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ASSESSING UST CORRECTIVE ACTION TECHNOLOGIES: LESSONS LEARNED ABOUT IN SITU AIR SPARGING AT THE DENISON AVENUE SITE - CLEVELAND, OH
Citation:
Clark*, T. R., R. E. Chaudet, R L. Johnson, AND C Y. Fan*. ASSESSING UST CORRECTIVE ACTION TECHNOLOGIES: LESSONS LEARNED ABOUT IN SITU AIR SPARGING AT THE DENISON AVENUE SITE - CLEVELAND, OH. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-95/040 (NTIS PB95-188082), 1994.
Description:
In situ air sparging (IAS) has been proposed and installed at an increasing number of sites to address contamination in both the saturated and unsaturated zones. Because of the lack of experimental and substantive performance data, however, the actual performance and effectiveness of this system is not known. Therefore, an objective evaluation of performance data is needed to better determine the effectiveness of this technology.
In response to this need, the EPA Office of Research and Development (ORD) Risk Reduction Engineering Laboratory in conjunction with the EPA Region 5 Office of Underground Storage Tanks, the Ohio State Fire Marshal, Bureau of Underground Storage Tank Regulations (BUSTR), and BP are participating in a field evaluation of an IAS system at a petroleum leaking UST site in Cleveland, OH. The purpose of this field evaluation is to provide performance data that will be independently evaluated by EPA so that the effectiveness of the IAS system installed at thi site can be better understood and thereby assist state regulatory agencies in formulating guidance on IAS systems.
This report presents the results of this study based on site and operational monitoring data provided by BP Exploration & Oil, Inc., over a 2-year period. In general, the chemical data collected indicated an overall decrease of concentrations of benzene, toluene, ethylbenzene, and xylenes (BTEX) in groundwateer to nondetectable levels shortly after startup of the IAS system. Some of the historical chemical data were collected before the Quality Assurance Project Plan (QAPP) was developed and therefore did not meet Quality Control (QC) criteria. The low initial contaminant concentration in groundwater and the large variability in both the chemical and process data collected during the study precludes making any definitive link between the decrease in contaminant concentration and the pereformance of the IAS system at this site. Although these data did not allow a definitive evaluation of IAS system performance, they provided valuable information that was used to develop lessons learned that should be considered during the evaluation of different system parameters. The parameters discussed include dissolved oxygen in groundwater, BTEX concentrations in groundwateer, hydrocarbon off-gas concentrations, pressure and flow rates hydrocarbon and oxygen concentrations in soil gas, and monitoring point placement, in addition, an evaluation of these parameters was presented with considerations for sampling methodologies and data interpretation.