Characterization and treatment of comtaminants of emerging concern in mine effluents

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This project involves three universities, one research center, and four mining industry partners, and aims at the characterization and treatment of contaminants of emerging concern (CECs) in mine effluents. In the context of this study, the CECs in mine effluents include four categories: 1) new contaminants (e.g. Mn, Se, Sb); 2) common contaminants (e.g. As, Cu, Zn), but with very low target concentrations in sensitive environments, such as the cold climate; 3) difficult to treat contaminants (e.g. sulfate, salinity); and 4) nitrogen compounds (ammonia, nitrites, and nitrates). Some of these contaminants are currently monitored via aquatic toxicity assessment. Specific discharge criteria are expected in the near future, but they would be difficult to comply with because of the operational challenges for CECs treatment, including a complex chemistry, persistency, requirements of oxidizing or reducing conditions, lack of a proven BATEA, and insufficient knowledge as to the optimal efficiency conditions with mixtures of contaminants and variable effluent quality. Thus, future priorities of mining companies in water management should: 1) improve/develop sustainable treatment technologies for CECs; 2) limit residual salinity creation; and 3) produce stable sludge. The study, which aims knowledge advancing on the characterization of mine effluents and performance improvement of CECs treatment processes, is centered around 3 objectives: O1) thorough characterization of effluents from 4 active mines for CECs identification; O2) treatment of CECs, with focus on concentration and temperature; and O3) evaluation of aquatic toxicity, before and after treatment of actual mine effluents containing CECs. The methodology will consist of characterization of actual effluents, followed by treatability testing with mock and real effluents, and toxicity evaluation of the optimal performance solution. A specific goal is to develop protocols for accurate speciation analysis and treatment of CECs. The results obtained would allow, through an advanced understanding of the technological and environmental aspects, better potential applications on a large scale, on the sites of the industrial partners and elsewhere in Canada. The project will train 3 PhD and 2 PDF.