WATER POLLUTION CONTROL RESEARCH SERIES • 17010DXD08/70
PHOSPHOROUS REMOVAL
BY AN
ACTIVATED SLUDGE PLANT
U.S. ENVIRONMENTAL PROTECTION AGENCY
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WATER POLLUTION CONTROL RESEARCH SERIES
The Water Pollution Control Research Series describes the
results and progress in the control and abatement of pollution
in our Nation's waters. They provide a central source of
information on the research, development and demonstration
activities in the Environmental Protection Agency, through
inhouse research and grants and contracts with Federal,
State, and local agencies, research institutions, and
industrial organizations.
Inquiries pertaining to Water Pollution Control Research
Reports should be directed to the Chief, Publications Branch
(Water), Research Information Division, R&M, Environmental
Protection Agency, Washington, B.C. 20U60.
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PHOSPHORUS REMOVAL BY AN ACTIVATED SLUDGE PLANT
by
Sewerage Commission of the City of Milwaukee
Milwaukee, Wisconsin 53201
for the
ENVIRONMENTAL PROTECTION AGENCY
Program #17010 DXD
Grant #WPD 188-01-67
188-02-68
188-03-69
August, 1970
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 - Prlco {1.00
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EPA Review Notice
This report has been reviewed by the
EPA, and approved for publication.
Approval does not signify that the con-
tents necessarily reflect the views and
policies of the Environmental Protection
Agency, nor does mention of trade names or
commercial products constitute endorsement
or recommendation for use.
ii
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ABSTRACT
The Milwaukee plants removed an average of 80$ of the influent total
phosphorus (TP). Milwaukee offered an opportunity for plant scale
demonstration and study of the activated sludge process parameters
effects on TP removal.
The high TP removals were due to sufficient solids production from
the amounts of TP, BOD and suspended solids in Milwaukee sewage.
Phosphorus balances demonstrated an average of 95.7$ of the phospho-
rus removed was recovered in the waste sludge withdrawn as Milorganite.
An equation was developed for predicting % TP removal from East Plant
(EP) 1968 data. Applied to 1969 and 1970 data when TP removals
exceeded 80$, the significant parameters were food to microorganisms
(F/M), MLSS, and TP to microorganisms (TP/M). The significance of
ML-DO, air application rate and detention time could not be shown.
Plant scale studies revealed that F/M, MLSS and TP/M mainly affected
soluble orthophosphate (SOP) removal. The removal of SOP was
associated with MLSS biological activity by oxygen uptake rate
measurements in tank studies. A ML-DO^ 2.0 mg/L past the tank turn-
point was effective for SOP removal. Insolubilization of SOP by
sewage soluble cations appeared to be insignificant in the process.
It appears that brewery waste water aids soluble phosphorus removal
at the Milwaukee plants.
The cyclic removal of TP in an activated sludge plant was shown by
the analyses of hourly influent and effluent samples for BOD, TP and
SOP during a year's study. These cycles corresponded to the hourly
changes in sewage composition and flows and clarifier sludge blanket
build-up. At times TP removal efficiency was greatly reduced by the
loss of solids from overloaded clarifiers at peak flows.
Continuous addition of ferrous sulfate waste pickle liquor to EP-ML
at a 15 mg/L-Fe rate provided hourly effluent soluble phosphorus
residuals of 0.05 mg/L-P. X-ray diffraction studies of freeze dried
sludges showed iron present as vivianite.
This report was submitted in fulfillment of Grant Ho. WPD 188-01-67,
188-02-68, and 188-03-69, Program No. 17010 DXD, between the Federal
Water Quality Administration (now Environmental Protection Agency) and
the Sewerage Commission of the City of Milwaukee, Wisconsin.
Key Words: Phosphorus removal, activated sludge process, process
parameters, wastewater treatment, biological treatment.
iii
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CONTENTS
Section
Abstract
Contents v
List of Figures vii
List of Tables ix
List of Appendices xi
I Conclusions 1
II Recommendations 3
III Introduction 5
IV Literature Survey 7
V Procedures
A. Milwaukee Waste Water Treatment Facilities 11
at Jones Island
B. Sampling and Analytical Techniques 13
VI Research Phases, Results & Discussion
A. Correlation of Activated Sludge Process 15
Parameters to Phosphorus Removal on a
Plant Scale :
B. Demonstration of Cyclic Removal of Phosphorus 19
from Sewage by an Activated Sludge Plant
C. Plant Study of the Effect of Clarifier Blanket 23
Depths on Clarifier Effluent Residual SOP
D. Plant Loading Study (F/M and TP/M) 26
E. Effect of Brewery Waste Load 30
F. Plant Scale Phosphorus Balances 36
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CONTENTS
Section Page
G. Relationship Between the Removal of Total BOD 38
and Removal of TSP in an Activated Sludge
Plant (BODR/TSP/R)
H. Study of Soluble Phosphorus Uptake in East Plant 41
Aeration Tanks (General)
I. Effect of MLSS-02 Uptake Rates and Air Appli- 42
cation Rates on Soluble Phosphorus Uptake in an
Aeration Tank
J. Evaluation of MLSS Activity by Glucose Dehydro- 52
genase Assay
K. X-Ray Diffraction Studies of Sewage Suspended 55
Solids and Waste Sludge Solids
L. Cationic Removal of Phosphorus from Sewage 57
M. Effect of Iron Addition to an Aeration Tank on 60
Soluble Phosphorus Removal
N. Plant Scale Iron Addition Study 66
VII Acknowledgements 77
VIII References . 79
IX Nomenclature and Glossary 83
X Appendices 85
VI
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FIGURES
PAGE
1. JONES ISLAND SEWAGE TREATMENT PLANT 12
2. SEWAGE AND EFFLUENT AVERAGE HOURLY COMPOSITION 20
13/3/67 to 6/15/68
3. SOP RELEASE AND DIFFUSION FROM SLUDGE BLANKET 24
VERSUS TIME
1*. EFFECT OF PLANT LOADINGS ON PLANT EFFLUENT 28
SOP LEVELS
5. EFFECT OF BREWERIES SHUTDOWN ON RS COMPOSITION 33.
6. FREQUENCY DISTRIBUTION BODR/TSPR WEEKDAY DATA 39
7. FREQUENCY DISTRIBUTION BODR/TSPR WEEKEND DATA 40
8. AERATION TANKS DO PROFILES (9-30-1969, 8:00 A.M.) 43
9. AERATION TANKS DO PROFILES (10-6-1969, 12:30 P.M.) 45
10. EFFECT OF AIR APPLICATION RATE ON ML-DO LEVEL 47
.11. EFFECT OF AIR APPLICATION RATE ON MLSS-02 UPTAKE RATE 48
12. EFFECT OF AIR APPLICATION RATE ON ML-TSP LEVEL 49
13. EFFECT OF AIR APPLICATION RATE ON ML-SOLUBLE BOD LEVEL 50
lU. EFFECT OF IRON ADDITION ON EAST PLANT RESIDUAL SOP 68
15. COMPARISON OF EAST AND WEST PLANT SDI'S 69
16. ACCUMULATION OF IRON IN EP-RS 71
17. RETURN SLUDGE ASH CONTENT (DRY BASIS) 72
18. RETURN SLUDGE NITROGEN CONTENT (DRY BASIS) 73
19. TECHNICON AUTOANALYZER SCHEMATIC 87
vii
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TABLES
Table Page
1. Effect of Clarifier Sludge Blanket Depths on 22
East Plant Effluent Quality
2. Comparison of SOP Concentration (mg/L-P) of Aeration 25
Tank No. 10 Outlet ML, Clarifier No. 5 ML - Feed,
Clarifier No. 5 Effluent in Relation to Clarifier
Blanket Depth
3. Averages of Daily Data by Periods 27
U. Summary Period Averages 31
5. Comparison of Period Averages 32
6. Relation of Phosphorus Removed to Solids Synthesis 35
7. Calculated Weekly Phosphorus Recoveries 37
8. Average BODR/TSPR Ratios 38
9. Air Application Rates 42
10. Effect of Air Application Rates 44
11. Daily Process Parameter Data 46
12. MLSS-02 Uptake Rate After Six Hours Aeration 51
13. Dehydrogenase Assay Variability 53
lU. Dehydrogenase Assay Data 53
15. Variability of ML - Dehydrogenase Activity and MLVSS 54
at Different Sample Locations
16. Comparison of Coefficients of Variation (C.V.) 54
17. Average Cation Concentrations (mg/L) for July, 19^9 58
18. Effect of Iron Dosage on ML - TSP Level 61
IX
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TABLES
Table Page
19. Run 6 Observation Data 62
20. Reduction of Soluble Iron Concentration in an 63
Aeration Tank
21. Average Iron Recoveries 64
22. Soluble Iron and TSP Release by MLSS 65
23. Effluent SOP (mg/L-P) 67
2l». Average Return Sludge Composition 75
25. Aerobic Digestion of Sludge 92
x
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APPENDICES
Appendix Title Page
A Phosphorus Determination with Technicon Autoanalyzer 85
B Procedure used for MLSS and RSSS Determination 88
C BOD Determination 89
D Discussion of Material Found Floating on the Surface 91
of the EP Aeration Tanks and the Aerobic Digestion
of Waste Sludge
E Average Daily Screened Sewage Characteristics and 94
Plant Operation Data
F Total Phosphorus Removal at the Jones Island Plants 95
Based on Plant Flows
xi
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SECTION I
CONCLUSIONS
A three-year plant scale study on the phosphorus removal by an acti-
vated sludge plant conducted at Jones Island Plant, Milwaukee, Wis-
consin, resulted in the following observations:
1. The Milwaukee plants on the average removed 80$ of the TP from
sewage. The effluent TP concentrations coincided with the hourly
changes in sewage composition and flow, and at times with the hourly
build-up of clarifier sludge blankets. The effluent TP concentrations
increased as the sewage flowJfr-BOD and TP concentrations increased.
Low effluent TP concentration^ w"ere usually observed with low sewage
flow, BOD and TP concentrations.
2. The relationship of tot&l-BOD removal to total soluble phosphorus
removal was found to vary according to the day of the week; on the
average, the ratios were 88:1 for weekdays, 62:1 for Saturdays, and
U7:l for Sundays. r
3. Weekly plant scale phosphorus balances during a 37 week study
showed that an average of 95.7$ of the sewage phosphorus removed by
both plants could be accounted for in the Milorganite produced.
This indicated that the removal of waste sludge (as Milorganite)
was the vehicle for withdrawal of phosphorus from the waste treat-
ment system.
k. Overloaded clarifiers at peak flows resulted in lower TP removals
due to spewing of solids over the weirs. However, the detention of
solids for 2 to 3 hours at different sludge blanket depths had very
little influence on the clarifier effluent SOP concentration.
5. A substantial release of SOP was observed when the RS was mixed
with the screened sewage. The concentration of SOP in the resulting
ML was 2 to 3 times greater than that expected from the calculated
amount in a corresponding mixture.
6. The removal of TSP by MLSS appears to be related to MLSS
metabolic activity as was shown by MLSS-02 uptake rate measurements
along the aeration tank.
7. A loading study with the two plants showed that an average F/M
and TP/M loadings of 0.291 and .011, respectively, resulted in slightly
higher average SOP removals compared to the higher average loadings of
0.51U and 0.019, respectively.
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8. There was a marked drop in the soluble phosphorus removal during
the shutdown of the Milwaukee breweries in 1969» compared with the
high soluble phosphorus removals before and after the shutdown. The
rapid recovery of soluble phosphorus removal by both plants indicates
the brewery waste water aids soluble phosphorus removal.
9. Aeration tank studies in the East Plant indicated that an air
application rate of 0.86 cu. ft./gal. of influent or larger and a
ML-DO of 2.0 mg/L beyond the tank turnpoint was adequate and effective
in reducing soluble BOD to 10 mg/L and TSP to 0.5 mg/L-P at MLSS
concentrations of 2530 to 2910 mg/L. A ML-DO of 1.0 mg/L beyond the
tank turnpoint did not result in as much SOP removal as was observed
with a ML-DO of 2.0 mg/L.
10. The quantity of insoluble phosphorus (58? for 1969) in Milwaukee
sewage is unusually high compared to normally reported values for
municipal waste waters. No significant differences were found in
influent and plant effluent soluble iron, aluminum, calcium and mag-
nesium concentrations. This indicated that very little insolubli-
zation of phosphorus by these cations occur in the activated sludge
process. It appears that the cationic fixation of phosphorus
probably occurs in the sewage prior to its reaching the plant.
11.. Limited X-ray diffraction studies on freeze dried WS samples
revealed that some of the iron in the WS was in the form of a crystal-
like iron orthophosphatet vivianite Peg (PO^Jp • SHgO.
12. Limited phosphorus removal studies with the addition of waste
pickle liquor to the mixed liquor indicated that enhanced SOP
removals can be achieved by iron addition. The waste pickle liquor
appeared to have no effect on the ML biota.
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SECTION II
RECOMMENDATIONS
The results of this three year study have shown that the
City of Milwaukee Sewerage Commission's East Plant can consistently
average Q0% total phosphorus removal from sewage. A short term study
of continuous iron addition, as ferrous sulfate waste pickle liquor,
to the East Plant has demonstrated the feasibility of a long term
plant study. The preliminary data indicated that it could be possible
to consistently produce a plant effluent with a TSP residual of
approximately 0.5 mg/L-P or less. It could also be possible to improve
the plant total phosphorus removal efficiency from an average of 80% to
an average of 90%•
A one year study to determine the long term effects of con-
tinuous iron addition on the 115 ngd East Plant and to compare its
performance to the 85 mgd West Plant which will receive no additional
iron is proposed. The effects of continuous iron addition upon mixed
liquor flora, mixed liquor settleability, waste sludge conditioning
requirements and plant physical facilities would be evaluated along
with effluent phosphorus and iron concentrations.
This would require the continuous feeding of ferrous iron
(as waste pickle liquor) to the mixed liquor feed channel of the
115 mgd East Plant. Twenty four hour composite samples of East and
West Plant effluent would be analyzed to determine the ability of
ferrous iron to increase phosphorus removal. Microscopic examination
of mixed liquor samples would be utilized to determine if iron
affected the mixed liquor culture.
Extension of the test period over one year would establish
the feasibility of iron addition as a method for enhanced sewage
phosphorus removal. If iron addition proves to be feasible it could
provide an economic method of phosphorus removal for existing acti-
vated sludge plants, and provide effluents with consistently low
phosphorus residuals.
The completed work has shown that excellent removal of
phosphorus from sewage can be obtained in an activated sludge plant.
However, due to the size of the operation (115 mgd) and limitations
in the method of waste sludge removal (fertilizer production) it was
extremely difficult to control and/or change the process parameters
on a day to day basis. It is therefore suggested that consideration
be given to modifying the East Plant. The modifications would be the
isolation of two aeration tanks and one clarifier and a separated
mixed liquor feed. This would provide a 12 mgd plant operated on its
own return sludge, in which all process parameters could be controlled
and varied as required to establish the mechanisms of phosphorus
fixation in the activated sludge process.
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SECTION III
INTRODUCTION
It has long been recognized that phosphates are one of the
major factors contributing to the progressive fertilization of streams
and lakes which result in frequent and highly objectionable algae
blooms.
Although over 9Q% of the biologically oxidizable organic
matter and suspended solids are removed in the conventional activated
sludge process, the reduction of dissolved mineral nutrients is gener-
ally very low. Most municipal plants employing the activated sludge
treatment process, report phosphorus removals from sewage of 20 to 30$.
There are a few exceptions, such as the Milwaukee (l), San Antonio
(2), and Baltimore (3) plants where phosphorus removals as high as 80$
to 96$ have been reported.
No significant conclusions have been reached as to the
reason for such wide variation in the effectiveness of the convention-
al activated sludge process to remove total phosphorus from sewage.
One group of investigators, Menar and Jenkins (U), hypothesized that
based on a normal BOD of about 200 mg/L and total phosphorus of
10 mg/L-P in sewage, the biological removal of phosphorus in the form
of waste activated sludge should be 20 to 30% and any additional re-
moval observed is the result of the insolublization of phosphate by
the soluble cations (mainly calcium and iron) present either in the
hard carriage waters or coming from steel industries or both. The
second group (Levin and Shapiro (5), and Vacker, et. al. (6)) hold
the theory that the activated sludge microorganisms under optimum
operating conditions can store phosphorus far in excess of their
metabolic requirements (100 BOD: IP) and have called this excess
uptake "luxury uptake".
The Milwaukee Jones Island plants have been consistently
showing good total phosphorus removals (usually over 80$). The two
plants (East and West) are operated in parallel and each plant treats
a part of the total flow. In 1967, the Federal Water Pollution Con-
trol Administration initiated a three year research and demonstration
project with the Sewerage Commission of the City of Milwaukee. The
objective of the study was to demonstrate and optimize the effects
of the activated sludge process parameters on a plant scale for the
removal of total phosphorus from sewage.
