The EHC® PRB was installed as a line of direct push injection points across the width of the plume. Eight years after the installation the PRB is still supporting >90% reduction in inflowing CT concentrations and the downgradient plume has reduced significantly in size and concentration.
Groundwater emanating from a former grain storage area is impacted with carbon tetrachloride (CT). The CT plume extends approximately 2,500 ft (760 m) from a grain elevator where it discharges into a small creek. The CT source area is elusive and access restrictions due to residential housing further complicates source clean-up. Therefore, as an interim measure to prevent further plume migration, a permeable reactive barrier (PRB) was installed across the plume in April 2005. The PRB was created by injecting EHC®in situ chemical reduction (ISCR) compound in a line of direct push injection points installed along the first available roadway located downgradient from the source area. This project represents the first full-scale application of EHC into a flow-through reactive zone and the PRB has remained active for eight years now continuously supporting more than 95% removal of CT from groundwater, without accumulation of catabolites.