Intensified simultaneous nitrification and denitrification performance in integrated packed bed bioreactors using...

Area of Science:

• Environmental Science
• Environmental Engineering
• Microbiology

Background:

• Wastewater treatment requires efficient methods for removing nitrogen compounds.
• Simultaneous nitrification and denitrification (SND) is crucial for nitrogen removal, especially in low C/N ratio wastewaters.
• Poly(3-hydroxybutyrate-hydroxyvalerate) (PHBV) shows potential as a biomaterial in bioreactor applications.

Purpose of the Study:

• To investigate the effectiveness of integrated packed bed bioreactors using PHBV for simultaneous nitrification and denitrification (SND).
• To compare the performance of different PHBV dosing methods (grainy vs. strip) in wastewater treatment.
• To analyze the microbial community structure and its role in nitrogen removal.

Main Methods:

• Design and implementation of integrated packed bed bioreactors utilizing PHBV.
• Application of different PHBV dosing methods (grainy and strip).
• Monitoring of ammonium (NH₄⁺-N) and nitrate (NO₃^--N) removal efficiencies.
• Microbial community analysis using gene markers (amoA, nirS) and sequencing.

Main Results:

• The bioreactor achieved 88.62% NH₄⁺-N removal with aeration.
• Higher NO₃^--N removal efficiency was observed with grainy PHBV (95.21%) compared to strip PHBV (93.34%).
• Microbial analysis revealed a preference for microbes harboring amoA and nirS genes to attach to ceramsite, with significant differences in community composition.

Conclusions:

• Grainy PHBV is a feasible and effective material for packed bed bioreactors enabling simultaneous nitrification and denitrification.
• The developed bioreactor system efficiently removes both NH₄⁺-N and NO₃^--N from wastewater with low C/N ratios.
• Microbial communities play a key role in the SND process within these bioreactors.