Perchlorate is a groundwater contaminant that is highly mobile and persistent in the environment. Current research indicates that both abiotic and biotic mechanisms support removal of perchlorate from groundwater. A bench-scale treatability study showed that greater than 99% removal of perchlorate from groundwater was achieved with EHC® Reagent, promoting both abiotic and biotic treatment mechanisms.
EHC® Reagent
Perchlorate, Chlorinated Solvents
A column was filled with a mixture of EHC (24% by mass) and sand. This column was designed to mimic a permeable reactive barrier trench filled with a mixture of the reactive material (EHC) and sand. The column was followed by two downstream attenuation microcosms, which were filled with soil, to monitor any further reduction of perchlorate that may occur down gradient of the reactive zone. A control system was also set up as described above, except no EHC was added to the column. The Results of this bench study, which ran for over three years, indicates that EHC is capable of consistently treating greater than 99% of perchlorate, while simultaneously treating chlorinated solvents.
As featured in Remediation Journal, EHC Reagent was injected via direct push across the source area. Site specific challenges included a low permeability clayey lithology and a large degree of CVOC mass sorbed at the smear zone due to large variations in the groundwater table.
EHC was injected into a series of permeable reactive barriers (PRBs) across the plume with the goal to treat the entire plume area over time. After only 6 months CT concentrations were reduced by 99.7%, with all monitoring wells meeting the groundwater clean up criteria.
The EHC® PRB was installed as a line of direct push injection points across the width of the plume. Twelve 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.
As featured in Remediation Journal, EHC® Reagent and KB-1® Bioaugmentation Culture were injected across the highest concentration area from approximately 40 to 112 ft bgs using direct push. Prior to treatment dissolved phase concentrations ranged as high as 592,000 and 90,000 μg/L for TCE and cis-DCE, respectively.
As featured in Remediation Journal, EHC Reagent was emplaced via hydraulic fracturing into fine-grained sandstone to remediate TCE in groundwater.