Using fracking (hydraulic fracturing) to get oil or gas may fulfill energy needs, but it has a nasty impact on the environment. Among other things, it leaves behind extremely salty water. However, scientists at both MIT and the King Fahd University of Petroleum and Minerals have found technology that could soften the blow. Their approach filters output water through multiple stages of electrodialysis, which uses electrical charges to pull salt through a membrane. This wouldn't make the water drinkable, but it would be reusable -- and that, in turn, would reduce or even eliminate the need for fresh water beyond an initial supply. Oil and gas wells wouldn't deprive local communities of nearly as much drinking or farming water, and they wouldn't have to dispose of quite so many contaminated liquids.
The solution hasn't yet had a real-world test, and there's a concern that the electrodialysis membranes wouldn't hold up if subjected to water with traces of oil and gas. Also, this is just one piece of the puzzle. It doesn't tackle the many other concerns about fracking, such as airborne emissions or the amount of land it consumes. Researchers aren't necessarily using this to justify new fracking projects, though -- theoretically, you could upgrade existing wells and save areas that are already suffering from water shortages, like Texas. While this won't reduce humanity's dependence on oil and help with the transition to clean energy, it could minimize the damage done.
[Image credits: David McNew/Getty Images, Jose-Luis Olivares/MIT]