Pure Oxygen Injection

Mazzei Pure Oxygen Injection Technology allows for smaller tanks and facilities

The use of pure oxygen, as opposed to air for the oxygen source, has been successfully employed in high-rate activated sludge wastewater treatment plants for many years. The primary advantage is the ability to sustain much higher oxygen uptake rates (OUR) than is possible using air due to the higher dissolved oxygen (DO) levels that can be maintained utilizing oxygen. The higher DO promotes much faster oxygen utilization by the activated sludge biomass as it consumes and stabilizes the BOD and nutrients in the influent. The result is effective treatment of wastewater in tanks/facilities that are typically much smaller in volume and footprint than an equivalent air-fed activated sludge plant.

Conventional pure oxygen WWTPs are typically closed-top multi-stage (usually four-stage) tanks. Each stage incorporates a shaft-driven low speed surface aerator and often a hydrofoil impeller to mix the bottom of the stage. Pure oxygen is fed into the headspace of the first stage where the low speed surface aerator contacts it with the wastewater. The headspace gas flows through the headspaces of the subsequent stages where it is further depleted of oxygen until the last stage where it is only about 40% oxygen, which is wasted to the atmosphere.

Subsurface injection of oxygen to the bottom of the tank where the head pressure of the water column facilitates higher oxygen solubility
Very high oxygen utilization rates
The ability to feed oxygen selectively into the various stages to optimize the treatment process
Very fine regulation of dissolved oxygen levels in the wastewater to prevent the growth of Nocardia microorganisms, which cause severe foaming problems in conventional pure oxygen plant configurations