Evaluation of corrosion and scaling potential in rural water distribution network of Urmia, Iran

Abstract

Water quality entering the drinking water distribution network often provides requirements for corrosion and scaling in rural areas due to the lack of suitable treatment methods. It leads to pipe clogging, reducing longevity of the equipment, and health problems caused by dissolved compounds in the water. The present study aims to evaluate the corrosion and scaling potential in water distribution networks of four villages located in different geographical locations of Urmia, Iran. In this descriptive cross-sectional study, 36 samples of water entering the villages of Dizaj-e Siavosh, Dolama, Gogtapeh, and Band distribution networks were analyzed according to standard methods for water and wastewater examinations. The corrosion and scaling potential were evaluated based on Ryznar stability (RSI), Langelier saturation (LSI), Puckorius scaling (PSI), and Larson–Skold (LRI) indices after determination of pH, total dissolved solids, sulfate, alkalinity, calcium hardness, and chloride. The results indicated that the values of LSI, RSI, PSI, and LRI indices were −1.94, 12.05, 12.20, and 0.68 for Gogtapeh water supply; −2.22, 12.72, 13.6, and 0.4 for Dizaj-e Siavosh water supply; −2.03, 12.1, 12.06, and 0.3 for Band water supply; and finally −2.09, 12.30, 12.59, and 0.29 for Dolama water supply, respectivly. Therefore, the water entering Gogtapeh distribution system has a tendency to scaling based on the LRI as an only appropriate index for the corrosion and scaling potential in this village. However, the water entering Dizaj-e Siavosh, Dolama, and Band distribution networks are highly corrosive based on the LSI, RSI, and PSI indices. The concordance between the analysis of chemical water quality and national standards could not be sufficient to confirm the water quality balance in terms of corrosion and scaling potential.