| Anaerobic Membrane Bio-Reactor Anaerobic (AnMBR) is a new type of wastewater treatment technology which combines membrane separation technology and anaerobic biological treatment. It has been a research focus.However, compared to Aerobic MBR,AnMBR has not been applied in large scale, and membrane fouling is the main obstacle which hinder the wide application of AnMBR in wastewater treatment field. Due to the reason that high concentration of sludge and aeration restriction in anaerobic treatment process, the membrane fouling of AnMBR is more serious than aerobic MBR. Therefore, it is in urgent need to address the biofouling issue in AnMBR for future application. This study brought the electric field into AnMBR system to couple microbial electrolysis cell(MEC) with AnMBR and built a new type of MEC-AnMBR reactor. We explored the degradation effect of organic pollutants, membrane fouling and microbial community succession of this reactor under different condition of long running in order to ascertain the relationship among applied voltage, microorganism and membrane fouling,thereby providing theoretical basis and technical support for the engineering application of the MEC-AnMBR wastewater treatment process. The main results were concluded as follow:1. Study on the efficiency of the novel MEC-AnMBR reactor:a new type of MEC-AnMBR reactor was built and launched, we explored the impact of applied voltage, influent pH, volume load on its sewage treatment efficiency. The results showed that 0.6V was the most suitable applied voltage for the removal of organic pollutants;under the condition of 0.6V,it was appropriate to kept a neutral acid-base property for influent of MEC-AnMBR reactor,and the alkaline resistance of the reactor was better than acid resistance; under the voltage of 0.6 V, it can be seen that volume load could play a significant influence on organic matter removal effect of the reactor.If the reactor should be on practical applications,we need to select an appropriate range of volume load.2. Study on the membrane fouling control of the novel MEC-AnMBR reactor:we explored the change of membrane fouling under the voltage of OV,0.4V,0.6V,0.8V and 1.0V respectively, and investigated the reason for the mitigation of membrane fouling from aspects such as sludge concentration, sludge particle size distribution, sludge zeta potential, sludge viscosity, EPS and SMP. The results showed that the applied electric field does have some relief impact on the membrane fouling and the relief impact on membrane fouling by electric field mainly displayed in the later stage of membrane fouling; the mitigation of membrane fouling caused by applied electric field was implementated through increasing absolute value of sludge zeta potential,decreasing sludge viscosity and reducing EPS content.The reduction of EPSp/EPSc ratio was likely to be the direct reason of the increase of absolute value of sludge zeta potential and decrease of sludge viscosity.In addition, the relevance among applied voltage, content and composition of SMP as well as mitigation of membrane fouling could not be determined by this experiment.3. Study on the microbial community of the novel MEC-AnMBR reactor:the change of microorganism community structure of sludge in the reactor was explored by high-throughput sequencing technology,and we studied the impact of applied voltage on the microorganism community structure of archaea and bacteria. The research showed that applied electric field increased the richness and diversity of archaea community structure in the reactor,the Methanosaeta and Methanoregula could use electron from electrode more effectively or better adapted to the environmental conditions under the electrochemical action than Methanosarcina;applied voltage also increased the richness and diversity of bacteria community structure in the reactor,the existence of applied electric field could promote the growth of electricigens with extracellular electron transfering ability. |
PDF Full Text Request