Disinfection is the process of selectively destroying or inactivating pathogenic organisms present in water, usually by chemical means. Disinfection aims in reducing the organisms in water to such low levels that no infection of disease results when the water is used for domestic consumption including drinking. Sterilization is the complete destruction of all organisms found in water by boiling, which is usually expensive and unnecessary. Disinfection is, therefore, different from sterilization and is a required part of the water treatment process. Disinfectant is the chemical used for disinfection of water. The common disinfectant used for the disinfection of water is chlorine.
Some common pathogens (disease causing organisms) and the waterborne diseases transmitted by them are listed below.
Thermal death points of some common pathogens and contact times are furnished in the Table below.