New Delhi: Scientists have developed a low-cost solution to harvest high-quality distilled water from cooling towers of power plants to meet the increasing drinking water demand across regions.

The findings by a team of engineers from the Massachusetts Institute of Technology (MIT), Cambridge, US, were reported in the journal Science Advances. The researchers, who had started improving the efficiency of fog collectors by using electric forces, ended up developing a system which could help recover water that was lost in plumes of cooling towers of power plants.

The new approach involves zapping the air that is rich in fog with a beam of electrically-charged particles, or ions. The water droplets become electrically charged and can be drawn towards a mesh of wires placed on their path. The droplets can then be drained into a container.

Capturing evaporated water is an established distillation process, and the new solution would help capture pure water, even if the cooling water was salty or contaminated. The water could then be piped to a city’s drinking water system, or used in processes that require pure water, such as in a power plant’s boilers.

The findings could solve drinking water problems across regions, given the fact that power plants are the largest industrial user of water, and are exceedingly contributing to water-stress.

In India, almost 90% of thermal power generation depends on freshwater, which is used for cooling of power plants. But, much of that water is lost as clouds of vapour, since the currently used systems to capture droplets are not very efficient.

With more than 1.1 billion people lacking access to potable water worldwide, the technology could potentially be used to develop a significant source of clean, safe drinking water for coastal cities, where seawater is used to cool local power plants, according to the research paper.

Researchers highlight that a typical 600-megawatt power plant, could capture 150 million gallons of water a year. “This represents 20-30% of the water lost from cooling towers," said co-author and associate professor Kripa Varanasi from the MIT. “This can be a great solution to address the global water crisis."

It could also have immense potential for India, where water scarcity is hampering electricity generation. According to a recent report by World Resources Institute (WRI), 40% of the country’s thermal power plants are located in areas facing high water stress and most of the existing plants could see increased level of water competition by 2030.

It also provides an effective way to provide water desalination services to power plants at a cost which would be one-third of building a new desalination plant. “It could offset the need for about 70% of new desalination plant installations in the next decade," said Varanasi.

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