EPA-R 2-73-024
April 1973
Environmental Protection Technology Series
Cannery Wastewater Treatment
with Rotating Biological
Contactor and Extended Aeration
w
\
LU
CD
National Environmental Research Center
Office of Research and Monitoring
U.S. Environmental Protection Agency
Corvallis, Oregon 97330
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RESEARCH REPORTING SERIES
Research reports of the office of Research and
Monitoring, Environmental Protection Agency, have
been grouped into five series. These five broad
categories were established to facilitate further
development and application of environmental
technology. Elimination of traditional grouping
was consciously planned to foster technology
transfer and a maximum interface in related
fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental studies
This report has been assigned to the ENVIRONMENTAL
PROTECTION TECHNOLOGY series. This series
describes research performed to develop and
demonstrate instrumentation, equipment and
methodology to repair or prevent environmental
degradation from point and non-point sources of
pollution. This work provides the new or improved
technology required for the control and treatment
of pollution sources to meet environmental quality
standards.
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EPA-R2-73-024
April 1973
CANNERY WASTEWATER TREATMENT WITH ROTATING
BIOLOGICAL CONTACTOR AND EXTENDED AERATION
by
Max W. Cochrane
Robert J. Burm
Kenneth A. Dostal
National Waste Treatment Research Program
Pacific Northwest Environmental Research Laboratory
200 NW 35th Street
Corvallis, Oregon 97330
Program Element 1B2037
NATIONAL ENVIRONMENTAL RESEARCH CENTER
OFFICE OF RESEARCH AND MONITORING
U.S. ENVIRONMENTAL PROTECTION AGENCY
CORVALLIS, OREGON 97330
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402
Price 90 cents domestic postpaid or 65 cents OPO Bookstore
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ABSTRACT
Fruit and vegetable cannery wastewater was treated during two canning
seasons by two pilot plants of the rotating biological contactor
and extended aeration types.
The objective was to determine the feasibility of these biological
treatments processes on cannery wastewater for the first time in the
United States and to compare the two units under the same operating
conditions. Economics were not included in this study since the
project scope and resources were limited.
Nitrogen and phosphorus were added to the influent wastewater so
the DOB:N:P ratio was kept above 100:5:1.
Both treatment units attained organic removals of over 90 percent.
However, much less detention time was necessary in the RBC to obtain
removals comparable to the extended aeration plant. Sludge produced
by the RBC required additional treatment, but most of the sludge
produced in the extended aeration plant was aerobically digested
in the aeration tank.
Effluent quality from both units was about the same over the operating
temperature range of 10-20°C, although the RBC appeared to recover
more rapidly from organic shock loading. Neither unit produced
an effluent that could be discharged to surface waters without
further treatment.
iii
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CONTENTS
Section Page
I Conclusions 1
II Recommendations 3
III Introduction 5
IV Study Procedures 7
V Results 21
Ml Discussion 37
VLI Acknowledgments 57
Vtll References 59
IX Glossary 61
iv
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FIGURES
Page
1 GENERAL PLAN VIEW OF CANNERY AND PILOT PLANTS . . 8
2 MEA PLAN VIEW 10
3 MEA PHOTOGRAPH 11
4 RBC PLAN VIEW 14
5 RBC PHOTOGRAPH 15
6 MEA R/Le vs TEMPERATURE - 1970 40
7 MEA REMOVAL CHARACTERTISTICS - 1970 41
8 MEA SYNTHESIS AND ENDOGENOUS RESPIRATION COEFFICIENTS -
1970 43
9 RBC REMOVAL CHARACTERISTICS 46
10 RBC AND MEA DETENTION TIME vs COD REMOVAL .... 48
11 MEA AND RBC COD ADDED vs COD REMOVED/HP - DAY . . 49
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TABLES
No. Page
1 Processing and Wastewater Flow Summary-
Flav-R-Pac Cannery 9
2 Average Influent and Effluent Character!stics-
1969 MEA 22
3 Data Summary-! 969 MEA 24
4 Range of Parameters - 1969 MEA 25
5 Average Influent and Effluent Characteristics - 1970 26
6 Data Summary - 1970 MEA 28
7 Range of Parameters - 1970 MEA 29
8 Average Influent and Effluent Characteristics - RBC 31
9 Data Summary - RBC 33
10 Range of Parameters RBC 34
11 RBC and MEA Effluent Solids Concentrations .... 52
12 Organic Overload Recovery Observations - Nov. 10, 1970 54
13 Comparison of Effluents - 1970 56
VI
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SECTION I
CONCLUSIONS
1. The Modified Extended Aeration (MEA) and Rotating Biological
Contactor (RBC) are capable of removing over 90 percent of the
organic matter at COD loadings of 3.1 to 19.1 Ibs COD/day/1,000
cu ft of aeration tank volume for the MEA and 4.4 to 10.6 Ibs
COD/day/1,000 sq ft of disc surface area for the RBC. The upper
loading limit for both units was due to inadequate oxygen addition
equipment. Nutrient addition was made to insure a minimum influent
BOD:N:P ratio of 100:5:1.
2. The RBC removed the same amount of organic matter as the MEA
in a range of theoretical hydraulic detention times (THDT) from
0.17 to 0.42 days for the RBC compared to 7.3 to 75 days for the
MEA.
3. Excluding mixed-liquor suspended solids remaining in the aeration
tank at the end of the canning season, the MEA did not produce
sludge that needed further treatment. The RBC produced sludge
that would require separate digestion facilities.
4. Effluents from both units contained significant suspended
solids. Mhen operated properly, the MEA averaged 72 mg/1, and
the RBC averaged 56 mg/1 during the same time period. However,
the variability of effluent suspended solids was larger for the
RBC.
5. Power requirements for the RBC appeared less than for the
MEA by about a 1:2 ratio. This may be altered considerably under
full-scale operation.
6. The RBC appeared to recover from heavy organic shock loading
in about one day, and the MEA did not appear to recover completely
from the same shock loading for the rest of the study, which was
about two weeks.
7. COD removal for both units was apparently not affected by
mixed liquor temperature in the range of about 10-20°C. Meaningful
data outside this range was not acquired.
8. Nitrification occurred in the MEA but not in the RBC.
9. Both units produced sludge that appeared to have good settling
characteristics. However, limited data were gathered on the RBC.
10. Effluent characteristics were about the same for both units during
good operation.
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SECTION II
RECOMMENDATIONS
1. Since no economic analysis was planned for this study, many
economic questions were left unanswered, however, both treatment
units demonstrated their ability to treat cannery wastewater.
These units are therefore recommended for use in situations where
they are more economical than other methods of treatment. Cost
data may be obtained concerning other applications of the RBC
from Autotrol Corp.
2. In climates associated with driving rain or hail, the RBC
should have a cover that would protect the biological slime and
discs.
3. This study indicates these treatment processes should be used
for pretreatment ahead of municipal or other treatment rather than
for complete treatment.
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SECTION III
INTRODUCTION
PROBLEM
Combined treatment of wastewater from industrial and domestic sources
has generally been looked upon as the most economical approach
to treatment of industrial wastes. Each situation warrants specific
investigation to obtain all the facts necessary to make sound decisions
concerning approach to treatment. Consideration of alternatives
should include at least the following:
1. Combined treatment with the city.
2. Pre-treatment followed by combined treatment.
3. Complete treatment by industry.
Recently a Federal Government policy was established on grants
for construction of domestic wastewater treatment plants. This
policy provides the Environmental Protection Agency the authority
to disapprove construction grant applications by cities that have
not included provisions in their operation and maintenance,schedules
for acceptable industrial wastewater treatment assessment^ '.
As a result of this policy, city officials will feel the need to
evaluate more critically their industrial treatment assessments.
Some industries may also find it necessary to reevaluate the alternatives
in wastewater treatment.
Alternatives 2 and 3 require a detailed look at the treatment processes
available. The following are some of the main points to be considered
in selection of a treatment or pretreatment process:
1. Adequate operation on a seasonal basis.
2. Required operation time and operator skill.
3. Stability under shock hydraulic and organic loads.
4. Stability under widely varying temperature, pH, etc.
5. Available land.
6. Overall economics.
7. Public relations (aesthetic requirements, etc.).
Many of the wastewater treatment processes to be considered have
adequate design information available, and comparisons can be made
quite readily. There are more recent processes that do not
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have enough history of operation available. The Rotating Biological
Contactor (RBC) is a process that does not have readily available
operation and design data. For certain industrial wastes, another
biological process is Modified Extended Aeration (MEA). This process
is a modification of the normal extended aeration process because
the detention is much longer and a relatively new settling device,
the tube settler, is incorporated in the aeration tank thereby
providing close to 100 percent sludge return.
The objective of this study was to determine the effectiveness
of the MEA and RBC processes as means for complete treatment or
pretreatment of cannery wastewater.
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SECTION IV
STUDY PROCEDURES
DESCRIPTION
The study was conducted with two pilot plants which were located
at a cannery owned by United Flav-R-Pac Growers, Inc. at Salem,
Oregon, during the 1969 and 1970 canning seasons. The cannery
processes canned and frozen vegetables and fruits on a seasonal
basis running generally from June through December.
Wastewater for the pilot plants was taken from the cannery discharge
flume just prior to discharge to the city sewage collection system.
The wastewater did not include the initial-wash which contained
large quantities of silt. Normal full-scale biological treatment
processes would be operated in the same manner.
