Can Harvesting Fog Bring Water To The Thirsty?

Almost 900 million people in the world live without access to safe drinking water—the kind of water that is safe enough to flow straight from the tap into your mouth (with maybe a Brita filter in between). For these people, walking hours each day to faraway and potentially contaminated streams and wells is a way of life, and not one that is particularly conducive to getting much done. That's the developing world water story you've heard 1,000 times before. But now we may not need wells to solve that problem. Because there is, in fact, clean water in the air all around you—if you know how to catch it.

Researchers at MIT are working on a fog-harvesting device (pictured below) inspired by the Namib Beetle, an African species that gathers water droplets from the morning fog on its back and lets the moisture roll into its mouth. The geeks at MIT (sadly) aren't proposing that humans run around wearing beetle-like shells on their backs. Instead, a human-scale fog-harvesting device is made up of a mesh panel that collects water particles into a receptacle.

The researchers are shunning the beetle's hard shell for mesh panels because impermeable objects (like a shell) have to deal with wind currents that drag away water droplets. That's not a problem for a tiny beetle, but humans need to drink more than a few micro-liters of water each day.

The technology still has a long way to go; so far, fog harvesters can capture just one liter of water per square meter of mesh each day. A rural village needs a lot more water than that, and the mesh costs money that these communities don't have.

Still, this is a project we can get behind, and not just because we feel for the people who have to hike everyday for water. As the number of people on the planet increases and the average amount of rainfall stays roughly the same, everyone will need to start thinking of more creative ways to harvest the water around them—including you. Fog catchers aren't a bad place to start. And maybe we'll all look good in giant beetle shells.

[Fog Catcher image credit: Patrick Gillooly. Top fog image from Flickr user j.o.h.n. walker]

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  • ddrake

    Thats great, but at that cost you are better of desalinizing the ocean water, since most fogged up cities are near a body of water anyway. Places that need water like the desert cities don't get fog, avg. humidity in Vegas is less than 8%, I know because I use a bucket of lotion every day.

  • james jones md, phd

    might be just as easy to use a desiccant, capture the water when it's cool and use a batch solar collector to drive it off. The desiccant would be recycled indefinitely. Engineering for the "third world" posing some interesting challenges.

  • Paul Burnett

    Cactus plants in the Atacama desert on the Pacific coast of South America also catch fog. Humans there have learned to use nets to harvest water from fog.

    One of Larry Nivens' "Ringworld" stories involved harvesting atmospheric moisture with chilled surface water catchers.

  • james jones md, phd

    Luke Skywalker's uncle was a moisture farmer. Same idea, just alot more technology. Cooling that mesh, perhaps by heat sinking it to earth a few feet below ground, might significantly increase output.