Sami A. Fam, Ph.D., P.E. L.S.P., Innovative Engineering Solutions, Inc., Sam Fogel, Ph.D., Bioremediation Consulting Inc.

Increased regulatory attention to 1,4 Dioxane and the development of clean-up goals are driving the need for a new, more cost effective in-situ technology for 1,4 Dioxane remediation. The chemical, a common stabilizer for 1,1,1 TCA does not respond well to traditional technologies such as carbon adsorption or air stripping and the most common treatment method for 1,4 Dioxane contaminated groundwater, ex-situ treatment using UV-hydrogen peroxide oxidation, is very expensive.

We have cultured a propanotroph (SL-D), an organism that can utilize propane as a sole carbon source, from one of our project sites in Salt Lake City, Utah.  SL-D can aerobically degrade a minimum of 10 mg/L of 1,4 Dioxane within hours.  We are currently evaluating the extent to which microorganisms like SL-D are present at other project sites, and the extent to which the 1,4 Dioxane is utilized for growth by the organism. We are currently conducting genetic testing on the organism and will present the results in the paper.

We have conducted several microcosm experiments in growing and culturing the organism followed by repeated feeding of 1,4 Dioxane. The SL-D propanotroph tends to only degrade the 1,4 Dioxane after the propane has been partially/mostly consumed after which point the Dioxane is rapidly convereted to carbon dioxide.

The SL-D culture is currently available for potential bioaugmentation in full-scale applications. We have also developed techniques for the enrichment of native propanotrophs and engineered a safe and reliable dissolved propane subsurface delivery system. The delivery systems are focused on solubilizing the propane in recirculated groundwater.