Yukon College Home Research & Innovation Bioremediation Research Project - 2013 Results

Bioremediation Research Project - 2013 Results

Bioremediation Research Project - 2013 Results

Amelie Janin

Passive water treatment has been identified as one of the areas of focus by the four partners who likely plan to use some sort of biological passive treatment systems at closure (closure plans of Minto, Wolverine, Bellekeno, and likely Eagle Gold) or during operation (Wolverine Mine, possibly Eagle Gold) whether this is wetlands, anaerobic bioreactors, electro-biochemical reactor or a combination of these techniques. Using passive biological treatment at mines in the North can be challenging due to the regulators lacking confidence in this type of technology due to limited Northern operational experience in applying these systems. A common concern relates to the efficiency of biological systems at cold temperature. To address that particular issue, research was conducted through the Chair program, starting in January 2013, to assess and compare different substrates for their potential to support bioreactor efficiencies. Substrates (biochars and wood products) were compared for their ability to remove metals by sorption as well as for organic carbon release in the effluent. Eight lab-scale bioreactors were installed and monitored since then to demonstrate their efficiencies and compare substrates. The first set of 4 bioreactors used creek sediment from Keno Hill District (KHD) and is treating synthetic water containing high concentrations of As, Cd, Cu, Se and Zn to encompass the common metals found at the different partner sites. This set has been in operation for more than 5 months to date. The other set of four used creek sediment from Wolverine creek and is treating true mine effluent from this site with a particular focus on selenium. This set has been in operation for 1 month. Results from the substrate assessment and from the monitoring of the bioreactors are reported here. The four KHD bioreactors all displayed a very high efficiency for As, Cd, Cu, Se and Zn with concentrations in the effluent lower than discharge limits except the wood-amended reactor. Low pH may have been the limiting factor in this bioreactor.