Remediation Status: In groundwater monitoring

Why the technology was selected:
Biostimulation and zero valent iron was chosen for the second phase of the remedial design in order to stimulate the reductive dechlorition that was occurring at the site. A different remedy other than chemical oxidation was chosen for the site based on insufficient dosages delivered to the subsurface.

Date implemented:
Summer 2007- Biostimulation and ZVI injections

Final remediation design:
Innovative Environmental Technologies Inc designed and implemented the subsequent injection event in Summer 2007 that was a mixture of abiotic and biotic technologies. 13 direct push injections were used to deliver 540 pounds of ZVI, 240 lbs of Calcium Propionate, 75 lbs of an oxygen scavenger, 180 lbs of nutrient, Vitamins B2 and B12, 500 pounds of HRC between 22 to 24 feet below ground surface.

Results to date:
PCE concentrations have decreased in MW-3 from the last sampling event in September 2008 from a concentration of 431 µg/L to 397 µg/L in February 2009. Concentrations of trichloroethene (TCE) have also decreased from the last sampling event in September 2008 from 19.1 µg/L to 13.7 µg/L during the last sampling event in February 2009. The concentrations of cis-1,2-DCE have decreased from 44.6 µg/L in September 2008 to 33.2 µg/L in September 2008. Vinyl chloride remains below the laboratory detection limit. In monitoring well MW-4, the concentration of PCE has decreased from the baseline of 397 µg/L in December 2005 and the historical high of 460 µg/L in April of 2006 to 5.08 µg/L in February 2009, which is just above the TN MCL for PCE. The total reduction of PCE in MW-4 is 99%. TCE concentrations remain below the laboratory detection limit as of the last three sampling events. Cis-1,2-DCE is below the statewide health standard with a concentration of 10.1 µg/L in February 2009, down from the historic high of 120 µg/L during the sampling event in March 2008. Vinyl chloride concentrations have increased in MW-4 from 66.2 µg/L in September 2008 to 122 µg/L in February 2009. The increase in the Vinyl Chloride is an indication that reductive dechlorination is still occurring biotically and that the present chlorinated solvents are continuing to be remediated. Reductive dechlorination appears to be occurring in both MW-3 and MW-4. Total PCE reduction in these two wells has been 20% and 99% respectively. In MW-3 concentrations of tetrachloroethane (PCE) have increased from 392ppb originally detected in sep-2003 to 397ppb in feb-2009. PCE has decreased from 558ppb in 12/07. Trichloroethane concentratons have increased from 3.8 ppb to 12.5 ppb from 9/03 to 3/08, but since the most recent injection event TCE concentrations have gone from 12.5 to 13.7 this increase is likley due to reductive dechlorination occuring. Also the increase in cis 1,2 DCE from 8ppb in 10/07 to 82.5 ppb in 9/08 confirm that reductive dechlorination is occuring in this monitoring point. In MW-4 PCE concentrations have gone from 471ppb in 9/03 to 5 ppb in 2.09, and since the most recent injection event PCE has dropped from 8.3ppb to 5ppb. The increase in cis 1,2 DCE from BDL in 9/06 to 120ppb in 3/08 and ultimatley 10ppb in 2/09 confirm continuous reductive dechlorination of the past year.

Cost to Design and Implement:
GW Remediation Cost- all technologies: $34,715.00

Why the technology was selected:
Chemical oxidation via permanganate injections was chosen based on the consultants recommendation.

Date implemented:
Fall 2005- Chemical oxidation Summer 2006- Chemical oxidation

Final remediation design:
The two permanganate injection events were conducted using direct push injections. The initial goal of the injection event was to inject 100 gallons of permanganate into each of the borings, however due to surfacing issues, the quantity of permanganate was decreased to 25 gallons.

