982983 - Development of Solid Waste Management Life Cycle Assessment Tool for Developing Countries

Solid waste management (SWM) is a pressing problem for many cities in developing countries. In low-income and middle-income countries, open dumpsites are used to dispose of over 80% solid wastes, currently serving around 3.5-4 billion people. This number is expected to grow with increased urbanization and population growth (ISWA, 2015).
Decision support tools can help communities in developing countries replace open dumps with the most environmentally friendly or economical waste management option. Most existing SWM decision support tools, however, have built-in data default values for developed countries, e.g. emission rates for waste handling equipment and capital and operating costs. Thus, the overall goal of this research was to develop a SWM decision-support tool for developing countries. Specific objectives were:
1) To develop the Solid Waste Assessment Tool (SWAT).
2) To illustrate the use of the tool by conducting case studies for 2 municipalities in Gujarat, India.
3) To analyze the results to understand how optimizing for the lowest cost, greenhouse gases (GHG) emissions, and diesel consumption can affect SWM decisions.
SWAT is a user-friendly Excel spreadsheet tool, which includes SWM collection and processing/disposal options common in developing countries, such as vermi-composting, regional landfills, and open dumps. In the current version of SWAT, many default values are for India, but the user can input other developing country-specific values. SWAT can optimize the percent of waste going to each processing/disposal option based on lowest cost, greenhouse gas emissions, or diesel consumption, by solving linear and nonlinear equations in less than five minutes.
Two case studies of urban cities, Vapi municipality with population of 300-450,000 and Ahmedabad Municipal Corporation with population of 5.5-6.5 million, were developed. Input data for SWAT was collected through site visits to these municipalities.
Over 75 SWAT- trials were executed by varying constraints, tonnage, and constants during optimization. Results indicated that increasing the waste fraction diverted to vermi-composting and regional landfills would reduce GHG emissions. Relatedly, the trials found that when the cost was low, GHG emissions were high, and when GHG emissions were low, diesel consumption was high. Thus, sending waste to open dumps increases GHG emissions. Considering these interdependencies can be helpful in selecting the preferred SWM option, based on community priorities.