Formation and speciation of haloacetamides and haloacetonitriles for chlorination, chloramination, and chlorination followed by chloramination.

The formation of haloacetamides (HAcAms) and haloacetonitriles (HANs) from a solution containing natural organic matter and a secondary effluent sample was evaluated for disinfection by chlorination, chloramination, and chlorination followed by chloramination (ClNHCl process). The use of preformed monochloramine (NHCl) produced higher concentrations of HAcAms and lower concentrations of HANs than chlorination, while the ClNHCl process produced the highest concentrations of HAcAms and HANs. These results indicate that the ClNHCl process, which inhibited the formation of regulated trihalomethanes compared with chlorination, enhanced the formation of HAcAms and HANs.