WATER POLLUTION CONTROL RESEARCH SERIES 11022 ECV 09/71
Underwater Storage of
Combined Sewer Overflows
U.S. ENVIRONMENTAL PROTECTION AGENC\
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WATER POLLUTION CONTROL RESEARCH SERIES
The Water Pollution Control Research Reports describe the results and progress
in the control and abatement of pollution of our Nation's waters. They provide
a central source of information on the research, development and demonstration
activities of Water Quality Research of the Environmental Protection Agency,
through in-house research and grants and contracts with the Federal, State
and local agencies, research institutions, and industrial organizations.
Previously issued reports on the Storm and Combined Sewer Pollution Control
Program:
11023 FDB 09/70
11024 FKJ 10/70
11023 DZF 06/70
11020 FAQ 03/71
11022 EFF 12/70
11022 EFF 01/71
11022 DPP 10/70
11024 EQG 03/71
11020 FAL 03/71
11024 DOC 07/71
11024 DOC 08/71
11024 DOC 09/71
11024 DOC 10/71
11040 GKK 06/70
11024 DQU 10/70
11024 EQE 06/71
11024 EJC 10/70
11024 EJC 01/71
11024 FJE 04/71
11024 FJE 07/71
11023 FDD 07/71
11024 FLY 06/71
11034 FLU 06/71
11024 FKM 12/71
Chemical Treatment of Combined Sewer Overflows
In-Sewer Fixed Screening of Combined Sewer Overflows
Ultrasonic Filtration of Combined Sewer Overflows
Dispatching System for Control of Combined Sewer Losses
Prevention and Correction of Excessive Infiltration and
Inflow into Sewer Systems - A Manual of Practice
Control of Infiltration and Inflow into Sewer Systems
Combined Sewer Temporary Underwater Storage Facility
Storm Water Problems and Control in Sanitary Sewers -
Oakland and Berkeley, California
Evaluation of Storm Standby Tanks - Columbus, Ohio
Storm Water Management Model, Volume 1 - Final Report
Storm Water Management Model, Volume II - Verification
and Testing
Storm Water Management Model, Volume III -
User's Manual
Storm Water Management Model, Volume IV - Program Listing
Environmental Impact of Highway Deicing
Urban Runoff Characteristics
Impregnation of Concrete Pipe
Selected Urban Storm Water Runoff Abstracts, First Quarterly
Issue
Selected Urban Storm Water Runoff Abstracts, Second Quarterly
Issue
Selected Urban Storm Water Runoff Abstracts, Third Quarterly
Issue
Selected Urban Storm Water Runoff Abstracts, July 1970 -
June 1971
Demonstration of Rotary Screening for Combined Sewer
Overflows
Heat Shrinkable Tubing as Sewer Pipe Joints
Hydraulics of Long Vertical Conduits and Associated Cavitation
Urban Storm Runoff and Combined Sewer Overflow Pollution -
Sacramento, California
Continued on inside back cover
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UNDERWATER STORAGE
OF
COMBINED SEWER OVERFLOWS
by
Karl R. Rohrer Associates, Inc,
529 Grant Street
Akron, Ohio 44311
for
ENVIRONMENTAL PROEECTION AGENCY
Program # 11022 ECV
Contract # 14-12-143
September 1971
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C., 20402 - Price $1.50
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EPA Review Notice
This report has been reviewed by the Environmental
Protection Agency and approved for publication. Approval
does not signify that the contents necessarily reflect
the views and policies of the Environmental Protection
Agency, nor does mention of trade names or commercial
products constitute endorsement or recommendations for
use.
ii
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ABSTRACT
The purpose of this study was to demonstrate off-shore under-
water temporary storage of storm overflow from a combined
sewer in flexible tanks. Site selection, model testing, system
design, construction, and one year's operation were conducted
under the study.
A pilot demonstration facility was constructed in ._£^ndusky,
G>hjy3 where combined sewer overflow from a 14.86-acre resi-
dential drainage area was directed to two-100,000 gallon
collapsible tanks anchored underwater in Lake Erie. The
stored overflows were pumped back to the sewer system after
a storm event for subsequent treatment. During the year's
operation, a total of 988,000 gallons of storm overflow was
contained and returned for treatment.
As constructed, the facility cost was about $1.88 per gallon
of storage capacity while future projections indicate costs
of less than $0.40 per gallon possible.
Evaluation of the underwater storage system in controlling
combined sewer pollution, comparison of cost with other stor-
age methods and other combined sewer pollution control methods,
operational difficulties and recommendations of an improved
system are included in the study report.
This report was submitted in fulfillment of Contracts 14-12-
25 and 14-12-143 between Water Quality Research, Environmen-
tal Protection Agency, and Karl R. Rohrer Associates, Inc.
Pursuant to Executive Reorganization Plan Number Three of
1970, effective December 2, 1970, and Environmental Protec-
tion Agency Order Numbers 1110.1 and 1110.2, all references
to Federal Water Quality Administration or Federal Water Pol-
lution Control Administration herein shall be to the
Environmental Protection Agency, Water Quality Research.
111
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CONTENTS
Section Page
I Conclusions 1
II Recommendations 3
III Introduction 5
IV Site Investigation 7
V System Design 43
VI Construction 79
VII Operation Period 91
VIII Evaluation 115
IX Acknowledgements 129
X Awards 131
XI Patents 133
XII Bibliography 135
XIII Glossary 139
XIV Abbreviations 143
XV Appendices 145
v
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FIGURES
No. Page
1. Preliminary Site Locations 9
2. Combined Sewer Outfalls, Sandusky, Ohio 15
3. Sandusky Bay 18
4. Lake Erie Water Level 20
5. Intensity - Duration - Frequency 28
6. Monthly Precipitation Probabilities
Sandusky, Ohio 29
7. Yearly Precipitation Probability
Sandusky, Ohio 30
8. Monthly Maximum Daily Precipitation
Sandusky, Ohio 31
9. Annual Maximum Daily Precipitation
Sandusky, Ohio 32
10. McEwen Street Drainage Area 33
11. McEwen Street Drainage Area 34
12. Combined Sewers - McEwen Street Drainage
Area 35
13. McEwen Street Outfall 37
14. Subsurface Boring Locations 39
15. Underwater Tank 47
16. Tank Height Above Tank Frame Versus
Volume (West Tank) 48
17. Tank Height Above Tank Frame Versus Tensile
Force in Fabric (West Tank) 49
18. Tank Height Above Tank Frame Versus Fabric
Elongation (West Tank) 50
VI
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No. Page
19. Tank Height Above Tank Frame Versus
Internal Pressure (West Tank) 51
20. Tank Volume versus Fabric Elongation
(West Tank) 52
21. Fabric Clamping Details 54
22. Sedimentation Chamber 56
23. Ratio of Partical Size to Velocity Required
For Erosion, Transportation, and Deposition.
(After Hjulstrom) 57
24. Gas Vent Valve 61
25. Pressure Relief Valve as Installed on West
Tank 63
26. Tank Level Control System (T.L.C.S.) 64
27. Tank Level Control System (T.L.C.S.) 65
28. Connection Chamber 66
29. Sewage Pump 68
30. Automatic Sampler 71
31. Storm Event Filling Tanks Flow Diagram of
Underwater Storage System 72
32. Emptying Tanks Flow Diagram of Underwater
Storage System 75
33. Plot Plan 77
34. Construction 80
35. West Tank Diversion Cone 84
36. West Tank Sedimentation Chamber 84
37. Underwater Storage Tanks 87
38. Underwater Storage Tanks 89
39. Typical Installation - Temporary Underwater
Storage of Combined Sewer Storm Overflow 119
VI1
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No. Page
40. Two-Ply Neoprene Coated 13 Oz.
Nylon Fabric 154
41. Single-Ply Neoprene Coated 13 Oz.
Nylon Fabric 155
42. Fabritank Use Temperature Range 156
Vlll
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TABLES
No. Page
1. Site Investigation - Sites Proposed 8
2. Final Site Selections - Sites Proposed 10
3. Project Approvals 12
4. Sandusky, Ohio - Normals, Means, and
Extremes 21-22
5. Precipitation Sandusky Pilot Facility
Foot of McEwen Street - Sandusky, Ohio 24
6. Storm Events - Sandusky Pilot Facility
Sandusky, Ohio 25-26
7. Test Borings 40
8. Tank Storage Data 92-99
9. Summary of Tank Storage Data 100
10. Flowmeter Operation 107-109
11. Pilot Facility Construction Costs 117
12. Construction Cost Per Gallon of Storage
Capacity - Pilot Facility, Sandusky, Ohio 118
13. Construction Cost for 200,000 Gallon Storage
Capacity Based on 6% Working Fabric Elongation 120
14. Construction Cost for 200,000 Gallon Storage
Capacity Based on 8% Fabric Elongation,
Modular Tank Design, and Minimum Wave Force 120
15. Storage Capacity Construction Cost Comparison
(Based on Costs for Sandusky, Ohio Area) 122
16. Combined Sewer Pollution Abatement
Cost Comparison 123-125
IX
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SECTION I
CONCLUSIONS
1. Off-shore temporary underwater storage of storm over-
flow from combined sewers in flexible underwater storage
tanks is feasible and was demonstrated successfully in the
pilot facility at Sandusky, Ohio.
2. In order to minimize operation and maintenance costs,
the system must be gravity fed, a minimum of pretreatment
prior to the storage tank must be possible, electricity
cost for pumps, compressors, and instrumentation must be
kept to a minimum, and the system must be able to operate
automatically with a minimum of scheduled maintenance.
3. Underwater storage of combined sewer overflows can
be competitive with other methods of storage where land
is not available and physical and hydraulic site character-
istics permit. River and lake installations have different
controlling design parameters.
4. A modular tank system should be designed for larger
drainage areas. For economical use of the underwater stor-
age system, a 250,000 gallon to 500,000 gallon basic unit
should be used. Site characteristics would determine op-
timum tank size.
5. Life expectancy for neoprene rubber coated nylon fabric
(or other) must be determined in full scale operation in
the environment imposed. Aging and subsequent loss of
fabric strength must be determined.
6. Insufficient data is available on pollution loads
from combined sewer overflows and pollution loads from
storm sewer overflow.
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SECTION II
RECOMMENDATIONS
General
1. Further operation of the pilot facility for a minimum
of one year should be completed to acquire sufficient data
for pollution control evaluation.
2. Study of detention time of stored liquid should be
completed to determine action of underwater storage on
overflows.
3. Investigation of further combined sewer overflows
should be studied in detail for application of off-shore
temporary underwater storage of combined sewer overflows
in a full scale application and to determine combined
sewer pollution loads. Separate storm sewer pollution
loads should also be determined for a similar area.
4. Collection of grab samples of all flows should be
used liberally to confirm results from automatic samplers.
System Design
1. The fabric elongation in the two-ply neoprene coated
nylon fabric should be limited to six percent working elon-
gation. Elongation up to twelve percent should be studied.
Physical and chemical properties of the fabric on aging in
the proposed environment should be studied.
2. Tank design should be modular with a 250,000 gallon
basic design capacity. Where site conditions permit high-
er tank capacities up to about 500,000 gallons might be
used.
3. On future installations only the following items would
be required:
a. Site preparation,
b. Connection chamber with bar screen,safety
overflow, and piping to underwater tank,
c. Tank and anchorage,
d. Pressure relief valve,
e. Underground pump station,
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f. Tank full indicator to close influent
control valve.
4. Check valves should, where necessary, be included on
the influent pipe beyond the influent control valves.
5. Future installations could use an underground prebuilt
pump station for pumps and control structure.
6. The flushing system to help remove sediment from with-
in the tank could possibly be eliminated in future designs.
7. The tank level control system should be replaced by a
non or minimum power using method. It is not necessary to
continuously monitor tank volume. Control valve operation
could be initiated by internal pressure or fabric tension
sensors.
8. Only one gas vent valve need be used with existing
tank shape and design. The gas vent valve could use soft
seats and a plastic ball float.
9. The pressure relief valve should be used on all stor-
age tanks. An adaptation of a commercially available mag-
netic-gravity valve might be more maintenance free.
10. Future underwater storage systems should have ability
to fill the tank with bay or river water and should be
checked annually. Divers should check each installation
periodically.
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SECTION III
INTRODUCTION
Purpose of Project
The past decade has brought an increasing awareness of the
pollution load contributed to the nation's water resources
by combined sewer collection systems. Many cities adopted
the combined manner of sewer construction due to an economic
savings when compared to separate storm and sanitary sewers.
As a result, over 54 million people in 1329 jurisdictions
with a total area of 3,029,000 acres are served by combined
sewer systems in the United States today-
A basic point to remember is that combined sewers are/have
been designed to overflow. Under today's condition of in-
creasing urban growth, a spreading asphalt and concrete
barrier increases runoff volumes and rates and these over-
flows increase in frequency and duration.
&
Methods are being studied on how to eliminate the pollution
problem presented by combined sewer overflows. Separation
of sewers is economically unfeasible and does not allow
treatment of the storm runoff. Complete treatment at each
outfall is not feasible.
This project demonstrates a method of reduction of combined
sewer pollution. Since most regulator - outfalls are at a
river or lake, temporary storage of the storm overflow in
underwater flexible tanks with pumping of the overflow to
the existing interceptors and to existing water pollution
control stations for treatment during non-peak hours is a
possible method of control.
Underwater storage, where applicable, offers lower land
costs, a more aesthetically pleasing and compatible instal-
lation, and an economical method of elimination of combined
sewer pollution.
Scope of Project
The Scope of the Project was broken down into three distinct
areas. The first area of work consisted of:
1. Site investigations,
2. Aguisition of property use and access rights,
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3. Topographic and hydrographic surveys,
4. Hydraulic studies,
5. Hydraulic, structural, and instrumentation design, and,
6. Specifications and construction drawings.
The second area of work consisted of:
1. Construction of pilot facility.
The third area of work consisted of:
1. Operation of pilot facility for one year,
2. Evaluation of one year of operation, and
3. Removal or continued operation of pilot
facility.
Project Objectives
The primary objectives of the project were to:
1. Obtain an operable system and operating procedures,
2. Find the total cost of storage and the cost/pound of
BOD reduction and compare underwater storage with
other methods of storage and treatment including
sewer separation, and
3. Determine the degree of pollution control provided.
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SECTION IV
SITE INVESTIGATION
The first phase of the work to be completed under the
demonstration pilot facility study was the selection of
a site where the facility could be constructed, the acqui-
sition of property use and access rights, topographic and
hydrographic surveys, hydrologic studies, hydraulic, struc-
tural and instrumentation design, and preparation of com-
plete specifications and construction drawings.
Site Selection
The F.W.P.C.A. limitations imposed on site selection were:
1. Thirty acre combined sewer drainage area,
2. Simple non-mechanical regulator device,
3. Suitable water body conditions,
4. Minimum interference with waterway uses,
5. Ample workspace and access,
6. Property and right-of-way rights and permits avail-
able,
7. Adjacent area compatible and installation acceptable
to public, and
8. Total storage capacity 200,000 gallons.
Table 1 lists nine possible site locations presented to
the F.W.P.C.A. during January, 1967. The locations of
these sites are shown in Figure 1.
The nine potential site locations were reduced to the best
four locations and these were presented to the F.W.P.C.A.
during February, 1967. Table 2 describes these sites.
Rohrer recommended that the Sandusky, Ohio site be approved
as the demonstration pilot facility site from the prelim-
inary investigations conducted.
Tentative approval of the McEwen Street combined sewer
drainage in Sandusky, Ohio area was received from the F.W.
P.C.A. and work was begun on obtaining all permits and per-
missions necessary for the project. Design of the system
could not be completed until after site selection had been
accomplished. However, preliminary design plans had to be
completed to acquire permissions and permits necessary.
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TABLE 1
SITE INVESTIGATION
Sites Proposed
1. Akron, Ohio .... Riverside Blvd. Sewer District
2. Akron, Ohio .... Spalding-Weaver-Evers & Tallmadge
Sewer District
3. Avon Lake, Ohio . . Southpoint Sewer District
4. Avon Lake, Ohio . . Moorewood Avenue Outfall Sewer
5. Brecksville, Ohio
6. Cleveland, Ohio . . W. 110th Street Outfall Sewer
7. Huron, Ohio .... Outfall Sewer at Treatment Plant
8. Port Clinton, Ohio. Outfall Sewer at Water Works
9. Sandusky, Ohio. . . McEwen Street Outfall Sewer
Site No. 123456789
Site Criteria
A. Strictly Combined Sewer XXXXOXOXX
Estimated Drainage Area 28 95 85 290 45 29 65 69 22
(Acres) XOOOOXOOX
B. Water Body Depth XOXXOXXXO
Flood Velocity XOXXOXXXX
Bed Material OXXXXOXXX
C. Interference with
Other Water Way Uses XXXXXXOOX
D. Ample Work Space XXXXXOOXX
Convenient Access OXXXOOOXX
E. Permissions XXOXXOXXX
F. Compatible Adjacent Area XXXXXOOOX
Key
X - Indicates Good Condition
0 - Indicates Unfavorable Condition
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N
PORT CLINTON
SANDUSKY
I
OHIO
\
PRELIMINARY SITE LOCATIONS
KARL R. ROHRER ASSOCIATES, INC.
AKRON, OHIO
FIGURE I
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TABLE 2
FINAL SITE SELECTIONS
Sites Proposed
1. Akron, Ohio Riverside Blvd. Sewer District
2. Cleveland, Ohio W. 110th Street Outfall Sewer
3. Port Clinton, Ohio. . . . Outfall Sewer at Water Works
4. Sandusky, Ohio McEwen Street Outfall Sewer
Site No.
Site Criteria
A. Strictly Combined Sewer
Estimated Drainage Area (Acres)
B. Water Body Depth
Flood Velocity
Bed Material
C. Interference with other
water way uses
D. Ample Work Space
Convenient Access
X
28
X
X
X
0
X
X
0
X
29
X
X
X
0
X
O
0
X
69
0
X
X
X
0
X
X
X
22*
X
0
X
X**
X
X
X
E. Permissions X O X X
F. Compatible Adjacent Area X O O X
Key
X - Indicates Good Condition
0 - Indicates Unfavorable Conditions
* - With final study of the Sandusky site area, it was found
that the drainage area contains 14.86 acres.
**- With soil borings taken, unfavorable bedrock conditions
existed.
10
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Project Approvals
Permission or permits were required from the companies and
agencies listed in Table 3. All stated no objection to the
installation.
When continued operation after the one-year operation period
was considered, it was necessary to reobtain several permits
for the project since the original request for approvals for
the installation had been based on a one-year operation period
with subsequent system removal. The major approval reob-
tained was from the U.S. Army, Buffalo District, Corps of
Engineers since their permit was only good until December 13,
1969. On or prior to that date, the installation had to be
removed. An extension of time for operation of the install-
ation was requested; and, on January 7, 1970, a new permit
was issued requiring removing of the installation on or prior
to December, 1972.
Lake Erie
Lake Erie is the most southerly as well as the shallowest
of the five Great Lakes. Lake Erie covers a total of 9,910
square miles and has a drainage basin consisting of 32,630
square miles. The distance from Buffalo, New York at the
easterly end of the lake to Toledo, Ohio at the westerly
end of the lake is 241 miles with the greatest width being
about 57 miles.
The maximum depth in Lake Erie is 210 feet at a point just
southeast of Long Point, Ontario and it has an average depth
of 58 feet over the entire lake. Generally, the deepest
part of the lake is at the eastern end, while the island re-
gion at the westerly end is the most shallow.
During the winter, very heavy ice forms along the shore
line and extends some distance into the lake. The west-
erly end, or island region, is often quite solidly iced over.
The water temperature of Lake Erie fluctuates from about 75°
in the late summer or early fall to 32° during winter and
early spring.
The maximum wind velocity recorded on Lake Erie was 74 knots
(85 MPH) on June 10, 1963. However, recorded wind velocity
data was only begun in 1941; and, over a longer data inter-
val, this maximum wind velocity would with certainty increase.
Lake Erie Level
The average or normal elevation of the surface of Lake Erie
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TABLE 3
PROJECT APPROVALS
Agency
Interest
1.
2.
4.
5
Department of the Army
Buffalo District
Corps of Engineers
Buffalo, New York
Jurisdiction over all cons-
truction in navigable waters
in Lake Erie.
Ninth Coast Guard District All structures in navigable
Cleveland, Ohio waters must be marked in ac-
cordance with law.
City of Sandusky
Sandusky, Ohio
Farrell-Cheek Steel Co.
Sandusky, Ohio
Penn Central
Cleveland, Ohio
Ohio Department of Health
Columbus, Ohio
Permission to connect to ex-
isting combined sewer outfall.
Coordination with City of San-
dusky Water Pollution Con-
trol Station.
Upland property owner to East
of site.
Upland property owner to South
of site. Owner of leased pro-
perty for facility.
Approves all plans for water
pollution control stations
and associated facilities in
the State of Ohio.
7. Regional Director Protection of fish and wild-
Bureau of Fish and Wildlife life.
U.S. Department of Interior
8. Ohio Department of Natural Jurisdiction over all natural
Resources water bodies in State of Ohio.
Division of Water
9. Ohio Department of Natural Jurisdiction over all water-
Resources craft in Ohio Waters. Inter-
Division of Watercraft est in marking of tank loca-
tion.
10. Ohio Departments of Public Land in Lake Erie is under
Works jurisdiction of this agency.
Columbus, Ohio
12
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varies irregularly from year to year. During the course of
each year the surface is subject to a consistent seasonal
rise and fall, the lowest stages prevailing during the win-
ter months and the highest stages during the summer months.
In the 110 years from 1860 to 1969, the difference between
the highest (572.76) and the lowest (567.49) monthly mean
stages of the whole period has been 5.27 feet; the greatest
annual fluctuation as shown by the highest and the lowest
monthly means of any year was 2.75 feet; and the least annual
fluctuation was 0.87 foot. (International Great Lakes Datum,
1955. Elevations are in feet above mean water level in Gulf
of St. Lawrence at Father Point, Quebec. All elevations in
this report are referred to this datum.)
In addition to the annual fluctuations there are also os-
cillations of irregular amount and duration produced by
storms. Some with periods of a few minutes to a few hours
are the results of squall conditions. The fluctuations are.
produced by a combination of wind and barometric pressure
changes that accompany the squalls. At other times, the
lake level is affected for somewhat longer periods, such as
many hours or days by strong winds of sustained speed and
direction which drive the surface water forward to raise its
level on the lee shore and lower it on the weather shore.
This type of fluctuation has a very pronounced effect on
Lake Erie, because it is the shallowest of the Great Lakes
and afford the least opportunity for the impelled upper
water to return through reverse currents beneath the depth
disturbed by storms. As a result, the water level in the
harbors, particularly those near each end of the lake fluc-
tuates markedly under the influence of winds, varying with
the direction, strength, and persistence. The maximum effect
occurs at Sandusky and Toledo, Ohio and at the mouth of the
Detroit River.
Sandusky, Ohio
The City of Sandusky, Ohio is situated on the southeastern
shore of Sandusky Bay near the western end of Lake Erie. The
City of Sandusky is located approximately midway between
Cleveland, Ohio and Toledo, Ohio at a latitude of 41°27'
north and a longitude of 82°43' west.
Sandusky presently incorporates 9.1 square miles of land area
and 5.8 square miles of water area. The elevations of the
city vary between 575 and 603 feet. The land area is ex-
tremely flat. Few slopes exist which are greater than 1%.
The estimated 1969 population was 36,479.
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Sandusky Bay provides a natural harbor for shipping.
The City of Sandusky has over 11 miles of waterfront; and,
in 1968, the port ranked second on Lake Erie in coal tonnage
shipped.
The City of Sandusky is a center for water oriented recrea-
tion. Adjacent to the City of Sandusky, are East Harbor
State Park and Cedar Point which offer recreation to resi-
dents of Northern Ohio and many surrounding states. Both
provide beaches for swimming which are becoming scarce in
Lake Erie.
Water Pollution Control Station and Sewage Collection Sewage
At the present time, the City of Sandusky Water Pollution
Control Station offers primary treatment only. However, con-
struction of secondary treatment facilities with phosphate
removal is underway.
