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Microbial community characteristics during simultaneous nitrification-denitrification process: effect of COD/TP ratio
Jian Zhang1, Wenlin Jia2, Rong Wang1
1Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan, 250100, China.
Environmental Science and Pollution Research International
|October 3, 2015
Summary
The chemical oxygen demand (COD) to total phosphorus (TP) ratio significantly impacts microbial communities in low-oxygen simultaneous nitrification and denitrification. Lower COD/TP ratios favor phosphorus-accumulating organisms, crucial for wastewater treatment efficiency.
Area of Science:
- Environmental Science
- Microbiology
- Environmental Engineering
Background:
- Simultaneous nitrification and denitrification (SND) is vital for wastewater treatment.
- Optimizing SND processes requires understanding microbial community responses to nutrient ratios.
- The influence of chemical oxygen demand (COD) to total phosphorus (TP) ratios on low-oxygen SND is not fully elucidated.
Purpose of the Study:
- To investigate the effect of varying COD/TP ratios on microbial community structure during low-oxygen SND.
- To identify key microbial groups influenced by different COD/TP ratios in sequencing batch reactors (SBRs).
Main Methods:
- Three anaerobic-aeration SBRs (R1, R2, R3) were operated at distinct COD/TP ratios (91.6, 40.8, 27.6).
- Molecular biological techniques were employed to analyze microbial community structures.
- Shannon indexes were used to assess the diversity of ammonia-oxidizing bacteria (AOB).
Main Results:
- The COD/TP ratio significantly affected the composition of ammonia-oxidizing bacteria (AOB), as indicated by Shannon indexes.
- Nitrosomonas emerged as the dominant AOB species across all tested SBRs.
- The abundance of nitrifiers exceeded that of denitrifiers.
- An increasing ratio of phosphorus-accumulating organisms (PAOs) to glycogen-accumulating organisms (GAOs) was observed as the COD/TP ratio decreased.
Conclusions:
- The COD/TP ratio is a critical factor regulating microbial community dynamics in low-oxygen SND processes.
- Lower COD/TP ratios promote the proliferation of PAOs, enhancing biological phosphorus removal.
- Understanding these microbial shifts is essential for optimizing SND performance in wastewater treatment.
Keywords:
COD/TP ratioMicrobial communityMolecular biological techniqueSimultaneous nitrification and denitrificationMore Related Videos
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