光照对再生水氯消毒副产物及其细胞毒性的控制机制与强化原理

Chlorination is widely used for the control of pathogenic risks in reclaimed water. However, high concentrations of disinfection byproducts (DBPs) will be formed after reclaimed water chlorination, which can cause the significant increase of reclaimed water cytotoxicity on mammalian cell. The previous studies found that sunlight irradiation and UV irradiation can degrade some DBPs and reduce the reclaimed water cytotoxicity, but the related control mechanisms are still unclear. This research aims to control reclaimed water chlorination DBPs and cytotoxicity. For the process of sunlight irradiation during reclaimed water storage, the research will study the effects of sunlight irradiation and its UV wavelengths on the removal of highly toxic chlorination DBPs such as haloacetamide and organic halogen (AOX), the removal characteristics of cytotoxicity, and other influential factors such as water quality and irradiation conditions. The mechanism of sunlight and its derived free radical on the control chlorination DBPs and cytotoxicity will be elaborated. The chlorination DBPs degradation and cytotoxicity removal characteristics as well as the correlation of DBPs and cytotoxicity removal will be well understood. The removal characteristics of reclaimed water chlorination DBPs and its cytotoxicity by LED UV/peroxysulphate will also be analyzed. A novel LED UV catalysis-sunlight storage technology will be proposed, which will provide technological support for the control of chlorination DBPs and its cytotoxicity, and guarantee of reclaimed water utilization safety.

氯消毒被广泛应用于再生水病原微生物风险控制，但是再生水氯消毒后将生成较高浓度的消毒副产物，导致再生水对哺乳动物细胞的毒性显著增加。前期研究发现，太阳光照及紫外线照射可降解部分消毒副产物，并降低再生水细胞毒性，但相关控制机制尚不清楚。本研究以控制再生水氯消毒副产物及其细胞毒性为目标，围绕再生水储存过程中的光照环节，研究太阳光及其紫外线对卤乙酰胺、有机卤化物等高毒性氯消毒副产物及其细胞毒性的去除特性及光照条件和水质条件的影响；阐明光照及其衍生的自由基对氯消毒副产物及细胞毒性的控制机制；掌握再生水光照过程中氯消毒副产物降解和细胞毒性去除特性及两者的关联性，提出再生水储存的光照条件和水质要求；研究发光二极管紫外线（LED UV）/过硫酸盐等紫外线催化对再生水氯消毒副产物及其细胞毒性的去除特性，提出LED UV催化-光照储存技术，为控制氯消毒副产物及其毒性、保障再生水利用安全提供技术支撑。

再生水氯消毒副产物的风险不容忽视。太阳光照可降解部分消毒副产物，但相关控制机制尚不清楚。本研究以控制再生水氯消毒副产物及其细胞毒性为目标，围绕再生水储存过程中的光照环节，研究太阳光对典型消毒副产物及其细胞毒性的去除特性；阐明光照对氯消毒副产物及其细胞毒性的控制机制；掌握光照过程中消毒副产物和细胞毒性去除特性及两者的关联性，提出消毒副产物及毒性的强化控制技术，为保障再生水利用安全提供技术支撑。本研究所取得的主要成果如下：. 再生水光照后经氯消毒，二氯乙腈等高毒性含氮消毒副产物生成潜能显著降低。光照对二氯乙腈、二氯丙酮和三氯丙酮生成潜能的降解满足一级反应动力学方程。光照可有效降低氯消毒过程中的细胞毒性生成潜能（CtFP）。光照24 h后（可见光强60 mW/cm2，紫外光强1 mW/cm2），CtFP的去除率约为40%。太阳光中紫外线波段对副产物和细胞毒性生成潜能去除起主要作用。. 再生水经光照后，三维荧光强度、紫外吸光度明显降低，且符合一级动力学模型。三维荧光强度可作为替代指标指示二氯乙腈生成潜能。光照将再生水中溶解性有机氮转化为氨氮，从而降低了卤乙酰胺等含氮消毒副产物生成潜能。运用中间媒介电化学氧化法，发现光照降低了溶解性有机物供电子能力（EDC），从而减少了后续氯消毒过程中卤代副产物和细胞毒性生成。. 发现光照可以去除氯消毒后再生水的细胞毒性。光照12 h后，细胞毒性可降低约75%，但余氯会阻碍细胞毒性降低。光照中产生的羟基自由基对毒性去除有限，毒性降低主要由于太阳光的直接光解作用。光照过程中，总有机卤素浓度降低与细胞毒性去除有较好相关性， TOX的降低可能是细胞毒性去除的原因。. 发现UV辐照能显著分解氯消毒再生水中三卤甲烷和二氯乙腈等典型副产物。三维荧光总荧光强度、UV254和SUVA254可作为氯消毒再生水在UV辐照条件下毒性去除的替代性指标。发现相对于单独UV辐照，紫外线/过氧化氢（UV/H2O2）和紫外线/过硫酸盐（UV/PMS）均能促进氯消毒再生水副产物及毒性的去除。