The wastewater was nutrient deficient so ammonium phosphate (9-
30-0) and fertilizer grade urea were added in proportion to influent
wastewater flow. Addition was accomplished in liquid form at a
rate that provided nutrients in the weight ratio of 100:5:1 for
BOD:N:P based on an assumed maximum BOD concentration of 2,000
mg/1.
The wastewater was then pumped to the pilot plants, at as constant
a flow rate as possible, with helical rotor, positive displacement,
variable speed pumps. Effluent from the pilot plants was discharged
to the cannery sedimentation pond. Figure 1 shows the general
layout.
The sedimentation pond is used for settling silt and, other settleable
solids from initial-wash operations. Discharge from the sedimentation
pond goes to a manhole where city personnel measure flow and take
samples for strength determinations to be used for assessment calculations,
Table 1 shows averages of daily wastewater flow measured by the
City of Salem at the sewer manhole that receives the total of discharges
from the sedimentation pond and wastewater flume. The column for
fruit and vegetables processed does not contain a listing of all
items processed during the year indicated. Only the items processed
during pilot plant operation are shown.
Modified Extended Aeration
Figures 2 and 3 show the layout of the MEA pilot plant. The materials
used were:
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Initial-Wash Area
a>
c
c
a
o
o
o
Q_
a:
J3
u.
Sedimentation
Pond
Wastewater Flume
TJ-. -
yibrating
Screens
Sump & Retum\\cjty Sewer
Flow Pump V Manhole
Solid Waste Conveyor
(Cattle Feed)
FIGURE 1. GENERAL PLAN VIEW OF CANNERY AND PILOT PLANTS
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Table 1
PROCESSING AND WASTEWATER FLOW SUMMARY - FLAV-R-PAC CANNERY
1969
1970
Time
Period
8/1-15
8/16-31
9/1-15
9/16-30
10/1-15
10/16-31
11/1-15
11/16-30
12/1-15
1 ?. /I A_^1
Avg. Flow
MGD
0.-857
0. 683
0.873
0.774
1.036
1 062
1. 008
0 R?.l
Vegetable or Fruit
Processed
Corn
Corn, Prunes
Corn, Beets
Beets, Carrots
Carrots
Carrots
Carrots
<~!a VT-nfa
Avg. Flow
MGD
0.750
0.853
0.756
0. 686
0.741
0.795
0.790
0. 626
Vegetable or Fruit
Processed
Beans, Beets
Beans, Beets
Beans, Beets
Beets, Corn,
Squash
Corn, Squash
Corn, Squash
, Corn
Prunes,
, Carrots
, Carrots
Squash, Carrots
Potatos, Squash, Carrots
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Composite
Sampler
(Effluent)
Tube Settler
Module
Inlet at
1/2 Depth
Floating Aerator
(Ihp.)
9 Liquid Depth
I1 Freeboard
12 Sidewall
Height
Influent at Water
Surface Level
ft
Mixed Liquor
Grab Samples
Effluent
Line
Nutrient Addition
Pump a Tank
Pump
^Composite Sampler (Influent)
Flume Stage Recorder
Discharge Flume
Intake.
Wastewater Flume Screen^
J-
To Sediment
k
^
c
M<
ation
Por
City
>ewer
anhole
FIGURE 2. MEA PLAN VIEW
10
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FIGURE 3. MEA PHOTOGRAPH
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Tank - bolted 14 Ga. aluminum corrugated plates.
Tank liner - 1/16" thick butyl rubber
Settling unit - Neptune Microfloc tube settler - 2' depth x
2-1/21 width x 5' length module; tube inclined
60° to horizontal plane.
Aerator - 1 Hp. Welles floating aerator.
The aeration tank was placed with 2 feet of the aluminum sidewalls
below ground level.
Flow to the MEA was controlled by adjusting the speed of the influent
pump until the desired flow was obtained in the inlet flume or
by changing the overflow weir height in the influent flume and
allowing the excess influent to be bypassed to the sedimentation
pond. The actual stage in the flume was recorded continuously
with a Type F Stevens water level recorder. The intake on the
pump suction line was a 1-1/2" diameter PVC plastic pipe section
2 feet long. The pipe was perforated by drilling 3/16" holes at
about 1" spacing. Flow in the cannery wastewater flume was intermittent
due to equipment breakdown and shutdown on weekends. To insure
automatic influent pump operation in response to wastewater flow
on an "on-off" basis, a float switch was installed in the pump
control circuit.
Nutrient addition was accomplished in liquid form with a chemical
proportioning pump and a 50 gallon mixture tank. Feed rate
was manually changed except for automatic shutoff when wastewater
flow ceased.
Aeration was provided by a 1 horsepower floating aerator that was
designed to keep suspended solids in the tank in suspension as
well as provide the oxygen needed for biological treatment of the
wastewater. The aerator was operated continuously except for a
few shutdowns with a maximum of 30 minute duration due to overloaded
electrical control circuits.
Sludge settling and return to the aeration tank were accomplished
as the mixed liquor passed upward through the tube settler module.
The settleable solids slid down the tube settler surfaces and were
swept back into the aeration tank by the mixed liquor flow past
the bottom of the module. Clarified liquid continued to the water
surface level of the module, where it entered the effluent line
by passing over two multiple v-notch weir plates each of which
was 5' long.
12
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Rotating Biological Contactor
Figure 4 shows the layout of the RBC pilot plant. Figure 5 shows
a photograph, from Autotrol Corp., of the type of RBC that was
used. However, the unit used in this study had a fiberglass canopy
for protection of the biological mass on the discs from driving
rain. The RBC was built and provided by Autotrol Corporation,
Milwaukee, Wise., as a pilot plant model.
Flow of wastewater was controlled by adjusting the speed of the
influent pump until the desired stage was obtained on the influent
v-notch weir. The wastewater was taken in through the same type
intake as used in the MEA, and then it was pumped to the primary
clarifier. Effluent from the primary clarifier flowed by gravity
to the RBC where measurement of flow was made with a Type F Stevens
level recorder mounted behind the influent v-notch weir. Automatic
pump control was provided by the same float switch as used for
the MEA.
Primary clarification of the wastewater was provided on the recommendation
of Autotrol Corp. representatives. This was accomplished with
a 2'-diameter upflow clarifier. The surface over-flow rate was 920
gal/sq ft/day at a wastewater flow-of 2 gpm, and the THDT was 51
minutes, which is based on an overall clarifier volume of 12.3
cu ft. The THDT was usually much less than 51 minutes because
of the volume occupied by settled solids.
The nutrient addition mixture was the same as for the MEA. However,
gravity flow was used from an elevated, constant-head, tank with
a 30 gallon capacity. The flow was manually controlled, and the
nutrient addition was made in proportion to influent flow. Addition
was made just ahead of the inlet to the RBC influent chamber.
As the flow entered the influent chamber, rotating cups elevated
the wastewater and nutrient mixture to the influent channel to
the first disc stage. The flow entered on one side of the first
stage and left on the diagonal corner to the influent channel of
the second stage. The same flow pattern was repeated through the
second stage to the secondary clarifier. Flow into the secondary
clarifier was dampened by a baffle over the end of the influent
pipe.
Settled sludge was picked up in the secondary clarifier by a rotating
sludge scraper operated at about 4 revolutions per hour. The scraper
emerged from the clarifier on the side of the RBC opposite the
effluent weir which minimized the carry over of settled sludge
in the effluent. The sludge then flowed by gravity to the cannery
sedimentation pond.
Effluent from the secondary clarifier was discharged to the sedimentation
pond by passing over a multiple v-notch weir plate that was the
same length as the secondary clarifier.
13
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Discharge Flume
Q)
Composite Sampler
x
Effluent weir
Sludge Scraper Arm
Primary
/^Clarifier
Influent
hamber
To Sedimentation Pond
RBC
Nutrient
Addition
Tank.
Influent Control ft
,-~«--^ [ ^[t^-Measurement Chamber
Q -» mzzn^tt^-\i-Notch Weir
Wejr stage Recorder
Intake
Screen
FIGURE 4. RBC PLAN VIEW
14
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FIGURE 5. RBC PHOTOGRAPH
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Aeration in the two disc stages was directly related to the rotation
speed of the discs which was fixed at about 4 rpm. There were
a total of 91 discs in the two stages. Each disc was 7/16" thick
and 5.35" in diameter. The discs were made of molded polystyrene
supported by radial metal braces. Without any growth on the discs,
the total disc surface area was 4,670 sq ft. The total submerged
surface area was about 1,500 sq ft, depending on flow rate through
the unit.
OPERATION
MEA Start-up-1969
The MEA was started August 22, 1969, by seeding the aeration tank
with 20 gallons of digestor sludge from the City of Con/all is Sewage
Treatment Plant.
Wastewater flow to the MEA was started August 26 at 0.5 gpm after
the tank was filled to the effluent weir level with water from
the fresh water supply at the cannery. The flow was increased
gradually from 0.5 gpm to 2.0 gpm in about a week which was the
average flow rate throughout the study, and nutrient addition was
started on the second day of this acclimation period.
MEA Start-up-1970
The 1970 pilot plant operation was begun on July 13, by filling
the MEA with water from the fresh water supply at the cannery.
Seeding was accomplished by adding 15 gallons of activated sludge
mixed liquor from the City of Dallas, Oregon, wastewater treatment
plant, which treats cannery wastewater jointly with the domestic
wastewater.
