摘要：Sustainable management of municipal solid waste is one of the major challenges for authorities in developing countries. Current waste disposal methods in Pakistan and other developing countries are not meeting standards of any proper waste management system opted for in the developed world. This mismanagement of waste is leading to serious environmental problems at local as well as global levels. This study aims to investigate the methane emissions from waste dumpsites in the city of Karachi, Pakistan, and to propose an effective approach to enhance their environmental sustainability. The methane emissions from waste disposal sites were assessed by simulating four different landfill situations during the landfill simulation reactor experiment. The residual methane reduction potential of each waste disposal approach was assessed by a biochemical methane test of waste after the experiment. It is estimated that in the present situation, about 11,500 tons of CO<sub>2</sub>-eq methane is released annually from waste disposal sites in Karachi. The convectional anaerobic landfill with methane capturing facilities and post-aeration operation was found to be the most environmentally sustainable approach with controlling 65% of residual methane emissions in comparison with the present scenario. For the development of new landfill sites, we recommend the bioreactor landfill approach with methane recovery and post-care (in-situ aeration).