The City of Sandusky has developed the future plans for the
Water Pollution Control Station on a regional basis so that
both City and Erie County sanitary wastes will be treated
here. Erie County will provide proportional funds for se-
condary treatment and future expansion requirements. A
tributary area of 5,863 acres of City land area and 22,638
acres of County land area are presently anticipated to be
served by the City of Sandusky Water Pollution Control Sta-
tion. A design population of 83,000 for the year 2000 has
been used as the basis for secondary treatment design.
The 1967 average daily flow at the Water Pollution Control
Station was 6.2 MGD: the 1968 average daily flow was 7.7
MGD. The average daily flow for the first 9 months of 1969
was 11.9 MGD. Of these average flows, only about 4.5 MGD
is sanitary sewage. The remainder is estimated to be storm
water and backwater from Sandusky Bay.
The baywater from Sandusky Bay is a problem which was tackled
by the city in 1969. A total of 25 outfalls exist in the
combined sewer collection system. Some of the storm over-
flow structures incorporating leaping weir devices have ele-
vation below the abnormally high bay levels. In the summer
of 1969, nine of the worst outfalls had new headwalls con-
structed and tide gates installed to prevent this backflow.
Eight of these installations were in operation by July 31,
1969. Average daily flow at the Water Pollution Control
Station dropped from 20.8 MGD for June to 10.0 MGD for July
and 7.G MGD for August. Figure 2 shows the location of the
25 outfalls and the location of the new tide gates.
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SANDUSKY BAY
OUTFALLS WITH
NEW TIDE GATES-
PILOT FACILITY-
r
COMBINED SEWER OUTFALLS
SANDUSKY, OHIO
KARL R. ROHRER ASSOCIATES , INC.
AKRON .OHIO
FIGURE 2
15
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The present sewage collection system contained 110.74 miles
of sewers in 1968. About 53.6 miles of the system is com-
prised of combined sewers.
Presently, any additional areas added to the collection sys-
tem are sewered with separate storm and sanitary sewers.
However, the older sections of the city have combined sewers.
A total of 24 individual combined sewer districts with 25
outfalls exist. Combined sewer districts serve approximately
2,205 acres of the total of 5,863 acres of City land area.
Much has been said about the pollution of Lake Erie. Sandusky
Bay has felt the effects of the municipal sewage treatment
plant effluent which flows to the Sandusky River and to the
Sandusky Bay. Sludge deposits have built up which are pol-
luted with a high organic content.
With municipalities going to secondary treatment along the
Sandusky River and Sandusky Bay, reduction of the sludge
deposits and subsequent pollution should result. In August,
1968, the report from the F.W.P.C.A., Great Lakes Region Of-
fice, "Lake Erie Report-A Plan for Water Pollution Control,"
states that Sandusky Bay is enriched along the waterfront
of the City of Sandusky and the eastern portion of the Bay
is polluted by septic sludge, algal growth, scum, and bacter-
ia. The combined sewer overflows are considered to contri-
bute a large portion of the pollution load. It was estimated.
in this report that the pollution load from the combined sew-
ers in this area will double by the year 2020 if no further
control measures are enforced.
In 1967, 600,000 cubic yards of dredgings were removed from
Sandusky Bay to keep the harbor open. The controversial
dumping of this material in Lake Erie has been condemned by
the F.W.P.C.A., Great Lakes Region Office, due to the pol-
lution load exerted on Lake Erie.
The Ohio Water Pollution Control Board has set water quality
standards for Lake Erie which include Sandusky Bay and for
the Sandusky River. These water quality standards are in-
cluded in the Appendix, page 145. Further increases in water
quality standards are expected to be enacted in the future.
Hearings were conducted on February 25, 1970 by the Ohio
Water Pollution Control Board on upgrading general water
quality standards now in effect in the areas of pH, D.O.,
temperature, and coliform count, which would upgrade the
Sandusky River Standards.
16
-------
Sandusky Bay
Sandusky Bay is located on the southwestern shore of Lake
Erie. The bya entrance is approximately 50 miles westerly
from the Cleveland harbor entrance. The bay entrance is
formed by and the Bay is protected by Cedar Point on the
east and Point Marblehead on the west. Figure 3 shows the
Bay area.
Sandusky Bay has a surface area of about 22.5 square miles.
The Bay is about 16 miles long from the mouth of the Sandusky
River to the Bay entrance. The Bay is broken into two sec-
tions by State Route 2 which crosses at the narrowest point.
The Bay width varies from about 5.6 miles to 1.2 miles. '
Sandusky Harbor is kept open by dredging the channel from
Lake Erie through the Bay to the waterfront at Sandusky,
Ohio. The harbor channel and turning basin have been ori-
ginally excavated through bedrock.
The water depth in Sandusky Bay when referenced to the low
water datum, 568.6 feet, varies from about nine to two feet
over most of the bay except in the shipping channel and
turning basin.
Water currents exist in the bay during periods of rising and
falling waters. However, at the site of the underwater stor-
age system these currents are negligible. Littoral dirft
due to wave action does occur.
Sandusky Bay freezes over each winter. In preliminary
investigations, it was determined that the ice along the
underwater storage tank area does not normally pile up along
the shore as it does along other sections of Lake Erie shore-
line. No piling up of ice occurred in 1967, 1968, or 1969.
The physical shape of Sandusky Bay yields fetch distances
of about 3.2 miles to 1.2 miles for wind generation of
waves for winds from Northwest to Northeast for design of
the underwater storage tanks. However, the shallowness of
the bay limits the size of waves which can be generated by
the winds. Water depth in the bay limits the design wave
choice for the underwater tank design.
Sandusky Bay Level
Data studied showed that strong winds produce abnormal
water level fluctuations in Sandusky Bay- This fluctuation
is due to the shallow bay conditions. A high water eleva-
tion of 574.1 in 1952 and a low water elevation of 566.9
17
-------
00
LAKE ERIE
POINT MARBLEHEAD
CEDAR POINT
3 4
MILES
678
SANDUSKY BAY
-------
in 1942 were recorded at Battery Park. Cleveland records
are 572.74 in 1952 and 567.5 in 1936 for the same record
levels.
The City of Sandusky takes daily readings of the bay level
at Battery Park. This data is available from 1940 to pre-
sent date and was secured to provide the required informa-
tion for design. The City of Sandusky has determined a
statistical curve for the Lake Erie water level based on
mean monthly level for 1860 to 1959. This statistical
curve is presented in Figure 4-A. However, comparison of
Marblehead and Cleveland, Ohio daily records for the level
of Lake Erie with Battery Park records for Sandusky Bay
show that while the water levels agree as to the trends,
the actual water levels may vary by two feet.
Preliminary studies for the underwater storage system
began early in 1967. Final design was completed during
1968 and construction began in July of 1968. Figures
4-B and 4-C show Lake Erie projected water levels for the
next six months for January 1967; June, 1967; December,
1969- and the actual levels from January, 1967 to January,
1970 respectively. Projected levels of the Great Lakes
are published by the Department of the Army, Lake Survey
District, Corps of Engineers' "Monthly Bulletin of Lake
Levels." Montyly lake levels are shown along with pro-
jected probable lake levels for the next six month period.
The high lake levels encountered in 1969 are even more
unusual when the record low water levels which occurred
in 1965 are considered. In only five years, the level of
Lake Erie went from record low levels to record high levels,
The normal high-low water level cycle is usually twice this
length.
Climatic Conditions
The climate of the Sandusky, Ohio area is influenced some-
what by Lake Erie. Winters are moderately cold; summers
are mild and pleasant. Periods of extreme hot and cold
weather are of relatively short duration. Differences in
elevation are insufficient to cause marked variations with-
in the area. Table 4 gives the normals, means, and extremes
for the Sandusky WB Station.
19
-------
NJ
O
FEE
MTER
3J-
ms;m
iS.SmiHi
nmsiis
sn
KEY LEVELS
LAKE ERIE LEVELS
FIGURE 4C
AVERAOE FOHOD OF RECORD
AVERASE LAST TEN YEARS
LAKE ERIE PROJECTED LEVELS
FIGURE 4 B
l KARL K. RCNRER ASSOCIATES , INC.
&' AKRON , OHIO
0.1 0.2 I
e 10 to so 40 so
0.2 It 5 K> 10 30 40 BO
PERCENT OF TIME MTER LEVEL II
AT OR ABOVE ELEVATION
LAKE ERIE WATER LEVEL
ASED ON MEAN MONTHLY LEVEL
Y CllV°OFTH%M«S^,OHIO
FIGURE 4A
FWURE I 1 C ARE IASCD ON THE
"MONTHLY IUU.CTIN OF LAKE LEVELS*
OEHMTMCNT OF THE ARMY. LAKE
SURVEY DISTRICT, CORPS. oV INSMUM
FIGURE 4
-------
TABLE 4
SANDUSKY, OHIO
Normals, Means, and Extremes
Temperature
Normal
Extremes
H
H .H -P
H X -H Pi G
(0 nj (0 -H O
PS Q g g
January
February
March
April
May
June
July
August
September
October
November
December
Annual
Years of
Record
35.7
36.4
45.2
56.3
68.3
79.0
83.7
81.7
75.4
63.5
49.2
37.6
59.3
80
21.8
22.4
29.8
39.4
50.2
60.7
60.7
63.9
57.5
46.5
35.2
25.3
43.2
80
27.5
28.1
36.6
47.3
59.2
69.2
69.2
72.3
66.0
54.4
41.7
31.3
50.7
83
rG >H M
tji cc "$. rt
H (0 O <0
ffi >H hJ JH
73
72
85
90
93
104
105
105
99
93
82
70
105
80
1950
1944
1910
1942
1941
1934
1936
1918
1953
1953
1950
1899
July
1936
__ ^ V ^
-16
-15
- 3
14
32
40
50
45
34
22
0
-13
-16
80
1879
1899
1885
1923
1923
1894
1918
1946
1956
1925
1880
1880
Jan.
1879
* ^ ^ *
\j '
-H 0
>i -H -P
r~4 ""O tJ U
Pi M CD > 0)
td J3 Q) (U S-l
0) O di M -H
S ffi W
10.8
10.9
11.3
10.6
9.0
8.1
7.6
7.6
8.4
9.3
10.9
10.6
9.6
80
CM P
SW
sw
sw
sw
sw
sw
sw
sw
sw
sw
sw
sw
sw
80
WIND
-------
TABLE 4
SANDUSKY, OHIO
Normals, Means, and Extremes
Total Precipitation
Snow & Sleet
January
February
March
April
May
June
.Til 1 v
w ui j. y
August
September
October
November
December
\nnual
fears of
lecord
(0
e
M
O
2
2.28
2.21
2.77
2.81
3.33
3.79
3 48
*J * t>
3 20
J * Ai W
2 77
A* / /
2.36
2.32
2.19
33.41
83
!>*
5
C X
O (0
a a
6.58
8.53
8.69
6.24
9.04
12.51
9 71
J 9 1 J-
8 02
(J v/ **
7 72
/ / A«
6.22
6.43
6.27
12.51
81
^
n5
Q)
1937
1887
1913
1910
1943
1937
1 Q A "3
-L y ft <3
1 RR?
_L O O At
T Q C A
1917
1927
1881
June
1937
^i
r~j
5
c c
O-H
22
0.60
0.27
0.28
0.35
0.64
0.91
09K
. ^D
n 9 "^
u . ^ o
07-3
. / o
0.43
0.09
0.63
0.09
81
M
(0
1902
1920
1910
1915
1934
1919
T Q 1 C
±7 J.O
1 RQ4
j. o y **
1 Q9R
x ./ /« o
1897
1904
1934
Nov.
1904
C rt
0) O
2 EH
8.3
6.6
4.5
1.2
T
T
T
1.8
6.0
28.4
77
^i
rH
P
C X
O -)
nj O
-p e
H
Qj J^
H 0
O
Q^ s
ti _j
PM 0
14
12
13
12
13
11
i n
-LU
q
10
12
13
38
81
-P CD
CO M
0) O
H g
CO
M
i« O
0 0
y
W H
4
3
2
0
0
0
n
\j
0
1
3
13
66
M
0
p
en
M
0)
C
^
^
0
0
2
3
5
7
7
/
c
w
o
1
1
0
34
74
Mean. No. of Days
NJ
-------
The normal annual precipitation for the Sandusky area is
34.01 inches for periods of record of 1931 to 1960. For the
83 years of record, the normal annual precipitation is 33.41
inches. Monthly normals vary from a minimum of 2.19 inches
in December to a maximum of 3.79 inches in June. The annual
mean temperature is 50.7° Fahrenheit. January is the coldest
month with a mean temperature of 27.5° and August is the warm-
est with a mean temperature of 72.3°.
Prevailing winds are from the southwest and winds exceeding
50 M.P.H. are uncommon. High relative humidity exists
throughout the year but the atmosphere is usually not uncom-
fortable.
Precipitation
A recording rain gage was set up in the drainage area on
March 27, 1967. The rain gage was moved to the control
building of the pilot demonstration facility on October 18,
1968 to facilitate operation. The rain gage installed in-
corporated a mechanical weighing mechanism with a bucket
reservoir. A twelve-hour continuous recording chart was
changed weekly or after each storm event. From March 27,
1967 to November 5, 1969, the rain gage was out of operation
for about thirty days total.
The data recorded during the period of operation from Nov-
ember 5, 1969 is summarized in Table 5. Monthly totals
of rainfall are given with comparison to normal monthly
totals for the 1931 to 1960 period and also to the normal
monthly totals for the 1921 to 1950 period for the Sandusky
WB Station. Also given are the number of days in which
rainfall exceeded 0.01, 0.10, and 0.25 inch.
Table 6 lists the storms which had sufficient rainfall to
produce storm overflow from the McEwen Street outfall along
with all storm events producing total rainfall or intensi-
ties which might produce storm overflow under other conditions
Those storms producing storm overflow caught during the one
year of operation are included in Table 9, "Tank Storage
Data."
Intensity - duration - frequency curves are included in
Figure 5. They are based from excessive short duration
rainfall from Sandusky WB Station data. Curves for recur-
rance intervals of 1,2,5, and 10 years for durations of 5
to 180 minutes are included.
State Climatologist, Mr. Marvin E. Miller, has studied
precipitation probabilities for selected locations in Ohio.
23
-------
TABLE 5
Precipitation
Sandusky Pilot Facility
Foot of McEwen Street
Sandusky, Ohio
Year of Operation
Date
5 Nov. - 30 Nov., 1968
Dec. 1968
Jan., 1969
February
March
April
May
June
July
August
September
October
Nov. 1 to Nov. 5, 1969
*Noveraber
Total
2.94*
3.02
3.83
0.37
1.69
3.23
3.83
4.46
8.21
0.81
2.96
1.99
0.15*
3.09
37.49
Normal for Month
|
1931-1960 1 1921-1950
Rainfall In Inches
2.06
2.40
2.09
2.84
3.15
3.5-2
4.10
3.53
3.27
2.77
2.05
2.23
34.01
_
2.16
2.29
1.92
2.89
2.96
3.32
3.73
3.43
2.81
3.26
2.10
2.27
33.16
Inches
0.01
0.10
0.25
Inches
0.01
0.10
0.25
Nov.
5-30
15
11
7
1969
June
17
13
5
1968
Dec.
11
5
2
July
10
6
2
1969
Jan.
12
6
4
Aug.
4
2
2
Feb.
2
2
0
Sept.
10
6
5
Mar.
6
3
2
Oct.
9
6
1
Apr.
14
10
5
Nov.
o
0
0
May
10
7
4
Total
147
77
39
24
-------
TABLE 6
STORM EVENTS
Sandusky Pilot Facility
Sandusky, Ohio
November 5, 1968 to November 5, 1969
Storm
Overflow
Produced
1.
2.
3.
Date
1968
Nov.
15
28
Dec.
27 & 28
1969
Jan.
18
28 to
30
Feb.
March
24
April
1
18 & 19
May
7
10 & 11
17
Precipitation
(Inches)
0.65
0.59
1.84
0.82
2.07
0.59
0.53
1.80
0.29
0.89
0.24
Average
Intensity
(In/Hr.)
0.08
0.17
0.15
0.08
0.06
0.06
0.07
0.12
1.74
0.09
0.24
Comments
Rainfall; No
Overflow
Rainfall; No
Overflow
Rainfall
Rainfall; No
Overflow
Rainfall; No
Overflow
No Overflow
No Overflow
No Overflow
No Overflow
No Overflow
25
-------
TABLE 6
STORM EVENTS
Sandusky Pilot Facility
Sandusky, Ohio
November 5, 1968 to November 5, 1969
Storm
Overflow
Produced
4.
5.
6.
7.
8.
9.
10.
11.**
12.
Date
18
June
1
2
14
15
19
22
23
July
4 & 5
17
Aug .
17
Sept.
6
16 & 17
Oct.
31
Precipitation
(Inches)
1.68
0.32
0.60
0.24
0.82
1.25
0.24
0.41
5.57
1.61
0.50
0.74
1.36
0.84
Average
Intensity
(In/Hr.)
0.17
0.96
0.15
0.12
0.08
0.83
0.24
0.70
0.59
0.33
0.74
0.19
0.80
Comments
No Overflow
No Overflow
No Overflow
Severe Flooding
No Overflow
Slight Overflow
No Overflow
Each storm event listed is considered a separate event
only if 12 hours separate it from a prior rainfall.
** Theoretical Overflow - Data acquisition prevented due to
malfunctioning of flowmeters. Insufficient flow for storage,
26
-------
Data contained in Research Bulletin 1017, "Monthly and
Annual Precipitation Probabilities for Selected Locations
in Ohio," by Mr. Miller and Mr. G.R. Weaver published in
March, 1969 by the Ohio Agricultural Research and Develop-
ment Center has been incorporated in Figures 6 and 7.
Figure 6, "Monthly Precipitation Probabilities for Sandusky,
Ohio," and Figure 7, "Yearly Precipitation Probabilities for
Sandusky, Ohio" are based on Sandusky WB data from 1936 to
1965. The data was prepared using a computer program util-
izing the incomplete gamma distribution to calculate preci-
pitation amounts for the selected probability levels.
Further work by Mr. Miller, as yet unpublished, is incor-
porated in Figure 8, "Monthly Maximum Daily Precipitation
for Return Periods in Years for Sandusky, Ohio," and Figure
9 "Annual Maximum Daily Precipitation for Return Periods in
Years for Sandusky, Ohio."
Drainage Area
The McEwen Street, Sandusky, Ohio combined sewer drainage
area selected for the pilot demonstration facility is lo-
cated east of the main business district. The total drainage
area is shown in Figure 10. It has an area of 14.86 acres.
Figure 11 is an aerial photograph of the area taken on May
3, 1967.
The drainage area is mainly an older residential section.
One commercial establishment, a restaurant, is in the drain-
age area. A public elementary school is located on the
southeastern edge of the drainage area but all sanitary
sewage is pumped to the Arthur Street drainage area along
with storm water from roof drains and the parking lot.
Sanitary sewage is collected from 77 separate structures.
There are 82 dwelling units in the 76 residential structures.
According to a housing studies report completed by the Erie
Regional Planning Commission in March, 1965, for the City of
Sandusky, the external condition of the residental struc-
tures in the blocks containing the drainage area are rated:
good, 61%; fair, 32%; poor, 5%; critical, 2%. Five older
residences have been converted to multiple dwelling units.
Four of these have two dwelling units and one has three.
The McEwen Street drainage area sewerage consists of vitri-
fied clay pipe 6 to 12 inches in diameter draining to the
30-inch brick sewer in McEwen Street and First Street.
Figure 12 shows the combined sewers and manhole inverts in
the McEwen Street drainage area.
27
-------
00
9 10 IS 2O SO
1 KML R. ROHRER ASSOCIATES , INC.
AKRON, OHIO
0 IOO
DURATION IN MINUTES
INTENSITY-DURATION- FREQUENCY
(EXCESSIVE SHORT DURATION RAINFALL)
SANDUSKY, OHIO 19431964
FIGURE 5
-------
2
i
I B ! I M 4 1
gz
Is
il
!=
OH m
|£
a. u
I
MONTHLY PRECIPITATION PROBABILITIES
SANDUSKY, OHIO
KARL R. ROHRER ASSOCIATES , INC.
AKRON, OHIO
FIGURE 6
29
-------
45
40
35
CO
«
O 30
- 25
_i
oe
15
10
t
5 10
20
30
40 50 60 70 80 9095
PROBABILITY OF RECEIVING EQUAL OR
GREATER THAN GIVEN RAINFALL IN PERCENT
YEARLY PRECIPITATION PROBABILITY
SANDUSKY, OHIO
KARL R. RQHRER ASSOCIATES . INC.
AKRON, OHIO
FIGURE 7
30
-------
U
O
u
oe
c
i
1 B I I 1 1
I B § I 8
MONTHLY MAXIMUM DAILY PRECIPITATION
SANDUSKY, OHIO
KARL R. RQHRER ASSOCIATES , INC.
AKRON, OHIO
FIGURE 8
31
-------
2 5 IO
25 50
RECURRENCE INTERVAL IN YEARS
100
ANNUAL MAXIMUM DAILY PRECIPITATION
SANDUSKY, OHIO
KARL R. ROHRER ASSOCIATES , INC.
AKRON , OHIO
FIGURE 9
32
-------
Nf
11 "=n i ir
McEWEN STREET DRAINAGE AREA
I KARL K. ROHRER *UOCI*TCt INC.
AKWMI.OMIO
FIGURE 10
33
-------
ill
McEwen Street Drainage Area
Figure 11
34
-------
COMBINED SEWERS
McEWEN STREET DRAINAGE AREA
" ROHRER ASSOCIATES INC.
AKRON,OHIO
FIGURE 12
35
-------
The combined sewer collection system can handle existing
dry-weather flow but is badly undersized for even moderate
storm events due to the flat slopes in the drainage area
and the capacity of the 6-inch vitrified clay sewers.
The soil in the drainage area consists of a Lacustrine
silty clay loam with a moderately slow rate of permeability.
Many trees line the streets in the drainage area.
The curb inlets to the combined sewer system are located
on paved streets. Alleys between Ogontz and Ontario Streets
are unpaved. Due to the low soil permeability and negligi-
ble ground slope, storm water does not drain freely but backs
up in yards of residents.
During preliminary investigations, the amount of runoff
from the McEwen Street drainage area was studied. A
weighted runoff coefficient was determined to be about
0.42. The original design storm, a one year storm of
60 minute duration, with a 1.30 in/hr estimated intensity
yielded a total of 220,000 gallons of runoff. However,
due to the flat slopes, the undersized 6-inch sewers, the
surface depression storage and the relatively large amount
of vegetation, a lower runoff coefficient would be more
probable for the design storm. Checks of the runoff
coefficient for the McEwen Street drainage area during the
operation period were not successful due to the poor oper-
ation of the flowmeters at the pilot facility. Data to
construct curves showing the pollution control of the
pilot facility to intensity - duration - frequency of storm
events and the pollution control to frequencies of storm
water overflow peaks and volumes was not acquired for this
same reason.
McEwen Street Regulator - Outfall
The Me Ewen Street 30-inch brick sewer brings flows from the
McEwen Street drainage area to the regulator - overflow de-
vice at the foot of McEwen Street. The regulator consists
of an adjustable leaping weir in an underground concrete
chamber with a second underground chamber accepting flow
dropping through the weir and diverting it to the intercep-
tor sewer. Any flow leaping the weir passes through a 30-
inch reinforced concrete outfall conduit to an outfall at
the shore of Sandusky Bay.
A non-sealing gate was positioned over this outfall shown
on Figure 13, to prevent debris from being washed back
into the outfall conduit. No effort was made to prevent
bay water from flowing into the outfall.
36
-------
Theoretically the overflow water passed to the end of the
30-inch outfall pipe where a drop inlet to a 12-inch corru-
gated steel pipe would carry the overflow about 250 feet out
into the bay. The drop inlet structure was completely filled
with grit.