Wastewater influent to the MEA was started on July 13, at about
1 gpm, and the flow was gradually increased until July 18, when
it was 2.0 gpm. This flow rate was maintained until July 24, when
it was increased to 4.0 gpm in an attempt to increase the MLSS
more rapidly. The influent pump was set for 4.0 gpm but actual
flow was about 2.5 gpm due to plugging of the intake.
On July 24, a microscopic observation was made on a sample of the
MEA mixed liquor. There were ciliates, rotifers, and motile bacteria,
and there appeared to be a small number of each, although actual
counts were not made.
Nutrient addition was made with the same equipment and feed rates
as in 1969, and it was begun at the same time as the seed addition.
16
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RBC Start-up-1970
The RBC did not arrive on the site until August 24 and all supporting
equipment was not operating properly until about September 10.
No seed was applied to the RBC before adding wastewater. Flow
of wastewater was started to the empty unit on August 26, at a
rate of about 2 gpm. Nutrient addition was started on August 28,
at the same concentration and rate as to the MEA. Wastewater and
nutrient flow was unsteady during the start-up period, but a biological
mass appeared on the discs by August 31, and an improvement in
the physical appearance of the effluent was also noted. Unsteady
conditions resulted from intermittent wastewater flow and plugged
intake on several occasions. Because of the unsteady start-up
conditions, sampling on the RBC was not begun until September 14.
The disc rotation speed was about 4 rpm, and the sludge scraper
rotation speed was about 4 rph.
MEA Sampling Procedure and Analyses - 1969 and 1970
During both seasons, the same approach to sampling was used on
the MEA. Influent and effluent samples were taken by automatic
composite samplers from points 1 and 2 shown on Figure '2 on a 24-
hour basis. The composite samplers were started at about 9:00
am on Monday and Thursday of each week, and they sampled about 10
seconds out of every 20 minutes automatically for 24 hours. Pumping
rate with the composite samplers on any given sample day was constant
because the wastewater flow was constant.
Grab samples were taken for mixed liquor analysis from the point
indicated on the side of the MEA in Figure 2. During 1969 samples
were taken on a random basis, but during 1970 samples were taken
each day except on weekends. These samples were only analyzed
for settleable solids on a volumetric basis on Monday, Wednesday,
and Thursday. On Tuesday and Friday, samples were analyzed for
settleable solids, SS, VSS, and oxygen uptake.
The following on-site analyses were performed on the mixed liquor:
dissolved oxygen, settleable solids, temperature, and oxygen uptake.
Dissolved oxygen and temperature were measured with a Yellow Springs
Instrument Co. dissolved oxygen probe; settleable solids was measured
volumetrically with a glass 1,000 ml graduated cylinder; and oxygen
uptake was measured with a YSI dissolved oxygen stirrer combination
probe inserted in a BOD bottle which was held at constant temperature.
At the Pacific Northwest Water Laboratory the following analyses
were performed on the mixed liquor grab samples: suspended solids,
17
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volatile suspended solids, pH, total alkalinity, oxygen uptake,
and filtered and unfiltered COD during the endogenous phase of
plant operation.
Composited MEA influent and effluent samples were analyzed for
the following at the Pacific Northwest Water Laboratory: filtered
and unfiltered BOD and COD, suspended solids, volatile suspended
solids, pH, total alkalinity, ammonia nitrogen, nitrate nitrogen,
nitrite nitrogen, total Kjeldahl nitrogen, total phosphorus and
ortho-phosphates.
RBC Sampling Procedures and Analyses -1970
Influent samples for the RBC were the same samples as taken for
the MEA. Effluent samples were taken each week from the RBC by
automatic composite samplers on a 24-hour basis, from about 9:00
am Monday to 9:00 am Tuesday and from about the same time Thursday
to Friday. As with the MEA, the sampler was set to pump at a constant
rate on any given sample date.
Grab samples were taken from the mixed liquor of the first and
second disc stages on Tuesday and Friday. The samples were taken
by inserting a siphon hose (1/2" inside diameter) about 18" below
the water level along the side of each stage between the rotating
discs and tank side. The hose was moved the entire length of the
stage during the siphoning in an attempt to get representative
samp! es.
The slime thickness and texture were so variable on the discs that
the only attempt to determine the amount of biomass was an overall
visual estimation of average slime thickness for each stage of
discs. Samples of sludge from the secondary clarifier were obtained
by diverting sludge flow from the removal scraper to a 35 gallon
tank. This capacity tank allowed about a 1 hour continuous sample
to be taken. The tank contents were thoroughly mixed by gently
hand stirring, and two 1,000 ml samples were taken for analysis.
On-site analyses for the RBC were as follows: dissolved oxygen,
temperature, and slime thickness. Slime thickness was obtained
by visual estimation based on only a few random measurements each
day. Dissolved oxygen and temperature were obtained in the mixed
liquor of the disc stages and the secondary clarifier by measurement
with a YSI dissolved oxygen probe.
The same analyses were made on the RBC effluent in the Water Laboratory
as for the MEA influent and effluent.
Disc stage mixed liquor grab samples were analyzed for suspended
solids and volatile suspended solids after the samples were homogenized
in a blender.
18
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Secondary clarifier sludge samples were also homogenized and analyzed
for suspended solids and volatile suspended solids. Settleable
solids were run on unblended samples at the laboratory using a
1,000 ml graduated cylinder and gravimetric suspended solids analysis,
Settleable solids were run on unblended samples.
MEA and RBC - Methods of Analysis
Analyses were performed according to Standard Methods^' with the
exceptions of ammonia, nitrate, nitrite, total Kjeldahl nitrogen,
total phosphorus, orthophosphates, and suspended and settleable
solids which were all analyzed according to FWPCA'3) methods.
MEA and RBC - Sample Preservation
All samples for laboratory analysis were collected in insulated
and iced containers and were transported under the same conditions.
At the laboratory, samples were split into portions to be analyzed,
preserved with mercuric chloride solution or sulfuric acid and
then stored at 4°C, according to- FWPCA^ ' preservation methods.
Samples that were not to be preserved were stored at 4°C until
they were analyzed, which was the same day as sampling for about
95 percent of the samples.
19
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SECTION V
RESULTS
MEA-1969
Summaries of data for the MEA during 1969 are presented in Tables
2 and 3, and ranges for the same parameters are shown in Table
4.
All values shown in Tables 2, 3, and 4 are in mg/1 unless otherwise
noted. Theoretical hydraulic detention time is calculated by using
influent flow and an aeration tank volume of 32,500 gallons.
The influent values shown in Tables 2,3, and 4 are based on samples
of wastewater pumped from the cannery wastewater flume shown in
Figure 1. Until the latter part of October, 1969, the initial-
wash wastewater was not included in this flume because it was discharged
directly to the sedimentation pond. At the end of October, however,
the initial-wash wastewater was routed through the flume to the
city sewer because the sedimentation pond was filled with silt.
As a result, influent SS values and other parameters reflected
the effect of the silt-laden initial-wash wastewater during the
latter part of the season.
Sludge volume index was run on the MEA during 1969, but all values
exceeded 300.
Nutrients were added ahead of the influent sampling point so all
influent nutrient data in Table 2 were combined concentrations of
wastewater and nutrients added.
The tube settler SS removal efficiency ranged from 6.6 to 84.8
percent with an average of 55 percent, and for VSS the range was
7.0 to 85.4 and the average was 55 percent.
MEA-1970
Summaries of data for the MEA during 1970 are presented in Tables
5 and 6, and ranges are presented in Table 7.
All values shown in Tables 5, 6, and 7 are in mg/1 unless otherwise
noted. Theoretical hydraulic detention time was calculated in
the same manner as in 1969. The values shown for December are
for endogenous respiration since influent flow was stopped on November
24, which was essentially the end of the canning season.
21
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Table 2
AVERAGE INFLUENT AND EFFLUENT CHARACTERISTICS - 1969 MEA
ro
ro
Time
Period
9/1-15
9/16-30
10/1-15
10/16-31
11/1-15
11/16-31
12/1-15
12/16-31
Flow
gpm
2.1
1.2
2.2
2.9
2.6
__-
D.T.
days
10.8
18.9
10.3
7.8
8.7
(3)
Temp.* BOD
°C Inf. Eff.
16.0
14.0 50
10.5 620 1KO
11.5 470 130
11,5 - -
10.0 650 40
9. 0 520 20
7.0 720
(3)
COD (Total)
Inf. Eff.
2390
1360
1090
720
320
980
820
1040
210
180
530
280
290
150
100
(3)
COD (Soluble)
Inf. Eff.
170
90
100
90
70
70
50
Inf.
430
260
140
450
340
740
___
(3)
SS
Eff.
100
190
340
270
150
190
Inf.
400
240
130
130
40
170
-
(3)
vss
Eff.
90
150
320
190
60
70
___
___
Inf.
6.2
4.4
5.6
6.2
6.5
6.1
6.9
7.7
(1)
oH
Eff.
6.9
7.2
6.6
6.6
7.4
7.5
7.6
8.2
Inf.
17
41
32
33
47
69
66
336
(2)
A1K
Eff.
78
141
83
113
215
395
521
654
* Mixed liquor temp.
(1) Median value
(2) As calcium carbonate, mg/1
(3) Concentration in mg/1
-------
Table 2 (Continued)
(6)
Time
Period
9/1-15
9/16-30
10/1-15
10/16-31
11/1-15
11/16-30
12/1-15
12/16-31
(4)
TKN
Inf.
96.8
47.9
55.5
47.2
60.4
188
42.0
300
Eff.
