the effectiveness
of the channel aeration activated sludge process in achieving BOD and nitrogen
removal from packinghouse wastewater. In meeting this objective, several
component studies were included.
1. Evaluation of the performance of the in-plant and primary
treatment units as they affect the performance of the
activated sludge system.
2. Study of the effect of variations in process parameters such
as retention time, mixed liquor solids levels and organic
loadings on organic removal and waste sludge quantities.
3. Study of the nitrogen balance and process factors affecting
it.
4. Evaluation of the performance of a new channel sedimentation
unit design.
5. Evaluation of solids disposal systems including the
potential of waste activated sludge as an animal feed
supplement.
SAMPLING AND ANALYTICAL PROGRAM
Grab and composite sampling techniques were used in the study. Composite
samples were collected from the plant influent, from the primary effluent and
from each of the final clarifier effluents. Individual grab samples were
taken at these locations and process points as needed.
The composite sample of plant influent was collected with a chain and
scoop sampler. The sampler can be seen in Figure D-5 The primary effluent
and final effluent samples were collected with a Lakeside Corporation Trebler
Sampler. The composite samples were proportional to flow and the samples were
refrigerated.
18
-------
Normally, daily samples were collected at the composite locations. The
number of tests conducted on the samples varied with the type of evaluation
being conducted. The limited number of reported values in some of the tables
resulted from neglecting data from periods of plant by-passing, composite
sampler failures and other related equipment problems of which there were
several instances as described in this report.
The following analyses were routinely conducted: chemical oxygen demand
(COD), BOD5, total suspended solids, volatile suspended solids, grease,
ammonia nitrogen, chlorides, temperature. Total and filtrate COD and BODs
determinations were made to eliminate the effect of the final clarifiers in
the process evaluation. The test procedures were conducted in accordance with
US Environmental Protection Agency guidelines and the 12th Edition of Standard
Methods for the Examination of Water and Wastewater, 1955[UnitedStates
Public Health Service).Additional tests were conducted on sludges and for
control of the aeration channels (dissolved oxygen, MLSS, filamentous
bacteria).
WASTEWATER CHARACTERISTICS
Table 3 presents the characteristics of the wastewater flow received at
the treatment plant. The values are typical of packinghouse wastewater as
noted in the Meat Industry Guide (United States Public Health Service.
Industrial Waste Guide - Meat Industry. USPHS Publication Number 306. 1965),
by Rohlich (Rohlich, G. A. Eutrophication and the Meat Industry. 65th Annual
Meeting, American Meat Institute, University of Wisconsin, October 1970), and
Steffen (Steffen, A. J. Waste Disposal in the Meat Industry - A Comprehensive
Review. Proceedings of the Meat Industry Research Conference, March 1969).
The flows received were approximately 15 percent lower than those predicted
for design while the BOD load (36,000 pounds per day based on median values)
closely approximated the predicted loading.
Figure 4 presents the LWK during the study period. The low period in
April 1971 was during a period of partial plant shutdown. Other unusually low
periods such as April and May 1972 relate to brief periods of kills limited to
beef or pork only.
A selected data plot of total flow versus date is presented in Figure 5.
Data from days on which any by-passing was practiced were eliminated to
provide a proper representation of the actual flows. Most of the low flows
represent weekend operation when production activities were very limited.
There was a partial plant shutdown, as noted above, which reduced flows; most
notably in the April 1971 period.
19
-------
TABLE 3. CHARACTERISTICS OF WASTEWATER FLOW
Characteristic
Live Weight Kill
CLWK), Ibs.
Flow rate, mgd
Chemical Oxygen
Demand (COD), mg/1
Biochemical Oxygen
Demand (BOD5), mg/1
Total suspended
solids, mg/1
Volatile suspended
solids, mg/1
Grease, mg/1
Ammonia nitrogen
as N, mg/1
Chlorides, mg/1
COD/BOD ratio
Temperature, °F
90%
2,381
3.31
2,970
2,670
1,530
1,060
910
17.2
2,000
2.94
-
Median
1,978
2.69
2,340
1,600
920
725
570
11.4
1,310
1.86
89
101
1,322
1.55
1,150
900
570
480
270
6.3
985
1.05
-
Pounds per
1,000 LWK
_
1,316*
31.5
16.5
11.0
9.6
5.9
0.2
20.9
-
-
Number
of Values
225
223
52
101
223
62
130
19
17
28
-
*1,316 gallons per 1,000 LWK.
20
-------
8
8,
8
§
s
08
CD
88
« t
HRT
jm.
SEP.
MOV.
JAN.
NRR.
1971
Figure 4. Live weight kill versus date.
1972
NRT
JU.T
-------
1C
Q
£8
1C
8
-» - 1
4 I I »-
JAN.
MAT
JULT
1971
SEP.
NOV.
JAN.
HRT
Figure 5. Total flow versus date
-------
SECTION 7
PRIMARY TREATMENT PERFORMANCE
REMOVAL OF ORGANICS AND SOLIDS
Table 4 lists the performance of the primary units, Table 5 shows
detention times and overflow rates for sedimentation unit, and Table 6
presents the primary effluent characteristics. The data presented and
analyzed excludes periods of by-passing and includes analytical results based
only on composite samples. The plant design was expected to obtain suspended
solids and grease removals from 30 to 40 percent. These removals were not
reached most of the time. The increase in ammonia nitrogen was due to a
breakdown of the organic nitrogen (protein) which likely occurred in the
sludge accumulation in the settling tank.
The aeration compartment has a nominal retention time of 15 minutes at
2.7 million gallons per day and 12 minutes at 3.3 million gallons per day.
Air flow is restricted such that the minimum flow of air is supplied to
provide flow velocities for facilitating grit removal. Operation with and
without aeration showed no significant increase in grease removal in the
gravity separation basin following the aeration compartment.
A limited study of grit removal quantities yielded values ranging from
390 to 800 pounds per day. This results in a median removal rate of 0.2
pounds of grit per 1,000 gallons of flow. Over 70 percent of the flow is
subjected to grit removal in the packinghouse prior to discharge to the
primary treatment unit. The tubular conveyors did not operate satisfactorily.
During intermittent operation of the conveyors, solids tended to bridge over
the inlet slot and hinder flow of sludge into the conveyor. Wear on the
conveyor plates and chain is such that life expectancy is reduced to less than
2 years.
Plots of percent removal versus flow for suspended solids, grease and BOD
are shown in Figures 6, 7, and 8. There is little or no correlation with flow
rate. The settling unit overflow rates were high and the nominal retention
time low. In addition, the peak flow to the treatment plant was normally
sustained for approximately 12 hours each day with a peak to average flow rate
ratio of 1.2 to 1 (see Figure 1).
In addition, the inadequate settled solids removal due to the performance
of the tubular conveyors contributed to the poor performance. Anaerobic
conditions developed in the unit which is evidenced by the release of ammonia
nitrogen from the sludge. This increase in ammonia nitrogen resulted in an
23
-------
TABLE 4. PERFORMANCE OF PRIMARY UNITS*
Parameter
COD
BOD
Total suspended solids
Volatile suspended
solids
Grease
Ammonia nitrogen as N
90%
32.2
29.9
43.8
35.7
49.8
-23.4
Median
12.2
9.5
18.6
11.1
22.8
-73.7
10%
- 4.5
- 7.4
- 9.6
- 26.9
- 5.6
-279.0
Number
of Values
47
82
194
58
115
18
*Percent removal.
TABLE 5. SETTLING UNIT DETENTION TINE AND OVERFLOW RATE
Detention Time, Overflow rate
Flow, mgd minutes gpd/ft2
2.0 70 1,000
2.7 52 1,350
3.5 40 1,750
24
-------
TABLE 6. PRIMARY EFFLUENT CHARACTERISTICS
901, Median, 10%, Number
Characteristic mg/1 mg/1 mg/1 of Values
COD 2,660 2,040 1,080 48
BOD5 2,315 1,400 725 87
Total suspended solids 1,190 724 450 195
Volatile suspended solids 915 636 436 59
Grease 660 420 220 119
Ammonia nitrogen as N 41.6 21.0 9.0 18
Chloride 1,930 1,330 1,060 17
COD/BOD ratio 2.81 1.86 1.24 26
25
-------
8
9
8
d
8
8
8
0 O
8
en
0°
IT
UJ
O.
00
m
0 o
C 3^
95
0 O
O 0
3 ,-,
8
§
P..
*
8
8
0.00 0.7S 1.50 2.K 3.00 3. 75
TOTOL ROW FLOW (MGDl
6.00
Figure 6. Percent removal suspended solids (primary) versus flow.
26
-------
-
i
-
o
8
O
8 000°
*
QC
3
g2
UJ
JsJ
8
V
:
B
3° ° " V ^ C (9 0
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-
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'0.00 0.75 1.50 ?.» 3.00 3.75 "4.50 5.« 6.00
TOTPL RRw FLOW (MOD)
Figure 7. Percent removal grease (primary) versus flow.
27
-------
8
i
f ::
IT)
> .
r7
8
8
o o
0
0
o°3 <*
-------
increased oxygen demand to the channel aeration system and it is also the
primary cause of the increase in ammonia nitrogen in the treatment plant
discharge.
The anaerobic activity also adversely affected the COD, BOD and suspended
solids removals. Solids were buoyed to the surface and organics released from
the settled solids. The resulting median primary effluent BOD loading to the
secondary units was 34,500 pounds per day, which is 33 percent higher than
design predictions of approximately 26,000 pounds per day.
SOLIDS AND GREASE DISPOSAL
Typical grit removal characteristics are are shown in Table 7 (December
TABLE 7. GRIT QUANTITIES AND CHARACTERISTICS
Total Solids,
%
18.5
38.4
22.6
33.8
20.8
26.8
27.4
Total Volatile
Solids, %
13.8
19.0
18.1
20.4
16.6
18.6
-
Weight, Ib/day
385
800
470
700
435
535
560
The grit is high in organics ranging from 50 to 80 percent volatile. Landfill
procedures were used for grit disposal.
Primary sludge removal was inadequate and the quantities were very low
ranging from 600 to 2,000 gallons per day. The tubular conveyors cannot
remove sufficient solids unless they are operated near continuously. However,
the plant sludge hauling equipment had a limited capacity with a maximum
29
-------
practical removal rate of approximately 6 gallons per minute (8,640 gallons
per day). Sludge removal was normally conducted from 2 to 6 hours daily.
Typical primary sludge characteristics are shown in Table 8.
TABLE 8. PRIMARY SLUDGE CHARACTERISTICS
Parameter Average, I Range, %
Total solids 12.4 8-15
Total volatile solids 10.2 7-11
Grease content of dry solids 28.0 9-47
Protein content of dry solids 22.1 21-24
The volatile content averaged 82 percent and the sludge contained 50 percent
grease plus protein. Recovery of the sludge solids under present operation is
not feasible. The anerobic condition of the sludge solids and the relatively
low protein content on a wet weight basis were the primary negative factors.
Considering the quantity of suspended solids discharged with the primary
effluent, primary treatment modifications could significantly increase the
sludge collected and increase the potential for its use in a by-product.
Grease skimmings from the primary unit averaged approximately 2,700
pounds daily. The skimmings are returned to the rendering department for
grease salvage. The grease content averaged 12.5 percent on a wet weight
basis.
PILOT PLANT STUDY - DISSOLVED AIR FLOTATION
In order to evaluate potential means for recovering grease and protein
plus improving the waste treatment plant performance, a dissolved air
flotation pilot plant study was conducted. A 30 gallon per minute unit was
operated for a 2-week period. Raw waste after bar screening was supplied as a
feed source. The waste had a COD of 3,570 milligrams per liter, a suspended
solids concentration of 1,390 milligrams per liter and a grease content of 970
milligrams per liter.
30
-------
The performance of the flotation unit is shown in Table 9. The values in
parentheses are the values for the existing primary treatment units (see Table
4).
TABLE 9. PERFORMANCE OF DAF UNIT*
Average
Range
Grease
77.6 (22.8)
63-93
COD
61.4 (12.2)
43-80
Suspended Solids
64.0 (18.6)
50-83
*Percent removal.
It can be seen that the dissolved air flotation performance is
substantially better than the existing plant units. Using a flow rate of 2.80
million gallons per day and median values for primary effluent from Table 6,
the dissolved air flotation unit would reduce aeration tank loadings for COD
33 to 56 percent, for suspended solids 31 to 54 percent and for grease 48 to
70 percent. These improvements are based on the pilot unit, its effluent
quality during the study and a predicted effluent quality using median raw
wastewater characteristics from Table 3. A full scale unit would probably not
be as efficient. However, the changes would still be very significant.
The value of the recoverable solids was also evaluated. The solids were
analyzed as 52 percent grease and 17 percent protein. Based on 75 percent
grease removal with a flotation unit, the value of the recovered solids was
estimated at from $128,000 to $186,000 per year based on a solids value of
from 4.5 to 6.5 cents per pound recovered.
One equipment manufacturer indicated that the existing primary treatment
units could be modified to function as a dissolved air process. The estimated
cost for the equipment and installation was approximately $60,000. This
modification would probably yield approximately 60 percent grease removal. An
approximate estimate of $250,000 was received for a complete separately
installed dissolved air flotation system. This'system would achieve at least
75 percent grease removal.
