Photosynthetically-enhanced eco-engineered treatment systems

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The biological treatment of contaminated effluents in cold climate regions is one of the greatest challenges for environmental engineers, as these systems, although considered robust, can be subject to significant fluctuations in contaminant loadings, as well as ambient climate conditions, which can ultimately affect their performance. These factors are compounded in small, remote and rural areas where the use of conventional treatment systems is not logistically or economically feasible, and passive, semi-passive or naturalized treatment systems are the most suitable alternative by virtue of their ease of operation, minimal energy input, reduced maintenance requirements. In the next decade, increasingly efficient treatment systems, designed to operate under temperate conditions, will be required to meet increasingly stringent effluent discharge guidelines and minimize detrimental effects on receiving environments. Although used extensively, concerns associated with the long-term performance and functional reliability of these systems compared to conventional, but less sustainable, treatment systems have been raised. However, these challenges may be largely addressed by the implementation of carefully designed and integrated biological processes in eco-engineered systems. The proposed research program aims to address the following question: can photosynthetic organisms be employed in integrated eco-engineered treatment systems located in small, remote or isolated areas to mitigate persistent organic (Theme A) or metal (Theme B) contaminants. More specifically, the research aims to 1) examine the role of algae in enhancing photobiological degradation of persistent organic contaminants (POCs); 2) enhance the removal of POCs using suspended and attached growth algal systems; 3) enhance the mitigation of metal-rich wastewaters using N-fixing cyanobacteria; 4) enhance microbially-induced calcite precipitation (MICP) to stabilize metals in tailings; 5) integrate N-fixing cyanobacteria with MICP and sulfate reducing bacteria (SRB) to mitigate mine drainage. This program will train 5 PhD, 2 MSc and 6 UG. Critical factors limiting the widespread adoption of eco-engineered treatment technologies have been the lack of a standardized understanding of temperature and water chemistry effects on treatment process mechanisms within these systems, and a more robust basis of comparison within and between systems as they evolve with time. Hence, a focus will be placed on better understanding the dynamic interactions influencing the performance, enabling the development of a toolkit which would lead to more robust design guidelines that follow an evidence-based approach. This could be a great benefit to the Canadian mining and oil and gas industry who are often located in remote or isolated sites, and produce large volumes of processing effluents which require subsequent treatment prior to water reuse or discharge to receiving environments.