Nitrogen removal and microbial communities in a three-stage system simulating a riparian environment

Area of Science:

• Environmental Microbiology
• Water Quality Engineering
• Biogeochemical Cycles

Background:

• Riparian zones are critical for nitrogen removal, but microbial contributions are often underestimated.
• Understanding microbial nitrogen transformations is key to optimizing wastewater treatment.
• Engineered systems can mimic natural riparian processes for enhanced pollutant removal.

Purpose of the Study:

• To investigate nitrogen removal efficiency and microbial community dynamics in a simulated engineered riparian system.
• To identify key microbial players involved in nitrogen transformations within the system.
• To assess the impact of ammonium loading and redox potential on nitrogen removal.

Main Methods:

• Construction of a three-stage engineered riparian system simulating natural environments.
• Monitoring of nitrogen removal rates (ammonium and nitrate) under varying conditions.
• Molecular biological analysis (bacterial diversity and population quantification) using 16S rRNA sequencing.

Main Results:

• Stage 1 achieved 41-51% of total nitrogen removal, significantly influenced by initial ammonium loading and redox potential.
• Anoxic/oxic (A/O) zones efficiently removed ammonium (6.8 g/m(2)/day), while anaerobic columns excelled in nitrate removal (11.1 g/m(2)/day).
• High bacterial diversity was observed in A/O zones, with specific nitrifying and denitrifying bacteria dominating the microbial community.

Conclusions:

• The engineered riparian system demonstrates significant potential for effective biological nitrogen removal.
• Key microbial groups, including ammonium-oxidizing and denitrifying bacteria, are crucial for system performance.
• This study enhances understanding of microbial functions in engineered riparian zones for improved nitrogen management.