"Environment" research area

Using Biological Oxidation of Sulfide to Protect the Mesabi Iron Range

Primary Investigator Jake Bailey
Co-InvestigatorsDaniel Jones
Industry PartnersClearwater Layline LLC
Award Type: Seed Grant - Postdoctoral Research Scholar 

Problem: Mining operations on the Mesabi Iron Range can elevate sulfate levels in surrounding waters, which is detrimental to wild rice. Minnesota’s strict sulfate limits put technical and economic strain on mining operations and municipal water treatment plants that discharge into wild rice waters. Standard biological sulfate treatment utilizes anaerobic microorganisms to convert sulfate to sulfide. The sulfide is then removed by adding iron, which results in the production of solid iron sulfide. The iron addition creates other environmental issues in sulfate treatment systems, such as low pH and elevated Cl- in the effluent.

Solution: Biological oxidation of sulfide, a process that uses microbes to remove sulfide from water, could replace iron addition and produce elemental sulfur (S0) as a valuable end product to be sold to other industrial processes. The Bailey Lab will investigate microbial communities and conditions that promote consistent and predictable S0 production. Using lab-scale bioreactors to simulate field conditions, they will optimize the biological oxidation process to ultimately test at pilot- or field-scale.

Impact: Maintaining low sulfate concentrations is important for Ojibwe communities in Minnesota, who rely on wild rice, or manoomin, as a culturally, economically, and spiritually important plant. Biological oxidation of sulfide to S0 could help mining companies in northern Minnesota remove sulfate with a more cost-effective, environmentally friendly process.