Playing catch-up with plastics recycling?

Materials World magazine
,
1 Apr 2009
plastic bottles

In the UK, the business of collecting and recycling waste plastics
is continuing to grow, despite the current volatility of the market for
recovered materials. As work begins on Closed Loop Recycling's second
facility in Deeside, Gary Price explores the state of plastics
reprocessing.

Chris Dow stands in the pouring rain surrounded by thousands of used plastic bottles. The stench is overpowering, but the Managing Director of Closed Loop Recycling is oblivious to this as I visit him at the company’s plant in Dagenham, UK. He views these multi-coloured rubbish mountains as a vital resource and a sign that UK households are doing the right thing – environmentally and economically.

‘UK consumers want to take responsibility for the waste they create and not ship it offshore or send it to landfill,’ says Dow. ‘Plastic waste is a valuable commodity and our recycling facility allows us to recapture the resource.’

The company’s facility in Dagenham opened in June 2008 and will convert 35,000t of PET and HDPE bottles back into food-grade packaging every year. Work has now begun on a 50,000t capacity plant in Deeside, North Wales, with financial backing from the Welsh Assembly Government. ‘This is part of an urgently needed infrastructure in the UK,’ Dow explains. ‘The days of sending our waste overseas for someone else to deal with are coming to an end.’

On the surface the recycling sector looks to be in great shape, yet we still dump more waste into landfill than any other European country – about 27Mt a year, according to UK Government figures. Germany, with a population 25% larger than the UK’s, sends just 10Mt of waste to landfill. However, driven by stringent EU legislation, as well as financial incentives, making recovery and processing of recyclables commercially viable, the UK is beginning to catch up.

‘Recycling in the UK is only going to get better thanks to investments from organisations such as the Environmental Services Associations (ESA),’ says Dow. ‘Five materials recovery facilities (MRFs) have been opened by the ESA in the last four months to improve the quality of post-consumer domestic waste. Recovery rates for waste materials are growing by tens of thousands of tonnes every year.’

According to Recoup, the association for plastics recyclers, 4.5bln plastic bottles weighing 182,000t were collected in 2008, an increase of 68% on the previous year. ‘One of the most critical things to plants like ours is having a constant supply of recyclable materials,’ explains Dow. ‘There is £17m worth of equipment at this facility, so we have to make sure we are recycling enough volume to make the process economically practical.’

More to life than money

While Dow is quick to acknowledge that the recycling business needs to pay its own way, he stresses that recyclers should not be pre-occupied with making vast sums of money.

Volatile oil prices have seen the cost of virgin plastic resin plummet in recent months, leading to the collapse of China’s recycling market. Across the industry, prices for some recyclables have halved. ‘People say to me, “you must be rubbing your hands together being able to name your price when buying bottles [from local authorities]”,’ Dow says. ‘The truth is that I don’t want to see borough councils, which have been excellent at collecting plastic waste, punished for doing a good job. I have offered to underpin their price throughout the global economic slowdown because I want councils to stand their corner, continue to work hard and encourage recycling. The environmental benefits are the same whether the bottles cost £50t or £200t’.

Nevertheless the financial incentive for recycling is rewarding, and prices for producing food-grade plastics can triple the value of the material due to demand from retailers such as Marks & Spencer and Coca-Cola. But decontaminating plastic to meet strict EU and US Food and Drug Administration standards is a complex process.

Sorting solutions

‘The decontamination method is different for PET and HDPE streams, and Closed Loop Recycling is particularly proud of this area of the business,’ says Dow.

Once the intricate procedure of sorting and cleaning the bottles is done, the material is flaked and fed into a water tank, exploiting the fact that PET sinks while HDPE floats.

To decontaminate PET, the company uses a process devised by the United Resources Recovery Corporation, based in Spartanburg, USA. The PET flakes are sprayed with caustic soda and passed through a rotating kiln at 200˚C for five hours. The plastic and caustic soda react, dissolving the material’s surface. The flakes are then cooled, dried and passed through a laser Raman spectroscopy sorter. This detects and removes any contaminated items and residue.

The HDPE goes through a Vacurema, a machine that melts the plastic and pushes it through filters. This eliminates food contamination. The material is then extruded, cut into small pellets, cooled and bagged before being sold on to packaging manufacturers.

