Which chemical is commonly used for disinfection in water treatment?

Chlorine is widely recognized as a primary disinfectant in water treatment processes due to its effectiveness in inactivating bacteria, viruses, and other pathogens. It can also provide a residual effect, meaning that it continues to kill pathogens that may enter the water supply after treatment. This is critical as it ensures the safety of drinking water throughout the distribution system.

The use of chlorine in water treatment is fortified by its cost-effectiveness and ease of application, making it a staple in both municipal and industrial water treatment facilities. Chlorine can react with organic matter in water to form by-products; however, modern treatment methods aim to minimize these occurrences while still harnessing chlorine's powerful disinfection capabilities.

In contrast, the other chemicals mentioned serve different purposes in water treatment. Sodium hydroxide is primarily used for pH adjustment and corrosion control, hydrochloric acid also serves to adjust pH levels, and calcium carbonate is typically used to stabilize water by reducing its acidity and preventing corrosion, rather than for disinfection.