Client:
Services: Concerns: | AFLAC, Columbus, Georgia
Soil/Groundwater Investigation for Leaking UST Site Corrective Action Plans–Part A and Part BSoil/Groundwater Remediation for “No Further Action” Letter Georgia USTMP Standards |
Scope of Services:
AEM was contracted to complete a Corrective Action Plan (CAP)–Parts A and B, along with any necessary remediation at a former convenience store site in Talbotton, Georgia, where Phase I and Phase II Environmental Audits had detected releases of gasoline to soil and groundwater.
AEM completely delineated the extent of contamination, completing numerous soil borings, installing more than 20 groundwater monitoring wells, including a deep monitoring well drilled into bedrock more than 135 feet below ground surface, and numerous soil samples were collected by Geoprobe®. The results of the soil and groundwater assessment indicated that large amounts of free-phase gasoline were present in the former tank pit area and that dissolved benzene, toluene, ethylbenzene, and xylenes (BTEX) were present in groundwater both on site and off site in relatively large concentrations. Up to 5 feet of free-phase gasoline product was measured in monitoring wells.
AEM evaluated a number of technologies for the remediation of contaminated soil and groundwater and proposed dual-phase vacuum extraction (DVE) for removal of the free product, remediation of contaminated soil, and remediation of the dissolved BTEX in the down-gradient plume of contaminated groundwater. AEM then conducted a successful three-day pilot study of the DVE technology, defining the design details for the full-scale DVE system.
The results of the pilot study were submitted to the Georgia Environmental Protection Division (EPD) as part of the Corrective Action Plan (CAP)–Part B Report, which included a design for a full-scale system to remediate the site. The CAP-B presented modeling results that demonstrated that dissolved BTEX outside the source area would biodegrade before impacting any down-gradient receptors, which included a municipal well.
After approval of the DVE system by EPD, AEM procured and constructed the full-scale remediation system in early 1999. After three years of operation, free product thicknesses measured in monitoring wells on site had been reduced to non-detectable levels. Concentrations of dissolved BTEX in groundwater in on-site groundwater monitoring wells had been reduced by approximately two orders of magnitude, from as high as 50,000 parts per billion (ppb) to below 1,000 ppb. Because of the effectiveness of the treatment system on the off-site monitoring wells, AEM avoided the construction costs of expanding the system off site.
AEM continued to monitor the DVE system’s operation and monitored the natural attenuation of BTEX compounds in the down-gradient plume of contaminated groundwater. Subsequently, a "No Further Action Required" letter was secured from Georgia EPD-USTMP.
AEM completely delineated the extent of contamination, completing numerous soil borings, installing more than 20 groundwater monitoring wells, including a deep monitoring well drilled into bedrock more than 135 feet below ground surface, and numerous soil samples were collected by Geoprobe®. The results of the soil and groundwater assessment indicated that large amounts of free-phase gasoline were present in the former tank pit area and that dissolved benzene, toluene, ethylbenzene, and xylenes (BTEX) were present in groundwater both on site and off site in relatively large concentrations. Up to 5 feet of free-phase gasoline product was measured in monitoring wells.
AEM evaluated a number of technologies for the remediation of contaminated soil and groundwater and proposed dual-phase vacuum extraction (DVE) for removal of the free product, remediation of contaminated soil, and remediation of the dissolved BTEX in the down-gradient plume of contaminated groundwater. AEM then conducted a successful three-day pilot study of the DVE technology, defining the design details for the full-scale DVE system.
The results of the pilot study were submitted to the Georgia Environmental Protection Division (EPD) as part of the Corrective Action Plan (CAP)–Part B Report, which included a design for a full-scale system to remediate the site. The CAP-B presented modeling results that demonstrated that dissolved BTEX outside the source area would biodegrade before impacting any down-gradient receptors, which included a municipal well.
After approval of the DVE system by EPD, AEM procured and constructed the full-scale remediation system in early 1999. After three years of operation, free product thicknesses measured in monitoring wells on site had been reduced to non-detectable levels. Concentrations of dissolved BTEX in groundwater in on-site groundwater monitoring wells had been reduced by approximately two orders of magnitude, from as high as 50,000 parts per billion (ppb) to below 1,000 ppb. Because of the effectiveness of the treatment system on the off-site monitoring wells, AEM avoided the construction costs of expanding the system off site.
AEM continued to monitor the DVE system’s operation and monitored the natural attenuation of BTEX compounds in the down-gradient plume of contaminated groundwater. Subsequently, a "No Further Action Required" letter was secured from Georgia EPD-USTMP.
