EPA-670/2-75-019
April 1975
Environmental Protection Technology Series
BIOLOGICAL TREATMENT OF
COMBINED SEWER OVERFLOW AT
KENOSHA, WISCONSIN
National Environmental Research Center
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
-------
EPA-670/2-75-019
April 1975
BIOLOGICAL TREATMENT OF
COMBINED SEWER OVERFLOW AT
KENOSHA, WISCONSIN
By
Robert W. Agnew, Charles A. Hansen, Michael J. Clark
Envirex Inc.
Milwaukee, Wisconsin 53214
0. Fred Nelson
City of Kenosha
Kenosha, Wisconsin 531^0
William H. Richardson
Alvord, Burdick and Howson
Chicago, Illinois 60606
Project No. 11023 EKC
Program Element No. 1BB034
Project Officer
Clifford J. Risley, Jr.
U.S. Environmental Protection Agency
Region V
Chicago, Illinois 60604
NATIONAL ENVIRONMENTAL RESEARCH CENTER
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO ^5268
-------
REVIEW NOTICE
The National Environmental Research Center-Cincinnati has reviewed this
report and approved its publication. Approval does not,signify that
the contents necessarily reflect the views and policies of the U.S.
Environmental Protection Agency, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.
i i
-------
FOREWORD
Man and his environment must be protected from the adverse effects of
pesticides, radiation, noise and other forms of pollution, and .the
unwise management of solid waste. Efforts to protect the environment
require a focus that recognizes the interplay between the components
of our physical environment--air, water, and land. The National
Environmental Research Centers provide this multidiscipiinary focus
through programs engaged in
o studies on the effects of environmental contaminants
on man and the biosphere, and
o a search for ways to prevent contamination and to
recycle valuable resources.
This report portrays an effective alternative for control of storm
flow pollution by modification of an existing biological treatment
process.
A. W. Breidenbach, Ph.D.
Di rector
National Environmental
Research Center, Cincinnati
i .1
-------
ABSTRACT
This report describes the design, construction, operation and two year
evaluation of a biological process used for the treatment of potential
combined sewer overflow. The project was conducted in the City of
Kenosha, Wisconsin. A 75.700 cu m/day (20 mgd) modified contact stabili-
zation process was constructed on the grounds of the city's existing
87,055 cu m/day (23 mgd) conventional activated sludge plant at a total
cost of 1.1 million dollars.
The demonstration system consisted of pumping facilities, the conversion
of an unused flocculation basin into a grit basin, construction of a
•contact tank and stabilization tank, installation of a final clarifier and
all associated yard piping and automatic control equipment. The demonstra-
tion system's raw sewage pump and clarifier were used by the dry weather
plant when the demonstration system was not in use. The chlorination and
sludge handling facilities of the dry weather plant were utilized by the
demonstration system.
Results from the evaluation program proved the demonstration system to
be a feasible concept for the treatment of potential combined sewer
overflow. The system was operated and evaluated during ^9 runs in which
681,300 cu m (180,000,000 gal.) of potential overflow was treated. Based
on these tests, expected removal efficiencies for suspended solids, BOO,
and TOC are 30%, 85$, and 76%, respectively. The optimum ranges for
operation of the various process variables were also determined.
Operating costs for running the system 300 hours per year are estimated
at 3.567{/cu m (I3.5C/1000 gal.). An additional benefit derived from
the demonstration system was improved removal efficiencies by the dry
weather plant through utilization of the demonstration system facilities.
This report was submitted in fulfillment of Project No. 11023 EKC under
the partial sponsorship of the U.S. Environmental Protection Agency. The
study program associated with this project was performed by Envirex Inc.
acting as a subcontractor to the grantee, the City of Kenosha. Work
was completed as of November 1973*
IV
-------
CONTENTS
Abstract fv
List of Figures vl i
List of Tables x
Acknowledgments x!
Sections
I CONCLUSIONS 1
II RECOMMENDATIONS 4
III INTRODUCTION 5
IV EXISTING TREATMENT FACILITIES AND SEWERAGE SYSTEM 7
Water Pollution Control Plant 7
Sewerage System 8
V SYSTEM DESIGN AND CONSTRUCTION 12
Contact Stabilization Process Theory 12
Contact Stabilization Operating Experience 16
System Design for Kenosha 17
Pumping Plant 19
Grit Tank '9
Contact Tank 19
Stabilization Tank 22
Sludge Transfer Pumps 28
Oxygen Requirements 28
Final Clarifier Equipment 30
Instrumentation and Control 30
System Deployment 3**
Construction Costs and Timing 36
VI OVERFLOW QUALITY STUDY 39
Instrumentation 39
Monitoring Procedure M
Precipitation Data *»5
Overflow Quality Analysis ^8
-------
CONTENTS (continued)
Section
VII EVALUATION PROGRAM AND RESULTS 5»
Plan of Operation 5^
Method of Operation 56
Feasibility Study 60
Study of Process Variables 63
Optimum Treatment Conditions 66
Relationship to Dry Weather Plant 69
Ancillary Studies 71*
BOD:COD:TOC Relationships 7*»
Time Series Analyses 77
Economic Considerations 77
Operating Costs 77
Total Costs 80
Overflow Volumes 82
VIM STABILIZATION TANK SLUDGE STUDIES 88
Sludge Behavior Under Static Conditions 88
Continuous Flow Through the Stabilization Tank 91
Bench Scale Studies 98
IX FUTURE DESIGN CONSIDERATIONS 110
X REFERENCES 113
XI PUBLICATIONS 116
XII GLOSSARY 117
XIII APPENDICES 118
A. Description of Analytical Techniques ]]8
B. Overflow Quality Data 1970 121
C. Demonstration System Operating Data 1^6
D. Procedure for Sludge Studies
v i
-------
FIGURES
No. Page
1 Map of Kenosha Indicating Combined Sewer Area 9
2 Illustration Showing Interceptor Sewer and Combined
Sewer Overflow Discharge Locations '0
3 Typical Kenosha Overflow Mechanism 11
k Schematic Diagram of Contact Stabilization Process 13
5 View of Gas Driven Pump Engine 20
6 New Gas Driven Engine and Pump Shown in Relation to
Existing Pumping Facilities 20
7 View of Grit Tank From Influent End 21
8 View of Larger Compartment of Contact Tank 23
9 Contact Time Versus Various Flow Rates 2k
10 View of One Stabilization Tank Compartment While Empty 25
11 View of Full Stabilization Tank From Platform Between
Stabilization and Contact Tanks 2^
12 Stabilization Tank Depth Versus Reaeration Time at
Various Flows 27
13 Plan and Elevation Views of Stabilization Tank and
Contact Tank 29
14 Overall View of Final Clarifier 31
15 Detailed View of Clarifier Showing Scum Baffle, Effluent
Trough, Deflector Skirt, and Feed Trough 31
16 View of Demonstration System Control Panel 32
17 Plan View of Kenosha Water Pollution Control Plant 35
18 Aerial View of Kenosha WPCP Depicting Demonstration
System Facilities 38
19 Map of Kenosha Showing Raingauge Locations ^0
v i i
-------
FIGURES (continued)
No. Page
20 Exterior View of Overflow Monitoring Station **2
21 Interior View of Monitoring Station Showing Sampling
and Flow Recording Instrumentation ^2
22 Schematic Drawing of a Typical Monitoring Site ^3
23 Histogram of Rainfalls in Kenosha for June 1, 1970
to October I1*, 1970 *»7
2k View into Typical Sampler Constructed for Use in
Conjunction with the Demonstration System 58
25 Raw and Final Sample Quality Variance with Time 78
26 Raw and Effluent Sample Quality Variance Through the
Dry Weather Plant Primary Sedimentation Tanks During
Run No. ^7. 79
27 Estimated Demonstration System Operating Costs Versus
Hours of Operation 81
28 Percentage of Overflow Treated Versus Rainfall Amounts
for 28 Events 83
29 Rainfall, 67th Street Overflow Level and Demonstration
System Flow Rate Versus Time for Run No. 9 86
30 Oxygen Uptake Rate and Sludge Temperature Versus
Sludge Age for August 18, 1972 to September 11, 1972 90
31 SS, VSS, and Percent Volatile Solids Versus Sludge
Age for August 18, 1972 to September 11, 1972 90
32 Calculated Surface Overflow Rate Versus Sludge Age for
August 18, 1972 to September 11, 1972 90
33 Stabilization Tank Sludge SS, VSS, and Percent Volatile
Solids, and DWP WAS SS Versus Days of Continuous Flow
for July 9, 1973 to July 20, 1973 95
34 Oxygen Uptake Rate per Gram of Volatile Suspended
Solids Versus Days of Continuous Flow for July 9,
1973 to July 20, 1973 96
VIM
-------
FIGURES (continued)
No- Page
35 Supernatant SS Concentration Versus Days of Continuous
Flow for July 9, 1973 to July 20, 1973 96
36 Calculated Surface Overflow Rate Versus Days of Continuous
Flow for July 9, 1973 to July 20, 1973 96
37 Calculated Sludge Volume Index Versus Days of Continuous
Flow for July 9, 1973 to July 20, 1973 96
38 SS, VSS, Total COD, and Total Alkalinity Concentrations
Versus Sludge Age for Bench Scale Tests, July 11, 1973
to July 31, 1973 102
39 SS, VSS, Total COD and Total Alkalinity Concentrations
Versus Sludge Age for Bench Scale Tests, August 8, 1973
to August 23, 1973 1°3
40 SS, VSS, Total COD, and Total Alkalinity Concentrations
Versus Sludge Age for Bench Scale Tests, August 28,
1973 to September 19, 1973 104
41 Oxygen Uptake Rate Per Gram of Volatile Suspended Solids
Versus Sludge Age for Bench Scale Tests, July 11, 1973
to July 31, 1973 107
42 Oxygen Uptake Rate Per Gram of Volatile Suspended Solids
Versus Sludge Age for Bench Scale Tests, August 8,
1973 to August 23, 1973 107
43 Oxygen Uptake Rate Per Gram of Volatile Suspended Solids
Versus Sludge Age for Bench Scale Tests, Augsut 28, 1973
to September 19, 1973 107
44 Flotation Test Percent Float Solids and Effluent SS Versus
Sludge Age for July 11, 1973 to July 31, 1973 108
45 Effluent SS and Percent Float Solids Versus Sludge Age
for Bench Scale Tests, August 8, 1973 to August 23, 1973 108
46 Flotation Test Percent Float Solids and Effluent SS Versus
Sludge Age for August 28, 1973 to September 19, 1973 108
i x
-------
TABLES
No.
1 Breakdown of Construction Costs 37
2 Kenosha Rainfall Summary for 1970 46
3 Kenosha Overflow Quality Summary for 1970 49
4 Sampling Points and Analyses Performed 55
5 Ranges of Operation, Runs No. 1-19 61
6 Operating Results, First 19 Runs 62
7 Results of Step Wise Regression Analysis 67
8 Operating Values for Satisfactory Performance 68
9 Performance for 30 Runs at Acceptable Operating Levels 70
10 Effect of Demonstration System Clarifier on Kenosha 71
WPCP Performance
11 Mean and Standard Deviations for BOD/COD, BOD/TOC,
and COD/TOC Ratios 75
12 Overflow Quantity Data from 1972 and 1973 84
13 Measured Parameters for Stabilization Tank Sludge
July 9 to July 20, 1973 94
14 Aerobic Digestion and Flotation Results, July 11 99
to July 31, 1973
15 Aerobic Digestion and Flotation Results
August 8 to August 23, 1973 1Q0
16 Aerobic Digestion and Flotation Results
August 28 to September 19, 1973 )01
B1-B25 Overflow Qual ity 1970 I21-14r
C1-C49 Operating Data for Runs No. 1-49 146-242
-------
ACKNOWLEDGMENTS
The authors would like to express their sincere appreciation to the
U.S. Environmental Protection Agency, the State of Wisconsin, and the
City of Kenosha for their financial support of this project. The
special efforts of the Mayor of the City of Kenosha, Wallace C. Burkee,
and the entire Board of Water Commissioners, chaired by Peter P.
Nedweski, made this project a reality.
The assistance rendered by Clifford Risley, Jr., Project Officer, and
Richard Field, Chief Storm and Combined Sewer Section, USEPA was
received with much gratitude. Operation of the demonstration system over
the two year test period was primarily performed by Robert W. Agnew,
Charles A. Hansen., and MJchaeK J. Clark of Env!rex. All laboratory
analyses were performed with noteworthy professional proficiency,
regardless of logistic circumstances, by the Envirex Analytical Labora-
tory directed by Richard E. Wultschleger.
The encouragement-and'support supplied by the General Manager of the
Kenosha Water Utility, .0. Fred Nelson, and the assistance of the
Kenosha Water Pollution Control Plant Superintendent, Frank I. Vllen
(retired) and Gerald G. Selin were vital to project performance.
Finally, thanks are given to the staff and operators of the Kenosha
Water Pollution Control Plant who allowed their treatment plant to perform
as a field laboratory for two years and who made the greatest contribution
to the success of the project through their assistance and understanding.
x i
-------
SECTION I - CONCLUSIONS
'• A 75,700 cu m/day (20 mgd) modified contact stabilization process
for the treatment of potential combined sewer overflow was designed
and constructed on the grounds of the 87,055 cu m/day (23 mgd)
Kenosha Water Pollution Control Plant at a total cost of
$1,178,779-11, including engineering,
2. Prior to operation of the demonstration system, a study of the
overflow quality from Kenosha's three combined sewer overflows
and from the raw flow to the Water Pollution Control Plant during
periods of overflow was performed. The results of this study
indicated that these discharges were of higher contaminant concen-
tration than dry weather sewage, there was great variance in
contaminant concentrations at the four sampling locations, and
the high percentage of oxygen demanding materials in the particulate
form would be advantageous to demonstration system efficiency.
3. The feasibility of the demonstration system was verified by the
first nineteen uses of the system during which 277,062 cu m
(73,200,000 gal.) of potential overflow was treated. The removals
achieved during these runs, based upon weighted mean concentrations,
were 33% suspended solids, 83% BOD, and 812 TOC.
4. Eighteen test runs were carried out to determine the optimum
ranges of demonstration system operation for various process
variables. These ranges were found to be:
MLSS Concentration >2,100 mg/1
Reaeration Time 1-4 hours
Stabilization Time 10 minutes
5. Thirty of the 49 total system runs were found to fall within the
optimum ranges of operation. These 30 runs, treating 403,103 cu m
(106,500,000 gal.), had arithmetic mean percentage removals of
90.4% suspended solids, 84.8£ BOD, and 76.5S TOC. Arithmetic
mean effluent quality for these runs was 23 mg/1 suspended solids,
16 mg/1 BOD, and 23 mg/1 TOC.
-------
6. The dry weather treatment plant efficiency was improved by
utilization of the demonstration system final clarifier during
periods when the demonstration system was not in use. Dry weather
plant removal percentages Increased from 82 to 3k% and 64 to 88$,
for BOD and suspended solids, respectively, after the demonstration
system was installed.
7. Operating costs, including pumping, chlorination, sludge disposal,
aeration, and labor, are estimated to be 3.567
-------
treatment system. This Is a direct result of the potential overflow
treatment system utilizing the waste activated sludge generated by
the adjoining dry weather treatment plant.
11. Operation of the system during winter months was not attempted
because of anticipated problems of ice buildup and possible sinking
of the surface aerators. Fixed air disperser systems would probably
be more applicable in future systems.
12. The method of manually cleaning the grit basin should be replaced
by a mechanical process.
-------
SECTION II - RECOMMENDATIONS
It is recommended that:
I. The modification of the contact stabilization process used in the
Kenosha demonstration project be recognized by the federal and
state governments as a feasible alternative to sewer separation
and be used in future applications for the treatment of potential
combined sewer overflows in locations having an adequate sewage
conveyance system and an existing dry weather biological treatment
process.
2. The City of Kenosha make modifications to its existing overflow
regulator mechanisms to reduce the amount of overflow at the
beginning of a rainfall, and that the demonstration system be
put into operation in anticipation of rainfall events. The
remaining amount of overflow stil! occurring under this mode of
operation should then be determined, and the required amount of
storage/treatment still needed to completely abate combined sewer
overflow in Kenosha be implemented,
3. An engineering investigation should then be performed to give a
detailed cost comparison of complete abatement of combined sewer
overflow in Kenosha by sewer separation as opposed to the cost
of integrating storage and the demonstration system for complete
abatement.
k. This method of treating potential combined sewer overflow be used
in series with in-line and off-line storage schemes, developed
under previous US EPA demonstration projects, to develop an
optimum scheme of treating combined sewer overflow,
5. A demonstration project be performed testing the feasibility of
converting a conventional activated sludge plant to the contact
stabilization mode during periods of high flow. It is anticipated
that, using common facilities, it would be possible to have a
high flow or wet weather capacity between 5 and 10 times the dry
weather flow rate.
6. A pilot scale study be conducted testing the effectiveness of
dissolved-air flotation for mixed liquor clarification utilizing
the mixed liquor from the contact tank of the demonstration system.
-------
SECTION II I - INTRODUCTION
The City of Kenosha, Wisconsin is an industrial city located in the south-
eastern corner of the state on the shores of Lake Michigan, midway
between Milwaukee, Wisconsin and Chicago, Illinois. It is the fifth
largest city in Wisconsin with a population of over 80,000. The City
encompasses an area of 37.32 sq km (14.41 sq mi) with the sewerage
system serving 33-51 sq km (12.94 sq mi). During the course of this
project 5.38 sq km (2.08 sq mi) of the City's sewerage system were
served by combined sewers. This area encompassed the heart of the
City's residential, commercial, and industrial activities.
During the 1960's, Kenosha had been undergoing a sewer separation
program. Based upon a private consulting engineering firm's report in
1966, it was estimated that it would cost the City 13.8 million dollars
to separate the remaining 5.39 sq km (2.08 sq mi) of combined sewers
(1). A portion of this sewer separation was required to provide for
local flooding and sewer relief from overloading regardless of the method
implemented for treatment of the combined sewer overflow. In 1968 the
State of Wisconsin Department of Natural Resources ordered the City to
begin a program for separation or control of pollution from combined
sewers, with completion of control facilities by July 1977 (2).
Faced with both the expense and public nuisance of separating the
combined sewers in question, the City chose to determine if there was
an alternative to separation which would effectively treat the combined
sewer overflow and have a cost equal to or less than that of separation.
The City's decision to look at an alternative to separation was
facilitated by the fact that if separation were completed, the storm
sewer discharges still would empty into Lake Michigan at locations which
are used as the City's beaches and lakefront recreational areas. It
was feared that the discharge from the storm sewers would still
necessitate treatment. Also, the existing interceptor sewer leading to
the Kenosha Water Pollution Control Plant (WPCP) had the capacity to
carry over 2.5 times the average dry weather flow. Since the existing
WPCP was operating at near design capacity, the idea of locating a
treatment process on the grounds of the WPCP to treat the excess wet
weather flows appeared most feasible.
As a result, the City of Kenosha together with the Environmental Sciences
Division of Envirex Inc. developed a proposal to demonstrate the
effectiveness of using a modification of the contact stabilization
-------
process to treat the combined sewer overflow. The proposal called for
the construction of a 75,700 cu m/day (20 mgd) contact stabilization
process on the grounds of the existing WPCP which was a 87,055 cu m/day
(23 mgd) conventional activated sludge plant.
The demonstration process would be operated for almost two years during
which time it would be determined if this method of treating potential
combined sewer overflow was feasible; what the optimum operating conditions
would be; and what effect a system of this size would have on reducing the
amount of combined sewer overflow. The proposal was approved and funded
by the US EPA under grant No. 11023 EKC in September of 1969. The funding
for the project, with an approximate total cost of $1,327,500.00, including
engineering, construction, and evaluation, was 62.9% US EPA, 22.2% State
of Wisconsin, and ]k.3% City of Kenosha.
The engineering firm of Alvord, Burdick and Howson of Chicago, Illinois
was retained by the City of Kenosha and in September of 1969 design of
the system began. From this date through November of 1971 the system
was designed, constructed and put through a mechanical shakedown period.
The system stood idle during the winter of 1971-1972 and was first put
into operation on April 12, 1972. Evaluation of the demonstration system
continued until October 1, 1973, except for the 1972-1973 winter period
when the system was shut down.
-------
SECTION IV - EXISTING TREATMENT FACILITIES AND SEWERAGE SYSTEM
WATER POLLUTION CONTROL PLANT
The Kenosha WPCP is located In the southeastern corner of the City,
bordered on the north and west by high income residential areas, on the
south by vacant land, and on the east by Lake Michigan. Prior to the
construction of facilities for the demonstration project, the WPCP
utilized primary sedimentation, having a maximum design capacity of
113,500 cu m/day (30 mgd), followed by a 87,055 cu m/day (23 mgd)
conventional activated sludge process and chlorination capable of
handling the maximum dry weather flow. Raw sewage enters the WPCP by
gravity from a 183 cm (72 in.) diameter interceptor sewer. Flow rates
in excess of the WPCP capacity are diverted by means of a hydraulic
control gate located at the termination of the interceptor in the WPCP
wet well facility. Closing of this gate decreases the flow to the WPCP
and causes the interceptor to surcharge and overflow (discussed later).
The raw sewage entering the WPCP passes through three comminutors before
entering a wet well. From the wet well the sewage is pumped to grit
removal facilities by pumps having a total capacity of 189,250 cu m/day
(50 mgd). The grit removal facilities consist of two tanks in parallel
having a total capacity of 151,^*00 cu m/day (40 mgd). Discharge from
the grit tank flows by gravity to the primary sedimentation facilities
consisting of 6 rectangular tanks having a total surface area of 2,303
sq m (2^,760 sq ft) and a volume of 7,213 cu m (257,600 cu ft). The
maximum hydraulic capacity of the primary sedimentation facilities is
rated at 113,550 cu m/day (30 mgd), resulting in surface overflow rates
(SOR) of *»9.7 cu m/day/sq m (1,212 gpd/sq ft) and a detention time of
1.5^ hours.
Effluent from primary sedimentation is conveyed to the mixed liquor
aeration tanks where it is mixed with return activated sludge (RAS).
There are four mixed liquor tanks having a total volume of 13,328 cu m
(^76,000 cu ft) and utilizing a fixed air disperser system. The aeration
time in these tanks is 3-72 hours at a maximum design capacity of 87,055
cu m/day (23 mgd). The mixed liquor from the aeration tanks flows to
three 25.9 m (85 ft) diameter final clarifiers, having a total surface
area of 1,581 sq m (17,020 sq ft). At a flow rate of 87,055 cu m/day
(23 mgd) the surface overflow rate is 55.1 cu m/day/sq m (1,350 gpd/
sq ft) and the detention time (not including RAS) is 1.32 hours. The
waste activated sludge (WAS) from the final clarifiers is thickened by
means of two dissolved air flotation units having a total capacity of
-------
8,080 kg (20,000 Ibs) of solids per day. The thickened WAS and primary
sludge are anaerobically digested by a two stage system having a
primary digester volume of 5.275 cu m (188,400 cu ft) and a secondary
digester volume of 2,249 cu m (80,000 cu ft).
The effluent from final clarification is chlorinated in a contact tank
having a volume of 605.6 cu m (160,000 gal.). At a flow of 113,550
cu m/day (30 mgd) (maximum through primary sedimentation) the detention
time in this tank is 7.7 minutes plus an additional 7-3 minutes in the
discharge conduit to Lake Michigan.
SEWERAGE SYSTEM
The 5.39 sq km (2.08 sq ml) of combined sewers in Kenosha are denoted by
the cross-hatched markings in Figure 1. There are three major trunk
sewers draining this area. These trunk sewers intersect the interceptor
sewer which runs parallel to Lake Michigan and slopes towards the WPCP.
The three trunk sewers and the interceptor are shown in Figure 2. There
were also two other combined sewer overflow discharges which were
removed during an earlier sewer separation program. Prior to construction
of the Interceptor sewer In 1939. the trunk sewers discharged directly
to Lake Michigan.
At all three overflow locations, 57th Street, 59th Street, and 67th
Street, the type of regulator mechanism used for entrance to the Inter-
ceptor is a horizontal drop inlet. This consists of a dam across the
width of the trunk sewer at the crown of the interceptor. Upstream of
this dam a circular orifice is cut into the interceptor allowing the dry
weather sewage to enter. During periods of runoff and high flow the
depth of flow in the trunk sewer exceeds that of the dam and the excess
flow discharges to Lake Michigan. When the flow in the interceptor
exceeds the capacity of the WPCP the hydraulic gate at the entrance to
the treatment plant is manually closed. This causes the interceptor to
begin filling, and eventually surcharge if the high flows continue.
Figure 3 contains a schematic diagram of the typical overflow mechanism
in Kenosha.
The interceptor itself Is approximately 2,743 m (9,000 ft) long,
beginning at 57th Street and terminating at the WPCP. At 57th Street the
interceptor is fed by a 152 cm (60 In.) sewer referred to as the North
Side interceptor. However, the area served by this interceptor is
entirely separated. At 57th Street the Interceptor is 137 cm (54 in.) in
diameter having a slope of 0.09U. Approximately 305 m (1,000 ft)
downstream, the diameter Increases to 152 cm (60 in.) and the slope reduces
to 0.053%. The Interceptor remains at this slope for another 1,128 m
(3,700 ft) before increasing to a 183 cm (72 In.) diameter with a slope
of 0.0432 for the last 1,311 m (4,300 ft) leading to the WPCP. This last
leg of the interceptor has a rated capacity of 189,250 cu m/day (50 mgd).
-------
KENOSHA
WISCONSIN
CITY LIMITS
CROSSHATCHED AREA
IS COMBINED SEWER SYSTEM
AREA SERVED BY
COMBINED
Figure 1. Map of Kenosha indicating combined sewer area
-------
57th
59th
OF KENOSHA
72" OVERFLOW
48MOVERFLOW
LAKE
MICHIGAN
OVERFLOW
•• INTERCEPTOR
ZEE OVERFLOW
HZ STREET
TO
TREATMENT
PLANT
Figure 2. Illustration showing interceptor sewer
and combined sewer overflow discharge locations
-------
ORIFICE
L
DAM
TO LAKE
•*•
INTERCEPTOR
Figure 3- Typical Kenosha overflow mechanism
-------
SECTION V - SYSTEM DESIGN AND CONSTRUCTION
CONTACT STABILIZATION PROCESS THEORY
Contact stabilization is a term describing one of the many modifications
of the conventional activated sludge process. Descriptions synonymous
with contact stabilization include physical adsorption, blosorption, and
sludge reaeration. What these terms describe is a process in which return
activated sludge from final clarification is aerated prior to mixing
with the wastewater to be treated. This reaeration time can vary In a
range from I hour up to many days. The mixing of the aerated sludge
with the wastewater is similar to conventional activated sludge, excepting
that the time for this mixing is usually between 15 and 60 minutes,
rather than many hours. It is often assumed that when contact stabiliza-
tion is used a very high mixed liquor concentration Is necessary.
However, it is usually true that the mixed liquor concentration is within
the normal range of conventional mixed liquor concentrations, 2000-4000
mg/1 for domestic wastes. Following the mixing, or contact tank, is
final clarification, functioning in the same manner as in normal
treatment processes, with the return sludge going to the stabilization
tank.
The main advantage of this process Is the small amount of aeration
capacity needed. Instead of using the entire length of an aeration tank
for the mixed liquor to complete the oxidation and digestion of the
organic matter in the wastewater, this process concentrates the mixed
liquor (active sludge and wastewater solids) in the clarification tank
and then allows for completion of the biochemical metabolic processes In
the stabilization tank. This tank only requires a volume of 10-25& of
normal aeration tanks. The contact tank volume is only 5-20% of the
normal aeration tanks. Thus, the aeration facilities needed are usually
1/5 to 1/2 of that in conventional plants. A schematic diagram of the
contact stabilization process Is shown in Figure k.
What makes this entire process possible is the rapid initial uptake of
organic matter, both soluble and insoluble, immediately upon the mixing
of a wastewater with an active sludge. This rapid initial uptake has
been a matter of controversy through the years. The question is whether
this uptake is a physical surface phenomenon (adsorption) or a biological
reaction (absorption). The rapid initial uptake upon mixing an active
sludge and wastewater has been known and studied since 1868 (3) when
researchers began developing the biological clarification theory (4)^5)
(6). In a review of the literature on this subject, Theriault in 1935
12
-------
WASTE
SLUDGE
STABILIZED
SLUDGE
RAW WASTE
FLOW
STABILIZATION
TANK
CONTACT
TANK
RAS LINE
EFFLUENT
»
TO
CHLORINAtlON
Figure A. Schematic diagram of contact stabilization process
-------
(7) summarized the high initial removal of organic matter by activated
sludge as having some indication of biological action in adsorption.
However, it appeared to be mostly physical. If in fact biological
reactions were present in this initial removal of solubles, then the
soluble removal could be termed absorption. In an editorial in 1935 the
Sewage Works Journal (8) called for a detailed study and conclusions to
this question.
Heukelekian responded by directing a long and thorough study between 1936
and 1938. In his first two experiments (9) (10) he found that inorganic
removal was a result of physical surface adsorption, but that oxygen was
necessary for clarification. Further tests were conducted to study the
importance of oxidation (II). Using a pilot plant activated sludge system,
return activated sludge and sewage were mixed, with C(>2 production
measured as a gauge of biological activity or BOD removal. Since the
highest rate of C02 production occured during the initial period of
mixing and removal, it was concluded that a high degree of biological
activity is taking place during this removal phase. Further tests were
then conducted to show the importance of biological activity in removal
What this long and involved study concluded was that biological activity
was present to some degree in the initial clarification stage of an
activated sludge process. It had been shown that biological activity was
the most Important factor in the removal of solubles, and it also had been
indicated that biological activity was important in the removal of the
insolubles, by adsorption. However, no explanation of how this last
activity occurred was given. In 19^0 a most important work appeared
(15) which proposed an explanation of biological activity In physical
adsorption. From his tests the author concluded that adsorption is
dependent upon biological processes and precludes reduction, and that
floe is viewed as consisting of an inorganic nucleus surrounded by a
layer of, enzynatical ly active material.
Following the period of 1930-19^0 when a great deal of research was
carried out regarding the initial clarification stage in activated
sludge, there was a lack of literature until the contact stabilization
process .started to gain acceptance (16). During the mid-1950's
literature concerning contact stabilization and/or its associated
theories began appearing once again. Katz and Rohlich conducted a very
detailed study of the kinetics of activated sludge adsorption. They
assumed that the controlling mechanism in the rate of adsorption of
impurities on to a floe particle was a stagnant film of water surrounding
the floe, .Although their results showed adsorption to be described in
terms of firm, physical mathematics, their discussion was prefaced by
the statement that enzynatic action was not precluded, and, in fact,
mass transfer (adsorption) may be largely a result of the pressure of
enzymes .
-------
Eckenfelder explained why there ts a leveling off of BOD removal after the
initial clarification. He summarized the removal of BOD when organic
wastes are contacted with sludge as follows (18):
I. Suspended and finely divided solids are removed by adsorption and
coagulation.
2. A portion of the soluble organic matter is initially removed by
adsorption and stored in the cell as a reserve food source.
3. Additional dissolved organic matter is progressively removed
during the aeration process resulting in the synthesis of sludge
and the production of CO- and water. The rate of BOD removal
after the initial adsorption is dependent upon the concentration
of BOD to be removed and the concentration of the sludge solids.
What is important in Eckenfelder's theory is the storage capacity of the
cells present in the sludge. Thus, a sludge which is still viable but
yet limiting on food, or a sludge which is in its log growth phase, will
produce excellent initial removals of BOD, since storage capacity will
be optimum.
As late as 1966, the majority of the literature still referred to adsorp-
tion as a completely physical process. Siddiqi published an article at
this time (19) which stated the definite role of biological enzymes in
the adsorptive removal of soluble materials. From actual bench scale
activated sludge tests, he concluded that there is a substantial
significance to the role of enzymes in soluble organic removal. His
data showed that the enzymatic processes are particularly significant in
substrate removal as opposed to the widely accepted surface removal
phenomenon. It was also shown that specific hydrolyzing enzymes are
needed for the breakdown and adsorption or organic materials, and that if
sludge is stabilized too long before mixing with sewage, there can be a
loss of bioactivlty, and as a result, a lack of the necessary enzymes.
In conclusion, the century of study on the initial clarification of a
wastewater by activated sludge can be summarized as follows:
1. Particulate matter is rapidly removed from the liquid phase by
adsorption onto the surface of a floe material. The reaction
appears to include the use of some enzymes.
2. Soluble material is adsorbed to the surface of a floe particle
and simultaneously absorbed into the cellular material present.
This reaction is dependent upon biological enzymes and the
condition of the biological sludge present. This reaction rate
can be described, however, in the same terms used to describe
physical adsorption.
-------
CONTACT STABILIZATION OPERATING EXPERIENCE
The actual use of some form of the contact stabilization process was
reported as early as 1910 (20). In 1910, Black and Phelps achieved good
removals in an activated sludge plant using only 3 hours mixing time, and
an aeration rate of .00169 cu m of air per liter (0.23 cu ft of atr per
gallon). At Houston, Texas in 1915, test runs showed 98$ suspended
solids, and 3k% oxygen demand removals with a return sludge flow rate of
30% and only one hour of aeration time. The most publicized contact
stabilization process in the United States is located in Austin, Texas
(16). Here a conventional activated sludge plant operated for 12 years
with unsatisfactory results due to sludge bulking. After much study it
was felt that this bulking was due to over aeration. Laboratory experi-
ments found mixed liquor settling characteristics to be the best after
only 15-30 minutes of aeration.
In 1950, a 0.95-1.25 I/sec (15-20 gpd) contact stabi1ization pilot plant
was built to test this process on the waste being treated by the
conventional plant. Results from this pilot plant indicated that 1)
using a good activated sludge and raw sewage with a detention tjme of
15-30 minutes that BOD and suspended solids removals of 90-95% were
possible, 2) a good return activated sludge flow would be the same as
in a conventional plant, based on the maximum flow, 3) 90 minutes of
reaeration is needed to reactivate the adsorptlve and absorptive
properties of the sludge, 4) the settling characteristics of the absorbed
floe are better than in a conventional plant, and 5) the buildup in
sludge (waste) is the same as in a conventional plant. Based upon the
successful operation of the pilot plant the conventional treatment plant
was converted to a contact stabilization plant. Operational results from
1955 Indicated 93% BOD removal (raw - 307 mg/1) and 92% suspended solids
removal (raw = 226 mg/1), a raw flow of 29,144 cu m/day (8.7 mgd) with
a return sludge flow of 4l% and a MLSS concentration of 1,896 mg/1 (21).
Another conventional treatment plant that was overloaded and converted to
contact stabilization was in Bergen County, New Jersey (22). Comprehen-
sive laboratory tests were run on the wastewater at this plant in order
to determine design criteria for conversion to contact stabilization.
Based upon these results the process was designed and operated success-
fully with an aeration time of 0.44-1.68 hours, a sludge reaeration time
of 2-6 hours, an air supply of 61.7 cu m/kg (1,000 cu ft/lb) of BOD
removed, and a BOD loading of 0.46-4.00 kg/day/cu m (29-250 lb/day/1000
cu ft) of aeration volume.
Other, reported operating parameters from successful contact stabilization
plants include a textile mill (23) treating a waste with a BOD of greater
than 500 mg/1 and a suspended solids concentration of 90-120 mg/1. BOD
removals of 85-90% are achieved with the following:
16
-------
BOD loading 2.43 kg/day/cu m (150 lb/day/1000 cu ft)
aeration
Optimum MLSS 2500-4000 mg/1
Optimum stabilized sludge 6000-8000 mg/1
Optimum reaeration time 2-4 hours
Optimum contact time 45-75 minutes
Air requirements 49-3-61.7 cu m/kg (800-1000 cu m/lb)
BOD removed
Clarifier SOR 30.6 cu m/day/sq m (750 gpd/sq ft)
Wastes from a potato processing industry having BOD, COD and suspended
solids concentrations greater than 1000 mg/1 have had better than 80%
removal of these parameters using contact stabilization with contact
times of one hour and reaeration times of 6-8 hours.
Because of the ability of contact stabilization to adjust to variations
in loadings and flow rates, the process has gained much use as a package
treatment plant. This is exemplified by two contact stabilization plants
constructed in a suburb of Houston, Texas (25). These plants which
treat only domestic wastes have a design contact time of 1.5 hours and
a reaeration time of 6.0 hours. What is especially unique about these
plants is their design. Clarification, contact, reaeration, digestion,
and chlorination are all carried out in one basic unit. The disadvantage
of these plants is their inability to completely remove soluble organ!cs
when present in high amounts (26).
SYSTEM DESIGN FOR KENOSHA
The main difference between normal contact stabilization processes and
the application for treating potential combined sewer overflow in Kenosha
is the periodic usage of the system. In conventional contact stabiliza-
tion RAS is continually transferred from the underflow in the final
clarifier to the stabilization tank where it is reaerated for a period
of hours and then transferred to the contact tank. However, since the
demonstration system was only to be used periodically, it was necessary
to provide some means of always having a viable stabilized sludge
ready for use. It was decided to utilize the WAS from the existing dry
weather plant (DWP) as a source of biological solids in the stabilization
tank. The WAS from the DWP would be diverted to the stabilization tank
during dry weather. The sludge would be detained in the stabilization
tank for a period of time (to be determined during the evaluation
-------
program) before going on to the DWP flotation thickeners. The WAS would
continually enter and leave the stabilization tank, and the detention
time would be governed by the volume of sludge in the stabilization tank.
(The detention time between uses of the demonstration system is termed
the stabilization time and the detention time during use of the system is
termed the reaeration time.)
Another important consideration governing the design of the demonstration
system was the use of some of the demonstration system facilities by the
DWP when the demonstration system was not in operation.
Design of the demonstration facilities required a great amount of
flexibility in operating conditions for purposes of the evaluation program.
Provisions had to be made for the following conditions.
I. Raw flow rates between zero and 75,700 cu m/day (20 mgd).
2. Contact times of at least 15 minutes at a raw flow of 75,700
cu m/day (20 mgd) and variable contact times for flows less than
75,700 cu m/day (20 mgd).
3. The ability to transfer sludge from the stabilization tank to
the contact tank during system operation at any rate between
zero and 75,700 cu m/day (20 mgd).
k. Sludge stabilization periods of any duration up to seven days
based upon an average WAS rate of 378.5 cu m/day (100,000 gpd)
by the DWP.
5. Sludge reaeration times which could be varied for any return
sludge rate between zero and 75,700 cu m/day (20 mgd).
6. Aeration to the contact tanks at a variable rate depending upon
the raw flow rate.
7. Aeration to the stabilization tank where the sludge level and
volume would be variable.
8. Return sludge rates from the final clarifier to the stabiliza-
tion tank of zero to 75,700 cu m/day (20 mgd).
9. Use of the final clarifier by the DWP when the demonstration
system was not operating, but yet be able to isolate this
clarifier for use by only the demonstration system during
periods of potential overflow.
10. Keeping variables such as sludge transfer rate, air supply, and
return sludge rate a constant percentage of the raw flow even
though the raw flow rate would vary during operation.
