Gravity Wastewater Collection Systems Optimization

A computer algorithm for the selection of optimal depth‐diameter combinations for all links of a complete gravity wastewater collection system has been developed using dynamic programming. The algorithm incorporates two subprocesses P1 and P2. The subprocesses P1 generates all feasible designs of inflowing lines at a junction manhole whereas P1 uses these feasible designs to provide the upstream invert level of the outflow line, simultaneously solving the matching problem encountered at each junction manhole. The problem of dimensionality has been minimized by exploiting the characteristic features of wastewater collection system. The optimal design for a 10.7 km long collection system at Indian Institute of Technology, Bombay with 52 lines, 245 links, 224 ordinary manholes and 21 junction manholes has been compared with conventional design to bring out that the algorithm requires small computer memory, small execution time and leads to optimal solution of a complete gravity wastewater collection system.