Anoxic-Aerobic-Anoxic sequencing batch reactor for enhanced nitrogen removal

Area of Science:

• Environmental Science
• Environmental Engineering
• Microbiology

Background:

• Wastewater treatment requires efficient removal of organic carbon and nitrogen.
• Simultaneous removal is challenging and often energy-intensive.

Purpose of the Study:

• To establish and optimize an anoxic-aerobic-anoxic process for simultaneous organic carbon and nitrogen removal.
• To understand the biochemical reactions and microbial communities involved.

Main Methods:

• Utilized a sequencing batch reactor with an anoxic-aerobic-anoxic configuration.
• Optimized dissolved oxygen (DO) levels and anoxic periods.
• Conducted inhibition studies and microbial community analysis.

Main Results:

• Achieved TOC, NH4+-N, and TN removal efficiencies of 98.76%, 98.52%, and 88.23% respectively.
• Identified optimal DO of 1.5 mg/L and 1-hour pre- and post-anoxic periods.
• Confirmed heterotrophic nitrification/direct conversion and aerobic denitrification as key pathways.

Conclusions:

• The anoxic-aerobic-anoxic process effectively removes organic carbon and nitrogen simultaneously.
• Limited aeration and varied redox conditions are beneficial for nitrogen removal, reducing energy costs.
• Microbial community analysis supports the identified nitrogen removal mechanisms.