As the world’s population grows an expected 40 to 50 percent in the next fifty years, and our lifestyles become even more resource-intensive, the water-energy nexus has evolved into a serious worldwide crisis. Society will be facing a vital struggle to meet fresh water demand for human consumption, which currently averages 1,000 gallons of water per person, per day, accounting for both direct, and indirect water use.
It is becoming even more critical to develop sustainable, renewable, energy-powered technologies for fresh water supply, especially for arid, developing countries. Current water desalination techniques are very energy-intensive.
One untapped possibility is to use a technology that takes inspiration from an unlikely source—the Namib Desert beetle. Biomimicry offers innovative sustainable solutions for many dire resource-based challenges. At the University of California, Berkeley, Professor Van P. Carey and I were inspired by how the beetle (sp. Stenocara) collects its own drinking water using a unique feature on its back, that aids its survival in a water-scarce desert environment.
The Stenocara’s bumpy back has alternating regions of waxy, water-repellent areas surrounding water-attracting bumps. Moisture in the morning desert fog is captured by the hydrophilic spots, where the drops grow until gravity overcomes the capillary forces attaching them to the surface. The drops then roll down the beetle’s inclined back along the hydrophobic regions that funnel the water to its mouth, quenching its thirst.
In 2001, zoologist Andrew R. Parker, from University of Oxford, first discovered the beetle’s unique feature and tested the effectiveness of such an arrangement for capturing fresh drinking water from fog. He found it to be twice the efficiency of alternative surfaces.
We sought to apply that idea for enhancing condensation in order to collect fresh water more energy-efficiently. We wanted to develop a practical and scalable method of patterning a surface to mimic the beetle’s back. This technology has the potential to save energy compared to existing technologies, while utilizing the waste heat from power plants. In many arid and water-constrained countries in the Middle East or even California, a technology like this can help ensure that people have clean water to drink without using excess energy. Once the proof of concept has been finalized, it will require a year or two to incorporate such surfaces into commercial applications with reasonable production costs.
Illustration by Fatim Hana
