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Glass for ever

John Stringer finds out what happens to the empties after you've taken them to the bottle-bank. Photography: Lorne CampbellGuzelian

When you take a glass bottle or jar from a supermarket shelf, you may be the first person to touch it - ever. The making and filling of glass containers is completely automated. At Rockware Glass in Knottingley, near Wakefield in Yorkshire, the whole process from molten glass to pallet takes place in 100 yards of huge, hot and noisy machinery.

Outside the factory, above enormous lorries and fork-lift trucks carrying the contents of bottle banks, hangs a sign: "Caution - Children!". Rockware has already welcomed more than 2,000 junior pupils through its gates so they could find out how glass is recycled. Much of the glass used by Rockware is recycled here at Europe's most modern treatment plant. The lorries are weighed and the glass is unloaded, crushed, sorted, cleaned and passed to the furnaces as "cullet" (the name for crushed glass about to be recycled) for heating to a temperature of 1,500oC.

On the whole, however, the UK compares poorly with other European countries when it comes to glass recycling. Rockware can handle far more glass than it gets. That is why the company is keen to "catch 'em young", offering free visits and reasonable coach costs. Close liaison beforehand ensures that the children - and teachers - are well prepared for the experience. In the education room, Joanne Hollins, a qualified primary teacher, introduces the children to a material that lasts for ever. It is a visit that may help to form lifelong habits that could benefit both glass manufacturers and the environment.

Using large illustrations and some memorable comparisons - the average family, for example, uses the weight of four primary-age children in glass every year - Jo explains the importance of recycling to save materials and energy. She tells them how important it is to sort bottles and jars into the right banks, and not to put in window or toughened glass that will cause imperfections in the bottles. Then she wheels out the recycling machine, which replicates on a smaller scale some of the processes that take place in the factory.

While one child loads "cullet" in the form of glass beads, bottle-tops and paper labels at one end of the machine, a team of 10 children sorts the materials as they come down a child-powered conveyor belt, picking out plastic tops, vacuuming up paper and attracting metal caps to magnets. Finally, a torch "laser" picks out the ceramic, which is deflected from the clean cullet. All the stages are identified with icons, and these match posters that the children will later see in the factory itself.

After everyone has had a go at this amazing machine, an interactive video shows the glass-making process from the glowing "gob" of glass to the bottles slowly annealing, or cooling, in huge ovens. The importance of recycling is reinforced before the children make their way past the huge piles of glass to watch the actual process through a window that looks on to the humming factory with its belts and wheels.

Production continues 24 hours a day, every day of the year, stopping just once for maintenance. Rockware has plans to make more of the process visible, so that children can see how the molten glass is turned into bottles.

As the visit ends, teachers are given a CD-Rom with games and activities for infants and juniors that reinforce the lessons of the day. It is a rich experience, covering the science of materials and the responsibilities of citizenship.

Call Rockware's education officer, Joanne Hollins, on 01977 635405 or e-mail The Rockware educational website at offers animated games and activities about recycling BOTTLE FACTFILE

* Far less energy is needed to make bottles and jars from recycled glass than to manufacture them from raw materials. Recycling just one bottle or jar saves enough energy to power a TV set for one-and-a-half hours.

* It takes 3,000 bottles or jars to fill a bottle bank.

* 4,000 bottles and jars weigh about a tonne.

* The amount of iron in the glass helps determine its colour.

* Each family in the UK uses 500 glass bottles or jars in a year.

* Rockware has increased its use of recycled glass by 58 per cent since the recycling plant opened.

* The Rockware Knottingley factory produces 2,000 bottles every minute - the equivalent of the height of Mount Everest in an hour - every day of the year. It takes just five seconds to make one bottle.

* Only 30 per cent of the six billion glass containers used in Britain every year is recycled. Switzerland recycles 93 per cent.

* 28 per cent of people in the UK still do not recycle any household waste.

* Rockware has reduced the weight of a beer bottle from 320g to 200g, using much less glass. The strength of the glass is the same thanks to improved technology.

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