McEwen Street
Outfall
Figure 13
The McEwen Street leaping weir had a theoretical intercep-
tion ratio of 91 prior to May 20, 1969, when it had an open-
ing width of six inches. To increase the frequency of storm
overflow from the McEwen Street drainage area during the year
of operation, the leaping weir was closed to a two-inch width
with a corresponding theoretical interception ratio of about
12.5 in May, 1969.
The high interception ratio is misleading due to the small
drainage area of 14.86 acres which is tributary to the
McEwen Street regulator. The average dry-weather flow is
only 0.026 cfs. Wet-weather flow required to result in
overflow to storage was 2.36 cfs. prior to May 20, 1969
and 0.33 cfs. afterwards. Capacity of the McEwen Street
30 inch diameter brick combined sewer is about 19.5 cfs.
maximum.
Bedrock Elevation
From conversations with city employees supervising in the
construction of the present interceptor sewer to the treat-
ment plant, a problem of location of bedrock had been
37
-------
established; however, bedrock had not been encountered at
the McEwen Street outfall during that construction. Inter-
ceptor invert is about 569.2 at this point. Proposed tank
bottom elevation was to be about 562.9.
Boring reports were acquired from the Farrell-Cheek Steel
Company dated April, 1964. Three test holes had been bored
by Herron Testing Laboratories, Inc., Cleveland, Ohio for
a plant expansion about 360 feet east of the McEwen Street
outfall. Bedrock was encountered consistently at 20 feet
below the surface elevation of approximately 582. This
showed that bedrock elevations might begin at 562 which
would be below the designed tank bottom elevations by about
one foot.
During preliminary site investigations conducted under F.W.
P.C.A. Contract No. 14-12-25, requests were made by Rohrer
to obtain 'test borings at the anticipated location of the
proposed underwater storage tanks. These requests were
turned down by the F.W.P.C.A. until after the F.W.P.C.A.
Contract No. 14-12-143 was negotiated.
After F.W.P.C.A. Contract No. 14-12-143 was in effect, six
test holes were drilled by Herron Testing Laboratories, Inc.
on January 19,20, and 24, 1968. The test holes were loca-
ted at the preliminary tank location as shown on Figure 14.
Bay water sounding showed that water depth increased with
the distance from shore to approximately 5 feet at 500 feet
north of McEwen Street Outfall.
The test holes were drilled through 12 to 18 inches of ice
on the bay. Test holes 1, 3, 4 and 5 were driven to re-
fusal. Test holes 2 and 6 were drilled five feet into the
limestone bedrock. The results of these test borings in
locating the bedrock and the unconfirmed compressive
strength of the grey limestone is given in Table 7.
The higher bedrock elevation encountered required that
further investigations be conducted at two alternate tank
locations. The rock excavation required to deepend the pri-
mary tank location to sufficient depth would have increased
system costs excessively due to the wet installation methods
that would have had to be used.
Rohrer conducted test boring to help determine the two alter-
nate tank locations using a portable drilling kit. A total
of six test borings were made on February 14 and 15, 1968.
38
-------
SANDUSKY BAY
565
566
!i75 BEDROCK
CONTOURS
R. RQHRER ASSOCIATES INC.
AKRON, OHIO
SUBSURFACE BORING
LOCATIONS
FIGURE 14
39
-------
TABLE 7
Test Borings
Hole
No. Date Depth of Refusal Bedrock Elevation
Preliminary
1
2
3
4
5
6
1A
2A
3A
4A
5A
6A
7A
8A
9A
10A
11A
12A
Hole
2
2
6
6
1-19-68
1-20-68
1-19-68
1-24-68
1-24-68
1-19-68
3-4-68
3-4-68
3-4-68
3-4-68
3-4-68
3-4-68
3-4-68
3-4-68
3-1-68
3-1-68
3-1-68
3-1-68
Unconfined
No. Date Drilled
1-20-68
1-20-68
1-19-68
1-19-68
5' - 0"
6' - 0" (Weathered
to 11' - 0")
6' - 0"
6' - 6"
5' - 0"
5' - 10"
Alternate A
7' - 3"
61 - 2"
8' - 2"
5' - 4"
7' - 3"
5' - 6"
Alternate B
6' - 6"
5' - 6"
6' - 8"
71 _ !-
3' - 5"
6J - 10"
Compressive Strength
Date Tested Depth
1-23-68 7' - 0"
1-23-68 13' - 0"
1-23-68 6' - 0"
1-23-68 10' - 0"
569.5
568.6 @ ll'-O"
568.5
568.0
569.5
568.7
567.2
568.3
566.3
569.2
567.2
569.0
568.0
568.8
567.8
567.4
571.1
567.7
,|
<\
Unconfined
Compressive
Strength"
(Ton/Sq. Ft.)
865.9
830.9
865.9
580.5
40
-------
The results showed that bedrock elevations were encountered
at 566.3 feet 600 feet north of the McEwen Street outfall
headwall and at about 564.0 feet 50 feet north. Alternate
A location showed bedrock at about 566.3 and alternate B
at 566.1.
On March 1 and 4, 1968, Herron Testings Laboratories, Inc.
bored twelve additional test holes. See Figure 14. The
results are shown on Table 7.
From the March, 1968 borings, the alternate tank location
A was chosen. The choice was based on lowest bedrock ele-
vations, ease in construction, and ability to get the re-
quired permits for construction.
41
-------
SECTION V
SYSTEM DESIGN
The system proposed to the F.W.P.C.A. for underwater storage
of storm overflow from a combined sewer by Rohrer consisted
of three basic system components, the underwater storage
tank with its associated piping and controls, a connecting
structure to the existing outfall, and a control building
to house instrumentation and pump system. With receipt of
the contract for the development of the preliminary design
for the underwater storage system on December 27, 1966,
several general system goals were set. These consisted of:
1. Gravity fill with fully automatic operation,
2. Minimum pre-treatment of overflow preceeding the
storage tank,
3. Standard construction and system installation,
4. Minimum maintenance and operator requirements, and
5. Minimum operation cost and lowest possible capital
costs.
Analysis of the storage system and the environment in which
it was to work pointed out several inherent problems.
In general, these were:
1. Continuous monitoring of tank volume at all times.
2. Control and prediction of tank shape while filling in
the underwater environment.
3. Material selection and best tank shape.
4. Control of undissolved solids and removal from tank
with minimum pretreatment prior to tank, and
5. Control of entrained and evolved gases in stored liquid.
General design parameters were controlled by the system it-
self, an underwater storage system for the off-shore tempor-
ary storage of storm overflow from a combined sewer in
flexible tanks, the chemical and physical properties of the
liquid to be stored, and the physical restraints of the site,
The site selected had several design limiting factors. The
water body, Sandusky Bay, is shallow, there is bedrock near
the surface of the bay bottom, little hydraulic head is
available to allow the necessary gravity fill of the tanks,
and no restriction of overflow could be tolerated due to
flat gradients in the sewer collection system in the drain-
age area.
43
-------
Model Studies
Included in the proposal to the F.W.P.C.A was laboratory
testing of tank models and model tank components to assist
in providing a practical tank design consistent with design
parameters and to provide the best practical solution to
inherent system problems.
The laboratory testing of the models produced practical
solutions for:
1. Tank shape,
2. Removal and control of undissolved solids in the
stored liquid, and
3. Control of evolved and entrained gases.
During February and March, 1967, the equipment necessary
for hydraulic testing was installed at the Rohrer facilities,
This consisted of:
1. A 32 foot by 16 foot by 3.5 foot vinyl lined test
tank with a work platform at one end and a movable
bridge spanning the test tank,
2. A 625 gallon supply tank to provide water to model
tanks at varying hydraulic heads,
3. A device to measure the static hydraulic head
imposed, and
4. Two centrifugal pumps and one high pressure pump
with the necessary fittings and PVC pipe as required.
Storage Tank Evolution
The liquid to be stored in the facility was combined sewer
overflow. The total tank storage capacity was limited by
the F.W.P.C.A. to approximately 200,000 gallons. From pre-
liminary design figures, this volume would intercept all
runoff from the McEwen Street drainage area for a one-year
storm of sixty minute duration.
The first area to be determined was the best general tank
shape. Originally proposed, the storage tank would incor-
porate a "pillow" type storage tank made of compatible
materials; and, a supporting structure would be designed
for this "pillow" type tank.
The "pillow" type tank as the basic component of the stor-
age tank allows one of the most economical approaches for
tank costs. These "pillow" type tanks are commercially
available "off-the-shelf" items available from rubber orient-
ed companies.
44
-------
However, since the liquid to be stored has a specific grav-
ity equal to the liquid into which the tank is to be immersed,
a problem exists in controlling the tank shape and predict-
ing this shape. From model studies conducted, the "pillow"
type tank tends to take a cylindrical shape when filled and
no particular shape on filling and emptying in its underwater
environment. The liquid could not be pumped out. When the
stored liquid near the effluent port was removed, the efflu-
ent port became clogged with the flexible tank membrane.
Since no difference between the two liquid densities exists,
buoyancy forces could not be used for effective stored liquid
removal as is done in the underwater storage of oil and cer-
tain other products.
A support system required for the "pillow" type tank also
creates considerable wearing of the tank membrane where
wave action exists. Since an extensive support system of
webbing would be required to hold the "pillow" type tank in
the shape desired, an alternative tank shape was desirable.
Testing of the "pillow" type tank also showed that removal
of entrained or evolved gases in this tank would be diffi-
cult. The support structure of nylon webbing would provide
a general tank shape but would not allow removal of gases
from one common point. An extensive number of gas vents
would be necessary.
The ability to predict tank shape was considered to be nec-
essary, since continuous monitoring of tank volume could be
most easily related to tank height, internal tank pressure,
or some other tank parameter.
One last problem presented itself from the model tests con-
ducted. This was, that in a shallow water condition with
wave action, the resonant frequency of a filled or partially
filled tank might possibly be equalled with the rectangular
"pillow" type tank. Fabric stress could then be exceeded
and tank failure could result.
After testing the "pillow" type tank model, three separate
models of a subsequent design were tested. This tank design
consisted of a steel pipe frame in the form of a modified
octagon with a flexible membrane top and bottom. The tank
top was to conform to the bottom contours when empty and
the top would rise on filling. The anchoring of the tank
would be accomplished by use of the steel frame and the
membranes would be clamped to the frame for the tank top
and bottom.
45
-------
General studies were conducted on the different models of
the "pillow" type tank and the second general tank design
to determine what reduction of flow would occur in the in-
fluent pipe to the tank as compared to that of a pipe with
no tank on the end. Dr. Andrew Simon, Head of the Department
of Civil Engineering at the University of Akron , was con-
sulted on this above comparison as well as other questions
in the model studies. From the experiments conducted, Dr.
Simon derived a percentage reduction in flow which would
be expected to occur in the prototype tank. The Appendix
contains Dr. Simon's general report on this study. Due to
the small percentage reduction in flow for the flexible
underwater tanks, this reduction could be considered neg-
ligible for the flows expected to be encountered.
The site conditions of shallow water suggested the use of
the second tank design tested due to its lower profile.
A low tank profile requires a low internal tank pressure to
keep stresses in the top and bottom tank membranes from
becoming excessive. A pressure relief valve to prevent
excessive internal tank pressures solved this problem.
Flexible Membrane
After a comparison study of the materials available to con-
struct the flexible tank top and bottom membranes was com-
pleted, a two-ply neoprene rubber coated nylon fabric was
selected for the tank membrane due to the underwater environ-
ment, the type of liquid to be stored, and the fabric
strength requirements. The Appendix contains a description
of the chemical and physical properties of the membrane.
From the laboratory testing done, the use of a rigid bottom
was suggested. If a rubber top and bottom were used, sediment
filling the tank might cause the bottom to fail if no support
were given to it. But even more important to the tank de-
sign, the bottom membrane in the model tests tended to come
up to meet the tank top. As stated before, the tank top was
designed to fit the tank bottom contours when empty. It was
decided to use two 100,000 gallon tanks allowing a comparison
of a steel bottom versus a fabric bottom to find if one was
more advantageous than the other. Figure 15 is a rendering
of the steel bottom tank design.
The elongation of the fabric was of particular interest
during design. With a 6% fabric elongation being possible
within stress limitations, the additional fabric length
could add about 80,000 gallons to the 100,000 gallons design
capacity at the same cost. Figures 16, 17, 18, 19, and 20
46
-------
UNDERWATER TANK
INTERIOR SECTIONED VIEWS
COATED FABRIC
STEEL FRAME-
TANK IN FULL CONDITION tlP^-SOLIDS RESTRAINED IN DOME
"" :*
FLUSHING JETS
Underwater Tank
Figure 15
47
-------
2.4
2Z
o
x
m
g
2,0
,..
I
8 1.4
1.2
1.0
0.8
0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
TANK HEIGHT IN FEET ABOVE TANK FRAME
TANK HEIGHT ABOVE TANK FRAME
VERSUS
VOLUME (WEST TANK)
7/fl) KARL R. ROHRER ASSOCIATES , INC.
AKRON, OHIO
FIGURE 16
48
-------
I
3
O
Q.
400
350
300
go: 25°
200
150
100
50
2 4 6 8 10 12 14 16 18
TANK HEIGHT IN FEET ABOVE TANK FRAME
TANK HEIGHT ABOVE TANK FRAME
VERSUS
TENSILE FORCE IN FABRIC
(WEST TANK)
KARL R. ROHRER ASSOCIATES , INC.
AKRON, OHIO
FIGURE 17
49
-------
18
16
w 12
Q.
10
I 8
o
III
.. 6
2.0 4.0 6.0 aO 10.0 12.0 MX) 16.0 I8JO
TANK HEIGHT IN FEET ABOVE TANK FRAME
TANK HEIGHT ABOVE TANK FRAME
VERSUS
FABRIC ELONGATION (WEST TANK)
R. ROHRER ASSOCIATES, INC.
AKRON, OHIO
FIGURE (8
50
-------
2.E5
0 2 4 6 8 10 12 14 16 18
TANK HEIGHT IN FEET ABOVE TANK FRAME
TANK HEIGHT ABOVE TANK FRAME
VERSUS
INTERNAL PRESSURE (WEST TANK)
KARL R. ROHRER ASSOCIATES, INC.
AKRON, OHIO
FIGURE 19
51
-------
16
14
III
ill 12
&
z »
o
I-
d
u 6
I
4
^
/
8 I.O L2 1.4 Ij6 1.8 2.0 2.2 2.4 2jS
TANK VOLUME IN GALLONS (xfO8)
TANK VOLUME
VERSUS
FABRIC ELONGATION (WEST TANK)
KARL R. ROHRER ASSOCIATES , INC.
AKRON, OHIO
FIGURE 20
52
-------
show theoretical tank curves for the steel bottom tank in-
stalled in Sandusky, Ohio. The design capacity was based
on zero fabric elongation due to lack of experience or
knowledge of this type of installation by the manufacturer.
Working elongation of 6% can be effectively utilized until
further data is available.
For tank design contemplated, a method of attaching the
fabric to the tank frame had to be designed. Since no exist-
ing standard clamping method could be used to the strength
required and the tank design used, a new design was required.
The clamping system incorporated the use of one-inch diameter
steel studs 2 and 5/8 inch long at 12 inch center to center
spacing on the steel frame. Sections of 4[7.25 channel were
to be drilled to allow it to slip over the studs. A top
four inch by 3/8 inch steel plate was then cut to the same
length as the channel and drilled to fit over the studs. The
remainder of the clamping system consisted of one inch dia-
meter steel rod, 1 1/4 inch diameter black steel pipe, and
a top wood filler. Figure 21 shows a rendering of the clamp-
ing arrangement. Each nut was torqued to 150 foot-pounds to
develop a continuous seal.
The top steel plate was included over the channel to provide
sufficient clamp strength to develop full fabric strength
without excessive deflection. The clamping system shown was
tested by the Firestone Coated Fabrics Company in California
on July 5, 1968. Without the top plate, the clamping system
experienced excessive deflection at full material strength.
The excess fabric was wrapped back over the clamping mechan-
ism and fastened down to provide a protective barrier so the
tank fabric could not rub against exposed studs and steel
plate edges.
The clamping system allows the fabric to take any angle of
direction away from the clamp expected to be experienced in
tank operation. While the tank frame shape requires that
the material in the short sides of the tank be folded over,
no excessive wear is expected at these points due to the
low internal tank pressures and low tank profile. Figure
21 also shows the folds used for the corner attachment of
the tank fabric.
Sedimentation Chamber
The control and removal of undissolved solids from the tank
posed a difficult problem. Complicating this problem was
the desire to do as little pretreatment prior to the tank
53
-------
FABRIC CLAMKIIMb
Fabric Clamping Details
Fiaure 21
-------
as possible. At the same time, a method had to be developed
to allow free discharge from the tank without clogging of
the effluent port by the top or bottom fabric during pumping.
During model studies, several locations for influent and
effluent ports were investigated. Several protective cages
and screens were installed around the effluent port to pre-
vent shutting off of effluent flow during pumping. From
these model studies , a method was developed to solve each
problem .
A hopper type bottom was developed for the tank. A common
influent -effluent port was established in the tank bottom.
Over this influent - effluent port a sedimentation chamber
was installed.
Figure 22 shows the original sketch of the sedimentation
chamber. The major portion of the sedimentation chamber
could be constructed from a spun elliptical head commercially
available. The designed head was of 1/2 inch steel, 120
inch inside diameter, 30 inches high and had 6 inch straight
sides. Theoretical sediment control is:
1. Basic hydraulics states that for incom-
pressible flow the volumetric flow rate, Q,
is equal to the average velocity, V, of the
incompressible fluid flow times the cross-
sectional area, A, of the flow: Q=VA.
The continuity equation for incompressible
flow states that this flow rate is contin-
uous through a closed system. Therefore:
and Vl RI = V2 A2
2. The influent - effluent pipe area is known.
A velocity for the influent at the point
entering the tank can be estimated for a
given flow. If a given open area is pro-
vided through the elliptical head over the
influent-effluent port, the velocity at the
elliptical head surface can be determined.
3. Knowing what velocity exists at the ellip-
tical head surface, Figure 23 can be examined
to determine what size of particle will begin
to settle out. An optimum particle size can
55
-------
VELOCITY REDUCTION
OPENINGS
5
TO
tn
o
c
3)
m
ro
ro
EROSION VELOCITY
OPENINGS
INFLUENT-EFFLUENT
PORT
SEDIMENTATION CHAMBER
-------
t_n
SIZE OF PARTICLES IN mm
RATIO OF PARTICLE SIZE TO VELOCITY REQUIRED FOR
EROSION, TRANSPORTATION, AND DEPOSITION.
(AFTER HJULSTROM.)
HAUL «. ROHRER ASSOCUTIS.HC.
AKMON, OMO
FIGURE 23
-------
be determined and required optimum area
of velocity reduction openings can be set.
With this system operation, grit and some
lighter organic r jtter can be contained
within the sedimentation chamber.
4. A diversion cone was placed over the
influent-effluent port inside the ellip-
tical head.
5. For removal of the suspended solids in
the chamber, Figure 23 gives a required
erosion velocity. The effluent port has
a constant area. Therefore, an erosion
velocity can be produced by varying cross-
sectional area at the sedimentation chamber
perimeter; since for a given effluent flow
rate, the velocity at the effluent point
is known.
6. The area of the erosion velocity openings
can be determined and this area removed
from the periphery of the elliptical head.
7. The operation of the system is automatic
with no moving parts. The top fabric con-
forms to the tank bottom contours when
empty. Influent to the tank raises the
tank top on filling. Due to the velocity
reduction openings and the resulting in-
crease in flow area, grit and some sus-
pended organic material settle out in the
head. Suspended material not remaining in
the sedimentation chamber settles out close
to the head within the hopper bottom. When
the tank is filled, most fine material
settles out. On emptying, the solids at the
effluent port are removed immediately. The
effluent velocities are below the erosion
velocities required to remove most of the
settled solids. The tank is emptied and
the top fabric lowers to the elliptical
head. As the tank is emptied, the fabric
top closes off the velocity reduction open-
ings. Finally all velocity reduction open-
ings are closed off and the erosion velocity
openings increase the flow velocity and
resuspends settled material effectively re-
moving the major amount of solids which have
58
-------
entered the tank. The effective range of
this velocity increase is limited due to
the virtual mass displacement of liquid
which occurs. To help move the solids to-
ward the sedimentation chamber, a flushing
system was included in the tank utilizing
a high pressure flow of bay water, the pipe
frame as a manifold, and drilled openings
in the frame as nozzles to push the solids
toward the sedimentation chamber.
Any solids left in the tank after pumping
should accumulate at such a slow rate as to
tend to have a negligible effect. The top
flexible material as it lowers tends to
limit cross-sectional flow area and move
this material toward the sedimentation
chamber.
The sedimentation chamber also allows free pumping from the
tank. The sedimentation chamber is sized along with the
top fabric such that the top fabric can not close off all
open areas available for stored liquid to flow to the ef-
fluent port until the tank is empty. Some liquid will
remain within the tank but this liquid is negligible when
compared to tank capacity.
Laboratory testing showed that effective sedimentation
control could be accomplished with the sedimentation cham-
ber and only trash removal was required prior to the storage
tank.
Gas Vent Valve
The storm overflow to be stored may contain entrained gases
which will collect in the tank on filling. Evolved gases
may also collect during temporary storage of the liquid due
to the volatile organic solids which are present. While
gas accumulation rates should be minimal the build up of
gas could cause excessive buoyancy forces and excessive
fabric stress.
Since no commercially available valve was found which would
operate under the environmental conditions involved or pro-
duce the desired results, a valve was designed for the under-
water storage system. The valve design was tested in the
laboratory on a scale model and worked sufficiently well to
allow adoption for use.
59
-------
The gas vent valve required had to operate for three differ-
ent pressure possibilities:
Case I: Zero pressure differential between tank and exter-
nal environment, and
Case II: Negative pressure differential between tank and
external environment.
Case III: Positive pressure differential between tank and
external environment.
In Case I and III, the valve must allow the escape of gas
pockets within the tank without allowing the escape of liquid
from the tank. These two cases occur in the filling of the
tank and after the tank is filled. In Case II, the valve
must prevent bay water from entering the tank. This occurs
on emptying the tank. Gas expulsion is not considered
necessary at this point in tank operation.
The gas vent valve design is based on the buoyancy forces
of a submerged ball float versus the gravitational weight
of the ball float. The gas vent valve is shown in Figure
24.
During filling of the tank, there will be zero tank pres-
sure, Case I. The buoyancy of the ball float causes it
to seal against the upper seal. When an air pocket forms,
the ball float falls free and the gas passes around the
ball float until it is again submerged. With an internal
pressure, Case III, the buoyancy and internal tank pres-
sure causes the ball float to seal.
When the tank is being emptied, a negative internal pressure
is experienced, Case II. The ball float is forced to seat
against the bottom seal due to the float weight and pressure
differential. Bay water is kept out of the tank by the ball
float sealing against the bottom seat.
The density of the ball float and its subsequent submerged
weight are critical. Weighted hollow metal spheres were
used. Future ball floats could be of plastic materials.
The internal tank pressure must be kept within limits for
the gas vent valve to operate as required. However, inter-
nal tank pressure was anticipated to be 0.5 psi maximum
which allowed full gas vent valve operation.
The ball float tends to operate in a rapid piston type
motion. The ball float strength is critical due to this
severe loading.
60
-------
SCREEN
TOP LATCH
(3 PROVIDED)
NEOPRENE FABRIC
FLOATATION COLLAR
FLOATATION COLLAR
GAS VENT VALVE
NEOPRENE FABRIC
tff) KMLM. ROHRER ASSOCIATES,INC.
I? MOWN, OHIO
FIGURE 24
-------
The gas vent valves were constructed with a float collar
to allow a neutral to slightly positive buoyancy. This
tends to keep the vent valve at a high point and allows com-
plete expulsion of gas. Five gas vent valves were used on
each tank for this installation. On later installations,
only one valve should be necessary.
Pressure Relief Valve
With the low tank profile, a pressure relief valve is re-
quired for a positive method of preventing internal pressures
from exceeding allowable limits. If a low internal tank
pressure can be held, fabric strength can be reduced with a
substantial reduction in fabric cost resulting.
