Second will be the verified cost and performance data that each agency can use to advance its baseline remediation techniques. And lastly, this effort will result in a willingness to address other common problems in a cooperative and cost-effective manner. SPSH relies on indigenous soil moisture to create an in situ source of steam that strips volatile and semivolatile contaminants from soils. An electrical current passes through soil, which generates heat due to the soil's electrical resistance. The temperature within the remediation area is increased to the boiling point of water.
Soil moisture becomes steam that is captured by vapor recovery wells for removal.
Soil contaminants are also vaporized and are captured for ex situ treatment. SPSH is an enhancement to soil vapor extraction, which is ineffective if contaminants cannot be easily vaporized or if the soil is tightly bound, as in silts and clays. SPSH's electrical soil heating overcomes this obstacle by raising the temperature of the soil and contaminants, increasing the contaminants' vapor pressure and thus their removal rate. In the early 1990s, researchers at Lawrence Livermore National Laboratory in collaboration with the School of Engineering at the University of California at Berkeley developed Dynamic Underground Stripping. DUS was first demonstrated in the cleanup of an underground gasoline spill at the Livermore site in 1993.