Rapid start-up and nitrogen loading response of single-stage partial nitritation-anammox system using multi-channel...

Area of Science:

• Environmental Engineering
• Microbiology
• Biotechnology

Background:

• Partial nitritation-anammox (PN/A) processes face challenges like slow start-up and instability under fluctuating loads.
• Efficient nitrogen removal from wastewater is crucial for environmental protection.

Purpose of the Study:

• To investigate the performance and microbial community evolution of a novel airlift multi-channel internal circulation bioreactor (AMICR) for PN/A.
• To assess the AMICR's adaptability to increasing nitrogen loading rates after rapid start-up.

Main Methods:

• Continuous operation of the AMICR for 253 days.
• Stepwise increase of ammonia loading rate from 200 to 1100 mg/L.
• High-throughput sequencing for microbial community analysis.

Main Results:

• Rapid start-up within 80 days and stable PN/A pathway establishment.
• Achieved 86.52% total nitrogen removal efficiency and a nitrogen removal rate of 2.835 kg N/(m³·d).
• Observed enrichment of anaerobic ammonium-oxidizing bacteria (AnAOB) and synergistic microbial communities.

Conclusions:

• The AMICR facilitates rapid start-up, stable PN/A, and robust nitrogen removal under increasing loads.
• The bioreactor's design supports DO stratification, sludge recirculation, and microbial niche differentiation.
• This technology shows promise for practical high-strength wastewater treatment.