Water Quality Stabilization And Water Quality Simulation Of Water Distribution System

In order that the hydraulic simulation and water quality simulation of water distribution system can be more practical so as to timely and effectively understand its hydraulic and water quality condition, and that the daily management, optimal dispatch and water quality stabilization and control of water distribution system is convenient, it is important to estimate the states and parameters of whole water distribution system by using node pressure of monitoring points of water distribution system, residual chlorine content, link flow rates, total water supply amount of water plant, Hazen-Williams Coefficient of some pipelines from field measurement, residual chlorine decay efficient of bulk water and residual chlorine decay efficient of pipe wall.In this thesis, two models respectively for state and parameter estimation of water distribution system, and parameter estimation of water quality model, which are the minimum problems, were built based on the principle of the least square method, that is to say the sum of squares of the differences of estimated node pressure, link flow rates, water supply amount of water plant by state and parameter estimation of water distribution system between actual measured pressure, link flow raters, water supply amount of water plant should be minimum, and the sum of squares of the differences of the estimated residual chlorine content by parameter estimation of water quality model between actually measured residual chlorine content should be minimum. The steps and program realization method to solve the two models by using Steady State GA was further discussed. The two models were applied to the example pipeline network. The error between estimated node pressure and actual node pressure is controlled under 5%, the error of estimated link flow rate and actual link flow rates is 2.04%, and the error between estimated flow rate and actually measured flow rate is 2.27%,3.14%, respectively. The water quality simulation sets 5 monitoring points, and the RSS between estimated residual chlorine concentration and actually measured concentration is controlled under 0.0014mg/L, which suggests that the two models are correct and feasible, that solution method adopted is of excellent accuracy and relatively fast convergence rate , and that the two models can fully satisfy the accuracy demand of real-time hydraulic and water quality simulation of water distribution system.On the above basis, water quality simulation of water distribution system was carried out; water quality distribution condition was analyzed; against that the local residual chlorine content level would be too low and intentional contamination intrusion to water distribution systems, the Maximal Covering Location was used to study optimal location of chlorine's adding positions in area that residual chlorine content is too low, and supplementary optimal location of monitoring points against intentional contamination intrusion to water distribution systems; and the optimal location models were built correspondingly. Simulation calculation result showed that chlorine's adding positions and water quality monitoring points arranged by the above two optimal location models showed a reasonable distribution, and can effectively maintain stabilization of water quality of water distribution system and quickly get a feedback of variation of water quality.