Title page for etd-0718115-165801


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URN etd-0718115-165801
Author Chen Hsu
Author's Email Address No Public.
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Department Environmental Engineering
Year 2014
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Development of long-lasting pH buffered colloidal substrate to remediate TCE-contaminated groundwater
Date of Defense 2015-07-24
Page Count 116
Keyword
  • buffered colloidal substrate
  • Molecular biological tool
  • trichloroethylene
  • Bioremediation
  • saturated zone
  • Abstract Soil and groundwater at many existing and former industrial areas and disposal sites are contaminated by halogenated organic compounds that were released into the environment. When they are released into the subsurface, they tend to adsorb onto the soils and cause the appearance of DNAPL (dense-non-aqueous phase liquid) pool. The trichloroethylene (TCE) has been shown on induces hepatocellular carcinogens in mice and is a human carcinogen. Thus, TCE was used as the target compound in this study. As contaminated groundwater moves through the emplaced reactive zones, the contaminants are removed, and uncontaminated groundwater emerges from the downgradient side of the reactive zones. Application of in situ anaerobic bioremediation is a feasible technology to remediate DNAPL site. However, enhanced in situ bioremediation requires the injection of primary substrates, which would cause the acidification and odor problems of the subsurface environment. This would deteriorate the groundwater quality and cause the increase in maintenance cost. The objective of this proposed study is to develop buffered colloid substrate (BCS). The BCS can be applied in the saturated zone, which can release substrate from the colloid to enhance the reductive dechlorination of DNAPL in the saturated zone. Furthermore, the buffered colloid has the capability for pH control and prevents the decrease in pH value in groundwater. In this study, batch experiments were operated to test the feasibility of using BCS as the slow-released substrate and acidification control material. Several experimental conditions included the concentrations of contaminants and substrates, shacking speed, percentage of each component, acidification test, and molecular biotechnology. Results show BCS emulsion stability can reach 100% after place one day and no stratification for 96 days. Addition of BCS diluted 60-fold monitoring 45 days, the remaining residual amount of total organic carbon in water most about 24% can continue to serve as a carbon source of needed microorganisms, and a pH of about 8.7 dechlorination of important beneficial bacteria growth. Results from the microcosm study indicate that the addition of BCS would enhance the biodegradation rate of TCE under anaerobic conditions. Approximately 85% of TCE could be removed when BCS was added in the system. Increase in dehalococoides (DHC) population was observed after the addition of BCS. Results will be useful in designing a field-scale system to enhance the in situ bioremediation of chlorinated-solvent contaminated groundwater.
    Advisory Committee
  • Jong-Kang Liu - chair
  • Shu-Hao Liang - co-chair
  • Lei yang - co-chair
  • Chil-Ming Kao - advisor
  • Files
  • etd-0718115-165801.pdf
  • Indicate in-campus at 99 year and off-campus access at 99 year.
    Date of Submission 2015-08-18

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