Analysis and Quality Management of Water Distribution Networks Under pollution intrusion in the Situation of Water Pressure Reduction (Case Study: Zahedan water Distribution Network)

Pollution entrance into water resources systems, such as urban drinking water distribution networks, can cause irreparable damage to human health as a result of the suction phenomenon.Awareness and understanding of pollutant sources and transport of contamination process in the water network cause suitable modeling of this phenomenon as well as perform a proper crisis management when the contaminants enter the network. In order to simulate the movement of nitrate in the soil, the nitrate advection-dispersion equation was programmed in MATLAB. Zahedan drinking water distribution network has been considered as the study area and potential points with high concentration of pollutants in the network have been identified. Scenario of 24-hour water network simulation, after two hours of contamination, was tested for water contamination by using WATERGEMS, EPANET and EPANET-BAM software., to manage the network pollution crisis, two tools were proposed including detention time and dilution flow. To calculate detention time, the network was divided into four parts including: near, middle, far and very far. The results demonstrated that nitrate concentration near the pipe is unallowable and greater than 50 mg/l and required detention time to treat the quality of water in the nodes of the middle, far and very far decreased 33 to 50, 58 to 62.5 and 75 percent compared to the near nodes, respectively. Moreover, efficiency and positive performance of dilution flow as a tool for quality management was proved. Required dilution flow to treat the quality water was determined from 10.6 to 15.9% of the base pipe flow.