Impact of electrical stimulation intensity on methane production and fouling in anaerobic membrane bioreactors
To mitigate membrane fouling in anaerobic membrane bioreactors(AnMBR)during sewage resource recovery,this study investigated the impact of various electrical stimulation intensities on methane production efficiency and membrane fouling.The results reveal that a suitable intensity of electrical stimulation(1.0 V·cm-1)could lead to high COD removal with an average removal rate of(85.9±5.9)%.In comparison with AnMBR,electrical stimulation intensities of 0 to 2.0 V·cm-1 in EAnMBR could extend the membrane fouling cycle by 13.8%~24.0%,increase methane production by 15.9%~43.8%,decrease EPS content by 3.5%~27.1%,and decrease SMP content by 24.3%~52.0%.The application of electrical stimulation promoted the degradation of acetate-dominant volatile fatty acids.Hydrogenotrophic methanogens,Methanobrevibacter,presented a greater adaptability to the electrical stimulation environment than acetate-utilizing methanogens.Conversely,the relative abundance of extracellular polymeric substances-producing Streptococcus decreased with the increase of electrical stimulation intensity.Based on the synergistic effects of methane resource recovery and the extension of membrane fouling cycles,2.0 V·cm-1 was considered as a favorable intensity of electrical stimulation.The results can provide valuable insights for AnMBR coupled with electro-assistive processes.