There are many enormous problems that the human race is facing in the near future.
Despite the seeming impossible nature of some of these challenges, I believe that the power of human intelligence has the potential to solve them. Things that once seemed insurmountable can be made trivial by a leap in understanding & technology.
One of these problems is how to feed and supply fresh water to the exploding population. There is an abundance of salt water on Earth, so if we can find a way to convert it to fresh water efficiently & cheaply, it would go a long way to preventing hardship or violence over water shortages.
This idea for a portable solar desalination unit won the 2015 Desal Prize, a contest run by USAID to figure out ways to deal with the looming water crisis.
This is the explanation of the process by David L. Chandler of MIT News:
"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, Winter says, leaving fresher water at the centre of the flow. A series of membranes separate the freshwater stream from increasingly salty ones."
Here is the link for the webpage associated with the contest: