A comparison among different automotive shredder residue treatment processes

European Community claims for end-of-vehicles (ELVs) targets of at least 85% recycling and 95% recovery rate by 2015. At present, only about 80% of ELV total weight is being recycled, whereas the remaining fraction of 20%, which is called automotive shredder residue (ASR), is disposed by landfilling in most of the EU countries. In this study a comparison has been carried out among five ASR management strategies, chosen after a screening of the most common technologies suitable and available nowadays, aiming at proposing alternatives to the current disposal in terms of benefits resulting from the conservation of nonrenewable resources and reduction of wastes disposal. These scenarios are ASR landfill disposal, the current status quo for a further nonferrous metals recovery, ASR incineration with energy recovery, an advanced material recovery followed by thermal treatment of ASR residue and a feedstock recycling by means of gasification. Life Cycle Assessment (LCA) methodology was applied in order to characterise and quantify the environmental impacts related to each scenario analysed, using the SimaPro 7.1 software and the Eco-indicator’99 method, according to a hierarchic approach. The analysis shows that recovering nonferrous metals ensures a reduction of the environmental loads related to resources depletion due to landfill disposal, but no significant benefit for human health end point can be observed. The ASR thermal treatment in incinerators allows both the decrease of impacts due to plastic fraction disposal and benefits from energy recovery, but a decrease of ecosystem quality occurs because of stack emissions. A net environmental performance upgrading seems to be ensured by those scenarios which include the application of post-shredder technologies. Industrial processes aimed to matter recovery, after shredding, resulted not only in a necessary solution to fit the European recovery and recycling targets for ELVs but also to the options that can obtain greater environmental benefits compared to present practises. However, further improvement can be achieved only by integrating end-of-life treatments into Eco-design strategies aiming at a more efficient separation of high value-added materials such as plastics and metals.