| Contamination in the vadose zone by light non-aqueous phase liquids (LNAPLs) is a widespread occurrence. Efficient remediation of soil and groundwater contaminated with LNAPL is of paramount concern to the environmental engineers. A numerical modeling study of surfactant enhanced aquifer remediation (SEAR) by promoting mobilization of LNAPL was conducted to simulate recovery of trapped residual LNAPL as free product. UTCHEM, the University of Texas Chemical flooding simulator, was successfully used to model various steps involved in SEAR: initial oil spill, primary pumping, and secondary pumping. Two different methods of surfactant application during secondary pumping to enhance mobilization of were modeled: infiltration from soil surface for vadose zone treatment, and injection at subsurface for capillary fringe treatment. Subsequent evaluation of hydraulic controls to improve oil removal efficiency resulted in 98% free product recovery. The promising result demonstrates the viability of an alternative SEAR approach that promotes mobilization as dominant mechanism. |
