污水二级出水水质对臭氧深度处理去除药物和个人护理品的影响及机理研究

Due to the poor treatment performance by secondary biological processes, most pharmaceutical and personal care products (PPCPs) are released to the water environment continuously from wastewater treatment plants, and induce adverse effects to the environment. Ozonation, as a tertiary wastewater treatment process, is efficient to remove most PPCPs; however, fluctuation of the biological treated effluent can adversely affect the stability of the ozonation processes, leading to unacceptable removal performances of PPCPs. The effects of secondary effluent quality on the removal performances of PPCPs have been studied in the latest researches. However, most of them are assessed by chemical indicators, such as PPCPs concentrations and total organic carbon (TOC), and very few of them focused on bioassays, which reflected the comprehensive environmental risk. Furthermore, to the best of the knowledge, the mechanisms of the effects on the removal performance were seldom reported at present. With this regard, in this study, both chemical analysis and bioassays (including acute toxicity test and chronic toxicity test) will be employed to study the effects of secondary effluent quality on the removal efficiency of PPCPs by ozonation. Furthermore, in order to elucidate the mechanisms of the effects, radical probe compounds will be introduced, and the oxidation products under different situations will be identified. The results obtained will be helpful for further theoretical study and aslo provide necessary information on the application of ozonation to the removal of PPCPs.

传统的二级污水处理工艺对大多数药物与个人护理品（PPCPs）的去除效果有限，使其随出水持续排放进入水环境，威胁生态环境安全。臭氧氧化作为一种污水深度处理工艺，能有效去除大多数PPCPs，但受二级出水水质变化等影响，去除效果存在较大波动。现有研究大多从化学分析角度（PPCPs浓度、总有机碳变化等）出发，揭示二级出水水质对PPCPs去除效果的影响，较少从生物毒性角度入手，综合评价去除效果的波动可能导致的环境风险，而对于出水水质影响PPCPs去除效果的内在原因更是非常缺乏。因此，本项目拟同时采用化学分析与生物毒性分析（包括急性毒性和慢性毒性分析）手段，系统研究二级出水水质对臭氧深度处理去除PPCPs的影响，在此基础上，开展自由基探针试验，识别氧化中间产物并探索其生成规律，解析水质影响臭氧深度处理PPCPs的机理，为提高臭氧深度处理去除PPCPs的效率与稳定性提供理论指导与技术支持。

臭氧氧化是一种能有效去除大多数药物和个人护理品（PPCPs）的污水深度处理技术，但其去除效果存在波动。. 本项目通过对实际污水处理厂的长期监测分析和小试规模的验证试验，发现水质波动是导致臭氧深度处理工艺对药物和个人护理品（PPCPs）去除效果波动的主要原因。在此基础上，分别从目标化合物浓度变化、总有机碳变化和急性毒性变化三方面出发，系统考察了pH值、碳酸盐/碳酸氢盐和三种模型出水有机物（多糖、蛋白质和腐殖酸）对臭氧氧化两种典型PPCPs苯扎贝特（BF）和舒必利（SP）的影响。. 开展了BF和SP的臭氧氧化动力学研究，其中SP与臭氧分子和羟基自由基的反应动力学常数填补了相关研究的空白。基于动力学研究结果，开展自由基探针实验，定量考察了不同条件下羟基自由基与臭氧氧化的氧化贡献，验证了羟基自由基和臭氧分子氧化贡献的差异是水质条件影响BF和SP臭氧氧化的主要机制。. 利用高分辨液相色谱-质谱联用仪，解析了BF的臭氧氧化产物和氧化途径；并通过基于QSAR的中间产物毒性预测、中间产物浓度变化和急性毒性变化的一致性等条件，首次识别出BF臭氧氧化初期（急性毒性显著升高阶段）可能的致毒中间产物。. 在本项目的资助下，共发表学术论文16篇，其中SCI论文4篇，培养博士研究生1名，硕士研究生2名。研究结果在综合考虑臭氧深度处理工艺去除目标化合物和降低生态风险、提高回用水的安全性方面具有重要的参考价值，在阐释水质影响臭氧深度处理PPCPs的机理方面具有创新性。