The other problem with ...
Published by Joseph Cotruvo, President at Joseph Cotruvo & Associates, Water , Environment and Public Health
The other problem with chlorine dioxide is that its reduction products are chlorite and chlorate, which are listed in the WHO Guidelines for Drinking Water Quality at 0.7 mg/L for each. It is also difficult to maintain a residual of ClO2.
Some commenters below suggested removing the chlorine dioxide with granular carbon. That would significantly reduce the disinfection efficacy.