Writer: Minal Jain

Contrast the picture-perfect beaches of Asia, their miles and miles of blue pristine water with the hundreds of communities of people all around the world, struggling to get access to fresh drinking water.

Saline water in oceans, seas and saline groundwater make up about 97% of all the water on Earth. Only 2.5–2.75% is fresh water. Since human bodies cannot take the salinity in sea water, only up to 2.75% of water is available for drinking and other needs. How can one then exploit the abundance of saline water, and make it into fresh water, enough for entire communities? Many technological methods are available but they are expensive, energy-intensive, and involve large-scale facilities to serve large populations.

Solar desalination, a technique used to remove salt from water via a specially designed still that uses solar energy to boil seawater and capture the resulting steam, which is in turn cooled and condensed into pristine freshwater. Salt and other impurities are left behind in the still. These are called Solar Stills.

One of the challenges in solar still-based desalination has been low efficiency due to the loss of significant energy in condensation. The scientists, from Massachusetts institute of Technology (MIT), U.S. and Shanghai Jiao Tong University, China have come up with a multi-layer solar still which not only desalinates the water, but also recycles the solar energy, boosting overall efficiency by 385 percent.

Some other Solar Desalination technologies. like concentrated Solar Still, can desalinate a wide range of water sources in addition to seawater. It can even treat irrigation waste which would otherwise make the farmland soil less productive year after year.

The water technology keeps improving, with the aim to produce more fresh water and using renewable or less energy intensive methods. With the threat of climate change looming upon us, these new ideas cannot come any faster.

Sources :
https://www.usgs.gov/special-topic/water-science-school/science/desalination?qt-science_center_objects=0#qt-science_center_objects
https://en.wikipedia.org/wiki/Fresh_water
https://www.ecowatch.com/drinking-water-from-seawater-solar-device-2645107732.html?rebelltitem=3#rebelltitem3
https://en.wikipedia.org/wiki/Desalination
https://www.scientificamerican.com/article/can-solar-desalination-slake-the-world-s-thirst/

Image Source:
ecowatch.com
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