Bioremediation of oil sands process affected water sourced naphthenic acid fraction compounds

  • Author / Creator
    Miles, Sarah, M
  • Current development of Alberta’s oil sands region requires large volumes of water, leading to an abundance of oil sands process affected water (OSPW). OSPW contains naphthenic acid fraction compounds (NAFCs) which have been found to contribute extensively to OSPW toxicity. Degradation of this complex group of organics is key to the remediation of OSPW and thus is often the focus of research. This remediation study conducted microcosm experiments to elucidate and characterize the capacity of OSPW sourced fungus T. harzianum to degrade labile commercial NAs (Merichem), and OSPW-sourced NAFCs, and two model NA compounds, cyclohexane carboxylic acid (CHCA) and 1-adamanatane carboxylic acid (ADA). This proof of concept experiment confirms that the fungal species T. harzianum can contribute to the biodegradation of complex dissolved organics found in OSPW, including cyclic and diamondoid structures.
    As advanced oxidation processes have a proven capability for NAFCs remediation, and it has been demonstrated that microbial communities native to OSPW have the potential for biodegradation, coupling of these two processes would be an effective remediation strategy. Survivability of the native microbial community through the chemical treatment step in multi-step process is not well understood or researched with UV photocatalysis with TiO2. A multistep treatment approach coupling biological degradation with UV photocatalytic oxidation is the focus of this research, with nutrient addition to boost the native community’s degradation capacity. Step one being nutrient addition to stimulate the native microbial community, step two being UV photocatalytic oxidation, and a third step of nutrient addition to allow the surviving native microbial community the best conditions for biodegradation of organics produced in step two. Analysis showed that OPSW is limited in phosphorus (below detection limit of study analysis), and the addition of phosphorus improves degradation of otherwise thought recalcitrant NAFCs present in OSPW. Two treatments throughout the multistep treatment received no nutrient addition at all, these bottles showed no significant (p>0.05) NAFC degradation post oxidative step. Indicating that phosphorus and nitrogen are critical in NAFC degradation. Recovery of microbial diversity is a key finding to demonstrate that the microbial community can withstand the harsh oxidative stress of UV photocatalytic oxidation and continue to degrade NAFCs present. This experiment confirms that the microbial community benefits NAFC degradation with the addition of nutrients and can survive oxidative stress to continue to degrade OSPW NAFCs.

  • Subjects / Keywords
  • Graduation date
    Fall 2020
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
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