· Residual chlorine and free chlorine is an
important parameter and is a measure of the amount of available chlorine
remaining in water system after the chlorination.
· Residual chlorine is the amount of chlorine that
remains in the water after chlorination.
· When sodium hypochlorite (NaoCl) is dissolved in
water it produces hypochlorous acid and hypochlorite ion.
· These hypochlorite ions are called as free
chlorine.
· This free chlorine is responsible for the
chlorination of the microbes in water.
· All the free chlorine is not consumed in the
chlorination.
· This remaining chlorine is called residual
chlorine.
