N2 - Two types of submerged membrane bioreactors (MBR): hollow fiber (HF) and hollow sheet (HS), have been studied and compared in terms of energy consumption and average shear stress over the membrane wall. The analysis of energy consumption was made using the correlation to determine the blower power and the blower power demand per unit of permeate volume. Results showed that for the system geometries considered, in terms the of the blower power, the HF MBR requires less power compared to HS MBR. However, in terms of blower power per unit of permeate volume, the HS MBR requires less energy. The analysis of shear stress over the membrane surface was made using computational fluid dynamics (CFD) modelling. Experimental measurements for the HF MBR were compared with the CFD model and an error less that 8% was obtained. For the HS MBR, experimental measurements of velocity profiles were made and an error of 11% was found. This work uses an empirical relationship to determine the shear stress based on the ratio of aeration blower power to tank volume. This relationship is used in bubble column reactors and it is extrapolate to determine shear stress on MBR systems. This relationship proved to be overestimated by 28% compared to experimental measurements and CFD results. Therefore, a corrective factor is included in the relationship in order to account for the membrane placed inside the bioreactor.
L1 - http://journals.pan.pl/Content/94332/PDF/05_paper.pdf
L2 - http://journals.pan.pl/Content/94332
PY - 2012
IS - No 2 September
EP - 85-106
KW - Shear stress
KW - Bubble column
KW - CFD
KW - Membrane bioreactor (MBR)
A1 - Ratkovich, Nicolas
A1 - Bentzen, Thomas R.
A1 - Rasmussen, Michael R.
PB - The Committee of Thermodynamics and Combustion of the Polish Academy of Sciences and The Institute of Fluid-Flow Machinery Polish Academy of Sciences
T1 - Energy consumption in terms of shear stress for two types of membrane bioreactors used for municipal wastewater treatment processes
DA - 2012
SP - 85-106
UR - http://journals.pan.pl/dlibra/publication/edition/94332
T2 - Archives of Thermodynamics
DOI - 10.2478/v10173-012-0012-1