LNAPL Site Case Study & EPA Confirmation Drilling Results
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Aestus’ GeoTrax Survey™ was used to assess the performance of remediation efforts at a leaking UST gas station site and located a subsurface zone suspected to contain remnant LNAPL contamination
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A technology comparison test was performed using both standard electrical resistivity imaging (ERI) and specialty GeoTrax Survey™ techniques
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EPA’s Kerr Environmental Research Center in Ada, Oklahoma performed independent confirmation drilling work, which demonstrated that GeoTrax Survey™ detected both hydrocarbon blobs in a semi-quantitative manner relative to the measured TPH concentrations
(Halihan et al., 2005)
Halihan, T., S. Paxton, I. Graham, T. Fenstemaker, and M. Riley, 2005, Post-Remediation Evaluation of a LNAPL Site Using Electrical Resistivity Imaging, Journal of Environmental Monitoring, v 7., p. 283-287.
Locating DNAPLs in Hazardous Waste Pits
Standard ERI and Aestus’ GeoTrax Survey™ were run in tandem to compare their ability to locate DNAPLs in a hazardous waste pit. Both scanning technologies involve electrical resistivity measurements and similar field equipment. The methodologies and results, however, are significantly different.


Technology Comparison Conclusions
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Standard ERI did not have sufficient sensitivity to produce usable interpretation and drillable targets
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Erroneous standard ERI derived drilling target on the left would miss high saturations of DNAPL
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Aestus’ GeoTrax Survey™ produced high sensitivity images with drillable targets
Aestus’ scanning technology was developed and proved out at Oklahoma State University. The effectiveness has
been verified through confirmation drilling at hundreds of sites worldwide by Aestus’ clients, which include federal
and state agencies, municipalities, responsible parties, and environmental consulting firms.