title: Field demonstration of surfactant-enhanced solubilization of DNAPL at Dover Air Force Base, Delaware.
abstract: This study reports on a surfactant-based flood for tetrachloroethylene (PCE) removal from a control test cell at the Dover National Test Site. The surfactant formulation (sodium dihexyl sulfosuccinate (Aerosol-MA or AMA), isopropanol and calcium chloride) was able to achieve a high concentration of PCE in swollen micelles (supersolubilization) without vertical PCE migration. The hydraulic system included eight screened wells that were operated in both vertical circulation and line drive configurations. After 10 pore volumes of flushing, the overall PCE removal was 68% (65% of which corresponded to the surfactant flooding alone). In addition, the residual PCE saturation was reduced from 0.7% to 0.2%, and the concentration of PCE in the groundwater was reduced from 37-190 mg/L before the flushing to 7.3 mg/L after flooding. Recycling the surfactant solution reduced the required surfactant mass (and thus cost, and waste) by 90%. Close to 80% of the total PCE removal was obtained during the first five pore volumes which were operated in an upward vertical circulation flow scheme. No free oil phase was observed during the test. Further analysis of multilevel sampler data suggests that most of the trapped oil remaining in the cell was likely localized in secluded regions of the aquifer, which helps explain the lower PCE groundwater concentration after remedial activities. In summary, this field study demonstrated the feasibility of surfactant-enhanced remediation to reduce the mass in the source zone and significantly reduce the PCE aqueous concentration and therefore the risk associated with the contaminant plume.
authors.affiliation: School of Civil Engineering and Environmental Science, University of Oklahoma, 202 West Boyd Street, Room 334, Norman, OK 73019, USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Childs
authors.forename: Edgar
authors.initials: E
authors.lastname: Acosta
authors.forename: Michael D
authors.initials: MD
authors.lastname: Annable
authors.forename: Michael C
authors.initials: MC
authors.lastname: Brooks
authors.forename: Carl G
authors.initials: CG
authors.lastname: Enfield
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Harwell
authors.forename: Mark
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Robert C
authors.initials: RC
authors.lastname: Knox
authors.forename: P Suresh C
authors.initials: PS
authors.lastname: Rao
authors.forename: David A
authors.initials: DA
authors.lastname: Sabatini
authors.forename: Ben
authors.initials: B
authors.lastname: Shiau
authors.forename: Erika
authors.initials: E
authors.lastname: Szekeres
authors.forename: A Lynn
authors.initials: AL
authors.lastname: Wood
mesh_terms: D019840:2-Propanol / Q000737:chemistry; D002122:Calcium Chloride / Q000737:chemistry; D008823:Micelles; D012989:Soil Pollutants / Q000302:isolation & purification*; D012995:Solubility; D013386:Succinates / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry*; D013750:Tetrachloroethylene / Q000302:isolation & purification*; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D008823:Micelles; D012989:Soil Pollutants; D013386:Succinates; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical; D002122:Calcium Chloride; D019840:2-Propanol; D013750:Tetrachloroethylene; C024599:thiosuccinic acid