USEPA
REGION V
905R90107
Example ol a
COMBINED SEWER SYSTEM
OPERATIONAL PLAN
Technical Support Section
Water Compliance Branch
June 1990
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FOREWORD
On June 23, 1986, the USEPA Region V Office issued "NPDES Permit Strategy for
Combined Sewer Systems" in an attempt to improve cxanmunity management of
combined sewers. NPDES permit conditions now require operation and
maintenance procedures by the permittee to control combined sewer overflows to
be identified and implemented. One of these permit conditions requires the
development of an operational plan, which integrates both dry and wet weather
operation of the complete wastewater treatment system. This plan is tailored
to the community's specific system and includes mechanisms and specific
procedures to ensure that: the collection and treatment systems are operated
to maximize treatment; storm water entry into the sewer system is regulated;
the sewer system storage capacity is identified and fully utilized during wet
weather; the greatest quantity of wet weather flows receive maximum possible
treatment; all dry weather flows are treated to the level specified in the
NPDES permit; and the sewerage system is adequately maintained. The con-
ceptual contents of an operational plan are outlined in "Technical Guidance
For Use In The Development Of A Combined Sewer System Operational Plan"
September 1986, which presents a menu of items that communities should
consider.
The operational plan is a unique document providing for both the preliminary
planning and the implementation of operational measures with the intent of
reducing the environmental impact of combined sewer overflow over an extended
period of time. Thus, the document is a multifaceted product which provides
direction to a community's effort to control combined overflow impacts through
an examination of the following key questions:
1. What are the strengths and weaknesses of a community's
combined sewer overflow system with regards to reducing the
extent and impact of combined sewer overflows?
2. What can be done in a non-capital intensive manner to take
advantage of the strengths and to steer around the weaknesses
of the community's system?
3. Based on extensive weather records and the knowledge of the
strengths and weaknesses of the combined sewer system, what
kind of project is necessary to completely capture low
intensity storm events?
During 1989, Region V through a contract with Science Applications Inter-
national Corporation who subcontracted with TRIAD Engineering Incorporated
developed an actual combined sewer system operational plan to use as an
example of the level of effort and detail expected in an operational plan.
East Lansing, Michigan was selected at the candidate community.
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The operational plan for East Lansing provides answers to all of the pre-
vious key questions and is also useful as an example because of the extent of
variations which can impact combined sewer overflow control including:
1. Combined sewer areas with and without the capability for insystem
storage;
2. Mainline interceptors with and without the capability to accept
additional flows;
3. An exceptional sewer maintenance program;
4. A wastewater treatment plant with the ability to revise
operations in order to accept some of the storm induced flows;
5. Administration which has to deal with impacts to and from (and
ownership by) a major university and a Township; and,
6. A large surrounding area of sanitary sewers with significant
infiltration/inflow problems.
By utilizing the strengths and by designing around the weakness of the East
Lansing Combined Sewer Overflow System, this operational plan provides the
concept for a relatively low cost system which reduces or eliminates the
combined sewer overflows from 70% of the overflow events. Additionally, the
plan provides recommendations in the administrative and maintenance areas to
enhance the effectiveness of the system's operation.
It is also noted that for the relatively complex East Lansing sewer system for
a moderate sized community of 50,000, the analysis of storm induced flows
utilizing the U.S. EPA Storm Water Management Model, Version 4.3 was the
appropriate level of analysis. For smaller communities with relatively
simpler sewer systems, a desktop hydraulic analysis may be more appropriate.
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COMBINED SEWER SYSTEM
OPERATIONAL PLAN
EAST LANSING, MICHIGAN
Prepared by the
United States Environmental Protection Agency
Region V
Chicago, Illinois
and
Science Applications International Corporation
McLean, Virginia
with
Triad Engineering Incorporated
Milwaukee, Wisconsin
July 6, 1989
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TABLE OF CONIH/IS
i. :nra»mcTicN/EXEcurivE SUMMARY 1-1
Introduction 1-1
Executive Summary 1-2
Existing Facilities 1-2
Analysis of Collection and Treatment System 1-2
Recommendations 1-3
Report Organization 1-4
2. EAST IANSING SYSTEM INVENTORY 2-1
System Components Summary 2-1
Interceptors 2-1
Combined Sewer Service Area 2-1
Separate Sewer Service Area 2-4
Wastewater Treatment Plant 2-4
Interceptors 2-4
Main Interceptor, 54-Inch Segment 2-4
Main Interceptor, 48-Inch Segment 2-8
Main Interceptor, 33-Inch Segment 2-8
Main Interceptor, 27-Inch Segment 2-9
Main Interceptor, 24-Inch Segment 2-10
Michigan State Interceptor 2-11
Harrison/Brody Dorm Interceptor 2-11
Harrison/Kellog Interceptor 2-13
Charles Road Interceptor 2-13
Combined Sewer Service Area (CSSA) 2-13
Harrison Road CSSA 2-14
Charles Street CSSA 2-16
Oriar Street CSSA 2-16
Willmarth CSSA 2-19
Separate Sewer Service Area 2-19
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TAHTK OF OCNTEMES (cent.)
Wastewater Treatment Plant 2-25
Influent Sewer 2-25
Screening 2-25
Raw Sewage Pumps 2-25
Grit Chamber 2-25
Equalization Basin . 2-25
Primary Settling Tanks 2-25
Aeration Tanks 2-27
Secondary Settling Tanks 2-27
Tertiary Treatment 2-27
Wastewater Flows 2-27
3. AEMINISTRAnVE CONTROLS 3-1
NPDES Permit Requirements 3-1
Existing Controls 3-1
City Sewer Use Ordinance 3-1
Service Contracts 3-2
Michigan State 3-3
Meridian Township 3-4
Recommendations 3-4
Administrative Changes 3-4
Pretreatment Controls 3-7
Long-Term Administrative Recommendations 3-7
4. MAINTENANCE PROGRAM 4-1
Department of Public Works 4-1
Personnel 4-1
Schedule 4-1
Sewer Flushing 4-1
Siphon Inspection 4-2
Overflow Inspection 4-2
Catch Basin Cleaning 4-2
Sewer Repairs 4-2
Street Sweeping 4-2
Record Keeping 4-3
Sewer Blockage 4-3
Recommendations 4-4
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TABLE OF GCNZXNES (cent.)
5. CONTROL STRATEGY 5-1
Potential Control Methodologies 5-1
Basis of Analyses 5-4
Dry Weather Flows 5-4
Treatment Capacity 5-4
Rainfall Analysis 5-7
Modeling of Collection System 5-9
Proposed Control Strategies 5-12
Separate Sewer Area: Wbodingham Pump Station 5-14
Separate Sewer Areas: Meridian Township/Hamilton
Pump Station Service Area 5-14.
Michigan State University (MSU) Separate Sewer Service Area. 5-16
East Lansing/Meridian Townships Separate Sewer Area
Tributary to the Main Interceptor 5-16
Willmarth CSSA 5-16
Cedar Street CSSA 5-16
Charles Street CSSA 5-19
Harrison Road CSSA 5-19
Performance of Proposed System 5-20
Operational System Requirements 5-21
High Water Control - Floodproofing 5-23
System Flow Monitoring 5-23
Conclusion 5-24
6. IMPIUffiNIATICN AND SCHEDULE 6-1
Short-^Term Actions 6-1
Long-Term Actions 6-2
Summary 6-2
111
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T.T57P OF FIGURES
Figure Page
2-1 East Lansing Conbined Sewer Service Area 2-2
2-2 East Lansing Wasbewater Collection System 2-3
2-3 100 Year Flood Boundary 2-12
2-4 East Lansing Wastewater Treatment Plant Liquid Train . . . 2-26
5-1 Wastewater Collection System Capacity 5-5
5-2 Storm Water Management Model, Ver. 4.3 (SWMM) Anal. Areas . 5-11
5-3 Wastewater Collection System Flows - 0.5 Inch Rainfall . . 5-22
6-1 Implementation Schedule 6-3
LIST OF TABLES
Table Page
2-1 Interceptor System Summary 2-5 to 2-7
2-2 Combined Collector Sewers West Harrison CSSA 2-15
2-3 Combined Collector Sewers East Harrison CSSA 2-17
2-4 Combined Collector Sewers Charles Street CSSA 2-18
2-5 Combined Collector Sewers West Oriar CSSA 2-20
2-6 Combined Collector Sewers East Ortar CSSA 2-21
2-7 combined Collector Sewers Willmarth CSSA 2-22
2-8 Separate Sewer Area Flows 2-24
2-9 WWTP Flows (MO)) for 1987 and 1988 2-28
5-1 Definition of Terms 5-2
5-2 Dry Weather Flow vs. Hydraulic Capacity 5-6
5-3 Rainfall Analysis 5-8
IV
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LIST OF TABLES (cent.)
Table
5-4
5-5
5-6
5-7
5-8
5-9
6-1
IrnDlementation Activities
Page
5-10
5-13
5-12
5-15
5-17
5-18
6-4 - 6-.
APFHOICES
1. List of Preparers
2. References
NOTE: Although the following Appendices are an important part of a
comprehensive Combined Sewer Operational Plan (CSOP), these Appendices are
strictly project specific and would not add meaning to this document which
has been produced as an example to Municipal bodies for the preparation of
a CSOP. "Therefore, although listed below, the following Appendices have not
been included as a part of this document.
3A. NPDES Permit
3B. Monitoring Program Form
3C. Sewer Ordinance
3D. MSU Service Contract
3E. Meridian Township Service Contract
4A. Maintenance Areas
4B. Wednesday/Friday Maintenance Lists
4C. Monthly Summary Work Forms
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Chapter 1
SUMMARY
PRODUCTION
Combined sewers were designed to convey wastewater and storm water in a
single conduit to the treatment plant. During wet weather, runoff enters the
collection system resulting in the discharge of storm water and wastewater to
surface water. Because of this, combined sewer overflow (CSO) continues to
be a significant source of pollution in receiving waters. This is especially
true for cities in the upper midwest, and the northeast, where combined sewer
systems were installed before the water quality impacts of CSO were under-
stood.
The options for abatement of CSO can involve significant capital costs.
Sewer separation, which often requires private property plumbing changes to
be effective, has generally been beyond the financial capabilities of many
municipalities. Facilities for storage and treatment of overflows are expen-
sive for local communities to finance. Without grant funds, these large
scale projects have generally not been implemented.
The City of East Lansing must abate CSOs to comply with federal and state
regulations. A proposed in-line storage sewer to convey and store East
Lansing CSOs proceeded to the point where plans and specifications were sub-
mitted to the Michigan Department of Natural Resources for approval and grant
funding. Because of changing regulations and shifting funding priorities,
grant funding was not obtained. The City could not proceed with the project
using only local funds.
The City then sought non-capital intensive solutions to combined sewer
overflows. In 1986 the USEPA prepared guidelines for use in the development
of a Combined Sewer System Operational Plan. The objective of this type of
plan is to evaluate existing sewers and treatment facilities to determine if
different operations during wet weather events have the potential to reduce
overflows. Unlike facilities planning, which evaluates facilities required
to meet a performance standard, the Combined Sewer Operational Plan determines
the capabilities of existing facilities to maximize reduction of overflows.
Limited new facilities may be proposed to allow the best use of existing
facilities. The combined sewer operational plan is most effective in reduc-
ing or eliminating CSOs from low intensity or low volume rainfall/runoff
events. The advantage of the operational plan is that pollutant loadings
can potentially be reduced by a city without embarking on a major capital
improvements program.
The method used to develop the combined sewer operational plan is to
examine the major components of the collection and treatment system, the
administration of the system, and the maintenance of the system. In each of
these areas, opportunities for reduction of inflow, for temporarily storing
wet weather flows, or increasing treatment capabilities are explored. Based
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on these factors, a plan to maximize capture and treatment of wet weather
flows and a schedule of activities to implement the plan is developed.
Reduced pollutant discharges are the objectives of the plan. The combined
sewer operational plan prepared for East Lansing found opportunities for in-
line storage of wet weather flows, for rerouting of wet weather flows through
an apparently under-utilized interceptor and treatment plant modifications to
provide storage of additional wastewater at the plant site.
This study was prepared by the United States Environmental Protection
Agency - Region V located in Chicago, Illinois. The Environmental Protection
Agency was assisted in this effort by Science Applications International
Corporation and Triad Engineering Incorporated. The City of East Lansing was
an active participant in this effort. The Michigan Department of Natural
Resources participated in the initial scoping of the operational plan.
The following sections summarize existing conditions and recommendations
for reducing combined sewer overflows.
EXECUTIVE SUMMARY
Existing Facilities
The City of East Lansing, Michigan, operates a system of sewers and a
treatment plant providing tertiary treatment of wastewater. About one-half of
East Lansing is served by combined sewers. There are separate sewers in the
northern and eastern parts of the city. East Lansing also provides service by
contract to Michigan State University (MSU) and Meridian Township. The East
Lansing Combined Sewer Service Area is illustrated on Figure 2-1 (page 2-2) .
There are four major combined sewer service areas (CSSA) . The three
eastern areas, Charles Street, Cedar Street, and Willmarth, drain to a single
diversion structure and overflow point. The western most area, the Harrison
Road CSSA, has three overflow points. The Main Interceptor parallels the Red
Cedar River. There is one overflow from the interceptor which is not directly
associated with a specific drainage area. Another overflow point exists at
the Brody Dorm siphon. Rebuilding of the siphon has significantly reduced or
eliminated overflows at this point. A 48-inch interceptor is owned and opera-
ted by MSU. Meridian Township has a service contract with East Lansing and
utilizes capacity in this sewer.
of the Collection
The physical features of the collection and treatment system, its
administration, and maintenance program were evaluated to determine opportuni-
ties for reducing overflows, and to understand the limitations in the system.
EPA's Stormwater Management Model, Version 4.3 (SWMM) was used to examine
probable combined sewer system performance during four rainfall events ranging
from 0.15 inches to 1.0 inches in volume, with average durations and intensi-
ties. A 0.5-inch storm event with an average intensity of 0.17 in/hr and a
duration of three hours was looked at in greater detail to determine potential
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in-line storage capacity available, overflow volumes, and maximum flow rates.
Of the 65 estimated annual combined sewer overflow events, 46 would occur as a
result of rainfall between 0.1 and 0.5 inches. Another 12 occur because of
rainfall between 0.5 and 1.0 inches. Control of these lower volume rainfall
events would provide elimination or reduction of 70 to 90 percent of the over-
flow events. The capacities of major interceptors were determined through
standard hydraulic formulas for sewers. Based on these analyses, the follow-
ing system strengths were identified:
o A major interceptor owned by MSU has apparent capacity to convey
additional wet weather flows;
o The wastewater treatment plant has capacity to treat additional
flow;
o Combined sewer collectors have capacity available for in-line
storage in the Cedar Street CSSA and West Harrison CSSA; and,
o The City has an established, well organized, maintenance program to
clean sewers and catch basins, and to identify and repair sewers
requiring rehabilitation.
The weaknesses in the system include:
o The Main Interceptor has little capacity to accept flow beyond
existing dry weather flow;
o Lack of direct administrative control over the volume or rate of
wastewater contributions from contract service areas;
o Little or no in-line storage available in East Harrison, Charles
Street, and Willmarth CSSAs; and,
o Apparent infiltration/inflow problems in separate sewer service
areas reduce both interceptor and treatment plant capacities.
RECOMMENDATIONS
The strengths and weaknesses of the system lead to the following
recommendations:
o Perform flow monitoring to confirm model predictions;
o Reduce and redirect Main Interceptor flow by diverting separate
wastewater flow to the MSU Interceptor at East Brookfield and Grand
River Avenue;
o Provide in-line storage in the combined sewer collectors in the West
Harrison and Cedar Street CSSAs;
1-3
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o Develop off-line storage for East Harrison and Charles Street CSSA;
o Direct wet weather flow from Cedar Street and Willmarth CSSAs
through a new relief sewer to the MSU Interceptor;
o Convert unused aeration basins to provide additional wet weather
storage at the treatment plant;
o Establish better authority over system users in contract service
areas; and,
o Obtain better access to existing facilities on Michigan State
property, and rights to utilize capacity in the MSU Interceptor.