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SECTION IV
LITERATURE SURVEY
Sewage phosphorus removals by the activated sludge process
have been reported by a number of investigators, Owens (7) 2 to U6$,
Stone (8), 6U to 71$, for three Chicago waste water treatment plants
Hurwitz (9) reports removals of 76.7$, 36.6$, and 53.9$.Some of the
short term plant scale investigations made by the Federal Water
Pollution Administration as summarized by Witherow (3) have indicated
total phosphorus removals of 51 to 75$ in the Northside plant of
Amarillo and the Village Creek plant in Fort Worth. The Rilling plant
in San Antonio and the Back River plant in Baltimore have been report-
ed to consistently remove an average of 80$ and 90$ of the total
phosphorus respectively.
Phosphorus has also been successfully removed from waste
waters by using chemicals such as lime, alum, ferric chloride, ferric
sulfate, ferrous sulfate, and sodium aluminate. These chemicals have
been used to precipitate phosphorus in tertiary treatment by Owens (7),
Lea, et. al. (10), Rohlich (ll), Malhotra, et. al. (12) and Nesbitt
(13). Chemicals have also been used to insolublize phosphorus in the
biological treatment units by their addition to the aeration units,
Tenney and Stumm (lU), Barth and Ettinger (15), Eberhardt and Nesbitt
(l6), or by their addition prior to the primary sedimentation units,
Rudolf (17), Neil (l8), Schmid and McKinney (19).
A review of the current literature suggests that two schools
of thought are being used to explain the wide variation in the phospho-
rus removals observed at different plants in the United States. Sawyer
(20), Sekikawa, et. al. (21), Hall and Engelbrecht (22), Menar and
Jenkins (U), support the theory that the biologically incorporated
phosphorus in the activated sludge solids is between 2 to 3$ phosphorus
on the volatile mass basis and any additional removal is cationic.
Menar and Jenkins (U) indicate that biological phosphorus removal is not
affected by the sludge growth rate or by standard process operating
parameters and that the phosphorus removal is directly proportional to
the net sludge growth. This means that the phosphorus removed biologi-
cally in a conventional activated sludge sewage treatment plant would
be in the range of approximately 100 parts of BOD removed to 1 part of
soluble phosphorus removed. Based on an average BOD removal of 200 mg/L
and influent total phosphorus content of 10 mg/L-P, about 20 to 30$ of
the influent phosphorus would be removed biologically.
The second theory was presented in papers by Levin and
Shapiro (5), Borchardt and Azad (23), and Connell and Vacker (2); they
indicated that activated sludge solids under certain conditions were
capable of removing more phosphorus than they require for cell growth.
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The biological uptake of excess phosphorus was called "luxury uptake"
They reported that luxury uptake was enhanced by high ML-DO concen-
trations, and the phosphorus incorporated by this mechanism was re-
leased from the solids by anaercoic or acidic conditions. They report
ed that luxury uptake leads to sludges containing as high as 1% phos-
phorus on the VSS basis.
Most investigations, Sawyer (20), Hall and Engelbrecht (22),
Levin and Shapiro (5), were laboratory experiments to study the acti-
vated sludge process parameters effect on the removal of SOP from
sewage. Connell and Vacker (2), Witherow (3), have reported the process
parameter effects based on full scale plant studies which showed good
phosphorus removals. Sawyer (20) found that an addition of glucose to
increase the sewage BOD by UOO mg/L reduced the sewage phosphorus from
2.68 mg/L-P to 0.00 mg/L-P. Sekikawa, et. al. (21), Hall and Engel-
brecht (22), and Levin and Shapiro (5), also observed higher phosphorus
removals when the initial BOD concentration of the substrate was in-
creased. Witherow (3) reported that the phosphorus removal in the
aeration tank was affected by the BOD load applied to the tank and he
observed good phosphorus removals with the influent BOD in the range
of 118 to 202 mg/L. Menar and Jenkins (4) found that the phosphorus
content of the activated sludge volatile solids did not vary signifi-
cantly over a wide range of substrate removal rates and the weighted
average per cent phosphorus on the VSS basis was 2.62%.
The effect of high initial phosphorus content of the sub-
strate on phosphorus removal has been reported by Witherow (3). He
observed good phosphorus removals when the influent phosphorus was in
the range of k.2 to 10.5 mg/L-P. Higher phosphorus levels in the in-
fluent resulted in decreased % phosphorus removals in the activated
sludge process.
The effect of detention time on phosphorus removal has
been reported by Srinath (2U), Alarcon (25), Hall and Engelbrecht (22),
Levin and Shapiro (5), Srinath's (2U) data showed that the phosphorus
and BOD removal rates appear to coincide, approximately 10% removal
after one hour and then gradually increasing to 90% after five addition-
al hours of aeration. Levin and Shapiro (5) observed over 70$
soluble phosphorus removals in an aeration time of 3 hours. Witherow
(3) recommends a modal detention of > 2.5 hours in the aeration tank
for good phosphorus removal. Sekikawa et. al. (21) and Alarcon (25)
found that after all the BOD had been consumed, further aeration of
ML caused the release of phosphorus from the sludge solids due to cell
oxidation (i.e., endogenous respiration).
There are divided opinions on the role of MLSS concent-
ration in the removal of phosphorus in the aeration tanks. Hall and
Englebrecht (22) and Sekikawa, et. al. (21) found MLSS concentrations
had very little effect on the rate or the extent of soluble uptake.
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Srinath, et. al. (2k) reported that maximum phosphorus uptake was
produced by 20 to 30 percent return sludge. Feng (26) observed low
MLSS (500 mg/L) to effect the best phosphorus removals when the aer-
ation rates were high (l8 cu.ft./gallon of ML). Connell and Vacker
(2) obtained maximum phosphorus removal at an average daily BOD loading
rate of about 50 Ibs. of BOD/100 Ibs. of aeration solids. Witherow (3)
observed good phosphorus removals with MLSS >1200 mg/L and loading
rates ranging from 0.26 to 0.35 Ibs. of BOD/lb. of MLSS/day.
Levin and Shapiro (5) found that ML pH had a pronounced
influence on phosphorus removal, a pH range of 7 to 8 was most effec-
tive while pH values >8 and <6 resulted in phosphorus release from the
sludge solids.
Rudolf (17) in 19^7 reported a release of soluble phospho-
rus during anaerobic sludge digestion. In 196l,Alarcon (25) demon-
strated that the soluble phosphorus content of ML decreased during
aeration and increased when aeration was stopped. Campbell (27)
reported that return sludges kept under anaerobic conditions at room
temperature for four hours released phosphorus from the sludge solids
into the liquid. Levin and Shapiro (5), Connell and Vacker (2),
Han and Englebrecht (22), and Witherow (3) indicate that a ML-DO
level of approximately 2 mg/L was necessary for the optimum uptake
of soluble phosphorus. Hall and Engelbrecht (22) and Connell and
Vacker (2) found that the release of phosphorus from the solids
back into the liquid (such as in the final clarifier) was not signi-
ficant if a high dissolved oxygen level had been sustained during
the second half of the aeration period.
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SECTION V
PROCEDURES
MILWAUKEE WASTE WATER TREATMENT FACILITIES AT JONES ISLAND
The wastewater treatment system of the Sewerage Commission
of the City of Milwaukee on Jones Island consists of the East and
West Plant. The capacity of the activated sludge plants is 115 mgd,
and 85 mgd respectively. The physical layout of these plants is
shown in Figure 1. The Milwaukee plants serve a total drainage area
of UlO square miles having a connected population of approximately
1,000,000. Combined sewers serve approximately 6.6% of the total
area and the remainder of the area has a separate sewer system.
The volume of wastewater from this highly industrial area
consists of approximately 22% industrial and 1&% domestic wastewater
(28). The daily average characteristics of screened sewage and some
daily average operation data for 1967, 1968 and 1969 are given in
appendix E. The wastewater flows through mechanically cleaned bar
screens (l inch openings) and then flows through a battery of eight
grit chambers (8 x 8 x 90 feet long each) at a velocity of approxi-
mately one foot per second. Fine screenings are removed by passage
of the degritted sewage through eight rotary drum screens having
3/32 inch slots. Approximately 60 wet tons of screenings and grit
are removed and incinerated daily in a 5 stage multiple hearth
furnace. The screened sewage flow is then divided between the two
activated sludge plants (East and West).
After screening the sewage flows into aeration tanks where
air is supplied through plate diffusers arranged in a ridge and furrow
type pattern. Design detention time is 6 hours. Final sedimentation
in peripheral feed clarifiers is accomplished during a 2 hour design
time for detention. The waste sludge is disposed of by processing
it into Milorganite fertilizer. Further details of the Jones Island
plants can be found in reference 28.
11
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HARBOR
ENTRANCE
LEGEND
•Aw «•«£
Mil UOUO"
Kill** tlUXC-. —.
«»JI( SLUDCf
irruuCNi
rcaiiLUCH -
lEWERAGE COMMISSION
CITY OF MILWAUKEE
JONES ISLAND SEWAGE
TREATMENT PLANT
FIGURE I
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SAMPLING AND ANALYTICAL TECHNIQUES
Sewage sampling - Initially, screened sewage samples were
single grab samples which were used for the hourly study. Aliquots
proportional to flow from these hourly samples were used to make the
2U-hour composite sample.
On 6-13-68, a Phipps - Bird sewage sampler was put into
operation to provide hourly sewage composites (30 - 200 ml. portions/
hour). Aliquots proportional to flow from these hourly composites
were used to make the 2h hour composite. This sampling procedure
markedly reduced the fluctuations in the sewage phosphorus and BOD
concentrations exhibited by the hourly grab samples.
Effluent sampling - Plant effluent samples were hourly
grab samples. The 2h hour composites were prepared the same way as
for sewage. Hourly grab samples of the plant effluent showed very
little fluctuation in BOD and phosphorus concentrations from hour to
hour compared to screened sewage hourly grab samples.
Others - All other samples used in short term studies
were seven liter grab samples.
Analytical methods - Listed below are brief descriptions
of the analytical methods and instrumentations used in this study.
Some of the analytical methods used are described in the appendix
and the instruments manufacturer operation manuals are listed in the
references. Angel Reeves glass fiber filter pads (2.U cm., 93^AH)
were used to provide the filtrates for the analyses of "soluble
components".
Determination of phosphorus - Technicon Autoanalyzer as
described in Appendix A was used. The Autoanalyzer was used only
for SOP analyses because the Technicon acid digestion system, auto-
matic sampler for liquids with colloidal suspended solids and the
automatic filtration system were found to be inadequate.
Dissolved oxygen measurements - were made by a variety
of instruments. The ML-DO was continuously monitored at the outlets
of six EP aeration tanks by means of "galvanic cell" probes. Spot
ML-DO measurements were made by a YSI Model 5^18 probe and Model 51
meter. The YSI Model 5^20 probe and Model 5^ meter were used to
determine the DO levels for the BOD determination. The MLSS-02
uptake rates were determined with a YSI Model 53 Biological Oxygen
Monitor. The procedure used was as described in the suppliers manual
(29) using 1 to 2 and 1 to 5 dilutions on each ML sample.
13
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East Plant effluent turbidity - was continuously monitored
by a Hach CR surface turbidimeter Model 1889. Spot turbidity measure-
ments were made with a Hach Laboratory Turbidimeter Model 2100. The
turbidimeters were operated and calibrated as described in manufactur-
er's "Instruction Manuals" (30) and (31).
The MLSS and RSSS concentrations - were ascertained by a
procedure in use in the Milwaukee Sewerage Commission's Laboratory
(Appendix B).
The total and total soluble cations concentrations (Fe,
Al, Ca and Mg) - were determined on "ternary acid digestates" of the
sample by means of an Atomic Absorption instrument (Instrumentation
Laboratory, Inc. Model No. 153). The instrument operation and cali-
bration were as described in the manufacturer's "Procedure Manual"
(32).
Biochemical oxygen demand (BOD) - the "Azide Modification
of the lodometric method" for the BOD analyses as given in Standard
Methods 12th edition (33) was compared with a modified procedure
using a YSI Model 5^20 probe and Model 51* meter to determine DO levels.
The modified procedure is described in appendix (C). A comparative
study of these methods showed good agreement.
A study to determine a factor for converting U day and
6 day BOD's to 5 day BOD's (l.lU and 0.93) showed good agreement
with those reported by B. L. Goodman & J. W. Foster (31*) of 1.13 &
0.91 respectively for sewage.
14
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SECTION VI
RESEARCH PHASES, RESULTS AMD DISCUSSIONS
CORRELATION OF ACTIVATED SLUDGE PROCESS PARAMETERS TO PHOSPHORUS
REMOVAL ON A PLANT SCALE.
In this study, all pertinent data from the Milwaukee
Severage Commission East Plant located on Jones Island for the 1968
year and for the 1969 year thru September 30 was transferred to IBM
computer cards. The month of January, 1970 was used for the comparison
study of 1968 loge equation.
The data from these cards was then used to establish the
variables included in this analysis. It was initially assumed that the
percent of total phosphorus removed by the activated sludge process is
a linear function of a set of process parameters (note : effluent
soluble orthophosphate was considered as a variable not as a process
parameter). The predictive equation of phosphate removal can then be
expressed as :
Y = ai + a2x2 + a3X3 + a^ + a^ + agxg + a-fXy
a-^ = intercept of the regression line
a^ = regression coefficient for ith parameters,
i = 2, 3, . . .8
where Y = % removal of total phosphate
Xp = food to microorganism ratio (F/M)
F = Ibs. of BOD/day
M = Ibs. of volatile suspended solids (MLVSS)
x^ = detention time (hours) in aeration tank
xjj = cu. ft. of air/gallon of sewage
xc = mixed liquor suspended solids (rag/liter) (MLSS)
xg = dissolved oxygen in the effluent of aeration
tank (mg/liter)
X.T = total phosphate in the influent in Ibs /day (TP_)
microorganisms (M) ( MLVSS )
XQ = soluble orthophosphate in the effluent (mg/liter)
15
-------
Another set of statistical evaluations was made on the
basis of the assumption that the distribution of parameters influenc-
ing percent removal of total phosphate (x2, x^, ... XQ) is exponential,
such that the logarithm of the dependent variable (percent removal of
total phosphate) varies linearly with the logarithm of the independent
variables. The regression equation for this assumption can be ex-
pressed as
a3
Y =
The data was analyzed in the following groups with several
trials in each group.
1968 Data - Natural Form (362 cards)
1969 Data - Natural Form (273 cards) 1/1/69 - 9/30/69
1968 + 1969 Data - Natural Form (601 cards)
1969 excluding brewery strike period -
Natural Form (217 cards)
1968 Data - Logarithmic Form (3^2 cards)
1968 Data - Logarithmic Form (231* cards)
1969 jjata - Logarithmic Form (259 cards)
1968 + 1969 Data - Logarithmic Form (601 cards)
1969 excluding brewery strike period -
Logarithmic Form (217 cards)
During 1969, a brewery strike from June 9 to July 15
caused significant differences to occur at the sewage treatment plant.
Thus , the 19&9 data was analyzed including and excluding the strike
period to determine the effect of large volumes of brewery wastes
on the Milwaukee treatment plant .
Method of analysis - A multiple regression analysis was
performed with the data from 1968 and 1969 in both the natural form
and in the logrithmic form (log to the base e) and is explained
completely in a separate report (35).
Results - Several equations were developed for each set
of data both in natural form and in logarithmic form. Generally the
significant variables were:
Xp F/M ratio
Xo Detention Time
XEJ Mixed Liquor Suspended Solids
X TP/M ratio
16
-------
As an example, the best equation developed for the 1968
data was the following. Equation Number 1
Loge Y = 3.55118 - 0.02855 Loge xg + 0.05819 Loge x
- 0.10076 Loge X
This equation used data from those days (23^) in 1968
when the effect of overloaded clarifiers was not evident. This was
determined "by using the following criteria:
1. Effluent BOD < 20 mg/1
2. Effluent SS < 20 mg/1
3. Clarifier Blanket < 1^'
k. 80/5, the calculated % removal was within 10$ except
for 3 days.
17
-------
A conclusion can be drawn from this analysis. When the
removal of phosphorus exceeds 80$ in the Jones Island plant, the
significant parameters are Food/Microorganism ratio, mixed liquor
suspended solids and Total Phosphorus/Microorganism ratio as
related in Equation (l).
18
-------
DEMONSTRATION OF CYCLIC REMOVAL OF PHOSPHORUS FROM SEWAGE BY AN
ACTIVATED SLUDGE PLANT.
In the literature prior to 1966, the majority of the studies
reported on phosphorus removal from sewage by the activated sludge
process were small scale laboratory experiments under ideal conditions.
A few plant scale investigations were reported but were limited to the
study of SOP levels in the effluent from the aeration tanks and not in
the effluent from the secondary clarifier. Very little information
from long term studies was available on an activated sludge plant's
capability to remove total and soluble phosphorus from sewage on a hour-
ly basis. At the outset of this investigation, the influent and the
effluent of a 115 mgd activated sludge plant were monitored on an hour-
ly basis, 7 days a week. This initial approach was taken to study the
effects of plant operation practices, sewage flow and composition on
the hourly removal of sewage phosphorus by an activated sludge plant.
