HR: 11:50h
AN: H22C-06 INVITED     [Abstracts]
TI: Effectiveness of Various Source Zone and Dissolved Plume Remediation Measures for Sites with Residual DNAPL and DNAPL Pool Sources
AU: * Christ, J
EM: john.christ@usafa.af.mil
AF: U.S. Air Force Academy, 2354 Fairchild Drive, Suite 6J-159, USAF Academy, CO 80840, United States
AU: Parker, J
EM: parkerjc@ornl.gov
AF: University of Tennessee, Subsurface Science Group Environmental Sciences Division Oak Ridge National Laboratory , Oak Ridge, TN 37831-6036, United States
AB: A model is described for transient field-scale DNAPL dissolution kinetics with (i) source zone biodecay, (ii) dissolved phase transport downgradient of the source, and (iii) dissolved plume mass losses due to biodecay and volatilization. The source model considers effects of DNAPL "architecture" on the functional dependence of dissolution kinetics versus source mass depletion, based on results of a high-resolution numerical simulations and field studies by a number of researchers. A formulation is presented that is convenient for model calibration and for uncertainty analyses on forward predictions. The model is employed to evaluate differences in source depletion and dissolved plume attenuation over time for sources dominated by residual DNAPL ("ganglia") or by DNAPL pools or lenses. In addition to the case of natural attenuation, the effectiveness of various source zone and dissolved plume remediation strategies are investigated, including: partial source zone mass removal, partial source zone flow reduction, enhanced source zone biodecay, enhanced source zone mass transfer kinetics, enhanced dissolved plume biodecay, enhanced volatilization, and various combinations of these. For each source type and remediation scenario, source mass flux and concentrations at downgradient receptor locations are evaluated versus time. Times to achieve remediation criteria are compared for each case. Remediation times are generally greater for pool-dominated sources than for residual DNAPL sources under otherwise comparable conditions; however, successful remediation can be achieved even for more intransigent pool-dominated problems by using more aggressive source strategies and/or by combining multiple strategies, especially if compliance points are further downgradient from the source or risk-based cleanup levels can be employed.
DE: 1831 Groundwater quality
DE: 1847 Modeling
SC: Hydrology [H]
MN: 2007 Joint Assembly