A two-stage strategy combining vermicomposting and membrane-covered aerobic composting to achieve value-added recycling of kitchen waste solid residues

Kitchen waste solid residues (KWSR) are secondary organic solid wastes generated from kitchen waste (KW) after oil and slurry separation. In this study, two recycling methods for KWSR were investigated: direct membrane-covered aerobic composting (T1) and a two-stage method combining vermicomposting with membrane-covered aerobic composting (T2). Compared with T1, T2 had a faster increase in pile temperature, a shorter thermal stage, lower greenhouse gas emissions and higher NH₃ emissions. The vermicomposting promoted the formation of humus and shortened the maturation time during aerobic composting, resulting in a shorter treatment period for T2 (18 d) than for T1 (21 d). The initial bacterial communities of T1 and T2 were significantly different, but they became similar as composting progressed. The economic feasibility analysis showed that 1000 kg of KWSR generated a profit of 285 CNY using the T2 method, which was higher than that of T1 (36 CNY). The outcomes of the present study provide an improved strategy for the management of KWSR.