This study was carrried over a period from 12-3-67 to 12-19-68.
Screened sewage and East Plant effluent grab samples were
taken every hour and stored under refrigeration. These samples were
analyzed the next day for BOD, TP and SOP. The data from the hourly
grab samples of screened sewage exhibited extreme fluctuations, where-
as the data from the effluent hourly grab samples showed very little
fluctuation. Data for each hour for each day of the week was aver-
aged because the data showed that sewage total phosphorus removal
was influenced by the sewage composition and volume of flow, and by
operation of the clarifiers which varied from day to day. For
example, on Sunday and Saturday sewage volume of flow, BOD and
phosphorus concentration were consistently lower than those for
Monday thru Friday. The data for Monday thru Friday was considered
separately because insufficient capacity in the dewatering facilities
on those days controlled the MLSS level and the clarifier blanket
depths. Because of this, it was usually not possible to maintain a
given MLSS level in the aeration tanks from day to day during this
study.
The averaged hourly data for the screened sewage and for
the East Plant effluent are presented in Figure 2. The East Plant
effluent data was adjusted by 9 hours to compensate for the plant
flow thru time. After this adjustment, the effluent data correspond-
ed fairly close to the influent data.
Figure 2 exhibits the cyclic nature of phosphorus re-
moval by the East Plant. It also demonstrates that three cycles
occur during each week in the East Plant. These cycles are related
to three sets of circumstances which occur weekly and may vary from
week to week.
19
-------
400
360
320
280
-1240
—
2 200
160
Q
O 120
O
80
40
0
LEGEND
SEWAGE
EFFLUENT
FLO*
_\ J
\ .1
I \
/ V./
I40
ISO
120
no
IOO
90
60
50
/ V
\ /
\ '
V
Z 6
Q. 4
t-
2
0
/ \
\ /
\ /
MNMNMNMNMNMNMN M
SUNDAYS MONDAYS TUESDAYS WEDNESDAY THURSDAY FRIDAYS SATURDAYS
FIGURE 2 SEWAGE 8 EFFLUENT AVERAGE HOURLY COMPOSITION I2/3/67 TO 6/I5/68 (EFFLUENT ADJUSTED FOR 9 HOUR DETENTION)
-------
The first cycle was labeled the "Sunday Cycle". It
started at approximately U PM (see Figure 2) on Saturday (actual
effluent time would be 1 to 2 AM Sunday) and continued until 6 AM
Monday (actual effluent time, 3 to 1» PM Monday.). The reduced sewage
flow and BOD concentrations occurring during this cycle resulted in
increased detention time and air application rate which in turn in-
creased the ML-DO. The most striking characteristic of the Sunday
Cycle was the consistency of the low levels of TP, SOP and BOD in the
East Plant effluent from hour to hour, which averaged below 1.0 mg/L-P,
0.5 mg/L-P and 10 mg/L respectively. This period appeared to have the
most favorable conditions for the activated sludge process to remove
phosphorus from sewage.
The second cycle was called the "Daily Cycle". It differed
from the first in that the effluent TP, SOP and BOD levels fluctuated
over a 2k hour period in the same manner as the sewage flow and
nutrient (phosphates) concentrations. This cycle started with peak
flow and BOD levels at 2 to 3 PM on any day and gradually decreasing
to the lowest values at about 3 AM. The daily cycle occurred Monday
thru Friday as shown in Figure 2.
The third cycle was the "Weekly Cycle". The main charac-
teristics of this cycle were the increase in the amount of insoluble
phosphorus and BOD in the plant effluent starting from Monday which
kept on increasing as the week progressed. This cycle was found to
be dependent on the mixed liquor settleability and the capacity of
the dewatering facilities for removing the waste sludge. Most of the
time dewatering facilities were unable to remove the waste sludge as
fast as it was produced. As a result, the unremoved waste sludge
accumulated in the clarifiers causing higher sludge blankets during
hours of peak flow on certain days. The amount of waste sludge
accumulated in the system generally increased from Monday to Saturday,
resulting in high sludge blankets during the peak flow hours. The
final result was that the overloaded clarifiers sometimes discharged
MLSS over the weir during peak flow hours and caused an increase in
the effluent BOD and insoluble phosphorus concentration as shown in
Figure 2.
The effect of clarifier sludge blanket depths on the TP,
SOP and SS concentrations of the East Plant effluent are summarized
in Table 1 on the next page.
21
-------
TABLE 1
EFFECT OF CLARIFIER SLUDGE BLANKET DEPTHS ON EP EFFLUENT QUALITY
Maximum Clarifier Daily Averages from Hourly
Blanket Depth Effluent Sample Data
Reached in 2U Hours 12/3/67 to 9/15/68
Feet
0 to U
5 to 8
9 to 13.5
TP
mg/L-P
1.11
l.OU
2.10
SOP
mg/L-P
0.70
0.6U
0.88
Insoluble -P(
mg/L-P
O.Ul
O.UO
1.22
» SS
mg/L
16
1U
1*5
Number
of Days
Observed
107
75
102
* Insoluble P = TP - SOP
The above data shows that the effluent SOP levels on the
average did not change greatly with increasing sludge blanket depths,
22
-------
PLANT STUDY OF THE EFFECT OF CLARIFIER BLANKET DEPTHS ON CLARIFIER
EFFLUENT SOP RESIDUAL
It is well known that SOP is released by sludge solids when
they are detained in the final clarifiers for extended periods of time.
Thus, the release of SOP from the clarifier sludge solids could in-
crease the clarifier effluent SOP concentration. If this occurred^the
effects of the process parameters in removing SOP by MLSS during
aeration would be obscured.
The effect of sludge detention time on the release of SOP
from sludge solids was first studied in the laboratory. A typical
laboratory experiment consisted of using a ML sample which had been
taken from an aeration tank after six hours of aeration ( .and contained
0.3 mg/L - P of SOP). This ML sample was then divided into five
portions which were placed into five one liter graduate cylinders and
allowed to settle at room temperature (72°F). Then at hourly intervals
(from one cylinder each hour) the supernatant was carefully removed in
200 ml aliquots (four in all). The supernatant fractions and the
sludge fraction were then analyzed for SOP. The SOP release and dif-
fusion data are presented in Figure 3. This experiment showed that the
amount of SOP released from the sludge solids increased with increased
sludge detention time as expected. However, as shown in figure 3, the
majority of the released SOP remained in the quiescent sludge blanket
fraction and only a small amount of released SOP diffused into the
supernatant with time. This means that the clarifier effluent can
contain some SOP released by the sludge solids detained in the
clarifier by the process of diffusion. But, more important are
clarifier operations during periods of high blanket and peak flows.
The data indicates that it is possible that if the inflow ML causes
turbulent conditions during periods of high blankets the clarifier
effluent could contain SOP released by the solids detained in the
clarifiers.
Plant studies to determine if clarifier sludge SOP release
had a significant influence on the clarifier effluent SOP residual
were also made. During a ten day period the ML effluent from an
aeration tank (EP Tank #10), the ML influent to clarifier #5 and the
final effluent from a clarifier (EP Clarifier #5) were sampled 5
times a day. The SOP content was determined on each sample.
The data in Table 2 showed that during this study period
there was very little diffusion of SOP from the clarifier sludge
blankets to the clarifier effluent.
23
-------
Q.
I
_l
\
O
Q.
O
30
20
10
g
i-
o
<
a:
CM
o
<
cc
S o
en
o
<
-------
TABLE 2
COMPARISON OF SOP CONCENTRATION (MG/L-P)
OF AERATION TANK-10 OUTLET ML, CLARIFIER #5 ML-FEED,
CLARIFIER #5 EFFLUENT IN RELATION TO CLARIFIER BLANKET DEPTH
SAMPLING TIME
12-23
1968
12-21*
12-26
12-27
12-30
12-31
1-3
1969
1-U
1-6
1-7
Outlet
Feed
Effluent
Blanket Depth
Outlet
Feed
Effluent
Blanket Depth
Outlet
Feed
Effluent
Blanket Depth
Outlet
Feed
Effluent
Blanket Depth
Outlet
Feed
Effluent
Blanket Depth
Outlet
Feed
Effluent
Blanket Depth
Outlet
Feed
Effluent
Blanket Depth
Outlet
Feed
Effluent
Blanket Depth
Outlet
Feed
Effluent
Blanket Depth
Outlet
Feed
Effluent
Blanket Depth
7:30 AM
0.1*1*
-
0.05
6
0.07
0.03
0.22
6
0.19
0.21
0.28
1*
0.12
0.3l»
0.37
6
0.67
0.77
0.76
1
0.1*2
0.66
0.63
1
1.1*
1.1*
1.1*
1
1.0
0.92
1.5
1
3.1
3.2
2.9
1
3.7
J».o
3.7
1
9:30 AM
-
0.03
6
0.19
0.06
0.13
6
0.20
0.19
0.27
1*
0.06
0.19
0.2l*
6
o.6l
0.57
0.6U
1
0.13
O.ll*
0.37
1
1.3
1.3
1.1*
1
0.27
0.2U
0.70
1
3.0
3.0
3.0
1
2.9
2.7
2.7
2
11:30 AM
0.05
0.02
0.03
7
O.OU
o.oi*
0.07
6
0.26
0.22
0.29
1*
0.06
0.08
0.13
6
0.1*2
0.1*1
0.1.6
1
0.15
0.13
0.19
1
1.1
1.1
1.0
1
0.12
0.06
0.16
1
3.0
2.9
2.9
1
2.0
1.8
1.7
2
1:30 PM
0.06
0.03
o.oi*
8
o.oi*
0.02
_
6
0.35
0.36
0.31*
1*
0.05
0.05
0.07
1*
0.32
0.27
0.31
1
0.07
0.11
-
1
0.88
0.71*
1.0
1
o.oi*
0.06
0.09
1
2.7
2.7
2.6
1
1.6
1.2
1.3
3
3:00 PM
0.05
0.01
_
8
_
-
_
6
0.36
0.31
_
U
o.oi*
0.06
_
1*
0.39
0.35
-
1
-
-
-
1
0.83
0.71*
-
1
o.oi*
0.07
-
1
2.7
2.6
-
1
1.6
1.3
_
1*
Blanket nepth - Feet
25
-------
PLANT LOADING STUDY (F/M AND TP/M)
The first year's data indicated that the plant loading
parameters, food to microorganism ratio (F/M) and total phosphorus
to microorganism ratio (TP/M), appeared to be related to the removal
of phosphorus by the activated sludge process. The effects of the
F/M and TP/M loadings were studied simultaneously in both the acti-
vated sludge plants. The following loadings were chosen for this
study:
Plant Loading Ratios Remarks
F/M TP/M
East (EP) 0.300 0.012 Optimal Loading
West (WP) 0.600 0.021* High Loading
Under these loadings the EP was expected to yield good phosphorus
removals as compared to the WP. It was further planned to reverse
the above loadings between the two plants to see if the reverse
results could be observed. The desired F/M and TP/M loadings were
obtained by modifying the operations of both plants.
The pertinent data summarized in Table 3 are averages of
the daily data for the periods indicated. In general, the data
indicated that the high loadings (with average values of 0.511* F/M
and 0.019 TP/M in the WP for period II) reduced the WP-SOP removal
efficiency. The effect of the plant loadings on the daily EP and
WP effluent SOP concentrations are shown in Figure U.
The initial plan was to then reverse the plant loadings
to see if the EP - SOP removal efficiency would be reduced. A
viscous floating material appeared on the surface of the EP aeration
tanks in period II but none was observed in the WP. The amount of
this viscous material continued to increase in the EP until it was
felt that this material and the continuation of the loading study
would jeopardize the EP treatment efficiency. Regular def earning
agents were ineffective in. breaking this foam. Vacuum skimming
of the EP aeration tanks and clarifier feed channels reduced the
amount of this foam and aided in overcoming this problem. Thus,
the plant loadings were not reversed and this study was suspended.
The sewage flow distribution and other process parameters were then
changed in both plants and were gradually restored to their normal
values in period III. Further details on this foam problem are
given in appendix (D).
26
-------
ro
-j
TABLE 3
AVERAGES OF DAILY DATA BY PERIODS
Period
Plant
% Sewage Distribution
% Return Sludge
I -
Prior to Study
Period
2/1 to 2/16-
Drv Flov
East
58
25
West
1*2
25
II -
East
50
35
Loading Study
Period
2/17 to 3/10-
Dry Flow
West
50
25
III -
East
5U
25
After the Study
Period
3/11 to 3/18-
Dry flov
West
1*6
25
IV -
3/19
East
5U
25
Period of
Excessive
Rainfall
to 3/31-Rain
West
146
25
Air - Million cu.ft./day 133
107
133
107
133
107
118 107
SEWAGE
SOP
TSP
TP
BOD
SS
FLOW
EFFLUENT
SOP
TSP
TP
BOD
SS
MG/L-P
MG/L-P
MG/L-P
MG/L
MG/L
MGD
MG/L-P
MG/L-P
MG/L-P
MG/L
MG/L
2.5
U.T
9.8
258
218
100.1
1.5
1.9
2.2
15.8
18
69.1
1.7
2.2
2.1*
15.8
19
2.7
1*.2
9.7
260
253
88.1
1.1
l.Ji
1.9
17.0
23
86.1
1.8
2.1
2.9
21.0
26
2.5
i*.o
9.9
306
258
93.0
0.59
0.9l»
1.3
19.6
21
77.0
1.8
2.2
2.6
22.2
26
2.0
3.2
8.5
2l*7
232
102.2
0.28
0.1*1*
0.82
18.8
18
86.1
0.77
0.97
1.5
20.5
28
PROCESS PARAMETERS
F/M
TP/M
MLSS MG/L
DO MG/L
DETENTION HRS
AIR CU.FT./GAL
% REMOVAL
SOP
TSP
TP
0.1*36
0.0167
2l*6l
U.3
7.3
1.3U
0.372
0.01U2
2513
7.5
1.57
0.291
0.0109
2953
3.1
7.9
1.53
0.511*
0.0188
2273
6.2
1.26
0.366
0.0319
2989
3.9
7.7
l.M*
O.J»72
0.0152
2657
6.9
1.1*0
0.320
0.0109
305»»
3.1
7.1
1.18
0.335
0.0118
3291*
6.2
1.26
1*0.0
59.6
77.6
32.0
53.2
75.5
59.3
66.7
80.1*
33.3
50.0
70.1
76.U
76.5
86.9
28.0
1*5.0
73.7
86.0
86.3
90.U
61.5
69.7
82.1*
-------
S3
00
PRIOR TO STUDY PERIOD
2/1/69 TO 2/16/69
LOADING STUDY PERIOD
2/17/69 TO 3/10/69
AFTER THE
STUDY PERIOD
3/11/69 TO 3/18/69
PERIOD OF CONTINUOUS
RAINFALL
3/19/69 TO 3/31/69
LEGEND
EAST PLANT
WEST PLANT
SEWAGE
Su
3/23
Su
3/30
FIGURE 4 EFFECT OF PLANT LOADINGS ON PLANT EFFLUENT SOP LEVEL
-------
Reduced TP/M and F/M loadings observed in period IV were
caused by surface runoff due to continuous rainfall in this period
(1.02 inches in 13 days) which affected influent composition and flow
volumes. The reduced loadings frequently happen because of infil-
tration, since approximately 6,6% of the Commission's service
area is served by combined sewers. Throughout this three year study,
improved SOP removals in both plants were usually observed during
such periods of continuous rainfall similar to the data shown in
period IV.
29
-------
EFFECT OF BREWERY WASTE LOAD
The effect of the industrial wastevater from the "brewery in-
dustries in Milwaukee on the activated sludge plants operations were
studied in 1969 when they were shut down due to a strike lasting from
June 9 to July 15. The loss of the brewery industrial wastewater and
the changes in sewage treatment plant operations made to offset the
effects of this loss offered an excellent opportunity for another plant
scale loading study (F/M and TP/M) in the East and West plants.
One of the significant effects of this industrial waste loss
was a substantial reduction in the average sewage BOD when compared to
the periods prior to and after the shutdown period as shown in Table U.
The data indicated that the Milwaukee breweries average BOD contri-
bution comprised approximately 22% of the normal total BOD load. The
BOD removal efficiencies for both plants vere not affected; however,
they continued to exhibit greater than 90$ BOD removals.
It was also observed in a previous breweries shutdown in
1953 that the sewage BOD was substantially lower. During this previous
period of low BOD the Milorganite nitrogen content decreased to an
average of 5.31$ from a normal value of 6.0%. During the 1969 shut-
down, the plant operations were modified to reduce nitrification by
decreasing the MLSS level, decreasing the detention time and decreas-
ing the air applied in both plants. These plant operational changes
were successful during the 1969 brewery shutdown, as evidenced by the
small decrease in the average Milorganite nitrogen content, 5.75$ N
va normal of 6.0$ N.
During the 1969 strike period however, the TP removal effi-
ciencies for both plants dropped from a monthly average of 85$ to 63$.
