How do you solve a problem like plastics recycling?

It's lovely for people to think, as they are putting out their recycling or visiting a bring site, that all their plastic bottles will be given a second shot at life as a cosy fleece blanket or a sturdy picnic table. But people rarely stop to consider all that must go into effecting such drastic metamorphoses. These changes do not take place of their own accord, but require a great deal of planning and effort on the part of recycling organisations.

According to the 'Recovered Plastics Market Situation' report, published by the Waste and Resources Action Programme (WRAP), plastics recycling lags behind that of other materials, such as paper and glass. This is because of "the relative difficulty of collecting, sorting and processing plastics, due to their low density, the likelihood of contamination (particularly for plastics recovered from the municipal waste stream) and the wide range of polymer types".

Plastics recycling is very popular with the public, however, and 434 plastic bottle recycling schemes have already been set up across the UK, with more underway. While creating their schemes, recycling professionals must consider what kinds of plastics they will collect, how they will collect them, and what they will do to ensure quality and deal with contamination.

Bottles are by far the most popular form of plastic to recycle. Drinks bottles are generally made from polyethylene terephthalate (PET) and milk bottles from high-density polyethylene (HDPE), both of which have established reliable reprocessing markets and, if uncontaminated, command a high value: in January 2008, a tonne of clear PET fetched between £125 and £170, while a tonne of mixed HDPE yielded between £170 and £230. Mixed plastics made of lower quality polymer blends, including yoghurt pots and margarine tubs, are a bit more of a challenge, since a reliable market for them does not exist in the UK and they are less lucrative, bringing in anything between £70 and £150 per tonne.

Collection methods and transportation are also issues when it comes to collecting plastics, because they are high in volume, but low in weight. Many recycling organisations decide to collect plastic bottles through bring sites, which are relatively cheap to maintain, but recover only a small amount of bottles: in 2006, 80 per cent of bring sites in the UK recovered less than 2 kilograms of plastic per household per annum. Kerbside collection schemes are more convenient for the public and, consequently, more popular. They tend to recover at least 5 kilograms of plastic per household per annum. However, kerbside collections can be less popular with local authorities, because they tend to incur more costs.

Organisations that operate kerbside schemes are faced with the additional task of deciding how to transport plastic along with other materials. They must determine whether to sort at the kerbside, which effectively reduces contamination but is labour intensive, or at a Materials Recovery Facility (MRF), which is expensive to set up, but can result in much faster sorting, especially when automated sorting equipment is used.

Bring sites and kerbside schemes alike must deal with the issue of contamination. According to Recoup, the UK's leading authority on plastics waste management, there are two main types of contamination when recycling plastic bottles: 'general', including other container types, cardboard end pieces and foreign objects, such as cans, paper or textiles; and 'critical', including hazardous items such as sharps or special waste. Jessica Baker, of Chase Plastics, a polythene recycler, comments about 'general' contamination: " If there is considerable cross contamination of other plastics, i.e. food trays and film et cetera, or other recycables, i.e. paper, tin, aluminium or glass, then the cost of recycling goes up a lot, and at worst renders the material only suitable for export."  The presence of 'critical' contamination, on the other hand, often results in the rejection of an entire load.

Eden Community Recycling (ECR) is a not-for-profit company that has, since 2003, been operating plastic bring sites throughout Eden, the most sparsely-populated district in Cumbria. To date, the organisation has collected and recycled more than 350 tonnes of plastics, including 10 million one-litre plastic bottles, through its 23 bring sites.

Plastic banks are collected using a hooklift unit and transported to ECR's depot in Penrith, where the plastics are baled mixed and sent to reprocessors in the UK. Colin Nineham, ECR's Managing Director, explains: " We consulted the public who use our sites and the demand was for mixed plastic, so the only real challenge was to find a UK market for the material."

According to a WRAP survey, around half of organisations operating bring sites have reported 'always' or 'often' having issues with overflowing or contamination. However, Nineham says: "At ECR, we get very little trouble with contamination; I believe this is down to the simplicity and range of services we offer." The fact that the company collects mixed plastics undoubtedly helps, but it also means that they receive less money for every tonne of recyclate.

