Enhancement of Remediation of NAPL Contaminated Fractured Permeable Formations-Modeling Study

This study has been originated and motivated by a series of discussions, concerning the containment and use of polluted groundwater of a comparatively wide part of the Coastal Plain Aquifer (CPA) in Israel that has been polluted by kerosene [light nonaqueous phase liquid (LNAPL)]. A variety of types of information have indicated that hydraulic barriers should be employed. However, such an operation should be subject to optimize the aquifer remediation, which is also obtained due to the hydraulic barrier operation. The particular part of the CPA is comprised of "fractured permeable formation" namely sandstone interbedded with sandy clay lenses. Therefore, in this study a simplified conceptual model is applied to represent the formation and implement the pump-and-treat remediation procedure, whose major objective is cost effective containment of the polluted area. Three physical measures, aimed at the remediation process enhancement, have been analyzed: (1) changing the pumping-injection discharge, (2) use of surfactant additives (or other types of solubilizing agents), and (3) use of controlled means to increase the aperture size and density of fracture segments. Possibly, an appropriate combination of such means is most feasible and should be determined. However, the present study evaluates the separate possible effects of each one of such measures on major parameters of the remediation process (time and volume of water that should be treated). It is shown that a particular set of parameters can be applied to evaluate the optimal design and adequate combination of such physical measures aimed at remediation enhancement.