What is Ozonated Water?
Ozonated water, sometimes referred to as 'aqueous ozone,' is water that has been infused with ozone gas ($O_3$). This colorless, unstable, and powerful oxidizing agent is composed of three oxygen atoms, which differentiates it from the oxygen we breathe ($O_2$). The primary purpose of introducing ozone into water is to leverage its potent disinfectant properties. When dissolved in water, the unstable $O_3$ molecule readily transfers one of its oxygen atoms to react with and oxidize organic materials, bacteria, viruses, and other contaminants.
The process, known as ozonation, is a well-established water treatment technique used globally in municipal water plants and bottled water facilities. The appeal of ozonation over chemical alternatives like chlorine lies in its ability to purify water without introducing persistent chemical residues. After disinfection, the ozone molecule reverts back to stable, harmless oxygen ($O_2$), leaving behind only purified water and increased oxygen levels. This reversion is quick, with a half-life of only about 15 minutes, which is why it must be generated and used on-site.
The Science Behind Water Ozonation
The generation of ozonated water typically occurs through one of two methods: corona discharge or ultraviolet (UV) light. Both processes mimic natural ozone production (like lightning during a thunderstorm) by using high-energy electrical discharge or UV light to split oxygen molecules ($O_2$) into individual oxygen atoms. These free oxygen atoms then recombine with other $O_2$ molecules to form ozone ($O_3$).
- Corona Discharge: This method uses a high-voltage electrical field to generate ozone. It is highly efficient and common for large-scale industrial and municipal water treatment.
- Ultraviolet (UV) Light: This method uses UV lamps in the 160–240 nm range to produce ozone. While less powerful than corona discharge, it is often used in smaller home ozone water systems.
Once the ozone gas is generated, it is injected into the water. Its powerful oxidizing action rapidly destroys the cell walls of microorganisms and breaks down other contaminants. The byproduct of this oxidation is pure water and oxygen, which is one of the main reasons it is considered an environmentally friendly purification method.
Reported Benefits of Drinking Ozonated Water
Proponents of drinking ozonated water often point to a range of potential health benefits, though many claims require more recent and extensive research for full validation.
- Potent Disinfection: Ozonation is exceptionally effective at neutralizing a broad spectrum of pathogens, including bacteria (like E. coli), viruses, fungi, and parasites (like Giardia and Cryptosporidium) that are sometimes resistant to chlorine.
- Increased Oxygen Levels: Some believe the increased oxygen levels in ozonated water can aid bodily functions, improve energy, and support the immune system.
- Antioxidant Properties: Although ozone itself is an oxidant, some studies suggest that exposure can trigger the body's own antioxidant responses, helping to clear free radicals.
- Detoxification: Ozonated water is believed by some to aid in flushing toxins and waste products from the body.
- Improved Oral Health: In dentistry, ozonated water is used for its antimicrobial properties to reduce oral bacteria and promote healing. Some studies have explored its use as a mouth rinse to combat bacteria linked to tooth decay.
- Better Taste and Odor: The oxidation process can remove taste and odor-causing compounds, resulting in cleaner-tasting water.
Potential Risks and Disadvantages
Despite the promising benefits, it is crucial to understand the risks associated with ozonated water, especially for home use.
- Inhalation of Ozone Gas: When improperly handled, ozone gas can be toxic if inhaled, causing respiratory irritation, coughing, and shortness of breath. Safe handling by qualified professionals is key to preventing exposure.
- Carcinogenic Byproduct Formation: If the water being ozonated contains high levels of bromide ions, the process can produce bromate, a known carcinogen. Professional water treatment facilities carefully monitor and manage these conditions, but this is a significant risk for unregulated home use.
- Corrosion: The highly reactive nature of ozone can cause corrosion to pipes and fixtures, especially if not made of ozone-resistant materials like stainless steel.
- No Residual Disinfection: Unlike chlorine, which remains in the water to provide continued disinfection, ozone breaks down quickly. This means ozonated water has no residual effect to prevent microbial regrowth during storage or distribution.
- Cost and Complexity: Home ozonation systems can be expensive to purchase, operate, and maintain. Proper knowledge is required to avoid potential hazards.
Comparison of Water Disinfection Methods
| Feature | Ozonation | Chlorination | UV Disinfection |
|---|---|---|---|
| Effectiveness | Highly effective against a wide range of pathogens, including Giardia and Cryptosporidium. | Effective, but less so against certain parasites and viruses. | Destroys microorganisms, but requires clear water and does not remove chemicals. |
| Byproducts | No harmful chemical residues left behind, but can form bromates in bromide-rich water. | Creates harmful disinfection byproducts (DBPs) like trihalomethanes (THMs). | No harmful byproducts formed. |
| Taste & Odor | Often improves taste and odor by oxidizing related compounds. | Can leave a distinct, unpleasant taste and odor. | No impact on taste or odor. |
| Residual Protection | No residual effect; must be used immediately or re-disinfected. | Provides residual protection throughout distribution systems. | No residual effect. |
| Cost | High initial equipment and operational cost. | Relatively inexpensive. | Medium initial cost; low operating cost. |
| Environmental Impact | Eco-friendly; reverts to oxygen. | Less environmentally friendly due to chemical byproducts. | Eco-friendly; uses UV light. |
Conclusion
Drinking ozonated water, particularly from professionally treated municipal sources, is widely considered safe and even beneficial due to its powerful purification properties and lack of chemical residues. In fact, thousands of municipalities worldwide use ozonation to treat public drinking water supplies. However, the health benefits touted by some proponents—such as cancer prevention or significant immune boosting—are not yet sufficiently supported by recent, comprehensive human studies and should be approached with caution.
For personal use with home ozonators, extreme care is necessary. The potential for toxic gas inhalation and the formation of carcinogenic byproducts like bromate (if the source water has high bromide levels) are significant risks that are not present in professionally managed systems. While home ozonators can be effective for disinfection tasks like cleaning produce, a thorough understanding of your water source and the equipment is essential before considering it for drinking water. As with any health-related product, consulting a healthcare professional is always recommended. For more comprehensive water quality information, visit the World Health Organization website.
