Research On The Performance And Fouling Characteristics Of A Membrane Bioelectrochemical Reactor

Due to their unique advantages like high quality effluent and suitable for wastewater treatment plant upgrades, Membrane bioreactors (MBR) are becoming increasingly popular. However, membrane fouling increases the energy consumption and membrane replacement cost, and it has become a key factor, which limits its development and wide spread. Microbial fuel cells (MFC) are promising for application, for they can recover electricity from wastewater.In this study, a new membrane bioelectrochemical reactor (MBER) has been established, which integrated a two-chamber MFC with a membrane reactor. The MBER can not only recover the energy from the wastewater, but also take full advantages of the electric field inside the membrane to transform or change the characteristics of the sludge, which will lead to membrane fouling mitigation. In this study,1) the stability of the MBER,2) the performance of wastewater treatment efficiency, sludge characteristics, and membrane fouling,3) and the mechanism of membrane fouling mitigation of the MBER were analyzed.The electricity performance of the MBER was recorded by a paperless recorder. The average output power reached867.8mW/m3, when the external resistance was50Ω. The MBER maintained a good and stable performance throughout the operation time, for that the MFC kept a low resistance of about160Ω, and both biological anode and cathode showed a delightful catalysis.Compared with the control system, the microorganisms in the MBER had a much higher activity, and the removal efficiencies of chemical oxygen demand (COD) and NH4+-N of the MBER reached94.18±1.24%and96.77±1.80%, respectively. The membrane fouling period of the MBER has extended from20days of the control system to37days. The MBER showed good performance.Finally, the mechanism of the fouling mitigation of the MBER was analyzed. When compared with the control system, the soluble microbial products (SMP) and loose-extracellular polymeric substances (LB-EPS) decreased14.1%and24.0%, respectively, and the hydrophobicity of the sludge reduced46%. The filamentous bacteria had been restrained, and the ratio between the extended filamentous bacteria and the floc area (E/F) is52%lower than that of the control system. The value of the sludge’s roundness (R), form factor (FF) and aspect ratio (AR) of the MBER were all more close to1, demonstrating the spheroidization and homogenization of sludge flocs, which could hinder the accumulation of the sludge on the membrane’s surface.The MBER achieved long-term stable performance, and can obtain high efficiency of wastewater treatment and effective mitigation of membrane fouling simultaneously. It has significant prospects for development.