Well,

However, due to present concerns for minimizing the formation of chlorine byproducts, the use of prechlorination is being supplanted by the use of other chemical oxidants (e.g., ozone, permanganate) for the control of biological fouling, odor, or reduced iron or manganese.

In pilot plant studies, Means et al. (1986b) found that concurrent and sequential methods (chlorine at rapid mix and ammonia at end of flocculation tank) gave better performance at removing m-SPC bacteria than preammoniation (but poorer than free chlorination). Concurrent addition gave about as low a TTHM value as preammoniation. In the presence of concentrations of organic nitrogen similar to ammonia, pre reacted chloramines may give better performance than dynamically formed chloramines from preammoniation due to the favorable competition for chlorine by many organic N compounds (and their low biocidal potency) relative to inorganic nitrogen (Wolfe and Olson, 1985).

Regards

Thank you Bayan. Yes, monochloramines are recommended disinfection methods for those systems having issues with disinfection by-product formation. Are you aware of any plant or pilot study of monochloraminated drinking water system measuring free chlorine at the distribution system or just after chloramination? Any reference would be much appreciated. I am interested in the operational aspect of the system regarding monitoring parameters to assure the system is performing as expected.

I support the very appreciative explanations given by Dr Bayen Hussien.