Experimental Investigation on the Effect of Physio-chemical Properties of Water on Galvanic Corrosion and Turbidity due to Iron Oxidation

Corrosion of water lines is a significant concern in materials science and engineering. Corrosion of water lines can have substantial economic and environmental consequences, as well as it can compromise the safety and dependability of water distribution systems. Red water, i.e., high water turbidity caused by the oxidation of suspended iron particles, is one of the most frequently reported consumer complaints in the water industry. However, knowledge of the effect or influence of water quality on corrosion and water turbidity is limited. The purpose of this work was to determine the effect of the most common water properties, such as dissolved inorganic carbon (DIC), pH, Cl-2, PO4-3 dissolved organic matter (DOM), and temperature, on iron corrosion and water turbidity due to iron oxidation in potable water systems. The main and interaction effects of these independent variables on turbidity were determined using a set of 2(6) full factorial design experiments. All independent variables except pH showed a significant influence on iron corrosion. It was determined that a higher temperature and the presence of chlorine resulted in a higher iron concentration due to corrosion. In this investigation, it was discovered that phosphate (PO4) reduces corrosion. Higher concentrations of DIC and DOM were also associated with an increase in iron corrosion. All independent variables except temperature showed a significant effect on turbidity. The phosphate concentration had the greatest beneficial effects on the turbidity reduction. The presence of disinfectants such as chlorine and DOM also reduced water turbidity. Additionally, the factorial experiments revealed a significant synergistic or antagonistic interaction between all these variables. DIC 50 mg/L, pH 6.5, chlorine 2 mg/L, phosphate 0.50 mg/L, and DOM 1 mg/L at 45 degrees C had the highest iron corrosion. Water with 5 mg/L DIC, pH 8.5, and 0.50 mg/L phosphate had the lowest corrosion rate at 21 degrees C. The maximum turbidity value of 20.45 NTU was observed for water having 50 mg/L of DIC and a pH of 8.5 at 25 degrees C. At 45 degrees C, water with a DIC of 5 mg/L, pH of 8.5, 2 mg/L chlorine, and 0.5 mg/L phosphate had the lowest water turbidity of 0.66 NTU. The findings of this study may be applicable to the water treatment plants in improving the finished water quality by reducing corrosion and red water occurrences, which will lead to fewer customer complaints. Further detailed studies are needed to get a better understanding of the mechanism of the influence of water quality on turbidity due to iron oxidation.