By 2025, nearly two billion people will experience absolute water scarcity, and two-thirds of the world will survive in water-stressed conditions. More than 1.4 billion people currently live in river basins where water use is more than the minimum recharge levels, according to the UN Development Programme. In 60 percent of European cities with a population of 100,000 or more, groundwater is being used at a faster rate than it can be replenished.
An engineering team from the Massachusetts Institute of Technology (MIT) is working on an innovative solar-based solution to desalinate water in order to provide clean water to rural communities across the developing world. The team, comprising Amos Winter and Natasha Wright, who work at MIT’s Global Engineering and Research Lab, or GEAR, are developing this solution as a part of a competition sponsored by the US Agency for International Development (USAID) and the Bureau of Reclamation.
The desalination project is being supported by Jain Irrigation Systems Inc. of India and by MIT’s Tata Center for Technology and Design, which researches technologies for developing countries. The center is backed by the Tata Group, one of the largest corporations in India.
India has 16 percent of the world’s population but only four percent of its fresh water. Much of this is groundwater, and about 60 percent of it is too salty to be safely consumed by plants, animals, or humans. However, about 70 percent of Indians must drink groundwater, even when it is too salty.
Water desalination solutions traditionally require large amounts of electric power, which is scarce and expensive in the developing regions of the world. Therefore, the MIT team has designed a solar-based solution, which will help people who live off the grid. Secondly, most large desalination plants use reverse osmosis, which wastes about 40 percent of the water.
The MIT system uses electrodialysis, a method that can separate positively and negatively charged ions in salty water by using electrically charged membranes that attract the salt ions like magnets. With this method, only about five percent of the water is wasted. This system relies on a set of solar panels that make it entirely self-sustaining. The package can produce enough water to irrigate a small farm or to serve the daily clean water needs of up to 5,000 people.
General Electric Co.’s power and business unit in Ontario, Canada provided the electrodialysis technology used by the MIT team. The MIT system was recently tested at the Brackish Groundwater National Desalination Research Facility in Alamogordo, N.M. for two nonstop 24-hour cycles. In each session, the system desalted 2,100 gallons of water, making it fit for use in irrigation. It also ran an additional 66 gallons of water through a UV cleaning system to kill bacteria and make it safe to drink.
Source: Boston Globe
Image Credit: Flickr via Anthony Quintano