Tratamiento pasivo de aguas ácidas con residuos generados al tratar efluentes industriales

Abstract

The “Ría de Huelva” estuary (SW Spain), is seriously polluted by acid mine leachates and phosphate fertilizer industry effluents. This work evaluates the effectiveness of calcite (CaCO3)-rich solid wastes generated during the treatment of industrial effluents with the Dispersed Alkaline Substrate (DAS) technology, for the passive treatment of highly acidic and contaminated mine waters. The study consists of flowing the mine water through a column filled with a mixture of an alkaline reactive (i.e., calcite resulting from the treatment of phosphogypsum leachates) dispersed in an inert matrix (i.e., wood chips) to raise the pH of acidic water and consequently decrease the solubility of dissolved contaminants. The proposed treatment achieved the total removal of Al, Fe, Cu, Cd and rare earth elements and Y (REY). The solubility of the contaminants during the treatment was probably controlled by co-precipitation and/or adsorption processes onto Fe and Al oxyhydroxides-oxyhydroxysulfates. This work contributes to the minimization of the economic and environmental costs of mine water treatment with DAS technology.