This decrease in TP removal efficiency was due to a significant
reduction in the SOP removal efficiency from a monthly average of 80$
to an average of 12.5$ and 0.2$ in the East and West plants respect-
ively as shown in Table U. The decreased SOP removal was apparently
influenced by an increase in F/M, an increase in TP/M and a decrease
in the MLSS levels, these are shown in Tables U and 5. After the
breweries resumed their normal production and the sewage treatment
plant returned to their normal operating parameters, the SOP removal
efficiency for both plants improved tremendously.
During this long period of continuously poor removal of
soluble phosphorus from sewage, one could expect to observe the RSSS
phosphorus content to decrease. In Figure 5 are plotted the nitrogen
and phosphorus contents of RS based on VSS (from the weekly composites
for EP and WP return sludges). The data in Figure 5 shows that the
RSVSS phosphorus did not decrease during this period of poor soluble
phosphorus removal. Therefore, it may be assumed that a portion of
30
-------
TABLE U
SUMMARY PERIOD AVERAGES
Period
April, 1969 May, 1969 Breweries Shutdown August, 1969
June 9th - July 15th
u>
Plant
% Sewage
% Return
SEWAGE
SOP
TSP
TP
BOD
SS
FLOW
EFFLUENT
SOP
TSP
TP
BOD
S3
Distribution
Sludge
MG/L-P
MG/L-P
MG/L-P
MG/L
MG/L
MOD
MG/L-P
MG/L-P
MG/L-P
MG/L
MG/L
East
56
21,
2.1
3.3
7.8
230
210
109.1*
0.31
0.51*
0.70
9.9
11
West
UU
26
85.0
0.32
0.51*
0.96
13.2
18
East
60
23
2.0
3.1
7.7
238
238
112.1
0.27
O.U8
0.79
17.5
19
West
UO
27
7l».9
0.26
O.U7
0.90
15.2
31
East
58
22
2.1
3.6
7.1
182
196
110.9
1.9
2.1
2.U
10.5
12.6
West
U2
26
79.9
2.1
2.3
2.7
12.0
16.5
East
59
2U
2.3
2.8
7.3
221
218
115.6
0.50
0.60
0.93
9.U
15
West
Ul
26
81.5
O.Ul
0.53
1.2
12.9
28
PROCESS PARAMETER
F/M
TP/M
MLSS MG/L
DO MG/L
DETENTION HOURS
AIR CU.FT./GAL
% REMOVAL
SOP
TSP
TP
0.352
0.012
2880
3.2
6.7
1.08
0.366
0.012
2970
6.3
1.2U
0.38U
0.012
2700
1.7
6.5
1.10
0.350
0.011
2770
6.9
1.32
0.1*76
0.019
1850
3.6
6.2
0.99
0.529
0.021
1870
5.3
1.10
O.U35
O.Oll*
2390
U.9
6.1
1.09
0.389
0.013
2590
6.2
1.25
86
8U
91
8U
83
87
87
85
90
87
85
88
12.5
UO
65
0.2
35
62
79
80
87
81
82
8U
-------
TABLE 5
COMPARISON OF PERIOD AVERAGES:
LOADING STUDY VS. BREWERIES SHUTDOWN
Period
1969
Plant
% Sewage Distribution
% Return Sludge
SEWAGE
SOP MG/L-P
TSP MG/L-P
TP MG/L-P
BOD MG/L
SS MG/L
FLOW MGD
EFFLUENT
SOP MG/L-P
TSP MG/L-P
TP MG/L-P
BOD MG/L
SS MG/L
PROCESS PARAMETER
F/M
TP/M
MLSS MG/L
DO MG/L
DETENTION HRS.
AIR CU.FT./GAL
% REMOVAL
SOP
TSP
TP
Loading
Study
Feb. 17th - Mar. 10th
East
50
35
2.7
U.2
9.7
260
253
88.1
1.1
1.1*
1.9
17.0
23
0.291
0.011
2950
3.1
7.9
1.53
59
67
80
West
50
25
86.1
1.8
2.1
2.9
21.0
26
0.511*
0.019
2270
6.2
1.26
33
50
70
Breweries Shutdown
June 9th - July 15th
East
58
22
2.1
3.6
7.1
182
196
110.9
1.9
2.1
2.U
10.5
12.6
12.5
1*0
65
West
1*2
26
79.9
2.1
2.3
2.7
12.0
16.5
0.1*76
0.019
1850
3.6
6.2
0.99
0.529
0.021
1870
5.3
1.10
0.2
35
62
32
-------
U)
OPERATION
IN OPERATION
NITROGEN BASED ON RSVSS
% PHOSPHORUS BASED ON RSVSS
2.0
4/13 4/20 4/27 5/4 5/11 5/18 5/25 6/1 6/8 6/15 6/22 6/29 7/6 7/13 7/20 7/27 8/3 8/10 8/17
FIGURE 5 EFFECT OF BREWERIES SHUTDOWN ON R S COMPOSITION
(WEEKLY COMPOSITES)
-------
the sewage insoluble phosphorus was made available for assimilation
by the microorganisms either in the initial aeration period with MLSS
or in the subsequent recycling with the RS.
In the Milwaukee waste treatment plants the solids synthe-
sized from the sewage BOD, suspended solids, and phosphorus are
continuously removed from the system as Milorganite. During the
breweries shutdown Milorganite production dropped significantly as
shown in Table 6. Weekly balances are presented because it was
difficult to calculate a reliable estimate for solids detention or
withdrawal from the two plants on a day to day basis. The weekly
pounds applied of sewage BOD and VSS also declined for the same
period as shown in Table 6. The Milorganite phosphorus content did
not appear to change significantly before, during, or after the
shutdown as shown in Table 6. Phosphorus balance data showed that,
on a weekly basis, the phosphorus removed from sewage was recovered
in the waste solids withdrawn from the system as Milorganite* It
appears that the reduction in phosphorus removal observed during
the breweries shutdown was due to insufficient synthesis of solids
for the quantity of phosphorus present in the sewage. In the
Milwaukee plants the amount (and/or efficiency) of phosphorus
removed from sewage appears to be influenced more by the amount of
solids produced in the activated sludge process than by the
activated sludge process parameters studied. In addition, it
appears that the brewery waste water aids soluble phosphorus re-
moval at the Milwaukee plants.
34
-------
TABLE 6 RELATION OF PHOSPHORUS REMOVED TO SOLIDS SYNTHESIS
(1969 WEEKLY DATA)
SOLIDS PRODUCED (DRY BASIS)*
WEEK
OF
3-30 to
l*-6 "
U-13 "
1»-20 "
U-27 "
5-1* "
5-11 "
5-18 "
5-25 "
6-1 "
6-8 "
6-15 "
6-22 "
6-29 "
7-6 "
7-13 "
7-20 "
7-27 "
8-3 "
8-10 "
8-17 "
8-21* »
U-5
U-12
U-19
i*-26
5-3
5-10
5-17
5-2U
5-31
6-7
6-1U
6-21
6-28
7-5
7-12
7-19
7-26
8-2
8-9
8-16
8-23
8-30
TONS
WEEK
1376
1682
1650
183>*
1655
1537
131*8
1656
16UO
lll*8»*
15U7***
1309
1076
81*1
1026
1171
1UU7
11*1*6
1509
1678
15^5
15l<9
% P
TONS
PHOSPHORUS
2.25
2.26
2.27
2.18
2.23
2.30
2.3»*
2.28
2.30
2.35
2.57
2.59
2.38
2.19
2.30
2.30
2.17
2.33
2.1*3
2.51*
2.53
2.63
31.0
38.1
37.5
1*0.0
36.9
35. U
31.5
37.8
37.7
27.0
39.8
33.9
25.6
18.1*
23.6
26.9
31. f*
33.7
36.7
1*2.6
39.1
1*0.7
TONS APPLIED/WEEK
(BOTH
PLANTS) BREWERIES
PHOSPHORUS BOD
1*1*. 8
1*7.0
1*1.3
1.1*. 8
1*2.8
1*2.5
1*1*. 5
1*2.1*
UO.U
1»1.3
U3.7
1*1*. 0
37.6
30.5
37.9
39.3
_
35.1
1*0.1*
1*1*. 8
1*1*. 3
1*1.9
1292
11*51
1061*
ll»07
1358
1335
131*9
1218
1298
1189
1098
1139
1011*
829
957
1013
1251
1260
1167
1389
1190
11*23
VSS OPERATION
ll*ll
ll»91
1293
131*6 IN
1321* OPERATION
11*56
1503
903
963
91*2
917
960
8U8 SHUTDOWN
659
775
772
91*8
937
551* IN
1093 OPERATION
1053
1091
NOTE *Milorganite production adjusted to account for either solids detention or
withdrawal from the system.
**Abnormally low Milorganite production due to a holiday and the dewatering
facilities shut down for two and a half days.
***High Milorganite production because the MLSS levels in the system were
reduced from a weekly average of 2800 mg/L to the low level of
2000 mg/L (* 1*00) for the East Plant.
-------
PLANT SCALE PHOSPHORUS BALANCES
The phosphorus balances shown in Table 7 were made to check
the accuracy of phosphorus and plant flow data obtained in this project.
The influent and effluent TP contents were determined by a Ternary Acid
Digestion procedure (as described in Appendix A). The Milorganite
phosphorus content was determined by the gravimetric AOAC Quinoline
Molybdate Method 2.023 and 2.02U (36).
Phosphorus recovered in the Milorganite was compared with that
removed from the influent by the two plants. The initial phosphorus
balance calculations were made with the daily data but it was found too
difficult to accurately account for phosphorus associated with the solids
in the system. The phosphorus balances using weekly phosphorus removals,
plant flows» and Milorganite production data were considered more real-
istic. The estimated solids storage in the system on a weekly basis
usually exhibited less fluctuation than on a daily basis.
An average of 95.7$ of the phosphorus removed by both plants
could be accounted for in the Milorganite produced over the 37 week
period. As evidenced by the weekly phosphorus balances as shown in
the Table 7, plant phosphorus and flow data were reasonably accurate.
The phosphorus balances for both plants established the
high phosphorus removals by the Milwaukee Sewage treatment plants and
demonstrated that the phosphorus was removed from the process as
Milorganite produced from waste sludge.
-------
TABLE 7
CALCULATED WEEKLY PHOSPHORUS RECOVERIES
#TP Removed/Week in 1969
Weekly
Period
Feb.
Mar.
Apr.
May
June
July
Aug.
Sept
Oct.
Nov.
10-16
17-23
2U-2
3-9
10-16
17-23
2U-30
31-6
7-13
ll*-20
21-27
28-1*
5-11
12-18
19-25
26-1
2-8
9-15
16-22
23-29
30-6
7-13
lU-20
21-27
27-2
3-9
10-16
17-23
2U-30
31-6
. 7-13
lU-20
21-27
28-U
5-11
12-18
19-25
26-1
2-8
9-15
16-22
23-29
WP
29,81*0
38,559
37,355
32,113
32,911*
28,571*
31*. 805
31*. 851
33,960
36,021*
30,261
33,297
30,331*
29,696
31,257
29,851
22,135
36,266
21*, 819
18,120
17,325
16,11*2
21,1*71*
_
21,762
29,779
31*, 007
30,575
23,81*5
17,906
2l*,l*21
22,690
26,993
9,1*79
10,551*
30,682
37,657
30,508
33,277
31*, 707
35,758
28,857
EP
1*0,026
32,206
1*9,009
37,828
1*1,058
1*5,337
1*1*. 857
1*1»,903
1*1*. 1*52
1*6,81*1
1*5,568
1*6,195
1*3,771
1*5,568
1*5,971*
1*6,1*22
38,708
1*9,028
1*1,953
30,653
22,268
21,1*67
31,392
-
3l*, 216
1*0,796
1*5,022
1*8,187
1*3,1*96
29,777
1*3,529
37,858
1*2,01*1
1*6,953
38,166
1*6,181
59,887
1*1*. 977
1*9,807
1*9,251
1*8,1.12
1*1,398
Both
Plants
69,866
70,765
86,361*
69,9»*1
73,972
73,911
79,662
79,751*
78,1*12
82,865
75,829
79,1*92
7»*, 105
75,261*
77,231
76,273
60,81*3
85,291*
66,772
1*8,773
39,593
37,609
52,866
_
55,978
70,075
79,029
78,762
67,31*1
1*7,683
67,950
60,51*8
69,031*
56,1*32
1*8,720
76,863
97,51*1*
75,1*85
83,081*
83,958
81*, 170
70,255
MilorRanite
69,388
69,056
72,338
66,709
66,1*39
69,572
67,910
65,582
7l,6lO
78,71*1*
71*, 802
70,800
69,986
68,1*59
69,51*1*
77,982
1*8,1*1*5
86,939
72,105
52,837
1*0,795
36,681
1*6,336
_
63,760
69,291*
71*. 771
75,871*
71*. 090
51,729
61*. 1*97
57,753
6U, 691
58,232
56,726
6U, 1*00
70,896
67,691
78,371
76,175
71,562
6U, 377
% (*)
Phosphorus
Recovery
99.3
97.6
83.8
95.1*
89.8
9'*.1
85.2
82.2
91.3
95.0
98.6
89.1
91*. I*
91.0
90.0
102.2
79.6
101.9
108.0
108.3
103.0
97.5
87.6
_
113.9
98.9
91*. 6
96.3
110.0
108.1*
91*. 9
95.»»
93.7
103.2
116.1*
83.8
72.7
89.7
91*. 3
90.7
85.0
91.6
Average % Recovery
95.7
(*) ^Recovery
(#TP removed in Milorganite-J-#TP removed in
the plant) X 100
37
-------
RELATIONSHIP BETWEEN TOTAL BOD REMOVAL AND TSP REMOVAL IN AN
ACTIVATED SLUDGE PLANT (BODR/TSPR)
Sawyer (20) studied the removal of BOD in conjunction
with soluble phosphorus removal by the activated sludge process.
He demonstrated in the laboratory, that by adding additional BOD
(as glucose) he could obtain increased soluble phosphorus removal.
From this work he concluded that 100 pounds of BOD were removed for
each pound of soluble phosphorus in the activated sludge process.
Hall and Engelbrecht (22) concluded from their studies that 80 to
110 pounds of COD were removed per pound of soluble phosphorus.
It was decided to determine how applicable this concept was on a
plant scale.
The BOD to TSP removal ratios (i.e., BODR/TSPR) for
both plants were calculated from the daily 2U hour sewage and
effluents composites data. The calculated removal ratios from
2/9/69 to 11/30/69 are presented as frequency diagrams in Figures
number 6 and 7. The data used in these diagrams are for periods
of normal operating conditions.
The magnitude of the BODR/TSPR ratio appears to be
dependent on the day of the week as shown in Table 8.
TABLE 8
Average BODp/TSPR Ratios
Plant Weekdays Weekend Days
Monday thru Friday
West Plant 86
East Plant 90
The data appears to indicate that in the Milwaukee activated
sludge plants the removal of soluble phosphorus from sewage is
not dependent on the removal of total BOD as we always observed
greater than 90/J BOD removals.
38
-------
UJ
vO
24
20
16
12
UJ 8
O
z
UJ 4
cr
cr
3 °
o
°36
u.
0 32
>- 28
O
^ 24
O
£20
16
12
8
WEST PLANT DATA
AVERAGE 86LBS BOOR/LB TSPR
EAST PLANT DATA
I
-AVERAGE 90LBS BODR/LB TSPR
r
J
•f-
-I-
-H
-f-
-t-
•4-
-I-
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200
9 19 29 39 49 59 69 79 89 99 109 119 129 139 149 159 169 179 189 199 209
POUNDS BOD REMOVED/POUND TSP REMOVED
FIGURE 6 FREQUENCY DISTRIBUTION BODR/TSPR WEEKDAY DATA
-------
UJ
o
6 -
4
2
oc
So-
o
o
o
U. 8
O
S 2
tr
SATURDAYS
WEST PLANT
I
c
VERAGE 6C
1
EAST PLANT
-AVERAGE 64
SUNDAYS
WEST PLANT
AVERAGE 44
EAST PLANT
-AVERAGE 50
i
0 10 20 30 40 50 60 70 80 90 100 110 120 130
9 19 29 39 49 59 69 79 89 99 109 119 129 139
POUNDS BOD REMOVED/POUND TSP REMOVED
FREQUENCY DISTRIBUTION BODR/TSPR WEEKEND DATA
FIGURE 7
40
-------
STUDY OF SOLUBLE PHOSPHORUS UPTAKE IN EAST PLANT AERATION TANKS
(GENERAL)
Eight separate studies were made during the course of two
years on soluble phosphorus uptake in the aeration tanks. The ML de-
tention time and air application rates were kept fairly constant at 6
hours and 3300 to 3500 cfm respectively. No attempt was made to control
the MLSS levels and the F/M and TP/M loadings. Thus, they were the
varying parameters which affected the ML-DO level and phosphorus re-
moval efficiencies.
ML Spot samples (over a six hour period) were taken at
each hour along the aeration tank and brought immediately to the labora-
tory and filtered. At the location from which the ML samples were taken
the ML-DO was also measured. The ML filtrates were analyzed for SOP
and/or TSP, soluble BOD, and pH. The SS were also determined on the ML
samples. In addition, the zero hour detention grab samples of screened
sewage and RS samples were analyzed for SOP or TSP.
