Polystyrene (PS) is one of the most widely used plastics in the world, and one of the least recycled. Used to make fruit and vegetable baskets, yoghurt pots, take-out boxes and various kinds of packaging, the petroleum-based plastic is responsible for generating significant greenhouse gas (GHG) emissions.

In 2016, the global annual polystyrene production reached 24 million tonnes and consumed 50 billion litres of oil; more than two per cent of global oil reserves, according to the World Energy Council. But if we are to limit global warming to a 2 degree Celsius increase, one-third of the world’s oil reserves will have to stay in the ground, according to a study published by science journal Nature in 2015.

In Ville d’Anjou in the suburbs of Montreal, Canada, the young company Polystyvert has been honing a technique that might be one of the most promising solutions yet for this issue. Its recycling process would reduce up to 83 per cent of the GHG emissions involved in virgin resin production.

“There’s only a handful of existing solutions for treating polystyrene,” said Andrée-Lise Méthot, founder and managing partner of Cycle Capital Management, a cleantech venture capital investment platform with offices in Canada, the US and China. “Their method involves dissolving the plastic in essential oils so it can be transported more easily.”

According to the most recent data from the Quebec government corporation for recovery, reuse and recycling, Recyc-Québec, 80 per cent of polystyrene waste generated by Quebec’s citizens is thrown into the trash can. Existing recycling options for polystyrene are limited — less than one-third of the waste stream gets treated and the activity is hardly profitable.

One of these options is compressing polystyrene into “logs” using a machine, but the approach has three main problems: transportation (this type of plastic occupies a lot of space), contamination (not all contaminants can be removed by hand) and versatility (the logs have limited uses). Another option, transforming solid plastic waste back to a liquid state at a very high temperature, offers more flexibility than compression and a greater variety of products can be made as a result, but it’s highly energy consuming.

The recycling technique developed by Polystyvert involves dissolving polystyrene in a concentrator filled with essential oils. The liquid is then poured through mesh, which catches any undissolved matter, and purified through flocculation – remaining contaminants form flakes that can be easily removed. Finally, an isolation liquid is added to separate 80 per cent of the essential oils. The resulting paste is washed to purify the polystyrene, which is then turned into 98 per cent pure transparent granules that can be reused to produce a vast variety of products.

The multinational corporation Sony had been the first to apply dissolving techniques to facilitate polystyrene recycling in the 1980s and ‘90s, but it eventually abandoned its experiments to focus on the electronics sector. “I studied Sony’s patent to reproduce their method,” said Solenne Brouart Gaillot, founder of Polystyvert, “but we didn’t succeed.” Finally, it was professor Roland Côté of the University of Quebec at Trois-Rivières (now vice-president of R&D at Polystyvert) who broke the deadlock in 2014. He came up with the new, patentable process that works on a beaker containing 20 gm of polystyrene.

Last May, the company secured a partnership with the French oil and gas giant Total, which could lead to a significant scale-up in the development of its technique. “Right now, the process developed by Polystyvert is the most advanced and the most attractive to a producer like us,” Alain Standaert, R&D manager at Total, said during an interview with Canada’s state television.

Polystyvert is still developing its business model, which for now is based on licensing fees. These grant access to the company’s technology and equipment, and the start-up receives royalties on the sale of each kg of recycled polystyrene. This model relies on the entire ecosystem surrounding polystyrene, which involves three main stakeholders: the technology provider (Polystyvert), the waste collector, and the processor (Total). While the first one generates income from selling its technology, the third one does so by meeting its clients’ demands.

“Companies like Danone ask Total and other petrochemical companies to supply them with recycled plastic, or else they will make their yoghurt pots from a different type of material,” said Brouart Gaillot. By 2020, all the virgin resin in the European Union will have to contain at least 20 per cent recycled material.

But waste collection is proving to be a challenge, as collectors and processors can’t seem to agree on waste prices – too low for one, too high for the other. Two possible ways forward exist. One could be to reduce the cost for collectors, by optimising the waste sorting system. The second would be to increase the prices of virgin material, which would incentivise processors to offer higher prices for waste material. In France, for instance, the government now imposes a 10 per cent surtax on containers that are entirely made of virgin plastic — an example that highlights how the fight against climate change depends both on technological innovation and behavioural change, whether voluntary or imposed.