By Billy Adams
Sydney - Ditch expensive desalination plants and forget about drinking recycled sewage.
The best way to ensure plentiful supplies of our most precious resource, according to an Australian inventor, is a windmill that conjures up water from thin air.
Inspired by a desert beetle and self-sufficient ancient tribes, Max Whisson is adamant he has found a way that will once and for all end humankind's dependence on rain for life's most essential element.
The retired public health official is used to the Don Quixote jibes, but friends say Max is anything but mad.
Working prototypes - built from scrap metal at a shed next to his home in suburban Perth - have already proved the theory.
It revolves around the little appreciated fact that water, billions of gallons of the stuff, is literally floating all around us.
"Not many people know that there is actually a huge mass of water out there before our eyes," says Whisson.
"The concentrations are low so you have to process a very large quantity of air to extract a decent quantity of water."
He says there are about 10 to 15 litres in every 1000 cubic metres of air, or as he adds: "An average-sized window with a gentle breeze flowing through it will produce a million cubic metres of air every hour.
"That's 10 000 litres of water, and more than enough to give the dog a drink."
Whisson's challenge was to cool the air sufficiently to produce water, mimicking a morning dew in a fashion already demonstrated by dripping air conditioners.
His solution is an innovative windmill which, unlike the conventional three blades, has several blades arranged around a vertical column that can take wind from any direction.
The secret lies in a cooling process kicked off by the blades which propel the air into a "chiller" box where water molecules condense on specially designed plates.
Whisson points to ancient tribes in the area that is now Ukraine who used pyramid-shaped rock structures to cool air and produce their water.
The design of his collection plates was also assisted by analysing the body of a beetle that has adapted to its harsh desert environment in Namibia.
The beetle gets drinking water from fog which condenses on its back before trickling down to its mouth.
That provided the inspiration for fog-harvesting nets used in arid mountainous areas of Africa, South America and Asia, but Whisson believes his design has bigger potential.
Wind powers not only the blades, but also the refrigeration process. Although water can be produced in a breeze as gentle as 2km/h, stronger winds generate more power and therefore water. Even better, the hotter the temperature, the more water the air contains.
Whisson believes a windmill 5m tall and 6m across could generate up to 10,000 litres of water every hour; a lifeline in a country grappling with its worst-ever drought and severe water restrictions.
"The systems we use in providing water around the world have caused the destruction of rivers and ecosystems," says Whisson. "This will work whether there is a drought or no drought." - New Zealand Herald