Which of the following components is essential for effective chlorination?

For effective chlorination, the presence of free chlorine is essential. Free chlorine refers to the amount of chlorinated disinfectant that is available to react with pathogens and organic matter in water. It is crucial because it ensures that chlorine is actively working to disinfect and kill bacteria, viruses, and other harmful microorganisms present in the water supply.

When free chlorine is utilized during the chlorination process, it helps maintain a residual concentration in the water distribution system, which is important for continuous protection against recontamination. This residual chlorine acts as a safeguard, ensuring that untreated water does not compromise the safety of the treated water during transport and storage.

Other factors like temperature and pH can influence the efficacy of chlorination, but they do not replace the need for free chlorine itself, which is the primary active disinfectant in chlorinated water. Organic matter, on the other hand, can consume chlorine and reduce the effectiveness of the chlorination process, making it all the more crucial to ensure a sufficient level of free chlorine to achieve effective disinfection.