Driest desert lakes thirsty amid fog in Chile

AFP  | Deccan Chronicle

World, America

South-American countries are trying to use ‘fog-harvesting’ technique to collect mist.

The head of research of the Institute of Geography, Camilo del Rio, walks near a fog collection system at the Atacama desert in Iquique. (Photo: AFP)

Alto Patache, Chile: Every morning at dawn, a thick mist known as “The Darkness” blows in from the Pacific to the edge of the Atacama Desert, the most arid place in the world.

After tantalizing the northern Chilean desert with the promise of moisture, the mist evaporates in the sun, leaving the heat to bake the stark lunar landscape.

But the South American country is researching how to use a technique called “fog harvesting” to collect this mist in large quantities and deliver it to communities that currently depend on water shipped in from the city in tanker trucks.

Chilean researchers have patented a device resembling a large window screen to turn the mist into usable water.

These fog harvesters are set up facing the wind, which blows the mist into myriad tiny black threads that criss-cross them.

Instead of passing through, the mist condenses on the polypropylene threads, slowly gathering into drops that eventually seep down into an awaiting container.

The technique is basic but efficient: each window-sized device can collect 14 litres of water a day, said Camilo Del Rio, a researcher at the geography institute of Catholic University in Santiago.The university runs a research center on fog harvesting in the northern city of Alto Patache.

The technology has been exported to Spain, Nepal, Namibia and several other Latin American nations. Other countries collect water with the same principle, but using trees to gather the condensed moisture.

The water tastes like rain, but must be treated for drinking because it contains minerals from the ocean and can harbor bacteria.“Transforming it into potable water isn’t complicated or expensive,” and it can be used as is for bathing or irrigation, said Del Rio.

The research center in Alto Patache comprises six white domes with a weather station, a kitchen, bedrooms and bathrooms — all of which run completely on harvested fog, which provides the facility with more than 200 liters of water a day on average.     

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