Abstract: The gas production process in sludge-municipal solid waste (MSW) mixture under different sludge addition conditions was studied through laboratory experiments, and a kinetic model of gas production process in the mixture degradation was established. Results show that the gas production process can be divided into three stages: adjustment stage, acceleration stage, and attenuation stage. With the increase in sludge amount, the cumulative gas production gradually increased, but when the sludge amount exceeded 30%, the cumulative gas production gradually decreased. With the addition of sludge, the methane production stage of the gas production process was significantly advanced, and the CH₄ content in the degradation gas production increased, which shortened the time required for the landfill to stabilize. However, there is a certain range for the amount of sludge that can be added. In the experiments, the mixture with 30% sludge amount exhibited the fastest degradation rate.

Key words: sludge, municipal solid waste, mixed landfill, gas generation process, dynamic model