Bio-electrochemical treatment of mature fine tailings

阿尔伯塔油砂中成熟细尾渣的积累是一个重大的环境挑战。尾矿库可以释放出有机污染物生物降解形成的甲烷等温室气体。尾矿库也为有毒污染物进入环境提供了潜在的途径。因此，需要新的解决办法来更快地修复尾矿库。众所周知，尾矿中的细粘土颗粒会形成凝胶状网络，因此固体的沉降和固结可能需要数十年的时间。快速修复需要破坏凝胶网络的稳定性，这通常可以通过添加化学品来实现，这可能是高成本和潜在的环境影响。近年来发现电动力修复是一种有效的修复方法，但该技术难以规模化且能耗较高。本项目主要研究和评价一种新型的生物电化学处理油砂尾矿的工艺。利用天然存在于尾矿中的微生物，在金属或碳电极上培养生物膜。通过选择合适的电极材料，控制电极电位，调节生物电化学处理过程，巩固和修饰尾矿的物理、化学和生物特性。在我们实验室进行的初步结果表明，使用这种技术可以在非常低的能耗下实现成熟细粒尾矿的快速固结。在本项目中，我们将研究生物电化学处理对尾矿气体排放的影响，以及尾矿的物理、化学和生物特性。

The accumulation of mature fine tailings in the Alberta oil-sands is a significant environmental challenge. Tailings ponds can release greenhouse gases such as methane formed due to biological degradation of organic contaminants. The tailings ponds also provide a potential pathway for toxic contaminants in to the environment. New solutions are thus needed to more rapidly remediate tailings ponds. Fine clay particles in the tailings are known to form a gel like network, so that settlement and consolidation of the solids can take many decades. Rapid remediation requires destabilization of the gel network, and typically this can be achieved by addition of chemicals, which can be high cost with potential environmental impacts. Recently electrokinetic remediation has been found to be effective, however the technology is difficult to scale and has relatively high energy consumption. This project involves investigation and evaluation of a novel bio-electrochemical treatment process for remediation of oil-sands tailings. Biofilms are cultivated on metal or carbon electrodes, using the micro-organisms that are naturally present in the tailings. By selection of suitable electrode materials, and control of the electrode potential, the bio-electrochemical treatment process can be tuned to consolidate and modify the physical, chemical, and biological characteristics of the tailings. Preliminary results performed in our laboratory have indicated that rapid consolidation of mature fine tailings can be achieved using this technology at very low energy consumption. In this project, we will investigate the impact of the bio-electrochemical treatment on the gaseous emissions, and the physical, chemical and biological characteristics of the tailings.