Ozone Water Purification: Pros and Cons

Much like other less common forms of treating water, ozone water purification has distinct advantages over chemical processes like chlorination. That said, it is at a disadvantage for other reasons as well. Water purification, the process of removing contaminants from water, occurs with many different methods, each of which has potential side effects. While chlorination is the most common means of treating raw water, other processes like ozone disinfection and ultraviolet radiation are used in some places in the world. Ozone disinfection, for instance, has been a known and used technology for well over 100 years and is commonly used in Europe.

How Ozone Disinfection Works

Ozone or Oâ, being an unstable molecule, releases from its bond what is called a free radical. In this case it is one oxygen atom. This single atom is very toxic to the majority of microorganisms found in untreated water. On site at the water disinfection plant, oxygen is passed through ultraviolet light. This process creates ozone which is then added to the water in the form of bubbles. Once immersed in the water, the free radical oxygen atom is released from the molecule and disinfects the water by bonding with the other particles in the water, in effect transforming them into something else. This is called oxidation and works to destroy bacteria, parasites and other harmful pathogens.

Ozone Water Purification Advantages

Much like ultraviolet water purification, using ozone as a disinfectant does not produce the same number of byproducts as a process like chlorination. It is the production of chemical byproducts that puts treated water at risk. The risks associated with chlorination are mitigated by other additions to the water, rendering that process safe for consumption. However, ozone disinfection avoids that step. Another advantage is similar to ultraviolet water purification in that the use of ozone does not cause the treated water to have an unpleasant, chemical taste.


There are, however, disadvantages to ozone disinfection. Although the production of chemical byproducts are fewer with ozone, it has been shown to produce a small amount of bromate which is suspected to be a carcinogen. Treated water should have little if any bromine. Secondly, like ultraviolet water purification, ozone disinfection provides no residual effect. Thus, if any harmful microorganisms survive the oxidation, there is the risk that they will survive the treatment process. Ozone treatment must then be a continual process to ensure that all organic molecules in the water are bonded with the free radical oxygen atom and neutralized.

One of the best arguments for using ozone disinfection of water is that it is a process that occurs naturally. Oxidation of the air occurs during a lightning storm and by the interaction of ultraviolet sunlight and the surrounding atmosphere. When used to purify water, it is basically an imitation of a natural process that has been successfully harnessed by technology. Measures must be taken, of course, to ensure the process creates safe drinking water, but by oxidizing harmful bacteria, viruses and other pathogens and transforming them into something harmless, the use of toxic chemical additives is avoided.