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Deciphering the dead zone on anammox system in biofilters
Yanjun Zhu1, Dong Li1, Jie Zhang2
1Key Laboratory of Water Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China.
Bioresource Technology
|November 11, 2024
Summary
Anammox biofilm reactors develop dead zones that reduce nitrogen removal. This study reveals how biofilms self-heal by altering microbial communities and gene expression, enabling long-term reactor application.
Area of Science:
- Environmental microbiology
- Wastewater treatment technologies
- Biofilm engineering
Background:
- Anammox (anaerobic ammonium oxidation) processes are crucial for nitrogen removal in wastewater treatment.
- Long-term operation of anammox biofilm reactors frequently results in localized dead zones (DZs), significantly impairing nitrogen removal efficiency.
- The underlying mechanisms driving dead zone formation and transformation in these systems remain poorly understood.
Purpose of the Study:
- To investigate the microbial community dynamics and self-healing mechanisms within anammox biofilm reactors experiencing dead zones.
- To elucidate the intrinsic reasons behind the transformation and impact of dead zones on reactor performance.
- To provide insights supporting the sustained application of anammox technology.
Main Methods:
- Classification of pilot-scale biofilters into biologically active zones (BZs), transition zones (TZs), and dead zones (DZs).
- Analysis of microbial community succession, particularly the accelerated changes observed in the transition zones.
- Investigation of biofilm responses to environmental stress, including alterations in signaling molecules and gene expression related to nitrogen removal.
Main Results:
- Microbial communities exhibit accelerated succession originating from the transition zones.
- Biofilms adapt to dead zone-induced stress by modifying signaling molecules, initiating cascading reactions.
- These reactions influence the abundance of nitrogen removal genes, enhance substance transformation, and expedite microbial community succession.
Conclusions:
- Anammox biofilms possess inherent self-healing capabilities in response to dead zone formation.
- Understanding these mechanisms, including microbial succession and gene regulation, is key to optimizing reactor performance.
- This research provides a foundation for improving the long-term stability and efficiency of anammox biofilm processes.
