Research On Optimization Method And Application Of Urban Sewage Pipeline Engineering System

Urban sewage pipeline engineering is a keypoint project in people livelihood,one of urban infrastructure related to economic and social sustainable development of the country.The urban sewage will be an immediately,safely,fluently collected and transported to the sewage treatment facilities,and discharged to the region of outflow after purification treatment.It has important practical significance for controling and reducing the investment cost and operation cost of the sewage collection,transportation,disposal and reuse of reclaimed water system from the source of optimization design.It is a complicated system engineering because the pipeline network of urban sewage pipeline engineering is long,and wide in range of distribution,and the rate of flow is large in main pipe of sewage transportation,and the layout of pumping station and sewage treatment plant are influenced by the environment.With the high cost of construction and operation of the sewage collection,transportation,disposal and reuse of reclaimed water engineering,therefore,it has become a focus of concern for investors,an important research topic that scientific research workers need to face how we scientifically and reasonably use the limited funds,and synthetically consider the layout planning of sewage pumping station and sewage treatment plant,the optimization of reclaimed water pumping station and pipeline engineering,and achieve the optimal invesmtent benefit of sewage pipeline engineering system.On the basis of studying and summarzing the theoretical achievements at home and abroad in the engineering optimization of the urban sewage pipeline engineering system,taking the optimization design the urban sewage pipeline engineering system as the research object,taking advantage of the system decomposition aggregation and the orthogonal experimental methods,aiming at the optimization problems of the urban sewage pipeline engineering system,a comprehensive study is carried out,a series of optimization mathematical models are established,the corresponding solution methods are proposed respectively.The main research contents and results are as follows:(1)Under the condition that the laying type of pipe,material,layout and length are known,aiming at optimization design problems of urban sewage collection branch and trunk pipe engineering,a nonlinear mathematical model of optimization design of urban sewage collection branch and trunk pipe engineering is established.The nonlinear model is solved by the large system decomposition-dynamic programming aggregation method.The optimization design mathematical model and the relevant solution method provides a reference for the optimization design problem of the pipe diameter in pipe network engineering of non-full flow.(2)Under the condition that the laying type of pipe,material,layout and length are known,aiming at optimization design problems of urban sewage collection branch,trunk and main pipe engineering,a mathematical model of optimization design of urban sewage collection branch,trunk,main pipe engineering is established with the hydraulic loss at the end of the pipe segment having been set.The nonlinear model is solved by the large system double decomposition-dynamic programming aggregation method.The application research of the optimization method has great practical significance for further enriching and developing the optimization theory of large systems.(3)Aiming at optimization design problem of urban sewage transportation pipe network engineering,a nonlinear mathematical model of optimization design of sewage transportation(no)pressure pipe network engineering is established.For pressure pipe network engineering,the nonlinear model is solved by discrete enumeration and comparison method for design head of pressurized pumping station and one-dimensional dynamic programming for the pipe diameter.For non-pressure pipe network engineering,the mathematical model is solved by one-dimensional dynamic programming.The final design scheme is determined through comparing with the schemes of(no)pressure pipe network engineering,which provides a new method for the optimal design of urban sewage transportation pipe network engineering.(4)Aiming at optimization design problem of urban sewage transportation pressure pipe network engineering with the pumping station layout pending,a nonlinear mathematical model of optimization design of the pumping station and the sewage pipe network engineering is established.The nonlinear mathematical model is solved by large system test selection and subsystem dynamic programming method.The optimal scale of the pressure station and the optimal pipe diameter of the corresponding pipe network engineering can be solved.When the design head level of the pumping station is 0,the problem of the pumping station number and optimal location will be solved.The application research of the optimization method can provide a new approach for the optimal planning of urban drainage pumping station and drainage pipe network.(5)Aiming at optimization design problem of urban sewage treatment plant connected with pumping stations and the sewage pipe network engineering with the sewage treatment plant layout pending,a complex nonlinear mathematical model of sewage treatment plant connected with pumping stations and the sewage pipe network engineering is established.The complex nonlinear mathematical model is solved by applying the two-level orthogonal test of the large system and the dynamic programming method for the pipe diameters method.The optimal layout of sewage treatment plant,including the optimal number and position,the optimal design head of sewage pumping station and the optimal pipe diameter of the corresponding pipe network engineering can be solved,which can provide a reference for the theoretical study of the optimization method of municipal sewage treatment plants planning.(6)Aiming at optimization design problem of reuse of reclaimed water pipe network engineering,a complex nonlinear mathematical model of optimization design of the pressure pumping station and water supply pipe network engineering is established.The complex nonlinear mathematical model is solved by applying discrete enumeration method for design head of pressurized pumping station and large system decomposition-dynamic programming aggregation method for subsystem.The optimal design head of sewage pumping station and the optimal pipe diameter of water supply pipe network engineering will be obtained through comparing with the schemes corrsponding to different design heads of pressure pumping station,which can provide a theoretical reference for the optimization design of urban water supply pipenetwork engineering and pressure pumping station.The analyses of living examples are employed to prove the rationality of the establishedmathematical model and solution methods,and a comprehensive optimization design method and optimization theory has formed for urban sewage pipeline engineering system,which provides theory reference for optimization design of urban drainage water pipe network engineering and urban water supply pipe network engineering.