Life cycle assessment of management strategies for municipal solid waste incineration residues: a case study on Tainan City

摘要

Municipal solid waste (MSW) management is an important issue for a modern city, and it is inevitable that some unrecyclable garbage will exist and need to be properly treated. In Taiwan, the recycling rate of MSW reached up to 58% in 2016, but there were still 3.13 million tons of unrecyclable garbage, among which 2.99 million tons were treated by incineration (~95.5%) [1]. The incineration process has two residues, i.e. fly ash (FA) and bottom ash (BA), and FA normally contains high levels of toxic substances and thus needs further treatments. The 24 public incinerators of Taiwan treated about 6.39 million tons of waste in 2016, and generated 199.9 thousand tons of FA. However, most of the FA was treated by a solidification/stabilization (S/S) process and then landfilled (~98.75%) [1], and this method consumed a significant amount of landfill space. Many cities and counties in Taiwan are now facing the problem of lack of landfill space, and therefore to find out an alternative method of FA treatment and disposal is urgent. The purpose of this study was to use life cycle assessment (LCA) methods for evaluating the global warming potential (GWP) and the cost of the melting technologies which are technically capable of replacing the S/S process for FA treatment.