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Comparing two hydrazine addition strategies to stabilize mainstream deammonification: Performance and microbial
1State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
Bioresource Technology
|July 7, 2019
Summary
Adding hydrazine (N2H4) to an expanded granular sludge blanket reactor (EGSB) stabilized deammonification. Variable hydrazine concentration (strategy B) enhanced nitrogen removal efficiency and favored microbial diversity.
Area of Science:
- Environmental Science
- Microbiology
- Chemical Engineering
Background:
- Deammonification processes are crucial for wastewater treatment.
- Inhibiting nitrite oxidizing bacteria is key to achieving stable deammonification.
- Hydrazine (N2H4) has been explored as an inhibitor in deammonification.
Purpose of the Study:
- To investigate the efficacy of hydrazine addition for stable mainstream deammonification.
- To compare constant (strategy A) versus variable (strategy B) hydrazine concentration methods.
- To analyze the impact of hydrazine on microbial communities and deammonification performance.
Main Methods:
- Utilized an expanded granular sludge blanket reactor (EGSB).
- Implemented two hydrazine addition strategies: constant concentration (A) and variable concentration (B).
- Monitored nitrogen removal efficiency, nitrogen removal rate, and microbial community composition.
Main Results:
- Strategy B achieved higher total nitrogen removal efficiency (82 ± 6%) and nitrogen removal rate (0.32 ± 0.02 kg N/(m3·d)).
- Hydrazine inhibited anaerobic ammonia oxidizing bacteria (AnAOB) activity under strategy A.
- Candidatus Brocadia abundance increased under strategy B, suggesting a self-regulation mechanism.
- Aerobic ammonia oxidizing bacteria (AOB) and AnAOB remained dominant.
- Strategy B fostered a more diverse microbial environment.
Conclusions:
- Variable hydrazine concentration (strategy B) is superior for stable mainstream deammonification.
- Hydrazine effectively inhibits nitrite oxidizing bacteria, enhancing deammonification performance.
- The study highlights the importance of microbial community dynamics in deammonification processes.
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