Abstract: A certain kitchen waste treatment plant in the eastern part of Beijing went into operation in 2007. After the comprehensive implementation of waste classification in Beijing, the characteristics of kitchen waste have changed significantly, resulting in the unstable operation of the plant. In 2023, the plant changed the pretreatment system from the mechanical crushing + mechanical pressing pulping process to the hydropulping pretreatment, and changed the dry anaerobic process to the wet anaerobic process. Moreover, the equipment of the deodorization system was replaced. After the renovation, the system has adapted to the new characteristics of the waste and achieved stable operation. The slag discharge rate of the pretreatment system is approximately 20%, and the water content of the discharged slag is about 70%. The gas production rate of the anaerobic system reaches 65 m3/t, and the methane concentration in the biogas is approximately 57%. The designed air volume of the deodorization system has been reduced by 50%, and the concentration of organized odor emissions is lower than 1 000 (dimensionless). The engineering example and relevant experience of the renovation could provide some reference for the construction or renovation of similar projects.

Key words: kitchen waste, waste classification, hydropulping pretreatment, wet anaerobic digestion