Passive Biochemical Reactors (PBRs) are an effective and promising technology for the treatment of mine drainage (MD) with moderate contamination in temperate or semi-arid climates. However, their performance is poorly known in northern climates, characterized by low temperatures (<4ºC) and, often, high salinities (up to 40 g/L), in addition to the highly variable quality of MD.
PBRs are generally filled with reactive mixtures consisting of a neutralizing material, a source of organic matter, a source of bacteria and a structural agent. The choice of the reactive mixtures composition depends essentially on the MD quality as well as the operating conditions employed. These may favor some treatment mechanisms over others (sorption vs. precipitation). In order to evaluate the effectiveness of the PBRs in northern climate, a first step of the project consists in selecting the qualities of the MD to be treated, then the raw materials available on the mine site (industrial partner of the project) and nearby, that will serve as reactive mixtures for the PBRs. Following their characterization, batch tests will be carried out in order to select the composition of the most effective reactive mixtures. Then, column tests will be conducted to select the hydraulic residence time and determine the porosity evolution of the selected mixtures. Finally, all the data collected (in the laboratory as well as in the field) will be used in the calibration of numerical simulations series. The overall findings would allow evaluating the long term efficiency and stability of the treatment system in order to optimize the mine site reclamation.