Test Results for a 20-Liter Clear Water Sample

Performance Graph

Graphical test results include data for:

Ozone - blue diamonds, reported in mg/liter. Ozone concentrations were directly measured in the treated water using chemical analysis.

Ozone Outgassing - red squares, reported in ppm. Outgassing was directly measured using the instrument's build-in UV ozone meter.

Sterilization times - reported in minutes. Sterilization time was calculated using the measured Ozone concentration in the water and published C-T values for the pathogens listed. For example, had the water sample contained E. coli contamination, that bacteria would have been eliminated after a minute and a half of machine operation. Similarly Poliovirus could have been eliminated in two and a half minutes, Giardia lamblia in three minutes and Cryptosporidium parvum in nineteen minutes. It is important to note that Chlorine sterilization is significantly less effective on the latter two pathogens. One common definition of "sterile water" is sustaining an ozone concentration of 0.4 mg/l for a period of 4 minutes. This point is reached at the eight minute time mark in this sample, but as can been seen from the above plotted data, actual potability or sterility depends on the properties of the input water and the pathogens present in it.

References for C-T values

E. Coli, Poliovirus and Giardia: G.B. Wickramanayake, A.J. Rubin and O.J. Sproul, "Inactivation of Giardia lamblia Cysts with Ozone" Applied and Environmental Microbiology, Vol. 48 No. 3 pp. 671-672 (September 1984).

Cryptosporidium: M. Cho and J Yoon, "Quantitative Evaluation and Application of Cryptosporidium parvum Inactiviation with Ozone Treatment" Water Science and Technology Vol. 55 No. 1-2 pp. 241-250 (2007).