Scale-up formulations for radial and pitch blade surface aerators for oxygenation capacity and power requirements

This investigation is concerned with the development of scale-up equations for oxygenation capacity and power requirement for radial and pitch blade surface aerators. Variables include the aerator diameter, number and size of blades, together with submergence and depth of water. In the case of the pitch blade aerator, an additional variable has been added: the angle of blades. After deaeration had been completed, the dissolved oxygen level was measured as a function of time and hence the mass transfer coefficients, oxygenation capacities and oxygenation efficiencies were determined. In all the tests, it was found that the oxygenation capacity was enhanced by increased rotational speed, tank size, number of blades, and aerator diameter and optimum values of the speed, submergence and angle of blade were indicated. Empirical correlations of data, specific to the systems investigated, have been made and it may be that these are applicable to other aerator designs, data on which are sadly lacking.