What is the most commonly used disinfectant in water treatment?

Chlorine is the most commonly used disinfectant in water treatment due to its effectiveness in killing a wide range of pathogens, including bacteria, viruses, and protozoa. It has been utilized for over a century because of its ability to quickly and efficiently disinfect water supplies, making it a staple in municipal water treatment processes.

Additionally, chlorine is relatively inexpensive and easy to apply in various forms, such as gas, liquid, or solid. Once added to water, chlorine reacts with organic and inorganic substances, effectively inactivating harmful microorganisms. It also provides a residual effect; meaning that it continues to disinfect as water travels through the distribution system, helping to maintain water safety until it reaches consumers.

While other disinfectants like bromine, ozone, and chloramine are used in certain situations, they are less common than chlorine for general water treatment practices. Bromine is more frequently applied in specific applications like swimming pools, ozone is effective but can be more complex and expensive to generate and use, and chloramine is often used as a secondary disinfectant due to its stability but does not possess the broad-spectrum effectiveness and immediate action of chlorine. Thus, chlorine remains the primary choice for water disinfection in most conventional systems.