“Massive amounts” of plastic contamination is getting into food and garden waste through user error and misleading “biodegradable” labelling, waste industry experts have warned.
Leading figures at some of Australia’s largest waste companies are calling for the government to standardise certification of compostable products, as many bin liners, compostable coffee cups and other material labelled “compostable” or “biodegradable” do not break down into organic matter.
The warnings come as states across the country are introducing food and organic waste collection programs in households in an attempt to halve the amount of food waste that ends up in landfill by 2030. In NSW, councils will be required to collect food and organic waste from all households by 2030.
“[There is a] massive amount of plastic that ends up in Fogo [food organics and garden organics] bins … [and] non-biodegradable items that wrongly claim to be compostable,” said Richard Kirkman, CEO and managing director of Veolia ANZ.
“These materials aren’t organic and don’t naturally decompose into the ground. Instead, they just contaminate what would otherwise be high-quality compost from genuine Fogo.” Much of the food and garden waste processed in Australia’s waste sector is turned into compost to be used in agriculture.
Confusion among consumers about the labelling of different products complicated the matter, said Kirkman. According to the Australian Standards for commercial composting, “compostable” products must disintegrate after 12 weeks and completely biodegrade after six months in a dedicated composting facility.
“Biodegradable” products are able to break down into elements found in nature, but not in a specified timeframe, which means the biodegradation process could take years.
“Not all liners on the market meet these standards,” said Kirkman. “Australians want to do the right thing, but it is virtually impossible to tell which caddy liners should be used. In fact, some liners remain fully intact after 16 weeks of accelerated composting and we have no option but to remove them by hand.”
Kirkman called the “contamination caused by ‘compostable’ bags and kitchen liners” used in Fogo bins “a nightmare for the industry”.
Ash Turner, state manager for resource recovery at Cleanaway, says that many of the kitchen liners sold at the supermarket are not compostable and will break down into microplastics that are then ploughed into the soil along with the compost.
“So they’ll say ‘biodegradable compost liner’ … but they’re not necessarily biodegradable,” he says. They do break down, he says, but adds: “Do they compost and break down into an organic? No, they don’t.”
Research by Veolia from earlier this year found that 72% of those surveyed thought compostable single-use coffee cups could be recycled in the yellow bin and 58% thought biodegradable plastic bags could be recycled, when Veolia advises that both items should only be placed in red bins and should end up in landfill.
On top of this, there were challenges around misleading labelling.
In 2023, researchers from the Institute for Sustainable Futures analysed 26 bioplastic products sold in Australia and produced by 14 companies, including plastic bags, coffee pods, postage backs and balloons.
The research found that nearly one-third of sustainability claims about the products were potentially misleading, including that not all that claimed to be compostable were certified to the Australian Standards.
Others used the term “biodegradable” for products that are not compostable and may take many years to biodegrade.
Both Kirkman and Turner have said they would like to see the Environment Protection Agency take steps to make it easier for consumers to buy bags they can be confident will compost, and enable those working in the plants to pull non-compostable bags out of the processing lines.
“We’re working with the EPA,” said Turner. “We’ve asked … that compostable bags be certified in some ridiculous colour … so if you want to make a compostable bag, you have to get certified and you’ve got to make it that colour, so either the guys on the line or our optical sorting equipment can be sure [it is compostable] and everything else comes out.”
Kirkman said: “If Australia was to go down the route of a single, easily identifiable caddy liner, that was certified, council-issued and built to a single national standard, that would be world-beating.”
But Gayle Sloan, CEO of Waste Management Resource Recovery Australia, goes further, advocating for no bin liners at all, saying the simplest solution is to have people put food waste into their kitchen caddy and take that straight to their kerbside bin each day.
“Bags complicate it,” she said. “It’s complicated for the consumer because you’re not sure if the bag is what it says it is … We’re creating waste with the liner. It’s one less piece of material that we have to use.”
