Optimal water supply pump operation considering disinfection performance

As of 2013, 86.5 % (5,076 GWh) of the annual electricity consumption incurred by waterworks in Korea was for power such as water supply and intake pump operation [1]. Thus it can be inferred that most of the energy and budget involved in current waterworks are spent for power, that is, to operate such mechanical equipment as pumps. Water supply pump operation costs have been influenced by seasonal and hourly differential power prices. This means that pump schedule optimization would enable water supplier to provide consumers with the water supply service that meets their demand, while also gaining the effect of reducing operation costs. Water quality is also important in water supply system as much as quantity. Accordingly, this research aimed to develop an optimal water supply pump scheduling scheme that considers quantity and water quality. In order to achieve the aim, pump efficiency was measured using a thermodynamic method, so as to check the current performance of the water supply pump and then to apply the result to pump scheduling. Further, 2 optimal water supply pump scheduling schemes-one based on genetic algorithm(GA), and the other based on dynamic programming(DP)-were respectively developed. Also the actual water supply pump operation schedule was compared with the optimal water supply pump schedules using genetic algorithm deduced for a period of 14 days in summer and winter. As a result, The expected annual saving for the year calculated by applying average daily saving for winter is about 230 million KRW (209,091 USD). And all the optimal pump operation ensured sufficient residence time of the disinfectant.