Plastic bottles, along with pots, tubs and trays (PTT), represent more than 70% of the plastics packaging collected every year for recycling in the UK.
Processing a significant proportion of this million tonnes-plus of household packaging is essential to meet “aggressive” plastics recycling targets, as recently described by resource minister Lord de Mauley.
The export of plastics material is now less viable because traditional recipient countries such as China have put up barriers to the entrance of low-quality materials. So developing a domestic market for bottles and PTT is vital for the UK.
The push towards more plastics recycling comes not only from recyclers, but also from packaging producers.
As the cost of raw materials keeps rising, the appeal of recycled polymers does too, especially when recycled plastics can be used in new food packaging.
Claire Shrewsbury, programme area manager for packaging at WRAP, told MRW: “One way to develop a recycling market is by adding the most value to the recyclate, which means [making it] food grade, because it is worth more than technical grade.”
PET bottles lead the way
With 92% of councils collecting such bottles, a recycling rate that has passed the 50% barrier, according to Recoup, and a £250-£300 per tonne price for recycled clear PET, bottle recycling is eco- and profit-friendly.
But despite progress and award-winning producer-recycler partnerships - such as the Continuum plant operated by Coca-Cola Enterprises and Eco Plastics - reprocessors warn that there are still factors affecting the quality of recycling, leading to food-grade PET being down-graded to non-food.
One factor is light-weighting: lighter bottles are not detected by separators and end up being excluded from the food-grade recycling process. PVC labels and aggressive, non-water soluble glues are other obstacles to closed loop recycling, as well as additives such as oxygen scavenger, a chemical that prevents gas from permeating the walls of the bottles to extend the shelf life of products.
“Oxygen scavenger reacts with the PET and produces a yellow flake, which cannot be reused in PET bottles because manufacturers want a clear flake,” said Jonathan Short, managing director of Eco Plastics. “A solution would be to put the scavenger in the cap of the bottles rather than in the walls.”
Short added that it would be perfectly viable for manufacturers to design bottles with both commerce and recycling in mind: “The innovation is out there; manufacturers need to understand the benefits.”
Such a view is shared by WRAP’s packaging team. It has been researching the issues affecting the quality of recycled PET and will publish the findings a report.
WRAP has also developed an online resource, the PET Categorisation Tool, where manufacturers can include details of their bottles, such as adhesive, barrier coatings, closure, colourants, label and size, to determine how easily they can be recycled.
Challenges to PTT recycling
Overcoming the obstacles to bottles recycling would mean obtaining higher quality PET that can re-enter the food packaging production chain. As the domestic market for the recycling of plastic bottles can now stand on its own two feet, the focus has shifted from quantity to quality.
The same cannot be said for PTT, the recycling rate of which is estimated at 20% in 2011, according to Recoup. Chief executive Stuart Foster said: “We would like to see much more market development to ensure that at least some of the ever- increasing amounts of PTT being collected can be recycled.
“We need to do that quickly, because if we cannot show that more auditable markets are available and do not recycle more PTT material in the next few years, the UK will really struggle to meet the 2017 target.”
According to Chris Hanlon, commercial manager at Biffa Polymers, which used to be one of the largest facilities for the recycling of PTT, the problem is that what is commonly referred as PTT is actually a low-quality mixed rigid feedstock.
“What people call PTT is not just plastics - it is everything left after other plastics materials are sorted,” he told MRW. “It should not even be called pots, tubs and trays.”
Finding that processing PTT was no longer economically viable, Biffa Polymers substituted the PTT feedstock used in its Redcar plant with a polypropylene (PP) one. PP is used for food and non-food packaging, and some 40% of PTT is made with it.
Biffa’s shift to PP may simply be regarded as a single company’s commercial decision. But it highlights how concentrating efforts on recovering PP could be the way forward to increase PTT recycling in the UK.
Foster said: “There is no single solution, but one option for PTT is more focus on collecting polyolefin plastics for recycling, such as PP, which is already where other countries focus their recycling efforts.”
So the challenge is to separate food-grade PP from the generic PTT stream and reprocess it into recycled PP that is compliant with food- grade standards. Following progress made with PET and HDPE, WRAP has been looking at PP recycling, with research on some innovative solutions promised in the next couple of months.
Wrap develops automatic sorter for PP
WRAP has piloted a system to sort PP food packaging automatically from non-food packaging using a process called diffraction gratings. This involves marking food packaging so that it can be detected by optical sorters.
Applying the technology at a national scale needs not only an effort from recyclers, but also from packaging manufacturers because they will need to include the marking system in the production process.
As with PET bottles, the key to advancement in the recycling of other plastics packaging is cross-industry co-operation.
Shrewsbury said: “What happened in the past was that one area of the supply chain pointed to another and said ‘I can’t do this because they can’t do that.’
“Solutions to delivering plastics recycling targets fall on everyone across the supply chain working together.”
The coming together of recyclers and packaging producers will be a significant step in the hike towards the 57% plastics recycling of 2017. But equally important will be to engage with the other stakeholders in the plastics cycle - consumers - to ensure that enough plastics packaging enters the recycling system.
And this could prove to be even more challenging than developing complex automatic sorting systems because behaviour change is often the most difficult issue to confront.
WRAP brings industries together
To facilitate cross-industry dialogue on increasing recycling, in February WRAP put together representatives of different areas of the supply chain in a steering group, the Plastics Industry Recycling Action Plan, chaired by Gareth Hollinshead, key account manager
at WRAP. The steering group includes representatives of the retail industry, such as the British Retail Consortium and the British Soft Drinks Association; plastics associations, such as the British Plastics Federation and the Packaging and Films Association; recycling associations, such as Recoup; government bodies, such as Defra; and local authorities.
The group will meet twice a year and oversee the progress of four sub-groups, which will focus on putting together action plans on:
- recyclability of packaging
- increasing collection rate
- sorting and processing
- development of market opportunities
The first meeting of the working groups will take place in September. WRAP’s Claire Shrewsbury said: “We already have some members, but if anyone is interested in joining and has idea for actions, we welcome them to come forward.”