Research On The Biological Aerated Filter /Conventional / Membrane Combined Process Water Treatment Technology

In the situation of water shortage and environmental deterioration, some water plants in Southwest China have to choose micro polluted water as the source of drinking water. Facing the increasingly serious problem of water pollution,it has been difficult for conventional treatment process to ensure the safety and stability of drinking water. Biological aerated filter(BAF) and the membrane separation technology(especially the UF) have become an important supplement for conventional treatment process. In this study, the Zhuxi River in Beibei District of Chongqing was used as the raw water to research on water purification technology of the biological aerated filter /conventional / membrane combined process.Specific to the micro-polluted raw water,the experiment of compound inoculation start-up was used to biological aerated filter. The result showed that BAF could be started quickly,and compound inoculation start-up was completed after13 days in the southern summer. The ammonia nitrogen removal efficiency of raw water was more than 60%,CODMn removal efficiency more than 15%.During the research on utra filtration membrane of critical flux, the result of critical flux measurement test showed that the critical flux located between 32.95 L/(m2.h)~ 35.93 L/(m2.h). And then ultrafiltration system was operated under subcritical flux 32.95 L/(m2.h) and transmembrane pressure 0.040 Mpa, to study water purification performance and membrane fouling of the ultrafiltration combined process?In the wet season, the effluent turbidity, NH3-N, CODMn, Fe, Mn of coagulation sedimentation-ultrafiltration process all achieved the "drinking water health standards"(GB5749-2006), and the effluent turbidity, Fe, Mn achieved the “Drinking Water Quality Standards”(CJ94-2005). The effluent turbidity, NH3-N, CODMn, Fe and Mn of coagulation sedimentation-filtration process all achieved the "drinking water health standards"(GB5749-2006), however the effluent turbidity could not achieve the "drinking water health standards"(GB5749-2006). It was higher than 0.5 NTU.In the dry season, in the raw water artificial add ammonium experiment, when the raw water ammonia was between 0.986 mg/L~2.068mg/L. After 53 hours flow rate was regulated to 335L/h,and BAF effluent ammonia nitrogen was under 0.5mg/L. According to the experimental result, the flow rate of BAF in the following combination process was 335L/h.In the dry season,in the raw water artificial add ammonium experiment between temperatures 8.6 ? and 11.8 ?, the experimental results showed that the removal efficiency of turbidity, NH3-N, CODMn, Fe and Mn in BAF system had good rules. But the removal effect of UV254 is not good. When the UV254 contents was high, BAF could not declined it to a lower level.In the dry season, under stable operation conditions the effluent turbidity, NH3-N, CODMn, Fe and Mn of both BAF-ultrafiltration process and BAF-rapid filtration process achieved the "drinking water health standards"(GB5749-2006). BAF-ultrafiltration there were advantageous aspects of the removal of turbidity and total colony. It could significantly improve the biological security of drinking water.Comparing the permeability of UF membrane by different chemical cleaning and components desorbed from the fouled membrane by different chemical cleaning, it could be concluded that both metals and organic matter should be responsible for membrane fouling.