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.

艾伯塔省油砂尾矿库每年逃逸的甲烷排放总量估计为2.3公吨二氧化碳。加拿大的总甲烷排放预算为每年92公吨二氧化碳，这意味着尾矿库产生的甲烷总量与其110平方公里的微小表面积相比非常不成比例。从不同尾矿库估算的甲烷外流速率有很大的范围，超过三个数量级。这种差异可能最终归因于不同的管理决策，如使用特定的提取化学品、添加石膏等矿物作为絮凝剂、水循环管理和池塘年龄，所有这些都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，池塘可能会随着年龄的增长而变得更多产甲烷，但特定的管理决策可能会让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。这项研究的目的是研究不同油砂尾矿库中的甲烷通量，并了解是什么因素控制着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.评估甲烷厌氧菌去除不同尾矿库中甲烷的效果2.确定尾矿库中是否发生厌氧甲烷氧化，并确定哪些微生物同时对好氧和厌氧甲烷氧化负责。比较不同油砂尾矿库的甲烷产量和氧化率，评估可能影响甲烷生成和甲烷营养的管理因素4.评估添加氧化还原活性氧化铁矿物作为抑制甲烷菌和刺激厌氧甲烷养殖体的策略的有效性加拿大油砂创新联盟将为这项研究提供现场样本和实验室分析。研究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。