Vertical counterflow sludge aeration - lengthens air bubble retention by impeller induced flow opposite to air jet flow

摘要

The Parent Patent described on aeration system for an activated sludge treatment in which an impeller was mounted inside an impeller tube above an air distributor which directs air jets towards the bottom of the basin. If the direction of rotation of the impeller is such that it produces an upward water flow in the impeller tube, this creates a downward flow between basin wall (1) and tube and retains the air bubbles longer. To achieve the best effect, the cross-section of the annulus should equal that of the tube.