Microbial Diversity Dynamics in a Methanogenic-Sulfidogenic UASB Reactor

Area of Science:

• Environmental microbiology
• Biotechnology
• Wastewater treatment

Background:

• Sulfate reduction is key for SOx emissions control.
• Upflow Anaerobic Sludge Blanket (UASB) reactors are effective for wastewater treatment.
• Crude glycerol offers a sustainable carbon source for biological processes.

Purpose of the Study:

• To evaluate the long-term performance and microbial dynamics of a UASB reactor for SOx emissions treatment.
• To investigate the microbial community shifts during sustained operation.
• To understand the factors affecting sulfidogenic capacity.

Main Methods:

• Operation of a UASB reactor with crude glycerol for over 500 days.
• Monitoring of chemical species and sulfate reduction rates.
• Illumina 16S rRNA gene sequencing for bacterial community analysis.
• Sludge bed stratification sampling.

Main Results:

• The UASB reactor shifted from methanogenic to fully sulfidogenic activity.
• Methanogenic Archaea were outcompeted by sulfate-reducing bacteria, primarily Desulfovibrio.
• Long-term operation resulted in decreased sulfidogenic capacity due to slime accumulation.

Conclusions:

• UASB reactors can be adapted for long-term sulfate reduction using crude glycerol.
• Microbial community shifts, particularly the dominance of sulfate-reducing bacteria, drive reactor performance.
• Slime accumulation poses a challenge for sustained high performance in sulfidogenic UASB reactors.