Along with collection and sorting issues, the level of contamination in postconsumer recyclable plastics can make or break the bottom line of recycling operations. But contamination issues are gradually being negated through new technologies and practices.
1.) Better methods of recycling PET bottles, for example, are more aggressive in removing contamination. Contaminant-neutralizing alternative methods such as chemical PET recycling are also being commercialized in more efficient versions.
2.) As a basic example, improved sorting methods have allowed recycling facilities to process bottles along with their caps, which once were considered contaminants. There’s now also improved process tolerance for recycling bottles with full-length film sleeves, according to an Association of Postconsumer Plastic Recyclers report. (APR researchers have also reportedly discovered the percentage for how much PP contamnation can be tolerated in recycled HDPE without harming impact properties.)
3.) And collecting less-contaminated bag and related film increases the efficiency of film recycling -- but it will require better consumer education and more opportunities for them to drop off used bags at retailers, since bags and film collected curbside tend to be more contaminated.
Mike Tolinski is the author of Plastics and Sustainability, published in Oct. 2011 by Wiley-Scrivener, and he is Contributing Editor for Plastics Engineering magazine of the Society of Plastics Engineers in the USA. His views have been shaped by his engineering, university, and journalism experience in the plastics and manufacturing industries over the past 22 years. You can follow Mike and be alerted on blog updates via Twitter.