“Plastic’s fantastic…but we’re rubbish at recycling it…”
In a recent episode of BBC Radio 4’s new science documentary series Rare Earth, presenters Tom Heap, a science journalist, and physicist Dr Helen Czerski Look to the work of reseachers and innovators. Who’s in charge: us or plastic? wrestles with whether we can stem ‘the tidal wave of plastic pollution we’ve unleashed’, causing environmental, and health problems worldwide—and asks just how long these solutions might take.
At the UCL Plastic Waste Innovation Hub, “a fully kitted out lab with state of the art facilities to investigate and find new solutions to plastic waste issues”, Czerski and Heap spoke to P3EB’s Professor Mark Miodownik, who describes what exactly this “miracle material” actually is, why it has become something that we cannot seem to do without, and what might be done to close the cycle of plastic waste, now one of the world’s biggest pollutants.
“We’re looking at all different plastic waste issues. These issues are brought to us either by the government or by companies who fund our research, and we come up with solutions” Miodownik says. This is work that needs many perspectives. “That is important…you can’t solve those issues without bringing in chemists, biochemists, mechanical countries, material scientists, psychologists. We’re talking about behavior as well as economics, as well as the materials.”
“It’s a brilliant product. It really does the job very, very well. The materials innovation is amazing. But then what happens end of life? Have we given any thought to it?”
Asked by Czerski and Heap just why plastic recycling has been such a difficult problem to tackle, Miodownik responds, “We can do it. We just haven’t invested as a society in it.” By contrast with other high value industries that have been recyling their materials for hundreds of years—for example, steel, iron, gold, zinc, copper, in the plastic industry, he tells the programme, “we, I think: societies, governments, and the companies making them, have been basically saying, Oh, it doesn’t matter. We won’t really put any money in it, and it’s so cheap to make…why would we? So now that we’ve all woken up to the problem, we’re starting really from a very low base of technological prowess, but we can do it, and that’s what this lab’s about.”
The UCL Plastic Waste Innovation Hub is currently engaged with the recycling issues of products that many of us may not even realise contain plastics, but that create waste that is not just hugely challening, but a rapidly growing problem. They currently have, for example, “a big project on nappies…there’s a lot of plastic in that—by volume, up to 50% plastic. It’s a brilliant product. It really does the job very, very well. The materials innovation is amazing. But then what happens end of life? Have we given any thought to it?”
The answer to that question has been a firm no. More than 99% of the waste from not just nappies, but incontinence pads (which are “about to become a tsunami because of an aging population”), and period products “either ends up in the environment or incinerated. By the way, burning plastic is worse than burning coal in terms of CO2 emissions and pollution, so it’s not a good way to deal with climate change.”
These products are a good illustration of the problem of plastic waste separation for recycling. Within them, a real challenge the Hub is working on “is the super absorbent polymer, the thing that really sucks it all up. And that stuff no one knows how to recycle. P3EB’s Dr Luba Prout, Professor Helen Hailes, and Dr Jack Jeffries are designing ways to enzymes to take it apart molecularly and make monomers again. These are the building blocks of plastic, and then we’re going to take those monomers and build other plastics.”
Enzymes “are incredibly complex molecules that have to fold in a particular way to do the thing they have to do. But if you can get them to work”, Miodownik explains, “they can pick apart these polymers, bond by bond. They do it very slowly at the moment, because nature hasn’t evolved any ones that can do it fast. So what we’re doing is we’re genetically engineering them. Our chemists and biochemists are trying to find ways to speed them up. And that itself is a miracle of science, but it’s also the future.”
The process he describes might be compared to what happens in breweries, where different enzymes are used to speed up the conversion of barley into fermentable sugars. “We need to make it as fast as brewing beer. The future of recycling plastics could be not a mechanical thing that you see today, but more like a brewery. You put the plastics into a big container, put the enzymes in it, and they pick them apart in the same way that it produces alcohol.”
But instead of beer, this solution “is actually going to produce small molecules for precursors for plastics.” The aim is that those building-blocks will be widely adopted, so that they can take on a new life as innovative, high-value recycled products.
Listen to the full documentary here.