Enhancing the Treatment of Oil Sands Process Water through Bioremediation

加拿大阿尔伯塔省的油砂行业目前每天生产100多万桶石油，而该地区估计有1740亿桶沥青储量。这些沥青沉积物不易获得，必须使用大量热水提取。这反过来又导致了大量的油砂形式的废物，受工艺影响的水和尾矿。阿尔伯塔省政府制定了一项零排放政策，要求这些材料在现场回收或储存，并要求运营商随着时间的推移将受影响的场地恢复到以前的自我维持生态系统。现场储存和处理的一种选择是尾坑湖，它由覆盖着一层水的流动细尾矿组成。据估计，池塘中存在的污染物将随时间自然衰减。然而，作为一种成功的复垦选择，坑底湖的使用尚未在整个现场规模上得到证明，而且对化学物质从沉积物到上覆封顶水的通量以及微生物介导的生物地球化学反应的影响的关注仍然存在。目前存在臭氧化等化学补救方案，但成本太高，无法大规模使用。我们实验室最近的工作表明，在油砂过程中受影响的水中加入一种提取过程废物（石油焦），有望成为一种廉价的有效吸附污染物的方法。然而，众所周知，石油焦在与油砂工艺影响的水接触时，会滤出无机化合物（如钒），这将需要后续处理。处理油砂废弃物的一种低成本补救方案是利用能够降解适当污染物的微生物。这项发现计划的主要目标是：1)研究坑底湖中发生的生物地球化学反应；2)识别能够降解污染物的微生物联合体或个体生物，并在将油砂过程影响的水围入底坑湖泊之前或期间加强对其的修复。本研究的短期成果将包括：1)增加对尾坑湖内污染物通量和生物地球化学的了解；2)评估本地微生物群落和分离生物降解关注污染物的能力；3)评价了采用石油焦联合钒生物修复技术对尾坑湖围封前油砂工艺影响水进行有效处理的可行性。从长远来看，这项研究将提高我们对自然生物修复过程的认识，并为我们监测和提高填海活动的有效性和时间表提供工具。

The oil sands industry in Alberta, Canada, currently produces over 1 million barrels of oil per day, drawing from the estimated 174 billion barrels of bitumen reserves in the area. These bitumen deposits are not readily available and must be extracted using large volumes of hot water. This in turn leads to large volumes of waste in the form of oil sands process-affected water and tailings. The Government of Alberta has instated a zero-discharge policy that requires these materials be recycled or stored on site and mandates that over time operators reclaim impacted sites back to their former self-sustaining ecosystems. One on-site storage and treatment option is end-pit lakes, which consist of fluid fine tailings capped with a layer of water. It is projected that the pollutants present in the pond will undergo natural attenuation over time. However, the use of end-pit lakes as a successful reclamation option has not yet been demonstrated at full field scale, and concerns regarding the flux of chemicals from sediments to overlying cap water and the effects of microbially mediated biogeochemical reactions remain. Chemical remediation options such as ozonation exist, but are too costly for large-scale use. Recent work in our lab has demonstrated that the addition of an extraction process waste product (petroleum coke) to oil sands process-affected water shows promise as an inexpensive way to effectively adsorb contaminants. However, petroleum coke is known to leach inorganic compounds (such as vanadium) upon contact with oil sands process-affected water, which would require subsequent treatment. One low-cost remediation option to treat oil sands waste is to utilize microorganisms that are able to degrade the appropriate contaminants. The primary objective of this Discovery Program is to 1) investigate the biogeochemical reactions occurring in end-pit lakes; and 2) identify a microbial consortium or individual organism(s) able to degrade contaminants and enhance the remediation of oil sands process-affected water prior to, or during, its enclosure in end-pit lakes. The short-term outcomes of this research will include 1) an increased understanding of contaminant flux and biogeochemistry within the end-pit lakes; 2) an assessment of the ability of the indigenous microbial community and isolated organisms to degrade contaminants of concern; and 3) an evaluation of the feasibility of using petroleum coke coupled with the bioremediation of vanadium to effectively treat oil sands process-affected water prior to enclosure in end-pit lakes. Long term, this research will enhance our knowledge of the natural bioremediation process and provide us with the tools to monitor and enhance both the effectiveness and the timeline of reclamation activities.