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Oil sands process water (OSPW) contains organics, inorganics, and particles. To understand and improve the ozonation performance, it is crucial to clarify the effect of inorganics and particles on the ozonation of OSPW organic compounds. In this study, OSPW containing only inorganic fraction (OSPW-IF) was obtained after the organics were adsorbed onto granular activated carbon. A model naphthenic acid (NA) compound, cyclohexanecarboxylic acid (CHA), was dissolved in OSPW-IF (CHA-OSPW-IF) and NaHCO3 buffer (CHA-Buffer). Ozonation of CHA-Buffer achieved higher CHA removal and lower utilized ozone dosages compared to CHA-OSPW-IF. Some inorganic ions present in OSPW (i.e., NH4+, HCO3−, and Cl−) caused a slight reduction of CHA degradation. Inorganics in OSPW inhibited the degradation of natural-occurring NAs while a negligible influence of particles on the ozonation of NAs was found. This research suggests that ozonation could be better utilized as an intermediate or post-treatment step in a treatment train for OSPW reclamation. [ABSTRACT FROM AUTHOR]

Naphthenic acids (NAs) are persistent compounds that contribute to the toxicity of oil sands process-affected water (OSPW). In this study, the effects of ozone and ozone/hydrogen peroxide on the NAs degradation in buffered water and OSPW were examined. Cyclohexanoic acid (CHA) was used as a model NAs compound in buffered water experiments at two different pHs, using radical scavengers. At pH 9, the addition of carbonate did not have any effect on CHA degradation. Additions of tert-butyl alcohol and tetranitromethane decreased the CHA degradation levels. For the OSPW experiments, degradation of acid-extractable fraction (AEF) and NAs was examined. Approximately 90% of AEF was oxidized in a semi-batch system. In a batch system, 99% of OSPW NAs were degraded. This study demonstrated that ozone and ozone/hydrogen peroxide could be suitable treatment processes for OSPW remediation. [ABSTRACT FROM AUTHOR]

Oil sands process-affected water (OSPW) is a toxic and poorly biodegradable mixture of sand, silt, heavy metals, and organics. In this study, qualitative and quantitative comparisons of naphthenic acids (NAs) were done using ultraperformance liquid chromatography time-of-flight mass spectrometry (UPLC TOF- MS), Fourier transform ion cyclotron resonance (FT-ICR) MS, and ion mobility spectrometry (IMS). The unique combination of these analyses allowed for the determination and correlation of NAs, oxidized NAs, and heteroatom (sulfur or nitrogen) NAs. Despite its lower resolution, UPLC-TOF MS was shown to offer a comparable level of reliability and precision as the high resolution FT-ICR MS. Additionally, the impacts of ozonation (35 mg/L utilized ozone dose) and subsequent NAs degradation on OSPW toxicity were assessed via a collection of organisms and toxicity end points using Vibrio fischeri (nonspecific), specific fish macrophage antimicrobial responses, and fish olfactory responses. Fish macrophages exposed to ozonated OSPW for 1 week showed higher production of reactive oxygen and nitrogen intermediates; however, after 12 weeks the responses were reduced significantly Fish olfactory tests suggested that OSPW interfered with their perception of odorants. Current results indicate that the quantification of NAs species,using novel analytical methods, can be combined with various toxicity methods to assess the efficiency of OSPW treatment processes. [ABSTRACT FROM AUTHOR]