title: Removal of strontium from drinking water by conventional treatment and lime softening in bench-scale studies.
abstract: The United States Environmental Protection Agency Contaminant Candidate List 3 lists strontium as a contaminant for potential regulatory consideration in drinking water. Very limited data is available on strontium removal from drinking water and as a result, there is an immediate need for treatment information. The objective of this work is to evaluate the effectiveness of coagulation/filtration and lime-soda ash softening treatment methods to remove strontium from surface and ground waters. Coagulation/filtration jar test results on natural waters showed that conventional treatment with aluminum and iron coagulants were able to achieve only 12% and 5.9% strontium removal, while lime softening removed as high as 78% from natural strontium-containing ground water. Controlled batch experiments on synthetic water showed that strontium removal during the lime-soda ash softening was affected by pH, calcium concentration and dissolved inorganic carbon concentration. In all softening jar tests, the final strontium concentration was directly related to the initial strontium concentration and the removal of strontium was directly associated with calcium removal. Precipitated solids showed well-formed crystals or agglomerates of mixed solids, two polymorphs of calcium carbonate (vaterite and calcite), and strontianite, depending on initial water quality conditions. X-ray diffraction analysis suggested that strontium was likely incorporated in the calcium carbonate crystal lattice and was likely responsible for removal during lime softening.
authors.affiliation: University of Cincinnati, Department of Biomedical, Chemical, and Environmental Engineering, 601 Engineering Research Center, Cincinnati, OH 45221-0012, United States.
authors.forename: Alissa J
authors.initials: AJ
authors.lastname: O'Donnell
authors.affiliation: U.S. Environmental Protection Agency, ORD, NRMRL, WSWRD, 26 W. Martin Luther King Dr., Cincinnati, OH 45268, United States. Electronic address: lytle.darren@epa.gov.
authors.forename: Darren A
authors.initials: DA
authors.lastname: Lytle
authors.affiliation: U.S. Environmental Protection Agency, ORD, NRMRL, WSWRD, 26 W. Martin Luther King Dr., Cincinnati, OH 45268, United States.
authors.forename: Stephen
authors.initials: S
authors.lastname: Harmon
authors.affiliation: Macaulay Honors College at City College of New York, Civil Engineering Department, 160 Convent Ave., New York, NY 10031, United States.
authors.forename: Kevin
authors.initials: K
authors.lastname: Vu
authors.affiliation: University of Illinois at Urbana-Champaign, Department of Chemical and Biomolecular Engineering, 600 S. Matthews Ave., Urbana, IL 61801, United States.
authors.forename: Hannah
authors.initials: H
authors.lastname: Chait
authors.affiliation: University of Cincinnati, Department of Biomedical, Chemical, and Environmental Engineering, 601 Engineering Research Center, Cincinnati, OH 45221-0012, United States.
authors.forename: Dionysios D
authors.initials: DD
authors.lastname: Dionysiou
mesh_terms: D060766:Drinking Water; D013324:Strontium; D018508:Water Purification; D014880:Water Softening; D014961:X-Ray Diffraction
chemical_list: D060766:Drinking Water; D013324:Strontium
keywords: Coagulation; Drinking water; Jar test; Lime softening; Strontium