PAC/MBR处理微污染地表水的中试研究

Pilot-scale Study on PAC/MBR for Treatment of Micro-polluted Surface Water

采用投加粉末活性炭(PAC)的膜生物反应器(MBR)复合工艺——PAC/MBR处理微污染地表水,考察了对浊度、CODMn和氨氮的去除效果。膜生物反应器的有效容积为4m3,采用聚偏氟乙烯平板膜,膜孔径为0.09～0.12μm,总膜面积为85.2m2;MBR的进水流量为1200L/h,一次性投加PAC为1g/L,气水比为5∶1;采用恒压操作、间歇抽吸方式出水,操作压力为0.1MPa,抽停比为8min/2min。中试结果表明,该工艺对沉淀池出水中浊度、CODMn和氨氮的平均去除率分别为98%、33%和53%,能抵抗水质和水温变化的冲击,有效保障出水水质。在PAC/MBR系统中,PAC吸附、生物降解和膜截留作用在去除不同分子质量有机物的过程中具有较好的互补性。投加PAC有助于在膜表面形成稳定的生物活性炭动态膜,保证了恒定的出水流量。

The combined process of powdered activated carbon and membrane bioreactor （PAC/ MBR） was applied for treatment of micro-polluted surface water, and the removal efficiencies of turbidity, CODMn and ammonia nitrogen were investigated. The effective volume of MBR is 4 m^3, and polyvinylidene fluoride membrane with pore diameter of 0.09 to 0.12 μm and total area of 85.2 m^2 was used. The operation conditions were the influent rate of 1 200 L/h, PAC of 1 g/L, air/water ratio of 5 ： 1, effluent mode with constant pressure and intermittent pumping, pressure of 0. 1 MPa and open/stop time ratio of 8 min/2 min. The results show that the average remoal rates of turbidity, CODMn and ammonia nitrogen in the effluent from sedimentation tank are 98% , 33% and 53% respectively. The combined process has strong resistance to change in water quality and water temperature, so as to guarantee highly qualified effluent. In PAC/MBR system, there is an excellent complementarity among PAC adsorption, biodegradation and membrane rejection for removing organic matters with different molecular weights. Adding PAC can facilitate the formation of a stable biological activated carbon dynamic membrane, which ensures the system to produce constant effluent flow.