Life-cycle assessment of solid waste management in Dhulikhel Municipality, Nepal

Solid waste management is becoming a major environmental and public health concern in emerging municipalities in Nepal. In this study, the life-cycle assessment (LCA) approach is used to address the environmental impacts of potential waste-treatment scenarios in Dhulikhel Municipality in Nepal. The assessment was based on four different scenarios - namely, scenario 1, landfilling; scenario 2, composting combined with landfilling; scenario 3, recycling, composting and landfilling; and scenario 4, recycling, anaerobic digestion and landfilling. The LCA methodology was developed, including the benefits and impact potentials of different unit processes in each scenario, also taking into consideration emissions from energy use. The environmental impacts from the scenarios were compared in terms of global warming potential, acidification potential and eutrophication potential. Among the four scenarios, scenario 4 (i.e. with anaerobic digestion) showed the most environmental advantage. Scenarios without biological treatment facilities are the least preferred option, as their impact is significantly greater than those of other options. Therefore, organic waste is recommended not to be disposed of in landfill sites even if the transportation activity increases, because the magnitude of methane avoidance increases with an increased amount of waste diversion to the biological treatment units.