Dissolved inorganic nitrogen as an overlooked precursor of nitrogenous disinfection byproducts - A critical review

• Published in: Water research (Oxford) 2025-01, Vol.268 (Pt A), p.122654, Article 122654
• Main Authors: Li, Xiao, Bond, Tom, Tan, Xiaoyu, Yang, Haolin, Chen, Yuheng, Jin, Bingbing, Chen, Baiyang
• Format: Article
• Language: English
• Subjects: ammonia; Ammonia - chemistry; chlorination; chloropicrin; disinfectants; Disinfectants - chemistry; Disinfection; Dissolved inorganic nitrogen; Dissolved organic nitrogen; Formation potential; nitrates; nitrites; Nitrogen - chemistry; Nitrogen source; Nitrogenous disinfection byproducts; nitrosamines; toxicity; water; water management; Water Pollutants, Chemical - chemistry; Water Purification
• ISSN: 0043-1354; 1879-2448; 1879-2448
• DOI: 10.1016/j.watres.2024.122654

•DIN may promote, inhibit, or not alter N-DBP formation depending on many influencing factors.•Nitrite and ammonia usually enhance TCNM and NDMA formation, but exceptions exist.•Nitrate promotes HNM in UV processes, but otherwise does not affect N-DBP formation.•Chloramine can increase HANs, HNMs, NAs, and HAcAms formation.•Both DIN and DON can be nitrogen sources of N-DBP but their relative roles are unclear now. Aquatic nitrogenous compounds can be classified as dissolved organic nitrogen (DON) and dissolved inorganic nitrogen (DIN), including ammonia, nitrite, nitrate, and inorganic chloramines. The occurrence of nitrogenous disinfection byproducts (N-DBPs) in water, such as haloacetonitriles (HANs), halonitromethanes (HNMs), haloacaetamides (HAcAms), and nitrosamines (NAs), has attracted considerable attention due to their higher toxicity than regulated carbonaceous analogues. While numerous studies have investigated the contributions of DON to N-DBP formation, relatively fewer studies have explored DIN as N-DBP precursors, although DINs are sometimes evaluated as influencing factors. Through a literature review and data mining, this study delves into the existing body of evidence that analyze the contributions of different forms of DIN to N-DBP generation. The results showed that ammonia and nitrite can enhance trichloronitromethane (TCNM) and nitrodimethylamine (NDMA) formation in conventional chlorination and chloramination processes, nitrate can promote HNM formation in ultraviolet-based processes, and monochloramine can increase HAN, HAcAm, HNM, and NDMA formation in most disinfection scenarios. Notably, some experiments demonstrated that the yields of dichloroacetonitrile (DCAN) and TCNM can be higher from reactions involving nitrogen-free organic precursors and DIN than those involving DON and nitrogen-free disinfectant, suggesting that the relative importance of DON and DIN in forming N-DBP in real water remains unresolved. These insights thus underscore DIN as a non-negligible precursor in N-DBP formation and call for more attention to water management strategies for DIN. [Display omitted]