Life cycle assessment of potential municipal solid waste management strategies for Mumbai, India

Dumping of municipal solid waste into uncontrolled dumpsites is the most common method of waste disposal in most cities of India. These dumpsites are posing a serious challenge to environmental quality and sustainable development. Mumbai, which generates over 9000 t of municipal solid waste daily, also disposes of most of its waste in open dumps. It is important to analyse the impact of municipal solid waste disposal today and what would be the impact under integrated waste management schemes. In this study, life cycle assessment methodology was used to determine the impact of municipal solid waste management under different scenarios. Six different scenarios were developed as alternatives to the current practice of open dumping and partially bioreactor landfilling. The scenarios include landfill with biogas collection, incineration and different combinations of recycling, landfill, composting, anaerobic digestion and incineration. Global warming, acidification, eutrophication and human toxicity were assessed as environmental impact categories. The sensitivity analysis shows that if the recycling rate is increased from 10% to 90%, the environmental impacts as compared with present scenario would reduce from 998.43 kg CO₂ eq t^-1 of municipal solid waste, 0.124 kg SO₂ eq t^-1, 0.46 kg PO₄^-3 eq t^-1, 0.44 kg 1,4-DB eq t^-1 to 892.34 kg CO₂ eq t^-1, 0.121 kg SO₂ eq t^-1, 0.36 kg PO₄^-3 eq t^-1, 0.40 kg 1,4-DB eq t^-1, respectively. An integrated municipal solid waste management approach with a mix of recycling, composting, anaerobic digestion and landfill had the lowest overall environmental impact. The technologies, such as incineration, would reduce the global warming emission because of the highest avoided emissions, however, human toxicity would increase.