Method for biological effluent treatment

Abstract

The invention relates to a method of biological treatment of wastewater by means of activated sludge, wherein the wastewater is introduced first into an acrated activated sludge tank (B tank) and then by turns into one of several sedimentation and recirculation tanks (SU tanks), which are permanently linked with said B tank and in which a separation of activated sludge and clear water occurs, and after separation activated sludge is returned to the B tank and clear waters is drawn off; several times a day, in the SU tanks an operating cycle proceeds comprising a stirring phase (R phase), a pre-settling phase (V phase) and a discharge phase (A phase). In the R phase the activated sludge is remixed with the water, in the V phase the activated sludge settles down and in the A phase clear water is drawn off (single basin technique). The cycles in the SU tanks are phase displaced to each other and the A phases are adjacent, so only in the A phases the SU tanks are flown through, an approximately constant water level is present; thus causing an outflow from the purification plant which corresponds to its inflow (throughflow principle). Before the R phase settled and thickened activated sludge is reintroduced from the SU tank into the B tank.

Dependencies are inferred from the claim text.