Evaluating the biogeochemistry of oil sands tailings in end pit lakes

油砂是加拿大经济的重要组成部分；然而，油砂作业对环境的影响也越来越大。尾矿库几乎完全用于废物管理，总占地面积超过220平方公里。经过加工的油砂矿石产生的尾矿浆被排放到沉降池中，最终必须回收并纳入矿井关闭景观。然而，由于尾矿的低固体/高粘土含量，它们脱水缓慢，使得油砂尾矿的回收特别具有挑战性。一种被提出的回收方法是尾坑湖（EPLs），它涉及在退役的露天矿中沉积有水覆盖的厚层尾矿。从理论上讲，epl是一种合适的回收策略，因为尾矿可以缓慢脱水，而水帽可以作为水生生态系统的栖息地。然而，EPL的第一次全面演示表明，该策略存在一些挑战，包括浊度的产生和水帽质量。因此，建议在epl中沉淀混凝剂（明矾）和絮凝剂（聚丙烯酰胺，PAM）尾矿，以改善尾矿脱水，减少浊度的产生。这种技术被称为永久性水生储存结构（PASS）。迄今为止，在epl中沉积经过pass处理的尾矿的生物地球化学意义尚不清楚，PAM、PAM降解产物和铝的生物降解和环境命运也不清楚。该项目将阐明未处理和处理过的尾矿在epl中的生物地球化学行为，并将评估epl是否是一种合适的、对环境负责的尾矿回收策略。研究了PAM在处理后油砂尾矿中的生物降解情况，并评价了未处理和处理后油砂尾矿的生物地球化学演化。油砂尾矿中特有微生物的微观研究将研究pam处理后的尾矿在好氧和厌氧条件下的生物降解情况。我以前的研究现在已经发展成几十年的知识在研究复杂的厌氧生物修复系统和独特的定位我们来解决这个同样复杂的PAM生物修复系统。随着未来50年油砂矿的关闭，了解当前尾矿回收做法的长期影响至关重要。拟议的研究将提供有关利用环境污染物质进行填海的生物地球化学影响的重要资料。从这项研究中获得的知识将有助于查明和减少矿山关闭做法对环境的长期影响，并将指导今后的研究和发展。确保拟议的研究项目向油砂工业提供作出健全的尾矿管理和矿山关闭规划决定所需的信息，符合加拿大人的既得利益。

The oil sands are a vital component to the Canadian economy; however, the environmental impacts of oil sands operations are also growing. Tailings impoundments are used almost exclusively for waste management with a combined footprint more than 220 km2. Processed oil sands ore yields tailings slurries that are discharged into a settling basin and must eventually be reclaimed and integrated into mine closure landscapes. However, due to the low solids/high clay content of tailings, they are slow to dewater, making reclamation of oil sands tailings particularly challenging. One proposed reclamation method is end pit lakes (EPLs), which involve depositing thick layers of tailings capped with water in decommissioned open pits. Theoretically, EPLs are a suitable reclamation strategy because the tailings can slowly dewater while the water cap serves as habitat for an aquatic ecosystem. However, the first full-scale demonstration EPL showed that there are several challenges with this strategy, including turbidity generation and water cap quality. As such, depositing coagulant- (alum) and flocculant-treated (polyacrylamide, PAM) tailings in EPLs was proposed to improve tailings dewatering and reduce turbidity generation. This technology is called permanent aquatic storage structure (PASS). To date, the biogeochemical implications of depositing PASS-treated tailings in EPLs remain unknown, and the biodegradation and environmental fate of PAM, PAM degradation products, and aluminum are not well understood. This program will elucidate the biogeochemical behavior of untreated and treated tailings in EPLs and will evaluate whether EPLs are a suitable, environmentally responsible tailings reclamation strategy. The objectives of these studies are to investigate PAM biodegradation in treated oil sands tailings, and evaluate the biogeochemical evolution of untreated and treated oil sands tailings in EPLs. Microcosm studies with microorganisms indigenous to oil sands tailings will investigate biodegradation in PAM-treated tailings under aerobic and anaerobic conditions. My previous research has now developed into decades worth of knowledge in studying complex anaerobic bioremediation systems and uniquely positions us to tackle this equally complex PAM bioremediation system. With upcoming oil sands mine closures over the next 50 years, it is vital to understand the long-term effects of current tailings reclamation practices. The proposed research will provide critical information on the biogeochemical implications of using EPLs for reclamation. The knowledge gained from this research will assist in identifying and reducing the long-term environmental impacts of mine closure practices and will guide future research and development. Canadians have a vested interest in ensuring the proposed research project provides the oil sands industry with information needed to make sound tailings management and mine closure planning decisions.