As a simplification of the fabric tension calculation, the
linear tension T (pounds per inch) in the fabric may be said
to equal the product of the internal pressure P (pounds per
square inch) and the radius of curvature R (inches).
T = PR
From this, it is evident that the stress in the fabric is
directly proportional to the radius of curvature, R, for
constant values of internal pressure, P.
Therefore, for a low tank profile with a high radius of
curvature, R, a higher stress results than if a higher tank
profile was allowed with an associated lower radius of
curvature.
The storm overflow to the tank is controlled by a valve in
the influent line to the tank. At a preset tank volume or
tank height, this valve is automatically closed preventing
further storm overflow from entering the tank. Valve fail-
ure would result in excess overflow filling the tank and
subsequent failure of the fabric might result. To prevent
tank failure in case of failure of the control valve, a
pressure relief valve was installed just prior to the tank
on the influent line. Figure 25 shows the pressure relief
valve installed on the west tank.
The top plate was so designed that an internal tank pressure
of 0.5 psi would lift the top plate and allow storm overflow
in excess of tank capacity to escape to the bay.
After each pressure relief valve was manufactured and the
top assembly put together, the assembly was weighed to det-
ermine if the submerged weight was within design tolerances.
62
-------
Pressure Relief Valve As
Installed on West Tank
Figure 25
Tank Level Control System (T.L.C.S.)
A system was required to continuously monitor tank volume
at all times and to operate control valves on the influent
lines to the tankt It was also desirable to continuously
record bay levels to evaluate bay level effects on the tank
system operation.
A bubbler system, Figure 26, was incorporated to yield both
tank height and bay level and to operate the tank control
valve. With the tank height determined, a plot of tank
height versus tank volume can be used to determine tank
volume; and, at a given tank height or related volume, the
control valves can be signaled to close. Figure 16 shows
a plot of tank height versus volume.
Figure 27 shows a photograph of the T.L.C.S. panel in the
operator's office as installed during the construction
phase of the project.
Connection Chamber
Some structure was required to connect the storage system to
the existing outfall. Figure 28 is a drawing of the connec-
tion chamber.
63
-------
CTi
LHJJ-^P,, LCD-^OP, jj
-/
1
4
I
^ ^
4
^
-i
I ' I
^
Q*
*c
-Q-1
r'
1 ^^
*~v
f
fR-:
k
A
I FILTER -PRESSURE REGULATOR
2. PRESSURE REGULATOR
1 SKMT FEED (UMLER
4. FISHER DIFFERENTIAL PRESSURE
TRANSMITTER
a FISHER mommoN
TRANSHITTDI
t. FISHER THREE -WAY SWITCHING
VALVE
T FISHER 12* VEE iALL AIR
OPERATED VAIVE
SYSTEM ACCOMPLISHES^
I CONTINUOUS RECORDING OF
BAY LEVEL
2. CONTINUOUS RECORDING OF
TANK TOP ELEVATION.
3. CLOSING OF INFLUENT
CONTROL VALVE AT
PRE-SET TANK HEIGHT.
TANK LEVEL CONTROL SYSTEM (T.LC.S.)
>«ARL R ROHRER ASSOCIATES INC
AKRON, OHIO
FIGURE 26
-------
Tank Level Control System (T.L.C.S.)
Figure 27
65
-------
BAR
SCREEN
WITH TRAS
PIT IN F
TIDE GATE
SAFETY OVERF
CONNECTION CHAMBER
KARL R. ROHRER ASSOCIATES , INC.
AKRON, OHIO
FIGURE 28
66
-------
The connection chamber is a reinforced concrete structure
with two separate compartments. Storm overflow entering
the first compartment is first passed through a bar screen
to remove all trash from the storm overflow. This trash
is caught in a trash pit immediately in front of the bar
screen and manually removed after each storm event. Very
little trash was anticipated due to the type of drainage
area feeding to the McEwen Street outfall. Next, the storm
overflow passed to the influent pipes to the tanks. A
diversion weir was installed to control storm overflow to
one tank or the other. After the tanks were filled, the
storm overflow was designed to flow out of the safety over-
flow provided in the connection chamber for storms in excess
of the design storm.
Due to the intensities and durations of storm events in the
Northwestern Ohio area, a design capacity to store all storm
overflow is infeasible. A contract limitation of 200,000
gallons total tank capacity for the pilot facility also re-
quired that some type of overflow be installed.
The flat gradients in the McEwen Street combined sewer system
required that minimum restriction of storm overflow be allow-
ed. If storm overflow was backed up when the tanks were
filled, or if a higher flow rate of storm overflow occurred
than the influent piping to the tanks could handle, the
residences in the lower portions of the drainage area would
experience flooding of basements. This condition could not
be tolerated.
Due to the minimal amounts of trash expected, the safety
overflow was placed downstream of the bar screen. On most
installations, this safety overflow should be upstream of
the bar screen.
The second compartment in the connection chamber housed
the influent control valves for the tanks.
Control Building and Associated Equipment
The remaining portions of the storage systems were housed in
a control building, a prefabricated metal building 20 feet by
26 feet. The interior of the control building was divided
into seven parts to house the remaining portions of the
storage system as required by system design. These sections
were:
1. Office and instrumentation control room,
2. Pump pit,
67
-------
3. Auxiliary power area,
4. Maintenance area,
5. Sample analysis area,
6. Sampler room, and
7. Washroom with shower.
The office housed a desk for the operator and all of the
recording equipment. Recorders were necessary for contin-
uous recording of dry-weather sanitry flow, storm overflow,
T.L.C.S. showing bay water elevation and tank top elevations,
and the volume of liquid pumped from the tanks. The west
wall of the office also housed the major portions of the
T.L.C.S. instrumentation and all pump controls. See Figure
27.
The northwest portion of the control building was used as a
pump pit. An eight-inch centrifugal Gorman-Rupp sewage pump
with its associated motor, magnetic flow meter for pump
effluent, and piping and valves were housed here. A worth-
ington high pressure jet pump was also located here with
its associated piping and valves to supply lake water to the
tank flushing system and to allow monthly testing of the
underwater tanks when no storm event occurred. A sampler
for taking a composite sample of pump effluent from the
tanks was also provided. Figure 29 is a photograph of the
sewage pump.
Sewage Pump
Figure 29
68
-------
The system design also required an auxiliary electric sup-
ply with automatic load transfer capabilities for a power
source during storm events in case of failure of the normal
power supply. An Onan 15.6 KVA electric generating plant
with an automatic load transfer control was included. A
propane supply tank was located outside of the control build-
ing for fuel supply to the generator.
A work bench with hand tools was installed in the maintenance
area of the control building so minor repairs could be made
at the site. The southeast corner of the control building
housed the sampler room. The air compressors for the T.L.
C.S. were also located in the sampler room.
Laboratory space was provided for sample analysis by the
operator at the site. A storage refrigerator with BOD
incubator, sink and work space, storage cabinets, drying
ovens and muffle furnace, and analytical balance were pro-
vided with the miscellaneous equipment for the analysis re-
quired.
Sampling Program
To be able to design and evaluate an underwater storage
system of the type installed, a complete sampling program
was set up. For the design of the facility, the chemical
and physical properties of both the liquid to be stored and
industrial wastes or other chemicals in the water body which
would have a deleterious effect on the storage system mater-
ials were determined. Deterioration of the system materials
must be limited to allow maximum system life, to provide
economy, and to minimize system maintenance.
To be able to evaluate the underwater storage system itself,
the pollution load intercepted, the pollution load of the
liquid after storage, and the reduction in pollution to the
receiving water body must be determined. A sampling program
was set up to provide data for evaluation of the following:
1. BOD,
2. Coliform,
3. Settleable solids,
4. Suspended solids, SS,
5. Suspended solids volatile, SSV, and
6. pH.
Sample parameters were determined for:
-------
1. Grab samples for the dry-weather flow,
2. Individual timed samples and composite samples of the
storm overflow from the combined sewer drainage area,
3. Composite samples of effluent from the storage tanks,
and
4. Grab samples of bay water at the outfall in the
surrounding bay after each storm event and as required
to provide evaluation data.
The sampling of the combined sewer storm overflow was de-
signed to be accomplished by an automatic sampler. The con-
tract required that the sampler begin taking individual
samples at the beginning of overflow and take an individual
sample at a time interval throughout the storm. A composite
sample proportional to flow was to be taken for each storm
event.
At the time of design, no sampler was commercially available
to do this job and at the same time secure a representative
composite sample. Therefore, a sampler was designed and
constructed. A schematic of the sampler used is shown in
Figure 30. Twenty-four individual sample containers of one
pint each and five gallon composite sample container was
used. The time interval for the individual samples was set
at five minutes but this time interval could be preset for
5 to 60 minutes. The composite sampler was operated from a
total flow switch which took a preset sample every 10,000
gallons of flow.
Rain and Staff Gage
In order to evaluate the storage system, a recording rain
gage was provided in the preliminary design. Prior to fac-
ility construction the rain gage was located in the south-
east corner of the drainage area. After construction of the
facility, the rain gage was relocated at the site.
A visual method of measuring bay level fluctuation was also
desirable to compare with bay level readings from the T.L.
C.S. A staff gage was installed outside of the excavated
tank area to provide visual readings of water level and
peak wave fluctuation which is not recorded by the T.L.C.S.
Design Operation
Figure 31 shows the system flow plan for filling of the
underwater tanks during a storm event.
70
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MAPMNAM PUMP
COMBINED SEWER
STORM OVEFUJW
SAMPLE
COMBINED SEWER
STORM OVERFLOW
SAMPLE
COMBINED SEWER
STORM OVERFLOW
SAMPLE
RETURN SPRING
TO INDIVIDUAL OR
COMPOSITE SAMPLE
BOTTLE
RETURN TO
SEWER
NORMAL FLOW
AUTOMATIC SAMPLER
SAMPLE AQUISITION
KARL ». ROHRER ASSOCIATES INC.
AKRON, OHIO
FIGURE 90
-------
I. LEAPING WEIR REGULATOR.
2. DWF FLOW METER.
3. STORM OVERFLOW FLOW METER.
4. TRASH PIT.
5. BAR SCREEN.
6. CONNECTION CHAMBER.
7. CONTROL VALVES.
8. PRESSURE RELIEF VALVE.
9. SEDIMENTATION CHAMBER.
IO.STORAGE TANK.
II. PIPING FOR FILLING TANKS
WITH BAY WATER FOR TESTING.
INTERCEPTOR FLOW
TO WATER POLLUTION
CONTROL STATION.
STORM EVENT FILUN6 TANKS
FLOW DIAGRAM OF UNDERWATER
STORAGE SYSTEM
R. ROHRER ASSOCIATES, INC
AKRON, OHIO
OWF
FIGURE 31
72
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Runoff from a storm event increases to the point where it
jumps the leaping weir regulator at the McEwen Street regu-
lator. Flow not jumping the weir and dry weather flow is
intercepted by the weir and is diverted to a second existing
chamber where this flow is measured by using a ball float
type stage recorder calibrated to an existing channel. After
passing through this second chamber, the flow proceeds to
the existing interceptor and to the City of Sandusky Water
Pollution Control Station for treatment.
Flow leaping the leaping weir passes through an overflow
conduit to the connection chamber. Storm overflow is mea-
sured just beyond the leaping weir by the use of a ball
float in conjunction with a fiberglass flume.
After measurement of the storm overflow, an automatic sam-
pler pumps a continuous liquid sample from the overflow.
From this continuous sample flow, individual samples are
taken on a preset time interval during the first 120 min-
utes of the storm event and a composite sample is taken
proportional to the flow. The composite sample is taken
on signal from the storm overflow flowmeter (once every
10,000 gallons). The operation of the sampler begins on
signal of flow by the storm overflow flowmeter.
The main section of the connection chamber houses the trash
pit, bar screen, safety overflow, and the influent pipes to
the underwater storage tanks. Flow passes through the bar
screen with trash falling out into the trash pit. The
trash is manually cleaned after each storm event by raking
the trash up an inclined ramp to a trash bucket located on
top of the connection chamber.
Flow proceeds to the influent pipes to the underwater stor-
age tanks. A diversion weir prior to the influent pipes
allows blocking off low flows to one tank of the operators
choice so one tank fills leaving the second tank empty un-
less total storm overflow exceeds the single tank capacity.
At higher flow rates, the diversion weir is overtopped,
and both tanks filled simultaneously.
The control valves for the influent pipes are installed in
the second connection chamber compartment, a valve pit.
The control valves remain open until the tanks are filled
to a preset volume. On reaching this volume, the T.L.C.S.
automatically closes the valves.
After tank capacity is reached and the control valve closes,
storm overflow backs up in the connection chamber until
depth is sufficient to pass out the safety overflow.
73
-------
Storm overflow which passed through the influent piping to
the underwater storage tanks first reaches the sediment-
ation control chamber over the influent port of each tank.
Most suspended material settles out within this chamber. The
storm overflow minus this suspended material continues to
the tank proper for storage.
The storm overflow is stored after each storm event until
the interceptor sewer has capacity to take the storm over-
flow to the City of Sandusky Water Pollution Control Station
for treatment. Capacity at the Water Pollution Control
Station must be available when stored sewage is returned to
the interceptor.
Entrained gas and any evolved gases from storage of the storm
overflow is removed from the underwater storage tank by
automatic gas vent valves located on each tank top.
If failure of the influent control valves occurred, a press-
ure relief valve located on the influent line to each under-
water storage tank allows all flow in excess of maximum
design tank capacity to flow to the receiving water body.
This is purely a safety feature to prevent storage tank
failure.
Figure 32 shows the system flow plan for emptying of the
underwater storage tanks after a storm event.
Emptying the underwater storage tanks can be accomplished
in about one hour per tank. Influent control valves are
closed prior to pumping if not already closed from the
storm event.
Manually operated valves are opened and the sewage pump
manually initiated. One tank is emptied at a time. Ef-
fluent from the underwater storage tanks is measured by
the use of a six-inch magnetic flowmeter positioned on
the effluent piping of the sewage pump.
Grab samples of the storm overflow from the underwater
storage tanks are taken on pumping to determine the ef-
fects of underwater storage on the pollution load of the
storm overflow.
The flushing system is operated in conjunction with the
pumping of the underwater storage tanks. A high pressure
pump pumps bay water through a water intake in the bay to
the tank pipe frame. The pipe frame acting as a manifold
directs the high pressure water through nozzles along the
74
-------
I. UNDERWATER STORAGE TANK.
2. SEDIMENTATION CHAMBER.
3. SEWAGE PUMP.
4. TANK EFFLUENT FLOW METER.
5. BAY WATER INTAKE.
6. HIGH PRESSURE PUMP.
7. FLUSHING SYSTEM USING TANK
FRAME AS MANIFOLD.
PIPING TO PUMP OUT TRASH
PIT.
9. PIPING TO PUMP OUT VALVE
PIT.
10. LEAPING WEIR.
INTERCEPTOR FLOW
TO WATER POLLUTION
CONTROL STATION
EMPTYING TANKS
FLOW DIAGRAM OF UNDERWATER
STORAGE SYSTEM
DWF
FIGURE 32
KARL R. ROHRER ASSOCIATES , INC
AKRON, OHIO
75
-------
tank bottom. This action tends to flush settled material
towards the center of the tank.
After each tank is emptied, the trash in the connection
chamber trash pit is manually raked out by the operator.
Trash is disposed of at a sanitary land fill.
The water in the trash pit is pumped out through a pipe
connecting to the sewage pump system.
The connection chamber is hosed out as required. The con-
nection chamber valve pit is pumped out through a pipe
connecting to the sewage pump system as required.
During periods when no storm event occurs of sufficient
intensity or duration to produce storm overflow, the under-
water storage tanks are tested by filling with bay water.
Bay water is pumped from a connecting pipe from the high
pressure pumping system to the connection chamber. Bay
water builds up in the connection chamber until sufficient
hydraulic head is available to fill the tank being tested.
Only one tank is to be tested at a time to provide capa-
city in the other tank to intercept any storm overflow
from a storm event.
The remainder of filling and testing of the underwater
storage tanks is conducted in the same manner as for storm
events.
Figure 33 is a plot plan of the underwater storage facility,
76
-------
»T.»' »a -i^*1
PLOT PLAN
«»HL R ROHRER 4550CHTES INC
AKKON ,OMK>
-------
SECTION VI
CONSTRUCTION
Construction procedures for the demonstration facility were
controlled by the site conditions encountered and by the
system itself. Due to the shallow water conditions in San-
dusky Bay at the foot of McEwen Street and the elevation of
bedrock in the site area, the underwater tanks were located
adjacent to the Penn Central Railroad tracks parallel to the
waterfront. This tank location required excavation into
the bedrock to obtain sufficient depth for the underwater
tanks. Tank installation was accomplished by diking in the
tank area and pumping the water out for dry construction.
On July 3, 1968, tentative approval for construction was
given by the F.W.P.C.A.; and, on July 10, 1968, Rohrer re-
ceived final authorization to begin construction of the dem-
onstration facility. The subcontract with Bay Construction,
Inc. of Sandusky, Ohio was signed and preliminary work al-
ready begun was stepped up.
A breakdown of the actual construction time for the demon-
stration facility is included in Figure 34. The breakdown
shows only that time spent for construction and installation
on the site and does not include time spent by subcontractors
for fabrication of system components. All items marked for
a given work day were worked on for at least four hours;
however, the entire work day was not necessarily spent on
each item. The number of construction workers used is not
indicated.
Site preparation consisted of preparing the material and
equipment storage area on Farrell-Cheek Steel Company pro-
perty immediately to the east of the site area. Two tem-
porary crossings were installed over the Penn Central
Company tracks for construction. The dike was surveyed and
staked so construction could begin%
Construction time was estimated at 100 days with the tank
area remaining diked-in until after the underwater portion
of the storage system was accepted by the F.W.P.C.A. During
the construction portion and while the dike was installed,
an overflow pipe from the existing combined sewer outfall
beyond the diked area had to be built. This prevented storm
overflow from flooding the diked area during construction
and also prevented storm overflow in excess of tank capacity
from filling the diked tank area while the dike remained in
place.
79
-------
00
o
KbN CONSTRUCTION FWPCA
OTC PREPARATION
NOTE'
(L)ALL DATES INCLUDE
INSTALLATION AND ON
SITE WORK ONLY.
MRICATION TIMES
NOT INCLUDED.
DIKE
INSTALLED
REMOVED
EXCAVATION
MUCK
ROCK
(1.) WEEKENDS
INDICATED AS SHOWN.
CONNECTION CHAMCER
CONTROL lULOINS
~ STRUCTURAL
CARPENTRY
_ PAJNTINS
TANK AREA REPARATION
ROCK, RE-CARS, FILL
SEDIMENT CHAMIER CONG
EAST TANK
WEST TANK
PI PINS
SEDIMENT
EAST TANK
WEST TANK
W.TK. FRAME BOTTOM
»TK.__TOP
E. TK. FRAME
E. TK. SOTTOM
E.TK
PUMPS PIPINS
CLEAN
_ VENT VALVES
INITIAL TESTINS
ACCEPTANCE IY FWPCA
CONSTRUCTION
KARL R. ROHRER ASSOCIATES , INC.
AKRON. OHIO
-------
The overflow pipe consisted of a 30-inch tar coated corru-
gated steel pipe approximately 120 feet long. A tide gate
was installed on the bayward end to prevent bay water from
flowing into the diked area.
With the tanks located near the existing outfall, an L-
shaped dike, approximately 350 feet long, was required. The
dike was constructed with sandstone and sealed with clay.
Excavation for the installation of the storage tanks was
required due to the existing shallow water conditions. Total
design tank height was seven feet for a normally filled tank.
Because three to four feet of water was needed over the tanks
for best protection, a total of ten to eleven feet of total
depth was required at the tank area. To get this depth, it
was necessary to remove sediment deposits over existing bed-
rock and remove or excavate some bedrock to achieve a bottom
tank elevation of 559.07.
Overlaying deposits of silt, clay, and sand with some loose
rock were removed from the diked area after dewatering. A
total of 3,080 cubic yards was removed and placed on up-
land property above high water level as required by the
F.W.*P.C.A. Great Lakes Office. This top material removed
had a high organic content due to the combined sewer out-
falls along the bay and the municipal treatment facilities
which use the Sandusky Bay and Sandusky River as receiving
water bodies for effluent.
Since bedrock in the vicinity of the tank area did not allow
installation without blasting, rock was excavated by blast-
ing to a depth which allowed placement of feed pipes to the
tanks and then gravel backfill was used to establish re-
quired final elevations.
Blasting of the rock was accomplished by drilling with a
rotary air drill, then placing blasting mats over the charges
in the drilled holes and over the rock to be removed. This
was required since homes were located 70 yards from the
tank area. Rock excavation depth varied from 3.8 to 5.6
feet over the entire tank area resulting in a total of
2,205 cubic yards of rock excavation.
Tank Installation
After all material was excavated, the diked area was ready
to be prepared for installation of the two tanks. Each
tank required eight anchor piles. Holes were drilled into
the bedrock and four anchor bolts were grouted into place
81
-------
for each pile. The anchor pile base plates were then
slipped over the anchor bolts, leveled at the proper
elevation, bolted down, and grouted into place.
On August 7, 1968, anchor bolts were tested to determine
if sufficient strength could be developed. Loads were
applied up to twice the design loads with no sign of
failure.
The next step in tank design was the construction of the
center concrete support for the sediment control chamber.
Upon completion of the center concrete support, the tank
area was brought up to the required elevations with gravel.
A concrete pad was then poured to fit the bottom contours
of both storage tanks. The concrete pad for the east tank
was approximately six inches below final tank elevation,
since a sand cushion was placed between the pad and the
rubber coated fabric bottom of the east tank to reduce
abrasion on the fabric.
The use of the concrete pad allows uniform support for the
tank bottoms. The support is necessary due to possible
sediment accumulation in the tank and underwater forces
exerted in the tanks. Future installations might not allow
dry construction; however, storage tank design could easily
be altered to accomodate wet installation.
The steel components were manufactured by Continental-
Fremont, Inc., in Fremont, Ohio approximately 26 miles from
the Sandusky, Ohio site. The east tank frame was manufactur-
ed in four quarter sections for shipping and installation.
The west tank frame was manufactured in four quarter sec-
tions with the 1/4 inch steel bottom plate attached. The
remaining steel plate for the bottom of the west tank was
then delivered in six sections.
One 18-ton and one 25-ton truck mounted crane with tele-
scopic boom were used to lower each quarter section into
its proper location for attachment to the anchor piles.
Each quarter section for the west tank weighed about 9,700
pounds. Each quarter section for the east tank weighed
about 5,650 pounds.
West Tank
With concrete pad, influent piping, center concrete support
structure, and anchor piles completed, the quarter sections
of the tank frame were lowered into their respective approx-
imate locations. Final placement was completed and the
82
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quarter section was welded to two anchor piles. In turn,
each quarter section was then welded together.
The six bottom sheets were then positioned and welded to-
gether. The sediment control chamber and its bottom sheet
were then lowered and bolted into position over the center
concrete structure. Bottom support was supplied by the con-
crete pad. See Figure 35 and Figure 36.
The 18-inch steel pipe tank frame was tested to insure water
tightness by filling with water for four hours at 125 psi.
Holes, three sixteenth inch in diameter were then drilled
in the frame as called for in the design of the flushing
system to aid in sedimentation removal. The bottom of the
tank was then filled with water to check the water tightness
of the west tank bottom.
The top fabric was installed next. Mr. M.M. Yancey, Techni-
cal Representative for the Firestone Coated Fabrics Company,
supervised installation of the rubber coated fabric purchas-
ed for the underwater tanks.
For the west tank, the fabric was unrolled in the tank bottom.
A minimum of seven laborers was required. The tank was then
filled with water to reduce the dead weight of the fabric
for installation. This allowed a reduction in fabric elonga-
tion during installation and a more accurate placing of the
fabric in the clamping system. The weight of each fabric
section was about 3,550 pounds.
