title: Effects of Simulated Rare Earth Recycling Wastewaters on Biological Nitrification.
abstract: Increasing rare earth element (REE) supplies by recycling and expanded ore processing will result in generation of new wastewaters. In some cases, disposal to a sewage treatment plant may be favored, but plant performance must be maintained. To assess the potential effects of such wastewaters on biological treatment, model nitrifying organisms Nitrosomonas europaea and Nitrobacter winogradskyi were exposed to simulated wastewaters containing varying levels of yttrium or europium (10, 50, and 100 ppm), and the extractant tributyl phosphate (TBP, at 0.1 g/L). Y and Eu additions at 50 and 100 ppm inhibited N. europaea, even when virtually all of the REE was insoluble. Provision of TBP with Eu increased N. europaea inhibition, although TBP alone did not substantially alter activity. For N. winogradskyi cultures, Eu or Y additions at all tested levels induced significant inhibition, and nitrification shut down completely with TBP addition. REE solubility was calculated using the previously developed MSE (Mixed-Solvent Electrolyte) thermodynamic model. The model calculations reveal a strong pH dependence of solubility, typically controlled by the precipitation of REE hydroxides but also likely affected by the formation of unknown phosphate phases, which determined aqueous concentrations experienced by the microorganisms.
authors.affiliation: †Idaho National Laboratory, Idaho Falls, Idaho 83415, United States.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Fujita
authors.affiliation: †Idaho National Laboratory, Idaho Falls, Idaho 83415, United States.
authors.forename: Joni
authors.initials: J
authors.lastname: Barnes
authors.affiliation: ‡OLI Systems, Inc., 240 Cedar Knolls Road, Suite 301, Cedar Knolls, New Jersey 07927, United States.
authors.forename: Ali
authors.initials: A
authors.lastname: Eslamimanesh
authors.affiliation: ‡OLI Systems, Inc., 240 Cedar Knolls Road, Suite 301, Cedar Knolls, New Jersey 07927, United States.
authors.forename: Malgorzata M
authors.initials: MM
authors.lastname: Lencka
authors.affiliation: ‡OLI Systems, Inc., 240 Cedar Knolls Road, Suite 301, Cedar Knolls, New Jersey 07927, United States.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Anderko
authors.affiliation: §Department of Materials Science and Engineering, Rutgers, The State University of New Jersey, 607 Taylor Road, Piscataway, New Jersey 08855, United States.
authors.forename: Richard E
authors.initials: RE
authors.lastname: Riman
authors.affiliation: ∥Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California Davis, Davis, California 95616, United States.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Navrotsky
mesh_terms: D000641:Ammonia / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008674:Metals, Rare Earth / Q000737:chemistry*; D058465:Nitrification / Q000187:drug effects; D009573:Nitrites / Q000494:pharmacology; D009576:Nitrobacter / Q000187:drug effects; D043370:Nitrosomonas europaea / Q000187:drug effects; D010755:Organophosphates / Q000494:pharmacology; D010084:Oxidation-Reduction / Q000187:drug effects; D059027:Recycling; D012995:Solubility; D012996:Solutions; D013816:Thermodynamics; D062065:Wastewater / Q000737:chemistry*
chemical_list: D000641:Ammonia; D008674:Metals, Rare Earth; D009573:Nitrites; D010755:Organophosphates; D012996:Solutions; D062065:Wastewater; C009524:tributyl phosphate