CHLORINE BREAKPOINT

(Water Treatment) The point at which the chlorine dosage in a water treatment process has satisfied the Chlorine Demand. To eliminate the taste and odor associated with processed water, sufficient chlorine must be added to reach the breakpoint. Increasing the chlorine dose beyond the breakpoint produces a free chlorine residual, which is free to kill microorganisms. When chlorine is added to water, it first combines with constituents in the water such as iron, manganese, and nitrites. It is important to add enough chlorine to the water initially to ensure that these constituents are oxidized and to ensure that a residual is formed to react with the ammonia and organic matter in the water. Taste and odor problems result when chlorine dosages are either below the breakpoint, or well beyond the breakpoint.