Summary

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.