18.2
53.6
55.6
46.0
94.0
140
130
170
(4)
Ammonia-N
Inf. Eff.
7.2
7.0
1.0
6.4
40.0
280
48.4
3.8
22.4
12.8
5.4
70.4
100
124
.156
(4)
Nitrate-N
Inf. Eff.
0.12 0.
0.12 0.
0.
0.
0.
1.
0.
12
06
53
65
12
10
.__
28
(4)
Nitrite-N
Inf. Eff.
0.04 0.03
0.01 0.02
0.89
0.21
1.44
4. 60
1.76
3.52
(5)
Total-P
Inf.
15.5
13.5
6.0
48.6
9.1
55.7
13.7
10.3
Eff.
3.2
8.3
10.0
4.9
14.3
16.7
18.8
27.0
(5)
Ortho-P
Inf.
6.70
8.35
2.25
48.7
51.4
13.8
270
4.74
Eff.
1.70
7.05
3.85
1.58
11.30
15.6
18.4
25.8
(4) As nitrogen, mg/1
(5) As phosphorus, mg/1
(6) Nutrient addition made before influent sampling point
-------
Table 3
DATA SUMMARY - 1969 MEA
Loading Ratios and Removals
Mixed Liauor
Time
Period
9/1-15
9/16-30
10/1-15
10/16-31
11/1-15
ro
"** 11/16-30
12/1-15
12/16-31
1/1-15
1/16-30
(3)
MLSS
144
508
360
543
492
1020
618
633
536
592
(3)
MLVSS
136
462
302
340
208
345
277
322
250
247
(1)
PH
6.8
7.2
6.4
6.5
7.3
7.6
7.7
8.2
8.2
7.6
(2)
A1K
560
150
80
117
265
413
525
625
540
280
Temp.
°C
16.0
14 0
10.5
11.5
11.5
10.0
9.0
7.0
6.0
6.0
#COD #COD Inf. %
(3) Day Day BOD BOD
DO #MLVSS 1000 Cu. Ft. COD Removal
5.0
5.0 0.20 4.8
5.5 0.33 7.1 0.57 73
5.0 0.29 7.0 0.65 72
8.0
6.0 -- 0.66 94
8.0 0.63 96
7.5 0.69
8.0
8.0
CODT SS VSS
Removal Removal Removal
91 77 77
87 27 27
51 Increase Increase
61 40 Increase
9 56 Increase
85 74 59
88
__
__
(1) Median value
(2) As calcium carbonate, mg/1
(3 ) Concentration in mg/1
-------
Table 4
RANGE OF PARAMETERS 1969 MEA
Parameter
BOD
COD (Total)
COD (Soluble)
SS
VSS
pH
A1K
TKN
Ammonia -N
Nitrate-N
Nitrite-N
Total-P
Ortho-P
Flow (gpm)
D.T. (days)
BOD/CODT
DO
Temp. °C
#COD/Day/#MLVSS
#COD/Day/1000 Cu.
Inf.
12-1640
43-2760
69-2140
16-448
3. 9-7.7
1-336
1. 9-1390
0. 52-280
0. 12*
0. 01*
1. 8-170
1. 2-270
0-6.0
>-3.7
0. 19-0. 73
i
Ft. ---
Eff.
9-264
57-628
15-222
24-516
24-464
6. 3-8. 2
41-654
15. 9-170
0. 28-156
0. 03-1. 1
0.008-4.6
2. 6-27.0
0. 23-25. 8
Mixed
Liquor Removal (%)
40.6-99.9
10.0-93.8
18-818 0-77
13-786 0-77
6.2-8.3
40-668
3.5-8.5
6-18
0.003-1.80
0.06-18.4
* (only data)
Units in mg/1 except where otherwise indicated
25
-------
Table 5
AVERAGE INFLUENT AND EFFLUENT CHARACTERISTICS - 1970 MEA
ro
Time
Period
8/1-15
8/16-31
9/1-15
9/16-30
10/1-15
10/16-31
11/1-15
11/16-30
12/1-15
12/16-31
Flow
gpm
2.0
2.4
1.4
1.7
2.4
2.0
1.5
1.3
D.T.
days
11.5
9.3
16.4
13.3
9.5
11.3
15.6
17.1
Temp.*
°C
20.0
18.5
16.0
15.0
13.5
10.0
11.0
8.0
5.5
3.0
(3)
BOD
Inf.
1290
1090
1100
1050
750
750
810
Eff.
90
80
150
100
80
60
200
(3)
COD (Total!
Inf. Eff.
770
1510
1800
1200
1580
1550
1060
1630
60
160
130
140
110
120
270
510
___
(3)
COD (Soluble)
Inf. Eff.
1230
1220
840
1050
810
800
1330
100
90
80
70
70
150
250
___
(3)
SS
Inf.
150
170
460
230
480
790
300
330
___
Eff.
60
50
70
70
80
70
180
360
___
(3)
vss
Inf.
80
160
420
200
410
540
210
180
___
Eff.
40
45
55
65
70
60
150
300
(1)
oH
Inf.
6.8
5.6
5.7
6.5
6.1
6.0
5.9
5.5
Eff.
6.3
6.5
5.8
5.8
6.1
5.8
6.4
6.7
___
(2)
A1K
Inf.
40
25
41
70
48
40
30
43
Eff.
25
40
18
17
25
15
60
60
~
* Mixed liquor
(1) Median value
(2) As calcium carbonate, mg/1
(3) Concentration in mg/1
-------
Table 5 (Continued)
Time
Period
8/1-15
8/16-30
9/1-15
9/16-30
10/1-15
-j
10/16-31
11/1-15
1 1 /i<:_an
(4)
TNK
Inf.
16.8
27.1
38.4
21 .-6
25.4
28.5
17.4
OA a
Eff.
50.6
24.9
18.2
36.2
31.8
18.3
34.2
me -7
(4)
Ammonia-N
Inf.
0.8
1.7
1.8
0.8
0.9
1.2
1.1
O Q
Eff.
45.5
15.0
16.7
22.5
7.9
7.3
15.6
It C
(4)
Nitrate-N
Inf.
0.26
0.97
0.71
0.17
0.37
0.17
0.28
n c"7
Eff.
3.90
3.22
0.93
7.73
0.08
1.14
1.21
(4)
Nitrite-N
Inf.
0.04
0.04
0.14
0.01
0.08
0.03
0.05
n rvr
Eff.
42.00
14.45
6.85
9.30
2.35
10.98
6.90
(5)
Total-P
Inf.
2.1
5.7
5.3
3.9
2.9
3.3
2.3
lie
Eff.
20.7
20.0
32.3
43.5
36.9
35.5
29.9
ca >
(5)
Ortho-P
Inf.
1.07
4.85
4.48
3.30
3.45
2.40
1.29
fi M
Eff.
17.8
18.0
30.3
43.3
36.3
37.1
24.5
4.7 a
(4) As nitrogen, mg/1
(5) As phosphorus, mg/1
(6) Nutrient addition made after influent sampling point
-------
Table 6
DATA SUMMARY - 1970 MEA
Loading
Ratios and Removals
Time
Period
8/1-15
8/16-31
9/1-15
CO 9/16-30
10/1-15
10/16-31
11/1-15
11/16-30
12/1-15
i o /1 G. ai
(3)
MLSS
320
670
1070
1230
1920
2300
2170
1280
1090
ocn
(3)
MLVSS
210
490
880
1060
1850
2000
1890
1020
«in
Mixed :
(1)
pH
6.6
5.5
6.2
S.7
6.3
6.6
6.6
. 4
K n
Liauor
(2)
A1K
--
64
37
27
22
20
91
63
aa
Temp.
°c
20.0
18.5
16.0
15.0
13.5
10.0
11.0
8.0
a n
(3)
DO
3.1
2.7
3.4
3.4
1.8
4.0
1.8
3.9
83
1 7
#COD
Day
#MLVSS.
0.328
0.215
0.144
0.084
0.102
0.090
0.040
0.082
#COD
Day
1000 Cu Ft
6.62
8.25
8.93
6.23
12.25
9.74
5.19
6.49
Inf.
BOD
COD
0.85
0.61
0.92
0.66
0.48
0.71
0.51
%
BOD
Removal
93
93
86
91
89
92
75
%
CODT
Removal
92
89
93
88
93
92
75
69
%
CODS
Removal
92
93
90
93
91
81
81
«
SS
Removal
60
71
85
70
83
91
40
Increase
%
VSS
Removal
50
72
87
68
83
88
29
Increase
(1) Median value
(2) As calcium carbonate, tng/1
(3) Concentration in mg/1
-------
Table 7
RANGE OF PARAMETERS - 1970 MEA
Parameter
BOD
COD (Total)
COD (Soluble)
SS
VSS
PH
A1K
TKN
Ammonia -N
Nitrate-N
Nitrite-N
Total-P
Ortho-P
Flow (gpm)
D.T. (days)
BOD/CODT
DO
Temp. °C
# COD /Day /#MLVSS
#COD/Day/1000 Cu.Ft
Inf.
371-1740
636-3000
419-1950
85-2400
60-1560
5. 0-6. 8
21-62
10. 7-58. 0
0. 16-5. 1
0. 042-1. 68
0. 002-0. 20
1.38-21.6
0.3-10. 9
0.3-3. 1
75.0-7. 3
0. 56-0.90
~ "" ~" \
Eff.
