What is Ozone Water Treatment and How Does It Work?

Posted by
John Woodard on March 19, 2021
Ozone is a naturally occurring gas in earth’s atmosphere and is one of nature’s most powerful oxidizers. In the upper atmosphere, ozone filters the sun’s ultraviolet light and protects earth from harmful radiation, but here on the surface, ozone plays a role in ensuring clean drinking water through ozone water treatment. Ozone water treatment is versatile and can be employed both commercially and in your home. Below you will learn about ozone water treatment, how it works, and whether an ozone water treatment system is right for you.

What is ozone water treatment?

Ozone water treatment is a water treatment method that reduces contaminants through ozone’s oxidative strength. Ozone is an oxidant, which means it reacts with other substances and accepts their electrons. For example, when iron is oxidized, it becomes rust. Ozone water treatment begins with the creation of ozone in an ozone generator. Then, ozone is injected into water, and immediately starts oxidizing and eliminating contaminants, such as bacteria, viruses, and metals.

Ozone oxidizes organic material in the membranes of bacteria, viruses, and parasites. This weakens, ruptures, and kills their cells, eliminating the troublesome contaminants. Ozone also oxidizes iron, manganese, and copper into solid particles that can be easily filtered from water by mechanical filtration or certain activated carbon filters. Through oxidation, ozone water treatment systems can even rid water of turbidity and bad tastes and odors caused by chlorine.

Learn More: Activated Carbon Filters 101

How does ozone water treatment work?

Ozone water treatment works by dissolving ozone into water and through the ensuing oxidation of bacteria and other waterborne pathogens. To better understand the process, it is best to first understand how ozone is created. Ozone is born out of oxygen. An oxygen molecule contains two oxygen atoms (O2), while an ozone molecule contains three oxygen atoms (O3). When electricity or ultraviolet light stream through air, their energy splits oxygen molecules into two oxygen atoms. The loose oxygen atoms then recombine with ordinary oxygen molecules to form ozone. In the upper atmosphere, sunlight interacts with oxygen to produce earth’s protective ozone layer. While closer to the surface, ozone is created when lightning strikes and electricity cuts through oxygen rich air. Both processes are mimicked in ultraviolet and electrical ozone generators, which make ozone water treatment possible. Ozone can also be produced by electrolytic and chemical reactions, but UV and electrical ozone generators are the most common for water treatment.

Electrical ozone generators:

Electrical ozone generators produce ozone through corona discharge, which mirrors the way ozone is created during a thunderstorm. Instead of lightning, a high voltage electrical discharge is passed through oxygen inside a glass, ceramic, or steel chamber. This facilitates the breakdown of molecular oxygen into atomic oxygen and allows for the formation of ozone. The ozone is then either bubbled into water or vacuumed in through a venturi tube and the oxidation process begins immediately.

Ultraviolet light ozone generators:

Ultraviolet light in the 160-240 nanometer (nm) range can create ozone from oxygen. Similar to the corona discharge process, UV light disrupts oxygen molecules and splits them into two oxygen atoms. The free atoms then combine with whole oxygen molecules to form ozone. In a UV ozone generator, ozone is produced as oxygen is passed between the lamp and the quartz sleeve of a UV light. The ozone is then drawn into water using a venturi and the water treatment process begins. However, UV ozone generators are not as powerful as electrical ozone generators and produce ozone at lower concentrations.

What do ozone water treatment systems remove from water?

  • Bacteria
  • Viruses
  • Parasites, such as giardia and cryptosporidium
  • Hydrogen sulfide
  • Bad tastes and odors
  • Turbidity
  • Iron, manganese, and copper (when combined with another filtration method)


Bacteria in Water

Benefits of ozone water treatment systems

1.      Effectiveness

Ozone is a strong oxidizer that instantly neutralizes biological matter, such as bacteria, viruses, and parasites, and has stronger disinfectant properties than chlorine. Ozone’s oxidative strength also helps eliminate otherwise stubborn metals from water. Ozone is effective over a wide range of pH, so even if you have acidic water, the effectiveness of ozone water treatment will not be hampered.

Learn More: What is Acidic Water and How Do You Treat It? 

