The synergistic strategy and microbial ecology of the anaerobic co-digestion of food waste under the regulation of domestic garbage classification in China

Abstract

With the implementation of new domestic garbage classification policy in China, attention is growing to improve the treatment efficiency of municipal 'wet' waste. Combing with the new regulation, the synergistic strategy and the microbial ecology of the anaerobic co-digestion (AcoD) of cooked food waste (CFW), uncooked food waste (UCFW) and rice straw (RS) were analyzed in current study. Results showed that the maximum cumulative methane yield (CMY) and synergic index were obtained when CFW and UCFW were mixed at the ratio of 1:1 (based on volatile solid content). The highest CMY 452.94 ± 0.99 mL/g-VS was obtained when the ratio of CFW, UCFW and RS was 0.81:0.09:0.10, which was 16.29%, 36.20% and 121.84% higher than their mono-digestion, respectively. The AcoD promoted the methane potential by prolonging the release time of organic matter and slowing down the hydrolysis rate. Furthermore, the AcoD increased the species diversification and relative abundance of fermentation bacteria in digesters, and Methanosaeta predominated the methanogen communities. This study demonstrated a clean and sustainable AcoD strategy for safe disposal of urban food waste and revealed the variation of microbial community, which can provide a base for efficient bioenergy recovery from urban domestic garbage.

Keywords: Anaerobic co-digestion; Food waste; Methane potential; Microbial community; Synergistic effect.