Whey powder as a cost-effective electron donor: Field demonstration

Whey powder is being evaluated as an electron donor for in-situ bioremediation (ISB) of chlorinated solvents in a trichloroethylene (TCE) residual source zone at Test Area North (TAN) located within the Idaho National Laboratory. This evaluation has progressed from a multi-year laboratory study to a field-scale pilot test. The focus of the pilot test is to confirm laboratory results, which suggested that whey powder may be a more cost effective electron donor that sodium lactate, which has been used during ISB operations at TAN since January 1999. Whey powder was recommended for a field-scale pilot test based on the laboratory studies because it enhances the dissolution of TCE DNAPL in column studies more than sodium lactate, has comparable dechlorination efficiency to sodium lactate, and is less expensive than sodium lactate per unit contaminant degraded. Whey powder is as easily distributed through a basalt-packed column as sodium lactate, indicating that similar injection volumes should result in similar distribution in the subsurface. The overall utilization rate of whey powder is higher than sodium lactate by over a factor of two. Whey powder enhances dissolution of TCE DNAPL into the aqueous phase to a greater extent than sodium lactate, which if confirmed in the field, could result in a reduction in operational timeframe of ISB at TAN. This is an abstract of a paper presented at the 8th International In Situ and On-Site Bioremediation Symposium (Baltimore, MD 6/6-9/2005).