Vol 33 No 4 Text - International Ozone Association

Ozone News Volume 33, No. 4
Table I. Treated water quality in each treatment process
suspended matters but also ova or larva of organisms.
As a result, the final treatment water can provide a
better water quality than that of Japanese reuse
standards. The outbreak of Chironomid in
reclamation water could be also eliminated.
Treatment efficacy of Cryptosporidium oocysts
The determinations of Cryptosporidium oocysts were
carried three times for the duration of continuous test.
The results are shown in Table II. The determinations
could not prove whether Cryptosporidium oocysts
detected in ozone treatment water were active or
inactive. But it was reported in other research
(Oomura etc,2000) that Cryptosporidium oocysts was
inactivated to approximately 4 log by ozone, as shown
in Table III. Therefore, it is considered that
Cryptosporidium oocysts are inactivated by this ozone
system with C.T. value of more than 13 (mg/L?min.).
Moreover, Cryptosporidium oocysts in MF
membrane treatment water are not detected at all.
This reveals that ozone and MF membrane provide
double hygienic barrier against pathogenic organisms.
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Table II.Removal effect of Cryptosporidium oocysts
Table III. Inactive ratio of C.P.O. to CT value by Ozone