Guest Speaker: Dr. Tiziana Lai

Today we heard from Dr. Tiziana Lai, of the University of Cagliari. Her talk was interesting and raised a few concerns, so I thought I would write about her presentation. Dr. Lai lectured on the generation and management of end-of-life vehicles in Italy. First, she explained that the EU produces 6.5 million tons of end-of-life vehicle waste per year and of that, Italy generates 0.9 tons. Italy’s management of end-of-life vehicles is on par with the EU’s recycling and recovery, but both failed to meet the 95% goal by 2015. According to the European Union’s direction, this 95% goal should include 85% reuse and recovery, and 10% waste to energy.

End-of-life vehicles are first depolluted, then they are scrapped and shredded to produce automotive shredder residue (ASR). The residual mix is divided into two fractions: heavy and light fraction. The heavy fraction consists of mainly of glass and metals, which make up approximately 25% of the ASR. It also includes soil and sand, which can make up anywhere between 0 and 2.5% of the ASR. The light fraction of the ASR is made up of the plastics, textiles, and rubber. These elements make up 75% of the ASR.  

In Italy most ASR is place in a landfill, but there are other ways to improve this. To improve recycling, mechanical sorting could help to better manage the ASR, metals make up 13% of the automotive shredder residue, and can be extracted from the mix for reuse. The fine, heavy components of the ASR can be used as building materials. Plastics make up 45%, but they must be separated in to separate types in order to recycle. This presents a challenge, as many different plastics can be found in an end-of-life vehicle.

Another option is to use the ASR for thermal recovery. This can be done using the usual methods of co-combustion, pyrolysis, or gasification. However, ASR can also be used as an alternative fuel source for the cement and foundry industries. This interested me, as it presented a waste to energy option which benefited a specific industry, rather than just to society as a whole. This presents a unique market opportunity, in which these industries could profit from a mutual agreement.

Of course, there are limits to these options. There exists a risk of corrosion due to HCl in any area involved with end-of-life vehicles. Where thermos-chemical treatment occurs, high ash and varying moisture content are issues. End-of-life vehicles and in particular their ASR, could increase the heavy metal concentration in an area, resulting in extra costs for decontamination. Luckily, there are some methods to improve the management of end-of-life vehicles. Dr. Lai suggested the separation of the finest fractions, the removal of PVC via density separation to prevent it from burning, and finally the washing of the residue to remove the leachable fractions. She also discussed her own research, which involved the pretreatment of end-of-life vehicles via washing before final disposal. Her research showed a 60% removal rate of DOV, COD, and TKN.

Finally, she discussed a life cycle analysis of vehicles as a whole. Specifically, a more sustainable design could result in a vehicle made of fewer, greener materials. This reminded me of my Sustainable Business Practices class, which I took this last semester at NEU. Dr. Lai highlighted what I believe is a key aspect of sustainable waste management: source reduction. This is something I felt was under-represented on this dialogue, but it rests at the top of the hierarchy. Designers should design for sustainable disposal.  This would also reduce the amount and intensity of the waste management techniques, of which she suggested a combination of both mechanical separation and thermal recovery.