Investigation of sulfate-reducing bacteria growth behavior for the mitigation of microbiologically influenced corrosion (MIC)
SRB in the oil and gas industry have created serious problems. Since the 1980s considerable efforts have been devoted to understanding the corrosion process due to SRB, while the interactions between the biological systems and the environment still remain obscure. A thorough study of the parameters that affect SRB growth with respect to mitigating SRB related MIC is mandatory because the growth behavior of SRB is believed to be an important factor in the MIC process due to SRB. This study focused on the factors influencing the growth of SRB and the corrosion of steel. The ATCC 7757 strain of Desulfovibrio desulfuricans was used as a representative of SRB in this work. Corrosion due to SRB only occurs in the presence of sulfate ions; however, experimental results in this work showed that high concentrations of sulfate ions inhibited sulfate reduction by SRB. The ferrous ion concentration plays a significant role in the corrosion process and corrosion rate of steel. Experimental results indicated high concentrations of ferrous ion aggravated the corrosion of steel. The adhesion of SRB to metal surfaces affects the corrosion process substantially. Celite beads exhibited some inhibition of cell migration to the biofilm by reducing the planktonic SRB cell count considerably. However, it reduced the corrosion rate only to a small extent. A new efficient solid medium for SRB plating was developed as an important way to isolate and quantify the sessile bacteria in the biofilm. The solid media consisting of Wort Agar plus Yeast Extract take only two days for SRB colonies to form at room temperature without using a hydrogen atmosphere. This facilitates the analysis of SRB cells in biofilms. Furthermore, this work also included the evaluation of the synergistic effect of EDTA (a common chelator) and glutaraldehyde (a common biocide) in the treatment of SRB. It was found that EDTA considerably improved the inhibition of planktonic SRB growth by glutaraldehyde.
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:sulfate reducing bacteria growth behavior mitigation microbiologically influenced corrosion mic
Date of Publication:01/01/2004