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Lookup NU author(s): Dr Karen Johnson
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A major breakthrough has been achieved in passive manganese treatment, since manganese can now be removed at the same time as iron, and efficient manganese removal is feasible even where land availability is limited. The active ingredients of this novel sub-surface flow gravel bed are dolomite and manganese dioxide powder. The catalytic action of these substrates combined with aeration provides the conditions required to overcome the usually slow kinetics of manganese oxidation in the presence of dissolved iron. The small-scale (5 L containers) continuous flow systems were operated for seven months and successfully removed >95% of manganese in this period (raw water Mn concentration ∼20 mg/L). The importance of aeration was successfully demonstrated, particularly when the systems were subjected to environmental stresses such as low (or non-existent) light, low temperatures (down to 4°C) and the presence of dissolved iron in the influent water. Spiking with additional iron (to an initial concentration of 5 mg/L) not only failed to significantly lessen manganese removal rates, but complete removal of the added iron itself was also observed. Since current manganese removal systems fail with iron present at such concentrations in the influent water, these results represent a significant advance in manganese removal options.
Author(s): Johnson KL
Publication type: Article
Publication status: Published
Journal: Land Contamination and Reclamation
ISSN (print): 0967-0513
Publisher: EPP Publications