British Columbia Mine Reclamation Symposium

Case study : performance of the operating demonstration-scale constructed wetland treatment system at Minto Mine Bouchard, E.; Prentice, C.; Herbert, R.; Martz, R.; Eisner, B.; Friesen, V.; Simair, M.


The Minto Mine is following a phased approach for the design and implementation of a Constructed Wetland Treatment System (CWTS) for water treatment at closure. The CWTS is currently in the demonstration‐scale and optimization stage preceding full-scale implementation. The CWTS has successfully treated constituents of potential concern in the mine site’s sub‐arctic continental climate. Carex aquatilis (aquatic sedge) and aquatic mosses (bryophytes) from natural wetlands onsite were used for planting, while water mine‐impacted seepage water was used as feed water. The CWTS was designed to target specific physicochemical parameters for treatment (confirmed and refined through off‐site pilot‐scale testing), which enable denitrifying, selenium-, and sulfate‐reducing bacteria to treat nutrients, metals and metalloids in the water. The CWTS treated targeted constituents of potential concern in the following extents and percentages (averages): cadmium 80% (from 0.0261 μg/L to 0.0092 μg/L), copper 65% (from 49.1 μg/L to 17.3 μg/L), molybdenum 58% (from 6.3 μg/L to 2.7 μg/L), selenium 89% (from 4.0 μg/L to 0.5 μg/L), zinc 98% (from 49.2 μg/L to 1.9 μg/L), and nitrate as N 97% (from 6.5 mg/L to 0.19 mg/L). Continued trials are underway in 2018 to investigate treatment under a wider range of operational conditions.

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