Material-driven microbiologically influenced corrosion mechanisms in drinking water distribution systems

Area of Science:

• Environmental Science
• Microbiology
• Materials Science

Background:

• Microbially influenced corrosion (MIC) accelerates degradation of drinking water distribution systems (DWDS) and compromises water quality.
• Limited understanding exists on how pipe material and linings influence biofilm formation and drive MIC.
• Investigating these interactions is crucial for maintaining infrastructure integrity and water safety.

Purpose of the Study:

• To investigate the interplay between pipe material, protective linings, biofilm, and MIC in field-aged DWDS pipes.
• To characterize material-specific microbial communities and their role in corrosion processes.
• To establish a non-invasive monitoring strategy for corrosion risk assessment.

Main Methods:

• Analyzed 21 field-aged pipes (cast iron, ductile iron, steel) using morphological characterization, microbial community profiling, and biochemical analysis.
• Quantified biofilm densities and identified microbial taxa, including iron-oxidizing and sulfate-reducing bacteria.
• Assessed functional genes related to sulfate transformation and correlated microbial activity with iron dissolution.

Main Results:

• Unlined steel pipes exhibited significantly higher corrosion and biofilm densities (13.5-fold) compared to cement-lined pipes.
• Material-specific microbial communities were identified: Sideroxydans and Desulfovibrio in unlined pipes, Shewanella and Streptococcus in lined pipes.
• Sulfate-rich environments promoted sulfate-reducing bacteria (SRB) in steel pipes, while lactic acid production by Streptococcus drove iron dissolution in lined pipes.

Conclusions:

• Pipe material and lining type dictate distinct MIC mechanisms and microbial guilds.
• Identified key microbial players (e.g., Desulfovibrio, Sideroxydans, Streptococcus) and functional genes (cysI/cysJ) driving corrosion.
• Developed a non-invasive monitoring strategy linking effluent biomarkers to pipe wall biofilm dynamics for corrosion risk assessment.