Biodegradation of cycloalkanes under different redox conditions

露天开采和热水沥青开采作业存在几个问题；其中最重要的是对大量流动细尾砂的管理。非水溶剂萃取（NAE）工艺有可能减少油砂活动对环境的影响，因为它可以产生高沥青回收率，消除流体细尾矿的生产，减少对淡水消耗的依赖。此外，使用NAE固体与原始土壤混合可以更快地回收矿区。NAE萃取沥青后，大部分溶剂从工艺中回收再利用，但一小部分未回收的溶剂仍与NAE固体共沉积。寻找一种安全、快速地去除NAE中未回收溶剂的方法，将有利于矿区的复垦。生物修复是处理含烃尾矿的一种经济有效的方法。利用土壤微生物群落降解NAE固体中残留溶剂的能力可以减少NAE固体在坑中沉积或在高地或湿地情况下管理对环境的影响。在拟进行的研究中，我们将模拟土壤坑（好氧/厌氧）、高地（好氧）和湿地（厌氧）场地条件，在实验室建立小规模的微观实验，研究环戊烷和环己烷浸渍NAE固体在不同氧化还原条件（好氧、硝酸盐还原、硫酸盐还原和产甲烷）下的生物修复作用。该研究结果将为制定沥青提取过程中产生的NAE固体的管理策略和在回收场地建立可持续的生态系统提供基础科学信息。

Surface mining and hot water bitumen extraction operations have several issues; the significant one is the management of enormous volumes of fluid fine tailings. Non-aqueous solvent extraction (NAE) process has a potential to reduce environmental impact of oil sands activity by yielding high recovery of bitumen, eliminating production of fluid fine tailings and reducing dependence on fresh water consumption. In addition, mine sites might be reclaimed more rapidly using NAE solids mixed with pristine soils. After NAE extraction of bitumen, the majority of the solvent is recovered from the process and re-used, but a small portion of unrecovered solvent remains incorporated and co-deposited with NAE solids. Finding a way to safely and rapidly remove the unrecovered solvent from NAE will benefit mine site reclamation. Bioremediation is a cost-effective method to treat tailings containing hydrocarbons. The ability to use soil microbial communities for the degradation of residual solvent from NAE solids could reduce the environmental impact if NAE solids are deposited in pits or managed under upland or wetland scenario. In the proposed research, we will be simulating soil-pit (aerobic/anaerobic), upland (aerobic) and wetland (anaerobic) site conditions by setting up microcosm experiments at small-scale in the laboratory and investigate bioremediation of NAE solids impregnated with cyclopentane and cyclohexane under different redox conditions (aerobic, nitrate-reducing, sulfate-reducing and methanogenic).The results of the proposed study will provide fundamental scientific information to develop strategies for managing NAE solids produced during bitumen extraction process and establishing a sustainable ecosystem on reclaimed sites.