BALTIMORE, MD (February 12, 2002) – The Hagerstown Wastewater Treatment Plant (WWTP) has begun disinfection of sewage today, which has been discharged in a partially treated state for several days into Antietam Creek in Washington County. The installation of chlorination and dechlorinization processes allowed the plant to resume disinfection. This is a temporary disinfection measure until the normal ozone disinfection process can be reactivated.
The discharge outfall is approximately 24 miles from the Potomac River. The discharge, which has flowing at up to 5.7 million gallons per day, began Saturday after chemicals from an unknown source entered the plant and destroyed the bacteria that helps to breakdown the sewage.
MDE, working with the City of Hagerstown, is aggressively investigating the cause of the incident and will take prompt and appropriate enforcement action.
In addition, MDE has been closely monitoring water quality by collecting samples in Antietam Creek in coordination and communication with the water supply systems with intakes downstream from the plant. Although there have been no visible impacts noted on aquatic life, people are cautioned to avoid water contact in Antietam Creek until further notice due to the potential for health impacts from the raw sewage.
The MDE has been working with water systems downstream, the Metropolitan Washington Council of Governments and the Interstate Commission of the Potomac River Basin (ICPRB) to make sure that all drinking water systems that draw water on both sides of the Potomac are kept apprised of the Department’s efforts and the latest data. These water systems are the Brunswick and the Frederick New Design – both in Frederick County, Maryland; Leesburg in Louden County, Virginia; the Fairfax County intake in Virginia; the Washington Suburban Sanitary Commission and Rockville intakes – both in Montgomery County, Maryland, and finally the Washington Aquaduct Division in Washington DC.
Since these system intakes are many miles downstream from the Hagerstown plant and it will take the discharge almost a week to reach the Washington Metropolitan area, the natural flow in these waterways will dilute the sewage. The harmful bacteria in the waste is not expected to survive under stream conditions and about 90% will die off before reaching the downstream water intakes. Local water treatment plants will be conducting additional monitoring and their advanced water treatment capabilities will enable any residual bacteria to be removed.
Chemicals detected in the sewage plant that may have been the cause of the problem – ethylbenzene, toluene and xylene -- have high evaporation rates and are expected to quickly dissipate once exposed to the natural environment.