HR: 08:00h
AN: H11K-01 INVITED    [Abstracts]
TI: Monitoring of Zero-Valent Iron Permeable Reactive Barriers: Electrical Properties and Barrier Aging
AU: * LaBrecque, D J
EM: dlabrec887@yahoo.com
AF: Multi-Phase Technologies, LLC, 420 S. Rock Blvd, Sparks, NV 89431, United States
AU: Adkins, P L
EM: padkins@mpt3d.com
AF: Multi-Phase Technologies, LLC, 420 S. Rock Blvd, Sparks, NV 89431, United States
AU: Slater, L D
EM: lslater@andromeda.rutgers.edu
AF: Rutgers-Newark, Earth & Environmental Sciences 101 Warren St., Newark, NJ 0712, United States
AU: Versteeg, R
EM: roelof.versteeg@inl.gov
AF: Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-2025, United States
AU: Sharpe, R
EM: rsharpe@yaxelyart.com
AF: Formerly Multi-Phase Tech. Present Quantec Geoscience, 8565 White Fir Street # B1, Reno, NV 89523, United States
AB: An innovative method of groundwater remediation invented in the 1990"s, Permeable Reactive Barriers, use sand-sized grains of scrap iron placed in trenches or injected under pressure to remediate a number of organic and inorganic contaminants. Monitoring the aging of these barriers becomes increasingly important as many of these barriers approach their predicted life spans. In-situ resistivity and induced polarization studies have been conducted at six barriers at four different sites: Monticello, Utah; the Denver Federal Center; Kansas City, Missouri; and East Helena, Montana. As some barriers tend to age dramatically faster than others, for this study we consider low permeability barriers as of greater age, as "old" barriers tend to loose permeability rather than exhaust reactive materials. One complicating factor is that two of the barriers studied appear to have issues related to installation. One site, the former Asarco Smelter Site near East Helena, Montana, has been instrumented with an autonomous monitoring system allowing continuous monitoring of the evolution of a relatively new (less than three years old) barrier. The barrier showed surprisingly rapid evolution over the first year of monitoring with changes in both resistivity and chargeability of tens of percent per month. In general, the electrical properties of all of the barriers studied follow a pattern. New barriers are fairly resistive with in-situ conductivity only a few times background (outside the barrier) values. Older barriers get increasingly conductive, with failed barriers showing values of over 100 S/m. The induced polarization response is more complicated. Chargeability values increase over time for young barriers, are largest for healthy barriers in the middle of their lifespan, and decrease as the barrier ages.
DE: 0792 Contaminants (0432)
DE: 1835 Hydrogeophysics
DE: 1895 Instruments and techniques: monitoring
SC: Hydrology [H]
MN: 2007 Fall Meeting