Microbial corrosion in an industrial water distribution system

The damage investigation clearly showed that internal corrosion had occurred in the pipes in the form of corrosion pits that also pierced the pipe wall in a number of places. The perforations and pits were always located under so-called tubercles, these are layered accumulations of corrosion products, sometimes several centimeters high. Microscopic examination (SEM-EDX) showed that certain layers in the corrosion product contain sulfur. Close to the perforations in the tube, bacterial populations were found in which sulphate-reducing bacteria were emphatically present and active.

Since in this case it concerns damage occurring under a biofilm and thick layers of corrosion products, it is recommended to tackle the MIC problem with a biocide with a relatively long residence time in the pipe system. Such an agent can penetrate better into the biofilm and layer with corrosion products and thus exert its effect. In addition, a recommendation has been made to set up a reliable corrosion monitoring system with which the effect of the biocide dosages in the pipe system can also be monitored.