Study On Water Quality Change In Drinking Water Transportation

Drinking water disinfection methods include chlorination disinfection,ozone disinfection and ultraviolet disinfection.However,chlorination disinfection is still a major water at home and abroad due to the low cost,simple operation,convenient management and the effect of preventing secondary pollution of water body.But the concentration of residual chlorine in water body is affected by different factors,the bacteria in water body will also be affected by disinfection technology and other factors,and the disinfection by-products will be produced by reaction with water body in the process of chlorination disinfection.Therefore,the decay law of residual chlorine in water body,the number of bacteria and the disinfection by-products will be studied in the process of chlorination disinfection.The factors affecting the generation of disinfection by-products are of great significance.Firstly,the decay law of residual chlorine in water was studied,and the effect of different influencing factors on the change of residual chlorine was analyzed.The decay law of residual chlorine in water was explored by first-order dynamic model.The decay of residual chlorine in water can be divided into two stages(0~2h,2H~50h).The model of residual chlorine concentration in water can be well established by first-order kinetic model,and the fitting correlation is high,and the relevant parameters can be obtained by fitting curve.The decay of residual chlorine in different water temperatures(5?,15? and 25?)was analyzed.With the increase of water temperature,the consumption rate of chlorine in water was gradually accelerated and the decay coefficient of residual chlorine was also increasing.TOC was used as the evaluation index of organic matter content in water to explore the decay of residual chlorine in different organic matter content.With the increase of TOC concentration,the consumption rate of chlorine in water is gradually accelerated.The results show that organic matter in water can react with chlorine and accelerate the consumption of chlorine.The effects of different factors(initial chlorine concentration,temperature,pH value and ammonia nitrogen content)on the formation of trihalomethane were further studied.The results showed that the chlorine in the water was quickly depleted when the concentration of [Cl]/[TOC]<0.3,and the formation of trihalomethane was less;when the concentration of [Cl]/[TOC]<1.6,the formation of trihalomethane in the water was positively correlated with the decay of residual chlorine;when theconcentration of [Cl]/[TOC]>1.6,the content of trihalomethane increased slowly.Under the same conditions,the higher the water temperature,the more trihalomethane produced by chlorination disinfection;the pH value of water has a significant impact on the formation of trihalomethane,with the increase of water pH value,the content of trihalomethane gradually increased,and the formation of trihalomethane in alkaline water than in acidic and neutral conditions.With the increase of ammonia nitrogen concentration,the content of trihalomethane in water decreased,indicating a negative correlation between the two.Finally,this paper studies the water quality of the actual water supply pipeline in the urban area.The results show that in the first quarter,due to the lower environmental temperature,the residual chlorine decays slowly,and the residual chlorine concentration in each region is higher;the number of bacteria in the water samples collected from different regions is different;and the trihalogenate in the water body of each detection point is different.The concentration of alkane varied from 47 to 120?g/L,and the overall fluctuation amplitude between different detection points was large,showing a high concentration in summer and a low concentration in winter.