Dynamic flow analysis of current and future end-of-life vehicles generation and lead content in automobile shredder residue

Since end-of-life vehicles (ELVs) contain toxic substances, they have to be treated properly. The purpose of this study was to obtain useful information for ELV management from the viewpoint of toxicity. We focused on lead as a representative toxic substance contained in vehicles and investigated the dynamic substance flow of lead contained in ELVs and its content in automobile shredder residue (ASR). A population balance model was used to estimate the number of ELVs generated between FYs (fiscal year) 1990-2020, employing a Weibull distribution for the lifespan distribution. Sixteen lead-containing components of the vehicle were considered. It was estimated that the annual number of ELVs generated would be 2.9 million as of FY2020. The results implied that it is hard to remove Pb completely. This is because 5,000-11,000 t-Pb will still remain in vehicles in use in FY2020 even though most components in new model vehicles could be replaced by lead-free alternatives. As of FY2010, the substance flow showed that Pb contained in ELVs amounted to 4,600-5,700 t-Pb. Of this, 13.2-14.0 % was contained in ASR. The Pb content in ASR could be dramatically decreased by FY2020, but it will continue to contain 240-420 mg-Pb/kg if the treatment system is not improved.