Journal of Emerging Trends in Engineering and Applied Sciences: Research Areas

Article Title: Estimation of Microbiologically Influenced Corrosion of X60 Steel Exposed to a Natural Freshwater Environment
by A.Rim-Rukeh and G. Irerhievwie

Abstract:
The effects of microbial activities on the corrosion of X60 Steel exposed to a natural freshwater environment (Orashi River) have been experimental determined. In the petroleum industry in Nigeria, construction material for pipeline is made of X60 steel and such pipeline traverses a number of natural freshwater environments. Outcome of this investigation provides opportunities for examining the possible effect of microorganisms on the corrosion of X60 steel. Physicochemical and biological characteristics of water samples show the levels of measured parameters that favours the promotion and sustenance of microbiologically influenced corrosion. Total bacterial population varied from 105cfu/ml to 106cfu/ml in all water samples indicating a population that can initiate microbial corrosion. Corrosion rate was calculated to be 0.79 mpy after 6920 hours of test period. An approximate linear relationship between mass loss and time for the first 5376 hours was obtained. An approximate sinusoidal curve of log of mass loss with time suggested a second order chemical reaction between the microorganisms and the metal. The presence of biofilms on the surface of the X60 steel accounts for the observed reactions. Biofilm formation on the surface of the coupons followed the four phases of biofilm evolution biomass amount per carrier for the period of the test. In all these phase, biomass accumulation increased with time. The superficial biomass formed on the metal surfaces increased with time during the experimental period.

Keywords: microbiologically influenced corrosion, X60 steel, Orashi River, biofilms, corrosion rate.

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