REPORT ORGANIZATION
The information collected for this report along with the analysis of
data, and conclusions of the study are documented in the following chapters:
Chapter Title
2 System Inventory
3 Administrative Controls
4 Maintenance Program
5 Control Strategy
6 Implementation Schedule
1-4
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Chapter 2
EAST LANSING SYSTEM INVENTORY
The purpose of this chapter is to describe the existing wastewater system
and how it operates. The system components are summarized below and then
described in detail in the major sections of the chapter.
The City of East Lansing owns and operates combined sewers for the col-
lection of sanitary wastewater and rainfall runoff, separate sanitary sewers
collecting wastewater only, interceptor sewers, and a tertiary wastewater
treatment facility. A combination of wastewater and runoff from the combined
sewer service area (CSSA) overflows from combined sewers or the interceptor
system and is discharged by design to the Red nariar River during wet weather
conditions. Combined sewer service areas, overflow points, and interceptor
designations are illustrated on Figure 2-1. Figure 2-2 provides a schematic
of the collection system.
SYSTEM CCMPONENIS SUMMARY
Interceptors
For purposes of this operational plan, certain sewers have been desig-
nated interceptors. These interceptors are the major conveyance facilities to
the treatment plant, or from major service areas to other interceptors. The
Main Interceptor is a line which begins as a 24-inch sewer at the diversion
structure in the Willmarth CSSA. It continues east along the Red Odar River
increasing in size to a 54-inch diameter pipe before it enters the headworks
of the East Lansing Wastewater Treatment Plant. A 48-inch interceptor serves
the Michigan State University (MSU) Campus and Meridian Township east of East
Lansing. It joins the Main Interceptor west of the Brody Street siphon at the
point that the 54-inch section begins.
Three sewers serve as connections from two combined sewer service areas
to the Main Interceptor. The first is a 36-inch interceptor which conveys
flow from the western point of the Harrison Road CSSA, separate sanitary flow
originating from the Woodingham Pumping Station, and some sanitary flow from
the adjacent MSU Brody Dorm area to the Main Interceptor. The second
interceptor is an 18-inch sewer which serves a small portion of the Harrison
Road CSSA plus a portion of the campus. A 60-inch sewer conveys flows from
the Charles Street CSSA through the MSU Campus to the Main Interceptor.
Separate sanitary flow from the campus may also enter this sewer.
Combined Sewer Service Area
Four major drainage areas illustrated on Figure 2-1 are served by
combined sewers. These have the same designations given in the previous
Combined Sewer Overflow Facilities Plan prepared for the City of East Lansing.
From west to east these are designated as Harrison Road, Charles Street, rfcrigr
Street, and Willmarth CSSAs. Further subdivisions within each area are
discussed in the following sections.
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CITY OF
EAST LANSING
Michigan
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2 - 2
FIGURE M
EAST LANSING COMBINED
SEWER SERVICE AREA
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I
2-3
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Separate Sewer Service Area
There are five principal separate sewer service areas. The largest of
these is the Michigan State University Campus. The second separate service
area is the southwest portion of East lansing, west of the MSU campus. An
area of East Lansing to the north of the Harrison CSSA, and an area to its
east in Meridian Township comprise the third area. A fourth area is the area
of East Lansing east of the Willmarth CSSA. The fifth area is the area served
by Meridian Township which is located to the east of East Lansing.
Treatment Plant
The Treatment Plant makes up the final component of the collection and
treatment system. The City of East Lansing operates a tertiary treatment
plant which has primary settling, activated sludge secondary treatment, and
dual media filtration for tertiary treatment. Solids are incinerated and
disposed of at the plant site.
The interceptor system, as defined for this plan, consists of several
large diameter sewers which convey wastewater to the treatment plant. Large
diameter sewers within the combined sewer service area and larger diameter
sanitary sewers are referred to in this report as collectors. Included in
this listing are sewers which connect the major combined sewer drainage areas
to the Main Interceptor system. A summary listing of segments of the inter-
ceptor system is provided in Table 2-1.
Main Interceptor. 54-Inch Segment
The Main Interceptor is the key conveyance facility for East Lansing.
Capacity in this sewer determines the volume of wastewater which can be trans-
ported to the treatment plant and the volume which overflows to the river
during wet weather events. The Main Interceptor east of the Harrison/Brody
Interceptor has little capacity beyond dry weather flow.
The Main Interceptor conveys wastewater flow from the separate sewer
systems of East Lansing, Meridian Township, and Michigan State university as
well as combined sewer flows. The majority of overflows to the Red Qpffor
River are directly from the Main Interceptor or from Main Interceptor combined
sewer diversion structures.
The Main Interceptor begins at the treatment plant. The first segment is
a 54-inch diameter section which extends eastward to the point where separate
flows from the 48-inch Michigan State Interceptor discharge into it. There is
one 24-inch separate sewer collector which flows into this section as well.
Maximum capacity estimated for this segment is 40 MGD.
The 54-inch influent line to the wastewater treatment plant has an emer-
gency bypass about 1000 feet upstream of the plant which, during high flow
conditions, can direct flow to the 60-inch treatment plant effluent pipe.
The overflow manhole on the 54-inch influent sewer has an invert elevation of
2 - 4
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814.10 feet, while the 48-incii diameter overflow to the 60-inch effluent
sewer has an invert elevation of 819.98 feet. At the 60-inch effluent pipe,
the 48-inch overflow pipe has an invert elevation of 821.50 feet, while the
60-inch effluent pipe at that point has an invert elevation of 815.47 feet
according to the record drawings. The 48-inch overflow pipe is actually
negatively sloped to the 60-inch effluent pipe. This means that an overflow
would occur only if wastewater could not enter the treatment plant, sur-
charging the Main Interceptor. The 48-inch overflow pipe is also fitted with
a flap gate at the point at which it discharges to the 60-inch effluent pipe.
This bypass has not operated to date. The intent of the bypass is to protect
the plant in the event of a significant extended power failure.
Main Interceptor. 48-Inch Segment
The next segment of the Main Interceptor is a short 48-inch section from
the 54-inch sewer to the point where the Harrison/Brody Dorm Interceptor joins
it. Maximum capacity is estimated at 21.5 MGD. There are no overflows from
this segment.
Main Interceptor. 33-Inch Segment
The next segment of the Main Interceptor is a 33-inch diameter sewer
extending from the Harrison/Brody Dorm Interceptor east along the Red Cedar
River to the Charles Road Interceptor. This segment receives flow from a
second section of the Harrison drainage area through the Harrison/Kellog
Interceptor. Separate flow from 27-, 15-, 18-, 30-, 12-, and 10-inch sani-
tary sewers serving the Michigan State campus enter this segment. Capacity
of this segment is estimated to be 8.4 MGD.
There is one overflow (005) which relieves the 33-inch portion of the
Main Interceptor. An overflow at this outfall would include wastewater
originating in separate service areas.
CXttfall 005 is located on the interceptor east of Harrison Avenue near
the MSU Fieldhouse. The structure is located directly on the interceptor with
no other sewers draining to the structure at that point. The interceptor is
33-inches in diameter at the point at which the outfall structure 005 is loca-
ted. The overflow structure 005 is detailed on a drawing by Hubbell, Hartger-
ing and Roth, dated June 1927, and titled "City of East Lansing Sanitary Sewer
Interceptor" sheet 3 of 7.
The outfall structure itself consists of an underflow baffle off the side
of the 33-inch diameter interceptor for a length of 5 feet, which is the inte-
rior width of the structure. The underflow baffle extends down to the spring-
line of the 33-inch interceptor. The invert elevation of the interceptor at
the outfall 005 structure is 822.10 as per the record drawings. Thus, the
approximate elevation of the underflow baffle is about 823.48 feet. Flow
from the interceptor passes beneath the side underflow baffle into the
adjacent underflow chamber. An overflow occurs when the level in the under
2-8
-------
flow chamber reaches the overflew point. The overflow point is set at the same
elevation as the crown of the interceptor at that point, which is about 824.85
feet. Any surcharge of the interceptor at this point results in an overflow.
The overflow itself consists of three 12-inch diameter pipes fitted with flap
valves which overflow from the underflow chamber to the overflow chamber. The
overflow is then carried from the overflow chamber to the river by means of a
21-inch diameter sewer. The elevation of the overflow pipe at the river is
unknown other than a note on the record drawings that the invert is to meet
the "low water" elevation.
The IM Siphon is located on the 33-inch segment. It consists of two 16-
inch and one 8-inch pipes which convey flow beneath the Red Orinr River.
Main Interceptor. 27-Inch Segment
The next segment of the Main Interceptor is the 27-inch conduit from the
Charles Road Interceptor to just west of Bogue Road. There are several sani-
tary sewers from the Michigan State campus, ranging from 10-inch to 22-inch
which join this segment. This segment was recently relined from just west of
Bogue Road to just west of Farm Lane using the Insitu Form method. This seg-
ment is located beneath sensitive botanical areas of the campus, making main-
tenance or reconstruction difficult. Maximum hydraulic capacity is estimated
to be 5.0 mgd.
There is one active overflow associated with this segment, 007. Overflow
008 which is also located in this segment is permanently sealed with a plate
and mortar and no longer functions.
Outfall 007 is located on the MSU campus in the botanical gardens at the
junction of the 60-inch diameter Charles Road Interceptor and the 27-inch Main
Interceptor. This structure is detailed in a drawing by Hubbell, Hartgering
and Roth, dated June 1927 and titled "City of East Lansing Sanitary Sewer
Interceptor" sheet 7 of 7.
The outfall structure 007 is located at the point at which the intercep-
tor changes from a 27-inch to a 33-inch diameter. The configuration of this
structure is such that the 60-inch Charles Road Interceptor enters a chamber
at an invert elevation of 824.35 feet, as per the record drawings. The normal
outflow from this chamber is through an 18-inch diameter sluice gate at invert
elevation 824.10 feet. This sluice gate discharges into a second chamber, the
outflow from- which is through another 18-inch pipe to discharge into a third
chamber in which the flow from the Charles Road Interceptor combines with the
flow in the 27-inch interceptor. Normal outflow from the third chamber is
through the interceptor which is 33-inches in diameter. The invert elevation
of the 27-inch diameter interceptor in the third chamber is 823.6, as per the
record drawings.
Overflows can occur by two different means at this structure. If the
depth of flow in the 60-inch Charles Road Interceptor is greater than 2.05 feet
2-9
-------
at the first chamber, an overflew dam at elevation 826.4 is overcome and flow
is directed to the Red Cedar River by means of a 6'-4" by 8'-0" box section,
the outlet at the river is normally submerged and at an elevation of 820.0 feet.
If the depth of flow in the third chamber (Main Interceptor Flow) exceeds 2.75
feet (an elevation of 826.35), flow is directed out three 12-inch overflow pipes
fitted with flap gates, which discharge to an overflow chamber, which in turn
discharges to the 6'-4" by 8'-0" box section and out to the river as previously
described.
Main Interceptor. 24-Inch Segment
The final segment of the Main Interceptor is a 24-inch sewer from just west
of Bogue Road to the structure for Outfall 013. Overflow structure 013 is the
point where flow from the Willmarth CSSA enters the interceptor system. The
diversion chamber for receiving flow from CPdar Street CSSA, and Outfall 009,
are also on this segment. Separate sanitary flow from the 24-inch sanitary
collection sewer which serves the eastern portion of East Lansing and por-
tions of Meridian Township also enters the interceptor system at structure
013. Capacity is estimated to be 2.5 to 4.2 MGD.
Outfall 009, known as the Water's Edge or Cedar Street overflow, is located
just east of the point at which Qriar Street extended intersects the Red Cedar
River. The overflow structure is detailed in a drawing by Hubbell, Roth and
Clark, dated March 19, 1956, and titled "City of East Lansing, Michigan Storm
Relief Sewer Project" sheet 13 of 13.
The Outfall 009 structure consists of three distinct chambers. The east
chamber receives a 42-inch diameter sewer from the north at an invert eleva-
tion of 828.50 feet. This 42-inch diameter sewer exits the east chamber as
an overflow to the south at an elevation of 829.50 feet. The point at which
the 42-inch sewer discharges to the Red Ctedar River through a flap gate is
at invert elevation 829.00 feet. Flow from the east chamber is via a 10-inch
diameter open channel through the center of the chamber at invert elevation
827.75 feet. The east chamber also receives a 24-inch sewer from the east
which passes through the base of the east chamber, but does not actually
connect. In the same manner both the 24-inch sewer from the east and the
10-inch sewer from the east chamber pass through the base of the middle
chamber, but do not actually connect. Both of these sewers discharge into
the west chamber, with the 10-inch discharging through a sluice gate. The
center chamber receives an 84-inch sewer at an invert elevation of 830.20
feet. An 84-inch overflow sewer exits the middle chamber at 830.20 feet
(the same elevation as the incoming sewer) to discharge to the Red Cedar
River at invert elevation 830.00 feet through a flap gate.
City of East Lansing personnel commented during a May field inspection
that there has rarely been an occasion that this 84-inch flap gate opened.
Normal flow exits the center chamber by means of a 12-inch diameter open
channel through the center of the chamber at elevation 828.70 feet. This
12-inch channel discharges into the west chamber through a 12-inch sluice
gate. Flow from the west chamber discharges into the interceptor, at which
point it is 24-inches in diameter.
2-io
-------
The overflow structure for Outfall 013 from the Willmarth CSSA is located on
Grand River Avenue near the intersection of Spartan Avenue. This structure
is detailed in a drawing by Hubbell, Roth and Clark, Inc., dated May 11,
1960 and titled "Sanitary Interceptor extension to intercept the Willmarth
Drain, City of East Lansing, Ingham County, Michigan" sheet no. 2.
Flow from the separate sewer area to the east flows to the location
of the 013 structure via a 24-inch sewer. At the 013 structure, the 24-inch
sewer flows through a series of four manholes in a "U" configuration. The 013
structure is located within the "U" created by the 24-inch sewer. The struc-
ture receives flow from the north in a 54-inch sewer at invert elevation
828.53 feet. This 54-inch sewer flows into an overflow tank, which is con-
tained by a broad crested weir about 46 feet in length at elevation 831.23
feet. At the base of the "U", flow from the overflow tank passes to the 24-
inch interceptor through a 12-inch sluice gate. If the depth of flow in the
overflow chamber exceeds the 821.23 weir elevation, an overflow occurs, at
which point the overflow is directed to the south through a 54-inch sewer to
discharge to the Red Qpdar River. This outfall pipe is at an unknown eleva-
tion and is a free discharge (no flap gate).
Figure 2-3 illustrates the 100-year flood boundary adjacent to the Red
Cedar River in East Lansing. The Main Interceptor is in the flood plain for
much of its length. Manholes and diversion structures are not flood-proofed,
so inflow from high river levels is possible. Inflow through flap gates held
open by logs or other debris has also been reported.
Michigan State Interceptor
The Michigan State Interceptor runs from its connection to the Main
Interceptor south and east to the Hamilton Road Pump Station. It is a 48-inch
sewer from the Main Interceptor to Grand River Avenue and East Brookfield
Road. A 36-inch sewer runs east from this point to the Hamilton Road pump
station. This sewer was constructed with MSU funds and has a capacity of
44 cfs (28.53 MGD). The portion in Meridian Township was constructed by
the Township. The City of East Lansing participated in the construction
and had the rights to 20 cfs (13 MOD) of the capacity which were assigned
to Meridian Township. The remaining capacity is reserved for the University.
