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Updated: Jun 27, 2026
08:13
A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities
Published on: December 25, 2015
Autotrophic nitrogen removal in sequencing batch biofilm reactors at different oxygen supply modes
C Wantawin1, J Juateea, P L Noophan
1Department of Environmental Engineering, Faculty of Engineering, King Mongkut's University of Technology, Thonburi, Bangkok 10140, Thailand. chalermraj.wan@kmutt.ac.th
Summary
This study shows oxygen-limited autotrophic nitrification-denitrification can treat ammonia wastewater without added carbon. Continuous aeration in sequencing batch biofilm reactors achieved high nitrogen removal, demonstrating a cost-effective alternative.
Area of Science:
- Environmental Biotechnology
- Wastewater Treatment
- Microbial Ecology
Background:
- Conventional nitrification-denitrification is energy and carbon-intensive for low COD/N wastewaters.
- Autotrophic nitrogen removal offers a potential cost-effective alternative by utilizing bacteria.
- Oxygen-limited autotrophic nitrification-denitrification (OLAND) converts ammonia to dinitrogen gas.
Purpose of the Study:
- To investigate the efficacy of OLAND for treating synthetic ammonia wastewater devoid of organic carbon in a single step.
- To evaluate the performance of sequencing batch biofilm reactors (SBBRs) with different aeration modes (continuous vs. intermittent) for OLAND.
- To characterize the microbial community within the biofilm.
Main Methods:
- Lab-scale SBBRs with ring-laced fibrous carriers were inoculated with nitrifying sludge.
- Two aeration strategies were applied: continuous aeration (dissolved oxygen at 1.5 mg/L) and intermittent aeration.
- Wastewater ammonia loading rates and hydraulic retention times (HRTs) were varied.
- Microbial community analysis was performed using fluorescence in situ hybridization (FISH).
Main Results:
- Both SBBRs achieved high nitrogen removals (>50%).
- Continuous aeration at 1.5 mg DO/L showed slightly higher nitrogen removal (64%) than intermittent aeration (55%) at 0.882 g N/m2-day and 24 hr HRT.
- Ammonia was completely consumed at reduced loading (0.441 g N/m2-day) and extended HRT (48 hr), with removal efficiencies reaching 80% (continuous) and 86% (intermittent).
- Aerobic ammonia-oxidizing bacteria (AAOB) and anammox bacteria coexisted in the biofilm.
Conclusions:
- OLAND is a viable single-step process for treating carbon-deficient ammonia wastewater using conventional nitrifying sludge.
- Continuous aeration appears more effective in promoting nitrogen loss through competitive nitrite utilization by anammox bacteria.
- The co-occurrence of AAOB and anammox bacteria in the biofilm supports the OLAND mechanism.
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