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ETD RECORD
Optimization of enhanced in situ bioremediation of a TCE residual source area derived from integration of laboratory studies with field operations
Citation
Macbeth, Tamzen Wood.. (2008). Optimization of enhanced in situ bioremediation of a TCE residual source area derived from integration of laboratory studies with field operations. Theses and Dissertations Collection, University of Idaho Library Digital Collections. https://www.lib.uidaho.edu/digital/etd/items/etd_242.html
- Title:
- Optimization of enhanced in situ bioremediation of a TCE residual source area derived from integration of laboratory studies with field operations
- Author:
- Macbeth, Tamzen Wood.
- Date:
- 2008
- Keywords:
- In situ bioremediation--Idaho--Snake River Plain Aquifer Trichloroethylene--Cleaning--Idaho--Snake River Plain Aquifer Pollution--Idaho--Snake River Plain Aquifer
- Program:
- Civil Engineering
- Abstract:
- The treatment of a residual source of trichloroethene (TCE) contamination within the Snake River Plain Aquifer (SRPA) at Test Area North (TAN) using enhanced in situ bioremediation (EISB) has resulted in effective degradation of contaminants since 1999. Regular injections of sodium lactate stimulated the indigenous microbial community, and effectively created the conditions necessary to degrade aqueous phase TCE to ethene within the treatment area. Operations for EISB included an initial field evaluation to determine if EISB was a viable remedy for the TAN contaminant area, application of EISB as the remedy of choice at TAN, and most recently, optimization of operations applying EISB. Similar to many contaminated sites containing residual or dense non-aqueous phase liquids (DNAPL), the greatest limitation to remedial performance is the dissolution of the residual phase material into groundwater, where it is available for biodegradation. Therefore, laboratory and field studies were designed and executed in order to evaluate bioremediation substrates that might be more effective based on their physical, chemical and/or biological properties including: (1) ability to enhance mass transfer of TCE DNAPL, (2) effectiveness for stimulating contaminant degradation, and (3) pH and microbiological impacts.;Laboratory studies indicated that whey powder was superior to sodium lactate in meeting the objectives described above and was selected for a field pilot test to compare the effectiveness of sodium lactate with whey. Similar to the laboratory studies, whey enhanced mass transfer of TCE from the residual source to groundwater by a factor of 3 to 6 compared to sodium lactate and stimulated efficient reductive dechlorination of TCE to ethene. Fermentation of the primary substrate in whey, lactose, reduced pH to less than 5.5, which reduced dechlorination efficiency. The high buffering capacity of the TAN aquifer, however, mitigated pH effects, and overall, efficient reductive dechlorination was achieved. In addition, acetate-utilizing methanogens, and not hydrogen-utilizing methanogens, which compete for dechlorinating bacteria for hydrogen were enriched and maintained using both sodium lactate and whey. The higher rate of mass dissolution and subsequent biodegradation using whey powder will substantially reduce the longevity of the residual source at TAN.
- Description:
- Thesis (Ph. D., Civil Engineering)--University of Idaho, April 2008.
- Major Professor:
- Steven Porter.
- Defense Date:
- April 2008.
- Type:
- Text
- Format Original:
- xiii, 141 leaves :col. ill. ;29 cm.
- Format:
- record
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- In Copyright - Educational Use Permitted. For more information, please contact University of Idaho Library Special Collections and Archives Department at libspec@uidaho.edu.
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