57-198
80-708
41-324
32-505
22-385
5. 6-6. 8
8-102
9.4-120
0. 13-117
0. 008-20. 2
0. 018-43.5
16. 0-60. 0
1. 6-48.4
Mixed
Liquor Removal (%)
76-96
47-97
204-2560 40-91
132-2210 29-88
5. 5 7. 0
14-168
0.2-6.8
2.0-20.0
0.03-0.69
3.1-19.1
Units in mg/1 except where otherwise indicated
29
-------
The influent data shown in Tables 5 through 10 are based on samples
taken from the cannery wastewater flume shown in Figure 1. Since
the wastewater from the initial-wash area never passed through
this flume during the 1970 season, the samples are representative
of actual operating conditions that would be encountered by full-
scale biological treatment plants. The silt-laden wastewater
from initial-wash would considerably change the concentration of
suspended solids and other parameters of the overall wastewater
as it did during the latter part of the 1969 season.
Sludge volume index ranged between 19 and 179 with a median value
of 81.
Influent nutrient data in Table 5 were actual wastewater characteristics
before nutrient addition. Nitrogen and phosphorus are covered
in more detail in the Discussion section.
SS tube settler efficiency ranged from 61-97 percent and averaged
90 percent and for VSS the range was 62-97 percent with an average
of 90 percent.
RBC-1970
Summaries of data for the RBC during'1970 are presented in Tables
8 and 9, and ranges are presented in Table 10.
All values shown in Tables 8, 9, and 10 are in mg/1 unless otherwise
indicated. Detention time shown was based on theoretical figures
furnished by Autotrol Corporation, although check calculations
were made so any large errors would be eliminated. The detention
times included the effect of wastewater displacement by the various
thicknesses of the disc slime layer and the volume of the secondary
clarifier. Detention time in the disc stages ranged from 1/3 to
1/2 of total detention time through the RBC. Dissolved oxygen
in the secondary clarifier was usually zero as a result of the
length of detention time in this portion of the unit.
Average disc slime thickness was 3/16" with the exception of the
time periods 9-1 to 9-15-71 and 10-1 to 10-15-71, when the average
thickness was 1/8". These values are approximate since only visual
observation was considered practical due to the slime variability.
Loading was based on total COD applied per 1,000 square feet of
disc surface.
No attempt was made to estimate the quantity of sludge synthesized
because of the need for a much more rigorous sampling program,
which was beyond the limitations of this study. The solids values
presented in Table 9 are intended for use in rough solids production
calculations only.
30
-------
Table 8
AVERAGE INFLUENT AND EFFLUENT CHARACTERISTICS - RBC
Time
Period
9/1-15
9/16-30
10/1-15
10/16-31
11/1-15
11/16-30
Flow
gpm
2.0
2.0
1.6
1.9
2.1
1.6
D.T.*
days
0.20
0.20
0.28
0.23
0.19
0.28
u
Temp.
°C
15.0
13.5
11.0
10.5
12.0
(3)
BOD
Inf.
1090
1100
1050
750
750
810
Eff.
65
165
240
100
240
(3)
COD (Total)
Inf. Eff.
1800
1200
1580
1550
1060
1630
130
160
230
310
120
320
(3)
COD (Soluble)
Inf. Eff.
1220
840
1050
810
800
1330
130
100
160
250
100
210
(3)
ss
Inf.
460
230
480
790
300
330
Eff.
10
40
100
80
35
90
(3)
vss
Inf.
420
200
410
540
210
180
Eff.
10
40
70
75
32
85
(1)
pH
Inf.
5.7
6.5
6.1
6.0
5.9
5.5
Eff.
8.0
8.0
8.0
7.8
7.7
7.7
(2)
A1K
Inf.
41
70
48
40
30
43
Eff.
372
705
400
240
250
268
* DT for entire RBC including secondary clarifier
# Average for both disc stages
(1) Median value
(2) As calcium carbonate, mg/1
(3) Concentrations in mg/1
-------
Table 8 (Continued)
(6)
Time
Period
9/1-15
9/16-30
10/1-15
10/16-31
11/1-15
11/16-30
(4)
TKN
Inf.
38.4
21.6
25.4
28.5
17.4
24.3
Eff.
145
239
98.3
73.2
70.5
71.9
(4)
Ammonia-N
Inf. Eff.
1.8
0.8
0.9
1.2
1.1
2.9
6.4
161
82.3
52.6
55.7
72.0
(4)
Nitrate-N
Inf.
0.71
0.17
0.37
0.17
0.28
0.57
Eff.
0.11
0.13
0.10
0.14
0.04
0.05
(4)
Nitrite-N
Inf.
0.14
0.01
0.08
0.03
0.05
0.07
Eff.
0.02
0.01
1.39
0.01
0.01
0.02
(5)
Total-P
Inf.
5.3
3.9
2.9
3.3
2.3
11.5
Eff.
44.0
41.6
31.6
16.9
16.0
18.8
(5)
Ortho-P
Inf.
4.48
3.30
3.45
2.40
1.29
6.61
Eff.
46.2
50.0
30.2
20.2
14.8
18.0
(4) As nitrogen, mg/1
(5) As phosphorus, mg/1
(6) Nutrient addition made after influent sampling station
-------
Table 9
DATA SUMMARY - RBC
Secondary
Clarifier Sludee
Time
Period
9/1-15
9/16-30
10/1 -IS
oo 10/16-31
11/1-15
11/16-30
(1)
SS
1240
1040
1640
1500
3600
(1)
vss
1140
920
1540
1290
2770
%
Sett.
Solids
19
14
30
25
54
DO*
S.O
3.2
1.9
2.3
2.5
2.0
Mixed
Temp.
°C
15.0
13.5
11.0
10.5
12.0
Liquor
1st
Stage
MLVSS
800
482
775
1420
2nd
Stage
MLVSS
1960
1030
740
1100
Loading
#COD
Day
lOOOSq.Ft.
7.20
6.00
6.10
7.10
5.70
8.10
Inf.
BOD
CODT
0.61
0.92
0.67
0.48
0.71
0.50
%
BOD
Removal
94
84
68
87
70
Ratios and
%
CODT
Removal
93
87
85
80
89
80
Removals
%
CODS
Removal
89
88
85
69
87
94
*;
SS
Removal
98
83
79
90
88
73
%
VSS
Removal
98
80
83
86
85
53
* Average DO for both disc stages* mg/1
# Average temperature for both disc stages
(1) Concentration in mg/1
-------
Table 10
RANGE OF PARAMETERS - RBC
Parameter
BOD
COD (Total)
COD (Soluble)
% Settleable Solids
SS
VSS
MLVSS- 2nd Disc stage
PH
A1K
TKN
Ammonia -N
Nitrate-N
Nitrite -N
Total- P
Ortho-P
Flow (gpm)
D. T. (days)
BOD/CODT
DO
Temp. °C
#COD/Day/1000Sq.Ft
Inf.
371-1330
636-3000
419-1950
--
153-2400
100-1560
--
5. 0-6. 8
22-62
10.7-58.0
0. 6-5. 1
0. 04-0. 80
0.002-0. 16
1.38-21. 6
0.48-10.9
0. 8-2. 5
0.42-0. 17
0.56-0.83
--
--
Mixed Clarifier
Eff. Liquor Sludge
65-405
59-898
46-806
4.0-78.0
12-145 -- 150-4850
11-130 170-1460* 380-3800
410-1960
6.4-8.6
132-1040
19.5-560
6.4-220
0.03-0.25
0.001-0.029
12.0-60.0
7.56-57.8
__
__
__
0.6-5.0
10.0-19.0
4.4-10.6
Removal
71-92
64-98
--
--
56-99
56-98
--
--
--
--
--
--
--
--
--
--
--
--
--
--
* 1st Disc Stage
Concentrations in mg/1 unless otherwise indicated
34
-------
The dissolved oxygen and temperature values in Tables 8 and 9 are
combined average values for the mixed liquor of both disc stages.
Influent nutrient data in Table 8 were actual wastewater characteristics
before nutrient addition.
35
-------
SECTION VI
DISCUSSION
MEA
Various attempts were made to use existing kinetic equations for
the MEA. The first attempt was made.using the relationship for
reaction rate as expressed by Monod^ in equation (1):
FL
0)
where reaction rate is determined by equation (2):
R = ihr (2)
V
R = reaction rate = rate of waste utilization per unit of
time and biological mass. (#COD Removed/#MLVSS/Day)
F = maximum possible reaction rate (at high waste concentration).
C = soluble waste concentration (BOD or COD) at 1/2 F.
L = substrate concentration = effluent soluble BOD or COD (for a
completely mixed system).
L = substrate added = influent total COD or BOD (if all suspended
volatile matter is assumed biodegradeable).
S = mixed liquor suspended volatile solids (assumed to be directly
proportional to active biological mass).
t = hydraulic detention time.
Equation (1) was intended for sysitems with any range of effluent substrate
concentrations relative to C. For this reason the first attempt at kinetic
evaluation was made with this approach. Soluble COD levels were as high
as 125 mg/1 during this study.
The Monod approach involved the following steps:
37
-------
1. The basic Monod equation was rearranged and a temperature
correction applied to form the following equation:
(F20)(6T-20)Le
-J2-R - - = C + Le (3)
where:
F2Q = F at 20° C
9 = temperature correction coefficient.
T = aeration tank temperature in °C.
Equation (3) was further modified to:
Le _ , x, C
_ __
R(62°-T) " e F20
which can be plotted as a straight line equation of the form
y = mx + b.
