*2.1.2. Limitations*

Although chlorine gas is used in large-scale water distribution treatment plants and networks as a best method for treating water, still it have various limitations. These limitations might affect the applicability to a point of use (POU) treatment system. Objections against chlorination are because of the esthetic, logistic, and health-related concerns.

Regarding esthetic level, chlorination might be rejected as it imparts bad tastes and odors to the water. The developed countries might teach their people about the good impacts of chlorination; however, less-developed countries lack this ability.

Limitations in using chlorine gas in a household context might include the distribution, procurement/manufacturing, dosing of chlorine, and accurate handling. The health hazards caused by chlorine are not only confined to its volatile nature. A great concern might be the byproducts and incompletely oxidized compounds present in chlorinated water that increases its toxicity. The most notorious byproducts of chlorination are chloro-organics and trihalomethane (THMs). Humic and fulvic acids are present in the water. When chlorine reacts with these acids, trihalomethane are formed. It has been identified in many studies that some of these chloro-organics are mutagens, toxins, or carcinogens. The well-known THM chloroform is an animal carcinogen. Some guidelines have been set by USEPA (United States Environmental Protection Agency) that THMs should not be greater than 0.10 mg/l. The high concentrations of THMs will lead to health complications [1].
