Plastic waste is a global crisis.

So far, the world has looked at it as an unsightly menace to be removed, but Professor Thomas Maschmeyer has gone beyond that idea. His work challenges our perceptions of waste, by turning plastic into an asset that people would actively seek out to recycle because it can make them money.

“Of course, everyone is concerned about plastic waste, but the reality is, they also need to use plastic,” says Professor Maschmeyer from the University of Sydney's School of Chemistry. “Our recycling method reconciles those two ideas.”

Professor Maschmeyer created a chemical process where plastic waste can be turned into fuel, or used to make new plastic again, and again. It can also handle any kind of plastic, including the contaminated plastic that China recently stopped importing as it moves away from being the world’s largest waste recycler.

The chemical process

The recycling process is based on the catalytic hydrothermal reactor (Cat-HTR) platform, developed by Professor Maschmeyer and his colleagues at Licella. It was the starting point for what was then a startup company, Licella, which has been strongly supported by the University of Sydney.

Using water at high pressure and high temperature, Cat-HTR breaks plastics down to their smaller chemical components. The water prevents unwanted chemical reactions, then catalysts are used to make the components rearrange themselves into new forms:

Solids, like industrial waxes for the food and coatings industry

Heavy liquids, like oils/greases for lubrication purposes

Light liquids, like solvents and fuels such as diesel or petrol

Reactive gases, like ethylene, which can be used to make new plastics.

The process takes about 20 minutes with low energy usage and minimal greenhouse gas emissions.

As it converts plastic waste into usable products, the Cat-HTR process will also change peoples’ perceptions. “It monetises plastic waste,” says Professor Thomas Maschmeyer. “So it will be treated as a resource to be used rather than a liability to ignore.”

The good news is that this transformative advance has already moved well beyond the lab. In fact, the first Cat-HTR plant is currently being built in the north of England with ReNew ELP and will soon be converting up to 20,000 tonnes of waste plastic annually, with analogous plans taking shape in Australia through iQRenew.

By thinking beyond the accepted methods, Professor Maschmeyer and his colleagues are helping to clean up the world, one plastic bottle at a time.