Water company
In distribution systems for industrial water, old steel pipelines are often still in use, which in most cases are not or poorly protected against corrosion. Microbial corrosion or MIC is a specific form of highly localized corrosion that is highly unpredictable in both location and time. It can occur on the inside of pipes in a water distribution system, but then it is often only detected after a leak has occurred. In order to determine the exact cause of such spills, targeted research must be carried out in a case-by-case manner.
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.
By proper analysis, the cause of such corrosion-related problems can be identified and a sustainable solution / improvement can be worked on.
