Influencing pathways and toxicity changes of pre-ozonation on carcinogenic NDEA formation from greenhouse gas adsorbent DEAPA in subsequent disinfection processes

This study was to evaluate the feasibility of controlling carcinogenic nitrosodiethylamine (NDEA) formation from greenhouse gas adsorbent 3-diethylaminopropylamine (DEAPA) by pre-O 3 in subsequent chlorination/chloramination processes. The result indicated that the NDEA yields (0.4 %) during chlorination was 1.3 times of that during chloramination (0.3 %); pre-oxidation with 4 mg/L O 3 significantly cut down its formation; the reduction rates were up to 67.5 and 48.5 %, respectively. OH scavenger greatly augmented the final NDEA amount from 1.86 to 5.05 μg/L during ozonation , while its roles on subsequent processes differed with disinfection methods as well as O 3 (g) dosages. Most of co-existed substances inhibited NDEA generation, except NO 2 − , CO 3 2− and SO 4 2− , which slightly promoted during ozonation. Basing on Gaussian calculation, GC/MS and UPLC-Q-TOF-MS analysis, the influencing mechanisms of pre-O 3 on NDEA formation in subsequent disinfection processes were proposed. In addition, the calculated toxicity analysis as well as the whole toxicity was applied to evaluate the possibility of pre-O 3 on risk control.