Modeling the distribution of chloramines during drinking water chloramination

Chloramination is likely to become an even more common fonn of drinking water disinfection. To date, the impact of organic chloramine formation on the chloramination process has not been assessed. The purpose of the present work was to apply an existing kinetic model for chlorine transfer to typical conditions of drinking water chloramination. In particular, the impact of treatment conditions (chlorine-to-ammonia ratio, chlorine dose, reaction time, and pH) on monochloramine residuals was assessed. Model simulations indicate that organic chloramine fonnation may be significant under typical conditions of drinking water chloramination. Residual inorganic monochloramine concentrations were relatively insensitive to pH, contact time, and chlorine-to-ammonia ratio, but increased with decreasing organic N and/or increasing chlorine dose.