The four common disinfectants listed include which combination?

• A. Chlorine, Ultraviolet, Ozone, Peracetic Acid
• B. Chlorine, Ozone, Ultraviolet
• C. Ultraviolet, Ozone, Peracetic Acid
• D. Chlorine, Peracetic Acid

Answer: (A)

Disinfection in wastewater treatment relies on several common methods, and recognizing the major options helps you see why this four-part mix is correct. The four disinfectants often listed are chlorine, ultraviolet light, ozone, and peracetic acid. Chlorine is a longtime staple because it provides reliable disinfection and leaves a residual that protects downstream steps. Ultraviolet light disinfects without adding chemicals, which is useful when you don’t want residuals but you need good clarity and clear water for proper exposure. Ozone is a powerful oxidant that inactivates microorganisms quickly, though it requires on-site generation and more complex control. Peracetic acid adds another chemical option with a different performance and byproduct profile, useful in plants seeking alternatives to chlorine or ozone. The other choices miss one or more of these four, so they don’t represent the full set commonly referenced in practice.