Impacts of the collection and treatment of dry recyclables : commingling practices and their environmental and economic impacts: an analysis based on life-cycle assessment and life-cycle costing

This study focuses on the separation, collection and subsequent management of the dry recyclable fractions (i.e. beverage cartons, glass, metal, paper and cardboard, and plastic) of municipal waste in the EU-27. The goal of the study is to recommend compliant/noncompliant and, in general, best commingling practices for the separate collection of dry recyclables in view of the obligations set by the EU Waste Framework Directive and its upcoming revision. To this end, the study first identifies the most relevant collection and commingling practices for dry recyclables around the EU-27 and subsequently assesses the environmental and economic impacts of 65 different management practices with a view to providing evidence-based recommendations for the interpretation and, ultimately, revision of the EU Waste Framework Directive, with a special focus on the derogations from a strict separate collection of the recyclables. The results indicate that single-stream collection (commingling all dry recyclables together) incurs detrimental environmental and economic effects and should be avoided. Systems with three or four streams achieve comparable environmental and economic performances and are recommended, together with selected dual-stream systems where glass, metal and plastic are commingled, while paper and cardboard are collected in a separate stream or commingled with beverage cartons. There is no evidence that four-stream systems are better than three-stream systems or dual-stream systems when paper and cardboard are kept separate from the other light dry recyclables, suggesting that some degree of commingling can be safely accepted and even recommended in view of the potential benefits of reducing the overall number of streams collected (costs, space, convenience), although these were not assessed quantitatively in this study.