The PneuLog™ tool has been tested under 21M2 program at Picillo farms site in NH, and also evaluated at the El Toro Marine Corps Air Station in CA.
Innovative Technology Applied at El Toro MCAS
Long, Alexandria (NFESC); Lynn Hornecker (SWDIV); Crispin Wanyoike (Earth Tech).
RPM News, p 10, Spring 2001
A recently implemented innovative technology is capable of continuously measuring air permeability as well as contaminant concentration along a well screen during soil vapor extraction (SVE). The technology was applied at El Toro Marine Corps Air Station (MCAS) by Earth Tech, Inc., using PRAXIS Environmental Technologies patented PneuLog™ system. The technology can be used to assess remediation progress and provide data to help optimize the efficiency of the existing system. The primary contaminant at the cleanup site on El Toro MCAS is trichloroethylene (TCE). An SVE system had been installed late in 1999 and had worked effectively for more than six months. As TCE vapor concentration levels leveled off below the closure thresholds, PneuLog™ was implemented to evaluate the vertical distribution of residual TCE vapors and vapor flow profiles. PneuLog™ was applied to ten representative wells around the site. In general, the PneuLog™ technology combines an airflow probe with a volatile organic compound (VOC) detector to make in situ, real time measurements as a function of depth. The PneuLog™ instrument, which consists of a probe attached to a cable, was lowered into each SVE well. The probe continuously measures contaminant concentration and airflow along the entire well screen length. Soil vapor flow measurements are performed using a downhole flowmeter. VOC measurements are made using a photoionizing detector. The contaminant concentration profiles are calibrated with off-site analyses of vapor samples collected from the well
head. The PneuLog™ results produced useful information. The airflow data showed no areas of restricted airflow, proving that the existing system was operating effectively. The contaminant concentration profiles confirmed that there were no individual pockets of high concentrations of TCE
along the well screen. Additionally, the concentration data demonstrated that the highest concentrations were measured close to ground water and were a result of offgassing from the contaminated ground water. PneuLog™ has been successfully implemented on a variety of DoD and commercial sites across the United States. The data it produces are not only useful for SVE optimization, but can also be used for soil venting design, risk assessments, and accelerated site characterization. Traditional alternatives are available; however, they do not offer the simultaneous
measurement of flow rates and vapor concentrations while they are typically more time consuming and costly than PneuLog™. At El Toro MCAS, it is estimated that utilizing PneuLog™ cost approximately 50% of the amount needed to collect similar data using traditional methods. Contact: Lynn Hornecker, RPM Naval Facilities Engineering Command, Southwest Division, (619) 532-0783, firstname.lastname@example.org.