Constructed wetland treatment systems (CWTS) are one of the very few scalable and cost-effective methods to clean up large volumes of wastewaters. An in-depth understanding of how these nature-based, passive systems operate to treat industrial waste is needed to enhance treatment efficacy, particularly in northern environments that are challenged by short summers and cold winters. In the Athabasca region of northern Alberta, the surface mining of oil sands, while contributing significantly to Canada’s gross domestic product and economic development, produces large volumes of oil sands process-affected water (OSPW) that has accumulated on site in tailings ponds (currently exceeding one billion m3). Recent legislation has outlined a reclamation closure timeframe for oil sands operators to restore the landscape. Efficient and large-scale OSPW remediation technologies must be made available to address these challenges.
The presence of organic compounds, in particular a broad family of organic compounds called naphthenic acids (NAs), are major contributors responsible for the toxicity of OSPW. This research project targets the reduction of OSPW toxicity through biodegradation processes involving cooperative processes between naturally occurring microbial communities and wetland plants in CWTS. However, the conditions required to establish optimal wetland biological communities to degrade and detoxify OSPW contaminants are not well understood.
This project will apply genomics-based methods to enhance and inform the efficacy of CWTS for the treatment of OSPW. Using both mesocosm-scale and an in-situ pilot scale CWTS, genomics, microbiological and chemical analyses we will: (1) identify the conditions for enhanced NA biodegradation; (2) increase our understanding of the genes/mechanisms associated with the biodegradation of NAs; (3) develop new genomics-based tools and passive sampler methods to monitor concentrations and toxicity of NAs and other OSPW contaminants; (4) develop models of CWTS treatment of NAs and other OSPW contaminants to optimize the effectiveness of wetland design; and (5) integrate emerging experimental findings with sophisticated social science methods to expand social, legal, economic, and policy frontiers in the treatment and release of OSPW.
Informed by genomics approaches and leveraging the benefits of CWTS, the proposed applied research will provide insight on the mechanisms of plant-microbe interactions to facilitate the development of a robust, ‘green’ and cost-effective system for the remediation of OSPW. Implications of genomics in society have been integrated in each activity to guide CWTS development and address perspectives of CWTS implementation from social, economic and legal perspectives.