18
-------
Following is a description of the design of each unit operation of the
demonstration system.
Pumping Plant
Although the DWP had a total raw flow pumping capacity of 189,250 cu m/
day (50 mgd) comprised of a 75,700 cu m/day (20 mgd) gas driven pump,
a 37,850 cu m/day (10 mgd) gas driven pump, and two 37,850 cu m/day
(10 mgd) electrically driven pumps, limitations on the electrical input
capacity made it Impossible to operate the two 37,850 cu m/day (10 mgd)
electrically driven pumps simultaneously. Thus, if the 75,700 cu m/day
(20 mgd) gas driven pump was out of service, the pumping capacity of
the plant would only be 75,700 cu m/day (20 mgd). Therefore, a 94,625
cu m/day (25 mgd) gas driven pump was specified to replace one of the
37,850 cu m/day (10 mgd) electrically driven pumps. This pump was able
to utilize the existing 76 cm (30 in.) diameter discharge header pipe
already present. Only minor extensions to the existing pipe layout
were necessary to allow the discharge from this pump to go to the
existing DWP grit chambers or to the demonstration system. Figures 5 and
6 show the new pump motor and its location in the WPCP pump room.
Grit Tank
DWP operational experience had indicated that grit removal became a
problem during the year when flows exceeded 9^,625 cu m/day (25 mgd).
As a result, an existing chemical mixing basin no longer in use was
converted into a grit tank for use by the demonstration system. Conversion
of this tank required raising the level of the existing walls and channels
to put the tank in hydraulic balance with the rest of the system, and
installation of inlet and outlet piping. In an effort to reduce costs no
provisions were made for mechanical removal of the settled grit.
The tank is 17.22 m (56.5 ft) long, 6.86 m (22.5 ft) wide, and has a mean
depth of 2.7^ m (9 ft). At a flow of 75,700 cu m/day (20 mgd) the
horizontal velocity is less than 0.061 m/sec (0.2 ft/sec). The floor
of the tank is sloped from all extremities toward the middle 6.10 m
(20 ft) of one wall. A well screen drains the tank after use. Figure 7
is a view of the grit tank from the influent end of the tank.
Contact Tank
The contact tank was designed to provide a minimum of 15 minutes contact
time based upon a raw flow of 75,700 cu m/day (20 mgd). As part of the
evaluation program it was necessary to study the effects of different
contact times. Therefore, the contact tank was subdivided by a concrete
wall into two compartments of different volumes. This allowed for equal
flows to be run at three different contact times. This was done by using
each compartment separately, or using them both simultaneously, resulting
in three different effective volumes. One compartment of the contact tank
-------
Figure 5- View of gas driven pump engine
Figure 6. New gas driven engine and pump shown
in relation to existing pumping facilities
(new pump is at the top of photo)
20
-------
Figure ?• View of grit tank from influent end
-------
has a volume of 620.7 cum (164,000 gal.) and the other compartment a
volume of 304.7 cu m (80,500 gal.) resulting tn a total volume of
925-4 cu m (244,500 gal.). The compartments are both 9.14 m (30 ft)
wide and are divided into lengths of 7-01 and 17-07 m (23 and 56 ft),
having sidewall depths of 5-33 m (17-5 ft). Located along one wall of
the tank is a feed trough where the grit tank effluent and the transferred
sludge from the stabilization tank are mixed before entering the contact
tank. Eight portholes, four leading Into each compartment, are located
in the wall of the feed trough. These portholes can be easily closed off
to prevent flow from entering one of the compartments if desired.
Figure 8 is a view into the larger compartment of the contact tank. At
the left is the feed trough and portholes. At the bottom right is the
fixed air disperser system. At the top right is the weir over which the
mixed liquor passes into the trough leading to the final clarifler. On
the far side of the concrete wall in the middle of the picture is the
smaller compartment. In the far background is the stabilization tank.
Figure 9 shows the various contact times that can be achieved at different
flow rates.
Stabilizatlon Tank
Design of the stabilization tank required dividing the tank into two
smaller compartments so that different volumes could be utilized. Also,
the intakes for the sludge transfer pumps were located near the bottom
of the stabilization tank so that the level of the tank could be varied,
producing any desired volume of sludge. The stabilization tank was built
with two 29.26 m (96 ft) long sections divided by a concrete wall. At
the bottom of the wall is a mechanical sluice gate which, when open,
allows the two compartments to function as one tank. At a depth of 2.13
m (7 ft), there are permanent openings in the concrete wall connecting
the two compartments. Both compartments are 9.14 m (30 ft) wide with
side wall depths of 5-33 m (17*5 ft). Each compartment has a volume of
1386.4 cu m (366,300 gal.). RAS from the final clarifier can be pumped
into both compartments simultaneously or just into the compartment
closest to the contact tank if desired.
Figure 10 is a view into one of the empty compartments of the stabilization
tank. The concrete wall divides the stabilization tank into the two
compartments. Directly behind the second compartment is the contact tank.
The floating mechanical aerators can be seen in the center of the tank.
At the bottom right is the RAS feed line to the stabilization tank.
Figure 11 is a view into the stabilization tank from a platform between
the stabilization and contact tanks. Figure 12 depicts the different
reaeration times that are achieved at different levels for various
RAS and sludge transfer rates.
22
-------
Figure 8. View of larger compartment of contact tank. Disperser system
is shown at lower right and overflow weir at top right
-------
V)
JS
I
UJ
5
»-
o
o
O
60 L
50
40
3O
20
IO
BOTH
COMPARTMENTS
LARGE
COMPARTMENT
ONLY
SMALL
COMPARTMENT
ONLY
0 18,925 37,850 56,775
0 5 IO 15
Figure 9- Contact times versus various flow rates
75,700 CU. M/ D
20 M60
-------
Figure 10. View of one stabilization tank compartment while empty.
Floating surface aerators are shown at bottom of tank.
25
-------
Figure 11. View of full stabilization tank
from platform between stabilization and contact tanks
26
-------
I
Q.
LU
Q
FT. M
16.4 5
13.1 4
9.8 3
6.6 2
3.3 I
I
>-. .0
i i
i i i
0
40
80
120
160 200 240
REAERATION TIME - MINUTES
Figure 12. Stabilization tank depth versus reaeration time at various flows
-------
Sludge Transfer Pumps
Two constant speed 37,850 cu m/day (10 mgd) pumps were Installed between
the stabilization tank and contact tanks for transferring the sludge
from the stabilization tank to the contact tank feed trough during
system operation. A throttling valve is located on the discharge line
from these pumps to permit the desired rate of sludge to reach the
contact tank. This rate Is set as a percentage of the raw flow rate.
A 1892 cu m/day (0.5 mgd) pump was also Installed at the same location.
The function of this pump is to transfer stabilized sludge to the DWP
thickening facilities when the demonstration system is not In use. A
throttling valve is located on the discharge line of this pump, enabling
this flow rate to equal the OWP RAS flow rate to the stabilization tank.
Figure 13 is a schematic drawing showing plan and elevation views of the
contact and stabilization tank arrangement.
Oxygen Requirements
The oxygen requirements for the system were calculated to be 8,080 kg/day
(20,000 Ib/day). It was estimated that 3,178 kg/day (7,000 Ib/day) would
be required by the contact tank and 5,902 kg/day (13,000 Ib/day) by the
stabilization tank. The total air blower capacity of the existing treat-
ment plant was 373.8 cu m/min (13,350 cfm). The maximum air requirements
by the DWP was 273,0 cu m/min (9,750 cfm) with an average demand of
147.0 cu m/min (5,250 cfm). Assuming an oxygen transfer efficiency of 7%,
the demonstration system demand would be about 112.0 cu m/mln (4,000 cfm)
in the contact tank and 224 cu m/min (8,000 cfm) in the stabilization
tank. Since it was obvious that the existing air blower capacity was not
sufficient for the total demand, It was decided to use the existing air
blowers for the contact tank and to supply floating mechanical surface
aerators for the stabilization tank.
The air disperser system in the contact tank consists of 340 dlspersers.
The air supply to these dispersers comes from the existing plant's
blowers. As built, the sytem is capable of delivering between zero and
105.0 cu m/min (3,750 cfm) of air to the contact tank. The rate of air
supply is automatically controlled by the raw flow rate to the
demonstration system.
Eight 37.3 kw (50 hp) floating mechanical surface aerators, four in each
compartment, were specified for the stabilization tank. At an oxygen
transfer rate of 1.52 kg/hr/kw (2.5 Ib/hr/hp) a total of 10,896 kg/day
(24,000 Ib/day) of oxygen can be supplied to the stabilization tank by
these aerators. Floating surface aerators were chosen since they I) would
not require an addition to the existing air blower facilities, 2) were
all suited for the changing depth in the stabilization tank and 3) would
insure adequate mixing and prevent deposition of solids. Each aerator
is controlled individually so that the number of aerators in use can
be varied depending upon the specific application (stabilization or
reaeration).
28
-------
STABILIZATION TANK
CONTACT TANK
1
274.3 M
3OFT.
1
I
O
o
o
29.3 M I, 29.3 M
96 FT. 96 FT.
, 7.92 Mr|. 16.2 M I
26 FT. 53 FT .
D—-r-
5.73 M
17.5 FT.
Figure 13. Plan and elevation views of stabilization tank and contact tank
-------
Final Clarifler Equipment
Design of the final clarlfier was performed so that the clartfier could
easily be integrated into dry weather use. Construction of the clarifier
required connection to the existing DWP mixed liquor feed channel, hook-*
up with the DWP RAS system, and a separate 75.700 cu m/day (20 mgd) RAS
pump and associated yard piping to the demonstration system. A sluice
gate was installed at the entrance point of the DWP mixed liquor feed
channel to the clarifier. This gate remains open during periods of
dry weather flow. When the demonstration system goes into operation the
gate automatically closes, isolating the new clarifier from the DWP.
A valve located within the conduit leading from the new clarifier to the
DWP RAS pumping facilities also automatically closes.
The size of the final clarifier was based upon bench scale laboratory
tests using mixed liquor from the Kenosha WPCP. As a result a 42.7 m
(140 ft) peripheral feed and efflent clarifier with a surface overflow
rate of 53-0 cu m/day/sq m (1300 gpd/sq ft) at a flow rate of 75,700
cu m/day (20 mgd) was specified and constructed. The clarifier has a
gross surface area of 1,431 sq m (15,400 sq ft), a volume of 5,299 cu m
(1,400,000 gal.) and a sidewall depth of 4.18 m (13.7 ft).
Figure 14 gives an overall view of the clarifier. A more detailed picture
of the clarifier, Figure 15, shows, from left to right, the scum baffle,
effluent trough, deflector shirt, and feed trough.
For purposes of conveying the RAS from the new final clarifier to the
stabilization tank a 75,700 cu m/day (20 mgd) pump was installed in the
DWP RAS building. A throttling valve on the discharge side of this pump
works in the same manner as the valve associated with the sludge transfer
pumps. Unless it is desired to change the level in the stabilization tank,
the flow rate from the RAS pump and the sludge transfer pumps will be
identical. Piping provisions were also made to allow RAS to be pumped
from the DWP system to the stabilization tank if necessary.
Instrumentation and Control
A sophisticated and highly automated control system was specified for the
demonstration system. This was partially necessitated by the evaluation
program to be carried out, which required the maintaining of some process
variables as fixed percentages of the varying raw flow. Also, a large
amount of valve and gate position changes were required in a matter of
minutes when the demonstration system went into operation and this
precluded manual operation.
A control panel was constructed in the Administration Building of the
WPCP. This panel can be seen In Figure 16. The functions handled by
this panel are listed below:
30
-------
Figure 14. Overall view of final clarifier
Figure 15. Detailed view of clarifier showing scum baffle,
effluent trough, deflector skirt, and feed trough
31
-------
.
a j
I
,J w
< c
.
A 4^* ' *
-« .
t
Figure 16. View of demonstration system control panel
-------
1. Record raw flow rate.
2. Indicate level of flow In the DWP grit tank.
3. Activate annunciator at onset of high flow conditions.
k. Totalize flow and duration of demonstration system use.
5. Open/close valves in discharge line from new gas driven raw
flow pump which direct flow to either the DWP or the demon-
stration system.
6. Control throttling valve for WAS rate from the OWP to the
demonstration system.
7. Control throttling valve for WAS rate from the stabilization
tank to the sludge thickening facilities.
8. Control throttling valve for the RAS rate from final clarifier
to the stabilization tank.
9. Control throttling valve for sludge transfer rate from the
stabilization tank to the contact tank.
10. Control throttling valve for therateof RAS borrow from the DWP
by the demonstration system.
11. Control throttling valve for rate of air flow to contact tank.
12. Indicate effluent flow rate from Parshal1 Flume on final clarifier,
13. Start/stop automatic samplers.
14. Open/close sluice gate at entrance to new clarifier from DWP
mixed liquor feed channel.
15. Open/close sluice gate at entrance to new clarifier from
demonstration system mixed liquor feed channel.
16. Open/close valve in RAS conduit leading from new clarifier to
DWP RAS pumping system.
17- Open/close valve In RAS conduit leading from new clarifier to
demonstration system RAS pump.
18. Control three timer mechanisms responsible for automatic startup
of the demonstration system.
19. Control automatic start/stop operation of the raw flow pump,
the two sludge transfer pumps, the RAS pump, and the sludge
transfer pump from the stabilization tank to the DWP thickener.
33
-------
The throttling valve controlling the WAS rate from the DWP to the
stabilization tanks during dry weather is manually positioned for the
desired flow rate at the control panel. The throttling valve for the
WAS flow rate from the stabilization tank to the DWP thickener is paced
by the WAS rate to the stabilization tank. The WAS flow rate to the
thickener can be set anywhere in a range between zero and 300% of the
flow rate to the stabilization tank. For normal dry weather use when
the two flow rates should be equal, this ratio is set at 100%. It is
also possible to manually set a desired WAS flow from the stabilization
tank regardless of the flow rate into the tank.
The throttling valves for the RAS flow rate from the clarifier to the
stabilization tank and for the sludge transfer rate from the stabilization
tank to the contact tank are both paced as a percentage of the raw flow
rate. These rates are set in a range of zero to 100% of the raw flow
rate (0-75,700 cu m/day) (0-20 mgd). The actual setting is dependent
upon the desired mixed liquor suspended solids (MLSS) concentration
desired. During normal operation, these two settings are the same in
order to maintain a constant level in the stabilization tank. It is also
possible to manually set these flows at a desired rate. A throttling
valve for the rate of RAS borrow from the DWP works in the identical
manner, having the same capacities.
The throttling valve for the rate of air flow performs similar to the
above valves. The ratio controller can be set between zero and 300%. At
a raw flow rate of 75,700 cu m/day (20 mgd) and the controller set at
100%, the air flow is 105.0 cu m/min (3,750 cfm). This is the maximum
air flow capacity. At lower flows such as 37,850 cu m/day (10 mgd), the
controller can be set at 200%, resulting in the same 105.0 cu m/min
(3,750 cfm) rate. It is also possible to manually set the air flow rate
anywhere between zero and 105.0 cu m/min (0-3,750 cfm).
SYSTEM DEPLOYMENT
Integration of the demonstration system into the DWP operation makes
quick implementation of the process possible when potential overflow
conditions exist. Figure 17 illustrates the relationship of the
demonstration system to the existing DWP.
The level indicator located in the DWP grit tank continually relays the
DWP flow rate to the demonstration system control board. If this rate
goes above 87,055 cu m/day (23 mgd) an alarm is sounded and the delay
timer at the control board begins operation. The purpose of this timer
is to allow operating personnel to respond to the alarm, and determine
if there is any reason why the system should not be allowed to begin
operation. If there is no reason for aborting the run, the timer will
complete its cycle and then immediately start the process.
The raw flow pump will automatically start, if not already being used
by the DWP. The valve leading to the DWP on the discharge line from
-------
ADMINISTRATE
WET WEATHER GRIT
BASIN
PRESENT
MIXING
BASIN
-\ BLOWER s
BUILDING
WET
WEATHER
FINAL
TANK
THICKENER
BUILDING
ELECTRICAL
SUBSTATION
CHLORINE BUILDING
CHLORINE
CONTACT TANK
ft. ^J
FINAL EFFLUENT
RELATIONSHIP OF DEMONSTRATION SYSTEM AND CONVENTIONAL
TREATMENT PLANT
Figure 17- Plan view of Kenosha Water Pollution Control Plant
35
-------
the pump will close, and the valve leading to the demonstration system
will open. Raw flow will fill the grit tank and then begin flowing to
the feed trough at the contact tank.
An electrical probe is located in this trough, and when the flow makes
contact with this probe the remaining start-up functions take place.
The sluice gate in the mixed liquor feed channel from the DWP to the
demonstration system clarifier begins a 30 minute closing cycle, and
the sluice gate in the mixed liquor feed channel from the contact tank
opens. Simultaneously, the RAS line leading from the demonstration
system clarifier to the DWP RAS pump is automatically valved shut,
the valve in the RAS line leading to the demonstration system RAS pump
opens, the demonstration system RAS pump and sludge transfer pumps begin
operation, and the throttling valve for the air supply to the contact
tank opens. Also, the RAS line leading from the DWP to the stabiliza-
tion tank is valved shut, and the transfer pump for the WAS going from
the stabilization tank to the DWP sludge thickener shuts off. At the
beginning of operation it is also necessary to manually increase the
chlorine dosage to the chlorine contact tank.
When the high flow condition has subsided, the demonstration system
is manually taken out of service at the main control board. After
turning ,the process off, the start-up procedures automatically reverse
themselves and the plant returns to normal dry weather operation. The
remaining mixed liquor in the contact tank is pumped by one of the
sludge transfer pumps to the DWP primary sedimentation tanks. The
grit tank is drained and the settled grit on the bottom of the tank is
manually scraped to the side of the tank where it is removed by a Vac-
all and transported to a landfill site.
CONSTRUCTION COSTS AND TIMING
During the period of September 9, 1969 to March 5, 1970 the initial
design report was prepared and then reviewed by the City of Kenosha and
the US EPA. Following the report review the plans and specifications
were completed and reviewed by the State of Wisconsin Department of
Natural Resources and the US EPA. Bids for construction were received
on August 11, 1970 and the actual construction contracts were signed
on October 26, 1970, with construction starting immediately. The
contractor was required to complete all facilities within 2^0 calendar
days, or 8 months. Unfortunately, due to winter weather and construc-
tion delays, the actual period of construction was 11 months with
construction completed on August 18, 1971. The remainder of August, and
and the months of September and October were spent in debugging the
equipment, checking instrument calibration, and familiarizing personnel
with the methods of operation.
36
-------
The biggest delay In making the system operational following completion
of construction was caused by problems with automatic flow controllers
and throttling valves. During shakedown tests using dry weather flow,
it was found that the thorttling valves were not being paced properly.
This required repeated repair visits by service representatives of the
Instrument manufacturer. Not until the end of October was it felt that
the system was ready for actual operation. However, by this time it
was necessary to take the system out of service for the winter months.
The system was put back on line and ready for operation following the
spring thaw during the first week of April, 1972.
Total construction costs came to $1,178,779.11. General construction
costs were $1,023,150.00, and the electrical construction cost was
$69,600.00. The engineering costs including design and inspection
amounted to $86,029.00. Table 1 contains a detailed cost breakdown for
the various aspects of construction. The general contractor was C £ C
Bohrer Inc., Fort Wayne, Indiana, and the electrical contractor was
Oietz Electric of Milwaukee, Wisconsin. Figure 18 is an aerial photo-
graph of the entire Kenosha WPCP after construction of the demonstration
system was completed.
Table 1. BREAKDOWN OF CONSTRUCTION COSTS
Item Final cost
Excavation $ 67,620.00
Backfill 21,367.00
Reinforced concrete 280,150.00
Concrete pipe 93,200.00
Demolition 13,505.00
Miscellaneous metal 20,338.00
Paint and finish IA,306.00
Landscape 5,000.00
Steel pipe 29,269.00
Cast iron pipe 51,030.00
Spiral piping 5,000,00
Valves 78,765.00
Meters and instruments 55,000.00
Pumps 85,000.00
Sludge collectors 105,000.00
Diffusers 5,000.00
Weirs and troughs 25,000.00
Mechanical aerators 76,000.00
Change orders 2,600.11
$1,023,150.11
Electrical work 69,600.00
TOTAL..... $1,092,750.11
37
-------
Figure 18. Aerial view of Kenosha WPCP depicting
demonstration system facilities
-------
SECTION VI - OVERFLOW QUALITY STUDY
During 1970 while design and construction of the demonstration system
facilities was occurring, a program to determine the quality of the
combined sewer overflows in Kenosha was carried out. This included
measurement of rainfall, combined sewer overflow quantity and quality,
and influent quality to the WPCP during rainfalls.
INSTRUMENTATION
Two raingages were installed to substantiate the results from the
official U.S. Weather Service raingage located on the grounds of the
WPCP. The raingage locations are shown in Figure I9» and are designated
as follows: Gage A - on the roof of a Kenosha Fire Department firehouse
at J»8th Avenue and 60th Street, in the northwest corner of the combined
sewer area. Gage B - on the roof of the Kenosha Water Utility Building
at 100 51st Place just outside the northeast corner of the combined
sewer area. Gage C - ground level at the WPCP, 3rd Avenue and 79th
Street, just outside the southeastern corner of the combined sewer area.
The two raingages installed were both Bendix Raingages, Model No. 775~C.
These instruments have a range of 30.5 cm (12 in.) and convert the
weight of water collected to linear readings. The readings are recorded
on a cylindrical chart divided into 2k equal segments, recording
cumulative depth of precipitation vertically and time horizontally.
The cylindrical chart recorder is powered by a spring driven clock
which has a 2k hour rotation and an 8 day wind cycle. Each site was
maintained on a seven day interval, or after each rainfall, depending
upon which came first. This maintenance included changing the record-
ing chart, refilling the recording pen, and checking instrument
calibration. The raingage at the WPCP used for data in this project
was similar to the others which were installed.
The method chosen for averaging the rainfall recordings from the three
instruments was the Theissen Method (27). This method was used because
of its accuracy when using non-uniform raingage distribution, as was the
case here. The percentage, or weight factor, applied to gages A, B,
and C were 0.37, 0.38, and 0.25 respectively.
The three overflow locations, 57th, 59th, and 67th Street, were located
in readily accessible areas and were subject to vandalism and tampering.
39
-------
KENOSHA, WISCONSIN
COMBINED SEWER
AREAS
Figure 19- Map of Kenosha showing raingage locations
/tO
-------
In order to minimize this problem, the overflow samplers and depth of
flow recording instruments were housed in 1.52 m (5 ft) diameter by
1.83 m (6 ft) precast manhole sections. Figures 20 and 21 picture,
respectively, an exterior view of a typical monitoring installation and
an interior view showing the flow recording and sampler instrumentation.
Sampling occurred at each location automatically during an overflow. The
sampling apparatus were commercial Serco Model No. NW-3-8 samplers. These
samplers operated by creating a vacuum in the sample jars and connecting
a sample line from each jar down into the overflow sewer. During an
overflow the vacuum on each sample bottle was released at 10 minute
intervals. There were 2k sample jars, thus allowing for a sample period
of 2AO minutes. Each jar had a volume of approximately 500 mis. The
sampler was initially triggered by means of a float anchored in the
overflow sewer. As an overflow began, the flow buoyed the float upwards
and thus opened a pinch valve which controlled a vacuum bottle contained
in the starting apparatus. This release of vacuum drove a piston which
In turn released a spring loaded arm that tripped the vacuum switch on
each separate sample jar, causing the jar to fill up with the sampled
1 iquid.
The depth recorders were manufactured by Honeywell and operated on a
differential pressure basis. Inert nitrogen gas was introduced into
tubing which ran between the recorder and the bottom of the outfall
sewer. As the flow (head) in the sewer increased, the nitrogen escaping
from the end of the tubing in the sewer was decreased, proportional to
the depth of flow, causing the pressure within the tube to increase.
This increase in pressure was converted to depth readings and recorded
on a circular chart. The chart was divided into 2k equal sections and
driven by an 8 day clock.
The 57th Street overflow was located at 57th Street and the lakefront.
The outfall pipe itself at this location is 1.83 m (72 in.) in diameter.
In order to install the float and sampling equipment a 0.61 m (24 in.)
diameter hole had to be bored from ground level down to the sewer, and
a portion of the top of the sewer had to be knocked out. A section of
culvert pipe was then installed from the sewer up to ground level.
The 59th Street overflow was located just east of the 59th Street and
3rd Avenue intersection, about 3\k.k m (1000 yards) west of the lakefront.
Monitoring equipment was installed at this location a month after the
others because a new manhole was being installed at this time. The
float and sampling equipment was installed in the 1.22 m (kB in.)
diameter outfall directly through the existing manhole.
The 67th Street overflow was located where 67th Street (extended) would
intersect the lakefront. The monitoring equipment was located on a
concrete pad containing the manhole above the 2.51 m (99 in.) diameter
outfall sewer. A general schematic diagram of a typical monitoring
station is shown in Figure 22.
-------
Figure 20. Exterior view of overflow monitoring station
Figure 21. Interior view of monitoring station showing
sampling and flow recording instrumentation
-------
1 . Vacuum operated start
valve
2. Clock controller
sampling arm
3. Sample bottles
4. Mechanical pinch valve
5. Vacuum starter bottle
6. Sampling head
Float-mechanical start
Tip bubble tube
Depth recorder
Pressure regulator
Nitrogen source
Figure 22. Schematic drawinq of a typical monitoring site
-------
A sampling site was also installed at the WPCP itself. The sampler was
located at the influent end of the indoor grit chamber. The purpose of
this location was to sample the sewage entering the treatment plant
during rainfall periods. The pollutional characteristics of this flow
gave a good indication of the quality of sewage to be treated later by
the demonstration system. The sampler installed at this location was
identical to the others and was manually started by treatment plant
personnel during rainfall periods.
MONITORING PROCEDURE
Following completion of installation of the raingages and sampling equip-
ment at the end of May, 1970, a continuous rainfall alert notification
system went into effect. During normal working hours the operator at
the WPCP telephoned the appropriate personnel at Envirex Inc. in Milwaukee
upon commencement of a rainfall. After working hours, or on weekends,
the WPCP operator telephoned the company security police who in turn
contacted Envirex personnel. Upon notification of the rainfall the
designated person from Envirex would immediately travel the 6k.k km
(40 miles) from Milwaukee to the sites to collect the samples when the
overflow ceased. At this time charts from both the raingages and depth
recorders were removed and marked with the proper identification numbers
regarding storm numbers, date, and time. These charts were returned
and the data was later extracted and recorded.
Sewer overflow samples were collected and composited proportional to the
flow. Using the flow recorder chart it was possible to determine the
flow rate at the time each sample was taken, and to take a volume of
sample proportional to this reading. After compositing the samples in
one gallon plastic containers, they were placed in styrofoam coolers
and transported to the Envirex laboratory in Milwaukee. The samples
were immediately prepared for BOD, total coliform and fecal coliform
analyses, with the remaining sample being refrigerated until used in
later analysis for determination of other pollutional characteristics.
A list of the quality characteristics measured is below.
1. pH
2. Settleable sol ids
3- Total solids
k. Total volatile solids
5. Suspended sol ids
6. Suspended volatile solids
7- Total BOD
8. Dissolved BOD
9. Total COD
10. Dissolved COD
11- Total organic carbon
12. Dissolved organic carbon
13- Total inorganic carbon
-------
14. Soluble Inorganic carbon
15. Total Kjeldahl nitrogen
16. Total phosphorus
17. Total col I form
18. Fecal col I form
Although the laboratory procedures generally followed those In the 12th
Edition of Standard Methods (28), a description of the exact laboratory
analytical procedures used is given in Appendix A.
PRECIPITATION DATA
Rainfall data (29) available through 1968 indicates that the City of
Kenosha received an average annual rainfall of 76.40 cm (30.08 in.).
For the period from 1958 to 1967, 5 years had annual rainfalls greater
than 76.40 cm (30.08 in.) and 5 years had annual rainfalls less than
76.40 cm (30.08 in.). The maximum annual rainfall in this period was
103.40 cm (40.71 in.) In I960. The minimum annual rainfall was 48.51 cm
(19.10 in.) recorded In 1963.
During the four and one-half month monitoring period from June 1, 1970
through October 14, 1970, twenty-five rainfall events were recorded.
These Included all events in which over 0.25 cm (0.1 In.) of rain fell.
A summary of these rainfall events is shown In Table 2. The cummulative
recorded rainfall during this period was 37.31 cm (14.69 in.), with the
mean rainfall equaling 1.50 cm (0.59 in.). The standard deviation of
the rainfall was 1.22 cm (0.48 in.) Indicating a high variance in rain-
fall events. A frequency histogram of the rainfall amounts is shown in
Figure 23. As can be seen, the mode class of rainfalls was the 0.66 to
1.27 cm (0.26 to 0.50 in.) range, with nine of the rainfalls occurring
in this range. The second most frequent range was the 1.30 to 1.90 cm
(0.51 to 0.75 in.) group with six of the rainfalls occurring in this
range. Twenty-two of the total rainfall events were less than 2.54 cm
(1.0 in.).
Storm lengths ranged between 0.17 and 22.2 hours, with the mean storm
lasting 3.09 hours. The duration of the storm includes the entire
time period over which any rainfall continued. Eight of the storms,
32 percent, lasted less than 30 minutes, and 19 storms, 76 percent,
lasted less than 3 hours.
A corrleation between rainfall patterns and overflow patterns was
attempted. However, no direct correlation between rainfall volume
or intensity and the resulting overflow volume or flow rate was found.
This fact lead to speculation that, perhaps, the accuracy of the over-
flow measuring devices was In question. Depth-discharge relationships
had been developed for these sewers by means of dye tests. This was
-------
Table 2. KENOSHA RAINFALL SUMMARY FOR 1970
Storm
No.
1
2
3
k
5
6
7
8
9
10
11
12
13
13B
14
15
16
17
18
19
20
21
22
23
2k
Cumulat
Mean
Rai ngauge
A
Date
6/01
6/17
6/20
6/26
7/08
7/08
7/13
7/19
7/27
7/28
7/30
8/18
9/02
9.03
9-03
9/06
9/09
9/14
9/15
9/15
9/17
9/22
9/23
9/25
10/14
ive
cm
1.85
0.00
2.16
1.65
0.69
0.13
0.94
0.76
0.76
0.19
0.89
0.94
1.35
0.71
0.25
3.02
1.83
2.82
1-19
1.12
6.10
1.32
3.28
0.61
1.27
37.08
1.47
in.
0.73
0.00
0.85
0.65
0.27
0.05
0.37
0.30
0.30
0.47
0.35
0.37
0.53
0.28
0.10
1.19
0.72
1.11
0.47
0.44
2.40
0.52
1.29
0.24
0.50
14.60
0.58
Rai ngauge
B
cm
1.60
0.51
1.78
2.29
0.89
0.76
1.12
0.69
0.64
2.67
1.27
0.94
1.40
0.51
0.25
2.92
1.98
2.34
1.68
1.14
6.43
1.14
4.10
1.14
1.27
41.43
1.65
i n.
0.63
0.20
0.78
0.90
0.35
0.30
0.44
0.27
0.25
1.05
0.50
0.37
0.55
0.20
0.10
1.15
0.78
0.92
0.66
0.45
2.53
0.45
1.61
0.45
0.50
16.31
0.65
Ra i ngauge
C
cm
1.09
1.65
0.89
2.62
0.89
0.38
0.89
0.25
0.64
1.52
0.51
0.53
1.07
0.18
0.71
2.03
1.40
1.30
1.24
1.09
5.46
1.35
2.87
0.97
0.33
31.85
1.27
i n.
0.43
0.65
0.35
1.03
0.35
0.15
0.35
0.10
0.25
0.60
0.20
0.21
0.42
0.07
0.28
0.80
0.55
0.51
0.49
0.43
2.15
0.53
1.13
0.38
0.13
12.54
0.50
Average
cm
1.55
0.58
1.73
2.08
0.90
0.41
0.99
0.61
0.69
h52
0.94
0.84
1,30
0.51
0.38
2.74
1.78
2.24
1.37
1.12
6.07
1.24
3.51
0.91
1.04
37.31
1.50
In.
0.61
0.23
0.68
0.82
0.35
0.16
0.39
0.24
0.27
0.72
0.37
0.33
0.51
0.20
0.15
1.08
0.70
0.88
0.54
0.44
2.39
0.49
1.38
0.36
0.41
14.69
0.59
-------
9
8
>-
O
2 7
UJ
D
0
UJ ft
fW W
QC
U.
iii 5
UJ
O
UJ
a: 4
or
D
U
u 3
0
2
\
Q
.
•
-
____.
i i i
.6 1.2 1.9 2.5 3.2 3.8 5.7 6.3 CM
.25 .5 .75 1.0 1.25 1.5 2252.5 IN
TOTAL RAINFALL
Figure 23. Histogram of rainfalls in Kenosha
for June 1, 1970 to October 14, 1970
-------
necessitated by the fact that the construction drawings of these sewers
were incomplete and questionable. In fact, some of the sewers were shown
to slope from the lake back towards the overflow mechanisms.
Study of the overflow data indicated that in some cases the volume of
overflow measured exceeded the volume of rainfall over the combined sewer
area. Since It was obvious that the depth-discharge relationships were
not accurate and that the overflow data was invalid, no analysis of the
data was performed. However, the data did show that for all 25 storms
recorded, there was a resultant overflow condition. The lowest recorded
rainfall was 0.38 cm (0.15 in.). Despite the lack of the accurateness
of the overflow measurements, it was obvious that the major overflow
was occurring at 67th Street. Using the depth of flow as a relative
indication of discharge it appeared that the overflows at 57th and 59th
Street were negligible relative to 67th Street.
OVERFLOW QUALITY ANALYSIS
All twenty-five rainfall events were monitored either completely or
partially for the eighteen quality characteristics listed earlier. As
explained, the sampler operated for a period of four hours after the
overflow began, or until the overflow ceased if less than four hours in
duration. If a sampler malfunctioned and did not automatically start
sampling, it would be manually triggered by personnel arriving at the
sites, and the actual period of sampling reported. When all sites
operated properly and the overflow period was of significant duration,
composite samples from the WPCP, 67th Street, and 57th Street were from
0 to k hours after the overflow began, and 59th Street was from 0 to 2
hours after the overflow began. The shortness of the sampling duration
at 59th Street is explained by the small volume and duration of overflow
at this site.
Complete results from the sampling program are given In Appendix B,
Tables Bl to B25. The data in these tables was analyzed to give an
indication of the quality of sewage to be treated by the demonstration
system. Only data from samples taken between 0 to k hours (0 to 2 hours
for 59th Street), 0.5 to 4.5 hours, or 1 to 5 hours was used. No grab
samples, or samples taken more than one hour after the specified range
were used. Table 3 contains the mean concentrations of the 18 quality
characteristics measured at each site, along with standard deviations,
and the 952 confidence Interval for the means. The magnitude of the
standard deviations indicates the high variance of overflow quality with
each storm.
The highest overall pollutional concentration during overflow was found
at the influent to the WPCP. At this location the mean values for some
of the basic quality parameters were: total solids - 938 mg/1,
suspended solids - 558 mg/1, total BOD - 175 mg/1, dissolved BOD - 31 mg/1,
-------
Table 3. KENOSHA OVERFLOW QUALITY SUMMARY FOR 1970
Parameter Units
pH
Settleable ml/1
sol i ds
Total ,.
solids mg/1
Total
volati le /,
... mg/1
solids
Suspended
solids m<3/]
Suspended
volatile mg/1
sol i ds
Total BOD mg/1
Dissolved /T
BOD mg/1
Site
WPCP
67th St.
59th St
57th St.
WPCP
67th St.
59th St.
57th St.
WPCP
67th St.
59th St.
57th St.
WPCP
67th St.
59th St.
57th St.
WPCP
67th St.
59th St.
57th St.
WPCP
67th St.
57th St.
WPCP
67th St.
59th St.
57th St.
WPCP
67th St.
59th St.
57th St.
Samples
19
14
8
9
19
12
4
6
19
14
7
9
19
14
7
9
19
14
8
9
19
14
9
17
12
6
8
15
10
4
5
Mean
7.14
7.26
7-17
7.34
10.80
3-90
5.4o
9. 10
938
486
597
898
566
255
302
436
558
280
405
590
401
147
307
175
74
96
172
31
22
30
22
Standard
deviation
0.24
0.34
0.29
0.49
6.1
2.7
3.0
6.3
391
124
170
474
326
77
108
246
346
148
170
437
287
90
235
9)
38
41
115
18
16
12
11
952
Confidence
level
7.02- 7.26
7.07- 7.45
6.92- 7-43
6.96- 7-72
7.90-13.70
2.20- 5.60
0.60-10.20
2.50-15.70
750-1126
414- 557
440- 755
534-1262
408- 723
181- 269
202- 402
247- 626
391- 724
194- 360
263- 548
254- 925
263- 538
95- 199
126- 488
128- 221
49- 98
53- 139
76- 267
21- 41
10- 33
10- 50
8- 36
-------
Table 3 (continued). KENOSHA OVERFLOW QUALITY SUMMARY FOR 1970
Parameter
Total COD
Di ssol ved
COD
Total
organ ic
carbon
Dissolved
organic
carbon
Total
inorgan ic
carbon
Dissolved
inorganic
carbon
Kjeldahl
n i trogen
Total
phosphorus
Units Site
WPCP
mg/, 67th St.
59th St.
57th St.
WPCP
67th St.
mg/1 59th St.
57th St.
WPCP
mg/1 6?th St.
59th St.
57th St.
WPCP
,, 67th St.
mg/1 59th St.
57th St.
WPCP
mg/1 67th St.
59th St.
57th St.
WPCP
mg/1 6?th St.
59th St.
57th St.
WPCP
*" K
57th St.
WPCP
mg/1 J7th St.
59th St.
57th St,
Samples
19
15
9
9
19
12
5
7
16
10
7
9
14
3
5
6
13
11
7
9
14
9
5
6
17
12
3
6
9
7
2
4
Mean
731
237
338
550
81
79
84
56
195
71
113
200
25
19
19
19
33
23
18
32
23
18
12
28
16.3
7.3
7.6
10.3
9.1
3. 1
2.4
8.9
Standard
dev iat ion
531
100
148
359
36
43
50
18
142. 1
2L9
47.2
164.2
14.7
1 1.2
3-1
6.3
10.2
10.6
5-7
H.7
9-7
6.9
5.4
9.7
5.2
3.8
4.7
5-3
6.5
w • *j
1.5
2.6
4.7
95£
Conf i dence
level
476- 988
181- 293
228- 447
274- 826
63- 98
52- 106
22- 146
39- 73
1 19- 271
56- 87
70- 157
74- 327
16. 5-33. *»
10.4-27.6
15. 1-22.8
12.4-25.6
26.8-39.2
15.9-30.1
12.7-23.3
23.0-41.0
22.4-33.6
12,7-23.3
5.3-18.7
17-8-38.2
13.6-19.0
4.9- 9-7
0-19.0 '
4.7-15.8
4.1-14.1
1-7- 4 '.5
1.4-16.4
50
-------
Table 3 (continued). KENOSHA OVERFLOW QUALITY SUMMARY FOR 1970
Parameter
Total
col i form
Fecal
col iform8
Units Site
WPCP
#/m1 67th St'
59th St.
