Surfactant/foam process for improved efficiency of aquifer remediation

Results of laboratory studies and preliminary results of a field demonstration are presented for a surfactant/foam process for remediation of ground water aquifers contaminated with organic liquid contaminants, especially chlorinated solvents. Injection of air with the surfactant solution generates foam in zones of high permeability or hydraulic conductivity. As the foam has a high resistance to how of liquid, surfactant solution is diverted to zones of low permeability, thereby improving sweep efficiency of the process. This behavior was confirmed by laboratory experiments using a two-dimensional model packed with two layers of sands having different permeabilities. These experiments utilized sodium dihexyl sulfosuccinate as the surfactant at its optimal salinity with trichloroethylene (TCE) as a model contaminant. The same surfactant was used in the field at a site at Hill Air Force Base in Utah which had a TCE-rich contaminant. The surfactant/foam process reduced the amount of this contaminant in a line-drive pattern about 6.1 m long to a very low average saturation of 0.03%.