Assessing the Corrosion and Scaling Potential of Drinking Water in Morocco Using Water Stability Indices

Abstract

Corrosion and scaling occur in water distribution systems. However, not much data is available concerning this issue in Morocco. This study aimed to evaluate the corrosive and scaling potential of drinking water in the water distribution systems of several cities in Morocco using water stability indices and other physicochemical parameters. For this purpose, 100 samples were collected, mainly from the cities in the Rabat-Salé-Kenitra region of Morocco. The results of the physicochemical analysis of 100 collected samples show that the means of the pH, total alkalinity, calcium hardness, chloride, temperature, and total dissolved solids are 7.577 ± 0.23, 173.6 ± 52.04 mg/l as CaCO 3 , 212.57 ± 98.18 mg/l as CaCO 3 , 418.7 ± 407.75 mg/l, 25.16 ± 1.58 °C, 597.5 ± 435.74 mg/l, respectively. The mean values of the water stability indices are 0.1158 ± 0.38, 7.345 ± 0.68, 7.132 ± 0.86, and 12.41 ± 0.35 for the Langelier saturation index (LSI), the Ryznar stability index (RSI), the Puckorius scaling index (PSI), and the aggressive index (AI), respectively. The water samples show corrosive tendencies of 41%, 75%, 97%, and 13% based on the LSI, RSI, PSI, and AI, respectively, and are considered supersaturated and likely to scale, corrosive, and non-aggressive. The water samples in Rabat, Salé, Bouknadel, and Kenitra were mostly supersaturated with a tendency to scale, with the highest percentage of stable water while the water in Khemisset and Tiflet was mostly corrosive, with Tiflet recording the highest chloride content of 3220.1 mg/l. The scaling and corrosive potential of water varied depending on the source of water in each city. Therefore, it is essential to continuously supervise the stability of water at different points of water distribution systems, create an adapted approach for each city, and instill strict national standards for the physicochemical parameters that affect corrosion and scaling to ensure safe drinking water.