Results to date:
PCE concentrations have decreased in MW-3 from the last sampling event in September 2008 from a concentration of 431 µg/L to 397 µg/L in February 2009. Concentrations of trichloroethene (TCE) have also decreased from the last sampling event in September 2008 from 19.1 µg/L to 13.7 µg/L during the last sampling event in February 2009. The concentrations of cis-1,2-DCE have decreased from 44.6 µg/L in September 2008 to 33.2 µg/L in September 2008. Vinyl chloride remains below the laboratory detection limit. In monitoring well MW-4, the concentration of PCE has decreased from the baseline of 397 µg/L in December 2005 and the historical high of 460 µg/L in April of 2006 to 5.08 µg/L in February 2009, which is just above the TN MCL for PCE. The total reduction of PCE in MW-4 is 99%. TCE concentrations remain below the laboratory detection limit as of the last three sampling events. Cis-1,2-DCE is below the statewide health standard with a concentration of 10.1 µg/L in February 2009, down from the historic high of 120 µg/L during the sampling event in March 2008. Vinyl chloride concentrations have increased in MW-4 from 66.2 µg/L in September 2008 to 122 µg/L in February 2009. The increase in the Vinyl Chloride is an indication that reductive dechlorination is still occurring biotically and that the present chlorinated solvents are continuing to be remediated. Reductive dechlorination appears to be occurring in both MW-3 and MW-4. Total PCE reduction in these two wells has been 20% and 99% respectively. In MW-3 concentrations of tetrachloroethane (PCE) have increased from 392ppb originally detected in sep-2003 to 397ppb in feb-2009. PCE has decreased from 558ppb in 12/07. Trichloroethane concentratons have increased from 3.8 ppb to 12.5 ppb from 9/03 to 3/08, but since the most recent injection event TCE concentrations have gone from 12.5 to 13.7 this increase is likley due to reductive dechlorination occuring. Also the increase in cis 1,2 DCE from 8ppb in 10/07 to 82.5 ppb in 9/08 confirm that reductive dechlorination is occuring in this monitoring point. In MW-4 PCE concentrations have gone from 471ppb in 9/03 to 5 ppb in 2.09, and since the most recent injection event PCE has dropped from 8.3ppb to 5ppb. The increase in cis 1,2 DCE from BDL in 9/06 to 120ppb in 3/08 and ultimatley 10ppb in 2/09 confirm continuous reductive dechlorination of the past year.

Cost to Design and Implement:
GW Remediation Cost- all technologies: $34,715.00

Why the technology was selected:
Biostimulation and zero valent iron was chosen for the second phase of the remedial design in order to stimulate the reductive dechlorition that was occurring at the site. A different remedy other than chemical oxidation was chosen for the site based on insufficient dosages delivered to the subsurface.

Date implemented:
Summer 2007- Biostimulation and ZVI injections

Final remediation design:
Innovative Environmental Technologies Inc designed and implemented the subsequent injection event in Summer 2007 that was a mixture of abiotic and biotic technologies. 13 direct push injections were used to deliver 540 pounds of ZVI, 240 lbs of Calcium Propionate, 75 lbs of an oxygen scavenger, 180 lbs of nutrient, Vitamins B2 and B12, 500 pounds of HRC between 22 to 24 feet below ground surface.

Results to date:
PCE concentrations have decreased in MW-3 from the last sampling event in September 2008 from a concentration of 431 µg/L to 397 µg/L in February 2009. Concentrations of trichloroethene (TCE) have also decreased from the last sampling event in September 2008 from 19.1 µg/L to 13.7 µg/L during the last sampling event in February 2009. The concentrations of cis-1,2-DCE have decreased from 44.6 µg/L in September 2008 to 33.2 µg/L in September 2008. Vinyl chloride remains below the laboratory detection limit. In monitoring well MW-4, the concentration of PCE has decreased from the baseline of 397 µg/L in December 2005 and the historical high of 460 µg/L in April of 2006 to 5.08 µg/L in February 2009, which is just above the TN MCL for PCE. The total reduction of PCE in MW-4 is 99%. TCE concentrations remain below the laboratory detection limit as of the last three sampling events. Cis-1,2-DCE is below the statewide health standard with a concentration of 10.1 µg/L in February 2009, down from the historic high of 120 µg/L during the sampling event in March 2008. Vinyl chloride concentrations have increased in MW-4 from 66.2 µg/L in September 2008 to 122 µg/L in February 2009. The increase in the Vinyl Chloride is an indication that reductive dechlorination is still occurring biotically and that the present chlorinated solvents are continuing to be remediated. Reductive dechlorination appears to be occurring in both MW-3 and MW-4. Total PCE reduction in these two wells has been 20% and 99% respectively. In MW-3 concentrations of tetrachloroethane (PCE) have increased from 392ppb originally detected in sep-2003 to 397ppb in feb-2009. PCE has decreased from 558ppb in 12/07. Trichloroethane concentratons have increased from 3.8 ppb to 12.5 ppb from 9/03 to 3/08, but since the most recent injection event TCE concentrations have gone from 12.5 to 13.7 this increase is likley due to reductive dechlorination occuring. Also the increase in cis 1,2 DCE from 8ppb in 10/07 to 82.5 ppb in 9/08 confirm that reductive dechlorination is occuring in this monitoring point. In MW-4 PCE concentrations have gone from 471ppb in 9/03 to 5 ppb in 2.09, and since the most recent injection event PCE has dropped from 8.3ppb to 5ppb. The increase in cis 1,2 DCE from BDL in 9/06 to 120ppb in 3/08 and ultimatley 10ppb in 2/09 confirm continuous reductive dechlorination of the past year.

Cost to Design and Implement:
GW Remediation Cost- all technologies: $34,715.00