Structure of Turbulence and Oxygen Transfer Mechanism
443
K L *a= Overall oxygen absorption coefficient.
The overall oxygen absorption coefficient "K L *a" is usually used as an effective
measure to evaluate the efficiency of aeration.
One purpose of this paper is to reconsider the effects of the "micro-turbulence" and to
find quantitative relations among the various phenomena observed.
For this purpose, two series of experiments were conducted. One (series C) was to
examine the extent of the effects of turbulence in which differences of power spectrum
were already identified in series A and B. The other (series D) was to examine the effects
of the suspended solids concentration and of the kinds of solids.
Experimental Apparatus and Procedure
Pen
Recorded
DO
Meter
» — - i
SL.
Oxygen
Cencer
W
Air or
N2 Gas
10.0cmFig. 7.
Experimental Vessel of Series D
Aeration system: In series C, the apparatus was as shown in Fig. 1. In series D, a
cylindrical vessel with an agitation paddle was used as shown in Fig. 7. The oxygen sensor
was a galvanic cell type oxygen analyzer.
Procedure: Oxygenation by air followed deoxygenation by N 2 gas. The oxygen
concentration was recorded on a pen recorder. The overall coefficient "K L *a" was