WATER POLLUTION CONTROL RESEARCH SERIES
12060—03/68
Aerated Lagoon Treatment of
Food Processing Wastes
ENVIRONMENTAL, PROTECTION AGENCY • WATER QUALITY OFFICE
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WATER POLLUTION CONTROL RESEARCH SERIES
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AERATED LAGOON TREATMENT OF
FOOD PROCESSING WASTES
Prepared by
Kenneth A. Dostal
Pacific Northwest Water Laboratory
200 Southwest 35th Street
Corvallis, Oregon 97330
for the
WATER QUALITY OFFICE
ENVIRONMENTAL PROTECTION AGENCY
Project #12060 03/68
March 1968
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C., 20402 - Price 55 cents
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TABLE OF CONTENTS
Chapter Page
INTRODUCTION 1
Problem 1
Purpose 2
Authority 2
SUMMARY 3
THE KELLEY-FARQUHAR & COMPANY PLANT AND WASTE
TREATMENT FACILITIES 5
Processing Plant 5
Waste Treatment Plant 6
Description 6
Operation 7
STUDY OF TREATMENT OPERATIONS 9
Data Collection Methods 9
Study Results 10
EVALUATION OF TREATMENT OPERATIONS 17
BIBLIOGRAPHY 27
APPENDIX 29
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iii
LIST OF FIGURES
Figure
1 Industrial Waste Treatment Facilities,
Ferndale, Washington
2 Variation in Water Use With Time ..... 32
3 Quiescent Sedimentation Tests ...... 33
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IV
LIST OF TABLES
Table Page
1 Foods Processed and Water Used 34
2 Temperature and pH Data, July 13, 1967 35
3 Temperature and pH Data, July 20, 1967 36
4 Temperature and pH Data, July 27, 1967 37
5 Temperature and pH Data, August 3, 1967 .... 38
6 Temperature and pH Data, August 10, 1967 .... 40
7 Temperature and pH Data, August 17, 1967 .... 41
8 Lagoon Temperature Data 42
9 Lagoon Dissolved Oxygen Data 43
10 Solids Data 45
11 Inorganic Nutrient Data 46
12 Organic Carbon, pH and Alkalinity Data 47
13 BOD and COD Data 48
14 Average Percent Reductions 49
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ABBREVIATIONS
BOD 5-day, 20°C biochemical oxygen demand, mg/1
COD chemical oxygen demand, mg/1
SS suspended solids, mg/1
TS total solids, mg/1
VSS volatile suspended solids, mg/1
TVS total volatile solids, mg/1
Temp. temperature, °C
NH3-N ammonia nitrogen, mg/1 as N
T.K.-N total Kjeldahl nitrogen, mg/1 as N
T. P04 total phosphate, mg/1 as P04
0. PO^ ortho phosphate, mg/1 as P04
Alk. total alkalinity, mg/1 as CaC03
TOC total organic carbon, mg/1
DOC dissolved organic carbon, mg/1
D.O. dissolved oxygen, mg/1
SVI sludge volume index
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vl
ACKNOWLEDGMENTS
The assistance and cooperation of Kelley-Farquhar & Co.
and the State of Washington Water Pollution Control Commission
are appreciated.
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INTRODUCTION
Problem
The food-processing industry is the second largest industrial
source of waterborne organic wastes in the Pacific Northwest.
Wastes from the processing of foods are usually large in volume
and of high oxygen-consuming pollutional strength. Adequate
secondary treatment of these wastes by conventional processes
is complicated by the seasonal nature of most of the food-
processing plants and the large capital expenditures for waste
treatment facilities which may be used for only a few months
each year.
Recently, several other industries have constructed waste
treatment plants consisting of small, deep ponds with oxygen
supplemented by mechanical surface aerators. Process efficiency
can be varied over a wide range by control of nutrient feeds,
oxygen addition, aeration basin detention time, and solids
recycle. The pulp and paper industry estimates construction and
operational costs of aerated lagoons at 60 and 40 percent, respec-
tively, of those for activated sludge treatment in the 90 percent
BOD removal range. Land requirements are reported to be
about 5 to 10 percent of that used by conventional stabilization
basins loaded at 50 pounds of BOD per acre per day.
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Although two food-processing plants, both in the State of
Washington, have recently installed aerated lagoon facilities,
there is a scarcity of good, reliable operational data. There
is a very distinct need for this information so that the design
of new facilities can be adequately assessed by State regulatory
agencies prior to construction.
Purpose
The purpose of this study was to gather good operational
data on a full-scale aerated lagoon which is used to treat food-
processing wastes.
Authority
Following discussions between personnel of the Federal Water
Pollution Control Administration (FWPCA) and representatives of
the various State regulatory agencies concerned with water pol-
lution in the Pacific Northwest, a study was initiated on treat-
ment of food-processing wastes by aerated lagoons. This study
was of specific interest to the State of Washington Water Pollution
Control Commission as evidenced by the letter shown in the Appen-
dix, page A-l. The Commission said, "...we have a very distinct
need for additional performance and design information."
Federal authorization for this type of study comes from the
Federal Water Pollution Control Act, as amended.
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SUMMARY
This report presents the data collected and the conclusions
drawn from a six-week period of sampling of an aerated lagoon
used to treat wastes from the frozen pea processing plant of
Kelley-Farquhar located at Ferndale, Washington.
Eleven hour composite samples were collected one day per
week from July 6 to August 17, 1967, of the influent to the 5.6
million gallon aerated lagoon, effluent from the lagoon and
effluent from a 135,000 gallon polishing pond.
Conclusions drawn from the sampling program include:
1. Water use per 1,000 pounds of peas processed averaged
3,500 gallons. Suspended solids, BOD and COD contributions to
the waste stream per 1,000 pounds of peas averaged 10, 24, and
41 pounds, respectively.
