Surface mining in the Athabasca oil sands region of Northern Alberta, Canada, results in the disturbance of significant areas of boreal forest landscape. The Aurora Soil Capping Study is a reclamation research project that aims to find the optimal soil capping (cover) material and thickness to re-establish a boreal forest ecosystem above a lean oil sands (LOS) disposal area at Syncrude's Aurora North mine. The objectives of this laboratory and field-based study are to (1) characterize the in-situ hydrocarbon composition of the LOS material, (2) determine the effect of temperature on rates of gas flux and the biodegradation potential of petroleum hydrocarbons (PHC) as a result of microbial activity and (3) determine the potential for PHC to leach into the groundwater system. The results of the laboratory-study show that temperature has a significant effect on the rate of PHC degradation as indicated by the linear relationship observed between temperature and CO2 gas flux rates. The respiratory results from the laboratory-based study were consistent and relatively comparable with data from the field study, which indicates that the column study could be useful in estimating in situ PHC degradation.

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Trichloroethylene (TCE) is a major groundwater contaminant and is a cause of serious health concern. Methanotrophic TCE degradation is very promising compared with other treatments. Methanotrophs produce methane monooxygenases (MMOs) which catalyze methane oxidation and cometabolize chlorinated and aromatic compounds. High rate of TCE degradation is attributed to only soluble MMO (sMMO) expressed mainly by type II methanotrophs under copper-deficient conditions. To make methanotrophic TCE degradation practical, high density methanotrophic biomass with high sMMO activity is required. Methane is the primary substrate for methanotrophs and sufficient quantities must be supplied to support biomass growth. Because of the poor water solubility of methane, mass transfer limitation essentially restricts high biomass production. When methanol was used as the growth substrate, biomass concentration of 7.4 g l-1 Methylosinus trichosporium OB3b was achieved in a 160-h fermentation using an exponential feeding strategy based on pre-determined . Even higher biomass density of 19 and 29 g l-1 biomass were obtained by a modified feeding strategy based on carbon dioxide production. It is concluded that methanol is a promising substrate for the production of large amounts of M. trichosporium OB3bbiomass. In addition, allylthiourea was applied to methanotrophs growth medium to circumvent the inhibitory effect of copper, which inhibits sMMO activity but not particulate MMO (pMMO). We successfully retained sMMO activity by supplementing allylthiourea. Even when M. trichosporium OB3b was grown with 4.5 M copper, which would completely block sMMO expression, addition of 15 M allylthiourea preserved half of the sMMO activity. It was also observed that switching the growth substrate from methane to methanol did not significantly affect sMMO activity. An immobilized soil bioreactor was developed to examine the efficiency of methanotrophic TCE degradation by combining the knowledge obtained on high biomass production and applying allylthiourea for sMMO expression. In a batch TCE degradation experiment, about 63% of TCE was removed in 5.75 h. The maximal TCE degradation rate of 1.40 mg l-1 h-1 was obtained in a continuous TCE degradation at a dilution rate of 0.15 h-1. This study demonstrated the effectiveness of a novel bioreactor system for methanotrophic TCE degradation. / Thesis (Ph.D, Chemical Engineering) -- Queen's University, 2008-09-30 14:51:26.59

