Microbially-influenced corrosion, victaulic couplings, water treatment, and DNA studies

The utilities at a major government office facility include both condenser and chilled water systems. Though they are similar, the water in the condenser system is regularly aerated, while the chilled water is a closed system. Piping in both is largely carbon steel, with a minor amount of cast iron. Both systems use Victaulic mechanical couplings (Victaulic Company) rather than welded joints. The joints in the condenser section of the system are deeply corroded, while the chilled water system is in good condition. The cause appears to be initial system pressure testing without biocide, followed by several months of no use at all. Microbially-influenced corrosion (MIC) started below the gaskets in the joints and could not be stopped. Polymerase chain reaction analysis allowed identification of the bacteria involved after the system was dismantled. The entire condenser water system had to be replaced.