Smart Bioremediation Technology to Achieve High Sulfate Reduction in Mining Waters of NE Minnesota - Phase 1 Report

Abstract

There exists a significant need in northeastern Minnesota to provide a viable solution to the current challenge of maintaining existing iron ore and developing non-ferrous mining industries while simultaneously protecting watersheds from elevated aqueous sulfate concentrations that could prove detrimental to biota, especially wild rice. ”Smart Bioremediation Technology to Achieve High Sulfate Reduction in Mining Waters of NE Minnesota – Phase I” focuses on proof of concept early-stage development of a realistic solution to the aqueous sulfate issue potentially threatening Minnesota’s existing $3 billion/year ferrous mining industry as well as Minnesota’s projected $4 billion/year non-ferrous mining industry (Skurla, 2012). Initial funding was provided for this Phase I work by the Natural Resources Research Institute (NRRI) and an Innovation Grant from the Laurentian Vision Partnership through the East Range Joint Powers Board. The design of the technology included smart sensors and controls which enabled remote operation and monitoring of the pilot scale system. Solar panels mounted on the systems floating bioreactor modules provided DC power to operate embedded pumps, sensors, controls, and data transmitters. The system was designed to enable stand alone, year round remote operation in environmental conditions encountered in either operating or legacy mining operations across the U.S. The modular nature of the technical design allows for practical scale up to accommodate flow requirement needs for the mining industry. The robust system design combined biological sulfate reduction with remediation hydrogeology approaches to remove sulfur from mining impacted waters (Reinsel, 2015). Sulfate reducing bacteria (SRB) from local stream sediments were utilized to provide the sulfate reduction. Preliminary analytical results indicate that the smart bioremediation technology is capable of producing aqueous sulfate reduction in the mining waters flowing through the bioreactor systems. The Phase I project has provided a proof of concept design for remediation of sulfate in mining impacted waters. Additional studies (Phase II study and MN Drive study) are currently under way and will be delivered during summer, 2016. The purpose of these future studies is to deliver a smart technology bioremediation water treatment system that is capable of being commercialized and that can effectively decrease aqueous sulfate levels in impacted waters in a cost-effective manner to concentrations that can be further decreased by other technologies so that stringent aqueous sulfate concentrations can be achieved.