The Research On Domestic Wastewater Treatment For Nutrient Removal Using New Type Of Biofilm-Membrane Bioreactor

A new MBR Process, in which the micro-filter membrane is coupled with biofilm reactor, was studied in pilot-scale experiment. This research focused on the nitrogen & phosphorus removal characteristics and other relevant impact factors. The removal of organic pollutants was included as well. In addition, Membrane fouling, how to control the membrane pollution, and refreshing were also discussed.The main process parameters such as organic loading, return ratio R, and interior return ratio r etc. were tested. The result shows that the organic loading of influent is the dominant factor for N & P removal. When the ratio of CODcr/TN>4, the removal of N is subject to the return ratio R, and less influenced by the inlet organic concentration. However, the removal of P has some relationships with that. The higher the CODcr/TN, the better the phosphorus removal. On the other hands, in the case of CODcr/TN<4, interior return ratio r is the main limited factor for phosphorus removal.Refer to some relevant data, the test shows that the biofilm reactor with floating carrier enhanced the conventional MBR, and is helpful for reducing fouling. The MSE indicated that membrane fouling mainly caused by the accumulated cakes.The recommended process parameters is: Membrane flux 10L/( m2.h) , HRT 8h, SRT 42d, 8min working and 2min intermission for pump. DO of anaerobic is zero, anoxic DO<0.2mg/L,arobic DO=0.5~1.2mg/L The interior return ratio r >150%, and 200% or 300% can be appropriate according to the quality of effluent for R.For the typical influent: TN<45mg/L, CODcr/TN>4,TP: 5~7mg/L, The stable optimum removal rate of CODcr, BOD5, NH3-N, TN, TP is as high as 90%, 98%, 95%, 77%, 84.9%, respectively.the effluent of CODcr, BOD5, NH3-N, TN, TP is 23mg/L, 2.6mg/L, 4.5mg/L, 13.6mg/L, 0.78mg/L, respectively. After disinfecting, the effluent quality can meet The reuse of urban recycling water-Water quality standard for scenic environment use. GBIT18920-2002. The reuse of urban recycling water-Water quality standard for urban miscellaneous water consumption. GB/T18921-2002.