Stability of As- and Mn-sludge after neutral mine water treatment using Fe(VI) vs electrocoagulation.

The electrocoagulation (ECG) and ferrate (Fe(VI))-based processes are increasingly acknowledged as efficient for the simultaneous removal of As and Mn from synthetic and real mine effluents. Prior to design of full-scale applications, more information on the physicochemical, mineralogical, and environmental characterization of the produced sludge is required. The main objective of this study was to characterize and evaluate the leaching potential of problematic elements in As- and Mn-rich sludge produced during ECG or Fe(VI) treatment of circumneutral surrogate mine water.