Life Cycle Assessment of Municipal Solid Waste Management in Kathmandu, Nepal

Abstract

The study is focused on the life cycle assessment of municipal solid waste management of Kathmandu city. Total waste generated in a year was taken as a functional unit (FU) in the study to compare three different scenarios: 1.) Business as usual (BAU) consisting of collection, transport, and landfilling; 2.) Energy recovery along with recycling; and 3.) Conjunctive disposal system comprising of composting and landfilling. The primary and secondary data were collected from Environment Department and Solid Waste Management Section of Kathmandu city and Solid Waste Management Technical Support Center of Government of Nepal. The life cycle inventory was developed with detail unit process by quantifying values of various resources and emissions. Life cycle impact assessment was performed to compute impacts on the environment. The contribution of this process to the environment was calculated as global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), and fuel energy consumption (FEC).

The results obtained from the quantification of environmental impacts were compared. It was found that the Scenario 3 is more eco-friendly than Scenario 1 and Scenario 2. The findings were fundamentally based on the environmental burden of waste managed in landfill regardless of recycling and composting. At the end, GWP, AP, EP, and FEC were calculated for each scenario and compared in kg equivalents per metric ton of waste managed in landfill (Table 1).

The comparative study of environmental impacts was performed and we calculated GWP, AP and EP for the total waste managed in a year. Table 1 also includes emission for annual waste management. The results obtained warrant a need for sustainable waste management methods for Kathmandu considering the conjunctive disposal system with composting and landfilling that reduces all four environmental impacts excluding the inefficient collection system, low public participation, landfill location, and operational improvements.

As indicated above, Scenario 3 was found to be an option with minimum environmental impacts (less GWP, AP, and EP) and cheaper fuel cost. At the same time, the results are influenced by higher composition of organic waste that can be composted and the GWP, which can be controlled. The results of this study can be applied for an integrated solid waste management system as an environmental tool.