57th St.
WPCP
-" 59th":
57th St.
Sampl es
19
14
8
9
17
13
7
8
Mean
53,000
12,990
15,670
12,590
4 300
U346
1,920
6,708
95%
Standard Confidence
deviation level
a. Geometric mean.
-------
total COD - 731 mg/1, dissolved COD - 81 mg/1, and total phosphorus -
9.1 mg/1. These characteristics are much higher in concentration than the
average dry weather flow at the WPCP- In 1970 the WPCP had an average
influent suspended solids of 123 mg/1, and BOD of 9*» mg/1. The WPCP did
not run any type of phosphorus determination at this time.
The reason for these high concentrations is best explained by the first
flush theory which includes the scouring of residual matter from the sewers
themselves. As earlier explained, the interceptor sewer leading to the
WPCP has a maximum design capacity of approximately 189,250 cu m/dav
(50 mgd), and the average daily flow to the WPCP in 1970 was only 62,301
cu m/day (16.A6 mgd). Also, the main trunk sewer with the largest contri-
bution of dry weather flow to the interceptor is the 2.51 m (99 in.) sewer
which intersects the interceptor at 67th Street. This location is in
close proximity of the WPCP, being less than 1.61 km (1 mile) north.
These two facts, low flow and location of the main trunk sewer, make
possible a high buildup of settled matter in the entire length of the
interceptor north (upstream) of 67th Street. During an actual rainfall
runoff period, the interceptor will be scoured by the increased flow with
the pollutional matter being carried to the WPCP. Only after flow to
the WPCP exceeds 113,550 cu m/day (30 mgd) is the interceptor surcharged
by means of the hydraulic gate at the WPCP inlet. When the interceptor
is surcharged it prevents the entrance of any additional sewage, and
forces all of the sewage in the trunk sewers to flow to the outfall
sewers, except for a rate equal to that entering the WPCP. Since the
interceptor has not reached capacity when the first flush from the 2.51
m (99 in.) trunk sewer occurs, a portion of the scoured material from
this sewer will also be evident at the WPCP during the first periods of
runoff.
A very encouraging and affirming indication received from this data was
the extremely low dissolved BOD to total BOD ratio. This indicated that
82 percent of the BOD was in the particulate form. This is the type of
material which is optimally removed by the contact stabilization process.
In addition to the indication of potentially good BOD removals, it was
felt that the high suspended solids concentration, which is responsible
for a high pollutional loading during overflows, should be efficiently
removed in the clarification phase of the demonstration system.
The 67th Street site, which has the largest overflow volume, had the
lowest pollutional concentration. This is due in part to a portion of
the flush of the trunk sewer being absorbed by the interceptor before
it reaches capacity. As discussed, when the interceptor does reach
capacity, the main trunk sewers overflow directly to the lake without
mixing with the interceptor contents. Thus, during rainfall runoff
periods, the overflow from 67th Street consists primarily of stormwater
runoff and presently discharged sewage. The mean values for some of the
basic parameters of 67th Street were: total solids - A86 mg/1, suspended
solids - 280 mg/1, total BOD - 75 mg/1, dissolved BOD - 22 mg/1, total
COD - 236 mg/1, dissolved COD - 79 mg/1, and total phosphorus - 3.1 mg/1.
Here again the dissolved BOD to total BOD was low, with 70 percent of the
BOD being in the particulate form.
52
-------
The overflow at 59th Street appeared to contribute the smallest volume of
overflow. The pollutions! concentration in this flow was equal or
slightly higher than that at 67th Street, The mean values were: total
solids - 597 mg/1, suspended solids - *»05 mg/1, total BOD - 96 mg/1,
dissolved BOD - 30 mg/1, total COD - 338 mg/1, dissolved COD - 85 mg/1,
and total phosphorus - 2.4 mg/1. At this location the trunk sewer
terminates at the intersection of the invert of the trunk sewer and
crown of the interceptor. The outfall sewer to the lake for use during
rainfall runoff periods is located above the trunk sewer center elevation
and thus the head of sewage must be above this level before overflow
will occur. This reason along with the small area served accounted for
the apparent small amount of overflow. At this site the most frequently
occurring overflow period was 0 to 2 hours, while at the others it was
0 to k hours.
The 57th Street overflow had the highest pollutional concentration of the
three outfall sites. The volume of overflow at this location was estimated
to always be larger than at 59th Street, but never approached the apparent
magnitude of 67th Street. The overflow mechanism at this location is
identical in form to that of 67th Street, The reason for the higher
pollutional concentrations is not fully understood. Possible contributing
factors include the fact that the dry weather flow in this trunk sewer
contains a high amount of industrial wastewaters which may contribute to
the high suspended solids and BOD concentration. Also, a great portion
of the stormwater runoff comes from the highly urbanized downtown area
which has a high coefficient of runoff and a high amount of surface
contaminants. The mean values at this location were: total solids -
898 mg/1, suspended solids - 590 mg/1, total BOD - 172 mg/1, dissolved
BOD - 22 mg/1, total COD - 56 mg/1, and total phosphorus - 8.9 mg/1.
From the results of the data analysis on the overflow quality it was felt
that the original hypothesis for the implementation of a high rate
biological adsorption process for treating combined sewer overflow had
been affirmed. Other conclusions from this phase of the project included:
1. Qualitative proof that the pollutional load caused by combined
sewer overflow to Lake Michigan was significant.
2. The oxygen demanding materials, based upon the BOD and COD tests,
were found to be almost 80 percent in the particulate form. This
is the type of material which the biosorption system is designed
to remove at very high efficiencies.
3. By reducing the volume of combined sewer overflow, and thus the
suspended solids and collform loadings, the incidence of closing
the Kenosha public beaches on Lake Michigan should be greatly
reduced.
4. A plan for accurate flow measurement of the remaining combined
sewer overflow had to be implemented during operation of the
demonstration system to determine the amount of untreated overflow
still occurring, and to determine if there is unused capacity
within the interceptor.
53
-------
SECTION VII - EVALUATION PROGRAM AND RESULTS
PLAN OF OPERATION
The evaluation program to determine the effectiveness of the demonstra-
tion system as an alternative to combined sewer separation was conducted
between April 12, 1972 and October 1, 1973- The program was divided
Into three general portions. These were 1) determine if the concept of
using the contact stabilization process on a periodic basis was feasible,
2) If the process was feasible, what was the optimum range of operation
for the various process variables, and 3) how effective was the
75,700 cu m/day (20 mgd) system In reducing the volume of combined
sewer overflow when operated at maximum flow rate conditions. It was
not possible to complete the above three tasks simultaneously. For
Instance, during the first portion of the study program when the feasi-
bility of the process was being studied, the process variables were
held within the normal range of operation commonly associated with the
contact stabilization process as much as possible. During the second
portion of the study when the variables were tested over a wide range
of values, it was often necessary to run the system much below the
75,700 cu m/day (20 mgd) design rate in order to examine longer contact
and reaeration times and higher mixed liquor concentrations. In
addition, for the majority of the evaluation program the demonstration
system was not started until Envirex Inc. employees had arrived from
Milwaukee at the WPCP.
For purposes of determining the treatment efficiency of the demonstration
system a thorough sampling and laboratory analysis program was developed.
Samples were taken at the effluent end of the grit tank, from the contact
tank, from the stabilization tank, from the Parshal 1 flume at the
demonstration system final clarifler, and from the Parshal1 flume at
the dry weather clarifler. Table 4 indicates the sample location and the
characteristics measured. The laboratory analytical techniques used are
described in Appendix A.
Process variables for study during the evaluation program Included MLSS
concentration, contact time (based on total hydraulic flow), reaeration
time, and stabilization time. The purpose of running the system at
different values for the above parameters was to determine the range
of satisfactory operation, the results of which would be useful in
future designs, and to determine if there were specific values at
which system operation was unsatisfactory. Listed below are the
process variables for study and the intended ranges of operation.
-------
Table
SAMPLING POINTS AND ANALYSES PERFORMED
Characteristics Measured
pH
Settleable sol ids
Total sol i ds
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Total Kj el da hi nitrogen
Total phosphates as P
Total col i form
Fecal col i form
COD
Grit Contact
tank tank
X X
X
X
X
X X
X X
X
X
X
X
X
X
X
X
x (1973)
Sample location
Dry
Stabilization Final weather
tank clarifier clarifier
X X
X
X
X
X XX
X XX
X XX
X
X X
X
X
X
X
X
x (1973)
x = analyses performed
-------
VARIABLE UNIT OF MEASURE RANGE FOR STUDY
MLSS Concentration mg/1 500-5,000
Contact Time minutes 10-30
Reaeration Time hours 1~7
Stabilization Period days >0-15
The other parameters of operation whicti were to be determined each time
the demonstration system was used are listed below.
Volume Treated
Average Flow Rate
Average Sludge Transfer Rate
Transfer Rate as a % of Raw Flow
F/M Ratio
Air Supply
Stabilization Tank Turnovers
Clarifier Surface Overflow
Clarifier Detention Time (based on total flow)
Clarifier Turnovers
Clarifier Solids Loading
No specific number of system runs or rigid factorial experimentation
procedures were developed for the evaluation program. Instead, it was
planned to use the system as many times as necessary until the removal
efficiencies being achieved were consistent and statistically valid. The
evaluation of the process variables would be carried out in a random
fashion until it was evidenced that certain operating values of specific
variables significantly affected process performance.
METHOD OF OPERATION
When it appeared that a rainfall event was imminent, or when a rain began,
personnel at the WPCP would telephone Envirex Inc. or the home of
designated Envirex employees and inform them of the possible demonstration
system run. Travel time from Milwaukee to the Kenosha WPCP averaged one
hour. Also, an additional off-duty WPCP operator would be called in.
Not until Envirex personnel arrived at the WPCP would the demonstration
system be started. This procedure was continued during all of 1972.
However, during 1973 the operating personnel at the WPCP had become
familiar enough with the equipment to start the system themselves after
notifying Envirex personnel. Although the demonstration system had
provisions for automatic start-up, this feature was never used. It
could not be used In 1972 since operation of the system was delayed until
Envirex personnel arrived, and in 1973 the WPCP would start the system
in anticipation of the high flow rates before these rates actually
occurred.
56
-------
For all runs, except when a test was being conducted at a specific flow
rate, or when mechanical problems with the raw flow pump developed, the
rate of flow for treatment by the demonstration system occurred in the
following manner. A wet well is located below the pump room at the
Kenosha WPCP. Flow from the interceptor sewer passes through the
comminutors directly into this basin. The raw flow pumps (including the
demonstration system pump) are paced off of this level. When the level
exceeds 1.13 m (3-7 ft) in depth the pumps are running at maximum capacity
and It is necessary to begin closing the hydraulic gate at the entrance
to the WPCP. This gate is held in a partially closed position until the
level begins to drop, at which time the gate is opened. As the wet well
level drops, the pumps are automatically throttled down to lower pumping
rates.
Although provisions were made to allow the demonstration system to treat
only the flow in excess of 87,055 cu m/day (23 mgd), the system was not
run in this manner. Instead, the demonstration system was run in
parallel with the DWP. This meant that when flows to the WPCP exceeded
the DWP capacity, the demonstration system would be started and the
entering flows would be split about equally between the DWP and demon-
stration system.
At maximum flow periods of 162,755 cu m/day (J»3 mgd), 87,055 cu m/day
(23 mgd) would be going to the DWP and 75,700 cu m/day (20 mgd) to the
demonstration system. As the flow to the WPCP began to decrease, say to
113,550 cu m/day (30 mgd), approximately 56,775 cu m/day (15 mgd) would
be going to each system. When the total incoming flow was reduced to
87,055 cu m/day (23 mgd) the demonstration system was then taken out of
service and the total 87,055 cu m/day (23 mgd) went to the DWP (which
now made use of the demonstration system final clarifier).
Sampling of the process was done by a combination of manual and automatic
sampling. Automatic samples were located at the grit tank, contact tank,
and demonstration system final clarifier. At the beginning of a run a
sample would be manually taken from the grit tank and then automatically
every half hour afterward. The sample was drawn from the effluent trough
of the grit tank which fed a 91. M cm (36 in.) diameter conduit leading
to the contact tank. After the demonstration system was taken out of
use, the samples were proportioned according to the raw flow rate at
the time of sampling. The automatic sampler at the contact tank would
be started while the tank was filling and would sample every 30 minutes.
The samples were composited on an equal volume basis. The sample was
taken at one end of the contact tank just Inside the overflow weir,
approximately 0.30 m (I ft) below the surface. The automatic sampler at
the final clarifier would take Its first sample approximately k$ minutes
after the system started, and then every 30 minutes thereafter. The
sample was drawn from the side of the flume, approximately 0.61 m (2 ft)
upstream of the beginning of the throat. The samples were composited in
the same manner as the grit tank samples.
57
-------
Manual samples were taken at 30 minute intervals for the transferred
sludge from the stabilization tank. A tap was located on the discharge
pipe from the transfer pump from which an equal volume of sample was
drawn and composited. The manual sampling of the dry weather final
clarifier during operation of the demonstration system was done at 30
minute intervals also. The samples were drawn from the throat of the
Parshall flume and composited on an equal volume basis.
The automatic samplers were built specifically for the project by Envirex.
The sampler intakes consisted of a 0.30 m (1 ft) section of 1.27 cm
(0.5 in.) diameter pipe with 0.64 to 0.95 cm (0.25 to 0.375 in.) holes
drilled in the pipe. The intake was connected by garden hose to a
positive pressure pump having a flow rate of about 0.19 I/sec (3 gpm)
at a suction lift of 4.57 m (15 ft). A sample distributing arm rotated
in a 360° circle depositing samples in 2k separate one liter plastic
bottles. The time between samples could be varied between 3 to 60
minutes. The actual pumping cycle would only take three minutes with
the lines first being purged followed by the filling of the sample
bottles and then a final purging. The samplers were enclosed in wooden
frames. A photograph of a typical sampler is shown in Figure 24.
CONTROL PANEL
SAMPLE DISTRIBUTION
ARM
PUMP
Figure 2k. View into typical sampler constructed
for use in conjunction with the demonstration system
58
-------
At the end of a run the samples would be transported to the laboratories
in Milwaukee. If the samples were brought to the laboratory on any day
between the hours of 7 am and 7 pm analyses would begin on all samples
immediately. If the samples were brought in between 7 pm and midnight,
the pH would be measured and the BOD and coliform analyses started. The
remaining sample would be refrigerated until the following morning. If
the samples were brought in after midnight they would be refrigerated
until the following morning when all the analyses would be started.
Problems with the automatic flow rate controlling equipment persisted
throughout the entire project. During 1972 it was impossible during
dry weather to balance the WAS flow rate into and out of the stabiliza-
tion tank. As a result, the stabilization times were actually the
length of time the sludge was held In the stabilization tank between
runs. During 1973 the flow balancing equipment worked periodically.
When it was working, the stabilization time was based on a dynamic condi-
tion, where sludge was continually being fed into and taken out of the
tank, and the stabilization time was calculated as the hydraulic
detention time.
Problems controlling the RAS rates and sludge transfer rates during use
of the demonstration system also occurred. It was determined that the
sludge transfer rates were being properly paced as a percentage of the
raw flow, but that the RAS rates to the stabilization tank were not.
This was overcome by setting the RAS controller in the manual mode of
operation and continuously setting the rate to correspond with the
sludge transfer rate.
The air supply controller to the contact tank also operated erratically.
Therefore for the majority of the runs the air supply was controlled
manually and usually set at a rate of 52.5 to 56.0 cu m/min (1,875 to
2,000 cfm) which proved to be sufficient for good mixing and satisfactory
removals.
It was fortunate that it was possible to override the automatic
controllers by placing the malfunctioning equipment in the manual mode
of operation. This prevented having to shut the system down for repairs
or abandoning the various aspects of the evaluation program. However,
operating the equipment in the manual position put an added burden and
mental strain on the operator who had to continually check flow rates
to ensure that all flow rates were in proper balance.
The provision for borrowing sludge from the DWP was never necessitated.
During every run there was a sufficient volume of sludge in the
stabilization tank when the system started up to provide a sufficient
reaeration time during operation.
Although eight aerators were present in the stabilization tank, only
six were used for the majority of the runs in 1972, and only four in
1973. During dry weather, only A aerators were used in 1972 and only
59
-------
2 aerators In 1973. Measurement of DO levels and calculation of oxygen
uptake rates (OUR) indicated that this amount of aeration was sufficient.
This is further discussed later in this report.
A total of **9 runs occurred during the evaluation program, In this period
over 681,300 cu m (180,000,000 gal.) of potential overflow were treated
and sampled during 278 hours of operation. The demonstration system was
operated from April 12, 1972 thorugh August 17, 1972, at which time it
was forced out of service because the raw flow pump associated with the
demonstration system was being used by the DWP while its 75,700 cu m/day
(20 mgd) raw flow pump underwent extensive maintenance. The system was
put back into operation during the later part of October and then taken
out of service permanently for the winter on November 6, 1972. The system
was put back into operation during the week of March 19, 1973 and
operated until October 1, 1973. Only the times when Envirex personnel
were present and sampling was use of the system considered a run. There
were times during the two year evaluation period when the WPCP used the
system during dry weather to relive high flow conditions in the sewers.
Also, the system occasionally was operated for a period of time by WPCP
personnel after sampling had stopped in order to draw the hydraulic grade
in the interceptor down to a low level. However, these uses of the system
were not recorded as part of the evaluation program. Data tables from
all k$ runs are contained in Appendix C, Tables C-l to C-^9- These tables
contain all pertinent operating circumstances, laboratory data, and
removal efficiencies. Following is an analysis and discussion of this
data.
FEASIBILITY STUDY
After the first 19 runs of the demonstration system, between April 12 and
August 16, 1972, it was felt that the system had proven that the concept
of using the contact stabilization process on a periodic basis was
feasible. During these 19 runs no attempts were made to determine the
conditions under which performance would not be satisfactory. Instead,
the process operating values were kept within conservative limits and
emphasis was placed on achieving good removal efficiencies. Sludge
transfer rates varied between 25-55% of the raw flow, contact times were
12.1 to 19.6 minutes based on total flow, and reaeration times ranged
from 1.0 to 3.08 hours. Because the stabilization time during this
period was actually mandated by the time between storms, stabilization
periods of up to 15 days were experienced. Actual operating conditions
can be found in Appendix C. The ranges of operation for various process
variables from runs 1-19 are listed in Table 5.
A total of 277,062 cu m (73,200,000 gal.) were treated during these first
19 runs. The weighted mean concentrations for the raw flow and effluent
samples are given in Table 6. The removals achieved, 93% for suspended
solids, 83% for total BOD. and 81% for TOC were equal to what had been
60
-------
Table 5. RANGES OF OPERATION, RUNS NO. 1-19
Operating variable
Range
CTN
Volume treated
Average flow rate
Sludge transfer percentage
MLSS
Contact time
F/M
Stabilization time
Reaeration time
Surface overflow rate
Clarifier solids loading
6,805-28,607 cu m (1.798-7.558 mg)
52,233-73,429 cu m/day (13.3-19.A mgd)
25-55
975-5,370 mg/1
12.1-19.6 minutes
0.64-5.25
0.5-15.0 days1
1.0-3.08 hours
35.3-51.3 cu m/day/sq m (864-1,256 gpd/sq ft)
56,120-363,560 g/day/sq m (11.5-74.5 Ib/day/sq ft)
1. Static conditions
-------
Table 6. OPERATING RESULTS, FIRST 19 RUNS
Parameter
Suspended sol i ds
Suspended volatile solids
Total sol ids
Total volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total Phosphate as P
Parameter
Total col i form
Fecal col iform
1. Raw sample taken after gri
2. Final samples taken prior
Units
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
Units
#/ml
#/ml
t tank.
to chlori
Weighted mean
raw
concentration
332
144
696
269
10?
25
117
23
11.6
4.8
Geometric mean
raw
concentration
26,632
2,006
nation.
Weighted mean
final
2
concentration
24
14
458
141
18
8
22
17
6.2
2.6
Weighted mean
f i nal
2
concentration^
2,416
450
Percent
removal
93
90
34
48
83
68
81
26
47
46
-------
anticipated and were considered satisfactory. Even higher percentage
removals could have been achieved if the raw sample had been taken
prior to grit removal and the final sample taken after chlorinatlon.
A grab sample of the raw flow to the grit tank during Run No. 1»3 had
a suspended solids concentration of 517 mg/1. The effluent sample had
a concentration of 38? mg/1, indicating a removal of 130 mg/l across the
grit tank. However, since the project objective was to measure the true
efficiency of the contact stabilization process in treating potential
combined sewer overflows, sampling was done at the specified locations.
STUDY OF PROCESS VARIABLES
Of the next 30 runs, 18 were conducted under test conditions to determine
what operating conditions would not produce satisfactory results. Also,
the ability of the system to perform for long durations of time was tested.
After Run No. 31 was completed the demonstration system was left running
for a total of 108 hours. Twice during this period the system was
sampled to determine treatment efficiency. These sampling periods
constitute Runs No. 32 and 33- Run No. 37 was similar, with the system
running a total of 58 hours. Two sampling periods during this duration
constituted Runs No. 38 and 39.
Listed below are the test runs and a description of the test conditions
for each run. Complete operating conditions can be found in Appendix C.
Run No. Test Conditions
20 Low sludge transfer percentage to obtain low MLSS
concentration and long reaeration time.
21 Low sludge transfer percentage to obta-in low MLSS
concentration and long reaeration time.
22 Only one contact tank compartment to obtain shorter
contact time; treated primarily dry weather flow.
23 Treatment of dry weather flow only; no rainfall.
27 High sludge transfer percentages to obtain high MLSS
concentration.
28 Low sludge transfer percentage to obtain low MLSS
concentration and long reaeration time.
29 Only one contact tank compartment to obtain a shorter
contact time.
30 Only one contact tank compartment and a low sludge transfer
percentage to obtain a short contact time, a low MLSS
concentration, and a long reaeration time.
-------
No. Test Conditions
31 Only one contact tank compartment, a high sludge
transfer percentage to obtain a short contact time,
a high MLSS concentration, and a short reaeration time.
32 High sludge transfer percentage to obtain a high MLSS
concentration and a short reaeration time. This was a
continuation of run No. 31, sampling took place from
39.2 to 43.2 hours after the start of Run No. 31.
33 High sludge transfer percentage to obtain a high MLSS
concentration and a short reaeration time. This was a
continuation of Run No. 31, sampling took place from
87.2 to 90.7 hours after the start of Run No. 31.
34 Low sludge transfer percentage to obtain a low MLSS
concentration and a long reaeration time. Only one
contact tank compartment to obtain a shorter contact
time.
35 Only one contact tank compartment to obtain a shorter
contact time.
37 This was essentially a run under normal conditions,
however, it began another long duration run.
38 This was an extension of Run No. 37 with sampling
taking place from 5.8 to 10.6 hours after the start
of Run No. 37.
39 This was an extension of Run No. 37 with sampling
taking place from 56.2 to 58.6 hours after the start
of Run No. 37-
^° High sludge transfer percentage to obtain a high MLSS
concentration and a short sludge reaeration time.
^' High sludge transfer .percentage to obtain a short
reaeration time.
^2 High sludge transfer percentage to obtain a high MLSS
concentration. Only one contact tank compartment
to obtain a short contact time.
-------
It is obvious that since the return sludge transfer is set as a percentage
of the raw- flow, a change in the raw flow rate automatically changes the
reaeration time and contact time. This point exemplifies one of the basic
problems encountered during the test program. Almost all of the process
variables were interrelated, and changing one operating condition caused
many others to be changed. For instance, at a constant flow rate, if it
were desired to see the effect of a higher MLSS concentration the return
sludge ratio would be increased. However, in addition to increasing
the MLSS concentration, the contact time would be shortened, the
reaeration time would be shortened, and the solids loading on the final
clarifier would be increased.
The removal efficiency data from the test storms was studied following
completion of the test program and Runs No. 20, 21, 23, 28, 30 and 34 and
42 were found to have unsatisfactory performance. Effluent concentrations
of greater than 30 mg/1 suspended solids or BOD were nominally chosen
as the cutoff point for satisfactory performance. Of the seven runs
which produced unsatisfactory results, five of the runs had basic
similarities. Runs No. 20, 21, 28, 30 and 34 all had sludge transfer
percentages of less than 20% and MLSS concentrations of 2100 mg/1 or less.
All five had reaeration times greater than four hours, as compared to the
mode reaeration time of 1 to 3 hours for all runs. This is an example
of the interdependence of the process variables since the low MLSS
concentrations are a result of low sludge transfer percentages which
cause the long reaeration times unless a very small volume of sludge is
present in the stabilization tank.
The reason for the poor performance during Run No. 23 was attributed to
a period of solids washout in the final clarifier. The raw flow pump
was allowed to pump at maximum capacity (approaching 94,625 cu m/day
(25 mgd)) resulting in SOR's of 65-3 cu m/day/sq m (1600 gpd/sq ft) and
solids loadings of over 366,000 g/day/sq m (75 1b/day/sq ft) based upon
the average MLSS concentration. When the flow rate was reduced below
75,700 cu m/day (20 mgd) the effluent quality improved, however, the
effluent composite sample included the high suspended solids concentra-
tion during the washout period.
The unsatisfactory results from Run No. 42 were due to a poor settling
sludge that plagued the DWP and demonstration system during the later
part of 1973- The poor settling characteristics of the sludge were
evidenced by the DWP laboratory results which showed poorer removal
percentages beginning in June 1973 when compared to 1972 and sludge
volume indices well above 100. This forced the DWP to keep flow rates
to the secondary plant during dry weather under 75,700 cu m/day (20 mgd)
to prevent solids washout. Run No. 40 in June 4, 1973 saw a solids
washout of the DWP clarifiers when the demonstration system went into
operation. The same problem occurred during Runs No. 41, 42, 43, 44,
47 and 48. During Runs No. 42, 44, 47 and 48 solids washout occurred
from the demonstration system final clarifier also. After the
65
-------
demonstration system was put Into operation the DWP clarlfiers would
produce good quality effluent for up to two hours before washout would
occur. The demonstration system would usually begin washing out after
about three hours. These occurrences point out the high degree of
dependence that the demonstration system has on the quality of sludge
being produced In the OWP- The relationship of the DWP and the demonstra-
tion system is further discussed later.
The two tests of extended continuous use of the demonstration system,
Runs No. 31, 32, and 33, and Runs No. 37, 38 and 39» were performed to
determine the ability of the system to perform over long periods of
time. This was important to determine since this system may eventually
find application in a storage/treatment scheme where the bulk of the
overflow will be held in storage and fed back to the treatment process
over a long period of time. The efficiency of the system as the duration
of operation continued Is shown below.
Run Hours into Eflfuent Percent Effluent Percent
No. Operation SS. mg/1 Removal BOD, mg/1 Removal
31 0-6 27 76.5 12 77.3
32 39.2-43.2 17 81.5 7 87.2
33 87.2-90.7 17 81.5 II 85.5
37 0-2.5 26 92.6 17 81.3
38 5.8-10.6 21 89.1 16 92.5
39 56.2-58.6 22 85.! 15 86.0
The consistency of effluent concentration throughout the entire duration
of these runs is an encouraging indication as to the system's ability to
generate a high quality viable sludge when operated for long periods.
OPTIMUM TREATMENT CONDITIONS
The results from the tests concerning the process variables had only
indicated that at low MLSS concentrations (<2100 mg/1) and high reaeratlon
times (>k hours) process efficiency may falter. However, during the
evaluation period the condition of the sludge in the stabilization tank
was constantly studied during dry weather periods between demonstration
system runs. The main purpose of the sludge study was to see if the
degradation of the physical properties of the sludge in the stabilization
tank could be used to determine the maximum stabilization time. Section
VIII contains a description and discussion of these studies. One of the
conclusions drawn from the sludge studies was that 5 days appeared to
be the maximum stabilization time before the viability of the sludge
became questionable.
66
-------
To further examine the validity of choosing the optimum ranges of
operation based upon visual Inspection of the data, step-wise regression
analysis was carried out. Data from Runs No. 23, k2t M, kj and 48
was omitted, since these were the runs during which solids washout
occurred. Run No. **9 was not included since the laboratory data was
not available at the time of analysis. Although none of the regression
indicated very good correlations, the step-wise regression technique did
show which independent variables had the most significant effect on the
dependent variables. Table 7 contains a list of the variables used, the
independent and dependent variables, the resultant equations showing the
significant independent variables in order of importance, and the multiple
correlation coefficients.
Table 7- RESULTS OF STEP WISE REGRESSION ANALYSIS
Variable Name Number
Effluent BOD concentration, mg/l 1
Effluent SS concentration, mg/l 2
Percent BOD removal 3
Percent SS removal 4
Raw BOD concentration, mg/l 5
Raw SS concentration, mg/l 6
F/M ratio 7
Stabilization time, days _ 8
Surface overflow rate, gpd/ft 9
Reaeration time, hours 10
Dependent Variable Independent variables
1 5,7,8,9,10
2 6,7,8,9,10
3 5,7,8,9,10
k 6,7,8,9,10
Equation Multiple correlation coefficient
1 - 1.60(7) + 0.92(8) + 9.1 0.670
2 = 2.^3(10) + 1.83(7) + 13-9 0.5M»
3 = 0.081(5) - 1.0(8) - 1.3(7) + 80.6 0.745
k = 0.02(6) - 0.97 (10) - 0.7(7) + 87.1 0.691
67
-------
The resultant equations do indicate that as the F/M ratio, stabilization
time, and reaeration time increase, the effluent concentrations increase
and the percentage removals decrease. The indication that percentage
removals of BOD and suspended solids are most significantly influenced by
raw concentrations may mean that the system has a constant effluent level
that it can attain and is not altered by higher or lower raw concentrations,
Based upon the test storms, the sludge studies, regression analysis, and
personal operating experience, ranges of variable operation were chosen
as being acceptable for satisfactory performance by the demonstration
system. These values are given in Table 8.
Table 8. OPERATING VALUES FOR SATISFACTORY PERFORMANCE
Operating variables
MLSS concentration
Reaeration time
Stabil ization time
Contact time
Units
mg/1
hours
days
minutes
Value
>2100
l-*f
15
> 10
Although an optimum contact time range was not specifically determined,
it is obvious that any time below 10 minutes would probably not provide
sufficient mixing. It can be assumed from the discussion in Section V
on contact stabilization process theory and from general knowledge of
the activated sludge process that longer contact times will provide for
additional removal of the soluble organics present. However, since the
purpose of the contact stabilization process is to reduce the size of
aeration facilities, and since satisfactory organic removals were achieved
under those conditions, contact times greater than 20 minutes are not
warranted in this application.
Oxygen supply, like contact time, was not found to have a limiting
minimum value in either the contact tank or stabilization tank. Air
supply rates as low as 4.4 cu m/kg BOD applied (72 cu ft/lb BOD applied)
in the contact tank, and theoretical oxygen transfer rates as low as
227 kg/hr (500 Ib/hr) in the stabilization tank during system operation
resulted in satisfactory performance. The maximum OUR measured in the
stabilization tank during system operation was 152 kg/hr (335 Ib/hr) and
during the stabilization period between runs it was 157 kg/hr (340 Ib/hr).
This made is possible during the evaluation program to reduce the number
of aerators to 4 during operation and to 2 during periods between operation.
It is estimated that an air supply rate of 56 cu m/min (2,000 cfm) to
the contact tank and a theoretical oxygen transfer supply fo 250 kg/hr
(550 Ib/hr) are sufficient to guarantee satisfactory performance at
Kenosha. The volume of sludge needed to be stored in the stabilization
68
-------
tank between runs is only that needed to provide a reaeration time of at
least one hour when the demonstration system goes into operation.
Therefore, if it is assumed that the raw flow rate will be 75,700 cu m/
day (20 mgd) and a sludge transfer rate of 40%, or 30,280 cu m/day
(8 mgd), will be used, the needed sludge volume for one hour of reaeration
would be 1,270 cu m (333,000 gal.). At flow rates less than 75,700 cu m/
day (20 mgd) or transfer rates less than 40%, the resulting reaeration
time would be longer than one hour.
Using the design criteria in Table 8, the 49 demonstration system runs
were scanned to determine which ones fell within those operating ranges,
excluding the runs when solids washout occurred. Thirty of the runs
satisfied the above conditions. These were Runs No. 2, 3, 8, 9, 11, 12,
14-17, 19, 24-27, 29, 31-33, 35-41, 43, 45, 46, and 4g. The results of
these runs were compiled in order to determine what type of performance
can be expected from the demonstration system while being operated within
the acceptable levels. Shown in Table 9 are the arithmetic mean raw and
final concentrations, arithmetic mean percent removals, and ranges of
values encountered. These runs represent a treated volume of 403,102
cu m (106,500,000 gal.) and 163 hours of system operation. The mean
effluent vales and mean percentage removals represent the degree of
treatment that can be expected from operation of the demonstration system.
RELATIONSHIP TO DRY WEATHER PLANT
A most important aspect of the project was to determine the effect of
the demonstration system on the DWP- This effect was measured in two
ways. The first was to calculate the improvement in DWP performance
because of the additional facilities available during dry weather. The
second was to determine if the DWP would be upset due to the drastic
changes in flow that the DWP would experience when the demonstration
system was put into and taken out of service.
Use of the demonstration system final clarifier by the DWP was continuous,
except when the demonstration system was treating potential combined
sewer overflow. The surface area of the new final clarifier, 1,431 sq m
(15,400 sq ft) is equal to 901 of the total surface area of the three
DWP final clarifiers. Therefore, during dry weather the flow is split
with approximately 50% of the flow going to the new clarifier and 50% to
the three other clarifiers. This increased clarification area signifi-
cantly reduced the SOR and increased the final settling times. Table 10
contains a comparison of effluent quality data from 1970, the last full
year without the extra clarifier, and 1972, the first full year with the
clarifier. Although the average secondary flow rate increased from
61,697 cu m/day (16.3 mgd) to 73,808 cu m/day (19-5 mgd), the SOR's
decreased by 371 and the removal efficiencies for BOD and suspended
solids increased by 15% and 37%, respectively.
-------
Table 9- PERFORMANCE FOR 30 RUNS AT ACCEPTABLE OPERATING LEVELS
Ari thmet ic
Parameter Units mean
Suspended sol ids
Suspended volatile solids
Total sol i ds
Total volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphate as P
Parameter
Total col iform
Fecal col iform
a. Raw samples taken from
b. Final samples taken pr
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
gri
ior
299
148
685
252
119
31
117
29
13.70
4.64
Units
#/m1
#/ml
t tank.
to chlorinat
Raw
Fina
Ari thmet ic
Range mean
92- 920
50- 337
483-1265
103- 650
44- 383
5- 65
43- 295
9- 51
6.55-22.00
1.92-12.04
ion .
23
13
464
130
16
7
23
15
7,6 2
1 .8 0
Raw
geometric
mean
31,038
2,238
1
Percent removal
Arithmet
Range mean
7- 66
0- 54
360-631
75-185
4- 38
1- 21
14- 41
5- 31
.70-12.50
.46- 4.95
90.4
90.0
29.2
41.6
84.8
72.1
76.5
39.7
43.7
58.6
1 C
Range
80.2-97.3
76.7-100.0
0.0-64.7
0.0-78.7
64.5-89.8
20.0-96.6
46.7-91.2
5.3-83.3
12.6-63.5
0.0-86.0
Final
geometric
mean
3,726
443
-------
Table 10. EFFECT OF DEMONSTRATION SYSTEM
CLARIFIER ON KENOSHA WPCP PERFORMANCE
Parameter 1970 1972
Average secondary 61,696 cu m/day 73,808 cu m/day
flow rate (16.3 mgd) (19.5 mgd)
Average surface 39.1 cu m/day sq m 2k.7 cu m/day/sq m
overflow rate (958 gpd/sq ft) (605 gpd/sq ft)
Percent BOD removal 82 9*»
Effluent BOD concentration, 17 6
mg/1
Percent suspended solids 6A 88
removal
Effluent suspended solids M 15
concentration, mg/1
Another advantage of the demonstration system final clarifier being
integrated into the DWP is the allowance of more frequent and lengthy
maintenance and cleaning of the DWP clarifiers. Before the new clarifier
was added, taking one of the clarifiers out of service would cause
hydraulic overloads on the two other clarifiers and in some cases cause
bypassing. However, the new clarifier allows up to two of the DWP
clarifiers to be out of service at one time without any change in normal
operating procedure. Also, the 9^,625 cu m/day (25 mgd) raw flow pump
affords the same flexibility in operation to the pumping plant as the
clarifier does to the rest of the plant. The value of the additional
pump was best exemplified during the period in 1972 when the DWP's
75,700 cu m/day (20 mgd) raw flow pump became inoperative and had to be
taken out of service for repair and extensive maintenance.
At the onset of the evaluation program there was great concern over the
effect of doubling the hydraulic flow to the three DWP clarifiers within
minutes after the demonstration system went into operation. Typical
circumstances would have a dry weather flow of 75,700 cu m/day (20 mgd)
being split with 37,850 cu m/day (10 mgd) going to the new clarifier
and 12,A90 cu m/day (3.3 mgd) to each of the DWP clarifiers. This
would result in a SOR of 2*»J cu m/day/sq m (590 gpd/sq ft) in the DWP
clarifiers. When a run began, a total flow of up to 87,055 cu m/day
(23 mgd) could be shifted to the DWP clarifiers if the demonstration
71
-------
system was also running at capacity. This would increase the SOR to
55.1 cu m/day/sq m (1350 gpd/sq ft) and more than double that solids
loading on the clarifiers.
During Runs Mo. 1, 2, and 3, the DWP clarifiers were upset when the
demonstration system was put into operation. Examination of DWP opera-
tional data revealed that the DWP was carrying an MLSS concentration of
5,000-6,000 mg/1. The DWP then reduced the MLSS concentration to 3,000
mg/1 and the DWP clarifiers were no longer upset when the demonstration
system went into operation. This condition lasted until the later part
of 1973 when the poor settling sludge caused problems. Effluent quality
from the DWP during operation of the demonstration system is given In
Appendix C. Of the remaining 20 runs in 1972, Runs No. 4-23, DWP clarifier
data was taken for all runs except Run No. 17- During these 19 runs the
DWP clarifier sampled had an average suspended solids and BOD concentra-
tion of 15.3 mg/1 and 17-3 mg/l, respectively.
At the time of this report the reasons for the poor settling quality of
the DWP sludge have not been fully determined. However, there were some
DWP operating differences between 1972 and 1973- In January of 1973
pickle liquor (FeSO/j) addition to the primary sedimentation effluent began
in an effort to improve phosphorus removal. In July, addition of a
non-ionic polymer to the mixed liquor feed channels was started. The
polymer was added in an attempt to improve the settling characteristics
of the sludge which had gradually deteriorated during the year. During
the first three months after polymer addition began no significant
improvement in settling characteristics was apparent. Whether the addition
of pickle liquor was the cause of poor settling is not known, however,
the effect of the poorer settling sludge is readily apparent from the
solids washouts that occurred in both the DWP and demonstration system
clarifier periodically during 1973. What this points out is the fact
that the effectiveness of the demonstration system process is directly
dependent upon the quality of sludge being produced by the DWP. It is
the DWP sludge which is wasted to the stabilization tank to provide
the needed source of biological solids when the demonstration system
begins operation. Only after the demonstration system has been operated
for many hours will the stabilization tank have completed enough turnovers
so that the sludge in use is actually that produced by the demonstration
system. Therefore, the general statement can be made that future
applications of this process can only be expected to perform to a degree
directly proportional to that of the treatment plant that they are
integrated wi th.
