Surfactant Remediation of Soils Contaminated with Chlorinated Solvents

by
Douglas Shotts, MSE

University of Texas at Austin, 1996
Supervisor: Gary A. Pope

This thesis contains the study of two techniques which could be used in the remediation process of dense non-aqueous phase liquids within typical aquifers: (1) the use of partitioning tracers to locate contaminated zones within the aquifer, estimate the volume of contaminant within the tracer swept volume, or assess a remediation process performance, and (2) the use of surfactant enhanced aquifer remediation to remove contaminant from the aquifer.

A partitioning interwell tracer test is where tracers are injected into an aquifer through one well and produced from another. A chromatographic lag of the tracers is observed in the produced fluid depending on the tracer partition coefficient. This chromatographic lag can be used to note the presence of a contaminant and estimate the volume of contaminant between the injection and production wells. Performing this test before and after a remediation process can tell you how much of the contaminant was removed.

Surfactants can be used in a remediation effort to either enhance solubilization of existing contaminant or mobilize the free phase trapped contaminant. Each contaminant encountered requires that phase behavior experiments be performed in order to predict the behavior of the surfactant with the contaminant, the ground water in the aquifer, varying amounts of salts, and any added chemicals to the surfactant solution such as co-solvents or polymer.

The use of xanthan gum in the surfactant solution was initiated in order to control the sweep efficiency of the displacement of the ground water with the surfactant solution. The polymer was used in phase behavior studies, surfactant floods, and tracer tests.

Several batch phase behavior studies were performed. Two different contaminants were examined, (1) trichloroethylene, and (2) a field contaminant obtained from Hill Air Force Base, Utah. Several column experiments were performed to assess the performance of either tracers, surfactants or both. The results of these studies and how they relate to the remediation of dense non-aqueous phase liquid are the main objective of this thesis.

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