N-nitrosodimethylamine (NDMA) formation potential of amine-based water treatment polymers: Effects of in situ chloramination, breakpoint chlorination, and pre-oxidation

Determinants of disinfectant pretreatment efficacy for nitrosamine control in chloraminated drinking water

“…The HOCl preoxidation results with water 10 suggest the possibility that at sufficiently high HOCl exposure-to-polymer ratios, HOCl may produce a net reduction in NDMA precursors. Previous work with polyDADMAC in deionized water had observed an increase in NDMA formation from pretreatment with O 3 , but not HOCl (Selbes et al, 2014;Park et al, 2015), in line with the lower effect of HOCl pretreatment we observed here.…”

“…Previous work demonstrated that pretreatment of model precursors or natural waters with free chlorine (HOCl; used here to represent the sum of free chlorine species) (Charrois and Hrudey, 2007;Chen and Valentine, 2008;Selbes et al, 2014), ozone (O 3 ) (Lee et al, 2007;Selbes et al, 2014), chlorine dioxide (ClO 2 ) (Lee et al, 2007), permanganate (Chen and Valentine, 2008) or ferrate (Lee et al, 2008) generally reduced NDMA formation during subsequent chloramination. However, pretreatment of polyDADMAC in deionized water either did not affect (HOCl and ClO 2 ) or increased (O 3 ) NDMA formation during post-chloramination (Selbes et al, 2014;Park et al, 2015).…”

The effect of pre-oxidation on NDMA formation and the influence of pH

“…3b). In a study conducted by Park et al (2014), similar findings have been reported. In that study, pre-oxidation with chlorine dioxide has shown approximately 20% decreases in NDMA FP from PolyDADMAC and PolyAMINE.…”

“…3a). However, a study conducted by Park et al (2014) has shown a decrease in NDMA FP (~50%) during pre-chlorination of PolyDADMAC and PolyAMINE. The steady trend observed in our study was attributed to the hindrance of nucleophilic substitution by the positive charge on the nitrogen atoms of polymers (Krasner et al, 2013).…”

Control of Nitrosamines, THMs, and HAAs in Heavily Impacted Water with O3‐BAC

“…Although preozonation had very little impact, mid‐ozonation destroyed (transformed) 43% of the total nitrosamines' FP, which indicated some precursors were readily oxidized with a sufficient ozone dose, because ozonation can be an effective oxidant (Shah et al 2012). However, in other studies, ozone was found to cause NDMA formation rather than prevent it, especially during ozonation of wastewater and coagulant polymers (Gerrity et al 2015, McCurry et al 2015, Park et al 2014), which is different from the result in this study. Perhaps the characteristics of nitrosamine precursors are different.…”