Establishment And Application Of Turbidity Model Of Water Supply Pipe Network Based On Statistical Analysis And EPANET

Water supply network yellow water accident easy to cause a large area of customer complaints,seriously damage the residents' water health and social benefits of water supply enterprises.In the process of quickly solving yellow water accidents,water enterprises have gradually formed the characteristic index of turbidity to judge the yellow water occurrence area and reflect the change of water quality.This project aims to build the turbidities model of water supply network,explore the turbidities change characteristics of the network by using statistical methods,identify the main response indicators that affect the turbidities,build a multi-component water quality simulation model based on the main response indicators,and use the model to carry out the control strategy research on the rapid response to yellow water accidents.Through the analysis of the water quality standard and chemical stability of the pipe network,it is found that the water standard rate of the pipe network in the study area is more than 99.9%,and there is the risk of Fe exceeding the standard and turbidity abnormal fluctuation.The pipe network water has the characteristics of low alkali,low hardness,poor chemical stability and strong corrosion.Through the correlation analysis of water quality indicators,it was found that turbidity had a significant relationship with Fe,total chlorine,oxygen consumption and sulfate response,which was positively correlated with Fe,oxygen consumption and sulfate,and negatively correlated with total chlorine.The quantitative relationships between turbidity and Fe,oxygen consumption,sulfate and total chlorine were constructed by statistical regression and genetic algorithm.By analyzing the sensitivity of its parameters,the absolute value of the sensitivity coefficient of each factor was obtained as follows: Fe,sulfate,total chlorine and oxygen consumption.The EPANET multi-component water quality model was constructed by combining the quantitative relationship of genetic algorithm and the first-order dynamic reaction equation of main response indexes.The model can well simulate the actual phenomenon of steady or rising turbidity,and the simulated value of turbidity in the range of 0?0.35 NTU is in good agreement with the measured value.The model was used to simulate the dynamic change of turbidities of the actual pipe network,and it was found that the fluctuation of Fe content in the factory water had the greatest influence on the turbidities of the pipe network,which was the key control factor for the emergency regulation of yellow water in the pipe network.In order to ensure that the water turbidity of the pipe network is lower than 0.5 NTU,Fe<0.05 mg/L,total chlorine >1 mg/L and oxygen consumption <1.2 mg/L should be controlled.For a yellow water accident,the emergency control measures of the water plant are potassium permanganate 0.3?0.5 mg/L,sodium hypochlorite 0.4?0.5 mg/L,powder activated carbon 30?40 mg/L,coagulation and precipitation pH condition recommended 8.0?8.5.At the same time,emergency drainage and regular pipeline flushing should be adopted for local pipe network at accident nodes.