Experimental determination of the dissolved oxygen boundary layer and mass transfer resistance near the fluid-biofilm interface

The thickness of the dissolved oxygen (DO) concentration boundary layer and the external mass transfer in a biofilm system were investigated using a microelectrode technique. Theoretical analysis was conducted to elucidate the mechanisms of the technique and to interpret the experimental measurement...

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Bibliographic Details
Published in:Water science and technology 1994-01, Vol.30 (11), p.47-58
Main Authors: Zhang, Tian C., Bishop, Paul L.
Format: Article
Language:English
Subjects:
Biofilms
Boundary layer
Boundary layers
Compression
Dissolved oxygen
Load distribution
Loading rate
Mass
Mass transfer
Oxygen
Roughness
Theoretical analysis
Thickness
Velocity
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Summary:The thickness of the dissolved oxygen (DO) concentration boundary layer and the external mass transfer in a biofilm system were investigated using a microelectrode technique. Theoretical analysis was conducted to elucidate the mechanisms of the technique and to interpret the experimental measurements. The measured thicknesses of dissolved oxygen (DO) concentration boundary layers under different conditions demonstrated directly the effect of several factors on external mass transfer resistance. The experimental results indicated that (a) increasing substrate loading rate, (b) increasing fluid streamwise velocity and (c) increasing the roughness of the biofilm surface would decrease the external mass transfer resistance. The measured thickness of the DO concentration boundary layer was not in full agreement with theoretical correlations because the nonuniform biofilm created velocity and concentration fluctuations which resulted in the compression of concentration boundary layers. The microelectrode technique is a useful tool to study the external mass transfer resistance.
ISSN:0273-1223
1996-9732
DOI:10.2166/wst.1994.0545