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

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 m3,and polyvinylidene fluoride membrane with pore diameter of 0.09 to 0.12 μm and total area of 85.2 m2 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.