Another concern of the evaluation program regarding the effect on the DWP
was the disposition of the sludge being produced by the demonstration
system. However, at no time durinq the evaluation program did the
extra sludge being produced cause a problem. As a matter of fact,
tracing of the solids proved to be difficult. Assuming that an average
run would treat 13,248 cu m (3.5 million gal.) removing 3,977 kg (8,760
Ibs) of suspended solids and producing another 663 kg (1,460 Ibs) of
72
-------
solids, these extra solids could easily be absorbed by the demonstration
system without any noticeable changes. For instance, if it is assumed
that the volume of sludge in the bottom of the clarifier and in the
stabilization tank does not change during a run, the additional solids
will increase the sludge concentration by only 1,200 mg/1. Considering
that the RAS and stabilization tank sludge concentration is usually above
10,000 mg/1, this amount is not significant. If it is assumed that the
sludge concentration does not increase, but that instead the sludge
blanket in the clarifier increases in depth, this increase would amount
to only 0.32 m (1.06 ft) assuming a ]% sludge concentration.
If the sludge concentration does increase in the stabilization tank and
in the clarifier blanket, these extra solids will eventually end up at
the sludge thickening facilities by way of being pumped from the stabili-
zation tank. However, during the stabilization period some of the new
formed solids will be destroyed by aerobic digestion (see Section VIII).
Even if no solids destruction occurred, the increased loading on the
thickeners would only amount to 465 kg/day (1,025 Ib/day) at a WAS rate
of 378 cu m/day (100,000 gpd). If the result of the extra solids is an
increase in sludge blanket depth, normal DWP operating procedure would
call for an increase in the WAS rate over the next few days until the
blanket was back down to normal level. In either of the above cases
it is apparent that, although extra solids are produced by the
demonstration system and must be disposed of, the method of delivering
the solids to the thickening facilities in a continuous manner over a
period of days prevents any sludge handling problems.
Some indication of where the solids do go was given by the two periods
of long duration, continuous operation of the demonstration system,
Runs No. 31-33, and 37~39. In both of these events the solids
concentration in the stabilization tank increased significantly from
the first hours of operation until the end of operation. An increase
from 11,400 mg/1 to 14,600 mg/1 occurred between the first hours of
operation, Run No. 3'» and the 90th hour of operation, Run No. 33. An
increase from 11,750 mg/l to 21,900 mg/1-occurred between the first
hours of operation, Run No. 37, and the 58th hour of operation, Run
No. 39. No discrete samples of the stabilization tank sludge were
analyzed during a normal run of 4-5 hours. This type of analysis would
have shown how the sludge concentration actually changed with time as a
run progressed.
If the demonstration system is to be used only during periods of high
flow conditions as a result of stormwater runoff or peak dry weather
flow, then the existing method of sludge handling is satisfactory. If
the demonstration system were to be put in series with a storage
facility, and allowed to operate for long periods of time while emptying
the storage facility, additional provisions will have to be made for
wasting sludge. Since the increase in sludge concentration cannot
continue indefinitely, a conventional sludge wasting system will be
needed to control the MLSS concentration. At the present time when the
73
-------
demonstration system goes into operation, the final clarifier is isolated
from the DWP return sludge and waste sludge facilities. Thus, it will
be necessary to allow WAS to be drawn from the demonstration system
final clarifier in a continuous manner and handled by the DWP facilities.
ANCILLARY STUDIES
BOD;COD:TOC Relationship
Beginning in 1973 COD analyses were performed on the raw and final samples
to determine the BODrCOD, BOD:TOC, and COD:TOC relationships. There
were three reasons for this. One reason was to determine the relation-
ship of the BOD:COD ratio in combined sewer overflows. The second reason
was to see if a strong BOD:TOC correlation was evident. The third reason
was to examine the relationship between the COD and TOC.
Data from the raw flow samples for all 26 runs in 1973 was used and data
from the effluent samples for all runs except the 1» solids washout
occurrences was used. The arithmetic means of the ratios from each run
were then calculated. An attempt was also made at fitting the data to
some form of an equation which would be applicable if 3 direct linear
relationship did not exist. Table 11 contains the means, standard
deviations, and equations of best fit.
The BOD:COD ratio of 0.324 for the raw flow is less than might be
expected for normal dry weather municipal wastewater. As is the case
with many combined sewer overflows, the solid particles which can be
oxidized may be complex or difficult to biochemically oxidize in the
5 day BOD period. The equation that has shown to fit the BOD:COD
ratio best in the range of values studies indicates that as the concen-
trations Increase, the COD increase is much greater than the BOD increase,
with the result of a continual lowering of the BOD:COD ratio. The
equation for the BOD:TOC ratio is of the same form as the BOD:COD
equation, indicating a similarity of pattern between the TOC and COD.
The fact that the BODrTOC ratio was not linear and the lack of a good
fit for a curvilinear equation makes predictions of the BOD based upon
TOC measurements unrealiable in this case.
The COD:TOC ratio for the raw flow samples was found to be linear and
to have a good fit. The mean value of 2.66 found for the ratios is very
near that often used in estimating COD concentrations based upon TOC
measurements. It appears that it would be possible to make an estimate
of the COD values in the raw flow based upon TOC measurements, for the
range of values encountered.
The ratios of BOD:COD and BOD:TOC in the effluent samples are reduced
significantly, as would be expected from a biological treatment process.
This indicates higher removal percentages for BOD than TOC and COD, which
is verified by the treatment efficiency data. The resultant equations
-------
Table 11. MEAN AND STANDARD DEVIATIONS FOR
BOD/COD, BOD/TOC, AND COD/TOC RATIOS
Raw
BOD/COD1
BOD/TOC2
COD/TOC3
Fi na 1
BOD/COD
BOD/TOC
COD/TOC
Mean
0.324
0.896
2.660
0.279
0.606
2.200
Standard
deviat ion
0.079
0.252
0.440
0.078
0.184
0.390
Equation of
best fit
BOD - BOD/(2.08 + .0037 x COD)
BOD = TOC/ (0.729 + .004 x TOC)
COD = 42.1 + 2.26(TOC)
BOD = -4.5 + 0.365(COD)
BOD = 0.17 (TOC1'38)
COD = 99-5 - (1056.6/TOC)
Multiple
correlation
coefficient
0.858
0.795
0.933
0.803
0.771
0.750
1. BOD values from Runs No. 35 and 37 and COD value from Run Mo. 48 not used.
2. BOD values from Runs No. 35 and 37 and TOC value from Run No. 42 not used.
3. COD value from Run No. 48 and TOC value from Run No. 42 not used.
-------
show that BOD values increase at a faster rate than the COD or TOC
values as the concentrations in the effluent become higher. However,
the equations have relatively poor correlation coefficients and do not
follow any logical pattern. Generally it appears that the ratio relation-
ships in the effluent are much less predictable than those from the raw
flow data,
During Run No. *»1 , 20 day BOD tests were run on the raw and effluent
samples in addition to the usual 5 day tests. This was done in an
effort to further understand the nature of combined sewer overflow oxygen
demand potential. The results from these analyses are as follows:
5 day, 20 day,
mg/1 mg/1
Raw total BOD 186
Raw dissolved BOD 60 95
Final total BOD 23 99
Fina! dissolved BOD 5 32
The ratios of the 20 day BOD to 5 day BOD for the raw and final are,
respectively, 2,k and 4.3- Since the BOD measurements were only taken
at 5 and 20 days it was not possible to plot the BOD versus time. Thus,
it cannot be readily determined if the high 20 day readings are due to
low deoxygenation rates of the carbonaceous demand or to nitrification.
However, this does bring up the point that perhaps the 5 day BOD
measurement is not a good measurement for determining the oxygen demand
potential of storm generated discharges. In future endeavors, evaluating
the quality or impact of storm generated discharges, it is recommended
that the kinetics of the oxygen demand be determined rather than using
the assumptions commonly associated with municipal wastewaters.
One of the characteristics that was responsible for the satisfactory
treatment performance was the low percentage of BOD and TOC occurring
in the dissolved form. For the 4g raw flows sampled, the arithmetic
mean BOD, TOC, and dissolved BOD and TOC concentrations are listed
below.
BOD concentration, mg/1 H2
Dissolved BOD concentration, mg/1 31
Percent dissolved 27.7
TOC concentration, mg/1 1)6
Dissolved TOC concentration, mg/1 28
Percent dissolved 24, 1
These low percentages of dissolved BOD and TOC make the type of treat-
ment process used by the demonstration system very practical. These
characteristics would probably also lend well to some form of physical-
chemical treatment. Interestingly, the 30 runs at the operating
76
-------
conditions found to be satisfactory achieved an arithmetic mean of 72.1%
dissolved COD and 39-7% dissolved organic carbon removal. The 72. U
removal of dissolved COD is encouraging. However, the 39.7% dissolved
organic carbon removal is unsatisfactory and not fully understood
considering that the total COD and TOC removals were comparable.
Time Series Analyses
During two runs, Nos. 43 and 47, the discrete raw samples were analyzed
separately for TOC and suspended solids concentration to examine the
change in influent quality as a run progressed. The effluent samples
from Run No. 43 were also analyzed separately in an attempt to see if raw
flow characteristics influenced effluent quality. The results from
Run No. 43 are shown in Figure 25. The time scale used for the final
effluent samples has been moved up by 1.5 hours. This is approximately
the process detention time through the system. Also plotted is the flow
rate, corresponding to the effluent time scale. A first flush phenomenon
did appear to be present in this run. No correlation is apparent
between raw concentration and effluent concentration for either suspended
solids or TOC concentrations. However, the suspended solids and TOC
concentrations in the effluent appear to have the same variance with
time. The increase in flow between 8:30 pm and 9:30 pm corresponds with
increases in effluent suspended solids and TOC concentrations. Since
this was the only run during which raw and final samples were analyzed
separately, no further speculation Is warranted.
In addition to the discrete samples from the raw flow during Run No.
47, discrete samples were also taken from the effluent of the DWP
primary sedimentation facilities. This was carried out in an effort
to determine how much removal was occurring as a result of pure settling
and how much as a result of biological action. Figure 26 contains raw
and effluent suspended solids and TOC concentrations plotted versus
time. The detention time through the primary sedimentation tanks was
approximately two hours at the flow rates experienced. The raw and
effluent time scales have been constructed to coincide with the two
hour detention time. The figure does indicate that a significant
amount of the removal occurring in the demonstration system is
accomplished by settling alone. However, it is also evident from the
range of effluent values in the figure that the biological activity
that takes place in the contact process of the demonstration system is
necessary to achieve acceptable effluent quality.
ECONOMIC CONSIDERATIONS
Operating Costs
The integration of the DWP and demonstration system made it Impossible
to monitor the specific costs being incurred by the demonstration system.
For costs such as pumping, chlorination, and sludge disposal, the 1972
costs as developed by the Kenosha WPCP, which included the flows treated
77
-------
450
*™
0)
E
(0
V)
400
350
300
250
40
20
200
9
E
o
o
I-
150
100
50
30
25
20
68,I3O
> (18)
g 6O,56O
x (16!
* 52,990
3~ (14:
Q
3§
u.
RAW
FINAL
5!3O PM
7:00 PM
6)30
8:00
7!3O
9:00
8:30
10 = 00
RAW
FINAL
AND
FLOW
Figure 25. Raw and final sample quality variance with time
78
-------
1390 mg /
500 H
400
- 300 .
0)
E
o
o
i-
200 -
RAW
EFF.
100 -
6:50 AM 7:50
8:5O AM 9:50
8:50
IO:50
TIME
9:50
11 = 50
10150
12-50 PM
11:50
M50
Figure 26. Raw and effluent sample quality
variance through the dry weather plant primary
sedimentation tanks during Run No. ^7
79
-------
by the demonstration system, were used. The biggest cost of the
demonstration system is the power for aeration during dry weather. This
is the power needed for operation of the aerators in the stabilization
tank between runs. Even if the demonstration system was not used during
an entire year, the power costs for the stabilization tank, based on two
aerators running at 30% efficiency and an electrical cost of $0.02/kwh,
would be $14,500.00. During operation of the demonstration system, actual
aeration costs are only 0.199<£/cu m (0.754^/1000 gal.) using four aerators
and including the cost of air to the contact tank. The more the demon-
stration system is used, the lower the aeration costs become in terms of
-------
o
o
o
6.60
(25)
5.28
(20)
o
\
•49-
3.96
(15)
O
O
(D
2.64
(10)
QL
UJ
Q_
O
1.32
(5)
200
400
6OO
800
1000
HOURS OF OPERATION PER YEAR
Figure 27- Estimated demonstration system
operating costs versus hours of operation
-------
C/cu m
32.0
10.6
5-3
3-2
U/1000
121.2
40.4
20.2
12.1
cjal
-------
since this capacity was present before the demonstration system was
installed, only the flow in excess of 87,055 cu m/day (23 mgd) was
considered. The amount of potential overflow treated was then expressed
as a percentage of the total overflow by dividing these values by the
amount of overflow occurring at 67th Street plus the overflow treated.
Although this percentage does not take into consideration the overflow
at the two other discharge sites, 57th and 59th Streets, it does act as
a relative indicator of the effectiveness of the demonstration system
in reducing overflow. As this percentage approaches 100, the volume of
overflow at 67th Street approaches zero, and the volumes at 57th and 59th
Street decrease proportionately.
Using the method of calculation described above, Table 12 has been
constructed indicating the percent of potential combined sewer overflow
treated. During most of the project the system was not put into operation
until an Envirex engineer was present at the WPCP. As a result, overflow
began during most of the events before the demonstration system started
operation. Therefore, Table 12 contains two columns of percentages. The
first column indicates the percentage treated during the entire overflow
event regardless of when the demonstration system went into operation,
and the second column indicates the percentage treated just during the
period while the demonstration system was in operation. The arithmetic
means are 57.5% for the entire overflow event and 69.5% for the period
while the demonstration system operated. Total rainfall for the 28
events ranged from 0.13 cm (0.05 in.) to 5.71* cm (2.26 in.). Figure 28
contains a plot of the percentage treated during system operation versus
total rainfall. Note that these data do not take into consideration
rainfall Intensity or antecedent conditions in the interceptor sewer,
which can greatly affect the volume of overflow.
in
o
ft
100
90 -
80
ro
60
50
40
30
IN 0
CM
.2
.51
A
1.02
.8 1.0 1.2 1.4 1.6 1.8 2.0 2.4 2.6
2.03 2.34 3.O5 3.56 4.06 4.57 5,08 559 6.1
Figure 28. Percentage of overflow treated
versus rainfall amounts for 28 events
83
-------
Table 12. OVERFLOW QUANTITY DATA FROM 1972 AND 1973
00
-t=-
Potential over-
flow treated
Run Rainfall
No.
1
2
3
It
5
6
7
9
10
12
13
14
25
26
27
28
35
36
37
38
39
40
41
42
43
44
45
AM
1.
2.
cm
1.65
2.56
5.75
1.02
0.81
0.68
0.64
1.19
0.66
4.06
0.38
2.67
0.48
0.64
0.38
0.66
0.81
1.65
0.76
0.13
0.51
2.41
2.03
0.38
0.64
0.46
0.30
1.27
i n.
(0.65
(1.01)
(2.26)
(0.40)
(0.32)
(0.27)
(0.25)
(0.47)
(0.26)
(1.60)
(0.15)
(1.05)
(0.19)
(0.25)
(0.15)
(0.26)
(0.32)
(0.65)
(0.30)
(0.05)
(0.20)
(0.95)
(0.80)
(0.15)
(0.25)
(0.18
(0.12)
(0.50)
System ran conti
AM = arithmetic
cu m
5,072
10,749
19,531
6,775
5,678
14,837
8,365
7,267
4,920
19,909
8,289
10,674
3,936
1 1 , 1 28
4,958
5,640
6,737
19,493
77,971
13,702
27,555
5,526
12,490
7,948
12,793
nuously dur
mean.
gal..
x 106
(1.34)
(2.84)
(5.16)
(1.79)
(1.50)
(3.92)
(2.21)
(1.92)
(1.30
(5.26)
(2.19)
(2.82)
(1.04)
(2.94)
(1.31)
(1.49)
(1.78)
(5.15)
(20. 60)1
(3.62)
(7.28)
(1.46)
(3.30)
(2.10)
(3.38)
ing three
Total overflow Overflow treated
at 67th Street during entire
gal
cu m x 1
10,182
23,656
110,295
23,941
7,305
3,974
10,220
15,254
8,365
63,588
13,664
29,674
9,917
11,393
0
0
7,267
20,325
0
0
0
21,499
7,835
681
0
2,839
0
separate
(2.
(6.
(29
(6.
(1.
(1.
(2.
(4.
(2.
(16
(3.
(7.
(2.
(3.
(0.
(0.
(1.
(5.
(0.
(0.
(0.
(5.
(2.
(0.
(0.
(0.
(0.
ra
. , overflow period,
O6
69)
25)
.14)
32)
93)
05)
70)
03)
21)
.8)
61)
84)
62)
01)
00)
00)
92)
37)
00)
00)
00)
68)
07)
18)
00)
75)
00)
! nf a 11s.
percent
33.
31.
15.
22.
43.
78.
45.
32.
37.
23.
37.
26.
28.
49.
100.
100.
48.
48.
100.
100.
100.
38.
77.
89.
100.
73.
100.
57.
2
2
1
1
7
9
0
3
0
8
8
5
4
4
0
0
1
9
0
0
00
9
8
0
0
6
0
5
Overflow treated
during demonstration
system operation ,
percent
79.7
42.5
15.6
23.8
48.6
86.9
94.7
32
53
37
66
39
52
76
100
100
82
52
100
100
100
55
81
97
100
78
100
69
.3
.1
.1
.3
.0
.9
.9
.0
.0
.9
.0
.0
.0
.0
.3
.3
.9
.0
.0
.0
.5
-------
Six of the events in Figure 28, those having total rainfalls of less
than 1.52 cm (0.6 in.) and treatment percentages of less than 60%,
were investigated to determine possible cause for the relatively low
treatment percentages, it was found that for three of these events,
mechanical problems with the raw sewage pumps presented the treatment of
more than 13,550 cu m/day (30 mgd) of flow. The other three events
occurred during periods of extremely high dry weather flow in the
interceptor sewer which decreased the amount of capacity in the inter-
ceptor and the treatment capacity at the plant.
In order to better determine the true effectiveness of the demonstration
system in reducing the overflow, eleven runs were examined in which the
demonstration system was started prior to, or simultaneously with, the
start of overflow. These were Runs No. 9, 27, 28, 36, 37, 38, 39, 42,
44, and the second portion of the rainfall that occurred during Runs No.
14 and 41. The arithmetic mean of the percentage treated for these runs
was 74.6?, with the total amount of rainfall ranging between 0.13 cm
(0.05 in.) and 1.65 cm (0.65 in.). Five of the storms having total
rainfalls of 0.76 cm (0.3 in.) or less resulted in no measured overflow
at 67th Street.
Because of the type of overflow mechanism used in Kenosha, it was suspected
that discharge to Lake Michigan was occurring before the treatment plant
and demonstration system had reached full capacity and before the
interceptor sewer was surcharged. This phenomenon was exemplified by Run
No. 9 occurring on June 2 and 3, '972. Anticipating a rainstorm on the
evening of June 2, the demonstration system was started two hours and
fifty minutes before rainfall began. By the time rainfall began at 1:03
am on June 3, the interceptor level had been lowered to the extent that
the wet well level at the treatment plant was down to 0.27 m (0.9 ft),
almost three feet below normal operating level. The raw sewage pumps which
are paced by this level were discharging less than 56,775 cu m/day
(15 mgd). This meant that the interceptor was very near empty, with the
only flow in the 189,250 cu m/day (50 mgd) interceptor being the 56,775
cu m/day (15 mgd) of dry weather flow common for this time of the morning.
Between 1:03 am and 1:30 am, 0.74 cm (0.29 inches) of rain fell. At
1:25 am, overflow began at 67th Street and within 15 minutes (1:40 am)
the flow level over the dam had reached 83-82 cm (33 in.). However,
during this same 15 minute period of time, the wet well level at the
treatment plant had only risen to 0.91 m (3.0 ft), and the total flow
to the treatment plant was only 113,550 cu m/day (30 mgd), well below
maximum capacity. Not until 2:00 am did the flow to the treatment plant
exceed the plant's capacity and necessitate partial closing of the gate
at the entrance to the wet well. Figure 29 shows the rainfall amount,
overflow level and flow rate through the demonstration system between
1:00 am and 2:00 am. Ideally, overflow would begin only after the
demonstration system and DWP had reached maximum capacity. The shaded
portion above the demonstration system flow rate indicates the unused
-------
Ill
IU
o
u.
ec
UJ
a
(S
5
o
IU
75,700
(20)
56,775
(15)
33,850
(10)
18,98
15)
o
u.
UNUSED
TREATMENT
- CAPACITY
5
1:10 AM
1120
i:30
1:40
i:50
TIME
Figure 29. Rainfall, 67th Street overflow level and
demonstration system flow rate versus time for Run No. 9
86
-------
treatment capacity while overflow was occurring. This indicates a need
for implementation of some type of device, such as inflatable dams and
level sensors, which would guarantee that all flow is diverted to the
interceptor until the treatment plant has reached its capacity and the
interceptor is surcharged.
The overflow data, especially for the events when the demonstration system
was started before overflow began, indicates that under present
conditions up to 0.76 cm (0.3 in.) of rain may fall without a resultant
overflow. However, because of the type of overflow mechanisms in use and
the method of operation during the demonstration project, the following
recommendations are made:
1. Some type of mechanism be installed at the overflow points which
will ensure that the treatment plant has reached capacity and
the interceptor sewer is surcharged before overflow takes place.
2. The demonstration system be put into operation in anticipation
of a storm event, guaranteeing maximum possible capacity in the
interceptor at the onset of a storm.
3. The amount of overflow still occurring under these circumstances
be determined.
k. Based upon the results from No. 3, implement the most economic
storage/treatment capacity still needed to completely eliminate
combined sewer overflow in Kenosha.
87
-------
SECTION VIM -STABILIZATION TANK SLUDGE STUDIES
The sludge condition in the stabilization tank was studied during 1972
and 1973. The data collected in 1972 was analyzed separate from that
collected in 1973. This separation was necessary because the sludge
storage conditions were different during the two periods. In 1972 the
tank was filled with WAS from the DWP and held under static conditions
until the sludge was needed for wet weather flow operation. During the
majority of 1973, WAS from the DWP was continuously pumped through the
stabilization tank in order to maintain the sludge in a dynamic state.
Bench scale tests utilizing WAS were also carried out during 1973 in order
to closely study aspects of aerobic digestion and flotation. The daily
procedures and techniques for performing the sludge studies can be found
in Appendix D.
SLUDGE BEHAVIOR UNDER STATIC CONDITIONS
Static sludge conditions in the stabilization tank ranged between 2 and
27 days in 1972. The period of time under static conditions is referred'
to as the sludge age. Three periods were of sufficient duration so as to
be studied for changes in sludge characteristics.
The first period was from June 19 to June 26, 1972, a period of seven
days. During this period the only parameter monitored regularly was the
oxygen uptake rate (OUR). No settling tests were being run and SS and VSS
concentrations were checked only twice. The change in the OUR during the
period showed a rapid decrease in the OUR between a sludge age of 2 and
k days and then an increase between 4 and 7 days. The decrease indicated
a very rapid stabilization of the sludge. The increase may have been
caused by an increase in sludge temperature which caused an increase in
the bioactivity. Data from longer periods showed that over an extended
period, the initial drop in OUR is drastic but thenlevels out after about
5~7 days and further decreases in OUR are slight. During this time an
increase in temperature may override the expected OUR decrease due to
endogenous respiration and give a net result of an increase in the OUR.
The two samples taken for SS and VSS concentration analysis were taken
during Run No. 12 on June 19, 1972 and on June 26, 1972. The composite
during the run yielded a sludge concentration of 13,575 mg/1 SS and 8,110
mg/1 VSS. After the seven days the SS concentration was 6,725 mg/1 and
the VSS concentration was 2,275 mg/1. The reduction in volatile solids
percentage, 59-7 to 33.8, indicates that extensive endogenous respiration
88
-------
took place while the sludge was in the static state. The 33.8% volatile
solids on June 26 raised doubt as to the usefulness of the sludge for
the demonstration system after holding it for seven days. These test
results led to the decision to empty the stabilization tank and refill it
with a fresh supply of WAS.
The second period of study occurred from July 19 to July 31, 1972, a
period of 12 days. During this period, the OUR was monitored daily and
the SS and VSS concentrations were checked twice. SS and VSS concentra"
tions were taken only at a sludge age of 1 day and a sludge age of 9 days.
The OUR's showed a marked decrease in the bioactivity of the sludge. The
decrease reached a maximum at 7 days after which the uptake rate remained
fairly constant. An increase in OUR from 8 mg/l/hr at a sludge age of
7 days to 12 mg/l/hr at a sludge age of 8 days showed a direct correlation
with the temperature change of 18.5 C to 22.0 C that occurred during that
period. This observation reinforced the assumption that the OUR decreased
to a minimum in a period of about 5~7 days after which the sludge temper-
ature is mainly responsible for the OUR fluctuations.
The two samples analyzed for SS and VSS concentrations during this period
showed the extent of the endogenous respiration taking place in the
stabilization tanks. On July 20 the SS concentration was 14,633 mg/1
and the VSS concentration was 8,333 mg/1. This resulted in a percent
volatile solids of 56.9. After 9 days under static conditions the values
were 6,675 mg/1 SS, 3,200 mg/1 VSS, and percent volatile, ^7-9. Taking
these results in conjunction with the OUR results, it can be concluded
that the viability of the sludge for use in the demonstration system
would be insufficient. The period of static detention ended with the
occurrence of Run No. 18 on August 2, 1972. The results of the
demonstration system using the deteriorated sludge were relatively poor
as anticipated: percent BOD removal, 61.2; percent SS removal, 82.7;
and percent TOC removal, 64.5-
The third period of study was from August 15 to September 11, 1972, a
period of 27 days. The OUR and temperature are shown in Figure 30, the
SS concentration, the VSS concentration, and percent volatile suspended
solids in Figure 31, and the settling rates, which were measured beginning
on August 18, in Figure 32. The OUR once again dropped drastically
during the first 7 days of stabilization and then only fluctuated as a
function of the temperature. The SS concentration dropped steadily from
a value of 16,375 mg/1 to 12,825 mg/1 after 19 days. This was a reduction
of 21.7%. The VSS concentration dropped from 8,775 mg/1 to 7,250 mg/1 over
the period of 9 days that VSS concentrations were monitored. The volatile
solids percentage dropped from 53-6 to 51.5. These results showed a
17.5% decrease in the VSS concentration and a 3-9% decrease in the percent
volatile solids. Since the first sample was taken at a sludge age of
8 days, the percentages from day zero are higher than those calculated.
These observations again reinforce the fact that extensive digestion of
the sludge occurs in the stabilization tank and thus the viability of
the sludge for use in the demonstration system rapidly decreases.
-------
r
i
14* • K> 12 14 » II 20 22 24 i«
SLUDGE ME (DAYS)
Figure 30. Oxygen Uptake Rate and
Sludge Temperature versus Sludge Age for
August 18, 1972 to September 1972
M.OOO
12.000
»*
r
•«
5
8
1,000
C.OOO
f • 10 12 14 !• IB 20 22 24 20 2a
•LUOW AGE (DAYS)
Figure 31. SS, VSS, and Percent
Volatile Solids versus Sludge Age for
August 18, 1972 to September II, 1972
5 (1200) 41.e
SUH>GE AGE - DATS
Figure 32. Calculated Surface Overflow Rate
versus Sludge Age for
August 18, 1972 to September II, 1972
90
-------
As stated previously, settling tests were run beginning on August 18,
1972. The graph of the settling rates revealed an interesting point:
the settling rate increased as the digestion time increased, however,
by observation the supernatant became increasingly more turbid until
the point was reached where the settling rate could not be calculated
because the interface could not be seen during the settling test. This
phenomenon led to the following:
1. The possibility that increased digestion led to fast settling
by inert solids which did not produce a clear supernatant.
2. The decision to observe the relationship between settling rate,
SVI, and supernatant SS concentration during the sludge studies
in 1973.
The following conclusions were drawn from the 1972 sludge studies:
1. After 5 to 7 days it appears the aerobic digestion of the sludge
is almost completely achieved.
2. After 5 to 7 days the usefulness of the sludge mass for the
demonstration system is doubtful.
3. Sludge appears to settle faster as aerobic digestion proceeds.
This may be due to increasing amounts of inert material
(i.e., a decrease in percent volatile solids).
CONTINUOUS FLOW THROUGH THE STABILIZATION TANK
Operation of the demonstration system employing continuous flow through
the stabilization tank during dry weather began in May of 1973 and
continued throughout most of the remaining year. WAS was continuously
pumped from the DWP to the stabilization tank. In the tank it was
aerated for a period of time, the hydraulic detention time averaged 2.5
days, and then pumped to the DWP sludge thickening flotation unit.
Daily monitoring of the stabilization tank sludge began on May 13, 1973.
As in 1972, the sludge temperature, volume in the tank, and OUR were
monitored. New parameters were also added in order to better understand
what was happening to the sludge. These measurements were mean air
temperature, flow rate into and out of the stabilization tank, suspended
and volatile suspended solids concentration, plant influent suspended
solids concentration (this value was used to calculate a SVI value),
mixed liquor settling rate using 750 ml of DWP influent and 250 ml of
stabilization tank sludge, suspended solids concentration in the settling
test supernatant, and the sludge volume after 30 minutes of mixed liquor
settling. From the data obtained the following parameters were calculated:
OUR (mg/hr/gm VSS), the hydraulic detention time, the settling rate, and
the SVI. Four periods of sufficient duration for study of continuous
91
-------
flow conditions occurred during 1973- Other periods were too short in
duration as a result of demonstration system runs occurring close
together. In the selection of time periods when continuous flow
conditions existed, it was assumed that continuous flow began one sludge
age (tank turnover) after the end of static conditions.
The first period studied was from May 16 to May 25, 1973. The OUR
(mg/hr/gm) steadily increased during this period. It was expected that
this value would remain relatively constant under continuous flow
conditions. However, a plot of sludge temperature versus time showed
that the unexpected increases in the OUR correlated well with the increases
in the sludge temperature. Thus during continuous flow situations the
sludge temperature may be an important parameter affecting the
viability of the sludge. The effect of the sludge temperature on the
treatment potential of the sludge in demonstration process operation is
hard to establish because most runs were during the summer months when
the sludge temperature was 20 C or above. This point should be considered,
however, if the system is used for early spring snowmelts or rains, or
late fall rains. As with conventional activated sludge plants, this
problem can be handled by increasing the recommended mixed liquor SS
concentrations. The settling rate increased, the settling test super-
natant SS concentrations decreased, and the SVI's decreased during this
period. These results also add to the conclusion that the treatment
potential of the sludge was increasing as the sludge temperature was
increasing with the beginning of summer conditions. The SS concentration,
VSS concentration, percent volatile solids, and the SS concentration of
the WAS coming into the stabilization tank were very erratic. These
results reveal two facts about the system that should be considered
because they constantly appeared throughout the study:
I. The viability of the stabilization tank sludge and thus the
potential performance of the demonstration system is almost
entirely dependent on the condition of the sludge obtained
from the DWP.
2. The WAS characteristics are damped by the stabilization tank
because of the similarity to a complete mix situation which
exists in the stabilization tank. Therefore, significant
changes in the characteristics of the sludge coming into the
stabilization tank can be diluted so that the change in
stabilization tank sludge is more gradual.
The treatment efficiency by the demonstration system after this dry
period indicated very good treatment, therefore the continuous flow
system was successful in maintaining a viable solids mass. As shown
during 1972, a period of 11 days under static conditions would have
resulted in very poor system performance. This underscores the point
that the continuous flow system is a major part of the demonstration
system and every effort should be made to keep it operable.
-------
The next period of study was from June 28 to July 3, 1973. Data from
this period showed decreasing concentrations of SS, VSS, percent volatile
solids in the stabilization tank, and a slightly decreasing SS concen-
tration in the WAS coming into the stabilization tank. The settling
rate was lower, and the SVt and supernatant SS concentrations higher
than those obtained during the first period of testing. Once again the
OUR seemed to follow the temperature of the sludge. These results
indicated that the sludge monitored during this time was not as
advantageous to the demonstration system as the sludge during the first
period of study. This deteriorated sludge was used during Run No. kQ on
July 3 and did not settle well, resulting in solids being carried out in
the effluent.
During this run the three DWP clarifiers also experienced extensive
solids washout. This problem of poor setlting sludge continued to plague
the demonstration system for the next month and a half and exemplified the
dependency of the system on the condition of the sludge supplied by the
DWP.
The next period of study for continuous flow was July 9 to July 20, 1973-
The data obtained during this period is presented in Table 13 and plotted
in Figures 33 to 37- The OUR (Figure 3M showed a drop from 9-30 to 5.80
mg/hr/gm during the first four days of continuous flow conditions, and
then a leveling off at a constant value of about 6.0 mg/hr/gm. The
consistent values that were recorded after 4 days is what would be expected
in a continuous flow situation. The settling test supernatant SS
concentration (Figure 35) showed good results after 2 days, the settling
rate (Figure 36) showed improvement after 2 days, but the SVI values for
this period were all over 100 ml/gm with an average value of 122 ml/gm.
The initial rapid changes in the first two days of continuous flow could
have been due to the fact the equilibrium conditions were not established
immediately. This would also be true for the changes for the OUR. The
values obtained after two days indicated 1) the sludge was settling faster,
2) good treatment could be expected, 3) but the volume of the settled
sludge was large.
Figure 33 shows 1) the stabilization tank by its mixing action was damping
the fluctuations in the WAS SS concentration coming into the tank, 2)
the overall pattern of solids decrease in the WAS coming into the tank
was reflected in the stabilization tank sludge SS and VSS concentrations,
and 3) the percent volatile suspended solids remained fairly constant
throughout the period. The study period ended with Run No. Al, which
achieved satisfactory removal efficiencies. However, the efficiency was
based upon a composite sample from the first four hours of system
operation. After about 4 1/2 hours, solids began washing out of all four
clarifiers. The explanation of what happened during Run No. ^l refers
back to the monitoring of supernatant SS concentration, SVI, and settling
rate. The sludge achieved good treatment and settled well but the
settled volume was large, therefore, it took up an excessive volume in
the clarifier. This volume increased to the point where solids were
-------
Table 13. MEASURED PARAMETERS FOR STABILIZATION TANK SLUDGE
JULY 9 TO JULY 20, 1973
V..Q
-c-
SS, VSS, Percent OUR
Date mg/1 mg/1 volatile (mg/hr/gm)
7/9 8,230 4,410 53.6 9.30
7/10
7/11 3,730 A, 550 51-8 7.91
7/12
7/13 9,000 it, 790 53,2 5.85
7/1'*
7/15
7/16 8,220 4,370 53-2 5-72
7/17
7/13 7,470 3,970 53-1 5-79
7/19
7/2C 7,170 3,780 52.7 6.48
AMa S, 145
Settl f nq rate
cu m/day/sq m
(gpd/sq ft)
^0.7 (997)
30.5 (748)
33-2 (814)
40.9 (1002)
46.4 (1133)
Settl ing test DWP RAS SS
SVI supernatant concentration,
ml/gm SS cone., mg/1 mg/1
102.7 106 7,600
7,300
128.3 54 7,200
7,200
121.1 68 8,200
6,700
7,400
6,500
7,100
121.8 6,400
6,900
116.4 66 6,300
7,067
a. AM = arithmetic mean.
-------
9,000
8,000
7.OOO
"X
-------
DAYS IN CONTINUOUS FLOW
Figure 31*. Oxygen Uptake Rate
versus Days of Continuous Flow
for July 9, '973 to July 20, 1973
DAYS IN CONTINUOUS FLOW
Figure 35. Supernatant SS Concentration
versus Days of Continuous Flow for
July 9, 1973 to July 20, 1973
CU M/ OAY /SO.M
(GPO/FT.2)
400
(1000)
DAYS IN CONTINUOUS FLOW
Figure 36. Calculated Surface Overflow Rate
versus Days of Continuous Flow
for'July 9, 1973 to July 20, 1973
DAYS IN CONTINUOUS FLOW
Figure 37. Calculated Sludge Volume Index
versus Days of Continuous Flow for
July 9, 1973 to July 20, 1973
96
-------
picked up and carried out in the effluent. This seems to be what happened
to both the DWP clarifiers and the demonstration system clarifier. This
problem plagued the demonstration system for part of the year because of
the condition of the sludge obtained from the DWP.
The last period available for study was August 13 to August 23, 1973. On
August 20, or day 7 of continuous flow conditions, the addition of a non-
ionic polymer to the DWP mixed liquor was begun in an attempt to improve
settling characteristics of the sludge. The SVI remained constant through-
out the period as would be expected in a well operating continuous flow
system. No change was shown after the seventh day when polymer was added.
However, the OUR was approximately 7-50 mg/hr/gm for the first three samples
before polymer addition, but after the addition began it dropped to 4.10
mg/hr/gm. The settling test supernatant SS concentration held constant
at 117 nig/1 for the first three samples, but after polymer addition it
increased to 220 mg/1. The three calculated settling rates before addition
were 68.1 (1,670), 56.7 (1,390) and 58.3 cu m/day/sq m (1,430 gpd/sq ft)
while the day after polymer addition began the settling rate was 52.2
(1,280) and after three days of polymer addition it was 45-9 cu m/day/sq m
(1,125 gpd/sq ft).
This data led to speculation that the addition of the polymer may have
maintained the SVI. The addition was followed by a reduction of the
bioactivity of the sludge as measured by the OUR and the settling super-
natant SS concentration. Because of these results the effectiveness of
employing the polymer as a solution to the problem of poor sludge should
be studied carefully before it is continued. This is another case of the
demonstration process being dependent on what was happening to the DWP
sludge.
The conclusions after the study of continuous flow conditions in the
demonstration system are:
1. The demonstration system is dependent on the condition of the
sludge obtained from the DWP. Therefore, the effect on the
demonstration system must be considered when changes are made
concerning the DWP sludge.
2. The stabilization tank is able to reduce shock changes in the
characteristics of the WAS due to its mixing conditions.
However, long term changes will be reflected in the quality of
the stabilization tank sludge.
3. The average OUR for the study was 6.0 mg/hr/gm.
If the continuous flow system is kept in a good operating
condition, satisfactory treatment is possible after long periods
of dry weather. It has been shown that static conditions cause
a drastic decrease in demonstration process efficiency after
5-7 days of dry weather.
