Investigating the role of different materials supplementation in anaerobic digestion of kitchen waste: Performance and microbial community dynamics

Anaerobic digestion (AD) is a promising strategy to achieve both carbon emission reduction and sustainable development. In this work, the performance and microbial community dynamics were investigated in an anaerobic digestion system using four different type of materials. The results obtained indicated that, in the presence of bentonite with the properties of high grease adsorption and alkaline, the improved performances involved in biogas production rate (996.0 mL/g-VSFW) and organic removal efficiencies (84.38%) were higher than that in the presence of biochar. However, activated carbon and zero-valent iron inhibited kitchen waste AD's biogas production rate. Microbial community analysis revealed that the hydrogenotrophic mathanogenesis significantly increased when the additive was fed with kitchen waste digester. Bentonite increased the compo-sition and diversity of archaea and bacteria and enriched Methanolinea and Bathyarchaeia which in turn improved AD performance. Biochar enriched Lentimicrobium capable of electron transfer to conductive material. Together with the increased abundance of Methanobacterium that could proceed direct interspecies electron transfer (DIET), AD was likely improved due to the processing of DIET with adding biochar. In this way, this study was expected to obtain a research basis for evaluating the influence of exogenous additives on kitchen waste AD.