Disinfection of water involves dosing the water chemically to kill bacteria, parasite and viruses present in the water.

Use of chemical allows dose rates to be such that residual levels of chemicals dosed provide effective disinfection of the water for extended time periods up to its intended use.

Liquid chlorine or chlorine gas are the common forms of chemical used for disinfection.

AWS chlorinates using sodium hypochlorite in a chlorine loop with an analyser or calcium hypochlorite granules and tablets.