2. Analytical measurements and calculations gave L > R, and
T for the various sampling days.
3. 9 values between 1.0 and 1.40 were assumed and, with the
use of a computer, least square lines and correlation coefficients were
calculated using the L , R, and T values together with the various
assumed 9 values.
4. The optimum correlation coefficient was determined to be 0.66
and the corresponding 9 value was 1.130.
5. F?n and C were then determined by using the 9 value of 1.130
and equation (4).
\
F?n was found to be 0.3 which does not seem to be a reasonable value
based on grange of 4 to 24 IBS COD removed/LB MLVSS-Day reported by
McCartyA ' There may be several factors contributing to such a low
value for F?n in this study, but the largest factor is probably the
large sludgeuage, which is about 200 to 300 days. Active biological mass
would undoubtedly be only a small percentage of MLVSS at these sludge
ages. And if true values for active mass were used in equation (2)
for calculating reaction rate, larger values of F2Q would result.
A second attempt at kinetic evaluation involved another approach that
has been used often in the past. Despite the relatively high observed
L values, L was assumed to be much less than C so that (C + L ) in
tne denominator of the right hand side of equation (1) was essentially
equal to C and the following equation resulted:
38
-------
R - IT Le = KLe
(5)
where
K = a constant
Equation (5) was then modified to include a temperature correction factor:
R . » «T-20
(6)
where
K2Q = K at 20°C = a constant
9 = temperature correction coefficient.
Figure 6 is a semi-log plot of R/L against aeration tank temperature.
A least square line was calculates for the data points shown, and a
of 0.00276 and a temperature coefficient of 1.107 were obtained.
se values were reasonable, but the correlation coefficient was 0.51
so confidence in this approach was not very great.
The third evaluation approach of the MEA involved a simple comparison,
as shown in Figure 7, of influent COD loading and COD removal. Total
influent COD minus soluble effluent COD was used for calculation
of removal rate. The least square line in Figure 7 shows the removal
rate as a function of influent COD rather than effluent soluble
COD, as is more often the case.
The data were gathered over a range of 6°C, and the high correlation
coefficient suggests a temperature coefficient of 1.0 in this range.
Detention time varied from 8.7 to 17.4 days while mixed liquor
suspended solids increased from 400 to 2,000 mg/1 during the period
shown.
In view of the wide range of variables, the excellent correlation
is very encouraging. Restriction in aeration capacity prohibited
higher loading rates so the point of nonlinear relationship between
removal rate and loading was not (determined.
Sludge production and endogenous respiration coefficients were
determined for the MEA by the following procedure:
1. All influent VSS were assumed to be biodegradeable and
therefore, to have no influence on changes in MLVSS concentration.
2. The change in quantity of VSS in the aeration tank between
sampling days was assumed to be due to sludge synthesis, endogenous
respiration, and solids wash-out in the effluent.
39
-------
o>
0.001
0.0005
o.oooi
r- = (.00276)(I.I07T"2°)
Le
"r" = 0.51
I
5 10 15 20
TEMPERATURE (°C)
FIGURE 6. MEA R/L VS TEMPERATURE - 1970
C
40
-------
0.30
01
LU
Q_
0.20-
GO
DO
_l
I
Q
UJ
O
2
UJ
Q
O
O
0.10
TEMP: i2.5-i8.5°c
DATE :8-l8 -10-25-70
I
I
1
Y = 0.98 X + 0.003
1
0 0.10 0.20 0.30
TOTAL COD APPLIED-LBS/LB MLVSS PER DAY
FIGURE 7. MEA REMOVAL CHARACTERTISTICS - 1970
-------
3. Measured values for daily sludge production were plotted
against daily COD removal as shown in Figure 8.
4. A least square line was calculated and plotted and "a",
which is the sludge synthesis coefficient, equals 0.30
and "b", which is the endogenous respiration coefficient, equals
0.01 (Day" ) were obtained.
The values for "a" and "b" are reasonable according to ranges of
0.3 to 1.0 for "a" and 0.014 to 0.35 for "b" reported for various
industrial wastes by McCartyGS] and Eckenfelder.^ ' Values for
"a" and "b" may be only approximate when obtained in this way because
all influent VSS may not be biodegradeable.
The values for "a" and "b" were then used to obtain coefficients
a' and b' for the theoretical oxygen requirements of the biological
solids in the aeratiosutank. This was done by using relationships
given by Eckenfelder:^ '
"a" + a' = 1 (7)
b'=1.5»b"
where
"a" and "b" are as defined earlier.
a1 = unit weight of oxygen required per unit weight of COD
removed.
b1 = unit weight of oxygen required per unit weight of VSS
destroyed by endogenous respiration.
1.5 = oxygen equivalent of MLVSS
From equations (7) and (8), a1 = 0.70 and b' = 0.015. These values
were then used for calculation of total theoretical oxygen requirement
using equation (9)r '
V a'VLe> +b'Sa (9>
In addition, an approximate method was used to account for oxygen
requirement for nitrification. In this method, the percentage
of oxygen required for nitrification was estimated by making an
ultimate BOD analysis and nitrification analysis on a sample of
influent wastewater. The results of the analyses indicated that
about 28 percent of the oxygen required in 20 days was utilized
by nitrifying organisms.
42
-------
o:
Ld
Q.
CO
CO
OD
CO
OD
_l
I
Q
LU
O
O
O
a:
a.
CO
CO
0.100
0.080
0.060
0.040
0.020
-0.020
Y= 0.30 X-0.01
V - 0.67
a = 0.30
/ b = 0.01
I
0 0.10 0.20 0.30 0.40
COD REMOVED -LBS/LB MLVSS PER DAY
FIGURE 8. MEA SYNTHESIS AND ENDOGENOUS RESPIRATION COEFFICIENTS - 1970
43
-------
The average theoretical oxygen requirement that resulted was 29.4
pounds per day compared to 26.4 pounds per day for the measured
oxygen requirement as determined by oxygen uptake measurements.
These values were based on the entire aeration tank mixed liquor
volume, an average MLVSS concentration of 1,750 mg/1, and an average
loading rate of 0.05 pound of COD per pound of MLVSS.
The data that were used for calculation of the average theoretical
oxygen requirements were taken over the time interval 10-23-70 to
11-20-70. The same interval was used for measured oxygen uptake
so the two values could be compared. In addition, there were no
reliable oxygen uptake data earlier in the season.
The difference between theoretical and measured oxygen requirement
values may be primarily due to variation of the food to microorganism
ratio in the aeration tank (0.03 to 0.10) whicjumay cause wide
variation in the measured oxygen uptake rate. '
Data for aerator evaluation were not obtained during this study, however,
calculations were made bousing practical values for <* and 0 in the
following equation:^ ' ^ '
C -C
N = NA x S|j L x 9T~20 x <* (10)
0 L20
where
N = # oxygen transferred per hp-hr in field operation
NQ = # oxygen transferred per hp-hr in water at 20°C and zero DO
= 2.0 from a previous study using the same aerator and aeration tank
and the same liquid volume.
GSW = DO saturation at aeration tank temp, (mg/1)
C. = DO in aeration tank at aeration tank temp, (mg/1)
C20 = DO of tap water at 20°C = 9.17 (mg/1)
6 = temp, correction coefficient (assumed at 1.02)
T = temp, in °C of aeration tank mixed liquor
« = relative oxygen transfer factor (assumed 0.85)
44
-------
Since no data were obtained on dissolved oxygen concentration at
saturation at various temperatures, C~u was assumed to equal the
DO concentration of tap water, i.e., c" = C?n at 20°C. This assumption
was in keeping with the others in this^analysts which was intended
to show only relative magnitude of oxygen parameters, theoretical,
measured, and added.
Data used for the calculations were taken from the same period
of operation as the data used for measured and theoretical oxygen
requirement values. The average was 24 Ibs oxygen per day for
the 1 horsepower aerator used in this study. This value compares
favorably with the average theoretical oxygen requirement of 29.4
Ibs oxygen per day if consideration is given to additional oxygen
tranferred at the air-water interface. Through this process, a
check has also been indirectly applied on the magnitude of "a",
"b", a1, and b1.
Nitrogen and phosphorus data for 1969 and 1970 were not extensive
enough for use in making accurate nitrogen and phosphorus balances.
Table 2 did not contain sufficient data to indicate nitrification
in 1969, but data in Table 5 indicated there was nitrification
during 1970. The MEA and RBC Comparison section covers nutrient
relationships further.
RBC
A major problem in the kinetic evaluation of the RBC was the inability
to determine the amount of active biological mass in the system.
The thickness of the slime on the discs was quite variable on any
given disc and from the first disc to the last disc in the direction
of flow. There was also continuous sloughing of slime which complicated
the problem, and there was no assurance that slime on the inner
part of the discs was similar to that on the visible'portion of
the discs.
An attempt was made to evaluate the RBC by using disc surface area
instead of bioraass to develop a relationship between removal rate
and effluent soluble COD concentration similar to that presented
in Figure 6 for the MEA, but no meaningful relationship was apparent.
