Protective behavior of bacterial biofilm at high temperatures: Corrosion control strategies for thermal system pipes

Corrosion in water-heat interaction systems shortens the facility lifespan of transportation pipelines, leading to extensive perforation accidents and economic losses. This study investigates the impact of Geobacillus stearothermophilus on carbon steel corrosion, validated through the separate and combined application of biocide and biofilm dispersant. In high-temperature aqueous environments, the inoculation of this bacterium mitigates corrosion, as evidenced by a 33 % reduction in weight loss, a decrease in pitting depth from 16.2 to 0.8 μm, and an increase in Fe(II): Fe(III) of corrosion products. The addition of biocide (from 0 to 0.5 ppm) weakens the protective effect, while the combined use of both biocide and dispersant nearly abolishes the inhibition of corrosion. The local "anaerobic microenvironment" created by bacterial internal oxygen consumption and biofilm isolation of external oxygen alters corrosion products and directly inhibits aerobic corrosion. These findings provide a theoretical basis for the in-situ anti-corrosion of high-temperature pipelines by thermophiles.