A full-scale cleanup is being performed using air sparging and SVE to treat MTBE and other contaminants at a service station in Hemingway, South Carolina. Soil at the site consists of silty clays with clayey sand lenses. The SVE system consisted of 70 m (230 ft) of horizontal SVE piping installed immediately below the asphalt parking lot surface of the site. Extracted vapors were treated using a thermal oxidizer. The air sparging system, which began operating two weeks after the SVE system was activated, consisted of 10 vertical sparging wells, each installed at a depth of 7.93 m (26 ft) with 1.52 m (5 ft) well screens. The wells were connected to an air sparge compressor operating at 4.78 kg/cm2 (68psi). Site-specific target levels (SSTLs) for this site ranged from 5 to 80^g/L per contaminant. As of June 2003, the maximum concentrations of MTBE and BTEX in the groundwater decreased, with the SSTLs being met for toluene, ethylbenzene, and xylenes. Maximum MTBE concentrations were reduced from >1,000,000 to 568 ^g/L (99.99% reduction), and maximum BTEX concentrations reduced to 9690 ^g/L. The cost for this application was USD195,515.44
Was this article helpful?