2. Reductions in total BOD and COD across the aerated
lagoon averaged 76 and 59 percent, respectively. Dissolved BOD
was reduced by 95 percent and dissolved COD by 82 percent.
3. Inorganic nutrients were not reduced appreciably by the
aerated lagoon.
4. The polishing pond readily filled with solids and ceased
to function as a removal device. Suspended solids increased from
340 to 580 mg/1 across the aerated lagoon and the average reduction
by the polishing pond was 10 percent.
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5. Current operation of the aerated lagoon results in
foaming problems during the first week or two of operation and
the growth of filamentous floe which causes a highly bulked
sludge (SVI>1000).
6. When all four aerators are in operation, the reduction
in organics across the complete-mixed lagoon can be predicted
using available formulations. Necessary constants were obtained
from this study.
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THE KELLEY-FARQUHAR & COMPANY PLANT
AND WASTE TREATMENT FACILITIES
Processing Plant
Kelley-Farquhar & Company owns and operates several food
processing plants in western Washington and the Pacific North-
west. Their plant at Ferndale, Washington, processes peas,
carrots, asparagus, broccoli, strawberries, and raspberries.
All of the finished products are frozen. The plant normally
processes vegetables and berries which are grown on about
6,000 acres in Whatcom and Skagit Counties and disburses
nearly $2,000,000 annually in payroll and payments to farmers
and others.
By far the strongest wastes are those derived from the
processing of peas for freezing. In 1967 pea processing
started July 6 and continued until August 17. For about the
first week, processing was only done during the day shift.
Then as the quantity of peas available for processing increased
markedly, two shifts per day, six days per week, and one shift
on Sunday were utilized for processing. Normally the day shift
started at 8:00 a.m. and continued to about 5:30 p.m. Following
clean-up the evening shift started at 7:00 p.m. and ran until
4:30 a.m. the following morning.
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Waste Treatment Plant
Description
Wastes flow by gravity from the processing plant to a
sump from which they are pumped to a rotary screen. Liquid
effluent from the screen flows by gravity to the aerated
lagoon. Screened solids are loaded on trucks and hauled away
for use as a food supplement for cattle. Domestic wastes are
kept separate from the processing wastes and are added to the
city's sewers.
Effluent from the aerated lagoon flows through a polishing
pond and then to the Nooksack River. The outfall is located
about six miles upstream from the mouth of the river which dis-
charges into Bellingham Bay.
The aerated lagoon has a surface area of 1.75 acres, an
average depth of ten feet and a volume of 5.6 million gallons
(mg). Side slopes of the lagoon are two horizontal to one
vertical. Four 50 horsepower (hp) aerators, mounted on fixed
platforms in the lagoon, have a rated aeration capacity of
12,000 pounds of oxygen per day. Effluent from the aerated
lagoon flows into the north end of the polishing pond as shown
on Figure 1 (Appendix, page A-2). Effluent from the 135,000-
gallon pond overflows at the south end. The original design
called for recirculation of settled solids from the polishing
pond back to the aerated lagoon but this practice was never
initiated.
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Operation
The aerators are only used during the pea processing period
since the quantity and strength of wastes from the other processed
foods are considerably lower. For the first week or two of pea
processing, less than four aerators are usually kept in operation
depending upon the quantity of peas processed and the dissolved
oxygen (D.O.) levels in the aerated lagoon. D.O. levels in the
aerated lagoon are routinely checked twice a day by plant personnel.
After the initial period of intermittent aerator operation, all
four are run continuously until pea processing is terminated.
Then the aerators are operated intermittently again for about
another week to assure stabilization of the organic material present
in the aerated lagoon.
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STUDY OF TREATMENT OPERATIONS
Data Collection Methods
On July 13, 1967, and each Thursday thereafter for the
period of study, a set of composite samples was taken of the
aerated lagoon influent, lagoon effluent, and polishing pond
effluent. Each set of samples was composited across the day
shift, including clean-up, from 8:00 a.m. to 7:00 p.m. The
samples were collected hourly on July 13 and composited accord-
ing to flow. On July 20 and following Thursdays all samples
were composited with time. The primary reason for the change
in method of compositing is shown on Figure 2. Hourly varia-
tions in water use were less than 10 percent from the average
for July 13. All but one of the 30-minute periods of water
use during a previous trip to the plant, August 17, 1966, showed
deviations from the average use of less than ten percent.
All samples were kept on ice during collection and were
transported to the Laboratory in Corvallis on ice immediately
after collection. Analyses were started on the morning follow-
ing the day of collection. All analyses were performed accord-
ing to Standard Methods^) with the following exceptions:
nitrate nitrogen, (-*) Kjeldahl nitrogen,' ' total and ortho
phosphate,^ ' and total organic carbon and dissolved organic
carbon. ' In addition to the regular BOD and COD analyses sane
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of the samples were centrifuged and these two analyses were
repeated on the centrates. The samples were centrifuged at
about 3,000 revolutions per minute for fifteen minutes.
Grab samples were also taken from the aerated lagoon and
the polishing pond effluents for onsite pH and temperature
measurements and for quiescent sedimentation tests. Grab
samples of the aerated lagoon and polishing pond effluents
were also taken and returned to Corvallis for examination of
the numbers and kinds of biological organisms. Some dissolved
oxygen readings were taken with a D.O. probe at various depths
and locations in the aerated lagoon. The probe was calibrated
by Winkler^- ' D.O. measurements onsite prior to use in the
lagoon. The sampling stations shown in Figure 1 were about
midway between the aerators and the bank. Previous sampling' '
had shown that the lagoon was completely mixed when all four
aerators were used and these sampling locations would give
representative D.O. concentrations.
