Technological advances are required to reduce the environmental impact of the Canadian oil sands. Oxy-direct contact steam generation (DCSG) is one such way to move toward this goal, by producing steam for oil sands operations with a higher efficiency, lower fresh water consumption, and lower CO₂ emissions than traditional once-through steam generators. For DCSG, untreated process water, which may contain a variety of inorganics, is injected directly into the combustor to produce steam. The inorganic material that may deposit in the combustor as a result of that process water was studied for two applications of DCSG in the Canadian oil sands: (1) steam assisted gravity drainage (SAGD), and (2) mining, in order to inform refractory material selection for the combustor. For SAGD, free water knockout tank discharge was used as the process water and resulting deposits in the combustor were predicted to be high in silica and sodium oxide, and enriched with sodium sulfate as the potential operating temperature of the combustor was lowered. At the lowest combustor temperature studied (1075 °C), a low viscosity molten salt phase rich in sodium sulfate was also expected to form. It is recommended that the operating temperature of the combustor be as low as possible while still remaining above the formation temperature of this potentially corrosive salt phase, thus in the range of 1200-1250 °C in the regions of the wall where solids are expected to impact it. A number of candidate refractory materials were assessed through corrosion models and corrosion tests. Aluminosilicate based refractory materials should be avoided due to their potential reaction with the sodium oxide in the slag. This can result in formation of low density solid phases such as nepheline, which can damage the refractory material through volume expansion. Of the three refractories tested, mullite zirconia yielded the worst corrosion resistance, with dissolution of the binder phase and full penetration by sodium oxide. Chromia corundum yielded the greatest resistance to penetration of the materials tested, though some dissolution of the chromia in the slag was still evident. Further investigation into high chrome refractory materials is recommended for this application. For mining applications, mature fine tailings water (MFT) combined with an oil sands processing water (OPW) was used as the process water for injection. Due to the high liquidus of the resulting inorganic deposits, co-injection of a fluxant is recommended to reduce the liquidus and viscosity of the resulting slag solution, thereby maximizing the combustor efficiency by reducing the required operating temperature. Dolomite was identified as the optimal fluxant, at a concentration of 20 wt % CaMgO₂ in the fluxed slag. This mixture was found to have a viscosity of just under 25 Pa·s at 1300 °C, making this a good operating point for the DCSG combustor, as the slag should flow freely and not cause plugging. The corrosion resistance of several candidate refractory materials was assessed through modelling and laboratory scale testing for both the fluxed and non-fluxed slag. Similar to the results for SAGD, of the refractories tested, chromia corundum offered the greatest resistance to penetration, while mullite zirconia was most deeply penetrated by sodium oxide. Again, a chromia-containing refractory is recommended for further investigation for use in the DCSG combustor. Other candidate refractories investigated in the models that warrant testing are chromia spinel and magnesium aluminate spinel. For future work, further corrosion tests at multiple durations are recommended, as well as characterization of refractory samples from CanmetENERGY’s DCSG pilot plant and quantification of the effects of slag exposure on the mechanical strength of the refractory materials.