97
-------
5. The values obtained during the study program can be used to
determine the air requirements of the system during dry weather.
Upper VSS concentration 95% confidence limit » 7-824 mg/1
Upper OUR 95% confidence limit - 9-3 mg/hr/gm
Oxygen supplied by two 50 hp mechanical aerators:
2.5 Ib/hp-hr x 2 aerators x 60 hp/aerator =
250 Ib/hr = 113.5 hr/hr
Oxygen required by the sludge:
9.3 mg/hr/gm x 7-824 gm/1 - 72.8 mg/l/hr
Maximum allowable volume of sludge for two aerators:
72.8 mg/l/hr x V (million gal.) x 8.34 - 250 Ib/hr
v - 1,558 cu m (411,700 gal.)
Therefore, if only two aerators, are used, the allowable volume of
sludge in the stabilization tank is 1,558 cu m (411,700 gal.).
For volumes over 1,558 cu m (411,700 gal.), three aerators
should be used.
BENCH SCALE STUDIES
In addition to monitoring the sludge in the stabilization tank, sludge
studies were also conducted on a bench scale at the DWP. The purpose of
these studies was twofold:
1. To obtain a better understanding of the sludge digestion that
occurs in the stabilization tank during dry weather.
2. To study the effect of this digestion on thickening the sludge
with dissolved air flotation. This aspect is of concern because
after a hydraulic detention time of two to three days in the
stabilization tank, the WAS is pumped to the DWP dissolved air
flotation unit for thickening.
Three test periods were used for the digestion and flotation studies and
the results are shown in Tables 14 to 16. The SS, VSS, total COD, and
total alkalinity concentrations of the sludge for the three test periods
are plotted in Figures 38 to 40. The three figures strongly indicate
extensive aerobic digestion. The SS and VSS concentrations yield an
average destruction rate of 215 mg/l/day SS and 157 mg/l/day VSS. Since
the SS destruction is due mainly to the destruction of volatiles by
aerobic digestion, the percent volatile fraction of the total suspended
solids also drops. Therefore, in the demonstration system stabilization
tank a similar rate of decrease could be expected. Of course, these
rates will vary with changes in temperature.
38
-------
Table 14. AEROBIC DIGESTION AND FLOTATION RESULTS
JULY 11 TO JULY 31, 1973
V.Q
UD
Date
7/11
7/12
7/13
7/15
7/17
7/18
7/20
7/23
7/26
7/31
SS
mg/1
7,076
6,727
6,312
6,030
5,506
5,340
4,800
4,680
3,855
VSS
mg/1
3,475
3,220
2,756
2,660
2,320
2,190
1,870
Percent
volati le
55.1
53-4
50.1
49.8
48.3
46.8
48.5
OUR
(mg/hr/gm)
5
2
2
2
2
1
1
.99
.52
.10
.18
-50
.92
.60
Total Total Percent
alkalinity, COO float
mg/1 mg/1 sol ids
523 2
2
30 2
16 4,630
2
2
3,766 2
1
8 2,888 2
.16
.28
.34
.38
.25
.20
.87
.13
Effluent
SS,
mo/1
28
80
112
88
65
95
115
no
Percent Rise Rate
sol ids cm/sec
recovery (fpm)
99.0
96.8
95-3
96.9
94.8
93.5
92.4
0.18
0.17
0.07
0.16
0.14
0.12
0.12
0.12
(0.36)
(0.34)
(0.13)
(0.31)
(0.27)
(0.33)
(0.23)
(0.23)
-------
Table 15- AEROBIC DIGESTION AND FLOTATION RESULTS
AUGUST 8 TO AUGUST 23, 1973
o
o
Date
8/8
8/9
8/13
8/15
8/16
8/17
8/21
8/23
SS,
mg/1
10,600
10,100
8,788
7,240
7,070
6,460
6,300
vss,
mg/1
7,012
6,712
5,588
4,440
4,370
3,940
37,20
Percent
volat i le
66.2
66.4
63-6
61.3
61 .8
61 .0
59-0
OUR
(mg/hr/gm)
28
6
3
2
2
1
1
.67
.56
.58
.52
.75
.65
.13
Total Total Percent
alkalinity, COD, float
mg/1 rng/1 sol i ds
260 2
2
29 2
8,048
2
2
0 5,910 2
33 5,755 2
.25
.76
-71
.40
.57
.38
.68
Effluent
SS,
mg/1
13
45
190
85
65
152
150
Percent
sol ids ,
recovery
98
94
96
97
93
93
.9
.5
.9
.6
.8
.8
Rise Rate
cm/sec
(fpm)
0.07 (0.14)
0.20 (0.39)
0.19 (0.37)
0.18 (0.36)
0.21 (0.41)
0.16 (0.32)
-------
Table 16. AEROBIC DIGESTION AND FLOTATION RESULTS
AUGUST 28 TO SEPTEMBER 19, 1973
Date
8/28
8/29
8/31
9/4
9/6
9/7
9/10
9/12
9/14
9/17
9/19
SS,
mg/1
9,690
8,860
8,490
7,310
6,380
6,040
5,980
5,260
vss,
mg/1
6,450
5,480
5,320
4,560
3,750
3,570
3,940
3,290
Percent
Vo 1 a t i 1 e
66.
61.
62.
62.
58.
59-
65.
62,
6
8
7
4
8
1
9
5
OUR
(mg/hr/gm)
39.07
7.70
5.17
2.85
1.65
0.90
0.89
1 .06
Total Total Percent
alkalinity COD float
mg/1 mg/1 sol ids
216 9,176 2.941
8,632 2.70
35 2.75
6,652 2.49
6
6,008 2.70
5
2.70
0 5,910 2.58
o 4,787
2.43
Effluent
SS,
mg/1
140
60
105
138
145
225
215
270
Percent Rise Rate,
sol ids cm/sec
recovery (fpm)
96.
98.
96.
95.
94.
89.
90.
86.
31
3
8
I
0
9
3
2
0.21 (0.
0.37(0.
0.37(0.
0.55(1.
0.37(0.
0.47(0.
0.30(0.
41)'
72)
72)
09)
72)
93)
60)
-------
7,000
6,000 -
5,000 \
4,OOO -
o>
E
co
in
CO
CO
3,000 -
2.000
1,000 -
10
15
20
SLUDGE AGE (DAYS)
Figure 38. SS, VSS, Total COD, and Total Alkalinity
Concentration versus Sludge Age for Bench Scale Tests
July 11, 1973 to July 31, 1973
'02
-------
10,000 r
9,000 -
3,000
l I I I I I I
8,000 -
5OO
tr>
Q
O
O
400
6,OOO -
300
<
f
5,000
20O
100
5 10
SLUDGE AGE (DAYS)
15
Figure 39. SS, VSS, Total COD, and Total Alkalinity
Concentrations versus Sludge Age for Bench Scale Tests,
August 8, 1973 to August 23, 1973
103
-------
3,000
10
15
20
SLUDGE AGE
Figure AO. SS, VSS, Total COD, and
Concentrations versus Sludge Age for
August 28, 1973 to September
(DAYS)
Total Alkalini ty
Bench Scale Tests
19, 1973
104
-------
An attempt was made at determining a rate constant for the system using
the equation:
ln[S -S )/(S -S )] = K.t, where
r n t n 1
S = VSS concentration at time t
n
S = nonoxidizable VSS concentration
S = initial VSS concentration
t = time of aeration in days
K. = rate of digestion (a constant)
This formula is derived from the endogenous respiration equation
Ma* = Mao (e ) where Mat = the active biological mass at time t,
and Mao = the initial active biological mass.
In the former equation the rate K. is dependent, to some extent, upon the
value chosen for Sn, the nonoxidizable VSS concentration. For this
formulation Sn is considered to be five percent less than the difference
between the initial VSS concentration and the final VSS concentration.
This estimate of the nonoxidizable VSS concentration has been suggested
by Barnhart (30). This formula was applied to the results of the three
studies. In the case of the first study (July 11 to July 31) the result
of (S -S ) was a negative number and, therefore, the rate constant was
not calculated. Studies 2 and 3 (August 8 to August 23 and August 23 to
September 9) resulted in rate constants of -0.125/day and -0.13Vday,
respectively. For domestic sludges the usual value is about -0.25 to
-0.40/day.
The total alkalinity pattern was interesting. The alkalinity of the
sludge dropped very rapidly in the first 5 days and at 7 days no
detectable alkalinity remained. For zero total ajkalinity the pH of the
sludge would be expected to be around 4.5- This occurrence indicates that
extensive nitrification may be taking place in the stabilization tank.
During nitrification ammonia nitrogen is converted to nitrates by
nitrifying bacteria.
The following equations (not balanced) show why the pH drops in the
nitrification process:
Organic N + H20 •* NH3 + OH~ 0)
(2)
(3)
CO
HCO + OH >
NH3 + 02 ->
+
C0_ + H
N03 + H
H2C03
05
-------
Equation 1 indicates the change of the organic nitrogen to ammonia.
This reaction produces OH" ions, which in turn react with HCO-j to
produce COo (eq. 2). These reactions then cause a shift In the total
alkalinity form from HCO^ to 003 and this will first cause the pH to
rise. Without nitrification, the pH would continue to rise as organic
nitrogen is converted into ammonia.
Equations 3, 4, and 5 indicate the reactions occurring because of ongoing
nitrification. NH^ reacts with 02 to produce NO-j and an H+ ion. This
is accomplished by the nitrifying bacteria. The H+ ion produced then
reacts with HCO, to produce H2C03 which further reacts to produce h^O
and CO- which escape from the system. Therefore, nitrification destroys
alkalinity and the pH will drop. The lower pH will inhibit the
biological activity of the system and thus lower the digestion rate
constant to a value less than that expected,
The OUR's for the three studies are plotted in Figures 41-43. The plots
show a very high initial uptake rate which drops rapidly during the first
5 to 7 days of digestion. They also show that the uptake rate has reached
a steady rate after about 7 days of digestion in the first and third
studies. The uptake rate data was also analyzed in order to develop an
equation for predicting the uptake rate at different sludge ages. The
following equation, having a multiple correlation coefficient of 0.946
was developed:
OUR (mg/hr/gm)= 8.09 (SA)~° (1.024T~T°)
where: T = sludge temperature, C
T = 20°C
o
SA = sludge age >_ 1 day
1.024 = temp, coefficient
From the data presented, it appears that when this value reaches the
range of 1 to 2 mg/hr/gm, the sludge has been completely stabilized and
its usefulness in the demonstration system is doubtful.
The percent solids in the float and the effluent SS concentrations are
plotted in Figures 44-46. Figure 46 shows a change in the two patterns.
This was due to a change in the sludge condition in the DWP. The
sludge obtained for the last study contained the polymer which was not
present during the first two studies, and a noticeable change occurred
in the results of the flotation tests. The first two studies indicate
increasing percent solids in the float for up to five days of digestion,
and then decreasing values. The third study, with the polymer present,
shows a steady drop in percent solids. The effluent SS concentrations
were erratic, but the first two tests show a general increase in
suspended solids with time, and the third test shows a similar pattern
after a drop which occurred on the first day of digestion. Referring
to Tables 14-16, the SS recovery percentages also follow the pattern with
gradually decreasing values as stabilization continues. The rise rate
!06
-------
o
—J
SLUDGE AGE (DAYS)
Figure ^1. Oxygen Uptake Kate
versus Sludge Age for Bench Scale Tests,
July I I, 1973 to July 31, 1973
SLUDGE AGE (DAYS)
Figure ^2. Oxygen Uptake Rate
versus Sludge Age for Bench Scale Tests,
August 8, 1973 to August 23, 1973
SLUOGE A&E (DAYS)
figure ^3. Oxygen Uptake Rate
versus Sludge Age for Bench Scale Tests
August 28 to September 19, 1973
-------
o
CO
KX> r- I r-
SLUOGE AGE (OATS)
Figure M. Flotation Test Percent
Float Solids and Effluent SS versus
Sludge Age for July 11, 1973 to July 31, 1973
SLUDGE AGE [DAYS >
Figure <*$. Effluent SS and Percent
Float Solids Versus Sludge Age for Bench Scale Tests
August 8, 1973 to August 23, 1973
* POLYMER A001TIOM
SLUDGE AGE (DAYS)
Figure 46. Flotation Test Percent
Float Solids and Effluent SS versus Sludge Age
for August 28, 1973 to September 19, 1973
-------
values (Tables 14-16) are very erratic mainly because of the time
necessary before the interface develops and the speed at which it rises,
making exact timing very difficult. From observation of the data,
however, the following general statements can be made: 1) aeration of
the sludge for up to 10 days does not reduce the rise rate, in fact,
it may improve it, and 2) after 10 days the rise rate gradually decreases,
but not below the value obtained for the fresh sludge before stabiliza-
tion began (t = 0).
The conclusions from this study are:
1. A SS destruction rate of 215 mg/l/day and volatile suspended solids
destruction rate of 157 mg/l/day can be expected in the stabili-
zation tank, based upon the bench scale tests. Therefore, the
solids loading on the air flotation unit will be decreased by
means of aerobic digestion. These rates are averages over the
twenty days of digestion; however, graphs show that they are
fai rly constant.
2. An average rate constant (K) of-0.13/day was obtained for the
aerobic digestion of the sludge.
3. The OUR (mg/hr/gm) was found to be related to the time of
digestion by the relationship:
OUR (mg/hr/gm) = 8.09 (sludge age)"°'62 (1.024T~T°)
4. Extensive nitrification was suspected in the stabilization tank.
This would reduce the pH. The pH of 4.5 (indicated by total
alkalinity = 0) may be the reason that the sludge did not
perform well in the demonstration system after 5 to 7 days of
stabi1i zation.
5. No detrimental effect on the percent solids in flotation was
found. In fact, it appeared that the float solids concentration
was improved by up to five days of sludge aeration.
6. The flotation effluent SS concentration increased as the sludge
was digested; this correlates well with the settling tests where
it was found that as digestion proceeded, settling was improved
but the effluent became increasingly more turbid.
7. The rise rate of the sludge in flotation was not decreased by
digestion. Like the float solids, it seemed to increase over
the first five days of stabilization.
109
-------
SECTION IX - FUTURE DESIGN CONSIDERATIONS
AERATION
As discussed previously, eight 50 hp floating mechanical aerators were
provided and utilized in the stabilization tank. The main reasons for
using the surface aerators were to avoid the necessity of having to
construct additional blower facilities and the ability of these aerators
to easily adapt to changes in the sludge level. These aerators provided
sufficient oxygen and mixing and operated reliably with little maintenance
during the duration of the project. However, after completion of the
evaluation program, operating experience indicated that fixed air disperser
systems may be better suited for use in the stabilization tank. This type
of disperser system would allow for winter operation. Also, in future
designs it will not be necessary to make provisions for varying depth of
sludge, since a design volume (depth) #i11 be chosen and used at all times.
Although winter operation was never attempted, it was anticipated that
the WAS being aerated would freeze on the aerators themselves and on the
support wires and possibly cause the aerators to sink. This problem is
not prevalent in normal aeration applications where the hydraulic
detention time is much shorter and the liquid is not afforded as long of
a period of time to cool down to ambient temperatures. The submerged air
dtffuser system will most likely allow surface icing to occur. However,
it will still be possible to use the system during winter rainfalls and
snow melts since the volume of sludge under the ice layer would be usable.
In climates where cold weather and possible freezing is not of main
concern, the choice of aeration system type should be done by the same
means as for any other application.
INSTRUMENTATION AND FACILITIES
In future uses of this type of system all of the sophisticated automatic
controls used in the demonstration system will not be needed. These
automatic controls were required by the test program which called for a
high degree of control on the process variables. It will be sufficient
to provide direct manual controls for selecting the sludge transfer and
sludge return rates, the air supply rate, and the sludge wasting rate.
It appears that no provision for borrowing sludge from the DWP Is needed.
In addition, the controls for automatic start-up at high flows may not be
needed if this system is to be put into operation in anticipation of high
flow periods.
-------
Future systems of this type will not require the high capacity sludge
return and sludge transfer pumping facilities used in the demonstration
system. For purposes of the test program these pumps had a capacity
equal to 100% of the maximum raw flow rate. These capacities can be
determined for future installations through a knowledge of the desired
MLSS concentration and the estimated settled sludge concentration In the
final clarifier.
It will not be necessary to divide the contact tank into two compartments.
The design of the contact tank can be based on the maximum design flow
rate. At flows less than this the additional contact time provided will
be beneficial. If the system is designed to have a high range of flows it
may be necessary to use a partitioned stabilization tank. If the stabili-
zation tank is designed to provide the proper amount of reaeration time
at maximum flow it is possible that this would produce too long of a
reaeration time at lower flows when the sludge transfer and sludge return
rates are greatly reduced, thus, the need for the partitioned tank.
Grit removal facilities should definitely be constructed with some type
of mechanical removal equipment. Although no specific measurements were
carried out to determine the amount of grit deposited during a run, it
was estimated by WPCP personnel that 0.75-1-5 cu m (1-2 cu yds) were
deposited per 3785 cu m (million gal.) treated. Manual removal of this
grit was both a lengthy and bothersome process for the WPCP operators.
SIZING WITH RESPECT TO EXISTING TREATMENT PLANT
The maximum size of this type of system relative to the existing
activated sludge plant that it is integrated with is determined by two
constraints. These are:
1. The volume of sludge being held in the stabilization tank,
between storms, under continuous flow through conditions,
should not provide a hydraulic detention time of more than 5
days.
2. When the demonstration system goes into operation the volume
of sludge in the stabilization tank must be sufficient to
provide at least one hour of reaeration. Using the Kenosha
WPCP as an example, the maximum volume of sludge that can be
held in the stabilization tank with a hydraulic detention of
less than 5 days is 1892 cu m (500,000 gal.). This is based on
an average DWP WAS rate of 379 cu m/day (100,000 gpd). During
operation of the demonstration system the maximum rate of RAS
into and out of the stabilization tank at a reaeration time of
one hour would be 45,^20 cu m/day (12 mgd). Assuming that a
sludge transfer (RAS) percentage of 33% is required to achieve
the desired MLSS concentration, then the maximum design flow
-------
rate would be 136,260 cu m/day (36 mgd). An important factor in deter-
mining how large the potential overflow treatment system can be, is the
percent sludge transfer required. This, of course, is a function of the
desired MLSS concentration, and the expected RAS concentration from the
final clarifier. Using Kenosha, as an example again, if an MLSS
concentration of 2500 mg/1 was desired, and the RAS concentration was
15,000 mg/1, the sludge transfer rate would only be 20% of the raw flow
rate. This would enable the potential overflow treatment system to be
five times the RAS rate, or 227,100 cu m/day (60 mgd). Thus, it is
important for any future design of this type of system to be prefaced by
bench scale tests for determination of design MLSS concentration, and
expected RAS sludge concentration.
12
-------
SECTION X - REFERENCES
1. "Engineering Report on Relief, Extension, and Conversion of Sewer
Facilities for the City of Kenosha, Wisconsin", Consoer, Townsend
and Associates Consulting Engineers, Chicago, Illinois (1966).
2. Division of Resource Development Order No. 4B-68-3-3, State
of Wisconsin Department of Natural Resources, June 5, 1968.
3. Parkland, E., "First Reports, Rivers Pollution Commission",
England, 1868.
k. Dunbar, "Principles of Sewage Treatment", London, 1907-
5. Arden, E., "Sewage Purification with Reference to Colloid Chemistry",
British Assoc. Adv. Science, 2nd Report on Colloid Chemistry,
pg. 81-85, 1921.
6. Theriault, E. J., and McNamee, P. S., "Sludge Aeration Experiments.
I. Rate of Disappearance of Oxygen in Sludge". Ind. Eng. Chem., 22
1330-1336, 1930.
7. Theriault, E. J., "Studies of Sewage Treatment. III. The
Clarification of Sewage. A Review". Sewage Works Journal,
7/12/928, 1935.
8. Editorial, "Activated Sludge Research", Sewage Works Journal,
7/12/928, 1935.
9. Heukelekian, H., "Studies on the Clarification Stage of the
Activated Sludge Process", Sewage Works Journal, 8/11/873, 1936.
10. Heukelekian, H., "Studies on the Clarification Stage of the
Activated Sludge Process, II. Factors Influencing the Clarification
of Sewage by Activated Sludge", Sewage Works Journal, 9/5/A31, 1937-
11. Heukelekian, H., ajnd Ingots, R. S., "Studies on the Clarification of
Activated Sludge. III. Carbon Dioxide Production During the
Clarification and Oxidation States of Activated Sludge", Sewage
Works Journal, 9/9/717, 1937.
13
-------
12. Heukelekian, H., and Schulhoff, H. B., "Studies on the
Clarification Stage of the Activated Sludge Process. IV.
Preliminary Notes on the Clarification Organisms in Activated
Sludge", Sewage Works Journal, 10/1 A3, 1938.
13. Ingols, R. S., "Studies on the Clarification Stage of the
Activated Sludge Process. V. Ammonia Uptake", Sewage Works
Journal, 10/1A9, 1938.
H». Heukelekian, H., and Ingols, R. S. "Studies on the Clarification
Stage of the Activated Sludge Process. VI. Hydrolysis of Starch
by Activated Sludge", Sewage Works Journal, 10/3/209, 1938.
15. Dickinson, Denis, "The System of Activated Sludge-Oxygenated
Water, Part IV. Controlled Adsorption", Journal Soc. Chem. Ind.
Trans., 59, pg. 78-80,
16. Ulrich, A. H. , and Smith, M. W. , "The Biosorption Process of
Sewage and Waste Treatment", Journal of the Water Pollution
Control Federation, 23/10/12^*8, 1951.
17- Katz, W. J. and Rohlich, G. A., "A Study of the Equilibrium
and Kinetics of Adsorption by Activated Sludge", Biological
Treatment of Sewage and Industrial Wastes, Reinhold, 1956.
18. Eckenfelder, W. W., "Kinetic Relationship in the Bio-Oxidation
of Sewage and Industrial Wastes", Proc. of the l*»th Purdue Ind.
Waste Conference, pg. ^95, 1959-
19. Siddiqi, R. H. , et al., "The Role of Enzymes in the Contact
Stabilization Process", Journal of the Water Pollution Control
Federation, 38/3/369, 19"6lT
20. Chase, Sherman, "High Rate Activated Sludge Treatment of Sewage",
Journal of the Water Pollution Control Federation, 16/5/878, 19M.
21. Ulrich, A. H. and Smith, M. W. , "Operation Experiences with
Activated Sludge-Biosorpt ion at Austin, Texas", Journal of the
Water Pollution Control Federation, 29AAOO, 1957-
22. Zablatsky, H. R., et al., "An Application of the Principles of
Biological Engineering to Activated Sludge Treatment", Sewage
and Industrial Wastes, 31/11/1281, 1959.
23. Jones, E. L., et al., "Aerobic Treatment of Textile Mill Waste"
Journal of the Water Pollution Control Federation, 3V5A96, 1962.
-------
2l». Atkins, P. R., and Sproul, 0. J., "Feasibility of Biological
Treatment of Potato Processing Wastes", Journal of the Water
Pollution Control Federation, 38/8/128?, 1966.
25. Hinshaw, Conrad S., "Contact Stabilization Plants for Suburban
Areas", Water and Sewage Works. 116/1/12, 1969
26. Daque, R. R., et al., "Contact Stabilization in Small Package
Plants", Journal of the Water Pollution Control Federation,
V*/2/255, 1972.
27. Linsley, R. K. , Kohler, M. A., and Paulhus, J. L., "Hydrology for
Engineers", McGraw-Hill Book Company Inc., 1958.
28. Standard Methods for the Examination of Water and Wastewater,
12th Edition, Amer. Publ. Health Assoc., New York, New York, 1965-
29. United States Weather Service Information.
30. Barnhart, E. L., "Application of Aerobic Digestion to Industrial
Waste Treatment", Proceedings of the 16th Industrial Waste
Conference, Purdue University, p. 612, 1961.
General Reference - "Report on Kenosha Demonstration Project of
Biological Absorption of Pollutants from Combined Storm Water and
Sanitary Sewage", report for the Kenosha Water Utility by Alvord,
Burdick and Howson Engineers, Chicago, Illinois, February, 1970.
15
-------
SECTION X! - PUBLICATIONS
1. Nelson, 0. Fred, and Agnew, Robert W., "Quick, Treatment of
Combined Sewer Overflow Shows Promise", Water and Wastes Engineering,
Vol. 10, No. 8, p. 39 (August 1973).
2. Hansen, Charles A., and Agnew, Robert W., "Two Wisconsin Cities
Treat Combined Sewer Overflows: Biological Treatment in Kenosha",
Water and Sewage Works, Vol. 120, No. 8, p. 48 (August 1973).
116
-------
SECTION XII - GLOSSARY
BOD Biochemical Oxygen Demand - refers to the standard 5 day
Biochemical Oxygen Demand test unless described otherwise.
COD Chemical Oxygen Demand
DWP Dry Weather Plant - this term is used to describe the facilities
present at the Kenosha Water Pollution Control Plant prior to
construction of the demonstration system facilities. It is
also used to describe operation of the treatment plant, after the
demonstration system was installed, during periods of no runoff
when the demonstration system was not in use
F/M Food to Microorganism Ratio - calculated as the rate of BOD load-
ing in kg (Ibs)per day divided by the kg (Ibs) of mixed liquor
suspended solids under aeration in the contact tank on1y.
MLSS Mixed Liquor Suspended Solids - the concentration, mg/1, of
suspended solids under aeration in the contact tank or in the
dry weather plant aeration tanks.
MLVSS Mixed Liquor Volatile Suspended Solids
OUR Oxygen Uptake Rate - refers to the rate of oxygen utilization
(mg/gm/hr or mg/l/hr) by the sludge in the stabilization tank.
RAS Return Activated Sludge - this refers to the sludge from the
normal dry weather plant's return system, or to the settled
sludge from the demonstration system final clarifier during
demonstration system operation.
SS Suspended Sol ids
SVI Sludge Volume Index - this is the volume occupied per gram of•
settled sludge (ml/gm) in settling tests performed in one liter
graduated cylinders.
SOR Surface Overflow Rate - calculated from settling tests using
actual mixed liquor or stabilized sludge and raw sewage, the
settling velocity m/day (ft/day) is multiplied by 1 cu m^/cu ml
(7.48 g/ft3) to develop a volume to area loading rate, cu m/day/
cu m (gpd/ft2).
TOC Total Organic Carbon
VSS Volatile Suspended Solids
WAS Waste Activated Sludge - that portion of the dry weather plants
return activated sludge which is sent directly to the sludge
thickening facilities or to the stabilization tank. Also refers
to the sludge transferred from the stabilization tank to the
sludge thickening facilities when the demonstration system is
not in use.
WPCP Water Pollution Control Plant
117
-------
SECTION XI I I - APPENDICES
APPENDIX A. Description of Analytical Techniques
SM « "Standard Methods for the Examination of Water and
and Wastewater", American Public Health Association,
New York, New York, 12th Ed, 1965, 13th Ed., 1971.
WQO » "Methods for Chemical Analysis of Water and Wastes,
1971", Environmental Protection Agency.
FWPCA - "FWPCA Methods for Chemical Analysis of Water and Wastes,
1969", Federal Water Pollution Control Administration.
Settleable Sol ids
Total Solids
Total Volatile Solids
Suspended Sol ids
Total Organic Carbon and
Dissolved Organic Carbon
1970, SM 12th Ed., p. 422
1972, 1973, SM 13th Ed., P. 500
1970, SM 12th Ed., p. 425
1972, 1973, SM 13th Ed., p. 539.
1970, SM, 12th Ed., p.
1972, 1973, SM, 13th Ed., p. 535
(dried at 105°C)
1970, SM 12th Ed., p. 423 (ignition at
600°C). 1972, 1973, SM 13th Ed., p. 536
(Ignition at 550°C)
1970, SM 12th Ed., p. 424 (asbestos mat in
gooch crucible)
1972, 1972, SM 13th Ed., p. 290 (0.45 v
membrane filter, dried at 105 C)
A portion of the filtrate from filtration
through a washed 0.45 P membrane filter
was used for the COD test. The dilute
COD method was used (p. 4g8, 13th Ed.)
1970, FWPCA, p. 211
1972, 1973, WQO, p. 221
A Model 915 Beck/nan TOC analyzer was used.
118
-------
Total Inorganic Carbon and
Kjeldahl Nitrogen
Total Phosphate
Total Coliform
Fecal Coliform
Suspended Volatile Solids
BOD and Dissolved BOD
The inorganic carbon values from the TOC
and dissolved organic carbon measurements
performed on unacidified samples was used.
1970, FWPCA, p. 145
1972, 1973, WQO, p. 11,9.
Sample digestion: 1970, FWPCA, p. 230
1972, 1973, WQO, p. 242.
Phosphate measurement: 1970, 1972, 1973,
SM 12th Ed., p. 231
1970, "Microbiological Analysis of Water",
Application Report AR-81, Millipore Corp.,
1969, P. 3.
1972, 1973, SM 13th Ed., p. 679
(membrane filter method).
1970, "Microbiological Analysis of Water",
Application Report AR-81, Millipore
Corp., 1969, p. 3
1972, 1973, SM 13th Ed., p. 684
1970, SM 12th Ed., p. 425 (ignition at
600°C).
1972, 1973, SM 13th Ed., p. 292, (ignition
at 550°C)
1970, SM 12th Ed., p. 415.
1972, 1973, SM 13th Ed., p. 498.
1. Chlorinated samples were dechlorinated
with sodium sulfite^ dechlorinatton was
checked by spot-plate using ortho-
tolidine. Excess sulfitewas removed
by aeration. Samples were allowed
to stand 10 minutes after aeration.
2. Dissolved BOD samples were filtered
through washed 0.45 P membrane
filters. The filtrate was dechlorinated
(if necessary) and aerated to restore
D.O.
-------
3. Samples filtered through 0.45 y
membrane filters, and samples that
were dechlorinated were seeded with
1 ml of settled raw sample. Seeded
blanks were also run.
COD and Dissolved COD 1970, SM 12th Ed., p. 510.
1972, 1973, SM 13th Ed., p. J»95.
120
-------
Table
Storm 1 , June 1
Composite sample period, hrs
Parameter
PH
Settleable sol ids
Total solids
Total volatile solids
Suspended solids
Suspended volatile solids
Total "BOD
Dissolved BOD
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col i form
Fecal coliform
Bl.
; Tota
Unit
ml/1
mg/1
mg/l
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
OVERFLOW QUAL
1 Rainfall -
WPCP
0-4
7.4
6.3
814
413
375
259
136
30
507
71
16.8
205,000
1,300
ITY 1970
1.55 cm (0.61 in.)
Site
67th 59th 57th
Street Street Street
6-10
7.3
1.5
471
196
120
40
27
18
117
45
4.3
1,200
1,100
-o
-o
m
z
o
X
CO
•
o
CD
~\
-t>
i
c
01
01
rt
01
-------
Table B2. OVERFLOW QUALITY 1970
Storm 2, June 16; Total Rainfall - 0.58 cm (0.23 in.)
Composite sample period, hrs
Parameter
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
Unit
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
WPCP
0-5.5
7.6
8.5
951
425
388
269
167
32
463
100
185
29
57
52
19.4
9-9
2*1,200
888
Site
67th 59th
Street Street
4-8
7-4
3.5
660
244
234
60
310
98
41
13.0
~57th
Street
1-5
7.5
7-0
595
253
266
145
104
25
257
77
81
23
42
39
7.2
34,000
4,600
-------
Table B3. OVERFLOW QUALITY 1970
Storm 3, June 20; Total Rainfall - 1.73 cm (0.68 in.)
NJ
Composite sample period, hrs
Parameter
PH
Settleabl e sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
Unit
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/m1
#/ml
WPCP
0-4
6.9
8.5
724
420
437
302
140
21
680
69
187
24
25
26
15-1
63
43,000
4,800
Site
67th 59th 57th
Street Street Street
0-4
7.3
0.7
345
147
40
21
36
18
82
53
57
18
48
23
4-3
1.4
9,400
1,530
-------
N)
-C-
Table B4. OVERFLOW Quality 1970
Storm 4, June 26; Total Rainfall - 2.08 cm (0.82 in.)
Composite sample period, hrs
Parameter
PH
Set t leable sol i ds
Tota 1 sol i ds
Total volatile solids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total COD
Dissolved COD
Total organic carbon,
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col i form
Unit
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
WPCP
0-5
7.0
12
1,073
646
890
698
19^
26
1,129
92
21.3
7.8
15,000
2,650
Site
67th 59th 57th
Street Street Street
1-5
7.4
7
642
316
498
316
143
17
295
113
9.2
4.0
3,170
340
-------
Table B5. OVERFLOW QUALITY 1970
Storm 5, July 8; Total Rainfall - 0.89 cm (0.35 in.)
Site
Composite sample period, hrs
Parameter
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col i form
Fecal col i form
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/l
#/ml
#/ml
WPCP
0-4
6.6
18.5
1,966
1,415
1 ,016
728
360
51
2,561
116
12.0
10.7
19,000
2,600
Street
0-4
6.6
9.0
676
363
i»92
266
135
64
419
131
11.6
A. 3
2,000
180
59th
Street3
6.7
1.4
404
202
104
62
46
32
134
103
4.5
0.7
18,000
700
57th
Street
2-6
6.8
27.0
233
21
778
65
24.8
15.1
900
100
a. Grab sample at 3 hours.
-------
Table B6. OVERFLOW QUALITY 1970
Storm 6, July 8; Total Rainfall - O.M cm (0.16 in.)
Composite sample period, hrs.
Parameter
pH
Settleable sol ids
Total solids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal coliform
a. Grab sample at 30 minutes.
b. Grab sample at A5 minutes.
c. Grab sample at A5 minutes.
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/l
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
WPCPa
7.2
2.5
555
195
128
92
86
ko
173
8A
16.3
8.3
17,000
12,000
Site
67th 59th b
Street Street
7.3
1.8
271
102
208
98
50
36
197
83
5.5
3-5
57th
Street
7.1
A.I
5A3
183
116
90
85
37
189
80
15.7
7.8
k] ,000
720
-------
Table B?. OVERFLOW QUALITY 1970
Storm 7, July 13; Total Rainfall - 0.99 cm (0.39 in.)
Composite sample period, hrs.
Parameter
PH
Settleable sol ids
Total solids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col i form
Fecal co li form
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/l
#/ml
#/ml
WPCP
0-4
7-1
14.0
1,196
731
712
508
1,003
147
24.6
4.1
180,000
3,800
Si
67th
Street
0-4
7.0
6.0
661
339
476
260
307
147
10.0
3.7
300,000
8,400
te
59th 57th
Street Street
0-2
7-0
608
297
492
204
266
230,000
22,800
-------
Table B8. OVERFLOW QUALITY 1970
Storm 8, July 19; Total Rainfall - 0.61 cm (0.24 in.)
M
CO
Composite sample periods, hrs.
Parameter
PH
Sett leab le sol ids
Total sol ids
Total volatile solids
Suspended sol i ds
Suspended, volat i le solids
Total BOD
Dissolved BOD
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total collform
Fecal col iform
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
V/PCP
0-4
6.9
5.0
1,123
718
693
530
803
153
310
30
26.6
22.0
78,000
2,400
Site
67th 59th 57th
Street Street Street
0-4
7-3
17.0
354
209
167
83
109
38
41
33
4.4
6.0
1,500
200
-------
Table B9- OVERFLOW QUALITY 1970
Storm 9, July 27; Total Rainfall - 0.69 cm (0.27 in.)
N>
U)
Site
Composite sample period, hrs.
Parameter
PH
Settleable sol ids
Total sol i ds
Total volatile solids
Suspended solids
Suspended volatile solids
Total BOD
Dissolved COD
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kj e 1 dah 1 nit rogen as H
Total phosphorus as P
Total col i form
Fecal coliform
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/l
mg/1
mg/1
mg/l
mg/1
mg/l
mg/l
/7/ml
#/ml
WPCP
0-4
6.9
15-0
1,063
617
975
745
269
52
1,090
132
313
36
27
20
21.0
15.6
6,200
575
67th
Street
o-4
6.9
3.0
443
177
345
195
115
36
290
89
8k
24
18
13
10.0
4.2
4,300
650
59th 57th
Street Street
0-2
7-0
8.0
650
259
434
155
133
48
360
170
124
23
18
8
11.3
4.2
2,500
275
-------
Table BIO. OVERFLOW QUALITY 1970
Storm 10, July 28; Total Rainfall - 1.83 cm (0.72 in.)
Site
Composite sample period, hrs.
Parameter
PH
Settleab le sol i ds
Tota I sol i ds
Total volat i 1 e sol ids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Feca I col iform
Uni ts
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/m1
#/ml
WPCP
0-4
7.5
4.0
598
2^2
217
106
55
155
k2
56
17
37
34
12.0
2.1
2,000
220
67th
Street
0-4
7.4
0.1
230
89
30
52
25
13
62
32
30
12
12
10
3-0
0.6
680
200
59th
Street
0-2
7.5
1 .0
291
126
85
56
28
27
82
54
29
21
13
11
4.2
0.5
220
57th
Street
0-4
7.5
0.5
475
196
114
87
53
40
113
70
52
26
29
22
9.5
1.6
50
-------
Table B11. OVERFLOW QUALITY 1970
Storm 11, July 30; Total Rainfall - 0.3k cm (0.37 in.)
Composite sample periods, hrs.
Parameter
PH
Sett leable sol i ds
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col i form
Feca 1 co 1 i f o rm
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
WPCP
0-4
7.4
4.5
520
262
195
104
70
14
319
46
83
19
32
28
7-7
2.9
15,000
1,400
Site
67th 59th
Street Street
0-4
7.1
3.5
422
245
162
55
66
13
170
48
73
18
16
14
4.9
3.3
17,000
2,400
57th
Street
0-4
7.5
4.5
501
248
212
68
56
11
202
30
64
11
28
26
5.0
6.5
14,000
2,100
-------
Table B12. OVERFLOW QUALITY 1970
Storm 12, August 18; Total Rainfall - 0.84 cm (0.33 in.)
Site
Composite sample period, hrs
Parameter
pH
Settl eable sol ids
Tota 1 sol ids
Total volatile solids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
Units
ml/1
mg/1
mg/1
mg/1
mg/J
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
WPCP
0-0.5
7.2
1,058
719
757
590
1,264
97
260
39
32
24
42,900
34,600
67th
Street
0-0.5
7.5
434
225
171
101
254
97
97
37
20
17
5,200
466
59th
Street
0-0.5
7-3
274
133
46
38
106
74
46
30
17
14
5,400
300
57th
Street
0-0.5
7-7
1 ,422
588
907
514
650
75
264
30
*»3
37
31 ,000
12,075
-------
Table 813- OVERFLOW QUALITY 1970
Storm 13, September 2; Total Rainfall - 1.30 cm (0.51 in.)
Composite sample period, hrs
Parameter
pH
Settleable sol ids
Total sol i ds
Total volatile solids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col i form
Units
ml/1
mg/1
mg/l
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/m1
#/ml
Site
67th 59th 57th
WPCP Street Street Street
0-k
6.9
23
1,683
1,252
1,39*
1,086
251
78
967
105
630
70
17
16. A
8,000
-------
Table Bl'l. OVERFLOW QUALITY 1970
Storm 13B, September 3; Total Rainfall - 0-51 cm (0.20 in.)