Study Results
The quantities of peas and raspberries processed, the
amount of water used and the number of aerators in operation
for each of the days that samples were taken are shown in Table 1.
From 96,000 to 180,000 pounds of peas were processed during the
8:00 a.m. to 5:30 p.m. shift. The quantity of raspberries
processed varied from 0 to 21,000 pounds during the day shift.
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Water use was relatively constant and independent of quantity
of food processed, varying from 456,000 to 563,000 gallons
during the 8:00 a.m. to 7:00 p.m. period. On July 13, only
three of the four aerators were in operation, the southeast one
was off, and the following week, two were in operation, both
the southeast and northwest ones were turned off. All four
aerators were placed in operation on July 26 and continued in
operation until after the end of pea processing.
The pH and temperature data collected onsite in the grab
samples of the lagoon influent, lagoon effluent, and polishing
pond effluent are shown in Tables 2 through 7 in the Appendix.
.Overall, the temperature range in the lagoon influent was from
17°C to 29.5° with a pH range from 6.7 to 8.2. The lagoon
effluent had a temperature range of 19.5 to 23°C and a pH range
of 6.6 to 8.1. Temperature and pH readings on the effluent
from the polishing pond were nearly identical to those of the
effluent from the aerated lagoon. For the six days of sampling
the temperature drop across the lagoon averaged 0°C with daily
averages ranging from a drop of 2°C to a temperature increase
of 2°C. The air temperature was not followed as closely, but
it generally ranged from 18 to 23°C. The aerated lagoon acted
as a buffer zone, evening out the pH and temperature fluctuations
that occurred in the influent stream.
Table 8 presents temperature measurements that were taken
in the aerated lagoon at the sampling points shown on Figure 1.
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Even though less than four aerators were in operation on July
13 and 20, the temperature data indicate fairly good mixing at
least in the upper layer of the lagoon. On August 3 there
appeared to be good mixing throughout the lagoon, evidenced by
the temperatures taken at 11:00 a.m. and 3:00 p.m.
Dissolved oxygen data collected with the probe are shown
in Table 9. On July 13, the dissolved oxygen content near the
southeast aerator, the one not running, was 0.3 to 2.1 mg/1
lower than at the other three sampling points. There was a
range in oxygen content from 0.6 to 1.2 mg/1 in the morning
and from 1.0 to 2.4 mg/1 in the afternoon at the other three
stations both of which were probably due to the southeast
aerator. Both the southeast and the northwest aerators were
off on July 20. Near the surface the oxygen content was lower
near these two aerators (stations 1 and 3) than it was at sta-
tions 2 and 4. At the five foot depth, the oxygen content was
low, about 0.2 mg/1, and rather uniform at all four stations.
With all four aerators running on July 27 and August 3,
the oxygen content ranged from 1.6 to 5.9 mg/1 in the lagoon.
Although the values at the 8-foot depth were less than at the
1-foot depth, there was excess oxygen available at all of the
sampling points. The D.O. content of the effluent from the
polishing pond was about 4 mg/1 lower than the contents of the
aerated lagoon during the afternoon of August 3. This resulted
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from the gas released upon anaerobic decomposition of the
sludge which had accumulated in and filled the polishing pond.
Samples of the lagoon and pond effluents collected on August
3 and analyzed by the Winkler method showed an oxygen content
of about 1.5 mg/1. The oxygen demand in the lagoon had in-
creased over that of the previous week, but the D.O. was still
in a range that would not inhibit biological activity. D.O.
concentrations on August 17 were down to 0.6 mg/1 and showed
good mixing of the lagoon contents, both near the surface and
at a depth of 8 feet. The measured concentration was near the
level which may start to cause a slowdown in biological break-
down of the organics.
Quiescent settling tests were run in 2-liter graduated
cylinders on grab samples of the lagoon effluent taken on the
last four sampling trips. Figure 2 presents a plot of sludge
volume in percent versus settling time in minutes for three of
these tests. The results from the settling test conducted on
August 3 were very similar to those obtained on August 17 and,
therefore, are not shown. These tests were also conducted on
the effluent from the polishing pond, but in every case they
were virtually identical to those on the aerated lagoon effluent.
On the first two sampling trips, these tests were not conducted
since it was impossible to discern an interface upon settling.
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For the July 27 sedimentation curve the sludge volume index
(SVI) was about 120, indicative of a good settling sludge. On
the other three days, August 3, 10, and 17, the SVI was in excess
of 1,000 which indicates that solids removal by conventional
clarification methods would be almost impossible. A possible
explanation for the bulking sludge will be discussed later.
Table 10 presents the results of the solids analyses on
the six sets of samples. Note the increase in suspended solids
on passage through the- aerated lagoon, an average from 340 to
580 mg/1. The polishing pond improved reductions very little,
especially during the last three weeks when it was full of
sludge.
Data collected on inorganic nutrients, nitrogen, and phos-
phates, is shown in Table 11. Total Kjeldahl nitrogen averaged
about 48 mg/1 in the waste stream entering the lagoon and total
phosphates averaged 26 mg/1. Nearly all of the orthophosphate
was incorporated into biological floe upon passage through the
aerated lagoon. There was about 9 mg/1 in the influent and only
0.2 mg/1 in the lagoon effluent.
