Abstract

An innovative application of surfactant-enhanced air sparging(SEAS) technique was developed in this study. Using a laboratory-scale physical model packed with water-saturated sand, air sparging was implemented to remove water-dissolved toluene that was introduced into a specific depth of the system with finite vertical width prior to sparging. An anionic surfactant(Sodium dodecylbenzene sulfonate) was introduced into the contaminated layer as in dissolved form in the toluene-contaminated solution for SEAS, whereas no surfactant was applied in the control experiment. Due to the suppressed surface tension of water in the surfactant(and toluene)-containing region, the toluene removal rate increased significantly compared to those without surfactant. More than 70% of the dissolved toluene was removed from the contaminated layer for SEAS application while less than 20% of toluene was removed for the experiment without surfactant. Air intrusion into the contaminated layer during sparging was found to be more effective than that without surfactant, enhancing air contact with toluene-contaminated water, which resulted in improved volatilization of contaminant. This new method is expected to open a new option for remediation of VOC(volatile organic compound)-contaminated aquifer.

Keywords aquifer remediation, surfactant, groundwater air sparging, surface tension