There is one siphon belonging to Meridian Township on this interceptor. There
are no known overflows.
pfaTJson/Brody Dorm Interceptor
This 36-inch interceptor conveys combined flow from the Harrison Road
CSSA, separate flow originating at the Woodingham Road Pump Station and some
separate flow which enters along its length. A major overflow point (004) was
recently reduced when additional capacity was added to the Brody Dorm Siphon.
Maximum flow this interceptor can deliver to the Main Interceptor is estimated
to be 15 mgd.
The Brody Siphon conveys flow in this interceptor under the Red
2-11
-------
i
SANITARY J SEWEFE
fa » \ t
/* Ly
-INTERCEPTORS, 5
"^ ~
CITY OF
EAST LANSING
Michigan
FLOW FROM
HAMILTON RD
PUMP STA
100 YEAR FLOOD BOUNDARY
_._ INTERCEPTOR
2-12
HGURE20
100 YEAR FLOOD BOUNDARY
-------
River to the Main Interceptor. The siphon is located west of Harrison and
south of Brody. The Brody siphon was originally constructed with dual 6-inch
barrels. It was upgraded in 1956 with the addition of a third barrel 12-
inches in diameter. The capacity of this siphon was further upgraded in 1989
with the addition of a fourth barrel 24-inches in diameter, at which time the
existing dual 6-incii barrels were plugged.
The current configuration of this siphon is detailed in three drawings by
Hubbell, Roth, and Clark, Inc. dated July 16, 1988, and titled "Brody Dorm
Siphon Addition". The current operational scenario of the Brody Siphon is
such that the dry weather flows are delivered to the 24-inch barrel with an
overflow weir to the 12-inch barrel during high flows or wet weather. If the
capacity of both the 24-inch and 12-inch barrels is exceeded, the flow over-
flows through the chamber of the plugged dual 6-inch barrels and to an over-
flow chamber through two 12-inch "duck bill" backflow preventing valves (one
of the existing 12-inch overflow pipes is bulkheaded) . These two 12-inch
overflow pipes discharge to a 36-inch pipe which then discharges to the Red
cedar River. This overflow structure configuration is present on each side
of the river. During a May 1989 field investigation, only the upstream (north
river bank) structure was capable of overflowing, while that on the downstream
end (south river bank) was bulkheaded with temporary (removable) bulkheads.
Harrison/Kellog Interceptor
This interceptor is a smaller diameter sewer which conveys flow from a
portion of the Harrison Road CSSA to the Main Interceptor. Maximum capacity
of this sewer is estimated to be 2.5 MED. Flow is conveyed beneath the river
by 10-and 6-inch siphons.
Outfall 000 is located upstream of the siphon. According to City of East
Lansing personnel, the 18-inch overflow pipe from the north structure of the
Kellog Siphon is collapsed and therefore incapable of overflowing. The siphon
and north and south river bank structures are detailed on a drawing by
Hubbell, Hartgering, and Roth dated February 1928. When it was discovered
that this overflow pipe had failed, the 18-inch outfall pipe was plugged with
concrete at the river.
Road Interceptor
The Charles Road Interceptor is a 60-inch sewer conveying flows from the
Charles Road CSSA to a diversion structure which joins the Main Interceptor.
This sewer is partly on Michigan State property, and as such may be difficult
to maintain. Available sewer mapping does not indicate if separate flows from
the campus enter this sewer. However, its location indicates that such con-
nections exist. Maximum capacity of this interceptor is estimated to be 90
M3D.
COMBINED SEWER SERVICE AREA
A large part of the older, central portion of the City of East Lansing is
2-13
-------
served by ccmbined sewers. There are four main drainage areas which collect
sanitary sewage and surface runoff in a combined sewer system. Wet weather
flow in the system typically exceeds the capacity of the Main Interceptor sys-
tem, causing overflow to the Bed CBAA-T River. As previously discussed, six
active overflows are from the interceptor system, or at the junction of the
combined system with the interceptor. The characteristics of each drainage
area are discussed below.
Harrison Road CSSA
The Harrison Road CSSA is the western-most drainage area served by com-
bined sewers. It totals 509 acres. Land use is residential and commercial.
There are two major subareas, designated by the interceptors, conveying flow
from the area. A summary of the major collectors is found in Table 2-2. The
west Harrison subarea consists of 434 acres. Flows are transported from this
subarea through the Harrison/Brody Interceptor to the Main Interceptor. The
largest collector of this subarea is a 72-inch sewer under Michigan Avenue
between Kensington Road and Harrison Avenue. A collector consisting of 60-
inch, 54-inch, 48-inch and smaller diameter sewers feeds the 72-inch collector
at Kensington Avenue. Another major branch consisting of 60-inch, 54-inch,
and smaller diameter sewers enters the 72-inch sewer through a diversion
chamber at Harrison Road and Michigan Avenue. This chamber is the diversion
point to CXrtfall 010.
Dry weather flow in the 72-inch sewer is east to west from Kensington
Avenue, and west to east from Harrison Road to a junction chamber located 358
feet west of Kensington Avenue in Michigan Avenue. Flow then proceeds from
the junction chamber southwest through a 24-inch sewer to a second manhole in
Michigan Avenue. This second manhole also receives combined flow from a 36-
inch combined sewer and separate sanitary flow from a 24-inch sewer which
originates at the Woodingham Pump station. All wastewater then flows through
the Harrison/Brody Interceptor to the Main Interceptor.
During wet weather, wastewater and runoff flows eastward in the 72-inch
interceptor from the junction chamber to the diversion structure at Michigan
and Harrison. CXitfall 010 is the major point of overflow for the Harrison
Road CSSA.
Outfall 010 is located near the intersection of Harrison Avenue and
Michigan Avenue. This structure is detailed in a drawing by Hubbell, Roth and
Clark, Inc., dated March 19, 1956, and titled "City of East Lansing, Michigan
Storm Relief Sewer Project" sheet 2 of 13.
The overflow structure at outfall 010 consists of a simple diversion
chamber at which flow from the north in a 60-inch sewer makes an approximate
90 degree bend into a 72-inch sewer. At the bend, an overflow dam is built
such that when the depth of flow in the diversion chamber exceeds the height
of the dam, an overflow occurs. The invert elevations of the 60-inch and 72-
inch sewers as they enter the diversion chamber are 826.79 feet and 826.50
2-14
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feet respectively. The elevation of the concrete dam in the diversion chamber
is 827.80 feet as per the record drawings. Overflows are directed to the Red
radar River via an 84-inch sewer which discharges to the river at an invert
elevation of 825.30 through an 84-inch diameter flap gate.
Wet weather flows in the 36-inch combined sewer tributary to the manhole
south of the junction chamber will overflow with sanitary wastewater plus flow
from the junction chamber at Outfall 004 or reverse flow to the junction
chamber and become part of the overflow at 010.
The second subarea, East Harrison, is tributary to the Harrison/Kellog
Interceptor. A 24 x 36 inch channel and smaller diameter sewers are tributary
to a diversion chamber also located near the intersection of Harrison Road and
Michigan Avenue. There are two outfall sewers and two Outfalls, Oil and 012,
for this junction chamber to the Red Cedar River. Dry weather flow is con-
veyed from this diversion structure through the Harrison/Kellog to the Main
Interceptor. There is a separate storm sewer also tributary to Outfall Oil.
There are no record drawings available for this diversion chamber. Major
collectors are summarized in Table 2-3.
Charles Street CSSA
The Charles Street CSSA is located immediately east of the Harrison Road
CSSA. It consists of a mix of residential and commercial land uses, covering
249 acres. There is one major collector, consisting of 60-inch, 54-inch, 48-
inch and smaller sewers which run north-south through the center of this ser-
vice area. Two 24-inch collectors join the 54-inch collector at Albert and
Charles Streets, and 193 feet south of that intersection, respectively. Table
2-4 summarizes the hydraulic characteristics of the collectors in this service
area.
All flow, wet or dry weather, is conveyed to the Main Interceptor through
the Charles Road Interceptor. Wet weather overflows are through the diversion
associated with Outfall 007. Overflows at that location were covered in the
interceptor discussion. There is some overlap of this service area with the
Cedar Street CSSA. Interconnections were identified in the vicinity of
Elizabeth Street and Baily Street.
street CSSA
Cpdar Street CSSA is located between the Charles and Willmarth service
areas. It covers 191 acres. Land use is residential and open space asso-
ciated with two schools on the northern edge of the service area. There are
two subareas, with interconnections, which have been designated East and West
Cedar Street, respectively. The largest collectors are associated with the
East Cedar Street subarea. These include a 78-inch, 72-inch, 54-inch and
smaller sewers. A 36-inch and smaller sewers serve the West Cedar Street sub-
area. In addition to the cross connections with the Charles Street CSSA,
there is an area of cross connections with the Willmarth CSSA. These are
located in the vicinity of Gunson Street from Albert to Collingwood Drive.
2-16
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Both east and west subareas are tributary to the Main Interceptor at an
interconnected series of structures associated with CXitfall 009. This struc-
ture was discussed in the interceptor section. Hydraulic capacities are
listed on Tables 2-5 and 2-6.
Willmartfa CSSA
The Willjmarth CSSA is the eastern-most combined sewer service area in the
City of East Lansing. The Willmarth area covers 697 acres. land use in the
area is residential. There is one major collector which bisects the service
area. It consists of 54-inch, 48-inch, and smaller sewers. Table 2-7 sum-
marizes the hydraulic characteristics of the Willmarth collector system.
All flow enters a diversion structure located on Grand River Avenue about 250
feet southeast of its intersection with Spartan Avenue. This structure is
associated with Cutfall 013.
SEPARATE SEWER SERVICE AREA
East Lansing conveys and treats wastewater frcm areas served by separate
sewers. These areas surround the combined sewer service areas on three sides
- north, east, and south. The northwest portion of East Lansing is tributary
to the Wocdingham pumping station. Flows frcm the northern part of Meridian
Township are monitored at Towar Park and subsequently pumped through Wood-
ingham Pump Station. Flow from the pump station is by gravity through a 36-
inch, then a 24-inch sewer to a junction chamber in Michigan Avenue east of
Kensington Road which discharges to the Harrison/Brody Interceptor.
The area of East Lansing east of the Willmarth CSSA has separate storm
and sanitary sewers. Flow from this area and from an adjacent portion of
Meridian Township is conveyed through a 24-inch separate sanitary collector
to the Main Interceptor at the diversion structure to overflow point No. 013.
The Michigan State campus is served by separate sewers. This sanitary
flow is discharged to either the 48 inch diameter interceptor through the
southern part of the campus, or to the Main Interceptor. Flows conveyed
through the Main Interceptor system enter directly at manholes along the line,
through a 27-inch and 30-inch sanitary collectors in the campus area, and to
the Charles Road 60-inch interceptor.
Meridian Township also discharges wastewater to the 48-inch MSU Inter-
ceptor through a 40- and 36-inch section owned by Meridian Township. Most of
the flow passes through the Hamilton Road Pump Station. This facility is
owned and operated by Meridian Township. Flow is monitored at this point
through pumping records. Smaller volumes of wastewater also enter the MSU
Interceptor System frccn Meridian Township.
A small area west of the MSU campus, and east of I-496/Highway 127 is
served by separate sewers. This wastewater is conveyed through a 24-inch
collector to the Main Interceptor about 1500 feet east of the treatment plant.
2-19
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Flow is estimated for separate sewer areas in Meridian Township and for
the MSU campus because service is provided on a contract basis. There are
four direct measurements of wastewater flow. A flow meter at Towar Park
measures flow from northern Meridian Township. Flow is also measured through
pumping records at the Woodingham Pump Station. This measurement includes the
flow from Towar Park. The Hamilton Road Pumping Station and the East End Lift
Station measure flow with a magnetic meter. All other contract flows, includ-
ing those from MSU are estimated based on water usage.
Table 2-8 summarizes recent separate sewer service area flows, and indi-
cates the receiving interceptor system for each flow. Approximately 3.0 mgd
of average flow conveyed by the Main Interceptor originates in separate sewer
areas. A little over 4 MGD is conveyed through the 48-inch MSU Interceptor to
the 54-inch portion of the Main Interceptor.
A study by Hubbell, Roth, and Clark for the City of East Lansing examined
wet and dry weather flows in the area tributary to the Woodingham Pump Station
to determine design criteria for an expanded pump station. Dry weather flow
was estimated to be about 1 MGD. Peak wet weather flows to the pump station
were estimated to be about 10.3 MGD. Inflow was judged to be uniformly dis-
tributed in the separate sewer area of East Lansing and Meridian Township.
This conclusion is supported by flow data recorded in October and November,
1988. Rainfall over a one-week period totaling about 3 inches caused an
increase of flow to the station from 1.2 MGD to 3.34 MGD. Rainfall of 0.3
inches resulted in an increase in one day from 1.36 to 2.34 MGD.
Similar records for other separate sewer areas are not readily available.
However, it is apparent that similar increases in wet weather flow in other
separated sewer areas have a direct effect on overflow occurrence and volume.
Increased flow from the Vfoodingham Pump Station may cause an overflow at Out-
fall 004. Similarly, increased flow from the separate sewer area tributary to
the 2 4-inch sanitary collector in Timber lane Road will contribute to over-
flows at outfalls 007 and 009.
Sewers on the MSU campus were separated in about 1960. Since there are
no wastewater flow records from the University, the presence or absence of
increased wet weather flows from this source cannot be projected. Because
the University covers a large portion of the total East Lansing service area,
increased wet weather flows from this source, if they exist, would have a
significant impact on overall interceptor capacity and overflow volume and
occurrence.
2-23
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TABLE 2-8
Separate Sewer Area Flows
Average
Source 7/1/86-6/30/87
MGD
Michigan 1.56
State
University1 1.18
2.743
-State Police 0.12
Meridian
Township
-Hamilton 2 . 65
Road Lift
Station
-Other East 0.49
Meridian
Township
Service
-Towar Park4 0.42
Average Receiving Estimating
7/1/87-6/30/88 Interceotor Basis
MGD
1.62 57%-MSU2
Interceptor
1.22 43% Main
Interceptor
2.843
0.14 Main
Interceptor
2.78 MSU
Interceptor
0.48 24-inch collec-
tion Timber-
lane, to the
Main Interceptor
0.34 Brody/Harrison
& Main Inter-
Water
Usage
Water
Usage
Magnetic
Meter
Magnetic
Meter
Water
Records
Ultrasonic
Meter
-Woodingham
Pump Station
1.37-
ceptor
Brody/Harrison
& Main Inter-
ceptor
1. Includes MSU Credit Union, State Control Ld.
2. Campus flow divided based on estimated tributary areas.
3. Total MSU flow.
4. Included in Woodingham Pump Station Flow.
5. August 1988 through April 1989 - for relative comparison only.
2 - 24
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WASTEWATER TREATMF77T PIANT
A schematic diagram of the existing treatment facilities is shewn in
Figure 2-4. The overall plant design average day flow is 15.0 MGD, with a
peak flow of 40 MGD. Ihe design criteria also provide a rating of 18.75 MGD
Average Day of the Maximum Month, and 30 MGD Maximum Day. Major components of
the plant are described below.
Influent Sewer
Flow into the plant is via a 54-inch influent sewer, which has an
estimated capacity of 42 MGD and an invert elevation of 813.30 feet.
Screening
The flow then passes through the communitors and bar screens before
discharging into a wetwell. The two ccmmunitors each have a hydraulic
capacity of 19 MGD with the bar screens acting as a communitor bypass.
Raw Sewage Pumps
Flow from the wet well is then lifted to the grit chambers by means of
six lift pumps (4 constant speed and 2 variable speed) with a total capacity
of 48 MGD (8 MGD maximum each) .
Grit Chamber
The grit chambers each have a total volume of 94,000 gallons. The
aeration capacity at the grit tanks consists of two blowers at 280 scfm each.
The grit removal system also includes two grit washers at 200 gpm each and two
scum pumps at 85 gpm each.
