The Research On The Treated Effect Of Submerged Membrane Bioreactor

Water treatment technology by Membrane Bioreactor (hereafter referred as MBR) is a high-efficient bio-chemical water treatment technology with combination of biological technology and membrane technology. MBR is a high efficient and practical technology for wastewater treatment, combining the traditional sludge process with the high efficient membrane separation technology. Due to membrane filtration, the organism are intercepted within the bioreactor. In the compact space, microbial degradation and isolation of pollutant are achieved simultaneously, and hydraulic retention time and sludge age are separated totally. There is a high sludge concentration in the bioreactor, with strong nitrification ability and high pollutant removal rate.Analysis the characteristics of Membrane Bioreactor, this thesis discusses the plasma modified membrane modules for the treated effects of domestic wastewater.It also studies hydraulic retention time on the impact of the reactor and the intermittent operation and the sludge concentration on membrane fouling. Finally, contaminated membrane reasons and cleaned membrane methods are also presented during cleaning membrane process. In addition, domestic wastewater treated effects between Membrane Bioreactor (MBR) and Membrane Bio-membrane Reactor (MBMR) are compared in this article. These experiments were done in order to find the best operational condition,so as to optimize the operation condition and reduce the cost. It mainly includes the following points:(1)Original membrane and modified membrane which were put in MBR are compared in terms of running effect in order to confirm the applicability of the plasma modified membrane in membrane fouling mitigation.In terms of treated effects of wastewater,action of modified membrane in MBR is better than original membrane.According to membrane fouling and capability, membrane flux of original membrane is better than that of modified membrane when they were put in MBR.Thus,the plasma modified membrane is not yet applicable in MBR process.(2)Polyvinylidene fluoride hollow fiber membrane could run steadily for a very long period between MBR and MBMR in order to confirm which one is the best.The results indicate that the treated effects and stability of MBMR are all better than that of MBR. Furthermore, MBMR excels MBR in operating conditions. Thus MBMR has the advantage of treated effects and operating conditions.But MBR is better than MBMR in terms of membrane fouling and capability. Therefore, the choice of Membrane Bio-membrane Reactor (MBMR) also bases on actual operating conditions. (3)The thesis studies treated effects in MBR are affected by HRT while the ratio of air and water is 20:1.The results show that the best levels about HRT is 6h.(4) The thesis studies membrane flux are affected by different suction and pause time. The results show that the best intermittent operation with suction time 5min and pause time 1min could be adopted.(5) The correlation has been studied between the sludge concentration and membrane fouling. The results indicate that the membrane flux declines as the sludge concentration increases. However,the composition of the sludge mixture is complicated and variational.Therfore,it needs studied further to prevent membrane fouling by improving the characteristics of the liquid.(6) The thesis studies the cleaning effect of different membrane cleaning methods. The results show that a single cleaning method can not achieve a good cleaning result, while methods combined physics and chemistry are the best way.