Seasonal Variation of Chloramines and Free Chlorine in Niwakubo Water Treatment Plant, Osaka Prefecture.

Abstract

The behavior of monochloramine, dichloramine and free chlorine in a water treatment plant was examined during three year with the continuous flow method of simultaneous determination. At the point just after prechlorination, the predominant species were dichloramine (from November to March) and free chlorine (from May to September). The concentration of dichloramine decreased to 1/3 with increase in pH from 6.4 to 6.9. The decomposition rate of dichloramine in daytime showed an increase of 10% over that in night. Dichloramine converted to free chlorine at the rate of 18%.