Ultra-filtration and Its Hybrid Processes for Tertiary Treatment of Sewage

Experiments of treating the effluent from a sewage secondary treatment plant by UF and UF plus coagulation or powdered activated carbon (PAC) were carried out. The results show UF removes turbidity completely, more than 99% bacteria and E coli and a certain amount of organic matters, ammonia nitrogen and manganese. Hybrid processes featuring UF preceded by coagulation or PAC enhance the removal of organics, and moreover, reduce UF membrane fouling, improving flux of membrane. According to the experimental study, it is concluded that a shortened filtration period and increased backwash frequency result in higher water yield per unit energy consumption with same amount of backwash water.