A large variety of Advanced Oxidation Processes (AOPs) to degrade trace organic compounds during water treatment have been studied on a lab scale in the past. This paper presents the combination of inline electrolytic chlorine generation (ECl2) with low pressure UV reactors (UV/ECl2) in order to allow the operation of a chlorine-based AOP without the need for any chlorine dosing. Lab studies showed that from a Free Available Chlorine (FAC) concentration range between 1 and 18 mg/L produced by ECl2 up to 84% can be photolyzed to form, among others, hydroxyl radicals (OH) with an UV energy input of 0.48 kWh/m3. This ratio could be increased to 97% by doubling the UV energy input to 0.96 kWh/m3 and was constant throughout the tested FAC range. Also the achieved radical yield of 64% did not change along the given FAC concentration range and no dependence between pH 6 and pH 8 could be found, largely simplifying the operation of a pilot scale system in drinking water treatment. Whereas with ECl2 alone only 5% of benzotriazoles could be degraded, the combination with UV improved the degradation to 89%. Similar results were achieved for 4-methylbenzotriazole, 5-methylbenzotriazole and iomeprol. Oxipurinol and gabapentin were readily degraded by ECl2 alone. The trihalomethanes values were maintained below the Germany drinking water standard of 50 µg/L, provided residual chlorine concentrations are kept within the permissible limits. The here presented treatment approach is promising for decentralized treatment application but requires further optimization in order to reduce its energy requirements.

中文翻译：

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通过串联电氯化与紫外线辐射 (UV/ECl2) 相结合氧化选定的痕量有机化合物作为分散式饮用水处理的替代 AOP

过去曾在实验室规模上研究了多种用于在水处理过程中降解痕量有机化合物的高级氧化工艺 (AOP)。本文介绍了在线电解氯生成 (ECl2) 与低压 UV 反应器 (UV/ECl2) 的组合，以便在不需要任何氯剂量的情况下运行基于氯的 AOP。实验室研究表明，从 1 到 18 mg/L 的 ECl2 产生的游离可用氯 (FAC) 浓度范围内，高达 84% 的可光解形成羟基自由基 (OH)，其中紫外线能量输入为 0.48 kWh /立方米。通过将 UV 能量输入加倍至 0.96 kWh/m3，该比率可以增加到 97%，并且在整个 FAC 测试范围内保持恒定。此外，在给定的 FAC 浓度范围内，所达到的 64% 自由基产率没有变化，并且没有发现 pH 6 和 pH 8 之间的依赖性，这在很大程度上简化了饮用水处理中试规模系统的操作。单独使用 ECl2 只能降解 5% 的苯并三唑，而结合使用紫外线将降解提高到 89%。4-甲基苯并三唑、5-甲基苯并三唑和碘美普尔也获得了类似的结果。Oxipurinol 和加巴喷丁很容易被单独的 ECl2 降解。如果残留氯浓度保持在允许范围内，则三卤甲烷值保持在德国饮用水标准 50 µg/L 以下。