Equalization Basin
The Equalization basin has a volume of 5 million gallons and is aerated.
This volume allows for a detention time of 7.6 hours at design flow and 3.0
hours at peak flow. The aeration capacity consists of three blowers at 7,000
scfm each (two in service one standby) .
Flows from the equalization basin are pumped to the two plants (north and
south) by means of three 20 MGD pumps for a total capacity of 60 MGD. While
the original design had the design flow of 18.75 MGD split 6 MGD/12.75 MGD for
flows to the south and north plants, respectively, the current operational
procedure is to route 3 to 4 MGD to the south plant with the balance of the
flow treated by the north plant.
Settlin Tanks
The north plant has six primary settling units at 16 feet wide x 117 feet
2-25
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LJ
3
1
C/l
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tc.
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- 26
-------
long x 12 feet deep each for a total volume of 1,008,000 gallons and a deten-
tion time of 1.9 hours at 12.75 MGD. The south plant has four primary set-
tling units of the &w dimensions as those for the north plant for a total
volume of 672,000 gallons and a detention time of 2.7 hours at 6 VIED. The
design flow for the north primary tanks is 12.75 MGD while that for the south
primary tanks is 6 MGD.
Aeration Tanks
The north plant consists of ten aeration basins 24 feet wide x 180 feet
long x 15 feet 3 inches deep for a detention time of 9.3 hours at 12.75 MGD
design flow; 6.2 hours detention time at 12.75 MGD and 50 percent sludge
return. Five tanks are out of service. Each aeration basin contains 494,000
gallons.
The south plant has seven aeration basins 18 feet 6 inches wide x 125
feet long x 14 feet 3 inches deep for a detention time of 6.92 hours at 6 mgd
design flow; 4.61 hours detention time at 6 MGD and 50 percent sludge return.
Two tanks are kept out of service. Each of these tanks is 247,000 gallons.
Secondary Settling Tanks
The north plant consists of three secondary settling units 90 feet in
diameter with a 12 foot side water depth, for a total volume of 1,712,450
gallons and a detention time of 3.22 hours at 12.75 M3D.
The south plant consists of four secondary settling units 57 feet in
diameter with a 12 foot side water depth, for a total volume of 920,000
gallons and a detention time of 3.67 hours at 6 MGD.
Tertiary Treatment
The tertiary treatment plant consists of four two-cell mixed media
filters with each cell measuring 14 feet x 28 feet for a total filter area of
3,136 square feet. At a flow rate of 18.75 MGD, the corresponding filter rate
would be 4.15 gallons per minute per square foot of filter area. There are
two backwash pumps each rated at 7050 gpro.
Flows
A summary of an analysis of flow records at the treatment plant is
provided in Table 2-9. As shown, the average dry weather flow for the period
March through November for 1987 and 1988 was 10.27 MGD. The period December
through February was not considered in order to eliminate inaccuracies due to
freeze/thaw conditions. The average flow for only the period June through
August for the same years was 9.09 MGD. The difference between the average
for this period and that for March through November (1.18 MGD) is represent-
ative of the flow contribution of the transient MSU student population.
The diurnal flows at the plant as observed at the grit chamber (upstream
of the equalization basin) result in a peaking factor from the average flow of
about 2.0, while the low flow factor is about 0.20.
2 - 27
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Wet weather flows for the period March through November of 1987 and 1988
are also shown in Table 2-9, distributed by rainfall event volume. As shown,
the volume of rain is directly proportional to increased plant flows.
TABLE 2-9
WWTP FLOWS (MD)
PER 1987 AND 1988
_Avq._ _Min._ _Max._
Dry Weather Flow: (Mar - Nov) 10.27 6.60 12.90
(Jun - Aug) 9.09 6.60 21.30
Wet Weather Flow: (Mar - Nov) Ava._ _Min._ _Max.
<0.20" Rain 11.46 1.38 18.50
0.20" - 0.50" Rain 11.94 8.06 15.00
0.50" - 1.00" Rain 13.66 9.90 18.50
>1.00" Rain 15.55 12.40 21.10
NOTE: Values are based on daily total flows from the NPDES reporting form
for the East Lansing Treatment Plant. Peak instantaneous observed
flow rates at the plant would exceed these values.
2-28
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Chapter 3
OCKTODLS
The preparation of an operational plan to control CSOs includes a review
of administrative controls. This chapter describes administrative controls
and includes recommendations for modifying them to be consistent with the
objectives of the operational plan.
The City of East Lansing is subject to the rules promulgated in the
Michigan Administrative Code, Department of Natural Resources, Water Commis-
sion General Rules Part 21, which establishes administrative procedures for
issuance of National Pollution Discharge Elimination System permits by the
State of Michigan.
East Lansing recently renewed Permit MI0022853 which establishes effluent
limits for discharge from the treatment plant outfall (001) to the Red Cedar
River. The City is also permitted to discharge up to 4.0 M3D to Michigan
State University, (NPDES) Institute of Water Research through NPDES Permit
No. MI002321, CXrtfall 003. A copy of the permit is included in Appendix 3A*.
In addition to the effluent limitations, the City also has requirements for
controlling and monitoring the residual solids management program, containment
of materials required by Section 5 of the Michigan Water Resources Commission
Rules and reporting of any bypassing of overflows from CSO or accidental
losses for the system.
The City is complying with the requirement for reporting bypassing events
through a recently established monitoring program. This program includes a
daily inspection of overflow structures for bypassing of the collection system
by members of the sewer maintenance department. Overflow events are visually
monitored during rainfall events. Staff members are on call to conduct this
monitoring. A copy of the form used for this monitoring program is found in
Appendix 3B*.
EXISTING CONTROLS
City Sewer Use Ordinance
The City of East Lansing has several methods of controlling sewer usage.
These include the sewer use ordinance and service contracts which are
described in this section.
The sewer use ordinance defines procedures for making connections to the
City system, gives construction requirements, and limits materials which may
be discharged. A copy of the sewer ordinance is reproduced in Appendix 3C*.
Major elements of the ordinance include:
3-1
*NOTE: Appendices 3A, 3B and 3C are not included as part of this exanple
document.
-------
o Connection to the city system can be made as long as sewer service is
within 100 feet of the property line. Each building is required to have
a separate and independent lateral. An old lateral may be reused when a
building is replaced by a new building. The plumbing inspector must
examine and test the lateral to dett~mine that it meets chapter require-
ments.
o Prohibited discharges to the sewer system are listed in the sewer ordinance
found in Appendix 3C*. This list is modified and supplemented in the pre-
treatroent ordinance.
o Grease, oil, and sand interceptors (traps) may be required on the recommen-
dation of the City Engineer. Accessibility of the traps for inspection and
maintenance is required.
o Preliminary treatment by the discharger may be required if 8005 levels of
the waste exceed 300 ppm (mg/1) or if suspended solids exceed 350 ppm.
Quantity of discharge may be subject to control if it exceeds 2 percent of
the average daily flow.
o Industrial waste dischargers may be required to install monitoring man-
holes.
o There is a prohibition of discharge to storm sewers other than "storm
water or uncontaminated industrial waste."
o A rate schedule for water and sewer service is established.
Chapter 24A of the sewer use ordinance adopted June 4, 1985, provides
detailed industrial pretreatment requirements. It was promulgated to bring
the city into compliance with Federal Regulations (40 CFR Part 403) and State
of Michigan Laws (Act 245 of Michigan Public Act 1929 as amended, and Section
1 and 11 of Michigan Act 98 of Public Acts of 1913 as amended). Limits for
some parameters such as the temperature criteria are modified from the ori-
ginal sewer ordinance. Wastewater discharge permits are required of all
significant industrial discharges (as defined in the ordinance). other
industrial or commercial users may be required by the city to obtain a permit
as well. Requirements of the permit application are found in Appendix 3C*.
Currently there are no sewer users in the City of East Lansing which are
administered under the pretreatment ordinance.
Service Contracts
The City of East Lansing provides wastewater conveyance and treatment for
Michigan State University and Meridian Township on a contractual basis. Each
contract is discussed below. Copies of the MSU and Meridian Township
contracts are included in Appendices 3D* and 3E* respectively.
3-2
*NOTE: Appendices 3C, 3D and 3E are not included as part of this example
document.
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Michigan State Contract
Agreements for wastewater conveyance and treatment have existed between the
City of East lansing and Michigan State University since 1927. University
ownership of lands where major interceptors and treatment facilities are best
located, coupled with the need for treatment of wastewater originating at the
University have made these agreements necessary. Land for the original East
Lansing treatment plant, located west of Harrison Road and south of the Red
Cedar River, and the right of way for the Main Interceptor east of that point
were leased for 99 years from the University in the 1927 agreement. Cost
apportionment was begun in the 1927 agreement.
In 1963 an updated agreement was developed between the University and the
City of East lansing. The City needed to lease additional land and obtain
funding to build what is the south portion of the existing treatment plant,
and the 54-inch portion of the Main Interceptor. In addition, the City
obtained rights by sharing construction costs for 20 cfs of the 44 cfs
capacity of the 48-inch MSU Interceptor. This 20 cfs capacity right was in
turn conveyed to Meridian Township. The old treatment plant site reverted to
the University.
The 1963 agreement granted Michigan State a minimum of 3 MGD average flow
capacity in the treatment plant. Cost sharing was further refined. Opera-
tional costs attributable to the University were based on water usage. A
general statement that sewage detrimental to the disposal system or public
health or safety is included. The location of future sewers or drain lines
to be located on University property was made subject to University approval.
Trees or buildings may not be damaged without written consent.
The 1963 agreement was updated in 1972, when the treatment plant was
expanded. The University's capacity rights were extended to 6 MGD maximum
flow. This agreement also stated that Meridian Township would have 5 MGD
capacity rights. For purposes of the agreement the size of the expanded
treatment plant was set at 15 MGD, leaving 4 MGD for the City of East Lansing.
Any party could use more than its share if capacity existed, but such use did
not create a permanent entitlement.
An addendum to the 1972 agreement was approved in 1984. A surplus in bond
repayment funds generated a sufficient surplus to repay the bonds with no
further collection of payments from the University.
A supplement to the 1963 agreement was signed in May, 1988. It incorpo-
rated the pretreatment ordinance (Chapter 24A), including numerical limits for
several parameters. The University agreed to assume responsibility for moni-
toring and control of its effluent. A procedure for determining University
pollution contributions to sewers with mixed flows is described. The City can
require inspections and monitoring to determine the source of pollutants. The
University is to notify the City of unusual discharges.
3-3
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Meridiem Township
The initial contract for service with Meridian Township was signed in
January of 1961. East Lansing agreed to provide conveyance and treatment of
wastewater; Meridian Township agreed to pay their proportionate share of the
costs. Capacity rights associated with any of Meridian Township ultimately
annexed into the City could either be retained by the township or surrendered
to the City, at the discretion of the Township. The township is responsible
for reading and maintaining all meters.
A supplement to the agreement was finalized in 1985. The 5 M3D maximum
capacity in the treatment plant was continued. A request for service from
Alaidon Township, south of Meridian Township, to be administered through
Meridian Township could not be addressed using the 1961 agreement. The 1985
supplement allowed the service to be provided upon agreement by both parties,
and adoption of an appropriate sewer ordinance by Alaidon Township. Meridian
Township was required to adopt a pretreatment ordinance equivalent to that of
East Lansing. One industry, Renn Plastics, located in Meridian Township, is
subject to pretreatment requirements of the service contract. Maximum capacity
rights through the Wcodingham Pump Station and the sewer to the diversion
structure in Michigan Avenue were set at 3.6 cfs. The City's stated intent was
to physically restrict flows to this maximum level. This device has been
installed.
RECOMMENDATIONS
Administrative Changes
Modifications to existing contracts and exercising greater control over
contract areas will enhance East Lansing's ability to reduce overflows. The
following changes are recommended:
1. Amend the sewer ordinance to prohibit roof drain discharges to the
combined sewer system;
2. Enforce residential inflow disconnections (e.g., sump pumps);
3. Require separate building laterals from storm and sanitary sewers
when reconstruction occurs in the combined sewer service area;
4. Contract directly with townships that request service;
5. Monitor University flows;
6. Obtain easements from the University for maintenance;
7. Establish a sewer utility to uniformly administer sewer ordinance
requirements; and,
8. Acquire the 48-inch MSU Interceptor to function as a relief sewer.
The City of East Lansing generally has the ability to regulate discharges
into the sewer system within its own boundaries. There is less control over
contract service areas. The City Sewer Ordinance (Chapter 24 Section 2.91)
prohibits introduction of clear water into the sanitary sewer system. There
are ways this ordinance could be strengthened.
3-4
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The sewer ordinance should be amended to prohibit roof drain discharges to
the combined systems, with exceptions granted on a case by case basis. Consid-
eration should be given to prohibiting sump pump discharges to the combined
system as well.
The ordinance currently allows roof drain and sump pump connections to the
combined system. Residential areas of East Lansing generally have sufficient
size lots to reduce this source of inflow by discharging roof runoff. Some of
this flow may reach street drains, but the time of concentration is increased.
Greater flexibility for operation of the collection system would be gained.
For some of the commercial areas, disconnection may be impractical. Consi-
deration could also be given to disconnecting sump pumps from the combined
sewers. An estimate of wet weather flow contribution of the sump pumps should
be made, and a cost-effectiveness analysis made of a disconnection program
before proceeding. For many individual properties in the CSSA, discon-
nection of sump pumps may be impractical.
Enforcement powers are available to the city under Section 2.94 of the Sewer
Ordinance. This power should be utilized to keep inflow sources disconnected.
City officials have stated that residences in the separate area of East Lansing
have been inspected, with disconnections required. Some reconnections are sus-
pected.
Separate building laterals for sanitary waste and clear water discharges
should be required when redevelopment occurs in the combined sewer service
area. Redevelopment is most likely to occur in the commercial area along Grand
River Avenue. This is also the most impervious area of the city, generating
the largest volumes and greatest intensities of runoff. If sewer separation
is pursued in the future, this area is closest to the river, and perhaps more
easily separated. Building separation would enhance the effectiveness of
future separation projects.
East Lansing should contract directly with other townships, such as Alaidon
Township, when they request service. The contract should include all sewer
ordinance provisions applicable to East Lansing. Conveyance costs to the East
Lansing system would be by separate contract with, in the case of Alaidon Town-
ship, Meridian Township.
The current institutional arrangement with both the University and Meridian
Township is that any restrictions or requirements of East Lansing are negoti-
ated as amendments to a service contract. Future growth, and subsequent
demand for sewer service, is largely occurring in townships east of East
Lansing. The control of connections is through a second, and in the case of
Alaidon Township, a third party. The current contract with Meridian Township
sets a maximum allowable flow at one connection point, Towar Park. With this
exception, there are no wet weather flow restrictions placed on these commu-
nities. East Lansing has little control over inflow from this contract area.
3-5
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The following options would provide better control of contract areas for
East Lansing:
o Require in the service contract that Meridian Township include clear
water prohibitions equivalent to those of East Lansing;
o Reguire the submittal of inspection records, and disconnection enforcement
actions to the City of East Lansing;
o Require City of East Lansing review of new development plans for com-
pliance with sewer service requirements;
o Require the results of sewer line testing for tightness before allowing
connection to the system;
o Develop a cost surcharge for flows which exceed an agreed value. This
charge would be for excess inflow or infiltration. The City should develop
a typical wastewater generation per capita rate. Allowance for acceptable
infiltration should be made. For example, Wisconsin allows a maximum
infiltration rate of 200 gallons per inch diameter of pipe per mile per day
for new sewer construction. Flows in excess of the calculated value would
be subject to a surcharge; and,
o Require wastewater, rather than water meter monitoring for those areas in
Meridian Township currently measured using the water meters.
