HR: 1340h
AN: H33A-1372 [Abstracts]
TI: Interfacial Area Estimates for a NAPL-Water System and Their Effect on Predicting Groundwater
Remediation Efficiency
AU: * Wildenschild, D
EM: wildend@geo.oregonstate.edu
AF: Dept. of Geosciences, Oregon State University, Corvallis, OR 97330
United States
AU: * Wildenschild, D
EM: wildend@geo.oregonstate.edu
AF: Dept. of Civil, Construction, and Environmental Engineering, Oregon State University, Corvallis, OR
97330
United States
AU: Bradford, S A
EM: sbradford@ussl.ars.usda.gov
AF: George E. Brown, Jr. Salinity Laboratory, USDA, ARS, Riverside, CA 92507
United States
AB:
In mass transfer relationships pertaining to immiscible contaminant clean-up, NAPL-water interfacial area is in many cases
substituted by the total NAPL-blob surface area because the latter is much easier to measure with various imaging techniques.
Apart from results obtained indirectly with interfacial tracer techniques, data on the NAPL-water interfacial area has been
difficult to obtain. We have used high-resolution micro-tomography to image NAPL (Soltrol) and water distribution, and
quantity, in a system of sintered glass beads. The interfacial areas between NAPL and water and for the total NAPL surface
were calculated using various image processing techniques and the results show a significant difference between the
NAPL-water and total NAPL interfacial areas. Using the total NAPL area as a proxy for the NAPL-water interfacial area results
in an order of magnitude overestimation at low saturations and a factor 5 overestimation at high saturations. This has
serious implications for modeled predictions pertaining to clean-up efficiency and resulting concentrations removed during a
pump-and-treat clean-up scenario. We have incorporated the different interfacial area estimates in a numerical model (MISER)
and simulated NAPL dissolution in a realistic porous medium to illustrate the magnitude of the potential error introduced by
using the total NAPL area as a proxy for the NAPL-water interfacial area.
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: Fall Meeting 2005