The data from the majority of these studies were incon-
clusive because the studies were conducted on influent arriving at 8
to 9 AM when the influent BOD, TP and SOP concentrations were near
their lowest average concentration in the twenty four hour period
(see Figure 2). As a result, practically no dramatic differences in
effluent residual SOP were observed which could be related to the pro-
cess parameters under investigation.
It was consistently observed in these studies, that the
SOP concentration of ML resulting from the mixing of screened sewage
and RS in the mixing and ML feed channel as well as at zero hour
aeration time in the aeration tanks was usually 2 to 3 times greater
than the expected calculated SOP concentration in a corresponding
mixture of sewage and RS. Also, at times the concentration of ML-SOP
was greater than the sewage TP. It is unlikely that all the sewage
insoluble phosphorus could be instantly converted to SOP when sewage
is mixed with RS. Also, it is well known and easily demonstrated
that the RSSS readily release SOP under anaerobic conditions. The
RS was therefore considered as the logical source for the SOP in-
crease in the ML.
Sewage and effluent samples were also analyzed for SOP
and TSP in several studies. The difference between TSP concentration
and SOP concentration in the sewage was consistently greater than
1 mg/L-P. In the aeration tank effluent, however, as well as in
the plant effluents, the difference between TSP concentration and SOP
concentration was consistently only 0.2 - O.U mg/L-P. This indicated,
that in the activated sludge process the MLSS rapidly degrade or
remove and retain soluble poly-and organic-phosphorus compounds.
41
-------
EFFECT OF MLSS-02 UPTAKE RATES AND AIR APPLICATION RATES ON SOLUBLE
PHOSPHORUS UPTAKE IN AN AERATION TANK.
In the activated sludge process the aerobic microorgan-
isms require C, P, N, etc., from sewage in order to maintain their
metabolic and reproduction activity. The amount of dissolved oxygen
in the ML is dependent on the air application rate, the oxygen trans-
fer efficiency of the aeration devices employed, and the oxygen
demand rate of the microorganisms. The aerobic microorganisms in the
ML also require sufficient amounts of dissolved oxygen for these
activities.
Numerous reports in the literature have shown that the
ML dissolved oxygen level is a significant activated sludge process
parameter affecting soluble phosphorus removal (2,3,5,22). Accord-
ingly, the effect of air application rate was evaluated using three
tanks of the East Plant. This experiment was not performed on a
plant scale because the MLSS level and plant loadings could not be
controlled from day to day.
Oxygen utilization rate measurements have been frequently
used to assess the metabolic activity or proportion of viably active
cells in MLSS. In the literature no information was discovered on the
relation of MLSS-02 uptake rate to ML-soluble phosphorus levels. The
establishment of such a relationship would provide a means to assess
the MLSS capability to remove soluble phosphorus in the activated
sludge process.
Preliminary DO-profile studies of aeration tanks resulted
in the selection of tanks 8, 9, and 11 of the East Plant for this
study because these tanks had similar air distribution patterns
(Figure 8). The ML flows to the three tanks were maintained at 7.5
mgd each with 30$ RS to provide 6 hours detention time in each tank.
The experiments were started at 2 PM when the ML oxygen demand rate
due to high sewage BOD was usually at its peak. The air application
rates tested during this four day study were as follows in Table 9.
TABLE 9
AIR APPLICATION RATES
Tank No. CFM Cu. ft./gal sewage
8 2300 0.57 33? below normal
9 3500 0.86 Normal Rate
10 U700 1.16 33% above normal
42
-------
00
5.0
4.0
3.0
O
2.0
1.0
TANK 8
TANK 9
-AIR 3350 CFM
-AIR 3450 CFM
TANK 11 AIR 3500 CFM
0 I 23456789 10 I 234I5678920ITPI OI98765W32II09 87654321
INLET TURN POINT OUTLET
HEADER NUMBER
FIGURE 8 AERATION TANKS DO PROFILES ( 9-30-1969, 8:00 A.M.)
-------
The changes observed in the tank DO-profiles resulting
from these air application rates are shown in Figure 9. The difference
in the DO-profiles given in Figure 8 and Figure 9 is partly due to the
different BOD loadings on these tanks when the DO-profile data was
taken. At the start of each daily run, the 1 PM to 2 PM hourly
composite of screened sewage was taken to the laboratory for BOD, SS,
TP and TSP analyses. In addition a 7 liter grab sample of EPRS was
taken at the same time and analyzed for SS and TSP. At 2 PM (zero
detention time) ML-DO readings and a 7 liter grab sample of ML was
taken at the inlet of each tank. The ML samples were immediately
filtered and analyzed for TSP and soluble BOD. A portion of the un-
filtered ML sample from each tank was analyzedfor SSjpHancl MLSS-Og
uptake rate. This procedure was repeated every hour at sampling
locations along the aeration tanks based on the detention time to
follow the plug flow of ML through the aeration tank.
The ML final pH levels did not change significantly due
to the changes in air application rates as shown below in Table 10.
TABLE 10
Effect of Air Application Rate on ML pH
Air Rate
cu.ft./gal
0.57
0.86
1.16
The process parameter data for these runs as presented
in Table 11 are based on 6 hours detention, 115.5 mgd sewage flow,
30% RS, and a MLVSS content of 68.9$. The data, listed in Table 11,
showed that in an aeration tank at a given time the air application
rate of 0.57 cu. ft./gal of sewage was inadequate for good phosphorus
removal. However, an aeration rate of 0.86 cu. ft./gal of sewage or
greater exhibited significantly improved phosphorus removals as
indicated by the low TSP residuals in the aeration tank effluent.
The hourly data from the four runs showed little vari-
tion. As a result, the daily data was averaged and plotted in
Figures 10, 11, 12, and 13. Figure 10 indicates, that to maintain
a DO of at least 2.0 mg/L in the aeration tank beyond the turnpoint,
an air application rate of at least 0.86 cu. ft./gal. was required.
44
-------
-P-
Ul
8.0
6.0
O
o
ci
4.0
2.0
TANK 8--
TANK 9 —
TANK II —
--AIR 2300 CFM
AIR 3600 CFM
— AIR 4800 CFM
— -r —I~N~I r — ^—i
01 23456789 10
INLET
23456789 20 I TPIOB8765432I 10 98765432 I
TURN POINT OUTLET
HEADER NUMBER
FIGURE 9 AERATION TANKS D.O. PROFILES (10-6-1969, 12:30RM. )
-------
Date
TABLE 11
DAILY PROCESS PARAMETER DATA (Detention time controlled to 6 hours)
At Tank Outlet
F/M
Aeration
Tank
10-6
Won.
10-7
Tues
10-8
Wed.
10-9
Thurs.
8
9
11
8
9
11
8
9
11
8
9
11
0.517
0.5^7
0.635
O.U57
TP/M
0.031+9
0.0196
0.0215
0.0159
MLSS
mg/L
2530
2610
2770
2910
Air
cu. ft. /gal.
0.57
0.86
1.16
0.57
0.86
1.16
0.57
0.86
1.16
0.57
0.86
1.16
ML-DO
mg/L
1.0
6.0
7.8
«
«
«
0.5
1.2
3.5
0.5
1.0
2.5
ML-TSP
mg/L-P
6.U
0.3U
0.28
1U.U
0.2U
0.18
11.5
0.20
0.16
9.7
0.2U
0.2U
ML
Soluble
BOD
mg/1
9.1*
U.U
u.u
ll*.U
5.U
U.2
15. k
5.6
5.8
lU.o
6.2
5.U
* D. 0. meter inoperative
-------
o
I
o
Q
A 2300 C.FM. ME. 4 RUNS
O 3500 " " 4 ii
X 3600 " " 6 "
• 4700 'i " 4 "
234
DETENTION HOURS
FIGURE 10 EFFECT OF AIR APPLICATION
RATE ON ML-DO LEVEL
47
-------
60
10
CO
40
30
cc
UJ
20
CM
O
10
2300 CFM AVE. 4 RUNS
3500 " i' 4 i'
3600 " " 6 ii
4700 n ii 4 n
234
DETENTION HOURS
FIGURE 11 EFFECT OF AIR APPLICATION RATE
ON MLSS-02 UPTAKE RATE
48
-------
20
A 2300 CFM AVE. 4 RUNS
O 3500 " " 4 "
X 3600 " - 6
• 4700 " " 4 »
234
DETENTION HOURS
FIGURE 12 EFFECT OF AIR APPLICATION RATE
ON ML-TSP LEVEL
49
-------
o
o
CD
UJ
_l
GO
-I 20 -
2300 CFM AVE 4 RUNS
3500 " " 4 "
3600 " " 6
4700 " " 4
10 -
234
DETENTION HOURS
FIGURE 13 EFFECT OF AIR APPLICATION RATE
ON ML-SOLUBLE BOD LEVEL
50
-------
Aa plotted in Figure 11, MLSS-Og uptake rates observed in
this study at 0-hour detention time in the aeration tank were about
half of the values reported by Eckenfelder (37). This may be due to
approximately 20 minutes aeration of the ML in the long feed channels
prior to entrance of the ML into the aeration tanks.
TABLE 12
MLSS-02 UPTAKE RATE AFTER 6 HOURS AERATION
AIR APPLICATION RATES mg 02/gm VSS/hr.
CFM cu. ft./GAL.
2300 0.57
3500 0.86
U700 1.16
The above values in Table 12 compare favorably with those reported by
Okum and Lynn (38) of 22 to 28 mg 02/gm VSS/hr. At no time were the
endogeneous oxygen uptake rates of 1.9 to 9.8 mg 02/hr/1000 mg sludge
as reported by Eckenfelder (37) observed. An examination of Figures
12 and 13 indicates that an aeration rate of 0.57 cu.ft./gal. of
sewage was insufficient for soluble phosphorus removal but did not
affect the BOD removals.
AVERAGE
(U RUNS)
32. U
25.1
23.8
RANGE
LOW
28.9
22.3
19.5
HIGH
36.0
27.1
26.1
51
-------
EVALUATION OF MLSS METABOLIC ACTIVITY BY GLUCOSE DEHYDROGENASE ASSAY
Observations of the daily process parameters data
indicated that they are sufficient to explain why poor or good
soluble phosphorus removal occurs in the Milwaukee activated sludge
plants. Ford, Young and Eckenfelder, (39) investigated the use of a
glucose dehydrogenase assay for evaluating the biological activity of
sludges. It was then thought that if the removal of soluble phospho-
rus in the activated sludge process could be related to the biological
activity of the MLSS, this additional information could probably
explain the observed deviations.
In an aeration tank, the oxygen uptake rate of the
MLSS decreases with increasing detention and air application rate
(Refer to Figure 11). Thus, the metabolic or oxidative activity as
represented by the MLSS-glucose dehydrogenase activity could be ex-
pected to decrease from the tank inlet to the tank outlet and perhaps
coincide with the SOP being removed by the MLSS.
The data of Ford, et. al. (39) showed that the MLSS-
glucose dehydrogenase activity within a sampling location exhibited
a very large coefficient of variation (C.V.). They performed one
hundred triplicate analyses on samples from three sampling locations
and obtained C.V.'s of 31.6$, 2H.5/& and 23.8$ respectively.
For this study to be worthwhile it was necessary to
determine whether the large variation in MLSS-glucose dehydrogenase
activity reported by Ford was caused by the assay itself or was
caused by the samples that were taken from a specific sampling site.
In this study, seven liter ML samples taken from the inlet, turn-
point and outlet of an aeration tank were each analyzed in triplicates
for MLSS and MLVSS (Appendix B) and glucose dehydrogenase activity.
The standard deviation of the dehydrogenase assay was
calculated from the grand average range of the range of triplicate
analyses per sample (19 samples from each of three sampling sites)
according to the procedure given by Natrella (Uo). The values
used in this calculation were the range of triplicate determinations
per sample as shown in Table 13.
52
-------
TABLE 13
DEHYDROGENASE ASSAY VARIABILITY
( ^iM TPF/5 ml of ML)
SAMPLING RANGE OF TRIPLICATES STANDARD
SITE AVERAGE HIGH LOW DEVIATION
INLET .032 .072 .013 .0189
TURNPOINT .OU9 .097 .000 .0289
OUTLET .050 .18U .000 .0295
The actual value from the assay used in calculating MLSS-glucose
dehydrogenase activity for each sample was the average of the
triplicate analyses for each sample. These values exhibited
wide variations for the ML samples analyzed as shown in Table lU.
TABLE lU
DEHYDROGENASE ASSAY DATA
TPF/5 ml of ML)
Sampling Average Range
Site High Low
INLET 0.822 1.150 O.U15
TURNPOINT 0.762 1.0U3 0.285
OUTLET 0.729 1.051 0.212
The comparison of data in Tables 13 and lU indicated that the
reproducibility of the assay was fairly good and that the wide
variations in MLSS-glucose dehydrogenase activity was due to
the samples which were taken within a sampling site for analyses.
53
-------
The variability of the MLSS-dehydrogenase activity according
to sample sources (same 19 runs) was also determined as shown in
Table 15• The MLSS-dehydrogenase activity was expressed as juM TPF/mg
MLVSS (jiM Triphenylformazin produced/mg MLVSS).
TABLE 15
VARIABILITY OF ML - DEHYDROGENASE ACTIVITY AND MLVSS
AT DIFFERENT SAMPLE LOCATIONS
Aeration Tank ML-Dehydrogenase Activity MLSS
Sample
Location
Inlet
Turnpoint
Outlet
Average
MLVSS
Average
uM TPF/mg MLVSS
0.072
0.068
0.063
Standard %
Deviation CV
0.
0.
0.
01U9
0130
OlUl
20
19
22
20
.7
.1
.U
.7
Ave.
mg/1
3030
3160
3130
Ave.
Std.
$VSS Dev.
75.
7lt.
73.
2
3
9
0.
0.
0.
89
89
79
i
CV
1
1
1
1
.18
.20
.07
.15
Std. Dev. = Standard Deviation
The above data continued to show that the large variation in the
glucose dehydrogenase activity within a sampling site was due to the
variation from sample to sample. The CV of the MLSS-glucose
dehydrogenase activity at different sample locations conform to those
reported by Ford as shown in Table 16.
TABLE 16
COMPARISON OF COEFFICIENTS OF VARIATION (C.V.)
Milwaukee Data
Sample Location % C.V.
Aeration Tank Inlet 20.1%
Aeration Tank Turnpoint 19.1$
Aeration Tank Outlet 22.U^
Average
Ford's Data
% C.V.
31.652
Sample Location
Contract Tank
Stabilization Tank
(Sampling Point A*)
Stabilization Tank
(Sampling Point B*)
•Sampling Location Not (39)
Specified in Reference
23.!
The usage of the glucose dehydrogenase assay to evaluate
the metabolic or oxidative activity of the MLSS in an activated
sludge plant was found to be of little practical value as a large
number of samples would have to be analyzed to provide significant
54
-------
data. It should be noted that the data on the average did shov that
the MLSS-glucose dehydrogenase activity decreases with increasing
detention time, (aee Table 15).
Jones and Prasad (1*1) made a detailed study on the use of
tetrazolium salts as a measure of sludge activity. They concluded
that, "The TTC dehydrogenase test in mixed cultures and complex
substrates at best can be considered as a gross measurement of
activity. The interpretation of the data should be approached with
caution particularly if it is being used as a research tool."
55
-------
X-RAY DIFFRACTION STUDIES OF SEWAGE SUSPENDED SOLIDS AND WASTE SLUDGE
SOLIDS
In the literature, the removal of sewage phosphorus by the
activated sludge process has been attributed to cationic precipi-
tation or biological uptake, or a combination of both. Therefore, a
knowledge of the mechanism or mechanisms prevailing would not only
enable us to obtain a better understanding of the phosphorus removal
process but also to develop concepts for the improvement of phosphorus
removal in the activated sludge system. Many cations (iron, aluminum,
calcium and magnesium) have been successfully added to aeration units
by many investigators to enhance the removal of soluble phosphorus.
If a qualitative and quantitative procedure to determine the presence
of these inorganic phosphate compounds in sewage suspended solids and
waste sludge solids were available, the mechanism of phosphorus re-
moval by the activated sludge process could be better explained.
Accordingly, staff members of Marquette University, Milwaukee
were consulted on the use of X-Ray diffraction analysis to determine
if these inorganic phosphate compounds were present in the sewage
suspended solids and waste sludge solids.
The preliminary X-Ray diffraction studies (U2, 1+3, kh) re-
vealed that a crystal-like compound in the 103°C oven dried RS gave
an X-Ray diffraction pattern very similar to that of Iron (ill)
orthophosphate (FePO^). This observation could not be confirmed and
studied further because of the appearance of too many background lines
in the X-Ray diffraction patterns obtained in the subsequent studies
due to amorphous material in the sludge. The sludge samples were
then heated at different temperatures to see if the background dark-
ness could be decreased. Heat treatment of the samples (500°C to
600°C) decreased the background darkening considerably, but this high
temperature heat treatment changed the nature of the compound formed
and resulted in a homogeneous mass.
