The American landscape is dotted with over 100,000 deep injection wells..They’re a key part of our energy infrastructure. Without them, you probably wouldn't be able to fill up your tank. Because for every barrel of oil that comes out of the ground, salty and sometimes chemically-laced fluid comes up with it. This so-called produced water has to go somewhere - and much of it injected back into the earth. In the first of a 2 part series, Inside Energy’s Leigh Paterson reports on one company’s bid to get in the game.