Abstract

Chlorine is one of the most widely used disinfectants in drinking water treatment processes due to its high efficacy, low cost, and ease of application. This study aims to review the disinfection efficiency of chlorine against various pathogenic microorganisms, including bacteria, viruses, protozoa, and intestinal parasites. The results showed that chlorine is effective against most types of bacteria and viruses when appropriate doses and sufficient contact times are used; however, its effectiveness is limited against certain protozoa such as Giardia lamblia and Cryptosporidium parvum, which require higher concentrations and longer contact times to achieve high inactivation rates. The study also indicated that chlorine efficacy increases with higher temperatures and lower pH levels, while it decreases at low temperatures or in the presence of organic matter. The study recommends integrating other processes such as filtration and coagulation before chlorination to achieve comprehensive removal of microorganisms and ensure the quality of the produced water.