An Adelaide manufacturing company believes it can form part of the solution to the country’s plastic waste crisis by converting discarded plastics into lightweight structures, including bridges and jetties.

Sustainable Infrastructure Systems has spent four years of research and development with The University of Adelaide on developing its technology, which blends soft plastics such as shopping bags, plastic film, and food wrappers with a proprietary resin-like material to produce prefabricated panels.

The company claims the high-strength composite panels are the first in the world to be manufactured using mixed soft plastics waste, providing a structural strength on par with concrete, delivering an up to 48 percent reduction in embodied carbon when compared to a concrete panel, and lasting well beyond 100 years.

The first project to feature SIS’s technology is a pedestrian bridge to be installed later this month at the Newenham housing estate in Mount Barker in the Adelaide Hills.

It’s a partnership with local developer Burke Urban and the Mount Barker District Council.

The bridge measures 7.5m by 3.4m and contains the equivalent of 29 standard 240-litre kerbside recycling bins of soft plastics.

SIS managing director Nick Wotton, who founded the company in 2012, said that while recycled plastics had been used in the manufacture of structural building materials for decades, his company’s technology was the first to incorporate unprocessed, mixed, post-consumer soft plastics into structural panels.

“There are potentially limitless applications for our panels in transforming everyday rubbish into structures with huge benefits for our clients, communities, and the environment,” he said.

“For over 13 years, SIS’s aspiration has been that, ultimately, talking about sustainability will become superfluous, because it will be the expected.

“Our structural panels provide clients with a genuine reduction in embodied carbon and will be increasingly attractive as more infrastructure contracts are requiring companies to demonstrate how they will reduce embodied carbon across ­projects.”

A significant portion of the soft plastics used in panels made by SIS has been sourced from waste stockpiled following the collapse of the REDcycle soft plastics scheme in 2022.

State and federal governments are aiming to lift the rate of plastic recycling in Australia following the REDcycle scandal, where consumers were promised soft plastics would be recycled, but instead, 12,000 ­tonnes of plastic was stockpiled in warehouses across the country.

The federal government’s National Plastics plan is targeting 70 per cent recycling rates by 2025.

Mr Wotton believes SIS’ technology could provide a scalable solution to government and industry efforts to find alternative sustainable uses for plastic waste.