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Thickening Characteristics of Activated Sludge by Air Flotation Process  

Park, Chanhyuk (한국과학기술원 수질환경 및 복원연구센터)
Hong, Seok-won (한국과학기술원 수질환경 및 복원연구센터)
Maeng, Juwon (한국과학기술원 수질환경 및 복원연구센터)
Lee, Sanghyup (한국과학기술원 수질환경 및 복원연구센터)
Choi, Yong-su (한국과학기술원 수질환경 및 복원연구센터)
Moon, Seong-yong (엔바로테크(주) 부설연구소)
Publication Information
Journal of Korean Society of Water and Wastewater / v.20, no.5, 2006 , pp. 747-753 More about this Journal
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 12,000mgSS/L and thickened sludge concentration varied from 6,400 to 28,100mgSS/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 5,000mgSS/L and the thickened concentration was over 20,000mgSS/L. At this time, SS concentration in the clarified liquid was ranged from 5 to 10mg/L.
Keywords
Air flotation; A/S ratio; Air pressure; Rotation time; Initial MLSS concentration; Surface loading;
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