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.