HR: 11:50h
AN: H42A-07    [Abstracts]
TI: Coupling Surfactants/Cosolvents with Oxidants: Effects on Site Characterization and DNAPL Remediation
AU: * Dugan, P J
EM: pdugan@mines.edu
AF: Colorado School of Mines, Environmental Science & Engineering Division 1500 Illinois Street , Golden, CO 80401 United States
AU: Siegrist, R L
EM: siegrist@mines.edu
AF: Colorado School of Mines, Environmental Science & Engineering Division 1500 Illinois Street , Golden, CO 80401 United States
AU: Crimi, M L
EM: mcrimi@mines.edu
AF: Colorado School of Mines, Environmental Science & Engineering Division 1500 Illinois Street , Golden, CO 80401 United States
AB: Within the last decade, surfactant-enhanced aquifer remediation \(SEAR\), and more recently, in-situ chemical oxidation \(ISCO\) show promise for remediation of dense nonaqueous phase liquid \(DNAPL\) contamination in the subsurface. DNAPL removal is typically difficult to achieve with one remedial technique; however, coupling of treatments can be a highly effective method for remediation of DNAPL contamination. Little research has been completed to date to evaluate such coupling and the factors that impact appropriate engineering design and remediation performance assessment. Partitioning tracer tests (PTTs) are a promising method for estimating the volume and distribution of DNAPL. PTTs have several useful purposes: locating subsurface DNAPL zones, estimating NAPL saturation or volume within these contaminated zones, and providing a quantitative and qualitative means of assessing remediation performance. PTT theory permits direct calculation of the NAPL saturation from the chromatographic separation of a tracer pulse consisting of suites of partitioning and non-partitioning tracers that travel with the advecting groundwater. The PTT has been used with limited success after surfactant/cosolvent recovery but has not been assessed as a performance assessment tool after ISCO. There are several factors that could potentially impact the feasibility of the PTT after ISCO. First, previous batch experiments indicate that partitioning tracers degrade in the presence of the oxidant potassium permanganate. Secondly, tracer partitioning could be inhibited by manganese dioxide film formation after chemical oxidation of DNAPL. Both of these factors have potential to influence partitioning tracer transport, which could lead to inaccurate estimates of the post-remediation NAPL saturation, and therefore remediation efficiency. There is a need for researching PTTs after surfactant/cosolvent coupling with ISCO. In general, DNAPL-zone characterization methods have significant uncertainty, and assessing remediation efficiency is difficult. Effluent concentrations can be monitored in the extraction fluid during surfactant/cosolvent flushing, as an independent measure of mass removed. However, a challenge with ISCO in terms of performance assessment is that there is no way to directly measure mass destroyed, except through post-remediation characterization (i.e., PTTs or soil cores). Column and 2-D cell studies were conducted to investigate removal of DNAPL with surfactant/cosolvent flushing coupled with ISCO using the oxidant potassium permanganate. Partitioning and non-partitioning tracers were used in the pre- and post-remediation studies to investigate the effect of these remedial techniques on the viability of PTT.
UR: http://www.mines.edu/students/p/pdugan/
DE: 1829 Groundwater hydrology
DE: 1831 Groundwater quality
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting