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161: Drinking water from fog

Problem:

Drinking water is becoming a rare commodity. Industrial development is filling our rivers, seas and oceans with toxic pollutants which are a major threat to human health.

In some regions, such as in the Atacama and Namib desert. it almost never rains, leaving a challenge to find drinking water. Lima, Peru, is at high risk for water shortages. With a population of 10 million, the world’s second-largest desert city receives a paltry 0.3 inches of rain each year, and relies on just three rivers to provide drinking water to residents.

Solution:

Fog-catching nets


In 2009, German man-and-wife conservationists Kai Tiedemann and Anne Lummerich helped the residents of Bellavista, Peru, plant 800 new river she-oak trees, such as those seen above, with water collected from fog-catching nets.

During their research they found that trees with vertical, needle-like leaves work as an organic net to which drops of water adhere. As part of their “Green Desert Project”, they later went on to develop artificial nets that could also capture water. With large sheets of mesh strung up on hillsides, it is possible to harvest the thick mists that drift across the arid Peruvian landscape.

Tiny droplets condense on the netting and dribble down into pipes that carry the water into containers where it can be used to irrigate crops or even as drinking water. Each net can capture between 200-400 litres of fresh water every day, providing a new source of water for communities that have had no easy access to regular supplies.

Abel Cruz has founded an organisation to help supply water to desert communities in South America called ‘Peruanos Sin Agua’ (‘Peruvians without Water’). This has helped to install more than 2,000 of these fog catching nets providing fresh water access to 60,000 people in eight rural communities across Peru as well as in Bolivia, Colombia and Mexico.

This has enabled greening drought areas for agriculture: raising chickens, cultivating figs, grapevines and olives. In the provinces of Cusco, Tacna, Arequipa, the water is for human consumption. In areas where there is little air pollution, the water from fog catchers is pure – but in more urban areas the water must be treated before drinking. (lossingua.org)

Elsewhere in Chile, architects Alberto Fernandez and Susana Ortega have designed angular kite-like structures as well as huge, spiral-shaped fog harvesting towers that aim to create a large surface area to collect water from as high as possible in the fog. A another project in Chile, called “Proyecto Niebla”, uses 3D structures to enable the collection of fog regardless of the wind direction.

Can bio mimicry be used to harvest water? Biologist Miguel Galvez of Brighton, Massachusetts was inspired by the body of the Namib Desert darkling beetle (Coleoptera, Tenebrionidae) which hydrates itself by using a patchwork of water-attracting and water-repelling regions on its shell to capture and drink water droplets from the air.

In 2011, Galvez and Deckard Sorensen started up NBD (Namib Beetle Design) Technologies in Boston to make devices that could collect water from humidity in the air, an idea often described as a kind of “self-filling water bottle.”

Realising that there was a much more promising market in the industrial sector, NBD began to work with big companies that might want to use its technology to improve their products—anticorrosive paints, waterproofed electronics, and machines that handle a lot of water.

NBD obtained a federal grant to explore whether its specialized coatings can improve the performance of steam condensers, which are used by electric power plants and desalinization facilities to convert steam into liquid water.

NBD became the global leader in surface modifying coatings and additives for advanced liquid wettability. For large-scale water harvesting NBD obtained a second federal grant to determine whether it can improve the performance of “fog nets,” a water-collecting wire mesh that pulls condensation from the air and collects it as liquid water.

With an increased R&D team, NBD has produced a new kind of nanotechnology polymer, which can be manipulated to make it either hydrophobic or hydrophilic depending on the needs of a potential customer.

In 2017, NBD Nano introduced the first in its line of RepelShell products, an injection-grade additive that makes plastic surfaces highly repellent to water, dirt, mud, and ice. Immediate applications for NBD’s patented RepelShell for plastics include mud- and water-resistant athletic footwear, anti-stain electronics, self-cleaning non-woven fibers, and anti-stain textiles.

Discover Solution 162: BPA-free food cans

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