Freeze drying of the sample was tried. This did not help
in decreasing the background but did result in a heterogenous mass
containing some black crystals. These black crystals were separated
and found to give patterns similar to vivianite, Fe3 (PO^^ • 8H20.
Further research will be conducted in an attempt to purify and
evaluate the concentration of these black crystals. Magnetic
separation techniques are currently under study and show promise of
success. These X-Ray studies are being continued under Project
Grant Number 11010, FLQ, "Phosphorus Removal With Pickle Liquor
In A 115 MOD Activated Sludge Plant".
56
-------
CATIONIC REMOVAL OF PHOSPHORUS FROM SEWAGE
A number of investigators have studied the ability of
certain cations (Pe"1"*"*", Fe++, Al'M"f, Ca^, and MR"*"*") to enhance the
soluble phosphorus removals in the activated sludge process. Very
little information is available in the literature on the concentrations
of these soluble cations in sewage and their effect on sewage phospho-
rus removal. Studies were undertaken to assess the role of Fe, Al,
Ca and Mg ions, normally present in Milwaukee sewage, in the removal
of SOP by the two Milwaukee activated sludge plants.
Currently, it was assumed that the insoluble cations (i.e.,
the cations present in the sewage suspended solids) are tied up
possibly as Fe(OH)3 and are not available for reaction with SOP to
form insoluble phosphate compounds during the activated sludge
process. A comparison of the influent and of the effluent soluble
cation concentrations would indicate if these cations were removed in
the activated sludge process. It was hypothesized that if a decrease
in the soluble cation concentration was observed, this decrease was
due to the formation of an insoluble phosphate compound through its
reaction with SOP.
The cation analyses were performed on the unneutralized
ternary acid digestate of 2U hour composite samples of screened
sewage, EP and WP effluents by atomic absorption. The initial work
was carried out using the 2U hour composite samples to determine if
there was a significant change in the soluble cations concentrations
on a daily basis during July of 1969. The daily data exhibited
marked fluctuations because of the limited experience on the atomic
absorption unit by laboratory personnel. Therefore, only monthly
averages are presented in Table 17
57
-------
TABLE 17
AVERAGE CATION CONCENTRATIONS (mg/L) FOR JULY, 1969
TOTAL CATION CONCENTRATIONS TOTAL SOLUBLE CATION CONCENTRATIONS
Screened Effluent Screened Effluent
Cation Sewage WP EP Sewage WP El?
4--I- ~l "I -I-
Fe & Fe 5.00* 0.71 0.59 0.55 0.32 0.29
Al 2.00 0.53 0.41 0.44 0.33 0.27
Ca++ 52.4 48.8 47.9 48.6 47.7 47.2
Mg++ 31.8 30.7 30.2 30.4 30.5 30.3
^Partly influenced by filtrate from vacuum filters
The above data showed that both activated sludge plants
removed very little of the soluble cations of Fe, Al, Ca and Mg.
Based on this data, the removal of SOP in the Milwaukee activated
sludge plants by the sewage soluble cations would be very insignifi-
cant. From the above data one could assume that the cationic fix-
ation of soluble phosphorus probably takes place in the sewage prior
to its reaching the plant. The consistently low amount of total
soluble iron in Milwaukee sewage (usually< 1.0 mg/l-Fe) may be due
to the low solubility of the iron phosphate compound present in the
sewage suspended solids.
The initial X-Ray diffraction studies on the 103°C dried
sludge samples indicated that one of the insoluble cation phosphate
compounds was possibly FePO^ which in the wet sludge may be present
as FePO^v. 2H20 or FePO^ • 4H20. The theoretical solubility product
of FeP04 o 2H20 is 1 x 10"33 in distilled water according to Chang
and Jackson (45). The solubility product of FePO^ » 2H20 in sewage
was calculated from the observed data and was found to average 6.7 x 10"22
at pH 8.0. This higher value would be expected since sewage contains
substances, such as detergents, polyphosphates, chelating agents, salts
and other unknown compounds which could increase the solubility of
FePO^ . 2H20 in sewage. The above assumptions are reasonable because
the calculated solubility product agreed with that reported by Galal-
Grochev and Stumm (46) of 1 x 10~23 at a pH greater than 7.0 at 25°C
for FePO^.
58
-------
Since the activated sludge process removes polyphosphates,
surfactants, etc., from sewage the solubility product of ferric
phosphate would be expected to decrease. The calculated solubility
product of FePOij « 2HoO in ML after 6 hours aeration was found to
decrease to an average of 1.3 x 10 ^ at pH 7.0.
59
-------
EFFECT OF IRON ADDITION TO AN AERATION TANK ON SOLUBLE PHOSPHORUS
REMOVAL
During June and July of 19&9 the TSP and SOP removal
efficiencies for both plants dropped from an average of 80$ to an
average of hQ%. The period of reduced removals coincided vith the
breweries shutdown which was discussed in a previous section. This
was an opportune time to begin a cationic addition experiment, since
this period of extremely reduced SOP and TSP removals could provide
more reliable and significant data on the cationic removal of soluble
phosphorus.
This phase of the study was a cooperative venture with the
A. 0. Smith Corporation of Milwaukee, who supplied the cationic com-
pound, ferrous sulfate as waste pickle liquor needed for the addition
of iron to the ML. The industrial waste used contained from O.U to
1.0 pound of iron per gallon and usually had a pH of about 1.0.
Neutralized and unneutralized pickle liquor were used in this study.
The initial work was limited to the addition of iron to one
of the aeration tanks of the EP. This approach was taken to determine
the effective iron dose, the desired addition site, and the material
handling problems associated with the pickle liquor addition. We
were also interested in determining if this waste product would have
any detrimental influence on the activated sludge process or on the
air diffuser plates.
The waste pickle liquor was first added to the aeration tank
at the turning point, providing 3 hours detention, and then at the
inlet, providing 6 hours detention. The ML flows to the aeration
tanks were held at 7.0 to 7.5 mgd to provide about 6 hours detention,
and the air application rate was maintained at approximately 3200 cfm.
The iron was added 2U hours'/day from Monday to Friday and the pickle
liquor addition rate was manually controlled. This study was conducted
for two periods of three weeks each. An adjacent aeration tank with
the same ML flow and aeration pattern was used as a control. The
experimental and control tanks ML were sampled at the inlet, turn-
point and outlet every 2 to 3 hours continuously. The ML samples
were analyzed for total iron, total soluble iron, TP, TSP, MLSS, pH,
and ML-SDI, and ML-DO at the tank outlets.
The iron dosing rates maintained were approximately 7.5, 15,
and 30 mg/L-Fe based on the hourly ML flow. The averages of the bi-
hourly and trihourly data by week are presented in Table 18 . The
data such as given in Table 18 showed that the addition of ferrous iron
in the form of waste pickle liquor was very effective in the reduction
of ML-TSP. Actual iron dosing rates of 11.0 to 27.U mg/L-Fe (based on
ML flow) resulted in average ML-TSP residuals between 0.23 to 0.1+9 mg/
L-P and reduced the inlet ML-TSP levels (3.5 to 8.5 mg/L) by 77.3 to
60
-------
TABLE 18
EFFECT OF IRON DOSAGE ON ML-TSP LEVEL
Run
No
1
2
3
k
5
6
Date Iron Add!
1969 Dosage
mg/L-F
7/1 to 7/3
7/8 to 7/11
7/15
to 7/18
8/U to 8/8
8/11
8/18
to 8/15
to 8/22
11.0
6.8
27. U
30.0
15.0
13.3
15.5
17.0
tion Average ML-TSP rag/L-P
(1) Site Inlet (2) Outlet (3)
'e
TP (U)
TP
TP
(5) pa3t TP (6)
(5) past TP
Inlet
Inlet
Inlet
Exptl. Control
Tank Tank
3.
U.
U.
u.
2.
5.
6.
8.
5
85
65
1
8
U
9
5
0.
1.
0.
0.
0.
0.
0.
0.
U6
1
U6
31
23
UO
U5
U9
1.9
2.8
2.5
2.0
0.76
0.88
1.2
1.1
% Reduction
ML-TSP
Exptl.
Tank
86.9
77.3
90.1
92. U
91.8
92.6
93.5
9^.2
Control
Tank
U5.7
U2.3
U6.3
51.2
72.9
83.7
82.6
87.1
(l) Dosage based on Pickle Liquor iron analyses
(2) Average of experimental and control tanks inlet ML-TSP
(3) Outlet ML samples (6 hours detention)
(U) TP « tank turnpoint and is 1/2 of tank length
(5) In run 3 these dosages are estimates
(6) Past TP (2 hours detention)
-------
All three iron addition sites (2,3 and 6 hours detention)
were found to be effective, provided there was sufficient ML-DO.
The role of ML-DO level on the effectiveness of ferrous iron in TSP
removal was observed in run 6 and a typical observation at an aeration
rate of 3600 cfm. is given below in Table 19
TABLE 19
RUN 6 OBSERVATION DATA
Turnpoint Outlet
D.O. MG/L ML-TSP MG/L D.O. MG/L ML-TSP MG/L
Control Tank 2.7 1.1 5.0 0.35
Experimental Tank 0.5 5.2 6.6 0.22
In Table 18 it can be seen that the average removal of TSP
by the MLSS in the control tank was much better in runs U, 5 and 6
than in runs 1, 2 and 3, even though the inlet average ML-TSP levels
were much higher in runs U, 5 and 6 compared to the early runs. This
difference is attributed to the effect of the breweries waste water on
the Milwaukee plants. First, the initial iron addition runs (7-1-69
to 7-18-69) were carried out during the breweries shutdown period
(6-9-69 to 7-15-69) when the daily soluble phosphorus removals
averaged less than UO/J. In the second set of runs (8-U-69 to 8-22-69)
the breweries were back in operation and the daily soluble phosphorus
removals improved to an average of greater than 80$. The results in-
dicated that the addition of ferrous iron as pickle liquor to ML was
effective in maintaining low residuals of TSP in ML after 6 hours of
aeration.
Added soluble ferrous sulfate as pickle liquor was rapidly
incorporated into the MLSS. This was found by the analysis of ML
samples for total soluble iron taken at ten foot interval sampling
points from the iron addition site at the tank turnpoint as shown in
Table 20.
62
-------
TABLE 20
REDUCTION OF SOLUBLE IRON CONCENTRATION IN AN AERATION TANK
(Iron * was added as waste pickle liquor at the aeration tank turnpoint)
DISTANCE FROM TOTAL SOLUBLE IRON
TANK TURNPOINT FOUND IN THE ML
(FEET) (mg/L-Fe)
10 i.iu
20 l.lU
30 0.58
UO 0.50
50 0.56
60 0.58
70 O.HI»
80 O.UU
90 O.U3
* Iron dosing rate 7.5 ng/L - Fe based on ML flow.
The average ML total soluble iron concentrations at the inlets
and outlets were practically the same, 0.23 to 0.39 mg/L-Fe
respectively during the 6 test runs in the experimental tank.
The iron added, as obtained by calculation, from
the pickle liquor data compared favorably with the average total
iron found in the inlet and outlet MLSS as shown in Table 21«
The clarifier detention times are approximately
2 to 3.5 hours. During this time period it has been previously
shown that soluble phosphorus is released from the solids. Ten
iron and phosphorus tests were performed in the laboratory with
the samples of ML from the control and experimental tanks outlet
and then the release of phosphorus and iron after two hours
detention was determined. The average results of the ten test
runs as given in Table 22 , indicate that in a period of 2 hours
the MLSS treated with iron release less TSP than the untreated MLSS
from control tanks and that the iron treated MLSS released more
soluble iron than the untreated MLSS.
63
-------
TABLE 21
AVERAGE IRON RECOVERIES
Run
No.
1
2
3
U
5
6
Planned Iron Calculated Iron
Addition Rates Addition Rates
gpm
1.0
0.5
2.0
2.0
1.0
1.0
0.5(b)
1.0
1.0
mg/L-Fe
15
7.5
30
30(a)
15(a)
15
15
15
15
mg/L-Fe
11.0
6.8
27. U
13.3
13.2
15.5
17.0
Actual Iron Found Observed Average
In the Outlet MLSS Recovery of Added
mg/L-Fe
Exptl
Tank
70.6
55.0
80.5
8U.3
75.1
68.5
78.1
90. U
Control
Tank
59.2
U9.9
56.7
60.8
60.0
55.9
59.8
7U.U
Iron Dose
rag/L-Fe
11. U
5.1
23.8
23.5
15.1
12.6
19.0(c)
16.0
(a) Iron dosing rate estimated from pickle liquor specific gravity.
(b) Concentrate (undiluted pickle liquor)
(c) The large difference in run 5 may be partly due to inadequate manual
control of pickle liquor flov.
-------
TABLE 22
SOLUBLE IRON AND TSP RELEASE BY MLSS
(average of 10 tests)
Control Tank
Detention Hours 0 hour 2 hours
Total soluble Iron 0.21 0.30
mg/L-Fe
TSP rag/L-P 1.6U 3.01
Experimental Tank
0 hour
0.27
0.29
2 hours
0.71
1.15
In general, the neutralized and the unneutralized
waste pickle liquor were observed to have no detrimental effect on
the activated sludge process. This was shown by the experimental
and control tanks ML having similar pH's, MLSS-Og uptake rates, SDI
values. Microscopic examinations showed no changes in the biota.
In this limited study no apparent clogging of aeration tank diffuser
plates was observed.
65
-------
PLANT SCALE IRON ADDITION STUDY
This was a feasibility study of plant scale iron addition for
improved soluble phosphorus removal during a two week period. The
EP was used as the experimental plant and the WP as the control.
The iron was added in the form of ferrous sulfate as unneutral-
ized pickle liquor, a waste product which was supplied by the A. 0.
Smith Corp. Milwaukee, in a cooperative venture. The A. 0. Smith
Corp. also provided personnel to monitor the pickle liquor iron
concentrations and to control the iron dosing rate 2U hours a day.
The pickle liquor was added to the EP sewage feed channel 65
feet upstream from the EP RS feed pipe. The ferrous iron concent-
ration in the pickle liquor was determined by titration with 0.10N
potassium dichromate. The iron addition rate was then based on the
pickle liquor iron content and the hourly ML flow rate. A dosing
rate of about 15 mg/L-Fe based on the ML flow was used from 11/3
to 11/7 (2U hours/day for U-l/3 days) during which a total of
110,898 gallons of pickle liquor (7U,300 pounds of iron) was added
to the ML. From 11/10 to 11/lU (2U hours/day for U-l/3 days),
52,3U5 gallons (37,200 pounds of iron) of pickle liquor was added
to ML for a dosing rate of about 7.5 mg/L-Fe. The sampling pro-
cedures and the analytical methods used were as described in pre-
vious sections. The data from the 2k hour WP and EP composite
effluent samples do not readily show the effectiveness of the
added iron in reducing the effluent residual SOP as shown in Table
.23. However, a comparison of the SOP content of the sewage and
EP effluent bihourly composite samples (Figure lU) illustrates
very dramatically that a 15 mg/L-Fe dosing rate consistently pro-
duced an effluent SOP residual of 0.05 mg/L-P for U-l/3 days.
The 7.5 mg/L-Fe dosing rate was not very effective as shown in
Figure lU.
In the previous section it was found that in an aeration tank
the added soluble iron was rapidly removed, and did not appear to
significantly increase the ML total soluble iron content. This was
also observed during this study in the daily data from both plant
effluents. The total soluble iron in the plant effluent averaged
0.3U mg/L-Fe for the WP and 0.31 mg/L-Fe for the EP.
