Scheduling and operating costs in water distribution networks

This paper aims to assess the reduction in level of leakage and excess pressure in water distribution networks (WDNs) after imposing a schedule to a pumping station. This is of particular importance where managers, due to financial considerations, may be forced to construct WDNs that are directly connected to water resources. In such WDNs there is no tank, leading to unreasonable water loss and excess pressure in the WDN. Also, in such circumstances, the size of the search space is reduced so that no need is felt to use optimisation algorithms to find the optimal pumping schedule. In this study, the pumping schedule was obtained for two real WDNs in Iran, using single-speed pumps and variable-speed pumps. The results showed that through smart scheduling energy cost savings can be up to 24%, and the existing leakage and excess pressure can be reduced by 11% and 53%, respectively. It was noted that an increase in the number of pumps could improve the amount of savings made. Finally, it was demonstrated that the pumping schedule obtained by the method suggested in this study was optimal and can still be functional when the demand pattern varies stochastically.