Guidelines for safe closure and rehabilitation of municipal solid waste dumpsites in Sri Lanka
Municipal Solid Waste (MSW) management, particularly final disposal as open dumps has become a global issue. Worldwide, dumpsites are the third largest anthropogenic source of methane, accounting for 11 percent of estimated global methane emissions or 881 million tonnes of CO2 equivalent. The 50 largest dumpsites affect the daily lives of 64 million people, 17 million of whom live in Asia, and all dumpsites affect all 17 SDGs either directly or indirectly. Similarly, dumpsites have become a serious issue in Sri Lanka, which experienced the catastrophic collapse of one in Meethotamulla in 2017, causing 32 fatalities and the destruction of 87 houses. The lack of proper final disposal techniques has been the major bottleneck faced by many local authorities. A common grievance voiced by many local authorities is that insufficient land resources, technical support, and finances hinder the transition from open disposal to sanitary landfilling. However, it has been well recognized that open dumping practice can no longer be allowed to continue, and appropriate waste resources recovery and disposal strategies should be established at any cost. Thus, a simple guideline for dumpsite closure and rehabilitation is of paramount importance for local authorities which would help reduce pollution risks on the environment and public health at the local level and climate and SDG achievements at the global level. The term “dumpsite rehabilitation” in these guidelines refers to any work, including partial work carried out on a MSW dumpsite aimed at improving existing conditions to minimize the hazard risk caused by leachate contamination, gaseous emissions, waste burning, collapse due to instability, and all other associated socio-economic issues. Accordingly, these dumpsite rehabilitation guidelines aim to provide for or advise on: a) a risk assessment procedure to determine the level of pollution caused by a dump and its rehabilitation potential; b) implementable rehabilitation and closure plans; c) appropriate technical intervention to minimize leachate contamination, uncontrolled gaseous emissions, waste burning, and risk of dumpsite collapse; and d) an appropriate operation and maintenance procedure that ensures the sustainability of technical improvement measures.