Research On Reconstruction Method And Engineering Of Old Water Supply Pipe Network In A Certain City Of Fujian Province For Double Constraints

With the improvement of living standards and increasing number of water consumers,domestic water consumption has drastically risen,and the existing water supply system is crumbling.Take xx city in Fujian province as an example,the current water supply infrastructure was established a long time ago,the number of outdated and deteriorated networks is increasing gradually.High incidence of leakages and bursts resultingfromthese networks has lead to increased running costs and therefore poses an enormous financial burden for enterprises.The current challenge is to guarantee safe water supply without compromising water pressure and quality.The aim of this study is to optimize the current water supply networks to control the incidence of leakages and to reduce the area with insufficient water supply pressure,and thereby to reach the minimum equivalent annual cost by reducing maintenance and running costs.In the example of xx city in Fujian province,the problems in water supply network reconstructions are mainly from three aspects: 1)Missing pipes in the network.2)Increased user density and water consumption.3)Water resource changes.An analysis based on data from historical pipe burst incidences shows that pipe material plays a key role in rupture events with an impact weight of 0.5310.Pipe age and pipe diameter show relatively little influence with impact weights of 0.3078 and 0.1612,respectively.Therefore,the plan for reconstruction considers pipe material as priority but also provides assessments on all three factors.We took equivalent annual costs of network as an objective to perform optimizing analysis.Hydrostatic equation and residual chloride attenuation model were employed as double guidelines to improve the plan for reconstruction.A combination of optimization with static/dynamic data collection and GIS system was used to establish a micro-dynamic simulating system of the network.On this basis,we created a mathematical model under the given restraints of water pressure and water quality to generate solutions for network optimization.We applied the solution in actual reconstruction project and our result showed that overpressure and low-pressure areas in the network decreased while water quality improved.Results also showed that our optimization reduced energy consumption per unit of water and production-sale difference and our expected goal was achieved.