It is the one remaining piece of waste material that still largely gets chucked away by householders. In some respects mixed plastic remains the holy grail of UK recycling, the waste stream that because of its wide variety of polymer types continues to provide a major headache for recyclers, industry stakeholders and policy makers alike.

One million tonnes of the stuff – the pots, tubs, trays and plastic films that encase our food, toiletries and other household items (read: all domestic plastic packaging save bottles) – gets thrown away each year. At present a mere 26 per cent of UK local authorities have collection schemes in place for mixed plastic. And that
means that most of it still goes straight to landfill.

But recently things have been changing. The issue of how to deal with this stream became more prominent in 2009 when WRAP published a report into the feasibility of recycling mixed plastics in the UK. The study, which was based on trials that involved 26 different business and three materials recovery facilities (MRFs), concluded that mixed plastics recycling in the UK was ‘technically viable on a commercial scale’.

Of course being ‘technically viable’ does not mean that it is ‘currently possible’. The WRAP report gives a green light to councils to head out and collect mixed plastics, but the technical know-how is not currently matched by infrastructure to handle this waste stream. At the moment, the UK has only one dedicated mixed plastics washing and sorting plant, Biffa Polymers in Redcar, and it only takes the rigid fraction (see article on pp13-14), meaning the bulk of the material is headed for export and is at the mercy of demand fluctuations and rising transport costs.

It should also be pointed out that what we term as ‘mixed plastic’ covers a huge array of different materials. It’s a veritable alphabet soup of polymers (with an overabundance of ‘P’s): HDPE, PET, PP, PS, PE, PVC, and so on. At its most simple, though, there are two main types of mixed plastics: rigid (yoghurt pots, food trays, etc) and film (bread bags, crisp packets and so on). Film plastics are notoriously difficult to recycle because many are
multi-layered or even metallised (think crisp packets), and they are often heavily printed with volatile inks.

Both films and rigids also differ in the manner in which they are sorted, separated and processed. Films are sorted using mechanical means, like vacuum suction and manpower, whereas rigids tend to be sorted by near infrared technology.

The end markets for both types of plastic also differ widely. Rigids can be recycled (or, downcycled, if you’d rather) into plant pots or moulding for electrical components. Other than use (usually at low percentages) in further film applications, such as refuse sacks, end markets for films are very much in the development stage. “Generally speaking I don’t think anybody has yet got a sensible application for those”, says Bernard Chase, Purchasing Manager of Yorkshire-based plastic recyclers REGAIN Polymers (formerly LINPAC), which specialises in recycling rigid plastics. “Often they are just a contaminant to be got rid of wherever possible as far as recycling of rigids is concerned.”

All of which is well and good, but the consumer, faced with an abundance of polymer types (all confusingly identified by numbers inside recycling symbols, whether or not they’re recyclable) and ever-changing messages, can often get a bit muddled. Recently, the British Retail Consortium reached an agreement with the On Pack Recycling Label scheme to include film plastics with supermarket carrier bags in bring sites, a move that plastics recyclers have said will lead to more confusion and contamination.

And, as the amount of collected plastic bottles has increased – some 46 per cent of the UK total in 2009/10 – this has had a knock-on effect of also drawing in non-bottle rigids. “I would say even two or three years ago that the collection of [mixed plastics] was fairly nominal”, says Stuart Foster of plastic recycling charity Recoup. “But now it’s growing and growing. What we’re finding is that most of it is mixed in with the bottled material, which is why we’re seeing investment and development from some of the existing plastic reprocessors to accommodate it.

“But it’s also encouraged that mixed material to be sold to China, who can offer competitive market prices. Now, we don’t have an issue per se with the Chinese market particularly if people are following proper audit trails. But the general feeling around the industry is that, well, the Chinese market allows quality to slip sometimes.”

And this is a shame as so many reprocessors out there are crying out for high-quality material. Chris Dow, Managing Director of Closed Loop Recycling, recently noted: “When Closed Loop started out three years ago, good plastic bales were those with 95 per cent bottle content. Now, we’re receiving bales that contain less than 80 per cent bottle content.” Dow blames councils’ ‘chuck it all in’ approach, and fellow plastic bottle recyclers ECO Plastics have pointed out that councils, too, are suffering because of this attitude; the contamination means councils are receiving £40 less for every tonne of plastic they collect, a significant sum in these straightened times.

Mixed plastics reprocessors also have issues with contamination. “We get a particular stream, polypropylene,” says Chase, “and we can achieve at best 65 per cent out of a bale that has already been through a MRF and a PRF [plastics recovery facility]. So it’s been to three places by road and we’re chucking about 20 per cent of that back into landfill.”

According to Chase, the industry is “trying to sprint before it can even crawl. People who have set up plants to reprocess bottles have spent millions on their plants and their plants are grinding well below efficiency because the quality of what they were expecting to get was mixed bottles. Actually what they’re getting is now mixed plastics because the consumer has already jumped the gun thanks to WRAP saying ‘Ooh, yes, we are funding mixed plastics recycling.’ Now the householder just takes it as read that it’s mainstream technology so in it all goes.”

For others, though, contamination is not such a vexed issue. “We haven’t found it to be a problem, and certainly Biffa haven’t found it to be a problem at their new Redcar site”, says Gareth Boyle, Plastics Project Manager at WRAP. “Plastic is quite a resilient material really, and the process at the Redcar plant is geared up and quite robust to remove those contaminants. By the time it has gone through the optical sorters and through granulating it is a very pure stream.”

But in the wake of the WRAP report more local authorities are now looking to introduce a mixed plastics collection to the service. The question remains: does the UK have infrastructure to cope with mixed plastics recycling on a large scale? The opening of Biffa’s Redcar plant is a big step forward, and some other facilities, like Jayplas in Leicestershire and ECO Plastics, can handle at least some mixed plastics. What’s more, WRAP has put in place a Mixed Plastics Loan Fund, a scheme whereby projects with a proposed capacity of over 15,000 tonnes per annum can apply for loan funding.

Before the UK jumps in with both feet, Bernard Chase, for one, argues for more coherent thinking. “Just collecting our waste and shipping it off to China... Yeah, fine, it ticks a very blunt target, but it doesn’t deliver anything else to the UK economy. And yet we have customers crying out for more recycled material. But they have quality expectations, and a lot of the good, clean single streams we used to get have been lost effectively through the total waste management route.”

Yet is this any excuse for inertia? Boyle sees the current situation as “a classic chicken and egg. Local authorities want to see that there’s an end market for further material in order to commit to collecting it. And at the same time on the other side of the coin people who want to invest in the infrastructure want to see that there’s a secure supply coming through to justify the investment.

“But with the Biffa facility we’ve got the start of it. Others are interested and want to enter the market, local authorities want to collect more, householders want it. So although we’re not there yet, there’s a journey that’s already underway.”