COPPER CORROSION IN DRINKING-WATER DISTRIBUTION-SYSTEMS - THE INFLUENCE OF WATER-QUALITY

The copper corrosion in drinking water was studied using potentiodynam ic sweeps, coupon tests and field measurements in different Swedish mu nicipalities. The results were compared with equilibrium calculations. It was shown that for the first hours of water stagnation the system is not at equilibrium and the copper content is determined by the corr osion process. In the absence of calcium the corrosion rate increases linearly with the logarithm of the free carbon dioxide content (the su m of protonated carbonic acid and dissolved carbon dioxide). In the pr esence of calcium both the corrosion rate and the copper concentration in the water increases with the ratio between the free carbon dioxide and the calcium content. Presence of chloride ions in normal drinking water concentrations decreases the corrosion rate. (C) 1997 Elsevier Science Ltd.