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DGI™ Dissolved Gas Infusion

Blue dropDGI™ Dissolved Gas Infusion Technology

Oxygen Aeration

DGI Technology from Fuel Tech offers an innovative alternative to current aeration technologies. Utilizing a patented, high-velocity nozzle, clouds of micro and nano bubbles are infused into water/wastewater to optimize:

  • Environmental remediation
  • Aerobic digestion
  • Biological treatment


DGI Nozzle and CFDBased on decades of experience in process engineering and system deployment, Fuel Tech is uniquely positioned to advance gas infusion technology for these applications. Expertise in chemical treatment, injection technologies, and computational fluid dynamics, combined with equipment and process design, allow further development of innovative solutions for industrial water treatment.




 Video: Mobile Treatment System

The Advantages of Micro/Nano Bubbles

Bouyancy diagramLarger bubbles have a greater buoyancy factor and rise rapidly through a water column, requiring a greater depth for tanks, vessels, and lagoons to provide the retention time required for oxygen transfer.

Bubble size comparison chart


DGI systems create bubbles in the range from a few nanometers (nm) to micrometers (μm). A bubble less than one micron in diameter doesn’t have a determinable rise velocity because of its low buoyancy and the effects of Brownian motion. The smaller bubbles result in a reduced rise rate, increased surface area, increased residence time, and minimal losses.

The Process

The DGI process utilizes a pressure vessel that is fed using a slip stream of raw or pre-treated water. Oxygen is introduced to the top of the pressure vessel, pressurizing the header space to the operating range of 150-300 psi. The gas is driven into the liquid according to Henry’s Law.

The source water for this carrier fluid is filtered to remove suspended solids larger than 25 microns.
Depending on the composition of the water, other filtration methods may be required.

The gas-laden carrier fluid then exits the bottom of the pressure vessel where it is delivered to one or more zones of injection and discharged into the water/wastewater to be treated through the injector nozzle. The bubble size is controlled through the system pressure and injector design. This design is optimized through the use of Fuel Tech’s CFD and modeling expertise.

Sensors in the treatment zones measure dissolved oxygen. In turn, the volume oxygen is adjusted automatically by controlling pressure in the headspace of the infusion vessel.

System sizing varies and depends on many factors. These can include desired final dissolved oxygen levels, required treatment time, wastewater inlet rate, the reduction of one or more contaminants to a target concentration, or seasonal variances. Consult with Fuel Tech to discuss these options.


DGI Features & Benefits

  • Operating costs up to 50% lower than conventional aeration
  • Modular, compact, scalable systems for rapid deployment
  • System can maximize and control dissolved oxygen levels


  • Treating 10% of wastewater volume can provide 100% treatment
  • Nozzles accessible at edge of basin or lagoon for maintenance

Equipment Overview

DGI 15gpm system labels

The DGI Technology platform supplied as a fully integrated system. Skidded and modularized to the greatest extent possible, the system is designed for rapid deployment to site and simple installation.


System Components

  • Infusion pressure vessel
  • Oxygen generator or cylinders for testing / demo and small systems
  • Pre-filtration system
  • Control panel
  • Custom DGI nozzles

 DGI Industries


  • Power Generation
  • Oil & Gas
  • Pulp & Paper
  • Chemical
  • Steel
  • Other Industrial


  • Flowback/Produced Water Storage Treatment
  • Oil-Water Separation
  • Industrial Aeration Upgrades 
  • TSS (Total Suspended Solids) Removal
  • Sludge Lagoon Treatment 
  • Oxidation Reduction Potential (ORP
  • Algae Bloom Remediation/Avoidance 
  • Nutrient Removal 
  • H2S Abatement & Odor Control


Water Technologies Literature