title: Evaluating the cement stabilization of arsenic-bearing iron wastes from drinking water treatment.
abstract: Cement stabilization of arsenic-bearing wastes is recommended to limit arsenic release from wastes following disposal. Such stabilization has been demonstrated to reduce the arsenic concentration in the Toxicity Characteristic Leaching Procedure (TCLP), which regulates landfill disposal of arsenic waste. However, few studies have evaluated leaching from actual wastes under conditions similar to ultimate disposal environments. In this study, land disposal in areas where flooding is likely was simulated to test arsenic release from cement stabilized arsenic-bearing iron oxide wastes. After 406 days submersed in chemically simulated rainwater, <0.4% of total arsenic was leached, which was comparable to the amount leached during the TCLP (<0.3%). Short-term (18 h) modified TCLP tests (pH 3-12) found that cement stabilization lowered arsenic leaching at high pH, but increased leaching at pH<4.2 compared to non-stabilized wastes. Presenting the first characterization of cement stabilized waste using μXRF, these results revealed the majority of arsenic in cement stabilized waste remained associated with iron. This distribution of arsenic differed from previous observations of calcium-arsenic solid phases when arsenic salts were stabilized with cement, illustrating that the initial waste form influences the stabilized form. Overall, cement stabilization is effective for arsenic-bearing wastes when acidic conditions can be avoided.
authors.affiliation: Department of Civil & Environmental Engineering, University of Michigan, Ann Arbor, MI 48109, United States.
authors.forename: Tara M
authors.initials: TM
authors.lastname: Clancy
authors.affiliation: Department of Civil & Environmental Engineering, University of Michigan, Ann Arbor, MI 48109, United States.
authors.forename: Kathryn V
authors.initials: KV
authors.lastname: Snyder
authors.affiliation: Department of Civil & Environmental Engineering, University of Michigan, Ann Arbor, MI 48109, United States.
authors.forename: Raghav
authors.initials: R
authors.lastname: Reddy
authors.affiliation: Center for Advanced Radiation Sources, University of Chicago, Chicago, IL 60637, United States.
authors.forename: Antonio
authors.initials: A
authors.lastname: Lanzirotti
authors.affiliation: Department of Civil & Environmental Engineering, University of California at Berkeley, Berkeley, CA 94720, United States.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Amrose
authors.affiliation: Department of Civil & Environmental Engineering, University of Michigan, Ann Arbor, MI 48109, United States.
authors.forename: Lutgarde
authors.initials: L
authors.lastname: Raskin
authors.affiliation: Department of Civil & Environmental Engineering, University of Michigan, Ann Arbor, MI 48109, United States. Electronic address: ford@umich.edu.
authors.forename: Kim F
authors.initials: KF
authors.lastname: Hayes
mesh_terms: D001151:Arsenic / Q000032:analysis*; D003252:Construction Materials; D060766:Drinking Water / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste / Q000032:analysis*; D007501:Iron / Q000032:analysis*; D012972:Sodium Hydroxide / Q000737:chemistry; D012995:Solubility; D064091:Waste Disposal Facilities; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*
chemical_list: D060766:Drinking Water; D007220:Industrial Waste; D014874:Water Pollutants, Chemical; D012972:Sodium Hydroxide; D007501:Iron; D001151:Arsenic
keywords: Arsenic; Cement stabilization; Toxicity Characteristic Leaching Procedure