GREENHOUSE GAS EMISSIONS FROM DIFFERENT WASTE MANAGEMENT TECHNIQUES

Abstract

Impacts on environment because of municipal solid waste (MSW) management have been increased considerably in India, due to continuous increase in waste generation, and improper treatment and disposal of the waste. Improper disposal like open dumping and other treatment processes involved in the MSW management causes the emission of certain gases, which are harmful for both the human beings and environment. We analyze greenhouse gas (GHG) emissions from the Indian MSW sector for the five treatment processes: vermicomposting, aerobic composting, anaerobic digestion, burning and open dumping. We estimate these GHG for five cities, Mumbai, Kolkata, Hyderabad, Bangalore and Delhi as well as on national level. Six scenarios have been analysed in this study. Our results show that increase in recycling of waste material decreases the GHG emissions. It has been observed that the out of six waste treatment and disposal methods opted for the study; vermicomposting process has least GHG emissions — 0.08 million tonnes/day. Total GHG (CO2-eq) per kg of input waste is highest in anaerobic digestion 1.96 and followed by sanitary landfilling — 1.65. Total GHG (CO2-eq) per kg of input waste for anaerobic digestion, open dumping, vermicomposting, aerobic composting, burning and sanitary landfilling is. 1.96, 0.86, 0.15, 0.46, 0.70 and 1.65 respectively at 0% recycling rate. However, flaring or burning of methane generated from the anaerobic digestion process can reduce the total GHG emission, further GHG emissions can be reduced by the application of landfill with gas recovery system. In India annual total GHG (CO2-eq) emission from MSW sector is —144 million tonnes/yr. of which 89% is produced by the open dumping alone. The net annual GHG emission from Indian MSW is 87 million tonnes/yr. The net annual GHG (CO2-eq) emissions in three major cities (Mumbai, Kolkata, Delhi) are 1.10, 0.61 and 1.25 million tonnes/yr respectively. Keywords: Municipal solid waste management, Greenhouse gases, Anaerobic digestion, Open dumping, Composting, Climate change iii