Biocide Cocktail Consisting of Glutaraldehyde, Ethylene Diamine Disuccinate (EDDS), and Methanol for the Mitigation of Souring and Biocorrosion

Souring and microbiologically influenced corrosion (MIC) caused by sulfate-reducing bacteria (SRB) are major problems in the oil and gas industry as well as other industries such as water utilities. SRB biofilms are notoriously difficult to treat. More effective dosing of biocides is desired to deal with increasing environmental restrictions and costs. This work presents an effective green biocide system consisting of glutaraldehyde (C₅H₈O₂), ethylene diamine disuccinate (EDDS [C₁₀H₁₆N₂O₈]), and methanol (CH₄O) against souring and MIC caused by SRB. Desulfovibrio vulgaris (ATCC 7757) was used in this work in the full strength ATCC 1249 medium and a modified ATCC 1249 medium with only four ingredients (MgSO₄, lactate [C₃H₅O₃⁻], yeast extract, and Fe²⁺) at concentrations 1/4 of those in the full medium. Tests were carried out in 125 mL anaerobic vials. It was found that the triple combination of 30 ppm (w/w) glutaraldehyde, 1,000 ppm EDDS, and 10% (v/v) methanol was considerably more effective than glutaraldehyde alone and the combination of glutaraldehyde and EDDS in the inhibition of souring, SRB biofilm establishment, and MIC pitting of C1018 carbon steel (UNS G10180) in the presence of 2% (w/w) sand particles in batch tests.