倒置A2/O-MBR处理城市污水的中试研究

针对城市生活污水,研究了两点进水倒置A2/O-MBR系统对COD、NH4+-N、TN、TP、出水SS、跨膜压差(TMP)的影响.结果表明,该系统对COD、NH4+-N具有较高的去除率,出水符合GB 18918-2002中一级A标准;当混合液回流比为200%时,系统出水TN浓度小于15 mg.L-1;正常排泥后,系统对TP的去除率达90%左右;在膜丝未大量断裂前,系统出水SS小于10mg.L-1;随着系统的运行,TMP逐渐增大,不正确的曝气方式会导致TMP迅速增加.膜截留对COD、TP、SS有直接去除作用,由于膜滤出水中没有固体损失,可以精确控制污泥龄,有利于世代周期较长的硝化菌和反硝化菌在反应器中生长;当污泥浓度增加到6 500 mg.L-1左右,进水量增加0.5倍对出水水质影响很小.

Treatment of Municipal Wastewater Using the Combined Reversed A2/O-MBR Process

For the treatment of municipal wastewater, the effects of the reversed A²/O-MBR system on COD, NH₄⁺-N, TN, TP, SS and transmembrane pressure(TMP)were investigated through two-point feeding. The results indicated that the removal efficiencies for COD and NH₄⁺-N were high in the system, the effluent met the requirements of the Class A in first grade discharge standard of GB 18918-2002. The effluent TN was <15 mg·L^-1 when the reflux ratio of nitrification was 200%, whereas the average TP removal rate was 90% after the excessive sludge was removed. The effluent SS was <10 mg·L^-1 before the large-scale breakage of membrane. The TMP increased gradually with the operation of the system, if the way of aeration was not correct, the TMP would increase quickly. Efficient separation by the membrane contributed to the removal of COD, TP and SS. Because there was no sludge washout in the system, SRT could be properly controlled, it was good for the ammonia-oxidizing bacteria and denitrifying bacteria which both have long life-cycle. Even if the inflow was increased to 1.5 fold, the effluent quality was good when the sludge concentration was increased to 6500 mg·L^-1.