Patent ID: 6277273
Filing Date: 2001-08-21
Classification: B01D

Abstract:
A floatable decanter for removing supernatant liquid from a sewage treatment tank in which a period of agitation or aeration is followed by quiescent period during which scum usually forms at the surface at the liquid and sludge particles settle toward the bottom of the tank, comprising:a decanter body,at least one fixed float in the decanter body, sufficient to float the decanter even when substantially filled with liquid,an internal liquid sump in the decanter body,a liquid entry port in the decanter body, positioned to receive supernatant liquid into the decanter body and into the sump,a liquid outlet in the sump of the decanter, and conduit means for removing liquid flowing into the liquid outlet,at least one weir positioned between the liquid entry port and the liquid outlet, over which inflowing liquid flows and accelerates to reach the liquid outlet,a sludge barrier having open and closed positions effective to admit supernatant liquid through the liquid entry port when opened and to close the liquid entry port when closed, with means for opening the sludge barrier when liquid is being withdrawn out of the sump through the liquid withdrawal conduit, anda scum barrier on the decanter body, positioned to be adjacent to the surface of liquid in the tank and to prevent scum at or near the surface of the liquid in the tank from entering the liquid entry port.