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Relative Importance of Nitrite Oxidation by Hypochlorous Acid under Chloramination Conditions
Citation:
WAHMAN, D. G. AND G. E. Speitel, Jr. Relative Importance of Nitrite Oxidation by Hypochlorous Acid under Chloramination Conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY. ACS Publications, Washington, DC, 46(11):6056-6064, (2012).
Impact/Purpose:
To inform the public.
Description:
The importance of nitrite’s oxidation by tree chlorine under chloramination conditions was evaluated using batch kinetic experiments and a chloramine model implemented into the computer program AWUASIM. The experimental data was best represented with the inclusion of a reaction between free chlorine and nitrite. Using the experimental data, general acid assisted rate constants for carbonic acid and bicarbonate ion were estimated for the reaction between nitrite and monochloramine. The chloramine model was subsequently used to conduct simulations to characterize the importance of the free chlorine reactions with nitrite for typical chloramination conditions. The relative importance of nitrite’s reaction with free chlorine versus monochloramine increased with (1) decreasing nitrite concentration, (2) increasing chlorine to nitrogen mass ratio, and (3) decreasing monochloramine concentration; and (4) peaks between pH 7.5 to 8.5 for typical chloramination conditions. Based on these results, nitrite’s reaction with free chlorine may be important during chloramination and should be included in water quality models to simulate monochloramine’s fate.
