Prediction and Measurement of Scaling Values in Polyethylene Pipes Using Scaling and Corrosion Tests and Offering Effective Solutions

Corrosion in water distribution system introduces metals to convey system. Water with scaling potential can produce scale layers on internal section of pipelines and reduce internal diameter of the pipeline. Ongoing formation and removal of scaling cause difficulties such as accumulation of scale material in junctions، on the tap component، and so on. The aim of this research was determining the corrosion and scaling potential of drinking water in some rural areas of Markazi province and comparison of results with marble test. The characteristics of scale sediments will be different due to application of polyethylene pipes in this region. For this reason، temperature، pH، Total Dissolved Solids، Calcium، Calcium Hardness، Total Alkalinity، and Bicarbonate concentration were determined in the laboratory according to Standard Methods for the Examination of Water and Wastewaters manual. Finally، values of Langlier Saturation Index (LSI) and Ryznar Stability Index (RSI)، and marble test were determined. The results showed that the values for Langlier Saturation Index were positive (>0) and for Ryznar Stability Index were negative (<0). Therefore، average values for Langlier and Ryznar indices for Sarahrood village were equal to 0. 44 and 6. 97، respectively. The respective values for Joftan village with spring water supply were 0. 38 and 7. 25 and for well water sources were equal to 0. 98 and 6. 04. Primary alkalinity value was higher than the secondary alkalinity value in the marble test. According to the values of Langlier and Ryznar indices، water of this region tends to scale. Marble test also proved these results. Different methods have been recommended to remove formed sediments and among these، adjusting pH and periodic acid washing are the best introduced options for these regions.