Diffraction grating shows potential for sorting food contact packaging
Axion said the sorting technology could increase recycling of an estimated 180,000 tonnes of polypropylene (PP) pots, tubs and trays annually in the UK, of which more than 60% is food contact packaging.
The firm’s research for WRAP focused on a process involving marking food contact PP packaging with lines (a diffraction grating) that can be scanned by a laser to reflect a specific pattern, which is captured by a camera connected to a computerised image recognition system able to identify the marked food contact PP packaging.
It could also work for high density polyethylene (HDPE) and polyethylene terephthalate (PET).
Axion estimated that the capital cost for a single diffraction grating sorting unit, including conveyors and ancillary equipment, at £500,000 with a potential payback within four years.
Liz Morrish, Axion senior consultant, said: “Challenges remain, including the need to widen applications and markets for this technology.
“It is also crucial for retailers, manufacturers and machinery suppliers to adopt agreed industry-wide methods that would optimise the identification and subsequent recycling of these waste streams.”
