Life Cycle Impact Assessment of Municipal Solid Waste Management Systems: Improved design for environmental footprint minimization

Climate change is one of the most challenging issues of the latest decades. Growing awareness is emerging in a heterogenous audience, and it is predominant in the energy sector, where both producers and consumers behaviours have a direct consequence on the environment. In this context, the present paper aims at investigating the environmental impact of the energy valorisation of the organic matter from municipal solid waste in a real site in Italy. The municipal solid waste management system under investigation is composed by different sub-areas such as mechanical-biological treatment unit for organic matter separation, anaerobic digestion in mesophile regime, composting facility for compost production and a sanitary landfill for final deposition of unrecyclable waste. In this paper, a Life Cycle Assessment (LCA) is carried out with respect to the anaerobic digestion and the related biogas use in a cogenerative internal combustion engine, integrated with a sanitary landfill for final waste disposal. The novelty stands in the application of the LCA methodology for a new-built integrated system when policies of recovery and re-use are sought. Energy and mass flows related to this system have been implemented in Simapro 9.1.1.7. The entire environmental footprint of the system has been calculated with different LCA analyses, each one representing a specific aspect of the system (material and energy use, uncertainties, sensitivity). The outcome clearly depicts the benefits provided by the compost obtained from organic waste, as well as the energy and fuel savings brought by cogenerative solutions.