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

油砂尾矿库中甲烷的产生和氧化：控制因素及其对逸散性温室气体排放的影响

• 批准号: 577100-2022
• 负责人: Dunfield, PeterPF
• 金额: $ 35.71万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Alliance Grants
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=744545
• 关键词: Methane; production; oxidation; oil; sands

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.

艾伯塔省油砂尾矿池的年度逃逸甲烷排放总量估计超过 2.3 公吨二氧化碳当量。加拿大的甲烷排放总量预算为 92 公吨二氧化碳当量/年，这意味着尾矿池产生的甲烷排放量与其 110 平方公里的微小表面积相比，远远不成比例。不同尾矿库估计的甲烷流出率存在很大差异，超过三个数量级。这种差异最终可能是由于不同的管理决策造成的，例如使用特定的提取化学品、添加石膏等矿物质作为絮凝剂、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。最高的甲烷通量是从最古老的活跃池塘测得的。这些数据表明，随着年龄的增长，池塘可能会产生更多的甲烷，但特定的管理决策可能使我们能够通过对存在的甲烷循环微生物群落进行生物工程来限制甲烷的排放。本研究的目的是检查各种油砂尾矿池中的甲烷通量，并了解哪些因素控制甲烷产生和甲烷氧化的相关微生物过程。具体来说，我们将： 1. 评估甲烷氧化菌去除不同尾矿库中甲烷的有效性 2. 确定尾矿库中是否发生厌氧甲烷氧化，并确定负责需氧和厌氧甲烷氧化的微生物 3。比较不同油砂尾矿池的甲烷产量和氧化率，评估可能影响甲烷生成和甲烷氧化菌的管理因素 4. 估计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。结果将为尾矿库的管理提供信息，以最大限度地减少甲烷排放。