Compostables: rubbish or realistic?

Written by: David Burrows | Published:
Compostables are billed as a “practical solution” for food-contaminated disposable packaging that would otherwise have no quality recycling options

Compostable packaging looks good in theory, but is it ending up in the wrong place, or worse: doing more harm than good?

In February, BBC Wales ran the following headline: “Plant-based compostable plastics going to landfill.” Only one of the 13 councils contacted said it collects and composts these products.

The Welsh government’s response was particularly candid: "We have a long history of evidence-based environmental policy [2017/18 recycling rate: 62.7%] and we intend to continue this approach rather than putting in place piecemeal solutions to topical issues without considering whether they will work in the long term."

It isn’t just Wales that’s struggling with these materials. In Scotland, the government suggests compostable packaging is bleeding into every waste stream – residual, dry mixed recycling, garden and food waste – mainly because neither consumers nor businesses have a clue where it should go.

It’s a fair bet England and Northern Ireland have similar issues. In fact, the extended producer responsibility (EPR) consultation by Defra highlighted the concerns: compostables “can undermine mechanical recycling of conventional plastics” and even be a “contaminant” in the compostable waste streams if the plant can’t handle the material.

If they are a contaminant and the best treatment route is landfill or an incinerator, then you have to ask the question: why bother with compostables at all? Some businesses – paying a premium for these products – have already begun to regret their decision. And with every headline like the one above, doubts among consumers who have veered towards brands using these “sustainable” alternatives to plastic will creep in.

Those involved in promoting the benefits of compostables have a different take, of course. The bio-based products on the market (compostables aren’t always plant-based) have a smaller environmental impact, they argue.

The waste management sector has also been “slow to adapt” to new materials and, despite a 70-year headstart, has a pretty dismal record on recycling plastic packaging. “You cannot contaminate what you don't recycle,” says David Newman, MD at the Bio-based and Biodegradable Industries Association, which represents a number of compostable packaging manufacturers. “Plastic waste recycling is very limited.”

So are compostables a con? Or are they the subject of a witch-hunt by those with a desire to maintain the UK’s reliance on oil-based plastics and the status quo within the waste management system?

Finding an answer proved to be a Sisyphean task. After weeks of research and interviews, there were contradictions and competing ideas at every corner. However, this is a can of worms that needs opening up and shaking out, so here goes.

How much compostable packaging is out there?

Somewhere between 8,000 and 10,000 tonnes tends to be the ‘best guess’ but it could be as high as 20,000. Even at that level, compostables would represent just 1% of all plastic packaging. However, more accurate data is needed – not just how much, but where it ends up. Indeed, the compostables sector has been quick to throw numbers around to show how rubbish the recycling rate for plastic is (46%) but have no figures of their own to offer.

That’s because there is nowhere to send it, isn’t it?

Yes and no. Compostables are billed as a “practical solution” for food-contaminated disposable packaging that would otherwise have no quality recycling options and go to incineration or landfill.However, neither anaerobic digestion (AD) nor industrial composting sites – in general – are keen to take them. Yet.

In the government’s consultation on collections was this advice: “Until such time as all households have food waste collections and all anaerobic digestion plants can treat compostable plastic packaging, we would suggest that consumers are told to put this type of packaging in the residual waste bin.”

It’s a well-known fact that AD sites tend to pull out all the packaging before treatment – and this is unlikely to change. Some companies have successfully bolted in-vessel composting facilities onto their sites in order to process the “soup” of material and food residue that the de-packager scrapes away, but there is unlikely to be a rush to invest in expensive refits.

“The last thing I want to do is rebuild an AD plant for 10% of the feedstock when 90% of it is fine,” says Adam Read, external affairs director at Suez. “I’ll just pull it out and burn it.” Dramatically reducing contamination from conventional plastic would help, but whether that is possible depends on education and far better labelling.

How about the composters?

The UK has around 55 composting plants suitable for processing foodservice compostables and another 150 or so that could process compostable drinks cups, lids and stirrers (and this capacity could swell if England pushes ahead with mandatory food waste collections). The argument that the infrastructure isn’t there is a bit of a red herring. The real problem is that the sites don’t want this packaging.