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Extraction of bitumen from oil sands by surface mining and alkaline hot water process has generated large amount of oil sand process water (OSPW) which are contaminated by naphthenic acids (NAs). Due to the toxic and harmful nature of NAs, OSPW have been stored on-site in extremely large tailing ponds. With the understanding that the OSPW must be treated before their release into the natural water bodies and the need for reuse of the water, there is an urgent need in finding ways to treat these OSPWs effectively and economically. Numerous works on different treatment methods including photocatalysis, ozonation, adsorption, phytoremediation, simulated wetlands and bioremediation have been conducted and bioremediation has been proved as one of the most feasible ways among these methods. Research works on biodegradation of NAs, both aerobically and anoxically, have been conducted intensively in our research group in the past several years. Using surrogate NAs, specially trans-4-methyl-1-cyclohexane carboxylic acid (trans-4MCHCA), aerobic (Paslawski et al., 2009a,b,c, Huang et al., 2012; D’Souza et al., 2013) and anoxic (Gunawan et al., 2014) biodegradations of NA have been studied in batch, CSTR, biofilm system and circulating packed-bed bioreactor. Effects of naphthenic acid concentration, temperature, and naphthenic acid loading rate on the biodegradation process have been investigated. The results of the anoxic biodegradation of trans-4MCHCA in the presence of nitrate as an electron acceptor revealed that its performance was similar or better than the aerobic biodegradation. The results of that study also indicated the production of nitrite during the denitrification of nitrate and its subsequent consumption as part of biodegradation process. Given the importance of denitritation (nitrite reduction) as an essential step in anoxic biodegradation in the presence of nitrate, and the potential inhibitory effect of nitrite, the current research was conducted with the aim of investigating the performance of the anoxic biodegradation of trans-4MCHCA in the presence of nitrite as an electron acceptor, using batch, CSTR and biofilm reactors. The results of batch studies showed that nitrite at concentration up to 690 mg L-1 did not have a marked inhibitory effect but concentrations above 920 mg L-1 imposed a strong inhibitory effect. The optimum temperature was found to be in the range 24 C to 30°C. Continuous anoxic biodegradation of trans-4MCHCA with nitrite in CSTR achieved the maximum trans-4MCHCA biodegradation rate of 14.4 mg L-1 h-1 at a trans-4MCHCA loading rate of 22.9 mg L-1 h-1, which was about seven fold lower than the maximum trans-4MCHCA biodegradation rate observed with nitrate as an electron acceptor (105.4 mg L-1 h-1; Gunawan 2013). Both the trans-4MCHCA and nitrite degradation rates decreased with further increase of trans-4MCHCA loading rate. Using the experimental data the biokinetic coefficients Y (biomass yield), Ke (endogenous rate constant), μm (maximum specific growth rate) and Ks (saturation constant) were determined as 0.3 mg cell mg substrate-1, ~0 h-1, 0.4 h-1 and 20.9 mg substrate L-1, respectively. Similar pattern was observed in the biofilm system whereby the maximum trans-4MCHCA biodegradation rate was 82.2 mg L-1 h-1 at a trans-4MCHCA loading rate of 171.8 mg L-1 h-1, was about five folder lower than the maximum trans-4MCHCA biodegradation rate observed when nitrate was used as an electron acceptor (435.8 mg L-1 h-1; Gunawan 2013). The findings of current study suggested that the anoxic NA biodegradation in the presence of nitrite occurred at rates which were lower than those observed in the presence of nitrate, as well as those obtained under aerobic conditions with oxygen as the electron acceptor.

There is no abstract available for this thesis. / Department of Natural Resources and Environmental Management

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Bioaugmentation with Dehalococcoides-containing cultures is a successful technology for the remediation of chlorinated ethene-contaminated roundwater. The overall goal of this research was to identify and characterize genes that are used by a Dehalococcoides-containing culture, KB-1, during degradation of Trichloroethene (TCE) to ethene, via cis-Dichloroethene (cDCE) and vinyl chloride. Firstly, the diversity and dynamics of the microbial populations within KB1 was assessed using 16S rRNA clone libraries and quantitative PCR analyses. Secondly, reductive-dehalogenase-homologous- (RDH) genes in KB1 were identified, sequenced and their transcription compared through RNA-generated RDH cDNA clone libraries. Finally, to elucidate functionally important genes within the community, Shotgun metagenome microarrays were constructed and used to investigate transcription during dechlorination. Results of the phylogenetic analyses indicated that KB1 is a diverse community of microorganisms whose stability is enhanced by functional redundancy within the culture. To fully understand this diverse community of uncultivated microorganisms a metatranscriptome approach was used. Experiments with shotgun metagenome microarrays identified spots which were statistically significantly differentially expressed during dechlorination. These spots were then sequenced, revealing Dehalococcoides and non-Dehalococcoides-genes which are important during dechlorination. These results demonstrated that shotgun microarrays can be constructed without prior sequence knowledge and used to effectively examine differential transcription within an uncultivated community. Subsequently, all of the spots of the array were sequenced, and additional array experiments were conducted. Sequencing identified 24 reductive dehalogenase genes in the culture, and analysis of the microarray results indicated that many of these RDH genes were differentially expressed in response to certain chlorinated compounds. Interspecies interactions were also highlighted as results suggested that non- Dehalococcoides microorganisms provide partial corrinoids which Dehalococcoides salvages to synthesize cobalamin which is essential for reductive dehalogenation. Transcription of CRISPR-associated genes also indicated interaction between phage and other microorganism in the KB1 community. Overall these results provided sequence and transcription information about possible biomarkers for reductive dechlorination by KB1 and can be used for more effective design and monitoring of bioremediation technologies.