Enhanced Methane Production Of Food Waste Via Conductive Materials In Two-phase Anaerobic Digestion: Substance Conversion And Microbial Communities

Abstract The treatment and resource utilization of solid waste were the important problems that should be solved instantly. Food waste was an organic solid waste available for the production of sustainable energy. This study investigated the effects of activated carbon (AC), zero-valent iron (ZVI), and magnetite (Mt) on two-phase anaerobic digestion performance of food waste. The results suggested that adding ZVI in the acidification phase improved the concentration of volatile fatty acid by 46.4%-47.9% than that of the control group, which provided a better initial condition for the methanation phase and decreased the delay time of methane production. In the methanation phase, adding AC and Mt increased the methane production by 28.1%-68.4% compared with the control group. The analysis of microbial community structure indicated that adding ZVI improved the relative abundance of hydrolytic acidifying bacteria, including Corvnebacteriun , Fastidiosipila , Gallicola , and Syntrophaceticus in the acidification phase. Moreover, the addition of conductive materials promoted the dominant relative abundance of Methanobacterium , Methanoculleus , and Methanosarcina to stimulate the multiple methanogenic pathways of hydrogen and acetic acid.