How to enhance the environmental sustainability of WEEE plastics management: An LCA study.

A new management scheme of plastics from waste of electrical and electronic equipment (WEEE), which includes novel treatments of sorting, dissolution/precipitation, extrusion, catalytic pyrolysis, and plastic upgrading, is proposed. Its environmental performances are quantified by an attributional Life Cycle Assessment and compared with those of European currently adopted schemes, which include conventional mechanical recycling and thermal treatments as well as improper options of dumping and open burning, largely applied to WEEE plastics exported to developing countries. The proposed innovative scheme greatly enhances the environmental sustainability of WEEE plastics management, by increasing the annual amounts of polymers sent to recycling (from 390 kt/y up to 530 kt/y), decreasing residues to be sent to combustion (from 360 kt/y up to 60 kt/y), and reducing the potential impacts of all the midpoint categories under analysis (up to 580% for that of Global Warming). These results are mainly related to the adoption of a dissolution/precipitation process, which allows recovering target polymers such as ABS, HIPS and PC, with improvements in terms of Global Warming, Non-Carcinogens, and Carcinogens equal to 246%, 69% and 35%, even when the stages of polymer upgrading and catalytic pyrolysis are not included in the analysis. The sensitivity analysis shows that advantages of the new approach substantially disappear if the awful contributions of exportation outside Europe are taken into account. This clearly indicates that the first step to enhance the sustainability of WEEE plastics management is a strong limitation of improper treatments applied to exported wastes.

About the environmental sustainability of the European management of WEEE plastics.

A huge increase of waste of electrical and electronic equipment (WEEE) is observing everywhere in the world. Plastic component in this waste is more than 20% of the total and allows important environmental advantages if well treated and recycled. The resource recovery from WEEE plastics is characterised by technical difficulties and environmental concerns, mainly related to the waste composition (several engineering polymers, most of which containing heavy metals, additives and brominated flame retardants) and the common utilisation of sub-standard treatments for exported waste. An attributional Life Cycle Assessment quantifies the environmental performances of available management processes for WEEE plastics, those in compliance with the European Directives and the so-called substandard treatments. The results highlight the awful negative contributions of waste exportation and associated improper treatments, and the poor sustainability of the current management scheme. The ideal scenario of complete compliance with European Directives is the only one with an almost negligible effect on the environment, but it is far away from the reality. The analysed real scenarios have strongly negative effects, which become dramatic when exportation outside Europe is included in the waste management scheme. The largely adopted options of uncontrolled open burning and illegal open dumping produce huge impacts in terms of carcinogens (3.5·10+7 and 3.6·10+4 person⋅year, respectively) and non-carcinogens (1.7·10+8 and 2.0·10+6 person⋅year) potentials, which overwhelm all the other potential impacts. The study quantifies the necessity of strong reductions of WEEE plastics exportation and accurate monitoring of the quality of extra-Europe infrastructures that receive the waste.