Efficiency of Ozonation in Decreasing Total Organic Carbon and Total Coliform Bacteria in Isfahan Water Treatment Plant

Document Type : Research Paper


1 Associate Professor, Department of Public Health, Isfahan University of Medical Sciences

2 Graduate Student of Public Health, Isfahan University of Medical Sciences


Ozone, as a powerful oxidant and disinfectant, has found wide applications in water treatment since early 20th century. A concentration level of 0.4mg/L for 5 minutes is considered to be sufficient for conventional disinfection in water treatment. The ozonation-chlorination process, with chlorine as a supplementary disinfectant, has been used since 2003 in phase 1 of Isfahan Water Treatment Plant with an influent capacity of 5m3/s. The object of this study is to determine ozone efficiency in decreasing total organic carbon, total coliform, and fecal coliform in raw water. In this study, 25 samples over the 3 months of study were collected from the influent, after both primary and secondary ozonation stages, and from the effluent from Isfahan Water Treatment Plant. The microbial test and total organic carbon (TOC) were measured. The results showed significant differences (p0.05). The result obtained from this study revealed that the application of ozone as a disinfectant in the water treatment plant in Isfahan is not adequately efficient and that final chlorination may, therefore, be necessary.


1- Tchobanoglous, G., Burton, F.L., and  Stensel, H.D. (2003). "Wastewater engineering: treatment and reuse." 4th  ed. McGraw Hill , 1286- 1295.
2- Gunten, U.V. ( 2003). "Ozonation of drinking water part I, oxidation kinetics and product formation." www.elsevier. com/locate/waters, 1443-1467.
3- Bitton, G. (1999). "Wastewater microbiology." 2nd edition, John Wiley and Sons Inc, 578.
4- Gottschalk, C., Libra .JA., and Saupe, A. ( 2002). "Ozonation of water and wastewater", E. and F.N. Spon Ltd. London, 22-35.
5- Twort, A. C., and Ratnayaka, D. D. ( 2000). "Water supply." 5th ed. IWA , 452.
6- Chapman, D.( 1996). "Water quality assessments." 2nd ed. E. and F.N. Spon.
7- معاونت امور فنی  و تدوین معیارها، (7 137)" راهنمای بهره برداری و نگهداری واحد های تصفیه خانه آب." نشریه 177 سازمان برنامه و بودجه، انتشارات سازمان برنامه و بودجه،(7)، 110-94.
8-APHA, AWWA, WPCF, (1992). "Standard methods for the examination of water and wastewater." 18th ed., APHA, NW.