The South To North Water Diversion Project Water Source Of Raw Water Impact On Beijing Water Supply Network And Control Technology

With the expansion of urban scale and population growth, water resources have become the key factors which restrict the development of the city. The South-to-North Water Diversion Project in China is the largest of its kind ever undertaken. The project involves drawing water from southern rivers and supplying it to the dry north. After this massive scheme finised, water supply reliability of Beijing city will be enhanced, and more water source types, but water source change may bring water emergencies, the risk is still great. The biggest risk in water quality controlis water quality safety and emergency disposal. In this paper, it is analyzed that the Beijing city water supply network system and the present situation of water quality, and "yellow water" in water network studied. The internal coating resin technology and chlorination boostering method is presented according to the mechanism, causes, influence factors and control technology of "yellow water" control.The mechanism of "yellow water" in pipe network is studied under the condition of water source switched for the South-to-North Water Diversion Project: The yellow drinking water is not evenly distributed in the network area, where drinking water is from the south to North Water Diversion Project. It is presented the obvious characteristics of regional distribution according to yellow water distribution. The corrosion rate of iron pipe line and LR value are positive correlation. The structure and composition of pipe scale is associated with water quality. From the SEX-EDX, it can be clearly see that there are different forms of Iron oxide in the nodular scale typical hierarchical structure, we can determine the accurate type of the Iron oxide through its microstructure what we get from the sample spectrum analysis results in combination with the XRD quantitative analysis results of the samples. The concentration of SO32- in the surface water is higher than that in the groundwater. That made the consequence that the corrosion degree in surface water pipe is high and the scale layer is very thick. It will be suitable for the survival of sulfate reducing bacteria. The sulfur will exist in surface water by the form of SO priority and that in groundwater by the elemental sulfur.The water network model and AR reactor is built in this paper. The raw water for pipeline corrosion simulation test is from the ninth water plant in Beijing. The corrosion test of field pipeline in water supply network in Beijing is also used.When the Danjiangkou reservoir water is used, the corrosion products in different areas of water network in Beijing city is studied using the Danjiangkou network test base. We can see that the concentration of iron is reduced gradually. Through contracting the standard of surface water and the reservoir water, we can fine that it will relate to the concentration of the PH, alkalinity, SO42-, Cl- and DO and the network tend to stabilized will make the LR amplitude of variation higher. The model of Siderite can be used to analysis network in the formation process of the corrosion products and pipe network water quality in the water quality changes.The results show that, the corrosion rate of pipeline network will increase as the temperature getting high. It will peak in the summer. The concentration of iron is affected by the PH which too high or too low will make the rate of Iron oxide compounds precipitate get faster. It will be affected by the operation management way as well. The batch-type water supply will get the corrosion of iron faster the continuous system. We can control the “yellow water” in the network by controlling the corrosion of iron. Controlling the PH of water or taking some phosphate which can reduce the quantity of bacterial in water can be effect on controlling the “yellow water”.Pipeline spraying technology is in favor of maintaining iron instability in the water supply network, and can be applied to "yellow water" control in water network. The combined use of chlorine and chlorine dioxide disinfectant has a certain coupling effect, and disinfection effect is continuously enhanced in the same disinfectant concentration. It has a positive role to reduce the occurrence of "yellow water" in water network.