Producing lighter PET bottles has been embraced by manufacturers to cut carbon emissions and costs but some recyclers claim this can result in bottles ending up in landfill.
Jonathan Short, managing director of Eco Plastics told MRW that density separation processors have difficulties in detecting the lighter bottles.
As bottles walls become thinner they become similar to their labels, making separation more challenging and increasing the likelihood of “losing the PET with the label”, he added.
Chris Dow, chief executive of Closed Loop Recycling, said only a small amount of bottles end up in landfill because they are too light but that it was a growing trend: “A right thickness [threshold] should be established to avoid bottles going to landfill.”
WRAP - which published a report in 2007 on the benefits of lightweighting - echoed Dow’s call for a discussions between manufacturers and recyclers to establish a thickness threshold.
Claire Shrewsbury, packaging programme area manager at WRAP told MRW: “If producers are thinking about taking this route then we would recommend that they consider the recyclability, talk to recyclers and have them tested.”
Coca Cola Enterprises (CCE) has championed the practice of ‘lightweighting’ plastic bottles. The soft drinks giant’s 500ml bottles used to weigh 36g, and now they are less than 20g.
CCE associate director for recycling Nick Brown said that, because of the waste hierarchy, it was important to optimise the amount of packaging used by producers, and said CCE would continue to reduce its packaging.
“This makes a real environmental impact, and we will continue to drive in this direction as material science and manufacturing processes become more sophisticated,” Brown added.
Other obstacles to PET bottle recycling include bottle labels made of PVC, glue used to adhere labels to bottles and large labels preventing scanners from recognising the colour of plastic beneath.
Improving product design to take into account recyclability is one of the pillars of the circular economy, a concept which has recently been backed by resource minister Lord de Mauley.
But Bob Pringle, a former lecturer on waste reduction and recycling at the Scotland’s Rural College and Edinburgh University, expressed scepticism about a design process focused more on recyclability, in a comment article for MRW.
“Ease of packaging reuse, recycling or disposal is way down the packaging designers’ list of priorities,” he said.
Eco Plastics’ Short said that it was possible for manufacturers to design bottles with both commerce and recycling in mind. “The innovation is out there, manufacturers need to understand the benefits of it,” he added.