Bioremediation in Cold Climate
Passive biological treatments have been proposed as an efficient and cost effective treatment of metal bearing water discharged from mine sites after closure. However, concerns have been expressed around biological treatments and their suitability in northern, colder climates as there are few examples of passive treatment systems operating under cold conditions which have been documented so far.
In this project, 12 laboratory scale anaerobic bioreactors and 4 pilot scale bioreactors were monitored over the duration of a year for their capacity to reduce metal concentrations at variable temperatures. The objective of this study was to support the development of bioremediation in Yukon by providing bench- and field testing of bioreactors as well as a a better understanding of the biochemical processes involved.
The project was divided in two components: 1) tailor bioreactors for operation in Yukon's cold climate by using specific, reactive, substrates and 2) testing of bioreactors for treatment of various mine water, targeting various contaminants. Many biological and chemical mechanisms arise in a bioreactor and, all together, they lead to a reduction of the metal concentration in the effluent.
This project looked at various low-cost substrates and nutrients sources which can promote specific biochemical mehanisms, such as chemical adsorption, to improve the overall efficiency and stability of the reactor. Some materials may disturb the microbiological equilibrium while some of them will result in a significant metals removal enhancement. Lab scale testing of these materials allowed for the screening of these materials while bench scale testing allowed for assessment of the performances various bioreactors. Results and knowledge aquired in the lab were then applied to field tests.
Researcher, Guillaume Nielsen, Ph.D. student
Jim Harrington, David Petkovich, Alexco Environmental Group
Martin Haefele, Capstone Mining Corp
Steve Wilbur, Victoria Gold Corp
Robin McCAll, Yukon Zinc Corp
Yukon Mine Research Consortium