What can occur if too much ammonia is added to a chloramination system?

Document ID

Document ID TE188

Version

Version 2.0

Status

Status Published

Published Date

Published Date 27/05/2017
Question
What can occur if too much ammonia is added to a chloramination system?
Summary
Chloramination and Feeding Ammonia
Answer
Excess of ammonia will cause bacteria to grow, which can lead to biofilms or nitrification. Nitrifying bacteria convert excess ammonia to nitrite and ultimately to nitrate. Biofilms and nitrite will consume the monochloramine disinfectant. The system will also be affected in the following ways:

• Nitrate increases - Federal MCL of 10 mg/L NO3-N (maximum contamination level, heath effects e.g. blue baby syndrom)
• Ammonia decreases
• DO decreases
• pH decreases (more acidic)
• Alkalinity decreases
• Bacteria increase (biofilm).
• Chloride increases as monochloramine is consumed due to the following:
• NH2Cl --> NH3 + Cl- (chloride)