Optimal Performance-Based Design of Wastewater Collection Systems

Wastewater collection systems play key role in servicing the public and protecting the environment. Construction of these facilities is expensive and needs large investments. Therefore optimization of sewer network construction costs will have an essential effect on early implementation of these plans all over the country. On the other hand, reviewing the experiments of developed countries in the field of maintenance and operation of the sewer networks represents that reducing the maintenance and operation costs is necessary as well as optimizing the construction costs, so designing a sewer network with high reliability and proper performance which is able to transport wastewater without hydraulic overload should be considered. In this study a methodology is developed to optimize sanitary sewer systems with object of minimizing network construction and operation costs and considering system reliability as an optimization constraint by Genetic Algorithm method. For this reason a definition for wastewater collection system reliability has been provided and its applicability has been analyzed by some system performance indicators. The Efficiency of the proposed methodology has been assessed in a case study. It is also observed that with considering reliability and hydraulic performance indicators as optimization constraints, a more reliable collection system with less environmental impacts will be achieved by a reasonable increase in construction costs.