Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of the Chinese Academy of Sciences, Beijing 100019, China.
Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of the Chinese Academy of Sciences, Beijing 100019, China.
Water Res. 2017 Mar 15;111:147-153. doi: 10.1016/j.watres.2016.12.043. Epub 2016 Dec 27.
Despite the strong oxidizing ability of ozone, pre-ozonation has seldom been employed for the purpose of micropollutant removal in drinking water utilities. In this paper, the possibility of using pre-ozonation instead of post-ozonation for the removal of micropollutants was explored because of the lower risk of forming carcinogenic bromate. A 1.0 m/h pilot system was utilized to compare the efficacy of pre- and post-ozonation in the removal of bulk organic pollutants as well as micropollutants, including typical odor-causing compounds, pharmaceuticals, and typical pesticides, from one source water (Huangpu River) characterized by the occurrence of various micropollutants. Both pre-ozonation and post-ozonation could achieve similar water purification performance under an ozone dose of 1.5 mg/L, in terms of bulk water quality parameters like COD (66% in combination with biological activated carbon (BAC) treatment, compared to 62% with the pre-ozonation-BAC combination) or micropollutants including 27 pharmaceuticals (85% in combination with BAC compared to 87% with the pre-ozonation-BAC combination) and 25 pesticides (72% in combination with BAC compared to 61% with the pre-ozonation-BAC combination). Pre-ozonation exhibited slightly better odorant removal performance (100% in combination with BAC compared to 92% with the post-ozonation-BAC combination); however, post-ozonation generated approximately 6.0 μg/L bromate at an ozone dose of 2.0 mg/L, while pre-ozonation did not form bromate even at an ozone dose as high as 3.0 mg/L. So pre-ozonation in combination with BAC might be a solution for the removal of micropollutants from source water with high bromate formation risk. The results of this study will be helpful for the optimization of ozonation processes in the water supply industry.
尽管臭氧具有很强的氧化能力，但在饮用水处理厂中，预臭氧化很少用于去除微量污染物。本文探讨了利用预臭氧化代替后臭氧化去除微量污染物的可能性，因为其形成致癌溴酸盐的风险较低。利用 1.0 m/h 的中试系统，比较了预臭氧化和后臭氧化在去除大宗有机污染物以及微量污染物（包括典型的致嗅化合物、药物和典型的农药）方面的效果，原水为黄浦江水源，存在各种微量污染物。在臭氧剂量为 1.5 mg/L 时，预臭氧化和后臭氧化都可以达到相似的净水效果，就水质参数而言，如 COD（组合生物活性炭（BAC）处理后为 66%，而预臭氧化-BAC 组合后为 62%）或微量污染物，包括 27 种药物（组合 BAC 处理后为 85%，而预臭氧化-BAC 组合后为 87%）和 25 种农药（组合 BAC 处理后为 72%，而预臭氧化-BAC 组合后为 61%）。预臭氧化对嗅味物质的去除效果略好（组合 BAC 处理后为 100%，而后臭氧化-BAC 组合后为 92%）；然而，在后臭氧化中，在臭氧剂量为 2.0 mg/L 时，溴酸盐生成约 6.0 μg/L，而在臭氧剂量高达 3.0 mg/L 时，预臭氧化并未形成溴酸盐。因此，预臭氧化结合 BAC 可能是一种从高溴酸盐形成风险的原水中去除微量污染物的解决方案。本研究结果将有助于优化供水行业的臭氧处理工艺。
