Risk analysis of disinfection by-products in multi-source drinking water distribution system
YU Ying1,2,, CHEN Ruya1,2, PAN Linlin1,2, HE Yitian1,2, SHI Baoyou1,2,, 1.Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China 2.University of Chinese Academy of Sciences, Beijing 100049, China
Abstract:This study monitored the trihalomethanes (THMs) and halogen acids (HAAs) concentrations of tap water in a large city of northern China with multi-source water supply and analyzed the violation risk, time-space distribution and influencing factors of DBPs. A risk analysis methodology for DBPs in tap water is put forward, which included three aspects, namely, selection of indicative DBPs, monitoring frequency and the layout of sampling points. It was found that the overall risk of DBPs exceeding standard limits in the city is relatively low. However, the risk of HAAs in tap water is significantly higher than that of THMs, thus could serve as an indicator of DBPs in tap water. The areas with relatively high DBPs risks in multi-source DWDS are as follows: areas with mixed water supply from both groundwater and surface water and the far-ends of the pipe network; time periods with water temperature below 20 ℃, dissolved organic carbon (DOC) concentration higher than 1.7 mg·L?1 and free chlorine residual concentration is higher than 0.5 mg·L?1; areas with significant turbidity fluctuation due to unstable hydraulic conditions and the presence of pipe sediments. Sampling frequency and the sampling points should be increased accordingly during the periods/in the areas with relatively high DBPs risk. Key words:multi-source water supply/ disinfection by-products/ sampling frequency/ layout of sampling points.
图1管网采样点分布图 Figure1.Layout of water sampling points
图5温度、DOC、总氯与HAAs质量浓度之间关系及11月管网自由性余氯、化合性余氯的质量浓度分布 Figure5.Relationship between temperature, DOC, total chlorine concentration and HAAs concentration and concentration distribution of free residual chlorine and combined residual chlorine in tap water in November
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1.Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China 2.University of Chinese Academy of Sciences, Beijing 100049, China Received Date: 2020-08-15 Accepted Date: 2020-12-16 Available Online: 2021-05-23 Keywords:multi-source water supply/ disinfection by-products/ sampling frequency/ layout of sampling points Abstract:This study monitored the trihalomethanes (THMs) and halogen acids (HAAs) concentrations of tap water in a large city of northern China with multi-source water supply and analyzed the violation risk, time-space distribution and influencing factors of DBPs. A risk analysis methodology for DBPs in tap water is put forward, which included three aspects, namely, selection of indicative DBPs, monitoring frequency and the layout of sampling points. It was found that the overall risk of DBPs exceeding standard limits in the city is relatively low. However, the risk of HAAs in tap water is significantly higher than that of THMs, thus could serve as an indicator of DBPs in tap water. The areas with relatively high DBPs risks in multi-source DWDS are as follows: areas with mixed water supply from both groundwater and surface water and the far-ends of the pipe network; time periods with water temperature below 20 ℃, dissolved organic carbon (DOC) concentration higher than 1.7 mg·L?1 and free chlorine residual concentration is higher than 0.5 mg·L?1; areas with significant turbidity fluctuation due to unstable hydraulic conditions and the presence of pipe sediments. Sampling frequency and the sampling points should be increased accordingly during the periods/in the areas with relatively high DBPs risk.
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