SPEED-CONTROLLED WASTE TREATMENT AERATORS CONSERVE HORSEPOWER.

At most activated sludge plants the aeration system is the major energy consumer. Recently, at least one company has been doing work using a completely different way of pacing power to oxygen requirements. The system utilizes adjustable frequency drives (AFD's), mechanical low speed aerators, and a dissolved oxygen control system. The AFD has been successfully used for almost two decades in the synthetic fiber, machine tool and textile industries, and sewage pump stations and wastewater plants to control pumps.