Sustainability assessment of industrial waste treatment processes: The case of automotive shredder residue

To date numerous environmental, economic and societal indicators have been applied to evaluate and compare the sustainability of products and processes. This study presents a set of ad hoc sustainability indicators suitable for assessing and comparing processes for the treatment of industrial waste streams and for allowing to address efficiently all aspects of sustainability. This set consists of the following indicators: energy intensity, material intensity, water consumption, land use, global warming, human toxicity and treatment cost. The application of these indicators to industrial waste treatment processes is discussed in depth. A distinction is made between direct contributions to sustainability, occurring at the process level itself, and indirect contributions related to the production of auxiliaries and the recovery of end products. The proposed sustainability assessment method is applied to treatment processes for automotive shredder residue (ASR), a complex and heterogeneous waste stream with hazardous characteristics. Although different strategies for recycling and valorization of ASR were developed, with some of them already commercialized, large quantities of ASR are still commonly landfilled. This study concludes that for ASR the most sustainable alternative to the present landfill practice, both in short and long term perspective, consists of recycling combined with energetic valorization of the residual fraction. (C) 2012 Elsevier B.V. All rights reserved.