In the mix

The next goal for recyclers after producing food-grade plastics is commercial scale mixed plastics recycling. ‘The main reason to concentrate on plastic bottles first is because they are nearly always either PET or HDPE, which simplifies the processing,’ says Dow. ‘Mixed plastics bring in other products, such as PVC, polypropylene and polystyrene.’

The UK’s Waste & Resources Action Programme (WRAP) is currently running trials into mixed plastics recycling.

Dow is in favour of co-mingled mixed plastics recycling, as long as the MRF infrastructure is in place to deal with it, but says that, unless a sensible and efficient end-use strategy for the material is established, collection is pointless.

‘I would like to see a consolidation of polymers used in packaging, such as PET and HDPE, which can be taken back up the chain all the way to food-contact packs’, he explains. ‘The problem is that the people responsible do not think about an end-of-life strategy.’

Eco-nightmare?

The introduction of bio-based plastics, such as polylactic acid (PLA), adds another material to the waste stream.

‘At present, bio-based plastics are counter-productive and an ecological nightmare,’ says Dow. ‘They impinge powerfully on plastics recyclers, costing tens of thousands of pounds in new equipment to identify and differentiate them from materials such as PET.’

However, following an analysis of sorting technologies used in the recycling industry, NatureWorks LLC, a biopolymer producer headquartered in Minnetonka, USA, claims that plastic bottles made from the material can be brought into the recycling stream without additional investment.

Colin Williamson, technical expert at recycling firm, Smile Plastics, based in Shrewsbury, UK, argues that sorting the material is only part of the issue. ‘The problem with bioplastics is that they are all biodegradable, so even if recyclers can differentiate them from other plastics on the recycling line, they simply get thrown into landfill,’ he explains. ‘It is here that they degrade and give out methane, which is 24 times more damaging in global warming than CO2.’

Williamson labels PLA as ‘a brilliant marketing concept that is a major hindrance to the recycling schemes that the UK has battled so hard to encourage’.

Closing the loop

Of course, plastics recycling is not simply confined to the bottles market. There is also plenty of work being done to recover polymer waste from automobile components, consumer electronic devices, appliances and other durable sources. But the key issues are the same across the industry – separating the materials and devising an effective end-of-life strategy to reintroduce them to the marketplace.

Axion Polymers’ plastics recycling facility in Manchester, UK, was set up in 2007 to deal with the waste stream generated from products covered by the Waste Electrical and Electronic Equipment directive. These regulations aim to improve the environmental performance of businesses that manufacture, supply and use these appliances. The Axion facility is able to turn mixed and contaminated thick-walled plastics from all polymer types into recyclate suitable for reuse in injection moulding and extrusion processes.

‘There are increasing numbers of manufacturers in the electrical waste sector that want to make a virtue of their recycled content,’ says Roger Morton, Axion’s Commercial Director. ‘But the plastics-rich mixture of materials that is available after the recycling of metals is often considered too complicated to recover and “separate”.’

Axion Recycling’s processing equipment includes magnets for pulling out ferrous metals and optical sensors for sifting out non-white plastics. The company also has techniques for measuring the density of plastic so it is possible to separate polypropylene, high-impact polystyrene and acrylonitrile butadiene styrene.

The business remains tight-lipped about how the separation technology works, but Morton says the process of extracting polymers for high-grade components is much more intricate for electrical goods than it is for packaging.

‘A milk bottle, which is generally made from one material, might be in the distribution channel, to the user and back to the recycling plant within two weeks,’ he explains. ‘A television or a washing machine, containing highly engineered plastics with a range of additives, can be in people’s homes for over 10 years. Some of the additives used to make that product a decade ago may not be used in new equipment, such as certain brominated flame retardants (BFR), which must be disposed of responsibly.’

Axion previously worked with WRAP to extract BFR using methods devised by researchers at Fraunhofer IVV, in Freising, Germany.

Pushing forward

With 20 times more plastic being produced today than 50 years ago, according to UK environmental charity Waste Watch, it is crucial that recycling rates keep improving with continued investment in its infrastructure.

‘Recycling in the UK is still relatively young,’ says Dow. ‘But it is maturing and it won’t be long before we are standing tall with the rest of Europe.’

Further information: Closed Loop Recycling, Smile Plastics and Axion Recycling