Remediation Status: Site closed

Why the technology was selected:
In-situ chemical oxidation (ISCO) was selected because it does not require expensive pump systems, can treat area without disturbing aboveground structures, and does not require excavation and disposal of contaminated soils. The response action also compliments the natural attenuation processes to provide long term stability within the contaminant plume. NaMnO4 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:
April 2009

Final remediation design:
A dosage of 150 pounds per foot (lbs/ft) for 3DMe and 3.0 lbs/ft for HRC Primer. The dosage for 3DMe is based on an 11:1 dilution ratio. The biostimulation injection borings were advanced using a Geoprobe® 6620DT direct-push rig. Prior to boring at each injection location, a customized 1-ft long injection rod was attached to the first Geoprobe® probing rod and probed to the bottom of the GWBU at approximately 20 ft BGS. The emulsion was pumped into the formation at an approximate flow rate of 2 to 3 gallons per minute and an injection pressure of less than 100 pounds per square inch gauge.

Results to date:
Natural attenuation evaluation revealed that reductive dechlorination is occurring based on favorable geochemical conditions and detection of PCE daughter products (e.g. TCE,DCE and VC).

Cost to Design and Implement:
$73,308.55

Why the technology was selected:
In-situ chemical oxidation (ISCO) was selected because it does not require expensive pump systems, can treat area without disturbing aboveground structures, and does not require excavation and disposal of contaminated soils. The response action also compliments the natural attenuation processes to provide long term stability within the contaminant plume. NaMnO4 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:
April 2009

Final remediation design:
Five pails (285 pounds) of RemOx® L In Situ Chemical Oxidation (ISCO) reagent sodium permanganate (NaMnO4) (39.50 - 41 percent (%) solution) were shipped to Joyce Cleaners site for ISCO. The NaMnO4 solution was prepared by mixing one pail (57 pounds) of NaMnO4 with 40 gallons of potable water in a holding drum to attain approximately 5% NaMnO4 solution. This procedure was repeated four additional times. Injection locations were selected based on results of the February 2009 groundwater sampling event. Five injection points were advanced by a truck-mounted GeoProbe® using a direct-push hollow-probe rod assembly to a predetermined depth of 20 feet below grade level (bgl). The diluted NaMnO4 solution was pumped into the shallow saturated zone interval between 16 and 20 feet bgl using a Moyno pump through the hollow probe rod. Approximately 225 gallons of diluted NaMnO4 solution were injected through the five injection points (approximately 45 gallons of diluted NaMnO4 solution per injection point).

Results to date:
Natural attenuation evaluation revealed that reductive dechlorination is occurring based on favorable geochemical conditions and detection of PCE daughter products (e.g. TCE,DCE and VC).

Cost to Design and Implement:
$73,308.55