Patent ID: 6325933
Filing Date: 2001-12-04
Classification: C02F,Y02W

Abstract:
A process for biological purification of waste water comprising the steps of:(a) providing a mixture of non-treated waste water and sludge and continuously supplying said mixture into an inlet end of an aerobic treatment zone which has an inlet end and an outlet end,(b) aerating and stirring said mixture in said aerobic treatment zone so as to provide a water-rich fraction and a sludge-rich fraction as said mixture moves toward said outlet end,(c) passing said water-rich fraction from said aerobic treatment zone to a clarification zone wherein said water-rich fraction is separated into a water fraction and a sludge fraction,(d) recirculating a portion of said sludge fraction from step (c) to form the mixture in step (a),(e) recovering said water fraction from step (c), and(f) recirculating a portion of said sludge-rich fraction at said outlet end of said aerobic treatment zone to said inlet end.