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

• Published in: The Science of the total environment 2023-05, Vol.873, p.162355-162355, Article 162355
• Main Authors: Liu, Tianze, Liao, Xiaobin, Lin, Xinna, Yu, Jing, Qi, Huan, Jiang, Zhibin, Zou, Jing, Li, Qingsong
• Format: Article
• Language: English
• Subjects: Carcinogens - toxicity; Chloramination; Chlorination; Diethylnitrosamine; Disinfection - methods; Disinfection by-products; Greenhouse Gases; Halogenation; Nitrosamines; Ozone; Pre-oxidation; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - toxicity; Water Purification - methods
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.162355

This study was to evaluate the feasibility of controlling carcinogenic nitrosodiethylamine (NDEA) formation from greenhouse gas adsorbent 3-diethylaminopropylamine (DEAPA) by pre-O3 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 O3 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 O3(g) dosages. Most of co-existed substances inhibited NDEA generation, except NO2−, CO32− and SO42−, which slightly promoted during ozonation. Basing on Gaussian calculation, GC/MS and UPLC-Q-TOF-MS analysis, the influencing mechanisms of pre-O3 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-O3 on risk control. [Display omitted] •The NDEA amount formed during chlorination of DEAPA was 1.3 times of that during chloramination.•Pre-O3 significantly cut down NDEA formation in subsequent disinfection processes.•Roles of OH scavenger on NDEA formation differed with disinfection methods and pre-O3 dosages.•Pre-O3 facilitated the formation of intermediates with lower NDEA yields than parent compound DEAPA.•Pre-O3 had a positive effect on overall toxicity control evaluated by BioFix®Lumi bacteria.