Development of an On-Line System to Monitor the Rate of Corrosion and Metal Release in Drinking Water

摘要

This paper describes results of experiments and theoretical modeling relevant tothe development of a new approach to on-line monitoring of metal release andcorrosion. This is done by means of measurements of changes of the corrosionpotential (Ecorr) during stagnation and flow (CPSF approach). In the absence offree chlorine, the values of Ecorr are strongly correlated with the concentration ofcopper. In the presence of chlorine, the behavior of Ecorr has an additional feature:immediately following the start of a stagnation episode, the corrosion potentialrapidly decreases and reaches a minimum. This type of Ecorr behavior wasexamined based on numerical modeling. It was determined that the intensity ofthe Ecorr transients is sensitive to the presence of chlorine and increases linearlywith its concentration. It was concluded that for systems for which the behavior ofEcorr without chlorine in CPSF cells has been explored, its quantification in thepresence of chlorine can be utilized to determine the rate of free chlorine decayand the corrosion current defined by the reduction of oxygen.