“23·7”特大暴雨情景下供水水源安全监测分析

Monitoring analysis of water supply source safety under the"23.7"extremely heavy rainstorm scenario

2023年7月,受台风“杜苏芮”影响,北京市遭遇连续多日强降雨,导致南水北调环路供水水源由南水切换为本地水源。为保障供水水质安全,采取应急调度处置措施,开展应急水质监测,分析水质变化趋势、水量水质耦合及污染负荷削减情况。结果表明:采取供水应急调度,充分发挥调节池沉淀、稀释作用,调节池出水口浊度、高锰酸盐指数及化学需氧量较来水分别降低90.19%、53.59%和52.93%,水质类别由地表水Ⅲ类提升至Ⅱ类,实现出水口水质满足供水要求目标;高浊度来水与调节池原存蓄水混合,对浊度的影响显著,对电导率、pH值及溶解氧指标影响并不明显;高锰酸盐指数和化学需氧量污染负荷削减率分别为73.49%、78.00%,水质水量联合调度作用得到有效发挥。研究成果为后续应急情况下水质保障提供技术指导。

In July 2023,due to the impact of Typhoon Doksuri,Beijing suffered from continuous heavy rainfall for several days,resulting in the South-to-North Water Diversion Ring Pipeline water supply source being switched from South-to-North water to local water source.To ensure the safety of water supply quality,emergency dispatch and disposal measures are taken,emergency water quality monitoring is carried out,and the trend of water quality changes,coupling of water quantity and quality,and reduction of pollution load are analyzed.The results showed that adopting water supply line 4 for emergency dispatch,fully utilizing the sedimentation and dilution effects of the regulating tank,the turbidity at the outlet of the regulating tank decreased by 90.19%compared to the incoming water,the permanganate index decreased by 53.59%,the chemical oxygen demand decreased by 52.93%,and the water quality category was upgraded from surface water category III to category II.The water quality was effectively improved,and the water quality at the outlet met the water supply requirements;The high turbidity incoming water is mixed with the original storage water in the regulating tank,and the improvement effect of water quality through sedimentation and dilution in the regulating tank is more significant than that of pure water mixing.Among them,the impact on turbidity is greater,and the impact on conductivity,pH,and dissolved oxygen indicators is not significant;The potassium permanganate index and chemical oxygen demand pollution load reduction rate were 73.49%and 78.00%,respectively,indicating a significant reduction in pollution load.The joint regulation of water quality and quantity was effectively utilized.The research results provide guidance for ensuring water quality in subsequent emergency situations.