Air flotation clarifier

Abstract

A clarifier is provided with an elongated settling tank having an inlet at one end, an outlet at the opposite end, a generator producing air saturated liquid released near the inlet end of the tank to float lighter sludge to the top of the tank, suction heads removing settled out heavier sludge from the bottom of the tank, skimmers pushing scum or foam floating on top of the liquid in the tank to the overflow outlet near the inlet end of the tank, a travelling bridge moving the suction heads along the length of the tank, elongated outlets for clarified liquid projecting into the tank from the discharge end thereof, and outlets at different levels for discharge of clarified effluent and recirculating effluent. The recirculating effluent is pumped to a mixing device to be saturated with air and the air saturated effluent is discharged back into the inlet end of the tank. A pressurized tank for air saturated effluent receives the admixed air and effluent from the mixing device into the bottom thereof and air from the top of the tank is compressed by a liquid ring compressor to charge the mixing device. The dissolved air flotation takes place at the inlet end of the tank and the floating froth or scum is pushed into the top of the collector trough extending across the inlet end of the tank. A control panel on the unit monitors all of the operations and the entire unit is portable to be easily placed alongside any industrial equipment having liquid to be clarified.