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Biological nitrogen and phosphorus removal in UCT-type MBR process
Hansaem Lee1, Jonghun Han, Z Yun
1Department of Environmental Engineering, Korea University, Seongbuk-gu, Seoul 136-713, South Korea. lhs1351@korea.ac.kr
Summary
This study shows that optimizing carbon source allocation in membrane bioreactors (MBRs) is crucial for effective biological nutrient removal (BNR). Step feeding improved nitrogen and phosphorus removal by supporting denitrifying phosphorus accumulating organisms (dPAOs).
Area of Science:
- Environmental Engineering
- Microbiology
- Wastewater Treatment
Background:
- Biological nutrient removal (BNR) is essential for wastewater treatment.
- Membrane bioreactors (MBRs) offer efficient solutions for BNR.
- UCT-type MBRs are investigated for simultaneous nitrogen (N) and phosphorus (P) removal.
Purpose of the Study:
- To evaluate the BNR performance of a lab-scale UCT-type MBR with varying wastewater strengths.
- To identify factors affecting simultaneous N and P removal.
- To optimize MBR operation for enhanced nutrient removal.
Main Methods:
- Operation of a lab-scale UCT-type membrane bio-reactor (MBR).
- Feeding with synthetic strong and weak wastewater.
- Implementation of step feed modification.
- Analysis of nutrient removal efficiencies and specific phosphorus uptake rates.
Main Results:
- Simultaneous N and P removal was achieved with strong wastewater.
- Weak wastewater led to decreased N and P removal, potentially due to nitrate inhibition.
- Step feeding with weak wastewater restored N and P removal capabilities.
- Denitrifying phosphorus accumulating organisms (dPAOs) contributed significantly to P removal (up to 40%).
Conclusions:
- Effective carbon source allocation (COD) for denitrification in the anoxic zone is key for enhancing biological phosphorus removal in UCT-type MBRs.
- dPAOs play a vital role in simultaneous N and P removal.
- UCT-type MBRs exhibit sludge production similar to conventional activated sludge systems with BNR.
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