Study On Identification Of Sudden Contamination Accident And Rapid Isolation Of Contamination In Water Supply System

In recent years, sudden contamination accident in urban water supply system hasan increasing tendency. Once the sudden contamination accident occurs in thelarge-scale urban water supply system which has multiple sources interconnection andinterflow, the contamination would be easily spread and form a global risk, but theemergency response system to sudden contamination accident was still not perfect.Aimed at this situation and based on EPANET, emergency response system wasstudied in this research, which included rapid isolation technology and identificationof sudden contamination accident.Firstly, the probability of contamination accident being monitored was defined.A double-objective optimization location selection model was established aiming atminimizing the flow of contaminated water and maximizing the probability ofcontamination accident being monitored; Besides, taking the actual pipe network asan example, the Pareto optimal solution was obtained by weight coefficient methodwhich was mainly applied in solving multi-objective optimization issue.Secondly, a step by step location-determine model for contamination source wasproposed. The model was carried out in three steps. The simulation on nodes withinthe monitoring range of the monitoring point whose water quality was abnormal wereconducted. The potential contamination source could be found by comparing thesimulation results with the actual monitoring data. The abnormal water quality datamonitored in the next moment (second moment) were used to simulate the potentialcontamination source then. The new contamination source would be more inaccordance with the monitor data in the second moment. The only contaminationsource was conformed finally after several simulations. The model was validatedwith the example of the actual network.Finally, in view of the sudden contamination accident in urban water supplysystem, rapid isolation technology was put forward based on valve control, schedulingoptimization of waterworks and emergency discharge of the pipe wastewater. Thevalve closing algorithm based on breadth-first traversal search was proposed. In orderto ensure the water hydraulic requirements in unpolluted areas after closing the valve,the model for scheduling optimization of waterworks was established, while the actualnetwork example was solved by the use of Matlab GA toolbox. Besides, in order to discharge the contamination, the commonly used methods of discharging thewastewater in the pipe network were introduced. The formulation process of flushingplan of the pipe in the pipe network were described in detail at last.These results demonstrated that the research could be used to identify and dealwith the sudden contamination accident rapidly, to minimize the influence scope andextent, and restore normal water supply as soon as possible.