Major University sewer lines should be monitored for both wet and dry wea-
ther flows. This data would establish the relationship between water usage
and wastewater flow. It would also indicate if clear water, especially
inflow, is a significant factor in wastewater flows from the University. By
the 1988 contract, the City can require monitoring by the University.
MSU is a major source of wastewater to the East Lansing system. Critical
facilities for conveyance and treatment are located on University-owned
property. Service and cost allocation is by contract, as previously dis-
cussed. Michigan State separated campus sewers around 1960.. All new con-
struction involves separate sewers. Based on discussions with city officials,
documentation of the effectiveness of the separation program is not readily
available. Water usage is assumed to equal wastewater contribution. This
assumption should be verified with monitoring data.
Formal easements with sufficient width for maintenance and repair purposes
should be developed with the University. These easements should cover the
Main Interceptor and the Charles Street Interceptor. Sufficient areas should
be identified for maintenance of diversion structures. These easements should
give the City the right to make repairs and modifications to these facilities,
with the understanding that site restoration would be required. The City is
limited in its ability to modify, repair, or construct additional facilities
on campus property adjacent to the Main Interceptor. The City has a lease
which allows it to operate the sewer. The Main Interceptor sewer passes
through sensitive botanical areas. The University must currently approve any
actions on its property. Lack of approval would limit the ability of the City
to make needed repairs or modifications.
3-6
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Pretreatment Controls
East Lansing should develop a pilot monitoring program for commercial
establishments which are potential sources of oil and grease to the system.
A baseline monitoring report to determine compliance with the 100 ppm oil and
grease limit, coupled with random sampling by the City would ensure
compliance.
Oil and grease, and fats which occasionally enter the collection system
from restaurants have created problems in the past. This material may collect
in sewers, reducing capacity/ or at diversion structures, overflowing to the
river in wet weather. The current program of monitoring and enforcement of
the pretreatment ordinance generally follows an actual blockage of a sewer
line with grease. Floating grease has been observed at overflow diversion
chamber 007. The City's policy is to remove blockages due to oil and grease
or fat discharges once from a sewer. The discharger is billed for any
subsequent service.
East Lansing has a comprehensive pretreatment program, in compliance with
state and federal requirements. The pretreatment ordinance has been incorpo-
rated into the Michigan State and Meridian Township contracts. There is one
industry in Meridian Township which currently is subject to the pretreatment
provisions of the service contract. Monitoring may be required of the Univer-
sity if it is a suspected source of a regulated pollutant. No monitoring has
been required to date.
Lonq-Term Administrative Recommendations
There are two long-term administrative recommendations: establish a sewer
utility and acquire the 48-inch MSU Interceptor.
City officials indicated that discussions had been held regarding
establishment of a sewer utility. It would be advantageous to establish a
sewer utility to uniformly administer requirements. A sewer utility would
have more direct control over the proper construction of new sewer
connections.
It would also be in the best interest of East Lansing to acquire the 48-
inch MSU Interceptor. It appears this sewer can function as an effective
relief sewer without limiting use by MSU or Meridian Township. This would
enable East Lansing to operate the major components of the entire collection
system to most effectively reduce overflows.
It is recognized that implementation of these items would require signifi-
cant negotiations to preserve rights of each party. All parties should recog-
nize that the objective of forming a new utility with ownership of the MSU
Interceptor would be for the purpose of efficiently operating the collection
and treatment system to minimize pollutant discharge to the Red Cedar River.
3-7
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Oiapter 4
MAINHNANCE PROGRAM
The East Lansing Department of Public Works has a well organized staff
and a cxanprehensive program for sewer maintenance. The sewer maintenance
program was reviewed as part of the overall operational plan. This chapter
provides a detailed written description of the program and includes recom-
mendations for upgrading the system.
Personnel
The Department of Public Works has a Superintendent of Sewers. He has
two crews of ten persons each who perform routine and special maintenance
tasks. Each crew operates under the direction of a crew chief.
Schedule
The city has been subdivided into nine regular maintenance areas. These
nine areas are further subdivided into two or three areas designated A, B,
and C for catch basin cleaning. Maps of the areas are found in Appendix 4A*.
The areas are inspected on a rotating basis on Mondays and Tuesdays. Problem
areas are maintained or repaired on Wednesday, Thursday, and Friday. Regular
maintenance tasks include sewer flushing, catch basin cleaning, siphon and
overflow monitoring, sewer repair, and emergency response.
Sewer Flushing
The City of East Lansing owns two sewer flushing machines. One is an
FMC. The second is an Aquatech SJ-15. The latter holds 1500 gallons, has
1500 to 2000 psi pressure, and a 30 degree nozzle. It can flush 500 feet per
run. The city also has a bucket machine. The bucket machine is used only if
flushing will not work. Experience of the maintenance department has been
that bucketing may cause some line damage.
Crews are assigned to inspect the nine sewer areas on a rotating basis.
Each inspection area has sewer lines highlighted on an assignment map which
are to be flushed on a routine basis. The crews record the location and
length of lines which have been flushed. This information is entered into
the maintenance management system on the computer. Area flushing is done on
Monday and Friday. During flushing, the manhole condition is recorded, or
any other pertinent information on the system.
Certain areas are particularly subject to sedimentation problems. Lists
have been established called the Wednesday List and the Friday List. Loca-
tions on the Wednesday List are flushed weekly. Locations on the Friday
List are divided into four groups. These are flushed once per month. The
Wednesday and Friday Lists are included in Appendix 4B*.
4-1
*NOTE: Appendices 4A and 4B are not included as part of this example document.
-------
Siphon Inspection
Siphons are critical points in the collection system which are subject to
sedimentation. The IM siphon on the Main Interceptor is inspected every Monday,
Wednesday, and Friday. The chamber is cleaned with high pressure. The Kellog
siphon is inspected once per month. The Brody Dorm siphon has not caused prob-
lems since it was replaced.
Overflow Inspection
It is the responsibility of the maintenance supervisors to inspect each
overflow point and record if an overflow is occurring. This inspection is also
conducted if it is raining, and flow to the treatment plant has reached 13.5 MGD.
Crew supervisors are on call to make these wet weather inspections. Any overflow
event is reported to Michigan ENR by telephone within 24 hours.
Catch Basin Cleaning
East Lansing began a program of catch basin cleaning recently using a Vac-
All. It is conducted on the Monday - Tuesday schedule as time permits. The nine
flushing areas are further subdivided into A, B, and in some cases, C areas for
tracking the work. Crews can clean about 15 basins per day. An inspection of
catch basin structures is conducted and recorded. Catch basins needing repair
are added to a repair list.
Sever Repairs
Problems identified during the sewer flushing, catch basin cleaning, through
citizen complaints, or other inspection are scheduled for Wednesday, Thursday,
and Friday. The city has been systematically televising sewers, especially if
a problem is suspected. The city owns televising equipment, and is upgrading it
to include computer logging. Misaligned tiles and roots are typical problems
subject to repair. There are a number of older brick manholes which require
occasional repair or replacement. Repair needs are categorized as urgent (Red),
moderate (Blue), or minor (Green).
Citizen complaints of back up are logged and examined. A review of com-
plaints indicates that less than 20 percent of them are caused by a problem with
the city sewers.
Street Sweeping
The City of East Lansing has a street sweeping program to reduce street
litter. It also serves to reduce the pollutant washoff from the streets. The
street sweeping program is conducted five days per week form April through
November. Commercial areas are swept two times per week, residential areas
once per month.
4-2
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Record Keeping
The Sewer Maintenance Department vises a Maintenance Management Informa-
tion System. The program is called "Sidekick" and is used on an IBM compat-
ible system. The program allows data to be entered and edited. The program
is currently used for data storage, and problem call documentation. The fol
lowing repair needs or activities are tracked:
1. Manhole Repair Requirements
o Major repairs
o Bottom cleaning required
o Casting to be centered
o Manholes needing to be low- =d or raised
o Brick or block under casti. ^ need replacement
o Flow lines to be constructed
2. T.irvag to be Televised
3. Sewer Repairs Required
o Urgent
o Major
o Minor
4. Root Problems by Location
5. Sewer Complaints
Work/crew activities are recorded on paper. A monthly summary of Maintenance
Department work is recorded on forms found in Appendix 4C*.
Sewer Blockage
A running summary of sewer comple'nts is kept. The most frequent com-
plaint registered is a sewer back-up problem. Problems associated with the city
sewers are found on the smaller diameter local collectors which are generally
six or eight inches in diameter. Complaints tend to be concentrated in the
Harrison and Charles CSSA, possibly because sewers are older in those areas.
The occurrence of sewer back-ups due to rainfall is limited. The following
locations have had two or more wet weather complaints and the problem was
attributed to rainfall:
o Center and Roxborough;
o Grove between Beech and Elizabeth;
o Sunrise Court and Division;
o Beech and Collingwood; and,
o Kedzie between Beech and Snyder.
4-3
*NOTE: Appendix 4C is not included as part of this example document.
-------
RECOMMENDATIONS
Ccranunication of field conditions to supervisors is one of the keys to a
successful maintenance program. City officials report an improving situation
in this regard.
Computer tracking of problems could be improved by entering additional
information concerning follow-ups to repair needs. Creation of a separate
file showing completed work versus needed repairs would be helpful. Current-
ly, the listings do not explain follow-up activities or date completed.
Since the City is divided into segments for the flushing and catch basin
cleaning, it would be useful to categorize all repair work, complaints, tele-
vising needs by these areas. This will allow efficiencies by sending crews
out to one area with several items to examine.
A greater advantage would be the ability to observe trends in repair
needs by area. For instance, if an area was indicated to have collapsed
tiles, manhole repair needs, and catch basin repair needs, a large scale
repair and rehabilitation project might be more effective than individual
repairs.
The daily information brought back from the field is currently kept on
paper copies. Consideration should be given to entering critical information
into the Maintenance Management Information System on a daily basis. The
information could then be summarized by a computer program by locations or
types of problems. For instance, observed conditions reported from the
Wednesday or Friday flushing lists, when looked at over time, should indicate
trends which require further investigation.
There is currently no record keeping on operability of flap gates for
overflows. With the recording of overflow activity, gate condition, such as
being jammed open, and any river inflow should be recorded. Problems with a
diversion structure would currently be recorded as a manhole problem. We
recommend a separate tracking of diversion structure conditions. This should
be on at least a monthly basis. As an example, two slide gates were observed
in the diversion structure for 009, but they are not believed to be operable.
Control diversion structures will be increasingly important as the system is
operated to reduce overflow.
4-4
-------
Chapter 5
CCNTR3L STRMBGY
The objective of a Combined Sewer Operational Plan is to examine
existing facilities to determine if alternate operation schemes could reduce
overflows and the resultant pollutant loadings. The proposed control stra-
tegy for combined sewer overflow at East Lansing provides a reduction in the
volume and frequency of overflow using existing facilities. long-term solu-
tions to gain greater control of overflows are also described. The control
strategy can be incrementally implemented with overflow reduction at each
step. This chapter describes the steps to be taken in order to minimize
overflows.
CONTROL
The control methodologies considered for reducing combined sewer over-
flow in East lansing are described in this section. Terminology used to
describe control measures is defined in Table 5-1.
* Storage in the Existing System. large diameter collectors in the com-
bined sewer service area have the potential for temporary storage of
smaller events or a portion of large events. This control method will
be evaluated for each of the four combined sewer service areas. Control
structures must have the ability to release flow from storage in response
to additional incoming flow to prevent backups upstream into the smaller
diameter collectors, which could potentially cause basement backups. Con-
trol structures also need to be designed to prevent sedimentation. Suffi-
cient velocity should be maintained under selected flow conditions to
permit sediment to be conveyed to the interceptor system.
* Flow Reduction. Reduction of inflow sources will reduce the intensity
of wet weather runoff. Disconnection of roof drains so that the dis-
charge to lawns will cause some of the runoff to infiltrate to ground-
water. For intense rainfall events, the time of concentration will be
slowed because of overland travel.
As previously discussed, roof drains should be disconnected in all
residential areas, separate or combined. Disconnection in commercial
areas will likely be ineffective because of the lack of pervious areas
to absorb or retard flow. Similarly, sump pump disconnection should be
required for the separate service area, and considered for the combined
areas as discussed in Chapter 3.
The rate of inflow from street drains in the combined area can be reduced
by restricting flow at the inlet. Reducing the rate of inflow would not
reduce the overall volume entering the system, and would have to be eval-
uated relative to increased street flooding. With the catch basin clean-
ing program and associated rebuilding of catch basins requiring repair,
reduction of inlet capacity should be considered for test locations.
Flow reduction is an overall strategy rather than basin specific.
5-1
-------
JStELE 5-1
LUP1NIT1CN OF TEEWS
1. In-line Storage - Storage used which consists of the volume available in
the pipe beyond the volume being occupied by the wastewater flow.
2. Off-line Storage - Storage located adjacent to a sewer which is used to
store flows which exceed the conveyance capacity of the sewer, or the
treatment capacity of the plant. Stored wastewater is punped back into
the system when capacity is available.
3. Retention Basin - A facility to store stonnwater runoff for late release
at a controlled rate.
4. Attenuation - This term refers to an action which reduces the magnitude
of a flow rate. Attenuation does not reduce the volume, but spreads the
flow of a particular volume over a greater period of time.
5. Diversion - Routing of wastewater flow from one sewer to another.
6. Flow Reduction - A measure which removes a source of clearwater from the
collection system.
5 - 2
-------
* Surface Retention. Runoff retention in engineered basins or on other large
areas requires land with upstream flow which can be routed to a site, retained
and slowly released. The combined sewer service areas of East Lansing have
few opportunities for runoff storage. Reviewing aerial photographs, the
combined area is considered fully developed. Development is more intense in
the older, downstream portion of each service area, versus the upstream areas.
Open space is limited. There is some open land, about 10 acres total,
associated with East Lansing High School and St. Thomas Aquinas High School at
the north edge of the O?dar Street CSSA and a smaller area (3.5 acres) east of
J. Hannah Middle School. The two high school properties are at the watershed
divide with portions of runoff routed north to separate storm sewers.
Retention would not be practical here; however, routing of runoff from the
high school parking lot to the separate area would be desirable.
The middle school open area is also near a watershed divide (between the
Charles Street and O?dar Street CSSA), with little area tributary to the
site. The school sites, because of their largely pervious areas, contribute
little runoff to the combined sewer.
Surface storage and flow retention facilities are a good option when large
volumes of overland runoff or separate stormwater conduits are channeled to a
combined sewer. Retention in this situation will provide significant
reductions in peak sewer flows. Neither the available sites nor collection
system favor this type of facility in East Lansing.
* In-Svstem Controls. In-system controls would consist of a series of gates,
weirs, or diversions which slow the flow, in upstream portions of the
combined collectors. These measures are considered as part of in-line
storage options for each basin. In-system control will also include the
diversion of flows from the Main Interceptor to the MSU Interceptor.
* Additional Storage. The 1976 CSO Facilities Plan proposed an over sized
sewer with in-line storage. Control of CSO in Harrison and Charles Street
CSSA will require additional storage. Storage could be developed in an in-
line sewer or in off-line storage. A design level of protection from
overflows must be selected to size storage facilities.
* Additional Treatment. The treatment plant has significant capacity available
to treat wet weather flows that can be stored and gradually
released to the plant without overflowing the sewer system. Biological
treatment plants, especially those requiring nitrification, do not respond
readily to large variations in flow rates. East Lansing can operate the
existing plant within its design criteria at the higher long-term flow
rates which would be maintained if wet weather flows are stored and gradually
released for treatment. The plant is designed to hydraulically pass up to 40
MSD through the plant. This is the maximum flow the 54-inch influent sewer
can deliver. Limitations of the secondary process have been previously
discussed. No additional treatment is recommended, although increased storage
at the plant site should be implemented as previously discussed.
