Water Resources Research Act Program

Details for Project ID 2016MT307B

Student Fellowship: Removal of selenium by co-precipitation with microbially induced calcite precipitation

Institute: Montana
Year Established: 2016 Start Date: 2016-03-01 End Date: 2017-02-28
Total Federal Funds: $1,000 Total Non-Federal Funds: $440

Principal Investigators: Neerja Zambare

Abstract: Although a lot of research goes into alternative, renewable energy sources, coal still remains the major energy source for electricity generation in the U. S. In 2014, 39% of the electricity generated in the US was from coal1. Coal mining exposes rocks which have naturally occurring elements like selenium. When these rocks, called ‘overburden’, are exposed to water, the selenium leaches out. This leads to the release of large amounts of selenium through waste streams. Selenium is bio-accumulable and causes deformities and reproductive issues in fish2. In humans, selenium toxicity causes gastrointestinal disturbances, nail and hair loss and dermatitis, and neurotoxicity3. The state of Montana still depends heavily on coal as the primary energy source. The number one energy source in Montana in 2013 was coal, with usage estimated at over 150 trillion BTU 4. Coal-fired electricity generation was considerably higher than generation by any other source4. With such high levels of coal usage in Montana, selenium pollution is a growing concern. A 2012 study at the University of Montana established that coal mining has been the cause for selenium pollution in the Elk River5. Even with the possibility of moving away from fossil fuels to renewable sources of energy, old coal mines will still remain a threat because their leachate will serve as a selenium contaminant source. Previous research has shown that it is possible for selenium to incorporate into calcite6. In this previous study, calcite production was abiotic. This research will focus on biologically aided removal of selenium. Sporosarcina pasteurii is a bacterium that can induce calcite precipitation via ureolysis7. Ureolysis is the breakdown of urea into ammonium and carbonate. The chemical reactions involved also influence the pH and shift the carbonate equilibrium such that calcite can precipitate out of solution in the presence of calcium. Selenium incorporation into calcite thus formed by S.pasteurii will be researched. Our lab has established contact with Talen Energy’s coal-fired power plant in Colstrip, Montana. Water samples collected from the wastewater ponds at this power plant will be the focus of this research.