Ozone treatment combined with a maintenance disinfectant such as chlorine or bromine is an easy and effective method for disinfecting swimming pools. The chemistry of a swimming pool in practice, however, can be quite complicated, as it is with all pool treatments. The use of ozone in swimming pool disinfection provide many benefits over chemical based disinfection methods. In addition to partially oxidizing organic contaminants, ozone also disinfects and ensures optimal clarity of water through flocculation. Ozonation can achieve water quality unattainable with other pool treatments when it is designed and operated correctly. This is why ozone swimming pool sterilization is undoubtedly the best.
While all modern swimming pool treatments are effective, some treatments have significant advantages over others due to the diversity of pool design, hydraulics, and usage. Leisure activities have taken the focus away from traditional lane swimming or training pools in recent years, which has led to a change in the design criteria for commercial swimming pools.
Oxidizing Potentials of Different Reagents
|Oxidizing Reagent||Oxidizing Potential (V)|
|Hydroxyl free radicals||2.80|
The table above shows that hydroxyl radicals have a much higher oxidation potential than ozone molecules themselves. Consequently, these compounds help with chemical oxidation, but because they have a very short half-life (microseconds), they are not much effect in the disinfection process. In this situation, ozone swimming pool sterilization is the perfect solution because of its proven effectiveness.
Ozone Concentration for Sterilizing a Pool
The chemical symbol for ozone is O3. This is because the ozone molecule contains three oxygen atoms and is for this reason referred to as the triatomic state of oxygen. Oxygen in its molecular form is represented by the chemical symbol O2. Since ozone is primarily converted back to oxygen following oxidation, it is an environmentally friendly oxidant. Certainly, ozonation does not involve such simplistic chemistry, but in comparison to other oxidants, such as chlorine, ozonation produces fewer undesirable byproducts.
Odorless and unstable, ozone is characterized by a pungent odor. As it is formed by photochemistry in the stratosphere of the earth, it is very low in concentration at ground level. At normal temperatures, ozone is a blue gas. Ozone generators using corona discharge can readily demonstrate this phenomenon.
Ozone has an odor threshold of 0.01 parts per million. A concentration of more than 5 ppm of ozone will produce a strong acrid smell and a faint blue color. A low concentration of ozone maintains a relatively long half-life of 36 minutes in the air. When an ozone swimming pool sterilization is used, water is a medium for a variety of chemical reactions that can occur once ozone is added.
Ozone is highly dependent upon the source of water and the type of oxidizable contaminants in the solution in order to remain stable or depleted.
Ozone has an oxidation potential of 2.07 Volts in comparison with chlorine at 1.36V and bromine at 1.09V (refer to table above). For swimming pool treatment, dissolved ozone reacts with contaminants either directly, as O3 molecules, or indirectly, as free radicals. At low pH, the direct reaction dominates, but above pH 7 the latter reaction dominates.
Effectiveness of Ozone Vs. Other Disinfectants
Even though ozone swimming pool sterilization has been proven to be the best choice. Most pools and spas use chlorine or bromine to treat their waters. To achieve the desired free halogen residual, the halogen compounds are added until the desired amount is reached. It is important for a disinfectant that oxidizes organic and some inorganic contaminants to serve two functions. One is to oxidize contaminants, and the other is to disinfect them. Swimming pools are primarily halogenated with chlorine, but indoor heated pools produce unpleasant chlorine smell, chloro-organic byproducts that cause skin and eye irritation, and volatile chemicals that cause significant corrosion.
When it comes to disinfectants, chlorine is an excellent oxidizer as well as an effective disinfectant. The chlorine, however, forms chloramines when it reacts with nitrogen-based compounds. In contrast, bromine, either free or combined, has weak oxidizing capabilities but has excellent disinfecting abilities. Pool water must maintain high bromine residuals due to its lower oxidizing capacity. Chlorine and bromine are 97 and 52 in terms of their molecular weights respectively. When residuals are to be determined as bromine, the need for a test kit multiplier becomes obvious. A given quantitative residual makes the DPD test half as dark when bromine is added.
When looking for alternative oxidation options, ozone was the obvious choice. A powerful oxidant available commercially is ozone, but it is an unstable gas, so it has to be generated and used at the application site. Both chlorine and bromine are far less effective oxidants and disinfectants than ozone. Therefore, it is obvious that commercial pools must use ozone swimming pool sterilization over other solutions.