5-3
-------
BASIS OF ANALYSIS
The control strategy is based on existing information concerning the
collection systems documented in the System Inventory. The inventory also
documented treatment plant capacities, based on design criteria provided by
Hubbell, Roth, and Clark, Inc., and operational experience presented by waste-
water treatment plant staff. The inventory indicated that while the Main
Interceptor is at capacity, storage volume may be available in the combined
sewer collectors. The Michigan State Interceptor also has excess capacity
and some treatment plant capacity is available.
The sewer system analysis has been conducted using the Stormwater Management
Model, Version 4.3 (SWMM). It is important that it be recognized that actual
wastewater flow data in the East Lansing collection system is limited to pump
station records for two separate areas, and to influent flow data at the treat-
ment plant. A flow monitoring program should be conducted before any system
controls are designed and implemented to verify estimates developed on the
physical features of the system, and existing records.
Opportunities for overflow reduction are indicated by the source and loca-
tion of flow entering the collection system, a statistical analysis of rainfall
occurrence, and treatment plant capacity. These factors are described in the
following sections. In addition, the SWMM model of the collection system is
presented.
Dry Weather Flows
Dry weather flows from tributary interceptors and collectors and cumulative
flows in the Main Interceptor are listed on Table 5-2. The location of the
summaries are illustrated on Figure 5-1. From this summary, the following
conclusions may be made:
1) Dry weather flows in the 24-inch Main Interceptor are relatively close
to capacity;
2) The 33-inch Main Interceptor is at about half capacity in the segment
upstream of the point that the Harrison/Brody Interceptor joins the Main
Interceptor. Some wet weather capacity is available; and
3) The 54-inch Main Interceptor flows at about 30 percent capacity under dry
weather conditions. Treatment plant flow records for 1987 and 1988 indi-
cate that maximum flows at the plant do not exceed 23 million gallons per
day (MGD) during significant wet weather events. This is about 60 percent
of sewer capacity.
Treatment Capacity
The treatment plant is designed to hydraulically pass 40 MGD through the
secondary process. Tertiary filters are limited to 18.75 MGD. The East Lansing
plant is required to nitrify from May through October. Nitrification requires
longer sludge age. Washout of solids as a result of hydraulic overload of the
secondary clarifiers would reduce the ability of the plant to meet ammonia limits
on a consistent basis.
5-4
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-------
TABLE 5-2
DRY WEATHER FLOW VS. HYDRAULIC CAPACITY
Average Dry Average Cumulative Hydraulic
Weather Flow Flow in Interceptor Capacity
Location MGD MGD MGD
1. 24" Sanitary Collector1 1.0
2. Willraarth CSSA2 1.1
3. 24" Main Interceptor 2.1 2.5
4. Cedar Street CSSA2 0.4
5. 24" Main Interceptor 2.5 2.5
6. 27" Main Interceptor 2.5 5.0
7. 60" Charles St. Interceptor2 0.7
8. 33" Main Interceptor3 3.2 8.0
9. 30" MSU Sanitary4 0.7
10. 33" Main Interceptor5 3.9 8.0
11. 18" Harrison/Kellog Interceptor6 0.2
12. 33" Main Interceptor7 4.1 8.0
13. 27" MSU Sanitary4 0.2
14. 33" Main Interceptor8 4.3 8.0
15. 36" Harrison/Brody Interceptor9 2.5
16. 48" Main Interceptor 6.8 20.0
17. 48" MSU Interceptor10 4.7 28.5
18. 24" Sanitary Collector11 0.2
19. 54" Main Interceptor 11.7 40.0
1 Estimated flow from SWMM model output for the residential area of East Lansing, plus the
wastewater billing records for Meridian
2 Estimated flow from SWMM model
3 Between 007 and MSU sanitary sewer
4 Estimate based on reported annual Michigan State wastewater discharge to the sewers and the
approximate service area of the sewer
5 Between MSU sanitary sewer and Harrison/Kellog Interceptor
6 Estimate based on SWMM model for East Harrison subarea, and approximate service area of
adjacent Michigan State service area
7 Between Harrison/Kellog Interceptor and MSU sanitary sewer
8 Between MSU sanitary sewer and the Harrison/Brody Interceptor
9 Estimate based on the SWMM model output, estimated flow from Brody Dorm area presented in
"Wastewater Collection System Study of Woodinghara Pumping Station District and Harrison
Road District Brody Dorm Siphon", and average flow from the Woodinghara Pump Station Records
for 1988
10 Estimate based on reported annual Michigan State wastewater discharge to the sewers and the
approximate service area, plus the reported flows from the Hamilton road Pump Station
11 Estimate based on area
5 - 6
-------
The treatment plant has two aeration tanks permanently out of service in the
south plant. These have a storage volume of about 500,000 gallons. The north
plant has five tanks permanently out of service with about 500,000 gallons of
storage. This tankage has aeration equipment and could be converted into aerated
storage for wet weather flows, providing 3,000,000 gallons of storage. The treat-
ment plant has piping galleries connecting the different unit processes. East
Lansing should be able to add the piping and valves necessary to complete the
aeration tank conversion at a relatively modest cost.
The 5,000,000-gallon equalization basin is currently operated to dampen
diurnal flow variations. Levels are generally kept low to reduce aeration costs.
An operational protocol, specifying that the equalization basin be drawn down when
wet weather is expected, would ensure that additional storage for wet weather
flows is available. For purposes of this study, it is assumed that 3,000,000
gallons could be made available for wet weather storage in the equalization basin
by operating the plant to provide this additional storage when wet weather was
anticipated. Flow through the plant should be increased prior to rainfall, thus
making storage capacity available in the equalization tank.
The treatment plant has passed 23 M3D during wet weather events without
causing process upset. The plant is rated for 30 M3D maximum day treatment based
on the design report. Therefore, it is assumed 25 M3D can receive secondary
treatment without process upset for treatment during wet weather events. Filtra-
tion is limited to 18.75 M3D. Design capacity is 18.75 M3D, maximum monthly
average.
Therefore, the plant can provide secondary treatment for 25 MGD on a regular
basis and receive an additional 6 M3D into storage for a wet weather event. The
storage would not be available on subsequent wet weather days until dewatering of
stored wastewater was completed. Additional analysis of long-term rainfall records
is required to determine how quickly stored wastewater must be treated to provide
storage for subsequent events.
Rainfall Analysis
A rainfall analysis was performed on hourly precipitation data from the
Lansing Airport for the periods January 1951 through July 1954, and May 1959
through November 1988. Data was obtained from the National Oceanic and Atmos-
pheric Administration. The results of this analysis were used to select rainfall
events to simulate with the
Table 5-3 shows the distribution of events by volume over the period of
record. Also shown are the return period intervals for each range. The average
event duration was 6.30 hours, while the average time between events was 58.21
hours over the period of record. The average volume of an event was 0.23 inches.
The maximum volume for a single event was 4.95 inches over a 13-hour duration.
The maximum rainfall intensity which was recorded on an hourly basis during the
period of record was 2.48 inches per hour.
Storms were selected for events recorded during the period of record which had
typical intensities and durations for a particular rainfall volume. The events used
5-7
-------
Range of
Rainfall
Volume (in. )
0
.10
.20
.30
.40
.50
.60
.70
.80
.90
1.00
1.10
1.20
1.30
1.40
1.50
1.60
1.70
1.80
1.90
2.00
2.50
3.00
3.50
4.00
- .10
- .20
- .30
- .40
- .50
- .60
- .70
- .80
- .90
-1.00
- 1.10
- 1.20
- 1.30
- 1.40
- 1.50
- 1.60
- 1.70
- 1.80
- 1.90
-2.00
- 2.50
-3.00
- 3.50
- 4.00
- 4.50
4.50 - 5.00
TABLE 5-3
EAST LANSING, MICHIGAN
RAINFALL ANAYSIS
JANUARY 1951 THRODGH JULY 1954
AND
MAY 1959 THRODGH NOVEMBER 1988
Number of Events
Over the
Period of Record*
2276
669
364
279
161
140
93
83
48
48
42
18
27
28
16
14
8
7
5
5
9
7
4
0
1
1
Range of Calculated
Return Period**
(years)
0.01
0.
0.02
0.03
0.04
0.05
0.07
0.09
0.11
0.14
0.17
0.22
0.25
0.32
0.44
0.54
0.70
0.86
1.03
1.27
1.50
2.58
5.79
20
54
- 0.02
02
- 0.03
-0.04
- 0.05
- 0.07
- 0.09
- 0.11
- 0.13
- 0.17
- 0.21
-0.24
-0.30
- 0.42
- 0.53
-0.64
- 0.82
- 1.00
- 1.18
-1.44
- 2.39
- 4.92
- 9.01
.28
.08
Events
per
Year ***
71
21
11
9
5
4
3
3
1
1
1
* An event is defined by a minimum intervent time (dry hours between distinct
rainfall events) of six hours.
** Based on volume.
*** Based on 4,353 total events and 32 years, 1 month of rainfall records.
Source: National Oceanic and Atmospheric Administration
5 - 8
-------
in the SWMM modeling are shown in Table 5-4. These events were selected by
examining rainfall records. Only hourly rainfall data was available for this
study. Rainfall records which reflect more frequent measurements would likely show
higher short-term rainfall intensities and may result in greater overflows than the
amounts predicted by the model.
Flow volume and flow rate of runoff and wastewater in combined sewers is a
function of the intensity of the rainfall and the duration of the event, as well as
the total volume. The rainfall events selected to analyze the collection system
provide an estimate of overflow and peak flows which are specific to the intensity
of event and its duration. Events with similar volumes but different intensities
or durations will have different overflow characteristics. The four events
selected allow an examination of trends in combined sewer response to events of
different volume. Additional analysis of varying intensities and durations will
further refine the understanding of system response to different rainfall
conditions.
SWMM Modeling of Collection System
Combined sewer areas within East Lansing were modeled using the USEPA Storm
Water Management Model, Version 4.3 (SWMM). SWMM is a computer simulation model
that predicts hydrographs (graphs of flow versus time) based on rainfall data and
a characterization of the drainage area and sewer system.
For East Lansing, the model was used to:
1) Estimate the volume of combined sewage released to the Red Cedar River at
overflow structures for the selected rainfall events;
2) Estimate peak flow rates and the time of peak flow from overflow tributary
areas for selected rainfall events; and
3) Assess the potential for in-line storage within large capacity combined sewer
collectors.
The four rainfall events in Table 5-4 were simulated in the modeling effort.
The East Lansing combined sewer system was divided into six areas, each
tributary to a specific overflow structure. The tributary areas are identified on
Figure 5-2. Each tributary was further subdivided into subareas in order to
reflect contributions to different upstream locations in the combined sewer system.
The subareas are also identified in Figure 5-2.
Information regarding the area, percent imperviousness, and average surface
slope was gathered for each subarea and used as input data to the Runoff Block
of SWMM. With the SWMM model this information is used, together with the rainfall
data, to estimate hydrographs from each subarea.
5-9
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CITY OF
EAST LANSING
Michigan
SANITARY SEWEFC
ML' V
INTERCEPTORS.
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EAST-WEST BOUNDARY
AREA BOUNDARY
5 - 11
FIGURE 5-2
EAST LANSING OPERATIONAL PLAN
SWMM ANALYSIS AREAS
-------
The size, slcpe, and length of combined sewers linking the different subareas
was gathered and entered into the Transport Block of SWMM. The Transport Block
routes and combines subarea hydrographs developed in the Runoff Block.
Estimates of combined sewage overflow volumes were developed based on
hydrographs generated from SWMM modeling and estimated capacities of the
interceptor sewer. It was assumed that any flow that could be accepted by the
interceptor would be delivered and that any excess flow beyond the interceptor's
capacity would be released through an overflow.
Table 5-5 summarizes the results of the SWMM output as well as a summary of
key input data by drainage area. Shown are the area in acres and the average
percent imperviousness for each tributary area and the flow capacity limit to the
interceptor from each tributary area. Volumes are shown by rainfall event for the
total rainfall volume over the drainage area, the total estimated rain-induced flow
and the total estimated overflow. The flow contribution limit from each combined
sewer tributary area, as identified in Table 5-5, was estimated based on inter-
ceptor capacities and potential contributions from upstream sources, overflows
from tributary areas were estimated by subtracting the flow contribution limit from
the flow estimates developed for the area using SWMM.
Values for the time of concentration were estimated from the SWMM output for
each tributary area. These are shown in Table 5-6. These figures represent the
time of concentration for runoff from impervious areas only. The contribution
from the pervious areas would result in a later peak which is not of significance
in the analysis of the control of low flow rainfall events.
TABLE 5-6
ESTIMATED TIMES OF OQNCENTi&TICN
CSSA Time of Concentration (hours)
WilUnarth 1.7
radar 1.0
Charles 1.0
E. Harrison 1.7
W. Harrison 1.0
PROPOSED OCKEROL
Control strategies for each of the major service areas have been identified.
The overriding limitation in the East Lansing system is the capacity of the Main
Interceptor from the diversion structure for Outfall 013 of the Willmarth CSSA to
the point where the Brody/Harrison Interceptor joins the system, and discharges
to the 48-inch Main Interceptor segment. The Main Interceptor can handle little
flow beyond the normal diurnal fluctuations of dry weather flow.
5-12
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5 - 13
-------
The intent of the control strategy for the CSSA is to:
* Reduce flows in the Main Interceptor;
* Utilize the Michigan State Interceptor to the maximum extent practicable
for wet weather relief;
* Store a portion of wet weather flows in the large diameter combined sewer
collectors (in-line storage) until conveyance capacity is available in
the Main Interceptor;
* Store additional wet weather flow reaching the treatment plant in unused
aeration basins converted for storage and drawdown of the equalization
basin; and,
* Reduce wet weather flow through a program of inflow source reduction.
Significant unused conveyance capacity is apparently available in the 48-
inch MSU Interceptor. This assumption must be confirmed by system monitoring.
Excess infiltration and sewer inflow from the separate sewer service area in
Meridian Township would reduce available wet weather conveyance capacity in the
Michigan state Interceptor. Current agreements give Meridian Township rights to
discharge wastewater through the sewer. East Lansing does not have use of the
sewer. A summary of the current factors concerning the Michigan State Interceptor
are provided in Table 5-7. As stated in Chapter 3, East Lansing should negotiate
with both parties to obtain rights to utilize the 48-inch MSU Interceptor.
The strategy is defined for the different flow sources as follows:
Separate Sewer Area: WoodincflvBn Pump Station
The pump station was recently upgraded with an expanded wet well and
pumping capacity of 18.8 cfs (121 MGD) . Flow data and the design report for the
pump station indicate that significant infiltration/inflow of clearwater increases
the flow from this area from three to ten times dry weather flow during wet weather
events. In addition to source elimination previously discussed, East Lansing
should operate this system to retain flows during wet weather.
Consideration should be given to developing additional off-line storage for
this area. If flows are held back during a wet weather event, then additional
capacity in both the Harrison/Brody Interceptor and the Main Interceptor will be
available to accept flow from the Harrison West CSSA. Elimination of inflow
sources, and excess infiltration should be an integral part of the overflow control
program.
Separate sewer Ar^qg; Meridian Township/Hamilton Pump Station Service Area
Increased wet weather flow has also been observed through this pump station. A
program of infiltration/inflow control for this service area should be implemented
for this area as in the area served by the Woodingham Pump Station. Off-line
storage for wet weather flows could also be considered for this area.
