A comparative analysis of CH₄ emission reduction from municipal solid waste (MSW) under different scenarios in Kathmandu, Nepal

Abstract

Currently 516 tonnes of municipal solid waste per day are generated in Kathmandu, Nepal, the majority of which is taken to landfill. This is projected to rise to 745 tons per day by 2025. Landfill is a source of greenhouse gas emissions, most notably methane (CH₄). This study assessed the CH₄ emissions from a landfill site in Kathmandu for five scenarios: S0, S1, S2, S3 and S4. The results showed that CH₄ emissions are extremely high at 15,136 thousand m³ for scenario S0 - “Business as usual”. A significant reduction of 53% of CH⁴ emissions was achieved with gas capture (S1). Composting (S2) achieved a reduction of 35% reflecting the high organic content of waste that is currently landfilled. Recycling (S3) achieved a reduction of only 10%. Unsurprisingly, the greatest reduction in CH⁴ emissions occurred with a combination of gas capture, composting and recycling (S4) with a 73% reduction. The results suggest that gas capture and composting are feasible alternatives. Recycling material should also be considered, as plastics may in the future take up a greater proportion of the waste material over time.