Chlorine is preferred over bisulfite for HO quenching following UV-AOP drinking water treatment.

Drinking water treatment using UV/HO advanced oxidation typically results in residual HO that requires quenching to minimize its interference with downstream processes. Chemical quenching using chlorine or bisulfite are options, but there is some uncertainty in the literature about the kinetics of the bisulfite reaction, with some reports quoting the reaction as fast, and others as slow. Part of the contradictory information may be due to interference in HO analysis by bisulfite.