5-14
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TABLE 5-7
FACTORS CONCERNING HSU INTERCEPTOR
Design Capacity: 44 cfs (28.5 MGD)
East Lansing Portion, transferred to 20 cfs (13 MGD)
Meridian Township (from 1961 contract)
MSU Portion 24 cfs (15.5 MGD)
Estimated MSU usage* - average 2.6 cfs (1.7 MGD)
peak 5.2 cfs (3.4 MGD)
Estimated current Meridian Township
usage - average 4.6 cfs (3.0 MGD)
peak 9.2 cfs (6.0 MGD)
Maximum treatment capacity at the plant**
- Meridian Township 7.7 cfs (5.0 MGD)
- MSU 9.2 cfs (6.0 MGD)
Unused capacity***
- Meridian Township 15.4 cfs (10 MGD)
- MSU 21.3 cfs (13.8 MGD)
TOTAL UNUSED CAPACITY 36.7 cfs (23.8 MGD)
* Estimated (43X of MSU flow discharged to the Main Interceptor)
** By contractual agreement
*** Assumes average flow conditions
5 - 15
-------
Michigan State University Separate Sewer Service Area. No physical changes to this
collection system are recommended at this time.
East Tanaincf/Mgridian Township S*araT'ate Sew*^ Ar^a TrHhut'-aTv to the Main
Interceptor. Flow from the separate area east of the Willmarth CSSA enters the
Main Interceptor system at the diversion structure for Outfall 013. Meridian
Township flow is estimated to be 0.5 MGD. East Lansing flows are also estimated
to be 0.5 MOD. This 1.0 MO) average flow should be diverted to the MSU Inter-
ceptor. There is a connection between the two systems at East Brookfield and
Grand River Avenue which has been bulkheaded. This bulkhead should be removed and
placed so that all separate area flow is conveyed through the Meridian Township
system to the MSU Interceptor. The 0.5 MGD from Meridian Township should be
allowable within existing agreements. East Lansing should obtain rights for
discharging its flow through the interceptor. This action will immediately reduce
downstream surcharging in the Main Interceptor.
Willmarth CSSA
The Willmarth CSSA is served by a major combined sewer collector which
bisects the area. Dry weather flow enters the Main Interceptor at a diversion
structure just south of Grand River Avenue.
Analysis of the system performance under selected rainfall conditions
indicate that Willmarth generates significant amounts of CSO relative to the other
CSSAs, as shown in Table 5-5 and 5-8. The maximum allowable contribution to the
interceptor sewer from Willmarth was estimated to be 2.5 cfs (1.6 MGD) . Actual
overflow amounts may differ depending on the ability of the interceptor to
surcharge without releasing flows to the river.
Only limited in-line storage potential appears to exist in the Willmarth CSSA
as noted in Table 5-9 based on the analysis of the 0.5 inch event.
Control of wet weather flows could be obtained by connecting the Willjnarth
CSSA to the MSU Interceptor. A connecting sewer running west to east along Grand
River Avenue to East Brookfield Drive (2400 feet) or running east on Grand River
Avenue and South on Hagedorn Road (2200 feet with a river crossing) could make this
connection. A control structure to limit flow to the capacity of the MSU Intercep-
tor would be required. Assuming the East Lansing separate sewer flow has been
routed through the MSU sewer, about 22 MGD (average flow) of capacity would be
available. Monitoring of flow in the MSU sewer would be required to ensure that
flows released from the combined area did not exceed the MSU Interceptor capacity
nor limit required capacity for University discharges. Monitoring equipment is
available to allow control of one location based on flows at another location.
Street CSSA
The Cedar Street CSSA is subdivided into east and west sections. The results
of the SWMM modeling of the system revealed that approximately 800,000 gallons of
unused 54-inch, 72-inch, and 78-inch sewer within the western portion of Orlrir CSSA
exists above the peak flow depth for the 0.5-inch rainfall event.
5-16
-------
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-------
TABLE 5-9
IN-LINE STORAGE CAPACITY
MAJOR COLLECTORS
Area
Willmarth
Length
(ft)
1000
Pipe
Diameter
(in)
54"
Volume Full
(gal)
120,000
Estimated
Excess Volume*
0.5" Storm
(gal)
65,000
Cedar
1100
1060
2670
54"
72"
78"
131,000
224,000
663,000
100,000
170,000
540,000
1,018,000
811,000
Charles
1800
60"
260,000
150,000
East Harrison
300
2'x2.5
<12,000
West Harrison 1800
1200
60"
72"
260,000
253,000
170,000
200,000
370,000
* Volume in sewer above maximum flow depth during 0.5 inch rainfall
event with average intensity of 0.17 in/hr; duration of 3 hours
5 - 18
-------
Approximately 0.9 million gallons of overflow was estimated to occur for the
same 0.5-inch event. Based on the modeling results, the overflow at Cedar, for the
0.5-inch event analyzed, could be reduced by approximately 90 percent if storage
capacity in the sewers were utilized.
The diversion structure to outfall 009 severely limits flow into the
interceptor. A 10-inch pipe transfers flow from the West Cedar branch to the
interceptor, a 12-inch pipe connects the East Cedar area. These small pipes limit
storage dewatering capabilities. Only 2.5 cfs (1.6 M3D) was estimated to be
available for flow from the Cedar Street CSSA to the interceptor.
If the Willmarth/MSU connection is made, the sewer should be extended 1100
feet west to connect with the West Cedar collector at Milford and Grand River, and
another 600 feet to the West Cedar collector at Durand and Grand River. Storage
and dewatering of the two combined service areas would have to be jointly operated.
Charles Street CSSA
It was apparent from SWM1 modeling analyses that the Charles Street. CSSA is
also a major source of combined sewer overflows, as shown in Table 5-5. However,
the contribution from Charles Street to the interceptor was estimated to be less
since it appears for the events examined the interceptor can accept up to 5.3 cfs
(3.4 M3D) from Charles Street, as compared to 2.5 cfs (1.6 M3D) from Willmarth.
Only limited in-line storage appears to be available within the Charles CSSA
sewers, as identified in Table 5-9 based on analysis of the 0.5 inch event.
Significant overflow reduction may require off-line storage. locations for
this storage appear to be limited to University property, adjacent to the 60-inch
Charles Street Interceptor. This interceptor is also the sewer with capacity to
provide storage. Control structures for storage will require additional construc-
tion near the 007 diversion structure. This structure dates to 1927, when the
interceptor was originally constructed. Its location in the flood plain, with
brick construction, indicates that replacement should be considered as part of the
design of the storage control structure.
Harrison Road CSSA
The Harrison Road CSSA was run on the SWMM modeled as two separate areas.
The Combined sewer system within the Harrison CSSA is complex. Flow routing, based
on available sewer records, was difficult to predict. East Harrison is considered
as the area tributary to the Kellog Siphon while West Harrison is considered as the
area tributary to the Brody Dorm Siphon.
During rainfall events, all of the interceptor capacity upstream and
immediately downstream of the Kellog Siphon connection to the interceptor was
assumed to be taken up by upstream sources. All of the combined sewer flow from
East Harrison was thus assumed to overflow during a rainfall event since there
appeared to be no additional interceptor capacity available.
5-19
-------
Based an modeling efforts, East Harrison provides the least potential for in-
line storage of the combined sewer service areas. Relatively small rectangular
and circular sewers are used within East Harrison. Off-line storage or additional
hydraulic capacity in the interceptor downstream of the Kellog Siphon may be the
only alternatives available for reducing the combined sewage contribution from East
Harrison.
West Harrison was estimated to contribute the greatest amount of flow to the
interceptor sewer for rainfall events modeled. Approximately 20 cfs (12.9 M3D)
was estimated to be available at the interceptor for flow from West Harrison.
As with other combined sewer areas, the amount of overflow from West Harrison was
considered as the flow from the area which exceeded the estimated interceptor
sewer capacity. This assumption may underestimate the actual overflow from West
Harrison because of the overflow control device at Michigan and Harrison. The top
of the overflow weir is only about one foot above the pipe invert. Nearly all of
the flow from the eastern branch of West Harrison likely overflows during a storm
event.
Significant in-line storage capacity appears to exist within the West
Harrison large diameter sewers, as noted in Table 5-9. This storage could be
utilized by constructing an adjustable weir or gate at the Michigan and Harrison
overflow structure. Based on the modeling performed for a 0.5-inch rainfall event,
the overflow volume from West Harrison could be reduced for a storm of this volume
and intensity by approximately one-third if in-line storage was used.
The Hubbell, Roth, Clark Study also recommended off-line storage, to be
located at Harrison and Michigan on the north bank of the Red Cedar River. A
storage volume of 2 to 3 million gallons would be necessary. With cooperation of
the University, open space directly south across the Red f*yfor River could
potentially be utilized for storage. This site, along with others previously
suggested, should be evaluated in further detail. Storage facilities need not be a
large visible structure; generally they are located below ground and covered. A
small structure with street access for maintenance and cleaning would be required.
PERFORMANCE OF PROPOSED SYSTEM
The proposed system operation will provide greatest control for low inten-
sity, lower volume events. However, control of the precipitation events will
potentially eliminate or reduce the volume of a significant number of CSO events.
Of the 65 estimated annual CSOs, 46 would occur as a result of rainfall between
o.l and 0.5 inches. Another 12 occur because of rainfall between 0.5 and 1.0
inches of precipitation. Control of these lower volume rainfall events would
provide elimination or reduction of 70 to 90 percent of the overflow events.
The ability to use plant capacity is dependent on being able to route the
flow there, and distribute it into the plant for treatment in a controlled fashion.
The proposed operational plan provides routing of wet weather flows to sewers with
hydraulic capacity, storage of flows in the combined collector system for later
5-20
-------
release, storage in off-line facility, and additional storage at the treatment
plant. Available in-line storage in contained sewer collectors is variable by
basin, as illustrated on Table 5-9. Storage of over 800,000 gallons was found to
be available in the Charles Street Interceptor for the 0.5-inch event evaluated
using the SWMM model, while the Willmarth CSSA had only 65,000 gallons available
for the same event. Using the proposed operational plan, virtually all of the
overflow volume could be stored in Cedar CSSA during the event. Flow from
Willmarth could be routed to the Michigan State Interceptor. As interceptor and
treatment plant capacity was available, stored combined sewer overflow (CSO) from
the neriay CSSA would be released to the MSU Interceptor.
Capacity made available by rerouting may allow some of the CSO beyond the
150,000 gallons of storage in the Charles Street CSSA to be conveyed through the
Main Interceptor. About 40 percent of the event would be stored in the collector
system; the remainder would be stored in off-line storage. Off-line storage with
later release would also be utilized for the East Harrison subarea. Figure 5-3
illustrates a potential flow routing, using the 0.5 inch storm analyzed as an
example. Flow rates at different points in the system are illustrated.
OPERATIONAL SYSTEM REQUIREMENTS
A detailed control strategy which defines priorities for storing, rerouting,
and releasing of overflow must be developed. Control criteria would include
prevention of system back-ups, and protection of the plant treatment process, while
maximizing capture of CSO. Operation of this system will require remote controls
because response times of manual control would not be sufficient. Controls would
operate from monitoring of the collection system at key points.
Additional facilities required to implement the operational plan have been
discussed. A summary of these include:
* Diversion structures with gating and controllers at a minimum of seven
locations;
These are:
1. The 24-inch separate sewer at East Brookfield and Grand River Avenue,
to Meridian Township, and the Michigan State Interceptor;
2. Willmarth collector at Grand River Avenue;
3. Cftdar East at Milford and Grand River Avenue;
4. Cedar West at Durand and Grand River Avenue;
5. Control gate upstream of the diversion structure for Outfall 007;
6. Diversion to off-line storage for East Harrison at about Harrison
and Michigan; and,
7. Control structure for storage of West Harrison flows.
5-21
-------
-------
* Other passive structures may be necessary upstream in the cantoned
sewer collectors to retard peak flow rates;
* A sewer connection from the Cedar West diversion to the connection
with the Meridian Township sewer tributary to the Michigan State
Interceptor;
* Reconstruction of unused aeration basins to provide additional
storage at the plant; and,
* Off-line storage facilities for the Harrison East, Harrison West, and
Charles Street CSSA.
High Water Control - Floodproofing
As illustrated in Chapter 2, the Main Interceptor lies in the 100-year
flood plain from approximately outfall 009 west. The 30-inch Michigan State
sanitary collector is also indicated to be in the flood plain. Treatment plant
staff have indicated that influent flows to the treatment plant increase during
periods of high levels in the Red Cedar River. River inflow was suggested as a
source of increased flow. River inflow will take interceptor and treatment
capacity as other clear water sources. To define the extent of river inflow,
the following actions are recommended:
1) Record observed river inflow during the outfall monitoring. Record
the cause; and,
2) Correlate observed river inflow to plant influent flows.
River inflow has been attributed by staff to debris jamming flapgates open.
Measures for removing the debris, or keeping debris from the flapgates should
be investigated.
Manholes in the flood plain may also be a source of river inflow. These
manholes should be inspected and categorized as to flood potential. A program
replacing interceptor manholes with bolt down floodproof covers should be
implemented.
System Flow Monitoring
Flow monitoring data must be collected to refine estimates of system flow for
wet and dry weather, and to characterize diurnal variations. This information will
be necessary to implement the plan. Precipitation data should be collected in the
area being monitored to correlate wet weather flows to the basin flows observed.
At a minimum the following sewers should be monitored to characterize the
interceptor flow:
1) 36-inch Brody/Harrison Interceptor, south of river;
5-23
-------
2) 48-inch MSU Interceptor, near the junction with the Main Interceptor;
3) 33-inch Main Interceptor west of 3M siphon and junction with 30-inch
MSU collector; and
4) 27-inch Main Interceptor upstream of diversion structure for
Outfall 007.
For the Charles, Cedar, and Willmarth CSSAs, there is minimal interceptor
capacity available beyond dry weather flow. Monitoring of wet weather flow in
the major collectors just upstream of the diversion structures will approximate
overflow volume.
The Harrison Road CSSA is more complex. Overflow volume for West Harrison
could be determined by monitoring the 36-inch collector in Michigan Avenue, the
60-inch collector in Kensington, and the 60-inch collector in Harrison. The
flow in the Brody/Harrison Interceptor, just south of the diversion in Michigan
Avenue, is a function of the flow from three collectors plus flow from Woodingham
Pump Station. Overflow at Outfall 010 would equal the total of the three col-
lectors minus the Brody/Harrison total flow minus Woodingham Pump Station flow.
East Harrison flow could be estimated by monitoring flow in the two tribu-
tary collectors minus flow in the Harrison/Rellog Interceptor.
Additional monitoring upstream in the major collector should be conducted
for design of the storage-release plan for each CSSA. This data would be used
to confirm the outing and timing of flows through the collection system.
Monitoring data is essential to system control design. Diurnal flow
variations are significant, so control strategies will have to recognize the
varying capacities over the course of the day. System monitoring will iden-
tify these patterns for incorporation into the control strategy for CSO control.
CONCLUSION
The proposed control strategy recommends a combination of storage in the
large diameter combined sewer collectors, rerouting of flows to the Michigan
State Interceptor, and use of out-of-service aeration tanks for wet weather
flow storage at the treatment plant to reduce overflows.
Off-line storage would further decrease the number and volume of overflows.
It is estimated that 46 to 58 events per year could be reduced or eliminated
with this operational plan. The operational plan has the greatest effect on
smaller volume, lower intensity events. large volume, or high intensity events
will continue to overflow, although some CSO capture would occur.
System monitoring is required to confirm and refine flows in the inter-
ceptor system, and the combined sewer service areas.
5-24
-------
Additional analysis of long-term rainfall records is necessary to obtain
an estimate of the overall reduction in CSO volume and occurrence which could
be achieved utilizing the proposed operational plan. This reduction should
then be assessed relative to cost of facilities and the additional operation
and maintenance costs necessary to implement the plan. Detailed planning and
additional hydraulic analysis of alternate rainfall volumes, intensities, and
durations will be necessary before implementation as well.
5-25
-------
Chapter 6
AND SCHEDDI£
An implementation plan and proposed schedule have been prepared for the
Combined Sewer Operational Plan for East Lansing. The plan has been divided
into twelve major activities. These activities may be implemented over a
period of about four and one-half years. It is anticipated that pollution
abatement benefits would begin to accrue within 18 to 24 months of the
initiation of activities.
