Minimization of GHG emissions in froth treatment tailing by manipulation of electron acceptors

尾矿库温室气体排放的主要来源是用于沥青回收的环烷和石蜡溶剂的生物降解，其次是残留沥青的生物降解。由于甲烷的全球变暖潜力(GWP)是二氧化碳的28-36倍，根据艾伯塔省的气候变化战略，减少或消除甲烷排放可能会带来显著的环境和经济效益，必须加以解决。CH4是在低氧化还原条件下(~-250 mV)，在没有Fe(III)和硫酸盐等其他TEA的情况下，碳氢化合物的微生物氧化与末端电子受体(TEA)(如醋酸或CO2)的还原耦合而产生的。当这类茶的浓度足够高时，甲烷生成就会受到抑制。这项建议将在实验室微观世界或生物反应器研究中，研究不同的茶叶条件、营养改良剂以及稀释剂和沥青浓度对不同类型尾矿库尾矿中生物产气量的影响。生物产气率、茶叶消耗量和碳氢化合物降解率将与未经修正的缩影进行比较。碳氢化合物降解物将被确定，这些微生物可能被用来提高降解率。其他研究将评估传质限制的影响，因为溶剂必须从沥青聚集体扩散到要生物降解的水相。这些结果将被用来开发一个耦合的传质和反应模型，该模型将提供各种TEAS/氧化还原条件下温室气体产生的基本信息。它将被用来确定主导机制，并帮助制定通过操纵池塘化学将温室气体排放降至最低的战略。根据艾伯塔省的气候变化战略，这将对工业产生重大的环境和经济利益，并在更大范围内改善加拿大和全球的环境和生活质量。研究成果还可应用于其他生态系统，如海洋和淡水沉积物，以减少温室气体的产生，并进一步有助于减少全球变暖。该项目还将为10名高素质的个人提供培训。

The main sources of greenhouse gas (GHG) emissions in tailings ponds are from the biodegradation of naphthenic and paraffinic solvents used in bitumen recovery, and to a lesser extent, of residual bitumen. Since CH4 has a global warming potential (GWP) of 28-36 times that of CO2, reducing or eliminating CH4 emissions can be of significant environmental and economic benefit under Alberta's climate change strategy and must be addressed. CH4 is produced from the microbial oxidation of hydrocarbons coupled to the reduction of terminal electron acceptors (TEAs) such as acetic acid or CO2 at low redox conditions (~ -250 mV) when other TEAs such as Fe(III) and sulphate are absent. When such TEAs are present at sufficiently high concentrations, methanogenesis is inhibited. This proposal will examine the impact of different TEA conditions, nutrient amendments and diluent and bitumen concentrations on biogenic gas production in tailings from different types of tailing ponds in laboratory microcosm or bioreactor studies. Rates of biogenic gas production, TEA consumption, and hydrocarbon degradation will be compared to unamended microcosms. The hydrocarbon degraders will be identified and these organisms could potentially be used to enhance degradation rates. Additional studies will evaluate the effect of mass transfer limitation as solvents have to diffuse out of bitumen aggregates to the aqueous phase to be biodegraded. These results will be used to develop a coupled mass transfer and reaction model that would provide basic information on GHG production under a variety of TEAs/redox conditions. It will be used to identify dominant mechanisms and aid in developing strategies to minimize GHG emissions by manipulating pond chemistry. This can have significant environmental and economic benefit to industry under Alberta's climate change strategy and on a wider scale will improve the environment and the quality of life in Canada and globally. The research outcomes may also be applied to other ecosystems such as marine and freshwater sediments to reduce GHG production and further contribute to decrease global warming. This project will also provide training to 10 highly qualified individuals.