Modeling energy losses in the hydraulic system of Vombverket water treatment plant / Modellering av energiförluster i Vombverkets hydrauliska system

Vombverket, one of the major water treatment plants in south Sweden, originally built in the 1950’s, was significantly expanded in the 1990’s. Because of this expansion, the water flow path was prolonged. The plant was not optimized for the new process design with regard to the hydraulic conditions, but substantial pressure losses were introduced through the addition of bends, valves, and other hydraulic components. In order to increase the capacity of the system, pumping has been considered; however, an alternative to this measure is to eliminate some of the added energy losses. The locations and properties of these losses should be established by performing a detailed analysis of the hydraulic system for a range of different flow conditions. The present study started with a literature review on energy losses in hydraulic systems, followed by a thorough investigation of the existing system based on available drawings and other material. The hydraulic system was schematized to yield a simplified conceptual model, which included components with significant influence on the losses of the system. Measurements of the pressure and flow rate were carried out at selected points in the hydraulic system in order to quantify the losses. A hydraulic model was developed, and available measurements were used for calibration and verification. Different modifications to the hydraulic system were simulated for a range of operational conditions. In the model simulations, the plant was divided into three sections comprising the filter buildings 1, 2 and 3, each encompassing a series of hydraulic components. Two types of modifications to the system were shown to be favorable; (1) remove the two weirs and the Venturi meters in filtration building 1 and 2 and one gate valve in building 1; and (2) directly connect the hydraulic system in filtration building 1 and 2 to the downstream reservoir, thus shortening the water flow path and reducing energy losses.