Source: http://www.huffingtonpost.com/2015/05/14/salty-water-india_n_7276912.html?utm_hp_ref=green&ir=Green

A group of engineers from MIT invented a system that relies on solar energy to bring water to rural areas in India. Instead of relying only on electricity, this system uses electrodialysis– employing solar power to charge up lead-acid batteries, which would in turn charge up electroactive membranes that act like magnets for the positive and negative ions of dissolved salt in the water. This system is low-cost, and can desalt 2,100 gallons of water per day.