Ozone is one of the strongestoxidants that can be implied for the removal of pollutants from drinking water.Due to the high oxidation and disinfection efficiency, ozone has been used indrinking water treatment for many years. Ozone has been applied for the removalof inorganic species from water. Pre-oxidation using ozone followed by thefiltration or coagulation-flocculation-decantation have been used for theelimination of inorganic species from water.
The metallic ions form insolublespecies upon oxidation and can easily removed 46. Another advantage of ozoneis its ability to remove ammonia from water 46. Another important applicationof ozone is its ability to kill microorganisms from water. It has been impliedfor the inactivation of bacteria, viruses and the control of algal growth. Itcan inactivate microorganisms such as protozoa, E. coli, Bacillus sublilisspores, Rotavirus and Giardia lamblia cysts 47. Ozone can penetrate throughthe cell membrane of Escherichia coli and react with the cytoplasmicsubstances.
In addition, the degradation of nucleic acids, is being one of theimportant factors responsible for cell killing 46. The ozone can inactive theviruses by attacking their protein coat or direct damage of nucleic acids. Ithas been reported that ozone can attack both the protein coat and ribonucleicacids of tobacco mosaic virus 46.Ozone can remove effectivelyorganic pollutants from drinking waters. However, it reacts slowly with someorganic compounds such as organic acids, methyl tertiary butyl ethers (MTBE)and chlorinated organic compounds. 44.
Despite the many advantages of ozonetreatment as discussed above, the major disadvantage of ozone is the formationof toxic by-products (e.g. organic acids). Therefore, it is important to implyadvanced oxidation processes. Many advanced oxidation processes have beendeveloped which have high efficienciently of mineralize organic compounds, whencompared with ozonation alone, for example catalytic ozonation, O3/UV, O3/H2O2and UV/ H2O2 48-51.