What are the three forms of chlorine available for use in water treatment?

Chlorine is a critical disinfectant used in water treatment, and it is available in several forms, each with distinct properties and applications. The correct answer identifies chlorine gas, sodium hypochlorite, and calcium hypochlorite as the three prevalent forms.

Chlorine gas is the most basic and powerful form, typically used for large-scale water treatment plants. It is highly effective in killing bacteria and viruses, making it a first choice for disinfection processes.

Sodium hypochlorite, often found in liquid form as household bleach, is another widely used chlorine compound that is more manageable for smaller systems or point-of-use applications. It also serves as a powerful disinfectant with a lower risk of gas leaks compared to chlorine gas.

Calcium hypochlorite is available as a solid, making it convenient for storage and transport. It is often used in swimming pools and water treatment facilities due to its stability and effectiveness as a disinfectant.

The combination of these three forms provides flexibility in application, depending on the specific needs and scale of the water treatment process. As such, understanding the unique characteristics of each form is essential for water quality analysts working to ensure safe and potable water.