공기부상법을 이용한 활성슬러지의 부상분리 특성

Abstract

Air flotation is a solid-liquid separation process that utilizes up-flow microbubbles to thicken activated sludge and enhance clarification efficiency. Continuous air flotation experiments were performed to investigate the effect of operation parameters such as initial MLSS (mixed liquor suspended solid) concentration, air pressure, surface loading rate, air to solid (A/S) ratio, and flotation time on thickening efficiency. An initial activated sludge concentration ranged from 3,000 to 12,000 mgSS/L and thickened sludge concentration varied from 6,400 to 28,100 mgSS/L. The result showed that the thickening efficiency was mainly dependent on surface loading rate, A/S ratio, and flotation time. The pressure did not affect the thickening efficiency when it kept in the range of 1.6 to 1.8 bar. Experimental results showed that the thickening efficiency of activated sludge was increased only when the feed sludge concentration exceeded 5,000 mgSS/L and the thickened concentration was over 20,000 mgSS/L. At this time, SS concentration in the clarified liquid was ranged from 5 to 10 mg/L.