Dr Lijuan Wang, with Professor Yong Yan from the School of Engineering and Digital Arts and Simon Barnes from Kent Research and Innovation have been working together on a project funded by the Scottish Enterprise Can Do Innovation Fund and the Scottish Environment Protection Agency (SEPA) to increase the effectiveness of plastic recycling.
When we put recycling in our containers at home and work, they go to a Materials Recovery Facility (MRF) where they are initial sorted by primary material type and then compressed and baled. However, there is no consistent method to show what a bale of compressed plastic bottles is made up of. In fact, a considerable volume of plastic material presented for recycling is of poor quality, contaminated with a wide range of materials unsuitable for recycling, both plastic and non-plastic.
Currently the sole method of identification is by eyesight and human experience. However, the research team from Kent have used a combination of advanced spectrum imaging and machine learning algorithms to accurately identify the type of plastic and other materials in a bale.
The research outcomes based on this project were presented at the Global Research and Innovation in Plastic Sustainability Conference (GRIPS 2021). Results from this project have helped a clearer and more accurate definition of the quality of materials, which will result in more transparent pricing and greater clarity in global trade of waste plastics.
Further research will be undertaken to develop the technology toward adoption in the plastics recycling sector, to drive up quality of recyclate, which will mean better environment performance for sustainable, recyclable plastics.