Care must be exercised in securing an exact fabric length
between tank sides. By being only two to four inches off on
the fabric clamp line in the 56.58 foot clamp to clamp fabric
design length, a variance in excess of 10,000 gallons of tank
volume could result at zero psi internal pressure. Mark
lines for clamping the fabric had been put on by the manu-
facturer.
After clamping the fabric to the frame, the excess fabric
was pulled back over the clamp and fastened to the side of
the clamp channel. Figure 21 in Section V, is a rendering
of the clamping system used.
Five gas vent valves were installed in the top tank fabric.
A bubbler line was attached along the tank fabric from the
frame to the center gas vent valve. The exposed tank metal
was painted with an aluminum base paint.
83
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West Tank
Diversion Cone
Figure 35
West Tank
Sedimentation Chamber
Figure 36
84
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East Tank
Preliminary work was completed for the east tank in a man-
ner similar to the west tank. The east tank had a rubber
fabric top and bottom which presented some difficulty in
installation. The anchor piles were constructed four feet
longer than necessary for final tank elevation. The four
tank frame sections were lowered into their relative posi-
tions for fabric installation, welded together, and bolted
to the anchor piles four feet above final tank elevations.
A wooden platform was installed beneath the east tank frame
and the bottom tank fabric unrolled on this platform. The
fabric was then clamped to the frame and the wooden platform
removed. The frame was then unbolted from the anchor pedes-
tals and lowered to its final position.
Both sedimentation chambers for the tanks arrived two weeks
late. Therefore, the bottom fabric for the east tank was
installed prior to the installation of the sedimentation
chamber. An opening was cut in the bottom fabric to allow
the sedimentation chamber to be positioned as required.
The sedimentation chamber along with its bottom sheet was
welded to the bottom steel plate over the center concrete
structure.
The top fabric was then lowered into the tank and unrolled.
Clamping of the fabric was completed; and, after installation
of the five vent valves, bubbler tube, and painting of ex-
posed metal, the east tank was ready for preliminary test-
ing.
When the east tank was filled with water the first time, a
leak developed where the bottom fabric was fastened by the
bolt ring to the center concrete structure. The influent-
effluent pipe to the tank had been installed in a 18-inch
wide trench through the concrete pad and the space around
this pipe packed with sand. Prior to testing, the sand had
settled at the edge of the center concrete structure and
the fabric failed at the bolt ring due to the weight of the
water over it, and sand washing out of the pipe trench.
To repair the leak, the top fabric was undamped along one
side and then the bolt ring holding the bottom fabric re-
moved. The sand in the influent - effluent pipe trench to
the center concrete structure was removed from around the
pipe and replaced with grout. A steel plate was clamped to
the bottom fabric and the bolt ring tightened. The top
fabric was reclamped and the tank refilled with water.
85
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No leaks reoccurred. Figure 37 shows the two completed
underwater storage tanks in October, 1968.
Control Building
A 20 foot by 26 foot prefabricated metal building to house
the system pump, pump controls, bubbler system, and record-
ing instrumentation, sampler, and auxiliary generator arrived
at the site eight weeks after it was scheduled. This prevent-
ed system completion by the October 16, 1968 end of construc-
tion date anticipated. However, after arrival, the control
building and associated equipment was installed in time for
the rescheduled October 26, 1968 opening.
All system piping was installed as required. Twelve-inch
lines to the tanks were installed in trenches blasted in
the rock. A water intake was placed in the excavated tank
area to provide all water necessary for testing the storage
facility and to supply bay water for the high pressure
flushing system.
Construction Complaints
No complaints were registered concerning the noise or blast-
ing which accompanied drilling and rock excavation. However,
complaints were heard concerning the dirt which was deposited
on Ogontz Street during dike installation, muck excavation,
and rock removal. Also complaints concerning the heavy truck
traffic were noted.
Preliminary Testing
After completion of construction, preliminary testing was
conducted from October 17, 1968 through November 5, 1968
to determine if the underwater storage system was operating
properly and to check instrument calibration. Several
minor problems were discovered and corrected. These were:
1. Leaking check valve in connection chamber,
2. Unstable concrete pedestals for bubbler lines to under-
water tanks,
3. Defective switch on air compressor,
4. Excessive vibration in Gorman-Rupp sewage pump, and
5. Missing operator key for valves.
The construction overflow pipe was sealed at its junction
with the outfall structure.
86
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CO
UNDERWATER STORAGE TANKS
Figure 37
-------
On November 5, 1968 the F.W.P.C.A. accepted the work com-
pleted under the construction phase of the project. Figure
38 shows the dike area being filled with bay water for
preliminary testing.
The dike remained in position to allow dewatering of the
tank area until December 24, 1968. This allowed possible
repairs to be made on the underwater portion of the stor-
age system. None were required. On December 24, 26, and
27, 1968, the dike was removed to allow operation of the
system in actual environmental conditions. The dike was
removed to a depth below the original bay elevations to
provide a place for the silt which had accumulated on the
outside perimeter of the dike to deposit prior to the ex-
cavated tank area. This was partially successful.
88
-------
00
UNDERWATER STORAGE TANKS
Figure 38
-------
SECTION VII
OPERATION PERIOD
The one-year operation period for the underwater storage
system was conducted from November 5, 1968 to November 5,
1969. During this period, the basic operation of the under-
water storage tank was shown to be successful. However,
mechanical difficulties occurred due to the numerous new
systems involved and new adaptions of equipment. Mechan-
ical failure also occurred in some of the standard monitor-
ing equipment. Record high lake levels and its associated
problems along with mechanical difficulties of monitoring
equipment prevented acquisition of all data required for
system evaluation.
The following pages contain a discussion of the testing and
storm events which occurred during the one-year period.
Detailed explanation of operation difficulties are given
as necessary.
Table 8 lists the periods for which the storage tanks were
in operation. The dates of the event, the volume stored,
the lake level, and pertinent operational comments are in-
cluded. The variance in times between filling of the tanks
and emptying of the tanks is due to the operator's schedule
and in certain cases to planned activities concerning one
or both tanks. With the sewage pump used, 100,000 gallons
of liquid could be pumped from the tanks to the interceptor
in about 60 minutes. However, using the high pressure pump
to fill the tanks during tests required from eight to
twelve hours each, depending on bay level.
During the year of operation, a total of 4,825,000 gallons
of liquid was stored in the two underwater storage tanks
of the pilot facility- Table 10 shows a breakdown of the
volumes for storm overflow and testing and the number of
times each tank was in operation. A total of 988,000 gal-
lons of storm overflow was intercepted and returned for
treatment by the pilot facility.
With continuous use of the monitoring equipment and operator's
observations of instrumentation, operation problems which
had not shown up in the initial testing were encountered.
Certain of these involved difficulties which persisted through-
out the year;others only required slight system modifica-
tion or adjustment for elimination.
91
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TABLE 8
TANK STORAGE DATA
*(F) Date Filled
(E) Date Emptied
*Date
1968
Oct.
25 (F)
26 (E)
25 (F)
26 (E)
- BEG!
Nov.
6 (F)
14 (E)
6 (F)
6 (E)
Dec.
26 (F)
26 (E)
Filling
Test
X
X
NNING OF
X
X
Storm
OPERATION
Volume Stored (Gal)
East
102,960
PERIOD NOVEI
99,900
101,750
West
116,000
1BER 5, 1968
98,000
- Lake
Level -
Monthly Max.
570.0
570.0
570.0
-
570.0
571.4
569.4
Comments
Preliminary Testi
Preliminary Testi
-------
TABLE 8
TANK STORAGE DATA
Date
Dec.
28 (F)
29 (E)
28 (F)
29 (E)
1969
Jan.
22 (F)
23 (E)
22 (F)
23 (E)
Feb.
15 (F)
16 (E)
Filling
"Test Storm
X
X
X
X
X
Volume Stored (Gal)
East west
104,340
190,875
140,000
91,200
82,125
- Lake
Level -
570.0
570.0
Monthly Max.
570.4
569.1
569.1
Monthly Max .
571.9
571.5
Comments
Storm Intensity 0.5
In./Hr. Max. 0.116
In./Hr. Average
Storm Intensity 0.5
In./Hr. Max. 0.116
In/Hr. Average
East Pressure Relief
Valve Open
Staff Gauge
Removed By Ice
I.D
U)
-------
TABLE 8
TANK STORAGE DATA
Date
15 (F)
17 (E)
17 (E)
26 (F)
26 (E)
27 (F)
March
13 (F)
13 (E)
31 (F)
31 (E)
April
9 (F)
10 (E)
Filling
Test Storm
X
X
X
X
X
Volume Stored (Gal)
East West
30,600
20,000
90,000
72,000
100,375
99,000
108,000
- Lake
Level -
571.5
571.2
571.2
571.2
Monthly Max.
572.0
570.7
571.3
Monthly Max.
573.5
573.5
Comments
Leaked In During
Night-Pressure
Relief Valve Open
To Check Leak
East Tank Not In
Operation
East Tank Not In
Operation
1# Dye -Testing for
Leak
ID
*>.
-------
TABLE 8
TANK STORAGE DATA
Date
14 (F)
16 (F)
23 (E)
18 (F)
21 (E)
May
10 (F)
11 (E)
10 (F)
11 (E)
June
Filling
Test
X
Storm
X
X
X
Volume Stored (Gal)
East
171,000
183,000
West
117,000
88,600
1
-Lake
Level -
571.4
572.3
Monthly Max
573.0
572.5
572.5
Monthly Max
572.4
Comments
5# Dye Testing
for Leak
Storm Intensity .17
In./Hr. Max. .079
In./Hr. Average
Storm Intensity .15
In./Hr. Max. .074
In./Hr. Average
Storm Intensity ,15
In./Hr. Max. .074
In./Hr. Average
-------
TABLE 8
TANK STORAGE DATA
Date
11 (F)
14 (E)
11 (F)
14 (E)
15 (F)
23 (F)
26 (E)
24 (F)
26 (E)
July
4 (F)
12 (E)
Filling
Test Storm
X
X
X
X
X
Volume Stored (Gal)
East West
Not
Available
Not
Available
109,000
Not
Available
Not
Available
- Lake
Level -
571.9
571.9
572.1
572.1
Monthly Max.
573.0
572.2
Comments
Filled For Cleaning
Water Removal Not
Checked By Operator
Filled For Cleaning
Water Removal Not
Checked By Operator
Filled For Cleaning
Water Removal Not
Checked By Operator
Elev. of Tank Top
571.1
VD
-------
TABLE 8
TANK STORAGE DATA
Date
4 (F)
10 (E)
17 (F)
20 (E)
17 (F)
17 (E)
Aug .
6 (F)
8 (E)
5 (F)
8 (E)
Filling
Test
X
X
Storm
X
X
X
Volume Stored (Gal)
East
Not
Available
241,500
West
Not
Available
Not
Available
180,000
Lake-
Level-
572.4
572.2
572.2
Monthly Max
572.7
572.1
572.1
Comments
Air Leak Caused Lake
Level to Empty Tanks .
Recorder to West Tank
Not Functioning. 5.8
Inches of Rain during
Storm.
Elev. of Tank Top
569.9
Elev. of Tank Top
570.4 Air Leaks
Allowed Lake Level
To Empty Tanks.
Elev. of Tank Top
569.9
West Tank Recorder
Not Functioning
-------
TABLE 8
TANK STORAGE DATA
Date
28 (F)
29 (E)
28 (F)
29 (E)
Sept.
6 (F)
7 (E)
7 (F)
8 (E)
8 (F)
9 (E)
16 &
17
Filling
Test Storm
X
X
X
X
X
X
Volume Stored (Gal)
East West
131,100
164,900
Not
Available
83,950
93,600
174,200
Not
Available
- Lake
Level -
572.1
572.1
Monthly Max .
572.8
571.8
571.8
571.9
Max. 572.8
Comments
Replacement of Ball
Float. Elev. of Tank
Top 569.1
Replacement of Ball
Float. Elev. of Tank
Top 564.8
35,000 Gal. Into Tank
Tanks emptied when
Water Level Reached
572.8
VD
00
-------
TABLE 8
TANK STORAGE DATA
Date
22 (F)
23 (E)
23 (F)
24 (E)
Oct.
9
&10 (F)
10 (E)
8&9 (F)
10 (E)
29
&30 (F)
31 (E)
29
&30 (F)
31 (E)
TOTAL
Filling
~ Test
X
X
X
X
Storm
Volume Stored (Gal)
East
155,600
126,000
116,000
West
106,400
149,000
101.000
- Lake
Level -
571.5
571.7
Monthly Max.
571.4
570.7
570.7
571.4
571.4
2,684,000 2,141,000
Comments
vo
NOTES: (1) Design elevation for tank operation 571.9
(2) Overflow invert 572.3 in connection chamber.
-------
TABLE 9
SUMMARY OF TANK STORAGE DATA
East Tank West Tank
(Rubber Bottom) (Steel Bottom)
Storm
Events 5 6
Gallons 496,000 492,000
Tests 14 16
Gallons 2,188,000 1,649,000
Total Gallons
Stored 2,684,000 2,141,000
Underwater Storage Tanks
The two underwater storage tanks installed in the pilot
facility in Sandusky, Ohio functioned as designed. A
few minor problems were encountered with the supporting
tank equipment but no operational difficulties were
actually encountered with the basic tank itself.
The west tank bottom was manufactured with 1/4" steel
sheet. This appears to be the better bottom design due
to economics and ease in determination of volume, tank
shape, and tank top action. However, the east tank with
its rubber bottom functioned properly and might be more
applicable for wet installation of the underwater storage
system. Dry installation would favor the steel bottom
tank design.
The flushing system was included to aid in controlling
sedimentation in the underwater tanks. Use of this system
in future storage tanks would depend on the physical and
chemical properties of the liquid to be stored. In gen-
eral, the flushing system might be deleted from future
underwater storage tanks.
During the operation period, the need for check valves
in the influent lines to the tanks was indicated. During
a storm event on September 16 and 17, 1969, the tanks were
filled with about 35,000 gallons of storm overflow. With
a high lake level of 572.82, the storm overflow was forced
out of the tank through the influent pipe and back through
the leaping weir to the interceptor.
100
-------
This occurred due to the differential head available, the
low leaping weir regulator elevations which exist, the ex-
treme water level fluctuations, and the influent control
valves not being designed to close with a partially filled
tank.
During a test filling of the east tank on January 1, 1969,
a total of 190,000 gallons of water were pumped from the
tank. Since the operator had estimated that about 120,000
gallons had been pumped into the tank, it seemed that a pro-
blem had developed. The east tank could hold such a quantity
at about seven percent fabric elongation. The high pressure
pump capacity was erratic in pumping due to its application.
However, it was decided that the pressure relief valve should
be checked to see if it was open. The west tank functioned
properly during this testing.
On February 15 and 16, 1969, the east tank was again filled
with bay water and 140,000 gallons were pumped out. On Feb-
ruary 16, 1969, the operator noted that water was coming
out of the influent pipe to the east tank in the connection
chamber. On February 17, 1969, the operator pumped 30,000
gallons from the east tank. The east tank was not empty
and the lake level was forcing bay water out of the tank.
Early explanations were that either a leak had occurred in
the east tank and its associated piping or the pressure re-
lief valve was open. On February 27th, two divers found the
relief valve open. The springs were caught on the rods used
to guide the top plate. The pressure relief valve was
closed and the sewage pump was started to empty the tank.
After the tank was empty (tank height being monitored by the
T.L.C.S.), the pump still produced water with large amounts
of silt and clay. (This problem was not explained until
June, 1969. The gas vent valve float ball had partially fail-
ed during the period and did not seal under partially filled
tank conditions.) Divers then checked the tanks but found
no leaks. A fine layer of silt covered the tank and the vis-
ibility was very poor. Further investigations were necessary.
A decision was made to fill the east tank to capacity and
then add dye. This was done on April 9, 1969 after the ice
had left the bay, and 90,000 gallons of bay water were
pumped into the tank and one pound of die was added. On
April 10, 1969, divers inspected both underwater storage
tanks. Due to the silt covering the tank and the wave action,
visibility was negligible. No leaks were found. No dye
was found in the water.
101
-------
On April 15, 1969, 120,000 gallons of bay water was pumped
into the east tank and then five pounds of yellow dye was
added with another 50,000 gallons of bay water. On April
18, 1969 a severe storm event occurred. The west tank was
filled with the 170,000 gallons of water and five pounds of
dye. No leakage of the dye was found. The east tank was
pumped out on April 23, 1969 after divers again checked the
tank.
The pressure relief valve might have opened and closed it-
self for the leakage on February 27, 1969. On April 23 and
24, 1969, the pressure relief valves were removed. Teflon
tubing was inserted over the rods to provide a smooth sur-
face. The holes drilled in the bottom flange were oversized
and the tubing reduced the excess clearance from these holes.
One of the causes for the opening of the pressure relief
valve was the layer of fine silt which had accumulated over
the two tank tops. This layer consisted mainly of a grey
silt and clay with some pebbles and rocks from the April
storm and was from two to six inches deep. A new breakwall
near the pilot facility was washed out by this storm add-
ing to the material deposited.
The accumulation of silt created operational problems with
the pressure relief valves in filling the tanks and with
the T.L.C.S. The silt on the tanks caused additional head
of 0.125 to 0.167 feet to be necessary to fill the tanks.
With the low head conditions existing at the pilot facility,
this created a problem in operation due to the high bay
levels and the maximum static head allowed in the connection
chamber prior to backing up flow in the McEwen Street sewer.
It was decided that the silt would have to be removed. At-
tempts to get commercial pool cleaning firms to do the work
were unsuccessful since their work schedules were filled.
It was also suggested at this time that an explanation of
the infiltration of water to the connection chamber might
be caused due to malfuctioning of the gas vent valves. It
was decided to examine the gas vent valve at the time of silt
removal.
On June 24 and 25, the silt was vacuumed off of the two
underwater storage tanks. The two tanks were filled to
about 200% of their rated 100,000 gallon capacity. The
removal was accomplished using a centrifugal pump and an
industrial vacuum head capable of pumping one inch solids.
Personnel were able to stand on the filled tanks. The
cost of silt removal was about $400.00 per tank.
102
-------
A diver checked the four corner gas vent valves on each
tank. NO problems were found with any of these valves.
However, on inspection of the center gas vent valves, both
copper float balls were found to have failed preventing
sealing against the top seal seats except under high inter-
val tank pressures. Also corrosion of the aluminum guides
for the float balls allowed the balls to hang up for short
periods.
The center copper float balls were replaced, then on August
8, 1969, these were replaced with float balls made of 20 gage
stainless steel. No further infiltration was noted through
the end of the operation period.
The corner gas vent valves do not experience the severe
piston type action of the center gas vent valve and stronger
float balls were not necessary. The corner gas vent valves
need not be installed in future underwater storage tanks
with this shape. A single center gas vent valve can do the
required job.
Tank, Level Control System (T.L.C.S.)
In order to provide a system to monitor tank volume, the T.L.
C.S. has to function consistently in the bay environment.
Several problems were encountered in the operation of the
system due to errors in operating procedure and the bay en-
vironment with its associated waves and silt.
Prior to the installation of the underwater storage system,
the bubbler type depth measurement system had not been used
except in standard industrial and municipal projects. In
these applications, the liquids monitored were usually flow-
ing in one direction while fluctuations in liquid level were
steady without waves. While solid particles were encountered
in these installations, a deposit of these particles over
the bubbler was easily prevented by bubbler location or
periodically flushing them away.
The air supply for the T.L.C.S. was sized for the system
using the quantity it would require in a typical application
for a basis of design. The volume of air was increased by
50% over this. However, after initial operation of the
system, it was soon established that the air requirements
were much in excess of those provided. A second compressor
of 3/4 h.p. capacity was installed in series with the first
1/3 h.p. unit to provide an adequate air supply.
103
-------
The situation of air supply was compounded when air was
required to be released through the bubbler lines on the
top of each tank and at the reference elevation at a
faster rate than was intended during the operation period.
This increase in air feed was required due to the accumula-
tion of fine silt over the bubbler lines. Better T.L.C.S.
system accuracy was accomplished with the use of the higher
air feed rate.
After the first month of operation, fluctuations were noted
which were not entirely representative of actual events as
the internal bellows were subjected to a pressure higher
than operating pressure. The bellows were strained to a
point outside of their range of calibration. With the zero
to 23 foot range of operation this distortion and the time
required for the bellows to return to calibration required
two changes.
The first change was the elimination of higher pressures.
During normal operation of the T.L.C.S., the operator at
the pilot facility forced any water out of the bubbler lines
and cleared silt away from the bubbler lines by forcing 20
psi air through these lines. However, the bellows were also
subjected to this 20 psi pressure while operating at 3 to
15 psi. It was found that by eliminating this 20 psi pres-
sure, the drift or fluctuation of the recorded data due to
straining of the bellows was eliminated. The T.L.C.S. as
installed allowed isolation of all transmitters while blow-
ing out the bubbler lines with the 20 psi air.
The second change made was to use 100% of the 0 to 23 feet
bellows range. Operation had been tried using the 0 to 23
feet range at 50% to 30% proportional band and 0 to 80 inch
range at 100% proportional band to provide more accuracy.
However, the tracking of the bellows was found to be non-
linear during calibration procedure. No bellows are avail-
able between the 0 to 23 foot range and the 0 to 80 inch
range. The bellows for the pilot facility should have an
optimum range of 0 to 120 inches. The 0 to 23 foot range
does not allow as accurate a control as a 0 to 120 inch
range would.
This second change allowed the best control of the liquid to
be stored in the tank. Under the most severe storm events,
the liquid caught by the tanks was 50,000 to 80,000 gallons
higher than that during other storm events. This was due to
the fluctuation of the tank top during storm events. Since
the tank top height was used to determine the tank volume
and the point at which the influent control valve closes,
tank top elevation fluctuation created by wave action along
104
-------
with the slight insensitivity and time delay in the pneu-
matic system allows a larger fluctuation in tank capacity.
The fluctuation in tank capacity was not critical in the
original tank design of 100,000 gallons since design was
based on zero fabric elongation. However, designs incor-
porating a 6% fabric elongation for future installations
will require the more positive control of the volume of
liquid storage provided.
Another problem encountered in the operation period consist-
ed of the deposits of silt which accumulated over the bubbler
tubes. These silt deposits caused an inaccurate reading due
to the increased weight of material causing higher erroneour
pressure readings. The major portion of this problem was ex-
perienced at the reference bubbler attached at the tank frame.
Silt accumulation of 1/2 to 1 inch did not cause difficulties;
however, larger accumulations did. Increases in the rate of
feed helped reduce this difficulty and periodic removal of
silt around the bubbler was required.
The last problem encountered with the T.L.C.S. during the
operation period was a leaking air valve prior to the three-
way switching valve which controls the 12-inch Vee-Ball
influent control valve. The 12-inch Vee-Ball valve is a
positive control valve in that when air supply is lost the
valve closes. The three-way switching valve operates such,
that when the tank is filled, on a signal from the trans-
mitters the air supply to the valve is shut off and the line
to the valve is opened to atmosphere, closing the valve.
Since the valve is open at 20 psi and closed at about 3 psi,
if a pressure greater than 2 psi is applied to the line by a
leaking air valve, the valve opens slightly-
Two times in July, 1969 storage data was lost when air leaks
occurred after the tanks were filled and the valves opened
partially. With bay levels being higher than other eleva-
tions in the storage system and the McEwen Street regulator,
the stored overflow was forced out of the tanks through the
influent piping and back through the leaping weir to the
interceptor. The stored liquid did not got into the bay. This
system was corrected by attaching an additional regulator
after the three-way switching valve. After the valve is closed
and air pressure drops past 15 psi, the regulator opens the
line to the control valve to atmosphere. Before the control
valve can be opened again, the additional regulator must be
closed manually.
Flow Measurement
The system used to monitor dry-weather flow from the drainage
105
-------
area and to record storm overflow to the connection cham-
ber incorporated Leupold & Stevens Model S61R ball float
type transmitters with remote recorders. The dry-weather
transmitter was calibrated to measure flow through an exist-
ing 12-inch wide concrete channel in the existing regulator-
over-flow device. The storm overflow transmitter was used
in conjunction with a special 30 inch Leupold-Lagco flume.
