LCA Analysis of Different MSW Treatment Approaches in the Light of Energy and Sustainability Perspectives

This study concerns with a theoretical investigation on the disposal and valorisation of Municipal Solid Waste (MSW) through a challenging approach, based on the separation of MSW into two different fractions: Refuse Derived Fuel (RDF) and Organic Fraction Municipal Solid Waste (OFMSW). Both fractions are energetically valorised through gasification and anaerobic digestion (AD) processes respectively, in both cases gas streams were burned to produce electrical and thermal energy. The sustainability of the processes from the environmental as well as the energetic point of view, has been pursued, to find out if it can represent a viable alternative to the problem raised by the management of MSW and their landfill containment. Following the Life Cycle Analysis (LCA) approach, each stream of the processes has been analyzed in order to evaluate the environmental performances. On the other hand, the energy sustainability analysis has been carried out following the evaluation of two indexes: the Energy Sustainability Index (ESI) and the Energy Return of Investment (EROI). Results highlight that this process is more sustainable than landfill technology, in particular for “global warming”, “photochemical oxidation” and “eutrophication” impact parameters of CML2001, and categories connected with “Human Heath” of Eco-indicator99 method; the comparison with traditional landfill option shows that the environmental impacts are less than 10%. The proposed MSW treatment approach is less sustainable than landfill for only two categories: “acidification/eutrophication” and “minerals”. In merit to the energy sustainability analysis, the system results to have a positive merit: it produces a surplus of “Useful Energy”.