Standard Article


Water Quality Control

  1. Absar A. Kazmi

Published Online: 15 JUL 2005

DOI: 10.1002/047147844X.wq181

Water Encyclopedia

Water Encyclopedia

How to Cite

Kazmi, A. A. 2005. Chlorination. Water Encyclopedia. 2:88–91.

Author Information

  1. Nishihara Environment Technology, Tokyo, Japan

Publication History

  1. Published Online: 15 JUL 2005


Chlorine in its various forms is invariably and almost universally used for disinfecting water supplies. It is cheap, reliable, easy to handle, easily measurable, and above all, it is capable of providing residual disinfecting effects for long periods, thus affording complete protection against future recontamination of water in distribution system. At low concentrations, chlorine probably kills microorganisms by penetrating the cell and reacting with the enzymes and protoplasm. At higher concentrations, oxidation of the cell wall destroys the organism. Chlorination also removes soluble iron, manganese, and hydrogen sulfide from water.


  • break-point chlorination;
  • chlorine;
  • chlorination;
  • disinfection;
  • hypochlorite;
  • trihalomethanes (THM)