LCA of a consortium-based MSW management system to quantify the decrease in environmental impacts achieved for increasing separate collection rates and other modifications

In this study, the collection, transport, and treatment phases (including the management of products and processing residues) of six fractions of municipal solid waste (MSW) generated in the Sinistra Piave Basin (Veneto, Italy), a consortium of 44 municipalities, were analyzed by life-cycle assessment (LCA). Specifically, two different scenarios were assessed for paper and cardboard, glass, multi-material (plastics and metals), food waste, garden waste, and dry residual fraction management, one referring to the year 2015 and the other to 2004. The primary aim was to investigate what consequences the increase in separate collection rates progressively achieved by the consortium (65% in 2004 versus to 80% in 2015) exerted on the management system and its potential environmental impacts. For each scenario, the type of separate collection method employed (door-to-door in 2015, and mixed door-to-door and curbside collection in 2004), the collected amounts, the geographic location of the main sorting/treatment plants, and the type of treatments applied to manage the products and processing residues were considered. The results of the study indicate that, among the variations that occurred in the management system for the two considered years, the increase in separate collection rate achieved was the factor that most affected all of the potential environmental impacts taken into account. In particular, for the 2015 scenario, differently from the 2004 one, all of the categories considered (apart from ecotoxicity) were negative, indicating savings instead of impacts. Treatment was the stage that by far mostly affected potential environmental savings, with regard to paper and cardboard recycling in particular.