A schedule for implementing the twelve major activities is shown in
Figure 6-1. Certain activities are deferred until information is available
from other related activities which is reflected in the schedule. The dura-
tions of activities are estimated based on project scope and continuous pro-
gress toward completion. While the start date for plan implementation has
been set for September 1989, numerous factors such as budget, weather, and
negotiations with other parties could alter the schedule duration as pre-
sented.
The detailed description of the twelve major activities provided in
Table 6-1 includes sequential subactivities, approximate time frames, and
commentary concerning the subactivities. More detailed tasks would be
developed for implementation of each of the tasks.
The activities described here are intended to implement reconimendations
made in Chapters 3, 4 and 5. Short-term actions such as the changes to
ordinances may be initiated immediately, and achieve benefits as scon as
they are in place and enforced. Other activities, such as development of
the in-line storage with wet weather diversion as proposed for Cedar Street
and Willmarth CSSAs, are longer term activities. They require system moni-
toring, some facility planning and design and construction to be fully
implemented. The following sections describe the general areas of the plan
improvements.
SHORT-TEPM ACTIONS
Initial activities include revisions to the sewer ordinance and service
contract revisions (Activities 1 and 2) . Some of these revisions, such as
use of the MSU Interceptor are prerequisites to plan implementation.
Another early activity (No. 4) is revision of overflow diversion structure
010 to achieve greater in-line storage in the Harrison CSSA. Investigations
to modify this structure in this way, possibly combining 010 with the
diversion structure to Outfalls Oil and 012, have been initiated. The
schedule proposes that these modifications be completed before monitoring
is conducted in the Harrison CSSA. The diversion structure for Outfall 010
should be designed to be compatible with alternate in-line storage or off-line
storage. The SWMM analysis indicated off-line storage would be desirable for
this service area.
The schedule shows an analysis of existing separate sewer systems flow
6-1
-------
records from puirp stations to better define the magnitude of infiltration and
inflow in the collection system (Activity 9) . Development of an I/I control
program is included in this activity. This examination of records will
supplement some of the interceptor monitoring.
Additions to the maintenance program may be initiated immediately upon
plan adoption. This activity included the identification of structures in
the flood plain and the long-term program to floodproof them.
LONG^TERM ACTIONS
A monitoring program is the first subactivity within the interceptor and
CSSA activities. Interceptor monitoring (Activity 3) is scheduled first, to
identify if assumptions on interceptor flows are correct. Monitoring would
occur in spring and early summer of 1990. This time period would typically
provide sufficient variable rainfall events to characterize the system flows.
A later subactivity includes the separate sewer diversion at East Brookf ield
and Grand River Avenue.
Monitoring would then follow in the fiarfai- street CSSA, where in-line
storage appears to be most available (Activity 5) . Monitoring and control
structures with an operating system would be tested first here. Pollutant
reduction would be achieved with initiation of overflow control in this
service area.
Monitoring would then be conducted in the Harrison, Willmarth, and
Charles Street CSSAs respectively (Activities 6 and 7) . Spacing the monitor-
ing provides the potential for city maintenance crews to conduct the program.
It also means that less monitoring equipment needs to be purchased or leased.
Rather, the equipment can be moved from one area to the next.
Treatment plant modifications can be completed independently of sewer
system improvements although they should be in place before major wet weather
diversions are begun. The schedule shows the additional storage in aeration
basins being in place by mid 1991. This would allow the plant personnel to
experiment with use of the storage before significant additional wet weather
flows can be routed to the plant.
The latest activities on the schedule are the design and construction of
the relief sewer from Cfriar and Willmarth CSSAs to the MSU Interceptor, and
the off-line storage for Harrison and Charles Street CSSAs. Both facilities
are dependent on monitoring data. Design criteria for each of these could
also be dependent on final requirements for CSO control to be issued by MDNR.
Both facilities will require some facilities planning. For off-line storage,
selection of a site will likely require alternative analysis with public
involvement. Off-line storage design will likely have structural requirements
which are site specific.
Summary
The Combined Sewer Operational Plan for East Lansing is implementable,
provided the schedule recognizes the resources available to the City of East
Lansing. Segments of the plan have been identified which can be initiated to
provide early benefits of the plan. Detailed analysis of individual, activi-
ties may indicate alternate schedule durations.
6 - 2
-------
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TABLE 6-1
Iitplementation Activities
Action
Approximate
Subactivitv
1. Sewer Ordi- a. Draft proposed
nance Revision ordinances
Time Frame
1-2 months
b. Public education 2-3 months
2. Service Con-
tract Revision
c.
a.
b.
c.
d.
3. Monitoring
of the Inter-
ceptor system
Comment
Includes disconnection of
roof drains in the CSSA,
disconnection of sump
pumps where practical,
separate building
laterals for redevelop-
ment in the CSSA.
Ordinance adoption 2-4 months
and enforcement
Draft proposed 1-2 months
amendments to the
current service
contract
Present amend- 2-6 months
ments to Meridian
Township and negotiate
proposed changes
Includes clear water
reduction requirements,
new sewer construction
performance criteria,
sewer plan review
records, and diversion
to the Michigan State
Interceptor at
East Brookfield and
Grand River Avenue.
18 months
Begin operation
under the amended
ordinance
Negotiate and
revise contract
with MSU Modi-
fications
a. Design monitoring 2-4 months
program
1 year from Individual items may be
start of nego- implemented independent-
tiations ly if one proves dif-
ficult to negotiate.
Concurrent with other
negotiations. Includes
use of MSU Interceptor
and maintenance easements.
Includes identification
of monitoring locations,
placement of weirs, etc.
purchase or lease of
monitoring equipment, and
contracting for outside
assistance if required.
Monitoring in sewers not
owned by East Lansing
should be arranged.
Rainfall records are
required here.
6-4
-------
Action
TKBLE 6-1 (Gent.)
Implementation Activities
Approximate
Subactivity Time Frame
b. Conduct monitoring 2-4 months
c. Interpret data 1-2 months
d. Refine detailed 1 month
operational plan
for the interceptors
data.
e. Design structure 4-6 months
to divert separate
sewer flow to MSU
interceptor at East
Brookfield and
Grand River
f. Construct diver- 4-6 months
sion structure
4. Monitoring/ a. Design service 1-2 months
Analysis/Modifi- survey and moni-
cations in the toring program
Harrison CSSA
b. Inventory service 2-3 months
connections eleva-
tions
c. Field inspect 1 month
structure 011/012
d. Design new over-
flow at structure
010 control
2-3 months
Onmient
Monitoring should be ex-
tended to define dry wea-
ther flow patterns in the
interceptors, and flow
patterns for a range of
rainfall events.
Analyze flow data. Redefine
interceptor capabilities.
Refine the operational plan
based on the monitoring
Includes a field survey
and monitoring. Includes
activities identified in
3.a.
location of service connec-
tions may limit in-line
storage potential.
Determine potential for con-
nection to 010.
Control structure should
maximize in-line storage. A
control structure in Michiga/V
Street where the Harrison
CSSA is connected to the
Harrison Brody Interceptor
will probably be required as
well.
6-5
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Action
5. Monitoring/
Analysis of
Street CSSA
TBHEE 6-1 (cent.)
Inclementation Activities
Subactivitv
Approximate
Time Frame
e. Install new 2-3 months
overflow control
trol in 010
f. Interpret data
g. Refine oper-
tional plan for
Harrison CSSA
1-2 months
2 months
a. Survey of service 1-3 months
area and design of
the monitoring
program
b. Conduct monitor- 2-4 months
ing
c. Interpret data
1-2 months
d. Refine opera- 2 months
tional plan for
Odar Street CSSA
e. Design control
structures and
control system
4-6 months
This service area should be
monitored after new overflow
structure is in place.
Define flow patterns during
rainfall events to determine
additional storage potential
or requirements.
In-line storage potential
refined based on observed
wet weather flows. Off-
line storage needs identified.
Monitoring should define/
confirm storage potential,
and the wet weather flow
patterns at overflow struc-
ture 009. Includes activi-
ties identified in 3.a.
Survey of connections to
evaluate back-up potential.
Wet and dry weather flow
characteristics should be
identified.
Interpret flow patterns to
define available in-line
storage.
Strategy for storage/release
of wet weather flow utilizing
in-line storage would be
developed. Strategy flexible
to utilize Main interceptor
and eventual connection to
MSU Interceptor. Identify
necessary control structure.
Design must consider poten-
tial from back-up as well as
in-line storage. Discharge
stored flows to interceptor
system as capacity is
available.
6-6
-------
TABLE 6-1 (cent.)
Implementation
Subactivitv
Approximate
Time Frame
f. Construct control 8-12 months
structures
6. Monitoring/ a. Survey of service 1-3 months
Analysis/Jtodifi- area and design
cations of of monitoring
Willmarth CSSA program
b. Conduct monitor- 2-4 months
ing
c. Interpret data 1-2 months
d. Refine opera- 2 months
tional plan for
Willmarth CSSA
e. Design control
structure and
control system
f. Construct control
structures
4-6 months
8-12 months
7. Monitoring/ a. Survey of service
Analysis/Modifi- area design moni-
cations of Charles toring program
Street CSSA
b. Conduct monitor-
ing
1-3 months
2-4 months
Comment
Completed system provides
in-line storage with a con-
trol system to maximize over-
flow reduction while protect-
ing users from back-ups.
Similar to 5.a.
Similar to 5.b.
Wet and dry weather flow
patterns at structure 013
should be defined, along with
any in-line storage potential.
Determine what in-line
storage capacity should
be utilized, a plan for wet
weather diversion to the MSU
Interceptor.
Similar to 5.e.
Construction would be in
conjunction with a wet
weather relief sewer to the
proposed diversion structure
at East Brookfield and Grand
River Avenue.
Similar to 5.a.
Similar to 5.b.
6-7
-------
Action
8. Development
of Off-line
Storage
TABLE 6-1 (cent.)
Implementation Activities
Subactivity
c. Interpret data
Approximate
Time Frame
1-2 months
d. Refine opera- 2 months
tional plan for
Charles Street CSSA
e. Design control 4-6 months
structures and
control systems
f. Construction of 8-12 months
control structures
a. Review monitoring 1 month
records for
Harrison and Charles
Street CSSA
b. Determine design 1-2 months
criteria for over-
flow capture
c. Facility plan for 6 months
siting of off-
line storage
d. Design off-line
storage
e. Obtain sites for
off-line storage
f. Construction of
off-line storage
4-8 months
6-12 months
12-24 months
Comment
Wet and dry weather flow
patterns at structure 007
should be defined, along
with any in-line storage
potential.
Determine in in-line storage
may be available. Develop
in-line storage strategy if
it can be utilized.
Structures and controls for
in-line storage. This task
will be done only if suffi-
cient storage potential is
present.
As above.
Use monitoring data to
refine system.
Long-term rainfall runoff
records examined.
d and e concurrent
activities.
6-8
-------
Action
Analysis of
Infiltration/
Inflow from
Separate Areas
10. Aeration
Basin Conversion
at the Treatment
Plant
TABLE 6-1 (ocnt.)
Implementation Activities
Subactivitv
Approximate
Time Frame
1-2 months
a. Review wet
weather/dry
weather flow
records for the
Woodingham and
Hamilton Road
Pump Stations.
Correlate precipita-
tion records to flow
records, and the inter-
ceptor monitoring program
b. Evaluate impact 1-2 months
of wet weather
separate system
on interceptor
system flow
c. Develop program 2-4 months
for inflow reduc-
tion in all sepa-
rate service areas
d. Public involve- 3-4 months
ment program
Comment
Include any bypass informa-
tion as well.
Education and voluntary
compliance.
e. Inspection and man-
datory compliance
f. Monitor to deter-
mine effectiveness
of program
a. Develop wet
weather storage/
treatment opera-
tional plan
b. Design piping
modifications and
controls
12-18 months
2 months
3 months
c. Construction
9-12 months
6-9
-------
6-1 (oont.)
Inplementation Activities
Action
11. Relief Sewer a.
Connection:
Odar Street CSSA
and Willmarth
CSSA to Diversion
at East Brook- b.
field and Grand
River Avenue c.
12. Maintenance/ a.
Flood Proofing
Approximate
Subactivitv
Develop design
criteria
Design sewer
Construct sewer
Incorporate addi-
tional reporting
reocninendations
Inspect manholes
and structures in
flood plain
List manholes and
structures for
floodproofing
Floodproof struc-
tures in flood
Time Frame
1 month
4-6 months
6-12 months
3 months
6 months
1 month
24 months
Qjuiient
Design based on monitoring
data. It should consider
conveyance and storage if
desired.
Includes necessary controls.
Recommendations from
Chapter 4.
6-10
-------
APPENDIX 1
LIST OF PREPARERS
-------
APPENDIX 1
LIST OF PREPARERS
This Combined Sewer Operational Plan is published by the United States
Environmental Protection Agency (USEPA) Region V. It was prepared by Triad
Engineering Incorporated, Milwaukee, Wisconsin, for Science Applications
International Corporation (SAIC), McLean, Virginia, under EPA Contract
No. 68-04-5041, W.A. No. 33 from the Great Lakes National Program Office.
Staff from USEPA, SAIC, and Triad Engineering involved in preparation of
the Combined Sewer Operational Plan included:
U.S. Envirurimental Protection Agency
Russell Martin Work Assignment Manager
Carolyn Bury Project Officer
Science Applications International Corporation
Carl Mitcfrell Project Administrator
Michele Leslie Contract Administrator
Triad Engineering Incorporated
Thomas Meinholz Project Manager
Brandon Kbltz Principal Investigator
Mark Miller Quality Control
Daniel Brady Project Engineer/Hydraulic Analysis
Steven Lepak Project Engineer
Renee Smits Project Engineer
Cindy Selas Project Engineer
Michele Pluta Technician
Michael Sylvester Graphics
Larry Jiles Graphics
-------
REFERENCES (cont.)
USEPA. 1988. Storm Water Management Model, Version 4. Users Manual. Office
of Research and Development, USEPA, Athens, Georgia.
USEPA, 1988. Storm Water Management Model User's Manual Version 4: EXTRAN
Addendum. Office of Research and Development. USEPA Athens, Georgia.
USEPA. 1986. Technical Guidance for Use in the Development of a Combined
Sewer System Operational Plan. Region V, Municipal Facilities Branch.
Design/Construction Unit. Special Evaluation Project Team.
Wanielista, Martin P. 1979. Storm Water Management. Quantity and Quality.
Ann Arbor Science Publishers Inc. Ann Arbor, Michigan.
-------
REFERENCES
Chow, Ven Te. 1964. Handbook of Applied Hydrology. McGraw-Hill Book Company,
New York, New York.
City of East Lansing. Forms for maintenance records, printouts of computer-
ized maintenance data, overflow reporting forms, sewer mappings, and
sewer construction record drawings.
Hubbell, Roth, and Clark, Inc. 1976. Facilities Plan for the City of East
Lansing, Michigan. Combined Storm Water Control Facilities.
Hubbell, Roth, and Clark, Inc. 1985. Sanitary Sewer Study for the Woodingham
Pump Station Service Area. Prepared for City of East Lansing.
Hubbell, Roth, and Clark, Inc. 1987. Wastewater Collection System Study of
Woodingham Pumping Station District and Harrison Road District Brody Dorm
Siphon. Prepared for City of East Lansing.
Hubbell, Roth, and Clark, Inc. 1972. "Discussion of Design Criteria for the
City of East Lansing Michigan Wastewater Treatment Plant."
Hubbell, Roth, and Clark, Inc. O&M Manual for the East Lansing Wastewater
Treatment Plant. (Chapter 2)
Hubbell, Roth, and Clark, Inc. 1988. Wastewater Treatment Plant Study of
Sewage Sludge Dewatering with Belt Filter Presses. Prepared for City of
East Lansing.
State of Michigan, Department of Natural Resources. 1988. "NPDES Permit No.
MI0022853."
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