Which statement describes the use of high-test calcium hypochlorite in field water treatment?

• A. It is never used in field water treatment.
• B. It is 100% chlorine and used in pools.
• C. It is used only for disinfection of wastewater.
• D. It is a chlorination method containing 65-70% chlorine used for field water treatment.

Answer: (D)

High-test calcium hypochlorite is a solid form of chlorine with a high available chlorine content, typically around 65–70%. In field water treatment, it acts as a chlorination method by releasing hypochlorous acid when dissolved, providing rapid and effective disinfection of water in remote or on-site settings. It’s not 100% chlorine, and it’s not limited to pools or wastewater only; its high chlorine content and solid, portable form make it well-suited for field disinfection where quick dosing and storage stability are important. That combination is why the description of a chlorination method containing 65–70% chlorine used for field water treatment is the best fit.