Adsorptive Iron Removal from Groundwater

This work covers topics including: the adsorption of iron (II) onto filter media and iron hydroxides; the effect of water quality on iron (II) adsorption; the characterization of coated sand from iron removal plants; and the development of iron oxide coating on filter media.

A pilot study conducted at the Gilze water treatment plant of Water Supply North West Brabant demonstrated that adsorptive filtration has several potential advantages over floc filtration, namely: longer filter runs due to slower head loss development; better filtrate quality; shorter ripening time; and less backwash water use. In existing groundwater treatment plants, the high iron (II) adsorption capacity of the iron oxide coated filter media makes it potentially possible to switch the governing mode of operation from floc filtration to adsorptive filtration. To achieve this two options can be considered: iron (II) adsorption under anoxic conditions followed by oxidation with oxygen-rich water; and adsorption of iron (II) in the presence of oxygen and simultaneous oxidation. The first option might be attractive specifically when two filtration steps are available.