长江干流铜陵段突发水污染情景模拟分析

Scenario simulation analysis of abrupt water pollution in Tongling section of the mainstream of the Yangtze River

突发水环境事件情景模拟分析对风险防控与应急处置至关重要。在对铜陵市沿江化工企业风险物质泄漏情景分析的基础上,采用MIKE21二维水动力-水质耦合模型对长江干流铜陵段突发水污染事故进行了模拟。模型验证结果表明,构建的水动力模型满足精度要求。对某化工企业储罐3种泄漏情景下的模拟结果表明:同一水文期,风险物质对下游敏感受体的污染程度和污染时间主要与泄漏总量有关,储罐完全泄漏情景对下游敏感受体影响最大,其最大污染峰团浓度高于罐体20%管径破裂和罐体100%管径破裂泄漏情景2~3个数量级;不同水文期,泄漏物质在丰水期到达下游敏感受体的时间最短,储罐完全泄漏时风险物质到达下游三水厂取水口用时75 min,而在平水期和枯水期分别为103和111 min,同时影响时间更长、浓度更高,下游五水厂取水口和铜陵市出境断面在平水期和枯水期先后有2次污染峰团到达。

Scenario simulation analysis of abrupt water pollution is important for risk prevention and control and emergency response.Based on the analysis of risky substance leakage scenarios of chemical enterprises,MIKE21,a two-dimensional hydrodynamic-water quality coupling model,was used to simulate the abrupt water pollution accident in the Tongling section of the mainstream of the Yangtze River.The model verification showed the constructed hydrodynamic model could meet the accuracy requirements.The simulation results of three different leakage scenarios for one chemical company's storage tank showed that:in the same hydrological period,the pollution degree and time of risky substances to downstream sensitive receptors were mainly related to the total amount of leakage,and it had the most serious impact on downstream sensitive receptors when the storage tank was leaked entirely,and the maximum pollution peak was 2~3 orders of magnitude higher than 20%and 100%pipe diameter leakage.In different hydrological periods,risk substances took the shortest time to get to downstream sensitive receptors in the wet period,and it took 75 min for the risky material to reach the water intake of the Third Water Plant when the storage tank was leaked completely;but it took 103 min and 111 min during the normal and dry periods,respectively,and the impact time was longer and the concentration was higher.And there were two pollution peaks successively at the water intake of the downstream plant and the outbound section of the city in the normal and dry periods.