Greenhouse gas emissions and cost assessments of municipal solid waste treatment and final disposal in Maputo City

摘要

The goal in this study is to assess the greenhouse gas (GHG) emissions and the costs of municipal solid waste treatment and final disposal alternatives, in Maputo City, capital of Mozambique. Three scenarios were considered: first, the current practice of open dumping; second, the sole usage of sanitary landfilling; and third, comprising material recovery through recycling and biological treatment by composting or anaerobic digestion, and the usage of sanitary landfilling. The highest GHG emissions were observed in the second scenario with a released amount of 260,621t of CO2-eq/year, followed by the current scenario with 201,112t of CO2-eq/year. Both variants of the third scenario showed negative net emissions of -296,008t of CO2-eq/year and -223,925t of CO2-eq/year, due to the combination of GHG avoiding alternatives such as composting and biogas production as well as recycling. The cost assessment pointed towards the second scenario being the highest cost-saving scenario, requiring less than US$ 1 million/year and the current scenario as the most cost-intensive scenario, requiring around US$ 27 million/yearwith a contribution from the cost of inaction of US$ 24 million/year. In addition, sensitivity analysis was performed by changing the waste compositing in relation to different income levels, which have verified the consistency of results. It also showed that with income increase in the future, GHG emissions will increase in the current and for the second scenario, while for the third scenario, the GHG emissions will reduce and the portion of recyclables will significantly increase.