Combining Remedial Technologies and Implementation Methods to Address Chlorinated Solvent Impacts at Complex Sites
Complex sites require complex solutions. Challenges typically include heterogeneous geology and contaminant mass distribution, vadose and/or saturated contaminant mass, and concentrations that span several orders of magnitude. These require us as practitioners to often consider multiple remedial technologies and approaches to reach the site specific goals within the desired timeframes. Often technologies are inefficiently implemented sequentially; this extends the remediation timeframe and requires re-characterization between remedial phases. This presentation will highlight several projects where multiple technologies were successfully implemented in concert. The strategies for each site included different approaches for source and plume remediation.
Site #1: An industrial property utilized chlorinated solvents for equipment maintenance from the 1950’s to 1970’s. Past operations resulted in multiple source areas and it is suspected that chlorinated solvents were discharged to drain pipes into a former settling pond. TCE concentrations have been detected in groundwater at a maximum concentration of 730 mg/L and in soils up to 6,800 ug/g. Soil blending was performed utilizing chemical oxidation (sodium permanganate) to treat the unsaturated TCE impacts exceeding an average 1,100 ug/g. BOS 100® was injected into the saturated zone in a barrier configuration to limit the mass flux from the source area and prevent contamination from leaving the subject property.
Site #3: A buried drum of TCE was discovered during site redevelopment. In situ chemical oxidation via potassium permanganate was used to successfully treat the source area. Downgradient of the source a permeable reactive barrier was installed via direct push injection in order to decrease the mass flux of the plume encroaching into a wetlands. Data will be presented from the source remediation as well as from the monitoring wells up and downgradient of the barrier.
Mike Mazzarese, AST Environmental Inc.