Experimental Study On Membrane Submerged Membrane Bioreactor Treating Municipal Wastewater

Our country is one of the countries which are poor in fresh water. The shortage of water has seriously limited the development of economics and improving of people's living standard, hence, the treatment and reclaiming of municipal Wastewater is one of the feasible methods to solve the fresh water crisis. Submerged Membrane Bioreactor (MBR) is a new and effective Wastewater treatment technology which combines biodegradation and separating of membrane and have many better advantages than other traditional secondary treatment processes. The experiment used MBR to remove the COD , nitrogen and phosphorus in municipal Wastewater, and the aim is to do some effective research in reuse of municipal Wastewater.In the experiment, the author has done some primary researches on municipal Wastewater treatment by MBR in different conditions. The test result showed that the average removal efficiency of COD was about 93～95%, which had not something with varies of DO and HRT. In the condition of lower DO, the removal efficiencies of NH₄⁺-N ,TN and TP can achieve 77.4%, 73.6% and 96.4% respectively; in the conditions of higher DO, NH₄⁺ - N can be removed 98.7%, whereas, the removal efficiencies of TN and TP were 38.5% and 74.3% only. In spit of these, SS and turbidity also were well removed by MBR.The trial also proved that membrane can greatly increased the process ability on the influent load because of the efficient separating function of MBR. With the lower DO, the process had a good efficiency for short-cut nitrification and had a good removal efficiency of NH₄⁺ -N; on the other hand, the MBR had aerobic and anaerobic surrounding which fitted nitrification and denitrification, so a good removal efficiency of TN can be got by MBR and a simultaneous phosphorous removal can be got by the function of denitrifying accumulating phosphorus organisms. With the higher DO, the nitrification was enhanced and denitrification was limited because the aerobic surroundings were dominant in MBR, so the good removal efficiency of NH₄⁺ - N was got and the TN and TP were not well removed.The trial also did some simple researches on the relation between temperature and removing of nitrogen and phosphorus. The result showed that the good efficiency of nitrogen and phosphorus removing were got in higher temperature by which the activity of microbial organisms could be improved.MBR is a new technology of Wastewater treatment which has some special advantages, and the effluent water by MBR has a stable and good quality, which can be used as many water resources.