A comparision of influent total COD and COD removed per 1000 square
feet of disc surface was attempted, and the relationship shown
in Figure 9 resulted. COD removed was calculated by subtracting
effluent soluble COD from influent total COD. The removal rate
uniformity over the 10-17°C temperature range indicated 9 was close
to 1.0 under the conditions of operation. Even though the temperature
varied over a range of 10-17°C, it was also shown in Figure 9 as
average temperature because the temperatures of the two disc stages
45
-------
12
o:
LJ
a.
h- 10
T
T
T
AVE. TEMP: io.o-i7.o°c
DATE : 9-15-11-17-70
o
o
o
8
CD
I
Q
Ld
O
2
LU
o:
o
o
o
i
\
\
Y =96X-0.3
"r"=0.99
\
\
\
24 6 8 10 12 14
COD APPLIED - LBS /1000 SO FT PER DAY
16
FIGURE 9. RBC REMOVAL CHARACTERISTICS
-------
were averaged. Detention time during the data gathering period
varied from 4.1 to 10.0 hours, and influent total COD concentration
varied from 975 to 3,000 mg/1. Variation of active biomass was
unknown.
Even in view of a variation of 7°C in temperature, a 300 percent
change in influent total COD concentration, and a 250 percent change
in detention time, the removal rate appeared to be dependent only
upon the amount of COD applied. This relationship holds at least
to 10.5 pounds of total COD per 1,000 square'feet of disc surface,
which was the highest loading rate used.
COMPARISON OF MEA AND RBC
One objective of this study was to compare these two methods of
cannery wastewater treatment. During the study, certain characteristics
of the two units were revealed which are best covered in this section
of the report.
Detention Time vs COD Removal
Minimum theoretical hydraulic detention time attained on both units
was dependent upon the DO limitations mentioned earlier in the
report. As a result, the minimum THDT for the MEA was 8.7 days
based on an average flow of 2.6 gpm. Minimum for the RBC was 4.1
hours at an average flow of 2.4 gpm. Calculation of detention
time for the RBC in Figure 10 is total detention time as discussed
earli er.
Figure 10 is presented to show variation of total COD removed in
relation to detention time. The amount of COD removed per day
shows an inverse relationship with detention time in the MEA. This
same trend is less pronounced in the RBC. Th.e roost significant
fact evident in the figure is the much larger detention time necessary
in the MEA to achieve the same COD removal rate as the RBC. Total
COD removed in Figure 10 was calculated in the same manner for
both units, effluent total COD was substracted from influent total
COD.
COD Removal per Horsepower - day
COD loadings to both units were in the same range throughout the
study, and removals were also comparable although a much longer
detention time was required by the MEA, as mentioned previously.
Figure 11 relates the COD applied to the power required to remove
the COD. Since both units removed similar amounts of COD at similar
loadings, the two least square lines shown actually approximate
47
-------
20.0
10.0
MEA
c/)
s
Q
I
LU
5.0
DATE 19-15 -10-27-70
Ld
h-
LU
Q
1.0
0.5
O.I
RBC
1
10 20 30 40 50
TOTAL GOD REMOVED-LBS/DAY
60
FIGURE 10. RBC AND MEA DETENTION TIME VS COD REMOVAL
48
-------
Q 100
1
Q.
X
v 75
O
LU
§ 50
LU
o:
o
O 25
o
POUNDS
o
l l 1 l I
RBC >/
*X
^r^
y
s /-
S ij^* MEA
/S-^
*\ III!
20 40 6(
POUNDS COD APPLIED/DAY
FIGURE 11. MEA AND RBC COD ADDED VS COD REMOVED/HP-DAY
49
-------
the 2:1 horsepower requirement ratio for the two units, i.e., 1
horsepower aerator for the MEA and about 1/2 horsepower total requirement
for the RBC disc drive and sludge scraper motors.
Figure 11 presents actual field data, but it does not present an
entirely accurate picture of power requirements for the following
reasons:
1. Data from Autotrol Corporation indicates the 1/2 horsepower
disc drive motor does not operate at capacity until the discs are
rotated in excess of 6 rpm. Rotation during the study was about
4 rpm and Autotrol data indicate this speed can be maintained with
a power input of 0.1 horsepower.
2. The 1-horsepower aerator in the MEA delivers 2 pounds
of oxygen per hour at standard conditions. Aerators above 5 horsepower
capacity will deliver between 3 and 4 pounds of oxygen per horsepower-
hour under standard conditions.
In view of the above reasons, both units would probably remove
considerably larger amounts of COD per horsepower-day in full-
scale treatment plants.
Sludge Production
In an ideal situation, none of the sludge synthesized would be
intentionally discharged from the MEA during the canning season,
and most of the excess would then be digested by endogenous respiration
at the end of the season. However, in actual operation, some loss
of suspended matter will usually occur in the effluent. This was
the case with the MEA during the 1970 season. Most of the sludge
was nevertheless held in the tank until an upset period during
the weekend of November 7 and 8, the details of which are covered
in the Organic Overloads Section. This was evidenced by constantly
increasing mixed liquor suspended solids and relatively constant
effluent suspended solids concentration of less than 100 mg/1.
The MEA did operate from August through October as an efficient
COD removal system without producing an immediate sludge disposal
problem.
In contrast, the RBC continually produced sludge, which on a larger
scale operation would have to be given further treatment and disposal.
The quantity and other characteristics of the RBC sludge were not
determined in this study. Some volumetric settleable solids analyses
were run on the sludge, and they indicated the sludge settled readily.
The amount of settleable solids data is limited, and therefore,
may not be representative of the highly dynamic sludge sloughing
and synthesis.
50
-------
Effluent Suspended Solids
Both units had secondary clarifiers with adequate settling capacity
to handle the flows encountered. The tube settler module in the
MEA had an overflow rate of 230 gpd/sq ft at 2 gpm of flow, and
the RBC final clarifier had an overflow rate of 190 gpd/sq ft at
2 gpm.
Table 11 give average effluent suspended and volatile suspended
solids values for the two units during their operation. The level
of suspended matter in the MEA effluent was fairly steady throughout
the period from September 15 to November 6. The overall average
suspended solids concentration was 72 mg/1. Then on November 7
an upset occurred and large amounts of solids passed through the
tube settler for the remaining two weeks of the season.
The level of suspended matter in the RBC effluent was more dynamic,
as indicated by the larger standard deviation, and an overall average
suspended solids of 56 mg/1 was observed.
On a few occasions, both effluents were quite clear with only very
small diameter particulate matter visible, but generally, they
did not exhibit the clarity associated with a well designed and
operated activated sludge plant. The effluents from both units
would not meet many present or probably future water quality and
effluent standards on suspended solids concentration for discharge
to receiving waters, but they would undoubtedly be acceptable for
discharge into a municipal sewage system.
Temperature Effects
Figures 7 and 9 indicate both units are not significantly sensitive
to temperature change within the relatively small range in which
they were operated. No meaningful data were gathered in the 0-
10°C range, but substrate removal rates would probably be lower
in-this range.
Sub-freezing temperatures would hamper the operation of the RBC
to the point that it would probably have to be insulated unless
the source of wastewater was steady and warm enough to prevent
freezing. Even if the liquid in the RBC tank would not freeze,
the slime may be unable to metabolize substrate efficiently due
to the magnitude of temperature change with each disc rotation,
i.e., sub-freezing air temperature above the liquid level and above-
freezing liquid temperature.
51
-------
Table 11
RBC AND MEA EFFLUENT SOLIDS CONCENTRATIONS
en
ro
Susp. Solids
Vol. Susp. Solids
Period
(1970)
9/15-9/30
10/1-10/16
10/17-11/7
11/8-11/21
X
38
93
36
56
RBC
s
31
46
16
45
n
5
5
5
4
X
70
72
75
325
MEA
s
16
19
13
143
n
5
5
3
4
X
36
65
38
92
RBC
s n
28 5
30 5
2
1
X
65
63
70
260
MEA
s
16
15
9
104
n
5
4
3
4
x = mean (mg/1)
s = standard dev. (mg/1)
n = No. of analyses
-------
Organic Overloads
A short term organic shock loading would be expected to cause reduction
in substrate removal efficiency of the RBC to a greater degree
than in the MEA because of the shorter detention time in the RBC.
No short term overloads were detected in the analytical results
so unit response to such overloads was not determined.
On the weekend of November 7-8 there was apparently a relatively
long term organic overload applied to both units. No analyses
were taken during the weekend, but on Monday morning the following
was observed:
1. Effluents from both units were very turbid and the DO
was lower than the previous week.
2. The RBC had a very strong unpleasant odor.
3. There was foam on the aeration tank that had never been
observed before.
4. A representative from the cannery said there was very
little wash down water used over the weekend, and only squash was
processed continuously for both days which probably resulted in
a wastewater of high organic content.
On Tuesday, November 10, conditions in the units were as shown
in Table 12. There was no odor observed from the MEA, and there
never had been in the past. Odor from the RBC was only slight,
which could be called normal because the RBC generally exhibited
a slightly unpleasant odor at least during squash processing. In
general, the routine samples and observations taken on November
10, showed that the RBC was functioning as well as ever. The MEA
continued to discharge solids, and the substrate removal efficiency
decreased for the rest of the season. Mixed liquor suspended solids
concentration in the MEA decreased from 2310 mg/1 on Nov. 6 to
1210 on November 24, while the sludge volume index went from 80
to 103, despite the fact the unit was receiving wastewater, and
all other environmenal conditions were kept at proper levels.
i
Nitrogen and Phosphorus
Comparison of the MEA and RBC on nitrogen and phosphorus removal
efficiency and requirements for treatment was not made due to the
limited number of samples taken and lack of control of some of
the variables involved.
53
-------
Table 12
ORGANIC OVERLOAD RECOVERY OBSERVATIONS - NOV. 10, 1970
Parameter
MEA
RBC
DO
Odor
Effluent Appearance
Effluent S.S.
