activated-sludge process

activated-sludge process

[′ak·tə‚vād·əd ‚sləj ′prä‚səs] (civil engineering) A sewage treatment process in which the sludge in the secondary stage is put into aeration tanks to facilitate aerobic decomposition by microorganisms; the sludge and supernatant liquor are separated in a settling tank; the supernatant liquor or effluent is further treated by chlorination or oxidation.