Investigation of Mild Steel Corrosion by Clay Soil Environment

Abstract

This research work was carried out to observe the microbiologically induced corrosion in relation to mild steel of clay soil environments. We analyzed the physicochemical parameters and ascertained their biological features and impacts in the soil environment. In course of this research work, clay soil samples were collected in exactly four different locations at 100 m to 200 m and mixed together to form a single sample (sample D). The different clay soil samples were collected from a shell pipeline area at Uzere Community, Isoko South Local Government Area, Oleh Delta State, Nigeria and same was done at Otosega Shell Gas Pipeline Community, Ogbia Local Government Area, Bayelsa State, Nigeria. The results of the physicochemical and biological characteristics showed that the levels of measured parameters in soil samples are consistent with the conditions in an environment that promotes and sustains microbiologically influenced corrosion. The research further shows that the method of weight loss as seen in the results indicates that the mild steel was degraded as a result of total corrosion experienced. The obtained results reveal that the temperature of the soil samples of site B to site D from Bayelsa State and Delta State locations are within the range of 27.2°C and 27.2°C, respectively. This shows that the temperature in this region is suitable for
bacteria growth, where the optimal growth temperature for bacteria lies between 25°C and 35°C. Therefore, the soil samples of Sites B and D exhibit the necessary qualities for promotion and sustenance of microbiologically influenced corrosion based on the soil corrosivity rating or index of 8 and 8, respectively. Finally, the microstructure examination showed that the presence of biofilm on
the surface of the mild steel caused pitting corrosion.