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Compliance and Enforcement Annual Results:
Important Environmental Problems / National Priorities
FY2006 Annual Results Topics
Priority: Municipal Sewer Overflows
(Combined Sewer Overflows)
(Sanitary Sewer Overflows)
Problem: Combined sewer overflows (CSOs) cause environmental problems when heavy rainfall exceeds the storage capacity of pipes and/or water treatment plants, discharging untreated sewage, stormwater, toxic materials, and industrial wastewater into rivers, lakes, and oceans. Untreated sewage contains high levels of nutrients which cause low oxygen levels resulting in dead zones in aquatic environments and fish mortality. Bacteria residing in untreated sewage overflows can contaminate the public drinking water supply, endanger human health for individuals participating in recreational activities such as swimming and boating, and limit access to beaches. Fish and wildlife advisories often result from bacterial contamination of seafood. CSOs pose particularly significant risks to human health when this activity occurs near sources of drinking water given that the discharge often contains a high concentration of bacteria and pathogens.
Similarly, when sanitary sewer systems that collect and transport sewage to public water treatment facilities release untreated sewage into local rivers, streams, and coastal zones during particularly high rainfall, and when equipment, system design, operation, and maintenance is faulty, environmental damage and threats to human health can occur. Bacteria, pathogens, nutrients, untreated industrial wastes, oil, pesticides, wastewater solids, and debris enter waterways when sanitary sewers overflow into waterways causing human health risks including diseases that range in severity from mild gastroenteritis to life-threatening ailments, such as cholera and infectious hepatitis. EPA focuses on sanitary sewer systems that are near public drinking water intakes, endangered and threatened species and habitats, national marine sanctuaries, commercial fishing sites and shellfish beds, waters designated as "outstanding national resource waters," and where waterborne recreational activities such as swimming and boating occur. Areas with prior water quality impairment also receive prioritized attention.
Key Results:
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Case Highlights:
CSOs:
Massachusetts Water Resources Authority (MWRA) will implement additional controls to further reduce overflows to the Charles River . Ongoing construction projects along with newly proposed work will reduce the planned volume of discharges into the Charles from 28 million gallons to a future total of approximately 7.8 million gallons per year. [More Information]
SSOs:
Washington Suburban Sanitary Commission (WSSC) will reduce raw sewage discharges by more than 26 million gallons per year and eliminate basement backups caused by inadequate capacity or poor operation and maintenance at a cost of $200 million. WSSC must also implement emergency response and cleanup programs to address all overflows and will undertake a monitoring program in the Anacostia River . WSSC will pay a $1.1 million civil penalty and will spend over $4 million on supplemental environmental projects . [More Information]
Annual Results by Fiscal Year:
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