Field Test of Air Sparging Coupled with Soil Vapor Extraction

A controlled field study was designed and conducted to assess the performance of air sparging for remediation of petroleum fuel and solvent contamination in a shallow (3-m deep) groundwater aquifer. Sparging was performed in an isolation test cell (5 m by 3 m by 8-m deep). A soil vapor extraction (SVE) system was installed within the cell perimeter for collecting the sparge vapors. The distribution of twelve target compounds, representing the many volatile and semivolatile chemicals making up the contaminant mixture inside the cell, was obtained from soil and groundwater samples taken before and after sparging treatment. Gas samples were collected during sparging from the SVE offgas and were analyzed for specific target compounds, total hydrocarbons, oxygen, and carbon dioxide. Offgas monitoring and soil sample analyses yielded different, and sometimes contradictory, estimates of sparging performance.