Wetland reclamation efforts in the Athabasca Oil Sands Region seek to restore important ecosystem services that were lost consequent of disturbance from oil sands mining development in northern Alberta, Canada. Constructed on the Syncrude Canada Ltd. mineral surface lease, the Sandhill Watershed is the first attempt to engineer a landscape capable of supporting a self-sustaining wetland above a backfilled open-pit mine. In the chapters below, through characterization of porewater chemistry patterns, plant community structure, physical characteristics of soil and nutrient availability the overall performance of the wetland area (the Sandhill Wetland) is evaluated. Further, observations at the reclaimed site are compared to 12 reference wetlands (10 fens and 2 marshes) to evaluate the type of wetland to which the Sandhill Wetland is most analogous. After six growing seasons, although water table position management has occurred annually, the Sandhill Wetland exhibits many attributes similar to those of the natural sites monitored. In terms of porewater chemistry, the dominant anions and cations present in near-surface water (bicarbonate, sulfate, chloride, sodium, calcium, and magnesium) have increased annually since the first growing season. If trends continue, the chemical conditions at the reclamation site could be analogous to saline fens in about 7-8 years based on projections for increasing sodium and chloride concentrations. The Sandhill Wetland currently exhibits porewater chemistry attributes most similar to saline fens and slightly brackish marshes. Total plant cover across the reclaimed wetland was quite high averaging 95% in the sixth growing season. Using multivariate approaches (NMDS), results show that plant community structure across high and intermediate water table position areas are most comparable to marshes, with Typha latifolia and Carex aquatilis exhibiting the highest cover. Across the periphery of the site, where water table position is several centimeters below the soil surface, plant communities are quite dissimilar from the reference sites and dominated by the grass Calamagrostis canadensis. While sodium-tolerant species are present at the site, albeit at low abundance, it is unclear whether long-term exposure to sodium-dominated porewaters currently present at the Sandhill Wetland will affect performance of wetland plants that established under low-sodium conditions. In terms of soil characteristics, clear differences were apparent, namely, for soil bulk density patterns. Bulk density observations across all areas at the Sandhill Wetland were higher than the reference sites and total soil carbon concentrations were also low. These observations were expected, and as the Sandhill Wetland matures, I predict annual production and (or) deposition of plant litter/ roots and increased biological activity will restore near-surface soil properties in the wetland area, thereby increasing TC concentrations and reducing soil compaction. For functional processes, using plant root simulator (PRS) probe ion exchange membranes, results demonstrate nutrient supply across the Sandhill Wetland was most similar to the moderate-rich and saline fens except for sulfur supply, which was considerably elevated. Based on PRS probe and porewater observations, the Sandhill Wetland is not a eutrophic system in the sixth growing season, and supply for most nutrients are within the ranges of natural systems. However, effects from local atmospheric nitrogen deposition (reported up to 12 kg N ha-1 yr-1) could alter structure and function over subsequent growing seasons. Currently, ecosystem health and functionality of the belowground environment appears to be adequately restored at the reclamation site. Lastly, as no officially recognized protocols exist for evaluating performance of recently reclaimed wetlands constructed above open-pit mines, using the Sandhill Wetland as a test site I propose a framework for evaluating reclamation site performance. Although the proposed evaluation protocol does not rely on multivariate techniques, the performance evaluation results support the previous findings (that were based on multivariate analysis) that a marsh-like analogue is the most realistic reclamation outcome for the reclaimed Sandhill Wetland. While the reclamation has been highly successful in terms of creating a wetland that has persisted, future monitoring of water chemistry and plant community structure should continue at the Sandhill Wetland, to capture important successional changes that may occur as the site matures.

