It has been a long time since my last post, and in the meantime a severe drought is occurring in the Southwest. Solutions such as desalinization plants could provide some help, but these large-scale plants require energy to operate. They also require saltwater, which is available here but is not available in other places. So I looked into devices that can collect water from air. Consumer products exist, but some of them cost $1000 or more and many of them require electricity to operate or expensive filters. But a desert beetle could illustrate another way to harvest water from the atmosphere.
Several types of beetles in the Namib Desert harvest water from fog. The beetles have different ways to do this; some beetles dig holes to collect water, but other beetles harvest water with their own bodies. The latter method got public attention, inspiring inventors to develop products based on the beetles. The theory is that studying the beetles’ bodies will allow scientists to develop new materials that will make atmospheric harvesting devices more effective.
A journal article from 2010 raises some questions about the original theory. The researchers studied several types of beetles and determined how well they collected water from the air. Instead of discovering that one beetle had a body surface that was more effective at collecting water, the researchers found out that beetles that positioned their bodies to bathe themselves in the fog had the most success. But the original reports still inspired inventors, and the concept of surfaces that can harvest water from the air more effectively remains relevant as well.
In Australia, a drought was affecting farmers. Edward Linacre came up with an atmospheric water harvesting system called the Airdrop after hearing about the Namib Desert beetle. The device is installed underground, where the temperature is lower, helping create condensation. It also uses pipes filled with copper wool, increasing the surface area for condensation. The Airdrop won an Edward Dyson award in 2011. The beetle has also inspired another water harvesting project.
NBD (Namib Beetle Design) Nanotechnologies was founded on the concept illustrated by the beetle. The company’s first project was a water bottle that can condense water from the air overnight. This is a great low-cost and low-energy solution to droughts and water shortages. It was based on the surface of the desert beetle, using a combination of materials that attract water and materials that repel water. While original reports on the water bottle came out in 2012. NBD Nanotechnologies is continuing its work in atmospheric water harvesting and materials science with support from the federal government. In 2015 the company announced that it had received a $750,000 SBIR Phase II grant.
So it does look like certain surfaces and materials can make atmospheric water harvesting more effective, and research in this area appears to be ongoing. And solutions that don’t require an external power source appear possible as well.