The site consists of inter-bedded shale and siltstone bedrock.
Targeted Environmental Media:
 Dense Non-aqueous Phase Liquids (DNAPLs) - Fractured Bedrock
Not identified in the references cited.
Major Contaminants and Maximum Concentrations:
- Tetrachloroethene (100 µg/L)
No technologies selected.
- Chemical Oxidation (In Situ)
Comments:
In situ chemical oxidation (ISCO) treatments targeted primary fracture migration pathways, focusing on a suspected dense nonaqueous phase liquid (DNAPL) source zone for mass treatment. Groundwater recirculated with permanganate amendment prevented off-site migration of permanganate, while distributing the permanganate throughout treatment area. Permanganate waste and consumption was minimized through the use of pulsed injection followed by rebound monitoring in targeted rebound areas.
Not identified in the references cited.
Permanganate was effectively distributed over a wide area. Substantial mass destruction was demonstrated by chloride concentration increases to 1,000 milligram/liter (mg/L). Over 1,350 pounds (lbs) of TCE have been destroyed, as well as 945 lbs of DNAPL/sorbed mass. A theoretical pump and treat system removing 2 mg/L TCE and running at 20 gallons per minute, would need to run for 110 years and would extract 10.5 million gallons of water per year to achieve the same results.
ýIt is important to understand contaminant migration pathways.
ýTreatment is labor intensive.
ýActual mass of permanganate required was greater than what was estimated.
ýPhased injections allow for: (1) assessment of rebound potential; (2) detection of DNAPL areas through the use of parent to daughter dechlorination ratios; (3) more focused treatment, lowering groundwater issues and costs through targeted permanganate application.
ýAnticipate contaminant rebound; therefore, plan for multiple injections.
ýIt is unlikely that this process will allow cleanup to maximum contaminant levels (MCL).
References:
Konzuk, Julie; Suzanne OýHara; Karen Berry-Spark; Mark Watling; and Evan Cox. 2010. Lessons Learned from Full-Scale Implementation of In Situ Chemical Oxidation in Fractured Bedrock. From Seventh International Conference on Remediation of Chlorinated and Recalcitrant Compounds, May 2010, Monterey, CA.
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