The transmitters were both mounted in existing regulator
chambers. These components were subjected to the atmospheric
conditions encountered in combined sewers. The problems
encountered during the period of operation consisted mainly
of incomplete sealing of the transmitter housing. When this
occurred, internal mechanical and electrical parts corroded.
Corrections of this problem required replacement and cleaning
of parts and complete sealing of both units.
The Leupold and Stevens recorders for the transmitters also
required attention. The signal from the transmitter to the
recorder was sensitive to electrical interference. When
first installed in the control building, the flowmeter wiring
was not shielded properly. This caused excessive chattering
and wearing of internal gears which needed to be replaced.
Shielded wire was installed and isolation transformers on the
incoming power helped reduce this problem.
The friction feed of the chart paper in the recorders caused
many difficulties in obtaining data on a correct time basis.
Table 10 shows periods of time in which the flow measurement
system was not operating during the operational period with
reasons for the inoperation.
The Leupold and Stevens units were in operation from March,
1968. They were originally housed in a temporary metal
building. The units were transferred to the control building
in October, 1968.
The Fischer-Porter magnetic flowmeter monitoring storm over-
flow pumped from the storage tanks operated consistently
throughout the operational period. No difficulties with
this unit nor its recorder were encountered.
Flooding of Interceptor
An unexpected difficulty encountered during the one-year of
operation, which was not anticipated from site investigations
prior to construction, was, surcharging of the interceptor
106
-------
TABLE 10
FLOWMETER OPERATION
Date
1968
Nov.
Dec.
1969
Jan.
Feb.
March
Dry-Weather Flow
Transmitter Recorder
Excessive
chattering
Excessive
chattering
and wearing
of gears
Recorder
chart mech-
anism broken
Jan. 2-24
(pen not oper-
ating contin-
ously)
Storm Overflow Flow
Transmitter Recorder
Excessive
chattering
Excessive
chattering
and wearing
of gears
Chattering
Comments
Company
Contacted
Shielded
wire installed
Potentiometer
replaced and
transmitter
sealed.
Isolation
Transformers
installed
Feb. 14.
-------
TABLE 10
FLOWMETER OPERATION
Date
1969
April
May
June
July
Aug.
Sept.
Dry Weather Flow
Transmitter Recorder
Potentiometer
corroded -
Erratic Opera-
tion
Repaired Poten-
tiometer June
20
Potentiometer
corroded out
Sept. 18 re-
placed Sept.
24.
Replaced
gears and
potentio -
meter June 9
Ink pen
broken Aug.
31.
Ink pen
replaced
Sept. 18
Storm Overflow Flow
Transmitter Recorder
Parts broken
on April 19
Out of opera-
tion
Repaired on
May 27
Comments
o
00
-------
TABLE 10
FLOWMETER OPERATION
Date
1969
Oct.
Nov.
Dry-Weather Flow
Transmitter
Oct. 21 to 27
Potentiometer
corroded and
gears corroded
Removed Oct. 27
Recorder
Electricity
Storm Overflow Flow
Transmitter Recorder
to both units sh
Removed Nov. 5
due to corroded
shafts
it off at pane
Comments
1
-------
sewer. Part of this problem was due to the extremely high
water levels encountered from April, 1969 to September, 1969
and the poor tide gates and low regulator - overflow elevations
existing in the combined sewer collection system.
At the McEwen Street regulator-overflow device, the inter-
ceptor to the water pollution control station was flooded
at times by bay water flowing back through the Ogontz Street
outfall and through the Ogontz Street regulator into the
interceptor. When the City of Sandusky completed installa-
tion of nine new tide gates, including one at the Ogontz
Street outfall in July, 1969, flooding of the interceptor
with bay water was reduced.
Upstream from the McEwen Street connection to the intercep-
tor, two contributing drainage areas feed the interceptor.
The first drainage area immediately east is the Arthur Street
drainage area which consists of about 323 acres drained by
combined sewers. The regulator device at the Arthur Street
connection to the interceptor is a No. 3 Brown and Brown au-
tomatic sewage regulator which has a rated capacity of 3.75
CFS at 0.1 feet of head and 11.90 CFS at 1.0 feet of head
with an open gate. Actual hydraulic capacity and operation
of this regulator was not determined. It is expected that
the regulator closes with a head of three to four feet.
The second drainage area is controlled by the Farwell Street
pump station which pumps sanitary sewage from the sanitary
sewer collection system east of the Arthur Street drainage
area and Cedar Point. Pump capacity at the Farwell Street
pump station is 13.5 MGD (20.88 CFS). This maximum flow
rate occurs periodically during five minute intervals when
pumping the wet well down. Three pumps are used to supply
this flow rate. Lesser flow rates occur over longer inter-
vals supplied by one or two pumps.
The interceptor capacity above the McEwen Street connection
is about 25.0 cfs maximum and about 23.5 cfs when flowing
full. Beyond the McEwen Street connection, the interceptor
capacity xs about 28.0 cfs maximum and 27.0 cfs when flowing
full.
During storm events, the Arthur Street drainage area contri-
butes 0 cfs to a peak of over 11.9 cfs and the Farwell Street
pump station contributes peaks of 20.88 cfs. This total
flow is in excess of the interceptor capacity. When the inter-
ceptor was flooded with bay water by high water levels during
storm periods, surcharging of the interceptor by the Farwell
Street pump station caused water to be forced up through the
McEwen Street regulator device. This created problems in
110
-------
gathering representative samples of combined sewer storm
overflow and in measurement of both dry-weather flows and
storm overflows.
Investigation of blueprints of existing sewage collection
systems and discussion of the operation of the system in the
area of the pilot facility with the sewer maintenance crews
did not indicate the possible surcharging at the interceptor
by the Farwell Street pump station.
Electrical Power Costs
One of the major operational costs during the one-year oper-
ation period for the pilot facility was electrical power
costs. The relative high cost for power is due to the high
load demand put on the power supply for short periods of time.
The pilot facility required power supply for the following
items:
1. Thirty HP electric motor on sewage pump;
2. Fifteen HP electric motor on high pressure pump;
3. Three, 1 HP electric motors on miscellaneous pumps;
4. Electric lighting, water heater, and baseboard heaters;
5. Flow meters and recorders; and
6. Miscellaneous solenoid valves and laboratory equipment.
The power requirements for the facility were 120/208 volt
three phase service for which lines had to be extended from
existing Ohio Edison Company lines. Since the pilot facility
was considered a commercial establishment, it had to be on a
demand meter. The net monthly billing load in KW was based
on 60% of the highest billing load during the preceding
eleven months or the measured load for the month whichever
was greater, as determined by highest 30 minutes load record-
ed by the demand meter.
After the first three months of operation, the procedure
used in operating the pilot facility during emptying of the
underwater storage tanks was to supply all electric power
with the auxiliary power system except for the 30 and 15 HP
pump motors during tank emptying to reduce this peak demand.
Both pumps were not operated at the same time. But were
alternated as desired. This peak demand was experienced
only on an average of four hours per month. Since the billing
was based on 60% of the highest billing load for the preced-
ing eleven months, no larger reduction in power cost was
experienced during the one-year of operation.
Ill
-------
Future installations should be designed to exert a minimum
power demand on the power supply. Trickling pumps might be
used where emptying of storage tanks over a short time is
not necessary. Determination of the maximum and minimum
time available to pump stored liquid from the storage tanks
must be accomplished before operation costs for underwater
storage systems can be determined.
Operation Manual
An operation manual for the pilot facility in Sandusky, Ohio
was required during the beginning of the operation period.
The operation manual was submitted with corrections on Feb-
ruary 14, 1969 and accepted by the F.W.P.C.A.
Operational procedures were explained in detail. Major items
included were:
1. Analysis of storm water runoff;
2. Storage Operation;
a. Filling during storm event
b. Filling without storm event
c. Emptying storage tanks,
d. Piping valve location and operation, and
e. Pump operation and maintenance;
3. T.L.C.S.;
4. Flow measurement,
5. Auxiliary power and electricl system; and,
6. Rain gage operation.
Manufacturer's operation and maintenance manuals were used
in conjunction with this operation manual.
Safety
During November, 1968, a security fence was installed around
the pilot facility control building and connection chamber.
The fence was added to prevent injury to children who play
in the area and to reduce possibility of vandalism.
On January 2, 1969, a letter was sent to the offices of Rohrer
by the City of Sandusky requesting the installation of a fence
along the bay shore westward from the existing fence and para-
llel to the railroad tracks and also northward from the exist-
ing fence along the bay shore. The fence was to extend to
the limits of the deeper water covering the underwater stor-
age tanks. Parents in the area of the pilot facility had
voiced an opinion of the possibility of children playing in
112
-------
the deeper water over the tank area. Prior to the pilot
facility installation, water depth was only two to four feet
deep in this area.
A difficulty in installation of this fence existed due to
the rights of free access to the bay of landowners adjacent
to the bay. If this additional fencing had been installed,
free access would have been impaired. Legal action against
Rohrer and the F W.P.C.A. could be brought. Additional
fencing might have prevented help from reaching any child
in distress.
The area surrounding the pilot facility is used each winter
to park ice-boats. Additional fencing would have prevented
present use and might have contributed to public rejection
of the system.
A letter of explanation was sent to the City Manager on Jan-
uary 6, 1969 requesting that the City should bear responsibi-
lity for any litigation by adjacent landowners arising from
installation of the fence. The matter was dropped.
It does not seem feasible at this time or any future time
that all shoreline can be fenced at future installations.
Installation of system pumps and controls in prefabricated
underground pump stations would tend to reduce the need for
any fencing and would probably be more acceptable by adjacent
landowners.
Underwater storage tanks for this system can in many in-
stances be placed in deeper water or further from the shore.
However, system costs and installation costs may be lower
with near-shore tank location where possible.
Three signs warning of deep water had originally been instal-
led around the tank area during December, 1968.
113
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SECTION VIII
EVALUATION
To evaluate the feasibility of the underwater storage system,
the reduction in pollution load from the combined sewer must
be determined and the cost of the system must be determined.
To evaluate the best approach for pollution abatement, a
comparison of the reduction of pollution provided and a com-
parison of costs on a similar basis must be accomplished for
each combined sewer drainage area.
To determine the most economical approach to combined sewer
pollution abatement, the entire range of methods, sewer sep-
aration, storage, treatment, and storage with treatment, must
be examined. The degree of treatment provided by each along
with the degree of pollution abatement necessary must be
known. In most cases, use of several methods of pollution
control will produce the most economical pollution abatement
method for a combined sewer system.
Elimination of 100% of all combined sewer storm overflow is
usually impractical unless unlimited funds are available.
This is due to the large volume of runoff produced by nat-
ural events. During the year of operation of the pilot
facilitv in Sandusky, Ohio a storm event on July 4th and
5th yielded 5.57 inches of rainfall over an eight hour per-
iod. The average intensity was 0.70 in/hr with intensities
experienced over 3 in/hr. Estimated runoff for the McEwen
Street drainage area of 14.86 acres was a minimum of 1.46
million gallons. Estimated runoff from the Sandusky com-
bined sewer area of 2205 acres was a minimum of 216 million
gallons. This storm is estimated as a 75 to 100 year storm
event.
During the year of operation, storm events of 1.84 inches on
December 28 and 29, 1968 and 1.61 inches on July 17, 1969
have according to present recurrence curves a return period
in excess of the preliminary design storm. Runoff from the
two events was estimated at 330,000 gallons and 250,000 gal-
lons respectively. Tank capacity during the first storm was
set at 100,000 gallons each. Tank capacity during the se-
cond storm was in the process of being increased from 100,000
gallons to approximately 150,000 gallons.
Storm Interception
The design storm used to size the capacity of the pilot fac-
ility was a one-year storm of sixty minute duration. The
115
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related intensity seemed to be 1.30 in/hr from preliminary
analysis of excessive short duraiton rainfall. Using the
1.30 in/hr intensity and a weighted runoff coefficient of
0.42 to determine expected storage capacity of the under-
water storage tanks, a capacity of 218,000 gallons would be
needed. A basic tank capacity of 100,000 gallons was used
for design of each tank. This was provided at zero fabric
elongation.
In 1969, intensity - duration - frequency curves were con-
structed from excessive short duration rainfall for 1942 to
1964 from Sandusky WB station data. These curves indicate
an intensity of 1.0 in/hr corresponding to the one-year
storm of sixty minute duration. Assuming a weighted coe-
fficient of 0.42, the resulting storm runoff volume would
be about 168,000 gallons.
Using the 200,000 gallon basic tank capacity, and the inten-
sity - duration - frequency curves, the pilot facility would
intercept a two-year storm of 60 minutes duration with a
corresponding intensity of 1.20 in/hr. The runoff volume
was determined using the 0.42 weighted runoff coefficient.
Since zero fabric elongation was used as a basis of the 100,
000 gallon tank capacity design, additional storage capacity
exists in the pilot facility tanks. When the underwater stor-
age tanks were designed, no data was available on the use of
neoprene rubber coated nylon fabric for underwater storage of
combined sewer overflows; and, the manufacturer would not
recommend working design fabric elongation for the proposed
environment.
After the completion of the operation period and the obser-
vation of the fabric in operation in the underwater environ-
ment, it is recommended that a six percent elongation be
used as a maximum elongation for the tank design and fabric
to be used. The use of six percent fabric elongation creates
additional storage capacity of about 80,000 gallons in the
west tank and slightly more in the east tank. Therefore,
existing tank capacity, which can be used at the existing
facility, is about 360,000 gallons.
Using the intensity - duration - frequency curves, the
360,000 gallon capacity will intercept a ten-year storm of
100 minute duration with an associated 1.25 in/hr intensity.
This runoff volume was calculated using the 0.42 weighted
runoff coefficient. All storms with a more frequent re-
turn interval will be intercepted unless flow rates to each
116
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storage tank is exceeded. This will occur at intensities
in excess of 2.00 inches per hour with durations equal to
or greater than the time of concentration for the drainage
area.
One part of the work which was to be accomplished during the
year of operation was the determination of the runoff coeffi-
cient for the drainage area versus preceding rainfall, inten-
sity of rainfall, and duration of rainfall. Since the flow-
meter installation did not operate properly sufficient data
was not obtained for this determination. However, for mod-
erate intensity and duration storms such as a one-year storm,
a runoff coefficient of 0.32 to 0.35 would more closely fit
the drainage than the 0.42 design coefficient.
Costs
The construction costs for the pilot facility are given in
Table 11. Major costs which might be avoided in the future
are $57,000 which was required for rock excavation and
$30,489 which was the additional cost of the east tank over
the west tank. It should be possible to avoid extensive
rock excavation at future sites in Sandusky, Ohio by reduc-
ing the depth of water over the storage tanks at a filled
condition. The additional material cost and fabric instal-
lation costs of the bottom fabric of the east tank reduces
the east tank's desirability from an economic aspect. Other
cost reductions can be achieved in future non-research in-
stallations by reducing instrumentation and recording equip-
ment and using an underground prebuilt pump station to house
all pumps and controls.
TABLE 11
Pilot Facility Construction Costs
Site Preparation (Dry Installation) $128,217
West Tank (Steel Bottom) 63,631
East Tank (Rubber Bottom) 94,120
Connection Chamber and piping 19,200
Control Building and pumps 38,230
Instrumentation 29,175
Miscellaneous Construction 4,055
TOTAL $376,628
Table 12 shows a comparison of the cost of the pilot facility
at original design capacity to existing storage capacity at
117
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allowable six percent fabric elongation. These costs are
extremely high per gallon due to the added costs arising
from rock excavation, instrumentation, and control building.
TABLE 12
Construction Cost Per Gallon of Storage Capacity
Pilot Facility Sandusky, Ohio
$/Gallon
Design Capacity
200,000 Gallons 1.88
6% Elongation Capacity
360,000 Gallons 1.04
Future underwater storage installations without the data
gathering capabilities of the existing pilot facility can be
built at a lower cost per gallon of storage capacity. Esti-
mates by Rohrer of underwater storage cost based on present
tank design are shown on Table 13. A cost of 42.5 cents per
gallon could be achieved at a 200,000 gallon storage capa-
city and a cost of 35.9 cents per gallon could be achieved
at a 1,000,000 gallon storage capacity. Future installa-
tions would consist of:
1. Basic storage tank, with pressure relief valve, sedimen-
tation chamber, and gas vent valve;
2. Modified connection chamber with bar screen and safety
overflow;
3. Underground prefabricated pump house for pumps and con-
trols; and
4- Tank volume control system.
Additional cost reductions could be achieved at favorable
locations with sufficient available hydraulic head, sufficient
water depth and minimum wave forces, and modified tank design
for wet installations. The tank volume control system would
operate from fabric elongation. Figure 39 shows a flow dia-
gram for simplified future installations.
Use of 8% to 12% working fabric elongation with maximum elong-
ation of 18% is possible after more operational data is se-
cured. This would increase existing tank capacity from the
180,000 gallons at 6% elongation to 210,000 gallons at 8% el-
ongation or 223,000 gallons at 12% elongation.
Table 14 shows projected construction costs for a 200,000
gallon storage capacity incorporating these design changes.
118
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COMBINED SEWER FLOW
DRY WEATHER FLOW
CONNECTION
CHAMBER
SAFETY
OVERFLOW
BAR SCREEN
TANK VOLUME
CONTROL
SYSTEM
UNDERWATER
STORAGE
TANKS
TYPICAL INSTALLATION
TEMPORARY UNDERWATER STORAGE OF COMBINED SEWER
STORM OVERFLOW
KARL R. ROHRER ASSOCIATES, INC.
AKRON, OHIO
FIGURE 39
119
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TABLE 13
Construction Cost for 200,000 Gallon Storage Capacity Based
on 6% Working Fabric Elongation
Site Preparation (Wet Installation) $13,700
Tank (Steel Bottom) 54,630
Connection Chamber and Piping 8,600
Pump Station 6,500
Instrumentation 1,500
$84,930
Cost for 1,000,000 Gallon Storage Capacity Based on 6%
Working Fabric Elongation
Site Preparation (Wet Installation) $ 43,500
Tanks (Steel Bottom base 200,000
gallon capacity) 273,150
Connection Chamber and Piping 27,020
Pump Station 7,500
Instrumentation 7,500
$358,670
TABLE 14
Construction Cost for 200,000 Gallon Storage Capacity Based
on 8% Fabric Elongation, Modular Tank Design, and Minimum
Wave Force
Site Preparation (Wet Installation) $13,700
Tank 29,570
Connection Chamber and Piping 8,630
Pump Station 5,800
Instrumentation 1,200
$58,900
120
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The cost would be about 29.4 cents per gallon of storage
capacity.
Land costs are not included in the cost figures given. In
cases where property or right-of-way has been obtained for
sewer lines or property is already owned for other reasons,
additional system costs for land to install the pump station
on will be negligible. Where any appreciable amount of land
has to be purchased, cost per gallon of storage will reflect
this cost.
Operation costs for the pilot facility in Sandusky, Ohio
were far in excess of future systems. Future systems should
be relatively maintenance free and require checking by main-
tenance personnel only after major storm events and at regu-
lar intervals.
Estimated minimum operation costs for the Sandusky, Ohio
pilot facility are about $4,500 per year. Variation in this
minimum cost will vary greatly with the cost of electricity
or other power supply for the pumps used. The pump capacity
and the minimum allowable time available to pump out the
storage tanks will need to be determined prior to accurate
estimates of operation costs for future installations.
Monthly testing of the underwater tanks is unnecessary and
uneconomical. However, testing of the tanks by filling with
bay water should be done annually.
Table 15 shows a comparison of the cost of storage capacity
for the underwater storage tank compared to underground con-
crete tanks or lagoons. The projected cost does not include
preliminary studies for each site, extra costs encountered
due to specific site conditions, land acquisition, acquisi-
tion of all permits, and major alterations to existing
structures. Operation costs are not included.
With the cost comparison figures in Table 15, it can be
seen that underwater storage can readily compete with other
types of storage where applicable. Land costs which increase
the cost per gallon of storage will not be as great as for
other types of storage. Many times land will not be avail-
able. Aesthetics for the underwater and underground tank are
comparable. However, open lagoon storage is a poor method
to be used in populated areas. Public health regulations
may prohibit this type of storage.
121
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TABLE 15
Storage Capacity Construction Cost Comparison
(Based on Costs for Sandusky, Ohio Area)
Storage Capacity Construction Cost/Gal
Storage Method In Gal. Cost in $ in C/gal
1. Underwater 200,000 84,930 42.5
tank 1,000,000 358,670 35.9
2. Reinforced Con- 200,000 95,820 47.9*
crete Tank 1,000,000 351,740 35.2*
3. Lagoons 200,000 22,800 11.4*
1,000,000 102,000 10.2*
Note: Engineering studies and design, land cost, acquisition
of permits are not included in cost figures.
* Solids removal is not included in these cost figures.
For the Sandusky, Ohio combined sewer system, Rohrer completed
preliminary construction costs for several methods of combined
sewer pollution abatement. These estimated costs are shown
in Table 16 alona with cost estimates from other sources for
similar or other pollution abatement methods.
Comparison of the underwater storage with partial storage or
in-system storage systems or partial treatment systems is
meaningless unless the degree of pollution reduction is
known.
Storage alone is insufficient without a minimum of primary
treatment and chlorination. Secondary treatment of storm
flow would present difficulties where biological secondary
treatment is used, and phosphate removal might be necessary.
No costs can be determined for added treatment capacity until
minimum pumping periods of the stored overflows are determined,
Expansion of existing treatment facilities would depend on
what time would be allowed for emptying all storage tanks
and the DWF to the treatment facility compared to design flow.
If stored overflow could be pumped to the treatment facility
over longer periods (three days to a week), treatment facili-
ties could possibly handle the flows at non-peak hours (dur-
ing the night and over weekends) In this manner, increased
capacity might not be required.
122
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U>
TABLE 16
COMBINED SEWER POLLUTION ABATEMENT
Location
and
Method
I. Storage
Area
Served
In Acres
1. Sandusky, Ohio
Underwater Storage
(1 year storm)
580
2. Sandusky, Ohio
Underwater, under-
ground, and surface
( 1 year storm) 2205
3. Chicago, Illinois^
Chicago Deep
Tunnel
(100 year storm) 192,000
4. Saginaw, Mich.^
Lagoons
5. National-'-
COST COMPARISON
Cost
($ x 106)
3.57
7.75
1,270
Cost Per
Gal
(C/Gal.)
40.0
26.1
Cost Per
Acre
(4/Acre)
6160
3500
6615
415 to
5140
20 to
6500
Cost Per
Capita
($/Capita)
212
423
62 to
670
6 to
1300
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TABLE 16
COMBINED SEWER POLLUTION ABATEMENT
NJ
Location
and
Method
II. Treatment
(Primary with
Chlorination)
1. Sandusky, Ohio
Increase in plant
and interceptor
capacity
(1 year storm)
Area
Served
In Acres
2205
III. Sewer Separation
1. Sandusky, Ohio
No. plumbing changes
in individual
structures 2205
2. Sandusky, Ohio
Complete
3. Midwest^
Complete
2205
COST COMPARISON
Cost
($ x 106)
17.2
30.6
44.1
Cost Per
Gal
(
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TABLE 16
COMBINED SEWER POLLUTION ABATEMENT
COST COMPARISON
Location Area Cost Cost Per Cost Per Cost Per
and Served ($ x 106) Gal Acre Capita
Method In Acres (C/Gal.) ($/Gal.) ($/Capita)
4. Nationall
No Plumbing
changes 30,400 1020 835
M 5. National-'-
M Complete 48,800 16,320 1300
^U.S. Department of the Interior, Federal Water Pollution Control Administration,
"Problems of Combined Sewer Facilities and Overflows, 1967 "Water Pollution Control
Research Series, No. WP-20-11, by the APWA, December 1, 1967.
2Bauer, William; Dalton, Frank E., and Koelzer, Victor, The Chicagoland Deep
Tunnel Project, Metropolitan Sanitary District of Greater Chicago, September, 1968.
