Pilot E-Redox™ (I) Systems at TCE- and 1,4-D-impacted Sites in Utah and Eastern USA

A field pilot test was conducted at a chlorinated solvent-contaminated site located in Utah, where TCE, DCEs, and vinyl chloride are the primary contaminants of concern. The E-Redox™ (I) system was applied to groundwater sediments, and results indicated enhanced back diffusion, which would result in high reduction rates indicated by high production of ethene. After 47 days, the ethene production was 15 times higher than the baseline concentration, which resulted in equivalent TCE and DCEs reduction rates of 1187 and 876 μg/L/day, respectively.

E-Redox™ (I) was applied at a former adhesive bond plant in eastern USA. The primary groundwater contaminants of concern were chlorinated VOCs and 1,4-dioxane (1,4-D). During operation, the reduction of chlorinated VOCs was confirmed by the detection of acetylene in groundwater. Acetylene is a highly unstable compound in groundwater, but it is also the most important fingerprint compound for abiotic beta-elimination of chlorinated VOCs. The detection of acetylene in several sampling events confirms that the implementation of E-Redox™ (I) technology has facilitated beta-elimination, a “cleaner” destruction of compounds such as TCE without DCEs and VC accumulation. This is further confirmed by the increased amount of ethene (from 1.8 to 71 micrograms per liter per day (μg/L/day)) in the groundwater, equivalent to TCE being completely reduced at rates from 8.2 to 335μg/L/day; or DCEs being completely reduced at rates from 6.0 to 247μg/L/day.

Decreasing 1,4-dioxane concentrations were observed partially due to anodic oxidative reactions from the generation of hydroxyl radicals.  The stimulation of microbial activity in the E-Redox™ (I) induced electrical field may also have contributed to the degradation of 1,4-D. 

An E-Redox™ (I) System for Reducing Nitrate in Groundwater (Lab Study)

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A Pilot E-Redox™ (I) System at a Perchlorate-impacted Site in Western USA

The E-Redox™ (I) technology was implemented in a remote location in western USA. The primary groundwater contaminant at this site was perchlorate. Solar power was utilized as a renewable electrical source for the E-Redox™ (I) system. During the operation of the E-Redox™ (I) system, substantial decreases in perchlorate concentrations were observed after a period of perchlorate back-diffusion and stabilized high concentrations. A parallel laboratory study was conducted by using groundwater from the site. The laboratory E-Redox™ (I) system maintained a stable current output by a DC-power supply. Results show that up to 53% of perchlorate was reduced within 40 hours in groundwater that also contained nitrate and sulfate. The test results indicate preferential reduction of nitrate and sulfate and it is expected that the perchlorate reduction rate would increase after complete reduction of the nitrate and sulfate. 

An E-Redox™ (I) System at a PAH-impacted Site in Eastern China

A field pilot test was conducted at a PAH-contaminated industrial site located in eastern China, where previous applications of chemical oxidants were not effective in reducing PAH concentrations. The E-Redox™ (I) system was applied to soils containing high concentrations of PAHs. After a treatment period of 12 days, results show ~79% decrease in naphthalene and >50% removal of total PAHs. Data also indicated the cleavages of higher polyaromatic rings and a trend of tentative shift towards compounds of less recalcitrance such as naphthalene.