Surfactant enhanced aquifer remediation has become an acceptable remediation technology to remove groundwater contaminants such as petroleum hydrocarbons and chlorocarbons. There have been several recent field demonstrations of surfactant remediation where surfactants are used to significantly increase the solubility of the nonaqueous phase liquid (NAPLs) in water. The success of these tests was due to a unified approach using site characterization coupled with a laboratory screening followed by 3D modeling of the process for design and optimization purposes.

Here we present 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. UTCHEM is a three-dimensional, multiphase, multicomponent chemical compositional simulator capable of modeling NAPL migration and groundwater flow and transport in aquifers. Simulations are 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 illustrate an approach to design and optimize surfactant-enhanced aquifer remediation processes in a systematic and efficient manner. To make the approach efficient, a framework that can distribute multiple numerical simulations on a cluster of processors has been successfully implemented. This framework integrates a chemical-enhanced numerical model, UTCHEM, an experimental design methodology, and a Monte Carlo algorithm with a robust global optimization search engine to identify the optimal combination under conditions of uncertainty.

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