基于微滤技术供水厂的臭氧预氧化前置工艺中臭氧投加量的优化

通过臭氧预氧化降解水体中溶解性有机物(DOM)对DOM的氧化效果以及微滤(MF)膜污染的缓和效应进行了研究，并分析了臭氧氧化过程中光谱参数变化的规律，进而提出一种通过多目标优化模型确定最佳臭氧投加量的方法。结果表明，臭氧预氧化技术能够将中等分子质量的芳香类DOM转化为低分子质量的有机化合物，对应的UV₂₅₄去除率最高可达90.34%，从而显著改变了MF进水的光谱特性。此外，臭氧预氧化还显著缓解了DOM造成的膜污染，膜污染指数(FI)最多可降低51.49%。根据上述结果可建立多目标优化模型，并用于确定臭氧预氧化-膜过滤工艺最佳臭氧投加量。根据层次分析法，对SUVA₂₅₄、FI和臭氧利用率3个客观指标分配不同的权重，以满足不同饮用水厂的需求。此外，模型分析中可用光谱斜率作为SUVA₂₅₄的替代参数，特别是S_275~295 (R²=0.979 7)，用UV₂₅₄作为FI的替代参数(R²=0.879 9)，进而简化模型系数的获取。以上研究结果可为水厂在实际应用中优化臭氧投加量、综合提高水处理效果、缓解膜污染并降低运行成本提供参考。

Optimization of ozone dosage in the pre-oxidation process of water treatment plants with microfiltration technology

Through ozone pre-oxidation to degrade dissolved organic matter (DOM) in water, the efficiency of pre-ozonation for dissolved organic matter (DOM) removal and membrane fouling control were studied, and the variations in the UV-vis spectra of the treated water were analyzed. Furthermore, a multi-objective optimization model was proposed for identifying the optimal ozone doses for pre-oxidation. The results showed that pre-ozonation could transform aromatic DOM with medium molecular weight into small organics, the corresponding UV254 removal efficiencies could not exceed 90.34%, which significantly changed the spectral characteristics of the feedwater to the membrane filter. Moreover, pre-ozonation noticeably mitigated membrane fouling by DOM, and the fouling index (FI) decreased by no higher than 51.49%. Accordingly, the simplified multi-objective optimization model was developed to identify suitable ozone dosing for the integrated ozonation pre-oxidation -microfiltration process. Different weights were assigned to three objective factors, i.e., SUVA254, FI, and ozone utilization ratio through the analytic hierarchy process, to account for the diverse needs of drinking water treatment plants (DWTPs). To further simplify instrumental requirements, SUVA254 used in the model may be replaced with the spectral slope parameters, especially S275~295 (R2=0.979 7), and FI may be replaced with UV254 (R2=0.879 9). These findings provided useful guidance for DWTPs to optimize ozone dosage, comprehensively improve DOM removal, mitigate membrane fouling, and reduce operational costs.