Peatlands comprise of approximately half of the Athabasca oil sands region, many of which overlay some of the world’s largest bitumen deposits where surface mining for this resource has permanently altered the landscape. By law, companies must reclaim disturbed landscapes into functioning ecosystems including integrated upland-wetland systems with the objective of forming sustainable peat-forming wetlands. This thesis presents six years (2013 – 2018) of water balance and associated salinity data from one of the two existing constructed upland-wetland systems, the Sandhill Fen Watershed (SFW), a 52-ha upland-wetland built on soft tailings to evaluate the hydrological and hydrochemical performance and its potential to be self-sustaining. Following a considerable decrease in hydrological management, the dominant water balance components changed from primarily horizontal (inflow and outflow) to vertical fluxes (precipitation and evapotranspiration) which increased inundation, encouraged salt accumulation and changed plant communities. Results suggest that current conditions are not favourable for fen-peatland development as marsh-like conditions have developed, limiting water conserving functions and the ability to persist long-term in a changing climate. In terms of winter processes, topography currently controls snow accumulation, redistribution and melt at SFW while the role of vegetation in these processes is expected to increase as it continues to develop. Runoff ratios of snowmelt from hillslopes were drastically different than those previously reported for reclaimed peatland watersheds highlighting the influence of different soil materials used during construction. Under various climate change scenarios of a warmer and wetter climate, results from the Cold Regions Hydrological Model indicate that the influence of winter processes will decrease, potentially putting reclaimed systems at greater risk of moisture stress. Substantial hydrochemical changes have occurred as salinity was relatively low at the study onset as high volumes of inflow and outflow prevented ion accumulation. Over time, salinity continued to increase year-over-year throughout SFW from 2013 to 2018 in the wetland and margin areas. This increase in site-wide salinity was attributed to the shift in dominant water balance fluxes, changes in water table position and increased mixing of SFW waters with deeper saline groundwater that underlies the system. Based on its current conditions, it is unlikely that SFW will support peat-forming vegetation. It is recommended that design strategies shift to incorporate characteristics found in undisturbed saline peatlands that are capable of supporting peat-forming vegetation in a saline environment. / Thesis / Doctor of Philosophy (PhD) / A better understanding of the hydrological functioning of reconstructed peatlands in the Athabasca oil sands region is required as it is a novel approach in this region and there is potential for thousands of hectares of land that will require this reclamation in the future. Due to their recent establishment potential trajectories of constructed peatlands have yet to be fully analyzed as only recently has sufficient data been collected to evaluate the hydrological and hydrochemical functioning and provide insight on its overall success. While design strategies may seem sound, these constructed systems are completely human-made and it is unclear how they will develop and function in a highly disturbed landscape. Thesis results suggest that current conditions are not favourable to sustain a peatland as marsh-like conditions have developed which will limit its ability to persist long-term in a dry and changing climate. It is recommended that design strategies shift to incorporate characteristics found in undisturbed saline peatlands that are capable of supporting peat-forming vegetation in a saline environment. Due to the many challenges associated with reclamation in this region, lessons learned from this pilot project will help guide future peatland construction.

As oil production increases in Alberta’s Athabasca Oil Sands Region (AOSR), optimization of tailings management processes will be integral to the successful reclamation of tailings-based environments. Syncrude Canada Ltd. has established an innovative dry-storage method for their wastes known as composite tailings (CT) that supports mine closure objectives by providing a base for terrestrial reclamation landscapes. Syncrude’s Sandhill Reclamation Fen is the first instrumented research wetland of its kind to be developed in the AOSR and it overlays a sand-capped composite tailings deposit in a retired open-pit mine site. This stratified sulfur-rich environment is highly anthropogenically altered and consists of three distinct zones: a constructed wetland, a 10m layer of sand, and 40m of CT. As oil sands tailings systems are becoming globally significant sulfur reservoirs due to their size, sulfur content, and diverse microbial communities, understanding the mechanisms behind H2S generation in novel tailings structures will help inform our understanding of sulfur-rich environments. This study is the first to characterize the sulfur biogeochemistry in each zone of the Sandhill Reclamation Fen deposit in an effort to establish the potential for microbial sulfur cycling and explore the mechanisms controlling H2S generation. Porewater ΣH2S(aq) was detected at all depths, increasing with depth from the surface of the wetland (<1.1 μM) and peaking in the sand cap (549 μM). Across all sampling trips, ΣH2S(aq) concentrations were consistently highest in the sand cap, with sampling-associated H2S gas concentrations in the wells reaching 104-180 ppm. Abundance of dissolved sulfate (0.14-6.97 mM) did not correlate to the distribution of ΣH2S, and dissolved organic carbon (21.47-127.72 