31
-------
SECTION 8
SECONDARY TREATMENT PERFORMANCE
The total secondary treatment system consisted of two parallel flow
systems receiving an identical influent as shown in Figure 2. They are the
east aeration channel followed by a circular clarifier and the west aeration
channel followed by a straightline settling unit. Each system operated
independently and their respective performance will be considered separately.
EAST CHANNEL (I) - CIRCULAR SETTLER
The operational characteristics of the east channel are presented in
Table 10. The flow to the channel is presented in Figure 9. The flow to the
channel was reduced to meet channel optimum operation and aeration capacity.
The east channel received approximately 35 percent of the plant loading. The
dissolved oxygen concentration is plotted in Figure 10. Most of the high
values are weekend or Monday values. The channel dissolved oxygen rose with
the light loading on weekends and normally was higher on Monday as a result.
The variation in channel temperature with time is ploted in Figure 11.
The temperature followed ambient air temperature changes as would be expected.
Several values near 40 degrees Farenheit (F) were recorded even with a median
influent temperature of 89 degrees F.
The MLSS level was also limited by aeration capacity. The MLSS levels
are plotted in Figure 12. Oxygen deficiencies and odor problems were observed
at the higher levels of MLSS.
The resulting organic loadings were similar to a lightly loaded conven-
tional process although the hydraulic retention time was quite long with a
median value of 3.6 days. Waste sludge data was limited; however, an approxi-
mate solids retention time (SRT) was from 5 to 6 days. This was based on a
waste sludge rate of 4,000 to 6,000 pounds per day plus the loss of solids in
the final effluent. The SRT was lower than anticipated due to the low MLSS
levels and limited aeration capacity.
The final effluent characteristics are presented in Table 11 and the
removal performance in Table 12. The removal percentages are based on primary
effluent values.
The total effluent BODS meets the State requirement for this plant 50
percent of the time. The poor performance periods of the east side were
32
-------
TABLE 10. OPERATIONAL CHARACTERISTICS - EAST AERATION CHANNEL (I)
Characteristics
Flow, mgd
Detention time, days
Mixed liquor, suspended
solids, mg/1
Mixed liquor, volatile
suspended solids,
mg/1
Sludge Volume Index
Dissolved oxygen, mg/1
Temperature, °F
Applied BOD5, Ib/day
Volumetric loading,
lbs/1,000 cu. ft.
Loading factor,
Ibs/lb MLSS
90%
1.47
6.4
2,010
1,650
735
4.2
80
20,000
41.9
0.40
Median
0.98
3.6
1,425
1,250
382
0.8
63
11,900
24.7
0.26
10%
0.54
2.4
950*
1,025*
85
0.1
45
6,500
13.7
0.15
Number
of Values
214
214
361
86
359
353
340
77
77
77
*The larger 10 percent value for mixed liquor volatile suspended
solids is an abnormality due to the data available and statistical
analysis conducted.
33
-------
:
- -
s
0
58
£
C
1^ j J">
_
-t (-
HOP.
JU.T
1971
SEP. NOV. JPN.
Figure 9. East channel flow versus date.
Mftfi.
1972
-------
-
JIM
HRT
1972
Figure 10. East channel dessolved oxygen versus date.
-------
-
r
JKH.
1972
Figure 11. East channel temperature versus date.
-------
.
8
S{
8
08
8
81
8
s
JW.
NRT
JU.T
1971
1972
Figure 12. East channel MLSS versus date.
-------
TABLE 11. FINAL EFFLUENT CHARACTERISTICS - EAST AERATION CHANNEL (I)
Item
Total COD
Filtrate COD
Total BOD
Filtrate BOD
Total suspended solids
Volatile suspended solids
Grease
Ammonia nitrogen as N
Pounds of Effluent Parameter
Total COD
Filtrate COD
Total BOD
Filtrate BOD
Total suspended solids
Grease
Ammonia Nitrogen as N
901,
mg/1
695
260
455
92
840
372
77
32.0
per 1,000
8.8
3.2
5.6
1.0
11.3
1.0
0.45
Median
mg/1
260
102
70
22
142
42
21
18.3
Pounds Live
3.7
1.3
0.9
0.21
1.6
0.22
0.25
10%,
mg/1
86
58
21
6
31
16
5
6.4
Weight*
1.0
0.78
0.26
0.09
0.33
0.06
0.09
Number
of Values
61
29
125
26
233
55
37
29
59
29
125
26
230
35
29
*Based on flow distribution to the respective channels.
38
-------
TABLE 12. PERFORMANCE OF SECONDARY UNITS - EAST CHANNEL (I)
Number
Item 90% Median 10% of Values
Total COD removal
Filtrate COD removal
(total -filtrate)
Total BOD removal
Filtrate BOD removal
(total -filtrate)
Total suspended solids
removal
Grease removal
Ammonia nitrogen
removal
95.9
97.3
97.9
99.2
-
98.5
83.2
87.3
95.5
94.8
98.1
80.4
93.9
1.1
45.8
84.1
65.6
87.5
-
78.7
-71.7
52
26
80
22
-
30
15
39
-------
largely related to the poor settling characteristics of the sludge and
limiting aeration capacity for the system. The variation in the sludge volume
index during the study period is presented in Figure 13. Figure 14 presents a
plot of the sludge volume index versus the effluent total suspended solids
from the clarifier. High sludge volume indices generally correlated with high
effluent suspended solids and BOD values. During some periods of high sludge
volume index values, the sludge was examined microscopically and significant
numbers of filamentous bacteria were present. The mixed liquor also contained
from 11 to 14 percent grease and pieces of hair were observed.
The effluent suspended solids are plotted against flow in Figure 15. The
effluent suspended solids variations did not correlate with flow rate. The
detention time and overflow rate of the circular clarifier are shown in Table
13.
TABLE 13. CIRCULAR CLARIFIER DETENTION TIME AND OVERFLOW RATE
Flow, mgd
0.5
1.0
1.5
2.0
Detention
Time, hrs.
8.6
4.3
2.8
2.1
Overflow Rate,
gpd/ sq.ft.
190
380
570
760
The overflow rates are within acceptable design limits (see Figure D-23).
The BOD removal was analyzed with respect to the volumetric loading and
loading factor values and no correlation was evident. The volumetric loading
and loading factor are plotted against percent removal of BOD in Figures 16
and 17, respectively.
Changes in the ammonia concentration varied considerably. The median
final effluent value of 18.3 milligrams per liter is high and would be of
concern in plant discharges to small streams. Factors affecting the nitrogen
balance include the high proteinaceous organic loading, the limited aeration
capacity and the relatively low solids retention time. Temperature may also
be a factor during winter operation.
40
-------
8
S.
8
St
a
E
B
> i
JRM.
MRBI.
JU.T
1971
KSR. wrr
1S72
JULT
Figure 13. Sludge volume index versus date (east).
-------
8
>
in
8
rj.
