Microbial-induced concrete corrosion under high-salt conditions: Microbial community composition and environmental multivariate association analysis

The corrosion of concrete materials in urban sewage pipes by microorganisms is a serious issue in wastewater networks around the world. There has been no systematic study conducted on material corrosion by microorganisms, particularly for high-salt environments in coastal cities. This study compared and analysed reactors under different salinities, and the 16S ribosomal ribonucleic acid gene sequence method was used to analyze the bacterial communities associated with concrete corrosion. Redundancy analysis demonstrated that chemical oxygen demand, volatile fatty acids, and sulphate altered the structure and distribution of the microbial community. The predominant bacteria, Proteobacteria, accounted for 41.85% of the seawater group. Among them, the sulphur functional microorganism, Desulfomicrobium, accounted for 4.14%. These bacteria can decompose macromolecular organic matter to provide energy for reproduction. Furthermore, they continue to provide sulphur for the eosinophilic sulphur-oxidising bacteria attached to the surface of the high alkaline concrete sample. The aggregated sulphur-oxidising bacteria produce biological sulphuric acid, leading to corrosion and damage to the concrete structure. Salinity promoted the aggregation of corrosion-inducing bacteria, accelerating the growth of corroding microorganisms on the concrete material of coastal urban sewage pipes.

Automated summary

The study found that factors such as sulphate, volatile fatty acids, and chemical oxygen demand affect the structure and distribution of microbial communities in high-salt environments, leading to concrete corrosion. The sulphur functional microorganism Desulfomicrobium and eosinophilic sulphur-oxidising bacteria play important roles in concrete corrosion, causing damage to the concrete structure through their combined actions.