Jan. 26, 2024: Citizens and scientists in northern Minnesota learned about a recent breakthrough in the Clearwater Biologic sulfate cleanup system, which has strong potential to heal the mining-impacted waters of that region. Jeffrey Hanson’s Jan. 16 presentation to the Boundary Waters Connection’s Tuesday Group in Ely can be viewed here: Bio-Bugs and Iron for Sulfate Removal and Zebra Mussel Control.
As Hanson explains, it’s the latter part of the multi-step process that has been dramatically improved. Once sulfate-reducing bacteria (“bio-bugs”) have converted sulfate to hydrogen sulfide, Hanson has found that direct-reduced iron— a future local resource— can be used along with electrolysis to convert it to iron sulfide, with bench tests showing consistent results. Once precipitated out, the iron sulfide even yields marketable byproducts. Hanson plans to field-test the improved process in mine-pit lakes on the Iron Range.
Another source: Read Marshall Helmberger’s summary of the improved process in the Timberjay, Oct. 26, 2023: Babbitt engineer patenting a low-cost solution to sulfate pollution online.