Southern Indiana Manufacturing Facility

A synergistic integration of anaerobic enhancement and zero valent iron was applied at a manufacturing facility in Southern Indiana. Contaminants including tetrachloroethene (PCE), trichloroethene (TCE), cis-1,2-dichloroethene (cis-1,2-DCE), trans-DCE, and vinyl chloride were present.

The geology consisted of an extremely tight glacial till underlain with bedrock. The bulk of the contamination was dissolved phase material within the soil bedrock interface.

A pilot scale application was completed over an area of approximately 8,000 square feet to demonstrate the efficacy of the reductive dechlorination technologies employed. The injection program targeted the predominant silty clayey sand between 10-12 feet below ground surface. A total of 24 injections at depths between 10-12 feet bgs and 13-15 bgs were performed while the facility was in operation.

The injection program utilized direct-push technology to apply vitamins (B12, B2), essential nutrients (o-PO₄⁺ and NH₄⁺), sodium sulfite, calcium propionate, yeast extract, zero-valent iron (ZVI), and hydrogen release compounds (HRC-X and HRC).

The objectives of the program were to establish and maintain a stable dissolved hydrogen level, provide micro-nutrients, maintain pH, provide for optimal competitive conditions for the desired microbial consortia while minimizing the impact to the day-to-day operations of the facility (U.S. Patent 7,129,388).

The stimulus of these indigenous bacteria in the subsurface, in conjunction with the ZVI component, is utilized to effect the rapid and measurable removal of the targeted compounds in the groundwater and saturated soils.

The increase in concentrations of cis-1,2-DCE confirmed that the reductive dechlorination process was actively taking place in the subsurface. A full-scale design for the entire facility was developed following successful pilot results.