Is there a quick reference guide on what to look for to ensure optimal chloramination for disinfection.

Document ID

Document ID TE12809

Published Date

Published Date 07/01/2022
Question
Is there a quick reference guide on what to look for to ensure optimal chloramination for disinfection.
Summary
Chloramination Curve
Answer
The chloramination curve has 3 sections.  For an ideal level of monochloramine for disinfection most processes should be at the end of zone 1 but not yet into zone 2.  Knowing what zone you are in can be relatively simple to figure out if you know what to look for.  When in zone 1 you will see total chlorine, monochloramine, total ammonia and free ammonia.  In zone 2 you will see total chlorine, monochloramine and total ammonia, but NO free ammonia.  In zone 3 you will see only chlorine, free and total chlorine should be very similar or match, and NO ammonia.
Since the optimal state is at the end of zone 1, the easiest way to ensure you are still in zone 1 but close to the threshold for zone 2 is to look for only trace levels of free ammonia.  See the below graphs showing a star where there are trace levels of free ammonia and close to maximum monochloramine residual (please note this graph is simplified for this summary, more detail can be found in the links below). 



What exactly does trace levels of free ammonia mean? That depends on several factors, such as water temperature and pH. Normally it is around 0.1 ppm of free ammonia, but in some situations, up to 0.2 ppm (lower temperature, higher pH, shorter distribution network), or rather <0.05 ppm (higher temp, longer network), etc.
 

Was this answer helpful?

Submitting...
Thank you for your feedback!
There was an error with your submission. Please try again.