The Birmingham Combined
Sewer Overflow (CSO) control facilities were constructed
as part of an $82 million national demonstration project.
The demonstration project is a three-phase project
aimed at eliminating CSOs in the Rouge River watershed.
The Birmingham Retention Treatment Basin (RTB) and
Tunnel were constructed under the second phase of the project,
which implemented CSO controls. Phase I included
monitoring and optimizing existing combined sewer systems
and planning for CSO controls. Phase III evaluates
the results of Phase II CSO controls and initiates further
controls (if necessary) to meet water quality standards.
The Birmingham RTB
and Tunnel service a 1,185-acre watershed, treating approximately
230 million gallons of CSO annually, of which 50 million
gallons are discharged to the Rouge River. The RTB
has a capacity of 5.5 million gallons and is 266' x 147'
x 20'. The facilities are designed to provide 30
minutes detention of the 1-year, 1-hour storm (1.0”).
The RTB receives gravity
flow from the 12' x 18' influent sewer. Two separate
cells are sequentially filled, as the facility provides
disinfection, settling and skimming. Flow exceeding the
storage capacity of the two cells is screened through 3/4”
x 3-3/4” openings and overflows via weir troughs to an effluent
channel that discharges to the Rouge River. Retained
flow in the RTB is pumped back into the Evergreen Interceptor
sewer system for treatment at the Detroit POTW. After
the basin is dewatered, a pivoting trough flushing system
is used to flush any remaining sediment from the tank bottom
to the interceptor sewer.
Construction of the
RTB was substantially completed in December 1997.
Located within the Birmingham Municipal Park, the control
building was designed to resemble a gristmill and extensive
woodlands landscaping was completed in order to blend with
the aesthetics of the site.
The Birmingham RTB instrumentation and controls are relayed
into Oakland County's Supervisory Control and Data Acquisition
(SCADA) system. This allows the County to monitor the
facility from a remote location and optimally operate the