Formation and Fate of Nitromethane in Ozone-Based Water Reuse Processes
Formation and Fate of Nitromethane in Ozone-Based Water Reuse Processes
复制标题
臭氧水回用过程中硝基甲烷的形成和去向
DOI：
10.1021/acs.est.0c07895
复制
发表时间：
2021
影响因子：
11.4
通讯作者：
McCurry, Daniel L.
中科院分区：
文献类型：
--
作者：
Shi, Jiaming Lily;Plata, Sophia L.;Kleimans, Marco;Childress, Amy E.;McCurry, Daniel L.
臭氧氧化法广泛应用于污水回用处理系统中，用于微污染物控制或在某些回用工艺中用作消毒剂和预氧化剂。我们最近发现二级出水臭氧化产生硝基甲烷，硝基甲烷可以通过氯化有效地转化为遗传毒性的卤代硝基甲烷。在这项工作中，通过分析来自五个使用臭氧的回用操作的样品，表征了硝基甲烷通过水回用处理列车的命运。储备渗透（RO）对硝基甲烷的去除率很差（<50%），紫外线/高级氧化（UV/AOP）不能去除硝基甲烷，在某些情况下，还会增加硝基甲烷的去除率。经过深度处理后，硝基甲烷仍然充足，当添加氯模拟二次消毒时，始终观察到卤硝基甲烷的形成。相比之下，生物活性炭去除大部分硝基甲烷（约75%）。通过实验验证了RO在清洁系统和废水中的低去除率，并量化了UV/AOP对硝基甲烷的直接和间接光解动力学。对AOP过程中硝基甲烷浓度的增加提出了解释。这些结果表明，硝基甲烷对直接饮用水回用系统具有独特的危害，因为它在废水臭氧化过程中普遍存在，RO和UV/AOP去除效果差，并且在添加氯后容易转化为遗传毒性的卤代硝基甲烷。
Ozonation is widely used in wastewater reclamation treatment trains, either for micropollutant control or as a disinfectant and preoxidant in certain reuse processes. We recently found that ozonation of secondary effluent produces nitromethane, which can be efficiently transformed to genotoxic halonitromethanes by chlorination. In this work, the fate of nitromethane through water reuse treatment trains was characterized by analyzing samples from five reuse operations employing ozone. Nitromethane was poorly (<50%) rejected by reserve osmosis (RO), not removed by, and in some cases, increased by ultraviolet/advanced oxidation processes (UV/AOP). Sufficient nitromethane remained after advanced treatment that when chlorine was added to mimic secondary disinfection, halonitromethane formation was consistently observed. In contrast, biological activated carbon removed most (>75%) nitromethane. Bench-scale experiments were conducted to verify low removal by RO in clean systems and with wastewater effluent and to quantify the kinetics of direct and indirect photolysis of nitromethane in UV/AOP. An explanation for increasing nitromethane concentration during AOP is proposed. These results indicate that nitromethane presents a unique hazard to direct potable reuse systems, due to its ubiquitous formation during wastewater ozonation, poor removal by RO and UV/AOP, and facile conversion into genotoxic halonitromethanes upon chlorine addition.