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Combined Sewer Overflow Program
Background
Combined
sewer systems (CSS) are wastewater collection systems designed to convey
sanitary sewage and storm water (surface drainage from rainfall or snowmelt) in
a single pipe to a treatment facility. In periods of rainfall or snowmelt,
total wastewater flows can exceed the capacity of the CSS and/or the treatment
facility. When this occurs, the CSS is designed to overflow directly to
surface water bodies, such as lakes, rivers, and streams. These combined
sewer overflows (CSO's) can be a major source of pollution in communities served
by CSS's.
It
is difficult to quantify CSO impacts on receiving water quality and the
site-specific variability in the volume, frequency, and characteristics of CSO's. The financial costs of correcting CSO effects can also adversely impact a
community. In order to aid the states and communities, a CSO Control
Policy was published in the Federal Register on April 19,
1994. The policy is to:
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Provide
guidance to permittees with CSO's, NPDES permitting and enforcement
authorities, and State water quality standards (WQS) authorities.
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Ensure
coordination among the appropriate parties in planning, selecting,
designing, and implementing CSO management practices and controls to meet
the requirements of the Clean Water Act.
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Ensure
public involvement during the decision-making process.
A
key element of the CSO Policy is the permittees' implementation of the NINE
MINIMUM CONTROLS (NMC), which are technology-based actions or measures designed
to reduce CSO's and their effects on receiving water quality. Please refer
to POLICIES AND RESOLUTIONS for a detailed list of the NINE MINIMUM CONTROLS.
WWMA
Requirements
Manor
Borough and North Irwin Borough are the two areas in the WWMA system that
maintain combined sewers. There are three CSO structures on the system at
the points of connection to the WWMA interceptor sewers. One CSO structure
is located in Irwin and two structures are located in Manor. Monitoring of
the overflow points in each structure has been ongoing since October
1998.
The
WWMA's new NPDES permit became effective on August 1, 1998. Part C of the
permit requires that the Authority submit a report to the PaDEP by August 1,
2000. This report must provide documentation demonstrating implementation
and compliance with the NMC's required on a system-wide basis. Additionally, this report must include schedules for completing minor
construction activities associated with implementing the NMC's.
The
NINE MINIMUM CONTROLS are listed under POLICIES AND PROCEDURES and, as you select
each one, will briefly describe the type of documentation that must be provided
to comply with the requirements of the NPDES permit.
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