"Environment" research area

Engineered Biochars for Sulfate Removal from Mining Waters

Primary Investigator - Sebastian BehrensPrimary InvestigatorSebastian Behrens
Co-Investigators: 
Kurt Spokas
Industry PartnersAmerican Peat Technology; Global Mineral Engineering; Minnesota Department of Natural Resources
Award Type: Seed Grant - Postdoctoral Research Scholar

Problem: Mining operations in Northeastern Minnesota, and particularly copper-nickel and iron mineral mining, discharge water to the surrounding environment with high sulfate and heavy metal concentrations. Given the unique positioning within the regional hydrologic system, this contaminated water threatens the ecosystems of the Mississippi River, Lake Superior, and Rainy River watersheds. Prior research has shown high levels of sulfate and heavy metals to be toxic to plants and wildlife, such as wild rice and lake trout. With expanded mining operations proposed, it is critical that remediation technology and tools keep pace, and prevent these contaminants from entering Minnesota waterways.

Solution: The Behrens Lab is developing a low-cost, biochar-based material that absorbs sulfate and heavy metals and removes them from water. Biochar is a plant-derived porous media that will be enriched with iron and manganese to enhance it’s adsorptive properties relative to these contaminants. The adsorptive performance of the biochar will be evaluated and compared to other commercially available sorptive media. The team will thus be able to assess the effectiveness and efficacy of this lower-cost option.

Impact: Iron and manganese enriched biochar is a relatively simple and low-cost solution for removal of sulfate and heavy metals from water. Iron’s magnetic properties not only enhance removal of heavy metals, but also the potential for recovery of these valuable metals from the biochar media, contaminated soil or sediment. Removal of sulfate and heavy metals will also begin remediating the impacted waters that support a culturally and economically important wild rice “manoomin” industry in northern Minnesota.