The level of manganese in the effluent during the dry weather period was higher than that of it influent; this may be due to the anaerobic conditions which occur in the wetland resulting in the decrease in the redox potential transforming manganese from
manganic to manganous compounds at about 225mV [2].
If the groundwater is exposed to an oxidizing agent, the soluble manganese will be converted to its insoluble
manganic form.
Soils are classified as
manganic eutrophic Brown Ferrosol at Kingaroy (Isbell 2002), and self-mulching Black Vertosols at Kingsthorpe (Isbell 2002; Powell et al.
Ferrous iron is readily oxidized by potassium permanganate, as is manganous manganese, with the formation of insoluble ferric hydroxide and
manganic oxide.