The pH, alkalinity, and organic carbon data are shown in
Table 12. The lagoon acted as a buffering system as it evened
out the pH fluctuations of the incoming waste. There was a
slight increase in total alkalinity upon passage through the
lagoon from 260 to 270 mg/1 as CaCC>3-
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All COD and 6005 data collected are shown in Table 13. The
average BOD of the aerated lagoon influent was 820 mg/1 and the
effluents from the lagoon and the polishing pond averaged 196 and
182 mg/1, respectively. BOD of the supernatant following centri-
fuging averaged about 30 mg/1 for both effluents. On July 20,
when only 2 aerators were in operation, the soluble BOD was over
100 mg/1. On the effluent samples from July 27 to August 17, when
all 4 aerators were operating, the soluble BOD averaged about 10
mg/1. The polishing pond did not alter the COD reductions signifi-
cantly as its influent averaged 580 and the effluent averaged 550 mg/1.
Sphaerotilus, the filamentous bacterium commonly seen as a
gray slime growth in streams, was present in all samples from the
lagoon and polishing pond effluents. On July 13 and 20, the majority
of the filaments were short, less than 15 microns long. The density
ranged from about 350,000 per milliliter on July 13 to over 2,000,000
per milliliter on July 20. In the samples collected on July 27, the
biological floe was much denser and the Sphaerotilus appeared as long
intertwined filaments. This was also the case for the samples col-
lected on August 3, 10, and 17.
Several types of protozoans were identified along with a few
green attached and planktonic algae. On July 13 and 20 all of the
protozoans identified were flagellates. In the samples collected
on the last four sampling days, attached ciliates, crawling ciliates,
free-swimming ciliates, and rhiezopods were also found but the
flagellates continued to account for more than 70 percent of the
protozoans.
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EVALUATION OF TREATMENT OPERATIONS
The quantity of water used per 1,000 pounds of peas
processed varied from 2,900 to 5,300 gallons and averaged
3,500 gallons. Based on the analyses of the aerated lagoon
influent (after screening), the contribution of SS, BOD, and
COD per 1,000 pounds of peas processed averaged 10, 24, and
41 pounds, respectively. The range for SS was from 7 to 17.5
pounds, for BOD 18.5 to 31 pounds, and for COD 33 to 48 pounds,
In general, as the total quantity of peas processed per shift
increased, the contributions of flow, SS, BOD, and COD per
1,000 pounds decreased.
Table 14 presents the average percent reduction in the
various parameters analyzed on the composite samples. The
polishing pond was of very little benefit as shown by the dif-
ference between the reductions across the aerated lagoon and
the reductions across the aerated lagoon plus the polishing
pond. During the first few days of operation, the polishing
pond did remove some suspended solids which also increased the
organic removal somewhat, but the pond rapidly filled with
solids and no further benefit was obtained.
The total volatile solids were reduced about 50 percent
but both the suspended solids and the volatile suspended
solids increased substantially. Total phosphate and total
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nitrogen were not reduced significantly, but this was expected
since the aerated lagoon was completely mixed and the polishing
pond readily filled with the bulking solids. Total organic carbon,
COD, and BOD were reduced by 66, 59, and 76 percent, respectively.
The dissolved BOD was reduced by 96 percent for the entire period
and by 98 percent for the period when four aerators were in oper-
ation.
Inasmuch as most of the BOD in the effluent samples was
associated with the suspended solids, the overall treatment effi-
ciency could have been markedly improved by a good solids removal
step following the aerated lagoon. Normally this could be done
rather easily, much as initially planned, by returning solids from
the polishing pond back to the aerated lagoon. Once the suspended
solids reach the condition where sedimentation is very slow (high
SVI), good solids removal becomes almost impossible. This con-
dition was present on August 3, 10, and 17- The reason or reasons
why this condition is brought on were not pinpointed in this study.
One possible explanation lies in the organic loading pattern.
When the pea processing starts up initially, a large volume of
high-strength wastes is discharged to the aerated lagoon. Al-
though sufficient oxygen may be added to the lagoon, the food
to micro-organism (F/M) ratio is very high since relatively little
biological life is present in the lagoon. On July 20, the F/M
ratio was about 0.8 pounds of BOD per day per pound of volatile
suspended solids in the lagoon. Depending upon the type of waste
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being treated, F/M ratios between 0.5 and 1.0 lead to growth
of filamentous organisms which in turn cause bulking sludge.
During the four sampling periods which all aerators were in
operation, the F/M ratio ranged from 0.22 to 0.34 and averaged
0.28. In this range the likelihood of causing filamentous
growths is probably much less although the critical ratio for
this specific waste was not determined from this study.
The fact that less than four aerators are used during
the first week or two of pea processing accentuates the load-
ing problem. With only two or three aerators in operation,
the aerated lagoon does not function as a complete-mixed system
since most of the large biological floe will settle out in the
lagoon. This, in turn, results in higher F/M ratios. The
biological floe or suspended solids are also needed to absorb
dissolved organics to minimize foaming problems. During the
sampling on July 13 and 20, when less than four aerators were
operating, two to three feet of foam covered most of the aerated
lagoon. On successive sampling days when all four aerators
were in operation, virtually no foam was in evidence on the
lagoon. Use of four aerators markedly increased the solids in
suspension which, in turn, absorbed more dissolved organics thereby
eliminating the foam problem.
The BOD:N:P ratio averaged 100:5.8:1.0 for the five days
of sampling for which BOD's were run. A range from 100:5.1 to
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100:6.4 was observed for BOD:N ratio and the BOD:P ratio varied
from 100:0.8 to 100:1.2. The most commonly quoted ratio de-
picting inorganic nutrient requirements for aerobic biological
treatment is 100:5:1. Assuming all of the total Kjeldahl nitro-
gen and all of the total phosphate was available for biological
synthesis, the average ratios observed indicate that the inorganic
nutrients levels were adequate. Usually some of the organic
nitrogen and the phosphates are present in a form not readily
available for cell synthesis. This, coupled with the fact that
the ratios on several samples were less than optimum, indicates
that possibly some nutrient addition, especially phosphate,
might improve the degree of treatment obtained by the facility.