-------
Investigation of the pollution load from combined sewer
drainage areas must be conducted to determine allowable
times over which stored overflow can be pumped out. Deter-
mination of the length of time for significant buildup of
deposits of sanitary wastes in combined sewers should be
made.
Separation of sewers may not be the economical answer for
elimination of combined sewer pollution load. From studies
conducted during the past decade, evidence is that the total
pollution load from storm overflow from combined sewer systems
is not from sanitary flow only. About 80% of the pollution
load is due to the sanitary wastes. The other 20% of the
pollution load is entirely due to storm runoff. References
2, 3, 4, and 25 in the Bibliography of this report indicate
this pollution load. Further studies should be made to
further define the extent of the pollution load from storm
sewer systems.
Storage Capacity and Pollution Reduction
Temporary storage of storm overflow from combined sewer
systems is a method proposed to reduce water pollution. The
principal mechanisms of this pollution reduction are con-
tainment and delay. Combined sewage which would normally
overflow to the receiving waterbody is contained within the
storage facility where treatment is delayed until such time
that the normal sewage treatment plant has the capacity to
process it. It can be seen that the pollution reduction of
such a system is a combination of the percentage of the pol-
lution load contained and the degree of treatment afforded
at the sewage treatment plant.
Certainly other factors complicate the problem such as inter-
ceptor capacity, strength and freshness of the stored over-
flow, treatment plant capacity, and frequency of recurring
storm events. However, under the most optimum conditions,
the maximum pollution reduction which would be possible is
the product of the pollution load contained and the degree
of treatment at the sewage treatment plant. If 100% of all
overflow from any storm or combination of storms could be
contained, the problem would simply be the treatment afforded
by the sewage treatment plant. It can be seen that the
storage capacity is directly related to the pollution reduc-
tion capability of such a storage system.
As storage capacity is increased to intercept larger storms,
however, the cost of pollution containment increases dispro-
portionately. At some point it becomes more expedient for
126
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the cost of pollution reduction to apply the funds toward
improving the degree of treatment at the sewage treatment
plant.
Advocates of partial storage systems point out that the
major pollutant load encountered in storm overflow from
combined sewers occurs during the first flushing action of
a storm. If storage can be provided to accomodate this
first flush of water, a high degree of pollution control will
be accomplished at much less capital investment than with
sewer separation or total storage systems.
It is understood that partial storage systems will not pro-
vide 100% capture of storm overflow from combined sewers.
However, if the initial overflow from each storm may be
captured, the excess overflows will be much less deleterious
in water quality.
As an example, consider the storage of one inch of rainfall
in the Akron, Ohio area. For 83 years of record, 87 separ-
ate storms occurred producing more than one inch of rain-
fall. If the rainfall in excess of one inch were compared
to the total rainfall for this period, it amounts to only
4.2%^. If it can be assumed that 20% of the total combined
sewer load is due to storm runoff, than only 0.84% of the
total runoff pollution would overflow the one inch storage
facility. Consider also the duration of overflow events
corresponding to storm events in excess of one inch. Again
for the 83 years of record, overflows occurred 0.31% of the
time. If it can be assumed that 80% of the pollutional
load is attributed to sanitary sewage, then 0.25% of the
total sanitary sewage pollution would overflow the one-
inch storage facility. It is evident therefore, that only
about 1.1 percent of the total combined sewer pollution
load could escape a one-inch rainfall storage facility.
Even considering the severe storm experienced July 4th and
5th during the year of operation, the Sandusky Pilot Faci-
lity retained 59% of the overflow which would have normally
been discharged directly to Lake Erie. Overflows from the
facility occurred approximately 1% of the time. By applying
the 80% factor for sanitary sewage and 20% factor for storm
water, the Sandusky Pilot Facility and combined sewer system
contained over 90% of the pollution load and delivered it
for treatment at the water pollution control station.
Aesthetics
One of the items to be considered in the evaluation of the
127
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pilot facility was the aesthetics relationship with the
surrounding area. Figure 13 showing the McEwen Street
outfall speaks for itself. While doing preliminary in-
vestigations , strong odors were present many times in the
area of this outfall. After installation of the pilot
facility, no odors were noticed.
While the pilot facility control building and fencing fits
into the area, the underground prebuilt pump station for
future installations should blend with any existing housing
scheme. The underwater tanks as well as underground tanks
also tend to fit easily into any existing housing scheme.
128
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SECTION IX
ACKNOWLEDGEMENTS
It has required the support and kind assistance of many in-
dividuals and organizations to make this project possible.
The following acknowledgements are only a few of those to
whom we are sincerely grateful.
This project could not have been possible without the fund-
ing and support of the Water Quality Office, Environmental
Protection Agency. Assistance and direction were provided
by the division of Applied Research and Development through
Mr. Allen Cywin; the Storm and Combined Sewer Pollution
Control Branch through Mr. William A. Rosenkranz, Chief, and
Mr. George A. Kirkpatrick, Project Officer; and the Procure-
ment Branch through Mr. Robert L. Wright, Contracting Officer,
and Mr. John H. Blake.
The City of Sandusky through the approvals by the City
Commission and assistance provided by Mr. Paul A. Flynn, past
City Manager and the late Mr. William R. Donahue, City Eng-
ineer proved invaluable to the project.
Bay Construction Company of Sandusky, Ohio is acknowledged
for the competent construction of the facilities.
Firestone Coated Fabrics Company of Magnolia, Arkansas, is
acknowledged for supplying information and rubber fabric
for the tanks.
The State of Ohio, Department of Health is acknowledged for
the assistance and approvals provided.
Acknowledgement is made for the assistance by various members
of the firm throughout the project.
Mr. Syed M. Nehal who made outstanding professional engineer-
ing contributions in many aspects of the project.
Mr. Harold L. Laurila whose able assistance in the construc-
tion and operation phases was invaluable.
Mr. James F. Forsythe who provided the electrical engineering
for the facility.
Karl R. Rohrer
William J. Bandy, Jr.
129
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SECTION X
AWARDS
With F.W.P.C.A. approval, Rohrer entered the demonstration
pilot facility in the Ohio Society of Professional Engi-
neer's program, "The Seven Engineering Wonders of Ohio" for
1968. On January 23, 1969, Rohrer was notified that the
Sandusky Pilot Facility had been chosen as one of the final
choices for this annual award by the Ohio Society of Pro-
fessional Engineers.
On January 19, 1970, Rohrer was again notified that the
Sandusky'Pilot Facility had been selected as one of the
outstanding engineering achievements for 1969 by the Na-
tional Society of Professional Engineers. Entrance of
State award winners into this program is automatic.
131
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SECTION XI
PATENTS
On behalf of the U.S. Department of the Interior, Federal
Water Pollution Control Administration, and Karl R. Rohrer
Associates, Inc., Rohrer has applied for patent rights for
the underwater pilot demonstration facility-
The Underwater Tank System patent was issued on March 30,
1971 numbered U.S. Patent No. 3,572,506.
The Automatic Sampling Device patent was issued on June
28, 1971 as U.S. Patent No. 3,587,324.
133
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SECTION XII
BIBLIOGRAPHY
1. American Institute of Steel Construciton, Inc.
Manual of Steel Construction. (4th revised
printing of 6th ed.)1967.
2. Anderson, R.J.; Weibel, S.R.; and Woodward, R.L.
"Urban Land Runoff As a Factor in Stream Pollu-
tion." Water Pollution Control Federation Jour-
nal, Volume 36, No. 7. July, 1964.
3. Bauer, William; Dalton; Frank; and Koelzer, Victor.
The Chicagoland Deep Tunnel Project. The Metro-
politan Sanitary District of Greater Chicago.
September,1968.
4. Benzie, W.J. and Courchaine, R.J. "Discharges From
, Separate Storm Sewers and Combined Sewers."
Water Pollution Control Federation Journal, Vol-
ume 38, No. 3 March, 1966~
5. Borgman, L.E. and Brown, L.J. Tables of the Statis-
tical Distribution of Ocean Wave Forces and
Methods of Estimating Drag and Mass Coeff. U.S.
Army Coastal Engineering Research Center, Tech.
Memorandum No. 24. AD 662-056. October, 1967.
6. Brater, E.F. Wave Forces on Submerged Structures.
Journal of the Hydraulics Division. Proc. Paper
1833. Proc. of A.S.C.E. November, 1958.
7. Doeringsfeld, H.A. and Miller, F.E. Mechanics of
Materials. 2nd ed. Scranton, Pa. (3rd printing)
June, 1965.
8. Erie Regional Planning Commission. Existing Land Use,
City of Sandusky. September, 1965.
9. Erie Regional Planning Commission. Housing, City of
Sandusky. March, 1965.
10. Erie Regional Planning Commission. Industrial Land
Use. October, 1965.
12. Erie Regional Planning Commission. The Sandusky Water-
front. July, 1965.
135
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13. Hittman Associates, Inc. The Beneficial Use of Storm
Water Final Report. HIT 344. August, 1968.
14. Klashman, Lester M. and Romer, Harold. U.S. Department
of Health, Education, and Welfare, Public Health
Service. "How Combined Sewers Affect Water Pol-
lution, "Public Works Magazine. March and April,
1963.
15. The James F. Lincoln Arc Welding Foundation. Design
of Welded Structures. June, 1966.
16. Munk, W.H. Wave Action on Structures. American Insti-
tute of Mining and Metallurgical Engineering.
Tech. Pub. No. 2322. March, 1948.
17. Ohio Department of Health, Division of Engineering.
Summary of Municipal Sewage Treatment Works in
Ohio. January, 1968.
18. Roark, R. Formulas for Stress and Strain. McGraw-Hill
Book Company. New York, 1954.
19. City of Sandusky, Ohio. Water Pollution Control En-
gineering Data for Secondary Treatment from
Sandusky and Erie County Sanitary Sewerage Dis-
tricts .A report prepared by Bonham, Grant and
Brundage, Limited. Columbus, Ohio, 1968.
20. Timoshenko, S.D. and Young, D.H. Theory of Structures.
2nd ed. McGraw-Hill, Inc. 1965.
21. U.S. Department of the Army. Corps of Engineers. Lake
Survey District. Great Lakes Ice Cover Winter
1964-65. U.S. Lake Survey Research Report No. 5-1.
December, 1965.
22. U.S. Department of the Army, Corps of Engineers, U.S.
Lake Survey. Great Lakes Pilot 1966. U.S. Gov-
ernment Printing Office.1966.
23. U.S. Department of the Army, Office of the Chief of
Engineers. Engineering and Design. Design of
Breakwaters and Jetties. Engineers Manual, EM
1110-2-2904. 30 April 1963.
24. U.S. Department of the Army, Office of the Chief of
Engineers. Engineering and Design. Working
Stresses for Structural Design. Engineers Man-
ual, EM 1110-1-2101. L November, 1963.
136
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25. U.S. Department of Health, Education, and Welfare, Pub-
lic Health Service. A Preliminary Appraisal -
Pollutional Effects of Stormwater and Overflow
from Combined Sewer SystemsTPublic Health Ser-
vice Publication No. 1246. November, 1964.
26. U.S. Department of the Interior, Federal Water Pol-
lution Control Administration, American Public
Works Association. Problems of Combined Sewer
Facilities and Overflow 1967.Water Pollution
Control Research Series No. WP-20-11. December 1,
1967.
27. U.S. Department of the Interior, Federal Water Pol-
lution Control Administration. Great Lakes Reg-
ion . Lake Erie Report, A Plan for Water Pollution
Control. August, 1968.
28. U.S. Department of the Navy. Bureau of Supplies and
Accounts. Office of Naval Research Contract.
U.S. Rubber Company. Final Report Development of
a 50,000 Gallon Submersible Fuel Cache. Monr.-
2957 (00). Task No. NT-F015-05-001. Underwater
Fuel Cache. December, 1960.
29. U.S. Department of the Navy. Corps of Engineers. U.S.
Army Coastal Engineering Research Center. Shore
Protection, Planning and Design. 3rd ed. Techn.
Report No. 4. 1966.
30. Wiegel, Robert L. Model Study of a Submerged Buoyant
Tank in Waves. Institute of Engineering Research.
Wave Research Laboratory. Tech. Report Series 91,
Issue 4. University of California. 31 March 1956.
31. Wiegel, Robert L. Model Study of a Submerged^Buoyant
Tank (MK II) In WavesTInstitute of Engineering
Research. Wave Research Laboratory. Tech. Report
Series 91, Issue 5. University of California.
September, 1956.
32. Wiegel, Robert L. Oceanographical Engineering. Inter-
national Series in Theoretical and Applied Mathe-
matics. Prentice-Hall 1964.
137
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33. Wilson, B.W. Results of Analysis of Wave Force Data
Confused Sea Condition Round a 30 Inch Test Pile
- Gulf of Mexico. The A & M College of Texas,
Department of Oceanography and Meteorology.
A & M Project 55. Ref: 57-21F Final Tech. Report
No. 55-7. July, 1957.
138
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SECTION XIII
GLOSSARY
COMBINED SEWER - A sewer which carries sanitary sewage with
its component commercial and industrial wastes at all times
and which during storm or thaw periods serves as the col-
lector and transporter of storm water from streets or other
sources; thus, serving a "combined" purpose. Combined Pewers
make provision for the overflow of excess amounts of flow
from the combined system to points of discharge.
COMPLETE SEWER SEPARATION - Separation of all public com-
bined sewers into two separate and independent sewer systems,
one for the handling of sanitary sewage and industrial and
commercial wastes and the other for the handling of storm
water flow.
DRAINAGE BASIN - A geographical area or region which is so
sloped and contoured that surface runoff from streams and
other natural watercourses is carried away by a single drain-
age system by gravity to a common outlet or outlets; also
referred to as a Watershed or Drainage Area.
FREQUENCY OF STORM ( DESIGN STORM FREQUENCY ) - The antici-
pated period in years, which will elapse, based on average
probability of storms in the design region, before a storm
of given intensity and/or total volume will recur; thus, a
10 year storm can be expected to occur on the average once
every 10 years. Sewers designed to handle flows which occur
under such storm conditions would be expected to be sur-
charged by any storms of greater amount or intensity.
GAS VENT VALVE - Valve to release entrained or evolved gases
from interior of underwater storage tanks.
IN-SYSTEM STORAGE - Facilities or the capacity for holding or
retaining of flows of sewage and other wastes in subterran-
ean storage chambers or other portions of the sewer system
in order to minimize overflows from combined sewers and per-
mit the treatment of large volumes of such flows.
INTERCEPTION RATIO - Pertaining to combined sewer regulators,
it is the ratio of the maximum flow which can be directed to
the interceptor sewer to the normal dry weather flow.
139
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INTERCEPTOR SEWER - A sewer which receives dry-weather flows
from a combined collection sewer system and pre-determined
additional amounts of storm flow by means of any form of re^-
gulating device and then conducts these flows to point of
treatment or discharge. The flow not intended to be so con-
ducted then overflows to receiving waters.
LIMITED BODY CONTACT RECREATION - Use of natural waters, such
as rivers, lakes, and coastal waters, for recreational pur-
poses which do not represent deliberate or planned total
body immersion such as swimming or bathing; thus, use of wat-
ers for boating, fishing, and related sports.
OFF-SYSTEM STORAGE - Facilities for holding or retaining ex-
cess flows from combined sewers, over and above the carrying
capacity of the interceptor sewers, in chambers, tanks,
lagoons, ponds, or other basins which are not a part of the
subsurface sewer system.
OVERFLOW - The excess flow from combined sewers which is
not conveyed to the plant for treatment but is transmitted
by pipe or other channel directly to the receiving waters.
PRESSURE RELIEF VALVE - Protective relief valve preset to
prevent overfilling of underwater storage tanks in case of
control valve failure.
PRIMARY TREATMENT - Processes or methods, that serve as the
first stage treatment of sewage and other wastes intended
for the removal of suspended and settleable solids by gravity
sedimentation; provides no changes in dissolved and colloidal
matter in the sewage or wastes flows.
REGULATOR - A structure installed in a canal, conduit, or
channel to control the flow of water or wastewater at intake,
or to control the water level in a canal, channel, or treat-
ment unit. A device for regulating the diversion of flow in
combined sewers. A device for regulating water pressure.
SANITARY SEWAGE - Wastewater discharged from homes, commer-
cial establishments , and other structures; designated as
"sanitary" flow because it is composed of used or spent water
resulting from human use in so-called sanitary conveniences.
SANITARY SEWER - A sewer that carries liquid and water-
carried wastes from residences, commercial buildings, in-
dustrial plants, and institutions, together with minor
quantities of ground, storm, and surface waters that are
not admitted intentionally.
140
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SECONDARY TREATMENT - Processes or methods for the supple-
mental treatment of sewage and other wastes, usually follow-
ing primary treatment, to effect additional improvement in
the quality of the treated wastes by biological means of
various types, including activated sludge treatment or tick-
ling filter treatment; designed to remove or modify organic
matter.
SEDIMENTATION CHAMBER - Chamber used to control solids with-
in underwater storage tank and allow pumping liquid and
solids.
SEWAGE PUMPING STATION - An installation that pumps or lifts
sewage and other wastes from a lower level in a sewer system
into a higher sewer or a receivd ng chamber for transportation
to a treatment plant or point of discharge.
STATIC REGULATOR - A regulator which has no moving parts or
has movable parts which are insensitive to hydraulic condi-
tions at the point of installation and which are not capable
of adjusting themselves to meet varying flow or level condi-
tions in the regulator - overflow structure.
STORM WATER - The excess water running off from a surface of
a drainage area during and immediately after a period of rain.
It is that portion of the rainfall and resulting surface
flow that is in excess of that which can be absorbed through
the infiltration capacity of the surface of the basin.
STORM SEWER - A sewer that carries storm water and surface
water, street wash and other wash waters, or drainage, but
excludes domestic wastewater and industrial wastes. Also
called storm drain.
TIDE GATE ( BACKWATER GATE ) - A gate installed at the end
of a drain or outlet pipe to prevent the backward flow of
water or wastewater. Generally used on sewer outlets into
streams to prevent backward flow during times of flood or
high tide.
WATER POLLUTION CONTROL PLANT - An arrangement of devices
and structures for the control of waterborne pollution of
waterways. Also referred to as treatment plant, with
appropriate adjective describing source of wastewater.
WET-WEATHER TO DRY-WEATHER RATIO - An "indicator" of the
capacity of an interceptor sewer, as designed to carry the
higher flows resulting from periods of storm, compared to
the capacity provided by design to handle flows during dry
141
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weather. In an interceptor sewer, the additional wet-
weather flow capacity makes it possible for the sewer to
carry a predetermined amount of storm water admixed with
sanitary flows to the point of ultimate treatment or dis-
posal. Excess storm water is permitted to flow directly
into receiving waters at overflow points in the collection
sewer system.
142
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SECTION XIV
ABBREVIATIONS
F.W.P.C.A. Federal Water Pollution Control Admin-
istration, a department of the United
States Department of the Interior.
Rohrer Karl R. Rohrer Associates, Inc.
T.L.C.S. Tank Level Control System, system used
on the underwater storage system to
monitor tank volume and to operate the
automatic control valves on the influ-
ent lines to the underwater storage
tanks.
1955 I.G.L.D. 1955 International Great Lakes Datum,
Elevations in feet above mean water
level at Father Point, Quebec.
BOD Five Day Biochemical oxygen demand.
(B.O.D.)5
COD Chemical oxygen demand
DO Dissolved oxygen
TS Total solids
TSV Total solids volatile
SS Suspended solids
SSV Suspended solids volatile
ml Milliliters
mg/1 Concentration in milligrams per liter
cfs Flow rate, cubic feet per second
mgd Flow rate, million gallons per day
gpd Flow rate, gallons per day
gpm Flow rate, gallons per minute
143
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gpcd Gallons per capita per day
DWF Dry weather flow
in/hr Intensity of rainfall-inches per hour
psi Pounds per square inch
144
-------
SECTION XV
APPENDICES
Page
1. Discharge Into Flexible Underwater
Tanks 147
2. Physical and Chemical Properties
Of Neoprene Coated Nylon Fabric 151
3. Water Quality Criteria 161
145
-------
DISCHARGE INTO FLEXIBLE UNDERWATER TANKS
Dr. A.L. Simon
Chairman Department of Civil Engineering
College of Engineering
University of Akron
Akron, Ohio
1967
147
-------
DISCHARGE INTO FLEXIBLE UNDERWATER TANKS
Equations given below are made on the basis of model exper-
iments by Rohrer. If there is no tank at the end of the
pipe, the formula for Qgpm is:
(1) Q = A C (2g h)V2
Where: Ap is the area of the pipe,
C is .303 for the pipe used, and
h is the hydrostatic head.
If there is a flexible tank at the end of the pipe, then
formula (1) is to be multiplied by a coefficient 3 (bag
coefficient). For the different bags tested in the lab-
oratory 6 is as follows:
Rohrer Tank = .974
appears to depend on the following:
Pillow Tank = .900
a.
b.
c.
d.
Size of the bag,
Shape of the bag,
Stiffness of the bag, and
Relative depth of the bag under water level (expressible
as depth/smaller width of tank).
The two bags tested were different in all of these conditions.
Hence, the relative influence of the conditions on B can not
be determined. However, testing of full scale bags under
field conditions will give g sufficiently to be used in design.
Direct translation of 8 by model scale is inadvisable now.
The experiments indicate that the rate of filling decreases
as the bag fills. The following formula expresses this for:
(2) X = [a -
b t
T
V
TQ
In this equation Q is the inflow discharge into the bag
(gpm) at t, "a" and "b" are constants, t is the time of
filling from start (minutes), T is the total filling time
(minutes), V is the total volume of the tank under water
(ft3). X is the ratio of Q (initial) /Q (actual) at t.
Experimental results indicate the following values for "a1
and "b":
a =.1135
b + .028
148
-------
Theoretical explanations for equation (2) would be based
on concepts of underwater jet dynamics, theories of turbu-
lence, elastic instability of membrane stresses, and the
virtual mass theory of fluid dynamics.
However, the magnitude of "b" shows that the time dependent
variation of the discharge is of the order < 3% of Q
average - insignificant under field conditions.
Conclusions
1. The type of the bag has an influence on the rate of
inflow ranging to about 10% of unhindered inflow for the
pillow tank.
2. The Rohrer bag design seems to have much better hy-
draulic characteristics as far as the inflow in concerned,
having a decreasing effect on the inflow of 2.6% only.
3. The variations of inflow due to the gradual stiffening
of the filling tank is only about 3%. Under field conditions
where wave actions are present this may change significantly.
149
-------
PHYSICAL AND CHEMICAL PROPERTIES OF
NEOPRENE COATED NYLON
FABRIC
151
-------
In fabridam installations, the working stress allowed in
the fabric is usually limited to approximately 400 pounds
per linear inch, since the fabric is exposed in such in-
stallations to the atmosphere elements such as ultra-violet
rays from the sun and ozone from the air which cause weather-
ing of the fabric.
Figures 40 and 41 show test results for two-ply and one-ply
neoprene rubber coated 13 ounce nylon fabric. The two-ply
fabric is that used in the construction of the underwater
storage tanks. The one-ply fabric is given to show the com-
parison in fabric strength. Possible us<= of this tank is
anticipated if the water depth over the tank site were suf-
ficent to allow a higher profile tank design or if internal
tank pressure could be held between 0 and 0.25 psi.
Figure 42 shows the temperature ranges in which similar
neoprene rubber coated fabric can be used in Fabri-tank
installations. The wide range of temperatures will not be
of as much importance in the underwater environment as the
immersion of the fabric in water for ten and twenty year
periods.
Prior to this project, neoprene rubber coated nylon fabric
had not been used to any extent in contact with sewage.
Little past experience could be cited for sewage applica-
tions and therefore not much is known of the chemical
resistance to sewage for this particular fabric.
The physical and chemical composition of sewage varies
greatly from site to site. Municipal and industrial
wastes may contain certain compounds harmful to the neo-
prene rubber coated fabric. Tests of the liquid must be
made to insure that special coatings are not necessary.
However, due to the dilution of the storm water and to
the residential type drainage area, possible damaging
chemicals were negligible in the Sandusky, Ohio pilot fac-
ility area.
