Ozonation is different from UV treatment and is another method to disinfect and even sterilize an item/material (water). Free or nascent oxygen is biocidal (that is why hydrogen peroxide was used for a long period of time for wound cleansing- although it is really not that great and can cause tissue damage).

There are many means to sterilize a product/material; steam under pressure, long exposure to dry heat, ethylene oxide, paraformaldahyde, peracidic acid, UV radiation are but a few. Each has advantages and disadvantages and appropriate uses. In the last 5-10 years, the industry has developed peroxide autoclaves for sterilizing certain items; similar technology is used for the ozonation of water.

Hope this helps and is not too confusing.

Pete