Determination of number of booster stations considered by quality constraints in drinking water networks and evaluation in view of costs

Water is one of the most important elements in the world for the survival of life and vitality. Despite the increasing technological capabilities, the pressure on the water resources is increasing because of climate changing, rapid urbanization, increasing population and industrialization reasons. The most important problem and responsibility of the water organizations is to provide adequate, accessible and healthy drinking water for each individual. Disinfection process is required to ensure that the water taken from the source is clean and reliable for drinking. Applying liquid (sodium hypochlorite) and gas chlorine as a disinfectant in the drinking water is common in use. Although chlorine is highly effective in preventing waterborne diseases, it can also react with natural organic matters in water, leading to the formation of chemical compounds, disinfection byproducts (DBP), which are harmful to human health. Low and inadequate concentrations of chlorine in drinking water networks can pose risks to health by failing to disinfect contaminants that may enter the system. For this reason, the amount of chlorine to be given to the system at the beginning is a matter of great importance. However, high concentrations of chlorine is undesireable as like as complete depletion of the chlorine in the network, especially in terms of DBP formation. Hence, in drinking water networks where disinfection is provided by chlorine, more efficient researchs are needed to keep residual chlorine concentrations at certain levels and to manage chlorine concentrations. At this point, modeling studies about chlorine management in drinking water networks and the use of booster chlorine stations are gaining importance. The aim of this PhD study is to determine the number of chlorine booster stations in drinking water networks considering quality constraints and to evaluate them in terms of cost. For this purpose, an approach has been established to determine the locations of chlorine booster stations and the chlorine concentrations to be applied in these locations. The approach has been transformed into a software through codes that were integrated with the open-source EPANET model program developed by US-EPA. The developed software aims to improve chlorine concentration in the entire drinking water network, depending on quality and approach constraints. The software produces a solution by an approach that scans all options within the limits specified by the user. This approach is called "exhaustive search". Using the approach, the number and location of chlorine booster stations and the concentration of chlorine in the entire network at all times were determined. Thus, in addition to eliminating the risk of chlorine depletion in the network, the approach also contributes by reducing high concentration of chlorine applied at the source. The software developed within the thesis study has been tested on real and synthetic networks. For this purpose, taking into consideration the general hydraulic situation of Antalya drinking water network and the data of SCADA (Supervisory Control and Data Acquisition) and Geographical Information Systems (GIS), The Yeşilbayır network which constitutes about 10% of the drinking water network of Antalya province was selected as a study area. Within the scope of the thesis, first and foremost, with the cooperation of the General Directorate of ASAT, the entry and exit flows of the Yeşilbayır network was taken under control. The existing GIS data of the network system has been updated and the hydrological and water quality models of the region have been created by the use of the SCADA data in the region. EPANET model program have been used to model the networks. Model calibration and verification studies were carried out using chlorine and pressure measurements performed on the field, laboratory studies and SCADA data. In addition, laboratory studies have been carried out for understanding the water quality of the region and determining the chlorine bulk reaction coefficient. Within the scope of the PhD thesis, studies were made for determining the approximate costs of the chlorine booster stations to be installed in the drinking water networks. At this stage, the presence and absence of the SCADA system in drinking water networks were handled separately.