Overview of Washing Systems for Commercial Cleaning of Plastics Separated from Automotive Shredded Residue

Using automated separation, a mixed plastic stream can be recovered from shredder residue (SR). However, the mixed plastics may be contaminated with dirt, oils, heavy metals, and substances of concern (SOCs). To remove these contaminates from the mixed plastics, the plastics must be washed and cleaned. According to the U.S. Environmental Protection Agency (U.S. EPA), the recovered mixed plastic needs to contain less than 2 ppm of Polychlorinated Biphenyls to be introduced into commerce, thereby setting the performance criteria for the washing systems. This paper describes the performance and safety criteria for the washing systems, the selected washing processes, and the factors contributing to the economy of mixed plastics washing.