A New Approach to the Optimal Design of a Reclaimed Urban Water Reuse System

It is strategically important to optimize the pipe network used for reclaimed urban water reuse. A large and complex system model is developed, with the minimum total annual cost of the pumping station and pipe engineering as objective functions, the head loss in the divided pipe segment as the coupling constraint, the economic flow velocity and the optimal diameter of a standard pipe as feasible domain constraints, and the design head and diameter of the pipe as decision variables. The problem is solved by combining the ratio of the discrete enumeration of the design head to the decomposition-dynamic programming aggregation of the large-scale system. This strategy can solve the problem of the optimal pipe diameter in each section of the pipe network engineering under a fixed design head of the pressurized pumping station. On this basis, the annual cost of reclaimed water reuse pipe network engineering is compared under the different design heads of the pressurized pumping stations, allowing the optimal design scheme for reclaimed water reuse pipe network engineering to be obtained. At the same time, the optimal design head of the pressurized pumping station and the optimal pipe diameter of each section can be identified. This can provide a theoretical reference for the optimal design of urban and rural water pipe networks.