Wasserseitige Möglichkeiten zur Reduzierung der Kupferabgabe aus Hausinstallationen in das Trinkwasser

In the scope of examinations for water-supply companies the effects of water treatment processes on the corrosion behaviour of materials which are used for water distribution (unalloyed steel, asbestos-cement, galvanized steel and copper) were tested by the Rhenian-Westphalian Institute of Waterchemistry and Watertechnology (IWW), Institute at the Gerhard-Mercator-University-GH Duisburg. Experimental studies have been made with copper sections and weighed ring specimens. The testing conditions were similar to those in a real domestic installation. Specimens taken at different testing times have been investigated with respect to mass loss measurements. The testing results demonstrate the possibility to estimate the concentrations on copper transported into the sewage sludge by domestic sewage. The testing conditions are described and the dominant influence of the water characteristics with respect to the water treatment processes are discussed. The experiments have shown that the central dosage of inhibitors, especially phosphate-products, is able to reduce the load of copper in domestic sewage in water systems with high concentrations of natural salts. The deacidification associated with water softening and slow-decarbonisation is qualified to reduce the load of copper in water systems with high concentrations on carbon dioxide.