Process performance and microbial community structure in thermophilic trickling biofilter reactors for biogas...

Area of Science:

• Microbiology
• Environmental Engineering
• Biotechnology

Background:

• Biological methanation offers a sustainable route for converting waste gases into valuable methane.
• Thermophilic trickling biofilters are a promising technology for efficient gas upgrading.

Purpose of the Study:

• To evaluate the process performance of lab-scale thermophilic trickling biofilters for biological methanation.
• To determine the microbial community structure and spatial distribution within the biofilters.

Main Methods:

• Operation of two lab-scale thermophilic trickling biofilters for 94 days.
• Gas analysis to determine methane purity and productivity.
• DNA sequencing to characterize microbial consortia in biofilm and liquid media.

Main Results:

• Stable and robust operation achieved with single-pass gas flow.
• Output gas quality (>97% methane) comparable to commercial biogas upgrading systems.
• High methane productivity (>1.7 LCH4/(LR·d)) at a hydrogen loading rate of 7.2 LH2/(LR·d).
• Methanothermobacter sp. predominated in the biofilm; unknown Clostridia were abundant in both biofilm and liquid; acetate-utilizing bacteria were prevalent in liquid samples.

Conclusions:

• Thermophilic trickling biofilters are effective for producing high-purity methane from hydrogen and carbon dioxide.
• The study provides insights into the microbiome structure and its role in biological methanation.
• The findings support the use of these biofilters as a substitute for natural gas production.