Design of the surfactant flood at Camp Lejeune

A surfactant flood to remove perchloroethylene (PCE) from the groundwater below a dry cleaning facility at Marine Corps Base Camp Lejeune in North Carolina was conducted during the summer of 1999. The design and operation of both the subsurface and surface treatment processes was a large effort involving people from several organizations. Here we present only the design aspects of the subsurface surfactant flood with the emphasis on the flow and transport modeling. The University of Texas numerical model UTCHEM was used for this purpose. The very low hydraulic conductivity in the DNAPL zone at the bottom of this shallow aquifer made this a very challenging project design. Numerous simulations were performed to determine test design variables. These include wellfield configuration and rates, duration of injection and composition of surfactant solution, and hydraulic control achievement using hydraulic control wells. We discuss the simulation results performed prior to the demonstration and emphasize the sensitivity of the model predictions to most important but often uncertain design parameters such as permeability and heterogeneity and initial PCE-DNAPL volume and its distribution.