Remediation Status: Site closed

Why the technology was selected:
The contaminants are volatile organic compounds in permeable sediments at relatively shallow depths (highest concentrations are at depths ranging from 30-40 ft BLS.

Date implemented:
August 2000

Final remediation design:
The full-scale remediation design is as follows: SVE Wells: 2 Design flow rate: 122 scfm Actual avg. air flow rate: 186 scfm Design vacuum: 123 inches of water column Motor size: 7.5 hp Radius of influence: 50 ft

Next Steps:
The site has met the No Further Action criteria and a Site Rehabilitation Completion Order will be issued.

Cost to Design and Implement:
For all technologies: Design: $36,600 Construction: $204,300

Why the technology was selected:
The contaminants are volatile organic compounds in permeable sediments at relatively shallow depths (highest concentrations are at depths ranging from 30-40 ft BLS.

Date implemented:
August 2000

Final remediation design:
The full-scale remediation design is as follows: Air Sparging Points: 4 Depth: 40 ft bgs Radius of influence: 30 ft Pressure: 26.7 psig Flow rate: 14.4 scfm Motor size: 5 hp

Results to date:
In August of 2002, the AS/SVE system was shut down. An estimated lbs of contaminants had been recovered. Three monitor wells produced groundwater samples with Cis 1,2-DCE concentrations exceeding the MCL (ranging from 76.6 to 516 ug/l). The highest contaminant concentration was detected in a groundwater sample collected from MW002, located directly outside the service door of the facility. The site was placed in monitored natural attenuation. After 3 years of monitoring, the Cis 1,2-DCE concentration in a groundwater sample collected from MW002 (located outside serive door)was 248 ug/l. The decision was made to modify and re-start the AS/SVE system. Two air sparge wells were installed in the area behind the facility. They were constructed of 2-inch diameter Schedule 40 PVC and screened 37.5-39.5 with 40 micron porous HDPE. An additional lateral vapor extraction well was installed in the area behind the facility. It was constructed of 15 feet of 4-inch Schedule 40 PVC with 0.02-inch slot and installed 2 feet below the pavement. The system was re-started on October 18, 2005 using two new air sparge wells, the new vapor extraction well and the existing vapor extraction well beneath the facility floor slab. The system was operated until November of 2006. The site was placed into post-active remedial monitoring. Contaminant concentrations in groundwater declined to below MCLs. Confirmatory soil sampling found no contaminants in soils in concentrations exceeding cleanup target levels.

Next Steps:
The site has met the No Further Action criteria and a Site Rehabilitation Completion Order will be issued.

Cost to Design and Implement:
For all technologies: Design: $36,600 Construction: $204,300

Why the technology was selected:
The contaminants are volatile organic compounds in permeable sediments at relatively shallow depths (highest concentrations are at depths ranging from 30-40 ft BLS.

Date implemented:
August 2000

Final remediation design:
The full-scale remediation design is as follows: SVE Wells: 2 Design flow rate: 122 scfm Actual avg. air flow rate: 186 scfm Design vacuum: 123 inches of water column Motor size: 7.5 hp Radius of influence: 50 ft

Results to date:
In August of 2002, the AS/SVE system was shut down. An estimated lbs of contaminants had been recovered. Three monitor wells produced groundwater samples with Cis 1,2-DCE concentrations exceeding the MCL (ranging from 76.6 to 516 ug/l). The highest contaminant concentration was detected in a groundwater sample collected from MW002, located directly outside the service door of the facility. The site was placed in monitored natural attenuation. After 3 years of monitoring, the Cis 1,2-DCE concentration in a groundwater sample collected from MW002 (located outside serive door)was 248 ug/l. The decision was made to modify and re-start the AS/SVE system. Two air sparge wells were installed in the area behind the facility. They were constructed of 2-inch diameter Schedule 40 PVC and screened 37.5-39.5 with 40 micron porous HDPE. An additional lateral vapor extraction well was installed in the area behind the facility. It was constructed of 15 feet of 4-inch Schedule 40 PVC with 0.02-inch slot and installed 2 feet below the pavement. The system was re-started on October 18, 2005 using two new air sparge wells, the new vapor extraction well and the existing vapor extraction well beneath the facility floor slab. The system was operated until November of 2006. The site was placed into post-active remedial monitoring. Contaminant concentrations in groundwater declined to below MCLs. Confirmatory soil sampling found no contaminants in soils in concentrations exceeding cleanup target levels.

Next Steps:
The site has met the No Further Action criteria and a Site Rehabilitation Completion Order will be issued.

Cost to Design and Implement:
For all technologies: Design: $36,600 Construction: $204,300