The public wants to recycle all varieties of plastic, and WRAP has deemed mixed plastic recycling technically feasible, but what with its limited infrastructure, is the UK ready to open this messy can of worms? Will Simpson finds out

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.”