Economic analysis and life cycle impact assessment of municipal solid waste (MSW) disposal: A case study of Mumbai, India.

Municipal solid waste (MSW) management is a major concern in Indian cities. This work rigorously assesses the relative costs and the environmental and health benefits of alternative MSW management methods. Management of MSW over the next 20 years for the city of Greater Mumbai was considered. A generic model was developed to determine the costs for (i) dumping on open ground, (ii) sanitary landfill without leachate treatment, (iii) landfilling with leachate treatment and (iv) regional composting and landfilling. LandGEM was used to quantify the gaseous emissions from landfill, while emissions from leachate and composting were taken from literature. The life cycle impact model of one tonne of MSW was developed using OpenLCA software and the International Reference Life Cycle Data System (ILCD) 2011 method was used for impact assessment. The cost of disposal of one tonne of waste was found to be INR344 (US$5.17), INR741 (US$11.13) and INR1367 (US$20.53), respectively, for the first three scenarios. As compared to open dumping, landfill gas flaring reduced the global warming potential by 32% and leachate treatment reduced freshwater ecotoxicity and total human toxicity marginally, by 20% and 60%, respectively. Composting-landfilling was the most preferred option, with a cost of INR531 tonne (US$7.97), leading to a reduction in global warming potential by 79% and a slight decrease in freshwater ecotoxicity by 64%. Further, emissions due to accidental fires were also quantified. The study provides valuable insights for the selection of MSW management options for large metropolitan cities in developing countries.