Implications of breakpoint chlorination on chloramines decay and disinfection by-products formation in brine solution

The effects of breakpoint chlorination on formation and decay of inorganic chloramines and disinfection by-products (DBPs) in chlorinated brine solutions is investigated. A correlation was established between the decay and speciation of chloramines with the environmental factors such as pH, temperature, chlorine to ammonia ratio and natural organic matter dosage. Results showed that acidic pH and high chlorine to ammonia ratio favored the formation of trichloramine (NCl3), however neutral and high pH favored the formation of monochloramine (NH2Cl) and dichloramine (NHCl2) species. Further, the presence of natural organic matter (NOM) and higher pH enhanced the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) in the chlorinated brine solution. Further, kinetics simulations were performed to study the chloramine formation and decay kinetics as a function of temperature using web-based application designed by US Environmental protection Agency (EPA). Based on comparisons between simulated and experimental datasets, a close similarity was observed between chloramine chemistry synthetic chlorine system and chlorinated brine solution. Moreover, the mechanism of chloramine formation and decay has been proposed based on the model simulations and N2, ammonia and NO3− being identified as the main products.