Patent ID: 7344643
Filing Date: 2008-03-18
Classification: C02F,Y02W

Abstract:
1. A method for treating wastewater comprising: combining the wastewater with activated sludge in an activated sludge tank to form a mixed liquor; transferring the mixed liquor to a solid-liquid separator to separate the mixed liquor into a clear effluent and a sludge stream; transferring at least a portion of the sludge stream to a bioreactor; converting phosphorus in the sludge stream into soluble phosphates in the bioreactor; transferring at least a portion of the sludge stream from the bioreactor to a sidestream reactor; adding a source of multivalent metal ions to the sludge stream in the sidestream reactor to precipitate phosphate solids; separating and removing the phosphate solids from the sludge stream; and returning the sludge stream to the activated sludge tank for further treatment with the mixed liquor.