Composite sample period, hrs
Parameter
PH
Sett 1 eab le sol ids
Total sol ids
Total volatile solids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
WPCP
Units
ml/1
mg/l
mg/1
mg/l
mg/1
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
#/m 1
8/m]
Site
67th 59th 57th
Street Street Street
1-5
7-4
1.5
386
187
149
78
182
142
49
47
21
19
9.1
19,000
-------
Table 815- OVERFLOW QUALITY 1970
Storm 14, September 3; Total Rainfall - 0.38 cm (0.15 in.)
Composite sample period, hrs
Parameter
PH
Set tl eabl e sol i ds
Total sol i ds
Total volatile solids
Suspended solids
Suspended volatile solids
Total BOD
Dissolved BOD
Total COD
Dissolved COD
Total organic carbon
Disoslved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Tota I col i form
Fecal col i form
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
/Vml
#/ml
Site
67th 59th 57th
WPCP Street Street Street
0-4
7-2
4.5
622
328
221
187
98
27
756
74
156
23
30
10.8
380,000
61 ,000
-------
Table B16. OVERFLOW QUALITY 1970
Storm 15, September 6; Total Rainfall - 2.7k cm (1 .08 in.)
ON
Site
Composite sample period, hrs
Parameter
pH
Sett 1 eab 1 e sol ids
Total sol i ds
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as M
Total phosphorus as P
Total col iform
Fecal col iform
Units
ml/1
mg/1
mg/1
mg/l
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
WPCP
o-4
7.0
7-5
534
313
249
228
110
11
397
r"
5^
113
1 1
23
23
13.8
92,000
40,000
67th
Street
0-4
7-2
6.5
509
280
276
189
76
17
361
61
101
14
18
13
3.8
77,000
6,000
59th
Street
0-2
7.2
6.0
323
319
598
270
75
21
369
62
129
16
14
6
7.4
37,000
1 ,000
57th
Street
0-4
7.1
15.0
1,199
534
905
441
160
18
641
69
260
18
24
15
17.2
160,000
14,000
-------
Table BI7- OVERFLOW QUALITY 1970
Storm 16, September 9; Total Rainfall - 1.73 cm (0.70 in.)
Site
Composite sample period, hrs
Parameter
PH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspende volatile solids
Total BOD
Dissolved COD
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total coliform
Feca 1 col iform
WPCP
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/l
mg/1
mg/1
mg/1
mg/1
mg/1
///ml
#/ml
67th
Street
0-4
7-7
3.5
460
200
394
188
57
18
260
54
93
15
14
12
5.9
9,000
1,500
59th
Street
0-2
7.5
6.5
709
387
610
270
91
23
430
86
120
19
20
16
23,000
2,000
57th
Street
0-4
7.8
10.5
899
329
656
252
107
16
438
46
133
11
35
28
10.3
130,000
6,800
-------
Table BI8. OVERFLOW QUALITY 1970
Storm 17, September \k; Total Rainfall - 2.2k cm (0,88 in.)
Site
Composite sample period, hrs
Parameter
pH
Settleable sol ids
Total sol i ds
Total volatile solids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
WPCP
o-k
7.0
23.0
1,260
877
910
707
266
908
60
232
18
2k
20
19.3
300,000
26,000
67th
Street
3-7
7-3
2.3
503
206
172
104
73
255
50
73
16
27
2k
6.8
6,000
2,800
59th 57th
Street Street
3.5-7-5
7.6
8.5
9^3
352
550
22*4
153
382
48
123
15
*»5
35
12.8
21 ,000
3,700
-------
Table B19. OVERFLOW QUALITY
Storm 13, September 15; Total Rainfall -
1970
1.37 cm (0.54 in.)
oo
"oO
Site
Composite sample period, hrs
Parameter
PH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col i form
Fecal col i form
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/m1
WPCP
0-4
7.3
8.0
660
385
320
207
135
33
334
72
120
25
32
27
133,000
20,000
67th
Street
0-4
7.1
516
226
249
119
71
313
89
22
22,000
4,100
59th
Street
0-2
6.6
482
259
320
178
1 10
324
104
11
33,000
1,100
57th
Street
0-4
6.4
1,360
782
972
647
302
1,045
480
16
25,000
17,000
-------
Storm 19,
Table 1320.
September 1
Composite sample period, hrs
Parameter
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended solids
Suspended volatile solids
Total BOD
Dissolved BOD
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
OVERFLOW QUALI
5; Total Rainfal
WPCP
0-4
7-2
8,5
636
324
403
241
141
40
345
32
128
11
20
19
37,000
4,400
TY 1970
1 - 1-37 cm (0.
Site
67th
Street
0-4
7.1
519
192
307
134
67
205
77
16
19,300
1,850
54 in.)
59th
Street
0-2
7.3
359
198
307
100
19
30,600
3,900
57th
Street
0-4
6.9
922
504
637
395
236
742
288
24
51 ,000
26,000
-------
Table B21. OVERFLOW QUALITY 1970
Storm 20, September 17; Total Rainfall - 6.07 cm (2.39 in.)
Composite sample period, hrs
Parameter
PH
Settl eable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total COD
Dissolved BOD
Total COD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col i form
Fee la col iform
WPCP
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/m1
Si
67th
Street
3-7
7-2
1.5
507
262
378
206
40
12
279
33
62
11
19
14
3-4
2,200
200
te
59th
Street
5.5-7.5
7.7
619
351
344
240
66
283
49
79
14
24
21
2,650
100
57th
Street
3-7
7.3
12.0
899
504
555
288
140
11
404
34
152
12
21
13
13.9
76,500
28,500
-------
Table B22. OVERFLOW QUALITY 1970
Storm 21, September 22, Total Rainfall - 1.2*1 cm (0.^9 in.)
Site
WPCP
67th
Street
59th
Street
57th
Street
Composite sample period, hrs
Parameter
Units
PH
Settleable sol ids ml/1
Total sol ids mg/1
Total volatile solids mg/1
Suspended solids mg/1
Suspended volatile solids mg/1
Total BOD mg/1
Dissolved BOD mg/1
Total COD mg/1
Dissolved COD mg/1
Total organic carbon mg/1
Dissolved organic carbon mg/1
Total inorganic carbon mg/1
Dissolved inorganic carbon mg/1
Kjeldahl nitrogen as N mg/1
Total phosphorus as P mg/1
Total coliform #/ml
Fecal coliform #/ml
-------
Storm 22,
Composite sample period,
Parameter
PH
Settleable sol ids
Total sol i ds
Total volatile solids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total COD
Dissolved COd
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Table B23.
September 23;
hrs
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
Dissolved inorganic carbon mg/1
Kjeldahl nitrogen as N
Total phosphorus as P
Total col i form
Fecal coli form
mg/1
mg/1
#/ml
#/ml
OVERFLOW QUALITY
Total Rainfall -
WPCP
0-4
7.4
10.5
771
146
470
332
163
15
410
51
170
18
46
35
15.4
126,000
11 ,000
1970
3.51 cm (1.38 in.)
Site
67th 59th 57th
Street Street Street
0-4
7.8
2.2
451
170
209
89
44
11
167
38
53
11
27
25
5.7
37,500
1,850
-------
Table B24. OVERFLOW QUALITY 1970
Storm 23, September 25; Total Rainfall - 0.91 cm (0.36 in.)
Site
Composite sample period, hrs
Parameter
pH
Settleable sol i ds
Total sol ids
Total volatile sol Ida
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOd
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
vmg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
vypcp
0-4
7.1
5.5
633
302
229
129
83
9
323
41
115
17
42
39
10.8
88,000
1 ,400
67th
Street
0.5-4.5
7.6
3.5
541
207
238
96
49
12
162
40
57
12
35
30
5.2
205,000
1,550
59th
Street
0-4
7.2
617
468
343
229
138
618
49
188
16
28
56
33,500
1 ,600
57th
Street
0.5-4.5
8.0
1 ,774
822
1,377
648
361
1,106
63
35
30
19
40
840,000
52 ,000
-------
Table B25. OVERFLOW QUALITY 1970
Storm 2k, October 1A; Total Rainfall - l.OA cm (0.41 in.)
Composite sample period, hrs
Parameter
PH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOd
Total COD
Dissolved COD
Total organic carbon
Dissolved organic carbon
Total inorganic carbon
Dissolved inorganic carbon
Kjeldahl nitorgen as N
Total phosphorus as P
Total col iform
Fecal col i form
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/m1
#/ml
Site
67th 59th 57th
WPCP Street Street Street
1.0-5.0
7.1
17-5
932
653
618
kSk
333
29
702
73
276
25
28
19
17-9
65,000
7,000
-------
Table Cl. OPERATING DATA FOR RUM NO.
General TJ
-o
Date: April 12, 1972 o
Start: 7:30 pm Stop: 10:20 pm Duration: 2.33 hours x
Volume treated: 6,805 cu m (1,798,000 gallons) o
Average flow rate: 59,614 cu m/day (15.75 mgd)
Average transfer rate: 17,903 cu m/day (4.73 mgd) Percent return; 30 o
Average dry weather plant flow rate: 71,9'5 cu m/day (19 mgd) 3
o
3
Contact Tank £
o>
HLSS: 4,940 mg/1 Contact time3: 17-20 min 1.
BOD loading: 15', 184 g/cu m/day (949 lb/day/1000 ft3) °
F/Hb: 3.10 kg BOD/day/kg MLSS Air flow: 82.7 cu m/min (2953 cfm)
Air supply: 10.7 cu m/kg BOD applied (173 ft3/lb BOD applied) ^
rt
Stabilization Tank
o
-a
Stabilization time0: 7 days - S Reaeration time: 2.95 hours n
Stabilization tank turnovers: 0.93 "
Oxygen supply: 454 kg/hr (1000 Ib/hr) 3*
Final Clarifier a?
01
Surface overflow rate: 41.7 cu m/day/sq m (1023 gpd/ft^)
Clarifier detention time3: 1.60 hours Clarifier turnovers: 1.71
Clarifier solids loading: 267,424 g/day/sq m (54.8 lb/day/ft2)
a. Based on total flow.
b. Cased on HLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table Cl (continued). OPERATING DATA FOR RUN NO. 1
Grit Contact Stabilization DWP Final Percent
Characteristics Un? ts tank tank tank clarifier clarifier removal
pH
Settleable sol ids ml/1
Total sol ids mg/1
Total volatile solids mg/1
Suspended solids mg/J 1035 ^0 20 98.1
Suspended volatile solids mg/1
Total 800 mg/1 237 25 89-5
Dissolved BOD mg/1
Total organic carbon mg/1 355 23 93.5
Dissolved organic carbon mg/1
Kjeldahl nitrogen as N mg/1
Total phosphorus as P mg/1
Total coliform ff/m\
Fecal coliform #/ml
-------
Table C2. OPERATING DATA FOR RUN NO. 2
General
Date: April 14, 1972 to April 15, 1972
Start: 11:35 pm Stop: 4:40 am Duration:
4.75 hours
Volume treated: 13,066 cu m (3,452,000 gallons)
Average flow rate: 65,859 cu m/day (17-4 mgd)
Average transfer rate: 23,051 cu m/day (6.09 mgd) Percent return; 30
Average dry weather plant flow rate: 75,700 cu m/day (20 mgd)
Contact Tank
MLSS: 5,370 mg/1 Contact time3: 14.99 min
BOD loading: 10,272 g/cu m/day (642 lb/day/1000 ft3)
F/Mb: 1.92 kg BOD/day/kg MLSS Air flow: 91.3 cu m/min (3262 cfm)
Air supply: 7.3 cu m/kg BOD applied (119 ft3/lb BOD applied)
Stabilization Tank
Stabilization timec: 2.0 days - S Reaeration time: 1.77 hours
Stabilization tank turnovers: 2.67 OUR:
Oxygen supply: 454 kg/hr (1000 Ib/hr)
Final Clarifier
Surface overflow rate: 46.1 cu m/day/sq m (1130 gpd/ft )
Clarifier detention time3: 1.41 hours Clarifier turnovers: 3.36
Clarifier solids loading: 333,304 g/day/sq m (68.3 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. 5 = static condition; C = continuous flow.
-------
Table C2 (continued). OPERATING DATA FOR RUN NO. 2
-C-
UD
Characteristics
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col 5 form
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/l
mg/1
mg/1
#/ml
#/ml
Grit
tank
7.6
925
435
515
150
145
14
20k
15
16.9
9.3
68000
3500
Contact Stabilization DWP Final
tank tank clarifier clarifier
2.05
416
128
5370 9375 40 14
3780 4775 7
44 17
6
18
12
7.3
2.9
3100
1220
Percent
remova I
77.2
55.0
70.3
97.3
95.3
88.3
57.1
91.2
20.0
56.8
68.8
95.4
65.1
-------
Table C3. OPERATING DATA FOR RUN NO. 3
General
VJ1
o
Date: April 16, 1972
Start: 8:33 am Stop: 4:56 pm Duration: 8:33 hours
Volume treated: 20,818 cu m (5,500,000 gallons)
Average flow rate: 59,803 cu m/day (15.8 mgd)
Average transfer rate: 26,911 cu m/day (7.11 mgd) Percent return: 45
Average dry weather plant flow rate: 83,270 cu m/day (22 mgd)
Contact Tank
MLSS: 2,650 mg/1 Contact time3: 15-37 min
BOD loading: 4,496 g/cu m/day (281 lb/day/1000 ft3)
F/Mb: 1.71 kg BOD/day/kg MLSS Air flow: 82.9 cu m/min (2962 cfm)
Air supply: 21.6 cu m/kg BOD applied (351 ft3/lb BOD applied)
Stabilization Tank
Stabilization time0: 2.0 days - S Reaeration time:
Stabilization tank turnovers: 6.2 OUR:
Oxygen supply: 454 kg/hr (1000 Ib/hr)
1 .35 hours
Final Clarifier
ry
Surface overflow rate: 41.9 cu m/day/sq m (1026 gpd/ft )
Clarifier detention time3: 1.45 hours Clarifier turnovers: 5-8
Clarifier solids loading: 160,552 g/day/sq m (32.9 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C3 (continued). OPERATING DATA FOR RUN NO. 3
Characteristics
PH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
Grit Contact
tank tank
7.6
4.5
587
231
380 2650
218 1050
70
10
69
14
9.5
4. 44
3500
220
Stabilization DWP Final
tank clarifier clarifier
Trace
406
15*
7530 26A 14
3750 0
80 9
2
15
10
3.7
1.08
>7
32
Percent
remova 1
30.8
33-3
96.3
100.0
87.1
80.0
78.2
28.6
61.1
75.7
<99-8
85.5
-------
Table C4. OPERATING DATA FOR RUN NO. 4
General
Date: April 21, 1972
Start: 10:53 am Stop: 5:35 pm Duration: 6.70 hours
Volume treated: 19,671 cu m (5,197,000 gallons)
Average flow rate: 73,240 cu m/day (19-35 mgd)
Average transfer rate: 36,601 cu m/day (9-67 mgd) Percent return; 50
Average dry weather plant flow rate: 37,850 cu m/day (10 mgd)
Contact Tank
MLSS: 2,000 mg/1 Contact time3: 12.13 min
BOD loading: 5,82** g/cu m/day (364 lb/day/1000 ft3)
F/Mb: 2.94 kg BOD/day/kg MLSS Air flow: 101.6 cu m/min (3628 cfm)
Air supply: 27.9 cu m/kg BOD applied (452 ft3/lb BOD applied)
Stabilization Tank
Stabilization time : 5.0 days = S
Stabilization tank turnovers: 6.3
Oxygen supply: 397 kg/hr (875 lb/hr)
Reaeration time:
OUR:
0.99 hours
Final Clarifier
Surface overflow rate: 51-3 cu m/day/sq m (1257 gpd/ft )
Clarifier detention time3: 1.14 hours Clarifier turnovers: 5-86
Clarifier solids loading: 153,720 g/day/sq m (31.5 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C4 (continued). OPERATING DATA FOR RUN NO. 4
Characteristics
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kj el da hi nitrogen as N
Total phosphorus as P
To ta 1 co 1 i f o rm
Fecal col 5 form
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
Grit Contact
tank tark
7.0
5
802
252
22*4 ^000
119 H27
74
23
81
28
1*4.9
7.18
2900
68
Stabilization DWP Final
tank clarifier clarifier
Trace
618
78
6965 24 40
3989 25
16 21
9
22
16
8.4
3.52
83
60
Percent
remova 1
22.9
69.0
82.1
79.0
71.6
67-8
72. 8
42.8
43.6
51.0
97.1
11.7
-------
Table C5- OPERATING DATA FOR RUN NO. 5
General
Date: May 6, 1972
Start: 4:00 am Stop: 7:02 am Duration: 3-03 hours
Volume treated: 7,593 cu m (2,006,000 gallons)
Average flow rate: 60,560 cu m/day (16.0 mgd)
Average transfer rate: 21,196 cu m/day (5.6 mgd) Percent return; 35
Average dry weather plant flow rate: 7l,9'5 cu m/day (19 mgd)
_ Contact Tank _
MLSS: 986 mg/1 Contact time3: 16.31 min
BOD loading: 4,160 g/cu m/day (260 lb/day/1000 ft3)
F/Mb: 4.26 kg BOD/day/kg MLSS Air flow: 8^4.0 cu m/min (3000 cfm)
Air supply: 39.0 cu m/kg BOD applied (632 ft3/lb BOD applied)
_ Stabi 1 izat ion Tank _
Stabilization time0: 15.0 days - S Reaeration time: 1.88 hours
Stabilization tank turnovers: 1.61 OUR:
Oxygen supply: 397 kg/hr (875 lb/hr)
_ Final Clarifier _
Surface overflow rate: k2.k cu m/day/sq m (1039 gpd/ft )
Clarifier detention timea: 1.5^ hours Clarifier turnovers: 1.97
Clarifier solids loading: 56,120 g/day/sq m (11.5 Ib/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C5 (continued). OPERATING DATA FOR RUN NO. 5
Characteristics
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended solids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total Phosphorus as P
Total col if orm
Fecal col if orm
Units
ml/1
mg/l
mg/1
mg/l
mg/1
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
#/m!
#/ml
Grit
tank
7.55
7.4
517
215
155
78
6k
41
89
34
10.8
3.39
3800
500
Contact Stabilization DWP Final
tank tank clarifier clarifier
Trace
490
145
986 14 15
548 7
18 18
12
21
17
5.2
1.86
2600 2700
520 700
Percent
remova 1
5.2
32.6
90.5
91 .0
72.0
70.7
76.4
50.0
51.8
45.1
28.9
-------
Table C6. OPERATING DATA FOR RUN NO. 6
General
Date: May 8, 1972
Start: 4:04 pm Stop: 10:30 pm Duration: 6.48 hours
Volume treated: 17,824 cu m (4,709,000 gallons)
Average flow rate: 66,6l6 cu m/day (17-6 mgd)
Average transfer rate: 26,646 cu m/day (7.04 mgd) Percent return; 40
Average dry weather plant flow rate: 75,700 cu m/day (20 mgd)
Contact Tank
MLSS: 975 mg/1 Contact time3: 14.29 min
BOD loading: 5,088 g/cu m/day (318 lb/day/1000 ft3)
F/Hb: 5.26 kg BOD/day/kg MLSS Air flow: 92.4 cu m/min (3300 cfm)
Air supply: 31-9 cu m/kg BOD applied (518 ft3/lb BOD applied)
Stabilization Tank
Stabilization timec: 2.0 days - S
Stabilization tank turnovers: 3-77
Oxygen supply: 397 kg/hr (875 Ib/hr)
Reaeration time:
OUR:
r.70 hours
Final Clarifier
o
Surface overflow rate: 46.6 cu m/day/sq m (1143 gpd/ft )
Clarifier detention time3: 1.35 hours Clar-fier turnovers: 4.77
Clarifier solids loading: 63,440 g/day/sq m (13.0 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C6 (continued). OPERATING DATA FOR RUN NO. 6
Cha racter ist ics
pH
Settl eable sol ids
Total sol i ds
Total volatile solids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mq/l
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
Grit Contact
tank tank
7.58
2.0
597
323
110 975
45 470
71
39
107
29
10.1
5-15
17000
525
Stabilization DWP Final
tank clarifier clarifier
Trace
548
264
14 28
6 13
15 23
9
26
16
7.4
4.36
850 470
500 250
Percent
removal
8.2
19.5
74.5
71.1
67. 6
76.9
75.7
44.8
26.7
15.3
97-5
52.4
-------
Table C7- OPERATING DATA FOR RUN NO. 7
Genera 1
Date: May 13, 1972
Start: 10:53 am Stop: 3=34 pm Duration: 4.60 hours
Volume treated: 10,352 cu m (2,867,000 gallons)
Average flow rate: 54,332 cu m/day (14.5 mqd)
Average transfer rate: 30,015 cu m/day (7-93 mgd) Percent return; 55
Average dry weather plant flow rate: 75,700 cu m/day (20 mgd)
Contact Tank
HLSS: 1,387 mg/1 Contact time3: 15-70 min
- BOD loading: 6,016 g/cu in/day (376 lb/day/1000 ft3)
00 F/Hb: 3-21 kg 30D/day/kg MLSS Air flow: 76.1 cu m/min (2719 cfm)
Air supply: 27-0 cu m/kg BOD applied (438 ft3/lb 300 applied)
Stabilization Tank
Stabilization timec: 5-0 days - S
Stabilization tank turnovers: 3- '7
Oxygen supply: 340 kg/hr (750 Ib/hr)
Reaeration time:
OUR:
1 .45 hours
Final Clarifier
Surface overflow rate: 33-4 cu m/day/sq m (942
Clarifier detemtion time3: 1.48 hours Clarifier turnovers: 3.11
Clarifier solids loading: 111,752 g/day/sq m (22.9 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C7 (continued). OPERATING DATA FOR RUN NO. 7
un
UD
Character i st i cs
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kj el da hi nitrogen as N
Total phosphorus as P
Total col iform
Feca 1 co 1 i f o rm
Units
ml/1
mg/1
mg/1
mg/l
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/m1
Grit Contact
tank tank
7.5
9
738
300
257 1887
100 1077
102
19
107
27
17.3
7.4
2250
950
Stabilization DWP Final
tank clarifier clarifier
Trace
544
161
25
11
14
6
24
18
7.2
3.6
1350
715
Percent
remova 1
26.3
46.3
90.3
89.0
86.3
68.4
77. 5
33.3
58.4
51.4
40.0
24.7
-------
Table C8. OPERATING DATA FOR RUN NO. 8
General
Date: May 15, 1972
Start: 11:45 am Stop: 2:56 pm Duration: 3-13 hours
Volume treated: 3,353 cu m (2,207,000 gallons)
Average flow rate: 62,982 cu m/day (16.6*4 mgd)
Average transfer rate: 32,750 cu m/day (8.65 mgd) Percent return; 52
Average dry weather plant flow rate: 75,700 cu m/day (20 mgd)
Contact Tank
MLSS: 2,161 mg/1 Contact time3: 13.92 min
BOD loading: 10,080 g/cu m/day (630 lb/day/1000 ft3)
F/Mb: 4.70 kg BOD/day/kg MLSS Air flow: 87.4 cu m/min (3120 cfm)
Air supply: 16.3 cum/kg BOD applied (265 ft3/lb BOD applied)
Stabilization Tank
Stabilization timec: 2.0 days - S Reaeration; time: 1.46 hours
Stabilization tank turnovers: 2.18 OUR:
Oxygen supply: 340 kg/hr (750 Ib/hr)
Final Clarifier
2
Surface overflow rate: 44.1 cu m/day/sq m (1081 gpd/ft )
Clarifier detention time3: 1.31 hours Clarifier turnovers: 2.43
Clarifier solids loading: 144,448 g/day/sq m (29.6 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C8 (continued). OPERATING DATA FOR RUN NO. 8
Characteristics
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col i form
Fecal col iform
Units
ml/1
mg/1
mg/1
mg/1
mg/l
mg/1
mg/1
mg/1
mg/1
mg/1
mg/l
#/ml
#/ml
Grit Contact
tank tank
8
786
283
266 2161
154 123**
149
57
J38
45
20.1
12.04
10300
1500
Stabilization DWP Final
tank clarifier clarifier
Trace
561
185
14 28
17
10 22
8
29
19
8.1
4.8
85 2050
<4 1300
Percent
remova 1
26.1
34.6
89.5
88.9
85.2
85.9
78.9
57.7
59.7
60.1
80.1
13.3
-------
Table C9- OPERATING DATA FOR RUN MO. 9
OS
General
Date: June 2, 1972 to June 3, 1972
Start: 10:10 pm Stop: 7=55 am Duration: 8.72 hours
Volume treated: 18,282 cu m (4,830,000 gallons)
Average flow rate: 50,340 cu m/day (13-3 mgd)
Average transfer rate: 17,638 cu m/day (4,66 mgd) Percent return; 35
Average dry weather plant flow rate: 56,775 cu m/day (15 mgd)
Contact Tank
MLSS: 2,700 mg/1 Contact time3: 19.62 min
BOD loading: 13,088 g/cu m/day (818 lb/day/1000 ft3)
F/Mb: 4.89 kg BOD/day/kg MLSS Air flow: 69.8 cu m/min (2494 cfm)
Air supply: 12.4 cu m/kg BOD applied (201 ft^/lb BOD applied)
Stabi1i zat ion Tank
Stabilization timec: 2.0 days - S
Stabilization tank turnovers: 3-25
Oxygen supply: 284 kg/hr (625 lb/hr)
Reaeration time:
OUR:
2.68 hours
Fi nal Clari fi er
Surface overflow rate: 35.3 cu m/day/sq m (364
Clarifier detention time3: 1.85 hours Clarifier turnovers: 4.72
Clarifier solids loading: 128,344 g/day/sq m (26.3 Ib/day/ft )
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C9 (continued). OPERATING DATA FOR RUN NO. 9
Characteristics
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
Units
ml/1
mg/1
mg/1
mg/1
mg/l
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
Grit Contact
tank tank
7.05
26
1265
650
920 2700
320 1400
2k2
62
205
43
7
26000
1300
Stabilization DWP Final
tank clarifier clarifier
Trace
446
138
15700 11 41
10100 22
26 30
21
36
31
4
4700
1100
Percent
removal
64.7
78.7
95.5
93.1
87.6
66.1
87.8
27-9
42.8
81.9
15.4
-------
Table CIO. OPERATING DATA FOR RUN NO. 10
General
Date: June 12, 1972
Start: 9:21 am Stop: 12:21 pm Duration: 3-00 hours
Volume treated: 8,005 cu m (2,115,000 gallons)
Average flow rate: 64,042 cu m/day (16.92 mgd)
Average transfer rate: 26,874 cu m/day (7-'0 mgd) Percent return; 42
Average dry weather plant flow rate: 64,345 cu m/day (17 mgd)
_ Contact Tank _
MLSS: 2,625 mg/1 Contact time3: 14.65 min
BOD loading: 10,320 g/cu m/day (645 lb/day/1000 ft3)
F/Mb: 3,96 kg BOD/day/kg MLSS Air flow: 88.8 cu m/min (3172 cfm)
Air supply: 13-3 cu m/kg BOD applied (216 ft3/1b BOD applied)
Stabi 1 izat ion Tank
Stabilization timec: 9-0 days - S
Stabilization tank turnovers: 1.48
Oxygen supply: 284 kg/hr (625 Ib/hr)
Reaeration time:
OUR:
2.02 hours
Final Clarifier
Surface overflow rate: 44.8 cu m/day/sq m (1099 gpd/ft )
Clarifier detention time3: 1.38 hours Clarifier turnovers: 2.17
Clarifier solids loading: 166,896 g/day/sq m (34.2 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table CIO (continued). OPERATING DATA FOR RUN NO. 10
ON
Character is ti cs
pH
Sett leable sol ids
Tota 1 sol ids
Total volat i le sol ids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjel dan 1 nitrogen as N
Total phosphorus as P
Tota 1 col i form
Fecal co! iform
Units
ml/1
mg/l
nig/1
mg/l
mg/l
mg/l
mg/l
mg/l
mg/l
mg/1
mg/l
#/ml
#/ml
Grit
tank
7.2
11 .8
770
345
417
215
150
35
163
33
17.6
5.1
28000
1300
Contact Stabilization DWP
tank tank clarifier
6.9 7.15 7.65
Trace
462
148
2625 7625 5
1550 4500 4
1820 8
8
1838 13
13
10.2
3.3
35
Fi nal
clari fier
Trace
446
158
15
10
15
13
27
20
10.5
5.0
1720
Percent
remova 1
42.1
54.2
96. A
95-3
90.0
62.8
83.4
39.4
40.3
1 -9
4.4
-------
Table Cll. OPERATING DATA FOR RUN NO. 1)
General
Date: June 14, 1972
Start: 2:23 pm Stop: 5:13 pro Duration: 2.74 hours
Volume treated: 7,604 cu m (2,009,000 gallons)
Average flow rate: 66,616 cu m/day (\7.(> mgd)
Average transfer rate: 29,977 cu m/day (7-Q2 rngd) Percent return; 45
Average dry weather plant flow rate: 64,345 cu m/day (17 mgd)
Contact Tank
MLSS: 2,425 mg/1 Contact timea: 13.80 min
300 loading: 6,592 g/cu m/day (412 lb/day/1000 ft3)
F/Mb: 2.67 kg BOD/day/kg MLSS Air flow: 92.4 cu m/min (3300 cfm)
Air supply: 21.7 cu m/kg BOD applied (352 ftVlb BOD applied)
Stabilization Tank
Stabilization timec: 2.0 days - S Reaeration time: 1.88 hours
Stabilization tank turnovers: 1.46 OUR:
Oxygen supply: 284 kg/hr (625 Ib/hr)
Final Clarifier
f\
Surface overflow rate: 46.6 cu m/day sq m (1143 gpd/ft )
Clarifier detention time : 1.30 hours Clarifier turnovers:
Clarifier solids loading: 163,480 g/day/sq m (33-5 1b/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table Cll (continued). OPERATING DATA FOR RUN NO. 11
Character i sties
pH
Settleable sol ids
Total sol ids
Total volat i le sol ids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col i form
Feca 1 col i form
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/m1
Grit Contact
tank tank
2.8
669
252
166 2425
117 1750
92
62
91
49
13.5
5.69
57000
400
Stabi 1 ization DWP
tank clarifier
Trace
378
120
12975 8
7850 3
2800 12
6
4450 15
12
5.1
0.26
520
29
Final
clar i f ier
Trace
459
130
7
3
16
13
2k
19
8.3
1.41
2100
29
Percent
removal
3K4
48.4
95.7
97.4
82.6
79.0
73.6
61.2
38.5
75.2
96.3
92.8
-------
Table C12. OPERATING DATA FOR RUN NO. 12
oo
General
Date: June 19, 1972 to June 20, 1972
Start: 8:10 pm Stop: 3:40 am Duration: 7-47 hours
Volume treated: 19,387 cu m (5,122,000 gallons)
Average flow rate: 62,301 cu m/day (16.46 mgd)
Average transfer rate: 23,047 cu m/day (7-4l mgd) Percent return; 45
Average dry weather plant flow rate:
_ Contact Tank _
MLSS: 2,325 mg/1 Contact timea: 14.76 min
BOD loading: 3,744 g/cu m/day (234 lb/day/1000 ft3)
F/Mb: 1.34 kg/BOD/day/kg MLSS Air flow: 36.4 cu m/min (3086 cfm)
Air supply: 35.6 cu m/kg BOD applied (578 ft^/lb BOD applied)
Stab i 1 i zat ion Tank
Stabilization timec: 5.0 days - S
Stabilization tank turnovers: 3-72
Oxygen supply: 284 kg/hr (625 Ib/hr)
Reaeration time:
OUR:
2,01 hours
Fina1 Clarif ier
Surface overflow rate: 43.6 cu m/day/sq m (1069 gpd/ft )
Clarifier detention timea: 1.39 hours Clarifier turnovers: 5-37
Clarifier solids loading: 178,120 g/day/sq m (36.5 1b/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C12 (continued). OPERATING DATA FOR RUN NO. 12
Character! st i cs
PH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended so 1 i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col i form
Fecal col iform
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/m1
#/ml
Grit Contact
tank tank
7.30 7.05
3.0
Ski
161
213 2325
78 1725
56
28
6k
20
7.27
2.23
13500
1050
Stabilization DWP
tank clarifier
6.95 7.70
Trace
433
76
13575 12
8110 9
2500 17
1 1
4250 17
16
7.19
3.26
650
25
Final
clarifier
7.40
Trace
370
107
20
17
17
16
2k
16
5.87
2.37
5900
460
Percent
removal
32.3
33.5
90.6
78.2
69.6
42.8
62.5
20.0
19.3
56.3
56.2
-------
Table CI3- OPERATING DATA FOR RUN NO, 13
General
Date: July 12, 1972 to July 13, 1972
Start: 11:05 pm Stop: 2:03 am Duration: 2.36 hours
Volume treated: 7,555 cu m (1,996,000 gallons)
Average flow rate: 61,317 cu m/day (16.2 mgd)
Average transfer rate: 15,329 cu m/day (4.05 mgd) Percent return; 25
Average dry weather plant flow rate:
Contact Tank
MLSS: 3,950 mg/1 Contact time3: I7,39min
BOD loading: 9,824 g/cu m/day (614 1b/day/1000 ft3)
F/Mb: 2.50 kg BOD/day/kg MLSS Air flow: 85.! cu m/min (3038 cfm)
Air supply: 13.4 cu m/kg BOD applied (213 ftVlb BOD applied)
^ Stabi 1 i zat ion Tank
Stabilization timec: 14,0 days - S Reaeration time: 3-08 hours
Stabilization tank turnovers: 0.96 OUR:
Oxygen supply: 340 kg/hr (750 Ib/hr)
Final Clarifier
2
Surface overflow rate: 42.9 cu m/day/sq m (1052 gpd/ft )
Clarifier detention time3: 1.64 hours Clarifier turnovers: 1.81
Clarifier solids loading: 211,304 g/day/sq m (43-3 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C13 (continued). OPERATING DATA FOR RUN NO. 13
Character ist i cs
pH
SettI cable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal co 1 if orm
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
Grit Contact
tank tank
6.85 6.70
11
724
362
^79 3950
269 2350
149
41
161
33
13.2
4.76
40000
13000
Stabilization DWP
tank clarifier
6.98 7.52
Trace
463
112
14775 34
8900 27
3250 30
10
4550 20
15
7.1
2.07
11000
1300
Final
clar if ier
7-21
Trace
439
190
49
22
49
22
48
31
11.2
6.39
23300
600
Percent
remova 1
32.4
47.5
89.7
91.8
73.2
46.3
70.2
6.1
15.2
41.7
95.4
-------
Table C14. OPERATING DATA FOR RUN NO. 14
General
Date: July 13, 1972
Start: 10:02 am Stop: 7:32 pm Duration: 9.56 hours
Volume treated: 24,640 cu m (6,510,000 gallons)
Average flow rate: 61,696 cu m/day (16.3 rngd)
Average transfer rate: 25,284 cu m/day (6.68 mgd) Percent return; 42
Average dry weather plant flow rate:
Contact Tank
MLSS: 3,525 mg/1 Contact time3: 15-32 min
3^
BOD loading: 6,496 g/cu m/day (406 lb/day/1000 ft )
F/Mb: 1.86 kg BOD/day/kg MLSS Air flow: 85.6 cu m/min (3056 cfm)
Air supply: 20.4 cu m/kg BOD applied (331 ftVlb BOD applied)
Stabilization Tank
Stabilization timec: 0.5 days - S Reaeration time: 2.15 hours
Stabilization tank turnovers: 4.43 OUR: 48 mg/l/hr
Oxygen supply: 3^0 kg/hr (750 Ib/hr)
Fi nal Clari f i er
f\
Surface overflow rate: 43.2 cu m/day/sq m (1058 gpd/ft )
Clarifier detention time3: 1.44 hours Clarifier turnovers: 6.62
Clarifier solids loading: 214,232 g/day/sq m (43.9 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C14 (continued). OPERATING DATA FOR RUN NO. 14
Characterist i cs
pH
Sett 1 eabl e sol i ds
Total sol ids
Total volatile solids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col i form
Fecal col iform
Units
ml/l
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
Grit Contact
tank tank
4.5
628
227
310 3525
121 1825
98
15
140
19
13.3
4.98
795000
600
Stabilization DWP
tank clarifier
Trace
367
112
12650 33
7125 23
2450 10
8
3950 18
13
2.1
0.75
104000
320
Final
clarifier
Trace
360
118
25
13
22
6
21
18
5.7
1.41
157000
770
Percent
remova I
42.6
48.0
91.9
89.3
77.6
60.0
85.0
5.3
57.1
71.7
80.3
-------
Table CIS. OPERATING DATA FOR RUN NO. 15
General
Date: July 14, 1972 to July 15, 1972
Start: 11:03 pm Stop: 8:26 am Duration:
Volume treated: 24,023 cu m (6,347,000 gallons)
Average flow rate: 6l,3'7 cu m/day (16.2 mgd)
Average transfer rate: 13,395 cu m/day (4.86 mgd)
Average dry weather plant flow rate:
Contact Tank
9.38 hours
Percent return; 30
MLSS: 4,325 mg/1 Contact time3: 16.72 min
BOD loading: 2,896 g/cu m/day (181 lb/day/1000 ft3)
F/Mb: 0.68 kg BOD/day/kg MLSS Air flow: 85.! cu m/min (3038 cfm)
Air supply: 44.8 cu m/kg BOD applied (727 ft3/lb BOD applied)
Stabilization Tank
Stabilization time0: 1.0 days - S Reaeration time: 2.96 hours
Stabilization tank turnovers: 3-16 OUR: 52 mg/l/hr
Oxygen supply: 340 kg/hr (750 Ib/hr
Final Clarifier
O
Surface overflow rate: 42.9 cu m/day/sq m (1052 gpd/ft )
Clarifier detention time3: 1.57 hours Clarifier turnovers: 5-96
Clarifier solids loading: 240,584 g/day/sq m (49-3 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table CIS (continued). OPERATING DATA FOR RUN NO. 15
Character ist ics
pH
Settleable sol ids
Total solids
Total volatile solids
Suspended solids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total coliform
Fecal col iform
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
///ml
#/ml
Grit
tank
7.67
3.5
682
195
334
62
44
8
64
13
6.55
2.46
8700
6400
Contact Stabilization DV/P
tank tank clarifier
7-70
Trace
432
124
4325 14775 13
2350 7575 1
2550 23
4
4850 24
12
3.6
2.38
2600
1100
Final
clarifier
7.70
Trace
372
100
10
5
8
4
14
12
2.7
1.96
1300
1200
Percent
removal
45.4
48.7
97.0
91.9
81.8
50.0
78.1
7-7
58.8
20.3
85.0
81.3
-------
Table Clb. OPERATING DATA FOk RUN NO. 16
Genera 1
Date: July 17, 1972 to July 18, 1972
Start: 8:25 pin Stop: 1:00 am Duration: 4.33 hours
Volume treated: 10,753 cu m (2,841,000 gallons)
Average flow rate: 59,803 cu m/day (15-8 mgd)
Average transfer rate: 20,931 cu m/day (5-53 mgd) Percent return; 35
Average dry weather plant flow rate: 75,700 cu m/day (20 mgd)
_ Contact Tank _
HLSS: A, 984 mg/1 Contact time3: 16.51 min
BOD loading: 5,664 g/cu m/day (354 lb/day/1000 ft3)
F/Mb: 1.14 kg BOD/day/kg MLSS Air flow: 82.9 cu m/min (2962 cfm)
Air supply: 23.0 cu m/kg BOD applied (373 fWlb BOD applied)
_ Stab i 1 i za t ion Tank _
Stabilization timec: 3-0 days - S Reaeration time: 2.43 hours
Stabilization tank turnovers: 1.78 OUR: 3^ mg/l/hr
Oxygen supply: 340 kg/hr (750 Ib/hr)
_ Fi nal Clari f ier _
2
Surface overflow rate: 41.9 cu m/day/sq m (1026 gpd/ft )
Clarifier detention time3: 1.55 hours Clarifier turnovers: 2. 78
Clarifier solids loading: 281 ,088 g/day/sq m (57.6 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C16 (continued). OPERATING DATA FOR RUN NO. 16
Character istics
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total co 1 iform
Fecal col iform
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
Grit Contact
tank tank
6.9 6.8
5.2
600
121
231 4984
102 2651
88
11
88
18
3-29
83000
4200
Stabi 1 ization DWP
tank clarifier
6.75 7-20
Trace
568
162
15767 14
8050 3
12
4200 1
n
7
1.75
3800
80
Final
clarifier
7.15
Trace
474
135
11
3
15
3
18
16
1-75
1400
36
Percent
remova 1
21.0
95.2
97-1
82.9
72.7
79.5
11.1
45-9
98.3
99.1
-------
Table Cl?. DEFRAYING DATA FOR RUN NO. 1?
