Different Tools, Different Jobs
UV and ozone both support biosecurity, but they are not interchangeable. UV is primarily a single-pass disinfection tool. Ozone is useful for oxidizing dissolved organics, improving water clarity, supporting pathogen reduction, and increasing UV effectiveness, but it introduces residual safety risk if not controlled.
UV Design Considerations
UV performance depends on dose, water clarity, flow rate, sleeve cleanliness, lamp condition, and reactor hydraulics. A UV unit can be installed and still underperform if water bypasses lamps or quartz sleeves foul.
Key checks include:
- Correct dose for the target risk profile
- Flow matched to reactor capacity
- UV transmittance considered in water quality assumptions
- Quartz sleeve cleaning and lamp replacement schedule
- Reactor design that reduces channeling
Ozone Design Considerations
Ozone should be controlled by ORP, contact time, water quality, and residual destruction. It should never be allowed to reach culture tanks at harmful concentrations.
Critical design elements include:
- ORP monitoring with calibration routines
- Contact chamber sized for the treatment goal
- Off-gas management
- Activated carbon or catalytic destruction for residual ozone
- Alarm logic that stops dosing when ORP or flow conditions are unsafe
Common Failure Modes
- ORP probe drift creating false confidence
- Ozone residual passing through failed carbon treatment
- Overdosing during low-flow conditions
- UV sleeve scaling reducing dose
- Using ozone to compensate for poor solids removal
Practical Integration
Ozone and UV work best after mechanical filtration and before sensitive return points. Better solids removal improves UV transmittance and reduces the ozone demand created by dissolved and fine organic matter.
The safest RAS designs treat UV and ozone as part of a controlled disinfection strategy, not as emergency fixes for weak system fundamentals.