Methane production and oxidation in oil sands tailings ponds: Controlling factors and effects on fugitive greenhouse gas emissions

据估计，阿尔伯塔省油砂尾矿池每年排放的游离甲烷总量为230万吨二氧化碳当量。加拿大的甲烷排放预算总额为9200万吨二氧化碳当量/年。这意味着，与110平方公里的微小表面积相比，尾矿池产生的总量非常不成比例。不同尾矿库估算的甲烷流出率差异较大，在三个数量级以上。这种差异最终可能是由于不同的管理决策，如使用特定的萃取化学品、添加矿物如石膏作为絮凝剂、水循环管理和池塘年龄，这些都会影响甲烷循环微生物的发展。从最古老的活跃池塘中测量到的甲烷通量最高。这些数据表明，随着池塘年龄的增长，它们可能会产生更多的甲烷，但特定的管理决策可能允许我们通过对现有的甲烷循环微生物群落进行生物工程来限制甲烷的排放。本研究的目的是检测不同油砂尾矿库的甲烷通量，了解控制甲烷产生和甲烷氧化相关微生物过程的因素。具体来说，我们将：1。评价甲醇氧化法去除不同尾矿库甲烷的效果2。确定尾矿库中是否发生厌氧甲烷氧化，确定负责好氧甲烷氧化和厌氧甲烷氧化的微生物3。比较不同油砂尾矿库的甲烷产量和氧化速率，评估潜在影响甲烷生成和甲烷氧化的管理因素4。评估添加氧化还原活性氧化铁矿物作为抑制产甲烷菌和刺激厌氧甲烷氧化菌的策略的有效性加拿大油砂创新联盟将为该研究提供现场样品和实验室分析。研究结果将为尾矿库的管理提供信息，以尽量减少甲烷的排放。

Total annual fugitive methane emissions from oil sands tailings ponds in Alberta are estimated at >2.3 Mt of CO2e. Canada's total methane emission budget is 92 Mt CO2e/yr., meaning that tailings ponds produce a hugely disproportionate amount of this total compared to their tiny surface area of 110 km2. There is a large range in the methane efflux rates estimated from different tailings ponds, over three orders of magnitude. This variability may be ultimately due to different management decisions, such as the use of particular extraction chemicals, addition of minerals like gypsum as flocculants, water recycling management, and pond age, which all affect the development of methane-cycling microorganisms. The highest methane fluxes have been measured from the oldest active ponds. These data suggest that ponds may become more methanogenic as they age, but that particular management decisions may allow us to limit emissions of methane by bioengineering the methane-cycling microbial communities present. The aim of this study is to examine methane fluxes in various oilsands tailings ponds, and understand what factors control the linked microbial processes of methane production and methane oxidation. Specifically we will: 1. Estimate the effectiveness of methanotrophy in removing methane from different tailings ponds 2. Determine whether anaerobic methane oxidation occurs in tailings ponds, and determine the microbes responsible for both aerobic and anaerobic methane oxidation3. Compare methane production and oxidation rates in diverse oil sands tailings ponds and assess management factors that potentially affect methanogenesis and methanotrophy 4. Estimate the effectiveness of adding redox-active iron oxide minerals as a strategy for inhibiting methanogens and stimulating anaerobic methanotrophsThe Canadian Oil Sands Innovation Alliance will provide field samples and laboratory analyses for the research. The results will inform management of tailings ponds to minimize methane emissions.