When disinfecting with chloramines, when can the ammonia be added to the process?

When disinfecting with chloramines, when can the ammonia be added to the process?

• A. Before the chlorine
• B. Same time as the chlorine
• C. After the chlorine
• D. All of the above

Answer: (D)

Chloramines form when ammonia is present while chlorine is in the water, so the ammonia can be added before, at the same time as, or after the chlorine and still produce chloramines. If you add ammonia first, chlorine is then introduced and reacts with that ammonia to form chloramines. If you dose them at the same time, they meet and react immediately to form chloramines. If you add ammonia after chlorine, the chlorine has already done its work and the ammonia converts the remaining chlorine species into chloramines. The key is controlling the chlorine-to-ammonia ratio and other conditions (like pH) to favor monochloramine and a stable residual. This is why all of the above timing options can be used.

Chloramines form when ammonia is present while chlorine is in the water, so the ammonia can be added before, at the same time as, or after the chlorine and still produce chloramines. If you add ammonia first, chlorine is then introduced and reacts with that ammonia to form chloramines. If you dose them at the same time, they meet and react immediately to form chloramines. If you add ammonia after chlorine, the chlorine has already done its work and the ammonia converts the remaining chlorine species into chloramines. The key is controlling the chlorine-to-ammonia ratio and other conditions (like pH) to favor monochloramine and a stable residual. This is why all of the above timing options can be used.