General
Date: July 19, 1972
Start: 3:52 pm Stop: 7-52 Duration: 4.01 hours
Volume treated: 10,114 cu m (2,672,000 gallons)
Average flow rate: 60,560 cu m/day (16.0 mgd)
Average transfer rate: 30,280 cu m/day (8.00 mgd) Percent return; 50
Average dry weather plant flow rate:
Contact Tank
MLSS: Contact time3: l4.67min
BOD loading: 24,928 g/cu m/day (1558 lb/day/1000 ft3)
- F/Mb: Air flow: 84.0 cu m/min (3000 cfm)
oo Air supply: 5.2 cu m/kg BOD applied (84 ftVlb BOD applied)
Stabi I ization^ Tank
Stabilization time0: 2.0 days - S Reaeration time: 1.77 hours
Stabilization tank turnovers: 2.26 OUR:
Oxygen supply: 340 kg/hr (750 Ib/hr)
Final Clarifier
Surface overflow rate: 42.4 cu m/day/sq m (1-39 gpd/ft )
Clarifier detention time3: 1.38 hours Clarifier turnovers: 2.90
Clarifier solids loading: 116,632 g/day/sq m (23.9 Ib/day/ft2)
a. Based on total flow.
b. Based on £1LSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C17 (continued). OPERATING DATA FOR RUN NO. 17
VD
Characteristics
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col i form
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
Grit Contact
tank tank
8.4 8.3
4.0
776
128
248 1840
1220
383
21
73
13.2
4.0
180000
130000
Stabilization DWP
tank clarifier
8.3 8.4
0.1
607
89
14633 20
8333 20
1078 68
27
4250 20
4.4
1.0
7900
3900
Final
clarifier
8.3
Trace
624
75
20
20
15
9
20
11 .0
1.3
9300
4600
Percent
remova I
19.6
41.4
91.9
96.0
57.1
72.6
16.7
67.5
94.8
96.4
-------
Table CIS. OPERATING DATA FOR RUM NO. 18
oo
o
General
Date: August 2, 1972
Start: 6:50 am Stop: 6:00 pm Duration: 11.04 hours
Volume treated: 28,607 cu m (7,558,000 gallons)
Average flow rate: 62,188 cu m/day ( 16.43 mgd)
Average transfer rate: 3','13 cu m/day (8.22 mgd) Percent return; 50
Average dry weather plant flow rate:
Contact Tank
MLSS: 5,150 mg/1 Contact time3: 14.29 min
BOD loading: 3,280 g/cu m/day (205 lb/day/1000 ft3)
F/Mb: 0.64 kg BOD/day/kg MLSS Air flow: 86.3 cu m/min (3081 cfm)
Air supply: 40.7 cu m/kg BOD applied (660 ft3/lb BOD applied)
Stabilization Tank
Stabilization timec: 10.0 days - S Reaeration time: 1.63 hours
Stabilization tank turnovers: 6.77 OUR: 72 mg/l/hr
Oxygen supply: 340 kg/hr (750 Ib/hr)
Final Clarifier
2
Surface overlfow rate: 43.5 cu m/day/sq m (1067 gpd/ft )
Clarifier detention time3: 1.34 hours Clarifier turnovers: 8.20
Clarifier solids loading: 335,256 g/day/sq m (68.7 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table CIS (continued). OPERATING DATA FOR RUM NO. 18
Character i st ics
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kj el da hi nitrogen as N
Total phosphorus as P
Tota 1 coliform
Fecal col i form
Uni ts
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
Grit
tank
7.20
3.20
556
219
202
88
49
H
62
16
8.2
1.9
230000
76000
Contact Stabilization DWP
tank tank clarifier
6.92 6.80 7.30
0.1
360
122
5150 14750 18
2900 8575 16
2200 12
2
3500 12
11
1.9
2.0
53000
7300
Final
clar if ier
7.50
Trace
442
168
35
19
19
3
22
15
4.1
1.8
26000
2400
Percent
removal
20.3
23.3
82.7
78.4
61.2
72.7
64.5
6.3
50.0
5.3
88.7
96.8
-------
Table C19- OPERATING DAGA FOR RUN NO. 19
General
Date: August 6, 1972 to August 7, 1972
Start: 11:52 pm Stop: 4:56 am Duration: 5-02 hours
Volume treated: 12,990 cu m (3,432,000 gallons)
Average flow rate: 62,112 cu m/day (16.41 mgd)
Average transfer rate: 13,622 cu m/day (4.92 mgd) Percent return;
Average dry weather plant flow rate:
Contact Tank
MLSS: 4,225 mg/l Contact time3: 16.51 min
BOD loading: 4,400 g/cu m/day (275 lb/day/1000 ft3)
F/Mb: 1.05 kg BOD/day/kg MLSS Air flow: 86.2 cu m/min (3077 cfm)
_ Air supply: 29.5 cu m/kg BOD applied (478 ftVlb BOD applied)
00
S ta b I 1 i za t i on Ta n k
Stabilization timec: 4.0 days - S Reaeration time: 2.68 hours
Stabilization tank turnovers: 1.87 OUR: 50mg/l/hr
Oxygen supply: 340 kg/hr (750 Ib/hr)
Fi nal Clari fi er
Surface overflow rate: 43-5 cu m/day/sq m (1066 gpd/ft^)
Clarifier detention time3: 1.55 hours Clarifier turnovers:
Clarifier solids loading: 238,144 g/day/sq m (48,8 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C19 (continued). OPERATING DATA FOR RUN NO. 19
Character ist ics
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
To ta 1 BO D
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal co 1 i form
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
Grit
tank
7.20
5.1
483
209
159
7k
66
7
75
9
10.2
2.9
83000
7200
Contact Stabilization DWP
tank tank clarifier
7.10 7-25 7.45
0.1
446
134
4225 13400 21
2250 7850 16
2350 9
1
4550 8
7
4.0
1-7
550
40
Fi nal
clar i f ier
7.40
Trace
428
152
18
5
Q
_/
1
14
10
5.4
1.8
2530
280
Percent
remova 1
11.4
27.3
88.7
93.2
86.4
85.7
81.3
47-1
37.9
96.9
96.1
-------
Table C20. OPERATING DATA FOR RUN NO. 20
General
Date: August 11, 1972
Start: 9=36 am Stop: 5:36 pm Duration: 8.00 hours
Volume treated: 23,391 cu m (6,180,0-0 gallons)
Average flow rate: 70,174 cu m/day (18.54 mgd)
Average transfer rate: 7,721 cu m/day (2.04 mgd) Percent return; 11
Average dry weather plant flow rate:
Contact Tank
00
MLSS: 2,100 mg/1 Contact time3: 17-11 min
BOD loading: 7,776 g/cu m/day (486 lb/day/1000 ft3)
F/P!b: 3-73 kg BOD/day/kg MLSS Air flov/: 97-3 cu m/min (3476 cfm)
Air supply: 19.2 cu m/kg BOD applied (312 ft3/lb BOD applied)
Stab i1izat ion Tank
Stabilization time
Stabi1i zat ion tank
Oxygen supply: 340
: 4.0 days - S
turnovers: 1.22
kg/hr (750 Ib/hr)
Reaeration time: 6.53 hours
OUR: 48 mg/l/hr
Fi nal Clari f ier
Surface overflow rate: 4g.l cu m/day/sq m (1204 gpd/ft )
Clarifier detention time : 1.61 hours Clarifier turnovers: 4.96
Clarifier solids loading: 114,192 g/day/sq m (23.4 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C20 (continued). OPERATING DATA FOR RUN NO. 20
CD
v_n
Characteristics
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
Grit Contact
tank tank
7.28 7-02
10
736
321
361* 2100
166 1175
103
2k
133
12
21.0
7.9
76000
8300
Stabilization DWP
tank clarifier
6.80 7.55
0.2
462
147
14575 12
8225
-------
Table C21 . OPERATING DATA FOR RUN NO. 21
General
Date: August 14, 1972
Start: 2:44 pm Stop: 10:24 pm Duration: 7-52 hours
Volume treated: 22,014 cu m (5,816,000 gallons)
Average flow rate: 69,644 cu m/day (18.4 mgd)
Average transfer rate: 6,964 cu m/day (1.84 mgd) Percent return; 10
Average dry weather plant flow rate:
Contact Tank
MLSS: 1,725 mg/1 Contact time3: 17-40 min .
BOD loading: 4,944 g/cu m/day (309 lb/day/1000 fr)
_ F/Mb: 2.88 kg BOD/day/kg MLSS Air flow: 96.6 cu m/min (3450 cfm)
oo Air supply: 29.8 cu m/kg BOD applied (483 ftVlb BOD applied)
Stab?1ization Tank
Stabilization time0: 3-0 days - S Reaeration time: 7-30 hours
Stabilization tank turnovers: 1.04 OUR: 67 mg/l/hr
Oxygen supply: 340 kg/hr (750 Ib/hr)
Final Clarifier
f\
Surface overflow rate: 48.8 cu m/day/sq m (1195 gpd/ft )
Clarifier detention time3: 1.64 hours Clarifier turnovers: 4.63
Clarifier solids loading: 92,232 g/day/sq m (18.9 Ib/day/ft )
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C21 (continued). OPERATING DATA FOR RUN NO. 21
CO
Character 1st ics
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/l
mg/1
mg/1
mg/l
#/ml
#/ml
Grit Contact
tank tank
7-75 7.30
3.3
763
280
288 1725
44 700
66
18
95
20
7.9
3. A
151000
8000
Stabi 1 ization DWP
tank clarifier
7-00 7.55
Trace
389
l*»8
18025 5
10875 <1
3150 13
2
6000 15
11
5.9
0.*»3
3200
100
Final
clarifier
7.52
Trace
280
116
AS
36
12
6
21
15
5.2
1.45
2kkQO
600
Percent
removal
63.3
58.6
83-3
18,2
81.8
66.7
77.9
25.0
34.2
57.4
83.8
92.5
-------
Table C22. OPERATING DATA FOR RUN NO. 22
oo
OO
General
Date: August 16, 1972
Start: 10:45 am Stop: 2:40 pm Duration: 3-8? hours
Volume treated: 10,795 cu m (2,852,000 gallons)
Average flow rate: 66,994 cu m/day (17-7 mgd)
Average transfer rate: 6,699 cu m/day (1.77 mgd) Percent return; 10
Average dry weather plant flow rate:
Contact Tank
MLSS: 1,725 mg/1 Contact time3: 12.14 min
BOD loading: 6,768 g/cu m/day (423 lb/day/1000 ft3)
F/Mb: 2.65 kg BOD/day/kg MLSS Air flow: 92.9 cu m/min (3319 cfm)
Air supply: 30.8 cu m/kg BOD applied (500 ftVlb BOD applied)
Stabilization Tank
Stabilization time0: 1.5 days - S Reaeration time: 7-32 hours
Stabilization tank turnovers: 0.53 OUR: 72 mg/l/hr
Oxygen supply: 340 kg/hr (750 Ib/hr)
Final Clarifier
n
Surface overflow rate: 46.9 cu m/day/sq m (1150 gpd/ft )
Clarifier detention time3: 1.70 hours Clarifier turnovers: 2.27
Clarifier solids loading: 88,816 g/day/sq m (18.2 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static conditon; C = continuous flow.
-------
Table C22 (continued). OPERATING DATA FOR RUN NO. 22
oo
Character 1st ics
pH
Settl eable sol ids
Total sol ids
Total volatile solids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
Grit Contact
tank tank
7.50 7.32
1.8
630
172
68 1725
k2 1163
63
17
50
21
9.7
3.7
460000
3600
Stabilization DWP
tank clarifier
6.92 7.75
0.1
618
184
19425 6
11675 3
3480 6
<1
5200 37
13
2.2
0.56
180
10
Fi nal
clar if ier
7.80
Trace
570
137
9
6
10
3
3^
14
3.9
1.50
800
33
Percent
removal
9.5
20.4
86.7
85.7
84.1
82.4
32.0
33.3
59.8
59.5
99.8
99.1
-------
Table C23. OPERATING DATA FOR RUN NO. 23
General
Date: November 3, 1972
Start: 8:55 am Stop: 2:55 pm Duration: 6.00 hours
Volume treated: 15, 7^9 cu m (^,161,000 gallons)
Average flow rate: 62,831 cu m/day ()6.6 mgd)
Average transfer rate: 25,132 cu m/day (6.6*» mgd) Percent return;
Average dry weather plant flow rate: 52,990 cu m/day (\k mgd)
_ Contact Tarik
MLSS: A, 075 mg/1 Contact time3: I5.15min
BOD loading: 5,872 g/cu m/day (367 lb/day/1000 ft3)
F/Mb: 1.45 kg BOD/day/kg MLSS Air flow: 87-1 cu m/m in (3112 cfm)
Air supply: 22.9 cu m/kg BOD applied (372 ftVlb BOD applied)
_ S ta b i 1 i za t i on Tank
Stabilization timec: 1.- days - S Reaeration time: 2.02 hours
Stabilization tank turnovers: 2.98 OUR: 50 mg/l/hr
Oxygen supply: 3^0 kg/hr (750 Ib/hr)
Final Clarif ier
2
Surface overlfow rate: M.O ru m/day/sq m (1078 gpd/ft )
Clarifier detention time3: 1.^3 hours Clartfier turnovers: ^.20
Clarif ier solids loading: 250, 3^ g/day/sq m (51.3 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C23 (continued). OPERATING DATA FOR RUN NO. 23
Characteristics
pH
Settleable sol ids
Total solids
Total volati le sol ids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
Grit Contact
tank tank
3.0
759
265
129 4075
78 2375
87
39
82
35
16.1
4.8
34000
1500
Stabilization DWP
tank clarifier
Trace
455
113
14150 13
8550 5
3850 10
10
5100 16
19
1.91
0.42
2300
38
Final
clarifier
Trace
548
159
45
29
34
11
34
20
8.85
2,63
20000
445
Percent
remova 1
27.8
40.0
65.1
62.8
60.9
71.8
58.5
42.9
45.0
45.2
41.2
70.3
-------
Table C2*». OPERATING DATA FOR RUN NO. 2k
General
Date: March 31, 1973
Start: 3:01 pm Stop: 6:02 pm Duration: 3.02 hours
Volume treated: 6,412 cu m (1,694,000 gallons)
Average flow rate: 50,946 cu m/day (13.46 mgd)
Average transfer rate: 19,417 cu m/day (5-13 mgd) Percent return; 38
Average dry weather plant flow rate:
Contact Tank
MLSS: 4,460 mg/1 Contact time3: 18.91 min
BOD loading: 7,248 g/cu m/day (453 lb/day/1000 ft3)
F/Mb: 1.63 kg BOD/day/kg MLSS Air flow: 42.0 cu m/min (1500 cfm)
M Air supply: 9.0 cu m/kg BOD applied (146 ft3/lb BOD applied)
S tab i 1 i za,t i on Tank
Stabilization timec: 4.50 days - C Reaeration time: 2.88 hours
Stabilization tank turnovers: 1.05 OUR: 30 mg/l/hr
Oxygen supply: 340 kg/hr (750 Ib/hr)
Final Clarifier
2
Surface overflow rate: 35.8 cu m/day/sq m (877 gpd/ft )
Clarifier detention time3: 1.78 hours Clarifier turnovers: 1.70
Clarifier solids loading: 219,600 g/day/sq m (45.0 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C2k (continued). OPERATING DATA FOR RUN NO. 2k
Character ist ics
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
COD"
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/m1
#/ml
mg/1
Grit Contact Stabilization DWP
tank tank tank clarifier
7.60 7.1*0 7-38 7-50
8.5
757
252
3*»7 M60 12630 27
150 2210 6600 6
132 266A 20
24
129 4400
27
16.3
5-72
45000
2600
407
Final
clari f ier
7-55
0.2
506
86
22
2
14
]
22
12
6.1
1.12
22000
4700
53
Percent
remova 1
97.6
33.1
66.0
93.6
98.8
89.4
95-8
82.9
45.5
62.6
80. 4
5K1
86.9
1973 only
-------
Table C25. OPERATING DATA FOR RUN NO. 25
General
Date: April 1, 1973
Start: 12:01 am Stop: 2:21 am Duration: 2.33 hours
Volume treated: 5,053 cu rn (1,335,000 gallons)
Average flow rate: 51,968 cu m/day (13-73 mgd)
Average transfer rate: 19,758 cu m/day (5-22 mgd) Percent return; 38
Average dry weather plant flow rate:
Contact Tank
MLSS: ^,550 mg/1 Contact time3: 18.58 min
BOD loading: 3,7^ g/cu m/day (23*t lb/day/1000 ft3)
F/Mb: 0.83 kg BOD/day/kg MLSS Air flow: 56.0 cu m/min (2000 cfm)
Air supply: 23.1 cu m/kg BOD applied (375 ft3/lb BOD applied)
Stabilization Tank
Stabilization timec: 1.0 days - S Reaeration time: 2.99 hours
Stabilization tank turnovers: 0.78 OUR: 30mg/l/hr
Oxygen supply: 3^0 kg/hr (750 Ib/hr)
Final Clarifier
Surface overflow rate: 36.A cu m/day/sq m (392 gpd/ft )
Clarifier detention time3: 1.75 hours Clarifier turnovers: 1.33
Clarifier sol ids loading: 227,896 g/day/sq m (46.7 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C25 (continued). OPERATING DATA FOR RUN NO. 25
Character ist ics
pH
Settl eable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
mg/1
Grit
tank
7.70
5
569
173
231
114
67
9
77
14
II. 1
3.73
21000
2200
221
Contact Stabilization DWP Final
tank tank clarifier clarifier
7.30 7.15 7.60 7.80
Trace
445
88
4550 11912 31 15
2525 6500 18 6
2650 14 9
2
4150 19
14
5.9
1.07
12700
2100
49
Percent
remova 1
21.7
49.1
93.5
94.9
86.5
77.7
75.3
46.8
71.3
39.5
4.5
77.8
-------
Table C26. OPERATING DATA FOR RUN NO. 26
General
Date: April 2, 1973
Start: 10:00 am Stop: 4:30 pm Duration: 6.50 hours
Volume treated: 14,239 cu m (3,762,000 gallons)
Average flow rate: 52,612 cu m/day (13-9 mgd)
Average transfer rate: 19,985 cu m/day (5-28 mgd) Percent return; 38
Average dry weather plant flow rate:
Contact Tank
MLSS: 3,700 mg/1 Contact time3: 18.36 min
BOD loading: 3,^0 g/cu m/day (215 lb/day/1000 ft3)
F/Mb: 0.94 kg BOD/day/kg MLSS Air flow: 56.0 cu m/min (2000 cfm)
Air supply: 25.1 cu m/kg BOD applied (407 ftVlb BOD applied)
S t ab i 1i za t i on Tank
Stabilization timec: 1.0 days - S Reaeration time: 2.89 hours
Stabilization tank turnovers: 2.25 OUR: 19mg/l/hr
Oxygen supply: 340 kg/hr (750 Ib/hr)
FinaJ Cla_r_ifie_r
2
Surface overflow rate: 36-8 cu m/day/sq m (903 gpd/ft )
Clarifier detention time3: 1.73 hours Clarifier turnovers: 3-76
Clarifier sol ids loading: 187,880 g/day/sq m (33.5 Ib/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow
-------
Table C26 (continued). OPERATING DATA FOR RUN NO. 26
Cha racter i sties
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/m1
mg/l
Grit Contact
tank tank
7.65 7-22
2.0
569
206
120 3700
79 2075
61
76
22
13.7
4.26
71700
4300
191
Stabilization DWP Final
tank clarifier clarifier
7.05 7.40 7.72
Trace
465
101
12087 79 17
6650 42 13
1800 23 4
4250 16
12
6.6
1.34
23000
380
44
Percent
removal
18.2
51.1
85.8
83.6
93- 4
78.9
45.4
51.8
68.5
67.9
91.2
76.9
-------
Table C27- OPERATING DATA FOR RUM NO. 27
General
Date: Apr! 1 4, 1973
Start: 10:07 am Stop: 2:37 pm Duration: 4.50 hours
Volume treated: 7,116 cu m (1,880,000 gallons)
Average flow rate: 37,850 cu m/day (10.0 mgd)
Average transfer rate: 37,850 cu m/day (10.00 mgd) Percent return; 100
Average dry weather plant flow rate:
_ Contact Tank _
MLSS: 4,770 mg/1 Contact time3: 17.61 min
BOD loading: 2,528 g/cu m/day (158 lb/day/1000 ft3)
F/Hb: 0.53 kg BOD/day/kg MLSS" Air flow: 56.0 cu m/min (2000 cfm)
Air supply: }k,k cu m/kg BOD applied (557 ft3/lb BOD applied)
_ Stabilization Tank _
Stabilization time0: 2.0 days - S Reaeration time: 1.34 hours
Stabilization tank turnovers: 3.36 OUR: 13 mg/l/hr
Oxygen supply: 3^0 kg/hr (750 Ib/hr)
_ Final Cjarifier _
Surface overflow rate: 26.5 cu m/day/sq m (650 gpd/ft )
Clarifier detention time3: 1.66 hours Clarifier turnovers: 2.71
Clarifier solids loading: 252,296 g/day/sq m (51.7 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C27 (continued). OPERATING DATA FOR RUN NO. 27
Characteristics
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
mg/1
Grit Contact
tank tank
7.87 7.55
1.8
579
225
145 4770
36 2770
62
32
75
30
12.5
3-15
720
135
183
Stabilization DWP Final
tank clarifier clarifier
7.40 7.55 7.65
Trace
526
158
9150 38 25
5140 19 17
2150 14 9
3
3850 19
11
7.3
1.04
510
56
48
Percent
removal
9.1
29.8
82.7
80.2
85.4
90.6
74.6
63.3
41.6
66.9
29.2
58.6
73.7
-------
Table C28. OPERATING DATA FOR RUN NO. 28
o
o
General
Date: April 11, 1973
Start: 8:10 am Stop: 11:10 am Duration: 3-00 hours
Volume treated: 8,9^0 cu m (2,362,000 gallons)
Average flow rate: 71,^99 cu m/day (18.89 mgd)
Average transfer rate: k,\Gb cu m/day (1.1 mgd) Percent return; 6
Average dry weather plant flow rate:
Contact Tank
MLSS: 1,500 mg/1 Contact time3: 17.62 min
BOD loading: 6,4^8 g/cu m/day (403 lb/day/1000 ft3)
F/Mb: 4.33 kg BOD/day/kg MLSS Air flow: 56.0 cu m/min (2.000 cfm)
Air supply: 13-1* cu m/kg BOD applied (218 ftVlb BOD applied)
StabiIizat ion
Stabilization timec: 7.0 days - S Reaeration time: 12.60 hours
Stabilization tank turnovers: 0.2^ OUR: I4mg/1/hr
Oxygen supply: 3^0 kg/hr (750 Ib/hr)
Final Clarifier
Surface overflow rate: 50.1 cu m/day/sq m (1,227
Clarifier detention time3: 1.66 hours Clarifier turnovers: 1.81
Clarifier solids loading: 79,056 g/day/sq m (16.2 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow
-------
Table C28 (continued). OPERATING DATA FOR RUN NO. 28
Characteristics
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col i form
Fecal col iform
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/l
mg/1
mg/1
mg/1
mg/1
mg/1
mg/ I
ti/m 1
/7ml
mg/1
Grit
tank
.85
9-0
8^8
335
318
211
8A
22
127
27
20.3
5-7
Woo
1000
305
Contact Stabilization DWP Final
tank tank clarifier clarifier
7.75 7.50 7.75
0.3
599
210
1500 10650 23 69
930 5975 16 ^
2150 7 27
9
3550 50
18
10.5
2.5
635
100
82
Percent
removal
96.6
29.3
37-3
78.3 .
76.7
67.8
59-0
60.6
33.3
W.2
56.1
85-5
90.0
73.1
-------
Table C29. OPERATING DATA FOR RUN NO. 29
General
Date: April 13, 1973
Start: 10:20 am Stop: 2:50 pm Duration: 4.50 hours
Volume treated: 12,869 cu m (3,400,000 gallons)
Average flow rate: 68,622 cu m/day (18.13 mgd)
Average transfer rate: 29,334 cu m/day (7-75 mgd) Percent return; 40
Average dry weather plant flow rate:
Contact Tank
MLSS: 3,140 mg/1 Contact time3: 9.31 min
BOD loading: 13,120 g/cu m/day (820 lb/day/100 ft3)
F/Mb: 4.12 kg BOD/day/kg MLSS Air flow: 56.0 cu m/min (2,000 cfm)
Air supply: 10.1 cu m/kg BOD applied (163 ft3/lb BOD applied)
Stabi1 Izati on tank
Stabilization time0: 2.0 days - S Reaeration time: 2.10 hours
Stabilization tank turnovers: 2.14 OUR: 39 mg/l/hr
Oxygen supply: 340 kg/hr (750 Ib/hr)
Fi nal Clari f ier
Surface overflow rate: 48.0 cu m/day sq m (1,177 gpd/ft2)
Clarifier detention time3: 1.31 hours Clarifier turnovers: 3.44
Clarifier solids loading: 210,816 g/day/sq m (43.2 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C2° (continued). OPERATING DATA FOR RUN NO.
M
O
Character! sties
pH
Sett leable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col i form
Fecal co 1 iform
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
fi'/ml
.7 /ml
mg/1
Grit Contact
tank tank
7.82 7.45
4.2
832
237
224 3140
97 1570
117
44
146
38
12.6
3-95
225
Stabilization DWP Final
tank clarifier clarifier
7.25 7-75
Trace
608
140
10800 13 13
5400 5 4
2500 6 10
4
3600 17
12
7.5
1.16
2250
750
34
Percent
remova 1
26.9
40.9
94.1
95.8
91 .4
90.9
88.3
68.4
40.4
70.6
88.3
64.2
84.8
-------
Table C30. OPERATING DATA FOR RUN NO. 30
General
Date: April 16, 1973
Start: 9:05 am Stop: 3:05 pm Duration: 6.00 hours
Volume treated: 17,941 cu m (4,740,000 gallons)
Average flow rate: 71,764 cu m/day (18.96 mgd)
Average transfer rate: 14,345 cu m/day (3.79 mgd) Percent return; 20
Average dry weather plant flow rate:
Contact Tank
MLSS: 1,280 mg/I Contact time3: 10.39 min ,
BOD loading: 10,6o8 g/cu m/day (663 lb/day/1000 ft )
F/Mb: 8.31 kg BOD/day/kg MLSS Air flow: 5&.0 cu m/min (2,000 cfm)
Air supply: 12.2 cu m/kg BOD applied (198 ft^/lb BOD applied)
StabiIization Tank
Stabilization timec: 3.0 days - S Reaeration time: 4.11 hours
Stabilization tank turnovers: 1.45 OUR: 46 mg/l/hr
Oxygen supply: 340 kg/hr (750 Ib/hr)
Final Clarifier
f)
Surface overflow rate: 50.2 cu m/day/sq m (1,231 gpd/ft )
Clarifier detention time3: 1.46 hours Clarifier turnovers: 4.11
Clarifier solids loading: 77,104 g/day/sq m (15.8 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C30 (continued). OPERATING DATA FOR RUN NO. 30
r-o
O
Character i st ics
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sal ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col if orm
Fecal col if orm
COD
Units
ml/1
mg/1
mq/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
mg/1
Grit Contact Stabilization DWP
tank tank tank clarifier
7.66 7.35 7.35
4.0
685
220
244 1280 13725 35
227 1140 8525 35
92 3300 12
33
296 3950
33
13.5
4.17
5400
580
690
F i na 1
clarifier
7.80
0.1
550
151
67
67
25
7
31
14
9-3
1.98
6000
2600
71
Percent
remova 1
97.5
19.7
31.4
72.5
70.5
72.8
78.8
89.5
57.6
31.1
50.3
89.7
-------
Table C31 . OPERATING DATA FOR RUN NO. 31
General
Date: April 29, 1973 to April 30, 1973
Start: 7-35 pm Stop: 1:35 am Duration: 6.00 hours
Volume treated: 9,133 cu m (2,^13,000 gallons)
Average flow rate: 36,525 cu m/day (9-65 mgd)
Average transfer rate: 36,525 cu m/day (9-65 mgd) Percent return; 100
Average dry weather plant flow rate: 75,700 cu m/day (20 mgd)
Contact Tank
MLSS; 5,550 mg/1 Contact time3: 12,2^ min
BOD loading: 3,088 g/cu m/day (193 lb/day/1000 ft3)
F/Mb: 0.56 kg BOD/day kg MLSS Air flow: 56.0 cu m/min
o Air supply: M.6 cu m/kg BOD applied (675 ft^/lb BOD applied)
CTV
Stabi1ization Tank
Stabilization time0: 3-0 days - S
Stabilization tank turnovers: ^.32
Oxygen supply: 3*»0 kg/hr (750 Ib/hr)
Reaeration time:
OUR:
1 .39 hours
Final Clarifier
n
Surface overflow rate: 25-6 cu m/day/sq m (627 gpd/ft )
Clarifier detention time3: 1.72 hours Clarifier turnovers: 3.^9
Clarifier solids loading: 283,0^0 g/day/sq m (53.0 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C31 (continued). OPE RAT IMG DATA FOR RUN MO. 31
Character i s t ics
pH
Sett leable sol ids
Total sol ids
Total volat i le sol ids
Suspended solids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as \\
Total phosphorus as P
Total col i form
Fecal col i form
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
mg/1
Gr i t Contact
tank tank
7.70 7.20
2.5
45)4
103
115 5550
56 2750
53
13
62
18
14.5
2.4
7800
1630
133
Stabilization DWP Final
tank clarifier clarifier
7.20 7.20 7.70
Trace
514
125
11400 35 27
5780 15 13
2500 14 12
5
3950 33
15
9
0.46
1870
490
48
Percent
remova 1
76.5
76.7
77.3
61.5
46.7
16.6
37.9
80.8
76.0
70.8
63.9
-------
Table C32. OPERATING DATA FOR RUN NO. 32
General
Date: May 1, 1973
Start: 10:00 am Stop: 2:00 pm Duration: 4.00 hours
Volume treated: 11,310 cu m (2,988,000 gallons)
Average flow rate: 67,865 cu m/day (17.93 mgd)
Average transfer rate: 33,914 cu m/day (8.96 mgd) Percent return; 50
Average dry weather plant flow rate: 75,700 cu m/day (20 mgd)
Contact Tank
MLSS: 4,750 mg/1 Contact time3: I3.10min
BOD loading: 4,016 g/cu m/day (251 lb/day/1000 ft3)
M F/Mb: 1.27 kg BOD/day kg MLSS Air flow: 56.0 cu m/min (2,000 cfm)
g, Air supply: 21.6 cu m/kg BOD applied (350 ft3/lb BOD applied)
Stabilization Tank
Stabilization timec: 0.0 days Reaeration time: 1.46 hours
Stabilization tank turnovers: 2.75 OUR:
Oxygen supply: 340 kg/hr (750 Ib/hr)
Final Clarifier
Surface overflow rate: 47-5 cu m/day/sq m (1,165 gpd/ft )
Clarifier detention time3: 1.23 hours Clarifier turnovers: 3.24
Clarifier solids loaindg: 337,696 g/day/sq m (79.2 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C32 (continued). OPERATING DATA FOR RUN NO. 32
Characteristics
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col i form
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
mg/1
Grit
tank
7.75
1.5
549
i4o
32
52
55
30
^3
7.75
1.92
1480
440
130
Contact Stabilization DW Final
tank tank clarifier clarifier
7.20 7.10 7.80
Trace
430
96
4750 12800 24 17
2450 6550 11 8
3050 8 7
<1
3900 20
8
3.65
0.78
<14
<10
32
Percent
remoya I
21.6
31.4
81.5
84.6
87.2
>96.6
53.4
68.0
52.9
59.3
>99.0
>97.7
75.3
-------
Table C33- OPERATING DATA FOR RUN NO. 33
General
Date: May 3, 1973
Start: 10:00 am Stop: 1:35 pm Duration: 3-57 hours
Volume treated: 10,473 cu m (2,767,000 gallons)
Average flow rate: 70,401 cu m/day (18.60 mgd)
Average transfer rate: 35,200 cu m/day (9,30 mgd) Percent return; 50
Average dry weather plant flow rate: 75,700 cu m/day (20 mgd)
Contact Tank
MLSS: 4,930 mg/1 Contact time3: 12.62 min
BOD loading: 5,744 g/cu m/day (359 lb/day/1000 ft3)
F/Mb: 1.17 kg BOD/day/kg MLSS Air flow: 56.0 cu m/min (2000 cfm)
Air supply: 15.0 cu m/kg BOD applied (244 ft3/lb BOD applied)
Stabi1ization Tank
Stabilization time : 0.0 days Reaeration time: 1.40 hours
Stabilization tank turnovers: 2.54 OUR:
Oxygen supply: 340 kg/hr (750 Ib/hr)
Final Clarifier
Surface overflow rate: 49.3 cu m/day/sq m (1,208 gpd/ft2)
Clarifier detention time3: 1.19 hours Clarifier turnovers: 3.00
Clarifier solids loading: 363,560 g/day/sq m (74.5 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C33 (continued). OPERATING DATA FOR RUN NO. 33
Character! sties
pH
Settleable sol ids
Total solids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kj el da hi nitrogen as N
Total phosphorus as P
Total col i form
Feca 1 col i form
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/m1
#/m1
mg/1
Grit Contact
tank tank
7.85 7.*»8
1.5
651
195
92 A930
50 2300
76
43
56
34
10.3
2.8
7500
4700
183
Stabilization DWP Final
tank clarifier clarifier
7.40 7.80
Trace
631
168
14600 33 17
7180 9 7
3393 11 11
3
4250 19
13
7.4
1 .08
1500
510
40
Percent
removal
3.0
13.8
81.5
86.0
85.5
93.0
66.0
61.7
28.1
61.4
56.0
89.1
78.1
-------
Table C3'(. OPERATING DATA FOR RUN NO. 3'4
Date: May 7, 1973
Start: 1:30 pni Stop: 5:30 pm Duration: 4.00 hours
Volume treated: 11,900 cu m (3,144,000 gallons)
Average flow rate: 71,335 cu m/day (18.86 mgd)
Average transfer rate: 3,558 cu m/day (0-94 mgd) Percent return; 5
Average dry weather plant flow rate: 83,270 cu m/day (22 mgd)
Contact Tank
MLSS: 1,350 mg/1 Contact time3; 11.93 min
BOD loading: 8,576 g/cu m/day (536 lb/day/1000 ft3)
F/Mb: 6.39 kg BOD/day/kg MLSS Air flow: 56.0 cu m/min (2,000 cfm)
Air supply: 15-0 cu m/kg BOD applied (244 ft3/lb BOD applied)
Stabilization Tank
Stabi 1 i zat ion
Stab! 1 i za t ion
Oxygen supply
timec: 3-0 days - S Reaeration time:
tank turnovers: 0.38 OUR:
: 284 kg/hr (625 lb/hr)
Final Clarifier
10.65 hours
Surface overflow rate: 50.0 cu m/day/sq m (1,225 gpd/ft )
Clarifier detention time3: 1.67 hours Clarifier turnovers: 2.39
Clarifier solids loading: 70,760 g/day/sq m (14.5 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C34 (continued). OPERATING DATA FOR RUN NO. 34
M
Character ist ics
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Tota 1 col i form
Fecal col i form
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
mg/o
Grit Contact
tank tank
7.45 7.10
3.3
649
188
131 1350
62 600
75
30
72
26
10.5
3-99
44000
4000
206
Stabilization DWP Final
tank clarifier clarifier
7.40
Trace
581
134
3725 27 42
1825 12 22
700 10 25
6
1050 27
15
8.4
2.08
3350
1500
67
Percent
remova 1
10.5
28.7
67.9
64.5
66.6
80.0
62.5
42.3
20.0
47.8
92.3
62.5
67.4
-------
Table C35- OPERATING DATA FOR RUM NO. 35
General
Date: May 25, 1973
Start: 5:03 am Stop: 8:12 am Duration: 3.15 hours
Volume treated: 8,251 cu m (2,180,000 gallons)
Average flow rate: 62,869 cu m/day (16.61 mgd)
Average transfer rate: 18,849 cu m/day (A.98 mgd) Percent return; 30
Average dry weather plant flow rate: 75,700 cu m/day (20 mgd)
Contact Tank
MLSS: 2,670 mg/1 Contact time3: 10.94 min
BOD loading: 25,792 g/cu m/day (1,612 lb/day/1000 ft3)
F/Mb: 9-71 kg BOD/day/kg MLSS Air flow: 52.5 cu m/min (1,875 cfm)
Air supply: 4 .1 cu m/kg BOD applied (76 ftVlb BOD applied)
Stabi1i zat ion Tank
Stabilization time : 3-14 days - C Reaeration time: 2.42 hours
Stabilization tank turnovers: 1.30 OUR: 50 mg/l/hr
Oxygen supply: 284 kg/hr (625 lb/hr)
Final Clarifier
Surface overflow rate: 44.0 cu m/day/sq m (1,079 gpd/ft2)
Clarifier detention time : 1.54 hours Clarifier turnovers: 2.05
Clarifier solids loading: 152,256 g/day/sq m (31.2 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C35 (continued). OPERATING DATA FOR RUN NO. 35
Character ist ics
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col i form
Fecal col iform
COD
Units
m)/l
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/l
mg/1
mg/1
///ml
,f/ml
mg/1
Grit Contact
tank tank
7.70 7.30
12.0
864
352
588 2670
274 1420
256
22
123
20
14.0
5.30
450
340
Stabilization DWP Final
tank clarifier clarifier
7.10 7-40 7.60
Trace
416
98
11000 33 22
3400 21 16
3400 20 21
14
3100 25
18
5.85
0.88
210
59
Percent
remova 1
51.8
72.1
96.2
94.1
91.7
36.3
80.6
10.0
58.2
83.3
53.3
82.6
-------
Table C36. OPERATING DATA FOR RUN NO. 36
General
Date: May 27, 1973
Start: 3:25 pm Stop: 9:25 pm Duration: 6.00 hours
Volume treated: 17,581 cu m (4,645,000 gallons)
Average flow rate: 70,325 cu m/day (18.58 mgd
Average transfer rate: 21,082 cu m/day (5-57 mgd) Percent return; 30
Average dry weather plnat flow rate: 94,625 cu m/day (25 mgd)
Contact Tank
MLSS: 3,210 mg/1 Contact timea: 14.58 min
BOD loading: 4,832 g/cu m/day (302 lb/day/1000 ft3)
F/Mb: 1.52 kg BOD/day/kg MLSS Air flow: 52.5 cu m/min (1,875 cfm)
Air supply: 16.8 cu m/kg BOD applied (272 ft^/lb BOD applied)
Stabilization Tank
Stabilization timec: 1.0 days - S Reaeration time: 1.62 hours
Stabilization tank turnovers: 3-70 OUR: 39 mg/l/hr
Oxygen supply: 284 kg/hr (625 Ib/hr)
Final Clarifier
Surface overflow rate: 49.2 cu m/day/sq m (1,207 gpd/ft2)
Clarifier detention time3: 1.37 hours Clarifier turnovers: 4.37
Clarifier solids loading: 204,960 g/day/sq m (42.0 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C » continuous flow.
