Evaluating Corrosion and Scaling Potential of Drinking Water Supplies in Juybar, North of Iran

Abstract

Background and purpose: One of the major factors in the quality of drinking water is corrosion and scaling. The aim of the present study was to evaluate corrosion and scaling potential of drinking water supply network in Juybar (A city in Iran). Materials and Methods: 60 samples of drinking water in distribution network were collected randomly in summer and autumn seasons and transferred into laboratory. Some parameters including temperature, TDS, pH, total alkalinity and hardness and calcium hardness were measured based on the standard methods. The corrosion and scaling potential of water have been evaluated by Langelier, Ryznar, Puckorius and aggressive indices. The collected data were analyzed using descriptive statistics. Results:The mean values of pH, TDS, total alkalinity and calcium hardness in summer were 7.6, 637.5, 300, and 120 mg/l, respectively; and in autumn were 7.5, 646.5, 301, and 118 mg/l, respectively. The Langelier index in summer and autumn were 0.57 and 0.5, respectively, which showed that water had a potential for scaling. The Ryznar index in summer and autumn were 6.42 and 6.53, respectively indicating that water samples had neither scaling, nor corrosive potential. The Puckorius index in water samples was also determined to be 5.83 and 5.92 in summer and autumn, respectively, which showed that the samples were depositing water. Based on the aggressive index, the water samples in summer and autumn were 12.65 and 12.59, respectively, showing that water was mild scaling. Conclusion: This study showed that the drinking water of Juybar city has tendency to scaling.

Hydraulic and Technological Investigations of a Phenomenon Responsible for Increase of Major Head Losses in Exploited Cast-Iron Water Supply Pipes

“…If LSI = 0, then the water does not tend to precipitate sediments and its corrosive features are also weakened. If LSI < 0, then the water does not tend to precipitate sediments and its corrosive features are strengthened [68]. In relation to the LSI, the Ryznar stability index broadens the range of parameters liable to affect corrosion and water hardness because it considers magnesium content, temperature and dry residue, which indirectly considers typical components of dissolved substances, i.e., chlorides and sulfides.…”

“…In relation to the LSI, the Ryznar stability index broadens the range of parameters liable to affect corrosion and water hardness because it considers magnesium content, temperature and dry residue, which indirectly considers typical components of dissolved substances, i.e., chlorides and sulfides. The RSI has a more extended corrosivity range than the LSI: 4 < RSI < 5-strong precipitation of sediment, 5 < RSI < 6-medium precipitation of sediment, 6 < RSI < 7-weak precipitation of sediment or initial corrosion, 7 < RSI < 7.5corrosion, 7.5 < RSI < 9-strong corrosion, RSI > 9-very strong corrosion [56,57,[68][69][70][71]. Basing on the performed determinations of quality parameters of the water transported by the investigated cast-iron pipelines (Table 1), the Langelier saturation index was calculated, which amounted to 0.07, which indicates very low precipitatibility, whereas the Ryznar index amounted to 7.17, which indicates very low corrosive features of the water flowing through the investigated pipelines.…”

“…The pipes under investigation had been applied for the transport of underground water taken from quaternary formations with use of bored wells from the depth of 28 m. The physical and chemical characteristic of the water transported by the investigated cast-iron pipes is presented in Table 1. A number of methods exist for determination of aggressive and corrosive features of water [50][51][52][53]. In aim to determine the corrosive features of water flowing in the investigated pipes, the Langelier Saturation Index (LSI) and the Ryznar Stability Index (RSI) [54][55][56][57] were calculated.…”