Thousands of tonnes of recyclable waste will instead become landfill, after South Australia's Environment Protection Authority (EPA) was advised it was too degraded to salvage.

Key points: Victorian company SKM entered liquidation last year, leaving waste in temporary storage

Victorian company SKM entered liquidation last year, leaving waste in temporary storage Almost 400 shipping containers in Adelaide are being used to store recyclable material

Almost 400 shipping containers in Adelaide are being used to store recyclable material That will be sent to a dump north of the city after being deemed unsalvageable

The material was collected and stored inside almost 400 shipping containers for more than two years at Wingfield and Lonsdale by Victorian company SKM Recycling, with the intention for it to be sent to China.

But the company collapsed last year, after China restricted its Australian waste imports, under its so-called National Sword policy.

The SA Government has confirmed material weighing more than 10,000 tonnes — or 10 million kilograms — which had been gathered from household kerbside recycling bins would be taken to a dump at Inkerman, near Dublin, north of Adelaide.

"SKM had an unusual model for South Australia in that they took all of the waste from the yellow bins and compressed it into bales at a strong rate of compression," EPA chief executive Peter Dolan said.

"Other companies don't compress the bales as much. They sort it into different component parts."

As part of SKM's business practice, waste was transported to Victoria and then shipped to China, Mr Dolan said.

"Those bales with everything that was in the yellow bin, including contamination, have been sitting in shipping containers in the heat for more than two years," he said.

"It's degraded, there's contamination in those containers, be it food scraps or whatever, and that's now deteriorated to a state where it's not possible to process."

'Not suitable for recovery', Environment Minister says

Environment Minister David Speirs said the waste equated to more than one per cent of the total amount that goes to landfill across metropolitan Adelaide each year.

"All avenues to recycle the materials were explored, but unfortunately there were no other viable options in the immediate future," Mr Speirs said in a statement.

"An independent waste expert examined the material and determined with current South Australian technology, the material is not suitable for recovery at this time due to degradation.

"Leaving the materials stored at the Wingfield and Lonsdale sites is also unacceptable as they will continue to deteriorate."

Adelaide councils contracted with SKM have now signed up with other waste management companies, and Cleanaway acquired SKM's assets in October 2019.

Recyclable materials from liquidated company SKM Recycling have been stockpiled across the country. ( Supplied: EPA )

The State Government said sending the material to landfill required an exemption under the state's environmental protection laws, but would be exempt from the Solid Waste Levy.

However, Mr Speirs said he hoped technological advances would eventually "allow these materials to reprocessed".

"Inkerman landfill has the capacity to receive and store the material in a separate part of the existing landfill cell until such time the infrastructure is available in South Australia to process the materials," he said.

"This will also allow the local owners of the shipping containers — who have not been paid rent for several years — to take possession of their property."

More than 30 Victorian councils were forced to send their recycling to landfill after SKM Recycling refused to take any more kerbside waste.