Interrogating nitritation at a molecular level: Understanding the potential influence of Nitrobacter spp.
Lindsey Smoot1, Jason Mellin1, Cynthia K Brinkman1
1Department of Civil and Environmental Engineering, University of Idaho, Moscow, ID, USA.
Water Research
|September 16, 2022
Summary
Partial nitritation in biological nutrient removal (BNR) can reduce energy use in water resource recovery facilities (WRRFs). This study identifies key operational strategies and microbial insights for achieving efficient nitritation and improving effluent quality.
Area of Science:
- Environmental Science
- Microbiology
- Environmental Engineering
Background:
- Water resource recovery facilities (WRRFs) face pressure to enhance nutrient removal while reducing energy consumption.
- Biological nutrient removal (BNR) processes are energy-intensive, particularly those involving nitrogen and phosphorus removal.
- Partial oxidation of ammonia to nitrite (nitritation) offers a potential strategy to decrease energy demands and environmental impact.
Purpose of the Study:
- To investigate the microbial mechanisms and operational parameters that enable sustained nitritation in BNR systems.
- To understand how mixed microbial consortia in real wastewater adapt to and perform nitritation.
- To identify optimal conditions for inducing and maintaining partial nitritation for improved wastewater treatment.
Main Methods:
- Bench-scale BNR systems were employed to culture and study mixed microbial consortia.
- Process monitoring included measurements of nutrient concentrations and dissolved oxygen (DO).
- Advanced techniques such as phylogenetic, transcriptomic, and metabolomic analyses were used to interrogate microbial responses.
Main Results:
- BNR configurations achieved high nitrite accumulation ratios (64-82%) with excellent effluent quality.
- Key operational parameters identified include ammonia-based aeration control (2-3 mgN/L setpoint), aerobic DO levels (1.0-2.0 mg/L), and post-anoxic operation integrated with enhanced biological phosphorus removal (EBPR).
- Nitritation was sustained despite the presence of Nitrobacter spp., suggesting functional impairment of nitrite oxidoreductase.
Conclusions:
- Partial nitritation is achievable and beneficial for energy reduction in WRRFs.
- Specific aeration control, DO levels, and integration with EBPR are critical for inducing nitritation.
- Understanding microbial community dynamics at a molecular level is crucial for optimizing novel wastewater treatment processes like nitritation.
Keywords:
Ammonia-based aeration controlBiological nutrient removalEnhanced biological phosphorus removalMetabolomicsNitritationTranscriptomicsMore Related Videos
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