Break
Point
Chlorination - If the water to be chlorinated contains significant amounts of ammonia the amount of chlorine added will be sufficient only to form monochloramine. Further addition of chlorine may lead to formation of di-or tri-chloramines. But their formation can be prevented by maintaining the chlorine to nitrogen ratio very low.
Thus a breakpoint is reached where no ammonia or monochloramine is left in the solution and no free available chlorine is present. After this stage, further addition of chlorine produces free available chlorine in water. Adding chlorine to exceed the breakpoint is called breakpoint chlorination.
