Case Studies
EHC® Reagent | EHC® Liquid Reagent
In our projects at sites around the world, we show you how, once EHC® is injected into the subsurface, a series of physical, chemical, and microbiological processes create very strong reduction conditions that promote rapid and complete dechlorination of organic solvents and other recalcitrant compounds (e.g. explosives and organochlorine pesticides).
EHC® ISCR Reagent
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.
EHC® Reagent was evaluated for treatment of soil containing Volatile Organic Compounds (VOCs) and Organochlorine Pesticides (OCPs). The injections were conducted using hydraulic fracturing.
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 injected via direct push across the plume area impacted primarily by PCE and TCE.
The groundwater at a former unregulated solid waste management unit was impacted by various Chlorinated Volatile Organic Compounds (CVOCs), mainly chlorinated ethenes. In February 2006, EHC® Reagent was injected into the gravel trenches to convert them into permeable reactive barriers (PRBs).
EHC® in situ integrated biological and chemical reduction (ISCR) technology was used to treat Chlorinated Aliphatic Hydrocarbons (CAHs) safely, rapidly, and effectively at a manufacturing facility.
Following a truck accident on one of the main motorways in northern Italy, about 3,000 L of 1,2-dichloropropane was released into the ground, causing an immediate contamination of the soil and groundwater. 55,000 kg of EHC® Reagent was injected into a triangular grid of 42 injection points from one to six meters deep for contaminant remediation.
The first full-scale application of EHC® Reagent into a flow-through reactive zone was installed in 2005.
As featured in Journal of Environmental Monitoring, following a laboratory evaluation confirming treatability, EHC® Reagent was injected via direct push at a hot-spot area for treatment of Carbon Tetrachloride (CT) in groundwater. Application of a liquid EHC® formulation, composed of ferrous iron and a liquid organic carbon source, was also completed into the vadose zone.
EHC® Liquid Reagent
The objective of the project was to demonstrate the efficacy of EHC® Liquid injections for treatment of residual TCA and DCE contamination with limited access beneath the building and to reduce contaminant mass in the deeper saturated zone (20-25 ft bgs).
A relatively stagnant groundwater plume of PCE presents a vapor intrusion risk to the existing dry cleaning facility and adjacent businesses. Evidence of complete reductive dechlorination of PCE was observed over a relatively short time period and Dehalococcoides (Dhc) inoculation appears to have been successful.
Groundwater was impacted with chlorinated solvents (primarily PCE, TCE and 1,2-DCE). A pilot test was first conducted in November 2011 by injecting EHC® Liquid Reagent into the shallow aquifer. PCE and TCE concentrations were reduced to concentrations below the GWQS within 9 months following the pilot-scale treatment.
The objective of this pilot test was to demonstrate flux reduction of TCE downgradient of an EHC® Liquid Permeable Reactive Barrier (PRB). The flux calculations demonstrated a 73% reduction in 8 months. Advanced techniques such as real-time monitoring, microbial characterization and diagnostics and hi-res imaging were used to characterize and track remedial progress.