In a completely mixed basin, the BOD removal relationship
has been shown by W.W. Eckenfelder, Jr.,^ ' to be:
Sa-Se = k Se (1)
Xat
where:
Sa = influent BOD
Se = soluble BOD in effluent
Xa = MLSS
t = aeration time
k = removal rate coefficient
the solids in the basin (MLSS) and in the effluent are
Xa = So + aSr (2)
1 + bt
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where:
So = influent suspended solids
a = yield coefficient, synthesis per unit sub-
strate removed.
b = cellular auto-oxidation rate, fraction per
day.
Total BOD in the effluent from the completely mixed basin will be:
BOD = Se + c(Xa) (3)
where:
c = fractional BOD equivalent of suspended solids
in the effluent.
These three equations were used along with the results from the
analyses of the samples from July 27 to August 17, the period when
all four aerators were in operation, to determine values for the
four constants. The values obtained were:
k = 0.018
a = 0.70
b = 0.027
c = 0.24
The following tabulation shows both the calculated and measured
values in mg/1 for the soluble effluent BOD (Se), effluent sus-
pended solids (Xa) and total effluent BOD.
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Date
7-20-67
7-27-67
8-3-67
8-10-67
8-17-67
Soluble
Calcu.
12
12
10
10
9
BOD
Meas.
140
5
11
11
8
Sus.
Calcu.
800
700
890
730
720
Solids
Meas .
240
650
830
800
770
Total
Calcu.
205
180
225
185
180
BOD
Meas .
240
140
260
190
150
A.V6 TT3.2S 7 ~ 2 7
to 8-17 10 9 760 760 190 185
Also shown are the calculated and measured values for July 20,
when only two aerators were in operation. The calculated MLSS
was 800 mg/1 and the observed value was 240 which accounts for
the measured soluble BOD in the effluent of 140 mg/1 compared to
a calculated value of 12 mg/1. It was coincidental that the cal-
culated total BOD was fairly close to the measured, 205 versus
240 mg/1. For the four days when all the aerators were in oper-
ation, calculated and measured values agree fairly well. Percen-
tage-wise, the largest error was. in the soluble BOD but the accuracy
of the test in the 10 mg/1 area is rather poor. All suspended
solids results agreed within ten percent and the BODs agreed with-
in 20 percent except for the July 27 values. This may be partially
explained by the fact that all four aerators were not placed in
operation until July 26. On the average, agreement was very good
considering only one shift per week was sampled.
These constants can also be used to determine the degree of
suspended solids removal that would be required to obtain a speci-
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fied effluent BOD. For example, if 90 percent BOD reduction was
required, the total effluent BOD would have to be about 80 mg/1.
With about 10 mg/1 of soluble BOD, the effluent suspended solids
would have to be reduced to:
Eff SS = 80-10 = 290 mg/1
0.24
or the aerated lagoon effluent suspended solids would be reduced
by 62 percent. This could readily be accomplished by many con-
ventional clarification systems as long as a low SVI was maintained
through proper operation of the treatment facility.
The problems of foaming, possible inorganic nutrient deficiency,
low suspended solids reduction and high F/M ratio which cause
sludge bulking could be partially solved by the following operation
of the system:
Prior to startup of pea processing, all four aerators should
be placed in operation, at least intermittently. The number of
hours operation per day will depend upon the quantity and strength
of the wastes being produced at that time. A solids recirculation
pump should be installed and also started when the aerators are
placed in operation. This will allow the buildup of some solids
in the aerated lagoon before the pea wastes are introduced which
will aid in absorbing dissolved organics and maintain the F/M
ratio as low as possible. Once pea processing has started, contin-
uous recycle of suspended solids from the polishing pond back to
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the aerated lagoon will reduce foaming, possibly hold the F/M
ratio low enough to stop the filamentous growth, return some inor-
ganic nutrients to the aerated lagoon through auto-oxidation, and
increase both the suspended solids reduction and total BOD reduc-
tion. There would be some increase in oxygen demand in the aerated
lagoon due to the sludge recycle, but the present aerators should
be able to cope with it. The main unanswered question is whether
enough solids can be built up in the aerated lagoon prior to the
two critical periods (start of pea processing and change from one
to two shifts per day) to keep the F/M ratio low enough to eliminate
the filamentous growths. If this cannot be accomplished, then the
use of a holding tank before the aerated lagoon may be advisable
to spread the load out during the two critical periods.
Since the polishing pond was not designed specifically for
solids removal, it will be difficult to return most of the settled
solids to the aerated lagoon. Multiple draw-off points in the
lagoon bottom will be needed either through the use of separate
lines or a line with several openings. Prior to the start of pea
processing, the sludge return could be pumped intermittently
depending upon the quantity and quality of solids in the effluent
from the aerated lagoon.
The waste treatment facility is an efficient and economical
method of treatment. With some modifications, both the SS and BOD
reductions could be markedly improved.
-------
25
Additional studies of this type are needed to more fully
assess problems associated with biological treatment of seasonal
industries such as food processing. Rapidly changing hydraulic
and organic loads, and inorganic nutrient concentrations cause
many operational problems in waste treatment. These problems
will need solutions before higher levels of treatment can be
obtained.
-------
27
BIBLIOGRAPHY
Unpublished information from the State of Washington Water
Pollution Control Commission.
1. Gellman, I., "Aerated Stabilization Basin Treatment of Mill
Effluents," TAPPI, 48, 106A (1965)
2. Standard Methods for the Examination of Water and Wastewater,
12th Edition, 1965, Boyd Printing Co., Inc., Albany,
New York.
