The present paper deals with water quality modification in metal distribution pipes, caused by the development of electrochemical corrosion processes. More particularly it is aimed at investigating metal release during stagnation of water in copper pipes. At this aim several experiments are developed, varying water quality characteristics and stagnation length, to ascertain the dependence of copper release on both water composition and contact lime between water and copper. Copper is chosen as plumbing material because of its wide use in drinking water distribution systems all around the world, and because of its recognized toxicity at high dosages. The effect of different concentrations of bicarbonates and sulphates on metal release is studied, assuming stagnation periods ranging between 15 and 90 minutes. A special corrosion cell is used as experimental apparatus, and the so called corrosion potential stagnation flow (CPSF) theory is followed for copper concentration monitoring, which means that copper concentration is monitored not only by direct measuring it, but also by measuring the corrosion potential of the metal surface during stagnation episodes. Experimental data allow to verify the formation of a protective layer on copper surface which lowers the corrosion rate, reducing the metal release. This layer is more likely to be formed at higher bicarbonate and sulphate concentrations. The effect of longer stagnation times results to be not dissimilar from that observed varying water quality characteristics. The corrosion potential always exhibits a typical and reproducible trend: it decreases at the beginning of each stagnation period, and then slightly increases once more. The minimum reached by the corrosion potential is function of the water quality, being less pronounced for higher alkalinity values and higher sulphate concentrations, and more pronounced in the apposite case. This trend is well explained by the development of the corrosion process and by the formation of the over mentioned protective layer. The experimental data allow to validate the CPSF theory, showing the existence of a direct correlation between the potential at the end of each stagnation period, and the corresponding total copper concentration in the stagnated water.

Drinking Water Contamination Due to Internal Corrosion of Copper Distribution Pipes / Fabbricino, Massimiliano; Panico, Antonio; Scotto, A.; Tegazzini, V.. - ELETTRONICO. - (2005), pp. 384-389. (Intervento presentato al convegno 9th International Conference on Environmental Science and Technology tenutosi a Rhodes Island (GREECE) nel 1-3 September).

Drinking Water Contamination Due to Internal Corrosion of Copper Distribution Pipes

FABBRICINO, MASSIMILIANO;PANICO, ANTONIO;
2005

Abstract

The present paper deals with water quality modification in metal distribution pipes, caused by the development of electrochemical corrosion processes. More particularly it is aimed at investigating metal release during stagnation of water in copper pipes. At this aim several experiments are developed, varying water quality characteristics and stagnation length, to ascertain the dependence of copper release on both water composition and contact lime between water and copper. Copper is chosen as plumbing material because of its wide use in drinking water distribution systems all around the world, and because of its recognized toxicity at high dosages. The effect of different concentrations of bicarbonates and sulphates on metal release is studied, assuming stagnation periods ranging between 15 and 90 minutes. A special corrosion cell is used as experimental apparatus, and the so called corrosion potential stagnation flow (CPSF) theory is followed for copper concentration monitoring, which means that copper concentration is monitored not only by direct measuring it, but also by measuring the corrosion potential of the metal surface during stagnation episodes. Experimental data allow to verify the formation of a protective layer on copper surface which lowers the corrosion rate, reducing the metal release. This layer is more likely to be formed at higher bicarbonate and sulphate concentrations. The effect of longer stagnation times results to be not dissimilar from that observed varying water quality characteristics. The corrosion potential always exhibits a typical and reproducible trend: it decreases at the beginning of each stagnation period, and then slightly increases once more. The minimum reached by the corrosion potential is function of the water quality, being less pronounced for higher alkalinity values and higher sulphate concentrations, and more pronounced in the apposite case. This trend is well explained by the development of the corrosion process and by the formation of the over mentioned protective layer. The experimental data allow to validate the CPSF theory, showing the existence of a direct correlation between the potential at the end of each stagnation period, and the corresponding total copper concentration in the stagnated water.
2005
Drinking Water Contamination Due to Internal Corrosion of Copper Distribution Pipes / Fabbricino, Massimiliano; Panico, Antonio; Scotto, A.; Tegazzini, V.. - ELETTRONICO. - (2005), pp. 384-389. (Intervento presentato al convegno 9th International Conference on Environmental Science and Technology tenutosi a Rhodes Island (GREECE) nel 1-3 September).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/118344
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