Title: Circular economy for municipal solid waste to resources symbiosis network development

Abstract

Municipal solid waste (MSW) is a universal issue affecting all countries. The current MSW handling process by mainly disposing into open landfills has adverse environmental effects and is economically unfavorable. Due to the heterogeneous characteristics of MSW, a combination of different waste processing facilities with simultaneous cost and greenhouse gas (GHG) minimization needs to be performed for developing circular waste management. Taking Malaysia as a case study, a multi-objective MSW management model is established using the mixed-integer linear programming with augmented ε-constraint method version 2 to circumvent the limitation of the conventional weighting method. The model determines the optimum MSW allocation on seven waste processing facilities, including open landfills, material recycling facilities, sanitary landfills, anaerobic digestion, composting, incineration, and plasma gasification. Compared to the current scenario in Malaysia, the least-cost solution shows a 26% reduction for both cost and GHG emissions, while the least GHG emissions solution indicates a 159% reduction of GHG emissions with a 15% increase in cost. The sensitivity analysis demonstrates that plasma gasification is more favorable when electricity prices increase. A change in waste separation rate from 30% to 90% reduces total MSW management cost and the net GHG emissions by 18.24 MYR/tonne MSW and 0.30 tonne CO2-eq/tonne MSW, respectively. This study aligns with SDG 12 and SDG 13 and provides quantitative information to policymakers in developing a resilient and resource-efficient MSW management system in Malaysia. While the study takes Malaysia as a case study, the developed model can apply to other places facing a similar MSW disposal dilemma.