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A former manufacturing facility in New Jersey was contaminated with 1,1-dichloroethylene (1,1-DCE) and 1,4-dioxane in a fractured bedrock aquifer. The previous treatment approach utilized a pump and treat method that was successful at containing and reducing contaminant concentrations within the source area, but the associated off-site transportation and disposal of recovery water was expensive.
Historic concentrations for 1,1-DCE within the source area ranged from 43-580 μg/L, and concentrations outside of the immediate source area persisted at low levels above Ground Water Quality Standards. 1,4- dioxane concentrations within the source area peaked at 580 μg/L.
PersulfOx in situ chemical oxidation (ISCO) was selected as a lower-cost alternative to the pump and treat method and also as a way to address the diffuse contamination surrounding the immediate treatment area. After application of PersulfOx, both 1,1-DCE and 1,4-dioxane concentrations within the source area rapidly decreased below detection levels and remained non-detect. In addition, the low levels of 1,1-DCE surrounding the original treatment area were also reduced to non-detect. Quarterly groundwater sampling will continue to track treatment performance.
PersulfOx is a sodium persulfate-based chemical oxidation technology that destroys both hydrocarbon and chlorinated solvent contaminants in the subsurface. PersulfOx contains a built-in catalyst that activates the persulfate component and generates contaminant-destroying free radicals without the need for the addition of a separate activator.
Application of PersulfOx resulted in the rapid reduction of source area 1,1-DCE and 1,4-dioxane concentrations to below detection limits. Low concentrations of 1,1-DCE surrounding the original treatment area were also reduced to non-detect. The concentrations of contaminants in both areas have remained below groundwater quality standards, meeting site requirements.