Narrator: This is Science Today. Some of the most difficult contaminants underground, such as oils and solvents, are easier to get out if you get it hot...just like with clothing. Roger Aines, program leader of the Carbon Fuel Cycle Program at the Lawrence Livermore National Laboratory, says that's what they figured when working on cleaning up Visalia, one of the Environmental Protection Agency's superfund sites.
Aines: We experimented with several different ways to get the ground hot with direct electrical heating and steam injection. And what we used at the Visalia site was purely steam injection. The site that was contaminated was about six acres and to a depth of about 150 feet, so you have this cube of soil that you want to heat up. So you actually have to drill wells into the ground where you can inject the steam and push the steam back and forth between pairs of wells. So, you'll suck up one well and push on the other and then reverse, back and forth. And it took several years to get the entire site hot by doing that.
Narrator: For Science Today, I'm Larissa Branin.