SURFACTANT FLOODING OF DIESEL-FUEL-CONTAMINATED SOIL

The use of surfactants to mobilize oil in water solutions has been developed in the oil industry to enhance oil recovery from reservoirs. In contrast, the use of surfactants as a soil-remediation technique is not as well researched. This study used surfactant solutions to leach undisturbed soil cores taken from a site that had been contaminated with No. 2 diesel fuel after a puncture of a transfer line. Preliminary screening of 22 surfactants was performed prior to this study to choose the surfactants to be used in the flooding of the columns. The chosen surfactants resulted in 87% to 97% removal of the diesel fuel during batch extraction. Prior to flooding the columns with surfactants, the columns were leached with deionized water to compare with leaching by the surfactant. Water flooding resulted in removal of < 1% of the diesel fuel. Surfactant solutions removed generally < 1%. The poor removal efficiencies from the surfactant flooding, especially when compared with results from the surfactant screening extractions, were attributed to channeling of the solutions through the columns. The column floodings, therefore, were essentially nonequilibrium extractions, whereas the batch-screening extractions reached an equilibrium.