Research On Performance Of The Polishing Treatment Of Micro-polluted Water With Ultrasound-PAC-Membrane System

The pollution of water resources and more stringent purified drinking water standards have urged more researchers to develop new water treatment technology. Ultrasound has more advantages on the degradation of difficult biodegradation organism. Micro-filter(MF) has been studied widely for removing turbidity,microorganisms and low cost of running. This thesis combined Ultrasound, Powered Activated Carbon(PAC) and MF system to treat micro-polluted water. We hope that the effluent will meet the purified drinking water standard. At the same time, we studied on the performance of PAC-MF system and also studied the changes of bacteria and organic matters under the ultrasonic irradiation.The result of research shows that Ultrasonic irradiation will lead to the increase of UV254 and CODMN. The total power is higher, the increase is more. The removal effect of total number of bacteria is evident. After 60 min of ultrasonic irradiation, more than 50% of bacteria was inactivated,and the kinetic equation of bacteria removal is conformed to the first-order reaction.It also shows that CODMN and UV254 in raw water were removed rapidly and effectively by PAC absorption. The absorption meets the Freundlich absorption isotherm. In this study, we also can see that the removal efficiency of turbidity, bacteria and UV254 of PAC-MF system are similar in that of Ultrasonic-PAC-MF system. The turbidity of effluent is less than 0.5 NTU and meets the purified drinking water standard. At the beginning, almost 100% of bacteria and UV254 were removed, and then the concentration of UV254 in effluent was increased gradually. The removal effect of CODMN is different in two systems and PAC-MF system is better than another one. Under the same condition of adding 45g PAC to the reactor, there are twelve days in which the concentration of CODMN in effluent of PAC-MF system can meet the purified drinking water standards, while only eight days in another system. NH3-N removal rates also enhanced gradually in two systems with the runtime prolonged, but it caused the accumulation of NO2-N.At last we compared the treatment efficiency of PAC-MF system running at three different HRT. It shows that more organics was absorbed by per unit weight of PAC when the system is running at the lowest HRT. We suggest that the best running mode of PAC-MF system is lower HRT and higher initial concentration of PAC.