-------
Table C3& (continued). OPERATING DATA FOR RUN NO. 36
N>
—I
Character \ st i cs
pH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as H
Total phosphorus as P
Total col iform
Fecal col iform
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
mg/l
Grit Contact Stabilization DWP
tank tank tank clar!fier
7-60 7.35 7.25
10.0
587
234
354 3210 12100 32
170 1640 6330 22
64 1700 U
5
98 3200
2k
20.6
2.86
4000
140
237
Final
clar i f ier
7.70
Trace
475
129
36
21
12
4
26
17
11.1
1.44
140
<10
65
Percent
removal
19.0
44.8
89.8
87.6
81.2
20.0
73.4
29.1
46.1
49.6
96.5
>92.8
72.5
-------
Table C37. OPERATING DATA FOR RUN NO. 37
NJ
CO
General
Date: June 4, 1973
Start: 4:32 am Stop: 7:04 am Duration: 2.50 hours
Volume treated: 7,305 cu m (1,930,000 gallons)
Average flow rate: 70,136 cu m/day (18.53 mgd)
Average transfer rate: 24,565 cu m/day (6.49 mgd) Percent return; 35
Average dry weather plant flow rate: 64,345 cu m/day (17 mgd)
Contact Tank
MLSS: 4,020 mg/1 Contact time3: 14.08 min
BOD loading: 6,864 g/cu m/day (429 lb/day/1000 ft3)
F/Mb: 1.70 kg BOD/day/kg MLSS Air flow: 52.5 cu m/min (1,875 cfm)
Air supply: 11.8 cu m/kg BOD applied (192 ft3/lb BOD applied)
Stabilization Tank
Stabilization timec: 2.76 days - C
Stabilization tank turnovers: 1.70
Oxygen supply: 284 kg/hr (625 lb/hr)
Reaeration time:
OUR:
1 .47 hours
Final Clarifier
Surface overflow rate: 49.1 cu m/day/sq m (1,204 gpd/ft2)
Clarifier detention time8: 1.33 hours Clarifier turnovers: 1.89
Clarifier solids loading: 265,960 g/day/sq m (54.5 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C37 (continued). OPERATING DATA FOR RUN NO. 37
Character ist ics
pit
Settleable sol ids
Total sol ids
Total vola ti le sol ids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOO
Total organic carbon
Dissolved organic carbon
Kj el da hi nitrogen as N
Total phosphorus as P
Total col i form
Fecal col iform
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
mg/1
Grit Contact Stabilization DWP
tank tank tank clarifier
7-50 7.10 7.25
5.0
652
250
340 4020 11750 25
162 2070 6500 11
91 2080 9
11
109 3300
30
10.4
2.74
96700
8200
309
Fi na 1
cl ar if ier
7.60
Trace
466
141
26
9
17
6
24
12
8.6
1.61
12200
1500
57
Percent
remova 1
28.5
43.6
92.6
94.4
31.3
45.4
78.0
60.0
17.3
41.2
87.4
81.7
81.6
-------
Table C38. OPERATING DATA FOR RUN NO. 38
General
Date: June 4, 1973
Start: 10:22 am Stop: 3:11 pm Duration: 4.80 hours
Volume treated: 13,97** cu m (3,692,000 gallons)
Average flow rate: 69,87! cu m/day (18.46 mgd)
Average transfer rate: 29,334 cu m/day (7-75 mgd) Percent return; k2
Average dry weather plant flow rate: 56,775 cu m/day (15 mgd)
Contact Tank
MLSS: 3,800 mg/1 Contact time3: 13-44 min
BOD loading: 16,064 g/cu m/day (1,00k lb/day/1000 ft3)
M F/Mb: 4.26 kg BOD/day/kg HLSS Air flow: 52-5 cu m/min (1,875 cfm)
o Air supply: 5.1 cu m/kg BOD applied (82 ft^/lb BOD applied)
Stabilization Tank
Stabilization time0: 0.0 Reaeration time: 1-55 hours
Stabilization tank turnovers: 3-09 OUR: 36 mg/l/hr
Oxygen supply: 284 kg/hr (625 Ib/hr)
F i na 1 Clarifier
Surface overflow rate: 48.9 cu m/day/sq m (1,199 gpd/ft2)
Clarifier detention time3: 1.26 hours Clarifier turnovers: 3.79
Clarifier solids loading: 263,520 g/day/sq m (54.0 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C38 (continued). OPERATING DATA FOR RUN NO. 38
Character 1st ics
pit
Settleable sol ids
Tota 1 sol ids
Total volat i le sol ids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kj el da hi nitrogen as N
Total phosphorus as P
Tota 1 col i form
Feca 1 col iform
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
F/ml
8M
mg/1
Grit
tank
7.60
4
632
242
192
135
214
47
115
42
16.8
6.39
24500
1350
292
Contact Stabilization DWP Final
tank tank clarifier clarifier
7.30 7.20 7.65
Trace
441
131
3300 10500 15 21
1550 5630 9 10
2373 7 16
5
3000 22
17
10.6
3.22
8400
2250
54
Percent
remova 1
30.2
45.9
89.1
92.6
92.5
89-4
80.9
59.5
36.9
49.6
65.7
81.5
-------
Table C39- OPERATING DATA FOR RUN NO. 39
General
Date: June 6, 1973
Start: 12:45 am Stop: 3:05 pm Duration: 2.33 hours
Volume treated: 5,371 cu m (1,419,000 gallons)
Average flow rate: 55,337 cu m/day (14.62 mgd)
Average transfer rate: 26,571 cu m/day (7-02 mgd) Percent return; 48
Average dry weather plant flow rate: 64,345 cu m/day (17 mgd)
Contact Tank
MLSS: 4,810 mg/1 Contact time3: 16.28 min
BOD loading: 6,368 g/cu m/day (398 lb/day/1000 ft3)
F/Mb: 1.33 kg BOD/day/kg MLSS Air flow: 52.5 cu m/min (1,875 cfm)
Air supply: 12.8 cu m/kg BOD applied (207 ft3/lb BOD applied)
Stabi1ization Tank
Stabilization time0*: 0.0 days Reaeration time: 1.14 hours
Stabilization tank turnovers: 2.04 OUR: 68 mg/l/hr
Oxygen supply: 284 kg/hr (625 Ib/hr)
Final Clarifier
Surface overflow rate: 38.8 cu m/day/sq m (950 gpd/ft2)
Clarifier detention time3: 1.53 hours Clarifier turnovers: 1.52
Clarifier solids loading: 275,232 g/day/sq m (56.4 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C39 (continued). OPERATING DATA FOR RUN NO. 39
Character ist ics
pH
Settleable sol ids
Total sol ids
Total volati le sol ids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col i form
Fecal col iform
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
mg/1
Grit
tank
7.55
3.0
637
191
148
107
107
65
103
51
13.2
6.0
30000
3600
293
Contact Stabilization DWP Final
tank tank clarifier clarifier
7-25 7.00 7-60
Trace
486
105
4810 21900 13 22
2870 14130 5 16
4887 7 15
4
7350 24
15
9.6
3.63
13000
2100
44
Percent
remova 1
23.7
45.0
85.1
85.0
86.0
93.8
76.7
70.6
27.3
39.5
56.7
41.7
85.0
-------
Table CAO. OPERATING DATA FOR RUN MO.
Genera 1
Date: June 16, 1973
Start: 3:l*8 pm Stop: 11:28 pm Duration: 6.79 hours
Volume treated: 1^,8^*9 cu m (3,923,000 gallons)
Average flow rate: 53, ^98 cu m/day (13.87 mgd)
Average transfer rate: 39,36^ cu m/day (10.^0 mgd) Percent return; 75
Average dry weather plant flow rate: 83,270 cu m/day (22 mgd)
_ Contact Tank _
MLSS: ^,780 mg/1 Contact time3: Hi. 51 min
BOD loading: 8,016 g/cu m/day (501 lb/day/1000 ft3)
F/Mb: 1.68 kg BOD/day/kg MLSS Air flow: 52.5 cu m/min (1,875 cfm)
Air supply: 10. 1 cu m/kg BOD applied (16A ft3/lb BOD applied)
_ Stabi 1 ization Tank _
Stabilization timec: 2.50 days - C Reaeration time: 0.96 hours
Stabilization tank turnovers: 7.0*t OUR:
Oxygen supply: 227 kg/hr (500 Ib/hr)
_ Final Clarifier _
Surface overflow rate: 36.8 cu m/day/sq m (901 gpd/ft^)
Clarifier detention time : 1.37 hours Clarifier turnovers: *».97
Clarifier solids loading: 306,952 g/day/sq m (62.9 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C - continuous flow.
-------
Table C40 (continued). OPERATING DATA FOR RUN NO. 40
Characteristics
pH
Settleable sol ids
Total sol ids
Total vol at i le sol ids
Suspended sol i ds
Suspended volatile solids
Total BOO
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen. as U
Total phosphorus as P
Total col i form
Feca 1 col iform
COD
Uni ts
ml/1
mg/1
mg/1
mg/1
mg/1
mg/l
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
mg/1
Grit Contact
tank tank
7-35 7.10
6.5
812
328
445 4780
274 2870
142
29
199
30
15.4
3-07
90000
1280
390
Stabilization DWP Final
tank clarifier clarifier
7-05 7-60
Trace
502
158
11518 596 16
7336 456 11
2400 145 19
8.0
4050 30
5
7.6
1.03
29500
185
76
Percent
remova 1
38.1
51.8
96.4
95.9
86.6
72.4
84.9
83.3
50.6
66.4
67.2
85-5
80/5
-------
Table CM. OPERATING DATA FOR RUN NO.
ro
C-.
General
Date: June 16, 1973 to June 17, 1973
Start: 12:15 pm Stop: 12:15 am Duration: 12.00 hours
Volume treated: 27,646 cu m (7,304,000 gallons)
Average flow rate: 55,299 cu m/day (14.61 mgd)
Average transfer rate: 27,630 cu m/day (7-30 mgd) Percent return; 50
Average dry weather plant flow rate: 90,840 cu m/day (24 mgd)
Contact Tank
MLSS: 3,353 mg/1 Contact time3: 16.07 min
BOD loading: 3,504 g/cu m/day (219 lb/day/1000 ft3)
F/Mb: 1.05 kg BOD/day/kg MLSS Air flow: 52.5 cu m/min (1,875 cfm)
Air supply: 23.2 cu m/kg BOD applied (376 ftvlb BOD applied)
Stabilization Tank
Stabilization time0: 1.0 days - S Reaeration time: 1.58 hours
Stabilization tank turnovers: 7.59 OUR: 59mg/l/hr
Oxygen supply: 227 kg/hr (500 Ib/hr)
Final Clarifier
f\
Surface overflow rate: 38.7 cu m/day/sq m (949 gpd/ft )
Clarifier detentiom time3: 1.51 hours Clarifier turnovers: 7-93
Clarifier solids loading: 194,224 g/day/sq m (39.8 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C4l (continued). OPERATING DATA FOR RUN NO. 41
Character ist ics
pll
Settleable sol ids
Total sol ids
Total volat i le sol ids
Suspended sol ids
N> Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col i form
Fecal col iform
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/l
mg/1
mg/1
mg/1
mg/1
,Vml
#/nl
mg/1
Grit Contact Stabilization
tank tank tank
7.55 7-15 7.10
3.5
604
233
156 3353 11510
123 1342 7190
59 2750
18
83 4100
22
10.3
37600
5600
211
DWP Final
clarifier clarifier
7.75
Trace
443
124
551 15
456 14
59 11
8
27
17
5.4
0.95-
4600
1300
46
Percent
remova 1
26.6
46.7
90.3
88.6
81.3
55.5
67.4
22.7
47.5
82.9
87.7
76.7
78.1
-------
Table C42. OPERATING DATA FOR RUN NO. 42
General
Date: July 3, 1973
Start: 12:39 pm Stop: 3:38 pm Duration: 2.97 hours
Volume treated: 7,831 cu m (2,069,000 gallons)
Average flow rate: 63,285 cu m/day (16.72 mgd)
Average transfer rate: 31 ,643 cu m/day (8.36 mgd) Percent return; 50
Average dry weather plant flow rate
Contact Tank
MLSS: 3,690 mg/1 Contact time3: 9.42 min
BOD loading: 11,456 g/cu m/day (816 lb/day/1000 ft3)
F/Mb: 2.09 kg BOD/day/kg MLSS Air flow: 52.5 cu m/min (1,875 cfm)
Air supply: 10.5 cu m/kg BOD applied (171 ft3/lb BOD applied)
Stabilization Tank
Stabilization time0: 2.90 days - C
Stabilization tank turnovers: 2.75
Oxygen supply: 227 kg/hr (500 Ib/hr)
Reaeration time:
OUR:
1 .08 hours
Final Clarifier
Surface overflow rate: 44.3 cu m/day/sq m (1,086 gpd/ft*)
Clarifier detentiom time3: 1.32 hours Clarifier turnovers: 2.25
Clarifier solids loading: 244,488 g/day/sq m (50.1 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow
-------
Table C42 (continued). OPERATING DATA FOR RUN NO. 42
ISJ
N3
VD
Character ist ics
pH
Sett leable sol i ds
Tota 1 sol ids
Total volat i le sol ids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kj el da hi nitrogen as N
Total phosphorus as P
Tota 1 col i form
Fecal col i form
COD
Uni ts
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
mg/1
Grit Contact
tank tank
7-35
5.1
576
240
291 3690
163 1950
113
46
56
36
67.3
7-76
100000
28000
416
Stabilization DWP Final
tank clarifier clarifier
6.90 7.15 7.40
1.1
495
198
10500 274
5820 176
2200 39
16
2750 36
21
39.3
4.21
8100
610
97
Percent
remova 1
78.4
14.1
17.5
5.8
65.5
65.2
35.7
41.7
41.6
45.7
91.9
97-8
76.7
-------
Table C43. OPERATING DATA FOR RUN NO. 43
r-o
VjO
o
Date: July 20, 1973
Start: 4:48 pm Stop: 10:08 pm Duration:
Volume treated: 15,469 cu m (4,087,000 gallons)
Average flow rate: 69.379 cu m/day (18.33 mgd)
5-35 hours
Average transfer rate: 27,744 cu m/day (7-33 mgd) Percent return; 40
Average dry weather plant flow rate: 71,915 cu m/day (19 mgd)
Contact Tank
MLSS: 2,670 mg/1 Contact time3: 13.72min
BOD loading: 13,872 g/cu m/day (867 lb/day/1000 ft3)
F/Mb: 5.23 kg BOD/day/kg MLSS Air flow: 52.5 cu m/min (1,875 cfm)
Air supply: 5-9 cu m/kg BOD applied (95 ft3/lb BOD applied)
Stabi1izat ion Tank
Stabilization timec: 2.50 day - C Reaeration t
Stabilization tank turnovers: 3.91 OUR:
Oxygen supply: 227 kg/hr (500 Ib/hr)
Fina 1 Clar if ier
Surface overflow rate: 48.6 cu m/day/sq m (1,191 g
Clarifier detention time3: 1.29 hours Clarifier
Clarifier solids loading: 181,048 g/day/sq m (37.1
ime : 1.37 hours
pd/ft2)
turnovers: 4.14
1b/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c, S = static condition; C = continuous flow.
-------
Table
(continued). OPERATING DATA FOR RUN NO.
Character is tics
PH
Settleable sol ids
Total sol ids
Total volatile solids
Suspended so) i ds
Suspended volatile solids
Total 3GD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total co! i form
Feca 1 col i form
COD
Units
mg/ 1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/I
mg/1
mg/1
rug/1
/7ml
/Ynl
mn/1
Grit Contact
tank tank
7.25 7-20
9.0
676
360
420 2670
30n 1C, no
136
60
193
21 .1
5-37
840000
73000
515
Stabilization DWP Final
tank clarifier clarifier
7-22 7.55
Trace
384
153
32/40 486 17
4940 294 10
2050 156 23
5
2500 25
19
7-7
0.75
510DO
2500
52
Percent
removal
43.2
57- 5
96.0
96.7
87.6
91.7
37.0
61.2
63.5
86.0
93-9
96.8
89.9
-------
Table C44. OPERATING DATA FOR RUN NO. 44
Date:
Start:
Vo 1 ume
August 9,
10:00 am
Treated :
1973
Stop:
12,195 cu
2.56
m (3,
pm
222,000
Durat ion :
gal Ions)
4
.94
hours
Average flow rate: 59,235 cu m/day (15.65 mgd)
Average transfer rate: 27,858 cu m/day (7.36 mgd) Percent return; 47
Average dry weather plnat flow rate: 49,205 cu m/day (13 mgd)
Contact Tank
MLSS: 3,210 mg/1 Contact time3: 15-31 min
BOD loading: 11,712 g/cu m/day (732 lb/day/1000 ft3)
F/Mb: 3.67 kg BOD/day/kg MLSS Air flow: 52.5 cu m/min (1,875 cfm)
Air supply: 6.9 cu m/kg BOD applied (112 ftVlb BOD applied)
Stabi1izat ion Tank
Stabilization timec: 2.80 days - C
Stabilization tank turnovers: 3.81
Oxygen supply: 227 kg/hr (500 Ib/hr)
Reaeration time:
OUR:
1 .30 hours
Fi na1 CIari f i er
Surface overflow rate: 41.5 cu m/day/sq m (1,017 gpd/ft )
Clarifier detentiom time3: 1.44 hours Clarifier turnovers: 3-43
Clarifier solids loading: 195,200 g/day/sq m (40.0 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C44 (continued). OPERATING DATA FOR RUN NO. 44
Characteristics
PH
Sett leable sol ids
Total sol ids
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total SOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as [1
Total phosphorus as P
Tota 1 col i form
Feca 1 col i form
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
,Vml
r/ml
mg/1
Grit Contact
tank tank
7.20 7.25
6.0
640
232
317 3210
164 1820
184
67
160
46
22.4
4.92
40000
435
Stabilization DWP Final
tank clarifier clarifier
7.15 7.90
9-0
525
192
9370 995 164
5650 590 95
2200 348 66
42
4000 72
33
15.6
5.51
22300
183
Percent
removal
18.0
31.9
48.3
42.1
64.1
37.3
57.1
28.3
30.4
44.2
62.3
-------
Table C45. OPERATING DATA FOR RUN NO. 45
Date: August 23, 1973
Start: 10:51 am Arop: 3:51 pm Duration: 5-00 hours
Volume treated: 11,949 cu m (3,157,000 gallons)
Average flow rate: 57,3^3 cu m/day (15-15 mgd)
Average transfer rate: 26,331 cu m/day (6.97 mgd) Percent return; 4(
Average dry weather plant flow rate: 60,560 cu m/day (16 mgd)
Contact Tank
MLSS: 3,700 mg/I Contact time3: 15.92 min
BOD loading: 8,128 g/cu m/day (508 lb/day/IOOO ft3)
F/Mb: 2.21 kg BOD/day/kg MLSS Air flow: 39.2 cu m/min (1,400 cfm)
Air supply: 7.5 cu m/kg BOD applied (121 ftVlb BOD applied)
Stabi1ization Tank
Stabilization timec: 2.61 days - C
Stabilization tank turnovers;. 3-65
Oxygen supply: 227 kg/hr (500 Ib/hr
Reaeration time:
OUR:
1 .37 hours
Final Clarifier
Surface overflow rate: 40.1 cu m/day/sq m (984 gpd/ft )
Clarifier detention timea: 1.50 hours Clarifier turnovers: 3.33
Clarifier solids loading: 216,184 g/day/sq m (44.3 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C45 (continued). OPERATING DATA FOR RUN NO. 45
Character i st ics
pH
Sett 1 eable sol ids
Tota 1 sol i ds
Total volatile solids
Suspended sol i ds
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kj el da hi nitrogen as .M
Total phosphorus as P
To ta 1 co 1 i f o rm
Fecal col i form
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
/Vml
mg/1
Grit Contact
tank tank
7.65 7.40
5.5
569
238
229 3700
144 2450
132
46
152
41
17.3
4.44
750000
1600
400
Stabilization DV/P Final
tank clarifier clarifier
7.10 7.75
Trace
451
161
11275 16 32
6925 12 20
3000 9 19
6
4250 30
17
11 .0
1.17
80000
500
71
Percent
reroova 1
20.7
32.4
86.0
86.1
85.6
87.0
80.3
58.5
36.4
73.6
89.3
68.8
82.2
-------
Table C46. OPERATING DATA FOR RUN NO.
General
Date: September k, 1973
Start: 11:46 am Stop: 5 = 51 pm Duration: 6.06 hours
Volume treated: 15,999 cu m (4,227,000 gallons)
Average flow rate: 63,361 cu m/day (16.74 mgd)
Average transfer rate: 19,001 cu m/day (5-02 mgd) Pe-cent return; 30
Average dry weather plant flow rate: 60,560 cu m/day (16 mgd)
_ _____ _ Contact Tank _
MLSS: 3,025 mg/1 Contact time3: 16.18 min
BOD, loading: !l,040 g/cu m/day (690 lb/day/1000 ft3)
F/M°: 3-67 kg BOD/day/kg MLSS Air flow: 31-5 cu m/min (1,125 cfm)
Air supply: 4.4 cu m/kg BOD applied (72 ft^/lb BOO applied)
_ Stabilization Tank _ ______
Stabilization timec: 1.67 days - C Reaeration time: 1.88 hours
Stabilization tank turnovers: 3-22 OUR:
Oxygen supply: 227 kg/hr (500 )b/hr)
Fina 1 C I ar i f i er
Surface overflow rate: 44.3 cu m/day/sq m (1,087 gpd/ft^)
Clarifier detention time3: 1.52 hours Clarifier turnovers: 3-98
Clarifier solids loading: 17^,216 g/day/sq m (35-7 lb/day/ft^)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C46 (continued). OPERATING DATA FOR RUN NO. 46
Character is t ics
pH
Sett leab le sol i ds
Tota 1 solids
Total volat i le sol i ds
Suspended sol ids
Suspended volatile solids
Tota! SOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Tot. a 1 co 1 i form
Fee a 1 co! i form
COJ
Uni ts
ml /I
mg/1
mg/1
mg/1
mq/l
nig /I
nig/ 1
rng/1
mg/1
mg/1
mq/l
/7ml
•Ynl
mg/1
Grit Contact
tank tank
7-33 7-12
13
1037
46?
659 3025
337 2050
162
4fi
240
34
22
5.90
1 9000
7000
W
Stabilization DWP Final
tank clarifier clarifier
7.12 7.55
Trace
375
160
1 DoOn "3 ^ r h
7100 30 54
23no 16 26
10
3750 32
16
11.2
2.19
3600
140
34
Percent
removal
63.8
65-9
91.3
84.0
84.0
79-2
36. 7
52.9
49.1
62.9
54.7
98 . n
8f-.fi
-------
Table C47. OPERATING DATA FOR RUN NO. 47
Date: September 17, 1973
Start: 7:51 am Stop: 3-08 pm Duration: 7-28 hours
Volume treated: 18,032 cu m (4,764,000 gallons)
Average flow rate: 59,462 cu m/day (15-71 mgd)
Average transfer rate: 27,933 cu m/day (7-38 mgd) Percent return; 47
Average dry weather plant flow rate: 68,130 cu m/day (18 mgd)
Contact Tank
MLSS: 3,450 mg/1 Contact time3: 15.25min
BOD loading: 6,832 g/cu m/day (427 lb/day/1000 ft3)
F/Mb: 1.99 kg BOD/day/kg MLSS Air flow: 31.5 cu m/min (1,125 cfm)
Air supply: 7.2 cu m/kg BOD applied (116 ft^/lb BOD applied)
CO
Stabilization Tank
Stabilization time : 3-5 days - S Reaeration time: 1.36 hours
Stabilization tank turnovers: 5-35 OUR:
Oxygen supply: 227 kg/hr (500 Ib/hr)
____^_^ Final Clarifier
Surface overflow rate: 41.7 cu m/day/sq m (1,021 gpd/ft^)
Clarifier detention time3: 1.44 hours Clarifier turnovers: 5-07
Clarifier solids loading: 210,816 g/day/sq m (43.2 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C47 (continued). OPERATING DATA FOR RUN NO. 47
VD
Character is t ics
pH
Settleable sol ids
Total sol Ids
Total volat i le sol ids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kj el da hi nitrogen as M
Total phosphorus as P
Total col i form
Feca 1 col i form
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/ 1
mg/1
mg/1
mg/1
mg/ 1
mg/1
mg/1
,7/ml
.?/ml
mg/1
Grit Contact
tank tank
7.50 7.10
4.5
539
237
334 3450
188 2000
107
47
115
41
14.3
5.23
47000
8700
400
Stabilization DWP Final
tank clarifier clarifier
7.00 7-22
Trace
435
169
10075 35 66
6075 12 33
2850 24 38
11
41
21
12.5
4.95
22300
3100
115
Percent
remova 1
19.3
28.7
80.2
79.8
64.5
76.6
64.3
48.8
12.6
5.4
5K5
64.4
71.2
-------
Table C^8. OPERATING DATA FOR RUN NO. 1*8
General
Date: September 21 , 1973
Start: 3:52 pm Stop: 9:10 pm Duration: 5.28 hours
Volume treated: 11,983 cu m (3,166,000 gallons)
Average flow rate: 5^,^66 cu m/day (1^.39 mgd)
Average transfer rate: 23,959 cu m/day (6.33 mgd) Percent return;
Average dry weather plant flow rate: 68,130 cu m/day (18 mgd)
Contact Tank
MLSS: 3,800 mg/1 Contact time3: 17.00min
BOD loading: 10,M6 g/cu m/day (651 lb/day/1000 ft3)
M F/M : 2.76 kg BOD/day/kg MLSS Air flow: 36.k cu m/min (1,300 cfm)
g" Air supply: 5-1* cu m/kg BOD applied (88 ftVlb BOD applied)
Stabilization Tank
Stabilization time0: 3.0 days - S
Stabilization tank turnovers: 3-33
Oxygen supply: 227 kg/hr (500 Ib/hr)
Reaeration time:
OUR:
1 .59 hours
Final Clarifier
Surface overflow rate: 38.! cu m/day/sq m (935 gpd/ft2)
Clarifier detention time : 1.60 hours Clarifier turnovers: 3-30
Clarifier solids loading: 208,376 g/day/sq m (42.7 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C48 (continued). OPERATING DATA FOR RUN NO. 48
Characteristics
pH
Sett leable sol ids
Total sol i ds
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as N
Total phosphorus as P
Total col iform
Fecal col iform
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
#/ml
#/ml
mg/1
Grit Contact Stabilization
tank tank tank
7.15 7.20 7.15
7.5
577
235
321 3800 11775
183 2400 7750
178 3600
49
120 3900
22
13-2
3-96
1350000
135000
1416
DWP Final
clarifier clarifier
7.62
Trace
368
80
186 52
137 42
30 81
10
36
16
6.3
1.56
160000
11000
86
Percent
removal
36.2
66.0
83.8
77.0
54.5
79.6
70.0
27.3
52.3
60.6
88.1
91.8
93.9
-------
r-o
-t-
K>
Table C49- OPERATING DATA FOR RUN NO. 49
General
Date: September 2k, 1973 to September 25, 1973
Start: 10:30 pm Stop: 10:00 am Duration: 11.50 hours
Volume Treated: 30,178 cu m (8,973,000 gallons)
Average flow rate: 62,982 cu m/day (16.64 mgd)
Average transfer rate: 22,029 cu m/day (5-82 mgd) Percent return; 35
Average dry weather plant flow rate: 75,700 cu m/day (20 mgd)
Contact Tank
MLSS: 3,100mg/l Contact time3: 15.68mln
BOD loading: 5,152 g/cu m/day (322 lb/day/1000 ft3)
F/Mb: 1.67 kg BOD/day/kg MLSS) Air flow: 36.4 cu m/min (1,300 cfm)
Air supply: lt.0 cu m/kg BOD applied (179 fWlb BOD applied)
Stabilization Tank
Stabilization time0: 2.5 days - S
Stabilization tank turnovers: 7-02
Oxygen supply: 227 kg/hr (500 Ib/hr)
Reaeration time:
OUR:
hours
Final Clarifier
Surface overflow rate: 44.1 cu m/day/sq m (1,081 gpd/ft2)
Clarifier detention timea: 1.48 hours Clarifier turnovers: 7-70
Clarifier solids loading: 183,976 g/day/sq m (37-7 lb/day/ft2)
a. Based on total flow.
b. Based on MLSS in contact tank only.
c. S = static condition; C = continuous flow.
-------
Table C49 (continued). OPERATING DATA FOR RUN NO.
jr-
*_(O
Characteristics
pH
Settleable sol ids
Total sol i ds
Total volatile solids
Suspended sol ids
Suspended volatile solids
Total BOD
Dissolved BOD
Total organic carbon
Dissolved organic carbon
Kjeldahl nitrogen as M
Total phosphorus as P
Total col iform
Feca 1 col i form
COD
Units
ml/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
/7/m 1
,Vml
mg/1
Grit Contact
tank tank
7.15 6.90
5-1
487
173
222 3100
03 1700
76
26
90
33
6.7
2.65
1090000
39000
301
Stabilization DWP Final
tank clarifier clarifier
6.90 7.42 7-71
Trace
357
100
11225 10 22
6500 4 3
3850 9 17
15
4450 30
27
5.0
1.23
76oooa
7100
51
Percent
removal
26.7
42.2
90.1
90.9
77.6
42.3
66.7
13.2
25-4
53.6
30.2
81.7
83.0
-------
APPENDIX D. Procedures for Sludge Studies
DAILY PROCEDURES FOR STABILIZATION TANK STUDIES
1. Record the sludge volume in the stabilization tank.
2. Record the rate of flow of WAS into the stabilization tank (1973
only).
3. Record the mean air temperature.
k. Record the DWP's influent suspended solids (1973 only).
5. Record the number of days that the sludge has been under static
or dynamic conditions.
6. Obtain a sludge sample for analysis of suspended solids and
volatile suspended solids.
7- Use a YSI dissolved oxygen meter to determine the temperature
and OUR of the sludge. The OUR was based on the change in
dissolved oxygen in a period of three minutes (or six minutes if
the rate of change was low),
8. Run a settling test. This consisted of taking one liter of sludge
from the stabilization tank and mixing it with three liters of
raw sewage from the influent to the DWP grit tank. The mixture
was aerated for 15 minutes andjthen one liter of the mixed
liquor was poured into a settling column. The settling rate was
recorded and after 30 minutes the settled sludge volume was
recorded. A sample of the supernatant was also analyzed for
suspended sol ids concentration.
9. If the sludge was in a static condition *he time under static
condition was recorded as the sludge age. If the sludge was
under dynamic conditions, the recorded rate of WAS flow into the
tank and the sludge volume were used to calculate the sludge
detention time in the tank. This values was then used as the sludge
age. If the conditions changed from static to dynamic, the sludge
age was based on an average of old sludge remaining before a
complete tank turnover and the detention time for the new sludge
that was being pumped in.
10. The recorded value of oxygen uptake (mg/l/hr) was divided by the
value of volatile suspended solids to get an OUR in terms of
(mg/l/hr)/(gm VSS).
11. Using the data obtained, the sludge volume index (SVl) was
calculated and recorded. The calculations were as follows:
244
-------
MLSS = (.25) SS concentration of sludge
+ (.75) SS concentration of plant influent
SVI = settled sludge volume x 1000/MLSS
PROCEDURES FOR BENCH SCALE STUDIES
The equipment used for the bench scale testing included three 12 liter
plastic reactors, a Millipore vacuum-pressure pump, six ball diffusers,
a 1000 ml settling column with a bottom drawoff point, a YSI dissolved
oxygen meter and dissolved oxygen probe, magnetic stirrer, a plastic
air pressure chamger with a pressure gauge, and a bicylce air pump.
The first procedure used was for studying the extent of aerobic
digestion. Six to seven liters of DWP WAS was placed in two of the
plastic reactors. This sludge would be identical to the sludge
entering the demonstration system stabilization tank. The Millipore
pump was then turned on to deliver a continuous supply of air to the
two units through two ball diffusers at the bottom of each reactor.
After this initial setup the units were allowed to run for periods
ranging from 15 to 20 days. Samples of the sludge were taken daily
and analyzed for suspended solids concentration, volatile suspended
solids concentration and OUR. In addition, spot checks were made to
determine total alkalinity and total COD concentrations. The data
collected was then analyzed to determine, 1) the rate of solids
destruction, 2) if there is a noticeable relationship between the
OUR and the decrease in solids, and 3) what is happening to the total
COD and the total alkalinity.
The second aspect of the bench scale testing was the effect of sludge
stabilization on the dissolved air flotation thickening process.
Every second day during the digestion period a bench scale flotation
test was run using 330 ml of the sludge under aeration in the plastic
reactors. These tests were run using parameters similar to those
used by the Kenosha WPCP in the operation of their flotation units.
The operational parameters were: 200% recycle of primary effluent
pressurized at 3-16 kg/sq m (45 psig).
The 330 ml sample of sludge was placed in the 1000 ml cylinder. A
sample of primary effluent was obtained from the DWP and this sample
was placed in the plastic pressurizing chamber. The pressure was
the increased to 3.16 kg/sq cm (A5 psig) in the chamber and the chamber
was shaken vigorously for one minute and then allowed to sit for 3
minutes. After 3 minutes the saturated recycle was released into the
bottom of the cylinder until the volume of the cylinder reached 1000 ml.
Once the cylinder was filled, 15 minutes were allowed for the solids
245
-------
to float to the surface. Upon completion of the test, a sample of the
top float was taken with a spoon and an effluent sample was drawn off
from the bottom of the cylinder.
From the flotation test the following data was obtained: the interface
rise rate during the 15 minutes of flotation, the percent solids in the
float, calculated as (weight of dried solids/weight of wet solids) x
100, suspended solids concentration in the effluent, volume of the
float, volume of the effluent, and the percent SS recovery. This last
term was calculated as follows:
(mg SS in - mg SS out)/mg SS in =
([volume of recycle) (SS of primary effluent) +
(volume of sludge) (SS of sludge) - (volume of effluent)
(SS of effluent)] T [(volume of recycle) (SS of primary effluent)
+ (volume of sludge) (SS of sludge)].
The final portion of the study was the bench scale tests run only
during actual operation of the demonstration system, insuring the
raw flow used had combined sewage characteristics. During a run, six
liters of raw flow (grit tank effluent) were taken and placed in a
plastic reactor. Two liters of stabilized sludge were drawn off from
the digestion units and mixed with the six liters of raw flow. This
mixture was then aerated vigorously for 15 minutes (contact time) and
then allowed to settle for one hour (clarifier detention time). After
the 15 minutes of aeration, 1000 ml of the mixed liquor was also drawn
off and placed in the settling column, and 30 minutes later the volume
of settled sludge was recorded. Samples were taken of the raw flow,
mixed liquor, and supernatant after one hour of settling. Data
compiled during these tests included SS and VSS concentrations of
the raw flow, SS and VSS concentrations of the mixed liquor, SS and
VSS concentrations of the supernatant, and SVI. These results were
used in calculating the percent SS and VSS removals for each run and
the percent volatile solids in the mixed liquor. The results of
these tests were used to determine the effect of different stabiliza-
tion times on the effectiveness of the sludge in the demonstration
system.
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-670/2-75-019
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
BIOLOGICAL TREATMENT OF COMBINED SEWER OVERFLOW AT
KENOSHA, WISCONSIN
5. REPORT DATE
April 1975; Issuing Date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Robert W. Agnew, Charles A. Hansen, Michael J. Clark,
0. Fred Nelson, and William H. Richardson
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
City of Kenosha, 625 52nd Street, Kenosha, Wl 53140
Through subcontract with
Envirex Inc., 5103 W. Beloit Road, Milwaukee, Wl
53214
10. PROGRAM .ELEMENT NO.
1BB034; ROAP 21-ASY; Task 139
11.X»J«XKXSrK'GRANT NO.
I I 023 EKC
12. SPONSORING AGENCY NAME AND ADDRESS
National Environmental Research Center
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
Final 9/69-H/73
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This report describes the design, construction, operation and two-year evaluation of
a biological process used for the treatment of potential combined sewer overflow. A
75,700 cu m/day (20 mgd) modified contact stabilization process was constructed on
the grounds of an existing 87,055 cu m/day (23 mgd) conventional activated sludge
plant at a total cost of I.I million dollars. The demonstration system consisted of
pumping facilities, the conversion of an unused flocculation basin into a grit basin,
construction of a contact tank and stabilization tank, installation of a final clari-
fier and all associated yard piping and automatic control equipment. The demonstration
system's raw sewage pump and clarifier were used by the dry weather plant when the
demonstration system was not in use. Results from the evaluation program proved the
demonstration system to be a feasible concept for the treatment of potential combined
sewer overflow. The system was operated and evaluated during 49 runs in which
681,300 cu m (180,000,000 gal.) of potential overflow was treated. Based on these
tests, expected removal efficiencies for suspended solids, BOD, and TOC are 90%, 85%,
and 76%, respectively. Operating costs for running the system 300 hours per year are
estimated at 3-5671. NO. OF PAGES
259
20. SECURITY CLASS (This page)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
247
•fy U. S. GOVERNMENT PRINTING OFFICE: 1975-657-592/5363 Region No. 5-I I
------- |