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Biodegradability of Diluted Bitumen (Dilbit)

Deshpande, Ruta S
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470757897

Abstract Details

2016, MS, University of Cincinnati, Engineering and Applied Science: Environmental Engineering.
The share of unconventional fuel sources (oil sands, shale gas etc.) in the oil market is growing in terms of production and usage. For the past 40 years, the United States has been importing petroleum products derived from Canadian oil sands. Nevertheless, in recent times, owing to the increased demand, the proposal of pipeline expansions along with two major spills (Kalamazoo, 2010 and Mayflower, 2013), these sources are again in the limelight. Oil sands yield bitumen which is the heaviest form of crude oil. For transportation purposes, bitumen is altered either by diluting or upgrading. When bitumen is blended with lighter hydrocarbons, diluted bitumen or dilbit is produced. Its physical and chemical properties are quite different from those of conventional oils. Limited and inconsistent literature is available on the biodegradability of dilbit, thus the main aim of this research was to evaluate different aspects of its biodegradation to fill this knowledge gap. To achieve this goal various bench scale experiments were run in two phases. In phase one, two tests were carried out at 5 and 25 ºC in freshwater media with two types of dilbits, western Canadian select (WCS) and Cold Lake Blend (CLB). Cultures isolated from sediments obtained after the dredging operations on Kalamazoo River spill were enriched and used as the inoculum. The physical and chemical characteristics of WCS and CLB differed slightly, whereas their composition was significantly different from that of a conventional crude oil. The degradation rates obtained for both dilbits as well as the extent of their removal were comparable, with faster rates for the higher temperature. Phase two was a comparative study to assess biodegradation of dilbit and a conventional crude oil under several conditions. For this purpose, WCS dilbit and Prudhoe Bay Crude (PBC) were tested. Additionally, microbial consortia obtained from two different hydrocarbon contaminated sites were used to evaluate the effect of microbial enrichments. Prior to the experimental set up, cultures obtained from Kalamazoo River (KMZ) where enriched on dilbit at 5 (cryo) and 25 (meso) ºC, while culture isolated from Ohio River (AF) was enriched at only 25 ºC. Although observed rates of alkane, polycyclic aromatic hydrocarbon (PAH), and total extractable hydrocarbon (TEH) removal were similar for dilbit and conventional crude oil, the latter degraded to greater extent. All three consortia showed diverse microbial community structure which greatly influenced degradation potential with varying temperature. Although complete alkane removal was achieved in all the treatments, the metabolism of PAH and TEH varied. The KMZ meso culture was the most efficient consortium as it metabolized most of the PAHs along with the biomarker hopane. The AF culture exhibited distinct behavior at the two temperatures with a longer assimilation time at the colder temperature, which was not the case at the warmer temperature.
Pablo Campo, Ph.D. (Committee Chair)
Robyn N. Conmy, Ph.D. (Committee Member)
George Sorial, Ph.D. (Committee Member)
71 p.
Environmental Engineering
Oil sands; diluted bitumen; dilbit; biodegradation; Unconventional oil

Recommended Citations

Citations

  • Deshpande, R. S. (2016). Biodegradability of Diluted Bitumen (Dilbit) [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470757897

    APA Style (7th edition)

  • Deshpande, Ruta. Biodegradability of Diluted Bitumen (Dilbit). 2016. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470757897.

    MLA Style (8th edition)

  • Deshpande, Ruta. "Biodegradability of Diluted Bitumen (Dilbit)." Master's thesis, University of Cincinnati, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470757897

    Chicago Manual of Style (17th edition)

ucin1470757897
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This open access ETD is published by University of Cincinnati and OhioLINK.