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Biomass effects on oxygen transfer in membrane bioreactors
1School of Applied Sciences, Cranfield University, Cranfield BEDS, MK43 0AL, UK.
Water Research
|January 16, 2007
Summary
Mixed liquor suspended solids concentration (MLSS) is the primary factor controlling oxygen transfer in membrane bioreactors (MBRs). Higher MLSS, along with EPS(c) and aeration, improves oxygen transfer, while SMP(COD) hinders it.
Area of Science:
- Environmental Engineering
- Biotechnology
- Wastewater Treatment
Background:
- Submerged membrane bioreactors (MBRs) are crucial for efficient wastewater treatment.
- Understanding factors affecting oxygen transfer in MBRs is vital for optimizing performance.
- Biomass characteristics significantly influence oxygen transfer rates.
Purpose of the Study:
- To investigate the impact of various biomass characteristics on oxygen transfer in MBRs.
- To determine the relative importance of solids concentration, EPS(c), and SMP(COD) on oxygen transfer parameters.
- To identify key parameters controlling oxygen transfer for improved MBR operation.
Main Methods:
- Analysis of ten biomass samples from municipal and industrial pilot and full-scale MBRs.
- Experimentation across six different air-flow rates.
- Statistical analysis to correlate biomass properties with oxygen transfer coefficients (k(L)a(20)) and alpha-factors.
Main Results:
- Solids concentration (MLSS), carbohydrate fraction of extracellular polymeric substances (EPS(c)), and chemical oxygen demand of soluble microbial products (SMP(COD)) significantly affect oxygen transfer.
- MLSS was identified as the dominant factor influencing oxygen transfer.
- Oxygen transfer parameters (k(L)a(20) and alpha-factor) increased with aeration and EPS(c) but decreased with higher MLSS and SMP(COD).
Conclusions:
- Mixed liquor suspended solids concentration is the primary determinant of oxygen transfer efficiency in MBRs.
- Optimizing MLSS, EPS(c), and aeration while managing SMP(COD) can enhance oxygen transfer.
- This research provides critical insights for the design and operation of MBR systems.
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