METHODS TO PREVENT THE IRON CLOGGING IN RISING PIPES, FILTERING WELLS, WELL ELEMENTS AND OTHER WATER-CARRYING OBJECTS .2. LABORATORY AND FIELD EXPERIMENTS BY MEANS OF CATHODIC AND ANODIC POLARIZATION

The experimental facilities and conditions for the determination of the surface potential in the laboratory as well as of the ferric incrustation during field experiments for 3 ... 6 months are described. Compared with non-polarized pipe segments, the separation of ferric hydroxide is prevented or considerably reduced by a cathodic as well as anodic polarization. Unalloyed steel pipes at anodic current densities in the mA/m2 range show pipe-wall breakdowns caused by polarization. This effect does not occur at anodic polarization with current densities in the mu-A/m2-range within the experimental times.