Anaerobic Benzene Degradation in the Presence of Salinity

• Author / Creator

  Chan, Kelvin

• The environmental presence of benzene is mostly attributed to anthropogenic activities
  related to the oil and gas sector and industrial production. While intrinsic bioremediation with
  microbial organisms is an attractive remediation option due to its minimal maintenance, low cost,
  and non-intrusive nature, biodegradation progress is often stalled upon oxygen depletion in the
  subsurface. At such instances, the microbial community must shift towards anaerobic conditions
  and rely on other redox conditions (such as nitrate-, sulfate-reducing, and methanogenesis) without
  oxygen as a terminal electron acceptor. Furthermore, this situation is often compounded in the oil
  and gas industry with the release of produced water which contains not only benzene but is also
  highly saline. In this M.Sc. thesis, the concept in which salt is a co-contaminant to benzene is
  explored for bioremediation utilizing microbial cultures previously demonstrated to anaerobically
  biodegrade benzene.
  In the first phase of this experiment, the Culture Enrichment period, a benzene
  biodegrading baseline for the nitrate-, sulfate-reducing, and methanogenic cultures is established.
  Cultures derived from clay sediments were able to biodegrade benzene at a slightly higher rate
  (17.7 ± 10.2 µM/d) then the sand counterparts (14.9 ± 10.9 µM/d). In the second phase, the Salinity
  Experiment, salt contents of 0.0, 0.5, 1.0, and 2.0 g/L NaCl were explored. The nitrate-, sulfate-,
  and methanogenic treatments demonstrated benzene biodegradation rates of 1.8 ± 0.5, 4.2 ± 5.1,
  and 2.1 ± 3.4 µM/d respectively. Within a benzene feed concentration between 0.5 and 0.7 mM,
  biodegradation rates were consistently the highest within the 1.0 g/L NaCl conditions, suggesting
  this to be the optimal salt content to stimulate benzene biodegradation within this experiment.

• Subjects / Keywords

  • Sulfate-Reducing
  • Benzene
  • Anaerobic Degradation
  • Methanogenic
  • Methanogenesis
  • Nitrate-reducing
  • Salinity
  • Anaerobic Biodegradation
  • Microcosm

• Graduation date

  Fall 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-yvqz-fa71

• License

  Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.