Waste-to-energy effect in municipal solid waste treatment for small cities in Brazil

The most common urban solid waste disposal in Brazil is the landfill. Additionally, there are still inadequate disposal units (dumps), but there are technological alternatives for this disposal and some projects are already installed in Brazil. The economic analysis is therefore fundamental to find the best technological option, transforming an environmental problem into a viable solution. This work presents a brief review of recent literature on Waste-to-Energy technologies, projects in operation in Brazil and proposes an innovative approach to analyzing the financial viability of the combination of consolidated destinations for the management of Municipal Solid Waste (MSW) (technological routes), that use waste to energy, considering the complementation of revenues for small cities with populations from 30,000 to 250,000 residents, through the implementation of a rate-payers contribution optimization algorithm. A structured algorithm was used with a focus on estimating revenue from the minimum value of rate payers' contributions (RPC) to make these routes viable for most cities considered in the project. Economic indicators used include: Net Present Value (NPV), Internal Rate of Return (IRR), Discounted Payback Period (DPP), and Leveled Cost of Electricity (LCOE). A sensitivity analysis of the two best routes was performed (depending on lower RPC values) based on NPV. The results tend to confirm solutions that can be approved not only by the government, but also by the business sector. The best outcomes are the routes with landfill and landfill gas, and with recycling and anaerobic digestion, considering the sale of digestate and landfill. These presented the best financial values, with discounted payback periods of 15 and 20 years, maximum RPC of US$0.04 and US$0.33, per inhabitant/month, respectively, with an IRR of 11.61%, for both. The sensitivity analysis indicated a greater influence on the investment costs of landfill gas for the first route and for the second route, the urban collection and cleaning services.