Pilot-scale two-phase anaerobic digestion of deoiled food waste and waste activated sludge: Effects of mixing ratios and functional analysis.

Anaerobic co-digestion of deoiled food waste (dFW) and waste activated sludge (WAS) can address the challenges derived from mono-digestion of FW. In the present study, a pilot-scale methanogenic bioreactor of a two-phase anaerobic digestion system was developed to explore the impact of dFW/WAS volatile solids ratios on the overall performance, microbial community, and metabolic pathways. Besides, the tech-economic of the system was analyzed. The results showed that the degradation efficiency of soluble chemical oxygen demand (SCOD) was more than 84.90% for all the dFW/WAS ratios (v/v) (1:0, 39:1, 29:1, 19:1 and 9:1). Moreover, the dominant genus of bacteria and archaea with different ratios were Lactobacillus (66.84-98.44%) and Methanosaeta (53.66-80.09%), respectively. Co-digestion of dFW and WAS (29: 1 in v/v ratios) obtained the highest yield of methane (0.41 L CH4/Ladded) with approximately 90% of SCOD being removed. In the pilot-scale experiment, the co-digestion of FW and WAS makes positive contribution to reusing solid waste for improving solid management.