The popularity of takeaway coffee has led to a surge in disposable cups, but the problem now is to work out how to recycle them effectively. Lou Reade reports
For somebody who lives an idyllic life in a riverside farmhouse, Hugh Fearnley-Whittingstall has a ‘lot of bees in his bonnet’. Recently, he has taken a short break from protesting about food waste, battery chickens and over-fishing to focus his ire on coffee cups – and the fact that only a tiny percentage of them are recycled.
By his estimate, 2.5bn paper coffee cups are thrown away in the UK every year – and only 0.25% of them are properly recycled, despite most cups being plastered with a ‘recyclable’ label.
The reason for the lack of recycling is the structure of the cups. They may look as if they’re made of paper or cardboard, but a thin layer of polyethylene on the inside – which ensures that the liquid does not soak through – makes all the difference. It’s this PE lining that makes the cup difficult to recycle.
One proposed solution is to make the lining from a biodegradable or compostable material – an approach that some cup makers are now investigating.
UK-based Biome Bioplastics makes compostable polymers from raw materials such as corn and potato starch. It has been working with cup manufacturers to incorporate its starch-based materials into cup linings – with some degree of success.
‘We’ve done work in the UK and Scandinavia, and have worked with several large coffee players and suppliers,’ says Paul Mines, the company’s CEO. ‘They’ve yet to adopt the technology – but it’s getting closer. They are still testing and trialling, to make sure that it works for them.’
If the plastic itself is compostable, it could be recyclable within the paper stream, he says, allowing the whole cup to be recycled in this way. Mines says that those companies that have run trials with the material are ‘comfortable’ with the amount of compostable plastic lining on the paper cup.
‘I can see it happening within two years, as it’s achievable using current technology,’ he says.
The issue is mainly one of processing, he says, to ensure that the coating can be applied to the cardboard at mass production speeds.
Aside from the cup itself, Biome has also been working on biodegradable lids.
‘A lot of work has gone into developing a compostable lid that can go into the paper recycling stream,’ he says.
There are already some lids on the market made from polylactic acid (PLA), which is well-established for biodegradable packaging; however, PLA is not very robust.
‘Its properties are quite brittle,’ says Mines. ‘The issue is to come up with a functional lid as good as polystyrene, but which can also be composted in the paper waste stream. That’s a significant objective.’
Developing a lid is more technically challenging than a coating, he says, because it will require a material that satisfies a number of competing criteria. ‘It’s quite a thick section that must retain its structural strength at 100°C while clipping over the cup,’ he says. ‘It must also be food-approved, and compost within three months.’
He says it is highly likely that coffee majors will want to develop both lids and linings that can be treated in the paper waste stream. But before then, there are other issues to address.
‘Another challenge in future will be that you’ll have a mixture of cups with recyclable linings, and those with a standard polyethylene lining,’ he says. ‘Not everybody will change over – and it will give the waste people an issue in terms of separation.’
The fact that the layer is very thin would make it hard to determine between these two types of cups.
However, Mines accepts that compostability can be a double-edged sword when it comes to recycling and waste. The notion can cause customers to do more – rather than less – littering, as they think compostable articles will simply dissolve harmlessly into the environment in a short time.
‘If people see a ‘seed’ logo on a cup, some of them think they can throw it in the hedgerow because it will biodegrade,’ says Mines. ‘It will biodegrade, but not in three months.’
This point is picked up in a recent report on Biodegradable Plastics & Marine Litter from the United Nations, which says that labelling a product as biodegradable may be seen to ‘remove responsibility from the individual’.
Send in reinforcement
Another approach to the paper cup problem, which is close to commercialisation, looks to use shredded coffee cups as a fibre reinforcement in new plastic products.
‘We specialise in separating and sorting materials, but recognise that sometimes it can’t be done economically,’ says Edward Kosior, director of consultancy Nextek. His estimate, which is some way short of Fearnley-Whittingstall’s, is that the UK uses around half a billion disposable cups every year, equivalent to more than 36,000t, which are either incinerated or sent to landfill. However, ‘that’s only a tiny percentage of all the material sent to landfill – which is in the millions of tonnes,’ he says.
Because it is not viable to separate the paper and plastic elements of the cup, the research has taken a different approach by using the ‘waste’ material for making a new product.
