Initial investigations of the potential bacteriological and associated biochemical activity in oil sands mined in Northern Alberta

Abstract Oil sand samples from the Suncor mining operations in Northern Alberta were investigated for active microbiological content. Using the technologies associated with bacterial community activities, it was found that the bulk of the activity was related to anaerobic bacteria functioning under fermentative reductive conditions. In 2013, oil sand samples were evaluated to develop protocols and in 2014 these protocols were applied to high grade, low grade, and oxidized ore samples. Five protocols were developed applicable to the oil sands. These included metabolic activity (using ATP), bacterial activity (using Bart testers), community identification (using RASI-MIDI), application of the penetrant CBD (to disperse colloidal biomass), and the generation of bioelectricity by the intrinsic biomass. For ATP activity it was found that all of the oil sand samples tested had some activity. However the low grade ores were found to be as active as in wastewater treatment lagoons. Oxidized ores were found on average to be active at one third the low-grade ores while the high-grade ores were lower on average by 38 times than the low grade ore. This would indicate that the high-grade ore had very little bacterial activity and possibly these ores were now matured. While activity did vary with the type of ore sample, the bacterial population remained relatively constant and was dominated by slime forming, heterotrophic and denitrifying bacteria. Some differences were noted in the relationships between the three groups due to sample sizes being too small to ensure continuity. Community identification found that the protocol yielded a constant type expressed as ENG 610 with very good similarity indexes. Bitumen within the oil sand became mobilized using the dispersant CBD relatively in all grades of oil sand. Bioelectrical potentials were also investigated and it was found that voltages remained fairly constant (e.g. 1.6 volts DC) but did vary in milli-amperages depending on the sample type. In summary, all of the oil sand samples appeared to have detectable activities mostly associated with bacteria. Using the E-tATP activity measurement, it was found that the low grade ores were the most active. However, bacterial communities of SLYM (sliming forming), HAB (heterotrophic aerobic bacteria), and DN (denitrifying bacteria) dominated with the fatty acid fingerprint relating to SCE 610. All oil sand samples were found to be ATP active and contained large populations of the three bacterial communities which shifted from a dormant to an active state depending upon conditions within the ore.