ECR plans to adapt to become even more successful in future. Nineham says: "We currently only collect from bring sites, partly because that is how it started and partly because we live in such a sparsely populated area and we are self funding. I would be happy to discuss the possibility of kerbside collections at any time with anyone who was prepared to fund it."

Mid Devon Community Recycling (MDCR) is a not-for-profit community company that has had funding to collect milk bottles from the kerbside since 2005. It works in partnership with Mid Devon District Council and its kerbside scheme services the 32,875 households in the Mid Devon Area. However, funding is still an issue for MDCR. At the moment, the local authority does not have the budget to add drinks bottles to the roster of recyclables MDCR collects. So, for the time being, the company only accepts HDPE milk bottles, of which it collected 20 tonnes in the past three months alone.

The organisation decided to sort recyclables at the kerbside, rather than at an MDF. It's a decision that General Manager, Ken Orchard described as a no-brainer: "It's not capital intensive as an MRF would be, so it suits the community sector; it leads to cleaner material, which gets us more money per load; it's cheaper; it leads to better working conditions for our employees and it encourages homeowners to take responsibility for the recyclables they put out for collection." Orchard says workers at MRFs have to put up with unfavourable conditions, including working in a very noisy environment, standing inside all day and doing monotonous activities that could lead to repetitive strain injuries.

Because the workers sort materials at the kerbside, MDCR does not have any issues with contamination, but, according to Orchard, local authorities around them do encounter problems. Organisations that that use MRFs cannot get the quality of material as high as those that hand sort, he says, and the consequences can be far graver than a mere lowering of price obtained for tonne of recyclate: "Occasionally, things like dirty nappies get through and mills refuse to buy from that authority until they change their sorting system."

Newport Wastesavers is another community not-for-profit recycling group. It provides a kerbside service for 53,500 households. The company accepts all forms of soft plastics for recycling - bottles as well as food containers - and collects 120 tonnes of plastic a month. This works out to an impressive 25 kilograms per household per annum.

Paul Jones, Chief Executive of Wastesavers, indicates that collecting plastics puts an upward pressure on the cost of collecting recyclables, but is a necessary service for the public. Wastesavers has responded to the need to collect plastics by creating a bespoke collection vehicle that allows plastic to be loaded on a low level, but stored above. Jones says the vehicles were designed for "efficient collection, minimum handling, plus good payload to volume ratio." Once the materials arrive back at the depot, the plastics are baled mixed and sent for reprocessing, which Jones finds to be more cost efficient than separating into polymer types.

Like MDCR, Wastesavers sorts recyclables at the kerbside, and Jones says the system minimises contamination: "We can leave any general contaminates behind and crew training and education linked with supervision can eliminate this problem."

Unlike MDCR, however, Wastesavers is in a growing minority of recycling organisations that offer mixed plastics collections. In doing so, Jones has identified another type of contamination: 'contractor specified'. He comments: "They are things that are contaminates in the mix of plastics or, at best, undesirable. However, the scheme specifies that we will collect them." While official Wastesavers literature asks for only plastic bottles, in practice, they accept all forms of soft plastic to comply with public demand.

Jones explains what he terms 'the infinite spiral of public misperception': "Five years ago, ask a member of the public about their recycling scheme and they would say, 'I really do my bit with recycling, but I think it's outrageous that the council doesn't take plastic.' The councils start collecting plastic bottles and the public complains because the council won't take yoghurt pots and margarine tubs. So the councils start collecting a lower grade of plastic to include yoghurt pots and margarine tubs and the public complains that the council doesn't collect toys and hard plastic. Basically, we are getting to a state when councils are having to collect a wide range of plastic, not for environmental benefits but for public benefits. This has hugely detrimental effect on quality."

Jones points out that there still is a good reason to bend to the popular will in this matter, though: "If you keep the public on-side with all this plastic recycling, then they will have greater system acceptance and therefore greater participation and higher diversion rates of other materials. So, overall it is better."