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Excess nitrogen accumulation in activated sludge in sequencing batch reactor with a single-stage oxic process
Xiao-ming Li1, Dong-bo Wang, Qi Yang
1College of Environmental Science and Engineering, Hunan University, Changsha, People's Republic China. wwyy44339745@yahoo.com.cn
Summary
Nitrogen loss in wastewater treatment was investigated. The study found that excess nitrogen accumulation in activated sludge, not gaseous emissions, is the primary pathway for nitrogen removal in this system.
Area of Science:
- Environmental Science
- Environmental Engineering
- Microbiology
Background:
- Nitrogen loss in wastewater treatment can occur through various pathways.
- Understanding these pathways is crucial for optimizing nitrogen removal processes.
- Sequencing batch reactors (SBRs) are commonly used for wastewater treatment.
Purpose of the Study:
- To verify the phenomenon of nitrogen loss in a single-stage oxic SBR.
- To investigate the primary pathway of nitrogen removal under specific conditions.
- To quantify nitrogen accumulation in activated sludge and gaseous emissions.
Main Methods:
- Utilized a single-stage oxic sequencing batch reactor (SBR) with synthetic wastewater.
- Fed ammonia as the sole nitrogen source.
- Analyzed influent, effluent, off-gas, and activated sludge for nitrogen content.
- Performed nitrogen mass balance calculations.
Main Results:
- Effective nitrogen removal was achieved, with low levels of ammonia, nitrite, and nitrate in the effluent.
- A significant portion of influent nitrogen (95%) was lost from the solution, with minimal gaseous nitrogen increase (7%).
- Substantial nitrogen accumulation (84%) was observed in the activated sludge.
Conclusions:
- The primary pathway for nitrogen loss in this SBR system is nitrogen accumulation within the activated sludge.
- This finding highlights the importance of considering sludge biomass in nitrogen mass balance calculations for wastewater treatment systems.
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