Effect of crevice morphology on SRB activity and steel corrosion under marine foulers

Localized corrosion of submerged steel H-piles was detected in a Florida bridge spanning over a brackish river. Analysis of the water showed proliferation of sulfate reducing bacteria (SRB). The steel piles had coincident heavy marine growth that may support biofilms and biocorrosion. The objective of the research described here was to identify the role of the physical morphologies of macrofouling on SRB activity and the aggravation of microbiologically influences corrosion (MIC) of submerged steel bridge. Laboratory experiments were carried out in nutrient-rich environments inoculated with SRB, with both porous and laminate crevice conditions characteristic of soft and hard marine fouling. It was confirmed that SRB proliferation can occur within the crevice environments, but aeration levels under crevices with interaction with the bulk solution can affect SRB activity. Electrochemical impedance spectroscopy provided separation of environmental parameters and surface reaction parameters for the complicated systems relating to corrosion under the porous and laminate crevice geometries.