EHC® Reagent | EHC® Liquid Reagent

EHC® Liquid delivers proven PCE reduction even under difficult subsurface conditions. At the Millbrae dry‑cleaner site, the reagent was injected via direct push across a clay‑rich source zone with significant CVOC mass trapped in the smear zone. As featured in Remediation Journal, the controlled‑release carbon and organo‑iron chemistry helped overcome low permeability and long‑term sorption effects, accelerating reductive dechlorination within weeks.

EHC® Liquid delivered rapid, verifiable remediation results at a challenging dry‑cleaner site in Millbrae, California. Decades of PCE releases had created a persistent groundwater plume within low‑permeability clay and a heavily impacted smear zone. To address the full extent of contamination, EHC® was injected into a series of Permeable Reactive Barriers (PRBs) designed to treat the plume progressively over time. The controlled‑release carbon and organo‑iron chemistry quickly established strong reducing conditions, enabling complete reductive dechlorination. Within just six months, chlorinated solvent concentrations dropped by 99.7%, and all monitoring wells met groundwater cleanup criteria, demonstrating the effectiveness of EHC® Liquid for complex dry‑cleaner sites.

EHC® created a long‑lasting reactive barrier that reliably cut carbon tetrachloride (CT) migration at a challenging grain‑silo site in Kansas. Installed as a line of direct‑push injection points across the full plume width, the PRB immediately reduced CT mass flux and kept removal rates high even under complex geology and high groundwater flow. Twelve years later, the barrier is still achieving more than 90% reduction in inflowing CT, and the downgradient plume has shrunk dramatically in both size and concentration.

EHC® and KB‑1® were injected across the highest‑concentration TCE DNAPL zone—from 40 to 112 ft bgs—using direct push, as featured in Remediation Journal. Before treatment, dissolved‑phase levels reached 592,000 µg/L TCE and 90,000 µg/L cis‑DCE. The combined ISCR and bioaugmentation approach quickly established strong reducing conditions, driving rapid degradation. Within months, TCE concentrations fell below the DNAPL threshold, and several wells reached the U.S. EPA MCL, demonstrating effective remediation even in deep, high‑mass source zones.

As featured in Remediation Journal, hydraulic fracturing with EHC Reagent® was used to remediate TCE‑contaminated groundwater in low‑permeability, fine-grained sandstone at a former Atlas missile site in Colorado. By propagating a network of amendment‑filled fractures through the weathered bedrock, the project achieved broad subsurface contact and created strongly reducing conditions that support both abiotic and biological TCE degradation. Within two years, TCE mass was reduced by more than 90%, demonstrating that EHC® Reagent can effectively treat chlorinated solvents even in tight, difficult‑to‑access formations.

EHC® was injected via hydraulic fracturing into a weathered limestone source zone to treat soils impacted by VOCs and strongly sorbed OCPs at a former pesticide facility. Across four injection points, 43,590 lbs of reagent were placed, supported by sand‑enhanced fractures for improved distribution. Bench tests had already shown >97% OCP and >99% VOC reduction, and field sampling seven months later confirmed ~93% decreases in Toxaphene and total OCPs, demonstrating effective in situ treatment in a challenging, heterogeneous subsurface.

EHC® was tested in a bench‑scale system treating very high perchlorate levels (~100 mg/L). The reagent created strong reducing conditions that supported both abiotic and biotic degradation, achieving greater than 99% removal of perchlorate from groundwater. Concentrations dropped from 120,000 ppb to non‑detect, and chloride generation confirmed true destructive treatment. Performance remained fully effective for more than 1,200 days, and the system also removed TCE with minimal breakdown products—demonstrating long‑lasting, reliable treatment under high‑mass conditions.

This case study highlights how EHC® Reagent provided a fast, low‑disruption solution for treating a persistent PCE plume at a former dry‑cleaning site in Boulder, Colorado. After injecting 1,700 lbs of EHC into 18 points, groundwater monitoring showed a 99.8% reduction in PCE and contaminant levels dropping to non‑detect in nearly all wells within nine months, without accumulation of harmful catabolites such as DCE or VC. The approach combined targeted hot‑spot treatment with a permeable reactive barrier to address residual mass beneath the former building, offering clients a cost‑effective and regulator‑aligned path toward site closure.

