Title page for etd-0707115-141228


[Back to Results | New Search]

URN etd-0707115-141228
Author Wei-Hsiang Huang
Author's Email Address No Public.
Statistics This thesis had been viewed 5345 times. Download 0 times.
Department Environmental Engineering
Year 2014
Semester 2
Degree Ph.D.
Type of Document
Language zh-TW.Big5 Chinese
Title Application of Enhanced Sulfate Reduction Method to Remediate Petroleum-hydrocarbon Contaminated Groundwater
Date of Defense 2015-07-27
Page Count 140
Keyword
  • groundwater contamination
  • sulfate reduction
  • petroleum hydrocarbon
  • releasing materials
  • enhanced bioremediation
  • Abstract Groundwater at many existing or former industrial areas and underground storage tank sites is contaminated by petroleum hydrocarbons. The purpose of this study was to develop a passive enhanced sulfate reduction system to treat the methyl tertiary-butyl ether (MTBE), benzene, and toluene contaminated groundwater. A sulfate-releasing material was developed for long-term sulfate releasing for sulfate supplement. Microcosm study was performed to evaluate the contaminants (e.g., MTBE, benzene, toluene) removal efficiency under sulfate reducing conditions. A column experiment was applied to evaluate the effectiveness and mechanisms of sulfate reduction processes on the bioremediation of benzene, toluene, and MTBE contaminated groundwater. The denaturing gradient gel electrophoresis (DGGE) and DNA sequencing methods were also applied to determine the microbial diversity and dominant bacteria under sulfate reducing conditions. Results from the microcosm study show that the ORP dropped to below -150 mv after initial oxygen consumption. Sulfate reduction was activated when the oxidation-reduction stage reached anaerobic conditions. Results show that the removal efficiencies for toluene, benzene, and MTBE were 90, 63, and 8%, respectively. The sulfate reduction process was inhibited after the sulfate was consumed. The production of sulfide also caused the inhibition of the sulfate reduction process. In the experiment with Cu(II) addition, the removal efficiencies for toluene and Cu(II) were 99 and 100%, respectively. Results also show that the formation of Cu precipitate was observed due to the reaction of Cu and sulfide. This would result in the reduction of toxicity effect caused by the sulfide. In the sulfate releasing experiment, the sulfate release rates were -1.46×10-2 and -2.18×10-2 in starch and rice husk groups, respectively. The total amount of sulfate release reached 70%. In the column experiment with sulfate addition, simulated anaerobic groundwater containing benzene, toluene, and MTBE (average concentration = 20 mg/L) was pumped into the system at a flow rate of 0.36 mL/min. Sulfate (used as the electron acceptor) was injected into the system to activate the sulfate reducing process. Anaerobic sludge collected from an anaerobic basin of an industrial wastewater treatment plant was inoculated into the system to enhance the sulfate reduction rate. Up to 92, 65, and 45% of toluene, benzene, and MTBE removal efficiencies were observed with the first-order decay rate of 34, 1.8, and 1 1/d, respectively. Results indicate that toluene is more biodegradable under sulfate reducing conditions compared to benzene and MTBE, and 0.7 g/L of sulfate consumption was observed during the biodegradation process. The occurrence of sulfate reduction can be confirmed by the increased sulfide (increased from 7 - 9 to 340 - 520 mg/L) and ferrous iron (increased from <0.1 to 52 mg/L then dropped to 0.14 mg/L due to the formation of iron sulfide) concentrations. In the latter part of this study, accumulation of hydrogen sulfide caused the microbial inhibition, and thus, decreased contaminant removal efficiencies were observed. The microbial communities were characterized by 16S rRNA-based DGGE profiling for soils in the system. Results show that sulfate addition could result in the enhancement of sulfate reducer growth, and thus, sulfate reduction became the dominant biodegradation process. A total of 39 different petroleum-hydrocarbon degrading bacteria were observed under the sulfate-reducing conditions. Results indicate that the sulfate reduction has the potential to be developed into a practically and economically acceptable technology to remediate petroleum-hydrocarbon contaminated groundwater.
    Advisory Committee
  • Guor-Cheng Fang - chair
  • Rao Y. Surampalli - co-chair
  • Cheng-Di Dong - co-chair
  • Ching-Yuan Chen - co-chair
  • Ku-Fan Chen - co-chair
  • Chin-Ming Kao - advisor
  • Files
  • etd-0707115-141228.pdf
  • Indicate in-campus at 99 year and off-campus access at 99 year.
    Date of Submission 2015-08-14

    [Back to Results | New Search]


    Browse | Search All Available ETDs

    If you have more questions or technical problems, please contact eThesys