Unrecyclability myth is exploded

Before work on the Closed Loop Recycling (CLR) plant in East London's Dagenham Dock could start, the brownfield site had to be minutely examined for unexploded munitions. The whole area had been heavily bombed in World War Two.

And long before the construction phase, supply and demand for post-consumer plastics, specifically from polyethylene terephthalate (PET) and high density polyethylene (HDPE) bottles, was analysed in equal detail. Md Chris Dow is expecting no unpleasant surprises from either rusty bombs or grimy bottles.

Dow specialises in closed-loop environmental optimism, as well as closed-loop plastics. Of changing public attitudes in the UK, he says: "Consumers are responding to the facts of life. The UK is running out of landfill space, and consumers have reacted as they should." Local authorities have taken up that challenge. According to figures from the Waste & Resources Action Programme (WRAP), plastic bottles collected in the UK grew from 108,453t in 2006 to 181,887t in 2007 - an increase of some 68%.

Retailers from Marks & Spencer to Boots have publicly backed bottle recycling and been involved with trials. Brands, like retailers, are increasingly using recycled content as a positive marketing message. And rising virgin polymer prices have done nothing to dampen industry enthusiasm for post-consumer recycled (PCR) plastics. Insiders such as Dow confidently predict long-term price parity between PCR and virgin polymers.

CLR is one of several recyclers now accepting mixed plastic bottles from around the UK, and producing either 'premium' or food-grade PET flake for reprocessing into new packaging. Simply washing the flake is not sufficient to achieve 'food-grade' status, and CLR has added the high-temperature, aggressive United Resource Recovery Corporation (URRC) system to its line (see panel). International users, including Coca-Cola, are known to favour this process. Critically, the Dagenham site is currently waiting to hear whether it will be supplying Coca-Cola Enterprises in the UK, and if so, in what volumes.

The plant will process 35,000t of input material a year, of which around 40% will be PET and some 35% HDPE. As Dow explains, large amounts of material will come from local authorities sorting fully commingled waste. "We have to assume that levels of contamination will be higher, but collection rates will also be higher," he says.

Supply will be managed by waste operator Veolia, which will deliver bottle waste from its own materials recovery facilities (MRFs) and act as a buying agent from other sources.

There is currently much criticism of output quality from MRF's sorting commingled household waste. And although reprocessors such as CLR are equipping themselves to screen out contamination, higher yields will always mean reduced costs. Marketing manager Nick Cliffe says: "MRF output quality will improve. There are so many new facilities being built with the latest sorting technology, and consumers are also getting smarter."

CLR forecasts annual output from its own plant of 11,000t of food-grade PET, which is likely to be split equally between thermoforming and bottle end-markets, says Dow. The plant was producing washed flake for the official opening in late June, and he is promising food-grade output from the URRC kiln by the end of July.

Volumes of food-grade HDPE will be some 6,000t. A contract has already been signed to supply Nampak, which will in turn supply Dairy Crest with recycled polybottles for its milk. The plant should be supplying Nampak by October this year.

To date, investment in the plant has been some £13M, says CLR. Over a year ago, venture capital company Foresight Group invested over £4.5M in the business, and support has also come from WRAP. Earlier this year, Dow said CLR planned to build five new recycling plants around the UK, one a year, depending on supply.

Estimates for the size of the UK market for food-grade recycled PET (rPET) vary, but Dow reckons it could be as high as 100,000t. This figure could grow as converters and packagers seek higher recycled percentages.

Wider markets for plastics

Meanwhile, in June, WRAP presented the results of six months' research into recovery options for mixed plastics. This typically accounts for the bulk (by volume, not weight) of waste left in household bins once plastic bottles, glass, metal, paper/board and (increasingly) food waste have been separated out. But it comprises numerous different polymers and colours, and is often contaminated with residual food.

Nonetheless, Dow is among those saying that future plants could well include capacity for mixed plastics sorting and processing. "Our goal is to establish a plant that can accept similar volumes of HDPE and PET bottles but, if possible, mixed plastics as well," he says.

Working with plastic bottle collection and recycling specialist Recoup, WRAP trialled different combinations of sorting technology, as well as looking at other options from energy-from-waste (EfW) incineration to refuse-derived fuels (RDF).

Plastics technology manager Paul Davidson said at the launch of WRAP's report: "Reprocessing is technically feasible, and can yield high-quality, high-value outputs from the major polymer streams." He added: "We have no business incinerating mixed plastics. Apart from anything else, English incinerators are not very good at converting mixed plastics into electricity."

Others believe that recycling and EfW incineration can both expand in the UK. The WRAP event was chaired by Jan-Erik Johansson, regional director for sector organisation PlasticsEurope. He underlines the fact that in Europe as a whole around a half of all plastics waste is still landfilled. "Recycling and EfW are complementary," he contends. "It will take decades before they start to compete for volumes. In the meantime, we need all the options available for diverting waste from landfill."

Johansson believes that the WRAP implementation project puts the UK at the forefront of full mixed plastics recycling in Europe. But he cautions: "It is vital to secure consistent input streams. Converters need reliable raw material quality so they're not having to adjust their equipment every hour."

Different permutations of line layout, equipment and the number of polymers separated led to two scenarios favoured by the report, one of which would have a capital cost of £15.4M, the other £2.6M. But Dow at CLR points out that lower capital costs can go hand-in-hand with higher operational costs (principally manual sorting), and this can be the critical factor in the longer term.

WRAP plans to help finance the construction of a 40,000t/year mixed plastics plant by 2011, and envisages a UK capacity of 500,000t/year by 2018, including food-grade recycled polypropylene (rPP). Output is also likely to include RDF for use in industry.

Brands and retailers are eager to keep their options on packaging polymers as open as possible, while demonstrating environmental responsibility. The availability of UK-produced rPET and rHDPE is already helping to achieve that objective. The prospect of food-grade rPP and potentially other polymers will make an even bigger difference. FM

The daily grind

Bales of mixed plastics bottles are fed into the Dagenham line at up to 5t an hour.

Once the contents have been broken up, the first separation stage sees waste enter a trommel. This is a revolving drum which filters out small items, such as bottle caps. A second stage pulls out metals. Then a tornado-like air classifier helps to separate and draw out lighter films and labels.

The first of several Pellenc near-infrared optical sorting units separates out PET, HDPE and other polymers. The PET is then sent through a second unit which separates clear, light blue and other coloured grades. The light blue fraction will be used to correct the appearance of clear PCR packaging.

PET waste is channelled through a pre-grinder, which takes flake down to 10mm, and a non-chemical washing unit from German supplier B&B. It is conveyed to the top of a sink/float tank, where further separation takes place of polyolefins (which float) and PET (which sinks).

The 'deep clean' process for PET takes place on a line which combines a caustic wash, pre-drying and up to two hours inside a rotating kiln heated to 200°C. This unit from United Resource Recovery Corporation (URRC) removes a fine layer from each flake. This is followed by rinsing and a Unisensor laser sorting unit - "only the third in the world", according to Closed Loop Recycling.

From the first Pellenc unit, HDPE is processed separately and very differently. For a start, manual sorting will always play a role here, given the risk of pervasive fragrance from detergent bottles. After grinding into flake, this material is sent to a VacuRema melt filtration unit, finally emerging as a food-grade pellet.