Drinking Water Decline Due to Internal Corrosion of Copper Pipes

This paper deals with the effects, caused by electrochemical corrosion processes occurring in distribution pipes, on drinking water quality. These studies focus on copper tubes, as this metal is widely used as plumbing material and is considered toxic by the WHO (World Health Organization), that recommends a maximum drinking water concentration of 2 mg l-1. To investigate the dependence of copper release on both water composition and contact time between water and copper, several experiments were carried out and a mathematical model was also developed. On metal release, both effects of different concentrations of bicarbonates, sulphates, phosphates and chlorides and different stagnation times, between 15 and 90 minutes, were studied. As experimental apparatus, a special corrosion cell was used. To verify the existence of a direct correlation between the corrosion potential of the metal surface and the total dissolved copper concentration in the stagnating water, measurements of both parameters, respectively, were taken during and at the end of each stagnation episode. The experimental results allow the copper concentration in drinking water to be quantified by measuring the potential corrosion, instead of analyzing water, reducing in this way the monitoring costs and time.