LCA of a Consortium-Based MSW Management System to Quantify the Decrease in Environmental Impacts Achieved for Increasing Separate Collection Rates and Other Modifications

Giulia Costa,Alessio Lieto,Francesco Lombardi

doi:10.3390/su11102810

Giulia Costa, Alessio Lieto + Show 1 more

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https://doi.org/10.3390/su11102810

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Abstract

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.

Highlights

Generated around 29.6 million tons of municipal solid waste (MSW) in 2017 [1]
For MSW recycling, apart from the amounts of paper and cardboard, glass, metals, and plastics for recycling, the amount of biodegradable fractions entering aerobic or anaerobic treatment was counted as recycled for both scenarios, since the treatment plants generated compost that was used as a recycled product
The fact that high separate collection rates result in negative impacts is in agreement with the findings reported by many previous studies (e.g., References [5,14,15,25,26])

Summary

Introduction

Generated around 29.6 million tons of municipal solid waste (MSW) in 2017 [1]. As for the management systems adopted, very pronounced differences may be noted depending on the geographic area considered, and in general between northern and central or southern regions, both in terms of collection methods and treatment strategies applied. The current national waste report states that, in 2017, 16.4 million tons of MSW was intercepted by separate collection, which means that an overall collection rate of just over 55.5% was attained countrywide [1], still below the 2012 target. Northeast regions such as Veneto, Lombardy, and Trentino Alto Adige reached, and in some areas even greatly exceeded, this target [3,4]. High separate collection rates should lead to higher material recycling and, lower overall environmental impacts of the waste management system (e.g., References [5,6]). In a long-term perspective, recycling should lead to a decrease in the requirement of raw materials needed for production and, postpone the exhaustion of scarce resources; in addition to the recycling rate, product lifetime and the production growth rate are important factors [8]

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