Environ. Sci. Technol. 1998, 32, 1667-1675
Surfactant Foam/Bioaugmentation Technology for In Situ Treatment of TCE-DNAPLs RANDI K. ROTHMEL,† ROBERT W. PETERS,‡ EDWARD ST. MARTIN,‡ AND M A R Y F . D E F L A U N * ,† Envirogen, Inc., 4100 Quakerbridge Road, Lawrenceville, New Jersey 08648, and Argonne National Laboratory, 9700 Cass Avenue, Argonne, Illinois 60349
Chlorinated solvents such as trichloroethylene (TCE) are prevalent aquifer contaminants. Depending on the degree of contamination, their physical properties may cause them to occur as dense nonaqueous-phase liquids (DNAPLs) making them difficult to remediate by pumpand-treat methods. Successful in situ bioremediation requires mobilization and dispersion of DNAPLs in order to reduce sediment concentrations to levels nontoxic to degradative bacteria. A bench-scale study was conducted to evaluate a novel remediation technology that utilized surfactant foam for mobilizing and dispersing TCE-DNAPLs combined with a bioaugmentation technology to remediate TCE in situ. Results using the anionic surfactant Steol CS-330 showed that foam injected into TCE-DNAPL-contaminated sand columns enhanced mobilization of TCE-DNAPLs. Mobilization was maximized when the foam was injected in a pulsed operation. Injection of foam followed by artificial groundwater (AGW) and then by foam again resulted in flushing 75% of the initial TCE-DNAPL through an 8-in. column (884 cm3 of sand). The residual TCE was dispersed within the column at concentration levels compatible with biodegradation (