8
o o
5
0
O O
oo o
CP
O O
o o
0
3
3
o o
foo
8 °° o
_o o o
Oee
o _ o
3 O
800 2
P
0 O
00
'
o oc
o o
?0.00 40.00 60.00 80.00 100.00 120.00
SUSP SOL TOTPLIMG/L) (XlQl I
140.00 160.00
Figure 14. Sludge volume index versus effluent suspended solids (east).
42
-------
8
8
0 O
V
ff
0
o
J 0 o
O o
O O o o
O 00
0°
00
-» h
-» »-
20.00 40.00 60.X 80.00 100.00 120.00 140.00 160 00
SUSP SOL TOTflL (MG/L) 1X10' )
Figure 15. Flow rate versus effluent suspended solids (east).
43
-------
8
ai
o
*
o
o o°
"8
« . °
0 ° 000
o o «
-------
s
d
o
~
en
I
' .
in
oo
8
3 3
t> -
-
3 9
O' ^
e
Li
O
15.00 30.00 45.00 60.00 7S.OO 90.00 10S.OO l?0.00
X REMOVRL BOD TOTRL
Figure 17. Loading factor versus percent removal BOD (east).
45
-------
The east rotor aeration system was a new design and no performance data
was available. The application of the floating aerators also was not under
normal design conditions. In addition, the 50-horsepower unit was redesigned
during the early phase of the project.
An approximation of the oxygen transfer capacity of the east aeration
channel (12 mini-magna's and 3 floating aerators) can be obtained by
considering the pounds of BQD5 satisfied in the aeration system. Using the
median channel loading of 11,900 pounds per day and a 98.1 percent removal
(Total-Filtrate in Table 12), the channel aeration system met an oxygen demand
(BOD5) of 11,670 pounds per day. During most of the period, 10 rotors were in
operation.
Based on median values, the overall treatment plant removals (untreated
versus total east effluent) would be 95.7 percent BOD5, 84.6 percent suspended
solids and 96.3 percent for grease.
WEST CHANNEL (II) - STRAIGHT-LINE SETTLER
The operational characteristics of the west channel are presented in
Table 14. The channel flow rate is plotted versus date in Figure 18. The low
values are normally weekend flows. Days of by-passing have been excluded.
The west channel received 65 percent of the plant loading or 1.85 times the
loading of the east channel. This loading distribution was a result of the
greater aeration capacity in the west channel. The dissolved oxygen and MLSS
levels are presented in Figures 19 and 20, respectively. The dissolved oxygen
levels are relatively low (median 0.8 milligrams per liter) as are the MLSS
levels. This resulted from the higher than predicted organic loadings and
limited aeration capacity.
The median organic loading (0.56 pounds BOD5 per pound MLSS) was higher
than the conventional activated sludge process and the median hydraulic
retention time of 1.9 days exceeded that for many extended aeration systems.
Due to the nature of the final settling tank operation, reliable waste sludge
information was not available. However, there was a significant loss of
solids in the final effluent. Based on median values, approximately 10,000
pounds of solids were discharged daily. Therefore, the solids retention time
in the west channel was in the range of 3 to 4 days. During several
operational periods, solids were also intentionally wasted from the unit.
The final effluent characteristics are presented in Table 15 and the
removal performance in Table 16. The removal percentages are based on primary
effluent values.
The effluent quality from the west system was consistently poor. This
poor performance is related to the operation of the straightline settling unit
and to periods of poor sludge settling properties. The sludge volume index
values are plotted against date and effluent suspended solids in Figures 21
and 22. Filamentous bacteria were identified in some sludge samples.
46
-------
TABLE 14. OPERATIONAL CHARACTERISTICS - WEST AERATION CHANNEL (II)
Number
Item 901 Median 10% of values
Flow, mgd 2.23 1.83 0.96 183
Detention time, days 3.6 1.9 1.6 183
Mixed liquor suspended
solids, mg/1 1,960 1,320 925 342
Mixed liquor volatile
suspended solids, mg/1 1,540 1,050 690 85
Sludge volume index 670 320 132 343
Dissolved oxygen, mg/1 5.6 0.8 0.2 332
Applied BODs, Ib/day 41,200 22,600 13,200 72
Volumetric loading,
lbs/1,000 cu.ft. 86.5 47.4 27.6 72
Loading factor,
Ibs/lb MLSS 0.91 0.56 0.28 72
47
-------
a
V
Q
£8.
(\j
O
cr
a
s
3 '
-t »
jflN.
MRP.
HPT
JULT
1971
S£P.
NOV.
JPN.
WW.
MRT
1972
Figure 18. West channel flow versus date.
-------
8
972
Figure 19. West channel dissolved oxygen versus date.
-------
1972
Figure 20. West channel MLSS versus date.
-------
TABLE 15. FINAL EFFLUENT CHARACTERISTICS - WEST AERATION CHANNEL (II)
Component
Total COD
Filtrate COD
Total BOD
Filtrate BOD
Total suspended solids
Volatile suspended solids
Grease
Ammonia nitrogen as N
Pounds of Effluent - Parameter per
Total COD
Filtrate COD
Total BOD
Filtrate BOD
Total suspended solids
Grease
Ammonia nitrogen as N
90%,
rag/1
1,535
200
780
48
1,250
820
295
38.5
Median,
mg/1
880
95
530
19
670
270
120
24.6
1,000 Pounds Live
21.7
3.2
9.5
0.7
13.7
3.6
0.56
9.2
1.2
5.3
0.25
6.8
1.7
0.30
10%,
mg/1
210
54
92
5
115
66
19
6.4
Weight*
3.3
0.60
1.1
0.07
1.6
0.29
0.10
Number
of values
31
16
83
16
188
54
26
26
29
16
83
16
185
25
26
*Based on flow distribution to the respective channels.
51
-------
TABLE 16. PERFORMANCE OF SECONDARY UNITS - WEST CHANNEL (II]*
Item
Total COD removal
Filtrate COD removal
(total -filtrate)
Total BOD removal
Filtrate BOD removal
(total -filtrate)
Total suspended solids
removal
Grease removal
Ammonia nitrogen removal
90%
88.2
97.4
92.2
99.3
-
92.9
70.0
Median
53.2
95.4
67.1
98.1
7.5
66.0
-50.5
101
-13.3
87.9
38.7
94.2
-
- 7.2
-164
Number
of values
30
16
65
16
_
24
14
*Percent removal.
52
-------
O-l
JAN
MBT
1971
Figure 21. Sludge volume index versus date (west).
1972
-------
5?
8
8
a,
' a
o
o
o °
f
.»e»^° .>'.
140.00 80.00 IM.OO 160.00 200.00 **0.00 ^80.00 i?0.00
SUSP SOL TOTRLIMG/U (X101 )
Figure 22. Sludge volume index versus effluent suspended solids (west).
