Optimization of conditions the precipitate elimination from the water supply pipelines (case study: Esfezar village in Southern Khorasan province)

This Study explores the influence of CaCO3 sedimentation in the Qanat system of Esfezar area in Southern Khorasan Province. Experiments were conducted to evaluate the decrease in transient water hardness in the drinking water supply network in the areas neighboring the Esferaz Qanat. The significance of the study lies in the fact that the Qanat under study is the only source of drinking water in the region. For the purposes of this study, experiments were carried out using a reservoir in which water pH was increased by adding lime to form sediments. Chemical coagulants were also added to accelerate the sedimentation process. From among the coagulants of FeSO4, Fe2(SO4)3, and CuSO4 used, optimizations revlead that Fe2 (SO4)3 yielded the best results at pH=9/5 in drinking water given the quality parameters of EC:440dS and pH = 7.7. Dimension analysis using the Reynolds Number was also conducted to simulate the qanat discharge, which was further calibrated against experimental results. The results obtained from the model showed that using a spiral pipe and Fe2(SO4)3 as the coagulant led to reduced transient hardness of water. The results also revealed that CaCO3 sedimentation reduced in the local water supply network.