Airjec® Diffuser

Replaces energy consuming high pressure aeration with low energy, low maintenance diffuser


The Airjec Diffuser is a unique device for the formation of air micro-bubbles to replace conventional pressurized vessel aeration systems on flotation water clarifiers.

A relatively small flow of water is used to kinetically draw in air by suction from the surrounding atmosphere. The configuration of the mixing chamber is designed to form a bubble size distribution ideally suited to particle flotation.

Aeration Principle


Dissolved air systems are governed by the physics of air solubility in water. High flows of  water at high pressure are needed, requiring significant energy for the water pump and also the air compressor. Under ideal conditions 1 cubic metre of clean water at 5 bar and at 30° C will only dissolve 100 litres of air.

Additionally, the air solubility is dependent on a number of factors including temperature and water quality; meaning that poor quality clarified water can cause further flotation issues.

Airjec Diffuser

The Airjec uses the kinetic energy of the water flow to draw in air and disperse it as micro-bubbles. This removes the constraint of air solubility; increasing dramatically the air carrying capacity of the water stream. Typically 1 cubic metre of clean water will carry 4 000 litres of air.

The kinetic energy of the water is independent of water quality; so, within some constraints, the aeration is not effected by suspended solids. This means that aeration is not reliant on good water quality removing the escalation of poor operation.

The system is designed to generate bubbles that are ideally suited to solids separation in clarifiers.

Feature Customer Benefit
Kinetic energy is used to draw in air. Lower energy required lowering operating costs significantly.
No air compressor needed.
Bubble-size distribution optimized for flotation. Improved water quality.
Better sludge density and consistency.
Improved aeration has shown lowering of COD measurements Lower organic load recycling in system.
Potential down-stream cost reductions
Lower aerated water volume Smaller water pump consuming less energy.
Lower water pressure Lower pump wear – less maintenance.
Aeration is not dependent on water quality. Stability of system is improved.
Clarifier Untreated Feed can be used increasing hydraulic capacity by up to 30%
Straight forward installation Quick to gain results.
No moving parts in Airjec Low maintenance and high durability.
System is more controllable Less operator dependence.
No large pressure-vessel No requirement for insurance inspection
Space saving
Chemical injection through unit Improvement in polymer distribution.
Better chemical action.
Water dilution savings.

There are more than 200 Airjec Units installed in Europe.


The Airjec Diffuser is supplied by RITHCO® Papertec.
Castor HR Consulting Ltd is the sole agent in UK and Ireland