Chlorine, dissolved in liquid, is one of the most
effective and economical germ-killers for the
treatment of water to make it potable or safe to
drink. Chlorine's powerful disinfectant qualities
come from its ability to bond with and destroy the
outer surfaces of bacteria and viruses. Drinking
water chlorination is one of the most widely used
methods to safeguard drinking water supplies. In
addition to water disinfection, chlorine and its
derivatives are used to treat sewage and industrial
effluent, and as household and industrial bleaches
(eg., to control biological agent growth in water
filled industrial systems) to maintain and improve
hygiene standards.