mg/L) only positively correlated with the observed maxima of ΣH2S in the sand-cap. Identical sodium and chloride distributions in the sand and CT supported the model of upward migration of CT-derived porewater and fines into the sand cap. Functional metabolic enrichments established the ability of endemic microbial communities from all depths of the deposit to oxidize and reduce sulfur. Experimental microcosms demonstrated 1) the dependence of ΣH2S generation on the presence of fine particles; 2) stimulation of endemic microbial sulfur reduction through amendment with labile carbon and 3) increased generation of ΣH2S in the presence of thiosulfate over sulfate. Field and experimental results indicated that the bioaccessibility of recalcitrant organic carbon in the deposit likely controls rates of ΣH2S generation at depth. While the mechanisms relating CT-derived fines to ΣH2S in the sand cap are still unconstrained, the sand layer is clearly a bioreactive mixing-zone supporting optimal conditions for ΣH2S accumulation. These findings inform our understanding of biogeochemical sulfur cycling in novel oil sands reclamation deposits and will advise on-going optimization of tailings-based landscape management practices. / Thesis / Master of Science (MSc)

In this study, phospholipid fatty acids (PLFA) and carbon isotopes were used to characterize the response of in situ microbial communities to a pilot-scale wetland reclamation project in the Alberta oil sands, and to investigate their role in carbon cycling at the reclamation site. The Sandhill Fen reclamation project in the Athabasca oil sands region (Fort McMurray, Alberta, Canada) has created an artificial freshwater fen typical of the boreal forest region in which the oil sands occur. At this site, composite tailings (CT) residue was overlain with a thick sand cap and a freshwater fen constructed on top. Biomass in the peat material of the fen was comparable to that found in natural fens, and a comparison of PLFA profiles in peat, CT from a nearby site, and undisturbed wetlands in the area showed that microbial communities in Sandhill fen were more similar to those in the CT than those in undisturbed wetlands. Bacteria dominated the biomass, including a small percentage of sulphate reducing bacteria that are of particular interest in the reclamation project. Fungi and other eukaryotes were also present. Analyses of radiocarbon in total organic carbon (TOC) and residue from solvent extraction suggest that there was petroleum present in the peat layer of the fen. A small amount of young carbon from the fen surface has been transported into the CT layer in the form of dissolved organic carbon. Radiocarbon also showed that microbes preferentially metabolized more modern carbon within the carbon sources available to them. Biomass was more related to the age of carbon in the samples than to the TOC concentration, with younger carbon in the peat associated with higher PLFA concentration. / Thesis / Master of Science (MSc)

The processing of bitumen in the Athabasca oil sands region (AOSR) produces extensive volumes of oil sands process-affected water (OSPW) and tailings, which are stored within tailings ponds and settling basins to promote the consolidation of solids and the recycling of water. Oil sands operators are actively investigating dry and wet reclamation strategies in order to reduce their inventory of tailings and return disturbed land back to its original state. An important component of the reclamation of tailings is understanding the environmental fate of naphthenic acids (NAs), which are considered the most toxic constituents of OSPW and tailings. However, since NAs exist as a complex mixture comprised of thousands of compounds from dozens of chemical classes, the characterization of NAs within environmental samples poses significant challenges to analytical chemists. This dissertation is focused on the characterization of naphthenic acids by comprehensive two-dimensional gas chromatography coupled to mass spectrometry (GC×GC/MS). GC×GC/MS offers unparalleled chromatographic separation and peak capacity and has been used in recent years to resolve individual constituents within complex mixtures, including structural isomers. Since the biodegradation and toxicity of NAs is structure-specific and can vary between structural isomers, the profiling of individual NAs by GC×GC/MS is expected to enhance the monitoring of NAs within environmental samples impacted by oil sands activity. In this thesis, GC×GC coupled with time-of-flight mass spectrometry (TOFMS) was used to structurally elucidate a number of ‘unknown’ classical and sulfur-containing naphthenic acids by interpretation of their electron ionization (EI) mass spectra and, if available, confirmed by comparison with the spectra of references standards. GC×GC/TOFMS was also utilized as a fingerprinting tool to assess the temporal and spatial variability at two reclamation sites in the AOSR: Syncrude’s Sandhill Fen reclamation site and Base Mine Lake. Lastly, a methodology was developed which coupled GC×GC with a high resolution quadrupole time-of-flight mass spectrometer (QTOFMS) for the improved profiling of NAs. GC×GC/QTOFMS is advantageous for the monitoring of NAs since it can provide useful fingerprints via isomer distributions, differentiate NAs from several chemical classes, and provide a global overview of the elemental compositions (assigned by mass accuracy) within NA mixtures. / Thesis / Doctor of Philosophy (PhD)

