Imagine if we had circular solutions for plastic that were perfect, carbon-zero, regenerative, socially and environmentally responsible and economically viable. Of course, this is not currently the case, and the avalanche of plastic has been gathering pace for decades. Since plastic became widely commercialised in the mid-20th century, the world has produced over 10 billion tonnes and thrown away almost 8 billion tonnes. Of the plastic in the UK, 37% has been sent for recycling, 44% incinerated for energy recovery, and 19% has gone to landfill.
Even today, existing technologies have significant drawbacks and only 20% of plastics worldwide are recycled compared to 80% of steel. It is therefore important to consider that recycling alone cannot be the solution for the plastic waste problem, and we must also prioritise reduction and reuse. However, like waste collection and management, engaging in recycling is better than not as it generally conserves energy, emissions and resources.
What are the current methods of recycling for plastics?
Mechanical
The most common form is mechanical recycling, in which plastic is sorted into various types, then washed, shredded, melted and re-extruded into pellets to manufacture new products. This method generally consumes less energy and emits less CO2 than producing virgin plastic. Whilst mechanical recycling is usually considered to be the most cost-effective method of recycling plastic, the problem is that the separation of different plastic streams is never perfect, and, because each stream is always likely to be contaminated with other types of plastic, food residues or dirt, the chemical properties of recycled pellets will be inferior to those of the virgin material. This causes ‘downcycling’, in which food-grade plastic is recycled into (say) car components and those into (say) garden furniture. Typically, virgin plastic will go through only three cycles before ending up in landfill or Energy from Waste (EfW).
Chemical and Biological
Chemical recycling goes one stage further. Techniques such as pyrolysis and gasification recycle plastic by heating to high temperatures in conditions of low or no oxygen, which degrades the plastic without combustion, producing an oil or gas that can be used to make virgin-quality plastic. Many different types of plastic can be processed simultaneously – including soft plastic, which can’t be recycled mechanically – which reduces the need for sorting. All this goes some way towards solving downcycling. However, chemical recycling is typically energy intensive, although an external renewable energy source could provide the necessary heat. There are encouraging developments in biological and chemical methods which claim to make PET (polyethylene terephthalate- a type of plastic commonly used in food and beverage packaging) recycling entirely circular; this is also being extended to other plastics, alongside upcycling approaches, that seek to apply plastic feedstocks as a source for chemicals, which is encouraging given that PET represents less than 10% of all plastics.
Organic
Other biological recycling methods include industrial composting or anaerobic digestion, which only applies to a limited set of plastics. While they are a promising way to deal with plastic waste, questions remain about what is left of this plastic and what impact these have once the composted matter is introduced into the soil biome. So, existing recycling technologies either fail to conserve molecules and avoid greenhouse gas (GHG) emissions for long or are energy-intensive and expensive.
What do the public think of recycling?
In the UK, public attitudes towards plastic recycling suggest we must deliver on public expectations of what good recycling might look like. The results of our 2022 YouGov survey suggest there is a desire for recycling to be more efficient, easier to understand or simpler to undertake, and most importantly, for recycling our plastic to be globally, socially and environmentally responsible. Almost 9 in 10 people (87%) think that, as a society, we should be looking into better ways to recycle. Just over 8 in 10 people (82%) think recycling should be completed in the UK, and we shouldn’t send our waste abroad. Almost 3 in 4 people (74%) admit that it is hard to understand exactly what plastic can or can’t be put in recycling bins.
So, why bother? What does the future look like?
Whilst recycling practices and infrastructure are still developing, it is still an essential step towards creating a greener future, as long as it is used in collaboration with reduction and reuse. As technology improves, engagement with recycling from the general public will be essential to its investment and successful delivery. At the University of Birmingham Plastics Network, we are passionate about finding solutions for an improved approach to plastics recycling in the UK. We are running a policy commission to gather evidence which will inform recommendations to the UK government in this area, among others, across the plastics lifecycle, taking into account environmental, social, economic and political impacts to ensure that future policy is well considered and avoids unintended consequences.
What can I do at home and in the workplace to make a difference?
At the University of Birmingham, there are a range of ways you can engage with recycling plastics and other materials on campus.
Recycle Now, one of the citizen-facing brands brought to you by the Waste & Resources Action Programme (WRAP), has produced a series of helpful guidelines for engaging with recycling; take a look!
To read more about our work on the plastics problem, and to see references for all figures in this article, please read our Call to Action report.