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Lookup NU author(s): Dr Tobias Roetting, Manuel Caraballo Monge
Passive treatment systems are widely used for remediation of acid mine drainage (AMD), but existing designs are prone to clogging or loss of reactivity due to Al- and Fe-precipitates when treating water with high Al and heavy metal concentrations. Dispersed alkaline substrate (DAS) mixed from a fine-grained alkaline reagent (e.g. calcite sand) and a coarse inert matrix (e.g. wood chips) had shown high reactivity and good hydraulic properties in previous laboratory column tests. In the present study, DAS was tested at pilot field scale in the Iberian Pyrite Belt (SW Spain) on metal mine drainage with pH near 3.3, net acidity 1400-1650 mg/L as CaCO3, and mean concentrations of 317 mg/L Fe (95% Fe(II)), 311 mg/L Zn, 74 mg/L Al, 20 mg/L Mn, and 1.5-0.1 mg/L Cu, Co, Ni, Cd, As and Pb. The DAS-tank removed an average of 870 mg/L net acidity as CaCO3 (56% of inflow), 25% Fe, 93% Al, 5% Zn, 95% Cu, 99% As, 98% Pb, and 14% Cd, but no Mn, Ni or Co. Average gross drain pipe alkalinity was 181 mg/L as CaCO3, which increased total Fe removal to 153 mg/L (48%) in subsequent sedimentation ponds. Unfortunately, the tank suffered clogging problems due to the formation of a hardpan of Al-rich precipitates. DAS lifetime could probably be increased by lowering Al-loads. © 2008 Elsevier Ltd. All rights reserved.
Author(s): Rötting T, Caraballo M, Serrano J, Ayora C, Carrera J
Publication type: Article
Publication status: Published
Journal: Applied Geochemistry
Year: 2008
Volume: 23
Issue: 6
Pages: 1660-1674
Print publication date: 01/06/2008
ISSN (print): 0883-2927
ISSN (electronic): 1872-9134
URL: http://dx.doi.org/10.1016/j.apgeochem.2008.02.023
DOI: 10.1016/j.apgeochem.2008.02.023
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