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How does ozone disinfect drinking water?

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Diagram of a water treatment plant showing the process from water inlet through mixing, coagulation, flocculation, settling, filtering, chemical treatment with chlorine, storage, and high-lift pumping to the distribution system. — water purification Water from inlets located in the water supply, such as a lake, is sent to be mixed, coagulated, and flocculated and is then sent to the waterworks for purification by filtering and chemical treatment. After being treated, the water is pumped into water mains for storage or distribution.

Ozone disinfects drinking water by acting as a powerful oxidizing agent that destroys pathogenic bacteria and other microorganisms. This process is essential for preventing the spread of waterborne diseases.12

Because ozone is highly unstable, it cannot be stored and must be generated on-site by passing an electric discharge through a current of oxygen or dry air. Once applied to clarified water, it effectively sterilizes the supply and helps remove objectionable odors and flavors.321

Unlike chlorination, ozone does not cause taste or odor problems, but it also leaves no residual concentration in the water. This lack of a residual makes it difficult to monitor the continued effectiveness of the disinfection as the water travels through a distribution system. Consequently, while ozone is a highly effective germicide, the process is generally more expensive than traditional chlorination methods.3