In this stage three more water supplies are considering the implementation of ozonation.

Upgrading with ozonation and advanced oxidation is in the most advanced stage.

The main objectives of the retrofit treatment are increasing disinfection capacity by ozone against pathogenic organisms,especially viruses and Giardia cysts

removal of taste and odour,mutagenicity and pesticides by O3/GAC.Optional advanced oxidation may be applied

removal of AOC by GAC-filtration,reduction of colony counts and barrier against Coliform regrowth by UV-disinfection

avoidance of chlorine for main and post disinfection in order to prevent THM and AOX-formation

restriction of bromate formation.

Water supply companies still consider the application of ozonation and GAC-filtration an interesting option for combined disinfection and organic contaminant control.They expect bromate formation can be restricted to values lower than the expected standard of 10μg/l or 5μg/l.

Ozone treatment(Japanese)