NOVEL BIOCHEMICAL OXIDATION SYSTEM

摘要

A surface aeration impeller (54) for use in a biochemical oxidation tank (22) . The impeller is rotatable about an axis perpendicular to the static liquid surface (37). The impeller has a plurality of blades (2) mounted on the underside of a disc or disclike surface (1). Each blade (2) has a multi-faceted or curved geometry ranging from vertical at the point of attachment to the disc to partially inclined at the bottom. The blades are spaced circumferentially about the axis (3) and are disposed at acute angles to radial lines from the axis of rotation of the impeller. The lower portions (7) of the blades, which are inclined but non-vertical, are positioned at or below the static liquid surface. When the impeller is rotated, the lower portion (7) pumps the liquid up onto the vertical portion (6) of the blades where the liquid is discharged into a spray umbrella (53, 55, 57) in a direction upwardly and outwardly away from the impeller. The design of the reinvention produces substantially higher oxygen transfer efficiency and overall liquid pumping rate than prior art designs and is particularly useful in the aeration of sewage an other wastewater.