Patent ID: 7005069

Claim:
A wastewater treatment plant comprising: an aeration vessel having a bottom portion, a top portion and a side portion disposed therebetween to hold a quantity of wastewater, the top portion and the bottom portion being disposed at least 20 feet apart from one and the other to define a depth, the depth being capable of being substantially filled with wastewater, wherein the top portion encloses the aeration vessel to define a vapor space above the wastewater; a coarse bubble diffuser disposed proximal to the bottom portion, the diffuser having a plurality of orifices orientated horizontally toward the side portion; the orifices having a diameter of at least 0.125 inches; and a source of enriched oxygen gas in fluid communication with the diffuser, wherein the source of enriched oxygen-containing gas comprises a blower having an inlet gas flow and a outlet gas flow, the outlet gas flow being at higher pressure that the inlet gas flow, wherein the inlet gas flow comprises a first source of oxygen-rich gas having at least 90 mole percent oxygen and a second source of oxygen-rich gas having greater than 60 mole percent oxygen, the second source being from the vapor space; wherein the enriched oxygen gas exiting the orifices prevents settling of solid components of the wastewater without the use of a mechanical mixer.