The solution to last month’s challenge – on a cheap supply of pure water – comes from Australia, where lack of water is a problem over much of the country.
The base principle is to condense water out of the air. Even the Sahara Desert manages to have a relative humidity of around 25%. In fact, an old survival trick is to dig a hole, suspend a piece of plastic over it, with a stone to weigh down the centre, and collect the water that condenses on the underside during the night in a cup placed beneath the plastic. Insects and other creatures making use of the same ‘watering hole’ should be removed before drinking.
However, the machines developed by Envirosource in Australia are more sophisticated than that. Hitesh Gohel, the company’s UK sales representative, says the smallest solutions (from around £800) make up to 24 litres per day of what he describes as absolutely pure, distilled water – usually more than enough for a British office, since average use in the UK is only 15 litres per week.
Water is sucked in at the rear of the machine and condenses on a chilled surface. To prevent biological organisms taking up residence, the water is constantly circulated, filtered and sterilised by an ultraviolet lamp. The company also produces industrial-scale units, producing up to 5,000 litres per day. A commercial greenhouse-scale unit in the offing will produce 200,000 litres per day.
More information at www.envirosource.eu
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