Remediation Status: Site closed

Why the technology was selected:
This response was chosen because in-situ bioremediation is a complimentary response action to the existing natural attenuation of the groundwater plume. Natural attenuation processes have been active within the plume area since the date (circa 1960's) of the historical release.

Date implemented:
August 2011

Final remediation design:
An in-situ bio-augmentation event was conducted at the site consisted of the
injection of 150 gallons of Cl-Out® was injected into the first GWBU through 10 temporary injection points located across the former PCLE zone in order to supplement the ongoing natural attenuative processes and increase the rate of bacterial destruction. A hydraulic push drill rig equipped with a low pressure injection pump was used to probe each location and inject the microbial solution through the temporary injection points. Approximately 15 gallons of the Cl-Out® solution was injected into each point at a depth of approximately 32 feet below grade. Upon completion of the injection event, the injection points were grouted to the surface and the pavement was repaired.

Results to date:
Concentrations of the constituents of concern have decreased to levels below applicable Class 3 PCLs, and natural attenuation processes will continue to further degrade concentrations into the future. TCE has reported decreases between 59 and 81 percent.

PCE was detected in three of the five samples at concentrations between 0.031 J and 0.170 mg/L.
Each of the concentrations are below the Class 3 GW PCL for PCE (0.5 mg/L).

TCE was detected in each of the five samples at concentrations between 0.011 and 0.270 mg/L.

Each of the concentrations are below the Class 3 GW PCL for TCE (0.5 mg/L).

Cis-1,2-DCE was detected in each of the five samples at concentrations between 0.049 and 0.500 mg/L. Each of the concentrations are less than the Class 3 GW PCL for cis-1,2-DCE (7.0 mg/L).

Trans-1,2-DCE was reported in four samples at concentrations between 0.0014 J and 0.180 mg/L. Each of the concentrations are below the Class 3 GW PCL for trans-1,2-DCE (10.0 mg/L).

Vinyl chloride was also reported in four samples at concentrations between 0.0056 and 0.015 mg/L. Each of the concentrations is less than the Class 3 GW PCL for VC (0.2 mg/L).

Cost to Design and Implement:
$39,101.66

Why the technology was selected:
This response was chosen because in-situ bioremediation is a complimentary response action to the existing natural attenuation of the groundwater plume. Natural attenuation processes have been active within the plume area since the date (circa 1960's) of the historical release.

Date implemented:
August 2011

Final remediation design:
An in-situ bio-augmentation event was conducted at the site consisted of the
injection of 150 gallons of Cl-Out® was injected into the first GWBU through 10 temporary injection points located across the former PCLE zone in order to supplement the ongoing natural attenuative processes and increase the rate of bacterial destruction. A hydraulic push drill rig equipped with a low pressure injection pump was used to probe each location and inject the microbial solution through the temporary injection points. Approximately 15 gallons of the Cl-Out® solution was injected into each point at a depth of approximately 32 feet below grade. Upon completion of the injection event, the injection points were grouted to the surface and the pavement was repaired.

Results to date:
Concentrations of the constituents of concern have decreased to levels below applicable Class 3 PCLs, and natural attenuation processes will continue to further degrade concentrations into the future. TCE has reported decreases between 59 and 81 percent.

PCE was detected in three of the five samples at concentrations between 0.031 J and 0.170 mg/L.
Each of the concentrations are below the Class 3 GW PCL for PCE (0.5 mg/L).

TCE was detected in each of the five samples at concentrations between 0.011 and 0.270 mg/L.

Each of the concentrations are below the Class 3 GW PCL for TCE (0.5 mg/L).

Cis-1,2-DCE was detected in each of the five samples at concentrations between 0.049 and 0.500 mg/L. Each of the concentrations are less than the Class 3 GW PCL for cis-1,2-DCE (7.0 mg/L).

Trans-1,2-DCE was reported in four samples at concentrations between 0.0014 J and 0.180 mg/L. Each of the concentrations are below the Class 3 GW PCL for trans-1,2-DCE (10.0 mg/L).

Vinyl chloride was also reported in four samples at concentrations between 0.0056 and 0.015 mg/L. Each of the concentrations is less than the Class 3 GW PCL for VC (0.2 mg/L).

Cost to Design and Implement:
$39,101.66