You are here:
DENSITY CURRENTS IN ACTIVATED SLUDGE SECONDARY CLARIFIERS
Citation:
Bender, J. DENSITY CURRENTS IN ACTIVATED SLUDGE SECONDARY CLARIFIERS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/2-88/006 (NTIS PB88155312).
Description:
Density currents form in activated sludge secondary clarifiers because the mixed liquor has a density greater than the treated wastewater in the clarifier. This causes the mixed liquor to plunge to the bottom of the clarifier establishing relatively high velocity currents within the clarifier that can transport settled solids out of the clarifier in the effluent. The report reviews the literature relative to density current formation, methods available for control and their effectiveness in minimizing the impact of density current on activated sludge secondary clarifier effluent quality. Control procedures reviewed include inlet structures, weir length and placement and in-tank baffles.