Location:

South of Hagerstown, in southern central Washington County, Md.

Constructed:

Built in 1936, MES began operating the plant in 1972

Design flow:

1.6 million gallons per day

Actual flow:

950,000 gallons per day

Process:

The facility uses an automatic bar screen and a flow equalization tank for controlling surges. From there it is pumped to a 4-stage Bardenpho carousel (BNR) then flows by gravity to the clarifiers.

Gas chlorination is the method used for disinfection and sulfur dioxide gas for dechlorination. Effluent dissolved oxygen levels are maintained by the use of a cascade post aeration system. Sludge treatment consists of gravity thickening then de-watering by a belt filter press.

The sludge cake is stabilized by the addition of lime, then conveyed to the sludge storage building for storage and/or disposal. The lime stabilized sludge can be land-filled or land applied.