Question

Breakpoint chlorination of water involves addition of chlorine in an amount sufficient to

• A. react with inorganic matter
• B. kill giardia cysts
• C. react with any ammonia and readily oxidizable organic matter.
• D. reduce bacteria growth in filters

Answer 1

The correct option is C react with any ammonia and readily oxidizable organic matter.

Breakpoint Chlorination

All chlorine added reacts with any organic materials present until they are destroyed.

Chlorine then reacts with amino acids or urea.
The products of this reaction are called chloramines.

If more chlorine is added, the chloramines are themselves broken down until there is nothing left to react.
At this point chlorine begins to appear as 'free chlorine residual'

This point is the breakpoint.



Note: Breakpoint chlorination curve when no ammonia or organics are present -