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Title: Geophysical Monitoring of Foam used to Deliver Remediation Treatments within the Vadose Zone

Abstract

Foam is a promising vehicle for delivering amendments into the vadose zone for in situ remediation; it is an approach being considered for in situ treatment and stabilization of metals and radionuclides located within the deep vadose zone of the Department of Energy (DOE) Hanford site, WA. A central aspect of evaluating the effectiveness of this approach is the ability to monitor foam distribution, its transformation, and the reactions that it induces in the subsurface, ideally in a non-invasive manner. In this study, we performed laboratory experiments to evaluate the potential of geophysical methods (complex resistivity and time domain reflectometry, TDR) as tools for monitoring foam assisted amendment delivery in the deep vadose zone. Our results indicated great sensitivity of electrical methods to foam transportation and evolution in unsaturated porous media that were related to foam bubble coalescence and drainage processes. Specifically, we observed (1) a decrease of electrical resistivity (increase of electrical conductivity) by over an order of magnitude in both silica sand and natural sediment matrices during foam transportation; (2) an increase of resistivity (decrease of conductivity) by over two fold during foam coalescence and drainage; (3) a distinct phase and imaginary conductivity signature related to the evolutionmore » of water films on sediment grains during foam injection and evolution processes. To assist with the interpretation of these data, TDR measurements were used to monitor moisture content, which provided complementary information about foam distribution and drainage. Our results clearly demonstrated the sensitivity of electrical and TDR signals to foam transportation and evolution in unsaturated porous media and suggested the potential of these methods for monitoring the response of a system to foam based remediation treatments at field scales.« less

Authors:
; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1060660
Report Number(s):
PNNL-SA-86921
EY4049110
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Vadose Zone Journal, 11(4)
Additional Journal Information:
Journal Name: Vadose Zone Journal, 11(4)
Country of Publication:
United States
Language:
English
Subject:
Vadose Zone; in situ remediation; Hanford; radionuclides

Citation Formats

Wu, Yuxin, Hubbard, Susan, and Wellman, Dawn M. Geophysical Monitoring of Foam used to Deliver Remediation Treatments within the Vadose Zone. United States: N. p., 2012. Web. doi:10.2136/vzj2011.0160.
Wu, Yuxin, Hubbard, Susan, & Wellman, Dawn M. Geophysical Monitoring of Foam used to Deliver Remediation Treatments within the Vadose Zone. United States. doi:10.2136/vzj2011.0160.
Wu, Yuxin, Hubbard, Susan, and Wellman, Dawn M. Thu . "Geophysical Monitoring of Foam used to Deliver Remediation Treatments within the Vadose Zone". United States. doi:10.2136/vzj2011.0160.
@article{osti_1060660,
title = {Geophysical Monitoring of Foam used to Deliver Remediation Treatments within the Vadose Zone},
author = {Wu, Yuxin and Hubbard, Susan and Wellman, Dawn M.},
abstractNote = {Foam is a promising vehicle for delivering amendments into the vadose zone for in situ remediation; it is an approach being considered for in situ treatment and stabilization of metals and radionuclides located within the deep vadose zone of the Department of Energy (DOE) Hanford site, WA. A central aspect of evaluating the effectiveness of this approach is the ability to monitor foam distribution, its transformation, and the reactions that it induces in the subsurface, ideally in a non-invasive manner. In this study, we performed laboratory experiments to evaluate the potential of geophysical methods (complex resistivity and time domain reflectometry, TDR) as tools for monitoring foam assisted amendment delivery in the deep vadose zone. Our results indicated great sensitivity of electrical methods to foam transportation and evolution in unsaturated porous media that were related to foam bubble coalescence and drainage processes. Specifically, we observed (1) a decrease of electrical resistivity (increase of electrical conductivity) by over an order of magnitude in both silica sand and natural sediment matrices during foam transportation; (2) an increase of resistivity (decrease of conductivity) by over two fold during foam coalescence and drainage; (3) a distinct phase and imaginary conductivity signature related to the evolution of water films on sediment grains during foam injection and evolution processes. To assist with the interpretation of these data, TDR measurements were used to monitor moisture content, which provided complementary information about foam distribution and drainage. Our results clearly demonstrated the sensitivity of electrical and TDR signals to foam transportation and evolution in unsaturated porous media and suggested the potential of these methods for monitoring the response of a system to foam based remediation treatments at field scales.},
doi = {10.2136/vzj2011.0160},
journal = {Vadose Zone Journal, 11(4)},
number = ,
volume = ,
place = {United States},
year = {2012},
month = {11}
}