Investigation of Hydraulic, Technical and Operation performance of Rural water supply Pumping Stations of Ilam province

Access to adequate water and sanitation is one of the basic needs of the rural community. Most of the energy needed to supply, transportation and distribution of rural drinking water is provided by pumping stations. Considering the importance of saving energy, investigation on the efficiency of pumping systems of rural water supply facilities is very important. The efficiency of pumping systems is related to several factors such as: hydraulic, electrical, mechanical, maintenance and management factors. Therefore, it is necessary to evaluate the performance of pumping stations in accordance with the effective factors. Perju and Aldea (2018) studied the upgrade of the pumping stations for an urban water network, to reduce operating, maintenance and water loss costs in distribution networks. The results showed technical solutions within the structural and functional modifications of the pumping stations can lead to both the improvement of hydraulic parameters of the pumping stations and significant energy savings.  This research was conducted to investigate the efficiency of pumping stations of water supply facilities in villages of Ilam province. This province with an area of 20 thousand square kilometers and a population of about 580 thousand people is located in western of Iran. Ilam has a semi-arid climate with an average annual temperature of 21 degrees Celsius and an average rainfall of 480 millimeters. About 30% of the province's population lives in villages with a household size of 3.7. About 99.4% of the rural population of the province is connected to the rural water networks. Pumping stations supplied 81.6% of the total capacity of drinking water. In this province, the consumption of rural water per capita and the water production per capita are 143 and 215 liters per day, respectively. Therefore, water loss is 33.5%. Energy efficiency in pumping stations depends on several factors. For this reason, the evaluation of pumping stations should be systematically reviewed. In general, hydraulic, electrical, mechanical, operation, maintenance, environmental and management conditions affect the operation of pumping stations. Optimal selection of any of the above can be effective in achieving optimal station efficiency. To perform this research the following variables were determined: hydraulic variables (flow velocity, flow rate and pressure), electrical variables (current, voltage, power factor and consumption power), mechanical characteristics (type of pump and electromotor), and geometric characteristics (well depth and pipe diameter). Then, by calculating the power output and consumption power of the electro pumps, the efficiency of each separate station was determined. Using the weighted average method, the average efficiency of the floating electro pumps installed in the water supply system was obtained. The efficiency (η) of each pump can be calculated by the ratio of consumed power (Pc) to the produced power (Pp). Produced power is a function of density (ρ), gravity (g), discharge of pump (Q), and pumping height (H). While, the consumed power (Pc) is related to   voltage (V), electric current intensity (I) and a power coefficient (CosØ) The results of this research indicate that the average efficiency of pumping stations in rural water supply facilities in Ilam province is 61.4%. Among all the selected stations, about 75% of the stations are running with the efficiency of 65.9%. Studies show that the reasons for high efficiency of some pumping stations are the low operating hours of electric pumps, the significant population covered by them and the related social issues. Moreover, about 25% of the flow pumping has the average efficiency of 47.7%. This value of efficiency is relatively low that is mainly related to the pumping stations with low flows. The efficiency of pumping stations is affected by several other factors. Among these factors, the methods of operation, maintenance and management can be mentioned. Installing valves and appropriate equipment on the drift line, Proper placement of transmission lines, avoid making sharp bends and a review of the design of water supply networks, in general, can save a significant amount of energy. Installation of remote control systems, pressure transducers, ultrasonic flowmeters and devices for measuring electrical parameters can make it easier to monitor the operation of the pump station at the optimal point. Consequently in order to increase energy efficiency, it is necessary to review the design of pumping stations, installing performance monitoring equipment at pumping stations, timely repair, regular operation and maintenance, and operators training.