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.
Dr Woon is an Associate Professor and Head of PhD Program of New Energy Science and Engineering at Xiamen University Malaysia, a Professional Technologist by the Malaysia Board of Technologists, and a Green Building Accredited Professional by REHDA Malaysia. He advocates achieving transformative resilience for climate and environmental sustainability in waste and wastewater management, green building, renewable energy, and green mobility. He is passionate about utilizing systems-analytical approaches such as life cycle assessment, multi-objective optimization, artificial intelligence, pinch analysis, material flow analysis, and P-graph analysis on issues related to the environment-economic-social well-being nexus. He has published 50 papers, with over half in WoS Q1/Q2 journals as the first/corresponding author. He serves as the editorial board member of Green and Low-Carbon Economy, and guest editor of several WoS/Scopus-indexed journals such as Cleaner Engineering and Technology, Frontiers in Sustainability, Sustainability, and Energies. He received his PhD in Environmental Engineering from the Hong Kong University of Science and Technology.
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