First, the material can slow down the process, which squeezes margins. Some firms, most notablythe compostable packaging manufacturer Vegware, have been working closely with sites through the Organics Recycling Group (ORG) to help overcome some of the challenges. A big step last year was the agreement that certain compostables could also be taken with garden waste for treatment in windrow facilities.

Still, theindustry has to do better at working with sites to “ease their fears”, says Julia Schifter, VP of strategy analysis at Tipa, a company focused on compostables within the flexible packaging market. Better revenue from taking the materials would also help. Composters get a few pence per tonne through the current Packaging Recovery Note system because the process counts as “recovery” rather than “recycling” (and yet EU laws on packaging consider composting to be on a par with mechanical recycling).

The review of EPR, including PRNs, could offer an opportunity to tweak this, which would certainly stimulate an end market for compostables. Manufacturers of compostable packaging also seem happy to foot the extra bill – and they could do with the money in order to deal with the other major issue.

Contamination of organic waste has got much worse, according to Emily Nichols, technical manager at ORG. “Some local authorities say that if firms can’t deal with the levels of contamination then they shouldn’t bid for contracts.”

Sites are doing their best, but it’s not good enough, according to the Environment Agency, which has just threatened to get tough on plastic contamination found in compost spread to land. It’s impossible to tell what’s compostable packaging and what’s not, so more money will be spent on pulling everything out and sending it all to landfill or incinerators.

Is it bad to burn or bury compostables?

It’s not a terrible idea, at least compared to burning plastics, which is second only to coal in terms of carbon intensity. Still, these are sophisticated products in which millions has been invested to ensure they compost. That they do biodegrade may make landfilling a problem – depending on who you speak to.

The BBIA asserts that there is “no cause for concern” given that compostables remain inert in landfill. Mark Hilton, head of sustainable business at consultantcy Eunomia, says landfills present a wide variety of internal conditions and most compostable packaging is also likely to be wet, increasing the chance of biodegradation. “Paper isn’t considered inert in landfill so I can’t see why PLA [a compostable bioplastic derived from plant sugars] would be,” he says.

Hilton, who is conducting research on compostables for Wrap as part of the Plastics Pact, also notes that the compostable polymer itself contributes nothing in terms of nutrients when composted and hence this can’t be seen as ‘circular economy’ thinking. “Compostable polymers certainly have their place, but where possible we need to make recycling of conventional plastics more circular, not switch wholesale to something that will have a lesser benefit.”

Is it better to focus on recycling plastic packaging, then?

It depends. Research by the UK-based clear packaging producer Stäger involved lifecycle analysis of a number of bio-based and compostable plastics against PET and recycled PET. Using 60% recycled and 40% virgin PET came out top. However, a move to bio-based PET (non-compostable but fully recyclable) with 30% recycled content would be even better, should it become commercially viable.

“If it can be recycled it tends to make sense environmentally to do so,” says Adrian Higson from bioeconomy consultants NNFCC, who led the work. However, start to look at why some plastics aren’t recycled – it’s too contaminated with food, for example, or there are technical difficulties, as is the case with films – and the benefits of compostable packaging begin to stack up, he adds.

So there’s life in compostables yet?

Definitely. Most agree that compostables have a role, but whether it will be “piecemeal” as the Welsh government put it or as a ‘major player’ remains to be seen. The BBIA has forecast there could be 200,000 tonnes of compostable packaging on the market within 10 years – and the comparatively small companies involved all have big plans (and they have undoubtedly been buoyed by policies to expand food waste collections and a new bioeconomy strategy).

Tipa is infiltrating a flexible packaging market worth $25bn in the EU, while Biome Bioplastics CEO Paul Mines says enquiry rates in the UK have “gone through the roof”. Foodservice companies have led the charge towards compostables, but retailers are also ready to reconsider them after a 10-year hiatus, with Waitrose and Sainsbury’s already making significant moves.

The interest of the major supermarkets – which collectively turned their backs on compostables when they realised the infrastructure wasn’t there to justify the additional cost – has spooked the plastics sector, which wants to keep a lid on just how much of this stuff gets onto the market and then into the dry recycling stream.

Whether they are genuinely worried about contamination or it’s competition they fear is debatable (RWW approached Incpen and the British Plastics Federation for comment but neither responded). Tony Breton from bioplastics producer Novamont suggests they need not worry. “No-one is saying compostables are going to take over; this is about identifying where they make sense.” Doing that, it seems, is easier said than done.


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