Activated Sludge Process

A process used as secondary treatment to remove soluble, colloidal, and particulate (suspended) organic substances. It consists of a reactor receiving a mixture of primary treatment effluent and recycled activated sludge, which is aerated and agitated, promoting the formation of microbially-active, flocculent settleable solids. Upon sedimentation, part of this activated sludge is recycled back into the reactor.