HR: 10:20h
AN: H42C-01    [Abstracts]
TI: A Modified Light Transmission Visualization Method for DNAPL Saturation Measurements in 2-D Models
AU: * Bob, M M
EM: bob.mustafa@epa.gov
AF: US Environmental Protection Agency, Office of Research and Development, Robert S. Kerr Environmental Research Center, Ada, OK 74820, United States
AU: Brooks, M C
EM: brooks.michael@epa.gov
AF: US Environmental Protection Agency, Office of Research and Development, Robert S. Kerr Environmental Research Center, Ada, OK 74820, United States
AU: Mravik, S C
EM: mravik.susan@epa.gov
AF: US Environmental Protection Agency, Office of Research and Development, Robert S. Kerr Environmental Research Center, Ada, OK 74820, United States
AU: Wood, L
EM: wood.lynn@epa.gov
AF: US Environmental Protection Agency, Office of Research and Development, Robert S. Kerr Environmental Research Center, Ada, OK 74820, United States
AB: In this research, a light transmission visualization (LTV) method was used to quantify dense non-aqueous phase liquids (DNAPL) saturation in two-dimensional (2-D), two fluid phase systems. The method is an expansion of earlier LTV methods and takes into account both absorption and refraction light theories. Based on this method, DNAPL and water saturations can rapidly be obtained point wise across sand-packed 2-D flow chambers without the need to develop a calibration curve. The method was applied to measure, for the first time, undyed DNAPL saturation in small 2-D chambers. Known amounts of DNAPL, modeled by tetrachloroethylene (PCE), were added to the chamber and these amounts were compared to results obtained by this LTV method. Strong correlation existed between results obtained based on this method and the known PCE amounts with an R2 value of 0.993. Similar experiments conducted using dyed PCE showed a stronger correlation between results obtained by this LTV method and the known amounts of dyed PCE added to the chamber with an R2 value of 0.999. The method was also used to measure dyed PCE saturation in a large 2-D model following sparging experiments. Results obtained from image analyses following each sparging event were compared to results obtained by two independent techniques, namely gas chromatography-mass spectrometry (GC/MS) analyses and carbon column extraction. There was a good agreement between the results obtained by this LTV method and those obtained by the two independent techniques when experiments were carried out under stable light source conditions, and errors in mass balance were minor. The method presented here can be expanded to measure fluid contents in three fluid phase systems and provide a non-destructive, non-intrusive tool to investigate changes in DNAPL architecture and flow characteristics in laboratory experiments. Disclaimer This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.
DE: 1800 HYDROLOGY
DE: 1828 Groundwater hydraulics
DE: 1829 Groundwater hydrology
DE: 1831 Groundwater quality
DE: 1832 Groundwater transport
SC: Hydrology [H]
MN: 2007 Fall Meeting