Microbial community characterization in advanced water reclamation for potable reuse

Area of Science:

• Environmental microbiology
• Water treatment technologies
• Microbial ecology

Background:

• Advanced water reclamation is crucial for potable reuse.
• Understanding microbial communities in treatment processes is vital for performance and safety.
• Coagulation/Flocculation/Clarification/Granular Media Filtration (CFCGMF) and Ozone-Biological Activated Carbon (O3/BAC) are key treatment steps.

Purpose of the Study:

• To characterize microbial community structure and composition in CFCGMF and O3/BAC treatment steps.
• To understand the ecological dynamics influencing unit process performance.
• To identify potential bacterial pathogens in treated water.

Main Methods:

• 16S metagenomic sequencing was used to analyze bacterial microbiomes.
• Microbial richness, variations, and similarities were assessed at each treatment step.
• Species were classified by lifestyle (free-living vs. attached-living).

Main Results:

• A total of 3801 species were detected across both treatment steps.
• Proteobacteria, Bacteroidetes, Actinobacteria, and Firmicutes were the most abundant phyla.
• Betaproteobacteria was the predominant class; CFCGMF showed lower pathogenic bacteria abundance (2%) than O3/BAC (8%).

Conclusions:

• Microbial community characterization is essential for understanding treatment mechanisms and ensuring public health.
• Organisms tolerating ozone and forming biofilms shape the microbial community in biofilters.
• Potential pathogenic bacteria were detected in low abundances in treated water, necessitating continued monitoring.