[Studies on virus inactivation by chlorine during water disinfection (author's transl)]

The studies described indicate a potential for water-borne transmission of viral diseases and the problems involved in virus inactivation by means of water chlorination. In contrast to the amount of free chlorine, the value of the oxidation-reduction potential (ORP) was found to be a criterion of virus inactivation. For virus inactivation, higher ORP values and longer periods of contact than for the killing of bacteria, respectively, were found to be necessary. To ensure the inactivation of poliovirus in water contaminated with organic substances, an ORP of + 780 mV (0.3-0.6 mg/l free chlorine) should be maintained for 15-30 min. Adenovirus has shown an almost identical resistance to inactivation. Possibilities for utilizing the mechanism of virus inactivation by the action of chemical disinfectants are discussed.