Comparative assessment of waste disposal systems and technologies with regard to greenhouse gas emissions: A case study of municipal solid waste treatment options in China

Abstract

Municipal solid waste (MSW) management has shifted to include multiple functions, especially energy recovery and reduction of greenhouse gas emissions, other than sanitary treatment of waste. In China, two main MSW treatment options exist: landfill and incineration. The objective of this study was to evaluate the landfill and incineration methods in terms of two important indicators, energy balance and greenhouse gas (GHG) emissions, and to discuss the advantages as they relate to decarbonization policy. We set up two landfill cases: LF-Anaero, which adopted an anaerobic landfill structure, and LF-SAero, which adopted a semi-aerobic landfill structure. Two incineration cases were also established: INC-Non, where the MSW was not subjected to separated collection of non-burnable waste, and INC-Sep, where separated collection was conducted. Two conditions were also established. In the one-year condition, waste was assumed to entirely decompose in one year, whereas in the variable decomposition condition, the rate varied. Under the one-year condition, INC-Sep gave the best results for both energy balance and GHG emission reduction. When the decomposition rate of landfilled waste was considered, LF-SAero and INC-Sep had very similar cumulative amounts of GHG emissions after 50 years. However, in INC-Sep, the emissions all occurred in the first 20 years. In LF-SAero, about one-third of the emissions were accounted for in the last 30 years (after the landfill was out of service). Thus, this landfill method must be considered as a GHG emission source for a longer period when considering the total global warming impact. We concluded that INC-Sep is the superior technological option.