72 / 2023-06-03 14:28:14

Linking performance to dynamic migration of biofilm ecosystem reveals the role of voltage in the start-up of hybrid microbial electrolysis cell-anaerobic digestion

Anaerobic digestion,Waste activated sludge,Electrode biofilm,Methane production

Hybrid microbial electrolysis cells-anaerobic digestion (MEC-AD) has become one of the effective ways to accelerate methane production of waste activated sludge. There is still inadequate, however, on the initial biofilm formation and changes of performance. In this study, the MEC-AD performance and electrode biofilms formation of startup feeding with rawwaste activated sludge (rWAS) and heat pretreated waste activated sludge (hWAS) was evaluated at different applied voltages. The results showed that methane productivity of rWAS and methane yield of hWAS at 0.8 V was 4.1 times and 3.8 times than that of 0V, respectively. Microbial community analysis revealed that hydrogenotrophic methanogenesis (e.g. Methanobacterium) and syntrophic bacteria (e.g. Syntrophomonas) in cathode biofilm and exoelectrogens (e.g. Geobacter) in anode biofilm was the core functional microorganisms in MEC-AD at 0.8V, which syntrophism and interspecies interaction resulted in higher methane productivity and acetogenesis. These findings provide academic supports for core functional microorganisms in MEC-AD.