Assessment of environmental sustainability of solid waste management system of Dhaka city through life cycle analysis

Dhaka, the highly populated capital of Bangladesh, generates a huge amount of solid waste that goes directly into the landfills posing a serious threat to public health, and land use. In this study, the current and some feasible alternative treatment strategies were assessed through life cycle analysis to find an answer for a sustainable waste management approach for Dhaka city. Four alternative waste management strategies: Landfilling + Composting (A1), Landfilling + Composting + Incineration (A2 & A3; variation in waste percentage), and Landfill + Incineration (A4) were structured to compare the environmental impacts with the baseline Landfilling scenario (B0). The Life Cycle Inventory (LCI) was constructed by blending the unit waste databases from ecoinvent 3.8, and field reports to project a representative municipal solid waste (MSW) scenario. Organic waste was found to be the major fraction of MSW. The life cycle impact analysis indicated that Scenario A2, with approximately 75% composting and 8.8% incineration of the collected waste, was the most environmentally friendly strategy in most impact assessment categories such as fine particulate matter formation, freshwater eutrophication, marine eutrophication and ecotoxicity etc. The second cleanest option, A1, reduced the burden of freshwater ecotoxicity, human carcinogenic toxicity, and terrestrial ecotoxicity the most. Compared to the baseline B0 practice, composting and incineration favored land use but composting was found to be the most feasible land use option in the long run. The electricity generation from the incineration of major waste fraction was only 3-5% of the concurrent requirement.