-------
The hydraulic characteristics of the straightline unit are shown in Table
17.
TABLE 17. DETENTION TIME AND OVERFLOW RATE FOR STRAIGHTLINE SETTLER
Detention Overflow Rate,
Flow, mgd Time, hrs. gpd/sq.ft.
1.0 8.3 130
1.8 4.6 240
2.2 3.7 290
2,6 3.2 340
The overflow rates are quite low. An analysis of effluent suspended solids
versus flow rate (Figure 23) did not show any correlation.
As was noted earlier, the flow through this unit caused turbulent
conditions in the sludge hopper area and resulted in re-suspension of settled
solids. The cage rotor also was not adequate to re-suspend the solids that
had settled to the floor beyond the collector. A side door was installed near
the effluent weir trough to permit periodic hydraulic scouring of the settled
solids. This intermittent operation plus poor door seals created poor
settling conditions in the unit and solids were carried over the weir with the
final effluent.
The new inlet has been located near mid-length of the unit. This has
improved the performance but it still is inadequate. A revised tank design
has been proposed . incorporating a new sludge removal system and eliminating
the door to the aeration channel.
Although the organic loadings varied considerably, there was no signi-
ficant correlation between total BODs removal and organic loadings. The
relationship of volumetric loading and loading factor to the percent removal
of BOD is presented in Figures 24 and 25. The operational characteristics of
the system and the high organic loadings of proteinaceous wastewater resulted
in an increase in ammonia nitrogen and high effluent levels. As noted
earlier, these levels are of concern and are affected by various factors.
55
-------
S *rr~^J
0
' i
i <
T
" a
*
« O »
'
. *
.1
S
>
* \ * 1 1
-------
B
8
Oq
oS
8
in
QQ
i
8
8
o
o
o ° o
o
o
3t
o
o o
o o
o
o o /» o
0 o o o°
o
0 o
0
o
o
H , ». 1 h
15.00 90.00 US.OO 60.00 7S.OO 90.00 105.00 120.00
X REMOVRL BOO TOTPL
Figure 24. Volumetric loading versus removal BOD (west).
57
-------
3
in
o
00
to
03
o
o o o
S O 3
0
o
30
3
.1 o
3
°°
<9
£1
d
1 H 1 ( 1 1
15.00 30.00 15.00 60.00 75.00 90.00 105.00 120.00
X REMOVflL BOD TOTRL
Figure 25. Loading factor versus percent removal BOD (west).
58
-------
The floating aerator system was utilized in a non-standard application.
The magna rotors were rated at 4,8 pounds per foot per hour (tapwater, 0.0
dissolved oxygen, 20 degrees C) for 10.5-inch immersion and a rotor speed of
68 revolutions per minute. The west aeration channel also generally operated
at a steady-state oxygen level during weekday processing operations. Higher
weekend dissolved oxygen levels were reached in the west channel. Based on a
median channel BODs loading of 22,600 pounds per day and 98.1 percent removal
(Total-Filtrate in Table 16) the west channel aeration system satisfied an
oxygen demand of 22,150 pounds per day.
The overall removal efficiencies (unfiltered samples) for the west
aeration system are much lower than the east channel due to the performance of
the straightline settler. However, settling column studies indicated the
effluent quality of the west channel would likely be similar to that of the
east channel with the same type of settling system.
AERATION SYSTEM ANALYSIS
It would be desirable to analyze the oxygen transfer efficiency of the
aeration system. The lack of equipment ratings and several aspects of the
actual operation make any analysis uncertain.
The oxygen transfer of the magna rotors (west channel) was rated at 4.8
pounds per hour per foot of rotor at 10.5-inch immersion and 68 revolutions
per minute. No ratings were available for the newly designed mini-magna
rotors used in the east channel. The 20-horsepower floating aerators were
rated at 1,400 pounds of oxygen per day and the 50-horsepower units at 3,000
pounds per day. (Note; The above ratings are at zero dissolved oxygen in
tapwater at 20 degrees C).
The application of the floating aerators to this tank geometry (6-foot
water depth, 40-foot channel width) did not correspond to the manufacturer's
recommended installation. In addition, the drum on the 50-horsepower unit
collapsed and was replaced with a shorter drum length.
The rotor aerators caused high flow velocities in the channels. Surface
velocities exceeding 2.5 feet per second were observed. The manufacturer re-
reported that only a part of the design rating can be achieved if velocities
are significantly higher than 1.0 foot per second. In addition, when
analyzing the oxygen demand satisfied, there were periods when some aerators
were not operating.
The facilities were not designed nor evaluated to accurately determine
transfer efficiencies. The following are the best estimates possible. If one
assumed a transfer rate of 3,400 pounds per day for the floating aeration
portion and utilized the satisfied oxygen demands as noted above of 11,670
pounds per day (east) and 22,150 pounds per day (west) the magna rotors
transfer rate would be 4.3 pounds per hour per foot (180 feet operating) and
the mini-magna rate would be 2.3 pounds per hour per foot (150 feet
operating). The power consumption of the rotor aerators was not monitored
separately, therefore horsepower values are not available. Using
59
-------
manufacturer's data for the magna rotor (1.38 horsepower per foot), the magna
rotor rating would be 3.1 pounds per horsepower-hour per foot of rotor.
60
-------
SECTION 9
FINANCIAL CONSIDERATIONS
CONSTRUCTION COSTS
The total capital costs for construction (1970) of the wastewater treat-
ment facilities was $983,321.00. A detailed cost breakdown is presented in
Table 18.
OPERATION AND MAINTENANCE COSTS
Operation and maintenance costs for the facility during the demonstration
period during 1971 were $82,224.00. Similar monthly expenses were experienced
during 1972. A detailed breakdown is provided in Table 19. About 10 percent
of the total operation and maintenance costs are the result of additional data
collection and analysis required by the demonstration project.
An analysis based on the power requirements for the total plant operation
yielded the values shown in Table 20. (This includes aeration, pumping,
lighting and the operation of other plant equipment.)
Solids disposal costs were low during the study period because the grit
and sedimentation unit sludges were disposed of to a company-owned landfill
and waste activated sludge was discharged to the river. Projected annual
costs for solids disposal including capital costs are $46,600. Land disposal
will be used preceeded by air flotation, centrifugation and drying.
