A process currently used to decaffeinate coffee may also be useful in removing organic waste from soil, according to researchers at Ohio State University.
Manufacturers now use a supercritical fluid to remove caffeine from coffee beans.
Using a similar technique, scientists have been able to remove contaminants such as DDT from soil, said David Tomasko, an assistant professor of chemical engineering. A supercritical fluid is created when the pressure and temperature of a compound are increased beyond the critical point where the gas and liquid physical states can no longer co-exist. At that point, the compound is in a single state and will not boil or condense. At these conditions, water changes from a liquid to a gas. But the critical point of water is 374 degrees Celsius and 3209 psi.