Remediation Status: Site closed

Why the technology was selected:
The predominant portion of the contaminant mass resided in the unsaturated zone which is composed of relatively permeable soils. Soil vapor extraction is an effective technology for removing VOCs from unsaturated permeable sediments. It was believed that the site could be closed by addressing only contaminated soils.

Date implemented:
May 3, 2004

Final remediation design:
Two 2-inch diameter vapor extraction wells, screened 2-20 ft BLS & one 3-inch diameter vapor extraction well screened 10-25 ft BLS. One of the shallow vapor extraction wells was installed beneath the facility floor slab adjacent to the drycleaning machine. A shallow and the deep vapor extraction well were installed outside the service door of the facility. Five vapor monitoring points were installed, two beneath the facility floor slab and three outside of the facility. The system is powered by a Roots 15 HP blower. Off gas treatment is a 140 lb. G.A.C. unit. Design flow rates: shallow vapor extraction wells - 66 scfm with a design vacuum level of 40 inches-WC. Deep vapor extraction well - 94 scfm with a design vacuum level of 109 inches-WC.

Results to date:
SVE system was run until February 2005 when confirmatory soil samples were collected. Soil sampling resulted in the decision to continue to run the system. In April of 2005, the two interior vapor monitoring points were connected to the SVE system. Confirmatory soil samples were collected again in March of 2006. PCE concentrations in two of the samples exceeded the Soil Cleanup Target Level for leachability for PCE (30 ug/kg) in two samples. However PCE concentration in leachate derived from the Synthetic Precipitation Leaching Procedure run on the two samples was below the Groundwater Cleanup Target Level for PCE (3 ug/L). The SVE system was shut down after operating 21 months and recovering an estimated 17.8 pounds of VOCs. Only one monitor well had ever produced a groundwater sample with a contaminant concentration (PCE) that exceeded a Groundwater Cleanup Target Level. Beginning with the August 2002 monitoring event, no contaminants were detected in groundwater samples collected from monitor wells.

Next Steps:
A Site Rehabilitation Completion Order was issued for the site on July 3, 2006.

Cost to Design and Implement:
$70,400 for all technologies

Date implemented:
May 3, 2004

Final remediation design:
Two 2-inch diameter vapor extraction wells, screened 2-20 ft BLS & one 3-inch diameter vapor extraction well screened 10-25 ft BLS. One of the shallow vapor extraction wells was installed beneath the facility floor slab adjacent to the drycleaning machine. A shallow and the deep vapor extraction well were installed outside the service door of the facility. Five vapor monitoring points were installed, two beneath the facility floor slab and three outside of the facility. The system is powered by a Roots 15 HP blower. Off gas treatment is a 140 lb. G.A.C. unit. Design flow rates: shallow vapor extraction wells - 66 scfm with a design vacuum level of 40 inches-WC. Deep vapor extraction well - 94 scfm with a design vacuum level of 109 inches-WC.

Results to date:
SVE system was run until February 2005 when confirmatory soil samples were collected. Soil sampling resulted in the decision to continue to run the system. In April of 2005, the two interior vapor monitoring points were connected to the SVE system. Confirmatory soil samples were collected again in March of 2006. PCE concentrations in two of the samples exceeded the Soil Cleanup Target Level for leachability for PCE (30 ug/kg) in two samples. However PCE concentration in leachate derived from the Synthetic Precipitation Leaching Procedure run on the two samples was below the Groundwater Cleanup Target Level for PCE (3 ug/L). The SVE system was shut down after operating 21 months and recovering an estimated 17.8 pounds of VOCs. Only one monitor well had ever produced a groundwater sample with a contaminant concentration (PCE) that exceeded a Groundwater Cleanup Target Level. Beginning with the August 2002 monitoring event, no contaminants were detected in groundwater samples collected from monitor wells.

Next Steps:
A Site Rehabilitation Completion Order was issued for the site on July 3, 2006.

Cost to Design and Implement:
$70,400 for all technologies