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Ending the magical thinking on compostable packaging

Is switching to compostable packaging a solution for New Zealand’s plastic problem? Don’t get too excited too soon, warn experts.

Public understanding of waste management in New Zealand has often been defined by magical thinking. If you throw a coke bottle in a recycling bin, then it will be recycled, and it’s not your problem any more.

For plastic, that idea has been thoroughly demolished, ever since China decided to stop being where other people’s problems were sent. As a result, single use plastic is now piling up all over the world. For some, the latest simple solution is to turn to compostable packaging instead – imagine a world in which everything could be easily broken down and turned into something useful again! Unfortunately, and much like a rubbish bin itself, the deeper you dig into it, the murkier it gets.

It’s a problem of not just environmentalism, but also infrastructure and economics. A fundamental hurdle that compostable packaging comes up against is that commercial composters don’t necessarily want to take it. If consumers think that it’s simply a matter of having new bins put in place where they can throw compostable packaging, and, as with recycling, it’ll become someone else’s problem, they’re wrong. Commercial composters, like the name would suggest, produce compost for the market. Food and garden waste can be turned into high-quality compost full of useful nutrients, and a huge amount of it currently just goes to landfill. But the same can’t necessarily be said of compostable packaging. Just because something can be composted as a process, doesn’t mean that compost as a product is worth anything to anybody.

Paul Evans, the CEO of WasteMinz, says many people are looking at these problems from the perspective of consumers and manufacturers only, rather than from the perspective of a composter. He also raises the point that different materials compost at different rates using different processes, and facilities aren’t necessarily set up for packaging. “That’s where composters are saying they’re willing to take it under certain circumstances, and certain types of materials, if it works with their process. That’s one of the challenges around this – many of them aren’t suitable to take this sort of material.”

Evans says it needs to be thought about in a joined-up way – he says there’s a massive consumer demand for something that isn’t plastic, but often when brands look to jump to compostable packaging, they don’t take the technicalities into account. One composting facility is not necessarily the same as all the rest. Some only process green waste, and create garden mulch out of it. Others are certified organic. Others can take packaging, but only certain types. There’s a range of other factors that need to be taken into account, ranging from resource consents to whether a facility is near the coast – with the accompanying risk that material might be blown into the sea.

Biodegradable often just means it will break down – but break down into microplastics (Photo: Getty Images)

Contamination is also a huge concern for commercial composters. Think about an apple, for example. Perhaps it starts to go mouldy before there’s a chance to eat it, so it gets thrown into a compost bin whole. That should be fine, but what if there’s a plastic sticker on it? Now the entire batch of compost could end up being contaminated. This is also one of those areas where the terms biodegradable and compostable packaging don’t mean the same things at all. Biodegradable often just means it will break down – but break down into microplastics, rather than politely disappearing into the ether. That’s no good for soil, and it’s no good for compost either.

It’s something that ends up wasting a lot of time for staff at the Christchurch City Council’s Organics Plant. Contract supervisor Leon Austin says plastic is the most common and problematic contaminant received at the organic processing plant, with approximately 60 tonnes of plastic removed and sent to landfill each year. “It increases the risk of the compost we produce not being able to meet the quality standards required by our customers, and it requires additional equipment and processes on site to deal with it,” he says.

While the organisation tries to educate residents that plastic is not OK for the city’s green bins, Austin still has a hard slog getting the message out. He says there’s no level of plastic that can come in, because as a certified organic facility, its customers require it to maintain its contamination-free status. He also has concerns around confusion between biodegradable and compostable products – in particular those with untested plastics or resins. “Without these tests for proof, the threat of small plastic fragments and chemicals that can harm the soil and kill earth worms is real.”

That murky distinction between biodegradable and compostable is also a concern for Dr Olga Pantos, senior scientist at the Institute of Environmental Science and Research. “There is a frequent misuse of the word “biodegradable” when it comes to plastics. Something that is compostable and biodegradable will, under the correct conditions, fully break down by biological activity into carbon dioxide, water and biomass. However, ‘biodegradable’ is also being used to describe plastics that simply break down into smaller pieces (ie microplastics) quickly.”

She says there’s often confusion for consumers around this – even those who want to do the right thing find themselves misled by labelling that is hard to understand. 

Many products also shouldn’t really be made compostable in the first place, says Paul Evans. He cites the likes of compostable nappies, compostable pens, or even compostable shampoo bottles. “OK, so the bottle will break down, but then there’s going to be residual shampoo in there, with detergents. What does that mean for plant growth?” he asks.

Is a solution for everyone to set up a compost bin in their backyard? It’s another nice idea that doesn’t necessarily work in practice. James Calver from Ecoware, a compostable packaging manufacturer, says there’s a lack of education and common knowledge around what actually makes a home compost system function, particularly with regards to having the right nitrogen levels and temperatures. “Having a compost bin out the back doesn’t necessarily mean it’s going to work.” It’s technical and difficult, and many people don’t have the time to make it work. Ecoware makes a point of doing pickup for customers to avoid this situation. 

So does that mean that compostable packaging is entirely pointless? Not at all – there is absolutely a place for it, provided it’s done right. Events are an example of this. Picture a music festival where every bit of food sold comes on a compostable plate, with no plastic cutlery given out either. If that waste is then collected in a seperate container, decontaminated and taken to an appropriate facility, then it can be composted successfully, with no plastic ending up in a landfill. 

WasteMinz is aiming to bring more information into the public arena about what can and can’t be composted, and more importantly, where. There are dozens of places around the country that do some form of composting, but most don’t take packaging. So they’ve launched a website which will track those facilities around the country, and have committed to keeping it up to date as processors change their policies. But like with all other forms of waste management, the most important approach to get right is prevention – to not produce the waste in the first place.


The Spinoff’s food content is brought to you by Freedom Farms. They believe talking about food is nearly as much fun as eating it, and they’re excited to facilitate some good conversations around food provenance in Aotearoa New Zealand.

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