GHG emission and carbon sequestration potential from MSW of Indian metro cities

•LandGEM, version 3.02 is used to compute GHG emission potential of MSW landfills.•Mumbai is found to be the highest contributor and Visakhapatnam the least in India.•A review of similar studies in India using different methodologies is also done.•The total GWP of emitted GHG is found to be 189,984 Gg of CO2 equivalent.•Mitigation measures are also suggested to reduce the GWP.

The rapid growth of urban population in India generates significant quantity of MSW (municipal solid waste), resulting in emission of GHGs (greenhouse gases). To quantify the impact of GHG emission on the account of dumping of MSW in unsecured landfill sites, 23 Indian metro cities are considered for a period of 20 years (2001–2020). Estimation of waste generated is computed using growth rate of present as well as past decades while GHG emitted are quantified using LandGEM software, version 3.02. The total GWP (global warming potential) of GHG emitted through dumping is found to be 189,984 Gg of CO2 equivalent which includes 88.44% contribution from CH4 and the balance due to CO2. The total carbon sequestered during landfilling is found as 47,474 Gg which may be lost as CO2 and ultimately adds to GHG emission, if RDF (refuse derived fuel) is produced or incinerated instead. To reduce GHG emission and to raise funds for MSW management authorities, CH4 could be utilized as a renewable energy resource. The adoption of sanitary landfill, power production/cogeneration, direct use of Btu gas and its up-gradation to vehicle fuel or pipeline-quality high-Btu gas are the suggested management practices to achieve the objective. Further, it opens the scope of LandGEM for computing the national inventories of GHG emission and initiates research in the field of carbon sequestration potential of MSW landfills in India.