TOTAL ANNUAL COSTS
Total annual treatment costs can be viewed as the sum of (1) annual
capital amortization costs (6 percent for 20 years) and (2) annual operation
and maintenance costs. Some analysts include an annual equipment repair and
maintenance cost estimated at 3 percent of equipment capital cost. Table 21
shows the treatment costs during the 1971-1972* demonstration period. The
breakdown includes demonstration costs, since they constituted only a small
percentage of the total costs. The waste load during the study period was
835,000 pounds of BOD and 82 million gallons per month, respectively,
The R. T. French Company (R. T. French Company. Aerobic Secondary Treat-
ment of Potato Processing Wastes. Water Quality Office, US Environmental
Protection Agency. Report No. 12060 EHV WPRD 15-01-68. 1970) reported annual
61
-------
TABLE 18. CONSTRUCTION AND EQUIPMENT COSTS
Item
Cost
Earthwork $ 45,500
Caissons 6,500
Structural concrete 104,500
Channel concrete 188,000
Reinforcing materials 15,500
Masonry and precast slabs 4,800
Buildings, miscellaneous (roof, doors, paint) 11,000
Miscellaneous metals (rails, walkway, motor covers, etc.) 62,000
Interior piping and valves 38,000
Exterior piping 31,000
Plumbing, heating, ventilation 12,000
Fencing 3,000
Electrical 69,500
Rotor shields 22,500
Plant equipment
Grit aeration 7,400
Primary sludge collector 20,500
Grit and sludge conveyors 14,250
Raw sewage pumps 11,500
Sludge pumps 4,800
Instrumentation and flumes 5,800
Samplers 4,430
Fixed rotor aerators 110,690
Floating aerators 31,815
Circular clarifier 13,300
Laboratory equipment 7,500
Technical services
Preliminary studies and report 19,889
Plans and specifications 19,647
Supervision of construction 22,000
Post construction studies 46,000
Legal and fiscal 10,000
Administration 20,000
Total $983,321
62
-------
TABLE 19. OPERATION AND MAINTENANCE COSTS - 1971
Item Cost
Salaried (2 operators, 1 chemist) $45,127
Overtime, travel 3,272
Power 29,048
Consultant fees 2,971
Laboratory supplies 1,806
Total $82,224
TABLE 20. POWER REQUIREMENTS
Parameter 90% Median 101
Kilowatt hours per pound BOD
applied to aeration system 0.52 0.21 0.03
Killowatt hours per million
gallons per day - total flow 4,591 1,936 475
63
-------
treatment costs for an activated sludge plant at 0.038 cents per pound BOD
applied. Michael (Michael, R. L. Cost and manpower for municipal wastewater
treatment plant operation and maintenance, 1965-1968. Journal Water Pollution
Control Federation. 42:1883. 1970) reported annual operation and maintenance
costs for activated sludge plants (secondary treatment only) ranging from
0.0175 cents to 0.087 cents per pound of BOD applied. The annual treatment
costs at John Morrell and Company during the study period, 0.0168 cents per
pound BOD applied, are quite low in comparison. Reported costs for other food
processing waste treatment operations range from 0.04 cents to 0.06 cents per
pound of BOD applied.
The lower costs at John Morrell and Company are probably due to the lower
total labor costs, the method of solids disposal and the cost advantage
associated with treatment of large waste loads. Adding the extra capital cost
and operation and maintenance costs for solids handling and disposal would
result in total wastewater treatment costs of about 0.02 cents per pound of
BOD applied (0.33 cents per 1,000 pounds LWK).
TABLE 21.
TREATMENT COSTS
Item
Amortized capital cost
Operation and maintenance
cost
Total
1971
$ 85,725
82,224
$167,949
First half 1972
$42,862
37,875
$80,737
Estimated cost of treatment:
10,000,000 Ibs BOD/year
19,400,000 Ibs COD/year
984,000,000 gallons/year
$0.0168 per Ib BOD applied
0.009 per Ib COD applied
0.171 per 1,000 gallons of flow
64
-------
SECTION 10
WASTE ACTIVATED SLUDGE UTILIZATION
CHARACTERISTICS AND TREATMENT
The quantity and quality of the sludge varied throughout the study as
noted in the channel discussions. The waste sludge evaluated varied in
initial solids content from 0.3 to 0.6 percent. Pilot studies of thickening
included air flotation and centrifugation.
A pilot model air flotation unit (EIMCO) with a design flow rate of 30
gallons per minute was used. With a 50 to 60 percent effluent recycle, the
waste sludge volume flow rate is reduced to 15 gallons per minute. In a study
with a feed sludge concentration of 0.3 percent, the float was 2.5 to 3
percent and the underflow 0.03 to 0.05 percent solids.
Two separate centrifugation studies were performed, one with a scroll-
type bowl and the other a basket-type bowl. The sludge cake yield was too low
and of poor quality with the scroll-type unit. Sludge samples of feed to and
from the pump showed a straining effect and required a greater flocculation
time. These factors affected the centrifuge performance.
A 12 by 6 inch solid bowl centrifuge performed very well on settled waste
sludge; high recoveries and very high cake concentrations were achieved
without the use of chemicals. The sludge was fed to the unit using a
centrifugal pump. The results of six runs made at different flow rates at
1,300 G (gravity forces) are shown in Table 22.
The data indicates that a basket centrifuge can effectively concentrate
waste activated sludge from the oxidation ditch process. At moderate feed
rates concentration of the cake is not affected by feed concentration. The
data will not be used to size units for the operation since pre-thickening by
air flotation or other means is essential from an economic viewpoint.
ANIMAL FEED SUPPLEMENT
The project objectives included an evaluation of the use of waste
activated sludge as an animal feed supplement due to its predicted high
protein content.
Several samples of waste activated sludge were collected and analyzed.
The sludge was dried, then analyzed for specific constituents. The nitrite
65
-------
TABLE 22. BASKET CENTRIFUGATION OF WASTE ACTIVATED SLUDGE
Feed
gpm
1
1.5
2
2
3
4
% solids
0.5440
0.5410
0.5230
0.2965
0.3990
0.3760
Cake soli
\
9.3
7.8
8.5
9.0
9.3
8.3
j_ Solids recovery C%) versus time
cu) ,
5 min.
89
87
84
87
66
49
10 min.
88
84
79
81
67
46
15 min.
87
73
48
80
55
37 .
20 min.
82
48
-
81
49
35
66
-------
and nitrate content was zero or less than 0.1 percent. The results are
presented in Table 23.
Protein evaluation tests were made on three different samples of dried
sludge. In these tests, 0.24 grains of nitrogen per day is fed to a set of
five rats over a five-day period. The weight gain in grams during the five-
day period is an accepted measure of the value of the protein as feed
supplement. A value of 2 to 8 is considered equivalent to a high grade
tankage. A value of 8 to 12 is equivalent to meat scraps fortified with
blood. The higher the value, the more complete is the amino acid complement.
The results are shown in Table 24.
The first two samples were collected coincident with normal packinghouse
operation. The last sample was collected when the hog operation was down.
All three values indicate a good source of protein, but suggest a deficiency
in at least one of the essential amino acids.