Table 14 shows those materials which have been tested by
the Firestone Coated Fabrics Company to determine if the
neoprene rubber coated fabric is resistant.
152
-------
The rubber fabric used for the two underwater storage tanks
w&s furnished by Firestone Coated Fabrics Company, Division
of Firestone Tire and Rubber Company.
General specifications for the rubber fabric were:
The material is to be a rubber fabric
consisting of two-ply 13 ounce nylon,
square woven, neoprene coated fabric
with an ultimate tensile strength of
1,400 pounds per linear inch warp and
fill. This material is to be supplied
in 62 feet square pieces with marking
lines provided for clamping locations
and rolled on a mandrel to facilitate
unloading and placing without damage
to the fabric.
Mr. M.M. Yancy of Firestone Coated Fabrics Company super-
vised installation of the fabric during installation to the
tank frames.
The stress bearing component of the neoprene rubber coated
fabric is the nylon fabric. Neoprene base compounds have
been chosen because their weathering characteristics are
excellent and the life expectancy of the fabric has been
determined to be in the neighborhood of twenty years in
Imbertson Fabridam installations.
Fabridam material similar to that used in the underwater
storage tanks has the following physical properties:
Construction Wt. Per Puncture Resis- Ultimate Breaking
Sq . Yd. tance in # Strength #/lin.in.
2-ply hvy.
duty 8.3 Ibs. 370 1400
The test used in measuring puncture resistance is per spec.
MIL-T-6396 B.
The abrasive resistance of fabridam construction has been
excellent. During a six month test of vibrating a rubber
coated fabric sample in a box with a mixture of sand,
gravel, and water, no appreciable wear was detected. The
rubber coatings have been accepted as standard protective
liners and covers for internal parts of sand blasting, grit
blasting, and similar abrasive inducing equipment.
153
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JU28
IE
UJ
o. 24
z
§20
P
i
12
200 460 600 800 1000
LOAD IN POUNDS PER LINEAR INCH
1200
I40C
TWO - PLY NEOPRENE COATED
13 OZ. NYLON FABRIC
FIRESTONE COATED FABRICS COMPANY
KARL R. RQHRER ASSOCIATES ,INC.
AKRON, OHIO
FIGURE 40
154
-------
0 100 200 300 400 900 600 700 800
LOAD IN POUNDS PER LINEAR INCH
SINGLE-PLY NEOPRENE COATED
13 OZ. NYLON FABRIC
FIRESTONE COATED FABRICS COMPANY
KARL R. ROHRER ASSOCIATES , INC.
AKRON , OHIO
FIGURE 41
155
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SOLID LINES OPERATING AND HANDLING
BROKEN LINES DORMANT (FILLED OR STORED)
200°-
190°-
160°-
150°-
125*
100'
50«
32 <
ZERO*
-20°-
-40°-
-50°-
-70«-
NEOPRENE
f_
FAHRENHEIT SCALE
FABRITANK USE TEMPERATURE RANGE
FIRESTONE COATED FABRICS COMFttNY
KARL R. ROHRER ASSOCIATES , INC.
AKRON, OHIO
FIGURE 42
156
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TABLE 14
FABRITANK POLYMERS
Firestone Coated Fabrics Company
Revised 11/10/64
Type Material
NP Neoprene
Chemical
Group
Chloroprene
Trade or General
Popular Name Use '
GR-M
Neoprene
Process
Water,
Near Neutral
Fertilizer
Solutions,
Moderate
Chemicals
FABRITANK CONTAINERS
Chemical Resistance
Revised 7/24/64
R - Resists - Tank is suitable for containing the indicated
material.
NR - Not Resistant - Tank is not suitable for containing
the indicated fluid.
Notes: (a) Initial discoloration of fluid may take
place.
(b) Taste of contained fluid may be affected.
157
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Table 14 Continued
Material Concentration NP
Acid, Acetic Up to 80% NR
Acid, Boric R
Acid, Chromic Any NR
Acid, Citric (not potable) Any R
Acid Hydorchloric Any NR
Acid, Lactic (not potable) Any R
Acid, Oleic NR
Acid, Phosphoric, Cold Up to 60% NR
Acid, Sulfuric Any NR
Acid, Tartaric (not comestible) R
Acid, Tannic - to 10% Any R
Acetone NR
Alums of Ammonia R
Alums of Chromium NR
Alums of Pottassium R
Ammonium Chloride R
Ammonium Phosphate, Mono, Di, Tri R
Ammonium Sulfate R
Amyle Alcohol R
Aniline NR
ASTM Oils 1, 2, & 3 NR
Asphalt Emulsions R
Asphalt (160 to 180°F) NR
Barium Chloride R
Barium Hydroxide R
Barium Sulfate R
Beet Sugar Liquors R (b)
Benzene NP
Borax R
Butadience Styrene (SBR) Latex R
Bunker C Fuel Oil (160° - 180° F) NR
Calcium Acetate R
Calcium Bisulfite R
Calcium Chloride R
Calcium Hydroxide R
Calcium Nitrate R
Cane Sugar Liquors - (Not Comestible) R
Carbon Tetrachloride NR
Castor Oil - (Not Comestible) NR
Chlorinated Solvents NR
Chrome Plating Solutions NR
Cocoanut Oil - (Not Comestible) R (a)
Copper Sulfate R
Creosote, Coal Tar NR
Crude Oil, Sour NR
Denatured Alcohol (Methanol) R (a)
158
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Table 14 Continued
Material Concentration NP
Diesel Fuel NR
Decalin NR
Dibutrl Phthalate NR
Diethylene Glycol R (a)
Dimethyl Hydrazine NR
Dioctrl Phthalate NR
Dipentene NR
Dowtherm NR
Ester. Plasticizers, Monomeric NR
Ethyl Acetate NR
Ethyl Alcphol (Ethanol) R (a)
Ethylene Glycol R (a)
Fatty Acids NR
Formalin to 37% R
Gasoline, Automotive NR
Gasoline, Aircraft NR
Gelatin (Not Comestible R
Glucose (Not Comestible Any R
Glycerol R (a)
n-Hexane NR
Hydrazine Any NR
Halowax Oil NR
Kerosene R
Ketones as a Class NR
Latex - FRS R
Latex - Hevea R
Linseed Oil NR
Methyl Alcohol R (a)
Mesityl Oxide NR
Mineral Spirits NR
Motor Oil NR
Naptha, VM & P NR
Nickel Chloride R
Nickel Sulfate R
Nitro Parafins NR
Olive Oil (Not Comestible) NR
Peanut Oil (Not Comestible) NR
Phenol, Liquid Any NR
Pine Oil, if flash point exceeds 80° F NR
Pine Oil NR
Potassium Acetate Any R
Potassium Chloride Any R
Potassium Sulfate Any R
Propyl Alcohol R (a)
Salt Water R
Sewage
159
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Table 14 Continued
Material Concentration NP
Shell Sol 140 NR
Skelly Solve, B,C,E, NR
Skydrol 500 NR
Sodium Chloride Any R
Sodium Sulfate Any R
Styrene NR
Sucrose Solutions (Not Comestible) R
Sulfur R
Tetralin NR
Toulene NR
Transformer Oil to 160°F NR
Turpentine NR
Tricreyl Phosphate NR
Urea - Formaldehyde Resins, Liquid R (a)
Water - Brine Process, Beverage (Not Potable) R
Water, Process R
Water, Potable R (b)
Xylene NR
160
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WATER POLLUTION CONTROL BOARD
DEPARTMENT OF HEALTH
COLUMBUS, OHIO
Water Quality. Criteria Adopted by the Board April 11, 1967
For Lake Erie and The Interstate Waters Thereof
The Ohio Water Pollution Control Board hereby adopts the
following water quality criteria for Lake Erie and the
interstate waters thereof which may affect the State of
Michigan, the Commonwealth of Pennsylvania, the State of
New York, and the Province of Ontario of the Dominion of
Canada.
Water Quality - Conditions and Criteria
All. Waters. All the waters considered herein shall meet
the following conditions at all times:
1. They shall be free from substances attributable to
municipal, industrial, or other discharges that will settle
to form putrescent or otherwise objectionable sludge depo-
sits;
2. They shall be free from floating debris, oil, scum,
and other floating materials attributable to municipal, in-
dustrial or other discharges in amounts sufficient to be un-
sightly or deleterious;
3. They shall be free from materials attributable to muni-
cipal, industrial, or other discharges producing color, odor,
or other conditions in such degree as to create a nuisance;
and,
4. They shall be free from substances attributable to
municipal, industrial, or other discharges in concentra-
tions or combinations which are toxic or harmful to human,
animal, plant, or aquatic life.
Lake Erie Water Quality Criteria for Various Uses are: (1)
the Stream-Water Quality Criteria for Various Uses adopted
by the Ohio Water Pollution Control Board on June 14, 1966
161
-------
copy attached, which shall apply as a minimum to all Lake
Erie waters in Ohio, and (2) the existing lake water qual-
ity which shall apply, where better than, the criteria for
streams adopted by the Board. The existing lake water
quality shall be as reported by the Federal Water Pollution
Control Administration in the chapter on Water Quality in the
report "Program for Water Pollution Control - Lake Erie-
1967."
Lake Erie outside the established harbors at Lorain, Cleve-
land and Ashtabula shall meet the Lake Erie Quality Crit-
eria for all uses.
The Lorain, Cleveland, and Ashtabula harbor waters in Lake
Erie shall meet the Lake Erie Quality Criteria for indus-
trial water supply and aquatic life. (A).
Implementation and Enforcement Plan
The Ohio Water Pollution Control Board, under the pro-
visions of Sections 6111,01 to 6111.08, 6111.31 to 6111.38,
and 6111.99. Ohio Revised Code, has authority to control,
prevent, and abate pollution in the waters of this state.
In accordance with such authority, the Board hereby adopts
the following program and requirements for the prevention,
control, and abatement of new or existing pollution of the
waters of Lake Erie.
1. The "Recommendations and Conclusions - August 12,
1965" agreed upon by the conferees from Michican, Indiana,
Ohio, Pennsylvania, New York, and the U.S. Public Health
Service following a conference under Section 8 of the Federal
Water Pollution Control Act in the matter of pollution of
the interstate and Ohio intrastate waters of Lake Erie and
its tributaries held in Cleveland, Ohio, August 3-6, 1965,
and in Buffalo, New York, August 10-12, 1965, and "Report
of the Lake Erie Enforcement Conference Technical Committees
-March, 1967" are included as a part of this program insofar
as applicable to Lake Erie waters in Ohio;
2. All plans and proposals for abatement or correction of
pollution will be approved by the Ohio Department of Health
as required by law and such approvals shall constitute ap-
proval by the Board;
3. All sewage will be given secondary treatment (biochemical
oxidation), and the facilities to provide such treatment
162
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be constructed and placed in operation without delay,
and in no instance later than the dates specified in the
attached lists;
4. All effluents will be satisfactorily disinfected to
meet the criteria for Lake Erie water uses and the facili-
ties to provide such disinfection will be installed without
delay;
5. All industrial wastes will be adequately treated to
meet the Lake Erie water quality conditions and criteria
and the facilities to provide such treatment will be con-
structed and placed in operation without delay, and in no
instance later than the dates specified in the attached
lists;
6. Local programs will be initiated to control and reduce
pollution resulting from (a) bypassing, (b) spillages, and
(c) discharges resulting from construction or breakdowns;
7. Necessary studies will be made and, where feasible,
plans and construction programs will be developed as rapid-
ly as possible for reducing pollution from combined sewer
overflows;
8. Where necessary to improve water quality and to reduce
algal growths in Lake Erie, supplementary treatments of
waste-waters will be provided to the fullest extent con-
sistent with research and technological advances;
9. Where necessary to protect recreational areas of Lake
Erie, studies will be made by the responsible agencies, and
plans and construction programs will be developed as rapid-
ly as possible for improvements such as (a) elimination,
treatment or diversion of combined and storm sewer discharges
from beaches and other recreational areas, (b) diversion of
all effluent discharges, both sewage and industrial wastes,
from areas where they may adversely affect recreational
waters, and (c) elimination of the physical entrapment of
storm water, marsh drainage, debris, and other pollutants
at beach areas;
10. The Lake Erie water quality monitoring program will be
expanded as outlined in the attached report to_adequately
provide assurances of compliance with these criteria.
Furthermore, the Board and the Ohio Department of Health
will:
163
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1. Encourage and assist other agencies such as the Ohio
Water Commission and the Soil Conservation Service, U.S.
Department of Agriculture, in the implementation of effec-
tive soil erosion control programs, and programs for the
reduction of the run-off of phosphorous, nitrogen compounds,
and pesticides;
2. Encourage the enactment of State legislation prohibit-
ing the discharge of untreated wastewater from pleasure
craft to the Lake Erie waters in Ohio, and requiring ade-
quate waste disposal facilities at marina along Lake Erie;
and,
3. Seek adequate legislation prohibiting the open dumping
of garbage, trash, and other deleterious refuse along the
shores of Lake Erie.
Enforcement of these requirements will be carried out by
means of the respective permits issued to municipalities,
counties, industries, and other entities discharging to the
Lake Erie waters of Ohio considered herein, and failure to
comply with the permit conditions will result in legal ac-
tion in accordance with the provisions of laws.
164
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WATER POLLUTION CONTROL BOARD
OHIO DEPARTMENT OF HEALTH
COLUMBUS, OHIO
Resolution Regarding Amended Criteria of Stream-Water Qua-
lity For Various Uses Adopted by the Board on October 1,
1967. ~
WHEREAS, Section 6111.03, of the Ohio Revised Cede, pro-
vides, in part, as follows:
"The water pollution control board shall have
power:
(A) To develop programs for the prevention, con-
trol and abatement of new or existing pollution
of the waters of the state;
and
WHEREAS, Primary indicators of stream-water quality are
needed as guides for appraising the suitability
of surface waters in Ohio for various uses; and
WHEREAS, The stream-water quality criteria for various uses
and minimum conditions applicable to all waters
adopted by the Board on June 14, 1966, have been
amended by the Ohio River Valley Water Sanitation
Commission;
THEREFORE BE IT RESOLVED, That the following amended stream-
water quality criteria for various uses, and mini-
mum conditions applicable to all waters, are here-
by adopted in accordance with amendments of the
Ohio River Water Sanitation Commission.
Minimum Conditions Applicable to All Waters at All Places
and At All Times
1. Free from substances attributable to municipal, indust-
rial or other discharges, or agricultural practices
that will settle to form putrescent or otherwise ob-
jectionable sludge deposits.
2. Free from floating debris, oil, scum and other float-
ing materials attributable to municipal, industrial,
or other discharges, or agricultural practices in am-
ounts sufficient to be unsightly or deleterious.
16 S
-------
3. Free from materials attributable to municipal, indust-
rial or other discharges, or agricultural practices
producing color, odor or other conditions in such de-
gree as to create a nuisance.
4. Free from substances attributable to municipal, indus-
trial or other discharges, or agricultural practices in
concentrations or combinations which are toxic or harm-
ful to human, animal, plant or aquatic life.
166
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STREAM-QUALITY CRITERIA
For Public Water Supply
The following criteria are for evaluation of stream quality
at the point at which water is withdrawn for treatment and
distribution as a potable supply:
1. Bacteria: Coliform group not to exceed 5,000 per 100
ml as a monthly average value (either MPN or MF count);
nor exceed this number in more than 20 percent of the
samples examined during any month; nor exceed 20,000
per 100 ml in more than five percent of such samples.
2. Threshold-odor Number; Not to exceed 24 (at 60 deg.C)
as a daily average.
3. Dissolved solids; Not to exceed 500 mg/1 as a month-
ly average value, nor exceed 750 mg/1 at any time.
4. Radioactivity; Gross beta activity not to exceed 1,000
picocuries per liter (pCi/1), nor shall activity from
dissolved strontium-90 exceed 10 pCi/1, nor shall activi-
ty from dissolved alpha emitters exceed 3 pCi/1.
5. Chemical constituents; Not to exceed the following
specified concentrations at any time:
Constituent Concentration (mg/1)
Arsenic 0.05
Barium !-°
Cadmium 0.01
Chromium 0.05
(hexavalent)
Cyanide 0.025
Fluoride 1-0
Lead O-05
Selenium 0.01
Silver °-05
For Industrial Water Supply
The following criteria are applicable to stream water at
the point at which the water is withdrawn for use (either)
with or without treatment) for industrial cooling and pro-
cessing:
167
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1. Dissolved Oxygen; Not less than 2.0 mg/1 as a daily
average value, nor less than 1.0 mg/1 at any time.
2. pH: Not less than 5.0 nor greater than 9.0 at any
time.
3. Temperature: Not to exceed 95 deg. F at any time.
4. Dissolved solids: Not to exceed 750 mg/1 as a month-
ly average value, nor exceed 1,000 mg/1 at any time.
For Aquatic Life A
The following criteria are for evaluation of conditions for
the maintenance of a well-balanced, warm-water fish popu-
lation. They are applicable at any point in the stream
except for areas immediately adjacent to outfalls. In
such areas cognizance will be given to opportunities for
the admixture of waste effluents with stream water:
1. Dissolved Oxygen; Not less than 5.0 mg/1 during at
least 16 hours of any 24-hour period, nor less than
3.0 mg/1 at any time.
2. pH; No values below 5.0 nor above 9.0 and daily
average (or median) values preferabley between 6.5
and 8.5.
3. Temperature: Not to exceed 93 deg. F at any time
during the months of May through November, and not
to exceed 73 deg. F at any time during the months
of December through April.
4. Toxic Substances: Not to exceed one-tenth of the
48-hour median tolerance limit, except that other
limiting concentrations may be used in specific
cases when justified on the basis of available
evidence and approved by the appropriate regula-
tory agency.
For Aquatic Life B
The following criteria are for evaluation of conditions for
the maintenance of desirable biological growths and, in
limited stretches of a stream, for permitting the passage
of fish through the water, except for areas immediately
adjacent to outfalls. In such areas cognizance will be
given to opportunities for admixture of effluents with
stream water.
168
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1. Dissolved Oxygen: Not less than 2.0 mg/1 as a daily
average value, nor less than 1.0 mg/1 at any time.
2. pH; Not less than 5.0 nor greater than 9.0 at any
time.
3. Temperature; Not to exceed 95 deg. F at any time.
4. Toxic Substances; Not to exceed one-tenth of the 48-
hour median tolerance limit, except that other limit-
ing concentrations may be used in specific cases when
justified on the basis of available evidence and ap-
proved by the appropriate regulatory agency.
For Recreation
The following criterion is for evaluation of conditions at
any point in waters designated to be used for recreational
purposes, including such water-contact activities as swim-
ming and water skiing:
Bacteria: Coliform group not to exceed 1,000 per
100 ml as a monthly average value (either MPN or
MF count); nor exceed this number in more than 20
percent of the samples examined during any month;
nor exceed 2,400 per 100 ml (MPN or MF count) on
any day.
For Agricultural Use and Stock Watering
The following criteria are applicable for the evaluation of
stream quality at places where water is withdrawn for agri-
cultural use or stock-watering purposes:
1. Free from substances attributable to municipal, indus-
trial or other discharges, or agricultural practices
that will settle from putrescent or otherwise ob-
jectionable sludge deposits.
2. Free from floating debris, oil, scum, and other float-
ing materials attributable to municipal, industrial
or other discharges, or agricultural practices in
amounts sufficient to be unsightly or deleterious.
3. Free from materials attributable to municipal, indus-
trial or other discharges, or agricultural practices
producing color, odor or other conditions in such
degree as to create a nuisance.
169
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4. Free from substances attributable to municipal, indus-
trial or other discharges or agricultural practices
in concentrations or combinations which are toxic or
harmful to human, animal, plant or aquatic life.
170
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1
5
A fcex.s ion Number
n Subject Field &. Group
05D
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM .'
Organization
Karl R. Rohrer Associates, Inc.
529 Grant Street
Akron, Ohio 44311
Title
Underwater Storage of Combined Sewer Overflows
1Q Authors)
Rohrer , Karl R.
16
21
Project Designation
EPA Project
Contract No
No .
. 14-
11022 ECV.
12-143
Note
Bandy, William J.,Jr
22
Citation
Water Pollution Control Research Series - 11022 ECV 9/71
23
Descriptors (Starred First)
Water Pollution Control
Combined Sewers
Underwater Storage
Storm Overflow
25
Identifiers (Starred First)
Flexible Tank
Abstract
purpose of this study was to demonstrate off-shore underwater temporary
storage of storm overflow from a combined sewer in flexible tanks. Site selec-
tion, model testing, system design, construction, and one year's operation were
conducted under the study.
A pilot demonstration facility was constructed in Sandusky, Ohio where com-
bined sewer overflow from a 14.86-acre residential drainage area was directed to
two-100,000 gallon collapsible tanks anchored underwater in Lake Erie., The
stored overflows were pumped back to the sewer system after a storm event for
subsequent treatment. During the year's operation, a total of 988,000 gallons
of storm overflow was contained and returned for treatment.
As constructed, the facility cost was about $1.88 per gallon of storage capa-
city while future projections indicate costs of less than $0.40 per gallon pos-
sible.
Evaluation of the underwater storage system in controlling combined sewer
pollution, comparison of cost with other storage methods and other combined
sewer pollution control methods, operational difficulties and recommendations of
an improved system are included in the study report.
This report was submitted in fulfillment of Contracts 14-12-25 and 14-12-143
between Water Quality Research, Environmental Protection Agency, and Xarl R.
Rohrer Associates, Inc.
A bstractor
Will!
am
J.
Bandy
.Tr.
Institution
Karl
R. RnV
i r A r A
s c; o <-! i
ates.
T n n t
WR:IG2 (REV. JUUY 16691
WRSI C
SEND TO: WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON, D. C. 20240
* GPO: 1060-350-330
-------
Continued from inside front cover....
11022 08/67
11023 09/67
11020 12/67
11023 05/68
11031 08/68
11030 DNS 01/69
11020 DIH 06/69
11020 DES 06/69
11020 06/69
11020 EXV 07/69
11020 DIG 08/69
11023 DPI 08/69
11020 DGZ 10/69
11020 EKO 10/69
11020 10/69
11024 FKN 11/69
11020 DWF
11000
12/69
01/70
11020 FKI 01/70
11024 DDK
11023 FDD
02/70
03/70
11024 DMS 05/70
11023 EVO
11024
06/70
06/70
Phase I - Feasibility of a Periodic Flushing System for
Combined Sewer Cleaning
Demonstrate Feasibility of the Use of Ultrasonic Filtration
in Treating the Overflows from Combined and/or Storm Sewers
Problems of Combined Sewer Facilities and Overflows, 1967
(WP-20-11)
Feasibility of a Stabilization-Retention Basin in Lake Erie
at Cleveland, Ohio
The Beneficial Use of Storm Water
Water Pollution Aspects of Urban Runoff, (WP-20-15)
Improved Sealants for Infiltration Control, (WP-20-18)
Selected Urban Storm Water Runoff Abstracts, (WP-20-21)
Sewer Infiltration Reduction by Zone Pumping, (DAST-9)
Strainer/Filter Treatment of Combined Sewer Overflows,
(WP-20-16)
Polymers for Sewer Flow Control, (WP-20-22)
Rapid-Flow Filter for Sewer Overflows
Design of a Combined Sewer Fluidic Regulator, (DAST-13)
Combined Sewer Separation Using Pressure Sewers, (ORD-4)
Crazed Resin Filtration of Combined Sewer Overflows, (DAST-4)
Stream Pollution and Abatement from Combined Sewer Overflows
Bucyrus, Ohio, (DAST-32)
Control of Pollution by Underwater Storage
Storm and Combined Sewer Demonstration Projects -
January 1970
Dissolved Air Flotation Treatment of Combined Sewer
Overflows, (WP-20-17)
Proposed Combined Sewer Control by Electrode Potential
Rotary Vibratory Fine Screening of Combined Sewer Overflows,
(DAST-5)
Engineering Investigation of Sewer Overflow Problem -
Roanoke, Virginia
Microstraining and Disinfection of Combined Sewer Overflows
Combined Sewer Overflow Abatement Technology
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