During my work experience at Grain, I came across the concept of the circular economy, championed by the Ellen MacArthur Foundation. Its three principles are ‘Design out waste and pollution,’ ‘Keep products and materials in use,’ and ‘Regenerate natural systems.’ Particularly the first two principles point to recycling finite materials that aren’t biodegradable.
Why we need to recycle plastics
Recycling plastics is an essential step to minimise what escapes waste systems and mostly ends up in the oceans — by 2050 there is predicted to be more plastic in the sea than fish — and reducing what ends up in landfill (leaching toxins into the environment), or being incinerated in Energy from Waste plants. Not only is the waste harmful, but the oil plastic is produced from is a finite resource, so it’s also an economic waste not to make use of ‘waste’ plastic. Currently 37% of plastic in the UK is recycled, a decrease in previous years such as 2021 which saw 44.2% of plastics recycled by households.
How the plastics recycling system works
Mechanical recycling is the most common approach, where plastics are recovered without changing its basic polymeric structure. A growing approach to recycling is chemical recycling — where plastics are changed into products or substances used as raw materials for the manufacturing of products that include plastics — by changing its chemical structure.
Open and closed loop recycling
Closed loop recycling is the most ideal for a circular economy, as the recyclate produced is used for another product of the same category with a common example being PET bottles. On the other hand, open loop recycling uses the recyclate for a different product often with a longer life, such as HDPE bottles being made into plastic pipes. This is often seen as ‘downcycling’.
Researchers have discovered that the bacteria Ideonella sakaiensis can break down and consume PET plastics, leaving highly biodegradable PHB plastics. This could provide a new approach to PET recycling and the sustainable production of biodegradable plastics.
Another new approach to plastic recycling is catalytic technology: breaking down non-biodegradable polymers into useful, tiny organic molecules. Catalyst types used are thermocatalysts, electrocatalysts, and photocatalysts which use light as an energy source for controlled degradation of the plastic.
Plastics Europe represents European plastics manufacturers, and was rebranded by Grain in 2021, focusing on sustainable solutions in the plastics industry. Some of efforts of the trade association and its members include helping create more from recycled plastics, so plastic packaging waste becomes a valuable resource, working on designing products so they can be recycled, reducing greenhouse gas emissions from production processes, using more electricity from renewable sources, and even finding ways to recycle plastics into mattress foam. The industry just launched ‘The Plastics Transition: Our industry’s roadmap for plastics in Europe to be circular and have net-zero emissions by 2050′.
Limitations of recycling
While plastics recycling should be increased and further developed, plastics can’t be recycled indefinitely due to the recycling process affecting the polymer chain, so the most important stage is to reduce its use in the first place. In fact, when first introduced, recycling was used by plastics manufacturers to push the responsibility onto consumers and enable them to keep selling more. If no action is taken, greenhouse gas emissions from the production, use, and disposal of plastics could account for 19% of the Paris Agreement’s total allowable emissions in 2040 to limit warming to 1.5°C.