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Bioreduction of Hexavalent Chromium in Flow-Through Quartz Sand Columns |
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| Authors: | Mahbub Alam Md Akram Hossain David R Yonge Brent M Peyton James N Petersen |
| Affiliation: | 1PhD Candidate, Dept. of Civil and Environmental Engineering, Center for Multiphase Environmental Research, Washington State Univ., P.O. Box 642910, Pullman, WA 99164-2910. E-mail: mahbub@mail.wsu.edu 2Associate Professor, Dept. of Civil and Environmental Engineering, Washington State Univ., Tri-Cities, 2710 University Dr., Richland, WA 99352 (corresponding author). E-mail: ahossain@tricity.wsu.edu 3Professor, Dept. of Civil and Environmental Engineering, Center for Multiphase Environmental Research, Washington State Univ., P.O. Box 642910, Pullman, WA 99164-2910. E-mail: yonge@wsu.edu 4Associate Professor, Dept. of Chemical Engineering, Center for Multiphase Environmental Research, Washington State Univ., P.O. Box 642710, Pullman, WA 99164-2710. E-mail: bmp@wsu.edu 5Vice Provost for Research, Washington State Univ., P.O. Box 641033, Pullman, WA 99164-1033. E-mail: jnp@wsu.edu |
| Abstract: | Hexavalent chromium (Cr(VI)) contamination of soil and groundwater is a major environmental concern for some industrial sites and most of the U.S. Department of Energy sites. Cr(VI) is toxic and fairly mobile in groundwater. Bioreduction of Cr(VI) to less toxic and less mobile Cr(III) is considered to be a feasible option. Among the Cr(VI) reducing bacteria, Shewanella oneidensis MR-1 (MR-1) has been shown to be effective in metal reduction under anaerobic conditions. Data on bioreduction of Cr(VI) by MR-1 in a flow-through soil column that better approximates the subsurface condition are not available. The objective of this research project was to study the bioreduction of Cr(VI) by MR-1 in a continuous-flow quartz sand column system. MR-1 was found to be very effective in reducing Cr(VI) to Cr(III) for concentrations ranging from 0.055 mM (2.85?mg/L) to 0.006 mM (0.31?mg/L). The amount of Cr(VI) reduced prior to its breakthrough was found to be inversely proportional to its concentration in the feed due to increased inhibition of microbial activity and a residual reduction of 20–45% of Cr(VI) was observed even after its breakthrough. |
| Keywords: | Biodegradation Bacteria Chromium Columns Environmental issues Microbes Sand |