The SODIS is a method by which solar energy is utilized to remove bacteria and purify water.
This is done by filling plastic bottles with water and placing them in direct sunlight. But so far, it has not been determined how long the bottles will have to be left out in the sun before the water gets completely purified.
Engineering students at the University of Washington have recently won $40,000 for developing the PotaVid at the recently concluded InnoCentive, international competition. The PotaVida solution utilizes an electronic sensor to determine water purity. The Contest stipulation states that solutions should not cost more than $19, and the PotaVid costs around $3.40 to build. The students will now endeavor to convince potential consumers that the system could save lives in a cost- effective manner.