2.      Chemical free

Ozone water treatment does not add chemicals to water. No pollutants are created in the ozone water treatment process, and any wastewater produced is safe to enter waterways and drains.

3.      Tried-and-true technology

Ozone water treatment is a tried-and-true technology that has been used to treat municipal water supplies since the early 1900s. A water treatment plant in Nice, France began using ozone water treatment commercially in 1906, and today it is used at more than 2,000 installations worldwide.

4.      Speed

Ozone water treatment is incredibly fast. Most water treatment systems require extended contact time to eliminate or reduce contaminants, but ozone works in mere seconds.

Disadvantages of ozone water treatment systems

1.      Cost

Ozone water treatment is expensive compared to more well-known water treatment methods, such as chlorination. It has high equipment and operational costs, and it may be difficult to find a professional who is proficient in ozone water treatment. Home ozone water treatment systems cost between a few hundred and a few thousand dollars. Although, for municipalities ozone water treatment could be cost effective overtime, because it offsets the chemical costs required for chlorination.

2.      Difficult to transport

Ozone has a short half-life once dissolved in water, as its natural reaction is to turn back into oxygen. Therefore, it is difficult to store and transport and must be generated onsite for immediate use.

3.      Potential corrosion and toxicity

Ozone is a toxic gas, so if an ozone generator leaks, it could create a hazard in your home. Common side effects of ozone exposure include headache and irritation of the eyes and throat. Also, because ozone is a strong oxidizer, it can corrode pipes and fixtures if they are not made of ozone resistant materials, such as stainless steel or Teflon.

What is ozone water treatment used for?

Ozone water treatment is used in commercial, industrial, and municipal water treatment systems, as well as in home systems. Major beverage companies rely on ozone water treatment technology and it is often used to disinfect bottled water. Ozone is also employed by cities to treat and disinfect municipal water supplies. Lastly, an ozone water treatment system can be purchased for your home. Their disinfectant properties are appealing to well owners who are concerned about the presence of bacteria and viruses in their water and may be used by people on a city water supply as an extra line of defense against contaminants. Also, ozone water treatment is an effective method to sanitize ice machines. For example, the Oxidice Ozone Sanitation System sanitizes the air, water, and surfaces within an ice machine, producing clean, odor-free ice.

Learn More: How to Remove Bacteria from Drinking Water 

Ozone water treatment vs. chlorination

Chlorination has been the traditional chemical process for water purification for decades, but ozone water treatment is gaining popularity. Ozone and chlorine are often compared because both have strong disinfectant properties, but they differ in speed, chemical presence, and overall effectiveness. Ozone water treatment systems disinfect water about three times faster than chlorination and require a shorter contact time with water to be effective. In an ozone water treatment system, disinfection occurs at the point of contact between ozone and water. Whereas chlorine will remain in water and continue the disinfection process for some time. This is why you may occasionally smell chlorine in your tap water. The residual amount is not harmful to consume, but has an unpleasant, chemical smell. When using an ozone water treatment system, there is no ozone left in the water when it is ready to drink.

Currently, chlorination is less expensive than ozone water treatment, but with advances in technology ozone water treatment is becoming more affordable and many municipalities are considering the move to ozone. Plus, with ozone there is no concern of chemical by-products, such as chloroforms and halomethanes, as there is when using chlorine. Lastly, certain parasites, such as cryptosporidium and giardia, are resistant to chlorine but not to ozone and can be swiftly eliminated in an ozone water treatment system.

Is ozonated water safe to drink?

Yes, ozonated water is safe to drink. Oxidation is a natural process that eliminates the need for chemicals. Ozone water treatment systems produce zero chemical by-products and yield only purified water. However, it is recommended to wait at least thirty minutes after treatment to drink the water, so any residual ozone has time to convert back into oxygen.

Do you need an ozone water treatment system?

You may need an ozone water treatment system if you are on well water and are concerned with nuisance minerals, such as iron and manganese, or the presence of bacteria, viruses, or parasites. If you are on municipal water, your water is already disinfected before it reaches your home, but an ozone water treatment system would provide extra protection in the event of a natural disaster or if you are put on a boil water advisory.

Learn More: Boil Water Advisory Procedures


If you have any further questions about ozone water treatment or how to improve your water quality, please don’t hesitate to contact us.

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