3. Jenkins, P. and Medsker, L. L., "Brucine Method for the Deter-
mination of Nitrate in Ocean, Estuarine, and Fresh Water."
Analytical Chemistry, 36, 610 (1964)
4. Anonymous, Aminco Reprint No. 104. American Instrument Co.,
Inc. June 1959.
5. Strickland, J. D. H. and Parsons, T. R., "A Manual of Sea Water
Analysis." Bulletin No. 125, Second Ed., pg. 47, Revised
Fisheries Research Board of Canada.
6. ASTM D-2579-T, Issued 1967. Published by ASTM 1916, Race St.,
Philadelphia, Pennsylvania.
7. Murray, H. R. and Okey, R. W., "An Analysis of Aerated Lagoon
Operation for Vegetable Wastes at Ferndale, Washington."
8. Eckenfelder, W. W., Jr., "New Design Advances in Biological
Treatment of Industrial Wastes," Presented at 17th Annual
Oklahoma Ind. Wastes and Pollution Control Conference,
November 15, 1966.
-------
APPENDIX
-------
STATE OF WASHINGTON
POLLUTION CONTROL COMMISSION
4O9 PUBLIC HTA1-TH DUILDtNG
OLYMf.A, WASHINGTON
January 19. 1966
Mr. R. F. Poston, Offieer-in-Charga
Federal Water Pollution Control Administration
Rocn 570 Pittock Block
Portland, Orecon 97205
Dear Hr. PCStonj
Ws understand that a research project on aerated lagoons is being proposed
for tha Federal Water Pollution Control Administration laboratory ia
Corvallia.
Uc heartily support research in the Northwest on lagoons of this typa
bscauf-a there itt at present a scarcity of good, reliable data for facility
dc.-isn, and we believe that £heoo Byatcras havo & promising future for
economical tre«tracnt of largo organic wasto loads. At present there, are
thrco aerated la£°cns £n Washington treating pulp alii, vegetable., end
fruit process wastes,, end withia tha jpaat few taoatha wo have r©vict?ed
pinna for six additional fficilitlos of this gsmaral type. Consequently,
fa hive a very distinct need for additional performance and dasijrn
infomntion.
I* va csn ba of sssiotanco in the development or implessentatioa of such
research, please call on us at your convenience.
Very truly yours,
a
Director
K.MK:JPB:cJ
cc: Mr. Boydoton
FWPCA - Corvallia
-------
-------
+^o
\
10
I -20
5
•JULY /3, /967
A,
8-'OO
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IQ-.OO
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6--00
PM
F/GURE 2. VAX i AT 10 tJ /A/
U*e
-------
/oo
1
I
1
ao
60
4O
JULY 27
4O
30
120 /60 2OO
T/M£ - A* /A/(JT£S
240
2&0
-------
34
Table 1
(a)
FOODS PROCESSED AND WATER USED
Processed - Ibs. Water Used No. of
Date Peas Raspberries Gals. Aerators
7-13-67
7-20-67
7-27-67
8-3-67
8-10-67
8-17-67
159,500
128,000
145,500
180,500
175,000
96,100
0
9,100
21,200
4,700
300
0
563,000
545,000
518,000
456,000
502,000
506,000
3
2
4
4
4
4
Average: 147,400 515,000
(a) Values for 1 shift (8:00 A.M. - 7:00 P.M.)
-------
35
Table 2
TEMPERATURE AND pH DATA
JULY 13, 1967
Lagoon Influent Lagoon Effluent Pond Effluent
Time
0800
0930
1030
1130
1230
1330
1430
1530
1630
1730
Temp.
19
20
20
17.5
20.5
17
19
20
19.5
18
2H
7.5
7.6
7.7
7.7
7.3
7.7
7.9
7.7
7.9
7.7
Temp.
20
20
20
20
20.5
21.5
21.5
22
22
22
£H
7.4
7.2
7.4
7.4
7.3
7.3
7.6
7.5
7.6
7.5
Temp.
19.5
19.5
20
20
21.5
22
22.5
22.5
22.5
22
2S
7.2
7.3
7.4
7.4
7.4
7.3
7.6
7.4
7.4
7.6
-------
36
Table 3
TEMPERATURE AND pH DATA
JULY 20, 1967
Lagoon Influent Lagoon Effluent Pond Effluent
Time
0815
0845
0915
0945
1045
1115
1145
1215
1245
1315
1345
1415
1445
1515
1615
1715
1745
1815
Temp.
21
20
18.5
18.5
19
19
20
20
21
20
19.5
19
19
18.5
21
18.5
17
17
2H
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
.5
.5
.5
.4
.3
.3
.4
.3
.3
.4
.4
.5
.4
.5
.4
.4
Temp.
21
21
21
21
21
21
21
21
21
21
21
21
21
pH
7
7
7
7
7
7
7
7
7
7
7
7
.1
.3
.2
.1
.2
.2
.2
.1
.2
.1
.1
.2
Temp.
21
20
20.5
20.5
20.5
21
21
21
21
21
21
21
21
2!
7
7
7
7
7
7
7
7
7
7
7
7
.1
.1
.2
.0
.1
.1
.1
.0
.1
.1
.0
.1
-------
37
Table 4
TEMPERATURE AND pH DATA
JULY 27, 1967
Lagoon Influent Lagoon Effluent Pond Effluent
Time
0815
0915
1015
1115
1215
1315
1415
1515
1615
1715
1815
Temp.
20
20.5
20.5
20
21
18
22.5
24
22.5
23
20
£H
7.4
7.3
7.4
7.5
7.4
7.6
7.0
6.7
7.0
6.7
7.0
Temp.
19.5
20
20
20
20
20
20.5
20.5
20.5
21
21
£H
7.3
7.3
7.3
7.4
7.3
7.2
7.0
6.6
6.9
6.9
7.0
Temp.