EHC® Reagent was used to transform existing groundwater collection trenches into high‑performing permeable reactive barriers, providing a passive and cost‑efficient treatment solution for TCE, DCE, and VC. After injecting 11,850 lbs of EHC (with targeted KB‑1® bioaugmentation), the system achieved >99% reduction of CVOCs within the trenches and strong downgradient attenuation—without generating vinyl chloride. The PRBs remained effective for more than three years, giving the site owner a long‑lasting, low‑maintenance remedy that leveraged existing infrastructure.

EHC® Reagent was applied in two pilot‑scale PRBs to treat a complex mix of chlorinated ethanes, ethenes, and methanes in low‑permeability saprolite and partially weathered rock. Despite challenging hydrogeology and contaminant rebound, the injections created strong anaerobic zones that enabled rapid and sustained reductive dechlorination. Within eleven weeks, key CAHs dropped by up to 98%, and after 26 months, concentrations in both zones had decreased by up to 99%. The pilot demonstrated that the use of EHC® ISCR technology can reliably overcome difficult subsurface conditions and deliver robust, long‑term treatment performance.

A truck accident in northern Italy released roughly 3,000 L of 1,2‑dichloropropane into low‑permeability silty‑clay soils, causing significant soil and groundwater contamination. To remediate the residual plume, 55,000 kg of EHC® Reagent were injected across a 42‑point grid, supported by a recirculation system to enhance distribution. The amendment established long‑lasting reducing conditions in the tight formation, achieving >96% contaminant reduction and sustaining treatment for more than three years. This combined containment‑and‑ISCR/ERD approach met regulatory cleanup targets and enabled full site closure in 2015.

A long‑term field study from Kansas shows how an injected EHC® permeable reactive barrier (PRB) can sustain high treatment performance in a sulfate‑rich, high‑flow aquifer. This project was the first full-scale application of EHC® into a flow-through reactive zone and provided valuable information about substrate longevity and PRB performance over time. Installed in 2005, the barrier achieved >99% carbon tetrachloride removal within 16 months and maintained ~95% removal for more than 12 years, far beyond expectations. The case demonstrates how combined abiotic ZVI reactions and biotic degradation can prolong treatment even after the organic carbon is consumed.

A Kansas pilot test showed that modified EHC® Reagent can sharply reduce carbon tetrachloride (CT) in a concentrated hotspot. 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. The combined ZVI and carbon source quickly created strong reducing conditions, driving fast CT breakdown with minimal accumulation of intermediates.

A Denver industrial site used EHC® Liquid to treat residual TCA and DCE beneath an active building where access was highly restricted. The objective of the project was to demonstrate the efficacy of EHC® Liquid injections for treatment of residual TCA and DCE contamination beneath the building and to reduce contaminant mass in the deeper saturated zone (20–25 ft bgs). By using the former source‑area excavation as a subsurface reaction vessel and extracting groundwater downgradient, the injections successfully established strong, long‑lasting reducing conditions that drove CVOC degradation under the building.

A pilot test at a dry cleaner in Millbrae, California applied EHC® Liquid to accelerate reductive dechlorination in a stagnant PCE‑impacted groundwater plume posing vapor‑intrusion risks. Based on the analytical results from bio samplers with various amendments, EHC® Liquid Reagent was selected as the remedial approach for the pilot study injection test. The combined controlled‑release carbon and organo‑iron formulation, together with Dehalococcoides (Dhc) inoculation, quickly established reducing conditions and drove a marked decrease in PCE and daughter products within weeks.

A pilot test at a former industrial site in Holmdel, New Jersey applied EHC® Liquid to address groundwater impacted with PCE, TCE, and 1,2‑DCE. The injected amendments were successful at establishing long‑lasting, highly reducing conditions conducive to chemical and biological reduction of cVOCs. A blend of controlled‑release carbon, organo‑iron, buffering agent, and Dhc culture was injected across the shallow aquifer, targeting impacts from 7–21 ft bgs. Within nine months, PCE and TCE concentrations in monitoring wells declined to below groundwater standards, confirming effective biotic and abiotic treatment.

A pilot test at a former manufacturing facility in New Jersey installed an EHC® Liquid PRB to reduce TCE flux in a high‑concentration plume. The objective was to demonstrate measurable flux reduction downgradient of the barrier, achieving a 73% decrease within eight months while using real‑time monitoring, microbial diagnostics, and high‑resolution imaging to track performance. The balanced carbon–iron chemistry established strong reducing conditions, and advanced diagnostic tools confirmed both contaminant destruction and effective amendment distribution across the treatment zone.