AWWA INF52177

The Washington Aqueduct Division (the Aqueduct) of the U.S. Army Corps of Engineers was established in 1853 to provide a reliable and abundant water supply to the City of Washington, D.C. The Washington Aqueduct system serves three wholesale customers: the District of Columbia Water and Sewer Authority, Arlington County, and the City of Falls Church, Virginia. In 1994, the Aqueduct conducted an analysis of upcoming water treatment regulations and identified several modernization needs at two water treatment plants; the Dalecarlia and McMillan plants. An Ozone Feasibility Study was conducted to evaluate ozone's effectiveness in meeting final Enhanced Surface Water Treatment Rule and proposed Stage 2 Disinfectants/Disinfection Byproducts Rule requirements at the two plants. This paper reports the results of the study which evaluated the facility and operational modifications required to accommodate the use of ozone for primary disinfection at the Dalecarlia and McMillan water treatment plants. Includes figures.