Abstract: With the advancement of the municipal solid waste (MSW) sorting system, the characteristics of MSW generation and substance flow in Shanghai, especially the kitchen and residual waste components and their treatment methods, have changed significantly, which directly affects the carbon emission of the MSW treatment process. The carbon emission and reduction under the background of MSW sorting policy in Shanghai were calculated using the benchmark method, focusing on kitchen and residual waste components. The results showed that from the second half of 2019 to 2022, the carbon reduction intensity of residual waste decreased from 0.19 t/t to 0.13 t/t， due to the decrease of the kitchen waste component and the increase of the rubber and plastic component in residual waste. The carbon reduction of kitchen waste increased significantly due to the anaerobic digestion treatment, and carbon emission reduction benefits gradually appeared. On the whole, the carbon reduction of kitchen and residual waste after MSW sorting was stabilized at 0.20-0.23 t/t. In the baseline scenario, the sensitivity analysis with incineration ratio as the key variable found that with the increase of the incineration ratio of MSW, the carbon emission reduction of project scenario decreased. The results of this study could bring reference value for evaluating the environmental performance of MSW sorting, and also provide ideas for carbon emission reduction strategies of the MSW treatment industry under the new situation.

Key words: municipal solid waste, MSW sorting, carbon accounting, carbon reduction, Shanghai city