‘These are good raw materials – high quality fibre and polyethylene,’ he says.
Kosior and his co-researchers, including a team from Imperial College in London, UK, have developed a range of formulations for ‘paper plastic composites’. In one technical paper (doi:10.1016/j.wasman.2014.05.020), the researchers describe an optimised formulation comprising around 57% polypropylene – derived from waste electrical products – a 40% loading of shredded paper/polyethylene cups, and 3% of a coupling agent, maleic anhydride grafted polypropylene. The coupling agent acts as a ‘bridge’ between the two phases of the mixture. The 3% loading gave the best improvement in mechanical properties, said the researchers.
Kosior says that a number of other formulations have been created, some to the specific instructions of customers.
There are some constraints to using paper as a reinforcement, he says, such as its decomposition temperature of around 200°C. ‘This restricts the number of resins we can use,’ he says. ‘We also don’t want to destroy the fibre.’
The resultant plastic can be used to make ‘wood substitute’ products, such as pallets, skirting boards, decking or fence panels, using either injection moulding or extrusion. He says that a typical approach is for a company to use its own waste stream to make products that it needs – rather than buying new ones. ‘Because material is the main cost of any product, this will make the product cheaper,’ he says, citing a theoretical example of a company that generates waste cardboard tubes which could be shredded and used as reinforcements in ‘home made’ pallets.
Kosior adds that coffee companies are using this principle – turning waste coffee cups into ‘useful products’ – but declines to specify what the products are.
Bins from cups
This same principle has been used by Starbucks at its outlets in Brazil, the world’s leading coffee-producing country. In partnership with Brazilian petrochemicals giant Braskem, Starbucks is using the used cups – and other waste, including coffee grounds – to make in-store bins to collect more discarded cups.
These recycling bins are made from Braskem’s bio-based polyethylene – which is derived from sugar cane rather than petroleum – as well as waste coffee grounds and a filler made from recycled coffee cups.
The cups and the coffee grounds are washed and granulated, and then extruded with Braskem’s Bio-PE to create the bins – which have a delicate coffee aroma, due to the presence of the coffee grounds. The initiative has been adopted in a store in São Paulo, and there are plans to extend it further.
The partnership is one of Braskem’s Wecycle initiatives, in which the company tries to promote business solutions through plastic recycling. Interestingly, this particular project focuses on cup collection, because it is this factor – not technology, not compostability, and not even Hugh Fearnley-Whittingstall – that will prove most important.
US-based firm MicroGreen’s InCycle coffee cups – made from recycled PET water bottles – were used by customers including Alaska Airlines and Virgin America starting in 2013. The company raised an estimated $80m in equity funding and won a number of industry awards. In early 2014, for instance, it received $10m from two Native American tribes – allowing it to raise production to 2m cups per day.
However, while it was winning new customers, it was not turning enough profit and failing to make interest payments to its backers. One year later, its largest backer – The Confederated Tribes of the Grand Ronde – called in an $8m secured loan, which could not be repaid. MicroGreen closed in April 2015, with the loss of around 100 jobs.
Not all coffee cups are made from plastic-coated cardboard. There is also expandable polystyrene (EPS) foam, which has environmental issues of its own: because it has already been ‘foamed’, it is difficult to recycle.
Exact statistics are hard to find – and almost impossible to verify – but the US Environmental Protection Agency estimates that more than 25bn EPS cups are thrown away in the US every year. By contrast, the number of discarded cups is thought to be twice this amount, at 58bn/year.
In July 2015, New York City imposed a ban on the material. It wasn’t just cups that were affected, as EPS is used for many other things including the ubiquitous take-out boxes that keep food warm.
That, coupled with the difficulty of recycling the material because it has already been foamed and is hard to re-use, meant that its time was marked.
One all-plastic alternative to EPS is the Versalite cup from Berry Plastics. Versalite is made from polypropylene (PP), a commonly recycled plastic. A number of outlets have begun to switch away from EPS and start using Versalite, says the company.
At the company’s results presentation in July 2015, which coincided with the New York City ban on EPS, Berry’s CEO Jon Rich said: ‘Dunkin’ Donuts is now using Versalite cups in more than 500 New York City locations, and expanding its use to other cities and regions. Versalite cups were commercially introduced to new customers such as Cumberland Farms, Sheetz, and several other large chains.’