| Abstract: | ![]()
The authors have investigated a special aspect of the transfer of oxygen: the aeration performance of small-scale suction-impellers in a suspension of activated sludge floes and a performance comparison with clear water. The principle of the impellers is, that in order to disperse air bubbles into the aforementioned liquids, all that we need do is a simple stirring. Due to the impellers the authors could not show a reduction of the oxygen transfer coefficient in the presence of sludge flocs. Former comparative studies of oxygen transfer, using a fixed orifice, did show a reduction in the presence of sludge flocs. Therefore, it seems probable that the effect of activated sludge flocs on the transfer coefficient is linked with the manner in which air is dispersed, i.e., depends on whether an orifice is fixed or moved. The experimental results allow presumption that by developing a high intensity of shear near the location where air bubbles are produced, we are able to minimize the effect of sludge flocs on the process of bubble formation. |
