Modeling drinking water chlorination at the breakpoint: I. Derivation of breakpoint reactions

Abstract

From a bibliographic synthesis on the reactions that can occur during breakpoint chlorination. We carry out the stability study of produced entities under the applied conditions in the potable water production, where the pH range 6.5–8.5, and the initial weight ratio Cl/N including in 10/1–15/1 at ambient temperature. The choice of dominant species and reactions that have been taken into account must be based on data of the thermodynamics and the kinetics governed by pH and temperature. Through this selection appears a large disagreement in results of researches between the rate expressions of the kinetics and observed and even with the empirical results, especially for reaction the monochloramine formation and for equilibrium the formation-hydrolysis of trichloramine. Then, the nature of identified intermediate and the observed rate of its formation reaction were not agree in different published works, as well the possibility of destruction of the free chlorine residual by this intermediate is not confirmed yet. Through this study, we obtain a representative selected group of reactions during breakpoint chlorination process, this identified group of reactions is compared with other models of breakpoint reactions proposed in the literature, where some differences appear.

Keywords:

• Drinking water
• Chlorination
• Breakpoint
• Modeling
• Set reactions

Acknowledgment

We thank Prof. S. Samra for the revision and correction of the present work.