The availability of fresh water is dwindling in many parts of the world, a problem that is expected to grow with populations. One promising source of potable water is the world’s virtually limitless supply of seawater, but so far desalination technology has been too expensive for widespread use.
Of the total volume of water on earth, 97.5% is salt water and 2.5% being fresh water. Of the freshwater, only 0.3% is available in liquid form on the surface of the earth. If the new solar-powered desalination machine comes into commercial practice, the world would even forget what water scarcity is.
A new solar-powered desalination technology called “photovoltaic-powered electrodialysis reversal system”, which had been developed by the MIT, has won the top $140,000 Desal prize from the U.S. Agency for International Development (USAID). As there are so many causes like irregular monsoons, drought, global warming etc., for the water scarcity, the world is continuously searching for permanent solutions. Christian Holmes, USAID’s Global Water Coordinator, said in a statement “By 2050, global water demand is expected to increase by 55 percent, and 70 percent of global water use occurs in food production.”
A team of researchers from Massachusetts Institute of Technology (MIT), who collaborated with Jain Irrigation, invented a solar-powered machine that can convert brackish waters into potable drinking water, based on the Electro-dialysis-Reversal principle. While solar-powered desalinization plants are not totally new, they were very expensive and only developed areas like Chile and California could try them. But the current technology seems affordable for even the developing countries to adopt. Last year, a team from MIT conducted a field research in the villages of India, after which they pointed at the solar-powered electrodialysis as a solution where problems like freshwater scarcity, low sanitation, lack of sufficient electric power etc., exist as in any other developing country. The research was funded by Jain Irrigation Systems, an Indian company that builds and installs solar power systems, and sponsored by the Tata Center for Technology and Design at MIT.
“Electrodialysis works by passing a stream of water between two electrodes with opposite charges. Because the salt dissolved in water consists of positive and negative ions, the electrodes pull the ions out of the water, leaving fresher water at the center of the flow. A series of membranes separate the freshwater stream from increasingly salty ones.” the MIT News Office explained.
Jain Irrigation says, the system can clean brackish water with up to 5000 ppm and convert into drinking quality water in a single pass using prefiltration, ED-R (Electrodialysis-reversal) followed by UV (Ultraviolet treatment). While 90% of the water could be recovered (wherein reverse osmosis, it is only 40 to 60%), the rest 5-10% reject concentrate would be dried in a solar pond without creating any environmental hazard. It can also remove hardness, chemicals, pesticides, fertilizers and micro-organisms. Along with being powered by solar photovoltaic cells, the ED membrane also has a long life (about 10 years) – all of which make the system more energy and cost efficient when compared to Reverse Osmosis(RO).
The aim of the competition is to ‘Secure water for food’ by recognizing innovators who invent economic, energy and sustainable environment efficient desalination technologies that can produce potable water for drinking and irrigation purposes in developing countries. Christian Holmes said, “The Desal Prize was developed to supply catalytic funding to capture and support the innovative ideas and new technologies that could have a significant impact.” The USAID said that the MIT-Jain system is designed for low-energy consumption and helps reduce costs for underdeveloped areas that do not have easy access to electricity. While the MIT team got the first place, the second place was awarded to the University of Texas at El Paso (UTEP) Centre for Inland Desalination Systems as they designed a Zero Discharge Desalination (ZDD) technology that reduces water waste in the desalination of groundwater by conventional processes.
Recently, a team of researchers from MIT, together with a team from Kuwait University, has been awarded $5.5million grant for a collaborative research project named “Next Generation Brine Desalination and Management for Efficiency, Reliability, and Sustainability”. It is being funded through the Signature Research Program of the Kuwait-MIT Center for Natural Resources and the Environment(CNRE) by the Kuwait Foundation for the Advancement of Sciences(KFAS) with a performance period of three years. (Source: greenoptimistic)
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