Record Display for the EPA National Library Catalog


OLS Field Name OLS Field Data
Main Title Density Currents in Activated Sludge Secondary Clarifiers.
Author Bender, J. H. ;
CORP Author Environmental Protection Agency, Cincinnati, OH. Water Engineering Research Lab.
Year Published 1988
Report Number EPA/600/2-88/006;
Stock Number PB88-155312
Additional Subjects Clarification ; Activated sludge process ; Sewage treatment ; Density(Mass/volume) ; Mixing ; Currents ; Velocity ; Solids ; Settling ; Weirs ; Quality control ; Reviews ; Intake systems ; Baffles ;
Library Call Number Additional Info Location Last
NTIS  PB88-155312 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. 06/21/1988
Collation 73p
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.