In Alberta’s Athabasca oil sands region (AOSR), over 1.25 billion m3 of tailings waste from the bitumen extraction process are stored in tailings ponds. Fugitive emissions associated with residual hydrocarbons in tailings ponds pose an environmental concern and include greenhouse gases (GHGs), reduced sulphur compounds (RSCs), and volatile organic compounds (VOCs). Froth treatment tailings (FTT) are a specific type of tailings waste stream from the bitumen froth treatment process that contains bioavailable diluent: either naphtha or paraffins. Tailings ponds that receive FTT are associated with the highest levels of biogenic gas production, as diverse microbial communities biodegrade the residual diluent. In this review, current literature regarding the composition, chemical analysis, and microbial degradation of FTT and its constituents is presented in order to provide a more complete understanding of the complex chemistry and biological processes related to fugitive emissions from tailings ponds receiving FTT. Characterizing the composition and biodegradation of FTT is important from an environmental perspective to better predict emissions from tailings ponds and guide tailings pond management decisions.
The comprehensive chemical characterization of crude oil is important for the evaluation of the transformation and fate of components in the environment. Molecular-level speciation of naphthenic acid fraction compounds (NAFCs) was investigated in a mesoscale spill tank using both negative-ion electrospray ionization (ESI) Orbitrap mass spectrometry (MS) and positive-ion atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry (APPI-FT-ICR-MS). Both ionization techniques are coupled to high-resolution mass spectrometric detectors (ESI: Orbitrap MS; APPI: FT-ICR-MS at 9.4 T), enabling insight into the behavior and fate of petrogenic compounds during a simulated freshwater crude oil spill. Negative-ion ESI Orbitrap-MS reveals that oxygen-containing (Ox) classes are detected early in the spill, whereby species with more oxygen per molecule evolve later in the simulated spill. The O2-containing species gradually decreased in relative abundance, while O3 and O4 species increased in relative abundance throughout the simulated spill, which could correspond to a relative degree of oxygen incorporation. Nonpolar speciation by positive-ion APPI 9.4 T FT-ICR-MS allowed for the identification of water-soluble nonpolar and less polar acidic species. Molecular-level graphical representation of elemental compositions derived from simulated spill water-soluble and oil-soluble species suggest that biological activity is the primary degradation mechanism and that biodegradation was the dominant mechanism based on the negative-ion ESI Orbitrap-MS results.
A method using normal phase high performance liquid chromatography for the analysis of olefins and diolefins in cracked petroleum samples is proposed and validated in this work. A silver-impregnated silica column is used to separate olefin and diolefin species, resulting in accurate quantification of both group-types. Separations are completed using an isocratic hexane mobile phase, with no sample clean up or backflushing required. Results from the analysis of 11 model compounds are shown, as well as quantification data for four representative samples; figures of merit are also described.