Optimization of municipal solid waste management system based on bi-level programming model

To efficiently predict the quantity of municipal solid waste in Beijing, the quantity forecasting model was established based on the combined forecasting model with variable weights and scenario analysis method. Results showed that MSW output in Beijing would rise slightly, but a shortage of disposal capacity would remain. On this basis, a bi-level programming (BLP-MG&MC) was presented, in which the upper-level objective was to control greenhouse gas (GHG) emissions and system cost minimization was placed at the lower-level objective. Results from the model indicated that composting and incineration would be the primary forms of MSW disposal. The total GHG emissions would reach 1.67×10⁶ t-CO2eq over the planning horizon and the CH4 emissions emitted from landfill facilities and N2O emissions associated with incineration facilities would be the major contributors to GHG emissions. The resulted system cost would amount to 7.0×10⁹ Yuan, with incineration and composting facilities responsible for about 65%. Comparative analysis of the four models revealed that the bi-level model would be conducive to providing compromised waste diversion schemes with both economic cost and environmental benefit.