Chlorination and ozonation are effective techniques for purifying drinking water by disinfecting it. Through these methods, contaminants in water can be eliminated by causing a chemical reaction that transforms dissolved contaminants into insoluble ones.


The act of adding chlorine or chlorine-containing compounds to water for the purpose of disinfection is known as chlorination. This approach is effective in eradicating bacteria and other microorganisms present in tap water as chlorine is lethal to them. Additionally, chlorination plays a crucial role in averting water-borne illnesses like cholera and typhoid.


As a disinfectant, chlorine is incredibly effective. It can be introduced into public water sources to eliminate pathogens that typically thrive in water reservoirs. Chlorine is produced by electrolyzing salt and generally takes on a gaseous state at room temperature, although it can be liquefied and utilized for disinfection purposes.

Being a potent oxidant, chlorine eliminates bacteria by oxidizing organic molecules within microorganisms. Chlorine and its hydrolysis product, hypochlorous acid, are charged chemical compounds that can effortlessly permeate the negatively charged surfaces of pathogens. These substances can degrade lipid components of the cell wall and react with intracellular enzymes, rendering the pathogen inactive. As a result, the microorganisms either perish or lose their capacity for replication.


Ozonation is an effective technique for disinfecting drinking water that involves adding ozone. It can be utilized for treating drinking water to eliminate effluents and break down organic and inorganic pollutants in wastewater. Nonetheless, ozone is an unstable gas that rapidly decomposes into oxygen, resulting in no residual disinfectant effect or byproduct formation during ozonation.

An ozonation system typically comprises an ozone generator and a reactor, which allows ozone to be introduced into the water being treated via bubbling. Ozone is a robust oxidizing agent that directly targets the surface of microorganisms, disintegrating their cell walls. Consequently, the microorganisms lose their cytoplasm and become inactive.


Differences between Chlorination and Ozonation

Two methods of purifying drinking water are chlorination and ozonation. The fundamental distinction between these techniques is that chlorination employs chlorine for disinfection, while ozonation employs ozone. Furthermore, chlorination oxidizes organic molecules in pathogens, whereas ozonation entails direct ozone attack on the surface of microorganisms.

The following are the summary of the differences between chlorination and ozonation.

How They are Defined

Chlorination: Chlorination refers to the introduction of chlorine or chlorine-containing compounds into water for the purpose of disinfection.

Ozonation: Ozonation is a water purification method that utilizes ozone to disinfect and purify drinking water.

What They Use

Chlorination: Chlorine in its liquid state.

Ozonation: Ozone

How They Work

Chlorination: The process of oxidizing organic molecules within pathogens.

Ozonation: The process of directly targeting and attacking the surface of microorganisms.

To Sum Up

Chlorination and ozonation are two methods for purifying drinking water. The primary distinction between the two is that chlorination involves disinfecting water with chlorine, while ozonation involves disinfecting water with ozone. To learn more about the use ozone for water treatment and other applications, please go to our What’s Ozone and Ozone Applications.