Page last updated at 09:01 GMT, Tuesday, 3 July 2007 10:01 UK

Mechanics of e-waste recycling

By Mark Kinver
Science and nature reporter, BBC News

The process of recycling e-waste

The latest addition to the portfolio of laws designed to cut the amount of rubbish we bury in the ground has finally come into force in the UK.

The Waste Electrical and Electronic Equipment (WEEE) Directive requires at least 4kg of e-waste (eg PCs, TVs, washing machines) to be recycled per person.

Good news for the environment, but past experience shows that the transition from policy to practice is not always seamless.

Remember the fridge mountains? The EU directive to cut the emission of ozone-depleting substances was introduced in 2002, when the UK did not have the facilities to safely remove CFCs from fridges.

While the infrastructure was hurriedly put into place, the pile of fridges grew higher and higher.

WEEE is the fastest growing stream of waste in the European Union. The UK is estimated to produce 1.2 million tonnes of e-waste each year, which until now had mostly ended up in landfill sites.

Thinking big

So are we likely to see a new mountain range of PCs and TVs swamp overstretched recycling facilities?

Unlikely, says Myles Pilkington, communications manager for the Sims Group, the world's largest materials recovery firm.

The directive has been up and running in most European nations for almost two years, where specialised e-waste recycling facilities have been developed.

One of Europe's largest plants is located in Eindhoven, the home town of Dutch electronics giant Philips.

WEEE Directive symbol

With a capacity to process 100,000 tons of e-waste a year, the facility is the blueprint of Sims' "super WEEE plant", which it is about to build in Newport, South Wales.

It is an industrial-scale operation that receives WEEE from all over Europe.

Huge tractors shift the materials around hangar-sized sheds, whether it is computer casing, circuit boards, servers or components.

"The advantage of mechanical dismantling over hand dismantling is the classic reason - you are able to handle larger volumes in a safer way," Mr Pilkington explained.

"Arguably, you can get better purity of separated materials by hand sorting, but that is far outweighed by the cost saving you get through mechanical processing.

"We are hoping that technological advances mean that we will be able to get exactly the same results soon."

Plastic puzzle

The firm's history of material recovery stretches back a century, making its name and its money in scrap metal.

But the hard hats and steel toe-capped boots belie the hi-tech processes behind the massive machinery munching its way through thousands of tonnes of waste.

PC cases waiting to be recycled (Image: BBC)
One of the things that really hit us as a result of the WEEE Directive was the need to recover plastics
Myles Pilkington,
Sims Group

The group's Recycling Solutions division, which looks after its e-waste business, also has responsibility for the research and development strategy.

And e-waste has presented a whole new challenge - plastics.

"One of the things that really hit us as a result of the WEEE Directive was the need to recover plastics," recalled Mr Pilkington.

"Plastics recycling is a new and increasingly important part of our operation," he explained.

"We had never had to think about it before, and suddenly it has become the significant volume of the materials we process."

When the company audited the flow of materials through the Eindhoven plant's gates, it found many devices, such as household appliances, were made mainly out of plastic.

If the company was going to make a success out of processing e-waste, he said, it had to develop ways that could identify and separate the various plastics found in devices.

E-waste shed (Image: BBC)
Sims' Eindhoven recycling plant operates on an industrial scale

"The challenge was how we were going to recover these plastics because they were not compatible with each other.

Mr Pilkington was a little coy when asked about the solution Sims had developed, fearing that he would give too much away to competitors.

He revealed: "We are actually going to have two very different technologies working alongside each other to achieve the degree of separation we want."

One of the technologies was "density separation", which involves passing granulated plastic through different liquids, causing some plastics to float and others to sink.

And the other technology? "It uses sensors to understand the material and an air-gun to blast the plastics in different directions."

Making the grade

While processing plastics is important as far as fulfilling the WEEE Directive is concerned, it is classified as "low grade" material. In other words, the resale value of the recovered material is unlikely to cover the processing costs.

"High-grade materials are predominately metal," Mr Pilkington explained. "Whether in the frame or within the electronics, there are potentially a lot of high value precious metals."

Like the plastics, the metal recovery process involves breaking the components down to the size of thumbnails, after any hazardous parts have been removed manually.

Computer, BBC
1: Lead in cathode ray tube and solder
2: Arsenic in older cathode ray tubes
5: Antimony trioxide as flame retardant
4: Polybrominated flame retardants in plastic casings, cables and circuit boards
3: Selenium in circuit boards as power supply rectifier
6: Cadmium in circuit boards and semiconductors
7: Chromium in steel as corrosion protection
8: Cobalt in steel for structure and magnetivity
9: Mercury in switches and housing

"Then there are sorting processes to get the [metals] into their individual constituents," he added.

These include using powerful "true magnets" to extract ferrous metals, and eddy currents (a rapidly alternating electrical current) to attract the remaining non-ferrous metals like copper wiring.

The Eindhoven plant also has facilities to recover printer cartridges and cathode ray tubes (CRTs) from TVs and monitors.

Across Europe, Sims processed 320,000 tonnes of WEEE in 2006. Two-thirds of this, equivalent to 12.7 million PCs, was handled by "dedicated processes" like the ones at its plant in Eindhoven.

But this is only a small fraction of Europe's estimated annual e-waste of 6.4 million tonnes, admits Mr Pilkington.

"The entire electronic recycling sector within Europe is estimated to be eventually worth six billion euros (£4.1bn), so there is still a long way to go."

New e-waste recycling laws begin
01 Jul 07 |  Science & Environment
UN outlines global e-waste goals
06 Mar 07 |  Science & Environment
How to make computers greener
08 Mar 04 |  Technology
Do mobile phones cost the Earth?
01 Dec 06 |  Science & Environment
Q&A: WEEE Directive
01 Jul 07 |  Science & Environment

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