The chemical cure?

The final piece of the recycling jigsaw, or a toxic pseudo-solution? David Burrows reports on chemical recycling

Most recycling in the UK is 'mechanical'. The material is collected, cleaned and then chopped, shredded or melted into recyclates that can be turned into new products. The process is great for 'pure' plastic packaging such as PET and HDPE. It's also surprisingly low tech. However, it comes unstuck when there is contamination, or if there's a complex mix of different materials – and the problem is, it's composite packaging that has flooded the market during the past few years. More than two thirds of plastic waste generated in the UK is 'difficult to recycle', and of the third collected for recycling, only 9% is recycled domestically, according to the think-tank Green Alliance.

The easiest and cheapest way to deal with hard-to-recycle stuff is to bale it up and ship it abroad – or simply bury or burn it. The door to the first option is closing fast thanks to import bans in places such as China and Malaysia, while the other two are a waste of resources. “We recycle less plastic than any other commodity material – scarcely 7% overall,“ notes Susan Freinkel in her book Plastic: A Toxic Love Story. “We're burying the same kinds of energy-dense molecules we spend a fortune to pump from the ground.“

What if we could process this mixed or contaminated plastic waste – break it down into building blocks for new products, including plastics? What if we could do this over and over again so that virtually no plastic ends up in landfill or incinerators?

Game changer

This is the potential being touted by supporters of chemical or 'non-mechanical' recycling, a technology that Daniele Ferrari, president at the European Chemical Industry Council, calls a “game changer“. “Scaling up this technology will make Europe a global leader in circular economy solutions,“ he says. Sarah Bradbury, director of quality at Tesco, said in April this year that chemical recycling could be “the final piece of the jigsaw for the UK plastic recycling industry“. The supermarket had just launched a trial at 10 stores to collect unrecyclable plastic, which would be chemically recycled back into Plaxx, a low-sulphur hydrocarbon that can be used to produce new plastics.

The same technology is being used at a site in Perth, Scotland that will run mechanical and chemical recycling side by side to capture and process all plastic – not just packaging, but broken biros, mistreated toys and even traffic cones. “You name it, and if it's plastic we'll be able to take it,“ John Ferguson, director of Eco ideaM and head of strategy at the Binn Ecopark, told me during a visit last year.

The technology being used at the Binn Ecopark is pyrolysis, the thermal breakdown of plastic. This is just one of the technologies that fall under the umbrella of chemical recycling technologies. Others include: gasification, which involves partial combustion to produce synthesis gas; chemical depolymerisation, using chemicals to break a polymer down into its monomers or intermediate units; and dissolution, in which polymers are dissolved in a solvent so they can be separated from any contamination before being precipitated back out and re-used. Each of these technologies involves varying degrees of potential, cost and environmental impact – which means we can't talk about all of them in the same breath.

Serious concerns

Depolymerisation, for example, can have high energy demands, while the solvents used can be “damaging to the environment if not managed properly“, according to a report published by Wrap in October ('Non-mechanical recycling of plastics'). Some NGOs have claimed that gasification and pyrolysis have a failed track record due to inefficiency, emissions pollution and environmental impact. Greenpeace has “serious concerns about emissions of hazardous chemicals and their intensive use of energy“.

There is not much information regarding chemical recycling's environmental performance. Defra has said very little, with its 146-page resources and waste strategy simply noting that “it is important to consider the overall sustainability of the proposed process“. But we don't know if chemical recycling in its different guises will offer a lower environmental footprint than producing virgin polymer from crude oil. As Wrap's report put it, there is “a real possibility that from [a lifecycle assessment] perspective, an approach of making packaging from virgin polymer and mechanically recycling waste polymers into both packaging and non-packaging applications has a lower impact than non-mechanical recycling“. It's worth noting that the report was written by a firm with a vested interest in mechanical recycling. Nonetheless, it's pretty clear that more research is needed.

The other area of ambiguity is whether these technologies are really 'recycling'. The EU doesn't currently have agreed definitions for these technologies as a group. This has already led to greenwashing, according to Greenpeace, and “invites confusion“ according to Zero Waste Europe. Some companies are said to be deliberately conflating plastic-to-plastic technology with plastic-to-fuel approaches. Surely a process that turns plastic into fuel can't be called 'recycling'? “Turning plastic into fuel does not reduce the demand for virgin plastic, meaning that new plastic needs to be produced out of fossil sources,“ said Zero Waste Europe in its August report 'El Dorado of chemical recycling'.

Grey areas

The technology could well live or die by its outputs: that is, whether they are new polymers for plastic or have other uses, such as fuel or wax. Wrap's report offered this simple takeaway: “Without producing new polymer, the outputs should be considered recovery, and there is effectively little benefit over incineration of the plastic.“ But there are grey areas.

What about processes that produce plastic and fuel? Wrap's report suggests solvent recycling and depolymerisation then re-polymerisation of PET are 'recycling', but pyrolysis could be a harder sell given that the process also produces gas that is burned to provide energy to the process (which could be defined as recovery, not recycling). Until this is cleared up, we don't know if chemical recycling facilities will benefit from any new packaging recovery note schemes, or if their output will qualify as 'recycled'. Some of the tech is only at pilot stage, but the next five to 10 years are critical.

Won't these miracle processes just perpetuate demand for single-use, hard-to-recycle plastic? Greenpeace thinks so, stating that they are “undermining plastic reduction, the development of sustainable alternatives or innovations, and the incentives to phase out non-recyclable plastics“. It's a fair point: a technology that simply takes unrecyclable plastic and turns it into fuel undermines the circular economy and decarbonisation agendas. However, one that turns plastic back into plastic could be valuable.

The aim should be to keep the carbon in the plastic, rather than release it into the environment. Some of the new tech might just be able to do that, and the businesses built on hard-to-recycle plastics are excited by the idea – chemical recycling could help them deal with poor-quality plastic waste that can't be mechanically recycled. It's also a distraction from the tougher nut to crack: reduction of single-use packaging and rollout of reuse and refill schemes. Indeed, if hard-to-recycle plastic can be chemically recycled, demand for it remains locked in.

David Burrows is a freelance journalist