Vatten behandling

Why treat wastewater before discharge into the natural environment?

Whether the water is used domestically (by the inhabitants) or industrially, it must be treated in a treatment plant before being discharged into the natural environment (in Paris, most often, we are talking about the Seine). Indeed, the organic matter contained in untreated water could harm aquatic fauna and flora (fish, algae, etc.). Once treated, discharges from wastewater treatment plants are not necessarily drinkable, but are adapted to the natural environment. The bacteria and particles present in domestic water have as a measure, in large and small agglomerations, an equivalent/inhabitant (in millions).

Along with the gases used, the equipment plays a key role in reducing sewage treatment plant sludge, foam and odours. Our strength also lies in the quality of the equipment and products designed by Air Liquide and made available to you for use in your treatment and sanitation process.

Your equipment to regulate the injection of oxygen, CO2  and ozone into your wastewater treatment plant

The injection of oxygen into the aeration basins makes it possible to increase the purification performance of biological wastewater treatment plants. To eliminate dissolved organic matter and other matter and discharges in suspension (waste) present in the basins, you have tailor-made and efficient equipment:  

TURBOXAL® for surface oxygenation.
VENTOXAL® for underwater oxygenation.

For wastewater treatment plants with lower flow rates and smaller capacity basins, Air Liquide offers you the following unique wastewater treatment devices, at the peak of technology and efficiency to cater for a variety of consumption profiles:

BICONE® for surface oxygenation.
POROXAL® for submerged oxygenation.


Equipement - injecteur Turboxal


A powerful and compact floating oxygen-transfer system, the Oxy Injector-Turboxal delivers high- performance oxygenation of wastewater in biological basins and lagoons.

Through Air Liquide’s patented system, wastewater and oxygen are thoroughly mixed by a specific turbine in the biomass. The effluent is then dispersed downwards via a powerful impeller, ensuring efficient oxygen transfer to the wastewater.

The Oxy Injector-Turboxal is suitable for treating varying pollution levels without shear stress that could impair the biomass efficiency.
For the denitrification step, Oxy Injector-Turboxal  is able to mix the basin without gas injection.

Its advantages :

  • Well-suited for varying pollution levels
  • High oxygen transfer rate
  • Very easy installation
  • Distinctly low maintenance
Oxy Injecteur-Ventoxal


A dynamic gas-injection device designed by Air Liquide, the Oxy Injector-Ventoxal system significantly increases the mass-transfer rate to reach high oxygen dissolution, and it integrates seamlessly with all types of wastewater basins.

The water that needs to be treated is pumped through a gas-liquid nozzle where oxygen is introduced. Emerging gas bubbles burst quickly, resulting in a highly dispersed fine-bubble stream. The oxygen-enriched fluid is then injected, thus enhancing overall oxygenation and mixing. During process steps where no oxygen is needed, the system provides the required mixing energy (e.g. for the denitrification step, the Oxy Injector-Ventoxal is able to mix the basin without gas injection).

The system can be adapted to wastewater basins with varying water depths and levels of pollution. The combination of mixing and high oxygen transfer makes it a powerfully effective solution.

Its advantages :

  •     High oxygen transfer rate
  •     Well-suited for high pollution levels
  •     Easy installation
  •     Distinctly low maintenance
Injecteur POROXAL


The POROXAL® injector, submerged at the bottom of the basin, treats wastewater by injecting oxygen. It is also suitable for dissolving carbon dioxide (CO2 ) to reduce pH.

Its advantages:

  • Works without agitator,
  • High injection capacity: up to 35 kg/hour, in deep biological basins (> 5 meters),
  • Prevents an oxygen deficit in biological ponds, caused by the feeding of bacteria to eliminate organic matter (suspended or dissolved matter) and/or an overdose,
  • Ease of installation and maintenance: no need to empty the basins.
Injecteur Bicone


The BICONE® injector is able to dissolve different gases such as carbon dioxide (CO  ), oxygen (O2 ) and ozone (O3 ) in water at the saturation limit.

Its advantages :

  • Dissolves oxygen in water up to 78 kg/hour depending on the model,
  • Economical static mixer,
  • Ensures high gas enrichment efficiency with minimal hydraulic loss at all stages,
  • Technology particularly effective in water from industries (process water), where the solubility of the gas is limited by the operating conditions.
OZONE injection system


A flexible equipment designed by Air Liquide, the OZONE INJECTION SYSTEM is well suited to produce and dissolve ozone into water. It encompasses one gas control panel and one gas distribution panel along with an ozone injection and safety control system. On request, we include a pure-oxygen-fed ozone generator or integrate yours into the equipment.

An OZONE INJECTION SYSTEM is typically part of the following installation:

  • A liquid-O2 storage tank with filling/withdrawal lines and necessary instrumentation for safe operation.
  • A vaporizer to vaporize the liquid O2 to gaseous state.
  • • A gas control panel mounted in the gas pipeline after vaporization to feed the ozone generator which can be cooled down using the cooling power of the liquid-O2 vaporization, thus saving the usage of cooling water.
  • A gas distribution panel with the proper amount of gas at the appropriated pressure to feed the ozone injectors in the ozonation chamber.
  • An ozone gas detector to control safety in the ozone production area.


As regulatory requirements have evolved, new ozone-based water treatments have emerged. And since each ozone application is specific to water pollutants, Air Liquide always conducts thorough pre-analysis to determine the optimal ozone dosage for discharge limits without side effects. We then perform sizing calculations to design an ozone plant installation made up of three modules:

  • Ozone production unit
  • Injection and pumping unit
  • Reaction and safe off-gas decomposition unit

Using our patented OXY INJECTOR-TURBOXAL system or OXY INJECTOR-VENTOXAL system, the oxygen-rich off-gas from the OZONATION UNIT can be recovered at atmospheric pressure and re-used to make up for oxygen injection in upstream or downstream biological basins.

Special Features

Ozone is easily soluble in aqueous liquids and oxidizes all compounds very rapidly. Thanks to its advanced design, the OZONATION UNIT leaves less than 0.5% ozone in exhaust gas. The operating conditions (e.g. pH, temperature, flow rates, cleaning cycles, etc.), are set in order to focus the ozone efficiency on breaking down the targeted pollutants.

Do you have any questions about equipment for waste water treatment?

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