Ammonia is fed at about what percent of the amount of chlorine used?

• A. 20% to 25%
• B. 25% to 33%
• C. 30% to 40%
• D. 40% to 50%

Answer: (A)

In a chloramination setup, chlorine does the heavy lifting for disinfection, and ammonia is added in a controlled, smaller amount to convert a portion of that chlorine into chloramines. This produces a more stable residual in the distribution system and helps limit the formation of disinfection byproducts. The key idea is to dose ammonia just enough to form chloramines but not so much that ammonia or excess chloramines remain in the system. If too little ammonia is fed, chloramines won’t form adequately and free chlorine can dominate; if too much ammonia is fed, residual ammonia and excessive chloramines can cause taste/odor issues and other operational problems. So, the ammonia dose is kept as a relatively small share of the chlorine dose.