Remediation Status: In active remediation

Why the technology was selected:
In-situ chemical oxidation has been documented as an effective remediation technology for the remediation of chlorinated solvents in groundwater. In-situ treatment was conducted to minimize any potential movement of the plume while creating a environment conducive for COC destruction. The response action also compliments the natural attenuation processes to provide long term stability within the contaminant plume. KMnO4 was selected as the oxidizing solution based upon the nature and location of the contamination, the size of the contaminated area, the type of soil present, and the hydrogeology of the area.

Date implemented:
June 2011

Final remediation design:
An in-situ chemical
oxidation event was completed June 2011.
200 gallons of a KMnO4 solution is
injected into the first GWBU
through 16 temporary injection points. A
second in-situ chemical oxidation event
was completed January 2012. 200 gallons
of a KMnO4 solution is injected into the
first
GWBU through 14 temporary injection
points. A third in-situ chemical
oxidation event was completed April
2012. 120 gallons of a KMnO4 solution is
injected into the first GWBU
through 8 temporary injection points.

Results to date:
Sampling data shows site wide decreases in concentrations due to the in-situ chemical oxidation events. Concentrations of PCE have decreased between 50 and 80 percent over the course of the response action period. A similar decrease in the oncentrations of TCE and cis-
1,2-DCE has occurred during this same period. Groundwater monitoring data has indicated that the plume is not laterally mobile. Concentrations in other monitoring wells remain stable or are declining over the past several years.

Approximately 12 to 15 cubic feet of contaminated soil was removed from the site.

Next Steps:
Continuing a regular groundwater monitoring program to establish temporal trends in the groundwater monitoring data
and monitor the effectiveness of the groundwater response action.

Additional rounds of ISCO are also planned.

Cost to Design and Implement:
$78,000

Why the technology was selected:
In-situ chemical oxidation has been documented as an effective remediation technology for the remediation of chlorinated solvents in groundwater. In-situ treatment was conducted to minimize any potential movement of the plume while creating a environment conducive for COC destruction. The response action also compliments the natural attenuation processes to provide long term stability within the contaminant plume. KMnO4 was selected as the oxidizing solution based upon the nature and location of the contamination, the size of the contaminated area, the type of soil present, and the hydrogeology of the area.

Date implemented:
June 2011

Final remediation design:
An in-situ chemical
oxidation event was completed June 2011.
200 gallons of a KMnO4 solution is
injected into the first GWBU
through 16 temporary injection points. A
second in-situ chemical oxidation event
was completed January 2012. 200 gallons
of a KMnO4 solution is injected into the
first
GWBU through 14 temporary injection
points. A third in-situ chemical
oxidation event was completed April
2012. 120 gallons of a KMnO4 solution is
injected into the first GWBU
through 8 temporary injection points.

Results to date:
Sampling data shows site wide decreases in concentrations due to the in-situ chemical oxidation events. Concentrations of PCE have decreased between 50 and 80 percent over the course of the response action period. A similar decrease in the oncentrations of TCE and cis-
1,2-DCE has occurred during this same period. Groundwater monitoring data has indicated that the plume is not laterally mobile. Concentrations in other monitoring wells remain stable or are declining over the past several years.

Approximately 12 to 15 cubic feet of contaminated soil was removed from the site.

Next Steps:
Continuing a regular groundwater monitoring program to establish temporal trends in the groundwater monitoring data
and monitor the effectiveness of the groundwater response action.

Additional rounds of ISCO are also planned.

Cost to Design and Implement:
$78,000

Why the technology was selected:
Removal of the COCs will permanently eliminate concentration from leaching above the critical soil PCLs.

Date implemented:
June 2011

Final remediation design:
The final excavation limit was
8 by 10 feet to a depth of approximately
4 feet. The excavation was backfilled
with clean select fill, compacted, and
later resurfaced with concrete. The soil
was taken to an approved landfill.

Results to date:
Sampling data shows site wide decreases in concentrations due to the in-situ chemical oxidation events. Concentrations of PCE have decreased between 50 and 80 percent over the course of the response action period. A similar decrease in the oncentrations of TCE and cis-
1,2-DCE has occurred during this same period. Groundwater monitoring data has indicated that the plume is not laterally mobile. Concentrations in other monitoring wells remain stable or are declining over the past several years.

Approximately 12 to 15 cubic feet of contaminated soil was removed from the site.

Next Steps:
Onsite, 2 areas of contaminated soil remain below the existing dry cleaning facility. The dry cleaner operator has indicated a plan to ultimately complete the on-site construction of a new facility and demolish the existing dry cleaning facility. The remaining soil response action will be completed at that time.

Cost to Design and Implement:
$78,000