Proceedings

Manganese removal in potable water treatment is generally understood to occur either by the
adsorption of soluble manganese II onto filter media, or oxidation to insoluble manganese IV, or by
a combination of both. In practice removal is achieved by filtration through a variety of media, but
nearly always at pH’s >8.

A key objective for the water industry would be to achieve manganese removal at neutral pH within
single stage conventional filtration. This would promote simplicity and improve the sustainability of
the overall treatment process.

Most previous work has focused on filtration media that incorporates manganese in different forms.
Recent reports indicate that removal can also occur with iron based media. This report details
current plant trials with both manganese and ferric oxide related media. Laboratory studies also
indicate that the hydroxides and higher oxides of iron may be implicated in the mechanism of
manganese removal at neutral pH.

KEY WORDS: Water treatment, manganese removal, manganese dioxide, ferric oxide, oxygen uptake