An LHO (Low Head Oxygenator) oxygenates water at low hydraulic head. Water is distributed over chambers or packing where oxygen (or oxygen-enriched gas) contacts the water without needing the high pump pressures of a deep oxygen cone. That makes LHOs energy-efficient in many RAS designs.
Advantages
- Low head → lower pumping energy than a high-pressure cone.
- Good oxygen transfer with pure O₂ when designed correctly.
- Can be built into process-floor hydraulics.
Limitations and risks
- Needs even water distribution across chambers.
- Wrong gas balance can cause N₂ supersaturation or poor O₂ utilisation.
- Packing/chambers must be kept clean of biofilm and solids.
- Not always right for very high ΔDO — sometimes a cone or complementary dosing is needed.
In the oxygen strategy
Many facilities first maximise air-side uptake in degassers/trickling, then use an LHO or cone for the final O₂ boost. See degassers, oxygen cones and oxygen demand.
See also