Plotted in Figure 15 are the WP and the EP SDJ and MLSS shift
averages on a daily basis. The plots show that during this study
period the ML settleability fluctuated with a weekly cycle,
improving on Sunday, Monday and Tuesday and deteriorating steadily
from Wednesday to Saturday for both the plants. The plot also
shows that an iron dosing rate of 15 mg/L-Fe was more effective
than the 7.5 mg/L-Fe dosing rate in improving the settleability (SDI)
66
-------
No Iron Addition
TABLE 23
EFFLUENT SOP mg/L-P
Iron Addition
No Iron Addition
10/27/69 to
11/2/69
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
Date
10-27
10-26
10-29
10-30
10-31
11-1
11-2
WP
o.ii*
0.16
0.1*5
0.1*5
0.51
0.13
0.10
EP
0.15
0.21
O.U6
0.32
0.25
O.ll*
0.11
15 mg/L-Fe
11/3/69 to
11/9/69
Date
11-3
11-U
11-5
11-6
11-7
11-8
11-9
WP
0.17
0.10
0.19
0.53
0.82
0.31
0.10
EP
0.07
0.05
0.05
0.05
0.06
0.05
0.18
7.5 mg/L-Fe
11/10/69 to
11/16/69
Date
11-10
11-11
11-12
11-13
ll-ll*
11-15
11-16
,WP
O.U6
0.59
0.60
0.70
0.99
0.27
0.13
EP
O.Ul
0.12
0.22
0.27
0.1*1*
0.19
0.1*7
11/17/69 to
11/23/69
Date
11-17
11-18
11-19
11-20
11-21
11-22
11-23
WP
0.20
0.31
0.21
0.30
0.53
O.U5
0.23
EP
1.6
0.75
0.58
0.52
0.70
0.31
0.1*1
Note: Iron added only to the East Plant
Dosing Rate: 15 og/L-Fe; 7 A.M. - 11/3/69 to 3:30 P.M. on 11/7/69
7.5 mg/L-Fe; 7 A.M. - 11/10/69 to 1:05 P.M. on ll/lU/69
-------
10/27/69 TO 11/21/69
LEGEND
SEWAGE SOP
EFFLUENT SOP
00
5.5
5.0
40
a
o
2JO
LO
NO IRON ADDITION
IRON ADDITION
I5MG/L - FE
NO IRON
ADDITION
IRON ADDITION
75 MG/L - FE
NO IRON ADDITION
I T I
M M
1
M
I
M
1
M
I
M
I
M
I ' I
M M
T
M
\
M
I
M
I 'I
M M
I' I
M M
I "I
M M
I
M
SU I M
W | TH
SA I SU
TH
SA | SU
W | TH
SA | SU
W | TH
SA
FIGURE 14 EFFECT OF IRON ADDITION ON EAST PLANT RESIDUAL SOP
-------
1.20
LEGEND
O OWEST PLANT
EAST PLANT
FIGURE 15 COMPARISON OF EAST 8 WEST PLANT SDl'S 1969
-------
of the EP MLSS when compared to that of the WP MLSS. This was
probably due to the iron accumulation in the MLSS which increased
the density of EP MLSS.
The accumulation of added iron in the East Plant Return
Sludge with time is plotted in Figure 16. The data was obtained from
RS samples taken continuously at intervals of 2 hours.
The first iron addition (15 mg/L-Fe) began at 7 A.M. on
11/3/69 and the accumulation of the iron in the RSSS (approximately
2.5$) was observed to begin with the U P.M. sample on 11/3/69. From
this point, the iron continued to accumulate in the RS until 8 A.M.
on Thursday, 11/6/69 (6U hours of iron addition) and then the RS
iron content stayed at a fairly constant level (at an average of
6.01$) until midnight of 11/7/69 (next 1+0 hours). This indicated that
an equilibrium condition was reached when the iron wasting rate (i.e.,
the iron in EP-WS) was equivalent to the iron addition rate. From
U A.M. on Saturday 11/8/69 the EP-RS iron content slowly decreased due
to the cessation of iron addition.
The second iron addition (7.5 mg/L-Fe) was started at 7 A.M.
on Monday 11/10/69* Figure 16 shows that at this iron addition rate
the iron did not show any further buildup in the EP-RS (average 5.26J5).
This indicated that the equilibrium iron concentration was reached for
these iron dosing and sludge wasting rates. After iron addition was
stopped at 1 P.M. on Friday ll/lU/69, the RS iron content was observed
to continually decrease from 5.26$ at 10 P.M. on Friday until it
approached the initial RS iron level of 2.5% on Thursday, 11/20/69.
The total phosphorus contents were also determined on these
bihourly RS samples. These values are also plotted in Figure 16. A
comparison of the RS phosphorus and iron plots reveals that the
phosphorus did not accumulate in the RS to the same extent that the
iron accumulated.
It was anticipated that the accumulation of iron in EP-RS
would increase its ash content, and the effect of the increased ash
would be to reduce nitrogen content of the RS.
Each day, one liter sample of WP and EP-RS were centrifuged
and the concentrated solids dried at 10U°C for 2U hours. Ash and Total
KJeldahl Nitrogen (AOAC-2.Q1+2 and 2.0U3, reference 36) analyses were
performed on the dried material. In Figures 17 and 18 are plotted the
results of these daily analyses. These figures show that as iron
addition continued the EP-RS ash content progressively increased as the
iron was added, and the EP-RS ash content was much higher than that of
the WP-RS. When iron addition was stopped on ll/lU/69 the EP-RS ash
content decreased as the accumulated iron was removed from the system
as waste sludge.
70
-------
/v\
z
o
cr
-IRON ADDITION -
15 M6/L
-NO IRON-
-IRON ADDITION-
75 MO/L
-NO IRON
NMNMNMNMNMNMN MN MNUNMNMNMNMNMN MNMNHNMN
11/3 HON | 11/4 TUE. | 11/3 WED | II/6THUB | 11/7 FRI | 11/8 SAT | 11/9 SUN. | 11/10 MON | 11/11 TUL | 11/12 WED | II/I3THUR | 11/14 FRI. | 11/15 SAT. | 11/18 SUN | 11/17 MON | II/B TUES | 11/19 WED | II/2OTHUR.| IU2I |FRI.
FIGURE 16 ACCUMULATION OF IRON IN EP-RS
1969
-------
30--
2 29
CD
28--
O)
cc
I
tf) 27
26--
25--
24
LEGEND
WEST PLANT
A A EAST PLANT
IRON ADDITION:
I5MG/L; 7A.M. 11/3 TO 3:30 PM. 11/7
75 MG/L;7A.M. 11/10 TO l:05PM 11/14
IRON
15 MG/L
IRON
75 MG/L
16
10/27-I I/I su 11/2- 11/8 SU 11/9-11/15 SU 11/16-11/20 su
FIGURE 17 RETURN SLUDGE ASH CONTENT (DRY BASIS)
1969
72
-------
6.7 -
6.6
(O 6.5
<
CD
QC.
O
6.4 -
Id
O
tr
H
z
^o
6.3 -
6.2 •
6.1 •-
6.0
LEGEND
O OWEST PLANT
£ 6 EAST PLANT
IRON ADDITION:
15 MG/L; 7A.M. 11/3 TO 3:30PM 11/9
75MG/L; 7AM 11/10 TO I:05PM. 11/14
IRON
75 MG/L
16
10/27-ll/l SU 11/2-11/8 SU 11/9-11/15 SU 11/16-11/20 SU
FIGURE 18 RETURN SLUDGE NITROGEN CONTENT
(DRY BASIS)
1969
73
-------
The effect of the increased ash content was to reduce the
EP-RS nitrogen content as shown in Figure 18. The magnitude of the
effect of ash content on the nitrogen content of this waste sludge
can be obtained by a comparison of the average values of ash and
nitrogen contents of RS during the iron addition periods as shown
in Table 2k.
-------
TABLE 2U
AVERAGE RETURN SLUDGE COMPOSITION
Iron Addition
% A3h % Nitropen
WP EP Difference WP EP Difference
15 mg/L
11/3 to 11/7 25.9 29.1 3.2 6.U9 6.27 0.21
% N based on VSS (8.76) (8.85) (0.09)
7.5 mg/L
11/10 to ll/U 25.2 28.8 3.6 6.59 6.32 0.27
% N based on VSS (8.82) (8.87) (0.05)
75
-------
SECTION VII
ACKNOWLEDGEMENTS
This report was prepared by Raymond D. Leary, Chief Engineer and
General Manager; Lawrence A. Ernest, Director of Laboratory; Roland S.
Powell, Assistant Director of Laboratory; and Lawrence H. Docta, Research
Supervisor of the Sewerage Commission of the City of Milwaukee.
We acknowledge the assistance given by Mr. H. W. Poston and
Mr. C. Risley and the staff of the Chicago office of the Environmental
Protection Agency. Our acknowledgements are due to Dr. R. N. Kinman and
Dr. R. L. Bunch whose guidance from time to time as project officers led
to the completion of this project. The Commission Staff members wish to
express their gratitude to the Marquette University Staff who conducted
the statistical and X-Ray diffraction studies under the guidance of the
project consultants Dr. Raymond J. Kipp and Dr. Sudershan K. Malhotra.
The Commission commends the A. 0. Smith Corp. (Milw., Wis.) for their
cooperation and contribution of the waste pickle liquor for the iron
addition studies as well as for the assistance and cooperation of Mr.
Milton Johnson and other A. 0. Smith personnel in making that study
successful.
The assistance of Laboratory Technicians, Miss Gloria Aldenhoff,
Mrs. Minne Ness, Miss Elizabeth Merscher, and Mr. Gerald Hertzfeldt in
conducting the laboratory analyses is gratefully acknowledged.
77
-------
SECTION VIII
REFERENCES
1. Unpublished data. Sewerage Commission of the City of Milwaukee
Laboratory, Wisconsin.
2. Connell, C. H., and D. Vacker, "Parameters of Phosphate Removal
by Activated Sludge," Proceedings of the 7th Industrial Water
and Waste Water Conference, Univ. of Texas, Austin, (June 1
& 2, 1967).
3. Witherow, Jack, L., "Phosphate Removal by Activated Sludge," A
report by the U.S. Depart, of Interior, FWPCA, Robert S. Kerr
Water Research Center, Ada, Oklahoma (May 1969).
U. Menar, A. B., and D. Jenkins, "The Mechanism of Enhanced
Phosphate Removal in the Activated Sludge Process," Part II,
SERL Report 68-6, Univ. of California, Berkeley, (Aug., 1968).
5. Levin, G. V., and J. Shapiro, "Metabolic Uptake of Phosphorus by
Waste Water Organisms," J. Water Pollution Control Federation,
31,(6),800 (1965).
6. Vacker, D., C. H, Connell, and W. N. Wells, "Phosphate Removal
Through Municipal Waste Water Treatment at San Antonio, Texas,"
J. Water Pollution Control Federation, 32t(5),750 (1967).
7« Owen, R., "Removal of Phosphorus from Sewage Plant Effluents with
Lime," Sew. and Ind. Wastes, 25_, (5), 5^8 (1953).
8. Stone, T., "Iron and Phosphate Changes during Sewage Treatment,"
Sew. and Ind. Wastes, 31, (8), 98l (1959).
9« Hurwitz, E., R. Beaudoin, and W. Waters, "Phosphates, Their Fate
in a Sewage Treatment Plant-Waterway System," Water and Sew. Works,
112. (3), 8U (1965).
10. Lea, W. L., G. A. Rohlich, and W. J. Katz, "Removal of Phosphates
from Treated Sewage," Sew. and Ind. Wastes, 26, (3), 26l (195M.
11. Rohlich, G. A., "Methods for the Removal of Phosphorus from
Sewage Plant Effluents," Inter. J. of Air and Water Pollution, 7
1*27 (1963).
79
-------
12. Malhotra, S. K., G. F. Lee, and G. A. Rohlich, "Nutrient Removal
from Secondary Effluent by Alum Flocculation and Lime Precipi-
tation," Inter. J. of Air and Water Pollution, 13, U87 (196M.
13. Nesbitt, J. B., "Removal of Phosphorus from Municipal Sewage
Plant Effluents," Eng. Research Bulletin B-93, Penna.State Univ.,
College of Eng., University-Park, Penna., (1966).
lU. Tenney, M. W., and W. Sturam, "Chemical Flocculation of Micro-
organisms in Biological Waste Treatment," J. Water Pollution
Control Federation, 31, (10), 1371 (1965).
15. Barth, E. F., and M. B. Ettinger, "Mineral Controlled Phosphorus
Removal in the Activated Sludge Process," J. Water Pollution
Control Federation, 3£, (8), 1362 (1967).
16. Eberhardt, W. A. and J. B. Nesbitt, "Chemical Precipitation of
Phosphorus in a High Rate Activated Sludge System," J. Water
Pollution Control Federation, U£, (7), 1239 (1968).
17. Rudolf, W., "Phosphates in Sewage and Sludge Treatment. II.
Effect on Coagulation, Clarification and Sludge Volume",
Sewage Works J., 1£, (2), 178 (19^7).
18. Neil, J. H., "Problems and Control of Unnatural Fertilization of
Lake Waters," Proceedings of the 12th Ind. Wastes Conf., Purdue
Univ., (May 13-15, 1957).
19« Schmid, L. A., and R. E. McKinney, "Phosphate Removal by Lime-
Biological Treatment Scheme," J. Water Pollution Control Feder-
ation, Ul, (7), 1259 (1969).
20. Sawyer, C. N., "Biological Engineering in Sewage Treatment,"
Sewage Works J., l6_, (9), 925 (191*1*).
21. Sekikawa, Y., S. Nishikawa, M. Okazaki, and K. Kato, "Release
of Soluble Phosphates in the Activated Sludge Process," 3rd
International Conference on Water Pollution Research, Munich,
Germany, (Sept., 1966).
22. Hall, M. W., and K. Engelbrecht, "Uptake of Soluble Phosphate
by Activated Sludge; Parameters of Influence," Proceedings of
the 7th Industrial Water and Waste Water Conference, Univ. of
Texas, Austin, p.II,8, (1967).
80
-------
23. Borchardt, J. A., and H. S. Azad, "Biological Extraction of
Nutrients," J. Water Pollution Control Federation, hOt (10),
1739 (1968).
2U. Srinath, E. 0., C. A. Sastry, and S. C. Pillai, "Rapid Removal
of Phosphorus from Sewage by Activated Sludge," Experientia,
15_, 9 (1959).
25. Alarcon, G. 0., "Removal of Phosphorus from Sewage," Masters
Essay, The John Hopkins Univ., Baltimore, Maryland, (1961).
26. Feng, T. H., "Phosphorus and the Activated Sludge Process,"
Water and Sewage Works, 109. (ll), ^31 (1962).
27. Campbell, L. A., "The Role of Phosphate in the Activated Sludge
Process," Proceedings of the 21st Purdue Industrial Waste
Conference, (May, 1966).
28. Leary, R. D., and L. A. Ernest, "Industrial and Domestic Waste-
water Control in the Milwaukee Metropolitan District," J. Water
Pollution Control Federation, 3£, (7), 1223 (1967).
29. "Instructions For YSI Model 53 Biological Oxygen Monitor,"
Yellow Springs Instrument Co. Inc., Yellow Springs, Ohio.
30, "Instruction Manual Hach C R Surface Scatter Turbidimeters
Model 1889," Hach Chemical Company, Ames, Iowa.
31. "Instruction Manual Hach Laboratory Turbidimeter Model 2100,"
Hach Chemical Company, Ames, Iowa.
32. "Procedure Manual For Atomic Absorption Spectrophotometry,"
Instrumentation Laboratory Inc., Lexington, Mass.
33. "Standard Methods for the Examination of Water and Wastewater."
12th Ed. Araer. Pub. Health Assn., New York (1965).
31*. Goodman, B. L., and J. W. Foster, "Notes On Activated Sludge,"2nd
Edition, Smith and Loveless Division of Union Tank Car Company,
Lenexa, Kansas.
35. Kipp, R. J., "Statistical Analysis of Phosphate Removal Data
for 1968, 1969; Jones Island Sewage Treatment Plant, Milwaukee,
Wisconsin," Marquette Univ. (May 1970).
81
-------
36. "Official Methods of Analysis of the Association of Official
Agricultural Chemists." 10th Ed.t Assn. of Official Agricultural
Chemists, Washington, D.C.~Tl965).
37. Eckenfelder, Jr., W. W., and D. J. O'Connor/'Biological Waste
Treatment." Pergamon Press, New York, New York (1961).
38. Okun, D. A., and W. R. Lynn, "Preliminary Investigations into the
Effect of Oxygen Tension on Biological Sewage Treatment," in J,
McCabe and W. W. Eckenfelder Jr., "Biological Treatment of Sewage
and Industrial Wastes." Volume I, Rheinhold, New York, New York
(1956).
39. Ford, D. L., J. T. Young, and W. W. Eckenfelder Jr., "Dehydro-
genase Enzyme as a Parameter of Activated Sludge Activities,"
Proceedings of the 21st Ind. Waste Conf., Purdue Univ., Part I,
(May 3 to 5, 1966).
UO. Natrella, M. G., "Experimental Statistics",NBS Handbook No. 91,
U.S. Government Printing Office, Wash., B.C. (1963).
1*1. Jones, P.H., and D. Prasad, "The Use of Tetrazolium Salts as a
Measure of Sludge Activity," J. Water Pollution Control Feder-
ation, Ul, (11, Part 2), R UUl (1969).
U2. Gopalakrishna, E. M., J. Winters, and L. Gartz "Report on the
X-Ray Analysis of Sludge Material," Marquette, Univ. (June 1969).
U3. Natarajan, Dr., M. Seitz, J. Winters, and R. J. Riedner, "Sludge
X-Ray Analysis Report," Marquette Univ. (December 1969).
UU. Seitz, M. A., R. Riedner, and J. Winters, "X-Ray Diffraction
Studies of Sewage Sludge Residue," Marquette Univ. (March 1970).
U5. Chang, S. C., and M. L. Jackson, "Solubility Product of Iron
Phosphate," Soil Science of America Proceedings, 21. (3), 265
(1957).
U6. Galal-Grochev, H., and W. Stumm, "The Reaction of Ferric Iron
with Ortho-Phosphate," J. Inorg. Nucl, Chem., 2£, 576 (1963).
82
-------
SECTION IX
PHOSPHORUS NOMENCLATURE AND ABBREVIATION'S GLOSSARY
PHOSPHORUS NOMENCLATURE
1. Total Phosphorus (TP).
All the phosphorus present in sample (whether in the
soluble or insoluble state and present as ortho, poly,
organic, etc., phosphorus compounds) which is converted
by ternary acid digestion to soluble ortho-phosphate.
