Two-thirds of the planet is water, but just a portion of it serves any real purpose for life on Earth. Already, one in nine individuals lack access to clean water and the World Health Organization expects half of the planet’s population to live in water-stressed environments by 2025. Desalination–the elimination of salts and other minerals out of water — could be an integral innovation in resolving this forthcoming mess, but only if it’s become a sustainable, affordable technology. A group of scientists believe they’re closer to achieving that goal than anyone before them, and may finally have the ability to turn the planet’s vast salt water bodies to some never-ending quarry for potable water, as a result of the power of sunlight.
Based on Akshay Deshmukh, a researcher at Yale University working on desalination technology, the golden standard desalination technologies is powered by reverse osmosis, where a pressure gradient is induced to move water through a semipermeable membrane that is effective at trapping salts and turning saltwater into freshwater. It is extremely effective, but the pumps used to induce this pressure are extraordinarily costly to build, ship, and function –particularly when it comes to treating water with high levels of salinity.
“Because reverse osmosis uses so much power,” says Deshmukh,”you will need quality infrastructure to maintain these pumps going.” Off-grid and poor communities in the developing world just don’t have access to the sort of power required to conduct reverse-osmosis desalination. For these communities, you need a technology that may run off outside energy. Waste energy may work, but if you are trying to run desalination on a practical level–essentially 24/7–you would like to turn to renewable power to drive the procedure.
So you must break free from reverse osmosis. Deshmukh’s research team at Yale is one of several parties heavily involved with Nanotechnology Enabled Water Therapy (NEWT) Systems: a consortium of industry, academic, and government partners launched by the National Science Foundation to create inexpensive, sustainable water-treatment systems which could be utilized off-grid and possibly give millions of people across the globe access to clean water. The water vapor diffuses through the membrane and condenses on the chilly side, while leaving salts behind on the other, alluring side.
“The substances are broadly similar,” says Deshmukh,”to, for example, breathable waterproof coats, where your perspiration and water vapor can go through the jacket because it is hotter, but rain can not go through because it is colder.” Thus the entire process, known as nanophotonics-enabled solar system distillation (NESMD), is basically driven by solar energy. It may be used anywhere the sun shines, which makes it a potentially breakthrough water treatment system for rural and poor communities around the world. Previous tests suggested that the needle was capable of desalinating about 6 liters of water per square meter of membrane area, every hour, with a simple lens which concentrated sunlight to about 17.5 kilowatts. The upcoming trials must attack for something closer to 10 liters of water each hour. That means a square meter of membrane could provide up to 240 liters of water daily.
Admittedly, that is less than what many people are used to: the average American uses between 300 and 380 liters of water daily. But Deshmukh emphasizes the model is a modular system. It is easy to add more membranes to one another and have stacks of these running in parallel at the exact same time, depending on one’s needs. The new testing is functioning under the notion that a huge capacity desalination plant using NESMD technology could create 10,000 liters of freshwater daily, though a small capacity plant could be directed at generating 2,000 liters per day–more than sufficient for one family (an egregious American one). And needless to say, the idea is to scale this up to larger targets after the testing demonstrates what substances and procedures could be further optimized.
NEWT is already making strides to work out how this technology can be deployed by fabricated and deployed by commercial partners, such as Montrose Environmental Group (whose company vice president, Joon Min, is a co-investigator of this DOE-funded study). If the trial goes well, we might quickly see NESMD structures being unrolled earlier than we think, granting those that are coping with water a reprieve they are waiting a long time for.