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ASPAL Sludge Ozone based solution for sludge reduction

ASPAL™ Sludge

Ozone based solution for sludge reduction

How it works

ASPAL™ Sludge has been designed to reduce waste sludge at the source, where it is generated in the activated sludge treatment bio-basin. The system is based on a partial ozone treatment of the recycled activated sludge (RAS) and can reduce biosolid waste by 40%-70%. The system is offered on a turnkey basis with an oxygen tank, ozonation system and ozone contactor.

A portion of the RAS from the activated sludge treatment plant is sent to an ozone contactor where ozone, a powerful oxidizing agent, is dissolved in water to oxidize soluble organic or particulate matter.

Some of the the biomass is also oxidized (killed) in the process and  metabolized/ solubilized within the bio-basin (cell lysis) to become food for the remaining biomass.

The ozone is produced on-site from oxygen at a 10%-12% weight concentration and fed into the ozone contactor. The remaining oxygen from this process is recovered and sent back into the bio-basin for further oxygenation.


Air Liquide teams, drawing on years of expertise in wastewater treatment, have developed an innovative sludge reduction solution that improves sludge settling, reduces foaming, odors and volatile organic compound (VOC) emissions.

This solution contains all that you need: process know-how, industrial gases and innovative equipment.

Benefits of ASPAL™ Sludge solution:

  • Innovative solution with a low investment
  • Reusing oxygen in aeration with Turboxal™ or Ventoxal™ oxygen transfer equipment
  • Less filamentous, better settling and improved overall performance
  • Less excess sludge
  • Postponing or avoiding capital intensive debottlenecking

Contact our wastewater treatment specialist

Michel Epiney

514 949-6529

Send an email


Air Liquide offers services aimed at improving the performance of your wastewater treatment plant:

  • Auditing of your current aeration system's capacity
  • Estimate of your oxygen requirements
  • Pure oxygen injection or air enrichment solutions
  • Complete solution implemented within a few days
  • Oxygen storage system and transfer devices
  • Start-up and technical support


You will find below the list of industries for which  ASPAL Sludge ™  can be used to complement existing wastewater treatment.