2. Soluble Ortho - Phosphate (SOP).
All phosphorus measured by direct colorimetric analysis
of sample filtrate. (Angel Reeve Glass Fiber Pad No.
93UAB).
3. Total Soluble Phosphorus (TSP).
All the phosphorus compounds in the sample filtrate
converted by ternary acid digestion to ortho-phosphate.
U. Suspended Solids Phosphorus (SS-P).
Represents the phosphorus present in the sample
suspended solids. (SS-P = TP - TSP).
ABBREVIATIONS GLOSSARY
1. BOD - five day biochemical oxygen demand.
2. BOI>R/TSPR - ratio of BOD removed/day to TSP removed/day.
3. CV - coefficient of variation (standard deviation
divided by the average, multiplied by 100).
U. CFM - cubic feet per minute.
5. COD - chemical oxygen demand.
6. DO - dissolved oxygen.
7. EP - East Plant.
8. EPML - East Plant mixed liquor.
9. EPRS - East Plant return sludge.
10. EPWS - East Plant waste sludge.
11. F/M - (Ratio of food to microorganisms) /Day.
83
-------
#BOD/DAY
#MLVSS in the Aeration Capacity
12. MGD - million gallons/day.
13* ML - mixed liquor.
lU. ML-DO - mixed liquor dissolved oxygen.
15. ML-SDI - mixed liquor sludge density index.
16. MLSS - mixed liquor suspended solids.
17. MLSS-0 - mixed liquor oxygen uptake rate.
mg 02/mg VSS/hour).
18. MLVSS - mixed liquor volatile suspended solids.
19. N - nitrogen.
20. P - phosphorus.
21. RS - return sludge.
22. RSSS - return sludge suspended solids.
23. SOP - soluble ortho-phosphate.
2k. SS - suspended solids.
25. TP - total phosphorus.
26. TSP - total soluble phosphorus
27. TP/M - (ratio of total phosphorus to Microorganisms)/Day.
dTP/DAY
#MLVSS in the Aeration Capacity
28. ^IM TPF/5 mis of ML - micro-moles of triphenylformazin/
5mls of mixed liquor.
29. VSS - volatile suspended solids.
30. WP - West Plant.
31. WS - waste sludge.
-------
SECTION X
APPENDIX A
PHOSPHORUS DETERMINATION WITH TECHNICON AUTOANALYZER
Sample Preparation
A. Total Phosphorus
1. Pipette unfiltered sample into a 100 ml. volumetric
flask (20 mla effluent, 5 mis for sevage).
2. Add 5 mis of Ternary Acid Mixture and 3 glass beads.
3. Heat on hot plate to dense fumes of perchloric acid,
plus 5 minutes, cool.
U. Add 20 mis of distilled water, bring to a boil, boil
5 minutes, cool.
5. Add 1 drop of phenolphthalein^neutralize with 10 NaOH
to a faint pink color.
6. Just discharge pink color with INH^SOij, dilute to
100 ml, mix.
7. Place solution from step 6 in the sampling cup of
the autoanalyzer.
8. Obtain the phosphorus concentration of the sample
from the standard curve.
B. Total Soluble Phosphorus
1. Same as total phosphorus, except the aliquot is
filtered through an Angel Reeves glass fiber pad
93UAH.
C. Soluble Ortho-Phosphate
1. Filter through Angel Reeves glass fiber pad
2. Dilute filtrate if needed.
3 Place in sampling cup of the autoanalyzer.
85
-------
Reagents
A. Ammonium Molybdate - Dissolve 200 gm of (HH^)/- MO.,
in 10 liters of distilled water. Add 1680 ml of c
and dilute to 20 liters.
B. ANSA Stock Solution - Dissolve 219 gm Na2S20,- and 8 gm
SO- in 700 ml of distilled water (temperature <50° C), add
U gm of 1-amino- 2-naphthol -U- sulfonic acid. Dilute to
2 liters. For daily use, prepare a 1:10 dilution.
C. Phosphorus Standard Curve use standards, both digested and
undigested from 0.1 to 1.2 mg/L-P in increments of
0.1 mg/L-P from a 1000 mg/L-P stock (U.386 gm of
oven dried at 103°C for U hours, in one liter).
D. Ternary Acid Mixture - Add 100 mis of 96% HpSOj^ to 500 mis
of 10% HN03, mix. Add 200 mis 70$ HClOj^, mix and cool.
-------
00
SAMPLER _S_
RATE:iP_pERHR.
1:2 CAM
WATER RINSE EVERY
4** SAMPLE
^ TO WELL
O
TUBE SIZE
(INCHES)
0.090 WATER
0.073 ANSA
0.045 AIR
/^y0.056 SAMPLE
0.073 MOLYBDATE
FIGURE 19 TECHNICON AUTOANALYZER SCHEMATIC
-------
APPENDIX B
PROCEDURE USED FOR MLSS AND RSSS DETERMINATION:
A. Determination of SS concentration by weight.
1. Mix sample well, pour (100 mis for ML., 50 mis for RS)
into a 100 ml graduate cylinder.
2. Add 5# chlorhydrol solution (6 drops for ML and 12
drops for RS) mix 3 times by inversion, let sit for
5 minutes.
3. Filter under vacuum thru tared filter paper (9cm, S and
S Sharkskin for ML, Whatman No. 3 for RSJ placed on a
buechner funnel.
U. Dry the paper for 1 hour at 103° C in a Forced
Draft Oven.
5. Cool it for 5 minutes in a dessicator and weigh back.
6. For MLSS subtract from this weight the tare weight of
the paper. This gives solids in units of grams which
in turn is equivalent to per cent by weight. (For
RSSS since we used 50 ml sample, therefore multiply
the above weight by a factor of two to get per cent
RSSS by weight).
B. Determination of MLVSS
1. Place the filter paper with MLSS (use low ash S and S
filter paper) after step 5 in a previously ashed and
tared silica dish, and then ash for 15 minutes at 600°C.
2. Cool for 30 minutes in a dessicator and then weigh back.
3. The MLSS less the MLSS ash divided by the MLSS when
multiplied by 100 equals per cent MLVSS.
88
-------
APPENDIX C
BOD DETERMINATION
Dilution Water
1. Add 1 ml of the following solutions (33) to each liter of aged
distilled water, 5 or more days.
Phosphate Buffer Solution
Magnesium Sulfate Solution
Calcium Chloride Solution
Ferric Chloride Solution
2. Aerate this mixture for 5 minutes.
Meter Setting
1. Place probe in aerating distilled water for 5 minutes.
2. Check zero and adjust if necessary.
3. Check red line and adjust if necessary.
U. Determine barometric pressure.
5. Read temperature on meter.
6. Determine DO setting with pressure-temperature chart.
7. Adjust calibration for DO of the day.
Procedure
1. Discharge stale water in buffer line.
2. Siphon dilution water into BOD bottle for blank.
3. Place probe in BOD bottle and read DO when meter stabilizes.
h. Stopper with rubber seal and incubate for 5 days, dilution
water blank.
5. Determine dilutions to be made (set of 2) for samples.
6. Siphon dilution water to cylinder, filling to required mark.
7. Add sample desired with pipette or siphon.
8. Mix well with plunger and siphon to BOD bottles.
9. Determine DO, stopper and seal, and incubate 5 days.
10. After 5 days remove from incubation and determine DO as before,
89
-------
Calculations
1.
2.
Initial DO - 5 day
Conversion factors
5 day BOD, dividing
x dilution factor = 5
of U and 6 day sevage
by appropriate factor
U day
Sewage .875
Effluent .796
parts
Sample
1
1
1
1
1
1
1
1
parts
dilution HgO
+ 1
+ 3
+ 9
* 19
+ 39
+ U9
+ 79
+ 99
DILUTION TABLE
ml
dilution H
150 ml
225 "
270 "
285
292.5 "
29U
296.25 "
297 "
day BOD
and effluent B01
listed below.
6 day
1.076
1.231
add ml
20 of Sample
150 ml
75
30
15
7.5 "
6
3.75 "
3
90
-------
APPENDIX D
DISCUSSION OF MATERIAL FOUND FLOATING ON THE SURFACE OF THE EP AERATION
TANKS AND THE AEROBIC DIGESTION OF WASTE SLUDGE.
The principal microorganism found in this material floating
on the surface of the E.P. aeration tanks vas identified as belonging
to Actinomycetaceae and to the Genus Nocardia. A sample of this
material was found to contain 85$ volatile matter and 31$ hexane solu-
ble materials. Regular defoaming agents as mentioned before were
ineffective in breaking this foam. Vacuum skimming of aeration tanks
and clarifier feed channels reduced the amount of foam and aided in
overcoming this problem. This floating material did not appear during
all this time in the WP.
The effect of extended aeration on the stability of the
Actinomycetaceae foam was also investigated. The East Plant Reserve
Return Sludge channel was filled with approximately 286,000 gallons
of waste sludge. This waste sludge was vigorously aerated for 21 days
(3-25-69 to U-15-69). The air application rate could not be defined
because the air supply to this RS channel was not metered. At no
time during this lengthy aeration period was a decrease in the
quantity or the density of the Actinomycetaeeae foam observed.
During this study it was also decided to observe the effect
of extended aeration on the aerobic digestion of the waste sludge
containing this floating matter. Seven liter composite samples were
taken out of the aerated sludge for several days during this experiment
and analyzed for TP,TSP, SOP, SS, VSS, pH and total Nitrogen. The
results of these analyses are presented in Table 25. Some of the
variation in the data was caused by sampling and analytical errors.
Further, a part of the reduction of SS and TP in the aerated waste
sludge was due to the dilution caused by some waste water entering
the reserve RS channel.
The following general observations were made regarding the
aerobic digestion of sludge in the reserve RS channel.
1. There appeared to be an acclimatization period of approxi-
mately 2 to 3 days before the aerobic digestion of the
solids began.
2. After the acclimatization period, aerobic digestion of the
sludge solids was significant as indicated by a sudden
increase in the soluble phosphorus and a decrease in the
$VSS and % nitrogen in the waste sludge solids.
91
-------
TABLE 25
AEROBIC DIGESTION OF SLUDGE
Date
-25
3-27
3-28
3-31
l*-2
U-3
U-7
U-9
U-ll
U-lU
1*-15
Day
Tu
Th
F
M
W
Th
M
W
F
M
Tu
*
0
2
3
6
8
9
13
15
17
20
21
Phosphorus
mff/L-P
TP
280
270
266
- 2U6
258
238
226
239
220
205
TSP
2.1*
3.1*
-
25.1*
32.8
U8.6
51.6
58.3
56.0
53.1
SOP
2.1
2.8
11*. 6
1U.7
32.5
U6.9
1*9.1
53.1*
53.6
52.9
Sludge
Solids
PH
%
MG/L VSS
10
9
8
7
7
5
6
5
5
1*
,000
,1*30
,31*0
,890
,180
,910
,300
,560
,010
,350
61*. 5
63.8
56.6
59.3
56.1*
55.3
56.2
55.7
53.5
_
7.
7.
7.
7.
7.
7.
7.
7.
7.
_
%m
in
Sludge
(Dry)
1 6.61*
3 -
2 6.70
0 -
1 5.95
1 5.86
0 -
0 6.05
1 -
5.90
%P
in
Sludge
(Dry)
2.78
2.83
3.13
2.80
3.H*
3.20
2.78
3.25
3.27
3.1*9
"Number of days aerated.
92
-------
3. a period of 6 to 8 days over k5% of the volatile
-dtter in the waste sludge solids was reduced and
after that the % reduction of volatile matter did
not increase significantly.
1*. During aerobic digestion of sludge solids, the solids
appeared to hold the remaining phosphorus very strongly.
This was shown by the increase in the % phosphorus in
the solids on a dry basis as the digestion progressed.
5. Aerobic digestion of sludge solids had no effect on the
pH value of the sludge.
It was observed that similar floating material started to
reappear in November (1969) in small quantitites and on limited
occasions in both plants when no changes in loading or other process
parameters were made. This foam then continued to build up to the
extent where it started affecting the operation of both the plants.
The cause or causes of the appearance of this floating material
and the controlling of this material by process parameters changes
is not yet fully known but we did seem to have limited success in
overcoming this floating material by increasing F/M loadings.
93
-------
APPENDIX E
AVERAGE DAILY SCREENED SEWAGE CHARACTERISTICS AND PLANT OPERATION DATA
1967
SCREENED SEWAGE CHARACTERISTICS
Flow mgd
BOD mg/L
SS mg/L
TP mg/L
TSP mg/L
SOP mg/L
% of TP in SS
PLANT OPERATION
Flow
BOD
SS
TP
TSP
SOP
mgd
mg/L
mg/L
mg/L
mg/L
mg/L
DETENTION TIME UNDER AIR HOURS
Air Applied Cu. ft
Food /Mi c r oorgani sm
MLSS
% RS
Lbs. BOD
MG/L
./gal. Sewage
Ratio
per 1000 cu. ft. of
183.
297
30U
8.
WEST
7U.
15.
22
1.
___
—
6.
l.
0.
2800
28.
58.
5
1
2
8
1*0
1*25
0
1
,1*
,1*
EAST
109.0
18.2
25
1.3
___
—
6.6
1.22
O.U53
2700
25.U
60.2
WEST
•^•^•^•B
76.
26.
1*7
2.
—
0.
6.
1.
0.
2900
28.
59.
1968
183.U
306
31U
9.6
2.8
3
8
2
87
8
37
1*25
2
1+
1969
181.6
239
227
8.U
3.5
2.3
57.2
EAST
107.
19.
30
1.
—
0.
6.
1.
0.
2800
25.
60.
2
2
7
83
8
21
1*1*0
1*
5
WEST
76.U
21.3
1*1
2.0
0.99
0.86
6.6
1.36
0.391
2600
27.5
1*7.8
EAST
105.2
1U.8
23
1.1*
0.86
0.73
6.8
1.20
0.388
2600
25. U
U7.5
Aeration Tank Capacity
-------
APPENDIX P
TOTAL PHOSPHORUS REMOVAL AT THE JONES ISLAND PLANTS BASED ON PLANT FLOWS
The values used in the calculations are yearly averages.
VO
Flov MOD
TP mg/L-P
TP pounds
.ant Effluent
Flow MOD
TP mg/L-P
TP pounds
>tal TP pounds
Removal
183 .U
8.U
12.8U8
W E
7U.5 109.0
1.2 1.3
7U6 1182
1928
85.0
183. U
9.6
1U.68U
W E
76.0 107.2
2.2 1.7
1^00 1520
2920
80.1
181.6
8.U
12,722
W E
76. k 105.2
2.0 l.U
1271* 1228
2502
80.3
W = West Plant
E = East Plant
7350
81.7
-------
1
Access/on Number
w
5
ry Subject Field &, Group
05
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
Organization
Rouai*acra PrnmH ao< nn nf 4-Via ("S-ftr «-f M-i 1 uonlraa
Milwaukee, Wisconsin
Title
Phosphorus Removal By An Activated Sludge Plant
10
Authors)
Leary, R. D.
Ernest, L. A.
Powell, R. S.
Docta, L. H.
Malhotra, S. K.
Kipp, R. J.
j£ Project Designation Program #3.70]
Grant # WPD 188-01-67,
21 Note
LO DXD
188-02-68, 188-03-69
22
Citation
Water Resources Research Catalog.
Vol. 3, Dec. 196T, p 585, Abstract 5.1362
23
Descriptors (Starred First)
•Phosphorus removal, *Activated Sludge Process,
Process parameters, Wastewater treatment,
•Biological treatment.
25
Identifiers (Starred First)
27
Absttact
The overall total phosphorus removal in conventional activated sludge treatment plants
at Jones Island, Milwaukee, Wisconsin, averages 80$ as opposed to less than 50$ in the
majority of the activated sludge plants elsewhere in this country. A detailed plant-
scale evaluation of the activated sludge process parameters was made over a period of
three years to obtain optimum values for phosphorus removal. The total phosphorus re-
moval generally followed the variations of the flow and BOD of the plant influent and
was not dependent on the clarifier sludge blanket-depths. The BOD and the total phospho-
rus loading rate on the microorganisms and the MLSS concentrations were found to be of
some significance in the removal of phosphorus. Total phosphorus removal was directly
related to the solids (Milorganite) production. A significant portion of the phosphorus
is insolubulized in the wastewater befoiteit reaches the plant. It is proposed that this
is a probable cause for the higher total phosphorus removals obtained. It appears that
brewery waste water aids soluble phosphorus removal at the Milwaukee plants. Limited
studies with waste pickle liquor addition to the ML indicated that consistently higher
soluble phosphorus removals can be obtained without any apparent detrimental effect on
the process or equipment.
Abstractor
S.K.fc R..T.
Institution
Marquette University, Milwaukee, Wisconsin
WR:102 (REV. JULY 1969)
WRSIC
SEND. WITH COPY OF DOCUMENT. TO: WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON. D. C. 20240
* SPO: I 870-389-930
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