Comparative evaluation of environmental efficiency of the municipal solid waste treatment scenarios for St. Petersburg region with the life cycle assessment method

Abstract

The research focuses on complex comparative evaluation of environmental efficiency of Municipal Solid Waste (MSW) treatment scenarios that can be implemented in St. Petersburg and Leningradskaya oblast’. Three scenarios were modelled that technically and economically meet the regional needs. The scenarios imply the following systems: 1) sorting, Mechanical-Biological Treatment (MBT), landfilling; 2) sorting, MBT, Waste-to-Energy (WTE), landfilling; 3) sorting, MBT, Refuse Derived Fuel (RDF) for cement industry, landfilling. In comparison, the “zero” scenario implying landfilling untreated waste was modelled. A Life Cycle Assessment based approach was proposed, which allows comparing scenarios through converting heterogeneous impact categories to a single monetary index. The highest damage reduction (by 60-70% in comparison with the “zero” scenario) was shown in the complex scenarios, including both MBT and energy recovery. 40, 42 and 47% of the total damage in scenarios 1, 2, 3 accordingly is associated with MBT product landfilling. The results show that the main benefit of complex treatment cannot be fully realized without separate collection of food waste. In this situation the most environmentally soundable scenario comprises recyclables separation and subsequent WTE treatment of all the rest with the exception of some non-combustibles.