Wastewater Treatment

Our mission is to operate and maintain wastewater treatment plants to produce clean water that meets all regulatory requirements for discharging to waters of the State of Maryland; to utilize the biosolids generated in the treatment process in an environmentally beneficial manner; and to operate and maintain numerous wastewater pumping stations to transport wastewater without overflows. We will accomplish our mission safely, cost effectively, and in a manner that serves our customers well and protects the environment.

WSSC operates and maintains six wastewater treatment plants. The Western Branch, Piscataway, Parkway, Seneca, Damascus and Hyattstown treatment plants have a total capacity to handle 89 million gallons of wastewater per day.  The remainder of the wastewater from our service area is treated at the Blue Plains wastewater treatment plant in the District of Columbia. 

View a brief movie on wastewater treatment (.wmv)

Wastewater treatment plant process


Part of the process of wastewater treatment creates biosolids. Biosolids are treated wastewater sludge. Biosolids can begin to form when wastewater is pre-treated before entering wastewater treatment plants. At the wastewater treatment plant, wastewater goes through physical, chemical and biological processes that clean it and remove the solids. If necessary, the solids are then treated with lime to raise the pH level to eliminate odors. The wastewater treatment processes sanitize wastewater solids to control pathogens (disease-causing organisms, such as certain bacteria, viruses and parasites) and other organisms capable of transporting disease. 

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