Evaluating the cement stabilization of arsenic-bearing iron wastes from drinking water treatment

JOURNAL OF HAZARDOUS MATERIALS

卷:300

Article

Clancy, Tara M.¹  Snyder, Kathryn V.¹  Reddy, Raghav¹  Lanzirotti, Antonio²  Amrose, Susan E.³  Raskin, Lutgarde¹  Hayes, Kim F.¹ 

[1] Univ Michigan, Dept Civil & Environm Engn, Ann Arbor, MI 48109 USA

[2] Univ Chicago, Ctr Adv Radiat Sources, Chicago, IL 60637 USA

[3] Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA

关键词: Arsenic;    Cement stabilization;    Toxicity Characteristic Leaching Procedure;   

DOI  :  10.1016/j.jhazmat.2015.07.051

来源: Elsevier

【 摘 要 】

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 mu XRF, 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. (C) 2015 Elsevier B.V. All rights reserved.

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