Patent ID: 6290849
Filing Date: 2001-09-18
Classification: C02F,Y10S

Abstract:
A method for biological purification of waste water by an activated sludge method, wherein the waste water is continuously passed through at least two treatment zones in which the waste water is successively subjected to nitrification and denitrification, and an optional clarification zone for dividing the treated waste water into a water fraction and a sludge fraction, using an apparatus comprising four treatment zones I, II, III, IV, wherein alternating anoxic and aerobic conditions and optionally sedimentation are established, said treatment zones being arranged around a central supply zone for waste water to be purified wherein only two treatment zones I, IV are provided with means for discharging treated water, untreated waste water from the central supply zone is alternatingly passed into a first of the four treatment zones I, II, III, IV, operated under anoxic conditions, and following an optional treatment in one or two additional treatment zones II and/or III, is passed into a last treatment zone I, IV from which treated waste water is discharged.