19.5
20
20
20
20
20
20.5
20.5
21
21
21
£S
7.3
7.3
7.3
7.4
7.3
7.2
7.0
6.5
6.5
6.7
6.9
-------
38
Table 5
TEMPERATURE AND pH DATA
AUGUST 3, 1967
Lagoon Influent Lagoon Effluent Pond Effluent
j>H Temp. pH
7.5 20.5 7.5
Time
0815
0830
0845
0915
0930
1015
1030
1115
1130
1215
1230
1245
1315
1345
1415
1430
1515
1530
Temp.
19.5
20
20
22
20
24.5
26
24.5
24
25
26
pH Temp
7.8
20
7.5
7.5
20.5
7.4
22
7.5
22
7.6
21.5
7.7
7.6
7.7
7.7
23
7.6
23
7.5 21 7.3
7.4 21.5 7.2
7.4 21 7.3
7.4 23 7.2
7.6 24 7.5
7.7 23 7.4
-------
Time
1545
1615
1630
1645
1730
1745
1815
1830
Tern]
26
26
22
29.!
27
39
Table 5 (Cont.)
TEMPERATURE AND pH DATA
AUGUST 3, 1967
Lagoon Influent Lagoon Effluent Pond Effluent
jgH Temp. j>H Temp. j>H
7.6
7.6
23 7.6 24 7.7
7.7
23 7.7 23 7.7
7.7
7.9
23 7.6 23 7.6
-------
40
Table 6
TEMPERATURE AND pH DATA
AUGUST 10, 1967
Time
0815
0915
1015
1115
1215
1315
1415
1515
1615
1715
1815
o —
Temp.
19
21.5
19.5
21.5
21
21
23
22.5
24
18
21.5
£H
7.9
7.8
7.8
7.6
7.8
7.7
7.2
7.3
7.7
7.3
7.5
Temp.
20
20.5
21
21.5
22
22
22.5
22.5
22
23
22.5
£H
7.8
7.7
7.7
7.7
7.5
7.6
7.5
7.5
7.4
7.4
7.5
Temp.
20.5
21
21
21.5
22
22
22.5
22.5
22.5
23
22.5
J3H
7.9
7.6
7.7
7.7
7.4
7.4
7.5
7.5
7.5
7.4
7.5
-------
41
Table 7
TEMPERATURE AND pH DATA
AUGUST 17, 1967
Lagoon Influent Lagoon Effluent Pond Effluent
Time
0815
0915
1015
1115
1215
1315
1415
1515
1615
1715
1815
Temp.
20
20
20.5
21
21
21
20.5
20.5
21
21
18
£H
8.2
7.9
7.9
7.3
7.5
7.8
7.6
7.5
7.5
7.5
7,8
Temp.
21
21
21
21.5
21.5
21.5
21.5
21.5
21.5
22
21.5
2H
8.1
8.0
7.9
7.7
7.5
7.5
7.5
7.6
7.7
7.5
7.6
Temp.
21
21
21.5
21.5
22
22
22
21.5
22
22
21
2H
7.7
7.5
7.7
7.5
7.3
7.3
7.4
7.4
7.3
7.4
7.4
-------
42
Table 8
Date Time
7-13-67 1145
1545
7-20-67 1030
1500
1715
8-3-67 1100
1500
LAGOON TEMPERATURE DATA, °C
Depth
ft.
1
1
1
1
1
1
8
1
8
ill
20
22
20
20
20
19
19
22
21.5
SAMPLING STATION
(2) (3) (4)
20 20 20
21.5
20.5
20.5
20.5
19.5
20
20.5
21
21.5
20
20
20.5
19.5
20
20.5
20.5
22.5
19.5
19.5
20
19.5
20
20.5
21
151
20
22
—
—
—
—
—
22
«•
-------
43
Table 9
LAGOON DISSOLVED OXYGEN DATA, mg/1
Depth SAMPLING STATION
Date
7-13-67
7-20-67
7-27-67
8-3-67
8-10-67*
Time
1145
1545
1030
1500
1715
1130
1530
1730
1100
1500
1000
1300
ft.
1
1
1
5
1
5
1
5
1
8
1
8
1
8
1
8
1
8
1
1
111
0.3
0.3
0.1
0.1
0.2
0.1
0.3
0.1
2.6
2.0
3.0
2.4
3.8
3.5
5.2
3.7
4.7
4.5
121
0.9
1.0
0.2
0.9
0.1
0.9
0.2
3.4
2.3
2.7
1.6
4.0
3.4
3.9
4.0
5.0
4.8
ill
0.6
1.4
0.1
0.2
0.2
0.1
0.2
0.1
3.8
3.5
3.7
2.3
3.8
3.4
4.3
4.1
5.6
5.3
(4) (5) (6)
1.2 0.3
2.4 0.3
0.6
1.1
0.3
0.7
0.3
4.6 3.8
3.8
4.9 4.8
3.7
4.4 4.8
4.4
5.2
4.8
6.3 1.8
5.9
1.7 1.3
1.7 1.4
-------
44
Table 9 (Cont.)
LAGOON DISSOLVED OXYGEN DATA, mg/1
Depth SAMPLING STATION
Date Time ft. (1) (2) (3) (4) (5) (6)
1.8 1.4
0.6
0.6
0.6
1600
1100
1500
1700
1
1
8
1
8
1
8
0.7
0.6
0.6
0.6
0.6
0.6
0.7
0.7
0.6
0.6
0.7
0.7
0.6
0.6
0.6
0.6
0.6
0.6
0.7
0.7
0.7
0.7
0.7
0.7
D.O. run by Winkler^ ' method.
