UV/chlor(am)ine are efficient for achieving multiple-barrier disinfection and maintaining residuals, while bromide (Br⁻) has notable impacts on the formation and toxicity of halonitromethanes (HNMs) during UV/chlor(am)ine disinfection. This study investigated the effects of Br⁻ on HNMs formation and toxicity alteration during UV/chlor(am)ine disinfection of nitrate containing humic acid (HA) water. Results reveal that the maximum concentration of HNMs during UV/chlorine disinfection was 12.03 μg L⁻¹ with 0.2 mg L⁻¹ Br⁻, which was 22.5% higher than that without Br⁻, and the predominant species of HNMs were converted from trichloronitromethane (TCNM) to dibromonitromethane (DBNM) and tribromonitromethane (TBNM). However, the maximum concentration of HNMs during UV/chloramine disinfection was 3.69 μg L⁻¹ with 0.2 mg L⁻¹ Br⁻, which was increased by 26.0% than that without Br⁻, and the predominant species of HNMs were converted from dichloronitromethane (DCNM) to bromochloronitromethane (BCNM) and DBNM. Notably, the HNMs species and yields during UV/chloramine disinfection were less than those during UV/chlorine disinfection, primarily due to the higher concentrations of HO· and reactive chlorine/bromine species in UV/chlorine. Also, in the ranges of the Br⁻:Cl₂ molar ratio from 0 to 0.32 and pH from 6.0 to 8.0, the Br⁻:Cl₂ molar ratio of 0.16 and acidic pH contributed to the HNMs formation during UV/chlorine disinfection, and a high Br⁻:Cl₂ molar ratio and neutral pH contributed to the HNMs formation during UV/chloramine disinfection. Note that the incorporation of Br⁻ significantly improved the calculated cytotoxicity (CTI) and genotoxicity (GTI) of HNMs formed, and the calculated CTI and GTI of HNMs formed during UV/chloramine disinfection were 28.19 and 48.90% of those during UV/chlorine disinfection. Based on the diversity of nitrogen sources, the possible formation pathways of HNMs from nitrate containing HA water were proposed during UV/chlor(am)ine disinfection in the presence of Br⁻. Results of this study indicated that UV/chloramine can reduce the formation and toxicity of HNMs efficiently.

UV/chlor(am)ine 可有效实现多重屏障消毒和保持残留物，而溴化物 (Br ^- ) 在 UV/chlor(am)ine 消毒过程中对卤代硝基甲烷 (HNMs) 的形成和毒性具有显着影响。本研究调查了在对含有腐植酸 (HA) 的硝酸盐进行紫外线/氯胺消毒期间Br ^{-对 HNM 形成和毒性变化的影响。}结果表明，在紫外线/氯消毒过程中，HNMs 的最大浓度为 12.03 μg L ^-1和 0.2 mg L ^-1 Br ^-，比没有 Br ^{-时高 22.5%}, HNMs 的主要种类从三氯硝基甲烷 (TCNM) 转变为二溴硝基甲烷 (DBNM) 和三溴硝基甲烷 (TBNM)。然而，在紫外线/氯胺消毒过程中，HNMs 的最大浓度为 3.69 μg L ^-1和 0.2 mg L ^-1 Br ^-，比没有 Br ^-时增加了 26.0% ，并且 HNMs 的主要种类由二氯硝基甲烷转化而来（ DCNM) 为溴氯硝基甲烷 (BCNM) 和 DBNM。值得注意的是，紫外线/氯胺消毒期间的 HNMs 种类和产量低于紫外线/氯消毒期间的那些，这主要是由于紫外线/氯中 H2O·和活性氯/溴种类的浓度较高。此外，在 Br ^- :Cl的范围内₂摩尔比从 0 到 0.32，pH 从 6.0 到 8.0，0.16 的 Br ^- :Cl ₂摩尔比和酸性 pH 有助于紫外线/氯消毒过程中 HNMs 的形成，高 Br ^- :Cl ₂摩尔比和中性在紫外线/氯胺消毒过程中，pH 有助于 HNMs 的形成。请注意，Br 的加入^-显着提高了形成的HNMs的计算细胞毒性（CTI）和遗传毒性（GTI），UV/氯胺消毒过程中形成的HNMs的计算CTI和GTI分别是UV/氯消毒过程中的28.19%和48.90%。^{基于氮源的多样性，提出了在 Br -}存在下 UV/氯胺消毒过程中含硝酸盐的 HA 水中 HNMs 的可能形成途径。这项研究的结果表明，UV/氯胺可以有效地减少 HNMs 的形成和毒性。