Published: June 4, 2015

    Desalinating Ocean Water with Sunlight

    With much of the US Southwest suffering under drought conditions and freshwater supplies increasingly under stress, it’s becoming apparent we need to consider new methods of water reclamation. Bad though the situation is in the Southwest, it’s even worse in drought-stricken developing countries, which lack the USA’s extensive water infrastructure.

    Desalination of ocean or brackish water has been suggested as a way to access currently unusable water, but existing techniques for removing salt from water are expensive and cumbersome. With this in mind, USAID offered the Desal Prize, a competition to develop desalination treatments that were cost-effective, environmentally sustainable, and energy efficient.

    The prize was awarded to a joint effort by MIT and Jain Irrigation Systems for a system powered by solar energy. Solar panels charge batteries, which in turn power the system, removing salt from water using electrodialysis. At the risk of explaining a complicated chemical reaction in overly simple terms, electrodialysis works because dissolved salt has a slight electric charge. By passing an electric charge through water, the system draws salt out of the water. The MIT system includes a UV light, which helps disinfect salt-free water.

    How effective is the MIT desalination system? In tests at the Brackish Groundwater National Desalination Research Facility in New Mexico, the system removed salt from 2,100 gallons of water in twenty-four hours. The next step in development is to run the system under harsh real-world conditions on rural farms. Should it pass this test, the MIT desalinator could provide enough water to supply a small farm.

    The desalinator was designed with developing countries in mind, but if it proves effective, similar technology could be used to relieve droughts in the US. In California alone, many aquifers lie dormant due to their salt content.

    At Pelican, we’re also committed to removing salt from the equation—by eliminating the use of wasteful salt-based water softeners. Our water softener alternative with salt free technology systems remove hard water minerals from your household water without the brackish wastewater of salt-based systems. It’s just one more way we’re committed to providing you cleaner, healthier way while being environmentally responsible.