-------
Table 10
SOLIDS DATA, mg/1
45
7-20-67
7-27-67
8-3-67
8-10-67
8-17-67
Location T.S. T.V.S. S.S. V.S.S.
Lagoon Influent 2460 1610 440 270
Lagoon Effluent 1950 1220 280 220
Pond Effluent 1970 1160 150 120
Lagoon Influent 2850 1450 310
Lagoon Effluent 1940 560 240
Pond Effluent 1860 510 180
Lagoon Influent 2560 1380 250 160
Lagoon Effluent 2250 680 650 440
Pond Effluent 2000 500 440 310
Lagoon Influent 2830 1540 330 180
Lagoon Effluent 2330 680 830 550
Pond Effluent 2330 670 820 540
Lagoon Influent 3120 1350 300 110
Lagoon Effluent 2460 680 800 500
Pond Effluent 2400 650 790 520
Lagoon Influent 2760 1110 400 230
Lagoon Effluent 2330 640 770 510
Pond Effluent 2340 660 740 490
Average Overall:
Lagoon Influent
Lagoon Effluent
Pond Effluent
7-27 to 8-17:
Lagoon Influent
Lagoon Effluent
Pond Effluent
2760 1410
2210 740
2150 690
340
580
520
320
760
700
190
440
400
170
500
465
-------
46
Table 11
INORGANIC NUTRIENT DATA
Date Location NH-N T.K.-N
7-13-67 Lagoon Influent 4.0 49.6
Lagoon Effluent 0.7 31.9
Pond Effluent 0.4 26.6
7-20-67 Lagoon Influent 3.1 44.0 21.7 9.1
Lagoon Effluent 0.5 23.6 12.6 0.2
Pond Effluent 2.2 20.6 9.6 0.1
7-27-67 Lagoon Influent 3.6 52.1 24.5 14.0
Lagoon Effluent 1.1 44.0 22.9 0.1
Pond Effluent 4.1 32.6 18.3 0.2
8-3-67 Lagoon Influent 4.2 53.0 39.1 12.7
Lagoon Effluent 1.5 53.0 40.9 0.1
Pond Effluent 3.7 53.0 43.9 0.2
8-10-67 Lagoon Influent 3.2 48.1 20.4 4.1
Lagoon Effluent 5.9 48.1 24.3 0.3
Pond Effluent 5.6 51.6 19.5 0.1
8-17-67 Lagoon Influent 2.8 38.0 17.0 5.5
Lagoon Effluent 3.3 64.3 22.5 0.2
Pond Effluent 6.7 61.4 24.3 0.9
Average:
Lagoon Influent 3.5 47.5 25.6 8.6
Lagoon Effluent 2.2 44.2 23.3 0.2
Pond Effluent 3.8 39.4 21.7 0.3
-------
47
Table 12
ORGANIC CARBON, pH AND ALKALINITY DATA
Date Location pH Alk. TOG DOC
7-13-67 Lagoon Influent 640
Lagoon Effluent 7.3 280 200
Pond Effluent 7.3 280 170
7-20-67 Lagoon Influent 7.7 250 560
Lagoon Effluent 7.1 270 160
Pond Effluent 7.1 270 190
7-27-67 Lagoon Influent 7.8 250
Lagoon Effluent 7.5 270 190
Pond Effluent 7.5 290 150
8-3-67 Lagoon Influent 7.6 260 570
Lagoon Effluent 7.5 270 230
Pond Effluent 7.5 280 200
8-10-67 Lagoon Influent 7.8 270 540
Lagoon Effluent 7.6 290 170
Pond Effluent 7.6 290 180
8-17-67 Lagoon Influent 7.0 260 400 280
Lagoon Effluent 7.2 260 160 24
Pond Effluent 7.3 300 130 23
Average:
Lagoon Influent 260 540
Lagoon Effluent 270 185
Pond Effluent 285 170
-------
48
Table 13
BOD AND COD DATA
Date
Location
BOD
Total Dissolved
COD
Total Dissolved
7-13-67
7-20-67
7-27-67
8-3-67
Lagoon Influent
Lagoon Effluent
Pond Effluent
Lagoon Influent
Lagoon Effluent
Pond Effluent
870
240
190
Lagoon Influent 810
Lagoon Effluent 140
Pond Effluent 140
Lagoon Influent 1020
Lagoon Effluent 260
Pond Effluent 260
870
140
110
740
5
12
850
11
7
1470
510
430
1350
410
310
1540
650
490
1580
650
670
1500
160
170
8-10-67 Lagoon Influent 780
Lagoon Effluent 190
Pond Effluent 150
8-17-67 Lagoon Influent 620
Lagoon Effluent 150
Pond Effluent 170
710
11
11
550
8
16
1540
740
740
1060
540
640
1370
150
1000
120
120
Average Overall:
Lagoon Influent 820
Lagoon Effluent 196
Pond Effluent 182
745
35
31
1420
580
550
1290
140
150
7-27 to 8-17:
Lagoon Influent 810
Lagoon Effluent 185
Pond Effluent 180
570
9
12
1410
640
640
-------
49
Table 14
AVERAGE PERCENT REDUCTIONS
Parameter
Total Solids
Total Volatile Solids
Suspended Solids
Volatile Suspended Solids
Total Phosphate
Total Kjeldahl Nitrogen
Total Organic Carbon
Dissolved Organic Carbon
COD, Total
COD, Dissolved
BOD, Total
BOD, Dissolved
Overall
7-27 to 8-17
Aerated
Lagoon
20
48
-71
-132
9
7
66
91
59
82
76
95
Lagoon &
Polishing
Pond
22
51
-53
-110
15
17
69
92
62
89
78
96
98.4
98
------- |