Two new technologies could, according to their creators, recycle all plastic waste into materials that could be used to create high-quality new plastics or fuel.
That could revolutionize the world's recycling system for plastic wastes, which has been staggering since China stopped accepting all but the cleanest plastic in late 2017. (You can read about the current plastic recycling crisis here.)
Even before that blow, we managed to recycle only a fraction of the plastic we discard. In 2015, according to Chalmers University of Technology in Sweden, only 14% of the world's plastic waste was collected for recycling. Just 10% of the world's waste was recycled into new plastics, mostly of lower quality, and 4% was lost in the recycling process.
Chalmers researchers think they can dramatically increase those numbers. They have developed an efficient process for breaking down any kind of plastic into gases that can be transformed into new, virgin-quality plastic.
The process involves high-temperature steam and is similar to the "cracking" of fossil fuels into simple molecules that creates the building blocks for plastics in the first place. The researchers describe their findings—in great detail—in a new, freely available article in the journal Sustainable Materials and Technologies.
"We should not forget that plastic is a fantastic material," said Henrik Thunman, lead author of the article, as quoted in a Chalmers news release. "It gives us products that we could otherwise only dream of. The problem is that it is manufactured at such low cost that it has been cheaper to produce new plastics from oil and fossil gas than from reusing plastic waste."
Thunman and his colleagues are aiming for a truly circular system, where plastic is created, used, and then at the end of its useful life processed into raw materials for creating new plastic products.
"Circular use would help give used plastics a true value, and thus an economic impetus for collecting it anywhere on Earth," Thunman said. "In turn, this would help minimize release of plastic into nature and create a market for collection of plastic that has already polluted the natural environment.
"We have been able to demonstrate the proposed method at a scale where we turn 200 kilograms [441 pounds] of plastic waste an hour into a useful gas mixture," Thunman said. "That can then be recycled at the molecular level to become new plastic materials of virgin quality."
The goal is to incorporate the new technology into plastic factories. Instead of passing through recycling centers, plastic waste would go directly to the factories, which would handle it as just another raw material for creating their products.
A US company called Renewlogy has put its own technology for dealing with plastic waste into the field in the US and Canada. As with Chalmers, it can handle any kind of plastic.
Renewlogy grew out of a class project at the Massachusetts Institute of Technology. It launched in 2011 as a classic garage startup—literally. Co-founder and CTO Benjamin Coates borrowed his brother's garage to build the company's first prototype.
The technology uses a catalyst to degrade long carbon chains. Of the resulting shorter chains, 10 to 25% become hydrocarbon gas that Renewlogy uses to heat the system; 5% turn into char, an inert substance that may have some uses as a soil amendment but at a minimum sequesters carbon rather than allowing it to escape into the atmosphere.
The remaining 70%-plus of the shorter chains become feedstock for diesel fuel, virgin plastic, and other petrochemical products.
In 2014, the company began running a large-scale demonstration plant in Salt Lake City, Utah, where it is based. In 2018, it added a plant at Chester in the Canadian province of Nova Scotia. The plant processes 10 tons of plastic a day. Other facilities and initiatives are under way or planned.
"We use chemistry instead of mechanical processes to take plastic back down to its basic molecular form and make new products out of it," says founder and CEO Priyanka Bakaya in a video on the Renewlogy website.
"30 years from now, we'll be looking back at this moment in time and just realizing how foolish it was to be putting all this plastic into the landfill. We might in fact be mining landfills and taking all the plastic out because we're going to realize how much value the material has."