Applied research on aquatic macrophyte fermentation broth in SBR denitrification

Area of Science:

• Environmental Microbiology
• Water Treatment Technologies
• Biogeochemistry

Background:

• Insufficient carbon sources limit biological nitrogen removal in traditional wastewater treatment.
• Reed fermentation broth offers a potential solution as a readily available carbon source.
• Understanding its impact on microbial communities and denitrification efficiency is crucial.

Purpose of the Study:

• To evaluate reed fermentation broth as an external carbon source for denitrification in sequencing batch reactors (SBRs).
• To investigate the influence of varying carbon-to-nitrogen (C/N) ratios on denitrification performance.
• To analyze the microbial community structure and its response to the addition of reed fermentation broth.

Main Methods:

• Leaching experiments using reeds with fluorescence excitation-emission spectrophotometry to characterize dissolved organic matter (DOM).
• Implementation of SBRs with controlled C/N ratios using reed fermentation broth as the carbon source.
• Microbial diversity analysis to assess the relative abundance of denitrifying bacteria.

Main Results:

• Reed material demonstrated a high capacity for carbon release (average 11.3 mg/g), primarily humic acid-like compounds.
• Addition of reed fermentation broth significantly promoted microbial denitrification.
• Optimal nitrogen removal efficiency of 88.3-96.4% was achieved at a C/N ratio of 6.
• The relative abundance of denitrifying bacteria in the SBR reached 38.5%.

Conclusions:

• Reed fermentation broth is a viable and effective external carbon source for enhancing denitrification.
• The optimal C/N ratio of 6 maximizes nitrogen removal efficiency in SBRs.
• Reed fermentation broth promotes the growth of anaerobic denitrifying bacteria, improving overall treatment performance.