Closing the Loop: a Sustainable Strategy for MSW Management with Zero Residues and Energy Production

he management of Municipal Solid Waste (MSW) has always represented an important challenge of our society, and it is a constantly evolving issue characterized by variable temporal and spatial specificities. Despite recent technological developments, Waste-to-Energy (WtE) approaches considering environmental and energy sustainability factors and their implementation in real contexts are rather scarce. Unsorted MSW (the residue aside from the differentiate collection of recyclables) can be divided into key fractions for WtE applications, such as the gasification of the Refuse Derived Fuel (RDF) cut or the anaerobic digestion (AD) of the Organic Fraction of Municipal Solid Waste (OFMSW); however, there are certain residues of these processes as well as other fractions of MSW which typically end up in landfills. The present ex-ante study evaluates the convenience of introducing a Plasma Torch (PT) in the management strategy for unsorted MSW replacing the landfill option. The research is based on the modeling of the PT, considering the possible feed streams to this unit. In addition, sensitivity studies are carried to shed light on suitable operating conditions (temperature, equivalence ratio, gasifying agent) and the convenience of the process is assessed from an environmental and energy point of view, by comparing the PT scenario with the baseline case of landfilling. The Life Cycle Assessment (LCA) suggests that the environmental loads can be significantly reduced (>80%) by introducing the PT unit, while the system shows an increase of more than 50 % in the Energy Sustainability Index (ESI).