Plastic composter changes Raglan’s recycling

by Ellie Jay

A Raglan zero waste scheme is discovering plastics placed in its commercial composter aren’t always as compostable as they claim to be.

A lack of regulation around product packaging means consumers are being duped into buying things which aren’t nearly as green as they seem, say waste management companies.

The number of different symbols on products and a lack of clarity over terms like “biodegradable” and “compostable” has meant that without the infrastructure in place to sort or process these products, a lot has ended up in landfill.

One enterprise trying to tackle this problem is Xtreme Zero Waste, a Raglan community enterprise that has started a trial of compostable plastics in its commercial composter.

Everything the town’s 5000 inhabitants throw away is taken here. At the moment they divert 75 percent of waste from landfill and are hoping the composter will help them divert another 19 percent.

“We’ve become plastic addicts,” the company’s organics team leader Liz Stanway said.

“With China saying we don’t want to have the world’s recycled plastic that we really need to look at how we use plastic packaging.”

When RNZ visited, plastic bottle caps, single use bags and fruit stickers were still whole and contaminating compost even six weeks into the composting process.

The composting unit is a concrete trough 40 metres long and 4 metres high with a sliding roof. When it rolls back you can see piles of food and garden waste in various stages of composting. Each pile is a different week’s worth of the town’s waste.

Amanda Moxey is a researcher looking at single use plastics. She is adding plastic products to the compost that claim to be “certified compostable” to see if they do break down, as advertised.

The trials involve plastic certified to international composting certifications and the initial results were promising.

New Zealand does not have a certification process of its own.

But Ms Moxey said this was not a problem; international standards were stringent enough.

However, labelling products did need to become clearer, she said.

“We need to adopt some form of labelling like we have for recycling that would have a very clear logo,” Ms Moxey said.

Most products that claimed to be compostable were actually only compostable in commercial facilities, she said.

Without proper processing, compostable plastic items most likely ended up in Landfill.

After the 12-week process the final compost product looks just like freshly dug earth, with no signs of plastic or the food waste.

There are plans to scale up the composting machine and the design can be replicated across the country.

Despite this, Ms Stanway warned against thinking certified compostable plastic as a silver bullet.

“I look in the supermarket shelves and think, ‘If all of that was compostable what would the impact be?’ The impact would be the mountains of plastic we see on TV not being able to go to China would suddenly become a compostable challenge.”