Disinfection using monochloramine (NH2Cl) has been associated to the formation of nitrogenous DBPs (N-DBPs, e.g., NDMA) of higher toxicity than regulated DBPs (THMs and HAAs). The formation of N-DBPs such as haloacetonitriles (HANs) and haloacetamides (HAcAms) has also been associated with the presence of dissolved organic nitrogen in waters impacted by algae or by wastewater (i.e., presence of nitrogenous organic compounds such as amino acids). However, recent studies suggested that inorganic nitrogen from NH2Cl plays a substantial role in HANs and HAcAms formation, especially from humic substances. Halonitriles and haloamides formation has been reported from the reaction between NH2Cl and aldehyde or ketone groups; however, studies about the formation of HAcAms from other model compounds are limited.  The aim of this study was to investigate the formation of HANs and HAcAms during the chloramination of various organic matter isolates (River NOM: Suwannee - USA, Blavet, Gartempe and Ribou � France; wastewater effluents organic matter isolated from the Jeddah treatment plant (EfOM) - hydrophobic, transphilic and colloidal fractions) and model compounds (simple benzene derivatives: phenol, resorcinol, benzoquinone, benzoic acid).  All experiments were performed using labelled 15NH2Cl to track the nitrogen incorporation into DBP structure. Results of DBP formation potentials (excess of NH2Cl, 72h of contact time, pH 8) showed a higher formation of HAcAms from highly aromatic fractions (Suwannee NOM) than from isolates enriched in nitrogen (EfOM).  Formation kinetics of HAcAms from Suwannee river NOM showed a slow incorporation of nitrogen from NH2Cl. Kinetics from EfOM showed a different behavior: A fast increase in the first hours of reaction, indicating the presence of specific nitrogenous precursors, and then slow incorporation of NH2Cl. The influence of several parameters (pH, bromide ion concentration) will be presented. The chloramination of aromatic compounds confirmed the possible formation of HAcAms and incorporation of inorganic nitrogen.

Formation of nitrogenous disinfection byproducts by chloramination of various organic matter fractions and aromatic model compounds

248th National Meeting (2014)

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