Interestingly, the inactivation of MS-2 by ozone was
very successful, as indicated in Fig. 11. For a transferred
ozone dose of approximately 17 mg/L, counts had
decreased by over 3-logs. Hence it could be expected
that, notwithstanding the high ozone demand of the
wastewater, ozone would be an effective disinfectant for
viruses in this wastewater. This would suggest that the
inactivation mechanism of the bacteriophage was much
different to that of the bacteria, as it had to be almost
instantaneous. The tailing effect is likely an artifact of
the MS-2 enumeration procedure, since MS-2 numbers
cannot be accurately measured below 1 PFU/mL, but it
could also be due to clustering.