FEATURE: E&T MAGAZINE – Carving out a new plastics economy

As leaders finally grasp the gravity of the plastic pollution problem, new efforts are being made to build a more sustainable future for this versatile but pervasive commodity, including cutting-edge alternatives and engineering innovations in waste management and processing.

The world’s plastic waste problem has reached a crescendo. The estimates are stark: over the next 20 years production is expected to double, creating the risk that, if nothing is done, the roughly 14 million tonnes leaking into the ocean each year will grow twofold.

These stark statistics were surely at the forefront of the minds of the 173 country reps as they came together to pledge to develop a historic and legally binding global treaty addressing the full lifecycle of plastics. The resolution, agreed at the UN environment assembly in Nairobi, Kenya, in February, will see a plan hashed out over two years to end plastic pollution, including provisions for financial and technical support.

“It’s impossible to overstate the importance of this treaty,” says Yoni Shiran, partner at SYSTEMIQ, a ‘think-and-do’ tank, and co-author of a new report, ‘ReShaping Plastics’, on how to achieve a climate-neutral plastic system. “If it’s even half decent, it can be a game changer for the global plastic system [and] bring alignment on definitions and resources at a very different level.”

So far, the plastics debate has felt “dysfunctional” with different camps making noise but no real progress, he adds, but now it’s evident how “critical” the topic is currently perceived “when even a global pandemic and a war in Europe has failed to derail global collaboration on the issue”.

According to ‘ReShaping Plastics’ and another landmark study from the US, ‘Reckoning with the US Role in Global Ocean Plastic Waste’ – commissioned by bipartisan legislators and published in December, and which its chair, Monterey Bay Aquarium chief conservation and science officer Margaret Spring, says pushed the US to participate in the global treaty – the solutions are known and the technologies are largely available. If both were acted on and invested in in a co-ordinated manner, a new plastics economy could be achieved in-line with global climate change targets.

Recycling is a high priority. The flow of plastics could be reduced by 80 per cent with existing waste management and recycling technology, according to Shiran’s report. Yet most recycling systems are insufficient or overly complex; so much so that approximately seven billion of the estimated 9.2 billion tonnes of plastics produced between 1950 and 2017 are now waste.

Mechanical recycling, whereby plastic is physically broken down but remains chemically unaltered, is most common but it has its limitations. It can’t handle multi-layer plastics and is greatly impacted by design.

Chemical recycling is the alternative. This process uses chemistry to essentially reverse manufactured products back to their original components. It can tackle flexible and multi-layer plastics and even composites like glass fibre, as well as food packaging that doesn’t meet the food safety and hygiene requirements for mechanical recycling.

The technology is rarely used in Europe and the US, but a form of chemical recycling known as pyrolysis has been active in Asia for 20 years, says Thierry Sanders, director of waste footprint solutions company Circular Action BV. It’s used largely to convert rubber tyres to oil, and plastic to fuel via a heating process (400°C and higher) that breaks down the solid waste to separate the gas, the oil – crude, later refined into diesel at a 55 per cent to 75 per cent conversion rate – and solid waste, such as carbon wax, which can be used to make asphalt.

Sanders says the technology is “wonderful” for lower-value plastics but has a bad reputation because it’s difficult to build well. “Many DIY ‘engineers’ built their own pyrolysis machines with leaks, allowing oxygen to enter during the heating process, which causes dioxins to be emitted that are very dangerous and carcinogenic,” he explains. “But most modern and industrially built machines meet EU standards.”