The Study Of There Claimedwater Pipelins Characteristics And The System Stability Analysis

The use of reclaimed water has been promoted by the government during theTwelfth Five-Year plan period vigorously. As one of the key parts, there is no doubtthat the construction of the reclaimed water distribution network will be in a veryimportant position. Since the reclaimed water sources, water quality, the users as wellas its distributed requirements are quite different with the tap water, there haveobviously characteristics from its planning to construction and operating management.Therefore, specialized theoretical and experimental research as well as the practicalexperience must be put forward to find a suitable technology and management wayswhich consistent with its characteristics. These results will have a strong urgency andpractical significance for the construction of reclaimed water network with a highquality and durable security operation to protect regeneration, and it also related to theoverall goal of reclaimed water used be successfully achieved.Currently, the development of reclaimed water supply network varies greatly.The targeted technical standards are not perfect; some of the problems found in theactual operation also need to be searched a solution thought some specialized research.In this study, begin with the current situation of renewable water supply network; usethe analytical and experimental research laboratories and combine of practical methodengineering research. Therefore the reclaimed water pipeline network characteristicsand stability were researched, from both theoretical and practical aspects.First, through the collection of data, field research and expert advice and otherways, the domestic actual project operating experience were analyzed andsummarized. And reclaimed water distribution system design and operational featureswere proposed to direct pipeline construction and operation management in the future.Secondly, for the reclaimed water quality characteristics choose the greaterimpact safety problem on reclaimed water distribution that reclaimed water qualitychanges in the distribution pipeline and the tendency of different types of renewablewater pipes by corrosion of water quality impacts in the laboratory, a series of testsresearch were conducted.First select a common PE pipe, PVC-U pipes and nodular cast iron pipes andother pipes, the use of test equipment designed for different processes to producereclaimed water tested. The results showed that: It is not change in PE, PVC-U tubesthat regular process and membrane process of reclaimed water in the water, It meansmaterial PE, PVC-U tubes and mass exchange between the reclaimed water does notoccur, reclaimed water stability in this kind of pipe. Conventional process ofreclaimed water in the cement lining of nodular cast iron pipe, reclaimed waterhardness and alkalinity is decrease, showing scaling tendency. Membrane technology of reclaimed water in the cement lining of nodular cast iron pipe, pH from7.09to7.09within10h, beyond the basic standard of reclaimed water is6.5~9.0, hardnessand alkalinity in50h change respectively is27.59mg/L,53.57mg/L, silicon dioxideby0mg/L to11.82mg/L, cement lining in the calcium silicate and calcium carbonatedissolved in the water, ductile iron pipe coating and lining of cement.Then, using a standard degree rotation test coupon weight loss method, theresearch on corrosion degree of reclaimed water which produced by membraneprocess and conventional process respectively on A3carbon steel, gray iron andnodular cast iron were tested, then it also be compared with the tap water.Experimental results have showed that A3carbon steel has the strongest capacity inthe corrosion resistance within the three types materials, the beginning corrosion rateof three kinds of pipe material with the conventional process reclaimed water is fasterthan later period, less tend to be stable over time, the membrane technology reclaimedwater corrosion rate is small at the beginning of, fluctuation and change trend overtime. Through orthogonal experiment, five water quality parameters which supposedto be influence on the pipe materials corrosion were analysis. The experimental resultsshowed that the SO42-were displayed to promote corrosion effect on three kinds ofmaterials, and corrosion products form change at concentration of60~120mg/L; Cl-also has promoting effect of corrosion on the three kinds of material, when theconcentration of90~120mg/L, appeared trends by surface corrosion to corrosion;Three kinds of materials in the corrosion rate decreased with increasing alkalinity inthe water, and the hardness of grey cast iron and ductile iron corrosion inhibition.Through the analysis of corrosion behavior is similar on grey cast iron and nodularcast iron. Using LSI and LR index to judge the water quality of A3carbon steel, grayiron and nodular cast iron corrosion, the applicable type of water quality need to beconsidered.