Grant: CCI Applied Research and Development Grants

Polymeric flocculants, such as polyacrylamide (PAM), play a vital role in water treatment and waste management, aiding in the aggregation and removal of suspended particles. The oil sands industry, particularly in tailings treatment, relies heavily on these flocculants, using high dosages ranging from 1000-2000 g/t solids due to the complex nature of tailings. Industry concerns have arisen regarding the long-term environmental impact of this significant polymer usage, and their degradation over time, including geotechnical property changes, water quality, and biogenic gas generation, posing challenges to water quality and ecosystem health. Suncor Energy Inc., a Canadian oil sands industry leader, manages a substantial fluid tailings inventory that demands effective treatment for accelerated reclamation and closure. Their Permanent Aquatic Storage Structure (PASS) treatment process involves treating fluid fine tailings (FFT) with coagulants and polymer flocculants like PAM, subsequently depositing the treated material into a mined-out pit and capping it with fresh water for aquatic closure in the form of an end pit lake. Microbial interaction with polymeric flocculants in end pit lakes is an emerging concern in the oil sands industry. Microorganisms can metabolize nitrogen in PAM molecules, releasing ammonia and posing risks to aquatic life and water quality. Microbial activity may also produce biogenic gases like methane, potentially disrupting the PASS tailings treatment process and leading to turbidity and the release of residual bitumen. Given these challenges, the Northern Alberta Institute of Technology (NAIT), the University of Calgary (UofC), and Suncor will collaborate to develop a standardized laboratory method to assess polymer flocculant biodegradation within FFT. This method will enable Suncor to identify and exclude polymer candidates from the PASS program that exhibit not only poor FFT dewatering performance, but also ones that contribute to the biogenic production of greenhouse gases or have other undesirable degradation products. Ultimately, our results will enhance Suncor's flocculant screening protocol for sustainable oil sands tailings management and reclamation, in turn addressing environmental and community concerns associated with oil sands operations.