Abstract: A system for treating wastewater includes a basin to contain wastewater, an aerator provided in the basin to mix the wastewater, and a cover system to cover a surface of the wastewater contained in the basin. The cover system includes a plurality of hollow bodies disposed on the surface of the wastewater. Each hollow body is adapted to float on the wastewater's surface, and has a contiguous outer surface and a sufficient mass so that 30 to 70 percent of the hollow body's outer surface is exposed to atmosphere during use. A method of treating wastewater is further disclosed.

Abstract: A system for treating wastewater includes a basin to contain wastewater, an aerator provided in the basin to mix the wastewater, and a cover system to cover a surface of the wastewater contained in the basin. The cover system includes a plurality of hollow bodies disposed on the surface of the wastewater. Each hollow body is adapted to float on the wastewater's surface, and has a contiguous outer surface and a sufficient mass so that 30 to 70 percent of the hollow body's outer surface is exposed to atmosphere during use. A method of treating wastewater is further disclosed.

Abstract: A floating mixer which is suitable for use in anoxic processes in wastewater treatment facilities is provided. The mixer includes a float and a motor having an elongated shaft which is carried on the float such that the shaft extends into the body of liquid. A motor base is also carried by the float and it supports a shaft enclosure which surrounds and protects the shaft. When the mixer is floating in a body of liquid, the upper end of the shaft enclosure is in communication with the atmosphere above the surface of the body of liquid and the lower end of the shaft enclosure is in communication with the body of liquid. The mixer further includes a propeller attached to the drive shaft below the surface of the liquid which, when driven by the motor, creates a low pressure zone which extends to the lower end of the shaft enclosure.