Learning from Beetle – Pulling Water from Fog .......An Innovation inspired by Nature

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Condensation is a process that involves drawing water from the atmosphere as a result of moist air coming into contact with a cold and dry surface, forming water droplets that flow down the surface once. This is how water collection is done in desert regions where the temperatures drop drastically at night making it easier to collect water via condensation. Water is a scarce commodity in dry regions. An ingenious way of collecting water from fog to provide relief to people in these areas (Reference Science portal article on ‘Water, Water Everywhere.. Pulling Water from Air in Warka Way’).

Scientists draw inspiration from nature to promote and transport condensed water droplets. The idea is borrowed from a beetle (the Namib or Darkling beetle, family Tenebrionidae). It lives in one of the driest habitats in the world  (southwest coast of Africa), and is able to keep itself alive by trapping water on its body from dew and ocean fog.

The beetle is a small bug that lives in harsh and dry conditions, and the nature of its shell makes it a master water collector. Surfaces of wing covers on some darkling beetles gather water using nanoscale bumps and body position. Its hardened shell contains tiny grooves or bumps where water is condensed and channelled to the beetle’s mouth. The beetle is able to trap water or fog by sticking the back part of its body facing the foggy wind. This behaviour is known as fog-basking and this position is important for water collection.

In addition, the shell is made out of a slick wax that resembles Teflon so that water easily flows off its body and into the mouth. A team of researchers from the Harvard and the Wyss Institute have drawn inspiration from this organism to develop a better way to promote and transport condensed water droplets. Researchers were able to make drops grow six times faster than normal by copying the insects' shell geometry.

After spending a considerable amount of time studying the water collecting mechanism of the Namib Beetle, researchers have imitated this astounding method by developing Water Collection Net, Liquid Collecting Permeable Structure and Dew Bank Bottle. This research is an exciting first step towards developing a passive system that can efficiently collect water and guide it to a reservoir.

Water is critical to life. It’s really sad when there are people in the world who are dying due to lack of water. Such ingenious ways of tapping water, if implemented, will give water security to millions all across the globe. Water harvested from fog is quite clean, lacks microorganisms and bacteria. Such a technique of harnessing water would be both environmental-friendly and revolutionary, particularly in the dry areas where it is scarce.

 ‘Biomimicry’  is an approach to innovation that seeks sustainable solutions to human challenges by emulating nature’s time-tested patterns and strategies. Nature has inherited us many things. We have to identify and appropriately use it for our sustainability.

Author: S Sumana, 10th Class, DPS-Nacharam, Hyderabad

(Image source: https://asknature.org/strategy/water-vapor-harvesting/#.WtHLuIiuzIU)

References

1. https://asknature.org/strategy/water-vapor-harvesting/#.WtHLuIiuzIU

2. K.Park, P.Kim, A.Grinthal, N.He, D.Fox, J.C. Weaver, J.Aizenberg. 2016. Condensation on slippery asymmetric bumps. Nature.

3. http://scienceindia.in/home/view_article/288