% COD Removal
back to normal
non
very turbid
up 200% of average
73
back to normal
slight
slightly turbid
less than usual
(about 30 mg/1)
92
54
-------
The ratio of total influent BOD to total nitrogen added to total phosphorus
added during the 1970 season was 100:15:2.2 which does not include
any nitrogen or phosphorus present in the influent wastewater before
nutrient addition. This ratio was not calculated for the RBC because
the influent wastewater and nutrient addition were the same as
for the MEA.
Constant nutrient addition, and the fact that influent BOD never
exceeded the assumed maximum of 2,000 rng/1 upon which nutrient
addition rate was based, support the assumption that there were no
nutrient deficient periods during the 1970 season.
Nitrification in the MEA in 1969 was not demonstrated by the results.
There was insufficient data in 1969 to demonstrate nitrification in the
MEA. In 1970 there was adequate data to show evidence of nitrification
in the MEA. There was no evidence of nitrification in the RBC which
seems reasonable because the maximum hydraulic detention time was only
10 hours. However, the biomass detention time on the discs is probably
much longer, and nitrification could occur even at relatively low hydraulic
detention times if all other conditions for nitrification were met.
For both units nutrient addition was made on the basis of an assumed
maximum BOD of 2,000 mg/1 and a BOD:N:P ratio of 100:5:1. For the
purpose of this study, this was an adequate approach, but on full scale
treatment plants it would be necessary to keep nutrient addition at
the minimum rate consistent with maximum cell synthesis and endogenous
respiration so nutrient cost would be minimized and excess effluent
nutrients would not add to problems associated with eutrophication
of receiving waters.
Effluent Comparison
Table 13 compares the effluents from the MEA and RBC for the 1970 season.
Values shown are for the same time period, September 15, through November
20, and for very closely the same influent wastewater flow volume,
characteristics, and nutrient feed rates.
The effluents have characteristics similar to domestic wastes so there
would probably be no surcharge cost applied if these effluents were
discharged to municipal sewers unless such a surcharge was based on
flow volume only. Surcharge is intended to mean an additional assessment
for wastewater quantitynor quality that is above what is considered
normal for a cannery. ' Also, consideration should be given to the
fact that the remaining COD is probably less biologically degradeable
because the more readily metabolizable portion of the COD has been
removed.
55
-------
Table 13
COMPARISON OF EFFLUENTS - 1970
MEA
RBC
Total*
BOD
Total*
COD
Total
BOD /COD
Soluble
BOD
*
Soluble
COD
Soluble
BOD /COD
% Soluble
BOD
% Soluble
COD
BOD:N
BOD:P
Average
112
207
0. 54
57
113
0. 50
51
55
5.1:1
3.1:1
Range
57-198
80-708
0.38-0.95
23-110
36-324
0.33-1.34
34-77
45-86
7. 6:1-2.4:1
5.8:1-1. 9:1
Average
148
180
0. 82
110
128
0.86
74
71
1. 1:1
6.1:1
Range
65-239
59-420
0.42-0. 90
43-200
46-291
0.40-0. 86
51-86
45-100
6. 1:1-0. 1:
23.8:1-0.5
I*
'"Concentrations in mg/1
56
-------
SECTION VII
ACKNOWLEDGMENTS
The personnel of United Flav-R-Pac Growers, Inc. are thanked for providing
a study site and cooperation. Also, Autotrol Corporation employees are
thanked for providing the RBC.
Gratitude is extended to the Oregon State University, Department of Civil
Engineering and Pacific Northwest Water Laboratory staff for their technical
and administrative roles in this study.
57
-------
SECTION VIII
REFERENCES
1. Federal Guidelines for Equitable Recovery of Industrial Waste
Treatment Costs in Municipal Systems, Oct., 1971. U. S. Environmental
Protection Agency, Office of Water Programs, Washington, D. C.
2. Standard Methods for Examination of Water and Wastewater, 12th Edition,
1965, Boyd Printing Co., Inc., Albany, New York.
3. FWPCA Methods for Chemical Analysis of Water and Wastes. Nov., 1969,
U.S. Dept. of the Interior. Fed. Water Pollution Control Ad., Div. of
Water Quality Research, Analytical Quality Control Lab., Cincinnati, Ohio.
4. Monod, J., Recherches sur la croissance des cultures bacteriennes,
Herman and Cie, Paris, 1942.
5. McCarty, P.L., "Biological Treatment of Food Processing Wastes,"
Proceedings of the First National Symposium on Food Processing Wastes,
U. S. Dept. of the Interior, Fed. Water Quality Ad., Portland, Ore.,
April, 1970, p.p. 327-346.
6. Eckenfelder, W. W., and O'Connor, D. J., Biological Waste Treatment,
Pergamon Press, New York, 1961.
7. Eckenfelder, W. W., "Comparative Biological Waste Treatment Design,"
Jour, of the Sanitary Engr. Div.. ASCE, Vol. 93, No. SA6, Dec., 1967, p.p.
157-170.
8. Eckenfelder, W. W., Industrial Water Pollution Control, McGraw-Hill
Book Co., New York, 1966.
9. Conway, R. A., and Kumke, G. W., "Field Techniques for Evaluating
Aerators," Jour, of the Sanitary Engr. Div., ASCE, Vol. 92, No. SA2, Apr.,
1966, p.p. 21-42.
10. Maystre, Yves, and Geyer, J. C., "Charges for Treating Industrial
Wastewater in Municipal Plants," Jour. Water Poll. Control Fed., Vol. 42,
July, 1970, p.p. 1277-1291. ,
59
-------
BOD
BODS
COD
CODS
SS
vss
MLSS
MLVSS
TKN
Ammonia-N
Nitrate-N
Nitrite-N
Total-P
Ortho-P
ALK
DO
D.T. or THDT
Cu ft
Sq ft
Ib or #
"r"
hp
SECTION IX
GLOSSARY
5-day, 20°C biochemical oxygen demand, mg/1
Soluble BOD, mg/1 (0.45 y filtrate)
Chemical oxygen demand = COD (Total) = CODT, mg/1
Soluble COD, mg/1 (0.45 M filtrate)
Suspended solids, mg/1
Volatile suspended solids, mg/1
Mixed liquor volatile suspended solids, mg/1
Mixed liquor volatile suspended solids, mg/1
Total Kjeldahl nitrogen, mg/1 as nitrogen
Ammonia nitrogen, mg/1 as nitrogen
Nitrate nitrogen, mg/1 as nitrogen
Nitrite nitrogen, mg/1 as nitrogen
Total phosphorus, mg/1 as phosphorus
Orthophosphates, mg/1 as phosphorus
Total alkalinity, mg/1 as calcium, carbonate
Dissolved oxygen, mg/1
Theoretical hydraulic detention time, calculated from
flow and volume data (Minutes, Hours, or Days)
Cubic feet i
Square feet
PoundCs)
Correlation Coefficient
Horsepower
61
-------
gpd/sq ft Gallons per day per square foot
rpm Revolutions per minute
rph Revolutions per hour
gpm Gallons per minute
mgd Million gallons per day
mg/1 Milligrams per liter
ft U. S. GOVERNMENT PRINTING OFFICE : 1973514-154/268
62
-------
SELECTED WATER
RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
1. Report No.
2.
3. Accession No.
w
4. Title
Cannery Wastewater Treatment with Rotating Biological
Contactor and Extended Aeration
7. Author(s)
Mr. Max W. Cochrane, Mr. Robert J. Burm, and Mr. Kenneth
fl
9. Organization
National Waste Treatment Research Program
Pacific Northwest Environ mental Research Laboratory
Environmental Protection Agency
Corvalli.s, J)R
12. Sponsoring Organization
Pacific NW Environmental Research Laboratory, EPA
1$. Supplementary Notes
Environmental Protection Agency report
number, EPA-R2-73-021J-, April 1973.
5. Report Date
6.
8. Performing Organization
Report No.
10. Project No.
11. Contract/Grant No.
13. Type of Report and
Period Covered
1969-1970
16. Abstract
Fruit and vegetable cannery wastewater was treated during two canning seasons by
two pilot plants of the rotating biological contactor and extended aeration types.
The objective was to determine the effectiveness of these biological treatments
processes on cannery wastewater and to compare the two units under the same operating
conditions.
Nitrogen and phosphorus were added to the influent wastewater so the BOD:N:P
ratio was kept above 100:5:1.
Both treatment units attained organic removals of over 90%. However, much less
detention time was necessary in the RBC to obtain removals comparable to the extended
aeration plant. Sludge produced by the RBC required additional treatment, but most
of the sludge produced in the extended aeration plant was aerobically digested in the
aeration tank.
Effluent quality from both units was about the same over the operating temperature
range of 10-20°C, although the RBC appeared to recover more rapidly from organic shock
loading. Neither unit produced an effluent that could be discharged to surface waters
without further treatment.
17a. Descriptors
*Waste Water Treatment, *Water Pollution Control,
Canneries, Biological Treatment, Aerobic Treatment
17b. Identifiers
Extended Aeration, Rotating Biological Contactor
industrial Wastes,
17c. COWRR Field & Group
18. Availability
Max W. Cochrane
19. Security Class.
(Report)
20. Security Class.
(Page)
21. No. of
Pages
22. Price
Send To:
WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON. D. C 20240
Abstractor
Institution
WRSICI02(REV JUNE 1971)
SPO
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