Based upon positive possibilities from the protein evaluation studies, a
rat feeding study was performed. Sludge collected during centrifugation tests
was oven dried and blended with sodium caseinate and other standard feed
ingredients. The rats used for the study were from an in-house rate colony.
The test animals were raised, selected and fed the mixture under standard
controlled conditions. Analysis of the sludge is shown in Table 25.
TABLE 23. COMPOSITION OF WASTE ACTIVATED SLUDGE
Percent present
Component
Protein
Moisture
Fat
Fiber
Ash
Calcium
Phosphorus
09/01/71
53.2
7.1
9.3
5.2
13.2
1.7
1.8
09/21/71
45.1
5.1
20.0
2,5
14.6
-
-
11/27/71
46.3
1.4
19.9
-
13.7
1.8
1.3
67
-------
TABLE 24. PROTEIN EVALUATION TESTS
Date
3/25/71
4/7/71
5/13/71
Protein value
5
8.4
3.5
Salt content, 1
14.8
6.4
0.8
TABLE 25. COMPOSITION OF SLUDGE
Constituents Percent
Moisture 5.1
Crude protein . 45.1
Crude fat 20.0
Crude fiber 2.5
Ash 14-6
Salt 1-7
Nitrogen free extract 12.7
Calories per pound 18.7
68
-------
The actual diet was prepared to provide a finished protein content of 10
percent and a fat content of 5 percent. This was to eliminate variations of
the caloric value with the only variable being the kind of protein in the
diets. Results from the feeding test are presented in Table 26.
The results indicate that use of 25 percent sludge in the total protein
of a feed would produce good feeding results. Survival and net gain by all of
the animals on the 100 percent sludge diet shows that all of the essential
amino acids are present. The level, however, is not sufficient for normal
expected growth. This is borne out by the level of gain at 50 to 75 percent
sludge protein. A sample of sludge was analyzed for amino acids. The results
are as shown in Table 27.
Based on this analysis, the sludge appears to have potential for
replacing soybean meal in certain types of swine rations and layer rations.
The methionine value is significant in that one pound of activated sludge
would replace 1.5 pounds of soybean meal on a methionine basis.
These results indicate that the sludge is a suitable feed supplement,
however, additional testing is necessary.
69
-------
TABLE 26. RAT FEEDING TEST
Diet protein
100% caseinate
25% sludge
75% caseinate
50% sludge
501 caseinate
75% sludge
25% caseinate
100% sludge
Average weight
gain, grams
168.5
159.9
136.3
81.4
30.4
Average food
consumed, grams
752
813
795
671
429
Gram food/gram
gain, 60 days
4.53
5.16
5.87
8.29
13.93
Efficiency
60 days, %
22.3
19.8
17.1
12.1
7.2
-------
TABLE 27. AMINO ACID ANALYSIS OF ACTIVATED SLUDGE*
Amino acid
Lysine
Histidine
Arginine
Aspartic acid
Threonine
Serine
Glutamic acid
Proline
Cystine
Glycine
Alanine
Valine
Methionine
Isoleucine
Leucine
Tyros ine
Phenylalanine
Percent
1.65
0.32
1.25
3.73
1.97
1.49
4.72
1.29
0.35
2.46
3.10
2.10
0.93
1.53
2.77
2.21
2.45
*Total crude protein (N x 6.25), 44.80%.
71
-------
SECTION 11
EFFLUENT CHLORINATION
A laboratory scale evaluation of the effluent chlorination requirements
for this treatment system, was conducted. The total and fecal coliform
organism counts varied widely. It should be noted that most of the sanitary
wastewater from plant operations is discharged to another sewer system. The
results of a typical analysis (February 7, 1972] are noted in Table 28.
TABLE 28. TYPICAL COLIFORM RESULTS
Total Coliforms, Fecal Coliforms,
Sample Location
48 -inch sewer
Treatment plant influent
Treatment plant effluent
number/100 ml
4,700,000
16,300,000
6,900,000
number/ 100 ml
2,800,000
1,180,000
280,000
A series of experiments (Jar test apparatus) were conducted in December
1971 utilizing final clarifier effluents. The effluent sample quality and
test results are presented in Table 29.
A free chlorine residual was obtained in almost all cases where the
applied chlorine dosage was 15 milligrams per liter or greater. Organism
reductions were very good, exceeding 99 percent, and in practically all cases
the final effluent fecal coliform count was less than or equal to 10 organisms
per 100 milliliters. Based on these tests, a chlorine dosage in excess of 10
milligrams per liter and a contact time of approximately 15 minutes would
achieve excellent fecal coliform reduction. For this plant design a contact
chamber would need to be added to achieve adequate contact time. The outfall
sewer would only provide 5 to 7 minutes of contact time.
72
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TABLE 29. FINAL EFFLUENT CHLORINATION
Run
No.
A.
I
II
III
IV
V
Run
No.
B.
I
II
III
rv
V
Total coliforms,
number/100 ml
Fecal coliforms
number/100 ml
NH3-N as N,
mg/1
Suspended
solids, mg/1
PH
Temperature ,
OG
Effluent Sample Quality
240,000
120,000
360,000
520,000
240,000
Contact time,
rain.
107,000
22,000
49,000
55,000
32,000
Applied, mg/1
19.2
10.2
10.2
12.5
11.8
Total residual,
mg/1
136
92
216
134
128
Free residual,
mg/1
7.6
7.4
7.4
7.3
7.3
Total coliforms,*
number/ 100 ml
13
10
11
12
12
Fecal coliforms,
number/100 ml
Test Results - Chlorinet
20
15
20
10
30
20
20
5.3
10.6 to 26.6
10.6 to 26.6
10.1 to 25.3
15.2 to 25.3
5.1 to 15.2
5.1 to 20.2
5.1 to 20.2
2.2
5.3 to 18.4
6.0 to 18.8
7.6 to 23.0
14.4 to 22.5
1.6 to 17.5
2.9 to 17.1
2.6 to 17.1
0.0
0.0 to 0.8
0.0 to 1.2
0.2 to 1.1
0.2 to 1.1
0.0 to 0.2
0.0 to 0.2
0.0 to 4.6
1,010
< 10
< 10
--
--
--
< 10
I10
50
< 10
< 10
<" 10
< 10
< 10
< 10
1 10
*The 5.1 mg/1 dosage tests in run numbers IV and V resulted in total coliform counts of 20/100 ml.
other tests were less than or equal to 10 organisms/100 ml.
tExcept for run number I (20), a series of tests at various applied chlorine dosages were conducted.
All
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SECTION 12
PERTINENT PUBLICATIONS
Ahrens, G. E. 1969. Morrell Pioneers More Efficient Aeration. Food
Engineering.
Paulson, W. L., D. R. Kueck, and W. E. Kramlich. Oxidation Ditch Treatment of
Meat Packing Wastes. Second National Symposium on Food Processing Wastes
Proceedings, March 1971.
