Southern Cross University Transforms Trash into Treasure

A house of brick may outlast a house of straw or sticks, but what about a house of plastic? Southern Cross University is working with local industry to lay the foundation for innovative, affordable housing, while keeping plastic out of landfill.

It's an issue that commands urgent attention. Across the globe, one million plastic bottles are purchased every minute and every year around 300 million tonnes of plastic waste are disposed of in landfills or released into the environment. It's a growing, global problem.

At Southern Cross University, researchers specialising in circular economy are forging new solutions through industry partnerships that flip the conventional approach to waste.

"The idea is that there is no waste, just different materials with different purposes. By unlocking the value of a material from one phase of use to another, it enables a model for commercially sustainable and regenerative resource use and re-use," said the University's Professor Andrew Rose.

This is the core principle behind Southern Cross University's Northern Rivers Regional Circular Economy Accelerator (ReCirculator), a $2 million program funded by the Australian government.

ReCirculator positions the University as an information broker, connecting businesses with cutting-edge technology to save costs, improve productivity and adopt circular economy principles. The University helps businesses identify the composition of their waste streams and any materials that can be recovered from it and finds solutions to waste reuse and recovery.

One of these businesses is Studio Kite, a professional prop and model-making company, which is looking to employ its giant 3D printer to produce housing. A prototype that can be easily transported and constructed is already well underway.

It's a timely endeavour, as Australia faces a critical housing shortage with the national vacancy rate hitting a record low of 0.7 per cent in February 2024.

"We have access to lots of different plastic material that's currently waste. And if that can instead be used to create these 3D-printed materials then that's a real win for the regional circular economy.

"Where we fit in with the circular economy is substituting the kinds of virgin plastics you might normally use with recycled plastic materials," Professor Rose said.

For Studio Kite Director Steve Rosewell, teaming up with Southern Cross University has enabled the company to source local plastic waste rather than transporting it from other regions. The University is also testing the structural integrity of the 32 metre-square (344 square-foot) 3D-printed homes – to make sure you can't blow the house down.

"We are working out how well the materials perform, not just with structural integrity but also how long it will last over the years," Mr Rosewell said.

"Coming from a theatrical and props building process and sculpting background, we wanted to perfect the building system but also make them attractive. We don't have to do square boxes; we can do interesting shapes. Everyone says they are really spacious; that is because there are no corners."

Thinking outside the box for plastic reuse

Diverting plastic from landfill is a major challenge for Australia.

"Australia was sending a lot of plastic waste overseas, especially to China. China then changed its policy regarding accepting plastics from other countries so the waste has just been stockpiled in Australia. There are warehouses all over Australia filled with piles of plastic," said Southern Cross University's Professor Dirk Erler, Chief Investigator for ReCirculator.

Solutions to the plastic waste problem are firmly in the sights of Southern Cross University's ZeroWaste Research Cluster, that draws together expertise in geochemistry, environmental science, engineering, business and education.

There are a number of projects in the pipeline.

"We have a major collaboration underway with Plastics Pirate which involves pyrolysis, which is heating the plastic in different amounts of oxygen. We can turn that plastic then into a fuel source, so back into a diesel product.

"The fuel can then be used to run machinery such as cars and tractors," Said Professor Erler.

Another project involves using plastics to make an aggregate as a replacement for traditional concrete. "It's much lighter and has better thermal insulation properties. We make these concretes and test their structural integrity," said Professor Erler.

The concrete aggregate project is in partnership with CRDC Global, a global building materials company.

"We are working with industry to develop and test technologies. We've embraced the fact that we want to broker technologies and partner with industries. We're not going it alone. This is a much bigger picture," Professor Erler says.

Southern Cross is ranked in the top 400 universities for Earth Sciences in the Global Rankings of Academic Subjects (Shanghai Rankings) 2023 as well as top 450 for Environmental Sciences in the QS World University Rankings 2024.