The U.S. Environmental Protection Agency’s (EPA) Water Infrastructure Resiliency and Finance Center, in collaboration with the ...
Adventus Americas, Inc. (AAI) announced the selection of its proprietary EHC-O product by a leading engineering consulting firm to remove high levels of petroleum volatile organic carbons (PVOCs) from groundwater at a site in Wisconsin. AAI's oxygen-releasing compound will be easily injected into a series of injection points using a Direct Injection method. The product will be mixed with water onsite into a slurry. The EHC-O content of the slurry will be varied to accomplish the desired injection volume, based on previous experience at the site.
"The remedial action at this site employed in-situ bioremediation that is facilitated by the use of an oxygen releasing compound to accelerate the aerobic biodegradation of petroleum volatile organic compounds of interest,” said Mark M. Mejac, senior hydrogeologist and project manager for STS Consultants, Inc., in Milwaukee, Wis. “We switched from an alternative oxygen releasing product to EHC-O as the source of controlled-release oxygen because of its ability to buffer pH effects and provide inorganic nutrients that are important to the biodegradation processes."
Dr. Jim Mueller, president of AAI, observed that, "Data to-date were promising, but overall performance was less than desired by the client. The source area had already been removed and the plume had partly been treated with an alternative oxygen-releasing product in October 2004. However, PVOCs were still detected at significant levels in down gradient monitoring wells during sampling events in February and May 2005. Although there are other oxygen-releasing products available on the market, there were very significant technical and cost advantages associated with the use of EHC-O."
EHC-O is part of Adventus Group's EHC brand umbrella, a family of latest generation bioremediation products used for the in situ treatment of groundwater and saturated soil impacted by heavy metals and persistent organic compounds such as chlorinated solvents, pesticides and energetics. The technology is a modification of its DARAMEND technology, which has been successfully used since 1992 to treat more than 800,000 tons of similarly contaminated soil, sediment and solid wastes.
EHC-O is an integrated source of slow-release oxygen, major-, minor-, and micro-nutrients, and a pH-buffering agent. This unique combination of materials facilitates the aerobic bioremediation of soils, sediment or groundwater environments impacted by various organic and inorganic compounds. For organic constituents amenable to aerobic biodegradation processes (e.g., petroleum hydrocarbons, certain pesticides/herbicides), EHC-O significantly stimulates the catabolic activity of the indigenous microflora, thereby accelerating the rate of contaminant removal.
The product is supplied in 30-pound pails as a powder, which can be mixed with soil or slurried in water. Installation techniques vary widely depending on the application. For example, the powder can be mixed with soil and placed at the bottom of an excavation where prior soil removal had been conducted. A slurry can be made and the mixture can be injected into the subsurface using techniques such as direct injection through Geoprobe rods or hydraulic fracturing. The powder is fine enough to permit injection of the slurry through well screens.