Impact of incineration slag co-disposed with municipal solid waste on methane production and methanogens ecology in landfills

Co-landfill of incineration slag and municipal solid waste (MSW) is a main method for disposal of slag, and it has the potential of promoting methane (CH4) production and accelerating landfill stabilization. Four simulated MSW landfill columns loaded with different amount of slag (A, 0%; B, 5%; C, 10%; D, 20%) were established, and the CH4 production characteristics and methanogenic mechanisms were investigated. The maximum CH4 concentration in columns A, B, C and D was 10.8%, 23.3%, 36.3% and 34.3%, respectively. Leachate pH and refuse pH were positively correlated with CH4 concentration. Methanosarcina was the dominant genus with abundance of 35.1%similar to 75.2% and it was positively correlated with CH4 concentration. CO2-reducing and acetoclastic methanogenesis were the main types of methanogenesis pathway, and the methanogenesis functional abundance increased with slag proportion during stable methanogenesis process. This research can help understanding the impact of slag on CH4 production characteristics and microbiological mechanisms in landfills.