Treatment of civil and industrial wastewater with pure oxygen

Biological treatment of wastewater is a purification process that also occurs in nature and uses live aerobic bacteria to digest pollutants, thus purifying wastewater. Compared to what happens in nature with often very slow processes, in purification plants very high concentrations of active biomass (biological sludge) are artificially maintained, which are kept alive by a forced injection of oxygen through various systems. In the table below we can see what the oxygen dissolution yields are through different types of microbubble diffusers, through surface turbines or submerged aerators.

All the aeration systems mentioned above are characterized by a modest transfer of oxygen to the wastewater to be treated depending on the amount of energy consumed as can be seen in the table above.

On the contrary, oxygenation systems operating with total pure oxygen can transfer up to 4 times more oxygen for the same amount of energy consumed … but …. You have to pay for the oxygen consumed! Nonetheless, the advantages resulting from the use of total pure oxygen are such as to make the application of this technology convenient.

Here are the most obvious advantages:

• Increased capacity for treating the polluting load

Thanks to the ability to transfer a greater quantity of oxygen with less energy and in the same volume, the use of oxygen can increase the treatment capacity of the purifier up to over 50% of the original capacity

• Savings on investments

By taking into account the adoption of pure oxygen technology from the design stage, it will be possible to think of smaller biological treatment tanks equipped with oxygenation systems that will use less electricity, making it possible to reduce the energy commitment dedicated with a great advantage on the electricity bill.

• Savings on operating costs

Precisely for what was explained in the previous point, it is easy to imagine that the drastic reduction in electricity consumption is due to both fixed costs linked to the lower energy commitment with the supplier, and consumption over time, knowing that these systems are generally active 24/24x 365 days.

• Reduction of surface foams

The oxygenation of the biological activated sludge flake is improved thanks to the greater concentration of oxygen in contact with the sludge itself; as a result, the filamentous bacteria are eliminated and the flakes become more compact. As a result, the sedimentation of the sludge improves, avoiding foam and flotation on the surface of the settler.

• No odors thanks to the reduction of aerosols

Thanks to the fact that at least 93-95% of the injected oxygen will be dissolved in the wastewater and the lack of nitrogen present in the air in standard aeration systems, a 97% reduction in gaseous emissions due to stripping will be obtained. The consequence is the total disappearance of odors in the purifier area.

At this link you can download our SICODEP™ brochure dedicated to this important application.