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Nitrogen removal from sewage by continuous flow SBR system with intermittent aeration
1Department of Environmental System Engineering, Nagaoka University of Technology, Kamitomioka 1603-1, Nagaoka, Niigata 940-2188, Japan.
Environmental Technology
|June 27, 2001
Summary
The intermittent cycle extended aeration system (ICEAS) effectively removes nitrogen from sewage. Optimizing dissolved oxygen and MLSS in ICEAS achieved up to 94.9% total nitrogen removal, offering an economical wastewater treatment solution.
Area of Science:
- Environmental Engineering
- Wastewater Treatment
- Nitrogen Removal
Background:
- Conventional intermittent cycle extended aeration systems (ICEAS) show high COD removal but struggle with high nitrate levels and low pH in effluent.
- Intermittent aeration in ICEAS reduces dissolved oxygen, leading to partial ammonia oxidation to nitrite, with some nitrate present in the effluent.
Purpose of the Study:
- To investigate the nitrogen removal efficiencies of a continuous-flow sequential batch reactor using intermittent aeration (ICEAS).
- To optimize ICEAS parameters for enhanced nitrogen removal in synthetic sewage wastewater treatment.
Main Methods:
- Utilized a continuous-flow sequential batch reactor system with intermittent aeration (ICEAS).
- Conducted experiments under varying dissolved oxygen (DO) levels and mixed liquor suspended solids (MLSS) concentrations.
- Analyzed ammonia, nitrite, and nitrate levels in the effluent under different operational cycles.
Main Results:
- Intermittent aeration led to lower dissolved oxygen (0.5-1.2 mg l-1) compared to continuous aeration (3.5-5.0 mg l-1).
- Higher oxidation rates of ammonia to nitrite (1.44-3.55 mg N g-1 MLSS hr-1) were observed than nitrite to nitrate (0.00-1.22 mg N g-1 MLSS hr-1) under low DO conditions.
- A total nitrogen removal rate of up to 94.9% was achieved with MLSS at 3200 mg l-1 and low DO.
Conclusions:
- Denitrification rates in ICEAS were not significantly limited by the low supplement of soluble organic carbon.
- The intermittent aeration process in ICEAS offers an economically viable and effective method for nitrogen removal in sewage treatment.
- Optimized ICEAS operation, particularly low DO and controlled MLSS, is crucial for maximizing nitrogen removal efficiency.
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