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Electrochemically and Bioelectrochemically Induced Ammonium Recovery
Published on: January 22, 2015
Nitrogen removal during secondary treatment by aquatic systems
B Erol Nalbur1, L Akça, H Bayhan
1Uludağ University, Department of Environmental Engineering, Bursa, Turkey. berrak_erol@yahoo.com
Summary
Duckweed (Lemna minor) reactors effectively remove nitrogen during wastewater treatment. Optimal performance was achieved with specific hydraulic and mass loading rates, demonstrating their importance over retention time.
Area of Science:
- Environmental Engineering
- Wastewater Treatment Technologies
- Aquatic Plant Systems
Background:
- Domestic wastewater treatment requires efficient nitrogen removal to prevent eutrophication.
- Duckweed (Lemna minor) has shown potential for nutrient removal in aquatic systems.
- Understanding loading parameters is crucial for optimizing biological treatment processes.
Purpose of the Study:
- To investigate nitrogen removal efficiency in duckweed reactors for secondary wastewater treatment.
- To evaluate the impact of hydraulic retention time, hydraulic loading rate, and mass loading rate on nitrogen removal.
- To determine optimal loading conditions for duckweed-based nitrogen removal.
Main Methods:
- Two lab-scale duckweed (Lemna minor) reactors were used.
- Measurements of Total Kjeldahl Nitrogen (TKN), ammonia nitrogen (NH3-N), and nitrate nitrogen (NO3-N) were taken.
- Analysis was conducted across a range of hydraulic retention times (3.3 to 23 days) and loading rates.
Main Results:
- Hydraulic and mass loading rates were more significant than hydraulic retention time for nitrogen removal.
- Optimal hydraulic loading rate was 1.2 cm/day, and mass loading rate was 90-160 mg TKN/m2-day.
- Effluent TKN and NH3-N concentrations were low (2.5-3.0 mg/l and near zero, respectively) at optimal conditions, with NO3-N between 7-11 mg/l.
Conclusions:
- Duckweed reactors are effective for secondary wastewater treatment, particularly regarding nitrogen removal.
- Hydraulic and mass loading rates are critical parameters for optimizing duckweed pond performance.
- Nitrogen conversion primarily occurs in the initial sections of the reactor, highlighting the importance of inlet conditions.
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