One of the most pressing and polarizing issues in Western Canada today, and for many First Nations groups in particular, is the oil sands of Alberta. My thesis is entitled Energy Uncertainty: The Effects of Oil on the Woodland Cree First Nation. My research is focused on understanding how long-term energy extraction affects the past, present, and futures of the members the Woodland Cree First Nation (WCFN) who are demanding an active role in the planning and consultation processes that affect their lives and their traditional lands. I have found that the energy consultation process is not working for the interests of the WCFN and the effects of oil extraction in this community are examples of how and why it is not working. During the summer of 2013 I spent nine weeks in the WCFN community and used three methods of research: participant observation, interviews, and literature analysis. I completed 22 interviews during my field work research, and made use of nine transcribed interviews with WCFN elders collected in 1995 by Rhonda Laboucan. I used a grounded approach to the content and thematic analysis of my interview and field note data. My thesis is guided by a political ecological approach because this framework challenged me to look at this subject from many angles and perspectives. This approach has kept my research from being narrowly focused on abstracted or stereotypical aspects of the energy extraction process which I cannot understand without attention to its social, political, environmental, and spatial aspects. The body of my thesis includes three chapters which explore: • The practical realities of energy consultation and its relation to Treaty Eight and Traditional Knowledge. • The complex relationship between temporality, fatalism, and the effects of the oil industry on the people, land, and animals of the WCFN. • A detailed ethnographic description of the events and processes that followed a contaminated water spill on the WCFN traditional land. My key findings include: consultation is not working for the interests of the WCFN; oil is impacting the animals, environment, and WCFN community; oil-related spills are affecting (but not being dealt with in a way that respects) WCFN people or land; and there are problems with collection, interpretation, dissemination, and even access to energy extraction and consultation information. My research helps to fill the gaps in our understanding of the complex effects of long-term energy extraction on small communities, in particular the impacts of oil and oil sands development in a small First Nations community context.

Extraction of bitumen from Alberta oil sands produces 2 to 4 barrels of aqueous tailings per barrel of crude oil. Oil sands process water (OSPW) contains naphthenic acids (NAs), a complex mixture of carboxylic acids of the form CnH2n+ZOx that are persistent and toxic to aquatic organisms. Previous studies have demonstrated that aerobic biodegradation reduces NA concentrations and OSPW toxicity; however, treatment times are long. The objective of this study was to evaluate the feasibility of an immobilized soil bioreactor (ISBR) for treatment of NAs in OSPW and to determine the role of ammonium and ammonium oxidizing bacteria (AOB) in NA removal. ISBRs have been used to successfully remediate water contaminated with pollutants such as pentachlorophenol and petroleum hydrocarbons. A system of two ISBRs was operated continuously for over 2 years with OSPW as the sole source of carbon. Removal levels of 30-40% were consistently achieved at a residence time of 7 days, a significant improvement compared to half-lives of 44 to 240 days reported in the literature. However, similar to biodegradation experiments in the literature, a significant portion (~60%) of the NAs was not degraded. The role of AOB in NA removal was investigated by decreasing ammonium concentration and inhibiting AOB activity with allylthiourea, neither of which significantly affected removal, indicating that AOB did not enhance NA removal. Furthermore, high AOB populations actually inhibited the removal of a simple NA surrogate. Therefore, a moderate ammonium concentration of 0.3 g/L is recommended. NA degradation occurred with nitrate as the sole nitrogen source, however, removal levels were lower than those achieved with ammonium. Exploratory studies involving ozonation or biostimulation were conducted with the aim of increasing NA removal. Ozonation decreased NA concentration by 94% and total organic carbon (TOC) by 6%. Subsequent ISBR treatment removed ~30% of the remaining TOC. Addition of a NA surrogate increased heterotrophic NA-degrading populations due to the increase in available carbon, resulting in a significant increase in NA removal levels. However, use of a surrogate may result in a population that is only adapted to degradation of the NA surrogate. / Thesis (Master, Chemical Engineering) -- Queen's University, 2013-06-20 14:53:47.498

