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[Nitrogen Removal of Double-bacteria-layer System via PN/A Process]
Jing-Yi Xu1, Jun Du1, Yi-Feng Yang1
1College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
Huan Jing Ke Xue= Huanjing Kexue
|July 13, 2018
Summary
A novel PN/A double-bacteria-layer system efficiently removes ammonia nitrogen (NH4+-N) using immobilized nitrification and anaerobic ammonia oxidation (ANAMMOX) sludge. This system enhances stability and nitrogen removal, even with limited dissolved oxygen (DO).
Area of Science:
- Environmental Science
- Microbiology
- Chemical Engineering
Background:
- Wastewater treatment often faces challenges with efficient nitrogen removal.
- Simultaneous nitrification and anaerobic ammonia oxidation (SNA) processes require optimized microbial consortia and reactor configurations.
- Microbial immobilization is a key technology for enhancing the performance of wastewater treatment systems.
Purpose of the Study:
- To develop and evaluate a novel PN/A double-bacteria-layer system for enhanced nitrogen removal.
- To investigate the roles of ammonia-oxidizing bacteria (AOB) and ANAMMOX bacteria in the system.
- To assess the system's performance under varying influent conditions and limited dissolved oxygen (DO).
Main Methods:
- Acclimation of nitrification and ANAMMOX sludge using Sequencing Batch Reactor (SBR) and Membrane Bioreactor (MBR) respectively.
- Construction of a PN/A double-bacteria-layer system with microbial immobilization.
- Short-term and long-term experiments to evaluate nitrogen removal efficiency, stability, and DO utilization.
Main Results:
- The PN/A system achieved 98.8% NH4+-N removal in short-term tests, with distinct roles for AOB and ANAMMOX bacteria.
- Stable nitrogen removal efficiency of ~80% was maintained at low DO levels (1.0 mg·L-1) with influent NH4+-N concentrations of 200-400 mg·L-1.
- Compared to the control, the PN/A system showed significantly higher nitrogen removal efficiency under limited DO conditions.
Conclusions:
- The PN/A double-bacteria-layer system effectively integrates nitrification and ANAMMOX processes for superior nitrogen removal.
- Microbial immobilization and the double-bacteria-layer design enhance DO utilization and system stability.
- This innovative system offers a promising solution for efficient and stable removal of ammonia nitrogen in wastewater treatment.
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