Compared to chlorine (Cl2), ozone disinfects at a faster rate.

• A. Slower
• B. Faster
• C. Not a disinfectant
• D. About the same

Answer: (B)

Ozone acts as a very fast, strong oxidant, so it inactivates microorganisms quickly by attacking their cellular components. This rapid action means you can achieve significant disinfection with a much shorter contact time than chlorine, especially under typical water quality conditions. Chlorine works, but its reactions proceed more slowly and can be hindered by substances in the water like organic matter or ammonia, which consume the disinfectant and extend the needed contact time. Additionally, ozone breaks down quickly and doesn’t leave a lasting residual like chlorine does, which is another reason its disinfection occurs faster but with little downstream residual. Taken together, ozone disinfects at a faster rate than chlorine.