Iron corrosion in drinking water distribution systems—Surface complexation aspects

Calculations on the surface complexation at an iron oxide surface in water containing carbonate and calcium ions were performed as a function of pH. The results are compared with experimental results from electrochemical measurements, coupon tests and with data collected from the pipe networks in different municipalities. A model is presented where the corrosion rate is shown to depend on the nature and concentration of surface complexes. The model applies both to the initial corrosion as determined by electrochemical experiments in the laboratory and to the steady state situation in the distribution networks.