Life cycle assessment of municipal solid waste treatment to energy options: Case study of KARTAMANTUL region, Yogyakarta

Various methods of solid waste treatment are available. However, due to heterogeneity characteristic of solid waste, determined the best means to manage solid waste in environmental view of point is not straightforward. In this case, solid waste management scenarios and an environmental analysis tool are required. This study compared various energetic valorization options with each other using the simplified Life Cycle Assessment (LCA) methodology. These scenarios were landfilling without energy recovery as a representative of existing solid waste management, landfilling with energy recovery, combination of incineration and anaerobic digestion, combination of gasification and anaerobic digestion, direct incineration, and direct gasification. A case study area in a typical KARTAMANTUL (acronym of three cities: Yogyakarta, Sleman, Bantul) intercity region in province of Yogyakarta, Indonesia. One ton of solid waste treated was defined as the functional unit of the systems studied. The Life Cycle Inventory (LCI) analysis was done by including field and laboratory survey to characterize solid waste in area study and using emission factors which were adopted from literature to estimate environmental burdens for each scenario. Inventory’s result was classified into impact categories, i.e. global warming, acidification, eutrophication, and photochemical oxidant formation. The indicators of categories were quantified by using the equivalence factors of relevant emissions to determine the environmental performance of each scenario. The study shown that in most of the impact categories (except acidification), a scenario with direct gasification indicated the best environmental profile. A sensitivity analysis was also conducted to examine change in outcomes for a variety of organic biowaste inputs, but had no significant effect on the overall result.