Chlorine binding capacity

Hypochlorous acid, formed when chlorine dissolves in water, is antimicrobial. This is the basis for the use of chlorine and halazone in water purification. Organic matter binds chlorine, thus preventing antimicrobial actions. In a given water sample, this process is referred to as the chlorine demand, since the chlorine-binding capacity of the organic material must be exceeded before bacterial killing is accomplished. Many preparations of chlorine for water purification do not eradicate all bacteria or entamoeba cysts. 

Chemical Chlorine Demand or Chlorine Binding Capacity... 

Microorganisms and other components in water consume some chlorine gas. This property has to be measured to know how much disinfectant is needed for water treatment. The chlorine binding capacity is expressed as mg/dm. ... 

The following formula is used to calculate the chemical chlorine demand, or the chlorine binding capacity ... 

As a rule, sterile glass-stoppered bottles with a capacity of 250 to 500 ml are used for sampling. These are sterilized in the laboratory and safeguarded against secondary infection with aluminium foil. Bottles used for sampling chlorinated water must be treated with sodium thiosulfate before sterilization. A 250 ml bottle should be charged with 0.25 ml of a solution of 0.01 m sodium thiosulfate and a 500 ml bottle with 0.5 ml of the same solution in order to bind immediately any chlorine or chloramine which may... 

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