Evaluation of Whey for Bioremediation of Trichloroethene Source Zones

ABSTRACT

The effectiveness of whey as an electron donor that stimulates bioremediation and enhances dissolution of trichloroethene (TCE) dense non-aqueous phase liquid (DNAPL) was investigated. Laboratory experiments were conducted to evaluate increased mass transfer of TCE from the DNAPL to the aqueous phase in abiotic batch microcosms amended with several concentrations of whey, and in abiotic columns using high- and low-concentration whey mixtures. The effective solubility of TCE was a factor of 6 higher in microcosms amended with 10% w/w whey compared to 1% w/w whey or nanopure water. Increased aqueous-phase concentrations of TCE were a function of both the concentration of whey and time. In the columns, a factor of 5 increase in TCE concentrations was observed in the effluent during amendment with 10% w/w whey compared to potable water and 1% w/w whey. A field study involving three whey injections was performed at a site that had been actively undergoing bioremediation in a residual source area using lactate for 5 years. Results of the field test show a factor of 3 increase in total molar concentrations of chloroethenes and ethene following injection of 10% w/w whey compared to 5% lactate. In addition, complete dechlorination of TCE to ethene continued.

KEYWORDS:

• bioremediation
• chlorinated solvent
• dechlorination
• DNAPL
• enhanced dissolution
• lactate
• TCE
• whey

ACKNOWLEDGMENTS

The authors wish to extend their gratitude to Dana Dettmers, Patrick Lebow, Kevin Harris, Kevin Hall, Reina Carroll, and Evan Myler for performing the field sampling at TAN; to Cathy Rae for performing chloroethene and organic acid analyses; and to Brad Blackwelder and Sandy Fox for performing the IFT analysis and column sampling. This work was funded by the U.S. Department of Energy office of environmental management.

Notes

^aNominal concentration as lactate.

^b w/w concentration.

^a The data presented in this table represent the average of three samples collected at corresponding days after three whey powder injections with one standard deviation from the mean.

^b The data presented in this table represent the average of two samples collected at corresponding days after two sodium lactate injections with one standard deviation from the mean.

^c Value is the ratio of the mean total molar concentration of VOCs and ethene during whey injections to the mean total molar concentration of VOCs and ethene during lactate injections.

^a The data presented in this table represent the average of three trials (n = 3 measurements/trial) and the standard deviation of those trials.