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Field application of calcite Dispersed Alkaline Substrate (calcite-DAS) for passive treatment of acid mine drainage with high Al and metal concentrations

Lookup NU author(s): Dr Tobias Roetting, Manuel Caraballo Monge

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Abstract

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.

Publication metadata

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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