Paulson, W. L., L. D. Lively, and J. L. Witherow. Analysis of Wastewater
Treatment Systems for a Meat Processing Plant. Twenty-seventh Annual
Purdue Industrial Wastes Conference Proceedings, May 1972.
74
-------
-
E
JAN.
MAT
1972
Figure A-l. Pounds suspended solids/live weight killed versus date (raw)
-------
tt
9.
I
i
o e
-*-
4-
SO
100 190 MO
PR1 EFF TSS (MC/L)
(XlQl )
woo
Figure A-2. Raw total suspended solids versus primary effluent total
suspended solids.
76
-------
g
£8
is
is-
UJ
E
;*
8
8
8..
8
I 4
i > « > *
I I
1 4
HMT
1972
JPH.
HRT
JULT
1971
SEP.
N9V.
Figure A-3. Percent removal suspended solids versus date (primary).
-------
3
8
o
8
8 o .
i
S
8
-5- -5-
e
9
o o o o
o
0 08°
o °° °
°,
o o o o
0
e e°o
g . .aoo
e o
e
e
o e
o
Q
O O
o o
O O ^tJ
o S» - o o
t
X - - ,
TJ.OO 12.50 25.00 97.50 50.00 62.50 75.00 87.50 100.00
Pfll EFF GRE«SE(MG/L) (X10> )
Figure A- 4. Raw grease versus primary effluent grease.
78
-------
s
-M
ifi
a
o
c
0
o
o
o
o
e
o
9e> e
o 9 o o
o
o i e
8
o
o o o o o
e i o o o
e o e i
o o o
o o
o
o
so too iso am 2so an aso uoo
PRI EFF BOO (MC/U (X10» )
Figure A-5. Raw BOD versus primary effluent BOD.
79
-------
1972
Figure B-l. East effluent suspended solids versus date.
-------
Jtt
Figure B-2. East effluent pounds suspended solids/live weight killed versus date.
-------
oo
JU.T
1971
Figure B-3. East effluent BOD total versus date.
-------
1972
NRT
Figure B-4. East effluent pounds BOD total/live weight killed versus daxe.
-------
oc
e
JfiK.
1S72
Figure C-l. West effluent suspended solids versus date.
-------
00
en
JR*
1972
Figure C-2. West effluent pounds suspended solids/live weight killed
versus date.
-------
90
r
*2i
03R
u.
ll.
LJ
8
K
JON.
WW. *n JULT SEP. NOV. JAN.
1971
Figure C-3. West effluent BOD total versus date.
1972
HOT
-------
oo
s
s
co
8
«"
8
JM.
* « 1 1-
NOT
JJL1
1971
SEP.
JfiN.
KSPI.
1372
Figure C-4. West effluent pounds BOD total/live weight killed versus date.
-------
APPENDIX D
DES MOINES RIVER BASIN
IOWA NATURAL RESOURCES COUNCIL
1953
(
. .'._ N
Figure D-l. Plant site location.
-------
Figure D-2. Aerial view of treatment system in construction.
89
-------
_
o
Figure D-3. Treatment plant.
-------
c
Figure D-4. Heating unit modification to tubular conveyor system.
-------
Figure D-5. Pre-aeration primary unit and composite sampler.
-------
Figure D-6. Tubular conveyors in primary system.
93
-------
p
Figure D-7. Grease wagons and solids disposal carts.
-------
Figure D-8. Rotor and floating aerators in west channel.
-------
?
Figure D-9. Fifty-horsepower floating aerator.
-------
Figure D-10. Drum failure of 50-horsepower floating aerator.
97
-------
Figure D-ll. Typical blades of rotor aerator.
98
-------
Figure D-12. Close-up of rotor aerator operation - east channel,
99
-------
:
:
Figure D-13. Icing problems with rotor aerators and walkway.
-------
Figure D-14. Initial flat shield design for icing conditions.
-------
o
Figure D-15. Icing problems and motor covers rotor aerators,
-------
Figured-16. Curved shield system to minimize icing.
-------
:
-
Figure D-17. Inlet and sludge collector area for straightline settler.
-------
Figure D-18. Side inlet port to straightline settler.
105
-------
3
Figure D-19. Straightline settler and cage rotor - drained.
-------
:
Figure D-20. Straightline settler in operation.
-------
-
Figure D-21. Effluent weir for straightline settler.
-------
Figure D-22. Turbulence and flushing door location - straightline settler.
-------
Figure D-23. Circular settling unit - east channel,
-------
TECHNICAL REPORT DATA
(Please read Inductions on the reverse before completing)
1. REPORT NO.
EPA-600/2-79-030
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
OXIDATION DITCH TREATMENT OF MEATPACKING WASTES
5. REPORT DATE
January 1979 issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
Wayne L. Paulson and Lawrence D. Lively
9. PERFORMING ORGANIZATION NAME AND ADDRESS
10. PROGRAM ELEMENT NO.
1BB610
John Morrell and Company
Chicago, Illinois 60604
11. CONTRACT/GRANT NO.
12060 EUB
12. SPONSORING AGENCY NAME AND ADDRESS
Industrial Environmental Research Lab. - Cinn, OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Technical 1966-1972
14. SPONSORING AGENCY CODE
EPA/600/12
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The analysis of 18 months of early operation for a channel aeration activated
sludge wastewater treatment plant is presented, The treatment plant receives an
average flow of 2.8 million gallons per day from the John Morrell and Company,
Ottumwa, Iowa hog and beef meatpacking plant. The treatment plant includes pre-
aeration, primary settling and grease removal followed by two 3.5 million gallon
aeration channels (40 by 6 feet deep by 1,050 feet in length) in parallel. Rotor and
floating aerators are utilized. One channel utilizes an experimental straightline
settling unit (16 by 475 by 6 feet deep).
The design and operation of the primary treatment units was inadequate. Tubular
conveyors for sludge removal were not satisfactory. More efficient grease and
suspended solids removal is needed prior to the aeration process. The channel
aeration activated sludge process is capable of achieving organic removals of 90 to
95 percent from meatpacking wastewater. High effluent ammonia levels are of concern.
Various plant design changes are needed to improve the consistency of good effluent
quality. Protection and proper location of mechanical equipment, i.e., rotor
aerators, is necessary in northern climates to minimize icing problems.
Dewatered waste activated sludge from meatpacking waste treatment appears to
have potential as an animal feed supplement.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
rDod processing
Wastewater
Treatment
Sludge
Meatpacking Wastes,
Oxidation Ditch
13/B
*«*«»»««
g7 DISTRIBUTION STATEMEN1
RELEASE TO PUBLIC
19. SECURITY CLASS (This Report)
21. NO. OF PAGES
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123
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22. PRICE
Form 2220-1 (9-73)
111
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