This research is an experimental, field and numerical study of the sedimentation and consolidation of in-line thickened oil sands fine tailings. In-line thickening is a process that adds flocculant and coagulant into a modified tailings pipeline in a multi stage fashion to improve the dewatering behaviour of oil sands fine tailings cyclone overflow. The parent untreated cyclone overflow, in-line thickened tailings and sheared in-line thickened tailings were investigated in the laboratory. In-line thickened tailings were produced in the laboratory using the same process as in the field project and sheared in-line thickened tailings were prepared by shearing the thickened tailings with a specified shearing effort to simulate tailings transportation. A combination of hindered sedimentation tests, compressibility standpipe tests and large strain consolidation tests with vane shear tests was then used to capture a full range of sedimentation, consolidation and shear strength characteristics for these materials. Results show that the in-line thickening process significantly improves hydraulic conductivity and undrained shear strength of the fine tails. Shearing damages some of the floc structure but does not cause the material to fully return to the original state of the cyclone overflow. The laboratory data of the in-line thickened tailings was compared with field performance at two in-line thickened tailings pilot scale ponds and with a validation standpipe test by utilizing a developed finite strain consolidation model. Good agreements were obtained between the field performance, the laboratory test results and the validation standpipe test. These good agreements confirmed the validity of the laboratory determined geotechnical parameters and of the developed numerical model and indicated that it is possible to model large scale field performance with small scale laboratory tests. Finally, composite tailings was made from the in-line thickened tailings and was found to have a similar segregation boundary to that of gypsum treated composite tailings made with mature fine tailings but had a much higher hydraulic conductivity and shear strength which were inherited from the flocculated fines. / Geotechnical Engineering

Oil sands operators are being faced with the challenge of reclaiming the large volumes of slurry tailings created during oil sands processing. New regulations mandate that operators must minimize fluid tailings by capturing fines in dedicated disposal areas, leading to a ‘trafficable’ or solid deposit. Adding a polyacrylamide polymer to the tailings and thinly spreading them over a sloped disposal area (a process developed by Shell Canada Energy known as the atmospheric fines drying or AFD process) has been shown to enhance the dewatering of tailings which leads to a dry deposit at a much faster rate than traditional methods. Hydroponic experiments using the emergent aquatic macrophytes cattail (Typha latifolia L.) and common reed (Phragmites australis (Cav.) Trin. ex Steud.) were conducted to investigate the phytotoxicity of waters formed during AFD processing. The phytotoxicity of AFD release waters was compared to the phytotoxicity of traditional mature fine tailings (MFT) reclaim water through the monitoring of plant water uptake and whole plant fresh weight over the course of the experiment. It was found that there are no significant differences between the phytotoxicity observed in the MFT and AFD treatments and it was also found that spring runoff melt water from the AFD deposits is less phytotoxic than the original release water. Two additional hydroponic studies using cattail and common reed were also conducted. The first examined the phytotoxic effects attributable solely to the naphthenic acids isolated from Shell’s Muskeg River Mine tailings, and the second evaluated the phytotoxic effects of amending mature fine tailings with gypsum. It was found that the gypsum amended tailings caused greater phytotoxicity in cattail and common reed than tailings without gypsum added. Furthermore, both species were tolerant to growing in nutrient media spiked with naphthenic acids (40 mg/L). The phytotoxicity experiments conducted also demonstrated that common reed is consistently more tolerant to growing in water associated with oil sands tailings and is therefore the more appropriate choice for use in reclamation strategies involving wetland plants. Mass spectrometry was used to determine the naphthenic acid molecular profiles for Shell oil sands tailings. Using low resolution mass spectrometry, no detectable features or changes to the composition of naphthenic acids attributable to Shell processing were found. High-resolution mass spectrometry provided insight into possible plant mediated changes and biodegradation of naphthenic acids. It appears as though, to some extent, cattail is able to dissipate naphthenic acids, which could explain the susceptibility of cattail to the phytotoxic effects of naphthenic acids. Further research is required to determine whether the changes observed in the naphthenic acid mixture are due to microbial degradation and/or a phytotoxic response of the plants studied.